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DEPARTMENT OF TERRESTRIAL MAGNETISM

J. A. Fleming, Director

Scientific Results of Cruise VII of the CARNEGIE during 1928-1929
under Command of Captain J. P. Ault

BIOLOGY- III

Studies in the Morphology, Taxonomy,
and Ecology of the Peridiniales

HERBERT W. GRAHAM

CARNEGIE INSTITUTION OF WASHINGTON PUBLICATION 542

WASHINGTON, D. C.
1942

This book first issued September 23, 1942

PREFACE

Of the 110,000 nautical miles planned for the seventh
cruise of the nonmagnetic ship Carnegie of the Carnegie
Institution of Washington, nearly one-half had been com-
pleted upon her arrival at Apia, November 28, 1929. The
extensive program of observation in terrestrial magnet-
ism, terrestrial electricity, chemical oceanography,
physical oceanography, marine biology, and marine me-
teorology was being carried out in virtually every detail.
Practical techniques and instrumental appliances for
oceanographic work on a sailing vessel had been most
successfully developed by Captain J. P. Ault, master and
chief of the scientific personnel, and his colleagues. The
high standards established under the energetic and re-
sourceful leadership of Dr. Louis A. Bauer and his co-
workers were maintained, and the achievements which
had marked the previous work of the Carnegie extended.

But this cruise was tragically the last of the seven
great adventures represented by the world cruises of the
vessel. Early in the afternoon of November 29, 1929,
while she was in the harbor at Apia completing the stor-
age of 2000 gallons of gasoline, there was an explosion
as a result of which Captain Ault and cabin boy Anthony
Kolar lost their lives, five officers and seamen were in-
jured, and the vessel with all her equipment was de-
stroyed.

In 376 days at sea nearly 45,000 nautical miles had
been covered (see map on p. v). In addition to the ex-
tensive magnetic and atmospheric-electric observations,
a great number of data and marine collections had been
obtained in the fields of chemistry, physics, and biology,
including bottom samples and depth determinations.
These observations were made at 162 stations, at an av-
erage distance apart of 300 nautical miles. The distri-
bution of these stations is shown in map, which deline-
ates also the course followed by the vessel from Wash-
ington, May 1, 1928, to Apia, November 28, 1929. At
each station, salinities and temperatures were obtained
at depths of 0, 5, 25, 50, 75, 100, 200, 300, 400, 500, 700,
1000, 1500, etc., meters, down to the bottom or to a max-
imum of 6000 meters, and complete physical and chemi-
cal determinations were made. Biological samples to
the number of 1014 were obtained both by net and by
pump, usually at 0, 50, and 100 meters. Numerous phys-
ical and chemical data were obtained at the surface.
Sonic depths were determined at 1500 points and bottom
samples were obtained at 87 points. Since, in accordance
with the established policy of the Department of Terres-
trial Magnetism, all observational data and materials
were forwarded regularly to Washington from each port
of call, the records of only one observation were lost
with the ship, namely, a depth determination on the short
leg from Pago Pago and Apia.

The compilations of, and reports on, the scientific
results obtained during this last cruise of the Carnegie
are being published under the classifications Physical
Oceanography, Chemical Oceanography, Meteorology,
and Biology, in a series numbered, under each subject I,
II, m, etc.

A general account of the expedition has been prepared
and published by J. Harland Paul, ship's surgeon and ob-
server, under the title The last cruise of the Carnegie.
and contains a brief chapter on the previous cruises of
the Carnegie, a description of the vessel and her equip-
ment, and a full narrative of the cruise (Baltimore, Wil-
liams and Wilkins Company, 1932; xiii + 331 pages with

198 illustrations).

The preparations for, and the realization of, the pro-
gram would have been impossible without the generous
cooperation, expert advice, and contributions of special
equipment and books received on all sides from inter-
ested organizations and investigators both in America
and in Europe. Among these, the Carnegie Institution of
Washington is indebted to the following: the United States
Navy Department, including particularly its Hydrographic
Office and Naval Research Laboratory; the Signal Corps
and the Air Corps of the War Department; the National
Museum, the Bureau of Fisheries, the Weather Bureau,
the Coast Guard, and the Coast and Geodetic Survey; the
Scripps Institution of Oceanography of the University of
California; the Museum of Comparative Zoology of Har-
vard University: the School of Geography of Clark Uni-
versity; the American Radio Relay League; the Geophys-
ical Institute, Bergen, Norway; the Marine Biological
Association of the United Kingdom, Plymouth, England;
the German Atlantic Expedition of the Meteor . Institut
fur Meereskunde, Berlin, Germany; the British Admiral-
ty, London, England; the Carlsberg Laboratorium, Bu-
reau International pour I'Exploration de la Mer, and
Laboratoire Hydrographique, Copenhagen, Denmark; and
many others. Dr. H. U. Sverdrup, now Director of the
Scripps Institution of Oceanography of the University of
California, at La JoUa, California, who was then a Re-
search Associate of the Carnegie Institution of Washing-
ton at the Geophysical Institute at Bergen, Norway, was
consulting oceanographer and physicist.

In summarizing an enterprise such as the magnetic,
electric, and oceanographic surveys of the Carnegie and
of her predecessor the Galilee , which covered a quar-
ter of a century, and which required cooperative effort
and unselfish interest on the part of many skilled scien-
tists, it is impossible to allocate full and appropriate
credit. Captain W. J. Peters laid the broad foundation of
the work during the early cruises of both vessels, and
Captain J. P. Ault, who had had the good fortune to serve
under him, continued and developed that which Captain
Peters had so well begun. The original plan of the work
was envisioned by L. A. Bauer, the first Director of the
Department of Terrestrial Magnetism, Carnegie Institu-
tion of Washington; the development of suitable methods
and apparatus was the result of the painstaking efforts of
his co-workers at Washington. Truly, as was stated by
Captain Ault in an address during the commemorative
exercies held on board the Carnegie in San Francisco,
August 26, 1929, "The story of individual endeavor and
enterprise, of invention and accomplishment, cannot be
told."

Dr. H. W. Graham, who succeeded H. R. Seiwell as
chemist and biologist, had charge of the biological work
on board the Carnegie from August, 1929, until the loss
of the vessel at Apia, Samoa. After his return to this
country. Dr. Graham was placed in charge of the biolog-
ical collections, attending to their subsequent care, se-
gregation, and distribution to various specialists for ex-
amination and report, he himself undertaking the not in-
considerable task of reporting upon the Peridineae
(Dinoflagellata).

Except for the Family Ceratocoryaceae (consisting
of one genus, seven species) and the Family Goniodoma-
ceae (one monotypic genus), which have been more or
less monographically treated in their entirety, this paper

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PREFACE

is but preliminary to a report on the Peridiniales col-
lected during the last cruise of the Carnegie . Otherwise,
only certain species of three other families (Peridinia-
ceae, Gonyaulaceae. Ceratiaceae) of the fourteen fami-
lies into which the order is subdivided are dealt with.
However, Dr. Graham's studies are of fundamental im-
portance to any adequate understanding of the structure
and relationships of the species and higher categories of
the Peridiniales. These studies were undertaken with
that particular purpose in mind. His discussion of the
selected species is well illustrated and gratify ingly com-
plete.

Further details regarding the procedure foUow<;d in
making the tow-net hauls at the various oceanographic
stations are given in the first volume of the Biological
Reports of this series, "The copepods of the plankton
gathered during the last cruise of the Carnegie, " by
Charles Branch Wilson (1942).

This manuscript was completed by Dr. Graham in
1938. Thus some papers printed since then are not con
sidered.

J. A. Fleming
Director, Department of Terrestrial Magnetism

H.

CONTENTS

Abstract

Introduction

General Discussion . . .
Material and Methods

Page
1
. 2
. 3
. 3

Survey of the Order Peridlniales 4

General Statements 4

Families 4

Genera 5

State of Knowledge of Morphology 5

Forms Treated in This Report 6

Relationships among the Genera 6

General Considerations 6

Ventral Area 7

Girdle 9

Hypotheca 9

Epitheca 9

Summary 9

Systematic Discussion 11

Family Peridiniaceae 11

Genus Peridinium 11

P. depressum Bailey and Related Forms . 15

P. depressum 18

P. depressum var. parallelum 21

P. depressum var. rectius 22

P. depressum var. convexius 23

P. depressum f. bisintercalares .... 23

P. depressum f. multitabulatum 23

P. claudlcanoides 24

P. oceanicum 24

P. oceanicum var. tenellum 25

P. oceanicum f. spiniferum 26

P. oceanicum f. bisintercalares 26

P. oceanicum f. tricornutum 27

Page

P. crassipes 27

P. truncatum 30

P. truncatum forma acutum 32

P. pallidum 32

Family Ceratocoryaceae 34

Genus Ceratocorys 34

Subgenus Euceratocorys 38

C. horrida 38

C. armata 40

C. reticulata 42

C. aultii 42

C. bipes 43

Subgenus Protoceratocorys 43

C. skogsbergii 44

C. gourretii 44

Family Goniodomaceae 45

Genus Goniodoma 45

G. polyedricum 46

Family Gonyaulacaceae 47

Genus Gonyaulax 47

G. pacifica 48

G. fusiformis 50

Genus Acanthogonyaulax 52

A. spinifera 53

Genus Spiraulax 54

S. kofoidii 55

Family Ceratiaceae 56

Genus Ceratium 56

C. pavillardii 56

Tables 59

Bibliography 91

Figures 95

Index 129

vii

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

By Herbert William Graham

Abstract

Although the Peridineae (Dinoflagellata) have been
rather extensively studied, there is still very little
known about many aspects of this interesting group of
the Protista. The purpose of this paper is to contribute
to our knowledge of the morphology, taxonomy, and ecol-
ogy of this group.

It was the author's privilege to have the opportunity
to study the Peridineae of the plankton samples collect-
ed on the last world cruise of the nonmagnetic research
vessel Carnegie of the Department of Terrestrial Mag-
netism, Carnegie Institution of Washington. The exten-
sive nature of this collection not only permitted a de-
tailed taxonomic analysis of a large variety of species,
but also afforded a good opportunity to make a study of
the geographic distribution of these forms throughout
the Pacific and North Atlantic oceans, based on compar-
able material. The simultaneous collecting of biologi-
cal samples and hydrographic data also offered a rare
opportunity to correlate the established distributions
with oceanographic conditions.

The present paper deals with twenty-nine repre-
sentatives of the order Peridiniales. They are distrib-
uted among the families of the order as follows: one in
Goniodomaceae; seven in Ceratocoryaceae; four in Gon-
yaulacaceae; sixteen in Peridiniaceae; and one in Cer-
atiaceae. They include six new species, three new vari-
eties, and six new forms. Two old specific names were
replaced and one subgenus raised to the rank of genus.
A monographic treatment was given all the species
(seven) of the family Ceratocoryaceae.

The species selected were subjected to a morpho-
logical analysis with the following objects in mind: (1)
to establish a standard for the analysis and recording
of the skeletal features of peridinian species; (2) to ac-
quire a knowledge of the detailed skeletal morphology
of certain species; (3) to study variation within the
group by subjecting a few forms to intensive analysis;
and (4) to contribute to the concepts of the relationships
of the genera of the peridiniales. In addition to this
morphological and taxonomic treatment, each species
was studied from the standpoint of geographic distribu-
tion and relationships to the following hydrographic
conditions: temperature, salinity, hydrogen-ion concen-
tration, and phosphate content.

Much of the confusion among systematists in the
past regarding the Peridineae has been due to inade-
quate descriptions and figures. Since type specimens of
peridinians usually cannot be preserved, it is impera-
tive that the descriptions and figures of the species be
not only complete but standard in nature so that ade-
quate comparisons with other material can be made.
Standard methods of measurement and of expression of
body shape were introduced in the case of each genus
studied.

The skeletal features of the forms treated were
very carefully analyzed by microdissection. Particular
attention was given the ventral area, a region of the
theca of the Peridiniales which was almost unknown be-
fore these investigations. A great diversity in the
structure of the ventral areas of the various genera was
found, although a common basic plan was evident. The

area is composed of from five to seven external plates
and, sometimes, one internal plate. A nomenclature
was devised for these plates which would serve to iden-
tify them and at the same time express homologies.

In some families of the Peridineae, species are
well defined and there is comparatively little difficulty
in determining them. In other groups, however,. specific
variability is so striking that no investigator has yet
attempted a comprehensive taxonomic treatment. In the
Peridiniaceae, for instance, the plate pattern is so var-
iable that it cannot be successfully used for the differ-
entiation of genera, and the body shape so variable that
all attempts at specific segregation have failed. For this
reason, a statistical method was applied to certain rep-
resentatives of Peridlnium in order to determine its
efficacy in the delimitation of species. A large number
of specimens was measured; the body shapes were ex-
pressed numerically; and the frequency of the various
shapes was plotted. By this method groupings were ob-
tained which indicated the delimitation of species and at
the same time demonstrated the range of variation of
each species.

On the basis of the comparative study of the ventral
areas of the various genera it was concluded that Goni -
odoma is the most primitive genus; that Ceratocorys is
closely related to Goniodoma but somewhat more ad-
vanced; that Gonyaulax . Acanthogonyaulax , and Spiraulax
are decidedly more advanced and in addition are closely
related to each other; and that the genera Peridinlum
and Ceratium are highly specialized and, although relat-
ed, are developed along divergent lines. The compari-
sons of the girdle, hypotheca, and epithecal plates of
these genera corroborate the conclusions arrived at
from the study of the ventral area itself although these
results could not have been obtained by the study of
these last series of plates alone.

Some of the marine peridinians are useful in trac-
ing the movements of oceanic water masses. The dis-
tributions of the species treated in this report were ex-
amined in relation to hydrographic conditions in order
to ascertain the value of each species as an oceano-
graphic "indicator." Of the species treated, Ceratoco -
rys horrida and Goniodoma polyedricum were found to
be the most valuable indicators of hydrographic condi-
tions. Their distributions are closely correlated with
the temperature of the water and the species are suffi-
ciently common to make negative records of occurrence
significant.

Ceratocorys horrida was found throughout the trop-
ics and warm-temperate regions. Its limits of distrib-
ution were sharply marked and these limits coincided
with the 19° C isotherm. Thus, in an intensive oceano-
graphic investigation, an occasional record of this spe-
cies in water with temperature less than 19° would in-
dicate an intrusion of tropical water or of water mixed
with water of tropical origin.

Goniodoma polyedricum . on the other hand, is a very
common tropical species which can endure transfer into
regions of much cooler water. It occurred at practical-
ly all the Carnegie tropical stations (where the temper-
atures ranged from 20 to 30° C). It was carried into

INTRODUCTION

water with temperatures as low as 15° and 16° C off
Japan, off California, and in the southeastern Pacific.
In the Atlantic it was found near the British Isles in wa-
ter with temperatures as low as 12 °4 C. It was un-
doubtedly carried there in the North Atlantic West Wind
Drift. Thus, this species is an excellent indicator of
the intrusions of tropical water masses.

It was a notable fact that while the temperature
conditions appeared to regulate the distribution of many
species, no correlations could be found between the
chemical composition of the water and these distribu-
tions. The most striking result obtained in regard to
the relation between the chemical conditions and specif-
ic distributions was that some photosynthetic species

thrive equally well in water extremely poor in phos-
phate and in richer waters. The upper levels of vast
areas of the middle North Pacific are practically de-
void of phosphate. The concentration of phosphate ion
is less than 10 mg/m^, i.e., less than 10 parts of phos-
phate per billion parts of water. In the case of many
species studied, this area of low nutrient content was
not in any measure a barrier to distribution. Thus, it
is apparent that these species of peridinians can utilize
extremely low concentrations of nutrient salts. This
phenomenon is undoubtedly correlated with the normal
seasonal appearance of peridinians following the diatom
outbursts of northern waters during the spring and fall.

INTRODUCTION

In 1928 the Department of Terrestrial Magnetism
of the Carnegie Institution of Washington sent out its
nonmagnetic ship Carnegie on a world cruise of all the
major oceans exclusive of the Arctic. In addition to the
investigations of earth magnetism there was conducted
a program of oceanographic investigations. This pro-
gram included the collection of plankton samples and the
determination of hydrographic conditions at regular in-
tervals. Unfortunately, the cruise was brought to an
untimely end by the destruction of the vessel before it
had visited the Indian and Antarctic oceans. However,
162 stations were occupied over extensive areas of the
Pacific and North Atlantic oceans. In 1929 the author
was placed in charge of the biological work on board,
and at the termination of the cruise he was given charge
of the biological collections.

The extensive nature of the collections permitted,
not only a detailed taxonomic analysis, but also a study
of geographic distribution based on comparable materi-
al. The simultaneous collecting of biological samples
and hydrographic data also offered a rare opportimity to
study the relations between the pelagic organisms and
their environmental conditions.

After certain general quantitative studies of the
plankton were made, a study was begun which would lead
to a general knowledge of the plankton commimities in
the various regions and to a knowledge of the relation of
the individual planktons to each other and to environmen-
tal conditions. As a foundation for this it was necessary
first to compile lists of the species occurring at each
station.

As a preliminary to this program the organisms in
the samples were sorted according to groups and each
group was submitted to a systematist for identification
and analysis. The author selected the Peridineae (Dino-
flagellata) for his own special study.

These introductory remarks have been made in or-
der to give some idea of the origin of the material and
of the general scientific inquiry of which this report
forms a part. The discussion that follows is restricted
entirely to the peridinians.

It was originally planned to make a comprehensive
study of this group in the Carnegie collection mainly
from the standpoint of geographic distribution and ecol-
ogy. A florlstlc treatment, naturally, would be the foun-

dation for such a study. The analysis, however, was not
far advanced before it was realized that no thorough and
certain floristic treatment of the Peridineae was possi-
ble in the present state of the taxonomy of the group. It
was found that not a single genus of the group was cov-
ered by an exhaustive monograph which would enable
one to make identifications of the species with any de-
gree of certainty. As a consequence, the floristic anal-
ysis had to be preceded by a thoroughgoing taxonomic
study.

The present paper deals with a small part of the
peridinian problem of the Carnegie material. It pertains
to certain forms of the order Peridiniales which were
selected for study and subjected to a careful morpholog-
ical analysis with the three following objects in mind:
(1) to establish a standard for the analysis and the re-
cording of the morphology of peridinian species; (2) to
acquire a knowledge of the detailed skeletal morphology
of some of the species; (3) to study variation within the
group by subjecting a few forms to intensive analysis;
and (4) to contribute to the concepts of the relationships
of the genera of the Peridiniales.

The Carnegie material afforded interesting compar-
ative material because it contained not only rare tropi-
cal forms, but also temperate and subpolar material
from widely separated regions.

Assistance in the routine census of the samples and
In the preparation of preliminary camera lucida sketch-
es was given by Mrs. N. Bronikovsky. Most of the fin-
ished ink drawings and wash drawings were executed by
Mr. Charles A. Dawson. The investigations were car-
ried out at the Hopkins Marine Station, Pacific Grove,
California through the courtesy of Dr. W. K. Fisher, Di-
rector. Valuable critical advice was received through-
out the Investigations from Dr. Tage Skogsberg, under
whose direction the work progressed. The pursuance of
the investigations was made possible through the good
offices of Dr. J. A. Fleming, Director of the Department
of Terrestrial Magnetism of the Carnegie Institution of
Washington, who has been in charge of the oceanograph-
ic program of the Carnegie and who has lent his contin-
uous interest and support to the biological work. To all
these I wish to express my deep appreciation for their
sympathetic assistance in the furtherance of the work.

GENERAL DISCUSSION

MATERIAL AND METHODS

During the Carnegie expedition 162 "oceanographic
stations" and 69 "surface plankton stations" were oc-
cupied. The collecting program at each "oceanograph-
ic station' ' included the towing of a 1 meter plankton net
at the surface, and of 1/2 meter nets at 50- and 100-
meter depths. The upper half of the nets was construct-
ed of no. 10, the lower half of no. 15 silk bolting cloth.
The nets were towed for 1 hour. At the "oceanographic
stations," from station 11 on, duplicate quantitative
samples were taken with a Pettersson plankton pump.
At the "surface plankton stations" various types of silk
nets were used depending on the speed of the vessel, and
they were towed for different lengths of time.

Only open nets were used. This introduced a pos-
sibility of error in the census of the subsurface sam-
ples. This error, however, was not great as the length
of time the nets were towed at their respective depths
(1 hour) was so much greater than the length of time
required for raising the net (about 2 minutes). Thus,
unless there was a very pronounced density of popula-
tion in an upper stratum, the proportion of upper-level
organisms to the standard- level organisms would be
very low. The comparison of the hauls from the three
levels would reveal this.

It should be noted that all collections outside the
tropics were made in the summer time. The cruise was
planned so that the vessel would be in the lilgher lati-
tudes of each hemisphere in its respective summer in
order to avoid too rough weather. For that reason, the
distributional records show no winter records outside
the tropics.

The plankton samples were preserved and stored
in formalin. In the laboratory the peridlnian material
was treated with a solution of hypochlorite, from 10 to
50 per cent, according to the nature of the material as
established by experience. This reagent was applied in
order to dissolve the cell contents and to weaken the
thecal sutures so that the plates could be readily sepa-
rated. In some instances it caused a swelling of the
protoplast followed by premature rupture of the theca.
For this reason, drawings were made of the specimen
in various views with as much detail as could be made
out before the hypochlorite treatment. In cases where
there was ample material, portions of unsorted sample
were given the hypochlorite treatment, but where the
material was rare, single specimens were transferred
with a micropipette.

After the treatment with hypochlorite for a varying
length of time, depending on the material, the specimens
were washed in water and, in some cases, stained with
trypan blue. Specimens with oil droplets, such as Perl -
dlnlum depressum. were cleared with xylol in order to
dissolve the oil, which interfered with proper staining.
The specimen thus treated for study was transferred to
a warm flat drop of glycerin jelly by means of a micro-
pipette and examined without a cover glass. In this me
dlum the specimen could be oriented to any desired po-
sition, and, after the jelly cooled to room temperature

and hardened, the specimen was in a solid medium and
a camera lucida drawing could be made. After obser-
vation and drawing in one view, the jelly could be melt-
ed and the specimen reoriented any number of times.
The glycerin jelly was softened by placing it on a warm-
ing table heated to a temperature of 50° C. During
periods of warming, the drop was covered with a small
damp chamber to prevent undue evaporation of water
and consequent troublesome thickening of the jelly. The
specimen was manipulated by means of a micro-needle
prepared by mounting a piece of spun glass from a
glass-wool filter on the end of an ordinary dissecting
needle. The glass hair projected about 3 millimeters
beyond the point of the steel needle. As it became
clogged with jelly, it was trimmed with scissors until
about 1 millimeter long, when it was replaced.

The melting point of the glycerin jelly can be con-
trolled by varying the water content. All the water was
never allowed to evaporate on the warming table, how-
ever, as the jelly then had a tendency to become sticky
even though more water was added. The solution of jel-
ly kept on the warming table for the preparation of
slides was at all times covered, and water was added
occasionally to compensate for evaporation.

This method proved satisfactory for studying the
specimens in various positions without injuring them.
It is impossible to orient some material, for instance
Peridinium depressum. by rolling a specimen in a water
mount under a cover glass, because of the unbalanced
nature of the theca in all but four positions, none of
which is particularly desirable for descriptive purposes.
The above method also afforded a satisfactory means of
dissecting. A specimen which has been properly cleaned
in hypochlorite will begin to break apart in a glycerin-
jelly mount when pressure is applied with the glass hair
or when it is gently touched with a fine steel needle.
When the plates have beg^un to separate, an individual
plate or group of plates may be selected and oriented to
any desired position by stroking the surrounding jelly
with the glass hair, without danger of crushing or losing
the rest of the specimen. For the examination of details
Uke pores, when it is necessary to use an oil- immersion
objective, it is usually advisable to mount imderacover
glass in glycerin jelly, water, or balsam.

All drawings were made with the aid of a camera
lucida. In some cases they were later enlarged to facil-
itate shading.

Owing to the pronounced asymmetry of the body of
some of the forms, they presented quite different pro-
files in different positions. Thus, the measurement of
any contour may vary considerably even though the po-
sition of the body is changed but slightly. For this rea-
son it is necessary to adopt standard positions for mak-
ing measurements. In the present work the ventral view
has been adopted for the principal standard position.
There is some difficulty in determining the "ventral
view" in some of the more asymmetrical forms, partic-
ularly in species of Peridlniimi with long horns. In such

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

forms it is necessary to bear In mind that the ventral
view should be at right angles to the longitudinal axis,
which axis is defined as the line running through the ap-
ical horn and bisecting the hypotheca midway between
the bases of the antapical horns. It must be remembered
that when a specimen comes to rest at the bottom of a
drop of mounting fluid it does not present this view.
When a specimen of Peridlnium depressum comes to
rest with ventral side uppermost, it presents an antero-
ventral aspect, resting on the dorsal side of the girdle
and on the two antapical horns. This position should
not be used as the standard in measuring, since consid-
erable variation in the optical projection of the body is
caused by slight differences in the length or divergence
of the antapical horns on which the organism rests. It
is necessary to mount in glycerin jelly or similar me-
dium in order to orient the specimen in the proper man-
ner and arrange it in a proper position.

As defined in this work, the ventral view is the one
in which the sulcus lies midway between the lateral
sides of the body and in which the dorsal part of the gir-
dle can be superimposed on the anterior end of the sul-
cus when the microscope is focused downward.

Because of the very great differences in the shapes
of the various genera of the Peridlniales, it is not always
possible or desirable to make the same measurements

on all forms. There are particular dimensions which
are significant in each genus. A description of these
measurements and the method of making them will be
given in the introduction to each genus.

The question of nomenclature always arises in the
treatment of this group of organisms. The group has
been studied by both botanists and zoologists, each using
the nomenclature of his particular school. It seems
futile to discuss the question whether the members of
this group are plants or animals. They cannot be placed
unreservedly in either the plant or the animal kingdom.
We can only discuss their relative similarities to each
of these kingdoms. Since one is forced to adopt either
plant or animal nomenclature, It is only reasonable that
the nomenclature should fit the views of the author. This
author believes that the plant char acteristicsof the peri-
dinlans outweigh the animal. Hence, botanical nomen-
clature is used in this report. Many of the peridlnians
are photosynthetic and practically all show some signs
of a ceUulose-like substance in their body wall (All-
mann, 1855; Klebs, 1883; Schutt, 1895; Mangin, 1907,
1908). The discovery of two filamentous algae with
Gymnodlnium spores by Pascher (1914) supports the
interpretation of these forms as plants, but the discov-
ery of an amoeba with similar spores (Pascher, 1915)
tends to outweigh this discovery.

SURVEY OF THE ORDER PERIDINIALES

General Statements

The Peridlneae, or Dinoflagellata, are subdivided
into two main groups: the Adinlferae and the Dintferae,
the former without, the latter with a girdle, i.e., a body-
encircling transverse groove in which the transverse
flagellum is lodged. Diniferae are divided into seven
orders, one of which is the Peridlniales, to which the
material of this thesis belongs.

The Peridlniales may be characterized briefly by
the following features: The body is surrounded byathe-
ca, which is made up of definite polygonal plates (ex-
cept in prevalvate stages of Glenodiniaceae) of unequal
sizes and not arranged in a bilaterally symmetrical
manner. These features, especially the last one, sepa-
rate the Peridlniales from the Dinophysiales, which is
the remaining large order with thecate and plated body,
and in which the theca is divided longitudinally into right
and left valves.

The most recent synopsis of the Peridineae which
includes the Peridlniales is that of Lindemann (1928) in
Engler and Prantl's Pflanzenfamilien. Kofoid, who
worked extensively on the Peridineae, never treated this
order as a whole. Schiller's synopsis of the Dinoflagel-
lata (1931 to 1933) sUll lacks the part on the Peridlni-
ales.

Families

Lindemann (1928) divided the order into fourteen
families. Instead of giving abbreviated diagnoses of
these, a condensation of Lindemann's key for distin-
guishing these families is given below in order to offer
a brief survey of the order.

Key to the Families of the Peridlniales
(Lindemann, 1928, p. 79)

A. Shell tough- skinned; composed of unequally sized, in-
distinct, major polygons, not visible in young stages
Glenodiniaceae

A. Shell consists of more or less heavy armor composed
of dissimilar polygonal plates which are evident in
yoimg stages B

B. Girdle Indistinctly developed as a narrow band . .
Podolampaceae

B. Cell with very distinct girdle C

C. Cell in apical view quite or nearly circtilar; epitheca
distinctly smaller than hypotheca, flat, lid-shaped.
Either there are spinelike processes with a central
axis which extend in different directions (each about
as long as the body), or the antapical pole carries 2 to
3 strong spines D

C. Cell of other shapes; there are frequently processes
or spines but these are never so long as the body nor
with a central axis E

D. Processes or spines only on the hypotheca ....
Ceratocoryaceae

D. Both epitheca and hypotheca carry long processes .
Cladopyxlaceae

E. Girdle equatorial or anterior; only one plate at the
antapex, which terminates in a horn or spine . . .
Oxytoxaceae

E. Commonly at least two antapicals, or one antapical
and one posterior intercalary; rarely one antapical,
in which case there is no end spine or point . . F

F. Cell strongly flattened anteroposterlorly; antapicals
none or more than two G

F. Cell otherwise shaped H

G. AnUpical plates absent (?); longitudinal axis oblique

SURVEY OF THE ORDER PERIDINIALES

G. At least three antapical plates present

Pyrophacaceae

H. On ventral side of epitheca where intercalary striae
converge, there is a small but conspicuous field
with a porelike point Heterodlniaceae

H. Epitheca on the ventral side without such porelike
point I

I. Cell with two to four characteristic horns; one

apical, one to three antapical . . . Ceratiaceae
I. Cell not so shaped J

J. Theca so strongly reticulated on the surface that the
tabulation is not discernible . . Protoceratiaceae
]. Tabulation clearly evident K

K. Posterior intercalary present in addition to one ant-
apical Gonyaulacaceae

K. Two antapicals present Peridiniaceae

K. Three antapicals present, one dorsal, two ventral .
Goniodomaceae

K. Only one plate at the antapex; not drawn out . . L

L. Shape spherical, without apex . . Dinosphaeraceae
L. Cell flattened; apex present; comb near sulcus . .
Diplopsalis

Genera

The genera of the Peridlniales are described prin-
cipally on the basis of the number and arrangement of
the thecal plates. For purposes of terminology these
plates can be arranged more or less in rows running
parallel to the girdle. In this report the terminology of
Kofoid (1909) has been followed. On the epitheca, ante-
rior to and touching the girdle, is a row of plates, the
precingular series. Another group of plates, touching
. the apex, is designated the apical series. Between
these two rows there may be interpolated plates called
the anterior intercalaries. The girdle itself is made up
of a series of plates. On the hypotheca there is a row
bordering the girdle called the postcingular series.
Another series, touching the antapex, is called the ant-
apical plates. Between these and the postcingular ser-
ies there may be interpolated other plates which are
designated the posterior intercalaries. In the plate for-
mulas the names of these plates have been abbreviated
in the present paper as follows:

apical platelet - pi postcingular - po

apical plate - ap posterior intercalary - p

anterior intercalary - a antapical - ant

precingular - pr sulcal - s
girdle - g

These abbreviations are clearer and more rapidly read
than the prime signs used by Kofoid (1909).

The following list of genera of the Peridlniales is
compiled chiefly from Lindemann (1928). There is con-
siderable uncertainty in regard to the limits of some
genera. For example, the genus Diplopsalis includes
five genera considered distinct by some authors. The
plate formula is given as far as is known for each genus.

Acanthogonyaulax (Kofoid) nobis. Sap, Oa, 9pr, 6g, 7s,

6po, lant.
Amphidoma Stein, 1883. 6ap, Oa, 6pr, 6g, ?s, 6po, Ip, lant.
Blepharocysta Ehrbg., 1873. 2ap, l-2a, 6pr, ?g, ?s,

3po, 3ant.
Centrodinium Kofoid, 1907. 2ap? Oa, 6pr, ?g, ?s, 5po,

Ip, 4ant.
CeraUumSchrank, 1793. 4ap, Oa, 5pr, 4g, ?s, 5po, Op, 2ant.
Ceratocorys Stein, 1883. 2ap, 2a, 5pr, 6g, 5-6s, 5-6po,

Cladopyxis Stein, 1883. 4ap, Oa, 8pr, ?g, ?s, 6po, Op,

2ant.
Congruentidium Ab^, 1927. 4ap, la, 5pr, ?g, ?s, 5po,

Ip, 2ant.
Dinosphaera Kofoid and Mich., 1912. 3ap, la, 6pr, 6g,

?s, 5po, Op, lant.
Diplopsalis Bergh, 1882. 3-4ap, 0-2a, 6-7pr, ?g, ?s,

5po, Op, l-2ant.
Dolichodinium Kofoid and Adamson, 1933. 4ap, Oa, 6pr,

6g?, ?s, 6po, Op, 3ant.
Glenodinium Stein, 1883. Variable pattern.
Glenodiniopsis Wolosz., 1916. 7ap?, Oa?, 8pr, ?g, ?s,

7po, 2ant.
GonyaulaxDiesing, 1886. Formula for genus uncertain.
Goniodinium PaviUard, 1927c. 4ap, Oa, 6pr, 9g?, ?s,

6po, 2a, 3 ant.
Goniodoma Stein, 1883. Sap, Oa, 7pr, 6g, 5s, 5po, Op, 3ant.
Heterocapsa Stein, 1883. 4ap, 2a, 6pr, ?g, ?s, 5po, Op,

2ant.
Heterodinium Kofoid, 1906. Sap, la, 6pr, 6 (7?) g, ?s,

7po, Op, 3ant.
Lissodinium Matzenauer, 1933. S(2?)ap, Oa, 5pr, ?g,

?s, 5po, 4ant.
Murrayella Kofoid, 1907. 2-4ap, la, 6pr, ?g, ?s, 4po,

Op, lant.
Ostreopsis J. Schmidt, 1901. Sap, Oa, 7-8pr, ?g, ?s,

4po?, lant?
Oxytoxum Stein, 18 8S. Sap, Oa, 5pr, ?g, ?s, 5po, Op, lant.
Pachydinium Pavillard, 1915. 3ap, Oa, 5pr, ?g, ?s, 5po,

Op, Sant.
Peridiniella Kofoid and Mich., 1911. 4ap, Sa, 7pr, 6g,

?s, 6po, Ip, lant.
Peridinium Ehrbg., 1840. 2-5ap, 0-8a, 6-7pr, 3-6g, 5-

6s, 5-6po, Op, 2ant.
Podolampas Stein, 1883. 2ap, la, 6pr, ?g, ?s, Spo, 4ant.
Protoceratium Bergh, 1882. 2ap, Oa, 6?pr, 6?g, ?s,

6po, Op, Sant.
Pyrodinium Plate, 1906. 3ap, Oa, 6-7pr, 8g, ?s, 5po,

Ip, lant.
Pyrophacus Stein, 1883. 5-9ap, 2?a,9-13pr, ?g, ?s, 9-13

po, 0-2p, 3-4ant.
Spiraulax Kofoid, 1911. 4ap, la, 6pr, 6g, 6s, 6po, Ip,

lant.

State of Knowledge of Morphology

In the above list there are thirty genera covering
more than five hundred species. Although the generic
classification of these species is based primarily on the
plate pattern, our knowledge of this feature is far from
complete, as can be seen by a glance at the above list.
Many generic diagnoses are based on the analysis of
only one or a few species. In many cases the tabulation
given by the authors is admittedly only approximate.
Some of the recorded generic plate formulas are decid-
edly incomplete; e.g., for five genera not even the major
plates of the epitheca and hypotheca have been reported
with certainty. Among those genera for which formulas
of the major epithecal and hypothecal plates have been
reported without reservation, seventeen have not had the
number of girdle plates reported or this number is un-
certain. In only three genera had the ventral area been
investigated before the present work.

Under these conditions it is a matter of course that
all the generic diagnoses may be subjected to more or
less radical alterations on the application of more crit-
ical morphological analysis. Further, a more extensive
study of the various species will undoubtedly result in
revised concepts of genera as weU as of species.

Over 1200 papers have been written on the Peridin-
eae. More than 900 of these contain systematic or flo-

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

ristic treatments of some group or groups of the Peri-
dineae; the remaining 300 deal with cytological, ecolog-
ical, and physiological problems. Of the systematic
papers, less than 5 per cent present critical analytical
treatments of the species from either the taxonomic or
the morphologic viewpoint.

Forms Treated in this Report

Of the fourteen families in the order Peridiniales,
this report deals with representatives of five. A mono-
graphic treatment has been given of the monogeneric
family Ceratocoryaceae. This was due to the fact that
ample material was available for making a complete
skeletal analysis of every known species. Whereas in
Ceratocoryaceae species are not difficult to define, in
the family Peridiniaceae the species seem to be in an
\instable condition; extreme variability frequently
makes a delimitation of species a difficult task, indeed.
One genus in this family was selected for study, viz.,
Peridinium . Of its two hundred or more species, those
related to Peridinium depressum Bailey were selected
for intensive studies of the variation in body shape and
plate pattern. Representatives from other parts of this
large genus were also analyzed, viz., P. crassipes Ko-
foid, P. truncatum n.sp., and P. pallidum Ostenfeld. In
an attempt to probe further into the interfamily rela-
tionships, work was also done on three other families:
Ceratiaceae, Goniodomaceae, and Gonyaulacaceae. One
species from each of the first two was investigated, viz.,
Ceratium p avillardii Jorgensen and Goniodoma polyedri -
cum Pouchet; and from the family Gonyaulacaceae four
species were analyzed: Gonyauiax pacifica Kofoid, Gon-
yaulax fusiformis n.sp., Acanthogonyaulax spinifera
(Murray and Whitting) Graham, and Spiraulax kofoidii
new name.

Of the twenty-nine forms treated in this paper,
there are six new species, three new varieties, and six

new forms. Two old specific names have been replaced.

Following is a complete list of the forms included
in this report:

Family Goniodomaceae
Goniodoma polyedricum Pouchet

Family Ceratocoryaceae
Ceratocorys horrida Stein
C. armata (Schutt) Kofoid
C. reticulata n.sp.
C. aultii n. sp.
C. bipes (Cleve) Kofoid
C. skogsbergii n. sp.
C. gouretii Paulsen

Family Gonyaulacaceae
Gonyauiax pacifica Kofoid
G. fusiformis n.sp.
Acanthogonyaulax spinifera (Murray and Whitting)

Graham
Spiraulax kofoidii new name

Family Peridiniaceae
Peridinium depressum Bailey
P. depressum var. parallelum Broch
P. depressum var. rectius n. var.
P. depressum var. convexius n. var.
P. depressum f. bisintercalares n.f.
P. depressum f. multitabulatum n.f.
P. claudicanoides n.sp.
P. oceanicum Vanhoffen
P. oceanicum var. tenellum n.var.
P. oceanicum f. spiniferum n.f.
P. oceanicum f. bisintercalares. n.f.
P. oceanicum f. tricornutum n.f.
P. crassipes Kofoid
P. truncatum n.sp.
P. truncatum f. acutum n.f.
P. pallidum Ostenfeld

Family Ceratiaceae
Ceratium pavillardii Jorgensen

RELATIONSHIPS AMONG THE GENERA

General Considerations

Our ideas of the relationships of the genera must at
present be based on the degree of similarity in the skel-
etal structures, since the cytology of the order is alto-
gether too little known to be used for this purpose. For-
tunately, the skeletons of these forms are complex and
hence present a multitude of morphological characters
useful in taxonomic studies. These characters have not
been the basis for any satisfactory discussion of inter-
generic relationships; indeed, so far no one has ventured
Into such a discussion. Ideas concerning these relation-
ships have been expressed only by the grouping of the
genera into families, without any discussion of the justi-
fication for doing so (see, however, Lebour, 1922, on the
origin of Peridinium ).

The absence of such evolutionary studies is proba-
bly due to the apparent lack of order in the great varie-
ty of plate patterns which are presented by the various
genera. It is extremely difficult to select, from this
kaleidoscopic array of patterns, characters which are of
fundamental generic or family Importance. As stressed

above, however, the incompleteness and undoubted inac-
curacies in our knowledge of the skeletal features have
greatly aggravated this situation. Doubtless the situation
in nature is not so chaotic as present knowledge indicates.

The skeletal features which are the most fundamen-
tal from the standpoint of taxonomy are the number and
arrangement of the thecal plates. The body shape, the
lists and spines, and other such characters are of sec-
ondary importance.

In regard to the number of plates, there are variouf
ways in which evolution may have taken place. For in-
stance, primitive forms may have had relatively few
plates and evolution may have progressed by the split-
ting of plates or by the insertion of newly formed plates;
or the primitive forms may have had a large number of
plates and evolution may have proceeded by the fusion
and loss of plates; or the processes of Increase and de-
crease may have taken place simultaneously in different
parts of the body.

Whatever has been the progress of evolution, it has
not been uniform or parallel in all parts of the theca.
Today there are some genera with the same number of

RELATIONSHIPS AMONG THE GENERA

plates in the hypotheca as in the epitheca ( Heterodlni -
um), some with more plates in the hypotheca ( Centro -
dinium), and the majority have more in the epitheca
than in the hypotheca. This is an expression of the well-
known principle of the independent evolution of particu-
lar organs or organ systems which is so amply illus-
trated throughout the Metazoa.

In regard to the arrangement of plates it is even
more difficult to attempt a reconstruction of evolution-
ary trends than in the case of the number of plates. We
do not know of any forms which represent definite tran-
sitional stages between the unarmored Dinoflagellata
and the Peridiniales. Thus, we have no reasonably cer-
tain information as to which are the most primitive pat-
terns. As a consequence, we find ourselves forced to
undertake a search for features which are more or less
universal, and to start from the assumption that such
characters represent the primitive condition.

The peridinian skeleton is divided naturally into
four parts and, for purposes of evolutionary discussions,
it is advisable to consider these separately. They are:
the epitheca, the hypotheca, the girdle, and the ventral
area.

Because of the unreliability of many of the pub-
lished generic diagnoses, the present discussion of re-
lationships is based entirely on the forms treated in this
report. The skeletal features of these are known with
certainty. Since the ventral area has been the main tar-
get in the present work and, since the comparison of the
ventral areas has been the most fruitful in showing in-
tergeneric relationships, it will be taken up first.

Ventral Area

The ventral area was almost unknown in the Peri-
diniales when this investigation was started. Since then,
however, Abe (1936) has begun a reclassification of the
genus Peridinium on the basis of the structure of this
region, and Tai and Skogsberg (1934) have demonstrated
the importance of this feature in the Dinophysiales.

A study of this area in various genera of the Peri-
diniales has shown that there is a rather small and fair-
ly constant number of plates, and that the shape and ar-
rangement of these plates differ fundamentally in the
different genera.

General shape. There has been an extensive evolu-
tion of the general contours of the ventral area in the
Peridiniales. The area is seen in its simplest form in
Goniodoma . where it is comparatively flat and lacks in-
tricate structures. Furthermore, In this genus there is
no distinct delimitation of the sulcus proper. In Cerati-
um the ventral area is specialized, being broad and rel-
atively large, with extremely hyaline plates and with a
small sulcus on the left side. In the other genera inves-
tigated, there is a deep sulcal groove, in many cases so
deep and narrow that no indication of the tabulation can
be ascertained without dissection. In Spiraulax, Gon -
yaulax fusiformis , and Acanthogonyaulax the posterior
part of the ventral area flares out into more or less ex-
panded areas which cannot be considered part of the sul-
cus proper. In Peridinium this does not occur and the
sulcus proper is usually limited. In this case the sulcus
usually lies to the left side of the ventral area, although
there is considerable variation in this respect within the
genus. In P. truncatum , for example, the right sulcal
plate is on a level with the major body plates, as is also
the left limb of the posterior plate, and the left sulcal

plate is turned in so that it forms the side wall of a
deeply embedded groove.

In most of the forms of the Peridiniales represent-
ed in this report the two sides of the body are about
equal in size, and as a consequence, the ventral area
appears in or near the mid-ventral line when the organ-
ism presents the ventral view. In Gonyaulax pacifica,
on the other hand, a differential growth has taken place
by which the left side has grown decidedly larger than
the right. A consequence of this is that when the organ-
ism presents the ventral aspect, the ventral area lies
decidedly to the right and the axis of the sulcus has been
so rotated that only the plates of the right side are visi-
ble.

Plate pattern. The ventral area in the forms investi-
gated is composed of from five to seven external plates.
(Fig. 1.) As regards homologues, however, there are
eight plates, as is shown by the fact that in Acanthogon -
yaulax , which has seven plates, there is a left acces-
sory but no posterior accessory; and in Gonyaulax pa-
cifica, which also has seven plates, there is a posterior
accessory but no left accessory.

Thus, the generalized composite picture of the ven-
tral area has eight external plates. These are: an ante-
rior, a posterior, a left and a right, with accessories to
the left, right, and posterior, plus an intercalary in the
right posterior region. All border on the flagellar pore
except the posterior sulcal (Goniodoma excepted) and
the intercalary sulcal. In addition to these external
plates, in Peridinium there is an internal plate lying
along the right side of the pore.

The anterior sulcal plate (as, fig. 1) forms the ante-
rior edge of the pore in all genera except in Acantho -
gonyaulax . where it has migrated anteriorly. The ante-
rior plate in all cases lies against the proximal end of
the girdle and in some genera it forms a distinct part of
the girdle, as, for instance, in Goniodoma . Frequently
this plate has a considerable extension into the epitheca,
viz., in Goniodoma , Gonyaulax . and Spiraulax . In Peri -
dinium the anterior plate bears part of the anterior in-
ternal process. It can be concluded that the anterior
sulcal plate is an important plate in the thecal complex
of the peridinian skeleton. It is a conservative plate,
occupying a key position at the head of the flagellar pore,
at the proximal end of the girdle, and in the epithecal
pattern. Only in Acanthogonyaulax is it removed from
its position at the head of the pore, but even in this ge-
nus it lies at the proximal end of the girdle. Its shape
varies considerably from genus to genus, but none of the
differences are radical. It may be squarish to linear
with various numbers of sides or irregularities. Fre-
quently the anterior cingular list is extended across it,
as in Goniodoma and Gonyaulax .

The posterior sulcal p late (ps, fig. 1) is another im-
portant element. It is conservative in being always
present, but it has undergone a much greater diversifi-
cation than the anterior sulcal plate. It is always re-
moved from the flagellar pore except in Goniodoma . In
most genera it flares out into a relatively wide expanse
on the ventral aspect of the hypotheca. This expansion
may be elliptical ( Gonyaulax and Spiraulax ) or winged
(Acanthogonyaulax ) . In Ceratocorys it is rather obscure,
being rectangular and not wider than the anterior part of
the sulcus. It attains its greatest complexity in the ge-
nus Peridinium . where it is very intricate and lies at
the posterior end of a deep sulcal groove. In this genus
it Is more or less horseshoe-shaped with a narrow cen-

8

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

tral part, a wide right limb lying posterior to the right
sulcal plate, and a narrow or wide limb on the left side
running along the left side of the left sulcal plate. In
some species (P. truncatum) it assumes a size equal to
that of some of the major body plates. It bears some of
the elements of the more complicated list systems of
the Peridiniales.

The left sulcal plate (Is, fig. 1) is present in all ge-
nera. It has undergone little evolution of shape, but
varies in position in the sulcal tabulation. It is always
anterior to the posterior plate, however, and on the left
side of the area, and it always borders the flagellar
pore. It may form the entire left edge of the pore, as
in Peridinlum and Goniodoma ; it may form the posteri-
or edge and part of the left edge of the pore, as in Gon -
vaulax ; or it may form only the posterior edge of the
pore as in Spiraulax and Ceratocorys ; or only part of
the posterior edge, as in Acanthogonyaulax .

In only one genus, Acanthogonyaulax . is there a left
accessor y sulcal plate (la, fig. 1). This lies not contig-
uous ta the left sulcal plate, but anterior to the flagel-
lar pore on the left side of the sulcus.

On the right side of the ventral area there may be
from one to three plates between the anterior and the
posterior; viz., one in most species of Peridinium . two
in Goniodoma . Ceratocorys . and Peridinium pallidum ,
and three in Gonyaxilax . Acanthogonyaulax , and Spirau-
lax. When only one plate is present, it is the right sul -
cal plate (rs, fig. 1). Anterior to this plate there may
be a right accessor y sulcal p late (ra, fig. 1); posterior
to it, an intercalar y sulcal plate (i, fig. 1). Either the
right or the right accessory, or both, borders the pore,
but the intercalary never does. Sometimes the right
is not in contact with the pore, as in Goniodoma and
some species of Ceratocorys . In such cases the right
accessory and the anterior sulcal plates form the right
edge of the pore. In addition to these seven plates there
is frequently an eighth, the p osterior accessor y sulcal
plate (pa, fig. 1). This lies between the posterior edge
of the pore and the posterior plate as in Peridinium . or
it may be squeezed out of contact with this plate as in
Gonyaulax pacifica . It occurs only in these two genera.

Discussion . It is obvious that there is a great
diversity in the tabulations of the ventral areas of the
various genera in the Peridiniales. In spite of this
diversity, however, a common basic plan is evident.

After a careful comparison of the ventral areas of
the various genera, a type of tabulation was devised
which may represent an approximation of the ancestral
condition (fig. lA). This reconstructed ventral area is
quite similar to that of Goniodoma with the major ex-
ception that its posterior sulcal plate does not touch the
flagellar pore. Since all genera except Goniodoma have
this plate removed from the pore, Goniodoma must be
considered aberrant in this respect. This primitive
ventral area is thus composed of five plates: an anteri-
or sulcal, a posterior sulcal, a right and a left sulcal,
and a right accessory sulcal. These plates are approx-
imately equal in size and all border the pore except the
posterior sulcal. The sulcal ring is complete.

If this reconstruction of the ancestral ventral area
is used as a key, a comparison of this area in the vari-
ous genera yields the following results:

Goniodoma : This is, without doubt, the most prim-
itive of the genera investigated, since its ventral area

is the simplest of those studied, being different from the
ancestral condition only in having the posterior plate
touching the flagellar pore. Its ventral area is very
simple in outline and contour; the flagellar pore is ful-
ly exposed; there are no internal skeletal structures;
and the sulcal lists are poorly developed. There are
only five plates. These are subequal in size and show
no complex contours. The sulcal ring is complete.

Ceratocorys : The genus Ceratocorys is evidently
closely related to Goniodoma. The sulcal plates, also
five, are simple in structure, and apparently are homol-
ogous with the five present in Goniodoma . There has
been a narrowing of the sulcus, however, and a slight
enlargement of the posterior sulcal plate. The sulcal
ring has broken on the left side and the posterior sulcal
plate has taken up a position posterior to the right sul-
cal plate so that it alone forms the posterior end of the
area. The last two characters are carried through the
other genera except that the ring is not broken in Peri -
dinium . Thus although Ceratocorys is closely related
to Goniodoma . it represents a definite advance over that
genus.

Gonyaulax . Acanthogonyaulax . Spiraulax: These ge-
nera show striking similarities. Their ventral areas
are greatly elongated and sigmoid in outline, with great-
ly enlarged posterior sulcal plate. The number of plates
has increased to six or seven. The sulcal ring is bro-
ken. The sulcus proper is a narrow groove occupying
only part of the ventral area. All the plates of the
primitive area are present, and in addition, there is an
intercalary lying on the right side between the right and
the posterior sulcal plates. In addition to these, Gon -
yaulax pacifica has a posterior accessory plate just
posterior to the pore. In Acanthogonyaulax there is a
left accessory sulcal plate just anterior to the pore, and
the anterior sulcal plate is unique in being removed
from the pore.

Peridinium. Ceratium : These two remaining gene-
ra are widely divergent from the previous genera and
each of them is unique in regard to its sulcal structures
In Peridinium the primitive number of external plates,
i.e., five, has been retained, except in P. pallidum ; and
the sulcal ring is unbroken. Each sulcal plate, however,
is singularly modified, particularly the posterior, and
internal sulcal structures have developed. Sulcal lists
are prominent and the sulcus proper is deeply embed-
ded in the left side of the area in such a way that it is
not exposed to view. Ceratium is characterized by the
development of a wide and large flat ventral area ex-
tending over the ventral side of the body, and covered
by hyaline plates. This type is to be found nowhere else
in the Peridiniales.

It can be concluded from the above studies that
Goniodoma represents the most primitive genus inves-
tigated; that Ceratocorys is closely related to it but is
somewhat more advanced; that Gonyaulax , Acanthogon -
yaulax . and Spiraulax are decidedly more advanced and
in addition are closely related to each other; and that
the genera Peridinium and Ceratium are highly special-
ized and developed along divergent lines.

Thus, the genera cannot be arranged in a single
evolutionary series. Evolution has apparently prog-
ressed in divergent directions within the order and these
divergent directions are expressed by an apparently
natural grouping of the genera.

RELATIONSHIPS AMONG THE GENERA

The Girdle

The number of girdle plates has not been generally
determined by previous workers, and has frequently
been omitted from generic plate formulas. Therefore,
this feature is known for only a limited number of ge-
nera. This is the more deplorable since there are in-
dications from the present investigations that the num-
ber of girdle plates may be important from a taxonomic
standpoint.

All the genera treated in this report have six gir-
dle plates except Peridinium and Ceratium, which have
four. Six is also recorded for certain other genera not
treated in this report. Other numbers have been ques-
tionably reported (see p. 3), but these aberrant num-
bers must be checked by careful dissection before they
can be included in evolutionary discussions. The num-
ber is thus apparently constant and it is probable that
six is the primitive number. Any deviation from this
number should, at least for the present, be interpreted
as a divergent feature.

In regard to the relationships among the genera
treated here, the number of girdle plates fits into the
scheme devised by a comparison of the ventral areas
and, at the same time, indicates a greater unity in the
order as a whole. The six girdle plates in Goniodoma ,
Ceratocorys . Gonyaulax , Acanthogonyaulax , and Spirau -
lax bring these genera more closely together. The di-
vergent number, four, in Peridinium and Ceratium cor-
roborates the previous conclusion that these two genera
have been separated from the ancestral form for a long
period of time.

The Hypotheca

When considering the hypotheca, we have to deal not
only with the number of plates, but also with the pattern
which these plates assume. For intergeneric studies it
is sufficient to limit the discussion of patterns to a con-
sideration of the number of plates in the individual ser-
ies, inasmuch as the relative positions of the plates and
the course of the sutures are usually of specific value
only. Thus, the expression of plate pattern is itself re-
duced to numbers.

Table 1. Comparison of number of plates in the four
parts of the theca of the genera treated in
this report

Genera

Epi-
theca

Hypo-
theca

Girdle

Vent,
area

Total

Goniodoma 11

Ceratocorys 10

Gonyaulax 12

Acanthogonyaulax . . 13

Spiraulax 12

Peridinium 16

Ceratium 10

8

6

5

30

8

6

5

29

8

6

6-7

33

8

6

7

34

8

6

6

32

7

4

5-6

32-33

7

4

?

21+

In regard to the total number of plates in the hypo-
theca, the genera treated here are divided into two
groups (see table 1). The first group has eight plates
and includes all the genera except Peridinium and Cera -
tium . The second group has seven plates and Includes
these two genera. There is a striking parallelism here
with the number of girdle plates, which substantiates the
assumptions based on the comparison of ventral areas
alone that Peridinium and Ceratium are divergent from
the other genera.

In regard to me tabulation of the hypotheca a simi-
lar grouping is indicated, except that Goniodoma is sep-
arated from related genera (see table 2). There are,
thus, three groups: Goniodoma with hypothecal formu-
la 5po, Op, 3ant; Ceratocorys. Gonyaulax . Acanthogon -
yaulax . and Spiraulax with formula 6po, Ip, lant; and
Ceratium and Peridinium with formula 5po, Op, 2ant.
This corroborates the conclusions derived from a
study of the ventral areas, but emphasizes the fact
brought forth by the position of the posterior sulcal
plate that Goniodoma represents a short, independent
side branch, even though close to Ceratocorys . The
approximate similarity of the pattern of Goniodoma
with that of Peridinium and Ceratium must be consid-
ered a result of convergence, since the three equally
sized antapicals of Goniodoma present a fundamentally
different plan from that of Peridinium or Ceratium.

Table 2. Comparison of plate formulas of genera
treated in this report

Genera

Pl

ap

pr g

po

ant

Goniodoma 1

Ceratocorys 1

Gonyaulax 1

Acanthogonyaulax . 1

Spiraulax 1?

Peridinium 2

Ceratium 1

3 7 6 5 5

6 5

6 6-7
6 7
6 6

4 5-6
4 ?

The Epitheca

In considering the epitheca we have to deal with
both the number and the arrangement of the plates, as
in the case of the hypotheca. The total number of plates
in the genera investigated ranges from ten to sixteen,
and it shows no correlation with the grouping of the ge-
nera indicated by the other parts of the theca (see ta-
bles 1 and 2). In the other genera of the Peridiniales,
not included in this report, the number of epithecal
plates is also extremely variable, as is shown by the
above list of generic plate formulas (p. 3). When we
turn to the arrangement of these plates we find that
here, too, no generic grouping can be made which will
parallel that made on the basis of the hypotheca, girdle,
and ventral area. In fact, of the genera reported here,
no two have the same epithecal formula (table 2). It is
thus evident that the evolution of the epitheca has been
in many directions and that it has been decidedly inde-
pendent of the evolution of the other parts of the theca.

Summary

On the basis of the above comparisons of the vari-
ous parts of the peridinian skeleton, it is thus possible
to draw some conclusions regarding the relationships
of the genera studied and to postulate certain aspects of
the course of evolution in the group. When the term
"relationships" is used here, it is clearly understood
that the true relationship is not always indicated by
morphology. Results obtained in the field of genetics
have clearly demonstrated that the closest morphologi-
cal similarities do not always represent the closest re-
lationships. For the time being, however, we must
build our genetic discussion of the peridinians on the
assumption that morphological similarities express de-
grees of relationship, unless evidence clearly demon-
strates that the similarities are due to convereence.

10

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

The comparison of the morphological features of
the ventral areas of the forms in this report indicates
that Goniodoma is the most primitive genus investigat-
ed. This is shown by the simplicity of contours, size
equality, and small number of plates, viz., five, and by
the closed sulcal plate ring around the pore. At the
same time, the fact that the posterior sulcal plate is in
contact with the pore shows that Goniodoma does not
lie on the main line of descent but that it represents a
short, independent evolutionary branch near the base of
the general evolutionary path. Closely related to Goni -
odoma , but distinctly more advanced, and representing
a short, special side branch, is Ceratocorys , which has
the same number of sulcal plates. In this genus, how-
ever, the ventral area is narrowed, the sulcal ring is
broken, and the posterior sulcal plate is somewhat en-
larged. Still more advanced than Ceratocorys , and
closely related to each other, are Gonyaulax , Acantho -
gonyaulax , and Spiraulax, in which the ventral areas are
elongated and sigmoid, the posterior plate is greatly
expanded, and the number of plates has increased to six
or seven. Highly specialized and widely separated from
all the above genera and also from each other are Peri -
dinium and Ceratium . The ventral area of Peridinium
has a complex arrangement of intricate plates and lists,
whereas in Ceratium this structure is a wide, flat ex-

panse of hyaline plates.

The comparison of the girdle plates corroborates
the above conclusions, inasmuch as it separates the ge-
nera Peridinium and Ceratium from the others. At the
same time, it indicates that these two genera are mutu-
ally closer than either of them is to the remaining genera.

The comparison of the total number of hypothecal
plates shows an exact parallelism with that of the gir-
dle plates; there are seven in Peridinium and Ceratium
and eight in the others, thus again bringing Peridinium
and Ceratium together.

The patterns of the hypothecal plates separate
Goniodoma from Gonyaulax , Acanthogonyaulax . and
Spiraulax , showing, as is stressed above, that Gonio -
doma does not form a direct ancestral type.

The comparison of the epithecal plates does not
contribute to this picture, but rather indicates an inde-
pendent structural differentiation. No two of the genera
have the same epithecal formula.

Thus we are able to build up a plan of evolution and
relationships of the genera treated in this report, based
primarily on the ventral area and nicely corroborated
by the girdle and hypothecal tabulations (see fig. 2). As
more accurate knowledge is gained of the other genera
of the Peridiniales, it is hoped that these, too, will fit
into this general scheme.

FAMILY PERIDINIACEAE

11

SYSTEMATIC DESCRIPTION

As indicated on page 4 , the following families are
included in this paper: Peridiniaceae, Ceratocoryaceae,
Gonyaulacaceafe, Goniodomaceae, Ceratiaceae. The ar-
rangement of the families does not indicate relation-
ships, but rather expresses the degree to which the fam-
ilies have been studied; the first ones the most inten-
sively.

Family PERIDINIACEAE

Diagnosis . "Shape of the cell variable, spherical
to longish; small horns often on the hypotheca. Apex
present or absent. Girdle circular or somewhat spi-
raled; there are right and left spirals. Theca in 'youth'
quite thin, later usually developed into stronger theca
which falls apart into dissimilarly shaped polygonal
plates. Tabulation very different, variable, malforma-
tions even common. It is scarcely possible to set up
for Peridinium and its relatives, general valid plate
patterns; mostly there are 6-7 precingular plates, 5-6
postcingular, and 2 antapical plates which only in Dl-
plopsalis may be coalesced. The tabulation of the epi-
theca is more variable than the hypotheca. Surface of
the theca with areolae, papillae, spines, lists, or pores;
seldom smooth. Plasma of marine forms sometimes
colored. Stigmas in freshwater forms rare and little
considered, often pale. In marine forms pusules.
Chromatophores often in large numbers. Plasma inclu-
sions, starch, fatty substances, pyrenoids, rods (rhab-
dosomes). Nucleus roimdish to longish. Colony forma-
tion in one case. Formation of cysts after casting of
theca. Different icinds of reproduction. Length 18 mi-
crons to 300 microns. Fresh-, brackishwater, and ma-
rine." (Lindemann, 1928, p. 88.)

Three genera are established at present. They can
be differentiated in the following manner according to
Lindemann (1928, p. 88):

A. Only one of the antapical plates drawn out into a
short, hollow horn or spinelike point; shape + spin-
dle-shape Heterocapsa

B. Cell otherwise shaped

a. Shape at both poles more or less ellipsoidally
compressed; at the left margin of the longitudinal
furrow (on the hypotheca) is a conspicuous list
which can reach over to the antapex; antapical
plates two, rarely one Diplopsalis

b. Otherwise shaped, two antapical plates

Peridinium

Remarks . The above description and key clearly in-
dicate the insufficiency of our present knowledge. This
allows us to make neither a clear-cut definition of the
family Peridiniaceae as contrasted with the remaining
families, nor to establish generic diagnoses and descrip-
tions which will fit into the family description and at the
same time be exclusive and distinct. It should be empha-
sized that Lindemann (1928) was not at fault. His at-
tempt at classifying the Peridineae was remarkably suc-
cessful, considering the meager data at his disposal.
The only genus of the family treated in this report is
Peridinium.

Genus PERIDINIUM Ehrenberg
Diagnosis
See Lindemann, 1928, p. 89.
Description

Remarks . Because of our present hazy conception
of this genus, a redescription is necessary. The follow-
ing description is based solely on the representatives in
which the skeletal morphology has been worked out in
detail. It is intended to be but tentative and thus to be
filled in and rounded out as more material accumulates.
It must be stressed, however, that amendment should be
made only on the basis of material obtained by the com-
plete dissection of specimens and of material subjected
to a statistical analysis of form variation.

Dimensions . Among the forms in this report the
total length (1) varied from 44 microns in P. pallidum
to 275 microns in P. truncatum; the diameter (d) from
35 microns in P. pallidum to 200 microns in P. trunca-
tum. Many other forms ascribed to this genus are
smaller; e.g., P. faeroense is 16 microns in diameter.

Shape . All the forms treated in this report, except
P. pallidum, possess three well-developed horns, al-
though many other species ascribed to the genus are
hornless and some even spineless, and, in extreme
cases, completely spherical. Whether all these species
should be regarded as generically identical cannot be
decided at this time. The body is usually longer than
wide, but may be spherical, though rarely wider than
long. All the forms here treated are much longer than
wide, owing primarily to the long horns, the 1/d ratio
being as high as 1.5 in P. truncatum . The h/d ratio,
which expresses the length of the body exclusive of the
antapical horns (h) relative to the diameter, varies
from 0.53 in P. claudicanoides to 1.76 in P. depressum
var. tenellum . The angle which expresses the amount
of anteroposterior compression of the body a varies
from 78° in P. depressum to 139" in P. depressum var.
convexius .

Girdle . The girdle is more or less equatorial,
sometimes encircling the body in one plane, but usually
forming either a descending or an ascending spiral. Al-
though it is usually displaced, there is never any over-
hang. It seldom encircles the body at right angles to
the longitudinal axis, but is deflected from this position;
in the forms treated herein, this deflection is from 10°
to 15°. The girdle may or may not be excavated.

Sulcus . The sulcus is a groove on the ventral side
of the body extending from the ends of the girdle, or
from somewhat anterior to them, to the antapex of the
body. In it lies the flagellar pore. The pore is usually
oval in shape and the theca of the sulcus is so con-
structed that the pore opens laterally instead of directly
ventrally. The plate complex of the sulcus may spread
out to some extent, forming a wide ventral area with the
sulcus proper located within it.

Plate pattern . If the broad generic concept of
Lindemann (1928) is accepted, there are a great number
of plate patterns represented in the members of Peri -
dinium . This is particularly true of the epitheca. The

12

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

only constancy in the entire pattern in Peridinium s. 1.
is the absence of posterior intercalaries and the pres-
ence of two antapicals. For abbreviations of the names
of the plates, see above, p. 3.

In the forms treated in this report the pattern of the
major body plates is as follows:

4ap (5 in P. depressum f. multitabulatum n.f.);

3a (2 in P. depressum f. bisintercalares and P. oceani-

cum f. bisintercalares n.f.);
7pr (8 in P. depressum f. multitabulatum n.f.);
4g; 5po; Op; 2ant.

The four girdle plates are of unequal length. The
third is the longest, comprising all the dorsal and later-
al sides of the girdle and, in P. p allidum , most of the
ventral side also. The other three lie ventrally and are
comparatively small. The girdle plates may be very
significant in the classification of the genus, the number
being of generic value, and the pattern subgeneric. The
determination of the girdle plates has too often been
neglected in analysis of the thecal pattern, in spite of
the fact that their dissection is not difficult.

The epitheca of Peridinium is in an unstable condi-
tion, as will be pointed out later. In all species dissect-
ed, however, there was found an apical ring platelet and
a ventral apical platelet. No variation was found in the
number of girdle plates nor in the hypotheca except in
P. oceanicum f. tricornutum n.f.

Probably the most important region of the theca to
be investigated at the present time is the ventral area
or sulcal region. This is a very complex area made up
of several plates. The necessity of dissection in deter-
mining these structures has retarded our knowledge of
them. Kofoid (1909) reported on this region in P. steinii,
but it is not certain that complete dissections were made
and his analysis must be verified before being accepted
into the general concept of the ventral area of Peridini -
um . Faure-Fremiet and Puigeandeau (1922) indicated
plates in the ventral area of several species of Peridini-
um including P. oblongum and P. crassipes . They show
seven plates. These must have been drawn from the
authors' imagination, as they bear no relation whatever
to the actual tabulation of these species. The same may
be said for the sutures shown encircling the antapical
horns (fig. 9). The only detailed analysis of this area in
the genus so far published which is at all acceptable, is
that of Abe (1936) for Peridinium ovatum and related
forms. These analyses can be incorporated into the
general scheme developed from our own several analy-
ses in widely separate representatives of the genus.

Certain features of the plate pattern of the ventral
area in the genus Peridinium are conservative; others
vary from species to species. The number of plates is
not constant in the genus, but varies from five to six;
different plates may be wanting. The conservative ele-
ments are represented by four plates: an anterior , a
posterior , a right, and a left sulcal plate. These plates
are conservative in that they are always present and
always have the same relation to each other and to the
flagellar pore. They do vary considerably in shape,
however, in the different species. The anterior sulcal
plate occupies the area between the ends of the girdle
and joins the posterior end of the first apical; it extends
to the anterior edge of the flagellar pore. The posterior
plate is a very complex structure, the most complex
plate so far found in the peridinian skeleton. Its shape
is roughly that of a U in which one limb has been rotat-

ed so that its axis lies at right angles to that of the
other. The curve of the U is narrow, and the limbs are
expanded into wide areas. The details of the shape will
be described under each species. The right plate is the
largest of the ventral area and forms the right edge of
the flagellar pore. It extends from the anterior to the
posterior sulcal plate. It bears a prominent list on its
left margin, the right accessory sulcal list, which over-
lies the pore and may bear processes which project into
the protoplast. This plate is a prominent element of the
ventral area in undissected specimens. The left sulcal
plate is deeply set in the sulcus and is not clearly seen
without proper cleaning or dissecting of the specimen.
It is, however, fairly large and forms the left side of
the ventral area and the left edge of the flagellar pore.
It is one of the most constant elements of the area and
varies but little from species to species. In addition to
these four principal plates, the ventral area may have
three other plates, although all of these never occur
simultaneously. They are: the right accessor y sulcal
plate , the posterior accessor y sulcal plate , and the right
internal sulcal plate . The right accessory sulcal plate
lies against the distal end of the girdle. It was found
only in P. p allidum and it represents simply the anteri-
or end of the left sulcal plate in other forms. The pos-
terior accessor y sulcal plate lies between the right and
the left and the posterior sulcal plates, thus forming
part of the posterior margin of the pore. It occurs in
all the species, and is comparatively large in P. trunca -
tum (24 microns long) and extremely minute (about 2
microns long) in the other species investigated. The
right internal sulcal p late is a part of the complex inter-
nal skeleton on the inner side of the right sulcal plate.
It was found only in P. crassipes and P. depressum.

The apex of the theca is quite complex, with the
same general structure throughout all the species inves-
tigated. Only three of the four apical plates actually ex-
tend to the apex; the first is subtended by a narrow
plate, the ventral apical platelet. The apical ends of this
and of the second to fourth apical plates are joined to-
gether around the apical pore platelet , which is a ring
embedded in the apex.

Structure of thecal wall . Little is known of the de-
tailed structure of the thecal wall. It is quite thick in
all the species investigated. Its exact thickness is dif-
ficult to determine, but it is probably 1 to 2 microns in
the thinner parts and considerably more in the thicker
parts. The surface is variously marked with reticula-
tions or tubercles. All the species are porulate at least
in the larger plates; sometimes some of the sulcal
plates are entirely smooth.

In the species investigated, all plates are fastened
together by rabbet joints, as has been shown for other
species by Peters (1928). This joint is constructed as
follows: Along each suture of the theca there is attached
to one of the two adjoining plates a strengthening mem-
brane which underlaps the adjacent plate, forming a
rabbet joint (fig. 3A). Thus there are an external and
and internal suture separated from each other by the
width of the membrane. These membranes are an inte-
gral part of the plate to which they are attached and can-
not be detached from it. They occur whether or not there
is an intercalary zone. When such a zone is present,
the external suture divides it approximately in the mid-
dle, so that when the two plates are separated, half of
the zone remains attached to the plate without the mem-
brane and half to the plate with the membrane. Since

FAMILY PERIDINIACEAE

13

the rabbeting membrane is apparently of the same
width in specimens with and without intercalary zones,
there must be some intercalated material at the inter-
nal suture as well as at the external suture, as shown in
figure 3B. If this be true, then there is an internal as
well as an external intercalary zone with the internal
suture bisecting it approximately in the middle.

Lists . Although never developed to the extreme de-
gree that they are in some members of the Dinophysi-
ales, nevertheless, lists form a prominent part of the
thecal morphology of Peridinium . The girdle lists are
always well developed and the posterior girdle list is
usually confluent with the sulcal lists. The ventral area
has a complex system of lists. This area is usually en-
closed by the right, posterior, and left sulcal lists, and
internal to these there may be right, posterior, and left
accessory sulcal lists. These will be described under
each species. The apex is another region of complexi-
ty as regards lists. It is encircled by a list made up of
parts of three lists attached to the apical plates. These
lists always extend down the ventral side of the body as
far as the posterior end of the ventral apical platelet,
but may extend down the ventral and lateral sides of the
body part way or entirely to the girdle. These will be
described in detail in the individual species descriptions.
No prominent body lists are developed except along
plate sutures. The transverse ridges across the girdle
sometimes, however, take on the character of lists.

Spines . Antapical spines are developed in some
species (e.g. P. pallidum ) in place of antapical horns.
No other spines occur. The "apical spines" and the
"antapical spines," internal to the antapical horns
sometimes indicated in published figures, are not spines
at all but are optical effects produced by the curvature
of lists.

Historical Review

Peridinium is the largest and probably the most
widespread genus of the Peridineae. More than two hun-
dred species have been described. Thirty-eight of these
are fresh-water forms, the rest are marine.

There are many morphological characters in addi-
tion to the general body shape which can be used in de-
fining the species. Unfortunately, however, these char-
acters are variable. Because of the pronounced intra-
and interspecific plasticity, the genus is the most diffi-
cult in the Peridineae from the standpoint of thesystem-
atist. So far no one has had the courage to attempt a
generic monograph, a fact which is fortunate since it
would, necessarily, have been only an abortive attempt
because of our ignorance in regard to the pertinent data.
Such a treatment can be made only after we have ac-
quired a thorough knowledge of the thecal morphology of
each of the species.

Furthermore, the generic concept is one of the
vaguest in the Peridineae. It has been very changeable,
being sometimes narrow, sometimes broad. For exam-
ple, Lindemann's concept (1928) of the genus included
four described genera besides Peridinium of previous
authors. Generally speaking, the confusion in the genus
progressed as the number of described forms increased.
It is fair to predict, however, that, when all the mem-
bers of this vast genus have been thoroughly analyzed, a
satisfactory classification will be evolved in spite of the
variation in some features which now baffle our attempts.

The first grouping of the species of Peridinium was

made by Gran (1902). He divided the genus into two
subgenera: Protoperidinium and Euperidinium . Proto -
peridinium was adopted by Gran fromBergh (1881), who
applied this name to a group of species to which he as-
signed generic value. The name Euperidinium , on the
other hand, was introduced by Gran. Protoperidinium .
according to Gran, is characterized by solid antapical
spines and by a right-handed girdle, i.e., on the ventral
side of the body the right (distal) end of the girdle is
located anteriorly to the left (proximal) end. Euperi -
dinium is characterized by hollow antapical horns and
by a left-handed girdle, i.e., the left end of the girdle is
displaced anteriorly. Gran listed the following species:
Protoperidinium : P. p ellucidum Bergh s.L, P. ovatum
Pouchet, P. decipiens Jorg., P. steinii Jorg., P. globulus
Stein, Euperidinium : P. conicus Gran, P. pentagonum
Gran, P. divergens Ehr. s.s., P. depressum Bail. s.L

This classification was satisfactory for the few
species that were known at that time and was accepted
by many authors. Later investigators, however, re-
vealed forms which could not be classified on the basis
of these criteria. For instance, forms were found with
a left-handed girdle, but with solid antapical horns.
Furthermore, forms with no definite displacement of
the girdle in either direction were discovered.

Paulsen (1908) used Gran's classification in the
treatment of thirty-nine species of Peridinium although
he was compelled to acknowledge exceptions to the sys-
tem. Thus, in Protoperidinium he included two species,
P. findlandicum Paulsen and P. granii Ostenfeld, which
have hollow horns. Those forms in which there is no
displacement of the girdle he placed in Euperidinium .
The description of this subgenus was further qualified
by the statement that there are usually hollow horns.
Paulsen was the first to show discrepancies in theGran-
ian classification.

Broch (1910) noted the inadequacy of the classifica-
tion based on the displacement of the girdle and the struc-
ture of the antapical horns. He also pointed out that the
arrangement of the plates of the theca afforded a ready
diagnostic means. Although he grouped his ten species
from Val di Bora under the subgenera Protoperidinium
and Euperidinium , he carefully described under each
species the conformation of the first apical plate and
figured the plate pattern for each form.

Finally, Jorgensen (1913) made a comprehensive
reclassification of the genus on the basis of the plate
pattern, using the number of plates that border the first
apical as a primary character in the formation of sub-
genera and the pattern of the dorsal plates as the cri-
terion for the division of the subgenera into sections.

Jorgensen divided the genus Peridinium into two
subgenera, Orthoperidinium and Metaperidinium . and
discarded the subgeneric names used by Gran. Ortho -
peridinium is characterized by a first apical which
touches only four of the major plates of the epitheca; the
second apical and first precingular are on the left side,
the fourth apical and seventh precingular on the right
side (fig. 4A). Metaperidinium is characterized by a
first apical plate which borders five or six of the prin-
cipal plates of the epitheca; the second apical and the
first and second precingulars are on the left side, the
fourth apical and the seventh, or the sixth and seventh,
precingular on the right side (fig. 4B, C).

Orthoperidinium was divided into three sections,
principally on the basis of the dorsal epithecal plates,
as follows:

14

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PEREDINIALES

Tabulata, in which the second anterior intercalary
borders the third and fourth or the fourth and fifth pre-
cingular plates (fig. 5C).

Conica . in which the second anterior intercalary
touches the third, fourth, and fifth precingulars (fig. 5B).

Oceanica . in which the second intercalary touches
only the fourth precingular (fig. 5A).

Metaperidinium was divided into four sections, as
follows:

Pyriformia , in which the second anterior intercalary
plate touches two precingular plates, as in section Ta -
bulata of Orthoperidinium (fig. 5C).

Paraperidinium , in which the second intercalary bor-
ders the third, fourth, and fifth precingulars (fig. 5B);
the first apical plate is bounded by six of the major
plates of the epitheca (fig. 4C): the second apical and
first and second precingulars on the left side, the fourth
apical and sixth and seventh precingulars on the right
side. Jorgensen did not give this group subgeneric rank
because there was considerable variation in the length
of the suture between the first apical and sixth precin-
gular plates; the suture is sometimes quite short.

Humilia . in which the second intercalary touches only
the fourth precingular (fig. 5A); with solid antapical
horns.
Divergens , as Humilia but with hollow antapical horns.

Jorgensen thus established not less than seven cat-
egories for the grouping of the species of Peridinium .
The number had thus become greater than when Gran
devised his simple classification, and it demanded a
more rigorous examination of the material.

Although the thecal plates in Peridinium were
known by Jorgensen to present several patterns, the
number of plates in the theca was considered by him to
be constant. He (1913) described the genus as having
three anterior intercalary plates. Forms which had
only two intercalaries and which had been included in
Peridinium by others he placed in a new genus, Archae-
peridinium (fig. 6B).

Jorgensen's comprehensive classification of the Pe-
ridinium species on the basis of the plate pattern laid
the foundation for a clearer understanding of the com-
position of, and the relationships within, the genus than
had ever before been possible. It promised to end the
taxonomic difficulties which this genus presented. His
classification was accepted by practically all later
workers up to the present time and has been extremely
helpful.

As is shown in this paper, however, even this sys-
tem is not adequate for the proper classification of the
great number of variants which occur.

Paulsen (1931) revised the system of Jorgensen
(see also Peters, 1928, and Dangeard, 1927). He con-
sidered the classification of Jorgensen unnatural, and
proposed a system in which not only the plate pattern, .
but a combination of plate pattern and other characters
was used. He abolished the subgenera of Jorgensen but
retained the sections with some revision.

Paulsen (1931) referred to JOrgensen's Archaeperi -
dinium as a subgenus of Peridinium , as had been done
by Lebour (1925) and others. This subgenus is charac-
terized by having only two anterior intercalary plates.

The second subgenus, with three intercalary plates,
Paulsen called Veroperidinium . This is equivalent to
the subgenus Peridinium proper of Leboiir.

Paulsen divided the subgenus Archaeperidinium into
two sections:

Avellana , in which the two intercalaries are equal.

Excentrica , in which the two intercalaries are very un-
equal.

The subgenus Veroperidinium he divided into eight
sections, seven of which corresponded roughly to the
sections of JOrgensen. The eighth section, Paradiver -
gentia, was new. A summary of his sections of Vero -
peridinium follows. In describing the relation of the
dorsal plates he used the terms "quadra," "penta,"and
"hexa" to designate the number of sides on the second
anterior intercalary, and "ortho," "meta," and "para"
to designate a four, five, or six-sided first apical.

Pellucida : Para hexa, rarely para penta or quadra or
meta hexa. Right-handed. Without antapical horns; has
two, or more frequently three, antapical spines. This
section corresponds to Paraperidinium of Jorgensen.

Humilia : Meta quadra. Right-handed, without horns,
but often with two antapical spines.

P yriformia : Meta penta, rarely quadra or hexa. Right-
handed, without antapical horns, but in general has two
antapical spines.

Tabulata : Ortho penta or hexa or quadra. Left-handed
or with circular girdle. Cell round, without horns or
spines, or with slight spines.

Paradivergentia : Para quadra or hexa. Right-handed
or with circular girdle; with two hollow antapical horns.

Divergentia (=Divergens Jorgensen): Meta quadra,
rarely penta. Girdle circular or right-handed; with two
hollow antapical horns.

Oceanica : Ortho quadra, rarely penta or hexa (or even
para). Left-handed. Girdle oblique relative to the lon-
gitudinal axis of the body. Epitheca narrows into an ap-
ical horn; two hollow antapical horns.

Conica: Ortho hexa, more rarely penta or quadra.
Girdle circular or left-handed. Body square or rhom-
boid in ventral view, without apical horn but usually
with two hollow antapical horns.

Paulsen's classification is an improvement over
Jorgensen's (1913), for it takes into consideration the
occurrence of a greater number of combinations of char-
acters. In so doing, however, Paulsen acknowledged the
occurrence of a greater number of variations in the
characters which have been used as fundamental taxo-
nomic units.

All the classifications devised so far have been
based on a certain stability of the plate pattei-n within
the species, particularly in the region of the first apical
plate and the dorsal epithecal plates. Furthermore, all
are based on the presence of three anterior intercalary
plates in Peridinium proper. As is shown below, in the
present investigations, forms in the section Oceanica
have been found with only two intercalary plates.

It should finally be noted that should a subgeneric
classification be re-established for the sections, this
must be done with due consideration to the international
rules of nomenclature. When a new classification is
proposed, there is no justification for the introduction
of completely new terms. Old names must be retained,
with only the termination changing if they are given al-
tered rank (International Rules of Botanical Nomencla-
ture, 1935, art. 51). These rules were completely disre-
garded by JOrgensen and Paulsen. Thus Gran's subgenus
Protoperidinlum. for Instance, has not been perpetuated.

FAMILY PERIDINIACEAE

15

Methods of Study

Selection of material . Since it would have been an
insurmountable task to treat a really representative
number of species of this large genus, a compromise
plan of study had to be devised. For the sake of render-
ing an initial contribution to the exact knowledge of the
thecal morphology of Peridinium , representatives from
each of the major groups of the genus were selected for
detailed dissection, viz., P. depressum from Orthoperi-
dinium . P. crassipes and P. truncatum from Metaperi -
dinium, and P. pallidum from Paraperidinium . The re-
sults of these investigations give some information a-
bout both the generic unity and the interrelationships of
the lower than generic groups.

In addition to these detailed dissection studies, a
statistical analysis was made of Peridinium depressum
and of its relatives comprising the Formenkreis Peri -
dinium depressum of Broch (1906). This work was un-
dertaken in order to establish a method of attack on a
very variable group. Thus, these studies have a three-
fold purpose: first, to acquire a knowledge of skeletal
mo-phology; second, to learn something of specific in-
terrelationships and generic unity; third, to inquire into
the nature of specific variability, a feature of exception-
al significance in this group.

Measurements . In determining the size and in com-
puting ratios expressive of the shape of the Peridinium
body, certain measurements were used. Measurements
made with the specimen presenting the ventral face
(p. 1) are indicated schematically by figure 7. Desig-
nations of dimensions in that figure are as follows: a,
length of right antapical horn, considering the base of
the horn as a curved continuation of the lateral body
contour running to the base of the right side of the sul-
cus; b, thickness of the right antapical horn measured
midway between its base and apex; d, diameter of the
body at the girdle; h, distance between the end of the ap-
ical horn and the base of the right side of the sulcus; J,
total length, or distance between the ends of the apical
and right antapical horns; a, the angle representing the
degree of convexity of the lateral profile. The angle oc
is constructed with its vertex in the girdle at the right
edge of the body, and with its sides intersecting the body
walls at points at a distance from the vertex equal to
one-fourth of d.

Measurements made with the specimen presenting
the apical view are indicated schematically by figure 8.
Designations of dimensions in that figure are as follows:
g, dorsoventral diameter measured through the mid-
body; r, in some species, e.g., P. truncatum . it is nec-
essary to measure the prolongation of the ventrolateral
limbs of the body in the equatorial region. The value r
is obtained as follows: Construct a line passing through
the apex (b) and the farthest point on the right limb (a).
On this line erect a perpendicular at point c. The point
c is determined by its distance from a which equals one-
third g. The thickness of the limb, r, is measured along
this perpendicular.

Various features of the body shape can be expressed
by the dimensional proportions. The best reference for
most of these ratios is the diameter (d). It can be meas-
ured in either the ventral or the apical view and is in it-
self a good standard for the absolute size of the speci-
men.

The general body form can be expressed by the

angle a and the ratio of the length to the diameter of the
body. In computing the latter ratio, h, was frequently
used instead of, or in addition to, i because a slight
displacement of the specimen sometimes caused more
error in l_ than in h on account of the divergence of the
right antapical horn in some forms. The distance h
does not include the antapical horn, which has a tenden-
cy to vary more than the apical horn, so that the value
h/d gives a more accurate criterion of the length of the
body than does the ratio _l/d.

In expressing the relative length of the antapical
horns, it is usually necessary to measure only one of
these structures, as the variation is usually proportion-
al. In this work the length of the right horn was meas-
ured, as it usually presents a truer value because of its
lesser degree of inclination in the ventral view. The
length relative to the diameter of the cell, a/d, was then
computed. For the relative thickness of the antapical
horns the ratio b/a, the thickness of the right antapical
horn in relation to its length, was computed.

Where the shape of the body in apical view was im-
portant, the g/d ratio was computed. The thickness of
the lateral limbs in apical view was found to be best ex-
pressed by the ratio r/g.

The width of the girdle was always measured and
many smaller measurements referred to this.

Peridinium depressum Bailey and related forms

Introductor y remarks . Broch (1906) designated as
the "Formenkreis Peridinium depressum Bailev" a
group of highly variable and intergrading forms closely
related to P. depressum Bailey. This species is an
Orthoperidinium with a four-sided second anterior in-
tercalary plate. The members of the group present one
of the most difficult taxonomic problems of the Peridi-
neae. They have been studied by several investigators,
whose results have been at variance and decidedly con-
fusing. Because of this fact, and since the Carnegie col-
lection was rich in these forms, this group was subject-
ed to an intensive analysis in order not only to solve the
problems of this particular group, but also to formulate
methods and concepts which might be applied to the ge-
nus as a whole or to other groups of the Peridineae
which present a series of variable and intergrading u-
nits.

Diagnosis . The group as conceived in this report
includes all the species of Orthoperidinium in which the
plane of the girdle is inclined to the longitudinal axis.
All these species are confined to Jorgensen's section
Oceanica . They are, indeed, the only forms now known
in the entire genus with a strongly inclined girdle, ex-
cept P. amplum Matzenauer. In the latter species, how-
ever, the apical and antapical horns do not lie in the
same plane, a feature characteristic of the "Formen-
kreis." The species in this group are mostly large, u-
sually with prominent horns, and the girdle is left-hand-
ed.

Extent of the group . The following forms have been
described in the literature:

P. depressum Bailey (1855)

P. depressum f. brevisulcatum Dangeard (1927a)

P. parallelum Broch (1906)

P. saltans Meunier (1910)

P. antarcticum Schimper (Karsten, 1905)

16

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

P. claudicans Paulsen (1907)

P. polymorphum Lindemann (1924)

P. oceanicum VanhOffen (1897a, 1897b)

P. oceanicum f. arupinense Broch (1910b)

P. oceanicum var. parvulum Mangin (1913)

P. oblongum Aurivillius (1893)

P. oblongum var. symmetricum Dangeard (1927a)

P. oblongum var. inaequale Dangeard (1927a)

P. oblonecum var. iatidorsale Dangeard (1927a)

P. obliquum Dangeard (1927a)

P. murrayi Kofoid (1907)

P. murrayi var. occidentals Pavillard (1931)

P. murrayi var. orientale Matzenauer (1933)

In the present report only those forms occurring in
the Carnegie collection are treated. They are:

P. depressum Bailey

P. depressum var. parallelum Broch

P. depressum var. rectius n.var.

P. depressum var. convexius n.var.

P. depressum f. bisintercalares n.f.

P. depressum f. multitabulatum n.f.

P. claudicanoides n^sp.

P. oceanicum Vanhoffen

P. oceanicum var. tenellum n.var.

P. oceanicum f. spiniferum n.f.

P. oceanicum f. bisintercalares n.f.

P. oceanicum f. tricornutum n.f.

Methods of stud y. The first well-considered clas-
sification of the Peridlnium depressum group was based
on the principles outlined by Jorgensen (1913) for the ge-
nus as a whole. This classification presupposes a sta-
bility In the number and arrangement of the major plates
of the theca. The inadequacy of the last assumption
when applied to the Peridinium depressum group will be
clear from the following historical review and consider-
ation.

Jorgensen (1913) described the genus Peridinium as
having the following pattern: 4ap, 3a, 7pr, 5po, 2ant.
Lebour (1925) and Paulsen (1931) broadened the concept
of the genus. They included JOrgensen's Archaeperidi -
nium, which has only two intercalary plates, and divided
the genus into two subgenera: Peridinium with three,
Archaeperidinium with two intercalary plates. In the
present investigations, forms in the section Oceanica of
the subgenus Peridinium were found with only two inter-
calary plates (pp. 21, 24); and Dangeard (1927b) report-
ed a variety with only one intercalary (see next para-
graph). Thus, this subgeneric character has been shown
invalid.

From the Peridinium depressum group the follow-
ing examples of plate variation may be given. Barrows
(1918) described a specimen of P. oceanicum . which is
closely related to P. depressum . with the ventral epithe-
cal plates of the Paraperidinium type. Dangeard (1927b)
described what he called a variety of P. depressum with
the ventral epithecal plates of Paraperidinium and the
dorsal plates of the section Pyriformia . Considering
the body form and the Inclined girdle of this specimen,
along with its plate pattern, it is either a distinct vari-
ety or a species, unquestionably belonging to the group
related to P. depressum . Dangeard (1927b) also de-
scribed some aberrent plate patterns in P. oblongum .
These variants he designated as varieties, as follows:
var. symmetricum . with the usual dorsal epithecal pat-
tern of the section Oceanica ; var. inaequale, with the
pattern of the section Tabulata ; and var. Iatidorsale .
with only one intercalary plate (subgeneric character).
This single intercalary plate borders plates 2pr, 3pr,

4pr, and 5pr according to his figure. In his table (p. 11)
he states that it also borders plate 6pr.

Barrows (1918) was of the opinion that there are
only four unstable areas in the theca of Peridinium .
Variation, he maintained, occurs only in the areas at the
two sides of the first apical, and at the sides of the sec-
ond intercalary along with the adjacent plates involved
in any pattern. Other variable areas, however, were
found later. Peters (1928) described two patterns in P.
depressum in regard to the epithecal plates.

The variation on the lateral sides of the epitheca in-
volves plates 2ap, 2pr, la, and 3pr on the left side and
4ap, 6pr, 3a, and 5pr on the right side (fig. 9). The var-
ious patterns will be referred to in the pages to follow
as the first and second symmetricalj and the first and
second asymmetrical patterns. In the first symmetri -
cal pattern . 2ap touches 3pr, and 4ap touches 5pr (fig.
9A). In the second symmetrical p attern . 2pr touches la,
and 6pr touches 3a (fig. 9B). In the first asymmetrical
pattern . 2pr touches la but 4ap touches 5pr (fig. 9C). In
the second asymmetrical pattern . 2ap touches 3pr but
6pr touches 3a ^fig. 9D).

Peters (1928) reports all four of these patterns in
P. depressum . Lindemann's (1925, figs. 10, 11) figures
of P. marinum (=P. depressum ) show the first symmet-
rical and the first asymmetrical patterns. In the Car -
negie material they were not all found in the same spe-
cies. In P. depressum the first symmetrical and first
and second asymmetrical were found; in P. oceanicum
the first symmetrical and first asymmetrical; in P.
claudicanoides the second symmetrical and first asym-
metrical.

These patterns are not stable features of the theca.
The length of the critical sutures between the four plates
in question on each side of the shell varies. In species
where more than one pattern occur, there is an inter-
gradation of the different patterns. Specimens occur in
which the edges of the four plates meet at a common
point, representing an intergrade between two patterns.
Lebour (1925, pi. 23d) shows this condition on both sides
of the theca, but this may be an error in drawing. Pe-
ters (1928) found the common intersection on each side
of the theca in different specimens. In the Carnegie ma-
terial this condition was found only in P. depressum and
only on the left side (fig. 9E). These observations upset
Barrow's contention that the edges of four plates never
meet in a common point and that an intergradation never
occurs between two alternate plate patterns (1918, pp.
453, 455).

In order to study this intergradation and present it
graphically, measurements were made of the critical
sutures in species in which the first symmetrical and
first asymmetrical patterns occur. The following com-
putation was made: The length of the critical suture on
the left side was divided by the length of the critical su-
ture on the right side and the quotient called the x- ratio .
In the symmetrical pattern the ratio was considered a
positive quantity and in the asymmetrical a negative
quantity. Obviously, in the case of the intergrade pat-
tern (fig. 9E) the ratio was zero.

The x-ratio was computed for 144 specimens of P.
depressum. P. oceanicum , and varieties selected at ran-
dom. The ratios were grouped into 0.10 unit classes and
the frequency of the classes plotted (fig. 10). It is evident
that in the Carnegie material the symmetrical was the com-
moner pattern, occurring in about 87 per cent of the
specimens. The commonest x-ratios were from +0.5 to

FAMILY PERmmiACEAE

17

+ 1.0. Two intergrades were found in these random sam-
plings, represented by the two specimens with x- ratios
of 0.0. In the symmetrical pattern the critical suture on
the left side varied from to 1.6 times as long as the
one on the right side; in the asymmetrical pattern the
alternate suture varied from to 0.9 times the one on
the right side.

These observations show definitely that p late pat -
tern in this group of species is not a stable feature but
that there is a variation both in the length of the sutures
and in the relative position of the plates, and that be-
tween two patterns there is a continuous line of inter-
grades.

Thus, it is evident that the epithecal plate pattern
alone cannot be used for the classification of the species
related to P. depressum and that it must be used with
considerable discretion in other parts of the genus as well.

The hypothecal pattern is constant throughout the
genus, so that it, too, cannot be used. In the present in-
vestigations the tabulation of the ventral area was stud-
ied. Although it differs greatly in different parts of the
genus, it was found to be identical throughout the "For-
menkreis P. depressum ." Thus, the plate pattern of no
part of the theca is of any value in classifying the units
of the group now under consideration.

For this reason, a new method had to be devised for
this purpose. In order to determine whether or not spe-
cific and varietal segregations can be made on the basis
of body shape, the material in the Carnegie collection
related to P. depressum was studied from this stand-
point. The results showed that the "Formenkreis P. de-
pressum" is made up of several units, some of specific
value, others of varietal, and that these are expressed
by the shape of the body.

In order to make proper segregations on the basis
of body shape, it is necessary that this feature be de-
scribed by numerical expressions so that the frequency
of variations can be plotted. In order that the accumu-
lated information of the various workers may be com-
parable, these numerical expressions must be of a stand-
ard nature. For instance, the conclusions in the present
work stand partly in opposition to those arrived at by
Peters (1928). Even though this is in most part due to
the different material used, it is probably also due to the
different methods employed in measuring the body pro-
portions. For this reason, the proposed standard meth-
ods for orienting and measuring the specimen described
above (pp. 1, 2, 13) were used in this work.

When numerical expressions are used, a large num-
ber of specimens can be measured, the body proportions
computed, the values grouped into convenient classes,
and the frequency of these classes plotted. In the inter-
pretation of the frequency diagrams, it is necessary to
have in mind a standard expression of the species con-
cept. The following definitions of the various units have
been used in this report.

It is assumed that a species represents a group of
h.uividuals which is morphologically distinct or nearly
so in one or more features. The presence of inter-
grades in a very small proportion of the specimens is
not considered to vitiate the specific segregation. Var-
ieties may be considered incipient species which also
have a certain morphological distinctness but which are

connected with the main species by a higher proportion
of intergrades. Forms are considered as temporary
expressions due either to internal or to environmental
causes. They are characterized by rarity of occur-
rence. These are the main concepts which have been
used in the classification of the Carnegie material given
below.

Example of application of method . The first prob-
lem in the "Formenkreis" to be attacked by the statis-
tical method was the determination of the validity of P.
oceanicum VanhOffen as a specific unit.

Vanhoffen (1897a) figured P. oceanicum as a spe-
cies similar to P. depressum but longer and more slen-
der. This was accepted as a valid species by most au-
thors. Peters (1928), the only previous investigator to
make a numerical study of the body proportions in this
group, took exception to this. On the basis of antarctic
material and of one sample of North Sea material, he
concluded that P. oceanicum represents simply one end
of a line of variation which includes both P. depressum
and P. oceanicum . although he recognized "broad ' and
"slender" forms.

In the present investigations 170 random specimens
of the "Formenkreis" from widely scattered Carnegie
stations in the North Atlantic were measured and the
h/d ratios computed. The frequencies of the length,
width, and h/d classes were plotted as shown in figures
11-13. As is apparent from figure 11, this group of
specimens was homogeneous so far as length was con-
cerned. Some length classes were somewhat more com-
mon than others, but they were all connected by numer-
ous intergrades. There was no indication of separated
variation groups. Similar results were obtained in a
study of the frequency of the diameter classes (fig. 12).
This indicated an even more unified group except for the
small group at the 70-micron and 75-micron classes,
which further observation of the material failed to jus-
tify as a distinct, unit.

The diagram of the plotted frequencies of the h/d
ratios, however, indicated two variation groups (fig. 13).
One centered about the 0.90-unit class, the other around
1.35. The extremes of the first group ranged from 0.65
to 1.20 and of the second group from 1.20 to 1.75.

We have here a basis for assigning specific values
to two forms: a broad form, P. depressum . in which the
h/d ratio is less than 1.20; and a slender form, P. oce -
anicum , in which that ratio is more than 1.20. Any spec-
imen with an h/d ratio of about 1.20 must be considered
a transitional form between the two species. One such
was found in the above samplings, as indicated in the
diagram. It must also be concluded, therefore, on the
basis of the above studies, that these two species are
very close. Indeed, more extended studies of other ma-
terial may bring them closer than is indicated by the
above data.

It is clear from these studies, however, that we are
not dealing here with a single homogeneous group, and
that P. oceanicum does not represent simply one end of
a line which Includes both P. depressum and P. oceani -
cum . as Peters (1928) contended.

The further application of this statistical method in
this group will be taken up in the discussions under the
particular species.

18

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

Peridinium depressum Bailey
(Figure 14)

Peridinium depressum Bailey, 1855, pp. 12-13, pi.

figs. 33, 34. Jorgensen, 1899, p. 36, tabs. 4, 18, 30,
44, 58, 72. Ostenfeld, 1900, p. 57, tabs. 2-7. Cleve,
1900b, p. 257. Jorgensen, 1901, p. 34. Gran, 1902,
pp. 186, 191-192. Jorgensen, 1905, p. 109. Van
Breeman, 1905, p. 43. Broch, 1906, pp. 151-157,
fig. 1. Paulsen, 1907, pp. 11, 15. 1908, pp. 39, 53,
fig. 67. Broch, 1908, p. 5. 1910, pp. 51-52, fig. 26.
Meunler, 1910, p. 27. Paulsen, 1913, pp. 276-279,
pi. 46. Mangin, 1913, pp. 158-160, 162-164,166-
169, 171, 177-178, 180, 187, 220-222, fig. 9, tabs.
1-3. Jorgensen, 1913, pp. 5-6. Forte, 1922, pp. 89,
188, 207. Lebour, 1925, p. 119, pi. 23, figs. a-f.
Dangeard, 1926, p. 322, fig. 10. Dangeard, 1927b,
p. 2, figs. lA-lC. Paulsen, 1930, pp. 55, 68. Pavil-
lard, 1931, pp. 55, 64-65, 111-112, 114-115, 121,
123, 125, 127, 129, 131, 133, 137, 157, 159, 161,165,
169, 173, 177, 183, 185, 191, pi. 2, figs. 6A-6E.
Gran, 1933, pp. 162, 180.

? Peridinium divergens y renifqrme Ehrenberg, 1854,
p. 240. Meunier, 1910, p. 23, pi. 1, figs. 1-4.

Ceratium divergens Claparede and Lachmann, 1861, p.
71, pi. 13, fig. 23.

Peridinium divergens . Bergh, 1881, pp. 63, 67, 70, 73.
Bergh, 1882, pi. 15, fig. 45. ? Stein, 1883, pi. 11,
figs. 1, 2. Vanhoffen, 1897a, pp. 267-268, pi. 5, fig.

1. Cleve, 1900a, figs. 15, 16. Meunier, 1910, pi. 2,
figs. 45, 46. Lebour, 1917, p. 186. Meunier, 1919,
pp. 12-14, pi. 15, figs. 1-5.

Peridinium divergens vari^te, Pouchet, 1883, p. 40, pis.

20, 21, fig. 23.
Peridinium divergens var. reniforme , Pouchet, 1883, p.

40, pis. 20, 21, figs. 24-27.
not Peridinium divergens var. typus . Pouchet, 1883, p.

38, pis. 20, 21, figs. 20, 21. Ostenfeld, 1899, p. 60,

84, tabs. 1-8.
Peridinium divergens var., Schutt, 1895, pi. 13, figs.

43(22), 43(24). Meunier, 1910, pi. 1 (bis), figs. 1,

2, 7, 8.

Peridinium divergens var. depressa . Aurivillius, 1898,

p. 55. Ostenfeld, 1899, pp. 60, 70, 86, tabs. 1-8.
Peridinium elegans Cleve, 1900a, in part, pi. 7, fig. 16.
Peridinium depressa , Ostenfeld, 1900, tab. 1.
Peridinium divergens var. depressum . Karsten, 1907,

p. 466.
Peridinium kofoidii Faure-Fremiet, 1908, pp. 224-226,

fig. 11, pi. 16, fig. 12. Mangin, 1913, p. 222.
Peridinium marinimi Lindemann, 1925, pp. 98-99, figs.

7-11.
Peridinium marinum var. travectum Lindemann, 1925,

p. 99, fig. 12.

Dimensions . Length of body (i) 187 (114-228) mi-
crons; diameter (d) 137 (108-160) microns. Width of
girdle, about 7 microns. Eighty specimens were meas-
ured.

Shape . Length of body, exclusive of antapical horns,
normally equal to diameter of body at girdle as shown
by the h/d ratio, which is 1.00 (0.77-1.18). The angle a
is 95° (78°-105°). The a/d ratio is 0.39 (0.21-0.65); that
is, length of right antapical horn normally about 0.4
times width of body at girdle. The b/a ratio is 0.14
(0.08-0.27); that is, right antapical horn normally about
0.14 times as thick as long.

Cell body very asymmetrical. Roughly, the mid-
body is a lenticular mass depressed along an anteroven-
tral-posterodorsal axis running at an angle of about 55°
to plane of girdle. Epitheca tapers abruptly on lateral
and dorsal faces, but gradually on ventral side, into an
apical horn which extends along an axis which lies at an

angle of about 65° to the axis of depression of mid-body.
Hypotheca terminates in two antapical horns which are
pointed and more slender than the apical horn. Right
antapical horn may lie parallel to axis of apical horn,
but usually diverges somewhat laterally to the right.
The left one is shorter than the right and diverges from
it laterally and ventrally. The girdle leaves the sulcus
on the left side of the body, curving forward to a point
about halfway to the left side of body, where it begins to
turn gradually backward. This backward curvature is
continued entirely around the body, so that the distal
end of the girdle terminates on the right side of the sul-
cus from 1.5 to 2.5 girdle widths behind the proximal
end. This does not represent the maximum displace-
ment of the girdle, however, which occurs between the
distal end and the front of the curvature to the left of the
sulcus. This displacement is about 3 girdle widths.
The displacement of the girdle can be seen only when
the specimen is viewed ventrally. When the specimen
is allowed to come to rest in a drop of water on its pos-
terodorsal surface, a position commonly represented in
published figures, no displacement of the girdle is evi-
dent (fig. 14A). Girdle not concave. Body reniform in
apical or antapical view, with the indentation at sulcus.
Theg/d ratio, about 0.75. Ventral area narrow, with
more or less parallel sides, 2.0 to 2.5 girdle widths
wide. Sulcus proper deeply embedded, extending to ant-
apex. Anteriorly the ventral area extends very slightly
beyond proximal end of girdle.

Plate pattern . The first symmetrical and first a-
symmetrical patterns occurred in the proportion of a-
bout 4 to 1. The frequency distribution of the two pat-
terns is shown in figure 10.

The apical horn terminates in a more or less trun-
cated apex, about 8 microns in diameter. This region is
much more complex than was at first supposed. It is not
formed simply by the apical ends of the four apical
plates. In fact, the first apical plate ("rhomboid plate"
of Kofoid or "Rautenplatte" of Butschli) does not extend
entirely to the apex. The first apical, or rhomboid,
plate terminates about 9 microns below the apex, where
it borders on a narrow ventral apical platelet (v. a. p.,
fig. 15) which extends to the apex. This platelet is al-
most rectangular in outline, about 9 microns long and
slightly more than 2 microns wide. Its posterior end is
convex, where it fits into an equivalent concavity in the
anterior end of the rhomboid plate. This convexity may
be slight or, in some cases, extreme. Since the rhom-
boid plate does not reach the apex, it is not an apical
plate, strictly speaking. It seems desirable, however,
to retain the term "first apical" for this plate because
the ventral apical platelet is extremely small and per-
haps not equivalent to the other apicals. The possibili-
ty of the homology of this platelet with the major plates
of the other genera, however, should not be overlooked.

The exterior of the apex is formed by the ventral
apical platelet on the ventral side and the anterior ends
of the second, third, and fourth apical plates on the left,
dorsal, and right sides, respectively. The joining of
these plates is strengthened interiorly by a pore plate-
let, sleevelike in form, around which the ends of the ex-
terior plates fit snugly. This apical pore platelet (a. p. p.,
fig. 15) is about 5 microns in diameter and 3 microns
long. Its walls are about 1.5 microns thick, so that the
apical pore, representing the bore of this sleeve, is a-
bout 2 microns in diameter.

The girdle is composed of four plates (lg-4g, fig.

FAMILY PERIDINIACEAE

19

16). The first girdle plate (Ig) is a short plate, about 5
microns long, at the proximal end of the girdle, where
it borders the anterior plates of the ventral area. The
second girdle plate (2g) extends from Ig between plates
Ipr and Ipo, as far as the lateral edges of the latter
plates, so that the suture 2g/3g is continuous with the
sutures lpr/2pr and lpo/2po. The third girdle plate
(3g) is very long and runs completely around the dorsal
side of the body to a corresponding suture on the right
ventral side at the lateral edges of plates 7pr and 7po.
The fourth girdle plate (4g) runs from 3g to the right
side of the sulcus forming the distal end of the girdle.
The skeletal structure of the ventral area is very
complex as compared with the skeletal composition of
the rest of the body. Externally the sulcus is composed
of five plates (figs. 17, 18; pi. 1, figs. A, B). The ante -
rior sulcal p late (a.s.) is at the right anterior end of the
ventral area. Its anterior end runs slightly into epithe-
ca above proximal end of girdle; posteriorly it expands
and forms the anterior edge of flagellar pore. The left
sulcal plate (l.s.) composes most of left side of sulcus.
Its right edge forms the left edge of flagellar pore. The
posterior sulcal plate (p.s.) is a narrow, roughly U-
shaped plate constituting posterior end of sulcus. The
right sulcal plate (r.s.) occupies right side of sulcus and
its left edge forms right edge of flagellar pore.

From both the anterior and posterior edges of the
flagellar pore, there extend into the cell body two inter-
nal processes, the anterior pore process (a. p. p.) and the
posterior pore process (p. p. p.). These processes (figs.
17B, 18A, B) are curved in cross section so that they
form grooves running into the cell body, apparently
forming supporting structures for the two flagella which
emerge from the cell body at the flagellar pore. The
anterior pore process is constructed principally of an
internal extension of the posterior edge of the anterior
sulcal plate. On the right side, it is tied to the right
sulcal plate by the right internal sulcal plate (r.l.s.),
which runs along the entire right edge of the process,
and posteriorly along the left interior edge of the right
sulcal plates, and part way along the posterior pore
process. Along its entire course it is underlaid by a
membrane (m) attached to its adjacent plates. The left
side of the anterior pore process is formed in part by
the anterior groove list (a.g.l.), which also extends part
way along the external portion of the anterior sulcal
plate. The groove in the posterior pore process, as it
comes to the surface, runs posteriorly to the end of the
sulcus. The internal portion of this groove, i.e., the
posterior process, is formed on the right side princi-
pally by an extension of the right sulcal plate. The pos-
terior and left sides are formed by a separate plate,
the posterior accessor y sulcal plate (p. a.s.). Where the
posterior groove runs along the exterior, however, it is
overlaid by a listlike process originating from the sides
of the posterior and right sulcal plates, the p osterior
groove list (p.g.l.). The exterior extension of the pos-
terior groove is open on the left side but covered ven-
trally by this list (figs. 17, 18C; pi. 1, figs. A, B).

The right edge of the flagellar pore is bounded by
the right accessor y sulcal list (r .a.s.), which is attached
along the edge of the right sulcal plate. In its posterior
portion it joins with the posterior groove list.

A cross section of the right sulcal plate (fig. 18D)
shows the curvature of that plate as well as the relative
position of the right accessory sulcal list and the mem-
brane to which the right internal plate attaches.

Thecal wall . Surface of plates sculptured with ir-
regular reticulation which is difficult to demonstrate,
except at intersections, where it is raised into irregu-
lar points.

Pores occur throughout all major plates, irregu-
larly scattered and bearing no relation to reticulations;
absent in girdle plates.

Boundaries between plates vary from simple su-
tures to wide intercalary zones. Rabbet joints present
in all parts of theca (see p. 10). Intercalary zones and
rabbet membranes occur in the girdle at the 2g/3g and
the 3g/4g sutures corresponding to the similar struc-
tures in the plates of the epitheca and hypotheca adja-
cent to the girdle (fig. 16A).

Lists. Cingular lists 8 to 10 microns wide, usually
somewhat broader at the left ventral side. They are
strengthened at the base by short ridges which connect
with similar strengthenings in the girdle and body plates,
and at the outer edge by ridges which extend about half-
way to the center of the list (pi. 1, fig. A).

The apical list (fig. 15; pi. 1, fig. C) encircles the
apex dorsally and laterally, but ventrally it runs down
each side of the ventral apical platelet and extends part
way down the sides of the first apical plate. It forms a
collar around the apex about 2 microns in height, slight-
ly funnel-shaped with serrated edge. Toward the poste-
roventral ends, the list diminishes in width gradually
and terminates on each side of the first apical plate a-
bout 5 microns below the anterior end of that plate. Lat-
erally, from the apex, there is a list on each side which
runs from the apical list posteriorly. The right lateral
list (r.1.1.) extends down the suture between the third
and fourth apical plates, and the left lateral list (1.1.1.)
extends down the suture between the second and third
apicals. These lists are of the same width as the apical
list near the apex, but narrow gradually and end at points
about two-thirds of the way down the third apical plate.
The origin of the apical and lateral lists is not as might
be expected from a study of an intact specimen. Separa-
tion of the apical units, as shown in figure 15B, demon-
strates the attachment of the lists. The apical list is
composed of three parts: the dorsal, right, and left seg-
ments. The dorsal segment of the apical list (d.l.) and
the lateral apical lists are continuous and are attached
to the third apical plate along its anterior and lateral
edges. The left segment of the apical list (l.a.l.) with
its continuation down the ventral side of the horn is at-
tached to the second apical plate along its anterior and
anteroventral edges. The right segment of the apical list
(r.a.l.) with its continuation down the ventral side of the
horn is attached to the fourth apical plate along its an-
terior and anteroventral edges.

In an intact specimen it is difficult to see the apical
list except where one looks through considerable thick-
ness of the list in the arcs which are tangent to the lines
of vision. It thus appears as two spines in whatever
longitudinal view the specimen is observed. This ex-
plains the real nature of the prominences which are fre-
quently shown in figures of this species.

The more carefully drawn figures of this species
have shown that the first apical plate terminates below
the apex, but the space anterior to it has been indicated
as a separation continuous with the apical pore. This
space, as is now shown, is occupied by the ventral api-
cal platelet.

The ventral area is almost entirely bounded by a
system of lists which are attached to the body plates

20

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

surrounding the area. On the left side a wide list, the
left sulcal list (1.1.), runs along the first postcingular
plate (to which it is attached) to the suture between this
plate and the first antapical plate. This list is a contin-
uation of the posterior cingular list. The posterior sul-
cal list (p.l.) extends from the above suture around the
posterior end of the sulcus to the suture between the
second antapical and the fifth postcingular plates. It is
attached to the sulcal edges of the two antapical plates.
Where this list turns from the sides of the sulcus down
to the posterior end, it runs parallel with the line of
vision when the specimen is viewed ventrally. When
viewed on an intact specimen, this list is visible fre-
quently only at the posteroventral corners of the sulcus,
where considerable thickness of the upturned list results
in greater interference of light and gives the impression
of two spines. Specimens have often been figured with
these two "spines" at the bases of the antapical horns.
The posterior right sulcal list (p.r.l.) extends from the
posterior cingular list to the suture between the fifth
postcingular and second antapical plates. It is attached
to the former plate and is continuous with the posterior
cingular list. The right and left sulcal lists, when seen
from the apical or antapical ends, appear as two spines
near the ends of the cingular lists and have frequently
been so drawn or referred to as "teeth" at the base of
the antapical horns. The anterior right sulcal list
(a.r.l.) is a structure of the epitheca. It borders the
right edge of the sulcus which extends into the epitheca,
but is attached to the sulcal edge of the seventh precin-
gular plate and is continuous with the anterior cingular
list.

Variation . There is variation in the habitus of the
species, as can be seen from the specimens presented
in figvire 19. It should be noted that the differences in
the habitus of these specimens are due chiefly to the
variations in the length, thickness, and degree of diver-
gence of the antapical horns, and in the length of the
apical horn. That the pronounced differences in the
shape of the mid-body which are suggested by this figure
are more apparent than real, was demonstrated by pro-
portional measurements of the specimens. These meas-
urements all fell within the limits of the species (p. 16).

For variation in the plate pattern, see p. 14. The
tabulation of the ventral area and girdle is constant.

Comparisons . The species of the "Formenkreis"
P. depressum comprise the greater part of the section
Oceanica of Orthoperidinium . They can be distinguished
from the other species of the section by the inclined gir-
dle. Also, the other species are mostly much smaller,
e.g., P. obtusum Karsten and P. bulla Meunier.

Within the "Formenkreis," P. depressum can be
distinguished from the other species by its body shape.
It Is very similar to P. oceanicum (see p. 15), but can be
distinguished from the latter by its lower _l/d ratio
(less than 1.20) and lower angle a (less than 105°).

Perldinium claudlcanoides n.sp. of this "Formen-
kreis" can be separated from P. depressum by its cune-
ate antapical horns and by its b/a ratio, which is great-
er than 0.23.

Historical . Bailey (1855) described and figured P.
depressum in an easily identifiable manner. Some early
authors, e.g., Pouchet (1883) and Cleve (1900b), consid-
ered this form to be identical with P. diver gens Ehren-
berg (1840). Others, e.g., Bergh (1881) and Meunier
(1910), were somewhat more discriminating and consid-
ered P. depressum to be identical only with the variety

which Ehrenberg (1854) described as P. divergens y
reniform e. It is possible that this variety and P. de-
pressum are identical, but since the figure of Ehrenberg
(p. 240) cannot be identified with any measure of cer-
tainty, and since Bailey's figures are readily recogniza-
ble, it is advisable to retain the now universally accept-
ed name depressum for this species.

Since the importance of the plate pattern in the clas-
sification of the species of this genus was not realized
until the present century, and since neither Ehrenberg
nor Bailey indicated the tabulation for the two species in
question, considerable confusion developed regarding
these forms. There was even a tendency to lump all
large forms of Peridinium under one species, viz., P.
divergens Ehrenberg, which was the first to be described
in the genus.

After Broch (1910) and JOrgensen (1913) had demon-
strated the importance of tabulation in this genus, it be-
came necessary to determine the plate patterns of the
various species which had been described earlier.

In the case of P. depressum this was not difficult,
as the figures of Bailey are easily identifiable. This
form has the Orthoperidinium tabulation, one which was
first indicated for this species by Pouchet (1883, pi. 21,
fig. 26) under the name of P. divergens var. reniforme .

In the case of P. divergens . it is impossible to es-
tablish the tabulation except on an arbitrary basis, since
neither the description nor the figures of Ehrenberg are
identifiable. The first figures of tabulation shown imder
the name of P. divergens are those of Stein (1883), but
unfortunately, as Lebour (1925) states. Stein figured at
least three species under this name. It is not difficult,
however, to select figures 2 to 6 of plate 11, as those
which are most likely to represent Ehrenberg's P. di-
vergens. For the sake of clarifying the confused synon-
ymy of this species, these figures should be accepted,
as Lebour suggested, as establishing the tabulation of P.
divergens . The pattern is that of the section Divergens .
Metaperidinium , of Jorgensen.

The specific distinctness of P. depressum and P.
divergens has been fully realized by most workers in
this field for a considerable period. Meunier, as late
as 1919, figured P. depressum under the name of P. di-
vergens ; however his argument to discard the former
name seems invalid.

Peridinium kofoidii , described by Faure-Fremiet
(1908), is undoubtedly a long-horned form of P. depres -
sum with roughened antapicals. The apical view shows
only three apical plates, but this is probably an error in
drawing, for the dorsal apical plate is difficult to dem-
onstrate in this view.

Distribution . Very common in the boreal Atlantic
Ocean (Paulsen, 1908; Lebour, 1925) and in the Antarc-
tic (Karsten, 1905; Peters, 1928). Matzenauer (1933)
found it frequently in the Indian Ocean and Forti (1922)
in the Mediterranean. Bohm (1936) reported it from the
Pacific between Hong Kong and Shanghai, where its oc-
currence was sporadic. It is apparently a cosmopolitan
species having centers of abundance in the cooler re-
gions of both hemispheres.

In the Carnegie collection this species was found at
35 stations: 22 in the Atlantic, 13 in the Pacific. There
are 72 records of occurrence: 34 rare, 28 occasional,
6 common, and 4 abundant. It was found about equally
at the three levels, with 20 records for the surface, 17
for 50 meters, and 20 for 100 meters. There are 48 net
records and 24 pump records. It was found only in the

FAMILY PERIDINIACEAE

21

northern hemisphere and in the months from May to Sep-
tember.

The Carnegie records exhibit a very curious distri-
bution, being widely scattered in the Atlantic but limited
in the Pacific (fig. 20). In the Atlantic the species oc-
curred from north of the Faeroes Islands as far south as
latitude 13°4 north. Its center of abundance was the
Grand Banks of Newfoundland, where it occurred in enor-
mous numbers clogging the collecting nets, particularly
at 50 and 100 meters depth. In the Pacific it was re-
stricted to a line of stations off Japan and the western
Aleutian Islands, stations 111 to 122.

This species was found in a great range of hydro-
graphic conditions. The surface temperatures at the^
stations where it occurred at any depth varied from6°.9
to 27°6 C. The ranges of hydrographic conditions in situ
were as follows: temperature, -l.°6 to 26.°7 C; salinity,
32.7 to 37.2 o/oo; pH, 7.86 to 8.27; phosphate, 3 to 184
mg P04/m3.

It is obvious from the above data that the factor lim-
iting the distribution of P. depressum has not yet been
identified. Considering the varied conditions under
which the species was found in the Atlantic, it is diffi-
cult to explain its peculiarly restricted distribution in
the Pacific unless its occurrence is normally sporadic,
as Bohm (1936) indicated was the case in the southwest-
ern Pacific.

It is of interest to note that the species exhibited its
greatest variation in the region of the Grand Banks of
Newfoundland (station 13), where conditions were ex-
treme. In this region the surface temperature was 11°27,
whereas at 25 meters 0°.75 was recorded. At 50 meters
the temperature was only -1°.64 and at 100 meters 1°.10.
Curiously enough, the richest collection of P. depressum
made by the Carnegie was at the Grand Banks station at
50 meters. It cannot be concluded that low temperatures
are favorable to this species, because it is quite possi-
ble that the production of this population occurred at a
higher level. It at least indicates that P. depressum can
endure low temperatures. The species seems to be eu-
rythermal to a high degree, for it was again found in the
tropics at temperatures as high as 26°.7. South of sta-
tion 15 (latitude 39° north), however, it was always
found below the surface, a fact which may have been due
to the higher temperatures prevailing at the surface. It
should be noted that the higher concentration of nutri-
ents which occurs below the surface in the warmer wa-
ters may have been responsible for this distributional
peculiarity.

Since the species has a distribution which cannot be
correlated with any known hydrographic condition, it is
at present of no value as an oceanographic indicator.

Peridinium depressum var. parallelum Broch
(Figures 21, 22)

Peridinium parallelum Broch, 1906, pp. 153-157, fig. 2.

Paulsen, 1907, pp. 11, 15; 1908, pp. 39, 54, fig. 68.

Broch, 1908, p. 5. Broch, 1910, p. 52. Mangin, 1913,

p. 221. Paulsen, 1913, p. 279, pi. 47. Pavillard,

1931, pp. 56, 114-116,121, 123, 159, 161, 163, 167, 169,

175, 183, 185, 187, pi. 2, fig. 7A, B.
Peridinium divergens var. Schutt, 1895, pi. 13, fig.

43 (23). Meunier, 1910, pi. 1 (bis), figs. 3, 4.
Perldlniimi antarcticum Schlmper in Karsten, 1905, pp.

37, 38, 40, 43-51, 53-57, 59-61, 64-68, 131-132, pi.

19, figs. 1-4. Broch, 1906, p. 153. Paulsen, 1931

p. 55.

Peridinium depressum subsp. parallelum Broch, 1906,

p. 151.
Peridinium divergens antarcticum . Karsten, 1907, pp.

225, 416.

Dimensions . Length of body (i) 132 (100-160) mi-
crons. Diameter of body (d) 120 (94-138) microns.
Forty-nine specimens were measured.

Shape. This variety is usually more rotund than
the main species, with short and slender antapical
horns, frequently solid part way or entirely to the base,
usually straight and parallel. The h/d ratio is 0.84
(0.73-0.96). The a/d ratio is 0.24 (0.16-0.29). The b/a
ratio is 0.15 (0.10-0.20). Theanglectis 110° (94°-129°).

Plate pattern . Tabulation of major body plates as
in P. depressum with addition of second asymmetrical
pattern found in one specimen. It should be noted that
the first symmetrical and first asymmetrical patterns
occurred in about the same proportion as in P. depres -
sum (fig. 10). Tabulation of girdle and ventral area also
as in main species.

Variation and comparisons . Broch (1906) separat-
ed this variety on the basis of solid antapical horns.
This is not a good character, however, as Peters (1928)
has demonstrated. In our material the solidity of the
horns was a function of the thickness of these struc-
tures. The thinner horns were solid part way or en-
tirely to the base.

The angle a. is low owing to the greater convexity
and shortness of the body. When the specimens were
examined, this convex curvature of the body seemed
characteristic, and in the early part of these investiga-
tions it was .thought that the variety could be distin-
guished on the basis of this character alone. When 108
random specimens of the main species and of var. par-
allelum were measured, however, and the frequency of
their angle a values was plotted, it was found that this
feature is not specific (fig. 23). Rather than two sepa-
rate groups, the frequency distribution suggests a ser-
ies of variable and inter grading units. Since these re-
sults could not be corroborated by the study of addition-
al characters, the attempt to separate the variety on
this basis was abandoned.

Because of the fact that var. parallelum appeared
to have shorter horns than P. depressum . a study was
made of the relative lengths of the antapical horns. The
a/d ratio, representing the length of the right antapical
horn in relation to the width at the girdle, was comput-
ed for 108 random specimens. The values obtained
were grouped into 0.03-unit classes and the frequencies
plotted (fig. 24). This study also showed that there is no
complete separation of two groups. There is an indica-
tion of two groups, however, Intergradlng at the a/d
class of 0.31. This grouping corresponds well to other
differences in habitus, etc. This was the best numeri-
cal measure that could be found to delimit var. paral -
lelum . a fact that clearly shows the uncertain status of
this unit.

Since further knowledge of the differences in the
distribution of these two forms is needed, it is desira-
ble that the occurrence of the forms be kept separate in
plankton lists. As shown by the above frequency studies,
the most effective separation of the variety can be made
by means of the relative length of the antapical horns.
In the present work, the a/d ratio of 0.30 was taken as
the point of separation between P. depressum and var.
parallelum .

22

STUDIES IN THE MORPHOLCX5Y, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

Historical . Broch (1906) described this form as a
subspecies of P. depressum Bailey and later (1910a)
treated it as a distinct species. Paulsen (1908) judged
It to be a valid species, as did Pavillard (1931) and oth-
ers. Peters (1928), however, considered it to be com-
pletely within the variation limits of P. depressum . In
a study of a vast amoimt of antarctic material, he stated
that he found the form always had hollow horns, but in
one sample from the North Sea he found the horns some-
times solid and sometimes hollow. In all dimensional
ratios studied by him he foimd a variation frequency
which suggested the presence of only one systematic u-
nit. He did not consider the a/d ratio, however.

A form resembling var. p arallelum was described
by Schimper (in Karsten, 1905) as P. antarctlcum . Pe-
ters (1928), who studied both northern and antarctic ma-
terial, considered these two forms to be identical. Mat-
zenauer (1933), however, treats antarctlcum as a forma
of P. depressum . Since there is no antarctic material
in the Carnegie collection, it was not possible to subject
this southern form to the analysis applied to var. paral -
lelum . with the result that no direct comparisons could
be made between the two forms.

Distribution . Broch (1906) considered this form a
boreal or boreo-arctic species and stated that in 1905 it
did not come farther south along the Norwegian coast
than latitude 62° north. It must be remembered that he
was considering the solid-spined individuals which prob-
ably represent the extremes of the variety. Paulsen
(1908) stated that it occurred as far south as the Skag-
errack. It occurs in the Antarctic according to Peters
(1928) and in the Indian Ocean according to Matzenauer
(1933). The present records are the first for the Pacif-
ic.

In the Carnegie collection this variety was found at
15 stations: 13 in the Atlantic, 2 in the Pacific. There
are 26 records of occurrence: 8 rare, 11 occasional, 7
common. It was found about equally at the three levels,
with 9 records for the surface, 9 for 50 meters, and 8
for 100 meters. There are 20 net records and 6 pump
records. It was found only in the northern hemisphere,
in the months from July to September.

This variety had a distribution in the Carnegie col-
lection similar to that of the main species in that it was
found at widely scattered stations in the Atlantic but was
restricted in the Pacific (fig. 20). In the Atlantic it was
fotmd in the North Sea (station 6h), at the stations in the
region of Iceland, on the line between Iceland and the
Grand Banks of Newfoimdiand at all stations except one,
and as far south as latitude 11° north (station 23). It did
not occur, however, in a single surface sample south of
latitude 42° north (station 13a). In the Pacific it was
found only at two stations, viz., stations 128 and 130, off
California.

The variety occurred in a great range of hydro-
graphic conditions. The surface temperatures at the
stations where it occurred at any depth varied from8!4
to 27° 2 C. The hydrographic conditions in situ were as
follows: temperature, -l.°6 to 22°4 C; salinity, 32.7 to
36.8 o/oo; pH, 7.87 to 8.26; phosphate, 5 to 176 mg
P04/m3.

It is thus evident that this form cannot be considered
a strictly low-temperature variety, as Broch (1906) sug-
gested. It may have its origin and center of greatest
abundance in the cold regions, but it is highly euryther-
mal. It is hardly possible that var. parallelum repre-

sents an ecological variant, since it often occiirs mixed
with P. depressum .

Peridlnixim depressum var. rectius n.var.
(Figure 25)

Dimensions . Length of body (1.) 124 (113-135) mi-
crons. Diameter of body (d) 84 (76-92) microns. Width
of girdle about 6 microns. Two specimens were meas-
ured.

Shape . Lateral outline in ventral view almost
straight between girdle and bases of horns. This full-
ness of body results in high angle ol . The h/d ratio is
1.10 (1.07-1.19). The a/d ratio is 0.38 (0.37-0.38). The
b/a ratio is 0.17 (0.16-0.18). The angle oc is 120° (111°-
130°). In lateral view the apical horn is continuous with
the body lines. All horns relatively stout. Lengths of
antapical horns similar to those in P. depressum , but
there is little divergence in any direction. Body nar-
rower dorsoventrally than in P. depressum ; sometimes
narrow elliptical in apical view (fig. 25A).

Plate pattern . The epithecal tabulation is of the
first symmetrical pattern. In our specimens the x-ra-
tio was +0.6 and +0.7. Tabulation of other parts as in
main species.

Bodv wall . Intercalary zones wide. Plates thinner
and surface sculpturing much less developed than in
most specimens of P. depressum . Other details same
as in main species.

Comparisons . This variety expresses a tendency
toward a dorsoventral flattening of the body, and a tend-
ency toward a loss of the strong depression of the body
which results in a decrease in the inclination of the gir-
dle. In all these characters it differs from both the main
species and var. parallelum . It is further differentiated
from var. parallelum in its longer and stouter antapical
horns. It is distinguished from var. convexius . de-
scribed below, by its straight, instead of conspicuously
convex, body contours.

In general appearance var. rectius is similar to P.
oceanicum var. parvulum Mangin (1913) fromSaint-
Vaast-la-Houge. It differs from this principally in hav-
ing a low h/d ratio. The h/d ratios computed from
Mangin's figures range from 1 .24 to 1 .45, which places
var. parvulum definitely in the P. oceanicum group.
Fxirthermore, the sides of var. parvulum are more con-
vex than in var. rectius . Mangin did not show a side
view, nor did he state the degree of dorsoventral flat-
tening. (Fig. 10b, lOd of Mangin are ventral views
drawn from the dorsal side.)

Distribution . This variety was found at only two
stations: stations 6 and 32, both in the Atlantic (fig. 20).
The former station was southwest of the British Isles
and the latter in the Caribbean Sea. At the northern sta-
tion the form was collected with the net at 50 and 100
meters, in May; at the southern station with the pump at
the surface, in October. It was rare in each case. The
ranges of hydrographic conditions at these stations were
as follows: temperature, 11°.3 to 28°.0 C; salinity, 35.5
to 36.0 o/oo; pH, 8.08 to 8.23; phosphate, 2 to 41 mg
P04/m3.

The wide range in temperatures indicates that this
form Is eurythermal. Thus, var. rectius is probably a
rare but widely distributed variety of P. depressum Bal-
ley. Type locality: Carnegie station 32.

FAMILY PERIDINIACEAE

23

Perldinlum depressum var. convexius n.var.
(Figure 26)

Dimensions . Length of body (i) 122 (105-135) mi-
crons. Diameter of body (d) 81 (76-88) microns. Width
of girdle about 5 microns. Three specimens were meas-
ured.

Shape . Body very convex in ventral view and does
not flare out in girdle region as in P. depressum . The
h/d ratio is 1.08 (0.96-1.21). The angle a is 128° (114°-
139°). In the girdle region the body is compressed dor-
soventrally so that it is not so convex in lateral view.
The g/d ratio is about 0.70. Antapical horns similar to
those in P. depressum although somewhat more abrupt-
ly pointed. The a/d ratio is 0.40 (0.36-0.46). The b/a
raUo is 0.19 (0.16-0.23).

Plate pattern . Epithecal tabulation is of the first
symmetrical pattern. Other parts of theca as in main
species.

Comparisons. This variety exhibits a peculiar com-
bination of features. It shows a tendency toward a
rounding of the lateral contours of the body as in var.
parallelum . but retains the horn length of P. depressum .
There is also a tendency toward a dorsoventral flatten-
ing, showing a convergence toward the shape of P. de-
pressum var. rectius and P. oceanicum var. tenellum .
Variety convexius can be distinguished from P. depres -
sum by its large angle oc; from var. parallelum by its
longer antapical horns; and from var. rectius by its con-
vex lateral contours.

Distribution . This variety was found at 11 stations:
3 in the Atlantic and 8 in the Pacific. There are 28 rec-
ords of occurrence: 10 rare, 17 occasional, and 1 com-
mon. The records were less frequent for the surface;
there were 5 records for the surface, 11 for 50 meters,
and 12 for 100 meters. There are 18 net records and
10 pump records. The variety was found in both hemi-
spheres, from May to August in the northern, and from
November to January in the southern.

In the Atlantic tliis variety was found at three sta-
tions, all in or along the Gulf Stream, between longi-
tudes 46° and 54° west (fig. 20). In the Pacific it oc-
curred in three regions: (1) off Colombia, station 39;
(2) in the Humboldt Current, off Peru, stations 69 and
70; (3) in a series of stations in the region of Japan, sta-
tions 109-112, 116.

This form probably has its origin in regions of
warm water and it does not seem to endure transfer into
cold conditions. The surface temperatures at the sta-
tions where it occurred at any depth varied from 16 !l
to 27°.4 C. The ranges of hydrographlc conditions insi-
tu were as follows: temperature, 6°.7 to 27°.4 C; salin-
ity, 33.8 to 36.5 o/oo; pH, 7.68 to 8.23; phosphate, 3 to
233 mg P04/m3.

It may be concluded that this is a rare warm-water
form, sometimes being carried into colder regions. It
Is not common enough to be of value as an indicator of
the intrusions of water of tropical origin. Type locality:
Carnegie station 14.

Peridinium depressum forma bisintercalares n.f.
(Figure 27)

Dimensions . Length of body (i) 182 (160-205) mi-
crons. Diameter (d) 132 (125-140) microns. Width of
girdle about 5 microns. Two specimens were measured.

Shape . Body as in P. depressum . The h/d ratio is
0.98 (0.95-1.02). The angle a is 96° (95°-96°). Length
and divergence of antapical horns variable. The a/d
ratio is 0.37 (0.32-0.43). The b/a ratio is 0.12 (0.10-
0.15).

Plate pattern . Epithecal tabulation is of the first
symmetrical pattern except that there are only two in-
stead of three anterior intercalary plates. In the meas-
ured specimens the x- ratio was +0.46 and +2.50.

Comparisons . The distinctive feature of this form
is the presence of two, instead of three, anterior inter-
calary plates, a peculiarity also occurring in P. oceani -
cum (p.24). This pattern is not caused simply by the
fusion of two of the intercalary plates. Although one
specimen of P. oceanicum was found that indicated such
a fusion (p.25), in all other cases some more fundamen-
tal rearrangement had occurred. The suture between
the two plates was located medially where no suture
normally occurs when three plates are present, and the
dorsal pattern was quite symmetrical.

Remarks . Since the subgenus Peridinium is founded
on the presence of three anterior intercalary plates, the
discovery of the two-intercalary forms in P. depressum
and P. oceanicum necessitates the revision of the de-
scription and fundamental classification of the genus.
This plate pattern was too common in the material stud-
ied to be passed over simply as "aberrant." It was
estimated that from 1 to 2 per cent of the specimens of
P. depressum and P. oceanicum in our material showed
this pattern, although in the former species it occurred
only at one station and in the latter at three.

Distribution . This form was found only at station
13 at 50 meters on the Grand Banks of Newfoundland in
August 1928. The hydrographlc conditions were as fol-
lows: temperature, -1°6 C; salinity, 33.4 o/oo; pH, 7.87;
phosphate, 59 mg P04/m3. Type locality: Carnegie
station 13.

Peridinium depressum forma multitabulatum n.f.
(Figure 28)

Dimensions . Length of body Q) 160 microns. Width
of body (d) 135 microns. Width of girdle about 5 microns.
One specimen measured.

Shape . Body shape as in P. depressum . The h/d
ratio is 0.90. The a/d ratio is 0.28. The b/a ratio is
0.24. The angle a is 99°.

Plate pattern. The first apical plate is divided me-
dially by a suture without intercalary striae; the first
precingular is divided transversely; the fourth precin-
gular is divided by a suture in the longitudinal axis; the
first and second intercalary plates are displaced to the
left so that 2a touches 2pr and the suture between 2a
and 3a lies in the longitudinal axis of the body. There
seems to be a tendency toward formation of a cleavage
plane, cutting the body into right and left valves as in
the Dinophysoidae.

Comparisons . This form, of which only one speci-
men was recorded, is peculiar only in its tabulation.

Remarks . The aberrant behavior of the tabulation
in this form strikingly demonstrates the caution which
must be applied in using the plate pattern as the funda-
mental feature of classification.

Distribution . This form occurred in the surface
sample at station 2 in the North Atlantic Drift in May
1928. The hydrographlc conditions were as follows:

24

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

temperature, 20°5 C; salinity, 36.4 o/oo; pH, 8.23;
phosphate, 58 mg P04/ni3. Type locality: Carnegie
station 2.

Peridlnium claudicanoides n.sp.
(Figure 29)

Dimensions . Length of body (i) 166 (154-180) mi-
crons. Diameter (d) 141 (123-150) microns. Width of
girdle about 5 microns. Ten specimens measured.

Shape . Mid-body similar to that of P. depressum .
The angle a. is 94° (79° to 101°). The h/d ratio is 0.75
(0.53-0.94). The body is compressed along an antero-
ventral-posterodorsal axis, running at an angle of about
55° to the plane of the girdle. The epitheca tapers into
a short truncated apical horn which is flattened lateral-
ly at the end so that it is from 1.1 to 1.5 times as wide
in lateral as in ventral view. The horn extends along an
axis which lies at an angle of about 65° to the axis of
depression of the body. The hypotheca terminates in two
stout pointed antapical horns which are more or less
triangular in outline. The a/d ratio is 0.30 (0.27-0.31).
The b/a ratio is 0.28 (0.23-0.35). In lateral view the
axis of the right antapical horn is in line with the axis of
the apical horn, but in ventral view it is seen to diverge
to the right. The left antapical horn is shorter than the
right and diverges from it laterally and ventrally. The
girdle follows approximately the same course as in jP.
depressum .

Plate pattern . The tabulation of the epitheca is of
the second symmetrical, rarely the first asymmetrical,
pattern. Tabulation of other parts of theca as in P. de-
pressum.

Body wall . The external surface of the theca is
faintly marked with an irregular reticulation which is
raised at the intersections so that under low magnifica-
tion the surface appears spinulose. Pores are scattered
irregularly over the surface, and bear no relation to the
reticulations.

The plates are bordered by simple sutures or wide
intercalary zones. Rabbet joints occur as in P. depres -
sum.

Comparisons . This species is close to P. depres -
sum . The mid-body has about the same form as in that
species although somewhat more expanded in the girdle
region, as is expressed by the low angle. It differs fur-
ther from P. depressum in the shorter and stouter api-
cal horn, and in the stout cuneate antapicals. Further-
more, it may usually be distinguished from P. depres -
sum by its plate pattern, which is the second symmetri-
cal. The last feature is not quite reliable, however,
since one specimen was found with the first asymmetri-
cal pattern, a tabulation occurring frequently in P. de -
pressum.

Distribution . P. claudicanoides was found at 9 sta-
tions: 5 in the Atlantic and 4 in the Pacific (fig. 20).
There are 13 records of occurrence: 11 rare, 1 occa-
sional, and 1 common. It was found more often at the
surface, with 7 records for the surface, 3 for 50 meters,
and 3 for 100 meters. There are 11 net records and 2
pump records. The species was found in May in the north
temperate regions of the Atlantic, and in October and
November on both sides of the equator in the tropical
Pacific.

In the Atlantic this form was found at four stations
in the North Atlantic West Wind Drift, stations 1, la, 2,

and 3; and at one station in the Caribbean, station 32.
In the Pacific it occurred only off the coast of Colombia
and Ecuador, stations 35, 35a, 35b, and 40. It is thus
much more restricted in its distribution and occurs In
the Pacific at quite different places from P. depressum .

The surface temperatures at the stations where it
occurred at any depth varied from 15°.5 to 28°.0 C. The
ranges of hydrographic conditions in situ were as fol-
lows: temperature, 13°8 to 27!0 C; salinity, 30.0 to
36.4 o/oo; pH, 7.85 to 8.25; phosphate, 15 to 138 mg
P04/m3.

Peridinium claudicanoides thus appears to be a
rare, warm-water species possibly with a restricted
distribution. It will be noted that it occurred in a wide
range of salinities but never in the barren waters with
low phosphate content. If this correlation is correct, it
is an unusual feature for a tropical form. Type locali-
ty: Carnegie station 2.

Peridinium oceanicum Vanhoffen
(Figure 30)

Peridinium oceanicum Vanhoffen, 1897a, pi. 5, fig. 2.
Vanhoffen, 1897b, pp. 1-2. Jorgensen, 1905, p. 109.
Van Breeman, 1905, p. 44. Broch, 1906, pp. 154-

156. Paulsen, 1907, p. 16, fig. 21. Paulsen, 1908,
pp. 39, 54. Meunier, 1910, p. 27. Broch, 1910, p.
190. Schroder, 1911, pp. 17-19, 21, 40. Mangin,
1913, p. 156. Paulsen, 1913, pp. 279-281, pi. 48.
Jorgensen, 1913, pp. 5-6. Meunier, 1919, pp. 15-19.
pi. 15, figs. 7-23, pi. 16, figs. 21-23. Paulsen, 1931,
p. 66, fig. 37, p. 55. Pavillard, 1931, pp. 56-57,
111, 125, 127, 129, 131, 133.

Peridinium divergens . Stein, 1883, pi, 10, fig.7.

Peridinium depressum var. oceanica , Ostenfeld, 1900,
p. 57, tables 2-7. Gran, 1902, p. 192.

Peridinium divergens var. elegans Cleve, 1900b, p. 260.
Karsten, 1906, pp. 206, 209, 210, 213, 216,217,243,
245-247, 249, 257, 258, 260-261, 265-266,268, 272,
274-277, 279, 285, 287, 289, 293, 295r296, 298, 301,
311-312, 317-318, 328, 330-330,337,352-356, 416,
447, 450, 540. Karsten, 1907, p. 416.

Peridinium depressa var. oceanica , Ostenfeld, 1900, tab.l

Peridinium elegans var., Karsten, 1905, pp. 34, 132, pi.
19, figs. 5, 6.

Peridinium elegans . Karsten, 1905, pp. 179, 208.

Peridinium depressum oceanicum f . typica Broch, 1906,
p. 152.

Peridinium oceanicum f. typica Broch, 1906, pp. 154-

157, fig. 3. Broch, 1910, pp. 190-191.
Peridinium divergens oceanicum Karsten, 1907, p. 224,

227, 228, 230-232, 257, 260-261, 272, 281,290, 416,

447, 450, 472, 540.
Peridinium oceanicum var. typica Paulsen, 1908, p. 55,

fig. 69. Mangin, 1913, p. 222. Lebour, 1925, p. 121.
Peridinium ozeanicum . Schroder, 1911, pp. 16, 25.
Peridinium murrayi var. occidentalis Pavillard, 1931,

pp. 57, 114, 121, 147, 151, 153, 171, 181, 185, 187,

189, fig. 9B, pi. 2.
Peridinium murrayi var. orientalis Matzenauer, 1933,

p. 465, fig. 46b.

Dimensions . Length of body (i) 246 (225-268) mi-
crons. Diameter of body (d) 124 (108-137) microns.
Width of girdle about 5 microns. Thirty-four specimens
measured.

Shape . Body shape similar to P. depressum (seep.
16) but longer and more slender with relatively long
horns. The h/d ratio is 1.42 (1.27-1.68). The a/d ratio
is 0.58 (0.48-0.74). The b/a ratio is 0.12 (0.07-0.15).
The angle ais 119° (109-135°).

FAMILY PERIDINIACEAE

25

Plate pattern . The tabulation is of the first sym-
metrical pattern, rarely of the first asymmetrical. The
latter was observed in one specimen only. The x-ratlo
varied from + 0.70 to +1.30in the symmetrical patterns
and was -1.1 in the specimen with the asymmetrical pat-
tern. Tabulation in other regions as in P. depressum.

Body wall . Details of thecal structure the same as
in P. depressum . In the tropical specimens the body
walls were thinner and the surface sculpturing less de-
veloped than in the northern representatives.

Variation and comparisons . This species is close-
ly related to P. depressum , from which it may be dis-
tinguished by its greater h/d ratio (greater than 1.20)
and by its greater angle <x (greater than 105°). (See p.
15.)

There are a great number of variants of P. oceani -
cum , which have caused considerable trouble among in-
vestigators of this group. (See below.) It is not likely
that this group will be dealt with in an orderly manner
until the description of the body shape is expressed nu-
merically, thus allowing frequency studies for the es-
tablishment of groupings and intergradations.

From the Carnegie material 82 specimens with h/d
ratios greater than 1.20, i.e., specimens belonging to P.
oceanlcum and varieties, were selected at random from
widely scattered oceanic stations in the North Atlantic
and Pacific, and measured. The frequency of their
length classes (fig. 31) indicates two distinct groups:
one with lengths from 140 to 200 microns; the other with
lengths from 220 to 270 microns. Although the two
groups are distinct, they are, nevertheless, close togeth-
er. Since observation of the habitat corroborates this
grouping, it seems justifiable, for the present at least,
to consider the body length as a specific feature sepa-
rating P. oceanicum from its varieties. The group with
greater length is the main species.

In P. oceanicum proper the body form shows a cer-
tain stability, but in the group of smaller forms the var-
iation is extreme (fig. 33). No secondary grouping of
these smaller forms could be accomplished. Therefore
they were lumped into a single group, var. tenellum n.
var.

In addition to this 'variety, which was separated on
the basis of body length and form, three other variants
of P. oceanicum were found which were aberrant in oth-
er features; forma spiniferum n.f. and f. tricornutum
n.f. were segregated on the basis of accessory horns
(pp. 24 and 25), and f. bisintercalares n.f. was estab-
lished on the presence of only two anterior intercalary
plates (p. 24).

Historical . Vanhoffen (1897a, pi. 2, fig. 5) figured
a specimen similar to P. depressum but longer and more
slender. No reference was made to this figure in the
text; but in another paper VanhOffen (1897b) gave a list
of species including the name "P. oceanicum Vanhof-
fen," which has generally been supposed to refer to this
figure. No description of the species was given by Van-
hoffen nor was the plate pattern shown.

This form has been almost universally accepted as
a distinct species related to P. depressum (Jorgensen,
1905; Broch, 1906, 1910; Paulsen, 1907, 1908, 1913;
Mangin, 1913; Pavillard, 1931). Peters (1928) alone has
combined it with P. depressum . Our own observations
also indicate that it should be given specific rating. At
the same time, it is certainly not so easily distinguish-
able as was formerly supposed.

Karsten (1906) confused this species with P. ele-

gans Cleve, a species related to P. grande Kofoid. Kar-
sten's records of P. divergens var. elegans , as he states
later (1907), refer to P. oceanicum VanhOffen. Cleve
(1900b) also confused these two forms.

Kofoid (1907a) described a form, P. murrayi , as
"resembling^, oceanicum " but with "lower epitheca
with more concave sides, longer horn, and longer and
more divergent antapical horns." A figure was given,
and the length given as 250 microns and the width 135
microns. This form seems to have a certain constancy
and is probably specifically distinct. It was figured lat-
er by Pavillard (1931) and Matzenauer (1933). It is, how-
ever, difficult to distinguish Pavillard's P. murrayi var.
occidentalis and Matzenauer's P. murrayi var. orien -
talis from P. oceanicum Vanhoffen.

Distribution . This is a widely spread species. It
has been frequently reported from various parts of the
Atlantic (see Paulsen, 1908; Lebour, 1925; and Pavil-
lard, 1931) and from the Mediterranean (Forti, 1922).
Karsten (1905) reported it from the Antarctic. Karsten
(1907) and Matzenauer (1933) recorded it in the Indian
Ocean. The only records for the Pacific are those of
BOhm (1936) between Hong Kong and Shanghai.

In the Carnegie collection this species was found at
9 stations, all in the Atlantic. There are 17 records of
occurrence: 6 rare, 5 occasional, 5 common, and 1 a-
bundant. It was found about equally at the three levels,
with 6 records for the surface, 5 for 50 meters, and 6
for 100 meters. There are 14 net records and 3 pump
records. All the records are from July and August 1928.

The species was found at all stations between Ice-
land and Labrador, at two stations in the North Atlantic
Drift (stations 15 and 16), and at one station in the North
Equatorial Current, station 21 (fig. 20). It was most a-
bundant in the area between Iceland and Labrador. The
fact that it was not found on the run from Washington to
Plymouth during May might indicate that this particular
occurrence was seasonal. The complete absence of the
main species from the Pacific is very remarkable. All
the Pacific material could definitely be placed in var.
tenellum because of the shorter length.

The surface temperatures at tht stations where P.
oceanicum occurred at any depth varied from 8°.4 to
26°.0 C. The ranges of hydrographic conditions in situ
were as follows: temperature, 4'iO to 26°6; salinity,
34.7 to 36.8 o/oo; pH 7.90 to 8.32; phosphate, 4 to 78 mg
P04/m3.

It is obvious from these observations that this spe-
cies is not restricted to water masses of particular
characteristics even though its center of abundance is
definitely in the colder regions.

Peridinium oceanicum var. tenellum n.var.
(Figures 32, 33)

Dimensions . Length of body (\) 179 (150-205) mi-
crons. Diameter (d) 91 (70-106) microns. Width of gir-
dle about 7 microns. Twenty-seven specimens meas-
ured.

Shape . Similar to main species but less slender.
The h/d ratio is 1.40 (1.25-1.76). The angle a is 126°
(110°-142°). The a/d ratio is 0.58 (0.42-0.67). Theb/a
ratio is 0.12 (0.08-0.16).

Plate pattern . Eplthecal tabulation is of the first
symmetrical pattern. Other areas of theca also as in
main species.

26

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

Variation and comparisons . The variants of P. o-
ceanicum are innumerable. In the Carnegie material
all of them could be separated from the main species by
their shorter length (p. 23). These shorter forms, how-
ever, did not allow further segregation, although they
did not appear to present a homogeneous group. Hence
they were all lumped into the single variety treated
here. There was a great variation in the length, diver-
gence, and thickness of horns, and in the shape of the
mid-body. The numerous varieties of the species pre-
sented by other authors have usually been figured in on-
ly one position, viz., the resting position. The relation-
ships of these forms to each other and to var. tenellum
cannot be determined until statistical studies of body
shape are made. This, of course, cannot be done until
standard methods of presentation and measuring have
been adopted.

Historical. Mangin (1913) described P. oceanicum
var. parvulum as a characteristic form at Saint- Vaast-
la-Hougue. Broch (1910b) described P. oceanicum f.
arupinensis as the typical form of the Mediterranean.

The most commonly cited variant of P. oceanicum ,
however, is P. oblongum Aurivillius (1898). The cur-
rent conception of this form seems to be that it is a
small neritic variety of P. oceanicum . If, however, we
are to accept the figures referred to by Aurivillius, we
must consider this form not only smaller than P. ocean -
icum . but of a somewhat different shape. Aurivillius
referred to figiires 39 and 40 of Bergh (1882) and fig-
ures 44,1 to 44,5 of Schutt (1895). In these specimens
the sides of the body are much straighter than in P. o-
ceanicum. and the apical horn is less definite.

Some recent workers (e.g. Bohm, 1936) are includ-
ing under var. oblongum forms with very rounded bodies
and distinct, long apical horns. As stated above, the re-
lationships of these forms cannot be determined until
frequency studies have been undertaken.

Broch (1910) stated that P. oceanicum and P. ob -
longum have a list only on the right side of the sulcus,
and that f. arupinensis differs in having lists on each
side. Our observations of P. oceanicum and its variants
showed that their morphology agrees with that of all oth-
er members of the section Oceanica in the presence of a
list on each side of the sulcus. This list is, however,
frequently difficult to demonstrate.

Distribution . This variety is widely distributed. In
the Carnegie material it was found at 60 stations: 14 in
the Atlantic and 46 in the Pacific. There are 138 rec-
ords of occurrence: 85 rare, 48 occasional, 3 common,
and 1 abundant. It was found oftener in the upper levels,
with 56 records for the surface, 42 records for 50 me-
ters, and 39 records for 100 meters. It was found in
both hemispheres and in all months of the year.

It occurred in widely scattered areas of the Atlantic
and Pacific oceans (fig. 20). In the Atlantic it was found
in the North Atlantic Drift, south of the British Isles, off
the southeast coast of Iceland, and in the Caribbean Sea.
In the Pacific it occurred at sH ■stations in the general
area between Ecuador and tl j Tuamotus, at Easter Is-
land, at three stations south of latitude 36° south, at 11
stations in the three equatorial currents in the central
Pacific, at 4 stations off Japan, and at 4 stations off the
west coast of the United States.

It was found over a great range of hydrographic
conditions. The surface temperatures at the stations
where it occurred at any depth varied from 10°.3 to

28°6 C. The ranges of hydrographic conditions ]n situ
were as follows: temperature, 6°7 to 28°.6 C; salinity,
32.7 to 36.5 o/oo; pH, 7.71 to 8.39; phosphate, 8 to 220
mg P04/m3.

This form is apparently of world-wide distribution,
occurring in a wide range of hydrographic conditions. It
is noteworthy, however, that it was not found at the Car -
negie stations where the phosphate content of the water
was low, that is, less than 8 mg per cubic meter. This
correlation may be significant in explaining its distri-
bution, since in the warmer areas the phosphate content
is often less than 4 mg/m^. Type locality: Carnegie
station 14.

Peridinium oceanicum forma spiniferum n.f.
(Figure 34)

Dimensions . Length of body (i) 225 (209-241) mi-
crons. Diameter (d) 131 (122-140) microns. Width of
girdle about 5 microns. Three specimens were measured.

Shape . The h/d ratio is 123 (1.19-1.29). The angle
OL is 112° (104°-124°). The a/d ratio is 0.47 (0.43-
0.52); the b/a ratio is 0.11 (0.09-0.14). The distinctive
feature of this form is the presence of an accessory
horn, usually spine -tipped, on the fourth apical plate ei-
ther in the center of the plate or anteriorly. In the spec-
imens observed, this feature did not entail any change in
plate pattern.

Plate pattern . Of the three specimens recorded,
two showed the first symmetrical and one the first a-
symmetrical pattern. In one specimen there was a
lengthening of the suture between 3a and 4pr with con-
sequent shortening of the suture between 3pr and 4pr.

Comparisons . This form has been placed in P. oce -
anicum because most of the specimens had an h/d ratio
greater than 1.20. Furthermore, the horns are attenu-
ated as in that species. The mid-body shows a certain
similarity to P. depressum in its strong depression, in-
dicated by the comparatively low angle a. . This is not
enough, however, to come wholly within the range of P.
depressum .

Distribution. This is one of the diverse forms
which originate on the Grand Banks of Newfoundland,
where organisms are subjected to violent changes in en-
vironmental conditions (p. 19). It was found in the 50-
and 100-meter samples at station 13 on the Grand Banks
of Newfoundland in August 1928. The ranges of hydro-
graphic conditions in which it was found were as follows:
temperature, -1°.64 to -1°10 C; salinity, 33.4 to 33.6
o/oo; pH 7.87; phosphate, 59 to 63 mg P04/m3. Type
locality: Carnegie station 13.

Peridinium oceanicum forma bisintercalares n.f.

(Figure 35)

Dimensions. Length of body (i) 203 (187-224) mi-
crons. Diameter of body (d) 105 (91-125) microns.
Width of girdle approximately 5 microns. Three speci-
mens were measured.

Shape . Similar to P. oceanicum . The h/d ratio is
1.40 (1.38-1.41). The angle a is 128° (121°-135°). The
b/a ratio is 0.13 (0.13-0.15).

Plate pattern . The tabulation of the epitheca in the
specimens examined was of the first symmetrical pat-

FAMILY PERIDINIACEAE

27

tern except that there were two, instead of three, inter-
calaries. In one of the three specimens examined, the
suture between the two intercalaries was so displaced
to the right of the median body line that it appeared to be
the normal suture between 2a and 3a and that the left
plate represented a fusion of la and 2a. In the other
specimens, however, as in the two-intercalary form of
P. depressum . the suture between the two intercalaries
was medially located and thus indicated a more funda-
mental change in the organization of the plate pattern.

Comparisons . This form occupies the same posi-
tion relative to P. oceanicum that P. depressum f. bis-
intercalatum does to P. depressum . It is distinguished
from P. oceanicum only by the presence of two instead
of three anterior intercalary plates.

Occurrence. This form appeared at three stations,
all in the Atlantic: in the North Atlantic West Wind Drift
(station 2) at the surface, on the Grand Banks of New-
foundland (station 13) at 50 meters, and in the Caribbean
Sea (station 31) at 100 meters. Its relative abundance at
the last station was occasional; at the other two stations,
rare. The ranges of hydrographic conditions in which it
was found were as follows: temperature, -l!64 to
22!56 C; salinity, 33.4 to 36.5 o/oo; pH, 7.86 to 8.23;
phosphate, 28 to 58 mg P04/m3.

It is obvious from the above data that the aberrant
pattern exhibited by forma bisintercalares does not ap-
pear under any limited set of hydrographic conditions.
Thus, it is probable that the causes of the development
of this pattern are genetic rather than environmental.
Type locality: Carnegie station 13.

Peridinium oceanicum forma tricornutum n.f.
(Figure 36)

Dimensions. Length of body {V) 203 microns. Di-
ameter (d) 120 microns. Width of girdle about 5 microns
One specimen was measured.

Shape . The general dimensional relationships are
similar to those in P. oceanicum . The h/d ratio is 1.21.
The angle a is 110°. The a/d ratio is 0.48. The b/a
ratio is 0.13. The left side of the mid-body is swollen
into a roughly hemispherical protuburance involving
both the epitheca and the hypotheca. The proximal end
of the girdle has an unusual displacement anteriorly, o-
ver four girdle widths.

Plate pattern . The epithecal tabulation is of the first
symmetrical pattern. The x-ratio is +1.43. The hypo-
thecal side of the hemispherical protuberance is drawn
out into a hollow horn with attenuated tip. This horn is
composed of one plate representing an additional or pos-
terior intercalary plate, inserted between the first, sec-
ond, and third postcingular and the first antapical plates.

Comparisons . Whether this form represents a pre-
mature development of the theca during division, or
whether it is an expression of a definite tendency in the
thecal variation, cannot be determined. It is unique in
that it is the only specimen observed in which any vari-
ation occurs in the hypotheca.

Remarks . Names were assigned with hesitancy to
such aberrant forms as f. tricornutum and f. spiniferum
because of the realization that these forms may repre-
sent pathological conditions. Since there were no defi-
nite indications of the pathological nature of the speci-
mens examined, however, and since some species of the
Peridlnlales, e.g., Ceratium hlrundinella . normally

have multiple horns, it was decided to assign names to
these forms, thus expressing the possibility of their
representing incipient species.

Distribution . The specimen was collected in Au-
gust 1928 in the 50-meter sample at station 13 on the
Grand Banks of Newfoundland, where so many variants
of P. depressum and P. oceanicum were found. The hy-
drographic conditions were as follows: temperature,
-1°.64 C; salinity, 33.4 o/oo; pH, 7.86; phosphate, 60 mg
P04/m3. Type locality: Carnegie station 13.

Artificial Key to the Units of the Section Oceanica
Treated in this Report

A. The h/d ratio less than 1.20; or if greater, the angle
a less than 105° B

A. The h/d ratio more than 1.20 and the angle a great-
er than 105° : H

B. The angle a. 105° or less C

B. The angle a greater than 105° F

C. Epitheca with 2 intercalary plates

P. depressum f.bisintercalatum n.f.

C. Epitheca with 3 intercalary plates D

D. Epitheca composed of 17 major plates

P. depressum f. multitabulatum n.f.

D. Epitheca composed of 14 major plates E

E. Antapical horns cuneate; b/a ratio greater than 0.23;
epithecal pattern usually second symmetrical . . .
P. claudicanoides n.sp.

E. Without this combination of characters

P. depressum Bailey

F. The a/d ratio less than 0.30

P. depressum var. parallelum Broch

F. The a/d ratio more than 0.30 G

G. Lateral contours of body convex

P. depressum var. convexius n.var.

G. Lateral contours of body straight or slightly convex .
P. depressum var. rectius n.var.

H. Epitheca with 2 intercalary plates

P. oceanicum f. bisintercalares n.f.

H. Epitheca with 3 intercalary plates I

I. Fourth apical plate bearing a prominent spine . . .

P. oceanicum f. spiniferum n.f.

I. Fourth apical plate not bearing a prominent spine .

J
J. Hypotheca with an intercalary plate bearing a horn

P. oceanicum f. tricornutum n.f.

J. Hypotheca without such a plate K

K. Total length (j.) less than 210 microns

P. oceanicum var. tenellum n.var.

K. Total length (1) more than 210 microns

P. oceanicum VanhOffen

Peridinium crassipes Kofoid
(Figure 37)

Peridinium crassipes Kofoid, 1907a, pp. 309-310, pi. 31,
figs. 46, 47. Paulsen, 1907, p. 17, fig. 24. Paulsen,
1908, p. 58, fig. 73. Broch, 1908, p. 5. Broch, 1910b,
p. 52, fig. 27. Okamura, 1912, p. 18, pi. 4, figs. 63a-
c. Lindemann, 1924, p. 230, pi. 4, figs. 80-86. Pe-
ters, 1928, p. 42, figs, lla-h. Matzenauer, 1933, p.
467, fig. 50. Bohm, 1936, p. 41, fig. 16c.

Dimensions. Length of body (1) 105 (88-120) mi-
crons. Width of body (d) HI (90-130) microns. Width
(g) 80 (65-94) microns. Width of girdle about 6 microns.

28

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

Twenty-two specimens were measured.

Shape . Body short and wide, resembling somewhat
P. depressum var. parallelum Broch. TheJ/d ratio is
0.95 (0.80-1.04). The h/d ratio is 0.76 (0.60-0.86). In
ventral view both the epitheca and the hypotheca rather
abruptly constricted distally. The angle a is 89° (74°-
102°). Apical horn 1/4 to 1/3 total length of epitheca;
base broad. Apex about 1 girdle width in diameter. Ant-
apical horns terminated by solid spines. Right horn a-
bout 2 girdle widths longer than the left. There is no
dorsoventral compression of the body in the girdle re-
gion, so that in apical view, the body is almost circular
except for the deep indentation at the sulcus, which is
about 3 girdle widths deep. The g/d ratio is 0.73 (0.64-
0.80). There is sometimes a slight development of ven-
tral limbs in the girdle region (as seen in apical view),
but this is not very marked.

The girdle is equatorial, sinistral, displaced about
2 girdle widths. The ends of the girdles themselves
are scarcely (about 0.5 girdle width) displaced, however,
owing to the posterior curvature of the distal end. There
is no girdle overhang; the girdle ends are separated by
the anterior end of the ventral area. Girdle slightly con-
cave. In side view the girdle is seen to be inclined at an
angle of 75° to the longitudinal axis (the axis running
from the apex to the antapex of the body).

The ventral area extends from the anterior edge of
the girdle posteriorly to the antapex, which is located
almost centrally (when specimen is seen in antapical
view). Area subtruncate anteriorly; rounded posterior-
ly; left side almost straight; right side angular so that
the greatest width, equaling about 4 girdle widths, oc-
curs about one-third of distance from girdle to right
antapical horn. Right side of ventral area on a level
with, and taking a prominent place in, the ventral aspect
of main body; but left side of area scarcely evident on
the main body. Flagellar pore roughly elliptical in out-
line and about 2.5 girdle widths long, lying in the middle
of sulcus proper, which occupies left half of ventral a-
rea. Sulcus rotated on its longitudinal axis in such a way
that pore faces more to the left than ventrally. Sulcus
and pore covered by left sulcal list.

Plate pattern . Epithecal plate pattern typical of di-
vergens group, with first apical touching precingulars 1,
2, and 7, and apicals 2 and 4; and with second anterior
intercalary touching only fourth precingular (fig. 37A).
Preclngular plates fairly evenly spaced around girdle.
Precingular 2 has a somewhat smaller girdle margin
than its fellow, precingular 6, on the right side, but this
discrepancy is not nearly so pronounced as in the case
of P>. truncatum (p. 28).

Hypothecal pattern typical of genus (fig. 37C). At
apex there are 2 platelets in addition to apical plates, as
in P. depressum . Ventral apical platelet about 1 girdle
width long. Apical pore platelet a ring structure simi-
lar to that in P. depressum .

Girdle consists of four unequal plates (fig. 37D).
First girdle plate (gl) is a short, squarish plate adjacent
to the ventral area. The second and fourth (g2, g4) about
equal In length and occupying the ventral portions on the
two sides of girdle. Lateral and dorsal sides of girdle
composed of the long third girdle plate (g3).

Ventral area composed of six plates (fig. 37E, F).
Only four of these are visible in undissected specimens,
the other two hidden as in the case of P. depressum. All
plates homologous with those in P. depressum . a species
with a ventral area in many respects similar to that of

P. crassipes . (See comparisons.) Anterior sulcal p late
(as) occupies most of the anterior part of the area and
forms anterior margin of flagellar pore. Left sulcal
plate (Is) comprises most of the left side of sulcus and
forms left edge of flagellar pore. Right sulcal p late (rs)
occupies most of right side of ventral area, is raised
practically to the level of the main body plates, as in P.
truncatum (p. 28), and forms right margin of flagellar
pore and sulcus proper. Posterior sulcal plate (ps)
forms posterior part of the area and is U-shaped in out-
line. Its right side is expanded into a squarish process
which lies posterior to right sulcal plate. Its middle
portion is very narrow. Its left side is elongated into a
slender process which borders posterior left edge of the
sulcus and is raised to the level of the body plates, fit-
ting in between the first postcingular and first apical
plates. This portion bears the posterior part of the left
accessory sulcal list on its inner margin. At the poste-
rior edge of flagellar pore between the right and the left
sulcal plates is a small, squarish, trough- shaped plate,
the posterior accessor y sulcal plate (pas). Along the
right side of pore, underneath the left edge of the right
sulcal plate, is a thin plate, the right internal sulcal
plate (ris), which has a posterior arm turned into the
body of the specimen. A similar projection into the pro-
toplast at the anterior edge of the pore is not a separate
plate but a process on the under side of the anterior sul-
cal plate.

Body wall . Body plates and some sulcal plates cov-
ered with a light reticulation which is usually irregular-
ly raised at the angles of the meshes. Size of meshes,
except over rabbeting membranes, from 0.3 to O.Sgirdle
width. Over these membranes, in individuals without in-
tercalary zones, the meshes are noticeably larger, 0.6
girdle width or more; but reticulations are much less
well developed, the thecal wall appearing thinner; and no
pores occur. In the more finely reticulated areas, there
are fairly regularly spaced pores, usually one per mesh.
In these areas the thecal wall is thicker and the meshes
of the reticulations sometimes give the appearance of
pits, although their edges are always angular. The gir-
dle plates do not bear these reticulations, but have ir-
regular transverse ridges which usually extend only half -
way from the edge of the girdle, and may be connected,
forming a sort of reticulation. There are no pores in the
girdle although the median line of the girdle has a spon-
gy nature. Intercalary zones are common.

Lists. Girdle lists about 1 girdle width wide and
strengthened by small ribs which extend centripetally
from outer margin halfway to body. These ribs are
placed from 0.2 to 0.3 girdle width apart. In the apical
region there is a system of lists similar to that in P. de-
pressum except that the most distal parts are less well
developed. The lists running down the body from the a-
pex are larger than in P. depressum , sometimes being
as much as 1.5 girdle widths wide. The lateral ones (at-
tached to ap3) usually visible in ventral and dorsal viewa
The right and left segments of the apical list (ral, lal,
fig. 37G), which run down the ventral side of the body
and are attached to the fourth and second apicals, re-
spectively, are clearly seen when specimen is viewed in
lateral aspect.

Lists in the sulcal region well developed. Left sul -
cal list continuous with posterior girdle list and at-
tached to po; continuous posteriorly with the left acces -
sor y sulcal list (la), which it? attached to the right edge
of the left limb of the posterior sulcal plate (ps). The

FAMILY PERIDINIACEAE

29

left sulcal and the left accessory sulcal lists form the
functional left sulcal list. They are very broad, about
1.5 girdle widths wide, except at their point of junction,
where they are constricted to 0.7 girdle width. Posteri-
orly, the left accessory sulcal list extends as a free sail
about 1.5 girdle widths long. These two lists extend
more or less laterally over the sulcus, covering all its
left half and tl\e flagellar pore. Right sulcal list very
small. Posterior sulcal list well developed medially,
having a width of about 0.7 girdle width, but rapidly di-
minishes anteriorly as it runs up the sides of the sulcus
The right accessor y sulcal list (ras) is thick and nar-
row, overhangs the flagellar pore on its right side, and
continues posteriorly to the posterior sulcal plate, form-
ing a trough with the posterior accessory sulcal plate.
There is no posterior accessory sulcal list.

" Spines ." Solid antapical spines end antapical
horns. They are about 2 girdle widths long; the right
is slightly longer than the left. Cursory examination of
intact specimens in ventral view shows a spine posteri-
orly at each side of sulcus. Spines are simply optical
effects produced by the greater absorption of light at
points where line of vision falls on tangents of the cur-
vature of the posterior sulcal lists. Lists are difficult
to see because of transparency, except at these spines.

Comparisons . Peridinium crassipes is distin-
guished from other species of Metaper idinlum by its
short, broad body and by its short horns.

It is of particular interest to compare the ventral
area of P. crassipes with that of P. depressum and that
of P. truncatum . since crassipes has a structure which
in some respects is transitional between the latter two
species. The margins of the ventral area are similar to
those in P. truncatum . The body sutures have the same
relation to those of the ventral area as in that species.
The tabulation of the ventral area is transitional be-
tween P. depressum and P. truncatum . The largest
plate of this area, the right sulcal, is raised so that it
forms part of the body proper, as in P. truncatum . On
the other hand, the region immediately surrounding the
flagellar pore agrees well with P. depressum . There
are internal structures at the anterior and posterior
ends of the pore. A semilunar structure occurs at the
right edge of the pore on the internal surface of the right
sulcal plate. This structure is composed partly of an
internal plate, the right internal sulcal plate, as in P.
depressum. The very small posterior accessory sulcal
plate is probably homologous to the similar plate in P.
depressum and the larger plate of the same name in P.
truncatum .

The sulcal list system is also transitional between
P. depressum and P. truncatum . The right accessory
sulcal list ends at the posterior end of the right sulcal
plate, as in P. depressum ; it does not join with any pos-
terior accessory list as is the case in P. truncatum .
The course of the left accessory sulcal list is as In P.
truncatum . Otherwise the lists of the posterior region
of the sulcus are quite different from those in that spe-
cies and are similar to those in P. depressum . There
is no posterior accessory list connecting the right and
left accessory lists, and the left accessory list extends
posteriorly as a free lobe.

Historical . Kofoid (1907a) described this species
from the neritic plankton off San Diego, California.

Paulsen (1908) considered figs. 43, 1-2 of Schutt
(1895) to represent this species, but in our opinion this
is uncertain. The side view (fig. 43, 2) might well be P.

crassipes . but the dorsal view (fig. 43,1) does not show
sufficient expansion in the girdle region.

The antarctic form reported by Peters (1928) is
distinctly different from the northern form, but Peters
considers the two forms to fall within the limits of a
single species. The antarctic form has a peculiar an-
gularity of the body and thickness of antapical horns not
found in the northern form.

Jorgensen (1913) separated P. curtipes from P.
crassipes , on the basis of its yellow, instead of pink,
color; its greater expansion in the girdle region, and
the shape of the girdle on the left ventral side. Lebour
(1925) accepted this species of JOrgensen but Peters
(1928) rejected it. Peters pointed out that species of
Peridinium cannot be distinguished by their color, as
this is variable. He also was of the opinion that the
shapes of the body and girdle are indistinguishable in P.
curtipes and P. crassipes . Matzenauer (1933) accepted
P. curtipes and figured a specimen with even greater
expansion of the girdle region than that of Jorgensen's
species, and with short, conical, divergent antapical
horns.

Since both these species have been very inadequate-
ly figured, and especially since very little is known re-
garding any morphological feature of P. curtipes , it is
not possible at this time to pass a proper judgment on
the authenticity of P. curtipes .

The ventral area of P. crassipes had not been ana-
lyzed until the present investigations. Kofoid's (1907a)
figures show that certain parts of the area are promi-
nent and on a level with the main body plates, but even
the main features of the area are omitted and the flagel-
lar pore is erroneously indicated at the anterior end of
the ventral area.

Distribution . Peridinium crassipes is probably
widespread. If we consider Jorgensen s P. curtipes as
Peters (1928) suggested, we have records of occurrence
from all parts of the Atlantic (Lebour, 1925). Under the
name P. crassipes , it was reported from the Antarctic
by Peters (1928), and from the Indian Ocean by Matzen-
auer (1933), and from the Mediterranean by Forti (1922)
and Issel (1928). In the Pacific it was reported from San
Diego, California, by Kofoid (1907a), and from the east-
ern Pacific, between Hong Kong and Shanghai, by Bohm
(1936).

The Carnegie collection furnishes many new locali-
ties for this species in the Pacific, viz., 50 widely scat-
tered stations in the tropical and subtropical regions
(fig. 38). There are 107 records of occurrence; 63 rare
and 44 occasional. It was found about equally at the
three levels, with 30 records for the surface, 39 for 50
meters, and 38 for 100 meters. There are 14 pump rec-
ords and 93 net records. The species was found in both
hemispheres in all months of the year except June, July,
and August. The records of "occasional" are scattered
irregularly over its range.

The Carnegie records of P. crassipes are limited
entirely to the Pacific. In the eastern Pacific it was not
found north of Guam, whereas in the western Pacific it
occurred as far north as latitude 33° north and as far
south as latitude 40° south.

The surface temperatures at the stations where the
species occurred at any depth varied from 15°.0to28°.6C.
The ranges of hydrographic conditions in situ were as
follows: temperature, 10°.8 to 28°.3 C; salinity, 31.6 to
36.4 o/oo; pH, 7.76 to 8.47; phosphate, 3 to 159 mg
P04/m3.

30

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

The distribution of P. crassipes at the Carnegie
stations is unexplainable unless we assume that the oc-
currence is sporadic. The species is eurythermal and
has been found by other investigators over wide areas of
the Atlantic, from the tropics to the North Sea, yet it was
absent from all Carnegie stations in the Atlantic. In the
Pacific, in the Carnegie collection, it occurred mostly
in the warmer regions but was not found on the line of
stations between Guam and San Francisco, which passes
through both cold- and warm- water regions. It did oc-
cur, however, in the southeastern Pacific in water of
low temperature.

Peridinium truncatum n.sp.
(Figures 39-41)

Dimensions . Total length (1^) including the apical
and right antapical horns 230 (196-265) microns. Length
(h) from tip of apical to posterior end of sulcal 161 (138-
210) microns. Diameter (d) 159 (130-200) microns. Di-
ameter (g) 80 (65-105) microns. Width of girdle 5-6 mi-
crons. Twelve specimens were measured.

Shape . Body shape characterized by pronounced
features. Mid-body compressed anteroposteriorly in
girdle region, especially at the sides, to such a degree
that the lateral sides are scarcely thicker than the gir-
dle is wide (fig. 39E). In contrast with this extreme
compression of the mid-body, all the horns are so long
that the epitheca as well as the hypotheca is about 1.5
times longer than the dorsoventral diameter. The 1/d
ratio is 1.45 (1.27-1.57). The h/d ratio is 1.01 (0.91-
1.17). The angle a is 47° (34°-65°). The rapid taper of
the mid-body into the horns is roughly the same on all
sides; thus the horns are almost symmetrical and the
marginal curvatures of the mid-body are similar in ven-
tral and lateral views. All horns are tubular distally
and elongated. Distal one-third to one-half of antapical
horns are of uniform diameter. End of apical horn a-
bout 1.5 girdle widths wide; ends of antapicals about 1
girdle width. Antapical horns truncate to slightly round-
ed, but never pointed.

In apical view the body is basically reniform but
with ventrolateral limbs greatly elongated. Since the
prolongation of these limbs is a fundamental character-
istic of the species, it is necessary to express it numer-
ically in order that a proper delimitation of the species
may be obtained. For this reason, the width of the limb
(r) was measured as described on page 13 (fig. 8). This
width is best expressed as a fraction of g. The r/g ratio
in this species is 0.47 (0.43-0.51). Although this ratio
is sufficient to characterize the species, it is notewor-
thy that the length of each limb, measured from the apex
of the body, is at least 1.25 times the dorsoventral di-
ameter of the body. Another measurable feature which
is significant in this connection is the ventral projection
of these limbs; this projection, beyond the median ven-
tral point, is usually 0.5 times the dorsoventral diame-
ter of the body. The g/d ratio is also characteristic,
being 0.48 (0.41-0.54).

There is practically no real displacement of the
girdle, although there is frequently an apparent one if the
specimen is not seen in an exact ventral view. This ap-
parent displacement may be dextral or sinistral depend-
ing on the direction of displacement of the specimen.
Girdle ends separated by the wide anterior portion of
the ventral area. In lateral view the girdle is seen to be

inclined about 15° to the longitudinal axis. It is only
slightly concave.

Ventral area occupies a large part of ventral sur-
face of body. About half the area of the right ventral
portion of the hypotheca and part of the posterior left
portion are composed of elements of the ventral area.
These parts of the ventral area occupy an integral part
of the body and are set into the general body contours
without any break. Sulcus proper composed of the cen-
tral elements of the ventral area (see below). Flagellar
pore oval, about 3 girdle widths long, and situated some-
what anterior to center of ventral area. The sulcus is
so rotated on its longitudinal axis that the pore faces to
the left rather than ventrally. Pore covered by sulcal
lists so that it does not face the exterior directly.

Plate pattern . Pattern of major body plates typical
of divergens group. At the apex of body, there are 2
platelets in addition to the apical plates. Ventral apical
platelet long and narrow, more than 7 girdle widths long,
lying just anterior to the first apical and between the
second and fourth (fig. 39C, E). Apical pore platelet is
a ring platelet, set inside the ends of apicals 2, 3, and
4, and the ventral apical platelet.

Epithecal pattern not symmetrical In respect to pre-
cingular plates. Precingular 2 is much narrower, both
relatively and actually, than corresponding plate on right
side, precingular 6. The girdle border of pr2 usually
less than one-fourth that of pr6 (fig. 39A). To compen-
sate for this, pr3 has a much longer girdle margin than
its fellow pr5 on the right side. Precingular 2 narrows
very markedly toward girdle, so that its width at girdle
may be as little as one-half its greatest width.

Girdle composed of four unequal plates (fig. 39G).
First girdle plate somewhat narrower than long (fig.
39D). Second and fourth extend on either side of sulcus
almost to the most ventrolateral points of girdle on each
side. The rest of the lateral and dorsal parts of girdle
consist of the extremely long third plate.

Pattern of hypothecal plates typical of divergens
group. Sulcal plates take a prominent place in the ven-
tral aspect of body, a characteristic feature in this spe-
cies. Right sulcal plate occupies a large part of ventral
surface of hypotheca. The left limb of the posterior sul-
cal plate fits into the major body plates between the first
postcingular and first antapical (fig. 39E) in such a way
that it might be mistaken for a major body plate in un-
dissected specimens.

Ventral area composed of five plates, all external
(fig. 39D). Anterior sulcal plate occupies most of the
area between the ends of the girdle and forms anterior
margin of flagellar pore. It bears a process at its pos-
terior end which projects into the cell body. Left sulcal
plate occupies the left central and the posterior central
regions of the ventral area and, in its anterior half,
forms the left margin of the flagellar pore. Posterior
sulcal plate more or less U-shaped, forms posterior
part of ventral area, is far removed from flagellar pore,
and is very complex. Its left limb forms a large, four-
sided area in the hypotheca, extends from antapex half-
way to girdle, and fits into the hypothecal pattern poste-
rior to first postcingular. Its right limb lies posterior
to sulcal plate and is also raised to a position where it
must be considered part of the hypothecal pattern (fig.
39E). The right sulcal plate , which is the largest in the
ventral area, extends from posterior sulcal plate to epi-
theca, where it has a narrow extension lying against the
distal end of girdle and against seventh precingular. Ii.

FAMILY PERTDINIACEAE

31

its middle part it forms tlie rigiit margin of flagellar
pore. It is definitely raised to a position equivalent to
that of a hypothecal plate. In its anterior half it has a
dome- shaped prominence which rises over the flagellar
pore (fig. 41). At the middle of the left side of this
plate, at the posterior end of the flagellar pore, there is
a process which projects into the cell body (fig. 39F).
Between the posterior half of the left sulcal plate and
the posterior half of the right sulcal plate there lies a
narrow plate about 4 girdle widths long, the posterior
accessor y sulcal plate , the homologue of the very mi-
nute plate at the posterior end of the flagellar pore in P.
depressum and P. crassipes . Anteriorly it touches the
flagellar pore, and posteriorly, where it borders the
posterior sulcal plate, it is about 3 times wider than at
the anterior end. There is no detachable semicircular
plate such as occurs in P. depressum and P. crassipes .

Body wall . Entire surface of the major body plates
and of all the sulcal plates, except the left and posterior
accessory sulcal plates, covered with a very prominent
coarse and regular reticulation. Plates lacking this are
entirely smooth. Reticulation so deep on apical and ant-
apical horns, especially in their distal parts, that it
gives the impression of "spinlness" along the edge of
the horns. Girdle plates with irregularly spaced trans-
verse ridges which may extend completely across the
girdle or only part way from the margin on either side.
The major body plates, the girdle plates, and the sulcal
plates are pierced by minute, irregularly scattered
pores. Arrangement of these pores bears no relation to
reticulations. Usually one or two pores per mesh; those
on the girdle plates not arranged in rows.

Intercalary zones not found in our material, except
in two specimens.

Lists . Girdle lists comparatively narrow, usually
less than 1 girdle width wide; strengthened by fairly
regularly spaced ribs, usually extending completely from
body to outer edge, but in some cases extending only
part way from body or from outer edge.

The apical list system similar to that in P. depres -
sum . except for a lesser development generally and for
the absence of the lateral lists. The lists in this region
are only 0.25-0.50 girdle width wide. Apical list encir-
cles apex and is composed of three segments: the dor -
sal , right , and left. Dorsal segment attached to tip of
third apical and not joined by any lateral lists as in P.
depressum . P. crassipes . and P. pallidum . Right and
left segments are attached to apical and ventral edges of
second and fourth apical plates and continue down the
ventral side of the body only as far as the posterior end
of the ventral apical platelet (at the anterior end of the
first apical plate). Ventral apical platelet is set deeply
between these two lists (fig. 39C, E, H).

Development of sulcal lists in this species is of par-
ticular interest. Left sulcal list is well developed in re-
spect to its width, which is from 1.0 to 1.5 girdle widths.
The list extends laterally over the left anterior part of
the sulcus, overlapping the anterior end of the right ac-
cessory list and flagellar pore. It is continuous with the
posterior girdle list and is attached to the first postcin-
gular plate. Therefore, it can extend only halfway down
the side of the ventral area. At this point it joins the
left accessor y sulcal list , which is just as wide as the
left list but projects ventrally from the body. It is at-
tached to the left limb of the posterior sulcal plate, and
is continued around the posterior region of the sulcus as
the posterior accessory sulcal list . This list, which is

attached to the posterior sulcal plate, is narrower than
the last mentioned list and joins the p osterior sulcal
list at the right posterior corner of the ventral area.
Posterior sulcal list is a poorly developed list along the
posterior margin of the ventral area. It is composed of
two segments; the left segment, which is attachedtothe
first antapical plate, and the right segment, which is at-
tached to the second antapical plate. Right sulcal list is
absent. In other species it runs along the right edge of
the right sulcal plate (attached, however, to body plates)
and defines the right margin of the sulcus proper. In
this species its absence coincides with the raising of the
right sulcal plate to the position of a major body plate.
The functional list to the right of the sulcus proper in
this species is the right accessor y sulcal list. It is at-
tached to the left edge of the right sulcal plate. It ex-
tends laterally over the flagellar pore and the posterior
part of the sulcus. Posteriorly it connects with the pos-
terior accessory sulcal list but has a free lobe extend-
ing posteriorly (fig. 39D, E). The posterior accessory
list extends along the anterior edge of the middle and
right parts of the posterior sulcal plate.

Comparisons . This species is rather closely relat-
ed to P. elegans Cleve (a species not treated in this re-
port) but may be distinguished from the latter by its
greater expansion in the girdle region, much greater de-
velopment of the ventrolateral body limbs, trimcated
antapical horns, and shape of the second precingular
plate. The r/g ratio is 0.47, as compared with 0.84 for
P. elegans . The second precingular plate in P. trunca -
tum narrows toward the girdle, whereas in P. elegans it
widens. The girdle margin of this plate in P. truncatum
is less than one-fourth that of po6; in P. elegans that
margin is more than half that of po6. Furthermore, P.
truncatum is a larger species, with an h/d ratio on the
average greater than that of P. elegans .

A comparison between the ventral areas of P. trun -
catum and P. depressum is of interest. Although the
areas are constructed on the same fundamental plan,
with all plates homologous, they show many marked dif-
ferences in pattern, contours, and lists.

The sulcal plates in P. truncatum show a definite
tendency to become major body plates. Thus a smaller
number of plates form the sulcus proper in P. truncatum
than in P. depressum . In P. depressum the left limb of
the posterior sulcal plate is quite inconspicuous, where-
as in P. truncatum it is prominent and fits into the main
body complex posterior to pol. The right limb of the
posterior sulcal plate likewise is prominent in undis-
sected specimens of P. truncatum . whereas in P. de-
pressum it is quite obscure. The right sulcal plate in P.
truncatum is a prominent feature of the ventral aspect
of the hypotheca, whereas in P. depressum it is a com-
paratively obscure plate of the sulcus. In P. depressum
it has a trough running the length of it, whereas in P.
truncatum this plate is convex and actually humped in
the anterior half. In the sulcus of P. depressum there
is a right internal sulcal plate; in P. truncatum this is
absent. The posterior accessory sulcal plate is minute
in P. depressum . but in P. truncatum it is 4 girdle
widths long.

The positions of the sulcal plates in relation to the
plates of the body differ considerably in the two species.
In P. truncatum the suture between po5 and ant2 reaches
the ventral area in the middle of the right sulcal plate,
whereas in P. depressum this suture runs much more
posteriorly and reaches the ventral area in the middle

32

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

of the right arm of the posterior sulcal plate. The su-
ture between pol and antl, although not exactly compar-
able in the two species, shows a fundamental difference
in its course. In P. depressum it reaches the sulcus
far posteriorly, whereas in P. truncatum it reaches the
sulcus about midway of its length, about at the midpoint
of the left sulcal plate. In P. trtincatum the left limb of
the posterior plate extends anteriorly to meet this su-
ture. All together these differences in sulcal plate pat-
tern are greater than the differences between the typi-
cal epithecal patterns of the ortho and meta groups of
the genus.

The sulcal list systems of P. truncatum and P. de -
pressum are as fundamentally different as are the plate
patterns. In P. depressum the functional border list of
the right side of the ventral area is the right sulcal list
(rl, fig. 17), which is attached to the body plates along
the right edge of the ventral area. In P. truncatum this
list is practically imdeveloped and the fimctional right
border list is the right accessory sulcal list (ras, fig.
39), which in P. depressum is located deep within the
sulcus proper. There is a similar difference between
these two species as regards the left side of the sulcus.
The posterior girdle list and the anterior part of the
left sulca! list are continuous in both species, but the
posterior part of the left sulcal list has quite different
positions in the two species. In P. depressum this part
is located at the left margin of the deep sulcus and is
continuous with the anterior part of the left sulcal list
and with the posterior sulcal list, which, in turn, runs
around to meet the right sulcal list. Thus, the ventral
area is bordered by three lists: the primary left, the
posterior, and the right sulcal lists. In P. truncatum ,
concomitant with the expansion of the ventral area,
these bordering lists have been subordinated or lost
compleiely and there has been a development of acces-
sory lists bordering the sulcus proper, which occupies
only a limited part of the ventral area. The anterior
part of the left sulcal list connects with the left acces-
sory sulcal list (la), which is joined to the posterior ac-
cessory sulcal list (pal); this, in turn, is joined to the
right accessory sulcal list (ras).

The ventral area of P. truncatum is not so different
from that of P. crassipes as it is from that of P . depr es -
sum. For a comparison of these features in P. trunca -
tum and P. crassipes . see "Comparisons" under P.
crassipes .

The very marked differences in the structure of the
ventral areas which were found in these species, as ex-
emplified by the comparison of P. depressum and P.
truncatum . are of the greatest importance to the taxon-
omy of the genus. It is probable that the future classi -
fication of the species of Peridinium will be based on
the morpholog y of the ventral area.

Historical . The figures of (%amura (1912, pi. 4, fig.
58a-c) given under P. fatulipes probably refer to this
species. Otherwise, it apparently has not been reported
before.

Distribution . Peridinium truncatum was found at
24 stations, all in the Pacific. There are 46 records of
occurrence: 27 rare, 16 occasional, and 3 common. It
was foimd less at 100 meters than at the other levels,
with 16 records for the surface, 20 for 50 meters, and
10 for 100 meters. There were 41 net records and 5
pump records.

The species was not found south of 16° south nor
north of 34° north. There was no definite center of a-

bundance. The records of "occasional" were scat-
tered throughout the range. One of the records of
"common" was near Panama (station 35a), the other
two were northeast of Samoa (station 157).

The surface temperatures at the stations where the
species occurred at any depth varied from 18°.7 to
29°.4 C. The ranges of hydrographic conditions in situ
were as follows: temperature, 14°.4 to 29°.2 C; salinity,
29.7 to 35.9 o/oo; pH, 7.82 to 8.39; phosphate, 4 to 189
mg P04/m3.

This is apparently a strictly tropical species, per-
haps confined to the Pacific. Waters of low nutrient
content are apparently no barrier to it, as there were 5
records in water containing less than 10 mg P04/m3.
Type locality: Carnegie station 35.

Peridinium truncatum forma acutum n.f.
(Figures 40C, D)

Dimensions . Length of body ( 1_) 238 microns.
Length (h) 168 microns. Diameter (d) 168 microns. Di-
ameter (g) 98 microns. Width of girdle 6 microns. One
specimen measured.

Shape . Body shape close to average for species in
all respects except in the length of antapical horns and
theg/d ratio. TheJ/d ratio is 1.42. The h/d ratio is
1.00. The g/d ratio is 0.58. The r/g ratio is 0.46. The
angle a is 63°. Antapical horns more slender, with
pointed ends, the right more so than the left. The spec-
imen observed had broad intercalary zones, so that
there was a wider spread of the antapical horns than
otherwise would have been the case. Dorsoventral di-
ameter greater than in the main species. The angle a
is near the maximum for the species. In all other re-
spects the shape fits description of main species. Plate
pattern apparently similar in all details.

Distribution . This form was found only at station
104, in the western Pacific northwest of the Marshall
Islands, in May. It was collected in the 100- meter tow.
The hydrographic conditions in situ were: temperature.
25°.3 C; salinity, 35.3 o/oo; pH, 8.21; phosphate, 7 mg
P04/m3. Type locality: Carnegie station 104.

Peridinium pallidum Ostenfeld
(Figures 42, 43)

Peridinium pallidum Ostenfeld, 1899, p. 60. Ostenfeld.
1900, p. 58. Ostenfeld, (1903) p. 581. figs. 130, 131.
Cleve, 1900a, p. 17, pi. 7, figs. 21, 22. Jorgensen,
1905, p. 110. Paulsen, ld07, p. 14. Paulsen, 1908,
pp. 48-49, fig. 60. Broch, 1910b, p. 45, fig. 17.
Meunier, 1919, pi. 15, figs. 24-29. Lebour, 1925,
p. 134, pi. 28, fig. la-d. Peters, 1928, pp. 31-33,
fig. 7a-c.

Peridinium pellucidum Gran, 1902, p. 186.

not Peridinium divergens pallidum Karsten 1906, pi. 23,
fig. 13a, b.

Dimensions . Length of body, including right antap-
ical spine, (i) 94 (44-128) microns. Length (h) 78 (38-
107) microns. Transdiameter (d) 73 (35-98) microns.
Diameter (g) 45.9 (33-56) microns. Angle a 121°5
(105°-148°). Width of girdle 5 (3-6) microns. Eighteen
specimens were measured.

Shape . Body in ventral view roughly squarish In
outline, somewhat longer than broad. The h/d ratio is

FAMILY PERIDINIACEAE

33

1.07 (0.95-1.28). Epitheca almost triangular, with apex
more or less prolonged into apical horn, which may be
almost absent or as much as 2 girdle widths long. Hy-
potheca shorter than epitheca. Thus, the girdle is some-
what posterior. Hypotheca subtruncate with indentation
at sulcus. The two antapical processes thus formed can
scarcely be termed horns. Body well rounded in girdle
region. In apical or antapical view ovate, compressed
dorsoventrally. The s/d ratio is 0.68 (0.53-0.90). In
side view body also subovate. Girdle dextral, displaced
0.5 to 1.0 girdle width, not excavated, inclined (in side
view) at an angle of about 25°. No girdle overhang.
Ventral area angular in outline, extending from anterior
margin of girdle to antapex, and deeply embedded in
body. Sulcus lies to the left, overhung by the major body
plates. Flagellar pore oval in outline, centrally located
in ventral area and covered by the right accessory and
left sulcal lists (fig. 43B, C).

Plate pattern . Epithecal tabulation para, hexa. A-
pex has a ring platelet and a ventral apical platelet (fig.
43A, D). Four girdle plates. The first girdle plate is
wider than long and extends somewhat into sulcus (fig.
42H). Second girdle plate short and squarish. The third
girdle plate comprises most of the girdle and encircles
the body almost to ventral area on right side (fig. 42F).
Fourth girdle plate short and rectangular, about twice
as long as wide, located at distal end of girdle.

Ventral area composed of six plates: anterior, left,
posterior, posterior accessory, right, and right acces-
sory (fig. 42H). Anterior sulcal plate (as) long, extend-
ing from apical plate to anterior edge of flagellar pore.
At the pore it has an internal spongy structure com-
posed of prongs or forks which fit into similar struc-
tures on the left and right sulcal plates making an inter-
locked joint. Left sulcal plate (Is) forms left edge of
flagellar pore and its anterior end touches first girdle
plate. It has a thickened ridge along its right edge which
forms left edge of pore. Posterior sulcal plate (ps)
forms posterior part of ventral area and is almost U-
shaped. Its left arm very narrow and carries posterior
segment of left sulcal list. Its right arm lies posterior
to right sulcal plate (rs). The latter plate occupies
most of right side of ventral area and posterior half of
its left edge forms the right edge of flagellar pore. It
bears the thick right accessory sulcal list, which pro-
jects over the pore, as well as internal processes sim-
ilar to those in P. depressum . There is, however, no
detachable internal plate. Between the right and the
posterior sulcal plates, at the posterior edge of pore,
there is a very small irregular plate, the posterior ac -
cessor y sulcal plate. It is not more than two to three
microns long and thus of almost indeterminable shape.
Anterior to the right plate and opposite distal end of gir-
dle, there is a short rectangular plate, the right acces -
sor y sulcal plate . This plate has been found only in P.
pallidum , which was the only one investigated with a
right-handed girdle. It is possible that the presence of
this plate goes with the right-handed girdle, for in such
a displaced girdle either the right sulcal plate must be
longer or else there must be an additional plate to oc-
cupy the increased distance on the right side of the sul-
cus between the distal girdle end and the antapex.

Body wall . Surface of body plates covered with ir-
regular short ridges and tubercles. Pores scattered
over the major plates and the right, left, and posterior
sxilcal plates. Very irregular row of extremely small
pores in mid-line of girdle plates. Very small trans-

verse ridges may exiend from outer margins of girdle
plates toward middle. Intercalary zones common and
may be quite wide. Intercalary striae run across these.
Rabbeting membranes well developed and may be as
much as 2 girdle widths wide.

Lists. Girdle lists well developed, usually about 1
girdle width wide. Apical lists well developed, some-
times more than 1 girdle width wide, similar to those in
P. depressum but wider and more extensive (fig. 43A,
D). Apical list encircles apex; composed of 3 segments:
dorsal, right, and left. Right and left segments (r.a.l.,
l.a.l.) are attached to apical and ventral edges of second
and fourth apical plates and continue down ventral side
of body sometimes as far as girdle. In this case the
proximal segments of these lists are attached to second
and sixth precingular plates. Dorsal segment of the ap-
ical list (d.l.) attached to third apical plate and continu-
ous with lateral lists. Right lateral list (r.1.1.) and left
lateral list (1.1.1.) run down sides of body, frequently to
girdle, in which case their intermediate segments are
attached to first and third intercalary plates and the
proximal, or girdle, segments are attached to third and
fifth precingular plates (fig. 42B).

Sulcal lists are also well developed. Left sulcal list
extends laterally over sulcus, about 1 girdle width wide.
Its anterior segment attached to first postcingular and
continuous with posterior girdle list. Its posterior seg-
ment attached to left arm of posterior sulcal plate. Left
sulcal list terminates posteriorly in mid-region of this
plate (fig. 42H). Posterior sulcal list, which is attached
to sulcal margins of antapical plates, and the right sul-
cal list, which is attached to the second antapical and
fifth postcingular plates, are poorly developed except
where they converge and run up the right antapical spine.
(Fig. 42H). When intercalary striae occur alongthe right
border of the ventral area there is a weak development
of the right sulcal list on each edge of the zone. Right
accessor y sulcal list, which is attached to the right sul-
cal plate, is well developed and overhangs flagellar pore.

Other body lists may develop to a minor degree a-
long the sutures of the major body plates.

Spines . The two rounded processes of the antapex
are terminated by spines; the right usually longer than
the left. Length of right spine is 12.4 (7-17) microns.
Each spine composed of united short body lists. On the
right spine, one of these lists is continuous with left
sulcal list and one with posterior sulcal list. There are
at least two others which run out of the second antapical
plate with no relation to sutures. The left spine has four
or more short lists which bear no relation to sutures.
One of these articulates transversely with, and runs out
of, the left sulcal list. It can be disarticulated from it.
(Fig. 42H).

Variations . This species varies considerably in
size and shape. The length varies by three times (44-
128 microns). The compression of the body is rather
uniform in most specimens (g/d ratio is about 0.68) but
some specimens were found with more circular girdle
section, with g/d ratio as high as 0.90 (g/d ratio of clr- .
cle, of course, 1.00). Width of girdle is remarkably
constant in its absolute values, about 5 microns. This
is particularly noticeable in small specimens, where the
girdle is, then, relatively wide. The plate pattern in this
species seems to be in a fairly stable state. Only one
aberration was found. In this the fourth and fifth pre-
cingular plates were fused. The length of the antapical
spines varies in accordance with the variation in devel-

34

STUDIES IN THE MORPHOLCX3Y, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

opment of the lists of the body. The right spine varies
in length from 7 to 17 microns.

Comparisons . This is the only species of the para
group included in this report. It is of particular inter-
est to compare the ventral area of this species with that
of species of other parts of the genus. Previous inves-
tigators have considered Paraperidinium more closely
related to Metaperidinium than to Orthoperidinium. An
examination of the ventral areas of the representatives
presented in this report, however, indicates that Para -
peridinium is more closely related to the ortho group
than to the meta. Although the ventral area of P. palli -
dum is distinctive, it resembles in general that of P.
depressum more than that of P. crassipes or that of P.
truncatum . The entire ventral area is depressed in P.
pallidum, so that it does not take part in the major body
plate complex. In this respect P. pallidum resemblesP.
depressum . Similarly, the ventral area is bordered by
the primary sulcal lists rather than by the accessory
ones, even though the right sulcal list may be double in
specimens with intercalary zones. The ventral area of
P. pallidum differs from that of P. depressum signifi-
cantly only in the absence of the right internal sulcal
plate and in the presence of the right accessory sulcal
plate. Its only resemblance to that of P. crassipes and
to that of P. truncatum is in the relative position of the
sutures between the first and fifth postcingulars and the
antapical plates. These sutures join the ventral area a-
bout halfway between the antapex and the girdle, instead
of near the posterior end of the area as in P . depressum .

The absence of antapical horns does not seem to al-
ter the structure of the ventral area in any fundamental
way.

Of the species so far analyzed, this is the only one
in which the sutures between the girdle plates are so
near the ventral area, that is, in which the second and
fourth girdle plates are so short. In other species these
sutiires are in line with the sutures of the major body
plates.

Historical . This species is very closely related to
P. pellucidum (Bergh) Schutt and, in fact, may include
that species. If so, the name pellucidum has priority
(Bergh, 1881). In her comparison of these two species,
Lebour (1925) gives size and shape differences: P. pel-
lucidum . length 40-68 microns (without spine?), breadth
36-70 microns; P. pallidum , length 70-96 microns,
breadth not stated. In the Carnegie material the h val-
ues vary from 38 to 107 microns with no grouping of
the values that would suggest the presence of two spe-
cies or varieties. The diameters vary, similarly, from
35 to 98 microns. Only eighteen specimens were meas-
ured, however, and it is possible that additional materi-
al would indicate the possibility and desirability of sep-
aration. Lebour (1925) states that the compression is
very slight in P. pellucidum and gives a figure with cir-
cular girdle section (pi. 28, figs. 2c, 2d). In the Carne -
gie material the g/d ratio was found as high as 0.90,
and this was not correlated with small size but, on the
contrary, was found in one of the largest specimens of
the coUecUon. Lebour gives the theca as finely reticu-
late for P. pellucidum but gives no figures. Peridinium
pellucidum is supposed to be a neritic form (Lebour,
1925) and thus would not be expected to be found in the
Carnegie material.

In our opinion the existence of two separate forms
must be held in doubt until a further study is made of the
small neritic forms. If they are distinct from the form

found in the Carnegie material, then other characters
than size and shape must be found to distinguish them.

Distribution . Common in the northern North Atlan-
tic (Paulsen, 1908; Lebour, 1925). Reported from the
Mediterranean by Forti (1922). Rare in the Antarctic
(Peters, 1928). Not reported from the Indian Ocean by
Matzenauer (1933) nor from the Pacific by Bohm (1936).

In the Carnegie collection this species was found at
28 stations; 16 in the Atlantic and 12 in the Pacific.
There are 57 records of occurrence: 27 rare, 28 occa-
sional, and 2 common. It was found about equally at the
three levels although somewhat more frequently in the
upper levels, with 22 records for the surface, 20 for 50
meters, and 15 for 100 meters. There are 44 net rec-
ords and 13 pump records. It was found mostly in the
northern hemisphere, with only 1 station in the southern,
and from May to September.

In the Atlantic it occurred at most of the northern
stations and as far south as 34° north (station 17). In
the Pacific it was found at three series of stations: off
Japan (stations 113-114, 116-117); between San Francis-
co and Honolulu (stations 133-137); and in the western
series crossing the equatorial currents (stations 97-98,
101-102). There was no center of abundance; the rec-
ords of "occasional" were scattered over its range.

The surface temperatures at the stations where this
species was found at any depth varied from 8°.4 to 28°3C.
The ranges of hydrographic conditions in situ were as
follows: temperature, -1°.6 to 28°.3 C; salinity, 33.4 to
36.6 o/oo; pH, 7.87 to 8.47; phosphate, 3 to 99 mg
P04/m3.

Peridinium pallidum is probably a widespread spe-
cies of sporadic occurrence. It can endure a wide range
of hydrographic conditions, and factors limiting its pro-
duction are not indicated in the present data. It can de-
velop in low concentrations of nutrients, as is shown by
19 records in water with less than 10 mg P04/m3.

Family CERATOCORYACEAE Lindemann

Diagnosis . Shape angular to rounded, no prominent
horns. Epitheca rounded, hornless, spineless, usually
low. Hypotheca angular to rounded, usually bearing
prominent spines. Girdle anterior to equator, sinistral,
not concave, without overhang. Ventral area narrow,
depressed anteriorly; flagellar pore at anterior end.
Girdle and sulcal lists well developed. Ventral epithe-
cal pore present on a2. Plate formula: apical closing
platelet, 2ap, 2a, 5pr, 6g, 5-6po, Ip, lant, 5-6s. Marine.

Only one genus, which includes seven species.

Genus CERATOCORYS Stein
Diagnosis
See family diagnosis (monogeneric)

Description
Size . Length of body (i) varies from 38 microns in
C. gourretii to 99 microns in C. armata . Width at gir-
dle in ventral view (d) from 28 microns to 114 microns
in the same species, respectively.

Shape . Body angular in all species except C. gour -
retii . C. horrida being the most angular. At girdle, body
is squarish to circular or subovate. Girdle placed al-
most equatorially in C. armata and C. reticulata , in all

FAMILY CERATOCORYACEAE

35

otner species more anteriorly, reaching the most ante-
rior position in C. gourretii and C. horrida . The e/1
ratio varies from 0.16 in C. gourretti to 0.46 in C. re -
ticulata . Girdle displaced from 0.5 to 2.5 girdle widths;
its ends separated by anterior end of ventral area.

Angularity of body pronounced in lateral view, ex-
cept in C. gourretii , which is circular to ovate, mother
species epitheca triangular or triangular with truncated
apex. Hypotheca, in lateral view, squarish to triangular,
but always with an oblique shearing posteroventrally
(except in C. gourretii ) which displaces the posterior
end of the sulcus some distance from antapex, some-
times as much as half the distance to the girdle. In C.
bipes the shape characteristic of the genus somewhat
obscured by presence of two posterior lobes, one ven-
tral and one dorsal.

Greatest width of body is at girdle in all species ex-
except C. gourretii and C. horrida . In the former spe-
cies, this occurs about midway between girdle and ant-
apex, and in the latter species, just posterior to girdle.

In ventral view, also, body is quite angular in most
species. Epitheca dome-shaped to triangular in all spe-
cies, but may be very low in C. g ourretii and C . horrida .
Hypotheca triangular to squarish. Degree of "squarish-
ness" expressed by the angle /9. This angle was not
measured in C. horrida and C. g ourretii . as their later-
al edges are not straight, making accurate measure-
ments impossible. Fortunately, determination of this
angle is not necessary for the differentiation of these
species. Ceratocorys horrida is the most squarish of
the genus, and its antapex is the broadest; C. g ourretii
is rounded antapically. In other members the most tri-
angular is C. reticulata , with an average angle /3 of 37°.
The other species vary between this value and 15°.5,
which is found in C. skogsbergii .

Plate pattern. For plate formula, see family diag-
nosis (p. 32). Number of plates, twenty-nine, constant.
Apical pore covered by a closing apical platelet, as in
Gonyaulax ; a platelet not attached to any body plate.

There are four plates in apical region, but only two
of these may be considered apical plates, as the other
two do not touch the apical closing platelet (fig. 47C).
First apical squarish and surrounds left and dorsal edg-
es of platelet; second apical is an elongated ventral plate
and surrounds right and ventral edges of apex. First
anterior intercalary squarish and lies to the right of a-
pex between apicals 1 and 2. Second anterior intercala-
ry, like second apical, very narrow and lies along left
edge of second apical although it does not touch apex;
bears ventral epithecal pore.

The first three precingular plates occupy the first
three quadrants of the epitheca, and the fourth and fifth
occupy the fourth quadrant (fig. 44B). Fifth precingular
is smaller than the rest and lies posterior to second an-
terior intercalary and second apical plates.

There are six girdle plates of approximately equal
length.

There are five or six postcingulars; when five,
there is an extra plate in the sulcus, the homologue of
the first postcingular. For this reason the numbering of
the plates is kept uniform in all species, so that in the
species with only five apparent postcingulars (C. gour -
retii and C. skogsbergii ) the extra sulcal plate is des-
ignated postcingular 1. Postcingulars 1 and 2 are small
and always separated from 3 by a prominent list. Post-
cing\ilars 3 to 6 are large and comprise, along with the
antapical plate, the main Iwdy of the hypotheca. Poste-

rior intercalary lies to the left of sulcus between post-
cingulars 1 and 2, and antapical plate.

The single antapical plate occupies most of the ant-
apex but is displaced to the right so that the left edge of
antapex is formed by the turned-under edges of the third
and fourth postcingulars, which are much longer than
the postcingulars of the opposite side (fig. 47 A, B).

Ventral area composed of five or six plates (figs.
44 A, 58A): an anterior, a posterior, a left, a right, a
right accessory, and sometimes a left accessory which
is homologous with the first postcingular in other spe-
cies. When the flagellar pore is long, it may border the
right sulcal plate for half its length (C. horrida , fig. 47B),
but usually the left plate extends so far anteriorly that
the pore is quite remote from the right plate (C. aultii.
fig. 56A).

The plate pattern in Ceratocorys is remarkably con-
stant. In the main body plates practically no variations
were found. This is in striking contrast to the condition
in the genus Peridinium . where there are interspecific
differences as well as variations within the species. In
the ventral area of Ceratocorys there are variations to
be described below, but the number of plates is constant.

Body wall . Surface smooth to rugose and pitted in
all species except C. reticulata , which has a heavy retic-
ulation. Girdle with two rows of pores. Pores also oc-
cur in sulcal plates and in main body plates. In C. retic -
ulata pores not demonstrated, but probably present.

Flagellar pore approximately on a level with distal
end of girdle. Apical "pore" covered by a platelet as in
Gonyaulax . Ventral epithecal pore about midway be-
tween apex and girdle on riglit edge of second anterior
intercalary plate near its posterior end. This also re-
calls Gonyaulax .

Lists. Girdle lists attain their greatest width in C.
horrida . Usually with short, strengthening ribs running
radially. In addition to these ribs other heavy rlbllke
structures may be seen when the specimen is viewed in
apical or antapical aspect. These are not girdle list
ribs, but transverse girdle lists seen on end (figs. 49E,
54C). They are attached to the girdle, are spaced at
fairly regular intervals, and may attain a width exceed-
ing 1 girdle width and divide the girdle into a series of
chambers.

Lists may be developed at the borders of all plates
and, in addition, on the surface of the antapical plate.
Lists of C. horrida particularly wide and prominent.
Two lists are especially important: a list extending veh
trally from right edge of po3, the ventral body list ; and
one extending dorsally from dorsal edge of po4, the dor -
sal bod y list. In C. horrida and C. gourretii these bear
prominent spines.

In addition to these two lists and to the posterior
clngular list, there are, on the hypotheca, four nonspin-
ulate lists. The right sulcal list runs along left edge of
po6 and is continuous with distal end of posterior girdle
list. The left sulcal list is attached along right edge of
pol or po2 and of posterior intercalary plate, joining
posterior cingular list anteriorly and, sometimes, con-
tinuous with list of ventral antapical spine posteriorly.
The right lateral and left lateral lists run from posteri-
or cingular list down lateral sides of body a short dis-
tance; the former list at ventral edge of po5, the latter
at ventral edge of po4. These two lists may be absent.

Lists of the epitheca more variable than those of
other parts of body. In general there is a list for each
suture, although in old specimens the list may not be im-

S6

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PEMDINIALES

mediately adjacent to the suture.

Spines . Prominent hypothecal spines are a charac-
teristic of the genus. All species bear them on the antapi-
cal plate, and two species, C. horrida and C. gourretii,
have, in addition, a dorsal and a ventral spine. Dorsal spine
produced in dorsal body list and ventral spine in ventral
body list. Antapical plate normally bears two spines in
C. bipes , three in C. skogsbergil and C. gourretii , and
four in C. horrida . C. armata , C. reticulata , and C. aul -
til. When four spines are present, they occur at the four
edges of the antapical plate. When three are present, it
is the spine of the right corner that is absent; when two,
the spines of the right and left corners are absent.
Smaller spines, representing thickenings in various
body lists, may occur. There are "brushes" in the long
spines of C . horrida and C. gourretii ; in the other spe-
cies spines smaller and usually simple.

The spines of Ceratocorys are formed on the plan
of the junction of four lists and are not hollow as has
frequently been reported in the past. Each spine, when
viewed on end, presents the form of a cross (fig. 491, K).
This effect is more pronounced at the base of the spine,
where the lists are wider, but is evident to a certain ex-
tent even at the tip. On the antapical spines the lists are
frequently quite short, not running onto the body to any
extent (figs. 47, 58); but in other cases they may extend
to adjacent spines to join with their lists (figs.49G, 59D).
Lists of dorsal and ventral spines (C. horrida and C.
gourretii ) are more extensive. The anterior member of
each runs up to, and joins with, the posterior girdle
list. The "brushlike" or "featherlike" effect present-
ed by the distal half of these spines is due to the forma-
tion of side ribs or riblets from the center of the spine
along each of the four lists. This structure gives a very
dense appearance to outer parts of spines. There is, in
addition, a thickening where the four lists converge,
forming a sort of solid shaft, and a similar thickening at
the base of the spines where these join the body. This
thickening is especially pronounced distally, usually
forming a club-shaped mass on which the riblets are
superimposed.

The four elements of these spines cannot be sepa-
rated; each is an integral part of the whole. The spines
do, however, occasionally break off. Specimens have
been found with stubs of spines and with only the thick-
ening at the base remaining (figs. 49H, 59D). Spines
have been observed in the process of breaking off. In
such cases no separation of the four lists could be ob-
served; there was a shear transverse cleavage. Wheth-
er this is autotomy representing an adjustment to a
change in external environment, as Kofoid (1908) has
suggested in the case of Ceratium . is impossible to say.

Although these spines occur approximately along
sutures, they do not in any case run at the very edge of
a plate. There is always a zone between the base of the
spine and the actual suture. This is true of most of the
nonspinulate lists of the body as well, except in very re-
cently divided individuals. In such individuals, however,
the spines on the new moiety have not yet developed.

Reproduction

Binary fission is the only type of reproduction defi-
nitely known in the genus (see p. 36). Daughter cells
with one moiety undeveloped were found in C. horrida .
C. armata . and C. gourretii . The line of fission is ir-
regularly oblique, to the right of the longitudinal axis in

the epitheca and to the left of it in the hypotheca. To the
right moiety on the epitheca go precingulars 3, 4, and 5.
The fission line runs to the left of the flagellar pore, so
that the right moiety gets all the sulcal plates except the
anterior. It receives also postcingulars 5 and 6 and the
antapical plate (figs. 48, 53C).

Methods of Study

As an aid to defining the species of this genus, cer-
tain body dimensions were utilized. These are illustra-
ted in figure 45. All measurements of the body were
made with the specimen presenting the full ventral view.
The length of body ( 1_) was measured from the apex of
the body, excluding the lists, to the most posterior part
of the body, excluding the spines and lists, which, in this
view, is near the dorsal part of the specimen. The di-
ameter of the body at the girdle (d) is self-evident. The
relative length is expressed by thej/d ratio. The height
of the epitheca (e) was measured from the apex of the
body to the proximal end of the girdle at its anterior
edge. This dimension is always expressed as a fraction
of the body length (e/1. ratio). The angle ;6 is the angle
which the left contour of the body makes with the longi-
tudinal body axis, A-B. This angle gives a measure of
the amovint of narrowing of the body posteriorly.

Historical Review

The genus was first reported by Stein (1883), who
figured C. horrida in several views. The larger plates
of the theca were distinctly shown and the attachments of
all the six spines correctly indicated. The pattern of the
major plates is easily established from Stein's figures.

In the same year this species was described and
figured by Gourret (1883) under the name Dinophysis
i ourdanii . which later became attached to another spe-
cies, C. gourretii Paulsen (see p. 43). Schutt (1895) re-
ported a third species under the name Goniodoma acumi -
natum var. armatum ; and Cleve (1903) reported another
species under the name Goniodoma bipes . These last
three species were later ascribed to their proper genus
by Kofoid (1910), who appreciated the resemblances of
their plate patterns to that of Ceratocorys horrida Stein.

Murray and Whitting (1899) figured, under Cerato -
corys spinifera . a species of Gonyaulax and a species of
Ceratocorys . The latter species was renamed C. magna
in the revision of the genus by Kofoid. This revision,
thus, included five species. We owe to Kofoid the proper
allocation of all these forms to the genus Ceratocorys .
He did not figure any of the species, however, and did not
analyze the sulcal plate pattern.

Following Kofoid's (1910) revision, only one possi-
bly valid species has been introduced, viz., Ceratocorys
kofoidii Paulsen (1931, p. 36, fig. 22A-C). This species,
which is related to C. gourretii . was not found in the
Carnegie collections. Paulsen's sketches do not furnish
much more than the general body outline. He gives the
length as 115 microns. This exceeds the length of any
specimen of the genus Ceratocorys which the author has
ever measured, the longest being a specimen of C. arma-
ta, which measured 99 microns. This size can best be
appreciated if we contrast it with that of C. gourretii ,
which is the smallest species of the genus, and has a
length of 49 (38-62) microns. In Paulsen's description
of C. kofoidii it is stated that that species is related to
C. gourretii. that it differs in the less rounded form.

FAMILY CERATOCORYACEAE

37

higher epitheca, and absence of wings between the spines.
There is no comment on the extraordinary size, which,
if correctly given, would be the outstanding character-
istic of the species.

The true relationships of this species cannot be de-
cided until the morphology is known in detail. The spe-
cies probably belongs to the subgenus Protoceratocorys.
Ceratocorys kofoidii has not been treated elsewhere in
this report because of the imperfect knowledge of its
thecal morphology.

The present report includes seven species, three of
which are new. One of Kofoid's (1910) species has been
listed as uncertain. Furthermore, the species have
been arranged into two subgenera, the first attempt at a
subgeneric division of Ceratocorys so far made.

Systematic Position

Ceratocorys is probably most closely related to the
genus Goniodoma . This is indicated especially by the
number of plates in the two genera and by the patterns
of their ventral areas (see p. 6).

Ceratocorys is characterized by 29 plates, the
smallest number found among the genera investigated in
this report (see p. 7). The number of epithecal plates,
including the apical closing platelet, is only 10; and the
number of hypothecal plates is only 8. There are 6 gir-
dle plates and only 5 sulcal plates. Goniodoma agrees
with Ceratocorys In all these particulars except in the
number of epithecal plates, this being 11 instead of 10.

The actual relationship of these two genera is prob-
ably not so close as the agreement in the number of
plates suggests. For instance, although the number of
hypothecal plates is the same, the tabulation is quite
different: Ceratocorys has 6 postcingulars (2 of which
are minute), 1 small intercalary, and 1 antapical; Goni -
odoma has 5 postcingulars (subequal in size), no inter-
calaries, and 3 antapicals.

The relationship of Ceratocorys to Goniodoma is
perhaps better demonstrated by the tabiilations of the
ventral areas, a fact particularly evident from the spe-
cies of Ceratocorys with a short flagellar pore, such as
C. armata (cf. figs. 1, 53). The pattern of Ceratocorys
approaches that of Goniodoma more than that of any oth-
er genus investigated, but differs from it in the follow-
ing features: in Goniodoma the sulcal ring is complete;
the posterior sulcal plate touches the pore; and the left
sulcal plate is large and forms the left side of the pore.

The ventral areas of these two genera further agree
in their simplicity of contours, although in Ceratocorys
the area is narrower and there is a very definite depres
sion of the left side to form a sulcus, whereas in Gonio -
doma the area is almost flat and a sulcus proper is ab-
sent.

In the presence of the ventral epithecal pore, Cera -
tocorys resembles not only Goniodoma but also Gonyau -
lax and other related genera. Since there seems to be no
uniformity among the various genera as to which plate
bears this pore, the position of this structure in Cerato -
corys may be of no value in indicating relationships.

Ceratocorys is not closely related to any genus oth-
er than Goniodoma (see p. 8).

Relationships of the Species

In a discussion of the Interspecific relationships,
we have to deal with the following morphological char-
acters: degree of angularity of body; bipedal hypotheca;
number of major hypothecal plates; number of sulcal
plates; number of hypothecal spines; presence of dorsal
and ventral spines; and presence of brush spines.

On the basis of the most fundamental of these char-
acters, the difference in plate pattern, we can group the
species into two subgenera: Protoceratocorys n.subgen.
and Euceratocorys n.subgen. Protoceratocorys has pol •
in the sulcal complex, so that there are 6 functional sul-
cal plates and only 5 postcingulars. Euceratocorys has
pol definitely in the postcingular series, so that there
are 5 sulcal plates and 6 postcingulars.

Protoceratocorys includes two species: C. skogsber -
gii and C. gourretii . Ceratocorys skogsbergii has an an-
gular body and no dorsal or ventral spine; C. gourretii
has a rounded body and dorsal and ventral brush spines
as well as four antapical brush spines. It is thus evident
that the two species of this subgenus are distinct.

Euceratocorys includes five species: Of these C.
horrida is isolated by being the only one with dorsal and
ventral spines, and brush spines. It is further separated
from the other species of the subgenus by its angular
body, extreme development of lists, and low epitheca.

Ceratocorys bipes is unique in its bipedal body shape
and in the presence of only two antapical spines. Cera -
tocorys aultii is a small species with four antapical
spines and with body little compressed posteriorly.
Ceratocorys armata and C. reticulata are the only two
species of the genus which show close mutual relation-
ships. They are both compressed posteriorly and have
three or four antapical spines.

The evolution in this genus, thus, has been very di-
vergent (see fig. 46). The ancestral form of the genus
probably was small, spherical, and with four simple ant-
apical spines. If this assumption is correct, there has
been, in the subgenus Protoceratocorys, the development
of the angular body and reduction of spines in C. skogs -
bergii ; on the other hand, there has been a retention of
the primitive body shape but development of brush and
dorsal and ventral spines in C. gourretii, the two spe-
cies having separated at an early time.

Of the five species in the subgenus Euceratocorys,
C. aultii may be considered the most primitive, having
four antapical spines and rather rounded body. Cerato -
corys armata and C. reticulata have developed only in
size and toward a more pointed antapex. Ceratocorys
bipes represents a trend toward bilobed antapex and loss
of all but two spines, which are somewhat more devel-
oped than in the primitive species. Ceratocorys horri -
da has reached the highest development of angularity of
body and development of spines and Usts. It probably
was separated from the primitive form at an early date.

It win be noted that the tendency to develop dorsal
and ventral spines is correlated with the tendency to de-
velop brush spines of considerable length. These devel-
opments occur in both subgenera: in the very small ro-
tund species, C. gourretii, and in the large angular spe-
cies, C. horrida . This must be considered convergence.

38

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

as the plate patterns of these two species exhibit sub-
generic differences.

Ceratocorys Is probably a very old genus, a conclu-
sion suggested by the clear-cut definition of its species
along divergent lines, and by the high degree of con-
stancy of the species. Ceratocorys hor r Ida and C . ar ma -
ta are the most variable units. It should be noted, how-
ever, that their variations are not in the nature of tran-
sitions toward the other species of the genus.

Artificial Key to the Species of Ceratocorys

A. Prominent dorsal and ventral spines present as well
as antapical spines B

A. Prominent spines developed only on the antapical
plate C

B. Small rotund species, diameter 28-55 microns . .
C. gourretii

B. Large angular species, diameter 43-92 microns . .
C. hor r Ida

C. Hypotheca greatly compressed laterally toward the
antapex, angle /3 usually greater than 22° ... D

C. Hypotheca not greatly compressed laterally toward
the antapex, angle d less than 22° F

D. Antapex projected into 2 lobes, antapical spines 2 .
C. bipes

D. Antapex not projected into 2 lobes, antapical spines

3 or 4 E

E. Surface pitted, J/d ratio usually greater than 1.00 .
C. armata

E. Surface coarsely and heavily reticulated, J/d ratio
less than 1.00 C. reticulata

F. Antapical spines 4, postcingular 1 clearly visible in
ventral view C. aultii

F. Antapical spines 3, postcingular 1 scarcely or not at
all visible in ventral view .... C. skogsbergii

Subgenus EUCERATOCORYS n.subgen.

Sulcal plates five; postcingulars six. First postcin-
gular plate clearly evident in ventral view without dis-
section, overhangs flagellar pore. Type species: C.
horrida Stein.

Ceratocorys horrida Stein
(Figures 47-50)

Ceratocorys horrida Stein, 1883, p. 20, pi. 6, figs. 4-11.
Schutf, 1895, pi. 6, figs. 25 (1), 25 (2). Murray and
Whitting, 1899, in part, p. 329, pi. 30, fig. 5b. Oka-
mura, 1907, pi. 4, fig. 25a-c. Kofoid, 1910, pp. 180-
181. JSrgensen, 1911b, p. 146. Forti, 1922, p. 78,
fig. 73. Lindemann, 1925, pp. 99-101, figs. 13-19.
Mangin, 1926 (1922), p. 71. Dangeard, 1927c, pp.
342-343, figs. 7a, 8a-c. Issel, 1928, p. 273. Pavll-
lard, 1916, p. 24, PavlUard, 1931, pp. 100-101, pi.
3, figs. 17A, 17B. Paulsen, 1931, p. 35. Matzenau-
er, 1933, p. 452, figs. 20a-20c.

Dinophysls jourdanl Gourret, 1883, p. 79, pi. 3, fig. 55.

? Ce ratochorris trldentata Daday, 1888, p. 103, pi. 3,

fig. 3.
Ceratocorys horrida var. longlcornls Lemmermann,

IMS, p. 356, 371.

Ceratocorys horrida forma trldentata Entz, 1902, p. 139,

— ^rst.

Ceratocorys horrida var. africana Karsten, 1907, p. 419,

— Trrs^TTigirr^.

Ceratocorys horrida var. extensa Pavillard, 1931, p'. 101.

Matzenauer, 1933, pp. 452, 497, fig. 20d.
? Ceratocorys hirsuta Matzenauer, 1933, p. 453, fig. 23.
Peridinium globulus I lapsus pennae], Lindemann, 1925.

p. 99.

Dimensions . Length of body Q) 69 (38-97) microns.
Diameter of body at girdle in ventral view (d) 67 (43-92)
microns. Greatest diameter of body in this view usually
just posterior to girdle. Eighty-four specimens meas-
ured.

Shape . Body usually longer than broad. The J/d
ratio is 1.07 (0.87-1.35). Epitheca low, dome-shaped.
The e/l_ ratio is 0.24 (0.14-0.31). In apical or antapical
view, body squarish to circular at girdle. Girdle dis-
placed about 1 girdle width. Hypotheca very angular,
four -sided, usually somewhat constricted in the middle.
Antapex broad, sometimes nearly as broad as girdle
region, making sides almost parallel. Body longer on
left side than on right (fig. 47B). Posteroventral shear-
ing quite marked (fig. 47D, E). The angle 3 was not
measured for this species because the lateral edges of
the body were not sufficiently straight to allow an accu-
rate measurement.

Plate pattern . Second anterior intercalary narrow
and sometimes quite hidden between high lists sur-
rounding it, so that its presence can be determined only
by dissection. First anterior intercalary may or may
not be indicated by lists. Left sulcal plate very small
and placed posteriorly, so that the flagellar pore is long
and borders the right sulcal plate for half its length.

Body wall . Thecal wall regularly covered withpro-
noimced pits except in intercalary zones. In these zones
there is an irregular and variable scattering of pores
and, sometimes, pits and ridges. Ventral epithecal pore
always present although difficult to demonstrate because
it is placed between high lists surrounding second ante-
rior intercalary plate.

Lists. All body lists well developed. Girdle lists
very extensive, their width usually exceeding five times
the girdle width and sometimes almost half the diame-
ter of body. These lists are strengthened by many nar-
row irregular ribs, which usually run in from the edge
of the list (fig. 47C) but may occur in the center of the
list or run out from the body as well (fig. 49B). Poste-
rior girdle list usually has fewer of these ribs than the
anterior (cf. figs. 47 A, 4C). Girdle transverse lists well
developed (fig. 49E). Right sulcal list usually clear of
spines. Lists of body spines well developed; those of
antapical spines may or may not join with each other.
Body lists of epitheca about 0.5 girdle width in height.
Those along the sutures of the precingulars run out onto
the girdle Ust (fig. 47C).

Spines . The long brush spines in this species are
very striking and characteristic. There are four antap-
icals, one dorsal, and one ventral spine. They average
about 66 microns in length, or about as long as diame-
ter of body, but may attain a length of 120 microns. All
spines have "brushes" on their distal half which in
some cases, in heavily sculptured individuals, extend to
the body (fig. 49B). Structure of brushes described on
page 34.

Reproduction . Fission line typical of genus (p. 34).
Since the ventral and dorsal spines are attached to the
third and fourth postcingulars, which belong to the left
moiety, and since the antapicals belong to the antapical
plate, which goes with the right moiety, there is a great

FAMILY CERATOCORYACEAE

39

discrepancy in the appearance of the two daughter cells
immediately after fission (fig. 48A-I). These new spec-
imens have frequently been mistaken for taxonomic u-
nits (see under "Historical," below).

Reproduction may, possibly, take place by the pro-
duction of autospores. One specimen was found in sam-
ple 284, station 50 (fig. 50), which indicated that the en-
tire shell was newly formed, and similar specimens
were found in sample 563, station 95. The walls of the
first specimen were very thin, the pores were small
without pits, the lists were embryonic, and the spines
were absent. A slight indication of the formation of two
of the antapical spines was found in the usual position.
The size was normal for the adult. This specimen
strongly suggests that ecdysis of the shell occurs in this
species and that one or more new individuals are formed
from the old protoplast with the formation of entirely
new shells.

Variation . Although the size of the specimens of the
Carnegie material varied, these specimens represented
a homogeneous group and no separations of a taxonomic
nature could be made on this basis. The same held true
for the length of spines. Figure 51 shows the distribu-
tion of the frequency of various horn lengths in Carne -
gie material. It is evident from this that, so far as horn
length is concerned, only one species can be detected.
Lemmermann (1899) described var. lor^icornis as hav-
ing a horn length of 60 microns and Pavillard (1931) de-
scribed var. extensa with horns 120 to 130 microns long.
Sixty microns is near the average for this species in
Carnegie material (fig. 51). There are not, however, e-
nough data in the 120- micron range to test the validity
of Pavillard's var. extensa . Short-horned forms are
shown in figures 49D and F; long-horned forms in fig-
ures 49A, C, and G.

There is considerable variation in the thickness of
the thecal walls, in the thickness of the lists and spines,
and in the ornamentation of the body generally. One fre-
quently finds strongly sculptured individuals like that
shown in figure 49B. There is every gradation from this
to the more deUcate forms represented by figure 47.
These variants are not taxonomically distinct. The heav-
ily sculptured individuals apparently do not represent a
response to changed environmental conditions, as no cor-
relation could be found between their occurrence and
the hydrographic conditions. In four cases specimens
with thin and specimens with thick thecae were found in
the same sample; in five cases such specimens were
found at the same station. It is probable that the strong
ornamentation indicates age, and thus that there is a
continuous accretion of skeletal material in the course
of the life of the individual.

Occasionally supernumerary spines are developed.
These always appear in already existing lists, usually in
the spine lists as double spines (fig. 49C, F). Some-
times a spine falls to develop (fig. 49D). Lindemann
(1925, fig. 18) reports a specimen with only three antap-
ical spines. The absence of one spine in his figure 19,
however, may be caused by the particular view of the
specimen. Karsten's Ceratocorys horrida var. airicana
is a many-spined form.

Historical . Ceratocorys horrida was first estab-
lished by Stein (1883, p. 159). Stein's figxires are re-
markable for their clarity and accuracy and far excel
any illustrations of the genus since published.

Lindemann (1925, p. 101) apparently was not aware
of Kofoid's (1910) revision of the genus. Lindemann

stated that the tabulation in this species is uncertain and
variable, and that there are always four precingular
plates (there are in fact five) and one intermediate plate
which breaks up into a number of plates, the pattern be-
ing variable as indicated by the lists crossing this plate.
As shown by the present investigations, careful dissec-
tion reveals that the pattern in constant. The number
of plates in the apical region, as well as in all other
parts of the theca, does not vary, although the pattern is
not always indicated by the development of lists across
the apical region.

Ceratocorys tridentata Daday (1888) was accepted
by Entz (1905) and Kofoid (1910) as a short-horned form
of C. horrida . In the writer's opinion, howevfer, this
form cannot possibly belong to C. horrida because of its
elongated shape, high epitheca, and absence of ventral
and dorsal spines. Indeed, in the figure there is nothing
to indicate that it even belongs to the genus Ceratocorys .

Ceratocorys horrida var. longicornis Lemmermann
(1899) and probably C. horrida var. extensa Pavillard
(1931) are long-horned variants of no systematic impor-
tance. Karsten's (1907) C. horrida var. africana, fig-
ured with eight feathered and two simple spines, is also
a variant of no systematic importance (see above).

Dinophysis j ourdanii Gourret (1883) must be includ-
ed in the synonymy of C.- horrida (see p. 43 under C.
gourretii).

Ceratocorys hirsuta Matzenauer (1933) must be
placed in the list of doubtful species. In his descriptioa
Matzenauer states that the species is similar to C. ar-
mata but has longer, very tufted spines. His figure (p.
453, fig. 23), however, shows the body shape and girdle
lists of C. horrida . There are four antapical spines but
no dorsal or ventral ones. This specimen is possibly
the right daughter cell of C. horrida (see p. 36 and a-
bove).

Entz, as early as 1905, correctly described fission
in this species, opinions of later workers notwithstand-
ing. His indication of the skeletal fission line was cor-
rect except for details of the sulcal area.

The form to which Mangin (1926, p. 71) referred
was probably the left (two-spined) daughter cell, as
Dangeard (1927c) stated. Mangin's statement reads,
"La plupart des individus sont caracterises pardepuis-
santes cornes later ales aux angles de la valve inferi-
eure, mais il existe des formes divergentes dans les-
quelles deux Opines trfes developpees sont opposees I'une
i. I'autre, les autres Opines restant trfes minces."

Dangeard (1927c) understood the fission line of this
species and the significance of the two-spined speci-
mens. He presented iclear drawings of the left (two-
spined) moiety although he indicated the fifth precingu-
lar plate incorrectly as going to the left moiety.

Pavillard (1931) curiously refused to accept the two-
spined form as a division form in spite of the clear
drawings of the fission line by Entz (1905) and Dan-
geard (1927c) and the statement by Kofoid (1910) that
"short horns appear at fission in the younger parts of
the skeleton of otherwise long-horned forms." Pavil-
ard suggested, on the other hand, that these forms
might be identical with his var. extensa, which is char-
acterized by the length and straightness of the horns
rather than by any difference in their number.

Matzenauer (1933) apparently followed Pavillard's
interpretation of Mangin, but considered var. extensa
separate from Mangin's "forme divergente." He gives
figures under both titles.

40

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PEMDINIALES

Distribution . Ceratocorys horrida is a widespread
tropical and subtropical species. It has been found fre-
quently in the Atlantic (Schutt, 1895; Jorgensen, 1911b;
Dangeard, 1927c; Pavillard, 1931). It is common in the
Mediterranean (Gourret, 1883; Daday, 1888; Kofoid,
1910; Pavillard, 1916; Lindemann, 1925; Issel, 1928). In
the Pacific it was reported from the open North Pacific
by Lemmermann (1899), from San Diego by Kofoid (1910),
and from Japan by Schroder (1906) and Okamura (1907).
It also occurs in the Indian Ocean (Karsten, 1907; Mat-
zenauer, 1933).

In the Carnegie collection the species was found at
114 stations: 18 in the Atlantic, 96 in the Pacific (fig.
52). There were 360 records of occurrence; 154 rare,
162 occasional, and 44 common. It was found less fre-
quently with increase in depth, with 159 records for the
surface, 113 for 50 meters, and 88 for 100 meters.
There were 273 net records and 87 pump records. It
was found in both hemispheres and in practically all
months of the year.

This species occurred at almost all the Carnegie
stations in the tropics (fig. 52). In the Atlantic it oc-
curred at all but six stations south of 40' north; in the
North Pacific it occurred at all but one station south of
35° north; in the South pacific it occurred at all stations
north of 34° south except in the regions near South
America. It was absent in the Humboldt Current at
three stations near the Galapagos. It was rather uni-
formly distributed throughout its range; the records of
"occasional" and "common" were widely scattered
throughout the tropics.

The surface temperatures at the stations where it
occurred at any depth varied from 17 °5 to 29°. 5 C. The
ranges of hydrographic conditions in situ were as fol-
lows: temperature, 11°4 to 29°5 C; salinity, 29.7 to 37.0
o/oo; pH, 7.17 to 8.47; phosphate, 2to 189 mgP04/m3.
Although C. horrida is never abundant, it is one of
the commonest of the tropical peridinians. For this rea-
son it is an excellent indicator of tropical water. Ac-
cording to the Carnegie observations the species does
not endure any great lowering of the temperature and
consequently would not indicate water of tropical origin
very far from its source. For instance, in the North
Atlantic Drift the species drops out suddenly where the
water temperature at the surface falls below 19° C (sta-
tion 3). In the cold California Current it was not found
until the temperature had risen to 19°3 C (station 131).
South of Easter Island in the southeastern Pacific it a-
gain dropped out where the temperature fell below 19° C
(station 58). Off Japan it was not found in water with a
surface temperature below 23° 2 C.

These observations indicate that the active repro-
duction of C. horrida probably does not take place in
water of a temperature below 20° C and that the organ-
isms carried Into cooler regions seldom survive a tem-
perature below 19° C. In the region off South America
this species was conspicuously absent at 13 stations
where the temperature at the surface was above 19°. At
these stations the temperatures were mostly between
19° and 21° although at stations 71 to 74 the tempera-
tures were from 23°.5 to 25°3 C. The absence of C. hor-
rida from this series of stations can probably be attrib-
uted to the influence of the Humboldt Current, which is
composed of water of antarctic origin mixed with water
upwelling along the coast. The movement of this water
has a westerly component away from the continent. This
water is being constantly warmed as it progresses.

Even though it may reach a temperature sufficiently high
for Ceratocorys horrida , however, it does not contain
this species because of the lack of inoculation. Thus,
the eastern limit of the species in this region is pushed
westward by the drift from the edge of the Humboldt Cur-
rent. Inoculation probably takes place along this border
in an irregular and sporadic nature during fluctuations
of the dynamic conditions, probably through eddies from
the Easter Island region. That this type of inoculation is
probable is suggested by the isolated occurrence of C.
horrida at station 61a, with a surface temperature of
17°5, the only record where the temperature was below
19°. The water in that region must have been a local
mass very recently detached from the tropical mass to
the northwest.

Ceratocorys horrida is probably an important or-
ganism in the economy of the tropical and subtropical
seas. It was found throughout the regions where the
phosphate content of the water was less than 10 mg
P04/m3. At many of these stations the observed values
were less than 5. The nitrates, it is assumed, were e-
qually low. The nutrient requirements of this species
must be extremely low.

The wide range of salinities in which the species
was found indicates that the species is not very sensi-
tive in respect to the salinities found in oceanic condi-
tions. It occurred in the Panamic region in salinities as
low as 29.7 o/oo.

Ceratocorys armata (Schutt) Kofoid
(Figvires 53, 54)

Ceratocorys armatum Kofoid, 1910, p. 181.
Ceratocorys armata , Schiller, 1929, pp. 412-413, fig.

31a, b. Forti, 1922, p. 83, pi. 6, fig. 72.
Goniodoma acuminatum var. armatum Schutt, 1895, p.

153, pi. 9. figs. 32(1), 32(2). Lindemann, 1925, p.

98, figs. 5,6.
Goniodoma fimbriatum Murray and Whitting, 1899, p.

52S71)1. 27, fig. la, b.

Ceratocorys spinifera Murray and Whitting, 1899, p. 329,

pi. 30, fig. 6c.
Goniodoma armatum , Schmidt, 1901, p. 135.
Gonyaulax ~ fimbria.tum Schr5der, 1906, p. 329.
y Cerato"c"orys armata , Matzenauer, 1933, p. 453, fig. 22.

Dimensions . Length of body (J.) 79 (54-99) microns.
Diameter (d) 70 (47-93) microns. Greatest diameter of
body at the girdle. Thirty-five specimens were meas-
ured.

Shape . In ventral aspect body roughly ovate to kite-
shaped (fig. 53A). Thei/d ratio is 1.09 (0.97-1.24).
Epitheca triangular to high dome-shaped. The e/l_ ratio
is 0.38 (0.31-0.46). At girdle the body is squarish to
circular with a ventral depression. Girdle displaced
about 1.5 girdle widths. Antapex narrow, so that the
angle j3 is comparatively obtuse: 31° (22°-38°). Hypo-
theca cut off obliquely so that the ventral end of antapi-
cal plate is about one-third of the way to girdle from the
dorsal end. Thus, the body is much more angular in lat-
eral view than in the ventral aspect (fig. 53D).

Plate pattern . Right sulcal plate is much longer
than in other species and extends posteriorly for half its
length into a shoulder of the posterior sulcal plate (fig.
53). Left sulcal plate short, so that the right sulcal plate
touches the flagellar pore.

Body wall . Thecal wall regularly pitted on all major
plates except along the suture zones. In these zones

FAMILY CERATOCORYACEAE

41

secondary thickenings running into the lists may devel-
op with age. There are scattered pores in the sulcal
area, as is shown in figure 53A. Ventral epithecal pore
usually not evident without dissection.

Lists . Width of cingular lists 1.25 to 2.00 girdle
widths, somewhat greater ventrally than dorsally.
These lists may bear short delicate ribs in the middle
or, in heavily sculptured Individuals, may have strong
ribs running from the body to the edge of the lists. Gir-
dle transverse lists frequently very well developed (fig.
54C). Lists occur along all the sutures of body plates.
There is a heavy ridge running along the left edge of the
right accessory sulcal plate extending from the left pos-
terior corner of the fifth precinguJar plate to the flagel-
lar pore and along the right edge of the pore.

Spines . Dorsal and ventral spines absent. Antapi-
cal spines three or four (figs. 53E, 54B, D). One list of
ventral antaplcal spine usually continuous with left sul-
cal list. The right antapical spine near but not at the
junction of po5, po6, and antl. Dorsally there are two,
rarely one, spines. When two, these spines are joined
by a list. These dorsal antapical spines are independ-
ent, i.e., they are not attached to the marginal lists of
the antapical plate as is the case with the other species
of the genus. At various curvatures of the body lists,
particularly at apex and antapex, there are apparent but
not real spines, especially in strongly sculptured indi-
viduals.

Reproduction . Division is typical of the genus.
Both right and left daughter cells have been found. A
daughter cell with new right moiety is shown in apical
view in figure 53C.

Variation . There is the usual variation in the thick-
ness of the walls and extent of surface sculpturing due
to age. Figure 54A, and B shows a specimen in which
the entire theca, including the intercalary zones, is
composed of thick, heavily ornamented walls. The two
dorsal antapical spines may be situated near the cor-
ners of the antapical plate or more or less close togeth-
er (fig. 54D); or they may be fused into one in the cen-
ter of the dorsal side of this plate (figs. 53E, 54E). The
girdle lists may be entirely without spines or they may
have short, thickening ribs running from the outer edge
or may have heavy ribs extending from the body.

Historical . This species was first described by
Schutt (1895), 'who figured a form with two dorsal antap-
ical spines under the name Goniodoma acuminatum var.
armatum . Goniodoma fimbriatum Murray and Whitting
(1899) is identical with this species. The apical view
of Ceratocorys spinifera Murray and Whitting (pi. 30,
fig. 6c) probably also refers to this species. These au-
thors' apical view of a "mature specimen" (pi. 30, fig.
6d) may belong to this species. It is peculiar only in its
large size. It is 142 microns in diameter according to
the magnification given by these authors. The widest
specimen in the Carnegie collection is 93 microns, the
mean is 70 microns. Kofoid (1910, p. 182) described a
new species, C. magna , on the basis of this figure. It
does not seem desirable to retain this name among the
valid species, as there is always the possibility of a
mistake in magnification and there is no other feature
of this figure to distinguish it from C . 'armata . Kofoid
(1910, p. 181) was the first to bring C. armata under the
genus Ceratocorys, where it properly belongs. Linde-
mann (1925), however, was apparently unaware of Ko-

foid's (1910) revision and lists it under the Schuttean
designation (p. 98, figs. 5, 6). He states that the plate
pattern is a little uncertain and questions the position of
the form in the genus Goniodoma . He even suggests a
relation to the genus Phalacroma. Matzenauer's C. ar -
mata (1933, fig. 22) must be considered questionable.
The hypotheca is too long for this species; only two
spines are Indicated; and, all together, the figure gives
the impression of representing an undeveloped speci-
men.

Distribution . Ceratocorys armata is a widespread
tropical and subtropical species. It has been reported
from the Atlantic by SchOtt (1895), Murray and Whitting
(1899), Schmidt (1901), Pavillard (1931); from the Medi-
terranean by Schmidt (1901), SchrOder (1906), Kofoid
(1910), Pavillard (1916), Issel (1928), Lindemann (1925),
Schiller (1929), Forti (1922); from the Pacific by Schmidt
(1901), Lemmermann (1904), Kofoid (1910); and from the
Indian Ocean by Schmidt (1901), Schroder (1906).

In the Carnegie collection this species was found at
79 stations: 11 in the Atlantic, and 68 in the Pacific.
There are 163 records of occurrence: 94 rare, 60 oc-
casional, and 9 common. It was found less frequently
with increasing depth. There are 87 records for the sur-
face, 41 for 50 meters, and 35 for 100 meters. There
are 117 net records and 46 pump records. The species
was found in both hemispheres and in all months but
June. The species was rather widespread at the tropical
and subtropical stations (fig. 52). In the Atlantic it did
not occur north of 40° north; and in the Pacific it oc-
curred between 35° north and 35° south latitude.

The surface temperatures at the stations where the
species occurred at any depth varied from 19' to29°.4C.
The ranges of hydrographic conditions in situ were as
follows: temperature, 14°3 to 29°4 C; salinity, 30.0 to
36.8 o/oo; pH, 7.80 to 8.39; phosphate, 2 to 151 mg
P04/m3.

Ceratocorys armata was found almost entirely with-
in the range of C. horrida, and its distribution is prob-
ably limited by the same factors that limit the latter
species. It is a much rarer form than C. horrida , so
that its records of occurrence are not so continuous.
This does not necessarily mean, however, that its oc-
currence is sporadic. Its occurrence outside the range
of C. horrida was in the southeastern Pacific betwe.en
Easter Island and South America at stations 62, 63, and
64a, where the surface temperatures were between 19°
and 20°. This exception probably was due to a local in-
oculation of this general region similar to that of C. hor -
rida at station 61a.

The data indicate that C. armata Is more limited to
the warm water than is C. horrida . The species is not
found regularly enough within its range, however, to al-
low us to consider as really significant the negative rec-
ords along the limits of the distributional area. It oc-
curred in the North Atlantic Drift as far to the north as
did C . horrida , viz., to station 2, where the temperature
was 20°5. Beyond the California Current it did not ap-
pear until a surface temperature of 22°9 was attained;
off Japaniit did not occur where the temperature of the
surface water was less than 23° 9; and south of Easter
Island it was found as far south as station 57, where the
surface temperature was 19°0. It is not sufficiently
common to be of great value as an indicator of tropical
water; its presence is significant but not its absence.

42

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

Ceratocorys reticulata n.sp.
(Figure 55)

Dimensions. This is the largest species of the ge-
nus. Length of body Q) 93 (84-98) microns. Diameter
of body (d) 99 (86-114) microns. Greatest diameter of
body Is at the girdle. Four specimens were measured.

Shape . In ventral aspect the body is almost dia-
mond-shaped, somewhat truncated posteriorly (fig. 55A).
This species is unique in that the body width always ex-
ceeds the length; Vd ratio is 0.94 (0.86-0.97). Epitheca
subcorneal, the highest of any species of the genus. The
e/i ratio Is 0.42 (0.40-0.46). Thus, the girdle is nearly
equatorial. At girdle, body is nearly circular with a de-
pression ventrally (fig. 55B). The wide girdle region
and almost pointed antapex result in a comparatively ob-
tuse angle j9, the greatest of the genus: 37° (38°-39°).
The two sides of hypotheca nearly equal in length. An-
terior displacement of ventral side of antapex very small
(fig. 550). Girdle displaced about 1 girdle width.

Thecal wall . Surface completely covered with a
heavy reticulation except in parts of ventral area and on
the posterior intercalary plate. Pores could not be dem-
onstrated in the meshes of this network nor in the girdle.

Plate pattern . Left sulcal plate extends sufficient-
ly far forward so that the right sulcal plate does not
touch flagellar pore.

Lists . Girdle lists short, approximately 1 girdle
width wide, strengthened with regularly spaced ribs run-
ning from the body completely to outer edge. These ribs
are continuous with the girdle transverse lists and di-
vide girdle into a series of chambers. Body lists typi-
cal of genus. All sutures clearly indicated by low lists
or thick ridges. Right sulcal list usually supported by
several heavy spines (fig. 55C).

Spines . Dorsal and ventral spines absent. Antapi-
cal spines simple, three in number; one of them ventral
at posterior end of sulcus, the other two dorsal. The
latter are connected with the antapical lists by their own
connecting lists (fig. 55D).

Reproduction . Division stages were not found. In
the specimen shown in figure 55, however, the lists of
the right half of the body were not all well developed, in-
dicating a certain degree of immaturity of the specimen.

Variation . The species is constant. Variations in
size and shape have already been given above.

Distribution . In the Carnegie collection this species
was found at 30 stations: 1 in the Atlantic, 29 in the Pa-
cific. There are 41 records of occurrence: 36 rare and
5 occasional. The species was found somewhat more
often at 50 meters than at other depths, with 9 records
for the surface, 20 for 50 meters, and 12 for 100 me-
ters. There are 4 pump records and 37 net records.
The species was found In both hemispheres and from
September to May.

Ceratocorys reticulata Is a distinctly tropical spe-
cies. Although it occurred at scattered stations as wide-
ly separated as Guam and Panama, it was not found
north of latitude 30° north in the North Pacific nor south
of 18° south in the South Pacific (fig. 52). In the Atlantic it
occurred at 13° north, in the North Equatorial Current.

The surface temperatures at the station where the spe-
cies occurred^t any depth variedfrom20!4 to 29°5 C. The
ranges of hydrographic conditions in situ were as follows:
temperature, 19°5 to 29°.3C; salinity, 30.0 to 36.3 o/oo;
pH, 8.09 to 8.42; phosphate, 3 to 60 mg P04/m3. Type
locality: Carnegie station 28.

Ceratocorys aultii n.sp.
(Figure 56)

Dimensions . Length of body Q) 68 (63-71) microns.
Diameter (d) 61 (55-65) microns. Three specimens
were measured.

Shape . Similar in general appearance to C. skogs -
bergii, which belongs to the subgenus Protoceratocorys .
Slightly longer than wide. The^/d ratio is 1.11 (1.09-
1.15). Epitheca high dome-shaped to subcorneal. The
e/l_ ratio is 0.35 (0.30-0.38). Girdle displaced about 2.5
girdle widths. Body almost circular in apical view.
Antapex broad; angle j3 thus comparatively acute: 21°
(20°-21°). Posteroventral obliquity pronounced (fig.
56D). In specimens with wide intercalary zones, the
dorsal antapical spines are displaced ventrally so that
there is a flattening of the antapex dorsal to the spines
which produces a superficial resemblance to C. skogs -
bergii (fig. 56D).

Body wall . Surface regularly covered with small
pits. Intercalary zones covered with a faint network of
large reticulations. Ventral epithecal pore inconspicu-
ous. Pores scattered in sulcus (fig. 56A).

Plate pattern . Left sulcal plate extends anteriorly
so that the right plate is quite remote from flagellar
pore (fig. 56A).

Lists. Girdle lists of medium width; about 1.5 to
2.0 girdle widths wide. Strengthening ribs usually not
well developed. Transverse girdle lists, however, well
developed, as are sulcal lists. General body lists not
well developed.

Spines . Dorsal and ventral spines absent. Four
antapical spines at the four corners of antapical plate.
Spines simple, about 3 to 4 girdle widths long. The dor-
sal and left members connected by a common list (fig.
56A, B, D), as are sometimes the ventral and right
spines. Left sulcal list runs onto ventral antapical
spine. Ventral and left sometimes closely approximat-
ed. It is not unlikely that in some specimens these
spines may be fused into one spine, considering that this
condition is sometimes found in C. armata, of which
much more material is available.

Reproduction . Daughter cells were not found.

Distribution . In the Carnegie collection this species
was found at 15 stations, all in the Pacific. There are
21 records of occurrence, all rare. The species was
found more frequently with increasing depth, with 5 rec-
ords for the surface, 6 for 50 meters, and 10 for 100
meters. There are 14 net records and 7 pump records.
The species was found in both hemispheres; during Jan-
uary to May in the southern hemisphere, in September
and October in the northern hemisphere.

The stations at which this species was found are in
widely -scattered regions of the North and South Pacific
(fig. 52). Three of these stations are east of Guam;
four between San Francisco and Hawaii; four near the
Samoan Islands; one east of the Tuamotus; and three
south and east of Easter Island.

The surface temperatures at the stations where the
species occurred at any depth varied from 16°.9 to
29°.5 C. The hydrographic conditions in situ were as
follows: temperature, 14°.3 to 29°.3 C; salinity, 34.4 to
36.3 o/oo; pH, 8.05 to 8.39; phosphate, 3 to 46 mg
P04/m3.

Ceratocorys aultii is a rare, tropical species, prob-
ably widespread in tropical waters but seldom collected
because of its sparse population. Its greatest abun-

FAMILY CERATOCORYACEAE

43

dance may be below 100 meters, since in the Carnegie
observations its frequency of occurrence increased with
depth to that level. The species was found within the
geographic range of C. horrida , except in the southeast-
ern Pacific, where there were two stations (stations 62
and 65) outside that range. The correlation of its dis-
tribution with water of temperatures above 19° was clos-
er than in the case of C. horrida . Nowhere was C. aul -
tii found where the surface water had a temperature less
than 19° C. It can live in water of low nutrient content.
There are eight records of its occurrence in water con-
taining less than 10 mg PO^/m^. Type locality: Car -
negie station 57.

Ceratocorys bipes (Cleve) Kofoid
(Figure 57)

Ceratocorys bipes Kofoid, 1910, p. 183. Dangeard,

1927c, pT3l3, fig. 9a.
Goniodoma (?) bipes Cleve, 1903, p. 371, fig. 2a-d.
Ceratocorys (?) asymmetrica Karsten, 1907, p. 419, pi.

47, fig. 9a-d.

Dimensions . Length of body (1^) 83 (80-88) microns.
Diameter (d) 73 (70-77) microns. Six specimens were
measured.

Shape . Body longer than broad. The J/d ratio is
1.13 (1.04-1.24). Girdle placed well forward; ends dis-
placed about 0.5 girdle width. Epitheca low dome-
shaped. The e/i ratio is 0.28 (0.24-0.34). Hypotheca
irregular in shape; roughly squarish in lateral aspect
but subcuneate in ventral aspect. The angle (8 24° (17°-
28°). At antapex there are two bulbous swellings, one
dorsal and one ventral. Each is terminated by a long,
prominent spine, directed ventrally, giving the species
its characteristic appearance. Dorsal bulb medially sit-
uated and involves parts of po4, po5, and antl (fig. 57E).
Ventral lobe somewhat to the left of median line. It in-
volves posterior parts of the left side of sulcus and of
pi, as well as part of po3 and antl. Right side of sulcus
not involved in this lobe, so that the right ventral con-
tour of the body in right lateral view approximates the
typical Ceratocorys shape (fig. 57C).

Body wall . Thecal surface covered throughout with
circular pits except on parts of sulcus. Pores could not
be demonstrated in pits. Ventral epithecal pore incon-
spicuous.

Plate pattern . Second anterior intercalary narrow
and almost hidden between list ridges bordering it.
Ridge between as and ra rises to touch right edge of pol,
so that flagellar pore is completely arched over in its
middle. Left sulcal plate short, so that right sulcal
plate touches flagellar pore.

Lists . Girdle lists relatively short, about 1 girdle
width wide; strengthened by stout spines running out as
continuations of body wall, almost or entirely to outer
edges. These ribs are continuous with partitioning lists
or ridges on girdle plates. Surface of girdle may con-
sist of two rows of small chambers or, more often, of
one row of deep chambers with prominent partitioning
lists (fig. 57A). Sulcal lists and ventral body list are
quite wide (fig. 57C, D, F) and supported by several
ribs. Main body sutures usually evidenced by thick
ridges or wide bands of undifferentiated heavy thecal
material, the latter probably representing growth zones.

Spines . Dorsal and ventral spines absent. Antapi-
cal spines two; they occur at dorsal and ventral corners

of antapical plate, and appear as long, sharp spines, as
much as 4 girdle widths long. They are simple but
formed on the same principle as those of C. horrida
(p. 33). Ventral component of ventral antapical spine
usually continuous with left sulcal list.

Reproduction . Fission probably is typical of the ge-
nus although no recently divided forms were found.

Variation . This species is very constant as to size,
shape of body, and number of spines. One specimen was
found (fig. 57C), however, in which each antapical spine
was represented by two short spinelets.

Historical . This species was first described by
Cleve (1903) as Goniodoma (?) bipes. Later Karsten
(1907) hesitatingly placed it in the genus Ceratocorys ,
species asymmetrica . Kofoid (1910) placed it definitely
in its proper genus.

Distribution . Ceratocorys bipes is a rare tropical
species seldom reported. It was recorded once from
the Red Sea and Arabian Seas (Cleve, 1903), once from
the Indian Ocean (Karsten, 1907), and once from the
Atlantic (Dangeard, 1927c). It had not been reported
from the Pacific before the Carnegie investigations.

In the Carnegie collection the species was found at
22 stations: 1 in the Atlantic and 21 in the Pacific.
There are 31 records of occurrence: 29 rare and 2 oc-
casional. It was found more frequently with increase in
depth, with 3 records for the surface, 11 for 50 meters,
and 17 for 100 meters. The 2 records of "occasional"
were at 50 and 100 meters. There are 9 pump records
and 22 net records.

The single occurrence in the Atlantic was at station
2, in the North Atlantic Drift (fig. 52). In the Pacific the
species occurred at widely scattered regions, but all
records were well within the range of C. horrida . There
were 2 stations south of Japan, 2 north of Hawaii, 8 in
the equatorial currents of the central Pacific, and 9
between the Galapagos and Easter Islands.

The surface temperatures at the stations where the
species occurred at any depth varied from 20°.8 to
29 °4 C. The ranges of hydrographic conditions in situ
were as follows: temperature, 18°.2 to 29°.3 C; salinity,
34.4 to 36.4 o/oo; pH, 7.93 to 8.37; phosphate, 4 to 60
mg P04/m3.

Ceratocorys bipes is a rare tropical species, per-
haps widespread but seldom collected because of its
sparse numbers. It is strikingly restricted to the warm
tropical water masses, much more so than most other
species of the genus. Thus, although it was found off
Japan at latitude 34° north in water with a surface tem-
perature of 23°2 (station 112), it was not found near the
influence of either the California Current or the Hum-
boldt Current. It was found in the southeastern Pacific,
south of Easter Island, but the temperatures there were
above 20°. It can live in water low in nutrients; e.g.,
there were six records in water having a phosphate con-
tent less than 10 mg P04/m3.

Subgenus PROTOCERATOCORYS n.subgen.

Sulcal plates six, postcingulars five. Sixth sulcal
plate homologous with first postcingular of Eucerato -
corys . For this reason the designation pol is retained
for this plate. This plate is small and is turned down to
form the left edge of the sulcus along side of flagellar
pore, and is not evident in the ventral view of an intact
specimen. Type species: C. gourretii Paulsen.

44

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINLALES

Ceratocorys skogsbergii n.sp.
(Figure 58)

Dimensions . One of the smallest species of the
genus. Length of body ( 1_) 66 (63-69) microns. Diame-
ter (d) 58 (56-59) microns. Two specimens were meas-
ured.

Shape . Similar in general appearance to C. aultii
of Euceratocorys . Body longer than broad. The j/d
ratio is 1.15 (1.13-1.17). Epitheca of medium height,
with girdle placed well forward. The e/l_ ratio is 0.33
(0.32-0.34). Girdle displaced about 0.5 girdle width.
Body almost circular in apical view (fig. 58B). Hypothe-
ca squarish at antapex; somewhat constricted near mid-
dle. Antapex broad, so that sides of hypotheca do not
converge at a great angle with longitudinal body axis.
The angle 15.°5 (15°-16°), the smallest of any species
for which this angle could be measured. The postero-
ventral corner of antapex is truncated obliquely at an
angle of about 45° to longitudinal axis (fig. 58D). Dorsal
hypothecal plates (po4 and po5) extend to and around
antapex, forming part of the most posterior end of body.
Antapical plate alone forms the obliquity and is not
rounded so as to form antapex, as is the case in C. hor -
rida (fig. 47E).

Body wall . Surface covered with small pits. Inter-
calary zones may have small irregular markings and
pores. Ventral area variously ornamented with reticu-
lations and pores (fig. 58A). Ventral epithecal pore in-
conspicuous.

Plate pattern . Second anterior intercalary some-
times touches apex and thus becomes, actually, an apical.
It is usually wide enough to be quite evident.

Lists. Girdle lists small, about 1 girdle width wide.
Strengthening ribs regularly spaced, usually running out
from body wall. When the girdle plates are dissected
away from the body plates to which the girdle lists are
attached, an extremely thin membrane is seen to be at-
tached to the girdle plate. In intact specimens this
membrane lies in contact with the list. Transverse gir-
dle lists fairly well developed. Body lists, except the
ventral one, not well developed. Body sutures may or
may not be indicated by such lists. The ridge to the
right of flagellar pore rises to meet pol, forming an
arch over the posterior part of pore.

Spines . Dorsal and ventral spines absent. Antapi-
cal spines three; straight and simple, about 2.5 girdle
widths long, placed at dorsal, ventral, and left corners
of antapical plate. They were not connected by lists in
the specimens examined, although the left sulcal list ran
onto the ventral spine.

Reproduction . Evidence of fission was not found.

Distribution . This species was found at 10 of the
Carnegie stations, all in the Pacific. There are 11 rec-
ords of occurrence, all rare. The species exhibited a
tendency to be more common at the surface, with 5 rec-
ords for the surface, 4 for 50 meters, and 2 for 100 me-
ters. There are 2 pump records and 9 net records.

In its geographic distribution, this species was re-
stricted to the southern and western Pacific (fig. 52).
There was 1 station off Japan (station 113), 2 in the
North Equatorial Current (stations 91 and 100), 4 east
of Samoa, and 3 southwest of Easter Island.

The surface temperatures at the stations where the
species occurred at any depth varied from 22°. 8 to
28° 7 C. The ranges of hydrographic conditions in situ
were as follows: temperature, 21°5 to 28°.7 C; salinity.

34.7 to 36.2 o/oo; pH, 8.22 to 8.39; phosphate, 8 to 40
mg P04/m3.

This is a very rare tropical species. There are so
few records of its occurrence that no distributional cor-
relation would be significant. There were 2 records of
its occurrence in water with less than 10 mg P04/m3.
Type locality: Carnegie station 51a.

Ceratocorys gourretii Paulsen
(Figure 59)

Ceratocorys g ourretii Paulsen, 1931, p. 36.
Phalacroma" j ourdanii Schutt, 1895, p. 64, pi. 4, fig. 20,

1-4. Entz, 1902, p. 130, figs. 6-8. Entz, 1905, pp

111, 113, figs. 1-4.

Ceratocorys horrida, Murray and Whitting, 1899, p. 329,

pL 30, fig. 5a.
Phalacroma Ceratocorys Entz, 1902, pp. 135-144, figs.

ys

26, 33. Entz, 1905, pp. 120-127,'figs. 22-28, pp.

Ill, 134-142.
Ceratocorys j ourdanii Kofoid, 1910, pp. 183-185. Forti,

1922, p. 84, pi. 6, fig. 74. Dangeard, 1927c, p. 343,

fig. 7b. Pavillard, 1931, p. 101. Matzenauer, 1933,

p. 452, fig. 21.
not Dinophysis j ourdanii Gourret, 1883, p. 79, pi. 3, fig.

55 (=C. horrida Stein).
? Dinophysis g ales , Pouchet, 1883, p. 28, fig. G, no. 3.
? Dinophysis j ourdanii , Klebs, 1884.
? Dinophysis armata Daday, 1888, p. 193, pi. 3, fig. 6.

Dimensions . Smallest species of the genus. Length
of body (i) 49 (38-62) microns. Diameter (d) 42 (28-55)
microns. Greatest diameter of body in ventral view 48
(34-60) microns. Nineteen specimens were measured.

Shape . Body unique in its subspherical to obovoid
shape, with absence of the angularity characteristic of
other members of the genus. The pronounced curvature
of the body causes the anterior circumference of the gir-
dle to be considerably shorter than the posterior (fig.
59D, E, F, G). Body circular to subovate in apical view
(fig. 59B), always slightly longer than wide. The h/^
ratio is 1.22 (1.06-1.57). Angle ;6 not measured fortius
species because of curvature of lateral margins. Epi-
theca low dome-shaped, with girdle far forward as in the
genus Phalacroma, with which the species has been con-
fused. The e/l_ ratio is the smallest in any species of
the genus: 0.20(0.16-0.22). Greatest width of body a-
bout halfway from girdle to antapical margin. Girdle
displaced about 1 girdle width.

Body wall . Thecal wall regularly covered with very
small pits. Ventral epithecal pore conspicuous. In in-
tercalary zones the pits are either absent or fewer than
on original portions of plates (fig. 59H).

Plate pattern . Second anterior intercalary narrow
and hidden between lists. Sometimes no other plates are
indicated by lists except at left side of sulcus. First
postcingular reduced to a small triangular plate joining
anterior sulcal and second postcingular plates. It forms
left edge of flagellar pore. Second postcingular more
distally located than anterior sulcal plate and partly
overhangs the pore as the first postcingular does in the
subgenus Euceratocorys . Right accessory sulcal plate
long. Right sulcal plate comparatively short, so that it
barely touches flagellar pore (fig. 59A).

Lists . Girdle lists about 1.5 girdle widths wide,
strengthened by cross ribs running either from body or
from outer edge of lists. Partitioning lists on the gir-
dle not well developed. Right and left sulcal lists al-
ways quite evident, as are the lists bordering a2 and the

FAMILY GONIODOMACEAE

45

apical pore platelet. Along other sutures of body, lists
may be absent and dissection is necessary to determine
plate boundaries.

Spines . Dorsal and ventral spines present; antapi-
cal spines three. All spines have "brushes" as in C.
horrida . Antapical spines located at the ventral, dorsal,
and left corners of antapical plate. They lie almost in a
straight line because of the oblong shape of the antapical
plate (fig. 59C). Their dorsoventral lists are continuous
(fig. 59D). Autotomy of the spines is common. Figure
)9D shows a specimen with autotomy of the dorsal spine.

Reproduction . Two daughter cells with old left moi-
eties were found. These showed mature dorsal and ven-
tral spines, but the antapical spines were minute (fig.
59E, G).

Variation . There is comparatively little variation
in the shape of this species, although the size is varia-
ble. The greatest variation is in the spines, which may
be variously bent, long or short, single or double. Fig-
ure 59F shows a specimen with a double ventral spine
and with an extra, simple spine in the dorsal list. Some-
times the central core of the spine may not extend to the
body (fig. 15E, G). In such cases the cruciform struct-
ure of the spines is not developed.

Historical . This species was clearly figured by
Schiitt (1895, pi. 4, fig. 20, 1-4), who, however, confused
it with Dinophysis j ourdanii Gourret (1883). Schiitt as-
signed his specimens and Gourret's species to the genus
Phalacroma , under the name P. j ourdanii . Entz (1902,
1905) accepted this interpretation and, in addition, made
the rather strange suggestion that this species repre-
sented a transition between the genera Phalacroma and
Ceratocorys . Kofoid (1910) definitely recognized the
true generic relationship of the Schuttian species and
placed this form in the genus Ceratocorys . Jorgensen
(1911b), apparently unaware of Kofoid s revision, ex-
pressed the opinion that Schutt's species belongs to
Ceratocorys . Kofoid, however, accepted Gourret's fig-
ure as representing this form. In the writer's opinion
Gourret's species (pi. 3, fig. 55) is quite obviously C.
horrida Stein, reported in the same year. In this re-
spect the writer agrees with the opinion expressed by
Paulsen (1931), who proposed a new name, C. gourretii,
for the Schuttian species. This name should be accept-
ed, since the name j ourdanii must be relegated to the
synonymy of C. horrida . Klebs (1884) recognized the
similarity between Gourret's and Stein's figures, but be-
lieved that Gourret, rather than Stein, realized its true
relationship, and thus he preferred the name Dinophysis
j ourdanii for Stein's as well as for Gourret's species.
In regard to Gourret's figure, the length of the spines,
shape of the body, and width of the cingular lists mark
it off sharply from Phalacroma j ourdanii Schiitt and re-
veal its identity with C. horrida Stein. It resembles the
former species only in having five spines instead of the
six characteristic of C. horrida . The left antapical
spine, however, which is missing in Gourret's figure,
often extends laterally so that it is not visible in the
view represented in this figure.

The writer agrees further with Paulsen (1931) In the
allocation of the figures of Murray and Whitting (1899,
pi. 30, figs. 5a, 5b). Figure 5a represents C. g ourretii ,
and 5b belongs to C. horrida . Kofoid (1910, p. 185)
erred in his reference to figure 5a and omitted any ref-
erence to figure 5b.

Distribution . Ceratocorys g ourretii is a rare but
widespread tropical species. It has been reported from

the Atlantic by Schiitt (1895), Murray and Whitting (1899),
and Dangeard (1927c). Pavillard (1931) reported it from
the collections of the cruise of the Prince of Monaco in
the tropical North Atlantic at 78 stations during the
years 1887, 1895, 1902-1905, 1908-1910. In the Medi-
terranean it was reported by Entz (1902, 1905), by Forti
(1922), by Paulsen (1931), and from 19 stations by
Pavillard (1931). Matzenauer (1933) found it at 2 sta-
tions in the Indian Ocean and at 2 stations in the Red
Sea. Until the Carnegie investigations it had been re-
ported only once from the Pacific, at San Diego (Kofoid,
1910). The Carnegie collection has added many new
records for the Atlantic and Pacific.

In the Carnegie collection this species was found at
41 stations: 5 in the Atlantic and 36 in the Pacific.
There are 77 records of occurrence: 68 rare, 8 occa-
sional, and 1 common. The species was found more fre-
quently at the surface than at the lower depths, with 47
records for the surface, 16 for 50 meters, and 19 for
100 meters. There were 33 pump records and 44 net
records.

In the Atlantic this species was found at 1 station in
the North Atlantic Drift (station 16) and at 4 stations in
the North Equatorial Current. In the Pacific it was
widely distributed in the tropical regions (fig. 52). In
the western Pacific, hbwever, it did not occur north of
19° north. North of the Hawaiian Islands it occurred as
far north as 34° north. In the southeastern Pacific it
occurred as far south as 32° south. It was not found
within a thousand miles of either North or South Ameri-
ca in the Pacific.

The surface temperatures at the stations where the
species occurred at any depth varied from 22.°3 to
28.°7 C. The hydrographic conditions in situ were as
follows: temperature, 11°4 to 28.°7 C; salinity, 33.7 to
36.4o/oo; pH, 7.76 to 8.39; phosphate, 3 to 60 mgP04/m3.

Ceratocorys g ourretii is apparently a widespread
but rather rare tropical species. The Carnegie obser-
vations indicate that it is confined to purely tropical wa-
ter. It was never found at a station where the surface
temperature was less than 22.°3, so that it is restricted
to water warmer than in the case of any other species
of the genus. Its geographical distribution is, thus, much
more limited than that of C. horrida . The species can
develop in water poor in nutrients. There were 21 rec-
ords of its occurrence in water with phosphate content
less than 10 mg P04/m3.

Family GONIODOMACEAE Lindemann

Diagnosis . "Shape somewhat spherical to polygonal.
Apex present. Girdle quite or nearly equatorial. Ma-
rine forms, which are distinguished by three antapical
plates, three apical plates in typical representatives. Of
the antapical plates, two are ventral, one dorsal. Length,
as far as known, 40 microns to 94 microns. Only one
genus." (Lindemann, 1928, p. 94.)

Genus GONIODOMA Stein

Diagnosis . See family diagnosis (monogeneric).

Extent of the genus . The genus, at present, contains
only one well-authenticated species, G. polyedricum
Pouchet, which is the only one treated in this report.
Other species have been reported with very sketchy

46

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINLALES

drawings, e.g., G. ostenfeldli Paulsen (1904), or with no
drawings at all, e.g., G. crassa and G. reticulata Kofoid
and Michener (1911). None of these can be included in
this genus with full certainty until more adequate de-
scriptions or figures are available.

Comparisons . The genus Goniodoma is a distinct
unit with no close relatives (see p. 8). All regions of
the theca except the girdle are distinctive. The tabula-
tion of the epitheca is unique. Although other genera
have been reported with ten epithecal plates, none has
the combination of three apicals, no intercalaries, and
seven precingulars. The hypothecal pattern is almost
equally distinctive. It occurs elsewhere only in the ge-
nus Pachydinium Pavillard.

The ventral area substantiates the distinctness in-
dicated by the larger body plates. The sulcal plates are
only five and are comparatively simple and flat. The
ventral area is rather flat and there is no well-defined
sulcus. The flagellar pore faces ventrally, so that it is
completely unobscured in ventral view. The ventral
area, thus, must be considered primitive as compared
with the highly complex areas of Peridinium and Gon-
y aulax with their development of intricate plates, deep
sulcus, and elaborate lists.

As indicated on page 8, Goniodoma may be consid-
ered a primitive genus whose closest relative is Cerato -
cojys, although the two genera are quite widely separat-
ed.

Goniodoma polyedricum (Pouchet) Jorgensen
(Figure 60)

Goniodoma polyedricum Jorgensen, 1899, p. 33. Paulsen,
1907, p. 8. Paulsen, 1908, p. 33, fig. 42. Paulsen,
1931, p. 37. Lindemann, 1925, pp. 97-98, figs. 2-4.
Lebour, 1925, p. 90, fig. 26. Pavillard, 1931, p.
96. Matzenauer, 1933, p. 452.

Goniodoma poiyhedricum , iiorti, iy22, p. 85, pi. e, fig.

75.
Peridinium p olyedricum Pouchet, 1883, p. 42, pis. 20,

Goniodoma acuminatum Stein. 1883, pi. 7, figs. 1-16, pi.

8, figs. 1, 2. ButscWi, 1885, pL52, fig. 5a-c. Schfltt

1887, figs. 13-16. Schutt, 1895, pi. 7, fig. 31, 1-3,

pi. 8, fig. 30, 1-10. Schutt, 1896, p. 21, fig. 30.

Aurivillius, 1898, p. 98. Cleve, 1900b, p. 245.

Entz, 1905, figs. 65, 66. Wang and Nie, 1932, p.

295, figs. 7, 8.
Ggnyaulax p olyedra Okamura, 1907, pi. 5, fig. 35a-c.
? Peridinium acuminatum Ehrenberg, 1838, p. 254, pi.

22, fig. f^ "

Dimensions . Length of body (j.) 58 (40-93) microns.
Diameter (d) 65 (45-100) microns. Width of girdle 4 to
6 microns. Eighty-two specimens were measured.

Shape . Body usually somewhat wider than long. The
1/d ratio is 0.90 (0.77-1.19). Body almost circular at
girdle but otherwise very angular (fig. 60A, B, H). An-
gles occur at almost all major body plate sutures. Epi-
theca angular dome-shaped without apical horn although
apex is well defined. Hypotheca broadly truncate poste-
riorly; antapex between one-third and one-half as broad
as diameter of body at girdle. Girdle nearly equatorial
sinistral; displaced from 1 to 2 girdle widths; slightly
concave; no overhang. Girdle continues onto ventral
area, where its ends are turned sharply posteriorly.
Ventral area short, broad, and angular, with a short pro-
jection of the anterior sulcal plate into the epitheca.
Flagellar pore ovate, on right side of ventral area at

proximal end of girdle. It is evident in ventral view
without dissection. Sulcus only slightly developed.

Plate pattern . Formula: 3ap, 7pr, 6g, 5s, 5po,
3ant. The three apical plates are about equal in size
and surround the apical platelet, which covers apical
pore (fig. 60A). This platelet is oval in shape and is
placed at an angle of about 45° to the dorsoventral axis
of the body. Precingular plates of approximately equal
size except the ventrally placed first and seventh, which
are about half the size of the others. The six girdle
plates subequal in size with sutures symmetrically
placed (fig. 60A). Postcingular plates also approximate-
ly equal in size, as are the antapicals (fig. 60B). Sec-
ond antapical composes most of the truncate antapex.
The first and third antapicals are more ventrally placed,
and each bounds half of posterior margin of ventral area.

The ventral area composed of five plates: three
large posterior plates lying posterior to the girdle, and
two anterior ones representing extensions of girdle.
Anterior sulcal plate (as, fig. 60F, G, H) forms anterior
end and half right edge of flagellar pore and represents
the proximal extension of girdle into ventral area. It
has a limb extending into epitheca, posterior to prl.
The anterior cingular list is continued across it. The
left, posterior, and right sulcal plates are more or less
rectangular, of about equal size, and form greater part
of area. Left sulcal plate forms left edge of pore, the
posterior plate the posterior edge, and the right sulcal
plate is not in contact with the pore. Right accessory
sulcal plate forms an extension of the distal end of gir-
dle into ventral area. It has a narrow anterior limb
which extends to anterior sulcal plate to form the right
edge of pore. Thus, all sulcal plates border the pore
except the right.

Surface. Entire body wall, including that of girdle
and sulcal plates, covered with large pits regularly ar-
ranged. These have pores in their centers which, in
optical cross section, can be seen to extend through body
wall. Thickness of body wall extremely variable and
depth of pits varies accordingly. Girdle bears two to
four rows of pits with pores, although only two rows are
ordinarily visible in ventral or lateral view as outer
rows are on curved sides of girdle. There is a ventral
epithecal pore situated on the anterior margin of prl
(fig. 60D, H). This pore is peculiar in not being covered
by a platelet or surrounded by a ridge or list. Body
plates joined by rabbet membranes which are rather
narrow compared with those in Peridinium .

Lists. Cingiilar lists from 1.5 to 2.5 girdle widths
wide, always somewhat ornamented with spines and re-
ticulations, which are quite thick (fig. 60C). Posterior
list usually more heavily sculptured than the anterior
(fig. 60A, B). Each suture of main body plates marked
by a thick triangular list ridge. When these are viewed
along edge of body, they appear as thin lists because of
their transparency (fig. 60H, I). Along their outer mar-
gins they may be clear or bear reticulations. Proximal-
ly, however, they almost invariably bear large reticula-
tions or pits (fig. 60A, B, H). Lists surrounding ventral
area do not attain a greater development than that of the
body lists. No lists occur at sutures between sulcal
plates except between the left and posterior sulcal plates.

Variation . The size varies considerably. In our
material both the length and the width showed a differ-
ence of over 100 per cent between the smallest and
largest specimens. Shape of body more constant. Most
of the material had anj/d ratio less than 1.00; in only

FAMILY GONYAULACACEAE

47

2 of the 82 specimens measured was this ratio more
than 1.00, viz., 1.03 and 1.19. The broadest specimen,
with an_l/d ratio of 0.77, on the other hand, was connect-
ed with the mean by a continuous series of intergrades.
It was at first thought that the smallest specimens rep-
resented a distinct species, but when the frequency of
the width of all specimens was plotted, a primary mode
was found at 65 microns and a secondary one at 45-50
microns with so many records between that not even a
variety was indicated on this basis. The thickness of
the body wall and of the associated lists is variable;
forms with extremely heavy thecae are common.

Reproduction . Stein (1883) figured an individual
containing a resting cyst (pi. 7, fig. 2). He also showed
an emerging cyst (pi. 7, fig. 9) with the girdle indicated.
Other figures by Stein represent cysts with two and four
daughter cells (swarm spores?) with girdles (figs. 11,
12). Finally, Stein presented (figs. 13-16) specimens
which he interpreted as representing stages intermedi-
ate between these young daughters and the mature spec-
imens. His material was from the Baltic and Atlantic.
Schutt (1895, pi. 8, fig. 30, 9, 10) shows daughter cells
with half-old and half-new thecae, also a "double spore"
(fig. 30, 7). No specimens representing reproductive
stages were found in the Carnegie material.

Distribution . Paulsen (1908) stated that Gonlodoma
polyedricum is an Atlantic subtropical species. Lebour
(1925) also designated it as subtropical. Both authors
record the species as rare in the Gulf Stream. It is,
however, a widespread tropical species, as shown by
the Carnegie and other observations. It was reported
from the tropical Atlantic by Schmidt (1901) and Pavil-
lard (1931); from the Baltic by Aurivillins (1896) and
Abshagen (1909); from the Mediterranean by Schmidt
(1901), Forti (1922), Issel (1928), and Paulsen (1931);
from the Pacific by Schmidt (1901); and from the Indian
Ocean by Schmidt (1901), and Matzenauer (1933).

In the Carnegie collection G. polyedricum was found
at 148 stations: 30 in the Atlantic and 118 in the Pacific.
There are 471 records of occurrence: 280 rare, 178
occasional, and 13 common. The species was found less
frequently with Increase in depth, with 218 records for
the surface, 143 for 50 meters, and 110 for 100 meters.
There are 190 pump records and 281 net records. It
was found in both hemispheres and in all months of the
year.

The species was found at practically every station
In the tropical and subtropical regions, and it strayed
beyond these regions much more than did most of the
other tropical forms (fig. 61). Thus, it was foimd in the
North Atlantic Drift as far as the British Isles (station
6c); in the western Pacific north of 40° north; in the
eastern Pacific to 37° north; and in the South Pacific to
40° south. There was no particular center of abundance.
The records of "common" and "occasional" were scat-
tered throughout the range.

The surface temperatures at the stations where the
species occurred at any depth varied from 12"4 to
29.°5 C. The ranges of hydrographic conditions in situ
were as follows: temperature, 10° 6 to 29°. 6 C; salinity,
29.7 to 37.1 o/oo;, pH, 7.17 to 8.47; phosphate, 3 to
198 mg P04/m3.

It can be concluded from Carnegie observations that
Gonlodoma p olyedricum is a fairly common, widespread,
tropical species. It is similar to Ceratocorys horrida
In this respect, but it extends into water of lower tem-
perature. Thus, it was found near the British Isles

where the surface temperature was only 12 °4 C; north-
east of Japan where the surface temperature was 15 °9;
off California, in 16 °2 water; and in the southeastern
Pacific, in 15° water. It occurred at 6 stations where
the surface temperature was less than 19°. This species
should be an excellent plankton indicator, as it is ubiq-
uitous in the tropics and seems to survive transfer to
cooler regions. It should indicate water masses of
tropical origin.

The species apparently suffers no decrease in wa-
ters of low nutrient content. There were 165 records in
water with less than 10 mg P04/m3.

Family GONYAULACACEAE Lindemann

Diagnosis . "Shape very variable, spherical, angu-
lar, elongate, sometimes with hornlike processes or
distinct spines at both ends. Girdle about equatorial,
often strongly spiraled. Small posterior intercalary
present. Length, 18 microns to 167 microns." (Linde-
mann, p. 84, 1928.)

Genus GONYAULAX Diesing

Diagnosis . "Body variously shaped, spheroidal,
polyhedral, broadly fusiform, elongated with stout apical
and antapical prolongations, or dorso-ventrally flat-
tened. Apex rounded or truncate symmetrically or a-
symmetrically, never acutely symmetrically pointed.
Antapex rounded, flattened, or pointed symmetrically or
asymmetrically. Girdle usually equatorial, descending,
displaced dlstally one to seven times its own width, and
sometimes with slight overhang. Transverse furrow
impressed or not; longitudinal furrow usually slightly
indenting the epitheca, often flaring dlstally, well devel-
oped, reaching to or approaching the antapex. Thecal
wall consisting of one to six apical plates, none to three
anterior intercalaries, six precingulars, six girdle
plates, six postcing^ulars, one posterior intercalary, and
one antapical. The longitudinal furrow occupies the
whole of the ventral area which slightly indents the epi-
theca and consists of one anterior, about four interme-
diate and one posterior plate. The midventral plate of
the apical series is usually a narrow plate extending
posteriorly to a junction with the anterior plate of the
ventral area, thus parting precingulars one and six.
When guarded by lateral ridges it simulates an anterior
extension of the longitudinal furrow. It bears at its apex
a delicate extension, the closing platelet wJiich covers
the apical region.

"Surface smooth or rugose with major thickenings
along suture lines and minor ones on plates forming a
regiilar or irregular polygonal mesh of varying size,
often with vermiculate, longitudinal elements predomi-
nating, sometimes spinulate. Furrows with or without
lists which in many species are ribbed or spinulate. One
or more antapical spines sometimes present, rarely
with sheathed spines of the Ceratocorys type. Plates
porulate, with pores in centers, angles, or nodes of the
mesh. A peculiar large ventral pore occurs to the right
of the midventral line usually near the suture between
apical one and the plate to its right. Theca divided ob-
liquely in fission. Ecdysis frequently seen. Chromato-
phores yellow to dark brown, often dense. In fresh,
brackish, and marine waters from boreal to tropical

48

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

regions." (Kofoid, 1911a, p. 196.)

Remarks . The present diagnosis of the genus will
undoubtedly be radically revised upon a more intensive
study of the morphology of the species now included in
the genus. Judging from the results of the careful dis-
section of the two species included in this report, it can
be concluded that many of the specific diagnoses are
probably in error. In addition to this, it is likely that
the genus as now conceived Includes several groups of
generic status.

In his first diagnosis of this genus, Kofoid {1907b)
gave the plate formula as 6ap, 6pr, 6po, lant, 1 longi-
tudinal ventral furrow plate, 1 girdle plate. Apparently
this analysis was made without dissection of the plates,
and the many ridges and markings of the theca led to an
erroneous conclusion as to the plate pattern. Later,
Kofoid (1911a) stated that his first interpretation was in
error and gave a new diagnosis which agrees much
more closely with that found in the two species present-
ed here. His new formula is "Sap, Oa, 6pr, 6g, 6po, Ip,
lant, ventral area consisting of a narrow anterior plate,
large posterior plate, and at least three intermediate
plates." In the present investigations complete dissec-
tions were made of the entire skeleton of G. pacifica and
G. fuslformis . The plate formula of these two species
is as follows: Sap, 2a, 6pr, 6g, 6-7s, 6po, Ip, lant.

Whedon and Kofoid (19S6) made an analysis of two
new species, G. catenella and G. acatenella . The for-
mula for each of these is the same, viz., 4ap, Oa, 6pr,
6g, 5s, 6po, Ip, lant. This formula is sufficiently dif-
ferent from that of G. pacifica and G. fusiformis to jus-
tify generic separation. Gonyaulax pacifica and G. fusi -
formis have one less apical, two (instead of no) anterior
intercalaries, and two more sulcal plates. The facies
of the ventral part of the epitheca as well as the size
and shape of the body generally of Whedon and Kofoid' s
two species is quite different from those of G. pacifica
and G. fusiformis .

The present work on the genus Gonyaulax shows
clearly that a complete reclassification of this and re-
lated genera is quite necessary. A re- examination of
the whole group on the basis of thorough morphological
studies is absolutely essential. Quite new conceptions
of relationships within the group will undoubtedly result
from such a critical analysis of extensive material. As
an example of a realigning, resulting from such thor-
ough studies, it may be mentioned that G. ceratocoroides
Kofoid has been placed in a separate genus.

Gonyaulax pacifica Kofoid
(Figure 62)

Gonyaulax pacifica Kofoid, 1907b, p. 308, pi. SO, figs. 37-
39. Kofoid, 1911b, p. 235, pi. 15, fig. 35. Pavillard,
1931, p. 51.

Steinlella cornuta Karsten, 1907, pp. 348, 420, pi. 53,
HgT?.

Dimensions . Length of body, exclusive of antaplcal
spine (I), 155 (131-263) microns. Transdiameter (d'),
80 (52-105) microns. This diameter Is the greatest di-
ameter, not the diameter seen in true ventral view (see
below). Width of girdle, about 5 microns. Twenty-two
specimens were measured.

Shape . Body about twice as long as greatest diam-
eter. Thei/d' ratio is 1.98 (1.66-2.65). Body extreme-
ly asymmetrical, probably as a result of a differential

growth in which the left side has grown decidedly larger
than the right. The short diameter (d) is about 0.6
times the long diameter (d') (see fig. 62D). Epitheca
compressed dorsoventrally, very abruptly from the gir-
dle so that the distal half of the epitheca extends as a
bladelike horn (fig. 62A, C, I, J). Hypotheca also very
strongly compressed dorsoventrally, but here the com-
pression is accompanied by a strong dorsal curvature
of the body which results in a concavity on the ventral
face and in an extreme approximation of the dorsal and
ventral'waUs of the hypotheca, especially on the right
side. Thus, the more posterior part of the hypotheca is
concave blade-shaped and the entire hypotheca is "scoop-
like" as Kofoid (1911a) described it. Posterior edge of
body rounded in ventral view with extension on left side
terminated by a spine which is from 1 to 2 girdle
widths long. The asymmetrical shape of the body re-
sults in quite different contours when the body is viewed
from slightly different angles. Figure 62A shows a
specimen presenting its widest ventrolateral aspect, and
figure 62H, a strictly ventral view, presents a narrower
body diameter but shows the broadest view of the ven-
tral area.

Girdle slightly behind the middle; sinistral; ends
curved ventrally, particularly the proximal end; dis-
placed 1.5 to 3.0 girdle widths, no overhang; greatly ex-
cavated, often as much as 1 girdle width (fig. 62B).

In connection with the unequal development of the two
sides of the body, there has been a rotation of the long
axis of the sulcus and ventral area so that in ventrolat-
eral view only the right side of the ventral area is visi-
ble. Ventral area more or less elliptical in outline,
somewhat sigmoid in ventral view but not in the flat ven-
trolateral view. Anteriorly the area extends into the
epitheca about 3 girdle widths. Greatest width of area
attained about halfway to antapex. Posteriorly the area
tapers to a point about 2 girdle widths from base of ant-
apical spine. Sulcus a deep groove on left side of ven-
tral area. Flagellar pore narrow and long (about 3 gir-
dle widths), sigmoid in outline, following the curvature
of the ventral area (fig. 62K), and extending posteriorly
from proximal end of girdle.

Plate pattern . The three apical plates very imequal
in size. First apical very narrow with narrow extension
to girdle (fig. 62C). Apical closing platelet present,
sometimes loosely attached to anterior end of first api-
cal plate. Kofoid (1911a) stated that the platelet is a
definite part of the first apical, but the writer has found
that it may be detached quite easily. Second apical plate
is large and composes almost all of distal end of apical
horn. It has a Umb projecting arotmd the apex to right
side and fitting into a shoulder of first anterior interca-
lary (fig. 62D, I). Third apical a long triangiilar plate
with its apex at apex of specimen and its base along mar-
gin of second anterior intercalary (fig. 62C, D). This
apical was shown in Kofoid's (1907b) earlier drawing,
but he later (1911a) rescinded his earlier diagnosis of
this species and omitted this plate.

First anterior intercalary, a large plate running
almost to apex, where it has a shoulder into which fits
the projection of a2. This plate was included in apS by
Kofoid (1911a), who apparently had not separated it from
that plate. The second anterior intercalary hasnotbeen
reported before for this species, but was easily deter-
mined in all specimens examined. It is probably homol-
ogous with al in Splraulax kofoidii . It frequently bears
a double ridge running transversely across its middle

FAMILY GONYAULACACEAE

49

(fig. 62A).

The six precingulars of rather unequal length.

The six girdle plates subequal in size except for g6,
which extends from distal end of girdle well around to
dorsal side of body (fig. 62F); all U-shaped in cross
section (fig. 62B).

First postcingular small; anterior to pol; forms
left edge of flagellar pore (fig. 62C, L). It is similar in
size and position to pol in Ceratocorys . Second to
fourth postcingulars larger; subequal in size; occupy
left ventral and left lateral regions of hypotheca (fig.
62G). Fifth and sixth postcingulars large; the fifth is
dorsal, the sixth lateral and ventral. The sixth is ex-
tremely compressed and forms the lateral keel of hypo-
theca.

Posterior intercalary plate, a long narrow plate ex-
tending from pol along left edge of sulcus to antapical
plate (fig. 62A, C, H, G, L). It bears the wide left sulcal
list.

The antapical plate constitutes the compressed ant-
apex. A corner of it extends almost halfway to girdle on
left side of body (fig. 62J). Other margins of this plate
more limited, especially ventrally, where a narrow
strip only 1 girdle width wide is visible (fig. 62C). This
plate bears the antapical spine at its left ventral corner.

Ventral area composed of seven plates (fig. 62K, L);
anterior, posterior, right, left, right accessory, poste-
rior accessory, and intercalary. The anterior sulcal
plate consists of two inseparable parts. Posterior part
roundish, with semicircular notch posteriorly which rep-
resents anterior edge of flagellar pore. Anterior part
is a process extending into epitheca between base of
first apical and sides of a2 and pr6 (fig. 62C). Posteri-
or sulcal plate large, subtriangular, with oblique base
anteriorly where it borders left and intercalary sulcal
plates. Remaining five sulcal plates lie between the
anterior and the posterior; three on the right side, one
on the left side, and one in the middle. Those on the
right side, reading posteriad, are the right accessory,
right, and intercalary. Of these, the right accessory
and part of the right constitute the right edge of flagel-
lar pore. Posterior edge of pore formed by tip of pos-
terior accessory, which lies between rs, i, and Is, but
does not touch ps. Part of left edge of the pore formed
by extension of Is; the rest by pol. Thus, all sulcal
plates touch the pore except the intercalary and posteri-
or.

Body wall . Many prominent narrow lists rim longi-
tudinally along body; some run whole length of epitheca,
others extend onlv a short distance from girdle. Most
of these "ridges' bear no relation to sutures although
they have been so confused in the past. Sutures are often
mariced by low, narrow ridges; sometimes one on each
side of intercalary zones. Second anterior intercalary
frequently has a double line, indicating some sort of
zone, running transversely through its middle.

A ventral epithecal pore occurs on left anterior cor-
ner of second anterior intercalary plate. Apical pore
covered by closing platelet. Minute tubercles are scat-
tered over major plates rather irregularly, although
they have a tendency to be arranged in rows. Kofoid
(1911a) interpreted these as pores. Some of the sulcal
plates may have similar tubercles or, sometimes, faint
reticulations (fig. 62A). Girdle plates crossed trans-
versely by a varying number of ridges, usually spaced
about 0.5 girdle width apart.

Lists . Although there are an excessive number of

body lists in this species, the usual list systems are
rather poorly developed. Girdle lists small or absent,
never over 0.5 girdle width wide. Ribs and other struc-
tural differentiations are absent on these lists. The
only wide list of the species is the left sulcal list, which
in the broad ventrolateral aspect of body covers half of
ventral area posterior to distal end of girdle (fig. 62 A).
It is attached to right and anterior edges of posterior
intercalary plate (fig. 62L). Right sulcal list absent on
hypothecal part of ventral area, but the anterior right
sulcal list is well developed. It occurs on right edge of
epithecal extension of ventral area and is attached to
pr6. In apical view it is visible as a "spine" at distal
end of girdle (ar, fig. 62D). The body list along right
keel of hypotheca is well developed and may attain a
width greater than 1 girdle width.

Antapical spine often curved to the right. Its length
varies considerably, viz., from 0.8 to 2.2 girdle widths.
It may bear small lists or large reticulations.

Variation . In thin-walled specimens the second
anterior intercalary usually is quite hyaline and struc-
tureless. This may be the reason why this plate has
previously gone unnoticed, for in such cases it may eas-
ily be mistaken for a wide intercalary zone if careful
dissections are not made.

There is considerable variation in shape of body;
for instance, the degree of compression in the girdle
region may be low (see fig. 62E), and the antapex may
be extended as a slight horn (fig. 62H).

Distribution . Gonyaulax pacifica is a rare, seldom
reported species, although it has a wide distribution
over the tropical seas. Pavillard (1931) reported it
from the Atlantic and from the Mediterranean (1909,
1931). Previous to the Carnegie cruise it had beenfound
in the Pacific only at San Diego (Kofoid, 1907b) and in
the Indian Ocean only by Karsten (1907). Bohm (1936)
states it had never been foimd in the western Pacific,
and Matzenauer (1933) did not find it in the Indian Ocean.

In contrast with this apparent rarity, the species
was found at 77 Carnegie stations: 15 in the Atlantic and
62 in the Pacific. There are 163 records of occurrence:
140 rare and 23 occasional. It was never common or
abundant. It was found less at the surface than at the
lower levels, with 19 records for the surface, 73 for 50
meters, and 71 for 100 meters. There are 107 net rec-
ords and 56 pump records. It was found in both hemi-
spheres and in practically all months of the year.

Gonyaulax p acifica was found rather consistently
throughout the tropics, although there are many gaps in
its distribution (fig. 61). In the Atlantic it was found at
all stations south of station 15, although not at.station
24 or in the Caribbean. Although the records are not
continuous south of 40° north, it was not found north of
that latitude.

In the Pacific the records are even less complete
than in the Atlantic. There is no significant geographic
grouping of the record stations, however, and it is prob-
able that the species is more uniformly distributed than
the present records indicate. It is equally common in
the western Pacific and in the eastern Pacific. It was
not found north of latitude 35° north nor south of 32°
south.

Although the Carnegie records do not show a con-
tinuous distribution in the tropics, the limits of the dis-
tribution of the species show a close correlation with the
surface isotherm of 20° C (fig. 61). At the stations
where the species was found, the surface temperatures

50

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

were above 20° C, except at station 66, where the tem-
perature was 19°.4 C.

On the basis of these data, G. pacifica must be con-
sidered a strictly tropical species which does not endure
transfer to colder regions. For this reason it is a good
indicator of tropical water masses, although not so good
as Ceratocorys horrida because of its less frequent oc-
currence.

Water of low nutrient content is no barrier to the
species, as there are 89 records of its occurrence in
water with less than 10 mg VO^/vcfi.

The surface temperatures at the stations where the
species occurred at any depth varied from 19°4 to
29 °4 C. The ranges of hydrographic conditions in situ
were as follows: temperature, 1°.4 to 29°.3 C; salinity,
33.4 to 37.1 o/oo; pH, 7.17 to 8.39; phosphate, 3 to 121
mg P04/m^.

Gonyaulax fusiformis n.sp.
(Figure 63)

Dimensions . Length of the body (1^), excluding ant-
apical spine, 86 (67-98) microns. Diameter (d), 47 (35-
57) microns. Width of girdle, 4.8 (4-5.5) microns.
Length of antapical spine, 17 (12-23) microns. Seven
specimens were measured.

Shape . Body broadly fusiform. The j/d ratio is
1.82 (1.68-1.98); thus body may be almost twice as long
as wide. Epitheca extended into a long apical horn equal
in length to rest of epitheca. Apex somewhat less than
1 girdle width in diameter. On left side, body tapers
gradually from girdle to apex, but on right side there is
a prominent shoulder as in Spiraulax. Hypotheca tapers
uniformly to antapex except for a constriction about 3
girdle widths from base of antapical spine (fig. 63D, E,
G). Body circular in girdle section (fig. 63B, F). Gir-
dle approximately equatorial, sinistral, displaced from
1.5 to 2.5 girdle widths, slightly concave; usually with
no overhang. Ventral area very narrow, usually almost
straight posteriorly, but bends to left anteriorly; some-
times slightly sigmoid. Posteriorly it flares out into an
elliptical area, similar to, but not so wide as, that in
Spiraulax . Anterior sulcal plate has an extension into
epitheca (as, fig. 63B). Flagellar pore a long, narrow
slit situated at left edge of ventral area between dis-
placed girdle ends and continued posteriorly about 1
girdle width.

Plate pattern . The three apical plates quite unequal
in size. First apical is long, narrow, and curved, and
extends f(om apex to anterior sulcal plate on ventral
side of epitheca (fig. 63E). Second apical extends from
first apical around to dorsal side of body (fig. 63B); at
apex it has a limb (x, fig. 63B). about 1 girdle width
wide which fits Into a shoulder formed by the withdrawal
from the apex of the first anterior intercalary plate.
This process meets a similar process from the third
apical (y, fig. 63B, G). Body of third apical linear, ex-
tending along right side of distal half of first apical.
Therefore it lies between the first and second apicals
and between the apex and the two anterior intercalary
plates. The two anterior intercalaries make up the
greater part of right side of apical horn. The second of
them is on ventral face of body touching six different
plates, including first and third apicals, sixth precingu-
lar, and anterior sulcal plates. The six precingulars
are of approximately equal width except the first, which

is somewhat wider.

The six girdle plates approximately equal in length,
with sutures as shown by arrows in figure 63A.

The six postcingular plates are about equal in width
except the first, which is small and narrow and lies
along left edge of flagellar pore (fig. 63E, F). A single
antapical plate extends almost halfway up the right side
of sulcus. It bears the heavy antapical spine and the
"sulcal spine" (fig. 63F, G). The posterior intercalary
forms the left edge of ventral area posterior to first
postcingular.

Ventral area composed of six plates: anterior, pos-
terior, left, right, right accessory, and intermediate
(fig. 63C). Posterior accessory absent. Sulcal plate
has a projection into epitheca which meets the first api-
cal plate. A notch in posterior end of this plate repre-
sents anterior edge of flagellar pore as in G. p acifica .
Posterior sulcal plate comprises the expanded elliptical
posterior part of ventral area. It extends to within 1
girdle width of distal end of girdle. Left sulcal plate
forms posterior edge of flagellar pore and has a process
extending anteriorly along left edge of pore to meet first
postcingular plate, which also borders pore. Right and
right accessory plates form right edge of flagellar pore;
the right is opposite distal end of girdle; the right ac-
cessory is anterior to this. Intercalary sulcal plate is
small, square, posterior to right plate, and removed
from flagellar pore.

Thus the flagellar pore is boimded by the first post-
cingular and four sulcal plates: the anterior, left, right,
and posterior accessory. The intercalary and posterior
sulcal plates do not touch the pore.

Thecal wall . All plates of body except some of sul-
cal plates covered with a fine areolation which extends
completely to edges of plates. Most plates also bear a
few large, irregularly scattered pores, which, in optical
section, can be seen to pierce the body wall. They oc-
cur on the anterior, posterior, and left sulcal plates, but
frequently occur only In rows along the edges or ridges
of the narrower plates. One row occurs along each edge
of girdle plates.

Intercalary zones occur along most of sutures and
are marked by a fine areolation and absence of pores.
Body ridges usually some distance from sutures, and the
intervening space may be considered the intercalary
zone, as it is probable that the ridge represents the o-
riginal suture line.

The ventral epithecal pore so characteristic of Gon -
y aulax is present here at left anterior corner of second
anterior intercalary plate. Apical pore closed by a very
hyaline apical closing platelet.

Lists. Girdle lists about 0.75 girdle width wide,
usually strengthened by simple ribs extending from body
to the edge of the list, spaced from 0.5 to 1 girdle width
apart (fig. 63A). Girdle plates free of ridges. Right and
left sulcal lists present. Posterior part of right sulcal
list attached to po6 and antl. A prominent, characteris-
tic spine, the sulcal spine, occurs in the middle of this
list at anterior corner of antapical plate. Anteriorly,
this list is continuous with posterior girdle list. Poste-
riorly it terminates at posterior end of ventral area.
The anterior (epithecal) part of right sulcal list is at-
tached to pr6 and as and is continuous posteriorly with
distal end of anterior girdle Ust.

Although the boundaries of most of plates are Indi-
cated by ridges placed at some distance from the edges,
certain sutures are not so marked and extra ridges oc-

FAMILY GONYAULACACEAE

51

cur on many plates. Thus any diagnosis of the plate pat-
tern based on the pattern of ridges would be erroneous.
Careful dissection is necessary to insure a correct plate
formula. The third apical and the second anterior inter-
calary are particularly difficult to demonstrate. The
second apical bears two ridges removed from the edges;
the first anterior intercalary has three (fig. 63 A).

The antapical spine is massive, solid, and conical,
terminating the hypotheca and borne by the antapical
plate. It Is 4.1 (2.4-4.5) girdle widths long and from 1
to 2 girdle widths in diameter at base. It is covered
with the same fine areolation as that of the body and is
marked with ridges running longitudinally.

Variation . Gonyaulax fusiformis shows considera-
ble variation in size and in length of antapical spine, but
other characters are comparatively constant. Length of
body varies from 67 to 98 microns; length of antapical
spine from 12 to 23 microns or from 2.4 to 4.5 girdle
widths. Body shape very constant except that width at
girdle shows a tendency to vary; the_l/d ratio varies
from 1.68 to 1.98. Sometimes the "sulcal spine" is
double, and one specimen was found without this spine.
The surface markings show a high degree of constancy,
being always a very delicate areolation with scattered
large pores. The right sulcal list may end at sulcal
spine or may continue beyond to antapical end of sulcus.

Comparisons . Although the plate pattern of G. fusi -
formis is ftmdamentally similar to that of G. pacifica , it
differs somewhat from that of the latter species. Its ma-
jor plate pattern is composed of the same number of
plates as that in G. p acifica, but the arrangement of its
plates differs from that in G. p acifica in some respects.
Its first apical does not reach the girdle as it does in G.
pacifica , but extends only to the anterior sulcal plate.
Its third apical is much smaller, so that its second an-
terior intercalary touches the first intercalary, which is
not the case in G. p acifica . The apical process of ap31s
not represented in G. p acifica .

In regard to the ventral area, the arrangement of the
plates in G. fusiformis is rather similar to that in G.
pacifica , but there is one less plate in the former spe-
cies; the posterior accessory is lacking. In G. pacifica
the Intercalary plate is next to the largest of the sulcal
complex, whereas in G. fusiformis it is the smallest.
Its position, however, on the right of the sulcus just an-
terior to the posterior plate and not touching the flagel-
lar pore, is the same in the two forms. The extra sul-
cal plate in G. p acifica, the posterior accessory, is pos-
terior to the flagellar pore. Its anterior end forms the
posterior end of the pore. It has probably been formed
by the splitting off from its neighbor to the left, the left
sulcal plate. Thus, tlie left and posterior accessory sul-
cal plates in G. pacifica would be homologous with the
left sulcal plate in G. fusiformis ; this latter plate has an
arm extending along the left side of the pore to pol,
probably homologous with the anterior part of the left
sulcal plate in G. p acifica .

Gonyaulax fusiforiais shows some relationship to
Spiraulax kofoldli and in some respects it is intermedi-
ate between Spiraulax and Gonyaulax . It agrees with
Spiraulax in that the second anterior intercalary plate
touches the first (which in Spiraulax. however, is the
third apical). It also agrees in the number of the sulcal
plates, viz., six. The general arrangement of the sulcal
plates in the two species is the same although there are
two important differences in the details of the arrange-
ment: First, in Spiraulax the left sulcal plate does not

have an arm extending along the side of the flagellar
pore, so that the entire left side of the pore is formed
by the first postcingular plate; the left sulcal plate marks
only the posterior edge of the pore. Secondly, the rela-
tive sizes of the plates differ in such a way that in Spir -
aulax the right sulcal plate has been squeezed out from
contact with the pore, so that the right side of the pore
is formed chiefly by the right accessory sulcal plate and
to a small extent by the notch of the anterior plate. So
far as the sulcus is concerned, it may be concluded that
G. fusiformis is more closely related to G. p acifica than
to Spiraulax . The agreement with Spiraulax in the num-
ber of plates is outweighed by the difference in the pat-
tern of the sulcal plates. Only the splitting of one plate
in G. pacifica is sufficient to show good agreement with
the sulcal plates of G. fusiformis, whereas considerable
adjustment of plates surrounding the pore would be nec-
essary to show agreement with Spiraulax .

Differences in the epithecal plate pattern emphasize
the distant relationship of these two forms. In Spiraulax
the plate which is homologous with the first anterior in-
tercalary in Gonyaulax fusiformis is an apical. Thus in
Spiraulax there are four aplcals and only one anterior
intercalary, whereas in G. fusitormis there are only
three aplcals and two intercalaries. In Spiraulax the
first apical does not extend either to the girdle or to the
anterior sulcal plate, but terminates at the anterior
margin of the first precingular, so that the anterior In-
tercalary extends over and touches the first precingular.
Kofoid (1911b) stressed this point in creating the genus
Spiraulax . The ventral epithecal pore so characteristic
of the genus Gonyaulax is absent in Spiraulax .

There is a superficial resemblance between G. fusi -
formis and Spiraulax in general body shape, so that
when a specimen of the former species is viewed under
the low power of the microscope it may be confused with
a species of Spiraulax . Under the high power, however,
a glance at the surface of the plates is sufficient to dis-
tinguish these two forms without any analysis of the plate
pattern. Spiraulax is coarsely reticulate or with round-
ed pits, without apparent pores. Gonyaulax fusiformis
is very finely areolate with a few large pores scattered
over the plates. The prominent sulcal spine will dis-
tinguish this species from Spiraulax. although its ab-
sence is not a positive identification of Spiraulax .

Blstorical . It Is possible that Murray andWhitting's
Gonyaulax j oUlffel (1899, p. 324, pi. 28, fig. la, b) was
based on an aberrant specimen of G. fusiformis (see p.
54). The plate pattern is so poorly figured by these
authors that definite identification is not possible. The
presence of a left sulcal spine and the general body
shape suggest, however, that Murray and Whittlng s form
is not specifically identical with our material. For this
reason and in order to avoid confusion in the literature,
it was deemed advisable to give our species a new name
and to retain the name Gonyaulax j olllffel for Murray
and Whltting's species. Kofoid s Spiraulax is separate
from each of these (see p. 52).

Gonyaulax fusiformis was figured by Pavillard(lQSl,
pi. 2, fig. 3) under the caption Gonyaulax birostrls Stein.
Although the plate pattern is not indicated, this form Is
easily Identifiable with the present species by its char-
acteristic body shape and antapical spine. The spedas
differs from G. birostrls Stein in body shape and pUto
pattern.

Distribution . Pavillard (1931) reported this spe-
cies from the tropical Atlantic.

52

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

In the Carnegie collection G. fusiformis was found
at 19 stations: 2 in the Atlantic and 17 in the Pacific.
There are 33 records of occurrence, all rare. The spe-
cies occurred about equally at the three depths, with 12
records for the surface, 12 for 50 meters, and 9 for 100
meters. There are 21 pump records and 12 net records.

The species was closely limited to the tropics. In
the Atlantic it did not occur north of 30° north. In the
Pacific it was not found north of 29° north or south of
16° south. No center of abundance was indicated. The
17 record stations in the Pacific were rather irregular-
ly scattered and showed no correlation with geographic
location or with dynamic conditions (fig. 61).

The sxirface temperatures at the stations where the
species occurred at any depth varied from 22° 7 to
28°.7 C. The hydrographic conditions in situ were as
follows: temperature, 18°.7 to 28°.7 C; salinity, 34.2
to 37.0 o/oo; pH, 8.16 to 8.39; phosphate, 3 to 40 mg
P04/m3.

This is obviously a rare tropical species restricted
to warm water. It is remarkable that it was found more
often in the nutrient-poor water. Of the 33 records of
occurrence, all but 7 were in water with a phosphate
content less than 10 mg P04/m3. Type locality: Car -
negie station 18.

Genus ACANTHOGONYAULAX (Kofoid) Graham

Diagnosis . Body angular, with prominent lists and
brush-formed hypothecal spines simulating Ceratocorys .
Girdle premedian. Plate pattern: apical platelet, 3ap,
9pr, 6g, 7s, 6po, Ip, lant. Ventral epithecal pore on
first apical plate. One species. Marine.

Type species . Acanthogonyaulax spinifera (Murray
and Whitting) Graham.

Historical . Acanthogonyaulax was proposed as a
subgenus of Gonyatilax by Kofoid (1910) to include Mur-
ray and Whitting s (1899) Ceratocorys spinifera (see
below, pp. 51-52). This subgenus is here raised to the
rank of genus.

Comparisons . Acanthogonyaulax has a superficial
resemblance to Ceratocorys, particularly to C. horrida .
The hypotheca of Acanthogonyaulax resembles that of C.
horrida in the great development of antapical brush
spines and in the intervening lists. The epitheca, on the
other hand, is prolonged into a short tubular horn,
whereas in Ceratocorys the epitheca is low dome-shaped.

A more fundamental resemblance between these two
genera is expressed by the similar number and pattern
of the major hypothecal plates. There is a disparity in
the size of some of these plates, however.

The posterior intercalary is much more extensive,
and the first postcingular is gomewhat larger in Acan -
thogonyaulax than in Ceratocorys . The second postcin-
g\ilar, on the other hand. Is a small ventral plate in
Ceratocorys . whereas In Acanthogonyaulax it is large,
equal in size to the postcingulars of the lateral and dor-
sal sides.

The epitheca of Acanthogonyaulax differs markedly
from that of Ceratocorys, not only In shape but also in
the number and the pattern of the plates. The number
of precingular plates in Ceratocorys Is five; in Acan -
thogonyaulax it is nine. The major part of the epitheca
In Ceratocorys is composed of four precingular plates,
whereas in Acanthogonyaulax six of the precingular
plates constitute most of the epitheca. The small first

precingular plate in Ceratocorys is represented in
Acanthogonyaulax by three minute precingulars. The
apical region in Ceratocorys is composed of four plates:
two apicals and two inter calaries; in Acanthogonyaulax
there are three plates in this region, all apicals.

A study of the sulcal complex of these two genera
shows even less relationship between them than does a
comparison of the epithecal plates. There are seven
plates in the ventral area of Acanthogonyaulax , and only
five in Ceratocorys . Acanthogonyaulax is unique in that
the anterior sulcal plate is removed from the flagellar
pore. In Ceratocorys the posterior part of the ventral
area never flares out into a prominent part of the ven-
tral aspect as it does in Acanthogonyaulax . This feature,
on the other hand, is characteristic of Gonyaulax .

Acanthogonyaulax is more closely related to Gon -
yaulax than to Ceratocorys . The hypotheca has the same
number of plates in the two genera, although the arrange-
ment is somewhat different. In Gonyaulax the first post-
cingular is much smaller and the posterior intercalary
is much longer and narrower than in Acanthogonyaulax .
The antapical plate in Gonyaulax is more restricted.

It is more difficult to compare the epithecal and
sulcal plates of Acanthogonyaulax with those of Gonyau -
lax than with those of Ceratocorys because so little crit-
ical work has been done on Gonyaxilax . For that reason
the present discussion is based on only two species of
Gonyaulax ; G. pacifica and G. fusiformis . As stated
above (p. 46), the present concept of the genus Gonyau -
lax is probably too broad.

The first apical plate in Acanthogonyaulax does not
extend to the girdle or to the ventral area; in Gonyaulax
it extends to the girdle. The number of precingular
plates is six in Gonyaulax, nine in Acanthogonyaulax .
The extra three precingulars in the latter genus are the
three minute ventral ones, the first, second, and third.
It is possible that the first two represent the anterior
part of the anterior sulcal plate of Gonyaulax," in which
case the anterior part not only has separated from the
posterior part but also has spUt longitudinally. The
third precingular could, then, represent the lower part
of the first antapical of Gonyaulax . There is much great-
er difficulty in homologizing the sulcal plates proper of
these two genera, in spite of the fact that the total nimi-
ber of plates may be the same. The flagellar pore does
not bear the same relation to the various plates in the
two genera (see fig. 1). In Acanthogonyaulax the anteri-
or sulcal plate is removed from the pore, whereas in
Gonyaulax it forms its anterior edge. In Acanthogonyau -
lax the pore is bordered by four plates, two anterior,
two posterior; in Gonyaulax it is bounded by five plates,
only one of which is anterior, one is posterior, the rest
lateral. The greatest resemblance in these areas seems
to be that the posterior plate in each case is the largest.
Their differente in shape, however. Is extreme. In
Gonyaulax it is subelliptical; in Acanthogonyaulax , sub-
triangular with two widespread limbs.

On the basis of the differences In the epithecal and
sulcal plate patterns, we are forced to conclude that
Ac anthogonyaulax Is only remotely related to the species
of Gonyaulax included in this report. If further investi-
gations show that other species, now allocated to Gon -
yaulax , are similar in pattern to G. pacifica and G. fusi -
formis , then we may conclude that Acanthogonyaulax
and Gonyaulax not only are distinct genera but are sep-
arated by a divergent evolutionary development of con-
siderable extent.

FAMILY GONYAULACACEAE

53

Acanthogonyaulax spinifera

(Murray and Whitting) Graham

(Figures 64, 65)

Ceratocorys spinife ra Murray and Whitting, 1899, p.

329, pi. 30, figTBa, b, e (not fig. 6c, d).
Gonyaulax ceratocoroides Kofoid, 1910, p. 182. Kofoid,

1911a, pp. 202, 247. Pavillard, 1931. p. 50, pi. 2,

fig- 2.

Dimensions . Length (h), measured in ventral view
from apex to posterior end of sulcus, 63 (55-75) mi-
crons. Diameter (d) 49.5 (42-58) microns. Length of
ventral spines 23 (5-31) microns, or about 5 girdle
widths for the average.' Girdle width 4-5 microns.
Thirteen specimens were measured.

Shape . Strongly resembles Ceratocorys in general
appearance because of angularity of body and prominent
brushlike spines on hypotheca (figs. 64B and 65). Body,
including apical horn, somewhat longer than broad. The
h/d ratio is 1.27 (1.19-1.44). Body nearly circular in
girdle region (fig. 64C, E) but hypotheca very angular
posteriorly (fig. 64B, C). Epitheca rather low but ex-
tended as a tubular horn along its distal quarter. Be-
sides the constriction formed by the base of this horn,
there is another constriction halfway to girdle, promi-
nent only on the right side. Thus, there are two shoul-
ders on epitheca which are most distinct on the right
side of body (fig. 64B). Hypotheca squarish in outline,
sometimes with a constriction in the middle, at least ol
one side, usually the right (fig. 64B); truncated posteri-
orly. Antapex squarish and sunken in center (fig. 64B,
C). A bulge occurs on hypotheca at base of each ven-
tral spine. Girdle sinistral, displaced about 3 girdle
widths, not excavated; no overhang.

Ventral area narrow anteriorly but flares out pos-
teriorly to full width of antapex into a bilobed area.
Sulcus a deep, narrow groove occupying entire anterior
half of ventral area and obscured by various lists asso-
ciated with it (figs. 64B, 65). Flagellar pore occurs op-
posite distal end of girdle; almost hidden by overhang
of postcingular and right sulcal plates.

Plate pattern . The three apical plates are of une-
qual size. The first is narrow and ventral, and extends
only about two-thirds of way to girdle. It bears the ven-
tral eplthecal pore. The second and third apicals, only
half as long as the first, are broad and compose most
of apical horn (fig. 64B, E). Apical closing platelet
present. Anterior intercalary plates absent. Of the
nine precingular plates, the first three are minute
plates, just anterior to ventral area. The other six are
subequal in size and comprise the larger part of epithe-
ca (fig. 64E). The six girdle plates subequal in size.
(Girdle sutures Indicated by arrows in fig. 64E.) First
postcingular is a small narrow plate overhanging sulcus
as in Gonyaulax (fig. 64A, B). The other five postcingu-
lars large and subequal in size (fig. 64C). The posteri-
or intercalary plate lies between left side of ventral
area, the second and third postcingiilars, and the antap-
Ical plate. The antapical plate Is large and squarish,
constituting the truncated antapex. Its four long sides
border the third to fifth postcingulars and the posterior
sulcal plate, but it also has two relatively short sides
bordering the posterior intercalary and the sixth post-
cingular plates (fig. 64C).

Ventral area composed of seven plates. The poste-
rior sulcal plate Is the only large one and forms a ma-
jor part of the ventral aspect of hypotheca (fig. 64A, D).

Other sulcal plates minute. The anterior sulcal plate is
opposite the proximal end of girdle. It has no anterior
projection into epitheca. Posterior to this plate and just
anterior to flagellar pore are the right accessory and
left accessory sulcal plates. Between flagellar pore anc
posterior sulcal plate are three plates: on the left side
of left sulcal plate; on the right side, the right sulcal
plate; adjacent to the pore and between the last plate and
the posterior sulcal plate there Is an intercalary sulcal
plate (fig. 64A, D). Right sulcal plate overhangs pore in
such a way that it is ventral to left sulcal plate (fig. 65).

Thecal wall . Surface of larger body plates covered
with deep pits regularly spaced. Pores not demonstrat-
ed in these pits. Second and third precingular plates,
but not the first, with pores. Girdle plates with two
rows of pores. Ventral eplthecal pore occurs on right
edge of first apical plate.

Lists and spines . Lists and spines reach a high de-
velopment in this species. Girdle lists are usually a-
bout 3 girdle widths wide, strengthened by heavy ribs
which are connected to numerous heavy listlike cross
ribs on girdle plates (figs. 64C, E, 65). Strong lists bor-
der all margins of ventral area. Right sulcal list at-
tached to sixth postcingular plate. Left sulcal list at-
tached to first postcingular and posterior Intercalary.
These two lists extend onto ventral antapical spines.
Anterior (eplthecal) right sulcal list attached to ninth
precingular plate. It borders right margin of eplthecal
part of ventral area between girdle ends and extends
somewhat beyond, anteriorly. Body lists well developed
along all sutures of hypotheca and along all sutures of
larger precingular plates. Apical plates, however, sin-
gularly free of lists (figs. 64B, E, 65). All body lists
extending to girdle run out to edge of girdle lists. The
body lists often strengthened by irregularly scattered
ribs, usually extending out from base of Ust.

Long spines with "brushes" are a prominent fea-
ture of this species. These spines are formed at cer-
tain junctions of body lists. The two most prominent
spines are at the ventral corners of antapical plate; two
other antapical spines occur at the dorsal corners of
this plate. The fifth spine is left lateral in position, be-
ing located at left corner of the posterior Intercalary.
The "brushes" consist of secondary thickenings running
out from the primary thickening which composes the
body of this spine at the list junction.

Variation . Size and shape of body fairly constant.
The greatest variation occurs in the lists and spines.
The variations may represent growth stages. Length of
ventral spines, however, constant: from 20 to 31 mi-
crons except for one specimen with spines 5 microns
long. Displacement of girdle varies more than in most
species of Peridiniales; a continuous series with dis-
placements from 1.5 to 4 girdle widths was found.

All our specimens had five spines, although In one
case one spine was double. Murray and Whitting (1899)
stated that the usual number of spines Is six and that
they found one specimen with only two. Whether the
former value should be accepted may be considered
doubtful. Since the spines are developed at the junction
of lists, however, a maximum number of seven seems
possible. The spines may be straight or curved. Cur-
vatures are particularly evident in Murray and Whit-
ting's figures. Outer margins of lists may be straight
or very much indented in parts between spines or be-
tween spines and girdle list.

Historical . Murray and WhItUng (1899) described

54

STUDIES IN THE MORPHOLOGY, TAXONOMY, ANT) ECOLOGY OF THE PERIDINIALES

and tigured this species under the name Ceratocorys
spinifera . They not only erred in the generic allocation,
however, but they also confused the species with two
other species of Ceratocorys (Kofoid, 1910). Kofoid
(1910) realized the affinity of this species to the genus
Gonyaulax and placed it in this genus in his revision of
the genus Ceratocorys . No figures were given in this
report. Later, Kofoid (1911a) emphasized the differ-
ences between this and the other species of Gonyaulax
by placing it in a new subgenus, Acanthogonyaulax .
Since the specific name spinifera was preoccupied in
Gonyaulax , Kofoid proposed the new name ceratocoroides .
Kofoid (1911a, p. 202) described Acanthogonyaulax as
having six plates in the apical region instead of three.
He probably based his judgment on the drawings of
Murray and Whitting, in which the plate pattern of this
region is very obscure.

On the basis of a detailed study of the skeletal anat-
omy of this species and of all the species of Ceratocorys ,
as well as of two representatives of the genus Gonyau -
lax, Acanthogonyaulax is here raised to the rank of an
independent genus, related Iwth to Ceratocorys and to
Gonyaulax but separated from these genera by wide ev-
olutionary gaps. Since Murray and Whitting's specific
name spinifera is not preoccupied in Acanthogonyaula x,
it has priority and must be reinstated.

Distribution . Acanthogonyaulax spinifera is an ex-
tremely rare tropical species. Murray and Whitting's
(1899) original material was from the Atlantic. Pavil-
lard (1931) found this species at one station off Spain in
1905. Apparently these are the only records of its oc-
currence up' to the present investigations.

In the Carnegie collections the species was not
found in the Atlantic, but was collected at 22 stations in
the Pacific. These stations are widely distributed over
the tropical Pacific, grouped in the following manner:
in the North Pacific, 5 stations northeast of the Hawai-
ian Islands, 7 stations in the North Equatorial Current
north of the Marshall Islands, and 3 stations between
Guam and Tokyo; in the South Pacific, 2 stations east of
the Samoan Islands, and 5 stations between the Galapa-
gos and Easter Islands (fig. 61). There are 32 records
of occurrence: 30 rare and 2 occasional. The species
was found about equally at the 3 levels, with 10 records
for the surface, 12 for 50 meters, and 10 for 100 me-
ters. There are 24 net records and 8 pump records.

This tropical species reached its greatest distance
from the equator in the western Pacific, where it oc-
curred almost to 35° north (station 113). In the eastern
Pacific it was found only to 33° north (station 145). In
the South Pacific it was not found south of 19° south.
The 2 records of "occasional" were in the North Equa-
torial Current (stations 100 and 101).

The surface temperatures at the stations where the
species occurred at any depth varied from 22°.4 to
28°5 C. The ranges of hydrographic conditions in situ
were as follows: temperature, 16°0 to 28°6 C; salinity,
34.1 to 36.3 o/oo; pH, 8.16 to 8.39; phosphate, 3 to 40
mg P04/m^.

It may be concluded from the Carnegie observations
that A. spinifera is a very rare but widely distributed
tropical species, seldom collected because of its sparse
numbers. Water of low nutrient content is no barrier
to it, as 18 of the 32 records were from water with less
than 10 mg P04/m^.

Genus SPIRaULAX Kofoid

Diagnosis . Plate formula: 4ap, la, 6pr, 6g, 6s,
6po, Ip, lant. First apical does not touch girdle or an-
terior extension of ventral area. Posterior intercalary
wide. Sulcal plates: as, ra, rs, Is, i, ps. Ventral epi-
thecai pore absent.

Comparisons . Spiraulax is closely related to Gon -
yaulax . It has the same number of plates in all regions
of the theca, but the arrangement of the plates in the two
genera is significantly different. In Spiraulax there are
four apicals and only one anterior intercalary. In Gon -
yaulax pacifica and G. fusiformis there are only three
apicals, but there are two, instead of one, intercalaries.
The intercalary in Spiraulax is probably homologous
with a2 in Gonyaulax, whereas al of Gonyaulax is prob-
ably homologous with the third apical in Spiraulax . In
Gonyaulax the first apical extends either entirely to the
girdle or to the anterior end of the ventral area; in
Spiraulax this plate lies at the anterior edge of first pre-
cingular. The apical limb of ap2 and the ventral epithe-
cal pore foimd in Gonyaulax are absent in Spiraulax .

The hypothecal plate patterns are the same in the
two genera, although pi is usually narrower in Gonyau -
lax . The ventral area of Spiraulax is similar to that of
G. fusiformis , but G. pacifica has one more sulcal plate.

Spiraulax is less closely related to Acanthogonyau -
lax than to Gonyaulax . Acanthogonyaulax has nine, in-
stead of six, precingulars; it has no anterior intercala-
ries; the first apical does not extend to the girdle; and
the ventral area is unique (see pp. 5-6).

Remarks . The Carnegie material is similar to
that described and figured by Kofoid (1911b) from the
San Diego region. Our diagnosis of the pattern of the
major body plates agrees with that of Kofoid. The pat-
tern of the ventral area has not been reported before.

Kofoid (1911b) identified his material with that of
Murray and Whitting (1899) published under the name
Gonyaulax j olliffei . He considered this species to be
generically distinct from Gonyaulax and established the
new genus Spiraulax to include the one species. In our
opinion, Kofoid was justified in doing this for his own
material, which is specifically the same as ours. Gon-
yaulax j olliffei Murray and Whitting, however, is prob-
ably more closely related to G. fusiformis n.sp. than to
Spiraulax (see above). Since it is impossible to deter-
mine the plate pattern in this species without dissection,
the figures given by Murray and Whitting (1899, pi. 28,
fig. la, b) probably do not show the correct plate pat-
tern, as these authors apparently did not dissect their
specimens. The shape of the body of their species is
not that of Spiraulax . Although the first apical is shown
not reaching the ventral area or girdle, on the other
hand, the accompaniment of this condition in Spiraulax.
i.e., the intercalary touching the first precingular, is
not shown. In fact, no intercalary plates are shown at
all. The ventral epithecal pore and slender first apical
are not shown, but these are very easily overlooked in
undlssected specimens. In G. fusiformis the presence
of the slender first apical would never be suspected
without dissection.

FAMILY GONYAULACACEAE

55

Spiraulax kofoidii new name
(Figure 66)

Spiraulax j olliffei Kofoid, 1911b, pp. 296-298, pi. 19,
figs. 1-5. Forti. 1922, p. 82, pi. 6, fig. 71. not
Gonyaulax j olliffei Murray and Whitting, 1899, p.
324, pi. 28, fig. la, b.

Dimensions . Length of body (IJ, excluding antapi-
cal spine, 123 (101-160) microns. Diameter at girdle
(d) 79 (71-105) microns. Length of antapical spine 10
(0-18) microns. Width of girdle 5 to 6 microns. Twenty-
nine specimens were measured.

Shape . Body broadly fusiform. The j/d ratio is
1.54 (1.40-1.77). Epitheca prolonged as an apical horn
extending 0.75 transdiameter from proximal end of gir-
dle. Hypotheca also extends as a horn but is shorter
than epitheca; length 0.46 transdiameter, measured
from distal end of girdle. Antapical horn terminates in
a stout spine about 2.5 girdle widths long; in strongly
sculptured specimens sometimes so heavy thi^t it ap-
pears as a continuation of the body proper. Kofoid' s
(1911b, pi. 19) specimen does not show the spine al-
though he indicates it in his diagnosis. In ventral view
(fig. 660) epitheca usually somewhat concave on left side
but with prominent hump on right side, although Kofoid's
figure does not show much convexity on right side. Hy-
potheca has concavity on right side with hump on left
side. In apical view body almost circular except for
Indentation at sulcus, where girdle is depressed about
2 girdle widths (fig. 66D, E). Girdle approximately
equatorial, sinistral, displaced from 3 to 4 girdle
widths; deep excavation obscured by heavy sculpturing;
no overhang.

Ventral area elongate, slightly sigmoid, narrow in
middle but expanded at both ends (fig. 66 A, G). It ex-
tends into epitheca about 2.5 girdle widths. Between
girdle ends it is extremely narrow but posteriorly it
flares out into an elliptical flat area almost 2.5 girdle
widths wide, then narrows somewhat to antapex. Flagel-
lar pore narrow, elongate, extending from posterior
margin of proximal end of girdle to anterior margin of
distal end.

Plate pattern . First and fourth apicals ventral;
comparatively small. Second and third apicals large
and dorsal (fig. 66C, E, G).

Apical plates separate easily and preserved speci-
mens are usually found with apicals parted. No apical
platelet found in our material, but this may be due to its
ready loss during the parting of the apicals. First api-
cal does not extend to girdle but terminates at anterior
edge of prl. Anterior intercalary large, lying between
ap4 and pr6 and part of pr5. First precingular large,
extending a quarter of the way around left side of body.
Other precingulars subequal in size, the third and
fourth being the smallest.

The six girdle plates subequal in length except the
sixth, which is much longer than the rest. Positions of
sutures between girdle plates indicated by arrows in
figure 66E. The six postcingulars subequal in size ex-
cept the first, which is small and borders flagellar pore.
Posterior intercalary is broad, lies between pol to po3,
and antl, and borders middle third of left edge of ven-
tral area. Antapical plate large, forming distal part of
conical antapical horn. Posterior part of ventral area
set into its ventral face.

Ventral area composed of six plates: a large pos-
terior plate, a medium-sized anterior plate, and four

small intermediate plates (fig. 66A, B). Anterior plate
forms anterior margin of flagellar pore and extends into
epitheca almost halfway up side of anterior intercalary,
where it ends in a point. It has an arm which extends
posteriorly along anterior part of left edge of the pore.
The rest of right edge of the pore is formed by right ac-
cessory sulcal plate; the right sulcal plate barely touch-
es the pore. Left sulcal plate forms only posterior edge
of pore. Left edge of pore formed by first postcingular
plate. Intercalary sulcal plate lies between posterior
and right sulcal plates. The posterior sulcal plate
forms a large elliptical area on hypotheca. Most of the
sulcal plates are rotated on their long axes or are dis-
torted in the formation of the deep sulcus so that their
broadest aspects are not seen in ventral view. Figure
66B shows the sulcal plates in their broadest aspects.

Thecal wall. All our specimens are thick-walled,
but Kofoid (1911b) found thin-walled individuals. Body
of thinner individuals covered with a definite reticula-
tion with rounded meshes; but in heavier specimens,
this type of differentiation gives way to a very thick wall
with fairly regularly spaced pits. Kofoid states that
these pits have minute pores in the bottom, but these
were not detected among the Carnegie specimens under
the oil immersion objective. Ventral epitheca! pore ab-
sent. Surface sculpturing weak or lacking along plate
sutures; sometimes there is here a zone of smooth the-
cal wall more than a girdle width wide. Ridges or lists
along body sutures absent except at dorsal sutures of
apical plates, where very small lists occur. Girdle
plates with two rows of polygons or pits. Posterior sul-
cal plate reticulate or pitted. Pits and pores occur on
anterior and intercalary sulcal plates. Left and right
sulcal plates bear only pores; right accessory sulcal
plate is entirely smooth.

The anterior part of the first apical plate is bent
into a U-shaped trough with concavity facing inward (fig.
66E). In this manner the apex is formed almost entirely
by the first apical alone. When a specimen is viewed
ventrally, the sides of this trough appear as two dark
lines, so that the area between is light by contrast.
Kofoid interpreted this as a notch extending from the
apex and covered by a thin membrane, and suggested
its similarity to a structure in the first apical of Peri-
dinium . This is, however, an optical illusion which can
be dispelled by examining the separated apical plate in
apical view. The structure in Peridinium, moreover,
is quite different from this. In that genus there is a dis-
tinct linear plate, the ventral apical platelet, which lies
between the apex and the anterior end of the first apical
plate (see p. 16).

All sutures, including those of girdle and ventral
area, formed as rabbet joints with underlapping mem-
branes as in Peridinium (see p. 10). The membranes
of the girdle plates do not underlap the body plates, but
lie against the cingular lists, which are attached to the
body plates (m, fig. 66F). Striated intercalary zones
were not found.

Lists. Girdle lists about 1 girdle width wide; very
thick in thick-walled individuals, so that it is difficult
to distinguish them from body wall. In thinner individ-
uals, lists are strengthened by regularly spaced, stout
spines running out from body wall almost to edge of
lists. In heavier individuals, these spines may be
branched or form a reticulation. Sulcal Usts well de-
veloped. Right anterior sulcal list occurs along left
edge of precingular 6 and joins anterior girdle list. Left

56

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

and right posterior sulcal lists 2 girdle widths wide.
They do not extend to posterior end of ventral area, but
end about halfway down posterior sulcal plate (fig. 66G).
Sulcal lists quite evident in lateral view (fig. 66D).
Right sulcal list is attached to po6; the left is in two
parts, attached posteriorly to p and anteriorly to pol.
The portion of the ventral area which is free of lists
(the posterior part) is limited to the region bordered by
the antapical plate. Left list usually without structural
differentiation, but the right has short ribs or reticula-
tions at its base. Antapical spine thick, solid, irregu-
larly furrowed, about 2.5 girdle widths long.

Historical . This species was first reported by
Kofoid (1911b), who identified his material with Gonyau -
lax j oUiffei Murray and Whitting (1899) and assigned it
to the new genus Spiraulax . Since, in our opinion, Mur-
ray and Whitting's specimens do not belong to Spiraulax
(see p. 52), we are here assigning a new name to Ko-
foid's species, Spiraulax kofoidii new name.

Distribution . The references of Schroder (1900)
and Karsten (1907) to Gonyaulax j olliffei Murray and
Whitting for the Mediterranean and Indian oceans, re-
spectively, should not be accepted, since the figures of
Murray and Whitting have not yet been positively identi-
fied. The records of Spiraxilax j olliffei Kofoid of Pavil-
lard (1931) and of Matzenauer (1933), however, probably
refer to the present species. Pavillard found it in the
Atlantic and Mediterranean; Matzenauer in the Indian
Ocean. Forti's (1922) records for the Mediterranean
are not substantiated by drawings as his drawings are
copies.

In the Carnegie collections Spiraulax kofoidii was
found at most of the tropical stations. It occurred at
80 stations: 12 in the Atlantic and 68 in the Pacific.
There are 162 records of occurrence, with 119 rare, 39
occasional, and 4 common. The species was found less
commonly with increase in depth, with 66 records for
the siirface, 51 for 50 meters, and 45 for 100 meters.
There are 39 pump records and 123 net records. The
species was found in both hemispheres and in all months
of the year, except June and July.

The species Is widely distributed over tropical and
subtropical stations, although the records are not contin-
uous. In the Atlantic it occurred in the Gulf Stream as
far north as 38° north (station 1, surface temperature
24° C). Otherwise it was not found north of 24° north in
that ocean (station 19, surface temperature 27° C). In
the Pacific it was found only to 26° north in the west
(station 110, surface temperature 24° C) but to 37°
north in the east (station 130, off California, surface
temperature 16°2 C). In the South Pacific it did not oc-
cur farther south than 35° south (station 62, surface
temperature 19° C). It was most abimdant north of
Easter Island and in the line of stations east and north
of the Samoan Islands.

The surface temperatures at the stations where it
occurred at any depth varied from 19° to 29°.3 C, ex-
cept for the one record off California (station 130),
where the temperature was 16°2. The hydrographlc
conditions in situ were as follows: temperature, 13°.l
to 29°2 C; saUnity, 33.4 to 37.1 o/oo; pH, 7.80 to 8.47;
phosphate, 2 to 178 mg PO^/m'.

The species is probably indigenous to the areas with
Rrater of low nutrient content as well as to richer tropi-
cal waters, as there are 59 records in water containing
less than 10 mg P04/m3.

Family CERATIACEAE Lindemann
Diagnosis. See Lindemann, 1928, p. 91.
Genus CERATIUM Schrank

Diagnosis . See Lindemann, 1928, p. 92.

Remarks . Although the genus Ceratium is one of
the commonest and most widespread of the peridinlans
and is usually the first genus to be reported from ex-
pedition collections, its thecal morphology is still as
poorly known as that of the rarer genera. In order to
contribute something toward the knowledge of the mor-
phology of the genus and to endeavor to find something
which might throw light on the relationships of Cerati -
um to other genera, C. pavlllardii was selected for
study and subjected to a morphological analysis.

That this analysis was not so successful as in the
case of the other genera is not discouraging. Sufficient
knowledge was gained to indicate that such studies with-
in this interesting genus may be quite helpful in solving
some of the systematic problems and in arriving at a
proper imderstanding of relationships.

Ceratium arcticum was also dissected, but in this
species no trace of the ventral area had been preserved,
so that only the grosser features could be determined.
For this reason it is not reported here except as re-
ferred to under "Comparisons" under C. pavlllardii .

Ceratium pavlllardii Jorgensen
(Figure 67)

Ceratium pavlllardii Jorgensen, 1911a, p. 74, figs. 157A,
B, 158. Jorgensen, 1920, p. 92, fig. 83.

Ceratium yultur Pavillard, 1905, p. 54, pi. 1, fig. 2.

Ceratium tripos var. macroceras f . undulata Schroder,
1900, pi. 1, fig. 17m [not fig. 17K, L].

Diagnosis . Diameter (d) 78 (60-90) microns. Api-
cal horn more or less straight. Base of right antapical
horn extends laterally from body. Base of left antapical
horn bent abruptly anteriorly; sometimes there is a
short posterior extension before the turn. Otherwise no
posterior extension of antapicals. Antapical horns ex-
tend laterally to anteriorly.

Plate pattern . First apical with long margin on
ventral area; fourth apical with very short margin on
area.

Girdle plates four. The functional girdle probably
includes only the first three of these. First and fourth
girdle plates short, ventral; second and third long, dor-
sal. Suture gl/g2 in line with sutures prl/pr2 and
pol/po2. First and second plates regular in outline.
Third plate with distal end hammer-shaped (fig. 67D, F),
probably marking end of girdle proper, as girdle lists
end at this point. Fourth girdle plate peculiarly modi-
fied at Its distal end to form the concave roof of the
horn trough (fig. 67E, G).

Fifth postcingular, which forms ventral half of
right antapical horn, is molded at its proximal end to
form the horn trough (fig. 67G). In chains this trough
encloses anterior part of apical horn of adjacent spec-
imen immediately posterior. It is found in all speci-
mens, since all specimens form at least temporary
chains at division.

Ventral area composed of a numJser of extremely

FAMILY CERATIACEAE

57

thin, hyaline plates. Most of area anterior to girdle
covered by one large plate, the largest of the area (fig.
671). This plate is bordered along most of its margin
with a line of closely spaced minute tubercles. The rest
of the plate is covered with fairly regularly spaced tu-
bercles of larger size. At left side of this plate there
is a long, narrow, smooth plate. Ventral area posterior
to girdle composed for the most part of two smooth
plates. On the right side these are shorter than the an-
terior plate because of the projection of the horn trough
into the ventral area. The above four plates were each
dissected from the others, so that their occurrence as
distinct integral parts is well established. They include
all the plates of the right side of the ventral area.
There are other plates, however, on the left side. The
number and position of these as well as the exact loca-
tion of the flagellar pore or sulcus could not be deter-
mined. The plates in this region are extremely mem-
branaceous and nothing regarding their true shape or
orientation could be ascertained.

Comparisons . Our analysis of the ventral area of
C. pavillardii agrees in part with that of Entz (1927) for
a number of fresh-water species. Entz also found that
most of the area is made up of three large plates. In
his species, however, the shapes and relative sizes of
these plates varied considerably in different species.
It is probable, however, that the presence of these three
plates is characteristic of all species of Ceratium , both
fresh- water and marine.

In regard to the other features of the ventral area,
no analysis has been completely satisfactory. Entz
shows for most species two small plates at the left side
of the area alongside the longitudinal furrow. The na-
ture of this furrow or the position of the flagellar pore,
however, must still be considered uncertain.

Entz's analysis of the right side of the ventral area
and distal end of girdle is also unsatisfactory, so that no
direct comparison can be made with our analysis of that
region in C. pavillardii .

Our own analysis of C. arctlcum indicates that there
is probably considerable variation among the species in
respect to this region, so that the condition of C. pavil -
lardii cannot be considered representative of the entire
genus. In C. arcticum the fourth girdle plate is molded
into a cap for the horn trough as in C. pavillardii, but

the shape of the distal end of the third girdle plate is
regular, not hammer-shaped. Furthermore, there is a
continuation of girdle lists, or at least ridges, to the
ventral area, so that the distal end of the girdle proper
may be said to extend entirely to the ventral area, in
marked contrast with the condition in C. pavillardii .

Chain formation . Ceratium pavillardii is often
found in chains of several individuals. For this reason
the structure of the end of the apical horn and the horn
trough of the body is of particular interest. The end of
the apical horn is covered by a small platelet, the api-
cal platelet. It is pierced in the center by a large pore.
In chain specimens (except in the anterior cell) this
platelet, along with the ends of the apical plates, is very
much thickened and convoluted, so that a knobby process
is formed which holds the end of the horn fast in the
socket of the top of the horn trough of the anterior spec-
imen. This socket in the anterior specimen is formed
mostly by the fourth girdle plate. Specimens not in
chains have neither the knobby apical horn nor the deep
socket at the end of the horn trough. Specimens in
chains, with the exception of the apical cell, have much
shorter apical horns. Perhaps a time factor operates
here. It is suggested that, after division, if the cells
separate immediately, there is a growth at the end of
the apical horn which results in an increase in the length
of the horn, whereas, if the specimens remain connected
for a short length of time, this growth results, not in
increase in the length of the horn, but in formation of a
knob at the end of the horn which acts to fasten the two
cells together so that by the time cell growth is com-
pleted the two cells are firmly secured to each other.
Chain formation, on this basis, then, would depend on
the formation of the knob during a short critical period
while the mother cell undergoes division.

Distribution . The genus Ceratium is distributed
over all the oceans of the world and is one of the most
valuable genera of the peridinians for distributional
studies. Not only are there cold- and warm-water spe-
cies, but many species show minor phenotypic variations
which are useful in tracing dynamic conditions.

The discussion of the distribution of aU the species
of Ceratium of the Carnegie collection constitutes an-
other report. Since the distribution of C. pavillardii is
included in that work, it is not reported here.

TABLES 3-23

TABLES OF DISTRIBUTIONAL AND ENVIRONMENTAL RECORDS
(For tables 1 and 2 see page 7)

Abbreviations and Numerical Equivalents used in Tables

For Relative Abundance
a (abundant) indicates over 50 individuals oc (occasional) from 11 to 25 individuals

c (common) from 25 to 50 individuals r (rare) from 6 to 10 individuals

For Apparatus
n = sample taken by net p = sample taken by pump

Values enclosed in parentheses and marked by asterisk ( )* are interpolated

DISTRIBUTIONAL AND ENVIRONMENTAL RECORDS

61

Table 3. Distributional and environmental records for Peridinium depressum Bailey

Station

Sample

Depth
(m)

RelaUve
abundance

Apparatus

Date

Temperature
(°C)

Salinity
(o/oo)

PH

^?4 3
mg/m">

Atl

antic

3

19

100

oc

n

5/21/28

13.65

35.89

8.10

48

6

37

100

r

n

5/31/28

11.30

35.55

8.08

40

6b

45

c

n

6/ 2/28

(12.44)
(12.44)

(35.55)

(8.15)

(21)a

46

oc

n

6/ 2/28

(35.55) (8.15)

(2l)a

6e

52

r

n

7/ 8/28

....

6f

53

r

n

7/ 9/28

....

6g

54

oc

n

7/10/28

....

7

56

r

n

7/13/28

8.92

35.21

8.08

34

57

50

a

n

7/13/28

8.16

35.25

8.03

47

58

100

a

n

7/13/28

8.12

35.24

8.04

57

10

68

oc

n

7/30/28

10.94

34.95

8.08

28

69

50

oc

n

7/30/28

9.86

34.94

8.04

34

70

100

oc

n

7/30/28

6.56

35.02

7.95

52

11

73

oc

n

8/ 1/28

10.67

34.91

8.06

27

75

oc

p

8/ 1/28

10.67

34.91

8.06

(27)''

11a

78

oc

n

8/ 2/28

(10.67)

(34.91)

(8.06)

12

79

oc

n

8/ 5/28

8.44

33.65

8.10

27

80

50

c

n

8/ 5/28

3.95

34.74

7.96

78

81

100

c

n

8/ 5/28

3.46

34.87

7.91

95

82

c

p

8/ 5/28

8.44

33.65

8.10

27

13

83

r

n

8/ 7/28

11.27

32.68

8.09

19

85

50

a

n

8/ 7/28

-1.64

33.40

7.87

59

86

100

a

n

8/ 7/28

-1.10

33.62

7.87

63

87

oc

P

8/ 7/28

11.27

32.68

8.09

19

14

91

100

r

P

8/ 9/28

14.02

35.59

8.06

34

94

100

oc

n

8/ 9/28

14.02

35.59

8.06

34

95

50

oc

n

8/ 9/28

14.95

35.10

8.18

16

15

97

r

p

8/11/28

24.81

36.39

8.21

11

101

50

r

n

8/11/28

20.00

36.48

8.21

8

102

100

oc

n

8/11/28

18.50

36.45

8.19

15

16

107

50

r

n

8/13/28

23.64

36.41

8.23

8

108

100

oc

n

8/13/28

19.62

36.48

8.17

13

18

118

50

r

n

8/17/28

22.12

36.82

8.24

5

19

123

50

oc

n

8/20/28

25.31

37.15

8.27

5

20

129

50

r

n

8/22/28

25.72

36.60

8.26

3

130

100

r

n

8/22/28

22.56

36.73

8.19

5

21

137

100

r

n

8/24/28

20.93

36.75

8.20

7

22

144

100

r

n

8/27/28

17.50

36.10

7.99

123

24

153

100

r

p

8/31/28

15.6

35.6

7.96

99

155

50

r

n

8/31/28

23.1

36.0

8.14

8

25

162

100

r

n

9/ 3/28

14.6

35.7

7.93

121

28

177

50

r

n

9/11/28

26.7

36.3

8.26

4

Pacific

111

668

oc

n

6/ 3/29

20.1

34.5

8.18

5

671

oc

P

6/ 3/29

20.1

34.5

8.18

5

112

675

50

r

n

6/ 5/29

21.7

34.6

8.23

7

113

680

oc

n

6/25/29

24.2

34.5

8.25

5

114

686

r

n

6/27/29

19.9

34.3

8.15

7

688

100

r

n

6/27/29

13.0

34.5

8.00

91

689

r

P

6/27/29

19.9

34.3

8.15

7

115

692

r

n

6/29/29

20.6

34.6

8.19

4

693

50

r

n

6/29/29

17.5

34.6

8.12

17

694

100

oc

n

6/29/29

15.6

34.6

8.08

27

115a

700

c

n

6/30/29

(18.0)
(18.0)

(34.3)
34.3)

(8.18
(8.18

(4 *

702

oc

n

6/30/29

(4)*

116

703

50

c

n

7/ 1/29

10.6

33.8

8.11

23

706

50

oc

p

7/ 1/29

10.6

33.8

8.11

23

704

100

oc

n

7/ 1/29

6.7

33.8

. .

707

100

oc

p

7/ 1/29

6.7

33.8

117

710

100

r

n

7/ 3/29

8.8

34.1

7.98

84

713

100

r

P

7/ 3/29

8.8

34.1

7.98

84

118

714

oc

P

7/ 5/29

10.2

33.6

8.21

90

716

100

r

n

7/ 5/29

6.1

33.8

7.94

114

718

50

r

p

7/ 5/29

8.2

33.7

8.21

92

119

720

oc

n

7/ 7/29

6.9

33.0

7.96

142

723

oc

p

7/ 7/29

6.9

33.0

7.96

142

121

732

oc

n

7/11/29

7.5

32.9

7.98

141

735

r

p

7/11/29

7.5

32.9

7.98

141

734

100

r

n

7/11/29

2.1

33.2

7.86

184

122

738

r

n

7/13/29

8.2

32.8

7.98

130

741

r

p

7/13/29

8.2

32.8

7.98

130

739

50

r

n

7/13/2S

3.6

33.1

7.94

142

743

100

r

P

7/13/29

2.4

33.1

7.90

161

^ Surface values for station 6.

^ Surface values for station 1 1 .

62 STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES
Table 4. Distributional and environmental records for Peridinium depressum var. parallelum Broch

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature
(°C)

SaUnlty
(o/oo)

PH

PO4

mg/m3

Atl

inti c

6h

55

c

n

7/11/28

. . .

, ,

8

59

oc

n

7/15/28

10.32

35.23

7.93

13

60

50

oc

n

7/15/28

9.08

35.25

7.95

27

61

100

c

n

7/15/28

8.44

35.25

7.95

54

9

64

c

n

7/28/28

11.12

35.14

8.08

20

65

50

oc

n

7/28/28

8.06

35.11

7.96

55

66

100

oc

n

7/28/28

7.62

35.11

7.98

56

11

73

oc

n

8/ 1/28

10.67

34.91

8.06

27

74

50

c

n

8/ 1/28

7.01

34.97

7.92

63

76

50

r

p

8/ 1/28

7.01

34.97

7.92

63

12

82

oc

p

8/ 5/28

8.44

33.65

8.10

27

13

85

50

c

n

8/ 7/28

-1.64

33.40

7.87

59

87

r

p

8/ 7/28

11.27

32.68

8.09

19

13a

89

oc

n

8/ 9/28

(21.18)

(35.23)

(8.18)

(11)^

14

94

100

oc

n

8/ 9/28

14.02

35.59

8.06

34

15

102

100

r

n

8/11/28

18.45

36.45

8.19

15

16

108

100

oc

n

8/13/28

19.62

36.48

8.17

13

18

118

50

r

n

8/17/28

22.4

36.8

8.24

5

21

134

100

r

p

8/24/28

21.0

36.8

8.20

7

137

100

r

n

8/24/28

21.0

36.8

8.20

7

23

149

50

r

n

8/29/28

20.9

36.0

8.14

13

Pacific

128

773

oc

n

7/25/29

16.4

33.0

8.12

29

130

784

r

P

9/ 4/29

16.2

33.4

8.34

36

782

50

c

n

9/ 4/29

11.7

33.4

8.26

83

785

50

c

P

9/ 4/29

11.7

33.4

8.26

83

783

100

oc

n

9/ 4/29

8.8

33.7

8.06

176

^ Surface values for station 14.

Table 5. Distributional and environmental records for Peridinium depressum var. convexius n.var.

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature

CO

Salinity
(0/00)

pH

mg/mJ

Atlantic

lb

8

100

oc

n 5/16/28

(20.00)

(36.50)

(8.15)

(30)*

14

92

50

r

p 8/ 9/28

14.95

35.10

8.18

16

16

108

100

r

n 8/13/28
Pacific

19.62

36.48

8.17

13

39

226

50

r

n 11/ 6/28

16.3

34.6

7.92

48

69

424

oc

n 1/12/29

21.1

35.2

8.12

62

425

50

oc

n 1/12/29

17.4

35.1

7.99

151

426

100

oc

n 1/12/29

14.6

34.8

7.86

198

427

oc

p 1/12/29

21.1

35.2

8.12

62

428

50

r

p 1/12/29

17.4

35.1

7.99

151

429

100

oc

p 1/12/29

14.6

34.8

7.86

198

70

431

oc

n 1/13/29

21.2

35.1

8.05

103

432

50

oc

n 1/13/29

15.4

35.0

7.88

178

433

100

oc

n 1/13/29

12.6

34.8

7.68

233

434

c

p 1/13/29

21.2

35.1

8.05

103

435

50

r

p 1/13/29

15.4

35.0

7.88

178

436

100

r

p 1/13/29

17.6

34.8

7.68

233

109

656

100

oc

n 5/29/29

27.4

35.0

8.23

3

659

100

r

p 5/29/29

27.4

35.0

8.23

3

110

662

50

r

n 5/31/29

18.4

34.8

8.16

7

663

100

oc

n 5/31/29

17.9

34.7

8.14

11

665

50

oc

p 5/31/29

18.4

34.8

8.16

7

111

668

oc

n 6/ 3/29

20.1

34.5

8.18

5

669

50

oc

n 6/ 3/29

19.4

34.6

8.17

5

670

100

oc

n 6/ 3/29

18.2

34.7

8.13

13

112

675

50

oc

n 6/ 5/29

21.7

34.6

8.23

7

676

100

oc

n 6/ 5/29

19.8

34.7

8.20

8

678

50

r

p 6/ 5/29

21.7

34.6

8.23

7

116

704

100

r

n 7/ 1/29

6.7

33.8

. . .

. .

DISTRIBUTIONAL AND ENVIRONMENTAL RECORDS

63

Table 6. Distributional and environmental records for Peridinium claudicanoides n.sp.

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature
(°C)

Salinity
(o/oo)

PH

mg/m>>

Atl.

intic

1

1

oc

n

5/12/28

24.17

36.23

8.16

34

la

5

r

n

5/14/28

< • • •

2

14

c

n

5/18/28

20.50

36.40

8.23

58

3

19

100

r

n

5/21/28

13.79

35.91

8.10

50

32

196

IQO

r

n

10/ 5/28

22.2

36.4

8.10

30

Pacific

35

204

50

r

n

10/26/28

16.8

34.7

7.92

138

35a

208

r

n

10/26/28

(27.0)
(27.0)

(30.0)
(30.0)

(8.25)

(15)*

35b

212

r

n

10/28/28

(8.25)

(15)*

40

229

r

n

11/ 8/28

22.2

33.7

8.21

24

230

50

r

n

11/ 8/28

15.3

34.9

7.87

161

231

100

r

n

11/ 8/28

13.9

35.0

7.85

159

232

r

P

11/ 8/28

22.2

33.7

8.21

24

233

50

r

P

11/ 8/28

15.3

34.9

7.87

161

Table 7. Distributional and environmental records for Peridinium oceanicum

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature

rc)

Salinity
(o/oo)

pH

mg/m^

Atl

mtic

9

64

c

n

7/28/28

11.12

35.14

8.08

20

65

50

a

n

7/28/28

8.06

35.11

7.96

55

66

100

c

n

7/28/28

7.62

35.11

7.98

56

10

68

oc

n

7/30/28

10.94

34.95

8.08

28

69

50

c

n

7/30/28

9.86

34.94

8.04

34

70

100

oc

n

7/30/28

6.56

35.02

7.95

52

11

73

c

n

8/ 1/28

10.67

34.91

8.06

27

74

50

c

n

8/ 1/28

7.01

34.97

7.92

63

75

oc

p

8/ 1/28

10.67

34.91

8.06

27

76

50

r

p

8/ 1/28

7.01

34.96

7.92

63

77

100

r

p

8/ 1/28

6.26

35.05

7.90

67

11a

78

r

n

8/ 2/28

(10.67)

(34.91)

(8.06)

(27)a

12

80

50

oc

n

8/ 5/28

3.95

34.74

7.96

78

15

102

100

oc

n

8/11/28

18.50

36.45

8.19

15

16

108

100

r

n

8/13/28

19.62

36.48

8.17

(4)b

20a

131

r

n

8/23/28

(26.57)

(36.28)

(8.32)

21

137

100

r

n

8/24/28

21.00

36.75

8.20

7

^ Surface values for station 11.

° Surface values for station 21.

Table 8. Distributional and environmental records for Peridinium oceanicum var. teneUum

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature
(°C)

Salinity
(o/oo)

pH

mg/m^

Atlantic

la

4
5

r
oc

n 5/14/28
n 5/14/28

lb

6
7
8

50

100

oc
oc

r

n 5/16/28
n 5/16/28
n 5/16/28

....

2

14

oc

n 5/18/28

20.50

36.40

8.23

58

3

20

oc

n 5/21/28

15.50

36.06

8.15

99

18

50

oc

n 5/21/28

14.66

35.96

8.19

30

19

100

r

n 5/21/28

13.65

35.89

8.10

48

6

36

50

oc

n 5/31/28

11.62

35.51

8.12

32

6a

46

oc

n 5/31/28

12.44)

(35.55)

(8.15;

iS^a

6b

44

oc

n 6/ 2/28

12.44

35.55)

'8.15

(21 a

45

c

n 6/ 2/28

12.44;

(35.55

8.15'

(21;^

6c

49

r

n 6/ 4/28

12.44)

(35.55'

8.15'

(21 a

8

60

50

a

n 7/15/28

9.08

35.25

7.95

27

61

100

oc

n 7/15/28

8.44

35.25

7.95

(11)"

13a

89

r

n 8/ 8/28

21.18)

(35.23)

(8.18

14

91

100

r

p 8/ 9/28

14.02

35.59

8.06

34

92

50

r

p 8/ 9/28

14.95

35.10

8.18

16

94

100

r

n 8/ 9/28

14.02

35.59

8.06

34

95

50

c

n 8/ 9/28

14.95

35.10

8.18

16

15

99

100

r

p 8/11/28

18.45

36.45

8.19

15

16

•107

50

oc

n 8/13/28

23.64

36.41

8.23

8

108

100

r

n 8/13/28

19.62

36.48

8.17

13

31

193

100

oc

n 10/ 3/28

22.56

35.51

8.19

28

64 STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

Table 8. Distributional and environmental records for
Peridinium oceanicum var. tenellum- -Continued

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature

Cc)

Salinity
(o/oo)

pH

P04-

mg/m^

Atlantic

--Concluded

32

195

50

r

n

10/ 5/28

27.2

36.0

8.24

2

Pacific

40

230

50

r

n

11/ 8/28

15.3

34.9

7.87

161

231

100

r

n

11/ 8/28

13.9

35.0

7.85

159

232

00

p

11/ 8/28

22.2

33.7

8.21

24

235

r

n

11/ 8/28

22.2

33.7

8.21

24

41

236

50

r

n

11/10/28

14.6

35.0

7.94

58

238

r

p

11/10/28

20.4

34.2

8.11

32

239

100

r

p

11/10/28

14.5

35.0

7.91

152

41a

240

oc

n

11/12/28

(18.7)
(18.7)

(34.7)

(8.06)

(45)-:
(45)

42

241

r

n

11/13/28

(34.7'

(8.06)

242

50

r

n

11/13/28

17.2

34.9

7.99

68

243

100

r

n

11/13/28

13.8

35.0

7.91

150

43

246

100

r

n

11/15/28

13.6

35.0

7.90

92

247

r

p

11/15/28

19.6

34.8

8.09

52

44

253

r

p

11/17/28

20.7

34.9

8.03

38

45

256

r

n

11/19/28

22.4

35.3

8.12

38

257

50

r

n

11/19/28

22.4

35.2

8.13

46

258

100

r

n

11/19/28

18.6

35.1

8.00

50

259

oc

p

11/19/28

22.4

35.3

8.12

38

260

50

r

p

11/19/28

22.4

35.2

8.13

46

46

261

oc

n

11/21/28

23.3

35.3

8.16

36

262

50

r

n

11/21/28

23.2

35.3

8.16

40

263

100

r

n

11/21/28

22.5

35.4

8.17

40

264

r

P

11/21/28

23.3

35.3

8.16

36

265

50

r

P

11/21/28

23.2

35.3

8.16

40

47

266

r

n

11/23/28

23.9

36.0

8.23

17

267

50

oc

n

11/23/28

23.8

36.0

8.23

20

268

100

oc

n

11/23/28

22.7

36.2

8.23

20

269

oc

P

11/23/28

23.9

36.0

8.23

17

48

273

100

oc

n

11/25/28

22.7

36.2

8.23

20

53a

310

r

n

12/10/28

58

346

100

r

p

12/20/28

14.3

34.4

8.10

40

61

364

50

oc

n

12/28/28

14.0

34.0

8.05

60

365

100

r

n

12/28/28

10.8

34.0

8.03

80

62

372

50

r

n

12/30/28

16.2

34.3

8.10

28

71

438

oc

n

2/ 6/29

23.5

35.2

8.13

58

439

50

oc

n

2/ 6/29

16.7

35.1

7.90

150

440

100

r

n

2/ 6/29

13.9

35.0

7.71

220

441

oc

P

2/ 6/29

23.5

35.2

8.13

58

72

445

100

r

n

2/ 6/29

13.9

35.0

7.71

220

73

450

oc

n

2/10/29

25.3

35.4

8.21

44

451

50

r

n

2/10/29

18.7

35.4

8.05

122

453

100

r .

n

2/10/29

14.7

35.0

7.80

178

74

458

100

r

n

2/12/29

15.4

35.1

7.80

175

75

462

r

n

2/14/29

22.8

35.8

8.18

44

76

467

r

n

2/16/29

23.4

35.9

8.15

50

471

50

r

p

2/16/29

22.1

35.9

8.14

42

77

472

oc

n

2/18/29

23.7

36.0

8.19

16

473

oc

p

2/18/29

23.7

36.0

8.19

16

474

50

oc

p

2/18/29

23.5

36.0

8.19

16

78

475

oc

n

2/20/29

24.6

36.0

8.17

32

476

50

r

n

2/20/29

23.8

36.1

8.14

32

477

100

oc

n

2/20/29

21.9

36.2

8.14

34

478

r

P

2/20/29
2/22/29

24.6

36.0

8.17

32

79

481

oc

n

25.2

36.0

8.17

34

482

oc

n

2/22/29

25.2

36.0

8.17

34

483

100

oc

n

2/22/29

21.8

36.2

8.13

45

484

r

P

2/22/29

25.2

36.0

8.17

34

485

50

r

P

2/22/29

24.5

36.1

8.17

34

80

486

oc

n

2/24/29

26.0

35.9

8.20

36

488

oc

P

2/24/29

26.0

35.9

8.20

36

81

491

oc

n

2/26/29

26.5

35.8

8.19

38

492

50

r

n

2/26/29

26.4

35.9

8.19

38

493

r

p

2/26/29

26.5

35.8

8.19

38

494

50

r

P

2/26/29

26.4

35.9

8.19

38

495

100

r

P

2/26/29

23.6

36.2

8.18

36

82

497

50

oc

n

2/28/29

27.2

36.3

8.21

34

97

574

oc

n

4/28/29

28.3

35.2

8.16

24

575

50

r

n

4/28/29

28.0

35.4

8.16

21

576

100

r

n

4/28/29

27.6

35.6

8.15

25

98

581

r

n

4/30/29

27.0

35.3

8.16

24

583

100

r

n

4/30/29

26.7

35.4

8.14

32

DISTRIBUTIONAL AND ENVIRONMENTAL RECORDS

65

Table 8. Distributional and environmental records for
Peridinium oceanicum var. tenellum--Concluded

Station

Sample

Deptii
(m)

Relative
abundance

Apparatus

Date

Temperature

rc)

Salinity
(o/oo)

pH

PO4 ,

mg/m3

Pac ific

--Concluded

98

584

r

p

4/30/29

27.0

35.3

8.16

24

588

100

r

p

4/30/29

26.7

35.4

8.14

32

99

589

r

n

5/ 2/29

27.9

34.9

8.21

12

590

50

r

n

5/ 2/29

•27.8

34.9

8.22

12

592

r

P

5/ 2/29

27.9

34.9

8.21

12

594

100

r

P

5/ 2/29

27.8

35.0

8.22

17

595

r

n

5/ 2/29

27.9

34.9

8.21

12

100

596

50

c

n

5/ 4/29

27.6

34.7

8.21

10

597

100

oc

n

5/ 4/29

27.6

34.7

8.22

12

115

693

50

oc

n

6/29/29

17.5

34.6

8.12

17

697

50

r

P

6/29/29

17.5

34.6

8.12

17

115a

700

r

n

6/30/29

(18.0)

(34.3)

(8.18)

(4)*

116

704

100

oc

n

7/ 1/29

6.7

33.8

117

709

50

oc

n

7/ 3/29

12.5

34.2

8.06

51

712

50

oc

P

7/ 3/29

12.5

34.2

8.06

51

127

767

oc

n

7/23/29

13.4

32.7

8.12

43

768

50

r

n

7/23/29

10.5

32.8

8.09

56

771

50

r

P

7/23/29

10.5

32.8

8.09

56

769

100

r

n

7/23/29

8.2

32.8

8.00

72

128

773

oc

n

7/25/29

16.4

33.0

8.12

29

776

oc

P

7/25/29

16.4

33.0

8.12

29

775

100

oc

n

7/25/29

10.2

33.2

8.06

46

130

783

100

r

n

9/ 4/29

8.8

33.7

8.06

176

792

r

p

9/ 4/29

16.2

33.4

8.34

36

131

788

r

n

9/ 6/29

19.3

33.4

8.34

793

r

P

9/ 6/29

19.3

33.4

8.34

151

938

50

r

n

9/ 6/29

18.3

34.4

152

945

50

r

n

10/27/29

14.2

34.5

7.87

'53

946

100

r

n

10/27/29

11.4

34.7

7.76

75

155

973

50

r

p

11/ 2/29

27.7

34.9

8.30

30

156

974

100

r

n

11/ 4/29

26.4

35.1

8.30

48

157

978

oc

n

11/ 6/29

27.1

35.3

8.27

47

979

50

r

n

11/ 6/29

27.1

35.2

8.32

60

980

100

r

n

11/ 6/29

26.8

35.5

8.30

64

158

983

r

n

11/ 8/29

28.2

35.6

8.34

36

984

50

r

n

11/ 8/29

28.2

35.6

8.39

50

985

100

r

n

11/ 8/29

27.6

35.9

8.39

48

159

990

r

n

11/11/29

28.6

35.7

8.37

15

991

50

r

n

11/11/29

28.5

35.7

8.39

15

992

100

r

n

11/11/29

28.0

35.7

8.37

23

^ Surface values for station 6. Surface values for station 14. <^ Values of station 42.

Table 9. Distributional and environmental records for Peridinium crassipes Kofoid

Station Sample

Depth

Relative
abundance

Apparatus

Date

Temperature
(°C)

Salinity
(0/00)

pH

jng/mf

35

204

50

r

36

213

r

37

218

50

r

221

50

r

40

234

100

r

41

237

100

oc

44

254

50

r

45

256

r

257

50

r

258

100

r

48

271

oc

272

50

r

273

100

r

49

277

r

49a

283

r

58

346

100

r

60

359

r

61

364

50

r

365

100

r

62

372

50

r

373

100

r

69

424

r

425

50

oc

426

100

oc

Pacific
10/26/28
10/30/28
11/ 1/28
11/ 1/28
11/ 8/28
11/10/28
11/17/28
11/19/28
11/19/28
11/19/28
11/25/28
11/25/28
11/25/28
11/27/28
11/28/28
12/22/28
12/22/28
12/28/28
12/28/28
12/30/28
12/30/28
1/12/29
1/12/29
1/12/29

16.8
26.5
18.8
18.8
13.9
14.5
20.4
22.4
22.4
18.6
23.6
23.6
22.7
23.4
(23.2)
12.3
12.3
14.0
10.8
16.2
13.1
21.1
17.4
14.6

34.7
31.6
34.5
34.5
35.0
35.0
34.9
35.3
35.2
35.1
36.4
36.4
36.3
36.2
(36.0)
34.1
34.1
34.0
34.0
34.3
34.2
35.2
35.1
34.8

7.92
8.23
8.00
8.00
7.85
7.91
8.04
8.12
8.13
8.00
8.23
8.24
8.26
8.27
(8.23)
8.05
8.05
8.05
8.03
8.10
8.06
8.12
7.99
7.86

138

16
121
121
159
152

34

38

46

50

13

16

16

13
(13)»

40

40

60

80

28

48

62
151
198

66 STUDIES m THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

Table 9. Distributional and environmental records for Peridinium crassipes Kofoid- -Continued

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature

Salinity
(o/oo)

PH

mg/m''

Pacific- -Continued

77

472

oc

n

2/18/29

23.7

36.0

8.19

16

78

477

100

r

n

2/20/29

21.9

36.2

8.14

34

84

506

50

r

n

3/ 4/29

27.5

36.4

8.21

24

86

517

50

r

n

3/ 9/29

27.4

36.2

8.29

17

97

574

oc

n

4/28/29

28.3

35.2

8.16

24

575

50

oc

n

4/28/29

28.0

35.4

8.16

21

576

100

oc

n

4/28/29

27.6

35.6

8.15

25

578

50

r

P

4/28/29

28.0

35.4

8.16

21

579

100

r

P

4/28/29

27.6

35.6

8.15

25

98

583

100

oc

n

4/30/29

26.7

35.4

8.14

32

584

oc

P

4/30/29

27.0

35.3

8.16

24

99

589

r

n

5/ 2/29

27.9

34.9

8.21

12

590

50

oc

n

5/ 2/29

27.8

34.9

8.22

12

591

100

oc

n

5/ 2/29

27.8

35.0

8.22

17

595

oc

n

5/ 2/29

27.9

34.9

8.21

12

100

596

50

oc

n

5/ 4/29

27.6

34.7

8.21

10

597

100

oc

n

5/ 4/29

27.6

34.7

8.22

12

602

100

r

P

5/ 4/29

27.6

34.7

8.22

12

101

603

oc

n

5/ 7/29

26.3

34.7

8.24

8

604

50

oc

n

5/ 7/29

26.2

34.7

8.24

8

605

100

oc

n

5/ 7/29

25.2

35.1

8.25

8

102

609

oc

n

5/ 9/29

25.8

35.0

8.24

8

610

50

oc

n

5/ 9/29

25.8

35.0

8.24

8

103

615

oc

n

5/11/29

26.0

35.0

8.25

5

616

50

oc

n

5/11/29

25.8

35.2

8.25

5

617

100

r

n

5/11/29

24.8

35.2

8.25

5

620

100

r

P

5/11/29

24.8

35.2

8.25

5

104

621

oc

n

5/13/29

26.1

35.2

8.24

7

623

100

oc

n

5/13/29

25.3

35.3

8.21

7

105

627

50

oc

n

5/15/29

26.9

34.9

8.23

5

628

SO

r

n

5/15/29

26.9

34.9

8.23

5

629

100

oc

n

5/15/29

25.2

35.1

8.23

5

106

633

r

n

5/17/29

27.2

35.0

8.23

5

634

50

oc

n

5/17/29

27.0

35.0

8.23

5

635

100

oc

n

5/17/29

25.6

35.1

8.23

5

107

639

oc

n

5/19/29

28.0

34.4

8.23

5

640

oc

n

5/19/29

28.0

34.4

8.23

5

641

r

n

5/19/29

28.0

34.4

8.23

5

132

789

50

oc

n

9/ 8/29

17.6

33.9

8.33

19

799

100

oc

n

9/ 8/29

14.3

33.4

8.30

16

133

805

50

r

n

9/10/29

20.8

34.7

8.37

7

134

809

50

r

n

9/12/29

19.8

34.6

8.34

6

810

100

r

n

9/12/29

18.1

34.6

8.34

6

817

100

r

P

9/12/29

18.1

34.6

8.34

6

135

821

50

r

n

9/14/29

21.5

35.0

8.37

5

822

100

r

n

9/14/29

18.7

34.8

8.34

5

136

827

r

n

9/16/29

24.6

35.4

8.37

3

828

50

oc

n

9/16/29

21.4

35.1

8.39

3

829

100

oc

n

9/16/29

18.6

35.0

8.39

3

139

850

50

oc

n

9/22/29

25.8

34.9

8.31

6

140

857

50

r

n

10/ 3/29

26.9

35.0

8.39

7

862

100

r

P

10/ 3/29

25.5

35.0

8.34

7

141

864

r

n

10/ 5/29

25.9

35.2

8.34

5

865

50

r

n

10/ 5/29

24.8

35.3

8.34

5

142

874

100

oc

n

10/ 7/29

16.6

34.4

8.27

7

149

921

50

r

n

10/21/29

23.3

35.0

8.37

6

150

929

oc

n

10/25/29

25.6

34.7

8.39

7

930

50

r

n

10/25/29

22.8

34.8

8.35

10

931

100

r

n

10/25/29

19.6

34.6

8.32

11

151

937

r

n

10/26/29

26.0

34.0

938

50

r

n

10/26/29

18.3

34.4

.

939

100

r

n

10/26/29

12.5

34.6

942

50

r

P

10/26/29

18.3

34.4

944

r

n

10/27/29

27.4

33.7

8.35

20

152

946

100

r

n

10/27/29

11.4

34.7

7.76

75

153

951

r

n

10/29/29

28.1

34.2

8.47

7

955

r

P

10/29/29

28.1

34.2

8.47

7

952

50

r

n

10/29/29

28.2

34.2

8.40

7

953

100

r

n

10/29/29

25.3

34.8

7.93

21

154

959

50

r

n

10/31/29

28.2

34.2

8.40

7

960

100

r

n

10/31/29

25.3

34.8

7.93

21

155

965

oc

n

11/ 2/29

27.8

34.9

8.29

29

966

50

oc

n

11/ 2/29

27.7

34.9

8.30

30

967

100

r

n

11/ 2/29

27.2

35.0

8.30

35

156

973

50

oc

n

11/ 4/29

27.0

35.1

8.37

46

974

100

r

n

11/ 4/29

26.4

35.1

8.30

48

DISTRIBUTIONAL AND ENVIRONMENTAL RECORDS

67

Table 9. Distributional and environmental records for Peridinlum crassipes Kofoid- -Concluded

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature
(°C)

Salinity
(o/oo)

PH

mg/m"'

Pacific --Concluded

157

978

oc

n

11/ 6/29

27.1

35.3

8.27

47

979

50

DC

n

11/ 6/29

27.1

35.2

8.32

60

980

100

oc

n

11/ 6/29

26.8

35.5

8.30

64

158

983

r

n

11/ 8/29

28.2

35.6

8.34

36

985

100

OC

n

11/ 8/29

27.6

35.9

8.39

48

160

1002

50

r

n

11/13/29

28.6

35.6

8.39

15

Table 10. Distributional and environmental records for Peridinium truncatum n.sp.

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature

Cc)

Salinity
(o/oo)

pH

mg/m^

P acif ic

35

203

oc

n

10/26/28

27.4

29.7

8.31

15

204

50

r

n

10/26/28

16.8

34.7

7.92

138

205

100

r

n

10/26/28

14.4

34.9

7.88

189

206

oc

p

10/26/28

27.4

29.7

8.31

15

35a

208

oc

n

10/26/28

(27.0)

(30.0)

(8.26)

'>^ll*

211

c

n

10/26/28

27.0

(30.0)
(30.0)

(8.26)

(15)*

212

oc

n

10/26/28

(27.0)

(8.26)

(15)*

36

213

oc

n

10/30/28

26.5

31.6

8.23

16

214

50

r

n

10/30/28

18.5

34.5

8.03

122

215

100

r

n

10/30/28

14.4

34.9

7.85

149

37

217

oc

n

11/ 1/28

27.1

31.7

8.28

15

218

50

r

n

11/ 1/28

18.8

34.5

8.00

121

219

100

r

n

11/ 1/28

15.1

34.9

7.82

153

42

241

r

n

11/13/28

18.7

34.7

8.06

45

80

486

r

n

2/24/29

26.0

35.9

8.20

36

91

541

50

r

n

3/27/29

28.4

35.4

8.29

28

92

546

50

oc

n

3/29/29

28.4

35.4

8.29

28

95

564

100

r

n

4/24/29

28.5

35.4

8.22

21

96

569

50

r

n

4/26/29

29.2

35.3

8.23

12

97

575

50

oc

n

4/28/29

28.0

35.4

8.16

21

578

50

r

p

4/28/29

28.0

35.4

8.16

21

99

589

r

n

5/ 2/29

27.9

34.9

8.21

12

590

50

r

n

5/ 2/29

27.8

34.9

8.22

12

592

r

p

5/ 2/29

27.9

34.9

8.21

12

593

50

r

p

5/ 2/29

27.8

34.9

8.22

12

595

oc

n

5/ 2/29

27.9

34.9

8.21

12

100

596

50

oc

n

5/ 4/29

27.6

34.7

8.21

10

104

623

100

r

n

5/13/29

25.3

35.3

8.21

7

105

629

100

r

n

5/15/29

25.2

35.1

8.23

5

112

675

50

r

n

6/ 5/29

21.7

34.6

8.23

7

137

837

50

r

n

9/18/29

24.4

35.1

8.34

4

141

865

50

oc

n

10/ 5/29

24.8

35.3

8.34

5

151

942

50

r

P

10/26/29

18.3

34.4

155

965

oc

n

11/ 2/29

27.8

34.9

8.29

29

966

50

oc

n

11/ 2/29

27.7

34.9

8.30

30

967

100

oc

n

11/ 2/29

27.2

35.0

8.30

35

156

972

oc

n

11/ 4/29

27.6

35.0

8.34

28

973

50

oc

n

11/ 4/29

27.0

35.1

8.37

46

157

978

c

n

11/ 6/29

27.1

35.3

8.27

47

979

50

c

n

11/ 6/29

27.1

35.2

8.32

60

980

100

r

n

11/ 6/29

26.8

35.5

8.30

64

158

984

50

r

n

11/ 8/29

28.2

35.6

8.39

50

985

100

r

n

11/ 8/29

27.6

35.9

8.39

48

159

990

r

n

11/11/29

28.6

35.7

8.37

15

991

50

r

n

11/11/29

28.5

35.7

8.39

15

992

100

r

n

11/11/29

28.0

35.7

8.37

23

Table 11. Distributional and environmental records for Peridinium pallidum Ostenfeld

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature
CC)

Salinity
(o/oo)

pH

PC.

34

:/m

mg/m

Atlantic

3

18

50

r

n 5/21/28

15.0

36.1

8.15

99

20

oc

n 5/21/28

15.5

36.1

8.15

99

6b

45

r

D 6/ 2/28

10.2

35.4

8.11

28

46

r

n 6/ 2/28

10.2

35.4

8.11

28

68 STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

Table 11. Distributional and environmental records for Peridinium pallidum Ostenfeld--Concluded

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature
(°C)

Salinity
(o/oo)

PH

mg/mJ

Atlantic

--Concluded

6e

52

r

n

7/ 8/28

10.2

35.4

8.11

28

6g

54

r

n

7/10/28

10.2

35.4

8.11

28

6h

55

oc

n

7/11/28

10.2

35.4

8.11

28

7

56

00

n

7/13/28

8.9

35.2

8.08

34

57

50

oc

n

7/13/28

8.2

35.2

8.03

47

58

100

c

n

7/13/28

8.1

35.2

8.04

57

8

60

50

oc

n

7/15/28

9.1

35.2

7.95

27

61

100

r

n

7/15/28

8.4

35.3

7.95

54

9

64

oc

n

7/28/28

11.2

35.1

8.08

20

65

50

oc

n

7/28/28

8.4

35.1

7.96

55

66

100

oc

n

7/28/28

7.6

35.1

7.98

56

10

68

r

n

7/30/28

10.9

34.9

8.08

28

69

50

r

n

7/30/28

10.0

34.9

8.04

39

11a

78

oc

n

8/ 2/28

9.1

34.2

8.08

27

12

79

r

n

8/ 5/28

8.4

33.6

8.10

27

80

50

oc

n

8/ 5/28

3.9

34.7

7.91

95

81

100

oc

n

8/ 5/28

3.4

34.9

7.89

82

82

oc

p

8/ 5/28

8.4

33.6

8.10

27

13

85

50

c

n

8/ 7/28

-1.6

33.4

7.87

59

86

100

oc

n

8/ 7/28

-1.2

33.6

7.87

60

14

95

50

r

n

8/ 9/28

15.0

35.1

8.18

16

16

103

r

p

8/13/28

25.9

36.2

8.24

8

104

50

r

p

8/13/28

24.4

36.4

8.25

8

17

111

r

n

8/15/28

26.2

36.6

8.29

9

Pacific

97

575

50

oc

n

4/28/29

28.0

35.4

8.16

21

576

100

r

n

4/28/29

27.6

35.6

8.15

25

577

oc

p

4/28/29

28.3

35.2

8.16

24

98

583

100

r

n

4/30/29

26.7

35.4

8.14

32

584

oc

P

4/30/29

27.0

35.3

8.16

24

101

604

50

oc

n

5/ 7/29

26.2

34.7

8.24

8

605

100

oc

n

5/ 7/29

25.2

35.1

8.23

8

102

609

oc

n

5/ 9/29

25.8

35.0

8.24

8

610

50

r

n

5/ 9/29

25.8

35.0

8.24

8

611

100

oc

n

5/ 9/29

25.6

35.0

8.23

8

612

r

p

5/ 9/29

25.6

35.0

8.23

8

113

682

100

oc

n

6/25/29

21.5

34.7

8.23

8

114

686

r

n

6/27/29

19.9

34.3

8.15

7

688

100

r

P

6/27/29

13.0

34.5

8.00

91

116

703

50

oc

n

7/ 1/29

10.6

33.8

8.11

23

706

50

r

p

7/ 1/29

10.6

33.8

8.11

23

117

711

r

p

7/ 3/29

15.9

34.3

8.17

3

709

50

oc

n

7/ 3/29

12.5

34.2

8.06

51

712

50

oc

p

7/ 3/29

12.5

34.2

8.06

51

710

100

oc

n

7/ 3/29

8.8

34.1

7.98

84

133

806

100

r

n

9/10/29

18.4

34.8

8.31

7

813

50

r

P

9/10/29

20.8

34.7

8.37

7

808

r

n

9/10/29

22.7

34.7

8.47

7

134

810

100

r

n

9/12/29

18.1

34.6

8.34

6

135

821

50

oc

n

9/14/29

21.5

35.0

8.37

5

136

828

50

r

n

9/16/29

21.4

35.1

8.39

3

833

50

r

P

9/16/29

21.4

35.1

8.39

3

834

100

oc

P

9/16/29

18.6

35.0

8.39

3

137

836

oc

n

9/16/29

25.5

35.0

8.39

4

Table 12. Distributional and environmental records for Ceratocorys horrida Stein

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature

rc)

Salinity
(o/oo)

pH

mg/m"»

Atl

antic

1

1

oc

n

5/12/28

24.0

36.2

8.16

34

2

70

r

n

5/12/28

22.1

36.5

8.17

39

la

4

r

4"n

5/14/28

(22.0)

(36.3)

(8.20)

(45)*

lb

7

50

c

n

5/16/28

22.0)

(36.3)

(8.20)

(45 *

8

100

oc

n

5/16/28

(22.0)

(36.3)

(8.20)

(45)*

2

13

100

r

n

5/18/28

19.8

36.4

8.21

33

14

oc

n

5/18/28

20.5

36.4

8.23

58

15

102

100

oc

n

8/11/28

18.4

36.4

8.20

19

16

103

r

P

8/13/28

25.9

36.2

8.24

8

104

50

r

P

8/13/28

24.4

36.4

8.23

8

106

oc

n

8/13/28

25.9

36.2

8.24

8

107

50

oc

n

8/13/28

24.4

36.4

8.23

8

DISTRIBUTIONAL AND ENVIRONMENTAL RECORDS

69

Table 12. Distributional and environmental records for

Ceratocorys horrida Stein- -Continued

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature

rc)

Salinity
(o/oo)

PH

mg/m"»

Atlant

c --Concluded

108

100

r

n

8/13/28

19.9

17

109

r

P

8/15/28

26.2

110

50

r

p

8/15/28

21.9

112

50

oc

n

8/15/28

21.9

113

100

00

n

8/15/28

19.3

19

122

r

n

8/20/28

26.6

20

128

oc

n

8/22/28

26.1

129

50

r

n

8/22/28

25.8

130

100

oc

n

8/22/28

22.6

21

132

r

P

8/25/28

26.6

134

100

r

P

8/25/28

21.0

135

oc

n

8/25/28

26.6

137

100

r

n

8/25/28

21.0

22

139

r

P

8/27/28

26.7

143

50

oc

n

8/27/28

24.5

23

145

r

P

8/29/28

27.2

148

r

n

8/29/28

27.2

149

50

oc

n

8/29/28

20.9

24

151

r

p

8/31/28

27.2

152

50

r

p

8/31/28

23.1

155

50

r

n

8/31/28

23.1

25

157

oc

P

9/ 3/28

27.5

158

50

r

p

9/ 3/28

21.5

161

50

oc

n

9/ 3/28

21.5

162

100

r

n

9/ 3/28

14.6

31

191

r

n

10/ 3/28

28.5

192

50

oc

n

10/ 3/28

28.2

193

100

oc

n

10/ 3/28

23.5

32

194

c

n

10/ 5/28

28.0

194a

oc

P

10/ 5/28

28.0

195

50

c

n

10/ 5/28

27.2

196

100

oc

n

10/ 5/28

22.2

33

197a

oc

P

10/ 8/28

28.5

198

50

r

n

10/ 8/28

28.2

198a

50

oc

p

10/ 8/28

28.2

34

200

oc

n

10/ 9/28

28.5

200a

oc

p

10/ 9/28

28.5

201

100

r

n

10/ 9/28

20.5

202

50

oc

n
P

10/ 9/28
acific

25.0

35

205

100

r

n

10/26/28

14.4

206

oc

p

10/26/28

27.4

35a

208

c

n

10/26/28

(27.0)

209

c

n

10/27/28

27.0)

211

oc

n

10/28/28

27.0

212

c

n

10/28/28

(27.0)

36

213

oc

n

10/20/28

26.5

216

r

P

10/20/28

26.5

37

217

oc

n

11/ 1/28

27.1

218

50

oc

n

11/ 1/28

19.8

219

100

oc

n

11/ 1/28

15.1

220

oc

P

11/ 1/28

27.1

38

222

r

n

11/ 3/28

26.5

39

226

50

r

n

11/ 6/28

16.3

227

100

r

n

11/ 6/28

14.0

41a

240

oc

n

11/12/28

(21.0)

42

241

r

n

11/13/28

18.7

243

100

r

n

11/13/28

13.6

44

250

r

n

11/17/28

20.7

45

256

oc

n

11/19/28

22.4

257

50

oc

n

11/19/28

22.4

258

100

r

n

11/19/28

18.6

259

r

P

11/19/28

22.4

260

50-0

r

P

11/19/28

22.4

261

oc

n

11/21/28

23.3

262

50

oc

n

11/21/28

23.2

263

100

r

n

11/21/28

22.6

264

r

P

11/21/28

23.3

47

266

r

n

11/23/28

23.9

267

50

oc

n

11/23/28

23.8

268

100

r

n

11/23/28

22.7

270

50

r

P

11/23/28

23.8

48

271

oc

n

11/25/28

23.6

272

50

oc

n

11/25/28

23.6

273

100

oc

n

11/25/28

22.7

36.5
36.6
36.6
36.6
36.5
37.0
36.6
36.6
36.7
36.3
36.8
36.3
36.8
36.0
36.2
35.9
35.9
36.0
35.2
36.0
36.0
35.6
36.0
36.0
35.7
34.4
35.4
36.5
36.0
36.0
35.9
36.4
35.6
36.2
36.2
35.9
35.9
36.6
36.5

34.9
29.7

(30.5)
30.5
30.5)
30.5)
31.6
31.6
31.7
34.5
34.9
31.7
32.9
34.6
35.0

(34.0)
34.7
35.0
34.9
35.3
35.2
35.1
35.3
35.3
35.3
35.3
35.4
35.3
36.0
36.0
36.2
36.0
36.4
36.4
36.3

8.17
8.29
8.28
8.28
8.23
8.34
8.37
8.26
8.19
8.32
8.25
8.32
8.25
8.26
8.21
8.25
8.25
8.27
8.32
8.28
8.28
8.31
8.30
8.30
8.22
8.27
8.25
8.22
8.23
8.23
8.24
8.20
8.23
8.24
8.24
8.28
8.28
8.16
8.21

7.88
8.31

(8.26)
8.26)
8.26

(8.26)
8.23
8.23
8.28
8.00
7.92
8.28
8.33
7.92
7.88

(8.15)
8.10
7.91
8.03
8.12
8.13
8.12
8.12
8.12
8.16
8.16
8.17
8,16
8.23
8.23
8.23
8.23
8.23
8.24
8.26

13
9

12

12
9
5
5
3
5
4
4
4
4
8
9
4
4
4
4
4
4
5
4
4

12
2
2
2
2
2
2
4
4
4
4
2
2

16
3

189

15
(16)*

16)*

16 *
(16)*

16

16

15
121
153

15

20

48
181

(28)*

45
150

38

38

46

46

38

38

36

40

40

36

17

20

20

20

13

16

16

70 STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

Table 12. Distributional and environmental records for Ceratocorys horrida Stein- -Continued

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature

Salinity
(o/oo)

PH

PO4,

mg/m3

Paoi

48

274

00

p

49

277

oc

n

278

50

00

n

279

100

00

n

281

50

r

p

4ga

283

00

n

50

284

oc

n

285

50

oc

n

288

50

r

p

50a

290

oc

n

291

00

n

292

oc

n

51

293

oc

n

294

50

oc

n

295

100

oc

n

52

299

r

n

300

50

oc

n

301

100

00

n

53

303

r

n

304

50

oc

n

305

100

c

n

306

oc

p

53a

307

00

n

308

oc

n

310

c

n

311

oc

n

312

oc

n

313

r

n

316

r

n

317

oc

n

54

320

50

00

n

321

100

00

n

322

00

p

55

323

r

n

324

50

oc

n

325

100

00

n

327

50

r

p

56

328

00

n

329

50

oc

n

330

100

r

n

331

r

p

332

50

r

p

333

100

r

p

56a

334

r

n

57

335

00

n

336

50

00

n

337

100

r

n

338

r

p

61a

369

r

n

75

462

r

n

465

r

p

76

467

c

n

469

100

r

n

470

r

p

77

472

00

n

473

r

p

474

50

oc

p

78

475

r

n

477

100

00

n

478

r

p

79

481

OC

n

482

r

n

483

100

oc

n

484

r

p

80

486

r

n

487

50

r

n

488

r

p

489

50

r

P

81

491

oc

n

492

50

r

n

495

100

r

p

82

496

00

n

497

50

r

n

83

501

oc

n

502

50

00

n

504

50

r

D

fie --Continued

11/25/28

11/27/28

11/27/28

11/27/28

11/27/28

11/28/28

11/29/28

11/29/28

11/29/28

11/30/28

11/30/28

11/30/28

12/ 1/28

12/ 1/28

12/ 1/28

12/ 3/28

12/ 3/28

12/ 3/28

12/ 5/28

12/ 5/28

12/ 5/28

12/ 5/28

12/ 6/28

12/ 6/28

12/10/28

12/10/28

12/10/28

12/10/28

12/12/28

12/12/28

12/14/28

12/14/28

12/14/28

12/16/28

12/16/28

12/16/28

12/16/28

12/18/28

12/18/28

12/18/28

12/18/28

12/18/28

12/18/28

12/19/28

12/20/28

12/20/28

12/20/28

12/20/28

12/28/28

2/14/29

2/14/29

2/16/29

2/16/29

2/16/29

2/18/29

2/18/29

2/18/29

2/20/29

2/20/29

2/20/29

2/22/29

2/22/29

2/22/29

2/22/29

2/24/29

2/24/29

2.24/29

2/24/29

2/26/29

2/26/29

2/26/29

2/28/29

2/28/29

3/ 2/29

3/ 2/29

3/ 2/29

23.6
23.4
22.6
21.6
22.6
(23.3)
23.2
22.0
22.0
(23.0)
(23.0
(23.0)
22.8
20.5
20.0
22.5
20.2
18.2
22.6
21.2
19.9
22.6
;23.0)
23.0)
23.0)
23.0
23.0
23.0)
23.0)
;23.0)
19.8
18.7
23.4
20.4
18.7
16.7
18.7
20.8
18.5
16.6
20.8
18.5
16.6
(20.0)
19.0
15.6
14.3
19.0
(17.5)
22.8
22.8

23.

21.

23.

23.

23.

23.

24.6

21.9

24.6

25.2

25.2

21.8

25.2

26.0

25.9

26.0

25.9

26.5

26.4

23.7

27.2

27.2

27.5

27.5

27.5

36.4
36.2
36.1
35.9
36.1

(36.1)
36.0
36.0
36.0

(35.8)

(35.8)

(35.8)
35.6
35.6
35.6
35.4
35.6
35.2
35.7
35.8
35.6
35.7

(35.6)
35.6)
35.6
35.6
35.6)
35.6)
35.6

(35.6)
35.4
35.4
35.5
34.9
35.0
34.9
35.0
34.9
35.1
34.8
34.9
35.1
34.8

(34.9)
34.5
34.3
34.4
34.5

(34.1)
35.8
35.8
35.9
35.8
35.9
36.0
36.0
36.0
36.0
36.2
36.0
36.0
36.0
36.2
36.0
35.9
36.0
35.9
36.0
35.8
35.9
36.2
36.3
36.3
36.3
36.5
36.5

(8-22) (
(8.22 (

8.23
8.27
8.26
8.26
8.26
(8.25)
8.23
8.23
8.23
8.22
8.22
(8.22
8.22
8.22
8.22
8.21
8.20
8.17
8.22
8.20
8.20
8.22
8.22
'8.22'
8.22
'8.22
8.22
8.22
8.22
Is. 22
8.18
8.16
8.22
8.19
8.18
7.17
8.18
8.13
8.14
8.11
8.13
8.14
8.11
(8.13)
8.14
8.14
8.13
8.14
(8.07)
8.18
8.18
8.15
8.12
8.15
8.19
8.19
8.19
8.2
8.1
8.2
8.17
8.17
8.13
8.17
8.20
8.19
8.20
8.19
8.19
8.19
8.18
8.21
8.21
8.24
8.24
8.24

13

13

13

13

13
(13)*

13

13

13

13)»

13*
(13)*

16

16

17
8
8
8

13

13

13

13
(11V

11)

11)
(11)

11)

llV

llV
(11>

17

20
9

12

12

12

12
9
9

12
9
9

12
(15;*

20

21

25

20
(39)*

44

44

50

50

50

16

16

16

32

34

32

34

34

45

34

36

29

36

29

38

38

36

34

34

29

25

25

DISTRIBUTIONAL AND ENVIRONMENTAL RECORDS

71

Table 12. Distributional and environmental records for Ceratocorys horrida Stein--Continued

Station

Sample

Depth

(m)

Relative
abundance

Apparatus

Date

Temperature

(°C)

Salinity
(o/oo)

pH

P°/4 3

mg/m^

Pacific

--Continued

84

505

r

n

3/ 4/29

27.8

36.2

8.23

24

506

50

r

n

3/ 4/29

27.5

36.4

8.21

24

85

510

r

n

3/ 6/29

27.9

36.2

8.22

40

511

50

r

n

3/ 6/29

27.9

36.2

8.22

40

86

515

oc

n

3/ 9/29

28.2

36.2

8.29

20

516

c

n

3/ 9/29

28.2

36.2

8.29

20

517

50

oc

n

3/ 9/29

27.5

36.2

8.29

17

518

r

p

3/ 9/29

28.2

36.2

8.29

20

87

521

c

n

3/11/29

27.9

36.1

8.28

17

522

50

oc

n

3/11/29

26.5

36.1

8.26

20

523

r

p

3/11/29

27.9

36.1

8.28

17

524

50

r

p

3/11/29

26.5

36.1

8.26

20

88

526

oc

n

3/21/29

28.5

35.9

8.23

16

527

50

oc

n

3/21/29

28.5

35.9

8.25

13

89

528

oc

n

3/23/29

28.4

35.6

8.25

21

529

50

r

n

3/23/29

28.6

35.8

8.27

12

530

r

p

3/23/29

28.4

35.6

8.25

21

532

oc

n

3/23/29

28.4

35.6

8.25

21

90

533

c

n

3/25/29

28.5

35.5

8.27

21

534

50

oc

n

3/25/29

28.6

35.6

8.26

21

91

540

oc

n

3/27/29

28.7

35.1

8.30

21

541

50

oc

n

3/27/29

28.5

35.2

8.30

24

542

r

P

3/27/29

28.7

35.1

8.30

21

544

100

r

P

3/27/29

25.8

36.0

8.25

30

92

545

c

n

3/29/29

28.5

35.3

8.29

28

546

50

oc

n

3/29/29

28.4

35.4

8.29

28

93

550

c

n

3/31/29

28.7

34.7

8.30

28

551

50

oc

n

3/31/29

28.5

34.8

8.30

28

552

r

p

3/31/29

28.7

34.7

8.30

28

553

100

r

p

3/31/29

27.6

35.9

8.27

29

94

557

r

n

4/22/29

29.5

34.7

8.25

14

558

50

oc

n

4/22/29

29.3

34.7

8.25

14

559

100

r

n

4/22/29

28.5

35.6

8.21

25

95

563

50

c

n

4/25/29

29.3

34.9

8.24

16

564

100

oc

n

4/25/29

28.5

35.4

8.22

21

565

r

p

4/25/29

29.4

34.7

8.26

14

567

100

r

p

4/25/29

28.5

35.4

8.22

21

568a

r

n

4/25/29

28.5

35.4

8.26

21

96

568

oc

n

4/26/29

29.3

35.3

8.23

12

569

50

oc

n

4/26/29

29.2

35.3

8.23

12

570

100

oc

n

4/26/29

28.3

35.7

8.19

25

572

50

r

p

4/26/29

29.2

35.3

8.23

12

97

574

c

n

4/28/29

28.3

35.2

8.16

24

575

50

c

n

4/28/29

28.0

35.4

8.16

21

576

100

r

n

4/28/29

27.6

35.6

8.15

25

578

50

r

p

4/28/29

28.0

35.4

8.16

21

99

589

oc

n

5/ 2/29

27.9

34.9

8.21

12

590

50

oc

n

5/ 2/29

27.9

34.9

8.22

12

591

100

oc

n

5/ 2/29

27.8

35.0

8.22

17

595

r

n

5/ 2/29

27.9

34.9

8.21

12

100

596

50

c

n

5/ 4/29

27.6

34.7

8.21

10

597

100

r

n

5/ 4/29

27.6

34.7

8.22

12

599

50

oc

p

5/ 4/29

27.6

34.7

8.21

10

101

603

c

n

5/ 7/29

26.3

34.7

8.24

8

604

50

c

n

5/ 7/29

26.2

34.7

8.24

8

605

100

c

n

5/ 7/29

25.2

35.1

8.23

8

607

50

r

P

5/ 7/29

26.2

34.7

8.24

8

608

100

r

P

5/ 7/29

25.2

35.1

8.23

8

102

609

oc

n

5/ 9/29

25.8

35.0

8.24

8

610

50

oc

n

5/ 9/29

25.8

35.0

8.24

8

611

100

oc

n

5/ 9/29

25.6

35.0

8.23

8

103

615

c

n

5/11/29

26.0

35.0

8.25

5

616

50

c

n

5/11/29

25.8

35.2

8.25

5

617

100

oc

n

5/11/29

24.8

35.2

8.25

5

620

100

r

P

5/11/29

24.8

35.2

8.25

5

104

621

c

n

5/13/29

26.1

35.2

8.24

7

622

50

c

n

5/13/29

25.8

35.2

8.24

7

623

100

c

n

5/13/29

25.3

35.3

8.21

7

624

oc

p

5/13/29

26.1

35.2

8.24

7

105

627

50

c

n

5/15/29

26.8

34.9

8.23

5

628

50

c

n

5/15/29

26.8

34.9

8.23

5

629

100

c

n

5/15/29

25.2

35.1

8.23

5

630

r

p

5/15/29

26.9

34.9

8.23

5

106

633

oc

n

5/17/29

27.2

35.0

8.23

5

634

50

oc

n

5/17/29

27.0

35.0

8.23

5

635

100

oc

n

5/17/29

25.6

35.1

8.23

5

72 STtFDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

Table 12. Distributional and environmental records for Ceratocorys horrida Stein--Continued

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature
(°C)

Salinity
(o/oo)

PH

mg/m"*

Pacific

--Continued

107

639

c

n

5/19/29

28.0

34.4

8.23

5

640

50

DC

n

5/19/29

27.9

34.4

8.23

4

108

646

C

n

5/27/29

28.4

35.0

8.25

4

647

50

oc

n

5/27/29

26.8

35.0

8.24

4

648

100

c

n

5/27/29

25.2

35.0

8.23

4

Guam

652

r

n

May 1929
5/29/29

109

654

c

n

27.4

35.0

8.23

3

655

50

00

n

5/29/29

23.1

35.0

8.22

3

656

100

oc

n

5/29/29

19.4

34.8

8.18

5

658

50

00

p

5/29/29

23.1

35.0

8.22

3

659

100

oc

p

5/29/29

19.4

34.8

8.18

5

660

oc

P

5/29/29

27.4

35.0

8.23

3

110

661

00

n

5/31/29

23.9

34.7

8.18

5

662

50

oc

n

5/31/29

18.4

34.8

8.16

5

663

100

r

n

5/31/29

17.9

34.7

8.14

11

111

668

r

n

6/ 3/29

20.1

34.5

8.18

5

672

50

r

P

6/ 3/29

19.4

34.6

8.17

5

112

674

r

n

6/ 5/29

23.2

34.6

8.22

7

675

50

r

n

6/ 5/29

21.7

34.6

8.23

7

676

100

r

n

6/ 5/29

19.8

34.7

8.20

8

113

680

oc

n

6/25/29

24.2

34.5

8.25

5

681

50

r

n

6/25/29

23.8

34.6

8.25

5

682

100

r

n

6/25/29

21.5

34.7

8.23

8

685

100

r

P

6/25/29

21.5

34.7

8.23

8

131

787

r

n

9/ 6/29

19.3

33.4

8.34

789

100

r

n

9/ 6/29

12.1

33.4

8.32

132

797

oc

n

9/ 8/29

21.0

33.9

8.34

15

798

50

GO

n

9/ 8/29

17.6

33.9

8.33

19

799

100

oc

n

9/ 8/29

14.3

33.4

8.30

16

802

50

r

P

9/ 8/29

17.6

33.9

8.33

19

803

100

r

P

9/ 8/29

14.3

33.4

8.30

16

133

804

oc

n

9/10/29

22.7

34.7

8.47

7

805

50

r

n

9/10/29

20.8

34.7

8.37

7

806

100

oc

n

9/10/29

18.4

34.8

8.31

7

813

50

r

P

9/10/29

20.8

34.7

8.37

7

814

100

r

P

9/10/29

18.4

34.8

8.31

7

134

808

00

n

9/12/29

22.9

34.7

8.34

6

809

50

oc

n

9/12/29

19.8

34.6

8.34

6

810

100

r

n

9/12/29

18.1

34.6

8.34

6

815

r

P

9/12/29

22.9

34.7

8.34

6

816

50

r

P

9/12/29

19.8

34.6

8.34

6

817

100

r

P

9/12/29

18.1

34.6

8.34

6

135

820

r

n

9/14/29

23.8

35.1

8.37

7

821

50

r

n

9/14/29

21.5

35.0

8.4

5

822

100

r

n

9/14/29

18.7

34.8

8.37

5

136

827

oc

n

9/16/29

24.6

35.4

8.37

3

828

50

oc

n

9/16/29

21.4

35.1

8.39

3

829

100

oc

n

9/16/29

18.6

35.0

8.39

3

832

r

P

9/16/29

24.6

35.4

8.37

3

834

100

r

P

9/16/29

18.6

35.0

8.39

3

137

836

c

n

9/18/29

25.5

35.0

8.39

4

838

100

r

n

9/18/29

21.5

35.1

8.30

5

138

843

00

n

9/20/29

26.1

34.8

8.35

5

844

50

00

n

9/20/29

25.6

34.7

8.30

3

847

r

P

9/20/29

26.1

34.8

8.35

5

139

849

r

n

9/22/29

26.7

34.8

8.34

6

850

50

oc

n

9/22/29

25.8

34.9

8.31

6

851

100

oc

n

9/22/29

22.4

35.2

8.28

6

853

r

p

9/22/29

26.1

34.9

8.4

5

854

50

r

P

9/22/29

25.8

34.9

8.3

6

140

856

00

n

10/ 3/29

26.9

35.0

8.42

7

857

50

oc

n

10/ 3/29

26.9

35.0

8.39

7

858

858

100

oc

n

10/ 3/29

25.5

35.0

8.34

7

860

r

P

10/ 3/29

26.9

35.0

8.42

7

141

864

.

c

n

10/ 5/29

25.9

35.2

8.34

5

865

50

c

n

10/ 5/29

24.8

35.3

8.34

5

868

r

P

10/ 5/29

26.9

35.2

8.34

5

869

50

r

P

10/ 5/29

24.8

35.3

8.34

5

870

50

r

P

10/ 5/29

24.8

35.3

8.34

5

142

872

n

10/ 7/29

24.1

34.8

8.33

5

873

50

00

n

10/ 7/29

21.8

34.8

8.30

5

874

100

c

n

10/ 7/29

16.6

34.4

8.27

7

876

r

P

10/ 7/29

24.1

34.8

8.33

5

877

50

r

P

10/ 7/29

21.8

34.8

8.30

5

879

100

r

P

10/ 7/29

16.6

34.4

8.27

7

143

883

100

r

n

10/ 9/29

13.8

34.1

8.30

10

DISTRIBUTIONAL AND ENVIRONMENTAL RECORDS

73

Table 12. Distributional and environmental records for Ceratocorys horrida Stein- -Concluded

Station

Sample

Depth

(ra)

Relative
abundance

Apparatus

Date

Temperature

(°C)

Salinity
(o/oo)

pH

''"As

mg/m-'

Pacific

--Concluded

144

886

oc

n

10/11/29

23.3

35.0

8.37

6

145

890

oc

n

10/13/29

22.3

34.6

8.29

6

891

50

00

n

10/13/29

18.7

34.3

8.34

6

892

100

oc

n

10/13/29

16.0

34.1

8.31

6

146

896

oc

n

10/15/29

22.4

34.9

8.37

6

897

50

oc

n

10/15/29

22.4

34.9

8.30

6

898

100

oc

n

10/15/29

19.7

34.3

8.26

7

147

904

50

r

n

10/17/29

23.1

35.3

8.29

5

905

100

oc

n

10/17/29

19.2

35.0

8.29

5

148

910

oc

n

10/19/29

23.4

35.2

912

100

r

n

10/19/29

20.0

35.0

149

920

oc

n

10/21/29

23.5

35.0

8.34

' 6

921

50

oc

n

10/21/29

23.3

35.0

8.37

6

922

100

oc

n

10/21/29

20.3

34.9

8.38

6

150

929

oc

n

10/23/29

25.6

34.7

8.39

7

930

50

oc

n

10/23/29

22.8

34.8

8.35

10

931

100

r

n

10/23/29

19.6

34.6

8.32

11

936

100

r

p

10/23/29

19.6

34.6

8.32

11

151

937

r

n

10/25/29

26.0

34.0

938

50

r

n

10/25/29

18.3

34.4

939

100

r

n

10/25/29

12.5

34.6

152

944

r

n

10/27/29

27.4

33.7

8.35

20

946

100

r

n

10/27/29

11.4

34.7

7.76

75

153

951

oc

n

10/29/29

28.1

34.2

8.47

7

952

50

oc

n

10/29/29

28.1

34.4

8.39

7

953

100

r

n

10/29/29

20.5

34.7

8.28

31

955

r

p

10/29/29

28.1

34.2

8.47

7

154

958

oc

n

10/31/29

28.3

34.2

8.39

7

959

50

oc

n

10/31/29

28.2

34.2

8.40

7

155

965

c

n

11/ 2/29

27.8

34.9

8.29

29

966

50

oc

n

11/ 2/29

27.7

34.9

8.30

30

967

100

oc

n

11/ 2/29

27.2

35.0

8.30

35

156

972

oc

n

11/ 4/29

27.6

35.0

8.34

28

973

50

r

n

11/ 4/29

27.0

35.1

8.37

46

974

100

oc

n

il/ 4/29

26.4

35.1

8.30

48

157

978

c

n

11/ 6/29

27.1

35.3

8.27

47

979

50

c

n

11/ 6/29

27.1

35.2

8.32

60

980

100

oc

n

11/ 6/29

26.9

35.5

8.30

64

158

983

c

n

11/ 8/29

28.2

35.6

8.34

36

984

50

c

n

11/ 8/29

28.2

35.6

8.39

50

985

100

c

n

11/ 8/29

27.6

35.9

8.39

48

159

990

oc

n

11/11/29

28.6

35.7

8.37

15

991

50

oc

n

11/11/29

28.5

35.7

8.39

15

992

100

r

n

11/11/29

28.0

35.7

8.37

23

160

1000

r

n

11/13/29

28.6

35.6

8.37

12

1002

50

r

n

11/13/29

28.6

35.6

8.39

15

Table 13. Distributional and environmental records lor Ceratocorys armata (Schutt) Kofoid

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature

(°C)

Salinity
(o/oo)

pH

^94 3
mg/m"'

AtlE

inti c

2

13

100

r

n

5/18/28

19.8

36.4

8.21

33

14

r

n

5/18/28

20.5

36.4

8.23

58

15

99

100

r

p

8/11/28

18.4

36.4

8.20

19

16

103

r

p

8/13/28

25.9

36.2

8.24

8

104

50

r

p

8/13/28

24.4

36.4

8.23

8

106

oc

n

8/13/28

25.9

36.2

8.24

8

18

114

r

p

8/17/28

27.0

37.0

8.23

5

115

50

r

p

8/17/28

22.4

36.8

8.24

5

117

c

n

8/17/28

27.0

37.0

8.23

5

118

50

r

n

8/17/28

22.4

36.8

8.24

5

119

100

oc

n

8/17/28

20.4

36.8

8.24

5

21

134

100

oc

p

8/25/28

21.0

36.8

8.25

4

135

oc

n

8/25/28

26.6

36.3

8.32

4

22

139

r

p

8/27/28

26.7

36.0

8.26

8

140

50

r

p

8/27/28

24.5

36.2

8.21

9

24

151

r

P

8/31/28

27.2

35.2

8.32

4

25

157

r

P

9/ 3/28

27.5

35.6

8.31

5

28

178

100

r

n

9/11/28

22.8

36.6

8.23

4

29

184

100

r

n

9/13/28

23.1

36.6

8.26

8

31

191

r

n

10/ 3/28

28.5

34.4

8.27

2

34

200

r

n

10/ 9/28

28.5

35.9

8.28

2

200a

oc

P

10/ 9/28

28.5

35.9

8.28

-2

74 STUDIES IN THE MORPHOLOGY. TAXONOMY, AND ECOLOGY OF THE PEfUDINIALES

Table 13. Distributional and environmental records for Ceratocorys armata (Schiitt) Kofoid- -Continued

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature

(°C)

Salinity
(o/oo)

PH

PO4

mg/m^

p

acif ic

35a

209

r

n

10/27/28

(27.0)

(30.0)

(8.26)

(15)*

36

213

r

n

10/20/28

26.5

31.6

8.23

16

215

100

r

n

10/20/28

14.4

34.9

7.8

149

41

237

100

r

n

11/10/28

14.5

35.0

7.92

151

238

r

p

11/10/28

20.4

34.2

8.11

32

239

100

r

p

11/10/28

14.5

35.0

7.92

151

48

272

50

oc

n

11/25/28

23.6

36.4

8.24

16

273

100

oc

n

11/25/28

22.7

36.3

8.26

16

274

r

p

11/25/28

23.6

36.4

8.23

13

275

50

r

p

11/25/28

23.6

36.4

8.24

16

49

277

oc

n

11/27/28

23.4

36.2

8.27

13

279

100

oc

n

11/27/28

21.6

35.9

8.26

13

280

r

p

11/27/28

23.4

36.2

8.27

13

4ga

283

oc

n

11/28/28

(23.3)

(36.1)

(8.25)

(13)*

50

284

c

n

11/29/28

23.2

36.0

8.23

13

285

50

oc

n

11/29/28

22.0

36.0

8.23

13

286

100

oc

n

11/29/28

20.5

35.7

8.22

13

287

oc

p

11/29/28

23.2

36.0

8.23

13

50a

290

oc

n

11/30/28

(23.0)

(35.8)

(8.22)

(13)*

291

oc

n

11/30/28

(23.0

(35.8

(8.22)

(13)*

292

oc

n

11/30/28

(23.0)

(35.8)

(8.22)

(13)*

51

294

50

oc

n

12/ 1/28

20.5

35.6

8.22

16

295

100

oc

n

12/ 1/28

20.0

35.6

8.22

17

296

r

p

12/ 1/28

22.8

35.6

8.22

16

52

300

50

oc

n

12/ 3/28

20.2

35.6

8.20

8

301

100

oc

n

12/ 3/28

18.2

35.2

8.17

8

302

oc

p

12/ 3/28

22.5

35.4

8.21

8

53

304

50

c

n

12/ 5/28

21.2

35.8

8.20

13

305

100

oc

n

12/ 5/28

19.9

35.6

8.20

13

306

r

P

12/ 5/28

22.6

35.7

8.22

13

53a

308

r

n

12/ 6/28

(23.0)

(35.6)

(8.22)

(11)*

310

c

n

12/10/28

23.0

(35.6

8.22)

(11)*

311

oc

n

12/10/28

(23.0)

(35.6

8.22

(11 *

312

oc

n

12/10/28

(23.0

(35.6)

(8.22

U*
(11*

313

oc

n

12/10/28

(23.0

(35.6

(8.22

316

r

n

12/12/28

(23.0)

(35.6

8.22)
(8.22)

(11*

317

oc

n

12/12/28

(23.0)

(35.6)

(11)*

54

320

50

r

n

12/14/28

19.8

35.4

8.18

17

322

oc

p

12/14/28

23.4

35.5

8.22

9

55

323

r

n

12/16/28

20.4

34.9

8.19

12

324

50

oc

n

12/16/28

18.7

35.0

8.18

12

325

50

oc

n

12/16/28

18.7

35.0

8.18

12

56

328

oc

n

12/18/28

20.8

34.9

8.13

9

329

50

oc

n

12/18/28

18.5

35.1

8.14

9

330

100

oc

n

12/18/28

16.6

34.8

8.11

12

331

oc

P

12/18/28

20.8

34.9

8.13

9

332

50

r

P

12/18/28

18.5

35.1

8.14

9

56a

334

oc

n

12/19/28

(20.0)

(34.9)

(8.13)

(15)*

57

336

50

oc

n

12/20/28

15.6

34.3

8.14

21

338

r

P

12/20/28

19.0

34.5

8.14

20

339

50

r

p

12/20/28

15.6

34.3

8.14

21

340

100

r

p

12/20/28

14.3

34.4

8.13

25

62

373

100

r

n

12/30/28

13.2

34.2

8.06

48

63

380

50

r

n

1/ 1/29

17.0

34.6

8.08

25

38"2

r

p

1/ 1/29

20.5

34.6

8.07

21

64a

401

r

n

1/ 3/29

(20.4)

(34.6)

(8.11)

(22)*

78

478

r

p

2/20/29

24.6

36.0

8.17

32

83

503

r

p

3/ 2/29

27.5

36.3

8.24

29

84

506

50

r

n

3/ 4/29

27.5

36.4

8.21

24

85

510

r

n

3/ 6/29

28.0

36.3

8.22

40

86

515

r

n

3/ 9/29

28.2

36.2

8.29

20

516

oc

n

3/ 9/29

28.2

36.2

8.29

20

517

50

r

n

3/ 9/29

27.5

36.2

8.29

17

518

r

p

3/ 9/29

28.2

36.2

8.29

20

87

521

r

n

3/11/29

27.9

36.1

8.28

17

88

526

oc

n

3/21/29

28.5

35.9

8.23

16

89

528

r

n

3/23/29

28.4

35.6

8.25

21

532

r

n

3/23/29

28.4

35.6

8.25

21

90

533

oc

n

3/25/29

28.5

35.5

8.27

21

534

50

oc

n

3/25/29

28.6

35.6

8.26

21

535

r

P

3/25/29

28.5

35.5

8.27

21

91

540

oc

n

3/27/29

28.7

35.1

8.30

21

541

50

oc

n

3/27/29

28.5

35.2

8.30

24

542

r

p

3/27/29

28.7

35.1

8.30

21

92

545

oc

n

3/29/29

28.5

35.3

8.29

28

93

550

r

n

3/31/29

28.7

34.7

8.30

28

551

50

oc

n

3/31/29

28.5

34.8

8.30

28

DISTRIBUTIONAL AND ENVIRONMENTAL RECORDS

75

Table 13. Distributional and environmental records forCeratocorys armata (Schutt) Kofoid- -Concluded

Station

Sample

Depth

(m)

Relative
abundance

Apparatus

Date

Temperature

Salinity
(o/oo)

PH

mg/m'i

Pacific

--Concluded

95

568a

r

n

4/24/29

29.4

34.7

8.26

14

99

595

r

n

5/ 2/29

27.9

34.9

8.21

12

101

603

c

n

5/ 7/29

26.3

34.7

8.24

8

604

50

c

n

5/ 7/29

26.3

34.7

8.24

8

605

100

c

n

5/ 7/29

25.3

35.1

8.23

8

608

100

r

P

5/ 7/29

25.3

35.1

8.23

8

102

609

r

n

5/ 9/29

25.8

35.0

8.24

8

610

50

oc

n

5/ 9/29

25.8

35.0

8.24

8

611

100

oc

n

5/ 9/29

25.6

35.0

8.23

8

612

r

p

5/ 9/29

25.8

35.0

8.24

8

613

50

r

P

5/ 9/29

25.8

35.0

8.24

8

103

615

c

n

5/11/29

26.0

35.0

8.25

5

616

50

oc

n

5/11/29

25.9

35.2

8.25

5

617

100

r

n

5/11/29

24.8

35.2

8.25

5

620

100

r

p

5/11/29

24.8

35.2

8.25

5

104

621

c

n

5/13/29

26.1

35.2

8.24

7

622

50

oc

n

5/13/29

25.9

35.2

. . .

623

100

oc

n

5/13/29

26.3

35.3

8. '21

7

624

r

p

5/13/29

26.1

35.2

8.24

7

105

627

50

c

n

5/13/29

25.9

35.2

8.24

7

629

100

oc

n

5/13/29

26.3

35.3

8.21

7

106

633

oc

n

5/17/29

27.2

35.0

8.23

5

634

50

oc

n

5/17/29

27.0

35.0

635

100

oc

n

5/17/29

25.6

35.1

8.23

' '5'

107

639

oc

n

5/19/29

28.0

34.4

8.23

5

641

100

r

n

5/19/29

26.8

34.9

8.23

5

109

654

oc

n

5/29/29

27.4

35.0

8.23

3

655

50

r

n

5/29/29

23.1

35.0

658

50

r

p

5/29/29

23.1

35.0

660

r

p

5/29/29

27.4

35.0

8.23

' "3

110

661

r

n

5/31/29

23.9

34.7

8.18

5

113

680

r

n

6/25/29

24.2

34.5

8.25

5

134

810

100

r

n

9/12/29

18.1

34.6

8.34

6

135

818

r

n

9/14/29

23.8

35.1

8.37

7

824

r

p

9/14/29

23.8

35.1

8.37

7

136

827

r

n

9/16/29

24.6

35.4

8.37

3

829

100

r

n

9/16/29

18.7

35.0

8.39

3

832

r

p

9/16/29

24.6

35.4

8.37

3

137

836

r

n

9/18/29

25.5

35.0

8.39

4

838

100

r

n

9/18/29

21.5

35.1

8.30

5

840

r

p

9/18/29

25.5

35.0

8.39

4

842

100

r

P

9/18/29

21.5

35.1

8.30

5

138

844

50

r

n

9/20/29

25.6

34.7

8.30

3

845

100

r

n

9/20/29

22.2

34.8

8.31

3

139

850

50

r

n

9/22/29

25.8

34.9

8.31

6

141

864

r

n

10/ 5/29

25.9

35.2

8.34

5

870

50

r

p

10/ 5/29

24.8

35.3

8.34

5

142

872

r

n

10/ 7/29

24.1

34.9

8.33

5

873

50

r

n

10/ 7/29

21.8

34.8

8.30

5

874

100

r

n

10/ 7 29

16.6

34.5

8.27

7

144

886

r

n

10/11/29

23.27

35.0

8.37

6

887

r

p

10/11/29

23.27

35.0

8.37

6

145

890

oc

n

10/13/29

22.3

34.6

8.29

6

891

50

oc

n

10/13/29

18.7

34.3

8.34

6

892

100

r

n

10/13/29

16.0

34.1

8.31

6

893

r

P

10/13/29

22.3

34.6

8.29

6

146

896

r

n

10/15/29

22.4

34.9

8.37

6

149

921

50

r

n

10/21/29

23.3

35.0

8.36

6

922

100

r

n

10/21/29

20.3

34.9

8.36

6

927

r

P

10/21/29

23.5

35.0

8.34

6

928

50

r

n

10/21/29

23.3

35.0

8.36

6

150

930

50

oc

n

10/23/29

22.9

34.8

8.34

10

931

100

r

n

10/23/29

19.6

34.6

8.32

11

154

959

50

r

n

10/31/29

28.2

34.2

8.40

7

76 STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

Table 14. Distributional and environmental records for Ceratocorys reticulata n.sp.

Station

Sample

Depth

(m)

Relative
abundance

Apparatus

Date

Temperature

("C)

Salinity
(o/oo)

PH

mg/m-'

Atl

antic

28

177

50

r

n

9/11/28

26.7

36.3

8.26

4

Pacific

35b

211

r

n

10/28/28

(27.0)

(30.0)

(8.27)

(15)*

41

235

r

n

11/10/28

20.4

34.2

8.11

32

41a

240

'0

r

n

11/12/28

(19.5)

(34.4)

(8.09)

(38)»

76

468

50

r

n

2/16/29

22.1

35.9

8.14

42

78

478

r

P

2/20/29

24.6

36.0

8.17

32

89

529

50

r

n

3/23/29

28.6

35.8

8.27

12

90

533

DC

n

3/25/29

28.5

35.5

8.27

21

534

50

r

n

3/25/29

28.6

35.6

8.26

21

91

541

50

r

n

3/27/29

28.5

35.2

8.C0

24

92

546

50

r

n

3/29/29

28.4

35.4

8.29

28

94

558

50

r

n

4/22/29

29.3

34.7

8.25

14

95

564

100

r

n

4/24/29

28.5

35.4

8.22

?-l

96

570

100

r

n

4/26/29

28.3

35.7

8.19

25

100

597

100

r

n

5/ 4/29

27.6

34.7

8.22

12

101

604

50

oc

n

5/ 7/29

26.3

34.7

8.24

8

605

100

oc

n

5/ 7/29

25.3

35.1

8.23

8

607

50

r

P

5/ 7/29

26.3

34.7

8.24

8

102

609

r

n

5/ 9/29

25.8

35.0

8.24

8

610

50

oc

n

5/ 9/29

25.8

35.0

8.24

8

611

100

r

n

5/ 9/29

25.6

35.0

8.23

8

104

623

100

r

n

5/13/29

25.3

35.3

8.21

7

106

635

100

r

n

5/17/29

25.6

35.1

8.23

5

137

837

50

r

n

9/18/29

24.5

35.1

8.34

4

842

100

r

P

9/18/29

21.5

35.1

8.30

5

138

844

50

r

n

9/20/29

25.6

34.7

8.30

3

139

850

50

oc

n

9/22/29

25.8

34.9

8.31

6

851

100

r

n

9/22/29

22.4

35.2

8.28

6

140

856

r

n

10/ 3/29

26.9

35.0

8.42

7

857

50

r

n

10/ 3/29

26.9

35.0

8.39

7

858

100

r

n

10/ 3/29

25.5

35.2

8.34

7

141

865

50

r

n

10/ 5/29

24.8

35.3

8.34

5

153

952

50

r

n

10/29/29

28.1

34.4

8.39

7

953

100

r

n

10/29/29

20.5

34.7

8.28

31

154

958

r

n

10/31/29

28.3

34.2

8.39

7

156

973

50

r

P

11/ 4/29

27.0

35.1

8.37

46

157

979

50

r

n

11/ 6/29

27.1

35.2

8.32

60

158

983

r

n

11/ 8/29

28.2

35.6

8.34

36

985

100

r

n

11/ 8/29

27.7

35.9

8.39

48

159

991

50

r

n

11/11/29

28.5

35.7

8.38

19

160

1002

50

r

n

11/13/29

28.6

35.6

8.39

14

Table 15. Distributional and environmental records for Ceratocorys aultii n.sp.

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature

(°C)

Salinity
(o/oo)

pH

PO4

mg/m3

Pa

cif i c

57

337

100

r

n 1

2/20/28

14.3

34.4

8.10

40

62

371

r

n ]

2/30/28

16.9

34.0

8.05

46

65

406

50

r

n

1/ 5/29

16.5

34.5

8.10

25

408

r

P

1/ 5/29

20.2

34.5

8.10

24

409

50

r

P

1/ 5/29

16.5

34.5

8.10

25

83

501

r

n

3/ 2/29

27.5

36.3

8.24

29

503

r

p

3/ 2/29

27.5

36.3

8.24

29

92

549

100

r

p

3/29/29

26.2

36.0

8.28

28

93

551

50

r

n

3/31/29

28.5

34.8

8.30

28

94

558

50

r

n

4/22/29

29.3

34.7

8.25

14

559

100

r

n

4/22/29

28.5

35.6

8.21

25

95

564

100

r

n

4/24/29

28.5

35.4

8.22

21

104

623

100

r

n

5/13/29

25.3

35.3

8.21

7

105

629

100

r

n

5/15/29

25.2

35.1

8.23

5

107

640

50

r

n

5/19/29

27.9

34.4

8.23

4

642

r

P

5/19/29

28.0

34.4

8.23

5

132

803

100

r

P

9/ 8/29

14.3

33.4

8.30

16

133

814

100

r

P

9/10/29

18.4

34.8

8.31

7

136

828

50

r

n

9/16/29

21.4

35.1

8.39

3

829

100

r

n

9/16/29

18.6

35.0

8.39

3

146

898

100

r

n 1

0/15/29

19.7

34.3

8.26

7

DISTRIBUTIONAL AND ENVIRONMENTAL RECORDS

77

Table 16. Distributional and environmental records for Ceratocorys bipes (Cleve) Kofoid

Station

Sample

Depth

(m)

Relative
abundance

Apparatus

Date

Temperature

rc)

Salinity
(o/oo)

pH

mg/m3

Atl

antic

2

14

r

n

5/18/28

25.7

36.4

8.23

58

Pacific

45

257

50

r

n

11/19/28

22.4

35.2

8.13

46

258

100

r

n

11/19/28

18. e

35.1

8.12

46

260

50-0

r

11/19/28

46

261

r

n

11/21/28

23.3

35.3

8.16

36

262

50

r

n

11/21/28

23.2

35.3

8.16

40

265

50

r

p

11/21/28

23.2

35.3

8.16

40

47

268

100

r

n

11/23/28

22.7

36.2

8.23

20

48

273

100

r

n

11/25/28

22.7

36.3

8.26

16

276

100

r

P

11/25/28

22.7

36.3

8.26

16

52

301

100

r

n

12/ 3/28

18.2

35.2

8.17

8

53

305

100

r

n

12/ 5/28

19.9

35.6

8.20

13

56

330

100

r

n

12/18/28

16.6

34.8

8.11

12

77

474

50

oc

p

2/18/29

23.5

36.0

8.19

16

79

483

100

r

n

2/22/29

21.8

36.2

8.13

45

95

563

50

r

n

4/24/29

29.3

35

8.24

16

98

582

50

r

n

4/30/29

26.9

35.3

8.16

28

583

100

r

n

4/30/29

26.7

35.4

8.14

32

584

r

p

4/30/29

27.0

35.3

8.16

24

100

597

100

r

n

5/ 4/29

27.6

34.7

8.22

12

602

100

r

p

5/ 4/29

27.6

34.7

8.22

12

101

605

100

r

n

5/ 7/29

25.3

35.0

8.23

8

109

656
659

100
100

oc

r

n
p

5/29/29

19.5

34.8

8.18

5

112

676

100

r

n

6/ 5/29

19.9

34.7

8.20

8

137

841

50

r

P

9/18/29

24.5

35.1

8.34

4

140

863

100

r

P

10/ 3/29

25.5

35.0

8.34

7

151

938

50

r

n

10/25/29

18.3

34.4

. . .

154

960

100

r

n

10/31/29

25.3

34.8

7.93

21

156

973

50

r

p

11/ 4/29

27.0

35.1

8.37

46

974

100

r

n

11/ 4/29

26.4

35.1

8.30

48

157

979

50

r

n

11/ 6/29

27.1

35.2

8.32

60

Table 17.

Distributional and environmental records for Ceratocorys sko^sbergii n

-sp.

Station

Sample

Depth

(m)

Relative
abundance

Apparatus

Date

Temperature

(°C)

Salinity
(o/oo)

pH

PO4

mg/m3

Pa

cif i c

49a

283

r

n

11/28/28

(23.2)

(36.0)

(8.23)

(13)*

50a

291

r

n

11/30/28

(22.8)

35.6

(8.22

(16 *

53a

317

r

n

12/12/28

(23.0)

(35.6)

(8.22)

(11)*

85

513

50

r

p

3/ 6/29

27.8

36.2

8.22

40

89

529

50

r

n

3/23/29

28.6

35.8

8.27

12

91

540

r

n

3/27/29

28.7

35.1

8.30

21

542

r

p

3/27/29

28.7

35.1

8.30

21

100

597

100

r

n

5/ 4/29

27.6

34.7

8.22

12

102

610

50

r

n

5/ 9/29

25.8

35.0

8.24

8

113

682

100

r

n

6/25/29

21.5

34.7

8.23

8

160

1002

50

r

n

11/13/29

28.6

35.6

8.39

15

Table 18. Distributional and environmental records for Ceratocorys gourret

li Paulsen

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature

("C)

Salinity
(0/00)

pH

mg/m-'

16

103

23

145

25

157

26

163

29

179

181

100

45

256

257

50

r

oc

oc

r
r
r

Atlantic
8/13/28
8/29/28
9/ 3/28
9/ 5/28
9/13/28
9/13/28

Pacific
n 11/19/28

n 11/19/28

25.9
27.2
27.5
27.6
27.6
23.1

22.4
22.4

36.2

8.24

8

35.9

8.25

4

35.6

8.31

5

36.0

8.30

5

36.2

8.31

3

36.6

8.26

8

35.3

8.12

38

35.2

8.13

46

8 (frag-
ment)

78 STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

Table 18. Distributional and environmental records for Ceratocorys gourretii Paulsen- -Concluded

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature

- (°C)

Salinity
(o/oo)

PH

PO4,

mg/m^

Pacific

--Concluded

258

100

oc

n

11/19/28

18.6

35.1

8.12

46

259

r

p

11/19/28

22.4

35.3

8.12

38

260

50-0

r

P

11/19/28

46

263

100

oc

n

11/21/28

22.6

35.4

8.17

40

264

r

p

11/21/28

23.3

35.3

8.16

36

265

50

r

p

11/21/28

23.2

35.3

8.16

40

48

274

r

p

11/25/28

23.6

36.4

8.23

13

49a

283

r

n

11/28/28

(23.3)

(36.1)

(8.25)

(13)*

50

284

r

n

11/29/28

23.2

36.0

8.23

13

287

oc

p

11/29/28

23.2

36.0

8.23

13

288

50

r

p

11/29/28

22.0

36.0

8.23

13

50a

290

r

n

11/30/28

(23.0)

(35.8)

(8.22)

(13)*

292

r

n

11/30/28

(23.0)

(35.8)

(8.22)

(13)*

51

295

100

r

n

12/ 1/28

20.0

35.6

8.22

17

297

50

r

p

12/ 1/28

20.5

35.6

8.22

16

53

304

50

r

n

12/ 5/28

21.2

35.8

8.20

13

306

r

p

12/ 5/28

22.6

35.7

8.22

13

53a

310

r

n

12/10/28

(23.0)

(35.6)

(8.22)

(11)*

311

r

n

12/10/28

23.0)

(35.6)

(8.22)

(11 *

313

r

n

12/10/28

(23.0)

(35.6)

(8.22)

(11)*

54

320

50

r

n

12/14/28

19.8

35.4

8.18

17

322

r

p

12/14/28

23.4

35.5

8.22

9

63a

385

r

n

1/ 1/29
1/ 2/29

(20.6)

(34.6)

(8.10)

(21)*
(21)*

388

r

n

(20.6)

(34.6) (8.10)

393

r

n

1/ 3/29

(20.6)

34.6

8.10
(8.11)

(21)*

64a

401

r

n

1/ 3/29

(20.4

(34.6)

(22 *

403

r

n

1/ 4/29

(20.4

(34.6

(8.11
(8.11)

(22 *

404

oc

n

1/ 4/29

(20.4)

(34.6)

(22)*

65

408

oc

p

1/ 5/29

20.2

34.5

8.10

24

79

481

r

n

2/22/29

25.2

36.0

8.17

34

484

r

p

2/22/29

25.2

36.0

8.17

34

82

496

r

n

2/28/29

27.2

36.3

8.21

34

497

50

r

n

2/28/29

27.2

36.3

8.21

34

498

r

P

2/28/29

27.2

36.3

8.21

34

86

518

r

P

3/ 9/29

28.2

36.2

8.29

20

91

542

r

p

3/27/29

28.7

35.1

8.30

21

93

550

r

n

3/31/29

28.7

34.7

8.30

28

551

50

r

n

3/31/29

28.5

34.8

8.30

28

552

r

p

3/31/29

28.7

34.7

8.30

28

553

100

r

p

3/31/29

27.6

35.9

8.27

29

97

574

oc

n

4/28/29

28.3

35.2

8.16

24

576

100

r

n

4/28/29

27.6

35.6

8.15

25

577

r

P

4/28/29

28.3

35.2

8.16

24

100

597

100

r

n

5/ 4/29

27.6

34.7

8.22

12

101

605

100

r

n

5/ 7/29

25.3

35.0

8.23

8

103

616

50

r

n

5/11/29

25.9

35.2

8.25

5

618

r

P

5/11/29

26.0

35.0

8.25

5

105

630

c

P

5/15/29

26.9

34.9

8.23

5

108

648

100

r

n

5/27/29

25.3

35.0

8.23

4

139

854

50

r

p

9/22/29

25.8

34.9

8.31

6

142

878

100

r

P

10/ 7/29

16.6

34.5

8.27

7

144

887

r

P

10/11/29

23.3

35.0

8.37

6

145

893

r

p

10/13/29

22.3

34.6

8.29

6

892

r

n

10/13/29

22.3

34.6

8.29

6

146

901

50

r

P

10/15/29

22.4

34.9

8.37

6

149

927

r

P

10/21/29

23.5

35.0

8.34

6

150

929

r

n

10/23/29

25.6

34.7

8.39

7

930

50

r

n

10/23/29

25.9

34.8

931

100

r

n

10/23/29

19.6

34.7

8.32

11

151

938

50

r

n

10/25/29

18.3

34.4

. . .

941

r

P

10/25/29

26.0

34.0

152

944

r

n

10/27/29

27.5

33.7

8.35

'20

945

50

r

n

10/27/29

14.2

34.5

7.87

53

946

100

r

n

10/27/29

11.4

34.7

7.76

157

978

r

n

11/ 6/29

27.1

35.3

8.27

'47

979

50

r

n

11/ 6/29

27.1

35.2

8.32

60

158

983

r

n

11/ 8/29

28.2

35.6

8.34

36

985

100

r

n

11/ 8/29

27.2

35.9

8.39

48

159

992

100

r

n

11/12/29

28.0

35.8

8.37

23

DISTRIBUTIONAL AND ENVIRONMENTAL RECORDS

79

Table 19. Distributional and environmental records for Goniodoma polyedricum Pouchet

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature

Cc)

Salinity
(o/oo)

PH

P04

mg/m-'

Atl

antic

1

1

oc

n

5/12/28

24.0

36.2

8.16

34

lb

7

50

r

n

5/16/28

(22.2)

(36.3)
(36.5)

(8.25)

(38)*
(36)*

8

100

oc

n

5/16/28

(20.3)

(8.18)

2

14

r

n

5/18/28

20.5

36.4

8.23

58

3

20

r

n

5/21/28

15.5

36.1

8.15

99

5a

33

oc

n

5/30/28

(13.7)

(35.8)
(35.8)

(8.17)

(19)*
(19)*

34

r

n

5/30/28

(13.7)

(8.17)

6

36

50

oc

n

5/31/28

11.6

35.6

8.12

32

37

100

oc

n

5/31/28

11.3

35.6

8.08

41

6b

44

r

n

6/ 2/28

(10.6)
(10.6

(35.4)

(8.12)

(28)*

45

00

n

6/ 2/28

35.4)

(8.12)

(28*

46

oc

n

6/ 2/28

(10.6

35.4

(8.12

(28*

6c

48

r

n

6/ 3/28

(10.6

(35.4)

8.12)

28)*

13a

89

r

n

8/ 8/28

(16.3)

(34.0)

(8.13)

(15)*

15

97

oc

P

8/11/28

24.8

36.4

8.21

11

98

50

r

P

8/11/28

19.8

36.5

8.21

8

101

50

r

n

8/11/28

19.8

36.5

8.21

8

102

100

r

n

8/11/28

18.4

36.4

8.20

19

16

103

r

P

8/13/28

25.9

36.2

8.24

8

104

50

r

P

8/13/28

24.4

36.4

8.23

8

107

50

r

n

8/13/28

24.4

36.4

8.23

8

108

100

oc

n

8/13/28

19.9

36.5

8.17

13

17

110

50

r

P

8/15/28

21.9

36.6

8.28

12

111

r

n

8/15/28

26.2

36.6

8.29

9

112

50

oc

n

8/15/28

21.9

36.6

8.28

12

113

100

r

n

8/15/28

19.3

35.5

8.23

9

18

114

oc

p

8/17/28

27.0

37.0

8.23

5

115

50

r

p

8/17/28

22.4

36.8

8.24

5

118

50

oc

n

8/17/28

22.4

36.8

8.24

5

19

121

50

r

P

8/20/28

25.2

37.1

8.27

5

122

r

n

8/20/28

26.6

37.0

8.34

5

123

50

oc

n

8/20/28

25.2

37.1

8.27

5

124

100

r

n

8/20/28

22.4

37.0

8.25

5

20

125

r

P

8/22/28

26.0

36.6

8.37

5

126

50

r

P

8/22/28

25.8

36.6

8.26

3

127

100

r

P

8/22/28

22.6

36.7

8.19

5

128

r

n

8/22/28

26.0

36.6

8.37

5

130

100

r

n

8/22/28

22.6

36.7

8.19

5

20a

131

r

n

8/23/28

(26.6)

(36.3)

(8.32)

(4f
(4)*

21

135

oc

n

8/24/28

(26.6)

(36.3) (8.32)

136

50

r

n

8/24/28

24.4

36.2

8.26

4

22

139

r

P

8/27/28

26.7

36.0

8.26

8

144

100

r

n

8/27/28

17.5

36.1

7.99

123

23

145

r

p

8/29/28

27.2

35.9

8.25

4

150

100

r

n

8/29/28

16.6

36.0

8.18

75

24

151

r

p

8/31/28

27.2

35.2

8.32

4

155

50

r

n

8/31/28

23.1

36.0

8.14

8

25

157

oc

p

9/ 3/28

27.5

35.6

8.31

5

158

50

r

p

9/13/28

21.5

36.0

8.22

12

161

SO

r

n

9/13/28

21.5

36.0

8.22

12

26

163

r

P

9/ 5/28

27.6

36.0

8.30

5

28

177

50

r

n

9/11/28

26.7

36.3

8.26

4

178

100

r

n

9/11/28

22.8

36.6

8.22

7

29

183

50

r

n

9/13/28

27.2

36.2

8.29

3

184

100

r

n

9/13/28

23.1

36.6

8.21

8

30

186

50

r

P

9/15/28

27.8

36.1

8.29

3

31

191

r

n

10/ 3/28

28.5

34.4

8.27

2

32

194

c

n

10/ 5/28

28.0

36.0

8.23

2

194a

oc

P

10/ 5/28

28.0

36.0

8.23

2

195

50

r

n

10/ 5/28

27.2

36.0

8.24

2

196

100

oc

n

10/ 5/28

22.2

36.4

8.10

30

33

197a

oc

P

10/ 8/28

28.5

35.6

8.23

4

199a

100

r

P

10/ 8/28

22.3

36.5

8.18

23

34

200

oc

n
P

10/ 9/28
icif ic

28.5

35.9

8.28

2

35

204

50

r

n

10/26/28

16.8

34.7

7.92

138

205

100

r

n

10/26/28

14.4

34.9

7.88

189

206

oc

P

10/26/28

27.4

29.7

8.31

15

35a

208

oc

n

10/26/28

(27.0)

(30.7)

(8.27)

(16)*

209

c

n

10/27/28

(27.0

(30.7

8.27)

16 *

35b

212

c

n

10/28/28

(27.0)

(30.7)

(8.27)

(16 •

36

213

oc

n

10/30/28

26.5

31.6

8.23

16

214

50

r

n

10/30/28

18.5

34.5

8.03

122

215

100

r

n

10/30/28

14.4

34.9

7.85

149

216

r

P

10/30/28

26.5

31.6

8.23

16

80

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

Table 19. Distributional and environmental records for Goniodoma polyedricum Pouchet- -Continued

Station

Sample

Depth

(m)

Relative
abundance

Apparatus

Date

Temperature

Cc)

Salinity
(o/oo)

PH

mg/m-'

Pacifi

37

217

oc

n

218

50

r

n

219

100

r

n

220

r

P

38

222

r

n

223

50

r

n

224

100

r

n

40

229

r

n

231

100

r

n

232

c

P

233

50

r

P

234

100

r

P

41

238

r

P

239

100

r

P

41a

240

oc

n

42

241

r

n

242

50

r

n

243

100

r

n

43

248

50

r

P

44

253

r

P

254

50

r

P

255

100

r

P

45

257

50

r

n

258

100

r

n

259

oc

P

260

50

r

P

46

262

50

r

n

263

100

r

n

264

r

P

47

266

r

n

267

50

r

n

268

100

r

n

269

r

P

270

50

r

P

48

271

oc

n

272

50

oc

n

273

100

oc

n

274

oc

P

275

50

oc

P

49

277

oc

n

278

50

r

n

279

100

oc

n

280

oc

P

281

50

oc

P

282

100

oc

P

49a

283

oc

n

50

284

oc

n

285

50

oc

n

286

100

oc

n

287

oc

P

288

50

r

P

289

100

oc

P

51

290

c

n

291

oc

n

292

oc

n

294

50

oc

n

295

100

oc

n

296

r

P

297

50

r

P

298

100

r

P

52

300

50

r

n

301

100

oc

n

302

oc

P

53

304

50

c

n

305

100

oc

n

306

oc

P

53a

307

r

n

308

oc

n

310

oc

n

311

oc

n

312

oc

n

313

oc

n

316

r

n

53b

317

oc

n

54

320

50

oc

n

321

100

oc

n

c --Continued
11/ 1/28
11/ 1/28
11/ 1/28
11/ 1/28
11/ 3/28
11/ 3/28
11/ 3/28
11/ 8/28
11/ 8/28
11/ 8/28
11/ 8/28
11/ 8/28
11/10/28
11/10/28
11/12/28
11/13/28
11/13/28
11/13/28
11/15/28
11/17/28
11/17/28
11/17/28
11/19/28
11/19/28
11/19/28
11/19/28
11/21/28
11/21/28
11/21/28
11/23/28
11/23/28
11/23/28
11/23/28
11/23/28
11/25/28
11/25/28
11/25/28
11/25/28
11/25/28
11/27/28
11/27/28
11/27/28
11/27/28
11/27/28
11/27/28
11/28/28
11/29/28
11/29/28
11/29/28
11/29/28
11/29/28
11/29/28
12/ 1/28
12/ 1/28
12/ 1/28
12/ 1/28
12/ 1/28
12/ 1/28
12/ 1/28
12/ 1/28
12/ 3/28
12/ 3/28
12/ 3/28
12/ 5/28
12/ 5/28
12/ 5/28
12/ 6/28
12/ 6/28
12/10/28
12/10/28
12/10/28
12/10/28
12/12/28
12/12/28
12/14/28
12/14/28

27.1

31.7

8.28

15

18.8

34.5

8.00 121

15.1

34.9

7.82 153

27.1

31.7

8.28

L5

26.5

32.9

8.33

20

21.3

34.4

8.14

35

15.6

34.9

7.91 166

22.2

33.7

8.21

24

13.9

35.0

7.85 159

22.2

33.7

8.21

24

15.3

34.9

7.87 161

13.9

35.0

7.85 159

20.4

34.2

8.11

32

14.5

35.0

7.91 152

(19.6)

(34.5)

(8.09) (39)*

18.7

34.7

8.06

45

17.2

34.9

7.99

68

13.8

35.0

7.91 150

17.0

34.9

7.93

80

20.7

34.9

8.03

38

20.4

34.9

8.04

34

13.8

35.0

7.85

70

22.4

35.2

8.13

46

18.6

35.1

8.00

50

22.4

35.3

8.12

38

22.4

35.2

8.13

46

23.2

35.3

8.16

40

22.5

35.4

8.17

40

23.3

35.3

8.16

36

23.9

36.0

8.23

17

23.8

36.0

8.23

20

22.7

36.2

8.23

20

23.9

36.0

8.23

17

23.8

36.0

8.23

20

23.6

36.4

8.23

13

23.6

36.4

8.24

16

22.7

36.3

8.26

16

23.6

36.4

8.23

13

23.6

36.4

8.24

16

23.4

36.2

8.27

13

22.6

36.1

8.26

13

21.6

35.9

8.26

13

23.4

36.2

8.27

13

22.6

36.1

8.26

13

21.6

35.9

8.26

13

(23.2)
(23.2)

(36.0) (8.23) (
(36.0) (8.23) (

13)*
13)*

22.0

35.9

8.23

13

20.5

35.7

8.22

13

23.2

36.0

8.23

13

22.0

35.9

8.23

13

20.5

35.7

8.22

13

22.8

35.6

8.22

16

22.8

35.6

8.22

16

22.8

35.6

8.22

16

20.5

35.6

8.22

17

20.0

35.6

8.22

17

22.8

35.6

8.22

16

20.5

35.6

8.22

17

20.0

35.6

8.22

17

20.2

35.6

8.20

8

18.2

35.2

8.17

8

22.5

35.4

8.21

8

21.2

35.8

8.20

13

19.9

35.6

8.19

13

22.6

35.7

8.22

13

(23.0

(35.6

(8.22)

11)*

23.0

35.6

8.22)

11 *

23.0

(35.6

8.22)

11 *

23.0

(35.6

8.22
8.22

11 *

23.0

(35.6

11)*

23.0

35.6

8.22

11 •

23.0

35.6

8.22

11 •

(23.0

(35.6

(8.22)

11)'

19.8

35.4

8.18

17

18.7

35.4

8.16

20

DISTRIBUTIONAL AND ENVIRONMENTAL RECORDS

81

Table 19. Distributional and environmental records for Goniodoma polyedricum Pouchet--Continued

Station

Sample

Depth

(m)

Relative
abundance

Apparatus

Date

Temperature

(°C)

Salinity
(o/oo)

PH

PO4

mg/m^

Pacific

54

322

00

P

55

324

50

oc

n

325

100

r

n

56

328

oc

n

329

50

r

n

330

100

r

n

331

r

P

332

50

oc

P

333

100

r

P

57

334

oc

n

335

r

n

336

50

r

n

338

r

P

60

361

r

n

61a

369

r

n

62

373

100

r

n

374

r

P

376

100

r

P

63

377

r

n

378

r

n

379

r

n

380

50

r

n

381

100

r

n

382

r

P

385

r

n

386

oc

n

389

r

n

391

r

n

392

r

n

393

r

n

64

394

r

n

398

r

P

400

100

r

P

402

r

n

403

r

n

404

r

n

65

405

r.

n

406

50

r

n

408

r

P

409

50

r

P

66

412

100

r

n

413

r

P

415

100

r

P

67

416

oc

n

417

50

r

n

418

100

oc

n

68

422

r

P

423

50

r

P

69

424

oc

n

425

50

oc

n

426

100

oc

n

427

DC

P

428

50

oc

P

429

100

r

P

70

434

oc

P

71

438

oc

n

439

50

r

n

440

100

r

n

441

oc

P

72

446

r

P

447

50

oc

P

73

449

oc

n

451

50

r

n

452

100

oc

n

453

r

P

455

100

r

P

74

459

r

P

75

462

oc

n

465

r

P

76

467

oc

n

470

r

P

77

473

r

P

474

50

oc

P

78

475

r

n

477

100

oc

n

79

481

r

n

--Continued
12/14/28
12/16/28
12/16/28
12/18/28
12/18/28
12/18/28
12/18/28
12/18/28
12/18/28
12/20/28
12/20/28
12/20/28
12/20/28
12/26/28
12/28/28
12/30/28
12/30/28
12/30/28
12/31/28
12/31/28
1/ 1/29
1/ 1/29
1/ 1/29
1/ 1/29
1/ 1/29
1/ 1/29
1/ 2/29
1/ 3/29
1/ 3/29
1/ 3/29
1/ 3/29
1/ 3/29
1/ 3/29
1/ 4/29
1/ 4/29
1/ 4/29
1/ 5/29
1/ 5/29
1/ 5/29
1/ 5/29
1/ 7/29
1/ 7/29
1/ 7/29
1/ 8/29
1/ 8/29
1/ 8/29
1/10/29
1/10/29
1/12/29
1/12/29
1/12/29
1/12/29
1/12/29
1/12/29
1/13/29
2/ 6/29
2/ 6/29
2/ 6/29
2/ 6/29
2/ 8/29
2/ 8/29
2/10/29
2/10/29
2/10/29
2/10/29
2/10/29
2/12/29
2/14/29
2/14/29
2/16/29
2/16/29
2/18/29
2/18/29
2/20/29
2/20/29
2/22/29

23.4

35.5

8.22

9

18.7

35.0

8.18

12

16.7

34.9

7.17

12

20.8

34.9

8.13

9

18.5

35.1

8.14

9

16.6

34.8

8.11

12

20.8

34.9

8.13

9

18.5

35.1

8.14

9

16.6

34.8

8.11

12

19.0

34.5

8.14

20

19.0

34.5

8.14

20

15.6

34.3

8.14

21

19.0

34.5

8.14

20

15.0

34.0

8.07

50

(18.1)

(34.1)

(8.09)

(39)*

13.1

34.2

8.06

48

19.2

34.2

8.12

32

13.1

34.2

8.06

48

20.5

34.6

8.07

21

20.5

34.6

8.07

21

20.5

34.6

8.07

21

17.0

34.6

8.08

25

15.6

34.6

8.08

24

20.5

34.6

8.07

21

20.5

34.6

8.07

21

20.5

34.6

8.07

21

20.5

34.6

8.07

21

20.5

34.6

8.07

21

20.5

34.6

8.07

21

20.5

34.6

8.07

21

20.6

34.6

8.12

21

20.6

34.6

8.12

21

15.8

34.5

8.10

32

20.6

34.6

8.12

21

20.6

34.6

8.12

21

20.6

34.6

8.12

21

20.2

34.5

8.10

24

16.5

34.5

8.10

25

20.2

34.5

8.10

24

16.5

34.5

8.10

25

17.8

34.9

8.12

21

19.4

34.7

8.10

29

17.8

34.9

8.12

21

19.3

34.9

8.11

21

17.4

34.7

8.11

20

16.2

34.6

8.05

40

19.2

35.1

8.14

29

18.2

35.0

8.14

29

21.1

35.2

8.12

62

17.4

35.1

7.99

151

14.6

34.8

7.86

198

12.1

35.2

8.12

62

17.4

35.1

7.99

151

14.6

34.8

7.86

198

21.2

35.1

8.05

103

23.5

35.2

8.13

58

16.7

35.1

7.90

150

13.9

35.0

7.71

220

23.5

35.2

8.13

58

24.9

35.3

8.16

50

18.7

35.4

8.12

60

25.3

35.4

8.21

44

18.7

35.4

8.05

122

14.7

35.0

7.80

178

25.3

35.4

8.21

44

14.7

35.0

7.80

178

24.2

35.6

8.17

68

22.8

35.8

8.18

44

22.8

35.8

8.18

44

23.4

35.9

8.15

50

23.4

35.9

8.15

50

23.7

36.0

8.19

16

23.5

36.0

8.19

16

24.6

36.0

8.17

32

21.9

36.2

8.14

34

25.2

36.0

8.17

34

82

STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

Table 19. Distributional and environmental records for Goniodoma polyedricum Pouchet- -Continued

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature

(°C)

Salinity
(o/oo)

pH

mg/m"*

Pacific

--Continued

79

483

100

oc

n

2/22/29

21.8

36.2

8.13

45

484

r

P

2/22/29

25.2

36.0

8.17

34

485

50

r

p

2/22/29

24.5

36.1

8.17

34

80

486

r

n

2/24/29

26.0

35.9

8.20

36

487

50

r

n

2/24/29

25.9

36.0

8.19

29

488

oc

P

2/24/29

26.0

35.9

8.20

36

489

50

r

P

2/24/29

25.9

36.0

8.19

29

81

491

oc

n

2/26/29

26.5

35.8

8.19

38

492

50

r

n

2/26/29

26.4

35.9

8.19

38

493

r

P

2/26/29

26.5

35.8

8.19

38

494

50

r

P

2/26/29

26.4

35.9

8.19

38

82

497

50

r

n

2/28/29

27.2 '

36.3

8.21

34

498

r

P

2/28/29

27.2

36.3

8.21

34

83

501

oc

n

3/ 2/29

27.5

36.3

8.24

29

502

50

oc

n

3/ 2/29

27.4

36.5

8.24

25

503

r

P

3/ 2/29

27.5

36.3

8.24

29

84

505

r

n

3/ 4/29

27.8

36.2

8.23

24

506

50

r

n

3/ 4/29

27.5

36.4

8.21

24

507

r

P

3/ 4/29

27.8

36.2

8.23

24

85

510

r

n

3/ 6/29

27.9

36.2

8.22

40

511

50

r

n

3/ 6/29

27.8

36.2

8.22

40

512

r

P

3/ 6/29

27.9

36.2

8.22

40

513

50

r

P

3/ 6/29

27.8

36.2

8,22

40

86

515

oc

n

3/ 9/29

28.3

36.2

8.29

20

516

oc

n

3/ 9/29

28.3

36.2

8.29

20

518

oc

P

3/ 9/29

28.3

36.2

8.29

20

519

50

r

P

3/ 9/29

27.4

36.2

8.29

17

87

521

r

n

3/11/29

27.8

36.1

8.28

17

522

50

r

n

3/11/29

26.5

36.1

8.26

20

523

r

P

3/11/29

27.8

36.1

8.28

17

524

50

oc

P

3/11/29

26.5

36.1

8.26

20

88

526

oc

n

3/21/2D

28.5

35.9

8.23

16

527

50

r

n

3/21/29

28.4

35.9

8.25

13

89

528

r

n

3/23/29

28.4

35.6

8.25

21

529

50

r

n

3/23/29

28.6

35.8

8.27

12

530

oc

P

3/23/29

28.4

35.6

8.25

21

531

100

r

P

3/23/29

26.4

36.0

8.24

12

532

r

n

3/23/29

28.4

35.6

8.25

21

90

533

oc

n

3/25/29

28.5

35.5

8.27

21

534

50

oc

n

3/25/29

28.6

35.6

8.26

21

535

oc

P

3/25/29

28.5

35.5

8.27

21

536

50

r

P

3/25/29

28.6

35.6

8.26

21

91

540

oc

n

3/27/29

28.7

35.1

8.30

21

541

50

oc

n

3/27/29

28.5

35.2

8.30

24

542

r

p

3/27/29

28.7

35.1

8.30

21

543

50

r

p

3/27/29

28.5

35.2

8.30

24

544

100

r

P

3/27/29

25.8

36.0

8.25

30

92

545

oc

n

3/29/29

28.5

35.3

8.29

28

93

550

c

n

3/31/29

28.7

34.7

8,30

28

551

50

oc

n

3/31/29

28.5

34.8

8.30

28

552

oc

P

3/31/29

28.7

34.7

8.30

28

94

557

r

n

4/22/29

29.5

34.7

8.25

14

559

100

r

n

4/22/29

28.5

35.6

8.21

25

562

100

r

P

4/22/29

28.5

35.6

8.21

25

95

563

50

oc

n

4/24/29

29.3

34.9

8.24

16

564

100

oc

n

4/24/29

28.5

35.4

8.22

21

565

r

P

4/24/29

29.4

34.7

8.26

14

566

50

r

P

4/24/29

29.3

34.9

8.24

16

567

100

r

P

4/24/29

28.5

35.4

8.22

21

568a

r

n

4/24/29

29.4

34.7

8.26

14

96

568

oc

n

4/26/29

29.3

35.3

8.23

12

569

50

oc

n

4/26/29

29.2

35.3

8.23

12

570

100

oc

n

4/26/29

28.2

35.7

8.19

25

97

574

c

n

4/28/29

28.3

35.2

8.16

24

575

50

oc

n

4/28/29

28.0

35.4

8.16

21

577

r

P

4/28/29

28.3

35.2

8.16

24

98

584

oc

P

4/30/29

27.0

35.3

8.16

24

588

100

oc

P

4/30/29

26.7

35.4

8.14

32

99

589

oc

n

5/ 2/29

27.9

34.9

8.21

12

590

50

oc

n

5/ 2/29

27.8

34.9

8.22

12

591

100

oc

n

5/ 2/29

27.8

35.0

8.22

17

592

oc

P

5/ 2/29

27.9

34.9

8.21

12

594

100

r

P

5/ 2/29

27.8

35.0

8.22

17

595

r

n

5/ 2/29

27.9

34.9

8.21

12

100

596

50

oc

n

5/ 4/29

27.6

34.7

8.21

10

597

100

oc

n

5/ 4/29

27.6

34.7

8.22

12

DISTRIBUTIONAL AND ENVIRONMENTAL RECORDS

83

Table 19. Distributional and environmental records for Goniodoma polyedricum Pouchet- -Continued

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature

(°C)

Salinity
(o/oo)

PH

PO4

mg/m3

Pacific

--Continued

100

598

c

P

5/ 4/29

27.7

34.7

8.21

10

599

50

oc

p

5/ 4/29

27.6

34.7

8.21

10

602

100

oc

P

5/ 4/29

27.6

34.7

8.22

12

101

603

c

n

5/ 7/29

26.3

34.7

8.24

8

604

50

c

n

5/ 7/29

26.2

34.7

8.24

8

606

r

p

5/ 7/29

26.3

34.7

8.24

8

102

609

oc

n

5/ 9/29

25.8

35.0

8.24

8

610

50

oc

n

5/ 9/29

25.8

35.0

8.24

8

611

100

oc

n

5/ 9/29

25.6

35.0

8.23

8

612

oc

p

5/ 9/29

25.8

35.0

8.24

8

613

50

r

p

5/ 9/29

25.8

35.0

8.24

8

103

615

oc

n

5/11/29

26.0

35.0

8.25

5

616

50

oc

n

5/11/29

25.8

35.2

8.25

5

617

100

oc

n

5/11/29

24.8

35.2

8.25

5

618

r

P

5/11/29

26.0

35.0

8.25

5

619

50

r

P

5/11/29

25.8

35.2

8.25

5

104

621

oc

n

5/13/29

26.1

35.2

8.24

7

622

50

oc

n

5/13/29

25.8

35.2

8.24

7

624

oc

P

5/13/29

26.1

35.2

8.24

7

625

50

oc

P

5/13/29

25.8

35.2

8.24

7

105

627

50

c

n

5/15/29

26.8

34.9

8.23

5

628

50

r

n

5/15/29

26.8

34.9

8.23

5

629

100

oc

n

5/15/29

25.2

35.1

8.23

5

630

oc

P

5/15/29

26.9

34.9

8.23

5

631

50

oc

P

5/15/29

26.8

34.9

8.23

5

106

633

oc

n

5/17/29

27.2

35.0

8.23

5

635

100

oc

n

5/17/29

25.6

35.1

8.23

5

637

50

r

P

5/17/29

27.0

35.0

8.23

5

638

100

r

p

5/17/29

25.6

35.1

8.23

5

107

640

50

oc

n

5/19/29

27.9

34.4

8.23

641

100

oc

n

5/19/29

26.8

34.9

8.23

11

642

r

P

5/19/29

28.0

34.4

8.23

644

100

oc

P

5/19/29

26.8

34.9

8.23

11

645

50

r

p

5/19/29

27.9

34.4

8.23

108

646

r

n

5/27/29

28.4

35.0

8.25

647

50

oc

n

5/27/29

26.8

35.0

8.25

648

100

oc

n

5/27/29

25.2

35.0

8.23

650

50

r

P

5/27/29

26.8

35.0

8.24

Guam

652

oc

n

5/--/29

109

654

oc

n

5/29/29

27.4

35.6

8.23

'3

657

r

5/29/29

27.4

35.0

8.23

3

658

50

oc

p

5/29/29

23.1

35.0

8.22

3

659

100

oc

p

5/29/29

19.4

34.8

8.18

5

660

r

p

5/29/29

27.4

35.0

8.23

3

110

661

r

n

5/31/29

23.9

34.7

8.18

5

662

50:

r

n

5/31/29

18.4

34.8

8.16

7

663

100

oc

n

5/31/29

17.9

34.7

8.14

11

^

664

oc

p

5/31/29

23.9

34.7

8.18

5

665

50

r

p

5/31/29

18.4

34.8

8.16

7

666

667
668

100

r

P

5/31/29

17.9

34.7

8.14

11

111

"

oc

n

6/ 3/29

20.1

34.5

8.18

5

669

50

r

n

6/ 3/29

19.4

34.6

8.17

5

671

oc

p

6/ 3/29

20.1

34.5

8.18

5

672

50

r

p

6/ 3/29

19.4

34.6

8.17

5

112

674

r

n

6/ 5/29

23.2

34.6

8.22

7

675

50

oc

n

G/ 5/29

21.7

34.6

8.23

7

676

100

oc

n

6/ 5/29

19.8

34.7

8.20

8

677

oc

p

6/ 5/29

23.2

34.6

8.22

7

678

50

r

P

6/ 5/29

21.7

34.6

8.23

7

679

100

r

P

6/ 5/29

19.8

34.7

8.20

8

113

681

50

oc

n

6/25/29

23.8

34.6

8.25

5

682

100

oc

n

6/25/29

^1.5

34.7

8.23

8

683

oc

p

6/25/29

24.2

34.5

8.25

5

685

100

r

p

6/25/29

21.5

34.7

8.23

8

115

695

r

p

6/29/29

20.6

34.6

8.19

4

117

710

100

r

n

7/ 3/29

8.8

34.1

7.98

84

130

792

r

p

9/ 4/29

16.2

33.4

8.34

36

131

794

r

p

9/ 6/29

19.3

33.4

8.34

132

797

oc

n

9/ 8/29

21.0

33.9

8.34

15

801

r

p

9/ 8/29

21.0

33.9

8.34

15

798

50

r

n

9/ 8/29

17.6

33.9

8.33

19

802

50

r

P

9/ 8/29

17.6

33.9

8.33

19

803

100

r

P

9/ 8/29

14.3

33.4

8.30

16

133

804

r

n

9/10/29

22.7

34.7

8.47

7

806

100

r

n

9/10/29

18.4

34.8

8.31

7

84 STUDIES IN THE MORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

Table 19

. Distributional and environmental records lor Goniodoma polyedricum Pouchet--

Continued

Station

Sample

Deptli
(m)

Relative
abundance

Apparatus

Date

Temperature

rc)

Salinity
(o/oo)

PH

mg/m"*

Pacific

--Continued

133

814

100

r

p

9/10/29

18.4

34.8

8.31

7

134

809

50

r

n

9/12/29

19.8

34.6

8.34

6

817

100

r

p

9/12/29

18.1

34.6

8.34

6

135

820

r

n

9/14/29

23.8

35.1

8.37

7

821

50

r

n

9/14/29

21.5

35.0

8.37

5

825

50

r

p

9/14/29

21.5

35.0

8.37

5

826

100

r

P

9/14/29

18.7

34.8

8.34

5

136

827

r

n

9/16/29

24.6

35.4

8.37

3

829

100

oc

n

9/16/29

18.6

35.0

8.39

3

833

50

r

p

9/16/29

21.4

35.1

8.39

3

834

100

r

p

9/16/29

18.6

35.0

8.39

3

137

837

50

r

p

9/18/29

24.4

35.1

8.34

4

138

843

oc

n

9/26/29

26.1

34.8

8.35

5

847

r

p

9/26/29

26.1

34.8

8.35

5

844

50

r

n

9/26/29

25.6

34.7

8.30

3

845

100

oc

n

9/26/29

22.2

34.8

8.31

3

139

853

r

p

9/22/29

26.7

34.8

8.34

6

850

50

oc

n

9/22/29

25.8

34.9

8.31

6

854

50

r

p

9/22/29

25.8

34.9

8.31

6

140

860

r

p

10/ 3/29

26.9

35.0

8.42

7

957

50

oc

n

10/ 3/29

26.9

35.0

8.39

7

861

50

r

P

10/ 3/29

26.9

35.0

8.39

7

858

100

oc

n

10/ 3/29

25.5

35.0

8.34

7

863

100

r

p

10/ 3/29

25.5

35.0

8.34

7

141

864

r

n

10/ 5/29

25.9

35.2

8.34

5

868

r

p

10/ 5/29

25.9

35.2

8.34

5

865

50

oc

n

10/ 5/29

24.8

35.3

8.34

5

869

50

r

P

10/ 5/29

24.8

35.3

8.34

5

871

100

r

P

10/ 5/29

20.0

35.0

8.33

5

142

872

oc

n

10/ 7/29

24.1

34.8

8.33

5

874

100

oc

n

10/ 7/29

16.6

34.4

8.27

7

876

oc

P

10/ 7/29

24.1

34.8

8.33

5

877

50

oc

P

10/ 7/29

21.8

34.8

8.30

5

878

100

oc

P

10/ 7/29

16.6

34.4

8.27

7

879

100

oc

P

10/ 7/29

16.6

34.4

8.27

7

143

881

oc

n

10/ 9/29

22.4

34.4

8.30

6

884

r

p

10/ 9/29

22.4

34.4

8.30

6

882

50

oc

n

10/ 9/29

19.0

34.2

8.34

6

885

50

r

P

10/ 9/29

19.0

34.2

8.34

6

883

100

r

n

10/ 9/29

13.8

34.1

8.30

10

144

886

r

n

10/11/29

23.3

35.0

8.37

6

889

100

r

P

10/11/29

16.6

34.5

8.37

6

145

890

c

n

10/13/29

22.3

34.6

8.29

6

893

r

p

10/13/29

22.3

34.6

8.29

6

891

50

oc

n

10/13/29

18.7

34.3

8.34

6

894

50

r

P

10/13/29

18.7

34.3

8.34

6

892

100

r

n

10/13/29

16.0

34.1

8.31

6

895

100

r

p

10/13/29

16.0

34.1

8.31

6

146

896

r

n

10/15/29

22.4

34.9

8.37

6

897

50

r

n

10/15/29

22.4

34.9

8.30

6

147

903

r

n

10/17/29

23.3

35.3

8.26

8

907

r

p

10/17/29

23.3

35.3

8.26

8

904

50

r

n

10/17/29

23.1

35.3

8.29

5

909

100

r

P

10/17/29

19.2

35.0

8.29

5

148

910

r

n

10/19/29

23.4

35.2

917

r

P

10/19/29

23.4

35.2

. .

912

100

r

n

10/19/29

20.0

35.0

149

920

r

n

10/21/29

23.5

35.0

8.34

' 6

927

r

P

10/21/29

23.5

35.0

8.34

6

928

50

r

P

10/21/29

23.3

35.0

8.37

6

150

929

oc

n

10/23/29

25.6

34.7

8.39

7

930

50

oc

n

10/23/29

22.8

34.8

8.35

10

934

50

r

P

10/23/29

22.8

34.8

8.35

10

931

100

oc

n

10/23/29

19.6

34.6

8.32

11

936

100

r

P

10/23/29

19.6

34.6

8.32

11

151

937

r

n

10/26/29

26.0

34.0

941

r

p

10/26/29

26.0

34.0

938

50

r

n

10/26/29

18.3

34.4

942

50

r

P

10/26/29

18.3

34.4

. . .

. .

939

100

r

n

10/26/29

12.5

34.6

. . .

152

944

r

n

10/27/29

27.4

33.7

8.35

"20

948

r

p

10/27/29

27.4

33.7

8.35

20

945

50

oc

n

10/27/29

14.2

34.5

7.87

53

946

100

r

n

10/27/29

11.4

34.7

7.76

75

153

951

oc

n

10/29/29

28.1

34.2

8.47

7

955

r

P

10/29/29

28.1

34.2

8.47

7

DISTRIBUTIONAL AND ENVIRONMENTAL RECORDS

85

Table 19. Distributional and environmental records for Goniodoma polyedricum Pouchet- -Concluded

Station

Sample

Depth
(m)

Relative
abundance

Apparatus

Date

Temperature

(°C)

Salinity
(o/oo)

PH

mg/m"'

153

952

50

956

50

953

100

957

100

154

959

50

155

965

966

50

967

100

156

972

974

100

157

978

979

50

980

100

158

983

984

50

985

100

159

990

991

50

992

100

160

1000

Pacific

--Concluded
10/29/29

00

n

28.1

r

p

10/29/29

28.1

r

n

10/29/29

20.5

r

P

10/29/29

20.5

r

n

10/31/29

28.2

DC

n

11/ 2/29

27.8

r

p

11/ 2/29

27.7

00

n

11/ 2/29

27.2

00

n

11/ 4/29

27.6

00

n

11/ 4/29

26.4

r

n

11/ 6/29

27.1

r

n

11/ 6/29

27.1

r

n

11/ 6/29

26.8

00

n

11/ 8/29

28.2

00

n

11/ 8/29

28.2

r

n

11/ 8/29

27.6

r

n

11/11/29

28.6

r

n

11/11/29

28.5

r

n

ll/n/29

28.0

r

n

11/13/29

28.6

34.4

8.39

7

34.4

8.39

7

34.7

8.28

31

34.7

8.28

31

34.2

8.40

7

34.9

8.29

29

34.9

8.30

30

35.0

8.30

35

35.0

8.34

28

35.1

8.30

48

35.3

8.27

47

35.2

8.32

60

35.5

8.30

64

35.6

8.34

36

35.6

8.39

50

35.9

8.39

48

35.7

8.37

15

35.7

8.39

15

35.7

8.37

23

35.6

8.37

12

Table 20. Distributional and environmental records for Gonyaulax pacifica Kofoid

Station

Sample

Depth
(m)

Relative
abundance

Apparatus Date

Temperature

(°C)

Salinity
(o/oo)

pH

mg/m-*

Atl

antic

15

98

50

oc

p

8/11/28

19.8

36.5

8.21

8

99

100

DC

p

8/11/28

18.4

36.4

8.20

19

101

50

r

n

8/11/28

19.8

36.5

8.21

8

102

100

CO

n

8/11/28

18.4

36.4

8.20

19

16

104

50

r

P

8/13/28

24.4

36.4

8.23

8

108

100

r

n

8/13/28

19.9

36.5

8.17

13

17

110

50

r

p

8/15/28

21.9

36.6

8.28

12

111

r

n

8/15/28

26.2

36.6

8.29

9

18

114

r

p

8/17/28

27.0

37.0

8.23

5

118

50

r

n

8/17/28

22.4

36.8

8.24

5

115

50

r

P

8/17/28

22.4

36.8

8.24

5

119

100

oc

n

8/17/28

20.4

36.8

8.21

5

19

121

50

r

p

8/20/28

25.2

37.1

8.27

5

123

50

r

n

8/20/28

25.2

37.1

8.27

5

20

126

50

r

p

8/22/28

25.8

36.6

8.26

3

129

50

r

n

8/22/28

25.8

36.6

8.26

3

130

100

r

n

8/22/28

22.6

36.7

8.19

5

21

136

50

r

n

8/24/28

24.4

36.2

8.26

4

137

100

r

n

8/24/28

21.0

36.8

8.20

7

22

143

50

r

n

8/27/28

24.5

36.2

8.21

9

23

149

50

r

n

8/29/28

20.9

36.0

8.14

13

25

158

50

r

p

9/ 3/28

21.5

36.0

8.22

12

161

50

oc

n

9/ 3/28

21.5

36.0

8.22

12

162

100

r

n

9/ 3/28

14.6

35.7

7.93

121

26

164

50

r

p

9/ 5/28

24.1

36.1

8.21

5

165

100

r

p

9/ 5/28

14.9

35.6

8.11

40

27

167

r

p

9/ 7/28

27.5

36.3

8.31

4

171

50

r

n

9/ 7/28

26.0

36.2

8.30

4

28

178

100

r

n

9/11/28

22.8

36.6

8.22

7

29

180

50

r

p

9/13/28

27.2

36.2

8.29

3

30

189

50

r

n

9/15/28

27.8

36.1

8.29

3

Pacific

36

215

100

r

n

10/30/28

14.4

34.9

7.85

149

45

257

50

r

n

11/19/28

22.4

35.2

8.13

46

258

100

r

n

11/19/28

18.6

35.1

8.00

50

259

r

p

11/19/28

22.4

35.3

8.12

33

46

261

r

n

11/21/28

23.3

35.3

8.16

36

262

50

r

n

11/21/28

23.2

35.3

8.16

40

263

100

00

n

11/21/28

22.5

35.4

8.17

40

264

r

p

11/21/28

23.3

35.3

8.16

36

265

50

r

p

11/21/28

23.2

35.3

8.16

40

47

266

r

n

11/23/28

23.9

36.0

8.23

17

267

50

r

n

11/23/28

23.8

36.0

8.23

20

268

100

oc

n

11/23/28

22.7

36.2

8.23

20

270

50

oc

p

11/23/28

23.8

36.0

8.23

20

49

279

100

oc

n

11/27/28

21.6

35.9

8.26

13

86

STUDIES IN THE flORPHOLOGY, TAXONOMY, AND ECOLOGY OF THE PERIDINIALES

Table 20. Distributional and environmental records for Gonyaulax pacifica Kofoid--Continued

Station

Sample

Depth

(m)

Relative
abundance

Apparatus

Date

Temperature

(°C)

Salinity
(o/oo)

pH

PO4

mg/m3

Pacific

--Continued

49

281

50

r

P

11/27/28

22.6

36.1

8.26

13

50

288

50

r

p

11/29/28

22.0

35.9

8.23

13

289

100

r

p

11/29/28

20.5

35.7

8.22

13

51

295

100

r

n

12/ 1/28

20.0

35.6

8.22

17

297

50

r

p

12/ 1/28

20.5

35.6

8.22

17

52

300

50

r

n

12/ 3/28

20.2

35.6

8.20

8

53

304

50

oc

n

12/ 5/28

21.2

35.8

8.20

13

305

100

r

n

12/ 5/28

19.9

35.6

8.19

13

54

320

50

r

n

12/14/28

19.8

35.4

8.18

17

55

324

50

r

n

12/16/28

18.7

35.0

8.18

12

325

100

r

n

12/16/28

16.7

34.9

7.17

12

56

329

50

r

n

12/18/28

18.5

35.1

8.14

9

330

100

r

n

12/18/28

16.6

34.8

8.11

12

64

396

100

r

n

1/ 3/29

15.8

34.5

8.10

32

65

409

50

r

p

1/ 5/29

16.5

34.5

8.10

25

410

100

r

p

1/ 5/29