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A MANUAL OF THE
COMMON INVERTEBRATE ANIMALS

•

A MANUAL

OF THE COMMON

INVERTEBRATE ANIMALS

EXCLUSIVE OF INSECTS

By
HENRY SHERRING PRATT, PH.D.

Professor of Biology in Haverford College and Instructor in Comparative

Anatomy in the Marine Biological Laboratory at Cold

Spring Harbor, Long Island

WITH OVER ONE THOUSAND
ILLUSTRATIONS

CHICAGO

A. C. McCLURG & CO.

1916

Copyright

A. C. McClurg & Co.
1916

Published September, 1916

Copyrighted in Great Britain

TO THE MEMORY OP

Uutiolf Lcuckart

PREFACE

This manual has been written to supply the need which has been felt
in this country for a long time of a book containing descriptions of the
common invertebrate animals, by means of which their names and affinities
can be determined. Excellent general manuals with analytical keys for
the identification of the common insects already exist, but a person wishing
to identify animals belonging to most of the other invertebrate groups
must usually have recourse to technical papers and treatises which are
for the most part inaccessible except to specialists. The book is intended
more particularly for use in the eastern and central portions of the United
States and Canada, and the endeavor has been made to include in it most
of the common invertebrates except insects occurring in this region. In
addition to these, representative species occurring in the western states and
on the Pacific slope are included, as are also other species to which some
special interest attaches and which are found in other parts of the world.
Animals which inhabit the deep sea have not been included except in special
cases where they are representative of their particular groups.

The general plan of the book is similar to that of Leunis' Zoologie,
a standard German work which has for two generations supplied the need
of a general synopsis of animals in Europe, and has been extensively
used elsewhere throughout the world. As in that work, the analytical
tables and descriptions of species of each of the larger groups of animals
are preceded by a morphological description of the group together with
some account of the habits and distribution of the animals. In these
descriptions all the technical terms appearing in the tables 'are explained.
References to the principal authorities upon which the descriptions are
based are given in footnotes, 'as are also references to important treatises
and monographs which have appeared on the animals described.

A knowledge of the historical basis of zoological names adds greatly
to their significance and the author has consequently given >a history
of the nomenclature of each of the larger subdivisions of the animal
kingdom in connection with the morphological description of it. A history
of the general development of the system of classification since the pub-
lication of the tenth edition of Linnaeus' Sy sterna Naturae 'and a brief
survey of the progress of zoological studies in America are added in the
Introduction.

PREFACE

An important object aimed at in these historical notes is to give the
student of American animals a background for his knowledge of zoological
names. In order to attain this object still more fully, brief biographical
notices of the authors of these names, in so far as they appear in this work,
have been introduced at the end of the book.

In the choice of the scientific names of the animals described the author
has endeavored to follow the best usage. He has usually conformed to
the laws of priority established by the International Commission of Nomen-
clature, and has adopted the rulings of the Commission where such have
been made. In a few cases, however, these laws have been disregarded, as,
for instance, in the case of Amceba, Holoihuria, and Physalia, and for the
reason that it seems probable that in such cases the scientific names of the
animals which are now in common use will by common consent be retained.
The author has no desire to be an innovator in this book in the use of
zoological names, but wishes only to use those which will probably in the
future be the names of the animals described.

The name of the author of each species and genus follows the first
mention of it in the descriptions, as is customary, and in those cases in
which the author originally placed his species in some other genus than
the one here employed, his name is in parentheses. Wherever an author's
name appears more than once in the same genus it is usually abbreviated
after the first occurrence. No other abbreviations occur in the text except
in the case of LinnaBus. In all cases where his name appears as the author
of a generic or specific name it is abbreviated to l ' L. "

The illustrations which have been introduced have been copied mostly
from textbooks, special treatises, and monographs, for the use of which
hearty thanks are here extended to their authors, whose names appear in
parentheses after the titles of the figures. Thanks are also due to the
following publishers for permission to make these copies: Doubleday,
Page & Company, Gustav Fischer, Ginn & Company, Henry Holt & Com-
pany, The Macmillan Company, and The Whitaker & Ray-Wiggin Company.

In compiling this book the author has utilized every source of informa-
tion within his reach and is consequently under obligations to very many
people and their published works. His personal obligation to all those
friends who have given valuable advice and assistance, often at the expendi-
ture of much time and labor, is very great indeed. The following are those
to whom he feels a special indebtedness: Mr. Nathan Banks, Dr. H. L.
Clark, Prof. W. R. Coe, Dr. C. B. Davenport, Prof. J. H. Gerould, Prof.
L. von Graff, Prof. C. W. Hargitt, Prof. G. T. Hargitt, Prof. J. S. Kingsley,
Prof. R. von Lendenfeld (deceased), Prof. A. Looss, Dr. M. M. Metcalf,
Prof. E. L. Mark, Prof. S. 0. Mast, Prof. J. P. Moore, Dr. T. Odhner,
Dr. A. E. Ortmann, Prof. R. C. Osburn, Dr. H. A. Pilsbry, Prof. A. A.

PREFACE

Schaeffer, Mr. E. L. Shaffer, Dr. C. W. Stiles, Dr. F. B. Sumner, Prof.
A. L. Treadwell, Dr. T. W. Vaughan, Prof. D. D. Whitney, Prof. H. H.
Wilder, Prof. S. R. Williams, Prof. H. V. Wilson, and Prof. R. H. Wolcott.
The author wishes to thank Prof. J. P. Givler of Southwestern College
for assistance in revising the proof sheets, he having read a large part of
the text and made many corrections and useful suggestions. He also wishes
to acknowledge his indebtedness to Prof. Ludwig von Graff of the University
of Graz, Austria, who extended to him the use of his laboratories and
extensive library during a residence of two semesters in that city, and whose
unfailing courtesy and kindness will ever be gratefully remembered. His
greatest obligation, however, in preparing this work is to Dr. Charles B.
Davenport of Cold Spring Harbor, Long Island, at whose suggestion it
was undertaken in the first place, and without whose constant cooperation
from year to year during its progress it would not have been completed.

H. S. P.
Haverford, Penn.

CONTENTS

PAGE

INTRODUCTION 1

1. The Linnaean system of classifying animals 1

2. The study of animals in America . . 5

SYNOPSIS OF INVERTEBRATE ANIMALS

PHYLUM 1. PROTOZOA 11

Class 1. Sarcodina 14

Class 2. Mastigophora 24

Class 3. Sporozoa 42

Class 4. Infusoria 48

PHYLUM 2. COELENTERATA 70

Subphylum 1. Spongiaria 71

Class 1. Calcarea 75

Class 2. Hexactinellida . 77

Class 3. Demospongiae 78

Subphylum 2. Cnidaria 86

Class 1. Hydrozoa 90

Class 2. Scyphozoa 125

Class 3. Anthozoa 132

Subphylum 3. Ctenophora 150

Class 1. Tentaculata 151

Class 2. Nuda 154

PHYLUM 3. VERMES 155

Subphylum 1. Plathelminthes 156

Class 1. Turbellaria 157

Class 2. Trematodes 171

Class 3. Cestodes 189

Class 4. Nemertea 203

Subphylum 2. Nemathelminthes 213

Class 1. Nematoda 214

Class 2. Gordiacea 225

Class 3. Acanthocephala 228

Subphylum 3. Trochelminthes 230

Class 1. Rotifera 230

Class 2. Gastrotricha .243

Class 3. Kinorhyncha 244

CONTENTS

PAGE

Subphylum 4. Bryozoa 245

Class 1. Entoprocta 246

Class 2. Ectoprocta 248

Subphylum 5. Brachiopoda 264

Subphylum 6. Phoronidea 270

Subphylum 7. Chaetognatha 271

Subphylum 8. Sipunculoidea 272

Class 1. Sipunculida 273

Class 2. Priapulida 276

PHYLUM 4. ANNELIDA 277

Class 1. Archiannelida 280

Class 2. Chaetopoda 281

Class 3. Hirudinea 315

Class 4. Myzostomida 321

PHYLUM 5. ARTHROPODA 323

Class 1. Crustacea 326

Class 2. Arachnoidea 400

Class 3. Tracheata 461

PHYLUM 6. MOLLUSCA 478

Class 1. Amphineura 482

Class 2. Scaphopoda 490

Class 3. Gastropoda 492

Class 4. Pelecypoda 563

Class 5. Cephalopoda 602

PHYLUM 7. ECHINODERMATA 614

Class 1. Crinoidea 619

Class 2. Asteroidea 623

Class 3. Ophiuroidea 633

Class 4. Echinoidea 638

Class 5. Holothurioidea 646

PHYLUM 8. CHORDATA 652

Subphylum 1. Enteropneusta 652

Subphylum 2. Tunicata 655

Class 1. Larvacea 657

Class 2. Thaliacea * 660

Class 3. Ascidiacea 663

Subphylum 3. Leptocardia 671

LIST OF AUTHORS 675

GLOSSARY 693

INDEX . 705

A MANUAL OF THE
COMMON INVERTEBRATE ANIMALS

A MANUAL

OF THE

COMMON INVERTEBRATE ANIMALS

EXCLUSIVE OF INSECTS
INTRODUCTION

1. The Linncean system of classifying animals.— The foundation of
the modern system of classifying animals was laid by Carolus Linnaeus
in the tenth edition of his Systema Naturae, published in 1758. In this
epoch-making work he first applied his fully developed binomial method
of classification to the animal kingdom and arranged all the animals
then known to science according to its rules into classes, orders, genera,
and species.

The essential feature of this system and that which was new at the
tune was the giving of two names to each species of animals, instead of
one, or several, one of which was the specific name and the other the
name of the next higher subdivision in the classification, the genus. The
other important features were the precisions of the terminology employed,
which enables the author to characterize a species in a few words, and
the natural arrangement of the classification in which the position of
each species indicates the degree of its genetic relationship to all the
others.

It is true that predecessors of Linnaeus had anticipated many features
of his system. The idea of a species was already well fixed before his
time, and efforts were made to characterize those then known and the new
ones which were constantly being discovered. But the names given were
often complex and cumbersome and no uniformity existed between the
systems of terminology of different authors. Also the custom of giving
two or more Latin names to a species was frequently in vogue, but a
binomial system, with the definite relation of the specific to the generic
name, was new. The genus, which gives the clue to the natural affinities of
the animal, was peculiarly Linnaeus' invention.

Attempts had also been made by Ray and Klein and other advanced
thinkers to form a system which should express the natural relationships

1

2 INTRODUCTION

of animals, but such attempts were not generally understood or followed,
and most authors still employed unnatural methods of arranging them.
Many still followed Pliny and grouped animals according to their environ-
mental conditions, placing those together having similar methods of life,
as land animals, fresh-water animals, marine animals, flying animals,
etc. Within each group the species were often arranged in alphabetical
order.

LinnaBus' system was very quickly accepted by the scientific world
and went into universal use, and modern zoology may, in a very real sense,
be said to begin with the year 1758.

So radical, however, was Linnaeus' reform that neither the superiority
of his system nor the simplicity of his terminology would probably have
been sufficient thus to procure its instant adoption if they had not been
proposed by a man of his great fame and commanding position in the
world. Linnaeus was considered by his contemporaries, because of his
numerous and important contributions to science and his eminence as a
teacher in the University of Upsala, as the greatest naturalist of all time.
His importance was indicated by the phrase in vogue: Deus creavit;
Linn&us disposuit.

The immediate acceptance of the Linnaean classification had the same
effect upon the study of animals and plants in his day as that of Darwin's
theory of natural selection had almost exactly one hundred years later.
It gave a tremendous impetus to every branch of biological investigation
and started a new era. Systematic zoology, morphology, physiology, and
experimental zoology all attracted able investigators, who studied them
with feverish activity. Comparative studies first became possible as now
the facts of the science were for the first time arranged in something like
an orderly and natural manner, and the next generation saw the rise of the
sciences of comparative anatomy, paleontology, and comparative embry-
ology, and also the first modern speculations on the blood relationships and
the evolution of living things.

All these things gave a new importance to zoology and raised it from
the position it had occupied of a mere annex to medicine to the dignity of
an independent science.

Linnaeus divided the animal kingdom into six classes: Mammalia,
Aves, Amphibia, Pisces, Insecta, and Vermes. The knowledge of this last
class, which included all invertebrate animals except the arthropods, was
in a very confused state and one of the chief objects of the many able
zoologists of the generation immediately following him was to remedy this
condition. The men whose services were greatest in this direction were
0. F. Miiller, Lamarck, and Cuvier. In 1794 Lamarck first distinguished
the vertebrates from the invertebrates and divided the Linnaean class

INTRODUCTION 3

Vermes into the five classes of Mollusca, Insect a, Vermes, Echinodermata,
and Polypi. Thus a long step was taken towards modernizing the system,
and this early effort of Lamarck may be said to be the first modern classi-
fication of animals. He, in his later works, further subdivided the inver-
tebrate types until he had ten, the fundamental idea at the basis of his
classification being that the various groups of animals constitute a single
ascending series which begins with the lowest and ends with the highest.
This principle of the unity of the type found a wide acceptance among the
naturalists of that time and was based upon the law: Natura non facit
saltum.

In 1812 Cuvier published his subdivision of the animal kingdom into
four branches or types and in 1817 his great work Le Eegne Animal, which
established the second great reform of the system, and was destined to
exert an influence only second to that of Linnaeus* Systema Naturae
upon the study of animals and the development of the system. In these
works Cuvier controverted the principle of the unity of type among ani-
mals and taught that, instead of one, four distinct and permanent types
prevail. It was upon these four types that he based his four fundamental
branches of the animal kingdom: Vertebrata, Articulata, Mollusca and
Zoopliyta or Eadiata.

A comparison of this classification with that of Linnaeus will show
what a tremendous advance had been made in the development of the sys-
tem in the half-century separating them. The group of animals which
had benefited most in this general advance was probably the Mollusca,
which was Cuvier's special field of research. The lowest group in Cuvier's
system, as in that of Linnaaus, was the one about which the least was
known, the Zoophyta or Eadiata, being made up of several distinct and
heterogeneous groups of animals which bore no near relationships to one
another.

This condition led to an active investigation during the generation
immediately following of all the lower animals, and a very large number
of works of fundamental importance appeared. Rudolphi studied the
parasitic worms, Tiedemann and L. Agassiz the anatomy and Johannes
Miiller the development of echinoderms, Ehrenberg the microscopic ani-
mals, Eschscholtz, Sars, and others jellyfish and polyps. The knowledge
of these two latter groups was also very much extended as the result of
various scientific expeditions which were sent out by the French, English,
Russian, and American governments to different parts of the world, espe-
cially to the tropical oceans. Of these voyages perhaps the most inter-
esting were that of the Russian ship Eurik from 1815 to 1818 in which
Chamisso and Eschscholtz went as naturalists and discovered the alterna-
tion of generations of Salpa, that of the English ship Beagle between 1831

4 INTRODUCTION

and 1835 with Darwin as naturalist, and the American expedition under
Captain Wilkes between 1838 and 1842 with James Dwight Dana as the
principal naturalist.

The influence of all these investigations, and also that of the newly
established cellular theory of the structure of plants and animals, on the
development of the zoological system, led to the third great reform of the
latter. In 1845 von Siebold subdivided Cuvier*s fourth type, the Zoophyta
or Radiata, into three types or phyla, the Protozoa, Zoophyta, and Vermes,
confining thus the term Zoophyta to the truly radiate animals. He also
broke up Cuvier*s second type Articulata, removing the Annelida to the
new phylum Vermes and creating another new phylum for the Crustacea,
Arachnida, Myriapoda, and Insecta which he called the Arthropoda. Two
years later R. Leuckart broke up the phylum Zoophyta, subdividing it
into the phyla Echinodermata and Coelenterata, and emphasized the iso-
lated position of the Protozoa. Milne-Edwards also formed still another
new type or phylum, the Molluscoidea, in which he included the Bryozoa
and Tunicata. The animal kingdom was thus in 1850 subdivided into
eight phyla, the Protozoa, Ccelenterata, Echinodermata, Vermes, Arthro-
poda, Molluscoidea, Mollusca, and Vertebrata, an arrangement which is
still found in many textbooks.

Darwin's Origin of Species was published in 1859 and the fourth
and last important reform of the zoological system of classification was the
direct consequence of the doctrines therein promulgated. The theory of
the common descent and blood relationship of all animals which Darwin
taught was at variance with Cuvier*s theory of fixed types and in harmony
with Lamarck's theory of the essential unity of the animal kingdom, 'and
was first employed by Haeckel as the basis of a system of classification.
In 1877 he called attention to the need of placing the entire system on an
evolutionary basis and at the same time subdivided the animal kingdom
into the two great groups of the Protozoa and the Metazoa, and the
latter into the two great groups of the Coslenterata and the Ccelomata. In
still more recent times other authors, notably Hatschek, following HaeckePs
lead, have carried the subdivision still further on the same basis. The old
idea of types, however, has a very tenacious life and is still the basis of
the classification of animals in most textbooks— and probably rightly so.
For animals can, as a matter of fact, notwithstanding their ultimate
relationships with one another, be grouped in a number of distinct types
or phyla, each of which has a characteristic plan of structure. Cuvier's
belief, however, that these types are fixed and isolated creations has long
since been abandoned.

Very important has been the formation in recent times of the phylum,
Chordonia or Chordata, which brings under the same subdivision all the

INTRODUCTION 5

animals possessing the essential characteristics of the vertebrate type.
The formation of this phylum has been due to the fundamental researches
of Kowalevsky, who in 1866, 1867, and 1871 gave the first detailed and
accurate descriptions of the anatomy of Balanoglossus and also the first
detailed account of the embryology of ascidians and of Amphioxus, show-
ing that these animals are related to one another and to vertebrates. The
term Chordonia was introduced in 1874 by Haeckel to include the Tuni-
cata, Amphioxus, and the Vertebrata, and the terms Urochorda and
Cephalochorda by Lankester in 1878 for the Tunicata and Amphioxus.
In 1884 Bateson, on the basis of his researches on the American form
Balanoglossus aurantiacus, added the Enteropneusta to the Chordata and
proposed the term Hemichorda.

The system of zoological classification was thus fixed some twenty or
thirty years ago and has undergone no important changes in its larger
features since. This is not true, however, of many of the subordinate and
smaller of its groups, the arrangement of which changes from time to
time as the knowledge of the relationships of the animals composing them
increases. We find this to be especially true of certain low animals
which seem to be isolated side branches of the ancestral tree, the origin
of which from the main stem is still obscure.

2. The study of animals in America.* —The earliest notices of Amer-
ican animals are to be found in the numerous descriptions of the country
and books of travel in America which were published in Europe during
the sixteenth, seventeenth, and eighteenth centuries. In Linnaeus' twelfth
edition over 500 species of North American animals were described, of
which 78 were mammals and 260 were birds. Of the authors quoted
in these descriptions perhaps the most important were Mark Catesby and
Peter Kalm. The former was an Englishman who lived in the southern
English colonies of America for about ten years between 1712 and 1726
and published a large illustrated work on the natural history of the
region. The latter was one of Linnaeus' pupils who spent the years
between 1747 and 1751 in Canada and the central English colonies col-
lecting and studying the native animals and plants for him. Linnaeus
also obtained much information by correspondence with American nat-
uralists, especially Dr. Alexander Garden of Charleston, Dr. John Mitchell
of Virginia, and John Bartram of Philadelphia. Thus in 1766 probably
most of the larger and more conspicuous animals of the eastern part of
the country were known to science, as well as many insects and other
smaller ones.

* See "A Century's Progress in American Zoology," by A. S. Packard, Jr., Am.
Nat. Vol. 10, p. 591, 1876. "The Beginnings of American Science," by G. B. Goode,
Ann. Rep. Smiths. Inst. for 1897, Pt. 2, p. 409.

6 INTRODUCTION

Important among the native authors of the period immediately follow-
ing the Revolution were Thomas Jefferson, who has the distinction of
being the only American President besides Theodore Roosevelt who has
been interested in scientific pursuits, Benjamin Smith Barton, and William
Bartram, the son of John, both of Philadelphia.

One of the first general works of importance on American animals
was Wilson's Ornithology (1808-1814). Other similar works belonging to
nearly the same period were Bonaparte's continuation of Wilson's
Ornithology (1825-1833), Dr. Richard Harlan's Fauna Americana (1825),
Dr. John D. Godman's American Natural History (1826-1828), which was
specially devoted to Mammals, and Audubon's Birds of North America
(1828).

During the second and third decades of the century occurred a
remarkable scientific awakening in the country, 'an evidence of which was
the publication of so many works of general interest during this time
and also the foundation of a large number of scientific societies and
periodicals. At the beginning of the century there were three promi-
nent scientific societies in the country, the American Philosophical Society,
which was founded in Philadelphia in 1743 by Benjamin Franklin, the
American Academy of Arts and Sciences, founded in Boston in 1780 by
John Adams, and the Connecticut Academy of Arts and Sciences, which
was founded in New Haven in 1799. During the first quarter of the
century many others were founded in various parts of the country,
and in 1826 no fewer than twenty-five scientific societies were in exist-
ence, more than half of which were interested principally in natural
history.

In 1812 the Philadelphia Academy of Natural Sciences was founded,
and exercised an important influence from the start. The first volume of
its journal appeared in 1817. Its importance in the first years of its
existence was due largely to the labors of a single one of its members,
Thomas Say. This talented young man joined the Academy shortly after
its foundation and for twelve years, under its auspices, devoted himself
exclusively to the study of the native animals, the papers he contributed
to its journal and to other periodicals during this period being funda-
mental for the study of American mollusks, insects, and crustaceans.
Another brilliant member of the Academy during this period was Charles
Alexander Lesueur, a Frenchman who joined it in 1817 and, during the
seven years that he was a resident of Philadelphia, published many papers
in its journal on fishes, reptiles, and marine invertebrates.

Belonging to the same period was another remarkable man, Constan-
tine Rafinesque. This brilliant and versatile man came to this country
in 1802 and lived for many years in Philadelphia and in Lexington,

INTRODUCTION 7

Kentucky. He was a pioneer botanist and zoologist and is now remem-
bered by the large number of new species of mollusks and of fishes, as
well as of plants, which he described. He is also remarkable as being the
first American who clearly enunciated the principle of the transformation
of species.

Philadelphia was during this period the most important scientific
center of the country, but it was not the only one. The interest in natural
history was widespread and every city had its public museum of natural
curiosities and its scientific society. The Philadelphia Museum, which was
established by Charles Wilson Peale, and the Baltimore Museum estab-
lished by Rembrandt Peale were especially famous. In the South the
eminent Georgian Dr. Lewis Le Conte, father of Professor Joseph Le
Conte, and Stephen Elliott of Charleston were prominent as naturalists,
and in the west Dr. Robert Best had founded the Western Museum in
Cincinnati and given the initial impulse to those scientific activities which
have ever since distinguished that city.

In New England the principal scientific interest was in geology and
mineralogy. The most influential scientist was Benjamin Silliman of
New Haven, a geologist and a chemist. In 1818 he founded the American
Journal of Science and Art which at once became and has since remained
one of the most influential in the country.

The fourth and most of the fifth decades were not a period of marked
activity in the study of American animals. The remarkable development
of the zoological and physiological sciences in Europe under the leader-
ship of von Baer, Johannes Miiller, Owen, Milne-Edwards and others
apparently awakened little interest on this side of the Atlantic and the
most important investigators were chiefly occupied with descriptions of
shells and insects. In 1838, however, occurred an event important to
the development of American science, for in that year the United States
Exploring Expedition under Captain Wilkes started on its four years7
voyage, taking as one of its naturalists James Dwight Dana.

It was in 1846 that light at length began to appear in the general
darkness and the way to be prepared for the important advances of later
years in the field of natural science, for in this year the Smithsonian
Institution, which was to become the center of most important scientific
activities, was founded under the secretaryship of Joseph Henry, and in
this year also Louis Agassiz came to America.

The modern study of animals in America may be said to begin with
the arrival of Agassiz on our shores. His great reputation and attractive
and inspiring personality brought him at once into prominence and drew
to him a large number of brilliant young men who wished to study animals
under his leadership, and Cambridge and Boston soon became the most

8 INTRODUCTION

important center of zoological investigation in the country. Agassiz ele-
vated these studies to a much higher plane than they had occupied by
placing them in close touch with European scholarship and also by broad-
ening and extending them by the introduction of comparative embryology
and physiology. He also founded and built up the first great zoological
museum in the country.

The Cambridge school did not, however, contain all the zoologists in
the country. In 1846 James Dwight Dana, who had become a Professor
in Yale and is now remembered rather as a geologist and a mineralogist,
published his Report on the Zoophytes, and in 1852 his Report on the
Crustacea of the Wilkes Expedition, both epoch-making zoological works
and the most extensive works of a monographic nature which up to that
time had been published by an American. In 1854 appeared the remainder
of his report on the zoology of this Expedition. Joseph Leidy also, in
Philadelphia, was beginning his brilliant studies of parasitic worms and
other small animals.

The study of shells was followed assiduously in this country during
this period. Dr. A. A. Gould of Boston, who published the Report of
the Hollusks of the Wilkes Expedition and also the Invertebrata of
Massachusetts, Isaac Lea of Philadelphia and A. and W. G. Binney being
among the most important of the many authors. The study of insects
was likewise making important advances and T. W. Harris produced his
Forest Insects, one of the earliest works on economic entomology.

The most important zoological work of the sixth, seventh, and eighth
decades of the century was undoubtedly the study of the marine animals
of our coast by Louis Agassiz and his pupils and followers, of whom
James McCrady, William Stimpson, Theodore Lyman, Alexander Agassiz,
Alpheus Hyatt, H. J. Clark, and A. E. Verrill are particularly to be
mentioned. During the same period J. L. Le Conte, Samuel Scudder,
C. V. Riley, and A. S. Packard were engaged in the study of insects and
in laying the foundation of the influential American school of systematic
and economic entomology, and J. H. Comstock established the department
of entomology at Cornell which has become a leading factor in the devel-
opment of the science in this country. Vertebrates were also being
studied assiduously by E. D. Cope, who in the study of fishes, amphib-
ians, reptiles, and mammals, and by S. F. Baird and Elliott Coues,
who, in that of birds and mammals, all produced work of fundamental
importance.

In December, 1873, Louis Agassiz died and with his death ended an
important era in the history of American zoology— but only to give way
to another more important. The distinctive school of zoological investi-
gation which he founded continued to flourish, not only in Cambridge

INTRODUCTION 9

Under the leadership of Alexander Agassiz and E. L. Mark, but 'also in
Baltimore where Louis Agassiz's pupil W. K. Brooks taught in the newly
founded Johns Hopkins University. From these two centers the scientific
study of animals has spread to almost all the universities and other institu-
tions of learning of the country, and the men who have gone out from them
all year by year in ever increasing numbers have maintained the high stand-
ards which Agassiz represented and have today placed American scholar-
ship in this field in the fore rank of the world's achievement.

Very important in the history of American zoology was the estab-
lishment, a few years after the death of Louis Agassiz, of the Woods
Hole Marine Biological Laboratory (1887), The Journal of Morphology
(1888), and the Morphological Society (1890). These enterprises were
due very largely to the initiative of C. 0. Whitman and brought about a
solidarity of interest of the scientific zoologists of the country to which
the great advances made by zoological investigation in America in recent
years and the high rank it has attained in the world are largely due.

Important also has been the part taken by the various scientific de-
partments of the United States government in furthering the study of
animals. This work was begun by the Smithsonian Institution in 1846
and has been continued directly by it and the United States National
Museum, the Bureau of Fisheries, the Geological and Coast Surveys, the
Marine Hospital, and the various Bureaus in the Department of Agri-
culture. The important scientific work carried on by these institutions
and the great collections they have accumulated have made Washington
today the most important scientific center in the country.

3. Subdivisions of the animal kingdom.— The animal kingdom con-
tains in this book eight subkingdoms or phyla. Several of these are sub-
divided into subphyla, and all the phyla and subphyla into classes. The
classes are made up of orders, although they are sometimes first sub-
divided into subclasses and these into orders. The orders, and the sub-
orders into which some of them are subdivided, are made up of families,
and often subfamilies. Each family and subfamily is composed of one
or more genera and each genus of one or more species. The combination
of its generic with its specific name constitutes the scientific name of an
animal.

The whole number of species of animals* which make up the animal
kingdom is not known but probably amounts to several million. The
number which has been described in scientific publications and given
names in the Linna3an system of classification is considerably over half
a million.

* See "On the Number of Known Species of Animals," by H. S. Pratt, Science,
N. S., Vol. 35, p. 467, 3912.

10 INTRODUCTION

The following estimates have been made of the number of the
described species in each phylum:

Phylum I. Protozoa 8,000

Phylum II. Coelenterata 7,000

Phylum III. Vermes 9,000

Phylum IV. Annelida 4,000

Phylum V. Arthropoda 400,000

Phylum VI. Mollusca 61,000

Phylum VII. Echinodermata 4,000

Phylum VIII. Chordata 37,000

Key to the phyla of the Animal Kingdom :

Oi Single-celled animals, aquatic and microscopic 1. PROTOZOA

a2 Many-celled animals.
&! Body radially symmetrical.

ct Body with 2, 4, 6 or more, or without, definite radii 2. CCELENTERATA

c2 Body with 5 radii 7. ECHINODERMATA

&2 Body bilaterally symmetrical.
ct Respiratory organs not pharyngeal.
dj Body without a calcareous shell (with rare exceptions).

ev Body not externally segmented (except in tapeworms) 3. VERMES

ej Body externally segmented.

f, No segmented locomotory appendages 4. ANNELIDA

/2 Paired segmented appendages present 5. ARTHROPODA

<Li Body with a calcareous shell 6. MOLLUSCA

ca Respiratory organs internal and pharyngeal 8. CHORDATA

PHYLUM I.

PROTOZOA.* (SINGLE-CELLED ANIMALS.)

The Protozoa are minute, aquatic animals which consist each of a single
cell. The body, like any other animal cell, is a mass of protoplasm con-
taining one or more nuclei. Distinct organs, in the ordinary sense, are not
present, but certain specialized structures are usually found in the body
which perform certain special functions. The Protozoa perform all the

Fig. 1 Fig. 2

Fig. 1 — Amoeba Umax (Conn). Fig. 2 — Amceba proteus (Conn); cv, contractile

vacuole; ec, ectosarc; en, entosarc; ex, excreta; n, nucleus;

p, pseudopodium.

essential functions which characterize the 'animal body. The superficial
layer of the protoplasmic body is usually hyaline and distinct and is called
the ectosarc (Fig. 2). It secretes in most forms a cuticula or even a hard
shell which gives the body definite form. In the simplest cases, locomotion
is accomplished by the thrusting out of projections called pseudopodia
(Fig. 2) in the direction of movement. In the highest forms, however, cilia

* See "Protozoa," by O. Biitschli. Bronn's "Klassen u. Ord. des Thierreichs,"
Vol. I, 1880-1889. "A List of the Protozoa and Rotifers Found in the Illinois River,"
etc., by A. Hempel, Bull. 111. St. Lab., Vol. 5, p. 301, 1898. "A Report on the Pro-
tozoa of Lake Erie," etc., by H. S. Jennings, Bull. U. S. Fish. Com., 1899, p. 105.
"The Protozoa," by G. N. Calkins, 1901. "Marine Protozoa of Woods Hole," by same,
Bull. U. S. Fish. Com., 1901, p. 413. "The Protozoa of the Fresh Waters of
Connecticut," by H. W. Conn, Bull. No. 2, State Geol. and Nat. Hist. Survey. "The
Protozoa of Iowa," by C. H. Edmondson, Proc. Acad. Sci., Davenport, 1906. "The
Protozoa of Sandusky Bay," by F. L. Landacre, Proc. Ohio St. Acad. Sci., Vol. 4,
p. 421, 1908 (containing a full bibliography). "Protozoology," by G. N. Calkins,
1909, "Lehrbuch der Protozoenkunde," by F. Doflein, 3d Ed., 1911. "The Protozoan
Parasites of Domestic Animals," by H. Crawley, Circ. 194, Bur. An. Ind., Dep. of
Ag., 1912.

11

12 PEOTOZOA

(Fig. 87) or flagella (Fig. 35), which are projections of the ectosarc, are
present and are permanent organs of locomotion. In a few ciliates true
muscle fibres are present. Sensation is exercised by the entire surface of
the body and its projections.

The inner portion of the body is called the entosarc (Fig. 2) ; in it
nutrition is carried on. Food in solid form may be taken into the mass of
the entosarc, where it is usually surrounded by a watery fluid forming the
food-vacuole, and digested and absorbed. In the lower Protozoa the food
particles are taken in through the outer surface by a simple process of
engulfing, no mouth being present, but in most Infusoria a definite mouth
is present in the ectosare from which a gullet leads into the entosarc.
Indigestible portions of the food are thrown out through an anal opening
in the ectosarc which in the higher forms alone is a permanent structure.
Many protozoans lead parasitic lives and absorb the vital fluids of their
hosts through the outer surface of the body. Great numbers of the flagel-
lates also closely resemble plants in their habits of nutrition. Respiration
is carried on through the entire outer surface of the body, as is also
excretion in most marine and parasitic Protozoa. In the majority of
Protozoa, however, a special excretory organ, the contractile or pulsating
vacuole (Fig. 2, cv), is present in the form of a minute globule of clear,
excretory fluid which collects periodically and is then discharged to the
outside through a temporary opening in the ectosarc. The contractile
vacuole probably exercises a respiratory as well as an excretory function,
carbon-dioxide being eliminated by its discharges.

The characteristic method of reproduction is by equal division. The
nucleus takes the lead in the process and is quickly followed by the body
of the cell, and two new individuals are thus formed from a single old
one. In many Protozoa the new individuals are not completely separated
from each other, but remain connected together, and a colony is thus
formed, while in some a physiological division of labor occurs among the
members of such a colony and an important step towards the development
of a metazoan animal is taken. Still another modification of simple
division is the formation of spores, which characterize the Sporozoa and
occur occasionally in the other Protozoa. Spore formation may be pre-
ceded by the encystment of the animal and a period of rest; the animal
draws itself together into as small a compass as possible and then secretes
a firm membrane or shell within which it lies while spore formation is
being accomplished. Later the cyst breaks and the spores being liberated
each becomes a new individual.

Of universal occurrence among Protozoa is conjugation, or the tem-
porary or permanent fusion of individuals, which in some of its phases
resembles the process of fertilization in the higher animals. The two

DESCRIPTION AND HISTORY 13

individuals which conjugate may be either (1) similar full-sized animals,
(2) full-grown animals of dissimilar size, (3) reduced individuals of similar
size (similar swarm-spores), or (4) reduced individuals of dissimilar size
(specialized gametes). In the last mentioned case the gametes resemble
the male and female reproductive cells of the Metazoa.

Conjugation was formerly thought to be a process of rejuvenation by
which the vital energies of the animals are renewed after the appearance
of senile changes and a decrease in size and strength. It is now believed
to be rather a method for the introduction of variation into a race or
species, and to have thus a meaning similar to that of sexual reproduction
among the Metazoa, a variable race being better fitted to adapt itself
to a changing environment and to overcome unfavorable life-conditions.

The Protozoa are all, with a few exceptions, aquatic animals. When
the water in which they are living dries up and at certain other times
they encyst themselves, and in this condition can withstand complete
desiccation a long time. Protozoa are easily transported by the wind,
especially when encysted, and many species have a world-wide distri-
bution.

Protozoa feed upon organic matter in every form. Certain species
are carnivorous ; others feed exclusively on plants ; many feed on decaying
substances; and many are parasitic. Of this latter kind many, especially
among the Sporozoa, are the cause of disease both in man and animals.
Many contain chlorophyll and live like plants and are consequently near
the border line between plants and animals.

History.— Microscopic animals were first studied in 1675 by the Dutch
naturalist Leeuwenhoek, who first used the microscope in the study of living
organisms. About a hundred years later Otto Friedrich Miiller described
a large number of them, adopting the binomial nomenclature, and thus
laid the foundation of the present classification. The name Protozoa
originated with Goldfuss in 1820, who, however, included in the group
jellyfish, liydroids, and all of the lowest animals. In 1838 Ehrenberg
published his epoch-making work on Infusoria, including in this term all
the microscopic animals, the significance of his work consisting in the fact
that he brought together accurate descriptions of great numbers of these
organisms. Ehrenberg was followed by Dujardin and others and in
1845 von Siebold, interpreting these simple creatures in the light of the
newly established cell-theory, separated them from the Radiata, with
which they were classed, and applied to them the name Protozoa.
Biitschli (1880-1889) gave the classification of the group its present
form.

The Protozoa contain 4 classes and about 8,000 species, of which the
majority are radiolarians.

14 PROTOZOA

Key to the classes of Protozoa:
«! Cilia or flagella absent.
6X Pseudopodia present, sometimes with rigid, axial filaments ... 1. SARCODINA

62 Pseudopodia absent, as well as all other locomotory organs, in the adult

animal 3. SPOEOZOA

a2 Cilia or sucking tentacles, or flagella present.
6X Flagella present 2. MASTIGOPHOBA (Flagella ta)

63 Cilia or sucking tentacles present 4. INFUSORIA

CLASS 1. SARCODINA.*

The most primitive Protozoa, in which the body is usually with-
out definite form, but in most cases possesses rigid skeletal structures.
Locomotion is effected by means of pseudopodia, which are more or less
temporary projections of the body. In the Heliozoa and Radiolaria these
are much less changeable in form than in the Rhizopoda and are usually
supported by a central skeletal filament. Contractile vacuoles are present
except in the marine forms. Encystment and conjugation characterize all.
The majority of the Sarcodina are marine animals and they are often
present in such large numbers in the sea that the empty shells form
important deposits at the bottom (Foraminifera) . The affinities of the
Sarcodina are with the flagellates : the young of certain forms are flagellate
and in Mastigamceba and others the adult form has both pseudopodia and
flagella. The class was first called the RMzopoda, but in 1880 Biitschli
substituted the term Sarcodina for Rhizopoda, giving the latter name to one
of the orders. The class contains 6,000 species, most of which are
Radiolaria and Foraminifera, grouped in 3 orders.

Key to the orders of Sarcodina:

»! No central capsule present ; animals in both salt and fresh water.

61 Body naked or with shell, with very changeable pseudopodia which contain

no central axial filament 1. RHIZOPODA

62 Body naked or with shell, usually of spherical and relatively permanent form

with delicate ray-like pseudopodia, each of which contains a central

filament 2. HELIOZOA

aa Central capsule present ; marine animals of relatively permanent form with
ray-like pseudopodia 3. RADIOLAEIA

ORDER 1. RHIZOPODA.

Body usually covered externally by a shell (but sometimes without)
which is a secretion of the ectosarc, and in many cases is covered with
sand or other foreign objects; pseudopodia variable in form: 2 suborders
and about 1,500 species, of which 200 live in fresh and 1,300 in salt water.

Key to the suborders of Rhizopoda:

«! Rhizopoda with simple pseudopodia and with or without a shell. .1. AMCEBIDA
o2 Rhizopoda with branching and anastomosing pseudopodia and with or without

a shell 2. RETICULARIIDA

* See "Freshwater Rhizopoda of North America," by J. Leidy, Rep. U. S. Geol.
Sur., etc., Vol. 12, 1879.

RHIZOPODA 15

SUBORDER 1. AMCEBIDA.

Rhizopoda having lobose pseudopodia which may be finger-shaped or
pointed, but are usually not reticulate; shell of chitin or silica usually
present, to which sand or other foreign bodies may be attached : 3 families.

Key to the families of Amoebida:

ax Naked Amcebida 1. AMCEBIDAE

a2 Amoebida with a shell.
&! Shell membranous, often with sand and other foreign bodies imbedded in

it 2. ABCELLIDAE

&2 Shell composed of regular plates of silica or chitin ; pseudopodia sharp and
often branching and sometimes slightly anastomosing .... 3. EUGLYPHIDAE

FAMILY 1. AMCEBIDAE.

Shell-less Rhizopoda, whose pseudopodia are not reticulate; body
without definite form and under ordinary conditions constantly changing
its shape by throwing out pseudopodia, although covered by a cuticula of
greater or less delicacy: about 19 genera, with numerous species in both
fresh and salt water.

Key to the genera of Amoebidae here described :

0,1 Nucleus absent 1. PROTAMCEBA

a2 Nucleus present and usually distinct.

&x Numerous nuclei, vacuoles, and retractile bodies present 2. PELOMYXA

62 Numerous nuclei, vacuoles, and retractile bodies not present.

cx Pseudopodia membrane-like, ectosarc reddish 3. PLAKOPUS

c2 Pseudopodia not membrane-like.
d: Pseudopodia more or less lobose, sometimes slender and spine-like.

et Animals not parasitic 4. AMCEBA

e2 Animals parasitic 5. ENTAMCEBA

d2 Pseudopodia very long, radiating spine-like from body.

6. DACTYLOSPH^EBIUM

1. PROTAMCEBA Haeckel. Minute forms without nucleus or con-
tractile vacuole, in constant motion, with short pseudopodia: 4 species;
in salt and fresh water.

P. primitiva Haeckel. In fresh and salt water.

2. PELOMYXA Greeff. Very large forms constantly flowing by
means of short pseudopodia; body with numerous nuclei, vacuoles and
hyaline rods ; diameter up to 2 mm. : 4 species ; in fresh water.

P. palustris Greeff. Without projections at hinder end.

P. villosa Leidy. Possesses numerous posterior projections; about
1 mm. in length; body dark and opaque.

P. carolinensis H. V. Wilson. No rods present, but numerous
minute crystals; 1 mm. in diameter.

3. PLAKOPUS F. E. Schulze. Body changes slowly in form and with
pointed pseudopodia which are often joined together by a broad mem-
brane: 2 species; in fresh water.

16 PROTOZOA

P. ruber F. E. Schulze. Color reddish : in fresh water.

4. AMCEBA Ehrenberg. Body may assume a variety of forms, being
often more or less spherical while at rest ; pseudopodia either slender or
lobose; nucleus and contractile vacuole present: about 12 species; in
fresh and salt water.

A. Umax Dujardin (Fig. 1). Body small, elongate, without
definite pseudopodia and moves by slowly flowing along: in fresh
water.

A. proteus (Pallas) (Fig. 2). Diameter up to .5 mm.; pseudopodia
long and usually blunt ; movements often active : in fresh water.

A. radiosa Ehr. Pseudopodia slender and radiating; body more or
less star-shaped; diameter about .04 mm.: on water plants.

Fig. 3 Fig. 4 Fig. 5

Fig. 3 — Amoeba verrucosa (Conn). Fig. 4 — Entam&ba coli (Doflein).
Fig. 5 — Entamceba dysenteriae (Doflein).

A. verrucosa Ehr. (Fig. 3). Diameter up to .2 mm.; pseudopodia
short; surface folded; movements sluggish.

5. ENTAIKEBA Casagrandi and Barbagallo. Similar to Amoeba, but
parasitic in mammals; size minute; pseudopodia short and sluggish:
several species.

E. coli (Loesch) (Fig. 4). Form roundish or elongate with a dis-
tinct nucleus and an indistinct ectosarc; pseudopodia short and slug-
gish; diameter .06 mm.: in human colon; formerly supposed to be a
cause of dysentery.

E. dysenteriae (Councilman and Lafleur) (E. Jiistolytica Schaudinn)
(Fig. 5). Similar to E. coli but with a distinct ectosarc: in the human
colon; the cause of dysentery.

6. DACTYLOSPHJERITTM Hertwig and Lesser. Small round forms
with often numerous long.ray-like pseudopodia, which sometimes vibrate
slightly; short and blunt pseudopodia also present when the animal
moves: in fresh water.

D. radiosum (Ehrenberg). Three or 4 long spine-like pseudopodia;
diameter .02 mm.

D. polypodia F. E. Schulze. Numerous finger-like pseudopodia
present.

RHIZOPODA 17

FAMILY 2. ARCELLIDAE.

Shell membranous and consisting of a single chamber, the surface
of which is either smooth or covered with sand or other foreign par-
ticles; single opening usually present from which blunt pseudopodia
protrude: fresh-water animals of minute size; 10 genera and about 30
species.

Key to the genera of Arcellidae here described :

«! Shell covered with sand or other foreign bodies 1. DIFFLUGIA

o. Shell not covered with foreign bodies.

&! Shell composed of quadrilateral plates 2. QUADBUELLA

6a Shell of one piece, not composed of plates.

cx Shell flexible and more or less disc-like ; 1 to 3 openings. .3. COCHLIOPODIUM
c. Shell disc-shaped and not flexible.

dj Rim of shell without spines 4. ARCELLA

d 2 Rim of shell with spines 5. CENTROPYXIS

1. DIFFLUGIA Leclerc. Shell covered with sand-grains or other
foreign bodies, pear-shaped or spherical, frequently with spines at the
sides or hinder end, and with a large opening at the other end from

Fig. 6 Fig. 7 Fig. 8

Fig. 6— Difflugia lobostoma (Conn). Fig. 7— Difflugia corona (Leidy).
Fig. 8 — Quadruella symmetrica (Leidy). ^

which a number of blunt pseudopodia may project; nucleus and con-
tractile vacuoles always present: about 20 species, which are very vari-
able in form; in fresh-water pools, usually on plants or on the bottom.

D. lobostoma Leidy (Fig. 6). Shell spherical or ovate, the oral pole
truncated; mouth usually 3 to 6 lobed; aboral end rounded; length .12
mm. : common.

D. pyriformis Perty. Shell bottle-shaped with a cylindrical neck
more or less distinct ; length up to .6 mm. : common.

D. urceolata Carter. Shell jug-shaped with short neck and often a
rim; hinder end pointed or rounded; length up to .52 mm.

D. constricta Ehrenberg. Shell ovoid; mouth oblique; aboral end
rounded, often with spines; length up to .3 mm.

D. globulosa Dujardin. Shell spheroidal or oval; mouth circular;
length .2 mm. or less: rather common.

D. acuminata Ehr. Shell oval; aboral end acute, often prolonged,
rarely with 2 or 3 points; length ,4 mmr

18

PROTOZOA

D. corona Wallich (Fig. 7). Shell spheroid with a number of long
spines at hinder end; length up to .32 mm: very common.

2. QITADRTJELLA Cockerell. Shell
pear-shaped and composed of quad-
rilateral silicious plates, with oc-
casional spines at the hinder end:
several species ; in fresh water.
Q. symmetrica (F. E. Schulze)

(Fig. 8). Length up to .14 mm.:
Fig.Q—CochliopodiumWMosum (Leidy). • CWQTY1T,C

111 bWdlll^Jo*

3. COCHLIOPODITTM Hertwig and Lesser. Shell minute, spheroid or
disc-like, without foreign bodies, and flexible, changing in shape: 3
species; in fresh water.

C. bilimbosum Auerbach (Fig. 9). Diameter
up to .05 mm. ; opening large, the acute pseudopodia
protruding: among algae, etc., in fresh water.

C. digitatum Calkins. Several openings through
which pseudopodia protrude.

4. ARCELLA Ehrenberg. Shell yellow or brown
and smooth, not being covered with sand, convex
on one side, and flat or concave on the other, in
the middle of which is the opening; nuclei and
contractile vacuoles 2 or more: several species; in
fresh water, also in moist sand and moss.

Fig. 10

Arcella vulgaris

(Leidy). A, under

view of shell ;

B, side view.

A. vulgaris Ehr. (Fig. 10). Diameter about .15 mm.; margin not
scalloped: very common.

A. dentata Ehr. (Fig. 11). Diameter about .18 mm.; margin scal-
loped.

Fig. 11

Fig. 12
Fig. 13— Eugtypha a'lveolata (Leidy).

Fig. 13

Fig. 11 — Arcella dentata (Leidy). Fig. 12— C entropy xis aculeata (Leidy).

5. CENTROPYXIS Stein. Shell similar to Arcella, but with spines,
variable in number, and sometimes elongate: in ditches and pools.
C. aculeata Stein (Fig. 12). Diameter of shell .2 mm.

EHIZOPODA 19

FAMILY 3. EUGLYPHIDAE.

Shell membranous and composed of plates of chitin or silica
enclosing a single chamber with a single large opening; pseudopodia
filiform and sometimes somewhat anastomosing; size minute: 5 genera;
mostly in fresh water.

1. EUGLYPHA Dujardin. Shell elongate, ovate, often with spines
at hinder end and composed of oblique rows of round plates whose
edges overlap, making hexagonal areas; opening denticulate; pseudo-
podia fine, often branching but not reticulate: in fresh water; 4
species.

E. alveolata Duj. (Fig. 13). Shell colorless, elongated
and cylindrical; hinder end broader, usually with a few
long spines ; plates composing it are round or oval ; length
.15 mm.: common.

E. ciliata Leidy. Shell elongate and elliptical in
cross section; hinder end and sides with numerous short
spines; plates six-sided; length .1 mm.: common in
sphagnum moss.

2. CYPHODERIA Schlumberger. Shell retort-shaped

and composed of minute plates; opening turned to one Fig~l4
side; forward half of body contains numerous contractile Cyphoderia
vacuoles, and hinder half the nucleus; color yellowish: (Leidy).
2 species; in fresh and salt water.

C. ampulla (Ehrenberg) (Fig. 14). Length .17 mm.: in ponds and
ditches.

SUBORDER 2. RETICULARIIDA.

Pseudopodia filiform and reticulate; calcareous shell usually pres-
ent which has either one or more large openings or many minute ones,
through which the pseudopodia project: 3 divisions.

Key to the divisions of Eeticulariida :

ox No shell present 1. NUDA

o2 Shell with one or more large and no minute openings 2. IMPEBFOBINA

os No large but numerous minute openings 3. PEKFOBINA

DIVISION 1. NUDA.

Rhizopods without shell and with reticulate pseudopodia: about 8
genera; mostly marine.

BIOMYXA Leidy. Form incessantly changing; nucleus present or
apparently absent: 1 species.

B. vagans Leidy. Color pale gray with oil globules, nucleus when
present large and distinct; no ectosarc: in sphagnum moss.

20 PROTOZOA

DIVISION 2. IMPEEFORINA.

Rhizopods with shell which has one or more large openings from
which project reticulate and anastomosing pseudopodia; shell usually
calcareous, but sometimes membranous, to which sand may adhere, and
one or many chambered: 4 families.

FAMILY GBOMIIDAE.

Marine and fresh-water rhizopods with a membranous shell with
an opening at one or both ends : 10 genera.

Key to the genera of Gromiidae here described:

Oi Shell with but one opening.
&! Pseudopodia richly anastomosing ; contractile vacuoles usually present.

1. GROMIA
62 Pseudopodia anastomosing little ; numerous contractile vacuoles.

2. PAMPHAGUS
ca Shell with an opening at each end 3. DIPLOPHBYS

\Vfe>;

\ mm^

m&'&cl-£i~

Sttwj

&:y~- .; ....-•

•:-:^Sf K' JSsJL

....... -$Z5%-

t~*.i~"" "

^r^:;^:;

Tfty&jJyyp*

•••*'•/ • */*

Fig. 15 — Gromia lagenoides (Calkins).

1. GROMIA Dujardin. Shell spherical or ovate in shape and entirely
filled by the protoplasmic body; shell membranous and often flexible,
changing its shape; pseudopodia very fine and reticulate; nuclei one or
many : several species ; in fresh and salt water.

G. lagenoides Gruber (Fig. 15). Body about .25 mm. long, with
opening at larger end of shell; edge of opening turned in; a fine layer
of protoplasm surrounds the shell which has fine reticulate pseudopodia
on all sides of it; shell either with or without foreign bodies: Woods
Hole; not numerous.

2. PAMPHAGTJS Bailey. Pseudopodia very delicate, springing from
a common protoplasmic base and not anastomosing; shell flexible and
delicate, and filled by the protoplasmic body; opening of shell narrow:
7 species.

HELIOZOA 21

P. mutabilis Bailey. Body compressed and ovate or pear-shaped;
protoplasm yellowish in color ; length 1 mm. : in swamps.

P. hyalinus Leidy. Body almost spherical with short neck; often
colonial; length .04 mm.

3. DIPLOPHRYS Barker. Shell spherical and membranous and with
two openings opposite each other, from which protrude the pseudopodia :
2 species; in fresh water.

D. archeri Barker. Pseudopodia not always anastomosing; length
.02 mm.

DIVISION 3. PERFORINA. (FORAMINIFERA.)

Calcareous shell, either one or many chambered, and with numerous
minute pores, as well in some cases as large openings, through which
stream reticulate pseudopodia: 9 families with numerous genera and
over 1,200 species, most of which live in the mud of the sea bottom, about
20 species being pelagic.

FAMILY GLOBIGEBINIDAE.

Shell calcareous and one or many chambered with one or more large
openings: about 7 genera.

GLOBIGERINA D'Orbigny. Shell with many chambers which are
more or less ovoid and spirally arranged; large openings crescentic;
usually with spines: about 13 species; marine.

G. bulloides D'Orb. Animals pelagic and also in the bottom mud
at all depths down to 3,000 fathoms: cosmopolitan.

ORDER 2. HELIOZOA.*

Sarcodina with little power of amoeboid movement, with a silicious
skeleton and fine ray-like pseudopodia which are often supported by
silicious axial filaments; ectosarc and entosarc usually sharply marked;
contractile vacuole present in the fresh-water forms, but absent in the
marine ones; either one or several nuclei present; reproduction either
by equal division or by spore formation, the spores being flagellate
and after an active life losing their flagella and assuming the form of
the adult; conjugation and encystment also occur: about 50 species,
grouped in 4 suborders; mostly in fresh water, but also in the sea and
in moist earth.

Key to the suborders of Heliozoa:
at Heliozoa without skeleton.

&! Body naked 1. APHROTHOBACIDA

62 Body with a soft gelatinous or felted fibrous covering. .2. CHLAMYDOPHORIDA
«2 Heliozoa with skeleton.

&i Skeleton consists of spicules 3. CHALARATHOBACIDA

Z>2 Skeleton consists of a single piece perforated by numerous openings.

4. DESMOTHOP.ACIDA
* See "Heliozoa," by F. Schaudinn, Das Tierreich, 1896.

22

PEOTOZOA

SUBORDER 1. APHROTHORACIDA.

Naked Heliozoa with filiform pseudopodia radiating from all sides
which are either with or without axial filaments; one or more nuclei
and contractile vacuoles present: 9 genera.

Key to the genera of Aphrothoracida here described :

«i Body more or less amoeboid.
&! Ectosarc and entosarc sharply defined ; animals appear on algae as red

cysts 1. VAMPYRELLA

Z>2 No boundary between ectosarc and entosarc 2. NUCLEABIA

aa Body not amoeboid ; form spherical.
&! Ectosarc and entosarc not defined ; skeletal axis of pseudopodia extending to

center 3. ACTINOPHKYS

Z>2 Ectosarc and entosarc sharply separated 4. ACTINOSPH^EBIUM

Fig. 16

Fig. 17

Fig. 18

Fig. 16— Vampyrella lateritia (Leidy). Fig. 17— Actinophrys sol (Leidy).
Fig. 18 — Actinosphcerium eichhorni (Leidy).

1. VAMPYRELLA Cienkowsky. Ectosarc hyaline; entosarc brown or
red, frequently vaeuolated; form amoeboid, pseudopodia radiating from
all sides or arising from only one place: 5 species; in fresh and salt
water.

V. lateritia Leidy (Fig. 16). Body spherical or elongated; diameter
about .06 mm. ; length of moving animals may be .24 mm. : among fresh-
water algae.

2. NUCLEARIA Cienkowsky. Body spherical or elongate and amoe-
boid with homogeneous protoplasm; pseudopodia radiating from all sides
or arising from only one place ; one or more nuclei and many contractile
vacuoles: 2 species; in fresh water.

N. simplex Cienk. Diameter about .05 mm.: among Spirogyra and
other fresh-water plants.

3. ACTINOPHRYS Ehrenberg. Body spherical and not amoeboid;
pseudopodia radiating from all sides and with axial threads which
extend to center of body ; ectosarc and entosarc not separate : 1 species ;
in fresh and salt water.

A. sol (0. F. Miiller) (Fig. 17). Diameter .05 mm.; often colonial:
common.

HELIOZOA 23

4. AcTiNOSFH-ffiRiUM Stein. Like Actinophrys but with sharply
defined and vacuolated eetosarc: 1 species.

A. eichhorni (Ehrenberg) (Fig. 18). Diameter up to 1 mm.: in
fresh water; common.

SUBORDER 2. CHLAMYDOPHORIDA.

Body spherical and with a soft gelatinous or felted covering in
which foreign bodies may be present: 5 genera.

HETEROPHRYS Archer. Body with a slight differentiation into
eetosarc and entosarc; pseudopodia radiating from all sides: 2 species;
in fresh and salt water.

H. myriapoda Archer. Diameter .08 mm.; pseudopodia twice as
long as diameter of body; chlorophyll bodies often present: in fresh
and salt water.

SUBORDER 3. CHALARATHORACIDA.

Isolated silicious needles present which cover the outer surface: 8
genera.

1. RAPHIDIOPHRYS Archer. Body spherical, covered with silicious
needles lying tangentially ; eetosarc and entosarc not distinct; pseudo-
podia with axial threads radiating from all sides ; often forming colonies
which have a common covering: 4 species; in fresh water.

R. elegans Hertwig and Lesser. Diameter .04 mm.; often with
chlorophyll bodies : in fresh water.

2. ACANTHOCYSTIS Carter. Spherical animals in which the silicious
needles project radially; between them are the thread-like pseudopodia,
each with an axial thread; tangential needles may also be present: 10
species; in fresh water.

A. chsetophora (Schrank). Diameter .1 mm.; needles of 2 forms,
a short and a long, both forked, and both with basal plates.

SUBORDER 4. DESMOTHORACIDA.

Body enclosed in a silicious spherical shell containing numerous
round holes; a central nucleus; many contractile vacuoles and filiform
pseudopodia: 2 genera.

CLATHRULINA Cienkowsky. Body spherical and fastened by a stalk
to some fixed object; the body does not fill the shell, which is absent in
the young individuals : 2 species ; in fresh water.

C. elegans Cienk. (Fig. 19, p. 24). Diameter of shell .07 mm.; length
of stalk up to .3 mm.: in pools.

24 PROTOZOA

ORDER 3. RADIOLABJA.

Marine Sarcodina often of large size, with ray-like pseudopodia;
silicious skeleton present in most cases, which is often of great com-
plexity and beauty; pseudopodia usually with axial
filaments; body divided into two regions, the central
capsule and the extra-capsular portion; capsule sur-
rounded by a perforated chitinous membrane and oc-
cupying the center of the body containing also one or
more nuclei and often oil globules ; extra-capsular proto-
plasm often vacuolated and pigmented and containing
often yellow unicellular algae (zooxanthellae) which live
symbiotically in it; no contractile vacuole present; re-
production by division, the central capsule dividing first ;
in some forms the central capsule alone divides, and a
colony is the result; spore formation has also been ob-
served, in which flagellate spores are formed in the
central capsule : about 85 families and over 4,300 species,
which are found mostly in the deep sea.

FAMILY THALASSICOLLIDAE.

Skeleton wanting; central capsule simple, with a single nucleus.
THALASSICOLLA Huxley. Extra-capsular portion filled with alveoli
among which are numerous yellow algae.

T. pelagica Haeckel. Diameter 2 mm.: in the Mediterranean.

CLASS 2. MASTIGOPHORA. (FLAGELLATA.)

Protozoa whose motile organs consist of one or more long whip-like
projections called flagella. The body is provided with an external mem-
brane which, in many cases, is very delicate, the body being more or
less amoeboid. A membranous shell of silica, chitin, or cellulose is also
often present. In one group, the Choanoflagellida, the base of the single
flagellum is surrounded by a high ridge called the collar (Fig. 28). A
single nucleus is present, and usually a contractile vacuole.

The protoplasm usually shows no division into ectosarc and entosarc.
It often contains chromatophores which may be formed of chlorophyll
and green, or of diatomin and yellow or brown in color. Other bodies
allied to starch or oil are often present imbedded in the protoplasm.
Reproduction is by division and by spore formation; colony formation,
the result of incomplete division, is very common, the members of the
colony being sometimes enclosed in a common cellulose jelly, sometimes
connected by protoplasmic strands, and sometimes joined by both jelly

MASTIGOPHORA 25

and strands. The colony is in some cases very complex with division
of labor among the different individuals.

The Mastigophora have been known from the earliest period of
the study of microscopical animals under the general name of Flagellata,
and are still so known in many textbooks. The name Mastigophora
was given the group by Biitschli in 1883. The animals live in both
fresh and salt water, and many are parasites in the higher animals,
being often the cause of disease. Large numbers closely resemble
plants and many are on the border line between animals and plants. The
class contains 3 subclasses with about 350 species.

Key to the subclasses of Mastigophora:

Oj Small Mastigophora with a definite anterior and posterior end, at one or the
other of which are 1 or more flagella 1. FLAGELLIDIA

aa Mastigophora with usually 2 flagella, 1 anterior and 1 transverse in posi-
tion 2. DlNOFLAGELLIDIA

os Large marine Mastigophora with parenchymatous protoplasm.

3. CYSTOFLAGELLIDIA

SUBCLASS 1. FLAGELLIDIA.

Body with a well-defined cuticula which gives it a definite shape,
the cuticula in some forms, however, being so thin that changes in shape
often take place; pseudopodia formed in certain forms; many flagel-
lates are protected by external coverings of jelly, chitin, silica or
cellulose; 1, 2 or several flagella extend from one end of the body,
usually the forward; in the Choanoflagellida, however, the single flagel-
lum is at the hinder end and is surrounded at its base by a collar: 8
orders, in which are included the great majority of flagellates, very
many containing chromatophores and being apparently allied to plants.

Key to the orders of Flagellidia :

at Body colorless, often more or less amreboid, and with one or more flagella.
&! Body spiral with or without flagellum, and more or less like bacteria.

1. SPIBOCHETIDA
fca Body not spiral.

Cj One flagellum with collar present 3. CHOANOFLAGELLIDA

C2 No collar present.
di Body with indistinct cuticula, often more or less amreboid.

«! Body elongate with undulating membrane 5. TBYPANOSOMATIDA

e-t No undulative membrane present.
/! Two or more flagella, one directed forward, the other trailed behind.

4. HETEBOMASTIGIDA
/2 Flagella always directed forward.

fh One or two flagella ; body usually more or less amreboid . . 2. MONADIDA

02 Three or more flagella 6. POLYMASTIGIDA

dt Body with distinct cuticula 7. EUGLENIDA

Oj Body usually either yellow or green, often colonial.

Z>! Body with distinct cuticula, and usually solitary 7. EUGLENIDA

62 Body usually with a hyaline, gelatinous or cellulose house ; colonial.

8. PHYTOFLAGELLIDA

26 PROTOZOA

ORDER 1. SPIROCHETIDA.

Body elongate, spiral, with or without an undulating membrane;
flagellum very short or absent; nucleus diffuse: 1 family.

FAMILY SPIROCHETIDAE.

With the characters of the order: 3 genera.
1. SPIROCHETA Ehrenberg. Undulating membrane but
no flagellum present: about a dozen species;
mostly parasitic.

S. balbianii (Certes) (Fig. 20). Length .02
to .18 mm.; broad membrane present; ends
rounded: in the digestive tract of the oyster,
often in the crystalline style.

S. plicatilis Ehr. (Fig. 21).
Length .08 to .2 mm.; narrow
membrane present; ends rounded:
in stagnant water.

2. TREPONEMA Schaudinn. Fla-
gellum but no undulating mem-
Fig. 21 — Sptrocheta plica- £

tili* (Doflein). brane present: about 8 species.

T. pallidum Schaudinn (Fig. 22). Body cylindrical, without
membrane, .015 mm. long ; ends tapering, ending each in a fine flagellum :
in syphilitic lesions.

ORDER 2. MONADIDA.

Body usually without shell and more or less amoeboid, with 1 or 2
large flagella at the forward end and often 1 or more secondary flagella ;
no mouth : 5 families.

Key to the families of Monadida here described:

Ci Pseudopodia present 1. RHIZOMASTIGIDAE

02 Pseudopodia absent,
fcj One flagellum present.

G! Body not in a cup 2. CEBCOMONADIDAE

c, Body in a cup 3. CODONECIDAE

6a Two flagella present 4. HETEROMONADIDAE

FAMILY 1. RHIZOMASTIGIDAE.

Simple forms without mouth and with 1 or 2 flagella; occasionally
with either lobose pseudopodia like a rhizopod or stiff radial ones like
a heliozoan; food taken at any part of the body: 6 genera.

MASTIGAMCEBA F. E. Schulze. Body irregular in form with several
pseudopodia which disappear when the animal swims, and one long
flagellum: 6 species; in fresh and salt water.

MASTIGOPHOEA 27

M. verrucosa Kent (Fig. 23). Length about .015 mm.; many short
pseudopodia: in fresh water.

M. simplex Calkins. Ectosarc and entosarc distinct; flagellum
converted into a pseudopodium ; length .01 mm.: marine, on decaying
algae.

FAMILY 2. CEKCOMONADIDAE.

Body oval or elongate, frequently amoeboid, especially at hinder
end; with pseudopodia and with a long flagellum: 5 genera.

1. CERCOMONAS Dujardin. Form more or less spindle-shaped, pro-
longed posteriorly: 3 species; in fresh water.

C. longicauda Duj. Tail long; length up to .05 mm.

Fig. 23 Fig. 24 Fig. 25

Fig. 23 — Mastigamceba verrucosa (Calkins). Fig. 24 — Herpetomonas muscae
domesticae (Doflein). Fig. 25 — Codoneca gracilis (Calkins).

2. HERPETOMONAS Kent. Body elongate, very flexible; hinder end
often the more attenuate, but not forming a caudal filament: several
species; parasitic in insects.

H. muscae domesticae (Burnett) (Fig. 24). Length .05 mm.: in
intestine of the house-fly; common.

3. OIKOMONAS Kent. Form spherical or oval; frequently a pro-
jecting lip at base of flagellum; sometimes attached by a terminal fila-
ment : several species in fresh and salt water, often in infusions.

0. termo (Ehrenberg). Length .06 mm.: often very common in
fresh water.

FAMILY 3. CODONECIDAE.

Body enclosed in a gelatinous or hyaline cup: 2 genera.

CODONECA Clark. Ovoid or goblet-shaped, and attached to a caudal,
stalk; animal does not fill cup: 3 species; in fresh and salt water.

C. gracilis Calkins (Fig. 25). Cup urn-shaped with a distinct neck;
length .021 mm.: Woods Hole.

FAMILY 4. HETEKOMONADIDAE.

One or 2 accessory flagella present besides the main one; often
sessile or colonial, the animals being on a common stalk: 3 genera.

28 PEOTOZOA

Key to the genera of H eteromonadidae :

d Solitary forms 1- MONAS

o2 Colonial forms.

6X Common stalk branched once or twice ; on Cyclops . . 2. CEPHALOTHAMNIUM
62 Common stalk much branched 3. ANTHOPHYSA

1. MONAS Ehrenberg. Body spherical or ovate, occasionally fast-
ened by a thread-like stalk ; 2 flagella: 3 species; in fresh water.

Fig. 26 Fig. 27 Fig. 28

Fig. 26 — Monas elongata (Conn). Fig. 27 — Cephalothamnium ccespitosum (Conn).
Fig. 28 — Monosiga ovata (Calkins).

M. elongata (Stokes) (Fig. 26). Body elongate; hinder end tapers
to form stalk; length .01 mm.

2. CEPHALOTHAMNIUM Stein. Body ovate, with one long and one
short flagellum; animals colonial and sessile, the stalk branching two
or three times and several individuals being grouped at the end of each
branch : 2 species ; in fresh water, often on Cyclops.

C. csespitosum (Kent) (Fig. 27). Body with obliquely truncated
anterior end; length of individual .02 mm.

3. ANTHOPHYSA Bory. Body as in above; stalk much branched:
1 species; in fresh water.

A. vegetans (0. F. Miiller). Length of individual .03 mm., of
colony .4 mm.

ORDER 3. CHOANOFLAGELLIDA.

Collar flagellates. Collar-like ridge surrounding the base of the
single flagellum which is at the hinder end of the body when the animal
swims, instead of at the forward end as in other flagellates; in some
forms 2 collars are present, one over the other: 2 families.

FAMILY CRASPEDOMONADIDAE.

Either solitary or colonial and either free-swimming or sessile and
often enclosed in a cup or a gelatinous envelope: 4 genera.
Key to the genera of Craspedomonadidae :

Oi Shell wanting ; animals sessile or stalked.

&! Stalk shorter than body or wanting 1. MONOSIGA

Z>2 Stalk long, with many individuals at the end 2. CODONOSIGA

63 Stalk long, branched at end 3. CODONOCLADIUM

o. Shell present 4. SALPINGOSCA

MASTIGOPHORA 29

1. MONOSIGA Kent. Small colorless forms, solitary and sessile,
attached directly or by a short stalk : 9 species ; in fresh and salt water.

M. ovata Kent (Fig. 28). Individual ovate or spherical; length .08
mm.: in fresh and salt water.

2. CODONOSIGA Clark. Similar to Monosiga, but at the end of a
stalk and solitary or colonial: 1 species.

C. botrytis Clark. From 1 to 20 individuals in a colony; length of
individual .08 mm., of stalk .014 mm. : in fresh and salt water.

3. CODONOCLADIUM Stein. Like Codonosiga, but the stalk branches,
each branch bearing an individual: 4 species; in fresh and salt water.

C. umbellatum Stein. Number of branches 4 to 10, which some-
times also branch ; length .03 mm. : in fresh water.

4. SALPINGECA Clark. Solitary; body enclosed in a shell, usually
cup-shaped, which is directly attached at base or at the end of a short
stalk: about 27 species; in fresh and salt water.

5. steini Kent. Shell cylindrical; length .02 mm.: in fresh water.

ORDER 4. HETEROMASTIGIDA.

Two or more flagella present, one of which is directed forwards and
the others backwards, during locomotion; no shell present; animal
colorless: 2 families.

FAMILY BODONIDAE.

Small, naked forms with 2 flagella of nearly equal length : 4 genera.
Key to the genera of Bodonidae here described:

0! Flagella spring from anterior end.

Z>! Flagella longer than body, which is ovate 1. BODO

62 Flagella shorter than body, which is elongate 2. PHYLLOMITUS

o2 Flagella spring from a lateral groove 3. OXYBBHIS

Fig. 29 Fig. 30 Fig. 31

Fig. 29 — Bodo caudatus (Calkins). Fig. 30 — Phyllomitus amylophagus (Conn).
Fig. 31 — Oxyrrhis marina (Calkins).

1. BODO Ehrenberg. Body more or less ovate, often amoaboid;
anterior end pointed, with 2 flagella arising from a slight depression : 10
species; in salt and fresh water.

B. caudatus (Dujardin) (Fig. 29). Body ovate, often amoeboid;
flagella about the same length; length .018 mm.

30 PEOTOZOA

2. PHYLLOMITUS Stein. Body elongate and very flexible, with 2
flagella shorter than the body: 1 species.

P. amylophagus Klebs (Fig. 30). Length .018 mm.: in fresh water.

3. OXYRRHIS Dujardin. Body oval with pointed hinder end, at
side of which is a deep cavity from which the flagella emerge : 1 species ;
marine.

0. marina Duj. (Fig. 31). Length .04 mm.: at Woods Hole.

ORDER 5. TRYPANOSOMATIDA.

Body elongate, usually pointed, with an undulating lateral mem-
brane and 1 or 2 flagella which arise from a special nucleus (blepharo-
plast) and accompany the membrane as a lateral chord: 1 family.

FAMILY TRYPANOSOMIDAE.

With the characters of the order: several genera; parasitic in
invertebrate and vertebrate hosts and often the cause of deadly diseases.

Fig. 32 Fig. 33 Fig. 34

Fig. 32 — Trypanosoma gambiense (Doflein). Fig. 33 — Trypanosoma brucei (Doflein).
Fig. 34 — Hexamitus inflatus (Conn).

TRYPANOSOMA Gruby. But 1 flagellum present: over 60 species,
which are parasites of the blood system in all kinds of vertebrates and
are also found in the intestine of various blood-sucking insects, which
in many cases are known to convey the parasite to the vertebrate host
by their bite.

T. gambiense Button (Fig. 32). The cause of the deadly sleeping
sickness which affects man in western and central Africa ; it is conveyed
by Glossina palpalis, a tsetse fly ; length .03 mm.

T. brucei Plimmer and Bradford (Fig. 33). The cause of nagana, a
sickness fatal to horses and cattle and other animals in Africa and is
conveyed by Glossina morsitans, a tsetse fly.

T. evansi Steel. The cause of surra,* a fatal disease to horses and
cattle in Africa, Asia, and America and conveyed by horse flies.

ORDER 6. POLYMASTIGIDA.

Three or more flagella and usually several mouth openings present;
body colorless and without shell: 3 families.

* See "Collected Studies on the Insect Transmission of Trypanosoma evansi," by
M. B. Mitzraain, Bull. 94, Hyg. Lab., Wash., 1914,

MASTIGOPHOEA 31

FAMILY DISTOMIDAE.

Flagella in two symmetrical groups, with a mouth at the base of
each: 2 genera.

HEXAMITUS Dujardin. Body ovate, with 2 to 4 flagella at forward
end and hinder end prolonged into 2 thread-like processes: 3 species; in
fresh water, also parasitic in intestine of amphibians.

H. inflatus Duj. (Fig. 34). Posterior processes not close together;
length .027 mm.

ORDER 7. EUGLENIDA.

Large forms with usually a distinct, spirally striped cuticula;
1 or 2 flagella present at the forward end, with a so-called
pharynx at their base and a contractile vacuole opening into the
pharynx; frequently colonial and usually colored by chromatophores
in which 1 or more deeply staining bodies, the pyrenoids, may be
present; paramylum, a substance allied to starch, also usually present:
3 families.

Key to the families of Euglenida:

&! Chlorophyll usually present 1. EUGLENIDAE

C2 Chlorophyll absent.

Z>! Without distinct mouth ; saprophytic 2. ASTASIIDAE

63 With distinct mouth ; holozoic 3. PAEANEMIDAE

FAMILY 1. EUGLENIDAE.

Body spindle or pear-shaped with usually a single flagellum; chloro-
phyll, pyrenoids, and paramylum and an eye-spot almost invariably
present; contractile vacuole or vacuoles open into a reservoir which
opens into the pharynx; nutrition mostly holophytic, in some cases
saprophytic : 6 genera.

Key to the genera of Euglenidae:

Q! With one flagellum.

&! Cuticula elastic, animals more or less plastic.
Ci Animal not in a shell.

h Animal free-swimming 1. EUGLENA

d2 Usually attached to other animals 2. COLACIUM

c2 Animal in a shell 3. TRACHELOMON AS

62 Cuticula not elastic and animal not plastic.

cx Chromatophores disc-shaped 4. PHACUS

c2 Chromatophores in two longitudinal bands * 5. CBYPTOGLENA

a2 With two flagella 6. EUTREPTIA

1. EUGLENA Ehrenberg. Large spindle-shaped flagellates with
spirally marked cuticula; 1 flagellum, at the base of which are the
pharynx, eye-spot, and contractile vacuole; color usually green or
red, a few being colorless: species numerous; in fresh and brackish
water.

32

PROTOZOA

Fig. 35

Euglena

viridis

(Doflein).

E. viridis Ehr. (Fig. 35). Length .1 mm. or less; body lenticular:
often very common in pools, which it may color green.

E. acus Ehr. Body very long, even filiform, pointed behind; length
.18 mm.

E. deses Ehr. Body elongate, .2 mm. long, with nearly
parallel sides: common.

2. COLACITTM Ehrenberg. Like Euglena, but usually
attached by a short stalk at the forward end to small ani-
mals; flagellum present in free-swimming condition, but
usually not present when attached : 3 species ; in fresh water.

C. steini Kent. On Diaptomus; length .04 mm.

3. TRACHELOMONAS* Ehrenberg. Like Euglena, except
the animal has a brown or colorless shell: numerous species;
in fresh and salt water.

T. lagenella Stein. Shell ovoid or cylindrical and
smooth; length .03 mm.

T. hispida (Perty). Shell ovoid, covered with spines
and usually dark brown in color; length .03 mm.

T. armata Ehr. (Fig. 36). Shell brown, punctate; 2
rows of spines around aperture and spines often around
posterior end; length .04.

4. PHACTJS Nitzsch. Body somewhat asymmetrical, flattened or
pear-shaped, with spiral strips; hinder end spine-like; chromatophores
disc-shaped: 6 species; in fresh water.

P. pyrum (Ehrenberg) (Fig. 37).
Body top-shaped; length .03 mm.

P. longicaudus Dujardin. Hinder
spine very long; length .08 mm.

5. CRYPTOGLENA Ehrenberg. Body
oval, rigid, with 2 lateral green chromato-
phores and an eye-spot : 1 species.

0. pigra Ehr. Length .015 mm.: in
fresh water.

6. ETTTREPTIA Perty. Like Euglena, but with 2 flagella; body very
flexible; chromatophores disc-shaped: 1 species.

E. viridis Perty. Length .05 mm. : in fresh water.
FAMILY 2. ASTASIIDAE.

Elongated, colorless, more or less amreboid flagellates without eye-
spot and usually with striped membrane; sometimes with an accessory
flagellum: 6 genera.

* See "Delaware Valley Forms of Trachelomonas," by T. C. Palmer, Proc. Acad.
Nat. Sci., 1905.

Fig. 36

Fig. 37

Fig. 36 — Trachelomonas armata

(Palmer). Fig. 37 — Phacus

pyrum (Conn).

MASTIGOPHORA

33

Key to the genera of Astasiidae here described:

«! Body very flexible 1. ASTASIA

a, Body rigid, sickle-shaped 2. MENOIDIUM

1. ASTASIA Ehrenberg. Body spindle-shaped; very
plastic, with striped cuticula: 2 species; in fresh and salt
water.

A. contorta Dujardin (Fig. 38). Length .06 mm.:
in decaying vegetation.

2. MENOIDIUM Perty. Body elongate and more or
less bent, and rigid; cuticular stripes longitudinal: 1
species.

M. pellucidum Perty. Length .08 mm.: in fresh
water.

FAMILY 3. PERANEMIDAE.

Fig. 38

Astasia
contorta
(Calkins).

Body usually cylindrical or ovate, plastic or rigid,
and covered by a striped cuticula; 1 or 2 flagella present, at the
base of which is a distinct mouth; no chlorophyll present: 14
genera.

Key to the genera of Peranemidae here described :

ox Body plastic.
6X Body elongate, attenuated forward ........................ 1. PEBANEMA

&, Body bottle-shaped ...................................... 2. UBCEOLUS

o2 Body rigid ; two flagella.
&! Pharynx not deep ...................................... 3. ANISONEMA

6a Pharynx very deep .................................... 4. ENTOSIPHON

1. PEEANEMA Dujardin. Body tapers from behind
forward and very plastic, with a spirally striated cuticula
and a single flagellum, the tip of which vibrates when the
animal moves: 1 species.

P. trichophonim (Ehrenberg) (Fig. 39). Length .08
mm.: in fresh water.

2. URCEOLTJS Mereschkowski. Body spherical or ovate
with a neck from which the flagellum emerges :

1 species.

U. cyclostomus (Stein). Length .03 mm.:
in fresh water.

3. ANISONEMA Dujardin. Body ovate and
compressed with striated cuticula and a
laieT&l g^,^. 2 flagella, 1 of which trails
behind: 3 species; in fresh and salt water.

A. vitreum Duj. Body transparent and with longitudinal furrows;
length .05 mm.

Fig. 39
Peranema

Fig. 40

Entosiphon
sulcatum
(Conn).

34 PROTOZOA

4. ENTOSIPHON Stein. Body ovate, with 2 flagella of nearly equal
length, one of which trails behind, a deep ventral furrow and a very
deep pharynx: 2 species.

E. sulcatum St. (Fig. 40). Length .02 mm.: in fresh and salt water.

ORDER 8. PHYTOFLAGELLIDA.

Flagellates which include most of those forms with holophytic or
saprophytic nutrition, and are often classed as plants; most of them
are enclosed in a cellulose shell or jelly; yellow, green or brown chro-
matophores usually present ; very many are colonial : 4 suborders.

Key to the suborders of Phytoflagellida here described :

«i Yellow chromatophores usually present 1. CHEOMOMONADINA

02 Green chromatophores usually present.

6j Mostly non-colonial ; 2 or 4 flagella 2. CHLAMYDOMONADINA

63 Colonial ; 2 flagella 3. VOLVOCINA

SUBORDER 1. CHROMOMONADINA.

Flagellates with a delicate cuticula and often somewhat amoeboid,
which are usually enclosed in a shell or jelly, and are often colonial;
yellowish or bluish chromatophores and 1 or 2 flagella present: 2
families.

Key to the families of Chromomonadina :

»! Color yellowish ; no pharynx present 1. CHEYSOMONADIDAE

o2 Color blue, green or brown, or colorless ; deep pharynx present.

2. CBYPTOMONADIDAE

FAMILY 1. CHEYSOMONADIDAE.

Body usually with a shell or in a jelly, with 1 or 2 flagella and always
with 1 or 2 yellowish chromatophores, and with or without eye-spots;
nutrition usually holophytic: 15 genera.

Key to the genera of Chrysomonadidae here described :

al Body in a shell which it does not fill 1. DINOBBYON

o2 Body in a shell which fits it closely.

&! One flagellum 2. MALLOMONAS

63 Two flagella.

ct Flagella of equal length 3. SYNUBA

c2 One flagellum long, one short ; colonial 4. UBOGLENA

1. DINOBRYON Ehrenberg. Free-swimming branched colonies, each
individual of which is in a transparent cup-shaped shell which springs
from just inside the opening of the shell next behind it; 2 flagella of
unequal length, 1 or 2 yellowish or brownish chromatophores, and an
eye-spot present: 3 species; in fresh water.

MASTIGOPHORA

35

D. sertularia Ehr. (Fig. 41). Shell .04 mm. long: in fresh water,
often in great quantities; sometimes fouls the water in reservoirs and
ponds.

2. MALLOMONAS* Perty. Free-swimming and solitary, with closely
fitting reticulated oval shell bearing long spines; 2 yellowish chromato-
phores; without eye-spot; 1 flagellum: several species in fresh water,
which may produce an odor and injure water supplies.

M. punctifera (Ehrenberg). Spines all over shell; length .035 mm.

3. SYNTJRA Ehrenberg. Swimming spherical colonies of about 50
radially arranged individuals; each individual with 2 flagella, 2 brown
chromatophores, eye-spots and sometimes spinose: 1 species.

S. uvella Ehr. (Fig. 42). Length of individual .03 mm.: in fresh
water.

4. UROGLENA Ehrenberg. Swimming spherical colonies composed
of many individuals in a jelly; individual pear-shaped, with 2 unequal

Fig. 41

Fig. 42

Fig. 43

Fig. 41 — Dinobryon sertularia (Conn). Fig. 42 — Synura uvella (Conn).
Fig. 43 — Uroglena americana (Calkins).

flagella, 2 yellow chromatophores, and an eye-spot: 2 species; in fresh
water.

U. americana Calkins (Fig. 43). Length of individual .006 mm.:
the cause of the fishy taste of the water in some reservoirs.

FAMILY 2. CRYPTOMONADIDAE.

Body with a firm cuticula and not amoeboid ; 2 equally long flagella,
at the base of which is a long pharynx extending to the middle of the
body; 2 chromatophores present or absent: 3 genera.

Key to the genera of Cryptomonadidae:

Oj Without chromatophores.

&! A row of highly refractive bodies in forward part of body. . .1. CYATHOMONAS
62 Without such bodies 2. CHILOMONAS

o2 With chromatophores 3. CBYPTOMONAS

* See "Note on the Vertical Distribution of Mallomonas," by G. C. Whipple and
H. N. Parker, Am. Nat, Vol. 33, p. 485, 1899.

36 PROTOZOA

1. CYATHOMONAS Fromentel. Body colorless, ovoid, flattened, with
obliquely truncated forward end, with 2 flagella of nearly equal length;
parallel with the anterior border is a row of highly retractile bodies:
1 species.

C. truncata (Fresenius) (Fig. 44). Length .023 mm.: in fresh
water and infusions.

2. CHILOMONAS Ehrenberg. Body colorless, oval, compressed; for-
ward end obliquely notched, with two equally long flagella: 2 species;
in fresh water and infusions.

Fig. 44 Fig. 45 Fig. 46

Fig. 44 — Cyathomonas truncata (Conn). Fig. 45 — Chilomonas paramecium (Conn).
Fig. 46 — Chlamydomonas pulvisculus (Conn).

C. paramecium Ehr. (Fig. 45). Body ellipsoid; length .03 mm.:
very common.

3. CRYPTOMONAS Ehrenberg. Like Chilomonas, but with 2 green or
brown chromatophores : 2 species; in fresh and salt water.

C. ovata Ehr. Length .03 mm.: in fresh water, to which it may
give a fishy taste.

SUBORDER 2. CHLAMYDOMONADINA.

Body green in color with 2 or 4 flagella and usually a firm cuticula
or shell within which division takes place: 2 families.

FAMILY CHLAMYDOMONADIDAE.

Cuticula very delicate with no large pores: 7 genera.

1. CHLAMYDOMONAS* Ehrenberg. Body spherical to cylindrical
with 2 flagella and an eye-spot, a delicate shell, prominent chromato-
phores and 2 contractile vacuoles: about 6 species; in fresh water.

C. pulvisculus Ehr. (Fig. 46). Body spherical, about .02 mm. in
diameter: in fresh water, to which it gives an oily flavor.

2. SPONDYLOMORTJM Ehrenberg. Colony of 16 cells in 4 alternating
rows, each cell with 4 flagella: 1 species.

S. quaternarium Ehr. Diameter of colony .05 mm. : in fresh water.

3. POLYTOMA Ehrenberg. Body ellipsoid with a delicate shell and
2 flagella, colorless, occasionally with an eye-spot ; 2 contractile vacuoles ;

* See "Chlamydomonas and Its Effect on Water Supplies," by G. C. Whipple,
Trans. Am. Micro. Soc., Vol. 21, p. 97, 1900.

MASTIGOPHORA

37

reproduction by division into 4 or 8 cells, which remain in the shell and
then become free: 2 species.

P. uvellum Ehr. (Fig. 47). Length .02 mm. : in .

fresh water.

f

SUBORDER 3. YOLVOCINA.

Colonial flagellates, the individual cells of uvellum

which have each 2 flagella, an eye-spot and green

chromatophores, and are imbedded in a common cellulose jelly; repro-
duction sexual and asexual: 7 genera, all represented in America; in
fresh water.

Key to the genera of Volvocina:

<*! Colony in form of a plate.
&! Flagella on one side only of colony.

G! Colony squarish 1. GONIUM

c2 Colony round with a spheroid envelope 2. STEPHANOSPH^EA

62 Flagella on both sides 5. PLATYDORINA

a2 Colony spherical or ellipsoidal.
&! Colony microscopic.

G! Cells crowded, reaching center of colony 3. PANDOBINA

c2 Cells not thus crowded.

dt Cells alike in size 4. EUDOEINA

dz Anterior cells small, posterior ones large 6. PLEODORINA

&2 Colony not microscopic and composed of a large number of cells ... 7. VOLVOX

1. GONIUM 0. F. Miiller. Colony of few and similar individuals

forming a squarish plate with the flagella on one
face only; asexual reproduction by repeated divi-
sion of all the cells, each forming a new colony;
sexual reproduction the result of the conjugation
of pairs of similar individuals, the zygotes thus
formed, after a resting stage, each developing into
a colony : 2 species, 1 American ; in fresh water.

G. pectorale 0. F. Mill. (Fig. 48). Colony
consists of 16 cells and .06 mm. in diameter:
cosmopolitan.

2. STEPHANOSPHJERA Cohn. Colony consisting of 4 or 8 cells ar-
ranged in a ring which is surrounded by a large rounded envelope of
which the cells form the equator; reproduction as in Gonium: 1 species.

S. pluvialis Cohn. Envelopes up to .06 mm. in diameter.

3. PANDORINA Boxy de Vincent. Colony more or less spherical,
composed of 16 or 32 crowded cells which reach the center and are sur-
rounded by a lamellate envelope; reproduction as in Gonium , except that
the conjugating cells may differ slightly in size : 1 species.

Fig. 48

Gonium pectorale
(Doflein).

38

PROTOZOA

P. morum Bory. (Fig. 49). Colony up to .09 mm. in diameter:
cosmopolitan.

4. EUDORINA Ehrenberg. Colony more or less spherical, composed

usually of 32 (occasionally of 16 or 64 cells) which are
not close together and do not reach the center, and
are surrounded by an envelope; asexual reproduction
as in Gonium; at certain times sexual colonies appear,
the female being like the ordinary colony, the male
colony consisting of long, spindle-like cells which be-
come free and unite with the female cells forming the
zygotes: 2 species.

E. elegans Ehr. (Fig. 50). Colony about .15 mm.
in diameter: cosmopolitan.

5. PLATYDORINA* Kofoid. Colony flattened, horseshoe-shaped, com-
posed of 16 or 32 cells with the flagella on both faces on alternate cells
which are alike; asexual reproduction as in Gonium; sexual reproduction
not observed: 1 species.

P. caudata Kofoid (Fig. 51). Colony about .15 mm. long and .13
mm. wide ; posterior end of envelope with 3 or 5 tails : Illinois.

Fig. 49

Pandorina morum
(Conn).

Fig. 50 Fig. 51 Fig. 52

Fig 50 — Eudorina elegans (Jordan and Kellogg). Fig. 51 — Platydorina caudata

(Kofoid). Fig. 52 — Pleodorina illinoisensis (Kofoid).

6. PLEODORINA Shaw. Colony more or less spherical, composed of
16 to 128 cells, certain of which are reproductive and the rest vegeta-
tive, the former being twice the size of the latter, and posterior in
position; asexual reproduction as in Gonium; sexual reproduction not
observed: 2 species; both in America.

P. calif ornica Shaw. Cells 64 or 128, half of which are vegetative :
California.

P. illinoisensisf Kofoid (Fig. 52). Cells 32, rarely 16 or 64, 4 of
which are vegetative, .12 mm. in diameter: Illinois.

* See "On Platydorina," etc., by C. A. Kofoid, Bull. 111. St. Lab., Vol. 5,
p. 419, 1899.

t See "On Pleodorina Illinoisensis," etc., by C. A. Kofoid, 111. St. Lab.,

Vol. 5, p. 273, 1898.

MASTIGOPHOEA 39

7. VOLVOX* L. Colony forms a hollow sphere of large size and
composed of hundreds or thousands of cells connected by protoplasmic
threads, and not differing in size; asexual reproduction by so-called
parthenogonidia which are cells in the center of the colony (1 to 9 in
number), which form there by repeated division daughter-colonies; at
certain times sexual cells appear, the androgonidia and gynogonidia,
which retire to the center of the colony where
the latter are fertilized by the former and
after a resting period the zygotes develop into
new colonies: several species; in all parts of
the world.

V. globator L. (Fig. 53). Colony of 1,500 to

22.000 cells and up to 1.2 mm. in diameter; pro-
Fig. 53— Volvox
toplasmic threads may contain chromatophores : globator

cosmopolitan.

V. aureus Ehrenberg (V. minor Stein). Colony of 200 to 4,000
cells and up to .85 mm. in diameter; protoplasmic threads contain no
chromatophores : cosmopolitan.

SUBCLASS 2. DINOFLAGELLIDIA.t

Flagellates in most cases with a shell, around the equator of which
is a transverse groove in which lies a flagellum; a second flagellum is
also in most cases present, which may spring from a second and vertical
groove; body sometimes colored by chromatophores: 3 orders.

Key to the orders of Dinoftagellidia here described :

at No transverse groove ; 2 flagella at forward end 1. ADINIDA

oa Two grooves, a transverse and a longitudinal 2. DINIFERIDA

ORDER 1. ADINIDA.

Body without groove; 2 flagella at the forward end; shell composed
of a right and a left half: 2 genera.

1. EXUVIELLA Cienkowsky. Body ovoid, shells compressed and
composed of right and left valves; 2 brown chromatophores present: 5
species; marine.

* See "New Forms of Volvox," by J. H. Powers, Trans. Am. Mic. Soc., Vol. 27,
p. 123. "Light Reactions in Lower Organisms — II Volvox," by S. O. Mast, Jour.
Comp. Neur. and Psy., Vol. 17, p. 99, 1907. "Le Volvox," by C. Janet, 1912.

t See "New Species of Dinoflagellates," by C. A. Kofoid, Bull. Mus. Com. Zool.,
Vol. 50, p. 163, 1907. "Dinoflagellata of the San Diego Region," by same, Univ. of
Cal. Pub. Zool., Vol. 3, p. 299, 1907.

40

PROTOZOA

E. lima (Ehrenberg) (Fig. 54). Anterior border of both shells
slightly indented; length .04 mm.; slow of movement: at Woods Hole.

ORDER 2. DINIFERIDA.

Two grooves present, a transverse and a longitudinal: 2 families.
Key to the families of Diniferida:

«! Transverse groove near middle of body 1. PEBIDINIDAE

o2 Transverse groove above the middle 2. DINOPHYSIDAE

FAMILY 1. PERIDINIDAE.

Transverse groove medium; longitudinal groove short; shell, when
present, composed of plates or not; plates either equatorial (bordering
the transverse furrow), apical, or antiapical, while a rhombic plate may
extend from the transverse furrow to the apex: about 4 genera.

Key to the genera of Peridinidae:

a: With shell.

6X Reticular markings on shell.
cx Anterior part of shell with 7 equatorial and 1 rhombic plates.

1. PERIDINIUM
C2 Anterior part of shell with 3 equatorial and no rhombic plates.

2. CEBATIUM

62 No markings on shell 3. GLENODINIUM

c2 Without shell 4. GYMNODINIUM

1. PERIDINIUM* Ehrenberg. Body globular or elongate; shell with
distinct transverse groove, which may be spiral and with about 20
plates: 9 species, fresh and salt water; many species are reddish in
color and may be in sufficient numbers to color the sea.
P. digitale Pouchet (Fig. 55). Shell with large
pits and with oblique furrow, 1 posterior and 2
anterior spines; length .06 mm.: Woods
Hole; marine; common.

P. divergens Ehr. Shell spherical,
tapering posteriorly, with 2 large spines
anteriorly ; length .07 mm. : Woods Hole ;
marine; common.

2. CERATiUMf Schrank. Body a
flattened sphere with 3 long projections;

Fig. r>4 — Exuviella transverse groove either spiral or cir-
lima (Calkins). , , -La* i „

cular; longitudinal groove usually wide;

shell reticulate or striped and composed of 10 plates ; color usually green
or brown: numerous species; in fresh and salt water.

* See "Peridinium and the 'Red Water' in Narragansett Bay," by A. D. Mead,
Sci. N. S., Vol. 8, p. 707, 1898.

t See "Mutations in Ceratium," by C. A. Kofoid, Bull. Mus. Comp. Zool., Vol. 52,
p. 213, 1909.

Fig. 55

Peridinium

digitale
(Calkins).

MASTIGOPHOEA

41

C. tripos Ehrenberg (Fig. 56). Body triangular with 1 very long
and 2 short curved projections; length .29 mm.: Woods Hole; marine;
common.

C. fusus Ehr. Animal very elongate, due to presence of 2 long
projections in the same line; length .28 mm.: Woods Hole; marine;
common.

3. GLENODINIUM Stein. Small globular forms with a transverse

Fig. 56

Fig. 57

Fig. 58

Fig. 56 — Ceratium tripos (Calkins). Fig. 57 — Glenodinium compressum (Calkins).
Fig. 58 — Gymnodinium gracile (Calkins).

groove on anterior half and a short longitudinal one; shell soft and
structureless and without markings: 6 species; in fresh and salt water.

G. compressum Calkins (Fig. 57). Body ovoid, compressed, with
deep transverse and longitudinal grooves; hinder end often pointed and
this point becomes attached; length .04 mm.: Woods Hole.

4. GYMNODINIUM Ehrenberg. Body without shell and spherical,
sometimes pointed or flattened: 8 species; in fresh and salt water.

G. gracile Bergh (Fig. 58). Transverse groove in anterior half;
longitudinal groove long; color brown; length .06 mm.: Woods Hole;
marine.

FAMILY 2. DINOPHYSIDAE.

Transverse groove near upper end of body, its edges as well as edge
of the longitudinal groove being usually produced .into
characteristic ledges.

1. AMPHIDINITJM Claparede and Lachmann. Body
ovoid and flattened; longitudinal groove extending from
hinder end to transverse groove near forward end; shell
absent; color, brown or green: 2 species; in fresh and
salt water.

A. operculatum Cl. and Lach. (Fig. 59). Length .04
mm.: Woods Hole.

SUBCLASS 3. CYSTOFLAGELLIDIA.

Marine flagellates of large size with a parenchymatous protoplasm:
several genera.

Fig. 59

Amphidinium

operculatum

(Calkins).

42 PEOTOZOA

NOCTILTTCA Suriray. Body spherical and 1 mm. or less in diameter,
with a median groove in which lies a large feeler and a small flagellum,
as well as the mouth; single nucleus present; reproduction by division
and by spore-formation: 1 species; marine.

N. miliaris Sur. In the Atlantic and Pacific Oceans; often so plen-
tiful that the sea is colored red by day and glows by night with an
intense phosphorescent light.

CLASS 3. SPOROZOA.*

Parasitic protozoans which live in the cells, tissues, and open spaces
of other animals. The body is usually bounded by a thick cutieula; it
has no external openings or contractile or gastric vacuoles, and in most
cases but one nucleus. In the adult condition there are no organs of
locomotion, although the animals have often the power of sluggish
movement. Being entoparasites, all Sporozoa absorb food in a fluid
or gaseous form through the outer surface of the body.-* Reproduction
is carried on through the medium of spore formation, which usually
follows encystment, the reproductive processes being in many forms
very complex. Simple division does not occur. The Sporozoa are very
widely distributed, living as parasites in every class of animals from
Protozoa to Vertebrata: they are often the cause of disease both in
man and the lower animals. The class contains two subclasses and
about 400 known species, besides about as many uncertain species.

Key to the subclasses of Sporozoa:

Oi Sporozoa in which spore formation ends the individual life, including the great
majority of the class 1. TELOSPORIDIA

aa Sporozoa in which the entire cell does not form spores but sporocysts are
formed during life 2. NEOSPORIDIA

SUBCLASS 1. TELOSPORIDIA.

In these Sporozoa the individual life ends with spore formation,
the entire cell forming spores: 3 orders.
Key to the orders of Telosporidia:

al Parasitic as adults in the open spaces and organs of the host. .1. GREGARINIDA

cz Parasitic in the solid tissues and not the open spaces 2. COCCIDIIDA

o3 Parasitic in the blood of vertebrates 3. H^MOSPORIDIIDA

ORDER 1. GREGARINIDA.

Usually elongate Sporozoa with a thick cutieula and a distinct
nucleus; life history includes two stages, an attached stage, when the
animals are known as cephalonts, and a detached and sporulating stage,

* See "Sporozoa," by A. Labbe", Das Tierreich, 1899.

SPOEOZOA

43

when they are called sporonts and live in the open spaces of the organ
to the walls of which they have been attached; body in most cases
made up of two or three parts (Fig. 65), the epimerite at the forward
end, which is the organ of attachment of the cephalont and may be
dropped by the sporont, and the body, which may be divided by a septum
into the deutomerite which forms the bulk of the body and contains the
nucleus and the protomerite which lies between it and the epimerite:
about 300 species grouped in 2 suborders.
Key to the suborders of Gregarinida:

at Gregarines with an epimerite, and with or without a septum between the

deutomerite and protomerite 1. CEPHALINA

a2 Gregarines without epimerite and consisting of a single chamber.

2. ACEPHALINA

SUBORDER 1. CEPHALINA.

Fig. 60—Gregarina Watta-
rum (Doflein). A, two indi-
viduals, each with protomer-
ite and deutomerite ; B, cyst ;
C, spore.

Gregarines possessing an epimerite at
some stage of their life which is sunk
into the walls of the organs of the
host in which they live; body usually elon-
gate, the animals being often in associated
couples or groups arranged tandem, in
which case the first individual is called the
primite and the others the satellites: in
arthropods as adults, especially in the intes-
tine of myriapods, beetles and Orthoptera;
10 families and about 100 species.

Key to the families of Cephalina here
described :

ax Spore more or less ovoid 1. GREGABINIDAE

a2 Spore not ovoid.

&! Epimerite asymmetrical 2. DACTYLOPHOKIDAE

&2 Epimerite symmetrical.

cx Spore symmetrical, animal solitary 3. ACTINOCEPHALIDAE

c2 Spore asymmetrical.

dj Spore crescent-shaped ; animal solitary 4. MENOSPORIDAE

d2 Spore ovoid with polar thickening ; in marine annelids . . 5. DOLIOCYSTIDAE

FAMILY 1. GREGABINIDAE.*

Individuals either associated, forming a chain with a septum sep-
arating each two individuals, or solitary; epimerite simple and sym-
metrical: 8 genera and about 35 species.

* See "List of the Polycystid Gregarines of the United States," by H. Crawley,
Proc. Acad. Nat. Sci., Vol. 55, p. 41, 1903. "The Polycystid Gregarines of the United
States," by H. Crawley, same, p. 632. "Movements of the Gregarines," same, Vol. 57,
p. 89. "Study of Some Gregarines," etc., by M. C. Hall, Stud, from Zool. Lab. Univ.
Neb., No. 77, 1907. "The Polycystid Gregarines of the United States," by H. Crawley,
Proc. Acad. Nat. Sci., 1907, p. 220.

44

PEOTOZOA

Fig. 61

Gregarina

achetae-

abbreviatae

(Crawley).

Key to the genera of Gregarinidae here described :

Oj Individuals usually associated 1. GREGABINA

o2 Individuals usually solitary 2. STENOPHOBA

1. GREGARINA Dufour. Individuals usually associated; epimerite
simple and small but varying in form, being conical or spherical; cysts

spherical or ovoid, when ripe with long projections called
sporoducts through which the spores emerge: about 20
species; in the digestive tract of insects.

G. blattarum von Siebold (Fig. 60). Body elongate
but somewhat irregular; cyst ovoid with long sporo-
ducts; length about .5 mm.: in the intestine of the
cockroach.

G. achetae-abbreviatae Leidy (Fig. 61). Deutomerite
ellipsoidal or oval; protomerite hemispherical; animals
solitary or in pairs; length .5 mm.: in the common
cricket.

G. melanopli Crawley. Protomerite cubical or flat-
tened; deutomerite more or less rectangular; length .37
mm.: in intestine of the grasshopper.

G. locustae-carolinae Leidy. Protomerite globular on
which the epimerite appears as a small round knob ;
deutomerite globular; length .35 mm.: in intestine of the
large grasshopper, Dissosteira Carolina.

2. STENOPHORA Labbe. Body large, ovoid or elongate ;
cyst without sporoducts ; protomerite small : 4 species.

S. juli Frantzius (Fig. 62). With the characters of the genus;
protomerite often conical: very common in the intestine of Julus.

Fig. 62

Stenophora

juli
(Crawley).

FAMILY 2. DACTYLOPHOBIDAE.

Epimerite asymmetrical and irregular, with digitiform processes:
5 genera.

1. ECHINOMERA Labbe (EchinocepTialus Schnei-
der). Body ovoid and massive; epimerite conical
with the apex excentric and varied in form:
1 species.

E. hispida (Schneider) (Fig. 63). Deutomerite
eight or ten times as long as the other two divi-
sions; animal very active: common in gut of
Lithobius.

2. TRICHORHYNCHUS Schneider. Protomerite cylindrical or trun-
cated with a long rostrum : 1 species.

Fig. 63 Fig. 64

Fig. 63 — EcU-
nomera hispida (from
Bronn). Fig. 04 —
Amphoroides fonta-
riae (Crawley).

SPOROZOA 45

T. pulcher Schneider. In the intestine of Scutigera; length .07 mm.

FAMILY 3. ACTINOCEPHALIDAE.

Solitary animals with symmetrical epimerite; spores symmetrical
and spindle-shaped: 17 genera and about 27 species.

1. AMPHOROIDES Labbe. Epimerite simple and regular, with a
conical point; protomerite very short and cup-like; spores biconical:
2 species.

A. fontariae Crawley (Fig. 64). Deutomerite a long oval, hinder
end being always blunt; protomerite circular or pen-
tagonal; length .13 mm.: in diplopods of the family
Polydesmidae; often numerous.

2. ASTEROPHORA Leger. Epimerite mucronate and
elongate; protomerite usually larger than the deutom-
erite: 3 species.

A. cratoparis Crawley (Fig. 65). Deutomerite lance-
olate, terminating bluntly ; protomerite round with a j^g. 65
conical projection in front; epimerite small, consisting of Asterophora
a number of ribs; length .5 mm.: in curculionid beetles. (Crawley).

FAMILY 4. MENOSPOEIDAE.

Epimerite large, joined by a long neck with the
protomerite; spores crescent-shaped: 2 genera.

HOPLORHYNCHUS Carus. Animals solitary; elliptical
in shape; epimerite with 6 to 8 long marginal teeth:
2 species.

H. actinotus (Leidy) (Fig. 66). Deutomerite conical
with a pointed hinder end; protomerite small, tending to
' n fuse with the deutomerite; epimerite long, with a large
actiiwtus spreading front end; length .5 mm.: in Scolopocryptops,
(Crawley). a diplopod.

FAMILY 5. DOLIOCYSTIDAE.

Deutomerite not separate from protomerite : spore ovoid, with polar
thickening: 1 genus.

DOLIOCYSTIS Leger. With the characters of family: 6 species.

D. rhyncoboli Crawley. Deutomerite long, tapering to the hinder
end; protomerite and epimerite small: in the intestine of Rhynchobolus
americanus.

PROTOZOA

Pig. 67 — Monocystis lumbrici (from Bronn),

A, single individual ; B, a spore ;

C, a cyst.

SUBORDER 2. ACEPHALINA.

No epimerite present, the body consisting of a single chamber;
spore spindle-shaped : about 10 genera and numerous species, which live

principally in the body cavity
of the host and the organs con-
nected with it.

MONOCYSTIS Stein. Body
ovoid or elongate, sometimes
with long cuticular filaments;
individuals mostly solitary :
about 10 species.

M. lumbrici (Henle)
(M. agilis Stein) (Fig. 67).
Length .2 mm.: in intestine, genital organs and coelom of the earth-
worm; common.

M. clymenellae* Porter. In the body wall of Clymenella torquata.

ORDER 2. COCCIDIIDA.

Sporoeoa of spherical or ovoid shape without a free stage, which
live imbedded in the solid tissues of the host, usually as intracellular
parasites; reproduction by sporulation with an
alternation or generations: 5 families and 70
species.

ElMERIA Schneider (Coccidium Leuckart).
Cyst ovoid, each on sporulation forming 4 sporo-
blasts, each of which produces 2 spores: 13
species.

E. stiedae (Lindemann) (E. cuniculi Rivolta)
(Fig. 68). In the liver and other organs of

rabbits and other animals, also in the human liver; length of cyst
.04 mm.

ORDER 3. H^GMOSPOEIDIIDA.

Sporozoa parasitic in the blood of vertebrates, with or without a
change of hosts ; reproduction occurs by asexual spore-formation usually
in the body of some other animal where conjugation takes place fol-
lowed by pseudosexual spore-formation: about 4 genera.

1. PLASMODITTM Marchiafava and Celli. An intra-corpuscular para-
site in mammalian blood corpuscles where it finally breaks up into about
12 asexual spores (merozoites) which are often grouped about a central

• See "Two New Gregarinida," by J. F. Porter, Jour. Morph., Vol. 14, 1908.

Fig. 68 — Eimeria
stiedae (Doflein). An
infected intestinal epi-
thelium.

SPOEOZOA

47

Fig. 69 — Plasmodi-
um malariae (Doflein).
The 6 circles represent
blood corpuscles into
which the parasite has
entered (A), where it
l it fills the

grows unti
orpuscle (E)

and

body composed of melanin pigment, and then enter other corpuscles;

spore-formation occurs every seventy-two hours or oftener, and is

accompanied by a chill in the patient followed by a fever; if the blood

is drawn into the intestine of a mosquito of the genus Anopheles certain

of these spores produce flagellate individuals (micro g ametes) , and others

produce rounded spores (macro gametes) ; these two

conjugate, and motile individuals (zygotes) are the

result, which penetrate the intestinal mucous mem-
brane and form large cysts on its outer surface;

here they sporulate and develop finally into long,

slender sporozoites which migrate into the body

cavity and then into the salivary glands of the

mosquito and are injected with the saliva into the

blood of the next person the mosquito bites:

3 species.

P. malariae (Laveran) (Fig. 69). The cause

of quartan malaria, in which the chill and fever

occur every seventy-two hours.

P. vivax Grassi and Feletti. The cause of the tertian malaria in

which the chill and fever occur every forty-eight hours.

P. f alciparum Welch. The cause of pernicious or autumnal malaria

in which the chill and fever occur every tAventy-four hours, or irregularly.

2. BABESIA Starcovici (Pyrosoma Smith
and Kilbourne; Piroplasma Patton). An intra-
corpuscular parasite of mammalian blood-
corpuscles, without melanin pigment; trans-
mission by the bite of ticks in whose intestine
the pseudosexual processes occur: many
species.

B. hominis (Hanson) . The cause of Rocky

Mountain spotted fever in man, the tick involved being Dermacentor

venustus.

B. bigemina (Smith and Kilb.) (Fig. 70). The cause of Texas fever

in cattle, the tick involved being Margaropus (Boophilus) annulatus.

c

finally breaks up into
about 8 spores (F),
the whole process oc-
cupying 72 hours.

Fig. 70 — Babesia 'bige-
mina (Doflein). The 8 cir-
cles represent blood corpus-
cles containing the parasite.

SUBCLASS 2. NEOSPORIDIA.

Sporozoa which form sporocysts throughout life, the entire cell not
being used in the formation of spores: 4 orders.
Key to the orders of Neosporidia here described :

«i In the organs of fishes and insects 1. MYXOSPORIDHDA

at In the muscle fibres of vertebrates 2. SABCOSPOBIDIHV

48

PROTOZOA

ORDER 1. MYXOSPORIDHDA *

Sporozoan parasites which occur in various organs of fishes, insects,
and other animals; body amo3boid or spherical and multinuclear ; sporu-
lation gives rise to sporoblasts in each of which one to several spores
develop: 4 families, including some dangerous parasites, one of which
is Glugea bombysis, the silk-worm parasite, which in thirteen years
previous to 1867 caused a loss in France of one billion francs.

FAMILY MYXOBOLIDAE.

Parasites of fishes rarely found in the amoeboid form, but usually
as cysts filled with spores in which are vacuoles which are stained
reddish brown by iodine: 3 genera.

MYXOBOLTJS Biitschli. Spores ovoid or elliptical: about 40 species.

M. lintoni Gurley. In all the tissues of Cyprinodon variegatus.

ORDER 2. SARCOSPORIDIIDA.

Sporozoan parasites in the muscle fibres of
vertebrates; body elongate forming cysts with a
double membrane, in which are spores: 1 genus.

2. SARCOCYSTIS Lankester. Elongated Sporo-
zoa living in the muscle fibres of the pig, sheep, rat,
and other animals : about a dozen species.

S. miescheriana (Kiihn) (Fig. 71). Length of
cyst 3 mm.: in the pig.

CLASS 4. INFUSORIA.f

The Infusoria are distinguished by their defi-
nite body form, the outer surface of the body being
bounded by a firm cuticula, and by the possession
of cilia. These cilia are short hair-like pro-
jections of the ectosarc through the cuticula,
and in the various species may appear as rapidly
vibrating locomotory organs, or may be united
to form tentacles, spines, membranes, or suck-
ing tubes. The ectosarc is often highly specialized,
it contains large numbers of defensive organs
which are minute rods lying perpendicular to

Fig. 71 — Sarcocystia
miescheriana
(Doflein). A, a cyst;
B, a piece of pork
containing cysts.

In many forms
called trichocysts,

* "The Myxosporidia or Psorosperms of Fishes and the Epidemics Produced by
Them," by R. R. Gurley, Bull. U. S. Fish. Com., Vol. II, 1893.

t See "A Manual of the Infusoria," by W. S. Kent, 1881. "A Preliminary Contri-
bution towards a History of the Fresh-water Infusoria of the United States," by
A. C. Stokes, Jour. Trenton Nat. Hist. Soc., Vol. 1, p. 71, 1888.

INFUSORIA 49

the surface which may be shot out into the water. In a few
forms (Vorticella] nettle organs are present. The ectosarc often con-
tains muscle ridges called myonemes, which appear as parallel longi-
tudinal or spiral lines, and in a few cases (Stentor) striated muscle
fibrillae are present. The entosarc is more fluid than the ectosarc and
is granular and contains a variety of specialized structures. Chief of
these are the nuclei, of which two kinds are present, the micronucleus
and the macronucleus. The latter is of large size and often branched
or irregular in shape, and is supposed to be vegetative in function.
The very much smaller micronucleus, of which more than one may be
present, lies alongside the macronucleus and is chiefly concerned with
reproduction and conjugation. The entosarc also contains one or more
contractile vacuoles and food vacuoles. The former have a definite
position in the body and serve to eliminate the water taken in with the
food vacuoles together with the excretory wastes. The food vacuoles
are globules of water which are taken into the entosarc together with
the food.

The food of Infusoria consists of organic particles of all sorts:
some live principally on animal food, some on plant food, many are
scavengers, and a few are parasitic. In all, with the exception of
certain parasitic forms, mouth and gullet are present: an oral groove
may lead to the mouth. The anus is usually a temporary opening.

The Infusoria reproduce by division, the animal in most cases
dividing into two equal parts. In some forms division takes the form
of budding. Conjugation takes place in all Infusoria. The two conju-
gating individuals fuse, in most cases temporarily by the ectosarc of
the mouth region, and an interchange of micronuclear substance takes
place. The macronucleus disintegrates in each animal while the micro-
nucleus divides several times. The products of these divisions disin-
tegrate, with the exception of a single one, which divides again. Of
the two micronuclei thus obtained in each of the conjugating individ-
uals, one migrates across to the other individual and fuses with the
micronucleus remaining there. This fusion micronucleus then divides
and a portion of it enlarges to form a new macronucleus. Where more
than one micronucleus is present, it is probable that this process goes
on with all of them. All Infusoria encyst themselves at certain times,
in which condition they may be carried by the wind long distances. The
Infusoria are found in both fresh and salt water. The name originated
with Ledermiiller in 1763 and was at first applied to all minute organ-
isms which may appear in infusions. Only in modern times has its
use been confined to protozoans. The class, contains about 1,200 species
grouped in 2 subclasses,

50 PROTOZOA

Key to the subclasses of Infusoria:

Oj Cilia present 1. CILIATA

o2 No cilia present in the adult, but long sucking tubes 2. SUCTOEIA

SUBCLASS 1. CILIATA.

Protozoa with cilia and usually with a definite mouth and gullet:
4 orders with about 1,000 species, of which about 400 are marine.
Key to the orders of Ciliata:

at Cilia usually, but not always, present on all parts of the body.

&! Cilia all approximately of the same length 1. HOLOTRICHIDA

62 Mouth surrounded by an adoral zone of large cilia 2. HETEROTRICHIDA

«2 Cilia present on only a part of the body.

&! Cilia confined to the ventral side 3. HYPOTRICHIDA

62 Cilia confined to one or more rings around the body 4. PERITRICHIDA

ORDER 1. HOLOTRICHIDA.

Protozoa in which the cilia are usually evenly distributed over the
body, with a tendency to arrange themselves in straight lines, which
have often a spiral arrangement; in the vicinity of the mouth the cilia
are often longer than elsewhere and in a few forms are confined to this
region; trichocysts almost always present: 10 families.

Key to the families of Holotrichida here described :

Ot Animals not parasitic.

&! Mouth closed except when taking in food, and without undulating membrane.
G! Mouth terminal or subterminal.

d^ Body usually oval or cylindrical 1. ENCHELINIDAE

d2 Dorsal side arched ; forward end often neck-like 2. TRACHELINIDAE

c2 Body ovoid ; mouth in middle or posterior region .... 3. CHLAMYDODONTIDAE
Z>2 Mouth always open and ventral with an undulating membrane around it or

in the gullet.
cx Oral groove absent or slightly developed.

di No equatorial zone of cilia 4. CHILIFERIDAE

d2 Broad equatorial zone of cilia 5. UP.OCENTRIDAE

c2 Long oral groove present.

dt No undulating membrane along oral groove 6. PARAMECIIDAE

d2 An undulating membrane along the oral groove 7. PLEURONEMIDAE

o2 Animals parasitic ; mouth absent 8. OPALINIDAE

FAMILY 1. ENCHELINIDAE.

Usually oval Infusoria, sometimes with a long slender forward por-
tion, with a terminal mouth by which large objects are swallowed, food
not being introduced in currents, as the gullet is never ciliated: about
18 genera; principally in fresh water.

INFUSORIA 51

Key to the genera of Enchelinidae here described:

cti Cilia cover whole body.
&! Body not covered with rectangular plates.
Cj Body not elongate and contractile.
di Gullet absent or short.
d Posterior bristle not present.

/! Mouth terminal ; body ovoid 1. HOLOPHEYA

/2 Mouth subterminal ; body with slight neck 2. ENCHELYS

ez Posterior bristle present 3. UBOTBICHA

d2 Gullet long and lined with a membrane 4. PBOBODON

c2 Body elongate and contractile.

dx Body flask-shaped with contractile neck 5. LACBYMABIA

d2 Body very long and contractile 7. TBACHELOCEBCA

62 Body covered with rectangular plates 6. COLEPS

a2 Cilia confined to 1 or 2 girdles.

&! Deep equatorial furrow present 8. MESODINIUM

&2 No such furrow 9. DIDINIUM

1. HOLOPHRYA Ehrenberg. Body striated, cylindrical or ovoid;
ciliation uniform ; no trichocysts : 6 species ; in fresh and salt water.

Fig. 72 Fig. 73 Fig. 74

Fig. 72 — Holophrya discolor (from Bronn). Fig. 73 — EncJielys pupa (Conn).
Fig. 74 — Urotricha fareta (Conn).

H. discolor Ehr. (Fig. 72). Body ovoid; length .04 mm.: in standing
water.

2. ENCHELYS 0. F. Miiller. Anterior end somewhat elongated and
truncated with subterminal mouth: 5 species; in fresh and salt water.

E. pupa Ehrenberg (Fig. 73). Body ovoid; length .08 mm.; color
often greenish.

3. UROTRICHA Claparede and Lachmann. Like Holophrya, but with
a bristle at hinder end: 2 species; in fresh water.

U. fareta Cl. and Lach. (Fig. 74). Springs with its bristle; length
.02 mm.

4. PRORODON Ehrenberg. Body ovate or ellipsoid, with a long
gullet lined by a membrane: 8 species; in fresh water.

P. griseus Claparede and Lachmann. Length .25 mm.: in standing
water.

5. LACRYMARIA Ehrenberg. Body flask-shaped, with a contractile
neck and spiral striations : 4 species ; in fresh and salt water.

52

PROTOZOA

Fig. 75

Lacrymaria olor
(Conn).

Fig. 76

Coleps hirtus
(Conn).

L. olor (0. F. Miiller) (Fig. 75). Body extremely
elastic, colorless or green ; length without neck .2 mm. ;
neck may be much longer than body: in fresh water.

L. lagenula Claparede and Lachmann. Body flask-
shaped, with a short conical neck which has a crown
of longer cilia; length up to .16 mm.: in decaying
marine and fresh-water algae.

6. COLEFS Nitzsch. Barrel-shaped,
rigid, with an armor composed of rect-
angular plates between which the cilia
project: 3 species; in fresh water.

C. hirtus Ehrenberg (Fig. 76). Gray
or green; length .04 mm.: in swamps.

7. TRACHELOCERCA Ehrenberg. Body
very long, slender, and contractile: ma-
rine; 1 species.

T. phcenicopterus Cohn (Fig. 77).

Length up to 1.7 mm.; with a four-sided mouth, which may not be
seen : Woods Hole.

8. MESODINITTM Stein. Body globular or conical, with a deep furrow
around the middle from which spring one or more rows of cirri; 4 con-
tractile tentacles in the mouth: 3 species; in fresh and salt
water.

M. cinctum Calkins (Fig. 78). Cirri projecting forward
number about 30: marine; Woods Hole.

9, DIDINIUM Stein. Body cylindrical, with 1 or 2
girdles of cilia and with a horseshoe-shaped macronucleus ;
forward end a projecting cone with the mouth at the tip:
2 species; in fresh water.

D. nasutum* (0. F. Miiller) (Fig. 79). Length. 1 mm.:
feeds on Paramecium and
other large infusorians.

FAMILY 2.
TBACHELINIDAE.

Dorsal side of body
arched ; mouth terminal
or subterminal, usually
at the end of a long
neck: 6 genera.

Fig. 77

Fig. 78

Fig. 79

(clSSs).

Fig. 78 — Mesodinium cinctum
(Calkins). Fig. 79 — Didinium
nasutum (Mast).

* See "The Reactions of Didinium nasutum," etc., by S. O. Mast, Biol. Bull.,
Vol. 16, p. 91, 1909.

INFUSOEIA

53

Key to the genera of Trachelinidae here described :

ox Distinct neck region.
6X Mouth runs the length of the neck.

Ci Entire body uniformly ciliated 1. AMPHILEPTUS

c2 Ventral surface only ciliated 2. LIONOTUS

&, Mouth at base of neck, which is very long 4. DILEPTUS

a, No distinct neck region 3. LOXOPHYLLUM

1. AMPHILEPTUS Ehrenberg. Body often curved, elongate, flattened,
with a sharp neck-like forward end; no gullet: 3 species; in fresh and
salt water.

A. gutta Claparede (Fig. 80). Macronucleus double; length .08 mm.

Fig. 81

Fig. 80 — Amphileptus gutia
(Conn) . Fig. 81 — Lionotus fas-
ciola (Calkins). Fig. 82 — Loxo-
phyllum rostratum (Conn).

Fig. 80

Fig. 82

2. LIONOTUS Wrzesniowski. Body elongate, tapering to both ends,
with a large hump ; usually two macronuclei ; flattened side only ciliated ;
anterior end neck- like : 6 species ; in fresh and salt water.

L. wrzesniowskii Kent. Length .18 mm. : in fresh water.

L. fasciola (Ehrenberg) (Fig. 81). Body ellipsoid, hinder end
conical; length up to .6 mm.: in fresh and salt water; Woods Hole; Cold
Spring Harbor.

3. LOXOPHYLLUM Dujardin. Body flat, with a broad hyaline border ;
anterior projection slight, turned to the right; trichocysts often in
papilla-like groups; nucleus often bead-like: in standing water; 4
species; in fresh and salt water.

L. rostratum Cohn (Fig. 82). Body elongate;
length .15 mm. : in fresh water.

L. setigerum Quennerstedt. Body broad; 1
mm. long: in salt water.

4. DILEPTUS Dujardin. Body large, elongate, with a long contractile
neck, at the base of which is the mouth ; numerous contractile vacuoles ;
nucleus often bead-like : 2 species ; in fresh and salt water.

D. anser (O. F. Miiller) (Fig. 83). Body striated; length up to
1.5 mm.: among algae in fresh water.

Fig. 83 — Dileptus anser
(Conn).

54

PEOTOZOA

FAMILY 3. CHLAMYDODONTIDAE.

Ovoid or kidney-shaped Infusoria with the mouth usually some dis-
tance from anterior end; gullet specially modified to swallow food of
large size: about 11 genera.

1. NASSULA Ehrenberg. Body ovate or cylindrical; mouth between
middle and anterior end; gullet armed with rods or with a membrane:
8 species; in fresh and salt water.

N. ornata Ehr. Body nearly circular, usually with brightly colored
spots; gullet with rods; length .2 mm.: in fresh water.

N. macrostoma Cohn (Fig. 84) . Body nearly circular, with brightly
colored spots; gullet with a membranous lining; length .05 mm.:
marine; Woods Hole.

2. CHILODON Ehrenberg. Body flattened, with convex dorsal side;

Fig. 84 Fig. 85 Fig. 86

Fig. 84— Nassula macrostoma (Calkins). Fig. 85 — Chilodon cucullulus (Calkins).
Fig. 86 — Frontonia leucas (Calkins).

mouth at or in front of middle of body; gullet armed with rods:
6 species; in fresh and salt water.

C. cucullulus (0. F. Miiller) (Fig. 85). Length .1 mm. or less;
body ovoid; forward end bent to the left: in fresh and salt water.

FAMILY 4. CHILIFEEIDAE.

Mouth never behind the middle and always open, with an undulating
membrane on the edge of it or in the slightly developed gullet:
9 genera.

Key to the genera of Chiliferidae here described :

«! Long ventral furrow leading back from the mouth 1. FRONTONIA

a2 No such furrow.

&! Caudal bristle present 3. UEONEMA

&2 No bristle.

Cj Body oval, symmetrical 2. COLPIDIUM

c2 Body rounded dorsally, straight ventrally 4. COLPODA

1. FRONTONIA Ehrenberg. Body large, ellipsoid or elongate and
contractile and colorless, or green or brown, with mouth near forward

INFUSORIA

55

end and an undulating membrane in the gullet: 3 species; in fresh
and salt water.

F. leucas Ehr. (Fig. 86). Body brown or black in color; length
.3 mm. or more; a furrow extends back from the mouth: in fresh and
salt water; Woods Hole.

2. COLPIDIUM Stein. Body oval, the ventral side being incurved
and the forward end smaller than the hinder; mouth central: 2 species;
in fresh and salt water.

C. colpoda (Ehrenberg) (Fig. 87). Length .045 mm. or more: in
fresh and salt water; common in infusions; Woods Hole.

3. URONEMA Dujardin. Body minute and oval, with a long bristle
at the hinder end; mouth near middle surrounded by membranes: 6
species; in fresh and salt water.

Fig. 87

Fig. 88

Fig. 89

Fig. 87 — Colpidium colpoda (Calkins). Fig. 88 — Uronema marinum (Calkins).
Fig. 89 — Colpoda cucullus (Conn).

U. marinum Duj. (Fig. 88). Length .05 mm.: in fresh and salt
water; in decaying vegetation; marine; Woods Hole.

4. COLPODA 0. F. Miiller. Body laterally compressed, with rounded
dorsal and straight ventral surface; mouth toward forward end, sur-
rounded by long cilia: several species; in fresh water, especially in hay
infusions.

C. cucullus Mill. (Fig. 89). Body ellipsoidal; length .1 mm.: in
fresh water; very common.

FAMILY 5. UKOCENTBIDAE.

Body barrel-shaped; mouth near the middle; a broad girdle of
longer cilia around the body: 1 genus.

UROCENTRUM Nitzsch. Characters as above : 1 species ; in fresh and
salt water.

U. turbo (0. F. Miiller) (Fig. 90). Length .06 mm.; swims with a
whirling motion.

FAMILY 6. PAEAMECIIDAE.

Body elongate, with a long, deep, oral groove leading to the mouth
which is in the middle or hinder part of the body: 1 genus; common in
infusions and decaying organic matter.

56 PEOTOZOA

PARAMECIUM* 0. F. Miiller. Slipper-animalcules. Characters as
above; trichocysts distinct; two contractile vacuoles: 4 species; in fresh
and salt water.

P. aurelia Mill. (Fig. 91). Forward end rounded; hinder end bluntly
pointed; length .15 mm.; 2 micronnclei: in fresh and salt water; common.

P. caudatum Ehrenberg (Fig. 92). Like P. aurelia, but somewhat
larger and more pointed behind and with 1 micronucleus : in fresh
water; commoner than the preceding.

Fig. 90 Fig. 91 Fig. 92

\trum turlo (Conn). Fig. 91 and Fig. 92 — Pan
and P. caudatum in outline (George T. Hargitt).

Fig. 90 — Urocentrum turbo (Conn). Fig. 91 and Fig. 92 — Paramecium aurelia

utlin

P. bursaria Ehr. Body wide, rounded, and obliquely truncate for-
ward and pointed or rounded behind; usually bright green from the
numerous green algae (zoochlorellae) in the ectosarc; length .12 mm.:
in fresh water.

FAMILY 7. PLEURONEMIDAE.

Body oval or ellipsoidal, with a long, deep oral groove leading to
the mouth in hinder part of body; along the edge of this groove is a
large undulating membrane: 5 genera.

Key to the genera of Pleuronemidae here described :

Oj No caudal bristle.

&! Hinder end acute 1. LEMBADION

62 Hinder end rounded 2. PLEURONEMA

o2 Caudal bristle present 3. LEMBUS

1. LEMBADION Perty. Body oval, rigid, posterior end acute: 1
species.

L. bullinum Perty (Fig. 93). Length .05 mm.: in fresh water.

2. PLEURONEMA Dujardin. Body rigid, oval, and flattened; oral
groove takes in a large part of the ventral surface and with a high, undu-
lating membrane ; cilia very long : 2 species ; in fresh and salt water.

P. chrysalis (Ehrenberg) (Fig. 94). Moves by springs and by swim-
ming; length .04 mm.: in fresh and salt water; in decaying vegetation.

* See "Races of Paramecium," by H. S. Jennings and G. T. Hargitt, Jour. Morph.,
Vol. 21, p. 495, 1910. "Two Thousand Generations of Paramsecium," by L. L.
Woodruff, Arch. f. Prot. Vol. 21, p. 263, 1911. "Paramaecium aurelia and P.
caudatum," by same, Jour. Morph., Vol. 22, 1911.

INFUSORIA

57

3. LEMBITS Cohn. Body elongate, with a long caudal bristle ; mouth
in the middle with the oral groove leading to it from the forward end:
in decaying plants; 3 species; marine.

Fig. 93

Fig. 94

Fig. 95

Fig. 93 — Lembadion tullinum (Conn). Fig. 94 — Pleuronema chrysalis (Calkins).
Fig. 95 — Lembus injusionum (Calkins).

L. infusionum Calkins (Fig. 95). Body lancet-shaped, with a taper-
ing anterior extremity; a row of contractile vacuoles extends from the
hinder end forward; length .07 mm.: Woods Hole.

FAMILY 8. OPALINIDAE.

Mouth absent; body oval or elongate: 6 genera, parasitic in the
Anura and in worms and mollusks.

1. OPALINA* Purkinje and Valentin. Elliptical Infusoria living
parasitic in the rectum of frogs and toads; 13 species.

O. ranarum Pur. and Val. (Fig. 96). Body flattened;
many contractile vacuoles; length .6 mm.: in frogs and
toads.

2. ANOPLOPHRYA Stein. Body elongate: in the di-
gestive tract of marine annelids and on the gills of
crustaceans; occasionally free-swimming.

A. branchiarum St. Length .1 mm.; body flask-
shaped: Woods Hole; free-swimming.

ORDER 2. HETEROTRICHIDA.

Body with uniform ciliation and an adoral zone along the oral
groove consisting of cilia fused together to form membranelles : 7 families.
Key to the families of Heterotrichida here described:

at Body not in a cup.
&! Body not with a crown of long cirri,
c?! Body not funnel or trumpet-shaped.

rf, Body elongated 1. PLAGIOTOMIDAE

d2 Body usually oval with a triangular oral groove 2. BURSABIIDAE

c2 Body funnel or trumpet-shaped 3. STENTOBIDAE

62 Body with a crown of long cirri 4. HALTERIIDAE

a2 Body in a cup 5. TINTINNIDAE

* See "Opalina," by M. M. Metcalf, Arch. f. Prot., Vol. 13, p. 195, 1909.

58

PROTOZOA

FAMILY 1. PLAGIOTOMIDAE.

The oral groove extends from the forward end of the mouth, near
the middle of the body; adoral zone along the left side of the groove;
body elongate: 6 genera.

Key to the genera of Plagiotomidae here described :

Oj Oral groove spiral 1. METOPUS

a2 Oral groove straight.

&! Forward end acute and turned to the left 2. BLEPHABISMA

62 Body straight and worm-like 3. SPIBOSTOMUM

Fig. 97

Metopus

sigmoidea

(Conn).

cylindrical,
tinct spiral

Fig. 98

Blepharisma
vndulans
(Conn),

1. METOPUS Claparede and Lachmann.
drical; oral groove extends spirally across
two-thirds of body; contractile vacuole at
2 species; in fresh and salt water.

M. sigmoides (0. F. Muller) (Fig. 97).
Length .13 mm.; body very contractile: in
fresh water.

2. BLEPHARISMA Perty. Forward end
acute and turned to the left; hinder end
rounded : several species ; in fresh water.

B. undulans Stein (Fig. 98). Length
.37 mm. ; color red : in fresh water.

3. SPIROSTOMTTM Ehrenberg. Body long,
and worm-like, very contractile, with dis-
striations; nucleus bead-like; oral groove in

about first third of body; contractile
vacuole at hinder end: 2 species; in fresh
and salt water.

S. teres Claparede and Laehmann
(Fig. 99). Length .4 mm.; body tapers
slightly at both ends; nucleus sometimes
simple.

S. ambiguum (Bory de Vincent). Body
1 mm. long or more, and not tapering.

Body cylin-
the forward
hinder end:

Fig. 99

Spirostomum

teres
(Conn).

FAMILY 2. BUESAEIIDAE.

Body usually oval and flattened, the oral groove being a triangular
sunken area ending in the mouth; adoral zone on left edge of groove:
5 genera.

Key to the genera of Bursariidae here described :

C4 Animals parasitic 2. BALANTIDIUM

«2 Animals not parasitic.

&! Body very broad 1. BURSABIA

&2 Body cylindrical . .3. CONDYLOSTOMA

INFUSOBIA

59

1. BURSARIA 0. F. Miiller. Body large, purse-shaped, obliquely
truncate in front; nucleus long, ribbon-like: 1 species; in fresh water.

B. truncatella Mill. (Fig. 100). Length 1 mm.
and more: often between fallen leaves in the
water.

2. BALANTIDITJM Stein. Body spindle-shaped,
with the oral groove at the apex : 4 species, para-
sitic in mammals, amphibians, and worms.

B. coli St. (Fig. 101). Length .12 mm.: in
the large intestine of the pig and man, causing
diarrho3a.

B. entozoon (Ehrenberg). Length .2 mm.:
in the large intestine of frogs, toads, and
salamanders.

3. CONDYLOSTOMA Dujardin. Body rounded or cylindrical, tapering
anteriorly with obliquely truncate forward end; nucleus bead-like: 2
species, in fresh and salt water.

C. patens (0. F. Miiller) (Fig. 102). Length .4 mm.; width .10
mm.: fresh and salt water.

Fig. 100

Bursaria truncatella
(Conn).

Fig. 101

Fig. 102

Fig. 103

Fig. 101 — Balantidium coli (Doflein). Fig. 102 — Condylostoma patens (Calkins).
Fig. 103 — Stentor coeruleus (Doflein).

FAMILY 3. STENTOBIDAE.

Body the shape of an elongated funnel and very contractile, the
small end of which can be attached; large end truncate, the adoral zone
passing around the edge; nucleus usually beaded: 2 genera; in fresh
water.

STENTOR* Oken. Fixed or free-swimming; when swimming body
is contracted and ovate: 8 species; in fresh water.

S. cceruleus Ehrenberg (Fig. 103). Body blue; length .25 mm.

* See "Selection of Food in Stentor coeruleus (Ehr.)," by A. A. Schaeffer, Jour.
Exp. Zool., Vol. 8, p. 839, 1910.

60

PROTOZOA

S. polymorphus (0. F. Miiller). Body usually green from the pres-
ence of algae (zoochlorellae) but sometimes colorless; length 1 mm.:
sometimes very abundant on water plants.

S. rceseli Ehr. Body colorless; nucleus ribbon-shaped; often
attached by a short case; length 1 mm.

FAMILY 4. HALTERIIDAE.

Body spherical or ovoid, often with long bristles and a few cilia
scattered over the body; animal moves by springing: 2 genera.

1. HALTERIA Dujardin. Body small, spherical,
with anterior adoral ciliated zone, and usually body
bristles: 2 species; in fresh water.

H. grandinella (0. F. Miiller) (Fig. 104).
Length .04 mm.

2. STROMBIDITJM Claparede and Lachmann. Like

Fig. 104—Halteria Halteria, but without the bristles: 6 species; in
grandinella (Broun). fregh and ^ water

S. caudatum Fromentel. Caudal appendage present; length .035
mm.: in fresh and salt water.

FAMILY 5. TINTINNIDAE.

Body attached by a stalk to a cup: 5 genera.

1. TINTINNOPSIS Stein. Animal in a chitinous
cup on which are embedded sand granules; anterior
end has two circles of cilia: numerous species;
marine.

T. beroidea St. (Fig. 105). Cup thimble-shaped;
length .05 mm.: Woods Hole.

T. davidom Daday. Cup elongate with a long
spine; length .23 mm.

2. TINTINNUS Ehrenberg. Like Tintinnopsis
except that no sand grains are imbedded in the cup :
numerous species; in fresh and salt water.

T. amphora Claparede and Lachmann. Length .1 mm.; cup elon-
gate: marine; Cold Spring Harbor.

Fig. 105 — Tintin-
nopsis beroidea
(Calkins).

ORDER 3. HYPOTRICHIDA.

Body flattened and with cilia, spines, cirri, and membranelles
confined to the ventral surface; dorsal surface may have bristles: 3
families.

INFUSORIA

61

Key to the families of Hypotrichida here described:

«! Body usually elongate and broad, with ventral cilia 1. OXYTRICHIDAE

oa Body more or less circular with very long bristles and cilia usually absent.

2. EUPLOTIDAE

FAMILY 1. OXYTEICHIDAE.

Body somewhat elongate with arched dorsal and flat ventral side,
the latter with cilia, bristles, etc.; mouth near the middle with an oral
groove running backwards : 21 genera ; in fresh and salt water.

Key to the genera of Oxytrichidae here described:

»! Several median longitudinal rows of continuous cilia.
&x Five or more rows of cilia.

cx Mostly fresh-water animals 1. UBOSTYLA

c2 Marine animals 2. EPICLINTES

&2 Less than 5 rows of cilia.

G! Neither anterior nor anal bristles ; body acute anteriorly . . 3. STICHOTRICHA
c2 Such bristles present ; body usually broad.

d^ Animals mostly marine 4. AMPHIBIA

d2 Animals mostly in fresh water.
€1 Two median rows of cilia.

/! Three anterior and no anal bristles 5. UBOLEPTUS

f2 No anterior bristles ; anal bristles present 7. HOLOSTICHA

e2 Three or 4 rows, body broad and rectangular. 6. ONYCHODROMUS

C2 No median rows of continuous cilia ; but marginal rows present.

61 No caudal bristles 8. OXYTBICHA

62 Three long caudal bristles 9. STYLONYCHIA

1. UROSTYLA Ehrenberg. Body flexible, elliptical,
with longitudinal striations and rows of cilia; oral
groove at forward end; 5 to 12 long anal bristles in
an oblique row, and 3 or more anterior bristles: 6
species; in fresh and salt water.

U. trichota (Stokes) (Fig. 106). Length .3 mm.;
5 anal and about 20 anterior bristles: in fresh water.

2. EPICLINTES Stein. Body flexible, elongate, the
forward half being ovate, the hinder end slender and
cylindrical; several longitudinal rows of cilia: 1
species; marine.

E. radiosa Quenner-
stedt (Fig. 107). Length

.045 mm.; 5 large bristles at Fig. wi—Epidintes radiosa

(Calkins).

Pig. 106

Urostyla trichota
(Conn).

forward end: Woods Hole.

3. STICHOTRICHA Perty. Body cylindrical and very contractile,
with acute forward end; oral groove extending back to middle of
body; 2 or 3 rows of cilia; color often green: 4 species; in fresh and
salt water.

S. secunda Perty (Fig. 108). Length .2 mm.: in fresh water.

62 PROTOZOA

4. AMPHIBIA Sterki. Body elongate and cylindrical and contractile,
with rounded ends and often tinged red or yellow; several anterior
bristles and 5 to 10 anal bristles; oral groove extends back to middle
of body : 7 species ; in fresh and salt water.

Fig. 108

Fig. 109

Fig. 110

Fig. lOS—Stichotricha secunda (Conn). Fig. 109 — Amphisia kessleri (Calkins).
Fig. 110 — Uroleptus longicaudatus (Conn).

A. kessleri (Wrzesniowski) (Fig. 109). Body wider anteriorly;
length .13 mm.: marine; Woods Hole.

5. UROLEPTTTS Ehrenberg. Body cylindrical or flattened and slen-
der with rounded anterior and acute posterior ends; 3 anterior and
no anal bristles; oral groove short; 2 continuous rows of median cilia:
5 species; in fresh and salt water.

U. longicaudatus Stokes (Fig. 110). Length .2
mm. : in fresh water.

6. ONYCHODROMTTS Stein. Body broad, somewhat
rectangular; 3 or 4 rows of ventral cilia; one row of
large cilia along the oral groove: 1 species.

0. grandis St. (Fig. 111). Length .35 mm.; width
.12 mm.: in fresh water; slow of movement.

7. HOLOSTICHA Wrzesniowski. Like Oxytricha
except that there are 2 rows of median cilia and no
anterior bristles.

H. vernalis Stokes. Body elliptical, rounded at
both ends; length .07 mm.: in fresh water.

8. OXYTRICHA Ehrenberg. Body elliptical, with a
row of cilia along each lateral margin and a mid-
ventral group of bristles, consisting of about 8 bristles along the oral
groove, about 5 in middle of the body, and about 5 anal bristles : several
species; in fresh and salt water.

0. pellionella (0. F. Miiller). Body elongate; length .09 mm.: in
fresh water,

Fig. Ill

Onychodromus

grandis
(from Bronn).

INFUSORIA

63

0. bifaria Stokes (Fig. 112). Body broad; length .2 mm.; bristles
in a single line: in fresh water.

9. STYLONYCHIA Ehrenberg. Body elliptical,
rigid; oral groove triangular or semicircular, reach-
ing middle of body ; cilia and bristles as in Oxytricha;
usually 3 long caudal bristles present:
6 species ; in fresh and salt water ; very
common, the animals often moving by
quick jerks.

S. pustulata Ehr. Body broad;
length .25 mm.; width .1 mm.: in
infusions.

S. mytilus (0. F. Miiller) (Fig.
113). Body broadest in front of
middle; length .3 mm.; in fresh
water.

Fig. 112

Oxytricha
Mfaria
(Conn).

Fig. 113

Stylonychia
mytilus (Doflein).

FAMILY 2. EUPLOTIDAE.

Cilia very little developed or absent; large bristles and spines char-
acterize the ventral surface; nucleus ribbon-shaped; body round or oval:
5 genera; mostly marine.

Key to the genera of Euplotidae here described :

«! No posterior hook-like projection at side of body.
&! Anterior bristles present.

cx About 9 anterior bristles 1. EUPLOTES

c2 About 6 anterior bristles 2. DIOPHBYS

62 No anterior bristles 3. URONYCHIA

o2 Posterior hook-like projection at side of body 4. ASPIDISCA

1. EUPLOTES Ehrenberg. Body oval
or round, either green or colorless; mouth
in the hinder half of body, a long arched
oral groove joining it with the front end
of the body; about 9 large bristles oppo-
site the groove and a similar number of
anal bristles : 5 species ; in fresh and salt
water.

E. charon (0. F. Miiller) (Fig. 114).
Length .045 mm.: in fresh and salt
water.

2, DIOPHRYS Dujardin. Like Euplotes except that about 6 anterior
and 8 anal bristles, all very long and thick, are present; movement rapid
and continuous, not by jumps: 2 species; marine.

D. appendiculatus Stein (Fig. 115). Length .05 mm.; Woods Hole,

Fig. 114

Fig. 115

Fig. 114 — <E uplot es chevron
(Calkins). Fig. 115—Diophrys
appendiculatus (Calkins).

PROTOZOA

3. URONYCHIA Stein. Like Euplotes except that no anterior and
about 10 great anal bristles are present; movement rapid, with frequent
jumps: 2 species; marine.

U. setigera Calkins (Fig. 116). Length .04 mm.:
common at Woods Hole.

4. ASPIDISCA Ehrenberg.
Body oval with a short oral
groove in the middle of the
body and a short posterior
projection at the side of
body ; about 8 thick, anterior,
and 6, or more, anal bristles:
in fresh and salt water.

A. hexaris Quennerstedt
(Fig. 117). Length .07 mm.;
6 anal bristles: Woods Hole.

Fig. 116

Fig. 117

Fig. 116 — Uronychia setigera (Calkins).
Fig. 117 — Aspidisca hexaris (Calkins).

ORDER 4. PERITEICHIDA.

Cylindrical or cup-shaped infusorians in which the body is without
cilia except those forming the adoral zone at the oral groove, and in
a few cases a zone at the hinder end ; most of them are sessile : 3 families.

Key to the families of Peritrichida here described:

«! Body attached by a broad sucking disc 1. LICHNOPHORIDAE

a2 Body usually attached by a slender stalk 2. VORTICELLIDAE

FAMILY 1. LICHNOPHOEIDAE.

Forward part of the body with an oval oral groove; the hinder
part stalk-like and broadened at the end to form a sucking disc
provided with a ring of cilia, by
which the animal fixes itself: 1
genus; marine; usually parasitic
on mollusks.

LICHNOPHORA Claparede.
Characters given above.

L. macfarlandi Stevens (Fig.

Fig. 118 — Lichnophora macfarlandi
(Calkins).

118). Length .08 mm.; the animal

moves about on its pedal disc: Woods Hole, on the egg capsules of

Crepidula and on annelids.

FAMILY 2. VOETICELLIDAE.

Body cup-shaped and cylindrical and, with one or two exceptions,
attached by a stalk at the hinder end.; oral groove circular, around the

INFUSORIA 65

edge of the cup; body very contractile; animals frequently colonial:
16 genera.

Key to the genera of Vorticellidae here described :

Oj Animals not sessile and without a stalk ; parasites or commensals on Hydra

and other animals 1. TBICHODINA

«2 Animals sessile and stalked and not parasitic, although often attached to other

animals.

&! Body not enclosed in a cup.
<?! Stalk long or short and not branched ; animals solitary.

di Stalk long and contractile 2. VOBTICELLA

d2 Stalk short and not contractile.
6i Oral disc acts like a cover (operculum) which may close the opening of

the cup 3. PYXIDIUM

ez No such cover 4. RHABDOSTYLA

c2 Stalk branched ; animals colonial.
dt Stalk contractile.
6j Each individual of the colony can contract independently.

5. CABCHESIUM

€2 The colony contracts as a whole 6. ZOOTHAMNIUM

d2 Stalk not retractile, but rigid.

e± No operculum 7. EPISTYLIS

e2 Operculum present 8. OPEBCULABIA

&2 Body enclosed in a transparent cup 9. COTHUB^IA

1. TEICHODINA Ehrenberg. Body short, cylindrical or disc-shaped
with a ring of cilia around the circular flat base; oral end also flat:
parasites or commensals on Hydra, planarians, and other small animals,
also on the gills of fishes, attaching itself by the sucker-like base or moving
over the surface of the body ; sometimes entopara-

sitic in the urinary bladder or intestine of fish or
amphibians; several species.

T. pediculus Ehr. (Fig. 119). Length .08
mm. : often common on Hydra.

2. VORTICELLA L. Body more or less bell-
shaped with the oral groove extending inwards Fig. 119 — Trichodina
from the rim and with a long stalk ; nucleus horse-
shoe-shaped; colorless or green or blue: many species; in salt and fresh
water, on plants and animals.

V. nebulifera Ehrenberg (Fig. 120). Body campanulate, some-
times green in color, .07 mm. long with a stalk 4 times as long : in clear
water.

V. campanula Ehr. The largest Vorticella, with a body .2 mm.
long or less, bluish in color, and a stalk several times as long, not
annulated: in fresh water, often in clumps on water plants.

V. convallaria L. Body annulated, .1 mm. long, with a long stalk:
in infusions. This animal is interesting because it was the first micro-
scopic animal discovered by Leeuwenhoek, who first saw it in April, 1675.

66

PROTOZOA

Fig. 120

Fig. 121

Fig. 120 — Vorticella nebulifera (from Bronn).
Fig. 121 — Vorticella patellina (Calkins).

V. patellina 0. F. Miiller (Fig. 121). Body not annulated, with a
very wide oral end ; length .05 mm. : in fresh and saltwater; Woods Hole.

V. marina Greef.
Body annulated, .035
mm. long : marine ;
Woods Hole.

3. PYXIDIUM Kent.
Stalk short and not
contractile; body elon-
gate and elliptical, with
a small oral end; oral
cilia on a disc called
the operculum which can
close down like a lid.

P. ramosa Stokes.
Length .15 mm.: in
fresh water.

4. RHABDOSTYLA Kent. Like Vorticella but with a short and non-
contractile stalk; body bell-shaped or elongate,

with small oral end.

R. brevipes (Claparede and Lachmann).
Length .1 mm. : in fresh water.

5. CARCHESITJM Ehrenberg. Richly branched
colonies which form visible grayish masses on
water plants and often animals; each individual
can contract independently: several species; in
fresh water.

0. polypinum (L.) (Fig. 122). Body broad
and funnel-shaped and 'about .1 mm. long: com-
mon in fresh and salt water.

6. ZOOTHAMNIUM Ehrenberg. Like Carche-
sium, except that the colony contracts as a whole:
several species, in fresh and salt water.

Z. arbuscula Ehr. Body more or less cyl-
indrical; length .05 mm.: on water plants in
fresh water.

7. EPISTYLIS Ehrenberg. Like Ehabdostyla,
but colonial; whole colony rigid: numerous spe-
cies; in fresh and salt water, often on small
animals.

E. flavicans Ehr. (Fig. 123). Body bell-shaped, .1 mm. long: in
fresh water.

Fig. 122

Carchesium polypinum
(Doflein).

INFUSORIA

67

Fig. 123 — EpistyUs flavfcans
(Conn).

Fig. 124

Cothurnia crys-

tallina
(Calkins).

8. OPERCULARIA Ehrenberg. Like Pyxidium, but colonial; whole
colony rigid: 8 species; in fresh water.

0. articulata Ehr. Body spindle-
shaped, truncate at lower end, and .05 mm.
long: on water beetles.

9. COTHURNIA Ehren-
berg. Body elongate and
enclosed in a colorless or
brownish cup, at the bot-
tom of which it is at-
tached and into which it
can retract; cup also at-
tached either directly or
by a short stalk: numer-
ous species; in fresh and
salt water.

C. crystallina Ehr. (Fig. 124). Length of cup .07 to .2 mm.: in
fresh and salt water; Woods Hole.

SUBCLASS 2. SUCTOEIA.

Usually sessile Infusoria which have no cilia as adults but are pro-
vided with long hollow tentacles adapted for sucking or piercing; they
attach the tentacles to other Infusoria and suck them out; some are
entoparasites in Infusoria: 8 families with about 200 species.

Key to the families of Suctoria here described:

G! Body globular, without a cup 1. PODOPHRYIDAE

«2 Body not globular.

&! Body usually in a cup at end of a slender stalk 2. ACINETIDAE

&2 Body without cup or stalk ; tentacles knobbed 3. DENDBOSOMIDAE

FAMILY 1. PODOPHRYIDAE.

Body globular and not in a cup ; stalked or
not, and with tentacles of different kinds, some
knobbed and some acute: 5 genera.

1. SPHJEROPHRYA Claparede and Lachmann.
Body spherical or ovoid and without stalk, with
knobbed tentacles radiating from all sides: free-
living in swamps and infusions or entoparasites
in Stentor, Paramecium, and other ciliates; 4
species.

S. magna Maupas (Fig. 125). Diameter .06 mm.: among water
plants.

Fig.

phrya magna
(Conn).

PEOTOZOA

2. PODOPHRYA Ehrenberg. Body spherical or ovoid and attached
by a stalk; tentacles knobbed and radiating in all directions, either in
groups or not : several species ; in fresh and salt water.

P. gracilis Calkins (Fig. 126). Diameter of body
.008 nun. ; stalk very long, measuring .04 mm.: in salt
water; Woods Hole.

3. EPHELOTA Wright. Body more or less spherical,
with a stalk; tentacles of two kinds, being either
pointed and used for piercing, or short and cylindrical
and used for sucking: 8 species; marine.

E. coronata Wr. (Fig. 127). Diameter of body
.09 to .2 mm.; stalk three times as long, and thickest
at the body: common at Woods Hole on campanula-
rians, hydroids, etc.

FAMILY 2. ACINETIDAE.

Body usually in a cup and usually stalked; ten-
tacles knobbed; reproduction by endogenous budding,
the spores being ciliated: 4 genera.

1. ACINETA Ehrenberg. Body in a cup with a
stalk: several species; in fresh and salt water.

A. divisa Fraipont (Fig. 128). Body .027 mm.
long and does not fill the cup; tentacles long; length of stalk .1 mm.:
common on Bryozoa at Woods Hole.

Fig. 126

Podophrya gra-
cilis (Calkins).

Fig. 127

Fig. 128

Fig. 129

Fig. 127 — Ephelota coronata (Calkins). Fig. 128 — Acineta divisa (Calkins).
Fig. 129 — Acineta tuberosa (Calkins).

A. tuberosa Ehr. (Fig. 129). Cup very delicate and often difficult
to see ; tentacles in usually two groups ; color yellow ; length of body .33
mm.: at Woods Hole, in salt water.

INFUSORIA

69

2. TOKOPHRYA Butschli. Body not in a cup but at the end of a
stalk: several species; in fresh and salt water.

T. quadripartita (Claparede and Lachmann). Body .1 mm. long: in
fresh water.

FAMILY 3. DENDROSOMIDAE.

Body without cup or stalk; tentacles
knobbed and arranged in groups; reproduction
as in Acineta: 3 genera.

1. TRICHOPHRYA Claparede and Lachmann.
Body irregular in shape and spread out; fre-
quently parasitic: in fresh and salt water.

T. salparum Entz. On the branchial bars
of Molgula: at Woods Hole; often common.

2. DENDROSOMA Ehrenberg. Colonial ani-
mals on long and branching stalks which spring
from a creeping base: 1 species.

D. radians Ehr. (Fig. 130). Colony up to 2 mm. high: in fresh
water.

Pig. 130 — Dendrosoma
radians (Doflein).

PHYLUM H.

CCELENTERATA.

The coelenterates are radially symmetrical animals which possess
but a single internal cavity and no ccelom (Fig. 131). This cavity is a
simple space in a more or less cylindrical body in the lowest coelenter-
ates, but in the larger ones it is often extensively branched. The body
wall is composed of three layers, (1) an outer cellular layer, the ectoderm
(Fig. 131), (2) an inner cellular layer, the entoderm, and (3.) a tissue
between them called the middle or supporting layer which is skeletal in
function.

This middle tissue in all ccelenterates but the CtenopJiora is pri-
marily non-cellular, being a secretion of the cellular layers, and is called

the mesoglea; in the simplest
cases (Hydrozoa] (Fig. 131, A)
it remains non-cellular, but in the
larger and more complex forms
(Fig. 131, B) it becomes cellular
through the migration of cells
into it from the ectoderm or
entoderm. In the Ctenophora the
middle layer is primarily cellular,
being a development of the em-
bryonic mesenchyme.
The coelenterates are the lowest many-celled animals and are with-
out most of the organs and tissues which characterize the highest ani-
mals. Sexuality is, however, fully developed in all of them, some being
hermaphroditic, but the majority being unisexual. Asexual reproduction
by fission or budding is also very general and leads to the formation of
extensive colonies. Very many exhibit the phenomenon of alternation
of generation, in which a sexual, often free-swimming generation alter-
nates with a sessile, usually colonial and asexual generation.

History.— This phylum was constituted in 1847 by R. Leuckart,
who separated the polyps, medusae and Ctenophora (Eschscholtz) from
the Zoophyta-Eadiata of Cuvier and his contemporaries and called them
the Ccelenterata. He showed that these animals should be included in

70

Fig. 131 — Diagram of a coelenterate,
with (A) a non-cellular and (B) a cellular
mesoglea. 1, ectoderm ; 2, entoderm ; 3,
supporting layer.

SPONGIARIA

71

one and the same phylum inasmuch as they are without a coelom and the
hydroid and medusa are usually but stages in the same life history, facts
the importance of which had only very recently begun to be understood.
Trembley (1744) introduced the term " polypus " because of the fancied
resemblance of Hydra to the octopus, the polyp of the ancients. The
term "medusa" was employed by Linnaeus and the older writers because
of the resemblance of the tentacles of many jellyfish to the snake-like
curls of Medusa.

The phylum is composed of 3 subphyla.

Key to these subphyla :

G! Sponges ; animals sessile, without tentacles ................. 1. SPONGIARIA

o2 Hydroids, jellyfish, corals, etc. ; no cilia or outer surface ; tentacles usually
present ................................................ 2. CNIDABIA

aa Ctenophores ; outer surface with 8 ciliated bands ; 2 tentacles or none.

3. CTENOPHOBA

SUBPHYLUM 1. SPONGIARIA.* (PORIFEEA.)

Sessile, aquatic ani-
mals, with but few spe-
cialized organs and tis-
sues, in which skeletal
fibres or spicules usually
form an important part
of the body. The animals
often live in colonies of
irregular form in which
the various individuals
are indistinguishably fused
with one another. Numer-
ous pores in the body wall
admit water into an in-
terior chamber called the
cloacal cavity, of which a
large opening called the
osculum furnishes an outlet. Sponges are without tentacles and motile
appendages of any sort and the adult forms have no locomotory
powers.

Fig. 132 — Diagrams of the 3 types of sponges
(Boas). A, ascon type; B, sycon type; C, leucon
type. 1, osculum ; 2, cloaca ; 3, pore canals ; 4
radial canal ; 5, flagellate chambers.

* See "Rep. of Invertebrate Animals of Vineyard Sound and Adjacent Waters," by
A. E. Verrill, Rep. of U. S. Fish. Com., 1871. "Poriferata," by A. Hyatt, Stand.
Nat. Hist., Vol. 1, 1888. "Spongiaires," by Delage et H6rouard, Traite" de Zool.
concrete, 1899. "Sponges," by E. A. Minchen, A Treatise on Zoology, 1900. "Sponges
Collected in Porto Rico," by H. V. Wilson, Bull. Fish. Com., Vol. 20, Pt. 2, p. 375,
1900. "Catalogue of Recent Marine Sponges of Canada and Alaska," by W. Lambe.
Ottawa Naturalist, Vol. 14, 1900. "Biological Survey of Woods Hole and Vicinity," by
F. B. Sumner and others. Bull. Bur. Fish., Vol. 31, 1913.

i

li

72 CCELENTEEATA

The simplest sponges (Fig. 132, A) are usually cylindrical struc-
tures, either colonial or not, in the walls of which are numerous pores
through which water streams into the cloacal cavity; the osculum is at
the free end of the body. The body wall is composed of three layers,
the outer ectoderm or dermal epithelium (Fig. 133,1), the middle skeletog-
enous layer or mesoglea containing the skeletal elements (2), and the
entoderm (3) consisting of peculiar cells called collar cells or choano-
cytes which line the interior cavity. Each collar cell is provided with a
single flagellum, the base of which is surrounded by a high ridge or
collar.

This simple structure is called the ascon type of sponge. Other
sponges have what is called the sycon type of structure (Fig. 132, B).
In this the middle layer is much thicker than in the aseon type and from
the central cavity numerous cylindrical diverticula called the radial
canals (Fig. 132, B, 4) extend into the walls, and communicate also with the
outside through pore canals (3). In these sponges the
collar cells are confined to the radial canals, the central
cavity being lined with a flattened epithelium. Still an-
other type of sponge (Fig. 132, C) is called the leucon
or rhagon type, in which the skeletogenous layer is still
Fig. 133 thicker than in the sycon type and the collar cells are

spong
fder

porting ?aySerP- ^ie Sreat majority of sponges belong to the leucon

3, entoderm. type; in these the middle layer constitutes by far the
greater part of the body of the animals.

The ectoderm forming the dermal epithelium in all sponges is a
single layer of flattened cells which in a few cases (Oscarella) is ciliated.
In many sponges the ectoderm is more or less glandular and in all it is
contractile, the contractile elements in it being elongated cells called
myocytes which form sphincters around the pores and oscula and often
also surround the cloacal and other cavities; the ectoderm is also some-
times sensitive.

The mesoglea varies much in thickness in different sponges, being
generally thin in the smaller and more primitive sponges and thick in
the higher and larger ones. It arises as a secretion of the ectoderm
and contains various cellular elements, and usually also calcareous
or silicious spicules, or horn-like fibres composed of a substance called
spongin.

The spicules are of a great variety of forms and fall into two gen-
eral groups which are called megascleres and microscleres (Fig. 134).
The former are usually elongate or radiate in form and are often bound

onge (Lenden- confined to widened portions of the radial canals called
derm the flagellate chambers (5).

SPONGIAE1A

73

together by spongin or connective tissue fibres or articulate together to
form a network, and constitute the supporting framework of the body.
The latter are minute flesh spicules of a variety of forms which are scat-
tered throughout the tissues.

The cellular elements of the mesoglea fall into two distinct groups:
(1) those which are derived from the ectoderm, and (2) the archeocytes.
The former migrate into it and are either scleroblasts which secrete the
spicules, the spongioblasts which secrete the spongin fibres, or the col-
lencytes or connective-tissue cells which are distinguished by their stel-
late form and thread-like pseudopodial processes. The archeocytes are
primitive cells derived from the blastomeres during development, which
perform a variety of important functions. They are amoeboid cells
which are nutritive in function, ingesting and digesting food, and also
supply a circulatory element in that they aid in distributing nutriment.
They also give rise to the reproductive elements — the spermatozoa, the
ova, and the gemmules.

The entoderm con-
sists uniformly of col-
lar cells in all sponges.
The flagella of these
cells do not act in
unison, but each for
itself, and have for
their main function the
creation of currents in
the water which bring
the animal food and

oxygen and carry away the wastes. The current thus produced enters
the pores, traverses the radial canals and flagellate chambers into
the cloaeal cavity and passes out again through the osculum. The
food consists of organic particles and minute animals and plants;
these are ingested and digested by the collar cells in the lower,
calcareous sponges, but in the greater majority of them principally by
the amoeboid archeocytes. No special excretory or respiratory organs
and no muscles, nerves or sense organs are present in sponges, although,
as we have seen, contractility is present in the ectodermal cells, and sen-
sitiveness to external stimuli is often noticeable.

Sponges have three methods of reproduction: (1) by budding, (2) by
the formation of gemmules, and (3) by sexual methods. Budding is
simply growth which results in the formation of new oscula, each oscu-
lum representing a new individual ; it is of very general occurrence. In
a few sponges the bud becomes separated from the parent sooner or

Fig. 134 — 'Spicules of sponges (Minchin).
scleres j B, microscleres.

A, mega-

74 CCELENTERATA

later and leads an independent life, but in most of them the buds are
indistinguishably joined together so that a colony results, the members
of which form a compact whole.

Gemmule formation occurs in all fresh-water and some marine
sponges and is a provision against cold weather in temperate regions
and in the tropics against desiccation. With the approach of the unfa-
vorable season, archeocytes migrate to one spot in the middle layer, the
cells of which secrete a capsule around them. When the sponge dies
the gemmule falls to the bottom and remains, in the case of the fresh-
water sponge, until the following spring, when the capsule bursts and
the archeocytes within move out and develop into a sponge. Many
fresh-water sponges live through the winter, however, notwithstanding
the formation of gemmules.

Some sponges are hermaphroditic, others are unisexual. No special-
ized sexual organs are present, the ova and spermatozoa developing from
the archeocytes. The ciliated larva swims actively about in the water,
but finally attaches itself and after a metamorphosis develops » into the
adult animal.

Sponges are world-wide in their distribution and, with the exception
of the Spongillidae, are all found in the sea, where they range from
tide lines to very great depths. The fresh-water sponges occur in lakes
and streams in all countries.

History. — Aristotle was acquainted with sponges and knew that
they were animals, although he notes their likeness to plants. Through
the ages following his times, opinions differed concerning them, some
people believing them to be plants, others animals, while many ascribed
both an animal and a plant nature to them. Ellis (1765) first described
the currents of water which stream into and out of sponges. Lamardk
classified them with polyps. Robert Grant (1825) definitely proved
their animal nature, showing that water flowed into the sponge through
numerous minute pores and out through the oscula, and he correctly
inferred that ciliary action caused the flow. Many competent natural-
ists, however, still believed them to be plants, and the question was not
finally settled until about 1870 or later. H. J. Clark (1866) first demon-
strated the collar cells and laid the foundation for the belief which pre-
vailed for some time that sponges are colonial flagellate Protozoa. The
embryological investigations of F. E. Schulze and others, however, have
tended to overthrow this belief, and sponges are at present usually
classified under the Metazoa either as a separate phylum or under the
Coelenterata.

The Spongiaria include about 2,500 living and a large number of
fossil species, and are grouped in 3 classes.

SPONGIARIA 75

Key to the classes of Spongiaria:

ox Small marine sponges with calcareous spicules and large collar cells and

mostly under 2 cm. in length 1. CALCAEEA

o2 Usually larger sponges with silicious spicules or spongin fibres, or both, or
without either.

&! Glass sponges ; spicules usually six-rayed 2. HEXACTINELLIDA

62 Massive sponges without six-rayed spicules ; skeleton of silicious spicules,
spongin or both, or wanting 3. DEMOSPONGIAE

CLASS 1. CALCAREA.*

Marine sponges of small size with 1-rayed, 3-rayed or 4-rayed cal-
careous spicules; most of them are cylindrical in shape, colorless, either
solitary or colonial, and live in shallow water: 2 orders with about 150
species.

Key to the orders of Calcarea:
Oi Body wall thin and porous ; central cavity lined with collar cells.

1. HOMOCCELA

Oo Body wall not thin ; central cavity without collar cells 2. HETEROCCELA

ORDER 1. HOMOCCELA.

Very simple, thin-walled sponges in which the central cavity con-
tains the collar cells; each pore in the body wall is a perforation of a
single thickened dermal cell leading into the cavity : 2 families and over
50 species.

FAMILY LEUCOSOLENIIDAE.

With the characters given above; no radial canals or flagellate
chambers; with straight, triradiate, or quadriradiate spicules: 4 genera.

• 1. LEUCOSOLENIA Bowerbank. Usually
colonial, although sometimes simple
sponges, consisting of a mass of narrow
anastomosing tubes: numerous species.

L. botryoides Bow. (Fig. 135). Sponge
up to 35 mm. long, ivory white in color, and
consisting of a mass of slender tubes;
spicules 1 and 3-rayed and faint yellow in
color: in shallow water; Martha's Vine-
yard to Gulf of St. Lawrence; Europe. Fis- 1305

L. cancellata Verrill. Sponge massive,

consisting of small anastomosing tubes, up to 3 cm. in length and yel-
lowish in color: walls thin, with triradiate and quadriradiate spicules:
Casco Bay to Arctic Ocean.

* See "Die Kalkschwamme," by E. Haeckel, 1872.

76

CCELENTEEATA

L. fragilis* Haeckel (Ascortis fragilis Haeck.). Color white or yel-
lowish; spicules both straight or somewhat arched and triradiate; sep-
arate individuals 1 to 1.5 mm. long; colony 5 to 10 mm. in diameter: in
shallow water from Long Island Sound to Gulf of St. Lawrence;
common; Europe.

ORDER 2. HETEROCCELA.

Small sponges usually more or less cylindrical in form with thick
walls and a cloacal cavity lined with a flat epithelium and not with col-
lar cells, the latter being confined to more or less well-defined chambers
or in radial tubes which are joined by means of small inhalent dermal
canals with the outside ; either solitary or colonial : 6 families and about
90 species.

FAMILY 1. GEANTIIDAE.

Radial tubes extending outwards from the cloacal chamber; distinct
and continuous layer (dermal cortex) peripheral to the radial canals; no

conspicuous quadriradial spicules lin-
ing cloacal cavity : about 13 genera and
40 species.

1. GBANTIA Fleming. Triradial
spicules filling mesoglea and projecting
into cloacal cavity; cortex thin: 20
species.

G. ciliata (Fabricius) (Fig. 136).
Solitary sponges, 12 mm. high and 3
mm. thick; 2 kinds of monaxial spic-
ules, a longer kind protecting the
osculum and a shorter in the cortex
protecting the inhalent canals: Rhode
Island to Greenland, from low water line to 60 fathoms; Europe; often
common.

G. canadensis Lambe. Body 3 mm. high and 1 mm. thick: Gulf of
St. Lawrence and northerly.

FAMILY 2. LEUCONIDAE.

Collar cells in spherical flagellate chambers from which branched,
exhalent canals extend to the cloacal cavity : 5 genera.

LEUCANDRA Haeckel. Spicules without regular arrangement: many
species.

Fig. 136— Orantia ciliata (Kellogg)

A, group of 3 individuals ; B,

longitudinal section.

* See "On the Spongiae Ciliatae," etc., by H. J. Clark, Mem. Bost. Soc. Nat. Hist.,
Vol. 1, p. 305, 1866.

SPONGIARIA

77

L. taylori Lambe. Sponge small, solitary, globose, 6 mm. high and
4.5 mm. thick, with thick walls and a narrow cloacal cavity; spicules
triradiate, with long monaxials protecting the osculum: Vancouver
Island.

FAMILY 3. AMPHOEISCIDAE.

Conspicuous subdermal quadriradiate spicules with elongated in-
wardly directed rays: 5 genera.

AMPHORISCTJS Haeckel. Cortex thin; spicules triradial and quadri-
radial: several species.

A. thompsoni Lambe. Gulf of St. Lawrence.

CLASS 2. HEXACTINELLIDA.* (TRIAXONIA.)

Glass sponges. Sponges with usually rather thin walls and a large
cloacal cavity giving them a more or less tubular or basket-like shape;
spicules silicious, consisting of 3 crossed axes making them either 6-rayed
or belonging to the 6-rayed type, and either soli-
tary or joined to form a continuous skeleton
which often has the appearance of spun glass;
cloacal cavity large and unusually more or less
cylindrical, usually with simple radial flagellate
chambers opening out from it, the wall of the
cloacal cavity, however, often folded and the
chambers branched: about 12 families.

FAMILY 1. EUPLECTELLIDAE.

Body elongate, usually curved or twisted;
spicules joined together forming a network;
upper end the larger with a terminal sieve-like
plate; lower end with usually a mass of long
silicious threads which fastens the animals in
the mud: several genera.

EUPLECTELLA Owen (Fig. 137). With the characters of the family:
several species.

E. suberea Wyville Thomson. Body a straight, cylindrical, slightly
swollen tube, 25 cm. long and 5 cm. in diameter: West Indies, in deep
water.

FAMILY 2. HYALONEMATIDAE.

Body globose, elongate or cup-shaped with a long stalk composed of
long twisted silicious strands; several genera.

HYALONEMA Gray. Body funnel or cup-shaped: several species.

* See "Report on the Hexactinellida," by F. E. Schulze, Chall. Rep., Vol. 21, 1887.

Fig. 137—Eupleotella
(from Weysse).

78 C(ELENTEEATA

H. longissimum Verrill. Length 40 cm. : in 60 to 95 fathoms off the
New England coast.

CLASS 3. DEMOSPONGIAE.

Usually massive and often brightly colored sponges with thick walls
and small round flagellate chambers connected by branched exhalent
canals with the cloaca! cavity; spicules very varied in form, being often
monaxonic and straight and needle-like, or tetraxonic with 4 crossed axes,
giving them 8 rays; spongin either present with the spicules or not, or
the fibres alone may be present or both be wanting : 4 orders.

Key to the orders of Demospongiae :

Oj Skeleton formed of tetraxonic silicious spicules of a variety of forms without
needle-like spicules and without spongin ; in rare cases no skeleton.

1. TETRACTINELLIDA

o. Skeleton of needle-like spicules with often others and with or without spongin
fibres 2. MONACTINELLIDA

oa Skeleton of spongin fibres alone 3. CEBAOSPONGIAE

o4 Skeleton entirely wanting 4. MYXOSPONGIAE

ORDER 1. TETRACTINELLIDA.*

Sponges with usually a hard outside crust or cortex containing
megascleres which form the principal framework of the body, micro-
scleres occurring throughout the mesoglea and being of a variety of
forms, but usually reducible to the tetraxonic type: 8 families and over
325 species.

FAMILY 1. THENEIDAE.

Body usually more or less mushroom-shaped with the osculum in the
center: 1 genus.

THENEA Gray. With the characters of the family: several species.

T. echinata Verrill. Body 5 to 10 cm. broad and not quite so high,
with a short, thick stalk; upper portion with radiating bundles of spicules
which project beyond the surface : New England coast north of Cape Cod.

FAMILY 2. GEODIIDAE.

Body globose with a thick crust, provided with masses of spherical
spicules: about 8 genera and 180 species.

G-EODIA Lamarck. Tetraxonic needles radially arranged and con-
fined to the periphery; oscula sieve-like, in groups; incurrent openings
also sieve-like and scattered : 70 species.

G. miiUeri (Fleming). Spherical or flattened in youth, later irregu-
larly lobed; diameter and thickness sometimes 30 cm.: cosmopolitan;
Jamaica; West Indies.

* See "Tetraxonia," by R. von Lendenfeld, Das Tierreich, 1903.

SPONGIAEIA 79

ORDER 2. MONACTINELLIDA.

Sponges in which the skeleton consists of needle-like (monaxonic)
spicules and sometimes other kinds, with or without spongin fibres: 20
families, grouped in 2 suborders, and numerous species, constituting the
majority of all sponges; mostly in shallow water; 1 family in fresh
water.

Key to the suborders of Monactinellida:

Oj Sponge compact, usually massive 1. HADROMERINA

»2 Sponge not compact, usually with spongin 2. HALICHONDBINA

SUBORDER 1. HADROMEBINA.

Body compact, having a hard outside crust or cortex, and usually
massive but sometimes cup-shaped or stalked; spongin absent or very
poorly developed: 8 families.

FAMILY 1. TETHYIDAE.

Body spherical, with slight projections on the surface caused by the
protrusion of the end of bundles of long needles (megascleres) without
heads which extend radially from . the centre of the body ; no spongin
fibres present: 6 genera.

TETHYA Lamarck. Body with a thick, leathery rind and the form
and color of a small orange : several species.

T. hispida Bowerbank. In 8 to 35 fathoms in Casco Bay, Maine.

FAMILY 2. SUBEEITIDAE.

Form massive; substance compact and firm; spicules (megascleres)
are needles with heads; without microscleres or spongin: 15 genera.

SUBERITES Nardo. Form various, often massive, sometimes pedun-
culate; outer surface smooth: 15 species.

S. compacta Verrill. Body irregular, being an elongated mass
attached by one edge ; length up to 15 cm. ; width and height 2 to 8 cm. ;
color bright yellow; surface smooth; oscula inconspicuous: Maine to
Virginia in shallow water ; often on the shells of hermit crabs.

FAMILY 3. POLYMASTIIDAE.

Form massive, often spherical, with long needles extending radially
from the centre; with the surface covered with small protuberances,
some of which have an osculum; no microscleres or spongin: 13 genera.

POLYMASTIA Bowerbank. Smaller needle and pin-shaped spicules
in addition to the radial ones present.

P. robusta Bow. Form irregular; color yellow or gray; diameter

80 CCELENTEEATA

up to 30 cm. ; with finger-like branches 4 to 10 mm. long : North Carolina
to Maine and northerly in 1 to 8 fathoms; very common in Long Island
Sound; Europe.

FAMILY 4. CLIONIDAE.

Sponges which bore in shells or limestone by some process not
understood; monaxial spicules of various forms: 4 genera.

CLIONA Grant. The sponge begins its existence by boring in the
dead or living shells of various mollusks; it honeycombs the shell, arid
after having destroyed it, grows over it, forming a mass often 15 or 20
cm. in diameter, on the surface of which are small elevations.

0. celata Grant. Sulphur sponge. Color bright yellow: very com-
mon from South Carolina to Maine in 1 to 12 fathoms; cosmopolitan.

SUBORDER 2. HALICHONDRINA.

Body not compact but usually fibrous, without a cortex; spongin
usually well developed: 13 families.

FAMILY 1. SPONGILLIDAE. *

Fresh-water sponges. Body variable in shape and forming an irreg-
ular mass incrusted on stones, sticks, plants, etc., up to the size of the
hand, or larger, and yellow or brown in color, or green where exposed to
the sunlight, as the result of the presence of zoochlorellae ; spicules of
two principal kinds, (1) the megascleres, slightly curved needles or rods
occurring in the mass of the sponge and (2) the microscleres, much
smaller needles, rods or amphidiscs (two star-like plates joined by a rod)
(Fig. 139, B) which occur in the sponge or form the shell of the gem-
mules; asexual reproduction by gemmules, these being globose buds
about .5 mm. in diameter, which may occur throughout the sponge, being
present mostly in the latter part of the summer and in the fall: about
10 genera and 50 species, of which 21 occur in this country; in fresh and
sometimes brackish water, both in running streams and in ponds and
lakes, from the surface to a depth of 200 feet; cosmopolitan.

Key to the American genera of Spongillidae:

«! Gemmules without tendrils or projections.

&! No amphidiscs present 1. SPONGILLA

62 Amphidiscs present.
Cj Discs of amphidiscs of same size.

d^ But one type of amphidiscs 2. EPHYDATIA

d2 Two types of amphidiscs 3. HETEROMEYENIA

c. Discs of unequal size 4. TUBELLA

a, Gemmules with tendrils or projections 5. CABTERIUS

* See "A Monograph of the Fresh Water Sponges," by E. Potts, Proc. Acad. Nat.
Sci., Phila., for 1887. "Spongillidae," by W. Weltner. Siissw. F. Deutschl., Heft
11), 1909.

SPONGIAEIA

81

1. SPONGILLA Lamarck. Gemmule without amphidiscs, but sur-
rounded by needles or rods alone; large needles usually smooth: 17
species, 6 American.

S. lacustris (L.) (Fig. 138). Sponge branching and usually green,
with smooth longer (megascleres) and rough shorter (microscleres)
needles; gemmules surrounded by spiny curved rods, but occasionally
without them, and often scarce until late in the fall: cosmopolitan, pre-
ferring running water and
sunlight ; the commonest
fresh-water sponge.

S. fragilis Leidy. Sponge
not branching, growing in
flat patches, usually yellow

or brown but occasionally
green in color; gemmules

A 6

abundant, in one or more ^g.

layers at the base of the

sponge; large needles smooth; no microscleres in body of sponge: in

standing and running water and avoiding the light; next to the above,

the commonest species.

2. EPHYDATIA Lamouroux (Heyenia Carter). Gemmule with amphi-
discs all of one type: 17 species, 8 American.

E. fluviatilis (L.) (Fig. 139). Sponge massive, occasionally lobate;
color yellow or brown, sometimes green; needles smooth
or rough with only the tip smooth; no smaller needles
present: cosmopolitan; in standing and running water,
preferring the former.

3. HETEEOMEYENIA Potts. Similar to
Ephydatia, but the gemmule has amphidiscs
of two different types, the less numerous
being much longer than the other and with
long hooked rays on the discs : 3 species, all
American.

H. ryderi Potts. Sponge massive,
often hemispherical, lobed, light green in
color; needles rough, except at the tips; long amphidiscs with spiny
shaft and discs consisting of 3 to 6 recurved hooks; short amphidiscs
with usually smooth shaft and large flat discs: eastern and central
North America, in shallow-flowing water.

4. TTJBELLA Carter. Discs of amphidisc of very unequal size, giv-
ing it the shape of a collar button; needles rough, sometimes with
rounded tips: 5 species, 1 American.

Fig. 139 — Ephydatia fluvia-
tilis. A, entire sponge attached
to a stick ; B, amphidiscs in
gemmule (Siissw. F. Deut).

82

CCELENTEEATA

T. pennsylvanica Potts. Sponge minute, being 6 mm. in diameter,
incrusting, gray or green in color; gemmules very numerous: eastern
North America, in shallow water.

5. CARTERIUS Potts. Aperture of gemmule with
a chitinous lining which is prolonged into a tube
which is expanded at its outer margin and often
divided into long tendrils: 5 species, 3 American.

C. tenosperma Potts (Fig. 140). Sponge yellowish-
green; needles rough, both long and short being pres-
ent ; gemmules with 3 to 5 twisted tendrils which may
be 12 mm. long; amphidiscs as in Ephydatia: eastern
United States; on water plants or shells.

Fig. 140

Portion of gem-
mule of Carterius

tenosperma
(Sussw. F. Deut.).

FAMILY 2. CHALINIDAE.

Form various ; usually branched ; spongin fibres often well devel-
oped; spicules needle-shaped; some species form gemmules like fresh-
water sponges: about 40 genera, all marine.

Key to the genera of Chalinidae here described :

d Spongin fibres form a regular network 1. CHALINA

Oz Spongin fibres little developed.

&! Spicules connected at their tips to form a network 2. RENIEBA

62 Spicules confusedly massed together 3. HALICONDEIA

1. CHALINA Bowerbank.
Sponges in which the spongin
forms a regular rectangular
network in which the spicules
are imbedded: several species.

C. oculata (Pallas) (Fig.
141). Finger sponge. Thick,
more or less flattened, forked or
digitate stalks with round ori-
fices 2 mm. in diameter scat-
tered over them; color orange
or red: very common from
Rhode Island to Labrador, in
1 to 80 fathoms.

C. arbuscula Verrill. Dead
men's fingers. Body a cluster
of branches, 10 to 20 cm. long
and 5 to 10 mm. in diameter, of
delicate texture and white or gray in color : North Carolina to Cape Cod
in 1 to 8 fathoms; very -common in Long Island Sound.

Fig. 141 — Chalina oculata (Shaffer).

SPONG1AEIA 83

2. RENIERA Schmidt. Form various, very fragile, easily pul-
verized; spongin very little developed; spicules straight needles
joined at their tips, and arranged to form a network: numerous
species.

R. mollis Lambe. Body massive, lobate, 9 cm. long, 5 cm. high and
3 cm. thick; oscula large, 5 mm. in diameter; surface rough; color yel-
lowish: Labrador; Vancouver.

3. HALICONDRIA Fleming. Massive sponges of various shapes with
needle-like spicules confusedly massed together, and with but little
spongin: numerous species.

H. panicea (Pallas). Color gray, yellowish or orange: from Rhode
Island to the Arctic Ocean, in 4 to 8 fathoms; Europe.

FAMILY 3. ESPEKELLIDAE.

Form various, a distinct network of spongin being present with
needles of various forms, one of which is C-shaped: numerous genera.

Fig. 142 Fig. 143

Fig. 142 — Microciona prolifera (Wilson). Fig. 143 — Stylotella heliophila (Parker).

1. ESPERELLA* Vosmaer. Amorphous sponges with needle-like spic-
ules predominating; spongin usually distinct: several species.

E. fibrexilis H. V. Wilson. Irregular sponges, yellowish-brown in
color, about 10 cm. in diameter, covered with algae, hydroids, etc.,
with a dermal membrane, beneath which are subdermal cavities;
spicules few; gemmules formed during the summer: Woods Hole, on
docks.

2. MICROCIONA Bowerbank. Sponge incrusting and irregular in
form, with straight or bent needle-like spicules and stout spongin fibres:
cosmopolitan.

* See "Observations on the Gemmule and Egg Development of Marine Sponges,"
by H. V. Wilson, Jour. Morph., Vol. 9, p. 277, 1894.

84 CCELENTERATA

M. prolifera (Ellis and- Solander) (Fig. 142). Bright-red sponges
incrusting on stones, shells, etc., when young, rising in digitate masses
sometimes 15 cm. high: South Carolina to Cape Cod from low water
mark to 10 fathoms; very common in Long Island Sound.

3. STYLOTELLA* Lendenfeld. Erect, inemsting sponges with very
little spongin and with needles in bundles ; no microscleres ; texture soft,
no hard rind present.

S. heliophila H. V. Wilson (Fig. 143). Yellowish sponges, either
massive or with erect finger-like processes, 5 to 10 cm. long and 5 cm.
high: common on stones and shells-in shallow water, North Carolina.

ORDERS. CERAOSPONGIAE.

Sponges in which the skeleton consists of a close network of spongin
fibres without proper spicules : 4 families and about 40 genera, which are
found in tropical and subtropical seas.

FAMILY 1. SPONGIIDAE.

Commercial sponges, f Spongin fibres solid, with a slender axial
core and frequently enclosing foreign bodies, such as sand; flagellate
chambers small with special openings by canaliculi into exhalent cavities:
7 genera and about 20 species, the fibrous skeleton of many of which is
used for commercial purposes.

1. ETTSPONGIA Bronn. Body massive with slender spongin fibres
and very small meshes; simple main fibres usually containing sand, the
finer connecting fibres without sand : about 12 species ; cosmopolitan.

E. officinalis (L.). Levant sponges. Fibres very elastic; form usu-
ally more or less globose, often lobed, cup-shaped or lamelliform; color
in life dark brown, being lighter beneath and on the sides : eastern Medi-
terranean; Bahamas; West Indies; Australia; in 1 to 100 fathoms;
several varieties are known, of which the most valuable is the light yel-
low cup-shaped E. mollissima from Asia Minor. The American variety,
the so-called glove sponge, is one of the least valuable commercial
sponges.

2. HIPPOSPONGIA Schulze. Horse sponges. Body massive and per-
meated by large, often cavernous canals; fibres delicate and forming
an irregular network: about 20 species.

* See "The Reactions of Sponges," etc., by G. H. Parker, Jour. Exper. Zool., Vol.
8, p. 1, 1910.

t See "Revision of North American Poriferae, Pt. I and II," by A. Hyatt, Mem.
Bost. Soc. Nat. Hist., Vol. 2, 1875 and 1877. "The Sponge Fishery and Trade," by
R. Rathbun, U. S. Com. of Fish., Sect. 5, Vol. 2, p. 817, 1887. "The Commercial Sponges
of Florida," by H. M. Smith, Bull. U. S. Fish. Com., Vol. 17, p. 225, 1897. "The
Commercial Sponges and Sponge Fisheries," by H. F. Moore, Bull. Bur. Fish., Vol. 28,
p. 403, 1910.

SPONGIARIA 85

H. gossypina Hyatt. Sheepswool sponge (Fig. 144). Form vari-
able; surface with numerous projections, between which are the large
oscula: Florida and the Bahamas; the most valuable American sponge.

H. equina Schmidt. Horse sponge; yellow sponge; grass sponge;
velvet sponge. Body massive, of coarse fibre and with extensive canal
system: Mediterranean; West Indies; Florida; much less valuable than
the above.

3. CACOSPONGIA Schmidt. Fi-
bres rather coarse and brittle ; main
fibres distinct from the connecting
fibres ; meshes large : several species.

C. spongeliformis H. V. Wil-
son. Body cylindrical, somewhat
branching, 25 cm. long, 7 mm.
thick; texture solid, with subder-
mal cavities; surface covered with
minute conical elevations; dermal
membrane with numerous shells,

sand, etc., imbedded in it: West Fi^ ^-HiP^Pongia goasypina

Indies.

4. HIRCINIA Nardo. Form variable, sometimes very large; charac-
teristic filaments present found in no other sponges, which are 3 or 4
mm. long, very fine and swollen at the ends: numerous species.

H. acuta Hyatt. Body 10 cm. high, massive, with several oscula;
surface with small protuberances; filaments in many places in bundles;
color gray, in life blackish : West Indies.

FAMILY 2. APLYSINIDAE.

Fibres hollow, without foreign inclusions; flagellate chambers small;
form various: 4 genera.

APLYSINA Nardo. Form various but usually digitate; fibres form a
close network; surface with protuberances: numerous species.

A. flagelliformis Carter. Body 10 cm. long, cylindrical, branching,
7 mm. in diameter, dark red in color: West Indies.

ORDER 4. MYXOSPONGIAE.

Sponges without skeleton of any kind : 2 families.

FAMILY HALISAECIDAE.

Slime sponges. Body incrusting and soft, with elongate, sac-like
flagellate chambers: 3 genera.

86

CCELENTERATA

HALISARCA Dujardin. Body small, soft and irregular, with large
oscula somewhat elevated: several species.

H. dujardini Johnston. Small, pale-yellow, gelatinous sponges grow-
ing on red algae: in 5 fathoms, off Rhode Island.

SUBPHYLUM 2. CNIDARIA.*

Jellyfish, hydroids, corals, etc. Aquatic animals, either sessile or
free-swimming, in which the body possesses a single internal cavity, the
gastrovascular space (Fig. 131). This has usually a single opening to
the outside, which is called the mouth, and is the common digestive and
circulatory cavity; in the simplest cases it is cylindrical in shape, but in
the higher and larger forms is much branched,
forming a system of canals.

The cnidarians are predacious animals and
usually possess long vibratile tentacles by means
of which they take their prey. These tentacles,
as well as other parts of the body, are provided
with numerous characteristic organs of peculiar
structure called the nettle organs or nematocysts
which render them effective instruments in the
performance of this important function. A nettle
organ (Fig. 145, 3) consists of a spiral, thread-like
tube with several barbs at the base which lies
coiled within a cavity in a specialized cell called

a cnidoblast (1). The cavity is filled with a poisonous fluid; its walls form
an ovoid sac, the outer end of which is continuous with the thread-like tube.
A minute spine, the cnidocil (2), projects from the free surface of the
cnidoblast into the water and when the surface of the ectoderm is irri-
tated, either by actual contact or in other ways, the tube is shot out with

* See "Contributions to the Natural History of the U. S.," Vol. 3 and 4, by L.
Agassiz, 1862. "Invertebrate Animals of Vineyard Sound," by A. E. Verrill, Rep. U. S.
Fish. Com., 1871. "Les Coelenteres," by Delage et He'rouard, Traite" de Zoologie
concrete, Vol. 2, 1901. "Hydroids of the Woods Hole Region," by C. C. Nutting,
Bull. U. S. Fish. Com., Vol. 19, 1899. "Synopsis of North American Invertebrates,
The Hydromedusae," by C. W. Hargitt, Part I, II, III, IV, Am. Nat., Vol. 35, pp.
301, 379 and 575, 1901, and Vol. 37, p. 331, 1903. "The Hydroids of the Pacific Coast of
North America," by H. B. Torrey, Univ. of Cal. Pub., Vol. 1, p. 1, 1902. "The Medusae
of the Woods Hole Region," by C. W. Hargitt, Bull. Bur. Fish., Vol. 24, p. 21, 1904.
"Notes on Crelenterates of Woods Hole," by C. W. Hargitt, Biol. Bull., Vol. 14, p. 95.
"A Synopsis of the Fixed Hydroids of New England," by J. S. Kingsley, Tufts College
Studies, Vol. 3, p. 13, 1910. "Medusae of the World," by A. G. Mayer, 1910. "The
Hydroids of the West Coast of North America," by C. M. Fraser, Bull, from the Lab.
of Nat. Hist, of Univ. of Iowa, Vol. 6, 1911. "Some Hydroids of Beaufort, North
Carolina," by C. M. Fraser, Bull. Bur. Fish., Vol. 30, p. 337, 1912. "A Biological
Survey of the Waters of Woods Hole and Vicinity," by F. B. Sumner and others, Bull.
Bur. Fish., Vol. 31, 1913.

'—-'I

Fig. 145 — Diagram of
a nettle organ in the ec-
toderm of a cnidarian
(Lendenfeld). 1, cnido-
blast; 2, cnidocil; 3,
nematocyst ; 4, nerve
fibre; 5, tactile cell.

CNIDARIA

87

Fig. 146 — The action of nettle
organs (Toppe). A, a nettle or-
gan piercing the chitinous shell
of an insect : B, nettle organs
holding a small crustacean by its
spines.

sufficient force to puncture the skin of small animals (Fig. 146)", and the
poisonous fluid which is thus injected into the wound may cause paralysis
or death. The thread tubes also often
lasso small animals by winding around
hairs and other projections of their
bodies (Fig. 146, B). The nettle organs
of the larger jellyfish often inflict a
painful wound to man.

The body of the Cnidaria is dis-
tinctly radiate in structure; in the
smallest jellyfish and hydroid polyps the
number of radii is usually four and in
the larger ones and the Alcyonaria, some
multiple of four; in the Zoantharia it is
usually six or a multiple of six.

Two distinctly different types of
structures are present among the Cni-
daria, which are, however, capable of
being referred to a common fundamental
form. These are: (1) the hydroid or
polyp type (Fig. 147, A), and (2) the medusa or jellyfish type (Fig. 147,
B, or Fig. 154). The first is seen in the simplest form in the fresh- water
Hydra and the hydropolyps, and in a more complex form in the corals ; in

these animals the body is
cylindrical in form, one end
is usually attached to some
more or less stationary ob-
ject, while at the other end
is the mouth surrounded by
tentacles.

Two variations of this
type are found. In the
Scyphozoa and the An-
ihozoa (Fig. 219) longitu-
dinal mesenterial ridges pro-
ject prominently into the
gastrovascular space and a
gullet lined with ectoderm
is present, while in the sim-
pler Hydrozoa or Hydro-
medusae these features are wanting (Fig. 147, A). Cnidarians of the
hydroid type live in colonies in the majority of cases which often con-

Fig. 147 — The two types of structure of cni-
darians. A, the hydroid type ; B, the medusa
type, a quarter of the animal being removed to
show the internal structure. (Delage et H6rou-
ard.) 1, mouth; 2, gastrovascular space; 3, ten-
tacle; 4, exumbrella ; 5, subumbrella ; G, manu-
brium ; 7, velum.

88 CCELENTERATA

tain thousands of individuals, and grow from one another by process of
budding.

The medusa type is seen in its simplest form in the usually minute
hydromedusans and in a more complex form in the larger scyphomedu-
sans. In all these animals the body is more or less bell or disc-shaped,
the convex side, which is called the exumbrella, corresponding to the
attached end of the hydroid polyp, while from the center of the concave
side, which is called the subumbrella, extends the manubrium, a more or
less cylindrical but often branched projection, at the end of which is
the mouth. Tentacles may be present on the manubrium, at the edge
of the bell, on the subumbrella or the exumbrella, and may be long or
short and flexible or rigid.

Two distinct types of medusae are met with. Those of one type are
called craspedote medusae (Fig. 147, B), because they possess a velum (7).
This organ is a ridge or membrane containing epithelial muscle fibres,
which extends inwards toward the manubrium from the entire edge of
the subumbrella. These medusae are almost all small, being usually less
than 2 cm. in diameter, although some are larger, JEquorea tennis attain-
ing a diameter of 10 cm. and ^Equorea forskalea of the Mediterranean
one of 40 cm. and, excepting the Narcomedusae, have a plain, unscalloped
edge. Those of the other type are called acraspedote medusae (Fig. 216) ;
these lack the velum or have it in a rudimentary form and possess a
scalloped outer edge, as well as other special features; they are also usu-
ally large, some having a diameter of a meter or more. A certain number,
however, are small, with a diameter of less than a centimeter.

In Hydra and the Anthozoa the hydroid or polyp type of structure
alone prevails, and the animals produce, either by budding or by sexual
methods, young individuals which develop directly into adults similar to
the parents. In most Trachomedusae and Narcomedusae, so far as known,
the medusa type alone prevails, the young developing directly into free-
swimming medusae. In the Hydromedusae and Scyphomedusae, on the
other hand, both types may prevail in the same species, and the phenome-
non of the alternation of generations is exhibited, an asexual generation,
which is the hydroid, producing by budding a sexual generation, which
in these animals is the medusoid generation. The medusoids are either
male or female and produce embryos called planulae, which after a period
of free life attach themselves to some fixed object and become hydroid
polyps, the medusoid buds, in certain cases, remaining attached to the
parent hydroid, and in others becoming free-swimming jellyfish.

In all the Cnidaria, the body wall consists of the outer ectoderm, the
inner entoderm and the middle mesoglea (Fig. 131). The ectoderm consists
of a single layer of cells, among the inner ends of which are small inter-

CNIDARIA 89

stitial cells and often epithelial muscle fibres aud nerve cells. The mes-
oglea is skeletal in function and a secretion of the two cellular layers;
in the Hydromedusae it remains non-cellular and usually thin, but in the
other Cnidaria, cells migrate into it from the ectoderm and it often be-
comes very thick, forming the jelly (Fig. 131, 3). The gastrovascular
space (Fig. 147) is cylindrical in the hydroid; in the medusa it is a
branched cavity which forms a system of canals. Food is taken into the
mouth ; in the gastrovascular space it is digested and the products of diges-
tion are caused to circulate throughout the body of the colony by the action
of the entodermal flagella or cilia. The sexes are separate in Cnidaria,
with some exceptions, but usually not dimorphic. The sex cells arise in
the ectoderm in the lower and in the entoderm in the higher forms.
Locomotion is accomplished by means of the muscle fibres which are the
inner projections of ectoderm or entoderm cells. The sessile hydroids
and Anthozoa move their tentacles about actively and can retract and
extend the body; the medusae swim slowly through the water by means
of the muscle fibres in the velum or in the subumbrella. The nervous
system consists of a plexus of nerve cells and fibres among the muscle
fibres, some of which, in the medusae, form a double ring in the outer
rim of the umbrella and in the acraspedote medusae a rudimentary gan-
glion at the base of each sense organ. The muscles may also be stimu-
lated directly and without the intermediary of nerve cells or fibres.
Special sense organs are absent in hydroids and the Anthozoa : in medusae
they are present in the margin of the umbrella and may be either visual
(ocellate) in function or equilibrial (vesiculate).

History.— Aristotle was acquainted with many cnidarians, especially
with actinians and medusae which he named Acalephae and Cnidae, the
latter term referring to the stinging power of the animals. During the
succeeding ages and down to about the middle of the eighteenth century
the animals were observed and figured by a number of naturalists, but
little or no exact knowledge of them existed. They were called either
plants or plant-animals (zoophytes) and were often considered the con-
necting link between the plant and animal kingdoms, a belief that has
not entirely disappeared in some localities even down to the present day.
Polyp stocks and corals were generally held to be plants, the individual
animals being called the flowers. When, however, Trembley in 1744
demonstrated the animal nature of Hydra and Peyssonnel in 1753 that of
corals, a new era began in the study of cnidarians, and in the following
years a large number of them were accurately figured and described by
Ellis, Pallas, O. F. Miiller, and others. The relation of the polyp to
the medusa was, however, still for a long time to be entirely unknown.
Cuvier in 1799 was one of the first to study the anatomy of the medusa

90 CCELENTERATA

and in 1812 brought polyps and medusae together in the single type-
group of Animalia-Radiata.

The next few years saw an immense increase in the knowledge of
both the anatomy of the medusa and the polyp and in the number of
the forms known, yet it was not until 1841 that M. Sars, on the basis
of his studies of Aurelia aurita, and 1842 that Steenstrup, on that of
his studies of Coryne, could first definitely formulate the principle of
the alternation of generations in cnidarians and elucidate the relation of
the polyp to the medusa. Even as late as 1837 Loven held the polyp and
medusa to be dimorphic sexual forms, the former being the male and
the latter the female individual. In 1847 Leuckart created the phylum
Ccelenterata and called attention to the fundamental sack form of the
body, and in 1849 Huxley showed that the walls of this sack were made
up of two layers which he named ectoderm and entoderm and homologized
with the two primitive germ layers of the higher animals. In 1851 Vogt
introduced the useful term Hydromedusa, Huxley in 1856 that of Hydro-
zoa, and Claus in 1891 that of Scyphozoa. The latest development of
the system is due to many authors, of whom perhaps Chun and A. G.
Mayer are especially to be mentioned. The first important American
work on cnidarians was J. D. Dana's Report of the Zoophyta of the
Wilkes Expedition (1846). Louis and Alexander Agassiz and their
pupils and followers have done the most to extend the knowledge of
American cnidarians. Mayer's monograph, The Medusae of the World,
is the most important recent work. The subphylum contains about 4,200
species, grouped in 3 classes.

Key to the classes of Cnidaria:

at Small hydroid polyps and both small and large medusae.
hi Hydroids without mesentarial rklges and usually colonial, and craspedote

medusae 1. HYDBOZOA (Hydromedusae)

&2 Minute hydroids with 4 mesentarial ridges, and acraspedote medusae.

2. SCYPHOZOA (Scyphomedusae)
a2 Corals, sea-anemones and gorgonians 3. ANTHOZOA

CLASS 1. HYDROZOA. (HYDROMEDUSAE.)

Hydroid polyps and craspedote medusae, usually with alternation of
generations. The hydroid stage, which is called the trophosome, is sessile
and usually colonial and produces by budding the medusoid stage, which
is called the gonosome. The latter is sexual and either male or female.
The individual hydroids are small, being usually but a few millimeters
in length, the solitary tubularians being exceptions, which may be several
centimeters, and in the case of the deep-sea Branchiocerianthus imperator,
which is allied to Corymorpha, a meter or more in length. The colonies
are often plant-like in appearance; the individual polyps are called the

HTDROZOA 91

hydranths (Fig. 152), the stalks on which they grow, the hydrocaulus,
and the root-like projections by which the stalk is attached to the sub-
stratum, the hydrorhiza. The gastro vascular space (Fig. 150) extends
throughout the colony so that all the polyps are in communication with one
another. A cuticular layer called the perisarc is secreted by the ectoderm
of many species which gives rigidity to the whole colony: in the Hydro-
corallinae the perisarc is calcareous and so enormously thickened that the
colony has the appearance of coral. The mouth of the hydroid is ter-
minal in position and at the summit of an elevation called the hypostome.

In very many Hydromedusae, the hydroid individuals are polymor-
phic (Fig. 162), being specialized to perform different functions.

The medusoid stage or gonosome is either a free-swimming craspedote
medusa or a sessile medusoid individual or gonophore which remains
attached to the parent hydroid. In the latter case it may have retained
the general form of a medusa or it may be reduced to the form of a bud
(sporosac) and have lost all semblance of the medusoid form. The
embryo is ciliated and is called the planula: after a period of free life
it attaches itself and becomes a hydroid polyp.

Most Hydromedusae live in the sea. Hydra is found in fresh water
and is cosmopolitan in its distribution. Cordylophora is a brackish water
form which also occurs in fresh water. A few medusae, Microhydra in
Pennsylvania and Europe, Craspedacusta (lAmnocodium) in America,
Europe and Brazil, Limnocnida in Lake Tanganyika and Holomisis in
Trinidad, occur in fresh water. The class contains about 2,000 species,
grouped in 7 orders.

Key to the orders of Hydromedusae:

A. THE HYDROIDS.

d Animals mostly in fresh water 1. HYDBABIAE

«2 Animals marine (rarely in fresh water).

&! Colony forms a coral-like stock 2. HYDROCORALLINAE

62 Colony not coral-like.

Ci Colony and individual hydroid usually not minute.
dv No protective cup (hydrotheca) on hydranth (Fig. 150) . .3. TUBULARTAE

d2 Hydrotheca present (Fig. 172) 4. CAMPANULARIAE

c2 Colony and hydroid minute (when present) 5. TRACHOMEDUSAE

c3 Colony free swimming , 7. SIPHONOPHORA

B. THE MEDUSAE.

(Excluding the Hydrocorallinae and the Siphonophora.)

0! Rim of umbrella not scalloped.

&! Gonads on manubrium 3. TUBULARIAE (Anthomedusae)

62 Gonads on subumbrella (sometimes also on manubrium).
d Medusae of ten disc-like at maturity. . .4. CAMPANULARIAE (Leptomedusae)

c2 Medusa usually hemispherical or elongate 5. TRACHOMEDUSAE

o2 Rim of umbrella scalloped 6. NARCOMEDUSAE

92

CCELENTEEATA

Fig. 148

Hydra viridissima
(Stissw. F. Deut.).
1, sperm ; 2, ovum.

ORDER 1. HYDRARIAE.* (THE HYDRAS.)

Elongate, cylindrical animals 1 to 3 centimeters in length. The animal
attaches itself temporarily by means of a sticky secretion at one end
which may be called the foot, and can move about slowly by gliding on
the foot and by a looping movement; it cannot swim. At the free end
is the mouth on the conical hypostome, at the base of
which is a single row of hollow tentacles. No perisarc
is present. The food consists of small crustaceans
and other animals which are caught by means of the
nematoeysts. When the animal is well fed it repro-
duces principally by budding, the buds often remain-
ing attached to the parent for a while, but finally
becoming separated: it also reproduces occasionally
by transverse or longitudinal fission. At certain times
the Hydra reproduces sexually and is either monoe-
cious or unisexual. Spermatozoa are produced from
specialized interstitial cells usually near the base of the tentacles which
form rudimentary testes, and a single large ovum may appear in an ovary
formed of interstitial cells usually near the proximal end of the body.

The order contains about four genera, of which Hydra
is the most familiar. The other genera, Protohydra and
Haleremita, which are marine, and Poly podium, which was
found on the eggs of the sturgeon in the river Volga, are
apparently rare and have not been found in this country.
HYDRA L. Tentacles 4 to 12 in number: 3 well
established species; cosmopolitan; in fresh water.

H. viridissima Pallas (H. viridis L.) (Fig. 148).
Green hydra. Body grass green, the color being due to the
presence of zoochlorellae in the entoderm; tentacles short
and about 6 in number; hermaphroditic: usually on water
plants.

H. oligactis Pallas (H. fusca L.) (Fig. 149). Brown
hydra. Body brown; tentacles very long and about 8 in
number ; proximal end of body slender and stalk-like ; unisexual : on stones,
sticks, and plants.

H. vulgaris Pallas (H. grisea L.). Color gray, orange, or brown;
proximal end of body not stalk-like; average number of tentacles 6: on
stones, plants, etc.

* See "M6m. pour servir a 1'Hist. d'un genre de Polyps d'eau douce," by A.
Trembley, 1744. "The Development of Hydra," by G. A. Tannreuther, Biol. Bull., Vol.
14, p. 261, 1908. "Die Benennung und Unterscheidung der Hydra Arten," by
A. Brauer, Zool. Anz., Vol. 33, p. 790, 1909.

Fig. 149

Hydra oligac-
tis (Stissw. F.
Deut.).

TUBULARIAE

93

ORDER 2. HYDROCORALLINAE.

Hydromedusans in which the polyps are colonial and have a calcified
perisarc of such thickness that the colonies resemble corals. In fact,
the animals were classified among the corals until Louis Agassiz in
1859 showed them to be hydromedusans allied to the Tubulariae. The
colony is incrusted on a rock or some other object and rises erect in the
form of a more or less arborescent, coral-like body in the water, being
composed of a network of tubes imbedded in a thick calcareous mass.
The tubes have the cellular structure characteristic of hydromedusans,
the calcareous groundwork being secreted by their ectoderm. Numerous
pores appear in the surface of the colony leading into cylindrical cham-
bers from the bottom of which two kinds of polyps may project into
the surrounding water; these are nutritive polyps or gastrozooids, with
mouth end often provided with tentacles, and the defensive polyps or
dactylozooids, without mouth and with batteries of nematocysts. The
gonosomes are usually sporosacs, but in a few forms they are medusae
and are produced in chambers which open to the outside through special
pores.

The suborder contains 2 families and 15 genera, which are inhab-
itants of tropical seas. One species occurs on the Florida coast.

FAMILY MILLEPOEIDAE.

Colony very varied in form, consist-
ing of a broad basal mass which is in-
crusted on the rock, and irregular, short
branches which rise from it into the
water; the nutritive polyps have each 4
or 5 short knobbed tentacles; the defen-
sive polyps are also provided with ten-
tacles ; the gonosome is a free medusa with
4 or 5 rudimentary tentacles: 1 genus.

MILLEPORA L. Each nutritive polyp
is surrounded by 5 to 6 long and very
contractile defensive polyps : 1 species on
the Florida coast and in the West Indies.

M. alcicornis L. Pepper coral. On
the coast of Florida; has unusual sting-
ing powers.

Fig. 150 — A tubularian hydroid
polyp ( Eudendrium ) ( Hertwig) .
1, entoderm ; 2, ectoderm ; 3, peri-
sarc ; 4, gastrovascular space ; 5,
mouth ; 6, hypostome.

ORDER 3. TUBULAEIAE. (GYMNOBLASTEA; ANTHOMEDUSAE. )

Mostly colonial hydromedusans in which the hydranth is without a
protective cup (hydrotheca) (Fig. 150) and which produce either free

94 CCELENTERATA

medusae or sessile medusoid buds. The medusae (Fig. 147, B) are known
as Anthomedusae and are usually more or less bell-shaped and ocellate and
bear the gonads on the inanubrium. Many of them have never been traced
to the hydroids which produce them : about 15 families.
Key to the families of Tubulariae here described :

A. THE HYDROIDS.

ai Hydranth without a basal whorl of tentacles, these being scattered more or
less irregularly over the hydranth.

&! Tentacles filiform ; no free medusae 1. CLAVIDAE

62 Tentacles knobbed 2. COKYNIDAE

a2 Hydranth with a basal whorl and with or without distal tentacles.
&! Hydranth with a basal whorl and no distal tentacles.
G! Colony arborescent.

rfj Hypostome conical ; free medusae present 3. BOUGAINVILLIIDAE

da Hypostome trumpet-shaped ; sporosacs present 4. EUDENDRIIDAE

c2 Colony not arborescent, but incrusting.

dt Sporosacs present and no free medusae 5. HYDRACTINIIDAE

dz Medusae present 6. PODOCOEYNIDAE

62 Hydranth with both basal and distal tentacles.

d Distal tentacles knobbed 7. PENNABIIDAE

c2 Distal tentacles filiform ; hydranths of large size.
di Free medusae present.

6j Hydranths solitary 8. CORYMORPHIDAE

63 Hydranths colonial 9. DENDROCLAVIDAE

dz Sporosacs in pendant clusters present 10. TUBULARIIDAE

B. THE MEDUSAE.

(The 1st, 4th, 5th and 10th families produce no free medusae.)

Oj No oral tentacles or lobes present.
&j Two or 4 marginal tentacles.

Cj Tentacles well developed 2. CORYNIDAE

ca Tentacles rudimentary 7. PENNARIIDAE

63 One long marginal tentacle, the others short (except Ectopleura).

8. CORYMORPHIDAE
c2 Oral tentacles or lobes present.
&! Marginal tentacles in 4 or 8 clusters (except Perigonimus).

3. BOUGAINVILLIIDAE
&2 Tentacles not in clusters.

d Marginal tentacles 2 or 4 PERIGONIMUS

c2 Marginal tentacles 4 or 8 6. PODOCORYNIDAE

c» Marginal tentacles numerous 9. DENDROCLAVIDAE

FAMILY 1. CLAVIDAE.

Trophosome : colony either branching or consisting of an extensive,
filiform hydrorhiza from which rise the polyps; hydranths elongate and
bearing numerous filiform tentacles irregularly placed. Gonosome : gono-
phores in clusters either just below the tentacles or on special branches
or even rising independently from the hydrorhiza, forming sporosacs and
never medusae: about 5 genera.

TUBULARIAE

95

Fig. 151 — Clava lep-
tostyla (Nutting).

Key to the genera of Clavidae here described :

ax Colony not branching ; polyps rising from a filiform hydrorhiza.

6j Sporosacs borne on hydranths 1. CLAVA

&2 Sporosacs spring from hydrorhiza 2. RHIZOGETON

a2 Colony branching 3. CORDYLOPHORA

1. CLAVA Gmelin. Simple unbranched hydranths rise from a fili-
form hydrorhiza; this is protected by a perisarc which extends a short
distance up the hydranth; sporosacs in clusters at

the base of the tentacles: 5 species.

C. leptostyla Agassiz (Fig. 151). Hydranths
reddish in color, about 2 cm. long, with about 20
tentacles; male sporosacs pink, female purple:
common in shallow water on fucus, piles, etc., from
Long Island Sound to Labrador; California.

2. RHIZOGETON Agassiz. Similar to Clava,
except that the sporosacs arise from the hydro-
rhiza on short stalks : 1 species.

R. fusiformis Ag. Hydranth about 8 mm.
high, with 12 tentacles; sporosacs shorter and
invested with the perisarc: in rock pools in Massachusetts Bay.

3. CORDYLOPHORA* Allman. Colony profusely branching, the hy-
dranths with scattered filiform tentacles being at the ends of the

branches ; sporosacs ovate,

L — / ffc springingfromthe

branches; with a definite
perisarc: 2 species.

C. lacustris All. (Fig.
152). Colony about 20 to
30 mm. high ; hydranth with
10 to 20 tentacles : on rocks,
eel grass, etc., in brackish
and fresh water, being one
of the very few fresh-water
coelenterates ; Rhode Island ;
Massachusetts ; Illinois ;
sometimes rather common;
Europe.

Fig. 152

Fig. 153

Fig. 152 — Cordylophora lacustris (Siissw. F.

Deut.). 1, hydranth; 2, hydrocaulus ; 3,

hydrorhiza. Fig. 153 — Syncoryne

mirabilis (Agassiz).

FAMILY 2. COEYNIDAE.

Trophosome: colony branched or not, with long, slender hydro-
eaulus and cylindrical hydranths bearing numerous knobbed tentacles

* See "Hydroids in the Illinois River," by F. Smith, Biol. Bull., Vol. IS, p. 67, 1910.

96

CCELENTERATA

irregularly placed. Gonosome: gonophores usually among the basal
tentacles and producing either free-swimming or attached medusae with
4 radial canals and 4 tentacles: numerous genera.
Key to the genera of Corynidae here described:

«! Hydroid branched; medusa with 4 long, marginal tentacles. . . .1. SYNCOBYNE
aa Hydroid branched ; medusa with 4 short knobbed marginal tentacles.

2. DIPUBENA

«3 Hydroid not branched; medusa with 2 long and 2 rudimentary marginal
tentacles 3. GEMMABIA

1. SYNCORYNE Ehrenberg. Hydroid colony 15 mm. high and branched
and with definite perisarc and an elongate, cylindrical hydranth; medusa
with an ocellus at the base of each tentacle : 16 species.

S. mirabilis Agassiz (Fig. 153). Hydroid col-
ony attached to seaweed, shells, etc., in shallow
water, from Martha's Vineyard to Greenland, also
in California; medusoid in 2 varieties, one, which
was first described as Sarsia mirabilis , free-swim-
ming, developing in early spring, 7 mm. high and
4 mm. in diameter, with 4 long, marginal tentacles
and a long manubrium extending beyond the velum
(Fig. 154) ; the other, a sporosac, with rudimentary
tentacles, and without ocelli or mouth.

2. DIPURENA McCrady. Hydroid like Syn-
coryne; medusae with 4 stout marginal tentacles
the ends of which are knobbed, and a long
manubrium with constrictions, often extending
beyond the velum: 6 species.
D. strangnlata McCr. (Fig. 155). Medusa very transparent, 3 mm.
wide, 4 mm. high, ovoid in shape: common at Woods
Hole; South Carolina.

3. GEMMARIA McCrady. Hydroid like Syncoryne
but unbranched, the hydranth rising from a creeping
hydrorhiza; medusa with 2 marginal tentacles, each of
which bears long-stalked nematocysts, and with mouth
without marginal lobes: several species.

G. gemmosa McCr. Hydroid on Mytilus shells,
etc.; adult medusa 6 mm. in diameter, almost spherical
and with 2 tentacles; no ocelli: Vineyard Sound and
southwards.

FAMILY 3. BOTJGAINVILLIIDAE.

Fig. 154— Syncoryne

mirabilis; medusa

(Hargitt).

Fig. 155

Dipurena stran-
gulata
(Hargitt).

Trophosome: colony branching with distinct, often annulated peri-
sarc; hydranth with a single whorl of filiform tentacles, Gonosome: a

TUBULARIAE

97

free-swimming medusa which is usually borne on the hydrocaulus and
has 4 radial canals; marginal tentacles either single or in clusters, and
4 or 8 manubrial gonads : about 19 genera.

Key to the genera of Bougainvilliidae here described:

&! Hydroid colony arborescent ; medusa with tentacles in clusters.
&! Medusa with tentacles in 4 clusters.
cx Medusa without short knobbed tentacles ; hydroid arborescent.

1. BOUGAINVILLIA

c2 Medusa with a pair of short knobbed tentacles at each cluster. .5. NEMOPSIS

&2 Medusa with tentacles in 8 clusters ; hydroid like Bougainvillia . .4. RATHKEA

o2 Hydroid colony with creeping hydrorhiza ; medusa with only 2 long tentacles.

&x Four short oral lobes 2. PERIGONIMUS

&2 Four long oral lobes 3. STOMOTOCA

1. BOUGAINVILLIA Lesson. Trophosome : col-
ony arborescent with a dense perisarc, hydranth
with conical hypostome. Gonosome: medusa
globular, with branching oral tentacles and 4
pairs at first and later 4 groups of marginal
tentacles: 20 species.

B. carolinensis (McCrady) (Fig. 156). Col-
ony may be 25 cm. high, usually 7 to 12 cm.;
hypostome conspicuous; tentacles about 12;
medusa with brick-red manu-
brium and black ocelli, 4 mm.
in diameter: Cape Cod and
southward; common on fueus,
piles, etc.

B. superciliaris Agassiz (Fig. 157). Colony 5 cm.
high or less; hypostome inconspicuous; tentacles 15 to
20; medusa with yellowish manubrium and black ocelli,
10 mm. in diameter: Newport to Greenland; on fucus
and shells; Europe.

2. PERIGONIMUS Sars. Trophosome : colony branch-
ing a little and rising from a reticulated hydrorhiza
with a gelatinous perisarc and conical hypostome.
Gonosome : medusa with 2 or 4 marginal tentacles ; no
ocelli: 10 species.

P. jonesi Osborn and Hargitt. Hydroid colony, 10
mm. high or less; hydranth with 16 tentacles; medusa
hemispherical with an apical projection, 2 mm. high and broad, with 2
long tentacles and 2 additional tentacular bulbs; manubrium short,
squarish, with 4 oral lobes: on spider crabs (Libinia) at Cold Spring
Harbor, L. I.

Fig. 156 — Bougainvillia
carolinensis (Hargitt).

Fig. 157

Bougainvillia

superciliaris

(Agassiz).

CCELENTEEATA

Fig. 158

Stomotoca

apicata
(Hargitt).

3. STOMOTOCA Agassiz. Trophosome like Perigonimus. Gonosorae:
medusa more or less conical with an apical projection ; with 2 long mar-
ginal tentacles and a squarish manubhum and 4 oral lobes
and the often very large gonads on the side: 6 species.

S. apicata (McCrady) (Fig. 158). Hydroid form
unknown; entoderm of manubrium greenish in color in the
male and brownish in the female; base of the tentacles
purplish or yellowish ; size 4 mm. by 3 mm. : Florida to
Vineyard Sound; Europe.

S. rugosa Mayer. Similar to preceding, but with 14
rudimentary marginal tentacles together with the 2 long
ones; base of the tentacles and manubrium brick red;
5 mm. high: common at Newport, R. I., and southwards.

4. RATHKEA Brandt (Lizzia
Forbes). Trophosome unknown.
Gonosome: medusa subconical with
marginal tentacles in 8 clusters of 3
to 5 each; young with only 4 ten-
tacles; manubrium buds off young
medusae; 4 branching oral tentacles;
no ocelli: 8 species.

R. grata A. Agassiz (Fig. 159).

Medusa 3 to 6 mm. high, transparent: Massachusetts
Bay to Newport, R. I.; often common.

5. NEMOPSIS Agassiz. Trophosome like Bou-
gainvillia except that the medusae arise from the
hydranths. Gonosome: medusa like Bougainvillia
but with a pair of short-knobbed tentacles directed
upwards from each group of long tentacles and with
gonads extending on to the subumbrella: 2 species.

N. bachei Ag. (Fig. 160). Medusa 6 to 10 mm.
high: Florida to Vineyard Sound; common.

Fig. 159— Rathkea grata (Hargitt).

Fig. 160

Nemopsis bachei
(Mayer).

• . FAMILY 4. EUDENRIIDAE.

Trophosome: colony branching, rising from a reticulated hydro-
rhiza ; perisarc distinct and variously annulated ; hydranth with trumpet-
shaped hypostome (Fig. 150) and a single whorl of filiform tentacles.
Gonosome: no free medusae; male sporosacs in a whorl just beneath,
and the female sporosacs usually just above the tentacles and occasion-
ally on the hydrocaulus: 1 genus.

ETTDENDRITJM Ehrenberg. With the characters of the family : about
8 American species.

TUBULARIAE

99

Key to the species of Eudenriidae here described :

<*! Colony large (8 to 15 cm. high).

6X Branches annulated at their base only E. BAMOSUM

&2 Branches completely annulated B. DISPAB

o2 Colony small ( less than 3 cm. long) E. TENUB

E. ramosum (L.) (Figs. 150 and 161). Colony profusely branched,
.10 to 15 cm. high, with symmetrical branches; tentacles about 20; male
sporosacs reddish and in moniliform clusters; female sporosacs orange
and pyriform: abundant on piles, rocks, etc., in shallow water from
North Carolina to Labrador; Pacific Coast; Europe.

E. dispar Agassiz. Colony less profusely branched than above,

Fig. 161 Fig. 162

Fig. 161 — Eudendrium ramosum (from Hargitt). Fig. 162 — Hydractinia echinata

(McMurrichJ. 1, feeding hydranth ; 2, defensive

hydranth ; 3, reproductive hydranth.

6 to 10 cm. high; tentacles about 28; sexes distinct: in deeper water
from Vineyard Sound to Bay of Fundy.

E. tenue A. Agassiz. Colony irregularly branched, 25 mm. in height ;
male sporosacs moniliform and pink; female sporosacs orange and scat-
tered over the hydrocaulus: on seaweed, etc., in shallow water from
Buzzard's Bay to Bay of Fundy; not abundant.

FAMILY 5. HYDBACTINIIDAE.

Trophosome: colony incrusting, the polyps rising separately from
an incrusted, spiny hydrorhiza to which the perisarc is confined, and
polymorphic, consisting of 3 types of individuals: (1) feeding hydranths,
which have a single whorl of tentacles; (2) reproductive individuals,
bearing clusters of sporosacs; and (3) defensive individuals usually
without tentacles but with numerous nematocysts at the apex. Gono-
some: sporosacs and no free medusae present: 1 genus.

100 CCELENTEEATA

HYDRACTINIA Van Beneden. With the characters of the family:
2 American species.

H. echinata Fleming (Fig. 162). Colony 10 mm. high; reproductive
individuals without tentacles: usually on the shells of hermit crabs but
also on stones, fucus, piles, etc.; very common on Atlantic coast; Europe.

H. milleri Torrey. Colony 5 mm. high; reproductive individuals
with tentacles: California.

FAMILY 6. PODOCOBYNIDAE.

Trophosome: like that of Hydractiniidae. Gonosome: free medusae
present, each with 4 radial canals and 4 or 8 or more marginal tentacles :
several genera.

Key to the genera of Podocorynidae here described :
Oj Medusa with long tentacles, hydroid on Limulus, shells of hermit crabs,

etc 1. PODOCORYNE

aa Marginal tentacles of medusa rudimentary ; hydroid on Nassa. . .2. STYLACTIS

1. PODOCORYNE Sars. Trophosome: like Hydractinia. Gonosome:
medusa globular with 8 or more rather thick tentacles : 11 species.

P. carnea Sars (Fig. 163). Medusa very transparent, 3 mm. high,
with 4 marginal tentacles in the young and 24 to 32 in the adult;

manubrium reddish with 4 oral tentacles:
hydroid on Limulus, crabs, rocks, etc.

P. fulgurans (A. Agassiz). Medusa 1
mm. high, hemispherical, with 8 marginal and
4 oral tentacles; manubrium buds off young
medusae: North Carolina to Massachusetts
Bay ; common ; often brightly phosphorescent.
2. STYLACTIS Allman. Trophosome: col-
ony consisting of very long, slender hydranths
rising from a reticular base. Gonosome : a

sporosac in the European species, but in the
Fig. 163 — Podocoryne car- A -^i T

nea (Mayer). American a medusa with rudimentary ten-

tacles: several species, 2 American.

S. hooperi Sigerfoos. Hydranths 20 mm. long with 18 to 25 ten-
tacles; medusa globular, 1 mm. in height with 8 rudimentary, marginal
and no oral tentacles and borne on specialized hydranths, just below the
tentacles; no ocelli: Long Island and Vineyard Sounds, on Nassa
obsoleta.

FAMILY 7. PENNARIIDAE.

Trophosome: colony regularly branching; hydranth with a basal
whorl of 10 to 12 filiform tentacles and also a number of short knobbed

TUBULABIAE

101

tentacles on the hypostome. Gonosome: either a free or a sessile
medusa with 4 radiating canals and 4 rudimentary tentacles: about 7
genera.

PENNARIA Oken. With the characters of the family: about 6
species.

P. tiarella (Ayres) (Fig. 164). The bright pink hydroid colony
may be 15 cm. in height, and is attached to piles, rocks, or seaweed in
shallow water; medusoid buds on the side of the hydranth; medusa

Fig. 164

Fig. 165

Fig. 164 — Pennaria tiarella; a hydranth with a medusoid bud (Hargitt). Fig. 165 —
Pennaria tiarella; a male (A) and a female (B) medusa (Hargitt).

(Fig. 165) an elongated bell about 2 mm. long with 4 rudimentary ten-
tacles; the medusa is free-swimming chiefly during midsummer, the
greater part of the year it is more or less sessile : common from Maine
to Florida.

FAMILY 8. CORYMORPHIDAE.

Trophosome: hydranths solitary and
of large size with a basal and several
distal whorls of filiform tentacles; me-
dusae produced just within the basal
tentacles. Gonosome: free medusae with
4 radial canals and 1 to 4 marginal ten-
tacles, one of which is longer than the
rest: several genera.

1. CORYMORPHA Sars. Large soli-
tary polyps with a soft striated outer
surface and no well-defined perisarc,
rooted by filamentous processes : 5 species.

C. pendula Agassiz (Fig. 166).
Polyp pendant, 3 to 10 cm. high and
bright pink; medusa bell-shaped with a projection at the apex, with
1 large and 1 to 3 rudimentary marginal tentacles; manubrium extends

Fig. 166 — CorymorpJia pendula
(Agassiz).

102

CCELENTERATA

to the velum ; length 6 mm. : common from Vineyard Sound to Gulf of
St. Lawrence in 8 to 30 fathoms.

2. HYBOCODON Agassiz. Trophosome: polyp large, solitary, with a
well-defined perisarc and hydrorhiza; hydranth with a basal and 2 distal
whorls of filiform tentacles; just within the base of the former medusae
are budded off: 2 species.

H. prolifer Agassiz (Fig. 167). Orange-colored hydroids 4 cm. high,
with longitudinally striated perisarc which is annulated just below the
hydranth; medusa hemispherical and asymmetrical, with 5 medidional
orange-colored bands at maturity and with 1 to 3 long marginal ten-
tacles, from the thick base of which secondary medusae bud : on rocks in
clear water from Vineyard Sound to Massachusetts Bay; not common.

3. EcTOPLEUBA Agassiz. Trophosome : hydroid like Tubularia, being
indistinguishable when without gonophores. Gonosome: free medusae,

Fig. 167 Fig. 168 Fig. 169

Fig. 167— Hybocodon prolifer (Mayer). Fig. 168 — Ectopleura ochracea (Hargitt).
Fig. 169 — Turritopsis nutricula (Mayer).

rather elongate, with 2 or 4 tentacles from the base of which lines of
nematocysts extend on the surface of the bell to its apex : 3 species.

E. ochracea A. Agassiz (Fig. 168). Medusa about 3 mm. in height
with a large manubrium and 8 longitudinal bands of nematocysts on
exurabrella: Cape Cod to South Carolina; common.

FAMILY 9. DENDBOCLAVIDAE.

Trophosome: colony branching, with an elongate hydranth at the
end of each branch bearing 18 to 20 short filiform tentacles scat-
tered over it. Gonosome: a free-swimming medusa produced below
the hydranth: 2 genera.

1. TURRITOPSIS McCrady. Hydroid form as above; medusa hemi-
spherical, with 8 to 70 equidistant tentacles; 4 reddish gonads: 1 species.

T. nutricula McCrady (Fig. 169). Medusa 4 to 5 mm. in diameter:
Cape Cod to Florida; often common.

TUBULARIAE

103

FAMILY 10. TUBULARIIDAE.

Trophosome: polyps solitary or colonial, of large size and bright
pink in color; hydranths with a basal and a distal whorl of filiform ten-
tacles. Gonosome: medusoids remain attached to the polyp, being sus-
pended from long-branched stalks above the basal tentacles and varying
in form from sporosacs to perfect medusae ; no free medusae ; the female
medusoids produce peculiar free-swimming hydroid-like bodies called
actinules: 1 genus.

TUBTTLARIA L. With the characters of the family : about 20 species.

Key to the species of Tubularia here described :

al Polyps unbranched, in groups of 4 to 8 ; medusoids with distinct radial

canals T. COUTHOUYI

a2 Polyps branched ; often no distinct radial canals in medusoids.

&! Hydranth with collar T. LARYNX

62 No collar present.
Cj Hydranth large ; often in muddy water.

dt Sporosac with conical apical process T. SPECTABILTS

dy Female sporosac with flattened apical process T. CROCEA

cz Hydranth small ; often in clear water T. TENELLA

T. couthouyi Agassiz (Fig. 170).
Individuals unbranched, 7 to 15 cm.
high; hydranth often expanding 20
mm. or more, with a basal whorl of 30
to 40 tentacles ; medusoid with distinct
radial canals: on sandy bottoms in
shallow or brackish water, in clusters
of 5 to 10 individuals; New England
coast.

T. larynx Ellis and Solander. In-
dividuals somewhat branched and ex-
tensively annulated and living in clus-
ters, 2 to 5 cm. high; a collar-like
expansion just below hydranth, the
latter with 16 to 20 basal tentacles;
female medusoid with a conical apical process and no distinct radial
canals : in shallow water from Cape Cod northwards ; California ; Europe ;
on rocky and shelly bottoms.

T. spectabilis (Ag.). Colony irregularly branched, sparsely annu-
lated, and 8 to 10 cm. high, growing in a tangled mass; 20 basal ten-
tacles: in shallow water from Rhode Island to Bay of Fundy.

T. tenella (Ag.). Colony 25 to 40 mm. high and like preceding
form but more loosely branched: in tide pools and the open ocean;
Massachusetts Bay to Bay of Fundy.

Fig. 170 — Tubularia couthouyi
(Agassiz).

104

CCELENTEEATA

Fig. 171 — 'Tubularla crocea (Agassiz).
B, a single hydranth.

B

A, a colony

T. (Parypha Ag.)
crocea (Ag.) (Fig. 171).
Colonies growing in dense
tufts of long tangled
stems of from 8 to 10 cm.
in height ; sparingly
branched ; basal tentacles
20 to 24; apical process of
the female sporosac flat-
tened: common on piles,
docks, etc., in shallow
water from Boston south-
wards; California,

ORDER 4. CAMPANULARIAE.* (CALYPTOBLASTEA; LEPTOMEDUSAE. )

Colonial hydromedusans with two kinds of polyps (Fig. 172), the
hydranths or the nutritutive polyps and the blastostyles or the reproduc-
tive polyps. The perisarc does not end at the base of the polyp, as in
the tubularians, but continues over it, forming, in the case of the

hydranth a protective cup called the hydro-

theca and in the case of the blastostyle a

cylindrical capsule called a gonangium or a

gonotheca. In some species the open end of

the hydrotheca may be closed by projections

or valves which form an operculum (Fig.

173); in some species also the blastostyle

projects out of the mouth of the gonangium

and forms a large cap-

sule or brood chamber

in which the eggs de-

velop, called the aero-

cyst (Fig. 178). The

hydranth has never

more than a single

whorl of tentacles and

can in most cases be

retracted within its

hydrotheca or extended
beyond it. The blastostyle cannot usually be extended beyond its
gonangium and produces within it the gonophores; these constitute

Fig. 172 — A campanularian
hydroid (from Hegner). 1,
hydranth ; 2, hydrotheca ; 3,
blastostyle ; 4, gonangium.

Campanularian oper-
cula (Nutting). A,

two-valved operculum ;

B, one-valved opercu-
lum.

* See "The Leptomedusae of the San Diego Region," by H. B. Torrey, Uni. of
Cal. Pub., Vol. 6, p. 11.

CAMPANULARIAE 105

the medusoid generation and may either be liberated as free medusae,
or, remaining in the gonangium, produce the sexual products there,
which escape from the gonangium as free larvae. The medusae
(Fig. 191) are known as Leptomedusae and (except in the Thauman-
tiidae) have lithocysts and not ocelli as sense organs: they bear the
gonads beneath the radial canals on the subumbrella: about 8 families.
Key to the families of Campanulariae here described :

A. THE HYDROIDS.

Oj Hydrotheca sessile, i. e., not joined to the stem by a stalk ; gonangium contains

sporosacs.
6j Hydrothecae in 2 rows (except Hydrallmania) either opposite to each other

on the stem or not 1. SEBTULARIIDAE

62 Hydrothecae in a single row on the stem 2. PLUMULABIIDAE

a2 Hydrotheca stalked and bell-shaped.

&! The gonophores are sporosacs 3. CAMPANULARIIDAE

&2 The gonophores are medusae ; hydroid forms very little known except in the
genera O&eZia, Clytia, and Laodicea.

4. EUCOPIDAE. 5. ^EQUOREIDAE. 6. THAUMANTIIDAE

B. THE MEDUSAE.

The 1st, 2nd, and 3d families produce only sporosacs and no free medusae.

di Four simple radial canals; lithocysts and no ocelli present 4. EUCOPIDAE

a2 Radial canals numerous (8-100) 5. ^QUOBEIDAE

aa Radial canals 4 or 8 ; ocelli present and no lithocysts .. 6. THAUMANTIIDAE

FAMILY 1. SERTULARIIDAE.*

Trophosome: colony usually branching; hydrothecae sessile (not
stalked), almost all with opercula (Fig. 173) and forming two rows
along opposite sides of the hydrocaulus (except Hydrallmania). Gono-
some: gonangia much larger than the hydrothecae, there being only a
few in the colony, and occurring only at certain times of the year; each
gonangium contains a blastostyle which produces planulae; no free
medusae: about 15 genera and 135 American species.

Key to the genera of Sertulariidae here described :

Oj Hydrothecae in two rows.
&! Hydrothecae exactly opposite each other.

G! Operculum in 2 pieces (Fig. 173, A) 1. SERTULABIA

c2 Operculum in 1 piece (Fig. 173, B) 3. DIPHASIA

&2 Hydrothecae alternate or subalternate to each other.
Ci Hydrothecae stand out from the stem.
d: Hydrotheca with toothed margin ; operculum of 3 or 4 pieces.

2. SERTULARELLA
d2 Hydrotheca with smooth margin ; operculum of one piece. .4. ABIETINARIA

c2 Hydrothecae closely pressed against the stem 5. THUIARIA

a2 Hydrothecae in one row, the openings turning alternately to the right and
left 6. HYDRALLMANIA

* See "American Hydroids, Part II, The Sertularldae," by C. C. Nutting, U. S.
Nat. Mus. Spec. Bull., No. 4, 1904.

106

CCELENTERATA

Fig. 174— Sertularia pumila
(Nutting). A, portion of
a colony ; B, a gonangium.

1. SERTULARIA L. Hydrotbecae in pairs along the stem, the mem-
bers of a pair being exactly opposite each other; operculum paired
(Fig. 173, A) ; gonangia have plain margins and are of simple form: about
20 American species.

S. pumila L. (Fig. 174). A simple or more or less branched colony
1 to 5 cm. high attached by a creeping hydrorhiza, the stem being divided

into short internodes, each bearing a pair
of hydrothecae; gonangia oval, sessile and
often bearing acrocysts, the male gonan-
gium being somewhat more slender than the
female : common on fucus, etc., between tide
lines, from New Jersey to the Arctic Ocean ;
California; Europe.

2. SERTTILARELLA Gray. Similar to
preceding genus, but differs from it in that
the hydrothecae are alternate on the hy-
drocaulus and not opposite, and possess a

prominent operculum composed of several pieces; gonangium usually
deeply annulated: about 50 American species.

Key to the species of Sertularia here described :
»! Margin of hydrotheca with 4 slight teeth.
6j Hydrotheca annulated.

GI Annulations only on upper side S. GAYI

c2 Annulation complete S. RUGOSA

62 Hydrotheca smooth S. POLYZONIAS

a2 Margin of hydrotheca with 3 teeth S. TBICUSPIDATA

S. rugosa (L.) (Fig. 175). A small colony 2 cm. high, either un-
branched or little branched and with annulated stem; hydrothecae
crowded, annulated and with 4 marginal teeth ; gonangia
large, annulated and with four-toothed aperture: New
England coast; Puget Sound; Europe.

S. gayi (Lamouroux). Colony attaining a height of
15 cm. and with paired or alternate branches ; hydrothe-
cae wrinkled or partially annulated and with a four-
toothed aperture; gonangia elongate, ovate, tapering
towards both ends, annulated in upper portion : Atlantic
coast; Europe.

S. polyzonias (L.). Irregularly branching colony
attaining a height of 12 cm. ; hydrotheca smooth, with 4
teeth; gonangium deeply annulated and with 4 teeth
Pacific coast; cosmopolitan; common.

S. tricuspidata (Alder). Colony 12 cm. high or less and slender
with alternate branches; hydrotheca smooth, with 3 teeth; gonangium

Fig. 175

Sertularella

rugosa
(Kingsley).

Atlantic and

CAMPANULARIAE

107

Fig. 176— Diphaaia fal-
low (Hargitt).

with deep annulations and a bowl-shaped orifice: New England coast;
common; north Pacific coast; Europe.

3. DIPHASIA Agassiz. Colony more or less branching, jointed, the
bydrothecae in pairs opposite each other and standing out from the
stem; a single operculum present (Fig. 173, B);
gonangia dimorphic, the female being the larger
and often annulated, and with a brood pouch in
its distal half, the male with a central tubular
orifice and 4 spines: 10 American species.

D. fallax (Johnston) (Fig. 176). Colony
about 8 cm. high, with simple branching, the
ends of the branches being often tendril-like;
gonangia elongate ; female gonangia oval, deeply
cleft into 4 segments: Massachusetts Bay to
Bay of Fundy; Europe.

D. rosacea (L.). Colony delicate, about 8
cm. high, branching alternately ; gonangium with
longitudinal ridges terminating, in the male, in
the teeth which surround the orifice: northerly
New England coast; Europe; common.

4. ABIETINAEIA Kirchenpauer. Hydrothecae flask-
shaped and alternate or subalternate with operculum of
one piece on the side next to the stem and with smooth
margin: 16 species.

A. abietina (L.) Sea-fir (Fig. 177). Colony large and
bushy, being sometimes 30 cm. high or more, with alter-
nate branching, with very large hydrothecae and relatively
small gonangia : from Vineyard Sound to Labrador; north
Pacific; Europe.

5. THTTIARIA Fleming. Hydrothecae alternat-
ing with each other, more than a pair to an inter-
node and closely applied to the stem, which is
jointed: 20 species.

T. thuja (L.). Colony very rigid, sometimes
25 em. in height, zigzag in shape and annulated
near the base; perisarc very dark in color; gonan-
gia smooth and pyriform: in shallow water on
northerly New England coast; Pacific coast;
Europe.

T. argentea (L.) (Fig. 178). A large bushy colony, often 20 or 30
em. high, branching alternately or dichotomously ; gonangia broad, taper-
ing towards the base, with a circular aperture and usually 2 spines : very

Fig. 177

AMetinaria

abietina

(Kingsley).

Fig. 178 — TJiuiaria ar-
gentea (Kingsley). g,
gonangium ; a, aero-
cyst.

108

CCELENTERATA

common; New Jersey to the Arctic Ocean from low-water mark to 100
fathoms, usually in rather deep water; Pacific coast; Europe.

T. cupressina (L.). A slender, elongated
colony, often 20 cm. high, branching alter-
nately and dichotomously ; gonangia elongate
with a prominent spine at each side of the
aperture: same habitat as the preceding but
less abundant.

6. HYDRALLMANIA Hincks. Hydrothecae
in a single row - projecting out from the
hydrocaulus alternately to the right and the
left; colony pinnately branching: 3 species.
H. falcata (L.) (Fig. 179). Colony often
30 cm. high, slender, rather rigid and with
simple branching; on each branch the second-
ary branches are very regular and feather-like;
gonangia ovate and simple: on stones, shells,
fJ5&a (2^T"AT5S etc., on New England coast and in Long Island
Sth!.' branCh Wlth hy~ Sound; Puget Sound; Europe.

FAMILY 2. PLUMULARIIDAE.*

Trophosome: usually a branched colony with sessile hydranths,
which are borne in a row on small branches called hydrocladia (Fig. 180) ;
between the hydranths and on the main stem and branches are nemato-
phores, small specialized defensive polyps, each of which consists of a
hydrotheca and an elongated body armed with nematocysts. Gonosome :
gonangia large, the blastostyles producing planulae and never medusae :
about 43 genera and over 300 species, being a quarter of all known
hydroids; about 100 species occur along the Atlantic coast and in the
West Indies.

Key to the genera of Plumulariidae here described:

01 Gonangia not protected by special branchlets ; nematophores trumpet-shaped

and movable.

&i Hydrocladia do not branch.
G! Colony not dichotomously branched ; the hydrocladia arranged in whorls

or scattered along the stem 1. ANTENNULABIA

c. Branching dichotomous ; hydrocladia all arise from the upper side of

branches 2. MONOST^ECHAS

Z>2 Hydrocladia forked 3. SCHIZOTRICHA

02 Gonangia protected by special branchlets ; nematophores immovable.

4. CLADOCARPUS

* See "American Hydroids, Part I, The Plumularidae," by C. C. Nutting, U. S.
Nat. Mus. Spec. Bull. No. 4, 1900.

CAMPANULAEIAE

109

1. ANTENNULASIA Lamarck. Main stem of colony simple or
sparsely branched and attached by a massive hydrorhiza; hydrotheca cup-
shaped; gonangia borne in the axils of the branches: 6 American
species.

A. antennina (L.) (Fig. 180). Colony a dense cluster of upright
stems, often 20 cm. high, obscurely jointed, each internode bearing a
whorl of fine branches (hy-
drocladia) on which are the
hydranths and the nemato-
phores; gonangia ovate and
of large size, in the axils of
the hydrocladia: from Mar-
tha's Vineyard to Bay of
Fundy in 6 to 60 fathoms;
Europe.

2. MoNOST-ECHAS All-
man. Colony branching

dichotomously and attaining a height of 15 cm.; hydrocladia spring-
ing all from the upper side of the main branches: 1 American
species.

M. quadridens (McCrady). From Martha's Vineyard southwards.

3. SCHIZOTRICHA Allman. Colony usually a cluster of simple stems;
hydrocladia arranged pinnately and branched in mature specimens:
4 American species.

S. tenella (Verrill). Colony branching dichotomously and attain-
ing a height of 5 cm.; stem divided alternately into longer and shorter

Fig. 180 — Antennularia antennina (Nutting),
hydranth ; 2, nematophore ; 3, gonangium ;
4, hydrocladium.

Fig. 181

Fig. 182

Fig. 183

Fig. 181 — Schizotricha gracillima (Nutting). Fig. 182 — Cladocarpus flexilis (Nut-
ting). Fig. 183 — Halecium halecinum (Hargitt).

internodes, the latter bearing each a hydrocladium; gonangium cornu-
copia-shaped : Long Island and Vineyard Sounds, in shallow water, often
on piles.

110 CCELENTEBATA

S. gracillima (G. 0. Sars) (Fig. 181). Colony about 5 cm. high;
branches divided into regular internodes, each bearing a hydrocladium :
New England coast; Europe.

4. CLADOCARPITS Allman. Colony usually branched; hydrocladia
not branched ; gonangia borne on the stem at the base of the hydrocladia
and protected by special branchlets armed with nematophores : 15
American species.

C. flexilis Verrill (Fig. 182). Colony up to 20 cm. long and slender;
hydrotheca long and cylindrical, lying close to the hydrocladium; pro-
tecting branchlets of the gonangia branched like deer's horns: in moder-
ately deep water along the Atlantic coast; common.

FAMILY 3. CAMPANULABIIDAE.

Trophosome: either a branched or simple colony on which are bell-
shaped and usually stalked hydrothecae; hypostome trumpet-shaped.
Gonosome: gonangium large, the blastostyle producing planulae and
never free medusae: about 33 genera.

Key to the genera of Campanulariidae here described:

«! Hydrotheca rudimentary, the hydranth not being entirely retracted

into it 1. HALECIUM

o,Hydrotheca not rudimentary.

6a Blastostyle does not project from the gonangium.
<?! Stem not completely annulated.

cfi Gonangium without acrocyst, colony not parasitic 2. CAMPANULABIA

<13 Gonangium with acrocyst ; colony parasitic on other hydroids, etc.

3. CALYCELLA

c2 Stem completely annulated 4. OPERCULABELLA

ft, Blastostyle projects from the gonangium 5. GONOTHYREA

1. HALECIUM Oken. Branching colonies with creeping hydrorhiza;
the hydrothecae are more or less rudimentary, being shallow and
disc-like or funnel-shaped, the margin often with a circle of dots,
into which the hydranths can be only partially retracted: numerous
species.

H. halecinum (L.) (Fig. 183). Colony 10 to 20 cm. high, rigid;
hydrothecae alternate on the stem, cylindrical, often annulated; gonan-
gia appear in a row, the male gonangium slender and club-shaped, the
female rather irregular in shape with broad distal end and a terminal
aperture: New Jersey to Labrador; in shallow water; Puget Sound to
Alaska; Europe.

2. CAMPANULARIA Lamouroux. Colony either branched or simple,
with bell-shaped hydrothecae, which are without operculum, and with
or without marginal teeth: many species.

CAMPANULARIAE

111

Key to the species of Campanularia here described:

«! Colony not branched, the hydranths rising separately from hydrorhiza.

&! Margin of aperture of hydrotheca not toothed C. POTEBIUM

&2 Margin toothed.

cx Teeth square at top C. HINCKSI

c2 Teeth very shallow, the margin being sinuous C. VOLUBILIS

c2 Colony branched.

6j Colony large, over 10 cm. high.

d Margin of aperture toothed C. VERTICILLATA

c2 Margin of aperture not toothed C. AMPHORA

62 Colony small, under 3 cm. high C. FLEXUOSA

C. poterium (Agassiz). Colony unbranched, with the hydranths at
the end of long, completely annulated stalks, which rise separately from
the hydrorhiza; aperture of hydrotheca not toothed;
hydranth with 24 tentacles; gonangia slender and ovate,
rising from the hydrorhiza: Vineyard Sound to Labrador;
low-water mark to 30 fathoms, common on seaweed;
Europe.

C. hincksi Alder (Fig. 184). Colony unbranched, the
hydranths . at the end of long and partially annulated
stalks which rise separately from the hydrorhiza; aper-
ture of hydrotheca with 12 square-topped teeth; gonangia
on short stalks and annulated: from Vineyard Sound to
Maine, on stones and shells; southern California; Europe.
C. volubilis (L.). Colony unbranched, the hydranths
at the end of long completely annulated stalks which rise separately
from the hydrorhiza ; aperture of hydrotheca with
10 shallow-rounded teeth; gonangia rise from the
hydrorhiza: from Vineyard Sound to Greenland;
low-water mark to 100 fathoms; common; Pacific
coast; Europe.

C. verticillata (L.). Colony branched, attain-
ing a height of 12 cm. ; hydrothecae with a toothed
aperture borne on long, partially annulated stalks
which form whorls around the stem: Long Island
Sound to Maine, in 4 to 45 fathoms; Alaska;
Europe.

C. amphora (Agassiz). Colony branched,
attaining a height of 15 cm.; hydrothecae with
untoothed aperture and with a swollen stalk;
hydranth with 30 tentacles ; gonangia truncate : from Long Island Sound
to Gulf of St. Lawrence; common.

C. flexuosa (Hincks) (Fig. 185). Colony 25 mm. high, branched
irregularly; stem annulated near the base of the branches; hydrothecae

Fig. 184

Campanu-
laria hincksi
(Kingsley).

Fig. 185 — Campanularia.
flexuosa (Hargitt).

112

CCELENTERATA

with untoothed aperture and with annulated stalks; gonangia large:
Long Island Sound to Labrador, on piles, etc., abundant towards the
north; Europe.

3. CALYCELLA Hincks. Hydrorhiza parasitic on other hydroids,
Bryozoa, etc., and sending forth short annulated stalks bearing elongate
cylindrical hydrothecae which have opercula; gonangium oval, rising
from the hydrorhiza and bearing a globular acrocyst.

C. syringa (L.). Hydrotheca longer than
its stalk: Long Island sound to Maine; com-
mon; Pacific coast; Europe.

4. OPERCULARELLA Hincks. Stem annu-
lated throughout and sparsely branched or
unbranched; hydrotheca with operculum;
gonangium with acrocyst.

0. lacerata Hincks. Hydrothecae with
short stalks; segments of operculum very long
and slender: Long Island Sound to Maine, on
docks, etc.

5. GONOTHYREA Allman. Stem erect, ir-
regularly branched, more or less annulated;
hydrotheca bell-shaped, with toothed margin;
the blastostyle produces fixed, medusiform
sporosacs with radial canals and tentacles, which
project out of the gonangia but are not free-
swimming: several species.

G. loveni Allman (Fig. 186). Stem 10 to
15 mm. high; from the mature gonangium project 3 to 5 sporosacs: on
shells, stones, etc., in shallow water from Long Island Sound to Maine;
Europe.

G. clarki Torrey. Similar to the above but without radial canals in
the sporosacs; hydrotheca deep, with margin having 10 square-topped or
bicuspid teeth: Pacific Coast from California to Alaska; often common
in shallow water.

FAMILY 4. EUCOPIDAE.

Trophosome: colonial, either branched or simple; hydrotheca bell-
shaped and stalked, the margin of the aperture either toothed or not;
gonangia large and usually in the axils of the branches. Gonosome:
gonangium large, the blastostyle producing free medusae with lithocysts
and usually without ocelli, with 4 radial canals, beneath which on the
subumbrella are the gonads, there being as many gonads as radial
canals: about 34 genera.

Fig. 186 — Gonothyrea
loveni (Hargitt).

CAMPANULARIAE

113

Key to the genera of Eucopidae here described (hydroid form well
known in Obelia and Clytia alone) :

G! Manubrium of medusa short ; hydroid mostly a branching colony.
^Medusa flat and disc-like ; hydroid a branching colony ; hydrotheca often

without a toothed margin 1. OBELIA

&2 Medusa bell-shaped or hemispherical.
G! Medusa with no more than 16 marginal tentacles.
di Medusa without cirri at the base of the tentacles; hydroid not or very

sparsely branched ; hydrotheca with toothed margin 2. CLYTIA

<£, Medusa with 4 or more tentacles, each of which has 2 basal cirri.

4. EUCHEILOTA

c2 Medusa with more than 16 tentacles.

diOral lobes frilled 3. TIABOPSIS

d2 Oral lobes not frilled 5. OCEANIA

03 Manubrium of medusa very long; hydroid mostly unknown.

6i Tentacles 4 6. EUTIMA

e2 Tentacles of adult numerous 7. TIMA

1. OBELIA Peron and Lesueur. Hydroid colony usually branched,
the stem with annulations at the base of the branches and the hydranths ;
hydrotheca often with * untoothed margin; gonangium

with a small terminal ^K" /* aperture, usually surrounded by
a collar or neck; me- %(PJ^ dusa more or less disc-shaped, 1

to 6 mm. in diameter, j( \i with 12 or more marginal

tentacles and 8 (P|\ | J^|?k lithocysts, often swim-

ming with everted ^o^W/ Jp^=»«^ bell: numerous species,

Fig. 187 — Obelia dichotoma (Mayer). A, entire colony; B, colony enlarged; C,

medusa.

the medusae of which can often not be distinguished from one
another.

0. commissuralis McCrady. Colony tree-like with long central trunk,

15 to 20 cm. high, sparsely branched, the side branches springing out at
right angles; hydrotheca not toothed; gonangia elongate; medusa with

16 or more tentacles: on docks, algae, etc., from South Carolina to Bay
of Fundy; common; California.

0. dichotoma (L.) (Fig. 187). Colony rather small with a deep
brown stem and a general tree-like appearance; branches zigzag; hydro-
theca elongate without toothed margin; gonangia long and conical;

114

CCELENTERATA

Fig. 188

geniculata
(Hargitt).

Fig. 189—Clytia Uco-
phora (Mayer).

medusa with 16 tentacles at liberation : from South Carolina northwards ;
common on stones, seaweed, etc.; Pacific coast; Europe.

0. geniculata (L.) (Fig. 188). Colony not more than 30 mm. high
and consisting usually of a single zigzag stem bearing
alternate hydranths on short annulated stalks ; gonan-
gia borne in the angles of these stalks; medusa with
24 tentacles at liberation: on docks, fucus, etc., from
Long Island to Labrador;
very common; California;
cosmopolitan.

0. gelatinosa (Pallas).
Colony tree-like, profusely
branching and very large,
being sometimes 25 cm. high
or more, with central stems
and zigzag branches; hydro-
thecae small, with toothed margin; gonangia small; medusa with 16
tentacles at time of liberation: on docks, seaweed, etc., in shallow water
from New Jersey to Massachusetts Bay; very common; Puget Sound;
Europe.

2. CLYTIA Lamouroux. Hydroid colony sparsely branched or not
at all, the hydranths being at the end of a usually long, more or less
annulated stalk which rises from the hydrorhiza; hydrotheca with
toothed margin; gonangia often annulated, on the hydrorhiza or the
stem; medusa with 16 tentacles and 16 lithocysts: 8 species.

C. bicophora Agassiz (Fig. 189). Colony about 10 mm. high; medusa
5 mm. in diameter, hemispherical when liberated but later becoming

more flattened; gonads brown, manubrium
short, with 4 small oral lobes: from South
Carolina to Arctic Ocean, on fucus, docks,
etc., in shallow water; often common.

3. TIAEOPSIS Agassiz. Hydroid form un-
known; medusa hemispherical; marginal ten-
tacles very numerous in adult; manubrium
short with frilled mouth opening; 8 lithocysts
above each of which is an ocellus: 6 species.
T. diademata Agassiz (Fig. 190). Medusa
15 mm. in diameter, with sloping sides; manubrium with 4 prominent
lips: New England coast; often abundant.

4. ETTCHEILOTA McCrady. Hydroid form unknown; medusa hemi-
spherical; tentacles each with a pair of lateral cirri at its base: 6
species.

Fig. 190 — Tiaropsis diade-
mata (Mayer).

CAMPANULARIAE

115

E. duodecimalis A. Agassiz (Fig. 191). Tentacles 4, each with a pair
of cirri at its base; diameter 2.5 mm.; manubrium very short: Cape Cod
to Florida; often common.

5. OCEANIA Peron and Lesueur. Hydroid form mostly unknown;
medusa hemispherical with 16 or more tentacles; lithocysts also numer-
ous in adults, 2 being between each two marginal tentacles; gonads

Fig. 191

Fig. 192

Fig. 193

Fig. 191—Eucheilota duodecimalis (Mayer). Fig. 192 — Oceania languida (Hargitt).
Fig. 193 — Eutima mira (Hargitt).

colored and borne along the outer half of radial canals: manubrium
with 4 everted oral lobes: 6 species.

0. languida A. Agassiz (Fig. 192). Gonads brownish or pink or
green; tentacles 20 or more; diameter 20 mm.: from Bay of Fundy to
Florida; often common.

6. EUTIMA McCrady. Hydroid form unknown in most species;
medusa bell-shaped with 4 or more tentacles and a very long manubrium
extending far out of the bell ; 8 lithocysts : 12 species.

E. mira McCr. (Fig. 193). Medusa 2 cm.
in diameter and half as high, with gonads ex-
tending along almost the entire length of radial
canals; tentacles 4 in number and very long,
the base swollen and colored green: Florida to
New England; very common at Woods Hole in
August.

7. TIMA Eschscholtz. Hydroid form minute;
medusa hemispherical with a long manubrium
sometimes extending out of the bell, at the end
of which are 4 frilled projections surrounding the

mouth; tentacles numerous; gonads extending the length of the radial
canals and the manubrium: 5 species.

T. formosa Agassiz (Fig. 194). Diameter 4 to 8 cm.; gonads and
oral lobes milk white: New England coast; often common, especially in
the spring.

Fig. 194

Tima formosa (Har-
gitt).

116

CCELENTERATA

FAMILY 5. ^QUOREIDAE.

Trophosome: mostly unknown. Gonosome: medusa often of large
size and more or less disc-shaped, with from 8 to 100 radial canals;
gonads usually ribbon-like; 8 or more lithocysts; 8 or more marginal
tentacles: about 7 genera.

Key to the genera of ^Equoreidae here described :

Oi Manubrium short.

6j Radial canals 8 to 20 1. HALOPSIS

62 Radial canals 16 to 100 2. ^QUOREA

Oa Manubrium large and long 3. ZYGODACTYLA

1. HALOPSIS A. Agassiz. Medusa disc-like in adult and hemispher-
ical in youth; radial canals 12 to 20 in 4 groups; marginal lithocysts,

tentacles and cirri numerous ;
manubrium short with 4 oral
lobes: 1 species.

H. ocellata A. Ag. Di-
ameter 7 cm.: New England
coast; rare.

Fig. 195 — &quorea tennis (Mayer).

2. -ffiQUOREA Peron and
Lesueur. Hydroid form mi-
nute and mostly unknown;

medusa disc-shaped or hemispherical, with a short, wide manubrium
and numerous radial canals, lithocysts, and tentacles: 10 species.

A. (Ehegmatodes A. Agassiz) tennis
A. Ag. (Fig. 195). Radial canals 20 to
40 with an equal number of gonads; ten-
tacles numerous, long 'and slender, with a
spur above the base of each; diameter 3
to 10 cm.: Vineyard and Long Island
Sounds; very irregular in its occurrence.

A. albida (A. Ag.) Radial canals
and tentacles 80 or more in number;
above each tentacle is a spur; diameter 7
cm.: New England coast.

3. ZYGODACTYLA Brandt. Hydroid
form unknown; medusa arched and with
a large sac-like manubrium with exten-
sive frilled oral lobes extending beyond
the velum; subumbrella with rows of warts between the radial canals:
1 species.

Z. groenlandica (Peron and Lesueur) (Fig. 196). The largest Amer-
ican hydromedusan, measuring 12 cm. or more in diameter; radial canals

Fig. 196 — Zygodactyla graenlan-
dica (Mayer).

TRACHOMEDUSAE 117

and tentacles 80 to 100 in number: Greenland to North Carolina, the
southern variety being pink.

FAMILY 6. THAUMANTIIDAE.

Trophosome: unknown in most genera. Gonosome: medusa ocel-
late and without lithocysts, with a short manubrium and usually 4 to S
radial canals: about 14 genera.

1. MELICERTUM Oken. Hydroid form minute; medusa bell-shaped;
8 radial canals and numerous long tentacles with ocelli at their base:
4 species.

M. campanula Agassiz. Color of medusa light ochre, tentacles and
gonads darker; manubrium short with convoluted lobes; height and

diameter 2 cm.: Cape Cod to Greenland,
often abundant; Europe.

2. LAODICEA Lesson (Lafcea Lamou-
roux). Hydroid an unbranched colony with
Fig. 197— Laodicea calcarata a filiform hydrorhiza; hydrothecae tubular;

\ i i (i rj£ 1 1 1 / .

gonangia oblong, often forming encrusting

masses around the stem; medusa hemispherical when young, but flatter
as adult, with 4 radial canals and numerous tentacles, with basal cirri
and ocelli: 6 species.

L. calcarata A. Agassiz (Fig. 197). Hydroid form usually parasitic
on sertularians ; medusa transparent with 2 tentacles at birth, but many
later, which are quite rigid; manubrium short, with fluted sides; diam-
eter 25 mm.: Massachusetts Bay to Florida.

ORDER 5. TRACHOMEDUSAE.

Trophosome: wanting in most forms, so far as known; where pres-
ent, of minute size and allied apparently to the Tubulariae. Gonosome:
free medusae, usually rather large, more or less bell-shaped, with a
velum and 4, 6, or 8 radial canals, along which on the subumbrella are
the gonads ; manubrium usually long, often extending beyond the velum ;
tentacles often very long and sometimes springing from the exumbrella;
lithocysts with concretions of entodermal origin and either freely pro-
jecting or enclosed in pockets; development apparently direct in most
cases, without alternation of generations, the animals being essentially
open-ocean animals, most of which are not bound to the shores by a
hydroid generation, and where the latter is present it is apparently in a
degenerate condition: 5 families and 80 species.

118 CCELENTERATA

Key to the families of Trachomedusae here described :

«i Radial canals 4 or 6.

&! Gonads not plate-like, usually undulating 1. PETASIDAE

5, Gonads plate-like 3. GEBYONIIDAE

03 Radial canals 8 2. AGLAUBIDAE

FAMILY 1. PETASIDAE.

Trophosome: minute and apparently rudimentary, so far as known,
probably wanting in many cases. Gonosome : medusa with 4 or 6 radial
canals; gonads elongate and much folded or sac-like; tentacles either

Fig. 198— Gonionemus murlachi. A, hydroid (Perkins) ; B, medusa (Mayer).

with or without a pad-like cluster of modified nettle cells near the distal
end for purposes of adhesion; manubrium short: about 14 genera.

1. GONIONEMUS.* A. Agassiz. Trophosome: minute, so far as known.
Gonosome : medusa with 4 radial canals, along the entire length of which
the sinuous gonads extend; adhesive pad near the extremity of each
tentacle; numerous Iithoc3rsts present: 7 species; cosmopolitan.

G. murbachi Mayer (Fig. 198). Trophosome: solitary hydra-like
individuals 1 mm. high with 4 tentacles. Gonosome: medusa 20 mm. in
diameter and half as high; marginal tentacles from 16 to 80, long and
stiff and green at the base; gonads brown; manubrium short with 4
frilled oral lobes: Vineyard and Long Island Sounds.

G. vertens A. Ag. Similar to the above, but higher than wide:
Pacific coast from Washington to Alaska.

2. MICROHYDRA f Potts. Trophosome : a minute hydroid without
tentacles and solitary, but multiplying by lateral budding. Gonosome: a

* See "The Development of Gonionema murbachii," by H. F. Perkins, Proc. Acad.
Nat. Sci., 1902, p. 750.

t See "On the Medusa of Microhydra," etc., by Edward Potts, Quart. Jour. Mic.
Sci., Vol. 50, p. 623, 190G. "Microhydra in 1907," Proc. Delaware Co. Inst., Vol. 3, p.
89, 1908.

TRACHOMEDUSAE

119

medusa which buds from the hydroid, bell-shaped, with 4 radial canals
and 8 tentacles: 1 species, in fresh water.

M. ryderi Potts (Fig. 199). Hydroid cylindrical, with a crown of
nematocysts around the mouth, .5 mm.
long, often branched near the base
into two equal individuals; medusa .3
mm. high and .4 mm. wide at birth;
no sense organs or gonads observed :
on stones in rapid streams in Phila-
delphia; Germany.

3. CRASPEDACUSTA Lankester
(Limnocodium Allman). Trophosome:
minute, without tentacles. Gonosome:
disc-like medusa with 4 radial canals;
tentacles numerous, of several dif-
ferent lengths; lithocysts numerous;
manubrium long: 2 species; distribu-
tion world-wide.

C. sowerbi* Lank. (Fig. 200).
Diameter about 12 mm. ; gonads 4,

suspended from the radial canals, greenish in color; oral lobes, large,

^ ^ crenulated, greenish; bell translucent

"^ -"-.„ ; ** with a faint bluish tint ; 4 long, about

*•* > ? 4

28 shorter and 192 shortest tentacles:
in a fresh-water aquarium in Wash-
ington containing tropical water lilies;
also in similar places in London, Mu-
nich, and Lyons; probably introduced
from South America.

Fig. 200 — Craspedacusta sowerbi
(from Mayer).

FAMILY 2. AGLAUKIDAE.

Trophosome: wanting. Gonosome:
medusa with 8 radial canals, free
lithocysts and gonads in berry-like
masses and numerous tentacles: 5
genera.

Key to the genera of Aglaundae here described :
al Gonads 8.

&! Gonads borne on manubrium 1. AGLAUBA

&2 Gonads borne on radial canals 2. AGLANTHA

a2 Gonads 2 3. PEBSA

* See "Occurrence of Fresh-water Medusa, Limnocodium, in the United States,"
by C. W. Hargitt, Biol. Bull., Vol. 14, p. 304, 1908.

120

CCELENTERATA

Fig. 201

Aglantha digitalis
(Hargitt).

1. AGLAURA Peron and Lesueur. Gonads 8, on manubrium; 8 litho-
cysts: 1 species.

A. hemistoma Per. and Les. Medusa cylindrical or octagonal, 4 nim.
high, truncated above, transparent; radial canals
8; tentacles numerous, very short; 18 finger-like
gonads suspended from the manubrium: cosmo-
politan.

2. AGLANTHA Haeckel. Gonads 8, on subum-
brella: 3 species.

A. digitalis (0. F. Muller) (Fig. 201). Me-
dusa elongate, miter-shaped, 30 mm. high and 15
mm. wide, with 8 radial canals, pinkish and trans-
parent; tentacles numerous; gonads elongate and
suspended from the upper end of the subumbrella;
mouth with 4 everted lips: North Atlantic; often
common on the New England coast.

3. PERSA McCrady. But 2 gonads present,
which are thick and elongate and on opposite sides of the umbrella;
8 lithocysts; numerous tentacles: 1 species.

P. incolorata McCr. Bell thimble-shaped and colorless; gonads
yellowish; tentacles long and brittle and easily broken off; 3 mm. high
and half as wide: coasts of North and South Carolina; rare.

FAMILY 3. GEEYONIIDAE.

Trophosome: wanting. Gonosome: medusa
hemispherical; manubrium very long; 6 or 8 en-
closed lithocysts ; radial canals 4 or 6 ; gonads plate-
like : 2 genera.

LIRIOFE Lesson. Manubrium extending far
beyond the velum and with a square mouth; 4
radial canals, between each pair of which are 1
to 3 centripetal (f. e., extending from the circular
canal upwards) canals, and 4 to 12 tentacles: 20
species.

L. exigua (Quoy and Gaimard) (Fig. 202).
Bell hemispherical, 20 mm. wide: Gulf Stream;
Mediterranean; occasionally on the New England
coast.

ORDER 6. NARCOMEDUSAE.

Fig. 202

Liriope exigua
(Mayer).

Trophosome: wanting, so far as known, development being direct,
the animals living in the open ocean. Gonosome: medusa with lobed

NARCOMEDUSAE 121

margin ; tentacles stiff and extending from the exurabrella ; gonads on the
subumbrella ; gastrovascular cavity a wide central space, either circular
in outline or with radial pouches or canals extending outwards; ring
canal follows the marginal lobes but is often absent; lithocysts free
and often projecting, with entodermal concretions; a thickened ecto-
dermal ring is at the edge of the umbrella with prolongations called
peronia extending to the base of the tentacles, and often others also,
called otoporpae, extending upwards from the base of the lithocysts:
2 families and 50 species, of which a few are found along our coast.

FAMILY ^EGINIDAE.

Radial pouches of gastrovascular space present : 11 genera.

1. CUNOCTANTHA Haeckel. Tentacles, marginal lobes, and radial
pouches 8; otoporpae present; the larvae live parasitically in the bell
of the mother or some other medusa where they bud off new larvae from
a stolon-like prolongation of the apical

end of the umbrella: 5 species.

0. octonaria McCrady (Fig. 203).
Diameter 7 mm. ; manubrium cone-shaped
with 4 lips: common at Beaufort, North
Carolina, the larvae infesting Turritopsis
nutricula; cosmopolitan.

2. CTJNINA Eschscholtz. Tentacles

and radial canals 9 to 24; the larvae live parasitically in the bell of the
mother or some other medusa : 10 species.

C. lativentris Gegenbaur. Medusa flat, transparent, about 16 mm. in
diameter; tentacles, marginal lobes, and stomach pouches 10 to 12; litho-
cysts on each lobe 4: Atlantic Ocean and Mediterranean Sea.

Order 7. SIPHONOPHORA.*

Free-swimming, colonial Hydromedusae. The individuals forming a
colony are in a high degree polymorphic, there being several orders of
individuals all of which are in communication with one another by means
of the common gastrovascular space. Each order performs a distinct
function in the colony, the division of labor being similar to that which
obtains among the various organs of the body of one of the higher 'animals.
Two general types of structure are met with among the SiphonopJiora. In
one (Fig. 204) the various individuals bud off from a long axial tube,

* See "The Siphonophorae of the Challenger," by E. Haeckel, Challenger
Reports, Vol. 28, 1888.

122

C(ELENTEEATA

A -I

the upper end of which is expanded to form a float called the pneurnato-
phore which contains air or a gas and serves to keep the colony right
side up in the water: in the other type (Fig. 205) no such axial tube
is present, the various individuals budding off from the under side of
the enormously enlarged float. By far the greater
number of siphonophores are of the first type. The
individuals budding off from the axis immediately
back of the pneumatophore are swimming individ-
uals or nectophores; these are present in pairs, and
each Has the form of a hydrozoan medusa without
the manubrium. Following the nectophores at in-
tervals on the axis are similar groups of individuals,
each group consisting usually of (1) the bract, a
flat, scale-like protective individual; (2) a club-
shaped palp; (3) a nutritive individual or gastro-
zooid, which is the mouth and stomach of the colony ;
(4) a long tentacle with nematocysts; (5) repro-
ductive individuals or gonozooids, which are usually
unisexual. A colony of this kind swims about slowly
in the sea and may be several feet in length and
contain thousands of individuals. A modification of
this type is seen in the deep-sea siphonophores of
the genera Stephalia and Bhodalia, in which the
pneumatophore is very large and the axis short and

thick. In Stephalia a mouth is present at the terminal end of the axis,
which forms the chief gastrozooid: the axis is thus in this case directly
comparable with the manubrium of a medusa,
of which the pneumatophore would be the bell.
In Rhodalia the axis has lost its character of a
gastrozooid, not having a mouth at the lower
end. These animals are probably primitive
siphonophores and seem to indicate the deriva-
tion of the group from a medusan instead of
from a mixed hydroid and medusan stock. They
also form a connecting link between the two
general types of Siphonophom, those with an
axial tube and those which have none.

Siphonophores are essentially pelagic animals, although some forms
are found in deep water. They belong to the open ocean, especially of
the warmer parts of the world, and are among the most beautiful and
conspicuous animals found there. The order contains about 250 species,
grouped in 4 suborders.

Fig. 204 — Diagram
of a siphonophore (Mc-
Murrich). 1, pneuma-
tophore ; 2, necto-
phore ; 3, bract ; 4,
gonozooid ; 5, gastro-
zooid ; 6, club ; 7, ten-
tacle.

Fig. 205

Diagram of a Porpita
(Delage et H6rouard).

SIPHONOPHOEA 123

Key to the suborders of Siphonophora :

ot Pneumatophore present.
&! Pneumatophore very large ; nectophores absent.

ct Pneumatophore a disc, with a large central gastrozooid 1. DISCONECTAE

c2 Pneumatophore more or less cylindrical, without a large central gas-
trozooid 2. CYSTONECTAE

&2 Pneumatophore usually small ? nectophores present ; colony usually

elongate 3. PHYSONECTAE

a, Pneumatophore absent ; nectophores very large ; colony swimming rapidly.

4. CALYCONECTAE

SUBORDER 1. DISCONECTAE.

Siphonophores with a very large disc-like pneumatophore and with-
out swimming individuals (Fig. 205). The pneumatophore has a com-
plex structure; it contains a number of air chambers and beneath its
center is a single large trunk which bears the principal mouth and
stomach of the colony. Surrounding the trunk are small reproductive
individuals which bear the gonads, and surrounding them near the rim
of the disc are long dactylozooids or tentacles armed with nemotocysts.
The whole colony bears a striking resemblance to a medusa: 36 species,
grouped in 2 families.

FAMILY VELELLIDAE.*

Pneumatophore a circular or elliptical disc without marginal inden-
tations: about 30 species.

1. VELELLA Bosc. Disc elliptical and very flat and with an ele-
vated ridge passing diagonally across it, which acts as a sail as the
animal floats on the surface of the water: 13

species.

V. mutica Bosc (Fig. 206). Length of
disc 4 cm., breadth 2 cm. : along the South
Atlantic coast, occasionally off New England.

2. PORPITA Lamarck. Disc circular, and Fig. 206 — Velella mutica

(from Lankester).
without the sail: 8 species.

P. linnseana Lesson (Fig. 205). Diameter of disc 3 to 5 cm.: along
the South Atlantic coast, occasionally off New England.

SUBORDER 2. CYSTONECTAE.

Siphonophores with a very large pneumatophore from the under side
of which project nutritive individuals, no large central trunk and no
swimming individuals being present. The colony floats on the surface
of the water, often carried by currents and the wind long distances,
and can sink beneath the surface by compressing the pneumatophore

* See "The Porpitidae and Velellidae," by A. Agassiz, Mem. Mus. Comp. Zool.,
Vol. 8, 1883.

124

COSLENTEEATA

and driving out the air or gas through a pore in its upper side. In
order to rise to the surface again it fills the pneumatophore with a self-
generated gas. The suborder contains 30 species grouped in 5 families.

FAMILY PHYSALIIDAE.

With the above-described characters : 4 genera and 10 species.

PHYSALIA Lamarck. Pneumatophore
with a dorsal crest with transverse septa:
4 species.

P. pelagica Bosc. Portuguese man-of-
war (Fig. 207). Pneumatophore up to 12
cm. long, pear-shaped with iridescent col-
ors; tentacles long, sometimes stretching
10 or 15 meters, and with powerful stinging
organs: in the Gulf Stream from Florida
to Vineyard Sound and occasionally to the
Bay of Fundy; often common.

SUBORDER 3. PHYSONECTAE.

Fig. 207

PhysaUa pelagica
(Lankester).

Siphonophores with a pneumatophore
with a long trunk or axis from which bud
off nectophores and successive similar

groups of individuals, each group containing usually a bract, a gastro-
zooid, a palp, a tentacle, and a gonozooid: 9 families and about 75
species.

FAMILY AGALMIDAE.

Two longitudinal rows of alternating nectophores; trunk long, bear-
ing numerous groups of individuals: 30 species.

CTTPULITA Quoy and Gaimard (Nanomia A. Agassiz). Four to 6
nectophores in each row; individual groups not all of the same impor-
tance, there being secondary groups lacking the gastrozooids between
the principal groups: several species.

C. cara (A. Ag.). Length of colony about 11 cm.: Newport and
Massachusetts Bay.

SUBORDER 4. CALYCONECTAE.

Siphonophores with very large swimming individuals (nectophores)
and without pneumatophore or palps, the individual groups consisting
each of a nutritive and one or more reproductive individuals, a covering
bract, and a short tentacle. The colony swims rapidly, in contrast to
most Siphonophores, being partly sustained by a drop of colored oil
present in each nectophore: 5 families and 95 species.

SC7PHOZOA

125

Fig. 208

FAMILY DIPHYIDAE.

Two neetophores present: 10 genera and about 35 species.

DIPHYES Cuvier. Neetophores conical and very large; the remain-
der of colony can be retracted into a groove in the neetophores and is
constantly being shortened by the breaking off of
the terminal and oldest groups of individuals, each
group (which is called an Eudoxia) thus separated
leading an independent life and becoming sexually
mature: 6 species.

D. bipartita Costa (Fig. 208). Total length 30
mm. ; length of the neetophores 10 mm. ; body trans-
parent: tropical and subtropical Atlantic; Mediter-
ranean; occasionally on New England coast; often
very common.

CLASS 2. SCYPHOZOA. (SCYPHOMEDUSAE.)

These animals have usually an alternation of
generations, in a few (Pelagia), however, the medu-
soid generation and in others (Lucernaria) the
hydroid alone being present. The medusoid plays
a much more conspicuous part than the hydroid.
The latter is a small, usually non-colonial animal
called the scyphistoma, which is less than a centimeter in height and
resembles the fresh-water Hydra in appearance (Fig. 217, A). It differs
from Hydra, however, in that the aboral end is fixed to the bottom in a
cup formed of the perisarc, in the possession of four longitudinal folds
of the entoderm called mesenteries which project into the gastrovascular
space and of an ectodermal gullet. The scyphistoma is an asexual
animal and reproduces by budding exclusively. New scyphistomas may
be produced by a process of lateral budding from stolons sent off from
the foot. The medusoid generation is produced by a process of terminal
budding called strobilation (Fig. 217, B). The scyphistoma grows in
height and a series of constrictions appear which divide it into a number
of discs. Each disc is called an ephyra (Fig. 217, C) and is a young
medusa or jellyfish, which on becoming free grows in time to be a sexual
animal.

The medusa which is thus produced is often a large animal; Cyanea
may be two meters and more in diameter with tentacles thirty-five
meters or more long. It is called acraspedote because the velum, which
is so characteristic of the craspedote Hydromedusae, is wanting or
rudimentary. The periphery of the bell is lobed or scalloped and may
or may not have tentacles. The manubrium is sometimes very long and

Diphyes bipartita
(Har

targitt).

126 CCELENTERATA

large and extensively branched and in the Rhizostomata the mouth is
closed by the coalescence of its sides, small pores remaining through
which nutriment is taken in. The gastrovascular space is complex in
form and usually consists of four radial pouches forming a large space
in the center of the animal and additional radial canals which often
branch and may be joined at their outer ends by a circular canal.

The gonads are four in number and often brightly colored; they
are specialized portions of the entoderm and appear in the interradii of
the gastrovascular space. In many species four large pockets, called the
subgenital pockets (Fig. 216, S) and probably respiratory in function,
are present in the subumbrella directly beneath the four gonads. Beside
each gonad are usually a number of cylindrical mesenterial filaments,
armed with nettle organs.

The finer structure of the Scyphozoa is essentially like that of the
Hydrozoa. The mesoglea is different, however, in that it is much firmer
and usually cellular. The sense organs are also different, being perhaps
modified tentacles, and are called tentaculocysts or rhopalia.

The Scyphozoa are all marine and among the most familiar animals
along our shores. The class contains 5 orders and about 180 species.

Key to the orders of Scyphozoa:

at Body stalked and sessile, there being no medusa stage .... 1. STAUBOMEDUSAE
Oj Free-swimming medusae present.

&! Medusa with distinct constriction about its middle 2. COEONATAE

&2 No such constriction present.

G! Tentacles present either on the margin or the subumbrella.
di Medusa cuboidal in shape with 4 long marginal tentacles or groups of

them 3. CUBOMEDUSAE

da Medusa with 8 or more tentacles on margin or subumbrella.

4. SEM^EOSTOMEAE
c2 No tentacles on margin or subumbrella 5. RHIZOSTOMAE

ORDER 1. STAUROMEDUSAE.

Body conical in shape with aboral surface usually drawn out to
form a stalk by which it is temporarily attached, representing a sexual
scyphistoma ; margin with 8 prominent lobes, each with a cluster of short
knobbed tentacles; without sensory organs but often with marginal
adhesive pads (marginal anchors) in the angles between the lobes: 25
species and 2 families, the animals usually attached to seaweed in
shallow water.

FAMILY LUCERNAEIIDAE.*

Margin with 8 lobes, each with numerous knobbed tentacles; animal
attaches itself temporarily to algae, along which it crawls : 5 genera.

* See "Lucernariae and Their Allies," etc., by H. 3. Clark, Smithsonian Contrib.
to Knowledge, Vol. 23, 1878.

SCYPHOZOA

127

Key to the genera of Lucernariidae here described :

cx Adhesive pads absent 1. LUCEBNABIA

a2 Adhesive pads present.

61 Stalk quadrate 2. HALICLYSTUS

62 Stalk cylindrical 3. HALIMOCYATHUS

1. LUCERNARIA 0. F. Miiller. Marginal adhesive pads absent; stalk
cylindrical: 8 species, 1 American.

L. quadricornis Mull. Height 7 cm.; diameter 5 cm.; color green,
gray, or reddish; tentacles on each lobe 100 or more: Cape Cod to
Greenland; Europe.

2. HALICLYSTUS Clark. Eight
marginal adhesive pads between
the lobes; stalk quadrate: 6 spe-
cies, 2 American.

H. auricula Clark (Fig. 209).
Height and diameter 3 cm.; color
variable; tentacles on each lobe
100 or more: Cape Cod to Green-
land; Europe; Alaska.

H. salpinx Clark. Height 20
mm.; diameter 25 mm.; tentacles
slender, about 70 on each lobe;
marginal pads very large and as

long as the tentacles: Cape Cod to Fjg 20a_Haltcllistus auricula (Mayer).
Greenland; Adriatic Sea.

3. HALIMOCYATHUS Clark. Marginal adhesive pads present; 4
gastrogenital pockets present in subumbrella wall of the gastrovascular
pouches; stalk cylindrical: 2 species.

H. lagena (Haeckel). Height 3 cm.; diameter 7 mm.; tentacles on
each lobe 70: Cape Cod to Greenland; rare; Europe.

ORDER 2. CORONATAE.

Medusa with a constriction about its middle; margin in most cases
with 16 lobes, long tentacles and rhopalia: 5 families and 27 species,
which are usually found in the open ocean.

FAMILY 1. PEEIPHYLLIDAE.

Marginal lobes 16; tentacles 4 or more; rhopalia 4: 4 genera and
8 species.

PERIPHYLLA Steenstrup. Twelve tentacles; body conical; 4 deep
subgenital pockets (funnels); gonads horseshoe-shaped: 3 species.

128

CCELENTERATA

P. hyacinthina Steen. (Fig. 210). Medusa about 8 cm. high and 4
cm. wide; color reddish: Greenland; Gulf Stream; cosmopolitan.

Pig. 210 Fig. 211

Fig. 210—Periphvlla hyacinthina, (Mayer). Fig. 211—Nausithoe punctata (Mayer).

FAMILY 2. EPHYEOPSIDAE.

Usually 16 marginal lobes; 9 rhopalia and 8 or more tentacles:
3 genera and 11 species.

1. NAUSITHOE Kolliker. Gonads 8; tentacles 8; marginal lobes 16;
ectoderm of bell with clusters of small crystals: 6 species.

N. punctata Roll. (Fig. 211). Medusa 10 mm. broad and 4 mm.
high; marginal tentacles stiff: cosmopolitan; Gulf Stream; common.

2. LINTTCHE Eschscholtz. Similar to
Nausithoe but with sac-like gastric pouches :
2 species.

L. unguiculata Eschs. (Fig. 212).
Medusa cylindrical or thimble-shaped, 13
mm. high and 16 mm. wide: Gulf stream;
often in swarms.

Fig. 212 — Linuche unguiculata
(Mayer).

ORDER 3. CUBOMEDUSAE.

Body more or less cuboidal in form,
with a single interradial tentacle or a
group of tentacles at each of the 4 corners,
the bases of which are in most forms
expanded to form prominent flattened

structures called pedalia; rhopalia 4, between the tentacles; 4 wide gas-
tric canals in which are the plate-like gonads; false velum (velarium)
present, which together with their energetic swimming movements gives
the animals the appearance of craspedote medusae: 1 family and about
16 species.

SCYPHOZOA

129

FAMILY CHARYBDEIDAE.

With the characters of the order: 6 genera.

1. TAMOYA F. Miiller. Four tentacles, with prominent pedalia; 4
clusters of gastric cirri: 1 species.

T. haplonema F. Miil. (Fig. 213). Medusa 9 cm. high and 5 cm. in
diameter; exumbrella covered with wart-like
clusters of nematocysts : Long Island Sound
to West Indies.

2. CHIROPSALMUS Agassiz. Four groups
of about 8 tentacles each, each group ex-
tending from the fingers of a palmate peda-
lium; finger-like sacs extending into the cav-
ity of the bell from near the base of the
manubrium: 4 species.

C. quadrumanus Ag. Medusa 10 cm.
high and 14 cm. in diameter: North Caro-
lina and southwards, often common in
shallow water. Fi*- 213-T^noya haplonema

ORDER 4. SEM.EOSTOMEAE.

Mouth quadrate, with 4 long, oral lobes, often folded and frilled;
marginal tentacles hollow, often very long; rhopalia marginal: 3 families.
Key to the families of Sem&ostomeae:

0! Very long marginal tentacles 1. PELAGIIDAE

O2 No long marginal tentacles.

&! Long tentacles on subumbrella ; no marginals .2. CYANEIDAE

&2 Short marginal tentacles 3. ULMABIDAE

FAMILY 1. PELAGIIDAE.

Large, brightly colored medusae, disc-like
or hemispherical in form, with wide, simple,
radial gastral pouches and no ring canal, and
very long oral lobes and marginal tentacles:
5 genera and 18 species.

1. PELAGIA Peron and Lesueur. Eight ten-
tacles and 8 rhopalia; 16 marginal lobes; exum-
brella covered with warts of nettle cells; devel-
opment direct, no hydroid stage being present:
7 species.

P. cyanella Per. and Les. (Fig. 214). Diam-
eter 5 cm. ; height 4 cm. : coast of Florida and the Carolinas, occasionally
appearing as far north as New England.

Fig. 214 — Pelagia cyanella
(Mayer).

130

CCELENTEEATA

2. DACTYLOMETRA Agassiz. Forty marginal tentacles; 8 rhopalia;
48 marginal lobes: 5 species.

D. quinquecirrha (Desor). Diameter up to 25 cm.: Long Island
and Vineyard Sounds to the tropics.

Fig. 215— Cyanea capillata var.
artica (Mayer), showing the sub-
umbrella with the tentacles and
the oral lobes partly removed. 1,
5, gonad ; '

oral lobe ; 2,

3, tentacles.

FAMILY 2. CYANEIDAE.

Large disc-shaped medusae; radial pouches of the gastrovascular
cavity very wide and ramifying at their distal ends; no ring canal and

no subgenital pouches: 4 genera, con-
taining the largest medusae; 6 species.
CYANEA Peron and Lesueur. Eight
groups of very long tentacles which ex-
tend from the subumbrella; oral lobes
very long, wide, and voluminous, between
which and the tentacles are the 4 large
bunches of gonads which have evagi-
nated from the gastrovascular cavity;
8 rhopalia in as many marginal indenta-
tions: 2 species.

C. capillata (L.) var. arctica Per. and
Les. (Fig. 215). Disc usually 10 to 50
cm. in diameter, but specimens 2 m. in
diameter have been seen with tentacles 40 m. long; color variable, usually
purplish red or brown ; the largest jellyfish : common from North Carolina
to Greenland; a light-brown variety called C. fulva Agassiz occurs in
Long Island Sound, and a bluish-white variety called C. versicolor Ag. off
the Carolina coast.

FAMILY 3. ULMAKIDAE.

Radial canals nar-
row and branching,
forming a complex sys-
tem with a circular
canal joining the distal
ends : 10 genera and 17
species.

AURELIA Peron
and Lesueur. Oral
lobes long and rather
narrow; marginal ten-
tacles minute; body flat and disc-like; 4 large subgenital pockets; 8
rhopalia in as many marginal indentations: 5 species.

Fig. 216 — Aurelia aurita var. flavidula (Mayer).
s, subgenital pockets ; o, oral lobes.

SCJPHOZOA

131

Pig. 217 — Young stages of Aurelia aurita
var. flavidula (Agassiz). A, a scyphistoma ;
B, a young strobilia ; C, an ephyra.

A. aurita (L.) var. flavidula Per. and Les. (Figs. 216 and 217). Disc
may be 30 cm. or more in diameter; color white or bluish with pink
gonads : very common along the entire Atlantic coast, breeding through-
out the summer, the scyphis-
toma stage lasting throughout
the winter.

ORDER 5. RHIZOSTOMAE.

Marginal tentacles absent;
8 oral lobes very large and much
branched extend from the cen-
ter of the subumbrella with
sucking pores along their edges
which take the place of a mouth,
the mouth being usually obliter-
ated; oral tentacles border the
pores: 63 species.

1. STOMOLOPHTTS Agassiz.
Body hemispherical; the fused
oral lobes form a thick cylinder at the bottom of which are 8 pairs of
frilled lobes and a central mouth opening; 8 rhopalia: 1 species.

S. meleagris Ag.
(Fig. 218). Diameter
18 cm.; color of exum-
brella brown : from
Florida to North Caro-
lina and occasionally to
the coast of New Eng-
land; often common.

2. RHOPILEMA
Haeckel. Body hemi-
spherical; 8 separated,
3- winged oral lobes
from which numerous
club-shaped filaments
hang: 3 species, one of
which, R. esculenta, is
Fig. 218— Stomolophus meleagris (Mayer). the edible jellyfish of

China and Japan.

R. verrilli (Fewkes). Diameter 35 cm.; 8 rhopalia; color yellowish:
Long Island Sound to North Carolina and southwards.

132

CCELENTERATA

Fig. 219 — Diagram of a longitudinal
section of a coral animal (Boas). 1, ten-
tacle ; 2, mouth ; 3, gullet; 4, mesentery ;
5, base of a mesentery which has been cut
away ; 6, septum of the calcareous skele-
ton covered by a fold of the foot ; 7, theca;
8, septum.

CLASS 3. ANTHOZOA. (ACTINOZOA.)

Corals, sea anemones, etc. Coe-
lenterates in which the polyp form
alone is present, no medusa gener-
ation appearing. The body (Fig.
219) is usually cylindrical in form
and is attached either permanently
or temporarily at one end, which,
in the sea anemones, is called the
foot or pedal disc. The other and
flattened end is the oral disc; in its
center is the mouth surrounded by
hollow tentacles, which may num-
ber from six to several hundred.
The mouth is not round, but an
elongated slit, at one or both ends
of which is a prominent, ciliated

groove called the siphonoglyph, through which the genital products may

reach the outside (Fig. 220). The mouth does not lead directly into the

gastrovascular space, but into a

tube lined with ectoderm called the

gullet which opens into the gastro- *

vascular cavity below. This cavity

is divided into a number of com-
municating chambers by six or

more wide longitudinal ridges called

the mesenteries, which spring from

the body wall and project towards

the center of the cavity; in the

upper portion of the body, certain

of these mesenteries join the body

wall with the wall of the gullet

(Fig. 220), thus dividing this part

of the gastrovascular space into

small chambers which are continued

above in the hollow tentacles, while

in the lower portion of the gastro-
vascular space the edges of the mes-
enteries are free.

Along the free edge of each mesentery is a convoluted thickening, the

mesenterial filament, which is of great importance inasmuch as it contains

—2

Fig. 220 — Diagram of a cross section
of an anthozoan through the gullet
(Weysse). 1, siphonoglyph; 2, gullet;
3, primary mesenteries ; 4. secondary
mesenteries ; 5, tertiary mesenteries ; 6,
longitudinal muscle.

ANTHOZOA 133

the gonads, and also nematocysts; at its lower end also, in many species,
are long threads called acontia charged with nematocysts which can be
protruded from the mouth and also, in some cases, through pores (cin-
clides) in the body wall. The mesenteries bear the retractor muscles, each
of which appears as a prominent ridge on one side of it. At the upper end
of the body is usually a strong sphincter muscle which draws this end
together and closes the mouth. The body wall consists of the two main
cell layers and the mesoglea, which contains nuclei. The mesenteries are
composed of mesoglea and entoderm; the important retractor muscles and
the gonads being thus of entodermal origin, the latter migrating later
into the mesoglea of the mesenteries where they are found.

Very characteristic is the skeleton, which most Anihozoa possess. This
is composed either of calcium carbonate or a horn-like substance called
ceratine, both of which are secreted by the ectoderm and serve to elevate
the colony in the water, bringing it into a favorable position for main-
taining itself.

The Anihozoa are in most cases unisexual. The ova and sperm are
thrown into the gastrovascular space, where in many cases a portion of
the development may be carried on. In some sea anemones, the young are
carried awhile in pits on the side of the body. After a short free life, the
young animal settles to the bottom, and in most cases becoming fixed,
develops into the adult animal. Asexual reproduction by budding is very
general and leads to the formation of the colonies which are so character-
istic of the group. All of the Anihozoa are marine animals and are espe-
cially numerous in the warmer parts of the world. Corals are of impor-
tance to man because of the coral reefs, banks, and islands they help to
form. The only species which have commercial importance are the red
corals of the Mediterranean and Japan which are used in the manufacture
of jewelry. The name of the class originated with Ehrenberg, who in
1831 divided the polyps as then known into two groups, the Anihozoa or
flower animals and the Bryozoa or moss animals. The class contains
over 2,000 living and many fossil species, which are grouped in two
orders.

Key to the orders of Anihozoa:

a-! Eight pinnate tentacles present 1. ALCYONARIA

oz Tentacles simple and usually numerous 2. ZOANTHABIA

ORDER 1. ALCYONARIA.*

Colonial Anihozoa with 8 pinnate tentacles and 8 mesenteries (Fig.
222, B). A siphonoglyph is present on but one side of the polyp, or not
at all. The retractor muscles are all on the same side of the mesen-

* See "Alcyonaria of Porto Rico," by C. W. Hargitt and C. R. Rogers, Bull. U.
S. Fish. Com., Vol. 20, p. 267, 1900.

134 CCELENTEEATA

teries, that which looks towards the siphonoglyph. The skeleton con-
sists of calcium carbonate or ceratine spicules imbedded in the mesoglea,
but formed by cells of ectodermic origin, which may be fused together in
the center of the colony so as to form a compact axis : in a few genera
a skeleton is lacking. The mesoglea, stiffened thus by the spicules,
together with the outer ectoderm, is called the coenenchym. The polyps
are seated in depressions in the ccenenchym, into which they can usu-
ally retract, and are in communication with one another by means of
entodermal canals (Fig. 222, B). The Alcyonaria are often brightly col-
ored and phosphorescent and are among the most conspicuous objects in
the tropical seas. The order contains about 33 families and over 600 living
species, grouped in 5 suborders.

Key to the suborders of Alcyonaria here described:

Oj Colony fixed and stationary.

Z>! Polyps rise from a stolon 1. STOLONIFERA

52 Colony erect.

GI Central skeletal axis absent 2. ALCYONACEA

c2 Central skeletal axis present 3. GORGONACEA

a2 Colony not fixed or stationary 4. PENNATULACEA

SUBORDER 1. STOLONIFERA.

Colony consists of independent polyps which rise from a mem-
branous or ribbon-like stolon; they are not continuously joined but may
be united by transverse tubes or plates: 3 families.

FAMILY CORNULARIIDAE.

Polyps not joined together except by the creeping stolon from which
they spring; spicules usually absent: about 15 genera.

CORNTJLAEIELLA Verrill. Upper portion of polyp retractile into the
rigid lower portion; spicules present: 1 species.

C. modesta Ver. Polyps 6 to 18 mm. high and 3 mm. in diameter;
color of stolons and lower part of polyps yellow or brown : Casco Bay to
Gulf of St. Lawrence, from 30 fathoms to deep water.

SUBORDER 2. ALCYONACEA.

Colony usually branching, without central axis; coenenchym with
spicules and usually fleshy: about 10 families and over 100 species.

FAMILY 1. ALCYONIIDAE.

Colony simple or branching and more or less massive; polyps elon-
gate and joined by entodermal canals; coenenchym with numerous
spicules: about 12 genera.

ALCYONIUM L. Colony composed of short, thick lobes and soft or
leathery; polyps long and, with the exception of the outer end with the

ANTHOZOA 135

tentacles, entirely buried in the mass of the ccenenchym which forms
the bulk of the colony: numerous species.

A. carneum Agassiz. Colony yellowish or reddish in color, lobed
or arborescent and 4 to 10 cm. high: from Long Island Sound to Gulf
of St. Lawrence, from low water to 80 fathoms.

FAMILY 2. NEPHTHYIDAE.

Colony more or less dendritic, consisting of a sterile trunk and
branches bearing polyps; consistency soft and leathery; polyps not
retractile, with tentacles folded over oral disc when at rest: 10 genera.

SPONGODES Lesson. Colony massive or dendritic; spicula in periph-
ery of polyps so numerous that neither the polyp nor their tentacles
are retractile; polyp surrounded by giant spicules which project from
its base beyond the tentacles: 40 species.

S. portoricensis Hargitt. Colony about 45 mm. high, whitish in
color, densely spinose: near Porto Rico, in 75 fathoms.

SUBORDER 3. GORGONACEA.

Sea fans, sea whips, red coral, etc. Colony usually branching exten-
sively and with a central skeletal axis, composed of compacted spicules,
which is either calcareous, horn-like, or composed of calcareous alternating
with horn-like segments; a rind of coenenchym containing spicules covers
this axis, in which the polyps are imbedded, being joined together by
entodermal canals: about 11 families and over 250 species.

FAMILY 1. COEALLIIDAE.

Colony erect, branching, with a dense, calcareous axis of fused
spicules surrounded by canaliferous coenenchym bearing spicules: about
3 genera.

CORALLITTM Lamarck. Red coral. Polyps white in color and re-
tractile; spicules and axis red; axis thick and longitudinally ridged by
entodermal canals, very hard, forming the red coral of commerce: about
a dozen species, in the Mediterranean, eastern Atlantic, and off the coast
of Japan.

C. nobile (Pallas) (C. rubrum Lam.). Colony up to 30 cm. high: in
the central and western Mediterranean, being fished principally off the
coast of Africa and Italy.

FAMILY 2. GORGONIIDAE.

Colony erect and branched, often in one plane; axis horn-like, occa-
sionally horn-like and calcareous; polyps occur in rows and on two sides
only of the stem and branches: 12 genera.

136

CCELENTEEATA

GORGONIA L. Colony arborescent, often fan-shaped, the branches
being in the same plane and often anastomosing so as to form a network ;

polyps retractile: numerous species.

G. flabellum L. Sea fan (Fig. 221).
Colony a network with meshes 2 to 6 mm.
wide, yellowish or reddish in color and up to
50 cm. high and wide: South Atlantic and
West Indies, in shallow water.

G. acerosa Pallas. Colony dendritic,
with long, slender branches, the smaller
branches being arranged pinnately, up to 80
cm. high, straw-colored: West Indies, in shal-
low water.

Gorgonia flaftellum
(Hargitt).

FAMILY 3. PLEXAUKIDAE.
Fig. 221

Colony branched and erect, with the
polyps scattered over entire surface; axis
horn-like or horn-like and calcareous; coenenchym thick; polyps rather
large and projecting: 10 genera.

1. EUNICE A Lamouroux (Fig. 222). Colony arborescent; trunks
cylindrical; polyp edges bilobed or crenate;
axis horn-like: numerous species.

Fig. 222 — Eunicea. A, (Hargitt) entire colony; B, (Chester) cross section showing
polyps. 1, expanded polyp ; 2, longitudinal section of polyp ; 3, con-
tracted polyp ; 4, central axis ; 5, entodermal canal.

ANTHOZOA 137

E. crassa Edwards and Haime. Colony up to 50 cin. high and half
as broad; diameter of trunks 8 to 15 cm.; coenenchym thick, corky:
West Indies.

2. PLEXAURELLA Kolliker. Colony arborescent; trunks cylindrical;
axis horn-like and calcareous; cup edges smooth; coenenchym usually
very thick.

P. dichotoma Dana. Stem 12 to 20 mm. thick; branches smooth,
club-shaped; color brownish: West Indies; very common.

SUBORDER 4. PENNATULACEA.*

Sea pens and sea feathers. Colony not fixed, but capable of inde-
pendent movement and consisting of two parts, a stalk which is im-
bedded in sand or mud, and an upper part called the rachis, which bears
the polyps and may have the form of a feather, a rod, a broad plate; a
central calcareous or horn-like axis usually present ; outer layer of mesoglea
permeated with spicules forming a crust; polyps
large and in communication with one another by
entodermic canals and dimorphic, the autozooids
being of ordinary structure, the smaller siphono-
zooids having no tentacles or gonads and reduced
mesenteries and serving for the inflow and outflow
of water through the entodermal canals : 15 families
and over 200 species.

FAMILY 1. PENNATULIDAE.

Sea feathers. Rachis elongate with paired lat-
eral branches or pinnulae; siphonozooids confined
to lower side of rachis : about 4 genera.

PENNATTJLA Lamarck. Pinnulae long, from 20
to 50 in number on each side, bearing the autozooids
on their upper margin: several species.

P. aculeata Danielsen (Fig. 223). Length 10
cm.; rachis with numerous spines among the sipho-
nozooids ; color deep red, stalk rose-colored, becom- FIs- 223
ing whitish at the base: Gulf of St. Lawrence to Pennatui^aculeata
Carolina, in 100 to 500 fathoms; common; Europe.

P. grandis (Ellis) (P. borealis Sars). Length up to 50 cm.; color
orange; breadth 14 cm.: Newfoundland to Nantucket, in 100 to 600
fathoms.

* See "Die Pennatuliden," by A. Kolliker, Frankfort, 1870.

138 C(ELENTERATA

FAMILY 2. FUNICULINIDAE.

Sea pens. Stalk short and thicker than the quadrangular rachis
which is long and slender and bears the autozooids in oblique rows;
autozooids retractile; siphonozooids confined to lower side of rachis:
1 genus.

FUNICULINA Lamarck. With the characters of the family : 2 species.
F. armata Verrill. Length up to 60 cm.; auto-
zooids deep purple; rachis yellowish below and
brownish above: Newfoundland to Nantucket, in
100 to 400 fathoms.

FAMILY 3. EENILLIDAE.

Rachis broad and circular or reniform, with
the polyps confined to the upper surface; no axial
skeleton: 1 genus.

Fig. 224

Renilla reniformis RENILLA Lamarck. With the characters of the

(CammsdtoryI)atural family: 10 species.

R. reniformis (Pallas) (Fig. 224). Upper part

pink or violet in color, polyps white; 7 cm. long: on the Carolina coast,
in shallow water; West Indies.

ORDER 2. ZOANTHARIA.

Stony corals 'and sea anemones. AntJiozoa, often of large size, most
of which secrete a stony or horn-like skeleton. The tentacles are usually
simple (in the Australian sea anemone, Actinodendron, branched) and may
number from six to several hundred.

The mesenteries (Fig. 220) are usually numerous, consisting of six
primary pairs (protocnemes) which alone are present in the most primi-
tive forms, and numerous secondary mesenteries (metacnemes) which
are usually unilateral, that is, in pairs, both members of which are on the
same side of the gullet, and arise in series, the younger and smaller pairs
appearing between the older and larger ones. The gullet is joined with
the body wall by all of the protocnemes (except in Edwardsia) and usually
by certain of the metacnemes, the two pairs of protocnemes which join
the siphonoglyphs with the body wall being called the directives. The order
contains 1,500 species, grouped in three suborders.

Key to the suborders of Zoantharia:

Oj Skeleton present ; animals mostly colonial.

61 Skeleton horn-like 1. ANTIPATHAEIA

62 Skeleton calcareous 3. MADBEPORABIA

a, No skeleton ; animals mostly solitary 2. ACTINIABIA

ANTHOZOA 139

SUBORDER 1. ANTIPATHARIA.

Black corals. Colonial Zoantharia having the appearance of alcyona-
rians, with a black, horn-like central axis and a thin comenchym in which
are no spicules; polyps usually with 6 tentacles and 6 mesenteries: 3
families with about 100 species, most of which live in the deep sea.

FAMILY ANTIPATHIDAE.

Colonies composed of long, slender stalks and branches; polyps
with 6 tentacles, 6 primary mesenteries, and with or without 4 or 6
secondary mesenteries; axis beset with spines and with a central canal:
about 30 species.

1. ANTIPATHES Pallas. Colony branching; axis with long, numer-
ous spines: about 15 species.

A. larix Esper. Colony up to 1 m. high and composed of a few
long main stalks each bearing 6 longitudinal rows of parallel branches
from 3 to 10 cm. long: West Indies; Mediterranean.

2. CIRRIPATHES Blainville. Colony not branched but consisting of
a simple long and flexible and often spiral stalk: several species.

C. spiralis (L.). Colony a meter or more long and spiral: West
Indies; Mediterranean; Indian Ocean.

SUBORDER 2. ACTINIARIA.*

Sea anemones. Skeleton not present; animals usually solitary;
often very brightly colored and of large size, occurring in all parts of
the world, in all depths of water; the animals usually attach themselves
temporarily to some more or less stationary object by the broad sucker-
like foot, but can usually move about slowly; some live in the sand and
a few are free-swimming: about 400 species, grouped in 4 divisions.

Key to the divisions of Actiniaria:

Q! Eight longitudinal ridges on the outer surface of the body 1. EDWABDSIAE

a2 At least 12 ridges or none at all.

&! But 2 rows of tentacles, an outer marginal and an inner. .2. CERIANTHEAE
&2 Tentacles not in two rows.

(?! Animals colonial 3. ZOANTHEAE

c2 Animals solitary 4. HEXACTINIAE

DIVISION 1. EDWABDSIAE.

Solitary sea anemones, small and slender, usually imbedded in the
sand, the foot being pointed for burrowing; with 14 to 48 tentacles and

* "Report of the Actinia," etc., by J. P. McMurrich, Proc. U. S. Nat. Mus., Vol.
16, p. 119, 1893. "Synopsis of North American Invertebrates, The Actiniaria," by
G. H. Parker, Am. Nat, Vol. 34, p. 747, 1900. "The Actinians of Porto Rico,"
by J. E. Duerden, Bull. U. S. Fish. Com., Vol. 20, p. 323, 1900.

140

CCELENTEEATA

8 mesenteries (protocnemes), 2 additional pairs of rudimentary protoc-
nemes and a few small metacnemes being also present; outer surface
characterized by 8 longitudinal ridges and often incrusted with sand
and other foreign substances: 4 genera and about 20 species.

1. EDWARDSIA Quatrefages. Form slender, prismatic; tentacles 16
or less in 2 circles of 8 each, of which the outer circle is the larger;
2 siphonoglyphs : several species.

E. elegans Verrill. Number of tentacles 16; length 25 mm.: north
of Cape Cod, in shallow water.

E. leidyi Ver. Number of tentacles 16; length
30 mm.; diameter 1.5 mm.; parasitic in Mnemiopsis
leidyi : Vineyard Sound and southwards ; common.

2. EDWARDSIELLA Andres. Form cylindrical;
tentacles more than 16, usually at least 24, of which
8 are in the outer row: several species.

E. lineata Verrill. Number of tentacles 18 to 30;
length 25 to 35 mm.; diameter 3 mm.; color brown:
from Vineyard Sound southwards, in 4 to 12 fathoms;
common among worm tubes, rocks, etc.

E. sipunculoides Stimpson (Fig. 225). Tentacles
20 to 36; length 12 cm. extended; diameter 4 mm.;
color brown: Cape Cod and northwards, in shallow
water.

Fig. 225

Edwardaiella

sipunculoides

(Torrey).

DIVISION 2. CEEIANTHEAE.

Solitary sea anemones, long and slender, usually imbedded in sand
or mud, with numerous tentacles in 2 rows, an outer, marginal, and an
inner, circumoral row, and with numerous mesenteries; retractor and
sphincter muscles weak or wanting in the adult, ectodermal muscles
acting as retractors; but 1 siphonoglyph present; ectoderm with nu-
merous gland and nettle cells which discharge sufficient mucus and
nematocysts to form a long tube in which the animal lives: several
genera with about 20 species.

CERIANTHTJS Delle Chiaje. Lower end rounded and provided with
a terminal pore: 2 species on the Atlantic and 3 on the Pacific
coast.

C. americanus* Verrill. Marginal tentacles up to 125 or more;
length of body up to 60 cm. extended; diameter 25 mm.; color brown:
Cape Cod to Florida, in shallow water.

* See "The Structure of Cerianthus americanus," by J. P. McMurrich, Jour.
Morph., Vol. 4, p. 131, 1890.

ANTHOZOA

141

C. borealis* Ver. (Fig. 226). Tentacles very numerous; length of
body up to 45 cm. extended ; diameter 4 cm. : Long Island Sound to Bay
of Fundy, in 7 to 150 fathoms; very rare
south of Cape Cod.

DIVISION 3. ZOANTHEAE.

Usually colonial sea anemones springing
from an incrusting or stolon-like base; ten-
tacles numerous, in 1 or 2 rows; mesenteries
with a characteristic arrangement ; 1 siphono-
glyph present: about 8 genera and over 75
species, many of which are epizoic in habit,
being incrusted on hermit crabs, sponges,
hydroids, etc.; several genera.

1. ZOANTHUS Cuvier. Polyps claviform
or cylindrical, elongate, usually rising singly

from a network of stolons, and with no foreign bodies incrusted in their
outer surface: numerous species.

Z. sociatus (Ellis). Polyps about 17 mm. high, springing from
stolons or rarely an incrusting membrane, or from one another; tentacles
48 to 60 : West Indies.

2. EPIZOANTHUS Gray. Surface of body incrusted with sand and
other foreign bodies; colony consists of several individuals rising from

a membrane-like base which may cover a variety
of living or non-living objects.

E. americanus Verrill (Fig. 227). Tentacles
38 or more ; height of polyp 25 mm. : attached to
stones or to hermit crabs in 20 to 400 fathoms,
from New Jersey to Gulf of Saint Lawrence.

Fig. 226

Cerianthus borealis
(Kingsley).

Fig. 227

Epizoanthus americanus
(from Parker).

DIVISION 4. HEXACTINIAE.

Solitary sea anemones, often of large size,
with 6 pairs of mesenteries in the simplest forms,

and approximate multiples of 6 in the higher ones, with usually 2 siphon-
oglyphs and a large number of tentacles; the animals usually fasten
themselves temporarily to rocks, etc., by the flat foot, which acts like a
sucker, and can move slowly from place to place : about 300 species.

* "Description of Cereanthus borealis Verrill," by J. S. Kingsley, Tufts College
Studies, VoL 1, p. 345, 1904.

142 CCELENTERATA

Key to the families of Hexactiniae here described:

Oji Pedal disc absent ; usually sand dwellers 1. HALCAMPIDAE

a2 Pedal disc present.
&! Acontia absent.

Ci Body tuberculated 2. BUNODIDAE

c2 Body not tuberculated 3. PAEACTIDAE

6a Acontia present 4. SAGABTIIDAE

FAMILY 1. HALCAMPIDAE.

Pedal disc absent, the lower end being rounded or pointed and often
swollen; mesenteries few in number, 6 pairs of protocnemes with 4
to 6 pairs of metacnemes being present; no special sphincter; tentacles
12 to 36: about 6 genera.

1. HALCAMPA Gosse. Body long and slender with longitudinal
grooves and composed of 3 sections, an oral retractile portion, an inter-

Fig. 228 Fig. 229 Fig. 230

Fig. 228 — Halcampa farinacea (from Parker). Fig. 229 — Bicidium parasiticum
(from Parker). Fig. 230 — Eloactis producta (from Parker).

mediate portion usually coated with sand, and a pedal portion ; 2 siphono-
glyphs : several species, which live in sand and mud.

H. farinacea Verrill (Fig. 228). Tentacles 12 in 2 rows; body
25 mm. long extended and 3 mm. in diameter; color whitish, with
longitudinal bands of brown; disc yellow: north of Cape Cod, in 8 to
10 fathoms.

2. BICIDIUM Agassiz. Twelve tentacles in a single row; mouth with
a proboscis (conchula) : several species.

B. parasiticum Ag. (Fig. 229). Body 30 mm. long extended and
6 mm. thick : parasitic on Cyanea, fixing itself by the mouth on the manu-
brium, subumbrella, or in the gastrovascular cavity; also in the sand:
Cape Cod to Bay of Fundy.

3. ELOACTIS Andres. Body slender and very contractile; tentacles
short and blunt or capitate and in two rows : 5 species.

E. producta And. (Fig. 230). Tentacles 20; body with 20 longitu-
dinal ridges, 25 cm. long extended; diameter 18 mm.; color whitish or
salmon : South Carolina to Cape Cod, buried in the sand or on the under
side of stones in shallow water.

ANTHOZOA 143

FAMILY 2. BUNODIDAE.

Body often of large size, with a strong entodermal sphincter and
usually a tuberculated outer surface: about 10 genera.

1. BUNODES Gosse. Outer surface with longitudinal rows of tuber-
cles; tentacles rather short, retractile: 15 species.

B. Stella Verrill (Fig. 231). Body 50 mm. high; oral disc 35 mm.
wide ; tentacles 48 to 72 : north of Cape Cod, in shallow water.

2. ATJLACTINIA Verrill. Outer surface with longitudinal rows of
tubercles on upper half; lower half smooth: several species.

A. capitata Ver. Body 15 cm. high and 35 mm. in diameter; ten-
tacles 96 in 4 circles: North Carolina to Florida, in shallow water.

3. EPIACTIS Verrill. Outer surface of body with a band of egg
pits around its middle: 1 species.

E. prolifera Ver. (Fig. 232). Height 10 mm.; diameter 12 mm.;

Fig. 231 Fig. 232 Fig. 233

Fig. 231 — Bunodes stella (from Parker). Fig. 232 — Epiactis prolifera (from Parker).
Fig. 233 — Tealia crassicornis (from Parker).

tentacles about 96; egg pits as many as 30 or 40: Pacific coast from
Puget Sound to San Francisco.

4. TEALIA Gosse. Outer surface with scattered tubercles; body
short and thick and more or less covered with sand, bits of shell, etc.;
tentacles short and thick: several species.

T. crassicornis (0. F. Miiller) (Fig. 233). Height 5 cm.; diameter
12 cm.; tentacles 160; color reddish with gray tubercles: northern seas,
extending southward to Puget Sound and Cape Cod, in 14 to 40 fathoms ;
Europe.

FAMILY 3. PARACTIDAE.

Anemones with a strong sphincter and a smooth outer surface : about
10 genera.

1. PARACTIS Milne-Edwards. Body with longitudinal grooves; ten-
tacles slender, not very numerous, and all of equal length: several
species.

P. rapiformis (Lesson) (Fig. 234). Body 80 mm. high extended,
and 25 mm. in diameter; surface nearly smooth, pinkish in color; pedal

144 CCELENTEEATA

disc small ; tentacles short : buried in the sand near low water mark ; from
Cape Cod to Hatteras; Europe.

FAMILY 4. SAGAETIIDAE.

Anemones with a sphincter and with acontia ; cinclides usually present ;
tentacles usually numerous: 20 genera.

1. SAGAETIA Gosse. Outer surface smooth; oral disc not lobed;
cinclides present; tentacles in 3 or 4 cycles and retractile: many species.

S. luciae Verrill. Body 8 mm. high, 6 mm. in diameter, olive green
in color, with about 12 longitudinal orange stripes ; 84 tentacles in 4 rows :
very common on stones and shells in tide pools; Long Island Sound to
Massachusetts Bay and farther north.

S. leucolena Ver. Body elongate, 6 cm. long extended, 10 mm. in
diameter, with a translucent flesh color; tentacles 96, in 4 rows: common

Fig. 234 Fig. 235 Fig. 236

aractis rapiformis (from Parker). Fig. 235 — Sagartiam
Parker). Fig. 236 — Metridium dianthus (from Parker).

Fig. 234 — Paractis rapiformis (from Parker). Fig. 235 — Sagartia modesta (from

th

under stones and in the sand in shallow water from North Carolina to
Cape Cod.

S. modesta Ver. (Fig. 235). Height 6 cm.; diameter 15 mm.; color
yellowish; tentacles 60: buried to the tentacles in sand; Long Island and
Vineyard Sounds.

2. METRIDIUM Oken (Actinoloba Blainville). Outer surface smooth;
pedal disc broad; oral disc lobed; cinclides present; tentacles very
numerous and short: several species.

M. dianthus (Ellis) (M. marginatum Lesson) (Fig. 236). Length up
to 10 cm., width 7 cm.; color variable, but usually brownish or yellow-
ish : the largest and one of the commonest sea anemones on the Atlantic
coast; New Jersey to Labrador, from low-water mark to 90 fathoms;
Pacific coast; Europe.

3. ADAMSIA Forbes. Pedal disc adherent, the animals fixing them-
selves to the shells of hermit crabs or to crustaceans ; a band of cinclidial
tubercles around the base of the column, the rest of which is smooth.

A. tricolor Lesson. Height 75 mm. ; diameter 45 mm. ; tentacles 500
or more in large individuals: on hermit crabs; North Carolina to Florida,
in shallow water.

ANTHOZOA

145

SUBORDER 3. MADREPORARIA.*

The stony corals. The polyps are either solitary or colonial, and
secrete from the ectoderm a very hard, calcareous skeleton (Fig. 237).
This usually takes the form in each case of a cup into which the polyp
or zooid can retract itself and which consists essentially of a system of
radial vertical plates or septa projecting into the interior of the polyp,
but always covered with the three layers of the body wall and alternating,
in a general way, with the mesenteries (Fig. 238). The outer edges of
these stony septa usually join an outer wall called the theca, which is
the outer part of the cup in which the polyp sits. In the middle of the
cup is often a central column (columella). As the polyps grow, they
constantly build up the theca and the septa, withdrawing from the

Fig. 237

Fig. 237 — Diagram of a coral colony (Boas). 1, extended coral polyp; 2, retracted
coral polyp ; 3, longitudinal section of a coral polyp ; 4, calcareous cup from which the
polyp has been removed ; 5, columella ; 6, septa ; 7, theca ; 8, tabulae. Fig. 238 —
Cross section of a coral, the stony skeletons being black (Boas). 1, septum ; 2, mesen-
tery ; 3, theca.

deeper portions, which may become cut off by horizontal partitions —
the tabulae. The colonies increase in size by growth and budding of
the polyps, producing, in this way, the coral reefs which are such an
important feature of tropical seas. All the reef-forming corals live in
shallow water, 300 feet being the maximum depth in which they are
found.

The suborder contains over 1,000 species, grouped in 3 divisions.
Most of the species are found in tropical or subtropical waters, a few,
however, occurring in temperate and even in Arctic seas.

Key to the divisions of Madreporaria:

av Coral porous ; septa not more than 12 1. PEEFOBATA

a2 Coral solid ; septa usually numerous.

&! Septa without cross bars 2. APOROSA

62 Septa with cross bars 3. FUNGACEA

* See "The Florida Reefs," by L. F. Pourtales, Bull. Comp. Zool., Vol. 6, p. 102,
1880. "The Tortugas and Florida Reefs," by A. Agassiz, Mem. Am. Acad., Vol. 2,
1882. "The Stony Corals of the Porto Rican Waters," by T. W. Vaughan, Bull.
TJ. S. Fish. Com., Vol. 20, Pt. 2, p. 291, 1900,

146

C(ELENTERATA

'>. -w -;•.
;.'.:.£*

Fig. 239 — Cups of Porites

showing septa

(Vaughan).

DIVISION 1. PERFOEATA.

Corals wholly or partly porous or reticulate; zooids small with not
more than 12 septa (Fig. 239), which are sometimes indistinct: 2

families, which include many important
reef-building corals.

FAMILY 1. ACEOPOEIDAE.

Colony usually branched, the coral
being porous and containing canals con-
necting the polyps, which are usually small
and crowded ; mesenteries in bilateral pairs ;
cup small, deep, without columella and with
6 or 12 septa: about 8 genera and over 150
species.

ACROPORA L. (Madrepora L.). Colony
branched, being either flabellate, radiate or
thick and little branched except towards the periphery; zooids project-
ing; terminal polyps with 6, lateral polyps with 12 tentacles; color
usually due to symbiotic algae: many species, in most tropical seas; 1
species in the West Indies.

A. muricata L. Colony large (1 m. by 50 cm.), and usually spread-
ing, with 3 common varieties; A. cervicornis Lamarck, which is loosely
branched, A. prolifera Lam. (Fig. 240), in which
the branches are more crowded and often fused
together, and A. palmata Lam., made up of large
fan-shaped masses: West Indies and Florida.

FAMILY 2. PORITIDAE.

Colony with a variety of forms, usually in-
crusting and massive, often forming thick
branches, but rarely dendritic; zooids small and
close together; coral porous and made up of a
system of trabeculae and cross bars: about 12
genera and 100 species, many of which are reef-
building.

PORITES* Lamarck. Cup with about 12
short septa; columella present but often indistinct
West Indian; often forming very large colonies.

P. porites (Pallas). Colony more or less branching, there being
3 well-marked varieties; P. clavaria Lam., consisting of very thick

* See "On the Genus Porites," by R. Rathbun, Proc. U. S. Nat. Mus., Vol. 10,
p. 854, 1887,

Fig. 240

Acropora muricata
(Vaughan).

many species, 2

ANTHOZOA

147

upright branches; P. furcata Lam. (Fig. 241), in which the branches
are slender, and P. divaricata Lesueur, in which the branches are quite

Fig. 241

Fig. 242

Fig. 241—Porites porites (Vaughan). Fig. 242— OcuWna
diffusa (Vaughan). A, the entire colony ; B, a single
cup, showing the septa.

slender (6 mm. in diameter, or less) and spreading: West Indies and
Florida.

P. astreoides Lam. Colony not branching, but more or less globose,
often with thick lobes: West Indies and Florida.

DIVISION 2. APOROSA.

Coral solid; cup with usually numerous septa (Fig. 242, B) : about 10
families.

Key to the families of Aporosa here described:

Oj Mostly solitary corals 1. TUBBINOLIIDAE

0, Colonial corals.

6t Zooids not contiguous 2. OCULINIDAE

&2 Zooids close together or confluent 3. ASTEEIDAE

FAMILY 1. TUBBINOLIIDAE.

Mostly solitary corals, with numerous septa and without a true
theca, imbedded in the sand or attached to some object : about 50 genera
and several hundred species, of which the greater number are fossil.

FLABELLTIM Lesson. Coral solitary, flattened more or less, tapering
towards the base, which is attached in youth but may become detached
later: over 50 species.

F. goodei Verrill. Height up to 80 mm.; greater diameter 12 cm.,
lesser 43 mm.; color in life salmon with brown stripes; a very fragile
coral : Newfoundland to Florida, in 200 to 500 fathoms.

FAMILY 2. OCULINIDAE.

Colony usually dendritic, with large zooids more or less widely sep-
arated from one another; coral compact with 12 to 48 distinct septa and
usually a columella: about 22 genera.

OCULINA Lamarck. Colony dendritic with spirally arranged zooids:
many species.

148

CCELENTEEATA

O. diffusa Lam. (Fig. 242). Colony very much branched, the
branches forming an angle of about 30°; cups 3 mm. in diameter: North
Carolina to Florida, often common in shallow water.

FAMILY 3. ASTR^IDAE.

Usually colonial corals with the zooids so crowded that there is
little or no space between them, and in some cases being confluent;
colony compact and massive or erect; a few species are solitary: hun-
dreds of genera and species, be-
ing the largest family of corals.
1. ASTRANGIA Edwards and
Haime. Colony incrusting, the
zooids being distinct and more
or less isolated, with 6 septa of
the 1st cycle, 6 smaller ones of
the 2nd, and incomplete 3rd and
4th cycles: 4 American species.
A. danae Agassiz (Fig. 243). Colony small, containing from 5 to
30 individuals, incrusted on stones, shells, etc., up to 10 cm. in diameter
and 5 cm. high: Florida to Cape Cod, in shallow water; common.

2. ORBICELLA Dana. Colony usually massive with zooids distinct
and separated by deep concave spaces: numerous species.

Fig. 243 — Astrangia d<mae (from Davenport),

Fig. 245

Fig. 244 — Orblcella annularis (Vaughan).
Fig. 244 ^^g^ Fig. 245— Meandrina meandrites (Vaughan).

O. annularis (Lamarck) (Fig. 244). Colony globose; cups 2 mm.
in diameter with 12 septa of the first and 12 of the second order : Florida
and the West Indies.

3. MEANDRINA Lamarck. Zooids confluent; tentacles, mesenteries,
and septa arranged in rows ; the mouths of the polyps distinct : numerous
species.

M. meandrites (L.) (Fig. 245). Colony 4 to 8 cm. or more long
and half as broad with a single large main groove and large septa;
columella present: West Indies and Florida.

ANTHOZOA

149

M. sinuosa Lesueur (Platygyra viridis Les.) (Fig. 246). Brain-
coral. Colony incrusting and massive, 25 cm. in diameter or more;
surface made
up of numerous
sinuous ridges,
which are the
septa, and
grooves: West
Indies and
Florida.

DIVISION 3.
rUNGACEA.

Solitary or
colonial corals
in which the
septa are join-
ed by cross
bars or synap-
ticula: 5 fami-
lies.

Fig. 246 — M eandrina sinuosa (Vaughan).

FAMILY 1. PLESIOFUNGIIDAE.

Coral solitary or colonial, with additional ridges (dissepiments)
on the inner wall of the cup between the septa : about 15 genera.

SlDERASTRE A*

Blainville. Colony with
distinct zooids, crowded
and more or less polyg-
onal, and forming
rounded, unbranched
masses.

S. radians (Pal-
las). Cups about 3 mm.
by 2 mm., rounded, with
the fourth cycle of septa
incomplete : West Indies.

S. siderea (Ellis
and Solander) (Fig.

Fig. 247 — Siderastrea siderea (Vaughan),

247). Cups about 5 mm. by 4.5 mm., subhexagonal, with 4 complete cycle
of septa: West Indies.

* See "The Coral Siderastraea," by J. E. Duerden, Pub. Cam. Inst, No. 20, 1904.

150 CTENOPHOEA

FAMILY 2. FUNGIIDAE. (MUSHROOM CORAL.)

Coral solitary or colonial, often of large size, flat and disc-like in shape
with numerous septa; the living disc covers the septa and from its surface
rise very numerous tentacles ; the embryo gives rise to a conical coral called
a trophozooid, the upper part of which expands, breaks off, and becomes
the adult coral, a process which may repeat itself a number of times:
about 12 genera.

FUNGIA Dana. Coral solitary and of large size, convex on the
upper and concave on the lower side; without siphonoglyph : numerous
species, 1 American.

F. elegans Verrill. Coral round and thick, about 6 cm. in diameter:
Gulf of California.

SUBPHYLUM 3. CTENOPHOEA.*

Very soft and delicate jellyfishes which live mostly in the surface
waters of the sea. The body is usually more or less spherical, pear-shaped
or cylindrical in shape, and is both radially and bilaterally symmetrical.
Its outer surface is without hard skeletal structures and bears eight
longitudinal bands of cilia, which are the characteristic "combs"
(Fig. 249) and the organs of locomotion. Each of these bands is com-
posed of a series of transverse plates formed by the fusion of long cilia.
The animal has an oral and an aboral end which are opposite each other.
At the former is the mouth, an elongated slit which leads into a deep
flattened cavity lined with ectoderm, called the stomach. It is into this
space that the food is taken and digested. At the aboral end of the
body is a slight cavity which is connected with the eight bands of cilia
by four ciliated grooves, and in which are calcareous concretions and
sensory cells. The sense organ thus formed is called the statocyst and
is an organ of equilibration.

Many ctenophores have a pair of long retractile tentacles which
project from a pair of deep pockets in opposite sides of the body (Fig.
249). These tentacles have short branches or pinnae and their ectoderm
is provided with numerous peculiar adhesive cells which aid in cap-
turing and killing the prey; they are very retractile, and can be wholly
or partially withdrawn into the pockets. Other tentacles and projec-
tions are also present in certain species.

* See "Ctenophorae," by L. Agassiz, Contributions to the Natural History of
the United States, Vol. 3, p. 155, 1860. "Die Ctenophoren des Golfes v. Neapel,"
by C. Chun, Fauna u. Flora d. Golfes v. Neapel, Vol. 4, 1880. "The Ctenophores of the
San Diego Region," by H. B. Torrey, Univ. of Cal. Pub., Vol. 2, p. 45, 1904. "Cteno-
phores of the Atlantic Coast of North America," by A. G. Mayer, 1911.

TENTACULATA

151

It will be seen that a longitudinal plane passed through the body
which includes the mouth and stomach divides the body into two sym-
metrical halves; a transverse plane, on the other hand, reveals a radial
type of structure.

The gastrovascular space consists of a complex system of narrow
tubes (Fig. 248) lined with entoderm which join the inner end of the
stomach, and communicate with the outside also
by means of either one or two pores at the aboral
end of the body. Eight of these tubes which lie
immediately beneath the eight longitudinal bands
of cilia form the most important part of the sys-
tem. The space between these gastrovascular tubes
and the outer ectoderm is filled with the soft jelly-
like mesenchyne which differs from the mesoglea
of the other ccelenterates in that it arises as the
result of the proliferation of definite cells during
the early development of the animal; in it are
nuclei and muscle fibers.

All ctenophores are hermaphroditic, the gonads
consisting of a pair of bands, one male and the
other female, which lie side by side against the
outer wall of the main longitudinal canals of the
gastrovascular space, the genital products reaching

the outer sea water through the mouth. The young animal passes
through a complex metamorphosis before reaching the adult condition;
but there is no alternation of generations. Certain genera may exhibit
pa?dogenesis, reproducing in the larval stage, and again as adults.

Ctenophores are common marine animals, often occurring in enor-
mous schools. They are noted for their delicacy and beauty, the rapidly
vibrating combs refracting the light and showing a rapid play of
changing colors. They are also often highly phosphorescent at night.
Their food consists of crustaceans, fishes, and other small animals, often
including their own kind. The subphylum contains two classes and less
than 100 species, 21 of which occur off the Atlantic coast.

Key to the classes of Ctenophora:

Ot Either tentacles or oral lobes present 1. TENTACULATA

o, Tentacles and oral lobes absent 2. NUDA

Fig. 248 — Diagram
of a ctenophore, show-
ing the canal system
(Mayer). 1, aboral end
with statocyst ; 2, lon-
gitudinal canals ; 3,
oral end of body ; 4,
mouth; 5, stomach.

CLASS 1. TENTACULATA.

A pair of long tentacles present, in certain cases in the larval stage
only, oral lobes being then present in the adult: 3 orders.

152

CTENOPHORA

Key to the orders of Tentaculata:

di Body more or less globose or cylindrical.

&! Long tentacles present 1. CYDIPPIDA

&2 No tentacles in adult animal ; oral lobes present 2. LOBATA

o2 Body compressed and ribbon-like 3. CESTIDA

ORDER 1. CYDIPPIDA.

Body spherical or cylindrical or compressed in the plane transverse
to the tentacular axis; tentacles very long, on opposite sides of the
body, springing each from a deep pocket: several families.

FAMILY PLEUKOBKACHIIDAE.

Body spherical or ovoid, with the 8 ribs of equal
length: 4 genera.

1. PLEUROBRACHIA Fleming. Body but very little
compressed; combs rather long but not reaching the oral
or aboral areas: about 8 species.

P. pileus (Fabricius) (P. rJiododactyla Agassiz; P.
bachei A. Agassiz) (Fig. 249). Body about 20 mm. long
and 18 mm. wide, and very transparent; tentacles about
15 cm. long and white or rose-colored, with long pinnae :
from the south side of Long Island to Greenland ; breeds
in August and September; Europe; Pacific coast.

P. brunnea Mayer. Body 12 mm. long, ovoid ; stom-
ach of an opaque yellowish-brown color; each tentacle
with a knob-shaped end: coast of New Jersey; rare.

2. MERTENSIA Lesson. Body much compressed, the
tentacular axis being the wider; the 4 subtentacular

combs longer than the 4 subventral ones: 1 American species.

M. ovum (Fabricius). Body about 5 cm. long and ovoid in outline;
tentacles, combs, and sense organ light pink in color: Arctic Ocean to
New Jersey; rare south of Cape Cod.

ORDER 2. LOBATA.

Body ovate, compressed in the plane transverse to that of the stom-
ach; mouth wide, with a large and prominent oral lobe on each side of
it; at the base of each lobe is a pair of long projections called auricles;
tentacles of the ordinary kind wanting in the adultj but numerous, deli-
cate, filamentous tentacles may fringe the margin of the mouth and
the auricles; aboral sense organs sunk in a pit; a larval cydippiform
stage present, which has a pair of tentacles issuing from pockets and
in certain genera may have sexual reproduction: several families.

Fig. 249

Pleurolrachia

pileus
(Mayer).
T, tentacles ;
C, combs ;
other refer-
ences as in
Fig. 248.

TENTACULATA

153

Fig. 250 — Bolinopsis in-
fundibulum (Mayer).

auricle ;
mouth.

2, oral lobe ;

FAMILY 1. BOLINOPSIDAE.

Oral lobes of medium size; auricles short: 3 genera.

BOLINOPSIS Agassiz (Bolina Mertens). With the characteristics of
the family; combs not prolonged onto the oral
lobes : 6 genera.

B. infundibulum (0. F. Miiller) (B. alata
Ag.) (Fig. 250). Body up to 15 cm. long, of
a transparent bluish-white color: from Vine-
yard Sound to Labrador, often very common
north of Cape Cod.

FAMILY 2. MNEMIIDAE.

Lobes large, each bounded on each side
by a deep lateral furrow which extends to the
aboral end of the body; auricles long and
slender: 4 genera.

MNEMIOPSIS Agassiz. Auricles long and
large ; combs prolonged onto the lobes almost to
their oral ends: 3 species.

M. leidyi A. Agassiz (Fig. 251). Body up to 10 cm. long and very
transparent, at night very phosphorescent: Long Island and Vineyard
Sounds and south to the Carolinas, often in large
swarms; often parasitized by a sea anemone,
Edwardsia leidyi.

M. garden! Ag. Length 4 cm.; lobes rather
small and covered with warts; body translucent or
bluish in color: Chesapeake Bay to Florida;
abundant.

ORDER 3. CESTIDA.

Body flattened in the plane of the tentacles
and so enormously extended in the plane of the
stomach that it has the shape of a ribbon which
may be a meter or more long by 8 cm. high ; 4 of
the combs (the subtentacular) are very short, the
other 4 are very long; tentacles more or less rudi-
mentary, tentacle sheaths deep : 2 genera.
With the characters of the order: 2 species.

C. veneris Les. Venus' girdle. Body transparent, shimmering with
violet, blue, or green : tropical seas, occasionally brought to our shores by
the Gulf Stream, fragments of the animal being occasionally seen on the
New England coast. .

Fig. 251 — Mnemiopsis
leidyi (Mayer). 1, au-
ricle ; 2, oral lobe ; 3,
mouth.

CESTUS Lesueur.

154

CTENOPHORA

CLASS 2. NUDA.
Tentacles absent: 1 family. ,
FAMILY BEEOIDAE.

Body conical or ovate and compressed, with a mouth and stomach so
very wide that the body is much the shape of a compressed thimble ; combs

extend the length of the body; a network
of canals throughout the body which
ramify off from the gastrovascular canals :
2 genera with few species; they are cos-
mopolitan, often occurring in large
swarms, and are noted for their voracity,
sometimes swallowing other ctenophores
larger than themselves.

BEROE Browne (Idyia Freminville) .
Body more or less conical or ovoid : about
14 species.

B. ovata Chamisso and Eysenhardt
Body often tapering from the mouth to
the aboral pole and much compressed, 10
cm. long, pink in color towards the north,
milky white towards the south: Chesa-
peake Bay to Florida; cosmopolitan;
abundant.

B. cucumis Fabricius (B. roseola
Agassiz) (Fig. 252). Body 10 cm. long,
9 cm. wide and 6 cm. thick and rose color: Vineyard Sound to Labrador,
often very plentiful towards the north.

Fig. 252 — Beroe cucumis (Mayer).

PHYLUM III.

VERMES. (THE LOWER WORMS.*)

Worms of primitive structure and often of small size, usually without
paired locomotory appendages or a distinct head, and with non-metameric
and often permanently ciliated bodies. The animals are usually sluggish
of movement and in very many cases either sessile or parasitic.

The Vermes form a polymorphic group of animals, the eight subphyla
of which do not necessarily bear a close genetic relationship to one another.
They, however, have many structural features in common and many of
the classes bear a definite relation to the trochophore larva which justifies
the placing of them in a common group., This would rank immediately
beneath the annelids and the other groups in which the trochophore
represents an ancestral form.

The class Vermes, as formed by Linnaeus, included all invertebrate
animals except arthropods. Lamarck divided the invertebrates into several
classes, of which one was Vermes, including in it both the unsegmented
and segmented worms. This arrangement, although it has been followed
by Claus, Hertwig, and other modern authors, is not now usually adopted,
and the Vermes, when used as the name of a phylum, generally include
the lower worms alone.

The phylum contains 8 subphyla.

Key to the subphyla of Vermes :

«! Animals mostly non-burrowing.
Z>! Animals mostly locomotory.
Cj Animals mostly not minute and very often parasitic.

d: Flattened worms ; very many parasitic 1. PLATHELMINTHES

d2 Round and thread-like worms; often parasitic 2. NEMATHELMINTHES

C2 Animals minute and aquatic.
di Crown of cilia at forward end ; animals mostly in fresh water.

3. TEOCHELMINTHES

d2 No external cilia ; animals marine 7. CH^ETOGNATHA

Z>2 Animals sessile.

<?! Animals colonial 4. BBYOZOA

c. Animals not colonial.

di Animals with a two-valved shell 5. BEACHIOPODA

d2 Animals form tubes 6. PHORONIDEA

ca Marine worms which burrow in the sand and mud 8. SIPUNCULOIDEA

* See "Vermes," by H. Pagenstecher and M. Braun, Bronn's Klassen und
Ordnungen des Thierreichs, Band 4, 1893. "Textbook of the Embryology of Inverte-
brates, Part I," by E. Korschelt and K. Heider, translated by E. L. Mark and W. M.

155

156 PLATHELMINTHES

SUBPHYLUM 1. PLATHELMINTHES.

Flatworms. Flattened or in some cases cylindrical worms of soft
texture which are found in the water or in moist earth, or which live as
parasites in animals or plants. The body is without a distinct head or
paired appendages and is not metamerically segmented. A body cavity is
also wanting in most of them, the spaces between the internal organs being
secondarily filled with a vesicular connective tissue, called parenchyma.
The outer surface of the body is either a ciliated epithelium or a thick
unciliated cuticula and no hard skeletal structures are present except
chitinous hooks and spines. The mouth is usually in the ventral surface
in the Turbellaria and at the front end of the body in the other groups,
and an anus is not present, except in the Nemertea. A mouth and an
alimentary tract are wanting in the tapeworms. The nervous system
consists of paired cerebral ganglia forming a brain at the forward end
and nerves extending to various parts of the body. Special sense organs,
when present, consist of simple eyes, tentacles, or statocysts. The excretory
system consists of slender tubes extending throughout the parenchyma,
the final branches of which end in flame cells. It opens to the outside
either through a single pore or through several paired pores. No special
respiratory organs are present, and except in the Nemertea, no circulatory
organs or blood fluid. The reproductive organs 'are complex, except
among the Nemertea, hermaphroditism being general. Asexual reproduc-
tion by budding or fission is common in certain groups.

History. — Certain of the parasitic flatworms have been known from
time immemorial. Linnaeus included all invertebrates except arthropods
(his Insecta) in the class Vermes, one of the orders of which was the
Intestina, or worms proper. Cuvier (1798) first called attention to the
fundamental distinction between the unsegmented and the segmented
worms, to the former of which Rudolphi (1808) gave the name Entozoa,
most of the unsegmented worms as then known being parasites. It was
this author who, following however Zeder in his general classifications,
laid the foundation of our present classification of parasitic worms, of
which he formed five orders, the roundworms or Nematodes, the Acan-
ihoceplnala, the Trematodes, the tapeworms or Cestodes, and the bladder-
worms or Cystiri. F. S. Leuckart and von Baer showed that these groups
did not necessarily bear a genetic relationship to one another. Vogt in
1851 first joined the four orders of flatworms to form a class which he

Woodworth, 1895. "Flatworms and Mesozoa, Nemertines, Thread-Worms and Sa-
gitta, Rotifers," eta, Cambridge Natural History, Vol. 2, 1896. "Les Ver-
midiens," by Delage et He>ouard, Traite" de Zool. Concrete, Vol. 5, 1897. "A
Student's Textbook of Zoology," Vol. 1, by Adam Sedgwick, 1898. "A Treatise on
Zoology, Part 4," edited by E. Ray Lankester, 1901.

TUEBELLAEIA 157

called Platelmia, while of the three orders of roundworms he formed the
class Nematelmia, an arrangement which is still maintained.

The subphylum contains 4 classes.

Key to the classes of Plathelminthes :

G! No anus ; no blood vessels ; animals mostly hermaphroditic, with very

complex genital organs.
&! Animals with rare exceptions free-living ; body ciliated externally.

1. TURBELLABIA

62 Animals parasitic ; not ciliated externally ; mouth when present at for-
ward end (with some rare exceptions).
Ci Intestine and mouth present ; animals small and unsegmented.

2. TEEMATODES
c, Intestine and mouth absent; animals usually long and segmented.

3. CESTODES
oa Anus, anterior proboscis, and blood vessels present; animals mostly

unisexual and free-living, usually long and bandlike 4. NEMEETEA

CLASS 1. TURBELLARIA *

Soft, free-living flatworms, mostly under an inch in length, which are
found either in the water creeping slowly over stones or plants or living
in moist places on the land. The body is flat in shape and usually elon-
gate, but in some cases nearly circular. The external surface is ciliated
and from it is exuded the slimy secretion of numerous glands, in which
are often contained minute rod-like bodies called rhabdites which are pro-
duced in certain glandular cells either of the integument or of the paren-
chyma. A few turbellarians possess functional nettle cells which, however,
they have acquired from hydrozoans they have eaten, and a few have
adhesive papillae or suckers.

No body cavity is present, the spaces between the organs being filled
with the parenchyma. The mouth (Fig. 263) is usually near the middle of
the ventral surface but may in the different species vary in position from
the forward to the hinder end. It opens into a muscular pharynx which
is usually of large size and one of the most prominent organs in the body :
it can usually be thrust out of the mouth so as to form a proboscis by
means of which the animal takes and often digests its food. An intestine
is not present in the Accela: in the other turbellarians it is either a tubular
or a branched structure. An anus is not present, fecal matter being dis-
charged through the mouth: in certain cases, however, the intestinal

* See "Rep. Invert. Vine. Sd.," by A. E. Verrill, Rep. U. S. Com. Fish, for 1871
and 1872. "Beob. tiber die Siisswasser Turbel. Nordam.," by W. A. Silliman, Zeit.
f. wiss. Zool., Vol. 41, p. 48, 1885. "Turbellaria," by L. von Graff, Bronn's Kl. u.
Ord., Vol. 4, Abt. 1, Accela und Rhabdocoelida, 1904-08. "Turbellaria," by same.
"Die Susswasserfauna Deutschlands," 1909. "Vergleichung der Nordamerikanischen
und Europaischen Turbellarienfauna," by same, Proc. Sev. Int. Zool. Cong., 1910.
"Acoela, Rhabdocoela, und Alloeocoela des Ostens der Vereinigten Staaten," &c., by
same, Zeit. f. wiss. Zool., Vol. 99, p. 321, 1911.

158 PLATHELMINTHES

branches open to the outside. The excretory system consists of a median
canal or one to four pairs of longitudinal canals which open to the
outside through usually paired pores and numerous small canals which
penetrate the parenchyma in all directions and end in flame cells. The
nervous system consists of a pair of ventral nerve cords, the anterior
ends of which are enlarged to form a brain and which are joined by
numerous transverse commissures. From the brain nerves go to the eyes
and tentacles, when these organs are present, and also to the sensitive
anterior end of the body.

The reproductive organs are very complex, the animals being with
rare exceptions hermaphroditic, and differ somewhat in the various groups.
The genital opening, which is either single or double, is in the ventral
surface back of the mouth. Most species lay their eggs in capsules
which are attached to plants or stones. A few reproduce also asexually,
by transverse fission.

Habits and Distribution.— Most turbellarians are aquatic animals,
living either in fresh or in salt water; only the Terricola are terrestrial.
The largest aquatic form (Leptoplana gigas) may be 15 cm. in length,
while the largest land turbellarians (Bipaliidae) may be 45 cm. long; the
smallest forms are of microscopic size. They are with few exceptions
carnivorous animals, living on small animals of all sorts: a few are
parasitic.

History.— 0. F. Miiller in 1776 first separated the turbellarians and
nemerteans from the other flatworms and placed them in the genus Pla-
naria. Ehrenberg in 1831 named the group Turbellaria. In 1851 Vogt
placed it with the other flatworms in the class Platelmia. The present
arrangement of the group is due principally to von Graff and Lang.
About 1,100 species of turbellarians are known, grouped in 2 subclasses.

Key to the subclasses of Turbellaria:

QI Minute marine forms without intestine 1. ACCELA

o2 Intestine present 2. CGELATA

SUBCLASS 1. ACCELA.*

Small, delicate marine turbellarians which are found free-swimming
and also among the rocks and seaweed along the shore. They are often
brightly colored, and in one genus at least (Convoluta) the pigment is
due to a symbiotic alga. No intestine is present, the food, which consists
of minute animals and plants, being introduced directly into the paren-
chyma. The mouth is often near the front end of the body, a proboscis
being often absent. Eyes are usually absent, but a statocyst lies over the
brain. The reproductive system is simple in structure, in many species

* See "Turbellaria, I. Acoela," by L. von Graff, Das Tierreich, 1905.

TURBELLARIA

159

no vasa dcferentia or oviducts being present. The subclass contains 2
families and about 40 species, of which 6 have been found in America.
Key to the families of Acoela:

0,1 One genital pore present ................................. 1. PBOPOBIDAE

o2 Two genital pores present .............................. 2. CONVOLUTIDAE

FAMILY 1. PEOPOEIDAE.

But one genital pore present; position of mouth various: 5 genera
and 14 species.

1. CHILDIA von Graff. Mouth in ventral surface behind the middle;
pharynx absent ; bursa semi-

nalis absent; 2 male copu-
latory organs, each with a
chitinous stilet : 1 species.

C. spinosa v. Gr. (Fig.
253). Length 1.4 mm.;
color light yellow: Woods
Hole.

2. ANAPERTTS von Gr.
Body elongate; bursa sem-
inalis and pharynx absent:
1 species.

A. gardineri v. Gr.
(Fig. 254). Length up to
6 mm. ; width 1 mm. ; color
red, but yellow at the two
ends: Woods Hole, with
Potychcerus caudatus, which
it resembles, but is much
less numerous than it;
movements rapid.

Fig. 254

Fig. 253 — Childia spinosa (von Graff). 1, stato-
cyst ; 2, ovary ; 3, mouth ; 4, penis ; 5, genital pore.
Fig. 254 — Anaperus gardineri (von Graff). 1, stato-
cyst ; 2, mouth ; 3, ovary ; 4, genital pore.

FAMILY 2. CONVOLUTIDAE.

Two genital pores present, the female pore being in front of the
male; bursa seminalis present; mouth near the middle of the body: 5
genera and 25 species.

1. APHANOSTOMA CErsted. Body cylindrical or flattened beneath
and narrowed behind; mouth near the middle; statocyst present; eyes
absent: 2 species.

A. diversicolor CErst. (Fig. 255). Body very variable in shape,
elliptical, with yellow at forward end; middle usually violet; length
1 mm. ; width .25 mm. : Newport, R. I., and Woods Hole, among algae in
shallow water, common; Europe,

160

PLATHELMINTHES

2. POLYCH<ERTJS Mark. Body broad and flat with either one or sev-
eral caudal filaments: 1 species.

P. caudatus Mark (Fig. 256).
Body with parallel sides and a deep
notch in the hinder margin, from which
1 to 3 caudal filaments arise; color red;
length 4 mm. ; width 1.5 mm. : on stones
along the beach from Casco Bay to
Long Island Sound; often abundant;
movements sluggish.

SUBCLASS 2. CCELATA.

Turbellarians with intestine: 3
orders.

Key to the orders of Ccdata :

«! Small forms with a straight intes-
tine 1. RHABDOCOZLIDA

a2 Usually larger forms with branched

intestine.
&! Intestine with 3 main branches.

2. TBICLADIDA
&2 Intestine with many large branches.

3. POLTCLADIDA

Fig. 255 Fig. 256

Fig. 255 — ApJianostoma diversicolor
(von Graff). 1, statocyst ; 2, female
genital pore; 3, bursa seminalis; 4,
male genital pore. Fig. 256 — Poly-
chosrus caudatus (Mark). 1, testis;
2, mouth ; 3, ovary ; 4, female genital
pore ; 5, male genital pore.

ORDER 1. RHABDOCCELIDA. (FiG. 257.)

Marine, fresh-water, and land turbellarians of small
size in which the intestine is a straight and unbranched
or at the most only slightly lobed tube or sac; yolk
glands present or not; either 1 or 2 genital pores pres-
ent: 23 families, grouped in 2 suborders with over 350
species, of which about 75 have been found in this
country; about half the species marine.

Key to the suborders of Rhabdoccelida:

Oi Intestine a straight tube 1. RHABDOCCELA

oa Intestine sac-shaped with irregular sides. .2. ALIXEOCOZLA

Fig. 257— Dia-
gram cf a rhab-
doccelid (Dalyel-
lia) (von Graff).
1, mouth; 2,
brain ; 3, intes-
tine; 4, yolk

SUBORDER 1. RHABDOCGELA.*

Body cylindrical, fusiform, filiform, or lamellate in
shape; intestine a tube or sac, usually with straight
sides; usually 2 eyes and occasionally sense pits and gland ».Ate~s^J|:
statocysts present; either a single median or a pair of 7» ovary,
excretory canals present; many forms reproduce asexually, by terminal
budding: 16 families and 275 species, 48 American.

* See "Monographic d. Turbellarien, I. Rhabdoccelida," by L. von Graff, 1882,

TURBELLARIA 161

Key to the families of Rhabdocosla here described:

j Forward end not in form of a proboscis, or where a proboscis is present
it cannot be retracted into a sheath.

&! Ovary and yolk glands not distinct.

cx Single median excretory trunk present 1. CATENULIDAE

ca A pair of excretory trunks present 2. MICROSTOMIDAE

62 Ovary and yolk glands distinct from each other.

Cj Pharynx sac-shaped and parallel to ventral surface 3. DALYELLIIDAE

ca Pharynx rosette-shaped and perpendicular to ventral surface.

4. TYPHLOPLANIDAE

j Forward end in form of a proboscis which can be retracted into a sheath.

&! One genital pore present 5. POLYCYSTIDIDAE

63 Two genital pores present 6. GYRATRICIDAE

FAMILY 1. CATENULIDAE.

Mouth in ventral surface near forward end; no preoral branch of
intestine; pharynx simple; excretory pore at hinder end, with a single
median excretory trunk; testis and ovary median and single, the former
in front of the latter; pigment eyes wanting; reproduction asexual as
well as sexual, chains of individuals forming: 5 genera and about 25
species, 14 American.

1. STENOSTOMUM* Schmidt. Body colorless; intestine often colored
brown, reaching almost to the hinder end of the body; a pair of ciliated
sense pits in front of brain and 1 to 2 pairs of light-refracting organs
behind it: 16 species, 5 American, all but

one in fresh water.

S. leucops (Duges). Chain consisting
of 8 or less individuals up to 4 mm. long;
light-refracting organs concave and 2 in
number: eastern and central states; Eu-
rope; common.

S. grande Child (Fig. 258). Chain
consisting of 4 to 6 individuals 2 to 2.6
mm. long; color orange yellow: in fresh
and brackish water; common. (vof ' 0?"^° end

2. RHYNCHOSCOLEX Leidy. Forward S^end!'1186 pits (s) ; B' P°S"
end of cylindrical body elongated into

proboscis-like appendage at the base of which are the mouth and a pair
of sense pits: 2 species.

R. simplex Leidy. Body yellowish white, 5 mm. long: Philadelphia,
at the bottom of clear brooks.

* See "Studies on Regeneration, Fission, and Regulation of Steuostoma," by
C. M. Child, Arch. f. Entwick., Vol. 15, p. 187, 1902.

162

PLATEELMINTHES

FAMILY 2. MICEOSTOMIDAE.

Mouth in ventral surface near forward end ; pharynx simple ; a pair
of excretory tubes present; sense pits and usually pigmented eyes pres-
ent: 35 species, 6 American.

1. MICROSTOMTTM Schmidt. Preoral branch to intestine present;
forward end of body not proboscis-like; hinder end tapering; chains of
individuals formed: 15 species, in both fresh and salt water.

M. lineare (0. F. Miiller). Body 1.8 mm. long; chain consisting of
18 individuals 7 mm. long; color yellowish or pink; 2 red eyes present;
nettle cells present which have been derived from ingested
hydras; hinder end with a tail on which are adhesive
papillae : eastern states ; Europe.

M. davenport! von Graff (Fig. 259). Chain consisting
of 4 individuals 1.5 mm. long; hinder end with numerous
papillae; body colorless; intestine yellow; eyes absent:
Long Island and Vineyard Sounds; on ulva and fucus.

Fig. 259

Microstomum

davenporti

(von Graff).

FAMILY 3. DALYELLIIDAE.

Large sac-shaped pharynx present; mouth near for-
ward end of body; single genital pore present; ovary dis-
tinct from yolk glands, which are either 1 or 2 in number
and usually unbranched ; testes paired ; pigment eyes usually
present ; penis usually with complex chitinous
parts: about 70 species, mostly in fresh
water; 17 American.

DALYELLIA Fleming (Vortex Ehren-
berg). Body rounded in front and tapering to a point
behind; body not pigmented but often colored by zoochlo-
rellae; 2 black eyes present, near which and the forward
end is the mouth; genital pore in posterior third of body:
46 species, 13 American, all in fresh water.

D. armigera (Schmidt). Length 1 mm.; penis with 2
short chitinous rods, each of which has a spinose terminal
branch: central and eastern states; common; Europe.

D. dodgei von Graff (Fig. 260). Penis with chitinous
parts of unequal size and shape forming a transverse row
fastened to a basal piece; length 1 mm.: the commonest
species; eastern states; in fresh and brackish water.

ogei

(von Graff).
1, mouth

2, pharynx

3, intestine
4, genital pore

5, egg.

FAMILY 4. TYPHLOPLANIDAE.

Pharynx rosette-shaped, springing from the ventral wall of the

intestine and perpendicular to the ventral body surface; ovary distinct

TUEBELLARIA

163

from yolk glands ; testes paired ; rhabdites usually prominent : 60 species,
all except one in fresh water, 8 American.

1. TYPHLOPLANA Ehrenberg. Excretory ducts open with the mouth
into a common space, which opens to the outside; without genital
atrium; dermal rhabdites absent; testes very small, near the pharynx;
eyes absent: 2 species.

T. viridata (Abildgaard). Body 1 mm. long, tapering at both ends,
behind to a blunt point, colorless, but usually colored green by zoochlo-
rellae; pharynx near middle of body with the genital pore behind it:
eastern states; Europe.

2. CASTRADA Schmidt. Excretory ducts open as in Typhloplana;
with genital atrium; eyes usually absent; dermal rhabdites absent: 27
species, in fresh water, 1 American.

C. hofmanni Braun. Body 1.5 mm. long, cylindrical, rounded in
front, tapering to a blunt point behind; pharynx somewhat in front of
middle of body and just in front of genital pore: eastern states; Europe;
abundant.

3. MESOSTOMA Ehrenberg. Excretory ducts open as in Typhlo-
plana; rhabdites very prominent; testes dorsal or lateral to the yolk

glands; genital pore in hinder third of body; mouth near
the middle; 2 eyes present; zoochlorellae absent: 13
species, 2 American.

M. ehrenbergi (Focke) (M. wardii Woodworth) (Fig.
261). Body flat, up to 15 mm. long and 4 mm. wide, but
usually much less, tapering to both ends; forward end
blunt, hinder end pointed: central states; Europe; vivip-
f-2 arous.

FAMILY 5. POLYCYSTIDIDAE.

Fig. 261

Mesostoma

ehrenbergi

(Woodworth).

1, mouth
2, intestine.

Two ovaries, yolk glands, and testes present; forward
end forms muscular retractile proboscis; rosette-shaped
pharynx forward of the middle of body; but 1 genital
pore: 16 species, 2 American.

PHONORHYNCHUS von Graff. Male genital canal
with a poisonous spine: 2 species.
P. helgolandicus (Metschnikoff). Length 1.7 mm.: Long Island and
Vineyard Sounds to the Arctic Ocean; Europe; common.

FAMILY 6. GYKATEICIDAE.

Ovaries, yolk glands, and a single testis present; forward end forms
a retractile proboscis; mouth with a rosette-shaped pharynx near
middle of body ; genital pores separate, in hinder part of body : 1 genus.

164

PLATHELMINTHES

GYEATRIX Ehrenberg. With the characters of the family : 2 species.

G. hermaphroditus Ehr. Body 2 mm. long and very contractile,

transparent: in fresh and salt water; eastern states; Europe; very common.

SUBORDER 2. ALLCEOCCELA.

Fresh-water and marine turbellarians in which the intestine is an
irregular sac or tube often with lateral diverticula; 1 or 2 genital pores
present; testes and ovaries consist of numerous
follicles: 7 families with about 75 species, 30
American.

FAMILY PLAGIOSTOMIDAE.

Intestine sac-shaped and without lateral diver-
ticula; pharynx variable and in forward part
of the body ; genital pore single
and in hinder third of body;
ovary and yolk glands distinct :
30 species, 10 American.

PLAGIOSTOMUM Schmidt.
Two or 4 eyes present ; pharynx
large, sac-shaped : 10 American
species; marine.

P. wilsoni von Graff (Fig.
262). Length 1.5 mm.: com-
mon at Woods Hole.

Fig. 262
Plagiostomum

wilsoni
(von Graff).

1, mouth

2, intestine

3, genital pore.

Fig. 263 — Diagram of
trie

clad (von Graff).
1, brain ; 2, ovary ; 3,
yolk gland ; 4, testis ;
5, intestine ; 6, phar-
ynx ; 7, mouth ; 8,
penis ; 9, genital pore ;
10, vagina ; 11, uterus.

ORDER 2. TRICLADIDA.

(Fio. 263.)

Marine, fresh-water, and
terrestrial turbellarians in which
the intestine is composed of 3

main trunks with many branches, one trunk extending forwards from the
pharynx, and the other two backwards ; body flattened, with sensitive lobes,
projections or tentacles and a pair of eyes 'at or near the forward end,
and in certain species a ventrally situated sucker; mouth and genital pore
in or behind the middle of the body; proboscis well developed: about 430
species and 6 families grouped in 3 suborders.
Key to the suborders of Tricladida:

a^ Aquatic triclads.

&! Fresh-water triclads ; planarians 1. PALUDICOLA

62 Marine triclads 2. MABICOLA

«2 Terrestrial triclads. — 3. TERBICOLA

TURBELLARIA

165

SUBORDER 1. PALUDICOLA.*

Planarians. Triclads with a central mouth, a single genital pore
behind it and an elongate, flattened body, which are found in fresh water
under stones and on plants, also in wet places under leaves, in mud, etc. ;
their food consists of crustaceans, snails, aquatic insects, etc., also of
dead animals, and they are themselves preyed upon by fish, insect larvae,
etc.; they possess remarkable regenerative powers and certain species
(Planaria maculata) are known to multiply by fission; the eggs are laid
in cocoons which are attached to stones and plants : 1 family and about
100 species, in fresh and often brackish water.

FAMILY PLANAKIIDAE.

With the characters of the suborder: about 6 genera.
Key to the genera of Planariidae here described :

Oj But 1 pharynx present.

6X Anterior margin rounded or angular. 1. PLANARIA

62 Anterior end truncated 2. DENDROCCELUM

a2 Many pharynges present 3. PHAGOCATA

1. PLANARIA 0. F. Miiller. Body elongate, flattened,
rounded or angular forward, usually with a pair of lateral
angular projections (auricles), and pointed behind; 2 eyes,
each in a colorless area; usually a pair of lateral, elon-
gated, and colorless sense spots near the eye: many
species, about 9 American.

P. maculata t Leidy (Fig. 264). Body thin, slightly
convex, elongate, tapering to the acute tail, 20 mm. long
or less; head end trapezoidal, wider than the body, with
an acute median and 2 lateral projections; mouth in
hinder half; dorsal surface spotted irregularly with black;
ventral surface whitish: North America; the commonest
fresh-water planarian.

Fig. 264

Planaria

maculata

(Woodworth)

p, pharynx.

* See "Contributions to the Morphology of the Turbellaria," etc., by W. M.
Woodworth, Bull. Mus. Comp. Zool., Vol. 31, p. 1, 1897. "Regeneration in Plana-
rians," by T. H. Morgan, Arch. f. Entwickelungsmech., Vol. 10, p. 58. "The Move-
ments and Reactions of Fresh Water Planarians," by R. Pearl, Q. J. M. S., Vol. 46, p.
509, 1903. "The Reactions of Planarians to Light," by H. E. Walter, Jour. Ex.
Zool., Vol. 5, p. 38, 1907. "Die Siisswasserfauna Deutschlands : Tricladida," by
L. Bohmig, 1909.

t See "The Life History and Normal Fission of Planaria maculata," by W. C.
Curtis, Proc. Bos. Soc. Nat. Hist., Vol. 30, p. 515, 1902.

166

PLATHELMINTHES

P. torva M. Schultze (Fig. 265). Body 13 mm. long or less; head
rounded in front and not wider than the body; color brown or black:
eastern and central states; Europe.

P. gonocephala Duges (Fig. 266). Body 25 mm. long or less; head

Fig. 265

Fig. 266

Fig. 267

Fig. 265 — Planaria torva (Bohmig). Fig. 266 — Planaria gonocephala (Wood worth).
Fig. 267 — Planaria lugubris (Bohmig).

as in P. maculata; body with parallel edges as far back as the genital
pore; color brown or greenish: eastern states; Europe.

P. lugubris Schmidt (Fig. 267). Body 20 mm. long or less; head
somewhat wider than body, rounded or bluntly triangular; color light
brown to black; ductus ejaculatorius receives the secretion of numerous
glands which appear on its inner surface : eastern
and central states; Europe.

P. simplissima Curtis. Body 8 mm. long or
less, black in color; head end blunt, without lat-
eral projections; pigment wanting over eyes;
testes few, 4 to 5 on a side: eastern states.

P. dortocephala Woodworth (Fig. 268). Body
elongate, 15 mm. or more long, with acute angular
front end and a pair of acute angular auricles;
color brown : Illinois ; common.

P. morgani Stevens and Boring. Body 10
mm. or more long, with a rounded or truncated
front end, colorless: eastern states.

2. DENDROCffiLUM CErsted. Body elongate
and flat with a truncated head end which bears a
large sucker and a pointed tail end; head set off
by a slight constriction from the body and with ia
pair of short, rounded, lateral projections; mouth near the middle:
several species.

D. gram Wilhelmi (formerly called D. lacteum 0. F. Muller) (Fig.
269). Body 10 to 26 mm. long and 3 mm. wide or less, milk white in color
with the dark-colored intestine showing through; ventral sucker at front
end ; 2 eyes and frequently 1 to 6 accessory eye spots present : eastern states.

v

9

I
f

Fig. 268

Fig. 269

Fig. 268

Planaria dortocephala
(Woodworth).

Fig. 269

Dendroccelum graffl
(Woodworth).

TURBELLARIA

167

3. PHAGOCATA Leidy. Body elongate and flat, with a rounded head
end and a blunt tail end; many pharynges present which lie in a com-
mon chamber and when extruded reach the exterior
through a single orifice, but which open separately into
the intestine: 1 species.

P. gracilis* (Haldeman) (Fig. 270). Body 30 mm.
long and 4.5 mm. wide or less, black in color; 1 large
pharynx present at the junction of the 3 main intestinal
trunks and about 22 additional pharynges which are
joined to the 2 lateral trunks: eastern states, often
plentiful in brackish water.

SUBORDER 2. MARICOLA.f

Marine triclads. Intestinal branches but little rami-
fied ; mouth in hinder half of body ; uterus behind genital
pore: 5 families and about 30 species, which live on
seaweed, stones, or shells, or are parasitic; 10 species on
east coast of America.

Pig 270
Phagocata

(Wo^d worth).

FAMILY 1. PEOCERODIDAE.

Body flattened, with otocyst but no sense pits; front
end more or less truncate, often with a pair of ten-
tacle-like projections ; 2 eyes, at some distance from front end : 2 genera.
PROCERODES Girard (Gunda 0. Schmidt). Body elongate, truncated
in front with projecting, tentacle-like corners: 16 species.
P. wheatlandi Girard (Fig. 271). Body elongate, 5
mm. long and 1 mm. wide, blackish in color; tentacles
whitish : coast of New England, often common under stones
and among algae in shallow water; Europe.

P. warreni (Girard). Front end more or less trun-
cate; body elongate, yellowish or brownish in color, 4 to 12
mm. long, 'and 2 to 3 mm. wide: New England coast; not
common.

FAMILY 2. BDELLOURIDAE.J

Body elongate and flattened and colorless; 2 eyes present; rhab-
dites absent; 2 uteri present with independent openings to the outside;

* See "Contributions to the Morphology of the Turbellaria," by W. M. Wood
worth, Bull. Mus. Comp. Zool., Vol. 21, p. 1, 1891.

t See "Marine Planarians of the New England Coast," by A. E. Verrill, Trans.
Conn. Acad., Vol. 8, 1893. "Tricladensstudien I. Tricladida maricola," by L. Bohmig,
Zeit. f. wiss. Zool., Vol. 81, p. 344, 1906. "On the N. A. Marine Triclads," by
J. Wilhelmi, Biol. Bull., Vol. 15, p. 1, 1908. "Tricladen," by same, Die Fauna u.
Flora d. Golfes v. Neapel, 1909.

t See "Syncoelidium pellucidum," etc., by W. M. Wheeler, Jour. Morph., Vol. 9, p.
167, 1894.

Fig. 271
Procerodes
wheatlandi

(Verrill).

168

PLATHELMINTHES

egg capsules attached by a slender pedicle : 2 genera and 4 species, para-
sitic or commensal on the gills and outer surface of Limulus polyphemus.
1. BDELLOURA Leidy. Anterior end tapering; posterior end wide,
with a glandular disc for attachment: 3 species.

B. Candida (Girard) (Fig. 272). Body 15 mm. long,
4 mm. wide, gray in color; egg capsule 2.5 to 4 mm. long;
testicular sacs 60 to 100 in number: often very common.
B. propinqua Wheeler. Body 8 mm. long; testicular
sacs about 170 in number; egg capsule 1.25 mm. long; not
so common 'as the above.

B. wheeleri Wilhelmi. Body 6 mm. long, 1 mm. wide,
the greatest width being in front of the pharynx; sucker
not set off from body: on Limulus; not common.

2. SYNCCELIDIUM Wheeler. Body elongate, tapering
towards both ends, which are blunt; posterior rami of intestine unite,
forming a single median trunk: 1 species.

S. pellucidum Wheeler (Fig. 273). Body 3 mm. long; testicular fol-
licles large, about 14 on each side of the body ; egg capsules
.75 mm. long.

SUBORDER 3. TERRICOLA.*

Land planarians. Intestinal branches simply lobed;
position of mouth variable; uterus small, behind the genital
pore; body oval or elongate, and usually brightly colored,
and with a creeping sole on the ventral surface : 5 families
and about 400 species which occur mostly in
tropical countries, living in damp places.

Fig. 272
Bdelloura

Candida
(Verrlll).

Pig. 273

Synccelidium

pellucidum

(Wheeler).

FAMILY 1. BIPALIIDAE.

Body often very elongate, usually brightly colored, and
with longitudinal or transverse stripes ; head end broadened,
forming plate with numerous marginal eyes; mouth median
or post-median ; genital pore ba,ck of mouth : 4 genera and
about 90 species.

PLACOCEPHALUS von Graff. Body often enormously
elongate; head plate thin, much broader than long, and
with a semicircular margin: 15 species.

P. kewensis (Mosley) (Fig. 274). Body 10 to 20 cm.
(in some cases 45 cm.) long, narrow and with parallel sides,
yellowish in color; with 7 longitudinal stripes; sole white: greenhouses in
America and Europe; native country unknown, although possibly Samoa.

* See "Monographic d. Turbellarien, II. Tricladida terricola," by L. von Graff,
Leipzig, 1899.

Fig. 274

Placo-

cephalus

kewensis

(von Graff).

WRBELLAR1A 169

FAMILY 2. BHYNCHODEMIDAE.

Body elongate, with more or less parallel sides; head not distinct,
with 2 spherical eyes near the front end; mouth near the middle: 7
genera and about 100 species.

RHYNCHODEMTJS Leidy. Head end very contractile and often ex-
tended like a proboscis; body more or less cylindrical; eyes small: 35
species.

E. sylvaticus Leidy. Body somewhat fusiform, thick, convex above
and flattened below, 10 mm. long, 3 mm. thick and 1 mm. wide; forward
end narrowed and very extensile; color gray with two longitudinal
stripes on the back and a transverse spot near the middle: eastern
states, in woody places.

ORDER 3. POLYCLADIDA *

Marine turbellarians, often of large size, with thin, leaf-like body;
intestine with very numerous branches which ramify to all parts of the
body; eyes numerous; otocysts, tentacles and stiff tactile cilia also often
present; no yolk glands; 2 genital pores; mouth central or posterior; no
asexual reproduction: 225 species grouped in 2 suborders.

Key to the suborders of Polycladidai:

01 No suckers present 1. ACOTYLEA

02 A ventral sucker present 2. COTYLEA

SUBORDER 1. ACOTYLEA.
Polyclads without a sucker; genital pores near hinder end of body:

3 families.

Key to the suborders of Polycladida :

ax Two dorsal tentacles present 1. PLANOCEBIDAE

oa No tentacles present 2. LEPTOPLANIDAE

FAMILY 1. PLANOCEEIDAE.

Two dorsal tentacles, usually containing ocelli; mouth central;
copulatory apparatus directed backwards; marginal and cerebral eyes
present or absent: about 8 genera and 45 species.

1. PLANOCERA Blainville. Body oval or elliptical and flattened;
tentacles slender, situated at some distance from front end of body with
a cluster of eyes at the base of each; cerebral ocelli inconspicuous;
genital pores separate but near together: about 25 species.

P. nebulosa Girard. Body convex and rather thick, 29 mm. long and
10 mm. wide, and usually olive green in color with a median dorsal
stripe; mouth central: Charleston to Cape Cod, under stones.

* See "Die Polycladien des Golfes von Neapel," etc., by A. Lang, Fauna u.
Flora d. Golfes v. Neapel, xi Monographie, 1884.

170

PLATHELMINTHES

P. inquilina Wheeler (Fig. 275). Body oval, 6 mm. long and 4 mm.
wide; edges remain in contact with the surface over which the animal
is moving; color grayish: Vineyard Sound, mantle cavity of Fulgur.

Fig. 275

Fig. 276

Fig. 275 — Planocera inquilina (Wheeler). 1, tentacle; 2, intestine; 3, mouth;

4, male genital pore ; 5, female genital pore. Fig. 276 — Stylochus

ellipticus (Verrill). 1, tentacle ; 2, mouth.

2. STYLOCHTTS Ehrenberg. Body oval or elliptical and flat; ten-
tacles short; pharynx with several accessory lobes; genital pores near
hinder end of body: 10 species.

S. ellipticus (Girard) (Fig. 276). Body flat and thin with undu-
lating margins, 20 mm. long and 6 mm. wide, yellowish-brown in color,
irregularly radially veined; tentacles small, white, each with a cluster
of ocelli ; 8 to 12 frontal and cerebral and numerous marginal ocelli pres-
ent: New England coast, the commonest of the larger
marine planarians, especially south of Cape Cod.

FAMILY 2. LEPTOPLANIDAE.

Body broad, flat, thin, without tentacles; mouth cen-
tral ; pharynx lobed ; usually 4 groups of ocelli, 2 cerebral
and 2 dorsal; marginal ocelli sometimes present; male
copulatory apparatus directed backwards: 4 genera and
about 60 species.

LEPTOPLANA Ehrenberg. Body f oliaceous with undu-
lating edges; no marginal ocelli; genital pores rather
widely separated, the male pore being distant from the
end of the body: 25 species.

L. variabilis (Girard) (Fig. 277). Body elliptical,
18 mm. long and 8 mm. wide, yellowish-brown in color; ocelli conspicuous,
the cerebral clusters containing about 30 each and the dorsal clusters about
15 : New England coast, often abundant.

Fig. 277

Leptoplana

variabilis

(Verrill).

TREMATODES 171

L. folium Verrill. Body very changeable, 25 mm. long and 15 mm.
wide, yellowish or pink in color; ocelli very numerous, small, and incon-
spicuous : New England coast.

SUBORDER 2. COTYLEA.

Polyclads with a sucker in the ventral surface behind the genital
pores: 4 families with about 110 species.

FAMILY PROSTHIOSTOMIDAE.

Body elongate and without tentacles; cerebral ocelli on the anterior
margin of the body ; mouth immediately behind brain ; pharynx long and
tubular: 1 genus.

PROSTHIOSTOMTTM Quatrefages. With the characters of the family:
8 species.

P. gracile Girard. Body thin and translucent, yellowish-white in
color, 4 mm. long and 1.25 mm. wide; ocelli in 4 groups: New England
coast; not common.

CLASS 2. TREMATODES.*

The flukes. Soft, flat or round worms which live as parasites on
the skin or gills of fishes and other aquatic animals or in the internal
organs of vertebrates and also of many invertebrates. The smallest are
of microscopic size, the largest may be a number of centimeters in
length. The outer surface of the adult body is an unciliated cuticula in
which suckers and chitinous hooks or spines are present, which enable
the animal to fix itself to its host. No body cavity is present, the
spaces between the organs being filled with the vesicular parenchyma.

The mouth is at the forward end of the body (except in Bucephalus).
The intestine is, with a few exceptions, bifurcate and is without anal open-
ing : the food consists of the blood and other juices of the host. The excre-
tory system consists of two main portions, the excretory vesicles and the
excretory tubules. The latter ramify throughout the parenchyma and end
with flame cells. The former consist of a pair of lateral canals which
receive the tubules and open to the outside through 'a pair of anterior pores
in the Monogenea and a median posterior pore in the Digenea. The nerv-
ous system consists of a pair of ganglia just back of the mouth which
are joined with each other by a commissure and of nerves which pass to

* See "Plathelminthes, I. Trematodes," by M. Braun, Bronn's Klassen, etc.,
Bd. 4, p. 306, 1892. "Die thierischen Parasiten des Menschen," by same, 1903.
"Illustrated Key to the Trematode Parasites of Man," by C. W. Stiles, Bull. No.
17, Hyg. Lab., Treas. Dept., 1904. "Index Catalogue," etc., "Trematoda," by same,
Bull. No. 37, same, 1908. "Trematodes," by M. Lube, Die Siisswasserfauna Deutschl.,
1910.

172 PLATHELMINTHES

the various organs. Several pairs of large longitudinal nerves pass to
the hinder part of the body.

With a few exceptions all trematodes are hermaphroditic, the male
and female pores being either confluent, in which case a genital atrium
is often present, or side by side and near together in the ventral sur-
face. The arrangement of the genital organs is complex and varies
somewhat in the three orders of trematodes. The egg is composite in
structure, consisting of an ovum and several yolk cells.

Habits and Distribution.— The young trematode leads a free life for a
short time and then seeks its host. The most primitive trematodes are
external parasites and the entire life may be passed on a single host.
The higher forms, on the other hand, are internal parasites and live in
two or more hosts, the adult host being different from the larval host,
and the passage from one host to the other being accompanied by a
metamorphosis. The former are called monogenetic and the latter dige-
netic trematodes. Many of the latter are dangerous parasites to man
and his domestic animals.

History.— This class was established in 1808 by Rudolphi, who
included in it the genera, Monostoma Zeder, Amphistoma Rudolphi,
Distoma Retzius, and Polystoma Zeder. It was not until 1858 that the
distinction between the ectoparasitic and the entoparasitic forms found
expression in the classification, when P. J. van Beneden formed the groups
Monogenea to include the former 'and the Digenea for the latter. In 1892
Monticelli showed the need of subdividing the Digenea and established the
following suborders : the Heterocotylea, the Aspidocotylea, and the Malaco-
cotylea, the first of which coincides with the Monogenea. This subdivision
was generally adopted, but is now being abandoned in favor of the simpler
one of van Beneden. The explanation of the complex metamorphosis of
trematodes was first given by Steenstrup in 1842. Thomas and Leuckart
discovered almost simultaneously in 1881 the life history of the common
liver fluke (Fasciola hepatica), and the latter author and Looss have
played the principal part in the investigation of the entire group.

About 2,500 species of trematodes are known, which may be
grouped in 3 orders.

Key to the orders of Trematodes:

Oj Ectoparasitic trematodes (except Polystoma) ; hooks usually present in

the suckers or sucking discs 1. MONOGENEA

o2 Mostly entoparasitic trematodes; no hooks in the suckers or sucking

discs.
61 Either a large ventral sucking disc or a midventral row of suckers ; no

oral sucker 2. ASPIDOCOTYLEA

5a Usually either 1 or 2 median suckers; oral sucker present (except in

Bucephalus) 3. DIGENEA

TEEMATODES

173

Fig. 278 — Diagram of a monogenetic
trematode (Benham). 1, mouth; 2,
anterior sucker ; 3, brain ; 4, vagina ;
5, excretory pore ; 6, intestine ; 7, pos-
terior sucking disc ; 8, hook ; 9, genital
pore ; 10, excretory canal ; 11, penis ;
12, vagina ; 13, uterus ; 14, ovary ; 15,
sperm duct ; 16, yolk glands ; 17, testes ;
18, genito-intestinal canal.

The order contains 4

ORDER 1. MONOGENEA *

Monogenetic trematodes (Fig. 278). Usually external parasites on
fish and other aquatic animals. Most forms live on but a single host and
are found most often on the gills,
being that part of a fish's body where
the blood is nearest the surface and
where a parasite is also protected;
some, however, live in the mouth and
some in the cloaca. The genus
Polystoma is entoparasitic. The or-
gans of attachment are at the extremi-
ties of the body. At the hinder end
is a large disc more or less sharply
set off with either suckers or hooks,
or both these organs. At the for-
ward end is usually a pair of suckers
with the mouth between them. These
may, however, be absent or their place
may be taken by a single oral sucker,
by paired glands, or by tentacle-like structures,
families and about 500 species.

Key to the families of Monogenea*:

Oj Large posterior sucking disc without suckers or marginal hooks.

6X A pair of anterior suckers or sucker-like projections with mouth between.

1. TRISTOMIDAE

6, A single anterior sucker, or none 2. MONOCOTYLIDAE

oa Disc-like posterior region with either paired suckers or marginal hooks.

&! Posterior region with suckers 3. POLYSTOMIDAE

62 Posterior region without suckers * .... 4. GYBODACTYLIDAE

FAMILY 1. TEISTOMIDAE.

Mostly broad, flat worms, with a pair of anterior suckers or sucker-
like membranes, one on either side of the mouth, and a large posterior
sucking disc in which hooks are often located, the anterior suckers
being without hooks; a pair of eye spots often present; intestine bifur-
cate and often much branched; genital pores near the forward end, the
male and female openings being in some cases separated from each
other: on the skin or gills of marine fishes or in the mouth or cloaca;
about 11 genera.

* "Notes on Trematode Parasites of Fishes," by E. Linton, Proc. U. S. Nat.
Mus., Vol. 20, p. 507, 1898. "Notes on Some Exotic Species of Ectoparasitic
Trematodes," by S. Goto, Jour. Sci. Coll., Imp. Univ., Vol. 12, p. 263, 1899.
"Synopsis of the Trematodes, Part I. The Heterocotylea," by H. S. Pratt, Am.
Nat., Vol. 34, p. 645, 1900. "Fish Parasites of the Woods Hole Region," by E.
Linton, Bull. Fish. Com., Vol. 19, p. 405, 1901.

174

PLATHELMINTHES

.,.-2

Key to the genera of Tristomidae here described:

Oi Sucking disc not set off from body and with 7 radial ridges. . .1. TRISTOMA
a2 Sucking disc set off from body and without radial ridges.
bj. Body elongate; sucking disc terminal with many minute hooks.

2. NITZSCHIA

6, Body elliptical ; sucking disc ventral with large hooks 3. EPIBDELLA

1. TRISTOMA Cu-
vier. Body very flat,
circular, or oval, with
a pair of anterior suck-
ers and a large ventral
sucking disc in which
are 7 radial ridges and
small hooks ; intestine
with side branches;
genital pores near the
margin of the body;
many testes present :
about 10 species.

T. coccineum Cuv.
(Fig. 279). Body about

15

16

Fig. 279 — Tristoma coccineum (from Bronn),
References as in Fig. 278.

mm. long and
mm. wide and red in
color: on the gills of
the swordfish.

2. NITZSCHIA von Baer. Body elongate, with sucking disc terminal
and without radii; 2 large suckers at forward end; numerous testes: 1
species, in salt and fresh water.

N. sturionis (Abildgaard) (Fig. 280). Body red-
dish, 16 mm. long, 5 mm. wide; sucking disc globose: on
gills of the sturgeon.

3. EPIBDELLA Blainville. Body elliptical and flat;
sucking disc ventral without ridges, but often with
papillae; 4 small eyes; 2 testes: several species.

E. bumpusi Linton (Fig. 281). Length 12 mm.;
width 8 mm. : on skin of Dasyatis centrura; Woods Hole.

FAMILY 2. MONOCOTYLIDAE.

Flat and circular or elliptical worms without paired
anterior suckers and with a single posterior sucking plate,
which is sometimes very small : on the skin, gills, or in the
cloaca of marine fishes; 7 genera.

MONOCOTYLE Taschenberg. Sucking disc with 8 radial ridges;
1 to 3 testes: on the skin or gills of skates.

Fig. 280

Nitzschia

sturionis

(Monti celli).

References

as in Fig. 278.

TEEMATODES

175

M. floridana Pratt (Fig. 282). Body 1.3 mm. long and .58 mm. wide;
oral sucker present; intestinal branches joined at hinder end and pro-
longed in a median coecum : on the gills
of Myliobatis freminvillei.

FAMILY 3. POLYSTOMIDAE.

Body flat and broad, with a more
or less distinct disc or region at the
hinder end bearing suckers, usually
paired, the number of which may vary
from 2 to 120, and also in most cases
hooks; anterior suckers either present
or not: on gills of fishes and in the
mouth, nose, and urinary bladder of
amphibians and reptiles; about 21
genera and 3 subfamilies.

Key to the subfamilies of Poly-
stomidae :

ox Anterior suckers absent ; either 2 or 6
posterior suckers . 1. POLYSTOMINAE
a2 Anterior suckers present.

&x Posterior suckers 4 to 8

Z>2 Posterior suckers very numerous

Fig. 281—Epibdetta bumpusi

(Linton).
References as in Fig. 278.

. . 2. OCTOCOTYLINAE
.3. MlCBOCOTYLINAE

SUBFAMILY 1. POLYSTOMINAE.

Posterior sucking disc distinctly set off and with
2 or 6 large suckers arranged in pairs and also 2
or more large hooks; paired anterior suckers absent:
about 5 genera.

1. POLYSTOMA Zeder. Body without anterior
and with 3 pairs of posterior suckers ; vagina paired
with an opening on either margin of the anterior
portion of the body: on the gills of frog tadpoles
as larvae, and in the urinary bladder of amphibians
and in the mouth, nose, and urinary bladder of
turtles as adults; 6 species, 3 in America.

P. oblongum R. R. Wright. Disc attached at
its anterior end; intestine with no side branches;
body elliptical; cirrus with 16 spines, alternately
large and small; length 2.5 mm.; width 1 mm.: in urinary bladder of
musk, painted, and snapping turtles.

Fig. 282
Monocotyle floridana

(Pratt).

References

as in Fig. 278.

176

PLATHELMINTHES

P. coronatum Leidy. Body lanceolate, 6 mm. long, with 3 pairs of
minute hooks between the anterior pair of suckers, and 1 large and 2
small pairs between the posterior pair: in the
nose of the food terrapin.

P. hassalli Goto (Fig. 283). Body ovate; 1.5
mm. long and 1 mm. wide; disc hexagonal with
3 pairs of small hooks between the anterior pair
and 1 pair of large hooks between the posterior
pair of suckers; intestine without side branches:
in the urinary bladder of Kino-
sternum pennsylvanicum.

2. SPHYEANTJEA Wright
and MacCallum. Body elon-
gate with a small posterior
disc containing 2 large suck-
ers: 2 species.

S. osleri Wr. and MacC.

(Fig. 284). Body tapering at both ends, 4 mm. long
and .6 mm. wide; disc wider than body; testes nu-
merous: on skin and gills of Necturus maculatus.

SUBFAMILY 2. OCTOCOTYLINAE.

Posterior region with 8 (4) large suckers; paired
anterior suckers present: about 12 genera.

Key to the genera of Octocotylinae here described :

-7

Fig. 283 — Polystoma
hassalli (Goto).

References
as in Fig. 278.

dj Posterior disc-like region with median

hooks 1. DISCOCOTYLE

o2 Median hooks not present.

2. DlCLIDOPHOEA

Fig. 284

mura oslen

(Wright and

MacCallum).

References

as in Fig. 278.

1. DISCOCOTYLE Diesing. Body
elongate with small hooks in the poste-
rior disc; posterior suckers slightly stalked and with
strong chitinous support; vagina Y-shaped: several
species.

D. salmonis Shaffer (Fig. 285). Body lanceolate; pos-
terior suckers slightly raised and with 1 pair of hooks;
5 mm. long : on the gills of the rainbow trout.

2. DICLIDOPHORA Goto. Body elongate; posterior
suckers either stalked or not and acting as pincers; each

sucker with a chitinous frame work in form of a Greek cross: on the
gills of the Sparidae and other marine fishes.

Fig. 285

Discocotyle

salmonis

(Shaffer).

References

as in Fig. 278.

TEEMATODES

177

D. affinis (Linton). Body attenuate, spatulate; anterior portion
elliptical; posterior portion cylindrical; posterior suckers with long
stalks : length 12 to 40 mm. : in the mouth of the flounder.

SUBFAMILY 3. MICEOCOTYLINAE.

Paired anterior suckers present; posterior disc-like region elongate
and bearing numerous small suckers, which may be found only on one
side, making the animal asymmetrical: 4 genera.

MlCROCOTYLE van Beneden and Hesse. Posterior
region bearing 10 to 120 pairs of minute sessile suckers :
on gills of marine fishes; many species.

M. longicauda Goto. Sucker disc more than half
the length of the body; about 120 pairs of suckers pres-
ent; 7 mm. long; 2 mm. wide: on the gills of the weak-
fish; Newport.

M. pogoniae MacCallum (Fig.
286). Sucker disc about a third of
the body ; length 12 mm. : on Pogonias
cromis, often very numerous.

FAMILY 4. GYBODACTYLIDAE.

Minute forms occurring on the
gills of fresh- water and marine fishes ;
body minute, usually without suck-
ers, but with 2 to 4 retractile ten- 7.
tacles at the forward end
and a disc at the hinder end
armed with numerous hooks:
about 9 genera. In the genus
Gyrodactylus a curious paedo-

genesis often occurs. A young individual will come
to sexual maturity before it is born and while it is
still in the maternal uterus, and produce young in its
uterus. This last individual may also have young in
its uterus, and 4 generations may thus be found, one
inside of another.

GYRODACTYLTTS Nordmann. Minute, elongated

worms with 2 short anterior projections and a posterior disc bearing

about 16 marginal hooks and 2 large central ones; no eyes present:

4 species.

G. elegans Nordmann (Fig. 287). Length 1 mm.; width .2 mm.: on

the gills and skin of the carp and other fresh-water fishes.

Fig. 286 — Microcotyle

pogoniae (MacCallum).

References as in Fig. 278.

Fig. 287—Oyro-
dactylus elegans
(fromBronn). a. p.,
anterior projec-
tion ; p.p., phar-
ynx. Other refer-
ences as in Fig.
278.

178

PLATHELMINTHES

ORDER 2. ASPIDOCOTYLEA. (Fio. 288.)

Monogenetic and digenetic trematodes which attach themselves to
their host by means either of a median row of suckers or a very large
ventral sucking disc in which are sucking pits or de-
pressions and on the margin of which are often sense
organs; hooks and anterior suckers not present and
intestine not bifurcate: in the intestine of fishes and
reptiles and in mollusks and crustaceans; 1 family and
a small number of species.

FAMILY ASPIDOBOTHKIDAE.

With the characters of the order: 8 genera.
Key to the American genera of Aspidobothridae :

Oj Body cylindrical with a midventral row of suckers.

1. STICHOCOTYLE

o2 Large ventral sucking disc containing 3 or 4 longitu-
dinal rows of depressions.
&! Three rows present.
Cj Median depressions very elongate transversely, the

lateral depressions being round 2. COTYLOGASTEB

C2 All the depressions transversely elongate. 3. COTYLASPIS
62 Four rows present 4. ASPIDOGASTEB

Fig. 288

Diagram of the

Aspidocotylea

(Aspidogaster)

(after Benham).

1, mouth

2, intestine

3, genitai pore

4, ovary
5, yolk glands

6, uterus

7, testis

8, ventral suckers
or sucking disc.

1. STICHOCOTYLE Cunningham. Body cylindrical

and elongate with a midventral row of 20 to 30 suckers extending the
length of the body : 1 species.

S. nephropis* Cunn. (Fig. 289). Length of adult 17 to 105 mm.,
with 20 to 27 suckers; length of the larva 3 to 7 mm.,
with 7 to 22 suckers: adult lives in the liver of Raja
and the larva encysted in the intestinal walls of lob-
sters and large crabs on the Atlantic coast; Europe.

2. COTYLOGASTER Monticelli. Sucking disc long
and narrow with 2 lateral rows of round depressions
and a median row of very elongate transverse depres-
sions; 2 testes; marginal sense organs: 2 species, in
the intestine of marine and fresh-water fishes.

C. occidentalisf Nickerson (Fig. 290). Sucking disc with 132 to 144
depressions; length 10 mm.: in the sheepshead in Minnesota.

Fig. 289

Stichocotyle

nephropis ;

a larva from a

lobster

(Nickerson).

References

as in Fig. 288.

* See "Ueber die geschlechtsreife Form von Stichocotyle nephropis Cunn.," by
T. Odhner, Zool. Anz., Vol. 21, p. 500, 1898.

t "Cotylogaster occidentalis n. sp. and a Revision of the Family Aspido-
bothridae," by W. S. Nickerson, Zool. Jahrb. Abt. f. Sys., Vol. 15, p. COT, 1902.
"Synopsis of the Trematodes, Part II. The Aspidocotylea," etc., by H. S. Pratt,
Am. Nat, Vol. 36, p. 887, 1902.

TEEMATODES

179

Fig. 290

Cotylogaster

occidentalis

(Nickerson).

References

as in Fig. 288.

Fig. 291

Cotylaspis

insignia

(Osborn).

References

as in Fig. 288.

3. COTYLASPIS Leidy. Sucking disc broadly elliptical with 3 rows
of transversely elongated depressions; marginal sense organs and 2 eyes
present: in the mantle cavity of mussels and the intes-
tine of turtles; 2 species.

C. insignis* Leidy (Fig. 291). Length 1.8 mm.; num-
ber of depressions about 29 : on the kidney
of Anodonta; common.

4. ASPIDOGASTER von Baer. Small
worms in which the body consists of a cyl-
indrical anterior portion and a very large
elliptical ventral disc in which are 4 longi-
tudinal rows of sucking depressions, num-
bering 64 to 120 and with marginal sense
organs ; 1 testis : in the intestines of fishes
and in fresh-water pelecypods and marine
gastropods; several species.
A. conchicola v. Br. (Fig. 292). Body elongate; number of depres-
sions about 64; length 3 mm.; 34 marginal sense organs: mostly in the
liver, pericardium, and kidney of Unio and Anodonta; Europe.

ORDER 3. DIGENEA.f (FiG. 293.)
Entoparasitic, digenetic trematodes living in two or
more hosts, to which they attach themselves by means of
either one or two median
suckers. One of these is al-
ways an oral sucker and at
the front end of the body, ex-
cept in Bucephalus; the second
sucker, when present, is either

on the ventral surface or at the hinder end

of the body and is called the acetabulum.

A few blood-infesting forms are without

suckers. In the Holostomidae an additional

organ of attachment in form of a large disc

or projection back of the acetabulum is also

present. Hooks are never present in con-
nection with the suckers but in some cases

with the genital organs, and the body is

often covered with small spines. The median

Fig. 292
Aspidogaster

conchicola
(Monticelli).

References
as in Fig. 288.

Fig. 293 — Diagram of a
digenetic trematode (Ben-
ham, altered). 1, oral suck-
er ; 2, brain ; 3, genital
pore ; 4, intestine ; 5, cir-
rus ; 6, receptaculum semi-
nis ; 7, acetabulum ; 8, ovary ;
9, excretory canal ; 10, Lau-
rer's canal ; 11, yolk glands ;
12, testis ; 13, excretory
pore ; 14, uterus.

* See "On the Habits and Structure of Cotylaspis insignis," etc., by H. L.
Osborn, Zool. Jahrb. Abt. f. Anat., Vol. 21, p. 201.

t See "Synopsis of the Trematodes, Part II. The Aspidocotylea and the Mala-
cocotylea," etc., by H. S. Pratt, Am. Nat, Vol. 36, p. 887, 1902.

180

PLATHELMINTHES

Fig. 294

Cercaria of
Bucephalus

(Tennent).
1, mouth; 2,
cyst - forming
gland ; 3, tail ;
4, intestine.

excretory pore is at the hinder end of the body and the genital pore is
in the ventral surface or on the margin of the body. Special sense
organs are with rare exceptions absent. The life history is known of
but very few trematodes. The young animal passes out of the host in
the egg, on leaving which it is usually a ciliated larva called the
miracidium; this larva seeks an intermediate
host, often a mollusk, in the body of which it
passes its larval life, living actively or encysted
in some of the compact tissues. It here
passes through one or more metamorphic stages
which finally result in the production of young
individuals, called cercariae, each of which has
usually a locomotive tail (in Bucephalus two)
(Fig. 294), which sometimes seek still another
intermediate host, and are destined to develop
into the adult worms. If, now, the host harbor-
ing these larval worms be devoured by the final
host, the young worms pass into the intestine or
some other hollow organ of the latter and become

mature. Tailless cercariae, which are quite numerous, do not leave the
first intermediate host, but pass directly with it into the final host.
Digenetic trematodes are common parasites, the adult worms being
found in almost all vertebrate animals. The larval worms are usually
found in snails, small fish, and other small animals. Some of them are
dangerous parasites to man and his domestic animals. The order con-
tains about 2,000 species, grouped in 2 suborders.
Key to the suborders of Digenea:

G! Mouth median in position 1. GASTEROSTOMATA

o2 Mouth anterior in position 2. PBOSTOMATA

SUBORDER 1. GASTEROSTOMATA.

Mouth in the middle of the ventral surface; intestine sac-like and not
bifurcate: 1 family.

FAMILY BUCEPHALIDAE.

But one sucker present which is at the front end of the body; mouth
in the middle of the ventral surface; intestine sac-like and not bifurcate;
genital pore at hinder end: in intestine of fish, in both fresh and salt
water; the larval forms in bivalve mollusks; 2 genera.

BUCEPHALUS von Baer (Gasterostomum von Siebold). Yolk glands
in two distinct groups of follicles; male genital pore at end of a papilla:
numerous species.

TEEMATODES

181

B. gracilescens (Rudolphi) (Fig. 295). Length 1.4 mm.; width .5
mm.: in Tylosurus marinus and other marine fishes; larva (Fig. 294) in
gonads and other organs of the oyster, often causing
death.

SUBORDER 2. PROSTOMATA.

Mouth at the anterior end, in the oral sucker; in-
testine bifurcate (with a few exceptions) : 4 divisions.

Key to the divisions of Prostomata:

01 But 1 sucker present 1. MONOSTOMATA

02 Two suckers present.

&! Acetabulum at hinder end 2. AMPHISTOMATA

&2 Acetabulum in ventral surface.
Ci Additional organs of attachment not present.

3. DlSTOMATA

c, Additional sucking disc or projection present.

4. HOLOSTOMATA

Fig. 295

Bucephalus

gracilescens

(Tennent).

1, sucker ; 2, mouth.

Other references

as in Fig. 293.

DIVISION 1. MONOSTOMATA.

Oral sucker alone present; arrangement of organs similar to that of
the Distomata: in vertebrates, especially birds and sea turtles; several
families.

FAMILY 1. CYCLOCCELIDAE.

Large trematodes in which the intestinal trunks
join at the hinder end; genital pore in anterior half
of the body; ovary in front of testes: in the air
passages of birds; 6 genera.

CYCLOCCELUM Brandes. Intestinal trunks with-
out lateral branches; uterus entirely between the
trunks: 10 species.

C. mutabile (Zeder). Body elongate, attenuate
forward and about 18 mm. long; testes small, the
hinder one near the juncture of the intestinal trunks:
in Gallinago and other birds.

FAMILY 2. PEONOCEPHALIDAE.

Body usually elongate, with a collar-like rim
around the head; testes and ovary in hinder end of
body, the testes being in same transverse plane with
the intestinal trunks between them: in turtles.

PRONOCEPHALITS Looss. With the characters of
the family: several species.
P. renicapitis (Leidy) (Fig. 296). Length 25 mm.; width 3 mm.;
testes lobate : intestine of SpTiargis coriacea.

Fig. 296 — Prono-

cephalus renicapitis

(Braun).

References

as in Fig. 293.

182

PLATHELMINTHES

DIVISION 2. AMPHISTOMATA.

Body often more or less conical, with the oral sucker at the front
end and the acetabulum at the hind end of the body; intestine bifur-
cate, the pharynx often having a pair of lateral pockets; testes 1 or
2 in number, large, and situated in front of the small ovary; yolk
glands usually large; genital pore in the forward
part of body: in all classes of vertebrates, usually
in the digestive tract; 3 families.

FAMILY PARAMPHISTOMIDAE.

With the characters of the division: 8 genera.
1. PARAMPHISTOMTJM Fishoder. Oral sucker
rudimentary; acetabulum large, with the excretory
pore just dorsal to it; no pharyngeal pockets: in
the stomach and intestine of
vertebrates, principally mam-
mals; about 25 species.
P. cervi (Zeder) (P. conicum Zed.) (Fig.
297). Body conical, 10 mm. long: in stomach of
sheep and cattle; rare in this country.

2. DIPLODISCUS Diesing. Acetabulum large,
with the excretory pore in its center; pharyngeal
pockets present: in rectum of amphibians; sev-
eral species.

D. temporatus* Stafford (Fig. 298). Body
conical; about 3.6 mm. long: in rectum of frogs;
not uncommon.

Fig. 297 — Param-

phistomum cervi

(from Braun).

Fig. 298 — Diplodiscus
temporatus (Gary).

References
as in Fig. 293.

DIVISION 3. DISTOMATA.I

Body flattened or cylindrical and often cov-
ered with minute spines, with the oral sucker
at the front end and the acetabulum in the ven-
tral surface; intestine, with a few exceptions,

bifurcate, the 2 trunks being either short or long and branched or
simple; usually a pair of testes (in a few species several pairs) ; a single
ovary, which is smaller than either testis, and often a large receptaculum

* See "The Life History of Diplodiscus temporatus," etc., by L. R. Gary, Zool.
Jahrb. Abt. f. Anat., Vol. 28, p. 595, 1909.

t See "An Inventory of the Genera and Subgenera of the Trematode Family
Fasciolidae," by C. W. Stiles and A. Hassall, Arch, de Paras., Vol. 1, p. 81, 1898.
"Weitere Beitrage zur Kenntniss der Trematoden Fauna ^Egyptens," etc., by A.
Looss, Zool. Jahrb. Abt. f. Sys., Bd. 12, p. 521. "Nachtragliche Bemerkungen," etc.,
by A. Looss, Zool. Anz., Bd. 23, p. 601, 1900.

TEEMATODES 183

seminis present; the uterus is a long tube, containing eggs; yolk glands
either branched or compact: parasitic as adults in the intestine and
other hollow organs of vertebrates; over 1,700 species, the family rela-
tionships of which are as yet more or less obscure.
Key to the genera of Distomata here described:

d Hermaphroditic distomes.
&! Ovary in front of testes.
Ci Uterus does not extend back of testes.
di Intestinal trunks with lateral projections ; ovary and testes branched.

1. FASCIOLA
<fa Intestinal trunks without lateral projections.

6i Genital pore back of acetabulum 2. PABAGONIMUS

ea Genital pore not back of acetabulum.
/! Mouth surrounded by spines.

& A single row of spines 3. ECHINOSTOMA

02 A double row of spines 4. STEPHANOCHASMUS

/2 No spines around the mouth.

0X Excretory vesicle winds between the testes 5. AMPHIMEBUS

02 Excretory vesicle does not wind thus 6. AZYGIA

C2 Uterus extends back of testes.

di Mouth surrounded by 6 long papillae 7. BUNODEEA

ds No such papillae.
e^ Intestinal trunks reach to about the middle of the body.

/! Yolk glands branched and in middle area of body 8. RENIFEB

/2 Yolk glands compact and at end of body 13. MICBOPHALLUS

€2 Intestinal trunks reach the rear end of body.
A Genital pore near front end of body.
0! Genital pore near pharynx ; in lungs of frogs and toads.

9. PNEUMONO3CES

02 Genital pore in front of oral sucker , ... 10. CEPHALOGONIMUS

fs Genital pore near acetabulum ; yolk glands compact and lobate.

0! Testes 2 in number 11. GOBGODEBINA

02 Testes 9 in number 12. GOBGODEBA

62 Ovary behind testes.

e?i Hinder end of body not telescopic 14. HALIPEGUS

C2 Hinder end telescopic 15. HEMIUBUS

63 Ovary between the testes 16. CLINOSTOMUM

aa Unisexual distomes 17. SCHISTOSOMA

1. FASCIOLA L. Body broad and leaf-like, covered with minute
spines and with a short conical anterior end at the base of which is the
acetabulum; intestine, excretory vesicles, and genital glands richly
branched; genital pore in front of acetabulum: in liver of herbivores;
about 4 species.

F. hepatica L. Liverfluke. Length 18 to 50 mm.; width 4 to 13
mm.; conical anterior end distinctly set off; body thin and flat: in the
gall passages of cattle, sheep, man, and other animals, causing
liver rot, which is often very fatal to herds ; intermediate host a snail of
the genus Lymnaea ; cosmopolitan, but rare in America, except in southern
Texas, in Florida, and a few other places.

184

PLATHELMINTHES

T. magna* (Bassi) (Fig. 299). Length 20 to 100 mm.; width 11 to
26 mm.; body flesh-colored and thick, with anterior end not distinctly

.-3

Fig. 299 Fig. 300

Fig. 299 — Fasciola magna (from Ward). References as in Fig. 293. Fig. 300 —
Paragonimus westermani (from Ward). References as in Fig. 293.

set off: in the gall passages of cattle; common in the southwestern
states; life history unknown.

2. PARAGONIMUS Braun. Genital pore
just behind the acetabulum; body thick,
ovoid; intestinal trunks long and un-
branched; testes lobate; yolk glands very
voluminous ; uterus very short : encapsuled
in the lungs of mammals; 1 species.

P. westermani (Kerbert) (Fig. 300).
Body red in color, 8 to 20 mm. long; 4 to
8 mm. wide: in lungs of cats, dogs, and
in eastern Asia, in man.

3. ECHINOSTOMA Rudolphi. Body
elongate and spiny ; acetabulum near front
end; mouth surrounded by a reniform
ridge in which is a row of spines, inter-
rupted midventrally : many species.

E. echinatum (Zeder). Number of
spines about 37; body 18 mm. long;
1.5 mm. wide: in intestine of ducks,
chickens, geese, and swans.

4. STEPHANOCHASMUS Looss. Body
elongate and spiny; acetabulum near for-
ward end; mouth surrounded by 2 rows of spines: several species, in
fishes.

* See "The Anatomy of the Large American Fluke," etc., by C. W. Stiles, Jour.
Comp. Med., etc., March, 1894— May, 1895.

Fig. 301

StepJianochasmus casus,

with extended cirrus (Pratt).

P.p., prepharynx ; Ph., pharynx.

Other references as in Fig. 293.

TREMATODES

185

I

S. casus Linton (Fig. 301). Number of spines 36, 18 in each row;
body 6 mm. long ; 1 mm. wide : in rectum of the gray snapper.

5. AMPHIMERTTS* Barker. Body lanceolate; acetabulum in forward
half with the genital pore in front of it; ovary near the center of the
body; yolk glands divided into two regions; testes, which

may be lobate, in a row behind it with the excretory
vesicle winding between them: several species, in land
vertebrates.

A. pseudofelineus (Ward) (Fig. 302). Body not
spinose; length 10 to 21 mm.; width 1 to 2.5 mm.: in the
liver of cats.

6. AZYGIA Looss. Body elongate; acetabulum near
the middle, ovary far back of it, and between the two
is the uterus; testes back of ovary: in fish.

A. loossi Marshall and Gilbert. Length 6 mm.;
breadth .5 mm.; body not spinose; yolk glands back of
acetabulum: in mouth and stomach of wide-mouthed black
bass, pike, and dogfish.

7. BTTNODERA Raillet. Body
ovate; mouth surrounded by 6 con-
tractile projections; acetabulum near
center of body, with genital pore in
front of it; testes in hinder part of
body; uterus sac-like: in fresh-water
fish.

B. nodulosa (Zeder). Length 1 to 3 mm.: in
the intestine of the perch and other fishes; inter-
mediate host the crayfish, being found in cysts in
various organs.

8. RENlFERf Pratt. Body elongate and spinose;
acetabulum near the middle of the body with the
genital pore between it and the oral sucker; ovary
just back of acetabulum; testes lobate and just
back of ovary : in reptiles.

R. ellipticus Pratt (Fig. 303). Body elliptical; genital pore at left
edge of body ; 4 mm. long : in mouth of Heterodon platyrhinus, the blowing
viper, and other snakes.

9. PNEUMONCECEst Looss. Body elongate; suckers small, acetabu-

* See "The Trematode Genus Opisthorchis," by F. D. Barker, Arch. d. Parasit.,
Vol. 14, p. 513, 1911.

t See "Descriptions of Four Distomes," by H. S. Pratt, Mark Ann. Vol., p. 25,
1903.

t See "On the American Representatives of Distomum variegatum," by J.
Stafford, Zool. Jahrb. Abt. f. Sys., Bd. 16, p. 895, 1902.

-tt

Fig. 302
Amphimerus
pseudo-
felineus
(Ward).
References
as in Fig. 293.

Fig. 303 — Renifer
ellipticus (Pratt).

References
as in Fig. 293.

186

PLATHELMINTHES

lum often minute; ovary and testes back of acetabulum; large recep-
taculum seminis present; uterus usually in longitudinal folds: in lungs
of amphibians; 8 species.

P. similiplexus (Stafford) (Fig. 304). Length 8 mm.; width 2 mm.;
body spinose; testes small; uterus very voluminous and dark-colored:
in the lungs of frogs and toads.

10. CEPHALOGONIMTTS Poirier. Body broad,
spinose; acetabulum near center of body; yolk
glands; genital pore in front of oral sucker;
excretory vesicle extensively branched; ovary just
back of acetabulum and testes back of it: in
turtles.

0. vesicaudus Nickerson. Body elliptical, 2 mm.
long: in intestine of soft-shell turtles in Minnesota.

11. GORGODERINA Looss. Body elongate and
without spines; acetabulum large and in forward
half of body; back of it are the yolk glands, which
are a pair of compact bodies; the ovary is back of
these; testes 2 in number; uterus fills the hinder
half of the body: 4 species, in urinary bladder of
frogs and toads.

G. translucida (Stafford) (Fig. 305). Body
widest in the middle and tapering to
both ends; 9.5 mm. long and 1.2 mm.
wide: in the toad and the spring
frog.

12. GORGODEEA Looss. Like Gorgoderina, but with
9 testes in 2 rows in the hinder half of the body: 2
species.

G. amplicava Looss. Body widest in middle ; acetabu-
lum very large; length 3.75 mm., and .75 mm. wide: in
the urinary bladder of the bullfrog.

13. MICROPHALLTTS Ward. Body broad with blunt
ends ; intestinal creca very short and not reaching acetabu-
lum; yolk glands lobate, in hinder part of body; genital
pore at left of acetabulum: in fresh- water fish.

M. opacus (Ward) (Fig. 306). Length 1.7 mm.;
width 1 mm.; oesophagus very long: in intestine of Amia
calva; intermediate host Cambarus propinquus.

14. HALIPEGUS Looss. Body elongate; acetabulum in middle of
body; yolk glands 2 compact lobate bodies near hinder end; ovary in
front of them and testes in front of ovary: in amphibians.

Fig. 304

Pneumonaecea

similiplexus

(Stafford).
References as in

Fig. 293.

Fig. 305

Gorgodorinct

translucida

(Stafford).

References

as in Fig. 293.

TREMATODES

187

Fig. 306 — Microphallus
opacus (Ward).

References
as in Fig. 293.

H. occidualis Stafford. Body 6 mm. long; 1.5 mm. wide; testes in
oblique plane near acetabulum: in the mouth of frogs.

15. HEMITJRUS Rudolphi. Small, cylindrical worms, the hinder end
of whose bodies forms an appendix which can

be invaginated; cuticula transversely striped;
37olk glands compact, behind ovary, which is just
behind the testes: in fish.

H. appendiculatus (Rud.). Appendix from
a third to twice the length of the body; acetabu-
lum much larger than oral sucker; yolk glands
spherical; 6 mm. long: in digestive tube of her-
ring and other marine fish; intermediate host
usually copepods.

16. CLINOSTOMTTM Leidy. Elongated worms
with mouth surrounded by a circular ridge; ovary
between the testes in middle of body; intestine
without pharynx and with side projections: in
mouth of birds; about 10 species.

C. marginatum (Rudolphi) (Fig. 307). Body 6 to 10 mm. long;
1 to 2 mm. wide; yolk glands voluminous: in Ardea and other birds;
intermediate host, the /

sunfish and other fishes.

17. SCHISTOSOMA

Weinland. Sexes sepa-
rate ; acetabulum near
front end; male is larger than the
female and has a deep groove in
its ventral side in which the fili-
form female lies: several species,
in blood of mammals in tropical
countries.

S. haematobium (Bilharz)
(Fig. 308). Body cylindrical;
length of male 14 mm.; length of
female 20 mm.: in the blood of
man, chiefly in Africa, occasionally
in this country.

-IL

Fig. 307

Clinostomum

marginatum

(Osborn).

References

as in Fig. 293.

DIVISION 4. HOLOSTOMATA.

Fig. 308
Schistosoma
hcematobium

(Looss).
1, oral sucker ;

2, acetabulum ;

3, male individ-
ual ; 4, female
individual.

Digenetic trematodes with an oral sucker and an acetabulum, and
in addition a large variously constructed adhesive ventral disc or pro-

188

PLATHELMINTHES

jection situated just back of the acetabulum; body in most cases made
up of 2 distinct regions, a wider anterior portion containing the 2
suckers and the disc, the lateral edges of which are often rolled in
ventrally and medially, and a posterior portion containing the genital
organs; the genital openings being at the hinder end in a deep depres-
sion called the bursa copulatrix; the arrangement of the internal organs
is similar to that of the Distomata: in the intestine of vertebrates, princi-
pally mammals and birds; about 6 genera and 60 species.
Key to the genera of Holostomata here described :

«! Lateral edges of anterior portion not rolled in medially 1. DIPLOSTOMUM

az Edges of anterior portion rolled in.

Z»! Anterior portion trough-shaped 2. HEMISTOMUM

62 Edges of anterior portion fused midventrally 3. STBIGEA

1. DlPLOSTOMTTM Nordmann. Body composed of 2 distinct portions ;
a large sucking disc back of the acetabulum: in the intestine of the
Crocodilia and of birds; intermediate hosts, fish; about 15 species.

D. grande Diesing. Oral sucker and acetabulum small; sucking
disc at the bottom of a deep cavity, the opening of which is on a conical

projection just back of the acetabulum;
length 4 mm. : in the intestine of the
snowy owl.

2. HEMISTOMUM Diesing. Anterior
portion of body flattened, the lateral
edges being prolonged medially, forming
a trough; behind the acetabulum and
sometimes projecting over it is an elon-
gated adhesive elevation: in the liver of
birds and mammals; about 15 species.

H. alatum (Goeze) (Fig. 309).
Length 6 mm.; acetabulum smaller than
the oral sucker, at each side of which
is a crescent-shaped opening of glands:
in the stomach and intestine of the fox
and dog.

3. STRIGEA Abildgaard (Holostomum Rudolphi). Lateral edges of
the forward portion of the body prolonged medially and joined mid-
ventrally, making this part of the body cup-shaped; behind the acetabu-
lum is a conical adhesive elevation in a deep cavity: in the intestine of
birds, rarely in fish and amphibians; about 30 species.

S. variegata (Dujardin) (Fig. 310). Conical elevation usually pro-
jecting from the cup; length 6 mm.; testes branched; genital bursa at
hinder end: in gulls, grebes, and loons.

Fig. 309

Fig. 310

Fig. 309 — Hemistomum alatum
(Brandes). a, adhesion elevation.
Other references as in Fig. 293.
Fig. 310 — Strigea variegata (Bran-
des). a, adhesion elevation; m,
mouth ; b, genital bursa ; c, cup-
shaped anterior end.

CESTODES 189

CLASS 3. CESTODES.* (TAPEWORMS.)

Soft, flat parasitic worms in which the body is made up of two
distinct parts, a head or scolex and a strobila. The scolex contains
either simple or complex suckers and often hooks, the organs of attach-
ment : the strobila is composed of a series of similar segments or proglot-
tids, each of which contains a complete set of male and female genital
organs. In the simplest cestodes, however, no segmentation of the body
occurs and but one set of genital organs is present (Fig. 312). The
cestodes are digenetic entoparasites which, with a few exceptions, live in
two different hosts; as 'adults they live in the intestine of a vertebrate as
final host, and as larvae in the muscles or some other compact tissues of
an intermediate host. The latter is some animal which is preyed upon or
occasionally eaten by the final host.

The scolex is without a mouth or organs of special sense. The suckers
are mostly 2 or 4 in number; their place is sometimes taken by variously
formed sucker-like projections called bothria (Fig. 319). Accessory
suckers (Fig. 318) are also sometimes present, and in a few forms the
entire scolex is absent or rudimentary and the anterior proglottids are
modified to form a so-called pseudoscolex, by means of which the animal
attaches itself. Hooks are often present on the scolex to assist the para-
site in maintaining its position. In the Tceniidae they are situated on a
central elevation called the rostellum, and in the Rhynchobothriidae on
four long retractile projections called proboscides.

Behind the scolex is usually a narrow unsegmented region called the
neck, after which come the proglottids or segments, which are derived by
a process of terminal budding from the scolex and may number from
three to several thousand in number, in the different species. The seg-
ments nearest the scolex are the youngest and smallest, those at the oppo-
site end of the strobila are the oldest and the largest. In Crossobothrium,
however, and probably also in other cestodes, a different and much more
complex method of growth has been observed,! new segments budding
towards the scolex as well as away from it. The genital organs are usually

* See "Die Parasiten des Menschen," etc., by R. Leuckart, 1879. "Cestodes,"
by M. Braun, Bronn's Klassen, etc., Bd. 4, p. 927, 1894 to 1900. "Tapeworms of
Poultry," C. W. Stiles, Bull. No. 12, Bureau An. Ind., 1896. "Parasites of Fishes
of the Woods Hole Region," by B. Linton, Bull. U. S. Fish. Com., Vol. 19, p. 405,
1900. "Die thierischen Parasiten des Menschen," by M. Braun, 1903. "Parasites
of Fishes of Beaufort," by B. Linton, Bull, of Bur. of Fish., Vol. 24, p. 321, 1905.
"Illustrated Key to the Cestode Parasites of Man," by C. W. Stiles, Bull. 25,
Hygienic Lab., Wash., 1906. "Taenoid Cestodes of North American Birds," by B. H.
Ransom, Bull. U. S. Nat. Mus., 1909. "Die Susswasserfauna Deutschl.," by M.
Liihe, 1910. "Index Catalogue," etc. "Cestoda and Cestodaria," by C. W. Stiles
and A. Hassall, Bull. 85, Hyg. Lab., Treas. Dep., 1912.

t See "The Formation of Proglottids in Crossobothrium laciniatum Linton," by
W. C. Curtis, Biol. Bull., Vol. II, p. 202, 1906.

190 PLATHELMINTHES

immature in the younger segments; those following contain the mature
organs, and in the terminal segments these have in most species degener-
ated, except the uterus, which is swollen with eggs, each of which usually
contains an embryo. In the typical human tapeworms these ripe seg-
ments are detached and pass out of the body of the host to the outside,
where they break open and the young are scattered. In the Bothrioceph-
aloidea, however, the eggs are laid in the intestine of the host and pass out
with the feces, the terminal segments often containing no eggs. In some
fish tapeworms the segments are detached before they are ripe and remain
free in the intestine. The outer surface of the body is an unciliated
cuticula, while the interior contains la vesicular parenchyma, in which
muscle fibers as well as the other internal organs and usually also cal-
careous concretions lie. No digestive system is present, nutrition being
carried on by absorption through the outer surface of the body. The
excretory system consists typically of two pairs of longitudinal canals,
one pair being near each lateral margin, which open to the outside in the
terminal segment. The two canals on each side are not of the same size,
the ventral being smaller than the dorsal and often disappearing alto-
gether. The dorsal and the ventral pair are very often connected by la
cross canal in each segment, and fine branches extend throughout the
parenchyma containing flame cells. The nervous system consists of a
number of longitudinal nerves extending the length of the body connected
in each segment by a ring commissure; in the scolex is a pair of large
ganglia forming the brain and usually other ganglia, joined with one
another by a complex system of commissures.

Cestodes, with rare exceptions, are hermaphroditic animals, each seg-
ment containing both male and female organs; in some species each seg-
ment contains two sets of genital organs, one on each side (Fig. 322).
The genital pores are situated either in the margin or in the ventral sur-
face of the segment. In the lowest cestodes there are three such pores,
through which the vas deferens, the vagina, and the uterus, respectively,
open to the outside (Fig. 315, B). In most cestodes the vas deferens and
vagina pass to a genital atrium which has a single external opening, and
no special uterine pore is present (Fig. 327, B). The arrangement of the
reproductive organs is complex and varies considerably in the different
groups of cestodes.

Habits and Distribution. — The typical embryo of the tapeworm is a
minute spherical animal called the onchosphere or six-hooked embryo (Fig.
311), which is provided with three pairs of locomotory hooks. Having
been swallowed by its first or intermediate host, either in drinking water
or on the food of the latter, it works its way by means of its hooks into
the blood vessels and may be carried with the blood to various parts of

CESTODES 191

the body of the host. It imbeds itself in a muscle or other organs and
develops into a characteristic larva called a bladder worm. This larva
is in some cases exactly like the scolex of the adult worm and is then
called a plerocercus. In other cases it con-
tains besides the scolex some or all of the
strobila, sometimes with the genital organs,
and is called a plerocercoid. In still others
it is an ovoid vesicle filled with a fluid and
containing one or more scolices and no
proglottids and is called a cysticercus, or S5SS^embTB«ie eg'g
a minute vesicle completely filled with an Retort)6. external '
invaginated scolex and called a cysticer-

coid. This larva remains quiescent in the intermediate host, but if
this animal be devoured by the final host the larva is transferred to the
intestine of the latter and, at once attaching itself to the intestinal wall,
begins to produce the strobila. In a few weeks or months the entire worm
is usually formed.

Cestodes are among the most pronounced animal parasites and are
found in all countries and in all of the larger animals. Man and his
domestic animals are especially liable to infection and may be the hosts
of some very dangerous tapeworms.

History.— The common tapeworms of man, including both the adult
and the larval worm, have been known to science from the time of the
Greeks. The name Tcenia for a tapeworm occurs in Pliny, and the name
Ttznia solium has been employed since the Middle Ages, when it was given
to all the common tapeworms. The order Cestodes was established in 1808
by Rudolphi. It included however only the adult worms, the larval worms
being placed by Rudolphi in the separate order Cystici. The relation of
the adult to the larval worms was not then understood, notwithstanding
the fact that Goeze and Pallas in the previous century had both clearly
indicated it, Rudolphi and all the important helminthologists of his time
believing that tapeworms may develop by spontaneous generation in the
places where they are found. In fact it was not until 1851 that it was
finally demonstrated by Kiichenmeister that the bladder worm is the larval
stage of the adult worm. This investigator showed that if Cysticercus
pisiformis be fed to a dog Tcenia serrata will very shortly appear in the
dog's intestine. He and others afterwards repeated the experiment with
the tapeworms of the cat and of man and of other animals. In the case
of the human tapeworms the cysticerci were given to condemned criminals
and the adult worms were invariably found in their intestines after
death. Rudolf Leuckart has since been the most active in the study of the
entire group.

192

PLATHELMINTHES

The class contains not far from 1,000 species, which are distributed
among 2 subclasses.

Key to the subclasses of Cestodes:

di No scolex ; no segmentation ; embryo with 10 hooks 1. CESTODARIA.

a. Body usually segmented and with a scolex ; embryo with 6 hooks.

2. CESTODES, a. str.

SUBCLASS 1. CESTODAKIA.

Small, unsegmented worms which live in fishes as adults and in
mollusks and annelids as larvae; no distinct scolex is present although the
forward end has a contractile papilla or a sucker ; but 1 set of genital organs
present ; uterus a winding tube with an external opening ; embryo with 10
locomotory hooks and called a lycophora: 2 genera and about 4 species.
1. GYROCOTYLE* Diesing (Fig. 312). Body leaf-like and elliptical,
.with fluted margins ; a small sucker at one end and a peculiar ' ' rosette ' '
organ at the other end with a retractile proboscis: 4
species.

G. fimbriata Watson. Length up to 55 mm. ; width
10 mm.; in intestines of Chimera; California.

2. AMPHILINA Wagener. Body flat and leaf-like:
forward end with a small sucker, beside which is the
uterine pore; at the opposite end are the openings of
the cirrus and the vagina: 2 species.

A. foliacea (Rudolphi). Length 20 mm.: in the
body cavity of sturgeons.

Fig. 312

Diagram of

Oyrocotyle

(Spencer from

Watson).
1, sucker ; 2, male
genital pore ; 3,
vagina*; 4, uter-
ine pore; 5,
nerve ; 6, uterus ;
7, yolk duct ; 8,
rosette.

SUBCLASS 2. CESTODES— Sensu stricto.

Body, except in rare cases, segmented, with a
scolex, which, however, may be rudimentary or re-
placed by a pseudoscolex ; uterus with an external
opening only in the Bothriocephaloidea; vas deferens
and vagina open usually into a genital cloaca which
opens to the outside by a single pore: 5 orders and
about 90 genera.

Key to the orders of Cestodes here described :

Oj Uterine pore present ; genital organs do not degenerate in the ripe seg-
ments 1. BOTHBIOCEPHALOIDEA

c2 No uterine pore ; ripe segments contain the gravid uterus and little else.
&! Proboscides not present in scolex.
G! Four bothria usually present ; yolk glands paired ; principally in fishes.

2. TETRAPHYLLIDEA
c2 Four suckers present ; yolk glands not paired ; in land vertebrates.

3. CYCLOPHYLLIDEA.
62 Four retractile proboscides present in scolex ; in fishes . 4. TRYPANORHYNCHA.

* See "The Genus Gyrocotyle," etc., by E. E. Watson, Univ. of Cal. Pub., Vol. 6,
p. 353, 1911.

CESTODES 193

ORDER 1. BOTHRIOCEPHALOIDEA.

Body often long, with or without distinct segmentation; scolex with
2 suckers, one in the dorsal and one in the ventral surface, which are
usually weak and in certain forms are highly modified by the extension of
their edges, and may be rudimentary or wanting, when their place may
be taken by a single accessory sucker or 'a pseudoscolex ; a uterine or
birth pore present in the ventral surface; the other two genital pores
also usually ventral but may be dorsal or marginal; testes numerous;
ovary either distinctly or indistinctly paired and in the hinder part of
the segment ; yolk glands paired in the lateral areas of the segment ; the
genital organs do not degenerate: about 4 families; either adult or larval
form usually in fishes.

Key to the families of Bothriocephaloidea here described:

01 Uterus an irregularly coiled tube 1. DIPHYLLOBOTHRIIDAE

oa Uterus not a coiled tube, usually sac-like 2. PTYCHOBOTHRIIDAE

FAMILY 1. DIPHYLLOBOTHEIIDAE.

Scolex usually without hooks, segmentation in most cases distinct,
but sometimes wanting; cirrus (penis) without spines; uterus a long tube
coiled back and forth across the segment: 4 subfamilies and about 15
genera.

Key to the subfamilies of Diphylloboihriidae here described:

Ox Two suckers present.

&! Scolex very short ; no neck present 1. LIGULINAE

62 Scolex elongate ; neck usually present 2. DIPHYLLOBOTHRIINAE

02 But 1 sucker 3. CYATHOCEPHALINAE

SUBFAMILY 1. LIGULINAE.

Scolex short, triangular, with small suckers and without hooks ; genital
pores ventral : in the intestine of water birds as adults ; larva a plerocer-
coid which may be as large as the adult and is found free
in the body cavity of fishes : 2 genera.

1. LIGULA Bloch. Suckers and external segmentation
wanting in the larva, and only the forward portion exter-
nally segmented in the adult, these segments, however, not
corresponding to the internal segmentation: 1 species.

L. intestinalis (L.) (Fig. 313). Length up to 40 cm. or
more ; width 10 mm. : in perch, pike, and other fresh-water
fish as a larva, and in gulls and other water birds as
adult.

2. SCHISTOCEPHALTTS Creplin. Suckers and external segmentation
present and distinct in the larva as well as the adult, and internal and
external segmentation identical: 1 species.

194

PLATHELMINTHES

Fig. 314 — Schistocephalus gasterostei. A, forward

end (Linton) ; B, fish containing the larval

worm (Cambridge Natural History).

S. gasterostei (Fabricius) (Fig. 314). Length up to 30 cm.i in
Gasterosteus and other fish and also the frog as a larva, and in water birds
as adult.

SUBFAMILY 2. DIPHYLLOBOTHBIINAE.

Scolex without hooks and with either 2 small suckers or highly modi-
fied suckers; segmentation distinct; cirrus and vagina open into a

genital cloaca, the pore of
which is ventral and in
front of the uterine pore:
6 genera; in higher verte-
brates.

1. DlPHYLLOBOTHRIUM

Cobbold (Bothriocephalus
Rudolphi; Dibothriocepha-

lus Liihe). Scolex flattened laterally with 2 deep slit-like suckers; strobila

long; uterus a long tube coiled zigzag: over 50 species; in carnivorous

mammals and water birds.

D.. latum (L.) (Fig. 315).

Length up to 9 m., with several

thousand segments; onchosphere

ciliated and free-swimming: larva a

plerocercoid 30 mm. long found in

the perch and many other fishes;

adult worm in man, also in the cat
and dog, and com-
mon in certain locali-
ties, especially where
fish is much eaten;
in this country rare.

SUBFAMILY 3. CYATHOCEPHALINAE.

Scolex usually with a single terminal sucker; outer
segmentation indistinct or wanting; genital pores either
ventral or dorsal or both: 1 genus.

CYATHOCEPHALTJS Kessler. With the characters of
the subfamily: 1 species.

0. tnmcatus (Pallas) (Fig. 316). Length up to 20
mm.; with about 6 segments: in the pyloric coeca of the
whitefish.

FAMILY 2. PTYCHOBOTHEIIDAE.

Scolex without hooks, with 2 suckers more or less developed, each
of which may be converted into a pocket by the partial fusion of its

Fig. 315 — Diphyllobothrium latum
(Leuckart). A, anterior end, showing
suckers ; B, mature segment. 1, yolk
gland ; 2, birth pore ; 3, uterus ; 4,
ovary ; 5, excretory canal ; 6, nerve ;
7, testes ; 8, vaginal pore ; 9, male geni-
tal pore (cirrus) ; 10, uterine pore.

Fig. 316

Cyatho-

cephalus

truncatus

(Zschokke).

CESTODES 195

walls, or may be subdivided into 2 portions, of which the hinder may have
the appearance of a separate sucker; a pseudoscolex may also take the
place of the scolex; uterus usually an extensive sac, which may occupy
the greater part of the segment with a ventral opening; pore for cirrus
and vagina either marginal or dorsal: 7 genera; in fishes.

1. ABOTHRITJM van Beneden. Suckers shallow; a cylindrical pseudo-
scolex may be present in place of the scolex, the hinder margin of
which is prolonged backwards so as to project over the strobila; seg-
mentation of hinder part indistinct; cirrus and vaginal pores marginal,
that of uterus medium: 3 species.

A. rugosum (Batsch). Length 25 cm. or more; breadth 4.7 mm.:
in the intestine of the cod; often common.

2. BOTHRIOCEPHALUS Rudolphi (Dibothrium Diesing). Scolex elon-
gate with rather weak suckers; no accessory suckers; segmentation
often indistinct; neck not present; uterine opening mid ventral; common
genital pore for cirrus and vagina middorsal: about 4 species.

B. lacinatus (Linton). Body 15 cm. long, 4 mm. broad in the
middle, tapering towards hinder end ; segmentation distinct, the posterior
margins of the proglottids projecting backwards, making the margin of
the strobila serrate : in Tarpon atlanticus.

ORDER 2. TETRAPHYLLIDEA.

Scolex with 4 bothria, which vary much in form, being either stalked
or not and with or without hooks and accessory suckers; a pseudoscolex
may replace the scolex; segmentation distinct; cirrus and vagina open on
the margin; no uterine pore; yolk glands paired: 4 families and about
30 genera; in selachians, and also in other fish, amphibians, and reptiles.

Key to the families of Tetraphyllidea here described:

«! Hooks present at the forward end of each bothrium .... 1. ONCHOBOTHBIIDAE
az No such hooks 2. PHYLLOBOTHRIIDAE

FAMILY 1. ONCHOBOTHEIIDAE.

Hooks of various shape present in the anterior rim of the bothria;
bothria either sessile or with short stalks; accessory suckers usually
present ; the segments usually detach themselves before sexual maturity :
in spiral valve of selachians; 9 genera.

1. CALLIOBOTHRITJM van Beneden. Bothria elongate, each being
divided by 2 transverse septa into 3 divisions of unequal size and with
either 1 or 3 small accessory suckers and 2 or 4 simple hooks: several
species.

C. verticillatum (Rudolphi). Length up to 15 cm.; length of ter-
minal segment about 3.5 mm., width 1.7 nun. ; a 3-lobed accessory sucker
and 4 hooks in front of each bothrium; body very slender, resembling

196

PLATHELMINTHES

a white hair ; scolex the size of a small pinhead : often common in spiral
valve of the smooth dogfish.

2. PHOREIOBOTHRIUM Linton. Bothria rectangular and elongate,
without subdivisions; an accessory sucker and 2 three-pronged hooks
at the forward end of each bothrium; neck long, with
minute spines: 1 species.

P. lasium Linton (Fig. 317). Length 4 cm.; terminal
segment about 2.2 mm. long and .84 mm. wide: in spiral
valve of the dusky shark.

FAMILY 2. PHYLLOBOTHEIIDAE.

Fig. 317

Scolex of

Phoreioboth-

rium lasium

(Linton).

Scolex without hooks; bothria usually stalked and with
or without septa subdividing them, and with or without a
myzorhynchus, which is a central, stalked sucker rising
from midst of the bothria, and other accessory suckers: about 12 genera.
Key to the genera of Phyllobothriidae here described:

a* Bothria without transverse septa and myzorhynchus.

&! Bothria without accessory suckers 1. ANTHOBOTHEIUM

&2 Bothria with accessory suckers.

Ci Each bothrium with 2 suckers 2. OEYGMATOBOTHEIUM

C2 Each bothrium with 1 sucker.

d^ Edges of bothria not or but little convoluted 3. CBOSSOBOTHBIUM

dz Edges of bothria very much convoluted 4. PHYLLOBOTHRIUM

a, Bothria with 2 septa and with a myzorhynchus 5. ECHENEIBOTHBIUM

1. ANTHOBOTHRIUM van Beneden. Bothria very contractile, oval
in shape, stalked, their edges not or but little folded; without accessory
suckers; body elongate: several species.

A. laciniatum Linton. Length up to 21 mm.; length of terminal
segment about 1.8 mm., width 1 mm. : in spiral valve of
sand shark and other sharks; often numerous.

2. ORYGMATOBOTHRITJM Diesing. Bothria stalked,
with a larger accessory sucker in the middle and a
smaller one at the forward end of each, which may be
confluent; neck long: several species.

0. paulum Linton. Length 9 mm.; breadth of ter- *
minal segment about .28 mm., length 1.03 mm.: in spiral valve of the
tiger shark; often very numerous.

3. CROSSOBOTHRITJM Linton. Bothria stalked, each with an acces-
sory sucker at the forward end, and with its rim more or less convo-
luted; body elongate: 1 species.

C. laciniatum Linton (Fig. 318). Length up to 25 cm.; segmenta-
tion occurs at certain times in both directions, making the middle segments
the youngest : in the spiral valve of the sand shark ; common.

Fig. 318

Crossobothrium

laciniatum

(Curtis).

CESTODES 197

4. PHYLLOBOTHRITJM van Beneden. Bothria sessile or nearly so,
with very convoluted edges and with an anterior accessory sucker; neck
very long: several species.

P. f oliatum Linton. Length up to 18 cm. ; length of
terminal segment about 1.4 mm., width .9 mm.: often
numerous in spiral valve of the sting ray.

5. ECHENEIBOTHRIUM van Beneden. Bothria stalked,
elongate or oval, and very contractile, the face of each

Fig. 319

being subdivided by 1 or 2 longitudinal and several trans- Scolex of

Echeneibothriuw,

verse septa; myzorhynchus present but may be wanting in vaHdbUe
. (Braun).

old worms: several species.

E. variabile v. Ben. (Fig. 319). Length about 10 cm.; neck long:
in the spiral valve of the common skate; often common.

ORDER 3. CYCLOPHYLLIDEA.

Body usually elongate; scolex with 4 simple cup-shaped suckers,
between which a protrusile rostellum with hooks is usually present;
segmentation distinct; no uterine pore; common genital pore usually
marginal; yolk gland unpaired and usually behind the paired ovary: 10
families and about 50 genera which live principally in the higher verte-
brates; larva a cysticercus or cysticercoid, so far as known.

Key to the families of Cyclophyllidea here described:

di Uterus transverse in position and either tubular, sac-like, or reticulate.

&x Scolex without hooks 1. ANOPLOCEPHALIDAE

&2 Scolex with hooks.

cv No hooks in the suckers 2. DIPYLIDIIDAE

c2 Suckers armed with hooks 3. DAVAINEIDAE

a2 Uterus consists of a median stem and side branches 4. T^ENIIDAE

FAMILY 1. ANOPLOCEPHALIDAE.*

Scolex more or less spherical, without hooks but with large suckers;
segments short and wide; uterus transverse in position and tubular, sac-
like, or reticular: in mammals; 8 genera.

Key to tKe genera of Anoplocephalidae here described :

<H Genital pore on but one side of the segment.

&! Genital pores on the same side of all the segments 1. AXOPLOCEPHALA

&2 Genital pores regularly or irregularly alternate 2. BERTIA

a2 Genital pores on both sides of the segment.

&! Uterus reticulate and double 4. MONIEZIA

&2 Uterus tubular.

G! Uterus a thick tube, single or double : in rodents 3. CITTOT^ENIA

cs Uterus undulate : in sheep 5. THYSANOSOMA

* See "A Revision of the Adult Tapeworms of Hares and Rabbits," by C. W.
Stiles, Proc. U. S. Nat. Mus., Vol. 19, p. 145, 1896.

198

PLATHELMINTHES

1. ANOPLOCEPHALA Blanchard. Segments much broader than long;
genital pores all on the same side of the segments and never on both
sides: about 16 species; in horses and rodents.

A. perfoliata (Goeze) (Fig. 320). Length up to 8
cm. ; scolex large, square, with 4 projections extending
backwards, 2 being dorsal and 2 ventral: in the ileum,
caecum, and colon of the horse, often in large numbers.
2. BERTIA Blanchard. Segments broader than
rio^fnd^lno11*? lon£> genital pores regularly or irregularly alternate,

cephaia perfoliata j^ never on both sides of a segment: in apes, mon-
( Ward).

keys, and rodents; about 6 species.

B. americana (Stiles). Length 33 mm.; width 6 mm.; with about
90 segments; no calcareous concretions: in porcupines; often common.

3. CITTOT^INIA* Riehm. Segments
broader than long with genital pores on
both sides ; 2 sets of genital organs and 1 or
in some cases 2 simple, transverse, tubular
uteri in each segment; vagina always ven-
tral to the cirrus: in rodents; 7 species.

C. variabilis (Stiles) (Fig. 321).
Length up to 18 cm.; breadth 10 mm.;
cirrus pouch tubular, of equal diameter
throughout; testes form a band in the
median area between the ovaries: in the
cotton-tail rabbit and the marsh hare.

4. MONIEZIAJ Blanchard. Segments broader than long with genital
pores on both sides; 2 sets of genital organs and 2 complex reticulate
uteri in each segment; vagina ventral on right side and dorsal on left
side to cirrus; interproglottidal glands along hinder

margin of the segment: 6 species; in ruminants.

Fig. 321 — Cittotcenia variaUlia
(Stiles). A, head; B, a seg-
ment. 1, excretory canals ; 2,
ovary ; 3, testes.

Fig. 322 — Moniezia pianissimo. (Stiles). A, a segment; B, head. 1, genital pore;
2, ovary ; 3, yolk gland ; 4, interproglottidal gland.

M. planissima Stiles and Hassall (Fig. 322). Body very broad and
flat and up to 2 m. long, and 26 mm. broad; interproglottidal glands

* See "Studies on the Genus Cittotsenia," by R. A. Lyman, Stud, from Zool.
Lab., Univ. of Neb., No. 48, 1902.

t See "A Revision of the Adult Cestodes of Cattle, Sheep," etc., by C. W. Stiles
and A. Hassall, Bull. No. 4, Bur. Animal Ind., 1893.

CESTODES

199

elongate and not in groups : in small intestine of sheep and cattle ; often
common.

M. expansa (Rudolphi) (Fig. 323). Body up to 4 m. long and 26
mm. wide, and often
quite thick ; interpro-
glottidal glands a
straight row of round
sacs : in sheep, cattle,
deer, and goats ; com-
mon.

5. THYSANOSOMA

Diesing. Segments broader than long with genital pores on both sides or
only on one side, and either 2 or 1 set of genital organs; a single uterus

in each segment con-
sisting of an undulat-
ing, transverse tube
with side pockets: 2
species, in sheep.
T. actinoides Dies.

Fig. 323 — Moniezia expanse, (Stiles). A, two segments;
B, end view of head ; g., interproglottidal glands.

Fig. 324 — Thysanosoma actinoides (Stiles). A, head,
side view and ventral view ; B, segments.

A

The fringed tapeworm
(Fig. 324). Length

up to 30 cm.; width 8 mm.; head prominent; neck very flat and broad;

hinder margin of each segment fringed : common in the west.

FAMILY 2. DIPYLIDIIDAE.

Scolex usually with hooks on a rostellum; uterus made
up of a large number of egg sacs, or it may be absent, in
which case the eggs are distributed throughout the par-
enchyma; larva a cysticercoid: in birds, mammals, and
reptiles; 10 genera.

1. DIPYLIDIUM Leuckart. Rostellum retractile and
with hooks; genital pores and organs double in each seg-
ment; uterus reticular: 1 species.

D. caninum (L.) (D. cucumerinum Rudolphi) (Fig.
325). Length up to 25 cm.; breadth 3 mm.; ripe segments
about 7 mm. long and 3 mm. wide and often reddish in
color : in cats and dogs, and occasionally in young children ;
cysticercoid in the dog's flea; common.

2. HYMENOLEPIS* Weinland. Small filiform worms with broad seg-
ments with the genital pores all on the left and never on both sides;

* See "An Account of the Tapeworms of the Genus Hymenolepis Parasitic in
Man," by B. H. Ransom, Bull. No. 18, Hyg. Lab., 1904.

Fig. 325
Dipylidium

caninum
(from Ward).

200

PLATHELMINTHES

rostellum retractile and with or without hooks; 3 testes in each seg-
ment ; with a sac-like uterus filling the ripe segment : 'about 30 species ; in
mammals and birds.

H. n?,na (von Siebold). The dwarf tapeworm (Fig. 326). Length
15 mm. or more; breadth .7 mm.; scojex with a single row of about 28
hooks: in the small intestine of man and the rat and
mouse; the cysticercoid lives in the intestinal villi of the
same host; the parasite often causes diarrhea and nervous
attacks.

H. carioca (Magalhaes). Length up to 8 cm.; width
.7 mm.; rostellum without hooks; edge of strobila serrate:
in chickens; common.

H. dimnuta (Rudolphi). Length up to 6 cm.; width
4 mm.; rostellum rudimentary, without hooks: in cats and
mice.

FAMILY 3. DAVAINEIDAE.

Scolex with hooks on a retractile rostellum and
numerous small hooks in the suckers; genital pore usually
on on^ one s^e °^ a se^men^ : 3 genera; in mammals and
birds.

DAVAINEA Blanchard and Railliet. Small worms; eggs in capsules
in the middle area of the ripe segment: about 15 species.

D. salmoni Stiles. Length 88 mm.; breadth 3 mm.; number of seg-
ments about 450 ; genital pores generally alternate : in Lepus sylvaticus and
L. melanotis.

FAMILY 4. T^ENIIDAE.

Scolex usually with a rostellum with hooks; uterus, in the ripe seg-
ment, composed of a median tube and lateral branches; usually long
worms with segments longer than wide; genital pores alternating irregu-
larly and never on both sides of a segment : several genera.

1. TJENIA L. With the characters of the family : numerous species,
which are usually found in predacious mammals and man, the cysticer-
cus being found in ruminants and other plant feeders.

T. saginata Goeze. The beef tapeworm (Fig. 327). Length 10 m.
or more, with over a thousand segments, usual length 4 to 8 m. ; ter-
minal segments about 20 mm. long and 7 mm. broad, containing a uterus
which has from 20 to 30 branches on each side; scolex 2 mm. thick,
without rostellum or hooks: in the human intestine; the cysticercus
(C. bovis) is about 9 mm. long and 5 mm. thick and lives in the muscles of
cattle, and a person may infect himself with the worm by eating rare
beef; the commonest human tapeworm in this country.

CESTODES

201

T. solium L. The pork tapeworm (Fig. 328). Length about 3 m.,
with about 900 segments; terminal segment about 12 mm. long and

Fig. 327 — Tcenia saginata (Leuckart). A, head with the anterior segments ; B, a
segment about a third of the distance back from the head ; C, terminal segment ;
D, a piece of beef containing three cysticerci ; P, common genital pore. Other refer-
ences as in Fig. 315.

6 mm. wide, containing a uterus which has from 7 to 10 branches on
each side; scolex about 1 mm. thick with a rostellum bearing a double
row of about 28 hooks: in the human intestine; the cysti-
cercus (C. cellulosae) is from 6 to 20 mm. long and about
half as wide and thick and lives normally in the muscles of
the pig, but also lives readily in man, being found in the
eye, brain, heart, and other organs and causing often in-
sanity or death; rare in this country.

T. marginata Batsch. The large dog tapeworm.
Length up to 3 m. ; terminal segments 10 mm. long and
5 mm. wide, containing a uterus with from 4 to 8 branches
on each side; rostellum with 2 rows of about 38 hooks: in
the dog; cysticercus (C. tenuicollis] in the viscera of pigs
and ruminants; not common in this country.

T. serrata Goeze. The serrate dog tapeworm. Length
up to 1 m. ; terminal segments 10 mm. long and 5 mm. wide,
containing a uterus with 8 to 12 branches on each side ; edge
of strobila serrated; rostellum with 2 rows of about 40
hooks: in the dog; cysticercus (C. pisiformis) about the
size of a small pea, in the peritoneum of rabbits and hares ;
common.

T. crassicollis Rudolphi. The cat tapeworm. Length
up to 60 cm. ; terminal segments 10 mm. long and 6 mm. wide, containing
a uterus with about 10 branches on each side; rostellum with 2 rows of

Fig. 328

Tcenia solium

(Leuckart).

A, head
B, terminal

segment.

202

PLATHELMINTHES

Fig. 329 — Multi-
ceps multiceps

(Ransom),
ripe segment.

about 50 hooks: in the cat; cysticereus (C. fasciolaris) in the liver of the
mouse and rat, where it forms a conspicuous tumor, and is peculiar in that
it consists of a scolex and a number of segments, the
latter, however, degenerating on arriving in the cat's
intestine and the scolex developing a new strobila; very
common.

2. MULTICEPS Goeze. Like Tcenia but with a large
cysticereus from the inner wall of which many scolices
project into the interior: about 6 species.

M. multiceps (Leske) (Tcenia ccenurus von Sie-
bold). The gid tapeworm* (Fig. 329). Length up to
60 cm. ; terminal segments 5 mm. long and 2 mm. broad,
containing a uterus with about 22 branches on each side ;
rostellum with 2 rows of about 30 hooks: in the dog;
cysticereus (Caenurus cerebralis), which is 25 mm. in
diameter or larger and spherical and
contains hundreds of scolices, lives in
the brain or spinal cord of sheep and
occasionally cattle, causing gid or stag-
gers; northwestern states; Europe; often killing great
number of sheep.

3. ECHINOCOCCUS Rudolphi. Like Tcenia, but with
a large cysticereus from the inner wall of which capsules
of scolices project into the interior: several species.

E. granulosus (Batsch) (Tcenia echinococcus von
Siebold). The echinococcus tapeworm (Fig. 330).
Length up to 5 mm., with but 3 -or 4 segments; rostellum
prominent, with 2 rows of about 40 hooks: in the dog;
cysticereus (Echinococcus polymorphus) lives in the
liver or other organs of sheep, pigs, cattle, or other
animals, and also in man, when it is called a hydatid
cyst, and as it may grow to be half a foot in diameter
and to weigh several- pounds and contains thousands of
scolices, it may cause death; often common in Europe
but apparently rare in this country; infection obtained directly from the
hair or tongue of dogs.

ORDER 4. TRYPANORHYNCHA.

Scolex very long, composed of 2 portions, a head which has 2 or 4
bothria and 4 retractile and spinose proboscides, and a long head stalk;

Fig. 330

Echinococcus

granulosua

(Braun).

* See "The Gid Parasite," etc., by B. H. Ransom, Bull. 66, Bur. An. Ind., U. S.
Dept. Ag., 1905. "The Gid Parasite," etc., by M. C. Hall, Bull. 125, ditto, 1910.

NEMEETEA

203

segmentation distinct; genital pores marginal; genital organs with the
same arrangement as in the Tetraphyllidea : in the intestine of selachians;
larvae encysted in teleosts; 2 families.

FAMILY EHYNCHOBOTHKIIDAE.
With the characters of the orders: numerous genera,
concerning the value and position of many of which much
uncertainty prevails.

1. RHYNCHOBOTHRIUS Rudolphi. Two bothria, one
dorsal and one ventral, which tend to converge at their
forward ends: many species.

R. bulbifer Linton (Fig. 331). Bothria oval; neck
long and slender; length of body up to 40 mm., with 12 or
less segments: in spiral valve of Mustelus cams; cysts in
mackerel, bluefish, and other teleosts; common.

2. TETRARHYNCHOBOTHRIUM Diesing. Four bothria
present; head stalk cylindrical; many species.

T. robustmn (Linton). Bothria elongate; length of
body 24 mm.; segments usually broader than long: in
stomach and intestine of skate; common.

Fig. 331

Rhyncho'bot'hf

rius bulbifer

(Linton).

CLASS 4. NEMERTEA.5

Nemerteans.

Soft, very contractile, and often brightly colored flat-
worms, most of which are non-parasitic
and live in the sea. The body is usually
elongate and more or less tape-like or fili-
form, varying in length from 5 mm. to
30 m. in the different species; it is unseg-
mented, but often has an annulated ap-
pearance due to the regularly repeated
subdivisions of certain of the internal
organs. The mouth is in the ventral sur-
face near the front end and the anus is at
the hinder end of the body. Dorsal to the mouth (Fig. 332) is an opening
into a very deep tubular pocket, extending far back into the body, a portion

* See "Marine Nemerteans of New England and Adjacent Waters," by A. E.
Verrill, Trans. Conn. Acad., Vol. 8, p.. 382, 1892. "Die Nemertinen," Fauna u. Flora
d. Golfes v. Neapel, by O. Burger, 1895. "Nemertini," Kl. u. Ordn., Vol. 4, Supp.,
1897. "On the Connective Tissues and Body Cavities of the Nemerteans, with Notes
on Classification," by T. H. Montgomery, Jr., Zool. Jahrb. Anat, Vol. 10, p. 1. "Notes
of the Times of Breeding of Some Common New England Nemerteans," by W. R. Coe,
Science N. S., Vol. 9, p. 167, 1899. "Nemertini," by O. Burger, Das Tierreich, 1904.
"Synopsis of the Nemerteans, Part I," by W. R. Coe, Am. Nat., Vol. 39, p. 425.
"Nemerteans of the West and Northwest Coast of North America," by W. R. Coe,
Bull. Mus. Comp. Zool., Vol. 47, 1905.

Fig. 332 — Diagram of nemertean
worm — lateral aspect (Biirger).
1, proboscis pore ; 2, ventral gan-
glion ; 3, mouth ; 4, dorsal gangli-
on ; 5, dorsal nerve ; fi, intestine ;
7, proboscis ; 8, proboscis sheath.

204

PLATHELMINTHES

of which can be everted and thrust forward in the form of a proboscis
(Fig. 333) : in most hoplonemerteans this opening coincides with the
mouth. The proboscis is often nearly as long as the body itself and can
be thrust out far in advance. It is primarily a tactile organ and in the
hoplonemerteans is armed with calcareous stylets of characteristic form,
indicating that it has also an offensive function. Dorsal to the proboscis
in most species are the openings of the so-called cephalic glands. In
Malacobdella a large sucker is present at the hinder end, and Nectonemertes
possesses a pair of lateral swimming
organs. Many heteronemerteans have
a caudal cirrus at the posterior end.
The outer surface of the body is a
glandular, ciliated epithelium and is
often brightly colored.

No body cavity is present, the
spaces between the organs being filled
with a gelatinous parenchyma. The
proboscis, however, is surrounded by a
muscular sheath containing a corpuscu-
lated fluid (Fig. 333,4). The digestive
canal extends the whole length of the
body, and is usually differentiated into
oesophagus, stomach, intestine, and rec-
tum. The intestine is often provided
with regularly recurring paired diver-
ticula and in the hoplonemerteans has
a long intestinal caecum, extending for-
ward to near the front end of the body.
Two or three longitudinal blood vessels
with connecting branches and contain-
ing a corpusculated fluid differing
somewhat from that in the proboscis

sheath extend the length of the body and are connected with large blood
spaces. A pair of profusely branched longitudinal excretory canals lie
alongside the lateral blood vessels in the anterior portion of the animal,
which usually open to the outside through one or more pores on each side
of the body. Minute branches of these canals extend into the parenchyma
and end in flame cells. The central nervous system consists of a four-
lobed brain and a pair of large lateral nerves (Fig. 332) extending to
the hinder end of the body, where they join; a dorsal median nerve is
also usually present and in some species a ventral median one as well.
A pair of lateral ciliated canals called the cerebral organs because they

Fig. 333 — Diagram of nemertean
worm — dorsal aspect. A, with pro-
boscis retracted ; B, with proboscis
extended (altered from Boas). 1,
stylet; 2, proboscis; 3, poison
gland ; 4, proboscis sheath ; 5, in-
testine ; 6, gonads.

NEMEETEA 205

lie in close relation to the dorsal cerebral lobes occur in most nemer-
teans: these are represented by a pair of lateral sensory grooves in
many paleonemerteans. In the hoplonemerteans and some heteronemer-
teans also occur one to three supraoral or frontal organs, which are
sensitive protuberances capable of being retracted so as to form a pit.
Simple ocelli, each with lens and nerve, occur in most nemerteans.
The number of such ocelli, which in a few forms are scattered along the
sides of the body, may exceed 200. A few species have auditory sacs.
The muscular system is well developed, consisting of two or three layers
of circular and longitudinal muscles which bear an intimate relation to
the main nerves.

Most nemerteans are unisexual, but a few are hermaphroditic. The
gonads are paired, spherical organs, which usually lie between the intes-
tinal diverticula (Fig. 333) and discharge their products directly through
the body wall to the outside, no permanent genital ducts being present.
A few are viviparous. Development is direct in many forms, while in
others the young animal leaves the egg as a free-swimming larva
(pilidium or Desor's larva) and passes through a complicated metamor-
phosis before acquiring the form of the parent.

History. — The Nemertea have only quite recently been given an inde-
pendent systematic position, having been formally grouped with the
Turbellaria. The name originated with Cuvier, who in 1815 gave the ge-
neric name N emeries to Linens longissimus. Johnston (1846) first employed
the name for the entire group. At the present time it is a matter of dis-
pute whether the Nemertea should be grouped with the PlatJielmintJies or
be given an independent position. The modern classification is due princi-
pally to Hubrecht and Burger. The class contains over 400 species
grouped in 4 orders, 87 species having been found on our Pacific and 62
species on our Atlantic coast.

Key to the orders of Nemertea:

Oi No sucking disc present ; intestine not convoluted.

&! Proboscis without stylets ; mouth behind brain ; intestinal caecum absent.
cx Muscular walls of body usually in 2 layers ; eyes usually absent.

1. PALEONEMEBTEA
ca Muscular walls of body in 3 main layers ; eyes usually present.

2. HETEBONEMEBTEA
52 Stylets usually present ; mouth in front of brain ; intestinal caecum

usually present 3. HOPLONEMEBTEA

a, Sucking disc present ; intestine convoluted 4. BDELLONEMEBTEA

ORDER 1. PALEONEMERTEA. (PROTONEHERTINI; MESONEMERTINI.)

Body long and slender, often filiform ; mouth usually far back, being
always behind the brain; proboscis without stylets; cerebral organ and
eyes usually absent; body wall contains two muscle layers, an outer

206 PLATHELMINTHES

circular, an inner longitudinal, to which a third, an inner circular, is
sometimes added; lateral nerves either external to the muscles or
imbedded in the longitudinal layer; cutis absent: 4 families, all marine.
Key to the families of Paleonemertea here described:

Oj Paired intestinal diverticula absent 1. CABINELLIDAE

o2 Paired intestinal diverticula present 2. CEPHALOTBICHIDAE

FAMILY 1. CABINELLIDAE.

Cerebral organs represented by a pair of lateral epithelial depres-
sions; brain and lateral nerves lie in the outer epithelium or just
beneath it ; mid-dorsal blood vessel usually absent ; inner circular muscles
encircling the proboscis sheath and intestine very thick: 5 genera and
about 27 species.

CARINELLA Johnston. Body cylindrical and filiform, with the head
end large and distinctly set off; intestinal diverticula absent; lateral
sense organs usually present near the paired excretory pores, consisting
each of a round ciliated depression : 16 species, principally on the Pacific
coast.

C. pellucida* Coe. Body very small, whitish in color, up to 25 mm.
long and .5 mm. thick: not uncommon among annelid tubes at low water
and below in Long Island and Vineyard Sounds; California.

FAMILY 2. CEPHALOTRICHIDAE.

Body long and very slender, usually filiform; cerebral organ and
eyes usually absent; mouth behind the brain; body wall contains two
muscle layers, an outer circular and an inner longitudinal, with the brain
and longitudinal nerves lying in the latter layer: 2
genera and about 12 species.

1. CEPHALOTHRIX Oersted. Body filiform, taper-
ing at the forward end, which is pointed; no excre-
tory canals; inner circular muscles absent; the worm
coils the body in a spiral: about 7 species.
IB C. linearis (Rathke) (Fig. 334). Body whitish,
yellowish, or flesh color, up to 15 cm. long and 1 mm.
thick; mouth very far back; proboscis very long and
slender: Long Island Sound to Nova Scotia; Pacific
coast; Europe; often common between tide lines, under stones and in
the sand; breeds in August at Woods Hole.

2. CARINOMA Oudemans. Body rather thick, cylindrical in front,
flattened behind: 4 species.

* See "Descriptions of Three New Species of New England Paleonemerteans,"
by W. R. Coe, Trans. Conn. Acad., Vol. 9, p. 515, 1895.

NEMEETEA

207

C. tremaphoros C. B. Thompson. Body 12 cm. long, 3 mm. thick,
buff in color; head white, flattened, rounded in front: Woods Hole.

ORDER 2. EETERONEMERTEA. (SCHIZONEMERTEA.)

Body often very long; mouth behind brain; proboscis without
stylets; cerebral organ present; a caudal cirrus sometimes present; body
wall contains three muscle layers of which the outer is longitudinal and
between which and the circular muscles are the lateral nerves; cutis well
developed : 2 families and over 170 species.

FAMILY LINEIDAE.

Body usually very long, but in some species relatively short and
thick; a pair of conspicuous lateral sensory grooves usually on the head;
3 muscle layers in proboscis; the outer one being longitudinal; cephalic
gland small and slender: 10 genera and about 150 species.

Key to the genera of Lineidae here described:
«! Caudal cirrus not present.

6j Lateral sensory grooves wanting 1. PARAPOLIA

62 Lateral sensory grooves present 2. LINEUS

a, Caudal cirrus present.

&t Lateral sensory grooves wanting 3. ZYGEUPOLIA

b2 Lateral sensory grooves present.

cx Lateral body edges not thin ; animals cannot swim 4. MICBUEA

c2 Lateral body edges very thin ; animals swim 5. CEBEBEATULUS

1. PARAPOLIA Coe. Body cylindrical anteriorly, flattened poste-
riorly ; head not set off from body ; without sensory grooves on the head ;
eyes not present; cerebral organs a pair of flat

elevations: 1 species.

P. aurantiaca Coe. Color orange; length 25
cm.; width 10 mm.; thickness 4 mm.: Vineyard
Sound, at low-water mark.

2. LINEUS Sowerby. Body extremely long and
filiform or tape-like and very contractile; head
somewhat wider and tapering to a point; usually
with eyes : about 50 species ; cosmopolitan ; animals
cannot swim, and usually twist themselves into an
irregular mass.

L. ruber (0. F. Miiller) (L. gesserensis 0. F.
Mill.; L. viridis Johnston) (Fig. 335). Body
cylindrical ; color very variable, being green, brown,
or reddish ; a single row of 4 to 8 eyes on each side
of head ; 20 cm. or more ; width 6 mm. : common under stones in shallow
water from Long Island to Greenland; Alaska; Europe; breeds in June
at Woods Hole.

JB

Linens ruber ( Verrill) .
A, whole worm ; B,
head, showing lateral
groove.

208

PLATHELMINTHES

L. socialis (Leidy). Body very slender and flattened, 25 cm. long
and 5 mm. wide, green or brown in color; ventral side lighter than dor-
sal ; a single row of 4 to 6 very small eyes on each side of the head and a
single pair of larger eyes some distance in front of the others: common
from New Jersey to Bay of Fundy, living gregariously under stones,
between tide lines; breeds in mid- winter in Long Island Sound.

L. bicolor Verrill. Body small, 45 mm. long, 1.5 mm. wide, cylin-
drical but somewhat flattened, dark green with a mid-dorsal yellowish
stripe ; with a single row of 8 to 14 eyes on each side : among algae and
hydroids in shallow water in Vineyard and Long Island Sounds; very
common in certain localities.

3. ZYGEUPOLIA C. B. Thompson. Body cylindrical anteriorly and
flattened posteriorly; head very long and pointed and without lateral

sensory grooves; caudal cirrus
present: 1 species.

Z. rubens (Coe) (Z. litoralis
C. B. Thorn.*). Body slender
and 8 cm. long ; head pure white ;
body whitish : coast of New Eng-
land; southern California; on
sand flats between tide lines.

4. MICRTJRA Ehrenberg.
Small, flat, and soft nemerteans
with a caudal cirrus, which can-
not swim ; with 3 frontal organs ; '
often with many eyes: about 17
species.

M. caeca Verrill. Body dark
brown or yellow ; 10 cm. long and 2 mm. wide ; no eyes : Long Island and
Vineyard Sounds, at low-water mark; sexually mature in July and
August at Woods Hole.

M. leidyi (Verr.) (Fig. 336). Body thick anteriorly; flattened pos-
teriorly; 15 cm. long and 4.5 mm. wide; red or purple dorsally, usually
with a lighter median line and lighter ventrally; proboscis flesh color:
common from New Jersey to Cape Ann in the sand near low-water mark;
breeds in mid-summer.

5. CEREBRATTTLUS Renier. Body long, flat, and broad, with a small
pointed head and thin edges well adapted for swimming; eyes usually
absent; mouth a long slit; with 3 frontal organs; proboscis very long;
a caudal cirrus at hinder end: over 60 species; in all seas.

Fig. 336

Fig. 337

Fig. 336— Micrura leidyi (Verrill).
Fig. 337 — Cerebratulus lacteus (Verrill).

* See "Zygeupolia litoralis," etc., by C. B. Thompson, Proc. Acad. Nat. Sci., Pbila.,
Vol. 53, p. 657, 1901.

NEMEETEA 209

C. lacteus* (Leidy) (Fig. 337). Body 2 m. or less long and 25 mm.
wide; extreme length up to 6.5 m. ; flesh color; proboscis white: very
common in the sand near low-water mark from Florida to Maine; breeds
from March to May in Long Island Sound and in July in Casco Bay.

ORDER 3. HOPLONEMERTEA. (METANEMERTINI.)

Body often very long and .slender, but in many forms short and
thick; mouth in front of the brain, usually coinciding with the opening
of the proboscis; intestinal csecum present; proboscis provided with
stylets (Fig. 333) ; lateral nerve cords internal to the muscle layers of
the body wall; frontal sense organ present: 9 families and more than
200 species, which live in the sea, in fresh water, and on land; a few
species parasitic; development usually direct.

Key to the families of Hoplonemertea here described:

at Proboscis does not reach the hinder third of the body.l. EMPLECTONEMATIDAE
a2 Proboscis reaches almost to the hinder end of body.
&! Four eyes usually present, forming a quadrangle.
CL Mostly hermaphroditic; long, thin worms, some terrestrial.

2. PROSOEHOCHMIDAE

c2 Unisexual worms, short and thick 4. PROSTOMATIDAE

62 Eyes numerous 3. AMPHIPOBIDAE

FAMILY 1. EMPLECTONEMATIDAE.

Body very long and thin; proboscis short
and thick and with a single main stylet of
variable form; usually with very small eyes: 5
genera and about 25 species.

1. EMPLECTONEMA Stimpson. Mouth and
proboscis openings coincide ; usually with many
eyes, never only four; accessory stylets pres-
ent: 16 species.

E. gracile (Johnston) (Fig. 338). Head
end wider than body and with 20 to 30 eyes on
each side; length about 20 cm.; breadth 1.5

mm .; color green; stylets slender and curved

_. ._ j Fig. 338— Emplecto-

at the end : very common on Pacific coast north w nema gracile (Coe).

of San Francisco, in shallow water; Europe.

2. CARCINONEMERTESJ Coe. Body long and slender, cylindrical,
usually not coiled; mouth and proboscis coincide, the latter being

* See "On the Anatomy of a Species of Nemertean (Cerebratulus lacteus Ver-
rill)," by W. R. Coe, Trans. Conn. Acad., Vol. 9, p. 479, 1895. "The Habits and
Early Development of Cerebratulus lacteus," by C. B. Wilson, Quart. Jour. Micros.
Sci., Vol. 43, 1900.

t See "Nemerteaii Parasites of Crabs," by W. R. Coe, Am. Nat, Vol. 36, p. 431»
1902.

210 PLATHELMINTHES

rudimentary and without accessory stylets; 2 minute eyes: 2 species;
parasitic on crabs.

C. carcinophila (Kolliker). Body 15 mm. long when immature, and
40 mm. long when mature; color red: on Portumanus (Platyonichus)
ocellatus of the New England coast and on Carcinus mcenas and other
crabs of the European coast, being on the gills when immature and on
the eggs when mature.

FAMILY 2. PROSORHOCHMIDAE.

Body long and thin, but rather broad; 4 eyes usually present, form-
ing a transverse quadrangle: 3 genera and 15 species; marine or
terrestrial.

GEONEMERTES Semper. Body slender and long, but of small size;
proboscis as long as the body with a central and 2 or 4 accessory stylets ;
hermaphroditic or unisexual, viviparous or oviparous: terrestrial, occur-
ring in subtropical islands, or imported into greenhouses; usually under
stones or in rotting wood; about 8 species.

G. agricola (Willemoes-Suhm). Body 35 mm. long and 2 mm. wide,
very variable in color, usually milk white, brownish, or greenish;
hermaphroditic and viviparous: common near and in mangrove swamps
in Bermuda.

FAMILY 3. AMPHIPORIDAE.

Body usually relatively short and thick; intestinal diverticula
branched and usually not alternating regularly with the gonads; pro-
boscis with a single central stylet with a conical base and several acces-
sory stylets; cerebral organs large; usually numerous eyes: 3 genera
and over 70 species; in all seas.

Key to the genera of Amphiporidae :

01 Proboscis sheath without diverticula.

&! Eyes extending posteriorly only to brain region 1. AMPHIPOEUS

Z>2 Eyes extending posteriorly behind brain region 2. ZYGONEMERTES

02 Proboscis sheath with a small number of ventral diverticula. .3. PBONEUROTES

1. AMPHIPORUS Ehrenberg. Usually short and thick and very con-
tractile worms which cannot swim or roll up spirally; with numerous
eyes: over 70 species, including almost a third of all American
nemerteans.

Key to the species of Amphiporidae here described:

Ox Body yellow A. OCHBACEUS

c2 Body white A. IMPARISPINOSUS

03 Body reel , , , . . . , A. ANGULATVS

NEMERTEA

211

Fig. 339 — Amphipo-

rus ochraceus

(Verrill).

A. ochraceus Verrill (Fig. 339). Body somewhat flattened, with a

somewhat broader head; yellowish in color; 7 cm. long and 3 mm. wide;

eyes converging backwards: common between tide lines and beyond,

under stones, etc., in Long Island and Vineyard

Sounds; breeds in May and June.

A. imparispinosus Griffin. Body small, 25 to 50

mm. long; slender, slightly flattened posteriorly;

white in color, sometimes with a reddish or yellowish

tinge; ocelli in two groups on each side, converging

anteriorly, less than forty in number: very common

between tide lines, among algae, etc., on entire

Pacific coast.

A. angulatus (0. F. Miiller). Body stout with

convex back; reddish or brownish in color; 15 cm.

long and 8 mm. wide; head wider and set off from

body, white in front with white spot on each side

and an H-shaped figure in the middle; eyes nu-
merous: common under stones between tide lines

and beyond, from Cape Cod to Greenland; Puget Sound and north-
wards.

2. ZYGONEMERTES Montgomery. Body long and slender; head
broader than neck, with two pairs of lateral oblique
furrows; ocelli very numerous, extending back along
the sides of the body: 3 species.

Z. virescens (Verrill) (Fig. 340). Body slender
and rather flat, usually light green in color, up to 4
cm. long and 1.5 mm. wide; eyes numerous, in two or
three parallel lateral rows along the side of the body :
common between tide lines and beyond in Long Island
and Vineyard Sounds; California.

3. PRONEUROTES Montgomery. Like AmpTiiporus,
but with 5 midventral diverticula in the proboscis
sheath: 1 species.

P. multioculatus Mont. Body yellowish-brown in
color with numerous eyes in two groups; 20 mm. long
and 3 mm. wide : New Jersey coast ; between tide lines.

Fig. 340

Zygonemertea

virescens

(Verrill).

A, whole worm ;

B, forward end.

FAMILY 4. TETBASTEMMIDAE.

Body flat and slender or short and stout; 4 eyes usually present;
intestinal diverticula and gonads alternate regularly; cerebral organs in
front of the brain: 3 genera and about 75 species; in all seas, also in
fresh water.

212 PLATHELMINTHES

Key to the genera of Tetrastemmidae:

Oi Marine animals.

&! Body rather flat, soft in appearance 1. TETRASTEMMA

62 Body cylindrical, rigid in appearance 3. OEBSTEDIA

a2 Fresh-water animals 2. STICHOSTEMMA

1. TETRASTEMMA Ehrenberg. Body small, with the 4 eyes forming
a rectangle; occasionally each eye is double or represented by a group;
cephalic gland large; mestly unisexual, occasionally hermaphroditic: over
60 species.

Key to the species of Tetrastemmidae here described:

at Body slender.

61 Body widest at forward end, tapering to hinder end.

d Body whitish T. CANDIDUM

c2 Body more or less spotted T. VEBMICULUM

62 Body widest in the middle and tapering both ways T. ELEGANS

c2 Body rather stout with dorsal stripes T. VITTATUM

T. candidum (0. F. Miiller) (Fig. 341). Body very contractile and
slender, white, light green, or yellowish in color, 2 cm. long and .5 mm.
wide; head wide; hinder end tapering: common between
tide lines and beyond, among algae, from Long Island
Sound to Bay of Fundy; Europe.

T. elegans (Girard). Body slender, tapering from the
middle both ways; back with a median yellow and 2 lat-
eral brown stripes, 2 cm. long, 1 mm. wide: among eel
grass and on stones in Long Island and Vineyard Sounds.
T. vermiculum (Quatrefages). Body slender, pale yel-
low or reddish in color and more or less spotted; forward
end broader than the hinder, 2 cm. long, 1 mm. wide:
common on muddy bottoms between tide lines in Long
Fig! 341 Island and Vineyard Sounds; Europe.

T€candlduma T. vittatum (Verrill). Body rather stout, green or

(Verrii). yellowish in color, sometimes with 1 or 2 dorsal stripes,
5 cm. long, 4 mm. wide: common on muddy bottoms at low-water mark
and beyond in Long Island and Vineyard Sounds.

2. STICHOSTEMMA* Montgomery. Similar to Tetrastemma but with
3 pairs of eyes; excretory organs extending the length of the body: 7
species, in fresh water.

S. rubrum (Leidy) (S. asensoriatum Mont.). Body slender, 18 mm.
long, yellow or reddish in color and very transparent, with 6, rarely 4 or
8, eyes; preoral sense pit wanting; cephalic gland weak; hemaphroditic :
Pennsylvania and Connecticut; eastern United States.

* "The Habits and Natural History of Stichostemma," by C. M. Child, Am. Nat.,
Vol. 35, 1901,

NEMERTEA

213

3. OERSTEDIA Quatrefages. Body cylindrical, of similar
both ends, and rigid; 4 eyes forming a quadrangle; not over
long: 4 species; marine.

0. dorsalis (Abildgaard) (Fig. 342). Body 10 mm.
long and very slender; color variable, mottled with green,
red, or brown : in shallow water on both the east and west
coast of North America and in Europe, very common on
piles and stones.

form at
15 mm.

ORDER 4. BDELLONEMERTEA.

Fig. 342

Oerstedia

dorsalis,

showing the

front end of

the body with

the protruded

proboscis

(Verrill).

Body short, flat, thick, and broad, with a large sucker
at the hinder end; intestine without diverticula and con-
voluted; proboscis without stylets, its opening coinciding
with the mouth and almost as long as the body; no eyes

or cerebral organ: 1 genus
and 3 species, living commensally in the
branchial chamber of marine and fresh-
water mollusks; cosmopolitan.

MALACOBDELLA Blainville. With the
characters of the family: 3 species.

M. grossa (0. F. Miiller) (Fig. 343).
Hinder end of body broader than forward
end; male 3 cm. long and 8 mm. broad,
gray in color; female 26 mm. long and 13

Fig. 343 — Malacoldella grossa. mm. broad, yellowish or brownish in color :
A, entire worm (Verrill). 1,

proboscis ; 2, mouth ; 3, intes- m Mya arenana, Venus, and other pe-
tine ; 4, sucker. B, section

through the forward end (Biir- lecypods, on both Sides OI the north
ger). 1, mouth; 2, proboscis;
3, proboscis sheath. Atlantic.

SUBPHYLUM 2. NEMATHELMINTHES.*

Roundworms. Unsegmented, round worms, usually so elongated
and slender that they are called thread or hair worms, which are ento-
parasites in animals or plants or lead a free life in the water or in moist
earth. The body is not ciliated and is without paired appendages and
usually without external bristles, hairs, or suckers. With a very few
exceptions all are unisexual.

The subphylum contains 3 classes.

* See "The Determination of Generic Types and a List of Round Worms Genera
and Their Original and Type Species," by C. W. Stiles and A. Hassall, Bull. 79, Bur.
of An. Ind., Dept. of Ag., 1905.

214

NEMATHELMINTHES

Key to the classes of Nemathelminthes :

i No spiny proboscis at forward end ; intestine present.

&! Mouth and intestine not degenerate in adult; lateral lines present.

1. NEMATODA

&j Mouth and intestine degenerate ; lateral lines absent 2. GOEDIACEA

a Spiny proboscis present ; no intestine 3. ACANTHOCEPHALA

CLASS 1. NEMATODA.*

Threadworms (Fig. 344). Round, slender worms, usually white
or flesh color in appearance, which vary from microscopic size to a
meter in length. The integument consists of a cuticula
,<£ which is usually smooth on the outer surface and a soft

subcuticula; no hypodermis is present, but the subcuticula
is supposed to represent it. There is a voluminous body
cavity into which the subcuticula projects along the
median dorsal and ventral and the two lateral lines,
forming thus 4 prominent longitudinal ridges. In the
lateral ridges run the paired excretory canals, which open
to the outside by a pore just behind the mouth, and the
lateral nerve cords; and in the dorsal and ventral ridges
are also nerve cords. Lying next the subcuticula is a
single layer of characteristic, longitudinal muscle fibers,
•v no circular fibers being present. The nervous system con-

J sists of a nerve ring containing ganglion cells which sur-

rounds the oesophagus and a number of longitudinal nerves
extending both forwards and backwards, those going back-
wards being joined by transverse commissures. The only
special sense organs are simple eyes, which some nema-
todes possess, and also sensory papillae.

The body cavity is without mesenteries, transverse
septa, or peritoneal lining and contains blood. Lying in
it are the alimentary canal and the reproductive organs.
The mouth is at the forward end of the body and may be
surrounded by sensory lips or papillae, and armed with
chitinous teeth. The oesophagus is a muscular sucking-
organ into which a pair of long glands may open; its
hinder end may be constricted, causing the formation of one or two
swollen divisions, called oasophageal bulbs. The intestine is a straight
tube which passes to the anus near the hinder end of the body. The

* See "Monographic der Nematoden," by A. Schneider, 1866. "Die Susswasser-
fauna Deutschlands," by L. A. Jagerskiold and O. von Linstow, Heft 15, 1909. "The
Nematodes Parasitic in the Alimentary Tract of Cattle, Sheep," etc., by B. H. Ran-
som, Bull. 127, Bur. An. Ind., 1911.

Fig. 344

Diagram of

female

nematode
(Siissw. P.

Deut.).

1, mouth

2, nerve ring

3, oesophagus

4, excretory

pore

5, intestine
6, ovary

7, genital pore
8, anus.

NEMATODA 215

animals are, with a few exceptions, unisexual, the females being larger
than the males, with a genital pore near the middle or towards the for-
ward end of the body. The genital organs are simply formed tubular
structures. In the male the testis is usually a single tube which
communicates with the rectum. Anal papillae are often present; long
spicules also usually project from the anus of the male by means of
which it attaches itself to the female; in the Strongillidae and other
families an expansion of the hinder end called the bursa also serves the
same purpose. The spermatozoa are short and tailless. In the female
two genital tubes are present which meet near the external opening. The
distal ends of these are ovaries and produce the eggs while the proximal
ends act as uteri. The eggs of the various species have a characteristic
appearance by means of which the animals may be identified (Fig. 345).
Many nematodes are viviparous, the
young animals developing in the uterus.
Habits and Distribution.— Nematodes
are mostly active animals which move by
a peculiar whipping motion of the body.
With the exception of certain minute

forms which lead a free life in fresh . Jiff- 345— Eggs of various nema-

todes (from Ward). A, Ancylos-

and salt water and in decaying organic *oma duodenaie ; B, Necator amer-

icanus ; C, Ascaris lumbricoides ;

matter, they are internal parasites of PI lAsoaris canis ; • E> T.richuris
J trichiura ; F, Oxyuris vermicularis.

animals and plants, being among the

commonest parasites of man and the domestic animals. Like most para-
sites, many pass through a metamorphosis in their youth and may live
in two different hosts.

History.— Some of the commonest nematodes which 'are the cause of
disease in man and his domestic animals have been known for a very long
time and were much studied by the early zoologists. In 1808 Rudolphi
created the orders Nematoda and Acanihocephala, and in 1851 Vogt
formed a class of these two orders and the Gordiacea, which he called the
Nematelmia. The most active investigators of nematodes at the present
time in this country are the United States Department of Agriculture and
the Marine Hospital Service.

The class contains about 15 families and several thousand species.

Key to the families of Nematoda here described:

<&! Mostly non-parasitic nematodes.

&! Marine and free-swimming nematodes 1. ENOPLIDAE

62 In fresh water or in the ground ; a few parasitic in animals and plants.

2. ANGUILLULIDAE
az Parasitic nematodes.

\ Parasitic in invertebrates ; mouth with 6 papillae 3. MERMITIDAE

62 Parasitic in vertebrates.

216 NEMATHELMINTHES

Ci Mouth not surrounded by 3 prominent lips.
dt Body very long and filiform ; 4 pairs of papillae around the anus of

male 4. FILABIIDAE

da Anterior part of body with a very long and characteristic row of cells.

5. TBICHINELLIDAE

da Male with a large bell-shaped bursa 6. STBONGILIDAE

<?2 Mouth surrounded by 3 prominent lips 7. ASCABIDAE

FAMILY 1. ENOPLIDAE.

Minute, free-living worms, found principally in the sea, but also in
fresh water or in the earth; mouth often surrounded by hairs and
bristles ; oesophagus without bulb ; eyes often present ; male with spicules :
numerous species.

1. ENOPLUS Dujardin. Body elongate, tapering behind; cuticula
smooth; mouth with 6 papillae, behind which is a circlet of 10 to 12
bristles: numerous species in both salt and fresh water.

E. brevis Bastian. Lives among algae and hydroids in shallow
water; often greenish in color; length 5 mm.

2. DORYLAIMTJS Dujardin. Large worms; cuticula smooth, not
ringed; extreme front end set off by a constriction; mouth with papillae
and a large bristle: numerous species, which live at the roots of plants
in moist earth and water.

D. maximus Butschli. Length 7 mm.: in garden earth.

FAMILY 2. ANGUILLULIDAE.*

Minute worms which lead a free life in water or earth or decaying
substances, or are parasitic in plants or (rarely) in animals; mouth with-
out papillae; oesophagus with 2 bulbs; male with 2 spicules and some-
times with a bursa: numerous genera and species.

Key to the genera of Anguillulidae here described:

Oj Free-living worms, in soil or decaying substances.

&! Mouth with 2 or 3 teeth 2. DIPLOGASTEB

Z>2 Mouth without teeth.

<?! In vinegar or paste 1. ANGUILLULA

C2 In the earth or decaying substances 3. RHABDITIS

O2 Parasitic worms.
6j Parasitic in plants ; a spine in the mouth.

Ci In the roots of vegetables 4. HETEBODEBA

c2 In wheat (5. TYLENCHUS

Z»a Parasitic in animals.

Ci In the bumble bee 5. SPH^BULABIA

ca In man 7. STBONGYLOIDES

* See "Helminthological Contributions," No. 2, by J. Leidy, Proc. Acad. Nat Sci.,
Phila., Vol. 5, p. 224. "Monograph of the Anguillulidae," by H. C. Bastian, Transact.
Linn. Soc., London, Vol. 25, 1866. "On the Family Anguillulidae," etc., by J. Leidy,
Proc. A. N. S., Phila., Vol. 22, p. 68, 1870.

NEMATODA

217

Fig. 346

Diplogaster rivalis

(Siissw. F. Deut.).

A, whole worm

B, head.

1. ANGUILLULA Ehrenberg. Cuticula smooth and ringed ; body elon-
gate, tapering behind; vulva behind the middle; spicules long; no
bursa: several species.

A. aceti (0. F. Miiller). Vinegar eel. Length 2
mm.: in vinegar, living on the fungus forming the
" mother, " also in stale paste; has also been found in
the human bladder.

2. DIPLOGASTER M. Schultze. Body elongate;
cuticula ringed and often ridged; body tapering be-
hind ; mouth with 2 or 3 teeth and often with papillae
around it; male with or without bursa: numerous
species; in fresh water, earth, and decaying sub-
stances.

D. rivalis Leydig (Fig. 346). Length 2 mm.;
hind end tapering to a long, fine point; mouth sur-
rounded by a membrane around which are 6 short bristles: viviparous;
common in ponds and streams.

3. RHABDITIS Dujardin. Minute worms living in decaying sub-

stances or the ground; head end often constricted:
mouth triangular, usually with 3 to 6 lips; body
slender, ending with a point; male with 2 short
spicules: many species.

R. terricola Duj. Body without distinct rings, 1.4
mm. long; mouth cavity long, with 2 ring-shaped thick-
enings at its base: common.

4. HETERODERA Schmidt. Minute worms infecting
the roots of various plants, with a spine in the mouth
for piercing plant tissues: 1 species.

H. schachti* Schmidt (H. radicola 0. F. Miiller)
(Fig. 347). Male 1.5 mm. long, .045 mm. thick; female
1 mm. long and viviparous, being .5 mm. thick when
full of young: in the roots of various vegetables and
other cultivated plants, causing swellings.

5. SPHJERTJLARIA Dufour. Minute worms, free-
living and parasitic; male with a bursa; mouth with a
tooth: 1 species.

S. bombi Duf. The young animals, about 1 mm.
long, live in the earth; after pairing, the fertilized
females migrate into the body of a hibernating queen bumblebee; here
the uterus, filled with growing larvae, evaginates out of the vulva and

Fig. 347
Heterodera

schachti
(Stone and

Smith ) .

1, pharynx ; 2,
intestine ; :i, ex-
cretory pore ; 4,
genital pore and
anus ; 5, testes.

* See "Nematode Worms in the Greenhouse," by G. E. Stone and R. E. Smith,
Bull. No. r.5, Hatch Exp. Sta. of Mass., Ag. Col., 1898.

218

NEMATHELMINTHES

grows until it is many times the size of the rest of the worm, reaching
a length of 15 mm.; the young larvae are born in the bee.

6. TYLENCHTJS Bastian. Cuticula ringed; body tapering to a point
behind; mouth with a spine for piercing plant tissues; vulva much back
of the middle: numerous species, which are parasitic in plants.

T. tritici Bast. Male 2 mm., female 4.5 mm. long and spirally
rolled together; color yellowish: in wheat, in a grain of which several
larvae may live; when the wheat is sown the larvae migrate into the
young plants and finally become mature in the buds;
the eggs are laid here and the young larvae migrate
into the ripening grain and remain there; they can lie
in dried wheat for years without dying.

7. STRONGYLOIDES Grassi. Minute worms with
heterogony, a non-parasitic, unisexual generation alter-
nating with an hermaphroditic parasitic generation, the
former having a very long cylindrical oesophagus, the
latter with a short oesophagus with a bulb; no teeth
and 2 spicules present: 1 species.

S. ster cor alls* (Bavay) (Fig. 348). Hermaphro-
ditic form (S. intestinalis Bavay) 2.2 mm. long and
.034 mm. wide, with an oesophagus a quarter as long as
the body ; vulva in the hinder part of the body : it lives
in the human intestine and causes Cochin China diar-
rhoea, having been first observed in that country; a few large eggs are
produced, from which hatch rhabditiform larvae, which are about .3 mm.
long; they pass out with the feces and develop into the unisexual form, of
which the male is .7 mm. and the female is about 1 mm. long, and which
lead a free life; from their eggs the parasitic generation develops; in
this country and Europe only the parasitic generation is known.

FAMILY 3. MERMITIDAE.

Hairworms. Body long and filiform; mouth with 6 papillae; adults
Without anus; hinder part of the intestine solid; male with 2 spicules
and 3 rows of papillae: the young animals live in the body cavity of
insects, especially caterpillars, grasshoppers, and beetles, and occasion-
ally spiders and snails or crayfish, from which they migrate into the ground
or the water; here they become mature and lay their eggs; 1 genus.

MERMISJ Dujardin. With the characters of the family: several
species.

* See "Occurrence of Strongyloides intestinalis in the United States," by M. L.
Price, The Jour, of the Am. Med. Asso., Vol. 41, 1903.

t See "Observations," etc., by J. Leidy, Proc. A. N. S., Phila., Vol. 5, p. 262.
"A Synopsis of Entozoa," etc., by same. Ibid., Vol. 8, 1856, p. 42.

Fig. 348
Strongyloides
stercoralis
(Braun).
A, hermaphro-
ditic form
B, larva.

NEMATODA

219

M. nigrescens Duj. (Fig. 349). Body 12 cm. long, .5 mm. thick,
attenuated anteriorly and blunt behind; color white, with the black
ovary showing through ; the young worms migrate on warm
summer days from the body of their hosts, often in large
numbers, into the moist earth, causing a belief that they
have rained down.

FAMILY 4. FTLARIIDAE.* Fig. 349

Mermis

_»i . _ n,.n ,-,r>, 11 nigrescens

Body very long and nliiorm; mouth otten surrounded (Siissw. P.

by papillae or by 2 lips ; no oesophageal bulb ; male with 1

P^ spicule or with 2 of unequal size and with a spiral twist

\ of the hinder end; usually viviparous: several genera.
FILARIA 0. F. Miiller. Vulva towards the forward
end; male with 2 spicules, and much smaller than the
female: numerous species, which live in man and other
vertebrates as final hosts, and probably in insects or crusta-
ceans as intermediate hosts ; Leidy mentions over 30 species
in this country.

F. immitisf Leidy (Fig. 350). Length of male 18 cm.;
thickness .9 mm., with a corkscrew hinder end; length of
female 30 cm. ; thickness 1.3 mm. : in the heart and veins of
the dog, the .28 mm. long larvae appearing in the blood,
especially in the night time ; the larvae are transferred from
one dog to another by mosquitoes; very common in China
and Japan, and occurring in America and Europe ; it some-
times infects man.

F. bancrofti Cobbold (Fig. 351). Male
4 cm. long, .1 mm. thick and colorless;
female 8 cm. long, .28 mm. thick and
brownish in color: in the heart and lymph
vessels of man in the tropics, also in the
southern United States, the .3 mm. long
larvae appearing in the blood, but in the
surface circulation only at night ; the larvae
are transferred from one person to an-
other by mosquitoes; one of the causes of
elephantiasis.

F. loa (Cob.). Male 30 mm. long, .4 mm. thick, with 8 large cir-
cumanal papillae; female 41 mm. long and .5 mm. thick; body with

* See "The Zoological Characters of the Roundworm Genus Filaria," etc., by
C. W. Stiles, Bull. 34, Hygienic Lab., etc., 1907.

t See "Notices of Nematoid Worms," by J. Leidy, Proc. A. N. S., Phila., 1886,
p. 308.

Fig. 350

Filaria

immitis

(from Braun).

A, male
B, female.

Fig. 351 — Filaria bancrofti

(from Braun), showing

several worms among

blood corpuscles.

220 NEMATHELMINTHES

numerous small protuberances, irregularly distributed: beneath the con-
junctiva of the eye, in the eyelid, or in the subcutaneous tissue of other
parts of the body in man; on the west coast of Africa and occasionally
in America and Europe.

F. medinensis (L.). Medina or Guinea worm. Length of female
2 m. or less; thickness 1.7 mm.; color white or yellowish; intestine
atrophied ; male not known : in the subcutaneous tissue of man, espe-
cially in the legs, also in domestic animals, producing a sore which
breaks to the outside, freeing the embryos; the young are found in
Cyclops and are probably conveyed with drinking water into the human
body; in Africa and other tropical countries, and supposed to be the
"burning fiery serpents" which troubled the children of Israel in the
desert.

FAMILY 5. TEICHINELLIDAE.

Elongated worms with the forward portion attenuated, often ex-
tremely so; mouth without papillae or teeth; oesophagus slender, without
bulb, and very long, in some cases being half as long as the body, and
situated beneath a very characteristic row of conspicuously large cells;
male with 1 spicule or none; female with but 1 ovary: 3 genera and
numerous species, all internal parasites.

Key to the genera of Trichinellidae :

«! Forward portion very slender ; whip worms 1. TRICHURIS

aa Forward portion not whip-like.

\ Male without spicule 2. TRICHINELLA

52 Male with spicule 3. TRICHOSOMA

1. TRICHTTRIS Roederer (TrichocepJialus Goeze).
Body made up of 2 portions, a very slender forward
portion, containing the oesophagus, and a thick hinder
portion, containing the reproductive organs; hinder
end of male rolled up and with spicule; vulva at the
forward end of the thick portion: in the large intes-
tine, especially the caecum, of mammals; development

direct, infection resulting from swallowing the eggs;
Fig. 352
Trichuris tricMura 1 species.

A, female; B, male, T. trichiura* (L.) (TrichocepJialus dispar Ru-

end imbedded in dolphi) (Fig. 352). Whip worm. Male 45 mm. long;

mucous mem- female 50 mm. long; eggs (Fig. 345, E) ellipsoid, .05

mm. long and .023 mm. thick: in man, cosmopolitan;

perhaps the commonest intestinal parasite in man and often the indirect

cause of appendicitis and typhoid fever.

* See "A Statistical Study of the Prevalence of Intestinal Worms in Man," by
C. W. Stiles and P. E. Garrison, Bull. No. 28 of Hygienic Lab., 1906.

NEMATODA

221

2. TRIOHINELLA Railliet (Trichina Owen). Minute worms, with the
forward portion not much slenderer than the hinder; male without spic-
ule but with 2 conical projections at hinder end; viviparous; anus
terminal: 1 species.

T. spiralis* (Owen) (Fig. 353). Male 1.5 mm. long; female 3.5 mm.
long; young born alive: in the small intestine of man, the pig, rat, and
ether animals. The young worms, which are about .1 mm. long, are the
cause of trichinosis. They bore their way
through the intestinal wall of the host and
migrate in the blood and lymph to the muscles,
where they encyst themselves and frequently
so lame the muscles of the jaws, neck, and
thorax that their functioning is interfered with
and death may ensue. If meat containing the
cysts be eaten by another animal or a person
the worm is released and passing into the in-
testine quickly becomes mature. Man gets the
infection by eating insufficiently cooked pork
containing the cysts; the pig gets it by eating
offal or rats. The rat is supposed to be the
original host of the worm,

3. TRICHOSOMA Rudolphi. Body hair-like,
the forward portion not much slenderer than
the hinder; usually a single spicule present:
in birds and mammals; numerous species.

T. tenuissimum Diesing. Male 10 mm.
long; female 17 mm. long: in duodenum of
the pigeons.

T. crassicaudum Bellingham. Female 17 mm. long; forward end
rounded and with small protuberances back as far as the vulva; male
2.5 mm. long, without spicule, and lies often in the female vulva: in the
liver and other organs of the rat.

Fig. 353 — TrichineUa spi-
ralis (from Ransom). A,
female ; B, male ; C, a piece
of pork containing cysts ;
D, an enlarged cyst. 1, fe-
male genital pore; 2, em-
bryos in the uterus; 3,
ovary ; 4, anus ; 5, testis.

FAMILY 6. STBONGYLIDAE.

Mouth surrounded by several papillae; no oesophageal bulb; hinder
end of male expanded to form a broad bursa (Fig. 355, B), also with
1 or 2 spicules: numerous genera and species which live in the intestine,
lungs and other organs of vertebrates, especially mammals.

* See "Trichinosis in Germany," by C. W. Stiles, Bull. No. 30, Bureau of An.
Ind., TJ. S, Dept. of Ag., 1901,

222 NEMATHELMINTHES

Key to the genera of Strongylidae here described :

«! Bursa well developed.

&! Bursa without ribs ; 1 spicule 1. DIOCTOPHYME

6a Bursa with ribs ; 2 spicules.
Cj Mouth small, without teeth.

di Male and female not permanently attached 2. DICTYOCAULUS

dz Male and female permanently joined together 3. SYNGAMUS

€3 Mouth large, with teeth.
dt Without oral glands.

ei Without ventral teeth but with cutting plates 4. NEGATOR

ez With ventral teeth 5. ANCHYLOSTOMA

d2 Two long oral glands 6. STRONGYLUS

02 Bursa small ; in fishes 7. CUCULLANUS

1. DIOCTOPHYME Collet (Eustrongulus Diesing). Large worms with
6 prominent oral papillae; bursa without ribs; 1 spicule present; vulva
near forward end: 1 species.

D. renale (Goeze) (D. gigas Rudolphi) (Fig. 354). Body generally
blood red; male 40 cm. long or less and 6 mm. thick; female 1 m. long or
less, and 12 mm. thick; egg (Fig. 345, A) ovoid, brown,
and about .068 mm. by .04 mm. : in the kidney of the dog
and other domestic animals as well as rarely in man.

2. DICTYOCAULUS Railliet and Henry. Mouth with 6
small papillae, bursa large with ribs and two spicules;
female genital pore behind the middle: many species.

D. filaria (Rudolphi). Body white and thread-like,
from 3 to 10 cm. in length ; egg about .12 mm. by .06 mm. :
in the bronchi of sheep and goats, causing often a dan-
gerous bronchitis.
Pig 354 ^' rufescens (Leuckart). Body brown and thread-

Dioctophiime like, from 18 to 35 mm. long; egg about .1 mm. by .06
(fronTward). mm.: in the bronchi and lungs of sheep and goats, causing
often pneumonia.

3. SYNGAMUS von Siebold. Male permanently attached by the
bursa to the vulva of the much larger female, which is forward of the
middle, forming together a Y-shaped object; bursa ribbed: 1 species.

S. trachealis v. Sieb. Body red; male 6 mm. long; female 20 mm.
long: in the trachea of fowls, causing gapes.

4. NEGATOR Stiles. Head end narrower than body and curved
dorsally; mouth large, opening obliquely into a chitinous buccal capsule,
the dorsal portion of which is shorter than the ventral; buccal cavity
has ventrally a pair of prominent semilunar cutting plates or lips and
dorsally a pair of smaller lips and a conical tooth projecting into it; a
large bursa with 2 long, barbed spicules : 2 species, in man and anthropoid
apes.

NEMATODA

223

N. americanus* (Stiles). American hookworm (Fig. 355). Male 9
mm. long; female 11 mm. long; vulva in forward half of body; eggs
(Fig. 345, B) about .07 mm. long by .038 mm. broad: in the small intes-
tine of man and the gorilla, where it moves about sucking blood, causing

Fig. 355 — Necator americanus. A, dorsal view of head, showing cutting lips and teeth

(Looss) ; B, hinder end of male, showing bursa (Stiles).

1, ventral cutting lips.

often a severe aenemia; very common in the South among the poorer
classes; the eggs pass out with the feces, the young worms living in the
moist earth; infection may be got by drinking infected water, by eating
infected substances, and even as the result of the migration of the young
worms through the skin of feet or hands.

5. ANCHYLOSTOMA Dubini. Similar to Neca-
tor but with head end not narrower than body
and with 2 pairs of large ventral-curved teeth
and a pair of dorsal teeth in place of the cutting
plates, directed forwards ; vulva in hinder half of
body: 5 species.

A. duodenale Dub. (Figs 345, A, and 356).
Old World hookworm. Length of male 9 mm.;
of female 12 mm.: in man, in Europe and Asia,
occasionally in America.

A. caninum (Ercolani). Similar to the above
but somewhat larger : common in dogs and cats and often fatal to young
animals.

6. STRONGYLTJS 0. F. Miiller. Similar to Anchylostoma but with
two long glands opening into the mouth, around which are small flat
spines: numerous species.

* See "Report upon the Prevalence and Geographic Distribution of the Hook-
worm Disease in the United States," by C. W. Stiles, Bull. No. 10, Hygienic Lab.,
Treas. Dept., 1903. "Uncinariasis in the South," by C. A. Smith, The Jour, of the
Am. Med. Asso., Vol. 41, p. 709, 1903. "The Anatomy and Life History," eta, by A.
Looss, Records of School of Med., Cairo, 1911,

Fig. 356

Anchylostoma duodenale
— dorsal view of head,
showing teeth (Looss).
1, ventral teeth.

224 NEMATHELMINTHES

S. equinus Mull. The armed palisade worm. Male 20 to 30 mm.
long ; female 23 to 55 mm. long, 2 mm. thick ; body red or brown, straight
and rigid; mouth with small teeth; egg .09 by .05 mm.: common in the
cascum or colon of the horse, causing colic; the young worms live in
water and moist earth and pass directly in drinking water into the
horse; they are also found in the abdominal arteries where they cause
aneurisms.

7. CUCULLANUS 0. F. Miiller. Small worms with 2 lateral chitinous
plates on the head and with rudimentary bursa; mouth ridged longi-
tudinally ; male with a spicule ; vulva in the middle of the body : several
species.

C. elegans Zeder. Male 8 mm. long; female 13 mm. long; body
yellowish or reddish; mouth with 6 papillae: in the intestine of the
perch and other fish.

FAMILY 7. ASCAEIDAE.

Body often rather stout and large; mouth surrounded by 3 promi-
nent lips, 1 dorsal and 2 ventral; oesophagus with 1 or 2 bulbs; hinder
end of male spirally curved and usually 1 or 2 spicules project from the
anus: several hundred species, almost all intestinal parasites in
vertebrates.

Key to the genera of Ascaridae here described:

«! Large nematodes with prominent lips 1. ASCABIS

o2 Small nematodes with usually small lips.

5X Male with a sucker before the anus 3. HETERAKIS

52 No sucker present 2. OXYTJRIS

1. ASCAEIS L. Large worms in which the 3 lips are set off by a
constriction, forming a distinct knob at the front end of the body;
oesophagus without distinct bulb; male with 2
equal spicules and numerous ventral caudal papil-
lae: several hundred species, which live in the
intestines of birds and mammals.

A. lumbricoides L. Eelworm (Fig. 357). Male

15 to 25 cm- lons> 3 mm- thick; female 20 to 40

Cm' lon^ 5 mm' thick 5 e^ (Fi^ 345> C) b™wn,
frnodn;t S;d?ntral VieW °f with roughened surface, about .06 mm. by .05

mm.; body with the appearance of an earth

worm: in the small intestine of man and domestic animals, sometimes in
considerable numbers, especially in children, when they are dangerous
parasites; occasionally found in the liver, trachea, and other organs;
development direct, the eggs pass out with the feces, and the young
larvae develop in water or moist earth ; infection is got in drinking water,
or from the ground or from the skin of raw fruits.

NEMATODA

225

Fig. 358
Ascaris cants.
Cross section
showing fins
(from Braun).

A. equonim Goeze (A. megalocephala Cloquet). Maw worm. Length
15 to 37 cm. ; thickness 8 to 12 mm. ; eggs spherical, .1 mm. in diameter :
in the small intestine of the horse, often in large num-
bers, when it is a dangerous parasite.

A. canis (Werner) (A. mystax Zeder) (Fig. 358).
Male 6 cm. long, 1 mm. thick; female 18 cm. long; a
pair of fin-like projections on the sides of the head;
eggs (Fig. 345, D) almost spherical, about .07 mm. in
diameter: in the intestine of cats and dogs, usually
common, occasionally in man; development direct.

2. OXYURIS Rudolphi. Small worms in which the 3 lips are more
or less indistinct; oesophagus long, with 'a bulb followed by a dilated
portion; hinder end of male very short with but 1 spic-
ule; vulva in forward half; hinder end of female taper-
ing to a sharp point: about 15 species; in the large
intestine of vertebrates, also in certain insects.

0. vermicularis (L.). Pin worm (Fig. 359). Female
10 mm. long; .6 mm. thick; male 4 mm. long; a dorsal
and a ventral cuticular projection on the head; egg
(Fig. 345, F) .05 mm. by .02 mm.: in the large intes-
tine, also occasionally in other parts of the digestive
tract of man, especially of children; often the indirect
cause of appendicitis; development direct, the eggs of
the females being taken in with drinking water or
directly from the hands.

3. HETERAKIS Dujardin. Lips as in Ascaris; male
with a large sucker surrounded by 4 papillae before
the anus and 2 lateral thickenings; oral papillae small:
numerous species.

H. vescularis Froehlich. Length 7 to 15 mm.; tail
of male with 5 preanal and 7 postanal papillae ; no teeth
in mouth : in the large intestine of chickens and ducks.
H. brevicauda (Zeder). Length 5 mm.; mouth surrounded by 10
papillae : in the intestine of frogs and toads.

Fig. 359

Oxyuris

vermicularis

(from Braun).

A, female

B, male.

1, oesophagus

2, vulva; 3, anus.

CLASS 2. GORDIACEA *

Hair worms. Long and very slender worms of the same diameter
throughout and never sharply pointed behind, which are sometimes found

* See "The Gordiacea of Certain American Collections," by T. H. Montgomery,
Bull. Mus. Comp. Zool., Harvard, Vol. 32, 1898. Ibid., by the same, Pt. 2, Proc.
Cal. Acad. C. Sci., 3rd Ser., Vol. 1, 1898. "Synopsis of the Gordiacea," by the same,
Am. Nat, Vol. 33, p. 647, 1899.

226 NEMATHELMINTHES

wriggling actively in fresh-water ponds and ditches, and look much like
thick horsehairs. Sometimes a number are found in a tangled mass, a
feature which suggested the name of the typical genus. As larvae the
worms live in the body cavity of insects, whence they migrate into the
water, their sudden appearance often giving rise to the common belief
that they are metamorphosed horsehairs.

The integument consists of a thick cuticula and a hypodermis, the
latter being a single-layered epithelium and very different from the sub-
cuticula of nematodes. Beneath the integument is a muscle layer consist-
ing of a single layer of longitudinal muscle cells. The body cavity is
lined with a peritoneum and traversed by dorsoventral mesenteries and
is nearly filled with a mass of connective tissue cells forming a sort of
parenchyma. The mouth and oesophagus in adults are closed and the
intestine is a straight tube proceeding to the anus at the hinder end of
the body. Special respiratory, circulatory, and excretory organs are
absent.

The nervous system consists of a nerve ring round the oasophagus
with two dorsal swellings and a median ventral cord. The sense organs
are a pair of eyes and numerous tactile bristles. The
sexes are separate; two testes and two ovaries are
present and in both sexes the reproductive organs open
to the outside through the anus.

The eggs are laid in long strings in the water, the
length of one observed by Leidy being 91 inches, and
containing 6 million eggs. The young larvae (Fig.
360), after hatching, seeks some aquatic insect larva
into which it bores its way by means of bristles on the head. It remains
here in the muscles or fat body until the insect is eaten by some other
water insect or fish or has completed its larval life 'and left the water as
an adult. If in the latter case the host is eaten by a predaceous beetle
the larval worm may pass into its second larval stage in its body cavity,
or in !a grasshopper or other insect if the first host dies and the young
larva falls upon the ground. In its second host the worm grows rapidly
and assumes the long hair-like form of the adult, and finally breaks its
way through the body wall of its host and falls into the water or is swept
there by the rain, where it becomes mature.

The class contains 2 families and about 15 American species. The
second of these families is very different from the first and its relationships
are rather obscure.

Key to the families of Gordiacea:

«i Fresh-water and terrestrial worms 1. GOBDIIDAE

Oj Marine worms 2. NECTONEMATIDAE

GORDIACEA

227

FAMILY 1. GOEDIIDAE.

With the characters of the order: 4 genera.
Key to the genera of Gordiidae here described:

G! Hinder end bilobed or trilobed.

Z>! Hinder end bilobed and rolled spirally.

<?! Head end not obliquely truncated 1. GOEDIUS (male)

c2 Head end obliquely truncated 2. PAKAGORDIUS (male)

62 Hinder end trilobed 2. PABAGOBDIUS (female)

o2 Hinder end not forked.

&! Hinder end rolled spirally 3. CHOBDODES (male)

Z>2 Hinder end not rolled spirally.

GI Hinder end not swollen 1. GOBDIUS (female)

ca Hinder end swollen and knob-like 3. CHOBDODES (female)

1. GOEDIUS L. Hair worms with a forked and spirally rolled tail
and often a V-shaped ridge behind the anus in the male, and a straight,
unforked tail in the female: about 10 species.

Cr. aquaticus L. (G. robustus Leidy) (Fig. 361). Length 28 to 89
cm.; thickness .5 to 1 mm.; color white or brown; ends blunt; V-shaped
postanal ridge in male: cosmopolitan.

Fig. 361

Fig. 362

Fig. 363

Fig. 361 — Gordius aquations; hinder end of male (Montgomery). Fig. 362 —
Gordius lineatus; hinder end of male (Montgomery). Fig. 363 — Paragordius varius.;
hinder end of female (A) and male (B) (Montgomery).

G. lineatus Leidy (Fig. 362). No distinct V-shaped ridge behind
the anus, on each side of which in the male is a longitudinal line of
hairs; color yellowish-white; female with longitudinal rows of cuticular
areoles: eastern states.

2. PARAGORDITJS* Camerano. Hair worms with a forked and spirally
rolled tail in the male, and a trilobed tail in the female: 1 species.

P. varius (Leidy) (Fig. 363). Length 10 to 30 cm.; head of male
obliquely truncated; the commonest gordian: occasionally occurs in
human digestive tract; North America.

3. CHORDODES Mobius. Hair worms with the hinder end spirally
rolled and not forked in the male, but not rolled and with a knob-like
posterior swelling in the female : 5 species.

* See "Observations on the Natural History of the Gordiacea," by J. Leidy,
Proc. A. N. S., Phila., Vol. 5, p. 262. "The Adult Organization of Paragordlus varius
Leidy," by T. H. Montgomery, Zool. Jahrb., Vol. 18, p. 387, 1903.

228

NEMATHELMINTHES

C. morgani Montgomery (Fig. 364).
brown; head white: eastern states.

Length 6 to 22 cm.; color

FAMILY 2. NECTONEMATIDAE.

Marine worms with body faintly ringed externally
and with 2 rows of fine bristles on each side ; anus absent ;
tail of male curved ventrally and ends with
a conical projection: 1 genus and species',
which is found swimming at the surface of
the sea.

NECTONEMA Verrill. With the char-
acters of the family.

N. agile* Verr. (Fig. 365). Length of
male 5 to 20 cm.; of female 3 to 6 cm.;
thickness .3 to 1 mm.; color grayish-white:
marine, and pelagic at Newport, R. I., and Woods Hole; Naples; the
larval form parasitic in small crustaceans (Palcemonetes) .

Fig. 364

Chordodes

morgani ;

hinder end of

female
(Montgomery)

\

3

Fig. 365
Nectonema

agile (Ward).

CLASS 3. ACANTHOCEPHALA.f

Elongated, parasitic worms which live as adults in the intestine of
vertebrates, to the walls of which they attach themselves by means of a
retractile proboscis armed with hook-like spines, and as larvae in the
bodies of small invertebrates, especially crustaceans.

The body of the adult may be divided into three regions, the proboscis,
the neck, and the trunk. The proboscis is a more or less cylindrical struc-
ture at the front end of the body provided with several rows of recurved
spines. The neck is a continuation of the proboscis, but is without spines
and is sharply set off from the trunk. The trunk forms the principal
part of the body and is usually smooth, but may be annulated or spinose.
The integument consists of a cuticula and a subcuticula; in the latter is a
network of fibers and also large spaces of lacunae, and beneath it are
circular and longitudinal muscle fibers. A large body cavity is present.
Extending backwards from the base of the proboscis in most forms is the
proboscis sheath, a muscular sac into which the proboscis can be invagi-
nated and thus retracted. In certain forms, however, the sheath is inserted
near the middle or forward end of the proboscis, in which case it can be
only partially retracted or not at all. Extending backwards from the base

* See "On Nectonema agile Verrill," by H. B. Ward, Bull. Mus. Comp. Zool., Vol.
23, p. 135, 1892.

t See "Geschichte und Ergebnisse der Echinorhynschen Forschung," etc., by M.
Lube, Zpol. Annalen, Vol. 1, p. 139. "Acanthocephalen," by M. Liibe, Siisswasser-
fauna Deutscblands, Heft 16, 1911. ,

ACANTHOCEPHALA

229

of the neck is a pair of long projections of the subcuticula called the
lemnisci, the function of which is not known. The excretory system con-
sists of a pair of nephridia which unite and open into the reproductive
duct. The nervous system consists of a central ganglion in the proboscis
sheath and two main nerves which run backwards ; no special sense organs
are present. No digestive tract is present.

The Acanthocephala are unisexual. Extending back from the probos-
cis sheath is a prominent band-like structure called the ligament which ends
in the hinder part of the body cavity. In the male two ovoid testes are
connected with the ligament, the vasa deferentia, with which several glands
are joined, passing back to the complex genital opening at the hinder end
of the body. In the female the ovary is also in the ligament; the ova
escape into the body cavity whence they pass through an oviduct of com-
plicated structure to the external opening at the hinder end of the body.
Fertilization takes place in the body cavity and the embryonic development
takes place there. The eggs then pass out and in order to develop farther
must be swallowed by a crustacean or insect. The larval worm then bores
through the intestinal wall of this intermediate host and encapsules itself
in the body cavity, where it remains until the intermediate host is swal-
lowed, probably usually in drinking water, by the final host, to the intes-
tinal wall of which it fastens itself. The class contains 4 families, 12
genera, and over 100 species.

FAMILY 1. ECHINORHYNCHIDAE.

With the characters of the
order: several genera.

1. ECHINORHYNCHTJS 0. F.

Mtiller. Body smooth, although
often wrinkled after death: nu-
merous species.

E. anguillae Mull. (Fig.
366). Body orange-colored, 6 to
29 mm. long; proboscis with 8 or
10 rows of hooks; neck long: in
numerous fresh-water fish; com-
mon; Europe; larva probably in
Gammarus and small fishes.

E. ranae Schrank. Body 5
to 60 mm. long; proboscis with 12

Fig. 366 — Echin orhynchus anguillae
(Siissw. F. Deut.). A, entire worm: 1,
proboscis ; 2, lemnisci; 3, proboscis
sheath ; 4, ligament ; 5, testis ; 6, genital
pore ; B, proboscis.

to 20 rows of hooks : in frogs, toads, and salamanders ; common ; Europe ;
larva in Asellus.

230 TROCHELMINTHES

FAMILY 2. GIGANTOKHYNCHIDAE.

Body large, and annulated; lemnisci long and twisted: 1 genus.
GIGANTORHYNCHUS Hamann. With the characters of the family:
1 species.

G. hirudinaceus (Pallas) (G. gigas Block) -(Fig.
367). Body white, tapering posteriorly, proboscis almost
spherical and with 6 rows of 8 hooks each; male 6 to 9
cm. long and 4 mm. thick; female up to 50 cm. long and

Fig. 367 4 to 9 mm. thick : in the intestine of pigs and often a

Gigantorhynchus . .

giga* (Ward). common and dangerous parasite; the intermediate host a

B, male. beetle grub, which pigs often eat.

SUBPHYLUM 3. TROCHELMINTHES.

Minute, aquatic animals which in structure bear a close relation to
the trochophore larva of the annelid worms and mollusks. The body is
unsegmented and often externally annulated or ringed and is never com-
pletely ciliated, although in most of them groups of cilia occur in certain
regions. A spacious body cavity is present, which is not however limited
by a peritoneum. The Rotifera, by far the largest of the three classes, are
characterized by the ciliated disc-like front end of the body and usually
also the forked organ of attachment at the hinder end. The other two
classes comprise a few species of peculiar microscopic worms which are
often included among the Rotifera, but which lack the anterior disc and
differ from them also in other important respects. The subphylum con-
tains 3 classes.

Key to the classes of TrochelmintJies:

Oi External cilia present.

\ Anterior ciliated disc present 1. ROTIFEBA

ft2 Ventral surface only ciliated 2. GASTROTRICHA

as External cilia absent 3. KINORHYNCHA

CLASS 1. ROTIPERA *

Rotifers or wheel animalcules (Fig. 379). Microscopic, aquatic ani-
mals, the body of which is composed of three divisions, the head, the trunk,
and the foot. The head bears the corona, which is a ciliated disc forming

* See "The Rotifera or Wheel Animalcules," by C. T. Hudson and P. H. Gosse,
1889. "The Rotifera of Sandusky Bay," by D. S. Kellicott, Proc. Am. Mic. Soc., Vol.
18, p. 155, 1896. "The Rotifera of Sandusky Bay," by same. Ibid., Vol. 19, p. 43,
1897. "Rotatoria of the United States," by H. S. Jennings, Bull. U. S. Fish. Com.
for 1899, p. 67, 1900. "Synopsis of the Rotatoria," by same, Am. Nat, Vol. 35, p.
725. "Die Siisswasserfauna Deutschlands," Heft 14, 1912. "Index of the Rota-
toria," by H. K. Harring, Bull. 81, U. S. Nat. Mus., 1913.

EOTIFERA 231

the front end of the body and in the middle of which is tne mouth, and
the special sense organs. The cilia are evenly distributed over the corona
in the most primitive rotifers; in others the corona is variously lobed and
the cilia are in groups and usually confined to the margin and the area
just within the margin. These marginal cilia in numerous common rotifers
whirl in opposite directions on the two sides of the corona and resemble
revolving wheels, giving the group its name. The special sense organs,
when present, consist of one to three eyes and one to four tentacles. The
trunk is in many rotifers encased in a shell called the lorica which is the
thickened cuticula; it is often provided with spines 'and other projections.
The foot forms the hinder portion of the body : it is usually retractile and
in most rotifers ends with one, two, or several toes. Glands are present
in it which secrete an adhesive substance by means of which the animal
can attach itself temporarily.

The mouth opens into a large muscular pharynx called the mastax
in which are paired jaws or trophi, the working of which is a noticeable
feature in rotifers. In some rotifers (Stephanops) the pharynx is thrust
out of the mouth and used as a proboscis to take in food. A narrow
oesophagus joins the pharynx with the large stomach, which has a pair of
large gastric glands and is joined with the dorsal anus by the short intes-
tine. In some forms the intestine ends blindly, there being no anus. The
nervous system consists of a brain dorsal to the pharynx and nerves ex-
tending from it; a suboesophageal ganglion is present in some forms. A
pair of kidney tubules which contain flame cells open into a contractile
bladder, the vacuole, which communicates with the hinder end of the intes-
tine. The sexes are distinct. The males are small and without digestive
organs and usually much less numerous than the females ; in many species
they have not been found at all. The female has usually a single small
ovary and a large yolk gland which are joined with the cloaca by 'an ovi-
duct, the lower end of which acts as a uterus and retains the young, in a
large number of species, during development, so that they are born alive.
The females reproduce parthenogenetically : at certain times, however,
males are born and the fertilized eggs then produced are called "winter7'
or resting eggs and can resist cold and drought. Budding and fission do
not occur.

Habits and Distribution.— The majority of rotifers are solitary, free-
living animals, although a few species are sessile, living in tubes com-
posed of their own secretions or of foreign matters, and a few are colonial.
They are typically fresh-water animals and are everywhere abundant, but
a few species are marine. They are also usually rather rigidly confined
to certain environments, some living among plants and some being pelagic.
Most of the common species are cosmopolitan in their distribution. Some

232 TROCHELMINTHES

rotifers and their eggs can withstand desiccation many years when taken
from the water and are often blown great distances by the wind or carried
on the feet of birds. The food of most forms consists of minute plants
and animals, but a few species are parasitic.

History.— Rotifers have been known since the time of Leeuwenhoek,
who discovered them in 1703. 0. F. Miiller in 1786 gave those known at
his time binominal names, classifying them with the Infusoria. Ehren-
berg, in his epoch-making work on Infusoria published in 1838, described
great numbers of rotifers and laid the foundation of the present classifi-
cation. Wiegmann in 1832 had, however, already removed them from the
Infusoria and placed them among the worms. The monograph of Hudson
and Gosse contains the modern classification of the group.

About 850 species of Eotifera are known, of which about 250 occur
in this country. They are grouped in 3 orders.

Key to the orders of Eotifera:
a: Sessile or colonial and usually tubicolous (except Trochosphcera) .

1. RHIZOTA
O2 Free-swimming; not tubicolous and non-colonial rotifers.

Z>! Rotifers which creep like a leech, but can also swim 2. BDELLOIDA

62 Rotifers which do not creep but swim 3. PLOIMA

ORDER 1. RHIZOTA.

Usually sessile rotifers living in tubes composed of a transparent
secretion or of fecal or other substances; some forms are colonial and a
few are free-swimming: 3 families.

Key to the families of Khizota here described:

<*! Corona with prominent non-vibratile cilia usually on lobes ; vibratile cilia

very small 1. FLOSCULARIIDAE

o, Corona without non-vibratile cilia; colonial or not 2. MELICEBTIDAE

FAMILY 1. FLOSCULAKIIDAE.*

Solitary, sessile, or free-swimming rotifers living in a transparent
tube; corona lobed in most cases and bearing groups of long, often non-
vibratile cilia; vibratile cilia few, about the mouth: 3 genera.

Key to the genera of Flosculariidae here described:
<*! Lobes of corona knobbed or blunt, or absent 1. FLOSCULARIA

02 Lobes long and pointed 2. STEPHANOCEBOS

1. FLOSCTJLARIAJ Oken. Body in a transparent tube; corona with

3 to 5 lobes, or not lobed, and bearing long non-vibratile cilia ; the young
of all and the adults of certain species free-swimming: about 30 species.

* See "On the Morphology of the Rotatorian Family Flosculariidae," by T. H.
Montgomery, Jr., Proc. Acad. Nat. Sci., Phila., 1903, p. 363.

t See "On Floscularia Conklini Nov. Spec., with a Key for the Identification of
the Known Species of the Genus," by T. H. Montgomery, Jr., Biol. Bull., Vol. 5,
p. 233, 1903.

EOTIFERA

233

Fig. 369
Stephanoceros

fimbriatus
(Montgomery).

F. ornata Ehrenberg. Lobes 5, each with a round knob which bears
the cilia; foot about twice as long as the body; no eyes; length .5
mm.: common and sessile; among water plants.

F. campanulata Dobie (Fig. 368).
Lobes 5, distinct and not knobbed; cilia
non-vibratile on entire margin of the
bell-shaped corona; sessile; length .6
mm. : often common.

F. pelagica Rousselet. Corona cir-
cular, but slightly lobed with short,
non-vibratile cilia; free-swimming.

2. STEPHANOCEROS Ehrenberg.
Lobes 5, very long, slender, and point-
Fig. 368 ed» the cilia on them being non-vibra-
campani?Za?a tile and in rows or whorls; tube trans-
(Montgomery). parent; foot very long. I species.

S. fimbriatus (Goldfuss) (8. eiMornii Ehr.) (Fig. 369). Length
1.5 mm.: on aquatic plants; not common.

FAMILY 2. MELICEKTIDAE.

Colonial or not; usually tubicolous; corona 2 or 4-lobed with a
continuous row of large marginal cilia; 1 to 3 antennae, 1 dorsal and 2
ventral: 10 genera.

Key to the genera of Melicertidae here described:

Oj Non-colonial rotifers.

5j Corona distinctly 2 or 4-lobed.

cx Corona 4-lobed 1. MELICERTA

ca Corona 2-lobed 2. LIMNIAS

6a Corona oval or nearly circular and indistinctly 2-lobed.

o, Colonial rotifers. 3' CEciSTES

&! Colonies sessile, tubicolous or not.

<?! Not tubicolous 4. MEGALOTROCHA

c2 Animals in transparent tubes 5. LACINULARIA

62 Colonies free-swimming, animals tubicolous . 6. CONOCHILUS

1. MELICERTA Schrank. Corona large, with 4 large
lobes; 3 antennae, 1 minute dorsal and 2 larger ventral
ones: 4 species.

M. ringens Schrank (Fig. 370). Tube formed of
spherical pellets ; length .8 mm. : common on water plants.

M. melicerta (Ehrenberg). Tube gelatinous; length 1mm.; ventral
antennae very long: on water plants.

2. LIMNIAS Schrank. Corona broad, with 2 lobes; tube membra-
nous, often roughened by dirt and sometimes annulated; antennae as in
Melicerta: 3 species.

ringens

(from Siissw.

F. Deut.).

234

TROCHELMINTHES

Fig. 371

Limnias

ceratophulU

(from Siissw.

F. Deut).

L. ceratophyUi Schrank (Fig. 371). Tube not annulated; length
1 mm.; ventral antennae short: on water plants; abundant.

L. annulatus Bailey. Tube annulated; body with 5
horn-like dorsal processes; length 1 mm.

3. (EciSTES Ehrenberg. Corona a wide oval; lobes
indistinct ; tube irregular or absent ; dorsal antenna minute
or absent: 10 species.

0. crystallinus Ehr. Tube variable, transparent, often
covered with dirt; ventral antennae small, wide apart;
length .5 mm.

0. melicerta (Ehr.). Two long dorsal projections just
below the corona, sometimes antler-like; tube formed of
pellets and very short, or wanting: common.

4. MEGALOTROCHA Ehrenberg. Colonial and sessile,
each colony appearing to the eye as a grayish ball; not
tubicolous; corona broad, reniform; antennae inconspicu-
ous: 2 species.

M. alboflavicans* Ehr. (Fig. 372). Four opaque warts
in a row just beneath the corona; length 2 mm., of colony
5 mm.

5. LACINTTLARIA Schweigger. Colonial and similar to
Megalotrocha but each individual is in a transparent tube:

1 species.

L. socialis (Pallas). Length 2 mm., of colony 3
mm. : on water plants ; less common than above.

6. CONOCHILUS Ehrenberg. Free-swimming pelagic
colonies, each individual in a transparent tube: 3
species.

C. volvox Ehr. Colony spherical, consisting of 10
to 40 individuals arranged radially; ventral antennae
separate except at base; length .6 mm., of colony 1
mm.: common.

C. unicornis Rousselet (Fig. 373). Colony irreg-
ular, containing few individuals; a single large ventral antenna situated
on the corona : common.

ORDER 2. BDELLOIDA.

Non-tubicolous rotifers (with a few exceptions) which swim with
the corona and creep like a leech by attaching alternately the front and
hind ends of the body; body cylindrical, with a cuticula composed of
rings which can be telescoped; foot usually ending with 3 toes and with

* See "The Formation of New Colonies of the Rotifer Megalotrocha alboflavicans
Ehr.," by F. M. Surface, Biol. Bull., Vol. 11, p. 182.

Megalotrocha

alboflavicans

(from Siissw.

F. Deut.).

Fig. 373

Conpchilus

unicornis

(from Siissw. F.

Deut.).

ROTIFERA

235

2 or 4 spurs a little way up; a dorsal proboscis behind the corona >
ovaries 2: 2 families.

FAMILY PHILODINIDAE.

Corona composed of 2 circular and separated retractile lobes, making
2 distinct wheels; proboscis and tentacle present: 4 genera.

Key to the genera of Philodinidae here described :

Oi Two eyes present.

&! Eyes on the proboscis 1. ROTIFER

62 Eyes on neck, directly over the brain and the jaws 2. PHILODINA

a2 Eyes absent 3. CALLIDINA

1. ROTIFER Schrank. Body long and slender and
very retractile: among plants and dirt: 9 species.

R. vulgaris Schrank (Fig. 374). Body whitish and
opaque, gradually tapering to the foot, which makes
up half the animal ; spurs not twice as long as width of
body; length .5 mm.: common; also in salt water.

R. tardigradus Ehrenberg. Body dark brown in
color, long and slender; spurs 3 times as long as the
width of body where attached ; length .8 mm. : common.

2. PHILODINA Ehrenberg. Body rather thick, fusi-

form; 2- red eyes behind the pro-
boscis; often in infusions: 6 species.

P. aculeata Ehr. Dorsal surface of body beset with
strong spines ; length .5 mm. : common.

P. roseola Ehr. (Fig. 375). Body rather slender
and often rose-colored; foot not distinctly set off;
length .5 mm.: common.

3. CALLIDINA Ehrenberg. Body elongate, without
eyes, the jaws often with fine transverse ridges: many
species.

C. elegans Ehr. Each jaw with 10 ridges, cuticula
smooth; length .35 mm.: common in infusion.

Fig. 374

Rotifer vulgaris

(Sussw. P. Deut.).

A, the animal.

B, head end.

1, proboscis

2, eyes
3, tentacle.

Fig. 375
Philodina roseola

(from
Stissw. F. Deut.).

ORDER 3. PLOIMA.

Non-tubicolous rotifers, which swim and do not creep like a leech,
but may creep with the toes or may leap ; some are parasitic : 2 suborders.
Key to the suborders of Ploima:

G! Without shell (lorica) 1. ILLOEICATA

o2 With lorica 2. LOBICATA

SUBORDER 1. ILLORICATA.

Ploimate rotifers with a flexible cuticula and no shell (lorica) : 6
families.

236 TROCHELMINTHES

Key to the families of Illoricata here described:

GX No foot present ; animals transparent, short and more or less spherical.
&! Animals spherical with a ring of cilia near equator .... 1. TEOCHOSPH^EIDAE
ft. Body sac-shaped.

<?! No long lateral appendages 2. ASPLANCHNIDAE

ca Long lateral appendages present with which the animal jumps.

3. TBIABTHBIDAE

02 Foot with 2 toes present.

Z>! Corona with 3 to 7 large prominences with setae 4. HYDATINIDAE

6a Corona without these ; body elongate, often with a pair of ciliated pro-
jections ( auricles) 5. NOTOMMATIDAE

FAMILY 1. TROCHOSPH^ERIDAE.

Spherical rotifers without corona or foot and with an encircling
band of cilia near the equator or towards the forward pole; mouth
ventral and anus at the hinder pole; the viscera are in the hinder hemi-
sphere: 1 genus.

TROCHOSPHJERA Semper. With the characters of the family : about

3 species.

T. solstitialis Thrope (Fig. 376). Band of cilia between equator
and forward pole ; diameter 2 mm. : in the Illinois River and at Put-in-Bay,
Lake Erie; Asia.

FAMILY 2. ASPLANCHNIDAE.

Large transparent sac-shaped rotifers, without anus and usually
pelagic: 3 genera.

1. ASPLANCHNA Gosse. Foot absent; jaws large; animals vivipa-

Fig. 377 Fig. 378

Fig. 376 — Trochosphcera solstitialis (Delage et He>ouard). 1, brain; 2, mouth;
3, kidney tubule ; 4, anus ; 5, intestine ; 6, ovary ; 7, dorsal nerve. Fig. 377 —
Asplanchna herricki (from Stissw. F. Deut.). Fig. 378 — Polyarthra platyptera (from
Siissw. F. Deut.).

rous, the embryo being frequently seen in the mother; 1 or 3 eyes present;
corona with two slight elevations: about 7 species.

A. priodonta Gosse. Body without humps and barrel-shaped; eyes
3; length .5 mm.: often very common; pelagic.

A. herricki* De Guerne (Fig. 377). Body amphora-shaped and
without humps; eyes 3: pelagic.

* See "Early Development of Asplanchna herrickii," by H. S. Jennings, Bull.
Mus. Comp. Zool., Vol. 30, 1896.

EOTIFERA

237

2. ASPLANCHNOPUS De Guerne. Foot present; animals viviparous:
2 species.

A. multiceps Schrank. Foot small; length 1 mm.: pelagic.

FAMILY 3. TEIARTHBIDAE.

Foot absent; long paired appendages at the side by means of which
the animal skips or swims and which may give it the appearance of a
crustacean: several genera.

POLYARTHRA Ehrenberg. Body rectangular with 12 long blade-
shaped appendages with serrate edges arranged in
4 groups: 1 species.

P. platyptera Ehr. (Fig. 378). One eye pres-
ent ; length .15 mm. : very common both at surface
and bottom.

FAMILY 4. HYDATINIDAE.

Body cylindrical or sac-shaped with a short
foot which has 2 small toes; corona with a number
of elevations bearing setae: 5 genera.

1. HYDATINA Ehrenberg. With-
out eyes, but with a tentacle: 8
species.

H. senta* Ehr. (Fig. 379).
Body large, .5 mm. long, trans-
parent: often common.

2. NOTOPS Hudson. Single eye
present; corona large with a ring
of cilia and bearing several large
prominences crowned with setae:
several species.

N. brachionus (Ehrenberg)
(Fig. 380). Body large, quadran-
gular and transparent; foot half as long as body
length .5 mm.: often common.

FAMILY 5. NOTOMMATIDAE.

Fig. 380

Notops

brachionus

(from Siissw.

F.Deut.).

Fig. 379

Hydatina senta

(Sttssw. F. Deut.).

1, corona ; 2, mouth ;

3, mastax ; 4, gastric

gland ; 5, stomach ; 6,

ovary ; 7, yolk gland ;

8, lateral sense organ ;

9, intestine; 10, kid-
ney tubule ; 11, vacu-
ole: 12, anus; 13,
adhesion glands ; 14,
toes.

and little retractile;

Body soft and elongate; corona oblique in position, without lobes,
and covered with cilia and often with a pair of lateral ciliated projec-
tions called auricles: 15 genera.

* See "Studies in the Life Cycle of Hydatina senta," by A. F. Shull, Jour. Ex.
Zool., Vols. 8, 10, and 12, 1910-1912. "The Influence of Food in Controlling Sex in
Hydatina senta," by D. D. Whitney, same, Vol. 17, 1914.

238

TEOCHELMINTHES

Key to the genera of Notommatidae here described:
Oj Auricles present.
Z>! Body not conspicuously annulated.

G! Very large rotifers with 3 or 5-lobed brain 1. COPEUS

c2 Not large and brain not lobed 2. NOTOMMATA

62 Body conspicuously annulated 3. TAPHEOCAMPA

o2 Auricles absent.

&! Toes minute 4. PBOALES

63 Toes conspicuous 5. FUBCULARIA

1. COPEUS Gosse. Large rotifers, slow-moving, usually enlarged
behind the middle; brain 3-lobed; body projects backward from the foot,
forming a tail; auricles present: 7 species; vegetable feeders.

C. pachyurus Gosse (Fig. 381). Tail rounded and thick; auricles
large; brain 3-lobed; foot 2-jointed; length .33 mm.

Fig. 381

Fig. 382

Fig. 383

Fig. 381 — Copeus pachyurus (from Siissw. F. Deut.). Fig. 382 — Notommata tripus
(Siissw. F. Deut.). Fig. 383 — Taphrocampa annulosa (Siissw. F. Deut.).

2. NOTOMMATA Ehrenberg. Small rotifers with an elongate body
and auricles; tail usually present; foot and toes usually small: many
species; among water plants.

N. tripus Ehr. (Fig. 382). Tail as long as the toes, the animal
appearing to end behind in 3 toes; length .1 mm.

N. truncata Jennings. Body red in color, long and truncate at each
end ; cilia extending on to ventral surface ; foot very small.

3. TAPHEOCAMPA Gosse. Body small and with numerous perma-

nent annulations; small tail just above the foot: 4 species.

T. annulosa Gosse (Fig. 383). Minute rotifer with a cyl-
indrical body and with a pair of small auricles ; length .1 mm.

4. PROALES Gosse. No auricles or tail present; toes
inconspicuous; body small and cylindrical: 8 species.

P. sordida Gosse. Body thick; head broad, with an eye;
foot very broad; toes conical; length .22 mm.

5. FURCTTLAEIA Ehrenberg. Auricles absent; body cyl-
indrical or bulging in the middle; toes conspicuous; eye red
at apex of head : 12 species.

F. forficula Ehr. (Fig. 384). Body cylindrical, with straight sides
and .35 mm. long: abundant.

Fig. 384
Furcularia

forficula

(Siissw. F.

Deut.).

EOTIFEEA 239

SUBORDER 2. LORI CAT A.

Lorica present, usually much flattened: 12 families.
Key to the families of Loricata here described:

«! Foot absent 1. ANUILEIDAE

o2 Foot present.

61 Foot transversely wrinkled or ringed (not jointed).

G! Foot ending in a ciliated cup, without toes 2. PTERODINIDAE

c2 Foot ending in 2 toes 3. BRACHIONIDAE

62 Foot not wrinkled or ringed, often jointed, with 1 or 2 toes.
Cj Toes not long and spine-like.

di Foot jointed ; lorica without dorsal spines 3. BRACHIONIDAE

d2 Head with a chitinous covering like the visor of a cap ; foot and toes

often very long ; 1 eye 4. DINOCHARIDAE

C2 Foot usually very short and ending in 1 or 2 slender and usually long

toes ; lorica usually flattened and ovate.
di No arched shield over head.

Cj Toes very slender and bristle-like, often very long 5. RATTULIDAE

ea Toes 1 or 2 in number, slender and rod-shaped 6. CATHYPNIDAE

e3 Toes 2 in number, long and diverging 7. ETJCHLANIDAE

d2 An arched shield over head 8. COLUBIDAE

FAMILY 1. ANUE^EIDAE.

Foot absent; lorica usually with 6 long spine-like projections at its
anterior margin and 1 or 2 at its posterior : 3 genera.

ANTTR2EA Ehrenberg. Lorica thick walled and opaque,
marked with polygonal areas on its dorsal surface; empty
loricas frequently found: 7 species.

A. cochlearis Gosse. Lorica prolonged posteriorly into
a long spine, which, however, may be wanting; length
.16 mm.

A. aculeata Ehr. (Fig. 385). Lorica quadrangular
with a spine at each of the postero-lateral angles ; .15 mm.
long. Deut'>-

FAMILY 2. PTEBODINIDAE.

Foot cylindrical and transversely wrinkled or annulated; body very
retractile: 2 genera.

PTERODINA Ehrenberg. Lorica flattened; a pair of lateral semi-
circles of cilia on the corona; 2 eyes; foot ending in a ciliated cup: 3
species.

P. patina Ehr. (Fig. 386). Lorica very transparent, flat and cir-
cular and .17 mm. long, without teeth : common among algae.

FAMILY 3. BEACHIONIDAE.

Foot long, cylindrical, and usually not jointed, but annulated or
wrinkled, with 2 toes; lorica squarish and flattened and usually with
spine-like projections from its anterior margin: 3 genera.

240

TEOCHELMINTHES

1. BRACHIONUS Pallas. Lorica arched dorsally, flattened ventrally;
1 red eye: numerous species, some marine.

B. rubens Ehrenberg (Fig. 387). Six straight spines on anterior
margin; no posterior spines; color pinkish: often common.

B. bakeri 0. F. Miiller. Six spines on anterior margin, the 2
middle ones curving outward; 2 lateral spines on posterior margin may
be long, short, or absent ; length .25 mm. : often very common.

Fig. 386

Fig. 387

Fig. 388

Fig. 386 — Pterodina patina (Siissw. F. Deut.). Fig. 387 — Brachionus rubens (Siissw.
F. Deut.). Fig. 388— No tens quadricornis (Stissw. F. Deut.).

B. militaris Ehr. Foot jointed; lorica with 10 anterior and 4 pos-
terior spines, its surface facetted and covered with raised points;
length .25 mm.

2. NOTETJS Ehrenberg. Foot jointed; lorica oval and with 2 ante-
rior and 2 posterior spines; no eye: 1 species.

N. quadricornis Ehr. (Fig. 388). Dorsal surface facetted, whole
surface roughened; length .35 mm.

FAMILY 4. DINOCHAEIDAE.

Lorica more or less cylindrical and usually with an
anterior dorsal projection over the head; foot very long
with 2 long toes: 4 genera.

1. SCARIDIUM Ehrenberg. Lorica vase-shaped, smooth,
and transparent, without the dorsal projection; 1 eye;
foot and toes very long: several species.

S. longicaudum (0. F. Miiller) (Fig. 389). Body
cylindrical; toes and foot longer than the rest of the
body; .4 mm. long.

2. Stephanops Ehrenberg. Head covered with a large
semicircular shield; foot and toes not usually long; 1 to 3
long movable spines project from the back : several species.

S. longispinatus Tatem. One long spine from the middle of back;
length .15 mm.

Fig. 389

Scaridium

longicaudum

(Siissw. F.

Deut).

EOTIFEEA
FAMILY 5. RATTULIDAE.*

241

The very short foot ends in one or more slender, often very long,
bristle-like toes; lorica more or less cylindrical; 1 eye: 2 genera and
35 species.

1. RATTULUS Lamarck. One long toe, often as long as
the rest of the body; a short toe also usually present which
is not a third the length of the long toe: 20 species.

R. longiseta (Schrank) (E. bicornis Ehrenberg) (Fig.
390). Two spines of unequal length at the anterior margin
of the lorica ; toe two-thirds the length of the body ; length
.5 mm.: common.

R. mucosus Stokes. Lorica with 2 parallel ridges close
together for half its length ; body ovoid : length .2 mm. : often
common.

2. DIUBELLA Bory de St. Vincent. Two toes present of equal

length or one more than a third the length of the other:
14 species.

D. tigris (0. F. Miiller) (Fig. 391). Toes equal and
long; body cylindrical, .2 mm. long with a tooth on
anterior margin of the lorica: very common in aquatic
vegetation in quiet water.

D. porcellus (Gosse). Toes slightly unequal, folded

Fig. 391 under the body, which is short, curved, and .15 mm. lone;

Diurella tigris , . .

(Jennings). lorica with 2 marginal teeth: very common.

Fig. 390
Rattulus
longiseta
(Siissw. F.

Deut.).

FAMILY 6. CATHYPNIDAE.

Body broad ; dorsal plate convex, ventral plate flat, the 2 plates sep-
arated by a deep groove on each side; foot very short with 1 or 2 rod-
shaped toes; 1 eye: 3 genera.

1. CATHYPNA Gosse. Lorica oval or nearly
circular; 2 toes: 3 species.

C. ungulata Gosse. Body large, being .3 mm.
long, including toes ; dorsal plate projecting over the
foot ; toes half as long as lorica : often very common.

C. lima (0. F. Miiller) (Fig. 392). Toes two-
fifths as long as lorica; each with a distinct shoulder at side near the
tip; length .2 mm.: often common.

2. MONOSTYLA Ehrenberg. Body oval or nearly circular, with 1
rod-like toe: 10 species.

Fig. 392

Cathypna luna

(Siissw. F. Deut.).

* See "The Rotatoria of the United States, II ; a Monograph of the Rattulidae,"
by H. S. Jennings, Bull. U. S. Fish. Com., Vol. 22, p. 273, 1903.

242

TEOCHELM1NTHES

M. bulla Gosse (Fig. 393). Dorsal plate very high; ventral plate
somewhat convex; anterior margin with a notch; .25 mm. long: very
common among aquatic plants.

FAMILY 7. EUCHLANIDAE.

Large transparent rotifers with a convex dorsal and
a flat or slightly convex ventral plate; foot jointed, with
2 large, diverging, blade-shaped toes: 2 genera.

ETICHLANIS Ehrenberg. Lorica oval and flat; eye
present: 7 species.

E. dilatata Ehr. (Fig. 394). Lorica with a pair
of lateral flanges projecting from its ventral plate;
anterior dorsal margin with a broad gap having a
straight bottom; length .3 mm.: often very common in
aquatic vegetation.

FAMILY 8. COLUEIDAE.

Monostyla bulla
(Jennings).

Head surmounted by an arched shield, appearing in a side view like
a hook: 5 genera.

1. METOPIDIA Ehrenberg. Lorica flattened, usually turtle-like in
appearance; usually 2 eyes: 11 species.

M, lepadella Ehr. (Fig. 395). Lorica oval, without teeth or spines

Fig. 394

Fig. 395

Fig. 396

Fig. 394 — Euchlanis dilatata (Sussw. F. Deut.). Fig. 395 — Metopidia lepadella
(Sussw. F. Deut.). Fig. 396 — Monura colurus (Hudson and Gosse).

or prominent angles; 2 eyes; ventral plate indented behind; length .08
mm. : often abundant among aquatic plants.

M. acuminata Ehr. Lorica oval, ending behind in a sharp point;
length .08 mm.: often common among aquatic plants.

2. MONURA Ehrenberg. Lorica arched, more or less compressed lat-
erally, often open mid-ventrally.

M. colurus Ehr. (Fig. 396). Length .1 mm.: often common among
in the sea,

GASTEOTEICHA 243

CLASS 2. GASTROTRICHA.*

Minute worms less than .5 mm. long with an elongated body, usually
forked behind, with a ciliated ventral surface and a dorsal surface either
bare or covered with bristles or scales arranged in longitudinal rows;
head end contains the mouth and usually bears a pair of eyes and
paired sensory bristles; digestive tract a straight tube with a long mus-
cular oesophagus, extending to the anus, which is in the dorsal surface at
the hinder end of the body ; a pair of long kidney tubules opens into the
intestine; a very large brain is present, dorsal to the oesophagus, from
which nerves radiate; animals hermaphroditic, paired ovaries and testes
being present in the hinder part of the body cavity ; no genital ducts are
present and it is not known how the very large eggs reach the outside;
development direct: fresh-water animals found among infusorians and
rotifers; about 32 species, of which 12 have been found in this country.

FAMILY CH.ETONOTIDAE.
With the characters given above: several genera.
Key to the genera of Chcetonotidae here described:
Oj Posterior end forked.
&! Back covered with spines or scales.

Cj Caudal forks short 1. CH^ETONOTUS

c2 Caudal forks very long and segmented 2. LEPIDODEBMA

&2 Back not covered with spines or scales 3. ICHTHYDIUM

o2 Posterior end not forked 4. DASYDYTES

1. CHJETONOTUS Ehrenberg.f Gastrotricha with a short, unsegmented
forked tail and with dorsal spines or scales;
head formed of 3 lobes, usually with 2 pairs

of tufts of sensory bristles and hi some species

.,, _ ., Fig. 397 — Chcetonotus

with a pair of eyes; ventral side lams (Stokes). A, dorsal
,, , 00 . aspect ; B, head,

flat: 23 species.

C. lams (0. F. Miiller) (Fig. 397). Back covered with
short conical spines, the posterior ones being usually the
larger; length .12 mm.: common.

C. longispinosus Stokes (Fig. 398). Back with 2

Fig. 398 transverse rows of lone: spines : often common.

Chwtonotus *•"

longispinosus 2. IiEPiDODERMA Zeller. Back covered with scales;

(Stokes).

tail forks long and segmented: several species.

L. rhomboides (Stokes) (Fig. 399). Forks of tail one-fourth the
length of the body and composed of 20 segments; a deep, transverse
depression back of the mouth ; length .3 mm.

* See "Beitrage zur Systematic der Gastrotrichen," by T. Griinspan, Zool. Jahrb.
Syst, Vol. 26, 1908. "Die Siisswasserfauna Deutschlands," Heft 14, 1912.
t See "Aquatic Microscopy," etc., by A. C. Stokes, p. 185, 1896.

244

TEOCHELMINTHES

3. ICHTHYDITTM Ehrenberg. Like Chatonotus except that the back
is bare: several species.

I. podura (0. F. Miiller) (Fig. 400). A pair of vertical spines on
the neck, and another pair near the hinder end ; length .07 mm. : common.

Fig. 399

Fig. 400

Fig. 401

Fig. 399 — Lepidoderma rhomboides (Sussw. F. Deut.). A, head; B, tail; C, dorsal

scales. Fig. 400 — Ichthydium podura (Sussw. F. Deut).

Fig. 401 — Dasydytes saltitans (Stokes).

4. DASYDYTES Gosse. Body wide, with a distinct neck and head and
no forked tail: several species.

D. saltitans Stokes (Fig. 401). Head with long cilia on both sides;
neck very flexible; 2 sets of long bristles cross each other on the back;
length .08 mm.: not common.

Fig. 402
Echinoderes

dujardini
(from Claus),

CLASS 3. KINORHYNCHA *

Minute marine worms less than .5 mm. in length;
body arched dorsally and concave ventrally, and composed
of a series of rings; body cavity not segmented; outer sur-
face not ciliated but provided with spines and bristles ; head
and neck retractile, with a ring of hooks around the
mouth and a number of long locomotory spines; hinder
end usually forked; paired genital pores and paired
excretory pores near hinder end; sexes separate: about 30
species.

FAMILY ECHINODEEIDAE.

With the characters given above: 2 genera.

ECHINODERES Dujardin. Eyes present: several species in the
Mediterranean and Atlantic.

E. dujardini Claparede (Fig. 402). Body composed of 13 rings; 2
red eyes; color reddish: in mud and on algae.

* See "Zur Kenntniss der Echinoderen," by C. Zelinka, Zool. Anz., Vol. 32, p. 130,

1908.

BRTOZOA 245

SUBPHYLUM 4. BRYOZOA.* (POLYZOA.)

Minute and mostly colonial animals which are attached to rocks,
plants, and other objects in the sea or fresh water. The colony is usu-
ally made up of hundreds or thousands of individuals which have arisen
from one another by a process of budding, and is often mosslike in
appearance, whence the name of the group. The Loxosomidae are the only
non-colonial family. The individual members of a colony are called the
zooids : they are more or less cylindrical in form and are af ten polymorphic
in structure. The outer wall of the zooid is in most cases a thick cuticula
secreted by a hypodermal cell layer : it is often hardened by the presence
of calcium carbonate and forms a rigid case within which lie the soft parts
of the animal. This case, which is called the ectocyst or zooecium (Fig.
406,8), will often remain long after the death of the animal and the dis-
appearance of the soft part. In Pectinatella and some other forms the
body wall is fleshy or jelly-like.

The soft parts of a zooid consist of the viscera and the tentacle-
sheath with the tentacles which constitute the anterior end of the body.
The tentacles are hollow and ciliated and are borne upon a prominent oval
or horseshoe-shaped ridge called the lophophore (Fig. 406,1).

The body wall below the tentacles is highly flexible and in the
Ectoprocta these can be completely retracted within the zocecium. In the
center of the lophophore is the mouth and in the Entoprocta the anus
also: in the Ectoprocta the anus is situated just outside of it. The ten-
tacles are the only portion of the external surface of the Bryozoa that
is ciliated.

The internal organs differ very much in the two great groups of the
Bryozoa and will be described when these are presented.

Distribution and Habits.— The majority of Bryozoa are marine, being
found from tide water to very great depths. Between tide lines and in
shallow water incrusting and creeping colonies which are attached to rocks,
shells, or seaweed are common, while in deeper water erect and branching
colonies are the more abundant. No Bryozoa are parasitic, although many
species live commensally with other animals or with plants. The group is a
very ancient one, occurring in the Cambrian and all subsequent formations.

* See "Report upon the Invertebrate Animals of Vineyard Sound," etc., by A. B.
Verrill, Rep. U. S. Com. Fish., 1871-72, p. 292. "British Marine Polyzoa," by
Thomas Hincks, London, 1880. "Synopsis of North American Invertebrates, I.
Freshwater Bryozoa," by C. B. Davenport, Am. Nat, Vol. 33, p. 593, 1899. "Sponges
and Bryozoa of Sandusky Bay," by F. A. Landacre, The Ohio Naturalist, Vol. 1, p.
96, 1901. "The Bryozoa. Papers from the Harriman Alaska Expedition," by Alice
Robertson, Proc. Wash*. Acad., Vol. 2, p. 315, 1900. "The Freshwater Bryozoa of
the United States," by C. B. Davenport, Proc. U. S. Nat. Mus., Vol. 27, p. 211, 1904.
"The Bryozoa of the Woods Hole Region," by R. C. Osburn, Bull. Bur. Fish., Vol. 30,
1912. "The Bryozoa of Tortugas," by same, Pub. No. 182, Cam. Inst., Wash., 1914.

246 BEYOZOA

History. — The Bryozoa were thought to be seaweeds by the earlier
naturalists. Linnaeus grouped them with the corals and hydroids. Here
they remained until 1830, when J. V. Thompson separated them from the
polyps because they possess a digestive tube and called them Polyzoa, by
which name they are still known by English and many American zoolo-
gists. In 1831 Ehrenberg performed the same service and called the new
group Bryozoa, which is the name in use among continental and many
American zoologists. In 1841 Milne-Edwards created the phylum Mollus-
coidea to include the Bryozoa and Tunicata, in which the first named group
will still be found in many textbooks. The terms Ectoprocta and Ento-
procta were introduced by H. Nitzsche in 1870.

About 1,700 species of marine and 35 species of fresh-water Bryozoa
are known, which are grouped in 2 classes.

Key to the classes of Bryozoa :

Oi Tentacles not retractile into the zorecium 1. ENTOPBOCTA

c2 Tentacles retractile 2. ECTOPBOCTA

CLASS 1. ENTOPROCTA.*

Minute, primitive Bryozoa, in which the anus is within the circle of the
lophophore. The body consists of a calyx or head and a contractile
stalk, the former containing the viscera. The lophophore is circular
and supports a single row of tentacles. The depression within the
lophophore, which is called the vestibule, contains the mouth and the
anus (Fig. 405) ; projecting over the former is a lip called the epistome.
The lophophore cannot be retracted into the zooecium, but the tentacles
can be rolled into the vestibule and partly covered by an integumental
fold which arises at their base.

The viscera fill almost the entire space within the body. What
space is left and the entire inner portion of the stem are occupied by a
gelatinous parenchyma, so that a definite body cavity is wanting. The
digestive tube is U-shaped, an O3sophagus, stomach, and intestine being
distinguishable. The genital organs consist of a pair of gonads which
open into the vestibule. The animals are either unisexual or hermaphro-
ditic: in Loxosoma davenporti the gonads function as ovaries first and as
testes later. A pair of kidney tubules with flame cells open either into
the vestibule or the rectum. The nervous system consists of a central
ganglion situated between the mouth and the anus and radiating nerves.

The Entoprocta are found in both salt iand fresh water. They are a
small group comprising about 20 species, which are grouped in 3 families.

* See "Studies in Pacific Coast Entoprocta," by A. Robertson, Proc. Cal. Acad.
Sci., Vol. 2, p. 320, 1900.

BRTOZOA

247

Key to the families of Entoprocta :

! Solitary Entoprocta 1. LOXOSOMIDAE

3 Colonial Entoprocta.

&! Fresh-water Entoprocta 2. URNATELLIDAE

&3 Marine Entoprocta 3. PEDICELLINIDAE

FAMILY 1. LOXOSOMIDAE.

Solitary Entoprocta, which, however, often
bear young buds, with 10 to 26 tentacles, with
a contractile stalk at the base of which is a
foot gland which is of use in attaching the
animal and may be wanting in the adult
animal, and with an obliquely placed lopho-
phore: 3 genera.

LOXOSOMA Keferstein. With the char-
acters of the family: 15 species, which are
usually associated with marine annelids.

L. davenporti* Nickerson ( Fig. 403 ) . Length
up to 2.4 mm.; small foot gland present; tenta-
cles numbering from 22 to 26 ; from
2 to 12 buds usually present; anus
elevated on a cone; mammary
organ present in the floor of the

vestibule to which developing embryos attach themselves to

get nourishment: abundant in Vineyard Sound.
L. minuta Osburn. Body oval, .3 mm.

long: on Phascolosoma and Phascolion on

New England coast.

FAMILY 2. TJRNATELLIDAE.

Colonial, fresh-water Entoprocta, each
colony consisting of a few zooids, which
rise from a common disc; stalks long and
jointed and branching: 1 genus.

URNATELLA Leidy. With the char-
acters of the family: 1 species.

U. gracilisf Leidy (Fig. 404). Stalk up to 4 mm. long; calyx about
a tenth as long and bell-shaped; usually 2 zooids in a colony: on the
under side of stones in running water, in the eastern and central states.

* See "Loxosoma davenporti," by W. S. Nickerson, Jour. Morph., Vol. 17,
p. 351, 1901.

t See "On Urnatella gracilis," by C. B. Davenport, Bull. Mus. Comp. Zool., VoL
24, 1893.

Fig. 403
Loxosoma davenporti

(Nickerson).

1, lophopbore ; 2. rectum
3, bud.

Fig. 404

Urnatella gracilis:

three individuals

(Davenport).

248

BRYOZOA

Colonial

Fig. 405
Pedicellina

cernua

(altered from

Osburn).

1, mouth

2, anus

3, stomach.

FAMILY 3. PEDICELLINIDAE.

marine Entoprocta in which the zooids rise from a creeping,
branching stolon; the stalk is long and separated from
the calyx by a diaphragm: 2 genera.

PEDICELLINA Sars. With the characters of the fam-
ily : 6 species, 3 in Long Island Sound.

P. cernua (Pallas) (P. nutans Dalyell; P. americana
Leidy) (Fig. 405). Calyx cup-shaped with 12 to 24
tentacles; stalk yellowish-red in color, with or without
spines on stalk and calyx and tapering towards the top:
on shells and algae in shallow water; Atlantic coast, from
Labrador to Florida; Europe; often common.

CLASS 2. ECTOPROCTA.

~Bryozoa living in large colonies, in which the anus is outside the
lophophore and this structure with the tentacles can be retracted into
the zooecium (Fig. 406). The body cav-
ity is an extensive space which is lined
throughout by a peritoneum consisting
either of a single layer of cells or thin
layers of an irregular cellular parenchy-
ma. In certain species the body cavities
of the zooids communicate with one an-
other. The digestive tract is a wide
ciliated U-shaped tube, the aboral por-
tion of which is the sac-shaped stomach.
Joining the aboral end of the latter or-
gan with the base of the body cavity is
a mesenterial strand called the funiculus.
The animals are hermaphroditic, the
gonads developing in the peritoneum, the
testes usually on the funiculus and the
ovaries on the lateral walls. The ova and
sperm, except in the fresh-water species,
fall into the body cavity, where fertili-
zation takes place. The eggs develop
in the body cavity up to the larval stage in certain species, when
the young animals reach the outside either through a birth opening
or as the result of the disintegration of the parent. In other forms the
fertilized eggs pass into special outgrowths of the body wall called ocecia
or ovicells (Fig. 414,1) and develop there. In the Phylactolcemata the

Fig. 406 — Diagram of an ectoproct

(Chilostomid).

A, a retracted animal ; B, an
extended animal (Delage et H6-
rouard). 1, lophophore ; 2, mouth ;
3, anus ; 4, operculum ; 5, retrac-
tile muscle ; 6, funiculus ; 7, di-
gestive tract ; 8, zooecium.

BRYOZOA 249

embryo develops in the ovary, receiving nutriment directly from the
body cavity.

All ectoprocts develop also asexually by budding, and thus produce
the branching and incrusting colonies which characterize the group. In
many species polymorphic zooids appear which differ much from the
others in structure and perform certain specialized functions. These are
the ooecia, which are brood chambers, above mentioned, the avicularia
(Fig. 411, A), birdhead-like structures which seize small animals in
their jaws, and are probably defensive in function but also function in
keeping the surface of the colony clean, and the vibracula (Fig. 411, B),
whip-like appendages which wave about in the water and are also defen-
sive. In the fresh-water Phylactolcemata disc-like buds called statoblasts,
which have a hard chitinous shell, develop on the funiculus and either
float or drop to the bottom on the death of the animal in the fall of the
year or in periods of drought. In the spring or on the return of the wet
season each statoblast gives rise to a young colony.

The Ectoprocta have great powers of regeneration. Periodically in
the marine species the soft parts of the animal, with the exception of the
body wall, break down and form a single round mass called the brown
body. Later new organs develop, the brown body apparently being
expelled from the body as waste matter.

Kidneys have not been certainly demonstrated in Ectoprocta. No
blood vessels are present, but a blood fluid fills the body cavity. The
nervous system consists of a ganglion between the mouth and anus and
nerves radiating from it: in many species no nervous system has yet
been seen. No special sense organs are found. The class contains 2
orders and the great majority of all Bryozoa.

Key to the orders of Ectoprocta:

Cj Mostly marine Ectoprocta, with a circular lophophore. . . .1. GYMNOL^MATA
aa Fresh-water Ectoprocta with a horseshoe-shaped or oval lophophore.

2. PHYLACTOI^EMATA

ORDER 1. GYMNOL^EMATA.

Lophophore circular; mouth can usually be closed by a flap called
the operculum; vibracula, avicularia, and ooecia often present: marine
Bryozoa (excepting the Paludicellidae) including about 1,700 species,
which are grouped in 3 suborders.

Key to the suborders of Gymnolcemata :
Ci Opening of zooecium wide and circular and not capable of being closed

by an operculum 1. CYCLOSTOMATA

o2 Opening of zooscium, when lophophore is retracted, more or less flattened
and capable of being closed by an operculum.

6x Operculum a movable horn-like valve 2. CHILOSTOMATA

&2 Operculum composed of a fringe of setae 3. CTENOSTOMATA

250

BRTOZOA

Fig. 407 — Crisia eburnea (Osburn).

SUBORDER 1. CYCLOSTOMATA.

Zooecia tubular, in most cases densely calcareous, with a wide ter-
minal, circular opening, and without operculum, avicularia, or vibracula :
4 families.

Key to the families of Cyclostomata here described:

«! Colony distinctly jointed, and erect 1. CEISIIDAE

a2 Colony not distinctly jointed, and either recumbent or erect.

&! Colony usually branching and recumbent, or more or less erect (discoid

in Diastopora) 2. TUBULIPORIDAE

63 Colony discoid 3. LICHENOPOBIDAE

FAMILY 1. CEISIIDAE.

Colony erect and branching, calcareous and with horn-like joints so
that it is more or less flexible, with jointed and often branching root
fibers given off from the base or from the internodes which serve to

fasten it; zooecia in 1 or 2 rows; ten-
tacles 8 in number; large ocecia pres-
ent: 1 genus.

CRISIA Lamouroux. With the
characters of the family: about 35
species.

C. eburnea (L.) (Fig. 407). Colony white in color, forming bushy
tufts from 8 to 25 mm. high; zooecia in 2 rows and alternate, slightly
curved out, almost entirely adnate: cosmopolitan; common from Long
Island Sound to Arctic Ocean; California;
Europe; from low- water mark to 80 fathoms.

FAMILY 2. TUBULIPOEIDAE.

Colony entirely creeping and incrusted or
more or less erect, either simple or branched and
often radiating from a central point; zocecia in
1 or several rows, adhering to one another lat-
erally, with the upper end more or less free:
about 5 genera.

TUBULIPORA Lamarck. Colony entirely re-
cumbent or partially erect, forming a variously
shaped expansion, either simple or branched;
zooids tubular, arranged in divergent series:
about 29 species.

T. flabellaris (Fabricius) (Fig. 408). Colony 12 mm. in diameter, of
a pale purplish color, flabellate when young, but more or less circular and
lobed when old; zooscia punctate, long, and slender, .15 mm. in diame-

Fig. 408

Tubulipora flabellaris
(Osburn).

BETOZOA 251

ter, crowded together and radiating from the center to the edge, and
with the outer ends erect: Long Island Sound to Greenland, on algae,
etc., in shallow water; Europe.

T. fimbria Lamarck. Colony 12 mm. in size ; fan-shaped and lobed ;
zooecia slender, not raised at the outer ends, and wrinkled transversely:
in shallow and deep water; North Atlantic; Europe.

T. liliacea (Pallas) (T. pruinosa Stimpson). Colony about 9 mm.
high and white, or often purple and punctate; branches in same plane:
Atlantic coast; Europe; on shells, hydroids, etc.

FAMILY 3. LICHENOPORIDAE.

Colony discoid, flat, or more or less raised, forming either a simple
disc or several confluent ones; zooecia partially erect, forming distinct
rows which radiate from a large central free area and are not close
together, the spaces between being porous : 2 genera.

LICHENOPORA Defrance (Discoporella Gray). Colony thin and lami-
nate, sometimes composite: about 30 species.

L. hispida Fleming. Single disc up to 6 mm. in diameter; each indi-
vidual with 10 short tentacles: North Atlantic, on shells, algae, etc., from
moderate to great depths; often common; Europe.

L. verrucaria (Fabricius). Disc 3 mm. in diameter; zocecium with
a rib : North Atlantic, south to Long Island Sound ; common ; Europe.

SUBORDER 2. CHILOSTOMATA.*

Colonies either erect or recumbent; zooids tubular, oval, or rectan-
gular, and calcareous, horn-like, or membranous, the opening usually not
terminal and usually closed by a movable operculum (Fig. 406) ; avicu-
laria, vibracula, and ooecia usually present: about 36 families, all being
marine, including the majority of Bryozoa.

Key to the families of Chilostomata here described :

Oj, Colony not incrusting or foliaceous but usually dendritic.
&! Colony composed of a creeping base and erect shoots ; no avicularia or
vibracula.

G! Zooids rising separately from the base 1. ^ETEIDAE

c2 Erect shoots composed of many zooids each 2. EUCBATEIDAE

&2 Colony dendritic, without a creeping base.
cx Avicularia sessile and fixed,
dj Colony slender.

e, Branches flattened 3. CELLULAKIIDAE

e2 Branches cylindrical 5. CELLABIIDAE

dt Colony foliaceous 6. FLUSTBIDAE

c2 Avicularia pedunculate and jointed 4. BICELLAEIIDAE

* See "Non-incrusting Chilostomatous Bryozoa of the West Coast," by Alice
Robertson, Univ. of Cal. Pub., Vol. 2, p. 235, 1905. "The Incrusting," etc., by same,
ditto, Vol. 4, p. 253, 1908. "The Chilostomatous Bryozoa," by G. M. R. Levinson, 1909.

252

BRYOZOA

Oj Colony incrusting or foliaceous and strongly calcified.
&! Colony incrusting ; front wall more or less membranous.

cx No ridges on front wall 7. MEMBBANIPOBIDAE

ca Front wall with prominent transverse or radiating ridges.

8. CEIBRILINIDAE
6j Front wall not membranous ; colony either incrusting or erect.

cx With a pore beneath the orifice 9. MICBOPOBELLIDAE

ca With no such pore.
d^ Zooecia not perpendicular to general plane of colony and usually

incrusting.
«i Opening of zooecium with an indentation in lower lip . . 10. MYEIOZOIDAE

e2 No such indentation 11. ESCHABIDAE

da Zooecia vertical and heaped irregularly together 12. CELLEPOBIDAE

FAMILY 1. ^TEIDAE.

Zooecia tubular and erect, rising separately from a creeping stolonic
stem with a terminal opening and a lateral membranous area at the
upper end; operculum subterminal; no avicularia
or vibracula: 1 genus.

JETEA Lamouroux. With the characters of
the family: 9 species.

A. anguina (L.) (Fig. 409). Zocecia about 1
mm. high, white and glossy, more or less bent,
with a spatulate upper end and a ringed stalk;
stolon with regularly occurring thickenings, each
of which is part of a zocecium: Long Island
Sound northwards from shallow to deep water on
hydroids and seaweed; often common; Pacific
coast; cosmopolitan.

FAMILY 2. EUCEATEIDAE.

Fig. 409
JEtea anguina (Osborn).

Colony erect and branching; the zocecia narrowest at the base and
expanding upwards, being linked together in a single row, or in double
rows placed back to back; openings usually oblique;
no avicularia, vibracula, or opercula: 5 genera.

1. ETTCRATEA Lamouroux. Colony composed of a
creeping stolon and erect branching shoots; zocecia in
a single row placed end to end ; opening large and oval ;
ocecia terminal ; tentacular sheath terminating above in
a ring of setae: about 4 species.

L. chelata (L.) (Fig. 410). Colony often much
branched, occasionally not erect; branches spring from just below the
opening: Vineyard Sound northwards, on seaweed, stones, etc., in shal-
low water and between tide lines; often common; Pacific coast;
cosmopolitan.

Fig. 410

Eucratea chelata
(Osburn).

BRYOZOA

253

2. GEMELLARIA Savigny. Colony erect, branching; zooecia joined
back to back, the pairs rising from the top of one another; aperture
large: several species.

G-. loricata (L.). Colony bushy, up to 20 cm. high, brown in color,
composed of long, straight branches; zooecia narrowed below; aperture
oval: in northern seas; Vineyard Sound northwards; Alaska; Europe.

6

FAMILY 3. CELLULAE1IDAE.

Colonies erect, dichotomously branched ; zooecia in 2 or more rows in

the same plane; avicularia and vibracula (Fig. 411), or the former alone,

almost always present; opening not terminal,

usually armed with spines and usually with

an operculum: 8 genera.

1. MENIPEA Lamouroux. Colony jointed,

zoo3cia oblong, widest above, attenuated down-
ward, usually with sessile avicularia and

ooacia; no vibracula: about 20 species, 7

American, mostly on the Pacific coast.

M. ternata (Ellis and Solander). Colony

in small tufts, 25 mm. high; zocecia in 2 rows,

alternate and arranged in groups of 3; long

fibers extend from the zooecia: circumpolar;

Cape Cod northwards from shallow to deep water, on
hydroids and shells ; Europe ; Pacific coast.

2. CABEREA Lamouroux. Colony not jointed;
zooecia in 2 or more rows, quadrangular or ovate, with
a very large opening; sessile avicularia and enormous
vibracula as well as long, clasping fibers present : about
15 species, 1 American.
C. ellisi (Fleming) (Fig. 412). Colony with numerous branches, 25

mm. high; zooecia in 2 to 4 rows and quadrangular; vibracula very long

and serrate: circumpolar; Vineyard Sound northwards, from shallow to

deep water; often common; Europe; Alaska.

Fig. 411
A, an avicularium

B, a vibraculum
(Delage et He"rouard).
1, nerve ; 2, muscles.

Fig. 412

C altered ellisi

(Osburn).

FAMILY 4. BICELLAEIIDAE.

Colony erect and branching; zooecia obliquely placed in 2 or more
rows and conical or rectangular; stalked avicularia usually present and
no vibracula; ooecia at the upper end of the zooecia: 16 genera.

1. Bi CELL ARIA Blainville. Zooecia cornucopia-shaped, loosely joined
together and directed obliquely sideways: about 15 species.

254

BRTOZOA

B. ciliata (L.) (Fig. 413). Colony forming feathery tufts 12 mm.
high, white in color; zocecium with 4 to 7 very long slender spines along
its upper margin : Atlantic coast, on hydroids and algae ; Europe.

2. BTTGTJLA Oken. Zocecia more or less quadrangular,
arranged in 2 or more rows; opening large, not oblique;
avicularia in form of a bird's head: about 35 species, 9
on the Atlantic coast, 8 on the Pacific.

Key to the species of Bugula here described:

Oj Zocecia in 2 rows B. TURBITA

a2 Zocecia in 3 or more rows.

bt Avicularia not at base of aperture B. FLABELLATA

&2 Avicularia at base of aperture B. MUREAYAN A

Fig. 413
Bicellaria

ciliata
(Osburn).

Fig. 414

Bugula

flabellata

(Osburn).

1, ooecium

2, avicularium

B. turrita (Desor). Colony up to 30 cm. or more in height, com-
posed of flat branches growing in spirals, each branch with 2 rows of
zooecia, each zooecium with a spine on the outer upper angle ; color yellow :
North Carolina to Casco Bay, very common in shallow water.

B. flabellata (Thompson) (Fig. 414). Colony up to 25
mm. high, composed of broad flat branches, each with from
3 to 7 rows of zooecia, each upper angle with 2 spines; of
an ashy color when dried, flesh color when alive : Vineyard
Sound and northwards in shallow water; common; Pacific
coast; cosmopolitan.

B. murrayana (Johnston). Colony a bushy tuft up
to 50 mm. high and like the above, with 3 to 12 rows of
zofficia; each upper angle with a stout erect spine and
1 to 5 long slender spines on each lateral margin; long
clasping fibers present; ocecia with radiating striae; straw color when
dry: circumpolar, south to Vineyard Sound in rather deep water;
Europe; Pacific coast.

FAMILY 5. CELLABIIDAE.

Colony erect, slender, cylindrical, calcareous, usually dichotomously
branching and jointed; zocecia in 1 or more rows, lozenge-shaped or hex-
agonal and arranged in series around a central axis, making the branch
cylindrical: 8 genera.

CELLARIA Lamouroux. Colony jointed, the internodes connected by
flexible horny tubes; zooecia surrounded by a raised border; avicularia
of simple type, resembling the ordinary zooecium; ocecia concealed, the
opening being just above the mouth : several species.

0. fistulosa (L.) (Fig. 415). Shape of zooecium variable; orifice
arched above, slightly incurved below; area surrounding it minutely
pitted; avicularium just above it and in the same line with the zooecium;

BRTOZOA

255

opening of ooecium round or oval: a northern species; on rocks, shells,
etc., from shallow to deep water.

FAMILY 6. FLUSTRIDAE.

Colony horn-like and flexible, erect, expanded, and foliaceous, usually
consisting of broad branches attached by a narrow base; zooecia contigu-
ous and multiserial : 6 genera.

FLTTSTRA L. Colony frond-like ; zooecia in 1 or 2 layers, more or less
quadrangular in form, rounded above, with a raised margin; avicularia

Fig. 415

Fig. 416

Fig. 417

Fig. 415 — Cellaria flstulosa (Cambridge Natural History). Fig. 416 — Flustra foliacea

(Cambridge Natural History). A, entire colony ; B, several zooids.

Fig. 417 — Membranipora pilosa (Osburn).

resembling the zooecium and usually in line with them; ooecia concealed:
several species.

F. foliacea (L.) (Fig. 416). Colony brownish in color, with a dis-
tinct odor of violets when fresh, up to 15 cm. high; zooecia in rows and
in 2 layers with 2 spines on a side; ooecia very shallow, the opening
forming an arch over the upper end of the zooecium: a northern species
occurring on stones, shells, etc., in shallow water.

FAMILY 7. MEMBKANIPOEIDAE.

Colony calcareous or partly membranous and flattened, being in-
crusted on stones, shells, or seaweed, occasionally erect; zooecia often more
or less rectangular and with raised margins : several genera, with 150 species.

MEMBRANIPORA Blainville. Zooecia with raised margins and a
depressed front wall which is wholly or partly membranous, and placed
beside one another horizontally, forming a more or less irregular crust : 12
species near Woods Hole.

M. pilosa (L.) (Fig. 417). Zooecia ovate, narrowed below, thickly
punctured with minute oval pores and often with a silvery sheen; margin
thickened, with 4 to 12 spines and just below it a corneous spine, some-
times short anc] sometimes very long; no ooecia; on stones, etc., frpm tide

256 BRTOZOA

lines to deep water, from Long Island Sound to the Arctic Ocean; very
common; cosmopolitan.

M. monostachys Busk. Colony irregular, often radiate; zooecia oval
and elongate, with usually 6 to 10 pairs of marginal spines, of which the
upper pair is directed upwards and the others bend inwards, often meet-
ing in the middle; a single large basal spine is directed forwards and
may be the only spine present; avicularia wanting; ooecia wanting: on
stones, shells, seaweed, etc., from shallow to deep water; New Jersey to
the Arctic Ocean; cosmopolitan.

M. craticula Alder. Zooecia small, in regular radiating linear rows,
oval; margin with about 14 flattish spines, of which the upper 2 are
erect; the others extend across the cell, meeting in the middle of it; an
avicularium often at the margin of the cell: on shells, etc., the colony
forming small flabellate or roundish patches with a spongy appearance;
from shallow to deep water; Arctic Ocean to Long Island Sound.

FAMILY 8. CEIBEILINIDAE.

Colony incrusting or erect; zocecia with the front wall more or less
fissured or traversed by radiating furrows : 6 genera.

CRIBRILINA Gray. Colony incrusting; zocecia contiguous; opening
semicircular: about 20 species.

C. punctata (Hassall). Zooacia oval, covered with small punctures,
often arranged in rows; 4 or 5 marginal spines with usually an avicu-
larium on each side of the orifice ; ocecia rounded : Vineyard Sound and
northwards ; in shallow water ; common on shells and pebbles ; Europe.

C. annulata (Fabricius) (Fig. 418). Zooecia ovate, convex, very
distinct, with a median keel and about 6 transverse rows of punctured
furrows; sometimes with 3 or 4 marginal spines; colony forming small
reddish crusts: on stones and kelp, from shallow to deep water; often
common north of Cape Cod; Europe.

FAMILY 9. MICEOPORELLIDAE.

Colony either incrusting or erect and foliaceous or dendritic; orifice
more or less circular and with a straight lower margin and a semilunate
or circular median pore immediately below it : 3 genera.

MICROFORELLA Hincks. Colony incrusting; orifice semicircular:
several species.

M. ciliata (Pallas) (Fig. 419). Colony forming a delicate, irregular
crust with a frosty sheen on seaweed, shells, etc.; zooecia obscurely hex-
agonal and punctate; orifice bearing 3 to 7 long spines, which may be
wanting; median pore lunate; large avicularium on one side with an acute

BETOZOA 257

mandible often prolonged into a long, slender spine; ooecia globose, above
the zooBcium: cosmopolitan; from tide lines to 300 fathoms.

FAMILY 10. MYEIOZOIDAE.

Colony incrusting or rising in a foliaceous or dendroid expansion;
zooecia calcareous without raised margins or membranous area; opening
with an indentation in the lower lip: 5 genera.

SCHIZOPORELLA Hincks. Colony incrusting, sometimes several lay-
ers thick, or occasionally forming foliaceous expansions; avicularia
usually lateral: over 100 species.

S. unicornis (Johnston) (Fig. 420). Zooecia ovate or rectangular
with a punctate surface, often silvery in appearance, an avicularium on
one or both sides of the opening; orifice circular; ooacia globose, with

Fig. 418 Fig. 419 Fig. 420

Fig. 418 — Cribrilina annulata (Osburn). Fig. 419 — Microporella ciliata (Osburn).
Fig. 420 — Schizoporella unicornis (Osburn).

radiating grooves ; colony forms a white or reddish spreading crust : South
Carolina to Massachusetts Bay; from tide lines to deep water, on shells,
stones, etc.; often very common; Europe.

S. hyalina (L.). Zooecia elliptical, arranged irregularly in radiating
rows; surface smooth and shiny, often glassy and transparent; opening
terminal variable in shape, sometimes without the indentation; ooecia
globose and punctate: Long Island Sound to the Arctic Ocean from tide
lines to deep water ; on stones, etc., and often forming nodules on hydroids ;
cosmopolitan ; California.

FAMILY 11. ESCHAEIDAE.

Colony calcareous and incrusting, or erect, being lamellate or den-
dritic; zooecia without raised margins or membranous area; sometimes
with secondary opening, either elevated and enclosing an avicularium or
not: numerous genera.

1. LEPRALIA Johnston. Zooecia usually ovate, with a more or less
horseshoe-shaped orifice which is arched above and straight and often
narrow below; colony incrusting or foliaceous, often radiating from a
central point: about 70 species.

258

BEYOZOA

Fig. 421

Lepralia

pallasiana

(Osburn).

L. pallasiana (Moll) (Fig. 421). Zocecia large and coarsely punc-
tate; orifice large, contracted on each side below the middle, often with
an avicularium below the lower border; peristome raised and prominent;
no ooecia ; colonies forming large, reddish crusts : common ;
New Jersey to the Arctic Ocean, between tide lines and in
shallow water.

L. pertusa (Esper). Zocecia large, swollen, punctate;
orifice round, contracted below by 2 lateral denticles, with
usually a tubercle below it; ooecia globose: Gulf of St.
Lawrence to Florida, on shells, etc., from shallow to deep
water; colored patches radiating from a common center;
Europe.

2. PORELLA Gray. Zooecia ovate or elongate, with a
semicircular orifice, above which is a secondary orifice,
this being elongate or more or less triangular and enclos-
ing an avicularium ; colony incrusting or erect and f oliaceous.

P. concinna (Busk). Zocecia granular, arranged in lines; orifice
arched above, with 2 spines, frequently with a raised margin ; avicularium on
lower lip; ooecia globose, prominent, often with a puncture
in front : Cape Cod to Gulf of St. Lawrence, colony form-
ing large circular reddish patches; Europe; California.

3. SMITTINA Norman. Zocecia more or less quad-
rangular, with a small circular orifice which is surrounded
by an elevated ridge or peristome; primary orifice dentate,
secondary orifice with a sinus in front ; colony incrusting or
erect and f oliaceous: numerous species.

S. trispinosa (Johnston) (Fig. 422). Zooecia ovate,
very variable; orifice variable, usually round or pear-
shaped, often being narrowed below, with 2 to 4 spines on young indi-
viduals, frequently with a large avicularium at one side, occasionally
with 1 or 2 small oval avicularia; ooecia large, globose, usually with
2 or 3 punctures: Atlantic coast, colonies forming large
yellow or whitish crusts; Europe; Pacific coast.

4. MUCRONELLA Hincks. Zooecia with a semicir-
cular or reniform opening, the margin being elevated in
front and with a prominent tooth below: colony in-
crusting; about 50 species.

M. peachi (Johnston) (Fig. 423). Zooecia rhom-
boidal; opening large, with 6 slender marginal spines
which may be wanting in old individuals; ooecia small:
Long Island Sound to the Arctic Ocean, from tide lines to deep water,
colony forming a large whitish irregular patch of solid texture; Europe.

Fig. 422
Smittina
trispinosa
(Osburn).

BRYOZOA 259

FAMILY 12. CELLEPORIDAE.

Zocecia calcareous, tubular, more or less erect, with a terminal open-
ing, and irregularly heaped together; colony usually incrusting, often
composed of many layers of cells; sometimes erect: 2 genera.

CELLEPORA Fabricius. With the characters of the family: numer-
ous species.

C. americana Osburn. Colony incrusting or rising in nodular
branches a few millimeters high, growing on hydroid and bryozoan stems
and algae; zooecia ovate, more or less erect, heaped upon one another and
turned in various directions; orifice circular with a notch and a rostrum
which overhangs it and an avieularium at its base: Long Island to Arctic
Ocean ; often common.

C. pumicosa (L.). Colony massive, scabrous, composed of many lay-
ers of pinkish color when fresh ; zooecia subcylindrical or ovate, smooth,
erect, crowded; orifice round, with a thin, raised margin, immediately
below which a tall rostrum bearing an avicularium is often present:
Atlantic and Pacific coasts, covering stones and shells in shallow
water; common.

SUBORDER 3. CTENOSTOMATA.

Opening terminal and closed by an operculum of setae set in a
thin membrane; zooecium never calcareous but fleshy or membranous;
no avicularia, vibracula, or ococia: 11 families, 10 of which are marine.

Key to the families of Ctenostomata here described:

»! Animals marine.
&! Colony fleshy, forming irregular, incrusting or erect masses.

Ci Opening of zooacium not bilabiate 1. ALCYONIDIIDAE

c2 Opening with 2 distinct lips 2. FLUSTBELLIDAE

Z>2 Colony branching, either recumbent or erect.

G! All the tentacles erect, forming a circle 3. VESICULABITDAE

ca Tentacles not in a circle, 2 being turned back 4. VALKERIIDAE

a.. Animals in fresh water 5. PALUDICELLIDAE

FAMILY 1. ALCYONIDIIDAE.

Colony fleshy or membranous, forming either an expanded and gelat-
inous crust on seaweed or rocks, or being erect and cylindrical or com-
pressed; zocecia closely joined and developing by budding from one
another and not from a stolon; opening closed by an invagination of the
tentacular sheath: 1 genus.

ALCYONIDIUM Lamouroux. With the characters of the family: 18
species.

A. mytili Dalyell. Colony an extensive gelatinous crust, cylindrical
or somewhat flattened, and irregular in shape and reddish, gray, or yel-

260 BRTOZOA

lowish in color ; zooecia hexagonal, closely packed together : from the Arctic
Ocean south to Long Island Sound, on stones, piles, crabs, etc., from tide
lines to deep water; Europe.

A. hirsutum (Fleming) (Fig. 424). Colony incrusting or erect, com-
pressed, expanded, and branched, yellowish-brown or reddish in color,
the surface covered with conical papilla, between which are the orifices :
Long Island Sound to Arctic Ocean in shallow water, incrusting the
stems of f ucus and other plants ; common ; Europe.

FAMILY 2. FLUSTKELLIDAE.

Colony similar to the above, but the opening is bilabiate, with a
movable lip which acts as an operculum; larva (Cyphonautes) with a
bivalve shell: 1 genus.

FLUSTRELLA Gray. With the characters of the family : 3 species.

F. hispida (Fabricius) (Fig. 425). Colony a thick, brown crust,
roughened by numerous reddish spines; zooecium ovate or hexagonal, with

Fig. 424 Fig. 425 Fig. 426

Fig. 424 — Alcyonidium hirsutum (Osburn). Fig. 425 — Flustrella liispida (Osburn).
Fig. 426 — Bowerbankia graoilis (Osburn).

a raised opening around which are one or more tall, red spines, which may
also be present along the margin of the cells: circumpolar, south to
Long Island Sound and Alaska, incrusting the stems of fucus, etc.;
common; Europe.

FAMILY 3. VESICULAEIIDAE.

Colony horn-like or membranous, branching, and either erect or recum-
bent, the zooecia contracted below, budding off from a distinct stem:
5 genera.

1. BOWERBANKIA Farre. Colony recumbent; zooecia cylindrical, in
clusters often spirally arranged; 8 to 10 tentacles in a circle; gizzard
present between stomach and oesophagus: 20 species.

B. gracilis Leidy (Fig. 426). Colony creeping, the cylindrical zooids
rising separately from the recumbent stem: coast of New England, on
hydroids, seaweed, etc.

2. AMATHIA Lamouroux. Colony erect; zooids in a double series:
several species.

BEYOZOA 261

A. dichotoma (Verrill) (Fig. 427). Colony 5 cm. or more high and
white in color, repeatedly forking, a short, dark-brown segment being
at the base of each fork; zooids crowded together spirally in groups of
6 to 12 each: New Jersey northwards, on algae, rocks, etc., in shallow
water; often common.

FAMILY 4. VALKEEIIDAE.

Colony branching and erect or recumbent and creeping; tentacles
8 in number, 2 of which are bent outwards towards the side and 6 are
erect; zooecia contracted below: 1 genus.

VALKERIA Fleming. With the characters of the family: 4 species.

Fig. 427 Fig. 428 Fig. 429

Fig. 427 — Amathia dichotoma (Osburn). Fig. 428 — Valkeria uva (Osburn)
Fig. 429 — Paludicella ehrenbergi.

V. uva (L.) (Fig. 428). Colony composed of delicate jointed tubes,
which creep over seaweed, hydroids, or shells, or may stand erect to a
height of 5 to 10 cm. giving off paired branches ; zooids in thick clusters,
which are principally at the base of the branches atfd on them: from
New Jersey northwards, in shallow water; Europe.

FAMILY 5. PALUDICELLIDAE.*

Colony with a horn-like or membranous cuticula and composed of
delicate, jointed, branching, recumbent or partly erect tubes, which creep
over stones and sticks in slow streams and fresh-water ponds : 2 genera.

Key to the genera of Paludicellidae :

Oi Zooids recumbent, not rising from stolons - 1. PALUDICELLA

a2 Zooids erect, rising from stolons 2. POTTSIELLA

1. PALUDICELLA Gervais. Colony consists of series of club-shaped
zooids placed end to end and separated from one another by partitions ;
opening lateral; branches usually paired; no statoblasts present but
hibernacula or winter buds which persist when the rest of the colony
has died: 1 species.

P. ehrenbergi van Beneden (Fig. 429). Colony recumbent or partly
erect ; length of zooid 2 mm. ; number of tentacles about 16 : cosmopolitan.

* See "Observations on Budding in Paludicella and Some Other Bryozoa," by
C. B. Davenport, Bull. Mus. Comp. Zool., Vol. 22, 1890.

262 SRTOZOA

2. POTTSIELLA Kraepelin. Colony consists of stolons from which
at intervals single erect, cylindrical zooids arise; opening terminal: 1
species.

P. erecta* (Potts). Length of zooid 1.5 mm.; number of tentacles
about 20: Montgomery County, Pennsylvania.

ORDER 2. PHYLACTOL^GMATA.f

Lophophore oval or horseshoe-shaped; epistome present, projecting
over the mouth; statoblasts present, which usually have a broad mar-
ginal band of air cells called the float which sustains them in the water:
in fresh water; 3 families and about 30 species, 7 American.

Key to the families of Phylactolcemata :

G! Colony branched, provided with an opaque chitinous or hyaline cuticula ;

statoblasts without hooks.

Z>! Lophophore nearly circular; statoblasts without float.. 1. FREDEKICELLIDAE
~ba Lophophore horseshoe-shaped ; statoblasts with float .... 2. PLUMATELLIDAE
aa Colony massive, secreting a gelatinous base; statoblasts with float and

hooks 3. CKISTATELLIDAE

FAMILY 1. FREDERICELLIDAE.

Colony tubular, branched in form of antlers; lophophore oval;
cuticula opaque and brown, rarely gelatinous and hyaline; tentacles not
over 24; statoblasts dark brown, elliptical, with-
out float : 1 genus.

1. FREDERICELLA Gervais. Colony dendritic
and either recumbent or erect, attached either
entirely or partially to the under surface of
stones or sticks in ponds and streams, usually in
dark places; lophophore oval, bearing usually 20

Kig. 430

Fredericeila sultana. to 22 tentacles: 1 American species.
A, colony (Davenport). _ .. ,_., . . . ,_ . .. TT

B, statobiast F. sultana (Blumenbach) (F. walcottn Hyatt;

(Siissw. F. Deut.). _ _ _ TT _ ._.... ,„..

F. pulchernma Hyatt; F. regina Leidy) (Fig.

430). Form of colony differs in different localities, consisting of inter-
twining branches which adhere to the substratum or form a dense clump :
cosmopolitan.

FAMILY 2. PLUMATELLIDAE.

Colony consists either of cylindrical tubes which are either branched
or form massive clumps or of hyaline, recumbent, lobed tubes, or of
hyaline erect, slightly lobed sacs ; tentacles 40 to 60 on a horseshoe-shaped

* See "On Paludicella erecta," by E. Potts, Proc. Acad. Nat. Sci., 1884, p. 213.
t See "Observations on Polyzoa, Suborder Phylactolsemata," by A. Hyatt, Proc.
Essex Inst., Vols. 4 and 5, 1866-1868.

BRYOZOA

263

lophophore ; statoblasts elliptical, without marginal hooks but with a float :
several genera.

Key to the genera of Plumatellidae here described :

Oj Statoblasts oval ; zooids uniformly spaced 1. PLUMATELLA

Oj Statoblasts lenticular ; zooids grouped at intervals 2. LOPHOPUS

1. PLUMATELLA Lamarck. Colony consists of cylindrical, more or
less branched tubes, either recumbent or erect, which lie extended on
the substratum or form a clump ; 40 to 60 tentacles : about 20 species, 3
American ; in ponds and streams, usually not in the light ; the commonest
fresh-water bryozoans.

P. princeps Kraepelin (P. diffusa Leidy) (Fig. 431). Colony creep-
ing or erect, often much branched, the branches sometimes fused to-

Fig. 431

Fig. 432

Fig. 431 — Plumatella princeps. A, a colony (Davenport) ; B, a floating statoblast;
C, a stationary statoblast (Siissw. F. Deut.). Fig. 432 — Plumatella polymorpha.
A. a colony (Davenport); B, a floating statoblast; C, a stationary statoblast
(Siissw. F. Deut.).

gether; cuticula brown, with a keel that broadens at the aperture;
statoblast elongated: cosmopolitan.

P. polymorpha Kraep. (P. nitida Leidy; P. arethusa Hyatt) (Fig.
432). Colony creeping or erect, often richly branched; cuticula usually
transparent, rarely brown or keeled ; statoblast nearly
circular, sometimes with angular margin: cosmopol-
itan.

P. punctata Hancock (P. vesicularis Leidy; P.
vitrea Hyatt) (Fig. 433). Colony creeping, often
thickly branched; cuticula colorless, transparent, the
elevated mouth cone being wrinkled and spotted with
white; statoblast nearly circular: in America and
Europe.

2. LOPHOPUS Dumortier. Colony thick, erect,
and sometimes lobed; cuticula gelatinous; about 60 tentacles; statoblast
with acute ends; 1 American species.

L. cristallinus (Pallas) (Fig. 434). Colony up to 10 mm. long: in
ponds and slowly-flowing streams, chiefly on water plants; rare; America
and Europe.

Fig. 433 Fig. 434

Fig. 433 — Stato-
blast of Plumatella
punctata (Siissw. F.
Deut). Fig. 434—
Statoblast of Lopho-
pus crystallinus
(Siissw. F. Deut.).

264

BEYOZOA

FAMILY 3. CEISTATELLIDAE.

Colonies forming compact hyaline groups which secrete a gelatinous
base; aperture slightly elevated above the level of the group; statoblasts
large, about 1 mm. in diameter, provided with hooks : 2 genera.

Key to the genera of Cristatellidae:

Oi Statoblast with a row of marginal hooks; gelatinous base often very

thick 1. PECTINATELLA

at Statoblast with 2 rows of marginal hooks ; gelatinous base forms a thin

sole 2. CBISTATELLA

1. PECTINATELLA Leidy. Many associated colonies in rosette-shaped
groups on a gelatinous base which may attain a
thickness in the autumn of 40 cm.; the youthful
colony is locomotory: 1 American species.

P. magnifica Leidy (Fig. 435). Tentacles 60 to
84 in number; statoblasts circular, black in color,
with 10 to 22 marginal anchor-shaped hooks: often
common on stones, sticks, etc., in ponds and streams;
North America; introduced locally into Europe and
Japan.

2. CRISTATELLA Cuvier. Colony an elongate,
gelatinous mass with a thin, flat sole on which it
creeps; the zooids are located on the upper surface
of the colony and may contract into a common cavity;
statoblasts circular with 2 rows of marginal hooks: 1
species.

0. mucedo Cuv. (C. idae Leidy; C. ophidioidea Hyatt;
C. lacustris Potts) (Fig. 436). Young colony circular,
later elongate, attaining in the autumn a length of 28
cm. ; usual length 3 to 5 cm. ; 80 to 90 tentacles ; statoblasts
with 10 to 34 hooks in one row and 20 to 50 in the other:
America and Europe, in ponds and sluggish streams on submerged sticks1,,
pond lily leaves, etc.; not common.

Fig. 435— Pectina-
tella magnifica (Dav-
enport). A, a thick
gelatinous mass sur-
rounding a stick on
which are numerous
colonies ; B, stato-
blast.

Fig. 43&

Statoblast of

Cristatella

muced')

(Siissw. F..

Deut.).

SUBPHYLUM 5. BRACHIOPODA.*

Sessile, marine, mollusk-like animals in which the body is enclosed
in a bivalve, calcareous, or horny shell, one valve of which is dorsal and
one valve ventral. The shells (Fig. 437) can be opened and closed by
means of muscles, the hinge end being posterior and the opening anterior

* See "Catalogue of the Recent Species of the Class Bracbiopoda," by W. H. Dall,.
Proc. Acad. Nat. Sci., Phil., 1873, p. 177. "A Monograph of Recent Brachiopoda," by
T. Davidson, Trans. Lin. Soc., 2nd ser., Vol. 4, 1886-1888. "Revision of the Families;
of Loop-bearing Brachiopoda," by C. E. Beecher, Trans. Conn. Acad., Vol. 9, 1893..

BRACHIOPODA 265

in position. The animal is attached to some more or less fixed object by
means of the peduncle, a stout, muscular stalk which is a prolongation of
the hinder end of the body and passes either between the valves of the
shell or through a hole in the projecting ventral valve; in a few species
(Crania) the whole ventral valve is attached, no peduncle being present.
The soft parts of the body, which lie between the hinder land middle
portions of these shells, are very short and broad, and from them two
leaf -like folds called the dorsal and the ventral mantles extend forwards
and cover the inner surface of the forward portion of the shells. Two
additional projections of the anterior body wall also extend forwards and
occupy the space between the two mantles. These are the tentacular arms
<>r lophophores, a pair of ridges or of bent or coiled arms which in the

Fig. 437 — Diagram of a brachiopod (Delage et HSrouard). 1, peduncle; 2, dorsal

shell ; 3, stomach ; 4, liver ducts ; 5, mouth ; 6, mantle ; 7, gills ;

8, lophophore ; 9, muscles ; 10, intestine ; 11, ventral shell.

Testicardines are supported by a calcareous skeleton proceeding from the
dorsal valve of the shell. These arms are the largest and most conspicuous
organs in the body and have given the group its name : they are respiratory
and sensory in function, and are also of use in the ingestion of food.
Both they and the mantles contain a cavity which is in direct communi-
cation with the body cavity. Running along the surface of each ridge or
arm is a ciliated groove along one side of which is a row of ciliated ten-
tacles. By the action of these cilia the minute organisms which form the
food of the animal are swept into the mouth.

The mouth lies between the base of the arms and is without special
jaws or lips; it opens into a digestive tube in which an oesophagus, stom-
ach, and intestine may be distinguished. Sac-like digestive glands (livers)
open into the stomach. The Testicardines have no anus: in the Ecardines

266 BRACHIOPODA

the anus is at the hinder end of the body between the edges of the shells.
The nervous system consists of a pair of ganglia dorsal to the oesophagus,
a ventral pair, connecting commissures and radiating nerves. There are
no special sense organs in the adult animal, although the larva may have
eye spots and otocysts. The circulatory system consists of a heart, a large
vein which enters it anteriorly, and arteries which proceed to the spaces
of the body cavity. The excretory organs consist of a pair (two pairs in
Rhynchonella) of nephridial tubes which open into the body cavity at one
end and into the mantle cavity at the other. The sexes are as a rule sep-
arate. The two pairs of genital glands lie near the intestine and discharge
their products into the body cavity, whence they find their way to the
outside through the nephridia. The larva is a trochophore, and is made
up of three divisions, from the middle one of which the mantle folds
develop: after a few hours of free life the larva attaches itself.

Habits and Distribution.*— All Brachiopoda are attached to rocks, or
other similar objects, except the Lingulidae, which live in vertical burrows
in the sand. Most of the species live in shallow water in the neighbor-
hood of continents : a few, however, are found in the deep sea. They are
not generally distributed over the world but are localized, as is the case
with many ancient groups of animals, but are often found in large num-
bers where they do occur. Brachiopods have flourished during all the
geological ages from the Cambrian down to the present time, the genus
Lingula, which is still plentiful in the Indian and Pacific Oceans, being
the oldest known genus of animals. About 2,500 fossil species have been
discovered, mostly in the Paleozoic rocks, only about 120 living species
being known.

History.]— The conspicuous shells of the Brachiopoda attracted the
attention of the older naturalists, by whom the animals were almost uni-
versally regarded as mollusks. The name Brachiopoda was given them
in 1807 by Dumeril. In 1873 and 1874 Morse and Kowalevsky independ-
ently demonstrated by a study of their embryology that the affinities of
brachiopods were not with the Mollusca but rather with the Annelida.
Brooks held them to be Bryozoa, while Huxley and Claus placed them
among the Molluscoidea, a subkingdom or phylum originally created by
Milne-Edwards to contain the Bryozoa and Tunicata. Conklin and others

* See "Observations on Living Brachiopoda," by E. S. Morse, Mem. Bost. Soc.
Nat. Hist., Vol. 5, 1902.

t See "On the Embryology of Terebratulina," by E. S. Morse, Mem. Bost. Soc.
Nat. Hist, Vol. 2, 1873. "On the Systematic Position of the Brachiopoda," by E. S.
Morse, Proc. Bost. Soc. Nat. Hist., Vol. 15, 1873. "On the Development of the
Brachiopoda," by A. Kowalevsky, Abst., by A. Agassiz, Am. Jour. Sci., 1874. "Th«
Development of Lingula and the Systematic Position of the Brachiopoda," by W. K.
Brooks, Sci. Results of Sess. of 1878, Chesapeake Zool. Lab. "The Embryology of
a Brachiopod," etc., by E. G. Conklin, Proc. Am. Phil. Soc., Vol. 41, 1902.

BRACHIOPODA 267

quite recently have shown the relationship between the Brachiopoda and
Phoronis. The affinities of the Brachiopoda are thus still obscure, but
are undoubtedly with the Bryozoa and Phoronis.

The subphylum contains 2 orders.

Key to the orders of Brachiopoda:

a: Shell without a hinge joining the valves 1. ECABDINES

o2 The valves of the shell joined by a hinge 2. TESTICABDINES

ORDER 1. ECARDINES.

Shell horn-like or calcareous, the valves not being joined posteriorly by
a hinge but only by muscles; mantles also not joined; no calcareous arms
projecting from the dorsal valve to support the tentacular arms; anus
present: 3 families with about 32 living and 400 fossil species, most of
the latter being Paleozoic.

Key to the families of Ecardines here described :

G! Peduncle present ; animal living in sand 1. LINGULIDAE

o2 Peduncle not present; animal attached by ventral valve 2. CBANIIDAE

FAMILY 1. LINGULIDAE.

Shell more or less rectangular in shape, horn-like in texture, with
valves of equal size, truncated in front and pointed behind; peduncle con-
tractile and usually long; tentacular arms spiral, with about 6 whorls;
mantle very vascular, with long stiff setae on the edges: 16 species, in
2 genera, of which Lingula is found in the Pacific and Indian Oceans and
Glottidia on both shores of America; 100 fossil species.

GLOTTIDIA Ball. Shell smooth and linguiform;
dorsal valve with 2 internal, sharp, incurved laminae
diverging from the beak and extending a third of the
length of the shell; ventral valve, with a mesial septum
extending forwards from the beak: about 4 species, on
both Atlantic and Pacific coasts of America.

G. albida (Hinds). Shell narrow, oval, tapering
at the beak, very slightly curved in front, smooth, and
white; peduncle stout and short, 45 mm. long; shell 30
mm. long: Pacific coast from San Diego to Monterey, from low- water
mark to 60 fathoms.

G. audebarti* (Broderip) (Lingula pyramidata Stimpson) (Fig. 438).
Shell narrow, tapering at the back, front margin nearly straight; color
white, with transverse bands of green; peduncle very long and slender;
animal hermaphroditic; length of shell 27 mm., breadth 10 mm.; length

* See "A Study of the Structure of Lingula (Glottidia) pyramidata Stimp.," by
H. E. Beyer, Stud. Biol. Lab., Johns Hopk., Vol. 3, 1886.

268 BRACHIOPODA

of peduncle 16 cm.: North Carolina to Florida; in vertical burrows in
the sand between tide lines, the contractile peduncle extending straight
down and the opening of the shell just reaching the water.

FAMILY 2. CEANIIDAE.

Shell more or less quadrate or circular in shape and without a
peduncle, being attached by the ventral valve to a rock; dorsal valve
limpet-like; tentacular arms free and spiral; mantle extending to the
edges of the valve, its margin being plain : 1 genus.

CRANIA Retzius. Shell smooth or radiately striated: 4 species.

C. anomala (0. F. Miiller). Shell brownish in color, 18 mm. long
and 22 mm. broad: Florida Keys and the West Indies, in 100 fathoms.

ORDER 2. TESTICARDINES.

Shell calcareous, the 2 valves being joined by a hinge; mantles also
fused behind; ventral valve larger than the dorsal and with a beak at
the hinder end through which the peduncle passes; tentacular arms
supported by calcareous arms which proceed from the dorsal valve ; anus
wanting: 3 families and about 80 species; about 2,200 fossil species.

Key to the families of Testicardines here described :

Oj Shell with a sharp, hook-like beak 1. RHYNCHONELLIDAE

a2 Beak not hook-like, but prominent 2. TEKEBRATULIDAE

FAMILY 1. EHYNCHONELLIDAE.

Shell more or less triangular with a sharp, hook-like beak; calcareous
arms long and slender, curving towards each other; tentacular arms
long and spiral: 2 genera and 8 species.

RHYNCHONELLA Fischer. Shell with radiating ridges; dorsal valve
very convex, ventral valve more flattened: 6 species.

R. psittacea (Gmelin). Shell brown or black, 26 mm. long and not
quite so wide: circumpolar, being found south to the Gulf of St. Law-
rence and to the Aleutian Islands, in shallow water.

FAMILY 2. TEREBEATULIDAE.

Shell round or oval, the lower valve with a prominent perforated
beak and 2 curved hinge teeth, dorsal valve with a hinge process and a
slender calcareous loop: about 10 genera and 68 species.

Key to the genera of Terebratulidae here described :

Oj. Calcareous loop short 1. TEREBRATULINA

o2 Calcareous loop long.
&! Loop with its principal stem attached but once 2. WALDEHEIMIA

62 Principal stem attached twice 3. TEREBRATELLA

63 Reflected part of loop attached at the tip 4. LAQUEUS

BEACHIOPODA

269

Fig. 439 — Tere-
bratulina septen-
trionalis (Tryon).

A, dorsal aspect ;

B, inner surface
of dorsal shell,
showing calcare-
ous arms.

1. TEREBRATULINA D'Orbigny. Shell punctate, with 5 radiating
striations; calcareous loop short and forming either a perfect or a
broken ring: 8 species; 22 fossil species.

T. septentrionalis (Couthouy) (Fig. 439). Shell
thin and semi-transparent, yellowish or whitish, broadly
oval; beak projecting but little, truncated horizontally,
with a large orifice; 13 mm. long and 8 mm. broad:
coast of New England, in 20 fathoms off Cape Cod, at
low-water line farther north; common.

T. caput-serpentis (L.). Shell oval, whitish or
yellowish; 25 mm. long; 17 mm. wide: Europe; Florida
and the West Indies (var. cailleti) ; Pacific coast from
San Diego to Aleutian islands (var. unginculata) .

2. WALDHEIMIA King. Shell globose and smooth,
calcareous loop composed of 2 slender branches which
extend from the hinge almost to the front edge of the

shell, then curve backwards to the center, where they join: 10 species;
90 fossil species.

W. floridana Pourtales. Shell triangular, gray or
brownish-white in color; length 22 mm.; width 25 mm.;
depth 14 mm. : Florida reefs and the West Indies, in 100
to 200 fathoms; abundant.

3. TEREBRATELLA D 'Orbigny. Shell ovoid or round ;
loop long and like Waldhelmia, but with its principal
stem twice attached: 9 species.

T. transversa (Sowerby) (Fig. 440). Shell variable
in shape, usualty wider than long; length 30 mm.;
breadth 38 mm.; depth 20 mm.; color from light yellow
to dark purple: Monterey, California, northwards, in 15
to 20 fathoms, the commonest brachiopod on the coast.
T. spitzbergensis Davidson. Shell whitish-yellow and longer than
wide; valves equally convex, smooth, and strongly punctate; length 9
mm.; breadth 7 mm.; depth 3.5 mm.: circumpolar;
south to Gulf of St. Lawrence, in 40 to 400 fathoms.
4. LAQUEUS Dall. Shell broadly ovoid; loop
long like Terebratella, but with the reflected portion
attached by a connecting branch on each side to the
principal stem: 3 species.

L. californicus (Koch) (Fig. 441). Shell 6 cm.
long, 5 cm. broad, and 25 mm. deep; bright yellowish or reddish-brown
in color : Santa Barbara County, California, and northwards, in 90 fathoms,
being smaller towards the north.

Fig. 440 — Tere-
bratella trans-
versa (Keep).
A, natural posi-
tion, with the
dorsal shell
uppermost ; B,
dorsal aspect.

Fig. 441

Laqueus californicus
(Keep).

270

PHORONIDEA

SUBPHYLUM 6. PHORONIDEA.*

Sessile, marine worms living in chitinous tubes in shallow water, which
have at the anterior end of the body a horseshoe-shaped tentacular crown
or lophophore. The animals are gregareous, their tubes being often
twisted together, but without, however, communicating with one another.
The tubes are also covered with sand, pieces of shell, etc., which give them
a characteristic appearance. The lophophore consists of a double ridge,
each part of which bears a single row of tentacles, its lateral extremities
forming a spiral coil on each side. The mouth and the anus are near
together in the middle of the lophophore, but are
separated by a long projection of the body wall
called the epistome. Near the anus are the paired
orifices of the kidneys. The body cavity is large and
is divided by a diaphragm into two parts, an upper
or anterior, which is continuous with the cavities of
the epistome and the tentacles, and a lower, which
contains the viscera: the diaphragm is pierced by
blood vessels and the oesophagus. The digestive tract
is U-shaped, consisting of the oesophagus, stomach,
and intestine, and is supported by longitudinal mesen-
teries. Two circulatory fluids are present, a colorless
fluid in the body cavity and a red fluid in a system
of closed vessels which lie along the two limbs of the
digestive tube and are distributed to the tentacles
and other organs. The kidneys are a pair of tubes
which communicate between the body cavity and the
outside. The nervous system is subepithelial in posi-
tion and consists of a nerve ring surrounding the mouth and nerves
going from it to the tentacles. The animals are hermaphroditic, the
gonads lying near the stomach and discharging their products into the
coelom, whence they find their way to the outside through the kidney
pores. The development is a metamorphosis, the characteristic larva
being known as the actinotrocha.

The systematic position of the animals has long been a matter of
dispute, but they are now usually placed near the Bryozoa and Brachio-
poda. The subphylum contains a single genus and about a dozen species,
of which two are American.

PHORONIS Wright. With the characters of the subphylum: 11
species.

Fig. 442 — Phoro-
nis architecta —
young individual
with about 30 ten-
tacles (Cowles). 1,
epistome ; 2, lopho-
phore ; 3, digestive
tract.

* See "Phoronis architecta," by R. P. Cowles, Mem. Nat. Acad., Vol. 10, p. 76,
1905. "On Phoronis pacifica sp. nov.," by H. B. Torrey, Biol. Bull., Vol. 2, p. 283, 1901.

CHAETOGNATHA 271

P. architecta Andrews (Fig. 442). Tubes straight and about 13 cm.
long and 1 mm. wide; anterior portion of body flesh color, posterior
portion reddish or yellowish; tentacles about 100 in number; lophophore
not spirally coiled at the ends: North Carolina, in sand flats near the
low-water mark, the tubes being isolated and covered with sand grains;
often common.

P. pacifica Torrey. Length of tube 9 cm.; diameter 2 mm.; each
spiral of lophophore with ll/2 to 2 turns; tentacles 170 to 200 in number;
tube straight, cylindrical, incrusted with sand: Puget Sound; Humboldt
Bay, California; in sand and mud flats.

SUBPHYLUM 7. CILETOGNATHA.*

Elongate, transparent worms of small size which live exclusively in
the sea, preying on other small organisms. The body is long and slender
and unciliated, and is provided with two or three pairs of horizontal fins.
Surrounding the mouth at the front end of the body are long, paired,
prehensile bristles or hooks and one or two rows of small teeth (Fig.
443, B). A large body cavity is present, which is lined with a peritoneum
and is divided by transverse septa into three compartments. The anus is
at the hinder end of the body and between it and the mouth lies the
straight digestive tract: longitudinal mesenteries join the intestine with
the dorsal and ventral body walls. The nervous system is subepithelial ;
a Iarg6 cerebral ganglion forms the brain and is connected with a large
ventral trunk ganglion in the middle of the body by commissures. The
brain sends off nerves to the two eyes and the unpaired olfactory organ
behind them. No special respiratory, excretory, or circulatory organs are
present. The animals are hermaphroditic, the sex cells arising from the
peritoneum. The two ovaries are in the middle division of the body, the
oviducts opening near them: the testes are in the hinder division of the
body; the spermatozoa escape to the outside through a pair of prominent
seminal vesicles just in front of the tail fins. In the development the
mesoderm is formed by the growth of paired pouches from the archenteric
walls, the fused cavities of the pouches becoming the ccelom, a process
characteristic of many annelids and also of the Chordata.

The Chcetognatha are found in all seas, from the surface to the
greatest depths, being often present in immense numbers. Six genera and
about 30 species are known.

* See "The Known Chaetognatha of American Waters," by P. S. Conant, Johns
Hopk. Univ. Cir., Vol. 15, p. 82, 1896. "Cbaetognathi," by R. von Ritter-Zahony, Das
Tierreich, 1911. "Classification, etc., of the Chaetognatha," etc., by E. A. Michael,
Univ. of Cal, Pub., Vol. 8, p. 21, 1911.

272

CH^TOGNATHA

Key to the American genera of Chcetognatha:

ox Two pairs of fins besides the caudal fin 1. SAGITTA

a2 One pair of fins besides the caudal fin.

&! Fins near the middle; body slender, with 1 row of teeth 2. EUKROHNIA

&2 Fins near the tail ; body broad, with 2 rows of teeth 3. PTEROSAGITTA

1. SAGITTA Quoy and Gaimard. Slender worms with 2
pairs of lateral fins : about 25 species.

S. elegans Verrill (Fig. 443). Length up to 3 mm.; 9 to
12 oral hooks; anterior teeth 4 to 8; posterior teeth 6 to 9:
North Atlantic.

S. hexaptera D'Orbigny. Length 6 mm.; oral hooks 5
to 10; anterior teeth 3 to 4; posterior
teeth 3 to 5: Martha's Vineyard; cos-
mopolitan.

2. EUKROHNIA Ritter-Zahony. A
single lateral fin on each side near mid-
dle of body; body slender: 3 species.

E. hamata (Mobius). Length 4
mm.; oral hooks 8
to 10; 15 to 28
teeth in a single
row ; ovary reddish :
cosmopolitan; Mar-
tha's Vineyard.

3. PTEROSAGITTA Costa. Body broad; a single
pair of lateral fins near the tail; an expansion of
the integument extending along the side of the body
in front of each lateral fin to the head : 1 species.

P. draco (Krohn) (Fig. 444). Length 10 mm.;
oral hooks 4 to 10; anterior teeth 6 to 9; posterior
teeth 12 to 18; forward of the middle of the body
on each side is a bundle of long setae : cosmopolitan.

Fig. 443 — Sagitta elegans (Zahony).
A, entire animal ; B, head. 1, pre-
hensile hooks ; 2, teeth ; 3, mouth ;
4, ventral ganglion ; 5, female gen-
ital organs ; 6, anus ; 7, female
genital pore ; 8, male genital pore.

Fig. 444
Pterosagitta draco

(Cambridge
Natural History).

SUBPHYLUM 8. SIPUNCULOIDEA.

Marine worms which, together with the Echiurida, are often included
in a class of the Annelida called the Gephyrea. This is a name given
them by Quatrefages (1847) to signify the belief that they bridge the
gulf between the Annelida and the Echinodermata, the earlier zoologists
having grouped them with the holothurians. The total lack of segmen-
tation, however, at any period of the life of most of the Sipunculoidea,
and the absence of metameric organs, have made it necessary to remove
them from the Annelida, although the fact that they pass through the

SIPUNCULIDA 273

trochophore stage indicates a close connection with the immediate ancestors
of that group.

The Sipunculoidea are more or less elongated worms, the largest of
which are 20 cm. or more in length, which live in the sand or mud, either
free or in tubes or snail shells. The body is cylindrical and very con-
tractile, unsegmented and not ciliated, and without metameric ap-
pendages, spines, or bristles; it is made up of two divisions, a usually
slender anterior portion called the introvert, which can be invaginated,
and the thicker hinder portion. The subphylum contains two classes.

Key to the classes of Sipunculoidea:

Cj Body elongate ; anus at base of introvert ; tentacles usually present.

1. SIPUNCULIDA
Oy Body robust ; anus at hinder end ; no tentacles 2. PBIAPULIDA

CLASS 1. SIPUNCULIDA.*

Elongated worms with short, hollow tentacles at the forward end
which are either distinct or more or less united and usually surround the
mouth, and with the anus in the dorsal surface near the base of the intro-
vert. The body wall consists of a cuticula, a single-layered hypodermis,
and the muscles. The hypodermis gives rise to large glands which lie
beneath it, in certain species enveloped in a gelatinous connective tissue
called the cutis, and open through the cuticula to the owter surface. The
muscles consist of an outer circular and an inner longitudinal layer and
between them delicate oblique muscles, which, however, are not present in
the introvert. The longitudinal muscles in certain species (Sipunculus)
are split up into regularly recurring bundles, which produce a lattice-like
effect (Fig. 446). The body cavity is voluminous and is bounded by a
ciliated peritoneal lining; it contains a corpusculated blood fluid. Two or
four retractor muscles extend back from the front end of the base of the
introvert, by means of which invagination is effected. The digestive system
consists of a narrow tube of about the same diameter throughout, which
extends from the mouth at the front end to near the hinder end of the
body, then turns on itself and extends forward to the anus. The two
limbs of the intestine are usually twisted spirally together, in certain
species around a single muscle strand called the spindle muscle. A blood
vascular system is present in form of an oesophageal ring canal, tentacular
canals which extend from the ring canal into the tentacles, and one or two
contractile ca3ca (hearts) which extend from the ring canal a short dis-
tance along the oesophagus. These organs contain a fluid which serves to
extend the tentacles, which are probably respiratory as well as sensory in

* See "Die Sipunculiden," by E. Selenka, in Reisen im Arch. d. Philipp, von C.
Semper, 1883. "The Sipunculids of the Eastern Coast of North America," by J. H,
Qerould, Prqc, TJ, S. Nat. Mus., Vol.. 44, p. 373, 1913.

274 SIPUNCULIDA

function. A pair of nephridia, called the brown tubes, opens to the out-
side near the anus. The nervous system consists of a cerebral ganglion
on the dorsal side of the resophagus, which is connected by a pair of
commissures with an unsegmented ventral nerve; this nerve passes to the
hinder end of the body, sending off numerous nerves which are not regu-
larly paired. A pair of simple eyes, pigmented or not, lies within the
brain. A ciliated canal extending from the surface to the brain and called
the cerebral tube, the walls of which are pigmented in certain species,
is present just back of the tentacles : tactile organs are also often present.
The sexes are separate, but alike in appearance. A pair of gonads de-
velops in the peritoneum upon the base of the retractor muscles which
discharge their products into the body cavity, whence they make their way
to the outside through the nephridia. The young animal passes through
ian active free-swimming stage. The metamorphosis is not accompanied
by any well-marked evidences of metamerism, and the adult worm is still
trochophore-like, indicating that the animals are very primitive forms
near the base of the annelid stem. The animals live in the sand and mud,
which they swallow in large quantities. They are found in almost all
parts of the world, mostly in shallow water. The class contains about 11
genera and over 100 species, 16 of which have been found on the east and
4 on the west coast of this country.

Key to the genera Sipunculida here described :

Oi Longitudinal muscles divided into bundles (except Phascolosoma gouldi).
&! Tentacular fold instead of tentacles; no papillae on trunk.. 1. SIPUNCULUS
62 Isolated tentacles present.

cx Tentacles encircle the mouth 2. SIPHONOSOMA

c2 Tentacles in a crescent dorsal to mouth 3. PHYSCOSOMA

a, Longitudinal muscles not split into bundles (with Phascolosoma gouldi).

&t Worms free-living with numerous tentacles 4. PHASCOLOSOMA

6a Worms inhabit tubes or shells 5. PHASCOLION

1. SIPTTNCITLTTS L. Mouth surrounded by a fluted tentacular fold,
without isolated tentacles, behind which is the cerebral tube; no hooks on
the introvert; longitudinal muscles in 17 to 41 distinct bundles, giving a
lattice-like effect; 4 retractor muscles; rectum with 1 or more caeca; 2
contractile hearts: 16 species, mostly of large size, in most seas.

S. nudus* L. (Fig. 445). Body up to 21 cm. long; the anterior
sixth covered with papillae; 13 longitudinal muscles: Beaufort, North
Carolina; Key West; Europe.

2. SIPHONOSOMA Spengel. Similar to Sipunculus but with integu-
mental blind sacs and a statocyst near the tentacles ; cerebral tube a shallow
pit: several species.

* See "On Some Points on the Anatomy and Histology of Sipunculus nudus L.,"
by H. B. Ward, Bull. Mus. Comp. Zool., Vol. 21, p. 143, 1891,

SIPUNCULIDA

275

Fig. 445 — Sipunculus
nudus — anterior end of
body with the introvert
extended (Ward).

S. cumanense ( Kef er stein). Longitudinal muscles 21; body cavity
divided by septa into regular subdivisions as in an annelid; oral tentacles
present: North Carolina; Florida; Philippines.

3. PHYSCOSOMA Selenka. Body covered with
papillae; usually 4 retractor muscles; introvert
with hooks arranged in rings; tentacles numer-
ous, not surrounding the mouth but lying above it,
forming a horseshoe; longitudinal muscles as in
Sipunculus; eye spots present: about 27 species,
mostly tropical.

P. agassizi Keferstein. Body up to 4 cm.
long and 10 mm. thick; introvert as long as
body; about 20 rows of broad hooks just back
of tentacles, of which there are 20; 25 longi-
tudinal muscles: Pacific coast, Vancouver to
Panama.

4. PHASCOLOSOMA F. S. Leuckart. Longitu-

dinal muscles usually not split up into bundles but
forming a continuous sheath; mouth surrounded by
one or more concentric circles of finger-shaped ten-
tacles; 2 or 4 retractor muscles in the introvert:
over 25 species, cosmopolitan, some species living
in the shells of snails.

P. gouldi* (Pourtales) (Fig. 446). Body with
longitudinal muscles not forming a continuous sheath
but split up into about 30 anastomosing bundles;
length 18 cm., the anterior quarter of which is pro-
boscis; skin smooth; tentacles very numerous, in sev-
eral rows; a pair of pigmented ocular tubes open
into the cerebral organ : Long Island Sound to Massa-
chusetts Bay.

P. eremita (Sars). Body with transverse ridges,
2 to 5 cm. long and 5 to 12 mm. thick; introvert
nearly as long as body, without hooks; 2 retractor
muscles; no spindle muscle; 20 to 40 tentacles:
Massachusetts coast northwards, in 40 to 1,000 fath-
oms; Arctic Ocean.

5. PHASCOLION Theel. Small forms living in
tubes or in small shells; tentacles numerous, form-

* See "Notes in the Anatomy of the Sipunculus gouldii Pourtales," by E. A.
Andrews, Stud. Biol. Lab. Johns Hopkins Univ., Vol. 4, p. 389, 1890. "The Develop-
ment of Phascolosoma," by J. H. Gerould, Zool, Jahrb. Abt f. Anat., etc., Vol. 23,
p. 77, 1906.

Fig. 446— Dissec-
tion of Phascolosoma
gouldi (Kingsley). 1,
mouth ; 2, anterior
retractor muscles ; 3,
intestine ; 4, neph-
ridium ; 5, posterior
retractors ; 6, gonad ;
7, nerve chord ; 8,
anus.

276 PRIAPULIDA

ing a single circle around the mouth; alimentary canal not spiral or

incompletely so; no spindle muscle; 2 retractors; but 1 brown tube: 15

to 20 species.

P. strombi (Montagu) (Fig. 447). Body 30 mm. long, with papillae;

a band of minute hooks back of tentacles, and large, dark-brown, cres-
centic or triangular hooks pointing forwards on the
hinder part: common in 2 to 1,000 fathoms from the
West Indies to the Arctic Ocean; Mediterranean; the
worm lives in a snail shell, closing the aperture by means
of sand cemented into a firm mass, leaving a hole through
which the introvert is thrust out, and moves about car-
rying the shell with it; common, there being many

Phascoiion varieties, some of which form a thick short tube of mud

strombi
(Gerould). and sand.

CLASS 2. PEIAPULIDA.

Body without tentacles; anus at the hinder end; introvert plump
and covered with rows of small spines; trunk striated transversely and
in most species bearing 1 or 2 large caudal appendages with respiratory
papillae; alimentary canal in most cases straight and wide; pharynx
muscular, provided with numerous teeth; main nervous system sub-
epithelial, consisting of a ring around the mouth and a ventral cord
without definite ganglia; no special sense organs, blood- vascular system,
or nephridia in the adult, but in the young worm nephridia are present
which open intd the genital ducts ; sexes distinct ; gonads paired ; genital
ducts open to the outside near the anus: 2 genera and 6 species, which
are found in shallow water in the colder seas, where they burrow in the
sand and mud.

PRIAPULUS Lamarck. Caudal appendages, covered with hollow
papillae present; introvert thicker than the trunk, about a quarter as
long as it and with spines in longitudinal rows : 5 species.

P. caudatus Lam. Length 2 to 18 cm., color yellow or brown:
Arctic seas.

PHYLUM IV.
ANNELIDA.* (THE ANNELID WORMS.)

Elongated, segmented worms in which a distinct head, a coelom, and
a digestive tube are present, and the paired appendages, where present,
are not segmented.

External Structure.— The segmentation, which is the most character-
istic feature of annelids, is approximately equivalent (Fig. 461, A).
This is the most pronounced in the Ch&topoda, in which it affects both the
inner and the outer structure, the segments or somites being separated
from one another by muscular partitions called dissepiments; in the
Hirudinea and the Myzostomida the internal structure is also completely
segmented but the rings which appear ou the outer surface may not mark
the somites; in the Echiurida the larval worm alone is segmented.

A head is more or less distinctly marked in most annelids and contains
the mouth, the brain, and also often tentacles, cirri and palps, which
may have a tactile and often a respiratory function; eyes are also often
present. The head is typically composed of two divisions (Fig. 459), the
prostomium and the peristomium or metastomium. The first of these
divisions is a distinct projection which forms the anterior end of the
animal; it lies in front of the mouth (Fig. 450, A) and contains the brain
and the eyes, tentacles, and palps, if these are present. The second con-
tains the mouth, which is ventral in position, and often cirri, and is con-
tinuous with the segmented trunk, in many annelids appearing as a
part of it.

Paired, segmental appendages, which in the annelids 'are muscular
projections of the body wall and are called parapodia, are present in the
Polych&ta and the Myzostomida, and all annelids except the Hirudinea,
most Archiannelida, and the Discodrilidae, possess paired, segmental groups
of bristles, which are called setae and assist in locomotion. The parapodia
are locomotory, respiratory, and tactile in function. The Hirudinea and
a few other groups possess suckers, which assist in locomotion.

The outer surface of the body of annelids is a cuticula and is usually
not ciliated in the adult worm.

* See "Invertebrate Animals of Vineyard Sound," by A. E. Verrill, Rep. U. S.
Com. Fish, for 1871-72. "Preliminary Account of the Marine Annelids of the Pacific
Coast," etc., by H. P. Johnson, Proc. Cal. Acad. Sci. (3), Vol. 1, 1897. "A Biological
Survey of the Waters of Woods Hole and Vicinity," by F. B. Sumner, et al., Bull. Bur.
Fish., Vol. 31, 1913.

277

278 ANNELIDA

Internal Structure.— The body wall consists of the cuticula, which
forms the outer covering, the hypodermis, a single layer of cells which
secretes the cuticula, and two layers of muscle fibers, an outer circular
and an inner longitudinal layer. In the Hirudinea and Myzostomida the
body cavity is filled more or less completely with a vacuolated connective
tissue and muscle fibers, similar to the parenchyma of the Plathelminthes.
In other annelids a spacious body cavity is present, which is usually
divided by the dissepiments into as many separate spaces as there are
somites.

The mouth leads into the pharynx (Fig. 487,5), which in most anne-
lids can be thrust out through the mouth to form a proboscis, and
is the means by which the 'animal takes its food. An oasophagus is
usually distinctly marked and is followed by the intestine, which in most
cases is straight and passes to the anus at the hinder end of the body; in
many annelids a pair of lateral intestinal pouches is present in each
somite and a dorsal and a ventral longitudinal mesentery joins the intestine
with the body wall.

A well-developed system of blood tubes (Fig. 487, 7) is present in all
except the lowest annelids, which often carry red blood, the most impor-
tant of which are a dorsal longitudinal tube just above the intestine, a
ventral tube just beneath it, and transverse tubes placing these in com-
munication with each other. The body cavity has also a circulatory fluid
of its own which in many annelids is in open connection with the blood
tubes.

The excretory system (Fig. 479, 6) consists typically of a pair of
coiled tubes called kidney tubules or nephridia in each somite. Each neph-
ridium opens into the body cavity by the ciliated nephrostome at one end
and to the outside through a pore in the body wall at the other. Respira-
tion is carried on through the entire outer surface of the body. In the
Polych&ta, however, special respiratory organs are present in the form of
projections of the parapodia or the appendages of the head.

The nervous system (Fig. 479) consists of paired, segmental, ven-
trally situated ganglia and a pair of longitudinal nerves joining them.
The anterior ganglionic mass constitutes the brain ; it is dorsal in position,
being situated above the pharynx in the prostomium. In their most
primitive condition these two longitudinal nerves are separated from each
other, but in most annelids they lie close together, forming a single strand.
Special sense organs exist in a variety of forms. Tactile organs in the
form of the paired appendages of the head and trunk characterize the
polychaets and the Myzostomida; in the oligochaets and leeches the entire
forward portion of the body is highly sensitive. Eyes are present in
polychaets and leeches, and a few of the former also possess lithocysts.

GENERAL DESCRIPTION 279

In the unisexual annelids (most polychasts) the reproductive organs
are not well marked except during the period of breeding, when they
appear as specialized portions of the peritoneum. The hermaphroditic
annelids on the other hand have a complicated system of reproductive
organs (Fig. 479). The unisexual forms are mostly born in the form of
the trochophore larva, which goes through a complicated metamorphosis
before reaching the condition of the adult : in the hermaphroditic annelids,
the development is usually direct, the young worm when born having the
form of the parent. The body of the typical, primitive annelid may be
divided into two portions, the prosoma, or the primitive head, and the
metasoma, or the primitive segmented trunk. The trochophore larva,
which in most cases is supposed to represent the prosoma alone, is a
simple unsegmented animal, the metasoma not yet having made its appear-
ance. The metasoma soon begins to grow, however, at the posterior end
of the prosoma, the segments or somites developing one after the other as
the worm increases in length, until in some cases a hundred and fifty or
more may be present in the adult worm. In the higher annelids the
prosoma annexes one or more of the anterior somites of the trunk and
forms thus a head of increased size and complexity in which we can dis-
tinguish the two divisions already mentioned, the prostomium and the
peristomium.

In the hermaphroditic annelids, which have a direct development,
these processes go on in the egg and the young worm is born with its
definitive form, although usually not with the full number of somites.
Many annelids reproduce also asexually by transverse divisions or by
serial or even lateral budding.

Distributions and Habits. — All annelids live in the water or in moist
places on the land or in the earth, the majority being marine. Most of
them are predaceous animals, although the oligochaets live chiefly on veg-
etable substances. The leeches are either predaceous or parasitic and the
Myzostomida are exclusively parasitic.

History.— It was Cuvier who, in 1798, first called attention to the
fundamental difference in structure between the higher and the lower
worms, and Lamarck who gave the former the name Annelides. Savigny
(1820) subdivided the group into the Annelides nereideae, serpuleae, lum-
bricineae, and hirudineae, and may be considered the founder of the
modern classification. Milne-Edwards (1834) introduced the subdivisions
Annelides errantes, tubicoles, and terricoles, which for sixty years or more
had a place in the system, and Grube (1851) the subdivisions Polychceta
and Oligoch&ta, which are still in general use. In more recent times
Ehlers has been perhaps the most active in the development of the system.

The phylum contains about 4,500 species grouped in 4 classes.

280 ANNELIDA

Key to the classes of Annelida:

Ox No suckers or sucker-like organs present (except in the Discodrilidae) ;

segmentation usually distinct externally.
Z>! No setae (except in Chcetogordius) or parapodia present. 1. ABCHIANNELIDA

62 Setae present 2. CH^ETOPODA

O2 Suckers or sucker-like organs present.
Z>! Body ringed externally with a terminal sucker at each end ; leeches.

3. HIRUDINEA
&, Body flat and oval in shape with 5 pairs of parapodia and 4 pairs of

sucker-like organs ; parasites on echinoderms 4. MYZOSTOMIDA

CLASS 1. ARCHIANNELIDA.

Primitive, marine worms of small size, which are probably near the
base of the line of the Annelida, having many characters which ally them
to larval polycha3ts: 2 isolated, genetically unrelated families,

Key to the families of Archiannelida :

d Body with 5 or 6 segments, marked by ciliated bands 1. DINOPHILIDAE

at Body with numerous segments 2. POLYGOBDIIDAE

FAMILY 1. DINOPHILIDAE.*

Minute, marine worms living among seaweed; body short, thick, and
cylindrical, and made up of a head or prostomium, a trunk consisting of
5 or 6 segments, and a telson or tail; head with a pair of
eyes, 2 bands of cilia and tactile bristles, no tentacles
being present; each segment with 1 or 2 bands of .cilia;
ventral surface also ciliated; sexes separate and develop-
ment simple, the worm becoming adult at a stage resem-
bling a polychaBtous larva: 1 genus and about 9 species, 3
American.

DINOPHILTTS Schmidt. With the characters of the
family.

D. pygmaeus Verrill. Length .7 mm. ; width .16 mm. ;
trunk segments 5; color whitish: Woods Hole, on piles.
Fig. 448 JD. gardineri A. Moore. Color orange red ; trunk seg-

Dcoil&ini8 ments 6; body ciliated in addition to the ciliated bands:

Woods Hole, in brackish pools.

D. conklini Nelson (Fig. 448). Length .5 to 1 mm.; colorless; trunk
segments 6: New Jersey coast.

FAMILY 2. POLYGORDIIDAE.

Small, marine annelids in which the segmentation is completely
equivalent and often indistinctly marked externally or not at all, and

* See "Dinophilidae of New England," by A. E. Verrill, Trans. Conn. Acad., Vol.
8, p. 457. "The Morphology of Dinophilus conklini n. sp.," by J. A. Nelson, Proc.
Acad. Nat. Sci., Phila., Vol. 59, p. 82, 1907.

ARCHIANNELIDA

281

Fig. 449

Larva of

Pohigordius

appendiculatua

(Cowles).

which have no parapodia and usually no segmental setae; head com-
posed of prostomium and metastomium, the former lying in front of
the mouth and bearing a pair of tentacles, the latter larger than the
prostomium and without appendages; body cavity,
digestive, excretory, and vascular systems typically
annelidan in character; nervous system subjacent to
the hypodermis and without distinct ganglia; animals
unisexual, the genital products developing from special-
ized regions of the peritoneum during the breeding
season; young born as trochophore larvae: 2 or 3
genera ; the larvae are common in the plankton at many
places along the Atlantic coast, but with the exception
of Ch&togordius no adult worms have been found.

1. POLYGORDIUS Schneider. Body filiform; segmentation indistinct
at the forward end but more distinct at
the hinder; tentacles short; anal segment
enlarged: about 6 species.

P. appendiculatus* Fraipont (Fig.
449). Length 20 mm.; body salmon color;
2 long anal appendages present: Atlantic
coast (only larval forms heretofore
found) ; Mediterranean.

2. CH^TOGORDIUSJ Moore. Segmenta-
tion as in Polygordius; hindermost 10 or
12 segments setigerous; no anal enlarge-
ment: 1 species.

C. canaliculatus Moore (Fig. 450). Length 30 mm.: among marine
oligochaets on Cape Cod.

CLASS 2. CILETOPODA4

Segmentation distinct, except in the Echiurida, both internally and
externally; setae segmentally arranged in groups on the parapodia, where
these are present, or sunk in pits on the integument: 3 orders.

* See "On the Rearing of the Larvae of Polygordius appendiculatus and the
Occurrence of the Adult on the Atlantic Coast of America," by R. P. Cowles, Biol.
Bull., Vol. 4, p. 125, 1903.

t See "A New Generic Type of Polygordius," by J. P. Moore, Am. Nat., Vol. 38,
p. 519, 1904.

% See "Annelida Chaetopoda of New Jersey," by H. E. Webster, Thirty-second Rep.
N. Y. St. Mus. Nat. Hist., p. 128, 1879. "New England Annelids," by A. E. Verrill,
Trans. Conn. Acad., Vol. 4, p. 285, 1881. "The Annelida Chsetopoda from Province-
town," etc., by H. E. Webster and J. E. Benedict, Rep. Com. Fish, for 1881, p. 699,

1884. "The Annelida Chaetopoda from Eastport, Maine," by same, same jour, for

1885, p. 707, 1887. "The Annelida Chaetopoda of Beaufort, N. C.," by E. A. Andrews,
Proc. U. S. Nat. Mus., Vol. 14, p. 277, 1891. "Polychseta of the Puget Sound Region,"
by H. P. Johnson, Proc. Bost. Soc. Nat. Hist., Vol. 29, p. 381, 1902.

Fig. 450 — Chcetogordius cana-
liculatus (original drawings by
J. P. Moore). A, anterior end;
B, posterior end.

282

ANNELIDA

Fig. 451 — 'Diagram of parapodia
(Cambridge Natural History). A,
Nephthys : B, Amphinome ; C, Gly-
cera; D, Syllis; E, Leodice ; P, Phyl-
lodoce. 1, notopodium ; 2, neuropo-
dium ; 3, cirrus.

Key to the orders of Chcetopoda:

<*! Segmentation distinct.
bi Parapodia with complex groups of setae ; usually cephalic appendages

present ; mostly marine 1. POLYCH^STA

ba No parapodia or cephalic appendages present; mostly fresh-water or

terrestrial 2. OLIGOCH^TA

o, Segmentation indistinct or wanting in adult; marine 3. ECHIUBIDA

ORDER 1. POLYCH-STA.

Mostly marine annelids, either free-
swimming or sedentary, which are pro-
vided with parapodia. Two portions
may usually be distinguished in the
parapodium (Fig. 451), the dorsal no-
topodium and the ventral neuropodium,
both of which may contain setae; two
cirri, a dorsal and a ventral, extend
from it. In the sedentary polychaets
the parapodia are much reduced in
size on either the whole or a part of
the body and in a few they 'are entirely
wanting.
The polychaBts have a distinct head which is usually provided

with special sense organs (Fig. 452). The prostomium may bear ten-
tacles, which may number from one

to ten and are dorsal in position,

and two palps which are ventral

and in certain forms are broken

up into long respiratory filaments.

Elongated peristomial cirri may

also be present. Eyes are often

present on the prostomium and

lithocysts are found in a few forms

(Arenicola). The mouth is in the

peristomium and is often provided

with a proboscis. Polychaets are

often highly colored; bright red,

green, blue, and yellow tints char-
acterize many of them and make

them very beautiful animals.

Polychsets are usually born as

trochophore larvae and pass through a metamorphosis before reaching

the adult stage. Many reproduce asexually by serial or even lateral

Fig. 452 — Diagram of the beads of
various polychaets (Cambridge Natural
History). A, polynoid ; B, syllid ; C,
Nephthys; D, Leodice; E, Phyllodoce;
F, Trophonia. 1, prostomium ; 2, peri-
stomium ; 3, tentacles ; 4, palps ; 5,
peristomial cirri.

POLYCH^TA 283

budding. In many the anterior part of the body is sexless and is called
the atoke, while the hinder part is sexual and is called the epitoke, these
two portions being different in appearance; in some the epitokes break
off from the atokes and swim about independently, while the atokes bud off
new epitokes. The palolo worm of the Samoan and Fiji Islands is the
epitoke of Leodice viridis, which comes to the surface in great numbers at
the full of the October moon to breed, and which are caught by the natives
for food. The palolo worm of the Atlantic is L. fucata. In Syllis the
epitoke forms a new head; in Autolytus this happens before separation.

In certain species of Nereis heterogony is present, a small pelagic
form alternating with a large one which lives at the bottom.

Distribution and Habits.— A very few polychaets live in fresh water
(Manayunkia in the Schuylkill, a Nereis in California, and several others) ;
the remainder, which are marine, are almost all bottom animals which
burrow in the sand or in rocks or live in tubes they have built for
themselves of lime or other material. They are found at all depths and
are usually numerous in all parts of the world. The free-swimming poly-
cha3ts are predaceous animals, while the sedentary ones live on 'all kinds of
organic substances ; a few are parasitic, and a number commensalistic.

The order contains about 39 families and 2,500 species grouped in 7
suborders.

Key to the suborders of Polychceta:

&! Worms free-swimming or burrowing, a few tubicolous ; head distinct, with

tentacles and palps 1. NEKEIDIFOEMIA

a2 Worms tubicolous or burrowing ; head not so distinct and not provided

with both tentacles and palps ; sometimes with neither.
6X Peristomium does not project forwards in form of a collar.
CL Head with gill filaments (except in Cirratulidae) . . . .3. TEBBEBELLIFOBMIA
C2 Head without gill filaments.

di One pair of long peTistomial cirri present. 2. SPIONIFOBMIA

d 2 One pair of retractile tentacle-like organs on head . . 4. CAPITELLIFOBMIA

d3 Head with no appendages (except in Chlorhcemidae) 5. SCOLECIFOBMIA

Z>2 Peristomium projects forward in form of a collar.

Cj Peristomial collar not setigerous 6. SABELLIFOBMIA

c2 Peristomial collar setigerous 7. HEBMELLIFOBMIA

SUBORDER 1. NEREIDIFORMIA.*

Well-developed tentacles and palps present; peristomial cirri almost
invariably present; parapodia well developed, with internal skeletal rods
called acicula and ventral and dorsal cirri; proboscis present, often
with prehensile hooks; worms predacious, a few forming tubes: about
13 families.

* See "Die Borstenwurmer," by E. Ehlers, 1864.

284

ANNELIDA

Key to the families of Nereidiformia here described:
Oj Back partially or totally covered with broad, overlapping scales.
az Back without these scales. 1* ^PHBODITIDAE
&! Dorsal cirri broad and leaf-like, overlapping one another, but not cover-
ing the back 2. PHYLLODOCIDAE

62 Cirri not broad and leaf-like.

Cx Dorsal cirri usually long and slender; asexual budding usual. .3. SYLLIDAE
c2 Dorsal cirri not very long ; asexual reproduction unusual,
dj Prostomium not annulated.
€1 No large teeth or jaws on proboscis.

/! Proboscis simple; parapodia usually uniramous 4. HESIONIDAE

/2 Proboscis divided into lobes ; prostomium small and acute. .9. AKICIIDAE
et Two or more large teeth or jaws usually on proboscis.
/! But 1 pair of jaws ; 1 pair of tentacles, 1 pair palps and 4 pairs

peristomial cirri 5. NEREIDAE

/2 Two or more pairs of jaws.

Oi One pair of dorsal and 1 pair of ventral jaws 6. NEPHTHYDIDAE

ga Jaws form a complicated apparatus 7. LEODICIDAE

di Prostomium annulated ; tentacles inconspicuous ; proboscis very large.

8. GLYCEBIDAE

FAMILY 1. APHRODITIDAE. (FiG. 452, A.)

Worms with imbricated scales (elytra) on the back, mostly on alter-
nate segments, which may take the place of dorsal cirri; slender dorsal

cirri usually alternate with the scales; head
with usually 3 tentacles and 2 long palps:
numerous genera and species.

Key to the genera of Aphroditidae described :

ax Body with felt-like bristles on sides and back

concealing the elytra 1. APHRODITA

a2 Body without this felt.
&! Body with but few pairs of elytra.
cx Prostomium prolonged into the base of the
lateral tentacles ; 12 pairs of elytra.

2. LEPIDONOTUS

c2 Prostomium produced forward into a pair
of pointed tips, quite free from the base

of the tentacles 3. HABMOTHOE

&2 Body with numerous pairs of elytra.

Ci Over 40 pairs present 4. PHOLOE

c2 Over 100 pairs present 5. STHENELAIS

- i V'A ' •'*•••• ' if'/1 > -i

Fig. 453
Aphrodita hastata (Moore).

1. APHRODITA L. Body elliptical, with 15
pairs of elytra; entire back covered by the
long felt-like setae arising from the notopo-
dium; strong dorsal setae also present, projecting through the felt; 1
short- tentacle and 2 long palps on the head : about 15 species, 2 in the
Woods Hole region.

A. hastata Moore (Fig. 453). The Sea Mouse. Body short, wide,
and thick, the sides and back covered with the iridescent felt; dorsal

POLYCH^TA

285

Fig. 454

Lepidonotus

squamatus.

(Verrill).

setae curve over the back to the middle line where they end in hooks;
length 12 cm.; width 4 cm.: Vineyard Sound, in from 10 to 100
fathoms.

2. LEPIDONOTTTS Leach. Body broad, with nearly parallel sides,
and 12 pairs of elytra; head with 3 tentacles, 2 long palps, and 2 pairs
of peristomial cirri; eyes sessile: under stones near tide

lines; 2 New England species.

L. squamatus (L.) (Fig. 454). Elytra tuberculated ;
color dark brown; length about 3 cm.; width 8 mm.: very
common from New Jersey to Labrador; Europe.

L. sublevis Verrill. Elytra smooth ; color light brown
or gray, with spots; length about 3 cm.; width 7 mm.:
Virginia to Massachusetts; not so common as the above.

3. HARMOTHOE Kinberg. Body flattened and elon-
gate, with 15 pairs of elytra; head bilobed and with 3
tentacles, 2 long palps, 2 pairs of peristomial cirri and 4
eyes; segments completely or nearly covered by elytra:
2 New England species.

H. imbricata (L.). Color variable, grayish or brownish, sometimes
with a black dorsal stripe; 42 to 44 segments; 2 to 3 cm. long: Long
Island to Greenland; from low- water mark to 60 fathoms; Europe;
North Pacific.

H. aculeata Andrews (Fig. 455). Surface covered with spines; 34

segments; length up to 2 cm.: the com-
monest scale annelid at Beaufort, N. C.;
under stones, etc., in shallow water.

4. PHOLOE Johnston. Body with
less than 70 segments and with numer-
ous pairs of elytra which alternate with
the dorsal cirri anteriorly but occur on
every segment posteriorly; 2 pairs eyes;
2 short peristomial cirri; 1 tentacle:
several species, 1 in New England.

P. minuta (Fabricius) (Fig. 456).
Number of segments in adult about 68;
number of pairs of elytra 44; length

2 cm.: Cape Cod, and northwards; in shallow water; Europe; North
Pacific.

5. STHENELAIS Kinberg. Elongated worms with numerous seg-
ments (over 100) and but 1 tentacle; 2 pairs eyes; elytra very numer-
ous, alternating with dorsal cirri anteriorly but on every segment pos-
teriorly: many species, 2 in the Woods Hole region.

Fig. 455

Fig. 456

Fig. 455 — Harmothoe aculeata —
head with extended proboscis (An-
drews). 1, proboscis ; 2, palp ; 3,
tentacles ; 4, peristomial cirri ; 5,
prpstomium. Fig. 456 — Pholoe
minuta (Leunis).

286 ANNELIDA

S. leidyi Quatrefages (S. picta Verrill). More than 150 pairs of
elytra present; color grayish with a mid-dorsal stripe; head brown with
a central red spot and a white spot on each side; length 15 cm.; width
4 mm.: North Carolina to Massachusetts Bay, in shallow water.

FAMILY 2. PHYLLODOCIDAE. (FiG. 452, E.)

Elongated, active polychsets with broad, leaf-like dorsal and ventral
cirri which do not cover the back; prostomium with 4 or 5 short ten-
tacles and 2 or 4 eyes; peristomium with usually 4 long cirri on each
side; proboscis with longitudinal rows of prominent papillae: about a
dozen genera with numerous species.

Key to the genera of Phyllodocidae here described :

«! Four pairs of peristomial cirri present.

61 Four tentacles 1. PHYLLODOCE

62 Five tentacles 2. EULALIA

c2 Two pairs of peristomial cirri 3. ETEONE

1. PHYLLODOCE Savigny. Body long, slender, and flattened, with 4
tentacles on the prostomium, and often a pair of rudimentary parapodia
on the peristomium together with the cirri: about 60 species, 7 in New
England.

P. gronlandica Oersted. Color green or yellowish with irregular
brown markings ; usual length 10 to 15 cm. : New Jersey to Greenland,
from low-water mark to 50 fathoms.

P. catenula Verrill. Color pale green with longitudinal rows of
brown spots on the back; prostomium longer than broad, with a pair of
large brown eyes; tentacles short; peristomial cirri very long; length
up to 7 cm.; width 1.5 mm.: Rhode Island to Bay of Fundy and north-
wards, from low-water mark to 50 fathoms; common.

2. ETTLALIA Oersted. Body slender and flattened, with 5 tentacles
on the prostomium and 4 pairs of peristomial cirri: 7 species in New
England.

E. pistacia Verrill. Color bright yellowish-green; body slender;
tentacles short; peristomial cirri long; length 4 cm.; width 1.5 mm.:
Long Island Sound to Maine, in 4 to 12 fathoms, among hydroids, etc.

3. ETEONE Oersted. Body slender, flattened with 4 tentacles and
2 pairs of cirri on somite 2 which is fused with the peristomium: 4
species in New England.

E. alba Webster. Color white; length 40 mm.: on mussel beds;
New Jersey to Cape Cod.

FAMILY 3. SYLLIDAE. ( FIG. 452, B.)

Elongated worms, mostly under an inch in length, with usually very
long slender dorsal cirri, which may be flattened; prostomium with 3

POLTCH^ETA

287

tentacles, 2 palps, and 4 eyes ; peristomium with 2 cirri on each side ;
reproduction normally by asexual budding: numerous species; abundant
in clean, shallow water among hydroids, mussels, and tunicates.
Key to the genera of Syllidae here described:

at Palps prominent; ventral cirri present; tentacles and cirri segmented.

1. SYLLIS
o2 Palps rudimentary ; ventral cirri absent ; tentacles and cirri filiform.

2. AUTOLYTUS

1. SYLLIS Savigny. Tentacles and cirri segmented, the latter often
terminally dilated; palps large; new individuals formed by terminal,
and in case of Syllis ramosa, lateral budding: numerous

species, 2 in the Woods Hole region.

S. pallida Verrill. Body slender, tapering at both
ends, 15 to 25 mm. long; color white:
Long Island Sound to Bay of Fundy; in
mud, sand, and on shells, from low-water
mark to 30 fathoms.

2. AUTOLYTUS* Grube. Tentacles and
cirri not segmented; palps rudimentary
or absent; ventral cirri wanting; the
young individual acquires a head before
separating from the parent, and a num-
ber may be present in a row; males and
females differ in appearance: numerous
species, 6 in the Woods Hole region.

A. cornutus A. Agassiz. Length 15
mm. ; color pinkish ; full-grown male hav-
ing 30 segments, female 40 to 50 seg-
ments: New Jersey to Bay of Fundy,
from low- water mark to 15 fathoms;
common.

A. varians Verrill (Fig. 457) . Length
15 mm.; intestine with bright-red spots which can be seen through the
body wall: North Carolina to Maine, often among hydroids.

Fig. 457

Fig. 458

Fig. 457 — Autolytus varians
(Mensch). 1, tentacles; 2, peri-
stomial cirri ; 3, budding individ-
uals. Fig. 458 — Podarlce obscura
(Verrill).

FAMILY 4. HESIONIDAE.

Body rather short and often cylindrical; parapodia usually unira-
mous and with long, jointed dorsal setae; 4 eyes, 2 or 3 tentacles, and
2 palps on the prostomium; peristomium with long cirri: species not
numerous.

* See "Autolytus," by P. C. Mensch, Jour, Morph., Vol. 16, p. 269, 1900,

288

ANNELIDA

PODARKE Ehlers. Six pairs of long cirri on the peristomium and
first two somites: several species.

P. obscura Verrill (Fig. 458). Color variable, usually brown or
blackish, sometimes with transverse bands; length up to 4 cm.; width,
including setae, 3 mm.: Gulf of Mexico to Cape Cod; on eel grass and
under stones; abundant.

FAMILY 5. NEEEIDAE. (Fro. 459.)

Fig. 459 — Head of a
nereid. 1, prostomium ;
2, tentacles ; 3, palp ; 4,
peristomial cirri ; 5,
peristomium.

Elongated polychaets with 2 small tentacles, 2 palps, 4 eyes on
the prostomium, and 4 pairs of peristomial cirri; proboscis with 2
large jaws: parapodia well developed: several
genera.

NEREIS L. Clam worms. Body elongate and
flattened; in some species during the sexual
period the hinder part (epitoke) of the animal
with the sexual products differs from the forward
part (atoke) in appearance and the animal is
called a heteronereis : numerous species, 7 in the
Woods Hole region.

N. virens Sars. Large worms, flesh-colored, with a
greenish sheen; jaws black; dorsal division of notopo-
dium foliaceous; length up to 30 cm. or more; width
1 cm. : common from Long Island Sound to Labrador,
buried in the sand near the low- water mark; breeding
season spring; Europe.

N. limbata Ehlers (Fig. 460). Color brownish;
jaws light amber-colored; dorsal division of notopodium
foliaceous ; length up to 15 cm. : Maine to South
Carolina; in the sand from high-water mark to 5 fath-
oms; abundant south of Cape Cod.

N. pelagica L. Color reddish-brown; body widest
in the middle; dorsal division of notopodium conical;
length up to 20 cm.; width 8 mm.: Virginia to Green-
land; on hard bottoms from low- water mark to 100
fathoms; Europe; North Pacific.

N. limnicola* Johnston. Color reddish-brown; length 47 mm.;
width 3 mm.; eyes large and conspicuous: in fine sand in Lake Merced
(fresh water) near San Francisco.

* See "Fresh-water Nereids from the Pacific Coast and Hawaii," etc., by H, P,
Johnston, Mark Ann. Vol., p. 205, 1903.

Fig. 460

Nereis limbata —

anterior end

with extended

proboscis

(Verrill).

1. proboscis

2, jaws.

POLYCH^TA 289

FAMILY 6. NEPHTHYDIDAE.

Elongated polychaets with flattened dorsal and ventral surfaces,
giving a quadrangular cross section; prostomium with 4 small tentacles,
the ventral pair being modified palps ; peristomium with parapodia bear-
ing setae and a pair of short cirri; proboscis very large with long fleshy
projections in front; the two lobes of the parapodia widely separate:
few genera and species.

NEPHTHYS Cuvier (Fig. 452, C). Characters as given above: nu-
merous species, 4 in the Woods Hole region.

N. incisa Malmgren (N. ingens Stimpson). Proboscis with large
dorsal and small ventral papillae; length 13 cm.; color white: Long
Island Sound to Bay of Fundy and northwards, from below low-water
mark to 60 fathoms, on muddy bottoms; Europe; common.

N. bucera Ehlers (N. picta Ehl.). Body slender with over 100 seg-
ments; setae very long, often exceeding in length the diameter of the
body; forward tentacles longer than half the width of head; length 20
cm. ; width 5 mm. : South ' Carolina to Massachusetts Bay, in shallow
water in sand, and among rocks.

FAMILY 7. LEODICIDAE.

Elongated polycheets with a complicated jaw apparatus in the pro-
boscis; the cirri of the anterior parapodia form branching gills in most
species; prostomium either with 3 to 5 tentacles and a pair of palps or
without cephalic appendages; usually a permanent parchment-like tube
formed: about 30 genera with several hundred species.

Key to the genera of Leodicidae here described :

ax Gills present.
&! Peristomium consisting of 1 segment and with cirri ; gills branched.

2. DIOPATBA
62 Peristomium consisting of 2 segments.

ct Gills branched 1. LEODICE

c2 Gills simple 3. MAEPHYSA

rt. Gills absent.
6X Head without appendages.

ct Eyes absent 4. LUMBRINEREIS

c2 Four eyes in a transverse row 5. ARABELLA

6, Head with appendages 6. STAURONEREIS

1. LEODICE Savigny (Eunice Cuvier) (Fig. 452, D). Body elongate
with numerous segments; peristomium consists of 2 segments with 1 pair
of cirri ; 5 tentacles and 2 large palps present ; gills begin usually on sixth
segment: species very numerous, 2 in the Woods Hole region, in rather
deep water. To this genus belong the largest known polvch^ts, the larg-
est species having a length of 1 m. and more.

290

ANNELIDA

L. fucata* Ehlers. Atlantic palolo worm (Fig. 461). Length up to
35 cm., the atokal portion being about two-thirds the whole; color
brownish or yellowish: West Indies and Gulf of Mexico; living in coral
rock and swarming within 3 days of the full of the July moon.

2. DIOPATRA Ehlers. Peristomium with

1 pair of cirri; 5 tentacles in a transverse
curved line and 2 small palps present; gills
beginning several segments back from the
head: many species, 1 in New England.

D. cuprea (Bosc) (Fig. 462). Large
worms up to 30 cm. long and 10 mm. wide
which live in parchment-like tubes extending

2 or 3 feet in the sand, the upper 2 or 3 inches
of the tube projecting into the water and
thickly covered with shells, etc.: common in
shallow water and between tide lines; from
South Carolina to Cape Cod.

3. MARPHYSA Quatrefages. Peristomium
consists of 2 segments, and is without cirri;
5 tentacles in a transverse row, 2 small palps

and 2 eyes present; gills begin about the 20th segment but are variable
in this respect: 1 species at Woods Hole.

M. leidyi Quatr. (M. sanguinea Leidy) (Fig. 463). Length 20 cm.;
color yellowish or brownish-red; tubes not so perfect as those of pre-
ceding worms: under stones and in the sand in shallow water; from
North Carolina to Vineyard Sound. I

4. LTTMBRINEREIS Blainville (Lum-
briconereis Ehlers). Head conical, without
appendages or eyes ; peristomium consist-
ing of 2 segments; dorsal cirri flat, and
parapodia small: many species, 5 at
Woods Hole.

L. tennis (Verrill). Body filiform
up to 30 cm. long, with the diameter of
a coarse thread, bright red in color: Vir-
ginia to Massachusetts; burrowing in
mud and under stones.

5. ARABELLA Grube. Similar to

Fig. 461 — Leodice fucata

(Mayer). A, entire worm;

B, head end. 1, tentacles ;

2, palp ; 3, peristomium ; 4,

peristomial cirri ; 5, gills.

Fig. 462

Fig. 463

Fig 462 — Diopatra cuprea — ven-
tral view of anterior end (Verrill).
1, tentacles ; 2, peristomial cirrus.
Fig. 463 — Marphysa leidyi — ante-
rior end (Verrill).

Lumbrinereis but with usually 4 eyes in a transverse row on the
prostomium: several species, 2 in the Woods Hole region.

* See "The Annual Breeding-Swarm of the Atlantic Palolo," by A. G. Mayer,
Carnegie Inst., Wash., Pub. 102, 1908.

POLTCH^TA

291

A

A. opalina (Verrill) (Fig. 464). Body cylindrical, largest in the
middle, reddish or yellowish in color, up to 40 cm. long, and 3 mm. wide :
North Carolina to Maine; burrowing in muddy sand; common; West
Indies.

6. STATJRONEREIS Verrill. Prostomium small and
quadrangular with 2 tentacles and 2 palps; gills not
present, the dorsal cirri being long and slender: several
species, 1 in the Woods Hole region.

S. pallidus Verr. Two pairs of eyes present; color
pale yellow ; length 5 cm. ; width .7 mm. : Virginia to Cape
Cod ; in the sand at low-water mark.

FAMILY 8. GLYCEEIDAE.

Fig. 464
Arabella
opalina —
anterior end
(Verrill).

Elongated cylindrical worms with usually small para-
podia, and an annulated prostomium which bears 4 small
tentacles and 2 rudimentary palps; proboscis very large and long, with
4 teeth; special retractile gills present either on the body wall or the
parapodia: about 5 genera; the worms live in cylindrical passages in the
sand, which they make with the proboscis.

Key to the genera of Glyceridae here described:

G! Parapodia of same structure throughout 1. GLYCEKA

a2 Parapodia with 1 lobe on anterior third of body and 2

lobes on posterior portions 2. GONIADA

1. GLYCERA Savigny. Parapodia of the same struc-
ture throughout: several species, 3 at Woods Hole.

G. dibranchiata Ehlers (Fig. 465). Length 20 cm.;
prostomium sharp and conical; both dorsal and ventral
gills large, simple, and flat: from North
Carolina to Bay of Fundy and north-
wards; in shallow water, burrowing
very rapidly in sand and mud; often
very common.

G. americana Leidy (Fig. 466).
Length 20 cm. ; width 4 mm. ; dorsal gills
branched; ventral gills absent: from
South Carolina to Cape Cod; in shallow
water; not so common as G. dibranchiata.

2. GONIADA Audouin and Edwards. Parapodia on the first third
of the body with a single lobe, on hinder part with 2 lobes: several
species, 2 in New England.

G. maculata Oersted. Body slender with about 194 segments; the
first 40 parapodia 1-lobed, the following 2-lobed; 2 principal teeth j

Fig. 465 — G-lycera
dibranchiata — an-
terior end (Verrill).
1, prostomium.

Fig. 466

Glycera

americana —

anterior end

with proboscis

extended

(Verrill).

292 ANNELIDA

length 10 cm. : Maine coast, from low- water mark to 30 fathoms, in rock
and sand; Europe.

FAMILY 9. AEICIIDAE.

Usually cylindrical worms with short knob-like tentacles and palps,
or none at all, and with filiform gills which are more or less dorsal in
position: the worm forms a tube by cementing the sand around its
burrow, the position of which can be detected by a mound at the opening ;
species not numerous.

1. ARICIA Savigny. Body short and composed of many small seg-
ments; tentacles and peristomial cirri absent; ventral cirri fimbriate or
pectinate: several species, 1 at Woods Hole.

A. ornata Verrill. Body stout and somewhat flattened; gills flat-
tened, lanceolate, and begin on the sixth segment; length up to 26 cm.;
width 7 mm.: North Carolina to Cape Cod; in shallow water.

2. SCOLOFLOS Blainville. Body usually elongate and fragile, with-
out tentacles or peristomial cirri; proboscis lobulate: several species,
3 at Woods Hole.

S. robustus (Verrill). Large worms 30 cm. long and 7 mm. wide,
with an acute head and small anterior parapodia; elongate gills begin
on segment 26; proboscis divided into about 18 long slender lobes; color
yellowish-brown : in shallow water, from North Carolina to Cape Cod.

S. fragilis (Verr.). Body 12 cm. long, 3 mm. wide; head acute, with
a 6-lobed proboscis; the gills begin to appear in segment 16; color yel-
lowish : between tide lines ; from North Carolina to Maine.

SUBORDER 2. SPIONIFORMIA.

Neither tentacles nor palps present; 1 pair of long peristomial cirri
usually present; parapodia small, the dorsal cirri often large and form-
ing gills; proboscis without jaws; worms burrowing or tubicolous: 2
families.

FAMILY 1. SPIONIDAE.

Small burrowing worms with a pair of long peristomial cirri which
usually curve over the back; dorsal cirri acting as gills; proboscis pres-
ent, but unarmed; body divided into 2 regions: in tubes in the sand, or
burrowing in wood or shells; species not numerous.

Key to the genera of Spiohidae here described.

Oj Segment 5 not enlarged.

T>! Gills on hinder half of body 1. SPIO

62 Gills absent on hinder half of body 2. LAONICE

03 Fifth segment different from the others. 3. POLYDOBA

293

1. SPIO Fabricius. Segments alike throughout; head with a promi-
nent median lobe which may be truncated or divided in front; 4 eyes;
gills on all the segments: several species, 2 at Woods Hole.

S. setosa Verrill (Fig. 467). Body long, flattened above and rounded
below ; parapodia 2-lobed ; color green ; gills and cirri red ; length 8 cm. ;
width 2.5 mm. : Long Island and Vineyard Sounds; at low-
water mark.

2. LAONICE Malmgren. Segments alike throughout;
prostomium with 2 or 4 eyes, very broad in front; gills
absent from hinder half at least of body: several species,
2 at Woods Hole.

L. (Scolecolepis Blainville) viridis (Verrill). Body
flattened; color olive green or brownish; length 10 cm.;
breadth 3 mm.: Long Island and Vineyard Sounds; near
low-water mark; often common.

3. POLYDORA Bosc. Fifth segment different from the others, being
much longer and with characteristic setae: many species, 7 at Woods
Hole.

P. concharum Verrill. Body long and slender, being 14 cm. long
and 1.5 mm. wide, with 200 segments; color grayish or yellowish: very
common from Cape Cod to Nova Scotia; in 10 to 100 fathoms, often
burrowing in shells.

FAMILY 2. CH^TOPTEEIDAE.

Worms living in U-shaped parchment-like tubes up to 50 cm. long,
buried in the sand and mud; 3 distinct regions in the body; no tentacles
or palps present and but 1 pair of peristomial cirri which tend to project
backwards; proboscis wanting: few genera and species.

CHJETOPTERUS Cuvier. Parapodia simple, consisting of large, ex-
panded notopodia in the anterior body region, but may be biramous in
the other two regions: 15 species, 1 at Woods Hole.

C. pergamentaceus Cuv. Body short and stout; anterior region
much flattened; middle region composed of 1 segment with large wing-
like parapodia and 4 swollen segments; body walls very thin, intestine
and genital products showing through; highly phosphorescent; length
15 cm.: North Carolina to Cape Cod; Europe.

SUBORDER 3. TEREBELLIFORMIA.

Prostomium a prominent lobe with or without tentacular filaments
which represent the tentacles and without palps; peristomium with or
without cirri; parapodia weak, without ventral cirri, the dorsal cirri

294

ANNELIDA

sometimes acting as gills on the anterior or all segments; no proboscis or
jaws present: 4 families; worms burrowing or tubicolous.
Key to the families of Terebelliformia:

«! Head without appendages 1. ClRRATTJLlDAE

a2 Head with long tentacular filaments.
&! Tentacular filaments very long.

Cj No setae on head 2. TEBEBELLIDAE

c2 A bundle of setae on each side of head 3. AMPHABETIDAE

62 Tentacular filaments short 4. AMPHICTENIDAE

FAMILY 1. CIKRATULIDAE.

Small and medium-sized cylindrical worms which are usually found
in burrows or under stones; head distinct but without appendages or
proboscis; parapodia rudimentary, but dorsal cirri very long and fila-
mentous and acting as gills: sev-
eral genera.

CIRRATULTJS Lamarck. Head
conical; cirri very long and slen-
der, a pair of them being present
on almost every segment; a trans-
verse row of long branchial fila-
ments on one of the anterior seg-
ments: many species, 4 at Woods
Hole.

C. cirratus (0. F. Miiller).
Head consists of a prostomium
and a peristomial segment; a row
of eyes on the prostomium; length
8 cm. ; width 4 mm. : coast of

Fig. 468 — Cirratulus grandis (Verrill).
1, dorsal cirri.

tubes under stones ;

Maine ; in

Europe.

C. grandis Verrill (Fig. 468). No eyes present; first 3 segments
without cirri; color yellowish-green; length 15 cm.; width 6 mm.; length
of longest cirri 6 to 10 cm.: Virginia to Cape Cod; in sand and gravel,
in shallow water; common.

FAMILY 2. TEBEBELLIDAE.

Long and often thick worms living in burrows or tubes; head with
a prominent horseshoe-shaped preoral lobe whose anterior margin is
reflexed, behind which is a transverse ridge bearing large numbers of
long tentacular filaments which act as gills; behind these are usually
1 to 3 pairs of branching gills belonging to the anterior segments; para-
podia reduced; both capilliform and hooked setae: numerous species.

POLYCH^ETA

295

Key to the genera of Terebellidae here described:

d Worms not filamentous ; branching gills present.
6j Three pairs of branching gills present.

GI Capilliform setae only on anterior somites 1. AMPHITRITE

ca Capilliform setae also on posterior somites 4. LEPILEA

Z>2 Two pairs of branching gills.

cx Capilliform setae begin on segment 4 2. PISTA

C2 Capilliform setae begin en segment 3 5. THELEPUS

53 But 1 gill, which has 4 branches 3. TEBEBELLIDES

az Worms filamentous and blood red ; no branching gills. /

&x Parapodia simple 6. POLYCIRBUS

62 Parapodia elongated and branched 7. ENOPLOBBANCHUS

1. AMPHITRITE 0. F. Miiller. Body cylindrical, thickest towards
the forward end; 3 pairs of branching gills; setae begin on the 4th seg-
ment and confined to anterior part of body; no eyes: many species, 4
in the Woods Hole region.

A. ornata (Leidy) (Fig. 469). Color pinkish; length up to 30 cm.,
with about 40 setigerous segments; tentacular filaments very long, nu-
merous, and contractile: North Carolina to
Cape Cod, at low-water mark; common, living
in firm tubes which are sometimes cast up on
the beach.

A. brunnea (Stimpson). Color dark red-
dish-brown; segments about 100, 25 of which
have setae; each gill with 7 to 12 branches;
length up to 18 cm.: north of Cape Cod at
low-water mark, in deeper water towards the
south.

2. PISTA Malmgren. Two pairs of branch-
ing gills; setae begin on the 4th segment and
extend to the 20th; no eyes; first 3 somites
with large ventral and lateral wings : 3 species
in the Woods Hole region.

P. palmata (Verrill). Body rather slen-
der, with 17 setigerous segments ; color reddish-
brown; length 7 cm.; width 2 mm.; animal constructs tubes of bits of
shell, etc.: Long Island and Vineyard Sounds.

3. TEREBELLIDES Sars. Two pairs of gills present which are
large and form 4 wide, comb-like branches on a single peduncle; ten-
tacular filaments numerous (over 100) : 1 species in the Woods Hole
region.

T. strcemi Sars. Body with about 60 segments and reddish in color;
length 7 cm.; width 5 mm.: Vineyard Sound to Bay of Fundy; in 10
to 250 fathoms; Europe.

Fig. 469

Amphitrite ornata (Verrill).

1. tentacular filaments

2, gills.

296 ANNELIDA

4. LEPE.S:A Malmgren. Three pairs of branching gills; setae begin
on 4th segment and extend the length of the body: several species, 1 in
the Woods Hole region.

L. rubra Verrill. Body elongate, swollen anteriorly; color bright
red; length 5 cm.; width 3 mm.: North Carolina to Vineyard Sound;
in tubes on shells, etc., below low-water mark.

5. THELEPUS Leuckart. Two pairs of branching gills; setae begin
on the 3rd segment and continue nearly or quite to the hinder end ; eyes
numerous: 1 species in the Woods Hole region.

T. cincinnatus (Fabricius). Setae extend almost to the hinder end
of the body; eyes present; length up to 12 cm.; color yellowish or red-
dish: coast of Maine to Vineyard Sound; in tubes often covered with
shells; Europe.

6. POLYCIRHUS Grube. Blood worms. Very long, slender worms
with bright-red blood ; no branching gills : several species, 2 in the Woods
Hole region.

P. eximius (Leidy). Body bright red with about 100 segments, of
which 25 bear setae: North Carolina to Cape Cod; in sand and mud in
shallow water; very common.

P. phosphorous Verrill. Brilliantly phosphorescent worms when
disturbed; length 8 cm.; first 24 segments bear setae: Long Island
Sound to Bay of Fundy.

7. ENOPLOBRANCHTJS Verrill. Blood worms. Body flattened; setae
extending to the hinder end of the body; with branched parapodia in
the middle division : 1 species.

E. sanguineus (Verr.). Body very long and slender; branched para-
podia begin on segment 12; color bright red; length 35 cm.; width 7
mm.: Virginia to Gulf of St. Lawrence; common at low-water mark; in
mud and sand.

FAMILY 3. AMPHARETIDAE.

Similar to the previous family; a bundle of setae present on each
side of the head in front of the gills; tentacular filaments small and not
numerous; no branched gills, but 4 pairs of filamentous ones present:
several genera.

AMPHARETE Malmgren. Tentacular filaments few in number;;
gills on 3rd and 4th segments: numerous species, 2 in Woods Hole;
region.

A. setosa Verrill. Body thick anteriorly, tapering backwards; 40^
tentacular filaments; color light green or red; length 20 mm.; width 3'
mm. : Long Island and Vineyard Sounds ; in rough tubes in shallow
water.

POLYCH^TA

297

FAMILY 4. AMPHICTENIDAE.

Small worms which form tubes of sand open at both ends which
can be carried about by their occupants; the prostomium bears short
filamentous tentacles which are protected by long yellow setae; hinder
end of the worm without parapodia and folded on the forward part:
several genera and few species.

PEOTINARIA Malmgren. Characters as given above: several species,
2 in the Woods Hole region.

P. gouldi (Verrill) (Fig. 470). Body flesh-color, mot-
tled ; length 4 cm. ; width 7 mm. : North Carolina to Maine ;
in shallow water.

SUBORDER 4. CAPITELLIFORMIA.

Head pointed and not distinctly set off,
without tentacles or palps but with a pair of
ciliated, retractile, tentacle-like organs; para-
podia rudimentary, with sessile capilliform
setae on the anterior and sessile hook-like
ones on the posterior segments; proboscis
without jaws : 1 family.

FAMILY CAPITELLIDAE.

With the characters of the suborder:
several genera.

1. NOTOMASTUS Sars. Prostomium con-
ical, without eyes; body composed of 2 por-
tions, a forward thicker part (thorax) consisting of about 12 biannu-
lated segments, and a long hinder portion: several species, 3 in Woods
Hole region.

N. luridus Verrill. Long, cylindrical worms, 15 cm. long, 2 mm.
thick; color dark brown: Long Island Sound to Maine; at low-water
mark in tubes in muddy sand.

N. nliformis Verr. Body filiform, 10 cm. long, 1 mm. thick; color
pale red, often mottled with whitish : Long Island and Vineyard Sounds ;
at low-water mark.

2. CAPITELLA Blainville. Large genital setae on 8th and 9th seg-
ments; thorax consisting of 9 segments; only the middle portion of the
body with setae: several species, 1 in Woods Hole region.

C. gracilis (Verrill). Length 5 cm.; color red; head trian-
gular: Cape Cod to Bay of Fundy; in tubes in the mud in shallow
water.

Fig. 470 — Pectinaria gouldi
(Verrill). A, the worm ; B, its
tube.

298 ANNELIDA

SUBORDER 5. SCOLECIFORMIA.

Head without appendages (except in the Chlorhtsmidae) ; parapodia
poorly developed or absent; proboscis present but unarmed: 6 families.
Key to the families of Scoleciformia here described:

«! Head without appendages.
&! Segmentation equivalent ; body not made up of different regions.

1. OPHETJIDAE
63 Segmentation not equivalent ; body made up of 2 or 3 more or less dis-

tinct regions.
d Worms slender and withoufgills ........................ 2. MALDANIDAE

c2 Worms thick, with branching gills on the middle segments. .3. ARENICOLIDAE
o2 Head with appendages ................................ 4. CHLOEH^EMIDAE

FAMILY 1. OPHELIIDAE.

Small burrowing worms which occur in shallow water; head with-
out appendages but with a proboscis; parapodia rudimentary, the dorsal
cirri of which are elongate and act as gills: about 6 genera.

AMMOTRYPANE Rathke. Head conical and acute;
ventral side flattened: 1 species at Woods Hole.

A. fimbriata Verrill (Fig. 471). Body elongate, being
thickest in advance of the middle and tapering to both
ends; color purplish; length 7.5 cm.; width 3 mm.: Vine-
yard Sound to Maine; in shallow water.

FAMILY 2. MALDANIDAE.

Slender, cylindrical worms which live in sand tubes;
Pig. 471 head formed of the fused prostomium and peristomium

and usually obliquely truncated by a cephalic plate and

without appendages; parapodia rudimentary, with setae
but without gills; hinder end funnel-shaped, usually with frilled edges:
7 genera.

Key to the genera of Maldanidae here described :

<LI Anus dorsal to caudal funnel ................................ 1. MAJ.DANE

o2 Anus in center of caudal funnel.
&! Anal funnel without cirri ............................... 2. CLYMENELLA

62 Anal funnel with cirri ................................... 3. NICOMACHE

1. MALDANE Grube. Body elongate, truncated at both ends, most
of the segments being biannulated; anus dorsal: numerous species,
several in the Woods Hole region.

M. urceolata (Leidy) (If. elongata Verrill). Body elongate with 19
setigerous segments, the middle ones being much elongated ; color reddish-
brown; length 30 cm.; width 5 mm.: in sandy mud at low- water mark;
North Carolina to Cape Cod.

POLTCH^TA

299

2. CLYMENELLA Verrill, Body with 18 or more setigerous segments
and with obliquely truncated head : several species, 2 in the Woods Hole
region.

C. torquata (Leidy) (Fig. 472). Body with g*^
a membranous collar arising near the middle of
the 4th setigerous segment; 22 segments, 18 with
setae; color reddish; length 10 cm.: North Caro-
lina to Bay of Fundy; in sand from low-water
mark to 60 fathoms.

3. NICOMACHE Malmgren. Funnel-shaped ter-
minal segment with marginal cirri; head without
truncating plate; prostomium sharply bent down-
wards: several species.

N. lumbricalis (Fabricius). Body slender and
fragile, consisting of 26 segments; color pink;
length 7 cm.: Cape Cod and northwards; Europe.

Fig. 472 — Clymenella
tor quota (Leidy).

A, entire worm

B, hinder end.

FAMILY 3. AEENICOLIDAE.

Elongated worms which burrow deep in the sand;
head without appendages, with an unarmed proboscis;
peristomium with a pair of lithocysts; parapodia rudi-
mentary, with branching gills above them in the middle
of the body: 1 genus.

ARENICOLA Lamarck. Anterior end blunt, the pro-
stomium and peristomium being fused together; body
cylindrical, thickest at the forward end: few species, 2
in the Woods Hole region.

A. marina (L.) (Fig. 473). Segmentation indistinct,
the skin being annulated; about 21 setigerous segments
present, of which 8 compose the anterior and 13 the
middle region, but only 4 dissepiments and 6 pairs of
nephridia; length up to 20 cm.; diameter 8 mm.: Long
Island Sound northwards; in deep burrows in the sand;
rare south of Cape Cod; Europe.

A. cristata Stimpson. Head very small; middle
branchiate region with 11 pairs of gills; color greenish-
yellow; length 35 cm. or more: Florida to Cape Cod.

FAMILY 4. CHLOEH^MIDAE. (FiG. 452, F.)

Rather small worms which live in burrows and under stones; body
not divided into regions; whole head retractile and with a circle of 3 to

Fig. 473
Arenicola

marina

(Cambridge

Natural

History).

300 ANNELIDA

20 pairs of green, short tentacular filaments which act as gills; palps
large; proboscis unarmed; blood green; setae of the anterior segments
often very long and projecting directly forwards: 6 genera.

1. TROPHONIA Milne-Edwards. Anterior setae pro-
longed, enclosing the head: 2 species in the Woods Hole
region.

T. affinis (Leidy) (Fig. 474). Body slender and
elongate; 8 tentacular filaments on head, which are blunt
and of unequal length; length 6 cm.; width 3.5 mm.:
Vineyard Sound and New Jersey; in 20 fathoms.

SUBORDER 6. SABELLIFORMIA.*

Fig. 474
Taffinis—a Prostomium more or less hidden by the forward

extension of the peristornium which usually forms a
projecting collar; tentacles rudimentary or very small;
palps very large, forming the branchial crown; proboscis present; body
consisting of 2 regions, a thorax of about 9 segments, and an abdomen;
worms tubicolous: 4 families.

Key to the families of Sdbelliformia here described:

Oi Tubes membranous ....................................... 1. SABELLIDAE

Oa Tubes calcareous ......................................... 2. SEBPULIDAE

FAMILY 1. SABELLIDAE.

Worms which live in membranous tubes in mud and sand; arising
from the prostomium is a pair of large semi-circular feathered gills rep-
resenting the palps, which may be surrounded by a collar formed of the
peristomium; tentacles rudimentary or hidden; parapodia very rudi-
mentary: many genera.

Key to the genera of Sabellidae here described :

«! Peristomial collar present.
&! Collar lobes separated dorsally .............................. 1. SABELLA

62 Collar lobes meeting dorsally .............................. 2. POTAMILLA

a2 Collar absent.
&! Worms live in gelatinous masses ; no eyes ................... 3. MYXICOLA

62 Worms live in distinct tubes ; eyes present.
ct Worms in fresh water ................................ 4. MANAYUNKIA

c2 Worms marine ........................................... 5. FABBICIA

1. SABELLA Malmgren. Gill filaments long and slender; peristo-
mium raised and reflexed to form a collar around the gills which is
notched dorsally: many species.

* See "Tubicolous Annelids of the Tribes Sabellides and Serpulides from the
Pacific Ocean," by K. J. Bush, Harriman Alaska Exp., Vol. 12, 1910.

POLTCH^ETA

301

S. microphthalma Verrill. Body short, composed of about 60 seg-
ments; anterior region composed of 8 setigerous segments; gill filaments
with minute eye spots; color greenish-yellow; length 5 cm.; diameter

3 mm. : North Carolina to Cape Cod ; at low- water mark, often incrusted
on oyster shells, etc.

2. POTAMILLA Malmgren. About 12 to 30 gill filaments on each
side, some of which have eyes at the base;

peristomial collar without a dorsal notch:
several species.

P. oculifera (Leidy) (P. reniformis
Malm.). Length 8 cm.; color greenish or
reddish-brown: New Jersey to Bay of
Fundy; on shells in tide pools; Europe.

3. MYXICOLA Koch. Body thick; hinder
region with numerous hooks in transverse
rows; gill filaments united by a mem-
branous web ; without eyes on head ; eye
spots on terminal segment; 2 small ten-
tacles: worms live in gelatinous masses
attached to shells, etc., in which each worm
has a separate tube; several species.

M. steenstrupi (Kroyer). Body thick,
with about 60 segments, of which 8 belong
to the anterior body region; color pink;
length 6 cm.; width 5 mm.: north of Cape
Cod; Europe.

4. MANAYUNKIA Leidy. About 36 gill
filaments with eyes at their bases; body
composed of but few segments: 1 species;
in fresh water.

M. speciosa Leidy (Fig. 475). Body

4 mm. long and consisting of 12 segments,
and yellowish-brown in color: in tubes on

stones in Schuylkill River, Philadelphia, also in Egg Harbor River, New
Jersey, associated with Urnatella gracilis.

5. FABRICIA Blainville. But few gill filaments or tentacles; body
composed of but few segments: few species, 1 in the Woods Hole
region.

F. leidyi Verrill. Body 3 mm. long and .2 mm. wide, consisting
of 13 segments and yellowish-brown in color; 6 gill filaments: Long
Island Sound to Bay of Fundy; in slender tubes, at and below low-
water mark.

Fig. 475
Manayunkld speciosa (Leidy).

302

ANNELIDA

projecting from its
tube (Cambridge Natu-
ral History). 1, gills;
2, operculum ; 3, col-
lar; 4, tube.

FAMILY 2. SEKPULIDAE. (FiG. 476.)

Worms which live in calcareous tubes; arising from the prostomium
are a pair of large semicircular feathered gills which represent the
palps; an operculum usually present, composed of the dorsal gill fila-
ments; just beneath the gill filaments is the
collar, a paired membrane employed in smoothing
the inside of the shell: numerous genera and
species.

Key to the genera of Serpulidae here described :

Oj Tubes incrusted on shells, etc 1. HYDROIDES

o2 Tubes minute, spiral, usually on seaweed or shells.

2. SPIRORBIS
a3 Tubes intertwining 3. FILOGRANA

Fig. 476— A serpulid i. HYDROIDES Gunnerus. Small worms living

in long contorted tubes incrusted on shells, etc.;
funnel-shaped operculum present: several species,
1 in Woods Hole region.
H. hexagonus Bosc (H. dianthus Verrill) (Fig. 477). Color of gills
variable, oftenest a purplish-brown; length 75 mm.; diameter 3 mm.:
Florida to Cape Cod; very common.

2. SPIRORBIS Daudin. A small worm living
in a tube coiled usually in a flat spiral, which is
incrusted on seaweeds, etc.; operculum present:
many species, 6 in the Woods Hole region.

S. spirorbis (L.) (S. borealis Daudin). Coiled
tube 3 mm. across; length of animal 3 mm.; 9
gill filaments present; color of gills greenish-
white: Long Island Sound to Bay of Fundy and
northwards.

3. FILOGRANA Oken. Small worms living in slender white tubes
which intertwine, forming masses 7 cm. high; 8 gill filaments present:
1 species in Woods Hole region.

F. implexa Berkeley. Body compressed, 4 mm. long; tubes very
thin; color purple or pink: Maine to Vineyard Sound; Europe.

SUBORDER 7. HERMELLIFORMIA.

Peristomium very much enlarged and forming a setigerous bilobed
hood enclosing the prostomium, which bears a pair of tentacles and a
pair of palps ; the latter are fused with the ventral edges of the peristo-
mium and project in the form of numerous gill filaments from the hood ;
body composed of 2 regions, a thorax and a long tail-like abdomen which
has no parapodia and folds back on the thorax : 1 family and few species.

Fig. 477

Hydroides hexagonus
(Hargitt) on a shell.

OLIGOCH^TA

303

FAMILY HEEMELLIDAE.

With the characters of the suborder : 3 genera.

SABELLARIA Lamarck. With the characters of the suborder: sev-
eral species, 1 at Woods Hole.

S. vulgaris Venill. Color yellowish or reddish ; length 3 cm. ; width
2.5 mm.: North Carolina to Cape Cod; from low-water mark to 10
fathoms; common in tubes of sand, also on shells.

ORDER 2. OLIGOCKETA.*

Mostly fresh-water or terrestrial,
hermaphroditic annelids which are with-
out parapodia and cephalic appendages
(Fig. 478). The setae are few in num-
ber and project from pits in the body
wall; in the Discodrilidae and Anachceta
they are wanting. Some oligocha3ts have
external gills (a few naids and tubificids).
The head is small and consists of the
prostomium, which is a small projection
in front of the mouth, and the peristo-
mium, which contains the mouth and
often appears dorsally like the first somite
of the trunk, but differs from the somites
in that it has no setae.

Paired ovaries and testes are pres-
ent (Fig. 479) ; a number of large
sperm sacs or vesiculae seminales act as
reservoirs of the sperm, in which the
sperm ripens as it comes from the testes,
and one or more pairs of pockets called
the receptacula seminis or spermathecae
receive the sperm of another animal dur-
ing the act of pairing. The eggs and sperm are extruded into a capsule
called the cocoon which is secreted by a thickened portion of the integu-
ment called the clitellum. Development is direct, the young animal being
born with the form of the parent ; of the numerous eggs in a cocoon only
a few, sometimes only one, hatch out. Many oligochaets reproduce asex-
ually, by transverse division, and the regenerative powers of all are great.

* See "A Monograph of the Order Oligochaeta," by F. Beddard, 1893. "Notes on
Species of North American Oligochaeta," by F. Smith, Bull. 111. St. Lab., Vol. 4, p. 285,
1895. "Notes on Species of N. A. Oligochaeta, II," by same, same jour., Vol. 4, p.

Fig. 478

Fig. 479

Fig. 478 — Diagram of the an-
terior portion of an earthworm,
Lumbricus terrestris (Sedgwick
and Wilson). 1, prostoraium ; 2,
mouth ; 3, openings of the sper-
mathecae ; 4, openings of the ovi-
ducts ; 5, openings of the sperm
ducts ; 6, clitellum. Fig. 479 —
Diagram of the anterior portion
of an oligochaet (an enchytraeid),

showing the internal organs with

1 the rigl
hand male organs and the left-

the digestive tract and the right-

hand female organs removed (Gal-
loway). 1, prostomium ; 2, brain;
3, mouth ; 4, ventral nerve chord;
5, spermathecae; 6, nephridium;
7. testis ; 8, clitellum ; 9, sperm
duct ; 10, ovary ; 11, sperm sac ;
12, oviduct ; 13, egg sac.

304 ANNELIDA

Oligochasts are poorly provided with special sense organs. Pig-
ment eyes are present in certain naids; tactile cells and processes may
be present but tentacles never are. The forward part of the body of
earthworms is especially sensitive to light and other stimuli.

The terrestrial oligochaets are the earthworms. These familiar ani-
mals are often of large size, the largest being six feet in length, and
are found in temperate and tropical countries in all parts of the world.
They are nocturnal animals which live in burrows in the soil and feed
on decaying vegetation and the organic particles in the soil, which they
pass in large quantities through the intestine. Darwin has estimated
that an acre of ordinary ground will have about 63,000 earthworms
which bring many tons of earth to the surface from a foot or two
beneath. They are thus important agents in renewing the surface soil.
The aquatic oligochasts live mostly at the bottom of fresh-water
streams and ponds, although a few live in the sea, often in tubes of
mud or sand, and eat aquatic vegetation. The order contains over 1,200
species and about 11 families.

Key to the families of Oligochceta here described:

«! Worms microscopic 1. ^EOLOSOMATIDAE

c2 Worms not microscopic.

&! Parasitic worms with terminal sucker 2. DISCODRILIDAE

62 No sucker present.

cx Worms very long and filiform 3. HAPLOTAXIDAE

C2 Worms not so formed.

dl Worms usually very small and slender and mostly aquatic.
d Reproduction mostly by serial budding, animal chains being formed.

5. NAIDIDAE

e2 Such reproduction not present, or at least uncommon.
/! Spermatheca far forward, usually opening in segment 4 or 5.
/2 Spermatheca farther back. 4- ENCHYTB^IDAE

0! Setae usually more than 2 in a bundle and usually of more than

one form 6. TUBIFICIDAE

gz Setae paired and all of one form 7. LUMBRICULIDAE

d2 Worms large and mostly terrestrial ; earthworms.
Ci Clitellum begins before segment 18 and contains the male pores.
/! Male pores in hinder margin of clitellum or entirely behind it.

8. MEGASCOLICIDAE

/2 Male pores in forward portion of clitellum 9. GEOSCOLECIDAE

ea Clitellum begins at or behind segment 18 ; male pores some distance

in front of it 10. LUMBBICIDAE

396, 1895. "Notes on Species," etc., by same, same jour., Vol. 5, p. 441, 1900. "Notes
on Species of N. A. Oligochaeta, IV," by same, same jour., Vol. 5, p. 459, 1900.
"Oligochaeta," by W. Michaelsen, Das Tierreich, 1900. "Researches in American
Oligochaeta," etc., by G. Eisen, Proc. Cal. Acad. Sci., 3d Ser., Zool., Vol. 2, 1900.
"Hirudinea and Oligochaeta Collected in the Great Lake Region," by J. P. Moore,
Bull. U. S. Fish. Com., Vol. 25, p. 155, 1905. "Some Marine Oligochaeta of New
England," by J. P. Moore, Proc. A. N. S., Phila., 1905, p. 373. "Die Susswasserfauna
Deutschlands," Heft 13, "Oligochseta," by W. Michaelsen, 1909. "The Common
Freshwater Oligochaeta of the United States," by T. W. Galloway, Trans. Am. Mic.
Soc., Vol. 30, p. 285, 1911.

OLIGOCHJSTA 305

FAMILY 1. ^EOLOSOMATIDAE.

Microscopic fresh-water worms usually with brown, red, or yellow
oil globules in integument, giving them a spotted appearance; no dis-
sepiments present; setae in 4 bundles in each segment, of 1 to 6 setae
each ; clitellum only on ventral side on segments
5 to 7; nervous system hypodermic; prostomium
ciliated ventrally; the most primitive oligo-
chaets, reproducing by division: 1 genus.

.ffioLOSOMA Ehrenberg. With the characters
of the family: about 9 species, 5 in this
country.

A. quaternarium Ehr. (Fig. 480) (A. venu-
stum Leidy). Head of same width as body;
setae sharply bent, those of the same bundle of
the same length; the worm encysts itself; spots
red; length 1 mm., with 7 to 10 segments:
among algae.

A. hemprichi Ehr. Head broader than body; setae nearly straight;
spots red or crimson; length 2 to 5 mm., with 4 to 13 segments: among

algae.

FAMILY 2. DISCODEILIDAE.

Small parasitic oligochaets which were formerly grouped with the
Hirudinea, with a sucker at the hinder end of the body and without
setae, which live on the gills or the outer surface of crayfish ; mouth with
a dorsal and a ventral chitinous jaw; anus dorsal; 2 pairs of nephridia;
1 or 2 pairs testes ; single median genital pore in sixth segment : several
genera.

Key to the genera of Discodrilidae here described:

«! One pair testes 1. BBANCHIOBDELLA

aa Two pairs testes.

Z>! No dorsal appendages 2. BDEIXODRILTJS

62 Dorsal appendages present 3. PTEEODRILUS

1. BRANCHIOBDELLA* Odier. Dorsal and ventral jaws similar; 1
pair testes in fifth segment: 3 American species.

B. pulcherrima Moore. Body 6 mm. long and 1.3 mm. wide, very-
transparent forward and somewhat flattened; eighth and ninth s.eg-r.
ments flattened, each with a pair of adhesive organs : North Carolina.

B. instabilia Moore. Body 5..5 mm. long, 1.3 mm*, wide; hinder 4
segments forming a flattened disc-shaped expansion which is almost as
wide as long, anterior segment very contractile : eastern states.

*= See "On Some Leechlike Parasites of American Crayfishes," by J. P. Moore,
Proc. Ac. Nat. Sci., Phila., 1893, p. 419. "Notes on BrancWobdeUa," by W, M,

L sun.,, yoi, ti,; o. 100, 190,6..

306

ANNELIDA

2. BDELLODRILTJS Moore. Two pairs of testes and sperm ducts: 2
species.

B. illuminatus (Moore) (Fig. 481). Body 4 mm. long and .9 mm.
wide, the head being composed of 4 segments, the trunk of 11, all being

biannulated ; clitellum is the dorsum of segment
6: often common on the gills of crayfish; co-
coons also on the gills; eastern North America.
B. philadelphicus (Leidy). Head the
broadest part of the body ; length 10 mm. : on
the external (usually the ventral) surface of
crayfish; eastern and central North America.

3. PTERODRILTTS Moore. Two pairs of testes and sperm ducts; long
paired, dorsal appendages on certain of the body segments: 2 species.

P. distichus Moore (Fig. 482).
Dorsal appendages not branched;
length 1 mm.: on the external sur-
face of the crayfish in western
New York.

FAMILY 3. HAPLOTAXIDAE.

Fig. 481

Bdellodrilus illuminatus
(Moore).

Fig. 482

Pterodrilus distichus
(Moore).

Body very long and slender or
filamentous; setae sigmoid, single

or paired, in 4 rows ; 2 pairs of ovaries ; central blood vessel contractile :
2 genera and 3 species.

HAPLOTAXIS Hoffmeister. Clitellum on segments 11
to 14; 2 pair male pores on segments 11 and 12: 2 species.
H. gordioides Hartmann (H. emissarius Forbes) (Fig.
483). Dorsal setae absent on the hinder four-fifths of
body; length 18 cm. and more; width .6 mm.; 375 seg-
ments: in wet ground or in the water (Illinois; Phila-
delphia) .

FAMILY 4. ENCHYTKJEIDAE.*

Fig 483 More or less slender worms 30 mm. or less in length

Hordioides which live in fresh water along the shore of the sea or in

F^eu^) decaying or living plants; setae hair-like, in 4 bundles in

each segment; clitellum when fully developed occupies

segments 11 to 13; dorsal blood vessel arises near the clitellum; testes

and ovaries in segments 11 and 12: about 13 genera and 170 species.

* See "Enchytrseidae of the West Coast of North America," by G. Eisen, Harrt-
man Alaska Exp., Vol., 12, 1910,

OLIGOCH^TA 307

Key to the genera of Enchytraidae here described:

Oi Setae straight, or nearly so.

&! All setae in a bundle of equal length 1. ENCHYTB^EUS

&2 Setae not all of equal length, inner setae of each bundle smaller than

outer 2. FEIDEBICIA

oa Setae sigmoid.

&x Blood yellow or red ; testes massive 2. LUMBBICILLUS

62 Blood usually colorless ; testes subdivided 4. MESENCHYTB^EUS

1. ENCHYTR^TTS Henle. Setae straight or nearly so, all those in a
bundle of equal length (Fig. 484); blood colorless; large salivary glands
present: 10 species.

E. albidus Henle. Milk-white worms 25 mm. long and 1 mm. thick;
setae nearly straight but hooked at inner end 2 to 6 in a bundle; num-
ber of segments 53 to 69 : New Jersey to Maine, along the seashore near
high-water mark under decaying seaweed and stones, also inland near
the shore; very common in Europe and America.

E. socialis Leidy. Body translucent and 20 mm. long; setae 5 to 7
in a bundle ; mouth triangular : in groups, in rotten stumps and logs.

Fig. 484 Fig. 485 Fig. 486

Fig. 484 — Setae of Enchytrceus (Siissw. F. Deut.). Fig. 485 — Setae of Lumbricillus
(Stissw. F. Deut.). Fig. 486 — Setae of Fridericia (Siissw. F. Deut.).

2. LUMBRICILLUS Oersted (Fig. 485). Setae sigmoid; testes mas-
sive; blood yellow or red; no salivary glands; clitellum covers segments
.11 and 12: 15 species.

L. agilis Moore. Transparent worms with pink or brown internal
organs, 16 mm. long and .4 mm. thick: Maine to Vineyard Sound, along
the seashore under seaweed near high-water mark.

3. FRIDERICIA Michaelsen (Fig. 486). Setae straight, 2 to 6 in a
bundle and not of equal length, the inner setae of a bundle being shorter
than the outer; blood colorless; salivary glands present: 21 species, 6
in this country.

F. alba Moore. Length 22 mm.; number of segments 58; sper-
matheca simple; salivary glands branched; setae long and slender: in
wet moss and leaves in the woods.

F. parva Moore. Length 16 mm.; number of segments 46; sper-
matheca and salivary glands unbranched; 4 setae in a bundle as far as

308

ANNELIDA

segment 25, then 2; color opaline white: among damp leaves, in the
woods.

F. agilis Smith. Length 30 mm.; number of segments 57 to 66;
dorsal blood vessel begins at segment 19 ; salivary glands much branched :
in the soil (Illinois).

4. MESENCHYTIUETTS Eisen. Setae sigmoid; blood usually colorless;

no salivary glands: 30 species.

M. bemneri (Michaelsen). Length
30 mm. ; setae 3 to 5 in lateral bundles
and 5 to 8 in ventral ones; clitellum
on segments 11 to 13: Philadelphia,
in wet places; Europe.

Fig. 487 — Diagram of anterior por-
tion of a naid (Walton). 1, prosto-
mium ; 2, eye ; 3, brain ; 4, mouth ;
5, pharynx ; 6, O3sophagus ; 7, blood
vessel ; 8, testis ; 9, ovary ; 10, hair-
like setae; 11, forked setae; 12, in-
testine ; 13, clitellum.

FAMILY 5. NAIDIDAE.'

Small aquatic, transparent worms
(Fig. 487) with 2 to 4 groups of setae
on each segment, and often with a

distinct head; ventral setae forked; testes and ovaries usually in seg-
ments 5 to 7; the worms reproduce principally by transverse division,
forming animal chains : 15 genera and 50 species, mostly in fresh water.
Key to the genera of Naididae here described:

ax Hair-like setae present dorsally.

Z>! Prostomium not tentacular.

Cj Without retractile rear appendages 1. NAIS

c2 Retractile rear appendages present 4. DEBO

62 Prostomium long and tentacular.

Cj Dorsal setae begin on 5th or 6th segment 2. STYLABIA

c2 Dorsal setae begin on 2d segment 5. PBISTINA

a, Hair-like setae absent dorsally.

&! No dorsal setae present 6. CIOSTOGASTEB

&2 Forked dorsal setae present 3. PABANAIS

1. NAIS 0. F. Miiller. Head distinct ; dorsal setae begin on segment
6 and are partly acicular and partly long and hair-like; ventral setae
short, with cleft ends; blood yellow or red; eyes usually present: in
standing or flowing water, in mud or on plants; reproduction by budding
very common; 10 species, 5 American.

N. elinguis Mull. (N. rivulosa Leidy). Two or 3 dorsal hair-like
setae present; length 2 to 10 mm., with 15 to 37 segments; color light
brown; eyes usually present: often abundant on algae; Europe.

N. parvula Walton. Prostomium blunt; eyes present; dorsal bundle
composed of 1 hair-like and 2 cleft setae; length 1.2 mm.: Cedar Point,
Lake Erie.

* See "Naididae of Cedar Point," by L. B. Walton, Am. Nat, Vol. 40, p. 683, 1906.

OLIGOCH^TA

309

Fig. 488
Stylaria
lacustris
(Walton).

2. STYLARIA Lamarck. Prostomium very long and tentacle-like;
setae as in Nais : 2 species, in Europe and America.

5. lacustris (L.) (Fig. 488). Length 15 mm., with 25 segments:
common; Europe.

3. PARANAIS Czerniavsky. Head distinct; setae all
forked; dorsal setae begin on segment 5; no eyes: 3
species.

P. litoralis (0. F. Miiller) (Enchytr&us triventralo-
pectinatus Minor). Length 10 mm.; segments about 20;
blood greenish-yellow: Long Island and Vineyard Sounds,
under stones or decaying vegetation near high-water mark
on the seashore, also in fresh water; often very common;
Europe.

4. DERO Oken. Setae as in Nais; ciliated branchial
appendages extend from the funnel-shaped rear end;
blood reddish; no eyes: 15 species, 4 in America; often
in tubes.

D. limosa Leidy. Length 12 mm. or less with about
48 segments; color reddish: in tubes at the bottom of stagnant pools
and among algae; common; Europe.

D. obtusa Udekem. Length 10 mm. ; a long and a short seta in each
dorsal bundle: Illinois; Europe.

D. vaga Leidy (Fig. 489). Length 8 mm.;
number of segments 25 to 35; body ending in 2
long finger-like processes: often very common.
5. PRISTINA Ehrenberg. Dorsal setae all
hair-like and begin in second segment; ventral
setae all forked; prostomium very long and re-
tractile; rear end sometimes with long projec-
tions; no eyes: 8 species, 3 American.

P. leidyi Smith. Length 8 mm., diameter .15
mm., with about 30 segments; 3 setae in each
dorsal bundle, 5 to 9 in each ventral bundle;
clitellum on segments 7 to 9 : in streams and lakes
in the eastern and central states; common.

P. serpentina Walton (Fig. 490). Length 2.2
mm. with about 22 segments; dorsal bundle with
5 to 9 setae, ventral bundle with 5 or 6: very common; Cedar Point,
Lake Erie.

6. CHJETOGASTER von Baer. Very transparent worms with 2 bundles
of hooked setae on the ventral side of each segment and no dorsal setae;
blood colorless : 6 species, 5 American.

Fig. 489

Fig. 490

Fig. 489
Dero vaga (Walton).

Fig. 490

Pristina serpentina
(Walton).

310 ANNELIDA

C. limnaei von Baer (Fig. 491). Anterior bundles of setae with 10
to 20 each; length 5 mm.: eastern states, usually found on Lymncea and
Planorbis or parasitic in their liver; also free-living; common; Europe.

C. pellucidus Walton. Setae forked, 6 to 7
in a bundle; length 1.5 mm.: Cedar Point, Lake
Erie; common.

FAMILY 6. TUBIFICIDAE.
limncei(S\issvf, F.'Deut.)

Slender, red or brown worms living in fresh

or brackish water in tubes from which they protrude the hinder end; 4
bundles of setae on each segment; testes and ovaries in segments 10 or
11; but 1 pair of sperm ducts; no reproduction by division; clitellum on
segments 11 and 12: about 14 genera and 50 species.
Key to the genera of Tubificidae here described :

ox Dorsal setae both forked and hair-like 1. TUBIFEX

az Dorsal setae all forked.

&! Setae of segment 11 modified 3. BOTHHIONEUEUM

&2 These setae not modified.

<?! No blood capillaries in body wall 2. CLITELLIO

c2 Capillaries in body wall 4. LIMNODRILUS

1. TUBIFEX Lamarck. Forked and usually hair-like setae in the
dorsal bundles; usually forked setae alone in the ventral bundles; con-
tractile hearts in segment 8: several species.

T. irroratus (Verrill) (Clitellio irroratus Verr.). Pink or brown
worms 3 cm. long; prostomium acute: near high- water mark south of
Cape Cod on the seashore.

T. benedeni Udekem. Gray or black worms ; cutie-
ula studded irregularly with flattened papillae; length
4 cm. : Long Island Sound to Maine, near high-water
mark on the seashore.

T. tubifex (0. F. Muller) (Fig. 492). Reddish

. , tae with middle

worms about 4 cm. long with about 60 segments; the teeth (Stissw. F.

forked setae in dorsal bundles in front of the clitellum
have 1 to 3 middle teeth; ventral setae all forked: in mud in standing
and running fresh water; often common, forming reddish patches on the
mud where they are seen waving their hinder ends in the water; Europe.

2. CLITELLIO Savigny. Forked setae alone present; contractile
hearts in segments 8 and 9; no blood capillaries in body wall; prostate
glands diffuse: 1 species.

C. arenarius (0. F. Muller) (C. irroratus Verrill). Body very slen-
der and reddish, up to 6 cm. long; setae sigmoid: Long Island Sound
to Maine, often very common under rocks and stones near high-water
mark on the seashore; Europe.

OLIGOCH^STA 311

3. BOTHRIONETTRTJM Stole. Forked setae alone present; ventral
setae of segment 11 modified for copulatory purposes: several species.

B. glaber Moore. Body pinkish or brown, 4 cm. long- and .8 mm.
wide; setae short and forked at the end: Vineyard Sound, under decay-
ing vegetation and stones near high-water mark, especially where the
water is brackish.

4. LIMNODRILUS Claparede. Forked setae alone present; contrac-
tile hearts in segment 8 and 9 ; blood capillaries penetrate the body wall ;
prostate gland large and massive, in segment 11: about 10 species, in
fresh water.

L. claparedianus Ratzel. Length 4 to 7 cm.; segments 150: eastern
states, in fresh water.

L. subsalsus Moore. Body red or brown in color and 4 cm. long;
segments 120; setae deeply bifid, 4 to 6 being in each group before and
2 to 4 behind the clitellum : in brackish water at New Bedford, Mass.

FAMILY 7. LUMBRICULIDAE.

Small worms usually red or brown in color, living in mud in fresh
water; 2 pairs of dorsal and 2 of ventral setae in each segment; 2 pairs
of sperm ducts, but with 1 pair of openings: 8 genera and about 15
species.

1. TRICHODRILTTS Claparede (Tliinodrilus Smith). Setae simple or
forked at the end; dorsal blood vessel with paired contractile, blind
appendages ; male pores in segment 10 : 3 species.

T. inconstans (Smith). Length 6 cm.; width 8 mm.; color reddish,
a nteriorly greenish ; 5 pairs of small spermathecae : in mud or vegetation
in fresh water.

FAMILY 8. MEGASCOLICIDAE.

Usually terrestrial, sometimes aquatic oligochasts; setae curved, 8,
12, or more on a segment; male pores on segment 18 or 17; clitellum
beginning on or before segment 16, not appearing excepting at certain
times and without sharp boundaries: 56 genera and about 600 species,
principally in the southern hemisphere and the tropical portions of the
northern.

1. DIPLOCARDIA Garman. Setae paired, 8 on a segment, absent on
segment 18; clitellum on segment 13 to 18: about 10 species, all
American.

D. communis* Gar. Length 30 cm.; diameter 3 mm.; flesh-colored;
dorsal vessel double ; 3 pairs of spermathecae in segments 7 to 9 : in the
soil of the prairies (Illinois).

* See "On the Anatomy and Histology of a New Earthworm (Diplocardia com'
munis)," by*H. Garman, Bull, of 111. St. Lab. of Nat. Hist.. Vol. 3, p. 47, 1892.

312 ANNELIDA

D. riparia Smith. Length 25 cm.; diameter 3 mm.; color brown;
dorsal vessel single ; 2 pairs of spermathecae, in segment 8 and 9 : in wet
forest soil (Illinois).

FAMILY 9. GEOSCOLECIDAE.

Aquatic or terrestrial, usually tropical oligocha3ts with 8 curved
setae in a segment, paired or not; clitellum concave ventrally; male
pores just before or in clitellum; gizzard in middle of oesophagus: 20
genera and about 90 species.

SPARGANOPHILUS Benham. Prostomium not marked off from peri-
stomium; clitellum in segments 15 to 25; male pores on segment 19; 4
pairs of setae on a segment, a pair on each corner of the quadrangular
cross section : in the mud of streams ; 4 species.

S. eiseni Smith. Length 20 cm.; diameter 2.6 mm.; dorsal setae
project laterally beyond the ventral; a pair of large glands open on seg-
ment 3; central and western states, in mud of springs.

S. tamesis Benham. Length 10 cm. ; color red or blue; ventral setae
project laterally beyond the dorsal: Philadelphia; England; on water
plants.

FAMILY 10. LUMBEICIDAE.

Earthworms. Terrestrial, occasionally aquatic, oligochaets with 4
pairs of setae to a segment; elitellum concave ventrally, not beginning
before segment 18 or after segment 61; male genital pores on segment
15 (rarely on segments 11 to 14) ; 2 pairs of testes in segments 10 and 11
(rarely 1 pair); 1 pair of ovaries in segment 13; cocoons egg-shaped:
5 genera and over 100 species.

Key to the genera of Lumbriddae here described:

Oj Peristomium completely divided dorsally by prostomium (Fig. 493).

1. LUMBBICUS

o2 Peristomium incompletely divided by prostomium (Fig. 494).
&! Gizzard occupies more than 1 segment ; clitellum reaches at least through
segment 32.

Ci Clitellum begins mostly on segment 24 2. EISENIA

c2 Clitellum begins mostly behind segment 24 3. HELODRILUS

62 Gizzard occupies but 1 segment ; clitellum reaches at most to segment

27 4. ElSENIELLA

1. LUMBRICUS L. Peristomium (buccal segment) completely divided
by prostomium (Fig. 493); setae strictly paired; 3 pair vesiculae semi-
nales present in segments 10 and 11 which fuse together in the middle
line; 2 pairs of spermathecae, in segments 9 and 10; tail end flattened:
8 species, 3 American.

OLIGOCH&TA 313

Key to the American species of Lumbricus :

G! Clitellum on segments 31 or 32 to 37 L. TEBRESTRIS

o2 Clitellum on segments 26 or 27 to 32 L. RUBELLUS

aa Clitellum on segments 28 to 33 L. CASTANEUS

L. terrestris L. (Fig. 478). Length up to 30 cm., with about 180
segments; color purplish; clitellum on segments 31 or 32 to 37: in wet
places; Europe and America.

L. rubellus Hoffmeister. Length up to 15 cm. with about 150 seg-
ments; color pink; clitellum on segments 26 or 27 to 32, usually nearly
in center of body : in wet places ; cosmopolitan.

L. castaneus (Savigny). Length up to 5 cm. with about 90 seg-
ments; color chestnut or violet brown, strongly iridescent; clitellum
on segments 28 to 33: America and
Europe.

2. EISENIA Malmgren (Allolobophora
Eisen) (Fig. 494). Peristomium incom-

pletely divided by prostomium ; 3 or 4 Fig. 493 Fig. 494

pairs of vesiculae seminales which do Fig 493 — Diagram showing

not fuse together in the middle line; 2 ?$£$?**.

or 3 pairs spermathecae in segments 8 to

11; tail end cylindrical: 9 species, 3 {£$!£ Perist°mium <Siissw- F-

American.

E. foetida (Savigny). Length up to 9 cm. with about 100 segments;
color pink with a dark ring on each segment; clitellum on segments 24,
25, or 26 to 32; setae strictly in pairs; 2 pairs spermathecae, in segments
9 and 10: the worm lives often in manure and has a disagreeable odor;
cosmopolitan.

E. rosea (Sav.). Length up to 6 cm. with about 150 segments;
color red; clitellum on segments 24, 25, or 26 to 32; 2 pairs of sper-
mathecae in segments 10 and 11; setae strictly paired: in wet places;
cosmopolitan.

3. HELODRILUS Hoffmeister (Allolobophora Eisen). Peristomium
incompletely divided by prostomium (Fig. 494) ; 2 to 4 pairs vesiculae
seminales which do not fuse together in the middle line; tail end cylin-
drical: 54 species, 10 American.

H. caliginosus (Savigny). Length up to 17 cm. with about 250 nar-
row segments ; color very variable, being gray, pink, yellowish, or bluish,
but never purple; clitellum on segments 27 or 28 to 35; setae strictly
paired; 4 pairs vesiculae seminales; 2 pairs spermatheeae : in fields and
gardens ; cosmopolitan.

H. chloroticus (Sav.). Length up to 6 cm. with about 125 seg-
ments; color variable, but never purple; clitellum on segments 29 to 37;

314 ANNELIDA

setae in pairs, close together; 3 pairs of spermathecae in segments
9, 10, 11; 4 pairs vesiculae seminales: terrestrial; cosmopolitan.

H. palustris* (H. F. Moore). Length 7 cm.; segments 100; color
red; clitellum on segments 23 to 28; 2 pairs vesiculae seminales; no
spermathecae: Pennsylvania to North Carolina; in wet soil.

4. EISENIELLA Michaelsen (Allurus Eisen; Allolobophora Eisen).
Peristomium incompletely divided by prostomium (Fig. 494), clitellum
beginning with the segment 23 or in front of it ; male pores on segment
11 to 15; gizzard confined to segment 17; 4 pairs vesiculae seminales,
which do not fuse in the middle line: 2 species.

E. tetrsedra (Savigny). Color yellow, brown, or blackish; hinder
and middle portions of body rectangular ; length 5 cm. ; thickness 4 mm. ;
segments 90; male pores on segment 13, female pores on segment 14;
clitellum on segments 22 or 23 to 27: cosmopolitan; in wet soil.

ORDER 3. ECHIURIDA.f

Thick-bodied, cylindrical annelids in which the segmentation is
wanting or indistinct in the adult. The animals are, however, born as
typical trochophore larvae and at an early period of the metamorphosis
have fifteen rudimentary somites. Parapodia and cephalic appendages
are wanting. A pair of large setae is present on the ventral side near
the forward end; in Echiurus two groups of setae are also present at the
hinder end.

The formation of the head is peculiar. The prostomium is very
much elongated and forms a long spatulate or trough-like structure in
front of the mouth, which may be very elastic and forked at the end.
The grooved ventral surface of the prostomium is ciliated and in it the
minute animals which constitute the food of the worm are swept into
the mouth. The prostomium is called the proboscis.

The alimentary canal is much longer than the body and terminates
with the anus at the hinder end; joining the rectum is a pair of long
cylindrical anal pouches which communicate with the body cavity and
are modified nephridia. From one to three pair of typical nephridia are
also present in the forward part of the body. The vascular system con-
sists of a dorsal and a ventral longitudinal blood vessel, which join each
other anteriorly, and no lateral vessels. The nervous system includes
a ventral chord which is segmented in the early developmental stages
but unsegmented in the adult. A distinct brain is wanting, but an

* See "On the Structure of Bimastus palustris, a New Oligochsete," by H. F.
Moore, Jour. Morph., Vol. 10, p. 473, 1895.

f See "Thallasema mellita," by H. W. Conn, Stud. Biol. Lab., J. H. U., Vol. 3,
1884. "North American Echiurids," by C. B. Wilson, Biol. Bull., Vol. 1, p. 163, 1900.

ECHIURIDA

315

cesophageal ring is present which is much elongated, as it extends from
the front end of the prostomium to the ventral chord back of the mouth.
Special sense organs are wanting but the prostomium acts as a feeler.

The animals are unisexual, the gonad being unpaired but

the ducts paired.

The EcMurida are marine worms which live in the

sand and mud or between stones, usually near the shore.

The order contains about 20 species and 5 genera, 3 genera

and 5 species being known on the Atlantic and 1 species

on the Pacific coast.

Key to the genera of EcMurida here described:

«! Preanal bristles present 1. EcmuBUS

oa No preanal bristles 2. THALASSEMA

1. ECHITTRUS Cuvier. Preanal bristles and 2 ventral
hooks present; body marked with rings bearing spines;
2 or 3 pairs of nephridia: 3 species.

E. pallasi Guerin (E. chrysacanthophorus Pourtales)
(Fig. 495). Proboscis spoon-shaped but cylindrical at
base; about 22 body rings present; color gray, yellow, or
orange; length 30 cm. or less; length of proboscis 6 cm.;
width 6 cm.: North Atlantic (Casco Bay) and Alaska;
Europe.

2. THALASSEMA Gaertner. Proboscis rather pointed at
end; no preanal bristles but 2 ventral hooks present; 1 to
4 pairs of nephridia : 12 species.

T. melitta Conn (Fig. 496). Color dull red with 8 lon-
gitudinal bands; proboscis light yellow; length 25 mm., Thaiassema
exclusive of proboscis, which is long and flexible: (original)
Beaufort, N. C., often in sand-dollar shells. H. W. Conn).

CLASS 3. HIRUDINEA.*

Leeches (Fig. 501). Dorso-ventrally flattened, often brightly col-
ored annelids, which are completely segmented internally and are marked
externally with three or more rings to each somite. A large sucker is
present at the hinder and a small one at the forward end by means of
which the animal moves on hard surfaces. Parapodia, tentacles, and setae

* See Leeches of the TJ. S. Nat. Museum," by J. P. Moore, Proc. U. S. Nat. Mus.,
Vol. 21, p. 543, 1898. "The Hirudinea of Illinois," by J. P. Moore, Bull. 111. St. Lab.,
Vol. 5, p. 479, 1901. "Notes on the Leeches of Nebraska," by H. B. Ward, Studies
from the Zool. Lab. Neb., No. 51. "Hirudinea and Oligochaeta Collected in the Great
Lake Region," by J. P. Moore, Bull. U. S. Fish. Bur., Vol. 26, p. 155, 1905. "Die
Siisswasserfauna Deutschlands, Hirudinea," by L. Johansson, 1909. "The Leeches of
Minnesota," by J. P. Moore, Part III, Geog. and Geol. Sur. Minn., 1912.

316 ANNELIDA

are wanting. Acanthobdella, a Russian fresh-water leech, is an exception
to this rule, having setae on the first five somites. Paired gills are present
in a few genera. The head is not distinctly marked off from the trunk
but the prostomium projects in front of the mouth, as in the Oligochata.
The body cavity differs in character from that in most other annelids in
that it is filled secondarily with a vacuolated parenchyma; several tube-
like spaces are, however, still left in it which are connected with the
vascular system and contain blood.

The mouth is ventral or subtermihal in position and opens into a
pharynx which is provided with salivary glands and in turn leads into
the oesophagus and the targe crop; this organ has paired segmental
pouches and passes back to the stomach, which may also be provided
with paired pouches. The short intestine passes to the
anus at the hinder end of the body above the sucker.
The pharynx (Fig. 497) is provided with three serrated
chitinous plates in the medicinal leech and its allies, by
means of which the animal may draw blood from the
body of its host. The Rhynchobdellidae, on the other
hand, have no such plates but a proboscis which can be
thrust out of the mouth and be made to pierce the skin
of another animal. The main vascular system consists
in general of four longitudinal blood vessels, a dorsal, a
anterior end~o£ ventral, and two lateral. The excretory system consists
feech1;6 B,Cante- of paired nephridia in the middle portion of the body
?hynchobdem<f (seventeen pairs in Hirudo), the inner 'ends opening into
i,UScMtineous the sinuses representing the body cavity. The nervous
tended probos- system is like that of other annelids. The two longi-
suck'er.8' °ral tudinal nerves are close together and several of the
anterior ganglion pairs are fused together forming an
infra-03sophageal ganglion. The special sense organs consist of a number
of pairs of eyes (in Hirudo five) at the forward end of the body and sense
buds which are most numerous at the forward end.

The leeches are hermaphroditic. A number of pairs of testes alter-
nate usually with the segmental lateral pouches of the digestive tract
and communicate with a pair of vasa deferentia which proceed to the
male genital pore in the anterior part of the body, joining to form a
penis at their anterior end. The female pore lies just behind the male;
two ovaries are present which are joined by the oviducts with the vagina.
Fertilization is effected by means of a spermatophore and the eggs are
usually laid in a cocoon formed by a clitellum on the ninth, tenth, and
eleventh somites. The young animal is born with the form of the
parent.

HIRUDINEA 317

Leeches are mostly aquatic animals which live in fresh water in all
parts of the world ; a few live in the sea and a few in moist earth. They
are predacious animals, feeding on oligochaets, snails, and other small
animals and are also at times external parasites, sucking the blood of
aquatic vertebrates. The class contains two orders and about 150
species.

Key to the orders of Hirudinea:

ax Proboscis present and no jaws ; blood colorless ; somites rarely consisting

of 5 rings each 1. RHYNCHOBDELLIDA

aa No proboscis but usually 3 jaws present ; blood red ; somites usually

consisting of 5 rings each 2. GNATHOBDELLIDA

ORDER 1. RHYNCHOBDELLIDA.*

Leeches with a proboscis which can be thrust out of the mouth, and
no jaws, and with colorless blood; segments consisting of 3 or more but
rarely of 5 rings each : 2 families.

Key to the families of Rhynchobdellida:

d! Both suckers distinct from body 1. ICHTHYOBDELLIDAE

c, Hinder sucker distinct, forward sucker more or less fused with body.

2. GLOSSIPHONIIDAE

FAMILY 1. ICHTHYOBDELLIDAE.

Leeches parasitic on fishes, tortoises, and some other animals; both
suckers pedunculate; body elongate, narrow anteriorly, and broad pos-
teriorly; body segments containing more than 3 rings each: 7 genera.

Key to the genera of Ichthyobdellidae here described:

ax No gills present 1. PiSdCOLA

a2 Gills present.

61 Paired papilliform vesicles act as gills 2. CYSTOBBANCHUS

6, Paired arborescent gills present 3. BBANCHELLION

1. PISCICOLA Blainville. Body cylindrical, distinctly
annulated with many (usually 14) rings to a somite; eyes
distinct: many species.

P. rapax (Verrill) (Fig. 498). Body long and slender,
dark olive in color with a row of rectangular white spots
along each side; length 40 mm.; width 2 mm.: on the
summer flounder.

P. funduli (Verr.). Body smooth, distinctly annu-
lated, light green in color with fine dots of brown and
green; length 18 mm.; 2 large and 2 small eyes: on Fundulus
pisculentus.

* See "Some North American Freshwater Rhynchobdellida and The.ir Parasites,"
by W. E. Castle, Bull. Mus. Comp. Zool., Vol. 36, p. 17, 1900.

318 ANNELIDA

2. CYSTOBRANCHTJS Diesing. Gills present in form of paired papil-
liform vesicles along the sides of the body; body composed of 2 regions,
a narrow anterior region of 11 somites and a broad posterior region;
each segment contains 7 rings: 2 species.

C. vividus Verrill. Body with 11 pairs of vesicles, brownish or
purplish in color with 3 irregular rows of white spots on the back;
length 25 mm.; eyes 4: on Fundulus pisculentus; Long Island Sound;
also in fresh water.

3. BRANCHELLION Savigny. Gills present in form of paired
aborescent appendages; body with a slender anterior neck: several
species.

B. raveneli (Girard) (Fig. 499). Body with about 30 pairs of
gills, dark brown or purple in color; length 6 cm.: on skates and
rays.

FAMILY 2. GLOSSIPHONTIDAE.

Fresh-water leeches in which the anterior sucker is fused with the
body and the posterior sucker is distinct; each segment contains 3
rings; no cocoon is formed, the eggs and young being fixed
to the mother's body: several genera.

1. GLOSSIPHONIA Johnson (Clepsine Savigny). Body
wide, attenuated forward, often brightly
colored; animal cannot swim but rolls
up when alarmed: numerous species; in
fresh water.

G. parasitica (Say) (Clepsine plana

Whitman). Body broad and flat, with a
Fig. 499 Fig. 500 ,, »

smooth suriace; color vanegated, being
Fig. 499 — Branchellion raveneli . , ,, . ,

(Verrill). Fig. 500 — oiossiphonia greenish or yellowish, with longitudinal
complanata — anterior end showing /> •, „

eyes (Suss w. F. Deut.). rows oi spots; lower suriace longitudi-

nally striped; 2 eyes; length 6 cm.;

width 2.6 cm.: the most abundant American species; on turtles or
under stones.

G. complanata (L.) (Fig. 500). Body 30 mm. long and 10 mm.
wide, very flat; color greenish, spotted with yellow; eyes 6, in 3 pairs:
often common under stones in running water; very active; Europe.

G. fusca Castle (G. lineata Verrill). Body 12 mm. long, flat and
broad, with 12 longitudinal brown stripes; 2 large eyes: in cold
streams.

G. elegans (Verr.) (Fig. 501). Body elliptical, 18 mm. long and
7 mm. wide, brownish in color; head colorless; 6 eyes: abundant iw
shallow waters, often with G, stagnates; sluggish in its movements.

HIEUDINEA

319

Fig. 502

Olossiphonia

stagnalis

(Sussw.

F. Deut.).

G. rugosa (Verr.). Body rough and papillose; color variegated,
spotted irregularly with yellow and green; 2 eyes; length 5 cm.: abun-
dant under stones in run-
ning water.

G. stagnalis (L.)
(Fig. 502). Body small,
rather elongate, grayish
or pinkish in color, and
25 mm. long by 2 mm.
wide when extended; 10
mm. long at rest; annu-
lation distinct; 2 eyes;
between rings 12 and 13 is a con-
spicuous brown, cuticular plate; crop
with but one pair of pouches: in
ponds and sluggish streams, where it
feeds on small snails; very common;
Europe; very active in its move-
ments.

G. heteroclita (L.) (Fig. 503). Body
transparent, yellowish or brownish in
color, about 10 mm. long and 3 mm.
wide, and with indistinct rings; 6 eyes
arranged in pairs at the corners of a
triangle: in ponds and sluggish
streams ; Europe.

2. HEMICLEPSIS Vej-
dovsky. Anterior sucker
pedunculate; body wide
and flat: several species.
B. carinata Verrill.
Body 35 mm. long, rather
slender ; color greenish
with longitudinal stripes ;
eyes 2, conspicuous : com-
mon in streams, some-
times attached to frogs
or toads.

Fig. 503

Glossiphonia

heteroclita

(Siissw. F.

Deut.).

Fig. 501 — Glossiphonia elegans —
diagram showing the digestive and
genital tracts, seen from the dorsal
surface, the somites being numbered
on the left and the rings on the
right side (Castle), an., anus ; br.,
brain ; cr., crop ; in., intestine ; ov.,
ovary ; pr., proboscis ; p.s., poste-
rior sucker ; si., salivary glands ;
st., stomach ; t., testis ; d1, male
genital pore ; 9, female genital pore.

ORDER 2. GNATHOBDELLIDA.

Fresh-water and terrestrial leeches without a proboscis and usually
with 3 jaws (Fig. 497, A) ; blood red: 2 families,

320

ANNELIDA

Key to the families of Gnathobdellida :

»! Three toothed jaws present .............................. 1. HIBUDINIDAE

o2 Three unarmed muscular ridges present in place of the jaws.

2. HEBPOBDELLIDAE

FAMILY 1. HIKUDINIDAE.

Leeches with 3 toothed jaws; segment contains 5 rings; 5 pairs of
eyes: several genera.

1. HIRUDO L. Elongate, flattened leeches with about 95 annula-
tions; margin of body serrate; crop with about 10 pairs of lateral

pockets; teeth very numerous, over 100 in
number; body contracts and does not roll
up: numerous species.

H. medicinalis L. The medicinal leech.
Body yellowish-brown, 10 to 20 cm. long:
an European animal which has been intro-
duced into some ponds and streams in the
eastern United States; used for blood-
letting.

2. HJEMOPIS Savigny. Body rather thick,
with smooth margins; crop with 1 pair of
caeca but without lateral pockets; teeth few,
about 20; 5 pairs of eyes.

H. marmoratis (Say). The horseleech.
Body 10 cm. long or more, 15 mm. wide,
smooth, and very soft; color variegated,
being blackish or brownish, blotched with
irregular spots: in the mud at the side of
pools and streams and also occasionally
on the land; will occasionally suck blood but usually eats worms,
snails, etc.

H. grandis (Verrill). Body 20 cm. long or more, specimens 45 cm.
having been found; color yellow, mottled with black; the largest
American leech: New England, the Great Lakes, and westward.

3. MACROBDELLA Verrill. Body strongly annulated, broad and flat-
tened, and tapering but little; about 65 teeth on each jaw; male orifice
between segments 26 and 27 and the female orifice between segments
31 and 32: 3 species.

M. decora (Say). Body up to 30 cm. long and 25 mm. wide, brown
or olive green in color, with a median row of about 20 red spots and a
row of black spots near each margin; lower surface reddish: very com-
mon in fresh water, a fierce blood sucker, attacking men, cattle, fish,,
frogs, etc., but also eating other animals,

Fig. 504

Fig. 505

Fig. 504 — Herpobdella punc-
tata (Moore). Fig. 505 — Her-
pobdella fervida (Moore).

MTZOSTOMIDA

321

FAMILY 2. HERPOBDELLIDAE.

Body subcylindrical, elongate with 3 unarmed muscular ridges in
place of jaws; crop without lateral pockets: several genera.

1. HERPOBDELLA Blainville (Nephelis Savigny). Body long and
narrow and with smooth margin; segments contain 5 rings each; genital
orifices separated by 2 or 3 rings: many species; on plants and on the
under side of stones in streams.

H. punctata (Leidy) (Fig. 504). Body up to 10 cm. long and 1 cm.
wide; color brownish-black with 4 longitudinal rows of irregular black
spots ; 3 pairs of eyes : common in streams and pools.

H. (Dina Blanchard) fervida (Verrill) (Fig. 505). Body up to 5
cm. long, variegated pale red in color; 3 or 4 pairs of eyes: abundant
in the Great Lakes region.

CLASS 4. MYZOSTOMIDA.*

These animals are small disc-shaped parasites of crinoids, ophiurans,
and starfishes, on the bodies of which they live either in cysts or free.
The body is oval in outline, much flat-
tened, and externally unsegmented. It
possesses, however, five pairs of para-
podia, each of which is stiffened by
two setae, and four pairs of latero-
ventral sucker-like organs which are
probably sense organs. The edge of
the body is serrate in some species ; in
others ten pairs of short cirri extend
from it. A distinct head is not pres-
ent (Fig. 506).

The body cavity is obliterated by
the growth of a vascular parenchyma
throughout it. The mouth is ventral
in position and near the anterior end
of the body ; it opens into the pharynx,
which forms a proboscis. The intestine is straight and sends out a num-
ber of long branches on each side. The anus is near the hinder end of the
body. Special vascular and respiratory organs are wanting ; nephridia are
present. The nervous system is highly specialized. It consists of two

* See "Verzeichniss der von den U. S. Coast Survey Steamers Hassler und Blake,
von 1867-1879, gesammelten Myzostomideen," by L. von Graff, Bull. Mus. Comp.
Zool., Vol. 11, p. 125, 1883. "The Sexual Phases of Myzostoma," by W. M. Wheeler,
Mitt, aus d. Zool. St. zu Neap., Vol. 12, p. 227, 1896. "New Marine Worms of the
Genus Myzostoma," by J. F. McClendon, Proc. U. S. Nat. Mus., Vol. 32, p. 63, 1907.

Fig. 506 — Diagram of a myzostomid
(von Stummer). 1, mouth ; 2, cirrus ;
3, parapodium ; 4, lateral sense organ ;
5, intestinal branches ; 6, ovary ; 7,
nephridium ; 8, uterus ; 9, stomach ;
10, cloaca ; 11, anus ; 12, male genital
pore.

322 ANNELIDA

oesophageal nerve rings and a large ventral nerve mass which is composed
of about six fused pairs of ganglia and sends off numerous nerves. No
special sense organs are present. The animals are hermaphrodite. The
testes are paired, branched organs which are joined on each side by two
vasa deferentia with a lateral sperm sac; this opens to the outside by a
marginal pore near the middle of the body. Two ovaries are present ; the
ova are collected in a median uterus which communicates with the rectum.

The class includes over 70 species and 2 genera.

MYZOSTOMA F. S. Leuckart. With the characters of the class:
numerous species.

M. glabrum F. S. Leuck. Body nearly circular, 4 mm. long, with 10
pairs minute protuberances; parapodia short; cloaca dorsal: Europe, on
Antedon rosacea, attached to the oral plates.

M. cubanum McClendon. Diameter 1.7 mm.; thickness .08 mm.;
dorsal surface flat, with 10 pairs of short conical cirri; ventral surface
convex; parapodia prominent; suckers absent: West Indies, from
crinoids off Havana.

PHYLUM V.

ARTHROPOD A. (CRUSTACEANS, ARACHNIDS, MYRIAPODS,

AND INSECTS.)

Animals which are externally segmented and have segmented ex-
tremities (Fig. 542, A).

External Structure.— The segmentation of arthropods is heterono-
mous, the somites or body segments being unequal in size, and in most
cases the body is made up of three divisions, the head, the thorax, and
the abdomen. Fusion occurs very frequently between contiguous somites
so that their boundaries are obliterated: the somites of the head are
always thus fused. The appendages or extremities are elongated, seg-
mented projections of the ventral body wall, there being typically a
single pair on each somite except on the terminal one. In many
cases where the segmentation has disappeared secondarily the number
of pairs of appendages gives a clue to the number of somites originally
present.

The appendages are primarily locomotory and sensory organs, but
we find them performing many other functions. The first pair forms
the antennae or feelers, where these are present, and their function is
usually purely sensory. One or more pairs form the jaws, which have
thus a right and left position. The appendages of the middle and hinder
part of the body usually preserve their locomotory function and form
the walking or swimming legs. These, however, often serve also other
purposes, as for respiration and the transportation of eggs or young, or
as spinnerets in spiders, and as stings, anal feelers, and ovipositors
among the insects.

The following scheme taken from Korsehelt & Heider*s Textbook of
Embryology illustrates the homologies of the anterior pairs of appendages
in the principal groups of Arthropoda:

CRUSTACEA

ARACHNIDA

INSECTA

Antennae 1.

Antennae.

Antennae 2.

Mandibles.

Mandibles.

Pedipalps.

Mandibles.

Maxillae 1.

Legs 1.

Maxillae.

Maxillae 2.

Legs 2.

Labium.

Thoracic appendages 1.

Legs 3.

Legs 1.

Thoracic appendages 2.

Legs 4.

Legs 2.

Thoracic appendages 3.

Legs 3.

323

324 ARTHROPODA

The largest group of arthropods, the insects, is distinguished by the
possession of wings, two pairs of which are typically present, arising as
projections from the dorsal wall of the thorax.

The principal organs of special sense are the eyes, the tactile hairs,
and the auditory or balancing organs. The tactile hairs are usually dis-
tributed over the body, but are probably most sensitive on the antennae
and the palps, where they are organs of touch, hearing, taste, or smell.
The eyes are of two kinds, simple and compound. A simple eye or
ocellus is a minute structure formed by a modification of the integu-
ment and consisting of a convex retina and a lens. A compound eye is
a much larger and more complex structure and consists of a large number
of distinct elements called ommatidia. Each of these is a separate light-
perceiving body, and the sum of the images of all the ommatidia of a
compound eye forms the picture the animal sees. This is called mosaic
vision and characterizes crustaceans and insects alone among animals.
A pair of lithocysts, or so-called auditory organs, are present in certain
crustaceans; they are organs of equilibration. A few species of insects
have genuine auditory organs.

The integument of arthropods is composed of a shell-like cuticula
which forms the entire outer surface, and a layer of glandular cells called
the hypodermis which lies beneath the cuticula and secretes it. The
cuticula is rendered tough and thick by the presence of chitin and
sometimes of calcium carbonate and forms a very efficient outer cov-
ering. During the period of growth an arthropod sheds its cuticula
periodically.

Arthropods are often highly colored, some of them being among the
brightest of animals: many are protectively colored and many crustaceans
are transparent, being almost invisible in the water in which they live.
Sexual dimorphism is very common, the males being distinguished from
the females by size, color, or other external markings.

Internal Structure.— The digestive tract extends from the mouth to
the anus and is made up of foregut, midgut, 'and hindgut, which, however,
in all arthropods have undergone a large degree of specialization. Sali-
vary glands are generally present in the terrestrial arthropods but are
absent in the aquatic ones. Other digestive glands are wanting in insects,
but in crustaceans and arachnids a voluminous liver is often present.
The excretory organs or kidneys are present in the form of one or more
pairs of tubular glands.

The circulatory system is not highly specialized. A blood fluid is
always present which circulates among the organs in the extensive body
cavity. In many small crustaceans no heart or other vessels are present,
but the circulation is maintained by the movements of the intestine or of

GENEEAL DESCRIPTION 325

the whole body. In most arthropods, however, a heart, usually tubular
in shape, is present in the dorsal part of the body cavity, the beating of
which keeps the blood in circulation. In no arthropods, however, is there
a closed vascular system, as the blood, even in the highest, passes from the
tissues to the respiratory organs through open spaces of the body cavity. In
most arthropods respiratory organs in the form of projections from the
legs or the sides of the body are present. In the crustaceans these pro-
jections extend into the water and form the gills, while in the air-breathing
forms the projections extend into the body cavity and become the so-called
lungs of the arachnids or the tubular tracheae which carry respiratory
'air directly to the blood. The muscular and nervous systems of arthro-
pods are highly developed. The muscles are all striated and are probably
the most energetic among animals.

The main nervous system, like that of annelids, consists of a number
of pairs of segmentally arranged ganglia and nerves connecting them.
The anterior pair constitutes the brain and is situated in the dorsal
portion of the head; from it nerves go to the eyes and the antennae.
The remaining parts are ventrally situated, one pair being typically
in each somite. In most arthropods, however, fusion has occurred among
the ganglia so there are fewer pairs of them than of somites. This fusion
has gone so far in some of the highest arthropods that all the ventral
ganglia have come to form a single mass. In all arthropods the brain
is distinct and is joined with the ventral ganglia by a pair of connecting
nerves, one of which passes on each side of the oesophagus.

With a few exceptions arthropods are unisexual, the hermaphroditic
forms being a few parasitic or sessile crustaceans and a few arachnids.
The gonads are usually paired, tubular glands which open to the outside
by a pair of openings in crustaceans and by a single median abdominal
opening in most other arthropods. Parthenogenesis occurs among certain
crustaceans and insects, and pasdogenesis occurs as a rare phenomenon
among the latter.

Arthropods are generally characterized by the care they take of their
eggs and young. Many of them carry their eggs until they hatch, and
often the young animals are also carried. Among insects a family life
of remarkable complexity characterizes many species, which often leads
to the formation of colonies characterized by a division of labor among
their individual members, as in the case of the bees, termites, and many
others.

Distribution.— Arthropods constitute the largest phylum of animals,
numbering about 400,000 known species, or four-fifths of all known spe-
cies of animals. They form also one of the most widely distributed
groups, being found in all parts of the sea and land. The crustaceans

326 CRUSTACEA

are almost exclusively aquatic and the arachnids and tracheates almost
exclusively terrestrial and aerial animals.

History.— Linnaeus gave the name Insecta to all the animals which
'are now included under the Arthropoda, the crustaceans, spiders, and
myriapods being Insecta aptera. Cuvier in 1800 created the Crustacea
as an independent class, and Lamarck in 1801 performed the same service
for the Arachnida, restricting the term Insecta to the Hexapoda and the
Myriapoda. The last-named group was created in 1796 by Latreille. All
these animals were joined by Cuvier with the Annelida to form the Ar-
ticulata, but in 1845 von Siebold separated the Annelida from the others,
making a class of them under the Vermes, and formed an independent
group of the Crustacea, Arachnida, and Insecta to which he gave the name
Arthropoda.

The phylum contains 3 classes.

Key to the classes of Arthropoda:

01 Aquatic arthropods (with a few exceptions) having gills and 2 pairs of

antennae 1. CRUSTACEA

02 Air-breathing arthropods (with a few exceptions).

Z>! Antennae absent 2. ARACHNOIDEA

62 One pair of antennae present 3. TRACHEA TA

CLASS 1. CRUSTACEA.*

Aquatic arthropods which breathe by means of gills and have 2 pairs
of antennae and biramose appendages (Fig. 542).

External Structure.— An. elongated body with distinct segmentation,
in which the primary division into head, thorax, and abdomen is evident,
characterizes most crustaceans. A tendency is however present in all the
groups towards a fusion of the somites and a shortening of the body.
Those forming the head are always thus fused and are besides often
joined with some or all of the thoracic somites, forming thus a body
division called the cephalothorax, which in many crustaceans is wholly or
partly covered by a bivalve shield called the carapace.

The appendages are fitted primarily for locomotion and respiration in
the water and are typically biramose, each consisting of a basal piece, the
protopodite, and two segmented, terminal pieces, an outer one, the exopo-
dite (Fig. 516, 16), and an inner one, the endopodite (Fig. 516,17). Although
this is the primitive condition of the appendage, the performance of special
functions has in many cases brought about a modification of it and often a
loss of some of its parts.

* See "Crustacea," by A. Gerstaecker and A. E. Ortmann. Bronn's "Klass. u.
Ord. d. Thierreichs," Bd. 5, Abt. 1 and 11, 1866-1901. "Crustacea," by J. S. Kingsley,
Standard Natural Hist., Vol. 2, 1888. "List of the Crustacea," by Mary J. Rathbun,
Fauna of New England in Occasional Papers of the Boston Soc. of Nat. Hist., VII,
1905.

GENERAL DESCRIPTION 327

Five pairs of appendages are present in the head, the first antennae,
second antennae, mandibles, first maxillae, and second maxillae. Of these,
the first pair of antennae (antennules) differs from all the other append-
ages of the body in not being typically biramose; they are not, however,
necessarily simple, but the distal portion of the appendage is frequently
split into two, three, or more branches, called flagella (Fig. 614,1). The
mandibles are short, stout appendages, fitted for biting, and may bear a
sensory palp which is the modified endopodite, the exopodite being want-
ing. The two pairs of maxillae are usually delicate structures whose
function is probably chiefly sensory.

The number of thoracic appendages varies greatly among crustaceans.
The smallest number of pairs (2) is found among ostracods and the
largest number (60) among the Apodidae. The abdominal appendages
are wanting in the Entomostraca and in the youngest larval forms of
most Malacostraca. In adults of the latter group, however, these are
present on all the abdominal segments except the last one (telson).

The cuticula of crustaceans is shed periodically. In the smaller
species it is very delicate and the animal is often quite transparent. In
the large Malacostraca it contains calcium carbonate as well as chitin and
is very hard and thick : it is such animals which have given the group the
name Crustacea.

Internal Structure (Fig. 623).— The digestive tract is in most crus-
taceans a straight tube going from the ventrally located mouth to the
anus at the hinder end of the body. Tubular livers, often very volumi-
nous, are present in most forms; salivary glands are absent. The ex-
cretory organs consist of a pair of tubular glands, the kidneys, which
open to the outside in the neighborhood of the mouth. The respiratory
organs are lacking in some of the small crustaceans, the outer surface of
the body performing this function. In most of them, however, gills are
present, las projections of the thoracic or abdominal appendages or of
the sides of the body.

With the exception of most of the Cirripedia, which are all either
sessile or parasitic, all crustaceans are unisexual. Among the PJiyllopoda
and Ostracoda parthenogenesis is common. In the lower crustaceans the
animal usually leaves the egg as a nauplius larva, 'a minute animal with
three pairs of appendages, of which the first pair is uniramose and the sec-
ond and third pairs are biramose. With a few exceptions (Peneus, Lucifer)
all the higher crustaceans pass through the nauplius stage while still in
the egg and are born in some later stage of development. Many of them,
as the crayfish, have the form of the adult when born, the entire meta-
morphosis having been completed in the egg.

Habits and Distribution.— The sowbugs, land crabs, and a few other

328 CRUSTACEA

forms live on the land, but all others are aquatic animals. The majority
of these live in the sea, the Phyllopoda being the only order which is
better represented in fresh than in salt water. Crustaceans feed largely
on decaying animal and plant substances. Many are parasitic, especially
among the Copepoda, Cirripedia, and Isopoda. The barnacles are the
only sessile crustaceans.

History. — Crabs and other decapods have been known and used for
food from time immemorial. They were first described by Aristotle who
calls them Malacostraca or soft-shelled animals in contradistinction to the
hard-shelled mollusks. Linnaeus placed them among the Insecta aptera.
The lower crustaceans were seen by the earlier microscopists, but very
little studied or understood until the time of 0. F. Miiller, who in 1785
brought together a large number and called them Entomostraca, or insect-
like crustaceans. Cuvier, Latreille, and Lamarck in the first years of the
new century introduced the term Crustacea to include all crustaceans,
although the term had already been used as a synonym of Malacostraca.
The creation of the various orders of crustaceans is largely due to La-
treille, who introduced the names Branchiopoda, Isopoda, Amphipoda,,
Decopoda, and Phyllopoda. Milne-Edwards formed the order Copepoda,,
and Burmeister introduced the terms Arthrostraca and Thoracostraca.

American crustaceans have attracted many able investigations from-,
the time of Thomas Say in the first quarter of the last century to the pres-
ent time. In 1852 appeared the Crustacea of the Wilkes Expedition, by
James Dwight Dana, which was one of the most important zoological-
works of the day. This and the works of Say, Stimpson, S. I. Smith,,
and others form the groundwork of our present knowledge of American!
forms.

The class contains about 16,000 species, grouped in 2 subclasses.

Key to the subclasses of Crustacea:

at Small, often minute crustaceans without abdominal appendages.

1. ENTOMOSTBHC-A
o2 Larger crustaceans usually with abdominal appendages. . .2. MALACOSTRACA.

SUBCLASS 1. ENTOMOSTRACA.

Small crustaceans, the majority of which are under a centimeter in
length; somites variable in number; head, thorax, and abdomen usually
distinctly marked, but in many the head and one or more thoracic somites
are fused together, forming a cephalothorax ; body either elongate with
distinct segmentation or much shortened and enclosed in a chitinous shell
called the carapace; parasitism has produced great changes. in the form
of many entomostraceans so that all semblance of the crustacean form is
often lost ; appendages confined to the head and the thorax, 5 pairs being

PHYLLOPODA 329

cephalic and the thoracic appendages varying in number from 2 pairs
to 60 : 4 orders with about 4,800 species.
Key to the orders of Entomostraca :

«! Free swimming or parasitic on fish (rarely on other animals).
&i Thoracic appendages flattened and leaf-like ; body either elongate and
segmented or short and more or less covered with a carapace.

1. PHYLLOPODA
6, Body either elongate and segmented with cylindrical thoracic appendages,

or greatly modified when the animals are parasites 2. COPEPODA

fc, Body short and unsegmented and entirely enclosed in a bivalve cara-
pace 3. OSTBACODA

ca Body sessile and enclosed in a calcareous shell (barnacles) or parasitic

on decapods or mollusks 4. CIBBIPEDIA

ORDER 1. PHYLLOPODA.*

Thoracic appendages flat and leaf -like, as the name indicates, being
organs of respiration; body either long and vermiform and composed
of numerous segments or short and compact and unsegmented; carapace
usually present; parthenogenesis common, the usual eggs being relatively
small and thin-shelled and called summer eggs; at the approach of a
period of drought or cold males are born from the parthenogenetic eggs
which fertilize the females, iand the eggs which these then lay are large
and thick-shelled and called resting or winter eggs, and are capable of
enduring the winter's cold or the summer's drought, if need be: 2 sub-
orders and more than 600 species, most of them being fresh-water animals,
living in pools, lakes, and streams containing the minute algae which form
their principal food.

Key to the suborders of Phyllopoda:

aa Body elongated and distinctly segmented 1. BBANCHIOPODA

Oj Body short with indistinct segmentation or without any, and usually with

a bivalved carapace 2. CLADOCEBA

SUBORDER 1. BRANCHIOPODA.f

Elongated phyllopods with numerous distinctly marked segments, and
either with or without a carapace; the young born as nauplii: several
families and over 100 species, which, with a few exceptions, live in fresh
water.

Key to the families of Branchiopoda here described:

at Carapace absent 1. BBANCHIPODIDAE

o2 Carapace present.

6X Carapace flattened dorsoventrally and arched 2. APODIDAE

52 Carapace compressed laterally 3. LIMN ADHD AE

* See "Die Siisswasserfauna Deutschlands," Heft 10, 1909.

t See "Phyllopod Crustacea of North America," by A. S. Packard, 12th Ann. Rep.
U. S. Geol. Sur. of the Ter., 1878 (1883), pt. 11, p. 294.

330 CRUSTACEA

FAMILY 1. BRANCHIPODIDAE.

Body elongate, being composed of many segments and without cara-
pace; head distinctly set off; first antennae filiform; second antennae of
male used for clasping the female, being very large and composed of 2 elon-
gated segments and with or without extra frontal appendages between
them; thoracic segments and appendages mostly 11; abdominal segments
8 or 9 in number; 2 stalked eyes present; a pair of egg sacs extend from
the last thoracic segment of female: 8 genera; the animals live in fresh
and salt pools and swim on their backs.

Key to the genera of Branchipodidae here described:

tti Frontal appendages present.

61 Frontal appendages simple in form 1. BRANCHIPUS

62 Frontal appendages branched 2. CHIBOCEPHALUS

a2 Frontal appendages absent.

&! Abdomen with 8 segments 3. ABTEMIA

62 Abdomen with 9 segments 4. BRANCHINECTA

1. BRANCHIPUS Schaeffer. Beween the second antennae of male
are 2 unbranched frontal appendages; abdomen consisting of 9 segments

Fig. 507 Fig. 508

Fig. 507 — Branchipus vemalis — male (Packard). 1, first antenna; 2, second
antenna ; 3, frontal appendage. Fig. 508 — CTtirocephalus holmani — front view of
head of male (Packard). 1, eye; 2, first antenna; 3, second antenna; 4, frontal
appendage.

and 2 long caudal projections which have setose margins: 2 American
species.

B. vernalis Verrill. The fairy shrimp (Fig. 507). Body semi-
transparent and pinkish in color; length 23 mm.; frontal appendages
broad and flat: eastern North America, in fresh- water pools during the
spring, autumn, and winter, passing the summer as resting eggs; often
common, but sporadic.

2. CHIROCEPHALTJS Prevost. Between the second antennae of male
2 very long, branched, and coiled frontal appendages; abdomen con-
sisting of 9 segments and with 2 long, broad caudal projections with setose
edges: 1 American species.

C. holmani Ryder (Fig. 508). Body slender, 15 mm. long: eastern
North America (Philadelphia, Long Island).

PHTLLOPODA

331

3. ARTEMIA Leach. No frontal appendages present; second joint of
second antennae flat and triangular; abdomen of 8 segments and with 2
very short caudal projections; egg sac short: several

species, all in salt pools and lakes ; 2 American species.

A. gracilis Verrill (Fig. 509). Body semitranspar-
ent, pink or green in color, 10 mm. long: eastern and
central North America, as far west as Great Salt Lake.

A. franciscana Kellogg. Body translucent whitish
or dull brick red in color and slender; length 13 mm.;
caudal appendages with setose edges: California.

4. BRANCHINECTA* Verrill. No frontal append-
ages between second antennae, the second joint of

I which is simple and slender; ab-

domen of 9 segments; egg sac
long and slender: 3 species, in the
western states.

B. coloradensis Packard (Fig. 510). Length 18
mm.; second antennae large, and broad and bent in,
and not serrate: very common in Colorado.

Fig. 509
Artemia gracilia

(Packard).

1, first antenna

2, second antenna

3, ovisacs

Fig. 510

Branchinecta

coloradensis —

front view of head

of male (Shantz).

1, first antenna

2, second antenna

FAMILY 2. APODIDAE.

Body elongate and composed of many segments,
and with an oval, low-arched carapace covering the
head and thorax; eyes sessile; first antennae short and
filiform with 2 or 3 flagella; second
antennae minute or wanting in the

adult; 40 to 60 pairs of broad feet, the first pair end-
ing with 3 long, slender branches, the eleventh pair

forming egg capsules in the female; 2 long caudal

bristles; larva a nauplius: 2 genera; in fresh water.
APUS Schaeffer (Triops Schrank). With the

characters of the family: about 4 American species,

all in the western states.

A. lucasanus Packard (Fig. 511). Telson with

3 central spines ; length, with caudal bristles, 41 mm. :

western America, abundant in Kansas.

Apus lucasanus
(Packard).

FAMILY 3. LIMNADIIDAE.

Body elongate and entirely enclosed in an oval laterally compressed
carapace, which gives the animal the appearance of a bivalve mollusk;

* See "Notes on the North Am. Species of Branchinecta," etc., by H. L. Shantz,
Biol. Bull., Vol. 9, p. 249, 1900.

332

CEUSTACEA

eyes sessile and close together; first antennae minute, second large, with
2 terminal branches; 18 to 28 pairs of broad feet, the first or the first
and second pairs being prehensile in the male : in fresh water, differing
from the Cladocera and Ostracoda in being much larger and in having
distinct segmentation and more appendages and an abdomen which is not
bent under the thorax; about 5 genera.

Key to the genera of Limnadiidae here described :

d Lines of growth on shell ; 24 pairs of feet ...................... 1. CYZICUS

o2 No lines of growth ; 10 to 12 pairs of feet ..................... 2. LIMNETIS

1. CYZICUS Audouin (Esthe-
ria Riippell). Shell oval and
opaque, amber-colored ; body
rather thick; head with a long
narrow rostrum; about 24 pairs
of flat feet, the first two pairs
being prehensile in the male:
numerous species, about 8 in
America, all in the West.

C. morsel (Packard) (Fig.

Fig. 512 — Cyzicus morsel (Packard).

Shell 12 mm. long, 8 mm.

512).
., the two branches of second antennae with

17

Fig. 513— Limnetis
gouldi (Packard).

high, and 6 mm. across

and 16 joints each: widely distributed throughout

the central and western parts of the country.

2. LIMNETIS Loven. Shell oval or spherical, with
no lines of growth ; head with a large rostrum ; 11 or
12 pairs of feet, the first pair being prehensile in the
male; eggs carried in a dorsal brood chamber: 4
species in America.

L. gouldi Baird (Fig. 513). Body rather thick;
second antennae with 16 segments in each branch;
length of shell 3 mm.; breadth 2.5 mm.; color pink; eyes black: eastern
and central Amerjca, westward to the Mississippi.

SUBORDER 2. CLADOCERA.*

Water fleas. Body usually short and compact, without segmenta-
tion, and enclosed in a bivalve carapace; 4 to 6 pairs of thoracic ap-
pendages; first pair of antennae often minute, second pair very large,

* See "Notes on Cladocera," by E. A. Birge, Trans. Wis. Acad., Vol. 4, 1878.
"List of Crustacea Cladocera from Madison, Wis.," by same, ditto, Vol. 8, 1891.
"Notes on Cladocera," by same, ditto, Vol. 9, 1892. "Synopsis of the Ento-
mostraca of Minnesota," etc., by C. L. Herrick and C. H. Turner, Second Rep. of
State Zool., 1895. "The Cladocera of Nebraska," by Charles Fordyce, Stud, from the
Zool. Lab. of the Univ. of Neb., No. 42, 1901.

PHTLLOPODA 333

with the two branches (exopodite and endopodite) prominent, and used
for swimming; abdomen small and usually bent under the thorax; 2
large compound eyes which in many species unite to form a single
median eye; a large dorsal brood sac in the female in which the eggs
develop, the young animals being born with the form of the parent;
the winter eggs are often provided with an extra shell called the ephip-
pium, consisting of 2 chitinous plates, like watch crystals, whose edges
fit together, one, two, or more eggs being in a single ephippium: about
8 families and several hundred species, most of which live in fresh water.
Key to the families of Cladocera here described :

G! Carapace enclosing the entire body.

6j One branch of second antennae with 2 segments, the other with 3.1. SIDIDAE
6a One branch Of second Antennae with 3 segments, the other with 4.

Ci First antennae minute 2. DAPHNIDAE

ca First antennae long and beak-like 3. BOSMINIDAE

63 Both branches of second antenna with 3 segments 4. LYNCEIDAE

Oz Carapace not enclosing the legs and the abdomen.
6j Abdomen curved and rudimentary ; 4 pairs of legs ; fresh and salt

water 5. POLYPHEMIDAE

62 Abdomen straight and very large ; 6 pairs of legs 6. LEPTODOBIDAE

FAMILY 1. SIDIDAE.

Head large and separated from the body by a depression and usually
with a beak; first antennae one-jointed, but long in the male, with a
long terminal flagellum; second antennae very long, the two branches
having 2 and 3 segments respectively; 6 pairs of legs; heart elongate
and intestine straight, without liver sacs: several genera.

Key to the genera of Sididae here described :

#! Dorsal branch of second antennae three-jointed 1. SIDA

aa Dorsal branch of second antennae two-jointed.

6X First joint of second antennae with a long side branch 2. LATONA

68 No such side branch 3. DAPHNELLA

1. SIDA Straus-Diirkheim. Ventral branch of
second antennae with 2 segments; dorsal branch
with 3 segments; beak distinct: several species.

S. crystallina (0. F. Muller) (Fig. 514). Shell
elongate with rounded ends; first antennae in male
long, short in females ; body colorless, sometimes Fig. 514 — Sida crys-

.,, r T -, i , tallina (Siissw. F.

with brown, red, and blue spots; length 2 mm.: in Deut.). i, second an-

i i i n, -11 T j -I tenna ; 2, first anten-

clear lakes; often widely distnbuted; often com- na; 3, abdomen; 4,

mon; Europe.

2. LATONA Straus-Diirkheim. Ventral branch of second antennae
with 3 segments, dorsal branch with 2 segments, the first segment having
a long side branch: 1 species.

334

CRUSTACEA

L. setifera (0. F. Miiller). Body and appendages very setose; color
yellowish, often with spots; length 3 mm.: among weeds in clear lakes;
widely distributed; Europe.

3. DAPHNELLA Baird. Ventral branch of second
antennae with 3 segments; dorsal branch 2 segments;
beak absent ; no teeth on the abdomen ; first antennae
short in female: several species.

D. brachyura (Lievin) (Fig. 515). Length .7 mm.:
in clear water; widely distributed; Europe.

FAMILY 2. DAPHNIDAE.
Body oval; head rounded, usually with a short beak; first antennae
usually minute, consisting of a single segment; the 2 branches of the
second antennae consisting of 3 and 4 segments respectively; 5 pairs of
legs, the last pair separated from that next to it; intestine not coiled
and with a pair of liver sacs : about 12 genera.

Pig. 515

Daphnella

"bracliyura

(Siissw. F. Deut.).

1, second antenna
2, first antenna

Fig. 516 — Daphnia pulex (Kingsley). 1, first antenna ; 2, second antenna ; 3, eye ;
I. optic ganglion; 5, brain; 6, liver sac; 7, intestine; 8, kidney; 9, heart; 10, brood

sac with two eggs ; 11, abdomen ; 12, anus ; 13, ovary ; 14, legs ; 15, mouth ; 16,
exopodite ; 17, endopodite.

Key to the genera of Daphnidae here described :
ox Head terminating ventrally in a beak.
&! Head not separated from body by a dorsal notch; shell with a caudal

spine at the upper posterior angle 1. DAPHNIA

6, Such a notch present.
G! Shell abruptly truncated behind, with a short spine at the lower

posterior angle 2. SCAPHOLEBEBIS

c3 Shell rounded below, with a blunt spine above 3. SIMOCEPHALUS

a2 No beak, or a rudimentary one, present.

&! Abdomen not enclosed by shell 4. MOINA

&a Shell enclosing the whole abdomen 5. CEEIODAPHNIA

1. DAPHNIA 0. F. Miiller. A sharp caudal spine, extending from
the upper posterior angle of shell; head not separated from the body by
a dorsal notch: about 50 species.

D. minnehaha Herrick. Caudal spine less than half the length of
the shell; general form oval, tapexing betindj length 1.8 mm.; a project-

PETLLOPODA

335

ing spur present on the dorsal margin of the head, which in males and
young females has from 1 to 4 sharp teeth: Wisconsin and Minnesota.

D. pulex DeGeer. The common daphnia (Fig. 516). Body oval,
often reddish ; a prominent beak on the under side of the head ; length 2
mm. or more : very common and widely distributed in America and Europe.

D. hyalina Ley dig (Fig. 517). Body oval; caudal spine almost
as long as body; head extended forward in a helmet-like crest but very
variable in shape and size; length 1.8 mm.: widely distributed in this
country and Europe.

2. SCAPHOLEBERIS Schodler. Body short with a truncated hinder
end from the lower margin of which a pair of caudal spines, which are
sometimes very short, extend backwards: 6 species.

Fig. 517 '' Fig. 518 Fig. 519

Fig. 517 — Daphnia hyalina (Herrick). Fig. 518 — Scapholeberis mucronata (Herrick).
Fig. 519 — Simocephalus vetulus (Siissw. F. Deut.).

S. mucronata (0. F. Miiller) (Fig. 518). Spines short; color dark;
length .8 mm. : common in eastern America and in Europe.

3. SIMOCEFHALTJS Schodler. Body obliquely truncate behind, with-
out a caudal spine; abdomen with 2 dorsal processes: 8 species.

S. vetulus (0. F. Miiller) (Fig. 519) . Body large, short, and high ; head
rounded in front, 2.5 mm. long: common in eastern America; Europe.

S. serrulatus (Koch). Head narrow, extending forwards sharply;
length 2 mm.: central United
States; Europe.

4. MOINA Baird. Head with-
out beak; first antennae long; the
end of the abdomen not covered
by the shell; pigment spot (acces-
sory eye) absent: about 10 spe-

Fig. 520 — Moina brachiata, (Herrick).

cies; in muddy swamps, often in
impure water.

M. brachiata (Jurine) (Fig. 520). Body almost as high as long,
greenish in color; 1.3 mm. long: eastern America; Europe.

5. CERIODAPHNIA Dana. No beak present; first antennae short;
head rounded; shell oval or circular, and reticulate: about 20 species;
often in foul water.

0. reticulata (Jurine). Claws of abdomen dentate; length .8 mm.:
eastern and central America; Europe.

336

CRUSTACEA

Fig. 521
Bosmina longirostris

(Herrick).

first antenna ; 2, second
antenna ; 3, egg in
the brood sac.

FAMILY 3. BOSMINIDAE.

First antennae greatly elongated and extending from the beak forms
a long curved proboscis; 5 pairs of feet and rudiments of the sixth;
second antennae small; pigment spot (accessory eye) wanting; intestine
straight and without liver sacs: 1 genus.

BOSMINA Baird. With the characters mentioned above: about 20
species; mostly bottom forms.

B. longirostris (0. F. Miiller) (Fig. 521).
Shell oval with hexagonal markings and with
a caudal spine projecting from the ventral
margin; length .35 mm.: very common in east-
ern and central America; Europe.

FAMILY 4. LYNCEIDAE.
Second antennae small, each branch of
each consisting of 3 segments; pigment spot
(accessory eye) very large; intestine bent or
coiled and usually without liver sacs: the largest cladoceran family,
containing about 20 genera.

Key to the genera of Lynceidae here described :

«! Intestine not coiled or bent 1. EURYCEBCUS

a, Intestine coiled.

Z>! A dorsal keel on head 2. ACBOPEBUS

62 No keel.

c± Body oval or elongate.
di Outer margin of post-abdomen concave in outline ; second antennae

with 7 long setae 3. GBAPTOLEBEBIS

d2 Outer margin of post-abdomen straight.

€i Terminal claw of abdomen with 1 basal spine. . . . 4. ALONA

e2 Two basal spines present 5. PLEUBOXUS

c2 Body globular ; animals minute 6. CHYDOBUS

1. ETTRYCERCUS Baird. Body large and oval with short antennae;
intestine bent like an S and with liver sacs : 1 species.

E. lamellatus (0. F. Miiller) (Fig. 522). Body very large, being
sometimes 3 mm. long; hinder side of the abdomen serrate: central
states; Europe.

2. ACROPERTJS Baird. Body minute, elon-
gate, with a long, broad abdomen; head and
back with a keel; shell with diagonal mark-
ings; intestine coiled: 3 species.

A. harpae Baird (Fig. 523). Body truncate
behind ; length .7 mm. : widely distributed over
eastern and central America ; Europe ; common.

3. GRAPTOLEBERIS Sars. Body minute, elongate; posterior margin
straight; second antennae with 7 long setae: 1 species.

Fig. 522 — Eurycercus lamel-
latus (Siissw. F. Deut.).

PHTLLOPODA

337

G. testudinaria (Fischer) (Fig. 524). Length .7 mm.; shell reticu-
late: eastern and central America; Europe.

4. ALONA Baird. Body minute, more or less oval or rectangular
in form, with small antennae, the second having 8 setae; with a coiled
intestine: numerous species, which are very variable in form.

A. quadrangularis (0. F. Miiller) (Fig. 525). Body oval or quad-
rangular; pigment spot smaller than eye, abdomen very broad and short;

Fig. 523 Fig. 524 Fig. 525

Fig. 523 — Acroperus harpae (Herrick). Fig. 524 — Oraptoleberis testudinaria (Siissw.

F. Deut.). Fig. 525 — Alona quadrangularis (Siissw. F. Deut.).

shell smooth and yellowish in color; length .9 mm.: widely distributed
over eastern and central America; Europe.

5. PLEUROXUS Baird. Front end of head long and pointed, forming
a beak; shell with an arched dorsal edge; intestine coiled: numerous
species.

P. procurvns Birge (Fig. 526). Hinder margin of shell denticulate;
beak curved upwards, forming a hook; length .5 mm.: eastern and
central America.

6. CHYDORUS Leach. Body minute, spherical, with a long curved
beak; antennae short; intestine coiled: 8 species.

2

Fig. 526 Fig. 527 Fig. 528

Fig. 526 — Pleuroxus procurvus (Herrick). Fig. 527 — Chydorus sphericus (Herrick).
Fig. 528 — Polyphemus pediculus (Siissw. F. Deut.). 1, first antenna ;
2, second antenna ; 3, brood sac ; 4, abdomen.

C. sphericus (0. F. Miiller) (Fig. 527). Shell reticulated; pigment
spot almost as large as the eye ; color yellowish ; length .4 mm. : widely
distributed over eastern and central America; Europe.

FAMILY 5. POLYPHEMIDAE.

Carapace not enclosing the legs and abdomen, and serving only as
a brood sac; 4 pairs of legs which lack the flattened respiratory pro-
jections of other Pliyllopoda; abdomen slender, with 2 long caudal
spines; head very large, with a single large eye and large second anten-
nae: 4 genera.

338

CEUSTACEA

Fig. 529 Fig. 530

Fig. 529 — Evadne nordmanni (Sharpe).

A, female ; B, male.
Fig. 530 — Podon leuckarti (Sharpe).

Key to the genera of Polyphemidae here described :

d Fresh-water animals 1. POLYPHEMUS

o2 Marine animals 2. EVADNE

&! Head and thorax continuous dorsally.

62 Head and thorax separated by a notch 3. PODON

1. POLYPHEMUS 0. F. Miiller.
Head separated from thorax by a
dorsal depression: 2 species.

P. pediculus (L.) (Fig. 528).
Length 1 mm.; body highly colored
but transparent : usually in deep lakes
and rivers; a back-swimmer; widely
distributed throughout America and
Europe.

2. EVADNE Loven. Head and
thorax not separated by a dorsal depression; brood sac very high;
antennae small: 3 species; marine.

E. nordmanni Lov. (Fig. 529). Outer branch of third pair of legs
with a single spine; length 1.15 mm. or less; colorless: very common
along the Atlantic coast.

3. PODON Lilljeborg. Head and thorax separated by a dorsal depres-
sion: several species; marine.

P. leuckarti (Sars) (Fig.
530). Length 1 mm.; both
branches of the second an-
tennae with 6 bristles each:
common along the Atlantic
coast occurring with the pre-
ceding; Europe.

FAMILY 6. LEPTODORIDAE.

Shell rudimentary and not covering the
legs or the long, segmented abdomen; 6
pairs of cylindrical legs, the first pair
being much larger than the others; 2 ter-
minal claws on the abdomen: 1 genus.

LEPTODORA Lilljeborg. With the
characters mentioned above: 1 species.

L. hyalina Lillj. (Fig. 531). Body elongate; first antennae small
in female, but very long in male; length 9 mm.; transparent: in clear
fresh-water lakes in America and Europe; it comes to the surface usually
only on dark nights.

Fig. 531 — Leptodora
hyalina. 1, first anten-
na ; 2, second antenna ;
3, shell.

COPEPODA 339

ORDER 2. COPEPODA.*

Body elongated, the thorax and abdomen being usually distinctly
segmented, and made up of 15 somites, 5 of which are united to form the
head and 5 form each the thorax and the abdomen. The head and thorax
together form the cephalothorax. In many forms fusion takes place
between the head and the first thoracic somite, or between the fourth
and the fifth thoracic somites, so that but 4 free thoracic segments are then
present. The abdominal somites are also often united in the female, the
first and second invariably. The last abdominal segment ends with
the furca, a pair of terminal projections bearing a definite number of long
caudal bristles. In the parasitic copepods the form and structure of the
body have often been profoundly changed, and all semblance to the typical
copepod form may have been lost. Ten pairs of appendages are present,
5 of which are cephalic and 5 thoracic. The first pair of antennae
is uniramose and is longer than the second and may be used for locomo-
tion; in the male either one or both of the first pair are often modified
to form clasping organs. The second pair is biramose (but occasionally
uniramose) and sometimes provided with prehensile hooks and spines.
A poisonous sting is present in front of the mouth in Argulus. The
thoracic appendages are biramose swimming legs (Fig. 542,6), which are
without gills. Except in the Pontellidae and the Argulidae a single
median eye is present.

The genital openings are in the first abdominal segment: except in
the Argulidae the female carries her eggs in 1 or 2 gelatinous masses,
the so-called egg sacs, which project from the segment into the water.
The young animal is born as a nauplius.

More than 2,200 species of copepods are known, of which nine-tenths
are marine. About half of these are non-parasitic and form one of the
most important elements in the plankton, because of their enormous
numbers: they are among the most important scavengers of the sea
and form besides the principal food of herrings and many other fishes.
The parasitic copepods are called fish lice and live on the external surface
and gills of fishes and occasionally on squids and other animals. The
order contains about 20 families grouped in 2 suborders.

* See "Die freilebenden Copepoden," etc., by C. Glaus, 1863. "Deutschlands
freilebende Siisswasser Copepoden," by O. Schmeil, Bibliotheca Zoologica, 1892-1896.
"Synopsis of the Entomostraca of Minnesota," etc., by C. L. Herri ck, Sec. Rep. of
State Zool., 1895. "Copepoda of the Woods Hole Region," by W. M. Wheeler, Bull.
U. S. Fish. Com. for 1899, Vol. 19, p. 157. "Freshwater Copepoda of Mass.," by
A. S. Pearse, Am. Nat., Vol. 40, p. 241, 1906. "Notes on Marine Copepoda of R. I.,"
by L. W. Williams, Am. Nat., Vol. 40, p. 639, 1906. "Siisswasserfauna Deutschl.,"
Heft 11, 1909. "Notes on the Marine Copepoda and fladocera of Woods Hole," etc.,
by R. W. Snarpe, Proc. U. S. Nat. Mus., Vol. 38, p. 405, 1911.

340 CRUSTACEA

Key to the suborders of Copepoda:

Oj The female carries egg sacs 1. EUCOPEPODA

«2 No egg sacs present 2. BRANCIIIURA

SUBORDER 1. EUCOPEPODA.

Body elongate; mouth parts biting in the free and sucking in most
of the parasitic forms: 15 families.

Key to the families of Eucopepoda here described:
a± Free-swimming forms (with a few exceptions).

&x First antennae 17 to 25-jointed, being very long, usually as long as the
body ; but 1 egg sac.

cx First antennae prehensile in male ; animals marine 1. CALANIDAE

ca Right first antenna prehensile ; marine and fresh-water animals.

di First pair of legs normal ; but 1 eye present 2. CENTKOPAGIDAE

da First pair of legs weak or rudimentary ; 3 eyes usually present.

3. PONTELLIDAE

62 First antennae not more than 17-jointed ; usually 2 egg sacs.
Cj Abdomen markedly narrower than thorax ; 2 egg sacs ; mostly fresh-
water animals 4. CYCLOPIDAE

c2 Abdomen not markedly narrower than thorax 5. HABPACTICIDAE

a, Parasitic forms, but which may usually be free-swimming at times.
&! Segmentation distinct.
Ci Body with the usual number of segments ; first antennae 5 to 7-jointed.

C2 Segmentation indistinct and irregular. 6* EBGASILIDAE

di Body wide and flat 7. CALIGIDAE

dz Body elongate 8. DICHELESTIIDAE

&2 Segmentation wanting or. indistinct in the egg-bearing female.

<?! Legs rudimentary ; proboscis present ; body worm-like 9. LERN^EIDAE

ca Legs rudimentary or wanting ; no proboscis present ; body worm-
like 10. CHONDRACANTHIDAE

c3 Legs wanting ; proboscis present ; body thick and sac-like.

11. LERN^OPODIDAE

FAMILY 1. CALANIDAE.*
Body elongate; first antennae very long, with
23 to 25 joints, in the male but slightly modified ;
second antennae large and biramose; first 4 pairs
of legs biramose, outer branch 3- jointed ; fifth pair
either like the preceding or modified and unlike
on the two sides; heart present; a single egg sac
present : 26 genera, and over 100 species, all marine.
1- CALANUS Leach. Thorax composed of
either 4 or 5 segments, the last one being some-
times asymmetrical; first antennae 25 jointed in
the female: many species.

C. finmarchicus (Gunnerus). Brit (Fig. 532). Length about 4 mm.;
color yellowish or reddish, but sometimes absent; thorax of 5 segments;
fifth pair of legs biramose ; first antennae as long as the body : New Eng-
* See "Copepoda," by W. Giesbrecht and 0, Schmeil, Das Tierreich, 1898,

COPEPODA 341

land coast, a widely spread, pelagic species, sometimes so abundant that
the sea is colored yellow or red, and of great economic importance
because it forms an important source of food of herring and mackerel,
as well as of the Greenland whale.

C. minor Glaus. Length about 1.8 mm. ; thorax of 4 segments ; fifth
pair of legs biramose;
first antennae not as long
as the body: Gulf stream,
off New England, a wide-
ly spread species.

2. CALOCALANUS
Giesbrecht. Thorax of
female consists of 3 seg-
ments, the first somite
being fused with the

head, and the fourth with

Fig. 533— Calocalanus pavo (Wheeler),
the fifth somite; abdo-
men of female of 2 or 3 segments; abdomen of male of 5 segments;
caudal spines very long and plumose: 3 species.

C. pavo (Dana) (Fig. 533). Abdomen of female of 2 segments;
caudal bristles symmetrical, branched, and spreading; length 1 mm.;
body transparent and reddish : a tropical species which may be found in
the Gulf stream oft' New England.

FAMILY 2. CENTKOPAGIDAE.*

Body elongate; first antennae very long, with 23 to 25 joints in the
female; the right one (sometimes the left) in the male being prehensile;
second antennae large and biramose; heart present; first 4 pairs of legs
biramose, the outer branch being 3-jointed, the inner branch 1 to 3-
jointed; fifth pair of legs biramose, often modified for clasping; a single
egg sac present : about 25 genera and 200 species ; in salt and fresh water.

Key to the genera of Centropagidae here described :
Oi Marine animals.
&! First antennae with 24 segments.

Cj Thorax of 5 segments ; 1. CENTBOPAGES

c2 Thorax of 4 segments 2. TEMOBA

62 First antennae with 23 segments 3. METBIDIA

az Both marine and fresh-water animals.
&! First antennae with 25 segments; fifth feet biramose. .. .4. LIMNOCALANUS

62 First antennae with 24 segments ; fifth feet uniramose 5. EUBYTEMORA

a3 Fresh-water animals ; first antennae with 25 segments.

&! Fifth feet uniramose ; abdomen asymmetrical 6. EPISCHUBA

62 Fifth feet b^ramose ; inner branch of first pair of feet 2-jointed.

7. DlAPTOMUS

* See "The North American Centropagidae," etc., by F. W. Schacht, Bull, of 111.
St Lab., Vol. 5, p. 225, 1898.

342

CRUSTACEA

Fig. 534
Centropages

typicus —

dorsal aspect

of female

(Wheeler).

1. CENTROPAGES Kroyer. Thorax of 5 segments; abdomen of male
of 5, of female of 4 segments; first antennae with 24 segments; the 2
branches of all 5 pairs of legs 3-jointed: 13 species;
marine.

C. typicus Kr. (Fig. 534). Fifth thoracic segment
with 2 lateral projections; first abdominal segment of
female with 4 thorn-like bristles; length 2 mm.; color
reddish or bluish, translucent: coast of New England;
Europe.

2. TEMORA Baird. Furca long and slender; furcal
bristles short; thorax of 4 segments; abdomen of male of
5, of female of 3 segments; first antennae with 24 seg-
ments ; the 2 branches of the 5 pairs of legs 2 to 4-jointed :
5 species; marine.

T. longicornis (0. F. Miiller) /-^
(Fig. 535). Length 1.5 mm.:
Woods Hole; very common, especially in the
winter; Europe.

3. METRIDIA Boeck. Thorax of 4 seg-
ments, abdomen of male with 3 segments; first
antennae with 23 segments; the 2 branches of
the first 4 pairs of legs 3-jointed; of the fifth
pair 2 to 4-jointed in female and 5-jointed in
the male: 10 species; marine.

M. lucens Boeck (M. hibernica Brady and

Robertson) (Fig. 536). Length 2.5 mm.: New

England coast; Europe.

4. LlMNOCALANUS

G. 0. Sars. Thorax of 5 segments ; abdomen in
female with either 3 or 4 segments, in male
with 5; body slender; furca very long; first
antennae 25-jointed; all the legs biramose, both
branches 3-jointed, except the outer branch of
male, which may be 2-jointed: 3 species; in
fresh and salt water.

L. macmrus G. 0. Sars. Right outer
branch of fifth foot in male indistinctly 3-
jointed with a hook-like process on second
segment; length 2 mm.; color hyaline: cosmo-
politan; often common in deep lakes; Europe.

5. EURYTEMORA Giesbrecht. Thorax of 5 segments; abdomen of
male with 5, of female with 3 segments; first antennae about as long as

Fig. 536 — Metridia lu-
cens (Wheeler). A, dor-
sal aspect of male; B,
fifth pair of legs of male ;
C, fifth pair of legs of
female.

8

Fig. 535 — Temora lon-
gicornis (Wheeler). A,
dorsal aspect of female ;
B, fifth pair of legs of fe-
male : C, fifth pair of legs
of male.

COPEPODA

343

the thorax and 24- jointed; fifth feet uniramose: 7 species; in fresh,
brackish, and salt water.

E. hirundoides (Nordquist) (Fig. 537). Last thoracic segment of
female with 2 large projections; length 1.16 mm.; transparent, with yel-
low bands: Gulf of Mexico and its estuaries, abundant;
Boston and Narragansett Bays; Europe.

6. EPISCHURA Forbes. Thorax of 5 segments; abdo-
men 4-jointed in female, in male 5-jointed, asymmetrical
and with prehensile processes on right side; first 4 pairs
of legs biramose, the outer branch 3-jointed, the inner
branch 1-jointed ; fifth pair uniramose, prehensile in male :
3 species; in fresh water.

E. lacustris Forbes. Length 1.7 mm.; second ab-
dominal segment as long as the rest of the abdomen: in
deep lakes; central and western America.

7. DIAPTOMUS* Westwood. Thorax usually of 5 seg-
ments; abdomen of male with 4, female with 3 segments; first antennae
with 25 joints; inner branch of first pair of legs 2-jointed, outer branch
3-jointed; both branches of legs 2 to 4 are 3-jointed; fifth pair irregular
in form, the inner branch being often rudimentary, the outer branch
usually 4-jointed in the female, and 5-jointed in the male: about 80
species, of which 34 are American; in fresh water.

Fig. 537

Eurytemora

hirundoides

(Herrick).

Fig. 538

Fig. 539

Fig. 538 — Diaptomus oregonensis (Pearse). A, dorsal aspect of female; B, fifth
leg of female ; C, fifth leg of male. Fig. 539 — Diaptomus leptopus. A, lateral aspect
of body (Herrick) ; B, fifth leg of female.

D. oregonensis Lilljeborg (Fig. 538). Body small, 1.5 mm. long;
first abdominal segment of female expanded and equal in length to rest

* See "The North Am. Species of Diaptomus," by F. W. Schacht, Bull. 111. St. Lab.,
Vol. 5, p. 97, 1897. "A revision of the North Am. Species of Diaptomus," by C. D.
Marsh, Trans. Wis. Acad. Sci., Vol. 15, p. 381, 1907.

344

CRUSTACEA

of abdomen; cephalothorax widest in the middle: widely distributed and
common over the entire northern part of the country.

D. leptopus Forbes (Fig. 539). First antennae about as long as the
body ; thorax of 4 segments ; length 1.5 mm. ; body transparent, with pur-
ple bands, especially on the terminal portion of the antennae and the
abdomen: common in the central states.

D. sanguineus Forbes. Body bright red and 2 mm. long; last tho-
racic segments with strong lateral spines, and a dorsal hump; first
abdominal segment with strong lateral spines : central and eastern United
States; common; it occurs only in the early spring, in stagnant pools.

D. minutus Lilljeborg. Body small, 1 mm. long, and slender; thorax
of 4 segments ; antepenultimate joint of first antennae with a long slender
process; terminal hook of right fifth feet in male broad: common in the
Great Lakes and widely distributed in northern America; Europe.

FAMILY 3. PONTELLIDAE.

Body elongate, with 4 thoracic segments; first antennae very long,
the right one in the male being prehensile; second antennae large and

Fig. 540

Fig. 541

Fig. 540 — Tortanus setacaudatus (Williams). A, dorsal aspect of female; B,
abdomen. Fig. 541 — Labidocera (estiva (Wheeler). A, dorsal aspect of female;
B, fifth leg of male ; C, right fifth leg of female.

biramose; first pair of legs weak or rudimentary; heart present; median
eye and also often paired eyes present; but 1 egg sac: 10 genera and
over 70 species; marine.

Key to the genera of Pontellidae here described :

G! First antennae 23-jointed 2. LABIDOCEBA

oa First antennae 17-jointed.

&! The 2 branches of the second antennae of equal length 1. TOBTANUS

&, These branches of unequal length 3. ACABTIA

1. TORTANTTS Giesbrecht. First antennae of female 17-jointed ; abdo-
men of female consists of 2 or 3 and of the male of 5 segments; the 2

COPEPODA

345

branches of the second antennae of about the same length ; 1 large dorsal
eye present; fifth pair of legs uniramose: several species.

T. setacaudatus Williams (Fig. 540). Length of female 1.4 mm.;
thorax of 5 segments ; fifth pair of feet 2-jointed in female and 3-jointed
in male : Narragarisett Bay ; common.

2. LABIDOCERA Lubbock. Thorax of 4 segments ; abdomen of female
of 2 or 3, of male of 5 segments ; first antennae of female of 23 segments ;
eyes present, a dorsal pair and a ventral median eye: about 14 species.

L. sestiva Wheeler (Fig. 541). Length 2
mm.; body transparent; last thoracic segment
in male sometimes asymmetrical: Woods Hole;
common.

3. ACARTIA Dana. First antennae of fe-
male 17-jointed, of uniform thickness through-
out; thorax of 4 segments; 1 large dorsal eye
present; abdomen of female of 3 segments;
outer branch of second antennae much shorter
than the inner; 18 species.

A. tonsa Dana. Length 1.3 mm.; body
transparent: Atlantic and Pacific Oceans;
often very common; a widely distributed
species.

FAMILY 4. CYCLOPIDAE.*

13

Fig. 542 — Diagram ol
Cyclops (altered from
Siissw. F. Deut.). 1, first
antenna ; 2, second anten-
na ; 3, mandibles ; 4, first
maxilla; 5, second maxilla
(maxilliped) ; 6, 7, 8, 9,
the first four pairs of tho-
racic legs, each leg being
composed of a basal piece,
the protopodite, and two
terminal pieces, the exopo-
dite and endopodite ; 10, the
fifth pair of thoracic legs;
11, receptaculum seminis,
in the first abdominal seg-

Thorax with 4 free segments, first an-
tennae usually about two-thirds the length of
the body, both being modified in the male to
serve as prehensile organs; second antennae
short and uniramose; first four pairs of feet
biramous, outer branch 3-jointed, inner branch
1 to 3-jointed; fifth pair of feet rudimentary,
alike in both sexes, rudiments of a sixth pair
sometimes present; heart absent; 2 egg sacs
present : about 75 species and 5 genera, mostly
in fresh water.

1. CYCLOPSf 0. F. Miiller (Fig. 542). Thorax with 4 free segments,
abdomen with 5 segments in the male and 4 in the female; first antennae

• See "A Contribution to a Knowledge of North Am. Fresh- Water Cyclopidae," by
E. B. Forbes, Bull. 111. St. Lab., Vol. 5, 1897.

t See "A Revision of the North American Species of Cyclops," by C. D. Marsh,
Trans. Wis. Acad. Sci., Vol. 16, p. 1067, 1909. "The Distribution of the Genus
Cyclops in the Vicinity of Haverford, Pennsylvania," by Reynold A. Spaeth, Proc.
Acad. Nat. Sci., Vol. 66, p. 20, 1914.

ment ;
furca.

12, abdomen ; 1J

346

CRUSTACEA

with not more than 17 and second antennae with 4 segments: over 50
species, about 18 being American, all in fresh water, although some
species occur also in brackish and even in salt water; many species are
extremely variable in form.

Key to the species of Cyclops here described :

«! First antennae 17-jointed.

&! First antennae not reaching the hinder border of head segment.. C. VIBIDIS
&2 First antennae reaching beyond this point.

d Fifth feet with 2 long plumose terminal bristles C. LEUCKABTI

ca Fifth feet with 2 smooth terminal bristles C. BICUSPIDATUS

c3 Fifth feet with 3 terminal bristles C. ALBIDUS

»2 First antennae 12-jointed C. SERBULATUS

03 First antennae 10 or 11-jointed C. PHALEBATUS

C. leuckarti Glaus (C. edax Forbes) (Fig. 543). Body slender and
1.3 mm. long; first abdominal segment very long, equaling the other 3;
first antennae 17-jointed ; fifth feet 2-jointed, the second joint with 2 very

long bristles, the outer one
springing from the middle of
the segment, the first joint also
with a bristle: very common
in the Great Lakes and in all
parts of the country; Europe.
C. viridis Jurine (Fig.
544). Body 1.5 to 5 mm. long
and variable in color, usually
greenish; first antennae 17-jointed and very short, hardly reaching the
hinder border of the head; fifth feet 2-jointed with a very broad basal
joint, each joint bearing a plumose bristle. This species, which occurs also
in Europe, is usually the commonest one in small ponds throughout the
country. It is extremely variable,
the 2 principal varieties being C.
viridis var. brevispinosus Herrick,
which tends to the larger size, and
C. viridis var. americanus Marsh
(C. insectus Forbes), the smaller
and more numerous one.

C. bicuspidatus Glaus (C.
pulchellus Sars; C. forbesi Her-
rick) (Fig. 545). Body slender and 1.3 mm. long; first antennae 17-
jointed; fifth feet 2-jointed, the terminal joint with 2 terminal bristles;
f urea and caudal bristles very long : very common over the entire country,
in lakes and rivers, being one of the commonest pelagic cyclops in the
Great Lakes; Europe.

Fig. 543 — Cyclops leuckarti (Sflssw. F. Deut.).

A, furca and furcal bristles ; B, fifth

foot ; C, receptaculum seminis.

B

Fig. 544 — Cyclops viridis (Siissw. F. Deut.).

A, furca and furcal bristles ; B, fifth

foot ; C, receptaculum seminis.

COPEPODA

347

C. albidus Jurine (C. signatus Herrick) (Fig. 546). Body 1.4 mm.
long, and banded with blue or green; first antennae 17-jointed; fifth feet
2-jointed, the first joint being longer than broad, the second joint with 3
terminal bristles : common throughout the country in clear lakes ; Europe.

Fig. 545 — Cyclops bicuspidatus (Sussw. F. Deut.). A, furca and furcal bristles;
B, fifth foot; C, receptaculum seminis. Fig. 546 — Cyclops albidus (Sussw. F. Deut.).
A, fifth foot ; B, furca and furcal bristles ; C, receptaculum seminis.

C. serrulatus Fischer (Fig. 547). Body 1.4 mm. long, rather opaque;
first antennae 12-jointed; fifth feet 1-jointed and plate-like, with 3
terminal bristles: very common everywhere; Europe.

C. phaleratus Koch (Fig. 548). Body 1.2 mm. long, brown in color
with blue feet; antennae 10 or 11-jointed and very short, not reaching
beyond the middle of the head: not common, but generally distributed
in shallow lakes and stagnant pools; Europe.

Fig. 547 — Cyclops serrulatus (Sussw. F. Deut.). A, fifth foot ; B, furca of male ;
C, receptaculum seminis. Fig. 548 — Cyclops phaleratus (Siissw. F. Deut.). A, fifth
foot ; B, receptaculum seminis ; C, furca and furcal bristles.

2. OITHONA Baird. Head terminating with a beak-like process;
abdomen with 4 or 5 segments; first antennae in part indistinctly jointed
and with very long bristles; second antennae 2-jointed: marine.

0. similis Claus. Beak bent down at right angles to head; caudal
setae not plumose; body .75 mm. long and usually colorless: Woods
Hole; Narragansett Bay; Europe.

FAMILY 5. HAKPACTICTDAE.

Minute, elongate copepods with a cylindrical body, the thoracic seg-
ments not being much larger than the abdominal; first antennae short, 4

348 CEUSTACEA

to 10-jointed, in the male modified and prehensile ; second antennae usually
biramose; fifth pair of feet 1 or 2-jointed and serving as egg support in
the female; heart absent; usually a single egg sac present: about 30
genera and 150 species, mostly marine, usually found among vegetation.
Key to the genera of Harpacticidae here described :

0,1 Fresh-water animals ................................ 1. CANTHOCAMPTUS

O2 Marine animals.

&! The outer branch of the first pair of legs much longer than the inner.

2. HARPACTICUS

62 The inner branch longer than the outer ................... 3. ECTINOSOMA

1. CANTHOCAMPTTTS Westwood (Fig. 549). Thorax of 4 segments;
head with a rostrum; first antennae with 6 to 9 joints, usually 8 in the
female; abdomen 5-jointed in the male and 4 in the
female: mostly in fresh water; about 6 American species.

C. minutus Glaus. Body 1 mm. long; first antennae
8-jointed; legs 3-jointed in both branches, except the
fifth leg, which is 2-jointed: eastern and central states;
common, especially in muddy pools; Europe.

2. HARPACTICUS Milne-Edwards. Outer branch of
the first leg 3-jointed, almost twice as long as the 2-jointed
inner branch; conical rostrum present; third pair of legs
with very strong outer branch: 12 species; marine.

H. chelifer (0. F. Miiller). Length of male 1 mm.;
first pair of legs with 1 spine, outer branch with 3; inner
caudal spines longer than the cephalothorax : Atlantic

cactus C0ast; Eur°Pe'

F.St). 3* ECTINOSOMA Boeck. First antennae 5 to 7-jointed;

first pair of legs scarcely smaller than the others and with
the inner branch longer than the outer; fifth pair of legs 2-jointed: 12
species.

E. curticorne Boeck. Length .7 mm.; color dark brown; first an-
tennae very short, 6-jointed: common in Narragansett Bay; Europe.

4. PARATEGASTES G. 0. Sars. First antennae 6 or 7-jointed; second
antennae with a 1-jointed outer branch; last pair of legs very large in
the female, with an expansion on the basal joint.

P. sphaericus Glaus. Length .35 mm.; color brown: abundant in
Narragansett Bay; Europe.

FAMILY 6. EEGASILIDAE.*

Body more or less cylindrical, somewhat like Cyclops in shape,
usually well segmented ; first pair of antennae 5 to 7-jointed, second 3 or

* ''North American Parasitic Copepods Belonging to the Family Ergasilidae," by
C. B. Wilson, Proc. U. S. Nat. Mus., Vol. 39, p. 263, 1911.

COPEPO-DA

349

4-jointed and modified to form a pair of large hooks for prehensile pur-
poses; female carries a pair of long egg sacs and is parasitic, usually on
the gills of fresh- water fishes: about 10 ge-
nera and 85 species; about 15 species known
in America.

ERGASILUS von Nordmann. Cephalo-
thorax pear-shaped, fifth pair of legs rudi-
mentary: several species.

E. versicolor C. B. Wilson (Fig. 550).
Length 1.5 mm. : parasitic on the gills of the
common bullhead and three kinds of catfish.

FAMILY 7. CALIGIDAE.*

Body wide and flat, the segmentation
being more or less obliterated and the female
being larger than the male; first antennae
short, with 2 to 3 joints; second antennae in
form of short hooks; mouth parts form a
suctorial beak; first 4 pairs of legs usually
biramose and facilitate rapid swimming;

fifth pair reduced or

wanting; 2 long egg

sacs with the eggs in a single row in each : about

35 genera and 200 species, which are parasitic

externally on fishes.

Key to the genera of Caligidae here described :

(ii A pair of suckers at front end of body. .1. CALIGUS
o2 No suckers present 2. LEPEOPHTHEIEUS

1. CALIGTJS 0. F. Miiller. First and fourth
pairs of legs uniramose, second and third bira-
mose ; body composed of 4 parts, a cephalothorax,
a thorax, a genital segment, and an abdomen; a
pair of suckers at the base of the first antennae :
17 American species.

C. rapax Milne-Edwards (Fig. 551). Free
thoracic segment small and narrower than the
genital segment, which in the female is about
twice as wide as the abdomen; length of female
about 6 mm.: the commonest species, occur-

Fig. 550 — Ergasilus versi-
color (Wilson).

Fig. 551 — C aligns rapax

(Wilson). 1, sucker;

2, egg sac.

* See "North Am. Parasitic Copepods Belonging to the Family Caligidae," etc., by
C. B. Wilson, Proc. U. S. Nat. Mus., Vol. 28, p. 479, 1905 ; Vol. 31? p. 669, 1907 ; Vol,
33, p. 323, 1908,

350

CRUSTACEA

Fig. 552

Lepeophthei-

rus edwardsi

(Wilson).

ring on the cod, flounder, and more than 25 other kinds of marine
fishes.

2. LEPEOPHTHEIRUS von Nordmann. Similar to Caligus but with
out the suckers: 12 American species.

L. edwardsi C. B. Wilson (Fig. 552). End segment
less than half as long as the genital segment and
1-jointed; length of female about 7 mm.: on flounders
and other fish.

FAMILY 8. DICHELESTIIDAE.

Body usually elongated and flattened, with segmen-
tation partially obliterated; first antennae delicate and
usually many-jointed; second antennae in form of long
hooks; hinder pair of legs usually reduced: about 20
genera and 60 species, which are parasitic on fishes,
principally selachians.

DICHELESTIUM Hermann. First 2 pairs of legs
small and biramose, third pair broad and plate-like,
fourth and fifth wanting; first antennae 8- join ted: 3 spe-
cies, in fresh and salt water.

D. sturionis Herm. Length 2 cm.: on the gills of sturgeons; Vine-
yard and Long Island Sounds.

FAMILY 9. LEKNJEIDAE.

Body very different in form at different periods ; during the breeding
period the animals swim about freely, and the body consists of a large
cephalothorax, a thorax bearing 4 pairs of biramose legs, and an elongate
abdomen; after fertilization the female changes into an unsegmented,
worm-like creature with minute legs and projections at the forward end
representing the antennae, and with a pair of egg sacs projecting from
the hinder end; the front end is imbedded in the body of the fish on
which it lives: about 50 species.

1. LERNJEA L. The pairs of legs of the swimming individuals close
together; body of egg-bearing female twisted S-shape, with a pair of
egg sacs.

L. branchialis L. Length extended, 4 cm.; egg sacs convoluted: on
the gills of the cod and other fishes.

2. LERNE.2ENICUS Lesson. Legs of the swimming forms much re-
duced and close together; body of adult female elongated, with long
egg sacs.

L. radiata Les. (Fig. 553). Length 4 cm.: on the menhaden;
common.

COPEPODA

351

FAMILY 10. CHONDRACANTHIDAE.

Female without segmentation and with paired blunt projections rep-
resenting the appendages, with long egg sacs; male very small, seg-
mented, with 2 pairs of legs, and attach themselves to the body of the
female: about 40 species.

CHONDRACANTHITS Delaroche. Second an-
tennae form short, stout hooks: about 20 species,
parasitic on the gills of marine fish.

0. cornutus (0. F. Miiller) (Fig. 554). Body
of female elongate, 6 mm. long; length of male
.3 mm. : on the gills of the Pleuronectidae.

FAMILY 11. LEEN^OPODIDAE.*

Fig. 553

Fig. 554

Fig. 553
radiata (
554 — Chondracanthus

Lernecenicus
Verrill). Fig.

'data
[ —
cornutus (Bronn).

Body consists of a head and a thorax; an-
tennae small; first two pairs of legs long and
forming the organs of attachment; other legs
wanting; male minute and attached to the body
of the female; female with 2 thick egg sacs:
about 60 species.

LERKEOPODA Blainville. Head somewhat smaller than the thorax,
which is slender and not segmented : about 9 species ; in fresh and salt water.

L. f ontinalis S. I. Smith. Length of female 4 nun. : on brook trout
in Maine.

SUBORDER 2. BRANCHIUEA.

Parasitic copepods with a flattened body consisting of a disc-like
cephalothorax, on the dorsal surface of which is a pair of large com-
pound eyes, with a thorax of 3 free segments, and an unsegmented,
2-lobed abdomen; antennae small; mouth parts consisting of a pro-
boscis containing 2 serrate mandibles and 1 pair of slender maxillae; in
front of the mouth is usually a poisonous sting projecting from a sheath,
into which it can be withdrawn; a large sucker usually present on each
side of the proboscis and just behind it a pair of short uniramose append-
ages, the suckers and the appendages representing the 2 branches of the
second maxillae; 4 pairs of large biramose legs; no egg sacs, the eggs
being deposited on stones and other objects; the animals leave their
hosts occasionally and swim about freely : 1 family and about 37 species.

FAMILY AEGULIDAE.f
With the characters of the suborder: 1 American genus.

* See "North Am. Parasitic Copepods of the Family Lernseopodidae," etc., by
C. B. Wilson, Proc. U. S. Nat. Mus., Vol. 47, p. 565, 1915.

t See "North Am. Parasitic Copepods of the Family Argulidae," etc., by C. B.
Wilson, Proc. U. S. Nat. Mus., Vol. 25, p. 635, 1903.

352

CRUSTACEA

ARGTILUS 0. F. Miiller. Suckers and sting present: 27 species,
parasites on marine and fresh-water fish, usually in the branchial cavity;
13 American species.

A. laticauda S. I. Smith. Carapace elliptical, considerably longer
than wide and not reaching the abdomen, which is broadly elliptical;
length 6 mm. : on the eel, flounder, and other marine fishes ; common.

A. catostomi Dana & Herrick. Carapace round, wider than long,
and reaching the abdomen, which is round and wider than long; length
12 mm.; color light green: on fresh-water fish, especially the sucker
(New England).

A. funduli Kroyer. Carapace wider than long and not reaching the
abdomen, which is very long, being 3 times as long as wide; length 5
mm. : on Fundulus along the Atlantic coast.

A. versicolor C. B. Wilson (Fig. 555). Length 6 mm.; width 4.9
mm.; color brilliantly variegated: in gill cavity of pickerel.

ORDER 3. OSTRACODA.*

Body without segmentation and laterally compressed, and entirely
enclosed in a bivalved carapace. The two sides of the carapace can

be closed by a retractor muscle; when
they open, the appendages are thrust out
and propel the animal through the water.
Seven pairs of appendages are present
(Fig. 556, B). The two pairs of antennae
are used for both locomotion and orienta-
tion, the second pair being either biramose
or uniramose. The mandibles have each a
large 3 or 4-jointed palp; two pairs of
maxillae are present, of which the second
pair are usually leg-like. Two pairs of
legs follow, the second pair sometimes
being bent back and apparently of use

only in keeping dirt out of the shell. The abdomen is short and may end
in a projection with two terminal claws called the furca. The internal

* "A Monograph of the Marine and Freshwater Ostracoda," by G. S. Brady, and
A. M. Norman, Trans. Royal Dublin Soc. Vols. 4 and 5, 1889 and 1896. "Synopsis of
Freshwater Ostracoda," by C. H. Turner, Am. Nat., Vol. 33, p. 877, 1899. "Rep. on
the Freshwater Ostracoda of the TJ. S.," etc., by R. W. Sharpe, Proc. U. S. Nat. Mus.,
Vol. 26, p. 969, 1903. "Marine Ostracoda of Vineyard Sound and Adjacent Waters,"
by J. A. Cushman, Proc. Bost. Soc. Nat. Hist., Vol. 32, p. 359, 1906. "The Ostracoda
of the San Diego Region, II, Littoral Forms," by C. Juday, Univ. Cal. Pub., Vol. 3, p.
135, 1907. "Die Siisswasserfauna Deutschlands," Heft 11, 1911. "Ostracoda," by
G. W. Miiller, Das Tierreich, 1912.

Fig. 555 — Arfjulus versicolor
(Wilson).

OSTRACODA 353

organs are distinguished by their compactness. A heart is usually absent.
A single median eye or a pair of eyes close together is usually present,
but the Cypridinidae have an additional pair of large compound eyes.
Ostracods are unisexual animals, most of which lay eggs which they either
attach to water plants, as in the case of Cypris, or, as in Cypridina, carry
between the shells until they hatch. Cypris and certain other genera are par-
thenogenetic, in certain species no males having yet been discovered. The
Cypridae and Cytheridae are born as nauplii, in which the bivalved shell
is already present; the other ostracods are born later than the nauplius
stage. The Ostracoda live on or near the bottom of both salt and fresh
water, where they crawl or swim actively about and feed principally on
small animals. Entocythere is parasitic on the crayfish. The order con-
tains 2 suborders and more than 1,400 species, of which the great majority
are marine, the Cypridae being the only family which lives almost exclu-
sively in fresh water.

Key to the suborders of Ostracoda:

«! Second antennae apparently uniramose 1. PODOCOPA

a. Second antennae biramose, one branch large, the other minute ; marine.

2. MYODOCOPA

SUBORDER 1. PODOCOPA.*

Second antennae apparently uniramose and bearing sharp bristles,
which are of use in swimming or walking; heart absent; shell without
antennal sinus: 2 families; mostly in fresh water.

Key to the families of Podocopa:

(L! The 2 pairs of thoracic feet dissimilar, second pair bent back 1. CYPRIDAE

c2 The 2 pairs of thoracic feet and the second maxillae all locomotory and

similar 2. CYTHERIDAE

FAMILY 1. CYPEIDAE.

Shell thin ; first antennae 8-jointed, but appearing 6 or 7-jointed, and
with long bristles; second antennae apparently uniramose, the exopodite
being a minute plate with 3 bristles, and leg-shaped and 3 to 6-jointed,
with several long natatory bristles on the second and also the last
joint; usually a single eye present; manibular palp 4-jointed; first max-
illa with a 2-jointed palp; second maxilla small, with a short palp, which
is prehensile in the male; first pair of legs locomotory, the second bent
back and not locomotory; abdomen with a furca; genital organs large,
extending into the space between the shells: about 350 species, mostly
in fresh water.

* See "Contributions," etc., by R. W. Sharpe, Bull. 111. St. Lab., Vol. 4, 1897.

354

CRUSTACEA

Key to the genera of Cypridae here described:
ox Second antennae with natatory bristles.
&! Animals in fresh water.
Cj Second foot terminates with 1 long straight and 1 short curved bristle.

d1 Caudal furca long, each side with 2 terminal bristles 1. CYPRIS

d2 Caudal furca rudimentary 2. CYPRIDOPSIS

c2 Second foot terminates with 2 straight bristles 3. CYPRIA

63 Animals marine 5. PONTOCYPBIS

aa Second antennae without natatory bristles ; animals cannot swim.

4. CANDONA

1. CYPRIS 0. F. Miiller. Eye single, median; second antennae
5-jointed, the 5 natatory bristles extending to the tip of the terminal

8

B

Fig. 556 — Cypris virens (Siissw. F. Deut.). A, left shell; B, diagram showing
organs. 1, eye; 2, first antenna; 3, second antenna; 4, mandible; 5, first maxilla;
6, second maxilla ; 7, first leg ; 8, second leg ; 9, liver ; 10, abdomen ; 11, ovary ; 12,
anus ; 13, intestine.

bristles; first maxilla with a large and second maxilla with a small
branchial plate; parthenogenetic, the males being unknown: about S
American species.

C. virens (Jurine) (Fig. 556). Length 1.69 mm.; height .95 mm.;
breadth .9 mm. ; shell highest just back of the eye and covered with short

Fig. 557

Fig. 558

Fig. 559

Fig. 557 — Cypris fuscata (Stissw. F. Deut.). Fig. 558 — Cypridopsis vidua (Siissw. F.
Deut.). Fig. 559 — Cypria exculpta (Sharpe).

hairs; dorsal side bluish-black; lateral sides greenish with yellowish
areas extending diagonally downwards from the region of the eye : cosmo-
politan.

C. fuscata Jurine (Fig. 557). Length 1.5 mm.; height .9 mm.;
breadth .7 mm. ; shell renif orm and greenish-brown in color with pellucid
spots and a bluish-black patch on either side: cosmopolitan.

OSTEACODA 355

2. CYPRIDOPSIS Brady. Eye single, median; second antennae
5-jointed, the natatory bristles extending beyond the terminal bristles;
caudal furca rudimentary; males unknown: 11 species, 3 American.

C. vidua 0. F. Miiller (Fig. 558). Length .6 mm.; height .34 mm.;
width .4 mm. ; color yellowish-green with 3 transverse bands on the back
and sides: common everywhere in fresh water; a scavenger.

3. CYPRIA Zenker. Body compressed; eye single, median; second
antennae 5-jointed, the 5 natatory bristles very long, extending far
beyond the terminal bristles; furca normal, stout: 11 species, 7
American.

C. exsculpta Fischer (Fig. 559). Length .58 mm.; height .38 mm.;
width .26 mm.; shell thin, somewhat transparent and covered with a
meshwork of longitudinal lines; furca bent: common in shallow ponds
and slowly flowing, shallow streams; Europe.

4. CANDONA Baird. Second antennae of female
5-jointed and lacking the natatory bristles; furca
strong: on the bottom, in the mud and sand, not

being able to swim ; 25 species, 9 American. Fig.

C. acuminata Fischer (Fig. 560). Length 1 mm.; c$££l?.
height .44 mm.; width .36 mm.; shell pointed
behind, white or brown in color; the shorter bristle of the last seg-
ment of second foot 3 or 4 times as long as the last segment: often
common; Europe.

5. PONTOCYFRIS Sars. First antennae 7-jointed
with bristles longest on the last joint and decreasing
in length proximally; second antennae with 4 slender

Fig. sei ponto- claws on last joint and a group of 5 bristles on the

cypris edwardsi T,- -,

(Cushman). antepenultimate: several species; marine.

P. edwardsi Cushman (Fig. 561). Shell somewhat

triangular with rounded ends, hirsute; first antennae with 4 bristles from
basal joint; length .85 mm.; height .47 mm.: Eel Pond, Woods Hole, in
August.

FAMILY 2. CYTHEEIDAE.

Shell usually calcareous and hard ; eyes paired but more or less con-
fluent, sometimes wanting; first antennae 5 to 7-jointed, with bristles;
second antennae leg-like, 4 or 5-jointed, with 2 terminal claws; with a
basal segment bearing a long flagellum which contains a duct from a
poison gland; mandible with palp; first maxilla normal, second maxilla
leg-like and similar to the 2 pairs of legs; furca rudimentary; animals
cannot swim: about 700 species and 30 genera, almost exclusively in
salt water; 8 American marine and 2 fresh-water genera.

356 CRUSTACEA

Key to the genera of Cytheridae here described :

«! Animals marine.

&! Dorsal and ventral margins of shell not parallel 1. LOXOCONCHA

52 Margins of shell nearly parallel.

ct Surface of shell rough 2. CYTHEBEIS

c2 Surface of shell smooth 3. PSEUDOCYTHERETTA

o2 Fresh-water animals.

6X Animals free-swimming 4. LIMNICYTHEBE

63 Animals parasitic 5. ENTOCYTHERE

1. LOXOCONCHA Sars. Shell with a notch at the dorso-posterior
angle; ends and ventral margin extended into a flattened rim; first
antennae 6-jointed, with a group of slender setae on the last joint; sec-
ond antennae 4-jointed: 2 American species; marine.

L. impressa (Baird) (Fig. 562). Length .82 mm.; height .51 mm.:
Vineyard Sound; very common in shallow water, among eel grass,
hydroids, etc.

2. CYTHEREIS Sars. Shell strongly calcareous; first antennae 5 or
6-jointed; second antennae 4-jointed, with a short flagellum in the female;
first pair of feet differing on the two sides of the body in the male : 10
American species; marine.

C. arenicola Cushman (Fig. 563). Shell quadrangular, the dorsal
and ventral margins being almost parallel, 1 mm. long ; .5 mm. high ; sur-
face with irregular patches, usually each with a single hair : common on
sandy bottoms in Vineyard Sound.

Pig. 562 Fig. 563 Fig. 564

Fig. 562 — Loxoconcha impressa (Cushman). Fig. 563 — Cythereis arenicola (Cush-
man). Fig. 564 — Fseudocytheretta edwardsi (Cushman).

3. PSEUDOCYTHERETTA Cushman. Inner border of shell irregular;
flagellum of second antennae 3-jointed; first foot of male with a seta on
the hinder border; left and right first feet of male very different: 1
species.

P. edwardsi Cushman (Fig. 564). Dorsal and ventral margins of
shell nearly parallel, with rounded hairy ends; length 1.2 mm.; width
.61 mm. : Vineyard Sound in rather deep water, the commonest ostracod
of the region.

4. LIMNICYTHERE Brady. First antennae 5-jointed with short bris-
tles on the outer edge; second antennae 4-jointed; mandible with large
branchial plate: 2 American species, both in Illinois.

OSTEACODA

357

L. reticulata Sharpe (Fig. 565). Length .68 mm.; height .35 mm.;
breadth .25 mm.; color whitish; shell with conspicuous polygonal
markings.

5, ENTOCYTHERE* Marshall. First antennae
6-jointed, with long jointed bristles; second
antennae 4-jointed ; mandible with branchial plate :
1 species.

E. cambaria Marsh. Body oval, .6 mm. long;
shell thin and smooth: parasitic on gills of
Cambarus in Wisconsin.

SUBORDER 2. MYODOCOPA.

Fig. 565 — Limnicy there

reticulata — inside

of left shell

(Sharpe).

Second antennae biramose, one branch being large and many-jointed
and usually with natatory bristles, the other minute; front margin of
shell with a deep notch in front for the protrusion of the second an-
tennae: 5 families, marine.

Key to the families of Myodocopa here described :

01 Eyes present 1. CYPRIDINIDAE

02 Eyes absent ' 2. HALOCYPRIDAE

FAMILY 1. CYPRIDINIDAE.

Shell with a deep notch in front (antennal sinus); 3 eyes present;
first antennae stout, 5 to 8-jointed, bearing the large sense organ; second
antennae with outer branch usually 9-jointed; inner branch in male
3-jointed; mandibular foot 5-jointed, terminating in
a claw: 2 American genera.

SARSIELLA Norman. Shell of female without
notch; first antennae 5-jointed, with sense organ on
third joint in male: 2 American species.

S. zostericola Cushman (Fig. 566). Shell 1.3
mm. long and .86 mm. high in the male and 1.1 mm.
long and 1 mm. high in the female, obliquely truncate
behind : on eel grass and hydroids at Woods Hole.

Fig. 566
Sarsiella zostericola

(Cushman).
1, antennal sinus.

FAMILY 2. HALOCYPEIDAE.f

Shell very thin and flexible with notch (antennal sinus) in front,
above which is a rostrum ; median tentacles present between first antennae ;
eyes absent: 3 American genera, all on the Pacific coast.

1. HALOCYFRIS Dana. Rostrum very short, notch small; shell short
and high: 1 American species.

* See "Entocythere cambaria, a Parasite Ostracod," by W. S. Marshall, Trans.
Wis. Acad. Sci., Vol. 14, pt. 1, p. 117.

t See "Ostracoda of the San Diego Region, I. Halocypridae," by C. Juday, Univ.
Cal. Pub., Vol. 3, p. 13, 1906.

358 CRUSTACEA

H. pelagica Glaus (Fig. 567). Shell 1.4 mm. long and 1.1 mm.
high; first antennae strongly curved: Atlantic and Pacific Oceans.

2. CoNCHffiCiA Dana. Shell elon-
gate with well-developed rostrum and
notch: 7 American species.

C. magna Claus. Shell subquad-
rangular, higher behind than in front,
2.6 mm. long and half as high; dorsal
margin with a depression near the mid-
dle: widely distributed in the Atlantic
Fig. 567 — Holocypris pelagica •, T> -fi ^

(Juday). 1, antennal sinus, and Pacific Oceans.

ORDER 4. CIRRIPEDIA.*

Body usually of large size and enclosed in a calcareous shell; animals
marine and sessile as adults, living either attached to rocks, timbers, or
seaweed, or as parasites on or in the bodies of crabs, mollusks, or other
marine animals. A cement gland in the penultimate joint of each anterior
antenna furnishes a secretion by means of which the barnacles are attached ;
the parasitic Rhizocephala fasten themselves to their hosts by means of
long root-like projections of the head. The body, like that of the
Ostracoda, is entirely enclosed in a carapace which arises on the back of
the head and thorax and falls in a right and left fold over the body, form-
ing the characteristic shell. The appendages are a pair of mandibles, two
pairs of maxillae, and six pairs of biramose and plumose thoracic append-
ages or legs. It is these legs which project from the shell and give the
animal its characteristic appearance. In some of the parasitic cirripeds the
number of pairs of thoracic legs is less than 6 and in the Rhizocephala
both they and the mouth parts are altogether wanting. The abdomen is
rudimentary. The digestive tract in the barnacles passes straight to the
anus at the hinder end of the abdomen; in the Rhizocephala no digestive
tract is present, the nutriment being absorbed through root-like projections
of the stalk which entwine the viscera of the crab on which the parasite
is living.

With a few exceptions all cirripeds are hermaphroditic, a condition
which is undoubtedly correlated with their sessile habit of life. In a
few genera of barnacles (Ibla, Scalpellum) complementary males also
occur, which live in or near the genital openings of the hermaphroditic
individuals. Scalpellum ornatum, Ibla cummin gi, and all the species of
the genera Cryptophialus and Alcippe, which burrow in the shell of

* See "A Monograph of the Subclass Cirripedia," by Charles Darwin, 1851-1854.
"The Barnacles (Cirripedia) Contained in the Collections of the U. S. National
Museum," by H. A. Pilsbry, Bull. 60, U. S. Nat. Mus., 1907.

CIRRIPEDIA 359

snails, 'are unisexual, the male being a minute animal, consisting of little
but genital organs, which lives a parasitic life on the body of the female.
Cirripeds are born as nauplii and pass through a later larval stage pos-
sessing a bivalve shell, a pair of compound and a simple eye, called the
cypris stage, during which they attach themselves.

History. — The thick, calcareous shells of barnacles have always made
them conspicuous objects, and they have been well-known animals for a
very long time. The medieval zoologists supposed the Lepadidae to be
the young of bernicle geese, which often appear in large flocks along
the seashore of Europe, and this belief led them to call the animals goose
barnacles. It was not until the beginning of the eighteenth century
that this belief disappeared. The cirripeds were usually classified with
the mollusks by the earlier zoologists, although Lamarck in 1802 placed
them among the crustaceans, until J. V. Thompson in 1830 showed the
barnacle larva to be a nauplius and thus definitely proved their crus-
tacean nature. Cuvier, however, in 1830 still placed them among the
mollusks.

About 500 species of Cirripedia are known, of which about 15 species
occur on our Atlantic coast. The order contains 5 suborders.

Key to the suborders of Cirripedia here described :

Ox Body enclosed in a calcareous shell ; barnacles 1. THOBACICA

c2 Body without a calcareous shell ; animals parasitic.

Z>! Thoracic appendages present ; animals bore into the shells of mollusks

and cirripeds 2. ABDOMINALIA

62 Thoracic appendages wanting ; parasitic on decapods .... 3. RHIZOCEPHALA

SUBORDER 1. THORACICA.

Barnacles. Body enclosed in a calcareous shell and attached at the
dorsal side of the head, the 6 pairs of biramose, tendril-like thoracic legs
being thrust out as the shell opens to gather in the small animals and
organic fragments which form the food: about 4 families.

Key to the families of Thoracica:

Ox Body attached by a long, thick stalk.
Z>! Stalk almost or quite as wide as the rest of the body, and scaly.

1. MlTELLIDAE

62 Stalk much narrower than body 2. LEPADIDAE

o2 No stalk present.

6X On rocks, timbers, etc 3. BALANIDAE

Z>2 On whales 4. CORONULIDAE

FAMILY 1. MlTELLIDAE.

Stalk with scales or spines and as wide as the rest of the body, or
nearly so; shell consists of a large number (18 or more) of pieces;
mostly hermaphroditic, Scalpellum ornatum on the South African coast

360

CRUSTACEA

Fig. 568 — Diagram
of Mitella (Pilsbry).
Explanations as in
Fig. 570.

and Ibla cummin gi in the Philippines, however, being unisexual with com-
plementary males, and Scalpellum vulgare of the European seas hermaph-
rodite also with complementary males; Lithotrya
bores into rocks and mollusk shells and coral:
about 10 species.

1. MITELLA Oken (Pollicipes Leach) (Fig. 568).
Shell consists of from 18 to over 100 pieces, of which
the carina, the terga, and the scuta are the largest;
hermaphroditic: 8 species.

M. polymerus (Sowerby). Shell composed of
upwards of 180 pieces arranged in several whorls,
decreasing in size from above downwards; total length
7 cm.: west coast of America; common.

2. SCALPELLUM Leach (Fig. 569). Stalk thick, short,
and usually scaly; shell composed of 12 to 15 pieces;
either unisexual or hermaphroditic, with complementary
males: 140 species; mostly in deep water.

S. stroemi Sars. Stalk about half as long as body
and covered with imbricated scales; total length 12 mm.:
in deep water in the gulf of Maine, and to the northward ;
Europe.

FAMILY 2. LEPADIDAE.

Fig. 569

Diagram of

Scalpellum

(Pilsbry).

Explanations as

in Fig. 570.

Stalk much narrower than the rest of the body and without scales;

body flattened and usually covered with a shell consisting of 5 pieces,
a pair of large scuta at the stalk end of the body, a
pair of smaller terga at the opposite end and a
median dorsal carina which lies along the hinge, the
shell opening and the legs protruding on the ventral
side; Anelasma, which lives parasitically in the skin
of dogfish in the North Sea, is without a shell;
hermaphroditic, without complementary males : about
7 genera and 30 species, which attach themselves
usually to floating objects.

1. LEPAS L. Goose barnacles (Fig. 570).
Scuta broad and triangular; terga and carina well
developed, the latter reaching posteriorly between
the former and all 5 parts of the shell abutting on

one another : about 6 species, 5 American, all of which are found on both

coasts.

L. fascicularis Ellis and Solander. Stalk short, not as long as the

body; plates thin and paper-like; carina bent at right angles; length

Fig. 570
Lepas anatifera

(Pilsbry).

1, scutum ; 2, tergum
3, carina.

CIRRIPEDIA

361

Fig. 571

Conchoderma

virgatum

(Pilsbry).

of shell 4 cm.: cosmopolitan, often very numerous, especially in early
summer, on the North American coast, sometimes as far north as the
Bay of Fundy, attached to seaweed and other floating objects; Pacific
coast north of San Francisco.

L. anserifera L. Stalk about as long as the body; plates radially
grooved; length of shell 5 cm.: cosmopolitan.

L. anatifera L. (Fig. 570). Stalk usually as long as
or longer than the body; shell bluish-white; plates faintly
striated; length of shell 5 cm. or less: cosmopolitan; on
ships' bottoms and floating objects; the commonest species;
more southerly than L. fascicularis.

2. CONCHODERMA Olfers. Carina and terga small or
wanting; scuta narrow, the parts of the shell not touching
one another; stalk long and almost 'as broad as the body,
tapering from it to the point of attachment: usually
attached to ships' bottoms, but also to other objects; 3
species.

C. virgatum (Spengler) (Fig. 571). Length, including stalk, 5 cm.;
color grajdsh, with 6 dark longitudinal bands: cosmopolitan.

FAMILY 3. BALANIDAE.

Rock barnacles. No stalk present; body enclosed in a thick cal-
careous shell; this is made up of a number of pieces which are joined
together to form a cylinder, in which the animal lies on its back with
the 6 pairs of thoracic feet uppermost; 2 pairs of hinged plates, cor-
responding to the scuta
and terga of Lepas,
close the aperture of the
cylinder 'and, on open-
ing, permit the legs to
be thrust out and sweep
in particles of food:
incrusted on rocks and
timbersi, etc., often in
great numbers; about 7
genera and 75 species.
BALANUS L. (Fig.

572). Cylindrical shell composed of 6 thick pieces joined by thinner ones;
basis of the shell either membranous or calcareous: about 46 species, of
which 8 occur on the Atlantic coast.

B. balanoides (L.). The common barnacle. Base of shell mem-
branous; tergum with a spur; cylindrical shell of variable shape and

I.

Fig. 572 — Diagram of Balanus (Darwin). A, entire
shell ; B, the animal within the shell. Explanations
as in Fig. 570.

362 CRUSTACEA

with longitudinal ridges; length up to 5 cm.: North Atlantic coast,
extremely common between tide lines.

B. eburneus Gould. Ivory barnacle. Shell low and broad in form
and with a smooth, white exterior; base of shell calcareous: common
from Massachusetts Bay to the West Indies, chiefly below low-water
mark; often in brackish and even fresh water.

B. crenatus Bruguiere. Shell white, up to 34 mm. high and 19 mm.
wide; base calcareous and very thin: Atlantic coast, on stones and
shells in deeper water, also on ships.

B. tintinnabulum (L.). Shell often ribbed longitudinally, reddish
or bluish in color with a calcareous base; up to 6 cm. in diameter and
in length: cosmopolitan, in the warmer seas, often brought to our coast
on the bottoms of vessels; is eaten in many countries.

FAMILY 4. CORONULIDAE.

Similar to the preceding family but differing in that the terga and
scuta, although freely movable, are not hinged with one another; base
of shell membranous: on Cetacea; 4 genera and 7 species.

CORONULA Lamarck. Shell formed of 6 principal pieces and wider
than high; terga and scuta much smaller than the opening: 3 species,
on whales.

C. diadema L. Shell crown-shaped, scuta present, terga very small
or wanting: off the New England coast.

SUBORDER 2. ABDOMINALIA.

Body segmented, surrounded by a voluminous mantle but without
a shell, and with only 3 pairs of feet on the hinder part of the thorax;
unisexual; the animal bores into the shells of mollusks and cirripeds: 2

families.

FAMILY ALCIPPIDAE.

Stalk weak and with a large chitinous disc of attachment; legs
uniramose; mantle opens on the side; males minute, without legs,
attached to the females: 1 genus.

ALCIPPE Hancock. With the above-mentioned characters : 1 species.

A. lampas Hancock. Length 6 mm.; bores in dead Natica shells
which are inhabited by hermit crabs: Woods Hole.

SUBORDER 3. RHIZOCEPHALA.

Body without segmentation, appendages, or shell and sac-shaped, with
a stalk composed of branched thread-like projections which extend into
the body of the host; without intestine; hermaphroditic, with comple-

MALACOSTRACA 363

mentary males : 2 families with about 6 genera and 35 species. The best-
known genera are Sacculina Thompson, with about 6 species, which live
on decapod crabs, forming a thick sac between the abdomen and thorax,
and Peltogaster Rathke, with about 7 species, which live on hermit crabs.
They occur in the North Atlantic off the European coast.

SUBCLASS 2. MALACOSTRACA.*

Crayfish, lobsters, and crabs, and the other higher and larger crusta-
ceans. In all, excepting the Phyllocarida, the body is made up of 20
somites, of which 5 form the head, 8 the thorax, and 7 the abdomen. The
head is invariably fused with one or more thoracic somites, and together
with these, in the Phyllocarida and Thoracostraca, is covered by a shield-
like carapace (Fig. 625,5). The number of pairs of appendages is
typically 19, of which 5 are cephalic, 8 are thoracic, and 6 are abdominal :
the last abdominal somite, which is called the telson, bears no appendages.
The cephalic appendages are the first and second pairs of antennae, one
pair of mandibles, and two pairs of maxillae. The terminal portion of
the antenna is called the flagellum (Fig. 576,1): in many cases more
than one may be present, one of which may be a smaller or so-called
secondary flagellum. The basal portion of the antenna is called the
peduncle (Fig. 576,2). The exopodite of the second antenna is broad
and flat in many forms and is called the antennal scale (Fig. 615,3).

From one to five of the anterior pairs of
thoracic appendages are specially modified to assist
in eating and are called maxillipeds, while the
posterior pairs are called periopods and are used
principally for locomotion (Fig. 576,5). The
thoracic appendages are often prehensile and used
for grasping, in which case the distal segments may
be modified in one of three ways : (1) the terminal
segment may form with the next one a forceps-like
pinching claw or chela as in the crayfish or crab,
when the appendage is spoken of as chelate (Fig.
573, B); (2) the terminal segment may simply
bend back on the next one as in the Amphipoda,

when the appendage is spoken of as subchelate (Fig. 573, A); (3) the
terminal segment may be sharp and spine-like, as in the parasitic isopods.
The abdominal appendages are called pleopods or swimmerets (Fig.

* See "Natural History of Economic Crustaceans," etc., by R. Rathbun, Bull, of
TL S. Fish Com. for 1889, p. 763. "Higher Crustacea of New York City," by F, P.
Paulmeier, Bull. 91 of N. Y. St. Mus., 1905. "Die Siisswasserfauna Deutschlands,"
Heft 11, 1910.

364 CEUSTACEA

579, 4) and have a variety of functions, being locomotory and respiratory
and often serving for the attachment of the eggs or the young. The
appendages are all primarily biramose except the anterior antennae,
although in the adult animal either the exopodite or the endopodite may
be absent and the appendages thus become uniramose. The eyes are either
pedunculate or not. The subclass contains 3 divisions and over 11,200
species.

Key to the divisions of Malacostraca:

«! Abdomen composed of 8 segments; large carapace present. .1. PHYLLOCARTDA

o2 Abdomen of 7 segments or less.

&! Carapace absent ; thorax usually with 7 free segments 2. ARTHROSTBACA

6a Carapace present covering a part or all of the thorax ... 3. THORACOSTRACA

DIVISION 1. PHYIiLOCARIDA.*

Primitive Malacostraca with a thorax bearing 8 pairs of leaf-like
gills, a long abdomen composed of 8 segments bearing 6 pairs of
appendages and with a large carapace enclosing the head, thorax,
and a portion of the abdomen ; eyes pedunculate : 2 genera and 7
species, all marine.

NEBALIA Leach. Caudal
fork (furca) with lateral spines:
4 species.

N. bipes (Fabricius) (Fig.
574). Body slender, compressed,
10 mm. long; genital opening on
the last thoracic segment in the ^ 574_yrtflBfl Wpe. (Packard),

male and on the antepenultimate

segment in the female; eggs carried by the female between the thoracic
feet: North Atlantic, in shallow water, among seaweeds; Europe.

DIVISION 2. ARTHROSTRACA.

Malacostracans of small but not minute size in which the first
thoracic somite (in a few cases the second also) is united with the head,
the remaining 7 being free and appearing as distinct segments; no
carapace present; abdominal somites more or less coalesced, 6 free seg-
ments usually appearing, although the number is very often smaller;
appendages well developed, consisting, when all are present, of 2 pairs
of antennae, 1 pair of mandibles, 2 pairs of maxillae, 1 pair of maxilli-
peds (belonging to the first thoracic segment which is fused with the
head), 7 pairs of periopods and 6 of pleopods; eyes in most cases ses-

* See "The Order Phyllocarida," etc., by A. S. Packard, Twelfth Ann. Rep. U. S.
Geol. Sur. for year 1878, pt. 1, 1883, p. 432. "The Crustacean Nebalia," by A. S.
Packard, Am. Nat., Vol. 16, p. 861.

AMPHIPODA 365

sile; the eggs are carried on the ventral surface of the thorax in a
brood pouch formed by flat projections of the thoracic legs and the
young animals are like the parents in form, there being no metamor-
phosis: 2 orders.

Key to the orders of Arthrostraca :

ax Usually laterally compressed ; very often jumping animals .... 1. AMPHIPODA
Oa Usually dorsoventrally flattened ; many terrestrial and many parasitic.

2. ISOPODA
ORDER 1. AMPHIPODA.*

Body elongated and usually laterally compressed; first 2 pairs of
periopods, which are called gnathopods (Fig. 577, 3 and 4), usually
larger than the others and subchelate, being used for grasping the food ;
gills on the periopods; hinder 3 pairs of pleopods usually adapte'd for
jumping: about 45 families and 2,300 species, which are almost exclu-
sively marine, many species dwelling on the seabeach, burrowing in the
sand or living under stones or decaying vegetation; food consisting
mostly of living or dead animals of all kinds, also of decaying vegetable
matter; a number of species are parasitic; 3 suborders.

Key to the suborders of Amphipoda:

G! Seven free thoracic segments.

&x Head very large, with very large eyes 1. HYPERIIDEA

6, Head and eyes not of unusual size 2. GAMMARIDEA

o, Six free thoracic segments ; abdomen very rudimentary 3. CAPBELLIDEA

SUBORDER 1. HYPERIIDEA.

Head and eyes both very large; maxilliped without a palp; 7 pairs
of thoracic legs present: parasitic or living on or in pelagic animals,
especially medusae; 4 families.

Key to the families of Hyperiidea here described :

OJ Usually found in medusae 1. H YPERIIDAE

aa In the tests of Salpa or Pyrosoma 2. PHBONIMIDAE

FAMILY 1. HYPERIIDAE.

Head large and almost entirely occupied by the enormous eyes;
5 abdominal segments ; mandibular palp present : usually found in large
medusae; about 8 genera.

HYPEKIA Latreille. Gnathopods feeble: several species in Aurelia,
Cyanea, and other medusae; 2 species on the Atlantic coast.

H. galba (Montagu). Periopods with very few setae; length 15
mm. : in Aurelia; coast of New England.

* See "Synopsis of the Amphipoda," by S. J. Holmes, Am. Nat, Vol. 37, p. 267,
1903. "The Amphipoda 1. Gammaridea," by T. R. R. Stebbing, Das Tierreich, 1906.
"The Amphipods of Southern New England," by S. J. Holmes, Bull, of U. S. Fish. Com.,
Vol. 24, p. 457, 1904. "The Freshwater Amphipoda of North America," by Ada L.
Weckel, Proc. U. S. Nat. Mus., Vol. 32, p. 25, 1907.

366 CRUSTACEA

H. medusarum (0. F. Miiller) (Fig. 575). Gnathopods covered
with setae on the sides ; length 12 mm. : found in Cyanea and other
jellyfish; coast of New England, north of Cape
Cod.

FAMILY 2. PHRONIMIDAE.

Head very long dorsoventrally, on the sides
and top of which are the large eyes ; no mandibular

Fig. 575 — Hyperia me- palp present; second antennae rudimentary in the
dusarum (Leunis).

female: about 7 genera.

PHRONIMA Latreille. Fifth pair of periopods with large chelae;
last thoracic segment elongated: 1 species.

P. sedentaria (Forskal). Length 3 cm.: cosmopolitan; each indi-
vidual living in the transparent test of Salpa or Pyrosoma.

SUBORDER 2. GAMMARIDEA.

Seven free thoracic segments and pairs of thoracic legs; maxilli-
ped with a 2 to 4-jointed palp : about 40 families and over lfOOO species.
Key to the families of Gammaridea here described :

Oi Three last abdominal somites normal and not fused together.
6i Body compressed and not flattened.
Ct Last pair of pleopods do not end in a hook.
dv First antennae usually shorter than second.
et First antennae without secondary flagellum.
/! First antennae much shorter than the second.

ffl Two eyes present 1. ORCHESTIIDAE

02 Four eyes present 3. AMPELISCIDAE

/, First antennae but little shorter than second 4. CALLIOPIIDAE

ea First antennae with 2 flagella, posterior periopods very broad.

2. PONTOPOBEIIDAE

d, First antennae usually longer than second, or of nearly the same length.
et Secondary flagellum present ; both pairs of gnathopods usually of

same size 5. GAMMABIDAE

e, Secondary flagellum usually absent; second pair of gnathopods

larger than the first 6. PHOTIDAE

ca Last pair of pleopods end in a hook 7. AMPHITHOIDAE

5, Body flattened, with small abdomen 8. COROPHIIDAE

o. Last 3 abdominal somites fused with caudal stylets 9. CHELUEIDAE

FAMILY 1. OBCHESTIIDAE.

The beach fleas. First antennae much shorter than the second;
mandible without palp; body laterally compressed; second gnathopod
much larger than the first: about 13 genera and 100 species, which live
largely on the seashore and are more or less adapted to a terrestrial life.

Key to the genera of Orchestiidae here described:

«! First antennae shorter than peduncle (long basal segments) of second.
&! Dark-colored animals found on the seabeach 1. ORCHESTIA

6, Whitish animals which burrow in the sand 2. TALORCHESTIA

a, First antennae longer than peduncle of second 3. HYALELLA

AMPHIPODA

367

1. OECHESTIA Leach. Dark-colored amphipods in which the first
antennae are shorter than the basal portion (peduncle) of the second,
and the first gnathopod is subchelate in both sexes: 25 species.

0. agilis S. I. Smith (Fig. 576). First antennae not reaching the
tip of the penultimate joint of peduncle of second antenna; length 14

Fig. 576

Fig. 577

Fig. 576 — Orchestia agilis (Verrill). 1, flagellum of second antenna; 2, ped-
uncle ; 3, first gnathopod ; 4, second gnathopod ; 5, periopods ; 6, jumping legs ;
7, abdomen; 8, thorax. Fig. 577 — Orchestia palustris (Paulmeier). Explanations
as in Fig. 576.

mm.; color brownish: Atlantic coast, under masses of decaying sea-
weed on the shore, as far south as Florida; when disturbed it hops and
runs with great rapidity; Europe.

0. palustris* S. I. Smith (Fig. 577). First antennae reaching
beyond tip of penultimate joint of peduncle of the second antennae;
length 18 mm. ; color brownish : Cape Cod to New Jersey ; on the shore of
salt marshes; Europe.

2. TALORCHESTIA Dana. Whitish, large am-
phipods in which the first antennae are shorter than
the basal portion (peduncle) of the second and the
first gnathopods are subchelate in the male and not
in the female: 20 species.

T. longicornisf (Say) (Fig. 578). Eyes large;
second gnathopods of male very large ; first antennae
just reaching to the tip of the penultimate joint of
the second antennae; length 25 mm.; color whitish,
but sometimes brown: Cape Cod to New Jersey,
common on sand beaches, burrowing in the sand
in the daytime.

3. HYALELLA S. I. Smith (Allorchestes Dana). Small amphipods
in which the first antennae are longer than the basal portion (peduncle)
of the second: 2 species.

* See "The Salt-Marsh Amphipod, Orchestia palustris," by M. E. Smallwood,
Cold Spring Harbor Monographs, III, 1905.

t See "The Beach Flea ; Talorchestia longicornis," by M. E. Smallwood, Cold
Spring Harbor Monographs, I, 1903.

Fig. 578 — Talorches-
tia longicornis (Paul-
meier). A, second
gnathopod of male ; B,
first gnathopod of fe-
male ; C, second gnath-
opod of same.

368

CRUSTACEA

H. dentata (Say) (Fig. 579). Hinder dorsal margin of the first
and second abdominal segments produced to form spines; length 6

mm. : in fresh- water ponds in
the eastern states, where it is
one of the two common fresh-
water species of amphipods,
Gammarus fasiatus being the
other.

Fig. 579 — Hyalella dentata (Paulmeier)
first gnathopod ; 2, second gnathopod ;
periopods ; 4, pleopods ; 5, jumping legs.

FAMILY 2. PONTOPOREIIDAE.

First antennae but little
shorter than the second and
with a secondary flagellum;

mandible with a palp; posterior periopods very broad and modified for
digging: about 8 genera and 22 species.

HAUSTORITJS St. Miiller. Characters as above; small rostrum
present: 1 species.

H. arenarius (Slabber) (Fig. 580). Length 18 mm.; color whitish:
Georgia to Cape Cod; on the seabeach near
high-water mark, where it burrows with
great rapidity; Europe.

FAMILY 3. AMPELISCIDAE.

First antennae some distance in front of
and at least half as long as the second; 4
eyes usually present; last 2 segments of

abdomen fused together: a burrowing family with about 3 genera and
40 species.

AMPELISCA Kroyer. Telson divided by a median cleft; 4 eyes
present ; first antennae about half as long as the second : about 25 species.

A. macrocephala Lilljeborg. Postero-lateral margin of third ab-
dominal segment elongated; head usually as long as the first 3 thoracic
segments; length 15 mm.; color white: Vineyard Sound and north-
wards, living in tubes in the mud; Europe.

A. compressa Holmes. Head considerably shorter than the first 3
thoracic segments; body very compressed; length 6 mm.: common from
Cape Cod to Cape Hatteras.

FAMILY 4. CALLIOPIIDAE.

First and second antennae of nearly the same length; periopods
rather strongly built, the last 3 pairs increasing successively in length:
about 15 genera and 30 species.

AMPHIPODA 369

CALLIOPIUS Lilljeborg. Both pairs of gnathopods large and of
equal size ; terminal abdominal segment slender and not split : 2 species.

C. laeviusculus (Kroyer) (Fig. 581). First and second antennae of
nearly the same length; eyes large; length 16 mm.; color light green:
Cape Hatteras to Greenland, in tide pools
and among seaweed; Europe; North Pacific.

FAMILY 5. GAMMAEIDAE.

Both pairs of antennae long, the first
antennae usually longer than the second and
with a secondary flagellum which is a small
side branch of it; mandible with a palp;

both pairs of gnathopods usually of the same size; terminal pleopods
extending beyond the others: over 50 genera and 250 species, largely in
fresh and brackish waters.

Key to the genera of Gammaridae here described :

Oj Last 3 abdominal segments with small bunches of hairs along hinder margin.

bi First 3 abdominal segments not extended behind 1. GAMMARUS

by First 3 abdominal segments each extended behind as an acute tooth.

2. CARINOGAMMARUS

aa No such bunches of hairs on these segments 3. ELASMOPUS

1. GAMMARUS Fabricius. Telson deeply cleft; last 3 abdominal seg-
ments with bunches of small hairs: over 30 species; in salt and fresh
water; 6 fresh- water species in the United States.

Fig. 582 Fig. 583

Fig. 582 — Gammarus locusta (Paulmeier). Fig. 583 — Gammarus faciatus (Paulmeier).

G. locusta (L.) (Fig. 582). First antennae longer than the second;
secondary flagellum with about 8 joints; length 20 mm.; color greenish:
Arctic Ocean to New Jersey, being very common under stones and in
seaweed along the seashore; Europe.

G. annulatus S. I. Smith. First antennae shorter than the second;
length 15 mm.; no lateral hairs on the fourth abdominal segment: Long
Island Sound to Bay of Fundy,

370 CRUSTACEA

G. fasciatus Say (Fig. 583). First and second antennae of about
the same length; length 15 mm.; color whitish: common in fresh- water
ponds and streams, it and Hyalella dentata being the common fresh-water
amphipods in the eastern states.

2. CARINOGAMMARUS Stebbing. Telson deeply cleft; last 3 abdom-
inal segments with bunches of small hairs and first 3 each with a dorsal
backwards projecting spine: about 9 species.

0. mucronatus (Say) (Fig. 584). Antennae of the same length;
length 15 mm.; color greenish: Cape Cod to Florida, common among
algae and in brackish water.

Fig. 584 Fig. 585

Fig. 584 — Cwinogammarus mucronatus (Paulmeier). Fig. 585 — Elasmopus Icevis

(Paulmeier).

3. ELASMOPUS Costa. First antennae twice as long as the second;
first 3 abdominal segments very large, last 3 small and bent beneath
them: about 9 species.

E. laevis (S. I. Smith) (Fig. 585). Last 3 pairs of abdominal ap-
pendages short and thick ; length 10 mm. ; color brownish ; first gnathopods
small, second large: Cape Cod to New Jersey, under rocks and among
seaweeds near low-tide mark.

FAMILY 6. PHOTIDAE.

First antennae with or without a small secondary flagellum and longer
than the second; mandible with a long palp; second gnathopods larger
than the first: 10 genera and about 40 species.

LEPTOCHEIEUS Zaddach (Ptilocheirus Stimpson). Terminal pleopods
biramose ; both pairs of gnathopods large and chelate ; first antennae with
a minute secondary flagellum: 8 species.

L. pingius Stim. Body thick, and variegated in color; length ,13
mm.: New Jersey to Labrador; common on muddy bottoms.

AMPHIPODA
FAMILY 7. AMPHITHOIDAE.

371

First antennae with or without secondary flagellum and about the
same length as the second; gnathopods large, the second being larger
than the first; last pair of ab-
dominal appendages end in
hooks: about 6 genera and 30
species.

AMPHITHOE Leach. First
antennae without secondary flagel-
lum; head without rostrum; man-
dible with palp: 17 species. Fig. 586 — Amphithoe valida (Paulmeier).

A. valida S. I. Smith (Fig.

586). Antennae of about equal length and less than half as long as
body: New Jersey and Long Island Sound under rocks and among
seaweed.

A. longimana Smith. First antennae as long as the body; gnathopods

stout and elongate; length 9 mm.:
common; Cape Cod to New Jersey,
among eel-grass.

FAMILY 8. COEOPHIIDAE.

Body depressed and abdomen
small; first antennae with or without
secondary flagellum; second antennae
very large: about 11 genera and 45
species ; tube-dwelling.

1. COROPHIUM Latreille. Mandibular palp two-
jointed; no secondary flagellum; second antennae enor-
mously developed in the male; gnathopods feeble: 12
species.

0. cylindricum (Say) (Fig. 587). Length 5 mm.;
color light, sometimes with spots: Maine to New
Jersey, living free or in tubes in the mud or in
sponges, etc.

2. UNICOLA Say. Body depressed; first antennae
with secondary flagellum and a little longer than the
second; telson lamellar, rounded: 8 species.

U. irrorata Say (Fig. 588). Color red, mottled
with white; length 15 mm.; body broad; rostrum dis-
tinct: Labrador to New Jersey; common on sandy or rocky bottoms,
living in tubes, often not of its own construction.

Fig. 587 — CoropMum cylindricum
(Paulmeier).

Fig. 588

Unicola irrorata
(Paulmeier).

372

CEUSTACEA

FAMILY 9. CHELUEIDAE.

Body cylindrical; first antennae short, with secondary flagellum;
second antennae longer than the first and with blade-like flagellum; 4
abdominal segments; 3 pairs of caudal stylets present, the last pair
being nearly as long as the rest of the body, but shorter in the female:
1 genus.

CHELTTRA Philippi. With the characters above given: 1 species.

C. terebrans Phil. Length 6 mm.: New England coast, boring in
submerged timbers, and often doing great damage; Europe.

SUBORDER 3. CAPRELLIDEA.

But 6 free thoracic segments ; abdomen very rudimentary ; body very
elongate : 2 families and about 65 species.

FAMILY CAPEELLIDAE.

Body slender and cylindrical; first antennae longer than the second;
gills confined to third and fourth free thoracic segments, on which
the legs may be wanting: 2 genera, which live among
seaweeds and on hydroids, holding on by the 3 pairs of
long posterior thoracic legs, with about 50 species.

1. CAPRELLA Lamarck. Five pairs thoracic legs;
mandible without a palp; gills and no legs on the second
and third free thoracic segments; abdomen reduced to a
small knob bearing a pair of rudimentary legs in the
male: many species.

C. geometrica Say (Fig. 589). Head with an ante-
riorly projecting spine; antennae of nearly the same
length; length 15 mm.; color variable: Cape Cod to
Virginia; very common.

2. ^GINELLA Broeck. Like Caprella but with a palp
on the mandible: several species.

A. longicornis Krb'yer (Fig. 590).
First pair of antennae twice as long
as the second; body either smooth or
spiny; length 16 mm.; color variable:
Labrador to New Jersey; Europe.

Fig. 589

Caprella

geometrica

(Paulmeier).

Fig. 590 — JZginella longicornis
(Paulmeier).

ORDER 2. ISOPODA.*

Body usually flattened dorsoventrally and with gills on the abdomi-
nal appendages; the anterior pairs of pleopods usually more or less

* See "Synopsis of North American Isopoda," by Harriet Richardson, Am. Nat.,
Vol. 34, pp. 207 and 295. "Monograph of the Isopods of North America," by same,
Bull. U. S. Natl. Mus., No. 54, 1905.

ISOPODA 373

lamellar and functioning as gills or lungs, while the last pair, which
are called uropods (Fig. 602) and have a distinct exopodite and endopo-
dite, are elongated and function as feelers or as swimming fins: about
18 families and over 2,300 species, which are small, creeping or swim-
ming animals, most of them marine, living under stones along the sea-
shore and among seaweed or parasitic on fish; a few live in fresh water,
while several very familiar species are terrestrial.
Key to the families of Isopoda here described :

a, First pair of legs chelate 1. TANAIDAE

a, First pair of legs not chelate.
Z>! Uropods lateral.
cx Uropods with telson forming a caudal fin ; pleopods mostly natatory.

dx Exopodite of uropod arches over base of telson 2. ANTHURIDAE

d, Exopodite of uropod does not thus arch.
^ Abdomen composed of 6 segments.
/! Both branches of uropod well developed.
ffi Not parasitic ; body more or less cylindrical ; eyes usually small.

3. ClROLANIDAI

gt Parasitic on fish.
ht Body broad and flattened ; first 3 pairs of legs prehensile . . 4. MGID\E

ht Eyes large ; legs all prehensile 5. CYMOTHOIDAE

/, The 2 branches of uropod not of same length, the exopodite being

minute ; animal bores in wood 6. LIMNORIIDAE

e. Abdomen composed of 2 segments. . 7. SPH^ROMIDAE

c, Uropods arch over the other pleopods, covering them 8. IDOTHEIDAE

&, Uropods terminal.
Cj Animals aquatic.

dx First antennae much smaller than the second, but not minute.
6j Animals not parasitic.

/i Fresh-water forms 9. ASELLIDAE

/2 Marine forms 10. JANIEIDAE

ea Animals parasitic on decapods 15. BOPYRIDAE

d3 First antennae minute and not easily seen 13. LIGYDIDAE

c, Animals terrestrial (occasionally aquatic).
dt Cannot roll itself into a ball (except CyUsticus convexus).

€i End segment of abdomen pointed or angular 11. ONISCIDAI

e2 End segment truncate or indented ... 14. TRICHONISCIDAE
d2 Can roll itself into a ball 12. ARMADILLIDIDAE

FAMILY 1. TANAIDAE.

Body more or less cylindrical, with 6 free thoracic
segments; first pair of legs chelate; abdominal append-
ages, when present, natatory; gills on the thoracic append-
ages: about 16 American species; marine.

1. TANAIS Audouin and Edwards. Only 3 pair of

pleopods present; uropods uniramose and short: 5 Amer- Tanaiscavolini

(Harger).
ican species.

T. cavolini Milne-Edwards (Fig. 591). Body slender, abdomen with
5 segments; uropods 3-jointed; length 4 mm.; width 1 mm.: Greenland
to Long Island Sound ; in shallow water on piles and among seaweed.

374

CRUSTACEA

Fig. 592

Leptochela

savignyi

(Harger).

2. LEPTOCHELA Dana. Male with large, female with small chelae;
5 pairs of pleopods present ; uropods biramose ; eyes present : 5 American
species.

L. savignyi (Kroyer) (Fig. 592). Chela of male elongated; exopo-
dite of uropods composed of 1, endopodite of 6 segments;
length 2 mm.; color white: New Jersey to Cape Cod;
among seaweed and at the surface; Europe.

FAMILY 2. ANTHUBIDAE.

Body cylindrical and elongate, with 7 free thoracic
segments; abdomen relatively short, with its anterior
somites often fused together; uropods lateral, large, and
expanded, the outer branch (exopodite) arching over the
telson: about 15 species, 9 American.

CYATHURA Norman and Stebbing. First 5 abdominal
segments fused together so as to resemble an eighth
thoracic ; maxillipeds 3-jointed : 1 American species.

C. carinata (Kroyer) (Fig. 593). Both pairs of
antennae short and thick and with few hairs; length 18
mm.; breadth 2 mm.; color brownish or yellowish: New
Jersey to Greenland; on sand and mud bottoms in shallow
water and among seaweed; Europe.

FAMILY 3. CIROLANIDAE.

Body semicylindrical and broad ; abdomen composed Fig. 593

Cyathura
of 6 segments; uropods lateral, forming with the telson a carinata

caudal swimming fin: 23 American species.

CIROLANA Leach. First 3 pairs of legs prehensile, last 4 pairs
ambulatory; first and second pair similar to each other:
14 American species.

C. concharum (Stimpson) (Fig. 594). Length 23 mm.;
breadth 8 mm.; telson triangular; base of uropods is
extended posteriorly beneath the margin of the telson
two-thirds of its length: South Carolina to Nova Scotia
on muddy and sandy bottoms in shallow water, feeding
on the blue crab and other animals.

Fig. 594

Cirolana

concharum

(Harger).

FAMILY 4. ^EGIDAE.

Body broad and more or less flattened ; head short and
broad, usually with 2 very large eyes on its upper surface; first 3 pairs
of legs prehensile; uropods lateral and forming a caudal fin with the
telson : parasitic on the skin of fish ; 30 American genera.

1SOPODA

375

JEGA Leach. Body elliptical in outline ; basal segments of first anten-
nae expanded and lying entirely in front of the head : 14 American species.

A. psora (L.). Salve bug (Fig. 595). Length 16 mm.; breadth 10
mm.: parasitic on the skate, cod, halibut, and other fishes;
used as a salve by fishermen; Long Island Sound to
Greenland; Gulf of Mexico; Europe.

FAMILY 5. CYMOTHOIDAE.

Head triangular, with large eyes, and extending over
the base of the short antennae; all 7 pairs of legs pre-
•hensile, terminating in hooks: parasitic on fishes; over
100 species, 27 American.

LIVONECA Leach. Body elliptical, more or less
asymmetrical; first pair of antennae widely separated at the base: 5
American species.

L. ovalis (Say). Length 21 mm.; width 13 mm.:
parasitic on the gills and in the mouth of the bluefish and
occasionally of other fishes along the Atlantic coast south
of Cape Cod, and in the Gulf of Mexico.

Fig. 595
JEga psora
(Harger).

FAMILY 6. LIMNORIIDAE.

Body flattened and with parallel sides; can roll itself
into a ball; antennae short; eyes lateral; uropods lateral;
legs ambulatory: 1 genus.

LIMNORIA Leach. With characters of family : 1 species.
L. lignorum (Rathke). Gribble (Fig. 596). Length 3 mm.; width
1.5 mm. : Florida to Labrador ; Europe ; Pacific' coast ; makes burrows
about 12 mm. deep in submerged timbers, causing
great damage to docks, etc.; very common.

FAMILY. 7. SPH^EOMIDAE.

Body short, oval, and convex, and in many species
can be rolled into a ball; but 1 abdominal segment
besides the large telson; inner branch of uropod
immovable: 30 American species.

SPH^ROMA Latreille. Uropods large, lateral, the
2 branches being of equal length, the outer margin of
the exopodite being denticulate; legs ambulatory: 3
American species.

S. quadridentatum Say (Fig. 597). Body can be rolled into a ball;
length 8 mm.; width 4 mm.; color dark and variable: Florida to Cape
Cod; under stones between tide lines.

Fig. 597

Sphcvroma

quadridentatum

(Harger).

376

CRUSTACEA

FAMILY 8. IDOTHEIDAE.

Body more or less broad and flattened ; often elongate ; abdominal seg-
ments partially or completely fused ; uropods lateral, arching over and cov-
ering the other pleopods under the abdomen : about 90 species, 40 American.

Key to the genera of Idotheidae here described :

d Side of head cleft and extending beyond eyes 2. CHIBIDOTEA

az Side of head not extended in dorsal view.
&! Second antennae with a long flagellum ; abdomen of several segments.

1. IDOTHEA
63 Second antennae without a long flagellum ; abdomen a single segment.

cx Second antennae not much longer than head 3. EDOTEA

ca Second antennae very much longer than head 4. ERICHSONELLA

1. IDOTHEA Fabricius. Second antennae with a long flagellum and much
larger than the first; legs all alike; abdomen composed
of 3 complete and 1 partial segment : 8 American species.
I. baltica (Pallas) (Z. marina L. ; I. irrorata Say)
(Fig. 598). Length 20 mm.; width 7 mm.; color often
green, but very variable; abdomen ending in three projec-
tions: Nova Scotia to North Carolina; cosmopolitan; on
seaweed, in sand or at the surface; common.

I. phosphorea Harger. Length 21 mm. ; width 7 mm. ;
color variable ; abdomen tapering to a point : coast of
New England, among rocks and seaweed.

I. metallica Bosc (I. robusta Kroyer). Length 18
8 mm.; abdomen truncate: entire Atlantic coast; cosmo-
politan; often on floating seaweed.

Fig. 598

Idothea baltica
(Harger).

mm.; width

Fig. 599

Fig. 600

Fig. 601

Fig. 599 — Chiridotea cceca (Harger). Fig. 600 — Edotea triloba (Harger).
Fig. 601 — Erichsonella flliformis (Harger).

2. CHIRIDOTEA Harger. Second antennae usually with a short fla-
gellum, sides of head cleft at the eye and extending beyond it; first 3
pairs of legs prehensile, last 4 pairs ambulatory; abdomen composed of
4 segments : 2 species.

C. caeca (Say) (Fig. 599). Body ovate, with a long, pointed telson;
length 8 mm. ; width 4 mm. ; antennae of nearly equal length ; eyes small,
dorsally placed: Florida to Nova Scotia; at the surface or in the sand.

ISOPODA 377

3. EDOTEA Guerin. Second antennae of 4 to 6 segments and short ;
abdomen composed of a single segment; legs prehensile: 3 species.

E. triloba (Say) (Fig. 600). Length 7 mm.; width 3 mm.: New
Jersey to Maine; under stones and decaying algae, in muddy places
along the shore.

4. ERICHSONELLA Benedict. First antennae short ; second antennae
long and composed of 6 segments; abdomen composed of a single seg-
ment; legs ambulatory: 3 American species.

E. filiformis (Say) (Fig. 601). Length 8 mm.; width 3 mm.: At-
lantic coast, south to Cape Cod ; in sand and among algae in shallow water.

FAMILY 9. ASELLIDAE.

Body flattened, with 7 free thoracic segments, and with the ab-
dominal segments forming a single, shield-like plate; abdominal append-
ages exclusively branchial and numbering 4 or 5 pairs; uropods terminal
and biramose: principally fresh-water animals; 17 American species.

Key to the genera of Asellidae here described:
Oj Eyes present.

6j Last 6 pairs of legs uniunguiculate 1. ASELLUS

6, Last 6 pairs of legs biunguiculate 2. MANCASELLUS

oa Eyes absent ; cave-dwellers 3. C^ECIDOTEA

1. ASELLTTS Geoffrey. Abdomen about as broad as long; legs uniun-
guiculate; mandible with a palp: 7 American species; in fresh water.

A. communis Say (Fig. 602). Length 15 mm.; breadth 5 mm.; first
antennae short, second long; first pair of legs prehensile and subchelate,
the others ambulatory, the last 3 being longer than the others: eastern
United States; the commonest
fresh-water isopod, occurring
generally among vegetation.

2. MANCASELLUS Harger.
Abdomen about as broad as

Inner- manrlihlp withnnt ft nnln- Fte- 602 — Diagram of Asellus communis,

Ong, n B Wltnout a paip, showfeing the int|rnal organs (McMurrich)'

last 6 pairs of legs biun- J^-econd ^nna ; fJS&Sttlut
guiculate: 6 species; in fresh ^^ ^fg? ^ heart; 9' intes'
water.

M. macrourus Garman. Length 12 mm.; breadth 5 mm.; first pair
of legs subchelate, the others ambulatory ; side of the head cleft near the
eye: central United States east of the Mississippi, often in caves.

3. CJECIDOTEA Packard. Body elongate and narrow; eyes wanting;
abdomen much longer than broad: 4 species; in caves and similar places.

C. stygia Pack. Length 10 mm.; width 2 mm.; first pair of legs
prehensile, the hand being armed with 2 long and 3 short teeth: central
United States; in caves and deep wells.

378

CRUSTACEA

FAMILY 10. JANIEIDAE.

Body flattened and similar to the Asellidae, with the side of the head
usually expanded under the eye; first pair of abdominal appendages in
the female form a single large opercular plate, and
in the male together with the second pair form
a compound operculum: 20 American species;
marine.

1. JJERA Leach. First pair of antennae very
small; uropods very small: 2 American species.
J. marina (Fabricius) (Fig. 603). Body
oval, 5 mm. long, 2 mm. wide, and very variable
in color, usually being mottled gray; legs ambu-
latory and triunguiculate : coast of New England ;
Europe; common between tide lines under stones
and seaweeds.

2. JANIRA Leach. First pair of antennae and uropods well devel-
oped ; side of head not expanded, or but slightly so : 5 American species.

J. alta (Stimpson) (Fig. 604). Length 7 mm.;
width 2 mm.; legs biunguiculate : Atlantic coast from
Nova Scotia to Virginia, from low-water mark to 500
fathoms.

FAMILY 11. ONISCIDAE.

Fig. 603 — J&ra marina
(Harger).

Fig. 604— Jantra
alta (Harger).

The sow bugs. Terrestrial isopods with an
elliptical body, which is more or less flattened and
cannot be rolled into a ball (except Cylisticus con-
vexus) ; first antennae minute; second antennae long;
thorax with 7 and abdomen with 6 free segments;
legs ambulatory; 5 pairs of pleopods are respiratory plates, the second
pair in the male terminating in a pair of long slender stylets; uropods
long and terminal: common under logs, etc., and in other dark, damp
places on the land; 200 species, 30 American.

Key to the genera of Oniscidae here described:

ax Antennae ending with 3 short segments forming the flagellum.

6X Abdomen not abruptly narrower than thorax 1. ONISCDB

62 Abdomen abruptly narrower than thorax 2. PHILOSCIA

o. Antennae ending with a flagellum of 2 short segments.
Z>! Abdomen not abruptly narrower than thorax.

<?! Body convex, can be rolled into a ball 3. CYLISTICUS

c. Body flattened, cannot be rolled into a ball 4. POBCELLIO

6, Abdomen abruptly narrower than the thorax 5. METOPONOBTHUS

1. ONISCUS L. Body broad, flattened, with a granulated or tuber-
culated surface; antennae ending with 3 short segments; side of head
extended beneath the eyes: 1 species.

ISOPODA

379

Fig. 605 — Oniscus
asellus (Paulmeier).

0. asellus L. (Fig. 605). Length 16 inm.; width 8 mm.; color deep
slate, spotted with white, and white along the lateral edges: eastern and
central states ; Europe ; common under bark of fallen
trees, logs, stones, etc.

2. PHILOSCIA Latreille. Second antennae ends
with 3 short segments; side of head not extended
under the eyes ; abdomen abruptly narrower than the
thorax: 7 American species.

P. vittata Say (Fig. 606). Length 8 mm.; width
4 mm.; color usually dark brown with 2 darker
median stripes : along the seashore from New Jersey
to Cape Cod, under stones and boards above high tide.

3. CYLISTICUS Schnitzler. Body rather elongate,
smooth, very convex, and able to be rolled into a
ball; head with lateral lobes; second antennae long,

ending with 2 short segments; uropods long: 1 Amer-
ican species.

C. convexus (DeGeer) (Fig. 607). Length 12 mm.;
width 5 mm.; color brown or dark gray, spotted with
white: eastern and central states; Europe; under logs
and stones in rather dry places.

4. PORCELLIO Latreille. Body oval, flattened; head
with lateral lobes; second antennae long, ending with 2
short segments; uropods long; respiratory plates of
either the first 2 or all 5 pairs of pleopods provided
with tracheae: 6 American species.
P. rathkei Brandt. Body granulate, 10 mm. long and 5 mm. wide,
yellowish-brown in color with numerous black blotches and two lateral

Fig. 606

PMloscia vittata
(Harger).

Fig. 607

Fig. 608

Fig. 609

Fig. 607 — Cyllsticus convexus (Paulmeier). Fig. 608 — Porcellio scaber (Paulmeier).
Fig. 609 — MetoponortJtus pruinosus (Paulmeier).

and usually a median light stripe : eastern and central states ; Europe ;
common under boards, stones, etc.

380

CRUSTACEA

P. scaber Lat. (Fig. 608). Body covered with minute tubercles, 12
mm. long, 7 mm. wide, of unif orm black color, without spots or blotches :
entire America; cosmopolitan; under bark, logs, etc.

P. laevis Lat. Body smooth or minutely granulate, 15 mm. long, 8
mm. wide, dark gray in color with 2 wavy median lighter bands: entire
America; cosmopolitan.

5. METOPONORTHUS Budde-Lund. Body oval, flattened, without lat-
eral lobes; second antennae long, ending in 2 short segments; abdomen
abruptly narrower than thorax; uropods long: 4 American species.

M. pruinosus (Brandt) (Fig. 609). Length 9 mm.; width 4 mm.;
color reddish-brown in the hinder and lateral portions, and lighter in
the other portions: entire America; cosmopolitan; under logs, etc.

FAMILY 12. ARMADILLIDIDAE.

Body convex and able to be rolled into a ball; first antennae minute;
second antennae short; uropods short and not extending beyond the

terminal segment: terrestrial; 6 genera
and 23 American species.

ARMADILLIDIUM Brandt. Pill bugs.
With the characters of the family; exopo-
dite of uropod large and lamellar; ter-
minal segment triangular: 2 species.

A. vulgare (Latreille) (Fig. 610).
Length 16 mm.; width 8 mm.; color black
or dark gray with rows of indistinct spots: entire America; cosmo-
politan: under stones, etc., in damp places.

Fig. 610 — Armadittidium vulgare
(Paulmeier).

FAMILY 13. LIGYDIDAE.

Body elliptical or elongate; first antennae minute; second antennae
long, with numerous small terminal segments; buccal
mass prominent; uropods long: marine; 2 genera and
12 American species.

LIGYDA Rafinesque. The two branches of the
uropods of about equal length and stylifonn: 6
American species.

L. exotica (Roux) (Fig. 611). Body elongate, 48
mm. long (with uropods), 14 mm. wide: Florida to
North Carolina; California; cosmopolitan; among
rocks and on piles and docks; common.

L. oceanica (L.). Body oval, 22 mm. long (with uropods), 8 mm.
wide, and with a granulate surface: New England; Europe.

Fig. 611
Ligyda exotica
(Richardson).

ISOPODA 381

FAMILY 14. TEICHONISCIDAE.

Body elliptical, elongate; first antennae minute; second antennae end-
ing with 3 or 5 small segments ; abdomen not pointed behind, but truncate
or indented ; the 2 branches of each uropod of about the same length : 4
American species; terrestrial or in fresh water.

TRICHONISCTJS Brandt. Head rounded in front; eyes small, composed
each of 3 ocelli; second antennae long; abdomen abruptly narrower than
thorax: 2 species.

T. pusillus Br. (Fig. 612). Length 3 mm.; width 1
mm.; body smooth: entire North America; Europe;
under moss, in the woods.

FAMILY 15. BOPYRIDAE.

Parasites of decapods; male and female animals
dissimilar, the female being asymmetrical and broad, and
sometimes much deformed, the male more slender and
symmetrical; antennae rudimentary; legs prehensile: 35
species, 29 American.

1. PROBOPYRUS Giard and Bonnier. Segments of THch'oniwus
abdomen distinct in female, but fused, except at the (R^hardson)
edges, in the male; 5 pairs of abdominal appendages;

uropods wanting : parasites in the gill chamber of decapods ; 5 American
species.

P. pandalicola (Packard). Body (of female) 5 mm. long, white in
color with black markings ; the female lies against the body of the host,
the ventral side of the thorax having the brood pouch with the eggs,
the much smaller male is usually found clinging to the female: entire
Atlantic coast, on Palcemonetes, producing large tumors under the
carapace.

2. PHRYXUS Rathke. Body of female very asymmetrical, one side
being greatly swollen ; 5 abdominal segments ; the legs of the longer side
of the body wanting, except on the first thoracic segment, on the shorter
side very small; antennae and uropods rudimentary; abdomen of male
composed of a single triangular segment, without appendages: parasitic
on the abdomen of decapods; 1 species.

P. abdominalis (Kroyer). Body of female 9 mm. long, 7 mm. wide;
of male 3 mm. long and 1 mm. wide : circumpolar, extending to Vineyard
and Puget Sounds; on the abdomen of Pandalus and other prawns.

3. BOPYROIDES Stimpson. Body of female somewhat asymmetrical,
with 6 abdominal segments and 7 pairs of legs, without abdominal ap-
pendages; abdomen of male forming a single piece without appendages;
antennae rudimentary: 1 species.

382 CRUSTACEA

B. hippolytes Kroyer. Body of female 8 mm. long and 7 mm. wide;
of male 3 mm. long and 1 mm. wide: circumpolar, extending to Boston
and to Puget Sound; on the gills of Pandalus and other prawns.

DIVISION 3. THORACOSTRACA.*

Malacostraca often of large size in which 3 or more of the thoracic
somites are fused with the head, and the cephalothorax thus formed is
covered with a carapace; projecting forwards from the anterior end of
the carapace in most species is the spike-like rostrum ; eyes at the end of
movable stalks or peduncles (except in the Cumacea) ; the sixth pair of
pleopods (uropods) together with the last body segment (telson) forms,
except in the case of the crabs, a swimming fin, by striking which vigor-
ously beneath the body the animal propels itself rapidly backwards;
the eggs and sometimes the young usually carried beneath the abdomen
attached to the pleopods, the young in most forms passing through a
metamorphosis before attaining the form of the parents: 4 orders.

Key to the orders of Thoracostraca :

a^ Carapace does not cover the entire thorax.

6t Thoracic appendages all biramose 1. SCHIZOPODA

oa Thoracic appendages not all biramose.
ca Abdomen large and wider than the small cephalothorax. . .2. STOMATOPODA

c2 Abdomen narrow 3. CUMACEA

o. Carapace covers the entire thorax 4. DECAPODA

ORDER 1. SCHIZOPODA.

Body elongate and usually more or less transparent and with a thin
carapace which covers nearly all of the thorax; the 8 thoracic feet may
all support gills and are biramose, the anterior 2 pairs being slightly
modified to form maxillipeds; eggs carried beneath the thorax as in the
Arthrostraca; young born in some species as nauplii: 3 families and
about 300 species, mostly marine; 11 American species.

FAMILY MYSIDAE.

No gills present; first 2 pairs of thoracic appendages (maxillipeds)
shorter than the following 6; abdominal appendages often rudimentary
in female; the endopodites of the uropods bear each an auditory sac;
2 to 7 pairs of marsupial plates beneath the thorax within which the
young develop: 21 genera and 90 species, mostly marine.

1. MYSIS Latreille. Body laterally compressed; fourth pair of ab-
dominal appendages in male are long stilets; antennal scale long: often
in swarms in the North Atlantic; 23 species, 4 American, 1 in fresh
water.

• See "The Stalk-eyed Crustaceans of the Atlantic Coast," etc., by S. I. Smith,
Trans. Conn. Acad., Vol. 5, p. 27,

STOMATOPODA

383

M. stenolepis S. I. Smith (Fig. 613). Body cylindrical; carapace
with a short, blunt rostrum, and with its lower anterior margin extended
to form a sharp tooth; body bends between the first and second abdom-
inal segments; length, male,
23 mm.,, female, 30 mm.;
color white, with black stel-
late spots: coast of New

England and southwards,

Fig. 613 — Mysis stenolepis (Paulmeier).
often common in eel grass.

M. relicta Loven (Fig. 614). Body slender, 18 mm. long:
in Lakes Superior and Michigan; Europe and
Asia, in large fresh-water lakes.

2. HETEROMYSIS S. I. Smith. First pair of thoracic

legs larger than the others
and ending each with a
claw; antennal scale very
small; abdominal append-
ages rudimentary in both
male and female: one

Fig. 614 — Mysis relicta (Siissw. F. Deut.).
1, flagella of first antenna ; 2, scale of second
antenna ; 3, second antenna.

species.

H. formosa Smith. Length of male 6 mm., of female 8.5 mm.j
females rose-colored; males colorless: coast of New
England, in eel grass or often in dead mollusk shells,
sometimes in swarms.

ORDER 2. STOMATOPODA.*

Body large, with a small flat carapace which does
not cover the posterior thoracic somites, with a broad
elongated abdomen bearing gills on the appendages; 5
pairs of maxillipeds, the second pair being much larger
than the rest and subchelate, and 3 pairs of periopods;
heart long and tubular; liver, testes, and ovaries extend-
ing the length of the thorax and abdomen, the testes
being a pair of delicate tubes and the ovaries a broad
median band: 10 genera and about 90 species, all
marine; often used for food.

SQUILLA Fabricius. Five posterior thoracic
somites not covered by the carapace, of which the first
is very small and the second has a lateral spur on each side and the last
3 bear the periopods : 21 species.

Fig. 615 — Squilla
empusa (Paul-
meier). 1, first an-
tenna ; 2, second
antenna ; 3, scale
of second antenna ;
4, second maxilli-

§ed ; 5, periopods ;
, uropod.

* See "Report on the Crustacea of the Order Stomatopoda," etc., by R. P, Biglow,
Proc. U, S, N, Mus., Vol. 17, p. 489, 1891.

384 CRUSTACEA

S. empusa Say (Fig. 615). First antennae with 3 flagella; second
shorter and with a very large flat scale (exopodite) ; length up to 25
cm.; color greenish-gray: Florida to Cape Cod, in shallow burrows in
the mud, between tide lines and in shallow water, each burrow usually
having 2 or 3 openings a few feet apart; often very common.

ORDER 3. CUMACEA.

Body small, with a small carapace which does not cover the hinder
4 or 5 thoracic somites, and with a long slender abdomen; first anten-
nae short; second antennae short in the female and long in the male;
mandibles without palp; 2 pairs of maxillipeds and 6 pairs of periopods
present, 2 to 5 pairs of the latter being biramose (small exopodite pres-
ent) ; the pleopods, with the exception of the uropods, wanting in the
female, while in the male 2 to 5 pleopods may be present; a single pair
of gills on the first pair of maxillipeds; eyes close together and sessile or
wanting ; the large eggs are carried by the female in a brood pouch under
the foremost free thoracic segments and the hinder part of the cara-
pace; the young animals are like the parents in appearance, but are
without the last pair of thoracic and all the abdominal legs when born:
9 families and about 300 species, all marine and living mostly in the sand
and mud.

FAMILY DIASTYLIDAE.

With the characters given above: 8 American genera.

DIASTYLIS Say. Seven abdominal segments present, the telson
being well developed and long and pointed; a single eye or none; the
3 anterior pairs of periopods in the female
and the 5 in the male biramose: numerous
species, several American.

D. quadrispinosa G. O. Sars (Fig.
616). Length 10 mm.; body flesh color or Fig*
brownish; a short spine projects from the

carapace on each side a little behind the large triangular rostrum: Nova
Scotia to New Jersey in 2 to 200 fathoms; often very common.

ORDER 4. DECAPODA.

Shrimps, crayfish, lobsters, and crabs. Thoracostracans in which
the carapace covers the entire thorax, the cephalothorax being cylindrical
in the Macrura and broad and more or less flattened in the Brachyura;
gills on the thorax, extending either from the legs (podobranchs), the
joints (arthrobranchs), or the body wall (pleurobranchs) and situated
in the gill chamber on each side of the body (Fig. 623) ; abdomen well

DECAPODA 385

developed in the former group and small and bent under the cephalo-
thorax in the latter; 3 pairs of maxillipeds and 5 pairs of periopods
present; first pair of periopods (chelipeds) usually much larger than the
others and chelate, forming the pinching claws (chelae) ; other periopods
also often chelate ; eggs and sometimes the young carried on the pleopods :
about 6,000 species, mostly marine; the crayfish, certain crabs, and a few
others being fresh-water or terrestrial animals; 2 suborders.
Key to the suborders of Decapoda:

ax Body more or less cylindrical and elongate; antennae long; tail fin

usually present 1. MACBUBA

a2 Cephalothorax short and broad, with the abdomen bent under it ; crabs.

2. BBACHYUBA
SUBORDER 1. MACRURA.*

Body more or less cylindrical and elongate with a well-developed
abdomen, at the hinder end of which is usually a swimming fin formed
of the sixth pair of pleopods (uropods) and the telson; antennae well
developed and usually long, the first antenna having 2 or more flagella,
the second usually with an antennal scale; the young are born as nauplii
in Peneus and Lucifer, but in most other forms in a more advanced larval
stage: about 10 American families grouped in 4 tribes.

Key to the tribes of Macrura :

at Last pair of thoracic feet normal ; swimming fin present.
&x Shrimps and prawns ; body rather small and transparent ; antennal

scale large (Fig. 617) 1. CABIDEA

62 Burrowing marine animals of moderate size; antennal scale usually

absent 2. THALASSINIDEA

63 Crayfish and lobsters ; body of moderate or large size, with small anten-

nal scale, or none 3. ASTACIDEA

a2 Last pair of thoracic feet reduced and projecting upwards ; no swimming

fin ; hermit crabs, etc 4. ANOMUBA

TRIBE 1. CABIDEA. t (MACRURA NATANTIA.)

Shrimps and prawns. Small forms with a compressed and more or
less transparent body; carapace smooth, without sutures and with a long
rostrum; antennal scale large; thoracic legs usually long and delicate:
about 17 families and several hundred species.

Key to the families of Caridea here described :

ot First 3 pairs of periopods not all chelate.
&! Second pair of periopods only chelate ; first pair very stout and sub-

chelate 1. CBANGONIDAE

&2 First 2 pairs of periopods usually chelate ; first antennae with 3 flagella. ^

2. PAL^MONIDAE
o2 First 3 pairs of periopods chelate 3. PENEIDAE

• See "Embryology and Metamorphosis of the Macroura," by W. K. Brooks and
F. H. Herrick, Mern. Nat. Acad. Sci., Vol. 5, 1892.

t See "Synopsis of the Caridea of North America," by J. S. Kingsley, Am. Nat.,
Vol. 33, p. 709, 1899.

386 CRUSTACEA

FAMILY 1. CRANGONIDAE.

Shrimps. Second antennae long, with a large antennal scale; first pair
of periopods much stouter than the others and subchelate; second pair of
periopods small and chelate; mandibles slender, not bifid or expanded at
the tip and without a palp: marine; about 10 American genera.

CBANGON Fabricius. Cephalothorax
somewhat depressed; rostrum short; first
antennae with 2 flagella: 15 species, about 8
American.

C. vulgaris Fabr. The edible shrimp
(Fig. 617). Length 5 cm.; color light, with
dark markings: Labrador to South Caro-
lina; Europe; Pacific coast; common at the
bottom of sandy bays, in shallow water, often
buried in the sand.

C. boreas (Phipps). Three median dor-

^second 'antenna?*10 sal spines on cephalothorax : Atlantic coast as
far south as Cape Cod; North Pacific coast.

C. franciscorum Stimpson. The California shrimp. Length 7 cm.;
posterior margin of fifth abdominal segment with a spine on each side;
movable finger of cheliped long and parallel with the hand: common at
San Francisco.

FAMILY 2. PAL^MONIDAE.

Prawns and shrimps. Second antennae long, with a large antennal
scale ; first antennae with 3 flagella ; third maxillipeds foot-like ; mandibles
with a bifid tip ; rostrum long and usually serrate : mostly marine ; about
12 American genera.

Key to the genera of Paltzmonidae here described :

«! Right and left claws of the first pair of periopods of the same size.
&! First pair of periopods shorter but not thicker than the second.
Ci First 2 pairs of periopods chelate.

di Mandibular palp absent 1. PAL^EMONETES

d, Mandibular palp present 2. PAL^EMON

c2 First pair of periopods not chelate 3. PANDALUS

6, First pair of periopods thicker than the second ; abdomen bent down at
the third segment.

Cj Mandibular palp present 4. HIPPOLYTE

c2 Mandibular palp absent 5. VIBBIUS

a, Right and left claws of the first pair of periopods of different size. .6. ALPHEUS

1. PALS:MONETES Heller. Mandibles without palp; first 2 pairs of
periopods chelate, the first pair being smaller than the second: about 6
species, 3 American, in salt, brackish, and fresh water.

DECAPODA

387

Fig. 618 — Palcemonetes vulgaris (Verrill).

P. vulgaris (Say). Common prawn (Fig. 618). Rostrum long,
straight and serrate; length 45 mm.; body translucent, with brownish
spots: Massachusetts to Florida; common on rock weed, and eel grass
on muddy bottoms, often where the water is brackish or fresh.

P. paludosa (Gibbes).
Length 35 mm.; rostrum serrate
below as well as above: in
fresh-water lakes and streams
in eastern North America (Lake
Erie, etc.).

2. PAUEMON
Fabricius. Like
Palaemonetes but

with a 3- jointed mandibulary palp (Fig. 619) : about 70 species, 3
American; in salt and fresh water.

P. ohionis S. I. Smith. Length 6 cm.; carapace about a quarter the
length of the body, with a lateral spine on each side: Ohio and Missis-
sippi Rivers; often used for food.

3. PANDALUS Leach. Deep-water prawns. First
and second pairs of periopods slender, the first
not chelate, the second chelate: 10 American
species.

P. montagui Leach. Length 10 cm.; body with
transverse red stripes; appendages thickly spotted
with red: Chesapeake Bay to Greenland; Europe; in
10 to 100 fathoms.

4. HIPPOLYTE Leach. First 2 pairs of periopods chelate, the first
pair shorter and thicker than the second; abdomen sharply bent down
at third segment; mandibular palp present: numerous species, about
30 American.

H. pusiola Krb'yer. Length 25 mm. ;
pale gray or flesh color, brightly spotted
with red, usually with a mid-dorsal
white stripe, and sometimes
Avith transverse bands of red
and white: often common on
rocky bottoms in shallow water from Vineyard Sound to Greenland;
Europe.

5. VIRBIUS Stimpson. Similar to Hippolyte but without a man-
dibular palp: many species, 2 American.

V. zostericola S. I. Smith (Fig. 620). Rostrum straight and as
long as the carapace, the latter being smooth and with 3 spines on an-

Fig. 619 — Mandible

of Palcemon,

showing palp

(Smith).

Fig, 620 — Virbius zostericola
(Smith).

388 CRUSTACEA

terior part j abdomen sharply bent at the third segment ; length 15 to 26
mm. ; color translucent, usually greenish and spotted with red : Vineyard
Sound and southwards, common in eel grass.

6. ALPHETJS Fabricius. First pair of periopods larger than the
others and chelate, the right and left claws of the first pair being thick

and of very unequal size; rostrum small
or absent; abdomen not sharply bent;
eye stalks short and hidden: about
one hundred species, twelve American,
living principally along our southern
coasts.

A. minus Say. Rostrum present;
hinder feet with spines beneath; length
Fig. 621— Mpkeus^heterochelis 4 cm.: Atlantic coast from New Jersey

to Florida; southern Calif ornian coast.

A. heterochelis Say (Fig. 621). Large claw with a constriction at
its middle; rostrum spiniform; length 5 cm.: Virginia to Florida;
California.

FAMILY 3. PENEIDAE.

Southern shrimps and prawns. First 3 pairs of periopods chelate,
the third pair being the largest ; rostrum long ; second antennae long, with
a large scale; abdomen compressed and not bent sharply: about 2
American genera, marine, inhabiting chiefly the tropics and the deep sea.

PENEITS Latreille. Rostrum serrate; eye stalks jointed; the young
born as nauplii: 3 American species.

P. setiferus (L.). A lateral groove on each side of the forward half
of the carapace ; flagella of first antennae very short ; length up to 16 cm. :
common in shallow water along the coast from Virginia southwards,
where it is an article of food, the larger individuals being known in the
market as prawns and the smaller as shrimps.

P. brasiliensis Latreille. Like P. setiferus, but with the lateral
grooves extending the length of the carapace: Atlantic coast north
to Cape Cod, occurring with P. setiferus.

TRIBE 2. THALASSINIDEA.*

Animals of moderate size, with a cylindrical or flattened and trans-
lucent body and a large abdomen; carapace with 2 longitudinal sutures;
antennal scale usually wanting; first pair of periopods form pinching
claws of unequal size: marine, burrowing animals; 3 families and about
75 species.

* See "Synopsis of Astacoid and Thalassinoid Crustacea," by J. S. Kingsley, Am.
Nat., Vol. 33, p. 819, 1899.

DECAPODA 389

FAMILY CALLIANASSIDAE.

With the characters given above: about 7 American genera.

1. CALLIANASSA Leach. Cuticula soft and smooth; first 2 pairs of
periopods chelate, the first pair being large and very unequal in size ; eye
stalks flattened; third pair of maxillipeds flattened: about 20 species, 6
American.

C. stimpsoni S. I. Smith. Length 6 cm.;
small cheliped about half as long as the large
one; carapace smooth and glossy: from Long
Island Sound southwards, in burrows in the
mud between tide lines and in shallow water.

2. GEBIA Leach. Cuticula soft and smooth ; Fig. 622— oeUa
forward portion of cephalothorax compressed,

with a triangular, hairy rostrum; second pair of periopods not chelate;
third pair of maxillipeds pediform: 10 species, 2 American.

Cr. affinis Say (Fig. 622). Length 10 cm.: Long Island Sound to
South Carolina, living in burrows in the mud between tide lines and in
shallow water.

TRIBE 3. ASTACIDEA.

Lobsters and crayfish (Sig. 623). Body of moderate or large size
and with a thick shell; first antennae with 2 flagella, second either with a
scale or with none and much longer than the first; no longitudinal
sutures, but usually a transverse cervical suture in the carapace: 4
families and about 150 species.

Key to the families of Astacidea here described :

di Antennal scale and cheliped present.

6X Animals marine 1. NEPHROPSIDAE

52 Animals in fresh water 2, ASTACIDAE

aa Antennal scale and cheliped absent 3. PALINUHTDAE

FAMILY 1. NEPHEOPSIDAE.

Lobsters. Body of large size; rostrum dentate along the lateral
margins; first 3 pairs of periopods chelate, the first pair very large,
forming the pinching claws: 3 genera.

HOMARTJS Milne-Edwards. Rostrum with 3 teeth on each side; sec-
ond antennae with a small scale; eyes round: 2 species.

H. americanus* M.-Ed. American lobster. Length up to 60 cm.;
greatest weight 13 kg. or over 28 pounds; length of the average adult
lobster 25 cm.; average weight less than a kg. or about one and three-
quarters or two pounds; color usually dark green with darker spots and

* See "The American Lobster," etc., by F. H. Herrick, Bull. U. S. Fish. Com. for
1895. "Natural History of the American Lobster," by same, Bull. Bureau Fish., Vol.
29, p. 149, 1909.

390

CEUSTACEA

3rellowish underneath: Atlantic coast from Labrador to North Carolina,
in shallow water in summer and in deeper water in winter. Lobsters are
caught mostly off the coast of Canada and the New England states and

are our most important
food crustacean. The an-
nual catch has amounted
to over 100,000,000 in
some years but is now
much less.

FAMILY 2. ASTACIDAE.*

Crayfish. Body not so
large as in previous fam-
ily; rostrum without lat-
eral teeth: several genera
and over 100 species; in
fresh water.

Key to the genera of
Astacidae here described:

ox Pacific slope crayfish.

1. ASTACUS

az Atlantic slope and
Mississippi valley
crayfish. 2. CAMBABUS

Fig. 623 — A, diagram of a crayfish showing
arrangement of internal organs (McMurrich) ; B,
diagram of cross section of the cephalothorax
showing gill chamber ; C, interior of gill chamber
of Astacus, the outer wall having been removed
(Siissw. F. Deut.). 1, pleurobranch ; 2, upper
arthobranch ; 3, lower arthrobranch ; 4, podo-
branch ; 5, gill chamber ; 6, pleurobranch of the
last thoracic somite; 7, last periopod ; 8, gills;

,VH- t3\JL114.|,cr t I9 UM9» fc/CJ. IV/i/^VJ, , O, ^A4A0 ,

9, first periopod ; 10, mouth ; 11, stomach ; 12,
liver ; 13, heart ; 14, gonad ; 15, dorsal artery ;
1C, intestine ; 17, anus ; 18, ventral artery ; 19,
nerve chord ; 20, kidney.

1. ASTACUS Fabricius.
A pair of gills (pleuro-
branchs) on the last tho-
racic somite (Fig. 623,
C, 6), and 18 pairs in all: about 15 species, 5 on the Pacific slope, the
remainder in Europe and Asia.

A. nigrescens Stimpson. Chelae naked on outer face; margins of
rostrum denticulate; length 10 cm.; color dark greenish: San Francisco
to Alaska, near the coast; used for food.

2. CAMBARUS t Erichson. Common American crayfish (Fig. 623).

* See "Monograph of the North American Astacidae," by H. A. Hagen, Mem. Mus.
Comp. Zool., Vel. 3, 1870. "The Crayfish," by T. H. Huxley, 1881. "A Revision of
the Astacidae," by W. Faxon, Mem. Mus. Comp. Zool., Vol. 10, 1885. "Observations
on the Astacidae," etc., by W. Faxon, Proc. U. S. Nat. Mus., Vol. 20, p. 643, 1898.
"Synopsis of the Astacidae of North America," by W. P. Hay, Am. Nat., Vol. 33, p.
957, 1899. "The Young of the Crayfish Astacus and Cambarus," by E. A. Andrews,
Smithsonian Contributions to Knowledge, Vol. 35, p. 1, 1907.

t See "Ecological Catalogue of the Crayfishes Belonging to the Genus Cambarus,"
by J. Arthur Harris, Kansas Univ. Sci. Bull., Vol. 2, p. 51, 1903. "The Crawfishes
of the State of Pennsylvania," by A. E. Ortmann, Memoirs of the Carnegie Museum,
Vol. 2, p. 343, 1906. "Breeding Habits of the Crayfish," by E. A. Andrews, Am. Nat.,
Vol. 38, p. 165, 1904.

DECAPODA

391

Fig. 624 — The anterior abdominal appendage
(male) in Cambarus (Ortmann). A, O. pro-
pinquus; B, C. Umosus; C, C. bartoni; D,
C. diogenes.

No gills on the last thoracic somite and 17 pairs in all; first pair of
swimmerets bifid and often hooked at the apex in the male: about 70
species, all in North America
and east of the Rocky Moun-
tains. The animals live in
streams, lakes, and swamps,
resting under stones or in
burrows or among aquatic

vegetation near the surface; A g C

a few species are terrestrial,
living in burrows. Crayfishes
are omnivorous feeders, eat-
ing decaying animal and plant substances, but also living animals and
plants. Spawning occurs in the springtime and pairing in the fall in the

case of C. diogenes and C. Umosus
and others, but C. bartoni and others
probably pair and spawn the year
round. The eggs are carried by the
mother attached to her abdominal
legs until they hatch; the young ani-
mals when born have the form of the
parents and live for a while with the
mother, holding on to her abdominal
legs with their claws. Crayfishes are
used for food in New York and other
large cities.

C. bartoni* (Fabricius) (Fig. 624,
C). First pair of abdominal append-
ages of the male terminated with 2
strongly recurved tips; length 8 cm.;
the eastern specimens have a short
quadrangular rostrum; in the western
specimens the rostrum tends to be
elongate; body with few or no hairs;
carapace depressed: North America,
almost to the Mississippi, but espe-
cially along the Atlantic slope, usu-
ally in clear, small streams, but also

occasionally in muddy ones where it may burrow; one of our most
widely distributed and commonest crayfish.

Fig. 625 — Cambarus pellucidus
(Kingsley). 1, first antenna; 2,
second antenna ; 3, antennal scale ;
4, periopods ; 5, carapace ; 6, abdo-
men ; 7, uropod ; 8, telson ; 9, rostrum.

* See "Notes on the Habits of Certain Crayfish," by C. C. Abbott, Am. Nat, Vol.
7, p. 80, 1873.

392 CEUSTACEA

C. limosus (Rafinesque) (C. affinis Say) (Fig. 624, B). First pair of
abdominal appendages of the male terminated with 2 short, straight, diver-
gent tips; length 10 cm.; body hairy all over; sides of carapace spiny;
rostrum broad with parallel sides: eastern North America, not west
of the Alleghenies; common in the larger rivers, usually does not
burrow; the crayfish which is most commonly sent to the New York
markets.

C. pellucidus (Tellkampf) (Fig. 625). First pair of abdominal
appendages clavate, the outer part being truncate and toothed; eyes
atrophied; length 9 cm.: in caves in Indiana and Kentucky.

C. diogenes Girard (Fig. 624, D). First pair of abdominal appen-
dages in male terminate with 2 strongly recurved tips; rostrum rather
slender ; length 8 cm. : widely distributed and often common in the entire
country east of the Rocky Mountains ; preeminently a burrowing species,
being found in swamps and meadows often far from a stream; the bur-
rows are from 1 to 3 feet deep, with an enlargement at the bottom filled
with water; often with a chimney to the height of several inches over
the top.

C. virilis Hagen. First pair of abdominal appendages in male acute,
tapering, divergent; length 8 cm.: common in central states, in large
rivers and lakes.

0. propinquus Girard (Fig. 624, A). First pair of abdominal appen-
dages in male terminating in 2 elongate straight convergent tips; length
7 cm. ; rostrum with a median ridge : common throughout the central part
of the country, especially in large rivers and lakes.

FAMILY 3. PALINUEIDAE.

Spiny lobsters. Body of large size; antennal scale absent; none of
the periopods chelate: several genera.

PANTILIEUS Gray. Rostrum absent ; flagella of antennae long : several
species.

P. argus (Latreille). Florida crayfish. First pair of antennae with
a very long basal joint; body 20 to 40 cm. long; color violet, red, and
brown : common on coral reefs off the Florida coast ; an important article
of food.

TRIBE 4. ANOMURA.

Last pair of thoracic legs reduced in size and extend backwards and
upwards ; a swimming fin usually not developed : 2 families, both marine.
Key to the families of Anomura:

Oi Animals burrow in the sand 1. HIPPIDAE

oa Animals live in snail shells ; hermit crabs 2. PAGURIDAE

DECAPODA

393

Fig. 626 ,
Hippa talpoida
(Verrili).

FAMILY 1. HIPPIDAE.

Cephalothorax cylindrical, with the abdomen bent under it; telson
triangular and elongate; first pair of periopods not chelate: 3 genera and
about 20 species, which burrow in the sand.

HIPPA Fabricius. Second antennae long and fringed, with long hairs
on its hinder surface; eye stalk very long: 2 species, 1 American.

H. talpoida Say. The sand bug (Fig. 626).
Length 25 mm.; color whitish tinged with purple on
the back: Cape Cod to Florida; Pacific coast; very
common on sand bottoms and beaches, in which it
burrows with great rapidity.

FAMILY 2. PAGUEIDAE.

Hermit crabs. Cephalothorax flattened, and with
a hard shell; abdomen usually asymmetrical, elon-
gate, and soft ; eye stalks long ; first pair of periopods
large and chelate, last pair reduced in size and extend-
ing backwards and upwards, abdominal appendages rudimentary or
wanting, the last pair used to hold the animal in the snail shell in which
it lives. Allied to the hermit crabs is one of the most remarkable terrestrial
decopod crustaceans, Birgus latro, the palm crab of the Pacific. It lives in
holes in the ground and seldom goes into the water, but breathes air, the gill
chambers being converted by the presence of a network of blood capil-
laries into lungs, while the gills are
very small. Its food consists of cocoa-
nuts, which, however, it does not climb
the trees to get, as it is popularly
supposed to do. The family contains
about 20 genera.

PAGTJKUS Fabricius. First pair of
antennae short, second pair long; right
claw usually the larger : the animal
lives in the empty shell of some marine
snail which it carries about with it, and
as it increases in size changes for a
larger one; the shell is frequently more or less covered with colonies of
a hydroid, Hydractinia echinata, with which it lives in commensalism,
the hydroid enlarging the shell by building up its free edge and thus
saving the crab the necessity of changing its abode; over 100 species.
P. longicarpus Say. Small hermit crab. Chelae smooth and elon-
gate: very common from Maine to South Carolina, usually inhabiting the
shells of small snails in rock pools and shallow water along the beach.

Fig. 627 — Pagurus pollicaris, out of
its shell (Paulraeier).

394 CRUSTACEA

P. pollicaris Say (Fig. 627). Large or warty hermit crab. Chelae
covered with tubercles, and very wide and stout, and used by the animal
to close the opening of the shell: Maine to Florida, usually inhabiting
the shells of Fulgur, Natica, or other large snails in deeper water along
the shores.

SUBORDER 2. BRACHYURA.

Crabs. Cephalothorax short and broad, with the small abdomen
bent under it; abdomen of the male very narrow, with rudimentary legs
and fitting into a groove of the ventral surface of the cephalothorax ;
abdomen of the female broad, with 4 pairs of well-developed biramose
legs to which the eggs are attached; antennae very short and often foot-
like; third pair of maxillipeds flat and plate-like and covering the other
mouth parts ; the 5 pairs of periopods well developed, the first pair form-
ing the large pinching claws ; the abdominal legs much reduced, from 1 to

4 pairs being present; no
uropods present; young usu-
ally born in the zooea stage
and pass through the mega-
lopa stage before reaching
maturity (Fig. 628).

The crabs are the high-
est crustaceans. They occur
mostly in the sea, living on
or near the bottom, from tide
Fig. 628— Larvae^cmhJClaus). A, zooea ; lineg to yery great depths.

Some, however, like the blue

crab, swim very well and rapidly and are frequently seen near the
surface. Some species, like the fiddler crabs and the sand crabs, live
near the high-water line or above it and have become to a greater or
less degree terrestrial animals. They run about rapidly over the sand,
in which they dig deep burrows, and their gills and gill chamber are
especially adapted to the absorption and retention of moisture from
the damp sand. Still other crabs, as those belonging to the Gecarci-
nidae, the land crabs which are often distinguished by their large
size, are found habitually far from the water, to which they return period-
ically to deposit their eggs. Cardisoma guarihumi, the common land crab
of the "West Indies and Bermuda, occasionally makes its appearance in
Texas. The crabs of the family Thelphusidae live exclusively in fresh
water, the best-known representative being ThelpTiusa fluviatilis, the com-
mon fresh-water crab of southern Europe. The suborder contains 4
divisions.

DECAPODA 395

Key to the divisions of Bracliyura here described:

01 Carapace more or less triangular, being narrow in front 1. OXYBHYNCHA

02 Carapace more or less circular, elliptical or rectangular, with a wide-

arched or straight front margin.

&! Carapace elliptical, with an arched front 2. CYCLOMETOPA

62 Carapace rectangular, with a straight front margin 3. CATOMETOPA

DIVISION 1. OXYRHYNCHA.*

Carapace usually narrow and triangular in front and broad and
routided behind; 9 pairs of gills; first antennae longitudinally folded:

3 families.

FAMILY MAIIDAE.

Carapace narrow in front, rounded and broad in the middle, taper-
ing anteriorly to the prominent rostrum, which may be bifurcate: about
34 American genera, all marine and littoral and occurring principally in
southern waters; some of the species have the habit of concealing them-
selves by placing on their backs with their pincers, algae, sponges, etc.,
which often grow there.

1. LIBINIA Leach. Spider crabs. Eyes can be retracted into orbits,
which conceal them; rostrum bifurcate; body covered with a dense
growth of chitinous hairs which give it a furry appearance; it may also
have growing on it hydroids, algae, worm

tubes, etc., which tend to conceal it : 6 species.

L. emarginataf Leach (Fig. 629). Cara-
pace evenly rounded behind and with
spines on the back, 9 of these being median
in position; legs long, the chelipeds in the
male being very long; length of carapace 7
cm.; breadth 6 cm.: Atlantic coast from
Maine to Florida, very common on mud
flats and oyster beds.

L. dubia Milne-Edwards. Like the above, but with fewer spines on
the back, 6 of which are median: Cape Cod to Florida; less common than
L. emarginata.

2. HYAS Leach. Carapace more or less triangular; rostrum bifur-
cate, the 2 branches converging, eyes in orbits but not completely con-
cealed: 3 species.

H. coarctatus Leach. Toad crab. Lateral edges of carapace dilated

* See "Catalogue of the Crabs," etc., by Mary J. Rathbun, Proc. U. S. Nat. Mus.,
Vol. 15, p. 231, 1892 ; also Proc. U. S. Nat. Mus., Vol. 16, p. 63, 1893. "Synopsis of
the Oxyrhynchous and Oxystomatous Crabs of North America," by Mary J. Rathbun,
Am. Nat., Vol. 34, 1900.

t See "On the Anatomy of Libinia emarginata," by E. A. Andrews, Trans. Conn.
Acad., Vol. 6, p. 99, 1884.

396

CRUSTACEA

anteriorly; length of carapace 8 cm.; width 6.4 cm.: Greenland to Vir-
ginia; Europe; North Pacific; in 5 to 1,000 fathoms.

3. PELIA Bell. Carapace triangular, and much longer than broad;
surface smooth; eye stalk in an orbit but not completely concealed: 2
American species.

P. mutica (Gibbes). Small spider crabs. Claw of male with nearly
parallel sides and with edges which meet only at the tip: Cape Cod to
Florida and the Gulf of Mexico, from low- water mark to 15 fathoms.

DIVISION 2. CYCLOMETOPA.*

Carapace more or less circular or elliptical in form and usually
broader than long, the front forming a regular arch, and without a
distinct rostrum; 9 pairs of gills present: 6 families.

Key to the families of Cyclometopa here described :

ct First antennae folded longitudinally or nearly so 1. CANCKIDAE

«3 First antennae folded transversely or obliquely.

6t Last pair of legs not flattened for swimming 2. PILUMNIDAE

62 Last pair of legs flattened for swimming 3. POBTUNIDAE

FAMILY 1. CANCEIDAE.

Carapace usually broader than long and with very short rostrum
or none at all; anterior margin arched and serrate; last pair of legs
pointed at the end: about 4 genera.

CANCER L. Carapace flattened, and more or less elliptical in shape ;

the outer maxillipeds completely cover
the other mouth parts: 11 American
species, 2 on the Atlantic coast.

C. irroratus Say. Rock crab (Fig.
630). Anterior margin of carapace
with 9 blunt teeth on each side; length
of carapace 7 cm.; breadth 10 cm.;
color yellowish, thickly spotted with
small reddish dots: Labrador to South
Carolina; common among rocks and
in the sand, in which it may lie buried,

from low water to 300 fathoms ; the commonest crab on the New England
coast, where it is occasionally used for food.

C. borealis Stimpson. The northern or Jonah crab. Similar to the
preceding but larger, with a more convex and much rougher carapace;
color brick red : Labrador to Connecticut, often common among the rocks
in exposed places, not living under the rocks or in the sandy or muddy
bays.

* See "Synopsis of the Cyclometopous or Cancroid Crabs of North America," by
Mary J. Rathbun, Am. Nat., Vol. 34, 1900.

Fig. 630 — Cancer irroratus
(Rathbun).

DECAPODA 397

0. magister Dana. The edible crab of California. Carapace 12
cm. long and 15 cm. wide, with 9 short spines on each side of the anterior
margin; color reddish-brown: common below low-water mark on the
entire Pacific coast, where it is used for food.

FAMILY 2. PILUMNIDAE.

Small dull-colored crabs with the first antennae folded transversely
or obliquely, with a nearly round cephalothorax and without swimming
periopods: about 15 American genera, mostly southern.

PANOPEUS* Milne-Edwards. Mud crabs. Carapace slightly broader
than long : small, inconspicuous crabs which live on muddy bottoms along
the shore, often on oyster beds in brackish water, or even in fresh water ;
about 14 American species.

P. (Neopanopeus M.-Ed.) sayi S. I. Smith (Fig. 631). Carapace
somewhat convex, with a dentate anterior border; male abdomen with
the terminal segment triangular and somewhat broader than long;

Fig. 631 Fig. 632 Fig. 633

Fig. 631 — Panopeus sayi (Paulmeier). A, dorsal aspect; B, male abdomen.
Fig. 682 — Panopeus depressus — male abdomen (Paulmeier). Fig. 633 — Panopeus
herbsti — the large claw (Benedict).

length of carapace 17 mm. ; breadth 22 mm. ; color dark and dull : Massa-
chusetts to Florida; common.

P. (Eurypanopeus M.-Ed.) depressus Smith (Fig. 632). Like
P. sayi but with a flatter carapace and with a terminal abdominal seg-
ment in the male which forms an equilateral triangle, with arched sides;
length of carapace 14 mm. ; breadth 19 mm. : Cape Cod to Florida.

P. herbsti M.-Ed. (Fig. 633). Carapace with a dentate anterior
border and with a tubercle just beneath the first tooth; the larger claw
with a stout tubercle at the base of the movable segment; terminal
abdominal segment in male rounded ; length of carapace 40 mm. ; breadth
60 mm. : Long Island Sound to Florida ; near high- water mark.

FAMILY 3. POBTUNIDAE.

Swimming crabs. Carapace broader than long and with a well-
defined serrate, anterior margin; the last pair of periopods broad and

* See "The Genus Panopeus," by James E. Benedict and Mary J. Rathbun, Proc.
U. S. Nat. Mus., Vol. 14, p. 355, 1891.

398

CRUSTACEA

flattened at the end, and except in Carcinides m&nas not pointed, forming
effective paddles: 7 American species.

1. CALLINECTES* Stimpson. Carapace about twice as broad as long,
the anterior margin forming a serrated arch, at each end of which is a
long, sharp spine: about 4 species on the coast of the southern states.

C. sapidns Rathbun (C. hasta-
tus Say). Blue or edible crab
(Fig. 634). Length of carapace 7
cm.; breadth 13 cm.; color dark
green ; feet blue : Cape Cod to Lou-
isiana, common on muddy bottoms
in shallow, brackish or even fresh
water, often swimming among sea-
weed or near the surface; next to
Fig. 634— Caliinectes sapidus (Rathbun). the lobster our most important

food crustacean.

2. OVALIPES Rathbun (Platyonichus Latreille). Carapace not very
broad, being almost round, with 5 acute teeth on each side of the
anterior margin; 1 species.

O. ocellatus (Herbst). Lady crab (Fig. 635). Length of carapace
5 cm.; breadth 6 cm.; color light with red spots: Cape Cod to the Gulf
of Mexico, on sand beaches; is used for food in the South.

Fig. 635 Fig. 636

Fig. 635 — Ovalipes ocellatus (Rathbun). Fig. 636 — Carcinides mcenas (Rathbun).

3. CARCINIDES Rathbun (Carcinus Leach). Carapace slightly
broader than long ; chelipeds rather short ; last pair of thoracic feet flat-
tened but with pointed tips: 1 species.

C. maenas (L.). Green crab (Fig. 636). Carapace with 5 large,
acute teeth on the forward margin on each side; length 4 cm.; breadth
5 cm.; color green, mottled with yellow: Cape Cod to New Jersey;
Europe, where it is used for food; among the rocks in shallow water;
breeding season in spring.

* See "The Genus Callinectes," by Mary J. Rathbun, Proc. U. S. Nat. Mus., Vol.
18, p. 349, 1895.

DECAPODA 399

DIVISION 3. CATOMETOPA.*

Carapace more or less rectangular, with a wide, straight ante-
rior margin and a straight but narrower hinder margin; no rostrum pres-
ent: 4 families, including the land and strand crabs, which are among
the most active and intelligent crabs.

Key to the families of Catometopa here described:

«! Carapace soft and membranous; in oyster or mussel shells. 1. PINNOTHERIDAE
«3 Carapace hard and firm 2. OCYPODIDAE

FAMILY 1. PINNOTHEBIDAE.

Carapace nearly circular and more or less membranous; eye stalks
very small: small crabs, the females of which live in the mantle cavity
of certain pelecypods or in annelid tubes, the males being
f ree- swimming ; 1 genus.

PINNOTHERES Latreille. With the characters of the
family: several species.

P. ostreum Say. Oyster crab. Surface of body
smooth and shiny; length and breadth of carapace about
5 mm.: in the mantle cavity of the oyster.

P. maculatus Say. Mussel crab (Fig. 637). Surface hairy; length
and breadth about 8 mm. : in the mantle cavity of Mytilus edulis and other
bivalves, from Cape Cod to South Carolina.

FAMILY 2. OCYPODIDAE.

Carapace broad anteriorly and more or less quadrangular; eye stalks
long, each lying in an elongated groove-like orbit: 6 American genera.

1. OCYPODEf Fabricius. Carapace square in shape, with distinct
lateral margins ; chelipeds small, somewhat unequal ; other periopods flat,
with pointed tips; eye stalks stout: 1 American species.

0. albicanst Bosc (0. arenaria Say). Sand crab. Length of carapace
30 mm. ; breadth 35 mm. ; chelipeds of nearly the same size in both sexes ;
claw with serrated margins : New Jersey to Florida and southwards, living
in deep burrows above high- water mark; a very active crab which has
become a terrestrial animal.

2. UCA§ Leach (Gelasimus Latreille). Fiddler crabs. Chelipeds of
male of very unequal size, one, usually the right, being enormously devel-

* See "The Catometopous or Grapsoid Crabs of North America," by Mary J.
Rathbun, Am. Nat., Vol. 34, p. 583, 1900.

t See '.'Carcinological Notes, No. Ill, Revision of the Genus Ocypoda," by J. S.
Kingsley, Proc. Acad. Nat. Sci., Phil., for 1880, p. 179.

t See "Habits, Reactions, and Associations in Ocypoda arenaria," by R. P.
Cowles, Monograph No. 103, Cam. Inst. of Wash., 1908.

§ See "Carcinological Notes, No. 11, Revision of the Gelasimi," by J. S. Kingsley,
Proc. Acad. Nat. Sci., Phila., for 1880, p. 135.

400 ARACHNOIDEA

oped and carried across the front of the body; eye stalks very long and
slender; color light brown, mottled with purple and dark brown: small,
active crabs, living in burrows, often a foot or two deep, in salt marshes
and on mud and sand flats ; they are frequently seen in large droves, and
have the habit of slowly waving the large claw back and forth, probably
a threatening attitude; numerous species; cos-
mopolitan; about 7 American species.

U. pugnax (S. I. Smith). Inner surface of
large claw with an oblique ridge, beneath which
are granules; length of carapace 15 mm.; width

Plg' (P&u\£eilrrinaX 23 mm': Cap6 C°d tO Florida> common in salt
marshes.

U. minax (Le Conte) (Fig. 638). Legs with red patches at the
articulations; large claws with an oblique ridge on the inner surface;
length of carapace 25 mm.; width 38 mm.: Cape Cod to Florida; the
largest of the fiddlers, common in salt marshes, usually farther from
the sea than the other species, being frequently where the water is
fresh.

U. pugilator (Bosc). Length of carapace 15 mm.; width 21 mm.;
inner surface of large claw without oblique ridge : Cape Cod to Florida,
on sandy or muddy beaches near high-water mark.

CLASS 2. ARACHNOIDEA.

Arthropods without antennae, in which the body is usually made
up of two divisions, the cephalothorax and the abdomen, the former rep-
resenting the fused head and thorax and bearing six pairs of appendages,
and the latter being in most cases without appendages. The class con-
tains 2 subclasses.

Key to the subclasses of Arachnoidea:

ot Marine arachnoids of large size, with appendages bearing gills on the

abdomen, and a long spike-like telson 1. XIPHOSUBA

«a Mostly terrestrial arachnoids without abdominal appendages. .2. ARACHNIDA

SUBCLASS 1. XIPHOSURA.*

King or horseshoe crabs. Large crab-like arachnoids, in which the
body consists of a cephalothorax, an abdomen, and a long spike-like tel-
son or tail. The cephalothorax is horseshoe-shaped and unsegmented
and with an arched dorsal surface, in the center of the ventral surface
of which is the mouth. Six pairs of elongate appendages surround the
mouth, the anterior five of which are chelate, the sixth pair terminating

* See "Xiphosura," Camb. Nat. Hist., Vol. 4. p. 259, 19Q9.

XIPHOSURA 401

with a number of movable projections called the pushers, because they
are used by the animal in pushing itself through the sand and mud. The
first pair lie in front of the mouth, and are called the mandibles or
clielieerae : they are much smaller than the others, but have the same
shape. The basal joints of the remaining five pairs of legs are spiny
and assist in chewing the food. The abdomen bears six pairs of appen-
dages, none of which are leg-like. The first pair are called the operculum
and form together a broad plate which falls over and covers the remain-
ing five pairs; these are also plate-like and bear on their hinder surfaces
numerous thin gills. The males are smaller than the females and differ
from them in the structure of the second pair of appendages, the claw of
which is a thickened structure, of use in holding on to the shell of the
female while pairing. The paired genital openings are at the base of the
operculum. The telson may be as long as the rest of the body.

The dorsal surface of the cephalothorax bears two large lateral com-
posite eyes and a pair of small median ones. The dorsal surface of the
abdomen is flattened and bears a row of movable spines on each lateral
edge. The internal anatomy is essentially arachnid in character.*

The king crab lives in shallow water along the shore, where it bur-
rows in the sand and mud and eats worms and other small animals. It
comes to sandy beaches in the early summer to breed, and lays its eggs
in depressions it makes in the sand. The embryo as it emerges from the
egg has a resemblance to a trilobite and lacks the spine-like telson and
the abdominal appendages. The animals, although of large size, have
little economic importance. They are, however, sometimes fed to chick-
ens and pigs.

History.— T?he American Limulus was first made known in 1590 by
Thomas Harriot in his description of the animals and plants of Virginia.
The Asiatic species became known during the 17th century, the dried shells
having frequently been brought to Europe as curiosities. Until quite
recently zoologists have placed Limulus among the crustaceans. Latreille,
however, in 1808 called attention to its peculiar structure and created for
it the separate order Xiphosura^and StrJajusJlimildifiim-,m 1829 empha-
sized its resemblance "toTarachnids. This idea, however, gained ground
very slowly, although Huxley and von Beneden both spoke in favor of
it, and it was not until after Lankester's demonstration in 1881 that
Limulus was finally accepted as an arachnid. f Another question of rela-
tionship with which Limulus has to do is whether the primitive arachnid

* See "The Embryology of Limulus," by J. S. Kingsley, Jour. Morph., Vol. 7, p.
35, and Vol. 8, p. 195, 1S92-3. "Studies on Limulus," by W. Patten and W. A. Reden-
baugh, Jour. Morph., Vol. 16, p. 1 and p. 91, 1900.

t See "Limulus an Arachnid," by E. R. Lankester, Quart. Jour, Mic. Sci., Vol,
21, 1881,

402

AEACHNIDA

group from which it sprang is allied to the vertebrates and thus may be the
ancestor of this important class, as is maintained by Patten and others.*

The subclass contains the single genus Limulus. A few years ago,
however, a new classification was proposed subdividing this genus into
three, which were grouped in two subfamilies: this classification has not
been generally adopted.

LIMULUS 0. F. Miiller. With the characters mentioned: 5 species,
of which 4 inhabit the eastern coast of Asia and its islands.

-J 3"

Fig. 639 — Limulus
polyphemus (Ship-
ley). A, dorsal as-
Apect; B, ventral
aspect. 1, median
eyes ; 2, lateral eyes ;
3, cephalothorax ; 4, abdomen ;
5, telson ; 6, mandibles ; 7,
mouth ; 8 legs ; 9, chilaria ;
10, operculum ; 11, gills.

B

L. polyphemus (L.) (Fig. 639). Length up to 50 cm.; color dark
brown: eastern coast of North America from Nova Scotia to Florida;
common.

SUBCLASS 2. ARACHNIDA.

With rare exceptions air-breathing, terrestrial animals, without
antennae and with a body consisting of a cephalothorax and an abdomen.

External Structure.— The cephalothorax bears six pairs of appen-
dages, the mandibles or chelicerae, the pedipalps, and the four pairs of
walking legs. The abdomen is without locomotory appendages. The boun-
dary between these two body divisions is usually distinct, but in the mites it
is obliterated. In the spiders as well as the mites segmentation has
mostly disappeared and the body is short and compact. In contrast to
these forms are the scorpions, in which the body is long and vermiform,
with distinct segmentation. In the Solpugida the head is distinct from the
thorax and bears the first three pairs of appendages. The mandibles

* See "The Evolution of the Vertebrates and Their Kin," by W, Patten, 1912.

GENERAL DESCRIPTION 403

are short and end, on each side, either in a sharp, piercing claw, as in
spiders, or in a pincer-like claw, as in scorpions. The pedipalps are usually
sensory in function, but are prehensile organs in scorpions and many other
arachnids, and in the male spider have a copulatory function. The four
remaining pairs of appendages are locomotory and are usually long and
slender. The abdomen in the embryo has often rudimentary appendages,
the hinder three pairs of which in the spider become the spinnerets.

The cuticula of arachnids is often covered with cuticular hairs or
scales, which have often an important tactile function. The special
sense organs are not well developed. Eyes are generally present, but
they are ocelli and not the composite eyes so characteristic of other
arthropods.

Internal Structure (Fig. 654).— The digestive tract is often of com-
plex structure. Long diverticula may extend from the stomach towards
or into the legs, and a network of diverticula in the form of the so-called
liver usually occupies a large part of the abdomen; one or more pairs of
Malpighian or kidney tubules enter the rectum.

The respiratory organs are wanting in some mites and other minute
arachnids, but are usually present in the form of lungs and tracheae. The
lung is a ventral sac, usually near the anterior end of the abdomen and
opening to the outside through a pore called a spiracle, which contains
numerous leaf-like plates like the leaves of a book, in which the blood
circulates. The tracheae are air tubes reinforced on their inner surface
by a cuticular lining usually in the form of a spiral thread to keep them
from collapsing, which extend from spiracles throughout the body.
Scorpions and some of the larger spiders have only lungs; most spiders
have both lungs and tracheae; and mites and many other arachnids have
only tracheae.

Circulatory organs are wanting in many arachnids which lack a
special respiratory apparatus, but in most of them a tubular heart with
lateral valvular openings is present in the abdomen, from the ends of
which arteries extend into the surrounding organs. The Tardigrada are
hermaphroditic, but with this exception all arachnids are unisexual. The
paired gonads lie in the ventral portion of the abdomen and open to the
outside by paired ducts or by a single duct in the first or second abdomi-
nal somite. The sexes may often be distinguished by their external
characters, the male being smaller than the female and often provided
with special copulatory organs.

Most arachnids are oviparous, but the scorpions and a few others
bear their young alive. The young usually resemble the parents in
appearance, but in a few cases, as in the Linguatulida and the mites,
they go through a metamorphosis. The great majority of arachnids are

404

AEACHNIDA

predacious or parasitic animals, but a certain number of them, including
many mites, feed on plants. All of the Linguatulida and about half of
the species of mites are parasitic. Most arachnids are terrestrial but
the Tardigrada, Pygnogonida and two families of the Acarina are
aquatic.

History.— The name Araehnida originated with Lamarck in 1801,
who at that time separated these animals from the Insecta aptera of Lin-
naeus and his immediate followers. The subclass contains about 20,000
species grouped in 11 orders.

Key to the orders of Araehnida:

«! Abdomen distinctly segmented.
&! Animals not parasitic.

G! Long segmented postabdomen or segmented caudal filament (except the
Tarantulidae) present.

di Postabdomen with caudal sting present 1. SCOBPIONIDA

da Caudal filament (except the Tarantulidae).
e^ Animals minute; caudal filament with segmental bristles. .2. PALPIGRADI

62 Animals larger; caudal filament, when present, smooth 3. PEDIPALPI

c2 No postabdomen or caudal filament.
dt Head distinct from thorax, bearing first 3 pairs of

appendages 4. SOLPUGIDA

?! Pedipalps chelate and very long.

5. PSEUDOSCORPIONIDA

ea Pedipalps not chelate ; legs very long and slender.

6. PHALANGIIDA
62 Animals worm-like and internal parasites in

vertebrates 9. LINGUATULIDA

2 Abdomen not segmented.
&! Animals usually terrestrial.
Cj Cephalothorax distinctly separated from abdomen.

7. ARANEAE

c2 Cephalothorax and abdomen not distinct. . . .8. ACARINA
52 Animals aquatic.

Cj Animals microscopic 10. TARDIGRADI

c2 Animals marine and not microscopic ; legs very

long and slender 11. PYCNOGONIDA

ORDER 1. SCORPIONIDA.*

Fig. 640— Dia-
gram of the dor-
sal aspect of Cen-
trums (Banks).

1, cephalothorax ;

2, pre-abdomen ; 3,
postabdomen ; 4,
mandibles; 5,
pedipalps ; 6, lat-
eral eyes; 7,
median eyes ; 8,
spine ; 9, sting.

(Fig. 640.) Elongated arachnids with a short, un-
segmented cephalothorax and a long abdomen consisting
of 13 segments, of which the anterior 7 form the pre-
abdomen and are about of the same diameter as the
cephalothorax, and the posterior 6 form the much narrower, tail-like post-
abdomen, at the end of which is a poisonous sting; 3 to 6 pairs of eyes
usually present; mandibles short and chelate; pedipalps very long and

* See "Scorpiones und Pedipalpl," by K. Kraepelin, Das Tierreich, 1899. "Synop-
sis of the North American Scorpions, Solpugids, and Pedipalpi," by Nathan Banks,
Am. Nat, Vol. 34, p. 421, 1900.

SCOEP10NIDA 405

chelate; on the ventral surface the second abdominal segment bears a pair
of long comb-shaped appendages called the pectines, which probably aid in
the act of pairing, following which are 4 pairs of spiracles, each of which
opens into a lung sac; genital opening just in front of the pectines on
the first abdominal segment and protected by small paired plates, which
form the sternum; the young are born alive and are carried about for
a while by the mother : over 300 species, about 25 occurring in our south-
ern and western states, ranging as far north as Nebraska; they are
nocturnal animals and feed on insects and spiders which they often
kill with the sting.

Key to the families of Scorpionida here described:

G! Sternum broad, pentagonal ; usually no spine under the sting.

&! At base of terminal segment of last pair of legs at least 1 spur on inner

and 1 on outer side 1. VE.TOVIDAE

62 But 1 spur present, on outer side 2. SCORPIONIDAE

aa Sternum long, triangular; usually a spine under the sting. . .3. CENTBUBIDAE

FAMILY 1. VEJOVIDAE.

Three eyes on each side; terminal joint of legs with an inner and
outer spur at base; no spine under the sting: 8 genera and 18 species.

1. VEJOVIS Koch. Median lamella of each comb divided into at
least 8 small pieces; lower margin of the movable finger of mandible
without spines: 6 American species.

V. boreus (Girard). Hand strongly keeled; color yellowish or
greenish: Nebraska and westerly to Nevada and Idaho.

V. mexicanus Koch. Hand less distinctly keeled; color brown, not
spotted; legs reddish; length 8 cm.; number of teeth of comb 15 to 22:
Texas.

V. carolinus Koch. Color reddish-brown; legs yellow; length 34
mm. ; number of teeth of comb 13 or 14 : southern Atlantic states and into
Kansas and Texas; California.

2. HADRUEUS Thorell. Large, hairy scorpions with a large, dark
spur near the tip of the lower margin of the movable finger of the man-
dible : 2 species.

H. hirsutus (Wood). Color yellowish-red; length 7 cm.; number of
teeth of comb 25 to 40; legs compressed: California and Arizona.

FAMILY 2. SCORPIONIDAE.

Sternum pentagonal in shape; but 1 spur at the base of the last
tarsal joint, which is on the outer side ; usually no spur under the sting :
15 genera and about 88 species.

DIPLOCENTRTJS Peters. With a hump under the sting : 6 species, all
American.

406

ABACHNIDA

D. white! (Gervais). Color yellow or brown; terminal joint of foot
with a row of about 7 spines running up from the claw; teeth of comb
12 to 18; length 5 cm.: Texas to California.

FAMILY 3, CENTKUEIDAE.

Sternum small and triangular, the sharp end in front ; a spur on the
under side of the unmovable finger of the mandible : 4 genera and about
50 species, many American.

CENTRURUS Ehrenberg (Fig. 640). The oblique rows of teeth on
the finger of the pedipalp have on each side a parallel row of minute
teeth; under the sting may be a spine: 15 American species.

C. carolinianus (Beauvois). Color yellowish, with small spots, often
joined into 2 longitudinal stripes; length 7 cm.; teeth of comb, 19 to 25:
southern states.

ORDER 2. PALPIGRADL*

Minute arachnids with a segmented abdomen, from the hinder end
of which a long segmented caudal filament
with segmental bristles projects; mandible
long and chelate; pedipalps and the 4 pairs
of legs rather long and slender; no eyes;
cephalothorax of 3, abdomen of 11 segments :
1 genus with a few species, which have
been found in Italy, Siam, Paraguay, and
Texas.

K(ENENIA Grassi. With the characters
above mentioned: 2 American species.

K. wheelerif Riicker (Fig. 641). Length
with filament up to 2.5 mm.; color white;

3 pairs of eversible lung sacs on segments

4 to 6: under stones in moist places near
Fig. 641 — Kcenenia wheeleri

(Wheeler). Austin, Texas.

ORDER 3. PEDIPALPI.J

Cephalothorax separated by a constriction from the abdomen, which
is 11 or 12-jointed; last 3 pairs of legs used for walking; in the first

* See "Palpigradi und Solifugae," by K. Kraepelin, Das Tierreich, 1901.

t See "A Singular Arachnid," etc., by W. M. Wheeler, Am. Nat., Vol. 34, p. 837,
1900. "The Texas Kcenenia," by Augusta Riicker, Am. Nat., Vol. 35, p. 615, 1901.
"A New Kccnenia from Texas," by same, Q. J. M. S., Vol. 47, p. 401, 1903.

$ See "On the Pedipalpi of North America," by H. C. Wood, Jouf. Acad. Nat. Sci.,
Phila., Vol. 5, p. 357, 1S63. "Scorpiones und. Pedipalpi," by K. Kraepclin, Das Tier-
reich, 1899. "Synopsis of North America Pedipalpi," by N. Banks, Am. Nat., Vol. 34,
p. 421, 1900.

PEDIPALPI

407

pair the terminal portion very much elongated and forming a long,
many- jointed tactile flagellum; pedipalps thick and strong and, like the
mandibles, either chelate or not; 2 pairs of book lungs on the third and
fourth abdominal segments; 8 eyes usually present, 2 large ones in front
and 3 small ones on each side; genital pores paired and on the first
abdominal segment: predacious tropical animals, 5 species of which are
found along the southern border of this country; 3 families and about
60 species.

Key to the families of Pedipalpi here described :

01 Long filiform tail present 1. THELYPHONIDAE

02 No such tail 2. TARANTULIDAE

FAMILY 1. THELYPHONIDAE.

Whip scorpions. Body elongate; pedipalps chelate; 'abdomen 12-
jointed, the last 3 segments smaller than the others and bearing a long,
jointed terminal filament and also often om-
matoids, white ocellus-like spots: 10 genera and
about 40 species.

MASTIGOPROCTITS Pocock. Two ommatoids
present: 17 species.

M. giganteus (Lucas). Vinegar roan (Fig.
642). Length (with tail) 13 cm.; color dark
brown; tail with reddish hairs; animal has a
strong odor of vinegar : Florida to Arizona, often
common in dry sandy places; they are nocturnal
Fig. Q42—Ma8tigoproc- animals which are much feared, although they

tus giganteus

(Comstock). are not poisonous.

FAMILY 2. TARANTTJLIDAE.

Body broad, cephalothroax being broader than
the abdomen and joined with it by a slender waist;
pedipalp ends with a claw; abdomen 11-jointed and
without a terminal filament: 10 genera and about
18 species.

Tarantula Fabricius. Foot with a single claw;
front margin of celphalothorax either with short
teeth or smooth: 4 species, all American.

T. white! (Gervais) (Fig. 643). Front margin
of cephalothorax denticulate; inner margin of pedipalp with long
spines; color brown with a yellow margin; length 20 mm.: Texas to
California.

Fig. 643

Tarantula ichitei
(Banks).

408

ARACHNIDA

ORDER 4. SOLPUGIDA.* (SOLIFUGAE.)

Head region separated from the thorax and bearing very large
chelate mandibles, the leg-like pedipalps, and the first pair of legs, as well
as a pair of eyes; thorax consists of 3 distinct segments, each bearing a
pair of legs; abdomen 10-jointed; respiration by tracheae, the first pair
of spiracles being on the thorax, the other 3 pairs being on the abdomen;
genital pore in first abdominal segment : usually nocturnal animals which
live in sandy deserts in the warmer parts of the earth; 3 families with
about 165 species, a few of which are found in this country, chiefly in
the southwest; they are much feared, although not poisonous.

FAMILY SOLPUGIDAE.

Second and third pair of abdominal spiracles not covered with
denticulate plates: 21 genera and about 145 species.

EREMOBATES Banks (Datames Simon).
Anterior margin of head truncate; fourth
pair of legs without a terminal claw; dorsal
finger of mandible without teeth or spur:
about 18 species, all in America.

E. pallipes (Say). The movable seg-
ment of the mandibles in the male with 1
large and sometimes 1 very small tooth;
the inner side of the pedipalp of male
hairy and without bristles; length 13 mm.;
color light yellow: southern states west
of Mississippi, north into Kansas and

Fig. 64

Eremobatcs Jormi-
(Kingsley).

E. formidabilis (Simon) (Fig. 644).
Movable segment of the mandible slender and with 1 large and 2 small
teeth: California and Arizona.

ORDER 5. PSEUDOSCORPIONIDA.f

Small arachnids with an 11-jointed abdomen, with chelate mandibles,
the movable finger of which bears along its inner margin the comb-

* See "The Solpugidae of America," by J. D. Putnam, Proc. Davenport Acad.
Nat. Sci., Vol. 3, p. 1, 1882. "Synopsis of the North American Solpugida," by N.
Banks, Am. Nat., Vol. 34, p. 426, 1900. "Palpigradi und Solifugae," by K. Kraepelin.
Das Tierreich, 1901.

t See "Notes on North American Chernetidae," by N. Banks, Cand. Entom., Vol.
23, 1893. "Notes on the Pseudoscorpionidae," by N. Banks, Jour. N. Y. Entom.' Soc.,
Vol. 3, 1895. "Habits and Distributions of the Pseudoscorpionidae, principally
Chelanops oblongus, Say," by E. W. Berger, Ohio Nat., Vol. 6, p. 407, 1905. "A List
of the North American Pseudoscorpionida," by K. R. Coolidge, Psyche, Vol. 15, p.
108, 1908.

PSEUDOSCORPIONIDA 409

shaped serrula (Fig. 645, B), and with long scorpion-like pedipalps; legs
long, 5-jointed, and ending with 2 claws; eyes present or not; respiration
by tracheae, 2 pairs of spiracles being present on the second and third
abdominal segments ; genital pore in the second abdominal segment, in the
female surrounded by cement glands, the secretion of which serves to fasten
the eggs to the body of the mother ; silk glands open to the outside near the
tip of the movable finger of the mandible; the animals spin nests, in
which they spend the winter or can retire during a moult ; no poison glands
present: under the bark of trees, among moss or dead leaves, or in
houses, on old books, or furniture, where they eat mites and small insects;
occasionally they attach themselves for purposes of migration to insects;
they run rapidly forwards, backwards, or sideways; 3 families with 100
species.

Key to the families of Pseudoscorpionida here described:

<»! Cephalothorax with a transverse suture; two eyes or none usually

present 1. CHELIFEBIDAE

o, No such suture ; four eyes usually present 2. OBISIIDAE

FAMILY 1. CHELIFEKIDAE.

Spinneret on mandible long and tubular; serrula attached along its
whole length; 2 eyes or none present: 5 genera.

1. CHELIFER Geoffrey. Cephalothorax triangular, rounded in front
and divided by transverse sutures into 3 parts; 2 eyes present; man-
dibles small: several species.

C. cancroides (L.). Book scorpion (Fig. 645). Length 3 mm.; color
reddish-brown; dorsal abdominal plates divided by a median line; basal

Fig. 645 Fig. 646

Fig. 645 — Chelijer cancroides. A, dorsal aspect (Leunis) ; B, mandible (Comstock).
Fig. 646 — Chelanops oblongus (Berger).

portion of pincer thick, terminal finger curved: often found in houses
on old books, furniture, or clothing; cosmopolitan.

C. biseriatum Banks. Body 2.2 mm. long, pale yellowish in color,
with 2 rows of dark spots on the abdomen; pedipalps very slender; no
large granules on Cephalothorax : Florida ; Ohio ; Jamaica.

410 ARACHNIDA

C. muricatus Say. Body 2.5 mm. long and reddish-brown in color;
hand of pedipalp very much darker than the rest: eastern states, among
dead leaves.

2. CHELANOPS Nicolet (Chernes Menge). Similar to Chelifer but
without eyes: about 19 American species.

0. oblongus (Say) (Fig. 646). Body 3.5 mm. long, elongate and
elliptical in shape, being widest in the middle, reddish-brown in color,
being darker on the cephalothorax ; a double row of large dark spots
on the abdomen, from each of which a number of long bristles spring:
widely distributed over the eastern and central states; under stones
near low-water mark at Woods Hole.

C. tristis Banks. Body 2 mm. long, pale reddish-yellow in color
with soft parts and legs white; abdomen elliptical, the dark spots on
the dorsal plates being much nearer the median than the lateral line :
the seashore of Long Island.

C. sanborni Hagen. Body 2 mm. long, very broad, and reddish-
brown in color; pedipalps short and heavy with clavate hairs: eastern
states, under bark.

FAMILY 2. OBISIIDAE.

Spinneret a small knob; serrula attached only at the base; 4 eyes
usually present: 4 genera.

1. OBISIUM Leach. Cephalothorax rectangular and not narrower in
front; pedipalps short and stout; 4 eyes present; fingers curved: 6
species in America.

0. muscorum Leach. Body 2.5 mm. long, brownish in color : in moss.

2. CHTHONIUS Koch. Cephalothorax rectangular and wider in
front; mandibles large; fingers straight: about 5 American species.

C. pennsylvanicus Hagen. Length 1.9 mm.; color brownish, with
scattered silvery spots on the abdomen; legs white; pedipalps longer
than the body; 4 eyes, not close together: eastern United States.

ORDER 6. PHALANGIIDA.*

Harvestmen or daddy longlegs. Body short, ovoid in shape, with
an unsegmented cephalothorax which is joined with the 9-jointed ab-
domen without any constriction; mandibles chelate; pedipalps long and
leg-like, each ending with a claw; legs usually very long and slender, the
basal portion of the anterior pairs possessing chewing plates; the body

* See "On the Phalangeae of the United States," by H. C. Wood, Commun. Essex
Inst, Vol. 6, p. 10, 1868. "A Descriptive Catalogue of the Harvest Spiders (Phal-
angiidae) of Ohio," by C. M. Weed, Proc. U. S. Nat. Mus., Vol. 16, p. 543, 1893.
"Synopsis of North American Phalangida," by N. Banks, Am. Nat., Vol. 35, p. 669,
1901.

PHALANGIIDA

411

of the male somewhat smaller and with longer legs than the female;
a pair of simple eyes present, one being on each side of a tubercle rising
in the middle of the cephalothorax; genital opening between the last
pair of legs in a forward prolongation of the ventral plate of the first
abdominal segment from which also extends a long protrusible penis or
ovipositor (Fig. 648, 2) ; a pair of stink glands on the abdomen, which
often become active when the animal is handled ; respiration by tracheae,
usually a single pair of spiracles being present on the first abdominal
segment ; eggs laid in the ground or in other moist places in the summer
or autumn and the young, which are like the adults in appearance, usu-
ally hatch the following spring:
about 60 species in America,
grouped in 7 families ; animate more
or less nocturnal, probably feeding
principally on small insects, spiders,
and mites, but also occasionally on
decaying substances; they do not
spin a web or build a nest.

Key to the families of Phalan-
giida here described:

0! Last segment of pedipalp with
a terminal claw and longer
than the preceding one.

1. PHALANGIIDAE

a2 No such claw and the last seg-
ment much shorter than the
preceding one . 2. NEMASTOMATIDAE

Fig. 647 — A, dorsal view of a pha-
langid ; B, ventral view of a phalangid
(Banks). 1, mandibles; 2, pedipalps ;
3, logs ; 4, eye tubercle ; 5, abdomen ; t>,
cephalothorax ; 7, genital pore ; 8, for-
ward prolongation of abdomen; 9,
spiracle ; 10, anus.

FAMILY 1. PHALANGIIDAE. (FiG. 647.)

Body ovoid with a leathery integument; pedipalp ending with a
claw; legs long and slender, with a simple terminal
1 claw on each: about 15 American genera.

Key to the genera of Phalangiidae here de-
scribed :

tti Eye tubercle of enormous size 1. CADDO

a2 Eye tubercle of normal size .2. LIOBUNUM

&! Eye tubercle smooth.

62 Eye tubercle spinose 3. PHALANGIUM

Fig. 648 — Caddo agilis

(Comstock). 1, eye;

2, ovipositor.

1. CADDO Banks. Eye tubercle of enormous
size; 3 long spines on femur of pedipalp: one
species.

C. agilis Banks (Fig. 648). Body 3 mm. long, brown in color, with
2 pale stripes above: among dead leaves and moss.

412

ARACHNIDA

2. LIOBUNUM Koch. Anterior and lateral borders of cephalothorax
not spinose; eye tubercle rather small and smooth; legs usually very
long and slender: 16 American species.

L. vittatum (Say) (Fig. 649). Body reddish-
brown, with a distinct mid-dorsal stripe; pedipalps
and legs brown or black ; length about 9 mm. ; of pedi-
palps, 5 mm. long; length of legs, first, 42 mm., second,
90 mm., third, 43 mm., fourth,
61 mm.: eastern and central
America; common in fields
and woods.

L. politum Weed (Fig.
650). Body reddish-brown;
pedipalps light brown, legs
black; eye tubercle rather
prominent, with a row of small black projections over each eye; length
about 5 mm.; pedipalps 2.8 mm. long; length of legs, first, 25 mm.,
second, 51 mm., third, 26 mm., fourth, 36 mm. : eastern and central states,
in fields and woods; common.

L. grande (Say). Body blackish and tuberculate, 9 to 12 mm. long;
pedipalps 6 mm. long; length of legs, first, 20 mm., second, 35 mm., third,
21 mm., fourth, 28 mm. : eastern and central states.

Fig. 649— Liobunum vittatum (Weed).

Fig. 650

Fig. 651

Fig. 650 — Liobunum politum (Weed). A, dorsal aspect after the removal of the
legs; B, side view of the eye tubercle. Fig. 651 — Lioounum ventricosum (Weed).
A, dorsal aspect after the removal of the legs ; B, side view of the eye tubercle.

L. ventricosum (Wood) (Fig. 651). Body elongate; legs and body
cinnamon or yellowish-brown; length 7 to 10 mm.; length of legs, pedi-
palps, 5 mm., first, 33 mm., second, 64 mm., third, 33 mm., fourth, 48
mm.: eastern and central states; common.

3. PHALANGIUM L. Anterior and lateral borders of cephalothorax
spinose; eye tubercle with 2 series of spines: 2 species in America.

AEANEAE

413

P. cinereum Wood (Fig. 652). Body gray, sometimes brownish,
usually with a wide lenticular mid-dorsal marking, and about 8 mm.
long; pedipalps 4 mm. long; length of legs, first, 20
mm., second, 52 mm., third, 29 mm., fourth, 36 mm. :
northern America, on walls, etc., rarely in the open
field.

FAMILY 2. NEMASTOMATIDAE.

Pedipalps long and prominent, with last joint
much shorter than the preceding one and without a
claw: 3 genera.

PHLEGMACERA Packard. Mandibles directed
downwards and not forwards; fourth joint of pedi-
palp much thickened ; body somewhat compressed and
not spiny: 3 species.

P. cavicolens Pack. Body 4 mm. long and 2 mm.
wide; eyes large and prominent; eye tubercle very

low; a series of large

Fig. 652— Phalan-
gium cinereum
(Weed). A, dorsal
aspect after the re-
moval of the legs ;
B, eye tubercle.

transverse dark spots

on back; movable

finger of mandible

with about 24 setae: in caves and similar

places; eastern and central states.

ORDER 7. ARANEAE.* (ARANEIDA.)

Spiders (Fig. 653). Cephalothorax
and abdomen mostly
unsegmented and uni-
ted by a slender waist.
The body is often cov-
ered with hairs or
scales, and gray or
dark in color when the
animal lives on or near
the ground, but is
often brightly colored
when it lives on flowers, shrubs, or trees. Of the six pairs of appen-
dages the mandibles or chelicerae are the most anterior; they are two-

* See "Catalogue of the Described Araneae of Temperate North America," by Dr.
George Marx, Proc. U. S. Nat. Mus., Vol. 12, 18S9. "American Spiders," etc., by
Henry C. McCook, 1889-1893. "Histoire Naturelle des Araigne"es," by E. Simon, Paris,
1897-1904, 2nd Ed. "The Common Spiders of the United States," by James H.

Fig. 653 — A, diagram of the ventral aspect of a
spider; B, front of head (Emerton) ; C, palpal organ of
male (Warburton). 1, pedipalp ; 2, mandible; 3, max-
illa ; 4, labium ; 5, legs ; 6, sternum ; 7, epigynum ; 8,
lung spiracle ; 9, tracheal spiracle ; 10, spinnerets ; 11,
eyes.

414 AEACHNIDA

jointed, the terminal joint being a sharp claw, near the end of which is the
opening of a poison gland. The mandibles are usually directed downwards
so that the spider must strike when its prey is beneath it. The second
pair of appendages are the pedipalps or palpi, which are leg-like in form
and composed of six segments; the large and flattened basal segments
of these are called the maxillae or endites and extend forwards, forming
the principal jaws of the animals, being used to chew or squeeze the
food.

In the male the end of the pedipalp is enlarged and bears the

more or less complicated palpal organ by which sperm is conveyed to

the female in the act of pairing (Fig. 653, C). The four pairs of long

walking legs are seven- jointed. The tarsus or terminal joint of each leg

bears a pair of claws, the inner edge of each of which is toothed ; in many

spiders a third smaller claw is also present and in others a thick brush of

hairs. Between the maxillae is a plate called the labium or lip, and

between the base of the legs is the sternum. The abdomen bears at

its hinder end, just in front of the anus, usually 3 pairs of spinnerets,

which are modified legs (Fig. 655). At the end of each spinneret are

minute tubes which are the ends of the ducts of the silk glands; the

fluid silk coming out of these tubes unites to form a single strand, and

hardens on exposure to the air. In a few families a plate called the

cribellum lies in front of the spinnerets from which spinning tubes also

project; such spiders have a row or comb of stiff hairs on each of the

hind legs called the calamistrum (Fig. 655) by means of which a band of

silk may be spun. All the spinning tubes do not exude the same kind

of silk, but a variety of kinds is produced which are used for various

purposes, as for making the different parts of the web, nests, cocoons, etc.

Spiders are not well provided with special sense organs. The long

legs and the hairs usually covering the body are tactile organs, and in

most spiders eight simple eyes are present on the front portion of the

cephalothorax usually in two rows, enabling the spider to see a short

distance (Fig. 653, B).

The respiratory organs of spiders consist of two pairs of lungs in
the Tetrapneumones, which are situated in the forward part of the abdo-
men and open to the outside by slit-like spiracles on the ventral surface;
in the Dipneumones one pair of lungs is present and a pair of tracheae,
the latter opening in most cases through a single spiracle in front of
the spinnerets. Each of the lung spiracles is covered with an integu-

Emerton, 1902. "Families and Genera of the Araneida," by Nathan Banks, Am. Nat,
Vol. 34, p. 293, 1905. "Fauna of New England. A List of the Araneida," by Eliza-
beth B. Bryant, Bost. Soc. Nat. Hist., Occ. Papers, No. 7, 1908. "Catalogue of Neartic
Spiders," by N. Banks, Bull. No. 22, U. S. Nat. Mus., 1910. "The Spider Book," by
J. H. Comstock, 1912.

ARANEAE 415

mental fold, and between them is the genital pore which, in the
female, is covered by a plate, often complex in structure, called the
epigynum.

The arrangement of the internal organs of spiders will be seen in
the accompanying diagram (Fig. 654).

Spiders prey principally upon insects, but will usually kill and
devour any animal smaller than themselves, including their own kind.
The female not infrequently eats the smaller male when he approaches
her at pairing time. Spiders may be divided, as to their method of
taking their prey, into 2 groups: (1), the hunting spiders, which run
on the ground or on plants and spring upon their prey, usually from a
concealed retreat, and (2), cobweb spiders, which make webs to catch
flying insects. The hunting spiders often make nests of silk; the cob-
web spiders usually live in their webs or in nests near them.

The webs are of 4 kinds: (1), the very irregularly woven web of
the house spider Theridion tepidariorum and other Theridiidae (Fig. 664) ;
(2), the more or less
irregular web of the
Linyphiidae and some
other spiders, the most

important part of which

consists of a large, flat

or curved sheet held " j / ^ *&

down by threads in all

directions (Fig. 665) ; Fig. 654— Internal anatomy of a spider (Shipley).

/0\ xi .e , , £ 1, eyes; 2, poison gland; 3, mouth; 4, brain; 5,

(d), the tunnel webs Ot diverticulum of the stomach ; 6, lung; 7, genital pore;

,,.,., . , 8, silk glands; 9, anus; 10, spinnerets; 11, ovary;

the Agelemdae, consist- 12, kidney tubule; 13, intestine; 14, heart; 15, liver

* n , ^ -, ducts, the liver having been removed ; 16, sucking

ing of a flat sheet and stomach.

a funnel leading to a

retreat; (4) the round webs of the Epeiridae, composed of threads

radiating from a common center, with cross threads (Fig. 667).

Spiders lay spherical eggs which the female winds with silk into
a spherical or oblong mass called the cocoon; this the spider often
carries about for awhile in the mandibles or attached to the spinnerets,
and fastens in the web or to grass or other objects, or hides in her nest.
Some spiders construct burrows in the ground in which they deposit
their cocoons. Spiders live usually less than a year. Great numbers, the
adults of which die in the autumn on the approach of cold weather, pass
the winter in the form of eggs, while others lie torpid among leaves on the
ground and in other protected places. Spiders are born with the form
of the parent, but often differ from them at first very much in appear-
ance; they are also sexually dimorphic, the males being smaller than

416 ARACHN1DA

the females, possessing the palpal organ, and often being differently
marked.

Over 10,000 species are known, of which 1,300 belong in this country.
The order contains 2 suborders and about 26 families.

Key to the suborders of Araneae :

01 Two pairs of lungs ; usually 2 pairs of spinnerets ; claw of mandible

vertical in position 1. TETRAPNEUMONES

02 One pair of lungs ; 3 pairs of spinnerets ; claw of mandible horizontal in

position, working from the side, medially 2. DIPNEUMONES

SUBORDER 1. TETRAPNEUMONES.

Often large spiders with 2 pairs of lungs and 2 or 3 pairs of spin-
nerets; mandibles usually project more or less forwards, the claw of
which projects downwards instead of transversely; with 8 eyes set
closely together: tropical or subtropical spiders including the bird
spiders and trap-door spiders; 3 families.

FAMILY AVICULAEIIDAE.

Pedipalp arises near or at the tip of the maxilla, which is not dis-
tinct; the 4 lung spiracles covered by broad and often glistening folds:
40 American species.

PACHYLOMERUS* Ausserer. Trap-door spiders. Cephalothorax al-
most as broad as long; abdomen ovoid; spinnerets 4; eyes close together,
on low prominences, the lateral eyes being the largest; the extremities of
the 2 hinder pairs of legs much thickened: 8 American species, in the
southern states.

P. audonini (Lucas). Length 20 mm.; the anterior lateral eyes
the largest ; third joint of the third pair of legs very short and crooked ;
color glossy brown: North Carolina; the animal lives in a cylindrical
burrow in the ground lined with silk, the opening of which can be closed
by a circular door which works with a hinge.

SUBORDER 2. DIPNEUMONES

Spiders with 1 pair of lungs; tracheae also present which open to
the outside usually by a single spiracle; 3 pairs of spinnerets; mandibles
directed downwards, the claws projecting from the side towards the
median line: over 30 families.

* See "A New Trap-Door Spider," by G. F. Atkinson, Am. Nat., Vol. 20, p. 583,
1886.

AEANEAE

417

Key to the families of Dipneumones here described:
av With cribellum and calamistrurn (Fig. 655).

&! Eyes all dark-colored (diurnal) ; web usually regular 1. ULOBORIDAE

&2 Anterior median eyes dark, the other light-colored (nocturnal) ; web
irregular.

ct Lateral eyes near together 2. DICTYNIDAE

c2 All the eyes close together on an eminence 3. FILISTATIDAE

o2 Without cribellum and calamistrum.
&! Two terminal claws on the feet.

Cj Six eyes ; 4 spiracles ; ground spiders 4. DYSDEBIDAK

C2 Eight eyes present.
di Eyes usually in 2 rows.
€1 First 2 pairs of legs not noticeably longer than the others.

/x Fore spinnerets widely separated ; ground spiders 5. DRASSIDAE

/2 Fore spinnerets contiguous ; ground spiders 11. CLUBIONIDAE

e2 First 2 pairs of legs much longer than the others ; crab spiders.

10. THOMISIDAE

da Eyes in 3 rows, the middle row being much smaller than the others.
62 Three terminal claws on the last 3 pairs of feet. 15- ATTIDAE

Cj Legs very long, being over 4 times the length of the body 6. PHOLCIDAE

c2 Legs not so long.
dl Eyes in 2 rows.

61 Hinder part of spinnerets not very long.

/! A comb of serrate bristles on the hind foot ; abdomen often globose.
/, No such comb. 7- THERIDIIDAE

&! Basal segment of mandible with row of teeth on its outer surface ;

small spiders with irregular webs 8. LINYPHIIDAE

ff2 No such mandibular teeth; usually large spiders with regular

radial webs 9. EPEIRIDAE

g3 A semicircular notch at base of leg on penultimate segment.

13. PlSAURIDAE

e2 Hinder pair of spinnerets
very long and 2 jointed.

12. AGELENIDAE
dz Eyes in 3 rows . . . 14. LYCOSIDAE

FAMILY 1. ULOBORIDAE.

A cribellum and usually a cala-
mistrum (Fig. 655) present; lateral
eyes farther apart than the 2 pairs
of median eyes; web usually round
and regular, with radiating spokes
joined by cross threads and com-
posed in part of loose bands of silk :
3 genera, and 6 American species.

1. ULOBORTTS Latreille. Cephalothorax ovate, rounded behind; eyes
all of about the same size: 4 American species.

U. plumipes Lucas. Length of female 7 mm. ; cephalothorax low ; first
pair of legs in the female twice as long as the second, with a bunch of long
hairs at the end of the middle segment ; color brown, with a median stripe

Fig. 655 — A, part of fourth leg of
Amavrobius; B, ventral view of hinder
end of same. 1, calamistrum ; 2, cribel-
lum : 3, anterior spinnerets ; 4, middle
spinnerets ; 5, posterior spinnerets ; 6,
anus. (Cambridge Natural History.)

418

AEACHN1DA

on the cephalothorax ; male without the calamistrum : common in shady
woods and bushes, especially in the lower dead branches of pines.

2. HYPTIOTES Walckenaer. Cephalothorax nearly circular, trun-
cate behind; eyes of the posterior row very much
larger than those of the anterior: 1 American species.
H. cavatus (Hentz) (Fig. 656). Length of
female 5 mm. ; abdomen ovoid, with 4 pairs of slight
elevations covered with stiff hairs ; color brown ; web
triangular in shape, with but 4 rays which radiate
from a common strand held taut by the spider, and
with cross strands : common, especially in pine woods.

Fig. 656— Web of

Hyptiotes cavatus

(Emerton).

FAMILY 2. DICTYNIDAE.

With cribellum and calamistrum in female but
not in male; lateral eyes near together on each side;
web irregular, usually a dense network of threads with a hole into which
the spider retreats, found in open places: about 35 American species.

1. DICTYNA Sundevall. Small spiders with sternum extending be-
tween the hind legs; legs without spines; all the eyes of about same
size ; head high arched, about half as wide as the thorax

and distinctly marked off from it: numerous species,
about 19 in America.

D. sublata (Hentz) (D. muraria Emerton). Body
gray in color, with dark median marking on the abdo-
men, and about 3 mm. long; cribellum large: web on
walls, fences, weeds, etc., often conspicuous because
of the dust it collects; common.

D. foliacea (Hentz) (D. volupis Keyserling).
Body about 3 mm. long; cephalothorax brown; abdo-
men yellow in the middle, and brown or red at the
sides ; legs pale ; abdomen about as wide as the cephalo-
thorax: web in bushes; common.

2. AMATJROBIUS Koch. Sternum not extending between the hind
legs; cribellum divided into 2 parts; head large and distinctly marked
off from the thorax; legs with spines: about 7 American species.

A. benneti (Blackwall) (A. sylvestris Emerton) (Fig. 657). Body
10 mm. long; cephalothorax dark brown; abdomen gray with median
yellowish markings ; the epigynum has 2 lateral lobes which meet behind :
web under stones and sticks; common.

A. ferox (Walckenaer). Like above, but the lateral lobes of the
epigynum do not meet behind: in houses, especially cellars; an European
species introduced into this country.

ig. 657 — Amau-
robius benneti
(Emerton). A, dor-
sal aspect ; B, male
pedipalp without
terminal segment.

AEANEAE 419

FAMILY 3. FILISTATIDAE.

With cribellum and calamistrum ; all the eyes close together and
upon an eminence; mandibles small; web like that of Dictyna: 1
American species.

FILISTATA Latreille. With the characters of the family: 2 species.

F. hibernalis Hentz. Body 12 mm. long with legs about twice as
long, and uniformly dark gray in color: one of the commonest house
spiders of the southern states.

FAMILY 4. DYSDEBIDAE.*

With only 6 eyes; with a pair of tracheal spiracles immediately
behind the lung spiracles : the animals build tube-like nests on the ground
under stones and other objects; 3 American genera and species.

DYSDERA Latreille. Eyes in a ring, close together; mandibles long
and inclined forward: 1 species.

D. interrita Hentz (Fig. 658). Length 12 mm.; the
abdomen but little larger than the cephalothorax; color
orange brown, lighter behind : New England.

FAMILY 5. DRASSIDAE.*

Elongated spiders with 2 claws and a bunch of flat-
tened hairs on each leg; eyes all of the same size, usually
in 2 rows; spinnerets widely separated: ground spiders Dysdera
which build tube or sac-like nests ; about 60 American species. (Emerton).

1. DRASSUS Walckenaer. Eyes in 2 slightly curved

rows, which diverge mid-dorsally, the posterior row longer than the
anterior; mandibles small; maxillae straight: 9 American species.

D. neglectus Keyserling (D. saccatus Emerton). Length 20 mm.;
color light gray, without markings; abdomen but little longer than the
cephalothorax: the animal lives under stones and makes a large trans-
parent bag of silk in which the cocoon is deposited; common.

2. GNAPHOSA Latreille. Eyes in 2 nearly straight rows, the upper
row longer than the lower; those of the middle pair of the upper row
being much nearer each other than the lateral eyes : 10 American species.

G. gigantea Keyserling (G. conspersa Thorell). Length 12 mm.;
color rusty black; cephalothorax and abdomen of about the same size;
mandibles large, with a wide serrate tooth under the claw: under stones
and leaves.

3. SERGIOLTTS Simon. Maxillae arched around the labium; the 2
rows of eyes nearly straight; no dorsal groove: 3 American species.

* See "New England Spiders of the Families Drassidae, Agelenidae, and Dysderi-
dae," by J. H, Emerton, Trans. Conn. Acad., Vol. 8, p. 1, 1890.

420

ARACHNIDA

S. variegatus (Hentz) (Fig. 659). Length 6 mm.; cephalothonfcx
bright orange in color and smaller than the abdomen, which is black
with 3 white stripes: on the ground.

FAMILY 6. PHOLCIDAB.

Eyes either 6 or 8 in number; legs very long, with
3 claws on each of the 3 hinder pairs: 6 American
genera.

PHOLCUS Walckenaer. Three large eyes in a group
on each side of the head and 2 smaller
eyes in the middle; abdomen elongate;
cephalothorax flat: 2 American species.

P. phalangioides (Fuesslin) (Fig.
660). Body 6 mm. long; longest legs 5
cm. long; color pale brown or gray: a
common house spider both in America and in Europe,
living in cellars, and making a large, flat, irregular web.

FAMILY 7. THEBIDIIDAE.*

Fig. 659

Sergiolus

variegatus

(Emerton).

_. 660
Pholcus
phalangioides —
carrying its

egg sac
(Comstock).

Usually small, light-colored spiders with a large
round abdomen; eyes of about the same size, in 2 rows,
with the end eyes near together and the middle eyes
farther apart; outer margin of mandibles parallel (ex-
cept on Steatoda) ; 3 claws on each leg : web often large,
more or less irregular in form and loose in texture, and built in the cor-
ners of rooms, on fences and rocks, and between the branches of low
trees and bushes, the spider usually staying in the web; about 300
American species.

Key to the genera of Theridiidae here described :

at Abdomen smooth and shiny, the hairs being very short 1. STEATODA

az Abdomen hairy.
&! The paired claws of the legs with a regular series of teeth almost to their

tip 2. LATHRODECTUS

62 These claws with spreading teeth at their base.

Cj Abdomen with a high, pointed hump 3. ARGYRODES

c2 Abdomen not with a hump.

di Labium and sternum united 4. SPINTHARUS

d2 Labium not united with the sternum.

d Anterior row of eyes curved 5. THERIDULA

ea Anterior row of eyes straight 6. THERIDION

1. STEATODA Sundevall. Abdomen oval, smooth, and shiny; side
eyes contiguous; those of the anterior row much larger than the middle

* See "New England Spiders of the Family Theridiidae," by J. H. Emerton,
Trans. Conn. Acad., Vol. 6, p. 1, 1882.

ARANEAE

421

Fig. 661

Steatoda borealis
(Comstock).

pair; the 2 mandibles straight and parallel to each other: the web con-
sists of a flat net held in place by numerous threads; 4 American species.
S. borealis (Hentz) (Fig. 661). Body about 6 mm. long and reddish-
brown in color, the abdomen usually with a light
stripe running around the front half and one in the
middle: among stones or in fence corners; common.
2. LATHRODECTUS Walckenaer. Abdomen round
and hairy ; side eyes widely separated : 2 American
species.

L. mactans (Fabricius) (Fig. 662). Body 12
mm. long and black, with a bright-red, hourglass-
shaped spot underneath, and one or more red spots
over the spinnerets and sometimes along the middle
of the back; abdomen of male ovoid, with a row
of red and white spots in the middle line and 4

pairs of red and white stripes on the sides:
common; web large, with a funnel-shaped retreat
in the middle.

3. ARGYRODES Simon. Abdomen with a
high pointed hump: about 13 American species.

A. trigonum (Hentz) (Fig. 663). Body yel-
low, triangular in shape, 3 mm. long and 3 mm.
high in the female; male with 2 horns in front
of eyes: common; web between branches or
leaves, or among the supporting strands of the
webs of larger spiders.

4. SPINTHARUS Hentz. Labium and sternum
united; abdomen tapering to a blunt point over
the spinnerets; side eyes close together: 1
American species.

S. flavidus Hentz. Body 4 mm. long;
cephalothorax circular; upper surface of abdo-
men flat with a white stripe on each side and
red and black in the middle: found on low
plants; web unknown.

5. THERIDULA Emerton. Anterior row of
eyes curved; first legs much longer than the
fourth: 2 American species.

T. sphaerula (Hentz). Body 2.5 mm. long; cephalothorax yellow or
orange with a median black stripe; abdomen round and wider than long,
and yellowish-gray in color with a greenish-white spot in the middle
and a black spot at either side : common in bushes.

Fig. 662 — Lathrodectus
mac tan s (Comstock).

Fig. 663 — Argyrodes tri-
gonum (Emerton).

422

ARACHNIDA

6. THERIDION Walckenaer. Anterior row of eyes straight or nearly
so; the 2 middle pairs of eyes of the same size, and equidistant from
one another: about 40 American species.

T. tepidariorum Koch (Fig. 664). Body 6 mm. long, varying in color
from whitish to black ; cephalothorax usually
light brown, the dark individuals with 6
transverse black marks on the abdomen : a
cosmopolitan species and one of the common-
est house spiders, being chiefly responsible
for the webs in the corners; it breeds sev-
eral times a year and the young and old
are found at all seasons.

T. frondeum Hentz. Body 3 mm. long,
and white or bright yellow in color, with
very variable black markings on the back,
which may consist of 2 rows of spots or a
median band: in bushes; common.

T. differens Emerton. Body about 3
mm. long; abdomen round, reddish-brown,
with a red median stripe having white
edges, which is bright in the female and
obscure in the male ; sternum orange : web on
low plants, 5 or 6 inches in diameter.

T. murarium Em. Body about 4 mm. long; abdomen round, gray in
color, with a reddish median stripe, white on the edges; sternum pale,
with a black edge and a black median stripe: on low bushes.

FAMILY 8. LINYPHIIDAE.

Small spiders with an elongate but high abdomen; mandibles with
teeth around the terminal claw ; epigynum and male appendages large and
complex : web consists of a flat or curved sheet of silk supported above and
below by great numbers of threads and found either in open woods or near
the ground in grass and dead leaves, or in caves or cellars. The smaller
species have the curious habit of flying in the late autumn. They come to
the tops of fences and other elevated objects and cause their silk to be
drawn out and floated aloft by the currents of air, until they are themselves
lifted up and often blown long distances; about 95 American species.

Key to the genera of Linypliiidae here described :
#! Female with a terminal claw on the pedipalp.
bi Hinder pair of median eyes not close together. 1. LINYPHIA

62 Hinder pair of median eyes close together 2. LEPHTHYPHANTES

o2 No such terminal claw.

&! No hard plate on the abdomen 3. ERIGONE

63 Abdomen covered by a hard plate 4. CERATINELLA

Fig. 664 — Theridion tepida-
riorum (Emerton). A, the
spider; B, its web.

ARANEAE

423

Fig. G65 — Web of Linyphia margi-
nata ( Emerton ).

1. LINYPHIA Latreille. Legs with long spines along their sides;
maxillae longer than wide; hinder pair of median eyes not near to-
gether; terminal segment of male pedipalp very large and complex:
about 22 American species.

L. marginata Koch (Fig. 665).
Body 4 mm. long; cephalothorax long
and high in front * legs long and slen-
der; color light yellow with median
brown markings : web a dome 4 or 5
inches in diameter hung between plants
or rocks, in the middle of which the
spider lives; one of the commonest
spiders in shady woods.

L. phrygiana Koch. Body 5 mm.
long; color light yellow with a median
black stripe which is serrated on both
margins on the abdomen: web a large
sheet, common in woods and near
houses.

2. LEPHTHYPHANTES Menge. Maxillae longer than wide; legs with
long spines along their sides; hinder pair of median eyes near together;
sternum heart-shaped; penultimate joint of the legs with' a single spine:
4 American species.

L. nebulosus (Sundevall) (Fig. 666). Length 4
mm.; color variable, usually light brownish-yellow with
gray markings: common in cellars and damp places about
houses, the web being flat.

3. ERIGONE* Savigny and Audouin. Pedipalp
in the female without a claw ; body rather narrow :
very small spiders which live near the ground in grass,
dead leaves, etc., in small webs; about 30 American
species.

E. longipalpis (Sundevall). Body 2 mm. long, dark
brown in color; cephalothorax smooth and shiny and
sometimes bright orange in color; small pointed teeth
along the sides of the thorax.

E. autumnalis Emerton. Body 1.2 mm. long, of a light color with
a bright yellow head.

4. CERATINELLA Emerton. Abdomen covered by a hard plate;
pedipalp of female without a claw: 21 American species.

Fig. 666

Lephthyphan-

tes nebulosus

(Comstock).

* See "A Catalogue of the Erigonae of North America," etc., by C. R. Crosby,
Proc. Acad. Nat. Sci., Phila., 1905.

424

ARACHNIDA

C. fissiceps (Cambridge). Body 1.5 mm.; abdomen round, and
orange in color; head black around the eyes; the head of the male
extends forwards, forming two humps: very common on small bushes.

FAMILY 9. EPEIRIDAE.*

Round-web spiders. Usually large spiders with long legs and an
abdomen which is rounded or ovoid and often provided with humps; often
brightly colored; cephalothorax short, low in front with the eyes near

the front edge and in 3 transverse
groups, the 2 lateral pairs being close
together and separated from the mid-
dle eyes; 3 terminal claws on each
foot, usually with accessory spines
also. The web is round and regular,
with radiating spokes joined by cross
threads (Fig. 667). The latter form
2 spirals, an inner spiral that begins
in the center and winds outwards,
covering usually less than a quarter
of the finished web, and an outer
spiral that begins at the edge and
winds inwards, covering a large part
of the web. The outer spiral is
formed of a sticky thread which holds
the insects flying against it. The

spider usually tears down its web and builds a fresh one every night:
this may be for the purpose of renewing the sticky thread, which gradu-
ally hardens. About 120 American species are known.
Key to the genera of Epeiridae here described :

Cj Abdomen not elongate, usually round or ovoid.

&! Hinder row of eyes strongly curved ; large brightly colored spiders. 1. ARGIOPE
62 Hinder row of eyes not curved or only slightly so.
<?! Thorax without a deep longitudinal furrow.

dt Head and thorax separated by a deep transverse cervical groove. 2. CYCLOSA
dz No distinct cervical groove ; thorax usually with a V-shaped furrow.
Cj. Abdomen without spines.

fi Web entire 3. EPEIBA

/2 Web lacking a large segment 4. ZILLA

e: Abdomen with prominent spines 5. ACROSOMA

c2 Thorax with a deep longitudinal furrow 6. MANGORA

aa Body elongate and light-colored.

6X Groove between the spiracles curved markedly 7. TETRAGNATHA

bt This groove nearly straight 8. LEUCAUGE

* See "New England Spiders of the Family Epeiridae," by J. H. Emerton, Trans.
Conn. Acad., Vol. 6, p. 295, 1884. "American Spiders," etc., by H. McCook, Vol. 3, p.
132, 1893.

Fig. 667 — An orb web (Emerton).
1, inner spiral ; 2, outer spiral ; 3,
strand going to the nest

AKANEAE

425

1. ARGIOPE Savigny and Audouin. Cephalothorax flat; head very
small; eyes all alike, the second row strongly curved, first row straight
or curved: about 5 American species.

A. aurantia Lucas (A. riparia Emerton) (Fig. 668). Body large
and conspicuous, being often 25 mm. long, with long legs; abdomen
black and 2 bright yellow or orange bands underneath; cephalothorax
gray above and yellow underneath : the web is sometimes 2 feet in diam-
eter and has a zigzag band of silk across the middle; the male has a
small, irregular web nearby ; in grass and bushes ; in open fields, especially
near water.

A. trifasciata (Forskal) (A. transversa Em.). Like the above, but
a little smaller; abdomen white or light yellow, crossed by black lines:
web often in marshes.

2. CYCLOSA Menge. Head and thorax
of the female separated by a deep trans-
verse groove: 5 American species.

C. conica (Pallas). Abdomen with a
blunt conical lump at its hinder end;
length 6 mm.; color gray: the web has a
band of silk across it in which the spider
fastens sticks and rubbish, and is pro-
tected by its resemblance to them.

3. EPEIRA Walckenaer (Araneus
Simon). Thorax without a transverse
furrow; the 2 rows of eyes straight or
nearly so, 4 eyes being median in posi-
tion and a pair at some distance from
tkem on each side: about 57 American
species.

E. foliata Koch (E. strix Hentz).
Length 8 mm.; color brown, with a broad
scalloped stripe on the back of the abdomen; cephalothorax with 3 lon-
gitudinal stripes: common all over the country around houses and on
bushes and fences.

E. angulata (Clerck). Length 12 mm.; color dark brown, with a
yellow stripe on the sternum and yellow spots on the under side of the
abdomen; anterior end of abdomen with a pair of humps and a yellow
spot: common among trees.

E. cavatica Keyserling (E. cinerea Emerton). Length 18 mm.; color
dirty white with grayish markings; long white hairs scattered over the
body; abdomen with 2 small humps in front: common about houses and
barns in New England.

Fig. 668 — Argiope aurantia
(Emerton).

428

AEACHNIDA

Fig. 672

Tmarus caudatua
(Emerton).

1. TMARTTS Simon. Front of head truncate; hinder row of eyes
much longer than the forward; lateral eye on each side being raised on
tubercles, the hinder tubercle on each side being much larger than the
forward one; abdomen high and pointed behind: 5 American species.
T. caudatus (Hentz) (Fig. 672). Length 6 mm.; color mottled
gray; abdomen highest at hinder end, which forms
a conical knob: on trees and fences; common.

2. MlSUMENA Latreille. Large, brightly colored
or white spiders living in flowers, the colors of
which they often mimic; the 2 lateral eyes on each
side on a single tubercle : about 20 American species.
M. vatia Thorell. Length 12 mm.; color white
or yellow, sometimes with a crimson spot on each
side of the abdomen and another between the eyes;
sides of thorax yellowish : common.

M. asperata (Hentz). Length 6 mm.; color pale yellow or white,
with dull red markings on the abdomen and a brown stripe on each side
of the thorax; scattered stiff hairs present; common.

3. XYSTICUS Koch. Each lateral eye on a tu-
bercle, the forward one being the larger ; median ocular
area as wide or wider in front than behind : 40 Ameri-
can species, which live under bark, stones, and leaves.

X. triguttatus Keyserling. Length 5 mm. ; females
straw-colored or yellow, with black spots on the
thorax and front of the abdomen and 3 broken trans-
verse stripes behind; male with a thorax which is dark
brown at the sides and lighter in the middle, and an
abdomen banded with black and white: very common
in grass and low bushes.

X. versicolor (Keyserling) (Fig. 673), Length 7
mm.; body flattened, mottled black and gray in color:
common on trees, fences, etc.

4. PHILODROMUS Walckenaer. Abdomen bluntly
pointed behind and flat; legs long, the second pair
being the longest; labium much longer than wide: 24
American species.

P. vulgaris (Hentz) (Fig. 674). Length 6 mm.
spreading an inch or more; color mottled gray with a median marking
on the abdomen: on fences and walls.

5. EBO Keyserling. Labium not longer than wide; second pair of
legs twice as long as any of the others; median eyes larger than the
lateral ones; hinder row nearly straight: 3 American species.

Fig. 673

Fig. 674

Fig. 673— Xys-
ticus versicolor
(Emerton). Fig.
674 — Philodro-
mus vulgaris
(Emerton).

legs very long,

AEANEAE

429

Fig. 675

Tibellus

oblongus

(Emerton).

E. latithorax Keys. Length 3 mm.; color gray and white, with
black spots; body very wide; head narrow in front.

6. TIBELLTJS Simon. Body long and slender, the legs
projecting ahead and behind and not sideways; both
rows of eyes curved: 2 American species.

T. oblongus (Walckenaer) (T. duttonii Emerton) (Fig.
675). Length 12 mm.; width 2 mm.; color gray or yellow,
with dark longitudinal bands and a pair of black spots
on the hinder part of the abdomen: very common on
bushes and grass.

FAMILY 11. CLUBIONIDAE.

Light-colored spiders usually without color markings;
upper row of eyes longer and the eyes usually larger
than the under row; mandibles of females swollen at
the base : the animals live in flat tubular webs in rolled-up
leaves or on plants and under bark and stones; about 95
American species.

Key to the genera of Clubionidae here described:

a^ Posterior spinnerets with a very distinct, conical terminal segment.
&! Labiuni much longer than wide and extending beyond the middle of the

maxillae 1. CLUBIONA

5a Labium about as long as wide or less so, and not extending beyond the
middle of the maxillae ; sternum extending between the hind legs.

2. PHEUBOLITHUS

aa Posterior spinnerets with a very short and fre-
quently indistinct terminal segment.
&! Cervical groove present.

cx Legs spiny 3. CASTIANEIBA

c2 Legs not spiny 5. TKACHELAS

62 Cervical groove absent 4. MICARIA

1. CLUBIONA Latreille. Hinder legs longer
than forward; spinnerets distinctly segmented;
labium longer than wide ; mandible long ; eyes very
near the front margin of head : about 20 American
species.

C. obesa Hentz (C. crassipalpis Keyserling)
(Fig. 676). Length 6 mm.; pale in color, without
markings; mandibles and ends of male pedipalps
dark; eyes in each row equidistant, the hinder
row being the longer: common.
2. PHRUROLITHUS Koch. Each terminal claw with 6 to 10 spatu-
late hairs; sternum broad and extending between the hind legs: 8
American species.

Fig. 676 — CluUona
obesa (Emerton).

430 ARACHNIDA

P. alarms (Hentz) (Fig. 677). Length 3 mm.; cephalothorax light
yellowish, with a black line on each edge; abdomen covered with irides-
cent scales which change in color from grayish-green to pink : a very active
spider living among stones on the ground.

3. CASTIANEIRA Keyserling. Cervical groove pres-
ent; anterior median eyes not close to the margin of the
head; legs spiny: about 18 American species.

C. descripta (Hentz) (C. crocata Emerton). Length
8 mm.; body black, with a bright red spot on the end of
the abdomen; ends of legs yellow: among stones in dry,
open places; its egg case is a small parchment-like disc
attached to a rock.

4. MICARIA Westring. Body covered with scale-like
hairs; last segment of the hind spinnerets very short,
frequently indistinct, with an oblique groove; no cervical
groove: 13 American species.

M. aurata (Hentz). Body resembles an ant in size
and color; length 6 mm.; color light brown, varying to
bright yellow and orange: eastern states.

5. TRACHELAS Koch. Posterior row of eyes curved forward ; legs with-
out or with few spines, dorsal groove present: about 5 American species.
T. tranquilla Hentz (T. ruber Keyserling). Length 8 mm.; cephalo-
thorax wide; abdomen ovoid; color deep orange brown, the abdomen
much lighter than the cephalothorax: under stones and leaves.

FAMILY 12. AGELENIDAE.

The funnel-web spiders. Cephalothorax large, and often narrow in
front and broad behind; cervical groove present; hind spinnerets very
long and 2-jointed ; mandibles large ; 3 terminal claws on the feet : mostly
large spiders which make a flat web on the grass and in the corners in
barns and cellars, in the middle of which is a funnel-shaped tube form-
ing the spider's retreat; about 50 American species.
Key to the genera of Agelenidae here described :
Oj Spinnerets not in a transverse line.

&! Both rows of eyes strongly curved backward 1. AQELENA

6, Both rows of eyes not or but slightly curved backward.

Cj Anterior median eyes much smaller than the lateral 2. CORAS

Cj Anterior median eyes either equal in size or smaller than the lateral.

3. TEGENABIA
a, Spinnerets in a straight or curved line 4. HAHNIA

1. AGELENA Walckenaer. Both rows of eyes strongly curved back-
wards so that the anterior median and the posterior lateral are in a
straight line; terminal segment of the hind spinnerets at least as long
as the basal segment: about 4 American species.

ARANEAE

431

Fig. 678 — Agelena
ncevla (Emerton)

A. naevia Walck. Grass spider (Fig. 678). Body 18 mm. long or
less, and yellowish brown, or black in color, with gray or dark markings
and spots on the abdomen and broad longitudinal stripes on the cephalo-
thorax, and covered with fine hairs: the very
common spider which makes flat webs in the
grass which are conspicuous when covered by
dew; also in houses.

2. CORAS Simon. Rows of eyes not curved
or but slightly so; anterior median eyes much
larger than the lateral: 1 species.

C. medicinalis (Hentz) (Fig. 679). Body
12 mm. long, light yellowish-brown in color and
covered with gray hairs; abdomen large and
oval and marked with gray
spots of irregular shape: in
woods among rocks and under
loose bark, the web is not flat,
but is usually curved in sev-
eral places.

3. TEGENARIA Latreille. Eyes all of the same
size, both rows curved, the forward row but slightly;
legs long and slender: about 7 American species.

T. derhami (Scopoli). Body 10 mm. long, pale
in color, with gray stripes and spots; first and fourth
pairs of legs the longest: in cellars, barns, etc.; the
web often forms a thick shelf in the
corner; very common, having been im-
ported from Europe, it and Theridion
tepidariorum making most of the corner
webs in cellars.

4. HAHNIA Koch. Spinnerets extend across the abdo-
men in a straight or curved line; anterior middle eyes
smaller than the lateral: about 6 American species.

H. agilis Keyserling (H. bimaculata Emerton) (Fig.
680). Length 3 mm.; cephalothorax bright orange brown
in color and the legs and abdomen pale yellowish with gray markings:
common under stones and leaves or among grass and moss.

FAMILY 13. PISAUBIDAE.

Eyes in 3 rows; cocoon earned in the mandibles of the female;
cephalothorax broad and flat: ground spiders of large size similar to the
Lycosidae; about 18 American species.

Fig. 679 — Coras
medicinalis
(Emerton).

Fig. 680

HaJinia agilis,

ventral aspect

(Emerton).

430 ARACHNIDA

P. alarms (Hentz) (Fig. 677). Length 3 mm.; cephalothorax light
yellowish, with a black line on each edge; abdomen covered with irides-
cent scales which change in color from grayish-green to pink : a very active
spider living among stones on the ground.

3. CASTIANEIRA Keyserling. Cervical groove pres-
ent; anterior median eyes not close to the margin of the
head; legs spiny: about 18 American species.

C. descripta (Hentz) (C. crocata Emerton). Length
8 mm.; body black, with a bright red spot on the end of
the abdomen; ends of legs yellow: among stones in dry,
open places; its egg case is a small parchment-like disc
attached to a rock.

4. MICARIA Westring. Body covered with scale-like
hairs; last segment of the hind spinnerets very short,
frequently indistinct, with an oblique groove; no cervical
groove: 13 American species.

Phrur'oiithus M. aurata (Hentz). Body resembles an ant in size

(Emerton). and color; length 6 mm.; color light brown, varying to

bright yellow and orange: eastern states.

5. TR ACHE LAS Koch. Posterior row of eyes curved forward ; legs with-
out or with few spines, dorsal groove present: about 5 American species.
T. tranquilla Hentz (T. ruber Keyserling). Length 8 mm.; cephalo-
thorax wide; abdomen ovoid; color deep orange brown, the abdomen
much lighter than the cephalothorax: under stones and leaves.

FAMILY 12. AGELENIDAE.

The funnel-web spiders. Cephalothorax large, and often narrow in
front and broad behind; cervical groove present; hind spinnerets very
long and 2-jointed ; mandibles large ; 3 terminal claws on the feet : mostly
large spiders which make a flat web on the grass and in the corners in
barns and cellars, in the middle of which is a funnel-shaped tube form-
ing the spider's retreat; about 50 American species.
Key to the genera of Agelenidae here described:
Oj Spinnerets not in a transverse line.

&t Both rows of eyes strongly curved backward 1. AGELENA

6, Both rows of eyes not or but slightly curved backward.

Cj Anterior median eyes much smaller than the lateral 2. CORAS

ca Anterior median eyes either equal in size or smaller than the lateral.

3. TEGENABIA
Oj Spinnerets in a straight or curved line 4. HAHNIA

1. AGELENA Walckenaer. Both rows of eyes strongly curved back-
wards so that the anterior median and the posterior lateral are in a
straight line; terminal segment of the hind spinnerets at least as long
as the basal segment: about 4 American species.

AEANEAE

431

Fig. 678 — Agelena
ncevia (Emerton)

A. naevia Walck. Grass spider (Fig. 678). Body 18 mm. long or
less, and yellowish brown, or black in color, with gray or dark markings
and spots on the abdomen and broad longitudinal stripes on the cephalo-
thorax, and covered with fine hairs: the very
common spider which makes flat webs in the
grass which are conspicuous when covered by
dew; also in houses.

2. COEAS Simon. Rows of eyes not curved
or but slightly so; anterior median eyes much
larger than the lateral: 1 species.

C. medicinalis (Hentz) (Fig. 679). Body
12 mm. long, light yellowish-brown in color and
covered with gray hairs; abdomen large and
oval and marked with gray
spots of irregular shape: in
woods among rocks and under
loose bark, the web is not flat,
but is usually curved in sev-
eral places.

3. TEGENARIA Latreille. Eyes all of the same
size, both rows curved, the forward row but slightly;
legs long and slender: about 7 American species.

T. derhami (Scopoli). Body 10 mm. long, pale
in color, with gray stripes and spots; first and fourth
pairs of legs the longest: in cellars, barns, etc.; the
web often forms a thick shelf in the
corner; very common, having been im-
ported from Europe, it and Theridion
tepidariorum making most of the corner
webs in cellars.

4. HAHNIA Koch. Spinnerets extend across the abdo-
men in a straight or curved line; anterior middle eyes
smaller than the lateral: about 6 American species.

H. agilis Keyserling (H. bimaculata Emerton) (Fig.
680). Length 3 mm.; cephalothorax bright orange brown
in color and the legs and abdomen pale yellowish with gray markings:
common under stones and leaves or among grass and moss.

FAMILY 13. PISAUEIDAE.

Eyes in 3 rows; cocoon carried in the mandibles of the female;
cephalothorax broad and flat: ground spiders of large size similar to the
Lycosidae; about 18 American species.

Fig. 679 — Coras
medicinalis
(Emerton).

680
agilis,
ventral aspect
(Emerton).

432 AEACHNIDA

1. PISAURINA Simon. Anterior row with 4 eyes of same size and
straight ; area of the middle eyes longer than broad : 3 American species.

P. undata (Walckenaer). Length 13 mm.; color light brownish-
yellow, with a wide, median, dark band edged with white running
the length of the body; abdomen long and narrower than the cephalo-
thorax : common in bushes ; no web is made
until the young are ready to hatch, when
the female builds a small web about the
cocoon in which the young may live.

2. DOLOMEDES Latreille. Area of the
middle eyes as broad or broader than long; anterior
row of eyes curved forward : 7 American species.

D. fontanus Emerton (D. tenebrosus Em.) (Fig.
681). Length 20 mm., with legs spreading 10 cm.;
color gray; cephalothorax larger than the abdomen
and with light bands on the side ; abdomen with dark
cross lines: common on the ground in low
bushes near water with habits like P.
undata.

D. sexpunctatus Hentz. Length 15
mm.; color dark greenish-gray, with a whitish line
on each side of the length of the body; abdomen
larger than the cephalothorax; sternum with 6 dark

spots : common under stones near the water on which 'Fig. 681

Dolomedes fontanus
it runs readily. (Emerton).

FAMILY 14. LYCOSIDAE.*

Wolf spiders. Large, active spiders which live on or near the
ground; eyes usually in 3 rows; in the front row are 4 small eyes and
back of these 2 pairs of large eyes; cephalothorax high and prismatic;
feet with 3 claws, the small one surrounded by hairs : no web built, but
many species line their retreats with silk; the cocoon is attached to the
spinnerets and the young spiders are earned for a short time on the
mother's back; about 114 American species.

Key to the genera of Lycosidae here described:

Oj Labium longer than broad.
5i Posterior spinnerets not longer than the anterior or but slightly so.

<?! Cephalothorax highest in the cephalic region 1. LYCOSA

ca Cephalothorax highest in the middle 2. TROCHOSA

62 Posterior spinnerets half again as long as the anterior 4. PIRATA

o2 Labium at least as broad as long 3. PARDOSA

* See "New England Lycosidae," by J. II. Emerton, Trans. Conn. Acad., Vol. 6, p.
481, 1885. "Canadian Spiders," by same, ibid., Vol. 9, 1895. "Descriptions of North
American Araneae of the Families Lycosidae and Pisauridae," by T. H. Montgomery,
Proc. Acad. Nat. Sci., Phila., 1904, p. 261.

AEANEAE 433

1. LYCOSA Latreille. Head very high and with sloping sides;
labium longer than broad; hinder 2 pairs of eyes not on the margin
of the head; legs usually long and with long spines: about 50 American
species.

L. helluo Walckenaer (L. nidicola Emerton). Length 18 mm.; long-
est legs 25 mm.; color dull yellow or greenish-brown, with 3 narrow
yellow stripes on the cephalothorax and a pointed stripe on the front
half of the abdomen : common under stones in moist meadows and woods ;
the female is seen with her cocoon in early summer.

L. avida Walck. (L. communis Em.) (Fig. 682). Length 10 mm.;
longest legs 18 mm. ; color from gray to black, with 3 light stripes on the
cephalothorax and a pair of broad median stripes meeting behind on the
abdomen: common in pastures, the female is carry-
ing her cocoon in early summer.

L. rabida Walck. (L. scutulata Hentz). Length
^ mm.; longest legs 26 mm.; cephalothorax dark
gray in color, with 3 light stripes; abdomen with a
wide median stripe and several light and dark lines
at each side.

L. carolinensis Walck. One of our largest
spiders, sometimes over 35 mm. long with legs
spreading 75 mm. ; body covered with thick hair and
brown above and black beneath in color: on the
ground or in its hole, a deep cylindrical pit, in which
the eggs are hidden.

L" P*ei Marx V* anmieola Scudder). Sand
spiders. Length 18 mm.; color of male gray or sand
color, with a spot in the middle of the abdomen, female gray or slate
color, with a broad, serrate band on the abdomen: the female lives in
a hole 10 inches deep, around the mouth of which is sometimes a low
turret of sticks.

2. TROCHOSA Koch. Legs quite short; first row of eyes about as
long as the second, which is not quite as long as the third row: 4
American species.

T. cinerca (Fabricius). Length 12 mm.; body gray or sand color
with small spots : common on beaches and in sandy fields.

3. PARDOSA Koch. Slender spiders with long legs; labium at least
as broad as long; front row of eyes shorter than the second; second and
third pair of eyes large and near the lateral margin of the head: 30
American species.

P. nigropalpis Emerton. Length 6 mm.; color black with a wide,
irregular median area; pedipalps of male black: on the ground.

434

ARACHNIDA

Fig. 683 — Fir at a,
piratica (Emerton).
A, dorsal aspect ; B,
front view, showing
the eyes.

4. PIEATA Sundevall. Labium longer than broad; first row of eyes
as broad as the second: beneath stones and in the grass near the water
over the surface of which they may freely run; 16 American species.
P. piratica (Clerck) (P. marxi Stone) (Fig. 683). Length 6 mm.;
color pale yellow with gray or black markings;
eyes of the second row about half their diameter
apart.

FAMILY 15. ATTIDAE.*

Jumping spiders. Eyes in 3 rows, the front
row usually curved and composed of 4 large eyes,
the second row of 2 very small eyes, the third row
far back on the head and composed of 2 large eyes
which are usually turned a little backward; cepha-
lothorax large and wide in front; legs strong and
short and with 2 terminal claws on each; body cov-
ered with hairs or scales: no web made, but some
species make silk bag-like retreats on plants and

under stones; the spiders run and jump sidewards and backwards as well

as forwards; about 213 American species.

Key to the genera of Attidae here described :

«! Body not shaped like an ant.
&! Abdomen not longer than the hind legs.
Cj Body not noticeably flattened.
di Front row of eyes not touching one another.

€i Eye area broader than long, body short and wide 1. ATTUS

e2 Eye area not broader than long.

/! Eye area somewhat wider behind than in front 2. PHIDIPPUS

/2 Eye area quadrangular 3. DENDRYPHANTES

d2 Eyes of front row touch one another 4. S ALTICUS

c2 Body noticeably flattened 5. MABPISSA

&2 Abdomen longer than hind legs 6. HYCTIA

o3 Body like an ant in shape 7. SYNEMOSYNA

1. ATTTTS Walckenaer. Eye area broader than long;
first leg with 2 rows of spines on distal half; third leg
shorter than the fourth: about 6 American species.

A. palustris Peckham (Fig. 684). Length 6 mm.;
color brown or gray, with a median white line on the
cephalothorax; abdomen with white spots and markings:
on plants, with nests among the leaves.

2. PHIDIPPUS Koch. Cephalothorax high; eye area wider behind
than in front ; first leg thick and long ; third leg shorter than the fourth :
about 50 American species.

* See "Attidae of North America," by G. W. and E. G. Peckham, Trans. Wis.
Acad. Sci., Vol. 7, 1888. "New England Spiders of the Family Attidae," by J. H.
Emerton, Trans. Conn, Acad., Vol. 6, p. 220, 1891.

Fig. 684— At-

tus palustris

(Emerton).

AEANEAE

435

Fig. 685— Phidip-

pus podagrosus

(Einerton).

P. podagrosus Hentz (P. multiformis Emerton) (Fig. 685). Length
8 mm.; males black, with white and orange markings on the abdomen;
female brown, mixed with black, white, and yellow,
there being 3 or 4 pairs of white spots on the abdo-
men of both sexes : very common on plants, with bag-
like nests among the leaves.

P. audax Hentz. Length 12 mm.; color black,
with 3 large, white spots on the abdomen and several
smaller ones: common under stones and sticks where
it has a nest.

3. DENDRYPHANTES Koch. Second and third
rows of eyes both small ; eye area forms a quadrangle ;
cephalothorax rather high and short;
third leg shorter than fourth: about
22 American species.

D. capitatus (Hentz) (D. cestiva-
lis Peckham). Length 5 mm.; legs
ringed; color variable, in male dark brown with a white
stripe on each side, in female light yellow with 4 pairs
of brown spots on the abdomen: common on bushes.

4. SALTIOTTS Latreille (Epiblemum
Hentz). Eyes of front row touching one
another; mandibles of male very long and
projecting in front of head: 4 American
species.

S. scenicus (Clerck) (Fig. 686). Length 6 mm.; gray
in color with 2 pairs of oblique, white spots on the abdo-
men and 2 white spots 011 the cephalothorax: one of
the commonest jumping spiders, on houses and fences;
also in Europe.

5. MARPISSA Koch (Marptusa Thorell). Cephalo-
thorax and abdomen both widened in the middle and of
about the same size; legs long and thick: 6 American
species.

M. familiaris (Hentz). Length 12 mm.; body flat-
tened, gray in color; cephalothorax with a dark brown
band along each side; abdomen with a broad, irregular,
yellowish-white median band: common on houses and
fences.

6. HYCTIA Simon, Abdomen long and slender and

narrower than the cephalothorax ; front legs much larger than the others :
2 American species.

Fig. 686— Balti-
cus scenicus
(Emerton).

Fig. 687
Hi/ctia pikei
(Emerton).

436

ARACHNIDA

H. pikei Peckham (Fig. 687). Body 8 nim. long and very slender,
with the abdomen twice as long as the cephalothorax and longer than the
hind legs; abdomen with a very broad, black stripe having 3 notches on
each side; rest of the body whitish; front legs brown, others white:
common on sand and grass, on which it often lies with the legs parallel
to the body, so that it would be seen with difficulty.

7. SYNEMOSYNA Hentz. Cephalothorax and abdomen each with a
deep dorsal depression; middle of the body slender, front middle eyes
large, the rest small : 1 species.

S. formica Hentz. Ant-like spider (Fig. 688). Body 6 mm. long
and very slender; cephalothorax narrowed behind and the abdomen in
front, and each has a deep dorsal depression in the middle ;
color black with yellowish markings: the spider resembles
an ant in shape and method of walking.

ORDER 8. ACARINA.*

The mites. Small arachnids, in which cephalothorax
and abdomen are unsegmented and so joined that the short,
thick body is more or less ovoid or globose in shape. In
some forms a suture separates the forward part of the body
with two pairs of legs from the hinder part with the two
hinder pairs; in a few also the abdomen is elongated and
annulated, although not segmented. The six pairs of ap-
pendages are well developed and consist of the mandibles
and pedipalps and four pairs of legs, except in the Erio-
pJiyidae, which have but two pairs. The mandibles may be
chelate or formed for piercing and sucking. The pedipalps are usually
more or less leg-like, with five joints or less, and in some forms they
are chelate or subchelate; the basal joints may form plates called
the maxillae, or they may unite to form a lip or labium. Accessory
mouth parts are often present, as a hypostoine or under lip and tongue,
and an upper lip or epistome; the latter may be united with the
lip below to form a tube called the rostrum, from which the man-
dibles protrude. The legs are usually 5-jointed and end each with two
claws. The external surface of the body is more or less covered with
tactile hairs or with scales. Eyes are either present or absent. The

* See "A Treatise on the Acarina or Mites," by Nathan Banks, Proc. U. S. Nat.
Mus., Vol. 28, p. 1, 1905. "A Catalogue of the Acarina or Mites of the United
States," by Nathan Banks, same, Vol. 32, p. 595, 1907. "The Life History and
Binomics of Some North American Ticks," by W. A. Hooker and others, Bull. 106,
Bur. Ent., U. S. Dept. Ag., 1912. "New Mites," by II. E. Ewing, Bull. Am. Mus.
Nat. Hist., Vol. 32, p. 93, 1913. "The Acarina," by N. Banks, Rep. 108, Bur. Ent.,
1915.

Fig. 688
Synemosyna

lor mica
(Emerton).

AEANEAE 437

anus is at the binder end of the body; the genital pore lies in front
of it.

The internal structure is characterized by its compactness. The
digestive tract is well developed. Two Malpighian tubules, if any, are
present. Many forms have no special respiratory system; others have
tracheae, which open to the outside through a pair of spiracles situated
either at the base of the mandibles or near the hind legs.

The nerve ganglia are all united into a single mass, which is pierced
by the oesophagus. Mites are unisexual animals. The young animal is
usually bom as a larva with six legs (Fig. 713, C) ; after feeding awhile
it passes into a resting stage, from which it emerges as a so-called
nymph, which has eight legs but no genital orifice; at the end of the
nymphal stage it again becomes quiescent and develops into the adult.
In some forms the development is abbreviated and the young animal is
born as a nymph, or even as an adult. The six-legged larval stage has
been observed in certain species to be preceded by an eight-legged embry-
onic stage, which seems to indicate that the former condition is not a
primitive one.

Most mites are land animals and about half the species are parasitic,
many, as the itch and mange mites and the ticks, being among the most
troublesome and even dangerous parasites infecting man and his domestic
animals. Many are parasitic on insects, especially on beetles and ants.
A few are entoparasites, Halarachne, living in the trachea of seals, and
Pneumonyssus, in the lungs of a monkey. The non-parasitic forms eat
small animals, including each other, and also decaying plant or animal
matter, and are found on plants and the ground, under bark or dead
leaves, while some form galls on plants. The Hydrachnidae and Halaca-
ridae are aquatic, the former living in fresh and the latter in salt water.
They are, however, very little modified for swimming, and possess no gills.
The order contains about 3,000 species, about 500 being known in this
country. These are grouped in about 26 families.

Key to the families of Acarina here described :

Ot Body elongate and worm-like, the hinder part ringed ; animals minute.

6t Gall mites ; but 4 legs present 1. ERIOPHYIDAE

62 Eight legs present ; mammalian parasites 2. DEMODICIDAE

aa Body not worm-like.

&! No spiracles or trachea present ; minute mites.
Cj On mammals or birds,
dj Itch and mange mites ; parasites in the skin of mammals. .3. SARCOPTIDAE

d2 Bird mites ; among the feathers of birds 4. ANALGESIDAE

c2 In fruit, grain, cheese, etc., and in certain plants 5. TYROGLYPHIDAE

62 Spiracles and tracheae usually present.
ca Horny mites ; a pair of usually club-shaped bristles on cephalothorax.

6. OBIBATIDAE
ca No such bristles.

438

ABACHNIDA

di Each spiracle in a stigmal plate (Fig. 700, C) near the fourth pair of legs.
ev Stiginal plate in front of fourth leg.

/! Not on birds (except the genus Dermanyssus) . .7. GAMASIDAE

/3 Parasitic on birds 8. ARGASIDAE

e2 Stigmal plate behind fourth leg 9. IXODIDAE

da Spiracles not in stigmal plates, but at the base of the mandibles or near

the fourth pair of legs.
e^ Aquatic mites.

A Fresh-water mites 10. HYDRACHNIDAE

/2 Salt-water mites 11. HALACARIDAE

ea Not aquatic.

A Mandibles long and snout-like 12. BDELLIDAE

/, Mandibles not so ; body often red.

0i Mandibles chelate ; eyes stalked 13. TROMBIDIIDAE

gz Mandibles piercing ; eyes sessile.

^ Mid-dorsal line present; not web-spinning. . . .14. RHYNCHOLOPHIDAE
A2 No mid-dorsal line ; web-spinning 15. TETRANYCHIDAE

FAMILY 1. EEIOPHYIDAE.* (PHYTOPTIDAE.)

Gall mites. Body minute and worm-like, the hinder
part being greatly prolonged and ringed ; eyes and tracheae
absent ; but 2 pairs of legs present, the hinder 2 parts being
represented by wart-like projections or by hairs; pedipalps
leg-like and 3- jointed, and holding between them the ros-
trum, in which lie the needle-like mandibles; anus at the
hinder end. The animals feed on plant juices and are the
cause of galls, fuzzy spots, and other deformed structures
on plants. The gall always has an opening (differing in
this respect from those of the Hymenoptera and the Dip-
tera, but not the Bomoptera) and vary much in form
among the different species. A fuzzy spot or erineum is a
dense mass of twisted hairs, among which the mites live.
Some of these mites live in buds and kill them, others cause
the edge or surface of a leaf to curl or fold, while still
others produce abnormal growths on twigs. The family
contains about 227 species, 27 species being American.

ERIOPHYES von Siebold (Phytoptus Dujardin).
Number of rings about the same on upper and under sides
of the body: about 144 species, 22 American.
E. pyri (Pagenstecker). Pear-leaf blister. Length .19 mm.; width

.05 mm.: causes round, red spots on pear leaves, the opening being on

the under side; the animals winter in the leaf buds.

* See "The Phytopti and Other Injurious Plant Mites," by H. Carman, Twelfth
Rep. of St. Ent. Illinois, 1883, p. 23. "Eriophyidae," by A. Nalepa, Das Tierreich,
1898. "Galls and Insects Producing Them," by M. S. Cook, Ohio Nat., Vol. 2, p. 263 ;
Vol. 3, p. 419 ; and Vol. 4, p. 125, 1902-04. "The Eriophyidae, Part I, The Apple and
Pear Mites," by P. J. Parrott, H. B. Hodgkins and W. J. Schoener, Bull. 283, N. Y.
Ag. Ex. St., 1906.

Fig. 689
Eriophyes

vitis
(Banks).

ACAE1NA

439

E. vitis (Landois) (Fig. 689). Produces an erineum on the under
side of grape leaves, which causes a swelling on the upper side; length
.16 mm.; width .032 mm.

E. quadripes (Shimer). Produces round galls on
leaves of the soft maple.

FAMILY 2. DEMODICIDAE.*

Body minute and worm-like, the hinder part being
greatly prolonged and ringed; eyes and tracheae absent;

4 pairs of 3-jointed legs; pedipalps close against the ros-
trum ; anus just back of the hind legs : 1 genus with about

5 species.

DEMODEX Owen. With the characters given above:
several species, which live in sebaceous glands and hair
follicles of man and the domestic animals.

D. folliculomm Simon (Fig. 690). Length .4 mm. or less; width
.05 mm.: in the skin of the human face, supposed to be the cause of
" blackheads "; also in cattle and hogs.

D. bovis Stiles. Length .25 mm.; width .064 mm.: in the skin of
cattle, causing swellings of the size of a pea in the hide.

FAMILY 3. SAECOPTIDAE.*

Itch mites. Body minute, globular, or ovoid in shape, finely striated
on the surface and with a few long bristles; eyes and tracheae absent;
legs short, each ending in 1 or 2 claws or a stalked or sessile sucker or a

Fig. 690

Demodex

folliculorum

(Banks).

Fig. 691 — Sarcoptes scabiei (Banks). A, dorsal aspect of female; B, ventral aspect
of male ; C, a mite in its burrow.

bristle; pedipalps close against the rostrum; mandibles usually chelate:
in the skin of mammals and a few birds, causing itch and mange. The
female burrows through the skin, feeding on the tissues, and leaving a
row of eggs behind her, and finally dies at the end of her burrow. The

See "Demodicidae et Sarcoptidae," Das Tierreich, 1899.

440

ARACHNIDA

Fig. 692

Paoroptes ovis —
female (Banks).

young female on being fertilized starts a burrow and thus a host
becomes infested in patches. About 100 species, 13 species being
American.

1. SARCOPTES Latreille. The first two pairs of legs end with
stalked suckers and in the male the fourth pair also; the others end
each with a long bristle ; mandibles chelate : in mammals,
burrowing in the skin; about 14 species, 6 American.
S. scabiei (DeGeer) (S. hominis Hering). Itch mite
(Fig. 691). Length of female .45 mm.; width .35 mm.;
male half as large; egg .14 mm. long: causes itch in
man and mange in hogs.

S. canis Gerlach. Mange mite. Length of female
.48 mm.; width .35 mm.; egg .17 mm. long: causes
mange in dogs, also in man.

S. cati Hering. Mange mite. Length of female
.25 mm.; width .2 mm.; egg .1 mm. long: causes mange
in cats.

2. PSOROPTES Gervais. Mandibles adapted for

piercing and not burrowing; stalks of leg suckers jointed: on the
surface of the skin of mammals, where they suck blood; 5 species.

P. ovis Hering. Scab mite (Fig. 692). Length of
female .60 mm.; width .40 mm.; egg .2 mm. long: on
sheep, cattle, and horses, causing scab; the eggs hatch
in 2 or 3 days and the young mature in 15 days; the
females live several weeks, laying numerous eggs; an
infection thus spreads very rapidly and may cause the
death of the host; common in the west.

3. CHORIOFTES Gervais. Females with suckers on
the fourth pair of legs: on the surface of the skin of
mammals, being restricted to certain parts of the
animal; 2 species.

0. communis Ziirn. Length of female .42 mm.; width .27 mm.:
causes local inflammation in the ears of dogs, cats, and rabbits.

4. CNEMIDOCOPTES Ftirst. Female without suckers on any of the
legs; mandibles chelate: on birds; 2 American species.

C. mutans Robin (Fig. 693). Length of female .45 mm.; width .35
mm. : the itch mite of fowls, causing scaly leg, but also appearing among
the feathers.

FAMILY 4. ANALGESIC AE. (DERMALEICHIDAE.)

Bird mites. Minute mites with an elongated body, a transversely
striated integument and often a transverse suture between the front 2

Fig. 693

Cnemidocoptes

mutans

(Banks).

ACAEINA

441

A, male

s pa

; B,

female.

and the back 2 pairs of legs; mandibles usually chelate and beneath an
epistome; legs with 5 joints and with a terminal sucker; in some genera
the male has a pair of clasping suckers and copulatory legs; abdomen
often bilobed behind: 31 genera and 400 species, which live upon birds,
feeding on the feathers, epidermal scales, etc., and usually not parasites;
24 American species.

1. ANALGES Nitzsch (Dermaleichus Koch). Body elongate, with the
hinder end rounded or pointed, and

never deeply bilobed; spines on the
first pair of legs; third pair of legs
of male larger than the others and
ending with claws and not suckers;
basal joint of first and second leg with
a backward projection: on singing
birds; 23 species, American.

A. passerinus (L.) (Fig. 694).
Length .45 mm. ; third pair of legs of
male enormously enlarged and used as
claspers: a European mite, found on
several species of American birds.

2. MEGNINIA Berlese. Third pair

of legs much larger than the fourth, with long spines on the terminal
joint; end of abdomen deeply bilobed in male: 42 species, 6 American.
M. columbae Buchholz. Length .33 mm.; each abdominal lobe in
male with 2 long and several small bristles; space between the lobes
filled in by a membrane: on domestic pigeons and other birds.

FAMILY 5. TYROGLYPHIDAE.*

Minute mites with an elongated body and a smooth integument; legs
alike in the two sexes; mandibles usually chelate; eyes and tracheae
absent; pedipalps close against the mouth parts; young born with 3
pairs of legs, in most forms passing through a stage called the hypopus,
in which it has 8 legs, but no mouth and no distinct mouth parts, but
with suckers on the under surface, which enable it to attach itself to
some insect or other animal which will transport it to some new local-
ity, where it completes its metamorphosis: about 47 species, 27 species
being American; they are not parasitic, but live on dried or decaying
animal and plant substances, but are often a pest to housekeepers, gar-
deners, and grocers, especially as the hypopus is often spread by
house flies.

* See "A Revision of the Tyroglyphidae of the United States," by N. Banks, Tech.
r. No. 13. Bur. of Ent., Dept. of Ag., Washington, 1906.

442 ARACHNIDA

1. TYROGLYPHUS Latreille. Body elliptical, with a suture between
the second and third pairs of legs; male with 2 suckers on each side of
the genital pore; mandibles chelate; a sucker at the
top of each foot: about 8 species.

T. siro (L.). Cheese mite. Length .6 mm.;
width .3 mm.; color whitish: in old cheese and sim-
ilar substances.

T. farinae (DeGeer) (Fig. 695). Length of
male .5 mm. ; of female .3 mm. ; color whitish : in flour,
grain, and stored foods; cosmopolitan; often a pest.
T. linterni Osborn. Similar to the above, but
smaller and with very long bristles extending back-
wards from the body: in mushrooms.

2. RHIZOGLYPHUS Claparede. Suture between

the second and third pair of legs; mandibles chelate; male with ventral
suckers; feet short, with stout claws and spines: 2 species.

R. hyacinth! (Boisduval). Bulb mite. Length .75 mm.: burrows
into the bulbs of cultivated plants, giving entrance to fungi and bac-
teria; often a pest in hot and green houses.

FAMILY 6. ORIBATIDAE.*

Horny or beetle mites. Body minute and divided into 2 parts by a
transverse suture; integument hard, with few hairs; a bristle, which is
often long, prominent, and club-shaped, and is called the pseudostig-
matic organ, arises from a depression near the hinder margin of the
cephalothorax on each side (Fig. 696,1); mouth parts and pedipalps
small and hidden beneath the head; mandibles chelate; claws 1 or 3;
the young are often very bizarre in shape: about 20 genera with over
300 species, which feed principally on vegetable or decaying animal mat-
ter and are not parasitic, but live in moss, grass, among decaying leaves,
in crevices of bark, etc.

Key to the genera of Oribatidae here described :

«! Abdomen with a pair of wins-like expansions 1. G ALUMNA

a» No such expansions.
6j Cephalothorax with a pair of dorso-lateral ridges.

<?! Body smooth 2. LIACABUS

ca Body rough ; cephalothorax and abdomen not distinctly separated.

3. SCUTOVEBTEX

62 No such ridges ; 3 claws on each leg.

dj Body flat, often rectangular 4. NOTHRUS

dz Abdomen very high with concentric rings 5. NEOLIODES

* See "On the Orlhatoidea of the United States," by N. Banks, Trans. Am. Ent.
Soc., Vol. 22, p. 1, 1895. "Oribatidae," by A. D. Michael, Das Tierreich, 1898. "New
Oribatidae from the United States," by N. Banks, Proc. Acad. Nat. Sci., Phila., 190G,
p. 490.

ACAEINA 443

1. GALTJMNA Heyden (Oribata Michael). Body shining black or
brown in color, with a pair of horizontal wing-like expansions at the side
of the abdomen and with 3 claws on each foot: 21 American species; in
moss 01 on trees.

G. pratensis Banks. Length .7 mm. ; yellowish-brown in color : often
common in meadows.

G. emarginata Banks. Body dark
reddish-brown in color and .9 mm. long;
wing emarginate below: often common
in moss, or on the ground.

2. LIACARUS Michael. Body smooth,
last 3 pairs of legs inserted under the

body, each ending with 3 claws : 9 Amer- mg Q9Q-Ti a oar us nitidus

ican species. (Banks) ; pseudostigmatic organ.

L. nitidus Banks (Fig. 696). Body 1 mm. long, subspherical, shining

dark reddish-brown or black: under fallen leaves, stones, etc.; common.

3. SCUTOVERTEX Michael. Divisions between cephalothorax and
abdomen not very distinct; body rough and sculptured: 2 American
species.

S. marinus Banks. Paired bristles on cephalothorax wanting: on
the rocks between tide marks on the Atlantic seashore.

4. NOTHRTTS Koch. Body rough and more or
less rectangular; back flat or concave; legs short,
thick, and rough, ending with 3 claws: 20 species,
which live in moss, on bark of trees, or on rocks, 7
American.

N. excisus Banks. Length .7 mm.; most of the
hairs serrated: on the bark of spruce trees; New
York state.

Fig. 097— Neoiwdes N. rugulosus Banks. Body dark brown and

concentnca
(Banks). very rough, appearing like a piece of dirt: common

under loose bark.

5. NEOLIODES Berlese. Abdomen convex and very high, with con-
centric rings; feet with 3 claws: 3 species.

N. concentrica (Say) (Fig. 697). Body black, 1.5 mm. long; color
brown: on bark of trees; Europe.

FAMILY 7. GAMASIDAE.

Scavenger mites. Body broad, with short legs; eyes absent; man-
dibles usually ehelate, and beneath them is a bifid hypostome; pedipalps
5-jointed and prominent ; legs 6-jointed and ending with 2 claws or with
a sucker; tracheae present, a pair of spiracles being located above the

444

AEACHNIDA

fourth legs, each being surrounded by a chitinous ring called the stig-
nial plate or peritrerne, which usually extends forwards a long distance;
the young mostly born with 3 pairs of legs : numerous species and about
18 American genera, some of the species being parasitic on insects, espe-
cially beetles, and on vertebrates, while many species use insects for
transportation; some lead a free life in moss and on the ground.
Key to the genera of Gamasidae here described:

Oi Free-living or attached to insects and rarely to vertebrates.
&! First pair of legs inserted on one side of the inouth opening.

G! Leg with one claw ; female genital plate triangular 1. GAMASUS

c2 Leg 1 without claws ; leg 2 thickened 2. MACBOCIIELES

&2 First pair of legs inserted in the same opening as the mouth parts.

4. UROPODA
aa Parasitic on birds 3. DEBMANYSSUS

1. GAMASUS Latreille. Body usually flattened, with or without a
transverse dorsal suture; female genital plate triangular; male genital
pore on anterior margin of sternal plate: about 10 American species,
which live on the ground, among fallen leaves, etc., or on insects.

G. coleoptorum (L.). Length .6 mm.; transverse dorsal suture pres-
ent; 4 large spines projecting from the hinder end; anterior end trian-
gular; first pair of legs with sucking discs: on beetles.

2. MACROCHELES Latreille. Body elongate, with
no transverse dorsal suture; second leg enlarged, in
male curved and armed with teeth; mandibles very
thick; male genital pore on anterior margin of
sternal plate; first pair of legs without claws:
several species.

M. mcestus Banks. Body reddish-brown and 1
mm. long, with 8 rows of clavate hairs above and a
few on the hinder margin: common in ants* nests.

3. DEEMANYSSUS Duges. Bird mites. Body
elongate and not distinctly constricted; hind legs
not reaching the hinder end; mandibles chelate in
male, long and piercing in female : parasitic on birds,
especially domesticated ones; 1 American species.

D. gallinae (DeGeer). Chicken mite (Fig. 698). Body .7 mm.
long, .4 mm. wide, pear-shaped and flat and reddish in color : the mites hide
during the day in the coop and at night attack the fowls and suck their
blood, and are often a serious pest; they frequently attack dogs, cats,
and horses, as well as man.

4. UROPODA Latreille. Body ovoid, with depressions on the under
side for the reception of the legs; mandibles very long and slender, and
chelate : on beetles, ants, and other insects ; some are parasitic, but most

Fig. 698 — Dermanys-

sus gallinae

(Banks).

ACAEINA 445

of the species use the insects only for transportation, being young ani-
mals in the nymphal stage which attach themselves by a pedicel of
excrement: as adults they live on the ground among fallen leaves, and
in similar places; several species.

5. U. vegitans (DeGeer) (Fig. 699). Body
arched, smooth, brownish in color, about 1 mm.
long: common.

FAMILY 8. AKGASIDAE.

Ticks. No scutum, as in the Ixodidae; stigmal
plate between legs 3 and 4: 16 American species,
which are nocturnal parasites of domestic birds.

ARGAS Latreille. With the characters of the family: about 10
species.

A. persicus Fischer (A. miniatus Koch). The Miana bug. Body
oval in shape, 5 mm. long in the male and 10 mm. in the female and
brown in color: often a dangerous parasite of chickens from Florida to
California; cosmopolitan; in western Asia it bites persons and is much
feared.

FAMILY 9. IXODIDAE.*

Ticks. Body often large, and covered with a leathery integument
capable of great distention in the female, with prominent, slender legs
and beak-like mouth parts; anterior dorsal surface covered with a horny
shield, the scutum (Fig. 700, B), which in the male extends over the
entire back; articulating with the anterior margin of this is the head or
capitulum, on which in the female are 2 pitted spots; head bears the
short, thick, 3 or 4-jointed pedipalps at the sides and in the middle,
the elongated beak or rostrum, which is made up of the 2 mandibular
sheaths above, and the toothed hypostome or under lip beneath, with
the 2 mandibles between, the latter organs being toothed at the tip;
eyes present or not; tracheae present, the spiracles being just behind
the last pair of legs, each surrounded by a stigmal plate or peritreme
(Fig. 700, C) ; legs 6-jointed, ending with 2 claws and a pad, the foot
of first pair also bearing a sense organ called Haller's organ: parasitic
on mammals, birds, and reptiles; the female, when gorged with blood,
falls to the ground to lay her eggs; the young ticks, which have but
6 legs at first, usually ascend some plant and are brushed off by a
passing vertebrate which can set as a host; 250 species, about 35
American.

* See "The Cattle Ticks of the United States," by D. C. Salmon and C. W. Stiles,
Rep. Bureau of An. Ind., U. S. Dept. of Ag., 1902, p. 380. "Ixodidae," by L. G.
Neuman, Das Tierreich, 1911.

446 ARACHNIDA

Key to the genera of Ixodidae here described:

a: Pedipalps much longer than broad.

6j Eyes absent 1. IXODES

62 Eyes present 2. AMBLYOMMA

a2 Pedipalps very short and thick.

&! Stigmal plate round 3. MARGAROPUS

&2 Stigmal plate comma-shaped 4. DERMACENTOB

1. IXODES Latreille. Eyes absent; pedipalps and beak long and of
the same length ; anal groove surrounds anus anteriorly and is open pos-
teriorly : over 50 species, about 14 in America.

1. ricinus (L.). The castor bean tick. Body oval, in male 3.5 mm.
long and 2 mm. broad and high ; in female 4 mm. to 11 mm. long, accord-
ing to the amount of blood it has sucked, and brown or yellow in color ;

at the base of the
first pair of legs in
the female is a
strong median
spine: cosmopoli-
tan; often common
on domestic ani-
mals, rabbits, etc.,

Fig. 700 — Amllyomma americanum (Hooker). A, dorsal also on man.
aspect of female; B, the scutum; C, stigmal plate. 1, T _„, _ •_

first leg; 2, pedipalps ; 3, rostrum. »• SCapUlailS

Say. Body 3 to 6

mm. long and 2 mm. broad, with a dark brown shield: common in the
southern states on all kinds of wild animals, dogs, and cattle.

2. AMBLYOMMA Koch. Eyes present; anal groove surrounds anus
posteriorly and is open anteriorly; pedipalps and beak long: 86 species,
4 American.

A. americanum (L.). Lone star tick (Fig. 700). Body 4 mm. long,
3 mm. wide; the gravid female may measure 12 mm. in length and 8
mm. breadth; color of male brown, of female bluish, with a brown
scutum, the hinder end of which has a conspicuous yellowish spot,
which gives the animal its popular name: often common on cattle, also
on man.

3. MARGAROPUS Karsch (Boophilus Curtice). Eyes present, often
indistinct; pedipalps short and broad, with the second and third joints
extended laterally into sharp points; spiracles round: 2 species, 1
American.

M. annulatus* (Say) (M. bovis Riley). Texas cattle tick (Fig. 701).
Body oval and 2.30 mm. long, and brown in color in male, and elliptical

* See "Texas Fever," etc., by J. R. Mohler. Bull. 78, Bur. Animal Industry,
Dept. Ag. 1905.

ACAttlNA

447

or more or less rectangular and up to 13 mm. long and yellowish or
slate-color in the female: southern states, on cattle, often very common,
causing the destructive Texas fever, the disease being caused by the
inoculation of the cattle by the tick of Babesia bigemina, a sporozoan
blood parasite (see page 47).

4. DERMACENTOR Koch. Eyes present; pedipalps short and broad;
stigmal plate comma-shaped; scutum partially white or yellow: 20
species, about 4 American.

D. variabilis (Say) (D. electus Koch). Dog tick (Fig. 702). Body
oval or rectangular; scutum reddish-brown with white spots; stigmal

Fig. 701

Fig. 702

ifig. 701 — Margaropm annulatus (Banks). A, female; B, male. Fig. 702 — Derma-
centor variabilis — male (Banks).

plate finely punctate; color brown, variegated; length of replete female
15 mm.; breadth 9 mm.: on domestic animals and man, often abundant
in the eastern and central states, being the tick that often attaches to
persons in the woods.

D. venustus* Banks. The Rocky Mountain spotted- fever tick. Body
an elongated oval and 2 to 6 mm. long in the male and about 15 mm.
long in the female and reddish-brown in color: the northwestern states;
the larvae live on small mammals and the adults on the larger domestic
animals and man; the cause of a very dangerous fever which is the result
of the inoculation by the tick of a sporozoan blood parasite, Babesia
hominis (see page 47).

FAMILY 10. HYDBACHNIDAE.f

Fresh-water mites. Body usually ovoid or spherical and sometimes
of large size, and often brightly colored; 1 or 2 pairs of eyes present;

* See "A Zoological Investigation into the Cause, Transmission, and Source of
Rocky Mountain Spotted Fever," by C. W. Stiles, Bull. No. 20, Hyg. Lab., Treasury
Department, Washington, 1905.

t See "Nordamerikanische Hydrachniden," by F. Koenike, Abh. d. natur. Ver. zu
Bremen, Vol. 13, p. 167, 1895. "Deutschlands Hydrachniden," by R. Piersig, Blbl.
Zool. No. 22, 1897 to 1900. "Hydrachnidae und Halacaridae," by R. Piersig und

448 ARACHNIDA

mandibles with a terminal claw; pedipalps 5-jointed and usually long,
the terminal claw being sometimes bent down to form a grasping organ;
legs usually 5-jointed, with or without swimming hairs, and joined to
body by prominent coxal plates (Fig. 705, 1) ; a pair of spiracles on the
dorsal side of the rostrum; genital pore surrounded by a plate and
usually near the center of the body; numerous minute suckers often on
each side of the genital pore; eggs laid on plants, stones, etc.; young
born with 6 legs and usually go through a complex metamorphosis, often
attaching themselves to aquatic insects : about 70 genera and 500 species,
most of which live in fresh water, a few being found in brackish water
or in the sea, and the genus Unionicola being parasitic in rnollusks; about
100 American spe«ies; 5 subfamilies.

Key to the subfamilies of Hydrachnidae :

<LI Large red mites with 4 eyes close together on a plate.

&! Eye plate long and narrow 1. LiMNOCHARlNAE

6a Eye plate short, broad and paired 2. EYLAINAE

C2 Eyes not close together on a plate, but far apart.
&! Pedipalps chelate.

d Mandibles 1-jointed, straight and needle-like 3. HYDRACHNINAE

c2 Mandibles 2-jointed, the terminal joint a curved hook. 4. HYDRYPHANTINAE
63 Pedipalps not chelate 5. HYGROBATINAE

SUBFAMILY 1. LIMNOCHAEINAE.

Body very soft, variable in form, red in color; eyes 4, near together
on a long lanceolate plate: 2 genera.

LIMNOCHARES Latreille. Body rectangular; legs without swimming
hairs, but with spines, and in 2 widely separated groups of 2 each: the
animals do not swim but walk slowly over the mud and plants in the
water; 2 species.

L. aquatica (L.) (Fig. 703). Body red, 4 mm. long: on the bottom
of ponds; cosmopolitan and common; larvae attached to water skaters
(Hydrometridae) .

SUBFAMILY 2. EYLAINAE.

Body soft, regular in outline, red in color ; eyes 4, near together on a
paired plate: 2 genera.

EYLAIS Latreille. Body oval, legs long, with swimming hairs,
rather close together; genital pore between the first 2 pairs: 35 species,
the larvae of which have been found on mosquitoes; 3 American species,
which are rapid swimmers.

H. Lohmann, Das Tierreich, 1901. "A Review of the Genera of the Water Mites," by
R. H. Wolcott, Trans. Am. Mic. Soc., Vol. 26, p. 161, 1905. "Die Susswasserfauna
Deutschlands, Heft 12, Araneae und Acarina," by F. Koenike, 1909.

ACAE1NA

449

E. extendens (0. F. Miiller) (Fig. 704). Body red, 4 mm. long: in
ponds; cosmopolitan and common.

SUBFAMILY 3. HYDRACHNINAE.

Body soft, sometimes with chitinous plates; 4 eyes, 2 on each side
and sometimes another in the middle ; rostrum usually elongate, forming
a snout, at the end of which is the mouth ; mandibles 1-jointed, long and
needle-like; pedipalps chelate: 2 genera.

HYDRACHNA O. F. Miiller. Body oval or round; legs rather short,
the last 3 pairs with swimming hairs; genital pore between the last 2

Fig. 703

Fig. 704

Fig. 705

Fig. 703 — Limnochares aquatica (Banks). A, ventral aspect; B, dorsal eye plate.
Fig. 704 — EylaAs extendens (Wolcott). A, ventral aspect; B, dorsal eye plate. Fig.
705 — Hydrachna geographica (Wolcott). 1, coxal plates; 2, genital plate.

pairs of legs; the larvae attach themselves to aquatic insects: about 33
species, 8 American.

H. geographica (Mull.) (Fig. 705). Body oval, arched, dark red in
color with dark spots on the back; length 7 mm.: often common;
cosmopolitan.

SUBFAMILY 4. HYDRYPHANTINAE.

Body soft, sometimes with chitinous plates, and red or brownish in
color; 1 or 2 eyes on each side and sometimes a median eye; coxal plates
in 4 groups : the larva leaves the water and is parasitic on aerial insects,
returning to the water to complete its transformation; 13 genera.

Key to the genera of Hydryphantinae here described :

«! One eye on each side contained in a chitinous capsule, and a median eye.

61 Swimming hairs on legs 1. HYDBYPHANTES

62 No swimming hairs 2. THYAS

Oj Two eyes on each side and no median eye 3. DIPLODONTUS

1. HYDEYPHANTES Koch. Swimming hairs on the last 3 pairs of
legs; median eye surrounded by a chitinous plate, but no other chitinous
plates on the dorsal surface : 17 species.

H. ruber (DeGeer) (Fig. 706). Body 2 mm. long, red in color, often
tending to be dark: in wood ponds, especially in the springtime.

450

ARACHNIDA

2. THYAS Koch. Like the above but with no swimming hairs on the
legs; body flattened: 7 species, 2 American, the larvae of which leave
the water and attach themselves to aerial insects.

T. stolli Koenike. Body 1.2 mm. long, oval and red in color; legs

with numerous bristles.

3. DIPLODONTUS D u g e s.
Body oval or round; eyes 2 on
a side ; no median eye ; legs with
swimming hairs; genital plate
heart-shaped: 3 species.

D. despiciens (0. F. Miiller)
(Fig. 707). Body 2 mm. long,
red in color with an indistinct
darker dorsal spot, and also
covered with papillae; larva on
aerial insects: common.

Fig. 706

Fig. 707

Fig. 706 — Hydryphantes ruber (Wolcott).
1, coxal plates ; 2, genital plate. Fig. 707 —
Diplodontus despiciens (Wolcott). A, ven-
tral aspect of male; B, pedipalp of female.

SUBFAMILY 5. HYGROBATINAE.

Body compact, surface smooth or with fine parallel lines, sometimes
with chitinous plates ; eyes of the 2 sides distant from each other, either
1 or 2 eyes being on a side and never in a capsule; no median eye;
pedipalp not chelate, or rarely so; coxal plates large, sometimes cover-
ing the whole ventral surface; the larva (except in Unionicola) attached
to water insects : 53 genera, 2 genera with about 4 species being found in
the sea off the coast of France.

Key to the genera of Hygrobatinae here described :

d Pedipalps not chelate.
&! Coxal plates not fused together.

Cj, Coxal plates in 3 groups 1. HYGBOBATES

C3 Coxal plates in 4 groups.
di Fourth leg ending with a claw and not a bristle.

€i Free-swimming; fourth joint of pedipalp with 2 papillae 2. PiONA

ea Parasitic in mussels 3. UNIONICOLA

dt Fourth leg ending with a long bristle 4. LIMNESIA

&a Coxal plates fused into a single plate 5. KOENIKEA

o, Pedipalps chelate ; body of male with a posterior appendix ... 6. ABBHENUBUS

1. HYGROBATES Koch. Body ovoid; coxal plates of female in 3
groups; no swimming hairs present; genital pore midway between the
hinder coxal plates and the hinder end of the body with 3 or more suckers
on each side : 11 species, 4 American.

H. longipalpis (Hermann) (Fig. 708). Body 2.5 mm. long and yel-
low in color, very convex dorsally; pedipalps almost half as long as the
body: cosmopolitan.

ACARINA

451

Fig. 708 — Hygro-

bates longipalpis

(Wolcott).

2. FIONA* Koch (Curvipes Koenike). Fourth joint of pedipalp usu-
ally with 2 papillae; legs all with swimming hairs; genital pore close
behind the hind coxal plates: 19 American species, among the largest
and most active hydrachnids.

P. spinulosa (Wolcott) (Fig. 709). Body broadly
elliptical and about .5 mm. long, being one of the
smallest of the genus and nearly transparent, with
patches of dark brown and a spot between the large
eyes; coxal plates close together and covering most of
the ventral surface; legs long and with few spines; 20
to 30 suckers on each side of genital pore: widely
distributed and common in central states.

3. UNIONICOLAJ Haldeman (Atax Fabricius). Body

ovoid or round ; genital opening at the hinder end of body, the plate on
each side of the opening bearing many minute suckers; pedipalps long,
in the parasitic forms thick ; first pair of legs usually thick, in the non-
parasitic species with long, movable spines ; third and fourth pair of legs
with swimming hairs: 16 American species, most of
which are parasitic either in youth or permanently,
on the gills of Unionidae and occasionally other
mollusks.

U. ypsilophora (Bonz). Body ovoid, about 1.3
mm. long, yellowish-white in color with large brown
or black spots, and a yellow Y-shaped mark on the
back; about 20 minute suckers on each side of gen-
ital pore; first pair of legs not thicker than the
others: widely distributed and common in the
eastern and central states, occurring, with rare exceptions, in species of
Anodonta; Europe.

U. fossulata (Koenike). Body ovoid, about 1.4 mm. long; 5 suckers
on each side of genital pore; first pair of legs not so thick as the pedi-
palps : central states, common, occurring, with rare exceptions, in species
of Unio.

4. LiMNESiAj Koch. Body ovoid; fourth pair of legs without the
terminal claws, but with a bristle at the tip; pedipalps long with the
second joints thickened ; 3 or 4 suckers on each side of the genital pore ;
4 eyes: 6 American species.

* See "The North American Species of Curvipes," by R. H. Wolcott, Trans. Am.
Mic. Soc., Vol. 23, p. 201, 1902.

t See "On the North American Species of the Genus Atax Fabr.," by R. H. Wol-
cott, Trans. Am. Mic. Soc., Vol. 20, p. 193, 1899.

t See "On the North American Species of Limnesia," by R. H. Wolcott, Trans.
Am. Mic. Soc., Vol. 24, p. 85, 1903.

Fig. 709

Fiona spinulosa

(Wolcott).

452 AEACHN1DA

L. histrionica (Hermann) (Fig. 710). Length of female 2 mm.;
breadth 1.7 mm. ; male half as large ; color variable but usually yellowish
with dark patches and red spots on the back; legs bright green; eyes
red ; body marked with faint wavy lines ; pedipalps very long and thick :
very common over the whole country; Europe.

5. KOENIKEA* Wolcott. Body round, flat or concave on dorsal sur-
face, with a long curved rostrum in the female; coxal plates of male
fused into a single plate, and in the female into 2 plates; legs with

Fig. 710 Fig. 711

710 — Limnesia histrionica (Wolcott). Fig. 711 — Arrhenurus america
shall) . A, ventral aspect of male ; B, ventral aspect of female.

swimming hairs; numerous minute suckers on each side of the genital
pore: 1 species.

K. concava Wolcott. Body .67 mm. long; eyes 2, widely sepa-
rated: common and widely distributed over the eastern and central
states.

6. ARRHENURirsf Duges. Integument very hard and porous; back
with a circular furrow enclosing the dorsal shield ; female oval in shape ;
male with the hinder end very much prolonged, forming an appendix4,
eyes widely separated ; coxal plates of the first 2 pairs of legs contiguous ;
also those of the last 2 pairs; pedipalps chelate: 150 species, 50
American.

A. marshalli Piersig. Body of male 1 mm. long with the appendix
very long, cylindrical and constricted at the base; female .8 mm. long
and oval; color blue-green, occasionally orange: cosmopolitan and com-
mon, usually the most abundant of the genus.

A. americanus Ruth Marshall (Fig. 711). Male .92 mm. long;
appendix widest at hinder end; color greenish, tinged with red; female
1.12 mm. long and ovate in form : abundant in the Middle West.

* See "New Genera and Species of North American Hydrachnldae," by R. H.
Wolcott, Trans. Am. Mic. Soc., Vol. 21, p. 189, 1900.

t See "The Arrhenuri of the United States," by Ruth Marshall, Trans. Am. Mic.
Soc., Vol. 22, p. 85, 1908.

ACARINA 453

FAMILY 11. HALACABIDAE.*

Salt-water mites. Body rather elongate, usually with a suture
between the 2 pairs of legs ; rostrum often large ; 3 eyes usually present ;
no tracheae; no swimming hairs on legs: about 10 genera and 70 species
known; the animals are found crawling slowly over algae in the sea,
being vegetal feeders; the young feed on the eggs of copepods and are
attached to various animals; 1 fresh- water species.

HALACARUS Gosse (Thalassarachna Packard). Pedipalps 4-jointed,
long, free, and distant from each other; body convex and rather elon-
gate; first leg but little thicker than the second: about 41 species, 1 in
fresh water.

H. verrilli (Packard). Body ovoid with a transverse suture, just
back of which is a pair of black eyes ; color dark, rostrum conical ; man-
dibles slender and almost as long as the pedipalps; length
1.75 mm.: on hydroids off the coast of Maine.

FAMILY 12. BDELLIDAE.

Snout mites (Fig. 712). Body elongate, with a trans-
verse suture between the second and third pairs of legs;
mandibles very long and large; pedipalps long and slen-
der ; spiracles at the base of the rostrum : about 13 Amer-
ican species, which are active predacious animals living
in moss, rotten wood, and similar places, and can move
backwards as well as forwards.

BDELLA Latreille. Palps used like antennae and Fig- 712
elbowed, the last joint bearing 2 or more long bristles; A (Banks™."6
mandibles chelate: about 10 American species.

B. marina Packard. Body red in color and 2 mm. long; last joint of
pedipalp not widened at tip, hairs at end not as long as the joint ; many
bristles on body: along Atlantic seaboard.

B. cardinalis Banks. Body red in color and 1.2 mm. long; last joint
of pedipalp widened at tip, and with hair at end much longer than joint ;
body with about 20 bristles: in moss and on the ground.

FAMILY 13. TROMBIDIIDAE.

Harvest mites. Body globular or elongate, red in color, and hairy,
usually with a transverse suture between the second and third legs;
mandibles chelate; eyes often stalked (Fig. 713) ; legs end with 2 claws;
pedipalps 5-jointed; spiracles at the base of the mandibles; the larvae

* See "Hydrachnidae und Halacaridae," by R. Pierslg and H. Lohrnann, Das
Tierreich, 1901.

454 AEACHN1DA

have 3 pairs of legs and are parasitic on insects, spiders, etc., Trombidium
being very common on house flies in the autumn, certain species, espe-
cially in the southern states, attacking man: about 4 American genera
with 30 species, none of which are parasitic as adults.

TROMBIDIUM Fabricius. Mandibles chelate; eyes stalked: about 12
American species, which are found on plants and on the ground, and
walk slowly.

T. sericeum Say. Body broadest in front, densely covered with short
silken hair; eyes 2 and stalked and white: the commonest species in the
eastern states, living on trees and on the ground.

T. locustarum Riley
(Fig. 713). Body elon-
gate, red, tapering be-
hind ; male with a
sunken elliptical area
above; 4 to 5 mm. long:
on ground, young on

Fig. 713— Trombidium locustarum (Banks). A, ventral grasshoppers,
aspect of male ; B, eye-stalks ; C, a larva.

FAMILY 14. RHYNCHOLOPHIDAE.

Like the Trombidiidae, but with piercing mandibles and sessile eyes;
a mid-dorsal line or furrow on cephalothorax : 3 American genera, the
individuals of which walk rapidly.

RHYNCHOLOFHUS Duges. Mandibles slender, needle-like, and retrac-
tile; eyes 4 and sessile; legs long: 15 American species, which feed on
small insects, such as aphids and scales, and run rapidly.

R. simplex Banks. Body red, 2.2 nun. long, with some erect bristles
on the body and among them many fine hairs; all legs long, hind pair
longer than the body: on dry ground.

R. maculatus Banks (Fig. 714). Body with red spine-like hairs,
leaving several smooth white patches; legs short, hind pair no longer
than body; length 1.5 mm.: on ground and plants.

FAMILY 15. TETBANYCHIDAE.*

Red spiders. Body oval, with a few bristles arranged in about 4
rows, and with a transverse suture between the second and third pairs of
legs, and red in color; 2 or 4 eyes, without stalks; pedipalps 4-jointed,
the penultimate joint usually with a strong claw; mandibles with their
basal portions fused and tips long and flexible, and fitted for piercing

* See "The Red Spiders of the United States," by N. Banks, Bull. No. 8, Tech.
Ser., Div. Ent., U. S. Dept. Agr., 1900.

LINGUATULTDA 455

the plant tissues, on the juices of which the animal usually lives: on
plants and the ground, often a pest in greenhouses; about 6 American
genera, with 20 species.

1. TETRANYCHUS Dufour. Pedipalps short, ending with a thumb-
like projection; the animals are able to spin a web, by means of which
they fasten the minute red eggs to leaves; first pair of legs longer than
the body: about 14 American species.

Fig. 714 Fig. 715 Fig. 716

Fig. 714 — Rhyncholophus macuJatus (Banks). Fig. 715 — Tetranychus bimaculatua
(Banks). Fig. 716 — Bryobia prate nsis (Banks).

T. bimaculatus* Harvey (T. cucumeris Boisduval) (Fig. 715). But
1 claw on each foot, which splits into 4 near the tip; color and size
variable; color usually red, but sometimes yellowish with black dots:
often common on vegetables and cultivated flowers, both in greenhouses
and out of doors.

2. BRYOBIA Koch. Body with scale-like hairs above: 1 American
species.

B. pratensis Garman (Fig. 716). The clover mite. Body red with
4 scale-like hairs projecting in front; first pair of legs longer than the
others : often numerous on clover and fruit trees ; eggs red, on fruit trees
in winter; they often hibernate in houses, and may become a nuisance.

ORDER 9. LINGUATULIDA.J

Worm-like arachnids (Fig. 717, A), in which the abdomen is very
much elongated and composed of a large number of short rings, which

* See "The Common Red Spider (Tetranychus bimaculatus) ," etc., by F. H.
Chittenden, Cir. 29, Div. of Ent., U. S. Dept. of Agr., 1909.

t See "Contribution to Helminthology," by J. Leidy, Proc. Acad. Nat. Sci., Phila.,
Vol. 5, p. 96. "A Synopsis of Entozoa," etc., by the same, same, 1856, p. 42.
"Description of Pentastomum prob.," by the same, same, 1884, p. 140. "Bau u.
Entwick. von Pentastomum," etc., by C. W. Stiles, Zeit. f. Wiss. Zool., Bd. 52, 1891.
"An Attempt to Revise the Family Linguatulidae," by A. E. Shipley, Arch, de
Parasit., Vol. 1, p. 52, 1898.

456

ARACHNIDA

are not, however, equivalent to somites. The cephalothorax is very short
and bears on its ventral side 2 pairs of hook-like retractile claws. Excre-
tory, respiratory, circulatory, and sense organs are all absent. The diges-
tive tract is a straight tube. The nervous system consists of a sub-
O3sophageal ganglion and a circumoesophageal ring. The sexes are
separate, the male genital pore being near the mouth, the female near
the anus at the hinder end. The linguatulids live as parasites in the air
passages and also in the body cavity of certain mammals and reptiles.
f . 9 The eggs reach the outside world together with the

discharges of the host and must be swallowed by a
mouse, rabbit, or other small animal in order to de-
velop. The larva (Fig. 717, B), hatching in the stomach
of this intermediate host, is quite mite-like in appear-
ance and has 2 pairs of legs and boring mouth parts.
It makes its way into the liver, peritoneum, or other
organ, where it encapsules itself and here undergoes
the greater part of its metamorphosis and attains the
form of the adult, except that it
has a circle of spines around each
ring and is not sexually mature.
It may then leave its cyst and
migrate through the tissues of the
host, and may reenycst in some
other locality. If the intermedi-
ate host is then eaten by the final
host, the parasite passes into its
final resting place in the latter.
It may, for instance, pass directly
from the mouth into the nasal
passages, or it may migrate from
the stomach or intestine through
the intestinal wall into the lungs, or air passages, where it becomes
mature.

The linguatulids were formally classed among the worms, but the
resemblance of the body of the adult to that of eriophyid mites and of
the larva to the short-bodied mites, as well as their voluminous body
cavity and striated muscle fibres, have caused them to be placed among
the Arachnida. Both the adult and larva are occasionally found in man.
The order contains 3 genera and about 26 species.
Key to the genera of Linguatulida here described :

d! Body flat 1. LINGUATULA

a, Body cylindrical 2. POROCEPHALUS

Fig. 717 — Porocephalus crotali. A, dia-
gram showing anatomy ; B, a larva (Stiles).
1, mouth ; 2, hooks ; 3, genital pore ; 4, tes-
tis ; 5, intestine ; 6, sperm duct ; 7, anus.

TAKDIGRADA 457

1. LINGUATULA Frolich (Pentastomum Rudolphi). Body flat, with
a convex back and scalloped edges; eephalothorax usually not so broad
as the abdomen: 4 species.

L. taenioides (Lamarck). Body lanceolate; number of abdominal
rings about 90; length of female 85 mm.; width 10 mm.; length of male
20 mm.; width 3 mm.: the adult occurs in the frontal sinus of the dog
and horse and in the nasal cavities of the dog, horse, wolf, fox, goat, and
man; the larvae form (P. denticulatum) is 5 mm. long and 1.5 mm. wide
and occurs in the liver, lungs, and other organs of the cat, horse, rabbit,
rat, and other animals.

2. POROCEPHALUS Humboldt (Pentastomum Rudolphi). Body cylin-
drical; head usually, but not always, as wide as the abdomen: 21 species.

P. crotali Humb. (P. proboscideum Rud.) (Fig. 717). Body sub-
clavate; number of rings about 40; length of female 80 mm.; width 7
mm. ; length of male 56 mm. ; width 5 mm. : the adult occurs in the lungs
and body cavity of the rattlesnake and boa constrictor and a few other
animals; the larva (P. subcylindricus) occurs in the liver and body cavity
of the mouse and other small animals.

ORDER 10. TARDIGRADA.*

Water bears. Minute, usually aquatic animals with a cylindrical
unsegmented body, tapering slightly at both ends and with 4 pairs of
short legs, each ending with several claws, the last pair of legs being at
the hinder end of the body. No mouth parts are present, but a pair of
retractile teeth project from the mouth, beside which are the openings of
a pair of large salivary glands. Respiratory, excretory, and circulatory
organs are wanting. The digestive tract is a straight tube. The nerv-
ous system consists of a brain and 4 pairs of ventral ganglia; a pair of
eyes are usually present. The animals are hermaphroditic, the single
gonad opening into the cloaca ; the eggs are usually laid while the female
is moulting and the young develop in the empty skin.

The tardigrads are microscopic animals which are found among
aquatic vegetation and at the bottom of standing water, and also in moss
and other damp places, where they live on both vegetal and animal food.
They possess the ability to exist in a desiccated condition for several
years. The systematic position of these animals is very obscure. They
are usually placed near the mites among arachnids, because of their 4
pairs of legs and small unsegmented body, but their simple structure,
primitive legs, lack of mouth parts, and unstriated muscle fibres seem to

* See "Beitrage zur Naturgeschichte der Tardigarden," by L. H. Plate, Zool.
Jahrb., Abt. fur. Anat., Bd. 3, 1888.

458 ARACHNIDA

indicate that they are the most primitive of all arthropods. The order
contains about 6 genera and 50 species.

1. MACROBIOTTJS S. Schultze. Claws all or in part double and often
of different lengths; dark but never red pigment in the integument; no
feelers or cirri on head; a pair of strong teeth in the
mouth: 7 species.

M. hufelandi Schul. (Fig. 718). Each leg ends
with 2 double claws, the 2 sides of each pair being
firmly fused and one of them with a small branch
claw; length .7 mm.: common in fresh-water ponds.

2. ECHINISCUS S. Schultze. Claws all single and
not double, several being on a leg, all of the same
length; 2 red eyes present, also short cirri or feelers
beside the mouth on each side; 2 long teeth in the
mouth; the cuticula, jointed on the back, often has red
spots in it, and usually spines or hairs project from it :
about 13 species in both fresh and salt water.
E. sigismundi Schul. Third leg with a short spur; each leg ends
with about 8 claws; 2 sharp palps on each side beside the mouth, and 2
more beside the eye ; length .2 mm. : marine, among algae.

E. testudo Doyere. Body reddish in color and opaque; length .3
mm.: often in the moss of damp roofs.

ORDER 11. PYCNOGONIDA.* (PANTOPODA.)

Sea spiders. Marine arachnids, usually of small size, in which the
body consists of a large segmented cephalothorax and a minute rudimen-
tary abdomen (Fig. 719). Seven pairs of appendages are present, of
which the hinder four pairs are the very long, 9-jointed legs, which seem
to have developed at the expense of the trunk, as it is reduced to the
smallest proportions. The three forward pairs of appendages are the
long chelate mandibles, the slender pedipalps, and the slender ovigerous
legs, which are wanting in the females of certain species. The cephalo-
thorax is made up of the following five segments: the anterior more or
less cylindrical rostrum, at the front end of which is the mouth; a large
segment bearing the mandibles, the pedipalps, the ovigerous legs and the
first pair of walking legs, as well as 4 eyes ; and 3 segments, each bearing
a pair of legs. The digestive tract is complex in structure, long diver-

* See "The Pycnogonida of New England and Adjacent Waters," by E. B. Wilson,
Rep. TJ. S. Fish. Com. for 1878, p. 463, 1880. "A Contribution to the Embryology
and Phylogeny of the Pycnogonids," by T. H. Morgan, Studies Biol. Lab., Johns Hop.
Univ., Vol. 5, 1890. "Notes on the Habits of Pycnogonids," by L. J. Cole, Biol.
Bull., Vol. 2, p. 195, 1901. "Pycnogonida," by D. W. Thompson, Camb. Nat. Hist.,
Vol. 4, p. 500, 1909.

PYCNOGONIDAE 459

ticula extending off from the intestine into the legs and the mandibles
almost to their tips. The anus at the end of the abdomen. No respira-
tory or excretory organs are present. The nervous system consists of a
brain and a ventral nerve chord with five pairs of ganglia. The sexes
are separate, the gonads consisting of a pair of testes or ovaries which
are fused together in the adult and much branched. The genital pores are
situated in most cases on the second segment of the last two legs in the
male and of all the legs in the female. The eggs are carried by the males
on the ovigerous legs and hatch usually into six-legged larvae, which go
through a metamorphosis. The larva of Pallene resembles the adult at
hatching.

The pycnogonids live among marine algae and on hydroids, and vary
in length from a millimeter to a number of centimeters. Their system-
atic position is very obscure, but they are usually grouped with the
arachnids. They differ from these animals, however, in having seven
pairs of appendages, a difficulty which may be overcome by considering
the last pair of legs abdominal and homologizing them with the first pair
of embryonic abdominal legs, which characterize the other arachnids.
The animals have been classed with the Crustacea and the larva compared
with the nauplius, to which it has a superficial resemblance. They have
also been derived from a primitive annelid ancestor and the characteristic
larva compared with a modified annelid larva. The order contains about
9 families and over 200 species.

Key to the families of Pycnogonida here described:

ox Mandibles wanting 1. PYCNOGONIDAE

aa Mandibles present.

6t Mandibles not chelate 2. AMMOTHEIDAE

&2 Mandibles chelate.

ct Pedipalps wanting 3. PALLENIDAE

ca Pedipalps present 4. NYMPHONIDAE

FAMILY 1. PYCNOGONIDAE.

Body broad and flat ; mandibles and pedipalps wanting : 1 genus.

PYCNOGONUM Briinnieh. Ovigerous legs 10-jointed, wanting in the
female; accessory claws wanting: 10 species.

P. littorale (Strom) (Fig. 719). Length 16 mm.; spread of legs 38
mm.; eyes small, black, and widely separated, on a prominent tubercle;
ovigerous legs very small : Long Island Sound to Gulf of St. Lawrence,
from low-water mark to 400 fathoms, usually under stones; cosmo-
politan; Europe.

FAMILY 2. AMMOTHEIDAE.

Body broad and thick; mandibles not chelate; accessory claws
present or not: 9 genera and 30 species.

460

ARACHNIDA

TANYSTYLUM Miers. Mandibles 1-jointed and rudimentary; pedi-
palps 6-jointed; ovigerous legs 10-jointed and present in both sexes;
accessory claws present: 8 species.

Fig. 720

Tig. 719 — Pycnogonum littorale (Wilson). Explanations as in Fig. 721. Fig. 720 —
Tanystylum obiculare (Wilson). Explanations as in Fig. 721.

T. obiculare E. B. Wilson (Fig. 720). Length 1.5 mm.; spread of
legs 6.4 mm.; ovigerous legs about half as large in the female as in the
male : Vineyard Sound from low-water mark to 14 fathoms, on hydroids
or ascidians growing on wharves, etc.

FAMILY 3. PALLENIDAE.

Body rather stout; mandibles chelate; pedipalps wanting; accessory
claws wanting or not: 8 genera and 60 species.

1. PALLENE Johnston. Mandibles 3-jointed; legs very long; oviger-
ous legs 9-jointed ; accessory claws present : 10 species.

P. empusa E. B. Wilson. Length 1.5 mm.; spread of legs 13
mm. ; eyes red ; ovigerous legs about a third as long as the other legs in
the male, and smaller in the female : Long Island and Vineyard Sounds,
on hydroids in shallow water.

2. ANOPLODACTYLUS E. B. Wilson. Body slender; rostrum rounded;
mandibles 3-jointed; ovigerous legs 6-jointed and wanting in female;
accessory claws absent: 12 species.

A. lentus Wils. Length 7 mm.; spread of legs 30 mm.; eyes brown
or black; rostrum and mandibles long; ovigerous legs stout; legs very
long; color purple, sometimes gray or brown: common between tide marks
and in shallow water in Vineyard Sound, on hydroids and ascidians.

FAMILY 4. NYMPHONIDAE.

Body slender or broad, with a large tapering rostrum; mandibles
chelate; pedipalps present: 4 genera; 55 species.

PYCNOGONIDAE 461

NYMPHON Fabricius. Body slender, mandibles 3-jointed; pedipalps
5-jointed; ovigerous legs present in both sexes and 11-jointed; legs
slender, with accessory claws: 45 species.

N. stromi Kroyer (Fig. 721). Length 15 mm.; spread of legs 14
cm. ; ovigerous legs 19 mm. long, stout, slightly hairy : on muddy bottoms.

N. longitarse Kroyer. Length 7
mm.; spread of legs 65 mm.; entire
animal extremely slender, ovigerous
legs especially so: common from Cape
Cod to Nova Scotia, in from 16 to 115
fathoms.

N. grossipes (Fabricius). Length
10.5 mm.; spread of legs 9 cm.; color
light yellow, often with purple-banded
legs; eyes black, on a prominent tu-
bercle; ovigerous legs very slender:

very common from Long Island Sound ffig 2?

to Nova Scotia, in from 12 to 110 ["UTaidtmeS4 leg; 5> °v'gerous
fathoms.

CLASS 3. TRACHEATA.

Air-breathing arthropods with a distinct head and a single pair
of antennae, which respire through tracheae.

External Characters.— The more primitive tracheates are worm-like
animals in which the body is made up of a large number of similar
segments, without any division into thorax and abdomen; the head, how-
ever, is always distinctly set off. In the insects, the highest members of
the group, the body is divided into the three regions, head, thorax, and
abdomen. The paired appendages in the primitive tracheates occur along
the entire length of the body, a pair extending from each somite, except
usually the last one. In the insects, however, as in the Arachnoidea, the
abdomen is usually not provided with locomotory appendages. The head
appendages are a pair of antennae, which are preoral in position, a pair
of mandibles, which have no palps, and in most cases two pairs of maxillae.
A diagram showing the homologies of the appendages of tracheates and
the other arthropods is given on page 323.

The Tracheata are preeminently terrestrial and aerial animals and
breathe atmospheric air by means of tracheae, which open to the outside
through pores called spiracles. A very few insects live on the surface of
the sea and a considerable number of species are found in fresh water;
in the case of the latter, certain insect larvae breathe water, but most
aquatic tracheates still breathe the atmospheric air. The class contains
3 divisions.

462 ONYCHOPHORA

Key to the divisions of Tracheata:

di Body worm-like, with a large number of pairs of legs.

6X Body not externally segmented ; animals tropical and subtropical.

1. ONYCHOPHORA

Z>3 Body distinctly segmented 2. MYRIAPODA

oa Body divided into head, thorax, and abdomen ; 3 pairs of legs. . . .3. INSECTA

DIVISION 1. ONYCHOPHORA.* (PROTRACHEATA.)

Primitive, worm-like tracheates which combine annelid with tracheate
characters. The surface of the body does not show segmentation, but is
annulated, and from its ventral surface projects a series of pairs of short
annulated appendages, which in the various species may number from
14 to 43 pairs. The head bears a pair of simple eyes, a pair of segmented
antennae, a pair of hooked jaws surrounded by a circular lip, and a pair
of short leg-like oral papillae in which are the apertures of a pair of slime
glands; the sticky secretion of these glands serves to catch insects and
spiders. Coxal glands, of which there are as many pairs as legs, are also
present. On the under surface of each leg also is a conspicuous elongated
groove which is the opening of a nephridium. The skin is soft and
thickly beset with papillae.

The body cavity resembles that of insects in being an extensive blood
space and not a true ccelom. The digestive system consists of a straight
tube passing from the mouth to the anus at the hinder end of the body ;
the only digestive glands are a pair of long salivary glands. The heart
is a long muscular tube with segmental, paired openings. The respiratory
system consists of bunches of short tracheae, each of which opens through
a spiracle to the outside, and which are scattered irregularly above and
between the legs. The excretory system consists of a pair of nephridia at
the base of each pair of legs. Each nephridium opens into a vesicle
which is a remnant of the ccelom, and externally in the elongated groove
on the under surface of a leg. The nervous system consists of a dorsal
brain and of a pair of ventral chords which extend from the brain the
length of the body and unite behind the anus ; they are joined by numer-
ous transverse commissures. The sexes are separate, the genital opening
lying in front of the anus. The gonads are paired, their ducts being
modified nephridia. Some species are viviparous and some lay eggs. In
many forms the egg contains much yolk and segments superficially, as is
the case in insects, while in others it is poor in yolk and segmentation is
total, and the embryo is enclosed in folds of the uterus iand nourished by
means of a placenta.

* See "Monographic des Onychophores," by E. L. Bouvier, Ann. des Scl. Nat.,
Zool., 1907. "The Present Distribution of the Onychophora," etc., by A. H. Clark,
Smithsonian Misc. Coll., Vol. 65, 1915.

MTRIAPODA

463

The Onychophora live under bark and stones and in other damp,
dark places and feed on insects and other small animals.

History.— Peripatus was first described in 1825 and classified, because
of its slug-like appearance, with the mollusks. It was, however, soon after
placed among the worms and in 1851 was made one of the
subdivisions of annelids by Grube, to which he gave the
name Onychophora. Burmeister in 1856 placed the
group between the annelids and the arthropods, and
Moseley in 1874 finally demonstrated its relationship to
the latter group by showing the presence of tracheae.

The division contains 2 families with about 12
genera and 75 species, which are found in the Malay
Peninsula, the East Indies, Australia, New Zealand, Af-
rica, South and Central America, and the West Indies.

^~:'lz&~'~.

--ife

FAMILY PEBIPATIDAE.

Sexual orifice between the penultimate pair of
legs; 14 annulations to a somite on the back: tropical
America; East Indies; tropical Africa; about 5 genera
and 50 species.

Peripatus Guilding. Number of pairs of legs from
23 to 43, but is variable in the same species; legs with
4 to 7 spinous pads; feet with 3 to 7 distal papillae;
eggs minute; embryo with placenta: about 40 species.

P. (Oroperipatus Cockerell) eiseni* Wheeler (Fig.
722). Length 40 to 57 mm.; number of pairs of
legs 23 to 29 ; color reddish-brown : from Tepic, Mexico,
to Brazil.

DIVISION 2. MYRIAPODA.f

Tracheates with a distinct head and a trunk which is made up of a
large number of similar segments, each of which usually bears one or two
pairs of jointed appendages. The number of segments may vary from
eleven in Glomeris and Polyxenus to one hundred and seventy-three in
certain Geophilidae. The legs end each in a single claw, except in the
Symphyla, in which each leg has two claws. The appendages of the
head consist of a pair of segmented antennae, a pair of mandibles, and
one or two pairs of maxillae. The mandibles are without palps and

* See "A New Peripstus from Mexico," by W. M: Wheeler, Jour. Morph.,
Vol. 15, 1899.

t See "The Myriapoda of North America," by H. C. Wood, Jr., Trans. Am. Phil.
Soc., Vol. 13, p. 137, 1865. "The Classification of the Myriapoda," by J. S. Kingsley,
Am. Nat., Vol. 22, p. 1118, 1888. "The Myriapoda of North America," by C. H.
Bollman, Bull. No. 46, U. S. Nat. Mus., 1893. "Myriapoda," by C. Verhoeff, Bronn'sv
Klassen und Ord., etc., 5 Bd., 11 Abt, 1902-1907.

Fig. 722

Peripatus eiseni
(Wheeler).

464 MYRIAPODA

adapted for biting, except in the Polyzoniidae, in which the mouth parts
are suctorial. The Chilopoda, like the insects, have two pairs of maxillae;
the other Myriapoda have but one pair. In the Chilopoda, also, the first
pair of legs project forward beneath the head and are transformed into
hook-like claws or maxillipeds, each of which has a poison gland. Myria-
pods possess a pair of eyes, each consisting of a group of ocelli; in
Scutigera, however, compound eyes are present. The internal organs are
similar to those of insects. The sexes are separate, the single genital pore
in the Chilopoda being in the penultimate segment and the paired pores
of the Diplopoda in the second body segment. All Myriapoda lay eggs.
The young are born as larvae with three pairs of legs in the Pauropoda
and Diplopoda and six, seven, or more pairs in the Symphyla and Chilo-
poda; in certain of the latter group the larva possesses las many legs as
the adult, although they are not all well grown.

All Myriapoda are terrestrial animals which live in dark, damp places
and avoid the light. The Chilopoda live on animal and most of the
Diplopoda on vegetable food.

History. — Myriapods have been known from time immemorial and
usually much feared on account of the dangerous bite of certain of them.
Aristotle mentions both centipeds and millipeds, using the still familiar
names of Scolopendra and Julus. Both of these names were adopted by
Linna3us for his two genera of the 'animals, which he placed among the
Insecta aptera. The name Myriapoda was created by Latreille in 1796.
The animals were, however, retained among the insects until 1814, when
Leach formed a separate class of them equivalent to the Insecta. The
career of the group since that time has been a checkered one, having been
placed by some authors among the Crustacea and by others among the
Arachnida or the Insecta. Its right to be considered an independent
group may be said to have been definitely fixed by Newport (1844) and
Koch (1847). In later years attention has been called to the fact by
Kingsley,* Verhoeff, and others that the Myriapoda form two groups
instead of a single one, one of which, the Chilopoda (Latreille 1817), stands
in close relationship to the insects, "while the other, the Progoneata
(Pocock 1895), occupies an independent position.

The number of known species of Myriapoda is about 1,000, grouped
in two orders.

Key to the orders of Myriapoda:
at Genital pore near forward end ; body usually cylindrical, with mostly

2 pairs of legs to a segment 1. PROGONEATA

o, Genital pore near hinder end ; body flattened, with 1 pair of legs to a

segment 2. CHILOPODA

* See "The Classification of the Arthropoda," by J. S. Kingsley, Am. Nat., Vol. 28.
pp. 118 and 220, 1894.

SYMPHTLA 465

ORDER 1. PROGONEATA.

Body usually cylindrical; usually 2 pairs of legs to a segment; but
one pair of maxillae; with anteriorly placed genital pore; tracheae with-
out anastomoses and spiracles which cannot be closed: 3 suborders.

Key to the suborders of Progoneata:

av Animals minute ; but 1 pair of legs to a segment.

&! Antennae not branched 1. SYMPHYLA

&2 Antennae with 3 terminal branches 2. PAUEOPODA

a 2 Animals not minute ; 2 pairs of legs to most segments ; millipeds.

3. DlPLOPODA

SUBORDER 1. SYMPHYLA.*

Minute, colorless myriapods with a flattened body consisting of a
head and 14 segments, with 12 pairs of legs, each of which terminates
with 2 claws; projecting from the basal joint of each leg of the 10 hinder
pairs is a minute movable branch or parapod; antennae long; eyes absent
or minute; mouth parts consist of a pair of mandibles and a pair of
maxillae which form a sort cf underlip; a pair of long thick cerci project
from the hinder end of the body, each of which has a spinning gland; 2
spiracles present at the base of the antennae; the median, genital pore is
in the fourth segment ; young born with 6 or 7 pairs of legs : 1 family, 2
genera, and about 24 species, of which 4 are American, which are active
animals, found under stones, etc., in moist places.

FAMILY SCOLOPENDRELLIDAE.
"With the characters of the order : 2 genera.

1. SCUTIGERELLA Ryder. Posterior margin of all the dorsal plates
except the last either convex or emarginate, with 2 lobes; head sharply

Fig. 723

Scutigerella immaculata (Williams).
(Antennae abbreviated) 1, par-
apod ; 2, cercus.

separate from the trunk in the mid-dorsal area; first pair of legs well
developed and more than half as long as the following pair: 10 species,
2 in America.

* See "The Structure, Affinities and Species of Scolopendrella," by J. A. Ryder,
Proc. Acad. Nat. Sci., Phila., for 1881, p. 79. "Scolopendrella and Its Position in
Nature," by A. S. Packard. Jr., Am. Nat., Vol. IT., p. 698, 1881. "The Genera and
Species of the Order Symphyla," by H. J. Hansen, Quart, Jour, Mic. Soc., 1903,

466 MYEIAPODA

S. immaculata * (Newport) (Fig. 723). The last dorsal plate with
a very deep, median cavity; second plate deeply emarginate behind;
antenna with 19 to 50 joints; length up to 7.5 mm.: Massachusetts to
Texas, in old stumps, under moss, etc.; Europe.

S. nivea (Scopoli) (S. gratiae Ryder). No deep cavity in the last
dorsal plate, each segment with a pair of long setae projecting straight
out from body; second plate with the hinder margin straight or nearly
so ; length 2.5 mm. : eastern United States ; Europe.

2. SCOLOPENDRELLA Gervais. Posterior margin of all the dorsal
plates except the last in form of a pair of triangular plates; head not
sharply separate from the trunk; first pair of legs often rudimentary:
12 species, 2 American.

S. texana Hansen. Length 2.8 mm.; antennae with 19 to 22 joints;
cerci with a few long setae on the lower side, while all the other setae are
short; last pair of legs with 3 long dorsal setae on the penultimate
joint and 4 or 5 on the last joint : Austin, Texas.

S. pusilla Hansen. Length 1.7 mm.; antennae with 14 joints; last
pair of legs with 2 long dorsal setae on the penultimate joint and 3 on the
last joint : Austin, Texas.

SUBORDER 2. PAUROPODA.f

Minute myriapods in which the body consists of a head and 12
segments, the latter being covered in most cases by 6 large dorsal plates
and bearing 9 pairs of legs, each of which has a single terminal claw;
each antenna consists of 4 basal segments and 2 terminal branches,
one of which is larger than the other and ends with 2 flagella and either
a stalked or a sessile round knob; one pair of maxillae, which form an
underlip; eyes absent; 4 or 5 pairs of long tactile bristles project from
the sides of the body; heart and respiratory organs wanting; genital
pores just behind the second pair of legs, being paired in the male and
simple in the female; young born with only 3 pairs of legs: 2 families,
2 genera, and 6 species, 3 being American; they live in woody places,
under stones, etc.

FAMILY 1. PAUEOPODIDAE.

Body elongate and cylindrical, with long legs projecting laterally
beyond the trunk; color white; each dorsal plate with 2 transverse rows
of bristles: 1 genus.

* See "Habits and Structure of Scutigerella Immaculata (Newport)," by S. R.
Williams, Proc. Bost. Soc. Nat. Hist., Vol. 33, p. 461, 1907.

t See "A New Genus of Minute Pauropod Myriapods," by J. H. Ryder, Am. Nat,
Vol. 13, p. 603, 1879. "The Morphology and Classification of the Pauropoda," by
JT. C. Kenjon, Tufts College Studies, No. 4, p. 77, 1895..

DIPLOPODA

467

PAUROPTTS Lubbock. With the characters above given: 2 species,
1 American.

P. huxleyi Lub. (P. lubbocki Packard) (Fig.
724). Terminal knob of antenna sessile or nearly
so; length 1.3 mm.; width .35 mm.: Europe and
eastern and central United States.

FAMILY 2. EUEYPAUEOPODIDAE.

Segmentation indistinct; 9 pairs of legs pres-
ent; body very wide and flat,
and tuberculate and spinose
dorsally, with the head and the
short legs concealed under it;
color reddish ; antennal knob on
a long stalk: 1 genus and 3
species, 1 American.

EURYPAUROPUS Ryder.
With the characters above
given.

E. spinosus Ryder (Fig. 725)

Fig. 724 — Pauropus
huxleyi (Kenyon).

Fig. 725

Eupauropus spinosus
(Kenyon).

Length 1.25 mm. ;
width .5 mm.: eastern and central United States;
Europe.

SUBORDER 3. DIPLOPODA. (CHILOGNATHA.)

The millipeds (Fig. 726). Usually elongate and cylindrical myria-
pods with 2 pairs of legs on most of the segments; with the exception
of the first few and the last segments, each
has been formed by the fusion of 2 somites,
thus possessing 4 legs, 2 ganglia, 2 pairs of
spiracles, and 2 pairs of openings in the
heart ; antennae short, mostly 7-jointed ; but
one pair of maxillae present, which are
united to form an underlip called the gna-
fchochilarium ; an upper lip present in front
of the mouth; integument often hard, con-
taining calcium carbonate ; legs of each pair
spring from the ventral surface close to-
gether and near each leg is a spiracle ; a row
of the openings of stink glands usually pres-
ent along the side of the body, which secrete an offensive gas, which in
certain cases is hydrocyanic acid; tracheae of primitive structure, each
spiracle opening into a bunch of usually unbranched tubes; gonads usu-

Fig. 726 — Diagram of the
front end of a diplopod (Poly-
desmus) (Latzel). 1, female
genital pore ; 2, intestine ; 3,
dorsal plate.

468 MYRIAPODA

ally unpaired and in the hinder part of the body ; the paired ducts leading
to two openings in the second body segment ; one or both pairs of legs in
the seventh segment usually modified in structure in the male to serve as
copulatory organs; the young larvae with but 3 pairs of legs and few
segments: about 8 families and 125 American species, which are usually
sluggish animals living under stones and in other dark, moist places,
and feeding on decaying vegetable and animal matter, but also in some
cases on living roots and thus often proving destructive in gardens.
Key to the families of Diplopoda here described:

Oi Anus in terminal segment ; maxillae forming a plate ; integument hard ;
copulatory feet present.

&! Mouth parts suctorial and more or less like a proboscis 1. POLYZONIIDAE

&a Mouth parts not suctorial.
Cj Segments 30 or more in number.

dx Both pairs of legs on seventh segment of male copulatory.
Cj. Stink glands present ; anal segment rounded or produced into a spine.

2. JULIDAE

ea Stink glands absent ; anal segment usually elongated into 2 slender

papillae 3. CRASPEDOSOMIDAE

da Anterior pair of legs only on seventh segment of male copulatory.

4. LYSIOPETALIDAE

ca Segments 20 or 21; anterior pair of legs on seventh segment copu-
latory 5. POLYDESMIDAE

a, Anus on the penultimate segment ; maxillae leg-like ; integument soft,

with bunches of hairs; copulatory feet absent 6. POLYXENIDAE

FAMILY 1. POLYZONIIDAE.

Body elongate, with a hard integument, and wide and more or less
flattened, consisting of from 30 to 100 or more segments; mouth parts
more or less rudimentary and prolonged to form a suctorial proboscis;
row of stink glands on each side; both pairs of legs on the seventh
segment copulatory : 4 American genera with about 5 species, all of which
can roll themselves together so as to form a ball.

POLYZONIUM Brandt. First dorsal plate rounded in front and pro-
jecting to the base of the antennae, concealing nearly all of the ocelli,
which are 2 to 4 in number; antennae close together; legs very short,
the third segment being without them: 1 American species.

P. rosalbum (Cope). Color reddish-brown above, paler posteriorly
and along the margins; antennae very dark, with 6 joints; 39 to 53
segments: central states, often common.

FAMILY 2. JULIDAE.

Body elongate, cylindrical, and with a hard integument, consisting
of from 30 to 70 segments, the double pairs of legs beginning on the
fifth ; antennae on the sides of the head ; both pairs of legs on the seventh
segment of males copulatory; a row of stink glands on each side of the

DIPLOPODA 469

body; third segment usually legless: 7 American genera and about 50
species, all of which can roll themselves together.
Key to the genera of Julidae here described:

ox Third segment without legs.
&! Mandibular teeth 4.

cx Only the ventral plates of the first 2 segments free 1. JULUS

Cj All the ventral plates free 2. NEMASOMA

&3 Mandibular teeth 10 3. PARAJULUS

aa Third segment with legs.

&! All 4 anterior segments with legs . . .4. SPIBOBOLUS

&a Fourth segment without legs 5. CAMBALA

1. JULUS L. Eyes, if present, composed of a number of ocelli;
third segment without legs; first pair of legs of male 3-jointed, very
small; antennae delicate; copulatory legs of male usually hidden; only
the ventral plates of first segments free ; inandibular teeth

4: about 10 American species.

J. virgatus Wood (Fig. 727). Body yellowish-brown,
with a median and 2 lateral bands; eyes distant, composed
of 25 to 40 ocelli on a side; segments 30 to 35; legs 50 to
65 pairs; last segment rounded; length 12 mm.; width 1
mm. : common all over the country, especially in meadows ~£ in?w5od)*
and gardens.

J. venustus Wood. Color reddish-chestnut, lighter in young speci-
mens; segments 52 with usually two black dots on each side of each
segment ; last segment mucronate ; length 2 cm. : common in eastern and
central states.

2. NEMASOMA Koch. Similar to Julus, but all the ventral plates
free: 2 American species.

N. minutum (Brandt). Body brown, with a lateral row of ovate
black spots in each side, composed of 35 to 45 segments, 12 mm. long,
.8 mm. wide; feet pale, not extending beyond the body; eyes distinct,
with a dark band between them and with 8 or 9 ocelli on a side : common
in eastern and central states.

3. PARAJULUS Humbert and Saussure. Eyes composed of numerous
ocelli; third segment without legs, second pair very small; first pair
in males 6-jointed; mandibular teeth 10; number of segments 40 to
70, last segment more or less prolonged into a spine: 13 American
species.

P. impressus (Say). Body not hairy, chestnut brown, with a mid-
dorsal line and 2 lateral rows of black spots and composed of 45 to 55
segments, 32 mm. long and 2 mm. wide; 70 to 90 pairs of feet, sparsely
hairy; the first pair very large; ocelli 40 to 60 on a side; terminal spine
short: central and eastern states.

470 MTRIAPODA

P. pennsylvanicus (Brandt). Body rough and hairy, dark brown,
with a mid-dorsal line and 2 lateral rows of black spots, composed of
55 to 65 segments, 38 mm. long, 2 mm. wide; 100 to 112 pairs of pale
feet, densely hairy, first pair large; ocelli 40 to 70 on a side; ter-
minal spine small: common in the central and eastern
states.

P. canadensis (Newport) (Fig. 728). Body not
hairy, very dark brown, with 2 lateral rows of yellow
spots, composed of 56 segments, 25 mm. long, 1.5 mm.
wide; 86 to 93 pairs of very pale feet, sparsely hairy;
terminal spine large, round, and curved; ocelli 43 to 50:
northeastern states and Canada.

4. SPIROBOLUS Brandt. All anterior segments with legs; mandibu-
lar teeth 10; antennae short and thick: about 12 American species,
chiefly in the southern states and California.

5. marginatus (Say) (Fig. 729). Body dark brown
with a reddish ring on each segment, smaller specimens
greenish; feet and antennae reddish; composed of 53 to
57 segments ; 10 cm. or less long and 1 cm. wide ; 88 to 100
pairs of feet, extending beyond the sides of the body;
eyes indistinct, composed of 30 to 40 ocelli on a side;
antennae short, not reaching the hinder border of the first
segment: common in the eastern and central states.

5. CAMBALA Gray. Each eye composed of a single
row of 4 to 6 ocelli; fourth segment without legs; first
pair in males 6-jointed ; mandibular teeth 6 or 7 ; number
of segments 50 to 65 ; last segment rounded ; dorsal plates t,Fte- 729

o pit ro o o lit s

of segments with sharp, parallel ridges: 1 species. marginatus

C. annulata (Say). Body long and slender; color
yellowish-brown, with 2 lateral rows of dark brown spots; 70 to 112
pairs of legs ; length 38 mm. ; width 2 mm. : common in the eastern and
central states.

FAMILY 3. CRASPEDOSOMIDAE.

Like the Julidae, but without stink glands and with the terminal
segment elongated into 2 slender papillae: 6 American genera with
about 15 species.

CAMPODES Koch. Anterior pair of legs on eighth as well as both pairs
on seventh segment copulatory; body covered with fine hairs: 1 species.

C. flavicornis Koch. Body yellowish-brown, with a light mid-dorsal
line with darker spots, with about 30 segments, and 15 mm. long; eyes
triangular and prominent; antennae slender and long: often common
in the eastern and central states.

DIPLOPODA 471

FAMILY 4. LYSIOPETALIDAE.*

Like the Julidae, but with the first pair of legs only of the seventh
segment copulatory: 1 American genus.

LYSIOPETALUM Brandt. Body long and slender, tapering gradually
to the hinder end; seventh antennal joint conical and very short: 1
American species; several in Europe.

L. lactarium (Say) (Fig. 730). Body with about
60 segments and 115 pairs of legs, yellowish-brown
in color with mottled darker spots and bands; eyes
with 40 ocelli connected by a black band; length 35
mm.; width 2 mm.: common throughout the eastern
and central states.

FAMILY 5. POLYDESMIDAE.

(Fig. 726). Body more or less elongate, broad
and flattened, and with a hard integument, composed
of 19 or 20 segments and with 28 to 31 pairs of legs ;
the dorsal plate of each segment prolonged laterally
on each side to form a conspicuous wing; eyes absent; BW°h?nd
antennae long; a row of stink glands on each side, body,
usually with a swelling around each ; anterior pair of
legs only copulatory on seventh segment of male: 9 American genera
with about 50 species, all of which can roll themselves together.

Key to the genera of Polydesmidae here described:

«! Basal portion of leg without spines.
Z>! Anal segment pointed behind.
cx Dorsal plates flat.
di Each stink pore surrounded by a long, oval swelling ; each segment

with 2 or 3 transverse rows of tubercles 1. POLYDESMUS

da Each stink pore surrounded by a round swelling ; each segment with

4 or 5 rows of tubercles . . . , 2. SCYTONOTUS

c. Dorsal plates convex and smooth 3. LEPTODESMUS

62 Anal segment quadrate and smooth, or nearly so 4. EURYURUS

aa Basal portion of legs with spines 5. FONTARIA

1. POLYDESMUS Latreille. Male with 30, female with 31 pairs of
legs; each segment with 2 or 3 transverse rows of distinct tubercles; each
stink pore surrounded by an elongated swelling; lateral plates large and
horizontal in position: 9 American species.

P. serratus Say (P. canadensis Newport). Body brown, often red-
dish in color, about 37 mm. long; each dorsal plate with 2 rows of 4
rectangular tubercles in each; terminal spine of male copulatory ap-
pendage hook-shaped: common in the eastern and central states.

* See "A Revision of the Lysiopetalidae," by A. S. Packard, Proc. Am. Phil. Soc.,
Vol. 21, p. 177.

472

MYEIAPODA

Fig. 731
Polydesmus
moniliaris

(Wood).

P. moniliaris Koch (P. serratus Wood) (Fig. 731). Body deep
brown, about 20 mm. long; each dorsal plate with 3 rows of rectangular
tubercles; terminal spine of male copulatory leg double: eastern states.

2. SCYTONOTUS Koch. Each segment with 4 or 5 rows
of tubercles; each stink pore surrounded by a round
swelling: 3 American species.

S. granulatus (Say). Body brown, about 12 mm.
long; lateral plates not large: eastern and central states;
common.

3. LEPTODESMUS Saussure. Dorsal plates without
tubercles and more or less convex, the body being rather
narrow: 8 American species.

L. hispidipes (Wood). Color dark olive brown, some-
times with yellowish spots and a mid-dorsal black line;
legs roughened, with closely set, stiff hairs; genital ap-
pendages of male short and thick, with a curved, hairy
terminal spine: central states, being abundant towards
the south.

4. ETTRYTJRUS Koch. Dorsal plates smooth or with indistinct tuber-
cles; anal segment quadrate and not sharp behind: 2 American species.

E. erythropygus Brandt (Fig. 732). Body 28 mm. long and 3.5
mm. wide, olive chestnut in color, with a median and a pair of lateral
orange spots on each segment; terminal spine of

male copulatory appendage curved, and forked at
the end: common in the central states.

5. FONTARIA Gray. Basal portion of the legs
with spines; dorsal plates convex, with large lateral
plates: 20 American species.

F. virginiensis (Drury) (Fig. 733). Body chest-
nut in color with lateral plates of yellow; lateral
plates rounded in front, acute behind; terminal
spine of male copulatory appendage curved and
forked at the end and with a bristle springing from
it: common in the central states.

F. coriacea Koch. Body dark chestnut with a yellowish border on
each side; lateral plates very broad; terminal spine of male copulatory
appendage large and with a corkscrew twist: often common in the
central states.

FAMILY 6. POLYXENIDAE.

Body minute, short, broad, with a soft integument, and a bunch of
hairs on each side segment; the mandibles are entirely within the mouth

Fig. 732 Fig. 733

Fig. 732 — Euryurus
erythropygus

(Wood).

Fig. 733 — Fontwria

virginiensis

(Wood).

CHILOPODA

473

and the maxillae are leg-like; body with 11 segments with 13 pairs of
legs; eyes present; no stink glands; no copulatory feet in the male;
anus in penultimate segment: 1 genus.

POLYXENTJS Latreille. With characters given above: 1 species,
which cannot roll itself together.

P. f asciculatus Say. Length 2.5 mm. ; color pale brown ; head broad,
partly covered with hairs, with small eyes, and short thick antennae;
feet white: under stones and bark; the southern states; Long Island;
not common.

ORDER 2. CHILOPODA.*

The centipeds (Fig. 734). Elongate and flattened myriapods with
one pair of legs on a segment, Scutigera forming an apparent exception;
number of leg-bearing segments varies from
15 (Lithobius, Scutigera) to 173 (Geophili-
dae) ; antennae long and at least 12-jointed;
2 pairs of maxillae present, the first pair not
being united, the second being prominent
palp-like structures, the basal parts of which
are joined in the median line; a paired upper
lip in front of the mandibles; legs usually
long, those of each pair being widely sep-
arated from each other on the ventral sur-
face; the first pair modified to form a pair
of hook-like jaws called the maxillipeds,
which project forwards beneath the head and
are prehensile organs, each being provided

with a poison gland ; the broad bases of the maxillipeds are joined in the
middle line to form a lower lip; tracheae similar to those of insects,
consisting of branching and usually anastomosing trunks, the spiracles
being situated on the side of the body on certain of the segments; genital
glands open to the outside in the penultimate segment ; the young animals
possess all their legs at birth in the Geophilidae and Scolopendridae, and
7 pairs in the Lithobiidae and Scutigeridae: about 800 species, which are
active animals feeding on live animals and killing their prey with the
poison of the maxillipeds ; certain of the tropical Scolopendridae can inflict
a wound which is dangerous to man; 4 families.

* See "The Chilopoda of California," by R. V. Chamberlain, Pomona Jour. Ent.,
Vol. 4, 1912. "Notes on Geophiloidea from Iowa," etc., by same, Canad. Ent., Vol. 44,
1912. "The Geophiloidea of the Southeastern States," by same, Bull. Mus. Comp.
Zool., Vol. 54, 1912. "The North American Chilopods and Diplopods," by same, Ann.
Ent. Soc. Am., Vol. 5, 1912.

Ig. 734 — Diagram of the
front end of a chilopod (Mc-
Murrich). 1, first maxilla; 2,
second maxilla ; 3, maxilliped ;
4, first somite ; 5, first leg, on
second somite.

474 MTRIAPODA

Key to the families of Chilopoda:
aa Dorsal plates 15 or more.
&! Pairs of legs 21 or more.

<?! Pairs of legs 31 or more ; no eyes 1. GEOPHILIDAE

ca Pairs of legs 21 or 23 2. SCOLOPENDBIDAE

&a Pairs of legs 15 3. LITHOBIIDAE

a, Dorsal plates 8 ; 15 pairs of very long legs 4. SCUTIGERIDAE

FAMILY 1. GEOPHILIDAE.

Body very long and slender, with 31 to 173 segments, each composed
of 2 unequal subsegments, with an equal number of pairs of legs and
ventral plates; number of pairs of spiracles usually 2 less than the pairs
of legs ; antennae 14-jointed ; eyes absent ; young born with the full number
of legs ; habits relatively sluggish : about 5 American genera and 50 species.

1. GEOPHILTTS Leach. Number of segments 31 to 93; first pair of
maxillae with a pair of palp-like projections; dorsal plates with 2 longi-
tudinal grooves: about 20 American species.

G. rubens Say (G. cephalitis Wood). Body wide, especially the
head, about 45 mm. long, with 47 to 53 pairs of legs; color orange
anteriorly, dark olive over a greater part of the body, with a broad,
double, black median line; last ventral plate wide; anal legs hardly
longer than the others: common throughout the eastern and central
states.

G. umbraticus (McNeill). Pairs of legs 49, with long hairs, the
anal legs being slender and but little modified; color light orange in
front and behind and fuscous between ; body hairy above ; length 21 mm. :
central states, often very common.

2. LINOTJENIA Koch. Number of segments 39 to 70; head very
small; first pair of maxillae without palp-like projections and with the
exterior part 2-jointed ; anal legs 6-jointed ; claw of prehensile legs with
a basal tooth: 13 American species.

L. fulva (Sager). Body smooth, about 20 mm. long, tapering ante-
riorly, and with 47 pairs of legs, yellowish-orange in color; antennae
thread-like; basal joint of last pair of legs in male much thickened:
central states, often common.

L. ruber (Bollman). Body about 35 mm. long and 2 mm. wide,
with 67 to 73 pairs of legs ; color bright red in life, yellowish in alcohol ;
first pair of legs shorter than the second ; last pair not much longer than
the first and thickened: central states, often common.

FAMILY 2. SCOLOPENDEIDAE.

Body elongate, with either 21 or 23 segments and an equal number
of pairs of legs and ventral plates; number of spiracles 9, 10, or 11;
antennae with 17 to 31 joints ; eyes, when present, consist of 4 ocelli each ;

CHILOPODA

475

young born with the full number of legs: active animals found chiefly in
the warmer parts of the earth, where certain species attain great size and
are dangerous to man, although it seems doubtful if the bite of any of
them is fatal; 5 American genera and about 20 species. The largest
known centiped is Scolopendra gigantea L., which attains a length of 27
cm. or more, and is found in the East Indies.

Key to the genera of Scolopendridae here described:
aj Pairs of legs 21.

&! Eyes present 1. SCOLOPENDRA

62 Eyes absent.

<?! Anal legs not thick 2. CBYPTOPS

ca Anal legs very thick and short 3. THEATOPS

aa Pairs of legs 23 4. SCOLOPOCBYPTOPS

1. SCOLOPENDRA L. Number of pairs of
legs 21 ; 9 pairs of slit-like spiracles ; 4 ocelli on
each side ; dorsal plate of head heart-shaped and
extending back over the first segmental plate:
over 50 species, about 10 American, which are
found principally in the south.

S. morsitans L. Body 65 mm. and more
long and greenish in color; antennae green;
lateral edges dark green; legs short, not longer
than the 3 terminal body segments: cosmopoli-
tan; rather southerly in America.

S. heros Girard (S. castaniceps Wood) (Pig.
735). Body 10 cm. long or more, yellow and
green in color ; antennae 25-jointed ; penultimate
joints of legs armed with spines; first dorsal
plate with a transverse suture; anal legs long,
with 17 to 25 spines: Mexico and the southern
states, extending north to Kentucky.

2. CRYPTOPS Leach. Number of pairs of
legs 21; 9 pairs of slit-like spiracles; antennae
17-jointed ; eyes absent ; anal legs not thickened :
over 20 species, 1 or 2 being American.

C. hyalina Say. Body about 15 mm. long,
smooth and very flat, with reddish-brown head
and 2 black internal longitudinal lines: eastern
and central states, north to New Jersey and
Indiana, often common.

3. THEATOPS Newport. Similar to Cryptops but with the anal legs
very thick and short and with the last dorsal plate twice as large as the
preceding: 2 American species.

Fig. 735 — Scolopen-
dra heros (Wood).

476

MTEIAPODA

T. postica (Say) (Fig. 736). Body about 45 mm. long, reddish in
color; anal legs close together and parallel, with the tips crossing, their
basal position without spines: eastern and central states, north to
Virginia and Illinois, often very common.

4. SCOLOPOCRYPTOPS Newport. Number of legs 23;
10 or 11 pairs of spiracles; eyes absent; cephalic dorsal
plate extends back over the first segment, which has no
transverse suture; antennae 17-jointed: 4 American
species.

5. sexspinosa (Say). Body 65 mm. long, reddish in
color; feet yellow; antennae yellow and hairy; basal por-
tion of anal legs with 2 large spines (inner one sometimes
atrophied in northern specimens) ; cephalic plate mar-
ginate; anterior margin of the lower lip (basal portion
of maxillipeds) nearly straight, not toothed: entire United
States, often very common.

Fig. 736
Theatops pos-
tica (Wood).

/

FAMILY 3. LITHOBIIDAE.

Body with 15 leg-bearing segments, of which 9 are large and 6
(segments 2, 4, 6, 9, 11, and 13) small, the anterior segment bearing the
maxillipeds and the anal segment being without appendages; with 15
pairs of legs, in the coxae of the last 4 pairs of
which are the openings of coxal glands; eyes com-
posed of usually many ocelli; maxillary palp
3-jointed; young born with 7 pairs of legs: 10
genera, with about 250 species, about 50 species
being American.

LITHOBIUS Leach. Spiracles on segments 3, 5,
8, 10, 12, 14, and sometimes also 1; coxa of maxilli-
peds with 2 to 8 teeth on each side; antennae with
usually 20 to 50 joints: over 200 species, about 47
American.

L. forficatus (L.) (Fig. 737). Body about 28
mm. long, anal legs 10 mm. long; color brownish or
yellowish; antennae half as long as the body, with
33 to 43 joints; ocelli 23 to 48 in number; posterior angles of dorsal
plates 9, 11, 13 elongated: the entire country; Europe; South America;
often very common.

L. multidentatus Newport (Fig. 738). Body about 25 mm.; anal
legs 10 mm. long; color brown; antennae short, with 19 to 23 joints;
ocelli 27 to 35 in number; posterior angles of dorsal plates 6, 7, 9, 11, 13
elongated: eastern and central states; common.

»,

/

I £

1 1

x *li

\ 1

/

^1

1

s K

7

f 1

i!

Fi

g. 737 Fig

738

Fig. 737 — LitfioMus

forficatusC\\ood;.
Fig. 738 — LithoWus

multidentatus

(Wood).

CH1LOPODA

477

FAMILY 4. SCUTIGERIDAE.

Body relatively short, consisting of about 15 segments, the dorsal
surface of which is covered by 8 large plates; 15 ven-
tral plates and 15 pairs of very long legs, the last pair
being longer than the body and used as anal feelers;
antennae and maxillary palps very long; eyes large
and composite; spiracles a row of 7 mid-dorsal slits;
young born with 7 pairs of legs: 13 genera and 30
species, 2 being American, which are found in damp
places in houses, especially in cellars, where they feed
on cockroaches and other insects.

SCUTIGERA Lamarck. With the characters above

given.

S. forceps (Rafinesque) (Fig. 739). Body about
25 mm. long, light brown in color, with 3 longitudinal
dark stripes; last pair of legs 50 mm. long: western
and central states, very common towards the south; in New England
as far north as Boston.

Fig. 739— Scuti-

gera forceps

(Wood).

PHYLUM 6.

MOLLUSCA.*

Bilaterally symmetrical, unsegmented animals in which the body is
usually encased in a calcareous shell, and is made up of four parts, the

visceral mass, the head, the mantle,
and the foot (Fig. 740).

External Structure.— The vis-
ceral mass (1), which forms the
greater part of the body, contains
the viscera, closely compacted to-
gether. At its anterior end is the head
(13), with the mouth and the most
important organs of special sense, and
from its dorsal side the mantle falls
as an extensive integumental fold
over its sides and more or less com-
pletely envelopes it (2), while from
its ventral side extends the foot
(11), a muscular mass by means of
which the animal moves.

In the pelecypods and scapho-
pods the head is wanting, the mouth
being at the forward end of the
visceral mass. In the same ani-
mals also the mantle is a double
fold, one half falling to the right
and the other to the left of the

molluscan structure .

A, the

cephalopod type ; B, the gastropod type ;

C, pelecypod type. 1, visceral mass ; 2,
shell and mantle ; 3, mantle cavity ;
4, anus ; 5, siphon ; 6, visceral gan-
glion ; 7, pedal ganglion ; 8, arms on
head ; 9, mouth ; 10. cerebral ganglion ;
11, foot; 12, tentacles; 13, head.

* See "Manual of Conchology," by G. W. Tryon and H. A. Pilsbry, Philadelphia,
1878 to date. "Manual de Conchologie," etc., by P. Fischer, Paris, 1880-1887.
"Structural and Systematic Conchology," by G. W. Tryon, Jr., 1882. "Mollusca,"
by J. S. Kingsley, Stand. Nat. Hist., Vol. 1, 1888. "A Preliminary Catalogue of the
Shell-bearing Mollusks," etc., by W. H. Dall, Bull. No. 37, U. S. Nat. Mus., 1889.
"Mollusca," by H. Simroth, Bronn's Kl. u. Ord., Vol. 3, 1892 to date. "Mollusks,"
by A. H. Cooke, Camb. Nat. Hist., Vol. 3, 1895. "Molluskan Fauna of Philadelphia,"
by M. Schick, Nautilus, Vol. 8, p. 133, 1895. "Molluscan Fauna of Western New
York," by F. C. Baker, Trans. Acad. Sci., St. Louis, Vol. 8, p. 71, 1898. "West Amer-
ican Shells," by J. Keep, San Francisco, 1904. "Mollusca," by Paul Pelseneer in "A
Treatise on Zoology," edited by E. R. Lankester, 1906. "The Shell-book," by Julia E.
Rogers, 1909. "A Biological Survey of Woods Hole and Vicinity," by F. B. Sumner
and others, Bull. Bur. Fish., Vol. 31, 1911.

478

DESCRIPTION

479

visceral mass ; in other mollusks, on the other hand, the mantle is a
single fold covering the visceral mass on all sides as a thimble covers
the finger.

The outer surface of the mantle secretes the shell, which may be
regarded as the cuticula and is usually charged with calcium carbonate,
while the space between the mantle and the visceral mass is called the
mantle cayity (3). This space is important in that it contains the
gills, and that the digestive, excretory, and reproductive organs usually
empty their products into it. A mantle is wanting in many mollusks,
which are also without a shell. Other mollusks which have a mantle
may lack the shell; in many slugs and also in the squids the shell is
buried in a pocket of the mantle and is not on the surface. The shell
thus takes the form of the mantle, and may be bivalved or univalved,

Fig. 741

Fig. 742

Fig. 741 — Diagrammatic cross sections of gastropods. A, a prosobranch with
epipodia ; B, an opisthobranch with parapodia (.Liang). 1, shell; 2, visceral mass;
3, foot ; 4, gill ; 5, epipodium ; 6, parapodium. Fig. 742 — The mouth and pharynx
with the radula of a snail (Lang). 1, pharynx; 2, radula ; 3, jaw; 4, mouth;
5, tongue ; 6, opening of salivary glands ; 7, oasophagus.

and spiral or cone-shaped. The shell is usually composed of three
layers, the inner mother-of-pearl layer which is secreted by the general
surface of the mantle, and the middle columnar and outer periostracal
layers which are secreted by its lower margin.

The foot is flat and used for creeping by the chitons, gastropods,
and a few pelecypods, this probably being its primitive form and use.
It may have a variety of forms in other mollusks and the following
divisions may in certain cases be distinguished in it: the propodium or
forward and the metapodium or hinder portion, the parapodia or lobe-
like extensions of the sole (Fig. 741,6), and the epipodium, a ridge
along the side (Fig. 741,5).

Internal Structu re.— Correlated with the compactness of the visceral
mass is the small extent of the coelom, which is usually confined to the
pericardial space and the cavities of the gonads. The mouth opens
into a muscular pharynx (Fig. 742) in all mollusks except pelecypods,

480 MOLLUSCA

which contains a rasping organ called the radula: an oesophagus, a
stomach with a large liver, and an intestine form the remainder of the
alimentary canal. The radula (Fig. 742,2) is a chitinous ribbon set
with minute calcareous teeth in regular longitudinal and transverse
rows which works over a muscular tongue. The teeth vary in number
from one in Ch<e.toderma to thousands in many snails and are often of
great importance in classification, inasmuch as in each species they
have usually a characteristic arrangement and shape. In each trans-
verse row there is typically a single central tooth, on each side of
which are one or more laterals, and at the side of these, one or more
marginals (Fig. 830). The respiratory system consists typically of a
pair of ctenidia, or comb-shaped gills in the mantle cavity (Fig. 821, A).
They are modified in various ways among the different mollusks and in
pulmonate snails, nudibranchs, and some others, are wanting, respira-
tion being performed by lungs or by other organs. The circulatory
system consists of a heart, arteries which distribute the blood to lacunar
spaces in the tissues, and veins which take it from these spaces to the
kidneys and respiratory organs and thence to the heart. The heart con-
sists typically of a muscular ventricle (Fig. 821,3), which drives the
blood through the arteries (4), and one or two pair of auricles (2), which
receive it from the gills. Snails with but one gill or lung have also but
one auricle. The heart thus always contains arterial blood. The ex-
cretory system consists typically of paired sac-like kidneys (nephridia)
which open into the mantle cavity at their hinder ends (Fig. 746, 14)
and into the pericardial space (the coelom) at the forward. The nervous
system contains four principal pairs of ganglia with nerves joining
them. These are the cerebral ganglia (Fig. 740, 10), just above the
oesophagus, which form the brain, the pedal (7), the visceral (6), and
the pleural ganglia. The cerebral ganglia are joined with the pedal and
visceral ganglia by nerve connectives; in gastropods the pleural ganglia
lie in the course of the cerebro-visceral connectives; in pelecypods they
are joined with the cerebral and in cephalopods with the visceral
ganglia.

The most important special sense organs consist of camera-obscura
eyes and tentacles usually on the head, but in the pelecypods in the edge
of the mantle when present, lithocysts in the foot, and osphradia, organs
of taste or smell, near the base of the gills.

The gonad is single in all mollusks except the pelecypods and
Solenogastres, in which it is paired; the ducts leading from the gonad
open usually into the mantle cavity, and are either paired or single.
The sexes are usually separate, although numerous hermaphrodites
(pulmonates, opisthobranchs) occur. The young animal in most

DESCRIPTION 481

cases goes through a metamorphosis after birth, the characteristic
molluscan larva being called the veliger larva. A few mollusks are
viviparous.

Distribution and Habits. — The majority of mollusks are aquatic
animals, most of them living in the sea. Many species live in fresh
water and many have become terrestrial animals, although the latter
usually require a moist environment. The pelecypods, which have no
radula, feed on minute organisms suspended in the water. The majority
of the mollusks with a radula feed on vegetal substances; all the cepha-
lopods, however, and very many gastropods are predacious animals and
a few of the latter are parasitic. The cephalopods are active and power-
ful beasts of prey and include among their number the largest and most
highly developed invertebrate animals.

Hist ory.— Although mollusks have been well known from the earliest
times on account of their conspicuous shells, it was not until the time of
Cuvier that the foundation of the modern classification was laid. Guided
by his own extensive anatomical studies and those of Poli and other con-
temporaries, Cuvier, in 1795, subdivided the class into the three orders of
Cephalopoda, Gasteropoda, and Acephala, which is the foundation of their
modern arrangement. Linnseus had made the mollusks one of his four
subdivisions of Vermes, including among them only the slugs, squids, octo-
pods, and other soft, shell-less animals. The shell-bearing mollusks he
included in the class Testacea, which he subdivided into Bivalvia, Univalvia,
and Multivalvia.

The first students of mollusks in America, as elsewhere, were the col-
lectors of shells. The first scientific descriptions of importance were pub-
lished by Thomas Say in 1817, who between that date and 1834, when he
died, described a large number of species. C. S. Rafinesque, during almost
the same period, also described large numbers of species, especially of
fresh-water and land mollusks. It was by these two men and certain of their
contemporaries and immediate followers, notably T. A. Conrad and Isaac
Lea, that the foundations of the present knowledge of American mollusks
were laid. Of the many students of mollusks of the middle of the century
Gould, Stimpson, arid A. and W. G. Binney are especially to be mentioned.
Of late years especially noteworthy is the publication by the Academy
of Natural Sciences in Philadelphia of the Manual of Conchology, a
monographic work in many volumes which will cover the entire field. It
was begun in 1878 by G. W. Tryon and is being continued by H. A.
Pilsbry.

The phylum Mollusca contains over 60,000 living species and a very
large number of fossil ones, it being the largest phylum of animals except
the Arthropoda: they are grouped in 5 classes.

482 MOLLUSCA

Key to the classes of Mollusca:

a^ No distinct head present.
&! Shell when present not bivalve.

cx Body either naked or with shell consisting of 8 plates 1. AMPHINEUKA

ca Cylindrical shell present 2. SCAPHOPODA

62 Bivalve shell present 4. PELECYPODA

oa Distinct head present.

&! Head with 1 or 2 pairs of tentacles; shell coiled or conic. .3. GASTROPODA
b, Head with long arms 5. CEPHALOPODA

CLASS 1. AMPHINEURA*

Bilaterally symmetrical mollusks, worm-like in appearance and with
usually an inconspicuous head. The mouth is at the forward and the anus
at the hinder end of the body, and on either side are the gills and the
nephridial pores. The mantle is not extensively developed but consists
of a slight fold extending from the sides and the hinder end of the body,
enclosing a narrow mantle cavity (Fig. 746, 5). The integument of the
back is thick and contains calcareous spicules or is covered with scale-
like plates. A radula is usually present. The nervous system (Fig. 745)
is very primitive in form, consisting of an 03sophageal ring and four
longitudinal nerves, two pedal, which innervate the foot, and two pallial,
which pass along the mantle furrow; these may or may not contain
definite ganglia.

History.— The class Amphineura was formed in 1877 by von Ihering,
who maintained, as Huxley and Leuckart had already done, that Chiton
was related to ClfKEtoderma, which, until then, had been placed among the
Gephyrea, and to Neomenia, whose position in the system had been very
uncertain, but he placed the new class among the worms. Chiton was first
studied by Cuvier, although it had been long known, who placed it beside
Patella among the Prosobranchiata, where it remained almost down to the
present day. Gegenbaur in 1878 erected the group Solenogastres, which he
placed among the worms. In 1881 Spengel brought the Amphineura of
von Ihering among the Mollusca, where they have since remained as their
most primitive representatives. The modern arrangement of the group
is due largely to Pilsbry and Simroth.

The Amphineura are all marine, living in most cases on the bottom,
near the shore, or in moderate depths. The class contains two orders,
with about 630 species.

Key to the orders of Amphineura:

Oj No shell present 1. APLACOPHOBA

a. Shell present 2. POLYPLACOPHORA

* "Amphineura," by H. Simroth, Bronn's Klass. u. Ord., Vol. 3, 1892,

AMPHINEURA 483

ORDER 1. APLAOOPHORA.* (SOLENOGASTRES.)

Body worm-like, being more or less cylindrical and usually elongate,
and without a shell. The exceptionally thick cuticula contains calcareous
spicules which sometimes project above the surface and represent the shell
of the higher mollusks. On the ventral surface, except in Chatoderma, is
a median longitudinal groove representing a rudimentary mantle cavity,
the two sides of which are formed by the mantle-folds. Within this groove
lies a ciliated ridge which represents the rudimentary foot. At the hinder
end of the body this groove widens to form the cloacal cavity, in which are
the anus, the two kidney pores, and the two gills.

The mouth opens into a pharynx in which a radula and salivary glands
are usually present. The alimentary tract is straight. The nervous system
is more highly developed than in Chiton, and has a distinct brain and
numerous ganglia. The heart lies in a large pericardium at the hinder end
of the body; this cavity represents the co3lom and communicates with the
cloacal cavity by means of a pair of nephridial tubes. The gonads iare
paired and, except in Ch&toderma, hermaphroditic. They are sac-like in
structure and lie in front of the pericardium, into which they open. Their
products pass into the pericardium and through the nephridia to the outside.

The Solenogastres are marine animals which live on or near the bottom
in from 20 to 1,000 fathoms, in various parts of the world. Many species
live on and among hydroids; others feed on crustaceans and many on
plants.

The order contains 2 suborders, 13 genera, and about 30 species.

Key to the suborders of Aplacophora :

o, Mid-ventral groove present 1. NEOMENIINA

a. No mid-ventral groove 2. CH^ETODEBMATINA

SUBORDER 1. NEOMENIINA.

Head and cloaca but little or not at all developed; mid- ventral
groove present, at the forward end of which is a large gland ; gills simple,
sac-like evaginations of the cloaca and not feathered; animals hermaph-
roditic ; nephridia unite and open to the outside through a single median
pore beneath the anus; radula sometimes wanting; intestine with lateral
pockets : 4 families and about 27 species.

FAMILY 1. NEOMENIIDAB.

Body short and thick, with both ends alike; cloaca and mouth ven-
tral, the former with a row of short respiratory papillae around its edge ;

* Sec "Aplacophora," by H. A. Pilsbry, Man. of Conch., Vol. 17, 1892.

484 MOLLUSCA

body covered with spieules, also with papillae; no radula present, the
pharynx being protrusile: 1 genus; North Atlantic, Mediterranean Sea,
and West Indies.

NEOMENIA Tullberg. With the characters of the family: about
4 species.

N. carinata Tull. (Fig. 743). Body 2 to 3 cm. long
and half as thick ; back with a keel : North Atlantic.

Fig. 743— Neo- FAMILY 2. PEONEOMENIIDAE.

menia carinata
(Cambridge Nat- Body elongate, 9 to 14 times as long as thick ; radula

ui'til History).

present; body covered with spieules: 4 genera.
PRONEOMENIA Hubrecht. With the characters of the family: 2
species.

P. sluiteri Hub. Length 10 to 14 cm. : Arctic seas.

SUBORDER 2. CH^ETODERMATINA.

Mouth and cloaca terminal; head end and hinder end set off by con-
strictions; body cylindrical, without ventral groove, and covered with
spieules; 2 feathered gills present; sexes separate: in the North Atlantic
and the Pacific Oceans, burrowing in the mud; 2 genera.

CiLffiTODERMA Loven. With the characters of the suborder: 3
species.

C. nitidulum Lov. (Fig. 744). Length 25 mm.; width 2 mm.: coast
of Scandinavia and northern America; Gulf of Maine; in 100 fathoms.

ORDER 2. POLYPLACOPHORA.* (CHITONS.)

Body from 10 mm. to 15 cm. in length, elliptical in shape, convex
dorsally and flattened ventrally, and bearing on its dorsal surface a lon-
gitudinal row of eight calcareous plates or valves (Fig. 745). These
plates possess characteristic form and markings and usually overlap pos-
teriorly. They are composed of two distinct layers, the lower layer,
the anterior portion of which extends forwards beneath the overlapping
valve in front of it and is called the articulamentum, and the exposed
layer, which is the tegmentum. They are surrounded and kept in place
by a muscular integumental fold called the girdle, the portions concealed
by the girdle being called the insertion plates. In Cryptochiton the
girdle entirely covers the shell, and in several other genera it almost covers

* See "On Certain Limpets and Chitons from the Deep Waters of the Eastern
Coast of the United States," by W. H. Dall, Proc. U. S. Nat. Mus., Vol. 4, p. 400.
"Polyplacophora," by H. A. Pilsbry, Man. of Conch., Vol. 14 and 15, 1892. "Chitons
Collected by Dr. Harold Heath," etc., by H. A. Pilsbry, Proc. Acad. Nat. Sci.,
1898, p. 287.

AMPHINEURA

485

it. The girdle varies much in character, its upper surface being either
horny, covered with scales, or densely beset with spines. The foot is
usually broad and flat, and is both a creeping surface and a sucker to
attach the animal to the rocks; in a few forms the foot is much reduced

Fig. 745

Fig. 744 — Chcetoderma nitidulum (Cambridge Natural History). 1, mouth; 2,
anus. Fig. 745 — Chiton squamosus. A, dorsal aspect ; B, diagram showing mouth
(1), brain (2), pleurovisceral nerve chord (3), pedal nerve chord (4), gills (5), and
anus (6).

and narrow, especially in certain vermiform species. The mantle (Fig.
746) is a fold which projects over the side of the foot enclosing a deep fur-
row along each side and at the hinder end of the body, which is the mantle
cavity (5). In this cavity at the sides of the body are from 6 to 80 pairs
of gills (6) and the genital and kidney
pores, which are also paired. The mouth
is at the forward and the anus at the
hinder end. The head is rudimentary
and tentacles are absent. Special sense
organs are poorly developed, the most
important being peculiar sense buds
called aesthetes, which are present in
definite groups in the shell; in certain
species these organs are modified to
form eyes. Fig 746— Diagram of a cross sec-

The mouth opens into the pharynx, "Tdiul f £*$S«££?k airE^
in which a radula is present; a pair of |; b£™ Jg{| iTJBiaSBJ
salivary glands join the pharynx. The SSSffffi ISSSrSfS^Sl
digestive tract is made up of a short g^ »»H*» ;. # pedal nerve
oesophagus, a stomach with a pair of

livers, and a long coiled intestine. The nervous system (Fig. 745) is char-
acterized by the lack of definite ganglia, except two small pairs near the
pharynx, most of the ganglion cells being distributed throughout the larger
nerves. The heart consists of a tubular ventricle (Fig. 746, 2) and a pair
of auricles (3), and lies in a pericardium (1), which represents the hinder

486 MOLLUSCA

part of the coeloin and communicates with the mantle cavity by means of
the extensive nephridia (13, 14). The sexes are separate, the gonad com-
municating with the mantle cavity by a pair of ducts which join it in
front of the nephridial pores. The eggs are sometimes laid in a common
jelly which is attached to the rocks, or they may be attached separately
or in small groups. Chiton polii retains its eggs in the mantle cavity until
they hatch. The young are bom as trochophore larvae.*

The Polyplacophora are found in all parts of the world, occurring
chiefly in shallow water, although a few species live in the deep sea.
They attach themselves to rocks, shells, corals, etc., feeding on diatoms
and other plants. In the West Indies and other places they are an
article of food, the foot being called sea beef. About 600 species are
known, grouped in 3 suborders.

Key to the suborders of Polyplacophora:

tti Valves without insertion plates 1. EOPLACOPHORA

fl.2 All valves with insertion plates.

&! Margin of insertion plates not pectinate 2. MESOPLACOPHORA

6, Margin of insertion plates pectinate 3. TELEOPLACOPHORA

SUBORDER 1. EOPLACOPHORA.

Valves of large size, the anterior and posterior ones similarly articu-
lated; insertion plates absent, except in certain cases on the anterior
valve, and unslit: 1 family.

FAMILY LEPIDOPLEUEIDAE.

With the characters of the suborder: 4 genera.
HANLEYIA Gray. Insertion plates wanting on all valves
of the shell but the anterior one, and here they are unslit,
but roughened; girdle with spines: 3 species.

H. mendicaria (Mighels and Adams) (Fig. 747). Shell
grayish with a red margin, elliptical ; surface with elevated
dots, without concentric striae; gills posterior, about 15 on
a side; length 27 mm.; breadth 15 mm.: northern New England, in
shallow water.

SUBORDER 2. MESOPLACOPHORA.

All the valves with insertion plates, either the first alone or the first
7 of which are slit, and with smooth or roughened but not pectinate
margins ; eyes absent : 4 families.

* See "Contributions to the Embryology of Chiton," by M. M. Metcalf, Johns Hop.
Univ., Stud, from Biol. Lab., Vol. 5, p. 249, 1893.

AMPHINEUEA 487

Key to the families of Mcsoplacopliora here described :

«! Tegmenta of the valves fully exposed.

&! Last valve without a posterior sinus 1. ISCHNOCHITONIDAE

&a Last valve with a posterior sinus 2. MOPALIIDAE

% Tegmenta more or less reduced or covered by the girdle.

3. ACANTHOCHITONIDAE

FAMILY 1. ISCHNOCHITONIDAE.

Valves of large size and exposed, the anterior and posterior ones
similarly articulated; insertion plates smooth or nearly so and slit into
teeth which project outwards: 12 genera, containing some of the common-
est species along our shores.

Key to the genera of Ischnochitonidae here described:

«! No radiating ribs on the anterior valve.

6i Girdle smooth, without scales or hairs 2. TONICELLA

&a Girdle not smooth.

Ci Girdle hairy 1. CPLETOPLEUBA

ca Girdle granulated 3. TRACHYDERMON

c3 Girdle covered with scales 4. ISCHNOCHITON

aa Anterior valve with radiating ribs 5. NUTTALLINA

Fig. 748 Fig. 749 Fig. 750

Fig. 748 — Chcetopleura apiculata (Gould). Fig. 749 — Tonicella nlarmorea (Gould).
Fig. 750 — Trachydermon ruber (Gould).

1. CHJETOPLETTRA Shuttleworth. Umbo of posterior valve central
or anterior; girdle leathery and more or less hairy: 16 species.

0. apiculata (Say) (Fig. 748). Shell oval, light buff or ashen, some-
times reddish in southern specimens, keeled, central areas with longitu-
dinal rows and lateral areas and end valves with irregularly scattered
tubercles; gills, 24 on a side, extending almost to anterior end; length
17 mm. ; breadth 10 mm. : Cape Cod to Florida, very common in shallow
water.

2. TONICELLA Carpenter. Umbo of posterior valve anterior; girdle
leathery and smooth, without scales or hairs: 7 species.

T. marmorea (Fabricius) (Fig. 749). Shell oval, buff-colored, closely
speckled with dark red; surface densely, microscopically granulated;
gills 20 to 25 on a side, extending three-quarters the length of the foot;
length up to 40 mm. ; breadth 24 mm. : circumpolar, south to Massachu-
setts Bay and to Aleutian Islands; Europe.

488 MOLLUSC A

T. lineata (Wood). Shell rather low, light reddish in color; surface
not granulated and shining; gills as in T. marmorea; length 37 mm.;
breadth 20 mm.: Pacific coast from Monterey to Bering Strait.

3. TRACHYDERMON Carpenter. Girdle covered with minute granules
or scales: several species.

T. albus (L.). Shell elevated, minutely granulated, keeled; anterior
valve semicircular; color whitish, sometimes shading into a light orange
on each valve; interior white; length 15 mm.; breadth 7 mm.: circum-
polar, south to Cape Cod; Pacific coast; Europe; low-water mark to 337
fathoms, often abundant.

T. mber (L.) (Fig. 750). Shell smooth, elevated, microscopically retic-
ulated, buff in color, marbled with reddish ; 12 mm. long and 7.5 mm. wide ;
interior bright pink : circumpolar, south to Long Island Sound and Sitka ;
Europe ; from low water mark to 80 fathoms ; rare south of Cape Cod.

4. ISCHNOCHITON Gray. Girdle covered with imbricating scales:
numerous species.

I. magdalenensis (Hinds). Shell elongate and rather narrow, faintly
mottled with olive on a light ground; central areas pitted; lateral areas
and end valves with radiating lines ; length 75 mm. ; breadth
30 mm.: Monterey, California, to Magdalena Bay.

5. NTJTTALLINA Carpenter. Valves exposed, granulated,
the lateral areas having 2, the head valve numerous low
radiating ribs; girdle varying from spiny to scaly; umbo
behind the middle: several species.

N' californica (Nuttall) (Fig. 751). Shell more than
Ca/Keep)Ca twice as long as wide, dark brown in color, with whitish
streaks; median valves strongly beaked with a smooth
rounded dorsal ridge ; girdle covered with minute spines ; length 37 mm. ;
breadth 15 mm.: coast of Oregon, Washington, and California.

FAMILY 2. MOPALIIDAE.

Valves of large size on a broad body; each intermediate valve with
a single slit; posterior valve with a median sinus; insertion plates on all
the valves; girdle hairy, never scaly; gills extend the length of the foot:
3 genera; Pacific Ocean.

MOPALIA Gray. Valves exposed; insertion plate of anterior valve
slit into nearly smooth teeth; insertion plate of posterior valve with an
oblique slit on each side: 5 species, all on Pacific coast.

M. muscosa (Gould). Shell oval, brownish in color, but sometimes
bright green or red, anterior valve having about 10 radiating ribs ; length
50 mm. ; breadth 3.8 mm. : coast of Washington, Oregon, and California,
between tide lines.

AMPHINEURA 489

FAMILY 3. ACANTHOCHITIDAE.

Shell reduced and more or less covered by the smooth or hairy (never
scaly) girdle: 6 genera.

Key to the genera of Acanthochitidae here described:

at Shell not completely covered.

&x Tegmenta bottle-shaped; last valve with a median sinus.... 1. KATHABINA
62 Tegmenta heart-shaped ; last valve rounded 2. AMICULA

oa Shell completely covered 3. CBYPTOCHITON

1. KATHARINA Gray. Valves two-thirds covered by the girdle, the
exposed portion divided into dorsal and side areas ; insertion-plates sharp
and very long, that of the head valve with 7 to 8 irregularly placed slits ;
gills long and extending the whole length of the foot : 1 species.

K. tunicata (Wood). Shell dark brown; girdle black, shining and
leathery; length up to 75 mm.; breadth 40 mm.: Alaska to Catalina
Island, from low-water line to 20 fathoms; eaten by the Indians.

2. AMICULA Gray. Shell with the valves externally scarcely visible,
the exposed part being heart-shaped and as broad as long; hinder valve
with a median sinus and a slit on each side: 3 species.

A. vestita (Sowerby) (A. emersoni Couthouy) (Fig.
752). Length 50 mm.; breadth 35 mm.; color of shell light
drab; girdle brown, thin, and smooth, showing the valves
through it; adults with scattered tufts of hair: New Eng-
land coast north of Cape Cod in 5 to 30 fathoms.

3. CRYFTOCHITON Middendorff. Valves concealed by
the leathery girdle and lacking tegmenta, their hinder

margins produced backwards in a deep lobe on each side, the lobes fusing
across the median line: 1 species.

C. stelleri (Midd.). Body oblong, brick red in color; covered with
minute spines; length 20 cm.: Pacific coast, south to Monterey, Califor-
nia, just below low tide ; eaten by the Indians.

SUBORDER 3. TELEOPLACOPHORA.

Shell of large size; the anterior valve similar to the posterior, and
similarly articulated; insertion plates on all the valves, finely pectinated
or grooved, blunt-edged and slit, the teeth all projecting outwards: 10
genera and about 80 species, principally in the Pacific.

CHITON L. Girdle covered with imbricating scales ; no eyes present ;
gills extending the entire length of the foot: 36 species, principally in
the West Indies and the Pacific.

C. tuberculatus L. Shell green or olive brown in color, generally
spotted; lateral areas with 5 radiating ridges; central areas with longi-

490

MOLLUSCA

tudinal ridges ; up to 9 cm. long and 55 mm. wide : West Indies, Bermuda,
Florida, Texas; the commonest West Indian Chiton.

C. squamosus L. (Fig. 745). Shell greenish in color and with median
keel; central areas of shell longitudinally, lateral areas transversely
striated; length 8 cm.: Bermuda and West Indies; Europe.

CLASS 2. SCAPHOPODA.*

Bilaterally symmetrical, elongated mollusks enclosed in a tapering
cylindrical shell, which is open at the two ends and slightly arched, the
concave side representing the upper or dorsal side of the body (Fig. 753).
The mantle folds arise in the larva from the dorsal
surface of the very much elongated visceral mass and
fuse together ventrally, forming a cylinder open at
both ends. From the anterior and larger opening
projects the cylindrical foot (7) and a number of slen-
der tentacles (8). The mantle cavity is posterior in
position. The head is not developed, the mouth being
situated at the extremity of a cylindrical snout (5),
where it is usually surrounded by small leaf-like ten-
tacles, while from the base of the snout extend the
long slender tentacles above mentioned. No ctenidia
are present, the tentacles being possibly homologous
to them.

The mouth opens into a V-shaped intestine, in the
anterior portion of which is a jaw and a radula; the
anus is in the mantle cavity at the base of the foot.
The heart is rudimentary, no auricles being present.
The nervous system is well developed, paired cerebral,
visceral, pedal, pleural, and buccal ganglia being pres-
ent. No organs of special sense except lithocysts are
found. A pair of nephridia opens to the outside by
two pores near the anus. The sexes are separate, the single gonad dis-
charging its products through the right nephridium.

History. — The older authors called the scaphopods Tubulus marinus
or Denticulus elephantis, and placed them among the tubicolous annelids
with Serpula, or among the snails, in the neighborhood of Patella or of
Vermetus. In 1857 Lacaze-Duthiers placed the group under the Acephala,
maintaining that the twofold origin of the mantle showed a nearer rela-
tionship to bivalves than to snails. M. Sars and Bronn, however,

* See "Scaphopoda," by II. Simroth, Bronn's Klassen u. Ord. d. Thier, Vol. 3,
1 Abt, 356, 1894. "Scaphopoda," by H. A. Pilsbry and B. Sharp, Man. of Conch.,
Vol. 17, 1897.

Fig. 753 — Dia-
gram of Dentalium
(Lang). 1, gonad ;
2, shell ; 3, retrac-
tor muscle; 4,
anus ; 5, mouth ;

6, mantle cavity ;

7, foot ; 8, cephalic
tentacles.

SCAPHOPODA 491

retained them among the snails, largely because of the radula and jaw,
and in 1862 the latter author introduced the name Scaphopoda, but
for a long time the opinion prevailed that the true position of the group
was between snails and bivalves, and that they represented the
common ancestors of both. At present the latter view is not generally
held, and the systematic position of the Scaphopoda is still in dispute.
There can be do doubt, however, that they are very primitive mollusks
and so aberrant in structure that they should be placed in a Class by
themselves.

The Scaphopoda are all marine animals, living in clean sand in
various depths from shallow water to 2,600 fathoms; they are found in
all seas except the polar. About 200 species are known, grouped in two
families; about 350 fossil species are known.

Key to the families of Scaphopoda:

Oi Foot trilobate 1. DENTALIIDAE

at Foot elongate, vermiform 2. SiPHONODENTALriDAE

FAMILY 1. DENTALIIDAE.

Foot with 2 lateral epipodial lobes, making it trilobate; oral palps
present; lateral teeth of the radula dentate; width of the median tooth
of radula double its height : 6 genera and 50 species, most of which are
found in deep water.

DENTALIUM L. With the characters of the family: 9
subgenera and numerous species.

D. entale L. (Fig. 754). Shell not much curved,
glossy and ivory-like, annulated, without longitudinal stri-
ations except at the smaller end; 50 mm. long; 5 mm.
wide : Cape Cod to the Arctic Ocean, in 3 to 1,750 fathoms ; (Kfngsiey)
common; Europe.

D. pretiosum Sowerby. Like the above, but larger, slenderer, and
whiter; length up to 55 mm.; diameter 5 mm.: Pacific coast from Sitka to
Lower California.

D. occidentale Stimpson (D. dentale Gould). Shell curved like an
elephant's tusk, glossy, yellowish-white, with about 20 longitudinal stri-
ations, and about 25 mm. long and 8 mm. in diameter: New England
coast north of Cape Cod, in from 8 fathoms to deep water.

FAMILY 2. SIPHONODENTALIIDAE.

Foot vermiform, capable of expansion into a terminal disc; width of
median tooth much less than double its length: 5 genera and about 60
species, most of which are found in deep water.

492 MOLLUSCA

SIPHONODENTALITJM Sars. Smaller orifice of shell with 2 slight
notches on each side.

S. lobatum Sowerby. Shell smooth, shining, thin; 10 mm. long:
Arctic seas, south to New England; Europe.

CLASS 3. GASTROPODA.*

Snails. Asymmetrical mollusks with usually a spirally coiled shell,
a distinct head, and a broad, flat foot (Fig. 740, B).

External Structure.— The shell is a spiral cone (Fig. 772), the apex
of which represents the dorsal side of the animal. In most snails the
spiral twists to the right, and when the apex is uppermost the opening or
aperture of the shell will be on the right. In some, however, the twist
is normally to the left, and in the right-handed species occasional indi-
viduals are found which are left handed. The axis of the shell, around
which whorls are coiled is called the columella. When this axis contains
a cavity the space is called the umbilicus : sometimes it is partially filled
by a thickening called the callus. In certain species, as the slugs, the
shell is rudimentary or wanting, and in a few forms, as the limpet, is
conical without forming 'a spiral. In most prosobranchs and some
opisthobranchs the aperture of the shell is closed when the animal is
withdrawn within it by a disc called the operculum.

The head (Fig. 771) bears one or two pairs of tentacles and a pair
of eyes; at its forward end is the mouth, which, in many species, is con-
tained in a long proboscis. The foot represents the ventral side of the
body, and is large and has usually a broad sole fitted for creeping on flat
surfaces. In the pelagic heteropods and pteropods it is modified to form
the fins, and in certain species it is wanting. The foot may secrete a
great amount of slime, either from its entire surfaces or from localized
glands, which facilitates locomotion.

The visceral mass makes up the greater part of the spiral body, and
is covered by the mantle, which extends from the apex to the foot in a
single conical fold. The lower edge of the mantle is called the collar
(Fig. 771, 7) ; it can, in many prosobranchs be prolonged to form a
siphon. The shell is secreted by the mantle, and follows its spiral wind-
ings. The mantle unites with the visceral mass on all sides but one,
where a space called the mantle cavity is left between them. In certain
primitive snails this is posterior in position, but in the majority of them
it has shifted to the right or to the anterior side (Fig. 740,3). In the
mantle cavity are the gills or lungs, and in most snails the external open-

* See "The Mollusca of the Chicago Area : The Gastropoda," by Frank Baker,
Natural History Survey, Bull. Ill, Part II, 1902.

GASTROPODA 493

ings of the digestive, excretory, and genital organs. In some snails,
especially among the nudibranchs, the mantle is wanting; the shell is also
absent in these animals, and the gills, when present, are not homologous
to the ctenidia of other mollusks, but are simple outgrowths of the
integument of the back.

Internal Structure.— The spiral twisting of the visceral mass of most
snails has caused a displacement of the internal organs and the loss of
the left-hand member of the primitively paired ones. Thus, but a single
ctenidium, kidney, auricle, and osphradium are usually present, instead of
a pair. The mouth opens into the pharynx (Fig. 742), which contains
the tongue and the radula. In the roof of the pharynx and opposed to
the tongue are one or more cuticular plates called the jaws, against which
the radula is rubbed in the process of rasping. A pair of salivary
glands pour their secretion into the pharynx. The alimentary tract,
which consists of the oesophagus, the stomach, and the intestine, bends
on itself, the anus being not far from the mouth of the shell.

Three classes of respiratory organs are found — ctenidia, lungs, and
adaptive gills. In most cases ctenidia (Fig. 821) are present; pulmo-
nates, both aquatic and terrestrial, breathe by means of lungs; nudi-
branchs have neither ctenidia nor lungs, but in their place adaptive gills
(Fig. 765), which are projections of the dorsal body wall. A few nudi-
branehs do not possess these organs, but respire through the ciliated
integument. The heart bears a close relation to the gills. Certain primi-
tive snails, which possess a pair of ctenidia, have also two auricles, while
the majority of them, having but a single ctenidium, have also but one
auricle. Nudibranchs and pulmonates have also but one auricle. In the
opisthobranchs and the pulmonates the gills or lungs are behind, while
in the prosobranchs, as the name indicates, they are in front of the heart.

The excretory organs consist of a single kidney, which opens into
the mantle cavity near the anus; it also has a communication with the
pericardial (ccelomic) cavity. Those snails which have two ctenidia have
also a pair of kidneys.

The nervous system contains the characteristic ganglia. The cere-
bral ganglia are above and the pedal ganglia below the oesophagus and
united by commissures. The pleural ganglia are usually between and
joined with these two. The visceral ganglia lie below the intestine and
are joined with the pleural, and the parietal are near the visceral. In
the prosobranchs and in Acteon, 'an opisthobranch, and Chilina, a pulmo-
nate, the commissures joining the visceral with the pleural ganglia cross
each other in such a way that the nerve from the right pleural passes
over the intestine to the left side of the visceral. Those gastropods in
which this occurs are called streptoneurous ; the others are called euthy-

494 MOLLUSCA

neurous or orthoneurous. The sensory organs are a pair of eyes, one or
two pairs of tentacles, a pair of lithocysts in the foot, one or two osphradia
close to the ctenidia, and the rhinophores of the opisthobranchs, the last
two organs being olfactory in function. The osphradia are absent in most
snails, which lack ctenidia, but not in all. The rhinophores are the pos-
terior pair of tentacles of the opisthobranchs.

The single gonad empties its products in certain prosobranchs
(Patella) through the kidney, but in most gastropods through special
genital ducts, to the outside, the genital pore being in the mantle cavity
in prosobranchs and outside of it in opisthobranchs and pulmonates.
Most prosobranchs are unisexual, while the pulmonates and opistho-
branchs are hermaphroditic. The majority of snails are oviparous,
and many of them lay their eggs in protective capsules or a jelly;
a few are viviparous. Most marine snails leave the egg in the form
of the veliger larva; land snails lay eggs, which are covered with a
shell, in holes in the ground or similar places, and are born with the
form of the parent.

Distribution and Habits.— Most gastropods are aquatic animals, and
those which are terrestrial usually require a moist environment. A few
are parasitic, either on the outer surface (Stilifer) of star-fishes and other
animals or as internal parasites (EntoconcTia) in holothurians. Many are
of use to man, Helix pomatia, the imported, so-called French snail of the
New York markets, and many others, being used for food. The shells
also serve often for ornaments and are manufactured into buttons
and other articles. In Africa and other countries immense quantities of
cowries (Cyprcea moneta), and several other shells, are used as money.

History.— The class Gastropoda was created by Cuvier in 1795, who
included under it, among others, the orders Nudibranchiata, Tectibranch-
iata, and Pulmonata. The Pteropoda he created later, but as a separate
class equivalent to the Gastropoda. Lamarck in 1812 created the Hetero-
poda, and gave the group equal rank with the Gastropoda. Milne-
Edwards in 1846-1848 created the orders Opisthobranchiata and Proso-
branchiata. The Pteropoda were believed by Leuckart to be the ancestors
of the Cephalopoda, the arms of which he supposed to have come from
pteropod fins^ and Lankester has classified them under the Cephalopoda.
They were, however, universally placed in a class by themselves until
Pelseneer, in 1888, showed their affinities to the Opisthobranchiata. The
same author has also utilized the condition of the pleurovisceral connectives
in classification, dividing the Gastropoda into two groups, the Euthyneura,
with the Opisthobranchiata and Pulmonata, and the Streptoneura, with
the Prosobranchiataf a proceeding which has been adopted in some text-
books. The class contains 49,000 species, grouped in 3 orders.

GASTROPODA 495

Key to the orders of Gastropoda:
G! Land and fresh- water snails; lungs, and not gills, present; no oper-

CUlum 2. PULMONATA

aa Mostly aquatic snails with either ctenidia or adaptive gills.
&i Ctenidia posterior in position or adaptive gills present ; shells small

or wanting ; all marine 1. OPISTHOBEANCHIATA

63 Ctenidia at forward end of body ; shell well developed ; operculum usu-
ally present ; mostly marine 3. PBOSOBBANCHIATA

ORDER 1. OPISTHOBRANCHIATA.*

Sea slugs. Marine snails, in which the mantle and shell are either
entirely wanting, or when present are usually small. The body is asym-
metrical, the kidney and genital pores and usually the anus being on the
right side; in certain nudibranchs the anus is (secondarily) median and
posterior in position. The shell, when present, is usually a spiral. In the
nudibranchs the ctenidia and osphradia are absent, respiration being
effected either by the general surface of the body or by so-called adapt-
ive gills, which are projections of the dorsal body wall (Fig. 765). The
foot has usually a broad sole, but in the pteropods is highly modified, the
epipodia alone being well developed, forming a pair of fins, by means of
which the animal swims (Fig. 759). In many others also the epipodia
form extensive folds which cover the back or are used in many cases in
swimming (Fig. 769).

The nervous system is compact, the ganglia being usually near
together just behind the pharynx; the pleurovisceral connectives are not
crossed except in Act eon. Two pairs of tentacles are present, the anterior
pair being sometimes absent, the posterior pair (rhinophores) having
often a lamellar structure. The eyes are at the base of these posterior
tentacles. The radula contains numerous teeth, and the jaw is composed
usually of two pieces. The animals are hermaphroditic, the common
gonad being protandric ; in the lower opisthobranchs it is joined with the
genital pore by a single duct, but in the higher ones a distinct oviduct
and vas deferens are present. The auricle lies back of the ventricle and
receives blood from the gills, which are also mostly posterior in position.

The opisthobranchs are mostly littoral animals living under stones
or among seaweed, and feeding principally on animal food, and many are
brightly colored. The pteropods as well as representatives of several
other groups are pelagic. The order contains over 2,300 species, grouped
in 2 suborders.

Key to the suborders of Opisthobranchiata:

at Shell usually present ; gill in the mantle cavity 1. TECTIBRANCHIATA

aa Shell and mantle absent; adaptive gills on the back 2. NUPIBRANCHIATA

* See "Manual of Conchology," Vol. 15 and 16, by H. A. Pilsbry; 1893-1896.

496 MOLLUSC A

SUBORDER 1. TECTIBRANCHIATA.

Shell and mantle usually present; ctenidium usually present and on
the right side (Fig. 760, 1) : about 1,400 species, grouped in 3 divisions
and 25 families.

Key to the divisions of Tectibranchiata here described:

ctj With well-developed shell, sometimes internal 1. BULLOIDEA

a, Shell reduced or absent 2. APLYSIOIDEA

DIVISION 1. BULLOIDEA.

Shell either external or internal and well developed; head with a
broad dorsal disc, under which the tentacles, when present, are con-
cealed; epipodia usually present: 15 families.

Key to the families of Bulloidea here described :

G! Animals not pelagic ; no swimming fins.

&! Shell external, with a prominent spire. 1. ACTEONIDAE

62 Spire very low or sunken.
Cj Shell external.

di Radula absent 2. TOBNATINIDAE

d2 Radula present.

ex Cephalic disc not bifurcate .3. SCAPHANDBIDAE

ea Cephalic disc bifurcate 4. AKERIDAE

ca Shell internal 5. PHILINIDAE

oa Animals pelagic, with large swimming fins (pteropods).

61 Shell spiral, sinistral 6. LIMACINIDAE

62 Shell symmetrical and not spiral 7. CAVOLINIIDAE

FAMILY 1. ACTEONIDAE.

Shell external, with a prominent spire; epipodia absent, cephalic
disc divided behind; operculum horny; pleuro visceral nerve connectives
streptoneurous : 7 genera, mostly in warmer seas.

ACTEON Montfort. Shell solid, ovate; aperture nar-
row and one-half the length of the shell : 35 species.

A. punctostriatus (Adams) (Fig. 755). Shell conical,
with 2 or 3 color bands; aperture long and narrow;
P. 7gg inner lip with a strong tortuous fold; animal white;

to8t?iatlT' length 6 mm-: CaPe Cod to Florida, in 2 to 60
(Verrill). fathoms.

FAMILY 2. TORNATINIDAE.

Small external, more or less cylindrical, with the spire sunken or
short and elevated; head triangular or quadrangular; tentacles broad,
united at the base; eyes distinct; radula and epipodia absent: 3 genera
and 120 species.

1. BETTTSA Brown. Shell with a slightly raised or flat spire; aper-
ture nearly as long as shell, narrow above and dilated below: 50 species.

GASTROPODA

497

R. gouldi (Couthouy) (Fig. 756). Shell white and shining, with a
yellow periostracum ; spire conical; 7.5 mm. long; 2.5 mm. wide: Maine
to Cape Hatteras.

2. TORNATINA Adams. Shell with an elevated apex; inner lip with
fold; sature channeled: 50 species.

T. canaliculata (Say). Shell with a low spire, pol-
ished, with a channeled suture, white without spots ; length
5 mm. ; width 2.5 mm. : Atlantic coast south of Cape Cod,
in shallow water.

FAMILY 3. SCAPHANDRIDAE.

Fig. 756

Retusa gouldi

(Ball).

Shell external, ovate, spire sunken ; aperture narrowed
above; inner lip spirally convoluted; outer lip acute;
head broad and short; epipodia usually well developed; head quadran-
gular, with eyes at base of tentacular lobes: 6 genera.

1. DIAPHANA Brown. Shell thin and transparent; both inner and
outer lips sinuous ; epipodia wanting : species few.

D. debilis (Gould). Shell small, greenish-white, with 4 whorls, all
rising to the same height, partially umbilicated; 3.5 mm. long; 2.5 mm.
wide: Atlantic coast south to New Jersey, in 6 to 50 fathoms; Europe.

2. CYLICHNELLA Gabb. Tentacle lobes united and indistinct, with

eyes on their front base; shell solid, without spire:
40 species, mostly in deep water.

0. oryza (Totten) (Fig. 757). Shell white,
ovate; length 7 mm.; width 2.5 mm.: Maine to
Connecticut.

Fig. 757 Fig. 758

Fig. 757— Cylichnel-

la oryza (Verrill).

Fig. 758 — Haminea

isolitaria (Dall).

FAMILY 4. AKEEIDAE.

Shell external, fragile, light-colored, usually
covered by the large epipodia, cylindrical or ovate,
with a very small sunken spire and a large aperture with a sharp outer
lip: 5 genera and 70 species.

HAMINEA Leach. Shell unicolored, green, or yellow, thin and horny.
H. solitaria (Say) (Fig. 758). Shell ovate, 9 mm. long and 6 mm.
wide, shining, with deep, microscopic, impressed lines : common along the
Atlantic coast from Massachusetts Bay to South Carolina.

FAMILY 5. PHILINIDAE.

Shell internal, sometimes absent, convex, with a large aperture;
epipodia large and fleshy, folded over the back j head without tentacular
processes ; 4 genera,

498 MOLLUSCA

PHILINE Ascanias. Shell with a rudimentary spire, white, translu-
cent, oval; animals slug-like; radula with no central teeth; foot about
two-thirds the length of the body and obliquely truncated : 20 species.

P. quadrata (Wood). Shell 5 mm. long, 3.5 mm. wide, with 2 to 3
whorls, squarely globose: New England north of Cape Cod, in rather
deep water; Europe.

P. lima (Brown). Shell with 3 to 4 whorls, elongate, broadest ante-
riorly, 3.5 mm. long, 2 mm. wide, reddish in color: New England north
of Cape Cod; Europe.

FAMILY 6. LIMACINIDAE. (PTEROPODA THECOSOMATA.)

Shell and mantle present ; shell snail-like, minute, with a left-handed
spiral and an operculum ; ctenidium and eyes absent ; 1 pair of tentacles ;
mantle cavity, with anus and other openings on right side; 2 large fins
present, these being the epipodia, which have extended around the dorsal
side of the head : 2 genera and about 19 species, which are pelagic, prin-
cipally in the northern seas.

Fig. 759 Fig. 760 Fig. 761

Fig. 759 — Limacina arctica (Leunis). Fig. 760 — Cavolinia trispinosa (Dall). 1, gill,
Fig. 761— iCreseis conica (Dall).

LIMACINA Cuvier. Shell transparent, with a low spiral and a wide
umbilicus: several species in the Arctic and Antarctic seas, which form
an important food of whales.

L. arctica (Fabricius) (Fig. 759). Whorls of shell 6; spire low;
umbilicus wide ; width 4 mm. : Arctic seas, south to New Jersey.

FAMILY 7. CAVOLINIIDAE. (PTEROPODA THECOSOMATA.)

Shell and mantle present; shell not spiral, but symmetrical, straight
or curved, without operculum; ctenidium and eyes absent; 1 pair of ten-
tacles ; mantle cavity ventral ; 2 large fins present as in previous family :
about 50 species, all of which are pelagic.

1. CAVOLINIA Abildgaard (Hyalea Lamarck). Shell globular, with
3 long sharp spines posteriorly; aperture contracted with a slit on each
side, through which long appendages of the mantle pass : 10 species.

C. trispinosa (Lesueur) (Fig. 760). Length 10 mm.; median spine
as long as the body; lateral spines only a third as long: Atlantic coast.

GASTROPODA 499

2. CEESEIS Rang. Shell conical, slender, pointed, straight or
slightly curved: 6 species.

0. conica Eschscholtz (Fig. 761). Length 12 mm.; diameter 2 mm.:
Atlantic coast.

DIVISION 2. APLYSIOIDEA.

Shell reduced or absent ; head without cephalic disc and with 2 pairs
of tentacles; epipodia present, which arise from the sides of the body
and not the foot; osphradium present: 6 families, all but the Aplysiidae
being Pteropoda Gymnosomata, or shell-less pteropods.

Key to the families of Aplysioidea here described :

«! Shell present ; animals live on seaweed 1. APLYSIIDAE

a2 Shell absent ; animals pelagic (pteropods) 2. CLIONIDAE

FAMILY 1. APLYSIIDAE.

Sea hares. Body large; shell rudimentary and internal; animal
slug-like, with the anterior angles of the head extended into 2 large
tentacular folds, behind which are a pair of eyes and behind these the
rhinophores; epipodia, which are large lobes, turn up over the back:
7 genera and numerous species; cosmopolitan; mostly large, brightly
colored slugs, which secrete a reddish fluid from the mantle wrongly
supposed by many to be poisonous.

APLYSIA L. Animal swollen behind, with a long neck and head;
shell flexible; epipodia mobile and used for swimming: 50 species.

A. protea Rang. Length 16 cm.; color variable, yellow or green,
with ring-shaped spots of black, red, and green: common in the West
Indies, also on the Florida coast.

A. calif ornica Cooper. Length up to 37 cm.; color
gray or greenish, purple on the sides, covered with brown
lines and blotches; epipodia behind the middle: Monterey
to San Pedro.

FAMILY 2. CLIONIDAE. (PTEROPODA GYMNOSOMATA.)

Shell and mantle absent; body fusiform; head dis-
tinct, with 2 pairs of tentacles, the hinder of which bears
eyes ; foot represented by a pair of fins which spring from
the base of the neck; between the base of the fins the
rudiment of the median portion of the foot; gill absent;
proboscis generally with suckers or with lateral lobes which bear suckers :
14 genera; pelagic.

CLIONE Pallas. With the characters of the family: 10 species.

C. limacina (Phipps) (Fig. 762). Body tapering to a point behind,
35 mm. long, pale blue in color and hyaline; fins triangular: Arctic

500 MOLLUSCA

Ocean, south to New York; it swims about near the surface in immense
schools, sometimes coloring the sea for miles, and forms an important
source of food of whales.

SUBORDER 2. NUDIBRANCHIATA.

Sea slugs. Shell, ctenidium, and osphradium absent, but a coiled
shell is present in the embryo; respiration either through the integu-
ment, no gills being present, or by means of adaptive gills; these sur-
round the anus when it is median and dorsal in position, or form longi-
tudinal or transverse rows; in the latter case they are called cerata
and usually contain hollow extensions of the liver and also nematocysts,
which, however, are derived from ingested hydroids; 2 pairs of tentacles
present : about 1,000 species, grouped in 4 divisions and 19 families.

Key to the divisions of Nudibranchiata:

G! Cerata usually present ; anus lateral.

&! Cerata branched or foliaceous, in 2 rows 1. TRITONIOIDEA

62 Cerata simple or absent.

Cj Jaws present ; several rows of cerata on each side 3. ^BOLIDIODEA

c2 Jaws absent ; cerata usually absent 4. ELYSIOIDEA

a, Anus median and posterior, surrounded by a circle of adaptive gills.

2. DOBIDIOIDEA

DIVISION 1. TRITONIOIDEA.

Two longitudinal rows of branched cerata usually present, into
which the liver usually does not extend, and without nematocysts; anus
on right side: 7 families.

Key to the families of Tritonioidea here described :

at Two pairs of cerata 1. SCYLL^EIDAE

a. More than 2 pairs of cerata 2. DENDRONOTIDAE

FAMILY 1. SCYLL^EIDAE.

Body elongate, with a narrow foot; anterior tentacles absent; 2
pairs of branched, foliaceous cerata; male and female openings con-
tiguous: 1 genus.

SCYLLJEA L. Body narrow and compressed; oral tentacles want-
ing; rhinophores retractile: 8 species.

S. pelagica L. (8. edwardsi Verrill). Cerata spatula te, bearing small
tufted projections on the inner surface, similar projections being on
the back; foot very narrow; color brownish or orange, irregularly
spotted; length 75 mm.; width 12 mm.: pelagic, living on floating
seaweed.

FAMILY 2. DENDRONOTIDAE.

Body elongate; tentacles laminated and branched, forming fringed
frontal appendages; 2 rows of branched cerata on the back into which
the liver extends: 4 genera.

GASTROPODA 501

DENDRONOTUS Alder and Hancock. With the characters of the family.

D. arborescens (0. F. Miiller) (Fig. 763). Color pale or red with
brownish or whitish
spots; cerata trans-
parent, 5 to 7 on a
side ; length 8 cm. : on
rocks and seaweed ;
circumpolar, south to
Rhode Island ; com-
mon in Casco Bay; Fig. 763 — Dendronotus arborescens (Gould).
Europe.

DIVISION 2. DOEIDIOIDEA.

Anus median and posterior and surrounded by a circle of adaptive
gills into which the liver does not extend: 5 families.
Key to the families of Doridioidea here described :

at Mantle with lateral tubercles or appendages 1. POLYCERIDAE

aa No lateral tubercles or appendages 2. DORIDIDAE

FAMILY 1. POLYCEEIDAE.

Body elongate, with a marginal ridge on each side bearing tubercles
or appendages; integument with spicules; rhinophores not retractile and
usually lamellate ; gills non-retractile and with lateral projections : about
8 genera.

Key to the genera of Polyceridae here described:

a^ Marginal ridge with short tubercles of nearly equal length 1. POLYCERA

ca Marginal ridge with long appendages, some at base of rhinophores.

2. ANCULA

1. POLYCERA Cuvier. Body limaciform; mantle indistinct, forming
a projecting frontal velum and a tuberculated ridge along each side:
11 species.

P. lessoni D'Orbigny. Length 30 mm.; color greenish; about 6

long, finger-like tubercles on a side, tipped with yellow; a median row

of tubercles also present; head with 6 projecting points on each side:

Long Island Sound and northwards; Europe; common in Casco Bay

from low water to 20 fathoms.

2. ANCULA Loven. Body limaciform and
smooth ; head bearing tentacular projections at the
base of the rhinophores as well as one at side in
front, and also several surrounding the gills: 3
species.

A. sulphurea Stimpson (Fig. 764). Body slender, 30 mm. long,
light brownish and transparent; rhinophores club-shaped; 3 branched,

502 MOLLUSCA

pinnate gills, surrounded by 8 to 12 long projections; all tentacles and
projections tipped with yellow: New England north of Cape Cod, often
common under stones.

FAMILY 2. DOBIDIDAE.

Mantle large, covering the head and without marginal appendages;
integument generally very spiculose; rhinophores laminate and retrac-
tile; anterior tentacles small; gills usually retractile: 9 genera.

Key to the genera of Dorididae here described :

G! Gills retractile ' 1. DORIS

a. Gills not retractile.

&! Gills pinnate and simple 2. ONCHIDORIS

&a Gills bipinnate 3. ACANTHODORIS

1. DORIS L. Body depressed, often with dorsal tubercles; gills
branched or feathered, united at the base, and retractile; mouth with 2
oral lobes: 150 species; cosmopolitan.

D. repanda Alder and Hancock. Body broad, light-
colored, covered with minute white tubercles; mantle ex-
panded beyond the foot ; gills form a star of about 10 pin-
nate plumes ; length 15 mm. ; width 12 mm. : New England
north of Cape Cod, under stones at low-water line ; Europe.

D. bifida Verrill (Fig. 765). Body broad and oval,
purplish-brown in color, speckled with white, 25 mm. long,
12 mm. wide ; back very convex, with papillae ; gills with 7
Doris Wflda bipinnate plumes : New England from Long Island Sound
to Eastport, under stones at low-water mark.

2. ONCHIDORIS Blainville. Body depressed; head with a veil in
place of oral tentacles; gills pinnate, set in a circle and non-retractile:
23 species.

0. bilamellata (L.). Body elliptical, brownish or pink in color,
covered with short, unequal papillae; gills 20 to 25 in number, slender
and arranged in an oval; length 25 mm.; width 12 mm.: Atlantic coast,
north of Cape Cod; often common; Europe.

0. pallida (Agassiz). Body elongate, cream-colored, covered with
large mushroom-like tubercles; gills form a star of 7 or 8 broad plumes,
which are retractile; 12 mm. long, 6 mm. wide: Cape Cod northwards,
from low-water mark to 30 fathoms; Europe.

3. ACANTHODORIS Gray. Body convex, covered with soft papillae;
oral lobes united to form a veil; gills united at the base and non-
retractile: 4 species.

A. stellata Verrill. Body broad, narrower behind, covered with
small pointed papillae; gills composed of 7 bipinnate plumes; color

GASTROPODA 503

variable, often purplish; length 25 mm.; width 12 mm.: Long Island
Sound and northwards, under stones at low-water mark.

DIVISION 3. ^GOLIDIOIDEA.

Simple unbranched cerata on each side, into which liver projections
extend and which often contain nematocysts; anus usually on right
side: 9 families.

Key to the families of ^Eolidioidea here described :

fli Numerous cerata, in transverse rows 1. JEoLiDiDAE

a2 One longitudinal row of cerata on a side 2. DOTONIDAE

FAMILY 1. ^OLIDIDAE.

Cerata arranged in transverse rows along the body, which contain
nematocysts, which, however, have been introduced with the hydroids
on which the animals feed; no spicules in integument and no mantle;
tentacles non-retractile; anus on the right side: 100 species, the animals
feeding largely on hydroids and bryozoans.

Key to the genera of JEolididae here described:

Oj Body broad, being at least a third as broad as long 1.

fl-a Body usually less than a quarter as broad as long.
&! The 2 pairs of tentacles unequal in length.

G! Front angles of foot not prolonged 2.

c3 Front angles of foot prolonged 4. COBYPHELLA

62 The 2 pairs of tentacles of equal length 3. FLABELLINA

1. JEoLis Cuvier. Body ovate; cerata cylindrical and numerous,
extending along the entire back; 2 pairs of cylindrical tentacles:
numerous species.

A. papillosa (L.) (Fig. 766). Body broad, depressed,
tapering behind, gray or orange-colored, spotted with
brown or white; cerata crowded, arranged in 12 to 20
imbricated oblique rows on each side and 10 or 12 in
a row; length 7 cm.; width one-third the length: Rhode
Island to Arctic Ocean, among hydroids and under stones
between tide lines ; Europe.

2. ^OLIDIA Cuvier. Tentacles of unequal length;

Fig. Too

cerata compressed, in transverse, rather distant rows: 4 JKolis papillosa

(Gould),
species.

A. pilata (Gould). Body elongate, 38 mm. long, 6 mm. wide, pale
drab in color with a mid-dorsal, interrupted carmine stripe margined
with silvery dots; cerata fusiform, in 5 groups: Long Island Sound to
Massachusetts Bay.

A. diversa (Couthouy). Body elongate, tapering to a point, pale
yellow in color; oral tentacles long and slender; dorsal tentacles shorter;

504 MOLLUSCA

cerata fusiform with an orange-colored interior, arranged in transverse
groups of 3 or 4; length 30 mm.; width 8 mm.: Cape Cod, northwards.

3. FLABELLINA Cuvier. Body slender; rhinophores laminated; oral
tentacles elongate; cerata on compressed stalks: several species.

F. bostoniensis (Couthouy). Body drab in color with a silvery line
on the tail and the back of the oral tentacles; cerata curve backwards,
arranged in 5 or more groups on each side, white-tipped ; length 25 mm. ;
width 7 mm.: Cape Cod and northwards.

4. CORYPHELLA Gray. Front angles of foot elongated to form long
lobes: 18 species.

C. gymnota (Couthouy). Body slender and tapering to a point,
white in color ; oral tentacles longer than the dorsal, which have wrinkled
sides; cerata arranged in 6 to 10 transverse clusters, with a vermillion
interior and white tips; length 25 mm.; width 3 mm.: Woods Hole to
Boston.

C. mananensis (Stimpson). Body white in color; cerata vermillion
with white tips; rhinophores brown and wrinkled; length 35 mm.: Cape
Cod and northwards.

FAMILY 2. DOTONIDAE.

Cerata tuberculated and in a single row on each side, numerous,
without nematocysts; tentacles retractile; foot very narrow; a simple
veil in front : 4 genera.

DOTO Oken. With the characters of the family: 4 species.

D. coronata (Gmelin) (Fig. 767). Body slender;
brown or pink in color, but variable; 12 mm. long;
cerata large, club-shaped, 5 to 8 on a side, with red
spots: New Jersey to Labrador in shallow water, on
Bryozoa and hydroids; often common.

DIVISION 4. ELYSIOIDEA.

Fig. 767
Doto coronata Cerata either present, when they receive extensions

A, dorsal as- of the liver, or absent ; laws absent ; radula with but
pect ; B, one
of the cerata. one row of teeth : 3 families.

Key to the families of Elysioidea:

Cj Cerata present ir HEBM^IDAE

aa Cerata absent.

&! Two lateral ridges present 2. ELYSIIDAE

6, Ridges absent 3. LIMAPONTIIDAE

FAMILY 1. HERM^IDAE.

Cerata present; 1 pair of tentacles, non-retractile or absent; anus
dorsal and median: 4 genera.

GASTROPODA 505

1. ALDERIA Allman. Body elongate, without tentacles; head with
lobes at the side; anus dorsal, posterior: 4 species.

A. harvardiensis (Agassiz) (Fig. 768). Body square and broad in
front, tapering behind; cerata short, arranged in 6 or 7 clusters on each
side with 2 in each cluster; color brownish-yellow; length 12 mm.;
width 4 mm.: in shallow pools, north of Cape Cod; often common.

2. TERGIPES Cuvier. Foot rudimentary; cerata in a single row
on each side; tentacles cylindrical: several species.

T. despectus Johnston. Four club-shaped cerata on each side ;
dorsal tentacles long, oral tentacles short: Long Island Sound north-
wards; often abundant on hydroids in shallow water.

FAMILY 2. ELYSIIDAE.

Body without cerata, but ciliated, and with 2 lateral ridges, con-
taining hepatic caeca; radula with a single series of strong teeth; eyes
on the sides of the head; anus median or latero-dorsal : 15 species.

Fig. 768 Fig. 769 Fig. 770

rvardiensis (Gould). Fig. 769 — 1
Fig. 770 — Elysia catula (Gould).

Fig. 768 — Alderia harvardiensis J Gould). Fig. 769 — Elysia chlorotica (Gould).

" i (G

1. ELYSIA Risso. Body elliptical, depressed; wing-like ridges wide;
2 rather short, thick tentacles: 7 species.

E. chlorotica (Agassiz) (Fig. 769). Body slender, bright green in
color, dotted with white and red spots, 40 mm. long, 8 mm. wide; ridges
broad, folding over the back, overlapping when the animal crawls, and
expanded, leaf-like, when it swims: New Jersey to Boston, in shallow
and brackish water; often abundant.

E. catula (Ag.) (Fig. 770). Body elongate, brownish-green in
color, with a few whitish spots, 6 mm. long and 2 mm. wide ; ridges when
folded do not overlap: New Jersey to Boston; common among eel
grass and shallow water.

FAMILY 3. LIMAPONTIIDAE.

Body minute without lateral expansions or cerata; sides of head
with ridges; anus median and posterior: 6 species.

LIMAPONTIA Johnston. Eyes on the lateral cephalic crests: several
species.

506

MOLLUSCA

L. zonata (Girard).
bands: Massachusetts.

Body reddish in color with transverse white

ORDER 2. PULMONATA.*

Fresh-water and land snails (Fig. 771). Small snails, in most of
which the shell is a simple, regular spiral. The aperture of the shell (Fig.
772) is more or less circular or crescentic and usually rather small, and is
sometimes contracted by the presence of teeth or lamellae (7). It has an
outer lip or peristome (4) which is either acute or expanded, and an inner
or parietal lip (towards the axis of the shell) which may be either thick-
ened or not. Arion and Limax have no outer shell, but rudiments of one
are embedded in the wall of the mantle, while Pliilomycus is altogether
shell-less. An operculum is not found, but many land snails close the
aperture, on beginning thei'r hibernation, by means of a partition of cal-

Fig. 771 Fig. 772

Fig. 771 — Helix aspersa (Lang). 1, genital pore; 2, posterior tentacle, with an
eye at its tip ; 3, anterior tentacle ; 4, pedal gland ; 5, respiratory pore ; 6, anus :
7. collar. Fig. 772 — Diagram of a pulmonate shell (Walker). 1, suture; 2, apex;
2-8, height or length of shell ; 3, spire ; 4, lip ; 5-10, width of shell ; 6, aperture ;
7, parietal tooth ; 9, umbilicus.

cified slime called the epiphragm. The mantle cavity has an anterior
position, except in the Onchidiidae, the opening to the outside being a
small pore on the right side of the body (Fig. 771, 5), which can be closed
at will in order to keep out the water in the aquatic species and prevent
desiccation in the terrestrial ones. Ctenidia are not present and aerial
respiration is carried on by the vascular inner lining of the mantle cavity.
The aquatic species are no exception to this rule, but must in most cases
come to the surface of the water to obtain atmospheric air; young indi-
viduals, however, and the adults of a few species which live in the depths
of deep lakes, take water into the mantle cavity, and thus respire.

The head bears either one or two pairs of tentacles. In the aquatic
pulmonates but one pair is present (Fig. 776), which are not hollow or
retractile and have a pair of eyes at their base ; while the land pulmonates
have two pairs of tentacles (Fig. 771), at the tips of the posterior
and larger pair of which are the eyes. The jaw is composed of either

* See "Land and Fresh-Water Shells of North America," Parts 1 and 2, by W. G.
Binney, Smithsonian Misc. Coll., No. 143 and 194, 1865. "Manual Am. Land Shells,"
by same, Bull. 28, U. S. Nat. Mus.. 1885.

GASTROPODA 507

a single or of several pieces, but never of two symmetrical pieces; the
radula is broad, often nearly as broad as long, with many transverse
rows of very numerous teeth. These rows are either straight, curved, or
angulated. The pulmonate tooth has a broad base and a recurved and
either spine-like or dentate crown.

The pulmonates are hermaphroditic animals, a single protandric gonad,
the hermaphroditic gland, being present. The aquatic forms have two
genital pores, while most land pulmonates have but one. The genital
tract is considerably more complex in some forms than in others. A few
snails bear living young, but most of them lay eggs, those of the land
forms having calcareous shells and being deposited in the ground and
other moist places, while those of the aquatic forms are surrounded by a
transparent jelly.

The majority of the Pulmonata live on the land, either on the ground
among decaying leaves, in rotting wood, or in other dark moist place*, or
sometimes among the foliage of trees and shrubs. The aquatic forms are
found on- vegetation or on muddy or sandy banks in streams and fresh-
water ponds and lakes; a few are marine. A few pulmonates are car-
nivorous, feeding on other snails and other small animals, but the great
majority live on vegetable substances. About 19,000 species of pulmonates
are known, which are grouped in two suborders.

Key to the suborders of Pulmonata:

«! Aquatic pulmonates ; but 1 pair of tentacles 1. BASOMMATOPHOBA

a, Land pulmonates ; 2 pairs of tentacles 2. STYLOMMATOPHOBA

SUBORDER 1. BASOMMATOPHORA.

Fresh-water, or in a few cases marine or terrestrial, snails with
but 1 pair of tentacles (Fig. 776), which are solid and usually flattened,
and at the base of which are a pair of eyes; shell delicate, usually with
a conical spire and a large aperture ; 2 genital pores, usually on the right
side of the body, the male opening near the tentacle, the female opening a
little farther back, near the respiratory opening; ureter passes directly
forward from the kidney (Orthurethra) : cosmopolitan, there being about
4,000 species, grouped in 11 families.

Key to the families of Basommatophora here described:

ax Shell spiral.

&! Inner lip of aperture toothed 1. AURICULIDAE

l>2 Lip smooth.
cx Spire raised.

<?! Shell right-handed 2. LYMN^EIDAK

d2 Shell left-handed 3. PHYSIDAE

c3 Spire discoid 4. PLANOBBIDAE

o, Shell conic, not spiral .5. ANCYLIDAE

508 MOLLUSCA

FAMILY 1. AUBICULIDAE.

Shell spiral with a horny periostracum ; lower whorl usually very
large with an elongated aperture which has folds on the parietal wall and
usually teeth on the outer lip; head projects snout-like in front of the
cylindrical tentacles: several hundred species, which live largely in salt
marshes, principally in tropical countries; about 20 American species.

Key to the genera of Auriculidae here described :

d Spire of shell at least as long as its aperture.

6j Shell not minute 1. PHYTIA

6a Shell minute 2. CABYCHIUM

o. Spire much shorter than the aperture 3. MELAMPUS

1. PHYTIA Gray. Shell conical with a pointed spire; aperture with
1 to 5 teeth on the parietal wall; jaw slightly arched, smooth, with a
slight median projection; foot with a transverse groove: several species,
principally Mediterranean, 1 American.

P. myosotis (Draparnaud) (Fig. 773). Height 8 mm.; diameter 4
mm.; horn-color with a reddish sutural line: marine; Nova Scotia to

Fig. 773 Fig. 774 Fig. 775

Fig. 773 — Phytia myosotis (Verrill). Fig. 774 — CarycMum exiguum (Baker).
Fig. 775— Melampus lineatus—a. banded individual (Verrill).

Chesapeake Bay, also at San Francisco, near high-water mark along the
shore, being common in crevices of wharfs; an European species, perhaps
imported.

2. CAEYCHITTM 0. F. Miiller. Shell very thin and like a Pupa in
form; aperture oval with 1 or 2 teeth on parietal wall; jaw smooth:
about 15 species, principally European; terrestrial.

0. exiguum (Say) (Fig. 774). Height 1.75 mm.; diameter .75 mm.;
color of shell white, with 4l/2 whorls: under and in logs and moss in
moist places in eastern and central states; Oregon; common.

3. MELAMPUS Montfort. Shell with a very short, blunt spire and a
very large lower whorl; aperture long and narrow; inner lip with
several transverse folds; outer lip acute: 120 species, mostly tropical;
amphibious or found in brackish water; 4 American species.

M. lineatus Say (Fig. 775). Shell 13 mm. long and 7 mm. thick,
horn-color or reddish-gray, with 4 or 5 revolving bands when young,
aperture with a white callus and a prominent tooth on the parietal wall :
among the grass of salt marshes, near high- water line, from New England
to Texas; common.

GASTROPODA 509

FAMILY 2. LYMN^EIDAE.*

Shell thin, usually with a prominent acute spire and a large, often
flaring aperture, varying from horn-colored to black; lip acute and
simple; parietal wall of aperture with a white callus which entirely or
partially covers the umbilicus; tentacles flattened; eggs laid in a jelly;
radula with unicuspid central tooth: several genera with several hun-
dred species, inhabiting ponds, swamps, and streams in all parts of the
globe, but principally in temperate regions; about 35 species in the
United States.

LYMNJEA Lamarck. Jaw composed of 3 pieces, 1 large transversely
elongate piece and 2 small ones; foot rounded behind: over 200 species,
65 American.

Key to the species of Lymncea here described:
»! Shell more than 25 mm. long.

&! Spire long and slender L. STAGNALIS

&2 Spire short.

(?! Aperture about half the length of the shell L. MEGASOMA

c2 Aperture almost or quite as long as the shell L. AUBICULABIA

a, Shell less than 20 mm. long.

&! Aperture about half the length of the shell or longer.
G! Shell with 4 whorls.

dv Parietal callus straight L. COLUMELLA

d2 Parietal callus with a slight fold or angle in the middle. . .L. CATASCOPIUM
c2 Shell with 5 or 6 whorls.

di Shell 15 mm. long L. OBBUSSA

da Shell 8.5 mm. long L. HUMILIS

62 Aperture less than half the length of shell.

cx Shell very long and slender, aperture elongate L. BEFLEXA

c3 Shell not unusually slender.

</! Shell 30 mm. long or less L. PALUSTBIS

da Shell 15 mm. long or less with heavy spiral lines L. CAPEBATA

L. stagnalis (L.) (Fig. 776). Spire of shell long and slender, with
an acute apex ; aperture flaring ; whorls 6 ; length 60 mm. ; width 25 mm. :
circumpolar, being found in the northern states from the Atlantic to the
Pacific; often common in ponds; the largest species; Europe.

L. columella Say. Shell extremely thin and fragile, greenish or
yellowish in color, with 4 whorls, of which the last is large and forms
nearly the whole shell; length 17 mm.; width 6 mm.; aperture ovate:
central and eastern states; often common in stagnant and miry pools
and streams.

L. megasoma Say. Shell thick, with a short spire; length 40 mm.;
thickness 25 mm.: northern states from Vermont to Michigan.

L. reflexa Say (Fig. 777). Shell long and slender, fragile, with 6
to 7 whorls; aperture rather narrow; length 40 mm.; width 13 mm.:

* See "Lymnseidae of North and Middle America," by F. C. Baker, Chicago
Acad. Sci., Special Pub. No. 3, 1911.

510 MOLLUSCA

northern states from New York to the Pacific, also in the middle central
and western states; often common.

L. palustris (0. F. Miiller) (L. elodes Say) (Fig. 778). Shell from
pale brown to black in color, elongate, conical, with an acute apex which
is sometimes broken off and with rather more than 6 whorls, which are
decidedly convex; aperture shorter than the spire with an acute lip and
a white callus on the parietal wall; length 30 mm.; width 12 mm.:
circumpolar; northern America; the commonest species; Europe.

L. obrussa Say. Like the above, but shell with only 5 whorls and
a larger aperture, and very much smaller: New England to Kansas;
California; common about the muddy margins of ponds.

Fig. 776 Fig. 777 Fig. 778

Pig. 776 — Lymncea stagnalis (Baker). 1, foot; 2, tentacle. Fig. 777 — Lymncea reflexa
(Baker). Fig. 778 — Lymncea palustris (Baker).

L. catascopium Say. Shell broad and robust, usually reddish or
blackish with 4 to 5 whorls, the last large and very convex, with a large,
flaring aperture; length 17 mm.; width 12 mm.: northern and central
states; common in large rivers and lakes.

L. humilis Say. Shell small, thin, and transparent, with 5 or 6
whorls, 8.5 mm. long, regularly conical and somewhat elongate, variable
in color, sometimes blackish; distinct umbilicus present: entire eastern
and central America, on the muddy banks of streams.

L. auricularia (L.). Shell large, with a very short, acute spire
and a very large, ear-shaped aperture, which takes up almost the whole
shell; length 33 mm.; width 25 mm.: an European species, introduced
locally in many eastern localities.

L. caperata Say. Shell rather solid, yellowish to black in color,
with 5 to 6 whorls, with numerous minute revolving lines, 15 mm. long,
7 mm. wide: New England to California and northwards.

FAMILY 3. PHYSIDAE.

Shell sinistral, thin, with an acute spire, a large lower whorl, and a
large oval aperture, with an acute lip and a wide callus on the parietal
wall; jaw a single piece, foot pointed behind; tentacles filiform: over
150 species; cosmopolitan; about 22 in this country; in swamps and
ponds.

GASTROPODA 511

Key to the genera of Physidae here described :

Oj Margin of mantle digitate 1. PHTSA

<za Margin of mantle simple 2. APLEXA

1. PHYSA* Draparnaud. Mantle reflected over a portion of the
shell and fringed with finger-like filaments: 100 species.
Key to the species of Physa here described :

«! Whorls 5 or 6.

bi Aperture three-fourths the length of shell or more P. SAYI

63 Aperture two-thirds the length of shell or less P. GYBINA

a, Whorls about 4.

6X Spire very short P. ANCILLARIA

6a Spire acute P. HETEROSTKOPHA

P. sayi Tappan. Shell with 5 or S1/^ whorls, with an elevated, acute
spire and writh numerous impressed spiral lines; aperture large, three-
fourths or four-fifths the length of the shell; length 22 mm.; width 13.5
mm. : northern states, west to Rocky Mountains, south to Ohio River.

Fig. 779 Fig. 780

Fig. 779 — Physa gyrina (Baker). Fig. 780 — Physa heterostropha (Baker).

P. gyrina Say (Fig. 779). Shell an elongate cone with 5 or 6 whorls,
with numerous impressed spiral lines; aperture more than half but less
than two-thirds the length of the shell; length 23 mm.: Mississippi valley,
the commonest species in the central states.

P. ancillaria Say. Shell with 4 or 5 whorls, a very short spire, and a
very large bulging lower whorl; aperture almost as long as the shell;
color pinkish or yellowish ; length 14 mm. ; suture inconspicuous : eastern
and northern states, often common.

P. heterostropha (Say) (Fig. 780). Shell smooth and polished and
without spiral lines, with 4 whorls, the first very large, the others very
small, with an acute apex ; aperture large, elongate, and three-fourths
the length of the shell; color yellowish-brown or blackish; length 14
mm.; breadth 8.5 mm.: entire country; the commonest species in the
eastern states.

2. APLEXA Fleming. Mantle not reflected over the shell and with
a simple edge : several species.

* See "A Revision of the Physae of North Eastern Illinois," by F. C. Baker,
Nautilus, Vol. 14, p. 16, 1900. "The American Fhysae," by O. A. CrandaH, Nautilus,
Vol. 15, Nos. 3, 4, 5, 6, 1901.

512 MOLLUSCA

A. hypnorum (L.) (Physa elongata Say) (Fig. 781). Shell elongate,
with 6 whorls, yellow or brown in color, 17 mm. long and 8 mm. wide;
aperture narrow, about half the length of the shell : circuni-
polar; on muddy bottoms.

FAMILY 4. PLANOEBIDAE.

Shell sinistral and discoidal, having a flat or depressed

Fig. 781 spire, in some cases apparently dextral ; tentacles fili-

Aplexd
hypnorum form; radula with biscuspid central teeth; genital pores

on the left side; jaw composed of 3 pieces: 170 species; in
streams, ponds, and lakes, on muddy bottoms or on submerged objects
or vegetation.

Key to the genera of Planorbidae here described:
ot Interior of whorls without teeth 1. PLANORBIS

1. PLANORBIS L. Shell discoidal and sinistral, the spire being flat-
tened or sunken, with 3 to 5 whorls; umbilicus large and wide; lip simple
and acute: over 150 species; cosmopolitan, but found mostly in temperate
regions ; 26 American species.

Key to the species Planorbis here described :

G! Shell sinistral and about 12 mm. wide or more.

6t Aperture not flaring P. TBIVOLVIS

ft, Aperture flaring.

ct Keeled on both sides P. BICABINATUS

ca Keel on one side P. CAMPANULATUS

ffi2 Shell apparently dextral and about G mm. wide.

6a Periphery acutely keeled P. EXACUTUS

6a Periphery rounded.

G! Aperture deflected upwards P. DEFLECTUS

ca Shell hirsute P. HIRSUTUS

fy Shell regular and smooth P. PARVUS

P. trivolvis Say (Fig. 782). Shell sinistral, yellowish or brown,
with 4 whorls; spire sunken; aperture large, with a sharp and simple
lip, which has a V-shaped angle above; umbilicus
showing almost all of the whorls; height 9 mm.;
width 22 mm. : North America ; the commonest species.

P. bicarinatus Say. Shell sinistral, deeply con-
cave on both sides, pale yellow or brown, with 3

Fig. 782

whorls, 6 mm. high and 12 mm. broad, keeled on both Planorbis trivolvis

(Baker).

sides ; aperture large : northern and central states ; A, upper surface ;

. B, under surface,

south to Georgia and Kansas; California.

P. campanulatus Say. Shell sinistral, flat, with 4 whorls; aperture
flaring and bell-shaped; height 7 mm.; breadth 14 mm.: northern and
central states.

GASTROPODA 513

P. exacutus Say (Fig. 783). Shell apparently dextral, with an acute
periphery, 4 whorls, white or light yellowish in color; 6 mm. wide:
northern states, south to Kansas.

P. deflectus Say (Fig. 784). Shell apparently dextral, with a blunt
keel at the periphery, and 4 whorls, the largest whorl being deflected
from the plane of the others: North America, south to Washington.

Fig. 783 Fig. 784 Fig. 785

Fig. 783 — PlanorMs exacutus (Baker). Fig. 784 — PlanorUs deflectus (Baker).
Fig. 785 — PlanorMs parvus (Baker).

P. hirsutus Gould. Shell brownish, with 3 whorls; surface beset
with revolving lines of delicate hairs; aperture large and very oblique;
diameter 5 mm.: circumpolar; south to Washing-ton.

P. parvus Say (Fig. 785). Shell apparently dextral, with a rounded
periphery and yellowish to blackish in color, with 4 whorls; 5 mm. in
diameter; periphery rounded: North America; very
common, especially on water plants.

2. SEGMENTINA Fleming. Shell sinistral, discoidal,
with a flattened or sunken spire, furnished internally
with transverse partitions or teeth ; lip simple : but few SegmenUna

QF1fl>'l(j€TQ> (i->3.kGr).

species, principally in the Old World.

S. armigera (Say) (Fig. 786). Shell flat on the upper and concave
on the lower side, with 4 whorls; 5 internal teeth present, far within
the aperture, which nearly close the passage; diameter 6 mm.; height
2.5 mm.: North America; often abundant; sometimes gregarious.

FAMILY 5. ANCYLIDAE.

Shell thin, non-spiral, conical, with the apex median or directed to
the right, and an oval aperture; jaws 3, covered by papillae; tentacles
triangular, with eyes at their base: 8 genera and about 60
species; cosmopolitan.

ANCYLUS Geoffroy. River limpets. With the characters
above given: 16 American species.

A. parallelus Haldeman. Shell elongate, with the sides
Fig. 787 parallel and the ends blunt, with apex nearly in the center,
rivuiarte dark green in color; 5 mm. long and half as wide: New

England, on stones and leaves in brooks and ponds.
A. rivularis Say (Fig. 787). Shell oval, horny, white within, 6
mm. long; apex obtuse, nearer to and leaning towards one side and one
end: eastern states, sometimes common on dead shells and stones.

514 MOLLUSC A

SUBORDER 2. STYLOMMATOPHORA.*

Land snails with 2 pairs of retractile tentacles, the hinder and larger
pair bearing a pair of eyes at their tips (Fig. 771) ; shell absent or con-
cealed in the slugs, and in the other forms usually with 4 to 6 whorls
which form a more or less conical spire (Fig. 772) ; respiratory pore on
the right side of the body (Fig. 771, 5), with the anal and excretory pores
near it; either 2 (Ditremata) genital pores or 1 (Monotremata) ; in the
latter case, which characterizes all the American families except the
Onchidiidae, the pore is near the base of the right hinder tentacle (Fig.
771, 1) ; ureter passes either directly forward from the kidney towards
the anterior margin of the lung (Orthurethra), or is reflexed, passing
first to the posterior end of the lung cavity (Sigmurethra) : about 20
families, with about 15,000 species. The American forms fall into several
distinct groups. These are (1) the indigenous American snails, including
almost all those species occurring east of the Sierra Nevada and Cascade
mountains; (2) the boreal species, certain small northern forms of cir-
cumpolar distribution; (3) the Pacific slope species, which have migrated
there from Asia by way of Alaska; (4) the European species, introduced
by human agency; and (5) the southern species, which have entered the
country from Central America and the West Indies.

Key to the families of Stylommatophora here described:

Oi Shell present.

Z>! Shell with a high spire, being conical or cylindrical, not heliciform
(except Strobilops) .

G! Shell more or less cylindrical, pupiform (Fig. 788) 2. PUPILLIDAE

ca Shell conical ; with an acute apex.
d{ Jaw present.

e^ Spire very small, composed of 2 or 3 whorls 5. SUCCINEIDAE

e, Spire high, composed of 5 or more whorls.

A Jaw smooth ; shell glossy 3. COCHLICOPIDAE

/a Jaw ribbed ; southern animals 8. BULIMULIDAE

dt Jaw absent 10. OLEACINIDAE

5a Shell heliciform (Fig. 772) or depressed (except 8 phy radium) .
G! Shell with a wide lip.

di Shell minute, less than 3 mm. in diameter 4. VALLONIIDAE

d2 Shell not minute, more than 6 mm. in diameter 6. HELICIDAE

ct Shell with a thin lip.

</! Jaw without a median projection 7. ENDODONTIDAE

d3 Jaw with a median projection.

ej. Teeth of radula thorn-shaped, in V-shaped rows 9. CIRCINARIIDAE

e3 Teeth both thorn-shaped and bicuspid and in straight rows. . 11. ZONITIDAE

* See "Nomenclature and Check List of North American Land Shells," by H. A.
Pilsbry, Proc. Acad. Nat. Sci., Phila., 1889, p. 191. "Preliminary Outline of a New
Classification of the Helices," by H. A. Pilsbry, same, 1892, p. 387. "Guide to the
Study of the Helices/' by H. A. Pilsbry, Vol. 9, Ser. 2, Man. of Conchology, 1894.
"A Classified Catalogue of Am. Land Shells with Localities," by H. A. Pilsbry,
Nautilus, Vol. 11, pp. 45 et seq., 1897-98. "On the Zool. Position of Partula and

GASTROPODA 515

ia External shell absent ; slugs.

bL Animals marine 1. ONCHIDIIDAE

62 Land animals.
Cx Mantle confined to forward part of body.

dl Body with a mid-dorsal keel ; jaw smooth 12. LIMACIDAE

da No keel or an indistinct one ; jaw ribbed 13. ARIONIDAE

ca Mantle covers entire back 14. PHILOMYCIDAE

FAMILY 1. ONCHIDIIDAE.

Shell wanting; body ovoid, with no tentacles but with the eyes at
the tips of a pair of stalks; mantle entirely covers the back; respiratory,
anal, renal, and female genital pores at the hinder end of the body; male
pore below the right eye stalk : 3 genera and species, which live mostly in
shallow water along the seashore in warm countries, 2 on the Pacific coast.

ONCHIDELLA Gray. With the characters given above.

0. carpenter! Binney. Body oblong with rounded extremities and
sides, and gray in color; no jaw; 5 mm. long and 3 mm. broad: Puget
Sound to Gulf of California.

FAMILY 2. PUPILLIDAE.*

Small, often minute snails, with a more or less cylindrical or conical,
blunt, multispiral shell; aperture small, usually contracted by internal
teeth or lamellae; jaw smooth or finely striate, sometimes with acces-
sory plate; umbilicus open; ureter straight: cosmopolitan; over 1,000
species, which live under or in decaying wood or leaves, usually in
moist places; 50 American species.

Key to the genera of Pupillidae here described :

at Shells pupiform (Fig. 788).
&! Aperture without teeth, or with but 1 or 2.

G! Shell cylindrical 1. PUPILLA

ca Shell elongate and tapering 2. PUPOIDES

62 Aperture with teeth.
Cj Outer lip regularly rounded ; 4 tentacles.

di No tooth on columella 1. PUPILLA

d2 One or more teeth on columella 3. BIFIDARIA

c2 Outer lip indented above the middle ; 2 tentacles 4. VERTIGO

oa Shell heliciform (Fig. 772) 5. STEOBILOPS

1. PUPILLA Leach. Shell minute, with impressed sutures, horn-
color, and smooth; aperture with no teeth or with but 1 or 2 small
ones and with an expanded and reflected lip; whorls 5 to 9; posterior

Achatinella," by H. A. Pilsbry, Proc. Acad. Nat. Sci., Vol. 52, p. 561, 1900.
"Molluska of Michigan, Part 1, Terrestrial Pulmonata," by Bryant Walker, Rep.
Geol. Sur., Mich., for 1905, p. 431.

* See "A Partial Revision of the Pupae of the United States," by H. A. Pilsbry
and E. G. Vanatta, Proc. Acad. Nat. Sci., Phila., Vol. 52, p. 582, 1900.

516 MOLLUSCA

tentacles long; anterior tentacles very short: cosmopolitan; numerous
species, 6 American, mostly in the West.

P. muscorum (L.) (Fig. 788). Shell stout, cylindrical, with 6 or 7
whorls; aperture nearly circular, either without or with 1 or 2 teeth;
length 4 mm. ; breadth 1.5 mm. : North America ; circumpolar.

2. PTTPOIDES Pfeiffer. Shell rather slender and tapering, with 6 or
7 whorls, smooth and shining; aperture ovate, without teeth: in all
continents except Europe; 3 American species.

P. marginatus (Say) (P. fallax Say) (Fig. 789). Jaw strongly
arched; umbilicus deep; length 5 mm.; diameter 2 mm.: United States,
east of the Rocky Mountains.

3. BIFID ART A Sterki. Shell conical or ovate, smooth or finely
striate; aperture dentate with usually a large bifid parietal lamella, 2
lipfolds, and a basal tooth; additional teeth sometimes present: about
22 American species.

Key to the species of Bifidaria here described:

«! Aperture almost edentate B. CORTICARIA

oa Aperture with prominent teeth.

6± Aperture nearly closed by 4 or 5 large teeth B. ARMIFERA

Z>3 Aperture with 5 to 9 smaller teeth B. PENTODON

Fig. 788 Fig. 789 Fig. 790

iscorum (Morse). Fig. 789 — Pupoides
Fig. 790 — Bifidaria corticaria (Binney).

Fig. 788 — Pupilla muscorum (Morse). Fig. 789 — Pupoides marginatus (Binney).

• ' (Binn

B. corticaria (Say) (Fig. 790). Shell white, shining, cylindrical,
with an obtuse apex; whorls 5 to 6, convex; aperture with but 1 or 2
teeth on parietal wall, or none, and a very blunt tooth on the columellar
wall; length 2.5 mm.; diameter 1 mm.: eastern states, to the Mississippi.

B. armifera (Say) (Fig. 791). Shell cylindrical, with 6 to 7 whorls;
aperture with a wide rim and 4 to 6 teeth, the parietal lamellae large,
irregular, with 1 or 2 projecting points; columellar lamella thick and
situated deep in the aperture; lipfolds 2; length 4.5 mm.; diameter 2.2
mm. : from the Atlantic to the Rocky Mountains.

B. pentodon (Say). Shell conical, white, whorls 5, convex; aper-
ture with a broad rim and with 8 teeth, the parietal and inferior lip
lamella curved to the left; length 2 mm.; diameter 1 mm.: America.

4. VERTIGO Draparnaud. Shell ovate or conical, with 4 to 6 convex
whorls; apex obtuse; aperture with a narrow, white rim, the outer lip
of which is usually straightened or indented at its upper third; with

GASTROPODA

517

4 to 7 teeth; anterior tentacles absent: a circumboreal genus, with
about 36 American species.

Key to the species of Vertigo here described:

Oj But 1 parietal tooth V. VENTBICOSA

aa Two parietal teeth.

Z>! Shell over 2 rnm. long V. OVATA

6a Shell about 1 mm. long V. MILIUM

V. ovata Say (Fig. 792). Shell ovate, dark amber-colored, smooth,
and shiny; outer lip of aperture indented; 6 to 12 teeth, 2 or 3 parietal,
2 columellar, and 2 to 6 on the lip; length 2.2 mm.; diameter 1.5 mm.:
North America; the commonest species.

V. ventricosa (Morse). Shell ovate, smooth, and polished, with 4
whorls; lip of aperture with a deep indentation; teeth 5, 1 parietal, 2

Fig. 791

Fig. 792

Fig. 793

Fig. 791 — Bifldaria armifera (Binney). Fig. 792 — Vertigo orata (Morse).
Fig. 793 — Vertigo milium (Morse).

columellar, and 2 on the lip; length 1.7 mm.; diameter 1.1 mm.: north-
eastern and north-central America; California.

V. milium (Gould) (Fig. 793). Shell ovate and very minute; dark
amber in color; lip of aperture indented; teeth 6 to 8, 2 parietal, 2
columellar, 2 on lip, the upper one being large and sharply bent down-
wards at its inner end ; length 1.4 mm. ; diameter
.8 mm. : America, east of the Mississippi River

5. STROBILOPS Pilsbry. Shell more or less
helicif orm with 5 or 6 striated whorls ; parietal
wall with several entering revolving lamellae:
5 American species.

S. labyrinthica (Say) (Fig. 794). Shell with 6 whorls, 2.1 mm.
wide and 1.6 mm. high, with 3 parietal lamellae, each of which has
swellings at regular intervals: eastern and central states.

Fig. 704 — StrnWlops laby-
rinth ica ( Walker) .

FAMILY 3. COCHLICOPIDAE.

Shell elongate, slender, conical, without umbilicus; aperture eden-
tate, rounded, or lengthened; ureter straight: 200 species, cosmopolitan.

COCHLICOPA Ferussac. Shell smooth and glossy; jaw slightly
arched, without ribs and with a median projection : 2 American species.

518 MOLLUSCA

C. lubrica (0. F. Muller) (Fig. 795). Shell 6 mm. high, with 6
whorls, and yellowish in color: circumpolar; often common under dead
leaves or decaying bark.

FAMILY 4. VALLONIIDAE.

Shell minute, with a low depressed spiral, widely umbilicate, con-
sisting of 3 or 4 whorls, the last of which is large and cylindrical;
ureter straight: 1 genus.

VALLONIA Risso. Aperture edentate, round; peristome reflected
and white ; jaw with numerous slight transverse ribs : 9 American species.

Fig. 795 Fig. 796 Fig. 797

Fig. 795 — Cochlicopa lubrica (Binney). Fig. 796 — Vallonia jtulcliella (Sterki).
Fig. 797—VaUowacostata (Sterki).

V. pulchella (0. F. Muller) (Fig. 796). Height 1.3 mm.; diameter
2.6 mm.; shell thin, light colored, and transparent: circumpolar; north-
ern states; often very common, under sticks, stones, and logs and in
other dark, damp places.

V. costata (Mull.) (Fig. 797). Height 1.3 mm.; diameter 2.7 mm.;
shell with regularly recurring transverse ribs; color gray: circumpolar;
northern states.

FAMILY 5. SUCCINEIDAE.

Shell very thin, with a small spire and a large, often flaring aper-
ture; anterior tentacles very small or wanting; jaw with an accessory
quadrangular median piece : 6 genera, 3 American.

STJCCINEA Draparnaud. Shell fragile and transparent and not too
small to contain the body; tentacles short and thick; foot broad; ureter
reflexed: 200 species, on plants in wet places; 25 American species:

Key to the species of Succinea here described :

«! Aperture occupying the greater part of the shell.

&! Aperture wide and oblique S. OVALIS

fcj Aperture long, narrow, and straight S. RETUSA

aa Aperture round, occupying a little over half of the shell S. AVABA

S. ovalis Say (S. obliqua Say) (Fig. 798). Shell ovate, pale green
or yellowish and shining, and minutely striated, with 3 whorls; spire
small; aperture oblique and very large; length 28 mm.: eastern and cen-
tral America ; very common.

GASTROPODA

519

S. retusa Lea (S. ovalis Gould). Shell ovate, with 3 whorls, light
yellowish or grayish and shining and minutely striate ; spire short ; aper-
ture long and narrow ; length 19 mm. ; width 7 mm. : eastern and central
states.

S. avara Say (Fig. 799). Shell elongate,
with a long spire, yellowish, rosy, or greenish ;
whorls 3; suture very deep; length 11 mm.;
width 4.5 mm. : North America ; common ; often
under wet logs.

Fig. 798

Fig. 798 — Succinea ovalis
(Binney). Fig. 799 — Succi-
nea avara (Baker).

FAMILY 6. HELICIDAE.

Shell with a rather low conical spire and
consisting of 5 to 7 whorls; aperture either
simple or with teeth, and with a wide re-
flexed lip; teeth of radula bicuspid and tricuspid; ureter reflexed; foot
without marginal grooves : about 30 genera and several thousand species.

Key to the genera of Helicidae here described:

at Dart sac, genital mucous glands, and flagellum present (Fig. 800) . .1. HELIX
aa Dart sac, genital mucous glands, and flagellum absent (Fig. 801) .2. POLYGYRA

1. HELIX* L. Shell heliciform (Fig. 772) ; jaw with prominent
ribs; 1 or 2 dart sacs, genital mucous glands, and flagellum present
(Fig. 800), although these organs may be rudimentary: many hundred

species in the Palearctic re-
gion; poorly represented in
America.

H. aspersa 0. F. Muller
(Fig. 771). Shell yellowish
or grayish, with brown re-
volving bands of varying
widths; lowest whorl very
large; aperture large, round,
without teeth; height and di-
ameter 22 mm. : an European
species, which has been found
in Portland, Maine, Charles-
ton, S. C., and other places;
California.

H. pomatia L. French snail. Edible snail. Shell rather thin, 5
cm. long and wide, yellowish-brown in color, often with several broad
revolving bands; aperture without teeth; narrow, deep umbilicus pres-

Fig. 800 — Portion of the genital organs of
Helix (Kingsley). 1, genital pore; 2, penis;
3, flagellum ; 4, proximal portion of sperm duct ;
5, proximal portion of oviduct ; 6, proximal
portion of spermatheca ; 7, mucous glands ; 8,
dart sac.

* See "Land and Fresh Water Mollusks of Yucatan and Mexico," by H. A. Pilsbry,
Proc. Acad. Nat. Sci., Phila., 1891, p. 313.

520

MOLLUSCA

-.•2,

Fig. 801 — Genital organs of Polygyra
(from Walker). 1, genital pore; 2,
sperm duct ; 3, oviduct ; 4, albuminous
gland ; 5, hermaphroditic duct ; 6,
hermaphroditic gland; 7, retractor
muscle ; 8 spermatheca ; 9, penis.

ent : an European species, introduced into New Orleans and other places :
imported into New York for food.

H. hortensis (Mull.) (Fig. 802). Shell yellowish, usually striped
with several revolving dark bands; aperture without teeth; peristome

white; umbilicus closed; height 12
inm. : an European species, introduced
into eastern New England.

H. nemoralis L. Like the above,
with black peristome: an European
species found at Burlington, N. J., and
in Virginia in trees.

H. californiensis Lea. Shell vari-
able in shape and color, globose, thin,
and transparent, shining, pale yel-
lowish, with a narrow, brown, re-
volving band, paler at its edges;
height 15 mm.; diameter 19 mm.:
California.

2. POLYGYRA Say. Shell helici-
form (Fig. 722) ; aperture usually
dentate, 1 tooth being parietal and 2

on the lip, but they may be absent; jaw with about a dozen promi-
nent ribs; dart sac, genital mucous glands, and flagellum absent (Fig.
801); foot without marginal grooves: a North American genus with
125 species, which are most often found in moist and more or less open
woodlands.

Key to the species of Polygyra here described :

at Aperture tridentate.

6X Aperture distinctly ear-shaped P. ATJBIFORMIS

6a Aperture not ear-shaped.

G! Umbilicus open P. TEIDENTATA

ca Umbilicus closed.

dt Diameter exceeding 20 mm P. PALLIATA

dt Diameter less than 15 mm P. INFLECTA

a, Aperture unidentate.
&! Aperture broad and more or less circular.

Cj Umbilicus open P. THYROIDES

c, Umbilicus closed P. ALBOLABRIS

6, Aperture very narrow.

Ci Surface of shell hirsute P. HIRSUTA

ca Surface smooth P. MONODON

oa Aperture edentate.

&! Shell without spiral lines P. ALBOLABRIS

Z>a Shell with spiral lines.

G! Umbilicus open P. PROFUNDA

ca Umbilicus closed P. MULTILINEATA

GASTROPODA

521

P. auriformis (Bland) (Fig. 803). Shell white or yellowish, stri-
ated, with a very short spire, umbilicus open; aperture ear-shaped, con-
tracted by 3 prominent teeth; height 6 mm.; diameter 11.5 mm.: Texas
to Georgia; very common.

P. hirsuta (Say). Shell brownish and covered with rigid hairs;
aperture very narrow, being contracted by an elongated tooth on the
parietal wall ; umbilicus
closed; height 5 mm.; diame-
ter 9 mm.: New England to
Kansas, south to Virginia.

P. monodon (Rackett).

Fig. 802 Fig 803

Fig. 802 — Helix hortensis (Binney). Fig. 803—
Polygyra auriformis (Binney).

Shell yellowish, umbilicus open

or closed, aperture lunate,

with an elongate tooth on the

parietal wall ; peristome white, reflected ; height 6 mm. ; diameter 11 mm. :

eastern and central America; common, generally in groups of about a

dozen.

P. profunda (Say) (Fig. 804). Shell depressed, with a wide umbili-
cus, and with numerous narrow revolving dark lines; color brownish
or yellow; height 15 mm.; diameter 30 mm.: central states J abundant.
P. tridentata (Say). Shell with low, depressed, yellowish spire,
with 5V2 whorls and open umbilicus; aperture with 3 teeth; 8 mm. high;
16 mm. in diameter: eastern North America.

P. palliata (Say). Shell dark brown,
with 5 whorls; aperture with white peri-
stome and 3 teeth; umbilicus closed; height
10 mm.; diameter 21 mm.: eastern North
America.

P. inflecta (Say). Shell, brown in color,
striated, umbilicus closed; aperture con-
tracted with 2 acute teeth on the inner
margin of the peristome, and a long low
tooth on the parietal wall; height 6.6

mm.; diameter 12 mm.: southern and central states west of the
Alleghenies.

P. albolabris (Say) (Fig. 805). Shell yellowish-brown in color,
with 5 or 6 whorls; umbilicus closed; aperture without teeth or with a
slight one on the parietal wall; peristome flat, white, and very widely
reflected; height 24 mm.; diameter 30 mm.: usually very common in
eastern and central United States.

P. multilineata (Say). Shell yellowish-brown, striped with numer-
ous narrow revolving dark bands; aperture without teeth; peristome

Fig. 804

Fig. 805

Fig. 804 — Polygyra profunda
(Baker). Fig. 80o — Polygyra
albolabris (Baker).

522

MOLLUSCA

narrow; umbilicus closed; height 14 mm.; diameter 23 mm.: America
west of the Alleghenies and south of central Michigan.

P. thyroides (Say) (Fig. 806). Shell depressed, thin, yellowish-
brown; aperture with a prominent white tooth on parietal wall; umbili-
cus narrow and partially covered by the reflected peri-
stome; height 18 mm.; diameter 22 mm.: eastern and
central America.

FAMILY 7. ENDODONTIDAE.

Shell conical or depressed, ribbed or striated, usually
with brown markings, and with open umbilicus; lip thin
and sharp, usually without teeth: 4 American genera.
Key to the genera of Endodontidae here described:

ax Jaw composed of a single piece.

&! Spire raised, but low 1. PYBAMIDULA

6a Shell discoid 2. HELICODISCUS

az Jaw composed of numerous overlapping pieces; shell

heliciform (Fig. 772) 3. PUNCTUM

Fig. 806

thyroides
(Baker).

1. PYEAMIDULA Fitzinger. Shell with 5 or 6 whorls and a wide
umbilicus; aperture rounded and large, usually without teeth; foot with
marginal grooves which meet behind; dart sac, mucous genital glands,
and flagellum absent; jaw not ribbed, but striated: cosmopolitan; about
12 American species.

Key to the species of Pyramidula here described :

at Shell without prominent transverse ribs.
Z»j Shell color with markings.

Ci Shell with 2 or 3 revolving bands P. SOLITABIA

c2 Shell with broken, irregular transverse bands. P. ALTEBNATA

&2 Shell color plain P. PEBSPECTIVA

aa Shell with prominent transverse ribs P. ASTEBISCUS

P. solitaria (Say) (Fig. 807). Shell elevated, white
or reddish, striped with 2 or 3 broad revolving brown
bands; height 19 mm.; diameter 25 mm.: America, north
of the Ohio River; Oregon and Washington.

P. alternata (Say). Shell depressed, yellowish, with oblique and
broken red bands ; height 10 mm. ; diameter 21 mm. : eastern and central
America; abundant in decaying logs and other damp places; gregarious.

P. perspectiva (Say). Shell flattened, thin, brownish; aperture
small, often with a single small tooth; height 3 mm.; diameter 8 mm.:
eastern and central America, but not east of the Alleghenies north of
Maryland.

P. asteriscus (Morse). Shell very flat, with 25 or 30 prominent
transverse ribs on the whorls; height .5 mm.; diameter 1.5 mm.: New
England and Canada; California.

Fig. 807

Pyramidula

solitaria

(Baker).

GASTROPODA 523

2. HELICODISCUS Morse. Shell disc-shaped, with the spire flat, and
the umbilicus broad and shallow, the last whorl with 1 or more internal
teeth; jaw crescentic, with a median projection: 2 American species.

H. parallelus (Say) (H. lineatus Say) (Fig. 808). Height 1.5 mm.;
diameter 4 mm., with parallel, raised, revolving lines: eastern United
States, living under leaves, loose bark, etc.

3. PUNCTUM Morse. Shell depressed and discoidal, small or minute ;
aperature large, with a thin lip and without teeth; jaw composed of
16 to 19 separate quadrate plates: circumpolar; 6 American species.

P. pygmaeum (Draparnaud) (Fig. 809). Umbilicus open; shell
minute ; height 1 mm. ; diameter 1.5 mm. : eastern United States.

FAMILY 8. BULIMULIDAE.

Shell elongate, with a high conical spire; aperture elongate, eden-
tate; jaw arched with prominent ribs; radula with central tricuspid
and lateral bicuspid teeth ; ureter reflexed : over 1,000 species, principally
in tropical America.

Fig. 808 Fig. 809 Fig. 810

Fig. 808 — Helicodiscus parallelus (Binney). Fig. 809 — Punctum pygmceum (Binney).
Fig. 810 — Bulimulus dealbatus (Binney).

BTTLIMULUS Leach. With the characters of the family: about 6
species in the United States, all southern.

B. dealbatus (Say) (Fig. 810). Shell thin, white, with gray longi-
tudinal lines, 6 or 7 whorls; aperture oval, with an acute lip; 18 mm.
long; 12 mm. thick: southern states, north to North Carolina and Mis-
souri; common.

FAMILY 9. CIECINABIIDAE.

Shell either internal or external and heliciform, thin,
with a wide umbilicus, depressed, with 5 whorls; aperture
large, with a somewhat thickened lip ; jaw crescentic, stri-
ated, with a median projection; radula with long thorn-
like teeth, the animals being carnivorous; ureter reflexed:
12 American species, all on Pacific slope but one.

CIRCINARIA Beck. Shell external: several species.

C. concava (Say) (Fig. 811). Height 8 mm.; diameter 17 mm.;
color whitish: eastern and central states.

524 HOLLUSCA

C. Vancouver ensis Lea. Height 14 mm.; diameter 31 mm.; color
yellowish: Washington, Idaho, and northwards.

FAMILY 10. TESTACELLIDAE.

Shell variable in shape, animal long and slug-like; jaw absent;
radula with long thorn-like teeth, the animal being carnivorous; ureter
reflexed: about 12 genera.

1. TESTACELLA Cuvier. Shell very small and rudi-
mentary, and ear-shaped, and carried on the back near the
hinder end : 7 species, principally in western Mediterranean
countries.

T. haliotoidea (Ferussac). Length of shell 7 mm.;
breadth 4.5 mm.; body of animal 5 times as long: green-
houses in Philadelphia and other cities, where it feeds on
worms, snails, etc.

2. EUGLANDINA Ferussac. Shell tall and conical,
6 to 8 whorls; tentacle-like lip on each side

mouth : tropical America; 4 species in the southern
states.

E. rosea Fer. (E. truncata Gmelin) (Fig. 812). Shell 37 mm. long or
more and 13 mm. thick, and fluted with longitudinal ridges: South Caro-
lina to Texas; it leads a semi-aquatic life, feeding largely on snails.

FAMILY 11. ZONITIDAE.

Shell thin and delicate, usually depressed, often very small; usually
with umbilicus; jaw smooth or nearly so, with a median projection;
aperture large with a thin lip; foot with marginal grooves and caudal
mucous gland; ureter reflexed: cosmopolitan; 65 American species, which
live under dead leaves, rotting logs, and in other similar places.

Key to the genera of Zonitidae here described:

ax Dart sac and mucous genital glands absent.

6j Whorls 2 or 3 ; no umbilicus 2. VITBINA

6, Whorls 4 or more ; usually with umbilicus.
cx Spire depressed.
d^ Shell 15 mm. or more in diameter, smoky in appearance ... 1. OMPHALINA

<f a Shell small, glassy in appearance 3. VITREA

Cj Spire high 4. EUCONULUS

oa Dart sac and genital mucous glands present (Fig. 800).
&! Internal teeth or a calcareous deposit on floor of largest whorl.

6. GASTRODONTA
6, No internal teeth ; umbilicus wide 5. ZONITOIDES

1. OMPHALINA Rafmesque. Shell striated above, smooth below, with
umbilicus; last whorl dilated; aperture broad, with an acute lip: about
14 species, all North American.

GASTROPODA

525

Fig. 813

(23

Fig. 814

Fig. 813— Omphalina fuligi-
nosa (Baker). Fig. 814 — Vit-
rina limpida (Binney).

O. fuliginosa (Griffith) (Fig. 813). Shell depressed, thin, glossy,
and dark colored, with 41/*> whorls and with a deep umbilicus; height 13
mm.; diameter 26 mm.: eastern and central
states.

2. VITRINA Draparnaud. Shell small,
not entirely enclosing the animal, with a
low spire, thin and shining, and 2 to 3
whorls, the last large, with a large aperture
and a thin lip : cosmopolitan ; 100 species, 3
American, all northerly.

V. limpida Gould (Fig. 814). Height 3 mm.; diameter 6 mm.:
western Pennsylvania, and to the west and north of it.

3. VITEEA Fitzinger. Shell thin, smooth, and shining, depressed

with 4 to 6 whorls; animal black dorsally: 21 American
species.

V. hammonis (Strom) (Fig. 815). Shell with a nar-
row umbilicus, brownish in color; 2.5 mm. high and 5 mm.
wide: entire country, south to South Carolina; common;
Europe.

V. indentata (Say). Shell highly polished, without
umbilicus, but with umbilical region indented; 2.5 mm.
high and 5 mm. wide: entire country.

4. EUCONTTLTJS Reinhardt. Shell with 'a very narrow umbilicus
or with none, with rather high spire of 5 or 6 whorls : 3 American species.

E. fulvus (0. F. Miiller) (Fig. 816). Shell smooth and shining,
light yellowish in color; 3 mm. high and 4 mm. in diame-
ter; color of animal black: circumpolar; entire country;
very common.

5. ZONITOIDES Lehmann. Shell depressed, with wide
umbilicus, smooth or ribbed, shining; aperture large,
without teeth; long dart sac present: 15 American
species.

Key to the species of Zonitoides here described:

Oj Surface of shell smooth.

bi Diameter 7.5 mm Z. NITIDA

6, Diameter 5 mm Z. ARBOBEA

a, Surface striated or ribbed ; shell minute.

&! Surface striated Z. MINUSCULA

6a Surface folded and reticulated. Z. MILIUM

Z. nitida (0. F. Muller). Shell elevated, with polished, yellowish
surface and 5 whorls; 3.6 mm. high and 7.5 mm. in diameter; animal
black: northern states and Canada; common on the banks of streams;
Europe.

Fig. 816
Euconulus

fulvus
(Walker).

526 MOLLUSCA

Z. arborea (Say). Shell depressed, amber-colored, polished, with 5
whorls; deep and narrow umbilicus; 2.75 mm. high and 5 mm. in diam-
eter; head and neck black, rest of body white: entire country, the com-
monest species, living gregariously under bark, leaves, etc.

Z. minuscula (Binney). Shell depressed, with 4 whorls, with a very
wide umbilicus; aperture circular, with an acute lip; height 1 mm.;
diameter 2.5 mm.: entire United States; common.

Z. milium (Morse). Shell depressed, with a broad umbilicus, stri-
ated, with 3 whorls; height .5 mm.; diameter 1.5 mm.: entire United
States; common.

6. GASTRODONTA Albers. Shell usually with an umbilicus, with
5 to 7 whorls and yellowish in color; aperture lunate, with an acute lip,
either with internal teeth not reaching the margin or thickened by an
internal calcareous deposit ; animal black, with a long dart
sac and mucous genital glands: 19 American species.

G. suppressa (Say). Shell depressed, with a large
whorl, thin; aperture rather large; lip thickened by a

Fig. 817 white deposit within it and with 1 or 2 parallel ridges ;

Gastrodonta . • ,. - -,. ,-, * .,.

Ugera height 5 mm.; diameter 8 mm.; umbilicus small or

rudimentary: eastern and central states.

Cr. ligera (Say) (Fig. 817). Shell with a rather high spire; aper-
ture thickened within ; height 10 mm. ; diameter 15 mm. : central states.

FAMILY 12. LIMACIDAE.

Slugs. No external shell present, but a rudimentary shell in form
of a thin calcareous plate in the mantle; body elongate and tapering;
mantle not extending back of the middle of the body; jaw without ribs
and with a median projection; ureter reflexed: about 20 genera and
several hundred species, which live in gardens and woods, in moist places,
and are nocturnal in their habits; 6 American species.

Key to the genera of Limacidae here described:

»! Large slugs, with spots 1. LIMAX

a, Small slugs, unspotted 2. AGBIOLIMAX

1. LIMAX L. Body tapering and keeled behind, terminating with a
point; jaw with blunt ends: cosmopolitan.
Key to the species of Limax here described :

d! Spots white L. FLAVUS

a, Spots and blotches black L. MAXIMUS

L. flavns L. Color yellowish or brownish, with oblong uncolored
spots; body covered with long, narrow tubercles; head bluish; length 85

GASTROPODA

527

Fig. 818 — Limax maximus (Baker). 1, mantle; 2,
respiratory pore ; 3, anterior tentacles ; 4, posterior ten-
tacles ; 5, eye ; 6, genital pore.

mm. or more: an European species present locally in many places in the
eastern states.

L. maximus L. (Fig. 818). Color gray, with alternate longitudinal
rows of spots and

stripes of black, re- - '

placed by irregular
blotches on the man-
tle; dirty white be-
low ; body covered
with coarse, e 1 o n-
gated tubercles;

length 16 cm. : an European species present locally in many places in the
eastern states; California.

2. AGRIOLIMAX Morch. Body keeled behind and unspotted; jaw
with blunt ends : animals live under stones and decaying wood and feed
on leaves, etc.; they can suspend themselves by
threads of mucous from bushes and trees.

A. campestris (Binney) (Fig. 819). Color uni-
formly grayish or amber, often blackish; upper
surface covered with prominent tubercles, not flat-
tened ; mantle oval ; mucous watery ; length 25 mm. :
common in eastern and central America, under logs,
damp leaves, etc. ; California.

A. agrestis (L.). Upper surface covered with flat, gray, or brown
tubercles, separated by darker-colored anastomosing grooves; mantle
pore bordered with white ; mucous milky ; length 25 to 50 mm. : eastern
America; California; an European species locally present in many
places.

FAMILY 13. ABIONIDAE.*

Slugs. No external shell, but the small shield-like mantle usually
encloses a calcareous rudiment of one; body elongate, limaciform; jaw
with prominent ribs; foot with marginal furrows; ureter reflexed: 4
genera; about 15 American species, mostly on the Pacific slope.

1. ARION Ferussac. Body ending obtusely behind; back covered
with elongated tuberosities arranged in rows, and not keeled; mantle
oval and covered with granulations containing calcareous particles,
which represent the shell; mantle pore anterior: 25 species, all in the
Old World.

A. hortensis Fer. Color gray or yellowish or black ; length 5 cm. : an
European species, which occurs locally in New England and other places.

Fig. 819 — Agrioli-
max campestris (Bin-
ney). 1, mantle; 2,
posterior tentacles.

* See "Revision of North American Slugs," by H. A. Pilsbry and E. G. Vanatta,
Proc. A cad. Nat. Sci., Phila., 1896, p. 339; also 1898, p. 219.

528 MOLLUSCA

2. ARIOLIMAX Morch. Body tapering and somewhat keeled: 6
species, all on the Pacific slope.

A. columbianus (Gould). Color greenish-yellow, sometimes blotched
with darker patches; length 15 cm.: Washington, Oregon, and Califor-
nia, in damp forests.

A. niger Cooper. Color nearly black, sometimes gray ; length 5 cm. :
central California.

FAMILY 14. PHILOMYCIDAE.

. Slugs. No internal or external shell; body limaciform, with the
mantle covering the entire back and tapering behind; no caudal mucous
pore ; ureter reflexed : 2 genera ; 5 American species.

1. PHILOMYCTTS Ferussac. Jaw
smooth, strongly arched and with a
median projection ; respiratory pore

near the head; foot with marginal
Fig. 820 — Philomychus carolinensis (Bin-

ney). 1, mantle ; 2, respiratory pore. grooveb.

P. caroliniensis (Bosc) (Fig.

820). Color whitish with dark spots and blotches; length 7 cm.: eastern
and central states, in forests in trees, under bark, or in rotten wood, being
partial to basswood.

2. PALLIFERA Morse. Jaw with stout ribs on its anterior surface,
and without a median projection.

P. dorsalis (Binney). Color ashy, with an interrupted mid-dorsal
line; jaw with 9 ribs; length 18 mm.: northeastern and central states.

P. hemphilli (Binney). Color black; jaw with 4 or 5 ribs: central
states; rare.

ORDER 3. PROSOBEANCHIATA. (STREPTONEURA.)

Mostly marine snails, in which the ctenidium lies in the mantle cavity
at the forward end of the body (Fig. 828,1) and in front of the heart.
In a few primitive forms (Zygobranchiata) a pair of ctenidia is present.
The Helicinidae and Proserpinidae are without gills and the ctenidium is
replaced by a lung, the animals beng terrestrial. Near the ctenidium
in the inner surface of the mantle is the hypobranchial gland, which,
in Murex and Purpura, becomes the purple gland; its function is un-
known. With rare exceptions the animal is provided with a shell, which
is often of large size and is sometimes very thick and heavy, and in
many forms very beautifully marked and colored. The operculum is
almost invariably present, and is either calcareous or horny, and either
spiral or annular.

GASTROPODA

529

The foot forms a broad sole, except in the Heteropoda: in a few
forms it can envelop the shell (Natica). The head, which often projects
snout-like forwards, bears a single pair of non-retractile tentacles and a
pair of eyes, which are either at the base of or on the tentacles or at the
tips of stalks of their own. The higher prosobranchs are distinguished by
the possession of a proboscis, which can often be thrust out far in advance
of the animal, and also a siphon, which is formed by a prolongation of the
anterior margin of the mantle, and in many snails lies in a characteristic
prolongation of the shell called the anterior or siphonal canal (Fig. 872, 1).
Paired jaws are present in the non-carnivorous forms, the carnivorous
ones being destitute of jaws. The radula varies much among the different
groups and is wanting in the Gymnoglossa.

The nervous system is strep toneurous, the pleurovisceral connectives
crossing each other. The sexes are separate, the male being usually dis-
tinguished by a slenderer shell. The eggs are laid usually in capsules
(Fig. 879), which vary much among the various forms, and are often
attached to rocks or other objects. Littorina deposits its eggs in 'a jelly.
The fresh-water Viviparidae bear their young alive.

The Prosobranchiata include about 27,500 living species, mostly marine,
which are grouped under two suborders.

Key to the suborders of Prosobranchiata:
at Gill bipectinate (Fig. 821, B) or absent, shell without siphonal canal

(Fig. 872, 1) 1. SCUTIBBANCHIATA

oa Gill monopectinate (Fig. 821, C) 2. PECTINIBBANCHIATA

SUBORDER 1. SCUTIBRANCHIATA. (ASPIDOBRANCHIATA; DIOTOCARDIA.)

Snails with a primitive
structure, a pair of ctenidia
being present in the Zygo-
branchiata, and in all others
the bipectinate ctenidia,
where present, projecting
freely anteriorly (Fig.
821, B) ; 2 auricles and 2 kid-
neys generally present, the
gonad opening to the outside
through the right kidney (except in the Neritidae) ; proboscis, siphonal
canal, and penis absent: 17 families, grouped in 2 divisions, inhabiting
the sea, fresh water, and the land.

Key to the divisions of Scutibranchiata:

di Shell conical and not spiral, and without a slit or hole 1. DOCOGLOSSA

aa Shell mostly spiral, but when not so with slits or holes, . . .2. RHIPIDOGLOSSA.

Fig. 821 — Prosobranch gills. A, paired; B,
bipectinate, and C, monopectinate gills (Lang).
1, branchial vein; 2, auricle; 3, ventricle; 4,
aorta.

530 MOLLUSCA

DIVISION 1. DOCOGLOSSA.

Limpets. Shell conical and not spiral; 2 osphradia; 1 auricle; 1
ctenidium or none; mantle margin often fringed (Patella)', jaw median
and unpaired; no operculum; radula very long, with but few hooked
teeth in each transverse row: 3 families, with 1,500 species, all marine
and occurring mostly in shallow water.

FAMILY ACM^IDAE.

Ctenidium present, projecting from the left to the right; apex of
shell usually inclined anteriorly: 1 species on the Atlantic and several
on the Pacific coast.

ACMJEA Eschscholtz. Shell solid and not iridescent within; ten-
tacles rather long and cylindrical; anus on the right; lips frilled and
elongated at the lower anterior corners; radula with 2
centrals; mantle margin not fringed: about 40 species.

A. testudinalis (L.). Common limpet (Fig. 822). Shell
depressed, smooth, gray or greenish in color, with dark
brown stripes radiating from the apex; inner surface
whitish, with a large brown spot; length 35 mm.; width
25 mm. ; height 9 mm. : circumpolar, south to Long Island
Sound and to Sitka ; common north of Cape Cod on rocks
in shallow water; a smaller, narrow, spotted variety
(A. alvea Conrad) is attached to eel grass; Europe.
A. patina Eschs. Shell 53 mm. long, 46 mm. wide, and 18 mm.
high; surface with radiating striations, grayish; inside white, with a
large, brown central area: entire Pacific coast; the commonest Cali-
fornian limpet.

DIVISION 2. RHIPIDOGLOSSA.

Shell usually spiral, the spire being in most cases low and little coiled ;
jaw paired; radula long; teeth, 1 central, 3 to 9 laterals, and very many
crowded marginals; 1 or 2 ctenidia; 2 auricles; 2 kidneys: 14 families,
in the sea, fresh water, and on the land, grouped in 2 subdivisions.

Key to the subdivisions of Ehipidoglossa:

Ci Shell and mantle with slits or holes ; 2 ctenidia 1. ZYGOBRANCHIATA

a, Shell without slits or holes ; 1 ctenidium 2. AZYGOBKANCHIATA

SUBDIVISION 1. ZYGOBEANCHIATA.

Shell and mantle with a marginal or an apical slit, or with marginal
holes; 2 ctenidia (Fig. 821, A) : 3 families, all marine.
Key to the families of Zygobranchiata described :

a± Shell patelliform (like Fig. 822) 1. FISSURELLIDAE

a. Shell spiral and flat ; aperture very wide 2. HALIOTIDAB

GASTROPODA

531

Fig. 823

Fissurella

barbadensis

(Rogers).

FAMILY 1. FISSUEELLIBAE.

Keyhole limpets. Shell non-spiral, conical; either anterior margin
notched or apex perforated; 2 symmetrical ctenidia; foot very large,
with an epipodial ridge on each side, which bears a series of cirri; no
operculum: several hundred species.

FISSTJRELLA Bruguiere. Apex of shell perforated;
shell wholly external, capable of containing the whole
animal : 125 species, mostly in warm waters.

F. barbadensis Gmelin (Fig. 823). Shell oval, per-
foration almost circular ; surface with radiating ribs, of
which about 11 are larger than the others ; color grayish
inside, with alternately green and white concentric rings ;
margin crenulated; length 37 mm.; width 24 mm.; height 9.5 mm.:
Florida, Bermuda, and West Indies; common.

F. volcano Reese. Shell oval; orifice a little in front of the middle
and oblong; color grayish, with 13 to 16 radiating purplish rays; length
25 mm.; width 17 mm.; height 10 mm.: Santa Cruz, California, and
southwards.

FAMILY 2. HALIOTIDAE.

Ear shells. Shell ear-shaped, the spire being flat and the aperture
enormously expanded, and perforated with a spiral series of holes near
the left margin; no operculum; eyes on stalks near the outer base of

the tentacles ; foot very large,
surrounded by fringed and
tentacled epipodia, which
project beyond the edge of
the shell and through the
holes; right gill smaller than
the left: 1 genus and about
100 species; the animals are
eaten in many places, and
the shells are much sought
after on account of their
beauty and for use in the
manufacture of buttons and
buckles and for inlaying.

HALIOTIS L. Abalones. With the characters of the family: Pa-
cific and Indian oceans and Europe; about 5 species on the Pacific
coast, living in shallow water. There is large export trade in the shells
and flesh of these animals, the latter being dried and sent to Japan and
China, the shells to Europe.

Fig. 824 — Haliotcs fulgcns (Rogers).

532 MOLLUSCA

H. rufescens Swainson. Red Abalone. Shell large and thick, 23
cm. long, 18 cm. wide, brick red in color outside and pinkish or green-
ish inside; 3 or 4 perforations: California, south of Cape Mendocino;
common.

H. fulgens Philippi. Green Abalone (Fig. 824). Shell thin, 15
cm. long, iridescent green in color; about 6 perforations: California,
south of Monterey.

H. cracherodi Leach. Black Abalone. Shell 12 cm. long, 10 cm.
wide, with 8 perforations, black outside: common south of the Farallone
Islands.

SUBDIVISION 2. AZYGOBEANCHIATA.

But 1 ctenidium (Fig. 821) ; shell usually with an elevated spire :
marine, fresh-water, and terrestrial; 11 families.

Key to the families of Azygdbranchiata here described:

GJ Animals marine.
&! Operculum horny ; shell conical ........................... 1. TEOCHIDAE

6, Operculum calcareous.
G! Spire not very small ................................... 2. TURBINIDAE

c. Spire very small ............ ............................ 3. NEBITIDAE

a, Animals terrestrial or in fresh water.
&! Spire very small ........................................ 3. NEBITIDAE

63 Spire not very small ................................... 4. HELICINIDAE

FAMILY 1. TROCHIDAE.

Shell usually conical, multispiral, with a flattened base, pearly
inside; operculum horny, multispiral; snout short; eyes on stalks at
outer base of the long tentacles, and fringed lobes present on the head
and foot: about 20 genera and over 1,000 species, all marine.

Key to the genera of Trochidae here described:

at Shell pyramidal.
&! Umbilical indentation present ............. 1. TBOCHUS

62 Without such indentation ............. 2. CALLIOSTOMA

aa Shell conical or globose .................. 3. MABGABITA

1. TROCHUS L. Shell pyramidal, with a flat base
and flattened whorls; aperture small, oblique, pearly,
with a thin outer lip; umbilicus indented: 250 species,
cosmopolitan, many with beautiful shells.

T. niloticus L. Shell 7.5 cm. long ; 9 cm. wide ; thick, smooth, white,
with brownish markings: Indian Ocean; often used as ornaments.

2. CALLIOSTOMA Swainson. Shell pyramidal, with a flat base, with-
out umbilicus; interior pearly: 28 species.

GASTROPODA

533

C. annulatum Martin (Fig. 825). Shell 30 nun. long and wide, thin,
light brown in color, with purple sutures : California.

3. MARGARITA Leach. Shell small, thin, conical or globose, with
open umbilicus ; whorls rounded and smooth : 24 species, in colder waters.

Key to the species of Margarita here described :

0! Shell solid, with 2 or 3 revolving ridges M. OBSCURA

cra Shell thin.

&! Shell with regular spiral lines M. UNDULATA

6a Shell yellowish in color M. HELICINA

M. obscura Couthouy (Fig. 826). Shell small, with a low, conical
spire and brownish in color; whorls 5, with 2 or 3 revolving ridges; these
with the coarse lines of growth give the shell an indented
appearance; length 10 mm.; diameter 12 mm.: Long
Island Sound to Labrador, in rather deep water towards
the south, but in shallow water towards the north;
common.

M. undulata (Sowerby). Shell thin, conical, brown-
ish or red in color, but lusterless ; whorls 6, with short wrinkles near the
suture, and with numerous elevated spiral lines at regular intervals;
length 7.5 mm. ; diameter 10 mm. : Cape Cod to the Arctic Ocean, from
low-water mark to deep water; Europe; common.

M. helicina (Fabricius). Shell small,
thin, light yellowish or pinkish in color, very
bright and polished ; whorls 4 or 5, very con-
vex; aperture large and circular; length 5
mm.; diameter 7.5 mm.: circumpolar, south
to Cape Cod and Vancouver; in deep water,
but often thrown up on beaches.

Fig. 826
Margarita 06-
scura (Try on).

FAMILY 2. TUEBINIDAE.

Shell large, spiral, conical, with a large
lower whorl and aperture; operculum cal-
careous and spiral: 100 species, mostly
tropical; about 8 species on the Pacific
coast.

1. TURBO L. Shell turbinate, with
rounded whorls ; aperture round : 76 species.

T. marmoratus L. (Fig. 827). Green snail. Shell 11 cm. long and
12 cm. wide; bright green, pearly inside; lip expanded, forming on the
columella a wide extension: Indian Ocean; used extensively as an orna-
ment and in the manufactures.

Fig. 827 — Turbo marmoratus
(Rogers).

534 MOLLUSCA

FAMILY 3. NERITIDAE.

Shell thick, semi-globose, with a small spire and a very large lower
whorl and aperture; operculum calcareous; cavity simple in consequence
of the absorption of the internal portions of the whorls; animal with a
broad, short snout; tentacles slender; eyes stalked; epipodium not fringed:
many hundred species, mostly marine, a few in fresh water and terrestrial.

NERITA L. Shell smooth or spirally ridged ; outer lip thick, usually
with teeth within : over 200 species, which live on rocks, feeding on algae.

N. fulgurans Gmelin. Shell with spiral ridges, black or gray in
color; aperture white, with prominent teeth; 18 mm. long; 30 mm. wide:
West Indies; California.

FAMILY 4. HELICINIDAE.

Shell conical or depressed, heliciform, with a single cavity due to
the absorption of the inner portions of the whorls; columella generally
with a thick callus, which covers the umbilicus; lip thick; operculum
oval or triangular; tentacles slender, with eyes at their base; ctenidia
absent, the mantle cavity being transformed into a lung: over 500
species, all terrestrial, chiefly in warm countries; about 4 species in the
southern states (70 species in Cuba).

HELICINA Lamarck. With the characters of the family: about 350
species in tropical America and the Pacific islands.

H. orbiculata Say. Shell yellowish in color, sometimes spotted,
with 5 whorls; 6 mm. high; 9 mm. in diameter: southern states, south
of Tennessee.

SUBORDER 2. PECTINIBRANCHIATA. (MONOTOCARDIA;

CTENOBRANCHIATA. )

But one auricle, kidney, osphradium, and ctenidium present, the cteni-
dium being monopectinate or feathered on but one side (Fig. 821, C) and
attached to the mantle its whole length (except in Janthina and Valvata) ;
proboscis, siphon, anterior or siphonal canal, and penis usually present;
gonad never opens into the kidney but has a separate duct : over 50 fami-
lies, grouped in 5 divisions and comprising most of the prosobranchs.
Key to the divisions of Pectinibrancliiata:

a± Radula short and wide, with numerous lateral and usually no central

teeth ; shell without siphonal canal 1. PTENOGLOSSA

aa Radula long and narrow, or wanting ; siphonal canal either present or

absent.
&! Radula with 7 teeth in each transverse row (Fig. 830) ; canal present

or not ; the majority of species 2. T^ENIOGLOSSA

62 Radula and jaw wanting; shell elongate, without canal... 3. GYMNOGLOSSA
Z>3 Radula with 3 teeth in each row (Fig. 870) ; shell thick, conical, with

canal 4. RACHIGLOSSA

54 Radula with 1 or 3 teeth in each row ; shell with an elongate aperture

and a canal 5. TOXOGLOSSA

GASTEOPODA

535

DIVISION 1. PTENOGLOSSA.

Shell conical or discoid, with a small, simple aperture; no siphonal
canal; radula with or without central tooth, but with numerous small
laterals: 3 families, all marine.

Key to the families of Ptenoglossa here described :

a^ Animal pelagic 1. JANTHINIDAE

a. Animals littoral ,2. SCALABIIDAE

FAMILY 1. JANTHINIDAE.

Shell thin and transparent, heliciform; 2 free ctenidia; foot small,
secreting a long vesicular float, which supports the animal at the surface
of the water, and to which the eggs are attached ; when handled, the animal
exudes a violet fluid: 12 species, in
warm waters, pelagic, gregarious,
feeding largely on jellyfish.

JANTHINA Lamarck. With the Vmm3 *

characters of the family: about 4
species off the Atlantic and 1 off
the Pacific coast. 3' foot ; 4' floa* > 5' ^gs'

J. fragilis Lam. (Fig. 828). Shell 20 mm. high; diameter 25 mm.;
color violet: tropical and pelagic, sometimes thrown up on the shores of
New England.

FAMILY 2. SCALAEIIDAE.

2, lateral ; 3, marginals.

Spiral staircases. Wentletraps.
Shell an elongated cone, white, with
many very convex whorls, which are
crossed by elevated ribs; operculum
horny ; a short siphon present ; the
animal exudes a purple fluid : about 4
genera and 200 species.

SCALARIA Lamarck. With the
characters of the family: numerous
species on the Atlantic coast, mostly in deep water and towards the south.
S. grcenlandica Perry. Shell rather long and tapering, 25 mm. long
and 9 mm. thick; whorls 10; ribs white, on a whitish or brown surface,
which has 6 or 8 revolving ridges : Cape Cod to the Arctic Ocean, in 10
to 100 fathoms; often common; Europe.

S. lineata Say (Fig. 829) . Shell long and tapering; 12 mm. long and 5

mm. thick; whorls 11: Cape Cod to Florida; common towards the south.

S. angulata Say. Shell 20 mm. long, 8 mm. wide; whorls 6 to 11,

touching one another only by the ribs: Long Island Sound to Texas,

common towards the south.

536 MOLLUSCA

DIVISION 2. T-ffiNIOGLOSSA.

Shell very variable in shape, with or without siphonal canal;
radula (Fig. 830) long and narrow, with 1 central, on each side of
which are 1 lateral and 2 marginal teeth, making 7 in each row : about 50
families, grouped in 2 subdivisions, including most prosobranchs.

Key to the subdivisions of Tcenioglossa:

Oi Foot with a broad sole 1. PLATYPODA

c, Foot fin-shaped ; animals pelagic 2. HETEEOPODA

SUBDIVISION 1. PLATYPODA.

Shell well developed ; foot with a broad sole, with which the animals
creep: 48 families, marine and in fresh water.

Key to the families of Platypoda here described :

av Aperture rounded, without siphonal canal (Fig. 831, 2).
&! Animals marine.

G! Shell regularly coiled or much flattened.

dl Shell not long and slender, but more or less globose or flattened.
Ci Shell conical and with a distinct spire (Fig. 772,3).
/! Umbilicus open (Fig. 831, 1) or more or less closed by a large callus.

1. NATICIDAE

/a Umbilicus closed 3. LITTOBINIDAE

e, Shell either not spiral or much flattened.

/! Spiral either absent or very inconspicuous 2. CAPULIDAE

/, Shell spiral, but discoid 6. SKENEIDAE

d, Shell elongate with a high spire.

6j Shell minute, less than 5 mm. long, with 5 or 6 whorls 4. RISSOIDAR

e, Shell very long, with about 10 whorls 12. TUERITELLIDA.E

c, Shell with a very irregular spiral 13. VERMETTDAE

6, Animals in fresh water.
Ci Shell usually minute, less than 5 mm. long, and always less than 10 mm.

dv Shell usually elongate and conical 5. HYDROBIIDAE

d, Shell usually flattened and discoid 8. VALVATIDAE

c, Shell not small, usually much more than 12 mm. long; heliciform
(Fig. 772).

di Snout simple ; tentacles short 7. VIVIPABIDAE

d, Snout divided into 2 long tentacular lobes ; tentacles long.

9. AMPULLABIIDAE

o, Aperture elongate, with siphonal canal (Fig. 872,1).
&! Canal short (Fig. 854), sometimes consisting only of the narrowed lower
edge of the aperture.

C! Surface ridged or tuberculated 10. CEBITHIIDAE

c, Surface usually smooth , . . 11. PLEUBOCEBIDAE

&, Canal long; aperture usually long and narrow (Fig. 859).
cx Spire low or hidden ; aperture nearly as long as the shell.

dl Spire almost or entirely hidden 15. CYPB^IDAE

dt Spire free and raised.
ex Shell thick, with thick reflexed lips.

A Outer lip with a notch near the lower end 14. STBOMBIDAE

/, Outer lip without a notch 17. CASSIDIDAE

ea Shell thin, with a thin lip 16. DOLIIDAE

c, Spire high ; aperture not half as long as shell 18. TRITONIDAE

GASTROPODA 537

FAMILY 1. NATICIDAE.

Shell usually globose or flattened, with a short spire; aperture round
or lunar; lip sharp; umbilicus open, or closed by a callus; operculum
usually corneous; foot very large and capable of being swollen by the
taking in of sea water into open spaces and reflected back over the shell
so as almost to cover it; tentacles small, lanceolate, wide apart, united
by a veil; eggs deposited in a "sand collar," a thin collar-shaped lamella
formed by agglutinating grains of sand together by means of mucous:
several hundred species.

Key to the genera of Natiddae here described :

ttj Shell globose 1. NATICA

aa Shell flattened with a very large aperture.

6t Shell ear-shaped 2. SIGABETUS

5a Shell trumpet-shaped 3. VELUTINA

1. NATICA Lamarck. Shell smooth and regular, gray or brownish
in color, with about 5 whorls; eyes wanting; umbilicus usually more or
less closed by a large callus: over 200 species; predacious animals, liv-
ing in the sand, where they burrow after bivalves; they envelop their
prey in the foot and penetrate its shell, drilling a hole with the radula;
they also devour dead fish; about 20 species on the Atlantic coast.

Key to the species of Natica here described :
G! Shell over 25 mm. long.

&! Umbilicus wide and deep N. HERDS

6, Umbilicus nearly closed by a brown callus N. DUPLICATA

a. Shell 15 mm. or less long.

&! Umbilicus wide and deep N. IMMACULATA

6a Umbilicus more or less covered by a white callus.

Ci Shell 8 mm. or less long N. PUSILLA

ca Shell over 10 mm. long.

di Shell with minute revolving lines N. GROZNLANDICA

da Shell without revolving lines N. CLAUSA

N. (Polynices Montfort) heros Say (Fig.
831). Shell large and moderately thick; whorls
5, convex; umbilicus large and deep; length 9
cm.; diameter 8 cm.; shell ash color, streaked
with chestnut: Virginia to Labrador; from low-
water mark to 238 fathoms; common.

N. (Polynices Montfort) duplicata Say. Shell
solid, whorls 5, flattened above; spire low; color
ashy gray, tending towards brown on the upper
side, chestnut brown within; callus very large,

chestnut brown in color, almost filling the umbilicus; length and
diameter 5^2 cm.: Massachusetts Bay to Mexico; common in shallow
water.

538 MOLLUSCA

N. pusilla Say (Fig. 832). Shell thin and small, often streaked
with brown; callus white, and pressed laterally into the umbilicus, which
is nearly closed; length 6 mm.; diameter 5 mm.: Massachusetts to west
Florida; common in shallow water.

N. (Polynices Montfort) immaculata Totten. Shell
solid and small; umbilicus rounded and deep, but little
covered by the small callus; color yellowish, and white

Fig. 832 beneath ; length 7 mm. ; diameter 5.5 mm. : Long Island

Natica pusilla ~ ,. _ ._ „ „,. _ ."' ' V n

(Verriii). Sound to the Gull or St. Lawrence, in shallow water;

often common.

N. groenlandica Holier. Shell small, smooth, glossy, bluish-white,
with minute revolving lines; 12 mm. long; 11 mm. in diameter; callus
white, nearly filling the umbilicus, leaving only a narrow, curved open-
ing: Cape Cod, northwards.

N. clausa Broderip. Shell small, whitish or brownish, without
revolving lines; 15 mm. long; 13 mm. in diameter; callus white, com-
pletely filling the umbilicus; operculum calcareous: circumpolar, south
to Cape Cod and Vancouver; common.

2. SIGARETTJS Lamarck. Shell flat and ear-shaped, with a minute
spire and an enormously expanded aperture; mantle large, partly
or entirely covering the shell; operculum minute, horny; propodium
enormously developed, used for

burrowing : 100 species, 3 on the
Atlantic coast.

S. perspectivus Say (Fig.
833 ) . Shell oval, flattened, white,
smooth, and polished; 37 mm.
long ; 30 mm. wide : New Jersey

to Florida; common in shallow "VftGS^^
water.

3. VELUTINA Blainville. Shell small, thin, covered with a velvety
periostraeum ; spire minute; lower whorl large, with a circular aperture;
no operculum: 2 species, on the Atlantic coast.

V. Isevigata (L.) (V. haliotoidea Fabricius) (Fig. 834). Shell very
thin and fragile, transparent, pinkish; whorls 3; length 12 mm.; diam-
eter 10 mm. : Cape Cod, northwards.

FAMILY 2. CAPULIDAE.

Shell conical, flat, or boat-shaped, with scarcely any spiral, or
none at all; interior with a shelf, variously formed, to which the
adductor muscles are attached; no operculum; head distinct, with a

GASTEOPODA

539

lengthened snout; the animal adheres by means of the broad foot to
stories and shells, arid does not move about: 7 genera and 160 species.
Key to the genera of Capulidae here described:

«! Shell conical ; partition cup-shaped 1. CBUCIBULUM

«2 Shell with a slight spiral; partition more or less horizontal. . . .2. CBEPIDULA

1. CRUCIBULTTM Schumacher. Shell, conical and not
spiral, with the apex directed posteriorly; shelf more or
less cup-shaped, attached to the inner wall near the apex,
on one side: cosmopolitan.

C, striatum (Say) (Fig. 835). Cup-and-saucer limpet.
Shell solid, with numerous elevated radiating lines; aper-
ture circular; white or yellowish in color; 12 mm. in
height and /20 mm. in diameter : Florida to Bay of Fundy ;
in 2 to 189 fathoms; common in shallow water towards
the north.

2. CREPIDTTLA* Lamarck. Shell oval, boat-shaped or
inconspicuous spire at the hinder end; shelf an internal
in the hinder half of the shell: 50 species, in all the
attached to shells, seaweed, etc.

Key to the species of Crepidula here

aT Shell convex.

&! Shell up to 45 mm. long ; shelf white. . . .

&2 Shell 12 mm. long or less ; shelf brown. . .
a2 Shell flat

Fig. 835

Crucibulum

striatum

(Verrill).

flat, with the
regular plate
warmer seas;

described :

.C. FORNICATA
. . C. CONVEXA
. ...C» PLANA

Fig. 836—CrepiO-

ulum fornicata

(Verrill).

C. fornicata (L.) (Fig. 836). Shell convex, with
one side more curved than the other; color whitish or
brownish; shelf concave, white; length 45 mm.; width
33 mm. ; height 15 mm. : Nova Scotia to South America,
in shallow water, very abundant ; Europe.

C. convexa Say. Shell very convex, the short side being nearly
vertical; color whitish or brownish; shelf deep-seated, convex, brown
in color, with a white edge ; length 12 mm. ; width 8 mm. ; height 4 mm. :
Nova Scotia to Florida, in shallow water; not so abundant as the above;
Pacific coast.

C. plana Say. Shell flat or concave, with a minute apex; white and
polished inside ; length 40 mm. ; width 25 mm. : Maine to Texas ; common
in shells from low-water mark to 487 fathoms.

FAMILY 3. LITTOEINIDAE.

Shell spiral and conical; lip not notched; aperture round, interior
not pearly; operculum horny and spiral; head projecting, tentacles

* See "The Embryology of Crepidula," by E. G. Conklin, Jour. Morph., Vol. 13,
1897.

540 MOLLUSCA

conical, with eyes at their base: several hundred species, in salt, brack-
ish, and fresh water, some being amphibious; they are mostly littoral,
and feed on algae, on which they are found.

Key to the genera of Littorinidae here described :

ot Shell thick and solid ; no umbilicus 1. LITTOBINA

oa Shell thin 2. LACUNA

1. LITTORINA Ferussac. Periwinkles. Shell conical, thick and
solid, with 4 to 6 whorls; lip acute; no umbilicus; foot longitudinally
divided, each side advancing alternately when the animal moves; radula
2 or 3 times the length of the animal: 175 species, cosmopolitan; in
shallow water; more or less amphibious.

Key to the species of Littorina here described :
Oj Shell not smooth and shining.
Z>! Shell with revolving color bands.

ct Bands continuous L. LITOREA

c, Bands broken L. IBBORATA

6a Shell without color bands L. BUDIS

c, Shell smooth and shining L. PALLIATA

L. litorea (L.). The edible periwinkle (Fig. 837). Shell not smooth,
dark brown, yellowish, or reddish in color, with dark spiral bands; inte-
rior white or brown ; length 25 mm. ; width 16 mm. : Europe, where it is
an article of food; recently introduced on our Atlantic coast, and now
very common as far south as Delaware Bay.

Fig. 837 Fig. 838 Fig. 839

Fig. 837 — Littorina litorea (Leunis). Fig. 838 — Littorina rudis (Verrill).
Fig. 839— Lacuna vincta (Verrill).

L. rudis (Donovan) (Fig. 838). Shell very solid and thick, with
usually spiral ridges and grooves, whitish to red or black in color, with
sometimes spiral bands; shell very variable in color and texture; length
14 mm.; width 10 mm.: New Jersey to the Arctic Ocean; very common;
Pacific coast; Europe.

L. irrorata (Say). Whorls flattened, yellowish-white or green in
color, with numerous revolving ridges which are spotted with short
brown lines; throat white; length 25 mm.: Vineyard Sound to Florida,
very common towards the south.

L. palliata (Say). Shell small with a low spire; surface smooth
and shining; color yellow, brown, or red, sometimes spirally banded;
length 15 mm. : New Jersey to the Arctic Ocean ; very common ; Europe.

GASTROPODA 541

2. LACUNA Turton. Shell conical and thin with about 5 whorls,
with a long umbilical groove along the columella leading to a deep
umbilicus: 16 species.

L vincta (Montagu) (Fig. 839). Shell gray or yellowish in color,
with 2 dark bands on the upper whorl and 4 on the lower one, which
may be wanting; length 12 mm.; diameter 7 mm.: circumpolar, south
to Long Island Sound and Puget Sound; very common; Europe.

FAMILY 4. KISSOIDAE.

Shell small, spiral, turreted; aperture regularly rounded, with a
slightly-expanded lip; operculum horny; eyes at the base of the ten-
tacles; epipodium with filaments: marine or brackish water; over 200
species, principally towards the south.

RISSOA Freminville. Shell minute, conical, multispiral, white in
color: 75 species, mostly in the north temperate zone in
deep water.

R. minuta (Totten). Shell thin and polished, with 5
whorls and an obtuse apex; color yellowish, which is
usually coated with a green pigment ; length 4 mm. ; diam-
eter 2 mm. : New Jersey to Gulf of St. Lawrence ; common
on seaweed and under stones.

R. aculeus (Gould) (Fig. 840). Shell thin, with 6 whorls, light yel-
lowish in color, with microscopic revolving lines ; length 4 mm. ; diameter
1.7 mm.: Long Island Sound to Greenland; common on seaweed.

FAMILY 5. HYDEOBIIDAE.

Shell small, usually elongate and conical, with a pointed spire;
aperture rounded; operculum corneous or calcareous; umbilicus usually
open: about 80 species, in fresh and brackish water; cosmopolitan.

Key to the genera of Hydrobiidae here described:

Oj Shell ovate.

6t Umbilicus closed.

Cj In eastern and central states 1. BYTHINIA

c2 On Pacific slope 3. FLUMINICOLA

6a Umbilicus open.

<?! Spire well developed 2. AMNICOLA

c2 Spire very low 4. SOMATOGYBUS

aa Shell elongate.

&! Umbilicus narrow and deep 5. POMATIOPSIS

6a Umbilicus absent or very shallow 6. PALUDESTBINA

1. BYTHINIA Gray. Shell conical, thin, covered with a thin perios-
tracum; operculum calcareous, not spiral, but with prominent growth-
ridges: in fresh water; 50 species, all in the Old World.

542

MOLLUSCA

Fig. 841 Fig. 842

Fig. 841—^BytMnia
tentaculata (Baker).
Fig. 842 — Amnicola
limosa (Baker).

B. tentaculata (L.) (Fig. 841). Shell yellowish or greenish in color,
smooth and shining, with 5 whorls, the lowest of which equals the other
four; length 11 mm.; width 6.5 mm.: a European species introduced
recently into the northern states; in lakes and ponds, often very
common; in Chicago they are sometimes drawn into
the water pipes from Lake Michigan in sufficient
quantities to block the smaller ones.

2. AMNICOLA Gould and Haldeman. Shell small,
thin, smooth, conical, with a low spire and a broad
lower whorl; operculum spiral, horny; snout short,
tentacles long: about 10 species, all in North Amer-
ica, in fresh water; 3 on the Pacific slope.

A. limosa (Say) (Fig. 842). Shell globose, plain
brown in color, without bands, shining, 5 mm. long,
4 mm. wide ; umbilicus either narrow or wide ; whorls

4 to 5 ; aperture circular ; lip sharp : entire country ; very common on the
muddy bottom or on aquatic plants in streams and ponds.

A. cincinnatiensis (Lea). Shell swollen, greenish or yellowish-
brown in color, smooth and shining, 5.5 mm. long, 4 mm. wide; whorls

5 or 6; aperture oval; lip sharp; umbilicus small and very deep: eastern
and central states ; common on the muddy bottom of streams and ponds.

3. FLTJMINICOLA Stimpson. Shell rather large, ovate, solid, without
umbilicus, smooth, outer lip projecting above over the inner lip, which
is flattened: Pacific slope, in streams and lakes.

F. nuttalliana (Lea). Shell yellowish, smooth, with 4 whorls;
aperture white; length 10 mm.; diameter 7.5 mm.: valley of the
Columbia; very common.

4. SOMATOGYRTIS Gill. Shell globose, with a short low
spire and a very large inflated lower whorl and large
oblique aperture; whorls 4; lip thin; operculum spiral,
horny: about 6 species, all in the central states, in fresh
water.

5. subglobosus (Say) (Fig. 843). Shell yellowish in
color, shining; apex rounded; length 7 mm.; width 6.5
mm.; umbilicus small: central states, west to Iowa.

S. integer (Say). Shell yellowish, shining, 4 mm. long and 3 mm.
wide; umbilicus almost obliterated by a callus: central states, west to
Iowa.

5. POMATIOPSIS Tryon. Shell small, elongate, and conical; umbili-
cus narrow and deep; aperture round or oval; operculum spiral and
corneous; peristome thin: North America; air breathers,, although
possessed of a gill.

Fig. 843

Somatoyyrus

subglobosus

(Baker).

aASTROPODA 543

P. lapidaria (Say) (Fig. 844). Shell slender, dark brown in color,
and shining, with 6 whorls, 6.5 mm. long and 3 mm. wide: eastern and
central states, under stones on the margin of streams or in moist places
on land or on aquatic plants; common.

P. cincinnatiensis (Anthony). Shell robust, with 4 or
5 whorls, greenish or brown in color, and shining, 4.5 mm.
long and 2.3 mm. wide: central states, in moist places on
land, or on stones in the water.

P. californica Pilsbry. Shell thin, brown in color, 5
mm. long : San Francisco and Oakland.
6. PALUDESTRINA D'Orbigny. Shell small, elongate, conical, with
an elevated spire; apex generally obtuse; aperture ovate; lip thickened;
operculum horny: in fresh water.

P. nickliniana (Lea) (Fig. 845). Shell with 6 whorls, greenish in
color, shining, 4.5 mm. long, 2 mm. wide; umbilicus indented: eastern
and central states; often common on aquatic vegetation in ponds and
rivers.

FAMILY 6. SKENEIDAE.

Shell small, with a very low spire, being almost discoidal, and a
wide umbilicus ; operculum horny, multispiral : 1 genus, in northern seas.

SKENEA Fleming. With the characters of the family: 1 American
species.

Fig. 845 Fig. 846 Fig. 847

Fig. 845 — Paludestrina nickliniana (Baker). Fig. 846 — Skenea planorbis (Verrill).
Fig. 847 — Vivipara contectoides ( Baker j.

S. planorbis (Fabricius) (Fig. 846). Shell minute, flat, with 3
whorls, yellowish, smooth; aperture circular; length .8 mm.; width 1.3
mm.: Long Island Sound to Greenland; common under stones near low-
water mark; Pacific coast; Europe.

FAMILY 7. VIVIPAKIDAE. (PALUDINIDAE.)

Shell conical or globose, with rounded whorls and an olive-green
periostracum ; aperture simple, roundish; operculum horny and usually
not spiral; animal with a prominent, broad snout, and eyes on short
stalks at the outer base of the stout tentacles; viviparous, the young
remaining in the parent shell for some time after hatching : about 6
genera and over 200 species; in fresh water in all parts of the world.

544 MOLLUSCA

Key to the genera of Viviparidae here described :

«! Shell banded, with umbilicus 1. VmPABA

a, Shell not banded, without umbilicus.

&! Shell thick and solid 2. CAMPELOMA

ba Shell thin 3. LIOPLAX

1. VIVIPARA Lamarck (Paludina Lam.). Shell thin, with about 5
whorls and a small umbilicus : 100 species, cosmopolitan ; about 8 Amer-
ican species, mostly in the southern states; about 2 on the Pacific slope.

V. contectoides Binney (Fig. 847). Shell with 4 revolving brown
bands, of which 3 are on the body of the whorl and 1 on the base, the
upper whorls showing but 2 bands, sometimes indistinct or wanting;
length 33 mm.; width 25 mm.: eastern and central states, in lakes and
rivers, on muddy bottoms in shallow water.

2. CAMPELOMA* Rafinesque. Shell solid, thick, with-
out umbilicus; whorls 6: about G species, all in North
America.

Key to the species of Campeloma here described:

ch Spire shorter than the aperture C. PONDEROSUM

aa Spire and aperture of equal length.

&x Whorls rounded C. DECISUM

62 Whorls flattened C. SUBSOLIDUM

C. ponderosum (Say) (Fig. 848). Shell very heavy and solid, con-
ical, with a very large lower whorl and an elongate ovate aperture;
color greenish or blackish; length 21 mm.; width 15 mm.; aperture
longer than the spire: New York to Illinois, south to Alabama.

C. decisum (Say). Shell rather solid, conical; spire about as long
as the aperture ; length 28 mm. ; width 17 mm. ; color dark green, surface
shining: New England to Iowa; south to Tennessee.

C. subsolidum (Anthony). Shell very solid, yellowish or light
green in color, smooth; whorls 6, flattened; aperture sigmoid; length
40 mm.; width 23 mm.: New England to Illinois, south to central Ohio.

3. LIOPLAX Troschel. Shell thin, conical, and elongate; without
umbilicus; foot very large: 2 species, both in the United States.

L. subcarinata (Say). Shell with 3 or 4 whorls, which are with
2 or 3 indistinct ridges; operculum spiral in the center, except in old
shells; aperture oval; length 12 mm.; width 10 mm.; color greenish:
New Jersey to Indiana.

FAMILY 8. VALVATIDAE.

Shell small, conical, and depressed or discoidal, with an open
umbilicus; operculum corneous, circular, multispiral; periostracum

* See "On the Genus Campeloma," etc., by R. E. Call, Bull, Washburn Coll. Lab.,
Vol. 1, p. 149, 1886,

GASTROPODA 545

greenish ; tentacles long and slender with eyes at their outer base ; snout
prolonged; ctenidium bipectinate, long, exposed; animals hermaphro-
ditic: the temperate regions of the globe, in rivers, ponds, and lakes;
1 genus.

VALVATA 0. F. Miiller. With the characters of the family: about
6 American species, 3 being on the Pacific slope.

Key to the species of Valvata here described:

<z, Whorls of shell rounded V. SINCERA

aa Whorls keeled.

&t Apex elevated , V. TEICABINATA

62 Apex not elevated V. BICABINATA

V. sincera Say (Fig. 849). Shell conical and depressed, with 3 or
4 whorls; spire very low; lowest whorl very large, rounded; aperture
round, beneath the rest of the shell; surface shining and brownish in
color ; length 2.5 mm. ; width 4.5 mm. : Canada
and Alaska and the northern states towards the
north; in lakes and sluggish streams.
Fig. 849 Fig. 850 V. tricarinata (Say) (Fig. S50). Shell

Fig. 849— Valvata sincera depressed, thin, shining, whitish or greenish
t^wtofjuw™™** in color> with an elevated spire flattened at
the apex; whorls 3 or 4, with deep sutures,

and with 1 to 3 prominent keels on the outer surface; length and width
4 mm. : northern states, south to Iowa ; very common.

V. bicarinata Lea. Shell discoid, the spire not elevated, and with
no more than 2 keels ; length 3.5 mm. ; width 5 mm. : northern states.

FAMILY 9. AMPULLABIIDAE.

Shell with a low spire and a large lower whorl and aperture; snout
divided into two long tentacular lobes; tentacles long and slender, with
eyes on short stalks at their outer base; mantle with a long siphon on
the left side; respiratory cavity divided by a partition, the left acting
as a pulmonary sac, the right containing a very large ctenidium: numer-
ous species; in fresh water, principally in tropical regions.

AMPULLARIA Lamarck. With the characters of the family; um-
bilicus widely open: 150 species.

A. depressa Say. Shell with 4 whorls, yellowish in color, with
numerous revolving brown or greenish bands; 37 mm. long and wide:
Florida and Georgia, in rivers and lakes.

FAMILY 10. CEEITHIIDAE.

Shell elongate, with a tall spire and a ridged or tuberculated sur-
face; aperture channeled in front, forming a short canal, and usually

546 MOLLUSCA

with an expanded outer lip; operculum horny and spiral; mantle with
a short siphon : 200 species, in salt, brackish, and fresh water.
Key to the genera of Cerithiidae here described:

(^ Shell dextral.

&i Outer lip not expanded 1. BITTIUM

63 Outer lip expanded 3. CEEITHIOPSIS

a, Shell sinistral 2. TBIFOBIB

1. BITTIUM Leach. Shell with a granular surface; aperture with
a slight canal in front; outer lip acute, not expanded; operculum with
4 spirals : numerous species.

B. alternatum (Say) (B. nigrum Stimpson) (Fig.
851). Shell slender, with about 8 whorls, bluish or blackish
in color, 6 mm. long and 2 mm. wide ; surface covered with
a fine network of elevated lines ; aperture rounded : Massa-
chusetts Bay to New Jersey; in shallow water.

2. TRIFORIS Deshayes. Shell sinistral; aperture
round, prolonged in front to form a closed tube: 100
species, mostly towards the south.

T. perversa (L.) (T. nigrocincta Adams). Shell reddish-black in
color, with 3 revolving series of granules; whorls 12 or more; length 7
mm.; width 1.7 mm.: Cape Cod to west Florida; rather
common; Europe; California.

3. CERITHIOPSIS Forbes and Hanley. Shell slender,
frequently with longitudinal ribs; aperture with an an-
terior canal and a less distinct posterior one; operculum
horny and spiral: in shallow water.
Fig. 852 0. greeni (Adams) (Fig. 852). Shell with 10 to 12

greeni whorls, reddish-black in color, with longitudinal ridges

and revolving lines, forming series of granules; length 5
mm.; width 1.2 mm.: Massachusetts Bay to Texas.
C. terebralis (Adams). Shell with 10 to 12 whorls, flattened and
having 3 revolving ridges on each, with numerous fine longitudinal
lines between the ridges; length 12 mm.; width 3 mm.; color reddish-
brown: Cape Cod to Texas.

FAMILY 11. PLEUROCEBIDAE.

Shell elongate, conical, with numerous whorls; operculum spiral;
aperture round or ovate, and rather small and channeled or angulated
in front; animal with a broad, short snout and with eyes sessile,
situated at the base of the tentacles: in fresh water; many hundred
species, all in the United States (except 2 or 3 in Mexico), mostly in
the southern states.

GASTEOPODA 547

Key to the genera of Pleuroceridae here described :

Oj Aperture lengthened to form a short canal ; whorls flattened . 1. PLEUBOCEBA
o, Aperture not canaliculate ; whorls rounded 2. GONIOBASIS

1. PLETJROCERA Rafinesque. Shell with a long, tapering spire ; outer
lip with a projection about the middle forming a short siphonal canal;
surface smooth or ribbed; without umbilicus: 84 species.

P. subulare (Lea) (Fig. 853). Shell yellowish-brown in color, with
a yellowish band encircling the whole just below the suture; whorls 11,
increasing regularly, the upper 7 with a slight revolving ridge, the
lower 4 rounded; length 22 mm.; width 8 mm.: upper Mississippi and
valley of the Great Lakes, usually on sandy or rocky bottoms.

P. elevatum (Say) (Fig. 854). Shell yellowish or greenish in color,
with a yellowish band just below the suture and two purplish bands

Fig. 853 Fig. 854 Fig. 855

Fig. 853 — Pleurocera siibulare (Baker). Fig. 854 — Pleurocera, elevatum (Baker).
Fig. 855 — Goniobasis livescens (Baker).

at the center of the whorls; whorls flattened, with revolving ridges;
aperture triangulate : chiefly in the drainage of the Ohio River, on sandy
or rocky bottoms.

2. GONIOBASIS Lea. Shell rather heavy, elongated, with a long
and more or less pointed spire; aperture not channelled: 274 species.

G. livescens (Menke) (Fig. 855). Shell pinkish, yellowish, or
greenish in color, often with two dark brown bands; surface shining,
with a slight revolving ridge in the center of all the whorls but the
last 2; length 20 mm.; width 9.5 mm.; whorls 7 to 9, rounded; aperture
ovate, purple inside; outer lip very convex and elongated below: valley
of the Great Lakes; in shallow water containing vegetation.

G. virginica (Gmelin). Shell slender, dark brown in color; length
30 mm.; whorls 6, somewhat rounded: Delaware and Schuylkill Rivers;
common.

FAMILY 12. TUBBITELLIDAE.

Shell elongate, with a very long spire on which are revolving ridges;
no umbilicus; operculum multispiral and horny; tentacles long, with
eyes at their base; mantle fringed, with a siphon; aperture round,
without a canal: 190 species; marine.

548 MOLLUSCA

TURRITELLA Lamarck. Aperture round; shell usually brown, with
brownish spots: 75 species; cosmopolitan; mostly in deep water.

T. acicula Stimpson. Shell small, white, and thin, with 10 whorls,
6 mm. long; 2 mm. wide; Cape Cod to Eastport, Maine, in rather deep
water.

T. variegata (L.). Shell 10 cm. long, with 16 flattened whorls;
surface variegated with brown and white: Florida and West Indies.

FAMILY 13. VEEMETIDAE.

Shell tubular, irregularly spiral at the apex, with the lower whorls
free and extended; interior of shell partitioned off by smooth, concave
septa; aperture round; foot rudimentary; head long, with 2 conical ten-
tacles with eyes at their base; 2 additional tentacles at the side of the
mouth; operculum circular, horny; animals stationary: 120 species, in
all temperate and warm seas.

VERMET.US Adanson. "With the characters of the family; shell
attached or free: numerous species.

V. (Vermicularia Lamarck) radicula Stimpson (Fig. 856). Spiral
portion with ab^ut 8 whorls and 12 mm. long, remainder of shell some-
times 20 cm. long : Cape Cod to Florida in shallow water,
several shells usually intertwined together; common
towards the south.

FAMILY 14. STEOMBIDAE.

Shell usually large and solid, with a conical spire and
a very large lower whorl; aperture long and narrow; lip
expanded, sometimes forming digitations, and with a deep
notch near the lower edge; foot long and narrow, with a

r Ig. out)

Vermetus iong arched metapodium which bears the small claw-

radicula

(Verrili). shaped operculum, and used for springing and not for

walking; eyes large, at the end of a pair of long stalks;
snout long: 100 species, in tropical and subtropical seas; several species
in the West Indies and southern states.

1. STROMBUS L. Shell ovate, usually with protuberances; lip plain
or lobed: 60 species, 5 American.

S. gigas L. Conch. Length 25 cm. and more; weight up to 5
pounds; surface roughened and with protuberances; interior pink:
Florida Keys and West Indies; very common; used for food; the shell
is used to make cameos and ornaments, and also often as a dinner
horn; the largest shell on the Atlantic coast and the largest mollusk
in the country.

GASTROPODA

549

S. pugilis L. (Fig. 857). Length 9.5 cm.; color reddish-brown;

spire acute, with protuberances; interior pink: Cape Hatteras to

Panama, in shallow water.

2. PTEROCERA Lamarck. Outer lip of shell

with long finger-like processes: 10 species in

Pacific and In-
dian Oceans.

P.lambis(L.).
Finger shell (Fig.
858). Length 15
cm. ; 6 fingers and
a finger-like si-
ph on a 1 canal
present: Indian
Ocean ; used as
ornaments.

3. APORRHAIS Dillwyn. Shell with a
tall spire; aperture large; lip very much
thickened and expanded, the outer lip
being widely dilated: 4 species, in the
North Atlantic.

A. occidentalis Beck. Shell solid,
conical, with 9 whorls which have arched,
transverse ridges; outer lip dilated and
wing-like; color whitish; length 6 cm.;
width 35 mm.: Cape Cod, northwards,
occasionally found on the beach.

Fig. 857
Strombus pugilis (Rogers).

Fig. 858 — Pterocera lambis
(Rogers).

FAMILY 15. CYPE^EIDAE.

Shell solid, ovate, very smooth and polished, and often brightly
colored; spire often concealed by the last whorl, which is then as long
as the shell; aperture narrow and channeled at each end; no operculum;
foot broad; mantle expanded on each side and meeting over the back:
several hundred species, mostly in tropical and subtropical seas.

1. CYFR^A L. Cowries. Shell ovate, flattened
beneath, with the spire concealed; aperture toothed
on both sides; outer lip turned in: 200 species,
mostly in the Indian and Pacific Oceans, where the
beautiful shells are much used for ornaments.

C. moneta L. (Fig. 859). True cowry. Shell yellow to white in
color; 3 cm. long: Indian and Pacific Oceans; very common; used in
Africa and other places as money.

Fig. 859 — Cyprcea
moneta (Rogers).

550

MOLLUSC A

C. exanthema L. Shell brown in color, with round white spots
which may have brown centers, and a mid-dorsal yellow band; lip
violet within; length 11 cm.: Cape Hatteras to Panama, in shallow
water.

C. spadicea Gray. Nut-brown cowry. Shell dark brown above and
lighter in the center; lips white; length 5 cm. or less: California; not
common.

2. TRIVIA Gray. Coffee-bean shells. Similar to Cypraea, but with
transverse ribs, and much smaller: 45 species; cosmopolitan.

T. californica Gray. Shell reddish-chocolate in color
and white inside, with a dozen sharp ribs; length 10 mm.:
California, in shallow water.

T.pediculus(L.) (Fig.
860). Shell pinkish, with
G black spots on the back
and 20 mm. long : Florida.

3. OvULUM Bruguiere. Shell spindle-
shaped, the aperture being drawn out at
both ends into a canal ; inner lip smooth ;
outer lip toothed or smoth: 75 species;
in tropical seas.

0. ovum (L.) (Fig. 861). Shell egg-shaped, white, with a yellow
aperture; length 9.5 cm.: Indian Ocean; used for ornaments.

Fig. 860

Trivia pedieu

lus (Rogers).

Fig. 861 — Ovulum ovum (Rogers).

FAMILY 16. DOLIIDAE.

Shell large, thin, with a short spire and a very large swollen whorl,
and covered with revolving ridges; operculum wanting; head long and
wide ; proboscis very long ; foot very large : about 30 species ; in tropical
seas; shell often used as domestic utensils.

DOLIUM L. Shell ovate; outer lip crenulated: 15 species, 4 on
the South Atlantic coast.

D. galea L. (Fig. 862). Shell brownish-yellow in color, with
rounded revolving ribs; length 25 cm.: Cape Hatteras to Texas; the
West Indies, in shallow water; Mediterranean.

FAMILY 17. CASSIDIDAE.

Shell thick, triangular or fusiform; spire short, partially immersed;
aperture long and narrow, terminating below in a short curved canal;
columella covered with a broad callus; outer lip broad, ribbed within;
operculum horny: 60 species, in tropical seas; about 7 on the South
Atlantic coast.

GASTROPODA

551

CASSIS Lamarck. Shell solid, last whorl very large; canal short
and bent backwards : 37 species, which are much used in cutting cameos.
C. cameo Stimpson. Length 25 cm.; yellowish-white, tinged with
yellowish-brown; lip and columella very broad, yellowish-cream color,
with dark brown teeth and ridges: North
Carolina to west Florida; West Indies.

Fig. 862 Pig. 863

Fig. 862 — Dolium galea (Rogers). Fig. 863 — Cassis tulerosa (Rogers).

C. tuberosa (L.) (Fig. 863). Length 20 cm.; surface crossed by
numerous fine grooves, both longitudinal and spiral; color yellow, with
brown blotches; lower whorl with 3 rows of protuberances: North
Carolina to west Florida; West Indies.

FAMILY 18. TEITONIDAE.

Shell solid, conical or fusiform, with a high spire; surface rough;
outer lip thickened and turned in; operculum horny; aperture with a
canal: 150 species, in tropical seas.

TRITON Montfort. Tritons. Shell conical, with a crenulated outer
lip; whorls roughened by transverse and longitudinal
ridges : 100 species, in tropical seas ; the largest snails, the
shells being often used as trumpets.

T. nodif eras Lamarck. Length 45 cm.; color brown
and white; aperture red: Mediterranean Sea, East Atlan-
tic, Indian, and Pacific Oceans ; often used as a shepherd 's
horn or a war horn.

T. tritonis (L.) (Fig. 864). Length up to 50 cm.;
color brown, white, and red; aperture red: Gulf of
Mexico; Indian Ocean.

Fig. 864
Tritonium

tritonis
(Leunis).

SUBDIVISION 2. HETEROPODA.

Pelagic, transparent prosobranchs in which the foot is a swimming
organ, and is made up of two parts, a compressed fin-like structure

552

MOLLUSCA

(propodium and mesopodium) which projects ventrally and often bears
a sucker, and a tail (metapodium) which projects posteriorly, and in
some forms bears an operculum; head large, bearing a pair of tentacles
with large eyes on short stalks at their base; the principal viscera form
a sort of nucleus, often brightly colored, dorsally situated and covered,
in most cases, by a transparent shell; sexes separate: about 60 species,
all of which live on the high sea, often in large schools, in tropical and
subtropical regions, eating fishes, Crustacea, and other small animals;
2 families.

Key to the families of Heteropoda:

Oj Shell much too small to contain the animal and sometimes absent.

1. PTEROTRACHEIDAE
ca Shell multispiral, containing the body 2. ATLANTIDAE

FAMILY 1. PTEROTRACHEIDAE.

Body elongate, cylindrical, transparent, naked or with a small, trans-
parent, conical, cap-shaped shell which covers the small nucleus alone,
and from which projects the ctenidium: 4 genera and about 30 species.

Fig. 865

Fig. 866

Fig. 867

Fig. 865 — Carinaria mediterranea (Cambridge Natural History). 1, sucker; 2, fin;

3, shell; 4, gill; 5, tentacle. Fig. 866 — Atlanta peroni (Leunis).

Fig. 867 — Eulima oleacea (Verrill).

CARINARIA Lamarck. Small conical shell present: 8 species in
tropical and subtropical seas; 1 species on the South Atlantic coast.

0. mediterranea Peron and Lesueur (Fig. 865). Body 20 cm. long
or less; snout violet; foot red: New Jersey to Florida; West Indies;
Mediterranean Sea.

FAMILY 2. ATLANTIDAE.

Shell spiral and discoid and large enough to receive the entire
body: 22 species, in 2 genera.

1. ATLANTA Lesueur. Shell small, thin, compressed, with a promi-
nent keel on the periphery; aperture narrow, with a deep notch at the
keel; operculum ovate: 18 species, 6 on the South Atlantic coast.

A. peroni Les. (Fig. 866). Length 8 cm.: New Jersey to Texas;
West Indies; Mediterranean.

GASTROPODA 553

2. OXYGYRTTS Benson. Shell" milky white, rounded on the periph-
ery and keeled only near the aperture, which has no notch : 4 species, 1
on the South Atlantic coast.

0. keraudreni D'Orbigny. New Jersey to Texas; West Indies.

DIVISION 3. GYMNOGLOSSA.

Similar to the Tcenioglossa except that the radula and jaws are 'absent :
2 families, both marine.

Key to the families of Gymnoglossa:

ax Apical whorls normal ; animals often parasitic 1. EULIMIDAE

ca Apical whorls sinistral , 2. PYBAMIDELLIDAE

FAMILY 1. EULIMIDAE.

Shell usually elongate, conical, and multispiral, white hi color and
polished; foot long and narrow; proboscis very long, sometimes longer
than the body; animal often parasitic, sucking the juices of its host by
means of the long proboscis: 5 genera and numerous species.

1. ETJLIMA Risso. Shell slender, tall, sometimes bent; operculum
horny, spiral: 50 species, mostly southern, many parasitic.

E. oleacea Kurtz and Stimpson (Fig. 867). Shell small, solid,
with 12 flattened whorls; color pale brown; aperture small, oval; length
6 mm.; width 1.5 mm.: Vineyard Sound to North Carolina; parasitic
on Thy one briareus.

2. STYLIFER Broderip. Shell thin, transparent, ovate or elongate,
with a very sharp apex which is sometimes bent; operculum wanting;
aperture small ; tentacles slender ; eyes sessile : 20 species ; cosmopolitan ;
parasitic on or in the integument of echinoderms, often producing tumors.

S. stimpsoni Verrill. Shell white, swollen, with 4 to 5 whorls, the
lowest very large, with an impressed revolving line just below the
suture; length 3.75 mm.: Massachusetts to New Jersey; on Strongylo-
centrotus.

FAMILY 2. PYEAMIDELLIDAE.

Shell conical, elongate or ovate, usually small, with apical whorls
sinistral and excentric; operculum horny, spiral; tentacles ear-shaped,
joined at the base; eyes sessile: several hundred species.

Key to the genera of Pyramidellidae here described:

O! Columella without a fold 1. TURBONILLA

aa Columella with an oblique fold 2. ODOSTOMIA

1. TURBONILLA Risso. Shell long and slender and multispiral,
white or yellow, ribbed or striate; lip incomplete: 50 species;
cosmopolitan.

554 MOLLUSCA

T. elegans Verrill (Fig. 868). Whorls rounded, with numerous
longitudinal ribs and fine revolving grooves; color light yellow; length
9 mm.; width 2.5 mm: Massachusetts Bay to Florida, in
shallow water.

T. intermpta (Totten). Shell very slender and
pointed, with 8 or 10 convex whorls, on which are 20 to
30 ribs crossed by about 14 revolving lines: Cape Cod to
South Carolina, in shallow water; common.
Turionttia, 2- ODOSTOMIA Fleming. Shell minute, elongate, con-

(Verrnf). ical> thin; aperture ovate; columella with an oblique

fold: 100 species; cosmopolitan.
Key to the species of Odostomia here described :

o, Surface smooth.

&! Color dark brown O. FUSCA

6a Color glossy white . .O. TBIFIDA

&3 Color greenish with a line under the suture O. BISUTUKALIS

aa Surface granulated O. SEMINUDA

0. bisuturalis (Say). Shell conical, smooth, light green; periostra-
cum brown, with a single revolving line below the suture ; length 5 mm. ;
diameter 2.5 mm. ; 6 whorls : Massachusetts Bay to New Jersey ; common
under stones.

0. fusca (Adams). Shell elongate, rather blunt, dark brown, glossy,
with 6 or 8 whorls ; 6 mm. long ; 1.8 wide ; umbilical indentation present :
Cape Cod to New Jersey, in shallow water; common.

0. trifida (Totten). Shell elongate; apex acute;
whorls 8, flat, with about 6 revolving lines; color white;
length 5 mm.; width 2 mm.: Massachusetts Bay to New
Jersey, in shallow water; common.

0. seminuda (Adams) (Fig. 869). Shell with an Odostomia

seminuda
acute apex, 6 or 7 whorls, with coarse revolving lines (Verrill).

crossed by longitudinal ones, giving the surface a granu-
lated appearance; color glossy white; length 4 mm.; width 2 mm.:
Massachusetts Bay to west Florida; common in shallow water.

DIVISION 4. RACHIGLOSSA.

Radula long and narrow, with 3 longitudinal rows of teeth (Fig.
870), a central and two lateral, each tooth, in most species, consisting
of a base and several cusps; proboscis long and retractile; siphon dis-
tinct and usually long; operculum usually present, and always horny
and non-spiral; shell spiral, usually thick, often with tubercles or
spines; aperture elongate, prolonged below to form a siphonal canal:
12 families, marine (excepting a few species) ; carnivorous.

GASTROPODA 555

Key to the families of Rachiglossa here described:

di Shell rough, with ridges, tubercles, or spines.

&i Central teeth without cusps 2. COLUMBELLIDAE

6a Central teeth with cusps.

cx Laterals without cusps 1. MURICIDAE

ca Laterals with 2 or 3 cusps.

dt Centrals with many cusps 3. NASSIDAE

da Centrals with 5 to 7 cusps 4. BUCCINIDAE

d3 Centrals with 2 cusps 5. TUBBINELLIDAE

oa Shell smooth and polished.

&! Shell with a tall spire 6. MITBIDAE

6, Shell with a low spire 7. OLIVIDAK

FAMILY 1. MURICIDAE.

Shell thick and solid, with an elevated spire with a rough surface
on which are usually rows of protuberances or spines; siphonal canal
often long; eyes sessile, at the outer base of
the tentacles; central tooth of radula with
at least 3 long cusps (Fig. 870, 1) ; laterals
without any: about 15 genera and 1,000 spe-
cies, which are mostly tropical; they feed
largely on other mollusks, the shells of which ^ 870_Radula of Murex
they are able to pierce with the radula in the (£™*1^n^?2$tS&
proboscis.

Key to the genera of Muriddae here described :

0^ Whorls angular, with distinct protuberances or spines.

6X Spines and protuberances usually very prominent 1. MUREX

Z>2 About 10 longitudinal ridges : 3. EUPLEUBA

a? Whorls rounded.

&! Longitudinal ridges very distinct 2. UBOSALPINX

1), Revolving ridges very distinct 4. PURPURA

1. MUREX L. Spiny rock-shell. Shell thick, ovate or elongated;
spire prominent; 3 or more rows of prominent protuberances or spines;
aperture round, ending below in a long canal: about 300 species, in
tropical and temperate seas. It was largely from M. trunculus L. and
M, brandaris L. that the well known Tyrean or imperial purple dye of
the ancients was obtained, a large mucous gland in the mantle furnishing
a yellowish secretion which turns purple on exposure to the light. The
secretion was obtained by crushing the animals, and large heaps of the
broken shells of these two species may now be found where ancient manu-
factories of the dye existed, M. trunculus being found principally on the
Syrian coast and M. brandaris in Greece and Italy.

M. festivus Hinds. Length 5 cm.; width 2.5 cm.; color white;
canal closed: Californian coast, towards the south.

556

MOLLUSCA

M. pomum Gmelin (Fig. 871). Length 12 cm.; color yellowish-
brown; surface rough; aperture round and yellow in color, the outer

lip having 3 brown spots: Beaufort, N. C.,
and southwards; West Indies; common.

2. UROSALFINX Stimpson. Shell fusi-
form, surface roughened by about 12
rounded, longitudinal ridges; lip scalloped;
aperture with a short canal: 20 species.

E. cinereus (Say). Oyster drill (Fig.
872). Shell 25 mm. long, 15 mm. wide,
brown or gray in color, brownish within;
whorls 5 or 6, with numerous revolving1 lines
which cross the longitudinal ridges : Florida
to Massachusetts Bay, and locally further
north, also at San Francisco; very common
on oyster beds, being one of the worst ene-
mies of the oyster, which it kills by drilling
a small round hole through the shell, through
which it thrusts its long proboscis.

3. EUPLEURA Adams. Shell fusiform; surface roughened by about
10 longitudinal ridges; whorls 7 and angulated, there being a shoulder
beneath the suture: 5 species.

E. caudata (Say) (Fig. 873). Shell 25 mm. long, 15 mm. wide,
brown or gray in color; aperture oval, with a long straight canal; lip

Fig. 871

Murex pomum (Rogers).
1, siphonal canal.

Fig. 872

Fig. 873

Fig. 874

Fig. 872 — Urosalpinx cinereus (Verrill). 1, siphonal canal. Fig. 873 — Eupleura
caudata (Verrill). Fig. 874 — Purpura lapillus (Verrill).

thick, roughened within: Cape Cod to west Florida, in shallow water;
rather common.

4. PURPURA Bruguiere. Shell oval, lowest whorl large, with a large
aperture, the canal being reduced to a notch at its lower end; columella
flattened; outer lip simple: 60 species; cosmopolitan; several species.

P. lapillus (L.) (Fig. 874). Shell thick, with 5 or 6 whorls; spire
acute; whorls with deep revolving furrows; lip arched, with ridges

GASTROPODA 557

within the margin; color whitish, yellowish, or reddish, often, banded;
length 30 mm.; width 17 mm.: eastern end of Long Island to Green-
land, in shallow water on rocks; common, feeding on oysters and other
mollusks; Europe.

FAMILY 2. COLUMBELLIDAE.

Shell conical, elongate, covered by a periostracum ; aperture narrow,
elongated, terminating below in a notch; lip thick, crenulated or toothed
within; operculum very small; central tooth of radula
without cusps; laterals with 2 or 3 cusps: 1 genus.

COLUMBELLA Lamarck. With the characters of the
family: 300 species, mostly subtropical.

C. (Astyris Adams) lunata (Say) (Fig. 875). Shell
small, with 6 whorls; surface rather flat, smooth, with a Colu'mbella
single revolving line and a few near the base; color (Verriii).
brownish, with 2 or 3 series of crescentic yellow spots on
the lower whorl; length 5 mm.; width 2.5 mm.: Massachusetts Bay to
Florida, in shallow water; common.

C. (Anachis Adams) avara Say. Shell small, with 6 whorls; surface
rather flat,, yellowish in color, blotched with brown ; lowest whorl with
10 to 15 longitudinal ridges crossed by revolving lines; length 12 mm.;
width 5.5 mm.: Cape Cod to Florida, in shallow water; not so common
as C. lunata.

FAMILY 3. NASSIDAE.

Mud snails. Shell small, conical or ovate, with an elevated spire,
thick and solid; aperture round or oval, ending below with a short canal
or a notch; columella with a callus; outer lip
thickened, toothed or crenate; operculum horny;
central teeth of radula with many cusps ; laterals
with 2 large and several small ones: 175 species.
NASSA Lamarck. Foot square in front, bi-
furcate behind or not; operculum with a serrate
Fig. 876 Fig. 877 or plain margin: 130 species; cosmopolitan; in
Fig. 876— Nassa vibex shallow water; they are scavengers, but are also

obsoieta (Verriii). predacious, destroying mollusks after the manner

of the oyster drill.

N. vibex Say (Fig. 876). Shell conical, with 6 whorls; sutures not
impressed ; surface of body whorl with about 12 undulating, longitudinal
ridges and 12 revolving lines; color whitish or brown, with a revolving
darker band; foot bifurcate behind; length 12 mm.; diameter 8 mm.:
Cape Cod to Gulf of Mexico; common south of Cape Hatteras; West
Indies.

558 HOLLUSCA

N. (Tritia Risso) trivittata Say. Shell conical, with 7 whorls;
sutures impressed, with a shoulder below; surface with numerous longi-
tudinal and revolving creases dividing it into series of large granules;
foot bifurcate behind; color greenish-white, often with brown revolving
bands, white within; length 18 mm.; width 8 mm.: Florida to Gulf of
St. Lawrence; common.

N. (Ilyanassa Stimpson) obsoleta Say (Fig. 877). Shell conical,
with 6 whorls, the lower one being large ; surface covered with numerous
longitudinal and revolving creases, giving it a reticular appearance;
foot not bifurcate behind ; margin of operculum not serrate ; color brown,
purple or black within; length 25 mm.; width 12 mm.: Gulf of St. Law-
rence to west Florida; the commonest snail south of Cape Cod.

FAMILY 4. BUCCINIDAE.

Shell usually thick and ovate or pear-shaped, with a conical spire
and a large lower whorl; aperture usually large, ending below in a wide
notch or a short, wide siphonal canal; central tooth of radula with 5
to 7 cusps ; laterals with 2 or 3 : over 1,100 species.

Key to the species of Buccinidae here described :

«! No distinct canal 1. BUCCINUM

a, Distinct canal 2. NEPTUNEA

1. BUCCINUM L. Whelks. Shell covered with a horny periostra-
cum; aperture with a wide notch at the lower side and about as long as
the spire: 30 species, in colder waters.

B. undatnm L. Shell with 6 whorls and grayish in color, with about
12 prominent crescentic or oblique longitudinal ridges, which disappear
towards the tip and are crossed by numerous raised revolving lines;
aperture oval, usually yellow, but sometimes white within; length 60
mm.; width 35 mm.: New Jersey to Greenland, from low
to deep water; common north of Cape Cod; Europe,
where it grows larger than here, and is a common article
of food, and is also used extensively as bait for cod.

2. NEPTUNEA Bolton (Chrysodomus Swainson). Shell
Fig. 878 fusiform, covered with a horny periostracum ; spire ele-

pygmKa vated ; aperture oval, shorter than the spire, with a short
CVerrill). _ *. „ ' . , .

canal, white or yellowish in color: circumpolar, about 15

species on the Atlantic coast, mostly in deep water.

N. pygmaea (Gould) (Fig. 878). Shell with an elevated spire, with
6 whorls and a small, elongate aperture, ending below in a rather long
canal; periostracum hirsute; length 20 mm.: Long Island Sound to the
Gulf of St. Lawrence, in 10 to 640 fathoms.

GASTROPODA

559

N. decemcostata (Say). Shell with 6 whorls, with 10 rounded re-
volving ridges on the lower whorl/ and 2 on the upper; color white;
ridges horn-colored; length 75 mm.; width 45 mm.: Cape Cod and
northwards, in rather deep water, often thrown up on the beach.

capsules of Busycon canaliculatum
(Rogers).

FAMILY 5. TUKBINELLIDAE.

Shell fusiform or pear-shaped; aperture elongate, with a long
siphonal canal; central tooth of radula with 3, laterals with 2 cusps:
about 8 species on the Atlantic coast.

1. BTJSYCON Bolton (Fulgur Montfort). Conchs. Shell large, with
a short spire and a very large lower whorl, which tapers below into a
long twisted canal;
aperture large ; outer
lip thin and smooth;
whorls 6: 5 species on
the eastern coast of Fig. 879— Egg
the United States; egg
capsules lens-shaped, about 25 mm. wide, attached in a row to a common
chord (Fig. 879).

Key to the species of Busycon here described:

at No sutural canal.

&x Shell dextral B. CABICA

63 Shell sinistral B. PEBVERSUM

a. Revolving canal at suture B. CANALICULATUM

B. carica (L.). Shell thick, solid; spire
conical, with a flattened surface and a
revolving series of prominent tubercles
above the suture; length 22 cm.; width 11
cm.; color gray or brownish: Cape Cod to
the Gulf of Mexico, in shallow water; com-
mon, especially towards the south; the
largest shell on the coast except Strombus
gigas.

B. canaliculatum (L.) (Fig. 880). Shell
thin, covered with a hirsute periostracurn,
and with a deep, broad canal at the suture;
length 13 cm.; color brownish, with numer-
ous revolving lines: Cape Cod to Gulf of
Mexico, in shallow water; very common.
B. perversum (L.). Shell similar to B. carica, but sinistral: Cape
Hatteras to Texas; West Indies.

Fig. 880 — Busycon canalicu-
latum (Rogers).
1, siphonal canal.

560

MOLLUSCA

FAMILY 6. MITRIDAE.

Shell smooth and polished, elongate, conical, with a high spire and
a small, narrow aperture; columella with folds: several hundred species,
in tropical seas.

MITRA Lamarck. Shell thick; outer lip thick and smooth within:
200 species, including many beautiful shells which are used as ornaments.

M. papalis (L.). Papal mitre. Length 13 cm.; a revolving row of
tooth-like folds on the suture; color white, with irregular red spots:
Indian Ocean; often used as ornaments.

M. swainsoni Broderip (Fig. 881). Length 8 cm.; surface with
numerous fine revolving stripes: North Carolina and southwards.

Fig. 881

Fig. 882

FAMILY 7. OLIVIDAE.

Shell brightly colored and polished and elongate, with a short spire
sometimes more or less covered by a callous deposit, and a very large
lower whorl which makes up the greater part
of the shell; aperture long and narrow; oper-
culum often wanting : about 250 species, mostly
subtropical.

1. OLIVA Bruguiere. Shell almost cylindric-
al; columella with folds; no operculum; foot
large, partly enveloping the shell: 150 species.

O. litterata Lamarck (Fig. 882). Shell
slender, tapering towards both ends, 6 cm.
long, whitish in color, with spiral bands of
brown markings; aperture lined with violet:
North Carolina to Key West; West Indies;
on sandy beaches.

2. OLIVELLA Swainson. Shell small; spire taller than in Oliva;
suture caniculated; operculum present; tentacles and eyes absent: 31
species.

0. mutica (Say). Rice shell (Fig. 883). Shell fusi-
form, 12 mm. long; color whitish, with wavy brown bands
on the lower whorl; aperture half the length of the
shell: North Carolina to Florida; West Indies; on sandy
beaches.

3. HARPA Lamarck. Harp shell. Shell large, with
a large, bulging lower whorl and with prominent longi-
tudinal ribs; foot large; radula absent in the adult; aperture large; no
operculum : 9 species, in tropical seas, but not in the Atlantic.

Fig. 881 — Hitra swainsoni

(Dall). Fig. 882 — Oliva

litterata (Rogers).

Fig. 883

Olivella

mutica

(Rogers).

GASTROPODA 561

H. ventricosa Lam. (Fig. 884). Length 12 cm.; color brownish,
with square spots of purple forming broad spiral bands on the whorls;
between the ribs are scallops of light and dark
brown: Indian Ocean; often used as an ornament.

DIVISION 5. TOXOGLOSSA.

Radula long and narrow, with 2 rows of long
teeth, which are the marginals, the centrals and lat-
erals being absent; proboscis with a poison gland;
siphon distinct ; aperture either notched below or pro-
longed to form a siphonal canal ; shell spiral : 4 fami-
lies, all marine, and mostly carnivorous, the animals

feeding largely on mollusks which they kill by means Fig. 884

Harpa ventricosa

01 their long teeth and the poison. (Rogers).

Key to the families of Toxoglossa:

ot Shell a reversed cone 2. CONIDAE

02 Shell not a reversed cone.
6X Shell with a tall spire.

Cj Aperture ending below with a notch 1. TEREBBIDAE

c2 Aperture channelled below notched above 3. PLEUBOTOMIDAE

62 Shell more or less ovate 4. CANCELLABIIDAE

FAMILY 1. TEREBRIDAE.

Shell elongate, with a very tall acute spire and with flattened
whorls; aperture small, with a deep notch below; operculum horny;
tentacles short, wide apart, with eyes at their tips or wanting: 1 genus.

TEREBRA Lamarck. With the characters of the family : 200 species,
mostly tropical.

T. dislocata Say. Shell 44 mm. long, 8 mm. wide; color brownish
or yellowish, with a pale revolving band and numerous minute revolving
lines; whorls 13, with 15 to 18 ribs on each and numerous minute revolv-
ing grooves: Maryland to Texas and in the West Indies; in shallow
water.

FAMILY 2. CONIDAE.

Shell thick, conical, with a low, flattened spire and a very large
lower whorl which tapers towards the lower end; surface often smooth
and brightly colored; aperture long and narrow; operculum present or
absent ; proboscis long ; siphon short and thick : numerous species, mostly
tropical, many very beautiful.

CONUS L. With the characters of the family: 300 species.

C. calif ornicus Hinds. Spire without protuberances; color of shell
white, of periostracum chestnut; latter sometimes hirsute; length 25
mm.: California, towards the south.

562 MOLLUSCA

C. floridanus Gabb. Spire rather high; color yellowish, streaked
with broken lines of brown spots; length 5 cm.: Cape Hatteras to
Florida.

0. mannoratus L. (Fig. 885). Spire low; color dark brown, with
large triangular white spots ; length 12 cm. : Indian and Pacific Oceans ;
common in collections.

FAMILY 3. PLEUROTOMIDAE.

Shell elongate, with a tall spire; lower whorl prolonged to form a
long canal; aperture narrow and long; outer lip thin, with a notch near

Fig. 885 Fig. 886 Fig. 887

Fig. 885 — Conus marmoratus (Rogers). Fig. 886 — Bela harpularia (Verrill).
Fig. 887 — Cancellaria reticulata (Rogers).

the upper end; operculum horny, sometimes absent; eyes at the base
of the tentacles ; siphon long : 650 species ; cosmopolitan ; mostly in deep
water and towards the south.

BELA Leach. Shell fusiform and thin; canal short; notch of outer
lip small or wanting; operculum pointed at both ends; aperture short:
northerly in distribution.

B. harpularia (Couthouy) (Fig. 886). Shell with 6 or 8 whorls,
which have a shoulder just beneath the suture; brownish-pink in color
and with rounded longitudinal ribs which are crossed by fine revolving
lines ; length 16 mm. ; width 8 mm. : Long Island Sound to Nova Scotia,
in rather deep water.

FAMILY 4. CANCELLARIIDAE.

Shell ovate or elongate, with longitudinal and revolving ridges and
grooves; aperture elongate, prolonged below to form a siphonal canal;
columella with spiral folds; outer lip ribbed within; no operculum: 80
species.

CANCELLARIA Lamarck. Shell cancellated, reticulated or ribbed;
columella with prominent folds; canal rather short; outer lip bulging:
70 species, in warm seas.

FELECTPODA

563

C. reticulata (L.) (Fig. 887) . Shell 5.5 cm. long and banded with yel-
low, white, and brown : Cape Hatteras to west Florida, in shallow water.

CLASS 4. PELECYPODA.* (LAMELLIBRANCHIATA.)

Symmetrical mollusks with a double or bivalve shell and mantle,
and without a head (Fig. 740, C).

External Structure.— The compact visceral mass is compressed later-
ally and the two lobes of the mantle extending downwards from the
back entirely enclose both it and the foot. When the animal moves
about the foot is extended between the edges of the mantle (Fig. 888, 1).
The hinder part of the mantle lobes controls the inflow and the outflow
of water between the
mantle cavity and the out- A

side. In some of the more
primitive bivalves, espe-
cially such as are sessile,
as the oyster, this func-
tion is but little localized,
a current flowing out of
the mantle cavity in the
region of the anus and one
flowing into it at other
portions of its hinder and
lower borders (Fig. 888).
In most bivalves, how-
ever, the hinder margins
of the mantle are highly
modified, and are closely

applied to each other, leaving two openings which are called siphons;
through the lowermost of these, which is called the branchial or
incurrent siphon, water flows into the mantle cavity, bringing the
microscopic food of the animal and the air needed for respiration, and
through the uppermost, which is called the cloacal or excurrent siphon,
it flows out, conveying the exhausted respiratory water with the excre-
ment and often the genital products. In very many pelecypods the
posterior mantle edges forming the siphons are not merely applied to
each other but are fused together and extended in the form of tubes.
Fusion has also taken place to a greater or less extent along the entire
edge of the mantle in the higher bivalves, a small slit only being left
for the foot (Fig. 888).

* See "The Mollusca of the Chicago Area ; The Pclecypoda," by F. C. Baker,
The Natural History Survey, Bull. No. Ill, Pt. 1, 1898.

Fig. 888 — Diagrams showing the formation of the
siphons, the anterior end in each figure being
towards the left and the dorsal side being above.
A, mantle open and no definite siphons ; B, mantle
open and incomplete siphons ; C, cloacal siphon
complete ; D, both siphons complete but not ex-
tended ; E, siphons extended and mantles joined
ventrally ; F, mantles completely joined, leaving a
narrow space for the foot and one for the byssus
(Lang). 1, foot; 2, left-hand mantle; 3, right-
hand mantle ; 4, cloacal siphon ; 5, branchial
siphon ; 6, byssus opening.

564 MOLLUSCA

The shell, like the mantle, consists of two parts or valves, which
are joined together dorsally and open ventrally to permit the edges of
the mantle, the siphons, and the foot to be protruded. The shell is
invariably present, but may be rudimentary; the two valves are not
always symmetrical, and vary much in thickness in the different species.
The outer layer or periostracum is thin and non-calcareous and is often
wanting. The inner or mother-of-pearl layer shows a play of colors in
many species, due to the refraction of light by the delicate horizontal
plates of which it is composed, which often gives the shell commercial
value. Pearls are cysts of mother of pearl which have formed around
foreign objects, usually larval trematode worms, which have lodged
between the mantle and the shell. The middle or columnar layer is usu-
ally thick. The mother-of-pearl layer is de-
posited by the general surface of the mantle.
The other two layers are formed by its margin,
and hence show concentric lines of growth.
These lines are grouped around the umbo or
beak at the dorsal margin of the shell, which
is the oldest part of it, and often prominent,
and often projects forwards. In front of it
is, in certain bivalves, a heart-shaped de-

PreSSed area Called the ?Unule <Fi&' 889>4)-
The tw° ValveS °f the she11 are held
^ a m°re °r leSS elastic band Called the

ment (2)» which is usua11^ external and con-

sists °f tw° distinct Parts> the outer Portion

10, pallial sinus. or cartilage, the latter being very elastic and

composed of parallel fibers.

Beneath the umbo is the hinge, which is usually composed of inter-
locking teeth in the two valves. These teeth are distinguished as cardi-
nals and laterals, the former (7) being immediately beneath the umbo;
the latter often consist of long ridges and are called the posterior lat-
erals (8) when they are behind, and the anterior laterals (6) when in
front of the umbo. The inner surface of each valve shows, often promi-
nently, a number of impressions caused by the attachment of muscles in
the shell. These are the adductor muscle impressions (1 and 5), of
which there are either one or two, the much smaller impressions of the
siphonal and pedal retractor muscles, and the pallial line (9). The lat-
ter is a broad line which connects the anterior and posterior adductor
impressions and represents the points where the numerous retractor
muscles of the margin of the mantle are inserted; it is often indistinct.

PELECYPODA

665

The siphonal muscle impression is present only in shells possessing elon-
gated, retractile siphons, and is situated beneath or behind the posterior
adductor impression, where it forms a more or less prominent forward
bend or angle in the pallial line, which is called the pallial sinus (10).

The two valves of the shell are closed by the two powerful adductor
muscles above mentioned, which are attached to their inner surface; in
a large number of pelecypods but one muscle is present, the anterior
adductor being wanting. When the adductors are relaxed the elasticity
of the hinge ligament causes the shell to open. Other muscles which
are attached to the shell extend the foot and the siphons.

The mantle cavity contains the ctenidia or gills, which are usually
plate-like structures attached along their dorsal margins, two gills lying
usually on each side (Fig. 890, C). In the simplest pelecypods (Fig.
890, A), however, a pair of bipinnate ctenidia similar to those of gas-
tropods is present. At the forward end of the visceral mass in the
median line is the mouth
(Fig. 740, C). It is with-
out jaws or radula, and
on each side of it are two
ciliated flaps called oral
palps (Fig. 904), the cilia
of which cause small food
particles, more or less
immersed in mucus, to
pass into the mouth. The
anus is at the hinder end and opens into the dorsal or cloacal portion
of the mantle cavity. The foot is wanting in some pelecypods, but in
most of them it is a wedge or tongue-shaped structure ; the most primi-
tive forms have a disc-like sole like the gastropods. Very many pelecy-
pods secrete a tough, stringy substance from a gland in the foot called
the byssus (Fig. 898, 5), by means of which they attach themselves to
stationary objects, becoming thus fixed in one place. In many forms
which are without it as adults, the byssus is present in the larva. Many
bivalves attach themselves permanently by cementing one of the valves
to some other object or by boring cavities into clay, rock, or wood, from
which they cannot escape.

Internal Structure (Fig. 904). — The mouth is without salivary glands
and is joined by a short oesophagus with the large stomach. Surround-
ing this organ is the voluminous liver. The intestine (Fig. 740, C) is a
long tube which winds about in the visceral mass, to the dorsal side of
which it finally ascends, where it passes backwards through the ventricle
of the heart (except in the oyster, and certain others) to the anus. At

Fig. 890 — Diagrams of pelecypod gills. A, Proto-
tranchiatd; B, Filibranchiata ; C, Eulamellibran^
chiata; D, Septibranchiata (Lang). 1, mantle;
2, visceral mass ; 3, ascending lamella of gill ; 4,
descending lamella of gill.

566 MOLLUSCA

the forward end of the intestine is usually a tubular pocket, which opens
into the stomach in some forms, containing a crystalline rod of unknown
function. The heart consists of a muscular ventricle and a pair of
auricles which receive the blood which has just passed through the gills.
The kidneys are paired, each opening into the pericardium and also
into the mantle cavity. Additional excretory glands are the organs
of Keber, which are a pair of glandular organs arising either from
the walls of the auricle or the pericardium; they are wanting in
the Protobranchiata. Three pairs of widely separated nerve ganglia
characterize most bivalves, the cerebral ganglia, just above the mouth,
the pedal ganglia in the foot, and the visceral ganglia at the hinder end
of the visceral mass; the cerebral ganglia are joined with each of the
other pair by a pair of connectives.

In correlation with their sluggish habits, the special sense organs
of the bivalves are poorly developed. A pair of osphradia, which are
supposed to be olfactory organs, are present at the base of the gills near
the posterior adductor muscle. Tactile cells are often present, especially
upon the siphons and the edge of the mantle. Eyes are usually absent
but are present in a number of forms. Pecten possesses highly developed
eyes, which are on projections at the edge of the mantle. Area has com-
pound eyes, similar to those of arthropods. A pair of lithocysts occurs
in the foot.

The gonads are branched organs which open into the mantle cavity
at the base of the gills. In the Protobranchiata and certain other primi-
tive forms the gonads open into the kidneys, but in most bivalves dis-
tinct genital ducts are present. The sexes are usually separate, but
hermaphroditism is riot uncommon. Ova and sperm are extruded into
the water, where fertilization takes place. Special egg capsules are
not formed ; in the Unionidae, however, the eggs are taken into the water
tubes usually of the outer and in the Cyrenidae into those of the inner
gills, where they are protected until they hatch.

Distribution and Habits. — Pelecypods are all aquatic, and mostly
marine animals which live in great part in shallow water along the mar-
gins of the continents. They vary in size between the gigantic Tridacna
gigas of the Pacific Ocean, the shells of which may be a meter and more
long and weigh 250 kilograms, and the minute fresh water Pisidium or
Spharium, which may measure only a few millimeters in length. Most
of them creep slowly about on the wedge-shaped foot, some can spring
(Cardium), while some move by squirting water from the siphons
(Ensis). Pecten swims rapidly by clapping the shells together. The
food consists of minute animals and plants, which are drawn into the
mouth by the cilia of the oral palps. Very many bury themselves in

PELECTPODA 567

the sand or mud or bore into clay, wood, or rock, with only the tips of
the siphons extending into the water, and are then protected from their
enemies. Others protect themselves from predacious fish by fastening
themselves to some other object by means of their byssus, or cementing
the shell to a rock or stone.

Bivalves are useful to man in a variety of ways. Many are impor-
tant articles of food, the oyster and clam being raised artificially for
this purpose. The shells of numerous species, especially the large fresh-
water mussels, are used for making buttons and other things, and pearls
are probably the most valuable single objects obtained from any animal
whatsoever.

History. — The term bivalve was employed by Linna3us, in whose
system of classification the Bivalvia were a subdivision of the Testaeea,
one of the four divisions of Vermes. Cuvier called the group the Aceph-
dla, and included in it, besides the bivalves, tunicates, brachiopods,
and cirripeds. Blainville named bivalves the Lamellibranchiata (1816),
a name which has had the greatest vogue of any of the numerous names
given to this group, down almost to the present time. In 1818 Lamarck
called them the Conchifera, and in 1821 Goldfuss, the Pelecypoda. The
latter name was revived by Tryon (1884) and Fischer (1885), and has in
the past few years almost entirely supplanted the others.

The main subdivisions of the class, in the older books, were usually
based upon the presence and form of the siphons or the adductor muscles,
but at the present time the system proposed by Pelseneer (1888), the
basis of which is the structure of the gills, is universally adopted.

The Pelecypoda contain about 11,000 species grouped in 5 orders,
of which a fifth inhabit fresh water; about 15,000 fossil species are known.

Key to the orders of Pelecypoda:

at Gills not lamellar but pinnate (Fig. 890, A), and in the hinder part of the
mantle cavity ; foot with a creeping surface ; pallial sinus present or
absent (Fig. 889, 10) 1. PEOTOBBANCHIATA

fl2 Gills composed of rows of parallel filaments (Fig. 890, B) ; no pallial

sinus ; byssus well developed 2. FILIBBANCHIATA

«s Gill filaments joined together ; no pallial sinus ; but one muscle.

3. PSEUDOLAMELLIBRANCHIATA

a4 Gill filaments completely joined, forming a continuous surface (Fig.
890, C) ; pallial sinus usually present (Fig. 889, 10) ; most
pelecypods 4. EULAMELLIBBANCHIATA

o5 Gills absent ; pallial sinus present 5. SEPTIBBANCHIATA

ORDER 1. PROTOBRANCHIATA.

Gills (Fig. 890, A) consisting on each side of an axis, to which are
attached 2 rows of short, flat leaflets projecting backwards freely into the
mantle cavity ; foot more or less of a flat creeping sole often surrounded

568 MOLLUSCA

by a fringed margin ; gonads open into the kidneys ; 2 adductor muscles ;
mantle either open below or closed; siphons either absent or present: 2
families, both marine.

Key to the families of Protobranchiata:

CK Hinge with teeth 1. NUCULIDAE

a, Hinge toothless 2. SOLEMYIDAE

FAMILY 1. NUCULIDAE.

Shell equivalve, oval or triangular, pearly within; hinge with great
numbers of saw-like teeth, interrupted by a central pit for the ligament,
which is either external or internal; mantle open below; no byssus; oral
palps very large, with a posterior appendage: about 40 species on the
Atlantic coast, mostly in deep water.

Key to the genera of Nuculidae here described:

ttj No siphons; hinder part of the shell not prolonged and without pallial

sinus 1. NUCULA

aa Siphons and pallial sinus present ; hinder part of shell prolonged.

&! Pallial sinus large 2. YOLDIA

&, Pallial sinus small 3. LEDA

1. NTTCULA Lamarck. Shell oval, somewhat
triangular, with a short posterior side; periostra-
cum olive; foot used for burrowing: 70 species,
Fig. 891 Fig. 892 cosmopolitan.
Fig. 891— Nucuia N. proxima (Say) (Fig. 891). Shell strongly

proximo, (Verrill). J' V

Fig. 892 — Nucuia oblique, thick; umbo prominent; hinge teeth large,

rill). 12 behind and 18 before the umbo, the two series

of teeth forming nearly a right angle; length 10
mm.; height 9 mm.; width 6 mm.: South Carolina to Gulf of St. Law-
rence; often common in shallow water.

N. delphinodonta* Mighels (Fig. 892). Shell ovate, somewhat
oblique; hinge teeth, 3 behind and 7 before the umbo; length 3.2 mm.,
height 2.7 mm.; width 2.2 mm.: New Jersey to Greenland, in 6 to 100
fathoms; often abundant; Europe.

2. YOLDIA Holier. Shell elongate, compressed, smooth, and shining,
attenuated and gaping behind, dark olive in color; mantle open, with
elongated, united, retractile siphons; animal very active, leaping
through the water: about 12 species on the Atlantic coast.

Y. limatulaf (Say) (Fig. 893). Shell 48 mm. long, 23 mm. high,
and 13 mm. wide; umbo near the center, the posterior dorsal slope

* See "Life History of Nucuia delphinodonta," by G. A. Drew, Quart. J. M. S.,
Vol. 44, New Ser., 1901.

t See "Yoldia limatula," by G. A. Drew, Mem. Biol. Lab., Johns Hopkins,
Vol. 4, 18S9.

PELECYPODA 569

straight; teeth prominent, 23 on anterior and 18 on posterior side:
North Carolina to Labrador in shallow water; common; Pacific coast;
Europe.

Y. sapotilla (Gould). Like the above but much smaller, and with
about 16 teeth on each side ; 22 mm. long, 11 mm. high and 7 mm. wide :
Long Island to Arctic Ocean ; often common, in 4 to 120 fathoms.

Y. thraciaeformis Storer. Shell reniform, rounded and broadest
behind, gaping at both ends; 5 cm. long; 4 cm. high, and 27 mm. wide;
hinge with about 12 teeth on each side: Long Island to Arctic Ocean;
in rather deep water.

3. LEDA Schumacher. Shell elongated, the hinder part being much
prolonged; mantle open, with small, united siphons: 80 species, cosmo-
politan.

L. tenuisulcata (Couthouy) (Fig. 894). Shell 25 mm. long, 12 mm.
high, and 7.5 mm. wide, light greenish-yellow in color, with 12 anterior

Fig. 893 Fig. 894 Fig. 895

Fig. 893 — Yoldia limatula (Verrill). Fig. 894 — JLeda tenuisulcata (Gould).
Fig. 895 — Solemya, velum (Verrill).

and 16 posterior teeth: Rhode Island northwards, in shallow water;
often common.

FAMILY 2. SOLEMYIDAE.

Shell equivalve, elongate, cylindrical, gaping at each end; perios-
tracum thick, extending over the edge of the shell; hinge toothless; foot
long and slender; oral palps elongate; mantle fused below, leaving an
opening for the foot and one hourglass-shaped siphonal opening behind :
1 genus.

SOLEMYA* Lamarck (Solenomya Menke). With characters of the
family: several species.

S. velum Say (Fig. 895). Shell very thin and fragile, yellowish-
brown in color, with about 15 impressed lines radiating from the umbo
to the margin, bluish-white within, 25 mm. long, 12 mm. high, and 8 mm.
wide: North Carolina to Nova Scotia; usually buried in the sand; also
found swimming backwards and forwards; often common.

S. borealis Totten. Like the above but much larger and darker;
length 5 cm. ; height 22 mm. ; width 14 mm. : Long Island Sound to Nova
Scotia; rare.

* See "Locomotion in Solenomya," etc., by G. A. Drew, Anat. Anz., Vol. 17, 1900.

570 MOLLUSCA

ORDER 2. FILIBRANCHIATA.

Gills consisting on each side of an axis, to which are attached 2
rows of very long, filamentous leaflets (Fig. 890, B), which hang down
far into the mantle cavity, each row being recurved and bent upwards,
so that each leaflet has a descending and an ascending limb, which are
not joined by interlamellar partitions, except in the Mytilidae; genital
and kidney pores separate (except in the Anomiidae) ; foot usually weak,
with well developed byssus; 2 adductor muscles; mantle open below;
siphons absent or little developed: 4 families, all marine.

Key to the families of Filibranchiata here described:

ot Shell not equivalve, animal attached ........................ 1. ANOMIIDAE

a, Valves of shell alike.
&! Not attached by byssus .................................... 2. ABCIDAE

6a Attached by byssus ..................................... 3. MYTILIDAE

FAMILY 1. ANOMIIDAE.

Shell thin, with asymmetrical valves, the right valve being undermost
and provided with a deep notch or a hole, through which a calcified
byssus projects, fastening the animal to a rock or
a shell; oral palps wanting; posterior adductor the
larger ; mantle fringed, with short cirri ; no siphons ;
foot cylindrical, expanded and grooved at the end;
sexes separate: 4 genera.
Anon^agephiPPium ANOMIA L. Right valve flat ; left valve convex :

1, ivarve- 2 40 SPecieS-

right valve; 3, notch. A. ephippium L. (A. simplex D'Orbigny).

Jingle shells (Fig. 896). Shell variable in shape,
circular or oval in outline, about 25 mm. in diameter, or larger; outer
surface scaly and dark colored, but in dead shells often worn off, ex-
posing the glistening greenish or golden mother of pearl: Nova Scotia
to Texas; West Indies; in shallow water, abundant on oyster beds;
Europe, where it is used for food.

A. aculeata Gmelin. Shell 12 mm. in diameter, covered with scaly
or prickly radiating lines on upper valve: Long Island to the Arctic
Ocean; Europe; in shallow water; common north of Cape Cod.

FAMILY 2. ABCIDAE.

Shell oval, symmetrical, with a heavy periostracum, and usually
with the radial corrugations ; hinge with a row of similar comb-like teeth ;
mantle open below ; foot large, bent, and grooved ; both adductors large ;
no siphons: several hundred species; cosmopolitan.

PELECYPODA 571

ARCA L. Blood clams. Shell equivalve, or nearly so, thick; umbo
anterior; foot pointed, with a byssus; edges of mantle with numerous
compound eyes: 140 species.

A. noae L. Noah's arch. Shell elongated, wide, angular, almost
quadrangular; uinbo prominent, the two being far apart; valves gaping
below, with radial ribs; length 10 cm.: Cape Hatteras, southwards, in
shallow water ; West Indies ; Pacific coast ; Medi-
terranean Sea.

A. pexata Say (Fig. 897). Shell thick, oblong,
with prominent umbo directed very obliquely for-
wards, and with about 32 to 36 radiating ribs, 56
mm. long, 53 mm. high and 37 mm. wide ; periostra-
cum thick and shaggy and dark brown in color: Fig 897

Maine to Florida, often common on the bottom in Arca Pexa'ta <Gould>-
shallow water, or attached by the byssus.

A. transversa Say. Shell rhomboidal, the umbo not directed so
obliquely forwards as in A. pexata, with 32 to 36 ribs; color brown;
length 37 mm.; height 25 mm.; width 37 mm.: Cape Cod to Florida, in
shallow water.

FAMILY 3. MYTILIDAE.

Mussels. Shell elongate, equivalve, with umbo at or near anterior
end; hinge usually toothless; foot cylindrical and grooved, with byssus;
anterior adductor small, posterior large ; distinct cloaeal but no branchial
siphon: several hundred species.

Key to the genera of Mytilidae here described:

ot Animals not boring.

&x Umbo at extreme anterior end 1. MYTILUS

6, Umbo not quite at anterior end.
ct Length 25 mm. or over.

dt Two striated areas not present 2. MODIOLUS

d3 Two distinct striated areas 3. MODIOLARIA

ca 12 mm. long 4. CRENELLA

a. Boring animals 5. LITHOPHAGUS

1. MYTILUS L. Shell wedge-shaped, being pointed in front and
round behind, smooth; umbo at anterior end: 65 species; cosmo-
politan.

M. edulis L. (Fig. 898). Edible mussel. Color of periostracum
black or dark brown, within pearly with violet margins; length 10 cm.;
height 35 mm.; width 25 mm.: circumpolar, south to North Carolina
and San Francisco; Europe; very common, attached to rocks and to
each other; between tide lines and in shallow water; used for food in
Europe.

572

MOLLUSCA

2. MODIOLTJS Lamarck. Horse nmssels. Shell wedge-shaped, in-
flated in front; umbo not quite at front end: 70 species; cosmopolitan;

the animals burrow in the
sand and gravel, and differ in
this respect from Mytilus.

M. modiolus (L.) (Fig.
899) . Periostracum thick,
coarse in texture, dark brown
in color; interior pearly;
length up to 15 cm., but usu-
ally under 4 cm. ; usual height
2 cm. ; width 45 mm. : circum-
polar, south to New Jersey
and San Francisco; Europe;
common in deep water, among

I.

Pig. 898— Mytilus edulis (Lang),
umbo ; 3, cloacal siphon ; 4, mantle

1, foot; 2,

5, byssus.

rocks and gravel.

M. demissus Dillwyn. Shell elongate; surface marked by numerous
impressed radiating ribs; color greenish-yellow; pearly within, tinted
with purple ; length 75 mm. ; height 30 mm. ; width 23 mm. : Georgia to
Nova Scotia; very common on mud flats; also at San Francisco.

3. MODIOLARIA Gray. Shell elliptical, front end blunt; surface
with two areas of fine radial striations, one anterior and one posterior,
between which there are no striations ; cloacal siphon long : many species.

Fig. 899 Fig. 900

Fig. 899— Modiola modiolus (Verrill). Fig. 900— Modiolaria nigra (Verrill).

M. nigra (Gray) (Fig. 900). Shell 5 cm. long, 28 mm. high, and 15
mm. wide; brown in color; anterior striated area small in extent: cir-
cumpolar, south to Long Island, in shallow water; Europe.

M. discors (L.). Shell oval, 25 mm. long, 16 mm. high, 10 mm.
wide, dark greenish in color; anterior area with 16 striations: circum-
polar, south to Long Island and Puget Sound, from low water to 500
fathoms; common north of Cape Cod; Europe.

4. CRENELLA Brown. Shell small, oval or rhomboidal, with numer-
ous radiating striations or ribs; hinge with a tooth in each valve; foot
with a disc at end; byssus a single thread; umbo near anterior end:
about 5 species on the Atlantic coast.

PELECTPODA

573

Fig. 901
Crenella
glandula
(Verrill).

C. glandula (Totten) (Fig. 901). Shell 12 mm. long, 9 mm. high,
7 mm. wide, brownish-yellow in color: New Jersey to Gulf of St. Law-
rence, in shallow water.

5. LITHOPHAGTTS Bolten (Lithodomus Cuvier) . Shell cy-
lindrical, inflated, rounded in front, wedge-shaped behind :
4 species on the South Atlantic and 1 on the Pacific coast.

L. lithophagus (L.) (Fig.
902). Shell elongate, 3 to 8
cm, long, with fine longitu-
dinal and transverse lines: Florida; West
Indies; Europe; it attaches itself to a
rock by its byssus when young, into which
it bores when adult, forming a hole the
shape of the shell. It made the holes in
the columns of the Temple of Serapis
at Puzzuoli in Italy, which are used as
proofs of the oscillations of the coast in
that region.

Fig. 902

us lithophagus
(Rogers).

ORDER 3. PSEUDOLAMELLIBRANCHIATA.

The consecutive filamentous leaflets of each row of the gills are
more or less connected, and the two limbs of each leaflet are joined
by interfilamentary partitions (Fig. 890, C) ; the ascending limb also of
the outer leaflet is united with the mantle, except in Pectinidae; foot
weak or absent ; genital and kidney pores distinct except in the Pectinidae;
but 1 adductor muscle, the anterior usually being very small or absent;
mantle entirely open, with no siphons : 4 families, all marine.

Key to the families of Pseudolamellibranchiata here described:

«! Two adductor muscles, the anterior one very small 1. AVICULIDAE

cra But one adductor muscle.

&! Shell irregular ; oysters 2. OSTREIDAE

62 Shell regular ; scallops 3. PECTINIDAE

FAMILY 1. AVICULIDAE.

Shell usually with valves of unequal size, the right valve being
smaller; animal rests on the right valve and is attached by its byssus:
numerous species, in tropical and temperate seas; about 6 species on the
Atlantic coast, all towards the south. The pearl oyster, Meleagrina
margaritifera (L.), which attains a length of 30 cm. and lives in the Indian
Ocean in 6 to 15 fathoms, belongs to this family. A closely allied
species of the same genus in the West Indian waters also furnishes
pearls.

574

MOLLUSCA

PINNA L. Shell equivalve, wedge-shaped, with the pointed end, on
which is the umbo, anterior in position ; posterior end broad and gaping ;
hinge teeth absent: 30 species, some of which produce black pearls of
considerable value. '

P. muricata L. (Fig. 903). Shell white and semitransparent, with
straight sides with obscure longitudinal ribs, which are covered with
scales; length 17 cm.: North Carolina to Texas.

FAMILY 2. OSTREIDAE.

Oysters. Shell inequivalve, resting on and attached by the left
valve, irregular and variable in shape, very thick, often in folded layers;
foot absent: 1 genus.

OSTREA* L. Shell circular or elongate, upper valve more or less flat
and the lower convex; umbo and hinge at forward end; hermaphroditic
or unisexual; adductor muscle near the middle with the heart just in

Fig. 903

Fig. 904

Fig. 903 — Pinna muricata (Rogers). Fig. 904 — Ostrea virginica — left valve
removed to show organs (Brooks). 1, right valve of shell; 2, mantle; 3, gills;
4, labial palps ; 5, rectractor muscle ; 6, mouth ; 7, intestine ; 8, stomach sur-
rounded by the liver ; 9, anus ; 10, visceral mass ; 11, posterior end of animal ;
12, dorsal side of animal.

front of it; muscle impressive violet or brown; shell white: about 100
species, in all seas except the colder ones ; 1 species on the Atlantic and
1 on the Pacific coast; 500 fossil species.

0. virginica Gmelin (Fig. 904). The American oyster. Length up
to 45 cm., usually about 12 cm. : Gulf of Mexico to Massachusetts, locally
to Gulf of St. Lawrence, in shallow and brackish water, often very
abundant, the most valuable American invertebrate animal; introduced
on the Pacific coast.

* See "The Oyster," by W. K. Brooks, 2nd Ed., 1905. "A Manual of Oyster
Culture," by Caswell Grave, Fourth Rep. Maryl. Shellf. Com., 1912.

PELECTPODA 575

O. lurida Carpenter. The Pacific coast oyster. Diameter 5 cm. or
less; shell thin and purplish: Puget Sound to California.

FAMILY 3. PECTINIDAE.

Scallops. Shell inequivalve, either free or attached, with radial ribs
or striations; foot cylindrical; without siphons: about 7 genera.

PECTEN 0. F. Miiller. Shell consisting of a round body with radi-
ations and 2 wings; hinge line straight and toothless; shell rests on the
right valve, which is the less convex and has a prominent notch, where
the anterior wing joins the body of the shell; muscle near the middle of
the body; gill attached by one lamella only: numerous species. Scal-
lops leap and swim by snapping the shell together, giving them a zigzag
course; they are used for food, the muscle being usually the only part eaten.

Key to the species of Pecten here described :

Oj Valves with about 20 radiating ribs P. IBBADIAIVS

aa Valves with about 50 ribs P. ISLANDICUS

o3 No ribs P. MAGELLANICUS

P. irradians* Lamarck. Common scallop
(Fig. 905). Shell with about 20 radiating ribs
and with numerous lines of growth ; wings large
and equal in size ; color variable, the upper valve
being the darker ; length 75 cm. ; breadth a little
less; 30 to 40 bright blue eyes in the edge of
each mantle : Cape Cod to Texas, locally farther
north ; often abundant among eel grass and over

™vi,q flafc Fig. 905 — Pecten irradians

mud flats. (Verrill).

P. islandicus (Mill.). Shell with over 50

narrow ribs; wings unequal in size, length 9 cm.; width 75 mm.: Cape
Cod to Arctic Ocean; Europe.

P. magellanicusf (Gmelin). Giant scallop. Shell without ribs but
covered with fine radiating striations, 17 cm. long; wings equal in size;
upper valve brown, lower white: New Jersey to Labrador.

ORDER 4. EULAMELLIBRANCHIATA.

Two gills on each side (Fig. 890, C), each of which is composed of
the filamentous leaflets joined by vascular trabeculae (interfilamentary
connections) to form a continuous lamella; each gill composed of 2
lamellae, which are the two limbs of the leaflets joined by interlamellar

* See "Habits and Life History of the Scallop (Pecten irradianft)" by J. Risser,
Ann. Com. Fisb., Rbode Island, 1901.

t See "Habits, etc., of the Giant Scallop," etc., by G. A. Drew, Stud. Univ. of
Maine, No. 6, 1906.

576 MOLLUSCA

partitions, the ascending limb of the outer leaflet being united with the
mantle; genital glands have independent openings to the outside; two
adductor muscles usually present; mantle edges more or less fused and
the siphons present (Fig. 888), either in form of closed tubes or not;
foot usually large, with byssus little or not at all developed: about 27
families, grouped in 7 suborders, including most pelecypods.
Key to the suborders of Eulamellibranchiata :

Oj Mantle often below, shell usually with no pallial sinus. . . .1. SUBMYTILACEA
a, Shell usually thin, with pallial sinus (Fig. 889, 10) ; siphons usually

present.
&! Pallial sinus prominent.

G! Pallial sinus extending far forwards 2. TELLINACEA

ca Pallial sinus not so large.
di Animals do not bore in solid objects.

et Shell thick and solid and more or less round 3. VENERACEA

e2 Shell rather thin and usually elongate 5. MYACEA

d3 Animals bore in clay, wood, or rock G. PHOLADACEA

6, A slight pallial sinus or none present.

<?! Shell thick, usually ribbed 4. CARDIACEA

ca Shell thin 7. ANATINACEA

SUBORDER 1. SUBMYTILACEA.

Mantle edges open below; closed siphons and pallial sinus usually
absent; 2 adductor muscles; cardinal and lateral teeth (Fig. 889) well
developed: about 16 families, in fresh and salt water.

Key to the families of Submytilacea here described:

at Animals marine.
&! Shells not minute, although in some cases small.

Cj_ Shells radially grooved 4 1. CABDITIDAE

c3 Shells not radially grooved.
dj, Umbo not at forward end.
&L Lunule present (Fig. 889, 4).
/! Adductor muscle impressions nearly equal in size.

fft Shell mostly more than 20 mm. long 2. ASTARTIDAE

g2 Shell mostly less than 8 mm. long 3. CRASSATELLIDAE

/2 Anterior muscle impression much the longer 7. LUCINIDAE

€1 Lunule absent 4. CYPRINIDAE

d3 Umbo at forward end 6. DREISSENSIIDAE

6a Shells minute.

ca Ligament external 8. KELLYELLIDAE

ca Ligament internal 9. ERYCINIDAE

aa Animals in fresh water.

&! Shell large 5. UNIONIDAE

63 Shell minute 10. CYRENIDAE

FAMILY 1. CAEDITIDAE.

Shell heart-shaped or ovate, with radiating ribs or striations, hinge
thick, with 1 or 2 cardinal and 1 or 2 lateral teeth; foot with byssus; no
closed siphon: about 10 genera, all marine.

PELECYPODA 577

VENERICARDIA Lamarck. Shell with a rough periostracum ; hinge
with 2 large oblique cardinal teeth and 1 lateral in each valve; ligament
external: several species on the Atlantic coast.

V. borealis (Conrad) (Fig. 906). Shell with about 20 rounded ribs;
umbo elevated and turned forwards, almost to the anterior end in old
shells; length 25 mm.; height and width 17 mm.: New Jersey to Lab-
rador; in rather deep water; Pacific coast.

FAMILY 2. ASTABTIDAE.

Shell thick, equivalve, with 2 or 3 strong cardinal teeth in each
valve ; ligament external ; laterals absent or rudimentary ; lunule distinct ;
a short cloacal siphon present: about
12 genera, all marine.

ASTARTE Sowerby. Shell roundly
oval, with a smooth surface marked
with concentric striations: 20 species,
circumpolar.

A. castenea (Say) (Fig. 907). Fig. 906 Fig. 907

Chestnut shell. Shell thick, ovate; Fig. 906 — Venericaudia borealis

(Gould). Fig. 907—Astarte casta-
umbo elevated and nearly central; an- nea (Gould).

terior end slightly concave, posterior

slightly convex ; color chestnut ; length and height 25 mm. ; width 13 mm. :

New Jersey to Nova Scotia; in shallow water; often common.

A. undata Gould. Like the above, with 10 to 20 strongly developed
concentric ridges; color brownish-olive; length 25 mm.; height 27 mm.;
width 14 mm. : Long Island Sound to Gulf of St. Lawrence, in shallow
water; common; Pacific coast.

A. quadrans Gould. Shell triangular, smooth, yellowish in color;
umbo central ; length 11 mm. ; height 10 mm. ; width 5 mm. : Long Island
Sound to Gulf of St. Lawrence.

FAMILY 3. CRASSATELLITIDAE.

Shell thick, equivalve, more or less triangular; umbo towards the
forward end, usually concentrally striated; hinge with 1 or 2 cardinal
teeth; lunule distinct; ligament internal; no closed
siphons: about 6 genera, all marine.

CRASSATELLITES Kriiger. Umbo nearly central, an-
Crassafeila terior dorsal line straight ; 2 cardinal teeth in right valve,
^GtouHO? and * in the left; ! lateral in each: 1 species on the

Atlantic coast.

C. mactracea (Linsley) (Fig. 908). Shell small, solid, with about 14
concentric ribs on the surface; color yellowish-green; 6 mm. long and

578

MOLLUSCA

2.5 mm. wide: Cape Cod to Texas; common in shallow water; West
Indies.

FAMILY 4. CYPRINIDAE.

Shell regular, equivalve, more or
less oval, thick, with a thick periostra-
cum; ligament external; pallial line sin-
uous; both siphons complete: numerous
species.

CYPEINA Lamarck. Umbo nearly
central, directed towards the forward
end ; hinge with 3 diverging cardinal teeth
and a posterior lateral in each valve ; foot
thick: 1 species on the Atlantic coast.

C. islandica (L.) (Fig. 909). Shell
thick, coarsely wrinkled, 80 mm. long, 75 mm. high, and 45 mm. wide,
dark colored : Long Island to the Arctic Ocean, in rather deep water, but
often thrown UD on the beach; Europe.

Fig. 909 — Cyprina islandica
(Gould).

FAMILY 5. UNIONIDAE.* (NAIADES.)

Fresh-water clams or mussels. Shell equivalve, with a thick pearly
layer and a dark-colored periostracum ; umbo towards the anterior end;
ligament external and ^

prominent; hinge teeth jtt

consisting of cardinals and
posterior laterals (Fig.
910), present or not; anal
siphon complete but very
short; foot large, with
byssus only in the young:
cosmopolitan; about 1,000
species, of which over 500
occur in this country, all
living in fresh-water
streams and ponds; some
are used for food, and the

Fi

ig.
eol

910 — Diagram of the left valve of Lampsilis
luteolus (Baker). 1, posterior adductor muscle
scar ; 2, posterior foot retractor muscle scar ; 3,
posterior lateral teeth ; 4, ligament ; 5, umbo ;
6, lunule ; 7, anterior adductor muscle scar ; 8.
cardinal teeth ; 9, anterior foot retractor muscle
scar ; 10, pallial line.

* See "Observations on the Genus Unio with Descriptions of New Species," by
I. Lea, 13 vols., Philadelphia, 1834-1874. "Synopsis of the Naiades or Pearly Fresh-
water Mussels," by C. T. Simpson, Proc. U. S. Nat. Mus., Vol. 22, p. 501, 1900. "A
Preliminary List of the Unionidae of West. Penn.," etc., by A. E. Ortmann, Ann.
Cam. Mus., Vol. 5, 1909. "Notes upon the Families and Genera of the Naiades,"
byname, same jour., Vol. 8, 1912. "Notes on the Unionidae and Their Classification,"
by V. Sterki, Am. Nat., Vol. 37, p. 103, 1903. "Studies on the Reproduction and
Artificial Propagation of Fresh-water Mussels," by G, Lefevre and W, C, Curtis, Bull.
Bur. Fish., Vol. 30, p. 105, 1912.

PELECTPODA 579

shells of many of the thick-shelled species are manufactured into buttons.
The eggs are carried usually in the outer pair of gills until the young
larvae, which are called glochidia, are hatched. These attach them-
selves, except in Strophitus, to the skin of fishes, in which they become
encysted, and there complete their development.

Key to the genera of Unionidae here described:

«! Hinge teeth (Fig. 910) well developed; shell usually thick.
6j «hell with distinct rays radiating from the umbo (Fig. 911) . .1. LAMPSILIS
6, No distinct rays.

cx Shell elongate 6. UNIO

c. Shell quadrate 8. QUADRULA

a, Hinge teeth absent or rudimentary ; shell thin.
&! Teeth absent.

G! Hinge line not incurved in front of umbo 3. ANODONTA

ca Hinge line incurved 7. ANODONTOIDES

Z>, Teeth incomplete or rudimentary.

Cj Shell elongate, reniform 5. MARGABITANA

ca Shell rhomboid or round.

</! Teeth rudimentary 2. STROPHITUS

d. Cardinals present, laterals blurred 4. ALASMIDONTA

1. LAMPSILIS Rafinesque. Shell oval or elliptical, usually thick,
with a hard, bright, usually rayed periostracum ; hinge with 2 cardinals
(Fig. 910, 8) and 2 (posterior) laterals in the left and usually 1 of each
in the right valve; male and female sexually dimorphic, the female shell
being swollen at the base just behind the middle: 128 species, all
American.

Key to the species of Lampsilis here described:

a^ Length not twice the height.
&! Length one-third greater than the height.
Cj Cardinals strong and prominent.
dt Shell compressed.

d Umbo and rays prominent L. RADIATA

e2 Umbo and rays not prominent L. LIGAMENTINA

d2 Shell very wide L. VENTRICOSA

c, Cardinals weak L. GRACILIS

ft. Length nearly twice the height.

ct Shell large and thick L. LUTEOLA

Cj Shell small and compressed L. IRIS

a. Length about 21/£ times the height.

&! Color black L. RECTA

&a Color yellow L. ANODONTOIDES

L. radiata (Gmelin) (Fig. 911). Shell ovate, somewhat angular
posteriorly, umbo at the anterior fourth; surface with numerous rays of
dusky green; length 75 mm.; height 42 mm.; breadth 30 mm.: Atlantic
slope, south to North Carolina; northerly to St. Lawrence slope; west
to Manitoba; common.

580

MOLLUSCA

Fig. 911 — Lampsilis radiata
(Gould).

L. ventricosa (Barnes). Pocket-book clam. Shell swollen, ovate,
thick and heavy, rounded before and behind, 15 cm. long, 9 cm. high and

6 cm. wide: valleys of Mississippi and St.
Lawrence, in large streams and lakes; com-
mon; used in button-making.

L. gracilis (Barnes). Shell elliptical,
compressed, round in front, rounded and
very broad behind, 12 cm. long, 7 cm. high,
4 cm. wide; color yellow with green rays
extending from the umbo; cardinals weak,

but 1 in each valve: Mississippi and St. Lawrence valleys; Hudson River;
on muddy bottoms.

L. recta (Lamarck). Black sand shell (Fig. 912, A). Shell elon-
gate, compressed, heavy, rounded in front and triangular behind, 11 cm.
long, 5 cm. high, and 3 cm. wide, black in color; 2 cardinals in each
valve: Mississippi and St. Lawrence valleys, in large lakes and rivers;
used in button-making.

L. anodontoides (Lea). Yellow back. Shell elongate, swollen, tri-
angular behind, 8 cm. long, 35 mm. high, 27 mm. wide, bright yellowish-
brown in color; 2 cardinals in each valve: valley of the Mississippi and
of the Gulf of Mexico; used in button-making.

Fig. 912

Fig. 913

Fig. 912 — A, Lampsilis recta; B, L. luteola; C, L. iris (Baker). Fig. 913 —
Strophitus edentulus (Baker).

L. luteola (Lamarck) (Fig. 912, B). Shell elliptical, inflated,
rounded in front and oval behind, 11 cm. long, 6 cm. high, and 48 mm.
wide; color light or dark green; 2 cardinals in each valve: Mississippi
and St. Lawrence valleys, in lakes and rivers; common.

L. iris (Lea) (Fig. 912, C). Shell small, elliptical, compressed, 57
mm. long, 3 cm. high, 2 cm. wide; color yellowish, with numerous wide,
interrupted, green, radial rays ; 2 cardinals in each valve : New York to
Illinois, south to Texas; common.

L. ligamentina (Lamarck). Mucket. Shell elliptical, thick, and
heavy, 10 cm. long, 6 cm. high, and 35 mm. wide, yellowish or greenish
in color, with dark radiating rays ; 2 cardinals in each valve : Mississippi
and St. Lawrence valleys; used in button-making.

PELECTPODA

581

2. STROPHITTTS* Rafmesque. Shell inflated, rounded, with a hard,
shining periostracum ; teeth rudimentary, consisting of an irregular ridge
in the left and 1 or 2 faint ridges in the right valves; male and female
shells alike; glochidia not parasitic: 8 species, all American.

S. edentulus (Say) (Fig. 913). Shell ovate, hinder margin forms
an obtuse angle with dorsal margin ; umbo but little in front of the mid-
dle; interior, bluish-white; surface yellowish, with dark rays; lengtn 8
cm. ; height 4 cm. ; width 3 cm. : eastern and central states.

3. ANODONTA Lamarck. Shell thin, oval or elongate, inflated; peri-
ostracum generally smooth and without rays; hinge without teeth, regu-
larly curved; cloacal siphon without papillae; male and female shells
alike: 55 species, 30 American, the animals living usually in muddy
streams and ponds, often buried in the mud.

Key to the species of Anodonta here described:

ox Shell large.

&! Dorsal margin straight A. CATABACTA

6a Umbo with undulating wrinkles A. GBANDIS

&3 Shell with very thick margins A. IMPLICATA

o, Shell small and bright green A. IMBECILIS

A. cataracta Say (A. fluviatilis Gould) (Fig. 914, A). Shell oval,
large, crested behind, deep green in color, with obscure radial rays,
white within, with a lilac tint; hinge margin straight; 11 cm. long, 7 cm.
high, 37 mm. wide; shell
rounded in front and form-
ing an obtuse angle behind :
Atlantic slope, south to
North Carolina; common.

A. grandis Say (Fig.
914, C). Shell elliptical, in-
flated, green or black in
color, with usually faint
radiating rays, 12 cm. long,
7 cm. high, and 5 cm. wide,
or larger; umbo marked with about 5 elevated undulating wrinkles:
central states; common.

A. implicata Say (Fig. 914, B). Shell oval, thick and heavy, with a
rough, light yellowish-green outer, and a pink inner surface, 10 cm. long,
56 mm. high, and 35 mm. wide ; hinder end with a truncated point which
is joined with the umbo by a very pronounced edge :- Atlantic slope as
far south as Virginia ; valley of the St. Lawrence.

* "Metamorphosis without Parasitism," etc., by G. Lefevre and W. C. Curtis,
Science, N. S., Vol. 33, p. 863.

Fig. 914

A, Anodonta cataracta (Gould) ; B, A. implicata;
C, A. grandis; D, A. imbecilis (Baker).

582 MOLLUSCA

A. imbecilis Say (Fig. 914, D). Shell very thin and fragile, ellip-
tical, smooth and shining, 59 mm. long, 29 mm. high, and 21 mm. wide;
dorsal margin straight ; bright grass green in color, with numerous darker
radial rays: valley of the Mississippi.

4. ALASMIDONTA Say. Shell elliptical or rhomboidal, inflated, with
a well-developed posterior ridge; umbo rather prominent, with a few
coarse, parallel ridges; interior surface bluish; hinge with imperfect
teeth, 1 large cardinal being under the umbo in the left valve and a
smaller one in front of it and 1 cardinal in the right; laterals blurred:
15 species, all in North America, in muddy rivers, often buried several
inches in the mud.

Key to the species of Alasmidonta here described:

at Shell large.

&! Height about half the length A. COSTATA

6a Height nearly equal to length A. COMPLANATA

a, Shell small A. TJNDULATA

A. costata Rafinesque (A. rugosa Barnes). Shell elliptical, 16 cm.
long, 8 cm. high, and 46 mm. wide; surface with heavy lines of growth,
which form prominent wrinkles on the upper posterior portion; yellow-
ish-green in color, with delicate radial rays ; cardinals thick : Mississippi
and St. Lawrence valleys.

A. complanata Barnes. Hatchet back (Fig. 915). Shell very thick,
high, and irregular in shape, the posterior portion being quadrate or
triangular; umbo with 4 coarse elevated ridges arranged in a double loop,
the apex of which points forwards; color black or
brown, sometimes reddish; cardinal in right valve
very long; 15 cm. long; 11 cm. high; 5 cm. wide:
entire central part of continent, as far south as
Arkansas; common; sometimes contains pearls;

Fig. 915-Atoami- USed in makinS buttons.

donta^ompianata A. undulata (Say) (Fig. 916, B). Shell short,

ovate, inflated, dark green in color, with alternately
yellowish and dark radiating rays ; umbo large and prominent, with 3 or
4 concentric oblique undulations; 1 cardinal in each valve supported by
a strong internal rib ; 50 mm. long ; 35 mm. high ; 25 mm. wide : Atlantic
slope, south to South Carolina.

5. MARGARITANA Schumacher. Shell large, elongated; hinge teeth
more or less imperfect and small ; laterals sometimes wanting : 6 species ;
circumpolar.

M. margaritifera (L.) (Fig. 916, A). Shell more or less reniform,
thick, black in color; umbo not prominent; length 12 cm.; height 5 cm.;
width 3 cm.; cardinals, 2 large ones in left valve, the posterior grooved

583

in front, 1 in right valve also grooved; laterals wanting: circumpolar, as
far south as north latitude 40 degrees, but wanting in the central part
of the continent; often very common in running streams.

6, UNIO Retzius. Shell usually thick, oval or elongated, rounded in
front and pointed behind; hinge teeth well developed, there being 2
cardinals and 2 laterals in the left, and 1 of each in the right valve;
cloacal siphon fringed: circumpolar; 145 species; about 100 American
species, mostly in the southern states.

U. gibbosus Barnes (Fig. 916, C). Shell rather elongate, thick and
heavy; dull brown in color; umbo marked by 5 or 6 large, wavy ridges;

Fig. 916

Fig. 917

Fig. 916 — A, Margaritana margartifera ; B, Anadonta undulata (Gould) ;
C, Unio gibbosus (Baker). Fig. 917 — Unio complanatus (Gould).

length 8 cm.; height 35 mm.; width 20 mm.: valleys of Mississippi and
St. Lawrence; also Gulf slope; common.

U. complanatus (Dillwyn) (Fig. 917). Shell ovate, compressed,
rather thin, very dark brown or green ; interior usually pink ; hinge with
a single large pyramidal and striated cardinal in the right valve, with a
vestige of a tooth in front of it and 2 pyramidal cardinals in the left
valve; laterals long and slightly curved; length 10 cm.; width 3 cm.:
Atlantic slope, south to Georgia; one of the commonest fresh-water
mussels.

7. ANODONTOIDES Simpson. Shell elliptical, thin, with a smooth,
bright outer surface; umbo with a few coarse, concentric ridges; hinge
teeth reduced to mere rudiments or wanting; inner

surface bluish-white: 2 species.

A. ferussacianus (Lea) (Fig. 918). Length 74
mm. ; height 39 mm. ; width 29 mm. ; color grass green,
sometimes brown: valleys of the Mississippi and St.
Lawrence; common.

8. QUADRULA Rafinesque. Shell triangular, quadrate or rhomboidal,
thick and heavy, inflated; umbo high; hinge teeth well developed; anal
siphon with minute papillae or with none; male and female shell-like;
both the inner and the outer gills carry the eggs: 100 species, in North
America and Asia ; 73 American species, mostly in the Mississippi valley.

Fig. 918
Anodontpides
ferussacianus

(Baker).

584 MOLLUSCA

Key to the species of Quadrula here described:

0j Shell elliptical.

6j Shell smooth Q. BUBIGINOSA

6, Shell coarsely wrinkled Q. UNDULATA

a, Shell round Q. PUSTULOSA

Q. rubiginosa (Lea). Shell elliptical, thick, compressed, dark yellow
in color; umbo marked with 5 or 6 heavy ridges; cardinals double in both
valves ; 7 cm. long ; 6 cm. high, and 3 cm. wide : valleys of the Mississippi
and St. Lawrence.

Q. undulata (Barnes). Blue foot (Fig. 919). Shell squarish, com-
pressed, very thick and heavy; umbo marked by 5 coarse diverging

ridges; cardinals double in both valves;
length 15 cm. ; height 10 cm. ; width 6 cm. ;
color brown or black: valleys of Missis-
sippi and St. Lawrence; also Gulf slope;
common ; used for button-making.

Q. pustulosa (Lea). Shell round, in-
flated, thick, and heavy, 59 mm. long and
nigh and 36 mm- wide> yellowish-brown in
color, with a broad band of dark green
extending from the umbo to the ventral
border; cardinals double in both valves: Mississippi valley; Michigan;
Gulf slope.

FAMILY 6. DEEISSENSIIDAE.

Shell like Mytilus without its pearly lining; umbo at the interior
end; mantles fused below, with both siphons complete and prominent;
foot small, with byssus : 2 genera ; marine.

CONGERIA Partsch. With the characters of the family: several
species.

D. leucophaeta (Conrad). Shell 13 mm. long, 7 mm. high, 6 mm.
wide ; outer surface rough and brownish : Maryland and southwards, on
oysters in brackish water.

FAMILY 7. LUCINIDAE.

Shell round, equivalve, compressed ; anterior muscle impression nar-
rower and much longer than the posterior; foot very long, without
byssus; mantle open below; siphons usually incomplete; ligament more
or less internal : 200 species.

Key to the genera of Lucinidae here described:

ot Hinge teeth present 1. LUCINA

oa No teeth 2. CRYPTODON

PELECTPODA

585

1. LtTClNA Bruguiere. Hinge teeth consisting of 1 or 2 cardinals
and usually 2 laterals in each valve; lunule distinct; foot sometimes
twice as long as the animal, and hollow : 100 species.

L. filosa Stimpson (Fig. 920). Shell thick, regular; hinge margin
straight; surface whitish, with prominent lines of growth; 1 cardinal in
the left and 2 in the right valve ; no laterals ; length
and height 37 mm. ; width 15 mm. : Arctic Ocean to
Patagonia, in rather deep water.

2. CRYPTODON Turton. Teeth absent; foot long
and very slender: 16 species.

C. gouldi (Philippi). Shell minute, white, 7.5
mm. long, 8 mm. high, 2.5 mm. wide : Long Island to
Gulf of St. Lawrence, in 6 to 300 fathoms. jwf (Qoold).

Fi

FAMILY 8. KELLYELLIDAE.

Shell minute, thin, equivalve, round or oval; hinge with 1 or 2 car-
dinals, a prominent anterior lateral, which is beneath the cardinal, and a
posterior lateral, which may be wanting; ligament external; no pallial
sinus ; mantle open below ; anal siphon complete : 1 species on the Atlantic
coast.

TURTONIA Forbes and Hanley. Shell attached by a byssus; shell
oval: in northern seas.

T. minuta (Fabricius) (Fig. 921). Length 2 mm.; height 1.2 mm.;
width 1 mm. ; color yellowish inside and out, blending into purple on the
umbo : circumpolar, south to Cape Cod and Alaska ; common under stones
at low-water mark and among the roots of seaweed; Europe.

FAMILY 9. EBYCINIDAE.

Shell minute, thin, equivalve; hinge with 1 or 2 cardinals of which
the anterior one is oblique; laterals not constant; ligament internal; no
pallial sinus; mantle united below, with 3 open-
ings, a posterior anal opening, a median one for
the foot, and an anterior branchial opening; foot
long, with byssus; viviparous: marine; 5 genera.
KELLIA Turton. Shell without pallial sinus
and with 1 lateral tooth in each valve: about 35
species.

K. planulata Stimpson (Fig. 922). Shell minute but not very thin,
oval, white, with a brownish periostracum, 4 mm. long, 3 mm. high, and
1.5 mm. wide: Arctic Sea to Long Island Sound, under stones and in
shallow water; not common.

Fig. 921 Fig. 922

Fig. 921 — Turtonia mi-
nuta (Gould). Fig. 922—
Kellia planulata (Gould).

586 MOLLUSCA

FAMILY 10. CYKENIDAE.

Shell small, oval or more or less triangular, thin, greenish or yellow-
ish in color; 1 to 3 cardinals and both anterior and posterior laterals in
each valve ; small pallial sinus or none ; foot elongate, flattened ; ligament
external; eggs hatched in the inside pair of gills; mantle open below
with more or less complete siphons : several hundred species, all in fresh
or brackish water, living usually in small streams, ponds, and lakes,
either in or on sand or mud or on submerged plants; the young have a
byssus by which they often suspend themselves.

Key to the genera of Cyrenidae here described:

G! Umbo median or towards the anterior end ................... 1. SPH^ERIUM

oa Umbo towards posterior end ................................ 2. PISIDIUM

1. SPHJERIUX Scopoli (Cyclas Bruguiere). Shell thin, ovoid, green-
ish; cardinals small or rudimentary, 1 arched cardinal being in the right
and 2 in the left valve; laterals compressed; umbo usually a little in
advance of the middle; siphons elongate, of unequal size, the branchial
being the largest, and neither being closed except at the base : 75 species ;
cosmopolitan; about 20 in this country.

Key to the species of Sphcerium here described:

«! Umbo in front of the center; sliell solid.
&! Lines of growth coarse .................................. S. STAMINEUM

62 Surface almost smooth .................................. S. STRIATINUM

aa Umbo median.
&! Shell fragile, light-colored ................. . ............. S. OCCIDENTALE

6, Shell solid, dark-colored .................................. S. SULCATUM

S. stamineum (Conrad). Shell large, inflated, oval, 14 mm. long,
11 mm. high, and 9 mm. wide; surface shining, yellowish or brownish in
color, with coarse lines of growth; umbo made prominent by a number
of coarse, rounded ridges: eastern and central states; common.

S. striatinum (Lamarck). Shell elongated, yellowish in color, 10.5
mm. long, 7.5 mm. high, 6 mm. wide, with a smooth shining surface and
delicate lines of growth: entire country; common.

S. occidentale Prime (Fig. 923). Shell round, with the umbo median
small, fragile, inflated, light yellowish in color, 7.5 mm.
long, 7.7 mm. high, 4.5 mm. wide; surface shining, with
very fine lines of growth: entire country; very common.
S. sulcatum* (Lamarck). Shell large, oval, inflated,

°(Baker?!6 rather solid, with coarse lines of growth, 18 mm. long, 13
mm. high, and 10 mm. in width; surface smooth and dark
brown in color ; lateral teeth in a straight line with the cardinals instead of
at right angles to them : entire country ; not so common as the others.

* See "Anatomy of Sphaerium sulcatum Lam.," by G. A. Drew, Proc. Iowa Acad.
Sci., Vol. 3, p. 173, 1895.

PELECTPODA 587

2. PISIDIUM Pfeiffer. Shell minute, round or oval; greenish or
yellowish umbo a little back of the middle, and directed backwards; 2
cardinals in the left and 1 in the right valve; laterals lamelliform, 1 in
the right and 2 in the left valve ; anal siphon alone present ; foot tongue-
shaped, capable of great extension: 60 species; cosmopolitan; about 20
in America.

Key to the species of Pisidium here described:

G! Shell triangular P. COMPBESSUM

aa Shell round or oval.

fex Shell without ventral yellow band P. ABDITUM

62 Shell with darker yellow ventral band P. VABIABILE

aa Pallial sinus very large ; siphons separate.

P. compressum Prime. Shell solid, triangular, inflated, very oblique ;
umbo elevated, with a wing-like appendage on the summit ; dorsal margin
acutely arched; length and height 4.5 mm.; width 3 mm.; color yellow
or brownish: entire country; often common.

P. abditum Haldeman (Fig. 924). Shell oval, solid, 4.25 mm. long,
3 mm. high, and 2.5 mm. wide; surface smooth, shining,
bright yellowish in color; 1 arched cardinal in the right
and 2 in the left valve ; laterals strong and curved : entire
country; the commonest species.

P. variabile Prime. Shell round, solid, inflated, with
umbo very much elevated, 4.5 mm. long and high, and 3.1 ?Bak*erf
mm. wide; surface smooth with heavy lines of growth,
light yellow or greenish in color, with a yellow ventral zone: entire
country north of Virginia; common.

SUBORDER 2. TELLINACEA.

Shell equi valve, elongate or more or less triangular; pallial sinus
very large, extending forwards sometimes almost to the anterior adductor
muscle; mantle edges usually open below; siphons very long, and usually
separate; foot and palps large; 2 adductor muscles: 7 families; marine.

Key to the families of Tellinacea here described:
Oj Pallial sinus very large ; siphons separate.
&x Ligament external.

Ci Inner margin of shell not crenulated 1. TELLINIDAE

c2 Inner margin of shell crenulated 3. DONACIDAE

&2 Ligament partly internal, inserted in a pit in the shell 2. SEMELIDAE

ca Pallial sinus not so large ; siphons fused 4. MACTBIDAE

FAMILY 1. TELLINIDAE.

Shell compressed, equivalve, with 1 or 2 cardinal teeth, and usually
1 lateral in each valve \ pallial sinus very large ; ligament external, promi-
nent ; mantle widely open below and in front ; siphons very long, slender,
and separated : over 600 species, in all seas, chiefly littoral.

588 MOLLUSCA

Key to the genera of Tellinidae here described:

di Shell over 12 mm. long.

&! Shell elliptical ; lateral tooth present 1. TELLINA

62 Shell round or ovate ; no laterals 2. MACOMA

oa Shell under 6 mm. in length 3. GASTBANELLA

1. TELLINA L. Shell slightly inequivalve, oval, rounded in front,
with an oblique ridge behind; umbo nearly central; 2 cardinals and usu-
ally posterior and anterior lateral in each valve: 300 species, chiefly in
the tropics, where the shells are often highly colored.

T. tenera Say (Fig. 925). Shell 14 mm. long, 9 mm. high, and 3 mm.
wide, thin, delicate, white or pinkish in color, polished, sometimes con-
centrically banded ; umbo a little back of the middle ; 1 of
the cardinals rudimentary in each valve: Gulf of St.
Lawrence to west coast of Florida, on sandy beaches;
Fig 925 often common; West Indies.

iUna tenera, T. tenella Verrill. Shell same in size and color as

(Dall).

above; anterior dorsal margin straight or concave; pos-
terior end short and rounded; umbo at the posterior third: Long Island
and Vineyard Sounds in 4 to 10 fathoms.

2. MACOMA Leach. Shell oval, round or triangular, equivalve,
swollen, gaping at the ends; 2 weak cardinals; no laterals; anal siphon
long; branchial short: 100 species, in all seas.

M. tenta Say. Shell oval, very convex, thin, white, with pointed
umbo; posterior part narrowed; length 15 mm.; height 10 mm.; width 5
mm.; 2 cardinals in the right and 1 in the left valve: Cape Cod to
Florida; common in muddy bays; West Indies.

M. baltica (L.) (Fig. 926). Shell nearly round, thin, slightly nar-
rowed behind, 23 mm. long, 18 mm. high, and 9 mm. wide ; 2 cardinals in

Fig. 926 Fig. 927 Fig. 928

Fig. 926 — Macoma laltica (Gould). Fig. 927 — Gastranella tumida (Verrill).
Fig. 928 — Cumingia tellinoides (Gould).

each valve: Arctic Ocean to Georgia, very common in shallow water; in
muddy bays the shell is thick, of bluish or rusty color, and covered with
a dark periostracum, in sandy localities pure white or pinkish or yellow-
ish and thin; Pacific coast; Europe.

3. GASTRANELLA Verrill. Shell minute, elongate, more or less irreg-
ular; 2 cardinals in each valve; no distinct laterals; siphons long and
separate: 1 species.

PELECYPODA 589

G. tumida Verr. (Fig. 927). Shell with rounded ends, compressed
posterially; ventral margin variable, being convex, straight, or concave;
color white with purple umbo ; length 4 mm. ; height 2.5 mm. ; width 1.5
mm.: Long Island Sound to Cape Hatteras.

FAMILY 2. SEMELIDAE.

Shell thin, round or ovate, gaping and unusually twisted at the
hinder end; external ligament short; internal ligament in a pit; hinge
teeth weak: many species.

CTJMINGIA Sowerby. Shell oval, often irregular in form; hinge with
a small anterior cardinal and usually 2 elongated lateral teeth in each
valve: 10 species.

C. tellinoides (Conrad) (Fig. 928). Shell thin and fragile, 15 mm.
long, 11 mm. high, 5 mm. wide, rounded in front, and triangular and
pointed behind; lateral teeth wanting in the left valve; color bluish-
white: Cape Cod to west coast of Florida; West Indies; often common
in shallow water.

FAMILY 3. DONACIDAE.

Shell more or less triangular, wedge-shaped, usually thick; liga-
ment external and short; foot very long; mantle open below; gills very
different in size : about 6 species, on the southern Atlantic coast ; marine
or in brackish water.

DONAX L. Shell rounded in front and behind; mantle fringed; 2
cardinals and 1 lateral in each valve: 100 species.

D. fossor Say. Shell small, elongated in front, obliquely rounded
and very short behind; surface with radiating striations; inner margin
crenulated; length 12 mm.; height 7 mm.; width 4 mm.; color white:
south shore of Long Island to Texas, in shallow water; common.

FAMILY 4. MACTBIDAE.

Shell equivalve, more or less tri-
angular, closed or slightly gaping;
pallial sinus quite short; 2 liga-
ments, an external and an internal,
the latter contained in a deep trian-
gular pit ; hinge with 2 divergent car-
dinal and usually 2 lateral teeth;
mantle open below; siphons long Fig. 929-3f oof ra soK^aima (Gould),
and fused, and with fringed orifices: numerous species.

1. MACTRA L. Shell slightly gaping at the ends; umbo prominent;
foot large : 150 species, in all seas, especially in the tropics.

M. (Spisula Adams) solidissima Dillwyn. Giant clam (Fig. 929).
Shell large and solid; color brown or white; length 15 cm.; height 12

590 MOLLUSCA

cm. ; width 7 cm. : Labrador to Cape Hatteras ; common on sandy bottoms
in shallow water; sometimes used for food; Europe.

M. lateralis Say. Shell small, triangular, very convex; color white,
with a brown periostracum ; length 15 mm.; height 12 mm.; width 10
mm.: Nova Scotia to Texas; West Indies; in shallow water on muddy
bottoms; often very abundant, especially in Long Island Sound.

2. LABIOSA Schmidt. Shell oblong, widely gaping, with the poste-
rior dorsal border reflexed and with a distinct ridge below: about 2
species on the Atlantic coast.

L. lineata Say. Shell oval, the surface unequally and slightly
wrinkled; color white; length 7 cm.; height 5 cm.; width 28 mm.: New
Jersey to Texas; West Indies; in shallow water.

SUBORDER 3. VENERACEA.

Shell round, oval, or elongate ; usually thick and solid ; mantle edges
usually open below; siphons usually short and more or less united; pal-
lial sinus present; 2 adductor muscles: 3 families, all marine.

Key to the families of Veneracea here described:

di Shell regular and thick 1. VENEBIDAE

a, Shell more or less irregular and thin 2. PETBICOLIDAE

FAMILY 1. VENEBIDAE.*

Shell regular, heavy ; ligament external ; hinge usually with 3 diverg-
ing teeth in each valve ; laterals not constant ; pallial sinus usually small ;
mantle open below: several hundred species, in all seas, those in the
tropics often very brightly colored.

Key to the genera of Veneridae here described:

Oi Margin of shell crenulated.

6j Shell large with a rough surface 1. VENUS

6, Shell small and smooth 2. GEMMA

a. Margin not crenulated.

&! Shell ovate 3. CALLOCABDIA

6, Shell round, as high as long 4. DOSINIA

1. VENUS L. Shell thick and round or ovate, inner lower margin
minutely crenulated; cardinal teeth 3 in each valve; laterals absent;
lunule distinct; ligament prominent; siphons short, unequal, and more
or less separated ; mantle margins fringed : numerous species, in all seas.

V. mercenaria L.f Hard-shell clam. Round clam. Quahog (Fig.
930). SJiell ovate or heart-shaped; anterior end short and truncated;

* See "Synopsis of the Family Veneridae and of the North American Recent
Species," by W. H. Dall, Proc. U. S. Nat. Mus., Vol. 26, p. 335, 1902.

t See "Clam and Scallop Industries of New York," by J. L. Kellogg, Bull. 43,
N. Y. State Museum, 1901. "Feeding Habits and Growth of Venus Mercenaria," by
same, Bull. 71, same.

PELECYPODA

591

Fig. 930 — Venus mercenaria
(Gould). 1, lunule; 2, umbo;
3, ligament.

posterior end bluntly pointed; umbo directed forwards; surface dirty

white, with prominent, sharp, concentric ridges ; inner surface dull white,

lower margin violet or purple; length 11

cm. ; height 9 cm. ; width 6 cm. : Gulf of St.

Lawrence to Texas, on sandy and muddy

bottoms in shallow water, very common

south of Cape Cod; used extensively for

food; the shells were used by the Indians

in the manufacture of wampum, the violet

portion forming the most valuable pieces.
V. cancellata L. Shell heart-shaped,

white, usually with brown spots; surface

with concentric ridges and radial furrows ; length 4 cm. ; height 27 mm. :

Cape Hatteras to west coast of Florida ; West Indies.

2. GEMMA Deshayes. Shell round, the umbo being nearly central;

3 cardinal teeth in the left and 2 in the right valve; pallial sinus long,

narrow, and ascending; lunule indistinct; margin crenulated within: 1

species on the Atlantic and Pacific coasts.

G. gemma (Totten). Gem shell (Fig. 931). Shell small, with a

smooth shining surface and concentric ridges; color yellowish, white, or
pink; umbo and hinder end amethyst; length 4 mm.; height
3.5 mm.; width 2 mm.: Labrador to Cape Hatteras, in the
sand in shallow water or between tide marks; often very
common; San Francisco.

3. CALLOCARDIA Adams. Similar to Venus, but the
margin of the shell is not crenulated; hinge with 3 car-
dinal teeth in each valve and 1 or 2 laterals: numerous species; cos-
mopolitan.

C. convexa Say (Fig. 932). Similar in appearance to Venus
mercenaria; length 43 mm.; height 35 mm.; width 24 mm.; no purple on
inner surface; siphons very long: Nova Scotia to

Florida; often common.

4. DOSINIA Scopoli. Shell orbicular, com-
pressed, with concentric ridges; hinge like Cal-
locardia; lunule distinct; margin of shell not
crenulated; pallial sinus large, oblique, ascend-
ing; siphons united throughout: 100 species, in
shallow water.

D. discus Reeve. Shell smooth, with 5 regular concentric grooves;
umbo pointed, with a large oblong groove underneath; muscle impres-
sions very large; color yellowish-white; length 66 mm.; height 61 mm.;
width 22 mm.: Virginia to Texas; common.

Fig. 931

Gemma

gemma.

(Gould).

Fig. 932 — Callocardia
convexa (Gould).

592 MOLLUSCA

FAMILY 2. PETBICOLIDAE.

Shell elongate, or more or less irregular in form, thin, and with ends
rounded; 2 or 3 delicate teeth in each valve; no laterals; pallial sinus
deep ; mantle closed in front with an opening for the small foot ; siphons
long, united at the base: 2 genera, in shallow water and between tides,
where the animals bore into clay, limestone, and coral, making round
holes the diameter of the shell.

PETRICOLA Lamarck. With the characters of the family: 13
species.

P. pholadiformis Lam. (Fig. 933). Shell elliptical, swollen, gaping;
umbo near anterior end ; surface curved, with radiat-
ing grooves and ridges, those at the anterior end
being coarse, those back of the umbo being fine;
length 32 mm.; height 17 mm.; width 15 mm.; in-
terior with radiating furrows: Gulf of St. Lawrence
(Gould). to Texas, common south of Cape Cod, boring in clay.

SUBORDER 4. CARDIACEA.

Shell equivalve, solid, with or without hinge teeth ; ligament external ;
1 or 2 adductor muscles; siphons short; mantle closed below, with an
opening for the foot ; with or without pallial sinus : 8 families, all in salt
or brackish water, to one of which belongs the gigantic Tridacna gigas of
the Pacific, the shell of which may weigh over 200 kilograms and
measure a meter or more in length.

FAMILY CABDIIDAE.*

Shell heart-shaped, usually with radiating ridges or bands, more or
less chalky in texture; ligament short and prominent; pallial sinus small
or absent; a small and a large cardinal in each valve; laterals not con-
stant but usually present; inner border of shell denticulate; 2 adductor
muscles; mantle open below; siphons short; foot very large and bent:
200 species; cosmopolitan.

Key to the genera of Cardiidae here described:

a-! Shell with radial ribs 1. CARDIUM

a. Shell without ribs.

&! Shell small ; teeth large 2. L^EVICABDIUM

ba Shell large ; teeth small or wanting 3. SEBEIPES

1. CARDITTM L. Cockle. Shell with prominent ribs and thick, often
with spines or scales, closed or gaping behind; no pallial sinus; umbo

* See ''Synopsis of the Family Cardiidae and of the North American Species,"
by W. H. Dall, Proc. U. S. Nat. Mus., Vol. 23, p. 381, 1900.

PELECYPODA

593

Fig. 934

Cardium

pinnulatum

(Gould).

near the center of the shell ; siphons very short, and separate ; 1 or 2 car-
dinals, 1 or 2 posterior laterals and 2 anterior laterals in the right valve,
and 2 cardinals, 1 anterior and 1 posterior lateral in the left valve;
mantle margin with papillae : 100 species.

Key to the species of Cardium here described:

«! Shell large.

6j Occurs north of Cape Cod C. ISLANDICUM

62 Occurs in the southern states C. MAGNUM

aa Shell small C. PINNULATUM

C. islandicum L. Shell large, rounded, with about 36 ribs sepa-
rated by deep grooves, and with concentric lines of growth; periostracum
yellowish-brown, forming a stiff fringe on the edges of the
ribs, but often absent in the dead shell; length 5 cm.;
height somewhat less; width 25 mm.: circumpolar, south
to Cape Cod and Puget Sound, in 5 to 50 fathoms;
Europe.

C. pinnulatum Conrad (Fig. 934). Shell round, small,
thin, with about 26 ribs with a row of arched scales on
each, inside with furrows corresponding to the ribs; length 11 mm.;
height 10 mm.; width 7.5 mm.; color white, interior white or pink:
Cape Cod to Labrador, in 1 to 200 fathoms.

C. magnum Born. Shell large, with about 35 ribs; color yellowish-
brown, with transverse rows of brown spots; length 10 cm.; height
11 cm.; width 75 mm.: Virginia to Texas, in shallow water; West
Indies.

2. LJEVICARDITTM Swainson. Shell oval, oblique; umbo nearly cen-
tral, surface smooth or with slight radial striations : 20 species.

L. mortoni (Conrad) (Fig. 935). Shell small, thin,
globular, pale fawn color sometimes with brown spots,
within bright yellow, with a purplish blotch pos-
terially; surface smooth, without ribs; length 25 mm.;
height 22 mm.; width 17 mm.: Nova Scotia to west
coast of Florida, in shallow water; very common south
of Cape Cod on sandy flats.

3. SERRIPES Beck. Shell nearly round, com-
pressed, rather thin; umbo nearly central, prominent;
surface smooth or slightly radiated; cardinals and
laterals obtuse, almost wanting: 1 species, on both
coasts.

S. grcenlandicus (Gmelin). Shell 70 mm. long, 55 mm. high, and
30 mm. wide; white or drab in color; margin slightly crenulated; foot
serrated : circumpolar, south to Cape Cod and Puget Sound,

cardium mortoni
(Gould). 1, liga-
ment ; 2, cloacal
siphon ; 3, bran-
chial siphon ; 4,
foot.

594 MOLLUSCA

SUBORDER 5. MYACEA.

Shell either regular or irregular, not pearly, with or without hinge
teeth; ligament internal or external; siphons long; pallial sinus present;
2 adductor muscles; mantle closed below with an opening for the small
foot: 5 families, all marine; all burrowing in sand, mud, or rock.

Key to the families of Myacea here described:

d Shell long and narrow, margins usually parallel 2. SOLENIDAE

oa Shell not long and narrow.

6j Left valve with shelf-like process for ligament 1. MYIDAE

6, No such process 3. SAXICAVIDAE

FAMILY 1. MYIDAE.

Shell rather thick, inequivalve, gaping at one or both ends ; ligament
internal, attached in left valve to a prominent shelf-like process; hinge
teeth variable; periostracum wrinkled; pallial sinus large; siphons par-
tially or wholly retractile, united: 250 species.

Key to the genera of Myidae here described :

C! Hinge toothless 1. MYA

oa Hinge with a tooth on each valve 2. CORBULA

1. MYA L. Shell oblong, gaping behind and more or less irregular;
siphons very long and partially retractile, covered with periostracum;
hinge toothless; foot small, with byssus in youth: 3 species, 2 on the
Atlantic and Pacific coasts.

M. arenaria L. Soft-shell clam. Long clam (Fig. 936). Shell
ovate, white, covered with a brownish periostracum; length 10 cm.;

Fig. 936 Fig. 937

Fig. 936 — Mya arenaria (Verrill). 1, foot ; 2, mantle ; 3, cloacal siphon ; 4, branchial
siphon. Fig. 937 — Corbula contracta (Gould).

height 6.5 cm. ; umbo nearer anterior end : Arctic Sea to Cape Hatteras,
between tide lines and in shallow water in mud flats and under stones;
San Francisco; Europe; a common article of food.

M. truncata L. Shell truncated behind ; periostracum thick and
extended posteriorly, forming a tube 15 cm. long; length 7 cm.; height
4 cm.; width 3 cm.: circuinpolar, south to Cape Cod and Puget Sound;
not common; Europe, where it is more plentiful than M.

PELECTPODA 595

2. CORBULA Bruguiere. Shell small, inequivalve, thick, gaping in
front; hinge with an upright tooth in each valve which fits into a pit in
the other; siphons short: 75 species.

C. contracta Say (Fig. 937). Shell 10 mm. long, 6 mm. high, and
5 mm. wide, with a broad, rounded anterior and a pointed posterior end;
surface with regular, smooth, concentric ridges: Cape Cod to Florida, in
sand and mud.

FAMILY 2. SOLENIDAE.

Shell thin, equivalve, long, and narrow, and with gaping ends; liga-
ment external; 1 to 3 cardinals in each valve; no laterals; foot large,
cylindrical; siphons short, united about half their length: 100 species.

Key to the genera of Solenidae here described:

0! Margins parallel 1. ENSIS

fla Margins not parallel ; shell elliptical.

&! Pallial sinus short 2. SILIQUA

6a Pallial sinus very long 3. TAQELUS

1. ENSIS Schumacher. Razor clams. Shell very long and narrow,
with parallel margins, with a slight bend making the dorsal side concave
and the ventral convex ; 2 hinge teeth in the right and 3 in the left valve
near the anterior end ; umbo near same end : 14 species ; in shallow water.

E. directus Conrad (Fig. 938). Shell about 6 times as long as high;
ends truncate ; right valve with 1 projecting tooth^nd an elongated ridge-
like tooth back of it ; left valve with 2 projecting teeth and a double ridge ;

Fig. 938 Fig. 939

Fig. 938 — finals directus (Gould). Fig. 939 — Siliqua costata (Gould).

length 15 cm. ; height 25 mm. ; width 16 mm. ; color yellowish or greenish :
Labrador to west coast of Florida, common in the sand, in which it
buries itself by a digging motion of the foot.

E. viridis (Say). Shell about 5 times as long as high; dorsal mar-
gin nearly straight ; anterior end truncate, posterior rounded ; hinge with

1 tooth in each valve; periostracum light green, glossy; length 5 cm.;
height 10 mm. ; width 0 mm. : Rhode Island to west coast of Florida.

2. SILIQUA Miihlfeldt. Shell elliptical, smooth, with a rib extending
from the umbo across the shell on the inner surface; pallial sinus short;

2 cardinals in the right and 3 in the left valve : 20 species.

S. costata (Say) (Fig. 939). Shell thin, shining, with a greenish
periostracum, 45 mm. long, 18 mm. high, 7 mm. wide: Nova Scotia to
Cape Hatteras, in the sand in shallow water; often very common.

596

MOLLUSCA

Abranchial l

3. TAGELUS Gray. Shell elongated with the dorsal and ventral mar-
gins nearly parallel; umbo central; 2 cardinals in each valve; foot too
large to be retracted into the shell; siphons separated at the end; pallial
sinus very large: 2 species on the Atlantic coast.

T. gibbus (Spengler) (Fig. 940). Shell thick, rounded at both ends;
umbo back of the middle, and ligament back of it; length 9 cm.; height

3 cm.; width 2 cm.: Cape Cod to
Texas, common on muddy bottoms
in shallow water, in which it bur-
rows; Europe

T. divisus ( Speng. ) . Shell small
and delicate> elliptical in shape,
ends rounded> the posterior being
somewhat more acute than the ante-
rior; umbo nearly central; length 35 mm.; height 12 mm.; width 9 mm.;
surface smooth, with a band of purple passing from the umbo across the
shell: Cape Cod to west coast of Florida; West Indies.

FAMILY 3. SAXICAVIDAE.

Shell thick, equivalve, gaping at the ends; hinge toothless or with

1 or 2 cardinals; ligament external, prominent; pallial line sinuous;
pallial sinus present; mantle margins fused, leaving a small opening for
the small foot; siphons large and long, united, covered with a thick
periostracum : 25 species ; cosmopolitan.

Key to the genera of Saxicavidae here described:
di Umbo nearer the anterior end .............................. 1. SAXICAVA

aa Umbo nearer the posterior end ............................ 2. CYKTODARIA

1. SAXICAVA Bellevue. Shell symmetrical when young, with 2 minute
teeth in each valve; adult irregular in shape, toothless; surface coarse-;
ligament external: 12 species, which bore in soft rock and coral.

S. arctica (L.) (Fig. 941). Shell very variable in
form, more or less elliptical, the right valve projecting
partly over the left and generally gaping; length 25
mm.; height 15 mm.; width 10 mm.; surface divided by

2 radiating ridges into 3 equal portions; color white, Soxicnro, arctica
periostracum yellowish: nearly cosmopolitan; circurn-

polar, south to the west coast of Florida and Santa Barbara, Cal. ; very
common north of Cape Cod, boring in limestone or retreating in crevices
of the rocks, among the roots of seaweed, etc.

2. CYRTODAEIA Daudin. Shell elliptical, the posterior end the
shorter; hinge thick, without teeth; ligament external; animal much too
large for the shell : 1 species on the Atlantic coast.

PELECYPODA

597

C. siliqua (Sprengler). Shell very thick and heavy; length 85 mm.;
height 35 mm.; width 24 mm.; periostracurn thick and black: Cape Cod
to the Arctic Ocean, in deep water.

SUBORDER 6. PHOLADACEA.

Shell more or less modified by the boring habit; ligament and hinge
absent; mantle closed; siphons very long and united almost their whole
length ; foot short, often more or less rudimentary ; 3 adductor muscles : 2
families, marine, the animals boring long passages in wood, rock, or clay
by means of a rasping motion of the shell.

Key to the families of Pholadacea:

ot Shell large ; siphons long 1. PHOLADIDAE

a. Shell small; siphons many times as long as shell; shipworms. .2. TEREDIDAE

FAMILY 1. PHOLADIDAE.

Shell rather large, thin, fragile, white, gaping at both ends, armed
in front with rasp-like ridges; pallial sinus deep; dorsal margin of shell
reflected in part over the umbo ; one or more accessory dorsal valves ; an
interior curved muscle process extending from the umbonal cavity: 80
species, which bore symmetrical holes in clay, wood, or rocks; about 12
species on the Atlantic coast.

Key to the genera of Pholadidae here described:

at Dorsal margin of shell reflected over the umbo 1. PHOLAS

a, Dorsal margin but slightly reflected 2. ZIRPH^EA

1. PHOLAS L. Shell elongated and very convex; dorsal margin pro-
tected by 2 accessory valves ; foot large : 20 species, in all seas.

Fig. 942 Fig. 943

Fig. 942 — -Pholas costata (Gould). Fig. 943 — Pholas truncata (Gould).

P. costata L. (Fig. 942). Shell large, 15 cm. long, 5 cm. high, and
5 cm. wide, with about 30 radiating, serrated ribs, the interior being
marked by corresponding depressions; umbo near anterior end; acces-
sory valves horny, not calcareous : Cape Cod to South America, forming
deep burrows in the clay; common in the southern states, rare towards
the north; Europe.

598 MOLLUSCA

P. truncata Say (Fig. 943). Shell 73 mm. long, 37 mm. high, and
31 mm. wide; elongate; anterior end triangular and sharply pointed,
posterior end broad and truncated; anterior portion with radiating
ridges; accessory valves calcareous: Massachusetts Bay to west coast of
Florida; common in the southern states.

2. ZIRPHJEA Leach. Shell oval; cardinal margin slightly reflected;
no accessory valves ; umbo protected by a membrane : 3 species.

Z. crispata (L.) (Fig. 944). Shell thick,
white, rounded posteriorly, triangular and
pointed anteriorly, gaping widely at both
ends; surface divided into equal halves by a
broad furrow extending from the umbo to the
Fig. 944 — Zirphoea crispata lower margin, the anterior half marked by
numerous coarse ridges ; length 60 mm. ; height

35 mm. ; width 34 mm. : circumpolar, south to Cape Hatteras and Cali-
fornia, boring in clay and wood in 9 to 70 fathoms, common towards the
north; Europe.

FAMILY 2. TEREDIDAE.

Ship worms. Animal vermiform, with very long siphons which are
united the greater part of their length and have 2 calcareous pieces called
the pallets (Fig. 945,2) at the point where they separate; valves 3-lobed,
very small, gaping at both ends, forming thus a ring with an interior
curved muscle process extending from the umbonal cavity: 2 genera;
7 species on the Atlantic coast; the animals live in long burrows in wood
or clay, which they form probably by the rasping motion of the shells
and then line with a calcareous coating; they often do great damage to
ships and docks; the burrows usually follow the grain of the wood, but
not always, and usually do not run into one another.
Key to the genera of Teredidae:

at Pallets spatulate 1. TEREDO

oa Pallets feather-shaped 2. XYLOTRYA

1. TEREDO L. Body globular, lying at the inner end of the burrow;
valves 3-lobed, the center lobe being the largest; mantle lobes united,
with a minute opening for the foot; siphons united nearly to the end:
about 20 species, 6 on the Atlantic coast.

Key to the species of Teredo here described :
ox Tubes about C mm. in diameter.
&! Stalk and blade of pallet of equal length.

ct Posterior lobes of shell much larger than the anterior T. NAVALIS

c2 Posterior and anterior lobes of equal size T. NORVEGICA

ba Blade of pallet much longer than the stalk.

G! Blade of pallet obovate T. MEGOTARA

ca Blade of pallet oval T. THOMPSON!

oa Tubes about 3 mm. in diameter T. CHLOROTICA

PELECJPODA

599

T. navalis L. (Fig. 945). Length of tube usually 25 cm. or less, but
sometimes much greater; diameter of tube 6 to 10 mm.; length of shell
6 mm.; width 2 nun.; posterior lobes of shell much larger than the anterior;
pallets rounded on one side and flat on the other, with the stalk and
blade of equal length : Arctic seas to Texas ; very common ; Europe.

T. megotara Hanley (Fig. 946). Length of tube up to 45 cm.;
length and height of shell 6 to 12 mm. ; length of pallet 6 mm. ; width 3
mm. ; posterior lobe large and separated from the umbo by a narrow,
deep, rounded notch ; stalk of pallet half as long as blade, which is obo-
vate: Arctic seas to South Carolina; common in floating wood; Europe.

Fig. 945

Fig. 946

Fig. 945 — Teredo navalis (Verrill). 1, ends of the siphons; 2, pallets; 3, mus-
cular collar by which it adheres to the tube ; 4, posterior lobe of shell ; 5, foot ;
6, anterior lobe of shell. Fig. 946 — Teredo megotara (Gould). 1, shell; 2, pallets.

T. norvegica Spengler. Tube up to 30 cm. long and chambered at
entrance ; length of shell 14 mm. ; height 15 mm. ; length of pallet 21 mm. ;
width 6 mm.; anterior and posterior lobes of shell of about the same
length; pallets with stalk and blade of equal length, the latter being
truncate : New York to west coast of Florida ; Europe.

T. thompsoni Tryon. Length of shell 9 mm. ;
height 12 mm.; anterior and posterior lobes of
equal height ; length of pallet 8 mm. ; width 3 mm. ;
blade of pallet oval and much longer than the
stalk: Cape Cod to Florida; sometimes common.

T. chlorotica Gould. Burrows very small,
lying across the grain of the wood and close
together so as to resemble a honeycomb; length
and height of shell 3 mm.; pallet, paddle-shaped,
5 mm. long: Massachusetts Bay to Florida.

2. XYLOTRYA Leach. Pallets long and
feather-shaped, the blade consisting of articulated
pieces radiating obliquely from the stalk: 10 species.

X. fimbriata Jeffreys (Fig. 947). Shell similar to that of Teredo
navalis; length of pallet 12 mm.; width 2 mm.; tubes 30 cm. or more long:
Massachusetts Bay to Florida: often common.

Fig. 947 — Xylotrya flm-
briata (Gould). 1, shell ;
2, pallets.

600

MOLLUSCA

SUBORDER 7. ANATINACEA.

Shell thin, white and pearly; hinge with or without teeth; ligament
external; mantles united, except where the foot protrudes; 2 adductor
muscles; pallial line variable; siphons mostly united: 11 families, all
marine, including many degenerate forms, which may lack certain organs,
as the foot, adductor muscles, labial palps, and gills.

Key to the families of Anatinacea here described:

as No spatulate hinge lamella.

&! Pallial sinus slight or absent 1. PANDOBIDAE

fca Pallial sinus angulated 2. LYONSHDAE

ca Hinge lamella in each valve 3. ANATLNIDAE

FAMILY 1. PANDOBIDAE.

Shell free or fixed, inequivalve, pearly inside, semi-lunar or trian-
gular in shape ; ligament often with a calcareous ossicle ; pallial line with
or without a small sinus ; siphons short, united except at the end ; mantle
margins united : about 5 species on the Atlantic coast.

CLIDIOPHORA Carpenter. Shell thin; valves closed, attenuated be-
hind; right valve flat, with a diverging ridge; left valve somewhat con-
vex, with 2 diverging grooves at the hinge ; a slight pallial sinus : numer-
ous species.
I

Fig. 948

Fig. 949

Fig. 948 — Clidiophora triliniata (Gould). 1, siphons; 2, foot.
Fig. 949 — Lyonsia hyaUna (Gould).

0. trilineata (Say) (C. gouldiana Ball) (Fig. 948). Shell rounded
in front, hinder end curved upwards, making the dorsal margin straight
or concave ; length 32 mm. ; height 17 mm. ; width 5 mm. : Nova Scotia to
Texas, in shallow water; common.

FAMILY 2. LYONSHDAE.

Shell thin, slightly inequivalve, the left valve being the larger;
pallial sinus obscure; hinge teeth absent; hinge with a narrow ledge
within each valve, to which adheres an ossicle; siphons very short:
several genera.

LYONSIA Turton. With the characters of the family: 18 species.

L. hyalina (Conrad) (Fig. 949). Shell ovate, pearly, and transpar-
ent; anterior end rounded; posterior end elongated; dorsal line nearly

PELECYPODA

601

straight; pallial line obscure; surface with radiating fringed wrinkles;
periostracum dirty white; length 17 min.; height 10 mm.; width 7.5 mm.:
Nova Scotia to Texas, in shallow water; common.

FAMILY 3. ANATINIDAE.

Shell thin, moie or less inequi valve, exterior often granular; hinge
toothless or with a spatulate lamella; ligament often with an ossicle;
pallial line obscure: 14 species on the Atlantic coast.

1. THRACIA Blainville. Shell
nearly equivalve, gaping behind,
smooth; siphons rather long, sepa-
rate; umbo prominent; spatulate
process of hinge in each valve, and
very oblique: 26 species.

T. conradi Couthouy (Fig. 950).
Shell thin, almost round, somewhat
elongated and truncated behind,
whitish in color ; ligament prominent ;
pallial sinus deep; periostracum thin
and brown; length 75 mm.; height 65 mm.; width 38 mm.: Labrador to
Cape Hatteras, buried deep in the sand or mud in shallow water.

2. COCHLODESMA Couthouy. Shell oval, inequivalve, slightly gaping
at both ends; hinge with a spatulate process in each valve and a small

ossicle; an internal rib extends from the hinge to
the posterior margin; siphons long and separate:
several species.

0. leanum (Conrad) (Fig. 951). Shell oval, very
thin; right valve the more convex, the left valve
being nearly flat; length 35 mm.; height 25 mm.;
width 11 mm. : Nova Scotia to Cape Hatteras ; com-
mon in shallow water.

Fig. 950 — Thracia conradi (Gould).

Fig. 951

Gochlodesma leanum
(Gould).

ORDER 5. SEPTIBRANCHIATA.

Ctenidia absent, but replaced by a muscular septum (Fig. 890, D)
pierced by slits extending from the anterior adductor muscle to the point
of separation of the siphons and dividing the mantle cavity into 2 cham-
bers, one lying above the other : 2 families.

FAMILY CUSPIDAEIIDAE.

Shell small, slightly inequivalve, not pearly, much attenuated and
gaping behind; a spatulate cartilage process in each valve; hinge teeth
present or absent; pallial line shallow; mantle closed; siphons short and
united : about 20 species on the Atlantic coast, mostly in deep water.

602 MOLLUSCA

CUSPIDARIA Nardo. Shell slender behind and broader in front, the
right valve being the smaller; umbo strengthened internally by a rib:
numerous species.

C. pellucida Stimpson. Shell thin, white, 12 mm. long, 7.5 wide;
umbo a little in front of the center : Cape Cod and northwards, in deep
water.

CLASS 5. CEPHALOPODA.*

Squids, devilfish, etc. Marine mollusks often of large size and of
high organization, which have a large head and large eyes and a circle of
long arms or tentacles around the mouth, and are mostly without an
external shell (Fig. 740, A).

External Structure.— The body is a bilaterally symmetrical, more or
less cylindrical structure, which is elongated dorsally and made up of two
divisions, the head and the trunk. The head is the ventral portion of the
body, in the middle of the lower surface of which is the mouth, sur-
rounded by the arms. In Nautilus the arms are about ninety in number
.and are without suckers; in the other cephalopods they are either eight
or ten in number and are provided with either prehensile suckers or hooks,
or with both these structures.

The trunk is made up of the visceral mass (Fig. 740, A, 1) and the
mantle (A, 2). The visceral mass is a compact cylindrical structure with
delicate body walls. The mantle is thick and muscular and covers the
visceral mass on all sides, its lower edge being called the collar. The mantle
cavity (A, 4) is voluminous, and is posterior in position and contains the
gills and the external openings of the digestive, excretory, and repro-
ductive organs. It communicates with the outside in two ways, through
the open space around the collar and by means of a conical, muscular
tube called the siphon or funnel (A, 5). By the contraction of its muscular
walls the water in the mantle cavity is shot violently out through the
siphon, and the animal is propelled rapidly through the water in the oppo-
site direction; water is taken into the mantle cavity again through the
collar space. The head, and the siphon can be partially retracted within
the mantle by means of powerful retractor muscles. The external sur-
face is covered with an integument in which amoeboid pigment cells are
present, by the alteration in size of which the color of the animal may
be rapidly changed. Many cephalopods are brilliantly colored.

A shell is present in all cephalopods except in most Octopoda. In
Nautilus, Spirula, and Argonauta the shell is calcareous, external, coiled
in a single plane, and in Nautilus and Spirula divided into chambers by

* See "Report of the Cephalopods of the Northeastern Coast of America," by
A. E. Verrill, Rep. U. S. Fish. Com. for 1879, p. 221, 1882.

CEPHALOPODA 603

transverse partitions. The shell of Argonauta, the paper nautilus, is not
homologous to that of other cephalopods. In the Decapoda, the shell
is concealed in a pocket of the anterior wall of the mantle. It differs
much in shape and composition in the various species, being calcareous in
Spirula and Sepia, but coiled in the former and straight in the latter, and
chitinous and elongate in the squids.

The foot is absent in cephalopods in the form in which it occurs in
other mollusks. The siphon, however, represents the fused epipodia and
the arms are lateral processes of the foot, the basal portion of which has
grown forwards and enveloped the head, so that the mouth comes to lie
in their midst.

Internal Structure.— The mouth is surrounded by a ring-shaped lip
and leads into a muscular pharynx. A pair of sharp chitinous or partly
calcareous jaws, which look a good deal like a parrot's beak, lie just back
of the lip, by means of which the animal tears its prey to pieces. In the
pharynx are the tongue and the radula. The radula is small, as com-
pared with the size of the animal, and consists of a central tooth and
three laterals in each transverse row; marginals are absent in the
Deeapoda, and are represented in the Octopoda by a plate of varying
shape. Two pairs of salivary glands pour their secretion into the
pharynx; in the Deeapoda the anterior glands are united or may be
rudimentary.

The oesophagus is a narrow tube which leads to the stomach; in
Nautilus and the Octopoda a lateral crop is present. The stomach is a
muscular organ with a large thin-walled caBCuin, which acts as a gall
bladder and receives the secretion of the large liver. The two ducts which
pass to the stomach caecum from the liver have in their walls a paired
gland called the pancreas. The intestine leaves the stomach and passes
forward to the anus in the mantle cavity. A glandular pocket at the
anal end of the rectum, called the ink sac, secretes a brown or black
fluid, by means of which the animal clouds the water when fleeing from
an enemy ; Nautilus is without the ink sac.

The respiratory organs consist of a pair of ctenidia (two pairs in
Nautilus) which lie in the mantle cavity. These bear a close relation to
the circulatory system. There are three hearts. The systemic or arterial
heart consists of two auricles (four in Nautilus) which receive blood from
the gills and pour it into a median ventricle, which distributes it through
arteries throughout the body. The blood returns through large veins to
the two branchial hearts at the base of the gills, which send it through
these organs.

The excretory organs consist of a pair of kidneys (two pair in
Nautilus), which open into the mantle cavity near the anus; they also

604 MOLLUSCA

open into the pericardial cavity. The kidneys bear a close relation to
the large veins bringing blood to the branchial hearts.

The main ganglia are massed together around the forward end of
the oesophagus and are surrounded by a protective capsule of cartilage.
On the dorsal side of the ossophagus are the cerebral, on the ventral side,
lying close together, the visceral (viscero-pleuro-parietal) and the pedal
ganglia, which are joined with the cerebral by broad connectives. In
front of the pedal are the brachial ganglia, which are genetically a part
of them and send off large nerves to the arms. Two pairs of large
pharyngeal ganglia, an upper and a lower pair, lie at the base of the
pharynx. A pair of large optic ganglia spring from the brain, and a pair
of large stellate ganglia, which are joined to the visceral by connectives,
lie on the inner surface of the mantle.

The special sense organs are well developed. The eye is a camera
obscura consisting of a deep pit with a retina on its inner surface and
a small opening to the outside for the admission of light. In Nautilus
the eye is of this form. In other cephalopods, a large lens is present at
the opening, and in most forms a transparent cornea is also present in
front of the lens. The superficial similarity of this eye to the vertebrate
eye is very striking. A pair of lithocysts, which are organs of equilib-
rium, lie on the under side of the cerebral cartilage. A pair of pits just
behind the eyes are probably olfactory organs. Osphradia are present in
Nautilus, at the base of the gills.

The sexes are separate. The gonad is single and occupies most of
the upper half of the visceral mass. The ducts leading from it are either
single or paired; they do not join the gonad directly, but come from a
capsule surrounding it, which is a portion of the ccelom, and extend to
the mantle cavity. In the female of most decapods large glandular
structures called the nidamental glands open into the mantle cavity near
the opening of the oviduct, which secrete the egg capsules. The vas
deferens is single (except in Nautilus) and secretes the spermatophores.
These capsules, filled with sperm, are introduced into the mantle cavity of
the female by one of the 'arms of the male, which is often specially modi-
fied for this purpose, and is called the hectocotylus arm. In Argonauta
and one or two other oetopod genera, the hectocotylus arm becomes sep-
arated from the body and enters the mantle cavity of the female with its
load of spermatophores, where it may remain for days, and as it was
supposed at one time to be a parasitic worm, it was given a name by
Cuvier and called Hectocotylus octopodis.

History. — The common cuttle fish of the Mediterranean have been
well-known animals for a very long period of time, and were called polyps
by Aristotle and the Latin and medieval authors. The class Cephalopoda

CEPHALOPODA 605

was created by Cuvier in 1795 to include the same animals it does today.
The epoch-making dissection of Nautilus by Richard Owen resulted in
his subdivision of the class in 1832 into the Tetrdbranchiata and
Dibranchiata, and also the subdivision of these orders substantially as is
still done.

Distribution and Habits.— Cephalopods occur only in the sea, either
in the neighborhood of the coast or in the open ocean or the deep sea.
All are carnivorous, eating great numbers of fish, mollusks, and crusta-
ceans, and often being very destructive to the fisheries. Many kinds, as
the small squids, swim about in schools, while others, as most octopods,
live singly. All cephalopods swim, often with great swiftness, by squirt-
ing water out through the siphon, while the squids also swim by means
of the fins. The animal carries its body in a horizontal position while
swimming, with the posterior side and the siphon undermost. The octo-
pods often crawl about on the bottom on their arms. Cephalopods are the
largest invertebrates and among the largest existing animals. Architeuthis
princeps is the species containing the largest known individuals, the larg-
est examples of which are over fifty feet long, including the arms.

Cephalopods are of use to man in various ways. Many are used for
food. The common squids are used as bait in the cod fisheries. The
calcareous cuttle bone of the cuttle fish (Sepia) was formerly employed
as a medicine, and the ink of the same animal is a common artist's mate-
rial. The shell of Nautilus is also much used in the arts, and for a
variety of useful purposes.

The class contains two orders and about 400 species: about 5,000
fossil species are known.

Key to the orders of Cephalopoda:

Oj Shell large, coiled, chambered, external 1. TETBABBANCHIATA

a, Shell not coiled (except Spirula), internal, often absent. .2. DIBEANCHIATA

ORDER 1. TETRABRANCHIATA.

Shell external and coiled and divided by partitions into chambers
(Fig. 952), all of which are empty and filled with air or a gas, except the
outer one, which contains the body of the animal, and may be as large
as all the rest of the shell ; septa regularly curved and concave in Nautilus,
but in the fossil ammonites often very complex in structure, with a mem-
branous tube called the siphuncle extending from the body of the animal
through all of them, which is central in position in Nautilus and marginal
in the ammonites ; shell composed of 2 layers, of which the inner is pearly ;
4 ctenidia, 4 kidneys, and 4 auricles, but no branchial hearts present;
siphon consists of 2 separate lobes (the epipodia) ; tentacles numerous
and without suckers; eye without lens; ink sac absent: about 4 living

606 MOLLUSCA

and numerous fossil species, grouped in 2 suborders. Of these suborders,
the Ammonoidea, or the ammonites, were abundant throughout the Meso-
zoic age and became extinct before its close.

SUBORDER NAUTILOIDEA.

Shell straight (Orthoceras), bent (Cyrtoceras), loosely (Gyroceras),
or closely coiled (Nautilus), in the fossil species, and closely coiled in all
the living species; septa concave; siphuncle variable in position, often
large: 11 families, with 4 living and 2,000 fossil species, the latter dating
back to the Cambrian and reaching their maximum in the Silurian and
Devonian ages.

FAMILY NAUTILIDAE.

Shell with few whorls, more or less overlapping; septa simple;
siphuncle central or nearly so ; tentacles about 90 in number, consisting of
4 groups of 12 or 13 labial tentacles around the mouth, 2 groups of 17
larger tentacles on each side of the head, 2 thicker tentacles, which combine
to form a hood beneath which the mouth and
its appendages can be retracted, and 2 small
tentacles on each side of the eye: 1 genus.

NAUTILUS L. With the characters of the
family: 4 species; 300 fossil species.

N. pompilius L.* The pearly nautilus
Fig. 952^ction of a && 952>- She11 UP to 25 cm* in Diameter,
Naturaf mstory)Cambridge white with chestnut-brown stripes, and pearly
inside; body about 18 cm. long: Pacific and

Indian Oceans, in rather deep water near the shores; often common;
body used for food, and the shell extensively employed for ornamental
and useful purposes.

ORDER 2. DIBEANCHIATA.

Shell internal (except in Spirula) or absent, either homy or cal-
careous, and not coiled (except in Spirula) ; 2 ctenidia, 2 kidneys, and 2
branchial hearts present; siphon tubular; mouth surrounded by either
8 or 10 arms, which have suckers or hooks; ink sac present; eye with a
crystalline lens ; body cylindrical or globose : about 350 species, grouped in
2 suborders; about 30 species off the Atlantic coast.

Key to the suborders of Dibranchiata :

<*! Ten arms present 1. DECAPODA

a, Eight arms present 2. OCTOPODA

* See "The Anatomy of Nautilus pompilius," by L. E. Griffin, Mem. Nat. A cad.,
Vol. 8, p. 103, 1900. "Notes on Living Nautilus," by Bashford Dean, Am. Nat.,
Vol. 35, p. 819, 1901.

CEPHALOPODA

607

SUBORDER 1. DECAPODA.

Body either elongate or more or less globose, with a pair of fins at
or near the aboral end, and with 10 arms, 4 pairs of shorter arms with
suckers along their entire length, and 1 pair of long
tentacular arms, often more or less retractile, with the
suckers confined to a broad terminal portion; suckers
pedunculate and with a chitinous supporting ring; shell
(Fig. 953) always present, and either chitinous or cal-
careous, and consisting, in its typical form (in the fossil
Belemnitidae), of a solid, conical, terminal rostrum and a
chambered conical phragmocone, which corresponds to the
shell of Nautilus, and is contained in the hollow base of
the rostrum, and whose broad, flat, anterior portion is
called the proostracon: about 250 species, grouped in 3
divisions; about 21 species on the Atlantic coast.

Key to the divisions of Decapoda:

ax Shell calcareous.

&± Shell spiral, with a siphuncle 1. PHRAGMOPHOBA

6, Shell not spiral 2. SEPIOPHOBA

a, Shell chitinous 3. CHONDBOPHOBA

•3

Fig. 953

Diagram of

a belemnite

shell (Leunls).

1, proostra-
con ; 2, phrag-

mocone ;
3, rostrum.

DIVISION 1. PHRAGMOPHORA.

Shell consists of a phragmocone, the septa of which are pierced by
a siphuncle near the inner margin of the whorl, with or without rostrum
and proostracon ; arms with hooks or suckers : 2 families, in one of which,
the fossil Belemnitidae of the Mesozoic age, the shell was
formed of the 3 typical parts (Fig. 953).

FAMILY SPIEULIDAE.

Shell partly internal and partly external, consist-
ing of a loose spiral with 2 or 3 coils, which is the
phragmocone alone; siphuncle contained in a continuous
calcareous canal: 1 genus.

SPIRULA Lamarck. With the characters of the fam-
ily: 1 species.

S. peroni Lam. (Fig. 954). Shell white and pearly, 25 mm. in diam-
eter; body red with brown spots, 55 mm. long, with a terminal sucker:
in deep water in tropical seas; the animal has been seen in only a very
few cases but the shells are common in the Caribbean Sea, and are occa-
sionally thrown up on the beach on Nantucket and other places along the
Atlantic coast.

Fig. 954— The
shell of Spirula
peroni (Cam-
bridge Natural
History).

608 HOLLUSCA

DIVISION 2. SEPIOPHORA.

Shell consists of a highly modified, calcareous phragmocone with air
chambers but without siphuncle, and with a rudimentary rostrum: 1
family.

FAMILY SEPIIDAE.

Body oval ; fins narrow, as long as the body, generally united behind ;
suckers generally in 4 rows; eye with cornea; fourth arm on left heeto-
cotylised: 33 species; cosmopolitan.

SEPIA L. Cuttle fish. Shell (cuttle bone) cal-
careous, large, broad, very thick in front, concave in-
ternally behind; it was formerly used in medicine as
an antacid: 30 species; 10 fossil species.

A. officinalis L. (Fig. 955). Common sepia. Length
of body 20 cm.; color brownish with white spots and
stripes, and with violet fins: Europe; used for food in
the Mediterranean.

Fig. 955
Sepia offlcina- DIVISION 3. CHONDROPHOBA.

Us (Leunis).

arm; 2, fin. Squids. Shell (pen) a straight, chitinous plate,

grooved towards the upper side and representing the
proostracon alone, sometimes with a conical rudiment of the phrag-
mocone at the aboral end ; fins usually rhombic or more or less triangular
and usually at the aboral end of the body: 8 families.
Key to the families of Chondrophora here described:

ot Fins not at the end of the body 1. SEPIOLIDAE

aa Fins at the end "of the body.
&! Siphon with a valve.
d Tentacular arms without hooks.

dj Eyes with a cornea 2. LOLIGINIDAE

da Eyes naked, without cornea 3. OMMASTREPHIDAE

ca Tentacular arms armed with hooks 4. ONYCHOTEUTHIDAE

63 Siphon without a valve 5. CBANCHIIDAE

FAMILY 1. SEPIOLIDAE.

Body short and wide; fins large, rounded, with a narrow base and
near the middle of the body; tentacular arms retractile; eyes with a
cornea; pen (shell) about half as long as the body and in its hinder half,
or absent: 17 species.

1. STOLOTEUTHIS Verrill. Body short, globose; head very large;
arms united together by a broad web; tentacular arms with 8 or more
rows of very small stalked suckers; upper arms hectocotylized ; mantle
united with head on back; pen absent: 1 species on the Atlantic coast.

CEPHALOPODA

609

S. leucoptera Verr. Butterfly squid (Fig. 956). Length of body 30
mm.; fins large, nearly as long as body, transparent, whitish; color bril-
liant, upper surface thickly
spotted with orange brown;
under surface brown and
blue : Gulf of Maine, in 100
fathoms; rare.

2. ROSSIA Owen. Likp
the above, but the mantle
is not united with the
head; pen small; both up-
per arms hectocotylized : 10
species, 3 in North At-
lantic.

Fig. 956

Stoloteuthis leucop-
tera (Verrill).

Rossia sublevis (Verrill).

R. hyatti Verrill. Length of body 40 mm.; breadth 17 mm.; length
of tentacular arms 40 mm.; length of longest sessile arms 18 mm.; 2
rows of suckers towards the base of each arm,
distal portion with about 4 rows; color pink-
ish, spotted with purplish-brown above: Cape
Cod and northwards, in 40 to 150 fathoms;
rather common.

R. sublevis Verr. (Fig. 957). Length 46
mm.; breadth 22 mm.; length of tentacular
arms 25 mm.; of longest sessile arms 22 mm.;
2 rows of suckers on entire arm ; color pinkish,
spotted, with purplish-brown above : Cape Cod
and northwards, in 40 to 150 fathoms; com-
moner than the above. ,

FAMILY 2. LOLIGINIDAE.

Body elongate; fins terminal; shell (pen)
as long as the trunk and pointed; tentacular
arms partially retractile, with 4 rows of
suckers; other arms with 2 rows; fourth arm
on left hectocotylized at tip; siphon attached
to head and with a valve; eye with a cornea:
about 50 species; littoral.

LOLIGO Lamarck. Calamaries. Body elon-
gate ; fins rhombic in shape, united behind : 31
species, cosmopolitan, 3 on the Atlantic coast.

L. pealei Lesueur (Fig. 958). Common squid. Body a flattened
cylinder, pointed at the fin end; fins more than half the length of the

Fig. 958
Loligo pealei (Verrill).

610 MOLLUSCA

trunk; shell (pen) lanceolate, narrow; length 20 cm.; width 6 cm.;
color dark grayish with reddish spots; eggs deposited in long cylindrical
jelly masses, attached together at one end: Maine to South Carolina;
very common.

L. pallida Verrill. Very similar to above; body thick, fins more
than half the length of the trunk; color pale with few spots; length of
body 20 cm. ; length of fin 75 mm. : Long Island Sound.

FAMILY 3. OMMASTEEPHIDAE.

Body cylindrical, elongate; fins terminal, joined together and rhom-
bic; arms usually short, with varying number of rows of suckers; eyes
naked, without a cornea; siphons united by bands to the head; pen slen-
der and small, with a hollow cone at the hinder end : cosmopolitan ; about
25 species, mostly in the open ocean.

Key to the genera of Ommastrephidae here described:

at Size small or moderate 1. OMMASTBEPHES

fla Size very large 2. ABCHITEUTHIS

1. OMMASTREPHES D'Orbigny. Sea arrows. Flying squids. Body
elongate; arms with 2 rows of suckers; tentacular arms not retractile
and with 4 rows of suckers ; siphon valved : 13 species, 4 American.

0. illecebrosus (Lesueur) (Fig. 959). Fins about half as long as the
trunk ; length 30 cm. ; width 3 cm. ; length of fin 8 cm. ; length of sessile
arms 10 cm.; of tentacular arms 18 cm.; color deep blue, passing into
red, spotted, sometimes pale: eastern end of Long Island Sound to Bay
of Fundy and northwards, common north of Cape Cod; very swift in
motion.

0. bartrami (Lesueur). More slender, elongated, and darker-colored
than the above, with a relatively shorter caudal fin: Gulf stream, some-
times off the coast.

0. tryoni Gabb. Length 20 cm. : very common on the coast of Cali-
fornia, where they are caught in great numbers by Chinese fishermen
and dried for exportation to China.

2. ARCHITEUTHIS* Steenstrup. Giant squids. Differs from the pre-
ceding genus in that an irregular group of small, smooth-rimmed suckers
are on each tentacular arm, intermingled with rounded tubercles; suck-
ers of sessile arms strongly denticulate; fins shaped like an arrowhead:
9 species, in the deep sea in all parts of the world, most of the specimens
accurately known having been captured in the North Atlantic.

* See "The Colossal Cephalopods of the North Atlantic," by A. E. Verrill, Am.
Nat., Vol. 9, p. 21, 1875.

CEPHALOPODA

611

A. princeps Verrill (Fig. 960). Length of body up to 6 m.; of the
tentacular arms 11 m. and more ; of the sessile arms 3 m. ; of beak 12 cm. ;
diameter of suckers 30 mm., of the eyes 35 cm.: in the deep sea, thrown
up occasionally on the coast of Newfoundland ; the largest cephalopod.

FAMILY 4. ONYCHOTEUTHIDAE.

Body cylindrical, fins terminal or lateral ; tentacular arms very long
and furnished with retractile hooks as well as suckers; shell lanceolate,
with a terminal cone; eye naked, without a cornea: 23 species; pelagic.

Fig. 959

Fig. 960

Fig. 959 — Ommastrephes illecebrosus (Verrill). Fig. 960 — Architeuthis princeps

(Verrill).

ONYCHOTETTTHIS Lichtenstein. Body elongate; sessile arms without
hooks and with 2 rows of non-denticulate suckers ; tentacular arms, thick,
with 2 rows of strong hooks, with a group of rounded suckers at their
base: 10 species, 1 on the Atlantic and 1 on the Pacific coast.

0. banks! Leach. Head with 11 longitudinal ridges; fins rhombic,
wider than long, about half the length of the body; length 15 cm.; color
brownish, with blue around the eyes : iii all seas ; often common.

612

MOLLUSCA

FAMILY 5. CBANCHIIDAE.

Body cylindrical; head small, with large eyes, which are without
cornea; sessile arms short; tentacular arms long and slender; shell

lanceolate: 13 species.

LOLIGOPSIS Lamarck. Body elongate,
attenuate behind, with large fins; siphons
not valved: 8 species.

L. pavo (Lesueur). Peacock squid
(Fig. 961). Body very long, being 1 m.,
including tentacles; fins about one-fourth
the length of the body, rounded in outline ;
color red, spotted: Arctic seas, south to
Cape Cod; very rare on our coasts.

SUBORDER 2. OCTOPODA.

Body more or less globose, generally
without fins; 8 arms, with suckers usually
sessile; no shell except in Argonauta; no
nidamental glands: about 140 species,
grouped in about 5 families.

FAMILY 1. AEGONAUTIDAE.

Female with a thin, symmetrical, spiral
shell, without septa, which is secreted by
terminal expansions of the two upper arms
and is used as an egg-case, which the animal can leave at will; male
very small, with the third arm on the right hectocotylized : 1 genus; in
all the warmer seas.

ARGONAUTA L. Argo-
naut. Paper nautilus. With
the characters of the fam-
ily : 11 species, 1 on the At-
lantic and 1 on the Pacific
coast.

A. argo L. (Fig. 962).
Shell whitish, ribbed, with
2 rows of sharp protuber-
ances on the periphery, 20

pin lonp" Ipnp-tVi of fpmfllp Fi&- 962 — Argonauta argo. A, shell; B, animal

without shell (Verrill).
20 cm.; color whitish or yel-
lowish with red dots ; length of male 25 mm. : Atlantic Ocean, occasionally
on the coast of the central and southern states.

Fig. 961 — Loligopsis pavo
(Verrill).

CEPHALOPODA

613

FAMILY 2. OCTOPODIDAE.

Devil-fishes. Head very large; arms elongated, webbed, similar;
suckers in 2 rows and sessile; mantle united to the head by a broad,
dorsal commissure; third arm on right hectocotylized : about 8 genera.

OCTOPUS Lamarck. Sea polyp. Body round; arms long; no fins:
50 species ; cosmopolitan ; 2 species on the Pacific coast, 4 on the Atlantic.

0. bairdi Verrill (Fig. 963). Body
short, thick, covered with small tubercles,
75 mm. long, 35 mm. wide, bluish-white in
color, specked with brown; arms short, 10
cm. long, webbed a third of their length:
common north of Cape Cod in rather deep
water; Europe.

O. punctatus Gabb. Body ovate, 9 mm. long; length of arms 22
mm.; color red, spotted: common from Alaska to Lower California, in
tide pools; it grows much larger in open water, where the length of the
body may be 30 cm., and that of the arms 5 m.

Fig. 963 — Octopus bairdi
(Verrill).

PHYLUM 7.
ECHINODERMATA.*

Marine animals with a radially symmetrical, five-rayed body, with cal-
careous spicules or plates in the body wall, and a system of tubes extend-
ing throughout the body known as the ambulacral or water-vascular
system.

External Form. — The larval echinoderm is typically a minute, bilat-
erally symmetrical animal (Fig. 964) which swims about actively in the

surface waters of the sea; it goes
through a complicated metamor-
phosis and is finally transformed
into the radially symmetrical adult,
which lives on or near the bottom,
either creeping, or in some cases
swimming, slowly about, burrowing
in the sand or in the rocks, or
permanently attached by a stalk to
one place. The body of the adult
is made up of ten principal di-
visions, which radiate from the
main body axis like the spokes of a
wheel (Fig. 965). These divisions
are the five radii or rays (1) and
the five interradii or interrays (2),
which alternate with them. The main axis of the body passes between
its two most important surfaces. These are the oral or under surface,
in the center of which is usually the mouth (3), and the aboral or
upper surface, which is opposite to it, and in most cases contains the
anus (4). The relative length of its main axis determines the gen-

* See "Invertebrate Animals of Vineyard Sound," by A. E. Verrill, Rep. of U. S.
Fish Com. for 1871. "Echinodermata," by W. N. Lockington, Stand. Nat. Hist.,
Vol. 1, 1888. "Echinodermen," by H. Ludwig and O. Hamann, Bronn's Klasseu u.
Ord., 2 Bd., 3d Abt., 1889-1904. "Distribution of the Echinoderms of Northeastern
America," by A. E. Verrill, Am. Jour. Sci., Vol. 49, p. 127, 1895. "Echinoderms of
the Woods Hole Region," by H. L. Clark, Bull. U. S. Fish. Com., Vol. 22, p. 543, 1902.
"Les Echinodermes," by Delage et H6rouard, Traite" de Zool. Coner, 1903. "Echino-
dermata," by E. W. MacBride, Camb. Nat. Hist., 1906. "Echinoderras of Connec-
ticut," by W. R. Coe, Bull. No. 19, St. Geol. and Nat. Hist. Sur., 1912. "A Biological
Survey of Woods Hole and Vicinity," by F. B. Sumner and others, Bull. Bur. Fisheries,
Vol. 31, 1911.

614

Fig. 964 — Larvae of echinoderms (after
J. Miiller). A, youngest stage, common
to all the classes ; B and C, two stages of
the auricularia (Holothurioidea) ; D and
E, two stages of the bipinnaria (Asteroi-
dea) ; F, a pluteus (Echinoidea). 1,
mouth ; 2, anus.

DESCRIPTION

615

eral shape of the body. In some echinoderms this axis is very short,
as in the starfish, the oral and aboral surfaces are near together, and
the body is flat and disc-shaped; in these animals the oral surface is

Fig. 965 — Diagrams illustrating the radiate structure of echinoderms. A, star-
fish, oral aspect ; B, sea urchin, oral aspect ; C, sea urchin, lateral aspect ; D, holo-
thurian, lateral aspect (Boas). 1, radius; 2, interradius ; 3, mouth; 4, anus.

the under one, on which the animal moves about, and the main body
axis is perpendicular to the ground. In others the main axis is
long and the body is
consequently long and
worm-like, as in holo-
thurians; the oral sur-
face, with the mouth,
is not undermost in
these animals, but is at
what may be called its
anterior end, and the
animal lies with its
main axis parallel with
the ground. In crinoids
the oral surface lies
uppermost (Fig. 968),
and in many of them a
long stalk extends from
the aboral surface at-
taching the animal to
the sea bottom.

In starfishes, brit-
tle-stars, and crinoids
the radii are greatly elongated, forming five or more large arms, which
radiate from a central disc (Fig. 965, A). Many echinoderms also show
a decided tendency towards the development of a secondary bilateral
symmetry and always move with a certain radius in advance (Fig.

ig.

showing the arrangement of certain of the organs!
A, a section through the disc and one arm of a star-
fish ; B, a section through a sea urchin (altered from
Boas). 1, mouth; 2, anus; 3, peristome; 4, ring
canal ; 5, stone canal ; 6, stomach ; 7, radial canal ;
8, ampulla ; 9, madreporite ; 10, ambulacral foot ; 11,
liver ; 12, dentary body ; 13, gill ; 14, calcareous
plates ; 15, papula.

616 ECH1NODEEMATA

Projecting from the surfaces of the radii into the surrounding
water are soft, tubular structures known as the ambulacral appendages
or podia, which are parts of the ambulacral system (Fig. 966, 10).
In many echinoderms a sucker disc terminates each appendage; the
animal attaches this to objects in the water and then by the muscular
contraction of the appendage pulls itself slowly along; such ap-
pendages are called ambulacral or tube feet. Ambulacral append-
ages perform a variety of functions, however, besides that of locomotion ;
they may assist in the taking of prey and are also always, whether pro-
vided with sucker discs or not, important tactile, respiratory, and perhaps
excretory organs. Spines also, sometimes controlled by muscles and
sometimes not, as well as other special structures, project from the body
of starfishes, sea-urchins, and brittle-stars.

Special sense organs are very poorly developed. Some starfishes,
holothurians, and sea-urchins have pigment eyes, and most sea-urchins
and some holothurians have static organs, but these and all other echino-
derms must depend principally on their tactile sense for a knowledge of
their environment.

The color of the body is hi many echinoderms brilliant and varied,
often being orange, red, or purple; some are quite transparent.

Internal Structures. — The body wall of echinoderms contains charac-
teristic calcareous bodies (Fig. 966,14). These are least developed among
the holothurians, where they are minute spicules, which give a certain
rigidity to the body wall, and are best developed in the sea-urchins, in
which they consist of polygonal plates, forming a closed case. The body
cavity is voluminous and contains the vegetative and reproductive organs.
The alimentary tract is well developed and extends from the mouth to
the anus (6). The ambulacral system is an extensive system of tubes,
which are filled with a watery fluid containing blood or lymph corpuscles.
The main part of the system is a ring-shaped canal or tube (4) which
surrounds the oesophagus, and five radial canals (7) which spring from
the ring canal and traverse the five radii. From these radial canals, and
in some cases from the ring canal also, branch canals go off to the ambu-
lacral appendages (10), which, as we have seen, project from the surface
of the body into the water. Sac-like expansions of the branch canals
called ampullae (8) are usually present. From the ring canal an addi-
tional vessel called the stone canal (5), because its walls usually contain
minute calcareous bodies, passes, in starfishes, sea-urchins and brittle-
stars, to the external surface of the body, where it opens to the outside
through a perforated plate called the madreporite (9), and in holothurians
and crinoids ends free in the body cavity. In crinoids and some holo-
thurians more than one stone canal may be present. The purpose of the

DESCRIPTION 617

stone canal is to introduce sea water (or the body fluid) into the ambu-
lacral system. The fluid in it is, however, never pure sea water but
always contains lymph bodies in the form of amoeboid cells. Lymph
glands occur in the ambulacral system of many starfishes in the form
of small sacs called Tiedemann's vesicles, which spring from the wall of
the ring canal. In many echinoderms there also arise from the ring canal
elongated sacs known as Polian vesicles. These seem to serve chiefly as
regulators of the pressure in the ambulacral system, but they may also
give rise to the amoeboid cells. An organ of somewhat problematical
function called the axial organ, which surrounds the stone canal, without,
however, opening into it, is also probably a lymph gland, and has, besides,
a close relation to the reproductive organs; in most echinoderms this
organ is itself surrounded by the axial sinus, a tubular portion of the body
cavity.

The fluid in the ambulacral system is kept in circulation by means of
cilia on the inner surface of the tubes, and muscle fibers in their walls ;
valves are present where the ambulacral feet join the branch canals.

There are two or three systems of nerves in the echinoderm body.
These are (1) the superficial oral system, consisting of a ring nerve
around the mouth or the oesophagus, and five radial nerves which pass
along the five radii; (2) the deeper oral system which accompanies the
superficial system; and (3) the apical system which is confined to the
aboral body wall. The first of these systems is present in all echinoderms
and innervates the ambulacral system and the digestive canal. The second
is wanting in crinoids and certain sea-urchins; the third is especially
prominent in crinoids, but is wanting in holothurians.

The general surface of the body, including the ambulacral append-
ages, plays the greatest part in the performance of the functions of res-
piration and excretion. In starfishes and sea-urchins, where the surface
is ciliated, its importance in this particular is increased; the papulae of
the former and the peristomial gills of the latter still further enlarge its
functional area. Most holothurians have special respiratory organs, and
the bursae of brittle-stars may function as such.

The body cavity is not a single space but a complex system of spaces
and canals, some of which are often cut off from the rest, and which
contain a circulatory fluid similar to that in the ambulacral system. There
is one principal space, which may be called the body cavity proper, con-
taining the greater part of the viscera, and small spaces and canals which
extend to every part of the body and surround the principal organs. The
most important of these canals are the radial blood vessels, which consist
of a ring vessel and five radial vessels, following the ambulacral canals
and the radial nerves. No heart is present, and the blood fluid is kept in

618 ECHINODERMATA

circulation by the cilia which line the inner surface of the spaces and
vessels.

The sexes are separate in the majority of echinoderms, the males and
females being more or less alike in appearance. The genital organs are
simple in structure. Except in the holothurians and some sea-urchins,
they consist of five gonads or pairs of gonads, which open separately to
the outside. In the holothurians, they consist of a branched gonad which
opens to the outside near the mouth; this gonad may be homologous to
the axial organ of other echinoderms. No accessory genital glands or
organs are present among echinoderms, and the sperm and ova are
usually thrown into the surrounding water, where fertilization takes
place.

Echinoderms have great regenerative powers; an arm broken off is
replaced, and a holothurian may regenerate its digestive tract and other
viscera if these are voided when the animal is irritated. Certain star-
fishes and brittle-stars reproduce asexually, by transverse division.

Distribution and Habits.— Echinoderms are inhabitants of the sea
bottoms. They are found in all parts of the globe, the various species
ranging from the shore line to the greatest depths. A few forms can
swim, but the greater number creep slowly about, feeding on small animals
and plants, organic matter in the sand and mud, or seaweeds.

History.— Leuckart, in 1847, first recognized the Echinodermata as
one of the main subdivisions of the animal kingdom. The name origi-
nated with Klein, who, in 1734, applied it to the sea-urchins. Lamarck
added the starfishes and Cuvier the holothurians to the group, which
formed a class under the Zoophyta or Badiata. Leuckart's great service
consisted in showing that Cuvier^s Radiata formed an assemblage of
animals which are without natural relationships and in splitting it into
the Ccelenterata and Echinodermata, the former being very primitive ani-
mals without a distinct body cavity or a digestive tract, both of which are
possessed by the latter.

The Echinodermata contain about 4,000 species, grouped in five
classes.

Key to the classes of Echinodermata:

ttj Arms present.
&! Arms with small branches called pinnules ; oral surface directed upwards.

1. CRINOIDEA

&a Arms without pinnules ; oral surface directed downwards.
<*! Oral surface of arm with a deep longitudinal (ambulacral) groove.

2. ASTEROIDEA

c, Ambulacral grooves absent 3. OPHIUBOIDEA

a3 Arms absent.

&! Body covered with movable spines ; no oral tentacles 4. ECHINOIDEA

63 Body without spines ; oral tentacles present 5. HOLOTHUBIOIDEA

CRINOIDEA 619

CLASS 1. CRINOIDEA.

Sea-lilies. Feather-stars. Echinoderms which, either throughout life
or during their youth alone, are attached by a stalk to the sea bottom.
The body of the typical crinoid is made up of three parts, the disc or
calyx, the arms, and the stalk. The calyx is more or less cup-shaped and
forms the central mass of the body. Its oral surface, with the mouth,
is directed upwards; near the mouth and raised above the surface in an
interradius is the anus. The aboral side is directed downwards and is
attached to the stalk when this is present. In some crinoids the stalk
bears whorls of jointed appendages called cirri. In most living crinoids
the stalk is wanting in the adult animal.

The arms are either five or ten in number, and often branch di-
chotomously. They bear small alternating branches called pinnules which
give them a feathery appearance. Five ambulacral grooves radiate from
the mouth to the arms, and pass along their oral surface, branching with
them, extending to the tips of the pinnules. These grooves are lined
with cilia, which create a current running towards the mouth, to which
they aid in bringing food. Ambulacral appendages are present along
the edges of the grooves, which are tactile, respiratory, and excretory in
function. The general surface of the body is not ciliated. No special
sense organs are present.

Internal Organs.— The calcareous skeleton of crinoids is extensively
developed. The aboral wall of the calyx contains two groups of polyg-
onal plates which fit together closely and are often fused; these are the
basals (Fig. 968,1) and the radials (2). The former are at the end of
the stalk, occupying interradial areas; they are normally five in number,
but may be reduced by fusion, or increased to ten by the addition of five
infrabasals in the radial areas between the basals and the stalk.

The radials are in the radial areas and lie above the basals, one or
more rows of them being present ; interradials are present in some species.
The oral body wall in Holopus and other primitive crinoids contains five
large oral plates; in most crinoids, however, a number of small plates is
here present, or there may be no plates at all. A row of large circular
plates called brachials is present in the arm, which join the radials.

The stalk contains a succession of disc-like plates placed one on top
of another; the cirri are similarly jointed.

The body cavity occupies the calyx, and extends through the arms to
the tips of the pinnules and through the stalk and cirri. In the calyx
it contains a network of connective tissue fibers which are often calcified.

* See "Report on the Crinoidea," by F. H. Carpenter, Reports of the Challenger,
Vol. 26, 1888.

620 ECHINODERMATA

The body cavity contains a blood fluid mixed with sea water, which is
admitted through ciliated pores in the oral wall of the calyx.

The mouth opens into the tubular digestive canal, which runs once
round the main axis of the body cavity and then opens to the outside
through the anus. No digestive glands are present, but certain inter-
radial diverticula of the intestine in Antedon may have a glandular
function.

The ambulacral system consists of a ring canal around the mouth and
five radial canals which branch with the arms and are continued in the
pinnules. The ambulacral appendages along the edges of the ambulacral
groove are without terminal suckers and ampullae. A number of stone
canals, which lack calcareous bodies in their walls, leave the ring canal and
end free in the body cavity. Five groups of ambulacral tentacles also
spring from the ring canal and surround the mouth.

The superficial oral nervous system, consisting of an oral nerve ring
and a radial nerve in each arm, is situated just beneath the outer epi-
thelium; an apical system is also present, consisting of a nerve capsule in
the aboral calcareous plates and large radial nerves which run through
the brachials into the arms. The reproductive organs, the ovaries or
testes, extend throughout the arms and into the pinnules, where they
become ripe, and through minute pores of which the ova or sperm are
'extruded. The five gonads are usually joined with an organ called the
genital stolon, which lies in the axis of the calyx and is homologous to
the 'axial organ of other echinoderms. The sexes are separate.

Distribution and Habits. — The stalked crinoids are deep-sea forms,
and most numerous in East Indian waters, but are also found in nearly
all oceans; they constitute about one-fifth of living crinoid species. The
Antedonidae and Comasteridae are not stalked as adults, and are also
commonest in East Indian waters, varying from the shallow waters along
the shores to great depths, but are also found, and often plentifully, in
almost all seas; they do not occur, however, in the shallow waters of
New England. The stalked forms may be rooted to the bottom, but it is
likely that the stem is occasionally broken accidentally or perhaps by the
animal itself and that it then moves about by means of the arms.
Isocrinus is perhaps never permanently rooted, but anchors itself tempo-
rarily by its cirri, and possibly moves about at will. The Antedonidae
and Comasteridae are found among rocks and coral colonies and move
about slowly, swimming by means of their arms.

History. — Antedon, which has always been the best known crinoid,
was usually classed with starfishes by the earlier zoologists. J. S. Miller,
in 1821, first organized the group under the name Crinoidea, and E.
Forbes, in 1841, raised it to the dignity of an independent class.

CRINOIDEA 621

The Crinoidea contain nearly 500 living species, grouped in a dozen
or more families; about 2,000 fossil species are known.
Key to the families of Crinoidea here described:

at SessUe crinoids (as adults).

&! Calyx attached directly by its base 1. HOLOPODIDAE

6a Calyx attached by a long stalk.

cx Stalk without or with very few cirri 2. BOUBGUETICBINIDAE

ca Stalk with cirri 3. PENTACRINIDAE

o2 Crinoids which are not sessile (as adults).
&! Pinnules cylindrical or somewhat flattened, with very long segments.

4. ANTEDONIDAE
&a Pinnules, at least the lower, more or less prismatic, with short segments.

5. COMASTEBIDAE

FAMILY 1. HOLOPODIDAE.

All the aboral plates of the calyx fused together; calyx joined
directly with the sea bottom, no stalk being present ; 10 short thick arms
present, which curl inwards: 1 genus.

HOLOPUS D'Orbigny. With the characteristics of the family: 1
species.

H. rangi D 'Orb. Height 4 cm. : in the Caribbean Sea ; rare.

FAMILY 2. BOUEGUETICRINIDAE.

Calyx slender, with 5 basals and 5 radials often united, and with
5 or 10 arms ; stalk long, with very few or no cirri : 1 living genus.

RHIZOCRINTTS Sars. Calyx elongate; 5 slender arms with long
pinnules; no cirri except on root of stalk: 15 to 20 species.

R. lofotensis Sars. Arms with 30 to 40 segments, 8 cm. long; stalk
7 cm. long: in Atlantic Ocean, from 80 to 1,900 fathoms.

FAMILY 3. PENTACRINIDAE.

Calyx small ; 5 arms, each dichotomously divided 1 to 10 times, with
small pinnules ; stalk long, with long cirri ; no root : 4 to 5 living genera.

ISOCRINTJS Von Meyer. Calyx with 5 basals; arms divided 3 to 5
times; stalk often very long, and more or less distinctly pentamerous
in cross section: 3 species in the West Indian region.

I. asterias (L.) (Fig. 967). Length of stalk up to 48 cm., of the
cirri 7 cm., of the arms 10 cm. : West Indies, in 80 to 300 fathoms.

FAMILY 4. ANTEDONIDAE.

Crinoids which have a stalk and are sessile only as young animals,
the adult having shed the stalk, except the first segment or the first few
segments which fuse together and bear cirri and are called the "centro-
dorsal;" 5 to 20 or more long arms, on which are pinnules: several

622

ECHINODERMATA

genera with more than a hundred species ; in almost all seas from shallow
water to 2,900 fathoms, among rocks or hydroid or coral colonies or in
algae, climbing about actively by means of their arms and cirri or
swimming about slowly.

ANTEDON Freminville. Mouth central and ambulacral grooves
equal in length; pinnules smooth, one or more of the proximal elon-
gated and flagellate ; centrodorsal hemispherical or nearly discoidal, with
10 to 30 cirri: 35 species.

Fig. 967

Fig. 968

Fig. 967 — tlsocrinus asterfos (Leunis). Fig. 968 — Antedon tenella — a young, attached
individual (Verrill). 1, basal; 2, radial; 3, brachial.

A. tenella (Retzius) (A. dentata Say) (Fig. 968). Ten arms; cen-
trodorsal with 25 to 30 cirri, each with 10 to 16 segments ; diameter 6 cm. :
Atlantic coast, in 35 to 600 fathoms, from New Jersey northwards.

FAMILY 5. COMASTERIDAE.

Similar to the Antedonidae, but differing in that the mouth is excen-
tric, the ambulacral grooves are of unequal length, the proximal pinnules
are serrated, and the centrodorsal is discoidal with few or no cirri: a
dozen genera and numerous species; in all warm seas, chiefly in shallow
water.

1. NEOCOMATELLA A. H. Clark (Comatula Lamarck; Actinometra
J. Muller). Outer segments of cirri with slight dorsal processes; arms
more than 10: 1 species.

ASTEROIDEA 623

N. alata (Pourtales). Twenty arms present; centrodorsal with
about 30 cirri in 2 irregular rows, each with 15 to 18 segments: West
Indian waters, from 78 to 310 fathoms.

2. COMACTINIA A. H. Clark. Segments of cirri without dorsal
processes ; 10 arms present : 3 or 4 species ; in West Indian waters.

C. meridionalis (E. C. and A. Agassiz). Length and stoutness of
arms variable ; segments of genital pinnules very short : Beaufort, N. C.,
and southwards, in 12 to 100 fathoms.

CLASS 2. ASTEROIDEA.*

Starfish. Echinoderms in which the radii are more or less elongated
so that the body has the form of a five-armed star (Fig. 965, A). In
some of them the number of arms is normally greater than five, and
many abnormal individuals are found with more or sometimes less than
this number. The oral surface is directed downwards and on it the
animal rests and moves about; the aboral surface is directed upwards.
Surrounding the mouth is a membranous area called the peristome
(Fig. 966, A, 3). The main axis of the body is short and extends from
the mouth in the middle of the oral to the middle of the aboral surface :
the anus has an excentric position in this surface.

Extending from the peristome along the oral surface of each arm
is the median ambulacral groove, from the walls of which either two or
four rows of ambulacral feet project into the surrounding water (10).
On the aboral surface in an interradius is the
madreporite (9), the external opening of the am-
bulacral system.

The external epithelium is ciliated. Spines or 01

tubercles appear on the surface of all starfishes; FI 969 A and B

some of these especially along the edges of the ^^p^nfa (Ludwig)!
ambulacral grooves are movable. Minute pincer-

like organs called pedicellariae (Fig. 969, A and B), which are
modified spines, are usually present; they may be either sessile
or pedunculate (stalked), and their jaws are either straight or
crossed like scissors. Paxillae (C), also modified spines, are present in
some groups, each paxilla being a thick calcareous rod, the summit of
which is covered with minute spines. Short finger-like projections of
the body wall called papulae (Fig. 966, 15) also appear, especially on the

* See "North American Starfish," by A. Agassiz, Mem. Mus. Comp. Zool., Vol. 5,
1877. "Report on the Asteroidea," Zoology of the Challenger, Vol. XXX, by W. P.
Sladen, 1889. "Asteroidea," by A. E. Verrill, Amer. Jour. Sci., Vol. 49, 1895.
"Revision of Certain Genera and Species of Starfish," by A. E. Verrill, Trans. Conn.
Acad., Vol. 10, p. 145, 1899. "Asteroidea of the North Pacific and Adjacent Waters,"
by W. K. Fisher, Bull. U. S. N. M., 1911.

624 ECHINODERMATA

aboral surface, which are of importance in respiration and excretion. A
red eye spot is present at the tip of each arm, but with this exception
special sense organs do not occur.

Internal Structure.— The calcareous plates which support the body
are of various sizes and joined with one another by muscles and con-
nective tissue fibres. The most regularly arranged of them are the
ambulacral plates, two rows of narrow calcareous rods which form the
roof of the ambulacral groove; between these plates are the ambulacral
pores.

The mouth (1) is a small opening in the middle of the peristome.
From it a short esophagus leads to the large stomach (6), which, with
its folded walls, fills the disc. Joining the aboral portion of the stomach
are the five pairs of extensively branched liver sacs which lie in the
arms. A short, slender rectum passes from the stomach to the anus (2)
and may send off a small branched caecum; anus, rectum, and caecum are
apparently all rudimentary structures, and the anus and caecum may
be absent. The ring canal (4) and the radial canals of the ambulacral
system are extra-skeletal in position, the former lying at the margin of
the peristome and the latter in the middle line of the ambulacral grooves.
Paired branches go from the radial canals to the ambulacral append-
ages, which, except in three or four families, possess terminal sucker
discs and are used for locomotion. One or two rows of these are present
on each side of the radial canal; from each foot a small sac called an
ampulla (8) extends through the ambulacral pore into the body cavity,
the function of which is to aid in extending the foot. The walls of the
ampulla, as those of the foot, are muscular and by their contraction the
ambulacral fluid is forced into the foot. The terminal end of each radial
canal projects freely into the water at the tip of the arm. Two kinds of
glandular sacs may extend from the ring canal through pores into the
body cavity, which furnish lymph cells to the ambulacral fluid; those of
most general occurrence are the Tiedemann's vesicles; the others and
larger ones are the Polian vesicles. The ring canal is joined with the
madreporite by the stone canal (5).

Special respiratory and excretory organs are not present, the ciliated
external surface of the body with the papulae and ambulacral appendages
performing the functions of such organs.

The most important circulatory vessels are a ring vessel and five
radial vessels which lie just beneath the main ambulacral canals; they
are in open connection with the body cavity. The superficial oral nerv-
ous system is epithelial and extra-skeletal in position; each radial nerve
ends at the tip of the arm with an eye. The other nerves are intra-
skeletal and are not strongly developed.

ASTEEOIDEA 625

The sexes are, with rare exceptions, separate. The testes and ovaries
look much alike and consist of five pairs of racemose glands at the base
of the arms, which open to the outside through minute pores in the inter-
radii. Adjoining the stone canal is the cylindrical axial organ enclosed
in the axial sinus, a portion of the body cavity. An extension of the
axial organ forms a ring around the aboral side of the body cavity, from
which a strand goes to each reproductive gland. The axial sinus follows
this extension and also finally encloses the glands themselves. The
larval starfish is either a bipinnaria or a brachiolaria. In some star-
fishes the female forms a brood sac by bending the arms together, in
which the eggs are sheltered.

Distribution and Habits. — Starfish are common animals through-
out the world, being found in all seas from tide lines to very great
depths. They move slowly about on the bottom by means of their
ambulacra! feet and also to some extent by the movements of their arms,
often in schools, devouring the mollusks and crustaceans they meet in
their path. They are important enemies of the oyster fisheries. A star-
fish kills its prey by wrapping its arms about it and everting its stomach
over it (Fig. 970), and slowly digesting its soft parts. Those which have
no suckers on the tube feet, however, can
not do this and are not carnivorous but
feed on minute organisms which they swal-
low. Starfish possess great regenerative
powers and can replace lost arms.

History. — Starfishes were well Known
to Aristotle and also to the medieval
writers on animals. The scientific knowl-
edge of them begins with Linck in 1733, Fig. 970— Starfish feeding (Cam-
whose work was a standard until the time of

Cuvier. In 1816 appeared Tiedemann's comprehensive description of the
anatomy of the animals, and this and Miiller and Troschel 's classification
(1842) laid the foundation of our present knowledge of the group. The
bipinnaria larva was discovered by M. Sars in 1829. The modern classifica-
tion is based upon that of Perrier (1875), and of Sladen (1889).

The class contains 3 orders and about 1,000 species.

Key to the orders of Asteroidea:

av Starfishes with prominent contiguous marginal plates along the sides of
the arms and with 2 rows of ambulacral feet in the arm.

1. PHANEROZONIA

aa Starfishes usually with long arms and without prominent marginal
plates; aboral body wall spiny ; ambulacral feet with suckers.

6j Pedicellariae very rare or absent and not pedunculate 2. SPINULOSA

&, Pedicellariae present and pedunculate .°>. FORCIPULATA

626 ECHINODEEMATA

ORDER 1. PHANEROZONIA.

Either 1 or 2 rows of large marginal plates along the sides of the
arms (Fig. 971), these plates being in contact with one another and
giving the arm a definite margin ; 2 rows of ambulacral feet in each arm ;
pedicellariae often wanting, and when present, sessile : 8 families.

Key to the families of Phanerozonia here described :
at Aboral wall membranous, and covered with paxillae or spines; feet conical;

suckers inconspicuous or absent.

&! Arms long ; feet without suckers ; paxillae present .... 1. ASTBOPECTINIDAE
&3 Body usually pentagonal ; epiproctal projection on aboral surface.

2. PORCELLANASTERIDAE

o2 Aboral wall not membranous ; body often pentagonal ; feet with sucking discs.

6j Aboral wall with closely fitting platos, mosaic-like 3. GONIASTERIDAE

&a Plates of aboral wall form a reticulum.

Ci Body covered with a smooth, thick skin 5. ASTEBOPIDAE

ca Body not covered by a thick skin 4. OEEASTEEIDAE

FAMILY 1. ASTBOPECTINIDAE.

Flattened starfishes with long, slender arms, with a membranous
aboral wall covered with paxillae (Fig. 969, C), with very large marginal
plates (Fig. 971, 2), which may carry long spines, with conical ambulacral
feet which lack the sucking disc, and usually without anus: 9 genera,
with more than 100 species.

1. ASTROPECTEN Gray. Two rows of marginal plates, the lower row
with many spines, the upper row with granules or spines; no pedicel-
lariae: 60 species, in all parts of the world,
mostly littoral.

A. articulatus (Say). Each upper mar-
ginal plate near tip of arm with a small blunt
l-.**' tubercle; size 20 to 25 cm.: New Jersey south-
wards, from the shore to 25 fathoms; often
Pig. 971— Small portion common.

an tarmabofalASro|ienc ten A. duplicatus Gray. Upper marginal plates

paxii°ial7W2/uppeerr)mar: with erect, conical spines; size 15 to 20 cm.:
fheaiower marglnaTpiates! North Carolina southwards ; common in 6 to 15

fathoms.

A. calif ornicus Fisher (Fig. 971). Upper marginal plates without
spines or tubercles; size 12 to 18 cm.: coast of California, in 10 to 240
fathoms; common in Monterey Bay.

2. LTJIDIA Forbes. Only one row (the lower) of marginal plates;
pedieellariae usually present: 25 species, 10 in the Atlantic.

L. clathrata (Say). Aboral surface with crowded paxillae; arms
much flattened; disc small; marginal plates narrow, 50 or more to an
arm; size 20 to 30 cm. : New Jersey to Florida ; often very common.

ASTEROIDEA

627

L. foliolata Grube. Similar to above, but with heavier and more
spines on oral surface; size 30 to 50 cm.: Pacific coast from Alaska to
Mexico, below low- water mark to 190 fathoms; often common.

L. senegalensis (Lamarck). Similar to the above, but with 9 arms;
size 30 to 35 cm.: Florida and the West Indies; west coast of Africa.

FAMILY 2.
POECELLANASTEBIDAE.

More or less pentagonal
starfishes with a membranous
aboral wall covered with paxil-
lae, in the middle of which rises
a tube-like epiproctal projec-
tion; anus wanting; 2 rows of
thin porcelain-like marginal
plates without spines; between
certain of these plates occur
vertical rows of thin folds of
the integument called cribri-
form organs: 25 species. Fig. 972 — Ctenodiscus crispatus (Fisher).

Ctenodiscus Miiller and Troschel. Body stellate or pentagonal;
paxillae on the aboral body wall : 1 species.

C. -crispatus (Retzius) (Fig. 972). Size 7 to 10 cm.; form of body
very variable, from pentagonal to stellate: circumpolar, ranging south-
wards to California and Cape Cod, from shallow water to 1,000 fathoms;
often common off New England; Panama.

FAMILY 3. GONIASTERIDAE.

Flattened, usually pentagonal starfishes
with 2 rows of very large marginal plates;
plates in the aboral wall forming a mosaic,
sometimes with paxillae: 40 genera.

1. MEDIASTER Stimpson. Upper marginal
plates separated by paxillae; aboral plates with
paxillae : 6 or more species.

M. aequalis Stimp. Papulae in twos and
threes ; color in life, bright red ; size 10 to 15 cm. :
Alaska to Lower California, in 9 to 167 fathoms.
2. HIPPASTERIA Gray. Principal skeletal plates each with a central
tubercle ; marginal plates with tubercular spines : 5 species.

H. pharygiana (Parelius) (Fig1. 973). Size 15 to 20 cm.; upper
surface bright red in life: north of Cape Cod, in 20 fathoms or more.

Fig. 973

Hippasteria pharygiana
(Verrill).

ECHINODERMATA

FAMILY 4. OREASTERIDAE.

Thick-bodied starfishes with small marginal plates, and a reticulate
arrangement (Fig. 974 B) of aboral plates: 10 genera.

OREASTER Miiller and Troschel (Pentaceros Linck). Body very
regularly star-shaped, with short arms and large central disc; plates
with tubercles: 40 species, which are all littoral and subtropical or
tropical.

0. reticulatus (L.) (Fig. 974). Diameter 30 to 40 cm.; body very
thick: South Carolina and southwards, in shallow water.

Fig. 974 — Oreaster reticulatus (Tennent). A, outline of body ; B, aboral surface of arm.

FAMILY 5. ASTEEOPIDAE.

Starfishes whose body is covered by a thick, smooth skin, concealing
the underlying skeleton : 7 genera.

DERMASTERIAS Perrier. Body stellate and thick; no spines on the
marginal or aboral plates: 1 species.

D. imbricata (Grube). Size 15 to 20 cm. : on rocks in shallow water:
Alaska to Monterey, California; common.

ORDER 2. SPINULOSA.

Arms usually long and without prominent marginal plates; aboral
body wall spiny and usually with a more or less reticular or imbricated
skeleton; ambulacral feet with sucking discs; pedicellariae rare or absent
and not pedunculate: 5 families.

Key to the families of Spinulosa here described:

di Mouth plates small ; ambulacral groove narrow.

&! Aboral skeleton composed of imbricating scales 1. ASTERINIDAE

&2 Aboral skeleton reticular 2. ECHINASTEBIDAE

o, Mouth plates large ; ambulacral groove wide.

&x Usually more than 5 arms 3. SOLASTERIDAE

&a Five arms present 4. PTEBASTEBIDAE

ASTEE01DEA

620

FAMILY 1. ASTERINIDAE.

Starfishes whose arms are joined by interradial expansions of the
disc, with small marginal plates and with aboral plates usually imbri-
cated: 10 genera.

ASTEEINA Nardo. Body flattened, pentagonal or star-shaped: 32
species, in all seas, and all littoral.

A. folium Liitken. Aboral plates, each with 3 or 4 minute spines;
size 5 cm.; color variable, often blue or greenish: Florida and West
Indies; common on under side of rocks.

Fig. 975 Fig. 976

Fig. 975 — Asterina miniata (Fisher). Fig. 976 — Henricia sanguinolenta (Clark).

A. miniata (Brandt) (Fig. 975). Aboral plates granular; size 6 to
10 cm.; color variable, but commonly red or yellow: Alaska to Lower
California; one of the commonest low-tide species.

FAMILY 2. ECHINASTEEIDAE.

Starfishes with long, slender arms; feet in 2 rows; pedicellariae
wanting; skeleton reticulate and formed of small imbricating plates:
10 genera.

1. HENRICIA Gray (Cribrella Liitken). Disc small; arms long and
cylindrical; aboral plates form a very fine network with small meshes
and numerous minute spines: 20 species; in northern seas.

H. sanguinolenta (0. F. Miiller) (Fig. 976). Body bright red,
purple, lavender, or yellow above and yellowish below; diameter 7 to 10
cm.: common from Greenland to Long Island Sound, ranging as far
south as Cape Hatteras, from low- water mark to 200 fathoms; Pacific
coast; Europe; Asia.

2. ECHINASTER Miiller and Troschel. Arms long and cylindrical;
meshes of aboral skeletal network rather large, with coarse, scattered
spines: 20 species; littoral.

630 ECHINODEEMATA

E. spinulosus Verrill. Disc rather small; color dark violet; size 10
cm.: common on the Florida coast, ranging north to Cape Hatteras or
perhaps New Jersey.

FAMILY 3. SOLASTEEIDAE.

Arms long and slender and often more than 5 in number; aboral
plates reticular, and bearing paxillae; 2 rows of feet and no pedicel-
lariae: 6 genera, mainly in shallow water in temperate seas.

SOLASTER Forbes. Rays 7 to 14; aboral plates form a fine network
with small meshes: 12 species.

S. endeca (L.). Purple sun-star (Fig. 977). Arms 7 to 13, usually
9 to 11 in number, with 2 rows of marginal plates; color reddish-purple

Fig. 977 Fig. 978

Fig. 977 — Solaster endeca (Clark). Fig. 978 — Solaster papposus (Fisher).

above ; size 20 to 35 cm. : common from Cape Cod northwards, from low-
water mark to 150 fathoms; Pacific coast; Europe.

S. papposus (L.). Common sun-star (Fig. 978). Arms 8 to 14,
usually 10 or 11, with 1 row of marginal plates ; color red or variegated ;
aboral network with larger meshes than in S. endeca: Cape Cod north-
wards, being common north of Casco Bay ; Pacific coast ; Europe.

FAMILY 4. PTERASTEEIDAE.

Starfishes with a large disc and short, thick arms; aboral surface
covered with a skin which passes over the spines, enclosing a brood
chamber ; 2 or 4 rows of feet and no pedicellariae : 10 genera.

PTERASTER Miiller and Troschel. Aboral skin with a large central
opening into the broad chamber, provided with valves; oral surface also
covered with a similar skin: 28 species.

ASTEEOIDEA 631

P. militaris (0. F. Muller) (Fig. 979). Arms short and thick; disc
thick and arched ; under side flat ; diameter 9 cm. : circumpolar, south to
Cape Cod and Washington, in 10 to 350 fathoms;
Europe.

ORDER 3. FORCIPULATA.

Pedicellariae pedunculate, with either crossed
or straight jaws; spines conspicuous; aboral skele-
ton reticular: 7 families.

Key to the families of Forcipulata here de-
scribed: (Leunis).

cx Arms not sharply set off from the central disc.

&! Aboral skeletal plates almost contiguous 1. STICHASTEBIDAE

63 Aboral skeletal plates from a reticulum 2. ASTEBIIDAE

oa Arms sharply set off from central disc 3. BEISINGIDAE

FAMILY 1. STICHASTERIDAE.

Starfishes with long, slender arms; aboral plates large and in longi-
tudinal rows ; 4 rows of feet : 4 or 5 genera.

STICHASTER Muller and Troschel. Numerous spines on each side
of the ambulacral grooves: 10 species.

A. albulus (Stimpson). Diameter of disc 2 to 3 cm.; 6 cylindrical
rays, usually in 2 groups, 3 long and 3 short ones: Cape Hatteras (deep
water), to the Arctic Ocean, low-water mark to 200 fathoms; often
common.

FAMILY 2. ASTEEIIDAE.

Starfishes with usually a small disc and 5 to 12 or more arms;
aboral plates with a reticulate arrangement and bearing spines; pedicel-
lariae with straight and crossed jaws; 4 rows of feet: about 10 genera.

ASTERIAS L.* Usually 5 arms present; 1 or more rows of movable
spines on each side of the ambulacral groove; pedicellariae with crossed
jaws around the base of the spines and with straight jaws among the
papulae: numerous species; in shallow water in most seas, being com-
monest in temperate zones, and especially abundant and reaching very
large size on the North Pacific coast of America.

A. forbesi (Desor) (A. arenicola Stimpson; Asteracanthion bery-
linus A. Agassiz). Common star (Fig. 980). Rays stout and tending to be
blunt and cylindrical; spines rather few and coarse; madreporite bright
orange; color very variable, being oftenest greenish-black; diameter 16

* See "Natural History of the Starfish," by A. D. Mead, Bull. U. S. Fish. Com.
for 1899, p. 203, 1900.

632

ECHINODEEMATA

cm. and more : common from Cape Cod southwards, less common or rare
northwards to Maine, from the shore to 30 fathoms.

A. vulgaris Verrill (Asteracanthion pallidus A. Ag). Purple star
(Fig. 981). Rays flattened and tending to be pointed; spines numerous,
tending to form a noticeable median longitudinal row on the aboral sur-

Fig. 980
Fig. 980— Asterias fortesi (Clark).

Fig. 981
Fig. 981 — Asterias rulgaris (Clark),

face of each arm; madreporite pale yellow; color very variable, but gen-
erally some shade of purple ; diameter 15 to 40 cm. : common from eastern
end of Long Island northwards, from the shore to 300 fathoms, ranging in
deep water as far south as Cape Hat-
teras.

A. littoralis (Stimp.). Body thick, with
very broad rays ; color olive green ; diameter
4 to 5 cm.; 2 rows of ambulacral spines:
Caseo Bay to Cumberland Gulf, in shallow
water, often very common on fucus.

A. tenera Stimp. (Fig. 982). Arms cyl-
indrical, slender, and tapering; skeleton
firm, with numerous spines; madreporite
small and nearly white; color varying from
purplish-pink to nearly white; diameter 5
to 8 cm. : from Nova Scotia to New Jersey,
in 10 to 85 fathoms, often common.

A. ochracea Brandt. Aboral plates very extensively developed, with
only small holes between them; a prominent median ridge present on
each arm; body very large and heavy, 60 to 70 cm. across, with arms
6 to 8 cm. in vertical diameter at base; color violet: one of the com-
monest starfishes on the Pacific coast, ranging from Alaska to San
Diego.

Fig. 982 — Asterias tenera
(Clark).

OPHIUROIDEA 633

FAMILY 7. BBISINGIDAE.

Disc small and circular ; arms 8 to 18 in number, long and round and
set off from the disc like those of brittle-stars ; feet in 2 rows ; numerous
pedicellariae : 6 genera, all of the species of which live in the deep sea.

ODINIA Perrier. Disc with papulae on the upper surface ; arms very
fragile: 6 to 8 species.

0. americana (Verrill). Rays 20 in number, about 35 cm. long;
color bright orarige-red : New England coast, in 175 to 400 fathoms ; rare.

CLASS 3. OPHIUROIDEA.*

Brittle-stars. The brittle-stars resemble the starfish in form, but
the five rays are greatly elongated and form slender, cylindrical arms,
which are sharply set off from the central disc and possess no ambulacral
groove. Two rows of ambulacral appendages project from their oral
surface into the water, but these lack terminal suckers and hence are not
locomotory organs: the animal progresses by the snake-like movements
of its arms. As in the starfish, the oral sur-
face, with the mouth in its middle, is di-
rected downwards, and the main body axis
is very short. The mouth is a complex star-
shaped opening bounded by characteristic
skeletal pieces (Fig. 983) ; an anus is not
present. The madreporite (3) is in the
oral wall in an interradius. At the base of
each arm is a pair of slits (1) which open
into a pair of pouches called the genital

bursae ; in Ophioderma each slit is in two pig. 983 — Oral surface of the

, ml ., t . disc and the base of the arms

parts. These organs are possibly respiratory (Coe). i, genital bursa ; 2,

f> ,• 3 i ,1 i n mouth; 3, madreporite; 4,

in junction and are also the receptacles of arm spine- 5 buccal plate- 6

the genital products. 3aw ; 7' °ral papillae'

The external surface is not ciliated; pedicellariae are not present;
spines usually project from the sides of the arms, and spines, scales, or
granules are present on the disc. No special sense organs are present.
In most species the number of arms is five, but there are six normally
in some, and in others, seven or eight. In most of the Astrophytidae
they are more or less branched.

Internal Structure.— The calcareous skeleton is usually well devel-
oped. The upper wall of the disc is flexible and contains a large num-

* See "Report on the Ophiuroidea," by T. Lyman, Challenger Reports, Vol. 5, 1876.
"Ophiuroidea," by H. Ludwig and O. Hamann, Bronn's Tierreich, Vol. 2, 1901. "The
Ophiurans of the San Diego Region," by J. P. McClendon, U. of Cal. Pub., Vol. 6, 1909.

634 ECHINODERMATA

her of small plates or scales, from which spines may project; a pair of
these called the radial shields, which are at the base of each arm, are
usually conspicuous. The plates surrounding the mouth form a complex
system (Fig. 983), the largest ones being the live buccal plates in the
interradii, one of which being also the madreporite. The five interradial
projections, which determine the form of the star-shaped mouth, are
called the jaws, and are composed each of a number of plates, from
which the teeth, tooth papillae, and oral papillae project into the mouth.
The arm contains typically four rows of superficial plates, an oral, an
aboral, and two lateral rows, and these surround an axial row, which
occupies almost the entire interior space of the arm; these plates are
joined together by muscle and connective tissue strands. The paired
ambulacral appendages pass between the ventral and the abutting lateral
plates in each arm. The axial plates originate as paired structures,
which unite more or less completely in the middle line. In a few forms
the arms are without definite superficial calcareous plates. The lateral
plates of the arms usually bear spines.

The mouth leads through a short oesophagus to the sac-like stomach
which fills the disc. No liver sacs, rectum, or anus are present. The
ambulacral canals are intra-skeletal and consist of ring and radial
canals, the branch canals going to the ambulacral appendages, and the
stone canal going to the madreporite. Each radial canal ends in a ter-
minal tentacle; no ampullae are present. The ambulacral appendages
are not locomotory, but tactile, respiratory, and excretory organs,
and are called tentacles. The bursae take in and expel water, and prob-
ably aid in respiration and excretion. The entire nervous system is
intra-skeletal.

The sexes are separate, with rare exceptions. The reproductive
organs consist of a large number of gonads in the interradial areas of
the disc, which open into the ten bursae. These pouches, which are
invaginations of the body wall, receive the genital products and extrude
them into the sea water; in Amphiura squamata and some other forms
they retain them while development goes on, so that in these cases the
young are born in the form of the adult. The gonads are all joined with
the axial organ in a manner similar to that in starfish. The axial organ,
which adjoins the stone canal, and is itself enclosed by the axial sinus,
sends a strand to the aboral side of the body cavity, which there forms a
ring. From this ring branches go to each group of gonads. The axial
sinus accompanies the ring and its branches and finally surrounds each
of the gonads. The larval brittle-star is called a pluteus. Brittle-stars
have great regenerative powers; a lost arm is replaced, and in many
cases the same is true of the upper surface of the disc, which may be

OPHIVROIDEA 635

periodically shed ; in a number of forms asexual reproduction by division
of the disc occurs.

Distribution and Habits.— The Ophiuroidea form the most numerous
class of echinoderms. They live on the sea bottom or among- seaweed
and coral colonies, feeding on small animals or organic matter of all
sorts, and moving about by means of the long arms.

History.— The brittle-stars were included by the earlier zoologists
among the starfishes, Linnaeus having placed them in the genus Asterias.
In 1816 Lamarck erected two new genera, Ophiura and Euryale, to include
all the brittle-stars, but it was not until 1840 that Miiller and Troschel
published the first extended classification of them. In 1841 Forbes first
made the group a separate class of the Echinodermata. The devel-
opment of the pluteus larva was first described by J. MKiller. The modern
arrangement of the class is largely due to T. Lyman and F. J. Bell.

The class contains more than 1,100 species, which may be grouped
in two orders.

Key to the orders of Ophiuroidea:

«! Arms tmbranched and mostly with distinct and regular plates, and

usually without the power of rolling in towards the mouth. .1. OPHIUBAE

ca Arms with superficial plates poorly defined or wanting, often branched,

and with the power of rolling in towards the mouth 2. EUEYALAE

ORDER 1. OPHIURAE.

Brittle-stars with usually 5 unbranched arms which possess distinct
articulating axial plates and cannot (except some of the Ophiomyxi-
dae) be rolled towards the mouth: 7 families.

Key to the families of Opliiurae here described:

ot Arms with distinct and regular superficial plates.
&! Lateral spines on the arms small and close to the surface.

, cx Disc granulated more or less closely 1. OPHIODEBMATIDAE

ca Disc covered with scales or plates 2. OPHIOLEPIDIAE

62 Lateral spines stand out from the surface of the arm.
Cj Oral papillae present.
</! No cluster of tooth papillae at apex of each jaw.

<>! Arm spines solid, often small and few 3. AMPHIURIDAE

ea Arm spines hollow, often long and numerous 4. OPHIACANTHIDAE

d2 A cluster of tooth papillae at apex of each jaw 5. OPHIOCOMIDAE

c2 No oral papillae present 6. OPHIOTRICHIDAE

oa Arms and disc without regular and distinct superficial plates, soft and

flexible «... .7. OPHIOMYXIDAE

FAMILY 1. OPHIODEBMATIDAE.

Oral papillae present, fringing the mouth; disc more or less closely
covered with granules; plates of arm regular and distinct, the lateral
plates bearing spines which lie close to the surface: 10 to 12 genera.

636 ECHINODEEMATA

OPHIODERMA Miiller and Troschel. Disc granular, with 4 bursal
slits in each interradius; brachial spines short and smooth: 18 species;
littoral, tropical, and mainly West Indian.

0. brevispina (Say) (0. olivacea Ayres) (Fig. 984). Disc pentag-
onal, 10 to 15 mm. in diameter ; length of arm 40 to 60 mm. ; color green

or brownish: Cape Cod southwards, from
the shore to 120 fathoms; common towards
the south.

FAMILY 2. OPHIOLEPIDIDAE.

Oral papillae present; disc covered by
scales or plates; arm plates regular, the lat-
eral plates bearing small, closely lying
spines: 25 genera.

OPHIUEA Lamarck. Disc with scales

Fig. 934-7- Ophioderma or plates; indentation of disc at the base of
brevispina (Clark).

usually fringed with minute spines
called the arm comb ; 2 bursal slits in each interradius : over 100 species ;
cosmopolitan.

0. sarsi Liitken. Disc with several large scales surrounded by small
ones; arm comb made up of slender spinelets; 2 scales to each tentacle
on middle of ray ; diameter of disc 15 to 25 mm. ; length of arm 50 to 100
mm.; color olive or brown: Casco Bay and northwards, in 10 fathoms
and more; often very abundant; Europe; North Pacific.

0. robusta (Ayres). Diameter of disc 10 mm.; length of arm about
30 mm.; disc covered with small scales; 1 scale to each tentacle; color
reddish: Cape Cod and northwards, from the

shore to 150 fathoms; Europe.

FAMILY 3. AMPHIURIDAE.

Oral papillae present, fringing the mouth;
plates regular and distinct, the lateral arm
plates bearing small, solid spines, which stand
out from the surface of the arm: about 25 Flg. 935— OpMopholis
genera. aculeata (Clark).

1, OPHIOPHOLIS Miiller and Troschel. Arm spines rather stout and
conspicuous; each upper arm plate surrounded by a series of small
plates; aboral surface of disc covered with scales bearing granules or
small spines: 5 species.

0. aculeata (L.). Daisy brittle-star (Fig. 983 and 985). Upper
arm plates transversely oval; disc spines usually wanting in Atlantic
coast specimens ; color extremely variable ; diameter of disc 2 cm. ; length

OPHIUROIDEA 637

of arm 7.5 to 12 cm.: Long Island Sound northwards, from low-water
line to great depths; common towards the north; Europe.

2. AMPHIPOLIS Ljungman. Disc small, without spines but covered
with scales; arms slender; outer oral papillae very wide, equal to both
the inner ones: 20 species; cosmopolitan.

A. squamata (Delle Chiaje). Six oral papillae in each corner of
mouth, the outer two very wide; 2 scales to each tentacle; color gray or
yellowish; radial shields whitish; diameter of disc 2 to 4 mm.; length
of arm 20 to 39 mm.; viviparous: Long Island Sound northwards, from
low -water mark to 60 fathoms ; Europe.

FAMILY 4. OPEIACANTEIDAE.

Aboral surface of disc with granules or spinelets, which more or less
conceal the scales; oral papillae present; plates of arm regular and
distinct, the lateral plates bearing hollow spines which stand out from
the surface: 20 genera.

OPHIACANTHA Miiller and Troschel. Disc with small spines or
granules; oral papillae long, 7 to 16 being in each corner of the mouth:
about 100 species; cosmopolitan.

O. bidentata (Retzius). Diameter of disc 8 to 15 mm.; length of
arm 40 to 50 mm. : Casco Bay and northwards, in 10 fathoms and more ;
Europe; Bering Sea.

FAMILY 5. OPEIOTKICEIDAE.

Plates on upper side of the arms small ; no oral papillae present, but
a prominent group of tooth papillae at apex of each jaw ; brachial spines
stand out from the surface of the arm : 15 genera.

OPHIOTHRIX Miiller and Troschel. Surface of the disc covered with
small spines and granules; radial plates large and triangular; 1 scale to
each tentacle: 100 species.

0. angulata (Say). With a longitudinal stripe on upper side of
arm; disc 8 to 12 mm. across; length of arms 5 cm.; color very variable,
purplish or greenish : Chesapeake Bay and southwards.

FAMILY 6. OPHIOMYXIDAE.

Arms and disc without distinct and regular plates and covered with
a soft skin, so that the arms can be rolled in towards the mouth; oral
papillae present: 8 genera.

OPHIOMYXA Miiller and Troschel. Disc and arms covered with a
skin; arm spines short and but little imbedded in the skin: 12 to 15
species.

0. flaccida (Say). Diameter of disc 15 to 25 mm.; color olive or
yellowish, sometimes very dark: Florida and West Indies.

638 ECHINODEEMATA

ORDER 2. EURYALAE.*

Brittle-stars in which the arms are often branched and can be rolled
in towards the mouth; axial plates of the arms double, the other plates
rudimentary or wanting, and the surface of the body covered by a soft

skin: 3 families.

FAMILY ASTEOPHYTIDAE.

Girdles of minute hooks on the arms, at least near the tips; teeth
and the mouth and teeth papillae spiniform and indistinguishable from
one another: about 20 genera.

GORGONOCEFHALUS Leach. Disc circular or pentagonal, with radial
shields on the aboral surface; each arm branches at its base, and from
11 to 15 times in addition: 8 species.

G. agassizi (Stimpson). Basket-fish (Fig. 986). Disc 4 to 8 cm.
in diameter; length of arm 14 to 28 cm.: from Nantucket northwards,
from extreme low-water mark to 800 fathoms; common towards the
north.

CLASS 4. ECHINOIDEA.f

Sea-urchins. Echinoderms (Fig. 965), in which the five radii are
not elongated so as to form arms but are approximately of the same
length as the interradii, and the main body axis is short, so that the body
is subglobular in form or disc-shaped. The calcareous plates are exten-
sively developed and, except in the Echinothuriidae, fit closely together,
forming a case, the "test" (Fig. 987), which encloses a spacious body
cavity. The oral surface, with the mouth usually in its center, is more
flattened than the aboral, and is directed downwards; on it the animal
moves 'about. Surrounding the mouth is a circular, flexible area called
the peristome (Fig. 966, B, 3), and projecting from the mouth in most
sea-urchins are five calcareous teeth (Fig. 988). At the edge of the
peristome are, in most species, five pairs of branched outgrowths called
the gills (Fig. 966, B, 13). In the middle of the aboral surface is either
the anus surrounded by a system of plates called the periproct (Fig. 987)
or the madreporite (Fig. 990), the anus in the latter case being in an
interradius at or near the edge of the test.

The ambulacral pores, through which the ambulacral appendages
extend from body cavity to the outside, are, with rare exceptions, present
only in the radii, four rows of pores appearing in each radius. In cer-

* See "Ueber Japanische und andere Euryalae," by L. Doderleln, Abb. 5, K.
Bayer, Akad. Wiss., Math. Pbys., Kl. 2, Supp.

t See "A Revision of the Echini," by A. Agassiz, 111. Cat. Mus. Comp. Zool., No. 7,
1872-1874. "Hawaiian and Other Pacific Echini," by A, Agassiz and H. L. Clark,
Mem. Mus. Comp. Zool., Vol. 34, 1907. "Comp. Morphology of the Echini," by R. T.
Jackson, Mem. Bost. Soc. Nat. Hist. 1911. "The Genera of Recent Clypeastroids,"
by H. I/. Clark, Ann. Am. Mag. Nat. hist., Ser. 8, Vol. 7, 1911.

ECHINOIDEA

639

tain families the aboral ambulacral pores form a characteristic five-armed
figure which somewhat resembles the petals of flower and is called the
petaloid area (Fig. 990,4). Inasmuch as the anus has shifted its posi-
tion in these families to an interradius at the edge or on the oral side of
the body, the latter can easily be divided by a longitudinal plane into a
right and left half; in most spatangoids the mouth has also shifted its
position towards the forward end, thus increasing the bilateral
symmetry.

Sea-urchins are covered with spines which are movable and articu-
late with small tubercles by ball-and-socket joints. In some forms the

Fig. 986 Fig. 987

Fig. 986 — Gorgonocephalus agawlzi (Clark). Fig. 987 — Test of Arbacia — aboral

aspect (Coe). 1, radius; 2, interradius; 3, madreporite ; 4, genital plate; 5, anus;
6, spine tubercle.

spines are very long, and in some their tips are poisonous. A ciliated
epithelium covers all parts of the body, except the large spines of certain
forms. Stalked pedicellariae with usually three jaws occur between the
spines and on the peristome, the movements of which are controlled by
striated muscles. Sphaeridia, minute, spherical bodies which are modified
spines, occur in most cases on the oral surface; they are probably static
organs.

Ambulacral appendages exist in three different forms: (1) loco-
motory feet with sucking discs, which are of very general occurrence;
(2) ten large oral feet which surround the mouth on the peristome and
may be organs of taste or smell; and (3) tactile or branchial appendages,
without sucking discs, which characterize the petaloid area.

Internal Structure.— The calcareous plates in the body wall, which
form the test, fall into three groups, the peristomal, the coronal, and the
apical. The corona forms the greater part of the test. It is composed
of twenty rows of polygonal plates (Fig. 987), which, in most sea-

640 ECH1NODERMATA

urchins, fit immovably together and extend from the peristome on the
oral side to the apical plates on the aboral side of the body. Two of
these rows are situated in each radius (1) and two in each interradius
(2), the radial plates, as we have just seen, being pierced by the
ambulacral pores. The plates of the corona bear the tubercles (6) on
which the spines articulate.

The peristome is sometimes without plates and entirely membranous ;
in some forms small irregular plates are imbedded in it; in some it con-
tains rows of plates which are continuous with those of the corona.
The apical plates occupy the center of the aboral surface. In the regu-
lar sea-urchins (Fig. 987) they consist of the anal plates which surround
the anus (5) and form the periproct, the five genital plates (4) at the
aboral ends of the five interradii, in each of which is a genital pore, and
five radial plates at the aboral ends of the five radii. Each of the latter
is pierced by a pore through which the terminal end of the radial canal
projects; inasmuch as it is pigmented, it was formerly supposed to be
an eye, and the plate is generally called the ocular plate. In the regular
sea-urchins one of the genital plates is the madreporite (3). In the
other sea-urchins the anal plates are not in the apical system and the
arrangement of the other plates is changed, the madreporite being
usually in the center of the group (Fig. 990,3).

The ambulacral system consists of a ring canal (Fig. 966, B, 4)
around the oesophagus and five radial canals (7) which pass along the
radii on the inner surface of the shell to the radial plates, through which
they project. The branches going to the feet possess each an ampulla.
The stone canal (5) passes from the ring canal to the madreporite and
is surrounded by the axial sinus with its axial organ.

The alimentary canal consists of a wide tube (6) which, beginning
at the mouth, winds completely around the inner wall of the body cavity,
then, turning on itself, winds around again in the opposite direction and
ends at the anus. An accessory gut branches off from the intestine near
the mouth and, running along parallel with it, joins it near its middle.
In most sea-urchins 'a complicated dentary apparatus (12), sometimes
called the lantern of Aristotle, surrounds the ossophagus. It is com-
posed of five groups of calcareous plates bound together by muscles, and
from it five calcareous teeth project through the mouth to the outside.

Respiration and excretion are performed by the entire surface of
the body, and especially by the ambulacral appendages, the peristomal
gills, and perhaps the accessory intestine. The superficial oral nervous
system is intra-skeletal, lying along the ambulacral vessels. Special
sense organs are poorly developed. SphaBridia are almost universally
present. In some genera pigment eyes are distributed over the body.

ECHINOIDEA 641

The sexes are separate. The gonads are usually five in number and
lie in the upper part of the body cavity, opening to the outside through
the genital pores. Each is joined by a cord with an apical ring which,
as in the starfish, is connected with the axial organ. The genital products
are thrown into the sea water; the larva is similar in form to that
of the Ophiuroidea, and is also called a pluteus.

Distribution and Habits.— Sea-urchins occur in all seas, being most
numerous in the neighborhood of the coast, although many deep-sea forms
occur. They move slowly about by means of the ambulacral feet and the
spines, and live on small forms of life and organic remains of all kinds;
many species pass large quantities of sand and mud through the intestine.
Some sea-urchins hollow out excavations in rocks, in which they live.
Certain species, in France and Italy and other countries, are used for
food, the genital organs being eaten; over 100,000 dozen sea-urchins are
yearly brought into the fish markets of Marseilles.

History.— Aristotle was acquainted with several species of sea-urchins
and the name Echinus originated with him. He was also acquainted with
certain features of their anatomy, and mentions the similarity in appear-
ance of the dentary apparatus to a lantern. The first attempt in more
recent times to classify them was made by Klein (1734). The knowledge
of sea-urchins did not, however, increase rapidly until the following cen-
tury. In 1816 appeared Tiedmann's important works on their anatomy,
and in the fourth and fifth decades of the century the foundations of the
modern classification were laid by Desor and Louis Agassiz, while the
metamorphosis was studied by J. Muller. In modern times A. Agassiz,
H. L. Clark and R. T. Jackson have done the most to extend the knowl-
edge of the group, especially of the American forms.

Modern Echinoidea contain 4 orders, with about 500 species. More
than 2,000 fossil species 'are known.

Key to the orders of Echinoidea:

«! Without peristomal gills; peristome with plates; mouth central; anus

apical 1. CIDABOIDA

a, With peristomal gills.
&! Dentary apparatus present ; mouth central.

GI Anus apical 2. CENTRECHINOIDA

c, Anus in posterior interradius ; test depressed or discoidal.

3. CLYPEASTBOIDA
&2 Dentary apparatus wanting ; anus not apical 4. SPATANGOIDA

ORDER 1. CIDAROIDA.

Sea-urchins which have no peristomal gills; ambulacral areas nar-
row and inter-ambulacral areas broad, and both continued on the peri-
stome to the mouth; spines large and long: 1 family, with about 60
species, mostly in the warmer seas.

642 ECHINODERMATA

FAMILY CIDABIDAE.

With the characters of the order : 10 to 12 genera.

EUCIDARIS Pomel. Oral and aboral surfaces flattened; test thick;
interambulacral areas 3 times as broad as the ambulacral; primary
spines usually shorter than the diameter of the test, stout, fluted, and
granulated; between these are smaller spines: 3 species.

E. tribuloides (Lamarck). Diameter 4 to 7 cm.; color of primary
spines grayish, broad and flat: South Carolina to Brazil; common; from
shore to 116 fathoms.

ORDER 2. CENTRECHINOIDA.

Sea-urchins with peristomal gills and sphaeridia; mouth central, with
jaws; anus apical: 10 or 11 families.

Key to the families of Centrechinoida here described :

Oj Test more or less flexible 1. ECHINOTHUBIIDAE

o. Test rigid.

6t Large spines hollow 2. CENTBECHINIDAE

6a Spines solid.

Ci Periproct with but few, usually 4, plates 3. ABBACIIDAE

ca Periproct with many plates.

dt Ambulacral plates with 3 pairs of pores 4. ECHINIDAE

dt More than 3 pairs of pores 5. STBONQYLOCENTBOTIDAE

FAMILY 1. ECHINOTHUBIIDAE.

Test flexible, the plates being movable and overlapping one an-
other; peristome with ambulacral plates and feet, but without interam-
bulacral plates: 6 genera.

PHORMOSOMA Wyville Thompson. Difference between oral and
aboral sides marked; primary spines on the oral side encased in a thick
membrane: 4 species.

P. sigsbei (A. Agassiz). Diameter 6 to 8 cm.; spines small, reddish-
orange in color: West Indies, in deep water.

FAMILY 2. CENTBECHINIDAE.

Sea-urchins with peristomal gills; ambulacral areas narrow; inter-
ambulacral areas large; spines long and hollow; the tubercles to which
they are attached with a central perforation; aboral ambulacral feet
without suckers: 9 genera; mostly in the Pacific and Indian Oceans; 20
to 25 species.

CENTRECHINUS Jackson (Diadema Gray). Test circular in outline,
somewhat flattened, about twice as wide as high; colors very dark; blue
eye spots often present on the genital plates and elsewhere: 6 species.

ECHINOIDEA 643

C. antillarum (Philippi) (Diadema setosum Gray). Spines black,
very slender and long, and poisonous; diameter 8 to 10 cm.: Florida
and West Indies ; very common in shallow water among rocks and corals.

FAMILY 3. ARBACIIDAE.

Sea-urchins with a circular outline and with peristomal gills; spines
solid and rather large; ambulacral areas narrow; aboral ambulacral feet
without suckers: 7 genera and 18 species.

ARBACIA Gray. Subglobular or pyramidal sea-urchins; interrays
naked at the aboral end: 5 or 6 species.

A. punctulata (Lamarck) (Fig. 988). Color reddish-brown; diame-
ter 3 to 5 cm. ; height 15 to 25 mm. ; length of spines 20 to 25 mm. : Cape
Cod, southwards to Yucatan, from low-
water mark to 120 fathoms; common.

FAMILY 4. ECHINIDAE.

Sea-urchins with a circular outline,
with peristomal gills and a single pair
of ambulacral plates at the base of each
ray in the peristome; each ambulacral
plate with 3 pairs of pores; periproct
composed of numerous plates: 9 genera

and more than 50 species. Fig. 988 — Arbada punctulata —

. _ . ,m oral aspect (Coe).

1. IiYTECHiNTJS A. Agassiz (Toxop-

neustes Agassiz). Spines short; tubercles all of about the same size and
in several rows; peristome large: 8 species.

L. variegatus (Lamarck). Diameter 5 to 8 cm.; height 3 to 4.5 cm.;
color green, often with more or less purple; spines rather short and
slender: North Carolina to Brazil, from low-water mark to 30 fathoms.

2. TRIPNEUSTES Agassiz (Hipponoe Gray). Large sea-urchins with
a thin shell and numerous small tubercles on which are small spines:
3 species.

T. esculentus (Leske). Test 10 to 15 cm. in diameter, semi-globular;
color white : South Atlantic coast and West Indies ; used for food by the
West Indian negroes.

FAMILY 5. STRONGYLOCENTROTIDAE.

Sea-urchins with a circular outline; 4 to 11 pairs of pores in each
ambulacral plate: 8 genera and about 30 species.

STRONGYLOCENTROTUS Brandt. Spines slender and fluted ; tubercles
not all of the same size, arranged in numerous series and often crowded :
about a dozen species.

644 ECHINODERMATA

S. drobachiensis (0. F. Miiller). Green urchin. Diameter 4 to 8
cm. ; length of spines 8 to 15 mm. ; color green : New Jersey northwards,
very common north of Cape Cod; from shore to 650 fathoms; Europe;
Asia; Pacific coast.

ORDERS. CLYPEASTROIDA.

Sea-urchins in which bilateral symmetry of outer form has been
secondarily acquired; anus in posterior interradius at margin of test or
on oral surface ; test more or less depressed or discoidal ; mouth central,
with a dentary apparatus: 6 families.

FAMILY 1. CLYPEASTEIDAE.

Bilaterally symmetrical sea-urchins with a thick shell covered with
short spines; in the center of the aboral surface is the
madreporite, from which radiate the five petaloid ambu-
lacral areas: 2 genera and 20 species.

CLYPEASTER Lamarck. Shell more or less five-
sided, each petaloid area being wide and well marked;
each pair of ambulacral pores in the petals joined by a
groove; 5 genital pores: about 20 species.

°' s^epressus Gray (Fig. 989). Shell thick and
quite flat; color in life yellowish-green or purplish;
length 12 cm. ; width 8 cm. : from the shore to 40 fathoms ; North Caro-
lina to Brazil.

FAMILY 2. SCUTELLIDAE.

Shell very flat, more or less circular, and covered with minute
spines; in the center of the aboral surface is the madreporite, from
which radiate the five well-marked petaloid areas: 8 genera and about
20 species.

1. ECHINARACHNITJS Leske. Shell a circular disc; each petal wide
and with open ends; 4 genital pores: 5 species.

E. parma (Lamarck). Sand dollar (Fig. 990). Diameter 7 cm.
or less, the shell being slightly broader than long: Long Island Sound
northwards, from low-water mark to 800 fathoms; Pacific coast;
common.

2. MELLITA Agassiz. Test a circular disc pierced by 5 or 6 elon-
gated holes; each petal with closed ends; ambulacral grooves on the
oral side much branched; anus between the mouth and the interradial
hole in the shell: 4 species.

ECHIN01DEA 645

M. quinquiesperforata (Leske). Keyhole urchin (Fig. 991). Five
holes present, 1 interradial and 1 distal to each lateral petal; diameter
of test 8 to 12 cm. : Vineyard Sound southwards, in shallow water ; rare
north of Cape Hatteras.

3. ENCOPE Agassiz. Test heavy, flat underneath, somewhat arched
above, elliptical, truncated behind and with 5 marginal notches or elon-
gated holes; hinder interradial area also with an elongated hole: 6
species, littoral; tropical America.

Fig. 990 Fig. 991

Fig. 990 — Echinarachnius parrna, spines removed (Coe). 1, radius; 2, interradius ;
3, madreporite ; 4, petaloid. Fig. 991 — Mellita quinquiesperforata (Clark.)

E. michelini Ag. Margin of test indented opposite the end of the
petals (at least the lateral ones), these indentations rarely if ever closed
at distal ends so as to form holes; length and width 14 cm. or less:
Florida and Gulf coast.

ORDER 4. SPATANGOIDA.

Body secondarily bilaterally symmetrical; mouth near the forward
end of the body and without a dentary apparatus; anus at or near the
hinder margin of the body; aboral ambulacral areas petaloid, the for-
ward, median area usually differing somewhat from the other four,
which are paired, in appearance: about 36 genera and more than 150
species grouped in 9 families; tropical and subtropical.

FAMILY SPATANGIDAE.

Body more or less heart-shaped; petals well marked: numerous
genera and species.

MOIRA Michelin. Body ovate; apical area behind the middle; am-
bulacral grooves deep and slit-like; mouth far in advance of the middle:
3 species.

M. atropos (Lamarck). Length 5 cm.: North Carolina, southwards;
common in shallow water.

646 ECHINODERMATA

CLASS 5. HOLOTHURIOIDEA.*

Sea cucumbers. Holothurians. Echinoderms in which the m'ain body
axis is very long (Fig. 965, D) so that the form is often quite worm-like.
The oral surface is not directed towards the ground, as in most echino-
derms, but the animal rests on the side of the cylindrical body, with the body
axis parallel with the ground, the oral surface forming the anterior and
the aboral surface with the anus the posterior end. This arrangement may
be sometimes disturbed, however, and in Rhopalodina lageniformis of the
west African coast the mouth and anus are side by side on the upper
surface. The side on which the holothurian rests and which is thus its
ventral side is often flattened and consists of three radii and two inter-
radii, the remaining two radii and three interradii forming the dorsal
surface.

The calcareous plates are mostly minute and the body wall thus
lacks the rigidity of other echinoderms. The external surface is not cili-
ated and is without spines or pedicellariae. The ambulacral appendages
exist in a variety of forms: around the mouth are ten or more long,
branched, oral tentacles; ambulacral feet may occur on all sides of the
body, or only on the ventral side of it, and ambulacral tentacles without
suckers (papillae) may occur on the dorsal side. The oral tentacles are
alone present in several groups. The ambulacral feet and papillae may
occur in rows in the radii or may be scattered irregularly over both radii
and interradii.

Internal Structure. — The alimentary canal is a long tube which runs
from the mouth at the forward end of the body to the anus at the hinder
end, generally turning on itself twice. The hinder portion is enlarged and
from it in several families long tubular sacs extend into the body cavity.
These are of two kinds, which are called the respiratory tree and Cuvier*s
organs, respectively. The former are a pair of extensively branched
organs in and out of which water is pumped through the anus; they are
consequently respiratory in function. The latter are unbranched, glan-
dular tubes connected with the terminal portion of the respiratory tree
and are found only in certain species. They are exceedingly extensile
and sticky and can be thrust out through the anus and be used to entangle
an enemy, having thus a defensive function. The body wall is well pro-
vided with muscles, powerful longitudinal muscles running along the
radii and transverse muscles being in the interradii.

The ambulacral system consists of a ring canal, well within the body
cavity around the oesophagus with one or more Polian vesicles, five radial

* "Holothurians of the Challenger," by H. Th6el, 1886. "Holothurians," In
Bronn's Tierreich, by H. Ludwig, 1889-92. "Holothurioidea," by H. L. Clark, 1901,
Amer. Nat, Vol. 35, pp. 479-496. "The Apodous Holothurians," by H. L. Clark, 1908.

HOLOTHURIOIDEA 647

canals which pass along the inner surface of the radii between or ex-
ternal to the longitudinal muscles, the ambulacral appendages, and the
stone canal. The ambulacral feet are provided with ampullae. Ten-
tacular canals branch off from the radial canals and pass to the tentacles,
which may also have ampullae. The stone canal in most holothurians
does not extend to the body wall but ends free in the body cavity, receiv-
ing through the madreporite the body fluid. In some deep-sea forms and
rarely in synaptids it reaches the body wall; in many holothurians more
than one canal is present. The superficial nervous system consists of a
nerve ring around the mouth and radial nerves which proceed along the
radial ambulaeral canals. Special sense organs are better developed than
any other class of echinoderms and pigment eyes, otocysts, olfactory cups,
and taste papillae are all known. The tentacles also are important tactile
organs. The respiratory and excretory functions are performed by the
respiratory trees 'and the ambulacral appendages.

The reproductive organs consist of a single, branched gonad which
opens to the outside on the dorsal surface either within the ring of oral
tentacles or back of it; this gonad is probably homologous to the axial
organ of other echinoderms. The sexes are usually separate, but certain
hermaphrodites occur. The larval form is called the auricularia. In a
number of species the young are hatched in the body cavity, where they
undergo development, ultimately emerging through a rupture of the
body wall. Several species carry the eggs and young in brood pouches.
Like all echinoderms, holothurians have great regenerative powers;
individuals which have voided the viscera may live and regenerate the
lost parts, and some species have been observed to break themselves
in two by transverse division, each half developing into a complete
animal.

Distribution and Habits.— Holothurians occur in most seas. They
are found at 'all depths, some species moving over the bottom swallowing
sand or mud and catching minute organisms, some living among rocks,
corals, or seaweeds, while others bury themselves in the sand or mud.
They are used for food extensively in the Far East, the trepang of
the Chinese being the dried bodies of HolotJiuria marmorata and other
species.

History.— The name HolotJiuria originated with Aristotle although
much doubt exists as to what animals he applied it. Rondelet, however,
and other medieval authors gave it to undoubted holothurians. The first
anatomical discriptions of holothurians were given by Bohadsch (1761)
and Pallas (1766). LinnaBus in 1758 gave the name to the Portuguese
man-of-war (Physalia), and by a strict interpretation of the law of
priority it should still be given to this genus. O. F. Miiller, however,

648 ECHINODERMATA

in 1776 described a considerable number of species, all of which he in-
cluded in the genus Holothuria, as did other authors of his tune. Cuvier
in 1817 also placed all the known species in this genus, which he first
put in the class Echinodermata, the relationship of holothurians to star-
fish and sea-urchins not having been generally recognized before his time.
Goldfuss (1820), following Oken, divided the group into several genera,
but Jager (1833) again united all in the single genus Holothuria. He,
however, subdivided it into three subgenera and these into tribes, and his
whole arrangement may be considered the foundation of the modern
classification. Of great importance in more recent times have been
Semper's work on the holothurians of the Philippines (1867) and the
anatomical and systematic studies of Selenka and Ludwig.

The class contains two orders and six or eight families, with over
500 species.

Key to the orders of Holothurioidea:

Oi Ambulacral feet present, or if wanting, respiratory tree present.

1. ACTINOPODA
aa Ambulacral feet and respiratory tree both absent 2. PABACTINOPODA

ORDER 1. ACTINOPODA.

This order includes the majority of sea cucumbers and all those in
which the oral tentacles spring from the radial canals alone; ambulacral
feet are present except in the Molpadiidae: 7 families.

Key to the families of Actinopoda here described:

a^ Ambulacral feet present.

&! Oral tentacles branched only at tip 1. HOLOTHUBIIDAE

&a Oral tentacles much branched 2. CUCUMEBIIDAE

at Ambulacral feet absent. . . . : 3. MOLPADIIDAE

FAMILY 1. HOLOTHUEIIDAE.

Holothurians usually elongated and more or less cylindrical in shape,
which have 18 to 30 (usually 20) oral tentacles, the branches of each of
which form a frilled and expanded end; tentacular ampullae present;
genital pore outside the ring of tentacles ; respiratory tree well developed :
6 to 8 genera and about 200 species, which are found principally in the
tropics, especially in the Indian and Pacific Oceans; about 13 species are
used by the Chinese for food, and enter into the commerce of the East
under the name of trepang.

HOLOTHURIA L. Twenty oral tentacles (occasionally more) ; am-
bulacral appendages scattered over the entire body; calcareous bodies
in body wall numerous and very diverse in form: over 100 species, at
least 4 of which occur on the Florida coast.

HOLOTHURIOIDEA 649

H. floridana* Pourtales (H. mexicana Ludwig). Body elongated,
cylindrical, 20 to 40 cm. long; color brown or yellowish, often reddish
below; ambulacral appendages with suckers on the under surface and
with or without them on the upper: Florida and West Indies.

FAMILY 2. CUCUMEBIIDAE.

Holothurians with 10 to 20 branched oral tentacles; ambulacral
feet and respiratory tree present; genital pore often inside the ring
of tentacles: 12 genera and over 200 species.

Key to the genera of Cucumeriidae here described:

Oi Lower surface of body not flattened, the distribution of its ambulacral
appendages not different from that of the upper surface.

&x Feet in rows and mostly confined to the radii 1. CUCUMABIA

6a Feet scattered thickly over the entire surface 2. THYONE

a. Lower surface flattened to form a distinct creeping sole; 10 tentacles;

no feet on the upper surface 3. PSOLUS

1. CUCUMARIA Blainville. Body usually thick, with 10 tentacles
and with feet in rows in the radii, a few feet often being also scattered
over the interradii, at least dorsally: 73 species.

Fig. 992 Fig. 993

Fig. 992 — Cucumaria frondosa (Clark). Fig. 993 — Thyone Mareus (Clark).

C. frondosa (Gunnerus) (Fig. 992). Length 20 to 30 cm.; thick-
ness 10 cm.; color reddish or brown, much darker above than below; a
few ambulacral appendages on the interradii: Nantucket and north-
wards from low-water mark to 200 fathoms; abundant on the Maine
coast; Europe.

C. pulcherrima (Ayers). Length 5 cm.; thickness 2 cm.; body
ovate; color whitish; no feet on the interradii: Vineyard Sound to
South Carolina, in shallow water.

2. THYONE Oken. Body ovate or elongate, with 10 tentacles and
with feet scattered thickly over the entire surface: 39 species.

T. rubra Clark. Red above, whitish below; 20 mm. long; viviparous:
California.

T. briareus (Lesueur) (Fig. 993). Length 12 cm.; thickness 3 cm.;
color dull brown, or black: Vineyard Sound and southwards, in mud
in shallow water; locally common.

• See "The Development of Holothuria floridana," tjy C. L. Edwards, Jour.
Morph., Vol. 20, p. 211, 1909.

650

ECHINODEEMATA

3. PSOLUS Oken. Lower surface of body forms a creeping sole on
which are the feet in rows; 10 oral tentacles; upper surface arched,
without feet, and usually with large calcareous scales: 13 species.

P. phantapus (Strussenfeldt). Body thick, with 3 rows of feet;
anal region caudiform; color brownish, reddish, or yellowish; length
15 cm.: Cape Cod and northwards, from low water to 150 fathoms;
Europe.

P. fabricii (Diiben and Koren). Body wide, with 2 rows of feet,
one row on each edge of the creeping sole; color of upper side bright
red, the under side lighter; length 10 to 13 cm.: Cape Cod and north-
wards, in shallow water; Alaska; Europe; Asia.

FAMILY 3. MOLPADIIDAE.

Body elongated, cylindrical and without ambulacral feet; 15 ten-
tacles usually present, which are either cylindrical or have minute

branches ; tentacular
canals spring from
the radial canals and
usually have ampul-
lae: 8 genera and
about 50 species.

CAUDINA Stimp-
son. Body tapers pos-
teriorly into a more
or less evident tail : 8

B

species.

C.arenata( Gould)
(Fig. 994). Tentacles
short, each with 4
branches at the tip;
color pink or pur-
plish ; length 10 to 17
cm., about a third of which is "tail": Newport, Rhode Island, to the
Gulf of St, Lawrence, from low water to 18 fathoms; locally common.

Fig. 994 — Caudina arenata.

A, a dissection of the animal;

B, anterior end (Gerould). 1,
tentacles ; 2, ring canal ; 3,

onad ; 4, ampulla of tentacle ;

, respiratory tree ; 6, intestine ;
7, mouth ; 8, genital papilla ; 9,
cloaca ; 10, blood vessels.

ORDER 2. PARACTINOPODA.

Holothurians without ambulacral feet, with 10 to 25 feathered,
digitate or simple tentacles, whose tentacular canals spring from the
ring canal, and with 1 to 50 Polian vessels; ampullae, radial canals,
respiratory tree, and Cuvier's organs wanting; mostly hermaphroditic:
1 family.

HOLOTHURIOIDEA

651

FAMILY SYNAPTIDAE.

Characters as given above: 21 genera and nearly 100 species.
Key to the genera of Synaptidae here described:

a: Calcareous bodies are anchors and plates 1. LEPTOSYNAPTA

«2 Calcareous bodies are wheels 2. CHIBIDOTA

1. LEPTOSYNAPTA Verrill. Body long, worm-like, and semi-trans-
parent; 10 to 13 pinnate tentacles present; 1 stone canal and Polian
vessel; calcareous bodies in form of anchors with serrate arms accom-
panied by perforated plates : 9 species.

L. inhaerens (0. F. Miiller) (Fig. 995). Tentacles 12, each of which
has 5 to 7 pairs of side branches; color whitish; length 10 to 30 cm.;
thickness 5 to 10 mm.: Maine to South Carolina; common in the sand
from the shore to 100 fathoms; Pacific coast;
Europe.

L. roseola Verr. Tentacles 12, each of
which has 2 or 3 pairs of side branches; color
rosy red; length 10 cm. or less: Cape Cod to
Long Island Sound, under stones and occasion-
ally in the sand, near low-water mark, not so
common as the preceding; Bermuda.

2. CHIRIDOTA Eschscholtz. Tentacles 12,
each with a short stalk which widens distally
and bears 3 to 10 pairs of side branches ; cal-
careous bodies in form of wheels usually with 6
spokes: 12 to 15 species.

C. laevis (Fabricius). Papillae containing
the wheels in rows of 20 to 30 in each dorsal

interambulacral area and 3 to 12 in each ventral area; color pink to
translucent white ; length 10 to 15 cm. : Cape Cod and.-northwards, from
low-water mark to 45 fathoms, also in deeper water; locally abundant;
Europe; Pacific.

Fig. 995

Leptosynapta inhoerens
(from Bronn).

PHYLUM VIII.
CHORDATA.

Animals possessing the following structural features: (1) a noto-
chord, a cylindrical rod lying along the mid-dorsal line of the digestive
tube, from the dorsal wall of which it has arisen, and ventral to the
central nervous system; (2) a pharyngeal respiratory apparatus consist-
ing of paired gill slits in the wall of the pharynx, which place that struc-
ture in communication with the exterior; and (3) a tubular, dorsal central
nervous system. In the air-breathing chordates, the notochord and the
gill slits are present only in the embryo, and in the adult are replaced by
the spinal column and the lungs.

The phylum contains about 37,000 species, of which over 35,000 are
vertebrates, grouped in 4 subphyla.

History.— This phylum was formed in 1874 by Haeckel as a result
of the epoch-making studies of Kowalevsky of Balanoglossus, ascidians,
and Amphioxus in the preceding decade.

Key to the subphyla of Chordata:
Oj Body (in the American species) long and worm-like.
a, Body not worm-like. L ENTEEOPNEUSTA (Hemichordata)

&! Body more or less sac-shaped 2. TUNICATA ( Urochordata)

6, Body lanceolate 3. LEPTOCAEDIA (Cephalochordata)

6a Vertebrates (not included in this book) 4. VEBTEBBATA

SUBPHYLUM 1. ENTEEOPNEUSTA.* (HEMICHOKDATA.)

Chordata in which the notochord consists of a hollow, dorsal projec-
tion of the anterior portion of the digestive tract (Fig. 996,13). The
body is unsegmented and soft in texture, and is composed of three por-
tions, the preoral lobe or proboscis (1), the collar (2), and the trunk (3).
The subphylum is composed of two orders, the Balanoglossida and the
Cephalodiscida, the latter order containing a very few species of marine
and largely deep-sea animals which are not found near our coasts.

* See "Les'Procordes," by Delage et He>ouard, Traite de Zool. Coner, Vol. 8,
1898. "The Development of Balanoglossus," by W. Bateson, Quart. Jour. Mic. Scl.,
Vols. 24-20, 1884-1886. "Growth and Development of Balanoglossus," by T. H.
Morgan, Jour. Morph., Vol. 5, p. 407, 1891. "Die Enteropneusten des Golfes von
Neapel," etc., by J. W. Spengel, Fauna and Flora, etc., 1893. "Die Benennung d.
Enteropneustengattungen," by same, Zool. Jabrb., System. Ab., Vol. 16, p. 219, 1901.
•'Hemichordata," Camb. Nat. Hist., 1904.

652

BALANOGLOSSIDA 653

History.— This group was first formed by Gegenbaur in 1870, who
placed it among the worms. When, however, the fundamental researches
of Kowalevsky became known and their significance appreciated the
relationship of the group to the Tunicata and Amphioxus was universally
recognized, and in 1884 it was brought under the Chordata by Bateson,
who at the same time proposed the name Hemichorda for it.

ORDER BALANOGLOSSIDA.

Elongated, worm-like Enteropneusta, which are often common on sand
flats. The proboscis is a cylindrical or ovoid structure joined with the collar
by a narrow neck. It contains a portion of the coelom which opens to the
outside by a dorsal pore (5), or in some cases by two; the collar also
contains two similar cavities, each with its pore. The trunk has an
extensive crelom in the form of

a pair of elongated cavities be- ^ "L~3 "O-Jk^J) { Y 8
tween which lies the digestive
tract (9), supported by a dor-
sal and a ventral longitudinal

mesentery. This tract is straight Fig. 996 — Diagram of a longitudinal sec-

tion of Balanoglossus (Shipley and Mac-

and extends from the mouth at Bride). 1, proboscis; 2, collar; 3, trunk;

4, heart ; 5, proboscis pore ; 6, nervous

the anterior end Of the collar system ; 7, dorsal blood vessel ; 8, bran-
chial region of intestinal tract ; 9, pharyn-

to the anus at the hinder end geal region; 10, gill slits; ll, ventral

blood vessel; 12, mouth; 13, notochord.

of the body: from its anterior

end a dorsal finger-shaped diverticulum (13), which represents the
notochord, extends forwards into the proboscis. The entire anterior
portion of the intestinal tract is placed in direct communication with
the exterior by a series of paired gill slits (10), back of which in certain
genera is a series of paired liver sacs which show conspicuously on the
outer surface of the body. A dorsal (7) and a ventral (11) blood ves-
sel accompanies the intestine, the former of which passes above the
notochord and ends in a sinus (4) situated in the collar and proboscis.
The nervous system is mostly sub-epithelial and diffuse. Mid-dorsally in
the collar and mid-ventrally in the trunk, however, are definite aggrega-
tions of nerve cells and fibers which are joined by a ring nerve just
behind the collar. The portion of the dorsal strand (6) in the collar is
tubular in shape and distinct from the outer epithelium and arises as a
neural canal, like the central nervous system of vertebrates: in certain
genera it is still joined with the outer epithelium by a series of median
nerves called nerve roots.

The sexes are separate, the gonads appearing as paired pouches along
the branchial region and back of it, each pouch opening to the outside

654 CHOEDATA

by a separate pore. The sexes often differ from each other in color.
The development is a metamorphosis, the characteristic larva, which is
called the tornaria, resembling the larvae of the echinoderms in form
and structure. This larva is not present, however, in Balanoglossus
aurantiacus, one of the most familiar American forms.

The American Balanoglossida live mostly in shallow water, in the
sand and mud, in which they burrow with aid of the proboscis. The
animals leave a coiled mass of sand held together by mucous on the
surface of the sand, which indicates the presence of the burrow ; they also
give out a disagreeable odor. They were first described by Eschscholtz in
1825, who put them in the genus Ptychodera, while Delle Chiaje in 1829
gave them the generic name Balanoglossus, which has been the familiar
name of the animals ever since. About 25 species are known, which are
grouped in 4 families.

Key to the American families of Balanoglossida:

<ii Liver sacs present 1. PTYCHODEBIDAE

0, Liver sacs absent 2. HABBIMANIIDAE

FAMILY 1. PTYCHODEEIDAE.

Paired liver sacs present behind the gill slits; chitinous rods sup-
porting the gill arches joined by connecting bars (synapticula) ; central
nervous system with nerve roots: 3 genera.

1. PTYCHODERA Eschscholtz. Gill openings to outside are long
slits; a pair of longitudinal dorsal wing-like lobes (genital wings)
present in the genital region: 10 species.

P. biminiensis Willey. Body large and finger-thick; proboscis
short: Bahamas.

2. BALANOGLOSSUS Delle Chiaje. Gill openings to outside are small
pores; proboscis short, with paired pores; medial gonads present: 5
species.

B. anrantiacus (Girard) (B. brooksii Bateson). Length 15 cm. or
more, sometimes a meter; color bright purplish or greenish: North and
South Carolina.

B. jamaicensis Willey. Body large, with transverse red bands:
Jamaica.

FAMILY 2. HABBIMANIIDAE.

Liver sacs, synapticula, and nerve roots absent: 2 genera.
1. DOLICHOGLOSSTJS Spengel. Proboscis long and with but one pore ;
medial gonads absent: 5 species.

TUNICATA

655

Fig. 997 — Dolicho-
glossus kowalevskyi
(Shipley and Mac-
Bride). Explanations
as in Fig. 996.

D. kowalevskyi* (A. Agassiz) (Fig. 997). Length 15 cm. or more;
color of proboscis pinkish-yellow; collar same color but darker; body
orange yellow: Massachusetts Bay to Beaufort, N. C.; often common
on clean sand flats.

D. pusillus Ritter. Length 20 cm. or more; color orange: southern
California.

2. HAHRIMANIA Ritter. Proboscis short, with 2
pores: 1 species.

H. maculosa Rit. Length 10 cm.; proboscis 13
mm., collar 4 mm., abdomen 89 mm. long; color dark
grayish-green; proboscis mottled: southern Califor-
nia; often common.

i\tixrz;::."+^

SUBPHYLUM 2. TUNICATA.f
(UEOCHOEDATA.)

Degenerate Chordata in most of
which the body of the adult is more
or less cylindrical or globular in
shape and is encased in a character-
istic cuticular covering called the tunic (Fig. 998, 7). This tunic is
secreted by the underlying epidermal cells, but in most tunicates differs
from a typical cuticula in that it is composed largely of cellulose and
contains also mesenchyme cells, which have migrated into it, and also
blood spaces. Immediately beneath the tunic is a second very definite
structure called the mantle (11), which is a firm, composite tissue made
up of connective tissue fibers and enclosing muscles and blood vessels.
Very characteristic are the large pharynx, or branchial sac, and the
endostyle. The former (8) is the anterior portion of the digestive tract
and occupies the greater portion of the body. The mouth leads into it,
and through the openings in its walls the respiratory water streams
either directly to the outside, as in the Larvacea, or, as in the other
tunicates, into the large cloacal or peribranchial space (Fig. 999,10),
which communicates with the outside through the cloacal aperture. The
endostyle (6) is a glandular, ciliated groove which lies in the mid-ventral

* See "The History of Balanoglossus and Tornaria," by A. Agassiz, Mem. Amer.
Acad. Arts and Sci., Vol. 9, p. 421, 1873.

t See "Description of Some Imperfectly Known and New Ascadians from New
England," by A. B. Verrill, Am. Jour. Sci. and Arts, 3rd ser., Vol. 1, 1871. "The
Invert, of Vineyard Sound," Rep. of U. S. Fish. Com., 1873. "A Revised Class, of
Tunicata," by W. A. Herdman, Jour. Linn. Soc. Zool., Vol. 23, p. 558, 1891.
"Tunicata," by O. Seellger and R. Hartmayer, Bronn's Klass. u. Ord. des Thierr.,
1895-1911. "The Pelagic Tunicata of the San Diego Region, excepting the Larvacea,"
by W. E. Ritter, U. of Cal. Pub. Zool., Vol. 2, p. 51, 1905. "The Pelagic Tunicata," by
W. E. Ritter and E. S. Byxbee, Mem. Mus. Comp. Zool., Vol. 26, 1905.

656

CHOEDATA

line of the pharynx, the secretions of which serve to entangle the minute
organisms which form the food of the animals, and the action of whose
cilia carries these forward to the ciliated peripharyngeal band (Fig.
998,5) which surrounds the anterior end of the pharynx. This band
the food dorsally to the dorsal lamina (9), a ciliated band in the
mid-dorsal line, along which it is car-
ried to the opening of the oesophagus
at the inner end of the pharynx. The
short CBSOphagus joins the pharynx
with the stomach (15), from which the
intestine passes to the anal opening
into the cloacal space.

The heart (12) is ventral in posi-
tion and lies in a pericardial space,
which alone represents ,the only part
of the coelom in the adult. The con-
tractions of the heart change their
direction regularly, passing first for a
time from one end of the heart to the
other and then after a moment of rest
in the opposite direction, a peculiarity
which occurs only in tunicates. The
blood circulates mainly in spaces in the
mantle and the tunic and in the walls
of the branchial sac. The nervous sys-
tem consists, first, of a simple dorsal ganglion (4) which lies in the
mantle near the mouth, and, second, of nerves which radiate from it.
Simple eyes and tactile organs are present in many species. Tunicates
are mostly hermaphroditic, the gonads being
either single or paired and the genital ducts
opening into the cloacal chamber. Asexual
reproduction is very general, and in many
species may lead to the formation of colo-
nies. The adult structure of the Larvacea
as well as the embryonic and larval structure
of the Ascidiacea present many points of
resemblance to Amphioxus and the lower
vertebrates, indicating a relationship between
these animals and tunicates. This resem-
blance consists in the main in the presence of
a tubular, dorsal central nervous system, a notochord, a ventral heart,
and the pharyngeal respiration.

Fig. 998 — Diagram of a simple
ascidian (Boas). 1, mouth ; 2, cloa-
cal opening ; 3, subneural gland ; 4,
principal ganglion ; 5, peribranchial
ridge ; 6, endostyle ; 7, tunic ; 8,
pharynx ; 9, dorsal lamina ; 10,
peribranchial space ; 11, mantle ;
12, heart; 13, anus; 14, intes-
tine ; 15, stomach ; 16, testis ; 17,
ovary.

Fig. 999 — Diagram of a
cross section of an ascidian
(Boas). Explanations as in
Fig. 998.

TUNICATA

657

History.— Ascidians have been known since the time of Aristotle,
but it was not until the first years of the last century that Cuvier, Savigny,
and Lamarck first accurately described them. The name Tunicata was
introduced by the latter author in 1816. Salpa was first described by
Forskal in 1775, and in 1819 its interesting life history was first made
known by the German poet Chamisso. Steenstrup in 1842 more fully
described this and first called it an alternation of generations. It was
in 1826 that Milne-Edwards discovered and correctly interpreted the
ascidian tadpole, while Kowalevsky in 1866 and 1871 published his cele-
brated memoirs giving the complete embryology of the animals and dem-
onstrating the common relationship of tunicates and vertebrates. Up to
that time the tunicates were almost universally classified with mollusks.
Milne-Edwards had, however, in 1841 placed them in the Molluscoidea,
a phylum he created to contain them and the Bryozoa.

Tunicates are all marine animals, the ascidians being sessile and the
others pelagic. The number of species is about 1,300, which are grouped
in 3 classes.

Key to the classes of Tunicata.

dj Pelagic animals.
Z>! Animals minute and with a

long tail 1. LABVACEA

6a Animals not minute, and more
or less cylindrical or flat-
tened 2. THALIACEA

oa Sessile (except the Pyrosomi-
dae), sac-shaped animals..
3. ASCIDIACEA

CLASS 1. LARVACEA.*

The appendicularians (Fig.
1,000). Minute, transparent,
free-swimming tunicates in which
the body consists of a trunk (2)
and a long tail (10), having es-
sentially the same organization
as the larval ascidian. The trunk
contains the large pharynx and
the viscera. The tail is a solid
structure, the axis of which is
structure is the principal nerve
muscle band. The tail is twisted

Fig. 1,000 — Diagram of an appendicu-
larian (Oikopleura) (Delage et H6rouard).

I, mouth ; 2, trunk ; 3, pharynx ; 4, anus ;
5, stigmata ; 6, heart ; 7, stomach ; 8,
ovary ; 9, testis ; 10, basal portion of tail ;

II, notochord ; 12, principal nerve ; 13,
endostyle.

the notochord (11) ; dorsal to this
(12) and on each side of it a broad
90°, so that its dorsal side lies at the

* "fitudes sur les Appendiculaires du d€troit de Messine," by H. Fol, M€m. Soc.
Phys. Hist, nat., G«neve, Vol. 21, 1872,

658 CHOEDATA

left and its ventral side at the right. The mouth (1) is at the forward
end and opens into the pharynx (3), from which the two ventro-lateral
stigmata (5) open directly to the outside back of the anus, there being
no peribranchial cavity and no cloacal pore. Most species are her-
maphroditic, the gonads lying in the hinder part
of the trunk. The tunic or "house" is a trans-
parent envelope of large size, being sometimes
many times the size of the body, which is secreted
by certain large ectoderm cells called oikoplasts.
Within this tunic (Fig. 1,001) the animal can move
about freely : it is shed periodically and often, and

Fig. 1,001— Appen- contains no cellulose.
dicularians in their

H6?ouaSrd)DelAgeoifco? The aPPendicularians are found in all seas,

being usually more numerous at a distance from
the continents. Most species live near the surface,
but a few have been obtained at considerable depths.

The class contains 2 families and more than 40 species.

Key to the families of Larvacea:

o, Endostyle present ................................ 1. APPENDICULABIIDAE

a, Endostyle absent ........................... . ....... 2. KOWALEVSKIIDAE

FAMILY 1. APPENDICULABIIDAE.

Pharynx with endostyle, from the forward end of which peripharyn-
geal ridges run dorsally and posteriorly and unite near the oesophageal
opening; heart present: 8 genera and over 30 species.

Key to the genera of Appendiculariidae here described:

G! Trunk short and more or less oval.
&! Tail about twice as long as trunk .................... 1. APPENDICULABIA

6a Tail several times as long as trunk ....................... 2. OIKOPLEUBA

ca Trunk very long ........................................ 3. FBITILLABIA

1. APPENDICULARIA Fol. Trunk short, compressed anteriorly ; tail 2 or
3 times as long as broad and twice as long as the trunk ; endostyle straight
or slightly curved ; intestine turned to the right and bent round the very
large vesicular rectum; anus on the right; ovary round, surrounded by
the horseshoe-shaped testis : 1 certain and several uncertain species.

A. sicula Fol. (Fig. 1,001, B) . Mediterranean Sea and Atlantic Ocean.
A. longicauda Vogt. Long Island Sound to Massachusetts Bay.

2. OIKOPLEURA Mertens (Fig. 1,000). Trunk oval; tail from 2 to
6 times as long as broad and from 2 to 4 times as long as the trunk;
digestive tract very large, with a curved oesophagus and a bilobed stom-
ach; gonads very large; testis usually paired and one on each side of
the median ovary: 14 species.

TUNICATA

659

O. flabellum Huxley (0. huxleyi Ritter). Length up to 12 mm., of
which 10 mm. is tail: Pacific and Atlantic Oceans.

O. cophocerca Gegenbauer (Fig. 1,001, A). Length 11 mm., of
which 8 mm. is tail; a long double row of cells on right side of tail:
Mediterranean Sea.

3. FBITILLARIA Fol. Trunk very long, usually constricted near the
middle and with an extensive dorsal ectodermal fold which covers it
like a cowl; tail about 1.5 times as long as the trunk and 2.5 times as

Fig. 1,002

Fig. 1,003

Fig. 1,002— Fritillaria furcata (Fol). Explanations as in Fig. 1,000.
Fig. 1,003 — Kowalevskia tennis (Fol).

long as broad; endostyle bent; tunic absent or not well developed;
digestive tract small, confined to the middle of the trunk; ovary spher-
ical, testis large and saccular, in hinder part of trunk, both usually
single: about 8 species.

F. furcata (Vogt) (Fig. 1,002). With long posterior processes;
tail forked at its extremity: Mediterranean Sea; North Atlantic.

FAMILY 2. KOWALEVSKIIDAE.

Pharynx without endostyle and periphryngeal ridges; heart absent:
1 genus and 2 species.

KOWALEVSKIA Fol. Trunk elongate, cylindrical ; tail about 7 times
as long as trunk 'and lanceolate, running to a point behind; tunic very
thin and delicate; oesophagus very wide; ovary spherical; testes reni-
fonn: 2 species.

K. tenuis Fol. (Fig. 1,003). Mediterranean Sea and Atlantic Ocean.

660

CHORDATA

CLASS 2. THALIACEA.

The salpas (Fig. 1,004). Pelagic, transparent tunicates, more or
less cylindrical in shape, with a large oral opening (1) at one end of
the body and a cloacal opening (12) at the other. The body wall con-
sists of a cellulose tunic (4) and a mantle, the latter containing a
number of conspicuous, more or less ring-shaped muscle bands (11), by
the contraction of which water is expelled from the cloacal opening as
the animal moves forwards. The cavity of the body is divided by a

respiratory parti-

_y* ;( a* tion (3) containing

J|p!3£^*<^ slits or stigmata

(Doliolum) or con-
sisting simply of a
ciliated bar (Salpa),
into two chambers,
the anterior or
pharyngeal (5) and

a

Fig. 1,004 — Diagram of a salpa (Cambridge Natural
History). 1, mouth; 2, brain; 3, respiratory partition;
4, test; 5, pharynx: 6, endostyle; 7, heart; 8, nucleus;

9, cloacal cavity ; 10, ovary ; 11, muscle bands ; 12, cloa- 4-un r^efo™™* n-n «1«
cal opening; 13, peripharyngeal ridge ; 14, dorsal lamina ; tne posterior or Clo-
15, salpa chain. acal (9), t h r o u g h

which the water streams. Endostyle (6) and dorsal lamina (14) are
present. The principal viscera lie embedded in the mantle on the ventral
side of the body (8), forming there in many species a small, compact,
usually highly colored mass called the nucleus. The principal ganglion
(2) lies in the dorsal wall of the pharyngeal chamber. Immediately
above it in Salpa is a simple eye. Beneath the ganglion is a subneural
gland.

The Thaliacea have what is usually called an alternation of genera-
tions, a solitary generation alternating with an aggregated one, although
in Salpa at least it is not strictly so. In the solitary form of Salpa a
ventral, posterior stolon arises, on which buds appear which are destined
to become the aggregated generation. Near the base of the stolon the
solitary individual bears a mass of germ cells, some of which are received
by the buds as they arise. Thus the buds, and the animals of the aggre-
gated generation they grow into, serve merely as nurses for the embryos
arising from these germs which have been received from the solitary
individual. The aggregated individuals form the Salpa chain and often
remain attached together long after they have left the parent. The class
contains about 40 species, grouped in 2 orders.

Key to the orders of Thaliacea:

di Respiratory partition plate-like 1. MULTISTIGMATEA

oa Respiratory partition rod-like 2. ASTIGMATEA

TUNICATA 661

ORDER 1. MULTISTIGMATEA.*

Body barrel-shaped, with a thin tunic and with muscle bands form-
ing complete rings; openings lobed and at opposite ends of the body;
respiratory partition with 2 rows of stigmata; life history including 3
types of asexually produced individuals and a fourth type arising from
a fertilized egg: 3 genera.

DOLIOLUM Quoy and Gaimard. Sexual generation with 8 muscle
bands and with 12 oral and 10 cloacal lobes; first asexual generation,
with 9 muscle bands and 10 oral and 12 cloacal lobes. From the hinder
end of this individual grow a dorsal protuberance and a ventral stolon;
the buds, originating on the latter, migrate to the former, which be-
comes long and tail-like and bears 5 rows of buds, of which the median
row becomes detached to form the next asexual generation. The animals
of this generation are similar to the sexual generation except that they
have no sexual organs and have a ventral stolon which produces buds
which become detached and grow into the sexual generation. About 13
species are known, mostly in the warmer oceans.

D. denticulatum Quoy and Gaim. Sexual generation with a bent
respiratory partition which has about 40 stigmata on each side ; digestive
canal straight ; length 3 mm. : Atlantic Ocean and Mediterranean Sea.

ORDER 2. ASTIGMATEA.f

Body usually somewhat flattened dorsoventrally, with terminal or
subterminal oral and cloacal openings; tunic thick; muscle bands do
not form complete rings in many species; respiratory partition reduced
to a ciliated bar which runs diagonally from the dorsal body wall to the
O3sophagus in the ventral; life history including 2 types of individuals,
a solitary and an aggregated, which alternate with each other: 2 genera
and about 25 species.

Key to the genera of Astigmatea:

o, Nucleus usually present, when absent muscle bands numerous; salpa

chain straight 1. SALPA

o. No nucleus present ; salpa chain often circular 2. CYCLOSALPA

1. SALPA Forskal. Digestive tube usually bent on itself and con-
tained in the nucleus; 1 to 5 embryos formed; chain double: about 18
species; in all the warmer seas.

* See "Cyclomyaria et Pyrosomida," by G. Neumann, Das Tierreich, 1913.
t See "The Genus Salpa," by W. K. Brooks and M. M. Metcalf, Mem. Johns Hop.
Univ., Vol. 2, 1893. "Desmomyarla," by J. E. W. Ihle, Das Tierreich, 1912.

CHOEDATA

—IS

Fig. 1,005 — Salpa fusiformis. A, ag-
gregated form ; B, solitary form (Cam-
bridge Natural History). Explanations
as in Fig. 1,004.

S. fusiformis Cuvier (Fig. 1,005). Solitary form (8. fusiformis

Cuv.) a flattened cylinder and with
9 muscle bands and 2 short spinose
projections at hinder end and 4 to 8
cm. long; aggregated form (S. run-
cinata Chamisso) with 6 muscle
bands, elliptical and 14 to 60 mm.
long: cosmopolitan.

S. (Thalia Blumenbach) demo-
cratica Forsk. (Salpa caboti Desor)
(Fig. 1,006). Solitary form (S.
democratica Forsk.) ovoid, with 2
long posterior projections and up to
24 mm. long; aggregated form (S.
mucronata Forsk.) ovoid, pointed be-
hind and up to 15 mm. long; nucleus
blue in both forms: cosmopolitan;

often appearing in immense numbers off the coast of New England;

the commonest species.

S. (Pegea Savigny) confffiderata Forsk. Soli-
tary form short and wide, pointed behind; 4

muscles, which are confined to the back; length 4

to 12 cm.; aggregate form (S. scutigera Cuv.)

cylindrical, often reddish in color, with 4 muscles ;

length 7 to 15 cm. : cosmopolitan ; aggregate form

often common ; solitary form very rare.

S. (Jasis Lahille) zonaria (Pallas). Solitary

form elongate, very firm and hard, with 5 very

broad muscles and 1 narrower posterior muscle

on the dorsal surface, and up to 6 cm. long; ag-
gregate form elongate, ovoid, pointed behind,

about 24 mm. long; very firm: in all warmer

seas; Woods Hole; Arctic Seas.

2. CYCLOSALPA Blainville. Digestive tube

straight or curved, running antero-posteriorly

and not coiled up to form a nucleus; salpa chain

often circular; in other respects like Salpa: 6

species.

C. affinis (Chamisso). Aggregated form about 7 cm. long, with ventral

hatchet-shaped organ of attachment ; apertures terminal ; solitary form 5

to 10 cm. long, with no longitudinal muscles: Mediterranean; Atlantic

and Pacific Oceans ; often very plentiful.

Fig. 1,006 — Salpa de.
mocratica — solitary form
(Vogt and Jung). Expla^
nations as in Fig. 1,004.

TUNICATA 663

CLASS 3. ASCIDIACEA.*

The aseidians. Sac-shaped, mostly sessile and either simple or com-
pound tunicates with oral and cloacal openings usually placed near to-
gether, each at the end of a contractile projection called the siphon (Fig.
998). The cellulose tunic is usually thick and tough, but in some forms
it is gelatinous or transparent, and is often rough and warty on the
outside. Both openings can be closed by sphincter muscles and are often
provided with a number of sensory lobes bearing in some cases pigment
spots. The branchial sac (8) is very large and its entire wall is pierced
by more or less regular series of slits or stigmata, giving it a lattice-like
appearance. Its upper margin is surrounded by a circle of tentacles,
which thus lie just back of the mouth. Endostyle (6), peribranchial
band (5), and dorsal lamina (9) are present. On each side of the
branchial sac is the peribranchial space, into which the respiratory water
as well as the discharges from the genital and digestive organs are
poured, and which communicates with the outside through the cloacal
opening (Fig. 999,10). The oesophagus, stomach, and the short intestine
are either at the side of or beneath the branchial sac. The anus opens
into the peribranchial chamber near the cloaca or into the cloaca itself.
The principal ganglion (4) is situated between the two siphons in the
mantle and adjacent to it is the subneural gland (3), which is supposed
to be homologous to the hypophysis of vertebrates. A duct joins this
gland with the pharynx, the opening being at the end of a projection
called the dorsal tubercle. A ductless kidney or scattered renal cells in
the bend of the intestine contain uric acid crystals.

Aseidians are hermaphroditic, the gonads lying close together. From
the egg is hatched a long-tailed larva which has the appearance and gen-
eral structure of an appendicularian. This larva attaches itself to some
fixed object by three papillae at the forward end, and a complex meta-
morphosis proceeds, during which the tail is absorbed, the peribranchial
chamber develops, and the body assumes the spherical or cylindrical shape
of the adult.

Aseidians are either simple or colonial and with the exception of the
Pyrosomidae are all sessile, being attached usually to rocks or seaweed.
The colonial forms arise by a process of budding from one another and
form incrusting or erect masses on shells, seaweed, etc. Several species
are used for food, large numbers being brought into the fish markets of

* See "Some Ascidlans from Puget Sound," by W. E. Rltter, Ann. N. Y. Acad. Scl.,
Vol. 12, p. 589, 1909. "The Aseidians of Bermuda," by W. G. Van Name, Trans.
Conn. Acad., Vol. 11, p. 325, 1902. "Mosaic Development in Ascidian Eggs," by
E. G. Conklin, Jour. Ex. Zool., II, p. 145, 1905. "The Simple Aseidians from the
North Eastern Pacific," etc., by W. E. Ritter, Proc. U. S. Nat. Mus., Vol. 45.
p. 427, 1913.

664 CHORDATA

Marseilles and other Mediterranean cities. Over 1,200 species of ascidians
are known, grouped in 2 or 3 orders.
Key to the orders of Ascidiacea:

Oj Sessile ascidians.
fcj Simple ascidians, or forms loosely connected by a stolon.

1. ASCIDIAE SIMPLICE8

6, Colonial ascidians, forming compact masses 2. ASCIDIAE GOMPOSITAE

of Pelagic ascidians 3. ASCIDIAE LUCIAE

ORDER 1. ASCIDIAE SIMPLICES.*

Solitary aseidians, or when colonial always loosely connected and
with the tunics separate and distinct, and not fused together; never free-
swimming: about 4 families and over 500 species.

Key to the families of Ascidiae simplices:

c, Individuals not permanently joined together.
61 Body more or less spherical and often stalked.

«! Colors dull ; surface often incrusted with sand 1. MOLOULIDAE

c, Colors often bright, surface usually free from sand. . , 2. CYNTHIIDAK

I, Body cylindrical, elongate and not stalked 3. ASCIDIIDAE

a, Individuals joined by creeping stolons 4. CLAVELINIDAB

FAMILY 1. MOLGULIDAE.

Body spheroidal, seldom stalked, with dull, usually gray colors and
often incrusted with sand or mud; mouth with 6 outer lobes and with
branched inner tentacles; cloaca with 4 lobes; intestine usually on the
left; kidney and heart on the right side of the branchial sac; reproductive
organs either paired or not, in latter case either on right or left side;
animals solitary, often in sand or mud: about 14 genera and over 100
species.

Key to the genera of Molgulidae here described:

ot Body not stalked.

6, Branchial sac with longitudinal bars 1. MOLQULA

b, No such bars.

c, No corkscrew-shaped inf undibula on branchial sac 2. EUQYBA

c, Such inf undibula present 3. BOSTBICHOBBANCHUS

o, Body stalked 4. RHIZOMOLOULA

1. MOLGTJLA Forbes. Siphons usually long and very contractile;
tunic thin and more or less transparent, although often incrusted with
sand and dirt; gonads paired and usually hermaphroditic; branchial sac
large, with 6 or 7 longitudinal folds or bars: cosmopolitan; 50 or more
species, some of which are not fixed, 10 American.

• See "Simple Ascidians of the Coast of New England," etc., by W. Van Name,
Proc. Host. Soc. Nat. Hist., Vol. 34, 1912.

TUNICATA 665

Key to the species of Molgula here described:

G! Siphons contiguous at the base.

bt Siphons not swollen at the base M. MANHATTENSIS

6, Siphons swollen at the base M. PELLUCIDA

a. Siphons not contiguous.

&! Siphons short M. ARENATA

&a Siphons long M. PAPILLOSA

M. manhattensis (DeKay) (Fig. 1,007). Body globose or ovoid;
external surface corrugated, usually covered with foreign matter;
siphons contiguous; length 25 mm.: on rocks or eel grass,
often in clusters, in shallow water below low tide lines;
from North Carolina to Casco Bay; abundant.

M. arenata Stimpson. Body globose, often com-
pressed, covered with sand which adheres tightly; siphons
short, not contiguous ; length 20 mm. : on sand and gravel Fig
in shallow water; in Long Island and Vineyard Sounds, manhatiensis

M. pellucida Verrill. Body globose, with a smooth, (Verriii).
translucent tunic to which sand does not adhere; siphons contiguous,
long and diverging and swollen at the base ; length 25 mm. : on sand in
shallow water from North Carolina to Massachusetts Bay.

M. papillosa Verr. Body globose, often compressed, covered with
sand or dirt; siphons not contiguous, long, and diverging; length 10
mm.: on sand and gravel in 10 to 20 fathoms; from Vineyard Sound
northwards; common towards the north.

2. EUGYRA Alder and Hancock. Branchial sac without longitu-
dinal bars; a single hermaphroditic gonad present, which is on the left
in the bend of the intestine: 8 species; in shallow water.

E. pilularis Verr. (Fig. 1,008). Body globose, covered with mud
or fine sand; siphons close together, slender, and as long as the body
when extended ; diameter up to 8 mm. : in 10 to 20 fathoms
from Vineyard Sound northwards, in mud or fine sand,
where it is locomotory; often abundant.

3. BOSTRICHOBRANCHUS Traustedt. Like Eugyra but
with corkscrew-shaped infundibula in the meshes of the
branchial sac : 2 species.

B. molguloides Metcalf. Body 3 cm. in diameter and
not attached: Woods Hole; on muddy bottoms.
4. RHIZOMOLGULA Ritter. Body ovoid, prolonged posteriorly in a
stalk which may be as long as or longer than the body and ends in a
number of root-like branches; kidney and the single gonads on the left
side : 4 species ; in North Pacific and Atlantic Oceans.

R. ritteri Hartmeyer. Body globose, wider than long, 8 mm. long
with a stalk of same length : Baffin Bay ; in shallow water.

666 CHORDATA

FAMILY 2. CYNTHIIDAE.

Body always attached, spherical or elongate, with a tough leathery
tunic which is opaque, often brightly colored, and usually not covered
with sand; siphons short and usually four-lobed; inner tentacles either
simple or branched; branchial sac large, with 4 or more longitudinal
folds or bars on each side; intestine on the left side; distinct kidney
absent, its place taken by scattered renal cells; gonads hermaphroditic:
several hundred species.

Key to the genera of Cynthiidae here described:

a± Body not stalked or with a short stalk.
&! Oral tentacles simple and filiform ....... . .................... 1. STYELA

I, Oral tentacles branched ................................... 2. CYNTHIA

ca Body with a long stalk .................................... 3. BOLTENIA

1. STYELA Fleming. Body sessile; branchial sac with not more
than 4 ridges on each side; tentacles simple and filiform: cosmopolitan;
over 75 species.

S. partita (Stimpson) (S. aggregata var. americana Metcalf) (Fig.

1,009). Body somewhat flattened and attached by a broad base; surface
not sulcated, hard, wrinkled, dark brown in
color; siphons square, elevated, each aperture
marked by alternating triangles of white and
purple; length 25 mm.; breadth 12 mm.: Mas-

Fig. 1,009 — styela partita sachusetts Bay to North Carolina ; in shallow
water; common, occurring in groups.

2. CYNTHIA Savigny. Body sometimes with a short stalk ; branchial
sac with 6 to 12 longitudinal ridges on each side; dorsal lamina a ser-
rate or fringed membrane; tentacles branched; gonad paired: 100
species.

C. castaneiformis Drasche. Peduncle about as long as body but
variable in length; body more or less globose in form and hirsute;
orifices prominent; tentacles 50; branchial
ridges 8 on a side; length 35 mm.: Puget
Sound and southerly; common.

C. carnea Verrill (Fig. 1,010). Body flat

and disc-like, oval, and deep red in color, at- FI&- 1>01^t^fia carnea
tached by a very broad base; siphons small;

length 12 mm.: Martha's Vineyard to Labrador; in shallow water; often
very common.

C. pyrifonnis (Rathke). Sea peach. Body globose or elliptical,
often attached by a narrow base; surface velvety and pink, red, or
yellowish in color; length 75 mm. or less; width 30 mm.; siphons cylin-

TUNICATA

667

drical, large, and prominent: Massachusetts Bay to Greenland, in clear,
shallow water; common towards the north; Norway.

0. superba Ritter. Body large, bright red in color, pear-shaped,
with the broad end at the base, 15 cm. long and 6.5 cm. thick; siphons
prominent, not contiguous: Puget Sound; rare.

0. (Halocynthia Verr.) echinata (L.). Body globose; surface
wrinkled, covered with fine fibers and elevated tubercles, each bearing
a stellate cluster of about 6 yellow bristles; diameter 25
mm.; color red: Martha's Vineyard to Greenland; in
shallow water; common towards the north; Europe.

3. BOLTENIA Savigny. Body globose or elliptical and
attached by a long stalk which proceeds from the antero-
ventral side of the body; orifices not terminal but lateral
in position, each being provided with 4 lobes; oral ten-
tacles branched; more than 8 longitudinal ridges in
branchial sac: about a dozen species; in the colder seas.

B. mbra Stimpson. Sea potato (Fig. 1,011). Body
slightly compressed and tapering to the slender stem;
color red ; surface rough ; length of body 4 cm., of stem 26
cm.: Cape Cod northwards, in 2 to 14 fathoms; abundant.

FAMILY 3. ASCIDIIDAE.

Fig. 1,011

Bolteniarubra

(Gould).

Body more or less cylindrical, with a gelatinous,
transparent tunic; openings lobed; oral tentacles simple;
branchial sac without well-developed longitudinal bars; gonads her-
maphroditic and unpaired: species numerous; about 10 genera.

1. ASCIDIA L. Body elongate; branchial sac extending to the base
with the intestine on its left side; oral opening with 8 and cloacal
opening with 6 lobes: numerous species.

A. atra Lesueur (A. nigra Savigny). Body ovate,
elongate, with abundant blue-black pigment in the tunic
and many internal organs; length 7 cm.; diameter
3 cm.: Bermuda; West Indies.

2. CIONA Savigny. Body cylindrical and elongate;
siphons more or less extended, oral siphon with 8 and
cloacal siphon with 6 lobes; intestine beneath the bran-
chial sac, which does not extend to the base : 10 species.
C. intestinalis (L.) (C. tenella Stimpson) (Fig. 1,012). Body more
or less transparent, 10 cm. long or less and 20 mm. wide, adhering by the
base, sometimes yellowish in color: Long Island Sound to Labrador, on
stones, shells, etc. ; common towards the north.

Fig. 1,012

Ciona intestinalia

(Gould).

668 CHOEDATA

FAMILY 4. CLAVELINIDAE:

Body elongated and joined by means of creeping stolons with other
individuals, forming thus a branched colony with a common blood
system, or rarely embedded in a common gelatinous tunic; apertures
simple, rarely lobed: about 8 genera and 28 species.

1. CLAVELINA Savigny. Zooids elongate, made up of 2 regions, a
thorax and an abdomen, joined by stolons with one another; apertures
simple: about 8 species.

C. oblonga Herdman. Zooids club-shaped, 30 mm. long or less;
tunic thick and transparent; branchial sac with about 15 rows of stig-
mata ; tentacles about 20 in number, short and stout : Bermuda ; common.

2. PEROFHOBA Lister. Body compact and not composed of 2 re-
gions, the intestine being at the side of the branchial sac ; both apertures
six-lobed.

P. viridis Verrill. Body small, oval, 3 mm. long, greenish or yel-
lowish in color : Vineyard Sound ; common ; often covering piles, seaweed,
or stones near low-water mark.

ORDER 2. ASCIDIAE COMPOSITAE.*

Composite, colonial ascidians, the members of a colony being joined
by a common tunic and often possessing a common cloaca, and arising
from one another by a process of budding; individuals often elongate
and consisting of 2 or 3 distinct divisions, called thorax, abdomen, and
post-abdomen (Fig. 1,014) : about 7 families.

Key to the families of Ascidiae compositae here described:
<»! Body without division into thorax and abdomen ; mouth not lobed.

1. BOTBYLLIDAE

o. Body composed of 2 or 3 divisions ; mouth with usually 6 lobes.
&! Colony not mcrusting.

<?! Colony without common cloacal openings 2. DISTOMIDAE

c Colony with common cloacal openings 3. POLYCLINIDAK

fea Colony incrusting 4. DIDEMNIDAE

FAMILY 1. BOTRYLLIDAE.

Colony either thin and crust-like or thick and fleshy, consisting of
individuals in groups, each group with a common cloaca; no division
into thorax and abdomen; branchial sac without longitudinal folds,
usually with 3 inner longitudinal bars; male and female gonads sep-
arate, on both sides of body: 5 genera with about 80 species.

Key to the genera of Botryllidae here described:

«! Individuals in circular, star-shaped, or elliptical groups 1. BOTBYLLUB

c, Individuals not in regularly arranged groups 2. BOTBYLLOIDES

• See "Compound Ascidians of the Coast of New England," etc., by W. Van Name,
Proc. Bost. Soc. Nat. Hist., Vol. 34, 1910.

TUNICATA

669

1. BOTRYLLTJS Gaertner. Colony thin and crust-like and embedded
in a common gelatinous tunic, the individuals being in circular, stellate,
or elliptical groups, in each of which they are arranged radially around
a common cloacal opening; incurrent opening widely separated from
the cloacal and near the periphery of the group; oral tentacles not
branched and few in number: about 24 species; principally in North
Atlantic and Mediterranean, in shallow water.

B. schlosseri (Pallas) (B. gouldi Verrill) (Fig. 1,013). Colonies
massed thickly together on seaweed, stones, etc., forming gelatinous,
black or purplish incrustations sometimes 10 cm. or more in diameter, a
colony being made up of many groups, each group consisting of from
5 to 10 individuals and 3 to 6 mm. in diameter: Long Island Sound and
northwards; very common; Europe.

Fig. 1,013 — Botryllus schlosseri. A, a colony on a seaweed containing 7 groups
of individuals (Gould) ; B, diagram of a single group of individuals; C, diagram of
two individuals of a group with the common cloacal opening, the right-hand individual
in sagittal section (Delage and H6rouard). Explanations as in Fig. 998.

2. BOTRYLLOIDES Milne-Edwards. Colony thin and crust-like, the
individual animals lying perpendicular to the surface and usually not
arranged in definite groups; the individuals lie along cloacal canals
which meet and open to the outside through a common cloacal pore:
over 2 dozen species.

B. nigrum Herdman. Colony up to 7 cm. in diameter, very variable
in color, usually purplish or blackish; individuals about 1.5 mm. long:
Bermuda; in shallow water; common on stones and seaweed.

FAMILY 2. DISTOMIDAE.

Colony thick, sometimes stalked, usually embedded in a common
tunic; individuals consisting of thorax and abdomen, the viscera being
beneath the branchial sac, which is without internal longitudinal bars
or folds; openings each with 6 lobes: 10 genera, with about 80 species.

DISTOMA Gaertner. Colony thick and fleshy, with the individuals
often in groups; intestine very long; branchial sac short: about 20
species.

D. clarum Van Name. Colony jelly-like, transparent, 12 mm. in
width and half as thick ; individuals lying at all angles to surface, white

670

CHORDATA

in color with orange intestine: Bermuda; common along the shore and
on the reefs.

FAMILY 3. POLYCLINIDAE.

Colony variable in shape but usually massive, sometimes stalked,
and enclosed in a common tunic; individuals elongate, composed of 3
regions, sometimes in groups; incurrent opening
with 6 or 8 lobes ; budding by division of the post-
abdominal body region which contains the gonads,
the heart in the pericardium and the epicardium,
which is a tubular prolongation of the pharyngeal
sac (Fig. 1,014) : about 20 genera and over 150
species.

AMAROUCITTM Milne-Edwards. Colony usually
massive, more or less gelatinous or cartilaginous
in consistency; individuals very much elongated
and usually in irregular groups: about 60 species,
most of which occur in shallow water.

A. pellucidum (Leidy). Colonies large, com-
plex, consisting of many groups of elongate zooids,
each group having a common cloacal opening and
all enclosed in a common gelatinous, translucent
tunic; colony up to 15 cm. in diameter; separate
zooids up to 25 mm. long; stomach bright orange
in color: North Carolina to Vineyard Sound; very
common in shallow water.

A. stellatum Verrill. Colonies large, often in
form of thick vertical plates which may be 60 cm.
long, 15 cm. high, and 25 mm. thick, enclosed by a
common gelatinous tunic, and called "sea pork"
by fishermen; color pale bluish or pinkish; zooids
arranged in stellate clusters containing from 6 to
20 individuals each; branchial sac and intestine
orange : very common from North Carolina to Cape
Cod and northwards.
A. constellatum Verr. Colony thick, often incrusting, with a smooth
surface, forming hemispherical crusts on piles, rocks, etc.; color orange
or pink; zooids arranged in irregular stellate or elliptical groups: Long
Island and Vineyard Sounds and northwards.

FAMILY 4. DIDEMNIDAE.

Colony incrusting, sometimes thick and massive, and contained in a
common tunic, in which are calcareous spicules; zooids arranged in com-

"1

Fig. 1,014

Diagram of Amarou-
cium (Bronn). 18, tho-
rax ; 19, abdomen ; 20,
postabdomen ; 21,
blood space; 22, epi-
cardium, a prolonga-
tion of the pharyngeal
sac into the postabdo-
men. Other explana-
tions as in Fig. 998.

TUNICATA 671

plex branching systems of small size, with body composed of 2 portions ;
incurrent opening 6-lobed : 9 genera, with numerous species.

DIDEMNUM Girard. Colony usually thick, opaque, often leathery;
calcareous spicules stellate in form; zooids small, with 3 rows of stig-
mata in the branchial sac: numerous species.

D. orbiculatum Van Name. Colonies thin, 25 mm. wide and 2 mm.
thick, gray in color, with numerous spicules which tend to conceal the
zooids: common on the underside of stones near low water in Bermuda.

D. lutarium Van Name (Leptoclinum albidum Verrill; L. luteolum
Verr.). Colony forms a thin incrustation up to 30 cm. in diameter, cov-
ering stones, shells, etc., and white or pink in color, with an uneven
surface by reason of the numerous calcareous spicules present: Long
Island Sound to Labrador; common; in shallow water.

ORDER 3. ASCIDIAE LUCIAE.*

Animals colonial, free-swimming, and enclosed in a common tunic;
colony cylindrical, conical or flattened in shape with one open end;
zooids arranged in a single layer, perpendicular to the surface, the incur-
rent openings being on the outer and the
cloacal openings on the inner surface of
the cylindrical colony; projecting from
the outer surface are often long finger-
like processes of the tunic, and at the
forward end of the branchial sac of each
zooid are paired phosphorescent organs;

the colony swims with the closed end in Fig. 1,015 — Pyrosoma, atlanticum

(Cambridge Natural History),
advance as the result ot the streaming

of water out of the open end: 1 genus, the species of which are noted
for their brilliant phosphorescence.

PYROSOMA Peron. With the characters of the order; colony
cylindrical or flattened : 8 species, in tropical seas.

P. atlanticum Per. (Fig. 1,015). Colony conical, 3 or 4 cm. in
diameter, and 25 cm. or more in length, although usually much smaller;
color greenish, pinkish, or yellowish: in the tropical Atlantic.

SUBPHYLUM 3. LEPTOCARDIA.* ( CEPHALOCHOKDATA ;

AMPHIOXUS.)

Elongate, fish-shaped Chordata, in which the notochord extends the
entire length of the body. The body is laterally compressed and pointed

* See "Cyclomyaria et Pyrosomida," by G. Neumann, Das Tierreich, 1913.
t See "Amphioxus and the Ancestry of Vertebrates," by A. Willey, 1894. "A
Revision of the Genera and Species of the Branchiostomidae," by J. W. Kirkaldy,

672 CHOBDATA

at both ends, with conspicuous muscle segments (my;otomes) and a
dorso-ventral fin at the hinder end. There is no head, the mouth, which
is surrounded by long cirri, being ventral in position, skewed a little to
the left, and just back of the pointed snout. The anus is near the hinder
end, a little to the left of the median line. The anterior portion of the
digestive tract forms the extensive pharynx, the walls of which are per-
forated by numerous paired gill slits. Through these, respiratory water,
which is taken in at the mouth, streams into a peribranchial chamber,
which communicates with the outside through a median ventral pore in
the hinder half of the body. In the mid-dorsal as well as the mid-
ventral line of the pharynx is a ciliated groove, the latter of which is
homologous to the endostyle of tunicates. Back of pharynx the straight
intestine passes to the anus, the only digestive gland being the liver, a
long diverticulum which extends from the intestine forwards into the
peribranchial chamber. The notochord is a cylindrical rod which forms
the axial skeleton of the body, through which it extends from tip to tip,
lying just above the digestive tube. Above it lies the spinal cord,
which possesses a central canal, the anterior end of which expands to
form a vesicle. Metameric pigment spots, an olfactory pit at the ante-
rior end, and bristle-tipped cells in the skin are the organs of special
sense.

The vascular system consists of a ventral longitudinal blood vessel
which lies beneath the intestine and pharynx, breaking up into capil-
laries (portal system) over the liver, a dorsal vessel over the intestine
which is double over the pharynx, and lateral vessels connecting these
two. The lateral branches in the wall of the pharynx become branchial
vessels; in the hinder portion of the animal the lateral vessels break up
into capillaries on the wall of the intestine. A heart is not present but
the anterior portion of the ventral trunk and others of the larger vessels
are contractile; the blood is colorless. The excretory system consists of
numerous pairs of nephridia which lie above the upper ends of the gill
slits and communicate with the peribranchial chamber. The sexes are
separate, the gonads being a series of glands which lie along the side of
the body opposite the pharynx, projecting into the peribranchial chamber,
into which their products are discharged.

Amphioxus was discovered in 1778 by Pallas, who, believing it to be
a slug, gave it the name Limax lanceolatus. In 1834 Costa gave the
animal the generic name of Branchiostoma. Two years later Yarrell,
not knowing of Costa's work, named it Amphioxus, which has been the

Quart. Jour. Mic. Sci., Vol. 37, p. 303, 1895. "Cephalochordata," Camb. Nat. Hist.,
1904. "Maldive Cephalochordates," etc., by G. H. Parker, Bull. Mus. Comp. Zool.,
Vol. 46, p. 39, 1904,

LEPTOCAEDIA

673

familiar name of the animal ever since. Johannes Miiller (1842) recog-
nized its relation to vertebrates, and Kowalevsky (1867) described its
embryology and elucidated its relationship to tunicates.

The Leptocardia are found in shallow bays in many places in tropical
and temperate regions, and bury themselves in an upright position in the
sand with the mouth projecting into the water. In America they are
found as far north as Chesapeake Bay and in Europe as far as Scandi-
navia. The class contains a single family and about a dozen species.

FAMILY BEANCHIOSTOMIDAE.

With the characteristics of the class: 3 genera.

1. BRANCHIOSTOMA Costa (Amphioxus Yarrell). Body symmetrical;
genital organs on both sides; caudal fin lanceolate: 7 species.

B. lanceolatum

(Pallas) (Fig. 1,016).
Length about 48 mm.;
gonads about 26 pairs:
Chesapeake Bay and
southerly; Europe;
Ceylon. , 6 B ^

B. caribbaeum Sun-
devall. Length 40
mm.; gonads about 26
pairs; differs from B.
lanceolatum in the slight development of the caudal fin and the short-
ness of the postanal region: West Indies, North and South America.

B. calif orniense Cooper. Length 70 mm.; gonads 31 pairs; cephalic
region small : California.

2. ASYMMETRON Andrews. Body
asymmetrical; gonads on right side
only; ventral fin with no fin rays and
poorly developed; a long caudal proc-
ess present : 7 species.

A. lucayanum* And. Length 13

mm.; gonads 29 in number, extending from myotomes 15 to 43 inclu-
sive; olfactory pit wanting: Bahamas; Zanzibar.

A. macricaudatum Parker (Fig. 1,017). Length 14 mm.; number of
gonads about 26, extending from myotomes 11 to 37 inclusive: Florida
coast.

Fig. 1,016 — BrancJiiostoma lancelatum,. A, ventral
aspect; B, left side of body (Cambridge Natural His-
tory). 1, oral cirri; 2, muscle segments; 3, dorsal
fin ; 4, ventral pore of peribranchial chamber ; 5, anus ;
6, gonads ; 7, ventral fin.

Fig. 1,017 — Asymmetron lucayanum —
left side of tail (Parker).

* See "An Undescribed Acraniate," etc., by E. A. Andrews, Stud. Blol. Lab.,
Johns Hop. Univ., Vol. 5, p. 213, 1893.

LIST OF AUTHORS

This list includes the authors of all specific and generic names and also
those of the monographs and treatises herein referred to.

ABBOTT, CHARLES C. (1843 — ). American naturalist and archaeologist resident In

Trenton, N. J.

ABILDGAARD, PETER (1740-1808). Danish physician and naturalist.
ADAMS, ARTHUR. English navy surgeon and conchologist ; middle of last century ;

brother of Henry.

ADAMS, CHARLES B. (1814-1853). American conchologist; professor in Amherst.
ADAMS, HENRY. English conchologist ; middle of last century ; brother of Arthur.
ADANSON, MICHAEL (1727-1806). French conchologist.
AOASSIZ, ALEXANDER (1835-1910). American zoologist resident in Cambridge, Mass. ;

son of Louis.

AGASSIZ, ELIZABETH C. (d. 1907). American naturalist ; wife of Louis.
AGASSIZ, Louis (1807-1873). Swiss-American zoologist; professor in Harvard.
ALBERS, JOHANN (b. 1805). German conchologist and physician.
ALDER, JOSHUA (1792-1867). English zoologist and merchant.
ALLMAN, GEORGB JAMES (1812-1898). Irish zoologist; professor in Dublin and

Edinburgh.

ANDRES, ANGELO. Italian zoologist ; professor in Milan.

ANDREWS, ETHAN A. (1859 — ). American zoologist; professor in Johns Hopkins.
ANTHONY, JOHN G. American conchologist ; middle of last century.
ARCHER, WILLIAM (1830-1897). Irish naturalist and microscopist resident in Dublin.
ARISTOTLE (384 B.C.-322 B.C.). Greek philosopher and naturalist.
ASCANIAS, PETER (1723-1803). Danish zoologist; professor in Copenhagen.
ATKINSON, GEORGE F. (1854 — ). American botanist; professor in Cornell.
AUDUBON, JOHN JAMES (1780-1851). American ornithologist, naturalist and painter

of birds and mammals.

AUDOUIN, JEAN (1797-1841). French zoologist and entomologist; professor in Paris.
AUERBACH, LEOPOLD (b. 1828). German microscopist and protozoologist ; professor in

Breslau.

BAER, KARL ERNST VON (1792-1876). Russian zoologist; professor in Petrograd.

BAILEY, J. W. English microscopist ; middle of last century.

BAIRD, SPENCER F. (1823-1887). American naturalist; secretary of the Smithsonian

Institution.

BAIRD, WILLIAM (1803-1872). English zoologist and physician in London.
BAKER, FRANK C. (1867 — ). American conchologist; Chicago Academy of Sciences.
BANKS, NATHAN (1868 — ). American entomologist and zoologist; U. S. Department

of Agriculture.

BARBAGALLO, PIETRO. Italian parasitologist and physician in Catania.
BARKER, FRANKLIN D. (1877 — ). American zoologist and helminthologist ; professor

in the University of Nebraska.

BARNES, DANIEL W. (d. 1818). American conchologist and preacher.
BARTON, BENJAMIN SMITH (1766-1815). American naturalist resident in

Philadelphia.
BARTRAM, JOHN (1699-1777). American botanist and naturalist resident in

Philadelphia.

BARTRAM, WILLIAM (1739-1823). American botanist and ornithologist; son of John.
BASSI, ROBERTO. Italian veterinary and zoologist ; professor in Turin.
BASTIAN, H. CARLTON (1837 — ). English physician and microscopist; professor in

University College, London.

BATESON, WILLIAM (1861 — ). English zoologist; director of John Innes Horticul-
tural Institution, Merton Park, Surrey.

675

676 LIST OF AUTHORS

BATSCH, AUGUST (1761-1802). German botanist; professor in Jena.

BAVAY, PAUL. Belgian physician ; professor In Brussels.

BEAUVOIS, PALISOT DB (1755-1820). French naturalist who came to America in 1791

and traveled here extensively.

BECK, LEWIS C. (1800-1853). American naturalist and chemist.
BEDDARD, FRANK E. (1858 — ). English zoologist; Zoological Garden, London.
BEECHER, CHARLES E. (1856-1904). American paleontologist; professor in Yale.
BELL, F. JEFFREY. English zoologist ; professor in London.
BELL, THOMAS (1792-1880). English zoologist; professor in London.
BELLEVUE, FLEURIAU. French conchologist ; first part of last century.
BELLINGHAM, O'BRYEN (1805-1877). Irish parasitologist and physician.
BENEDBN, PIERRE JOSEPH VAN (1809-1891). Belgian zoologist; professor in Louvain.
BENEDICT, JAMES E. (1852 — ). American zoologist; U. S. National Museum.
BENHAM, WILLIAM B. (1860 — ). English zoologist; professor in the University of

Otago, New Zealand.

BENSON, W. H. Anglo-Indian conchologist ; first half of last century.
BBRGER, EDWARD W. (1869 — ). American zoologist; state entomologist of Florida.
BERGH, LUDWIG (b. 1824). Danish zoologist.

BERKELEY, M. J. (1803-1889). English clergyman and naturalist.
BERLESB, ANTONIO. Italian zoologist and entomologist ; professor in Florence.
BEST, ROBERT. American naturalist and physician In Cincinnati ; early in the last

century.

BEYER, HENRY G. (1850 — ). German-American physiologist and navy surgeon.
BIGELOW, ROBERT P. (1863 — ). American zoologist; librarian in Massachusetts In-
stitute of Technology.
BILHARZ, THEODOR (1825-1862). German physician and naturalist; professor in the

Medical School in Cairo.

BINNEY, AMOS (1803-1847). American conchologist and physician in Boston.
BINNBY, W. G. (1833-1909). American conchologist; son of Amos.
BIRGB, EDWARD A. (1851 — ). American zoologist; professor in the University of

Wisconsin.

BLACKWBLL, JOHN A. (1790-1881). English arachnologist.
BLAINVILLB, HENRI DB (1778-1850). French zoologist; professor in Paris.
BLANCHARD, EMILB (1820-1900). French zoologist and helminthologist ; professor

In Paris.
BLANCHARD, RAPHAEL (1857 — ). French zoologist and helminthologist; professor in

Paris ; son of Emile.

BLAND, THOMAS. American conchologist ; middle of last century.
BLOCK, MARCUS (1723-1799). German ichthyologist and a physician in Karlsbad.
BLUMBNBACH, JOHANNES (1752-1840). German zoologist and naturalist; professor

in Gottingen.

BOAS, J. E. V. (1855 — ). Danish zoologist; professor in Copenhagen.
BOECK, AXEL. Norwegian zoologist and microscopist ; middle of last century.
BOHADSCH, JOHANN (1724-1768). Bohemian zoologist; professor in Prague.
BOHMIG, LUDWIG (1858 — ). German zoologist; professor in Graz.
BOISDUVAL, JEAN (1801-1879). French physician and entomologist in Paris.
BOLLMAN, CHARLES H. (1868-1889). American zoologist; student in the University

of Indiana and assistant in the Fish Commission. '

BOLTEN, JOHANNES (1718-1796). German naturalist and physician in Hamburg.
BONAPARTB, CHARLES LUCIEN (1803-1857). French ornithologist; nephew of Napo-
leon ; he lived in Philadelphia from 1822 to 1828.
BONNIER, GASTON (1853 — ). French botanist; professor in Paris.
BONZ, CHRISTOPHER GOTTLIEB. German zoologist of the 18th century.
BORING, ALICE M. American zoologist ; professor in the University of Maine.
BORN, IGNAZ VON (1742-1791). Austrian conchologist and mineralogist.
BORY DB SAINT VINCENT, JEAN (1780-1846). French zoologist, botanist and army

officer.
Bosc, Louis (1759-1828). French zoologist and botanist ; he traveled in the United

States in 1796.

BOUVIER, EUGENE Louis. French zoologist and entomologist ; professor in Paris.
BOWDITCH, T. EDWARD. English conchologist ; first half of last century.
BOWERBANK, JOHN S. (1797-1877). English naturalist and merchant.
BRADY, GEORGE S. (1832 — ). English zoologist and physician in Sheffield.

LIST OF AUTHORS 677

BBANDES, GUSTAV (1862 — ). German zoologist; director of the Zoological Garden In

Dresden.

BRANDT, JOHANN FBIEDRICH (1802-1879). Russian zoologist ; professor in Petrograd.
BBAUN, MAX (1850 — ). German zoologist and helminthologist ; professor in

Konigsberg.

BRODEBIP, WILLIAM (1789-1859). English lawyer and naturalist.
BRONN, HEINRICH (1800-1862). German zoologist; professor in Heidelberg.
BROOKS, WILLIAM K. (1848-1908). American zoologist ; professor in Johns Hopkins.
BBOWN, THOMAS. English conchologist ; first half of last century.
BBOWNE, PATBICK (1720-1790). Irish naturalist and physician.
BuuGuifcRE, JEAN (1750-1798). French traveler and zoologist in Montpellier.
BRUNNICH, MARTIN (1737-1827). Danish naturalist; professor in Copenhagen.
BRYANT, ELIZABETH B. American arachnologist ; Boston Society of Natural History.
BUCHHOLZ, REINHARDT (1837-1876). German zoologist; professor in Greifswald.
BURGER, OTTO (1865 — ). German zoologist; professor for 8 years in Santiago, Chile.
BURMEISTER, KARL (1807-1861). German zoologist; professor in Halle and later

Director of the Natural History Museum in Buenos Ayres.
BURNETT, W. J. (d. 1853). American microscopist.

BUSH, KATHARINE J. (1855 — ). American zoologist; Peabody Museum, New Haven.
BUSK, GEORGE (1807-1886). English zoologist and paleontologist.
BUTSCHLI, OTTO (1848 — ). German zoologist; professor in Heidelberg.

CALKINS, GARY N. (1869 — ). American zoologist and protozoologist ; professor in

Columbia.

CALL, R. ELLSWORTH (1856 — ). American zoologist; teacher in New York City.
CAMBRIDGE, O. P. English clergyman and arachnologist ; latter part of last century.
CAMERANO, LORENZO. Italian zoologist ; professor in Turin.
CANESTRINI, GIOVANNI. Italian zoologist; professor in Padua.

CARPENTER, PHILIP P. (1820-1877). English conchologist and clergyman in Mon-
treal ; a brother of W. B. Carpenter.
CARPENTEB, P. HERBERT (d. 1891). English zoologist.
CARPENTER, WILLIAM B. (1813-1885). English physician and naturalist; professor

in London.

CARTER, H. J. English zoologist and microscopist ; middle of last century.
CARUS, JULIUS VICTOR (1823-1903). German zoologist; professor in Leipzig.
CARY, LEWIS R. (1880 — ). American zoologist; professor in Princeton.
CASAGRANDI, ODDO. Italian protozoologist and physician in Catania.
CASTLE, WILLIAM E. (1867 — ). American zoologist; professor in Harvard.
CATESBY, MARK (1680-1759). English naturalist and traveler in America.
CELLI, ANGELO. Italian protozoologist ; professor in Rome.
CERTES, M ME. ADRIEN. French zoologist ; the Muse"e Guimet.
CHAMISSO, ADALBERT (1781-1839). German poet and naturalist of French birth;

custodian of the royal herbarium in Berlin.

CHEMNITZ, JOHANNES (1730-1800). German conchologist and preacher.
CHESTER, WAYLAND M. (1870 — ). American zoologist; professor in Colgate.
CHILD, CHARLES M. (1869 — ). American zoologist; professor in the University of

Chicago.
CHITTBNDBN, FRANK H. (1858 — ). American entomologist; U. S. Department of

Agriculture.

CHUN, CARL (1852-1914). German zoologist; professor in Leipzig.
CIENKOWSKY, LEON (b. 1822). Russian botanist and microscopist; professor in

Charkow.

CLAPAREDE, JEAN (1832-1871). Swiss zoologist; professor in Geneva.
CLARK, AUSTIN H. (1880 — ). American zoologist; U. S. National Museum.
CLARK, H. JAMES (1826-1873). American zoologist; professor in the Massachusetts

Agricultural College in Amherst.
CLARK, HUBERT LYMAN (1870 — ). American zoologist; Museum of Comparative

Zoology, Cambridge, Mass.

CLADS, CARL (1835-1899). German zoologist; professor in Vienna.
CLERCK, CARL (b. 1757). Swedish entomologist and painter.

CLOQUET, JULES (1790-1843). French physician and naturalist; professor in Paris.
COBBOLD, THOMAS SPENCER (1828-1886). English helminthologist and naturalist;

professor in the Royal Veterinary College, London.

678 LIST OF AUTHORS

COCKERELL, T. D. A. (1866 — ). English- American zoologist; professor in University
of Colorado.

COB, WESLEY R. (1869 — ). American zoologist; professor in Yale.

COHN, FERDINAND (1828-1898). German botanist and microscopist ; professor in
Breslau.

COMSTOCK, JOHN HENRY (1849 — ). American entomologist and arachnologist ; pro-
fessor in Cornell.

CONKLIN, EDWIN G. (1863 — ). American zoologist; professor in Princeton.

CONN, HERBERT W. (1859 — ). American zoologist and bacteriologist; professor in
Wesleyan.

CONRAD, TIMOTHY A. (1803-1877). American conchologist and naturalist resident
in Philadelphia.

COOK, MELVILLE T. (1868 — ). American botanist; Delaware Agricultural Experi-
ment Station.

COOKE, A. H. English clergyman and conchologist ; headmaster of Aldenham School,
Herts.

COOPER, J. G. American conchologist ; latter half of the last century.

COPE, EDWARD D. (1840-1897). American zoologist and paleontologist; professor in
the University of Pennsylvania.

COSTA, ACHILLE (d. 1898). Italian zoologist; professor in Naples.

COUES, ELLIOTT (1842-1899). American ornithologist and army surgeon.

COUNCILMAN, WILLIAM T. (1854 — ). Professor of pathology in Harvard.

COUTHOUY, JOSEPH P. (1808-1864). American conchologist; took part in the Wilkes
Expedition.

COWLES, R. P. (1872 — ). American zoologist; university of the Philippines,
Manila.

CRANDALL, O. A. American conchologist resident in Sedalia, Mo.

CRAWLEY, HOWARD (1869 — ). American zoologist and protozoologist ; Department
of Agriculture, Washington.

CRBPLIN, FRIEDRICH. German parasitologist ; first half of last century.

CROSBY, CYRUS R. (1879 — ). American entomologist; professor in Cornell.

CUNNINGHAM, DANIEL J. (1850-1909). Scotch physician and naturalist; professor
in Dublin and Edinburgh.

CURTICE, COOPER K. American parasitologist and veterinary ; Department of Agri-
culture ; latter part of last century.

CURTIS, WINTERTON C. (1875 — ). American zoologist; professor in the University
of Missouri.

CUSHMAN, JOSEPH A. American zoologist ; Boston Society of Natural History. .

CUVIER, GEORGES, BARON DE (1769-1832). French zoologist, paleontologist and com-
parative anatomist ; professor in Paris.

CZBRNIAVSKY, ALEXANDER VON (1850 — ). Russian zoologist.

DA COSTA, EMANUEL. English conchologist ; latter part of the 18th century.

DADAY, EUGENE. Hungarian zoologist ; professor in Budapest.

DALL, WILLIAM H. (1845 — ). American zoologist and conchologist; Smithsonian

Institution, Washington.

DALYELL, JOHN G. (1775-1851). Scotch naturalist and antiquary.
DANA, JAMES DWIGHT (1813-1895). American geologist and zoologist; professor in

Yale.

DANIELSSEN, CORNELIUS. Norwegian zoologist ; director of the Museum in Bergen.
DARWIN, CHARLES (1809-1882). English naturalist and evolutionary philosopher.
DAUDIN, FRANCOIS (1774-1804). French zoologist.
DAVENPORT, CHARLES B. (1866 — ). American zoologist; director of the Station for

Experimental Evolution of the Carnegie Institution of Washington, the Eugenic

Record Office and the Biological Laboratory, all at Cold Spring Harbor, L. I.
DAVIDOPF, MICHAEL. Russian zoologist ; director of the Marine Laboratory in Ville-

franche, France.

DAVIDSON, THOMAS (1817-1885). Scotch paleontologist and zoologist.
DEAN, BASHPORD (1867 — ). American zoologist; professor in Columbia.
DEFRANCE, M. (1758-1850). French zoologist.
DE GEER, KARL (1720-1778). Swedish zoologist.
DEKAY, JAMES E. (1782-1851). American naturalist and physician in Oyster

Bay, L. I.

LIST OF AUTHOES 679

DELAGE, MARIE-YVES (1854 — ). French zoologist; professor In Paris.

DELAROCHE, FRANCOIS (b. 1780). French icthyologlst.

DELLE CHIAJE, STEPANO (d. 1859). Italian zoologist and helminthologist ; professor
in Naples.

DESHAYES, GIRARD (b. 1795). French conchologist ; professor in Paris.

DESOR, EDOUARD (1811-1882). German-Swiss geologist and naturalist; he accom-
panied Agassiz to America in 1846 but returned to Switzerland.

DIESING, KARL (180O-1867). Austrian zoologist and helminthologist resident In
Vienna.

DILLWYN, Louis W. (1778-1855). English naturalist.

DOBIE, M. W. English microscopist ; middle of last century.

DODERLEIN, LUDWIQ (1855 — ). German zoologist; professor in Strassburg.

DODGE, CHARLES W. (1863 — ). American biologist; professor in Rochester
University.

DOFLEIN, FRANZ. German zoologist and protozoologist ; professor in Freiburg.

DONOVAN, EDWARD (d. 1837). English naturalist and painter.

DOYERE, Louis (b. 1811). French naturalist; professor in Versailles.

DRAPARNAUD, JACQUES (1772-1805). French conchologist; professor in Montpellier.

DRASCHE, RICHARD VON. Austrian zoologist resident in Vienna.

DREW, OILMAN A. (1868 — ). American zoologist; assistant director of the Marine
Biological Laboratory, Woods Hole, Mass.

DUBEN, GUSTAV VON. Swedish physician and zoologist ; middle of last century.

DUBINI, ANGELO. Italian parasitologist and physician in Milan ; first half of last
century.

DUERDEN, J. E. English zoologist ; professor in Rhodes University College,
Grahamstown.

DUFOUR LEON (1782-1865). French entomologist and physician in St. Sever.

DUGES, ANTOINE (1798-1838). French zoologist and physician; professor in Mont-
pellier.

DUJARDIN, FELIX (1801-1860). French zoologist; professor in Paris.

DUMERIL, ANDRE (1774-1860). French physician and naturalist; professor in Paris.

DUMORTIER, EARTH. CHARLES (1797-1878). French zoologist and botanist.

DUTTON, J. EVERETT. English parasitologist and physician in the School of Tropical
Medicine, Liverpool.

EDMONDSON, CHARLES H. (1869 — ). American zoologist; professor in Washburn
College.

EDWARDS, CHARLES L. (1863 — ). American zoologist resident in Los Angeles.

EHLERS, ERNST (1835 — ). German zoologist; professor in Gottingen.

EHRENBERG, CHRISTIAN GOTTFRIED (1795-1876). German zoologist; professor in
Berlin.

EISEN, GUSTAV (1847 — ). Swedish-American zoologist resident in San Francisco.

ELLIOTT, STEPHEN (1771-1830). American naturalist; professor in the South Caro-
lina State Medical College, Charleston.

ELLIS, JOHN (1710-1776). English zoologist; a merchant who was interested in
natural science.

EMERTON, JAMES H. (1847 — ). American zoologist and arachnologist resident in
Boston, Mass.

ENTZ, GEZA. Hungarian zoologist ; professor in Budapest.

ERCOLANI, G. B. Italian zoologist and helminthologist.

ERICHSON, WILHELM (1809-1848). German zoologist; professor in Berlin.

ESCHSCHOLTZ, JOHANN FRiEDRiCH (1793-1831). Russian zoologist and physician;
professor in Dorpat.

ESPER, EUGEN (1742-1810). German zoologist; professor in Erlangen.

EYSENHARDT, C. G. "German zoologist and parasitologist ; first half of last century.

FABRICIUS, JOHANN CHRISTIAN (1745-1808). Danish zoologist; professor in Kiel.

FARRE, ARTHUR (1811-1887). English physician and microscopist.

FAXON, WALTER (1848 — ). American zoologist; Museum of Comparative Zoology,

Cambridge, Mass.

FELETTI, RAIMONDO. Italian physician and parasitologist ; professor in Catania.
FERUSSAC, JEAN DB (1786-1836). French conchologist and army officer.

680 LIST OF AUTHORS

FEWKES, J. WALTER (1850 — ). American zoologist and ethnologist; Smithsonian

Institution, Washington.
FISCHER, HEINRICH (1817-1886). German zoologist and mineralogist; professor in

Freiburg.

FISCHER, PAUL (1835-1893). French conchologist and zoologist.
FISCHGDER, FRANZ (1865 — ). German veterinary and parasitologist; in Konigsberg

and Bromberg.

FISHER, WALTER K. (1878 — ) American zoologist; professor in Leland Stanford.
FITZINGER, LEOPOLD (1802-1884). Austrian zoologist resident in Vienna.
FLEMING, JOHN (1785-1857). Scotch zoologist; professor in Edinburgh.
FOCKE, GUSTAV (1810-1877). German naturalist and physician in Bremen.
FOL, HERMAN (1845-1892). Swiss zoologist; professor in Geneva.
FORBES, EDWARD (1815—1854). Scotch zoologist; professor in Edinburgh.
FORBES, STEPHEN A. (1844 — ). American zoologist; professor in the University of

Illinois.

FORSKAL, PETER (1736-1768). Swedish naturalist and traveller.
FRAIPONT, JULIEN. Belgian zoologist and parasitologist ; University of Liege.
FRANTZIUS, ALEXANDER. German microscopist ; middle of last century.
FRASER, C. MCLEAN. American zoologist ; Biological Station, Nanaimo, B. C.,

Canada.

FRfiMiNviLLE, CHRISTOPHB DE (b. 1787). French zoologist and marine officer.
FRESENIUS, GEORG (1806-1866). German microscopist.
FROELICH, JOHANNES (d. 1841). German physician and entomologist.
FROMENTEL, Louis DE (b. 1824). French physician and naturalist.
FUESSLI, JOHANN (1743-1786). Swiss naturalist and entomologist; in Zurich.
FURST, CAMILLO (1852 — ). Austrian physician in Vienna.

GABB, WILLIAM M. (1839-1878). American paleontologist.

GAERTNER, JOSEPH (1732-1791). German naturalist; professor in Tubingen and
Petrograd.

GAIMARD, PAUL (1790-1858). French zoologist; together with Quoy he made voy-
ages to the South Seas in 1817 and 1826.

GALLOWAY, THOMAS W. (1866 — ). American zoologist; professor in Beloit College.

GARDEN, ALEXANDER (1730-1791). American naturalist and physician in Charles-
ton, S. C.

GARMAN, HARRISON (1858 — ). American biologist; state entomologist of Kentucky.

GARRISON, PHILIP E. American parasitologist ; Marine Hospital Service,
Washington.

GEGENBAUR, KARL (1826-1903). German anatomist and zoologist; professor in
Heidelberg.

GEOFFROY-SAINT-HILAIRE, ETIENNE (1772-1844). French zoologist; professor in
Paris ; was in Egypt with Napoleon.

GERLACH, ANDREAS (1811-1877). German veterinary and parasitologist; professor
in Berlin.

GEROULD, JOHN H. (1868 — ). American zoologist; professor in Dartmouth.

GERSTECKER, ADOLF (b. 1828). German zoologist; professor in Greifswald.

GERVAIS, PAUL (1816-1879). French zoologist and paleontologist; professor In
Paris.

GIARD, ALFRED (1846 — ). French zoologist; professor in Paris.

GIBBES, ROBERT W. (1809-1866). American naturalist and physician in Charles-
ton, S. C.

GIESBRECHT, WiLHELM. German zoologist ; professor In the Zoological Station,
Naples.

GILBERT, AUGUSTIN. French physician and professor in Paris.

GILL, THEODORE N. (1837 — ). American zoologist; professor in George Washington
University, Washington, D. C.

GIRARD, CHARLES (1822-1895). French-American zoologist; Smithsonian
Institution.

GMELIN, JOHANN FRIEDRICH (1748-1804). German naturalist; professor In Gottln-
gen ; edited the 13th edition of Linnaeus' Systema Naturae.

GODMAN, JOHN D. (1794-1830). American naturalist and physician in Philadelphia.

GOEZB, JOHANN (1748-1804). German parasitologist and pastor in Quedlinburg.

GOLDFUSS, GEORG (1782-1848). German zoologist; professor in Bonn.

LIST OF AUTHORS 681

GOODB, GEORGE BROWN (1851-1896). American zoologist and Ichthyologist; director
of the U. S. National Museum.

GOSSB, PHILLIP HENRY (1810-1888). English zoologist and naturalist.

GOTO, SEITARO (1867 — ). Japanese zoologist; professor in Tokyo.

GOULD, AUGUSTUS A. (1805-1866). American zoologist and physician in Boston.

GRAFF, LUDWIG VON (1851 — ). Austrian zoologist; professor in Graz.

GRANT, ROBERT E. (1793-1874). English physician and zoologist; professor in
London.

GRASSI, GIOVANNI BATTISTA. Italian zoologist and parasitologist ; professor in Rome.

GRAVE, CASWELL (1870 — ). American zoologist; professor in Johns Hopkins.

GRAY, JOHN EDWARD (1800-1875). English naturalist; keeper of the zoological col-
lections of the British Museum.

GREEF, RICHARD (b. 1829). German zoologist; professor in Marburg.

GRIFFIN, LAWRENCE E. (1874 — ). American zoologist; professor in Philippine Med-
ical School, Manila.

GRIFFITH, EDWARD. English conchologist ; first half of last century.

GRUBE, ADOLF (1812-1880). German zoologist; professor in Breslau.

GRUBER, AUGUST. German protozoologist ; professor in Freiburg.

GRUBY, DAVID (1810-1898). French microscopist ; professor in Paris.

GUERNE, JULES DE. French zoologist resident in Paris.

GUILDING, LANSDOWNE. English zoologist and naturalist ; first half of last century.

GUNNERUS, JOHAN (1718-1773). Norwegian zoologist.

GURLEY, R. R. American physician and protozoologist ; assistant in Fish
Commission.

HAECKEL, ERNST (1834 — ). German zoologist; professor in Jena.

HAGEN, HERMANN (1817-1893). German-American entomologist; professor in
Harvard.

HALDEMAN, SAMUEL S. (1812-1880). American naturalist; professor in the Univer-
sity of Pennsylvania.

HALL, MAURICE C. (1881 — ). American zoologist; Department of Agriculture,
Washington.

HAMANN, OTTO (1857 — ). German zoologist; professor in Berlin.

HANCOCK, ALBANY (1806-1S73). English zoologist and manufacturer.

HANLEY, SYLVANUS. English conchologist ; middle of last century.

HANSEN, HANS J. Danish entomologist resident in Copenhagen.

HARGER, OSCAR (1843-1887). American zoologist; assistant in the Tale Museum.

HARGITT, CHARLES W. (1852 — ). American zoologist; professor in Syracuse
University.

HARGITT, GEORGE T. (1881 — -). American zoologist; professor in Syracuse
University ; son of Charles W.

HARLAN, RICHARD (1796-1843). American naturalist and physician in Philadelphia.

HARRING, HARRY K. American zoologist ; U. S. Bureau of Standards, Washington.

HARRIS, J. ARTHUR (1880 — ). American botanist and zoologist; Station for Experi-
mental Evolution, Cold Spring Harbor, N. Y.

HARRIS, THADDEUS W. (1795-1856). American entomologist and physician in Boston.

HARTMAN, WILLIAM D. (1817-1899). American conchologist and physician in West
Chester, Pa.

HARTMEYER, ROBERT. German zoologist ; Zoological Museum, Berlin.

HARVEY, F. L. (d. 1900). American naturalist ; professor in the University of Maine.

HASSALL, ALBERT (1862 — ). American parasitologist; Bureau of Animal Industry,
Washington.

HATSCHEK, BERTHOLD (1854 — ). Austrian zoologist; professor in Vienna.

HAY, WILLIAM P. (1872 — ). American zoologist; professor in Washington, D. C.

HEIDER, KARL (1856 — ). Austrian zoologist; professor in Innsbruck.

HELLER, ARNOLD (1840 — ). German anatomist and parasitologist; professor in Kiel.

HEMPEL, A. American microscopist.

HENLE, FRIEDRICH (1809-1885). German physician and naturalist; professor in
Gottingen.

HENRY, JOSEPH (1797-1878). American physicist; first secretary of the Smithso-
nian Institution.

HENTZ, NICHOLAS M. (1797-1856). German-American naturalist and educator.

HERDMAN, WILLIAM A. (1858 — ). Scotch zoologist; professor in Liverpool.

682 LIST OF AUTHOES

BERING, EDODARD (b. 1834). German zoologist; professor in Prague.
HERMANN, JEAN (1738-1800). French physician and naturalist; professor in

Strassburg.

HfiROUARD EDGARD. French zoologist ; professor in Paris.
HERRICK, CLARENCE L. (1858-1904). American zoologist and naturalist; president

of the University of New Mexico.
HERRICK, FRANCIS H. (1858 — ). American zoologist; professor in Western Reserve

University.

HERTWIG, RICHARD (1850 — ). German zoologist; professor in Munich.
HESSE, C. E. Belgian helminthologist ; middle of last century.
HEYDEN, LUCAS VON. German zoologist and entomologist ; professor in Frankfort.
HINCKS, THOMAS (1818-1899). English zoologist and clergyman in Leeds.
HINDS, RICHARD B. English navy surgeon and naturalist.
HOLMES, SAMUEL J. (1868 — ). American zoologist; professor in the University of

California.

HUBRECHT, A. A. W. (1853-1914). Dutch zoologist; professor in Utrecht.
HUDSON, CHARLES T. (1828-1903). English naturalist and teacher in Clifton.
HUMBERT, ALOIS. Swiss naturalist ; middle of last century.
HUMBOLDT, ALEXANDER VON (1769-1859). German traveller and naturalist.
HUMPHREY, GEORGE. English conchologist ; latter part of eighteenth century.
HUXLEY, THOMAS HENRY (1825-1895). English zoologist and naturalist; professor

in London.
HYATT, ALPHEUS (1838-1902). American zoologist and paleontologist; Boston

Society of Natural History.
IHERING, HERMANN VON (1850 — ). German-Brazilian zoologist; director of the

Museum, Sao Paulo.

ILLIGER, JOHANNES (1775-1815). German zoologist; director of the Zoological Gar-
den in Berlin.

JACKSON, ROBERT T. (1861 — ). American paleontologist; professor in Harvard.

JAGER, H. German physician ; professor in Kb'nigsberg.

JAGERSKIOLD, LEONARD VON. Swedish zoologist and parasitologist ; the Zoological

Museum, Gothenburg.

JANET, CHARLES. French zoologist and engineer in Beauvais.
JEFFREYS, JOHN G. (1809-1885). English conchologist.

JENNINGS, HERBERT S. (1868 — ). American zoologist; professor in Johns Hopkins.
JOHANSSON, LUDWIG. Swedish zoologist ; in the University of Gothenburg.
JOHNSON, HERBERT P. (1864 — ). American zoologist and protozoologist ; professor

in St. Louis.

JOHNSON, JAMES R. Scotch physician in Edinburgh.
JOHNSTON, GEORGE (1797-1855). Scotch naturalist and physician in Berwick on

Tweed.
JORDAN, DAVID STARR (1851 — ). American ichthyologist and naturalist; Chancellor

of Leland Stanford.

JUDAY, CHANCEY. American zoologist ; lecturer in the University of Wisconsin.
JURINE, Louis (1751-1819). Swiss physician and zoologist; professor in Geneva.

KALM, PETER (1715-1790). Swedish naturalist and pupil of Linnaeus; travelled in

America.
KEEP, JOSIAH (1849-1913). American conchologist; professor in Mills College,

California.

KEFERSTEIN, W. (1833-1870). German zoologist; professor in Gb'ttingen.
KELLICOTT, DAVID S. (1842-1898). American microscopist and zoologist; professor

in Ohio State University.

KELLOGG, JAMES L. (1866 — ). American zoologist; professor in Williams.
KELLOGG, VERNON L. (1867 — ). American entomologist and zoologist; professor in

Leland Stanford.
KENT, W. SAVILLE. English protozoologist and ichthyologist ; formerly in the British

Museum.

KERBERT, C. Dutch zoologist and parasitologist resident in Amsterdam.
KESSLER, KARL (d. 1884). Russian zoologist; professor in Petrograd.
KEYSERLING, ALEXANDER VON (1815-1891). Russian naturalist and traveller.

LIST OF AUTHORS

KILBOURNE, EDWIN D. American army surgeon.

KING, WILLIAM (1809-1886). English geologist and naturalist; professor in Queens

College, Galloway.

KINGSLEY, JOHN STERLING (1854 — ). American zoologist; professor in the Univer-
sity of Illinois.

KLEBS, GEORG. German botanist and microscopist ; professor in Heidelberg.
KLEIN, JAKOB THEODOR (1685-1759). German zoologist; an opponent of Linnaeus.
KOCH, CARL LUDWIG (1806-1888). German zoologist and arachnologist.
KOFOID, CHARLES A. (1865 — ). American zoologist; professor in the University of

California.
KOLLIKER, ALBERT VON (1817-1905). German anatomist and zoologist; professor

in Wurzburg.

KONIKE, FERDINAND. German zoologist resident in Bremen.
KOREN, J. Norwegian zoologist ; custos in the Museum in Bergen.
KORSCHELT, EUGEN (1858 — ). German zoologist; professor in Marburg.
KOWALEVSKY, ALEXANDER (1840-1901). Russian zoologist; professor in Petrograd.
KRAEPELIN, KARL. German zoologist; director of the National History Museum,

Hamburg.

KROHN, AUGUST. German zoologist ; first half of last century.
KROYER, HENRIK (b. 1799). Danish naturalist resident in Copenhagen.
KUCHENMEISTER, GoTTLOB (1821-1890). German parasitologist and physician In

Zittau.
KURTZ, JOHN D. American conchologist and marine officer ; middle of the last

century.

LABBfi, ALPHONSE. French protozoologist ; School of Medicine in Nantes.
LACAZE-DUTHIERS, HENRI DE (1821-1901). French zoologist; professor in Paris.
LACHMANN, JOHANNES (1832-1860). German zoologist.

LAMARCK, JEAN, CHEVALIER DB (1744-1829). French zoologist, botanist, and evolu-
tionary philosopher.
LAMBE, LAWRENCE M. (1863 — ). Canadian zoologist and paleontologist; Geological

Survey of Canada.

LAMOUROUX, JEAN (1779-1825). French zoologist; professor in Paris.
LANDACRE, FRANCIS L. (1867 — ). American zoologist; professor in Ohio State

University.

LANDOIS, HERMANN (b. 1835). German zoologist; professor In Munster.
LANG, ARNOLD (1855-1914). Swiss zoologist; professor in Zurich.
LANKESTER, E. RAY (1847 — ). English zoologist; director of the department of

Natural History in the British Museum until 1907.
LATREILLE, PIERRE (1762-1833). French zoologist and entomologist; professor in

Paris.

LAVERAN, ALPHONSE (1845 — ). French physician and microscopist; Pasteur Insti-
tute, Paris.

LEA, ISAAC (1792-1886). American conchologist and publisher in Philadelphia.
LEACH, WILLIAM E. (1790-1836). English zoologist; a curator in the British

Museum.

LECLERC, M. French microscopist ; first part of last century.
LE CONTE, JOHN EATON (1784-1860). American naturalist and army engineer; a

brother of Lewis.
LE CONTE, JOHN LAWRENCE (1825-1883). American entomologist and a physician in

Philadelphia ; a son of John E.
LE CONTE, JOSEPH (1823-1901). American geologist; professor in the University of

California ; a son of Lewis.
LE CONTE, LEWIS (1782-1838). American naturalist and physician; a brother of

John E.

LEDERMULLER, MARTIN (1719-1769). German physician and naturalist.
LEEUWENHOEK, ANTON (1632-1723). Dutch naturalist; one of the first to use the

microscope to study animals.
LEPEVRE, GEORGE (1869 — ). American zoologist; professor in the University of

Missouri.

LEGER, Louis. French protozoologist ; professor in Grenoble.
LEHMAN N, RUDOLF. German conchologist and physician in Stettin ; latter part of

last century.

684 LIST OF AUTHORS

LEIDY, JOSEPH (1823-1891). American anatomist, zoologist, and paleontologist ; pro-
fessor in the University of Pennsylvania.
LENDENFELD, ROBERT VON (1858-1913). Austrian zoologist and naturalist; professor

in Prague.

LESKE, NATHANAEL (1751-1786). German zoologist; professor in Marburg.
LESSER, FRIEDRICH (1692-1754). German naturalist and theologian.
LESSON, RfiNfi (1794-1849). French naturalist and traveller; professor in Rochfort.
LESUEDR, CHARLES ALEXANDER (1778-1857). French zoologist ; lived in Philadelphia

from 1817 to 1825.
LEUCKART, FRIEDRICH SIGISMUND (1794-1843). German zoologist; professor in

Freiburg.
LEDCKART, RUDOLF (1822-1898). German zoologist and helminthologist ; professor

in Leipzig ; nephew of Friedrich.

LEUNIS, JOHANNES (1802-1873). German naturalist; professor in Hildesheim.
LEVINSEN, MARIUS. Danish zoologist ; docent in Copenhagen.
LEYDIG, FRANZ (b. 1821). German zoologist; professor in Bonn.
LICHTENSTEIN, MARTIN (1780-1857). German zoologist; professor in Berlin.
LIEVIN, SAMUEL. Russian-German naturalist and physician in Dantzig.
LILLJEBORG, WILHELM. Swedish zoologist ; professor in Upsala ; latter half of last

century.
LINCK, JOHANNES (1674-1734). German zoologist and physician; professor in

Leipzig.

LINDEMANN, KARL. Russian zoologist in Moscow ; in middle of last century.
LINNAEUS, CAROLUS (1707-1778). Swedish naturalist; professor in Upsala.
LINSTOW, OTTO VON (1842 — ). German helminthologist and physician in Gottingen.
LINTON, EDWIN (1855 — ). American parasitologist; professor in Washington and

Jefferson College.

LISTER, MARTIN (1638-1712). English physician and naturalist.
LJUNGMAN, AXEL. Swedish zoologist resident in Lilldal.
Looss, ARTHUR (1861 — ). German zoologist and helminthologist; professor in the

Medical School, Cairo, and in Leipzig.

LOscH, F. Russian physician in Petrograd ; latter part of last century.
LovfiN, SVEN (1809-1895). Swedish zoologist; professor in Stockholm.
LUCAS, HIPPOLYTE (1815-1885). French entomologist and arachnologist.
LUBBOCK, JOHN, LORD AVEBURY (1834-1913). English naturalist and banker in

London.

LUDWIG, HUBERT (1852-1914). German zoologist; professor in Bonn.
LUHE, MAX (1870 — ). German zoologist; professor in Konigsberg.
LUTKEN, CHRISTIAN. Danish zoologist ; professor in Copenhagen.
LYMAN, RUFUS A. American physiologist ; professor in the University of Nebraska.
LYMAN, THEODORE (1833-1897). American zoologist; Museum of Comparative

Zoology, Cambridge, Mass.

MACBRIDE, ERNEST "W. (1866 — ). English zoologist; professor in London.
MACCALLUM, WILLIAM G. (1874 — ). American pathologist and helminthologist; pro-
fessor in Columbia.
MCCLENDON, JESSE F. (1880 — ). American zoologist; professor in the University of

Minnesota.

McCooK, HENRY C. (1837-1911). American zoologist and preacher in Philadelphia.
McCRADY, JAMES (1831-1881). American zoologist; professor in the College of

Charleston, S. C.
MCMURRICH, J. PLAYFAIR (1859 — ). American anatomist and zoologist; professor

in Toronto.

MCNEILL, J. A. American naturalist and collector in Binghamton, N. Y.
MAGALHAES, PEDRO DE. Brazilian zoologist and helminthologist ; professor in Rio

Janeiro.

MALMGREN, A. J. (b. 1834). Finnish zoologist; professor in Helsingfors.
MANSON, SIR PATRICK (1844 — ). English physician and parasitologist; London

School of Tropical Medicine.

MARCHIAFAVA, ETTORE. Italian physician ; professor of pathology in Rome.
MARK, EDWARD L. (1849 — ). American zoologist; professor in Harvard.
MARSH, C. DWIGHT (1855 — ). American zoologist and botanist; Department of

Agriculture, Washington.

LIST OF AUTHORS 685

MARSHALL, RUTH (1869 — ). American zoologist; head of Department of Biology,

Rockford, Wis.
MARSHALL, WILLIAM S. (1866 — ). American zoologist; professor in the University

of Wisconsin.

MARTYN, THOMAS. English conchologist and naturalist ; last half of 18th century.
MARX, GEORGE. German-American arachnologist ; U. S. National Museum.
MAST, SAMUEL O. (1871 — ). American zoologist; professor in Johns Hopkins.
MAUPAS, E. French protozoologist resident in Algiers.
MAYER, ALFRED G. (1868 — ). American zoologist; director of the Department of

Marine Biology of the Carnegie Institution of Washington.
MEAD, ALBERT D. (1869 — ). American zoologist; professor in Brown.
MEINERT, F. Danish entomologist ; the Zoological Museum in Copenhagen.
MENGE, A. (1808-1880). German arachnologist and zoologist.
MENKE, CARL THEODOR (1791-1861). German conchologist.

MENSCH, P. CALVIN (1864-1901). American zoologist; professor in Ursinus College.
MERESHKOWSKI, C. VON. Russian microscopist ; latter half of last century.
MERTENS, CHARLES DE (1737-1788). Belgian physician and naturalist.
METCALF, MAYNARD M. (1868 — ). American zoologist resident in Oberlin, Ohio.
METSCHNIKOFF, ELIAS (1845 — ). Russian zoologist and bacteriologist; the Pasteur

Institute, Paris.

MEYER, CHRISTIAN VON (1801-1869). German paleontologist.
MICHAEL, ALBERT D. (1836 — ). English arachnologist and microscopist ; solicitor in

London.
MICHAEL, ELLIS L. (1881 — ). American zoologist; the Marine Biological Station,

San Diego.
MICHAELSON, WILHELM. German zoologist ; the Natural History Museum in

Hamburg.

MIDDENDOUFF, ALEXANDER VON (b. 1815). Russian zoologist.
MIERS, EDWARD J. English zoologist ; the British Museum.
MIGHELS, J. W. American conchologist and physician.
MILLER, J. S. English zoologist ; in first half of last century.
MILNE-EDWARDS, HENRI (1800-1885). French zoologist ; professor in Paris.
MINCHIN, E. A. (1866-1915). English zoologist; professor in London.
MITZMAIN, MAURICE B. (1882 — ). American entomologist and parasitologist; Bureau

of Science, Manila.

MITCHELL, JOHN (d. 1768). American botanist and naturalist; he lived in Virginia.
MOBIUS, KARL (1825-1909). German zoologist; professor in Kial.
M'ORCH, OTTO (1828-1878). Danish conchologist; the Museum in Copenhagen.
MOLL, H. P. (1S10-1845). Danish zoologist.
MONTAGU, GEORGE (1751-1815). English conchologist and naturalist; ceptain in the

English army during the American Revolution.
MONTFORT, DENIS DE (d. 1820). French conchologist.
MONTGOMERY, THOMAS H. (1873-1912). American zoologist; professor in University

of Pennsylvania.
MONTICELLI, FRANCESCO S. Italian zoologist and helminthologist ; professor in

Naples.
MOORE, ANNE (1872 — ). American biologist; teacher in Normal School, San Diego,

California.
MOORE, HENRY F. (1867 — ). American zoologist; the U. S. Bureau of Fisheries;

brother of J. Percy.
MOORE, J. PERCY (1869 — ). American zoologist; professor in the University of

Pennsylvania.

MORGAN, THOMAS H. (1866 — ). American zoologist; professor in Columbia.
MORSE, EDWARD S. (1838 — ). American zoologist and archaeologist; director of the

Peabody Academy of Sciences at Salem, Mass.
MOSELEY, HENRY N. (1844-1891). English zoologist; on the Challenger Expedition;

a professor in Oxford.

MUHLFELDT, MEGERLB VON. Austrian conchologist ; first half of last century.
MULLER, FRITZ (1821-1897). German zoologist and teacher who in 1852 migrated to

Brazil.
MULLER, JOHANNES (1801-1858). German anatomist, physiologist and naturalist;

professor in Berlin.
MULLER, OTTO FRIEDRICH (1730-1784). Danish zoologist.

686 LIST OF AUTHORS

NALBPA, ALFRED. Austrian microscopist ; gymnasium professor in Vienna.

NARDO, GIOVANNI (1802-1877). Italian parasitologist.

NELSON, JAMES A. (1875 — ). American zoologist; Department of Agriculture,

Washington.

NEWPORT, GEORGE (1803-1854). English entomologist and zoologist.
NICKERSON, WINFIBLD S. (1864 — ). American zoologist and physician in Davenport,

North Dakota.

NICOLET, HERCULE. French entomologist ; the middle of the last century.
NITZSCH, CHRISTIAN LUDWIO (1782-1837). German zoologist; professor in Halle.
NITZSCHE, HEINRICH (1845 — ). German zoologist; professor in the Royal Saxon

Forest Academy in Tharand.

NORDM ANN, ALEXANDER VON (1803-1866). Finnish zoologist ; professor in Helsingfors.
NORDQUIST, OSCAR. Finnish zoologist.

NORMAN, ALFRED M. (1831 — ). English zoologist and clergyman.
NUTTALL, GEORGE H. F. (1862 — ). English physician and parasitologist; professor

in Cambridge, England.
NUTTING, CHARLES C. (1858 — ). American zoologist; professor in Iowa State

University.

ODHNER, TEODOR. Swedish zoologist ; decent in TJpsala.

ODIER, Louis (1748-1817). Swiss physician; professor in Geneva.

OERSTED, ANDREAS (1816-1873). Danish botanist and naturalist; professor in
Copenhagen.

OKEN, LORENZ (1779-1851). German zoologist and natural philosopher; professor
in Zurich.

OLFERS, IGNATZ FR. VON. German conchologist and naturalist resident in Berlin ;
first half of last century.

D'ORBIGNT, ALCIDE (1802-1857). French paleontologist and zoologist, and traveler
in South America.

ORTMANN, ARNOLD (1863 — ). German-American zoologist; professor in Pittsburg.

OSBORN, HENRY L. (1857 — ). American zoologist; professor in Hamline University.

OSBORN, HERBERT (1856 — ). American entomologist; professor in Ohio State
University.

OSBURN, RAYMOND C. (1872 — ). American zoologist; professor in Connecticut Col-
lege for Women, New London, Conn.

OUDEMANS, A. C. Dutch zoologist ; director of the Zoological Gardens in the Hague.

OWEN, RICHARD (1803-1892). English comparative anatomist and paleontologist.

PACKARD, ALPHBUS S. (1839-1905). American zoologist and entomologist; professor

in Brown.

PAGENSTECKER, HEINRICH (b. 1825). German zoologist; professor in Heidelberg.
PALLAS, PETER (1741—1811). German zoologist and naturalist who lived long in

Russia.
PALMER, T. CHALKLEY (1860 — ). American naturalist and manufacturer in

Philadelphia.
PARROTT, PERCIVAL J. (1874 — ). American entomologist; New York Experiment

Station.

PARTSCH, PAUL (1791-1856). German conchologist.

PATTEN, WILLIAM (1861 — ). American zoologist; professor in Dartmouth.
PATTON, W. SCOTT. English protozoologist and physician in the King Institute of

Preventative Medicine, India.
PAULMEIER, FREDERIC P. (1873-1906). American zoologist; State Museum, Albany,

New York.
PBALE, CHARLES WILSON (1741-1827). American portrait painter resident In

Philadelphia.
PEALE, REMBRANDT (1778-1860). American portrait painter and naturalist resident

in Philadelphia and Baltimore ; son of Charles Wilson Peale.
PEARL, RAYMOND (1867 — ). American zoologist; Maine Agricultural Experiment

Station.
PEARSE, ARTHUR S. (1877 — ). American zoologist; instructor in the University of

Michigan.
PECKHAM, ELIZABETH G. (1854 — ). American entomologist and arachnologist ; wife

of George W.

LIST OF AUTHORS 687

PBCKHAM, GEORGE W. (1845-1914). American entomologist and arachnologist ;

teacher and librarian in Milwaukee.

PELSENEER, PAUL. Belgian zoologist ; professor in Ghent.
PERKINS, HENRY F. (1877 — ). American zoologist; professor in the University of

Vermont.
PfiRON, FRANCOIS (1775-1810). French naturalist and soldier; went with Lesueur

on his South Sea voyage in 1800-1804.

PERRIER, EDMOND (1844 — ). French zoologist; professor in Paris.
PERRY, GEORGE. English conchologist ; first part of last century.
PERTY, MAXMILIAN (1804-1884). German naturalist; professor in Berne.
PETERS, WILHELM (1815-1883). German traveler and zoologist; professor in Berlin.
PEYSSONNEL, ANTOINE (b. 1694). French naturalist and physician in Marseilles.
PPEIFPER, LUDWIG (1842 — ). German conchologist and physician in Cassel.
PHILIPPI, RUDOLF (b. 1808). German zoologist and naturalist; traveler in South

America.

PHIPPS, CONSTANTINE JOHN (1746-1892). English naval officer.
PIERSIG, RICHARD. German zoologist ; teacher in Annenberg.
PILSBRY, HENRY A. (1862 — ). American conchologist; Academy of Natural Sciences,

Philadelphia.

PLATE, LUDWIG (1862 — ). German zoologist; professor in Jena.
PLINY MAJOR, CAIUS (23-79). Roman writer on Natural History; killed at the

eruption of Vesuvius which destroyed Pompeii.
PLUMMER, GEORGE A. American navy surgeon.

POCOCK, REGINALD I. (1863 — ). English zoologist; the Zoological Gardens, London.
POIRIER, J. French parasitologist ; professor in Clermont-Ferrand.
POLI, GUISEPPB (1746-1825). Italian naturalist resident in Naples.
POTTS, EDWARD (1830-1912). American zoologist and microscopist resident In

Media, Pa.

POUCHET, FfiLix (1800-1872). French naturalist and physician in Rouen.
PouRTALfcs, Louis DE (1823-1880). French-American zoologist who accompanied

Agassiz to America ; Director of the Museum of Comparative Zoology of Harvard

College.
POWERS, JOSEPH H. (1866 — ). American zoologist; professor in the University of

Nebraska.

PRATT, HENRY S. (1859 — ). American zoologist; professor in Haverford College.
PR£VOST, ISAAC (1755-1819). Swiss naturalist; professor in Montauban.
PRICE, MARSHALL L. (1878 — ). American physician in Baltimore.
PRIME, TEMPLE. American conchologist resident in New York City.
PURKINJB, JOHANN (1787-1869). Bohemian physiologist; professor in Prague.
PUTNAM, J. DUNCAN (1855-1881). American zoologist resident in Davenport, Iowa.

QUATREFAGES, JEAN OB (1810-1892). French zoologist; professor in Paris.
QUBNNERSTEDT, A. Swedish zoologist and protozoologist ; middle of the last century.
QUOY, JEAN (1790-1869). French zoologist ; together with Gaimard he made voyages
to the South Sea in 1817 and 1826.

RACKETT, THOMAS (1757-1841). English naturalist and clergyman.

RAFINESQUE, CONSTANTINB (1784-1842). French-American naturalist and traveler

resident in Lexington, Ky., and Philadelphia.

RAILLET, ALCIDB (1852 — ). French zoologist and physician; professor in Alfort.
RANG, ALEXANDER. French marine officer and zoologist.
RANSOM, BRAYTON H. (1879 — ). American parasitologist; chief of the zoological

division of the Bureau of Animal Industry, Washington.
RATHBUN, MARY J. (1860 — ). American zoologist; U. S. National Museum.
RATHBUN, RICHARD (1852 — ). American zoologist; Smithsonian Institution.
RATHKB, MARTIN (1793-1860). German zoologist; professor in Konigsberg.
RAY, JOHN (1628-1705). English naturalist and clergyman.

REESE, DAVID M. (1800-1861). American naturalist and physician in New York.
REEVE, LOVELL A. (1814-1865). English conchologist and merchant.
RENIER, STEFANO (1759-1830). Italian zoologist.
RETZIUS, ANDREAS JOANNES (1742-1821). Swedish naturalist and helminthologlst ;

professor in Lund.
RICHARDSON, HARRIET. American zoologist ; Smithsonian Institution.

688 LIST OF AUTHOES

RIEHM, JOHANN (1739-1807). German agriculturist and naturalist.

RILEY, CHARLES V. (1843-1895). American economic entomologist; U. S. National

Museum, Washington.

RISSER, JONATHAN (1869 — ). American zoologist; professor in Washburn College.
Risso, J. A. (1777-1845). Italian naturalist; professor in Nice.
RITTER, WILLIAM E. (1856 — ). American zoologist; professor in the University of

California.

RITTER-ZAHONY, RUDOLF VON. German zoologist resident in Berlin.
RIVOLTA, SEBASTIANO (1832-1893). Italian parasitologist.
ROBERTSON, ALICE. American zoologist ; professor in Wellesley.
ROBIN, CHARLES PHILLIPE (1821-1885). French zoologist and anatomist; professor

in Paris.

ROEDERER, JOHANN (1726-1763). German physician; professor in Gottingen.
ROGERS, CHARLES G. (1875 — ). American zoologist and physiologist; professor in

Syracuse University.

RONDELET, GUILLAUME (1507-1556). French naturalist and physician.
ROUSSELET, CHARLES F. English microscopist and zoologist resident in London.
Roux, JEAN. French naturalist and physician in Marseilles.
RUCKER, AUGUSTA (1873 — ). American zoologist; instructor in the University of

Texas.

RUDOLPHI, CARL ASMUND (1771-1832). Swedish zoologist and helminthologist ; pro-
fessor in Berlin.

RUPPELL, WILHELM (1794-1884). German zoologist and African explorer.
RYDER, JOHN A. (1852-1895). American zoologist; professor in the University of

Pennsylvania.

SAGER, ABRAM (1811-1877). American zoologist resident In Ann Arbor, Mich.
SARS, GEORG O. (1837 — ). Norwegian zoologist; professor in Christiania ; son of

Michael.

SARS, MICHAEL (1805-1869). Norwegian zoologist; professor in Christiania.
SAUSSURE, NICHOLAS DE (1767-1845). Swiss naturalist and chemist.
SAVIGNY, M. J. C. DE (1778-1851). French zoologist; went with Napoleon to

Egypt.
SAY, THOMAS (1787-1834). American zoologist; the Academy of Natural Sciences

of Philadelphia.

SCAPOLI, JOHANN (1725-1788). Austrian naturalist; professor in Pavia.
SCHACHT, F. W. American zoologist ; teacher in Chicago High School.
SCHAEPFER, ASA A. American zoologist ; professor in the University of Tennessee.
SCHAEFFER, JACOB (1718-1790). German zoologist and botanist.
SCHAUDINN, FRITZ (1871-1906). German zoologist and protozoologist ; decent in

Berlin.

SCHICK, MORRIS. American conchologist resident in Philadelphia.
SCHLUMBERGER, CHARLES (1859 — ). French paleontologist.

SCHMEIL, OTTO (1860 — ). German zoologist and botanist resident in Heidelberg.
SCHMIDT, OSCAR (1823-1886). German zoologist; professor in Strassburg.
SCHNEIDER, AiMfi. French zoologist and protozoologist ; professor in Poitiers.
SCHNEIDER, ANTON (b. 1831). German zoologist; professor in Breslau.
SCHRANK, FRANZ VON (1747-1835). German botanist and zoologist; director of the

Botanical Garden in Munich.

SCHULTZE, MAX (1825—1874). German anatomist and naturalist; professor in Bonn.
SCHULTZB, SIGISMUND (1798-1874). German anatomist and naturalist; professor

in Greifswald.

SCHULZE, FRANZ EILHARD (1840 — ). German zoologist; professor in Berlin.
SCHUMACHER, CHRISTIAN (1757-1830). Danish naturalist ; professor in Copenhagen.
SCHWEIGGER, AUGUST (1783-1821). German botanist; professor in Konigsberg.
SCUDDER, SAMUEL H. (1837-1911). American entomologist resident in Cambridge,

Massachusetts.

SEDGWICK, ADAM (1854-1913). English zoologist; professor in Cambridge.
SEDGWICK, WILLIAM T. (1855 — ). American biologist; professor in the Massachu-
setts Institute of Technology.

SBLENKA, EMIL (1842 — ). German zoologist; professor in Erlangen.
SEMPER, CARL (1832-1893). German zoologist and traveler; professor in Wiirzburg.
SHAFFER, ELMER (1892—). American zoologist ; student in Haverford and Princeton.

LIST OF AUTHORS 689

SHANTZ, HOMER L. American zoologist and ( botanist ; Department of Agriculture,

Washington.
SHARP, BENJAMIN (1858-1914). American zoologist and traveler resident in

Philadelphia.
SHARPE, RICHARD W. (1869 — ). American zoologist ; teacher in DeWitt Clinton High

School, N. Y.

SHAW, GEORGE (1751-1813). English zoologist and physician in London.
SHAW, WALTER R. (1871 — ). American botanist and entomologist; professor in the

University of the Philippines.

SHIPLEY, ARTHUR E. (1861 — ). English zoologist; lecturer in Cambridge.
SHDLL, A. FRANKLIN. American zoologist; professor in the University of Michigan.
SHUTTLEWORTH, ROBERT J. (1810-1874). English botanist and conchologist.
SIEBOLD, CARL THEODOR ERNST VON (1804-1885). German zoologist; professor in

Munich.

SILLIMAN, BENJAMIN (1779-1864). American scientist ; professor in Yale.
SILLIMAN, WYLLIS A. American zoologist resident in Clarkson, N. Y.
SIMON, EUGENE (1848 — ). French arachnologist resident in Paris.
SIMPSON, CHARLES T. (1846 — ). American conchologist; U. S. National Museum.
SIMROTH, HEINRICH (1851 — ). German zoologist; professor in Leipzig.
SLABBER, MARTIN (1741-1835). Dutch naturalist.
SLADEN, W. PERCY. English zoologist.
SMALL WOOD, WILLIAM M. (1873 — ). American zoologist; professor in Syracuse

University.

SMITH, CLAUDE A. American physician in Atlanta, Georgia.
SMITH, FRANK (1857 — ). American zoologist; professor in the University of

Illinois.

SMITH, HUGH M. (1865 — ). American ichthyologist ; U. S. Commissioner of Fisheries.
SMITH, SIDNEY I. (1843 — ). American zoologist; professor in Yale.
SMITH, THEOBALD (1859 — ). American protozoologist and bacteriologist;

Rockefeller Institute.
SOLANDER, DANIEL (1736-1782). Swedish-English zoologist and botanist; a keeper

of the British Museum.

SOWERBY, GEORGE B. (1788-1834). English zoologist and conchologist.
SOWEREY, GEORGE B. (1812-1884). English zoologist and conchologist ; son of above.
SPENGEL, JOHANN WILHELM (1852 — ). German zoologist; professor in Giessen.
SPENGLER, LORENZ (b. 1720). German conchologist.
STAFFORD, JOSEPH (1867 — ). Canadian zoologist and parasitologist; lecturer in

McGill University.

STARCOVICI, C. Italian veterinary and parasitologist.
STEBBING, THOMAS R. (1835 — ). English zoologist and clergyman in Tunbridge

Wells.
STEEL, JOHN HENRY (d. 1891). English parasitologist and veterinary in Bombay

Veterinary College.
STEENSTRUP,- JOHANN JAPHETUS (1813-1897). Danish zoologist ; professor in

Copenhagen.

STEIN, FRIEDRICH (1818-1885). German zoologist; professor in Prague.
STERKI, VICTOR (1846 — ). Swiss-American zoologist and physician in New Phila-
delphia, Ohio.
STEVENS, NETTIE M. (1861-1913). American zoologist and cytologist ; associate in

Bryn Mawr.
STILES, CHARLES W. (1867 — ). American zoologist and parasitologist; head zoologist

of the Hygienic Laboratory of the U. S. Marine Hospital Service.
STIMPSON, WILLIAM (1832-1872). American zoologist; curator of the Academy of

Sciences in Chicago.

STOKES, ALFRED C. American microscopist and physician in Trenton, N. J.
STOLC, ANT. Bohemian zoologist ; in the Technical High School in Prague.
STONE, GEORGE E. (1860 — ). American botanist; professor in Massachusetts Agrir

cultural College, Amherst.

STORER, DAVID H. (b. 1804). American physician and naturalist in Boston.
STRAUS-DURKHEIM, HERCULES (1790-1865). French zoologist and comparative

anatomist.

STR^M, HANS. Norwegian naturalist and physician ; first part of last century.
STUMMER, RUDOLF VON (1866 — ). Austrian zoologist ; professor in Graz.

690 LIST OF AUTHOES

SUMNER, FRANCIS B. (1874 — ). American zoologist; Scrlpp's Institute for Biological

Research, La Jolla, Cal.

SUNDEVALL, CARL (b. 1801). Swedish zoologist; professor in Lund.
SURFACE, FRANK M. (1882 — ). American biologist; Maine Agriculture Experiment

Station, Orono.
SWAINSON, WILLIAM (1789-1855). English naturalist and traveler.

TAPPAN, BENJAMIN. American conchologist ; middle of last century.

TASCHBNBERG, ERNST (1818-1898). German zoologist and entomologist; professor
In Halle.

TATEM, J. G. English microscopist and protozoologist.

TBNNANT, DAVID H. (1873 — ). American zoologist; professor in Bryn Mawr.

TH£EL, JOHANN. Swedish zoologist.

THOMAS, ALGERNON P. W. English physician and parasitologist ; professor in Auk-
land, N. Z.

THOMPSON, CAROLINE B. (1869 — ). American zoologist; professor in Wellesley.

THOMPSON, CHARLES WTVILLB (1830-1882). Scotch zoologist; professor in Edin-
burgh ; sailed on the Challenger.

THOMPSON, D'ARCT W. (1860 — ). Scotch zoologist; professor in Dundee.

THOMPSON, JOHN V. (1779-1847). English zoologist and army surgeon.

THORELL, TAMERLAN. Swedish zoologist and arachnologlst ; middle of last century.

THORPE, V. G. English physician and microscopist ; latter half of last century.

TIEDEMANN, FRiEDRiCH (1781-1861). German zoologist; professor in Heidelberg.

TOPPE, OTTO. German zoologist ; assistant in Rostock.

TORREY, HARRY B. (1873 — ). American zoologist; professor in Reed College, Port-
land, Oregon.

TOTTEN, JOSEPH G. American conchologist ; middle of last century.

TREMBLEY, ABRAHAM (1700-1784). Swiss naturalist, and teacher in The Hague,
Holland.

TROUESSART, EDOUARD Louis (1842 — ). French zoologist; professor in Paris.

TROSCHEL, FRANZ (1810-1882). German zoologist; professor in Bonn.

TRYON, GEORGE W. (1838-1888). American conchologist; Academy of Natural
Sciences, Philadelphia.

TULLBERG, TYCHO. Swedish zoologist ; professor in Upsala.

TURNER, C. H. American zoologist ; teacher in Augusta, Georgia.

TURTON, WILLIAM (1762-1835). English conchologist and physician in Swansea.

D'UDEKBM, JULIUS. Belgian zoologist ; middle of last century.

VALENTIN, GABRIEL (1810-1883). German physician; professor in Breslau and

Berne.
VANATTA, E. G. American conchologist in the Academy of Natural Sciences,

Philadelphia.

VAN NAME, WILLARD G. (1872 — ). American zoologist resident in New Haven.
VAUGHAN, T. WAYLAND (1870 — ). American paleontologist and geologist; the U. S.

Geological Survey.

VEJDOVSKY, FR. (1849 — ). Bohemian zoologist; professor in Prague.
VERHOEFF, KARL WILHELM. Geftnan • zoologist resident in Cannstatt.
VERRILL, ADDISON E. (1839 — ). American zoologist; professor in Yale.
VOGT, CARL (1817-1895). German-Swiss zoologist; professor In Geneva.
VOSMAER, G. C. J. Dutch zoologist ; professor in Leyden.

WAGNER, FRANZ VON. Austrian zoologist ; professor in Prague.

WALCKENAER, CHARLES (1771-1852). French arachnologlst and zoologist; secretary
of the Paris Academy of Sciences.

WALKER, BRYANT (1856 — ). American conchologist and lawyer in Detroit.

WALLICH, NATHANIEL (1786-1854). Danish-English botanist, naturalist and physi-
cian in India.

WALTER, HERBERT E. (1867 — ). American zoologist; professor in Brown.

WALTON, L. B. (1871 — ). American zoologist; professor In Ken yon College, Ohio.

WARD, HENRY B. (1865 — ). American zoologist and parasitologist; professor in the
University of Illinois.

WICKEL, ADA L. American zoologist resident in Chicago.

LIST OF AUTHORS

WEBSTER, HARRISON E. American zoologist and president of Union College.

WEED, CLARENCE M. (1864 — ). American entomologist; instructor in State Normal
School, Lowell, Mass.

WEINLAND, CHRISTOPHER (b. 1829). German physician and zoologist.

WELCH, WILLIAM HENRY (1850 — ). American physician and bacteriologist ; professor
in Johns Hopkins.

WERNER, CARL (d. 1863). German zoologist.

WESTRING, NIKLAS (1797-1882). Swedish arachnologist.

WESTWOOD, JOHN O. (1805-1893). English entomologist and naturalist.

WEYSSB, ARTHUR W. (1867 — ). American zoologist; professor in Boston University.

WHEELER, WILLIAM M. (1865 — ). American zoologist and entomologist ; professor in
Harvard.

WHIPPLE, GEORGE C. (1866 — ). American sanitary engineer in New York City.

WHITMAN, CHARLES O. (1842-1910). American zoologist; professor in the Univer-
sity of Chicago.

WHITNEY, DAVID D. (1878 — ). American zoologist; professor in Wesleyan.

WEIGMANN, AREND (1802-1841). German zoologist; professor in Berlin.

WILDER, HARRIS H. (1864 — ). American zoologist; professor in Smith College.

WILHELMI, JULIUS. German zoologist resident in Berlin.

WILLEMOES-SULM, RUDOLF VON (d. 1876). German zoologist; sailed on the Chal-
lenger Expedition ; professor in Munich.

WILLEY, ARTHUR (1867 — ). English zoologist; professor in McGill University.

WILLIAMS, LEONARD W. (1875-1813). American zoologist and comparative anatomist ;
instructor in Harvard.

WILLIAMS, STEPHEN R. (1870 — ). American zoologist; professor in Miami
University.

WILSON, ALEXANDER (1766-1813). Scotch-American ornithologist resident in
Philadelphia.

WILSON, CHARLES B. (1861 — ). American zoologist; professor in State Normal
School, Westfleld, Mass.

WILSON, EDMUND B. (1856 — ). American zoologist; professor in Columbia.

WILSON, HENRY V. (1863 — ). American zoologist; professor in the University of
North Carolina.

WOLCOTT, ROBERT H. (1868 — ). American zoologist; professor in the University of
Nebraska.

WOLFF, EUGEN. German zoologist and entomologist ; decent in Frankfort.

WOOD, HORATIO C. (1841 — ). American zoologist and physician; professor in the
University of Pennsylvania.

WOODRUFF, LORANDE Loss (1879 — ). American protozoologist and zoologist; pro-
fessor in Yale.

WOODWORTH, WILLIAM McM. (1864-1912). American zoologist; Museum of Com-
parative Anatomy, Cambridge, Mass.

WRIGHT, R. RAMSEY (1852 — ). Canadian zoologist; professor in Toronto.

WRIGHT, THOMAS (1809-1884). Scotch physician and naturalist.

WRIGHT, WILLIAM (1735-1819). English naturalist and physician in the West Indies
and Edinburgh.

WRZESNIOWSKI, A. Polish zoologist and protozoologist ; middle of last century.

YARRELL, WILLIAM (1784-1856). English zoologist and merchant in London.

ZADDACH, ERNST (1817-1881). German zoologist; professor in Konigsberg.

ZEDER, J. G. H. German helminthologist and physician in Lichtenfels at the begin-
ning of the last century.

ZELINKA, CARL. Austrian zoologist ; professor in Czernowitz.

ZELLER, PHILLIP (1808-1883). German zoologist and entomologist.

ZENKER, FRIEDRICH VON (1815-1898). German anatomist and zoologist; professor
in Erlangen.

ZSCHOKKE, FRIEDRICH. Swiss zoologist ; professor in Basle.

ZURN, FRIEDRICH (1835-1900). German veterinary and parasitologist; professor
in Leipzig.

GLOSSARY

Abdomen. The most posterior body- division in arthropods and in some other

invertebrates.

Aboral. The side of the body opposite the mouth in a radiate animal.
Aciculum. A chitinous supporting rod in the parapodia of annelids.
Aoontium. A vibratile thread-like organ charged with nettle cells in certain

sea anemones.

Acraspedote medusa. A medusa without a velum. A scyphomedusan.
Acrocyst. A brood-chamber in certain campanularian hydroids.
Actinule. A larval form of certain hydroids.
Adaptive gills. Projections on certain opisthobranchs which function as gills,

but are not ctenidia.
Adductor muscle. A muscle which draws an organ towards the axis of the

body.

Algae. Very simple green plants.
Alimentary tract. The digestive canal, the organ which ingests, digests, and

absorbs the food.
Alternation of generations. The alternate succession of sexual and asexual

generations in a species of animals or plants.
Ambulacral feet. Tubular projections of the body wall with sucker discs at

their ends in echinoderms.
Ambulacral groove. The elongated groove on the oral side of the rays of the

starfish.
Ambulacral pores. Minute openings in the body-wall in the starfish and the

sea-urchin.

Ampulla. A sac-like projection of the ambulacral foot in echinoderms.
Anal feelers. Paired posterior appendages which are sensory in function.
Analogous. Having a similar function.
Antenna. A segmented sensory appendage on the head.

Antennal scale. The exopodite of the second antenna in certain malacostracans.
Antennal sinus. An indentation in the shell near the antennae of certain

ostracods.

Anterior* At or towards the front end of the body.
Anus. The posterior opening of the digestive canal.
Aorta. A large artery leading directly from the heart.
Aperture. The opening of a snail shell.
Apex. The tip of a snail shell.

Appendage. A projection from some part of the body.
Appendix. A short diverticulum usually of the intestine.
Archeocytes* Primitive cells in the mesoglea of sponges.
Aristotle's lantern. The dentary apparatus of the sea-urchin.
Artery. A blood vessel carrying blood away from the heart to the tissues.
Arthrobranch. A gill attached to the joint between the leg and the body in

crustaceans.

Articulate. Composed of a series of homologous segments.
Asexual. Reproduction by division or budding and not through the agency

of the sexes.

AtoTce. The anterior, sexless part of certain annelids.
Auricle. A chamber of the heart which receives the blood from the veins.

693

694 GLOSSARY

Autozooid. A feeding zooid in the Pennatulacea.

Avicularium. A structure shaped like a bird's head attached to the zooecium

in Bryozoa.

Axial organ. A glandular organ in the axial sinus in echinoderms.
Axial sinus. An elongated sac alongside the stone canal in echinoderms.

Basals. Calcareous interradial plates in the crinoid body.

Bilateral symmetry. Having the right and the left sides alike.

Bivalve^ A shell composed of two distinct and equivalent parts or valves.

Bladder worm. The larval stage of tapeworms.

Blastostyle. The reproductive polyp of a campanularian hydroid.

Body-cavity. An internal space in the body in which lie the viscera.

Body-wall. The outer portion of the body, which usually bounds the body-
cavity towards the inside.

Brachial. Relating to the arms.

Branchial. Eclating to the gills.

Branchial heart. A lateral heart in the squid which receives blood from one
of the gills.

Branchiate. Bearing gills.

Branchiostegite. Paired lateral folds of the body-wall in crustaceans which
protect the gills.

Brood-sac. A chamber in which the eggs develop in certain crustaceans.

Brown body. A round mass in certain bryozoans resulting from the disinte-
gration of the soft parts of the body.

Bud. An outgrowth of the body of an animal which becomes a new individual.

Byssus. Cuticular threads secreted by the foot of many pelecypods and used
to attach the shell.

CcBcum. A sac-like appendage of the digestive tract; a blind gut.

Calamistrum. A comb of stiff hairs on the fourth leg in certain spiders used
by the animal to make a band of silk which stretches across the web.

Calcareous. Formed of carbonate of lime.

Callus. A thickening near the umbilicus in certain snail shells.

Calyx. The body of a crinoid.

Canal. A tubular prolongation of the lip of the aperture containing the siphon
in many snail shells.

Carapace. The shell covering a portion or all of the cephalothorax in crus-
taceans.

Cardinal teeth* The hinge teeth beneath the umbo in a bivalve shell.

Carina. The median dorsal shell in barnacles.

Cartilage. The internal portion of the ligament in certain bivalve shells.

Cellulose. The woody cell-wall of plant cells and also of certain cells in the
tunic of tunicates. <

Central teeth. In the radula of mollusks the central row of teeth.

Centrodorsal. The basal portion of a non-sessile crinoid.

Cephalic gland. A tubular organ at the anterior end of nemerteans.

Cephalont. A sporozoon, when attached.

Cephalothorax. A body-division formed by the fusion of the head and the
thorax in arthropods.

Cerata. Dorsal projections in opisthobranchs.

Ceratine. A horn-like substance forming the skeleton in certain corals.

Cercariaj A larval form of trematodes.

Cercus. A paired sensory projection at the posterior end in certain inverte-
brates.

Cerebral tube. A sense organ of sipunculids.

Chelate. Having forceps-like pincers.

GLOSSARY 695

Cheliped. The large grasping claw in many crustaceans.

Chitin. A hard and very resistant substance present in the cuticula of many

arthropods.

Chlorophyll. The green coloring matter of plants.
Chromatophores. Colored pigment cells.
Cilia. The numerous vibratory projections on both the inner and the outer

surfaces of certain animals.
Cirrus. A filamentous, sensory appendage of annelids; a protrusile copulatory

organ of flatworms.
Clitellum. A thickened glandular region on oligochaets which secretes the

cocoon.
Cloaca. A tubular or sac-like space which receives the discharge of various

organs.

Cnidoblast. A stinging cell in Cnidaria which contains the nematocyst.
CnidocU. A minute spine projecting from a nettle cell into the water.
Cocoon. A case containing one or more developing animals.
Caelom. The body-cavity.

Caenenchym. The soft parts of an alcyonarian colony.
Collar. The ventral edge of the mantle in gastropods and cephalopods; the

part of the body of Balanoglossus between the proboscis and the trunk.
Collar cell. A flagellate cell with a high membrane around the base of the

flagellum.

Colon. A division of the intestine.
Columella. The axis of a spiral snail shell.

Complementary male. A minute accessory male animal in certain barnacles.
Compound eye. An eye made up of a number of separate elements, or omina-

tidia, in arthropods.
Conjugation. The fusion of two protozoans and interchange of nuclear

matter.
Connective tissue. A tissue whose principal function is to support and hold

in place other tissues and organs.
Coxa. The proximal segment of an arthropod's leg, by which it articulates

with the body.

Coxal plate. A plate in the ventral surface of Acarina.
Craspedote medusa. A medusa with a velum, a hydromedusan.
Cribellum. A plate with spinning tubes in front of the spinnerets in some

spiders.
Cribriform organs. Parallel, vertical rows of thin calcareous plates in the

margins of the arms of certain starfish.
Crop. A dilated portion of the O3sophagus.
Ctenidium. The molluscan gill.

Cuticula. The outer layer of the integument of most invertebrates.
Cyst. A capsule containing an animal usually in a state of suspended anima-
tion ; a capsule containing a foreign or inert body imbedded in some animal

tissue.
Cysticercoid. A minute bladder worm in which the scolex completely fills the

cyst.
Cysticercus. A bladder worm in which the cyst contains one or more scolices

and a fluid.

Dart sac. A part of the genital tract of certain pulmonate snails.

Dentary apparatus. The five teeth and their supporting structure in the sea-
urchin.

Desor's larva. A nemertean larval form.

Development. The series of changes in the early life of an animal by which
it passes from the condition of a fertilized egg to that of the adult.

696 GLOSSARY

DimorpJiism. The condition in which a species exists in two distinct forms,

as, for instance, male and female.

Dioecious. Having the two sexes in two separate individuals.
Dissepiment. The partitions between the somites in annelids.
Distal. The position of a part of an organ away from the point of attachment

— opposed to proximal.

Diverticulum. A sac-like projection of a tubular organ.
Dorsal. On or towards the back.
Dorsal lamina. A ciliated ridge in the mid-dorsal line of the pharynx in the

ascidean.

Ectocyst. The zooecium or outer wall of a bryozoan's body.

Ectoderm. The outermost layer of cells in the Coelenterata.

Ectosaro. The outermost layer of non-granular protoplasm in protozoans.

Elytra. The imbricated scales on the back of certain annelids; the wing-covers
of beetles.

Embryo. A young animal which is passing through its developmental stages,
usually within the egg membranes or in the maternal uterus.

Encyst. The act of an animal in forming a cyst about itself.

Endopodite. . The innermost of the two terminal branches of the typical
crustacean leg. •

Endostyle. A ciliated, glandular groove in the midventral line of the pharynx
of tunicates and of Amphioxus.

Entoderm. The innermost layer of cells in the Coelenterata.

Entosarc. The interior granular protoplasm in protozoans.

Ephippium. The shell in which the winter eggs of Cladocera are often con-
tained.

Ephyra. A youthful stage in the growth of a scyphomedusan.

Epigynum. A plate over the genital orifice in the female spider.

Epiphragm. The disc of calcified slime with which a land pulmonate can close
the opening of its shell.

Epipodium. A ridge along the side of the molluscan foot.

Epistome. A projection above the mouth in certain bryozoans.

Epitoke. The posterior sexual part of the body of certain annelids.

Erineum. A pathological plant-growth caused by certain mites.

Exopodite. The outermost of the two terminal branches of the typical crusta-
cean leg.

Extensor muscle. A muscle that extends an organ.

Extremity. A paired lateral or ventral appendage of the body of an animal,
used primarily for locomotion, although in many cases having secondarily
some other function.

Exumbrella. The aboral side of a medusa.

Fertilization. The union of the spermatozoon and the ovum.

Flagellum. A vibratory thread-like projection of certain cells; the terminal
portion of the antennae in crustaceans.

Flame cell* The terminal cell of an excretory tubule in the kidney of Plathel-
minthes.

Flexor muscles. A muscle that bends an organ.

Food vacuole. A globule of water containing food particles in protozoans.

Frontal appendage. A pair of extra appendages between the second antennae
in certain Branchiopoda.

Frontal organ. Sensory organs near the front end of certain nemerteans.

Funiculus. A mesenteric strand connecting the stomach pouch with the body-
wall in bryozoans.

Funnel. The siphon of a cephalopod.

Furca. A pair of projections at the hinder end of the "body of copepods.

GLOSSARY 697

Ganglion. An aggregation of nerve cells.

Gastrovascular space. The central cavity in Cnidaria and Ctenophora.

Gastrozooid. A feeding zooid of a siphonophore colony.

Gemmule. A capsule in fresh-water sponges containing archeocytes which live

through the winter and in the spring form the starting point of a new

sponge-colony.
Gastrula. A stage in the development of the embryo in which two cell layers

are present, ectoderm and entoderm.

GUI. An organ for the breathing of air contained in the water.
Gill-filament. Ciliated vertical ridges on the surface of the gills of pelecypods.
Girdle. An integumental fold in chitons surrounding the shell.
Gizzard. A portion of the alimentary tract in certain animals with thickened

muscular walls in which the food is chewed.
Glochidium. The larval form of Anodonta and Unio which lives a parasitic

life in the skin of fishes.
Gnathopod. A grasping claw in amphipods.
Gonangium. The cuticular covering or gonotheca of the blastostyle in cam-

panularian hydroids.

Gonosome. The medusoid stage of a hydromedusan.
Gonotheca. The cuticular outer covering of the blastostyle.
Gonozooid. The reproductive zooid of a siphonophore colony.

Haemal. Pertaining to the blood system.

Haller's organ. A sense organ on the anterior pair of legs in certain ticks.

Head. The anterior body-division of the higher animals.

Heart. A muscular tubular or saccular organ which propels the blood through
the arteries.

Hectocotylus arm. One of the arms in the male in many cephalopods used to
transfer sperm to the female.

Hermaphroditic. Having the two sexes united in one animal.

Hinge ligament. The flexible portion of a bivalve shell which joins the two
valves.

Homologous. Having had a similar origin.

Host. The animal which harbors a parasite.

Hydranth. An individual feeding-polyp in a hydroid colony.

Hydrocladium. Small branches in the Plumulariidae bearing the polyps.

Hydrocaulus4 The stem of a hydroid colony.

Hydroid. The sessile, asexual generation of the Hydromedusae and Scypho-
medusae.

Hydrorhiza. The root-like projection of a hydroid colony by which it is
attached.

Hypodermis. The cellular layer which forms the inner portion of the integu-
ment of most invertebrates and secretes the cuticula.

Hypophysis. A ventral projection of the brain in vertebrates.

Hypopus. The youthful form of certain mites.

Hypostome. The projection of a hydroid 's body which bears the mouth.

Infrabasals. Calcareous plates between the basals in certain crinoids.

Infundibulum. A longitudinal fold of the pharyngeal wall of ascidians.

Insertion plate. The portions of the shell of chitons beneath the girdle.

Integument. The outer covering of an animal; in most invertebrates it con-
sists of an outer cuticula and an inner hypodermis.

Interlamellar partitions. Vertical walls which join the two lamellae of a pele-
cypod's gill.

Intermediate host. The animal which harbors the larval form only of ; a
parasite.

698 GLOSSAEY

Interray* One of the divisions of the radiate body of echinoderms.
Intestine. The division of the digestive tract in which absorption goes on.
Introvert. The anterior part of a sipunculid, which can be invaginated.

Keber's organ. An excretory organ in pelecypods.
Kidney. An excretory organ.

Labmm. The under lip of many arthropods.

Lamella. A leaf- or plate-like structure.

Larva. A young animal which has left the egg and is leading a free life, but
which has not yet completed its development.

Lateral. A position to the right or left of the median line.

Lateral teeth. In the radula of mollusks the teeth on each side of the cen-
trals; in pelecypods the hinge-teeth either anterior or posterior to the
cardinals.

Ligament. The elastic band joining the two valves of a pelecypod's shell.

Lip. The margin of the aperture of a snail shell.

Lithocysti A marginal sense-organ in campanularian medusae.

Liver. A digestive gland.

Lophophore. A circular or horseshoe-shaped ridge bearing tentacles in Bryozoa,
Braehiopoda and Phoronidea.

Lorica. The shell enclosing the body in many rotifers.

Lumen. The cavity within a tubular organ.

Lunule. A depressed area in front of the umbo in certain pelecypods.

Lycophore. The ten-hooked embryo of the Cestodaria.

Macronucleus. The large nucleus of an infusorian.

Madreporite. The porous plate through which fluids enter the ambulacral

system.

Malpighian tubes. The kidney of insects and many arachnids.
Mammary organ^ An elevation in the vestibule of certain entoproct bryozoans

which nourishes the embryos.

Mandible. The anterior pair of mouth-parts in arthropods.
Mantle. The integumental fold in mollusks and brachiopods which secretes the

shell; the body- wall of ascidians beneath the tunic.

Manubrium. The projection of a medusa's body which bears the mouth.
Marginal teeth. In the radula of mollusks the teeth at the side of the laterals.
Mastax. The muscular pharynx of a rotifer.

Maxilla. The paired mouth-parts immediately behind the mandibles in arthro-
pods.

Maxillipeds. The anterior thoracic appendages in crustaceans and centipeds.
Medusa. A free-swimming jelly-fish.

Medusoid. The sexual generation of the Hydromedusae and Scyphomedusae.
Megascleres. The larger spicules in sponges which form the principal skeletal

support.
Mesentery. A lamella which supports some one of the viscera; in Scyphozoa

and Anthozoa a lamella extending from the body-wall into the gastrovas-

cular space.
Mesoglea. The middle tissue between the ectoderm and entoderm in Coelen-

terata.

Metacnemes. The secondary mesenteries of Anthozoa.
Metamere. One of the serial, homologous body-segments, together with ltd

appendages, which form the body of an articulate animal.
Metapodium. The hinder part of the molluscan foot.
Metasoma. The primitive segmented trunk of an articulate animal.
Metastomvum. The posterior portion of the head of an annelid.

GLOSSAET 699

Metasoa. The division of the animal kingdom comprising the many-celled

animals.

Micronucleus. The smaller of the nuclear bodies in inf usorians.
Microscleres. The minute spicules in sponges.
Miracidiumj The youngest larval stage of trematodes.
Monoecious. Having the two sexes united in one individual.
Mother-of-pearl. The inner layer of the shell of mollusks.
Moult. To shed the cuticula or the outer portion of it.
Mouth-parts. The masticatory appendages on the head of arthropods.

Nauplvus. A young larval form of many crustaceans, especially entomostracans.
Nematocyst. The stinging organ in the Cnidaria which is within the cnidoblast.
Nephridium. A urinary tubule in annelids.

Nephrostome. The ciliated opening of a nephridium into the body-cavity.
Nerve commissure. A nerve connecting the two members of a pair of ganglia.
Nerve connective. A nerve connecting two ganglia not of the same pair.
Nettle cell. The stinging organ or nematocyst in the Cnidaria.
Neuropodium. The ventral division of the parapodium of an annelid.
Nidamental glands. The large glands which secrete the egg-capsules in the

squid.
Notochord. A cylindrical rod formed in the young embryo along the mid-dorsal

line of the digestive tube and ventral to the nervous system in chordates.
Notopodium. The dorsal division of the parapodium of an annelid.
Nucleus. A spheroidal body in a cell, the center of its activities.

Ocellus. A minute primitive eye in arthropods.

(Esophagus. The gullet, the division of the digestive canal leading from the

pharynx to the stomach.

Ommatidvum. A single element of the compound eye of an arthropod.
Onchosphere. The six-hooked embryo of tapeworms.

Operculum. A plate closing an opening or covering some other structure.
Ooecwm. A structure in Bryozoa in which the embryo develops.
Oral. The side of the body containing the mouth in a radiate animal.
Oral groove. A groove leading to the mouth in ciliate infusorians.
Organs of Cuvier. Glandular tubes extending from the rectum in holothurians.
Organ of JLeber. An excretory organ in pelecypods.
Orthoneurous gastropods. Snails in which the pleuro-visceral nerve connectives

are not crossed.

Osculum. The cloacal opening in sponges.

Ossicles. The calcareous plates in the body-wall of echinoderms.
Otocyst. An organ of hearing.

Otoporpae. Thickenings of the ectoderm at the lithocysts in Narcomedusae.
Outer lip. The portion of the lip of the aperture of a snail shell away from

the axis.

Ovary. The female sexual gland.
Ovicell. A brood-chamber or oo3cium in bryozoans.
Oviduct. The tube leading from the ovary towards the outside.
Ovipositor. The organ by means of which certain arthropods deposit their eggB.
Ovum. The female sexual cell, the egg.

Pallets. Small calcareous plates in the siphons of Teredo.

Pallial line. The line along which the margin of the mantle is attached to the

shell in pelecypods.
Pallial sinus. The indentation in the pallial line, caused by the insertion of

the siphonal retractor muscle.
Palp. A sensory organ near the mouth.

700 GLOSSARY

Pancreas. A digestive gland in the squid.

Papulae. Delicate projections of the body-wall in the starfish.

Paramylum. A granular substance resembling starch in Euglena.

Parapodium. The appendage of annelids.

Parasite. An animal which lives in or on another and feeds upon its nutritive
fluids.

Parenchyma. A vesicular connective tissue which fills the body-cavity of flat-
worms and leeches.

Parietal lip. The side of the aperture of a snail shell towards the axis.

Parietal tooth. A tooth on the parietal lip.

Parthenogenesis. Eeproduction by means of unfertilized eggs.

Paxillae. Calcareous rods surmounted by minute spines on the aboral surface
of certain starfish.

Pedicellariae. Minute pincer-like organs present on the external surface of
certain echinoderms.

Pedipalps. The second pair of appendages in arachinids.

Peduncle. The stalk by which a sessile animal or a sessile organ is attached.

Pen. The shell of the squid.

Pericardium. The membrane surrounding the heart.

Periopods. The thoracic appendages posterior to the maxillipeds in crusta-
ceans.

Periostracum. The outer layer of the molluscan shell.

Periphery. The outer surface of a body.

Periproct. The region immediately around the anus.

Perisarc. The cuticular outer covering of a hydroid.

Peristome. A membrane surrounding the mouth in echinoderms; the outer
lip of the aperture of a snail shell.

Peristomial gills. Gills on the peristome of sea-urchins.

Peristommm. The posterior portion of the head in most annelids.

Peritoneum. The membrane lining the body-cavity.

Peritreme. The stigmal plate in certain mites.

Peronia. Thickenings of the ectoderm at the base of the tentacles in Narcome-
dusae.

Petaloid area. The petal-like arrangement of the aboral ambulacra! pores in
certain sea-urchins.

Pharynx. The division of the alimentary tract immediately back of the mouth.

Phragmocone. The chambered portion of the cephalopod shell.

Pinnules. The small branches of the arms of crinoids.

Plankton. A collective term referring to all small forms of life in the surface
waters of the sea or fresh water.

Planula. The cilated free-swimming larva of many Cnidaria.

Pleopod. An abdominal appendage in crustaceans.

Plerocercoid. A tapeworm larva resembling the scolex of the adult worm.

Plerocercus. A tapeworm larva consisting of the scolex and some of the pro-
glottids.

Pleurobranch. A gill attached to the body -wall in crustaceans.

Pluteus. The larva of a sea-urchin or a brittle star.

Podia. The ambulacral appendages of echinoderms.

Polian vesicle. A sac projecting from the ring canal of echinoderms.

Polymophism. The condition in which an animal species exists in several dis-
tinct forms.,

Polyp. A sessile individual in Cnidaria or Bryozoa.

Posterior. At or towards the hinder end of an animal.

Proboscis. A prehensile organ in certain worms, usually a portion of the
pharynx; the beak-like mouth-parts of certain arthropods.

Proglottid. A tapeworm segment.

GLOSSARY 701

Proostraoon. The grooved or trough-like shell of certain cephalopoda.

Propodium. The anterior portion of the molluscan foot.

Prosoma. The primitive head of annelids.

Prostate gland. The gland which secretes the fluid in which the spermatozoa

are suspended.

Prostomium. The anterior portion of the head of annelids.
Protopodite. The basal segment of a crustacean's leg.

Protractor muscle^ A muscle which extends the organ to which it is attached.
Proximal. The position of a part of an organ towards the point of attachment

. — opposed to distal.

Pseudopodium. A retractile locomotory process in sarcodins.
Pseudoscolex. The anterior end of certain tapeworms which lack a scolex.
Pseudostigmatic organs. A pair of club-shaped bristles on oribatid mites.
Pulsating vacuole. A globule of excretory fluid in many protozoans.
Pyrenoids. Deeply staining bodies in the chromatophores of Euglena.

Rachis. The upper portion of the Pennatulacea, containing the polyps.

Radial symmetry. Having the parts or organs arranged symmetrically about a
common center.

Radials. Calcareous plates in crinoids above the basals.

Eadius. One of the rays, the five main divisions of the echinoderm body.

Radula., The band of calcareous teeth in the pharynx of most mollusks.

Ray. One of the main divisions of the radiate body of echinoderms.

Receptaculum seminis. A receptacle for sperm in the female animal.

Rectum. The posterior division of the digestive tract.

Respiratory tree. The paired branched diverticula of the rectum of holo-
thurians.

Retractor muscles. Muscles which draw an organ towards its point of attach-
ment.

Rhinophores. The posterior pair of tentacles in many opisthobranchs.

Rhopalia. The sense organs or tentaculocysts of scyphomedusans.

Ring canal. The central portion of the ambulacral system in echinoderms.

Rostellum. A projection of the scolex of many tapeworms bearing hooks.

Rostrum. A projection of the carapace in crustaceans; the cylindrical terminal
portion of a belamnite shell.

Salivary glands^ Digestive glands at the anterior end of the digestive tract.

Scleroblasts. The cells of the mesoglea of sponges which secrete the spicules.

Scolex. The anterior end of a tapeworm containing the organs of attachment.

Scutum. A shield on the dorsal surface of ticks.

Scyphistoma. The hydroid generation of the Scyphomedusae.

Secondary flagellum. A small branch of the tentacle in certain crustaceans.

Segment. One of a number of serial divisions of an animal's body or of an

organ.
Septum. A plate forming a division wall between two spaces; one of the

radial calcareous plates of a stony coral.
Sessile. Fixed to one place, without locomotory powers — of an animal; not

on a stalk or stem — of an organ.
Seta. A bristle.

Sexual. Eeproduction through the agency of the two sexes.
Siphon. The organ through which water enters or leaves the mantle cavity in

mollusks and ascidians.
Siphonal canal. A tubular prolongation of the lip of the aperture of many

snail shells to enclose the siphon.
Siphonoglyph. A ciliated groove at one end of the mouth in the Anthozoa.

702 GLOSSARY

Siphonozooid. Eudimentary zooids through which water flows into the ento-
dermal canals in the Pennatulacea.

Siphuncle. The tubular portion of a nautilus' body which extends through
the chambers.

Somite. One of the serial, homologous body-segments which form the body of
an articulate animal.

Spermatheca. A sac for the storing of sperm in the female animal, a seminal
receptacle.

Spermatophore. A capsule or mass of spermatozoa.

Spermatozoon. The male sexual cell.

Sperm-duct. The vas deferens.

Sperm-sac. A sac for the storing of sperm in the male animal, a seminal
vesicle.

Spicule. A minute calcareous or silicious body in sponges and echinoderms.

Spinnerets. Appendages at the hinder end of a spider containing the openings
of the silk glands.

Spiracle. An external opening in the tracheal system in arthropods.

Spire. The portion of a snail shell above the large lowest whorl.

Spongin. The substance composing the elastic fibers of a sponge.

Spongioblasts. The mesoglea cells which form the elastic fibers of a sponge.

Sporont. The sporulating stage of a sporozoan.

Sporosac. A sessile medusoid, one which remains attached to the parent
hydroid.

Statoblast. Disc-like buds in fresh-water Bryozoa which live through the
winter.

Sternum. The ventral portion of the cepholothorax surrounded by the legs in
spiders.

Stigmal plate. A plate surrounding the spiracle in certain mites.

Stigmata. The respiratory openings in the pharyngeal wall in ascidians.

Stomach. A division of the digestive tract in which digestion goes on.

Stomach pouch. A diverticulum of the stomach.

Stone canal. A tube joining the madreporite with the ring canal in echino-
derms.

Streptoneurous gastropods. Snails in which the pleuro-visceral connections cross
each other.

Strobilation. The process of terminal budding.

Stylets. Calcareous needles in the proboscis of hoplonemerteans.

Subchelate. A pinching claw formed by the bending of the terminal segment
over the next one.

Subcuticula. The tissue beneath the cuticula in trematodes and cestodes.

Subgenital pocket. A pocket in the subumbrella of many scyphomedusans.

Subneural gland. A glandular body in ascidians.

Subumbrella. The oral surface of a medusa.

Summer eggs. Thin-shelled eggs produced by parthenogenetic females of cer-
tain crustaceans, usually in the summer.

Supporting layer. The non-cellular layer between the ectoderm and entoderm
in Hydrozoa.

Swimmeret. The abdominal appendage of a crustacean, a pleopod.

Symbiotic. The living together of two dissimilar organisms, each being depend-
ent upon the other.

Systemic heart. The median heart of the squid.

Tactile. Relating to the sense of touch.

Tarsus. The segmented foot of an arthropod.

Telson. The terminal segment of a crustacean or arachnoid.

Tentacle. An elongated tactile organ.

GLOSSARY 703

Tentaculocyst. The sense organs of the Scyphozoa.

Terminal. Towards or at the posterior or the distal end.

Test. The tunic of the ascidian; the rigid shell of the sea-urchin.

Testis. The male sexual gland.

Theca. The outer wall of the calcareous cup of a stony coral.

Thorax. The body-division just anterior to the abdomen.

Tiedemann's vesicles. Minute diverticula of the ring canal of the starfish.

Tooth papillae. Projections from the jaw of a brittle star.

Trachea. A respiratory tube in air-breathing arthropods.

Trichocyst. A cyst containing a defensive bristle in the ectosarc of infusorians.

Trochophore. A larval form common to annelids, mollusks, and other animals.

Trophi. The paired jaws in the mastax of rotifers.

Trophosome. The hydroid stage of hydromedusans.

Trophozooid. The youthful stage of a fungoid coral.

Tunic. The outer cuticular covering of tunicates.

Umbilicus. A depression or cavity at the axial base of a snail shell.

Umbo. The protuberance above the hinge on the shell of a pelecypod.

Ureter. A tube forming the outlet of the kidney.

Uropod. The sixth swimmeret of certain crustaceans which forms the swim-
ming tail.

Uterus. A dilated portion of the oviduct in which the egg or the developing
animal may be held.

Vagina. The terminal division of the female reproductive tract.

Vas deferens. A duct leading from the testis towards the external opening;
the sperm-duct.

Vegative organs. Those organs which have to do with the processes of nutri-
tion, growth, and the expulsion of wastes.

Vein. A vessel which brings blood towards the heart.

Velarium. The false velum of Cubomedusae.

Veliger larva. The larva of many gastropods.

Velum. The circular muscular locomotory membrane of a hydromedusan.

Ventral. On or towards the underside of an animal.

Ventricle. A chamber of the heart from which blood is sent over the body.

Vesicula seminalis. A sperm-sac in the male animal.

Vestibule. The depression within the lophophore in entoproct bryzoans.

Vibraculum. Whip-like defensive organs in many bryozoans.

Viscera. The organs within the body-cavities.

Visceral mass. The compact group of organs comprising the principal viscera
in mollusks.

Winter eggs. Thick-shelled eggs produced by parthenogenetic females after
fertilization, usually in the fall.

Zodchlorellae. Single-celled algae which live symbiotically with some inverte-
brates.
Zocecium. The outer cuticular covering of a bryozoan.

INDEX

This Index includes the names of species, genera and all other systematic
groups, and also the names of anatomical structures. Specific names begin with
a small letter and each is followed by the name of its genus in parentheses. All
other names and terms begin with capital letters. Specific and generic names
which appear in italics are synonyms.

In the case of an anatomical structure the page referred to is the one on
which a definition or description of the structure will be found.

In the case of a species, genus, or other systematic group the page referred
to is the one on which the principal description of it will be found.

ABALONES, 531.

abditum (Pisidiura), 587.

Abdomen, in arthropods,

323; in ascidians, 668.
Abdominalia, 362.
abdominalis (Phryxus),

381.

abietina (Abietinaria), 107.
Abietinaria, 107.
Aboral surface, 614.
Abothrium, 195.
Acalephae, 89.
Acanthobdella, 316.
Acanthocephala, 228.
Acanthochitidae, 489.
Acanthocystis, 23.
Acanthodoris, 502.
Acarina, 436.
Acartia, 345.
Acephala, 481.
Acephalina, 46.
acerosa (Gorgonia), 136.
Acetabulum, 179.
aceti (Anguillula), 217.
achetae-abbreviatae (Gre-

garina), 44.

acicula (Turritella), 548.
Aciculum, 283.

Acineta, 68.

Acinetidae, 68.

Acmsea, 530.

Acmseidae, 530.

Accela, 158.

Acontia, 133.

Acotylea, 169.

Acraspedote medusa, 88.

Acrocyst, 104.

Acroperus, 336.

Acropora, 146.

Acroporidae, 146.

Acrosoma, 426.

Acteon, 496.

Acteonidae, 496.

Actiniaria, 139.
Actinocephalidae, 45.
Actinodendron, 138.
actinoides (Thysanosoma).

199.

Actinololja, 144.
Actinometra, 622.
Actinophrys, 22.
Actinopoda, 648.
Actinosphaerium, 23.
Actinotrocha, 270.
actinotus (Hoplorhynchus),

45.

Actinozoa, 132.
Actinules, 103.
aculeata (Anomia), 570.
aculeata (Anursea), 239.
aculeata (Centropyxis), 18.
aculeata (Harmothoe), 285.
aculeata (Ophiopholis),

636.

aculeata (Pennatula), 137.
aculeata (Philodina), 235.
aculeus (Rissoa), 541.
acuminata (Candona), 355.
acuminata (Difllugia), 17.
acuminata (Metopidia),

242.

acus (Euglena), 32.
acuta (Hircinia), 85.

Adamsia, 144.

Adaptive gills, 495.

Adinida, 39.

^Ega, 375.

^Egidae, 374.

JEginella, 372.

JEginidae, 121.

^Eolidia, 503.

^olididae, 503.

^Eolidioidea, 503.

JEolis, 503.

^Eolosoma, 305.

2Eolosomatidae, 305.

705

ffiqualis (Mediaster), 627.
^Equorea, 116.
^Equorea forskalea, 88.
/Equorea tenuis, 88.
-SSquoreidae, 116.
^Esthetes, 485.
sestiva (Labidocera), 345.
(Bstivalis ( Dendryphantes ) ,

435.

JEtea, 252.
^Eteidae, 252.
affinis (Cambarus), 392.
afflnis (Cyclosalpa), 662.
afflnis (Diclidophora), 177.
affinis (Gebia), 389.
affinis (Trophonia), 300.
Agalmidae, 124.
agassizi (Gorgonocepha-

lus, 638.
agassizi (Physcosoma),

275.

Agelena, 430.
Agelenidae, 430.
aggregata (Styela), 666.
agile (Nectonema), 228.
agilis (Caddo), 411.
agilis (Fredericia), 308.
agilis (Hahnia), 431.
agilis (Lumbricillus), 307.
agilis (Monocystis), 46.
agilis (Orchestia), 367.
Aglantha, 120.
Aglaura, 120.
Aglauridae, 119.
agrestis (Agriolimax), 527.
agricola (Geonemertes),

210.

Agriolimax, 527.
Akeridae, 497.
alarius (Phrurolithus),

430.

Alasmidonta, 582.
alata (Bolinopsis), 153.

706

INDEX

alata (Neocomatella), 623.
alatum (Hemistomum),

188.

alba (Eteone), 286.
alba (Fredericia), 307.
albicans (Ocypoda), 399.
alblda (^Equorea), 116.
albida (Glottidia), 267.
albidum (Leptoclinum) ,

671.

albldus (Cyclops), 347.
albidus (Enchytrseus), 307.
alboflavicans (Megalo-

trocha), 234.

albolabris (Polygyra), 521.
albulus (Stichaster), 631.
albus (Trachydermon), 488.
alcicornls (Millepora), 93.
Alclppe, 362.
Alcippidae, 362.
Alcyonacea, 134.
Alcyonaria, 133.
Alcyonidiidae, 259.
Alcyonldium, 259.
Alcyoniidae, 134.
Alcyonlum, 134.
Alderia, 505.
Aleurobius, 442.
Alona, 337.
Alloeocoela, 164.
Allolobophora, 313, 314.
Allorchestes, 367.
Allurus, 314.
Alpheus, 388.
alta (Janira), 378.
alternata (Pyramidula),

522.
Alternation of generations,

70, 660.

alternatum (Bittium), 546.
alvea (Acmaea), 530.
alveola ta (Euglypha), 19.
Amaroucium, 670.
Amathia, 260.
Amaurobius, 418.
ambignum (Spirostomum),

58.

Amblyomma, 446.
Ambulacral appendage,

616.

Ambulacral foot, 616.
Ambulacral groove,

619, 623.

Ambulacral system, 616.
American hookworm, 223.
americana (Bertia), 198.
americana (Cellepora),

259.

americana (Glycera), 291.
americana (Odinia), 633.
americana ( Pedicellina ) ,

248.

americana (Styela), 666.
americana (Uroglena), 35.
americanum (Amblyomma),

446.
americanus (Arrhenurus),

452.
americanus ( Cerianthus ) ,

140.

americanus (Cyclops), 346.
americanus (Epizoan-

thus), 141.
americanus (Homarus),

389.

americanus (Necator), 223.
americanus (Rhyncobolus),

291.

Amicula, 489.
Ammonites, 606.
Ammonoidea, 606.
Ammotheidae, 459.
Ammotrypane, 298.
Amnicola, 542.
Amoeba, 16.
Amoebida, 15.
Amosbidae, 15.
Ampelisca, 368.
Ampeliscidae, 368.
Ampharete, 296.
Ampharetidae, 296.
Amphictenidae, 297.
Amphidinium, 41.
Amphidisc, 80.
Amphileptus, 53.
Amphilina, 192.
Amphimerus, 185.
Amphineura, 482.
Amphioxus, 673.
Amphipholis, 637.
Amphipoda, 365.
Amphiporidae, 210.
Amphiporus, 210.
Amphisia, 62.
Amphistomata, 182.
Amphithoe, 371.
Amphithoidae, 371.
Amphitrite, 295.
Amphiuridae, 636.
amphora (Campanularia),

111.

amphora (Tintinnus), 60.
Amphoriscidae, 77.
Amphoriscus, 77.
Amphoroides, 45.
amplicava (Gorgodera),

186.

Ampulla, 616.
ampulla (Cyphoderia), 19.
Ampullaria, 545.
Ampullariidae, 545.
amylophagus (Phyllomi-

tus), 30.
Anachis, 557.

Analges, 441.
Analgesidae, 440.
Anaperus, 159.
anatifera (Lepas), 361.
Anatinacea, 600.
Anatinidae, 601.
Anchylostoma, 223.
ancillaria (Physa), 511.
Ancula, 501.
Ancylidae, 513.
Ancylus, 513.
Androgonidia, 39.
Anelasma, 360.
anguillae (Echinorhyn-

chus), 229.
Anguillula, 217.
Anguillulidae, 216.
anguina (J^tea), 252.
angulata (Epeira), 425.
angulata ( Ophiothrix ) ,

637.

angulata (Scalaria), 535.
angulatus (Amphiporus),

211.

Anisonema, 33.
Annelid worms, 277.
Annelida, 277.
Annelides errantes, 279.
Annelides hirudineae, 279.
Annelides lumbricineae,

279.

Annelides nereideae, 279.
Annelides serpuleae, 279.
Annelides terricoles, 279.
Annelides tubicoles, 279.
annularis (Orbicella), 148.
annulata (Cambala), 470.
annulata (Cribrilina), 256.
annulatum (Calliostoma),

533.
annulatus (Gammarus),

369.

annulatus (Limnias), 234.
annulatus ( Margaropus) ,

446.
annulosa ( Taphrocampa ) ,

238.

Anodonta, 581.
Anodontoides, 583.
anodontoides (Lampsilis),

580.

anomala (Crania), 268.
Anomia, 570.
Anomiidae, 570.
Anomura, 392.
Anopheles, 47.
Anoplocephala, 198.
Anoplocephalidae. 197.
Anoplodactylus, 460.
Anoplophrya, 57.
anser (Dileptus), 53.
anserifera (Lepas), 361.

INDEX

707

Antedon, 622.
Antedonidae, 621.
Antenna (in arthropods),

323.

Antennal scale, 363.
Antenna! sinus, 357.
antennina (Antennularia),
. 109.

Antennularia, 109.
Antennule, 327.
Anterior canal, 529.
Anthobothrium, 196.
Anthomedusae, 93.
Anthophysa, 28.
Anthozoa, 132.
Anthuridae, 374.
antillarum (Centrechinus),

643.

Antipatharia, 139.
Antipathes, 139.
Antipathidae, 139.
Ant-like spider, 436.
Anuraea, 239.
Anurseidae, 239.
Aperture, of snail shells,

492, 506.

Apex, of snail shells, 506.
Aphanostoma, 159.
Aphrodita, 284.
Aphroditidae, 284.
Aphrothoracida, 22.
apicata (Stomatoca), 98.
apiculata (Chsetopleura),

487.

Aplacophora, 483.
Aplexa, 511.
Aplysia, 499.
Aplysiidae, 499.
Aplysina, 85.
Aplysinidae, 85.
Aplysioidea, 499.
Apodidae, 331.
Aporosa, 147.
Aporrhais, 549.
Appendicularia, 658.
Appendiculariidae, 658.
appendiculatus ( Diophrys ) ,

63.
appendiculatus

(Hemiurus), 187.
appendiculatus

(Polygordius), 281.
Apus, 331.
aquatica ( Limnochares ) ,

448.

aquaticus (Gordius). 227.
Arabella, 290.
Arachnida, 402.
Arachnoidea, 400.
Araneae, 413.
Araneida, 413.
Araneus, 425.

Arbacia, 643.
Arbaciidae, 643.
arborea (Zonitoides), 526.
arborescens (Dendronotus),

501.

arbuscula (Chalina), 82.
arbuscula (Zoothamnium),

66.

Area, 571.
Arcella, 18.
Arcellidae, 17.
Archeocytes, 73.
archeri (Diplophrys), 21.
Archiannelida, 280.
architecta (Phoronis), 271.
Architeuthis, 610.
Arcidae, 570.
arctica (Cyanea), 130.
arctica (Limacina), 498.
arctica (Saxicava), 596.
arenaria (Mya), 594.
arenaria (Ocypoda), 399.
arenarius (Clitellio), 310.
arenarius ( Haustorius) ,

368.

arenata (Caudina), 650.
arena ta (Molgula), 665.
Arenicola, 299.
arenicola (Asterias), 631.
arenicola (Cythereis), 356.
arenicola (Lycosa), 433.
Arenicolidae, 299.
Argas, 445.
Argasidae, 445.
argentea (Thuiaria), 107.
Argiope, 425.
argo (Argonauta), 612.
Argonauta, 612.
Argonautidae, 612.
Argulidae, 351.
Argulus, 352.
argus (Palinurus), 392.
Argyrodes, 421.
Aricia, 292.
Ariciidae, 292.
Ariolimax, 528.
Arion, 527.
Arionidae, 527.
Arm comb, 636.
Armadillididae, 380.
Armadillidium, 380.
armata (Funiculina), 138.
armata (Trachelomonas),

32.

armifera (Bifidaria), 516.
armigera (Dalyellia), 162.
armigera (Segmentina),

513.

Arrhenurus, 452.
Artemia, 331.
Arthrobranchs, 384.
Arthropoda, 323.

Arthrostraca, 364.
arthusa (Plumatella), 263.
Articulamentum, 484.
Articulata, 3, 4, 326.
articulata (Opercularia),

67.
articulatus (Astropecten),

626.

Ascaridae, 224.
Ascaris, 224.
Ascidia, 667.
Ascidiacea, 663.
Ascidiae compositae, 668.
Ascidiae luciae, 671.
Ascidiae simplices, 664.
Ascidiidae, 667.
Ascon type of sponge, 72.
Ascortis, 76.
Asellidae, 377.
Asellus, 377.
asellus (Oniscus), 379.
asensoriatum

(Stichostemma), 212.
asperata (Misumena), 428.
aspersa (Helix), 519.
Aspidisca, 64.
Aspidobothridae, 178.
Aspidobranchiata, 529.
Aspidocotylea, 178.
Aspidogaster, 179.
Asplanchna, 236.
Asplanchnidae, 236.
Asplanchnopus, 237.
Astacidae, 390.
Astacidea, 389.
Astacus, 390.
Astarte, 577.
Astartidae, 577.
Astasia, 33.
Astasiidae, 32.
AsteracantJiion, 631.
Asterias, 631.
asterias (Isocrinus), 621.
Asteridae, 631.
Asterina, 629.
Asterinidae, 629.
asteriscus (Pyramldula),

522.

Asteroidea. 623.
Asterophora, 45.
Asteropidae, 628.
Astigmatea, 661.
Astraeidae, 148.
Astrangia, 148.
astreoides (Porites), 147.
Astropecten, 626.
Astrophytidae, 638.
Astyris, 557.
Asymmetron, 673.
Atax, 451.
Atlanta, 552.
Atlantic palolo worm, 290.

708

INDEX

atlanticum (Pyrosoma),

671.

Atlantidae, 552.
Atoke, 283.
atra (Ascidia) , 667.
atrica (Zilla), 426.
atropos (Moira), 645.
Attidae, 434.
Attus, 434.

audax (Phidippus), 435.
audebarti (Glottidia), 267.
audonini (Pachylomerus),

416.

Aulactinia, 143.
aurantia (Argiope), 425.
aurantiaca ( Parapolia ) ,

207.
aurantiacus (Balanoglos-

sus), 654.

aurata (Micaria), 430.
Aurelia, 130.

aurelia (Paramecium), 56.
aureus (Volvox), 39.
Auricles, in Ctenophora,

152 ; in Planaria, 165 ; in

Rotifera, 237.

auricula (Haliclystus), 127.
Auricularia, 614, 647.
auricularia (Lymnaea), 510.
Auriculidae, 508.
auriformis (Polygyra), 521.
aurita (Aurelia), 131.
Autolytus, 287.
Autozooids, 137.
autumnalis (Erigone), 423.
avara (Columbella), 557.
avara (Succinea), 519.
Aviculariidae, 416.
Avicularium, 249.
Aviculidae, 573.
avida (Lycosa), 433.
Axial organ, 617.
Axial sinus, 617.
Azygia, 185.
Azygobranchiata, 532.

BABESIA, 47.

bachei (Nemopsis), 98.

bachei (Pleurobrachia),

152.

bairdi (Octopus), 613.
bakeri (Brachionus), 240.
Balanidae, 361.
Balanoglossida, 653.
Balanoglossus, 654.
balanoides (Balanus), 361.
Balantidium, 59.
Balanus, 361.

balbianii (Spirocheta), 26.
baltica (Idothea), 376.
baltica (Macoma), 598.
bancrofti (Filaria), 219.

banksi (Onychoteuthis),

611.
barbadensis (Fissurella),

531.

Barnacle, 360.
bartoni (Cambarus), 391.
ba»trami (Ommatrephes),

610.

Basals, 619.
Basket fish, 638.
Basommatophora, 507.
Bdella, 453.
Bdellidae, 453.
Bdellodrilus, 306.
Bdelloida, 234.
Bdellonemertea, 213.
Bdelloura, 168.
Bdellouridae, 167.
Beach fleas, 366.
Beef tapeworm, 200.
Beetle mites, 442.
Bela, 562.
Belemnitidae, 607.
benedeni (Tubifex), 310.
benneti (Amaurobius), 418.
Beroe, 154.
Beroidae, 154.
beroidea (Tintinnopsis),60.
Bertia, 198.
berfjlinus (Asteracanthion) ,

631.
beumeri (Mesenchytraeus),

308.

bicarinata (Valvata), 545.
bicarinatus ( Planorbis ) ,

512.

Bicellaria, 253.
Bicellariidae, 253.
Bicidium, 142.
bicolor (Lineus), 208.
bicophora (Clytia), 114.
Ucornis (Rattulus), 241.
bicuspidatus (Cyclops), 346.
bidentata ( Ophiacantha ) ,

637.

bifaria (Oxytricha), 63.
biflda (Doris), 502.
Bifidaria, 516.
bigemina (Babesia), 47.
bilamellata ( Onchidoris ) ,

502.
bilimbosum (Cochliopo-

dium), 18.

Mmaculata (Hahnia), 431.
bimaculatus (Tetranychus),

455.
biminiensis (Ptychodera),

654.

Biomyxa, 19.
Bipaliidae, 168.
bipartita (Diphyes), 125.
Bipectinate gill, 529.

bipes (Nebalia), 364.
Bipinnaria, 614, 625.
Bird mites, 440, 444.
Bird spiders, 416.
Birgus latro, 393.
biseriatum (Chelifer), 409.
bisuturalis (Odostomia),

554.

Bittium, 546.
Bivalvia, 481, 567.
Black abalone, 532.
Black corals, 139.
Black sand shell, 580.
Bladder worms, 156, 191.
Blastostyle, 104.
blattarum (Gregarina), 44.
Blepharisma, 58.
Blood clams, 571.
Blood worms, 296.
Blue crab, 398.
Blue-foot, 584.
Bodo, 29.
Bodonidae, 29.
Bolina, 153.
Bolinopsidae, 153.
Bolinopsis, 153.
Boltenia, 667.
bombi (Sphserularia), 217.
Book scorpion, 409.
Boophilus, 446.
Bopyridae, 381.
Bopyroides, 381.
borealis (Cancer), 396.
borealis (Cerianthus), 141.
borealis (Pennatula), 137.
borealis (Solemya), 569.
borealis (Spirorbis), 302.
borealis Steatoda), 421.
borealis ( Venericardia ) ,

577.

boreas (Crangon), 386.
boreus (Vejovis), 405.
Bosmina, 336.
Bosminidae, 336.
bostoniensis (Flabellina),

504.

Bostrichobranchus, 665.
Bothriocephaloidea, 193.
Bothriocephalus, 195.
Bothriocephalus, 194.
Bothrioneurum, 311.
Bothrium, 189.
Botryllidae, 668.
Botrylloides, 669.
Botryllus, 669.
botryoides ( Leucosolenia) ,

75.

botrytis (Codonosiga), 29.
Bougainvillia, 97.
Bougainvilliidae, 96.
Bourgueticrinidae, 621.
bovis (Demodex), 439.

INDEX

709

bovis (Margaropus), 446.
Bowerbankia, 260.
Brachials, 619.
brachiata (Moina), 335.
Brachiolaria, 625.
Brachionidae, 239.
Brachionus, 240.
brachionus (Notops), 237.
Brachiopoda, 264.
Brachyura, 394.
brachyura (Daphnella) , 334.
Brain coral, 149.
Branchellion, 318.
branchlalis (Lernsea), 351.
branchiarum

(Anoplophrya), 57.
Branchinecta, 331.
Branchiobdella, 305.
Branchiocerianthus, 91.
Branchiocerianthus

imperator, 90.
Branchiopoda, 329.
Branchiostoma, 673.
Branchiostomidae, 673.
Branchipodidae, 330.
Branchipus, 330.
Branchiura, 351.
brandaris (Murex), 555.
brasiliensis (Peneus), 388.
brevicauda ( Heterakis ) ,

225.

brevipes (Rhabdostyla), 66.
brevis (Enoplus), 216.
brevispina ( Ophioderma) ,

636.
brevispinosus ( Cyclops ) ,

346.

briareus (Thyone), 649.
Brisingidae, 633.
Brit, 340.
Brittle stars, 633.
Brood sac, 333.
brooksii ( Balanoglossus) ,

654.

Brown body, 249.
Brown hydra, 92.
brucei (Trypanosoma), 30.
brunnea (Amphitrite), 295.
brunnea ( Pleurobrachia ) ,

152.

Bryobia, 455.
Bryozoa, 245.
Buccal plate, 634.
Buccinidae, 558.
Buccinum, 558.
Bucephalidae, 180.
Bucephalus, 180.
bucera (Nephthys), 289.
Bugula, 254.
Bulb mite, 442.
bulbifer

(Rhynchobothrius), 203.

Bulimulidae, 523.

Bulimulus, 523.

bulla (Monostyla), 242.

bullinum (Lembadion), 56.

Bulloidea, 496.

bulloides (Globigerina), 21.

bumpusi (Epibdella), 174.

Bunodera, 185.

Bunodes, 143.

Bunodidae, 143.

Bursa, in Nematodes, 215 ;

in Ophiuroidea, 633.
Bursaria, 59.
bursaria (Paramecium),

56.

Bursariidae, 58.
Busycon, 559.
Butterfly squid, 609.
Byssus, 565.
Bythinia, 541.

CABEREA, 253.
caboti (Salpa), 662.
Cacospongia, 85.
Caddo, 411.

caeca (Chiridotea), 376.
caeca (Micrura), 208.
Caecidotea, 377.
caespitosum

(Cephalothamnium), 28.
Calamaries, 609.
Calamistrum, 414.
Calanidae, 340.
Calanus, 340.

calcarata (Laodicea), 117.
Calcarea, 75.
California shrimp, 386.
calif ornica (Aplysia), 499
calif ornica ( Nuttallina ) ,

488.
calif ornica ( Pleodorina ) ,

38.
calif ornica ( Pomatiopsis ) ,

543.

californica (Trivia), 550.
californicus (Astropecten),

626.

californicus (Conus), 561.
californicus (Laqueus),

269.
californiense

(Branchiostoma), 673.
calif orniensis (Helix), 520.
Caligidae, 349.
caliginosus (Helodrilus),

313.

Caligus, 349.
Callianassa, 389.
Callianassidae, 389.
Callidina, 235.
Callinectes, 398.
Calliobothrium, 195.

Calliopiidae, 368.
Calliopius, 369.
Calliostoma, 532.
Callocardia, 591.
Callus (in snail shells),

492.

Calocalanus, 341.
Calycella, 112.
Calyconectae, 124.
Calyptoblastea, 104.
Calyx, in Bryozoa, 246 ; in

Crinoidea, 619.
Cambala, 470.
cambaria (Entocy there),

357.

Cambarus, 390.
cameo (Cassis), 551.
campanula (Melicertum),

117.
campanula (Vorticella),

65.

Campanularia, 110.
Campanulariae, 104.
Campanulariidae, 110.
campanulata ( Floscularia ) ,

233.
campanulatus (Planorbis),

512.

Campeloma, 544.
campestris (Agriolimax),

527.

Campodes, 470.
canadensis (Grantia), 76.
canadensis (Parajulus),

470.
canadensis (Polydesmus),

471.
Canal (in Gastropoda),

529.
canaliculata (Tornatina),

497.
canaliculatum ( Busycon ) ,

559.
canaliculatus

(Chaetogordius), 281.
Cancellaria, 562.
Cancellariidae, 562.
cancellata (Leucosolenia),

75.

cancellata (Venus), 591.
Cancer, 396.
Cancridae, 396.
cancroides (Chelifer), 409.
Candida (Bdelloura), 168.
candidum (Tetrastemma),

212.

Candona, 355.
caninum (Anchylostoma),

223.
caninum (Dipylidium),

199.
canis (Ascaris), 225.

710

INDEX

canis (Sarcoptes), 440.
Canthocamptus, 348.
caperata (Lymnsea), 510.
capillata (Cyanea), 130.
capita ta (Aulactinia), 143.
capitatus (Dendryphantes),

435.

Capitella, 297.
Capitellidae, 297.
Capitelliformia, 297.
Capitulum, 445.
Caprella, 372.
Caprellidae, 372.
Caprellidea, 372.
Capulidae, 538.
caput-serpentis

(Terebratulina), 269.
cara (Cupulita), 124.
Carapace, 326.
Carchesium, 66.
Carcinides, 398.
Carcinonemertes, 209.
carcinophila

(Carcinonemertes), 210.
Carcinus, 398.
Cardiacea, 592.
Cardiidae, 592.
Cardinal teeth, 564.
cardinalis (Bdella), 453.
Cardisoma guanhumi, 394.
Carditidae, 576.
Cardium, 592.
caribbeum

(Branchiostoma), 673.
carica (Busy con), 559.
Caridea, 385.
Carina, 360.
Carinaria, 552.
carinata (Cyathura), 374.
carinata (Hemiclepsis),

319.

carinata (Neomenia), 484.
Carinella, 206.
Carinellidae, 206.
Carinogammarus, 370.
Carinoma, 206.
carioca (Hymenolepis),

200.

carnea (Cynthia), 666.
carnea (Podocoryne), 100.
carneum (Alcyonium), 135.
carolinensis

(Bougainvillia),97.
carolinensis (Lycosa), 433.
carolinensis (Pelomyxa) , 15.
carolinensis ( Philomycus) ,

528.
carolinianus (Centrurus),

406.

carolinus (Vejovis), 405.
carpenter! (Onchidella),

515.

Carterius, 82.

Cartilage (in pelecypods),

564.

Carychium, 508.
Cassididae, 550.
Cassis, 551.

castanea (Astarte), 577.
castaneiformis (Cynthia),

666.
castaneus (Lumbricus),

313.
castaniceps ( Scolopendra) ,

475.

Castianeira, 430.
Castor bean tick, 446.
Castrada, 163.
casus (Stephanochasmus),

185.

Cat tapeworm, 201.
cataracta (Anodonta), 581.
catascopium (Lymnaea),

510.

catenula (Phyllodoce), 286.
Catenulidae, 161.
Cathypna, 241.
Cathypnidae, 241.
cati (Sarcoptes), 440.
Catometopa, 399.
catostomi (Argulus), 352.
Cattle tick, 446.
catula (Elysia), 505.
caudata (Eupleura), 556.
caudata (Platydorina), 38.
caudatum (Paranieciurn),

56.
caudatum (Strombidium),

60.

caudatus (Bodo), 29.
caudatus (Polychoerus),

160.

caudatus (Priapulus), 276.
caudatus (Tmarus), 428.
Caudina, 650.
cavallaria (Vorticella), 65.
cavatica (Epeira), 425.
cavatus (Hyptiotes), 418.
cavicolens (Phlegmacera),

413.

Cavolinia, 498.
cavolini (Tanais), 373.
Cavoliniidae, 498.
celata (Cliona), 80.
Cellaria, 254.
Cellariidae, 254.
Cellepora, 259.
Celleporidae, 259.
Cellulariidae, 253.
Cellulose, 34, 655.
Centipeds, 473.
Central teeth, 480.
Centrechinidae, 642.
Centrechinoida, 642.

Centrechinus, 642.
Centripetal canals, 120.
Centrodorsal, 621.
Centropages, 342.
Centropagidae, 341.
Centropyxis, 18.
Centruridae, 406.
Centrurus, 406.
Cephalic disc, 496.
Cephalic gland, 204.
cephalicus (Geophilus),

474.

Cephalina, 43.
Cephalochorda, 5.
Cephalochordata, 671.
Cephalodiscida, 652.
Cephalogonimus, 186.
Cephalont, 42.
Cephalopoda, 602.
Cephalothamnium, 28.
Cephalothorax, 326, 400.
Cephalotricidae, 206.
Cephalothrix, 206.
Ceraospongiae, 84.
Cerata, 500.
Ceratine, 133.
Ceratinella, 423.
Ceratium, 40.
ceratophylli (Limnias),

234.

Cercaria, 180.
Cercomonadidae, 27.
Cercomonas, 27.
Cerebral organ, 204.
Cerebral tube, 274.
Cerebratulus, 208.
Ceriantheae, 140.
Cerianthus, 140.
Ceriodaphnia, 335.
Cerithiidae, 545.
Cerithiopsis, 546.
cernua (Pedicellina), 248.
cervi (Paramphistomum),

182.
cervicornis (Acropora),

146.

Cestida, 153.
Cestodaria, 192.
Cestodes, 189.
Cestodes (sensu stricto),

192.

Cestum, 153.
Chsetoderma, 484.
Chsetodermatina, 484.
Chaetogaster, 309.
Chsetognatha, 271.
Chaetogordius, 281.
Chsetonotidae, 243.
Chaetonotus, 243.
chsetophora

(Acanthocystls), 23.
Chaetopleura, 487.

INDEX

711

Chaetopoda, 281.
Chaetopteridae, 293.
Chaetopterus, 293.
Chalarathoracida, 23.
Chalina, 82.
Chalinidae, 82.
charon (Euplotes), 63.
Charybdeidae, 129.
Cheese mite, 442.
Chela, 363.
Chelanops, 410.
chelata (Euratea), 252.
Chelate appendage, 363.
Chelicerae, 401, 413.
Chelifer, 409.
chelif er ( Harpacticus) ,

348.

Cheliferidae, 409.
Chelipeds, 385.
Chelura, 372.
Cheluridae, 372.
Chernes, 410.
Chestnut shell, 577.
Chicken mite, 444.
Childia, 159.
Chiliferidae, 54.
Chilodon, 54.
Chilognatha, 467.
Chilomonas, 36.
Chilopoda, 473.
Chilostomata, 251.
Chiridotea, 376.
Chirocephalus, 330.
Chirodota, 651.
Chiropsalmus, 129.
Chiton, 489.
Chitons, 484.
Chlamydodontidae, 54.
Chlamydomonadidae, 36.
Chlamydomonadina, 36.
Chlamydomonas, 36.
Chlamydophorida, 23.
Chlorhaemidae, 299.
chlorotica (Elysia), 505.
chlorotica (Teredo), 599.
chloroticus (Helodrilus),

313.

Choanocytes, 72.
Choanoflagellida, 28.
Chondracanthidae, 351.
Chondracanthus, 351.
Chondrophora, 608.
Chordata, 652.
Chordodes, 227.
Chordonia, 4, 5.
Chorioptes, 440.
Chromomonadina, 34.
chrysacanthophorus

(Echiurus), 315.
chrysalis (Pleuronema),

56.
Chrysodmus, 558.

Chrysomonadidae, 34.
Chthonius, 410.
Chydorus, 337.
Cidaridae, 642.
Cidaroida, 641.
Cilia, 48.
Ciliata, 50.

ciliata (Bicellaria), 254.
ciliata (Euglypha), 19.
ciliata (Grantia), 76.
ciliata (Microporella),

256.
cincinnatiensis (Amnicola),

542.
cincinnatiensis

(Pomatiopsis), 543.
cincinnatus (Thelepus),

296.

Cinclides, 133.
cinctum (Mesodinium), 52.
cinerea (Epeira), 425.
cinerea (Trochosa), 433.
cinereus (Urosalpin x), 556.
cinereum (Phalangium),

413.

Ciona, 667.
Circinaria, 523.
Circinariidae, 523.
Cirolana, 374.
Cirolanidae, 374.
Cirratulidae, 294.
Cirratulus, 294.
cirratus (Cirratulus), 294.
Cirripathes, 139.
Cirripedia, 358.
Cirrus, 277, 619.
Cittotaenia, 198.
Cladocarpus, 110.
Cladocera, 332.
Clam worms, 288.
claparedianus (Limnodri-

lus), 311.

clarki (Gonothyrea), 112.
clarum (Distoma), 667.
clathrata (Luidia), 626.
Clathrulina, 23.
clausa (Natica), 538.
Clava, 95.

clavaria (Porites), 146.
Clavelina, 668.
Clavelinidae, 668.
Clavidae, 94.
Clepsine, 318.
Clepsine plana, 318.
Clidiophora, 600.
Clinostomum, 187.
Cliona, 80.
Clione, 499.
Clionidae, 80, 499.
Clitellio, 310.
Clitellio iroratus, 310.
Clitellum, 303, 316.

Clover mite, 455.
Clubiona, 429.
Clubionidae, 429.
Clymenella, 299.
clymenellae (Monocystis),

46.

Clypeaster, 644.
Clypeastridae, 644.
Clypeastroida, 644.
Clytia, 114.
Cnemidocoptes, 440.
Cnidae, 89.
Cnidaria, 86.
Cnidoblast, 86.
Cnidocil, 86.
coarctatus (Hyas),395.
Cob-webs, 415.
Coccidiida, 4J8.
Coccidium, 46.
coccineum (Tristoma), 174.
cochlearis, (Anuraea), 239.
Cochlicopa, 517.
Cochlicopidae, 517.
Cochliopodium, 18.
Cochlodesma, 601.
Cockle, 592.
Cocoon, 303, 316.
Codoneca, 27.
Codonecidae, 27.
Codonocladium, 29.
Codonosiga, 29.
Cffilata, 160.
Cffilenterata, 4, 70.
Coelomata, 4.
Coenenchym, 134.
Coenurus cerebralis, 202.
ccenurus (Tcenia), 2O2.
coeruleus (Stentor), 59.
Coffee-bean shells, 550.
Colacium, 32.
coleoptorum (Gamasus),

444.

Coleps, 52.

coli (Balantidium), 59.
coli (Entamoeba), 16.
Collar (mollusks),492.
Collar cells, 72.
Collar flagellates, 28.
Collencytes, 73.
coloradensis (Branchi-

necta),331.
Colpidium, 55.
Colpoda, 55.

colpoda (Colpidium), 55.
columbae (Megninia), 441.
Columbella, 557.
Columbellidae, 557.
columbianus (Ariolimax),

528.
Columella (of snail shell),

492.
columella (Lymnaea), 509.

712

INDEX

Coluridae, 242.

colurus (Monura), 242.

Comactinia, 623.

Comasteridae, 622.

Comatula, 622.

Combs, in ctenophores, 150 ;

in scorpions, 405.
Commercial sponges, 84.
commissuralis (Obelia),

113.

Common star, 631.
communis (Asellus), 377.
communis (Chorioptes),

440.
communis (Diplocardia),

311.

communis (Lycosa), 433.
compacta (Suberites), 79.
complanata (Alasmidonta),

582.
complanata (Glossiphonia),

318.

complanatus (Unlo),583.
Complementary male (in

Cirripedia) , 358.
Compound eye, 324.
compressa (Ampelisca),

368.
compressum (Gleno-

dinium),41.
compressum (Pisidium),

587.

concava (Circinaria), 523.
concava (Koenikea), 452.
concentrica (Neoliodes),

443.

concharum (Cirolana), 374.
concharum (Polydora),

293.
conchicola (Aspido-

gaster), 179.
Conchifera, 567.
Conchoderma, 361.
Conchcecia, 358.
Conchs, 548, 559.
concinna (Forella), 258.
Condylostoma, 59.
confoederata (Salpa),662.
Congeria, 584.
conica (Creseis), 499.
conica (Cyclosa), 425.
conicum (Paramphisto-

mum), 182.
Conidae, 561.
Conjugation, 12.
conklini (Dinophilus), 280.
Conochilus, 234.
conradi (Thracia), 601.
conspcrsa (Graphosa), 419.
constellatum (Araarou-

cium),670.
constricta (Difflugia), 17.

contectoides (Vivipara),

544.

contorta (Astasia), 33.
contracta (Corbula), 595.
Contractile vacuole, 12. *
Conus, 561.
convallaria (Vorticella),

65.

convexa (Callocardia), 591.
convexa (Crepidula), 539.
convexus (Cylisticus), 379.
Convolutidae, 159.
Copepoda, 339.
Copeus, 238.
cophocerca (Oikopleura)

659.

Corallidae, 135.
Corallium, 135.
Corals, 132.
Coras, 431.
Corbula, 595.
Cordylophora, 95.
coriacea (Fontaria), 472.
Cornulariella, 134.
Cornulariidae, 134.
cornutus (Autolytus), 287.
cornutus (Chondra-

canthus),351.
Corona, 230, 639.
corona (Difflugia), 18.
coronata (Doto),504.
coronata (Ephelota), 68.
Coronatae, 127.
coronatum (Polystoma),

176.

Coronula, 362.
Coronulidae, 362.
Corophiidae, 371.
Corophium, 371.
corticaria (Bifidaria), 516.
Corymorpha, 101.
Corymorphidae, 101.
Corynidae, 95.
Coryphella, 504.
costata (Alasmidonta),

582.

costata (Pholas),597.
costata (Siliqua),595.
costata (Vallonia),518.
Cothurnia, 67.
Cotylaspis, 179.
Cotylea, 171.
Cotylogaster, 178.
couthouyi (Tubularia), 103.
Cowries, 549.
Coxal plate, 448.
Crab spiders, 427.
Crabs, 394.

'cracherodi (Haliotis), 532..
Cranchiidae, 612.
Crangon, 386.
Crangonidae, 386.

Crania, 268.
Craniidae, 268.
Craspedacusta, 119.
Craspedomonadidae, 28.
Craspedsomidae, 470.
Craspedote medusa, 88.
crassa (Eunicea), 137.
Crassatellites, 577.
Crassatellitidae, 577.
crassicaudum (Tricho-

soma), 221.

crassicolis (Taenia), 201.
crassicornis (Tealia), 143.
crassipalpis (Clubiona),

429.

Crassobothrium, 196.
craticula ( Membranipora ) ,

256.
cratoparis (Asterophora),

45.

Crayfish, 390.
crenatus (Balanus), 362.
Crenella, 572.
Crepidula, 539.
Creseis, 499.
Cribellum, 414.
Cribrella, 629.
Cribriform organs, 627.
Cribrilina, 256.
Cribrilinidae, 256.
Crinoidea, 619.
Crisia, 250.
Crisiidae, 250.
crispata (Zirphsea), 598.
crispatus (Ctenodiscus),

027.

cristata (Arenicola), 299.
Cristatella, 264.
Cristatellidae, 264.
cristallinus (Lophopus),

263.

crocata (Castianeira), 430.
crocea (Tubularia), 104.
Crossobothrium, 196.
crotali (Porocephalus), 457.
Crucibulum, 539.
Crustacea, 326.
Cryptochiton, 489.
Cryptodon, 585.
Cryptoglena, 32.
Cryptomonadidae, 35.
Cryptomonas, 36.
Cryptophialus, 358.
Cryptops, 475.
crystallina (Cothurnia), 67.
crystallina (Sida),333.
Crystalline rod, 566.
crystallinus (Oecistes), 234.
Ctenidia, 480, 565.
Ctenobranchiata, 534.
Ctenodiscus, 627.
Ctenophora, 150.

INDEX

713

Ctenostomata, 259.
cubanum (Myzostoma),

322.

Cubomedusae, 128.
Cuculanus, 224.
cucullulus (Chilodon), 54.
cucullus (Colpoda), 55.
Cucumeria, 649.
Cucumeriidae, 649.
cucumcrinum (Dipylidium),

199.
cucumeris (Tetranychus),

455.

cucumis (Beroe), 154.
Cumacea, 384.
cumanense (Siphonosoma),

275.

Cumingia, 589.
cuinmingi (Ibla), 360.
cuniculi (Eimeria), 46.
Cunina, 121.
Cunoctantha, 121.
Cup-and-saucer limpit, 539.
cuprea (Diopatra), 290.
cupressina (Thuiaria), 108.
Cupulita, 124.
curticorne (Extinosoma),

348.

Curvlpes, 451.
Cuspidaria, 602.
Cuspidariidae, 601.
Cuttle bone, 608.
Cuttle fish, 608.
Cuvier's organs, 646.
Cyanea, 130.
Cyaneldae, 130.
cyanella (Pelagia), 129.
Cyathocephalinae, 194.
Cyathocephalus, 194.
Cyathomonas, 36.
Cyathura, 374.
Cyclas, 586.
Cyclocoelidae, 181.
Cyclocoelum, 181.
Cyclonietopa, 396.
Cyclophyllidea, 197.
Cyclopidae, 345.
Cyclops, 345.
Cyclosa, 425.
Cyclosalpa, 662.
Cyclostomata, 250.
clyclostomus (Urceolus), 33.
Cydippida, 152.
Cyllchnella, 497.
cylindricum (Corophlum),

371.

Cylisticus, 379.
Cymothoidae, 375.
Cynthia, 666.
Cynthiidae, 666.
Cyphoderia, 19.
Cyphonantes, 260.

Cypraea, 549.
Cyprseidae, 549.
Cypria, 355.
Cypridae, 353.
Cypridinldae, 357.
Cypridopsis, 355.
Cyprina, 578.
Cyprinidae, 578.
Cypris, 354.
Cyrenidae, 586.
Cyrtoceras, 606.
Cyrtodaria, 596.
Cysticercoid, 191.
Cysticercus, 191.
Cysticercus bovis, 200.
Cysticercus cellulosae, 201.
Cysticercus fasciolaris, 202.
Cysticercus pisiformis, 201.
Cysticercus tenuicollis, 201.
Cystici, 156.
Cystobranchus, 318.
Cystoflagellidia, 41.
Cystonectae, 123.
Cythereis, 356.
Cytheridae, 355.
Cyzicus, 332.

DACTYLOMETRA, 130.
Dactylophoridae, 44.
Dactylosphffirium, 16.
Dactylozooids, 93, 122.
Daddy longlegs, 410.
Daisy brittle star, 636.
Dalyellia, 162.
Dalyelliidae, 162.
danae (Astrangia), 148.
Daphnella, 334.
Daphnia, 334.
Daphnidae, 334.
Dart sac, 519.
Dasydytes, 244.
Datames, 408.
Davainea, 200.
Davaineidae, 200.
davenport! (Loxosoma),

247.
davenporti (Microstomum),

162.
davidoffi (Tintinnopsis),

60.

Dead men's fingers, 82.
dealbatus (Bulimulus), 523.
debilis (Diaphana), 497.
Decapoda (Crustacea), 384.
Decapoda (Mollusca), 607.
decemcostata (Neptunea),

559.

decisum (Campeloma), 544.
decora (Macrobdella), 320.
deflectus (Planorbis), 513.
delphinodonta (Nucula),

568.

demissus (Modiolus), 572.
democratica (Salpa),662.
Demodex, 439.
Demodicidae, 439.
Demospongiae, 78.
Dendroclavidae, 102.
Dendroco3lum, 166.
Dendronotidae, 500.
Dendronotus, 501.
Dendrosoma, 69.
Dendrosomidae, 69.
Dendryphantes, 435.
dentale (Dentalium), 491.
Dentaliidae, 491.
Dentalium, 491.
Dentary apparatus, 640.
dentata (Antedon), 622.
dentata (Arcella), 18.
dentata (Hyalella), 368.
denticulatum (Doliolum),

661.
denticulatum (Penta-

stomum), 457.
Denticulus elephantis, 490.
depressa (Ampullaria), 545.
depressus (Panopeus), 397.
derhami (Tegenaria), 431.
Dermacentor, 447.
Dermaleichidae, 440.
Dermaleichus, 441.
Dermanyssus, 444.
Dermasterias, 628.
Dero, 309.
descripta (Castianeira),

430.

deses (Euglena), 32.
Desmothoracida, 23.
Desor's larva, 205.
despectus (Tergipes), 505.
despiciens (Diplodontus),

450.

Deutomerite, 43.
Devil-fish, 602, 613.
Diadema, 642.
diadema (Coronula), 362.
diademata (Tiaropsis), 114.
dianthus (Hydroides), 302.
Diaphana, 497.
Diaptomus, 343.
Diastylidae, 384.
Diastylis, 384.
Dibothriocephalus, 194.
Dibothrium, 195.
Dibranchiata, 606.
dibranchiata (Glycera),

291.

Dichelestiidae, 350.
Dichelestium, 350.
dichotoina (Amathia), 261.
dichotoma (Obelia),113.
dichotoma (Plexaurella),

137.

714

INDEX

Diclidophora, 176.
Dictyna, 418.
Dictynidae, 418.
Dlctyocaulus, 222.
Didemnum, 671.
Didemnidae, 670.
Didinium, 52.

differens (Theridion), 422.
Difflugia, 17.
diffusa (Oculina),148.
diffusa (Plumatella), 263.
Digenea, 179.
Digenetic trematodes, 172.
digitale (Peridinium), 40.
digitalis (Aglantha), 120.
digitatum (Cochliopodium),

18.

dilatata (Euchlanis), 242.
Dileptus, 53.
diminuta (Hymenolepis),

200.

Dina, 321.
Diniferida, 40.
Dinobryon, 34.
Dinocharidae, 240.
Dinoflagellidia, 39.
Dinophilidae, 280.
Dinophilus, 280.
Dinophysidae, 41.
Dioctophyme, 222.
diogenes (Cambarus), 392.
Diopatra, 290.
Diophrys, 63.
Diotocardia, 529.
Diphasia, 107.
Diphyes, 125.
Diphyidae, 125.
Diphyllobothriidae, 193.
Diphyllobothriinae, 194.
Diphyllobothrium, 194.
Diplocardia, 311.
Diplocentrus, 405.
Diplodiscus, 182.
Diplodontus, 450.
Diplogaster, 217.
Diplophrys, 21.
Diplopoda, 467.
Diplostomum, 188.
Dipneumones, 416.
Dipurena, 96.
Dipylidiidae, 199.
Dipylidium, 199.
Directives, 138.
directus (Ensis),595.
Discocotyle, 176.
Discodrillidae, 305.
discolor (Holophrya), 51.
Disconectae, 123.
Discoporella, 251.
discors (Modiolaria), 572.
discus (Dosinia), 591.
dislocata (Terebra), 561.

dispar (Eudendrium), 99.
Dissepiment, 277.
distichus (Pterodrilus),

306.
Distoma :

in Trematodes, 172.

in Tunicata, 669.
Distomata, 182.
Distomida, 182.
Distomidae, 669.
Ditremata, 514.
Diurella, 241.
divaricata (Porites), 147.
divergens (Peridinium), 40.
diversa (^Eolidia), 503.
diversicolor (Aphanos-

toma) , 159.
divisa (Acineta), 68.
divisus (Tagelus), 596.
Docoglossa, 530.
dodgei (Dalyellia),162.
Dog tick, 447.
Dolichoglossus, 654.
Doliidae, 550.
Doliocystidae, 45.
Doliocystis, 45.
Doliolum, 661.
Dolium, 550.
Dolomedes, 432.
domiciliorum (Epeira),

426.

Donacidae, 589.
Donax, 589.
Dorididae, 502.
Doridioidea, 501.
Doris, 502.
Dorsal lamina, 656.
dorsalis (Oerstedia), 213.
dorsalis (Pallifera), 528.
dortocephala ( Planaria ) ,

166.

Dorylaimus, 216.
Dosinia, 591.
Doto, 504.
Dotonidae, 504.
draco (Pterosagitta), 272.
Drassidae, 419.
Drassus, 419.
Dreisseniidae, 584.
drobachiensis ( Strongylo-

centrotus),644.
dubia (Libinia), 395.
dujardini (Echinoderes),

244.

dujardini (Halisarca), 86.
duodecimalis (Eucheilota),

115.
duodenale (Anchylostoma),

223.

duplicata (Natica), 537.
duplicatus (Astropecten),

626.

duttoni (Tibellus),429.
Dwarf tapeworm, 200.
Dysdera, 419.
Dysderidae, 419.
dysentariae (Entamoeba),
16.

EAR SHELLS, 531.
Earthworms, 312.
Ebo, 428.

eburnea (Crisia), 250.
eburneus (Balanus), 362.
Ecardinea, 267.
Echeneibothrium, 197.
Echinarachnius, 644.
Echinaster, 629.
Echinasteridae, 629.
echinata (Cynthia), 667.
echinata (Hydractinia),

100.

echinata (Thenea),78.
echinatum (Echinostoma),

184.

Echinidae, 643.
Echiniscus, 458.
Echinocephalus, 44.
Echinococcus, 202.
Echinococcus polymorphus,

202.

echinococcus (Taenia), 202.
Echinoderes, 244.
Echinoderidae, 244.
Echinodermata, 614. .
Echinoidea, 638.
Echinomera, 44.
Echinorhynchidae, 229.
Echinorhynchus, 229.
Echinostoma, 184.
Echinothuriidae, 642.
Echiurida, 314.
Echiurus, 315.
Ectinosoma, 348.
Ectocyst, 245.
Ectopleura, 102.
Ectoprocta, 248.
Ectosarc, 11.
edax (Cyclops), 346.
edentulus (Strophitus),

581.

Edible crab, 398.
Edible mussel, 571.
Edible snail, 519.
Edotea, 377.
edulis (Mytilus),571.
ed ward si (Lepeoph-

theirus), 350.
edwardsi (Pontocypris),

355.
edwardsi (Pseudocyther-

etta),356.

edwardsi (Scyllsea), 500.
Edwardsia, 140.

INDEX

715

Edwardsiae, 139.
Edwardsiella, 140.
Eelworm, 224.
Egg sacs, 330, 339.
ehrenbe^gi (Mesostoma),

163.
ehrenbergi (Paludlcella),

261.
eichhorni (Actinosphae-

rium),23.
eichhorni (Stephanoceras),

233.

Eimeria, 46.
eiseni (Peripatus), 463.
eiseni (Sparganophilus),

312.

Eisenia, 313.
Eiseniella, 314.
Elasmopus, 370.
electus (Dermacentor),

447.

elegans (Callidina), 235.
elegans (Clathrulina), 23.
elegans (Cuculanus), 224.
elegans (Edwardsla), 140.
elegans (Eudorina), 38.
elegans (Fungia), 150.
elegans (Glossiphonia),

318.
elegans (Gyrodactylus),

177.
elegans (Raphidiophrya),

23.

elegans (Sagitta), 272.
elegans (Tetrastemma),

212.

elegans (Turbonilla), 554.
elephantis (Denticulus),

490.
elevatum (Pleurocera),

547.

elinguis (Nais), 308.
ellipticus (Renifer), 185.
ellipticus (Stylochus),170.
ellisi (Caberea),253.
Eloactis, 142.
elodes (Lymnaea), 510.
elongata (Maldane), 298.
elongata (Monas),28.
elongata (Physa), 512.
Elysia, 505.
Elysiidae, 505.
Elysioidea, 504.
Elytra, 284.
emarginata (Galumna),

443.

emarginata (Libinia), 395.
emersoni (Amicula), 489.
emissarius ( Haplotaxis ) ,

306.

Emplectonema, 209.
Emplectonematidae, 209.

empusa (Pallene), 460.
empusa (Squilla), 384.
Enchelinidae, 50, 51.
Enchelys, 51.
Enchytraeidae, 306.
Enchytraeus, 307.
Enchytrceus triventralo-

pectinatus, 309.
Encope, 645.
Encystment, 12.
endeca (Solaster), 630.
Endltes, 414.
Endodontidae, 522.
Endopodite, 326.
Endostyle, 655.
Enoplidae, 216.
Enoplobranchus, 296.
Enoplus, 216.
Ensis, 595.

entale (Dentalium), 491.
Entamceba, 16.
Enteropneusta, 652.
Entoconcha, 494.
Entocythere, 357.
Entomostraca, 328.
Entoprocta, 246.
Entosarc, 12.
Entosiphon, 34.
Entozoa, 156.
entozoon (Balantidium),

59.

Eoplacophora, 486.
Epeira, 425.
Epeiridae, 424.
Ephelota, 68.
Ephippium, 333.
ephippium (Anomia), 570.
Ephydatia, 81.
Ephyra, 125.
Ephyropsidae, 128.
Epiactis, 143.
Epibdella, 174.
Epiblemum, 435.
Epicardium, 670.
Epicllntes, 61.
Eplgynum, 415.
Epimerite, 43.
Epiphragm, 506.
Epipodlum, 479.
Epischura, 343.
Epistome, in Bryozoa, 246,

262 ; In Phoronldea, 270 ;

in Acarina, 436.
Epistylis, 66.
Epitoke, 283.
Eplzoanthus, 141.
equina (Hippospongia), 85.
equinus (Strongylus), 224.
equorum (Ascaris), 225.
erecta (Pottsiella), 262.
eremita (Phascolosoma),

275.

Eremobates, 408.
Ergasidae, 348.
Ergasilus, 349.
Erichsonella, 377.
Erigone, 423.
Erineum, 438.
Eriophyes, 438.
Eriophyidae, 438.
Erycinidae, 585.
erythropygus (Euryurus),

472.

Escharidae, 257.
esculenta (Rhopilema), 131.
esculentus (Tripneustes),

643.

Esperella, 83.
Esperellldae, 83.
Estheria, 332.
Eteone, 286.
Eucheilota, 114.
Euchlanidae, 242.
Euchlanis, 242.
Eucidaris, 642.
Euconulus, 525.
Eucopepoda, 340.
Eucopidae, 112.
Eucratea, 252.
Eucrateidae, 252.
Eudendriidae, 98.
Eudendrium, 98.
Eudorina, 38.
Eudoxia, 125.
Euglandina, 524.
Euglena, 31.
Euglenida, 31.
Euglenidae, 31.
Euglypha, 19.
Euglyphidae, 19.
Eugyra, 665.
Eukrohnia, 272.
Eulalia, 286.
Eulamellibranchiata,

575.

Eulima, 553.
Eulimidae, 553.
Eunice, 289.
Eunicea, 136.
Euplectella, 77.
Euplectellidae, 77.
Eupleura, 556.
Euplotes, 63.
Euplotidae, 63.
Euryalae, 638.
Euryale, 635.
Eurycercus, 336.
Eurypanopeus, 397.
Eurypauropodidae, 467.
Eurypauropus, 467.
Eurytemora, 342.
Euryurus, 472.
Euspongla, 84.
Eustrongylus, 222.

716

INDEX

Euthyneura, 494.
Euthyneurous gastropods,

493.

Eutima, 115.
Eutreptia, 32.
Evadne, 338.

evansi (Trypanosoma), 30.
exacutus (Planorbis), 513.
exanthema (Cyprsea), 550.
excisus (Nothrus),443.
exigua (Liriope), 120.
exiguum (Carychium), 508.
eximius (Polycirrus), 296.
Exopodite, 326.
exotica (Ligyda), 380.
expansa (Moniezia), 199.
exsculpta (Cypria), 355.
extendens (Eylais), 449.
extensa (Tetragnatha),

427.

Exumbrella, 88.
Exuviella, 39.
Eylainae, 448.
Eylais, 448.

FABRICIA, 301.
fabricii (Psolus), 650.
Fairy shrimp, 330.
falcata (Hydrallmania),

108.
falciparum (Plasmodium),

47.

fallax (Diphasia),107.
fallax (Pupoides),516.
ifamiliaris (Marpissa), 435.
fareta (Urotricha), 51.
farinacea (Halcampa), 142.
farinae (Tyroglyhus), 442.
fasciatus (Gammarus),

370.

fascicularis (Lepas), 360.
fasciculatus (Polyxenus),

473.

Fasciola, 183.
fasciola (Lionotus). 53.
Feather-stars, 619.
ferox (Amaurobius), 418.
ferussacianus (Anodon-

toides),583.

fervida (Herpobdella), 321.
festivus (Murex),555.
flbrexilis (Esperella), 83.
Fiddler crabs, 399.
Filaria, 219.

fllaria (Dictyocaulus), 222.
Filariidae, 219.
Filibranchiata, 570.
filiformis (Erichsonella),

377.
filiformis (Notomastus),

297.
Filistata, 419.

Filistatidae, 419.
Filograna, 302.
filosa (Lucina), 585.
fimbria (Tubulipora), 251.
fimbriata (Ammotrypane),

298.
fimbriata (Gyrocotyle),

192.

fimbriata (Xylotrya), 599.
fimbriatus (Stephanoeeros),

233.

Final host, 180, 191.
Finger shell, 549.
Finger sponge, 82.
finmarchicus (Calanus),

340.

fissiceps ( Cera tinella), 424.
Fissurella, 531.
Fissurellidae, 531.
fistulosa (Cellaria), 254.
flabellaris (Tubulipora),

250.

flabellata (Bugula), 254.
Flabellina, 504.
Flabellum, 147.
flabellum (Gorgonia), 136.
flabellum (Oikopleura),

659.

flaccida (Ophiomyxa), 637.
Flagellata, 24.
Flagellate chambers, 72.
Flagellidia, 25.
flagelliformis (Aplysina),

85.
Flagellum, in crustaceans,

327, 363 ; in gastropods,

519 ; i.n protozoans, 24.
Flame cells, 156.
Flatworms, 156.
fiavicans (Epistylis), 66.
flavicornis (Campodes),

470.

flavidula (Aurelia), 131.
flavidus (Spintharus),421.
flavus (Limax), 526.
flexilis (Cladocarpus), 110.
flexuosa (Campanularia),

111.

Float, 262.

Florida crayfish, 392.
floridana (Holothuria),

649.
floridana (Monocotyle),

175.
floridana (Waldheimia),

269.

floridanus (Conus),562.
Floscularia, 232.
Flosculariidae, 232.
Flukes, 171.
Fluminicola, 542.
Flustra, 255.

Flustrella, 260.
Flustrellidae, 260.
Flustridae, 255.
fluviatilis (Anodonta), 581.
fluviatilis (Ephydatia), 81.
Flying squids, 610.
foetida (Eisenia), 313.
foliacea (Amphilina), 192.
foliacea (Dictyna), 418.
foliacea (Flustra), 255.
foliata (Luidia),627.
folia ta (Epeira),425.
foliatum (Phyllobothrium),

197.

folium (Asterina),629.
folium (Leptoplana), 171.
folliculorum (Demodex),

439.

fontanus (Dolomedes), 432.
Fontaria, 472.
fontariae (Amphoroldes),

45.
fontinalis (Lernffiopoda),

351.

Food vacuole, 12, 49.
Foot (in mollusks), 479.
Foraminifera, 14, 21.
forbesi (Asterias), 631.
Jorbesi (Cyclops), 346.
forceps (Scutigera) , 477.
Forcipulata, 631.
forficatus (Lithobius), 476.
forficula (Furcularia),

238.
formica (Synemosyna),

436.
formidabilis (Eremobates),

408.
formosa (Heteromysis),

383.

formosa (Tima), 115.
fornicata (Crepidula), 539.
forskali (Beroe),154.
fossor (Donax), 589.
fossularis (Stylaria), 309.
fossulata (Unionicola),

451.

fragilis (Ascortis), 76.
fragilis (Janthina), 535.
fragilis (Leucosolenia), 76.
fragilis (Scolopos), 292.
fragilis (Spongilla), 81.
franciscana (Artemia), 331
franciscorum (Crangon),

386.

Fredericella, 262.
Fredericellidae, 262.
Fredericia, 307.
French snail, 519.
Fresh-water clams, 578.
Fresh-water mites, 447.
Fresh-water mussels, 578.

INDEX

717

Fresh-water ollgochsDts,

308.

Fresh-water snails, 506.
Fresh-water sponges, 80.
Fringed tapeworm, 199.
Fritillaria, 559.
frondeum (Theridion), 422.
frondosa (Cucumeria), 649.
Frontal appendages, 330.
Frontal organs, 205.
Frontonia, 54.
fucata (Leodice), 290.
fulgens (Haliotis),532.
Fulgur, 559.

fulgurans (Nerita), 534.
fulgurans (Podocoryne),

100.
fuliginosa (Omphalina),

525.

fulva (Cyanea), 130.
fulva (Linotsenia),474.
fulvus (Euconulus), 525.
funduli (Argulus), 352.
funduli (Piscicola),317.
Fungacea, 149.
Fungia, 150.
Fungiidae, 150.
Funiculina, 138.
Funiculinidae, 138.
Funiculus, 248.
Funnel, 602.
Funnel-web spiders, 430.
Furca, 339, 352.
furcata (Fritillaria), 659.
furcata (Porites), 147.
Furcularia, 238.
ifusca (Glossiphonia), 34.8.
fusca (Hydra), 92.
fusca (Odostomia), 554.
fuscata (Cypris), 354.
fusiformis (Rhizogeton),

95.

fusiformis (Salpa),662.
fusus (Ceratium), 41.

GALBA (Hyperia), 365.
galea (Dolium), 550.
Gall mites, 438.
gallinae (Dermanyssus),

444.

Galumna, 443.
Gamasidae, 443.
Gamasus, 444.
gambiense (Trypanosoma),

30.

Gammaridae, 369.
Gammaridea, 366.
Gammarus, 369.
garden! (Mnemiopsis), 153.
gardineri (Anaperus), 159.
gardineri (Dinophilus),

280.

gasterostei (Schisto-

cephalus), 194.
Gasterostomata, 180.
Oasterostomum, 180.
Gastranella, 588.
Gastrodonta, 526.
Gastropoda, 492.
Gastrotricha, 243.
Gastrovascular space, 86.
Gastrozooid, 93, 122.
gayi (Sertularella), 106.
Gebia, 389.
Gelasimus, 399.
gelatinosa (Obelia), 114.
Gem shell, 591.
Gemellaria, 253.
Gemma, 591.
gemma (Gemma), 591.
Gemmaria, 96.
gemmosa (Gemmaria), 96.
Gemmules of sponges, 73.
geniculata (Obelia), 114.
Genital bursa, 633.
Genital plate, 640.
Geodia, 78.
Geodiidae, 78.
geographica (Hydrachna),

449.

geometrica (Caprella), 372.
Geonemertes, 210.
Geophilidae, 474.
Geophilus, 474.
Geoscolecidae, 312.
Gephyrea, 272.
Geryoniidae, 120.
gesserensis (Lineus), 207.
Giant clam, 589.
Giant scallop, 575.
Giant squids, 610.
gibberosa ( Mango ra), 427.
gibbosus (Unio),583.
gibbus (Tagelus),596.
Gid tapeworm, 202.
gigantea (Gnaphosa), 419.
gigantea (Scolopendra),

475.
giganteus (Mastigoproc-

tus),407.

Glgantorhynchidae, 230.
Gigantorhynchus, 230.
gigas (Dioctophyme), 222.
gigas (Epeira),426.
gigas (Gigantorhynchus),

230.

gigas (Strombus), 548.
gigas (Tridacna), 592.
Girdle (in Chitons), 484.
glaber (Bothrioneurum),

311.

glabrum (Myzostoma), 322.
glandula (Crenella), 573.
Glass sponges, 77.

Glenodinium, 41.

globator (Volvox), 39.

Globigerina, 21.

Globigerinidae, 21.

globosa (Epeira),426.

globulosa (Diffugia), 17.

Glochidium, 679.

Glossiphonia, 318.

Glossiphoniidae, 318.

Glottidia, 267.

Glove-sponge, 84.

Glycera, 291.

Glyceridae, 291.

Gnaphosa, 419.

Gnathobdellida, 319.

Gnathochilarium, 467.

Gnathopod, 365.

Gonangium, 104.

Goniada, 291.

Goniasteridae, 627.

Goniobasis, 547.

Gonionemus, 118.

Gonium, 37.

gonocephala (Planaria),
166.

Gonosome, 90.

Gonotheca, 104.

Gonothyrea, 112.

Gonozooids, 122.

goodei (Flabellum),147.

Goose barnacle, 360.

Gordiacea, 225.

Gordiidae, 227.
gordioides (Haplotaxis),

306.

Gordius, 227.
Gorgodera, 186.
Gorgoderina, 186.
Gorgonacea, 135.
Gorgonia, 136.
Gorgoniidae, 135.
Gorgonocephalus, 638.
gossypina (Hippospongia),

85.

gouldi (Botryllus),669.
gouldi (Cryptodon),585.
gouldi (Limnetis), 332.
gouldi (Pectinaria),297.
gouldi (Phascolosoma),

275.

gouldi (Retusa),497.
gouldiana (Clidiophora),

600.
gracile (Emplectonema),

209.

gracile (Gymnodinium), 41.
gracile (Prosthiostomum),

171.
gracilescens (Bucephalus),

181.

gracilis (Artemia), 331.
gracilis (Bowerbankia), 260.

718

INDEX

gracilis (Capitella), 297.
gracilis (Codoneca), 27.
gracilis (Lampsilis), 580.
gracilis (Phagocata), 167.
gracilis (Podophrya), 68
gracilis (Urnatella) 247.
gracillima (Schizotricha),

110.

graffl (Dendrocoelum), 166.
grande (Diplostomum),

188.

grande (Liobunum), 412.
grande (Stenostomum),

161.

grandinella (Halteria), 60.
grandis (Anodonta), 581.
grandis (Cirratulus), 294.
grandis (Hsemopis), 320.
grandis (Onychodromus),

62.

grandis (Pennatula), 137.
Grantia, 76.
Grantiidae, 76.
granulatus (Scytonotus),

472.
granulosus (Echinococcus),

202.

Graptoliberis, 336.
Grass spider, 431.
Grass sponge, 85.
grata (Rathkea), 98.
gratiae (Scutigerella), 466.
Green abalone, 532.
Green crab, 398.
Green hydra, 92.
Green snail, 533.
Green urchin, 644.
greeni (Cerithiopsis), 546.
Gregarina, 44.
Gregarinida, 42.
Gregarinidae, 43.
Gribble, 375.
grisea (Hydra), 92.
griseus (Prorodon), 51.
groenlandica (Natica), 538.
groenlandica (Phyllodoce),

286.
groenlandica (Scalaria),

535.
groenlandica (Zygodoctyla),

116.
groenlandicus (Serripes),

593.

Gromia, 20.
Gromiidae, 20.
grossa (Malacobdella), 213.
grossipes (Nymphon), 461.
Guinea worm, 220.
Gunda, 167.

gutta (Amphileptus), 53.
Gymnoblastea, 93.
Gymnodinium, 41.

Gymnoglossa, 553.
Gymnolaemata, 249.
gymnota ( Coryphella ) ,

504.

Gynogonidia, 39.
Gyratiricidae, 163.
Gyratrix, 164.
gyrina (Physa), 511.
Gyroceras, 606.
Gyrocotyle, 192.
Gyrodactylidae, 177.
Gyrodactylus, 177.

HADROMERINA, 79.
Hadrurus, 405.
haematobium

(Schistosoma), 187.
Hsemopis, 320.
Haemosporidiida, 46.
Hahnia, 431.
Hair worms, 218, 225.
Halacaridae, 453.
Halacarus, 453.
Halarachne, 437.
Halcampa, 142.
Halcampidae, 142.
balecinum (Halecium),

110.

Halecium, 110.
Haleremita, 92.
Halichondrina, 80.
Haliclystus, 127.
Halicondria, 83.
Halimocyathus, 127.
Haliotidae, 531.
Haliotis, 531.
haliotoidea (Testacella),

524.
haliotoidea, (Velutina),

538.

Halipegus, 186.
Halisarca, 86.
Halisarcidae, 85.
Haller's organ, 445.
Halocynthia, 667.
Halocypridae, 357.
Halocypris, 357.
Halopsis, 116.
Halteria, 60.
Halteriidae, 60.
hamata (Eukrohnia), 272.
Haminea, 497.
hammonis (Vitrea), 525.
Hanleyia, 486.
haplonema (Tamoya), 129.
Haplotaxidae, 306.
Haplotaxis, 306.
Hard-shell clam, 590.
Harmothoe, 285.
Harp shell, 560.
Harpa, 560.
Harpacticidae, 347.

Harpacticus, 348.
harpae (Acroperus), 336.
harpularia (Bela), 562.
Harrimania, 655.
Harrimaniidae, 654.
harvardiensis (Alderia),

505.

Harvest mites, 453.
Harvestmen, 410.
hassalli (Polystoma), 176.
hastata (Aphrodita), 284.
hastatus (Callinectes), 398.
Hatchet-back, 582.
Haustorius, 368.
Hectocotylus, 604.
Jhelgolandicus

(Phonorhynchus), 163.
Helicidae, 519.
Helicina, 534.
helicina (Margarita), 533.
Helicinidae, 534.
Heliodiscus, 523.
heliophila (Stylotella), 84.
Heliozoa, 21.
Helix, 519.
helluo (Lycosa),433.
Helodrilus, 313.
Hemichorda, 5, 653.
Hemichordata, 652.
Hemiclepsis, 319.
hemistoma (Aglaura), 120.
Hemistomum, 188.
Hemiurus, 187.
hemphilli (Pallifera), 528.
hemprichi (^Eolosoma),

305.

Henricia, 629.
hepatica (Fasciola), 183.
herbsti (Panopeus), 397.
Hermaeidae, 504.
hermaphroditus

(Gyratrix), 164.
Hermellidae, 303.
Hermelliformia, 302.
Hermit crabs, 393.
heros (Natica), 537.
heros (Scolopendra), 475.
Herpetomonas, 27.
Herpobdella, 321.
Herpobdellidae, 321.
herricki (Asplanchna), 236.
Hesionidae, 287.
Heterakis, 225.
heterochelis (Alpheus),

388.
heteroclita (Glossiphonia),

319.

Heterocoela, 76.
Heterocotylea, 172.
Heterodera, 217.
Heteromastigda, 29.
Heteromeyenia, 81.

INDEX

719

Heteromonadidae, 27.
Heteromysis, 383.
Heteronemertea, 207.
Heteronereis, 288.
Heteropbrys, 23.
Heteropoda, 551.
heterostropha (Physa),

511.

Heterotrichida, 57.
Hexactinellidae, 77.
Hexactiniae, 141.
hexagonus (Hyroides), 302.
Hexamitus, 31.
hexaptera (Sagitta), 272.
hexaris (Aspidisca), 64.
hibernalis (Filistata), 419.
hincksi (Campanularia),

111.

Hinge (in pelecypods), 564.
Hippa, 393.
Hippasteria, 627.
Hippidae, 393.
Hippolyte, S87.
hippolytes (Bopyroides),

382.

Hipponoe, 643.
Hippospongia, 84.
Hircinia, 85.
hirsuta (Polygyra), 521.
hirsutum (Alcyonidium),

260.

hirsutus (Hadrurus), 405.
hirsutus (Planorbis), 513.
hirtus (Coleps), 52.
hirudinaceus

(Gigantorhynchus), 230.
Hirudinea, 315.
Hirudinidae, 320.
Hirudo, 320.
hirundoides (Eurytemora),

343.

hispida (Echinomera), 44.
hispida (Flustrella), 260.
hispida (Lichenopora), 251.
hispida (Tethya),79.
hispida (Tracbelomonas),

32.
hispidipes (Leptodesmus),

472.
Mstolytica (Entamoeba),

16.
histrionica (Limnesia),

452.

hofmanni (Castrada), 163.
holmani (Chirocephalus),

330.

Holomisis, 91.
Holophrya, 51.
Holopidae, 621.
Holopus, 621.
Holosticha, 62.
Holostomata, 187.

Holostomum, 188.
Holothuria, 648.
Holothuriidae, 648.
Holothurioidea, 646.
Holotrichida, 50.
Homarus, 389.
hominis (Babesia), 47.
hominis (Sarcoptes), 440.
Homoccela, 75.
Hookworm, 223.
hooperi (Stylactis), 100.
Hoplonemertea, 209.
Hoplorhynchus, 45.
Horny mites, 442.
Horse leech, 320.
Horse mussels, 572.
Horse sponges, 84.
Horseshoe crabs, 400.
hortensis (Arion),527.
hortensis (Helix), 520.
hortorum (Leucauge), 427.
hufelandi (Macrobiotus),

458.

humilis (Lymnaea), 510.
huxleyi (Oikopleura), 659.
huxelyi (Pauropus), 467.
hyacinth! (Rhizoglyphus),

442.
hyacinthina (Periphylla),

128.

Hyalea, 498.
Hyalella, 367.
hyalina (Cryptops), 475.
hyalina (Daphnia), 335.
hyalina (Leptodora), 338.
hyalina (Lyonsia), 600.
hyalina (Schizoporella),

257.

hyalinis (Pamphagus), 21.
Hyalonema, 77.
Hyalonematidae, 77.
Hyas, 395.

hyatti (Rossia), 609.
Hybocodon, 102.
Hyctia, 435.
Hydatina, 237.
Hydatinidae, 237.
Hydra, 92.
Hydrachna, 449.
Hydrachnidae, 447.
Hydrachninae, 449.
Hydractinia, 100.
Hydractiniidae, 99.
Hydrallmania, 108.
Hydranth, 91.
Hydrariae, 92.
Hydrobiidae, 541.
Hydrocaulus, 91.
Hydrocladia, 108.
Hydrocorallinae, 93.
Hydroid type of structure,

87.

Hydroides, 302.
Hydroids, 86.
Hydromedusae, 90.
Hydrorhiza, 91.
Hydrotheca, 104.
Hydrozoa, 90.
Hydryphantes, 449.
Hydryphantinae, 449.
Hygrobates, 450.
Hygrobatinae, 450.
Hymenolepis, 199.
Hyperia, 365.
Hyperiidae, 365.
Hyperiidea, 365.
hypnorum (Aplexa), 512.
Hypobranchial gland, 528.
Hypopus, 441.
Hypostome, in hydroids,

91 ; in mites, 436.
Hypotrichida, 60.
Hyptiotes, 418.

IBLA, 360.
Ichthydium, 244.
Ichthyobdellidae, 317.
idae (Cristatella), 264.
Idothea, 376.
Idotheidae, 376.
Idyia, 154.
illecebrosus

(Ommastephes) , 610.
illinoisensis (Pleodorina),

38.

Illoricata, 235.
illuminatus (Bdellodrilus),

306.

Ilyanassa, 558.
imbicilis (Anodonta), 582.
imbricata (Dermasterias),

628.
imbricata (Harmothoe),

285.

immaculata (Natica), 538.
immacalata (Scutigerella),

466.

immitis (Filaria), 219.
imparispinosus

(Amphiporus), 211.
imperator

(Branchiocerianthus) , 91.
Imperforina, 20.
Imperial purple, 555.
implexa (Filograna), 302.
implicata (Anodonta), 581.
impressa (Loxochonca),

356.

impressus (Parajulus), 469.
incisa (Nephthys), 289.
incolorata (Persa), 120.
inconstans (Trichodrilus),

311.
Indentata (Vitrea), 525.

720

INDEX

Inflatus (Hexamitus), 31.
inflecta (Polygyra), 521.
Infrabasals, 619.
Infundibula, 665.
infundibulum

(Bolinopsis),153.
infusionum (Lembus), 57.
Infusoria, 48.
ingens (Nephthys), 289.
inhaerans ( Leptosy napta ) ,

651.

Ink sac, 603.

inquilina (Planocera), 170.
Insecta, of Linnaeus, 2,

326.

Insecta aptera, 326.
insectus (Cyclops), 346.
Insertion plate, 484.
insignis (Cotylaspis), 179.
instabilia

(Branchiobdella), 305.
insularis (Epeira), 426.
integer (Somatogyrus),

542.
Intermediate host,

180, 190.
Interproglottidal glands,

198.

Interradius, 614.
Interray, 614.
interrita (Dysdera), 419.
interrupta (Turbonilla),

554.

Intestina, 156.
intestinalis (Ciona),667.
intestinalis (Ligula), 193.
intestinalis

(Strongyloides),218.
Introvert, 273.
iris (Lampsilis),580.
irradians (Pecten), 575.
irrorata (Idothea), 376.
irrorata (Littorina), 540.
irrorata (Unicola), 371.
irroratus (Cancer), 396.
irrorotus (Tubifex), 310.
Ischnochiton, 488.
Ischnochitonidae, 487.
islandica (Cyprina), 578.
islandicum (Cardium),

593.

islandicus (Pecten), 575.
Isocrinus, 621.
Isopoda, 372.
Itch mite, 440.
Ivory barnacle, 362.
Ixodes, 446.
Ixodidae, 445.

, 378.
jamaicensis

(Balanoglossus), 654.

Janira, 378.

Janiridae, 378.

Janthina, 535.

Janthinidae, 535.

Jasis, 662.

Jaw, in brittle stars, 634 ;

in snails, 493.
Jellyfish, 86.
Jingle shell, 570.
Jonah crab, 396.
jonesi (Perigonimus), 97.
juli (Stenophora),44.
Julidae, 468.
Julus, 469.
Jumping spiders, 434.

KATHARINA, 489.
Keber's organ, 566.
Kellia, 585.
Kellyellidae, 585.
keraudreni (Oxygyrus),

553.

kessleri (Amphisia), 62.
kewensis (Placocephalus),

168.

Keyhole limpets, 531.
Keyhole urchin, 645.
King crabs, 400.
Kinorhyncha, 244.
Koenenia, 406.
Koenikea, 452.
Kowalevskia, 659.
Kowalevskiidae, 659.
kowalevskyi

(Dolichoglossus) , 655.

LABIDOCBRA, 345.

Labiosa, 590.

Labium (in arachnids),

414, 436.
labyrinthica (Strobilops),

517.
lacerata (Opercularella),

112.
laciniatum

(Anthobothrium), 196.
laciniatum

(Crossobothrium), 196.
laciniatus

(Bothriocephalus), 195.
Lacinularia, 234.
Lacrymaria, 51.
lactarium (Lysiopetalum),

471.
lacteum (Dendroccelum),

166.
lacteus (Cerebratulus),

209.

Lacuna, 541.
lacustris (Cordylophora),

95.
lacustris (Cristatella), 264.

lacustris (Epischura), 343.
lacustris (Spongilla), 81.
lacustris (Stylaria), 309.
Lady crab, 398.
Laevicardium, 593.
laevigata (Velutina), 538.
Isevis (Chirodota),651.
laevis (Elasmopus), 370.
laevis (Porcellio), 380.
laaviusculus (Calliopius),

369.

Lafcea, 117.
lagena (Halimocyathus),

127.
lagenella ( Trachelomonas ) ,

32.

lagenoides (Gromia),20.
lagenula (Lacrymaria), 52.
lambis (Pterocera), 549.
lamella tus ( Eury cercus ) ,

336.

Lamellibranchiata, 563.
lampas (Alcippe), 362.
Lampsilis, 579.
lanceolatum

(Branchiostoma), 673.
Land crabs, 394.
Land planarians, 168.
Land snails, 506.
languida (Oceania), 115.
Lantern of Aristotle, 640.
Laodice, 289.
Laodice viridis, 283.
Laodicea, 117.
Laodicidae, 289.
Laonice, 293.
lapidaria (Pomatiopsis),

543.

lapillus (Purpura), 556.
Laqueus, 269.
larix (Antipathes),139.
larus (Chaetonotus),243.
Larvacea, 657.
larynx (Tubularia), 103.
lasium

(Phoreiobothorium), 196.
Lateral teeth, of pelecypod

shell, 564 ; of radula,

480.

lateralis (Mactra), 590.
lateritia (Vampyrella), 22.
Lathrodectus, 421.
laticauda (Argulus), 352.
latithorax (Ebo),429.
lativentris (Cunina), 121.
Latona, 333.
latum (Diphyllobothrium),

194.
leanum (Cochlodesma),

601.

Leda, 569.
Leeches, 315.

INDEX

721

leidyi (Edwardsia), 140.
leidyi (Fabricia), 301.
leidyi (Marphysa), 290.
leidyi (Micrura), 208.
leidyi (Mnemiopsis), 153.
leidyi (Pristina), 309.
leidyi (Sthenelais), 286.
Lembadion, 56.
Lembus, 57.
Lemnisci, 229.
lentus (Anoplodactylus),

460.

lepadella (Metopidia), 242.
Lepadidae, 360.
Lepas, 360.
Lepeophtheirus, 350.
Lephthyphantes, 423.
Lepidoderma, 243.
Lepidonotus, 285.
Lepidopleuridae, 486.
Lepraea, 296.
Lepralia, 257.
Leptocardia, 671.
Leptocheirus, 370.
Leptochela, 374.
Leptoclinum, 671.
Leptodesmus, 472.
Leptodora, 338.
Leptodoridae, 338.
Leptomedusae, 104.
Leptoplana, 170.
Leptoplana gigas, 158.
Leptoplanidae, 170.
leptopus (Diaptomus), 344.
leptostyla (Clava),95.
Leptosynapta, 651.
Lernaea, 350.
Lernaeidae, 350.
Lernaeopoda, 351.
Lernaeopodiae, 351.
Lerneaenicus, 350.
lessoni (Polycera), 501.
Leucandra, 76.
leucas (Frontonia), 55.
Leucauge, 427.
leuckarti (Cyclops), 346.
leuckarti (Podon), 338.
leucolena (Sagartia), 144.
Leucon type of sponge, 72.
Leuconidae, 76.
leucophseta (Congeria),

584.
leucops (Stenostomum),

161.
leucoptera (Stoloteuthis),

609.

Leucosolenia, 75.
Leucosoleniidae, 75.
Levant sponges, 84.
Liacarus, 443.
Libinia, 395.
Lichenopora, 251.

Lichenoporidae, 251.
Lichnophora, 64.
Lichnophoridae, 64.
Ligament, in Acanthoce-

pala, 229 ; in pelecypods,

564.
ligamentina (Lampsilus),

580.

ligera (Gastrodonta), 526.
lignorum (Liranoria), 375.
Ligula, 193.
Ligulinae, 193.
Llgyda, 380.
Ligydidae, 380.
lilacea (Tubulipora), 251.
lima (Exuviella), 40.
lima (Philine),498.
Limacidae, 526.
Limacina, 498.
limacina (Clione), 499.
Limacinidae, 498.
Limapontia, 505.
Limapontiidae, 505.
limatula (Yoldia), 568.
Limax, 526.
limax (Amoeba), 16.
Limax lanceolatus, 672.
limbata (Nereis), 288.
Limnadiidae, 331.
limnaei (Chaetogaster),

310.

Limnesia, 451.
Limnetis, 332.
Limnias, 233.
limnicola (Nereis), 288.
Limnicythere, 356.
Limnocalanus, 342.
Limnochares, 448.
Limnocharinae, 448.
Limnocnida, 91.
Limnocodium, 119.
Limnodrilus, 311.
Limnoria, 375.
Limnoriidae, 375.
limosa (Amnicola), 542.
limosa (Dero),309.
limosus (Cambarus), 392.
Limpets, 530.
limpida (Vitrina), 525.
Limulus, 402.
lineare (Microstomum),

162.
linearis (Cephalothrix),

206.
lineata (Edwardsiella),

140.
lineata (Glossiphonia),

318.

lineata (Labiosa), 590.
lineata (Scalaria), 535.
lineata (Tonicella), 488.
lineatus (Gordius). 227.

Uneatus (Heliodiscus), 523.
lineatus (Melampus), 508.
Lineidae, 207.
Lineus, 207.
Linguatula, 457.
Linguatulida, 455.
Lingula, 267.
Lingulidae, 267.
Linnaean Classification, 1.
linnaeana (Porpita), 123.
Linotaenia, 474.
linterni (Tyroglyphus),

442.

lintoni (Myxobolus), 48.
Linuche, 128.
Linyphia, 423.
Linyphiidae, 422.
Liobunum, 412.
Lionotus, 53.
Lloplax, 544.

Lip (in snail shells), 506.
Llriope, 120.
Lithobiidae, 476.
Lithobius, 476.
Lithocyst, 105.
Litliodomus, 573.
Lithophagus, 573.
lithophagus

(Lithophagus), 573.
Lithotrya. 360.
litoralis (Paranais), 309.
litoralis (Zygeupolla),

208.

litorea (Littorina), 540.
litterata (Oliva),560.
littorale (Pycnogonum),

459.

littoralis (Asterias), 632.
Littorina, 540.
Littorinidae, 539.
Liver fluke, 183.
Liver sacs, 659.
livescens (Goniobasis), 547.
Livoneca, 375.
Lizzia, 98.
loa (Filaria),219.
Lobata, 152.
lobatum

(Siphonodentalium), 492.
lobostoma (Diffugia), 17.
Lobsters, 389.
locusta (Gammarus), 369.
locustae-carolinae

(Gregarina),44.
locustarum (Trombidium),

454.
lofotensis (Rhlzocrinus),

621.

Loliginidae, 609.
Loligo, 609.
Loligopsis, 612.
Lone-star tick, 446.

722

INDEX

Long clam, 594.
longicarpus (Pagurus),

393.
longicauda

(Appendicularia), 658.
longicauda (Cercomonas),

27.
longicauda (Microcotyle),

177.
longlcaudatus ( Uroleptus ) ,

62.
longicaudum (Scaridium),

240.

longicaudus (Phacus),32.
longicornis (JEginella),

372.
longicornis (Talorchestia),

367.

longicornis (Temora), 342.
longimana (Amphithoe),

371.

longipalpis (Erigone), 423.
longipalpis (Hygrobates),

450.
longirostris (Bosmina),

336.

longiseta (Rattulus), 241.
longispinatus

(Stephanops),240.
longispinosus

Chaetonotus), 243.
longissimum ( Hyalonema) ,

78.

longitarse (Nymphon), 461.
loossi (Azygia), 185.
Lophophore, in Brachiopo-

da, 266 ; in Bryozoa, 245 ;

in Phoronidea, 270.
Lophopus, 263.
Lorica, 231.
Loricata, 239.
loricata (Gemellaria),

253.

loveni (Gonothyrea), 112.
Loxoconcha, 356.
Loxophyllum, 53.
Loxosoma, 247.
Loxosomidae, 247.
Lower worms, 155.
lulbocki (Pauropus), 467.
lubrica (Cochlicopa), 518.
lubricalis (Nicomache),

299.
lucayanum (Asymmetron),

673.

lucasanus (Apus),331.
lucens (Metridia),342.
Lucernaria, 127.
Lucernariidae, 126.
luciae (Sagartia), 144.
Lucina, 585.
Lucinidae, 584.

lugubris (Planaria), 166.
Luidia, 626.

lumbrici (Monocystis), 46.
lumbricalis (Nicomache),

299.

Lumbricidae, 312.
Lumbricillus, 307.
lumbricoides (Ascaris),

224.

Lumbriconereis, 290.
Lumbriculidae, 311.
Lumbricus, 312.
Lumbrinereis, 290.
luna (Cathypna), 241.
lunata (Columbella), 557.
Lungs (in arachnids), 403.
Lunule, 564.
lurida (Ostrea), 575.
luridus (Notomastus), 297.
lutarium (Didemnum),

671.

luteola (Lampsilis), 580.
luteolum {Leptoclinum) ,

671.

Lycophora, 192.
Lycosa, 433.
Lycosidae, 432.
Lymnaea, 509.
Lymnseidae, 509.
Lynceidae, 336.
lyncurium (Tethya), 79.
Lyonsia, 600.
Lyonsiidae, 600.
Lysiopetalidae, 471.
Lysiopetalum, 471.
Lytechinus, 643.

MACPARLANDI

(Lichnophora), 64.
Macoma, 588.
macricaudatum

(Asymmetron), 673.
Macrobdella, 320.
Macrobiotus, 458.
macrocephala

(Ampelisca), 368.
Machrocheles, 444.
Macronucleus, 49.
macrostoma (Nassula), 54.
macrourus (Asellus), 377.
Macrura, 385.
Macrura natantia, 385.
macrurus (Limnocalanus),

342.
mactans (Lathrodectus),

421.

Mactra, 589.
mactracea (Crassatellites),

577.

Mactridae, 589.
maculata (Goniada), 291.
maculata (Planaria), 165.

maculatus (Pinnotheres),

399.
maculatus

(Rhyncholophus), 454.
maculosa (Ilarrimania),

655.

Madrepora, 146.
Madreporaria, 145.
Madreporite, 616.
mamas (Carcinides), 398.
magdalenenis

(Ischnochiton), 488.
magellanicus (Pecten),

575.

magister (Cancer), 397.
magna (Conchaecia), 358.
magna (Fasciola), 184.
magna (Sphaerophrya), 67.
magniflca (Pectinatella),

264.

magnum (Cardium), 593.
Maiidae, 395.
Malacobdella, 213.
Malacocotylea, 172.
Malacostraca, 363.
Malaria, 47.

malariae (Plasmodium), 47.
Maldane, 298.
Maldanidae, 298.
Mallomonas, 35.
Mammary organ, 247.
mananensis (Coryphella),

504.

Manayunkia, 301.
Mancasellus, 377.
Mandibles, 323.
Mange mite, 440.
Mangora, 427.
manhattensis (Molgula),

665.
Mantle,

in Brachiopoda, 265 ;

in Mollusca, 478 ;

in Tunicata, 655.
Mantle cavity

(in mollusks), 479.
Manubrium, 88.
Margarita, 533.
Margaritana, 582.
margaritifera

(Margaritana), 582.
margaritifera

(Meleagrina),573.
Margaropus, 446.
Marginal teeth (of radula),

480.

marginata (Linyphia), 423.
marginata (Taenia), 201.
marginatum

(Clinostomum), 187.
marginatum (Metridium).

144.

INDEX

723

marginatus (Pupoides),

516.
marginatus (Spirobolus),

470.

Maricola, 167
marina (Arenicola), 299.
marina (Bdella), 453.
marina (Idothea), 376.
marina (Jsera), 378.
marina (Oxyrrhis), 30.
marina (Vorticella), 66.
Marine triclads, 167,
marinum (Uronema), 55.
marinus (Scutovertex),

443.

marinus (Tubulus), 490.
marmoratis (Haemopis),

320.

marmoratus (Conus), 562.
marmoratus (Turbo), 533.
marmorea (Tonicella), 487.
Marphysa, 290.
Marpissa, 435.
Marptusa, 435.
marshalli (Arrhenurus),

452.

marxi (Pirata), 434.
Mastax, 231.
Mastigamoeba, 26.
Mastigophora, 24.
Mastigoproctus, 407.
Maw worm, 225.
Maxilla,

in crustaceans, 327 ;

in spiders, 414 ;

in mites, 436.
Maxilliped,

in crustaceans, 363 ;

in myriapods, 464, 473.
maximus (Doryaimus),

216.

maximus (Limax), 527.
Meandrina, 148.
meandrites (Meandrina),

148.

Mediaster, 627.
Medicinal leech, 320.
medicinalis (Coras), 431.
medicinalis (Hirudo),

320.

Medina worm, 220.
medinensis (Filaria), 220.
mediterranea (Carinaria),

552.

Medusa, 71, 88.
Medusa type of structure,

88.
medusarum (Hyparia),

366.
megalocephala (Ascaris),

225.
Megalopa, 394.

Megalotrocha, 234.
Megascleres, 73.
Megascolicidae, 311.
megasoma (Lymnsea), 509.
Megninia, 441.
megotara (Teredo), 599.
Melampus, 508.
melanopli (Gregarina), 44.
Meleagrina, 573.
meleagris (Stomolophus),

131.

Melicerta, 233.
melicerta (Melicerta), 233.
melicerta (Oecistes), 234.
Melicertidae, 233.
Melicertum, 117.
Mellita, 644.

melitta (Thalassema), 315.
Membranipora, 255.
Membraniporidae, 255.
mendicaria (Hanleyia),

486.

Menipea, 253.
Menoidium, 33.
Menosporidae, 45.
mercenaria (Venus), 590.
meridionalis ( Comactinia ) ,

623.

Mermis, 218.
Mermitidae, 218.
Merozoites, 46.
Mertensia, 152.
Mesenchytrseus, 308.
Mesenteries, 132.
Mesodinium, 52.
Mesoglea, 70.
Mesonemertini, 205.
Mesoplacophora, 486.
Mesostoma, 163.
Metacnemes, 138.
nietallica (Idothea), 376.
Metanemertini, 209.
Metapodium, 479.
Metasoma, 279.
Metastomium, 277.
Metazoa, 4.
Metopidia, 242.
Metoponorthus, 380.
Metopus, 58.
Metridia, 342.
Metridium, 144.
mexicana (Holothuria),

649.

mexicanus (Vejovis), 405.
Meyenia, 81.
Miana bug, 445.
Micaria, 430.
michelini (Encope), 645.
Micrathena, 426.
Microciona, 83.
Microcotyle, 177.
Microcotylinae, 177.

Microhydra, 118.
Micronucleus, 49.
Microphallus, 186.
microphthalma (Sabella),

301.

Microporella, 256.
Microporellidae, 256.
Microscleres, 73.
Microstomidae, 162.
Microstomum, 162.
Micrura, 208.
miescheriana

(Sarcocystis),48.
miliaris (Noctiluca), 42.
militaris (Brachionus),

240.

militaris (Pteraster), 631.
milium (Vertigo), 517.
milium (Zonitoides), 526.
milleri (Hydractinia), 100.
Millepora, 93.
Milleporidae, 93.
Millipeds, 467.
minax (Uca), 400.
miniata (Asterina), 629.
minnehaha (Daphnia),

334.

minor (Calanus), 341.
minus (Alpheus), 388.
minuscula (Zonitoides),

526.

minuta (Loxosoma), 247.
minuta (Phloe'), 285.
minuta (Rissoa), 541.
minuta (Turtonia), 585.
minutum (Nemasoma),

469.

minutus (Argas), 445.
minutus (Canthocamptus),

348.
minutus (Diaptomus),

344.

mira (Eutima), 115.
mira (Pisaurina), 432.
mirabilis (Syncoryne), 96.
Miracidium, 180.
Misumena, 428.
Mitella, 360. v
Mitellidae, 359.
Mites, 436.
Mitra, 560.
Mitridae, 560.
Mnemiidae, 153.
Mnemiopsis, 153.
modesta (Cornulariella),

134.

modesta (Sagartia), 144.
Modiolaria, 572.
Modiolus, 572.
modiolus (Modiolus), 572.
moestus (Macrocheles),

444.

724

INDEX

Moina, 335.
Moira, 645.
Molgula, 664.
Molgulidae, 664.
molguloides

(Bostrichobranchus) ,

665.

mollis (Reoiera), 83.
mollissima (Euspongia),

84.

Mollusca, 478.
Molluscoidea, 246.
Molpadiidae, 650.
Monactinellida, 79.
Monadida, 26.
Monas, 28.

moneta (Cypraea), 494, 549.
Moniezia, 198.
moniliaris (Polydesmus),

472.

Monocotyle, 174.
Monocotylidae, 174.
Monocystis, 46.
monodon (Polygyra), 521.
Monogenea, 173.
Monogenetic trematodes,

173.

Monopectinate gill, 529.
Monosiga, 29.
monostachys

(Membranipora), 256.
Monostaechas, 109.
Monostomata, 181.
Monostyla, 241.
Monotocardia, 534.
Monotremata, 514.
montagui (Pandalus), 387.
Monura, 242.
Mopalla, 488.
Mopaliidae, 488.
morgani (Chordodes), 228.
morgani (Planaria), 166.
morsel (Cyzicus), 332.
morsitans (Scolopendra),

475.
mortonl (Laevicardium),

593.

morum (Pandorlna), 38.
Mosaic vision, 324.
Mother-of-pearl, 479, 564.
mucedo (Cristatella), 264.
Mucket, 580.
mucosa (Mopalia), 488.
mucosus (Rattulus), 241.
mucronata (Salpa), 662.
mucronata

(Scaplioleberis),335.
mucronatus

(Carinogammarus), 370.
Mucronella, 258.
Mud crabs, 397.
Mud snails, 557,

miilleri (Geodia* , 78.
Multiceps, 202.
multiceps

(Asplanchnopus), 237.
multiceps (Multiceps), 202.
multidentatus (Lithobius),

476.
multiformis (Phidippus),

435.
multilineata (Polygyra),

521.
multioculatus

(Proneurotes), 211.
Multistigmatea, 661.
Multivalvia, 481.
muraria (Dictyna), 418.
murarium (Theridion),

422.
murbachi (Gonionemus),

118.

Murex, 555.

muricata (Acropora), 146.
muricata (Pinna), 574.
muricatus (Chelifer), 410.
Muricidae, 555.
murrayana (Bugula), 254.
muscae domesticae

(Herpetomonas), 27.
muscorum (Obisium), 410.
muscorum (Pupilla), 516.
muscosa (Mopalia), 488.
Mushroom coral, 150.
Mussel crab, 399.
Mussels, 571.
mutabile (Cyclocoelum),

181.
mutabilis (Pamphagus),

21.
mutans (Cnemidocoptes),

440.
mutans (Pedicellina),

248.

mutica (Olivella), 560.
mutica (Pelia),396.
mutica (Velella), 123.
Mya, 594%
Myacea, 594.
Myidae, 594.
Myocytes, 72.
Myodocopa, 357.
Myonemes, 49.
myosotis (Phytia), 508.
Myriapoda, 463.
myriapoda (Heterophrys),

23.

Myriozoidae, 257.
Mysidae, 382.
Mysis, 382.

tnystax (Ascaris), 225.
mytili (Alcyonidium), 259.
Mytilidae, 571.
Mytilus, 571.

mytilus (Stylonychia), 63.
Myxicola, 301.
Myxobolidae, 48.
Myxobolus, 48.
Myxospongiae, 85.
Myxosporidiida, 48.
Myzorhynchus, 196.
Myzostoma, 322.
Myzostomida, 321.

N.EVIA (Agelena), 431.

Nagana, 30.

Naiades, 578.

Naididae, 308.

Nais, 308.

nana (Hymenolepis), 200.

Nanomia, 124.

Narcomedusae, 120.

Nassa, 557.

Nassidae, 557.

Nassula, 54.

nasutum (Didinium), 52.

Natica, 537.

Naticidae, 537.

Nauplius, 327.

Nausithoe, 128.

Nautilidae, 606.

Nautiloidea, 606.

Nautilus, 606.

navalis (Teredo), 599.

Nebalia, 364.

nebulifera (Vorticella), 65.

nebulosa (Planocera),169.

nebulosus

(Lephthyphantes), 423.
Necator, 222.
Nectonema, 228.
Nectonematidae, 228.
Nectophores, 122.
neglectus (Drassus), 419.
Nemasoma, 469.
Nemastomatidae, 413.
Nematelmia, 157.
Nemathelminthes, 213.
Nematocyst, 86.
Nematodes, 214.
Nematophore, 108.
Nemertea, 203.
Nemertians, 203.
Nemopsis, 98.
nemoralis (Helix), 520.
Neocomatella, 622.
Neoliodes, 443.
Neomenia, 484.
Neomeniidae, 483.
Neomeniina, 483.
Neopanopeus, 397.
Neosporidia, 47.
Nephridium, 278.
nephropis (Stichocotyle),

178.
Nephropsidae, 389,

INDEX

725

Nephthydidae, 289.

Nephthyidae, 135.

Nephthys, 289.

Neptunea, 558.

Nereidae, 288.

Nereidiformia, 283.

Nereis, 288.

Nerita, 534.

Neritidae, 534.

Nettle organ, 86.

Neuropodium, 282.

nickliniana ( Paludestrina ) ,
543.

Nicomache, 299.

Nidamental glands, 604.

nidicola (Lycosa), 433.

niger (Ariolimax), 528.

nigra (Ascidia), 667.

nigra (Modiolaria), 572.

nigrescens (Astacus), 390.

nigrescens (Mermis), 219.

nigrocincta (Triforis), 546.

nigropalpis (Pardosa),
433.

nigrum (Bittium), 546.

nigrum (Botrylloides), 669.

niloticus (Trochus), 532.

nitida (Plumatella), 263.

nitida (Zonitoides), 525.

nitidulum (Chaetoderma),
484.

nitidus (Liacarus), 443.

Nitzschia, 174.

nivea (Scutigerella), 466.

noae (Area), 571.

Noah's ark, 571.

nobile (Corallium), 135.

Noctiluca, 42.

nodiferus (Triton), 551.

nodulosa (Bunodera), 185.

nordmanni (Evadne), 338.

Northern crab, 396.

norvegica (Teredo), 599.

Noteus, 240.

Nothrus, 443.

Notochord, 652.

Notomastus, 297.

Notommata, 238.

Notommatidae, 237.

Notopodium, 282.

Notops, 237.

Nuclearia, 22.

Nucleus (in Salpa), 660.

Nucula, 568.

Nuculidae, 568.

Nuda (Ctenophora), 154.

Nuda (Rhizopoda), 119.

Nudibranchiata, 500.

nudus (Sipunculus), 274.

Number of described spe-
cies, 10.

nutans (Pedicellina), 248.

Nut-brown cowry, 550.
nutricula ( Turritopsis ) ,

102.
nuttalliana (Fluminicola)

542.

Nuttallina, 488.
Nymph (in mites), 437.
Nymphon, 461.
Nymphonidae, 460.

OBELIA, 113.

obesa (Clubiona), 429.

obiculare (Tanystylum),

460.

obiculata (Helicina), 534.
obliqua (Succinea), 518.
Obisiidae, 410.
Obisium, 410.
oblonga (Clavelina), 668.
oblongum (Polystoma),

175.

oblongus (Chelanops), 410.
oblongus (Tibellus), 429.
obrussa (Lymnsea), 510.
obscura (Margarita), 533.
obscura (Podarke), 288.
obsoleta (Nassa), 558.
obtusa (Dero), 309.
occidentale (Dentalium),

491.
occidentale (Sphaerium),

586.
occidentalis (Aporrhais),

549.
occidentalis (Cotylogaster),

178.
occidualis (Halipegus),

187.

Oceania, 115.
oceanica (Ligyda), 380.
ocellata (Halopsis), 116.
Ocellate sense organs, 89.
ocellatus (Ovalipes), 398.
ochracea (Asterias), 632.
ochracea (Ectopleura),

102.
ochraceus (Amphiporus),

211.

Octocotylinae, 176.
octonaria ( Cunoctantha ) ,

121.

Octopoda, 612.
Octopodidae, 613.
Octopus, 613.
Ocular plate, 640.
oculata (Chalina), 82.
oculifera (Potamilla), 301.
Oculina, 147.
Oculinidae, 147.
Ocypoda, 399.
Ocypodidae, 399.
Odinia, 633.

Odostomia, 554.

Oecistes, 234.

Oerstedia, 213.

Oesophageal bulb, 214.

officinalis (Euspongia), 84.

offlcinalis (Sepia), 608.

ohionis (Palaemon), 387.

Oikomonas, 27.

Oikoplast, 658.

Oikopleura, 658.

Oithona, 347.

oleacea (Eulima), 553.

oligactis (Hydra), 92.

Oligochseta, 303.

Oliva, 560.

olivacea (Ophioderma),
636.

Olivella, 560.

Olividae, 560.

olor (Lacrymaria), 52.

Ommastrephes, 610.

Ommastrephidae, 610.

Ommatoids, 407.

Omphalina, 524.

Onchidella, 515.

Onchidiidae, 515.

Onchidoris, 502.

Onchobothriidae, 195.

Onchosphere, 190.

Onicidae, 378.

Oniscus, 378.

Onychodromus, 62.

Onychophora, 462.

Onychoteuthidae, 611.

Onychoteuthis, 611.

Ooecium, 248.

opacus (Microphallus), 186.

Opalina, 57.

opalina (Arabella), 291.

Opalinidae, 57.

Opercularella, 112.

Opercularia, 67.

operculatum (Amphi-
dinium), 41.

Operculum :

in Bryozoa, 249 ; in Gas-
tropoda, 492 ; in Hydro-
medusae, 104; in Limu-
lus, 401 ; in Polychseta,
302.

Opheliidae, 298.

Ophiacantha, 637.

Ophiacanthidae, 637.

ophidioidea (Cristatella),
264.

Ophioderma, 636.

Ophiodermatidae, 635.

Ophiolepididae, 636.

Ophiomyxa, 637.

Ophiomyxidae, 637.

Ophiopholis, 636.

Ophiothrix, 637.

726

INDEX

Ophiotrichidae, 637.
Ophiura, 636.
Ophiurae, 635.
Ophiuroidea, 633.
Opisthobranchiata, 495.
Oral disc, 132.
Oral groove, 49.
Oral palp, 565.
Oral papillae, 634.
Oral plates, 634.
Oral surface, 614.
Oral tentacles (in holo-

thurlans),646.
Orbicella, 148.
orbiculata (Helicina), 534.
orbiculatum (Didemnum),

671.

Orchestia, 367.
Orchestiidae, 366.
Oreaster, 628.
Oreasteridae, 628.
oregonensis (Diaptomus),

343.

Organs of Cuvier, 646.
Oribata, 443.
Oribatidae, 442.
ornata (Amphitrlte), 295.
ornata (Aricia), 292.
ornata (Floscularia), 233.
ornata (Nassula), 54.
ornatum (Scalpellum), 359
Oroperipatus, 463.
Orthoceras, 606.
Orthoneurous gastropods,

494.

Orthurethra, 507, 514.
Orygmatobothrium, 196.
oryza (Cylichnella), 497.
Osculum, 72.

osleri (Sphyranura), 176.
Osphradium, 480.
Ostracoda, 352.
Ostrea, 574.
Ostreidae, 574.
ostreum (Pinnotheres),

399.

Otoporpae, 121.
Ovalipes, 398.
ovalis (Livoneca), 375.
ovalis (Succinea),518.
ovalis (Succinea), 519.
ovata (Boroe), 154.
ovata (Cryptomonas), 36.
ovata (Monosiga), 29.
ovata (Vertigo), 517.
Ovicell, 248.
Ovigerous legs, 458.
ovis (Psoroptes), 440.
Ovulum, 550.
ovum (Mertensia), 152.
ovum (Ovulum), 550.
Oxygyrus, 553.

Oxyrhyncha, 395.
Oxyrrhis, 30.
Oxytricha, 62.
Oxytrichidae, 61.
Oxyuris, 225.
Oyster crab, 399.
Oyster drill, 556.
Oysters, 574.

PACHYLOMERUS, 416.
pachyurus (Copeus), 238.
Pacific palolo worm, 283.
pacifica (Phoronis), 271.
Paguridae, 393.
Pagurus, 393.
Palsemon, 387.
Palsemonetes, 386.
Palsemonidae, 386.
Paleonemertea, 205.
Palinuridae, 392.
Palinurus, 392.
Palisade worm, 224.
pallasi (Eichiurus), 315.
pallasiana (Lepralia), 258.
Pallene, 460.
Pallenidae, 460.
Pallets, 598.
Pallial line, 564.
Pallia! sinus, 564.
palliata (Littorina), 540.
palliata (Polygyra), 521.
pallida (Loligo), 610.
pallida (Onchidoris), 502.
pallida (Syllis), 287.
pallidum (Treponema), 26.
pallidus

(Asteracanthion), 632.
pallidus

(Stauronereis), 291.
Pallifera, 528.
pallipes (Eremobates), 408.
Palm crab, 393.
palmata (Acropora), 146.
palmata (Pista), 295.
Palolo worm, 283.
Palpal organ, 414.
Palpi, 414.
Palpigradi, 406.
Paludestrina, 543.
Paludicella, 261.
Paludicellidae, 261.
Paludicola, 165.
Paludina, 544.
Paludinidae, 543.
paludosa (Palffimonetes),

387.

palustris (Attus), 434.
palustris (Helodrilus), 314.
palustris (Lymnsoa), 510.
palustris (Orchestia), 367.
palustris (Pelomyxa), 15.
Pamphagus, 20.

pandalicola (Probopyrus),

381.

Pandalus, 387.
Pandoridae, 600.
Pandorina, 37.
panicea (Halicondria), 83.
Panopeus, 397.
Pantopoda, 458.
papalis (Mitra), 560.
Paper nautilus, 612.
papillosa (Aeolis), 503.
papillosa (Molgula), 665.
papposus (Solaster), 630.
Papulae, 623.
Paractidae, 143.
Paractinopoda, 650.
Paractis, 143.
Paragonimus, 184.
Paragordius, 227.
Parajulus, 469.
parallelus (Ancylus), 513.
parallelus (Heliodiscus),

523.

Paramecidae, 55.
Paramecium, 56.
paramecium (Chilomonas),

36.

Paramphistomidae, 182.
Paramphistomum, 182.
Paramylum, 31.
-Paranais, 309.
Parapod, 465.
Parapodium, in annelids,

277, 282; in mollusks,

479.

Parapolia, 207.
parasitica (Glossiphonia),

318.
parasiticum (Bicidium),

142.

Parategastes, 348.
Pardosa, 433.
Parenchyma, 156.
Parietal lip and tooth (of

snail shells), 506.
parma (Echinarachnius),

644.

Parthenogenesis, in Ostra-
coda, 353 ; in Phyllopoda,

333 ; in Rotifera, 231.
Parthenogonidia, 39.
partita (Styela), 666.
parva (Fredericia), 307.
parvula (Nais), 308.
parvus (Planorbis), 513.
Parypha, 104.
passerinus (Analges), 441.
Patella, 530.
Patelliform, 530.
patellina (Vorticella), 66.
patens (Condylos'toma), 59.
patina (Acmsea), 530.

INDEX

727

patina (Pterodina), 239.
paulum (Orygmatoboth-

rium), 196.
Pauropoda, 466.
Pauropodidae, 466.
Pauropus, 467.
pavo (Calocalanus), 341.
pavo (Loligopsis), 612.
Paxillae, 623.
peachi (Mucronella), 258.
Peacock squid, 612.
pealei (Loligo), 609.
Pear leaf blister, 438.
Pearl oyster, 573.
Pearls, 564.
Pearly nautilus, 606.
pecten, 575.
Pectinaria, 297.
Pectinatella, 264.
Pectinibranchiata, 534.
Pectines, 405.
Pectinidae, 575.
pectorale (Gonium), 37.
Pedal disc, 132.
Pedalia, 128.
Pedicellariae, 623.
Pedicellina, 248.
Pedicellinidae, 248.
pediculus (Polyphemus),

338.

pediculus (Trichodina), 65.
pediculus (Trivia), 550.
Pedipalp, 402, 414.
Pedipalpi, 406.
Peduncle, in Brachiopoda,

265 ; in Crustacea, 363.
Pegea, 662.
Pelagia, 129.

pelagica (Floscularia), 233.
pelagica (Halocypris), 358.
pelagica (Nereis), 288.
pelagica (Physalia), 124.
pelagica (Scyllsea), 500.
pelagica (Thalassicolla),

24.

Pelagiidae, 129.
Pelecypoda, 563.
Pelia,, 396.

pellionella (Oxytricha), 62.
pellucida (Cuspidaria), 602.
pellucida (Carinella), 206.
pellucida (Molgula), 665.
pellucidum (Amaroucium),

670.
pellucidum (Menoidium),

33.
pellucidum (Synccelidium),

168.
pellucidus (Cambarus),

392.
pellucidus (Chaetogaster),

310.

Pelomyxa, 15.
Peltogaster, 363.
Pen (in Cephalopoda), 608.
pendula (Corymorpha),

101.

Peneidae, 388.
Peneus, 388.
Pennaria, 101.
Pennariidae, 100.
Pennatula, 137.
Pennatulacea, 137.
Pennatulidae, 137.
pennsylvanica (Tubella),

82.
pennsylvanicus

(Chthonius), 410.
pennsylvanicus

( Para julus), 470.
Pentaceros, 628.
Pentacrinidae, 621.
Pentastomum, 457.
pentodon (Bifldaria), 516.
Pepper coral, 93.
Peranema, 33.
Peranemidae, 33.
Peretreme, 444.
perfoliata

(Anoplocephala), 198.
Perforata, 146.
Perforina, 21.
pergamentaceus

(Chaetopterus),293.
Peribranchial space, 665.
Peridinidae, 40.
Peridinium, 40.
Perigonimus, 97.
Periopod, 363.
Periostracum, 479, 564.
Peripatidae, 463.
Peripatus, 463.
Peripharyngeal band, 656.
Periphylla, 127.
Periphyllidae, 127.
Periproct, 638.
Perisarc, 91.
Peristomal gills, 640.
Peristorne, in echninoderms,

623, 638; of snail shell,

506.

Peristomium, 277.
Peritrichida, 64.
Periwinkles, 540.
Peronia, 121.
peroni (Atlanta), 552.
peroni (Spirula), 607.
Perophora, 668.
Persa, 120.

persicus (Argas),445.
perspectiva ( Py ramidula ) ,

522.
perspectivus (Sigaretus),

538.

pertusa (Lepralia), 258.
perversa (Triforis), 546.
perversum (Busycon), 559.
Petaloid area, 639.
Petasidae, 118.
Petricola, 592.
Petricolidae, 592.
pexata (Area), 571.
Phacus, 32.
Phagocata, 167.
Phalangiida, 410.
Phalangiidae, 411.
phalangioides (Pholcus)

420.

Phalangium, 412.
phaleratus (Cyclops), 347.
Phanerozonia, 626.
phantapus (Psolus), 650.
pharygiana (Hippasteria),

627.

Phascolion, 275.
Phascolosoma, 275. •
Phidippus, 434.
philadelphicus

(Bdellodrilus), 306.
Philine, 498.
Philinidae, 497.
Philodina, 235.
Philodinidae, 235.
Philodromus, 428.
Philomycidae, 528.
Philomycus, 528.
Philoscia, 379.
Phlegmacera, 413.
phcenicopterus

(Trachelocerca) , 52.
Pholadacea, 597.
Pholadidae, 597.
pholadiformis

(Petricola), 592.
Pholas, 597.
Pholcidae, 420.
Pholcus, 420.
Pholoe, 285.
Phonorhynchus, 163.
Phoreiobothrium, 196.
Phormosoma, 642.
Phoronidea, 270.
Phoronis, 270.
phosphorea (Idothea), 376.
phosphoreus (Polycirrus),

296.

Photidae, 370.
Phragmocone, 607.
Phragmophora, 607.
Phronima, 366.
Phronimidae, 366.
Phrurolithus, 429.
phrygiana (Linyphia), 423.
Phryxus, 381.
Phyla of Animal Kingdom,

Key to, 10.

728

INDEX

Phylactolaemata, 262.
Phyllobothriidae, 196.
Phyllobothrium, 197.
Phyllocarida, 364.
Phyllodoce, 286.
Phyllodocidae, 286.
Phyllomitus, 30.
Phyllopoda, 329.
Phylodromus, 428.
Physa, 511.
Physalia, 124.
Physaliidae, 124.
Physcosoma, 275.
Physidae, 510.
Physonectae, 124.
Phytia, 508.
Phytoflagellida, 34.
Phytopidae, 438.
Phytoptus, 438.
picta (Nephthys),289.
picta (Sthenelais),286.
pigra (Cryptoglena), 32.
pikei (Hyctia), 436.
pikei (Lycosa),433.
pilata (^olidia),503.
plleus (Pleurobrachia),

152.

Pilidium, 205.
Pill bugs, 380.
pilosa (Membranipora),

255.

pilularis (Eugyra), 665.
Pilumnidae, 397.
Pin worm, 225.
pingius

(Leptocheirus),370.
Pinna, 574.
Pinnae (in Ctenophora),

150.

Pinnotheres, 399.
Pinnotheridae, 399.
Pinnulae, 137.
pinnulatum (Cardium),

593.

Pinnules, 619.
Piona, 451.
Pirata, 434.
piratica (Pirata), 434.
piri (Eriophyes), 438.
Piroplasma, 47.
Pisauridae, 431.
Pisaurina, 432.
Piscicola, 317.
Pisidium, 587.
Pista, 295.

pistacia (Eulalia), 286.
Placocephalus, 168.
Plagiostomidae, 164.
Plagiotomidae, 58.
Plagiostomum, 164.
Plakopus, 15.
plana (Crepidula), 539.

Planaria, 165.
Planarians, 165.
Planariidae, 165.
planissima (Moniezia), 198.
Planocera, 169.
Planoceridae, 169.
Planorbidae, 512.
Planorbis, 512.
planorbis (Skenea), 543.
Planula, 88.

planulata (Kellia), 585.
Plasmodium, 46.
Platelmia, 157.
Plathelminthes, 156.
Platydorina, 38.
Platygyra, 149.
PlatyonicTius, 398.
Platypoda, 536.
platyptera ( Polyarthra) ,

237.

Pleodorina, 38.
Pleopod, 363.
Plerocercoid, 191.
Plerocercus, 191.
Plesiof ungiidae, 149.
Pleurobrachia, 152.
Pleurobrachiidae, 152.
Pleurobranchs, 384.
Pleurocera, 547.
Pleuroceridae, 546.
Pleuronema, 56.
Pleuronemidae, 56.
Pleurotomidae, 562.
Pleuroxus, 337.
Plexaurella, 137.
Plexauridae, 136.
plica tills

(Spriocheta),26.
plicatula

(Modiola), 572.
Ploima, 235.
Plumatella, 263.
Plumatellidae, 262.
plumicosa (Cellepora), 259.
plumipes (Uloborus), 417.
Plumulariidae, 108.
Pluteus, 614, 634, 641.
pluvialis

(Stephanosphaera), 37.
Pneumatophore, 122.
Pneumonoeces, 185.
Pneumonyssus, 437.
Pocket book clam, 580.
podagrosus (Phidippus),

435.

Podarke, 288.
Podia, 616.
Podobranchs, 384.
Podocopa, 353.
Podocoryne, 100.
Podocorynidae, 100.
Podon, 338.

Podophrya, 68.
Podophryidae, 67.
podura (Ichthydium), 244.
pogoniae (Microcotyle),

177.

Polian vesicles, 617.
polii (Chiton), 486.
politum (Liobunum), 412.
pollicaris (Pagurus), 394.
Pollicipes, 360.
Polyarthra, 237.
Polycera, 501. *

Polyceridae, 501.
Polychaeta, 282.
Polychcerus, 160.
Polycirrus, 296.
Polycladida, 169.
Polyclinidae, 670.
Polycystididae, 163.
Polydesmidae, 471.
Polydesmus, 471.
Polydora, 293.
Polygordidae, 280.
Polygordius, 281.
Polygyra, 520.
Polymastia, 79.
Polymastigida, 30.
Polymastiidae, 79.
polymerus (Mitella), 360.
polymorpha (Plumatella),

263.
polymorphus

(Echinococcus,) 202.
polymorphus (Stentor), 60.
Polynices, 537.
Polyp type of structure, 87.
Polyphemidae, 337.
Polyphemus, 338.
polyphemus (Limulus),

401.

Polypi, 3.
polypinum

(Carchesium), 66.
Polyplacophora, 484.
polypodia

(Dactylosphaerium), 16.
Polypodium, 92.
Polypus, 71.
Polystoma, 175.
Polystomidae, 175.
Polystominae, 175.
Polytoma, 36.
Polyxenidae, 472.
Polyxenus, 473.
Polyzoa, 245.
polyzonias

(Sertularella), 106.
Polyzoniidae, 468.
Polyzonium, 468.
pomatia (Helix), 519.
Pomatiopsis, 542.
pompilius (Nautilus), 606.

INDEX

729

pomum (Murex), 556.
ponderosum

(Campeloma), 544.
Pontellidae, 344.
Pontocypris, 355.
Pontoporeiidae, 368.
Porcellanasteridae, 627.
Porcellio, 379.
porcellus (Diurella), 241.
Porella, 258.
Porifera, 71.
Porites, 146.
porites (Porites), 146.
Poritidae, 146.
Pork tapeworm, 201.
Porocephalus, 457.
Porpita, 123.
portoricensis

(Spongodes), 135.
Portuguese man-of-war,

124.

Portunidae, 397.
postica (Theatops), 476.
Potamilla, 301.
poterium (Campanularia),

111.

Pottsiella, 262.
pratensis (Bryobia), 455.
pratensis (Galumna), 443.
Prawns, 386.
pretiosum (Dentalium),

491.

Priapulida, 276.
Priapulus, 276.
primitiva (Protamoaba), 15.
princeps (Architeuthis),

611.

princeps (Plumatella), 263.
priodonta (Asplanchna),

236.

Pristina, 309.
Proales, 238.
Probopyrus, 381.
proboscideum

(Porocephalus), 457.
Procerodes, 167.
Procerodidae, 167.
procurvus (Pleuroxus),

337.

producta (Eloactis), 142.
profunda (Polygyra), 521.
Proglottid, 189.
Progoneata, 465.
prolifer (Hybocodon), 102.
prolifera

(Acropora), 146.
prolifera (Epiactis), 143.
prolifera (Microciona), 84.
prompta (Epeira), 426.
Proneomenia, 484.
Proneomeniidae, 484.
Proneurotes, 211.

Pronocephalidae, 181.
Pronocephalus, 181.
Proostracon, 607.
propinqua (Bdelloura), 168.
propinquus (Cambarus),

392.

Propodium, 479.
Proporidae, 159.
Prorodon, 51.
Prosobranch gills, 529.
Prosobranchiata, 528.
Prosoma, 279.
Prosorhochmidae, 210.
Prosthiostomidae, 171.
Prosthiostomum, 171.
Prostomata, 181.
Prostomium, 277.
Protamoeba, 15.
protea (Aplysia), 499.
proteus (Amoeba), 16.
Protobranchiata, 567.
Protocnemes, 138.
Protohydra, 92.
Protomerite, 43.
Protonemertini, 205.
Protopodite, 326.
Protozoa, 11.
Protracheata, 462.
proxima (Nucula), 568.
pruinosa (Tubulipora),

251.

pruinosus

(Metoponorthus), 380.
Pseudocytheretta, 356.
pseudofelineus

(Amphimerus), 185.
Pseudolamellibranchiata,

573.

Pseudopodia, 11.
Pseudoscolex, 189.
Pseudoscorpionida, 408,

409.
Pseudostigmatic organ,

442.
psittacea (Rhynchonella),

268.

Psolus, 650.
psora (vEga), 375.
Psoroptes, 440.
Ptenoglossa, 535.
Pteraster, 630.
Pterasteridae, 630.
Pterocera, 549.
Pterodina, 239.
Pterodinidae, 239.
Pterodrilus, 306.
Pteropoda Gymnosomata,

499.
Pteropoda Thecosomata,

498.

Pterosagitta, 272.
Pterotracheidae, 552.

Ptilochcirus, 370.
Ptychobothriidae, 194.
Ptychodera, 654.
Ptychoderidae, 654.
pugilator (Uca),400.
pugilis (Strombus), 549.
pugnax (Uca), 400.
pulchella (Vallonia), 518.
pulchellus (Cyclops), 346.
pulcher (Trichorhynchus),

45.
pvilcherrima

(Branchiobdella), 305.
pulcherrima

(Predericella),262.
pulcherrima

(Holthuria), 649.
pulex (Daphnia), 335.
Pulmonata, 506.
Pulsating vacuole, 12.
pulvisculus

(Chlamydomonas), 36.
pumicosa (Cellepora), 259.
pumila (Sertularia), 106.
punctata (Cribrilina), 256.
punctata (Herpobdella),

321.

punctata (Nausithoe), 128.
punctata (Plumatella), 263.
punctatus (Octopus), 613.
punctifera

(Mallomonas), 35.
punctostriatus (Actseon),

496.

punctulata (Arbacia), 643.
Punctum, 523.
pupa (Enchelys), 51.
Pupilla, 515.
Pupillidae, 515.
Pupoides, 516.
Purple star, 632.
Purple sun-star, 630.
Purpura, 556.
pusilla (Natica), 538.
pusilla

(Scolopendrella), 466.
pusillus

(Dolichoglossus), 655.
pusillus

(Trichoniscus), 381.
pusiola

(Hippolyte), 387.
pustulata (Stylonychia),

63.

pustulosa (Quadrula), 584.
Pycnogonida, 458.
Pycnogonidae, 459.
Pycnogonum, 459.
pygmaea (Neptunea), 558.
pygmamm (Punctum), 523.
pygmaeus (Dinophilus),

280.

730

INDEX

pyramidata (Lingula), 267.
Pyramidellidae, 553.
Pyramidula, 522.
Pyrenoids, 31.
pyri (Eriophyes), 438.
pyriformis (Cynthia), 666.
pyriformis (Difflugia), 17.
Pyrosoma, 671.
Pyrosoma, 47.
pyrum (Phacus), 32.
Pyxidium, 66.

QUADRANGULARIS (Alona),

337.

quadrans (Astarte), 577.
quadra ta (Philine), 498.
quadricornis

(Lucernaria), 127.
quadricornis (Noteus),

240.
quadridens

(Monostaechas), 109.
quadridentatum

(Sphaeroma), 375.
quadripartita

(Tokophrya),69.
quadripes (Eriophyes), 439.
quadrispinosa

(Diastylis),384.
Quadruella, 18.
Quadrula, 583.
quadrumanus

(Chiropsalmus), 129.
Quahog, 590.
quaternarium

(^Eolosoma), 305.
quaternarium

(Spondylomorum), 36.
quinquecirrha

(Dactylometra), 130.
quinquiesperforata

(Mellita),645.

BABIDA (Lycosa), 433.
Rachiglossa, 554.
Rachis, 137.
Radial canal, 616.
Radial shields, 634.
Radials, 619.

radians (Dendrosoma), 69.
radians (Siderastrea), 149.
Radiata, 3, 4, 70.
radiata (Lampsilis), 579.
radiata

(Lerneaenicus), 351.
radicola (Ileterodera), 217.
radicula (Vermetus), 548.
Radiolaria, 24.
radiosa (Amoeba), 16.
radiosa (Epiclintes), 61.
radiosum

(Dactylosphserium), 16.

Radius, 614.

Radula, 480.

ramosa (Pyxidium), 66.

ramosum (Eudendrium),

99.
ranae

(Echinorhynchus), 229.
ranarum (Opalina), 57.
rangi (Holopus), 621.
rapax (Caligus), 349.
rapax (Piscicola), 317.
Raphidiophrys, 23.
rapifornis (Paractis), 143.
Rathkea, 98.
rathkei (Porcellio), 379.
Rattulidae, 241.
Rattulus, 241.
raveneli (Branchellion),

318.

Ray, 614.
Razor clams, 595.
recta (Lampsilis), 580.
Red abalone, 532.
Red coral, 135.
Red spiders, 454.
reflexa (Lyrnnsea), 509.
refuscens

(Dictyocaulus), 222.
regina (Fredericella), 262.
regulosus (Nothrus), 443.
relicta (Mysis), 383.
renale (Dioctophyme), 222.
rencapite

(Pronocephalus), 181.
Reniera, 83.
Renifer, 185.
reniformis (Potamilla),

301.

reniformis (Renilla), 138.
Renilla, 138.
Renillidae, 138.
repanda (Doris), 502.
Respiratory tree, 646.
Reticulariida, 19.
reticulata (Cancellaria),

563.
reticulata (Ceriodaphnia),

335.
reticulata (Limnicythere)

357.

reticulatus (Oreaster), 628.
Retusa, 496.
retusa (Succinea), 519.
Rhabdites, 157.
Rhabditis, 217.
Rhabdocoela, 160.
Rhabdocoalida, 160.
Rhabdostyla, 66.
rhadodactyla

(Pleurobrachia), 152.
Rhagon type of sponge, 72.
Rhegmatodes, 116.

Rhinophore, 495.
Rhipidoglossa, 530.
Rhizocephala, 362.
Rhizocrinus, 621.
Rhizogeton, 95.
Rhizoglyphus, 442.
Rhizomastigidae, 26.
Rhizomolgula, 665.
Rhizopoda, 14.
Rhizostomae, 131.
Rhizota, 232.
rhomboides ( Lepidoderma ) ,

243.

Rhopalia, 126.
Rhopalodina, 646.
Rhopilema, 131.
Rhynchobdellida, 317.
rhyncoboli (Doliocystis),

45.

Rhyncobolus, 291.
Rhynchobothriidae, 203.
Rhynchobothrius, 203.
Rhynchodemidae, 169.
Rhynchodemus, 169.
Rhyncholophidae, 454.
Rhyncholophus, 454.
Rhynchonella, 268.
Rhynchonellidae, 268.
Rhynchoscolex, 161.
Rice shell, 560.
ricinus (Ixodes), 446.
Ring canal, 616.
ringens (Melicerta), 233.
riparia (Argiope), 425.
riparia (Diplocardia), 312.
Rissoa, 541.
Rissoidae, 541.
ritteri (Rhizomolgula),

665.

rivalis (Diplogaster), 217.
River limpets, 513.
rivularis (Ancylus), 513.
rlvulosa (Nais), 308.
robusta (Idothea), 376.
robusta (Ophiura), 636.
robusta (Polymastia), 79.
robustum

(Tetrarhynchobothrium) ,

203.

robustus (Gordius), 227.
robustus (Scaloplos), 292.
Rock barnacles, 361.
Rock crab, 396.
roesseli (Stentor), 60.
rosacea (Diphasia), 107.
rosalbum (Polyzonium),

468.

rosea (Eisenia), 313.
rosea (Euglandina), 524.
roseola (Beroe), 154.
roseola (Leptosynapta),

651.

INDEX

731

roseola (Philodlna), 235.

Rossia, 609.

rostra turn (Loxophyllum),

53.

Rostellum, 189.
Rostrum, in Cephalopoda,

607 ; in Crustacea, 382 ;

in Acarina, 436.
Rotifer, 235.
Rotifera, 230.
Round clam, 590.
Round-web spiders, 424.
Round worms, 213.
rubellus (Lumbricus), 313.
rubens (Brachionus), 240.
rubens (Geophilus), 474.
rubens (Zygeupolia), 208.
ruber (Hydryphantes), 449.
ruber (Lineus), 207.
ruber (Linotaenia), 474.
ruber (Plakopus), 16.
ruber (Trachelas), 430.
ruber (Trachydermon),

488.

rubiginosa (Quadrula), 584.
rubra (Boltenia), 667.
rubra (Lepraa), 296.
rubra (Thyone), 649.
rubrum (Corallium), 135.
rubrum (Stichostemma),

212.

rudis (Littorina), 540.
rufescens (Dictyophyme),

222.

rufescens (Haliotis), 532.
rugosa (Alasmidonta), 582.
rugosa (Glossiphonia), 319.
rugosa (Sertularella), 106.
rugosa (Stomatoca), 98.
rugosum (Abothrium), 195.
runcinata (Salpa), 662.
ryderi (Heteromeyenia),

81.
ryderi (Microhydra), 119.

SABELLA, 300.
Sabellaria, 303.
Sabellidae, 300.
Sabelliformia, 300.
saccatus (Drassus), 419.
Sacculina, 363.
Sagartia, 144.
Sagartiidae, 144.
saginata (Taenia), 200.
Sagitta, 272.

salmoni (Davainea), 200.
salmonis (Discocotyle),

176.

Salpa, 661.
salparum (Trichophrys),

69.
Salpingoeca, 29.

salpinx (Haliclystus), 127.

Salticus, 435.

saltitans (Dasydytes), 244.

Salt-water mites, 453.

Salve bug, 375.

sanborni (Chelanops), 410.

Sand bug, 393.

Sand collar, 537.

Sand crab, 399.

Sand dollar, 644.

sanguinea (Marphysa),

290.
sanguineus

(Diaptomus),344.
sanguineus

(Enplobranchus), 296.
sanguinolenta

(Henricia), 629.
sapidus (Callinectes), 398.
sapotilla (Yoldia), 569.
Sarcocystis, 48.
Sarcodina, 14.
Sarcoptes, 440.
Sarcoptidae, 439.
Sarcosporidiida, 48.
sarsi (Ophiura), 636.
Sarsia, 96.
Sarsiella, 357.

savignyi (Leptochela), 374.
Saxicava, 596.
Saxicavidae, 596.
sayi (Panopeus), 397.
sayi (Physa),511.
Scab mite, 440.
gcaber (Porcellio), 380.
scabiei (Sarcoptes), 440.
Scalaria, 535.
Scalariidae, 535.
Scallops, 575.
Scalpellum, 359.
Scaphandridae, 497.
Scapholeberis, 335.
Scaphopoda, 490.
scapularis (Ixodes), 446.
Scaridium, 240.
Scavenger mites, 443.
scenicus (Salticus), 435.
schachti (Heterodera), 217.
Schistocephalus, 193.
Schistosoma, 187.
Schizonemertea, 207.
Schizopoda, 382.
Schizoporella, 257.
Schizotricha, 109.
schlosseri (Botryllus), 669.
Scleroblasts, 73.
Scoleciformia, 298.
Scolecolepis, 293.
Scolex, 189.
Scolopendra, 475.
Scolopendrella, 466.
Scolopendrellidae, 465.

Scolopendridae, 474.
Scoloplos, 292.
Scolopocryptops, 476.
Scorpionida, 404.
Scorpionidae, 405.
Scutellidae, 644.
Scutibranchiata, 529.
Scutigera, 477.
scutigera (Salpa), 662.
Scutigerella, 465.
Scutigeridae, 477.
Scutovertex, 443.
scutulata (Lycosa), 433.
Scutum, in cirripeds, 360;

in ticks, 445.
Scyllaea, 500.
Scyllseidae, 500.
Scyphistoma, 125.
Scyphomedusae, 125.
Scyphozoa, 125.
Scytonotus, 472.
Sea-anemones, 139.
Sea arrows, 610.
Sea beef, 486.
Sea cucumbers, 646.
Sea-fans, 136.
Sea feathers, 137.
Sea-fir, 107.
Sea hares, 499.
Sea-lilies, 619.
Sea mouse, 284.
Sea peach, 666.
Sea pens, 138.
Sea polyp, 613.
Sea pork, 670.
Sea potato, 667.
Sea-slugs, 500.
Sea spiders, 458.
Sea-urchins, 638.
.Sea whips, 135.
Secondary flagellum, 363.
secunda

(Stichotricha),61.
sedentaria (Phronima),

366.

Segmentina, 513.
Semaeostomeae, 129.
Semelidae, 589.
seminuda (Odostomia), 554.
senegalensis (Luidia), 627.
senta (Hydatina), 237.
Sepia, 608.
Sepiidae, 608.
Sepiolidae, 608.
Sepiophora, 608.
Septa, 145.
septentrionalis

(Terebratulina), 269.
Septibranchiata, 601.
Sergiolus, 419.
sericeum (Trombidium),

454.

732

INDEX

serpentina (Pristina), 309.

Serpulidae, 302.

serrata (Taenia), 201.

serratus (Polydesmus), 471.

serratus (Polydesmus), 472.

Serripes, 593.

Serrula, 409.

serrulatus (Cyclops), 347.

serrulatus

(Simocephalus), 335.
Sertularella, 106.
Sertularia, 106.
sertularia (Dinobryon), 35.
Sertulariidae, 105.
setacaudatus

(Tortanus),345.
Setae, 277.

setifera (Latona), 334.
setiferus (Peneus), 388.
setigera (Uronychia), 64.
setigerum (Loxophyllum),

53.

setosa (Ampharete), 296.
setosa (Spio), 293.
setosum (Diadema), 643.
sexpunctatus (Dolomedes),

432.
sexspinosa

(Scolopocryptops), 476.
Sheep's wool sponge, 85.
Ship worms, 598.
Shrimps, 386.
sicula (Appendicularia),

658.

Sida, 333.
Siderastrea, 149.
siderea (Siderastrea), 149.
Sididae, 333.
Sigaretus, 538.
sigismundi (Echiniscus),

458.

sigmoides (Metopus), 58.
Sigmurethra, 514.
signatus (Cyclops), 347.
sigsbei (Phormosoma), 642.
Siliqua, 595.

siliqua (Cyrtodaria), 597.
similis (Oithona), 347.
similoplexus

(Pneumonceces), 186.
Simocephalus, 335.
simplex (Anomia), 570.
simplex (Mastigamceba),

27.

simplex (Nuclearia), 22.
simplex (Rhyncholophus),

454.
simplex (Rhynchoscoltx),

161.
simplissima (Planaria),

166.
sincera (Valvata), 545.

Single-celled Animals, 11.
sinuosa (Meandrina), 149.
Siphon, In cephalopods,

602; in gastropods, 492,

529 ; in pelecypods, 563 ;

in tunicates, 663.
Siphonal canal, 529.
Siphonodentaliidae, 491.
Siphonodentalium, 492.
Siphonoglyph, 132.
Siphonophora, 121.
Siphonosoma, 274.
Siphonozooids, 137.
Siphuncle, 605.
Sipunculida, 273.
Sipunculoidea, 272.
sipunculoides

(Edwardsiella),140.
Sipunculus, 274.
siro (Tyroglyphus), 442.
Six-hooked embryo, 190.
Skenea, 543.
Skeneidae, 543.
Sleeping sickness, 30.
Slime sponges, 86.
Slipper-animalcules, 56.
Slugs, 526, 527, 528.
Sluiteri (Proneomenia),

484.

Small spider crab, 396.
Smittina, 258.
Snails, 492.
Snout mites, 453.
socialis (Enchytraeus), 307.
socialis (Lacinularia), 234.
socialis (Lineus), 208.
sociatus (Zoanthus), 141.
Soft-shell clam, 594.
sol (Actinophrys), 22.
Solaster, 630.
Solasteridae, 630.
Solemya, 569.
Solemyidae, 569.
Solenidae, 595.
Solenogastres, 483.
Solcnomya, 569.
Solifugae, 408.
solitaria (Haminea), 497.
solitaria ( Py ramidula ) ,

522.

solium (Tsenia),201.
solidissima (Mactra), 589.
Solpugida, 408.
Solpugidae, 408.
solstitialis

(Trochosphsera) , 236.
Somatogyrus, 542.
sordida (Proales), 238.
Sow-bugs, 378.
sowerbi (Craspedacusta),

119.
spadicea (Cyprsea), 550.

Sparganophilus, 312.
Spatangidae, 645.
Spatangoida, 645.
speciosa (Manayunkia),

301.
spectabilis (Tubularia),

103.
Sperm sac (in Oligochaeta),

303.
Spermatheca, in Oligochaeta,

303; in gastropods, 519.
sphaericus (Paratigastes),

348.

Sphaeridia, 639.
Sphaerium, 586.
Sphaeroma, 375.
Sphaeromidae, 375.
Sphaerophrya, 67.
sphaerula (Theridula), 421.
Sphaerularia, 217.
sphericus (Chydorus), 337.
Sphyranura, 176.
Spicules of sponges, 73.
Spider crabs, 395.
Spider webs, 415.
Spiders, 413.
Spindle muscle, 273.
spinea (Acrosoma), 426.
Spinnerets, 414.
spinosa (Childia), 159.
spinosus (Eurypauropus),

467.

Spintharus, 421.
Spinulosa, 628.
spinulosa (Fiona), 451.
spinulosus (Echinaster),

630.

Spiny lobsters, 392.
Spiny rock shell, 555.
Spio, 293.
Spionidae, 292.
Spioniformia, 292.
Spiracle, 403.
Spiral staircases, 535.
spiralis (Cirripathes), 139.
spiralis (Trichinella), 221.
Spire (in snail shells), 506.
Spirobolus, 470.
Spirocheta, 26.
Spirochetida, 26.
Spirochetidae, 26.
Spirorbis, 302.
spirorbis (Spirorbis), 302.
Spirostomum, 58.
Spirula, 607.
Spirulidae, 607.
Spisula, 589.
spitzbergensis

(Terebratella),269.
Spondylomorum, 36.
spongeliformis

(Cacospongia), 85.

INDEX

733

Sponges, 71.
Spongiaria, 71.
Spongidae, 84.
Spongilla, 81.
Spongiilidae, 80.
Spongin, 72.
Spongioblasts, 73.
Spongodes, 135.
Sporont, 43.
Sporosac, 91.
Sporozoa, 42.
Spotted fever, 47.
Spotted fever tick, 447.
squama ta (Amphipholis),

637.
squama tus (Lepidonotus),

285.

squamosus (Chiton), 490.
Squids, 608.
Squilla, 383.
stagnalis (Glossiphonia),

319.

stagnalis (Lymnsea), 509.
stamineum (Sphaerium),

586.

Starfish, 623.
Statoblast, 249.
Stauromedusae, 126.
Stauronereis, 291.
Steatoda, 420.
steenstrupi (Myxicola),

301.

steini (Colacium), 32.
steini (Salpingoeca), 29.
Stella (Bunodes), 143.
stellata (Acanthodoris),

502.
stellatum ( Amaroucium) ,

670.
stelleri (Cryptochiton),

489.

stenolepis (Mysis), 383.
Stenophora, 44.
Stenostomum, 161.
Stentor, 59.
Stentoridae, 59.
Stephanoceros, 233.
Stephanochasmus, 184.
Stephanops, 240.
Stephanosphaera, 37.
stercoralis (Strongyloides),

218.
Sternum, in scorpions, 405 ;

in spiders, 414.
Sthenelais, 285.
Stichaster, 631.
Stichasteridae, 631.
Stichocotyle, 178.
Stichostemma, 212.
Stichotricha, 61.
stiedae (Eimeria), 46.
Stigmal plate, 444.

Stilifer, 494.

stimpsoni (Callianassa),

389.

stimpsoni (Stylifer), 553.
stolli (Thyas),450.
Stolonifera, 134.
Stoloteuthis, 608.
Stomatopoda, 383.
Stomolophus, 131.
Stomotoca, 98.
Stone canal, 616.
Stony corals, 145.
strangulata (Dipurena), 96.
Streptoneura, 528.
Streptoneurous gastropods,

493.
stria tinum (Sphaerium),

586.

striatum (Crucibulum),539.
Strigea, 188.
strix (Epeira),425.
Strobila, in Scyphomedsae,

125 ; in Cestodes, 189.
Strobilops, 517.
strombi (Phascolion), 276.
Strombidae, 548.
Strombidium, 60.
Strombus, 548.
stromi (Nymphon), 461.
stromi (Scalpellum), 360.
stromi (Terebellides), 295.
Strongylidae, 221.
Strongylocentrotidae, 643.
Strongylocentrotus, 643.
Strongyloides, 218.
Strongylus, 223.
Strophitus, 581.
Study of Animals in Amer-

.ica, 5.
sturionis (Dichelestium),

350.

sturionis (Nitzschia), 174.
Styela, 666.

stygia (Caecidotea), 377.
Stylactis, 100.
Stylaria, 309.
Stylets, 204.
Stylifer, 553.
Stylochus, 170.
Stylommatophora, 514.
Stylonychia, 63.
Stylotella, 84.

subcarinata (Lioplax), 544.
Subchelate appendage, 363.
Subcuticula, 214.
subcylindricus

(Porocephalus), 457.
subdepressus (Clypeaster),

644.
Subdivisions of the Animal

Kingdom, 9.
suberea (Euplectella), 77.

Suberites, 79.
Suberitidae, 79.
Subgenital pockets, 126.
subglobosus

(Somatogyrus), 542.
sublata (Dictyna), 418.
sublevis (Lepidonotus),

285.

sublevis (Rossia), 609.
Submytilacea, 576.
Subneural gland, 660.
subsalsus (Limnodrilus),

311.
subsolidum (Campeloma),

544.

subulare (Pleurocera), 547.
Subumbrella, 88.
Succinea, 518.
Succineidae, 518.
Suctoria, 67.

sulcatum (Entosiphon), 34.
sulcatum (Sphaerium), 586.
Sulphur sponge, 80.
sulphurea (Ancula), 501.
sulphured (Cliona), 80.
sultana (Fredericella), 262.
Summer eggs, 329.
Sun-star, 630.
superba (Cynthia), 667.
supercillaris

(Bougainvillia),97.
suppressa (Gastrodonta),

526.

Supra-oral organs, 205.
Surra, 30.
Suture, 506.

swainsoni (Mitra),560.
Swimmeret, 363.
Swimming crabs, 397.
Sycon type of sponge, 72.
Syllidae, 286.
Syllis, 287.
gylvaticus

(Rhynchodemus), 169.
sylvestris (Amaurobius),

418.
symmetrica (Quadruella),

18.

Symphyla, 465.
Synapticula in Madrepora-

ria, 149; in Balanoglos-

sida, 654.
Synaptidae, 650.
Syncoelidium, 168.
Syncoryne, 96.
Synemosyna, 436.
Syngamus, 222.
Synura, 35.
syringa (Calycella), 112.

TABULAE, 145.
Tsenia, 200.

734

INDEX

Taenia coenurus, 202.
Tcenia echinococcus, 202.
Tceniarhynclms, 200.
Taeniidae, 200.
Tsenioglossa, 536.
taenioides (Linguatula),

457.

Tagelus, 596.
Talorchestia, 367.
talpoida (Hippa), 393.
tamesis (Spargamophilus),

312.

Tamoya, 129.
Tanaidae, 373.
Tanais, 373.
Tanystylum, 460.
Tape worms, 189.
Taphrocampa, 238.
Tarantula, 407.
Tarantulidae, 407.
Tardigrada, 457.
tardigradus (Rotifer), 235.
taylori (Leucandra), 77.
Tealia, 143.
Tectibranchiata, 496.
Teeth (in the radula), 480.
Tegenaria, 431.
Tegmentum, 484.
Teleoplacophora, 489.
Tellina, 588.
Tellinacea, 587.
Tellinidae, 587.
tellinoides ( Cumingia ) ,

589.

Telosporidia, 42.
Telson, 327, 363.
Temora, 342.
temporatus (Diplodiscus),

182.
tenebrosus (Dolomedes),

432.

tenella (Antedon), 622.
tenella (Ciona),667.
tenella (Schizotricha), 109.
tenella, Tellina, 588.
tenella (Tubularia), 103.
tenera (Asterias), 632.
tenera (Tellina), 588.
tenosperma (Carterius), 82.
tenta (Macoma), 588.
Tentaculata, 151.
tentaculata (Bythinia),

542.

Tentaculocysts, 126.
tenue (Eudendrium), 99.
tenuis (^Equorea), 116.
tenuis (Kowalevskia), 659.
tenuis (Lumbrinereis), 290.
tenuissimum (Trichosoma),

221.

tenuisulcata (Leda),569.
tepidariorum (Theridion),

422.

Terebellidae, 294.
Terebellides, 295.
Terebelliformia. 293.
Terebra, 561.
terebralis (Cerithiopsis),

546.

terebrans (Chelura), 372.
Terebratella, 269.
Terebratulidae, 268.
Terebratulina, 269.
Terebridae, 561.
Teredidae, 598.
Teredo, 598.

teres (Spirostomum), 58.
Terglpes, 505.
Tergum, 360.
termo (Oikomonas), 27.
ternata (Menipea), 253.
terrestris ( Lumbricus) ,

313.

Terricola, 168.
terricola (Rhabditis), 217.
Test (in sea-urchins), 638.
Testacea, 481.
Testacella, 524.
Testacellidae, 524.
Testicardines, 268.
testudinalis

(Acmaea), 530.
testudinaria

(Graptoleberis), 337.
testudo (Echiniscus), 458.
Tethya, 79.
Tethyidae, 79.
Tetrabranchiata, 605.
Tetractinellida, 78.
tetraedra (Eiseniella), 314.
Tetragnatha, 427.
Tetranychidae, 454.
Tetranychus, 455.
Tetraphyllidea, 195.
Tetrapneumones, 416.
Tetrarhynchobothrium,

203.

Tetrastemma, 212.
Tetrastemmidae, 211, 212.
texana (Scolopendrella),

466.

Texas cattle tick, 446.
Texas fever, 47.
Thalassarchna, 453.
Thalassema, 315.
Thalassicolla, 24.
Thalassicollidae, 24.
Thalassinidea, 388.
Thalia, 662.
Thaliacea, 660.
Thaumantiidae, 117.
Theatops, 475.
Theca, 145.
Thecosomata, 498.
Thelepus, 296.

Thelphusa fluviatilis, 394.
Thelyphonidae, 407.
Thenea, 78.
Theneidae, 78.
Therididae, 420.
Theridion, 422.
Theridula, 421.
TMnodrilus, 311.
Thomisidae, 427.
thompsoni ( Amphoriscus ) ,

77.

thompsoni (Teredo), 599.
Thoracica, 359.
Thoracostraca, 382.
Thorax, in arthropods, 323 ;

in ascidians, 668.
Thracia, 601.
thraciaef ormis ( Yoldia ) ,

569.

Threadworms, 214.
Thuiaria, 107.
thuja (Thuiaria), 107.
Thyas, 450.
Thyone, 649.

thyroides (Polygyra), 522.
Thysanosoma, 199.
tiarella (Pennaria), 101.
Tiaropsis, 114.
Tibellus, 429.
Ticks, 445.

Tiedemann's vesicles, 617.
tigris (Diurella),241.
Tima, 115.
tintinnabulum (Balanus),

362.

Tintinnidae, 60.
Tintinnopsis, 60.
Tintinnus, 60.
Tmarus, 428.
Toad crab, 395.
Tonicella, 487.
Tokophrya, 69.
tonsa (Acartia), 345.
Tooth papillae, 634.
Tornaria, 654.
Tornatina, 497.
Tornatinidae, 496.
torquata (Clyinenella), 299.
Tortanus, 344.
torva (Planaria),166.
Toxoglossa, 561.
Toxopneustes, 643.
Trachea, 403.
trachealis (Syngamus),

222.

Tracheata, 461.
Trachelas, 430.
Trachelinidae, 52.
Trachelocera, 52.
Trachelomonas, 32.
Trachomedusae, 117.
Trachydermon, 488.

INDEX

735

tranquilla (Trachelas),

430.
translucida (Gorgoderina),

186.

transversa (Area), 571.
transversa (Argiope), 425.
transversa (Terebratella),

269.

Trap-door spiders, 416.
tremaphoros (Carinoma),

207.

Trematodes, 171.
Trepang, 647, 648.
Treponema, 26.
Triarthridae, 237.
Triaxonia, 77.
tribuloides (Eucidaris),

642.

tricarinata (Valvata), 545.
Trichina, 221.
Trichinella, 221.
Trichinellidae, 220.
Trichinosis, 221.
trichiura (Trichuris), 220.
Trichocephalus dispar, 220.
Trichocyst, 48.
Trichodina, 65.
Trichodrilus, 311.
Trichoniscidae, 381.
Trichoniscus, 381.
trichophorum (Peranema),

33.

Trichophrya, 69.
Trichorhynchus, 44.
Trichosoma, 221.
trichota (Urostyla), 61.
Trichuris, 220.
Tricladida, 164.
tricolor (Adamsia), 144.
tricuspidata ( Sertularella ) ,

106.

Tridacna, 592.
tridentata (Polygyra), 521.
trifasciata (Argiope), 425.
triflda (Odostomia), 554.
trifolium (Epeira), 426.
Triforis, 546.

trigonum (Argyrodes), 421.
triguttatus (Xysticus),

428.
trilineata (Clidiophora),

600.

triloba (Edotea), 377.
Triops, 331.
Tripneustes, 643.
tripos (Ceratium),41.
tripus (Notommata), 238.
trispinosa (Cavolinia), 498.
trispinosa (Smittina), 258.
tristis (Chelanops),410.
Tristoma, 174.
Tristomidae, 173.

Tritia, 558.

tritici (Tylenchus),218.
Triton, 551.
Tritonidae, 551.
Tritonioidea, 500.
tritonis (Triton), 551.
Trivia, 550.

trivittata (Nassa),558.
trivolvis (Planorbis), 512.
Trochelminthes, 230.
Trochidae, 532.
Trochophore larva, 279.
Trochosa, 433.
Trochosphasra, 236.
Trochosphseridae, 236.
Trochus, 532.
Trombidiidae, 453.
Trombidium, 454.
Trophi, 231.
Trophonia, 300.
Trophosome, 90.
Trophozooid, 150.
truncata (Cyathomonas),

36.
truncata (Euglandina),

524.

truncata (Mya), 594.
truncata (Notommata),

238.

truncata (Pholas), 598.
truncatella (Bursaria), 59.
truncatus

(Cyathocephalus), 194.
trunculus (Murex),555.
tryoni (Ommastrephes),

610.

Trypanorhyncha, 202.
Trypanosoma, 30.
Trypanosomatida, 30.
Trypanosomidae, 30.
Tube foot, 616.
Tubella, 81.

tuberculatus (Chiton), 489.
tuberosa (Acineta), 68.
tuberosa (Cassia), 551.
Tubifex, 310.
tubifex (Tubifex), 310.
Tubificidae, 310.
Tubularia, 103.
Tubulariae, 93.
Tubulariidae, 103.
Tubulipora, 250.
Tubuliporidae, 250.
Tubulus marinus, 490.
tumida (Gastranella), 589.
Tunic (in Tunicata), 655.
Tunicata, 655.
tunicata (Katharina), 489.
Turbellaria, 157.
Turbinellidae, 559.
Turbinidae, 533.
Turbinoliidae, 147.

Turbo, 533.

turbo (Urocentrum), 55.
Turbonilla, 553.
turrita (Bugula), 254.
Turritella, 548.
Turritellidae, 547.
Turritopsis, 102.
Turtonia, 585.
Tylenchus, 218.
Typhloplana, 163.
Typhoplanidae, 162.
typicus (Centropages), 342.
Tyrean purple, 555.
Tyroglyphidae, 441.
Tyroglyphus, 442.

UCA, 399.
Ulmaridae, 130.
Uloboridae, 417.
TJloborus, 417.
umbellatum

(Codonocladium), 29.
Umbilicus (in snail shells),

492, 506.
Umbo, 564.
umbraticus (Geophilus),

474.

undata (Astarte), 577.
undata (Pisaurina), 432.
undatum (Buccinum), 558.
undulans (Blepharisma),

58.
undulata (Alasmidonta),

582.

undulata (Margarita), 533.
undulata (Quadrula), 584.
unguiculata (Linuche),

128.

ungulata (Cathypna), 241.
Unicola, 371.
unicornis (Conochilus),

234.
unicornis (Schizoporella),

257.

Unio, 583.
TJnionicola, 451.
Unionidae, 578.
Univalvia, 481.
urceolata (Difflugia), 17.
urceolata (Maldane), 298.
Urceolus, 33.
Urnatella, 247.
TJrnatellidae, 247.
Urocentridae, 55.
Urocentrum, 55.
Urochorda, 5.
Urochordata, 655.
Uroglena, 35.
Uroleptus, 62.
Uronema, 55.
Uronychia, 64.
Uropod, 373.

736

INDEX

Uropoda, 444.
Urosalpinx, 556.
Urostyla, 61.
TJrotricha, 51.
uva (Valkeria),261.
uvella (Synura),35.
uvellum (Polytoma), 37.

VACUOLE, (in Rotifers),

231.

vaga (Dero),309.
vagans (Biomyxa), 19.
valida ( Amphithoe) , 371.
Valkeria, 261.
Valkeriidae, 261.
Vallonia, 518.
Valloniidae, 518.
Valvata, 545.
Valvatidae, 544.
Vampyrella, 22.
vancouverensis

(Circinaria),524.
variabile

(Echeneibothrium), 197.
variabile (Pisidium), 587.
variabilis (Cittotaenia),

198.
variabilis (Dermacentor),

447.
variabilis (Leptoplana),

170.

varians ( Autolytus) , 287.
variegata (Strigea), 188.
variegata (Turritella), 548.
variegatus (Lytechinus),

643.
variegatus ( Sergiolus ) ,

420.

varius (Paragordius), 227.
vatia (Misumena), 428.
vegitans (Anthophysa), 28.
vegitans (Uropoda), 445.
Vejovidae, 405.
Vejovis, 405.
Velarium, 128.
Velella, 123.
Velellidae, 123.
Veliger larva, 481.
Velum, 88.

velum (Solemya),569.
Velutina, 538.
Velvet sponge, 85.
Veneracea, 590.
Venericardia, 577.
Veneridae, 590.
veneris (Cestum), 153.
ventricosa (Harpa), 561.
ventricosa (Lampsilis),

580.

ventricosa (Vertigo), 517.
yentricosum (Liobunum),

412.

Venus, 590.
Venus' girdle, 153.
venustum (^Eolosoma),

305.
venustus (Dermacentor),

447.

venustus (Julus),469.
Vermes, 155.
Vermetidae, 548.
Vermetus, 548.
Vermicular ia, 548.
vermicularis (Oxyuris),

225.
vermiculum

(Tetrastemma), 212.
vernalis (Branchipus), 330.
vernalis (Holosticha), 62.
verrilli (Halacarus), 453.
verrilli (Rhopilema), 131.
verrucaria (Lichenopora),

251.

verrucosa (Amoeba), 16.
verrucosa ( Mastigamoeba ) ,

27.

versicolor (Argulus), 352.
versicolor (Cyanea), 130.
versicolor (Ergasilus), 349.
versicolor (Xysticus), 428.
Vertebrata, 2, 5.
vertens (Gonionemus), 118.
verticillata

(Campanularia), 111.
verticillatum

(Calliobothrium),195.
Vertigo, 516.
vesicaudus

(Cephalogonimus), 186.
Vesicula seminalis, 303.
Vesiculariidae, 260.
vesicularis (Heterakis),

225.
vesicularis (Plumatella),

263.

Vesiculate sense organs, 89.
Vestibule, 246.
vestita (Amicula), 489.
vetulus (Simocephalus),

335.

vibex (Nassa),557.
Vibraculum, 249.
vidua (Cypridopsis),355.
villosa (Pelomyxa), 15.
vincta (Lacuna), 541.
Vinegar eel, 217.
Vinegar roan, 407.
Virbius, 387.
virens (Cypris), 354.
virens (Nereis), 288.
virescens (Zygonemertes),

211.
virgatum (Conchoderma),

361.

virgatus (Julus),469.
virginica (Ostrea), 574.
virginica (Goniobasis), 547.
virginiensis (Fontaria),

472.
viridata (Typhloplana),

163.

viridis (Cyclops), 346.
viridis (Ensis),595.
viridis (Euglena),32.
viridis (Eutreptia), 32.
viridis (Hydra), 92.
viridis (Laonice), 293.
viridis (Lineus), 207.
viridis (Perophora), 668.
viridis (Platygyra) , 149.
viridissima (Hydra), 92.
virilis (Cambarus), 392.
Visceral mass, 478.
vitis (Eriophyes), 439.
Vitrea, 525.

vitrea (Plumatella), 263.
vitreum (Anisonema), 33.
Vitrina, 525.
vittata (Philoscia),379.
vittatum (Liobunum), 412.
vittatum (Tetrastemma),

212.

vivax (Plasmodium),47.
vi vidus ( Cy stobranchus ) ,

318.

Vivipara, 544.
Viviparidae,543, 544.
volcano (Fissurella), 531.
volubilis (Campanularia),

111.

volupis (Dictyna), 418.
Volvocina, 37.
Volvox, 39.

volvox (Conochilus), 234.
Vortex, 162.
Vorticella, 65.
Vorticellidae, 64.
vulgare (Armadillidium),

380.

vulgare (Scalpellum), 360.
vulgaris (Arcella), 18.
vulgaris (Asterias), 632.
vulgaris (Crangon), 386.
vulgaris (Hydra), 92.
vulgaris (Palaemonetes),

387.
vulgaris (Phylodromus),

428.

vulgaris (Rotifer), 235.
vulgaris (Sabellaria), 303.

walcotti (Fredericella),

262.

Waldheimia, 269.
wardii (Mesostoma), 163.
warreni (Procerodes), 167.

INDEX

737

Water bears, 457.
Water fleas, 333.
Water mites, 447.
Watervascular system, 614.
Wentletraps, 535.
westermani

(Paragonimus), 184.
wheatlandi (Procerodes),

167.

Wheel animalcules, 230.
wheeleri (Bdelloura), 168.
wheeleri (Koenenia), 406.
Whelks, 558.
Whip scorpions, 407.
white! (Diplocentrus),406.
white! (Tarantula), 407.
wilsoni (Plagiostomum),

164.

Winter egg, in phyllopods,
329 ; in rotifers, 231.

Wolf spiders, 432.

wrzesniowskii (Lionotus),
53.

XlPHOSUEA, 400.

Xylotrya, 599.
Xysticus, 428.

YELLOW BACK, 580.
Yellow sponge, 85.
Yoldia, 568.

ypsilophora (Unionicola),
451.

ZANCLEA, 96.
Zilla, 426.
Zirphrca, 598.

Zoantharia, 138.
Zoantheae, 141.
Zoanthus, 141.
zonaria (Salpa), 662.
zonata (Limapontia), 506.
Zonitidae, 524.
Zonitoides, 525.
Zooaa, 394.
Zooecium, 245.
Zoophyta, 3, 4, 70, 89.
Zoothamnium, 66.
Zooxanthellae, 24.
zostericola (Sarsiella), 357.
zostericola (Virbius), 387.
Eygeupolia, 208.
Zygobranchiata, 530.
Zygodactyla, 116.
Zygonemertes, 211.