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TEXT-BOOK OF PALAEONTOLOGY

I

TEXT-HOOK

OF

PALAEONTOLOGY

BY

&*

KARL A\ VON ZITTEL

PROFESSOR OF GEOLOGY AM) 1'AI.AKOXTOLOGY IN THE UNIVERSITV dl MI'MCH

TRANSLATED AND EDITED BY

CHAELES B. EASTMAX, Ph.D.

ASSISTANT IX PALAEONTOLOGY IN THE MUSEUM OF COM PAR ATI\ K
AT HARVARD COI.I.KCK. CAMBRIDGE, MASS.

ENGLISH EDITION REVISED AND K.M.AK<;i;i> IJY THE AUTHOR AND EDITOR

IN COLLABORATION WITH THE FOLLOWING sl'Ki'l A LISTS :

C. K. BKECHKR, .1. M. CLARKE, \V. H. DALL, G. J. HINDE, A. HYATT, .1. S. KINGSLKV, H. A. l'II.-Hl:V
C. SCHUCHERT, S. H. SCUJJDKH, W. I'. sl.ADKX. K. ( ). I I.KK II. ( . \VA< H>MLTH

VOL. I. WITH 1476 WOODCUTS

iLontion
MACMILLAN AND CO., LTD.

NEW YORK: MACMILLAX & CO.
1900

EDITOR'S PREFACE

THE GninilrJiijc <lcr /'itliicutifiihf/ie, which forms the basis of the present work,
was published in the spring of 1895, only a short time after the completion
of the fifth and last volume of Professor von Zittel's celebrated ILunUnn-li ilcr
Palaeontologie. Of the latter, an excellent translation exists in French by
Barrels; but English-speaking students are without either an independent
treatise on Palaeontology or translation from any foreign work, which is
comparable in scope and character to the writings of von Zittel.

With the hope of supplying this deficiency the Editor undertook the task
of rendering the Gruwlziige into English. It was at first intended to bring
out a strictly literal translation, but with the Author's consent this plan was
modified in important respects which should be clearly understood by all.
The chapters on Protozoa and Coelenterata stand here essentially as in the
original, but nearly all the remaining chapters have been remodelled, enlarged,
and brought as nearly as possible up to date by a selected body of experts.

The greater part of the work is therefore a composite production, and
from the nature of the case some incongruities in style and treatment are to
be expected. For all the collaborators to have adhered to uniform limits of
alteration and expansion would have been impossible. It will be found,
therefore, that some portions of the revised text are not sensibly different
from the original while others are changed very radically, and a few chapters,
notably the MottiiMoidea, Mollusca, and Trilobites, are entirely rewritten. An
effort has been made throughout to adapt the text more especially to the
needs of Anglo-American students, and the bibliographies have been enlarged
with similar intent.

For all changes in the classification over the original .the revisers of the
different sections are responsible ; but although radical departures have been
made with the Author's sanction, one must by no means presume he is thereby
committed to all the innovations which are set forth. How far and whether
in all cases the system has been improved must be left for experience to
determine. The Author's graciousness, however, in yielding his own prefer-
ences on systematic points will be apparent on reading the subjoined preface.

Due acknowledgments are rendered the collaborators in the Author's

vi TEXT-BOOK OF PALAEONTOLOGY

preface, ami alsu in footnotes at the end of the several chapters. Their
names aiv enumerated In-low in tlie order of their respective sections, and the
Kditor begs to express at this time a sense of his profound appreciation of the
services that have been so generously remieieil. For the many personal
courtesies extended, he would return to each of them his sincere and hearty
thanks.

LIST OF COLLABORATORS

Mr. CHAKU-X WACHSMITII, i'n'in>iil,-<t, J!l«*tai'<l,;i.

Mi. \V. IV.R.'v SI.\I>KX. Asterozoa, !•:<•}, inozoa.

Dr. GEORGE JKXXIN«;S HIM.K, Vermcs.

Mi. KHWARD O. ULRICH, Bryozoa, OstntroJu.

Mr. CHAKI.KS SI'HIVIIKHT, Unichiopoda.

Dr. WILLIAM H. DALL, Pelecypoda.

Prof. HENRY A PILSBRY, Gastropoda.

Prof. Ai.i'in;rs HYATT, Cephalopoda.

Prof. CHARLES E. BEECHER, Trilobita.

Prof. JOHN M. CLARKE, Eucrustacea (pars), Acerata (par*).

Prof. JOHN S. KINGSLEY, Eucrustacea (pars), Acerata (pars).

Prof. SAMUEL H. SCUDDER, Insecta.

The Editor is also greatly indebted to his friend Dr. John C. Merriam,
who undertook the translation of the entire chapter on Mottu$ca, a very
laborious work. Dr. Merriam's assistance has been further enlisted in the
translation of the second volume, which will be devoted exclusively to the
Vertebrates. Dr. August F. Foerste was kind enough to furnish a transla-
tion of the chapter on Insects, and various friends have assisted in correcting
proofs. For the compilation of the index the Editor is indebted to Miss

Elizabeth B. Bryant, a former student of his at Radcliffe College, and to

lis brother, Mr. David P. Eastman.

CHARLES R. EASTMAN.

HAKVAI:I> UNIVKKSITY,
S.*litcmJbcr 15, 1899.

AUTHOR'S PREFACE

DIE englische Ausgabe meiner Grundziige der Palaeontologie hat ein vom
deutschen Original in verschiedener Hinsicht abweichende Gestalt erhalten.
Der Herausgeber, mein Freund und ehemaliger Schiller Dr. Eastman, suchte
mit meiner Zustimmung eine Anzahl der hervorragendsten Specialisten fur
die Bearbeitung einzelner Thierclassen zu gewinnen. Dadurch erfuhr das
Werk eine griindliche und sachkundige Ueberarbeitung, welche sich namentlich
im Detail vortheilhaft geltend macht und mancherlei Irrthiimer der deutschen
Ausgabe beseitigte. Fiir diese miihevolle und aufopfernde Arbeit bin ich den
Mitarbeitern des TEXT-BOOK zu grossem Dank verpflichtet.

Allerdings wurde durch die Betheiligung einer grosseren Anzahl von
Autoren, deren Anschauungen in systematischen Fragen nicht immer unter
einander und mit denen des Autors der deutschen Ausgabe in Einklang standen,
die Einheitlichkeit des \\7erkes nicht unerheblich gestort und auch der ursprung-
liche Umfang verschiedener Abschnitte bedeutend iiberschritten ; allein diese
Nachtheile diirften durch die sorgfaltigere Durcharbeitung des eigentlichen
Stoffes reichlich ausgeglichen sein.

Die Revision der Crinoideen hatte der verstorbene Herr Charles Waclismuth,
jene der Asteroideen und Echinoideen Herr W. Percy Sladen iibernomnien.
Abgesehen von einigen Abanderungen, welche mehr terminologische als
sachliche Fragen betreffen, wurde in diesen Abtheilungen eine weit voll-
standigere Aufzahlung und Characterisierung der fossilen Gattungen durch-
gefiihrt, als in der deutschen Ausgabe. Weitergehende Umgestaltung erfuhr
die Classe der Bryozooen durch Herrn E. 0. Ulrich. Die palaeozoischen Formen
sind von diesem ausgezeichneten Kenner mit einer Ausfiihrlichkeit behandelt,
welche nicht ganz mit der Darstelhmg ande.rer Abtheilungen in Einklang
steht. Auch die Transferierung der bereits bei den Korallen abgehandelten
Chaetetiden und Fistuliporiden zu den Bryozoen und die dadurch veranlasste
doppelte Darstellung derselben ist eine Incongruenz, welche sich nur durch die
Meinungsverschiedenheit iiber die zoologische Stellung dieser ausgestorbenen
Organismen Entschuldigung lasst.

Eine durchgreifende Umarbeitung haben die Brachiopoden durch Herrn
Charles Schuchert erfahren. Wahrend sich die deutsche Ausgabe mehr auf die

viii TKXT-linnK (>!•' 1'A LA K( >NT( >L< >< ;Y

\\ erke und AnsehauuniM'ii v<>n Thomas Davidson stiit/t, fol^t die rnglische
Uebersetzung sowohl in der AutYa>sun- do:- ( iati un.uen und Familim, als nueh
in den systematiselien Prineipien den iieust-n Arlieiten von James //"//, </. M.
('l"i']:i. und (', I-]. J.'rn-lirr. Die systeiuai isrheii I laupt uruppen sollen hier
zugleich entwicklungsgeschichtlichen Phaseu entsprerhen und das gauze
System den Anfordei un^en des bio^enet ischen ( Jrund^eset xes ^eniiuen. Von
ahnliclien Gesichtspunkteii \\urden aueli Professor l'>«j<'li< r bei der Bearbeitung
der Trilobitea und Professor Jlyiff bei jener der ('ep}ialoj)oden geleitet. Es
ist niir x\veifelliaft, ob die Zeit -/.\\ einer durchgreifenden Reform der bio-
logischen Systematik, bei welcher Avi'iiigi'r morphologische und vergleicbend-
anatomis. he Merkmale, als embryologische und phylogenetische Gesichtspimkte
im Vordergrund stehen, jetzt schon gekommen ist ; allein jedenfalls sucht die
in Nord America gegenwjirtig herrscbende Stromung auf einem neuen Weg
xur \Vahrheit zu gelangen und eine die genealogiscben Beziehungen deutlicher
wiederspiegelnde Systematik zu erzielen.

Bei den Pelecypoden hat Herr Dr. W. H. DaU die durch Neumayr eingefiihrten
und in den (Jrundziigen mit einigen Modificationeri angenommenen Gruppen
durch seine eigene, auf langjahrige Specialuntersuchungen basirte Eintheilung
eisetxt. Die Scaphopoden, Amphineuren, Gastropoden und Pteropoden
wurden von Herrn Professor H. A. Pilsbry, die Crustaceen mit Ausnahme der
Trilobiten und einiger anderer Gruppen von Professor /. S. Kingsky, und die
iibrigen Arthropoden von meinem langjahrigen Mitarbeiter und Freund
Professor X. //. ^ciiil/lcr in sachkundigster AVeise durchgesehen.

Fiir den wichtigen Abschnitt der Cephalopoden tragt Herr Professor
Alpheus JI//nff die A'erantwortlichkeit. Hier treten die Differenzen mit der
deutschen Ausgabe am aufFallendsten zu Tage, vertritt doch dieser Autor am
entschiedensten die moderne Richtung *.in America. Obwohl meine An-
schauungen iiber verschiedene Grundprincipien der Systematik, namentlich
iiber Al)grenzung von Familien, Gattungen und Arten von denen meines
amrrikanischen Collegen abweichen, so glaubte ich doch einem so hervorra-
genden Kenner der fossilen Cephalopoden bei der Bearbeitung des von ihm
ubernommen Al>schnittes vollig freie Hand lassen zu miissen. Das TEXT-
J)0(>K ist dadui'ch um eine werthvolle Originalarbeit bereichert worden, welche
\ iele bis jetxt noch nicht veriitfentlichte Thatsachen enthalt.

Xu i;an/. besonderem Dank bin ich dem Herausgeber der englischen
Aus-alie Hen n Dr. ('. /.'. Euxlnuin verpflichtet. Er hat keine Miihe gescheut,
da- \Yerk mil d<-n neiisten Krgebnissen der palaeontologischen Forschung in
Kinklan^; xu brin^en und den Fortgang derselben zu fordern.

DM. KARL A. VON ZITTEL.
Mi:N- H KN im September 1899.

CONTENTS

INTRODUCTION

PAGE

F DEFINITION AXD SCOPE OF PALAEONTOLOGY .... 1

SUB-KINGDOM I.

PKOTO/OA . . . . . . . . .17

SUB-KINGDOM II.
COELENTEEATA. (Zoophytes) - . . . . . .41

SUB-KINGDOM III.

ECHINODERMATA . . . . . . . .122

SUB-KINGDOM IV.

YKKMKS. (Worms) . . . . . . . .251

SUB-KINGDOM V.

MOLLUSCOIDEA . . . . . . . .257

SUB-KINGDOM VI.

MOLLUSCA . . . . . . . .344

I

SUB-KINGDOM VII.

ARTHROPODA. (Articulates) ...... 605

INDEX 693

INTRODUCTION

DEFINITION AND SCOPE OF PALAEONTOLOGY

Palaeontology (Aoyos ruv TraAcuwv e'l/Twv) is the science which treats of
the life which has existed on the globe during former geological periods. It
deals with all questions concerning the properties, classification, relationships,
descent, conditions of existence, and the distribution in space and time of the
ancient inhabitants of the earth, as well as with those theories of organic and
cosmogonic evolution which result from such inquiries.

By fossils, or petrifactions, are understood all remains or traces of plants
and animals which have lived before the beginning of the present geological
period, and have become preserved in the rocks. The evidence which is in
all cases conclusive as to the fossil character of organic remains is the
geological age of the formation in which they occur, whereas their mode and
state of preservation, or the fact of their belonging to extinct or to still living
species, are merely incidental considerations. Although, as a rule, fossils have
undergone more or less radical changes during the process of fossilisation, and
are usually converted into mineral substances, as the term petrifaction indi-
cates, nevertheless, under exceptionally favourable conditions (as in frozen
ground, amber, resin, peat, etc.), plants and animals may be preserved
through geological periods in a practically unaltered state. Carcasses of
mammoths and rhinoceroses entombed in the frozen mud-cliffs of Siberia, and
inclusions of insects, spiders, and plants, in amber are none the less genuine
fossils, in spite of their having sustained no trace whatever of mineral
infiltration.

A by no means inconsiderable number of plants and animals occurring
strictly fossil in Tertiary and Pleistocene formations belong to still living
species ; while, on the other hand, the remains of forms which have become
extinct during historical times (Bhytina, Alca, Didus, Pezophaps, etc.) can no
more be classed as fossils in the true sense of the word than all such recent
organisms as may chance to become buried in deposits now forming under the
present prevailing orographic and climatal conditions.

The changes which organic bodies undergo during the process of fossilisa-
tion are partly chemical and partly mechanical in their nature.1 According

1 M7///C, Charles A., Conditions of preservation of invertebrate fossils. Bull. U.S. Geol. and
Geog. Survey Territ., 1880, vol. V. p. 133.

Tmbucco, Oiac., La Petriflcazione. Pavia, 1887.

VOL. I B

ELEMENTS OF PALAEONTOLOGY

as certain portions of the original substance are removed, or are replaced atom
for atom by foreign matter, the result may be either carbonisation, decom-
position, total dissipation, or petrifaction.

Carbonisation is a deoxidising process taking place under water or with
limited access of air, and especially common among plants. Fossil wood and
other vegetable matter abound in peat, lignite, and bituminous coal, the
leaves being transformed into a thin flake of carbon, on which often the finest
venation is still discernible. In some cases chitinous animal structures also
become carbonised, as in insects, crustaceans, and graptolites.

Decomposition as a rule effectually destroys all organic carbon and nitrogen
compounds. With few exceptions, therefore, animals without hard parts,
such as worms, infusorians, naked mollusca, most hydrozoa, many anthozoa,
and the embryoes of vertebrates, leave no traces behind in the rocks. Horn,
hair, chitin, and similar structures are likewise totally destroyed during the
fossilisation process, while only under especially favourable conditions, as, for
instance, in ice or in frozen soil, muscular and epidermal tissues remain
unchanged ; or else, through the taking up of lime phosphate in argillaceous
and calcareous deposits, undergo a sort of petrifaction, in which the finer
structure is but little altered.1 Even the conservable hard parts of animal
bodies are deprived of their organic compounds ; bones give up their fats and
oils, and the shells of mollusks, echinoderms, and crustaceans lose their pig-
ments and soft substratum. The hard portions, which first become more or
less porous through loss of their organic constituents, next suffer the gradual
disintegration of their inorganic compounds, and experience lastly either total
dissolution, reabsorption, or petrifaction.

Petrifaction. — In this process foreign substances soluble in water (chiefly
calcium carbonate and silica, more rarely pyrites, iron oxyhydrate, and other
salts) impregnate and completely fill all original cavities as well as those
formed subsequently by decay. Chemical metamorphism takes place
occasionally, when, owing to the decomposition of certain inorganic con-
stituents, the original molecules become replaced by those of other substances.
For instance, we find quartz pseudomorphs after calcareous tests and
skeletons, and conversely, calcite pseudomorphs after silica, as in certain
sponges.

Wherever the space originally occupied by soft parts, as, for example, the
interior of a shell or other hollow body, becomes filled up with infiltrating
ooze, while the shell itself or the enclosing wall decays, there is produced a
cast of the interior, which in most cases (especially where the shell is thin, as in
ammonites, brachiopods, certain mollusks, and crustaceans) preserves an exact
copy of the original form, and is susceptible of as accurate determination as
the real object. Not infrequently fossil organisms leave molds or imprints of
their shells or skeletons — very rarely of their whole bodies — in the rocks.
Sometimes, indeed, their presence is indicated merely by tracks or footprints.

Fossils are often distorted by mechanical agencies, such as faulting, folding,
crushing, and other deformations of the country rock. Such cases require
especial attention, and due caution must be observed in their determination.

Palaeontology and Biology. — Although the fossil remains of ancient
life-forms yield but a fragmentary record of themselves, are almost never

1 Reis, Otto, Ueber Petrificirung der Muskulatur. Arch, mikroskop. Anat., Baud XLI.

INTRODUCTION 3

perfectly preserved, and are usually more or less altered in appearance, yet, on
the whole, they readily fit into place in the great framework of the zoological
and botanical classifications. Notwithstanding all their differences, they are
built on the same general plan as recent organisms, and their identification
requires the most careful comparison with nearly related plants and animals.
The methods of palaeontological research do not differ from those employed*
by the zoologist and botanist, excepting, of course, that the palaeontologist is
restricted to those parts alone which are capable of preservation, and must
reconstruct the missing soft parts ideally from analogy with recent forms. It
is, nevertheless, incumbent on the palaeontologist to obtain all possible informa-
tion from the material such as it is, aided by every means he can devise ; and
hence his investigations do not cease with an examination of the external,
macroscopic characteristics, but must be extended to the finer microscopic and
histological as well. In numerous subdivisions of the animal and vegetable
kingdoms, palaeontology has anticipated zoology and botany by important
histological discoveries ; in the branch of vertebrate comparative anatomy, for
example, through the exhaustive study of conservable hard parts, such as the
teeth, skeleton, dermal covering, etc., this science has been elevated to its present
high standard chiefly by palaeontologists (Cuvier, Owen, Huxley, H. v. Meyer,
Riitimeyer, Marsh, Cope, and others). The principle of correlation of parts, first
applied with such eminent success by Cuvier, according to which all parts of an
organism stand in certain fixed relationships to one another, so that one part
cannot vary without a corresponding variation taking place in the others, is
now worked out not only for the whole group of vertebrates, but for inverte-
brates as well ; and its elaboration is such that frequently a single bone, tooth,
or plate, a sadly demolished carapace, a shell-fragment, a bit of stem, and the
like, is sufficient for us to form a tolerably accurate conception of their former
owner. It is therefore clear that in so far as palaeontology has to deal with
the study and classification of fossil organisms, it is no other than a part of
zoology, comparative anatomy, and botany, and hence may be very properly
divided into Palaeozoology and Palaeobotany. Palaeontology has astonishingly
increased the subject-matter of the two biological sciences, has filled up in-
numerable gaps in the system, and has infinitely enriched our knowledge of the
variety and complexity of plant and animal organisation. In almost every class
of both kingdoms where preservation is possible, the number of fossil forms
considerably exceeds the recent. A natural classification of the Foraminifera,
sponges, corals, echinoderms, mollusks, vertebrates, and of the vascular crypto-
gams, cycads, and conifers, would be utterly inconceivable without taking
palaeontological evidence into account, since in certain classes (brachiopods,
cephalopocls, reptiles, mammals) the number of extinct fossil forms is ten, a
hundred, or even a thousand-fold greater than the living, and this proportion is
steadily increasing in favour of palaeontology, since new fossiliferous localities
are being discovered almost daily in various parts of the world.

Palaeontology and Geology. — Although as a biological science palaeon-
tology does not differ essentially from botany and zoology, yet its connection
with geology is none the less intimate, and consequently it has been cultivated
quite as assiduously by geologists as by biologists. The material is brought to
light almost wholly by geologists or by geological collectors, who derive it
from the stratified rocks of the earth's crust — that is to say, rocks which have been
formed by the subaqueous deposition of sediment, or have been built up from

4 ELEMENTS OF PALAEONTOLOGY

detritus on dry land by the agency of winds. The distribution of fossils
among stratified rocks is by no means promiscuous, and neither do all rocks
contain the same species ; but, on the contrary, each separate stratigraphical-
complex, and frequently even single beds and layers, are characterised by
certain particular suites of fossils. The older the rock, the more strikingly
different from recent organisms are its fossil remains ; the younger the forma-
tion, the greater is their resemblance. Now, since experience shows that
contemporaneous deposits which have been laid down under similar conditions
(as, for example, in salt or in fresh water) contain identical or at least very
similar fossils, the latter furnish us with an infallible guide, taken together
with the local stratigraphic succession, for determining the relative age of a
given formation. Furthermore, a knowledge of the fossils occurring in homo-
taxial deposits enables us to reconstruct the various palaeofaunas and palaeo-
floras which have existed on our planet at different periods in its history.
Having determined the chronological succession of the clastic rocks by means
of their superimposition and their characteristic or index-fossils, they may be
divided up into still smaller series, each one of which is characterised by a
particular assemblage of organic remains. In the main, then, palaeontology is
the ultimate foundation of historical geology.

Excluding the oldest metamorphic rocks (gneiss, mica schists, phyllite?,
etc.) which are destitute of fossils, and concerning whose origin there is still
great difference of opinion, the total thickness of the sedimentary rocks
amounts to 20,000 — 30,000 metres. The building up of this prodigious
pile of rock must have extended over an inconceivably long time, whose dura-
tion cannot even approximately be estimated, since we are without data as
to the rate of deposition in former periods, and since the beginning, culmina-
tion, and end of geological epochs cannot be correlated with astronomical
events.

Since, however, the earth has been inhabited in former times by very
different creatures from those now living ; since successive palaeofaunas and
palaeofloras follow one another everywhere in the same order ; and since,
furthermore, in certain formations the greater part or even the total number
of species appear and disappear in a body, so that one fauna or flora is
replaced almost in its entirety by the next following ; it is obvious that the
sedimentary rocks may be subdivided into a number of longer and shorter
time measures, which may be designated by particular names. The beginning
and end of such periods (group, system, or formation, series or section, stage,
zone, or bed) is usually indicated by local interruptions in the deposition,
occasioned by variations in sea-level, volcanic eruptions, or by other causes ;
and such disturbances are usually accompanied by changes in the flora and
fauna. The now generally accepted subdivision of the secondary rocks is
represented in the table on page 5, in which it should be noted that only the
first three columns are of universal significance, while the last two apply only
to European conditions.

The rocks of the Archaean Group amount to 40,000 — 60,000 metres in
thickness. They belong to the oldest and longest period in the history of
our planet, and are remarkable for their schistose and crystalline structure, as
well as for the total absence of fossils. In order of stratigraphy, gneiss com-
prises for the most part the oldest, mica, chlorite, and talc-schists the middle,
and phyllites (primitive schists) the youngest division of this group. The so-

INTRODUCTION

Eras

Periods

Epochs

0

Quarternary
System

Alluvium

I Deposits

Diluvium
(Pleistocene)

I'nst-larial S-nt-s
Glacial
I'nu'lacial ,,

Tertiary System

Pliocene

Sicilian Series (Sicilien)
Astian „ (Astien)

§ Miocene

Pontian Series fPontien)
Sannatian ,, (Sarmatien)
Tortonian „ (Tortonien)
Helvetian ,, (Helvetien)
Burdigalian Series (Burdigalien)

1JJ Oligocene

Aquitanian Series (Aquitanirn,)
Tmigrian „ (Tongrien)

pq — Eocene

o3

Ugimiin Series (Ligurien)
Bartouian ,, (Bartonien)
1'ari.sian „ (Lutetien)
Suessonian ,, (Suessonien)
Thanetian „ (Thanetien)

f
1

9

Cretaceous
System

Upper Cretaceous

Jianian Series (Danien)
Senonian ,, (Senonien)
Turonian ,, (Turonien)
Cenoinanian Series (Cenomanien)

Lower Cretaceous

Gault Series (Albien)
Aptian and Urgonian Series (Aptien, Urgonien)
Barremian Series (Barremien)
Neocomian ,, (Neocoinien)

Jurassic System

Upper Jurassic
(Malm)

Tithonian and Portland Series (Portlandien)
Kimineridgian ,, (Kiinnieridgien)
Oxfordian ,, (Oxfordien)
Kellaway ,, (Callovien)

Middle Jurassic
(Dogger)

Bath or Great Oolite Series (Bathoriien)
Bajeux or Inferior Oolite Series (Bajocien)

Lower Jurassic
(Lias)

Toarcian Series (Toarcien)
Charmouthian Series (Liasien)
Sinemurian ,, (Sinemurien)
Hettangian ,, (Hettangien)

Triassic System

Upper Triassic
(Keuper)

Rhaetic Series (Rhaetien)
Carniolan ,, (Carnien)
Norian ,, (Norieu)

Middle Triassic
(Muschelkalk)

Ladinian Series (Ladinien)
Virglorian „, (Virglorien)

Lower Triassic
(Bunter Sandstein)

Werfeniau Series (^^.

^

Permian System
(Dyas)

Zechstein
Rothliegendes

Thuringian Series (Thuringien)
Punjabian ,, (Punjabien)
Autunian ,, (Autunien)

Carboniferous
System

Coal Measures

Uralian Series (Uralien)
Muscovian ,, (Moscovien)

Carboniferous Limestone
(Culm)

Dinantian Series (Dinantien)

Devonian
System

Upper Devonian

Faniennian Series (Famennien)
Frasnian ,, (Frasnien)
Givetian „ (Givetien)

Middle Devonian

Eifelian Series (Eifelieu)

Lower Devonian

Coblenzian Series (Coblenzien)
Gedinnian „ (Gedinnien)

Silurian System

Silurian

Ludlow Series
Wenlock „ (Gothlandien)
Upper Llandovery Series

Ordovician
(Lower Silurian)

Bala or Caradoc Series
Llandello „ (Ordovicieu)
Arenig ,,

Cambrian
System

Upper Cambrian

FeS[o°gCSefS (Potsdaiaieu)

Middle Cambrian

Menevian Series (Acadien)

Lower Cambrian

Harlech Series (Georgien)

111

<< * o

Primitive Schist
System
Gneiss System

Phyllite (Primitive Schists,
Mica and Chlorite Schists,
etc.)
Gneiss

Precambrian Series (Algonkien)

6 ELEMENTS OF PALAEONTOLOGY

called fossil organism, JEozoon, occurring in gneiss, has been proved to be of
inorganic nature.

The Palaeozoic or Primary Group comprises the Cambrian. Ordovician,
Silurian, Devonian, Carboniferous, and Permian systems, each of which is
made up of a great number of series, stages, and zones. In the Cambrian
crustaceans (trilobites), mollusks and worms predominate, associated with a
few Pelmatozoa, coelenterates, sponges, and poorly preserved algae. In the
Silurian system all classes of the animal kingdom are represented with the
exception of amphibians, reptiles, birds, and mammals, while the flora still
consists of algae. Marine invertebrates are very abundant, especially crus-
taceans, mollusks, echinoderms, and coelenterates, while only a few frag-
mentary fish-remains indicate the presence of vertebrates. All the species,
and nearly all the genera, have since become extinct, and belong for the most
part to extinct families and orders. During the Devonian, Carboniferous, and
Permian systems, the same classes of animals continue as a body, but are
represented by totally different families and genera. Fishes develop a great,
variety of forms in the Devonian, amphibians (Stegocephalia) make their
appearance in the Carboniferous, and reptiles in the Permian. The flora con-
sists chiefly of vascular cryptogams, together with a few conifers and cycads.

The Mesozoic Group comprises three systems — the Triassic, Jurassic, and
Cretaceous. Many of the widely distributed Palaeozoic types (Tetracoralla,
Graptolites, Crinoids, Cystids, Blastoids, Brachiopods, Trilobites) have either wholly-
or in greater part disappeared, while others (Cephalopods, Lamellibranchs, Sea-
urchins) are replaced by very different genera and families. Vertebrates are
remarkable for the gigantic size attained by amphibians (Labyrinthodonta) and
many reptiles, as well as for the wonderful variety of the latter. Birds appear
for the first time in the Upper Jurassic (Arcliaeopteryx), and mammals towards
the close of the Triassic, being represented by diminutive, probably mar-
supial types. During the Triassic and Jurassic periods, vascular cryptogams,
conifers, and cycads remain the dominant plant forms, dicotyledons not occur-
ring until the middle Cretaceous.

The Cenozoic Group comprises the Tertiary and Post-Tertiary or Quaternary
systems. Among the invertebrates, ammonites, belemnites, Rudistae, and
most of the Crinoidea have now passed away. Amphibians and reptiles have
greatly declined, and, like the invertebrates, -are represented by still living
orders. On the other hand, birds, and most particularly mammals, attain a
wide distribution ; the latter class branches out in such manifold variety, and
experiences such rapid development during Cenozoic time, that it alone
furnishes us with the principal index-fossils of this era. From now on the
flora consists chiefly of dicotyledonous plants.

Palaeontology and Physical Geography. — Not only do fossils con-
stitute the very foundation of historical geology, but they furnish -us in
addition with invaluable information respecting the origin of the rocks in
which they occur, the former distribution of land and water, climatal
conditions, and the laws of geographical distribution that have prevailed in
former periods. By means of analogy with recent species we are able in
most cases readily to determine whether fossil forms pertain to land, fresh,
brackish, or salt water species, whence it is apparent under what conditions
the strata were deposited. The distribution of marine and fresh-water
formations helps us to certain conclusions respecting the extent of former

INTRODUCTION 7

seas and land areas. Deep-sea, shallow water, and littoral deposits are
readily distinguishable by means of their fossil organisms. By fossils, also,
even the climatal conditions of former periods are recorded with great
fidelity. The luxurious and uniform development of cryptogams over the
face of the globe during Carboniferous time presupposes a warm, moist
climate, little varying with latitude ; tropical dicotyledons occurring in the
Cretaceous and Tertiary deposits of Greenland, or coral-reefs extending into
high latitudes during the Palaeozoic era, prove with equal certainty the pre-
valence of a milder climate and higher oceanic temperature in earlier times ;
while again, the remains of reindeer, the lemming, musk-ox, polar fox, and
other arctic animals in the diluvium of Central Europe testify to a period of
glaciation with reduced mean annual temperature.

The geographical distribution of fossil organisms proves that the regions
and provinces occupied by recent plants and animals are to a certain extent
identical with those existing in the Tertiary, and that life has been subject to
the same distributional laws in the past as in the present. Nearly all recent
forms are the obvious descendants of extinct creatures which formerly
occupied the same region. For example, the fossil mammals, birds, and
reptiles of Diluvial time in Europe, Asia, Australia, North and South America,
are scarcely distinguishable from forms now inhabiting the same continents.
The old ancestral homes of marsupials and edentates were perpetuated in
Australia and South America until as recently as the Diluvial epoch, and
during the Tertiary, Europe, Asia, and America formed but a single zoological
province, inhabited by the ancestors of forms now living in the northern
hemisphere. An understanding of the physical conditions which have
governed the perpetuation of recent plants and animals in their respective
provinces (succession of similar types) would be utterly impossible without a
knowledge of their distribution in former times. In like manner, our know-
ledge of the distribution of land and water, of the climatal conditions, oceanic
currents, etc., of earlier periods depends chiefly upon evidence derived from
fossils.

Palaeontology and Embryology (Ontogeny). — To trace living plants
and animals through all stages of growth from the egg upward to maturity,
and thence on to final dissolution, is the task of Embryology or Ontogeny.
At the present moment, botanists and zoologists are devoting their most
scrutinising attention to embryological investigations, which latter accordingly
exert a powerful influence on the progress of biology, and particularly on the
classification. The fact that every individual, species, and genus of a whole
group of plants and animals passes through nearly the same course of
development, at least in the primary stages, and that all embryoes belonging
to a given order or class resemble one another so closely, up to a certain
stage, that they cannot be told apart, has revealed unexpected affinities among
forms differing very considerably in the adult stage. Cirripedes, for example,
which were formerly mistaken for shell-bearing mollusks, develop from the
same Nauplius-larvae as the Copepoda, Phyllopoda, and Ostracoda, although
the mature individuals belonging to these orders of crustaceans possess
but little common resemblance. Likewise, the whole group of vertebrate
embryoes can hardly be distinguished from one another in the earliest stages,
and only very gradually assume the characteristic features pertaining to class
and order.

8 ELEMENTS OF PALAEONTOLOGY

The results of embryological inquiry have a most important bearing on
palaeontology. Numerous fossil forms are known, which, in comparison
with recent related organisms, exhibit embryonic, or at least larval or adol-
escent characteristics. Examples of such persistent embryonic types are especi-
ally common in vertebrates, for the reason that here the skeleton becomes
ossified very early in life, and hence the immature stages of the recent can be
directly compared with adult fossil forms. Now, observation has shown that
in most of the older fossil fishes and reptiles, the vertebral column never
passed beyond an embryonic stage, but remained in a cartilaginous or
incompletely ossified condition through life. The Palaeozoic amphibians
(Stegocephalia) probably breathed by means of both gills and lungs through-
out life, whereas most recent amphibians lose their gills comparatively early
(Caducibranchia), and breathe wholly by lungs. Many fossil reptiles and
mammals retain certain skeletal peculiarities permanently, while allied recent
forms exhibit them only in embryonic stages. The construction and shape
of the skull in most of the older fossil reptiles and mammals closely corre-
sponds with that in embryoes of recent related types. In the oldest fossil
artiodactyls the palm-bones are all completely separated, while in recent
ruminants this division continues only during the embryonic stage, being
followed by a fusion of the two median metapodals, together with a reduction
of the laterals. Among invertebrates, also, fossil embryonic types are by no
means uncommon. The Palaeozoic Belinuridae find their counterpart in the
larvae of the common Limulus ; many fossil sea-urchins are characterised by
linear ambulacra, while recent related forms, although developing petaloid radii
in the adult stage, pass through the linear phase during adolescence. Many
fossil crinoids before maturity resemble the living genus Antedon ; and,
according to Jackson, recent oysters and Pectens exhibit in their nepionic
stages certain characters peculiar to Palaeozoic genera of mollusks.

The so-called fossil generalised or comprehensive types, which unite in one and
the same form characters which, in geologically later, or recent descendants,
have become distributed among different genera and families, are in reality
merely adolescent or immature types which have stopped short of the higher
differentiation attained by their descendants. Generalised types always
precede more highly specialised ; and properties that were originally distri-
butive among older forms are never reunited in geologically younger species
or genera. Trilobites, amphibians, and reptiles of the Palaeozoic and Mesozoic
eras, and early Tertiary mammals belong almost exclusively to the category
of generalised types.

In certain groups of vertebrates, and especially of mammals (Ungulata,
Carnivora), the chronological succession of genera is so closely paralleled by
the successive stages of development in the life-history of their descendants,
that to a certain extent the ontogeny of the individual is a representment of
a long chronological series of fossil forms. This truth furnishes a strong
foundation for the biogenetic law, enunciated in various terms by Geoffroy St.
Hilaire, Serres, Meckel, Fritz Miiller, and others, and recently more precisely
formulated by Haeckel, as follows : — The developmental history, or ontogeny of
an individual is merely a short and simplified repetition or recapitulation of
the slow (perhaps extending over thousands of years) process of evolution of
the species and of the whole branch.

The biogenetic law has since been found to hold true not only for verte-

INTRODUCTION 9

brates, but also for invertebrates, including even totally extinct types. In
ammonites, for instance, the primary or innermost whorls always differ from
the outer in their greater simplicity of suture, and in their lesser ornamenta-
tion. Very often a similarity is observable with geologically older forms ;
and it is a well-known fact that all ammonites pass through early stages which
resemble, at least so far as chambering of the shell is concerned, Palaeoxoi'-
goniatites. A comparison of the inner whorls of an ammonite with its corre-
sponding goniatitic form, or with older ammonites, seldom fails to reveal
ties of kinship not otherwise discernible. Beecher has shown that nearly
every stage in the growth of arm-supports in recent brachiopods corresponds
to some fossil genus ; and further, that the chronological succession of the
latter is to a certain degree identical with the successive ontogenetic stages
of recent forms.

The relation of so-called rudimentary organs occurring in recent forms to
those of the allied predecessors of the latter is of particular significance.
By rudimentary organs are meant certain structures (as, for example,
limbs, parts of limbs, organs of sense, respiration, digestion, reproduc-
tion, etc.), which are still indicated by dwarfed remains, but whose
physiological functions, and hence their utility to the organism, have wholly
disappeared. Rudimentary organs are, as a rule, either normally de-
veloped in an embryonic stage, or at least more strongly than in the adult
individual, owing to a process of degeneration, or retrogressive development.
The fossil progenitors of forms possessing rudimentary organs are almost
always characterised by a full development of the respective parts. The
lateral metacarpals and metatarsals in the horse and most ruminants, for
example, are indicated only by rudimentary side-splints ; but in an embryonic
stage they are much more strongly developed, and in related fossil forms they
occur as normal bones, carrying toes like the other metapodals, and serving
for locomotion and support. The wrist and metacarpal bones in birds have
also suffered degeneration, as is evident from a comparison with embryoes
and with older forms (Archaeopteryx), which exhibit a much higher develop-
ment. In like manner, the teeth of birds have also become degenerated. In
only a few forms (parrots) are indications of dental ridges discernible
during embryonic stages; but in all known Mesozoic birds the teeth are
well developed and remain functional throughout life. Similarly, teeth are
developed during embryonic stages in the baleen whale, but subsequently
become atrophied ; while in the older fossil Cetacea teeth are always present.
Other instances of this nature are to be met with in great profusion, both
among vertebrates and invertebrates.

The biogenetic law is, however, not infrequently obscured, for the reason
that two closely related forms may not develop in exactly the same manner ;
embryoes of the one type may be affected by peculiar accelerating impulses
which are not shared by those of the other, and in consequence the first may
pass through certain stages very rapidly, or may even omit them altogether.
In this way the historical or palingenetic record contained in the growth of
every individual may be to a large extent suppressed or rendered unintelligible;
and this phenomenon of inexact parallelism (coenogenesis) is especially common
in highly differentiated types, where the embryo passes through a multitude
of phases.

Palaeontology and Phylogeny. — While conceding that by means of

10 ELEMENTS OF PALAEONTOLOGY

embryological investigations zoologists and botanists are able to trace out the
gradual development and differentiation of an organism through all its various
stages, and thereupon to construct a tree of descent (phylogcny) founded upon
the successive phases of growth, nevertheless such hypothetical genealogies
can only be relied upon as truthful when they are substantiated by palaeonto-
logical facts. And only in cases where the different ontogenetic stages are
represented by corresponding fossil embryonic or generalised types, which
appear in the same chronological order, and clothe the supposititious ancestral
tree with real forms, can the truthfulness of the latter be said to have been
established. This requirement palaeontology is from the nature of things
unable to satisfy except in a few instances ; but a multitude of other facts,
however, testifies to the blood-kinship between morphologically similar fossil
and recent organisms, and points to the direct descent of the younger from the
older forms.

Geology proves conclusively that of the numerous floras and faunas which
lie buried in the rocks, those which are most nearly of the same geological
age bear the greatest resemblance to each other. It often happens that species
and genera occurring in a given formation reappear in the next following with
scarcely any perceptible changes, so that the doctrine of the gradual trans-
formation and transmutation of older forms is irresistibly forced upon one,
while the faunas and floras of later periods assert themselves as the obvious
descendants of the more ancient. Other weighty evidence for the progressive
evolution of organisms is afforded by fossil transitional series, of which a
considerable number are known to us, notwithstanding the imperfection of the
palaeontological record. By transitional 'series are meant a greater or lesser
number of similar forms occurring through several successive horizons, and
constituting a practically unbroken morphic chain. Oftentimes, indeed, the
differences between individuals belonging to different periods are so slight that
we can hardly assign to them the value of a variety. But let a number of
such mutations occur in succession, the end-members of the series become
finally so divergent as to constitute distinct species and genera. The most
striking and most numerous examples of transitional series naturally occur in
types peculiarly well fitted for preservation, such as mollusks, brachiopods,
sea-urchins, corals, and vertebrates. Particularly remarkable among mollusks
are the closely linked transitional series in ammonites. Among vertebrates
transmutation proceeded far more rapidly than among invertebrates, and
accordingly, the successive members of a series are usually so divergent as to
require their assignment to separate genera.

With increasing abundance of palaeontological material, the more numerous
and more complete are the series of intermediate forms which are brought to
light. But the more extended our knowledge of transitional series, the greater
is the difficulty we encounter in defining our conception of species. While the
older disciples of the Linnaean and Cuvierian' schools contended that each
individual species was created with a certain definite sum of fixed characters,
and remained incapable of any extensive modifications ; on the other hand,
those holding to the theory of descent, evolution, or transmutation, look
upon varieties, species, subgenera, genera, families, orders, classes, and sub-
kingdoms as distinctions of merely transient importance, corresponding to
the state of our information at the present time ; it being assumed that
by means of gradual transmutation during the course of ages all organisms

INTRODUCTION 11

have become evolved from a single primitive cell, or from a few primitive
types.

According to the Linne"-Cuvier doctrine, a species is composed of individuals
which are directly descended from one another, or from common ancestors,
and which resemble their progenitors as much as they resemble each other.
Members of one and the same species interbreed, while individuals belonging
to different species do not cross, or when they do, produce infertile or imper-
fectly fertile offspring.

According to the theory of descent, no sharp specific distinctions can be
drawn, but all individuals are assigned to the same species which possess a
number of essential properties in common, and which are not connected on
all sides with neighbouring groups by means of intermediate types. It is
plain that this definition is open to considerable laxity of interpretation, and
inasmuch as the direct descent of individuals belonging to a given species
cannot always (in palaeontology never) be determined on experimental grounds,
systematists are rarely fully agreed in regard to the limitations of species,
genera, and families.

The doctrine of the invariability of species received powerful support from
the cataclysmic theory of Cuvier, which maintained that each period in the
earth's history is marked by distinctively characteristic faunas and floras ; that
no species is common to two successive periods ; that tremendous convulsions
of nature (cataclysms} occurred at the close of each cycle, and annihilated the
whole organic world ; and that by means of special creative acts, the renovated
earth became time and again populated with new animals and plants which
bore • absolutely no connection either with previous or with subsequently
introduced types.

Cuvier's cataclysmic theory may be regarded at the present day as com-
pletely overthrown, inasmuch as the modern school of geology, following the
leadership of Sir Charles Lyell, has demonstrated conclusively that the earth
has proceeded from one stage to another during the course of its development
only with the utmost slowness ; that the same forces and laws which regulate
the world of to-day have operated likewise in primeval times ; and that geo-
logical periods are by no means abruptly set off from one another, but, on the
contrary, are linked together by innumerable transitional stages.

The theory of the descendant origin of organic forms, which was advanced
as early as 1802 by J. B. Lamarck and Geoffroy St. Hilaire, and was supported
by Gothe, Oken, and Meckel in Germany, kept winning continually more and
more adherents, yet it was not until the latter half of the present century that
its universal significance was insisted on by Charles Darwin and his school.

Palaeontology, as already remarked, contributes a great deal of extremely
weighty evidence in favour of the theory of descent ; the series of intermediate
forms, often traceable through several successive formations ; the presence of
embryonic and generalised types ; the parallelism between ontogeny and the
chronological succession of related fossil forms ; the similarity between floras
and faunas of approximately the same age ; the correspondence in the geo-
graphical distribution of recent organisms with that of their progenitors ; arid
a host of other facts are explicable only by means of the theory of descent.

The causes of variation and transmutation were attributed by Lamarck
chie,fly to the use and disuse of organs ; secondly, to the effect of changes in ex-
ternal conditions ; and lastly, to a supposed resident tendency toward variation

12 ELEMENTS OF PALAEONTOLOGY

and perfection existing in each individual. According to Lamarck, new
properties brought about by these influences are transmitted to descendants
through inheritance, and become permanently established in the race. Geoffroy
St. Hilaire maintained the same principles on the whole, but ascribed the chief
causes of variation of species to the influence of environment.

The Darwinian theory of natural selection is based upon the property
common to all organisms of acquiring ancestral characteristics through heredity,
and of transmitting them in turn to their progeny ; and also on the adapta-
bility of organisms to particular external conditions, by means of which
variations are brought about. Since in the struggle for existence only those
individuals which are the best adapted — that is to .say, those possessing the
most advantageous modifications — survive, nature is continually exercising,
according to Darwin, a most rigorous selection which operates toward the
increase and perfection of useful variations. Through the constant accumula-
tion of originally slight yet serviceable modifications, and through the perpetual
transmission of the same from one generation to another, there are produced
first different varieties, then species, and eventually genera, families, and orders.
The zoological and botanical classifications are, according to Darwin, merely an
expression of genealogical facts, exhibiting the remoter and closer ties of con-
sanguinity which exist among different organic forms.

Darwin's explanation of the origin of species through the agency of natural
selection found in Wallace, Huxley, Haeckel, and others, zealous and ingenious
supporters, while on other sides it encountered vehement opposition. M.
Wagner regarded free intercrossing as an insurmountable obstacle to the
establishment of new modifications, and contended that the isolation of a few
individuals, a condition which would occur most frequently during migrations,
was a necessary postulate in accounting for the origin of each new variety or
species. Bronn, Nageli, and A. Braun raised the objection to Darwin's theory
of natural selection that many organs are entirely useless to the individual,
and therefore natural selection, which depends upon the principle of utility,
could neither have produced such organs nor could have modified them in any
way. Nageli assumed that, in addition to natural selection, a certain resident
tendency toward perfection, inherent in every individual, takes part in con-
ditioning the growth of morphological characters. Every variation brought
about by external or internal agencies is at once in the nature of a differentia-
tion, a step forward in the division of labour, and consequently an advancement.

Weismann endeavoured in a similar manner to supplement Darwin's theory
of selection by his hypothesis of the continuity of germ-plasm. According to
Weismann, germ-matter is of itself capable of producing all variations that
are useful to an organism. Only that which exists in the original plasm or in
the sexual elements as embryonic rudiments can be transmitted to offspring
and become further acted upon and developed by natural selection, according
to Weismann's theory. The continuity, that is to say, the perpetual trans-
mission of a portion of the germ-plasm from parents to offspring, forms a
necessary postulate to the theory of descent. In opposition to Weismann,
who attributes only a subordinate influence to the action of physical environ-
ment as a cause of variations, and who particularly denies the inheritance of
acquired characters, stands the Neo-Lamarckian school (represented by Herbert
Spencer, Cope, Hyatt, Osborn, Semper, Glaus, Roux, and others), which ranges
itself more and more on the side of Lamarckian ideas, and ascribes to the use

INTRODUCTION 13

and disuse of organs, and to external conditions, a very considerable influence
in effecting the transmutation of organic forms. While, on the one hand,
Semper, Locard, and Clessin undertake to prove the direct action of environ-
ment on mollusks in a number of instances, and Schmankewitz confidently
asserts that the transformations in Artemia are induced by changes in the
saltness of the water; on the other hand, Cope, Osborn, Roux, and others*
emphasise the effect of use and disuse, and abundance or scantiness of food-
supply. Adequate nourishment and exercise increase the development of a
given organ, while physical conditions determine its form. Since like causes
produce like effects in the animate as well as in the inanimate world, it is
obvious that similar organs must be developed in a variety of plant and animal
forms wherever they are subjected to similar external conditions, and especially
to the same physical agencies. A convenient explanation is thus found for the
phenomena of parallelism, or recurring " common types of structure," which are
in nowise related to one another by inheritance. The analogous swimming-
organs of fishes, ichthyosaurians, and whales, or the analogous limb-structure
in long-legged ruminants, the horse, elephant, and carnivora, are due to
adaptation to external conditions and to use; the same explanation also
accounts for the like form of sternum in bats, birds, and Pterosauria, or for the
spindle-shaped body characteristic of most rapid-swimming fishes, reptiles, and
aquatic mammals, or for the similar form of jaw possessed by marsupials and
various orders of Placentalia. These are all instances of parallelism, in which
it often happens that two fundamentally different forms acquire the same
outward shape, or become provided with similar or analogous organs. Kineto-
genesis, or the process of a gradual transformation of parts, especially parts
belonging to the internal skeleton, skull, and limbs, is very ingeniously
interpreted by Cope as having been accomplished in mammals through the
agency of mechanical conditions, use, and food. The same author has also
traced out the different stages of development in fossil genera as exemplified
by numerous series of intermediate forms.

Life -Period and Extinction of Species. — Observation shows that
different organisms are by no means equally susceptible to impulses received
from the outer world. Many fossil genera remain almost wholly unchanged
throughout a number of formations (Foraminifera, Cidaris, Nautilus, Lingula,
Terebratula, Insectivora), and hence may be designated as persistent or conservative
types, in contradistinction to variable types. The latter pass through rapid changes
at the beginning of their career, develop a great variety of forms, and send out
branches and off-shoots in all directions up to a certain point ; they may then
die out after a comparatively short period of ascendency (Nummidites, Graptolites,
Cystids, Blastoids, Tetracoralla, Palechinoidea, Trilobitae, Eudistae, Ichthyosauria,
Pterosauria, Dinosauria, Amblypoda, Toxodontia, etc.), or in some cases may even
continue on to the present day with undiminished vitality (Spatangidae,
Clypeastridae, many "land and fresh-water mollusks, crabs, lizards, snakes,
ruminants, apes). Not infrequently types that were primitively variable pas&
over gradually into persistent ; their power of adaptation dwindles, they grow
less plastic, become incapable of sending off new varieties, species, or genera,
and as the less vigorous of their number become worsted one after another, they
finally stand out like curious, isolated relics of antiquity (Pentacrinus, Hatteria,
Tapirus, Equus, etc.) in the midst of subsequently remodelled surroundings.
A one-sided development in a certain direction, excessive size, abnormal

14 ELEMENTS OF PALAEONTOLOGY

(liyper-tropliic) peculiarities, or too high specialisation of organs, is as a rule
injurious to the form and leads usually to its extermination. Many groups
remarkable for their extreme differentiation (Dinosauria, Pterosauria, AmUypoda,
Toxodontia, etc.) have become extinct probably for this reason, since, having
advanced so far in a single limited direction, adaptation in other directions was
no longer possible.

Persistent types seldom produce a large number of species during a single
geological period ; types that start up suddenly and proceed to vary rapidly
as a rule soon die out ; while groups that develop slowly and steadily usually
contain in their growth the promise of great longevity.

For the extinction of many plants (Sigillaria, Lepidodendron, Filices) and
animals (Blastoids, Tetracomlla, Trilobites, Ammonites, Rudistae, Ichthyosauria, etc.)
of former periods no adequate explanation has as yet been found. Changes
in external conditions, especially such as regards the distribution of land and
water, climatal conditions, saltness of the water, volcanic eruptions, paucity of
food-supply, and the encroachments of natural enemies, may have led in many
instances to the extinction of certain forms, but such conjectures signally fail
to account for the disappearance of an entire species or particular group of
organisms. Oftentimes extinction seems to have been caused merely by
superannuation. Long-lived forms belong for the most part to persistent
types whose range of species is limited. Their reproductive functions have
declined, and like an individual in its dotage, they evince all the symptoms of
decrepitude and old age. Darwin attributes the extinction of less well-adapted
organisms to the struggle for existence ; but since, according to the theory of
natural selection, new species arise only with extreme slowness by means of
the gradual accumulation of useful variations, and since in like manner their
less successful competitors are only very gradually crowded out, we should
expect to find in the rocks, supposing that the palaeontological record were in
any degree perfect, all manner of extinct intermediate forms, and we should be
able, at least for those groups especially liable to conservation, to build up
complete ancestral trees. But as observation shows, not only do most plants
and animals now living in a wild state adhere to their peculiar characteristics
with great tenacity, exhibiting barely appreciable changes even in the course
of hundreds or thousands of years, but, furthermore, fossil species remain
within the limits of a single geological period fairly constant. With the
beginning of a new epoch or period, however, which is usually indicated in
the rocks by petrographical changes, a greater or lesser number of species
either entirely disappears, or is replaced by closely related, but at the same
time more or less different forms. Obviously, therefore, there have been
periods when the process of transformation and the weeding out of organisms
were greatly accelerated, and following upon these reconstructive periods long
intervals of repose have ensued, during which intervals species have adhered
to their characteristic forms with but little variation. The fact that evolution
has advanced by occasional bounds or leaps stands, however, in nowise contra-
dictory to the theory of descent.

The whole animate community at any point on the earth's surface rests
normally in a state of equilibrium, the balance being maintained by the con-
certed action of all ranks and members of society. For the preservation of
this balance nature practises a most rigid domestic economy. Every plant
depends upon particular conditions of soil, food, temperature, moisture, and

INTRODUCTION 15

other requisites for its support ; and these conditions govern its distribution
ami increase in the last degree. Every plant controls the destiny of all
animals subsisting upon it ; their numbers multiply with its increase, and
wane with its decrease. The fate of these creatures determines that of their
natural enemies, who stand in similar relationships to still remoter circles;
and hence no form can overstride the bounds set for it by the general balance
without disturbing the whole general system of economy. Let the flora or fauna
of a given region become altered by the extinction of a number of species, or
by the introduction of new and more powerful competitors, the balance is
immediately upset. In the first instance vacant places must be filled up, and
in the second, room must be made for the newcomers at the expense of the
settled community. Thus, wherever climatal, orographic, or other changes
are instrumental in bringing about the extermination of large numbers of
plants and animals during the lapse of a geological period, an inequilibrium
must necessarily result. But thereupon the struggle for existence is waged
with unwonted severity among the survivors, until finally a new state of
equilibrium is attained, and a pause in the formation of new species ensues.

The whole course of evolution in the organic world during past geological
periods indicates not only definite progression in all branches of the animal
and vegetable kingdoms up to their present state, but also an advance toward
perfection. Granting that the theory of descent is true, and that all organisms
have developed from a single primitive cell, or from a few primitive ground-
types, then every new growth and differentiation must stand for improvement
and progress, leading gradually to the development of more or less highly
specialised organs, and to a division of labour in their physiological functions ;
the higher the degree in which this is manifested, and the more conformably
to apparent purpose and utility that each organ fulfils its functions, the more
perfect is the organism, as we conventionally term it. Evolution in the
organic world has not advanced in a simple, straightforward direction, but in
an exceedingly complicated and circuitous. The biological systems, accord-
ingly, do not suggest to us the similitude of a ladder with its numerous
rounds, but rather that of an enormously ramifying tree, whose topmost
twigs represent the youngest, and, on the whole, the most perfect forms of
every branch. The root, trunk, and a goodly portion of the upper limbs lie
buried in the earth ; and only the ultimate green shoots, the last and most
highly differentiated members of long ancestral lines, blossom forth in the
world of to-day.1

1 [In connection with the two preceding topics, see a paper by the author, read before the Inter-
national Congress of Geologists, 1894, on " Palaeontology and the Biogenetic Law" (reprinted in
Natural Science, vol. VI., May 1895).

On the terminology of evolution in general, see A. Hyatt, " Bioplastology and the Belated
Branches of Biologic Research " (Proc. Bost. Soc. Nat. Hist, vol. XXVI., 1893). Abstract of same
in Zoolog. Anzeiger, No. 405, 1892. Other terms employed in the foregoing are introduced and
explained by Cope in his "Origin of the Fittest," 1887, and in various articles in the American
Naturalist.— TRANS.]

16

ELEMENTS OF PALAEONTOLOGY

OUTLINE CLASSIFICATION OF THE ANIMAL KINGDOM.

Sub-Kingdoms. Sub-Branches.

I. PROTOZOA

II. COELENTERATA

III. ECHINODERMATA

IV. VERMES

V. MOLLUSCOIDEA

VI. MOLLUSCA .

VII. ARTHROPODA

VIII. VERTEBRATA

I. Porifera .

II. Cnidaria .

I. Pelmatozoa

II. Asterozoa

III. Echinozoa

[. Branchiata

[. Tracheata

Classes.

1. Rhizopoda.

2. Flagellata.1

3. Infusoria.1

4. Gregarina.1

1. Spongiae.

'I. Anthozoa.

2. Hydrozoa.

[1. Crinoideal

2. Cystoidea.l

3. Blastoideci

:1. Ophiuroidea.

2. Aster oidea.

1. JSchinQidfid-

2. Holothurioidea.

1. Platyhelminthes.1

2. Nemathelminthes.

*3. Gephyrea.

4. Eotifera.1

5. AtinelidcL.

:1. Bnjozoa.

2. Bracliiopoda.

1. Lamellibranchiat'a.
I. Scaphopoda.

3. Amphineura.

4. Gastropoda.

. Cephalopoda.

1 . Crustacea.

r 1 . Myriopoda.

2. Arachnoid <.'.«.

3. Insect a.

1.

2.

3. Septilia.

4. J.WS.

5. Mammalia.

1 Unknown in the fossil state.

Sub-Kingdom I. PROTOZOA

PROTOZOA are unicellular organisms, with bodies consisting of sarcode (proto-
plasm), usually very minute, frequently microscopic in size, and without
differentiated tissues or organs. They are water-inhabitants, take in nourishing
matter either at any point on the periphery of the body whatsoever, or
through a so-called mouth (cytostome), and reject the undigested portions either
from any part of the body whatsoever, or from a definite point called the anal
aperture (cytopyge). The contractile sarcode almost invariably contains one or
more nuclei, and exhibits considerable diversity of structure and differentiation.
Locomotion is accomplished by means of vibratile cilia, flagella, pseudopodia,
or irregular processes of the periphery. Reproduction takes place by means of
budding or self-division, which latter process is often preceded by a temporary
coalescence (conjugation) of two individuals. Protozoa are divided into four
classes: Rhizopoda, Flagellata,- Infusoria, and Gregarina (Sporozoa), of which only
the first class is represented in the fossil state.

Class 1. RHIZOPODA.

Body-substance composed of richly granulated, jelly-like sarcode, which ttlfrni'ifi.'!/!
retracts, and again coalesces with irregular, finger-like, or thread-like
called pseudopodia.

Rhizopods have been so named on account of the property they possess of
protruding pseudopodia from the periphery of the body. Although serving as
a means of locomotion and for the taking up of nutritive matter, the pseudo-
podia represent no permanent organs, since they are protruded only for the
I IMS- ing occasion, and disappear again as they coalesce with the main body of
sarcode. The pseudopodia often exhibit protoplasmic streaming, and occa-
sionally interlace so as to form networks. Rhizopods usually secrete calcareous,
silicious, or chitinous tests, or build silicious skeletons of exceeding great
diversity of form. Enormous deposits are built up by their accumulation
on the sea-floor, and numerous strata of marine origin are largely composed
of their remains.

Four orders of Rhizopods are recognised: Forj^nifera, Ra^^ria, Amoebina?
and Heliozoa ; of these only the first two have parts capable of preservation.

1 Butschli, 0., Protozoen in Bronn's Classen und Ordnungen des Thierreichs, 1880-1889.

2 To the Amoebina, Huxley and Haeckel formerly assigned the so-called Bathybius, a reticu-
lated jelly-like substance composed of anastomosing strands, aiid occurring at great depths in the
Atlantic Ocean. Wyville Thomson and Moebius regarded it as a precipitate of calcium sulphate,

VOL. I C

18 PROTOZOA— RHIZOPODA CLASS i

Order 1. FORAMINIFERA. d'Orbigny.1
(Polythalainia, Breyn ; Thalamophora, Hertwig.)

Rhizopoda with slender, thread-like, or band-like, frequently anastomosing pscm/n-
podia, and usually with a calcareous, more rarely with an arenaceous or chitinous test.

The scarcely differentiated, richly granulated sarcode body of the
Foraminifera usually contains a contractile vacuole, and is enclosed by a shell
or test which is almost invariably calcareous in composition, although in some
cases it may be of a silicious or even chitinous nature, and which, as a rule, is
divided into chambers by interior partitions or septa. The sarcode com-
municates with the exterior either by means of a single large aperture (oral
or general aperture) situated at one extremity of the test, or by means of
innumerable fine pores (foramina) which perforate the shell. Through these
openings the sarcode emits usually long, filiform, net -like anastomosing
pseudopodia, in which often active granular currents are discernible.

Only a few forms secreting chitinous tests (Gromia) are fresh- water inhabit-
ants ; the rest are marine in habit. Foraminifera are usually so small in size
that, although perceptible to the naked eye, they can barely be discriminated
as separate individuals. Certain exceptionally large forms (Nummulites) attain
a diameter of four or five centimetres.

intermingled with decomposed organic matter. In deep-sea ooze, which consists chiefly of lime
carbonate, as well as in Bathybius, great quantities of minute calcareous bodies of various shapes
are found, such as also occur as an essential constituent of chalk, marls, and most marine lime-
stones belonging to older geological periods (cf. C. W. Giimbel, Neues Jahrbuch fiir Mineralogie,

1870, p. 753). Ehrenberg
termed these bodies morpho-

>»j^ ^ju ^ lites, and regarded them as

K/J PfiMiM$\ \ inorganic in nature. Huxley

(Journal Microscop. Science,

fcfclBl UN i *JS 1868, VIII. No. 6) and Haeckel

(Jenaische Zeitschrift, 1870,
V. 3, p. 18) regarded them at
first {

FIG. 1, c.—Coccoliths (Discoliths) from the Adriatic Sea ; upper side and (Fig. 1). The simple, disk-
in profile (after O. Schmidt). like varieties, convex on the

FIG. 2.— Coccospheres from the Atlantic Ocean (after Haeckel). iinnpr sulp iurl rnnpavp nn tin-

FIG. 3.-Rhabdoliths from the Adriatic Sea (after O. Schmidt). All "

figures magnified 700 diameters. lower, were termed discoliths

(Fig. 1, a, b) ; while those com-
posed of two closely applied disks of different sizes, resembling cuft'-buttons in profile, were referred
to as cyatlwliths (Fig. 1, c). Coccoliths are only visible under powers of 800 — 1000 diameters, and
exhibit, as a rule, a number of zones differing in their refractive indices, which are disposed about a
single, double, or star-shaped central granule. Frequently large numbers of coccoliths become
aggregated together in the form of freely suspended spherules or coccospheres (Fig. 2). Besides
coccoliths, other minute, rod-shaped, calcareous bodies are sometimes met with, which are charac-
terised by a discoidal or cruciform enlargement at one end. These are called rlitdxInUtli* (Fig. 3),
and their nodular aggregations rhabdospheres. Wyville Thomson, Carter, and Murray would
identify coccospheres as unicellular algae, or as sporangia of algae, while Haeckel creates for them
a special group, " Calcocytae," and assigns them provisionally to the Protophytes. According
to Harting, however, the action of ammonia generated by the decomposition of albuminous matter
held in solution in lime sulphate or lime chloride, causes the separation out of minute calcareous
disks which bear a striking resemblance to coccoliths. Hence it would appear that the formation
of excessively fine divided particles of lime in the sea should take place wherever there are decom-
posing albuminous, or nitrogenous substances present, and the calcium sulphate held in solution in
the water becomes precipitated as calcium carbonate.

1 Literature :
d'Orbigny, Atcide, Foramiuiferes fossiles du Bassiu tertiaire de Vienne, 1846.

,,KI,KK i » FOBAMINIPEBA 1!)

The test may be either unilocular, enclosing a single cavity (Monothalamia),
or it may be divided by septa into a greater or lesser number of chambers
(Poli/thalamia). Multilocular tests all grow from a single primordial chamber,
which is either spheroidal or elliptical in contour, and augment rapidly by
means of the successive apposition of new chambers, each a little larger than
the first, and each being applied in turn against the general pseudopodial
aperture of the preceding. All the chambers communicate with each other by
means of pores through which the sarcode is protruded. According as the
chambers are applied against one another in a linear series (Stichostega), in a
• spiral (Helicostega), in concentric rings (Cyclostega), in double or triple alterna-
tions of either straight (Enallostega) or spiral rows (Entomostega), or envelop
one another in irregular coils disposed in from two to five different planes
(Aguthistega), a great variety of forms may be produced. These differences
in external form, together with peculiarities in the mode of growth, were
employed by Alcide d'Orbigny as a basis for the first detailed system of
classification of the Foraminifera that has been devised. For specific diag-
noses, the relative size and shape of the shell, and varieties of ornamentation,
such as bands, lips, protuberances, points, spines, and the like, are of greatest
significance.

In certain Foraminifera which secrete calcareous shells (Nummulinidae,
Miliolidae, Lagenidae, Orbulina) a peculiar dimorphism has been observed, in that
while some individuals have an extremely
large primordial chamber (megasphere),
others, although differing in nowise in
external form and ornamentation, are
characterised by an extremely minute
1 n-imordiat chamber (microsphere, Fig. 4).
Those individuals which possess mega-
spheres are almost invariably much

inferior in size to those having micro- Fia 4.

spheres. De la Harpe refers this pheno- woeuMna /;/™/j/i, schiumb. Recent ; Bay of
menon to sexual differences; Munier-
Chalmas and Schlumberger claim, on
the other hand, that during the growth of those forms characterised by
microspheres, the megaspheres, which are in all cases originally present,
become absorbed and are replaced by an increased number of smaller
chambers. Van den Broeck argues against these hypotheses, and attempts
- to explain dimorphism as the result of different modes of reproduction (fission
and budding).

The finer structure of the shell or test, which has been thoroughly
investigated by Carpenter and Williamson, is of great importance in the
classification of the Foraminifera.

Chitinow tests are as a rule single -chambered (monothalamous), imper-
forate, and are provided with a single large-sized oral aperture. Silicious

I'.ln-.-tiberg, C. Gf., Mikrogeologie, 1854, and Abhandlungeu der Berliner Akademie, 1839.

X-lni/tze, Max, Ueber den Organismus der Polythalamien, Leipzic, 1854.

Carpenter, W. B., Introduction to the Study of the Foraminifera, Ray Society, 1862.

Reuss, E. A., Numerous Reports in Sitzuugsberichte der Wiener Akademie, from 1860 onwards.

,NV// t'-ni/,',; (',>,i rtid, Saggio di una Classificazione dei Foraminiferi, Bollet. Comitato Geol., 1876.

Jinx///, II'. /;., Monograph of Carboniferous and Permian Foraminil'era, Palaeontograph. Soc., 1876.

Brady, Jr. B., Report on the Foraminifera, Scientific Results Challenger Exped., Zoology, XL, 1884.

•20

CLASS I

PROTOZOA— RH I ZO L'GIM

tests consist of minute grains of sand, often intermingled with particles of
lime and other foreign matter, the particles being held together by a silicious
or argillaceous cement. The tests are unilocular or multil octilar, occasionally
attain considerable size, and are either imperf orate (Fig. 5, A), or, in addition
to the either simple or sieve-like principal apertures, are punctured by

FIG. 5.
A, Section through an iniperforate arenaceous

Roeni.) 13, Section through a perforate arenaceous
test showing coarse tubuli, highly magnified (Ple-
i 'jibbosum, d'Orb.)

FIG.

•tion of vitreous perforate test with fine
tubuli (Nodosaria rapa, d'Orb.) B, Portion of
periphery, and section of a vitreous perforate test
with coarse tubules less closely set together
(Globigerina conglomerates, Sch wager).

tubules, through which the pseudopodia are emitted (Fig. 5, B). Calcareous
tests are also sometimes (Miliolidae, Textularidae) encrusted with agglutinated,
compactly cemented sandy particles, and hence consist of an interior calcare-
ous, and an exterior sandy-silicious layer (Fig. 6). The greater number of

FIG.

Clii,i.'ii-nmmina textulariformis,
Holier, sp. Perforate calcareous
test invested with arenaceous
envelope. ••% (after Moller).

FIG. S.

OpercuKna complanata, Bast. Miocene ; Bor-
deaux, a, natural size ; b, median longitudinal
section ; c, transverse section, greatly enlarged.

Lam. Vitreous perforate
test with spur-like sup-
plemental skeleton tra-
versed by canals.

Foraminifera, however, secrete tests composed of carbonate of lime, which
may be either porcellaneous and iniperforate, or vitreous and perforate in
structure. In the first class (Imperforata) the shell is homogeneous, and
appears in reflected Kght as an- opaque mass (Fig. 4) ; in the second (Perforata)
it is lustrous, transparent, and perforated by numerous fine tubules which
pass through the walls radially. These tubules, which are visible on the peri-

FOIIA.MIXIFERA

21

as tine pores (foramina), are either all equal in diameter, being extremely
HUM 11 and closely set together (Fig. 7, A), or an; larger in calibre and more
widely separated from one another (Fig. 7, B}. Certain vitreous, perforate
1'oiaminifera are still further provided with coarser, anastomosing canals,
which are restricted to definite parts of the shell, such as the septa, or the.
median plane of the
spiral, in forms which
are symmetrically con-
voluted. In the livin-
state, these larger canals
are occupied by bands or
stolons of sarcode, but
there is no connection
1 >et ween them and the
other foramina or radial
tubules. In many forms
exhibiting more com-
plicated structure, cal-
careous deposits are ob-
served, which are dis-
tributed partly over the
periphery, and partly in
cavities and depressions
within the shell itself.
This is the so-called in-
termediate or supplemental
skeleton, which often
gives rise to peculiar
excrescences on the peri-
phery (Fig. 9), and in
some cases is also pierced
by tubules.

Reproduction in the
Foraminifera takes place
either by means of fission,
or by means of small
nuclei which originate i,,.,.,,.,

within thp rarfnt inrli &> Individual Discoliths and Cyatholiths ; c, Coccospheres ; d, Globigerina;
[~ e, Globi,,,;-;,;, with bnrsted test; /, Textitlaria; g, g', Radlolaria; h, i,
Victual, invest themselves Diatoms ; k, I, Sponge spicules ; m, Mineral fragment.

with unilocular or multi-

locular tests, and forthwith abandon the parent shell, whereupon the latter

falls to pieces.

The vast majority of Foraminifera are marine in habit. They occur in
shallow water bordering the coasts, sometimes attached to algae, sometimes
creeping on the bottom. A few genera are extraordinarily abundant in the
open sea, occurring at different depths as free-swimming forms, and also on the
floor of the ocean. Enormous quantities of their remains are spread over large
tracts of the sea-bottom, and down to a depth of 2300 fathoms they remain an
essential constituent of the chalk-like deep-sea ooze. This is a finely divided
agglomeration of decomposed calcareous substances, such as the shells of

FIG. 10.
ooze magnified 700 diameters.

with Coccoliths ;

22

PROTOZOA— RHIZOPODA

CLASS I

mollusks, corals, bryozoans, coccoliths, radiolarians, diatoms, sponges, and
Foraminifera. Of the latter, certain genera are remarkable for their extra-
ordinary abundance (Globigerina, Orbulina, Pulvinulina, Biloculina), (Fig. 10).

In the Atlantic and Pacific Oceans Gloligerina ooze is the prevailing deep-
sea deposit ; in the North Sea, along the coast of Norway, Bilociilina ooze.
Numerous limestones and marls of older geological periods exhibit great
similarity in structure and chemical composition to the now forming deep-sea
oozes. White chalk (Fig. 11) is clearly a variety of abyssmal ooze, from which
silicious constituents have become segregated out, and in which Textularia
predominate instead of Globigerina. Certain of the Eocene limestones of the

Specimen of prepared white chalk from Meudon, as seen in
transmitted light under power of 300 diameters, showing Textularia,
Globiyerina, and Rotalia.

FIG. 12

Thin slice of Pliinerkalk from Bohemia
viewed in transmitted light under power
of 50 diameters, showing sections of
Nodosaria, Rotalia, Frondiculcrin. and
numerous isolated Globigerina chambers.

Paris basin are composed almost exclusively of the tests of Miliolidae, while
others are made up of Alveolinae, and Nummulites. During the Carboniferous
period the chief rdle as rock -building organisms was played by Fusilina.
Many dense, apparently homogeneous, or even semi-crystalline limestones of
various ages, when examined microscopically in thin sections, are seen to be
composed in large part of Foraminifera and other organic bodies (Fig. 12).

Fossil Foraminifera are best preserved, being usually detachable from the
matrix, and at the same time occur most abundantly, in unconsolidated marls and
clays which are interbedded with calcareous strata, or in limestones of a chalky
or earthy character.

The tests of Foraminifera were first discovered by Janus Plancus, in 1730,
on the beach of Rimini, and in the following year they were found by Beccari
in the Pliocene of Bologna. They were long considered to be shells of
mollusks, and were described by Breyn, Soldani, Fichtel, d'Orbigny, and
others as Cephalopoda foraminifera, in distinction from Cephalopoda siphonifera.
Dujardin, in 1835, was the first to recognise their true character as belonging
to the Rhizopoda,

ORDER i FORAMINIFERA 23

Foniminifera are divided into the four following sub -orders: — Chitinosa,
. Ifft/lntiiiantia, Porcellanea, and Vitro-Cakarea.

Sub-order A. CHITINOSA.^ Schwager.

Test chitinous, imperforate, sometimes encrusted with agglutinated particles, and
with pseudopodial aperture at one or at both extremities.

This group comprises the single family Gromidae, which is made up chiefly
of fresh-water forms, and whose occurrence in a fossil state is unknown. £ p.Q

.

Sub-order B. AGGLUTINANTIA. Schwager.

Test composed of agglutinated sandy particles or other silicious foreign bodies, which
are held together by a compact, silicious, or argillaceous cement.

Family 1. Astrorhizidae. Brady.

Test arenaceous, with rough exterior, usually unsymmetrical, often attaining con-
siderable size; the sandy particles are sometimes only loosely cemented together;
occasionally branching or developing radial prolongations ; septa wanting.

Recent, and very abundant at great depths. Fossil in Palaeozoic and
Jurassic formations.

Saccammina, Sars. (Fig. 13). Shell thick, with labyrinthiform interior;
spherical, pear-shaped, or fusiform, with tubular prolongations at one or both
ends ; sometimes united together in chains. Ordovician (Ayrshire), Devonian
(Canada), Carboniferous, and Recent. Entire strata of Carboniferous rock
near Elf hills, Northumberland, are built up by S. Carteri, Brady.

Large-sized species of Astrorhiza, Psammosphaera, Saccammina, Hyperammina,
and Rhabdammina are described by Hausler from the Upper Jurassic (Trans-
versarius beds) of Switzerland.

Family 2. Lituolidae. Brady.

Test arenaceous or composed of agglutinated particles of various kinds ; more or less
regular in contour; divided by septa into a number of chambers, or more rarely single-
chambered; free-swimming or attached; septal planes irregular, sometimes labyrinthic.

Recent species occur mostly at considerable depths.

Thurammina, Brady. Test free, monothalamous, irregularly spheroidal,
usually with excrescences or spiny processes. Upper Jurassic and Recent.

Ammodiscus, Reuss. Test free, monothalamous, depressed, spirally coiled in
a single plane, with terminal pseudopodial aperture. In all formations from
Carboniferous to Recent.

Trochammina, Park. Jones (Fig. 16). Test thin, smooth, consisting of com-
pact, ochre-like cement with embedded sandy particles ; turbinate, or spirally
wound like a snail-shell (trochoid) ; imperfectly chambered. Lias to Recent.

Placopsilina, d'Orb. (Fig. 15). Test rough, arenaceous, attached, and
divided into pyriform or spherical chambers, which are joined in chains or are
irregularly attached together. Lias to Recent.

24

PROTOZOA— RHIZOPODA

CLASS I

PJieophax, Montf. (HaphsticJie, Reuss), (Fig. 14). Test free, rod-shaped or
slightly bent; septa simple (Itheophax) or labyrinthic (Haplostiche) ; pseudo-
podial aperture at extremity. Carboniferous to Recent.

/Lihiola, Lam. (Haplophragmvm, Reuss), (Fig. 17). Test free, crosier-shaped

FIG. 13.

FIG. 14.

Jlo.plostiche
horrida, Schwa -
ger. Upper
J urassic

A, Saccammimt, Carteri,
Brady. Carboniferous Lime-
stone; Elfhills, Northum-
berland. 1/1- B, Fractured pressa
test, filled . with interior Gruibingen,
calcite. io/j (after Brady). Wiirttemberg.

pper
(Im-

Placopsiliua
rostrata, Quenst.
sp. Upper Jur-

Trochammina

assic (Impressa tens, Karrer. Vienna

clay) ; clay) ; Reichen-
bach, Win-Item
berg.

sandstone (Senonian) ;
Hutteldorf, near
Vienna.

(Haplo-'
phragminm) irregu-
lare, Roemer. Sca-
phiten - Planer ;
Krb'ndorf, Bohemia.

or spirally wound. General aperture simple or sieve-like ; septa simple (Haplo-
phragmium) or labyrinthic (Lituola). Carboniferous to Recent; particularly
abundant in Jurassic and Cretaceous.

Family 3. Orbitolinidae. Zittel.

Test silicious, imperforate, bowl-shaped, and composed of concentric rings which
are partitioned off into numerous chambers.

Orbitolina, Lam. (Fig 18). Test silicious, with
agglutinated sandy particles ; bowl-shaped to depressed
conical ; upper side convex, lower side slightly hollow.
Periphery smooth, or with concentric bands, imperforate.
Test composed of multilocular rings, the chambers
communicating with one another on all sides by means
of pores. The peripheral portion of each chamber is
divided up into smaller compartments by two secondary
septa disposed at right angles to each other. Very
abundant in the Lower (0. lenticularis, Lam.) and Upper
Cretaceous (0. concava, Lam.)

FIG. IS.

c, Transverse section
larged). .

(en-

Sub-order C. PORCELLANEA. Schwager.

Test calcareous, porcellaneous, imperforate.

Under starved conditions (e.g. in brackish water) the test may assume a
chitinous or arenaceous character, or may become encrusted with a thin, homo-
geneous, silicious envelope. The majority of recent forms inhabit shallow water ;
only a few occur at abyssmal depths.

OKI'KK I

FORAMIXIKKK'A

Nubecularidae. Bnuly.

attached, extreme!// //•/>'>////"/• in rnnti,n,\
Triassic to Recent.

Kaniily 1.

Test comparatively A//v//--.s-/':r»/,
with one or with several general apertures.

The recent genus Nubecnlaria, Dfr., belonging to this family occurs fossil'
in ;ill formations from the Triassic onward, and is particularly abundant in
the Miocene (S;irm;iti;ui stage) of Bessarabia, Russia.

Family 2. Peneroplidae. Schwager.

Test piano-spiral or cyclical, bilateral!// x//n/ metrical, usually polythalamous, more
rarely monothalamous. Triassic to Recent.

Cornuspira, Schultze (Fig. 19). Test composed of numerous piano-spiral
convolutions ; oral aperture simple, terminal ; monothalamous. Lias to
Recent.

Peneroplis, Montf. (Fig. 20). Test discoidal, complanate, polythalamous ;
direction of growth primarily spiral, gradually becoming rectilinear, while

FIG. ly

FIG. 22.

Cornuspira pol //•

&yra, Reuss. Peneroplis planatus, " Orliodt na luimmis A, Orbitolites compl<m<tt", Lam. Eocene

ligocene : Hun- Montfort. Recent; malls, d'Orb. Plio- (Calcaire Grossier): Paris. B, Portion of

gary. Mediterranean. cene ; Sienna, Italy. same enlarged.

rapidly increasing in breadth. Septa perforated by numerous foramina.
Tertiary to Recent.

Orbiculina, Lam. (Fig. 21). Test discoidal; segments spiral at commence-
ment, later becoming annular ; polythalamous, septation regular, chambers
subdivided ; septa and walls of segments perforate. Tertiary to Recent.

Orbitolites, Lam. (Fig. 22). Test discoidal, circular in contour, both sides
slightly concave in the centre, of comparatively large dimensions, and com-
posed of segments which
are disposed concentrically
about a few spirally wound
primordial chambers.
Polythalamous; septa
radially disposed, and per-
forated by symmetrically

v , -i , j f . T17 ' Alveoli na Bosci, d'Orb. Eocene (Calcaire Grossier) ; Paris. .4, Frontal

distributed lOramma. In aspect. B, Test laid open so as to show conformation of interior;

the more complicated c

forms the principal segments are covered over on both sides by a thin, super-
ficial, multilocular layer, the chambers of which are likewise arranged in con-
centric rings, and communicate with the principal chambers by means of pores.
Lias (0. praecursor and 0. circumvulva, Giimb.), Cretaceous (0. maci'»j»n-<i,

FIG. 23.

PROTOZOA— RHIZOPODA

CLASS I

d'Orb.), Tertiary (0. complanata, Lam.), and Recent. An important rock-
building genus.

Alveolina, Bosc. (Borelis, Montf.), (Fig. 23). Test fusiform, elliptical, or
spherical, usually elongated in the axis of convolution, and composed of
spirally wound segments which completely envelop one another. Each seg-
ment is partitioned off into long, narrow chambers by septa arranged at right
angles to the axis, and these are subdivided into chamberlets by a second set
of septa running transversely to the first set. Each of the secondary
chamberlets communicates with the adjacent primary chamber by means of a
single round aperture. In certain recent species the secondary chamberlets
are also subdivided. The genus begins in the Cenomanian, continues in
extraordinary profusion, and becomes a most important rock-builder in the
Eocene (Calcaire Grossier of the Paris basin, Alveolina limestone of Istria,
Dalmatia, Greece, and the Libyan Desert).

Family 3. Miliolidae. Carpenter.

Test either entirely composed of coil-like segments, or convoluted only at commence-
ment. Primordial chamber dimorphous. Triassic to Recent.

Miliola, Lam. (Figs. 24, 25). Segments disposed in ' coil- shaped loops
about a few spirally wound primordial chambers. Each loop is constricted at

FIG. 24.

A, Biloculina inornata, d'Orb. From the Miocene Tegel ; Baden, near Vienna. />', TrilocuUna gibba, d'Orb.
Oligocene sand from Astrupp. C, Spiroloculina Badensii, d'Orb. Miocene Tegel ; Baden, near Vienna. D, Quin-
queloculina saxorum, d'Orb. Eocene (Calcaire Grossier) ; Grignon, near Paris.

the extremities so as to form a septum of its own walls. Terminal pseudo-
podial aperture either curving in the form of a crescent about a tooth-like pro-

jection, or branching
dendritically (Lacazina).
Forms having all the seg-
ments disposed in a single
plane, and all externally
visible, are grouped to-
gether in the sub -genus
Spiroloculina, d'Orb. ; with
all the segments completely

A, Longitudinal section of
Biloculina inornata, d'Orb.
(enlarged). B, Transverse
section of Quinqucloculina
saxornm, d'Orb. (enlarged).

FIG. 26.

FIG. 27.

I''<ilniJuria dis-
colithes, Defr.
Eocene (Calcaire
Grossier); Paris.

enveloping

cronata,
Recent ;
terranean

one another,

,,Q ^ -tvwi/i/u/t/frfiw/, VA Orb.j segments
M«-<ii- disposed in three or in five
different planes, TrilocuUna
and Quinqueloculina, d'Orb. The great variety and extraordinary profusion of
this genus combine to make it one of the most important of the rock-building
Foraminifera. Massive beds of Eocene limestone (Paris basin, Pyrenees) are

ORDKH

FORAMINIFERA

made up of Miliola remains ; at the present day calcareous deposits are being
formed by Biloculina in the North Sea west of the coast of Norway. Miliohi
begins in the Triassic, and attains its maximum development in the Tertiary
and Recent periods.

fubtdaria, Defr. (Fig. 26). Like Biloculina, but relatively larger. Oral
aperture sieve-like ; chambers not hollow, but filled with porcellaneous cal-
careous matter, and perforated by numerous anastomosing canals which run
parallel with the axis of convolution. Abundant in Eocene of the Paris
l.asin.

Vertebralina, d'Orb. (Fig. 27). Test consisting of coil-shaped loops at
commencement, afterwards becoming rectilinear. Tertiary and Recent.

Sub Order D. VITRO-CALCAREA. Schwager.

Test calcareous, vitreous, perforate ; more rarely silicious, or silicious with vitro-
perf orate substratum ; punctured by numerous fine tubules for the emission of pseudo-
podia. Silurian to Recent.

Family 1. Lagenidae. Carpenter.

Test perforated only by very fine and closely-set tubules, without supplemental
skeleton or canal system.

Lagena, Walker (Fig. 28, A). Test single-chambered, spherical, ovate,
or flask-shaped, with terminal oral aperture. Silurian to Recent.

Nodosaria, Lam. (Fig. 28, B). Test rod-shaped ; chambers arranged in a

FIG. -2S.

.1, I.iii,,<ii,i semtitriata, Williamson. Antwerp Crag (Pliocene); Antwerp. B, Nodosaria spinieosta, cl'Orb.
'IViM (Miocene) ; Baden, near Vienna. C, Dentalina eleyans, d'Orb. Same locality. D, Cristrllarin r«t idnta, Lam.
Srapliiti'n-Hiincr (Turonian) ; Bohemia. E, Vagimdina recta, Reuss. Neocomian ; Salzgitter, Hanover. F,
J.liiiiiiliiin 1-1,,-ifntn, d'Orb. Tegel (Miocene) ; Baden, near Vienna.

straight line and set off from one another by constrictions ; oral aperture
round, terminal. Widely diffused from Silurian to Recent.

Dentalina, d'Orb. (Fig. 28, (7). Like the preceding, but slightly bent.
Carboniferous to Recent.

Vaginulina, d'Orb. (Fig. 28, E). Test straight, laterally compressed;
segments flattened, with obliquely directed septa. Triassic to Recent.

Marginulina, d'Orb. Early segments curved or helicoid, later ones rec-
tilinear. Oral aperture slit-like. Triassic to Recent.

Oristellaria, Lam. (Fig. 28, D). Test regularly piano-spiral, with convolu-
tions completely enveloping one another. Oral aperture round. Triassic to
Recent.

28

PROTOZOA— RHIZOPODA

CLASS I

A, Glandulina inflata, Borneui.
Polymorphina injkita, Williamson.

FIG. 29.

Septarienthon (Oligocene) ; Herinsdorf. Ji,
Recent; German Ocean. C, Dimoi-phina sp.

LinguUna, d'Orb. (Fig. 28, F). Test straight, compressed ; segments
attached in rectilinear series. .General aperture terminal, slit-like. Triassic
to Recent.

Glanduliha, d'Orb. (Fig. 29, A). Test short, ovate; segments united in
rectilinear series, half-embracing one another. General aperture round, ter-
minal, usually tubu-
lated. Triassic to
Recent.

FT ondicu laria,
Defr. (Fig. 29, D).
Test straight, ex-
tremely compressed,
and foliately ex-
panded. Chambers
greatly reflexed,
laterally embracing-
one another. General
aperture round, ter-

Pliocene ; Sienna, Italy. D, Frondicularia Goldfussi, Reuss. Scaphiten- Planer ; rm'rml Triaeeip tn

Diilmen, Westphalia. E, Ucigerina pygmaea, d'Orb. Tegel (Miocene) ; Baden, mi

near Vienna. Recent.

P o I y m o rp h in a,

d'Orb. (Fig. 29, B). Segments irregularly helicoid, or arranged in double
series more or less enveloping each other and varying in shape. General
aperture round, terminal. Triassic to Recent.

Dimorphina, d'Orb. (Fig. 29, C). Early chambers irregularly or triserially
disposed, later ones following in a straight line. Cretaceous to Recent.

Uvigerina, d'Orb. (Fig. 29, E). Segments dissimilar, disposed in triple
series, and spirally wound like a snail-shell. Eocene to Recent.

Family 2. Textularidae. Schultze.

Test in larger forms arenaceous, with calcareous basis perforated by coarse tubules ;
in smaller forms vitreous, perforate ; segments regularly or only in part arranged in
two (rarely more than two) alternating series.

Textularia, Defr. (Fig. 30, A). Test usually elongated, straight, tapering,
or turbinated. Chambers biserial, alternating, and communicating with each
other by means of slit-like apertures. Carboniferous to Recent. Extremely
abundant in the White Chalk.

The genera Textularia, s. str., Grammostomum (Fig. 30, D), and Bolivina (Fig.
30, B) of the calcareous forms ; and Plecanium (Fig. 30, (7), Eigenerina,
Gaudryina (Fig. 30, E), Clavulina (Fig. 30, F), and Verneuilina are founded upon
various minor modifications.

Bulimina, d'Orb. (Fig. 31, A, B). Test calcareous, the alternating
chambers arranged in an elongated spire. Triassic to Recent.

F'alvulina, d'Orb. (Fig. 31, E). Test arenaceous with calcareous basis.
Chambers in triple series arranged in screw-like spiral. Carboniferous to
Recent.

Climacammina, Brady (Cribrostomum, Moller), (Fig. 31, B, C). Test
arenaceous with calcareous basis. Chambers biserial, rectilinear. Oral aper-
ture porous- Abundant in Carboniferous Limestone (cf. Bigenerina, d'Orb.)

OR|>KK I

FORAMINIFEBA

Tetrctfaxis, Khrl»<;-. (Fig. 31, F}. Test calcareous, conical. Alternating
chambers arranged in a turbinate spire. Carboniferous Limestone.

FIG 30.

. I . Ttxtularia ijlnlilfi: m , llm

'Jpper Cretaceous (Seuonian) ; Pattenauer Stollen, near Traunstein, Bavaria.

/;, Bolivina incrcusatd, Reuss. Upper Cretaceous ; Gotzreuther Graben, near Siegsdorf, Bavaria. 6', Plecanium
(/ibbosum, d'Orb. Pliocene ; Sienna, Italy. D, Gmmmostomum (Vulvulina) gramen, d'Orb. Recent ; Cuba. E,
iTattdryina rugosa, d'Orb. Upper Cretaceous, Gotzreuther Graben, near Siegsdorf. F, Clavulina cvmmunis,
d'Orb. Miocene ; Baden, near Vienna.

Cassidulina, d'Orb. (Ehrenbergina, Eeuss) (Fig. 31, G). Test calcareous, the

FIG. 31.

.!. HiiUmina BucJiiana, d'Orb. Miocene (Leithakalk) ; Nussdorf, near Vienna. B, Bulimina pupoidcs, <1 Orb.
Same locality. C, Climacammina textulariformis, Moller. Carboniferous Limestone; ])ugno, Russia, Longi-
tudinal section. -°/i (after Moller). D, Climacammina pyriforme, Moller, sp. Carboniferous Limestone ; Sloboda,
Russia. 20/j (after Moller). E, Valvulina sp. Eocene (Caleaire Grossier) ; Grignon, near Paris. F, Tetrataxis
ronica, Ehrbg. Carboniferous Limestone ; Bachtin, Russia. s°/i (after Moller). (;, Ehmibergina serrata,
Reuss. Miocene ; Baden, near Vienna.

alternating biserial segments either completely or only partially coiled.
Tertiary and Recent.

30

PROTOZOA— RHIZOPODA

CLASS I

Family 3. G-lobigerinidae. Carpenter.

Test free, calcareous, perforated by coarse tubules; monothalamous or poly-
thalamous ; chambers globular, either irregularly disposed or imperfectly spiral.

Of the two most important genera belonging to this family, Orbulina, d'Orb.
(Fig. 32, A}, is unilocular, and GloUgerina, d'Orb. (Fig. 32, C], multilocular. The

individual chambers
usually conduct into a
common central'canal.
In both genera the test
is often covered with
extremely delicate
calcareous spines,
which, however, are
very easily broken
off, and are never
preserved in the fossil

Austriaca, d'Orb. Miocene Tegel ; Baden, near Vienna. ' C, GloUgerina con- State. These genera
fjlomerata, Schwager. Pliocene; Kar Nikobar Island, a, Inferior surface; QT,A AYPA«civpli7 rliflfncp
b, Superior surface ; c, Portion of periphery ; d, Transverse section enlarged. ' ev L

in modern deep-sea

deposits (Globigerina ooze) ; they occur sparingly in Mesozoic formations,
beginning with the Triassic, and first rise to importance during the late
Tertiary period.

Sphaeroidina, d'Orb. (Fig. 32, B}. Cretaceous to Recent.

FIG. 32.

Family 4. Botalidae. Carpenter.

Test calcareous, rarely arenaceous or silicious, finely or coarsely perforated, fre-
quently with intermediate skeleton, free or attached, turbinate or discoidal in contour.
Segments usually arranged in an elongated spire, although in some forms

Discorbina, Park. Jones (Fig. 33, A, B). Test coarsely perforated, tur-
binoid. Inferior surface broad and flat ; umbilicus often filled with deposit
of intermediate skeleton. Cretaceous to Recent.

Planorbulina, Park. Jones (Fig. 33, C). Test coarsely perforated, com-
planate, usually attached, superior and inferior, surfaces dissimilar ; early seg-
ments arranged in depressed spire, subsequently becoming cyclical. Lias to
Recent. The d'Orbignyan sub-genera Truncatulina, Anomalina, Planulina,
etc., are based upon different modifications in form.

jRotalia, Lam. (Fig. 34, A). Test finely perforated, with segments in
turbinoid spire. Septa composed of two slightly separated lamellae, .with
anastomosing canals occupying the intermediate space. Basis often
thickened by supplemental skeleton. (?) Silurian. Upper Jurassic to
Recent.

Pulvinulina, Park. Jones (Fig. 34, B}. Rotaliform, but septa single and
without interseptal canal-system. Lower Lias to Recent.

Endothyra, Phill. (Fig. 34, • C). Test calcareous ; composed of an exterior
coarsely perforated, and an interior compact layer consisting of minute grains
of limey matter ; polythalamous ; irregularly spiral. General aperture

MKDKK I

FORAMINIFERA

porous. Abundant in Carboniferous Limestone, and according to Brady, also
recent.

Cakarina, d'Orb. (Fig. 35). Test discoidal, with dissimilar upp.-r ;iiid

FIG. 33.

.1, l>ixr.,rl>in<i (Axti •i-ii/i'i-iiKi.) pianos-is, d'Orb. Miocene (Leithakalk) ; Nussdorf, near Vienna. 11, I>ix
up. Recent, a, Under side; 1>, Upper side; c, Lateral view; d, Median section. C, Planorbulinu, Mediter-
.-, d'Orb. Recent ; Mediterranean, a, Inferior surface ; I, Superior surface ; c, Transverse section.

lower surfaces, chambers spirally wound. Exterior encrusted with supple-
mental skeleton, which fills up all depressions, and builds spiny or spur-like

FIG. 84.

A, Rotalia Beccari, Lin. Pliocene ; Sienna, Italy. K, Pulvinulina Partschi, d'Orb. Miocene (Tegel) ; Baden,
near Vienna. C, Endothyra Panderi. Mdller. Carboniferous Limestone ; Russia. 2o/j. D, Endothyra parva.
Moller. Carboniferous Limestone ; Russia. Longitudinal section, loo/j.

appendages traversed by coarse canals.
Particularly abundant in Maastricht Chalk.

TinoporuSy Montf. Patdlina, Williamson.

The recent genera Carpentaria, Gray, Poly-
trema, Gray, Rwpertia, Jones, etc., are distin-
guished by their extremely irregular, usually
attached, coarsely perforated tests, which occa-
sionally attain considerable size, and often
contain agglutinated, sandy, or other foreign
particles. Thalamopora, Roem., occurring in
the Cretaceous, probably also belongs to this
family. ,

Upper Cretaceous to

Holland.

Family 5. Fusulinidae. Moller.

Test calcareous, perforate, polythalamous, fusiform or spherical, composed of
numerous spirally inrolled whorls (symmetrically involute]. The whorls are divided

32 PROTOZOA— RHIZOPODA CLASS i

into principal chambers by />/•//><///// i/lm-tn/ *c/ifu, and these are further broken,
into second arii diamlx-iictx /<// trti.Htrrw partitions. Septa single or more
double.

Schica ;/<•/•/ na, Moll. Test spherical, finely perforated. Primary and
secondary septa simple, thin, straight ; secondary chainberlets communicating
with the next following principal chamber by means of a basal aperture.

A, Fiuulinactflndriea, Kisoh. Carboniferous Limestone ; Sarauisk, Russia. Natural size. A C, Same species
showing various cross-sections enlarged. D, Enlarged srrtinn showing chambers communicating by means of
foramina, (a, 6).

Abundant in Carboniferous Limestone of Japan, China, Sumatra, North
America, and Russia.

^i/F-usulin-a, Fischer (Fig. 36). Test fusiform, laterally elongated like
Alveolina, coarsely perforated. Septa of principal chambers undulating, and
united so as to form secondary chamberlets. Excessively abundant in
Carboniferous Limestone of Europe (Russia), Asia, and North America.

Family 6. Nummulinidae. Carpenter.

Test calcareous, finely perforated, lenticular or discoidal, often attaining consider-
able dimensions ; polythalamous, and composed either of discoidal spiral whorls or of
cycloidal rings. Pillars of compact intermediate skeleton present, and in most f units
also an anastomosing canal-system occupying inter septal spaces and certain other
portions of the shell.

Archaediscus, Brady. Test lenticular, unsymmetrical, spirally coiled. The
segments irregularly constricted and expanded so as to form chambers. Septa
and canal-system wanting. Carboniferous Limestone.

Amphistegina, d'Orb. (Fig. 37). Test lenticular, slightly inequilateral,
spirally rolled. Whorls divided into chambers by numerous single septa in
which canals are not present ; solid wedge-shaped deposit of intermediate
skeleton near the umbilicus. On one side the volutions completely enclose
one another as far as the centre, on the other they overlap only partially by
means of alar prolongations extending inwards. Chambers communicate with
each other by means of a slit along the basis. Miocene to Recent. Par-
ticularly abundant in Miocene.

Operculina, d'Orb. (Fig. 38). Test discoidal, complanate, composed of three
to six rapidly expanding spiral whorls, which are polythalamous and non-
involute. Septa and marginal cord traversed by a direct canal -system,
which gives off numerous branches. Cretaceous to Recent. Particularly
abundant in Eocene.

Heterostegina, d'Orb. (Fig. 39). Like Operculina, but with chambers sub-
divided by secondary septa into chamberlets. Tertiary and Recent.

, d'Orb. (Phacites, Gesner ; Leuticulites, Lam.), (Figs. 40-42). Test

ORDER I

FORAMIXIFERA

33

symmetrically lenticular or discoidal, composed of numerous spindly arranged
polythalamous volutions, and usually with columnar intermediate skeleton,
which forms small excrescences on the periphery. The septa and marginal

FIG. 37.

.1 mpli istfjina Haueri, d'Orb.
Miocene (Leithakalk) ; Nuss-
dorf, near Vienna. ", Exterior
views, enlarged ; b, Natural
si/i1 ; c, Median section,
greatly enlarged ; d, Trans-
action, greatly en-
larged.

0-perculina complanata, Bast., sp. Miocene ;
Bordeaux, a, Natural size ; 6, c, Median and
longitudinal sections, greatly enlarged.

Heterostegina costata, d'Orb.
Miocene (Leithakalk) ; Nuss-
dorf, near Vienna.

cord contain a coarse, anastomosing canal-system, as in Opercnlina. Primordial
chamber spherical, sometimes large, sometimes exceedingly minute in size.
The whorls either merely embrace one another (Assilina) (Fig. 41), or they
completely envelop one another by means of alar prolongations reaching

FIG. 40.

cfr. Lucasanus, Dfr. Eocene; Kressenberg, Upper Bavaria. Several times enlarged.
a, Marginal cord with canal-system ; i>, Septal plane with interseptal canal-system; c, Interior of chamber;
•/. 1'im-ly perforate periphery ; e, Small pillars of intermediate skeleton.

in \vards to the centre (Nummuhna). The septa are pierced in the median,
plane by an oblique slit-like aperture, and also extend into the saddle-shaped
•ilar prolongations of the chambers. They are directed in the groups Jfnifiafat
and tftriatae in straight or slightly curved lines (Figs. 40 and 42, C) • in the
tfhniiifae they follow meandering courses (Fig. 42, A}-, and in the Itrfii-Hlnfn,-
(Fig. 42, B) they form an interlacing network by means of connecting pro-
VOL. I D

34

PROTOZOA— RHIZOPODA

CLASS I

cesses. The ramifications of these lateral processes (Filet cloisonnaire) may be
readily seen on fracturing a portion of the test, and are a
valuable aid in the determination of species. The oldest
Nummulites (N. pristinus, Brady) occur very sparsely in the
Carboniferous Limestone and Upper Jurassic, but are dis-
tinguished from the typical later forms by the absence of
an interior canal-system in the marginal cord. The typical
Nummulites which are so characteristic of the Eocene (Num-
mulitic limestone) in Europe, North Africa, Asia, and Central
America, often build up massive formations. The largest

Eocene?pyrenees?w' species (N. Giztliensis, Ehrbg., N. orbiculatus, Schafh.) attain
a diameter of 60 mm. ; the smallest species does not exceed

2 mm. ; recent representatives comparatively scarce.

Polystomella, d'Orb. (Fig. 44) ; Nonionina, d'Orb. ; Cydodypeus, Carp.

Tertiary and Recent.

FIG. 41.
Nummulites (Assi-

£12

FIG. 42.

A, Nummulites Gizehensis, Ehrbg. Eocene ; Libyan Desert. Natural size. A 3, Specimen with eroded peri-
pheral portion, showing arrangement of septa. B*2, Nummulites laevigatus, Lam. Caleaire Grossier ; Paris.
Natural size. B*, Portion of same enlarged. G'12, Nummulites Ramondi, Defr. Eocene (Nummulitic lime-
stone); Pyrenees. Natural size. C$, Enlarged section.

\/ Orbitoides, d'Orb. (Hymenocydus, Bronn ; Lycophrys, Montf.), (Fig. 45). Test
discoidal, with circular or stellate contour, of ten. bent, exterior smooth or. with

FIG. 43.

A, Nummulitic limestone with horizontal sections of
N. distans, Pusch. Peyrehorade, in the Pyrenees. £,
Nummulitic limestone showing sections of N.
Defr. Zakophane in the Carpathians.

N. Lucasanus,

FIG. 44.

f Polystomella crispa, Lam.
Pliocene ; Sienna, Italy.
(Highly magnified.)

radial striae, and composed of numerous concentric annuli disposed about a

ORDER I

FORAMINIFERA

35

primordial spiral of three to five whorls. The rings are divided by transverse
partitions into small rectangular chambers, and the septa and marginal cord are
traversed by canals. Superimposed over the median series of prinripal
chambers on both sides are several layers of flattened secondary chamberlets,

FIG. 45.

A, Orbitoides papyracea, Boubee. Eocene (Ferruginous sandstone) ; Kressenberg, Upper Bavaria. (Greatly
enlarged). 1 Median chambers ; a Lateral chambers ; » Compact pillars of intermediate skeleton. B, Portion of
miMlian transverse section, highly magnified; -Lateral chambers with perforate walls; 4 Canal-system of
cyclical marginal cord ; 5 Tubules connecting adjacent chambers. C, Periphery and profile of same, natural
size. D, Orbitoides tenella, Giimbel. Eocene ; Kressenberg. (Natural size.) E, Orbitoides variecostata, Giimbel.
Eocene ; San Martino, near Verona. (Natural size.) F, Orbitoides ephippium, Sow. Eocene ; Kressenberg.
(Natural size.)

which are likewise disposed in concentric rings. Very abundant in the Eocene,
associated with Nummulites ; rare in Upper Cretaceous and Miocene.

Dawson, Carpenter, and various other authors have referred the so-called
Eozoon occurring in crystalline limestone of the Archaean (Laurentian) period
to the Foraminifera ; but the elaborate investigations of Mobius have shown
that neither Eozoon nor Archaeospliaerina can be regarded as organic structures,
but are mineral segregations.

Range and Distribution of Fossil Poraminifera.

Of the over 2000 species of Foraminifera that have been described, about
two-thirds are known in a fossil state. The longevity of certain genera and
species is remarkable, many of them persisting, according to Parker, Jones,
Brady, and others, throughout a number of formations of various ages.

The earliest forms occur very sparingly in the Silurian of St. Petersburg,
Siberia, and Scotland. They are for the most part poorly preserved, those
from Petersburg being recognisable only as glauconitic casts, belonging in
part to silicious shell-bearing genera (Placopsilina, Saccamina), and in part to
vitreo-perforate genera (Nodosaria, Lagem, Globigerina, Eotalia). The Devonian
is also very poor in Foraminifera remains ; but, on the other hand, the Carbon-
iferous yields an abundant and considerably varied fauna; in fact, certain
genera (Fusilina, Schwagerina, Saccamina, Endothyra) build up limestone de-

36 PROTOZOA— RHIZOPOD A CLASS i

posits occasionally of great thickness. Numerous representatives of the
Lagenidae (Nodosaria, Dentalina, etc.), Teniulnri'/ni', Eotalidae, and even the
Numrmtiinidae accompany the rock-building forms, and continue for the most
part throughout the Permian. Except in the Alps, the Triassic is almost
destitute of Foraminifera, and even the pure limestones and dolomites of the
Alpine Triassic have usually become so altered by metamorphism as to render
the recognition of tests well-nigh impossible. Notwithstanding, Globigerina
limestone has been discovered in the Upper Triassic of the Northern Alps,
and tests of Cristellaria, Marginulina, Globigerina, Textularia, BilocuUna, etc., are
found in the St. Cassian beds.

Certain argillaceous and calcareous strata of the Lias and Jura contain
vast quantities of minute, vitreo-perforate or silicious Foraminifera. In the
Cretaceous, Textularia, Eotalia, Cristellaria, Globigerina, Miliola, and Coccoliths are
essential constituents of the White Chalk. Individual beds of the Maestricht
Chalk consist almost entirely of Calcarina remains ; in the Urgo-Aptian Orb-
itolina is the chief rock-builder ; in the Upper Cretaceous Alveolina.

The maximum, development of the Foraminifera falls in the Tertiary
period. Massive beds of the Eocene Calcaire Grossier occurring in the Paris
basin and in the Pyrenees, and affording an excellent building material, are
composed of Miliolidae remains ; Other Eocene limestones consist of Alveolina, *
Operculina, Orbitolites, and Orbitoides aggregations. But of far greater geological
importance are the Nummulites, which occur in incredible abundance in the
Eocene and Oligocene Nummulites-formations of the Mediterranean district,
Asia Minor, and Eastern Asia.

During the late Tertiary the Nummulites almost entirely disappear ; only
Amphistegina continues as an occasional rock-builder, and from the middle
and later Tertiary on, the Foraminifera fauna remains very nearly the same
as now.1

1 [Additional references to the Literature on Protozoa :
Soldani, A., Testaceographia ac Zoophytographia, etc., 1789.

Fichtel und Moll, Testacea microscopia aliaque minuta ex generibus Argonauta et Nautilus, 1803.
Dujardin, F., Observations sur les Rhizopodes (Comptes Rendus), 1835.
('In /in rede et Lachmann, Etudes sur les Infusoires et les Rhizopodes, 1858-59.
Parker and Jones, Nomenclature of the Foraminifera, (Ann. and Mag. Nat. Hist.), 1858-75.
Terquem, 0., Meiuoires sur les Foraminiferes du Lias (Mem. de 1'Acad. Imp. de Metz), 1858-66.
\Vili;«mson, W. C., On the Recent Foraminifera of Great Britain, 1858.

Mutter, «/"., Ueber die Thalassicolen, Polycystinen, uud Acanthometren ( Abhandl. Berliner Akad.), 1858.
Rewss, E. A., Entwurf einer systematischen Zusammenstellung der Foramiiiiferen, 1861.
Jones, Parker, and Brady, Monograph of the Foraminifera of the Crag, 1868.
Ehrenberg, C. G., Mikrogeologische Studien iiber das kleinste Leben der Meeres-Tiefgrunde. etc.

(Abhandl. Berliner Akad.), 1872.
Zittel, If. A. von, Ueber fossile Radiolarien der obereu Kreide (Zeitschr. d. deutsch. geol.

Gesellsch.), 1876.

Leidy, J., Freshwater Rhizopods of North America (Rept. U.S. Geol. Surv. Territ. vol. XII.), 1879.
Dunibowski, E. von, Die Spongieu, Radiolarien, und Foramiiiiferen der Unter-Liasischen Schichten

von Schafburg (Deukschr. Wiener Akad.), 1882.

Brandt, K., Die kolouiebildenden Radiolarien (Sphaerozoeeu) des Golfes von Neapel, 1885.
Hdusler, R., Monographic der Foramiiiiferen - Fauna der schweizerscheu Transversarius - Zone

(Abhandl. der schweiz. palaont. Gesellsch.), 1890.
Perner, J., Ueber die Foramiiiiferen des bohmischeu Cenomans. Palaeontographica Bohemica

No. 1 (Abhandl. der k. bohm. Gesellsch. der Wissen. II. Classe), 1892.
Sherborn, C. D., Index to the Genera and Species of the Foraminifera (Smithsonian Misc. Coll. vol.

XXXVII.), 1893-95.

Very extensive bibliographies are contained in the works of Carpenter and Brady, cited on p. 19.
Reference may also be made here to the exhaustive bibliography of the Sponges, which will be found
in the monographs of Hinde and Rauff, cited on p. 42. — TRANS.].

ORDER II

RADIOLARIA

37

.Silurian

1

j

Permian

£
I

Jonssk

\

|

s

Miocene

§

I

s

"s

A., Chitinosa

B. ' Agglutinantia

Litnolidae

„

|

Orbitulinidac

!

C. Porcellanea

Nubecularidac

Peneroplidae

'"

Miliolidae

1

__

••BHB

mgglEBm

B^

•-^•^

D. Vitro-Calcarea

Lafenidac

•••

IMBl

Textularidae

Globifferinidae

Rotalidae

Fusulinidae
Xuinmulinidae

•BE

—

.........

•^^^^

1

W^B^^W

— -

Order 2. RADIOLARIA. Miiller.1
(Polycystina, Ehrenberg.)

Uhr.opoda emitting fine, filiform, radially directed pseudopodia, with
capsule and extra-capsulum, and usually with delicate silicious skeleton.

The sarcode body of the Radiolarians is differentiated into (1) an inner
« -.Mitral sphere or capsule of tough slimy protoplasm containing one or more
nuclei, vacuoles, alveoles, granules, oil-globules, and sometimes crystals, and
surrounded by a capsule-membrane perforated by pores or pylae ; and (2) an
outer jelly-like extra-capsulum. the sarcode of which emits pseudopodia. The
individuals lead usually an isolated existence, and are only rarely united in
colonies.

Must Radiolarians secrete skeletons composed either of bars or spicules of
(an organic substance allied to horn or chitin) or silica, or they build
an exceedingly delicate lattice-work composed of transparent amorphous silica.
Only the latter forms are known in a fossil state, and owing to their minute
size, are commonly indiscernible except with the aid of the microscope.

1 Khrenberg, C. G., Mikrogeologie, 1854, and Abhandlg. Berliner Akad. 1875 (Radiolaria from
Karliados). — Haeckel, E., Die Kadiolarien. Monograph 1862, and Report on the Radiolaria col-
lected l.y II. .M.S. Challenger, ISSl.—Hertwig, Ji., Der Organismus der Radiolarien, 1879.—
>'/••;///•, E., Palaeontographica, XXVI. 1878 (Radiolaria from Sicily).— 7? list, D., Palaeontographica,
XXXI. 1885, XXXIV. 1888, and XXXVIII. 1892.— Drei/er, /•'., Die Tripoli von Csiltanisetta.
Jsnaische Zeitsclirift f. Xaturw. XXIV. ISQQ.—Cayeux, L., Bull. Geol. Soc. France, 1894, p. li»7.

38

PROTOZOA— RHIZOPODA

CLASS

Haeckel divides the Radiolaria into four sub-orders, as follows : —

A. Acantharia. — Capsule-membrane uniformly perforated ; skeleton com-
posed of acanthinic spicules. Unknown in fossil state.

B. SpumeUaria. — Capsule -membrane single, pores distributed all over;
skeleton silicious, spherical, or discoidal, sometimes wanting (Fig. 48).

C. Nasselaria. — Capsule-membrane single, perforated only about the oral
pole ; skeleton silicious, helmet- or cap-shaped, conformation of poles dissimilar
(Figs. 49, 50).

D. Phaeodaria. — Capsule-membrane double, perforated by one main opening
prolonged into a tubulus, and by a few smaller accessory openings. A dark

FIG. 46.

Silurian and Devonian Radiolarians : A, Cenosphaera macropora, Riist. Ordovician ; Cabrieres, Languedoc.
L, Staurolonche micropora, Riist. Ordovician ; Cabrieres. C, Caryosphaera Groddecki, Riist. Upper Devonian ;
Schiibenliolz, near Elbingerode, Harz Mountains. D, Lithocampe Tschernytscheicii, Riist. Devonian ; Ural.
Magnified 100—120 diameters (after Riist).

pigment body (phaeodium) constantly present in extra-capsular sarcode. Skeleton
commonly consisting of hollow silicious spicules disposed in flask-shaped or
variously shaped frameworks. Unknown in fossil state.

Radiolarians are exclusively marine organisms, and are found at all bathy-
metric zones. They occur in vast numbers, especially in tropical seas,

FIG. 47.

Carboniferous, Jurassic, and Cretaceous Radiolarians : A, Stauracontium inaequale, Riist. Carboniferous ;
Sicily. B, Trochodiscus Nicholsoni, Riist. Carboniferous ; Harz. C, Xiphodictya acuta, Riist. In coprolite
from Lias ; Ilsede, Hanover. D, Hymeniastrum rolundum, Riist. In coprolite from Cretaceous ; Zilli,[Saxony.

swimming on the surface, as well as at medium and even abysmal depths ;
particularly between 2000 — 4000 fathoms in depth, extensive deposits of
" Radiolarian mud " have been found, the composition of which is largely silica
with a small percentage of carbonate of lime.

The diversity of form exhibited by Radiolarians is most astonishing, and
the identification of their microscopic silicious skeletons is impossible without

ORDER II

RADIOLARIA

39

Contrary to formerly accepted ideas, the geo-

the aid of special literature.

logical antiquity of

the Radiolarians is

very great ; and they

also play an important

part in the composi-
tion of many silicious

and calcareous-silicious

rocks (quartzites, horn-
stone, jasper, phyllites,

Aptychenschiefer,etc.)

According to Barrois

they are the oldest

known animal organ-
isms, since the Spumel-

laria (Monosphaeroidae)

occur plentifully in

the bituminous quart-
zites of Bretagne, in-

terbedded with pre-

Cambrian gneiss.

Although the group

is still very imperfectly

known, yet, according

to Rust, fossil Radio-

laria are by no means

less abundant and less

diversified than the

recent.

ceptional

(Miocene of Barbados,

Oran, Sicily) have the skeletons been preserved unaltered, and still consist of

amorphous silica. In the
older rocks the silica has
usually become dissipated
in the matrix, being re-
placed by lime carbonate,
iron, or some colouring
agent; in other cases the
quartz has become crypto-
crystalline, or replaced by
a calcite pseudomorph.

The Cambrian Griffel-
schiefer of Sonneberg in
FIG. 49. Thuringia contain poorly

Recent and Tertiary Nasselarians : A, Podocyrtis Schomburgld, Ehrbg. r»reserved Svka*roidea : the

Tertiary marl ; Barbados. B, Cyrtocalpis amphora, Haeek. Recent ; * , .^

Mrssma. C, Bothryocnmpe liexfttltalamia, Haeck. Recent; Mediter- USUallV dark, tllOUgh SOniC-

ranean. D, Petalospyrisforeolata, Ehrbg. Tertiary marl ; Barbados. ,. i , li^ht coloured

Ordovician strata of Langenstriegis in Saxony, and of Rehau and Steben in
Franconia, the red jasper of Abington, Scotland, and the Ordovician silicious

Recent and Tertiary Spumellarians : A, Actinomma asferacanthium, Haeck.
T in «v Recent; Messina. B, Stylodictya multispina. Haeek. Recent; Messina. C,
] ex- jfeiiodiscus Humboldti, Ehrbg. Barbados earth (Miocene); Barbados. D,
instances HaUomma dixiphos, Ehrbg. Miocene marl ; Caltanisetta, Sicily. E, Astromma
' Aristotdis, Ehrbg. Miocene ; Barbados.

40

PROTOZOA— RHIZOPODA

CLASS I

rocks of Cabrieres in Languedoc, are more or less rich in Radiolarian remains
belonging exclusively to the Spumellaria (Fig. 46, A, B}.

From the Devonian jasper of Siberia, the silicious schists of Hesse and
Nassau, and the "Tnanganif erous quartzite of Elbingerode in the Harz, and
other places, Riist has described forty-six Spumellarian species and seventeen
Nasselarian (Cyrtoidea). The sub-Carboniferous quartzites, phyllites, adinole,
and jaspers from the Harz (Culm formation), Ural district, and Sicily have
yielded 155 species, of which thirty-six belong to the Nasselaria. In general
the Palaeozoic Radiolarians are remarkable for their relatively large size and
excellent preservation.

The Triassic appears to be destitute of Radiolarians except in the Alps,
where they are abundant in the hornstone and silicious limestone of the
Buchenstein beds of Hungary, and occur less frequently in the Reifling lime-
stones, in the Wengen beds of Storzic in Krain, in the marls of St. Cassian,

and in the silicious lime-
stone of the Roth elstein,
near Aussee, etc. They
are usually associated
herewith the remains of
sponges and Foramini-
fera. In the silicified
coprolites of the Lias,
found at Ilsede, Han-
over, Radiolarians are

Tertiary Nasselarians from Barbados : A, Anthocyrtis mespihis, Ehrbg. B, ver7 common ; they are

in the limestones of the

Lower Lias on the Schafberg in Upper Austria. Certain hornstone beds of
Middle Jurassic age, found at Piszke, Hungary, the Upper Jurassic pudding-
stones of Cittiglio, near Laveno on Lago Maggiore, and numerous Tithonian
jaspers, as well as the Alpine Aptychus beds, are charged with Radiolarians ;
here the Nasselaria are nearly as plentiful as the Spumellaria. The Lower
Cretaceous (Neocomian) of Gardenazza has yielded but few forms ; but, on the
other hand, coprolites from the Gault, found near Zilli in Saxony, and Lower
Cretaceous clay marls in Manitoba, Canada, as well as the Upper Cretaceous
marls of Haldem in Westphalia, and Vordorf in Braunschweig, contain
excellently preserved skeletons in greater or lesser abundance. Even the
flinty concretions of the Upper Chalk sometimes contain them, although in a
poor state of preservation. Certain Eocene hornstones in Italy, according to
Pantanelli, are filled with Radiolarian remains, while in the Flysch they are
also very profuse in some localities, although usually poorly preserved.

By far the most noted occurrence of fossil Radiolarians is in the chalky
"Barbados earth," of Miocene age, in which Foraminifera'are also very con-
spicuous ; while the " tripoli " of Grotte, Caltanisetta, and Girgenti in Sicily,
of Oran, Aegina, Zante, the Nikobar Islands, and other localities (Miocene and
Pliocene), is scarcely less noteworthy. Ehrenberg has described 278 species
from Barbados alone, and from Sicily Stohr has described 118 species, most of
which belong to still extant Spumellarian, Nasselarian, and Phaeodarian genera.

FlQ 50

Sub-Kingdom II. COELENTERATA. (ZOOPHYTES)

COELENTERATES or Zoophytes are free-swimming or attached aquatic animals of
very variable form and size, with multicellular bodies, and more or less distinctly
radial in symmetry. A large-sized mouth-opening conducts into a central gastric
cavity (gaxtrovascular space), which either ends blindly, or is provided with peri-
pheral pouches, or a canal-system for the conveyance of food-particles. Since
the chief function of the gastrovascular space, together with its diverticula, is
that of digestion, although including also the reproductive organs, it corresponds,
at least physiologically, to the stomach and intestines of higher animals. A
definite anal opening is absent ; the excretions and sexual elements are voided
through the mouth.

The body consists of three layers of cells, an ectoderm, mesoderm, and
entoderm. The ectoderm often secretes a calcareous or horny skeleton, but in
most cases the horny, silicious, or calcareous skeletal elements are the product
of the mesoderm.

Reproduction is either sexual or asexual, or an alternation of generations
may occur. The process of budding or self-division gives rise to polyzooid
colonies, in which the individuals subsist in intimate relationships with one
another, and sometimes institute a physiological division of labour.

R. Leuckart was the first to recognise the Coelenterates as constituting a
distinct structural type of animals, and separated them from the Echinoderms,
with which the older systematists had associated them under the general term
of Radiates or Actinozoa. The Coelenterates are divided into three principal
groups or sub-branches : Porifera, Cnidaria, and Ctenophora ; of which only the
first two have left traces in the rocks.

SUB-BRANCH I. Porifera. Hogg.

The Porifera or Sponges are sessile, aquatic animals of extremely variable
form. The body consists of a single layer of pavement- cells forming the
ectoderm, a likewise single layer of collared epithelial cells constituting the
entoderm, and a strongly developed mesoderm tissue, which latter comprises the
bulk of the soft parts (including all the organs, muscles, sexual elements, and
nerves), and almost invariably secretes a hard skeleton. The latter may consist
of horny sponge-fibres, or of regularly disposed silicious or calcareous skeletal
elements. The whole body is ramified by a canal -system, and the outer
epithelial layer is perforated by countless, minute, dermal pores for the entrance

42 COELENTERATA— PORIFERA SUB-BRANCH i

of water laden with food-particles. The pores communicate by means of fine
incurrent canals with sub-dermal ciliated chambers, from which larger excurrent
canals conduct the water and sponge-food through the body, and generally open
into a wide, exhalent opening called the cloaca or paragaster. Stinging cells,
tentacles, and radial mesenteries are absent. The Porifera comprise but one
class — the Sponges.

Class 1. SPONGIAE. Sponges.1

Sponges are remarkable for their extreme variability in external form and
size ; they lead either an isolated existence, or are united in colonies of
cylindrical, tubulate, pyriform, fungus-like, bulbous, spherical, compressed, leaf-
like, umbel-, bowl-, or beaker-shaped, or of botryoidal form. They are long or
short stemmed, or a peduncle may be absent ; sometimes the stock is branching,
and the arms may be either separate or interlaced so as to form networks.
Nothing is less stable than the outer conformation, which varies excessively
according to the situation and other physical conditions, and whose systematic
importance, accordingly, is very slight. The size is also extremely variable,
ranging from that of a pin-head to 1 J metres in diameter.

Sponges are invariably sessile in habit, being attached either by means of a
stem or a bundle of anchoring spicules, or they may be simply encrusting at
the base.

The canal-system, by which the whole body is traversed, is extremely com-
plicated in thick-walled, but simple in thin-walled sponges. A distinction is
recognised between incurrent or inhalent, and excurrent or exhalent canals.2
The water enters through the dermal pores, and passes through the incurrent
canals into the ciliated chambers, which are lined with epithelial cells. From
these it is conveyed through all parts of the body by means of the frequently
branching excurrent canals, which open into a sac-like, tube-like, or funnel-
shaped cloaca. The exhalent opening of the latter is termed the osculum.
Extremely thin-walled sponges have no cloaca, osculum, or branching canal-

1 Literature : A. On recent Sponges.

Schmidt, 0., Die Spongien des Adriatischen Meeres, Leipzig, 1864-66.— Die Spongien des
Meerbusens von Mexico, Jena, 1879-80.— Haeckel, K, Die Kalkschwamme, 1872,—Schulze, F. K,
Untersuchungen iiber den Ban und die Entwickelung der Spongien ; Zeitschr. fur wissenschaft. Zool.,
Bd, XXVII., XXVIII., XXX., 1876-80.— Report on the Hexactinellida ; Sci. Results Challenger
Exped., Zoology, vol. XXI. 1887.— Vosmaer, G. O. J., Porifera ; Bronris Classen und Ordnungen des
Thierreichs (2nd ed.), Bd. II. 1882-87.— Lendenfeld, Jl. v., Das System der Spongien ; Biolog.
Centralblatt, Bd. IX. 1889.— A Monograph of the Horny Sponges, London, 1889.

B. On fossil Sponges.

Goldfuss, A., Petrefacta Germaniae, Bd. I. 1826-33.— Michelin, H., Iconographie zoophytologique,
1840-47. — Fromentel, E. de, Introduction a 1'etude des eponges fossiles ; Mem. Soc. Linn. Normandie,
vol. XI. 1859. — Moemer, F. A., Die Spongitarien des norddeutschen Kreidegebirges ; Palaeonto-
graphica, Bd. XII. l&(M.—Zittel, K. A., Ueber Coeloptychium ; Abhandl. k. bayer. Akad. Bd. XII.
1876.— Studien iiber fossile Spongien, I., II., III., ibid. Bd. XIII. 1877 (translated by Dallas in Annals
and Magazine of Nat. Hist, for 1877, 1878, 1879).— Beitrage zur Systematik der fossilen Spongien,
I., II., III.; Neues Jahrb. fur Mineral. 1877, 1878, 1879.— Quenstedt, F. A., Petrefactenkunde
Deutschlands, Bd. V. l877.—Sollas, W. «/., Quart. Journ. Geol. Soc. vol. XXXIII. 1877, and XXXVI.
1880. — Hinde, G. J., Catalogue of fossil Sponges of British Museum, London, 1883. — Monograph of
British fossil Sponges ; Palaeontographical Society, 1887, 1888, 1893.— Ran/, H., Palaeospongio-
logia ; Palaeontographica, Bd. XL. 1893.

'-' [In the terminology proposed by Rauff (torn, cit.\ inhalent canals are designated as epirrhysa,
and exhalent canals aporrhysa ; the former terminate on the periphery in ostia (not to be confounded
with the finer dermal pores), while the latter terminate on the cloacal surface in postica (again not
to be confounded with gastral pores). Postica are usually larger than ostia, and differ from them in
form and arrangement. — TRANS.]

CLASS I

SPONGIAE 43

system, but the excurrent canals terminate directly in small openings situated
on the upper surface of the body. The cloaca when present is often of
considerable depth, although sometimes shallow, or reduced to a mere sac-like
prolongation of the osculum. Forms with a large and deep cloaca are regarded
as single individuals, those with numerous cloacae and oscula as colonies. I Jut
since all the cloacae of a colony communicate by means of canals, while the
oscula are never surrounded by a crown of tentacles, it is often difficult to
distinguish between large excurrent canals and true cloaca, and hence also
between individuals ami colonies.

In the first process the fertilised

ova comprete^aTtolerably regular segmentation, develop into a gastrula, pass out
through the osculum, and attach themselves to some foreign object. Asexual
reproduction takes place_by_budding, the young buds remaining attachecfTicftire
parent individual, andthus giving rise to colonies. Reproduction by means of
fission is of rare occurrence.

The great majority of sponges secrete a skeleton composed either of horny
fibres or of silicious or calcareous spicules, or they incorporate foreign bodies
into their framework. Only a few recent forms (Myxospongiae) are with-
out a skeleton. In the horny sponges (Ceratospongiae) the skeleton consists
of anastomosing and reticulated fibres of spongin, an organic nitrogen compound
resembling silk. The fibres are either solid, or they contain an axial canal,
which is sometimes cored with foreign bodies, such as sand-grains, fragments of
sponge-spicules, Foraminifers, Radiolarians, etc.

Silicious spicules are sometimes encased in horny fibres, sometimes occur
detached in the cellular tissues, or are interwoven and consolidated with one
another in various ways to form scaffoldings. In each genus the skeleton is
composed of but a single form, or at the most of but a few regularly repeated
varieties of silicious bodies, which are called the skeletal elements. In addition
to these there occur more or less abundantly, especially on the outer surface
and in the cloacal and canal walls, extremely delicate flesh-spicules, usually of
small size and of great diversity of form. The flesh-spicules are as a rule
destroyed during fossilisation. All the silicious skeletal elements are secreted
by nucleated cells, and are composed of concentric layers of colloidal silica,
deposited usually about a slender axial canal. In some spicules, notably those
having spherical or stellate contours, the axial canal is wanting. It is very
delicate in fresh spicules, but becomes enlarged by maceration, and in fossil
specimens it is often coarsely calibrated.

The multitudinous varieties of silicious skeletal elements (Fig. 51) are
resolvable into a few fundamental types, as follows : —

\^> (a) Uniaxial spicules or Monaxons (Fig. 5 11"10 and 14-16). Straight or
bent, smooth, prickly or knotty, bevelled, sharpened or truncated needles, rods,
hooks, clasps, pins, and anchors (amphidisrs). They invariably contain an axial
canal, which may be either entirely sealed up, or open at one or at both ends.

(b) Tetraxial spicules or Tetraxons (Fig. 5 117). The normal form is
characterised by four equal rays intersecting like the bisectrices of the plane
angles of a regular tetrahedron. Triaxial forms result from the occasional
abortion of one of the rays. One of the rays may become elongated or other-
wise modified so as to form anchors (triaens) with three simple or furcate hooks
(Fig. 5 118~23). Three of the rays may be numerously divided or foliately
expanded so as to produce forms resembling thumb-tacks (trichotriaens, phyllo-

44

COELENTERATA— SPONGIAE

CLASS 1

; atrophy of the fourth ray in the last-named form reduces the spicule
to a delicate silicious disk (Fig. 5 128). A peculiar forking of the shaft gives
rise to candelabras or amphitriaens, while other modifications may produce
umbel-like spicules (Fig. 5 1'26), etc.

Certain skeletal elements of the Lithistids (Figs. 53-68) may be regarded
as irregular tetraxons (desmoms), in which the extremities of the four rays are
prolonged in knotty, root-like excrescences, or in which, owing to the un-

Fio. 51.

Various forms of Sponge spicules from the Upper Cretaceous of Haldevn, Westphalia ; magnified 25 diameters.
!—•:>, Uniaxial rods and needles. 7—0, Uniaxial silicious elements with coarse axial canals. 10—13, Uniaxial
cylinders and spheres. 14, Microspined spicule. 15, Clasp-hook flesh-spicule. 16, Bispatulate fleah-spicnla.
17, Regular four-rayed spicule (chevaux de frise). 18—21, Trifid anchor-shaped spicules. 22—23, Anchors with
furcate head-rays. 24—25, Irregular four-rayed skeletal elements. 20, Umbel-shaped spicule. 27, Six-rayed
spicule. 28, Po'lyaxile silicious disc.

symmetrical growth, branching, or atrophy of one or more of the arms, extremely
irregular forms are produced ; for these a special terminology has been devised
by Rauff.

(c) Hexactinellid spicules (Hexactins or Triaxons) (Figs. 69-74). The ground-
form is an axial cross with six equal arms intersecting at right angles like the
axes of a regular octahedron. Atrophy of one or more of the rays may result
in pentaxial, tetraxial, triaxial, or even nail-shaped forms, without their real
character becoming entirely obliterated. Bifurcation or other modifications of
a number or all of the rays produce those exquisite silicious structures so
characteristic of the group Hexadinellida, which resemble candelabras, double-
headed anchors, fir-trees, pitch-forks, rosettes, etc. The fusion of juxtaposed
hexactins produces more or less symmetrical latticeworks with cubical interstices.

('/) Anaxile or polyaxile bodies of spherical, cylindrical, stellate, or discoidal
shape, which are not derivable from either of the three ground-forms, occur in
only a few varieties of recent and fossil silicious sponges.

Calcareous skeletal elements are much less complicated, and are generally
smaller and more perishable than the silicious. Their form is either triaxial
(triads), tetraxial (tetraxons), or nail-shaped (monaxons). The triaxial and

ORDER i SILICISPONGIAE— MONACTIXELLIDA 45

tetra.xial spicnles an- very rarely forked or otherwise modified. Kach skeletal
(•lenient behaves optically like a single ealeite crystal : axial canals are absent.

The skeletal dements in spunk's are arranged chielly with reference to the
circulation of water tlmm-h the canal systems. In thin-walled forms they are
more or less closely crowded together, and are often regularly oriented in the*
soft parts; in other forms they are encased in horny filires, or are packed in
b»-t \\eeii the canals ; in still others they are united to form an irregular frame-
work, or may be soldered together in a regularly reticulated scaffold iii.u.

The hornv til>res are totally destroyed during fossilisation ; calcareous
spicules are often wholly or partially dissolved, or are replaced by infiltrating
lime carbonate, and assume a dense fibrous appearance (Pharetrones). In
silicious sponges also the skeletal elements are rarely preserved unaltered ; as
a rule the originally colloidal silica becomes crystalline, or is dissolved and
carried away. The cavities thus formed may subsequently become tilled with
infiltrating quartz, limonite, or most commonly with carbonate of lime. In
this manner the skeletons of fossil silicious sponges are converted into calcite,
and, contrariwise, spicules that were originally calcareous may become silicified.
Hence the distinction between silicious and calcareous sponges in the fossil
state depends entirely upon morphological characters, and not at all upon the
chemical composition of the preserved parts.

Sponges are divided into four sub-classes : — Myxospongiae, Ceratospongiae,
S&icispongiae, and Calcispongiae. The latter group stands in sharp contrast to
the other three, which are connected by intermediate forms, and constitute
to- ether a group of equal value with the calcareous sponges. Skeletal elements
are absent in the Mi/xospongiae, whose bodies are composed entirely of soft
cellular tissues. The Ceratospongiae also lack imperishable hard parts, the
spongin fibres being entirely destroyed during fossilisation. The reputed horny
sponges from the Trias (Wiizocorallum), Jurassic, and Cretaceous (Spongites,
Saxonicus, Paramudra, etc.) are either of inorganic nature, or are zoologically
indeterminate. All fossil sponges, therefore, belong either to the Silicispongiae
or the Calcispongiae. The oldest forms are found in the Cambrian; in the
Trias, Jurassic, and Cretaceous they are very abundant.

Sub-Class 3. SILICISPONGIAE. Silicious Sponges.

Skeleton composed either exclusively of silicious elements, or of horny fibres enclos-
ing silicious spicules.

Order 1. MONACTINBLLIDA. Zittel.

(Monaxonia, F. E. Schulze.)
All skeletal elements uniaxial.

The Monactinellida include the majority of existing marine sponges, most of
which occur at moderate depths ; and also the few fresh-water forms (Spongilla)
that are known. The skeleton, as a rule, is composed like that of the horny
sponges, of anastomosing spongin fibres, which either encase rod-like spicules,
or contain quantities of uniaxial silicious elements ; sometimes the latter are
also present in the soft parts. In each genus there are generally but one or
but a few varieties of silicious elements present, which are uniformly dis-

46

COELEN TER AT A— SPONGI AE

CLASS I

tributed throughout the body. Needles, hooks, crotchets, cylinders, spindles,
amphidiscs, and the like occur in great diversity. Owing to the decomposition
of the horny fibres during fossilisation, and the fact that the skeletal elements
are never soldered together, the latter become detached and strewn in all
directions. While Monactinellid spicules are very common in certain forma-
tions, they are rarely united in the form of coherent skeletons, and are only
capable of generic determination when possessing characteristic forms (Remeria,
Esperia, etc.) The lowermost members of the Alpine Lias often contain
considerable hornstone, and are sometimes completely filled with rod-shaped
spicules. In various Cretaceous and Tertiary horizons also Monactinellid
spicules are enormously abundant. Hinde has described a Climacospongia from
the Silurian of Tennessee, in which the skeleton consists of spicules arranged in
longitudinal rows, and connected by transversely disposed elements. The
spicules were probably originally enclosed in horny fibres. The Clionidae
secrete pin-shaped silicious elements which are also encased in horny fibres,
and by means of which they bore labyrinthic passages in the shells of mollusks.
Fossil sponge -borings are also common. Detached spicules of Renieria,
Axinella, and Haplistion have been described by Hinde from the English Car-
boniferous Limestone.

Order 2. TETRACTINELLIDA. Marshall.
(Tetraxonia, F. E. Schulze.)

Skeleton composed of regular tetraxons which are generally combined with uni-
axial, polyaxile, or heteraxile silicious bodies. The skeletal elements occur detached

throughout the soft parts, and are never united to
form a connected framework.

The most common forms of skeletal elements
are normal tetraxons, anchors with simple or
furcate prongs, spheres, and stellate bodies. In
certain genera (Geodia) the large anchors and
cylinders are disposed in radiately arranged
fascicles, and are surrounded by a thick layer of
anaxile spheres.

Detached Tetractinellid spicules associated
with Monactinellids occur more or less abundantly
in the Carboniferous Limestone, the Alpine Infra-
Lias, the English Neocomian, the Deister Sand-
stone (Hils), the Upper Cretaceous of Haldem and
Coesfeld in Westphalia, and in the Tertiary and
Pleistocene formations. The skeletal elements
are preserved in their natural position in the
Tethyopsis, Zittel (Fig. 52); and PacJiastrella,

FlG- 52-

genera Ophiraphidites, Carter
Schmidt.

Order 3. LITHISTIDA. Schmidt.

Massive, thick -walled, silicious sponges, usually with complicated canal -system.
Skeleton composed of irregular tetraxons or monaxons (desmoms), which develop knotty
or root-like branches either at the extremities or all along the shaft, and are firmly

ORDER in SILICISPONGIAE— LITHISTIDA 47

united by zygosis. Symmetrical, tetraxial, uniaxial, or polyaxile dermal and flesh-
spicules also present.

The Lithistids are closely related to the Tetractinellids, and, in the opinion
of many zoologists, constitute with them but a single order.

The Lithistids are peculiarly well suited for preservation, owing to the
massive, stony character of their skeletons ; and their remains occasionally form
thick deposits, especially in the Jurassic and Cretaceous. Their outer configu-
ration is extremely variable ; most commonly it is bowl-shaped, cup-shaped,
pyriform, globular, bulbous, or plate-like ; while the body is attached either by
the base or by means of a peduncle. The canal-system varies greatly in different
genera, but is usually well developed and more or less complicated. The four-
rayed skeletal elements are interlocked by means of the root-like branching ends
of the rays, and the points of intersection (nodes) with the ends of adjacent
uniaxial spicules are thickened into balls. The uniaxial, usually very irregular
skeletal elements are interlaced on all sides by means of root-like processes.
Dermal and flesh-spicules are preserved only under exceptionally favourable
conditions, but are invariably present in recent genera, and furnish valuable
systematic characters. The classification of fossil Lithistids is based wholly
upon the skeletal elements and canal -systems. Five principal groups are
recognised, whose subdivision into families need not concern us at present : —
Tetracladina, Eutaxicladina, Anomocladina, Megamorina, and Ehizomorina. Exist-
ing Lithistids occur most abundantly at depths ranging between 100 and 400
metres, but are occasionally found as deep as 1800 metres.

Sub-Order A. TETRACLADINA. Zittel.

Skeletal elements composed of four usually equal rays, each of which encloses
axial canal, and has extremities terminating in root-like strands or processes;
spicides are intertwined
to form an open mesh-
work. Dermal spicules
either grapnel - like te-
traxons, frequently with
furcate prongs, or dis-
coidal with entire or
lobate margin; or they
are nail - shaped or
, cylindrical monaxons.

The skeletal ele-
ments of the Tetracla- FIG. 53.

dina are Usually SVm- Aulocopium auvuitium, Oswald. Diluvium; Sadowitz, Silesia, a, Indi-
, . , vidual in !/.-> natural size ; 6, Skeleton magnified GO diameters.

metrical tetraxons,

whose four smooth, more rarely tuberculate or knotty rays intersect approxi-
mately at an angle of 109£°. They occur in the Cambrian and Silurian,
are very scarce in the Upper Jurassic (Protetraclis), but common in the
Cretaceous, Tertiary, and Recent periods.

Aidocopium, Oswald (Fig. 53). Hemispherical or bowl-shaped with short
peduncle ; inferior surface covered with dense, wrinkled, silicious skin. Cloaca
central ; sponge body with numerous arched canals parallel to contour of peri-

48

COELEN TEE ATA— SPONGI AE

CLASS I

phery, and with, finer radial canals leading from exterior to cloaca. Skeleton
composed of irregular smooth -rayed tetraclons with root-like branching

FIG. 54.

Callopegma acaiile, Zitt. Senonian ; Ahlten, Hanover ; a, Individual in 2/4 natural size ; fe, Skeleton mag-
nified 40/i 5 c> Portion of periphery, 2/i ; d, Same magnified 40/j, and showing anchors with furcate head-rays.

extremities, disposed in rows parallel to the radial canals. Occurs (usually
replaced by calcite) in the Ordovician of the Eussian Baltic Sea Provinces,

FIG. 55.

Phymatella tulerosa, Quenst. sp. Quadratenkreide
(Upper Senonian) ; Linden, near Hanover, a, Sponge,
1/2 natural size; 6, Outer surface, 1/1 5 c, Skeletal
element, so/j ; d, Spicules from stalk portion, 50/j.

Siphonia tulipa, Zitt. Greensand ; Blackdown."
A, Longitudinal section, natural size. B, Sponge with
peduncle and root, 1/2 natural size (after Sowerby).

Ordovician of Illinois, and Silurian of Gottland. Also in erratic blocks on the
plains of Northern Germany, usually chalcedonised. »

Archaeoscyphia, Hinde. Cambrian.

Callopegma, Zittel (Fig. 54). Bowl- or funnel-shaped, short-stemmed, thick-
walled. External surface perforated by smaller, internal by larger canal-openings
(ostia and postica). Skeleton composed of smooth-rayed tetraclons, the digitate
extremities of Avhich are inflated into balls. Dermal spicules in the form of
anchors and rods. Upper Cretaceous.

Phymatella, Zittel (Fig. 55). Upper Cretaceous.

ORDER III

SILICISPONGIAE— LITHIST IDA

40

Siphonia, Park. (Fig. 56). Fig-, pear-, or apple-shaped, with long or short
p.-dunele. IJody with deep cloaca, into which arched canals running parallel
with the periphery, together with numerous fine radial canals, conduct.
Skel.-tMi. composed o! smooth-rayed, branching dichotriders. Dermal spicules

Fie. 58.

Skeletal element of Jerea
Quenstedti, Zitt., showing
branching extremities of
rays. Quadratenkreide ;
Linden, near Hanover, *Yi.

l-'i<;. 59.
I'liiitliaxi'Uii siiimniiiMt, Zitt.

Skeleton magnified SO diamet.-ix.
Senonian ; Ahlten, Hanover.

iiiu

i i>!ir!f<innix, Lamx.
Greensand; Kelheim,
Mavaria. i/o natural size.

in the form of mon-
axons and grapnels.
Abundant in Middle
and Upper Cretaceous.

Ilnllirhoa, Lamx.
Like the preceding, but
invariably short -stem-
med. Body pyriform
and lobate, owing to a
numl)er of deep con-
strictions. Cenomanian.

Jcrea, Lamx. (Fig.
57). Body pyriform,
flask-shaped or cylindrical, with truncate or depressed summit, in which a
iiinnlxT of tube-like canals, vertical in the central portion but arched in the
peripheral, terminate. Crossing the latter are finer radial canals. Skeleton
minpiised of tetraclons and dichotriders. Common in Middle and Upper
Cretaceous.

J'oli/jerea, From., Astrocladia, Thecosiphonia, Calymmatina, Zitt., Turonia, Mich.,
Plintlwsella, Zitt. (Fig. 59). Cretaceous. Discodermia, Boc., filiacodiscuki, Zitt.,
etc. Cretaceous and Tertiary.

Rhagadiwa, Zittel (Fig. 60). Ear-, plate-, or bowl-shaped, short- stemmed
Both surfaces traversed by irregular branching furro\vs, in which the canal-
icular ostia are situated. Skeletal elements four-rayed, sometimes uniformly
•VOL. i E

FIG 00.

niifni. Ituriii. s]i. Sciioiiian ; Aliltfii, Hanover, f, S
- '.-; natural si/<> ; //, Skeleton, -»o/j ; c> Lobiite disk from dermal layer, *' ,
</, Spicule of dermal layer, 40/j.

50

COELEXTERATA— SPONGIAE

CLASS I

or only distally covered with tuberculous knobs, and with digitate extremities.
Dermal spicules in the form of six-lobed disks provided with a short shaft, and
minute, multifid tetraclons. Upper Cretaceous.

Sub-Order B. EUTAXICLADINA. Rauff.

Skeleton composed of four-rayed spicules with three equally developed simple or
bifurcate rays which terminate distally in root -like fibres; and one foreshortened,
inflated fourth ray (ennomolcon). Axial canals probably in all of the rays. Skeletal

FIG. 61.

Astylospongia praemorsa, Goldf. sp. In erratic from Mecklenburg, a, Sponge, partially cut into, natural size ;
5, Skeleton, 12/j ; c, Portion of same highly magnified.

elements invariably arranged in either parallel or alternating rows, and united by
zygosis into a network with triangular or irregular meshes ; spicular nodes greatly
inflated.

Nearly all the genera are Silurian ; a few (Mastosia, Lecanella) occur in the
Upper Jurassic.

Astylospongia, Roem. (Figs. 61, 62«). Spherical, with shallow depression on
the summit ; base evenly rounded, unattached ; probably fastened by means of

anchoring fibres. Large-sized canals directed
parallel to periphery in the outer portion of the
body, vertical in central portions ; besides these
are numerous fine radial canals which termin-
ate in pores all over the periphery. Skeletal
elements with four smooth elongated rays, one
or all of which branch dichotomously just
above the junction with the shorter arm.
Spicular nodes thickened into large knots.
Ordovician of the Russian Baltic Sea Pro-
vinces, and Silurian of Sweden and North America (notably in Tennessee),
usually chalcedonised. Also in erratics in the Diluvium of Northern Germany.
Caryospongia, Carpospongia,, Rauft'. Ordovician and Silurian ; Europe.
Palaeomanon, Roem. (Astylomanon, Rauff). Like Astylospongia, but bowl-
shaped, with shallower and wider cloacal depression. Entire surface covered
with pores. Silurian ; North America. P. cratera, Roem.

Caryomanon, Carpomanon, Rauff. Silurian ; North America.

PIG. 62.

a, Detached skeletal element of A stylo
xpmiifirt,, 120/i ; b, Detached skeletal
of Hindia, 80/1 (after Hauft').

element

ORDER III

SILICISl'OXCJTAE— LITHISTIDA

61

iMuiran ( Fiii. Hi'//). Body spherical, with perforate periphery,
..f attachment wanting. All canals radiate from the centre outward.
Skeletal elements composed of three simple rays heset with prickly tubercles,
and a n-dii.-.-d l.iit ton-like fourth arm. All spicules regularly disposal in rows
parallel with radial canals. Silurian ; North America.

Sub-Order C. ANOMOCLADINA. Zittel.
(Didymmorin a, Rauflf. )

dements composed of short, smooth rays ivith spherically inflated ends
i/ in- a ff three, four, or more simple or digitate branches; the latter are united
with processes of adjacent rays ; axial canals simple. Dermal spicules
,-••,/. slmji,, I nmnaxons. Upper Jurassic and Recent.

<'i/liiiiln>i>/i i/ma, Zitt. (Fig. 63). Body cylindrical, thick-walled, attached;
cloaca wide and tube-like, receiving numerous radial canals, and extending

FIG. 63.

•'/•• '/'I* i/iiin iiiilli-iiitrntii, (H)lilt'. sj>. I'lipcr Malm; Horhst riiss. A, Two individuals, I/., natural siz»-.
/.'. Skt-li-toii magnified 30 diaiuctrrs. < '. Di-tachcd skeleUil element of Cylindrophyma, 60/x (after Kauft').

down as far as the base. External surface perforated by fine ostia. Common
in I'ppcr Jurassic. 2'b!cs

Mi-/i>iir/l<i, Xitt. Skeleton apple-shaped or hemispherical, with broad base,
or provided with very short peduncle ; base covered with wrinkled silicious
skin. Cloaca deep, funnel-shaped. Coarser canals arched, parallel with peri-
phery ; finer incurrent canals radially directed. Upper Jurassic. M. radiata,
^Hi-list, sp.

Sub-Order D. MEaAMORINA. Zittel.

( //// abdomorina, Rauff. )

Usually large-sized, elongated, smooth, lent, loosely interl<>d-in<t, Irregularly branch-
i. ;/. or only terminally forked skeletal elements with simple axial canals ; interspersed
among which small, radicifoi-m, numerously branching elements (rhizomorins) are
occasionally present. Dermal spicules uniaxial or grapnel -shaped. Ordovician.
Silurian, Carboniferous, Jurassic, Cretaceous, and Recent.

52

COELENTERATA— SPOXGIAE

CLASS I

Doryrhrma dichotoma, Roem. s

FIG. 04.

Upper Cretaceous,

a, Sponge, natural size ;

. sp. , , ,

Dermal layer, -'/! : c, Bundle of skeletal elements, !«/! ; d, Skeletal element and
several dermal spicules with furcate, anchor-shaped head-rays, 3<>/j.

Saccospongia, Rauff. Silurian. Megalithisia, Zitt. Upper Jurassic ; Nattheim.

Donjderma, Zitt. (Fig. 64). Sponge-body cylindrical, simple or branching,

pyriform or compressed, with a number of larger canals running parallel

with the body axis, and numerous smaller radial canals. Skeletal elements

large, bent, and
divided into two
or more simple
branches. Dermal
spicules in the
form of three-
fluked anchors.
Upper Cretace-
ous ; Northern
Germany, Eng-
land, and France.
According to
Hinde, also Car-
boniferous.

C art er ella,
Zitt. Cretaceous.
Isorhaphinia,
Zitt. Sub -cylin-
drical, pedunculate, with wide cloaca reaching nearly to the base. Skeletal
elements large, slightly bent, rod-shaped, inflated at the ends, rarely dichoto-
mously branching. They are associated in bundles, and so interlocked at their
extremities as to form an open meshwork. Cretaceous. /. texta, Roemer sp.

Sub-Order E. RHIZOMOEINA. Zittel

Skeletal elements small, composed of four or of three principal rays, or simple and
irregular, with numerous projecting spines or tubercles ; axial canal simple or branching.
Dermal spicules monaxons, tetraxons, or similar to those of the skeleton. Chiefly
Jurassic, Cretaceous, and Recent.

1 Nipterella, Hinde. Cambrian.

Cnemidiastrum, Zitt. (Cnemidium, p. p. Goldf.), (Fig. 65). Turbinate or bowl-
shaped, with deep cloaca. Walls thick, perforated by numerous radial canals
disposed in tiers one over another, thus forming vertical fissures which often
divide toward the exterior. Skeletal elements irregularly branching, entirely
beset with blunt, spiny processes. Abundant in the Upper Jurassic Spongiten-
kalk of South Germany, the skeletons being almost invariably replaced by
calcite. C. rimulosum, Goldf. According to Hinde also present in the
Carboniferous Limestone of Ireland.

1 1 i/alotragos, Zitt. Bowl-, plate-, or funnel-shaped, with short peduncle.
Depression in summit perforated by the ostia of numerous short canals. Ex-
ternal surface finely perforate, or covered by a smooth or wrinkled dermal layer.
Skeletal elements irregular, with numerous branches beset with points, but with few
spines. Very abundant in Upper Jurassic Spongitenkalk. H. patella, Goldf. sp.

Platychonia, Zitt. Leaf- or ear-shaped, irregularly undulating, covered on
both surfaces with fine pores. Skeletal elements resembling those of Hyalo-
tragos. Upper Jurassic. P. vagans, Quenst. sp.

OUDKll III

SILICISPONGIAE— LITHISTIDA

Jereica, Zitt. (Fig. 66). Sponge cylindrical, turliinate, pyrifonn, or club-
shaped, with short peduncle. Summit truncated or with shallow depression,
perforated by the postica of vertical ••xi-urn-nt canals. Exterior perforated by

FIG. 65.

Cnemidiastrum stellatum, Goldf. sp. Upper Jurassic Spongiten-
knlk ; Hossingen, Wiirttemberg. a Sponpe, J /2 natural size ; b, Ver-
tical tangential section, showing radial canals in vertical clefts;
e, ^keletiil elements, 60/j.

FIG. 66.

Skeleton of Jereica polystoma,
Roem.sp. Upper Cretaceous; Ahlten,
Hanover. *>°/i.

ostia of the finer radial incurrent canals. Skeletal elements root-like, bent,
irregularly branching, with numerous short lateral processes. Upper Cretaceous.
./. polystoma, Roem. sp. ; /. punctata, Goldf. sp.

Cheiu'ii<l<>i>i)r<i, Lamx. (Fig. 67). Goblet-, funnel-, or bowl-shaped, with

Chenend<>i>omfunrjifonnis, Lamx. Senonian ;
Chatellerault, Touraine. 1/3 natural size.

FIG. 68.

Verruculina auriformis, Roem. sp. Quadi-aten-
kreide ; Linden, near Hanover. -/;t natural'size.

peduncle. Cloaca deep, perforated by postica of fine canals. Skeletal
el en in its numerously branched, and containing branching axial canal. Upper
Cretaceous.

Veiruculina, Zitt. (Fig. 68). Foliate-, funnel-, ear-, or bowl-shaped, short-
stemmed or sessile. Ostia on the upper surface surrounded by slight, collar-like
elevations. Middle (Gault) and Upper Cretaceous.

54 COELENTERATA— SPONGIAE CLASS i

Amphithelion, Zitt. Like the preceding, but with both ostia and postica
terminating in bosses. Cretaceous.

Other genera : Scytalia, Coelocorypha, Stachyspongia, Pachinion, Seliscothon, Zitt.
etc., in the Middle and Upper Cretaceous.

Order 4. HEXACTINELLIDA. O. Schmidt.
(Triaxonia, F. E. Schulze.)

Silicious sponges with six-rayed skeletal elements, the rays being normally disposed
in three axes intersecting at right angles, and containing axial canals ; elements either
detached or fused together so as to form a lattice-like mesh. Dermal and flesh spicules
exceedingly variable in form, but invariably six-rayed.

Next to the Lithistida, the Hexactinellida are the most abundant of the fossil
silicious sponges. They are extraordinarily variable in form, and are often
anchored by a tuft or " rope " of long, slender, glassy fibres, or are attached
directly by the base. The walls are thin, as a rule, and enclose usually a wide
cloaca ; the canal-system is consequently much simpler than in the Lithistida,
being made up merely of short tubes which penetrate the walls more or less
deeply on both sides, and generally end blindly. Sometimes the sponge is
entirely composed of thin-walled tubes which twine about one another irregularly
and produce a system of lacunar interstices (intercanals) of greater or lesser size.

The skeletal elements proper are distinguished by their considerably larger
size and uniform type of structure, from the usually minute, astonishingly
variable and delicate flesh-spicules ; the latter, unfortunately, are very seldom
preserved in the fossil state. The skeletal elements occur detached in the soft
parts in the Lyssacina group, or they are but partially or irregularly cemented
together ; in the Dictyonina group, on the other hand, the skeletal elements are
regularly united in such manner that the rays of proximate elements are all
closely applied against one another, and are surrounded by a continuous silicious
envelope. In this way a more or less symmetrical lattice-work with cubical
meshes is produced, in which, however, the fusion of juxtaposed elements is
indicated by the fact that each ray contains two distinctly separated axial
canals. The junction of the rays at the central node of each element is usually
inflated, but is .sometimes sculptured in such manner as to enclose a hollow
octahedron (lantern nodes, lychnisks). The exterior of the skeleton is often
covered by a dermal' layer composed of irregular hexactins, in which the externally
directed ray has become atrophied ; or a dense silicious envelope is secreted, in
which stellate hexactins with reduced outwardly and inwardly directed rays
(stauractins) are embedded in greater or lesser profusion.

The Hexactinellida of the present day are distributed chiefly over the greater
depths of the ocean beyond the hundred fathom line (200 to 3000 fathoms).
They occur fossil principally in deep-sea deposits, and make their first appear-
ance in the Cambrian ; their period of greatest development falls in Jurassic
and Cretaceous time.

Sub-Order A. LYSSACINA. Zittel.

Skeletal elements either entirely detached, or only partial! // and in an irregular
fashion cemented together. Root-tuft often present.

ORDER iv SILICISPONGIAE— HEXACTINELLIDA 55

The Lif.^iriim are poorly adapted for preservation in the fossil state, since
the skeletal elements are but rarely cemented together to form a connected
framework, and the flesh-spicules are invariably destroyed. Notwithstanding,
complete sponges composed of large-si/ed, detached hexactins, have been found
in \ 'alaeozoic formations, and also in the Upper Jurassic of Streitberg ; and.
indeed, the oldest sponges that can lie determined with certainty all belong to
the Lyssacina.

Family 1. Protospongidae. Hinde.

l, >•///•, fitlit'-like, or spherical sponges, with walls composed of a single
In iti- r of cruciform f>'fr<i.dal spicules (stauractins), so arranged as to form quadrate
and subquadrate meshes. Elements non-fasciculate. The reticulation formed by the
larger fl>-nti'nt* /* divided into secondary squares by smaller spicules, so that the mesh-
work is constituted of several series of squares. Cambrian and Ordovician.

To this family belong the genera Protospongia, Salter, and PhormoseUa, Hinde.

Family 2. Dictyospongldae. Hall.

Usually large, funnel-shaped, cylindrical, or prismatic sponges, wlwse thin walls
are frequently diversified by ridges and prominences. Skeletal framework very regular,
and composed of larger and smaller quadrate meshes situated one within the other.
Framework farmed by bundles of slender spicules. Ordovician to Devonian.
Chiefly in Devonian of North America and Europe.

Dictijopliyton, Uphantaenia, Hall, and Hydnoceras, Conrad, occur usually in the
form of well-preserved moulds in Devonian sandstones and slate ; the silicious
spicules are totally destroyed.

Family 3. Plectospongidae. Rauff.

Thin-walled tubes with skeleton composed of a regular framework made up of an
ascending and approximately ring-like series of spicules; the latter form rectangular
to quadrate, but not very symmetrical meshes. Spicular rays fasciculate. Ordovician
and Silurian.

Cyathophycus, Walcott; Palaeosaccus, Acanthodictya, Hinde; Ordovician. Plec-
todenna, Hinde ; Silurian.

Genera incertae sedis.

Patter* i a i«, Miller (Strobilospongia, Beecher). In form of large botryoidal
clumps. Brachiospongia, Marsh. Vase-like sponges with broad inferior margin
prolonged into a number of hollow arms; Ordovician of North America.
These, together with Amphispongia, Salter, and Astroconia, Sollas, from the
Silurian of England, represent extinct families of the Lyssacina.

I'f/rituneina, M'Coy (Acestra, Koem.) Fascicles of long, stout spicules, sup-
posed to be root-tufts. Silurian.

llii<il».<ti'1i.«, Zitt. (Acanthospongia, Young). Skeletal elements relatively large,
in the form of regular hexactins and stellate bodies with reduced vertical ray,
and with inflated nodes. Root-tuft composed of elongated, slightly bent fibres,
sometimes terminating in four recurved rays. Cambrian to Lower Carbon-
iferous ; Great Britain.

Il'ilasterella, Carter, Spiradinella (Fig. 69), and Acanthactinella, Hinde, are
allied genera occurring in the Carboniferous Limestone of Great Britain.

56

COELENTERATA— SPONGIAE

CLASS I

Th»lM>rella, Hinde (Fig. 70), from the Carboniferous, has thin walls com-
posed of a layer of robust, irregularly amalgamated hexactins. As a rule, two
of the rays lying in the same plane divide dichotomously from the nodes
outward, so as to produce a six-armed instead of a four-armed cross. In
Jxtri-<ii-tiii<-!la, Hinde (Fig.
71), all of the rays lying
in the same plane divide
in two or more branches,
thus giving rise to many-
rayed, extremely diverse,
stellate, and corolla -like
bodies. Carboniferous ;
Ayrshire.

Astraeospongia, Roem.

(V\(T 7'^} TVnVk walWI 77/"/;«.^,v//« gruciHs,

6Cl' Hinde. Carboniferous

depressed, bowl - shaped, Limestone ; Dairy, Ayr-

. shire. Dermal layer wil.li

upper surface concave, fused stellate spimies,
lower convex, without B/i <»«** Hinde).

FIG. 70.

FIG. 69.

ll'rightii, Carter
sp. Carboniferous Limestone ;
Sliu'o, Ireland. A, Normal hex-
actin. B, Hexactin with forked
rays, 5/i (after Hinde).

FIG. 71.

Asteractinella expansa,
Hinde. Carboniferous Lime-
stone ; Dairy, Ayrshire.
Skeletal element, 5/i (after
Hinde).

FIG. 72

Astraeospongia meniscus, Bumb.
Silurian; Tennessee. A, Sponge, in
profile, -/3 natural size. IS, Upper
surface of same.

traces of attachment. Skeleton composed of relatively large, homogeneous,
uncemented cruciform spicules ; six of the rays are disposed in the same plane,
while the two rays projected at right angles to these are reduced to short,
button-like prominences. Common in Silurian of Tennessee and Devonian of
the Eifel.

According to Hinde, ThoUasterella and Asteractinella constitute a distinct
order (Heteractinettidae), while Astraeospongia is made the type of the order
Octaclinellidae. I should prefer, however, to regard these two groups as
aberrant Hexactinellids, in which supernumerary rays are produced by
branching.

Sub-Order B. DICTYONINA. Zittel.

Skeletal spicules cemented to fwm a continuous framework in such a way that
every arm of a hexactin is applied to the cm-responding arm of an adjacent spicule,
and both rays become enveloped in a common silicious covering. Hoot-tuft absent.

The Dictyonina 'are probably descendants of the Lyssacina (possibly from
Protospongia- arid Dictyophyton-like forms). They appear first in the Trias, and
play a prommen4r0/<2 as rock-builders in the Jurassic and Cretaceous. Their
lattice-like ske4e"ton$* are frequently replaced by calcite, or are dissolved away

ORDER IV

8ILICI8PONGIAE— HEXACTINELLIDA

and merely indicated l>y cavities. The nmiv important f«>— il form- are divided
into the following familic-.

Family 1. Craticularidae. llauli. /'>/•- //,/,/,. ]>. j... Zitt.-l M..H Srlmi/.-.
Cup-sliapril, i-f/linili-ii'iil, liriiH'-liiitif. ••)• jl<itt<,,«l >y/,//,^ v. ,Syi/V///.//- /-

aiirf'tii-i- irifliuiif ilinfinrf

outer skeletal lat/rr, <nnl
occasionally covered

iritli it i/fliniff trt'li of

cemented spicules.
Canals simple, UMly

1> mi unit iii<! in flu-

Jurassic.

//////•/'. //>// y//v,//-/7r'/ /'// '/ /A/'7.v/////-/ /,/' ///,

Upper Jurassic; Strt'itlicr^, Krancuiiia.
1- - :, natural sixc ; l>, Enlarged jiortiuii ol' ouli-r surlan- \vitlmut di-rmal

n minimi n

Tremadictyon,

Zitt. (Fig. 73). Cup-,
plate -shaped, or
cylindrical, with wide
cloaca. Canal-open-
ings on both sides
in alternating rows.
Base nodular; ex-
terior veiled over Fio 73
with delicate net- Tremadictyon reticuiat™,, Goi.if. sp." '

WOrk Of amalgamated ". *P<>i',-<'. - :, natural Size ; /., Knlar-.-d .

. . ,. layer: c, Portion with well-preserved dermal layer, :; i : </. Skeleton, '-' \.

hexactins, extending

even across canal pores. Skeletal framework with more or less

cubical meshes. Very
Upper Jurassic.

Craticularia, Zitt. (Fig. 74). Funnel
shaped, cylindrical, or flattened : simple,
or branching. Canal-openings on both
surfaces either round or elliptical, and
regularly distributed in vertical and
liori/ontal rows. Canals short, ending
blind. Jurassic, Cretaceous, and
Miocene.

Sporadopyle, Zitt. Cup- to funnel
shaped or conical, occasionally branch-
ing. Canal-openings on outer surface
irregularly distributed, <>r arranged in
quincunx; on cloacal surface in vertical
rows. Upper Jurassic.
Goldf. sp.
SpJienaulax, Zitt., Ferrucocoelio, Etall, etc. Jurassic.

I'riitiriilnriii

Muggendorf, Franconia.

Upper .1
natural

", Sponge, !/•
I, Latticed skeleton, 1% ; c, Thickened dernial layer.

Family 2. Ooscinoporidae. Zittel.

Calycoid, beaker-like, lobate, branching, or stellately concolntud *p<»t ;/>•<, //•//// flint
walls perforated on both side* by mimci-mi* <-<in'il-»in'tiiinj* <irr<i />>/<'>/ in »lf> -unit in;/

58

COELENTERATA— SPONGIAE

CLASS I

nnwls short, ending blind.

Framework compact, with fine meshes; dermal
layer replaced by thicken-
ing of outermost skeletal
layer. Spicular nodes solid,
more rarely perforate.
Cretaceous.

Leptophragma, Zitt.
Beaker-shaped, with root-
like attachment. Walls
thin, covered on both
sides with small canal-
openings arranged in
alternating rows. Mesh-
work very closely woven,
spicular nodes solid.
Middle and Upper Cre-
taceous.

Pleurostoma, Roem.,
Guettardia, Mich. Cre-
taceous.

Coscinopora, Goldf.

(Fig. 75). Beaker -like, with branching roots. Ostia small, round, and in

alternating rows. Skeletal elements in part with perforated intersection nodes.

Root consisting of long silicious fibres. Dermal layer formed by thickening

and fusion of outermost hexactins. Cretaceous.

Coscinopora infundibttliformis, Goldf. Upper
Westphalia. «, Complete individual, 1/2 natural
natural size ; c, Same, 3/i ; cl, Skeleton of cup, l^/j ;

Cretaceous ; Coesfeld,
size ; b, Outer surface,
e, Skeleton of root, 12/j.

Family 3. Staurodermidae. Zittel.

Top-shaped, funnel-shaped, or cylindrical, moi'e rarely branching or in clumps.
Ostia and postica irregularly distributed, or in alternating rows. Skeletal framework
more or less regular; intersection n 7

nodes thick or octahedrally excavated.
The outer, or both surfaces of the
wall provided with large, stellate
spicules (stauractins), which differ
from those of the rest of the skeleton,
and are either but loosely cemented
together, or are embedded in a con-
tinuous silicious skin. Jurassic and
Cretaceous.

FIG. 70.

Cypellia rugosa, Goldf. sp. Upper Jurassic; Stroll berg,
Franconia. a, Sponge, Va natural size; ft, c, Dermal layer, i-'/i-

Zitt. (Fig. 76). Top-
shaped, bowl-shaped, or branching,
without root. Canals irregu-
larly distributed, crooked, and
branched. Lattice skeleton with

irregular meshes, intersection
nodes perforated. Dermal layer composed of large, four-rayed stauractins
embedded in a thin, continuous, or perforated skin. Very common in Upper
Jurassic Spongitenkalk.

ORDER IV

SILICISP()X(JIAE-HEXACTINELLIDA

r,o

Zitt. Funnel-shaped or plate-like, with broad and shallow
cloaca, into which the large, round postica of short canals open. Inner and
..liter surfaces provided with dermal layer, in which stellate spicules are em-
bedded with reduced externally
and internally directed rays.
Upper Jurassic.

Casearia, Quenst. ( V I i 1 1
drical, with numerous annular
constrictions. Cloaca deep,
tubiform ; dermal layer re-
latively thick, and made up
of cemented stellate spicules.
Upper Jurassic. C. articulafu,
Goldf. sp.

Porospongia, $ Orb. (Fig. 77).
Compressed and expanded, Flo. 77.

more rarely bulbous or cylin-

Porospongia impressa, Golclf. sp.
imconia. a,
e, Skeleton, M/

Upper Jurassic; Muggendorf,

drical. Superior surface pitted Fra'*?™. A Fras»ient in natliral size = »• D'

with large exhalent apertures
of short, blindly terminating cloacae, and covered over with a dense or finely
perforate silicious skin, in which cruciform spicules and regular hexactins are
embedded. Lattice skeleton with cubical meshes ; intersection nodes imper-
forate. Upper Jurassic.

Family 4. Ventriculitidae. Toulmin Smith.

Wall intricately convoluted ; folds radially disposed, generally vertical in direc-
tion. Radial canals ending blind. Longitudinal furrows developed along folds of
the wall, and either open, or partially covered
over with dermal layer, which is usually
formed by thickening of the outer skeletal
layer. Skeletal framework, with octahedrally
perfoi'ated nodes. Roots consisting of elon-

Zltt. Up ,

•ma. ", Sponge, I/a natural size ; ?>, Skeleton, is/,.

Fcu*yteia*smaCarteri.Zltt. Upper Jurassic; Hohenpiilz,
I

Ventriculites striatvs, Smith. Quadratenkrciilc;
Linden, near Hanover, a, Sponge, i/., natural
size ; b, Transverse section, i/, ; c, .Ski-l.-fmi, U/j.

gated silicious fibres united by transverse bridges and ivithout axial canals. Jurassic
and Cretaceous.

Pachyteichisma, Zitt. (Fig. 78). Turbinate or bowl-shaped, with very thick,

60

COELENTERATA— SPOXGIAE

CLASS I

convoluted wall. Folds separated on outer surface by deeply incised furrows,
on inner surface by shallow furrows. Framework extremely regular. Root
and dermal layer absent. Upper Jurassic.

Venfriculites, Mant. (Fig. 79). Bowl-, plate-, beaker-, funnel-shaped, or
cylindrical, with wide cloaca. Wall thin, convoluted ; folds separated on both
sides by closely crowded longitudinal furrows. Lattice-work of skeleton more
or less regular ; outer layer thickened ; roots present. Common in Middle
and Upper Cretaceous.

Schizorhabdus, Rhiwpotcrion, Polyblastidium, Zitt. ; Sporadoscinia, Pomel ; Lepi-
dospongia, Roem., etc. Cretaceous.

Family 5. Coeloptychidae. Zittel.

Umbel- or mushroom-shaped, with stalk. Wall thin, deeply folded. Convolutions
radially arranged, becoming furcate toward periphery of umbel, and exposed on lower

FIG. SO.

Coe'optychium agaricoides, Goldf. Upper Cretaceous; Vordorf, near Braunschweig. .-', Top view. B, Pro-
file. C Under surface, 2/3 natural size. D, Skeleton, 61^

surface. Marginal and upper surface enveloped with porous dermal layer entirely
covering the folds. Ostia only on under side of umbel, situated on backs of the folds.
Framework very regular; intersection nodes octahedral, perforated; rays of hexactins
provided with slender, thorny processes.

Coeloptychium, Goldf. (Fig. 80), occurring in the Upper Cretaceous of
Northern Germany, England, and Southern Russia, is the solitary genue.

ORDER IV

SIL1CISPOXG1AK HEXACTINELLIDA

61

Family 6. Maeandrospongidae. Zittel.

msistinff of thin-walled, intricate!?/ /»/>.'/rinthme, and partially
amalgamate,/ tub,-* or filling which form tuberous, pyriform, beaker-shaped, or
like branching stocks- !•• „

tween the <«/»>• are cavities
mill interstices of consider-
able &izet irliicli coiisfiftitt
theso-ntllnl inti'ir.nnnlifii-
lar syxfi'iii. /-'"in' canals
faintly developed. Dermal
t, or represented
silicious

superji''/"/ >•/•///. Almn-
< la nt in the Cretaceous,
and also represented
l>v numerous recent

FIG. SI.

Plocost-jn ili in fii'iiuait, (ii-in. Greensand ((Vnonianian); Hanowitz, Hungary.
a, Fragment in natural size ; b, Dermal lay.-r, live times enlarged ; c, Sk-l.-tnn
of interior, 12/j ; ri, Outward portion of skeleton, 12/1.

genera.

Plocoscyphia, Reuss. (Fig. 81). Clump-like or bulbous stocks consisting of

labyrinthic, anastomosing tubes or foliae. Walls of tubes thin, perforated by

numerous small ostia. Latticed skeleton, intersection nodes solid or perforate.

Cretaceous.

Ji'-d-iflu, Schliiter (Fig. 82). The thin walls of the shallow, beaker-like

sponge are composed of vertical tubes having a radial disposition and fused with

one another along
the sides. Between
the tubes are large
interstices ; near the
base the tubes de-
velop hollow, spinous
processes. Lattice
skeleton very regu-
lar, exactly similar
to Codoptychium.
Upper Cretaceous ;
Westphalia.

Tremabolites,
Zitt. ; Etheridgia,
Tate ; Zittelispongia,
Sinzoff, etc. Upper

kelandi, Srlilut. C^iadrat.-nkrfide . ( 'u.-st'cld. AV.-st]»lialia.

Camerospongia,

d'Orb. (Fig. 83).

(Jlolmlar, sul (-globular, or pyriform. Upper half of the body enveloped by
.smooth silicious skin, and with large circular depression on the summit; lower
half marked by undulating ridges and furrows, and passing gradually into a
stem. Interior of sponge body consists of thin- walled, labyrinthous tubes.
Upper Cretaceous.

Cystispongia, Roem. (Fig. 84). Like the preceding, but with dense silicious

FIG. 82.

A, Sponge CretaceOUS.

l.n.lv. i ., natural six-- ; n, Ostia of radial canals ; /; Hollow, root-like processes of
wall. B, Sk.-l.-t.nii, 5J/J.

62 COBLES TERAT A— SPONGIAE CLASS i

skin punctured by large, irregularly shaped apertures, uniformly enveloping the

FIG. 83.

Camerospongia fungiformis,
Goldf. sp. Planer; Oppeln,
Silesia. Natural size.

FIG. 84.

Cystispongia bursa, Quenst. Cuvieri-Planer (Turonian) ; Salz-
gitter, Hanover, a, Sponge, natural size ; b, Dermal layer with
underlying skeletal framework ; c, Skeleton, 12/j.

whole sponge body. Body composed entirely of tubes. Cretaceous and still
living.

Sub-Class 4. CALCISPONGIAE. Calcareous Sponges.

Skeleton composed of calcareous spicules of three-rayed, foitr-mii<><1, or uniaxial t <//><•*.

The external form of the Calcisponges is quite as variable as that of the
silicious sponges, and reminds one particularly of the Lithistida. Like the
Lithistids, too, the thick-walled Leucones and Pharetrones have a canal-system
consisting of a central cavity into which radial excurrent
canals conduct ; while the numerous tributaries of. the latter
end in ciliated chambers which are fed by fine incurrent
canals. In the Sycones the wall is perforated by simple
radial tubes, but in the thin-walled Ascones it is pierced by
mere holes.

The calcareous skeletal elements lie free in the soft parts,
sometimes forming but a single layer disposed in the same
plane (Ascones) ; sometimes their disposition is more or less
distinctly radial, following the canal courses (Sycones) • some-
times they are irregularly crowded together (Leucones) ; and
sometimes they are closely apposed in the form of solid anastomosing fibres
(Pharetrones). Regular triaxial spicules are of the most common occurrence,
next monaxial spicules, sharpened on both sides, and more rarely four-rayed
spicules.

Owing to the ready solubility of the skeletal elements in calcareous sponges,
they are usually but poorly preserved in the fossil state, and are ill-adapted for
microscopical investigation. The three-rayed and rod-shaped spicules which are
united in fibres are seldom distinctly recognisable as such, since, as a rule, they
are either wholly or partially dissolved, and are converted into homogeneous or
crystalline fibres of calcite (Fig. 88) ; in these minute threads of calcite may be

•\( :>V-A^_;I ^

FIG. 8:

ORDER I CALCISPONGIAE— PII A II MT1K >.\ Ms

seen radiating in all diivrt ion> tn.m miim-roii- rent ivs «.t rry>talli.-at inn. SI.HH-
times such calcareous skeleton- afterwards Keeomr silicilicd. It i-
therefore, that the present eheniieal n>mpi»jt i«»n »\ a I'M— il -[lon^e fnrni.-li«- n~

Fibres of a PAorctroTM. composed

raynl f.iiiciiI.'S (r,-r»i<i<MI<i oyUndliOO,
sp. Upper Jurassic), *>/i.

Fi... 88.

--il <-al<"il<-<,ii-

spi.n^i- alt'-M-d liy crystalli.sa.
tiun, 4" ,.

no clue in regard to its original character, since during the process of fossilisatimi
a silicious skeleton may become converted into a calcareous, and u ealeare<>n>
into a silicious.

Of the four orders of calcareous sponges — Pharetrones, Si/cones, A scone*, and
Is-ii'-mics — only the first two are of practical importance to the palaeontologist,
traces of the others being either wanting or extremely fragmentary.

Order 1. PHARETRONES. Zittel.

Wall thick ; canal-system like that of the Lithistida, though sometimes indi*tii»1
and apparently absent. Spicules arranged in solid anastomosing fibres ; a smooth or
corrugated dermal layer frequently present. Devonian to Cretaceous; unknown in
Tertiary and Recent.

Eudea, Lamx. Cylindrical or club-shaped, usually simple, rarely branching.
narrow, tubiform, extending to the base, and terminating above in a

Fio. 89.

Peronidella

'. Must.

sp. Upprr •)"!•-
as>ic- ; Mu^gcii-
dorf. Reduced V-'-

Fio. 00.

Peronidella dumosa, From.
s|i. mis; Berklingen, Brattn-
schweig. Natural size.

Fin. HI.

\CorynellaQuenstedti, Zitt. Conil-Ha- : Natt-
li.'iin. o, Six>nge, natural size ; '•,
fibres, 4/i.

round osculum. Dermal layer smooth, perforated by ostia of short canals.
Triassic and Jurassic. E. clavata, Lamx.

Peronidella, Zitt. (antea Peronella, Zitt. non Gray, Sip/wiwcoelw, Pol,'

64

COELENTEEATA— SPONGIAE

CLASS I

From.), (Figs. 89, 90). Thick-walled, cylindrical, simple, or branching. Cloaca

tubiform, extending to the base ; base sometimes covered by dense dermal layer,

the rest of the exterior finely perforate. A distinct canal-system absent. The

coarse, anastomosing skeletal fibres composed of closely packed three-rayed and

one-rayed spicules. Sparse in Devonian (P. constricta, Sandb. sp.) ; common in

Trias, Jurassic, and Cretaceous.

Eii*il>]n>in-U<ii Zitt. (Fig. 92). Similar to preceding, but thin-walled, with

broad cloaca extending to the base, into which conduct radial canals arranged

in vertical rows. External surface perforate. Upper Jurassic.

Corynella, Zitt. (Fig. 91). Knob-like, cylindrical, or top-shaped, thick- walled,

simple, or composite. Cloaca funnel-shaped, shallow, terminating below in

a series of vertical
branching tubes ; ex-
halent aperture often
surrounded with radi-
ally diverging furrows.
Ostia conducting into
numerously branching
radial canals, which
unite again in larger
excurrent canals, and
open into the cloaca.
Common in Trias, Jur-
assic, and Cretaceous.
Usually composite stocks made up of hemi-

spherical, or short pear-shaped persons, with base enveloped by compact dermal

layer. Summit dome-shaped, with shallow cloaca surrounded by radial furrows ;

radial and vertical

canals terminating

along sides and basis

of cloaca. Skeleton

constituted of short,

blunt, and bent uni-

axial, and also of

three- and four-rayed

spicules. Triassic and

Jurassic.

Holcospongia, Hinde ;

Jurassic and Creta-

~ 7,

CCOUS. bestromOStella,

Zitt.

FIG. 92.

Rnxil>lionella Bronni,
Miinst. sp. Coral-Rag;
Nattheiin. Natural size.

. FIG. 93.

Oculospongiu,
tul)uli/era,Gol<lf.
sp. Kreidetuff ;
M a e s t r i c h t.
Natural size.

Stellispongia
Qnenst. sp. Coral
Nattheiin. Natural size.

Stellispongia, d'Orb. (Fig. 94).

FIG. 95.

l^ii'xirtostoma ucutiinargo, Roein.
Hils ; Berklingen, Braunschweig.
Upper surface, natural size.

lll«i/>hi<.1onema Farring<l<>u< •//.<( ,
.Sharps sp. Lower Cretaceous
(Aptiaii) ; Farringdon, Berkshire.
-/3 natural size.

Oculospongia (Fig. 93) and Diplostoma,

Trias to Creta-

ceous. Synopella, Zitt. ; Cretaceous.
From. ; Cretaceous.

Eiasmostoma^ From. (Fig. 95). Foliate-, ear-, or funnel-shaped. Upper (i.e.
inner) surface covered with smooth dermal layer, in which large shallow" oscula
are situated ; under surface cribriform. Cretaceous.

Rhaphidonema, Hinde (Fig. 96). Beaker-, funnel-, or twisted leaf -shaped.
Inner or upper surface smooth, with very small oscula or pores. Outer surface
rough, cribriform. Canal-system indistinct. Trias, Jurassic, Cretaceous.

Paehytylodia, Zitt. Funnel-shaped, thick-walled ; base with smooth dermal

ORDER II

CALCISPONGIAE— s Y< < »N KS

layer; oscula invent here. l»ut absent on other parts d
composed i.f very coarse, anastomosing til.r.-. < Jretaceous.

(loldf. -p.

exterior. sk.-i.-t..n
/'. ////'»//<//'/,/////',„•//„,,

Order 2. SYCONES. Haeckel.

//",///.< /,•">-,,•<,,/ l,if .<iin/'/''- •••tnnl.<
f'1 if.

reference to the

wUm

Mostly small, delicate forms inhabiting shallow water.

/'/•*»/".<//»•»//, Zitt., from the I'pper .Inra.-siY of Streitbrrg. is a small, eylin-
drii-al, or eonical form agreeing with living Sycons in the arrangement of its
radial canals.

To the Sycons, also, Rauff assigns the calcareous sponge ^ihim-tozoa described
by Steinmann (.lahrb. f. Mineralog. 1882, II. p. 139), which is distinguished
from all other Calcisponges by
having a most remarkable seg-
mentation, such as occurs in the
Lithistid genus i'n*'itriti.

The oldest Sycons are Sollasia,
jjtfliblysiphonellct, and Sebargasia,
Steinm., from the Carboniferous
Limestone of Asturias. In the
Triassic of St. ('assian and See-
landalp, near Schluderbach in
Tyrol, are found Colospongia,
Thaumastocoelia, and Cryp-

';,, <t ,.;,,, Tlmltnm nnrit ]:"' •'•"'•-•'" " »«>t«iH" "*, Mant. sp. Aptian ; Farrin-don, Berk-

M, Steinmann. l/iaUtmopOia, 8li.re> A^ 15l,sh-lik(- colony, one person sliced open; natural
Roem., and Barroisia, Steinm., size. ^ Mvido^cut l^ro^otMquely, «^, o, Janction Of

i -»r- i n two se-inents; '., Cloaca; o, Osculuni ; (/. Hadial canals. < . I'.
occur 111 the Lower and Middle Three-rayed skeletal spi.-ul.-s. •"•• l and r-'(1 (after Steiniuann).

Cretaceous.

l',<tm>i*i<i (FentricutiUs, Zitt. non Defr., SpJuurocoelia, Steinm.), (Fig. 97).
Occurs sometimes as simple, cylindrical, or clavate individuals, and again in
the form of bushy stocks. Outer surface frequently constricted, summit
arched, with osculum in the centre, cloaca tubitorm. The cylindrical indi-
viduals are composed of thin-walled, hemispherical, or compressed segments,
which are so arranged that the roof of one segment serves also as the floor of
the next following. The wall is everywhere perforated by simple radial canals,
and is made up of fibres composed of three-rayed spicules. B. helvetica, Lor.
sp. Aptian : La I're>ta, Swit/erland.

Range and Distribution of Fossil Sponges.

The phylogeny of the J///."/syo/,r/iae, Ccratospongiae, and a part of the

', owing to their perishable organisation, must ever remain involved in
doubt. Nevertheless, isolated spicules prove the existence of Monactinellids
and Tetractinellids in Palaeozoic seas ; while in the Trias, Jurassic, and Cre-
taceous these forms become important rock-builders, and certainly play an
active part in the formation of hornstone, chalcedony, and flint. In the Ter-
tiary, spicules referable to existing genera are quite common.

VOL. i F

66 COELENTERATA— SPONGIAE CLASS i

The former distribution of the three best preserved sponge groups — the
Lithistids, Hexactinellids, and Calcisponges — is noteworthy. The living repre-
sentatives of the first two orders inhabit deep, or moderately deep water, while
the calcareous sponges predominate in shallow waters bordering the coast. And
hence, since fossil Calcisponges likewise occur almost entirely in marly, clayey,
or sandy strata of undoubted littoral origin, and are absent in limestones
where Lithistids and Hexactinellids predominate, it is plain that the distribu-
bution of both fossil and recent sponges has been occasioned by like physical
conditions.

In the Cambrian occur the Lithistid genera Archaeosci/phia and Nipterella, and
in the Ordovician and Silurian of Europe and North America are found a number
of Teiracladina (Aulocopium) and Eutaxidadina forms (Astylospongia, Palaeomanon,
Hindia), together with a few Rhizomoiina. In the Carboniferous Ehizomorina
and Megamorina are sparsely represented; but in the Upper Jurassic, and
especially in the Spongitenkalk of Franconia, Swabia, Switzerland, and the
Krakau district, the Lithistids exhibit an astonishing development, and
occasionally form thick beds. They occur only sparingly in the Lower
Cretaceous, but are abundant in the Planer, Greensand, and Upper Cre-
taceous of Northern Germany, Bohemia, Poland, Galicia, Southern Russia,
England, and France. The Tertiary being nearly everywhere made up
of shallow - water formations, the absence of Lithistids and Hexactinellids
is not surprising. They persist locally, however, as, for instance, in the
Upper Miocene of Bologna, and in the Province of Gran in Northern
Africa.

The range of the Hexadinellida is in every respect similar to that of the
Lithistida. Beginning in the Upper Cambrian, they are represented in the
Ordovician and Silurian by peculiarly modified Lyssacina forms (Protospongia,
Phormosella, Cyathophycus, Palaeosaccus, Pledoderma, Pattersonia, Brachiospongia,
Didyophyton, Astmeospongia). The same group continues also through the
Devonian, where Didyophyton and its associates are conspicuous for their wide-
spread distribution in North America. A few aberrant Li/tsarina, which Hinde
designates as Heteradinellidae, are found in the Carboniferous. During the
Mesozoic and Cenozoic eras the distribution of the HexartinrUidn is nearly
identical with that of the Lithistida ; although here and there beds occur
which are charged principally with Hexactinellids, and others chiefly with
Lithistids.

Very different conditions are presented by the Calcisponges, among which
only the Pharetrones and Sycons are of geological importance. The oldest
calcareous sponges occur very sparsely indeed in the Middle Devonian and
Carboniferous Limestone. They appear in considerable diversity in the Alpine
Trias (St. Cassian and Seelandalp), but outside the Alps are almost wholly
absent. In the Jurassic they occur in marly beds of the Dogger (Ranville,
Swabia), and also in certain facies of the Malm (Terrain a Chailles, Coral-Rag of
Nattheim, Sontheim, etc.) in Southern Germany and Switzerland.

The Lower Cretaceous (particularly the Neocomian of Braunschweig, the
Swiss Jura, and the Paris Basin), as well as the Aptian of La Presta, near
Neuchatel, and Farringdon, Berkshire ; and also the Middle Cretaceous (Ceno-
manian) of Essen, Le Mans, and Havre, are characterised by an abundance of
well-preserved Pharetrones, and a lesser number of Sphinctozooid Sycons. In
the Tertiary, however, both groups are wanting, although the existence of

BUB-BRANCHI] > CNIDARIA— ANTHOZOA

~j - ,.

calcareous spoilers is still illdicat e< 1 1 >y oeea-i< >M;I | del.iehed lri;ictiii-. \Vitll tile
clost- of tllr Cretaceous, tin- IMiaivtroiies si-i-ill entirely tu ha\e disappeared. '

SuB-Bi;.\.\< H II. Cnidaria.

The I'niiliiri'i or \< //////ii/*//»i/-i/ have a radially symmetrical body. and a
terminal niout h-openin^ surrounded by Heshy tentacle-. In tin- ectoderm
(.-ometimes also in the entoderm) midoblaM - an- common. from tin- content>
of which t lu-r.-nl cells (//>/,/, //V//.s/.<), filled with an nrticatin.u fluid and contaiiiiii-
a liolli)\v, spirally coiled thread, arc developed. Kach cnidohlast pOMC

fine superficial process (en i</<»'/l), which is very sensitive to mechanical stimuli.
The mesoderm is sometimes entirely absent, but the ectoderm and eiitoderm are
>i lonely developed. The ectoderm or mesoderm frequently secrete.- a calcareous
or horny skeleton, and both ectoderm and entoderm are eoncerned in the pm-
<1 net ion of muscles and nerves. The sexual organs are the product of th'
entoderm.

The Cnidaria are divided into two classes: Autlm-jm and ////'//

Class 1. ANTHOZOA = ACTINOZOA. Coral Polypi

I'.«imllt/ sessile, cylindrical polyps, possessing a mmith >•///•/••/// ////r-/ /"/ ttnl
oesophagus, and gastrovascul<n- i-m-lft/. The latter is diri<l«l In nun, • ma*
/>"rf it inns (mesenteric folds) into a system of radially dispo&'tl JUHK-IK-*. A cakareotu
or }t»rn >/ tib-lrfon is frequently developed.

The simple polyp individuals have the form of a cylindrical or conical tithe.
at the distal end of which is situated a muscular disk perforate! centrally by
the -lit-like or oval fissure of the mouth. The mouth is furnished with a ring
of tentacles round its margin, and opens into a membranous oesophageal tube

1 To the sponges, and iu fact to the Hexactinellids, Hinde lius ivt.-irt-.l the >ingular group

•iiliilne occurring iu the Ordovician, Silurian, and Devonian Systems. Tin--,- an- all free,

-lolmlar, cup-, or platter-shaped bodies containing a central cavity, and who>e i-alraiv-m.- wall is

i-i.iupi'.sed nt elements arranged in (jiiinciinxial order. The elements lying on the outer or under

side of the wall consist of small rhomlioidal plate- having tour transverse rays dispo-i-<l cr.

and one inwardly directed vertical ra\. '1'he systeinatii- po-iti'Ui of thes,- prol.l.-matical fc-iK

I ,.f, ,/„,/,•,•!<>, /. Pasceolu*, /*<•/,,,,/;/,*. /'<,///;/,, /,<,*/>//< i,', •,'/,•*) is wholly ,-onje.-tnral ;

(iiimbel as-, igns them to the calcareous algae (Doctfloporidcte), and others to the Foraniinifi-ia <•!

h monograph l.y A'"/'.//' in AMiamlliingen k. bayer. Akad.-mi,-. II. ('].. Hd. XN'II.. l^l'l'.

Milne -Edioardf, //., .-t Haimt, ./.. Hist. .ire Naturelle <les Corallaires : :5 vols. an.:

I'aris. 1857-60,
;/ Edvnrdt, //.. ft //.'//».-, ./.. M.mo^K-iphie des I'olypi. -r- l..>^ih- drs 1,-ii-ain- ].al.-.,/,,i(|ii.-s.

Aivh. du .Museum. Pari-. \'M]. \'.. l^.M.

.l/////« -AW/'vov/s. //.. ,-t //,/>',!»'. ./., Monograph of the British fossil Coral-. Pala. tl
lhnn-,1,1, M.. ibid. ISti'i-tJ'.t. and 1S7'J.- -Me'/ision of the Families and lieiiera of the Srlemdermic

Zoantharia or Madreporuia. .lourn. Limn-an Sor.. Londmi. Xnni.^y. \-..l. \\"lll.. ls^i.
/•',-,1/iii-itfi'l, E. <li'. Introduction a I'l'-lude des IVypiers fos.-iles. I'ari-. 1S58-61.
l-'i-«iii>'iiti-i, K. ill-, Zoo])hytes. EW^ontologie iVa., raise. Since 1861.
A""/"/, /•'., Monographic des Polypiers Jura-si. pie.- dr la Sui-se. Abhandl. Sehwei/. pahie..:

1880-94, vols. VI |. -XX 1 1.
K'n'Ii, <'h. ran. Die iinijeschlerhtlirhe N'rrmeliruim dt-r jialai-o/oj-rhen Knrallrn. PalaeontOgraphica,

Kd. XXIX.. 1883.

Prat* K., Ueber Septalstructnr. Palaeontographica, 1882. XXIX.
Quensttdt, /•'. .1.. IVtrela.-tenkun.le DiMits.-hlau.ls. Hand VII., 1889. Rohrcn uinl Sternk..rallen.

ReU8*, -I. K., Sit/.UllLCsl.rrirhte drl Wirner Akadelnie. 1859, 1864, 1865, 1870 I Dellksrhrif

VII., XXIII., XXVIIL, XXIX., XXXI.. XXXIII.

68

COELEXTERATA— CNIDARIA

SUB-BRANCH II

conducting into the gastric cavity. The outer covering of the body, whose
parts are designated as wall, oral disk, and pedal disk, are constituted of
ectoderm and cntoderm, between which is a thin layer of mesoderm (Mesogloea).
Six eiatere»jnore radially disposed vertical partjt/ions (wseT^mesX-lTigs. 98, 99),

_

projecting inwardly from the body-wall, divide the gastric cavity into a serie's
of radiating compartments (mesenteric pouches}. The mesenteries are prolonged
upwardly as the hollow, muscular tentacles; while the generative organs are
attached to their faces near the lower end of the body. The mesenteries are
mvrivd on both sides with muscular tissues, and bear mesenteric filaments on
their curled inner edges. On one side of the mesenteries the muscle fibres are
transversely directed, on the other longitudinally. The longitudinal system
is usually considerably folded and thickened ; and the disposition of these
muscular portions (Miiskelfahife) is of great importance from a systematic stand-

point, since it reveals
the bilateral symmetry.
of many Anthozoans,
and enables one readily
to identify the anti-
meres. If a polyp in-
dividual be cut in two
by a plane passing
through the longer axis
of the mouth -opening,
then, in the Octocor«ll<i
(Fig. 98), the mesen-

teries of the right half
WJH have a]} the milS-

FIG. OS.

Diagrammatic section of
the soft parts of an Octo-

i-nriil/ii (Ali'ifnii in Hi), x, Oeso-
phagus ; 1, 2, 3, 4, Mesen-
teries of the left side (after
R. Hertwig).

Diagrammatic section of the soft parts of
a Hexacomlla. In the upper half (above the

line a— 5) the section passes through oeso
phagus s ; in lower half, beneath 1 "
Corallum indicated by heavy lines.

beneath the same. Clllar thickenings dis-
ivy lines, r, direc- -i ,1 . •> , -i -i

tive mesenteries. posed On the Hght-hai id

side, and those of the

left on the left-hand side. In the Hexacomlla (Fig. 99) the mesenteries are
grouped in pairs, with the muscular thickenings of any pair facing each other.
T\v«» pairs, however (those corresponding with the opposite extremities of the
longitudinal mouth), form often an exception to this rule, since these have the
muscular thickenings placed on opposite sides. These are called the directive
mesenteries, and serve to indicate the longitudinal axis of the body.

Only a few Anthozoa have permanently soft bodies ; the majority secreting
calcareous, horny, or partly horny and partly calcareous structures, termed the
skeleton or corallum. The simplest form of corallum is that composed of
microscopic, round, cylindrical, acerate, or tuberculated spicules of carbonate of
lime, which are developed in great quantities in the mesoderm and remain
detached in the soft parts (many Alcymaria). In a number of forms (Cornllhoti,
Mopseii, TiibijHU'a) the spicules are firmly cemented together by means of a
calcareous or horny connective substance, in such a manner as to form tubes
( Tubipora), or, when the secretion takes place chiefly at the base, a sclerobase,
or axis. Surrounding the axis is the soft coenosarc in which the polyps of the
colony are embedded (Fig. WQ1). In some cases the sclerobase is composed
entirely of horny matter without admixture of calcareous secretions. In the
so-called "stone corals" (Fig. 101) a consistent calcareous skeleton is formed
by the outer surface of the ectoderm. At the base of the polyp between each

OLA881 ANTHOZOA

l>;iii- of mesenteries, the infold. -.1 ectoderm secrete* siu;ill, round, oval, or irregular
calcareous bodies (ackrtfea); these arejojjjysed against one another in radial
direction-, and as oth. •• cessTvely hid down on the top of them, upright

partitions in- sep^d^Sternleisten, downs) are built up! Gradually, also, as the
p..lvp approaches maturity, the ba-al plate becomes ral«-ilied. owing to the
georetion l.y the outer surface of the ectoderm of numerous minute, cWly
crowded, calcareous bodies. The septa, however, grow considerably above the
Itase. and become lodged in the vertical interspaces between the mesenteries.
In the same manner, within the soft body- wall, a calcareous secretion may
take place, bind in- the outer edges of the septa together, and known as the
n',ill or tli.rn (M'U/n; H'miil. ntiiniillr). Both septa and theca are composed of
minute, denselv crowded calcareous bodies, in which delicate calcareous fibres
may be seen radiating in all directions from a central dark space. And since

- -

i:i,r<iir,mn ruiirmn, j^uin. (after Lacaze-Dnthiere).

Mrancli of red coral of roimm'rrc laid K\»-U alon^
1 IP- axis, and showing tlifi'i' jtulyjis in sci-tion IMII-
lit-ddi'd in rtt-shy cijfiiosark.

FIG. 101.

Astroiil'1* I'liii/ciiinri*. l.amx. sp. Mediterranean
(after Lacaze - Duthiers). Enlar-fd longitudinal
section of polyp with calcareous skrMon. te, T'-i;-
tacles ; oe, Oesophagus ; »i«>, Mesentery ; loc, M>— •
tt-rial pouches ; coe, Coenosark ; .^>t, s.-ptum :
col, Cohuiiella.

all the calcareous bodies forming the septa have a radial disposition, the
calcification-centres as seen in transverse sections form a dark, mostly inter-
rupted, and occasionally jagged median line, from which bundles of minute
fibres radiate outward in all directions. Similar calcification-centres are found
also in the theca. Sometimes the median dark line is uninterrupted and
di\ ides the septum into two separate lamellae.

The interstices between the sclerites forming the septa are either completely
filled with carbonate of lime (Aporosa), or there remain larger or smaller porous
-paces (J'l'i-furnta); in many cases, in fact, the septa are represented by a loose
network of sclerites piled up vertically, or merely by vertically directed spine-.

The number of mesenteries and septa within the visceral chamber is equal
to that of the tentacles, and is somewhat uniform throughout the different
sub-classes, orders, genera, and species. Increase takes place, as a rule, in such
a manner that whenever, as the polyp grows, a new visceral chamber is formed.

70

COELENTEEATA— CXIDARIA

SUB-BRANCH II

a new septum is secreted. The number, width, thickness, and mode of forma-
tion of the septa furnish important systematic characters, usually four, six,
eight, or twelve principal or primary septa are first formed, between which
septa of the second, third, and fourth cycles and so on are successively inter-
calated. The upper edges of the septa are sometimes smooth, sometimes
serrated or uranulated ; and they extend from the central depression to the
walls of the theca, either obliquely or in a curved line. This open, central
depression, formed by the superior edges of the septa, is known as the calice
(AV'7/, cul '//.'•)•

The sides of the septa are rarely smooth, but are commonly granulated or
furnished with rows of small prominences ; occasionally they are provided with
well-marked vertical cross-bars (carinae). When the projections on the sides of
the septa are in the form of conical or cylindrical transverse bars, they are termed

synapticula. Frequently the synapticula of
two adjacent septa become joined together ;
sometimes whole rows of them are fused,
together to form perpendicular bars, thus
greatly strengthening the septal framework.
In some corals (Athecalia) the development
of synapticula is such as to render an oute*
wall superfluous. With the upward growtjji
of the polyp, the theca gradually becomes
elevated, and its lower portions, as their
occupation by the soft parts ceases, are'
partitioned off by numerous horizontal or
oblique calcareous plates which bridge over
the interseptal spaces. These structures are
known as dissepiments (Traversen) and tabulae
(Baden); the tabulae are often nothing but
highly developed dissepiments, being dis-
tinguished from the latter merely by the fact
sol. coraiium split open that they extend across between the s&pta at

longitudinally ; true colu- •?

meiia in the centre, sur- the same level ; sometimes they are perfectly
ofpali- horizontal, sometimes they are arched or
funnel-shaped (Fig. 102), and sometimes incomplete. Dissepiments and tabulae
are most strongly developed in cylindrical forms, and frequently fill the in-
cluded space within the theca with a vesicular or cellular tissue.

When a number or when all of the septa are produced as far as the centre
of the calice, their free edges may become twisted so as to form an axial
structure, known as a pseudo-columella. Sometimes, however, a true columella
(Saulchen, Axe) is present ; this may be either a compact, styliform, or foliaceous
structure, or may be composed of a bundle of styliform or twisted rods (Fig.
10:>), or of thin lamellae. It extends from the floor of the visceral chamber to
the bottom of the calice, into which it projects for a greater or less distance.
The structures known as pali (Pfahlchen, paluli) are narrow vertical plates
which are inserted between the columella and the inner ends of the septa in
one or more cycles (Fig. 103).

The outer wall or theca is often formed by the secretion of a particular
ring-like fold of the ectoderm, and is constituted of distinct sclerites, having
separate calcification -centres, and connecting the outer edges of the septa

FIG. 102.

Lithostrotion
Murtin.i, E. and
H. -Longi-
tudinal sec-
tion showing
tabulae.

FIG. 103.

cyathus,

CLASS 1 ANTHOZOA 71

(Knflii'';ili,i). In many <•;,>«•> the peripheral edges of the septa become thickni.-d
and laterally fu.-ed tn form a spurious theca (Psetnl<>l/i' <•«/>" ); and occasionally
the dissepiments lyin-- in a certain zone become united BO as to form an inner
wall within the true thcca. The rj,tth<;;i is a usually smooth, sometimes
corrugated, superficial calcareous investment, which, according to Koch, is
merely a prolongation of the liasd plate, and is secreted by the outer surface
of the ectoderm, which is reflected over the top of the corallum. The epitheca
is deposited either directly upon the theca, or, when the septa are produced
outwards so as to form exothecal lamellae or ribs (W^-), the theca and epitheca
are separated. Exothecal lamellae, not corresponding in position to the septa,
are called y/>r//,///(v,s/W or rut/tic.

Sexual reproduction is comparatively rare among Anthozoans. Following
fertilisation and segmentation of the ova, ciliated larvae are born, which swim
a 1 >out for a time, become fixed, and develop into simple polyp individuals.
Asexual reproduction by gemmation or fission is much more common. The
individuals produced in this way remain connected with one another and with
the parent animal, forming polyp stocks or colonies of exceedingly various
forms and sizes.

New corallites are produced either within or without the calice of the
parent polvp. In extra- calicinal gemmation, the buds are thrown out either from
the sides of the polyp (lateral ija iunation\ or are formed in the common
calcareous matrix which unites the various corallites of a colony (coerienchymal
and f<>4«l ffemniatiori). In both cases the new corallites may diverge from one
another, being attached to the parent corallum only at the base, or they may
grow up closely opposed to the latter and to one another, so that the thecae
are in contact on all sides. In this way, branched, dendroid, or massive and
knob-like ( " astraeif orm ") compound coralla are formed. A less common
mode of increase is by basal or stolonal gemmation. In this process the Avail of
the original polyp sends out creeping prolongations (stolons) or basal expansions,
out of which new corallites arise. In calidnal gemmation buds are produced
within the calice of the parent corallite, according to one or the other of the
following methods : — Either certain particular septa become enlarged and pro-
duced so as finally to enclose a new calicinal disk (septal gemmation) ; or tabulae
are produced upwards in the form of pockets, from which neAv corallites are
developed (tiilnilur ijciniiuiti»n). In both septal and tabular gemmation, a portion
of the parent corallite including a part of the original Avail is concerned in the
formation of buds; while the septa or modified tabulae are converted into
portions of the new thecae, from which neAv septa then begin to grow inwards
toward the centre.

A peculiar kind of calicinal gemmation is that known as rejuvenescence. In
this method only one bud is formed within the parent calice, but it enlarges
until it completely fills the latter. By the indefinite repetition of this process, a
corallum is formed, consisting of a succession of cups placed one within the other,
of which only the youngest and uppermost is occupied by the living animal.

The beginning of reproduction by fission is marked by an elongation or
distortion of the parent calice, accompanied by the contraction of the Avail at
•pposite points along the margin. The constriction may proceed until it
divides the oral disk into tAvo halves ; or tAvo opposite septa may unite to form
a new theca. By this method, branching, massive, or astraeiform colonies are
produced, Avhich do not differ essentially from those formed by budding.

l-l COELENTERATA— CNIDARIA SIB-BRA:STH n

Frequently, however, individuals formed by fission become only imperfectly
separated, remaining proximally more or less closely in contact. In such cases
tin- mlices form continuous, straight, curved, or labyrinthic furrows, with more
or less clearly distinguishable centres.

The compound corallum of a polyp stock remains practically the same as in
solitary individuals, excepting that the conditions are more complicated when
the separation of the individuals is incomplete. Dendroid and astraeiform
• colonies frequently develop a common connective matrix or tissue (coenenchyma)
which unites the various corallites into a whole ; it is secreted externally to the
theca by an inverted external part of the polyp over the top of the corallum
(Jin mljiliiffe), and is sometimes dense in structure (Oculinulae), or it may consist
of a vesicular or tubular tissue. The separate corallites are often also united
by means of the septa, which are produced over and beyond the thecae, and
fused with those of neighbouring individuals. In such cases the interseptal
loculi are almost always filled with strongly developed dissepiments. All
structures developed in the included space within the theca, with the exception
of the septa, are designated collectively as endotheca ; those lying without the
theca as exotheca.

The Anthozoa are exclusively marine forms, and predominate in shallow
water. Many of the Actiniaria, Antipatharia, and Madreporaria occur also at
greater depths, ranging from 50-300, and sometimes even to 1500 fathoms. The
so-called reef-corals inhabit depths not exceeding 30-35 metres, and require a
temperature of the water of about 18° to 20° C. Hence, existing coral-reefs
are restricted to a zone extending about 30° on either side of the equator ;
they are distinguished according to form as fringing reefs, barrier reefs, and
atolls. While the stony corals (Forties, Madrepora, Turbinaria, Pocittupnw,
numerous Astraeidae and Fungidae) and the Alcyonarians (Hdiopora) are the most
important, they are not the only agents concerned in the formation of reefs,
as an active part is also played by the Hydromedtwc (Milleporidae), calcareous
algae (Litliothamnium, Melobesia), mollusks, echinoderms, bryozoans, and worms.
Of the ancient coral-reefs which have been formed in nearly all of the great
geological periods, those of the Cenozoic and Mesozoic periods are composed in
part of genera similar to those now living; while those of the Palaeozoic
represent genera and families that are now principally extinct, and whose
relation to living forms is often quite uncertain.

The Anthozoa are divided by Haeckel into three sub-classes — Tef
i, and Octoeoralla.

Sub-Class 1. TETRACORALLA. Haeckel.1

(Zoantharia Rugosa, Milne-Edwards ; Pterocorallia, Freeh.)
Extinct, palaeozoic, simple, or composite sderodermic corals, with septa, arranged
according to a tetrameral system, and either bilaterally or radially si/mmetrirnl ;

1 Literature (cf. also p. 67) :
Kunth, A., Beitrage zm Kemitniss fossiler Korallen. Zeitschrift der deiitschen geoloeisclien Gesell-

schaft, Hd. XXI.. isw. ;,.,.! XXII., 1870.
Dybotosl-i. It'. .V.. Monographic -<ler Zoautlmria Rugosa, etc. Archiv fur Naturkunde Liv-, Est-, un.l

Kurlands. lid. V., 1874.

/:>'/'i/it;>; F., Lethaea Palaeozoica, 1883, pp. 324-416.
>V///;//,>,-. (i,-m., Anthozoen dt-s rliciuischeii Mittel-Devons. Aldiaiulhmgeii der preussischen <*eolo-

gfechen Lmides-Austiilt, lid. VII I.. 1889.

81 B-OLA88 I

AKTHOZOA— TETRACORALLA

/// /
or dissepiments, mxi //•//// well^nctrbed^ fi/>fn>-nf/i/ /'•/•////•/'</ >/w/.

The Tetnn-iii-iiltii are especially characteri>ed by the possession <>f foui
principal or primary septa, between which four set- of new >epta ;uc subse-
quently developed. The four principal septa are sometimes of c<|ii;il pi-opor
tions. when they may bo either stouter ami longer than the others (>'/»/»/
thinner and shorter (Omphyma) } or they may In- of une,|u;d proportions. Of
the two principal septa which lie in the longitudinal axis of tin- corallum. nin-
(called tlie 1-iin/itnil tH-jifinii) is fre(juently situated in a depre — ion or furrow
known as tin- t'<*.<nli (Fig. 104); while the other or <•>//////,/• .«///////, is either
normally developed, or is more or less reduced. Occasionally the counter
septum is placed in a fossula, while the cardinal septum is normally developed .
but the two laterally disposed or nlur >>y/" are always e«|iial in sixe. The
remaining septa not infrequently exhibit a well-marked radial arrangement, in
which the longer and more strongly
developed usually alternate with the
shorter and less strongly developed.
New septa, according to Kunth and
Dybowski, are inserted in the follow-
ing order. First, a new septum is
given off on either side of the cardinal
septum (Fig. 104, A), and takes up a
position parallel with the alar septum.
This leaves an intermediate space
between the cardinal and the newly
formed septa, which becomes filled,
however, by the repeated insertion of
new septa one above the other in the
same manner as the first ; and hence
they diverge from the cardinal septum,
as they grow upward, in a pinnate
fashion. Likewise the two counter °0™te1' s''1)tnl
quadrants lying between the alar and
counter septa become occupied by lamellae which are given off from the alar
septa, and gradually arrange themselves parallel with the counter septum.
The mode of growth in the Tetrawratla will be readily understood on inspecting
the surface of such specimens whose septa are visible on the exterior, or whose
wall is readily removed by corrosion or polishing. One may then note three
distinct lines extending from the calicinal margin to the base ; these mark the
cirdinal and the two alar septa, from which the other pinnately branching
septa are directed obliquely upward (Fig. 105). The order in which the septa
are given off in the four quadrants is indicated by the numerals in Fig. 104.

Many of the Tetrwnrnllii multiply by sexual reproduction, and occur only
as single individuals ; asexual reproduction takes place usually by calicinal,
more rarely by lateral gemmation, and results in dendroid or massive colonies.

Dissepiments are generally abundantly developed between the septa,
which latter are compact, and the upper edges of which are either smooth or
serrated. Sometimes the dissepiments fill the whole interior with a vesicular
tissue, and the central visceral cavity is frequently entirely partitioned off by
horizontal, inclined, or funnel-shaped tabulae. The wall is usually composed

MI nnjili iiUu in 1i IIH'I inn r-
!/: nut ii in, K. aii'l II. ' u-
honilVrous Limestoiif ;
Tom nay, Bi-l^iuin. -/].
A. Cun'linal si-plum ; ij,
s, Alar

I 'I... 105.

Zaphrentif
Bill. Onlovician :
cinnati, Ohio. Natural
size.

COELEXTERATA— CXIDARIA

SUB-BRANCH II

of the thickened and fused septal edges ; sometimes it is invested with epitheca
and furnished with vertical rugae or root-like processes. A true coenenchyma
is absent. In a few genera the calice is provided with a lid or operculum,
which may be composed of one (Calceola) or of several plates (Goniophyllum).

With the exception of a few genera whose systematic position is uncertain,
all the typical TetracoraUa are confined to the Palaeozoic rocks. They are
probably the ancestors of the imperf orate Hexacoralla.

Family 1. Cyathaxonidae. Milne-Edwards and Haime.

Turlinatc or horn-shaped coralla, occurring only simple. Septa with regt/In,-

radial arrangement. Tabulae and dis-
sepiments absent.

Cyathaxonia, Mich. (Fig. 106).
Acutely pointed, conical. Cardinal
septum in fossula. Septa numerous,
extending inward as far as the
strongly developed styliform and
considerably elevated columella.
Carboniferous Limestone ; Belgium
and England.

Duncanella, Xich. Corallum top-
shaped. Septa nearly all of uniform
length and size, forming a spurious
columella in centre of the deep calice,
exsert at the base. Silurian ; North
America. D. lorenlis, Xrch.

Petraia, Miinst, (Fig. 107). Tur-
binate or conical. Septa short,
reaching to the centre only at the
Columella absent. Ordovician to Carboniferous.

FIG. 106.

Cyathaxonia

cnrnii, Mir.h.
( 'a rlion ifVrnr.s
Limestone;
Toumuy. Cor-
allum" with
fractured theca,
showing open
interseptal
loculi. 2/1-

Petraia
Must. Devonian;
Enkeberg, near
Brilon. Vl- a, Cor-
allum viewed from
the apex ; 6, Trans-
verse section below
the middle.

FIG. 10S.

PolycoeJw pro-
funda, Germ,
sp. Zechstein ;
Gera. l/i (after
Roemer).

base of the very deep calice.

Polycoelia, King. (Fig. 108). Horn-shaped.
Calice very deep; four principal septa reach
nearly to its centre, between which in each
quadrant are five shorter septa. Zechstein.

Kanophyllum, Dyb. Ordovician and Silurian.

Family 2. Palaeocyclidae. Dybowski.

Coralla simple, discoidal, or bowl-shaped. Septa
numerous, stout, approaching radial symmetry in
disposition. - Tabulae and dissepiments wanting.

r«l<ieocijdus, E. and H. (Fig. 109). Discoidal
to depressed top-shaped, with epitheca. Septa
numerous, radially disposed, the larger ones
reaching to the centre. Silurian.

Oombophyllum, Baryphyllum, E. and H.
Devonian.

Hadrophyllum, E. and H. Cushion-shaped, with epitheca.
septal fossula, that of the cardinal septum being the largest,
and North America.

FIG. 109.

»i>,Lin. Silurian;
Gottland. ". Tnp
view of calice;
b, Profile. 1/1.

FIG. 110.

M ic rocyct " >•
discus, Meek and
Worth. Hamil-
ton (Devonian);
North America.
J/i. ", (.'i>rallum
from below;
I, from above
(after Nicholson).

Calice with three
Devonian ; Eifel

srp.-t'l.Ass [

A NTHOZOA— TETRACORALLA

Meek and Worth. (Fig. 110). Like the preceding, but with
mly one septal fossula. Devonian ; North America.

Family 3. Zaphrentidae. Milne-Kdwards and Haime.

Cwalla ximjili; fiirliimif'; conical, <><• o//;,/,//v<W ; .^v/" numerous, exldliiui-i
in <trr<ni<i< an nt. Thirii iji-Hi'i-nllii formed by fusion of
eveloped ; ili**-i>impnts not very abundant in inter-

sry;//// Ix'uli.

N/,-,-/,/, /„.<„,„, Hall. Turbinate, often curved. Septa numerous (80-130),
alternately long and short; the free edges of the longer septa are
t \vi-trd together ' ( , /(
in the centre to
form a pseudo-
coluinella. Tab-
ulae few or
alismt. Posi-

tion of the prin-
cipal septum is
ivrugnisable on
the exterior by
system of pin-
nately diverging
costal ridges.

Common in Ordo-
\iriaii and Sil-
urian.

FIG. 111.

nilcnsix, Bill. Hudson River group
(Oi'iluviciau); Cincinnati, Ohio. l/j. A, Side vi>-\v.
/.', Transverse section. C, Longitudinal section, (h, Car-
dinal sejituin; g, counter septum ; s, alar septum.)

f. (Figs. 111-114). Simple, turbinate, or sub -cylindrical,

- W TIG. 114.

r,,.. ii-j. Zdphrentis Enniskilleni, "Rich, ('ariioiiifernus Lime.

y.<ilthi-i:nti< n,riiiii;,j,;,n; snine; Ireland. .1, /;, Transverse sections tliroiigh re-

/"/'/" ?", Mieh. t'ali nlar-ed. spectively upper and lower portions of calicc. ' '. A Ion-

[..•>ueiir. Dev...nian lime- ( •iirl.onitVroiis Limestone; and two short septa united at the end* to form the wall.

-tone ; ohio. Ti.urnay, Helium. D, Longitudinal section showing tabulae (after Nicholson).

irer|iiently elongated. Calice deep, with circular margin. Septa numerous,
reaching to the centre ; cardinal septum in a deep fossula. Tabulae numerous,
somewhat irregular, and passing from side to side of the visceral chamber :

7fi COELEXTERATA — OX ID ARIA SUB-BRANCH n

dissepiments sparingly developed in outer zone of corallum. 50-60 species
known, ranging from Silurian to Carboniferous. Maximum development in
Carboniferous.

Amplexus, Sow. Simple, sub- cylindrical, or elongated turbinate. Calice
shallow, usually Avith septal fossulae. Septa moderately numerous, short, never
produced to centre. Tabulae highly developed, horizontal. Ordovician to
Carboniferous limestone.

Aulacophyllum, E. and H. Turbinate. Septa numerous, extending to
centre. Cardinal septum in deep fossula ; adjacent septa pinnately developed.
Ordovician to Devonian.

J/^o/;A/////////, E. and H. (Fig. 104). Turbinate. Cardinal septum in
largest of three fossula. Carboniferous limestone.

Lophophyllum. E. and H. Carboniferous limestone. Anisophyllam, E. and
H. Ordovician to Devonian. Pycnophyllum, Lindstr. Ordovician and Silurian.
Apasmophyllum, Roem. Metriophi/llurn, E. and H. Thamnophyllum, Penecke.
Devonian. Peiitapliyllum, de Koninck. Carboniferous.

Family 4. Cyathophyllidae. Milne-Ed\vards and Haime.

Simple or composite corolla. Septa numerous, radially arranged ; the four prin-
cipal septa rarely distinguished by greater or smaller size. Tabulae and veswulai
tissue (dissepiments) abundant.

Cyathophylhim, Goldf. (Figs. 115-117). Extremely variable in form,
sometimes simple, turbinate, or sub-cylindrical ; sometimes giving rise to

FiO.118.

l'!/iitlinplii/U.ii/n i-i/cx/iitdxii HI, Gull 1 1.

Devonian; Gerolstein, Eifel. Natural Cyathophyllum hemgonv.m, Goldf. Devonian; Gerol-

size. stein, Eifel. Natural size.

bushy, fasciculate, or astraeiform colonies, where reproduction takes place by
calicinal or lateral gemmation. Septa very numerous, strictly radial in arrange-
ment, and often alternately long and short ; the longer septa extending to the
centre. Visceral chamber filled with numerous imperfectly developed tabulae :
vesicular dissepiments highly developed in peripheral portion. Nearly 100
species known, ranging .from Ordovician to Carboniferous limestone Maxi-
mum development in Devonian.

si B-CLA88 I

ANTHOZOA— TETRACOBALLA ~~

i, E. and H. (Fig. 118). Like the preceding, but >cj»ta not
to the centre. Devonian and Carboniferous Limestone.

Hall. I'snally simple and turbinate, more rarely forming

|r

• rli/iH/iiit Ji'-ti-i-'ii'lii/Hum E. and H. .Middl
Devonian; Gerolstein, Eifel. ^4, Transverse ; /^Longi
tudinal section (after Nicholson).

Fi.;. 118.

< '<* in jHijili i/ll a m rnni-
/ * ri xxii in. Ludw. Car-
boniferous Limestone ;
Hausdorf, Silesia. u,
Longitudinal ; b, Trans-
verse section.

Fio. ll'J.

Diphyph

'•in, i a in, Lonsd.
Carboniferous
Li nic.st one; Ka-
nn-nsk, Ural.

dendroid colonies. Septa numerous, extending to the centre, and thickened
on their sides by conspicuous vertical ridges ("carinae "). Devonian.

l)ifilii()JiyUumt Lonsd. (Fig. 119). Ordovician to Carboniferous. PJ/ol /</<>-
1'iliyllum, Lindstr. Ordovician and Silurian. Eridophyttum, E. and H. Silurian

Uuttla

;uid Devonian.

E. and H. Silurian limestone;
", Side view ; 1>, Calice from above.

Lithoxt i otto*
,B.andH.

Carbon. Limcst. ;
Maiisdnrf, Sili-sia.
Sections of in-
dividual corallite
(after Knntli).

^ Dyb.
Carboniferous.

Devonian.

CrepidofJiyUiim, Xich.
Nich. Chona.w, E. and H.
Silurian to Carboniferous.

, Eaf. (Fig. 120). Corallum simple, conical, or turbinate ; th.-ra
with root-like processes. Septa numerous ; the four principal septa in shallow

\ >.ma.

COELENTERATA— CNIDABIA

SUB-BRANCH II

fossula. Surface marked with pinnately branching striae. Tabulae numerous.

Silurian.

Chonophyllum, E. and H. Silurian and Devonian.

Ptyctiaphyttvm, E. and H. Simple and turbinate, or composite. Each
stock is composed of funnel-shaped, invaginated
layers, representing calicinal buds, the marginal lips
of which are more or less reflected outwards. Septa
numerous and strongly twisted in the centre to form
a pseudo-columella ; their peripheral edges are thick-
ened and are fused with one another so as to form
a wall. Silurian (P. patellatum, Schlot. sp.) and
Devonian.

FIG. 122.

J.nitxiliilvin. Jlorifiinitix. Lolisd.
Carboniferous Limestone ; Kildare,
Ireland, l/i- a, Two cylindrical
corallites, partially split open ;
/'. Two hexagonal calices, seen from
above.

Phillipsustraea Hennahi, E. and H. Devonian limestone ; Ebersdorf,
Silesia. «, Upper surface ; I, Transverse section. Natural size.

Cydophylhim, Duncan and Thorn. Simple, cylindro-conical. Septa numer-
ous, the longer ones forming a thick pseudo-columella with enclosed spongy
tissue.

Aulophyllwn, E. and H., Aspidophyllum, fiJwdophyllum, Xich. and Thorns.,
etc. Carboniferous.

Ltifwstrotwn, Llwyd. (Stylaxis, M'Coy ; Petalaxis, E. and H.), (Fig. 121).
Fasciculate or astraeiform stocks composed of prismatic or cylindrical corallites.

FIG. 124.

Stauria n.<ii-neiforttiis, E. and H. Silurian; Gottland, Sweden. A, Transverse section^hrillel to upper
Mii-f'acr. 7J, Enlarged transverse section of individual corallitc. I'. Several calices from above. Natural >i/e
(after Nicholson).

Septa numerous, alternately long and short. Styliform columella in the centre.
Abundant in Carboniferous limestone.

Lonsdaleia, M'Coy (Fig. 122). Fasciculate or astraeiform, composite
coralla. Septa well developed ; columella large, composed of vertically rolled
lamellae. Central tabulate area bounded' by an interior dissepimental wall,

BUB-CLASS 1

A NTHOZOA— TETRACORA LLA

between which ;iin I tli«- thera vehicular endotheca is abundantly developed.

Common in Carboniferous rocks.

Sclnveiu.u- Astraeiforni storks composed of small prismatic

cMrallites. Septa e\t remely numerous. very slender, extending to the centre.
Theca imperfectly developed. Visceral chamber filled with infundibulit'orm
tabular and vesicular tixiir. Silurian (X. ///////x, M'Cuy sp.) and Devonian.
I'lif/tfiji/ifitlimi, S/titii</<>ji////!/niii, E. and 11. Silurian and I )«-\ oiiian.
.Irrmiltii-in, Srhweiuu. Astraeiform or bushy colonio. Septa stout and
numrrou-. S3T interior wall ifl present; taltidae are de\c]oped in the central
area, \\hile the perijdieral zone is filled with vesicular tissue. Silurian (. /.
>, Lin. sp.) and Devonian.

f, E. and H. (Fig. 123). Astraeiform colonies, with indi-

vidual corallites united l>y confluent septa, which are produced lieyond the
theca. and uhsciire the same. Interseptal loculi filled with vesicular endotheca.
I>e\oniaii and (arhoniferous.

Sfniir/n, E. and H. (Fig. 124). Astraeiform or bushy composite coral la.
Septa \\ell developed; the four principal septa characterised by larger size, and
forming a complete cross in centre of each corallite. Silurian (Wenlock).

Columnaria, Goklf. (Favistella, Hall). Astraeiform stocks, composed of
long, polygonal, thick- walled corallites. Septa radially arranged in two cycles,
alternately long and short, barely reaching the centre. Tabulae horizontal.
disposed at regular intervals apart, and stretching across the entire visceral
chamber. Dissepiments imperfectly developed or absent. Ordovician to
Devonian.

Heterophyllia, M'Coy. Carboniferous. Battersbyia, E. and H. Devonian.

Family 5. Cystiphyllidae. Milne-Edwards and Haiinc.

Usually simple corolla. Septa very thin ; interseptal loculi filial /'•////

or compact stereoplasma. Tabulae absent ; central
of visceral cJmmler either completely filled ivith vesicular
(„• stereoplasma, or containing the same only in the
lower portions of chamber. Calcareous operculum sometimes
present.

CystiphyUum, Lonsd. (Figs. 125, 126). Simple, very
rarely fofmTng bushy colonies. Calice deep; the entire
visceral chamber filled with vesicular tissue, which, as a
rule, wholly obliterates the numerous lineally directed
si -pi a. Silurian and Devonian.

>'//vy///^/r>, M'Coy (Fig. 127). Usually simple coralla.
Septa well developed, alternately long and short, some-
times forminj^a pseudo-columella. Silurian to Carbon-
iferous.

Goniophjmm, E. and H. (Fig. 128). Corallum simple,
in the form of a four-sided pyramid, and covered with
thick epithecal deposit. Calice deep; septa numerous,
thick and very short. Entire visceral chamber filled with
vesicular and stereoplasmic endotheca. Operculum com-
posed of four plates symmetrically paired. Silurian.

Rhizophyllum, Lindst. Corallum simple, pyramidal,

KK.. i •_•:,.
Cyitipkyll

<>[<.;1,'l1,'..ll sij!.''v""ia"

or hemispherical,

80

COELEXTERATA— CNIDARIA

SUB-BRANCH II

flattened on one side ; external surface corrugated, and sending off hollow,
root -like exothecal processes. Calice marked with septal striae ; internal

FIG. 126.

Cystiphyllum cylindricum, Lonsd. Silurian; Iron Bridge,
England. ^4, B, Transverse and longitudinal sections (after
Nicholson).

FIG. 127.

Strephodes Murchisoni, Lons.
Showing strongly developed
dissepiments and tabulae.

structure consisting of vesicular tissue and stereoplasma. Operculum in form

of semicircular plate ; inner sur-
face traversed by median ridge
and fainter, granulated, parallel
elevations. Silurian.

Calceola, Lam. (Fig. 129).
Corallum simple, semi -turbin ate.
or slipper-shaped, with one side
flat and triangular. Calice very
deep, extending nearly to apex,
and marked internally with fine
septal striae. Cardinal septum
placed in the centre of the vaulted
side, counter septum in middle of
flattened side, and alar septa at
the angles. Internal structure
composed of fine vesicular tissue
and stereoplasma. Operculum
semicircular, very thick, under

Calceola sandalina, Lam. , " .

Devonian; Eifei. Natural surface marked with prominent
median and fainter lateral septal
ridges. C. sandalina, Lam. Very common in Middle Devonian of Europe,
rare in Carboniferous Limestone of Belgium.

FIG. 128.

finii inpii /ill a at, pyramid'
ate, His. Sp. Silurian;
Gottland. A, Specimen
with operculum. B, Calice
seen from above. Natural
size (after Lindstrom).

FIG. 129.

Range and Distribution of the Tetracoralla.

The typical Tetracoralla are confined to the Palaeozoic rpfiks. They are
unknown in the Cambrian, and make their first appearance in the Ordovician,
where they are sparsely represented in North America and in Hfrope. Here
the most abundantly distributed genus is Streptelasma ; Cyathophyllum and
Ptychqphyttum being of rarer occurrence. The period of maximum development
falls in the Silurian, which contains the largest number of genera and species.
There are limestones found on the islands of Gottland and Dago (Esthonia), as
well as at Dudley, Shropshire, and at Lockport, New York, and other places in
North America, which are made up of ancient coral-reefs. The principal agents

BUB-CLASS II

ANTIIo/oA — I1K\.\< <»|;.\l.!..\

concerned in tin- fiiriiiatinii «it" i! //•<//,. //••liojtliyllum,

Oiii/ilti/iii", I'ti/i-lnifiliiflliiin, >'//-., //«/«*/• : .iiia, Auhir»jihi/llniii, Cyxti-

/ihl/lllllii. etc., <>f tlic T'fr'l'-","//'!, Koides llUIlleroi;

and Kchinodernis. Tin- / f"<-0raUa arc not ma in tin- \>

• •specially in the Middle and I n <>l the Kif.i

;. Mar/.. I '.onlo^n,-. Kn.u'land. and Nort: .ndant

here are the .u'eiiera 1'f/tith»/iltyllinn, < V//M//I,

. ,''»/'// /V/I//X Anifil'-niji, Lift

i, etc.. predominate in t he ( 'arlMHiifen.ii- I .inn-stone of B< ! :

Ireland, and North . \nieii. -a ; while in tin- Xn h-tein the >n|ifary x«'"U> i

/. ( )n the other hand, the iVrnio ( '.u -I,,,,, • . ,j the Salt

L'aiiLTf in l-'arther India and of the i-l;iml Timor contain the -,
./////</• ••/////////////. and L>,H»/II/. \ h. the .

(i'i<iinifi>.<fi/li.<, /'iiKtr,, ],/<,,//, mi, and Goecophytt\ ;IIL: in tl

lielun^ to tin- '/''f>;i'-"i-'i/l'' ; and to this ^r-iuji al>«» ha\c been assigned //o/oryx/ix,
K. and II., from the Cretaceous, and the recent genera /A/y/oy,//////!//,-.
and ti'iii/nin, Duncan. A numlier of Palaeozoic Tetrawralla, such a« /

.•lii/lli". and Sfnurin, are referred )>y Duncan and Nicholson to th<-

Sub-Class 2. HEXACORALLA. HaeckeL
(Zoantharia, Blainville ; //».»•./»•/////// and /V//</.Y/,,/,,, Klnvn berg.)

'e or composite pvliij*, "•>/// /w.AW ///<»///, /•/<.< »//•/>//"/ in cyd* -'
es of si. r • fr«jiii nf/i/ ii-'ifh riil/;i,
lint xiHiH-tiiiH'* jl.<h;i or with

83957 2759S8
:10 :12: 15:18:1 4:17: 1C : 11 : 11:1«:17:M JI:1

To the HexaCOi'iiUii belong the calcareous

buildiDg and deep-sea corals (.17
poraria) of the present day, the fleshy sea-
anemones (Ai-tiiiimi-i), and those forms
characterised by the secretion of a horny
axis (Jnti/Hifh'iri't). ( >f these three on
(jnly the MadnpOTQtia are kno\\-n in a fossil
These forms are di-t MIL: li-hed from
the T'trii'-»nilln by the lu-xann-ral system
and radial arrangement of m- - and

septa : and from tli> 100, in addition

to the abore-named characters, by their
simjile tentacles. In the M-nlf /"•n'ri". -i\g
oi- more rai'ely t\\el\e principal sej t;. spring

from the l)a|e of the theca, and bet \\een

ii

these new septa originate in >udi manner 'i,'.
that all similarly situate.! mesenteries be ;;;
come simultaneously provided with an

J '

130. •

Miln.-- K.lwnnU •!>>!
i th- II, j-

ti,

;;;;;;
"••" A

.... . n . mark *e beginning m

additional septum. The corallum, accord

in.icly, consists of at least six, but usually j"'j{ ^.VlTut'..'^'!"'^!-'- '
of a larger numl>er of septa, \\ hose disposi-

tion is strictly radial. The six principal septa form the first cycle, and at the
VOL. I <;

82 COELENTERATA — CXIDABIA SUB-BRANCH n

same time mark off the boundaries between which new cycles of successively six,
twelve, twenty-four septa, etc., are inserted. The septa of any cycle are usually
all of about the same length and thickness, those of the later cycles being almost
invariably of lesser proportions than those of the earlier. This law of septal
growth, however, which was first accurately determined by Milne-Edwards and
Haime (Fig. 130), is by no means strictly adhered to. Irregularities in the
growth of new septa may result in a penta-, hepta-, or octameral arrangement.
Reproduction takes place either sexually, when separate individuals are pro-
duced ; or asexually, by means of lateral or basal gemmation ; or by fission. In
composite coralla, the individual corallites are sometimes united by a common
coenenchyma. Endothecal structures are frequently present in the form of
synapticula, dissepiments, and tabulae.

The order of stone corals or Madreporaria (Zoantharia sclerodermata) was
divided by Milne-Edwards and Haime into five sub-orders : fiugosa, Tabulata,
Tubulosa, Perforata, and Aporosa. Of these, the Itugosa have been elevated by
Haeckel into a separate sub-class under the name of Tetracoralla. The groups
Aporosa and Perfomta are called Hexacoralla ; while the affinities of the Tabulate
(with which the Tubulosa are now generally included) are still unsatisfactorily
determined. The group is certainly composed of a varied assemblage of forms,
some of which have been assigned to the Hexacoralla, some to the Octocoralla,
and some to the Hydrozoa and Bryozoa.

[Miss Ogilvie, D.Sc., will shortly publish a work on the "Structure and
Classification of Corals," in which the subdivisions of the Madreporaria into
Tetracoralla and Hexacoralla are entirely abandoned, on the ground that the tetra-
meral septal system is merely an ancestral feature strongly marked in certain
of the older families, while hexameral septal symmetry is but one of many forms
of radial symmetry (pentameral, octameral, decameral, dodecameral, etc.),
developed in the course of time within this group of corals. The further sub-
division of Hexacoralla into Aporosa and Perforata is also discontinued by Miss
Ogilvie, who classifies the whole of the Madreporaria (" stone corals ") into a
number of families of equal rank. These are : — Zaphrentidae, Cyathophyllidae,
Amphiastraeidae (a new family of Palaeozoic — Recent age, including Stauria,
Columnaria, Pinacophyllum, AmpJiiastraea, Aplosmilia, Euphyllia, etc.), TurUnolidae
(including the Cyathaxonidae and Trochosmilinae), Oculinidae, Pocilloporidae (in-
cluding the Stylophorinae with the genera Astrocoenia and Stephanocoenia), Madre-
poridae (including the Turbinarinae), Stylinidae, Astraeidae (excluding the Eus-
milinae, Edw. and H.), Fungidae (including the Thamnastraeinae), Eupsammidae
(including the Stylophyllinae, Epistreptapliyllum, Diplaraea, etc.), Archaeocyathidae,
and Poritidae. — THE AUTHOR.]

•rder 1. MADREPtRARIA. Milne-Edwards.

Radially symmetrical sclerodermous corals with typically hexameral (rarely penta-
meral, heptameral, or octameral) arrangement of septa.

Sub-Order A. APfROSA. Milne-Edwards and Haime.

Septa and theca compact ; inter septal loculi usually partitioned off by dissepiments
oi' synaptioles, more rarely by tabulae, seldom empty throughout. Theca either in-
dependently secreted, or formed by fusion of the septal edges, or absent.

BUB-CLASS II

ANTILOZOA— HK.\ACOI;ALL.\

Family 1. Turbinolidoe. Milm-Jvlwarils un-l Halm.-.

( 'Hi-nil inn timjili; ni-ii .-, /</>.„! ,-niiifi'i.-il- '••//</, 'it/'/

'jit,il //«•////' r//////v ////v///y//"/'/. f V//////7/" "»/"////, /»/// <•//< n ,
Theca <;,m/>/, (»•.

The TurbinoKdat Ix-^in in the Juras>ie, and ai ily aliiiiiil.-uit iii tin-

T-'l'tiary and at tin- |>iv-mt <lay. S.-\ual ivpi . M luctimi |»M-\;iiU.
altlioii^h a few forms multiply liy ^••niniatioii ; tli«- l.ud-. h«»\\
r\cr, become separated from the part-lit animal at an
period.

Tni-l'iu"li<', Lam. ( Fiif. 131). Corallum five, eonieal. with
cireiilar ealiee. Sejita produeed outride the tli.-ra. Styliform

FIG. 131.

TH rlii inJiii HnnTi -
, E. and H.
Eocene; Highgate,
Kn-lau.l. 6/j.

182.

• .,<•/(//.>• duodielmooottabt*, Guiiir.

i:cm- ; l{;nli-n, IK-JIT Vicuna. Natural size.

'•on /.'.,/>..//,.
nn.l H M
nt-ar Vienna. Natural size.

columella present. Tertiary and Recent ; common in Calcaire Grossier of tho

1'ari- I'.asin, and Eocene of England.

Sfpkcnetrochtu, E. and H. Free, cuneiform, with don
uated calice ; columella foliaceous. Cretaceous to Recent.
N. rfi.^ni.^ Lam. Common in Calcaire Grossier of tin-
Paris Basin.

SiHilofrifliH.", K. and 11.; >7//A///v/r////>, From.; n,,,-hnt,-iH-liii.<.
Duncan. Cretaceous; Discotrochus, E. and H. Tertiary, etr.

<',,-<'f»fritchus, E. and H. (Fig. 132). Horn shaped ;

MCOnuhiS, Fnmi. Ajitian ;
H;iutc Manic. ,-, L'n.lilc, natural size ; t-ene ; I'or/.tcich, Moravia. .-, rrulilc, i.a! sw-tiun, nntural aizo

ltnlii'n.<, K. ami II-

I, Calii-c cnUirneil.

... . ,

natural si/c ; b, Calice cnlar-.-l.

young forms attached at the apex. Septa very numerous, produced
theca ; columella fasciculate. Cretaceous to Recent.

84 COELENTERATA — CX1DARIA SUB-BRANCH n

Flabellum, Lesson. (Fig. 133). Wedge-shaped, compressed, isolated, or
attached. Septa numerous. Wall covered with epitheca, and sometimes
furnished with spinous processes. Tertiary and Recent.

Trochocyathus, E. and H. (Fig. 134). Horn-shaped, with circular calice.
Septa stout; columella papillous and trabecular, and surrounded by several
cycles of pali. Numerous species from Lias to Recent.

Thecocyathus, E. and H. Depressed, conical, or discoidal, attached early in
life, later becoming free. Wall with thick epithecal investment. Calice
circular, septa numerous ; columella fasciculate, and surrounded by several
cycles of pali. Lias, Jurassic, Cretaceous, and Recent.

Paracyathus, Deltocyathus, E. and H. Tertiary and Recent. Discocyathus,
E. and H. Jurassic. Coenocyathus, Acanthocyathus, Bathycyathus, E. and H., etc.
Tertiary and Recent.

Caryophyllia, Stokes (Fig. 136). Turbinate, with broad base, attached.
Calice circular; columella papillous, trabecular, and surrounded by a single
cycle of pali. Cretaceous to Recent.

Family 2. Oculinidae. Milne-Edwards and Haime.

composite corolla, increasing by lateral gemmation. Walls of corallites
thickened by a compact coenenchyma. Lower portion of visceral chamber narroived
or filled up by deposition of stereoplasma. Septa moderately numerous ; interseptal
loculi usually open to the base. Lias to Recent; fossil forms not particularly
numerous.

Oculina, Lam. Corallites irregularly or spirally distributed over the smooth
surface of coenenchyma. Septa slightly projecting; columella papillous,
surrounded by cycle of pali. Tertiary and Recent.

Agathelia, Reuss. Like the preceding, but form-
ing tuberous or lobate colonies. Cretaceous and
Tertiary.

Synhelia, E. and H. Cretaceous. Astrohelia, E.
and H. Tertiary. Psammohelia, Euhelia, E. and H.,
etc. Jurassic.

Haplohelia, Reuss. Small, arborescent, with
corallites all disposed on one side of the branches.
Coenenchyma striated or granulated. Septa in
tnree cycles ; columella and pali present. Oligocene.
Enallohelia, E. and H. (Fig. 137). Stock
branching ; corallites disposed usually in alternating
sequence in two rows along the sides of branches. Coenenchyma highly
developed, striated, or granulated ; columella rudimentary. Jurassic.

Family 3. Pocilloporidae. Verrill.

Composite, branching, lobate, or massive colonies, with small cylindrical corallites,
united by compact coenenchyma. Septa few (6-24), sometimes rudimentary. Visceral
chamber partitioned off by horizontal tabulae.

Of the two recent genera belonging to this family, Pocillopora and Seriato-
pora, Lam., the former occurs also fossil in the Tertiary.

BUB-CLASS II

HEXACORALLA— APOE08A— ASTRAEIDAE

r.tniilx I. Stylophoridae. Milm- K.l\vard> ;m.| Maim.-.

_

,sVy//»/ n-,11 developed, forming // »•»////-,//
eohnneUa ; infir*i-/>fn/ Im-uli riii/if//

tlin>iiil/t<i,if. .Jurassic to lien-lit.

Mfili'jtliiH-n, Sehweii,'. (Ki^. 138).
Stock branching, in- depiv— ed.
ma->i\e. .uid tuberous. Caliees small,
embedded in abundant, at the surface
spinous, eoeneiiehyma. Septa well
de\el.,|)ed, niiHlerately numerous ;
Columella styliform. Jurassic, Ter-
tiary, and Ken'm.

AnuacU, Iv and IF. Kocene. St>/l"l»-lin, K. and H.

^ Family 5. Astraeidae. Milne- K.I wards and

< 'orattwn composite, or more rarely simple. Theca formed li/ fn*i<ni of >vy//,//
Septa numerous, usually well developed ; visceral eli<niil>/ r partitioned off by
moi'e or less abundantly developed dissepiments, more rarely bi/ tabulae. .]/>////'y ///<•<///"/<
ly budding or fission. Coi'allites of massive colonies usually reaching considerable
a If If iidi', n ad united with one another nthi-r <H redly by the walls or l;i ///<////>• of septa
exothei'ully produced (costal septa}.

Very abundant from the Trias onwards, and by far the most protean family
of all the Hexacoralla. According to the serrated or entire character of tin-
free septal edges, Milne-Edwards divides the Astraeidae into two sub-families —
the J.-ifi-ti.iiiHir and the

Still':,-! I.

Vifiiu.-i. ". Cunilluiii, natural si/-

Jurassic and ('r<

Sub-Family A. ASTKAKINAK. Milne-Edwards and Hainif.
septal edges tootJwd, serrated, »/• Insular.

a. Simple i-ornll'i.

Afontlivaultia, Lamx. (Fig. 139). Cylindrical, conical, turl>inatr, or dis-
. and cither acutely pointed, or broadly expanded at the l>a-r. Srpt.-i

-.nilHii c'iri/'>iiliiill<it<i, L-UIIX
; i':i.-n, C;ilva<!..>. 'Natuni! six.-.

. .-:

140.

:, 'ill in .^umi.sn, Fr-iin. N-
St. Dizi.T, Haut-Mariif. Natnra!

, upper edges serrated. Columella absent; epitheca thick, corrugated,
readily becoming detached. Common in Trisissie and Jurassic; somewhat rare
in Cretaceous and Tertiary.

LeptopliyUia, Keuss (Fig. 140). Like the preceding, but without epitheea,
and attached by broad base. Jurassic and Cretaceou-.

86

COELENTERATA— ANTHOZOA

SUB-BRANCH II

LitJwphyllia, E. and H.
Miocene and Recent.

Like the preceding, but with vesicular columella.

ft. Simple corolla or composite colonies multiplying l>y calicinal or marginal

gemmation.

Stylophyllum, Reuss. Corallum simple, either with or without calicinal or

marginal gemmation,

FIG. 141.

Stylocora exilis, Reuss
cene ; Niederieis

Mio-

or forming massive colonies. Septa stout, but only
inferiorly complete, terminating above in strong vertical
spines. Dissepiments vesicular ; wall covered with
epitheca. Alpine Trias.

Stylopliyllopsis, Freeh. Simple or imperfectly branch-
ing. Septa terminating near the centre in detached
vertical spines. Alpine Trias.

y. Busliy colonies multiplying by lateral gemmation.

Cladocora, Ehrbg. Corallum composed of long
Austria, cylindrical branches, free on all sides. Calice circular ;
septa well developed ; columella papillous ; cycle of pali
present. Jurassic to Recent.

Stylocora, Reuss (Fig. 141). Branches cylindrical; septa stout, those of the
first cycle with columnar thickenings on inner edges ; columella styliform.
Cretaceous and Miocene.

Pleurocora, E. and H. Cretaceous. Goniocora, E. and H. Triassic and
Jurassic.

8. Composite corallites multiplying by basal gemmation ; buds arising from stolons

or basal expansions.

Pihizangia, E. and H. (Fig. 142). Corallites united by short, sub-cylindrical

stolons. X^alices shallow, circular; columella papillous. Cretaceous and Tertiary.

Latusastraea, d'Orb. Corallites arising from common basal expansion, short

FIG. 142.

Rhizangia Michelini, Reuss.
Middle Cretaceous ; Gosau Valley,
Austria. Natural size (after Reuss).

FIG. 143.

Cladangla conferta, Reuss. Miocene ; Bischof-
swart, Moravia. a, Corallum, natural size ;
1), Calice enlarged (after Reuss).

and strongly inclined to one side, so that the calices acquire a semicircular
contour and assume the form of protruded lips. Jurassic and Cretaceous.

Astrangia, Cryptangia, Phyllangia, dadangia, Ulangia, E. and H, etc.
Tertiary and Recent.

€. Massive coralla multiplying by lateral gemmation.

Heliastraea, E. and H. (Fig. 144). Cylindrical corallites united by exothecally
produced, confluent, costal septa. Columella spongy ; dissepiments numerous
between the septa both within and exterior to the theca. Jurassic to Recent.

.SUB-CI.A-- II

1 1 1:.\ ACORALLA— APOROSA— ASTRAEIDAE

87

with
poly-
imperfect
to Cre-

Fn>m. Like tin- pivrrdin«j, l.nt with s.-v.-ral
all the cycles excepting the
last. Tertiary :nnl

/.<ii.<friirn, ]•]. and H.
II"'). Corallites prismatic
closely crowded, and
fused walls. Calices
gonal ; columella
or absent. Trias
taceous.

Latimacandra, d'Orb. (Fig.
146). Like the preceding,
hut with the calices situated
in short furrows. Trias to
Cretaceous.

From. Lias.
From. Upper

• Jurassic. Leptastraea, Solen-
astraea, Prionastraea, E. and H.,
etc. Tertiary and Recent.

pali in front of

Fio. 145.

laastnua hel'uinthcdile*, Goldf.
s|.. < 'oral -Rag; Nattheiin.
Natural size.

^[ass^ve coralla multiplying
ssion.

Vm. 144.

Kin. 140.

Lutlmaeandra seriata,
Ueck. Coral-Kax: Nati-
lieiin. Natural size
(after Becker).

Oken (Fig. 147).

Corallum massive ; Calices Vienna, a, Corallum, natural

oval or distorted, and united

by confluent costal septa ; columella spongy. Jurassic to Recent.

Goniastraea, E. and H. Corallites prismatic, calices polygonal. Septa well

Pia 147.

"i-il

From. Coral-Rag; Natt-
lieiin. Natural size.

Fio. 148.

Stokem, E. and H.
; Sti-eple Ashton, England.
Natural six.-.

FIG. 140.

TkeeotmUia

CJoMf. sp. Coral-Raw ; Natt-
IMMIII. Natural si/f.

developed ; columella spongy ; pali in front of all cycles excepting the last.
Cretaceous to Recent.

?/. Branching coralla multiplying by fission.

Cdlamophyllia, Blainv. (Rhabdophyttia, E. and H. ; LUJwdendron, p. p. Mich.),
(Fig. 148). Colony fasciculate or bushy; corallites very long, cylindrical.

88

COELENTERATA— ANTHOZOA

SUB-BRANCH II

Wall costate, without epitheca ; columella absent. Trias, Jurassic, and Ter-
tiury. Especially common in Alpine Trias. C. clathrata, Emmrich sp.

Thecosmtiia, E. and H. (Fig. 149). Colony bushy, calices dividing by fission,
and more or less free. Epitheca corrugated, readily wearing away ; columella
absent or rudimentary. Trias to Tertiary. According to Freeh identical with
Calamophyllia. Very common in Triassic and Jurassic.

Barypliyllia, From. Hymenophyllia, E. and H., etc. Cretaceous.

6. Corolla, with confluent calices increasing ly fission.

Leptoria, E. and H. (Fig. 150). Corallum massive, composed of labyrinthic
rows of confluent corallites with fused walls. Septa closely crowded, approach-
ing parallelism ; columella f oliaceous.
Jurassic to Tertiary.

Diploria, E. and H. Like the
preceding, but with corallites united
i iiili£ JE»^£1 by produced costal septa instead of
directly by their walls. Cretaceous
to Recent.

Aspidiscus, Konig. (Fig. 151).
Corallum discoidal, circular, or
FIG. 150. elliptical, covered on lower side

Aspidiscus cnstutits, . f . , , , . , ~ ,. . .

Leptoria Konincki, Renss. Konig. Middle Greta- With Wrinkled epitheca. CallCinal

NKiCsrffeace°Us;G( luValley' NZSraiBsaizea'AIgeria' furrows radiating from the centre

outwards, and separated from one

another by sharply crested ridges. In the centrifugally disposed corallites the
outermost septa are thickened, and form by their union a banded margin.
Cretaceous.

Stiboria, Etall. Jurassic. Stelloi-ia, d'Orb. Cretaceous. Maeandrina, Lam.
Cretaceous to Recent. SymphylUa, E. and H. Tertiary and Recent.

Sub-Family B. EUSMILIINAE. Milne-Edwards and Haime.
Upper septal edges entire, not serrated.

a. Simple coralla.
Trochosmilia, E. and H. (Fig. 152). Turbinate, base acutely pointed or

FIG. 152.

Trochosmilia granifera, Raiine. Tnronian ; Bains-de-
Rennes, France, a, Profile ; b, Calice slightly enlarged
(after Fromentel).

loan.

E. and H. White
Chalk ; Luneburg,
llanovcr. Natural
size.

FIG. 154.

PlacosmUia cuneiform b, K.
and H. Upper Cretaceous ;
St. Gilgen on Wolfgangsee,
Austria. Natural size.

encrusting. Septa numerous, extending to the centre. AVall without epitheca,

BUB-CLASS II

II KX A< 'OKA LLA— A 1>< >K< )SA— ASTRA Kl I >A K

Bfi

costae granulated. Colnmella absent, dissepiments nuincn.u-. ( 'ivtarrous and
Tertiary.

Coelosmilia, E. and H. (Fig. 153). Like the preceding, but with dis.-rpi
ments sparsely developed. Cretaceous and Recent.

Placoxiuiliit, K. and H. (Fig. 154). Cuneiform, I wise acutely pointed or
slightly pedunculate. Calice laterally compressed, elongated. Septa numerous ;
dissepiments abundant; columella foliaceous. Epitheca absent; costae granu-
lated. Cretaceous.

J>ijilni-fi-iiiiini, Goldf. Calice laterally compressed, greatly elongated in
transverse direction, and bent downwards at the ends so as to become crescent-
shaped. Columella and epitheca absent. Costae dichotomously or trieho-
tomously furcate. Upper Cretaceous.

Axosmilia, E. and H. Jurassic. Phyllosmilia, From. Cretaceous. LH/>!">-
Hin. K. and H. Cretaceous and Recent.

/?. Coralla multiplying by lateral gemmation.

Placophyllia, d'Orb. (Fig. 155). Buds originating on calicinal margin or
sides, and giving rise to bushy or massive colonies. Columella styliform.
Jurassic.

Gahixea, Oken. Bushy colonies with cylindrical corallites united by layers
of finely vesicular epitheca (peritheca). Recent.

Stijlina, Lam. (Fig. 156). Massive colonies, with corallites united by co-
alescent costae. Septa well developed, disposed in six, eight, or ten cycles.

GoMf. sp.

Nattliciin. a, Coialluni,
natural sixc ; b, (.'alice ei

Still!

Ashtoii, England.
enlarged.

Fit;. 150.

, E. and H. Coral-Ilag ; Steeple
c, Natural six.- ; /-, C'alices

Dissepiments numerous ; columella styliform. Multiplication by costal gemma-
tion. Profuse in Trias, Jurassic, and Cretaceous.

Placocoenia, d'Orb ; On/ptocoenia, E. and H. Jurassic and Cretaceous.

<'t/'ifltojt/tt>i-a, Mich. Massive colonies, with corallites united by costae.
Septa short, not reaching the centre ; columella absent. Visceral chamber
partitioned off by horizontal tabulae. Jurassic and Cretaceous.

Coccophyttum, Reuss. Massive colonies, with corallites united directly by
their walls. Calices polygonal, septa numerous. Columella absent; visceral
chamber tabulated. Alpine Trias.

Pinacopkyllum, Freeh. Triassic.

Hoiocystis, Lonsd. Massive colonies, Avith corallites united by costae. Four
of the septa larger or stouter than the rest. Tabulae in visceral chamber.
Cretaceous.

90

COELENTERATA— ANTHOZOA

SUB-BRANCH II

Astrocoenia, E. and H. (Fig. 157). Massive colonies. Corallites polygonal,
united by their walls; septa numerous, long. Columella stylif orm ; only

dissepiments present in visceral
chamber. Trias to Tertiary.

Stephanocoenia, E. and H.
Like the preceding, but with
columella surrounded by cycle of
pali. Trias to Recent.

Phyllocoenia, E. and H. (Con-
fusastraea, d'Orb. ; Adelastraea,

FIG. 157. Reuss). Massive colonies. Coral-

lites round or oval, imperfectly
united by costae. Septa strongly
developed, thickened in the middle between theca and the centre. Columella
rudimentary. Trias to Tertiary.

Convexastraea, d'Orb. ; Trias to Cretaceous. Colnmnastraea, Stylocoenia, E.
and H., etc. ; Cretaceous and Tertiary.

y. Coralla multiplying by fission.

Haplosmilia, d'Orb. Bushy colonies. Corallites usually with tlichotomously
dividing crests. Calices circular or elongated ; columella styliform ; theca with
ridge-like costae. Jurassic.

Plocophyllia, Reuss (Fig. 158). Branching, foliaceous, or massive colonies.

Astrocoenici decaphylla, E. and H. Upper Cretaceous ; Gosau
Valley, Austria, a, Coralluin, natural size ; I, Calices enlarged.

FIG. 158.

Plocophyllia (xdyculata, Reuss. Oligocene ; Monte
Carlotta, near Vicenza. Natural size.

FIG. 150.

I!li!)iiili>;/!ira crassa, From. Coral - Rag ; Gray,
Haute-Saone. i/a natural size.

Corallites either becoming free or grouped into detached rows. Columella
absent. Tertiary.

BarysmUia, E. and H. Corallum massive, forming a thick stem, the apex
of which is covered with short buds. Calices oval, sometimes disposed in
series ; columella rudimentary. Cretaceous.

Stenosmilia, From. Like the preceding, but with lamellar columella.
Cretaceous.

Pachygym, E. and H. Corallites arranged in winding rows, and united by

SUB-CLASS II

II KXA< 'ORALLA— APOROSA— FUNGIDAE

91

broad mass of costal coenenchyma. Columella lamellar. Jurassic and
Cretaceous.

d'Orb. Jurassic and Cretaceous.

i, K. and 11. (Fig. 159). Corallum fan-shaped, often corrugated,
and with but a single calicular furrow. Columella lamellar. Jurassic and
Cretaceous.

Family 6. Fungfidae. Milne-Edwards and Haime.

Simple, coralla, or low, laterally expanding colonies. Septa numerous, upper edges
synaptimlti (rawly also dissepiments) between the septa. Wall between
rorallites absent, but
developed on under side of
i-ulinti,*. Reproduction sexual

<>r //;/ gemmation. Jurassic to b

Recent.

/•'n/i;tin, Lam. p.p. emend.
Dana. Corallum simple, de-
pressed, discoidal. Septa very
numerous, varying in length
and thickness, united only by
synapticula, and projecting on
the lower side as dentated
costae. Theca absent. Post-
pliocene and Recent.

Microseris, From. (Fig.
160). Corallum simple, dis-
'•<>idal, circular; upper side vaulted, lower flat and granulated.

Trochoseris, E. and H. Tertiary and Recent.

Cyathoseris, E. and H. (Fig. 161). Corallum turbinate, attached.

FIG. 160.

Microseris hemisphaerica, From. Greensand (Cenomanian); Le
Mans, France, a and 6, Upper and lower surfaces, enlarged ;
c, Profile, natural size.

Cretaceous.

Young

FIG. 101.

OtfOfkottri$ tubregvJarts, Ri-uss. Miocene; Monte Carlotta, near Viccnza, Italy.
a, Top view ; b, Side view, natural si/f.

• •i.rallitrs arising from periphery by costal gemmation. Common outer wall
naked, striated. Cretaceous and Tertiary.

Lophoseris, E. and H. ; Mycedium, Oken ; Agaricia, Lam., etc. Tertiary and
Recent.

COELENTERATA— ANTHOZOA

SUB-BRANCH II

Sub-Order B. PERFOBATA. Milne-Edwards and Haime.

built up of small calcareous bodies (sclerites), between which are empty
interstices of greater or lesser size. Theca formed by fusion of outer septal edges or
absent. Interseptal loculi empty throughout or traversed by synapticula or dissepiments.

? Family 1. Archaeocyathidae.1 Walcott.

Simple, turbinate, or sub -cylindrical corolla. Septa and theca porous ; inner
septal edges united by perforated interior wall, which encloses a hollow central space.
Synapticula present in interseptal loculi.

All the genera described up to the present time (Archaeocyathus, Bill. ;
Ethmophyllum, Meek; Spirocyathus, Hinde; Protopharetra, Bornem., etc.) are
restricted to the Cambrian rocks of Canada, North America, Spain, and
Sardinia. They represent possibly a distinct order of the Madreporarm.

Family 2. Eupsaxnmidae. Milne-Edwards and Haime.

Corallum simple or becoming composite by lateral gemmation. Septa rery
numerous, sometimes united by synapticula, and frequently with their inner edges
fused together. Theca naked or covered with epitheca, and formed by thickening of the
septal edges. Silurian to Recent.

Calostylis, Linds. Corallum simple, sub - cylindrical, or composite and
multiplying by lateral gemmation. Septa very numerous, of spongy con-

Eupgammla

.trochiformis,
Pallas. Cal-
caire Grossicr ;
Chaussy, near
Paris. Natural
size.

\'i<;. 1(>3.

Hnlinii>iili i/lliii- ximiala, Reuss.
Oligocene ; Waldbockelheim,
Prussia. a, Natural size;
b, Number of septa enlarged.

FIG. 164.

sti-iiliiin<ii>1mUia elegans, Bronn sp. Pliocene;
Stazzano, near Modena, Italy, a and b, Upper
and lower surfaces, enlarged; c, Profile, natural

sistency, and either fused together or united by synapticula. Columella thick,
spongy ; wall covered with epitheca. Silurian ; Gottland.

Haplaraea, Milasch. Simple, cylindrical coralla, with broad encrusting base.
Septa numerous, extending to the centre, perforated by large apertures, and
sometimes fused together or united by synapticula. Traversa also present, but
no columella. Jurassic and Cretaceous.

1 Sittings, K, Palaeozoic Fossils of Canada, I., 1861-65.— Walcott, C. 7A, Bull. U. S. Geol.
Survey, No. 30, 1886. — Bornemann, J. G., Versteinerungeu des Camlirisclieu Systems von Sardinieii,
1886.— Hinde, G. J., Quart. Journ. Geol. Soc. vol. XLV., 1889, p. 125.

UM ,, HKXAmlJALLA—PERFORATA !>3

/;//y;.>v/,,, //</,/, E. and H. (Fig. 162). Conical or turbinate, acutely pointed.

Septa very numerous, arranged in five cycles, those of the last cycle

-touter than the rest. Columella jut-sent or absent.

Eocene to Recent.

i;,il,n,n/,liiillw. Wood (Fig. 163). Simple, sub-
evlindrieal, with broad encrusting base. Columella
spoiii^v; septa closely crowded, partly fused together.
Eocene to Recent.

Stephanophyllw, Mich. (Fig. ^

164). Simple, discoidal; base
horizontal, calice circular. Septa
numerous ; the six principal septa
extending to the centre, the re- „
mainder with fused inner edges.
(Vetaeeoiis and Tertiary.

/>,;,,l,-<'i>hr/Ilia, Blv. (Fig. 165).
Corallum branching, increasing
l»v lateral gemmation. Calices
oval ; septa numerous and slender,
those of the last cycle extending
to the spongy columella, and fused with the converging ends of shorter septa
of preceding cycle. Tertiary and Recent.

Lobopsammia, Stereopsammia, E. and H. ; Eocene. Astroides, E. and H. ;
Keeent.

Family 3. Thamnastraeidae. Reuss.

(Pseudoastraeidae and Pseudoagaricinae, Pratz.)

Simple corolla, or composite, basally expanded or massive colonies. Septa numer-
ous, move or less perforate, and composed of calcareous bodies (trabeculae) arranged in

FIG. 165.
Dendrophyllia . elegans, Duncan. Oligocene ; Brockenlmrst,

5' Trausv"rs" s"rti""

natural size

FIG. 166.

Lam. Ujipfr Cr<'t;icc,,us ; (iosau Valley, Salzkaininergut. «., Side view ;
&, Lower surface ; c, Lateral aspect of septum, natural size.

vi i-finil or fan-shaped rows. Theca between individual corallites absent, but present on
under side of corallites or on lower side of the common stock Interseptal loculi with
xi/iHi/iticulae and dissepiments. Abundant from Trias to Cretaceous ; rarer in
Tertiary and Recent.

Anabacia, E. and H. Simple, free, discoidal, or lenticular coralla, with flat
base. Upper side vaulted, calice slit-like. Septa very numerous, thin, and
united by synapticulae. Theca absent. Jurassic.

94

COELENTEKATA— ANTHOZOA

SUB-BRANCH II

Genabacia, E. and H. Like the preceding but composite, the central calice
being surrounded by a row of smaller calices. Jurassic.

Micrabacia, E. and H. Cretaceous.

Omphalophyllia, Laube. Simple, turbinate, or sub-cylindrical, attached, and
covered with epitheca. Septa very numerous, upper edges granulated. Calice
shallow, columella styliform. Alpine Trias.

Cyclolites, Lam. (Fig. 166). Simple, free, discoidal, upper side vaulted,
lower flat and covered with corrugated epitheca. Septa very thin, extending

FIG. 167.

Tliii-,itn(istraea prolifera, Becker. Upper Jurassic ; Nattheiin, Wiirttemberg. A, Corallum, 2/3 natural size;
w, Common wall. B, Lateral surface of costal septum, enlarged (8/j), showing trabecular constitution ; m, Line
of junction of two septa belonging to different corallites ; t, Trabeculae ; p, Trabecular lacunae (after Pratz).
C, Thamiti'xtrttni. ni/in-ii-ites, Goldf. Upper Cretaceous; Gosau, Salzkammergut. Portion of upper surface of
corallmn, natural size.

to the centre, extremely numerous, composed of vertical rows of trabeculae, and
united by synapticulae and dissepiments. Very abundant in Cretaceous, rare
in Jurassic and Eocene.

Thamnastraea, Le Sauvage (Fig. 167). Composite, laterally expanded and
pedunculate, or mushroom-shaped coralla. Common wall restricted to lower

side of corallum ; individual corallites without
proper walls, but united by costal septa.
Columella styliform or rudimentary. Septa
well developed, composed of fan-shaped rows
of cylindrical trabeculae, and united by synap-
ticulae and dissepiments. Very abundant
from Trias to Oligocene.

Dimorphastraea, d'Orb. Like the preced-
ing, but with calices concentrically arranged
about a central individual. Trias to Tertiary.
Comoseris, d'Orb. (Fig. 168). Like T/iam-
•nastraea, but with calices separated into groups
by ascending fiexuous ridges. Jurassic and
Tertiary.

Astraeomorpha, Reuss. Coralla composite,
tuberous, basally expanded, or branching,
and covered with corrugated epitheca. Corallites small, united by short and
stout costal septa ; columella styliform. Trias to Oligocene.

Microsolena, Lamx. ; Trias and Jurassic. Dimorpharaea, From. ; Jurassic.

Fig. 1G8.

Comoseris conferta, Reuss. Oligocene ;
Monte Carlotta, naer Vicenza. Twice en-
larged.

BUB-C LA88 I!

1 1 1:.\ ACORALLA— POEITIDAE

95

Family 4. Poritidae. Duna.

Composite corolla composed of 2)orous sclerenchyma. Corallites small ; septa as a
ride only moderately numerous, sometimes represented by rows of trabeculae or lamellae.
Theca absent.

Sub-Family A. SPONGiOMORPHiNAt:. Freeh.

CoraKum composed of thick trabeculae and strengthened by horizontal synapticulae.
Calices very imperfectly differentiated from coenenchyma, and without distinct septa.
Dissepiments usually *jntrsely developed.

Of the genera belonging to this sub-family, Spongiomorpha, Heptastylis, and
Stromatomorpha, Freeh, are found in the Alpine Trias (Rhaetic and Zlambach
Schichten). These are all tuberous, composite coralla of extremely irregular
form. In Spongiomorpha and Heptastylis, six septa are indicated by somewhat
regularly disposed columns of trabeculae ; and in the latter form these' are
bound together by synapticulae which are projected at equal altitudes, and
form perforated horizontal storeys. In Stromatomorpha no radial arrangement
of the trabecular septa exists.

Palaeacis, E. and H. (Sphenopoterium, Meek and Worth), occurring in the
Carboniferous limestone of North America and Scotland, possibly also belongs
here.

Sub-Family B. TURBINARINAE. Milne-Edwards and Haime.
Septa well developed, compact. Corallites embedded in canaliculated coenenchyma.

Actinacis, d'Orb. (Fig. 169). Massive or branching coralla. Coenenchyma
abundant, granulated ; septa stout, of nearly uniform proportions, columella
papillous ; pali in front of all the septa. Cretaceous and Tertiary.

FIG. 169.

FIG. 170.

Actinacis eleyu //>•, Hciiss. Upper Cretaceous ; Gosau
Valley, Balzkammetgat. «, Upper surface, natural Lithuraeu Websteri, Bowerb. sp. Eocene ; Brackles-

size ; b, Transverse section, enlarged ; c, Longitudinal ham Bay, England, a, Coralluiu, natural size ; b, Four

section, enlarged (after Reuss). calices enlarged.

Astraeopora, Blv. Massive coralla. Coenenchyma porous and on upper
surface echinulate. Septa of dissimilar proportions ; columella and pali absent.
Tertiary and Recent.

Dendracis, E. and H. ; Cryptaxis, Reuss. Tertiary.

Turbinaria, Oken (Gemmipora, Blv.) Corallum foliaceous. Coenenchyma
tolerably compact and finely echinulate. Septa of similar proportions ;
columella spongy. Cretaceous to Recent.

96

COELENTERATA-~ANTHOZOA

SUB-BRANCH II

Sub-Family C. PORITINAE. Milne-Edwards and Haime.
>Vy//V mil nrii numerous, well developed. Corallites united by their porous walls.

Litharaea, E. and H. (Fig. 170). Massive coralla. Calices sub-polygonal;
septa generally in three cycles ; columella spongy. Eocene and Miocene.

Pihodaraea, E. and H. Massive coralla. Spurious walls of corallites thick ;
pali prominent. Miocene and Eecent.

Porites, Lam. (Fig. 171). Massive or branching coralla. Calices shallow,
polygonal ; septa irregularly reticulated ; columella papillous, surrounded by

Fio. 171.

Porites incrustans, Reuss. Miocene;
Moravia. a, Transverse section ;
b, Longitudinal section. Both figures
highly magnified.

FIG. 172.

«, Alveopora spongiosu, Dana. Recent; Fiji Islands.
Longitudinal section of corallite showing perforate Avails
and tabulae; b, Alveopora ntdis, Reuss. Nununulitic lime-
stone ; Oberburg, Styria, 1/1 ; c, Calices, greatly enlar^-d.
(Fig. a, after Dana ; b, after Reuss).

single cycle of pali. Cretaceous to Recent. The genus Porites is one of the
most important of existing reef-builders.

Protaraea and Stylaraea, E. and H. Usually encrusting coralla with poly-
gonal calices. Visceral chambers partitioned off by horizontal tabulae. Silurian
and Devonian.

Sub-Family D. ALVEOPORINAE. Verrill.

Septa composed of detached trabeculae, spines, or reticulated lamellae. T/teca
perforate. Visceral cluimber ivith perforate tabulae.

Alveopora, Quoy and Gaim. (Fig. 172). Massive coralla. Calices small,
polygonal. Septa represented by detached spinous processes. Tabulae sparsely
developed, remotely situated. Tertiary and Recent.

Koninckia, E. and H. Cretaceous.

Family 5. Madreporidae. Dana.

Composite, branching, or lobate coralla with small tubiform corallites embedded in
a canaliculated and reticulated coenenchyma. Septa (6-12) sometimes imperfectly
developed. Two long septa projected from opposite sides and meeting in the centre.

The genus Madrepora, Lin. (Fig. 173), is an important agent in the con-
struction of existing coral reefs, and builds colonies sometimes of considerable
size. It occurs sparsely in the fossil state in the Tertiary.

Range and Distribution of the Hexacoralla.

The group Aporosa of the Hexacoralla appears to have originated from the
Tetracoralla, and to form the direct continuation of their line. They begin as

BUB-CLAM ii IIKXACORALLA— PORITIDAE 97

the latter disappear; they develop a great variety of forms in the Trias, and
from the Mesozoic clown to the present day they have continued to play a
leading part in the construction of coral-reefs. Of the six families constituting
the Aporosa, the .htr<ni<l,i<- is by all odds the most important and most protean,
in comparison to which the Fungidae, Stylopkoricfae, PocUloporidae, Oculinidae,
and Tin-l'iiii'UilfH' fall into greatly subordinate rank. The other families are all
vounger than the ^Idrm-iilfU', not beginning until the Jurassic, the Pocillopoi'idae,
indeed, not until the Tertiary.

The Perforata constitute a well -denned branch of the Hexacoralla, whose
ancestry may perhaps be sought in the remarkable Archaeocyathidae of the
Cambrian. The I^iij>^iinmidae and Poritidae occur sporadically in the Silurian
and Carl M.I i if. -nms, while it is not until the Trias that the Thamnastraeidae and
llnrit'nl'n> develop a large variety of forms; from the Trias to the Tertiary,
however, these genera continue to be important reef-builders. The Eupsam-
inidae attain their greatest development in the Tertiary and Recent, while the
Ufadrdporidae belong almost exclusively to the present period.

Occasional isolated deep-sea forms are met with in most of the several
geological periods, but the usual mode of occurrence of the HexacoraMa is

•iated in masses in coralline limestones ;
the limestones may be of very variable
thicknesses, but as a rule are interstratified
between deposits of distinctly littoral
character. Ancient coral-reefs most nearly
resemble modern fringing or barrier reefs,
but not atolls, the origin of which is clearly
dependent upon the peculiar orographic FIG. 173.

Conditions of the Pacific Ocean. .V.»//Tporo Anglim, Duncan. Oligocene ;

TViP <iif faeeian 71amKanVi nnrl T?h<iAtin Brockenhurst, England, a, Calices enlarged ;
t. ^aSSian, ZaamDacn, ana ItnaetlC b> Longitudinal section, greatly enlarged.

beds of the Alpine Trias contain* large

numbers of reef -building Hexacoi'alla ; but the pure limestones and dolomites
of the Alps, as well as the Trias outside the Alpine region, are frequently
either almost or entirely destitute of coralline remains.

In the Lias coral-reefs have been found in England, Luxemburg, and
Lorraine. Certain beds of the Dogger, usually of but meagre thickness, are
occasionally charged with corals, as in Swabia, the Rhine valley in Baden, the
Swiss .Jura, Normandy, and England. Coralline limestones are abundantly
developed in the Upper Jurassic of the Jura Mountains in France and Switzer-
land, in Lorraine, Southern Baden, Swabia (Nattheim, Blaubeuern), Bavaria
( Kelheim), many places in France and England, as well as in the whole province
of the Alps, Carpathians, CeVennes, and Apennines ; here the uppermost
horizon (Tithonian) is especially characterised by their development.

In the Lower Cretaceous (Neocomian) coral-reefs are found in France
(Haute-Marne and Yonne), Crimea, and Mexico; while the Urgonian of
Switzerland and the Bavarian Alps is occasionally charged with corals. In the
Turonian and Senonian of the Alps (Gosau Beds), Pyrenees, and the Provence,
numerous coral-reefs occur, usually accompanied by Rudistae ; elsewhere, how-
ever, except in Holland (Maestricht) and Denmark (Faxoe), the Upper
Cretaceous contains but a limited number of reef-building Hexacoralla.

In the older Tertiary (Eocene and Oligocene) the occurrence of coral-reefs
is restricted to the northern and southern flanks of the Alps and Pyrenees,

VOL. I H

98 COELENTERATA— ANTHOZOA SUB-BRANCH n

Arabia and the AVest Indies ; while outside the Alps in Europe and in America
their distribution is mostly sporadic. In the Miocene and Pliocene the true
coral-reefs retreat more and more towards the equator (Red Sea, Java, Japan),
while the Hexacwalla which persist in formations of the temperate zone
(Vienna Basin, Italy, Touraine) constitute but an insignificant feature of the
general fauna.

Appendix to the Hexacoralla.

Sub-Order C. TABULATA.1 Milne-Edwards and Haime.

Invariably composite corolla composed of tuUform or prismatic corallites. Walls
thick, independently calcified, compact, or perforated by connecting mural pores. Septa
but slightly developed (usually six or twelve), sometimes represented merely by vertical
ridges or rows of spines, and sometimes entirely absent. Visceral chamber partitioned
off into successive storeys by tabulae. Synapticulae and dissepiments wanting.

To the Tabulata were originally assigned by Milne-Edwards and Haime all
corals having numerous tabulae and rudimentary septa. Later researches have
shown, however, that some of these forms (e.g. Pocilloporidae) belong to the
Aporosa, others (Heliopoiidae) to the Octocoralla, and still others (Millepora) to
the Hydrozoa ; while the affinities of a few (Chaetitidae, Monticuliporidae) are of
such doubtful nature as to be referred by some authors to the Corals, and by
others to the Bryozoans. The majority of the typical Tabulata (Favositidae,
Syringoporidae, Halysitidae) exhibit close relationships to the Hexacoralla; but
since they are for the most part now extinct and are largely confined to the
Palaeozoic rocks, the positive determination of their systematic position seems
almost hopeless. The ontogeny of the corallites in the Tabulata shows that the
development of mural pores is homologous with the process of gemmation.
Reproduction sometimes takes place by fission, but generally by means of buds
from the edges of the calices at various stages during the growth of the parent
corallites. Buds are given oft' early in Aulepora, producing basal corallites only ;
periodically in Romingeria, producing verticils of corallites ; periodically and on
one side in Halysites, producing linear series of adjacent corallites ; and very
frequently in Favosites, etc., producing compact coralla with numerous mural
pores representing aborted buds.

Family 1. Favositidae. Milne-Edwards and Haime.

Massive w branching coralla. Corallites uniformly piismatic, tall, and united by
their walls, which are perforated by large -sized pores. Septa very short, usually
represented by but faintly projecting ridges or rows of spines, but seldom completely
absent. Tabulae numerous, situated at regular intervals, complete and horizontal,
more rarely oblique or irregularly vesicular ("cystoid").

The Favositidae are distinguished from the Poritidae, with which Verrill
associates them, by their thick, solid walls, which are punctured by round,

1 Lindstrom, G., Affinities of the Anthozoa Tabulata (Ann. Mag. Nat. Hist. Ser. 4, XVIII.), 1876.
— /ti/ftuwski, W., Die Chaetitiden der ostbaltischen Silurformation (Verb, der k. russ. min. Gesi-llscli.
St. Petersburg), 1877. — Nicholson, H. A., On the Structure and Affinities of the Tabulate Corals of 1 lit-
Palaeozoic Period. London, 1879. — On the Structure and Affinities of the genus Monticulipora.
London, 1881. — Roemer, F., Lethaea Palaeozoica, I., 1883, p. 416. — Waagen, IF., and Wentzd, 11'..
The Salt Range Fossils. Palaeontol. Indica, 1887. — Naug, E., Ueber sogeuannte Chaetetes ;ms
mesozoischen Ablagerungen (Neues Jahrb. fur Mineral.), 1883, I., p. 171. — Beecher, C. E., The
Development of a Palaeozoic Poriferous Coral. — Symmetrical Cell Development in the Favositidae.
(Trans. Conn. Acad. vol. VIII.), 1891.

TABULATA— FAVOSITIDAK

sometimes tubiform iniir;il JMHVS. Tin1 cnrallites BT6 u-iially polygonal in
contour, and their walls exhibit in t ran>\ crse sections a dark, or sometim.-s
lii^ht coloured median line, with thickenings of itereOpUtftma OD either >id>

FIG. 174.

G If. sp. Devonian ; EitVl. A, Corallum, natural si/.-. B, Gorallites enlarged, two

of them brokrn opni and showing tabulae, ''and /', Trans\ ITS.- and longitudinal suctions sho-.vin;,' spiniform
srptu and mural pon-s(/i). (''and I> al'ti-r Nicholson.)

17(. (/). The family is exclusively Palaeozoic, and plays an important part
in the formation of Silurian, Devonian, and Carboniferous coralline limestone.-.

/'»os//,.s Lam. (fW/fm'Y^/w, Goldf.), (Fig. 174). Corallum massive, more
rarely branching. Corallites prismatic, polygonal,
generally hexagonal. Mural pores distributed at
considerable intervals. Septa very faintly developed,
represented by longitudinal ridges or rows of spines,
or occasionally obsolete. Tabulae numerous. Ordo-
vician to Carboniferous: very abundant in Silurian
and Devonian.

''iiliiinin./Hini, Nidi, (('tifiijiwiii. Bill.) Like the
preceding, but with numerous, short, well marked
septa. Mural pores large, disposed in vertical rows
between the >epta. ( )rdovieiaii.

EmmotuiOy K. and II.; Ordovician to Carboniferous.

A i/rfn/Hn-<i, Nidi. ; ( )rdo\ ician (Trenton). S-yringolites,
Hinde : Silurian (Niagara).

Packypora, Lind. (Ki^. 17.")). Corallum branching, composed of prismatic,
polygonal corallitcs, the walls of which are so thickened towards their mouths
by layers of stereoplasma that the calices appear to have
circular coiit «nrs. Septa very minute ; mural pores
scanty, but often of large size. Abundant in Silurian
and Devonian.

Ti-tii-hi//Mn-ii. ]•".. and H. Dendroid with cylindrical
stems. Corallites polygonal; walls so thickened by lavers
of stereoplasma that the calices become round and great Iv
contracted, and appear to be superficially widely separated.
Mural pores few and irregularly distributed. Septa represented by rows (,i
spines. Tabulae remote. Common in Devonian.

Ki... 17'..

I'r.'cli
; Kit-!. .!. ,

/:. Longitudinal
section, enlarged; i>, Mmal p.m-s

(atVr Nicholson).

Th, 17.'..

Silurian (Niagara); x.-v

York.

100

COELENTERATA— ANTHOZOA

SUB-BRANCH IT

Striatopora, Hall (Fig. 176). Like the preceding, but with tubes contracted
by stereoplasma at a greater depth, so as to give the calices a funnel-shaped
appearance. Silurian and Devonian.

Alveolites, Lam. (Fig. 177). Corallum massive or branching, composed of
small, contiguous, compressed, thin-walled corallites, with obliquely opening
triangular or semilunar calices. Septa very faint, represented merely by ridges

FIG. 177.

A, Alveolites suborbicularis, Lara. Middle Devonian ; Gerolstein, Eit'el.
Natural size. B and C, Alveolites Labecliel, E. and H. Silurian (Wenlock) ;

FIG. 178.

Pleurodictyum problenu i tic urn,
Goldf. Lower Devonian;
Coblenz. Natural size. Vermi-

. , , . . . . -

Ironbridge, England. Tangential and vertical sections, 10/1 (after Nicholson). form foreign body in the centre.

or rows of spinules, sometimes but a single row present. Mural pores of large
size, irregularly distributed. Very common in Silurian and Devonian.

Cladopora, Hall. Coenites, Eichw. Silurian and Devonian.

Pleurodictyum, Goldf. (Fig. 178). Corallum depressed, discoidal, circular,
or elliptical in contour, lower surface covered with concentrically striated

FIG. 179.

Michelinia favosa, do Kon. Carboniferous Limestone ; Toujmay, Belgium. A, Corallum from above.
B, Lower surface with radiciform epithecal processes. C, Vertical section (after Gaudry).

epitheca, and frequently with foreign vermiform body occupying centre of the
base. Corallites small, polygonal, contracted inf eriorly so as to become funnel-
shaped. Septa represented by faint marginal ridges, or obsolete. Walls
pierced by irregularly distributed mural pores. Tabulae scanty. Devonian.
P. p'ollematicum, Goldfuss, is tolerably abundant in the Lower Devonian
" Spirifera sandstone " of the Eifel, but is only known in the form of casts.

si l ;-r|. ASS II

TABULATA— SYRIXGOPORIDAE

101

In these tin- walls of the conillites are represented by narrow fissures which
are bridged across by transverse rods, while the visceral chamber is filled up
with sandstone. /'. .%•////.,/«./-,/. Katon. from the Hamilton Group of North
America, is a closely related species, and also possesses the vermiform body.

Mii-/n-lini<i, do Kon. (Fig. 179). Discoidal or hemispherical coralla, often
of considerable si/.e, and covered on the under surface with concentrically
striated epitheca, which frequently develops hollow radiciform processes.
(,'orallites polygonal, rather large. .Septa represented by numerous longitudinal
striae or ridges; mural pores irregularly distributed: talmlae very numerous,
oblique or curved, incompletely developed, and usually filling the visceral
chamber with loose vesicular tissue. Devonian and Carboniferous. M. fin-n* /,
de Kon., extraordinarily profuse in Carboniferous Limestone of Belgium.

Family 2. Auloporidae. Nich. (Tubulosa, Milne-Edwards and Haime).

Oreepfaff, branching, or reticulated tubular coralla, composed of cylindrical, beaker,
or trumpet-shaped condlites, with thick, imperfoi'ate, wrinkled walls. Septa represented
fry faint marginal striae ; tabular moderately numerous or want-
ing. Reproduction by baml or lateral gemmation. Ordovician
to Carboniferous.

Aulopora, Goldf. (Fig. 180). All the corallites of the
prostrate corallum are attached by the whole of the lower
surface to some foreign object (Alveolites, other corals, or
mollusks). Tabulae more or less curved ; reproduction by
basal gemmation. Ordovician to Carboniferous.

Cladoehontts, M'Coy (Pyrgia, E. and H.) Corallum
1 Handling, attached only at isolated points, and composed
of funnel-shaped corallites without tabulae and septa.
Reproduction by lateral gemmation. Carboniferous.

lloiidngeria, Nich. (Quenstedtia, Rom.) Spreading, semi-
erect, bushy coralla, only basally attached, and with cvlin-

i • i 11 •, • i .L i • mil ojxi »,

ducal corallites increasing by lateral gemmation. Tabulae Goldf. Devonian
moderately numerous, horizontal. Silurian and Devonian.

t«l»«'fnrmi*,

1 " • >sl

stone; RognitatkmtL Fich

telgebirge. Natural si/c.

Family 3. Syringoporidae. Milne-Edwards and Haime.

Fasciculate coralla composed of cylindrical <-<>r<tlHtcs, united
nf ///A/-/W.S along Hie sides by hollow connecting p}-ocesses or by
horizontal expansions. Walls thick, wrinkled; septa faintly
develoji"/, represented by delicate ridges or longitudinal rows
of spinules ; tabulae numerously developed, usually ineyulm-Iy
funnel-shaped. Reproduction by basal gemmation or by buds
arising from the connecting processes and ltnri;<iiit<il expansions.
Ordovician to Carboniferous; maximum in Devonian and
Carboniferous.

Syringopora, Goldf. (Fig. 181). Fasciculate coralla.
often attaining considerable size, and composed of cvlin-
drical, thin-walled, somewhat flexuose corallites ; the latter
communicate by means of hollow, cylindrical, connecting
processes. Septa rudimentary; tabulae funnel-shaped.

102 COELENTERATA— ANTHOZOA SUB-BRANCH n

Corallum commencing with prostrate basal network similar to Aulopora.
Numerous species ranging from Silurian to Carboniferous.

Chonostegites, E. and" H. Corallum massive; cylindrical corallites con-
nected by horizontal, hollow, laminar expansions into which the endothecal

tissues are directly continued ; tabulae oblique, cystoid.

Devonian.

Thecostegites, E. and H. Corallum encrusting ; corallites

short, cylindrical, and connected by thick horizontal plates.

Tabulae approximately horizontal ; septa twelve in number,

represented by marginal ridges. Devonian.

Family 4. Halysitidae. Milne-Edwards and Haime.
Chain corals.

Corallum composed of long, cylindrical, laterally compressed
corallites, which are joined to one another only along the more
constricted edges, and form free, vertical, intersecting, and an-
astomosing laminae. Wall thick, covered on free sides by wrinkled
Liisp<f Silurian' -"oott- epitheca ; tabulae numerous, horizontal^ or concave ; septa repre-
land. Natural size. sented by vertical ridges or rows of spines, in cycles of twelve,

sometimes entirely absent. Increase by stolonal gemmation.

The single genus Halysites, Fischer (Catenipora, Lam.), (Fig. 182), comprises
two groups of species ; those in which the corallum is composed throughout of
corallites of .equal size (H. escharoides, Lam. sp.), and others in which any two
of the larger corallites are separated by the intervention of a single smaller,
closely tabulate tube (H. catenularia, Lin.) Ordovician and Silurian; maximum
in Silurian.

Family 5. Chaetetidae. Milne-Edwards and Haime.

Massive cwalla, composed of fine, subequal, tubiform corallites, contiguous on all
sides. Calices rather irregular in shape, one diameter slightly greater than the other.
Walls thoroughly amalgamated, common to adjacent corallites, imperforate, apparently
composed of closely arranged, ankylosed vertical columns, which terminate at the surface
in hollow prominences. Septa absent, but one or two tooth-like projections often observ-
able in sections. Tabulae horizontal, remote or abundant.

AH the forms belonging to this family are extinct, and occur chiefly in the
Ordovician, Silurian, Devonian, and Carboniferous systems ; but they are also
found sporadically in the Trias, Jurassic, and Cretaceous. They are important
as being largely concerned in the formation of Palaeozoic coral reefs, especially
during the Ordovician. Milne -Ed wards and Haime regarded them as An-
thozoans, Rominger and Lindstrom as Bryozoans ; while Dybowski, though
admitting their resemblance to certain Bryozoans, emphasised their affinities
with the Favositidae. By Nicholson they were assigned to v the Octocoralla, for
the reason that the corallites frequently exhibit a dimorphous character the
same as in Heliolites and Heliopora, besides agreeing in their microscopic
structure with Heliolites ; while in addition they possess well-developed tabulae
and imperforate walls, and increase by intermural gemmation or by fission.
Nevertheless, their resemblance to certain of the cyclostomatous Bryozoans
(Heteropora) is fully recognised by Nicholson, and insisted on by Ulrich.

Chaetetes, Fischer (Figs. 183, 184). Corallites long, thin-walled, prismatic,

BUB-CLASS

TABULATA— CHAETETIDAB

103

polygonal, all of one kind, and multiplying l»y fission. Uncompleted fission of

the tubes often indicated in section by tootlilike projection extelidilli; into
\isrn-al cliaml.er. Walls st nictmvless, without dark median line; tabular
complete, remote. Very abundant in Carbon
ifrrous Limestone; found also in Lias and Cppn-
Jurassic. I '. /W/"/<s, Fisch., is an important
i-ock imildrr in the Russian Carboniferous Lime
•tone, especially iii the vicinity of Moscow.
Pseinln,

Hang; - n

Jurassic.

Quenst. sp.

AIoufi<'nlij'"i''i,
d'Orb. (emend.
Nichj. (Figs.
185-187). Mas-
sive, tuberous,

Flem. Carbon ifer-

<iiis Limestone ; England. .d, Transverse
sect inn parallel to upper surface.
/,', Vertical section, both enlarged ;
p, Projecting spines representing un-
completed fission (after Nicholson).

184.

Chnetetes radians, Fischer. Carbonifer-
ous Limestone ; Moscow, Russia. Portion
of longitudinally fractured corallum,
natural size.

discoidal. ra-
mose, or en-
crusting coralla

of extremely variable form and size, and composed of numerous, fine, tubular
corallites, usually of two series, the walls of which are imperf orate and closely
approximated to one another, but are not amalgamated. Multiplication by
intermural gemmation, more rarely by fission. Tabulae horizontal, and either
complete, extending entirely across the visceral chamber, or incomplete ; in the
latter case the spaces where tabulae are not developed are filled with

(lli-ti'rntr.'/pi') r«l,x..-", K. Mill

H. Onloviciai

(Cincinnati Group); Cincinnati, Ohio.

.1. Ciiialluin, natural sixe. /;, Surface slightly niaunilicd. (', Tangential section, parallel to external surface,
» ^ /», V.-rtiwil section, ---o/i. C'""'! /'after Xicholson.)

cystoid calcareous plates. The walls differ from those of Cfmetetes in that they
are composed of two distinct lamellae separated by a dark or light median line,
and are sometimes thickened by deposits of carbonate of lime. The corallites
are polygonal or round in contour, and, as a rule, two series are distinguishable :
a series of larger tubes with remotely situated tabulae, and another series of more
or less numerous interstitial tubes, which are smaller and more closely tabulate
than the former. The larger tubes (autopores) are often surrounded on all sides

104

COELENTERATA— ANTHOZOA

SUB-BRANCH II

by the smaller (mesopores), and hence are completely separated from one another.
Occasionally, in addition to the preceding, a further series of tubes called
(icanthopores occur, which are thick -walled and form small tubercles on the
surface. Extraordinarily abundant in Ordovician and Silurian, particularly the
former ; rarer in Devonian and Triassic.

Nicholson compares the mesopores of Monticulipora with the siphonopores
of Heliopora, and supposes the corallum to have been inhabited by dimorphous

FIG. 186.

Enlarged tangential sections parallel to
external surface. A, Monticulipora (Hetero-
trypa)pukhella, E. and H. B, M. (Heterotrypa)
ramosa, E. and H. (after Nicholson).

FIG. 187.

Monticulipora (Diplotrypa) Petro-
politana, Panel. Ordovician ; St. Peters-
burg. Enlarged tangential section
parallel to external surface (after
Dy bow.sk i).

polyps. F. Eoemer holds the smaller tubes for immature corallites formed by
budding. The following sub-genera are recognised by Nicholson : —

a. Heterotrypa, Nich. (Figs. 185, 186). Corallites of two kinds, the larger-
ones sub-polygonal, and separated by a single row of mesopores. Walls

FIG. 188.

Prasopora Selwynii, Nich. Ordovician ;
Ontario. A, Tangential section parallel to ex-
terior. B, Vertical section, enlarged. C, Auto-
pores ; t, Tabulae; t', Cystoid tabulae (after
Nicholson).

FIG. 189.

Neuropora angulosa, Goldf. sp. Upper Jur-
assic; Oerlingen, near Ulm. A, Portion of ex-
ternal surface enlarged. B, Corallum, natural
size.

thickened towards mouths of tubes ; tabulae horizontal ; acanthopores generally
present.

b. Monotrypa, Nich. Corallites all similar, or of two kinds, not conspicuously
different in size, and usually polygonal and thin -walled. Ordovician to
Devonian, also Triassic. M. Itecubariensis, Schaur. sp.

c. Diplotrypa, Nich. (Dianulites, Eich.), (Fig. 187). Corallites of two kinds,
uniformly thin-walled ; the autopores aggregated into clusters or monticules,
but also scattered with the mesopores throughout the colony. Ordovician.

d. Prasopora, Nich. (Fig. 188). Corallites of two kinds, uniformly thin-
walled ; mesopores with numerous horizontal tabulae, autopores with incomplete
and cystoid tabulae. Ordovician and Devonian.

e. Peronopora, Nich. Like the preceding, but thick-walled.

srn-ci,Ass in TABULATA— OOTOCORALLA 105

titenopora, Lonsd. 1 branching or lobate coralla composed of fine tubular
coi-allitcs radiating outwards and becoming reflexed. Walls thickened by
annular deposits of stereoplasma ; tabulae scanty. Abundant in Carboniferous
and /echstein.

Geinitzella, Waag. and Wentz. Like the preceding, but with walls only*
slightly thickened. Carboniferous to Zechstein.

? Neuropora, Bronn. (Chri/saora, Lamx.), (Fig. 189). Ramose or tuberous
coralla, composed of long, polygonal tubes, nearly uniform in size, and with
mouths separated into groups by elevated, non - tubular ridges ; tabulae
numerous. Jurassic and Cretaceous.

Family 6. Fistuliporidae. Waagen and Wentzel. ^/? '!?'**

Encrusting, massive, or branching coralla, composed of two series of fine tubiform
corallites. Walls compact ; tabulae Iwrizontcil ; septa wanting. Autopores multiply-
ing by coenenchymal gemmation, mesopores by fission. Silurian to Zechstein.

The Fistuliporidae resemble the Helioporidae in a number of particulars,
especially as regards the coenenchymal gemmation of the autopores. Waagen
assigns them to the vicinity of the Helioporidae, while Nicholson regards them
as a sub-family of the Monticuliporidae.

Fistulipora, M'Coy. Corallum composed of two series of tubiform corallites ;
autopores round or sub-triangular in contour, and embedded in a coenenchyma
constituted of the smaller mesopores. The latter are much more closely
tabulate than the autopores, and give the coenenchyma a vesicular, multicellular
appearance. Walls of the autopores are thickened on one side, and- frequently
provided with two septa-like processes. Common in Devonian, Carboniferous,
and Permian.

Callopora, Hall ; Prasopora, Nich. Ordovician and Silurian. Labechia, E.
and H., occurring in the Ordovician and Silurian, probably also belongs here.

Geological Range of the Tabulata.

With but few exceptions, the Tabulata are restricted to the Palaeozoic
formations, and from the Ordovician to the Carboniferous periods inclusive are
prominently concerned along with the Tetracoralla and Hydrozoa (Stromotoporidae)
in the building of coral reefs. Of the six families composing the Tabulata, the
Halysitidae alone are confined to the Silurian ; the rest are all more or less
plentiful from the Ordovician to the Carboniferous; while the Fistulip<>r'nl«i-
persist as late as the Zechstein, and the Chaetetidae range from the Ordovician
to the Cretaceous.

Sub-Class 3. OCTOCORALLA. Haeckel.

(Octadinia, Ehrenberg; Alcyonaria, Milne-Edwards.)

Composite colonies, rarely simple polyps, the individuals provided with eight
mesenterial folds and eight broad, pinnately fringed, or plumose tentacles, which form
a single cycle about the mouth.

Hard skeletal elements are very generally developed in the Octocoi'alla, being
absent in comparatively few forms, and are remarkable for their manifold

106

COELENTERATA— CNIDARIA

SUB- BRANCH II

variety ; they occur either detached in the ectoderm and mesoderm, or are
closely packed together at the base to form a horny or calcareous axis (sclero-
basis), about which the polyps are distributed. Sometimes the calcareous
bodies (sclerodermites) form compact tubes which are periodically
partitioned off' into storeys with the upward growth of the
animal. Reproduction is accomplished either sexually or
asexually by basal or lateral gemmation, rarely by fission.

Only the calcareous parts are known in the fossil state, such
as the solid axes, detached skeletal elements, tubes, and com-
posite coralla ; the horny structures are totally destroyed during
fossilisation. The Octocoralla make their appearance in the
Ordovician, but belong only exceptionally to the more common
fossils.

I

Family 1. Alcyonidae. Milne-Edwards and Haime.

Fixed, fleshy, lobate, or ramose polyp stocks (very rarely simple
individuals), with echinulate or spicidar calcareous bodies (sclero-
dermites) occurring detached in the soft parts.

Isolated sclerodermites readily escape observation, owing to
their minute size and fragile constitution. They have been
detected as yet only by Pocta l in the Upper Cretaceous strata
near Laun, Bohemia.

Family 2. Pennatulidae. Milne-Edwards and Haime.

Polyp stocks with base embedded in sand or mud, and with horny
or calcareous sclerobase ; polyps dimorphic.

Slender, round, or quadrate calcareous axes referable to the
Pennatulidae have been detected with certainty only in the Trias
(Prographularia, Freeh.), Cretaceous (Pavonaria, Cuv. ; Pennatulites
and Palaeosceptron, Cocchi ; Glyptosceptron, Bohm), and Tertiary
(Graphularia, E. and H.), (Fig. 190).

Family 3. G-orgonidae. Milne-Edwards and Haime.

Fixed, branching, or fan-shaped colonies, with horny or calcareous
(Eocene) !imeFa°rS solid sclerobase, or with jointed axis composed of alternating hoi-ny
and calcareous segments.

FIG. 19t.

Graphularia dcser-
torum, Zitt. Nuin-

freh, Libyan
Desert, a, Axis,
natural size ; b, V ,
Cross - sections ; c,
Striated surface,
enlarged.

All the genera possessing horny, flexible axes (Goi'gonia,
Pihipidogorgio, etc.) are perishable. Detached remains referable
to Primnoa, Gorgonella, and Virgularw, the axes of which are
composed of both horny and calcareous layers, have been described from the
Tertiary. In the genus Isis the axis consists of cylindrical, calcareous segments
alternating with horny connecting joints. It is found fossil in the Tertiary,
and has been reported also from the Cretaceous. The genus Moltkia, occurring
in the Upper Cretaceous, has cylindrical joints which are pitted with slight
depressions indicating the position of branches. In the red or gem coral
(Gwallium, Lin.) the axis is built up of spiniform sclerites, which are united

1 Pocta, PhilqU'- Sitzungsl.ericlite der Wiener Akatl. der Wisseiisch., Bd. 92, Jalirg. 1885.

SUB-CLASS III

A N T I fOZOA— OCTOCORALLA

107

l»v ;i tibro-crystalliiH' calcareous matrix impregnated with organic matter. It
is found hut rarely in tin- fos>il state, hut is known from the ( Yetaceous and
Tertiar.

Family 4. Tubiporidae. MiliK--l'Mwanl< ami

»•/' red-coloured /«//•/»//»•/ calcar&nu tofas conntctrf by

plot

The cylindrical tubes of the remit Or^anpipe Coral (7?///;//w//v/) are com
posed of spiniform sck-rites, which are united with one another directly in sueli
nianner as to enclose small hollow spaces appearing superficially as pores. The
connecting horizontal plates or floors a re traversed by canals which communicate
with tin- \ isreral diamliers of the tubes by means of numerous round openings ;
ne\\ coi-allites are luidded from their upper surfaces. Unknown in fossil state.

Family 5. Helioporidae. Moseley.

of two series of tubifonn condlites ; the larger tubes
are embedded in a strongly developed coenenchyma nmde up of *.•/>/"//<•/•
(siphonopores). Both autopores and siphonopores are closely tabulate; the
are provided with ridge-like pseudosepta, which, however, do not n>m>*pinnl
numerically with the tentacle.

The affinities of the Helioporidnc with the Octocoralla were first pointed out
by Moseley.1 The larger polyps inhabit the autopores, and are furnished with
eight mesenterial folds and a crown of eight tentacles ; while the smaller
polyps, which are without either A J: c

tentacles or sexual organs, are
lodged in the siphonopores. The
skeleton is composed of cal-
careous trabeculae, the same as
in the ]Ic.i-in-nrnll(i, from whose
centres of calcification radial
fibres extend outwards in caespi-
tose fashion. The siphonopores
multiply by intermural gemma
tion, while the autopores are
formed by the coalescence and
fusion of a number of the siphono-
pores.

Heli»/»>rn, niainv. (Fig. 191, A, B). Corallum massive or ramose ; autopores
with 12-25 slightly developed pseudosepta, and embedded in a coenenchyma
made up of smaller siphonopores; the latter are more closely tabulate than the
autopores. Cretaceous to Recent.

Polytremanx, d'Orb. (Fig. 191, (.'). Like Helioporv, but pseudosepta much
more strongly developed, sometimes reaching nearly to the centre. Cretaceous.

Certain Palaeozoic corals (Heliolitidne} exhibiting characters very similar to
IHlniHH-ii are assigned to the same vicinity with the latter by Moseley,
Nicholson, and other authors. Like Heliopoi'a, the corallum in these forms i-
massive, and consists of larger tubes embedded in a coenenchyma formed of

Fro.

Rcuss sp.

101.
Upper Cretaceous

St.

Beuw. Upper Crateceoiu

sectiou> enlarged<

Oown, saizkiumncr-ut. Vertical

1 Moseley, If. A"., Philosophical Transactions, Royal Society, vol. 166, 1877.

108

( ,'OELENTERATA— CNIDARI A

CLASS II

smaller tubes. Both series of corallites are provided with numerous horizontal
tabulae ; and, as in Heliopora, the autopores are produced by the coalescence of
a number of adjoining coenenchymal tubes. In the Heliolitidae, however,
twelve well-developed septa are uniformly present. The walls of the corallites
are composed of homogeneous, compact, calcareous matter, and exhibit the

Hdiolites porosa, Goldfuss. Devonian ; Eifel. A, Corallum, natural size. B, Portion of outer surface
enlarged. C, Longitudinal section, enlarged.

histological structure as the. Favositidae and Chaetetidae. Owing to these
anomalies the systematic position of the Heliolitidae remains uncertain.

Heliolites, Dana (Fig. 192). Corallum massive, nodular, or ramose. Auto-
pores with twelve more or less strongly developed pseudosepta, though'
occasionally represented by rows of spinules, and frequently with central
columella. Siphonopores without septa, and multiplying by fission or inter-
mural gemmation. Abundant from Ordovician to Devonian.

Plasmopora, E. and H. Like Heliolites, but having walls of the siphonopores
incomplete, and tabulae of contiguous tubes fused together so as to form a
vesicular tissue. Ordovician to Devonian.

Class 2. HYDROZOA. Huxley. Hyclroids and Medusae.1

Sessile or free-swimming polyps or polyp stocks, without oesophageal tube, and with
simple gastrovascular cavity not divided into radial pouches.

The Hydrozoans are organisms which rarely secrete hard parts, and hence
are ill-adapted for preservation in the fossil state. The ramifying polyp stocks
are usually inferior in size to those of the Anthozoa, and possess always a
simpler structure ; dimorphism or polymorphism is, however, exhibited by the
different individuals, some of which perform solely vegetative, and others only
locomotive functions. Of great interest is the prevailing alternation of genera-
tions, in which process fixed polyp stocks give rise to a generation of free-
swimming Medusae, the eggs of which develop in turn into polyps.

The Hydrozoa are all aquatic, and with few exceptions are inhabitants of
the sea. They are commonly divided into the two following sub -classes : —
Hydromedusae and Acalephae.

1 Huxley, T. N., The Oceanic Hydrozoa. London, 1859. — Agassiz, A., North American Aca-
lephae (111. Cat. Museum Comp. Zool. Cambridge, II.), 1865. — Hincks, T., Natural History of the
British Hydroid Zoophytes, London, 1868.- — -Glaus, C., Untersuchungen iiber die Organisation, etc.,
der Medusen. Leipzic, 1883. Cf. also references on pp. 109, 114, and 121.

SUM 'I. ASS I

HYDROZOA— HYDRO*! KI >rs.\ K

109

Sub-Class 1. HYDROMEDUSAE. Vogt.1

Sessile or free-.w'im nnn<i, ux/ml/i/ branching r///o//?'rx, //-///t dimorpkici /«////•////>-, "//</
jmli/ji* : tin1 In tier frequently become liberated in the form of small, free-
xirimnting ifedhtsat, ?/•//// non-lobate umbrellas composed of a hyaline, gelatinous

Six orders of ////<//•»///"///.<//,• ;iro recognised — 7///'//v//-/>^, Hydrotor&llinae,
Tnbulnri<n; CampamUariae, Trachymedtuae, and Siplwnophorae. But of these only
the HydrocurnlHiiiH'. Tnbnl<iriin>, and Campanulariae secrete durable, calcareous, or
chitinous structures.

Order 2. HYDROCORALLINAB. Moseley. *

Xiihnl i/olyps secreting at the base a dense calcareous skeleton, traversed at intervals
ifo series of vertical tubes, into which the dimorphic zooids can be retracted.

The Hydrocorallinae comprise the two recent groups Milleporidae and Stjilnx-
which were universally regarded as true corals until Louis Agassi/ and
Moseley proved their relationship to the Hydrozoa.

Millepora, Lin. (Fig. 193). Massive, foliately expanded, encrusting, or
^branching polyparia (coenosteum), often attaining considerable size. Upper
sin face punctured by round open-
ings of the larger tubes (gastro-
pwes), between which are the
mouths of numerous smaller
tubes (dactylopores). The skeleton
i- composed of a network of
juiastomosing calcareous fibres,
traversed by a system of tortuous
canals. The gastropores lodge
the larger, nutritive polyps, and
the dactylopores the smaller, food-
procuring zooids ; the latter have
no mouth, but are provided with
short, clavatc tentacles on their

, . .

sides, and their tubes commum-

-.1 +V>« rv,4^v,, 1

CatC With the Vermiform CanalS.

Zooidal tubes tabulate, but non-
sept ate. The genus is an important reef -builder of the present day, but occurs
only sparsely in the fossil state. Earliest known forms appear in the Eocene.

As'///A/.s/6'/-, Gray. Branching polyparia composed of a network of fibrous,
rose-coloured coenenchyma, in which are situated calicular depressions that are

1 . 1 II ni,i, t, ./. (,'., Monograph of the Gymuoblastic or Tubularian Hydroids ; Ray Society, 1371-72.
S!, imixnm, (/., Ueber fos-sile Hydrozoen au.s der Faniilie der Coryniden (Palaeontographica, Bd.
XXV.), 1877. — Ueber triasische Hydrozoen vom ostlicheii Balkan (Sitzungsl)er. Wiener Akad.
in.it li. phys. Classc, Bd. CII.), 1893. — Canavari, M., Idrozoi Titoniani appartenanti alia Fainiglia
delle Ellipsactinidi (Mem. Comitato Geol. vol. IV.), 1893. — Nichol^m. II. A., Monograph of the
British Stromatoporoids (Palaeontographical Society), 1886-92. — Bargatzki, A., Die Stromatoporen
iU-s rlicinischfii Devons. Bonn, 1881.

/, 11. .\'., Philosophical Transactions Royal Society, vol. 167, 1878.

FIG. 193.

Millepora nnilosa, Esp. Recent. A, Upper surface of coeno-
steuin, showing gastropores, /,-, and daetyloi>ores, c, •*<>/! . /;, Ver-
tical sect inn, /., ^astropores with tabulae, t ; c, Vermiform canals
coiimiunicatiny with dactylopores, so/j (after Steinmann).

110

COELENTERATA— CNIDARIA

CLASS II

provided with pseudosepta and columellae, and communicate with the zooid
tubes and vermiform canals. Recent, and occurring sparsely in the Tertiary.

Order 3. TUBULARIAE. Airman.

Polyp stocks which are either naked or covered with chitinous outer layer (periderm).

Both the polypoid nutritive zooids, and also the medusoid reproductive animals are

without cup-shaped hydrothecae surrounding the polyp head. A chitinous or calcareous

skeleton (hydrophyton) is frequently secreted at the base.

Hydractinia, v. Bened. (Fig. 194). Hydrophyton in the form of encrusting,

chitinous, rarely calcareous expansion, frequently investing gastropod shells.

The crust consists of
successive, slightly sepa-
rated, horizontal laminae,
which are supported by-
numerous vertical rods
or columns (radial
pillars). The surface is
covered with projecting
hollow spines and tuber-
cles, and is also traversed
by shallow, branching
grooves (astrorhizae). In-
terlaminar spaces com-
municating with the sur-
face by means of rounded
tubes. Tertiary and
Recent.

Ellipsactinia, Steinm.
Hydrophyton irregu-
larly ellipsoidal, com-

FIG. 194.

A, Hydractinia echiwato, Flem. Recent ; North Sea. Portion of parasitic
colony, greatly enlarged ; hy, Polyps (hydranths) ; go, Generative buds
(gonophores) ; hph, Hydrophyton adherent to shell of Buccinium undatum,
and showing reticulated structure in vertical section. B, Hydractinia
calcarea, Cart. Vertical section of hydrophyton, greatly enlarged (after
Carter) ; a, Primary basal lamella ; b, Interlaminar space ; c, Second
lamella ; d, Radial pillars between the lamellae ; e, f, Tubercles and spines posed of thick, COnCCn-
prqjecting on upper surface. C, Hydractinia pliocaena, Allm. Pliocene; ~_ . •,. •, -.
Asti, Italy. Hydrophyton encrusting on Nassa shell (natural size). triC, Slightly Separated,
D, Portion of magnified surface of the latter, showing branching grooves «a 1«Q T.Qrtlia Inrnolla^

and wart-iike tubercles. calcareous lamellae,

wThich are united by

sparsely distributed vertical columns. Lamellae are formed by the anastomosis
of exceedingly delicate calcareous fibres, punctured by numerous fine radial
tubes, and furnished on both sides with pits, tubercles, and branching furrows.
Upper Jurassic (Tithonian) ; Alps, Carpathians, and Apennines.

Sphaeractinia, Steinm. Like the preceding, but composed of thin, widely
separated lamellae, which are supported by numerous radial pillars. Centre
frequently occupied by a foreign body. Upper Jurassic (Tithonian).

? Loftusia, Brady (Fig. 195). Ellipsoidal or fusiform bodies, composed of
thin, concentric, or spirally rolled calcareous lamellae. Interlaminar spaces
wide, intersected by numerous radial pillars, and often secondarily filled with
calcareous mud. Eocene ; Persia.

Parkeria, Carp. Globular or walnut- shaped organisms with nodulated
exterior, and composed of rather thick, concentric, calcareous lamellae. Inter-
laminar spaces divided into chamberlets by stout radial' pillars, which usually

BUB-CLASS I

1 1 V I mOZOA— TUBULARIAE

111

extend continuously through ;i number «.f lamellae. Both lamellae and pillars^
consist «.f i.iii.utcly tabulated tissue, the tubules of which are radial in arrange-
,,,,-nt. Centre fluently occupied by .-i foivign body. Cambridge Greensand
(Cenomanian).

Tin- genera Parteria and h,ftn*i" \v«'iv originally described as agglutinate.
Foraminifera : but they are manifestly very closely allied to Ellipsadinia and
Sphaeractinia,

Powphacra, Steimn. (Fig. 196). Globular masses of the size of peas or
ha/el nuts, t're<|uently growing around some foreign body, and composed of
anastomosing calcareous fibres which are penetrated by
numerous radial tubules : the latter open on the surface in the
form of lar^e pores, around which radial or stellate furrows
(,i*tmrl,i\i>i } are sometimes grouped. Upper Cretaceous.

FIG. 195.

l.i'ftusiii Pentad, Brady. Eocene; Persia. A, Specimen cut open to show general
structure, natural size (after Brady). li, Section showing two lamellae and inter-
liiininar lillinj:, greatly enlarged.

FIG. 196.

Porosphaera gldbu-
l«rix, Phill. sp. Upper
Cretaceous ; Riigen.
.4, Skeleton, natural
size ; I, Cavity origin-
ally occupied by
foreign body. B, Trans-
verse section showing
radial tubes of gastro-
pores, '-/! (after Stein-
inann).

Stolic.ihiri<i, Duncan. Trias ; Karakoram and Balkan Mountains.

Hdernetridium, Reuss. (Syringosphaeria, Duncan). Spheroidal, nodular
bodies of considerable size, composed of slender, anastomosing, and more or
less distinctly radial calcareous fibres. Skeleton comparatively dense, but
perforated by two series of zooidal tubes appearing superficially as pores. The
apertures of the larger tubes are round, those of the smaller stellate, and are
surrounded by radial furrows. Alpine Trias.

Appendix to the Hydrocorallinae and Tubulariae.
Stromatoporoidea. Nicholson and Murie. }(

Closely allied to the HydrocoralUnae and Hydractinia are the extinct Stromato-
/><ii-ii/</('<i, \vhich combine in many respects the characters pertaining to both of
the above-named groups, but whose" exact position in the zoological system
n 'mains as yet uncertain. During the Palaeozoic era, to which they are con-
fined, the Stromatoporoids were important geological agents, whole beds of
limestone being often essentially constituted of their remains. In the Mesozoic
era they are replaced by very closely allied forms of HydractinM, which in all
probability represent their immediate descendants.

The Stromatoporoids secrete hemispherical, globular, nodular, or horizontally
expanded skeletons, which are sometimes encrusting, sometimes attached by a
short basal peduncle, and are covered on the under side with concentrically

112

COELENTERATA— CNIDAEIA

CLASS II

wrinkled epitheca, while the apertures for the emission of the polyps are
situated on the upper surface. The general tissue of the coenosteum is com-
posed of numerous, concentric, undulating, calcareous layers or laminae, which
are separated by narrower or wider interlaminar spaces, but are at the same
time connected by numerous vertical rods (radial pillars). The pillars as well
as the laminae are traversed, as a rule, by minute, irregularly directed canaliculi.
In some genera the coenosteum is provided with vertical tabulate tubes,
which most probably served for the reception of the polyps, as in the genus
Millqwra ; but in many instances they are wanting. The surfaces of the
laminae typically exhibit pores and small tubercles, and frequently also shallow
stellate furrows (astrorhizae), which radiate outwards from numerous centres.
Sometimes the laminae consist merely of a loose network of horizontal calcareous
fibres.

Goldfuss at first held the Stromatoporoids occurring so profusely in the
Eifel for corals (Millepora), and subsequently for sponge-like zoophytes ; while

von Rosen considered
them as horny sponges
that had become
secondarily calcified.
Sandberger and F.
Roemer assigned them
to the Bryozoans;
Dawson to the Foram-
inifera ; Sollas to the
silicious sponges (Hexac-
tinellida) ; and Salter to
the calcareous sponges,

Fid. 197.
Actinostroma intertextuin, Nich. Silurian (Wenlock) ; Shropshire. A, Tan-

gential section showing radial pillars and reticulated structure of concentric whoSO example Nichol-
laminae. B, Vertical section, showing formation of laminae out of processes 0 rv „ 0 1 ^ ^ •Pf-Jl^-nrQ^
given off horizontally by radial pillars, 12/1 (after Nicholson).

Lindstrom, Carter, and

Steinmann subsequently pointed out their relations to Hydradinia and Mille-
pora ; and Nicholson and Murie now regard them as constituting an independent
group of extinct Hydrozoans allied to Hydradinia on the one hand (Adinostro-
midae), and Milkpora on the other (Stromatoporidae and Idiostromidae).

Adinostroma, Nich. (Fig. 197). Skeleton having vertical or radial pillars
disposed at tolerably regular intervals, and extending continuously through all
or at least a considerable number of laminae ; in vertical sections, accordingly,
exhibiting a quadrate meshwork. The laminae consist of an anastomosing
network of calcareous fibres, generally having a porous structure ; their surfaces
are covered with projecting granules or tubercles, which represent the free
upper ends of the vertical pillars. Rare in Silurian, but very abundant in
Devonian of the Eifel, England, and North America. A. dathratum, Nich.
( = Stromatopora concentrica, pp., Goldf.)

Clathrodidyon, Nich. Like the preceding, but with radial pillars extending
only between the upper and lower surfaces of successive laminae. Characteristic
of Silurian ; rare in Devonian.

Stromatopora, Goldf. emend. Nich. (Pachystroma, Nich. and Murie), (Fig.
198). Radial pillars uniting with the thick concentric strata or latilaminae to
form a finely reticulated tissue, in which tabulate zooidal tubes are sparsely
distributed. Plentiful in Devonian : less common in Silurian.

8UBH

• HYDEOZOA— CAMPANULABIAE

i. Lonsd. (Fig. I'.*'.*), and /'/'"/"//v, IJargat., arc St romatoporoids
which are indistinguishable t'r«.in other species except by the presence of
numerous definitely walled tubes penetrating the coenosteum at closer or

:iiii<ti>iiiii-n lulu i-i'ii!«tii, Nidi, Di vonian
(Cornit'.Tous limestone); Jams, Ontario.
Natural si/e (after Nicholson).

Km. 1 '."'.'.

Caunopora /i/c<r//^i, Phill. Devonian; Torquay,
Devonshire. .-I, Tangential section, natural size.
/;, The same, highly magnified ; a, Vertical " Cauno-
1« ira tube"; //, Canal partially cut into; c, Calcar-
eous fibres traversed by delicate ramifying canalk-uli.
<', Vertical section, highly magnified.

remoter intervals. The tubes are often thick -walled, are furnished with
horizontal or funnel-shaped tabulae, and occasionally with septal spines ; in
many cases they evidently represent the corallites of Aulopora and Syringopora
colonies, which have become enveloped, but have continued to live commensally
within the tissues of the Stromatoporoid. In other
. however, the tubes appear to have been formed
by true Stromatoporoid polyps. Devonian.

Hermatosfroma, Nich. (Fig. 200). Massive or
foliaceous skeletons, composed of thick parallel lati-
laminae, connected by vertical pillars ; pillars often
running continuously through several concentric
laminae. Both pillars and laminae exhibit a dark
median line when viewed in cross-section, indicating
either the presence of axial canals or composition
out of two lamellae. Devonian. lamin:i «<"»i>osed of two slightly

... . ... . „ T -i • i separated lamellae ;», Intel-laminar

Idwstroma, Winch. Coenosteum cylindrical or chambexiet ; c, Badfci puiar tm-

fasciculate, traversed by axial, tabulate zooidal tubes, v

which give off secondary lateral tubes. General tissue reticulated, similar to

Xfruiinifojiorri. \ )e\ onian.

Stylodictyon^ Stromatdporella, and Syringostroma, Nich.; Amphipont, Schulze ;
^fiirlit/Htlcx, Bargat. Devonian of Europe and North America.

A number of genera are described by Waagen and Wentzel from the
Permo-Carboniferous rocks of Farther India, such as Carteriiw, Di.*jcct»jM>ri',
( 'im>jn»-nt etc.

I-'HJ. 200.

Order 4. CAMPANULARIAE. Allman.
(Leptomediisae, CalyptoUastea, Allman ; Thecuphora, Hincks.)

-, In-" in-/t in ;r, i>lmd-like, sessile colonies, with chitinous periderm
tin' /y^.sr, pt'iliittr/i; mill u/m, Um cup-Hh receptacles (liydrothecae) which enclose the

VOL. I I

114

COELENTERATA— CNIDARIA

CLASS II

individual polyps. The proliferous zooids are developed within urn-shaped capsules
(gonothecae) of comparatively large size, and sometimes become separated off us
free-swimming velate Medusae.

Although existing Campanularians (Sertularidae, Plumularidae, Campanu-
Jaridae) are provided with a durable periderm, their remains have not as yet
been detected in the fossil state, with the exception of a few forms from the
Pleistocene. Nevertheless, in the Upper Cambrian, Ordovician, Silurian, and

occasionally in the Devonian, numerous
finely branching plant -like remains are
found, which are sometimes furnished with
a strong foot-stalk, and sometimes terminate
acutely at the base ; the original substance
of which was undoubtedly chitinous. These
forms are grouped together under the
common term Cladophora, Hopkinson, and
may be regarded as- early types of the Cam-
panulariae. Particularly well - preserved
specimens exhibit on one or occasionally on
both sides of the branchlets small cellules
or hydrothecae, which evidently served for
the reception of zooids. Very often the
branches are united by numerous slender
transverse processes or dissepiments.

In the genera Dendrograptus, Callograptus,
Thamnogmptus, and Inocaulis, Hall ; Calypto-
. Hal1- Silurian qraptus. Spencer ; Brwqraptus. Lapworth,

(Niagara) ; Lockport, New York. Natural size. y * ' y y ^ ' " .

b, Dictyo-nema, sp. Branch-bearing hydrothecae. etc., the Organisms are provided With a

>• thick foot-stalk, by which they were prob-
ably attached to some foreign object. The branches are numerous, slender,
often bifurcating, bear hydrothecae, and are connected by transverse processes.
Dictyonema, Hall (Dictyograptus, Hopkin.), (Fig. 201). Funnel- or fan-sTiaped
branching fronds terminating acutely .at the base, and probably unattached.
Branches united at short intervals by dissepiments, and furnished distally on
one side with hydrothecae ; the latter, however, are rarely well preserved.
Ordovician to . Devonian. Particularly common in Ordovician rocks near
Christiania, Norway, but usually compressed into fan-like networks.

Appendix to the Campanulariae.

Graptolitoidea, Lapworth (Bhabdopkora, Allman).1

Under the term Graptolitoidea or Graptolites are included organisms which
are generally found accompanying the Cladophora in Palaeozoic strata, and

1 Barrande, J., Graptolites de Bohenie. Prague, 1850. — Geinitz, 11. B., Die Versteinerungen
der Grauwackenformation in Sachsen. Leipsic, 1852. — Die Graptolithen des mineral ogischen
Museums in Dresden, 1890. — Hall, «/"., Graptolites of the Quebec. Group. Canadian Organic Remains,
Decade II. (Geol. Surv. Canada), 1865.— Herrmann, 0., Die Graptolithen-Familie Dichograptidae,
1885.— Holm, G., Gotlands Graptoliter (Bihang Svenska Vetensk. Ak. Handl. vol. XVI.), 1890.—
On Didymograptus, Tetragraptus, etc. (Geol. Fdren. Stockholm Forhandl. XVII.), 1895.— Lapworth,
C., Notes on the British Graptolites (Geol. Mag. vols. X. and XIII.), 1873-76. Also various papers

SUM-CLASS i HYDKOZOA— < :KA 1TOLITOIDEA 115

which haw Wen considered l.y various authors as plant iv ma ins, horny sponges,
Pennatulidae, (Vphalopods. and Bryozoans. Portlock, in is i:;, first pointed out
their analogy witli the Scrtularians and Plumularians ; and liis inferences as to
their common relationship were gradually corroborated by the painstaking
researches of Allmaii. Hall, llopkinson, Lapworth, Nicholson, and others. The
Uraptolites ditl'er. however, from all existing HydromeduSM, and also from the
closely related ('/mlnjilmrti, in the fact of their non-attachment, and in that a
rod-like axis is almost invariably developed in the periderm.

Graptolites are generally found in an imperfect state of preservation, lying
flattened in the same plane upon the slaty laminae in which they are embedded,
and associated in large numbers. More rarely they occur in limestone, when
the internal cavities are filled with calcareous matter, and the original form
accurately preserved.

The general skeletal tissue (periderm) was obviously flexible, and composed of
>mooth or finely striated chitine ; usually it has the form of a dense continuous
membrane, but in the Retiolitidae it is attenuated and supported by a latticed
network of chitinous threads. It is usually preserved as a thin bitumino-
carbonaeeous film, which, however, is often infiltrated with pyrites, and is not
intVeijui'iitly replaced by a 'glistening greenish-white silicate (Giimbelite).

The organism or hydrosoma of the Graptolites is usually linear, more rarely
jictaloid in form, undivided or branching, and is either straight, bent, or in
exceptional instances spirally enrolled. Cup-shaped hydrothecae, which are
usually obliquely set and more or less overlapping, are borne on on,e or on
both sides of the polypary, and are united by a common coenosarcal canal
enclosed in the periderm. The polypary is strengthened by a peculiar chitinous*
axis (rir'iii/ii, solid axis), which in the monoprionidian forms runs in a groove
lying outside the coenosark on the dorsal side of the organism (i.e. on the side
opposite to the polypiferous margin). But in the biserial Graptolites the
virgula is generally double, and the two halves are either enclosed between the
laminae of a central or sub-central septum, which is formed by the coalescence
of the flattened dorsal walls (Diprionidae) • or they are placed on opposite sides
of the coenosark, and are united with the peridermal network (Rdiolitidae).
Very commonly the virgula projects at'one or at both extremities, but notably
at the distal end of the polypary, as a longer or shorter naked filament; its
proximal extension is often called the radicle.

Springing from the common canal, which runs parallel witn the virgula, is
a series of hydrothecae (th<'i-<n; c<'llules, denticles), which are disposed in longi-
tudinal rows along either one (Fig. 202), two (Fig. 203), or four sides of the
polypary. They usually have the form of elongated, cylindrical, rectangular, or
conical sacs ; their walls are in most cases applied to those of their neighbours
abo\e and below, although occasionally they spring out quite isolated from
one another. Kach hydrotheca opens directly into the common canal, and is
furnished distally with an- external aperture, the form and size of which vary

in Quart. .Fc.inn. CJeol. Soc., 1875, 1878, 1881, and in Annals and Mag. Nat, Hist. 1879, 1880.—
Xi,-hnl*u,,, 11. .!., Monograph of the British (Jraptolitidai-, 1872.— ]',;•„.•,-, ./., Etudes sur les Grap-
I"li1rs dt- Bohrme, 1894. — Richter, Jl., Thiinn^ische (Jraptolithrn (Zritsrhr. dciitscli. ^i-ol. (u-srllsch.),
lid. V.. is:,:; : A VI 1 1., 18(56 : and XXIII., lS71.—Scharenbenj, W., Uel.cr Graptolithen. Bn-shm,
1851. SUM, A'.. [Jebet btihmiache (Ji-aptnlitht-ii (Haitlii.^-r's Natunv. Al.liandl. Bd. IV. AUtli.
I.), 1851.—Tomquisf, S. £., Ol.s.-rviition.s on Graptolites (Acta Univ. Lund. XXVI.. XXVIII..
XXIX.), 1890-92.— Wiman, 0., Ueber Monograptus und Diplograptidae (Bull. Geol. lust. Up.su la.
I.), 1893. [Translated in Journ. Geol. vol. II. p. 267, 1893.]

116

COELENTERATA— CXIDARIA

CLASS ir

extremely in different species. In some forms it is circular or quadrate, and
upwardly directed ; in others it is contracted and opens inferiorly, when the
hydrothecae are bent downwards. Not infrequently the lower lip is orna-
mented with one or two slender spines, which often subdivide arid inosculate
with one another.

The polypary in most Graptolites is furnished at its proximal end with a
minute, triangular, or dagger-shaped body called the sicula (Fig. 204), which
represents the original embryonic skeleton. The first stage of development
consists in the formation of an axis or virgula along the entire length of the
sicula, which axis often projects freely at one or both extremities of the latter.
Hydrothecae are then budded either uniserially along one side, originating from

A, 0, Monograptus i>r!nilini,
Bronn. sp. Silurian (Etage
E) ; Prague. A, Hydrosoma,
natural size. 11, Longitu-
dinal section, enlarged. C,
Dorsal aspect, enlarged.
1), MniHiiir<ii>tu.s Bohemians,
Barr. Same locality, a, Vir-
gula ; f, Common canal ; th,
Hydrothecae ; x, External
aperture (after Barrancle).

FIG. 203.

U, C, Clhiificiiiii'iijifiif! tiiiiii'ii!!*,
Hall. Ordovician (Trenton
limestone) ; Cincinnati, Ohio.
a, Vertical section, enlarged,
showing central virgula ; 1), In-
dividual of the natural size ;
c, Cross - section, enlarged;
(I, i', I>iplw/raptiis2><tlmeus, Barr.
Silurian ; Prague. Hydrosoma
of the natural size and several
times enlarged (after Barrande) ;
/, Diploijritptniifoluice'us, Murch.
Ordovician (Llandeilo Group) ;
Scotland. Natural size (after
Lapworth).

FKJ. 204.

a, Monograptus greyarius, Lap\v. Sil-
urian ; Dobbs Linn, Scotland. Proximal
end showing sicula, enlarged ; /;, l)'nl innn-
gmptus pennatuhts, Hall. Ordovician
(Quebec Group) ; Point Levis, Canada.
Proximal end showing sicula, enlarged
(after Lapworth).

FIG. 205.

])iplo(jmptus WhitfieliU, Hall. Sil-
urian. Polypary furnished on both
sides with gonangia, probably dehis-
cent. Natural size (after Hall).

near the major end of the sicula, or in alternate sequence along both of the
lateral margins of the sicula ; but in monoprionidiari types the entire polypary
is developed from the minor extremity of the sicula alone. The sicula itself
ceases to grow, as a rule, after the first hydrothecae are budded, and sometimes
it becomes obsolete or absorbed. In many cases it develops into a terminal

HYDROZOA--GRAPTOLITOIDEA

1 1

vehicle, i>r a filiform pn>\ iinal virpila, or aurain into two ipimform »r B

proer^es. Sdinrt inirs tin- hv< lr« •>< iina remains undh idcd, somet inn-s it forms
branches which may diverge at \arioii> aii^'lrs ; in other cases two or four

)iiono]»!-ioni(iiaii polyparies may be placed i»a<-k to back with their dor.-al walls

enali-seiiii,'. thus :,ri\in^ rise to di ..r tetra prionidian colonie-. In tin- latter
types the i-iM-iiitsark i- (•oniiiK.nly divided l»y one or two median septa, and
the primordial luids originate at \ariniis distances along the simlar margin.

( )eea>ional sjteeimens of di|>rioiiidian ( Jrapt "lit es ha\f 1 n found lirarin^

lai'-e -a. • like in- irregularly expanded eorneoiix >t nu-tuivs ( Ki^'. -"•"'). whieh an-
ei.mpai'al.le \\ith the nvai-ian eapsnles (*/'*/////////»/) of recent Sei'inlarians. Furthrf-
moi-e, the singular Ixxlics kimwn as lhui:<niii,i -small, oval, l»ell -shaped. «tr
d.nical chitinoiis ca])sules, which are often a-suciated with ( Iraptnlitrs in vast
nmnliers are re^ardi-d \\\- Nicholson as detached ^raptolitic ^onan^ia.

(Iraptolites coinmoiilv occur in argillaceous schists, more rarely in limestone

formations, of the Upper ('ainl»rian, ( )rdm ician, and Silurian system^. They

si-mi to have swarmed in the mnddiei' portions of the sea, and floated either as

\immin^ colonies, or, in ram- instances, remained stationary u'ith the

'siciila embedded in the mud. They are divided into three groups: — Mn«>-

jir/t, „;,/</,', /iifii-i'niiit't', and JM in/if i,ltn:

Sub Order A. MONOPEIONIDAE. Hopkinson.

uni*-ri"l/f/ i/cri'/ujin/ <>n ////• x/Wr nf jiii/i/jinn/ //////// o

t»

(lein.
•Ia«-kf! J02, 206).

I5arr. ; /'^///"A^//-"/////x and
Hydrosoma undivided, rectilinear, or curved, some-

luri»n(Alnm8

(IrafiMiu
(ii-riiiuny; '', M«

- lnrian

Klintsli.-l.l. Si-i.tlaii.l. Shf.w-
in- sicula (aft.T I.-tp \\nrtli);

tiii-rii-ulntu*.

U-HT. Silurian: I'l-.i-uiMatt. r
I5;uiaii«lc). All ti^'Urrs natural

vii-ian ; I'e.inl l.-vi-, Canada (after
Hall).

•JOT.

Silurian ; Xi-kk.)\vit/,
"r Harramlf).

in-ar

fta.

l>iiliiniiHir»i>t'<!>
<»r.luviriaii ;
(afti-r Hall).

|.,-\ i

a, Hall.
Canada

Hall.
1'uint I

times helicoid. Hydrothecae in contact, usually overlapping. Aperture either

entire or contracted, often directed downwards. Almmlant from base to
summit of Silurian.

118

COELENTERATA— CNIDARIA

liastrites, Barr. (Fig. 207). Hydrosoma simple, spirally coiled. Common
canal very narrow, virgula attenuated ; hydrothecae more or less linear, and
separated from one another by considerable intervals. Silurian.

Leptograptus, Lapw. Hydrosoma consisting of two long, filiform, undivided,
inequal primary branches, with hydrothecae developed from major extremity
of the common sicula. Ordovician.

Coenograptus, Hall (Fig. 208). Two primary branches originating from the
centre of a triangular sicula, curving sigmoidally, and giving off simple branches
from the convex side at tolerably regular intervals. Ordovician.
*~IHdymograptus, M'Coy (Figs. 209, 212, a). Two simple, symmetrically

FIG. 211.

Digeanograptus

ramosus, Hall.
Ordovician
(Hudson River) ;
New York (after
Hall).

:\

FIG. 212.

n, Did ijmnrjrn.pt ux Murchisoni, Beck sp. Ordovician
(Llandeilo Group); Wales, b, Dichograptu* octobrachiatu*,
Hall. Ordovician (Quebec Group); Point Levis, Canada
(after Hall).

FIG. 213.

a, c, Climrn:ograj)t'Ut> t>/]>i<'<tlix,
Hall. Ordovician (Trenton
limestone); Cincinnati, Ohio;
«, Vertical section, showing
common axis in the centre,
enlarged ; b, Polypary of the
natural size ; c, Cross-section,
enlarged. <l, r, DiplogTaptus
palmeus, Barr. Silurian ;
Prague ; <1, Polypary of the
natural size ; e, Polypary en-
larged. /, Diplograptus foli-
uceus, Murch. Silurian (Llan-
deilo Group) ; Scotland.
Natural size.

developed branches springing from a small axillary sicula. Hydrothecae having
the form of flattened rectangular prisms, in contact throughout. Ordovician.
***~Telragraptus, Salter (Fig. 210). Major extremity of sicula giving rise to a
non - polypif erous connecting process (funide) which sends off two simple
branches at each end. Hydrosoma bilaterally symmetrical. Ordovician.

, Salter (Fig. 212, I). Hydrosoma consisting of eight simple

SUB-CLASS i HYDROZOA— GRAPTOLITOIDEA 1 1 9

moiioprionidian branches, which originate from ;is many subdivisions of tin;
funicle ; tin- latter often enveloped in a central corneous disk. Ordovician.

Dicr<in<>'ir"i>tn<, I lall ( Fig. '2 1 1). Hydrosoma composed of two symmet rically
d. -veloped branches which arr coalcseent in the proximal, and free in the distal
portion of their length. Distal end- of hydrot hecar isolated and incurved.
Ordovician.

Sub Order B. DIPRIONIDAE. Hopkinson.

iHJ "f /"'" "/' '//""/' /'« /7/W fOWt "/' /' '/'//'"/A' <'"< jtfii,;,/ 1,,,,-J; I,,
Inn-/:, tritit tin' rir<lill<i< /vw»A'.sr///,/ f» /"''lit " ••••lit ml «

/>/l>/»!/i-<t/>fn.<, M'Coy (Fi^. L' 1 -'5, </, /). Hydrosoma
lineai', diprionidian. Hydrothecae rectangular in
section, inclined, directly overlapping. Vii-gula em-
l»edded in a median septum, commonly projecting
distallv as a long n'bre, and appearing proximally as
a radiele. Primordial buds originating along whole
length of sicular margins. Ordovician and Silurian.

('/iiiKii'iiifi-n/ifii.'i, Hall (Fig. iM:5, u, c). Like the
preceding, luit with hydrothecae separated and stand-
ing nearly vertically ; they are furthermore sub-oval in
section, and distally somewhat .contracted. Ordovician
and Silurian.

PhyUograptos, Hall (Fig. 214). Hydrosoma leaf- KI.:. 214.

like, and composed of four uniserial rows of prismatic /'>< V'".-" •»/''"•-• t"i-
hvch-othecae coalescing along the whole length of their Poin°t I>^B, <Sda. a.sSwai
dorsal margins. Hydrothecae often with two lateral f}5gJiS^^ceti1Sju;
apertural spines. Base of the Ordovician. (p*«r Hail).

Sub-Order C. RETIOLITIDAE. Lapworth.

rk of t/i<' i-nnmum nmnl iiirinif nrii/in in ii Ins>'fi'i1 pn/>/j>trr>/. rift/it/"
<iin/</<' mid rmfi-nl, nr i/tiji/ii-<i/i' "//'/ nffiir/n-i/ to opposite si'lex <>f flic jieri'/t / in :

tin' lilffrr i..< 111 licit iiftt'iniufnl, unit tilji/mrt,;/ H/xni ,i iK'tir,,,']; i,f dlitlHOUS fibt'CS. ^i''H/"

absent.

Ufa, llai-r. (Fig. 215). Hydrosoma undivided, elongate, compressed, and
tapering toward the extremities. Hydrothecae disposed in rows on each side
of the axis, inclined, and in contact with one another. Virgulae two in number,
separated, and attached to opposite sides of the peridermal network in the
median plane of the hydrosoma ; one is rectilinear, the other zigzag-shaped.
Ordovician and Silurian.

Sftomaiograptus, Holm; /.V/^/.v/y./y/s, Hall; £/»»•".'/''"/''"'• Emmons. Or-
dovician.

Range and Distribution of the Hydrozoa.

Of the Hydio/oans in which preservation is at all possible, the 7/W/v«-i*/W-
Unae are known with certainty as far back as the Upper Cretaceous. During
the Tertiary period they achieved a s..mewhat greater distribution, but have

120

COELENTERATA— CNIDAHJA

CLASS II

only recently begun to enter extensively into the formation of coral-reefs and

other calcareous deposits.

In the Upper Jurassic, notably in the Tithonian of the Mediterranean

district, certain of the Hydractinidae (Ellipsactinia, Sphaeractinia) are very

plentifully distributed ; while, on the other hand, both the Triassic genus Heter-

astridium, and the genera Parkeria and Porosphaera, occurring in the Cretaceous

of Northern Europe, belong to the rarer fossils.

Of vast importance as rock-builders, however, were the Stromatoporoidea of

the Palaeozoic era. They occur profusely in the Ordovician and Silurian strata
A p of North America, England, and Russia, and

particularly in the Middle Devonian of the Eifel
and Ardennes, as well as in Nassau, Devonshire,
. the Ural Mountains, Spain, etc. They frequently
attain gigantic proportions, and are an essential
constituent of the limestones and coral reefs of
the Silurian and Devonian periods ; but they
do not survive beyond the Palaeozoic era.

The Gmptolitoidea, under which head the
Cladophom are also commonly included, are con-
fined to the Upper Cambrian, Ordovician, and
Silurian periods. They are profusely distributed
in the silicious schists and alum -slates of the
Fichtelgebirge, Thuringia, Saxony, and Bohemia.
They are plentiful also in the Harz, in Poland,
Silesia, the Baltic Provinces, and the Ural district ;
and again in Scandinavia, Cumberland, Wales, the
north of England, Scotland, and Ireland, as well
as in Normandy, Brittariy, Spain, Portugal,
Sardinia, and Carinthia. In America they are
found exquisitely preserved in Newfoundland,

Canada' New York' Virsinia' Teiinessee> Ohio>

B, Cross -section, c, Lower end, en- Wisconsin, and Iowa. They are known also in

larged ; calcareous matter dissolved ot .LI A • /T> T • \ i A T i

out by acid, v, zigzag-shaped vir«*uia • South America (Bolivia) and Australia, and are

not uncommon in the drift which covers the

ih

F«t. 215.

necting the virguiae ; o, Apertures plains of Northern Germany.

(after Holm). ;

According to Lapworth, the Graptolites are

distributed vertically throughout six different horizons; the first of which
coincides with the Upper Cambrian, the three following with the Ordovician,
and the two uppermost with the Silurian. The Monoprionidae are especially
characteristic of the two Silurian horizons.

Sub-Class 2. ACALEPHAE. Cuvier. Scyphomedusae.
(Discophora, Huxley.)

Free-swimming, discoidal, or bell-shaped Medusae, with downwardly directed mouth,
with gastro-vascular pouches and numerous radial canals, and fairing, as a rule, the
margin of umbrella lobed. Cambrian to Recent.

The Acalephs or Lobed Jelly-fishes, though frequently of considerable size, are
entirely without hard parts, and therefore are singularly unfitted for preservation.

BUB-CLASS II

HYDROZOA— ACALEPHAE

121

FIG. 210

Eichstiidt, Bavaria,
in^outliiie.)

1/7 natural size. (M

.itho-rnphic slat'-s :
issing parts restored

1'nder exreptioiiallv ta\ ..arable conditions, however, ;is in tin- Lithographic
Slat.-s (I'pprr Jurassic) ,,f Kirlistadt and Sul.-nbofen, impressions ..f these deli-
cate organisms are sometimes pre-
served, which admit of accurate

iatic determination,

The best preserved and at
tin- same time the most abundant

speriesis/i'///'»7"/////rx ii>!i,,ii-<i/i<!it.<, /;:-:;-'
Hacckcl, bclongini^o tilt- Arras- /:;V.r

pcdotc t'.-m lily of Rhizoetomidae.
Impressions also occur in flinty
concretions of the Upper Cre-
tacruus, which arc most nearly
referable to tin- Medusae. Of a
more <|iiestional»le nature are the
organisms occurring in the Cam-
brian sandstone of Lugmies,
Sweden, and described liy Torrell
under the name of Spofangopsis,
luit which Xathorst assigns to the
Acalephs. In the same strata
also are found those peculiar
t'ucoidal structures known as
Knjiliifttm-j which are generally
supposed to be of A-egetable
oii^in. Xathorst has brought forward evidence, however, to show that these
may really have been produced by the trails of Jelly-fishes. Here also should
be noticed the forms described by Nathorst as Medusites, from the Lower
Cambrian of Sweden, which this author regards as casts of the gastric cavity of
Jelly-fishes. According to Walcott, similar fossils are common in Alabama.1

'/'.. .M.-nioir on the Anatomy and Affinities of the Medusae (Phil. Trans.), 1849. — Kn>',\
/.'.. !Yl,.-r rinr Mrdnsr in F.-u«-r>trm BttznngBber. Wi.-n. Akad. Bd. LILfc 1865.— Haeckel, E., Ueber
foodie M.-duscii (Z.-itselir. fiir wisst-iiM-haft. Zodl. lid. XV. and XIX.), 1865 and 1870.— Neues Juhrk
fur MiniTiilngie, 1866.— Jenaisclir Zi-its<-hr. Bd. VIII., 1874.— System der Meduseu, Bd. I. and II.,
.Ii-na, 1880-81.— Nathorst, A. G., Om Aftryck af Medusor, etc. (K. Svenska Vetensk. Akad. Handl.,
IM. XIX.), 1881.— A,,,,,,,,,,. L. /-., Ueher jurassische Meduseu (Abhandl. k. baier. Akad. Bd. XVII.),
1883.— A'/-"//'//. -I.. Uebet f..ssilc Medusen (Mem. Acad. Imp. St. Petersb. vol. XVL, 7th Ser.), 1871.

/'"lifi'l, //.. AltiH-nuivlie .Medusen (Festschrift zum 70ten Geburtstage R. Leuckarts), 1892. —
//•>//, ./., Palaeontology of N.Y., vol. I.. 1847, and III., 1859.— 20th Report N.Y. State Cabinet
X.-it. Hi>t., l.xti.S.— /,^>*/v>r<A, C., Notes on British Graptolites (Geol. Mag. X.), 1873.— Hopkinson, J.,
ini.l Liijiinn-ih. c., (Jraptolites of tli«- Arenig and Llandeilo rocks of St. David's (Quar. Journ. Geol.
CXI. . 1875. — Linnarsfton, (/., and ^V/W/o/sv,,,, //. A., On the vertical range of Graptolites in
Sw.-dn; . III.), 1876,—Lapworth, C., On Scottish Monograptidae (Geol. Mag. III.), 1876.

On thr (Jraptolit.-s «,f County Down (Ann. Rep. Belfast Nat. Field Club, I., Part IV.), 1877.—
//" «/•/, A'.. I Mr Fauna «lrs Graptolitlien-Gesteins (Neues Lausitzsches Mag. LI V.), 1878. — Kayser, E.,
In Alihandl. gi-ol. Spocialkarte von Preussen II., Heft 4, 1878. — Linnarsson, G., Om Gotland's
<:rapt«.lit.-r Svms. Vet. -Akad. Forh. XXXVI.), 1879,—Lapworth, C., Distribution of the Rhabdo-
plioia Ann. Majr. Xat. Hist. III.-VI.), 1879-80.— On new British Graptolites (op. cit. V.), 1880.—
TiiWn-fii, N. J.. i Mi spn-i.-s of I )id viuograptus (Geol. For. Stockholm Forh. V.), ISSO.—Toruquisf,
X /... Studi.-r r.fv»-r lU-tiolitcs (Geol. For. Stockholm Forh. V.), 1881. Also papers by Tb'rnquist
and Liiinarssnn in sanir volume, pp. 292-326.— Holm, G., Skandinavien's Graptoliter (Sveus. Vet.-
Akad. Forh. XXXVIII.), ISSl.—TuUberg, S. A., Skane's Graptoliter (Sven. Geol. Underslikn., Ser.
<'-. I. and II.\ lSS2-S3.—8frencer, J. W., Graptolitidae of the Upper Silurian System (Bull. Univ.
Mo. I., and Trans. St. Louis A. ad. Sci. IV.), 1884.— Jaekel, 0., Ueber das Alter des Graptolitheu-
• J.-sti-ins iZ.-itsrlir. dentsch. geol. Gesellsch. XLI.), 1890,—Barrois, C., Memoire sur la distribution
dcs Graptolites en France (Annal. geol. soc. Nord), 1892.

Sub-Kingdom III. ECHINODERMATA

To the Echinoderms belong radially or bilaterally symmetrical animals, which
were formerly included with the Coelenterates under the general category of
Radiata, ; but were recognised by Leuckart as the representatives of a distinct
animal type. They possess a well - developed, usually pentamerous dermal
skeleton, which is composed of calcareous plates, or of minute, isolated, cal-

FIG. 211

«, Magnified cross - section of an
Echinoid spine ; Fiji Islands. &, Mag-
nified section of coronal plate of a
recent Sea - urchin (Sphaerechinus) ;
plane of section parallel to surface.

218.

Pentacriims snlteres, Goldf. Upper Jura ; Reichen-
bacli, Wurteinberg. c, Vertical section of stem-joint in
plane indicated in c. 18/] ; ?>, Transverse section of
same. 18/j ; c, Joint -face; </, Side view of column
(natural size).

careous bodies embedded in the integument ; the exoskeleton may be more or
less movable, or even immovable, but is very frequently provided with move-
able appendages (spines, bristles, pedicellariae, etc.) The arrangement both of
the skeletal parts and of the principal organs is so generally pentamerous, that
five may be regarded as the fundamental numeral pervading the whole sub-
kingdom of Echinoderms.

SUB-BRANCH I

I'KI.MATOZOA— CRINOIDEA

123

Apart from this constitution.-!! din"crence. thr Kdiin- u dist inguishcd

from tin- Coelenterates by the presence of a true- digestive canal, a vascular
•VStem/and water \aseular apparatus : by a more perfectly <!«• vclojic. I nervous
system ; and liy an exclusively sexual mode of reproduction.

The most striking ditl'erencc consists clearly in the nature and composition

of thr «• \oskeletoll ( Kigs- l' 1 7. I1 1 S ). All of the pi plM, .-| ii 1 1'-, a II' 1

other indurations an- >ecivteil in the integument (dermal connective tissue),
and are all composed of microscopically small calcareous liodies embedded in
organic matter. As these liodies are united to form perforated hori/ontal
laminae, which are connected with one another by \ertieal pillars, the result is
a minutelv reticulated structure, highly characteristic of all Echinoderms.
During fo»ili>ation the interstices are commonly infiltrated with lim-
Inmate, so that the whole structure is transformed into calcite, exhibiting un-
mistakable rhombohedral cleavage. Kach plate, joint, and spine of a sea-urchin,
Martish, or crinoid lieha\es mineralogically and optically like a single calcite
crystal. >.

All the Kchinoderms are marine. In the classification proposecMvf Haeckel
thcv are divided into three primary groups comprising the following classes : —

Sub-branch A.

/"Class 1. Crinoidea.
Pelmatozoa. - „ 2.

Sab-branch B. Asterozoa.

Suh-hiuncli ('. Echinozoa.

I „ 3. Blastoideu.

( Class 1. Opkiuroidea
\ „ 2. Asteroidea.

(Sea-lilies.)
(( 'ystideans.)
(Blaatoids.)

(Brittle stars.)
(Star-fishes.)

TClass 1. Echinoiden. (Sea-urchins.)
\ „ 2. Holotliin'i'il,l>,i. (Sea-cucumbers.)

SUB-BRANCH A. Pelmatozoa. Leuckurt.

The a are Echinoderms which, during the whole or at least the"

earlv poll ion of their existence, are fixed liy a Jointed, flexible stalk, ol' ale
attaehed l»y the dorsal or al»oral surface of the body. The principal viscera are
enclosed in a lnirsifonn, cup-shaped, or spheri«-al test ('•"///.'•), which is composed
of a M-stem of calcareous plates ; and on the upper surface of which are situated
lioth the mouth and anus, as well as the ainlmlacral or food grooves conducting
to the mouth. Asa rule, jointed flexible arms spring from the distal ends of
the ambulacral grooves around the margin of the calyx; sometimes, however,

arms are wanting, the amluilacral areas licing extended down the >ide> of the
cal\-\, and Keset on l>oth sides with ji-nnules (Blastoidea). The inferior (dorsal,
al>oral) portion of the calyx is composed of a single or douMe series of l»asal
plates, \\hieh either rest directly upon tin- stalk, or are grouped aliout a rentro-
dorsal plate.

The /'ilni'ifm.Hi are diviiled into three classes: — Crinoideii, C>/.-f"i<f<", and
Blasl>'i>l'-ii. nf thc.M-, only the Crinoids are 1'epresented by a few existing
genera ; the others are wholly extinct, and are confined, moreover, to the
hilaeo/.oic rocks. Although tlie Cystideans possess a less highly specialised
organisation than the others, and probably represent the common ancestral

124 ECHIXODERMATA— PELMATOZOA SUB-KINGDOM in

type from which both the Blastoids and Crinoids have been derived, neverthe-
less, it is expedient to treat of the Crinoids first, since a knowledge of the
anatomy in recent forms is essential to an adequate conception of the extinct.

Class 1. CRINOIDEA. Miller, Sea-lilies.1
(Brachiata, Bronn ; Actinoidea, F. Eoemer.)

Usually long-stalked, more rarely non-pedunculate and sessile, occasionally free-
swimming Pelmatozoa with calyx composed of regularly arranged plates, and provided
with well-developed movable arms.

The Crinoid organism consists of three principal elements — calyx, arms,
and stalk. The calyx and arms together are sometimes spoken of as the
crown, as contrasted with the peduncle.

1. The Calyx. — The calyx has usually the form of a cup-, bowl-shaped, or
globular capsule, within w^hich the more important organs are enclosed. Its
lower (dorsal or abactinal) surface commonly rests upon a peduncle (Fig. 219) ;
but in some forms it is attached directly by the base, and in rare instances it is
free. The superior (ventral or actinal) surface is either membraneous or plated ;
it carries the mouth and ambulacral grooves, and hence is homologous with the
under side of a star-fish or sea-urchin. As a rule, only the inferior and lateral
portions (dorsal cup) of the calyx are visible, owing to the concealment of the
summit by the arms. The cup is constituted of two or more circlets of plates,
which are uniformly oriented with reference to the ambulacral organs.

a. By the base is understood the one or two rings of plates intervening
between the topmost joint of the column and the first cycle of plates situated
in the projection of the ambulacra or arms. When the basis is monocyclic
(Fig. 220) the position of the proximal ring of plates is interradial ; but when
dicyclic it is radial, and the upper ring corresponds with the basals of mono-
cyclic forms.

In the nomenclature of P. Herbert Carpenter, the upper series of plates in

1 Literature :

Miller, J. S., A Natural History of the Crinoidea or lily-shaped Animals. 1821.

Millie/; ,/.,Ueber den Ban des Pentacrinus cuput medusae (Abhandl. Berliner Akacl.), 1841.

de Koninck, L. 6-'., et le Hon. H., Recherches sur les Crinoide.s du terrain carbonifere de la Belgique.
Brussels, 1854. (Very extensive bibliography.)

Be I/ rich, E., Die Crinoideen des Muschelkalks (Abhandl. Berliner Akad.), 1857.

Schultze, L., Monographic der Echinodermen des Eifler Kalks (Denkschrift der k. k. Akad. der
Wissenschaften), Vienna, 1866.

Sltu/nard, B. F., Catalogue of Palaeozoic Echinodermata of North America (Trans. St. Louis Acad.
Sci. vol. II.), 1868. (Very complete bibliography.)

Carpenter, W. B., On the Structure, Physiology, and Development of Antedon rosaceus (Philo-
sophical Transactions Royal Society, vol. CLVL), 1876.

Wachsnndh, C., and Springer, F., Revision of the Palaeocrinoidea. I. — III. (Proc. Acad. Nat. Sci.
Philad.), 1879-86.

Wachsmnth, C., and Springer, F., Discovery of the Ventral Structure of Taxocrinus and Haplocrinus,
ibid., 1888.

Wachsmuth, C., and Xjiriiv/er, F., The Perisomic Plates of Crinoids, ibid., 1890.

Wachsmuth, C., and Springer, F., The Crinoidea Camerata of North America. (In preparation.)

Loriol, P. de, Paleontologie Francaise. Crinoides Jurassiques, I. — II., 1882-89.

Neumayr, J/., Die Stamme des Thierreichs. Band I., 1889.-

Af/assiz, A., Calamocrinuq Diomcdae (Memoirs Museum Comp. Zool. vol. XVII.), 1892.

Bather, F. A., British Fossil Crinoids (Ann. and Mag. Nat. Hist. (6th ser.), vols. V.— VII.), 1890-92.

Bather, F. A., The Crinoidea of Gotland (K. Svenska Vetensk. Akad. Handlingar, vol. XXV.), 1892.

C'lMNulhKA

125

tin- dicvdic forms ;iiv properly termed //i/sr//x, and tin- lower Berjea nii'

The basals as thus defined are e<|ui\ alent to tin- " parabasals " in

Fro. 219.

S S/l!l'-

Lng. staik.-d

Crin.ii.l with dieyHir

ad anal inter-

radius. ". Anals; I,

b, [nfrabasals.

(Ki-hi and left sides

. atVr Au-

gdin.)

Arti i/ni'ri a us jn'iilxisi-liliuH.-i, Hall. Pro-
jection of calyx showing the three kisal*
(b), 5x3 simple radials (?•), four paired inter-
rays (/(•)) ni"l ;l lit'th unpaireil anal interray (")•

Fi'.. -J-J1.

I'nti-riiii'i'in us in ulti jili'f,
Traut. Calyx with <liey-
clic base, radials, costiils,
and distiehals.

' subradiale " of do

tin- older nomenclature of Johannes Miiller, and to the
Koninck and other authors.

Both K-isals and infraliasals are: primarily five in number; but owing to the
fusii in of two or more of the proximal plates, the number of basals in the
niiHHK-yclic forms may be reduced to four, three, or even to two, and that «>f
infrabasalfl in the dicyclic to three. During the
ontogenetic development of the recent Antedon, a
UK m- or less complete resorption of the basals has
lift-n ol»scr\fd ; and tin- same probably also held
true tor certain Mesozoic genera (A1/^-// ///'•/•/'////.<,
In many of the non-pedunculate
(/'////"'•//////>•, Marsupites, Fig. 222) an
additional plate known as the »•/ ntmdwsal rests
against the infraliasals, and jjj-i.baldv represents
an atrophied stalk. The Itasals ar«- united with
one anot her and with the overlying radials l*v
close sutures, and are immovably held together
l»y tihrnus connecti\e tissue. 'ITimgh usually
sim mill, the joint faces are sometimes striated,
and are visiKle externally as incised lines.

/>. Succeeding the l>ase is a cycle of five (rarely four or six) plates, which,
on account of their position with reference to the rays, are called radials. The
radials form the sides of the calyx in nearly all Mesozoic and Recent Crinoids,
and give origin directly to the arms, which may become free immediately aliove
the radials, or may be incorporated for some distance in -the calyx, either by
means of supplementary plates, or by lateral suture among themselves.

FK.. •_'•_••_'.

Sehlot. sp.

126

ECHINODERMATA— PELMATOZOA

SUB-KINGDOM III

The upper boundary of the calyx is differently demarcated by different
authors. Many assign all the plates above the first cycle of plates in each ray
to the arms, even when they are immovably united with one another at the
sides ; while, according to Schultze and others, the arms begin invariably at the
•point where they first become movable, i.e. above the first articular facet. The
latter course is open to serious objections, inasmuch as strictly homologous
parts receive different appellations in different groups.

Carpenter, Wachsmuth, and Bather restrict the term " radial " to the lower-
most circlet of radially situated plates, and speak of the succeeding cycles as
far as and including the first axillary plate as bmchials (distinguished as first,
second, and third costals, distichals, and palmars respectively), in all cases,
whether the plates are free or fixed.

In most Palaeozoic Crinoids one or more interradial plates are intercalated
between two of the rays, and in line with the anal aperture ; these are called
the anal plates or anals. If a plane be passed through the latter and through
the radial situated directly opposite, the calyx will be divided into two
symmetrical halves : the parts lying to the right or left when viewed from the

i

FIG. 223.

l'i nt/ii'i'lnus civputmedusac, Lain. sp.
Ventral disk constructed of very thin
perisomic plates, with central mouth
(o), open ambulacra, and eccentric
anus (A).

FIG. 224.

Hyocrinus Bethellianus,"Wyv. Thorn. Recent.
Ventral disk, enlarged, o, Orals ; p, Mouth
(peristome) ; s, Covering plates; c, Dorsal
canals of the arms ; am, Ambulacral furrows of
the arms ; an, Anus (after Wyville Thomson).

posterior or anal side" are so designated ; while the anterior side is that opposite
the anal interray. Interradial plates, however, are not confined to the anal
interray, but are frequently developed also between the other rays, when the
calyx is correspondingly expanded. If several cycles of radials are present, an
equal number of interradials are also developed, and are distinguished in like
manner as interradials and distichal interradials of various orders. The anal
interray is frequently characterised by the peculiar number, size, and position
of the anal plates.

c. The superior side of the calyx is known as the tegmen calyds. The
covering may be in the form of a coriaceous skin, in which large numbers of
thin calcareous ossicles are embedded (Figs. 223, 224), or of a plated disk
rising from the base of the arms. It frequently exhibits a more or less central,
externally visible mouth -opening, and a usually eccentric interradial anal
aperture. The mouth opens into an oesophagus and thence into the expanded
visceral mass, which fills the greater portion of the inner cavity. The intestinal
canal is directed - downwards at first, and after numerous windings discharges
into the anal opening. In certain fossil Crinoids (Actinocrinidae) the digestive

CLASS I

CIMNOIDKA

127

apparatus is represented by an extremely thin -walled, finely perforated, con-
voluted Unly, which occupied the vertical axis of the body cavity, and was
contracted into a narrow tube toward the base (Fig. 232).

In all recent (Yinoids fiv<- (occasionally four) open ambulacra! furrows lined
with epithelium conduct from the mouth to the tips of the arms, remaining
either simple or subdividing as often as there are arms. Underneath the floor
of the grumes runs an ambulaeral vessel tilled with water ; and accompanying
this are the blood and vascular canals and a nervous cord. Distensible tentacles
pass out from alternate sides of the ambulacra, and the latter unite to form a
circumoral /•///'/ ni/ni/. From the ring canal five short open tubes (stone or
Water «•«////'/>•) extend downwards into the body cavity and supply the ambulacral
system with water.

In the recent genera, T/iaumatocrinus, Ithizocrinus, Calamocrinus, Hyocrinus
( Kig. L'L'l), and in a large number of fossil Crinoids, a triangular oral plate is
>ituated in each of the five angles of the mouth-opening. The apices of the

:. 825.

I.l-l-l/t,, : !: I'lll ,/,/.»•.

Miiller. Ciin.iici wjth .-ion-

Katrtl anal tube (after
Scluiltze)

, iii riini^ i/ui iii/iii'Ii ilnix, Hall sp.
Specimen showing plates <>f the tei;-
inen ami eccentric anus.

FIG. L'i'7.

<"/"'.-• rosaceits,
KIIIMU. Devonian ;
Eifel. Calyx witli ven-
tral pavement, twice en-
larged (after Schultze).

nrals are diivctrd towards one another, and between them run the ambulacra.
The plates arc extremely \ariable in size; and although well-developed in the
larvae of Jutn/nn and I'nihi.-rinus, they become wholly resorbed before maturity.
In a number of Palaeozoic Crinoids (Larmfarmia, Fig. 227) the summit is
entirely <>r in large part composed of five oral plates which may be either
laterally in contact or separated by furrows. More frequently, however, the
orals occupy only the angles of the mouth-opening, the remaining area between
the ambulacra] furrows being covered with more or less regularly arranged
inttrambuiacral plates (Fig. 224). In most of the Palaeozoic Camerata, and the
recent Calanworinus, the anus is placed at the upper end of a tube known as
the anal ////*• or profacis. In the Fistulata, however, the anal opening is situated
along the anterior side of the ventral sac, or between the sac and the mouth.

<>t the interaml.iilacral plates a greater or smaller number (in Calamocrinus
all in the vicinity of the mouth) are perforated by respiratory pores for the
admission of water into the inner cavity. Pores evidently performing a
similar office occur in some of the Fistulata; but these, instead of piercing the

128

ECHINODERMATA— PELMATOZOA

SUB-KINGDOM III

body of the plates, enter only their outer angles. Other Fiatulata have a
madreporite.

The ambulacra are frequently lined along their sides by perpendicular,
\\ edge-shaped side-plates, and these are surrounded by movable covering pieces, both
of which extend from the mouth to the ends of the arms. In the Palaeozoic
Taxocfinus (Fig. 228), the covering pieces are arranged in alternate rows, with
side 'pieces adjoining them. The latter plates occur also in most of the Fistula fa
and Articulata, but are rarely represented in the Camerata. The mouth may
be exposed or closed; being either surrounded by five oral plates (Taxocrinus,
Fig. 228), or the posterior oral may be pushed in between the four others, so
as to conceal the mouth ; the latter is then said to be subtegminal (Fig. 229).

A very remarkable modification of the ventral disk occurs in the Palaeozoic
Camerata. Here the usually very numerous plates attain considerable thickness,
and fit into one another like the stones of an arch to form an extremely rigid,
more or less convex vault, which is sometimes surmounted by an equally rigid
plated proboscis. At the apex of the dome five large-sized plates are often

FIG. 228.

Taxocrinus intermed-
ius, W. and S. Ventral
disk (after Wachsmuth
and Springer.)

PIG. :>•_". >.

Platycrinus Haiti, Shuni. Projection
of ventral disk, o, Anibulacrals ; in, In-
terambulacral areas ; in', Anal inter-
radius ; e, Covering pieces of the anibu-
lacrals ; i, Interradials ; p, Anterior
and lateral orals ; o, Posterior (anally
situated) oral ; x, Plates of the anal
interambulacral area (after W. and S.)

Fie. 230.

He.iucrtnus elonyatus, Goldf. Calyx
with tegmen. a, Profile; I, Aspect
from above.

distinguishable, of which that lying in the anal interradius commonly differs
from the rest in form and size, and appears to be wedged in amongst the others.
These five plates are identified by Wachsmuth and Springer as orals. The
remainder of the tegminal plates are distinguished according to their position as
ambulacrals arid interambulacrals ; in most of the Actinocrinidae the ambulacrals
are not arranged in alternate rows (Fig. 231), but frequently consist of large
single plates of one or more orders, which are separated from one another by
the continuous interposition of supplementary pieces. In other groups, notably
the Platt/crmidae, the ambulacra are generally arranged in two rows of rather
large plates, which, however, lose their original character to some extent. The
interambulacrals usually meet with the interbrachials. The tegmen of the
Camerata, as a rule, is composed of large nodose plates, for the identification of
which considerable experience is required.

Most of the Palaeozoic Crinoids have but a single opening in the tegmen,
which is interraclial in position, and undoubtedly represents the anus. With
the exception of the Ichthyocrinidae the mouth is subtegminal, and the food
grooves are rigidly closed. In many cases the covering pieces are pushed

CLASS I

CRIXOIDEA

129

inward, and the ambulacra follow the inner floor of the tegim-n, forming a
skeleton of ramifying tubes ; these are conducted along open galleries from the
mouth to tin* arm opening ( 1'V -•">-, A).

2. 77*0 Arms (Brachin). — The arms of the Crinoid body form the immediate
prolongation of the radials. The plates of the arms are termed brachiah, and

Fio. 231.

Aijiinnx-r'nnis Aniericanus,
Roen'i. Ventral disk, r, Uni-
serial anibnlarrals ; /', Interaiii-
bulacrals ; n, Anally situated
oral ; /i. Anterior and lateral orals ;
Posterior interaniljulacrals
(after \Vai-hsnnith and Springer).

Fio. 232.

Actinocrinus proboscidicdis, Hall. A, Plates of tegtnen partially
removed in order to show the covered ambulacral passages (a)
leading from the arms to the mouth. Ji, Plated upper surface
of ambulacral galleries. C, Natural cast of ventral disk with
impressions of calyx ambulacra (n) leading to the mouth (o);
an, Anus.

arc arranged either in single or double alternating rows ; and hence are spoken
of BB uniserial (Fig. 233, A), or as biserial (Fig. 233, B). The plates of the
i mist-rial arms may be either rectangular or cuneiform, the major ends being
directed alternately to the right and left. In biserial arms the smaller ends of

•••unfit.*, An;;, sp., showing

uniserial arms. /;, i;,l/;,-ri,iii.* <;>xt<itus, llising.,
with hiserial aims (after Angi-lin).

Fio. 234.

Plated ambulacral furrows of the
arms, a, b, Cyathocrhm* /-HHIUS*'*,
Ang., showing covering pieces ;
c, GissQcrinus arthritiots, Uising.,
with covering pieces. All liguivs
enlarged.

th<- plates meet midway, so as to form a zigzag suture. The arms invariably
bi'gin uniserially, the biserial structure being gradually introduced in an upward
direction. The arms either remain simple, or branch in various ways ; the
plates upon which a bifurcation takes place are called axilla ri<*.

In the Camerata, the more highly organised Fistulata, and in all recent

VOL. I K

130 ECHINODERMATA— PELMATOZOA SUB-KINGDOM in

Crinoicls, the arms are furnished with pinnules, which are given off alternately
from opposite sides, one to each arm-plate. The pinnules are jointed appen-
dages, which repeat the general structure of the arms, and in living Crinoids
lodge the genital organs. When two or more arm-joints meet transversely by
a rigid suture, and only the upper one is pinnule-bearing, those joints form a
syzygy, whether their apposed faces are striated, dotted, or smooth. The lower
joint bearing no pinnule is called the hypozygal joint, the upper one the epiri/gal ;
and the two together constitute physiologically but a single segment, as is
shown by the alternation of the pinnules.

Both arms and pinnules are traversed ventrally by a deep groove (ambulacra!
or arm furrow), at the bottom of which is situated a tubular prolongation of the
body cavity (the so-called coeliac or dorsal canal) ; overlying the latter run the
genital, water, and vascular canals, a nervous cord, and two rows of tentacles.
The furrows of the arms enter by the arm-openings into the tegmen, and all
converge to the mouth. Food-particles, consisting chiefly of diatoms, irifus-
orians, and microscopic crustaceans, are propelled along the furrows and into
the body by the action of cilia.

In all recent arid in numerous fossil Crinoids the arms are perforated in the
dorsal half by a single, or in some cases by a duplicate axial canal (axial cord),
containing elastic fibres and a nerve-band, the latter frequently giving off
delicate branches with ramifications in every direction. The dorsal canal ex-
tends also into the radials and basals, perforating the plates when they are
thick, and running in a shallow groove on the inside when thin. So far as
has been observed, the axial canals begin uniformly in the basals, where they
divide dichotomously ; but in the radials the branches generally reunite to
form the so-called ring canal (Fig. 276).

3. The Column. — The stem or column attains in some forms (Pentacrinus) a
length of a number of metres ; but in others it is much abbreviated, or even
atrophied, so that the calyx is either directly adherent by the base (Cyathidium),
or is destitute of all means of attachment (Astylocrinus, Uintacrinus, Marsupites,
Antedon). The stem is composed of short segments, having either circular,
elliptical, or angular (especially pentagonal) cross-sections, and being sometimes
of uniform and sometimes of variable proportions. Lateral appendages, called
cirri, are present in numerous forms, being given off either singly or in whorls
at certain intervals along the periphery. The larger and all cirrus-bearing
segments are called nodal joints, and those interposed between them the inter-
nodal joints. The distal end of the stalk may taper gradually to an apex, in
whose vicinity fine radicular cirri are commonly developed, or, it may be
thickened at the extremity so as to form a bulbous or branching root. Growth
is accomplished by the insertion of new joints at the proximal end of the stem,
the earlier segments becoming at the same time gradually enlarged. The last
formed joints are commonly of smaller size than those situated more remotely
from the calyx. In the early stages of Antedon the column is terminated dis-
tally by a large so-called dorsocmtral plate.

All the joints of both the stem and cirri are pierced by a central longi-
tudinal canal, which is either round or pentagonal in cross-section, and com-
municates with a peculiar dorsally situated chambered organ. The latter is
supposed to represent the central nervous system, but contains in addition a
vascular organ that has been regarded as a kind of heart. The axial canal of
the stem is encased in a sheath of elastic tissue which serves to bind the in-

CEINOIDEA

rd

dividual >e-mcnt> together. Tin- union i> further M ren-t hem-d l.y siituiv>.
the appos.-d faces «>f tin- joint- lii-in^ tor tin- most |iart fiat, and cither radially
-triated, 01- diversified in \arioiis ways l.y ]>roinine!ices and ; he ^roo\ ••>

In-ill-' likewise occupied l.y conneeti\e tissue. Smile! ime> tin- :I|J|M.-.-. :
are -niooth and rigidly united with one another ( /•„'//••/•/// //•>-, etcj ; l.nt in
Other cases an articulation is >emred l.y means of an elevated usually oblique
fulcral i-id^f (/////:»«•/•/////.<, /Ai// /•»///'/"«•/•/////>•). The proximal segments ot the
eoliinin occasionally exhibit sini|.le vertical clefts whi«-h indicate an original
• |iiiiH|iii]iartite composition. These divisions always occur alternately with
those of the l.asals in monocyclic, and with those of the infrabasals in dicydie
forms.

(hdn^uij. — Although \\e are acquaint ed as yet with the life -history of
I. ut the single genus .////MA///, the phenomena of its development are of such
H-niticam e as to shed most valual. le light upon many con-
ditions ol.served in fossil Crinoids. Following impregnation,
the ova perform the early stages of development within tin:
ovarian glands of the j.innules. Immediately after escaping
from the \itelline membrane the embryo is girded with four
tran>\er>e ciliated Lands, possesses a laterally situated mouth,
and bears considerable resemblance to certain Annelid em-
bryoes. Delicate plates of calcareous network (which, when
definitely developed, are ten in number) are next formed
within the wider anterior portion of the gastrula larva; these
are arranged in two transverse rings, the plates of the anterior
>eiie> being plaeed symmetrically above those of the posterior.
K\ tend in- from the centre of the lower row downwards and
backwards, a series of delicate calcareous rings may now be
observed, at tlie base of which a large cribriform plate is
rapidly developed. The two rows of plates gradually become
enlarged, and the outline of the rudimentary calyx is more
clearly defined, while sheaves of parallel calcareous rods are
>een pa-Hii- through tly rin-s of the rudimentary stalk. The
hitherto free-swimming larva now becomes fixed, the ciliated
bands disappear, the outer surface becomes invested with a
thick sari-ode layer, and the mouth appears as a lar^e patent
opening "••eiipyin:;- the centre of the cup. The five plates
surroundin.u the mouth are termed the orals, and the five con- *al, *,.:,].
stitutin^ the proximal series the basals, which rest directly dowd
upon the tupnio>t segment (centrodorsal) of the stalk. In
the five diamond-shaped spaces which are left between the divisions of the
urals and ha>al> delicate net like plates ( ra dials) are next formed, which increase
rapidly in si/e and intrude upon the orals. At the same time a sixth plate
(anal) makes its appearance in the zone of radials, but is gradually forced
upward with the orals into the ventral disk. Rows of elongate cylindrical
segments (brachials), which grow very rapidly, are next given off by the
radials, when the larva is said to have reached the " Pentacrinus stage."
Simultaneously with the development of the arms and column, a resorption of
the anal and orals occurs, which plates are obliterated on the completion of the
dermal skeleton. The basals also become obsolete, owing to the encroachment
of the centrodorsal, and are indicated in the adult form by a mere rudiment in

s]

w.wiii.-

132 ECHINODERMATA— PELMATOZOA SUB-KINGDOM m

the form of a small ring-like rosette. Finally, the button-shaped centrodorsal,
which is now beset with numerous cirri, detaches itself from the stalk, and the
creature becomes capable of independent motion.

The ontogeny of Antedon reveals the fact that the basals, orals, and stem
represent the most primitive skeletal structures, while the radials and brachials
are formed at a subsequent period. Similar evidence is afforded by numerous
fossil Crinoids, in which the basals and column are very strongly developed,
while the radials are mostly of inferior size, and the arms either rudimentary
or absent.1

Habitat. — Existing Crinoids live together in large numbers, and inhabit
depths ranging from shallow water to a maximum of about 3000 fathoms.
Their distribution, however, is mostly very local. Fossil Crinoids also appear
to have been gregarious in habit, and their remains are frequently found com-
mingled with those of reef-building corals in Palaeozoic strata. Owing to the
extremely delicate constitution of many of the skeletal parts, and the looseness
with which the plates and segments are united, the Crinoid organism is by no
means favourably adapted for preservation in the fossil state. Perfect crowns
are of comparatively rare occurrence ; but, on the other hand, detached joints
of the stem and arms are often very abundant, and occasionally form beds of
considerable thickness. Crinoidal limestones of greater or lesser extent are
met with in numerous formations from the Ordovician to the Jura ; those of the
Carboniferous and Muschelkalk (Trochitenkalk) being especially characteristic.

Classification. — The first attempt to construct a classification of the Crinoids
was that of J. S. Miller in 1821. Four groups differing in the form and mode
of union of the calyx plates were distinguished by Miller, as follows : — C. arti-
culata, semiarticulata, inarticulate, and coadunata. The classification of Johannes
Miiller, in 1841, was based upon a number of differential characters, such as
the articular or close suture of the radials, the thickness of the calyx plates, the
mobility of the arms, and the plated or coriaceous character of the ventral disk.
Two principal groups were recognised : Articulata and Tesselata ; while a third
(Costata) was constructed for the reception of the unique genus Saccocoma.
T. and T. Austin and F. Roemer adopted the untenable divisions of Stalked
and Unstalked Crinoids.

The importance of Wachsmuth and Springer's investigations on the structure
of the calyx, especially of the tegmen, and on the orientation of the stem and
its canals in monocyclic and dicyclic forms, cannot be overestimated. Two
groups were put forward in their classification of 1879: Palaeocrinoidea and
Stomatocrinoidea ( = Neocrinoidea, Carpenter) ; groups which correspond in the
main with the Tesselata and Articulata of Johannes Miiller. This classification
was subsequently abandoned, and a new one proposed for it in 1888, in
which four principal orders were recognised, as follows : Camerata, Inadunata,
Articulata, and Canaliculata ; the latter being nearly identical with the
Articulata of Miiller. The Inadunata are further divided into the two sub-
orders—/, larviformia and I. fistulata ; but it is preferable to regard these groups

1 [Some of the Ichthyocrinidae are almost identical, in fact, with the pedunculate stages of
Antedon. Wachsmuth and Springer, from their observations on the orientation of the stem and its
canal in fossil monocyJic and dicyclic Crinoids, were led to infer the presence of infrabasals in the
nepionic or adult stages of many forms previously supposed to be without them. This prediction
was abundantly confirmed by Mr. Bury's discovery of minute infrabasals in the gastrula larva of
Antedon. See especially //. Bury, Early Stages in the Development of Antedon rosaceus, Philos
Trans, vol. CLXXIX. pp. 257-301, 1889.— TUANS.]

CLASS i CRINOIDEA 133

as of equal value with the remaining orders. The divisions established by
Wachsniiith and Springer are on the whole extremely well founded, and have
been adopted as the basis of the following systematic arrangement. The term
Inuiliiinitn is dropped, however, on raising the Larrifnrinm and Fistulata to the
rank of independent orders ; and for the terms Articulata and Canaliculatn, the
designations Flexibilia and Arlii-nlnttt are substituted respectively.

[More recently an improved classification has been prepared by Wachsmuth and
Sprin-.-r, in connection with their as yet unpublished monograph on the Crinoidea
( 'um.-rata of North America. The primary divisions of the Crinoidea as now recognised
by these authors are shown in the subjoined table.

Within tin- last few years, also, the terminology has been amended in several
important respects ; and conformably to the usage of the leading English and
Ameriran authorities, certain of these changes have been adopted in the present
r.lition. Aii explanatory note on the use of terms is therefore given at this place, in
order to facilitate reference, and to exhibit the correspondence between the older
terminology and the new.

. The only abbreviations employed in the text are the following : —

IB = Infrabasals. Br = Brachials.

£ = Basals. RA = lUdianal.

fi = Radials. IRA = First or special anal.

In addition to these the following are used in the figures, but are printed in small
letters : —

K= Calyx. 0 = Orals.

IR = Interradials.

Explanation of Terms.

= Crinoid minus the stem.
/'• = Crinoid skeleton minus the stem and free arms.
' ,-i/ji- All parts of the calyx below the origin of the free arms.

n That part of the calyx lying above the origin of the free arms, and embracing the
disk ambulacra, the mouth, and the anus. Includes the terms ventral disk, vault, dome,
in a i HI it, etc.

-Z?ose = Tliat part of the dorsal cup lying next to the column. It may be composed of one or
of two rings of plates, which are distinguished as basals and infrctbasals. The basals adjoin
the radials and alternate with them, being interradial in position. The infrabasals, when

t, form the proximal ring, and are radially disposed.

A',////,//.-,- = The circlet formed by the first plate in each of the rays ; or, the radially situated
circlet of plates above basals, and this ring only. In some of the earlier Crinoids one or more
of the radials are transversely bisected, in which case the two parts are distinguished as super -
inferradial. (Abbreviated Ji1 in the figures.)

ilx — All plates beyond the radials in radial succession. They are called faced
brachials so far as they take part in the calyx ; free brachials or arm-plates when they do not.
The brachials forming the first circlet above the radials, whether free or fixed, are called
///•///////•// hrachials, or cost(ils_ ; those of the second order distichals, or secondary brachials ; those
of the third order pal mars ; and all succeeding brachials, whether there are additional divisions
in the ray or not, receive the name post-palmars.

/i/f< r/adials = All plates occupying the spaces between the rays proper, whether they belong
to the dorsal cup or the ventral disk. Those of the dorsal cup, which are interposed between
the brachials, are distinguished as interbrachials, and those of the tegmen, which lie between
the ambulacra, as interambulacrals.

Anals= Interradials of the posterior side, forming the base of the anal structure. The special
or first anal plate, when present, invariably rests upon the truncated upper face of the posterior
basal, and between the radials. Higher anal plates may be present, even when the special
anal is wanting ; they are interposed between the interbrachials following the median line of
the posterior area.

134 ECHIXODERMATA— PELMATOZOA SUB-KINGDOM in

The Radiuiidl (= first or lower anal plate auct. ), when present, rests within the re-entrant
angle of two adjoining basals to the right of the true anal plate, and is the lower half of a
bisected radial, which only in certain genera assumes anal functions.

Orats = Ti}ie five large interradial plates which surround the mouth or cover it. They are
said to be symmetrical when of nearly the same size and form ; asymmetrical when the posterior
plate is pushed in between the four others.

Ambulacrals = r£l\z rows of small plates in the tegmen which are radially situated. They
consist of adambidacrals or side-pieces, and the covering-plates (SaumplattcJien). The former,
when present, constitute the outer, the latter the inner rows of plates. The covering plates
form a roof over the food-grooves ; they are generally represented by two alternating rows of
small plates, more or less regular in their arrangement, which are movable upon the arms and
pinnules, but upon the disk only in those Crinoids in which the mouth is exposed.

The orientation is based upon the natural position of the Crinoid, with the arms uppermost,
and viewing the specimen from the anal side. The anal interradius will then be posterior, the
radius opposite to it anterior, while the right and left sides correspond with right and left of
the observer.

Primary Divisions of the Crinoidea, according to W. and Sp.

I.

Crinoids in which the arms are free above the radials. The topmost joint the
youngest in the stem. — Order 1. INADUNATA.

(a) Disk composed of orals only. Ambulacra subtegminal. — Sub-Order A. Larviformia.

(b) Posterior side of the disk extended into a sac. Ambulacra supra tegminal. — Sub-Order

B. Fistulata.

II.

Crinoids in which the lower brachials take part in the dorsal cup. All plates of
the calyx united by close sutures. Mouth and food-grooves closed. The top joint
the youngest in the stem. — Order 2. CAMERATA.

III.

Crinoids in which the lower brachials are incorporated into the calyx either by
lateral union with each other, or by means of a skin studded with calcareous particles.
All plates from the radials up movable. Mouth and food-grooves exposed. The top
stem joint fused with the infrabasals, and not the youngest joint of the stem. — -Order 3.
ARTICULATA.

(a) Arms non-pinnulate. — Sub-Order A. Impinnata.

(b) Arms pinnulate.— Sub-Order B. Pinnata.]

Order 1. LARVIFORMIA. Wachsmuth and Springer.

(Haplocrinacea, Neumayr.)

Tegmen formed by five triangular orals only, arranged in the form of a pyramid.
Dorsal cup composed of basals and radials exclusively, except in the Cupressocrinidae,
where the basals enclose a central undivided plate. All plates immovably united by
close sutures ; arms feebly developed. Ordovician to Carboniferous.

Mostly small forms exhibiting embryonic characters persistently throughout
life.

Family 1. Haplocrinidae. Roemer.

Calyx small, pyriform to globose. Three of the radials compound, the others simple.
Orals large, triangular to pentagonal, laterally in contact. Arms jive, uniserial, non-
pinnulate. Devonian.

CRINOIDEA— LARVIFOKMIA

//.ifi/o'-riini*. Steining. (Fig. IM). I! five, // five, unequal. Three of the
radials composed of two pieces, of which
the uppenim-t oi- *njii-rr<nliii/ is the
larger, and bears an articular facet l<n-
the attachment of the arms. Anns
small, simple, uniserial, resting within
deep grooves formed along the side- ot
tlie orals. Orals large, pentagonal, and
laterally in contact ; the posterior one ^
pierced by a small anal opening. Mouth
subtegminal ; column composed of thin
joints. Not uncommon in the Middle
Devoni-m of the Eifel and Nassau- //•»/•/'"•/•;,///.•< /-«>/,;/;///•»!»'.-•, Goldf. Devonian;

,> GerolstHn, Kif.-l. O, Calyx SP.MI from on,, Bide!

<par<e in the Upper Devonian OI North b, Seen from above ; c, Seen from bdow ; A Dtaaram

4r . . of calyx ; h, Basals; ,/,tlm three tinsymmetrical plates

America. situated between basals and radials; r, Radials;

br, First arm-ossicle ; o, Orals.

Family -2. Allagecrinidae. Etheridge and Carpenter.

/; t'fi/i/.i- m-y *innlL Basak fire, md'uils Jit'e, of irregular form

i and size. Some of the radials axillary and supporting two arms ;
a other* truncate and supporting but one arm ; their articular facets
l>r<>rided with, transverse ridges and large muscle plates. Upper
Sub-Carboniferous ; Europe and North America.

.ll/it'tpcrinus, E. and C. B completely anchylosed in the
adult, and the suture lines between the orals also disappear-
ing with age. Stem largest next to the calyx, rapidly
tapering downward. Sub-Carboniferous ; Great Britain and
North America.

Family 3. Pisocrinidae. Angelin.

Cnft/.i- twwll, globose or cup-shaped, and composed of heavy
fi/ufcs. Busals three to five, radials five, very unequal, the right
posterior "in1 rmnpound. Inferradial completely roofed over by
flif literal flanges of the wjicmidHtl and right antero -lateral
f>n/i"/. .-I mi* MIH/I/C, nniseridl, and composed of long, (•/////////•/••/// '
Silurian and Devonian.

rixnc.fi HUS, de Kon. (Fig. 237, A). B five, unequal,
forming a triangle. Only the large anterior radial, and the
left posterior resting upon the basals ; the superradial of the
right posterior ray, and the right antero-lateral radial, being
^M'P01^''1 by the upper angle of the inferradial ; the latter
not in contact with the anal tube. Articular facets of the
'""-dials impressed between vertical partitions formed by the
hlteral margins of the plates. Tegmen rarely preserved;
but, as observed by Wachsmuth in P. pilula, consisting of

/>1 «T 11 !•!•

nve large symmetrical orals, above which rises a long,
narrow, anal tube. Arms long, and composed of extremely

elongate, heavy, cylindrical ossicles. Silurian ; Gottland, Dudley, England, and

North America (Niagara Group).

136

ECHINODERMATA— PELMATOZOA

SUB-KINGDOM III

Triacnnus, Miinst. (Fig. 237, B}. Differs from the preceding in having but
three B. Wachsmuth has shown, however, that some of the Eifel specimens
occasionally have five B, thus leading to the inference that the two forms are
identical. Devonian ; Eifel, Fichtelgebirge.

Family 4. Symbathocrinidae. Wachsmuth and Springer.

Calyx small, bowl-shaped, composed of three unequal or of Jive equal basals, and Jive
nearly equal radials. Tegmen foi'med by five small, asymmetrical orals ; between these
and the radials extends a long, anal tube, which, however, is not supported by anal
plates. Entire upper edges of the radials bevelled off so as to form straight articular
facets, which are furnished with well-developed transverse ridges. Arms five, simple ;
column round. Devonian and Carboniferous.

Symbathocrinus, Phill. B three, unequal ; R five, long, quadrangular or
pentagonal. The posterior oral larger than the others. Anal tube long, very
slender, resting partly upon the radials and partly upon the orals. Arms long,
uniserial, and composed of comparatively thick ossicles with sharp angular edges.
Carboniferous ; Great Britain and North America.

Phimocrinus, Schultze. Differs from the preceding in having five B. De-
vonian ; Europe.

Stylocrinus, Sandb. Distinguished from Symbathocrinus mainly by the

character of the radial facets,
which are directed obliquely
downward and inward, in-
stead of upward and outward.
Devonian.

Storting ocrinus, Schultze.
Devonian. Lageniocrinus, de
Kon. Carboniferous.

Family 5. Cupressocrinidae.
d'Orbigny.

Calyx large, basin - shaped,
composed of five equal basals and
Jive equal radials ; the basals en-
closing a central pentagonal plate,
which in all probability represents
Jive anchylosed infrabasals. Upper
faces of radials broad, truncate y
and forming an even horizontal
line. Costal s compressed, flange-
shaped. A peculiar annular

showing well- preserved ' inrolled pinnules, plated covering of structure, the SO-Cttlled " COnSOlidat-

ambulacral furrows, and neuro-vascular canals perforating the .

ossicles ; e, Interior of calyx from above, showing the five con- ing apparatus, Situated OU lite
volidating plates; the lowermost containing the anal opening- • , /• n 7

/, Radial pierced by ambulacral opening, but with wall covering, UPP^' interior margin OJ me Ctt/yj'

the same partly broken away ; 0, Side-view of radial in which the bffwffn HIP nvrn hnw<i Arm*

ring-like covering of the ambulacral opening is preserved intact. mn tfl6 a1 m ~ 0aSeS- A 1 MS

five, simple, uniserial, and closely

folded ; they are composed of broad thick plates united by close sutures, and are
traversed by a well-developed dorsal canal Column pierced by a large axial and
three, four, or five peripheral canals. Devonian.

FIG> 238.

Cupressocrinus crassus, Goldf. Devonian; Gerolstein, Eifel.
a, Perfect specimen, natural size; 1), Cross-section of column ;
c, Centrodorsal plate; d, Section through the folded -up arms,

ORDER ii CRINOIDEA— CAMERATA 137

Cupressocrinus, Goldf. (Fig. 238). Tegmen very small; the greater part of
the ventral surface covered by the so-called consolidating apparatus. This is
composed of five petaloid, horizontally truncated interradial pieces, which are
laterally in contact, and enclose a large, central open space. The opening was
probably covered by orals, as in Symbathocrinus ; while the consolidating plates
served for the attachment of muscles. Five round apertures, through which the
ambulacra entered the calyx, perforate the divisions between the consolidating
plates ; one of the latter is pierced by the anal opening (Fig. 238, «). Arms
provided with a wide and deep ventral furrow, lined on both sides with jointed,
closely abutting appendages ; of these there are several to each arm-plate, thus
showing that they are different from true pinnules. Middle Devonian ; Eifel,
Harz, Nassau, and Westphalia. C. crassus, elongatus, abbreviatus, Goldf.

Mf/rtillocnnus, Sandb. Calyx deep ; tegmen formed by five large symmetri-
cal orals resting directly upon the radials. IB fused into a single plate, and
pierced by the quadripartite canal of the stem. Devonian.

Family 6. Stephanocrinidae. Wachsmuth and Springer.

Calyx cup-shaped, composed of three elongate basals, five radials, and five inter-
radials. Radials deeply forked ; the prongs formed by the margins of two contiguous
radials extending upward between the arms, and building together with the interradials
a row of pyramids. Radial incisions occupied by the ambulacral grooves, which are
roofed over by two rows of covering pieces ; those of
the same row closely anchylosed. First costals semi-
lunate, and resting within a horseshoe-like concavity
near the outer end of radial incisions. Tegmen
constituted of five large triangular orals. Arms
very short, composed of about ten pieces, all of which
are axillary, and give off side arms. The latter are
biserial, non-pinnulate, and are made up of long,
strongly cuneiform joints. Ordovician and Silurian. no 239

Stephanocrinus, Conrad (Rhombifera, Barr.), stephnnocrinus anguiat-us, Conrad, sii-
(Fig. 239). This unique genus is distinguished Of S^°nKi ST^BunTmif £££
from all other Larvifwmia by the biserial and ^SLk^a^aftSnaU)?" °f the
branching character of the arms, as well as by

the presence of small interradials. Anal aperture situated near the summit of
one of the interradial projections. Ordovician (Etage D) ; Bohemia. Silurian ;
North America.

Order 2. CAMERATA. Wachsmuth and Springer.

(Sphaeroidocrinacea, Neumayr. )

The lower arm-plates incorporated into the dorsal cup by means of supplementary
plates. All plates of the calyx united by close sutures, and immovable. Tegmen in
the form of a solid vault, composed of rigidly united plates. Mouth- and food-grooves
completely covered; the covering pieces of the latter frequently incorpoi'ated in the
tegmen. Anal opening eccentric or subcentral, frequently situated at the end of a
proboscis-like anal tube. Interradials constantly present in all interrays ; inter-

1 38 ECHINODERMATA — PELMATOZOA SUB-KINGDOM in

dislirhdl* «n<l inki-pnlmurs often, and in most cases anals also present. Arms
uniserial or Userial, and pinnulate. Ordovician to Carboniferous.

[Analysis of Families, according to Wachsmuth and Springer.1

I.

Lower brachials and interbrachials forming an important part of the dorsal
cup.

A. — INTERRADIALS ILL-DEFINED.

The lower plates of the rays more or less completely separated from those of other
rays, and from the primary interradials, by irregular supplementary pieces. Anal
interradius divided by a row of conspicuous plates. Dicyclic or monocyclic. —
RETEOCRINIDAE.

B. — INTERRADIALS WELL-DEFINED.

1. Dicyclic—

(a) Radials in contact except at the posterior side. — THYSANOCRINIDAE.

(b) liadiah separated all around. — RHOPOCRIXIPAE.

2. Monocyclic —

(n) Jtit'fiitlfi iii contact all around.

Symmetry of the dorsal cup, if not strictly peutamerous, disturbed by the introduction

of anals between the brachials only. — MELOCRINIDAE.
Arms borne in compartments formed by partitions attached to the tegmen. Dorsal cup

perfectly pentamerous. Calyx plates limited to a definite number. — CALYPTOCRINIDAE.

(b) Radials in contact except at tlie posterior side, where they are separated by an anal plate.
First anal plate heptagonal, followed by a second between two interbrachials. — BATO-

CRINIDAE.

First anal plate hexagonal, followed by two interbrachials without a second anal. Arms
branching from two main trunks by alternate bifurcation. — ACTINOCRINIDAE.

II.

Brachials and interbrachials but slightly represented in the dorsal cup.

1. Dicyclic —

Radials in contact except at the posterior side. — CROTALOCRINIDAE.

2. Monocyclic —

(a) Radials in contact all around. Base pentagonal. — PLATYCRIXIDAE.

(b) Radials separated at the posterior side by an anal plate. Base hexagon*/.

Basals followed directly by the radials. — HEXACRINIDAE.

Basals separated from radials by accessory pieces. — AcROCRINIDAE.]

Family 1. Platycrinidae. Roemer.

Dorsal cup composed of a monocyclic base and a circlet of five large radials,
without special anal plate. The lower brachials, which form part of the calyx, similar
in form and size to tlie free arm- joints. Interradials heavy, restricted almost
exclusively to the tegmen ; only those of the first row to a certain extent interbrachial.
Arms often numerous, generally free from the distichals upwards; uniserial or
Userial. Pinnules well developed. Silurian to Carboniferous.

1 [ Wachsmuth, C., and Springer, F. The Crinoidea Camerata of North America (Memoirs
Museum Comp. Zool. vol. xxiv.) In press. The above is extracted from proof-sheets kindly
furnished by the authors. — TllANS.]

OKPKR ii ( 'HIXOIDEA— CAMERATA I 3!>

Platycrinus, Miller (Figs. 229, 240). />' three, unsymmetnYal, fiv.jiiently
anchylosed. /,' long, large, laterally unitpd by close sutures, and furnished
siippi-inrly with a crescent- shaped articular facet. Succeeding the R, and
united with them by close sutures, is a row of small axillaries. These are.
often so minute as to be completely hidden within the
radial facets, as is also the case sometimes with the first
distichals. First row of interradials on a level with the
arm-bases, ,ind consisting of three plates horizontally
arranged; they are in part interbrachial and in part
interambulacral. The higher interradials, when present,
strictly interainlmlaeral ; plates of the anal interray more
numerous than those of the four regular sides. Orals
large, asymmetrical, and resting against the interradials.
Covering pieces of the ambulacra generally exposed, very
rigid, and incorporated into the tegmen. Anus either
eccentric, or placed at the end of a short thick tube.
Arms uniserial at their lower ends, but gradually becom-
ing biserial. Column elliptical and twisted; the axes of

'O . , . . , I'lutHn-tHiisti-Hjiiitidin-tHl'i*,

the upper and lower surfaces of the individual segments Austin sp. Carboniferous
1 icing slightly shifted upon one another. The stem is (reTtor^d'aiJe^de^oSrick""1
pierced by a very minute axial canal, and gives off cirri

toward the distal end. Extremely scarce in Devonian, but abundant in Carbon-
iferous. P. laevis, Mill. ; P. hemisphaericus, M. and W.

Eudadocrinus, Meek. Calyx and stem as in Platycrinus, but having the
rays produced laterally into large tubular appendages, from which biserial,
pinnule-bearing arms are given off alternately throughout their entire length.
Sub-Carboniferous (Burlington and Keokuk Groups).

Coccocrinus, Miiller (Fig. 227). Like Platycrinus, but the costals wider,
and forming together with the interradials a part of the dorsal cup. Costals
two, succeeded by two distichals, of which the upper one is axillary; inter-
radials only one to each side. Orals large, triangular, abutting against the
interradials, and forming nearly the whole of the ventral surface. They are
separated from one another by a deep angular groove, closed at the bottom.
Anal opening in the suture between the posterior interradial and its corre-
sponding oral. Silurian ; Tennessee. Devonian ; Eifel.

Culicocrinus, Miiller. Transitional between Coccocrinus arid Platycrinus.
Calyx, as in the former, small and globose ; but the orals somewhat asym-
metrical. Arms bifurcated, heavy, biserial. Column round. Middle
Devonian ; Kifel.

Cordylocrinus, Aug. Arrangement of calyx plates as in Platycrinus, but
the tegmen higher, and arms uniserial. Column round, and bearing long
cirri ; the upper ones reaching nearly to the tips of the arms. Silurian ;
Gottland.

Miirsupiocrinus, Phill. Dorsal cup depressed, saucer-shaped. B and R as
in J'latycrimis. Radials rapidly spreading, and followed by a very small
trigonal axillary ; this, together with the two superjacent distichals, is buried
within the radial facet, so that the three plates are wholly or almost wholly
supported by the radials. Tegmen composed of numerous small pieces ; anal
opening eccentric. Column round, and traversed by a large axial canal.
Silurian ; Gottland, England, and North America (Niagara Group).

140

ECHINODERMATA— PELMATOZOA

SUB-KINGDOM III

Family 2. Hexacrinidae. Wachsmuth and Springer.

Dorsal cup composed of a monocydic base, five large radials, and an anal plate
similar in farm and size to the radials interposed between them. In all other respects
constituted like the Platucrinidae. Devonian and Carboniferous.

Hexacrinus, Austin (Fig. 241). B three, equal; R five, very large and
elongate. Tegmen low, composed of relatively large plates, and pierced by an
eccentric anal opening. Arms uniserial or biserial; pinnules unusually long.
Column round. Devonian ; represented by numerous species in England,
France, Belgium, and the Eifel, but by only a few in North America.

DicJwcrinus, Miinst. Differs from Hexacrinus in having but two hexagonal
basals, and an eccentric anal opening. Sub-Carboniferous ; Belgium. Great
Britain, and North America.

Arthrocantha, Williams (Histricrinus, Hinde). Like Hexacrinus, except that
the calyx plates are beset with short mobile spines. Devonian ; North
America.

Pterotocrinus, Lyon and Cass. B two, equal. R short, rapidly spreading ;
their upper faces excavated for the reception of several orders of brachials,

FIG. 241.

Hexacrinus elongatus, Goldf. Devonian ; Pelm, Eifel. a, Calyx seen from one side ; 6, Aspect of summit ;
c, Diagram of calyx and arms ; d, e, Column of H. spinosus, Milll. (after L. Schultze). ,

which rest with their lateral edges upon it ; all of these plates taking part in
the dorsal cup. IRA less than half the size of the R, and sometimes
triangular. Tegmen highly elevated, pyramidal. Orals large, asymmetrical ;
their lower angles enclosing five large, radially disposed plates, which are
separated from one another by interambulacral pieces. These plates are
provided with enormous, leaf-like, club-shaped, or spatulate processes, which
project outward conspicuously from between the arms. Anus sub-central.
Arms four to each ray ; biserial. Kaskaskia Group ; North America.

Talarocrinus, "W. and Sp. Intermediate between the preceding and Dicho-
crinus; structure of the tegmen resembling the former, that of the dorsal cup
the latter. IRA slightly smaller than the R ; its upper • end narrower than

ORDER ii VCRINOIDEA— CAMERATA 1 4 1

the lower. Costals one to each ray, very minute, trigonal ; they are roofed
over by the distichals, which rest with their sides upon the R, but are laterally
in contact with one another. Processes of the tegmen thorn-like and less
prominent than in I'terotocrinus. Arms two to four. Anus sub-central. Con-
fined to the St. Louis Limestone of North America.

Family 3. Actinocrinidae. Roemer.

Base monocyclic. Basals three, sub-equal ; radials united laterally, except at the
posterior side, where they are separated by a large anal plate. Fixed brachials large,
xiiiiilnr in for/n fo the radials. Interradials abundantly represented ;
the first row interposed between the primary brachials, and consisting
< if a single plate in each of the interrays except the posterior ; the
second row consisting of two or three plates, and usually succeeded
by additional rows. Plates of the tegmen numerous, and forming a
rigid vault. Orals markedly asymmetrical; anus sub -central,
eccentric, or marginal, with or without an anal tube. Ordovician
to Middle Sub-Carboniferous.

[The Actinocrinidae, Roemer, according to "Wachsmuth and
Springer, fall naturally into two subdivisions, which are elevated
by them in their forthcoming Monograph to the rank of inde-
pendent families. The relations between the two sections, which
are designated as groups A and B in the original, and the genera
embraced by them, are as follows : — Fl°- 242-

Patelliocrinus lepio-

A. (ACTINOCRINIDAE, s. str.), IRA hexagonal, succeeded by two gSSrian; ^Sfttiand'.
interbrachials without a second anal. (Actinocrinus, Cactocrinus, ^Jjjj™* size (after
Amphoracrinus, Teleiocrinus, Steganocrinus, Physetocrinus, Strotocrinus.}

B. (BATOCRINIDAE, W. and Sp.), IRA heptagonal, succeeded by two interbrachials
which enclose a secondary anal. (Batocrinus, Eretmocrinus, Dorycrinus, Agaricocrinus,
Alloprosalocrinus, Barrandeocrinus, Habrocrinus, Desmidocrinus, Periechocrinus, Megisto-
crinus, Abacocrinus, etc.]

(SECTION A.) ACTINOCRINIDAE.

Actinowinus, Miller (Fig. 243). Calyx pyriform or ovate; plates of the
dorsal cup generally ornamented with striae passing from plate to plate. B three,
equal, forming a hexagon. Three of the R six-sided, generally higher than
wide ; the posterior pair heptagonal. First costals nearly as high as wide ;
second costals axillary, supporting both distichals and palmars, and frequently
higher orders of brachials. IR very numerous, passing insensibly into the
tegmen ; anus sub-central, and borne at the end of a large, strong anal. tube.
Arms biserial ; not bifurcating in their free state, or rarely so ; and given off
in clusters from lateral expansions of the calyx. Pinnules long, slender, and
laterally in contact. Column long, round ; its joints frequently sharply edged,
and with striated upper and lower faces. Abundant in Sub-Carboniferous of
North America and Europe.

Cactocrinus, W. and Sp. Like the preceding, except that the arms form a
continuous ring around the calyx, and the IR of the dorsal cup are separated
from those of the tegmen. Sub-Carboniferous ; North America.

Amphoracrinus, Austin. Dorsal cup, saucer-shaped or almost flat; tegmen

14-2

K< ' H ! X< > I > K 1 ! M ATA— PELMATOZOA

SUB-KINGDOM III

highly elevated. Arms heavy ; branching in the free state. Anus borne at

FIG. :>43.

A, Actlnwriniix y/;W»,M •/<//«//.<, Hall. Hub-Carboniferous; Burlington, Iowa. Calyx with fractured tegmen,
showing the subtegininal anibulacral skeleton, and the convoluted digestive organ. K, Diagram of Dorycrinvs.
C, Natural cast of tegmen of Physetocrinus, with impressions of food-grooves (a), conducting from the arms to
the mouth (o) ; an, Anus. D, Enlarged portion of the anibulacral skeleton (after Meek and Worthen).

the end of a short, stout, spinous tube. Lower Sub-Carboniferous ; North
America and Europe.

Teleiocrinus, W. and Sp. Arms closely crowded, and forming a broad con-
tinuous flanging rim around the calyx. Anus at the
upper end of a long tube. Upper Burlington Limestone.
Steganocrinus, Meek and Worth. Burlington Lime-
stone.

Physetocrinus, M. and "W". Arms crowded ; the arm-
bases projecting in a rim, which is interrupted along the
interrays. Anus in the form of a circular opening
through the tegmen. Lower Sub-Carboniferous ; North
America, England, and Belgium.

Strotocrinus, M. and "VV. Arms crowded ; the upper
part of the dorsal cup produced in an immense rim,
which is horizontally directed, and is composed of higher
orders of brachials. Tegmen flat ; composed of innumer-
able minute pieces. Anus in the form of an opening
through the tegmen. Restricted to the Upper Burlington
Limestone.

(SECTION B.) BATOCRINIDAE.

Batocrinus, Gassed. (Fig. 244). Similar in form to
Actinocrinus, but calyx plates without sculpturing.
R hexagonal or heptagonal. First costals quadrangular,
always shorter than the Pi, and transversely arranged.
IRA ^ the same size as the 11 Interradials rarely more
t*uul tnree> an(* arched over by the palmars and higher
bnichials, when these are present in the calyx, so as to
be completely shut off from the plates of the tegmen. Tegmen elevated ; its

OUDKIt If

CR1NOIDEA— CAMERATA

143

plates heavv, and more or less turbid. Anal tube nearly central, very long, and
gradually tapering. Anns simple, hiserial, and very short. Confined to the
Sub-Carbonifflroufl of North America. Type — B. icosidactylus, Gassed.

Erehnocrinuttf Lvon and Cassed. Like the preceding, but the Hi of the
dorsal dip (••.minimus \\ith tho-e «.f tin- teamen, and arms nearly twice as long:
their upper portions much wider, spatulate, and folded inward. Anal tube
shorter than in /A/Awy/'// */.-•, and <.ften Kent abruptly to one side. Sub-Carboni-
ferous; North America.

/A//-//OV////S, Uoem. ( Fi-. L'45). Calyx broadly turbinate or sub-globose,
truncate at the base, and deeply -innate in all the interradial areas, but chiefly
so in the posterior one. Hates of the dorsal cup smooth or corrugated, but not
Mriated, and all more or less convex. Tegmen strongly convex, composed of
moderately heavy plates. Orals five, large ; the posterior one nodose, or more
frequently extended into a long spine, and occupying a central position.
Surrounding these and overlying the ambulacra are five other spinous or nodose,
plates, which are separated by interradial pieces. Anus lateral in position, and

FIG. 24.").

1/1/1 inii/i'/nhiix, Hall, VHI'.

InterSMdlu*. M.and W. Sub-Carbon-
iferous ; Burlington, Iowa. Calyx
viewed from tin- anal side. Natural
sizt- (after Mrrk ami Wortlien).

FIG. -240.

a, IIal>i'<H-i-!iiiix <•<>!, tt us. Aug. .Silurian ; (iottland.
Tegmen viewed from the anal side. Natural size ;
I, H. ortHitus, Aug. Tegmen showing cnveriii"
pieces of the ambulacra (after Angelin).

not extended into a tube. Arm openings twelve to twenty; the arm-bearing
plates protuberant. Devonian ; Eifel. Lower Sub-Carboniferous ; North
America.

Agaricocrinus, Troost (Fig. 231). Calyx much depressed ; basal disk flat or
slightly concave. 11 supporting two primary £r, which are followed by short
distichals, and in rays with more than two arms, by still shorter palmars. lit
of the dorsal cup rarely more than four ; those of the tegmen numerous, especially
at the anal side. Tegmen high, pyramidal ; the upper end occupied by a
massive, button-shaped, central piece, which is surrounded by four similar, but
slightly smaller plates ; these constituting together the orals. Confined to the
Sub-Carboniferoua of North America. A. Americanus. Eoem. sp. ; A. pentuqonu*
Hall.

Alhproaalocrinia, Lyon and Cass. Warsaw Limestone.

Habrocrinus, Ang. (Pionocrinus, Aug. ; Carpocrinus, Mull.), (Fig. 246). JJ three,
equal. Costals 2x5; the distichals supporting the arms. IRA very large,
and followed by numerous IE, arranged in rows of two or three plates. Arms
uniserial, long, heavy, and simple throughout. Silurian ; Gottland and England.

144

ECHINODERMATA— PELMATOZOA

SUB-KINGDOM III

[The genus Carpocrinus was described by Miiller as having no anal plate ;
but according to Angelin the type-species (C. simplex) has an IRA interposed
between the radials. It must therefore be referred to Habro-
crinus, which it resembles in all other respects.]

Desmidocrinus, Ang. (Fig. 247). Like the preceding, but
with a greater number of arms, which are longer, and composed
of shorter joints. Silurian ; Gottland.

Periechocrinus, Austin (Geocrinus, d'Orb.) Calyx large, elon-
gate, somewhat urn-shaped, and composed of thin plates. R and
primary Br long and narrow, frequently bearing a median longi-
tudinal ridge. Distichals two ; interradials very numerous, the
second row composed of either two or three plates. Plates of
the tegmen very small. Anal opening sub-central, sometimes
prolonged in a tube composed of small, thin plates. Arms
numerous, slender, branching, biserial ; pinnules long and thin.
Column round, pierced by an extremely large axial canal.
Silurian ; Gottland, England, North America.

Megistocrinus, Owen and Shum. Devonian to Middle Sub-
Carboniferous ; North America. Abacocrinus, Ang. Silurian ;

Desmidocrinus
heterodactylus, Ang.
Silurian ; Gottlanc

AnS).siz' r Europe. Gennaeocrinus, W.
Group) ; North America.

and Sp. Devonian (Hamilton

Family 4. Barrandeocrinidae. Angelin.

Base monocydic. Basals three, enclosing an anal plate which supports three inter-
Arms biserial, recumbent ; pinnules, exposed, and directed upwards. Silu-
rian ; Gottland.

Barrandeocrinus, Ang. R followed by two costals ; the upper ones giving off
two heavy arms, which in perfect specimens are so closely folded as to conceal
the calyx completely. Pinnules very long; their tips bending inward from
opposite sides. Column cylindrical, and very heavy ; axial canal circular.
Silurian ; Gottland.

[This genus is referred by Wachsmuth and Springer to the Batocrinidae
and the family discontinued.]

Family 5. Reteocrinidae. Wachsmuth and Springer.

Monocydic or diet/die. Infrabasals, when present, five ; basals four to Jive. Radials
separated by a large IRA which supports a vertical row of higher anals all of nearly
the same size • the upper ones passing gradually into the tegmen. The spaces to either
side of this row, as well as the whole of the four other interrays, both in the dorsal cup
and tegmen, paved with minute, irregularly formed pieces. Ordovician.

Reteocrinus, Bill. Calyx obconical ; interradial and interaxillary areas
profoundly depressed. IB five, differing considerably in size. B five, large, pro-
tuberant, hexagonal. R and fixed brachials forming a broad, highly elevated
ridge, which passes insensibly into the arms. IE in contact with the B, and
consisting of a large number of minute, irregular pieces. Tegmen composed of
numerous, very small, convex plates, irregularly arranged. Arms with strong
pinnules, and branching in the free state. Column sub-pentagonal. Ordovician ;
North America.

< KINOIDEA— CAMKRATA 145

Xe*ocrm**i S. A. Miller. IB obsolete; B four; (-(,11111111 Muadran«,'ular.
< Hli<T\\ isc ivst-mbling /,V/"/ov'////s. ( )rdovician ; North America.

Family 0. Thysanocrinidae. AYarli-mutli and Springer.

(d/it/.fni-riii'nlai; pp. Zittel ; (///////».</>• /-/W,,s Angelin.)

AW- ,//>//,-//>. 7,'<"//Vx /,/A-/W/// /// confo4 casegrf "/ ///'- interior side, where they
are sep«r<i1<'<l lij mi a, ml ji/afr. Thi* in follmwd !>// wwrnl rows o/ interradials,
between which additional tum/.< or» inf, rj>o«ed. Ordovician and Silurian.

[Thysanocrinidae was substituted by W. and Sp. as a family name, on dis-
covering the identity between </////</</.»•/<•/•, /iiutrrm-riiius, Eucrinus, and Thysano-
crinus. The last-named genus is entitled to priority, from being the first to
have received a tolerably accurate description. Glyptocrinus, Hall, and Stelidio-
cr'mus, Ang., are removed to the MelocrinidaeJ]

ThiiHuun'iiiitix, Hall (Glyptaster, Hall; Dimerocrinus, Phill. ; Eucrinus, Ang.)
Calyx deep. IRA followed by three plates. Arms ten to twenty, biserial.
Silurian (Niagara Group) ; North America, England, Gottland.

JIf//)tiocrinust W. and Sp. Dorsal cup saucer-shaped, almost flat ; the larger
plates of the tegmen spiniferous. Arms pendent. Niagara Group ; North
America.

Ptyclwcrinus, W. and Sp. Like Thysanocrinits, but arms uniserial. Ordovician ;
North America.

Idiocrinus, W. and Sp. IR represented by a single large interbrachial in
each of the interrays ; that of the posterior side resting upon IRA. Niagara
Group ; North America.

Spyridiocrinus, Oehlert. Devonian ; Saint Malo, France.

Lampterocrinus, Roem. Like Thysanocrinus, but having an anal tube ; IE A
large, and succeeded by three longitudinal rows of IR. Silurian (Niagara
Group) ; North America.

Orthocrinus, Jaekcl. Devonian ; Rhineland.

Family 7. Rhodocrinidae. Eoemer.

Base dicyclic. Infnibasals five ; lasals five, pentagonal, truncated at the upper end.
The radials separated all around by large interradials. Anal area but very slightly,
often not at all different from those of the other interrays. The rays generally free
above the disticlials ; primari/ urutx rarely more than ten, and either simple or branching.
Pinnules long and closely abutting. Ordovician to Sub-Carboniferous.

Rhodocrinus, Miller (Acanthocrinus, Roem.) Calyx small, composed of delicate
plates. IB frequently hidden by the column. B and IR large ; the latter
rapidly decreasing in size upward. Rays free from the distichals upward, and
the ten primary arms branching once or oftener in the free state. Arms biserial,
thin, and moderately short; pinnules closely crowded, long, and slender. Column
round ; axial canal stelliform. Ordovician to Middle Sub-Carboniferous ; Europe
and North America.

Archaeocrinus, W. and Sp. Calyx obovate. IR numerous, and enclosing
a supplementary anal in the second or third row. Interdistichals generally
present. Arms uniserial, branching. Ordovician ; Canada.

RhaphanocrinuSy W. and Sp. Like the preceding, but with large IB,
which are exposed in a side view. Arms long, simple, and uniserial. Ordo-
vician ; Ohio and Indiana.

VOL. I L

146

ECHIXODERMATA— PELMATOZOA

SUB-KINGDOM III

Cumberl. (Gilbertsowinus, Phill. ; Goniasteroidocrinus, Lyon and
Gassed.) Agreeing with Rhodocrinus in the structure of the calyx below the
arms, but readily distinguished by the so-called pseudobrachial appendages,

and by the size and disposi-
tion of the arms. Above
each distichal is a round
ambulacra! opening (ten in
all), through which the am-
bulacra of the arms conduct
into the calyx. From above
each of these openings spring
two tufts of small, branching,
pinnule-bearing arms. These
are either folded over the
tegmen, or they bend down-
wards with the ventral side
exposed to view, the pinnules
being directed upwards. Ten
tubular appendages extend
outwards and downwards
from the upper margin of
the calyx. In the American
species these are united later-
ally in pairs for some dis-
tance ; but in the European
ones they are separated. One species in the Hamilton Group of New York ;
the remainder Sub-Carboniferous ; North America and Europe.

Lyriocrinus, Hall. Calyx depressed ; plates smooth or finely granulose.
Tegmen almost flat, composed of a large number of small plates. Anus
eccentric; not extended in an anal tube. Arms ten, strong, simple, biserial.
Confined to the Niagara Group of North America.

Rhipidocrinus, Beyrich (Fig. 248). Calyx cup- or urn-shaped, with a more
or less flattened or concave base. Plates of the dorsal cup heavy, and highly
ornamented. IB five, small, forming a pentagon. B five, equal ; R and
axillary costals pentagonal. First IR large, heptagonal. Tegmen low, com-
posed of an immense number of small thick plates, irregular in their arrange-
ment ; anus eccentric. Arms given off from calycular appendages, and
composed of wide transverse pieces, which bear at intervals on alternate sides
biserial, pinnule-bearing armlets. Column round, heavy ; axial canal pentalo-
bate. R. crenatus, Goldf. sp. Middle Devonian ; Eifel.

Thylacocrinus, Oehlert. Resembling Lyriocrinus, but the calyx more elongate.
IR and interdistichals profusely developed. Arms numerous, heavy, biserial,
not branching in the free state. Devonian ; France and North America.
Dumenocriwus, Oehlert. Devonian ; Manche (France) and Germany.

FIG. 248.

]Hi!jiiilui 'riiius crenutus, Goldf. sp. Devonian; Gerolstein, Eifel.
A, Perfect crown, of the natural size (after Scliultze). B, Tegmen,
with eccentric anus. C, Interior view of the base, showing the live
II'.. two of the L', and one R. I), Column. E, Face of stein-joint.

Family 8. Melocrinidae. Zittel (emend. W. and Sp.)

Base monocydic. Basals three to five ; radials laterally in contact, not
an anal plate. Interbrachials frequently separated ly supplementary amis. Ordo-
vician to Devonian.

CUINOIDKA— CA.MKIIATA

147

Melocrinu$, <:..ldf. (Cfciwerww*, Broun), (Fig. 249). Calyx pyriform or
melon-shaped, highly ornamented with i-adiating ridges or small nodules. li
four : /•' hexagonal ; /// numerous ; those of the posterior interray enclosing one
or more Mipplementary anals. Tegnien formed by relatively large, asym-.
metrical orals. Anal aperture eccentric, rarelv extended in a small tube.
histidials <if the sann- ray later-
ally united, either as far as the
full length of the arms, or only
for a short distance. They form
in all five free ealycular append
ages, composed of single joints.
From the outer sides of these
appendages hiserial, pinnule hear
ing arms are given oft' at intervals
in a lateral direetion. Column
round : axial canal small, round,
or obtusely pentagonal. Silurian
and Dexonian; Europe and N. A.

Tn-hnocriims, Hall. Like Melo-
ci-uni.t. but having strong, simple,
uniserial anus, which do not bifur-
eat e in the free state. Interbrach-
ials not enclosing supplementary
anals. Oriskany ; Maryland.

Murim-riiius, Hall (emend. W.
and Sp.) B four. Arms biserial,
and given off' directly from the
calyx in an oblique direction.
Surface ornamentation like Glypto-
crinus ; otherwise resembling Melocrinus. Silurian ; Europe and North America.

('ni-iiinliin;-iiiuti, Ang. (Polypeltes, Aug.) Dorsal cup strictly pentamerous.
B four, forming an inverted cup, and hidden beneath the column. Interbrachials
large, not enclosing anal plates. Arms biserial, dichotomous, and closely
apposed. Silurian ; England and Gottland.

[The genus Polypdtes, Ang., is shown by Wachsmuth and Springer to have been
founded upon erroneous observations, P. yranulatus, Ang., being certainly a multi-
bruchiate tJoriiinlnH-rinn.<, in which the B and R are concealed in the inverted cup of
the base. The family Polypeltidae, which was established by Angelin for the recep-
tion of this genus, is therefore discontinued.]

Patelliocrinits, Angelin (Fig. 242). Silurian ; Gottland.

Scyphocrmus, Zenker. Calyx very large and elongate. Symmetry of dorsal
cup slightly disturbed by anals which are interposed between the interbrachials.
B four ; distichals five or more ; the lower palmars incorporated in the calyx, the
upper ones free. Interbrachials very numerous. Arms biserial, long, branch-
ing. Silurian : Bohemia.

Glyptocrimts, Hall (Fig. 250). Dorsal cup obconical to sub-globose, orna-
mented with radiating striae passing from plate to plate ; the elevations
following the rays more pronounced, and forming well-defined rounded ridges,
which meet imperceptibly with the free arm-plates. B five ; interbrachials very

Fie;. -24'.'.

Ctenoi-i-iii a* til/Hi*, Bronn. Devonian (Bplriferen-Saodatein) ;
Daun, Eifel. B, Basul.s. ( ', Mould of stem-joints (the so-called
" Schraubensteine ").

148

ECHINODERMATA— PELMATOZOA

SUB-KINGDOM III

numerous, and enclosing supplementary anals, which sometimes form a con-
tinuous series. There are also numerous interdistichals, and frequently
interpalmars, which form conspicuous depressions between the arm-plates.
Tegmen low, composed of minute irregular pieces ; anus eccentric. Arms ten
to twenty, branching in the free state, long, slender, and
uniserial. Column round, or exceptionally pentangular.
Ordovician ; North America.

Stelidiocrinus Ang. (Harmocrinus, Ang.) Form of dorsal
cup as in the preceding, but the IR fewer and much larger,
and plates generally without ornamentation. Plates of the
tegmen also comparatively large. Arms uniserial, sometimes
interlocking. Silurian ; Europe and North America.

Macrostylocrinus, Hall. B three, unequal, Anal interradius
much wider than the others ; its first row of IR consisting of
FIG "50 two interbrachials separated by a supplementary anal. The

Giyptocrinus deca- first row in the four other interrays consisting of a single
dactyius Hail. Ordo- interbrachial. Arms ten, simple, and biserial. Silurian: North

vician (Hudson River

Group) ; Cincinnati, America.

Allocrinus, W. and Sp. B three,- unequal. Interbrachials
few, longitudinally arranged. Arms uniserial. Silurian ; North America.

Dolatocrinus, Lyon (Cacabocrinus, Hall). Dorsal cup perfectly pentamer-
ous, cup -shaped or saucer -shaped. B primitively three, but completely
anchylosed in the adult. Costals two ; interbrachials few, the first ones
extremely large. Tegmen comparatively flat, and composed of rather large
plates, of which the orals form the summit. Anus at the end of a short tube.
Arms biserial ; generally branching. Devonian ; North
America.

Stereocrinus, Barris. Like the preceding, but the
anchylosis of the B incomplete, and with only one costal.
Hamilton Group ; North America.

Family 9. Calyptocrinidae. Angelin.

Base monocydic. Lower brachials and interbrachials form-
ing an important part of the dorsal cup, which is perfectly penta-
merous. Plates of the calyx limited to a definite number.
Basals four • radials five, in contact all around ; costals 2x5;
distichals two; and palmar s 2 x 10, of small size.. Arms
twenty, resting in compartments formed by partitions attached
to the tegmen. Silurian and Devonian.

Eucalyptocrinus, Goldf. (Figs. 251, 252). Calyx with a
deep concavity at the lower end, the B forming the bottom,
and the R the sides of an inverted cup. Supplementary Eucaiyptocri
pieces of the calyx consisting of 1 x 2 interbrachials, and GoSd. sp'crownl "with
one interdistichal ; the latter of the same form as the inter- ^'V^rlo Sow the
brachials, and nearly as large as the two upper ones niclies in which they
combined. Tegmen elongate, its upper part extended
to form a tube. It is composed of five ranges of plates, of which the two
middle ones are the least regular in their arrangement, and the upper one
closes the centre. Attached to the outer walls of the tegmen, and extend-

nusreyvlaris,

:HH CRINOIDEA— CAMERATA I r.»

to its t<»p. are ten partitions supported by the intcrbrachials and inter-

ii-i : ri 1-2
dist.l (list."

FIG. 252.

( ioldfuss. Devonian; Gerolstein, Eifel. A, Perfect crown. B, Diagrammatic
longitudinal section of the calyx (b, Basals ; >•!, Hadials ; r'l, First costals ; y, Lower, and 5, upper piece of the
wing-likf processes). (,', 'IVginen. J>, Dorsal cup (/•!, Radials; »•-', First costals; ir, Interradials ; <li.<t., Dis-
tichals ; Int. flint., Interbrachials, after L. Schultxe). •

distichals, which form deep, vertical compartments for the reception of two
arms each. Arms twenty, biserial ; composed of very narrow pieces. Column
round. Silurian ; Gottland,
Ki inland (Wenlock Lime-
stone), and North America
(Niagara Group). A single mf
>jiecic8 occurs in the De-
vonian of the Eifel.

fiill'ii-niniSy Aug. (Fig.
2 53). Calyx flask-shaped ;
i< >IK -a\ it vat the base deeper
and wider than in the pre-
ceding, sometimes involv-
ing not only the radials,
but parts of the costals as
well. Partitions for the

ro^rtfinii nf flin arm* nnli CWHcrtiMM n ,.-</< i his, Hising. sp. Silurian; Gottland. A, Crown.

I CCeptlOll Ot the arms mUCh B> Calvx. shl,win., th(. coBsKtlon of the tegmen. C, Inner or ventral

shorter extending tO less asPect ot the base. D, Outer or dorsal aspect of the same. Natural

i 'ir .1 1-1 c ! sixe (after Angelin).

than half the height of the

aims. Otherwise similar to Eucalyptocrinus, arid sharing the same distribution.
Hypanthocrimts, Phill.' Probably identical with Eucalyptocrinus (Fig. 251).

Family 10. Crotalocrinidae. Angelin (emend. W. and Sp.)

Base dicyclic. Dorsal cup composed of five infrabasals, five basals, five radials,
an anal plate, and the lower brachials, which are laterally in contact. Upper edges of
radials more or less excavated. Tegmen fiat or bid slightly elevated ; its plates immovably

Fio. 253.

ECHIXODERMATA— PELMATOZOA

SUB-KINGDOM III

united by sutures. Orals asymmetrical ; ambulacra bifurcating once or twice within
the calyx, and roofed by two roics of very regularly arranged covering pieces ; a few
inter ambulacrals also present. Anus eccentric, placed at the end of a tube. Arms
uniserial, dichotomising at short intervals throughout their entire length. Pinnules
unknown. Column round, strong, the distal end formed into a thick root. Silurian.

This family embraces the genera Crotalocrinus, Austin (Anthocrinus, Mtiller),
(Fig. 254), and Enallocrinus, d'Orb., both of which are found in the Silurian of
Gottland and England.

The arms of the same ray are laterally united in Crotalocrinus throughout

FIG. 254.

A, Crotalocrinus pulcher, Rising. (Anthocrinus Loveni, Miiller). Silurian ; Gottland. Crown with folded
arms. B, Portion of stem. C, Cross-section of four contiguous arm-ossicles of the network. I), Dorsal aspect
of arm-plates, showing their intimate union ; those above the two rows figured have been broken away so as to
expose the side-pieces and covering plates of the ambulacra] furrows. E, Tegmen of C. rugosits, Miller (after
Angelin).

their entire length, so as to resemble five broad, reticulate leaflets ; Avhile those
of Enallocrinus are united for a certain distance only, and then become free.
The arms in both forms were capable of being stretched out horizontally on the
same level with the tegmen.

Order 3. FISTULATA. Wachsmuth and Springer.
(Inadunata fistulata, W. and Sp. ; Cyathocrinacea, Neumayr.)

All plates of the dorsal cup united by close suture. Jtadials bisected or simple.
Anal plate (IRA) generally, and radianal (RA) frequently represented ; the former
resting upon the truncated upper face of the posterior basal, the latter situated to the
right of Die IRA, and within the angle formed by the posterior and postero-lateral
basals. Interradials proper not represented. Tegmen greatly extended at the posterior
side to form an elongate or balloon-shaped sac. Ambulacra tegminal, lined by side-
plates, and roofed over by small covering pieces. Mouth eccentric and subtegminal,

• Knr.u in

< 'K I NOIDEA— FISTULATA 151

by for. <>nik. Arms free from tlu radial* >/////v//v/ .-
,.tii>imllii /'/'s/r/W. /'i /i miles present or absent. Ordovician to Trias.

The /Y.-7//A//" an- characterised by an enormous development of the posterior
interradius, which is extended upward s<» as to form a large ventral sac or tube:
The plates of this sac are in some cases perforated by small, round, or slit-like
p<»ivs (I'l'sjiiriifiti'ii jutffa) • while in others the pores are replaced by superficial
pits. In the latter forms, a large, profusely perforated plate (madreporiti) is
interposed <>n the disk proper between the sac and the month.

The position of the anus, as observed by Wachsmuth and Springer, is at
the side of the sac nearest the mouth ; or it
pierces the disk proper between the sac and
the mouth.

The radials in some families of the Fistulata
are transversely bisected in one, two, or in three
rays. \Vhen three of the compound radials are Fi(. 205

present, they are generally distributed in the Diagram shown.- arrangement of plates
right posterior, the anterior, and the left antero- ^^^^^^^^\
lateral rays; but when only one radial is «, ^ a", Anal ami lower tnbe plates (after
bisected, it is constantly that to the right of

the anal area. The phases exhibited by the last-named plate in its palaeonto-
logical development furnish excellent differential characters. The superradial,
or arm-bearing portion of the plate, is situated in the earlier forms directly
in line with the inferradial or lower part of the plate ; but in later forms
it is pushed to the right by the gradual increase in width of the ventral sac.
The inferradial remains constant in position, but when supporting the sac, as
is usually the case among the later forms, it receives the name of radiancd.
Primitively, however, as was shown first by Wachsmuth and Springer, and
subsequently by Carpenter and Bather, the radianal represents the lower
portion of the right posterior radial ; and it has, therefore, nothing in common
with the anal plate, which is a specialised interradial.

Under the Fistulata are included the following families : — Hybocrinidae,
A nomalocrinidae, Heterocrinidae, Belemnocrinidae, Catillocrinidae, and Calceocrinidae,
comprising the monocyclic forms ; and Gasterocomidae, Cyathocrinidae, Poterio-
cr in ii fiic [Encrinidae], and Agassizocrinidae among the dicyclic.

Family 1. Hybocrinidae. Zittel.

Base mononjclic. B«sals foe, high. T1ie% right posterior radial compound ; the
inferradial supporting the ventral sac ; the superradial extremely small or undeveloped.
I 'en fnil ,sv//; in its most primitive foi'm, extending but little above the rest of the legmen.
( )rdo\ ician.

ffybocrinus, Billings. Calyx cup -shaped or obconical. Inferradial large,
angular above ; supporting to the right a very small superradial, and to the
left the first tube-plate, which generally resembles the superradial in form and
size. It with a crescent-shaped facet. Arms simple, devoid of pinnules, and
composed of quadrangular joints. Ordovician ; Canada, Kentucky, and
Tennessee.

II'ijilncAnm, Grewingk (Fig. 256). Like the preceding, but with the
inferradial sloping only to the right, and supporting a small, trigonal super-.

15-2 ECHIXODERMATA— PELMATOZOA SUB-KINGDOM in

radial. On the left it supports small plates of the ventral sac, without the
intervention of a larger plate. Ordovician ; St. Petersburg.

Hybocystes, Wetherby. Arrangement of calycine plates the
same as in Hybocrinus, but differing in the arm structure.
Three of the rays bearing primitive arms composed of but
few joints ; ambulacral furrows passing from the ventral to
the dorsal side of the arms, and continued upon the surface
of the E, The two other rays are without arms, and the
ambulacra follow the surface of the calyx, passing down so
far as to enter the basals- Ordovician ; Kentucky.

Petersburg. calyx Ba&i'ocninus. Volborth. Like Hoplocrinus, but the right

seen from the anal . *

side (after ore- posterior and the anterior ray without arms ; apparently
inferradials only are developed. Ordovician ; St. Petersburg.

Family 2. Anomalocrinidae. Waclismuth and Springer.

Base monocydic. Radials very irregular in form, the right posterior and left
antero-lateral ones compound, all of tliem laterally in contact. Ventral sac small,
tubular ; its lowermost plate resting in the angle formed by the superradiol to the right,
and the upper end of the simple radial to the left. Arms uniserial, bifurcating' at
intervals. Pinnules or small armlets given off from each arm-joint on one side only,
as far as from one bifurcation to the next, ivhen they change to the opposite side.
Ordovician.

Anomalocrinus, M. and W. B five. Unique in that the large simple R of
the posterior ray is often longitudinally bisected in the median line. A small
quadrangular supplementary piece enclosed within the basal ring. Tegmen
composed of large plates. Column strong. Ordovician ; North America.

Family 3. Heterocrinidae. Zittel (emend. W. and Sp.)

Base monocydic ; basals five ; one or more of the radials compound. The infer-
radial of the right posterior ray supporting to the right the superradial, and to the left
the ventral sac. Anals absent. Arms uniserial. Ordovician and Silurian.

Heterocrinus, Hall (Stenocrinus, W. and Sp.) Crown sub-cylindrical, calyx
small, arms long. Three of the R compound ; the others simple, and shorter.
The inferradial of the posterior ray has the form of an axillary, supporting to
the left the ventral sac, and to the right the superradial. Arms comparatively
stout, giving off long branchlets at intervals, which often branch again.
Column very large, pentagonal, and quinquepartite ; the lines of suture inter-
radial in position. Ordovician ; North America.

Ectenocrinus, S. A. Miller (Heterocrinus, W. and Sp. non Hall). Like the
preceding, but the arms formed of continuous series of syzygies comprising two
plates each, the epizygals giving off long armlets. Column of moderate size,
round, and tripartite ; axial canal large and pentalobate. Ordovician ; North
America.

Ohiocrinus, W. arid Sp. Differs from Heterocrinus in the details of its arm-
structure, and in the form of the ventral sac. Arms ten, long, and giving off
from every third or fourth joint long filiform armlets, which extend to the full
height of the main arms. Ventral tube resting upon the left sloping side of
the right posterior inferradial (RA\ and ascending spirally with the adjacent

ORDER in C1UXOIDEA— FISTULATA ir,:i

convolutions in contact. Column strong, obtusely pentagonal, and quinque-
partite. Ordo\ ician ; North America.

/"••/•/////*, Hall. l> five, small : // five, the right posterior one compound.
Tin- lower section of tin- latter, which serves as radianal, nearly of the same
sixr as the other //, hut angulai above instead of concave. It supports the
superradial on the right, and the ventral sac on the left; it is so large as to
extend considerably above the level of the other //, thus assuming the aspect
of an axillarv hrachial. Ventral sac composed at its posterior side of a longi-
tudinal row of lame, solid, elongate plates; at the other sides of short, delicate,
transverse pieces; the former plates being attached to the It A, are -easily mis-
taken for arm ossicles. Arms without pinnules, branching. Column sharply
pentagonal ; the angles radially disposed. Ordovician ; North America.

Herjicfu,rinn.t, Salter (Myoledactylus, trail). B five, of irregular form and
size. R five, the right posterior one horizontally divided. Ventral tube long
and narrow, and resting upon the sloping upper face of the inferradial. Arms
mm pinmilate, branching. Column evolute at its upper end, and more or less
round ; involute and crescent-shaped toward the terminal end, with large cirri
springing from the two horns of the crescent ; section sharply pentagonal.
Silurian : North America and Europe.

Family 4. Belemnocrinidae. Wachsmutli and Springer.

ic ; cylindrical to ovoid. It is composed of five large, elongate,
irregular pieces, ami is pierced by a small canal which widens slightly at the upper
''IK!. Eadials five, quadrangular, and separated posteriorly by a narrow IRA.
I >' nf r<d sac large, composed of hexagonal plates, the angles of which are perforated.
.In us hit>;/, (j icing off armlets alternately at intervals. Column round vr pentagonal ;
in the latter case having its angles radially directed. Cirri, wlten present, interradial
in position. Sub-Carboniferous.

Bdcmnocrinus, White. Burlington Group; Mississippi Valley.

Family 5. Catillocrinidae. Wachsmutli and Springer.

Base monocydic ; dorsal cup *« m-rr- shaped ; general symmetry of the calyx
greatly disturbed. Basals irregular in form, their number unknown ; radials still
more irregular both in form and in size. Most of the arms given off from two of
the radials, n-lii<-h are sometimes five or six times larger than the other three; they
are simple, quadrangular, ami rest within small sockets directly upon the radials.
Anal plates wanting. Ventral tube heavy, composed of very long, longitudinally
arrange*/ crescent-shaped pieces, and supported directly by the radials; it exhibits a
wide open groove along the anterior side, which prolaUy -iw* covered by small

- Devonian arid Sub-Carboniferous.

< '"fillocrinus, Troost. Crown, when the arms are closed, elongate, cylindrical.
Calyx basin-shaped, concave at the base, truncate at its upper margin. Basal
disk small. R five ; those of the two antero-lateral rays fully six times as wide
as the others, and expanding upwards, so as to encroach upon the smaller ones.
The larger R support twelve to sixteen arms ; the smaller ones rarely more
than one each. Sub-Carboniferous ; North America.

Mycocrinus, Schultze. Dorsal cup mushroom -shaped. Plates massive,
irregular, and without ornamentation. B two (according to Schultze), one of

154 ECHINODERMATA— PELMATOZOA SUB-KINGDOM in

them twice as large as the other, and the two forming a knob-like body. E
five, their inner edges resting upon the angular margin of the basal disk ; they
spread broadly outward from the B, extending far beyond them. The two
larger R separated at the posterior side by two equal smaller plates ; and at
the anterior side by a single plate having a quite narrow upper face. M.
boletus, Schultze, apparently with fifteen arms ; their structure unknown.
Middle Devonian ; Eifel.

Family 6. Calceocrinidae. Meek and Worthen.

" Inadunata Monocyclica, in which a bilateral symmetry along the left anterior
radius and right posterior inter-radius has been superinduced in conjunction with
bending of the crown on the stem in such a way that the right posterior interray lies
along the stem ; with the left anterior, right posterior, and right anterior radials com-
pound ; with anal x (IRA) shifted over the right posterior radius, usually into the
right posterior interradius, and supporting a massive tube ; with three, rarely four
arms, of which two are as a rule peculiarly modified and bear armlets or pinnules." -
Rather, The Crinoidea of Gotland. Ordovician to Sub-Carboniferous.

Castocrinus, Ringueberg. B distinct, all entering into the articular surface
of the stem. The right posterior, and right antero-lateral superradials
joined by ill-defined close suture, each abutting with one side on the
adjacent large simple R. The lower plate of the tube supported by the
right posterior superradial only, while the right antero-lateral superradial
supports the first brachial of the right antero-lateral arm. The right posterior
and right antero-lateral superradials separated from one another, and also
from the ventral tube, by the right posterior and right antero-lateral R. Arms
four. Ordovician ; North America. Type, C. furcillatus, W. R. Billings sp.

Euchirocrinus, M. and W. B unfused, or perhaps sometimes the left pos-
terior fused with the left antero-lateral one. The right posterior and right
antero-lateral superradials fused in a T-shaped piece, which abuts with either
wing on the corners of the large simple R. The right posterior and right
antero-lateral inferradials separated from one another and from the tube
by the T-piece ; tube supported by the whole upper margin of the latter.
Arms three. Ordovician and Silurian ; North America. Type, E. punctatus,
Ulrich sp.

Calceocrinus (Hall) Ringueberg. Left posterior B fused with the left
antero-lateral one ; the fused plates very rarely entering the stem articula-
tion. The posterior and right antero-lateral B bounded for some distance by
the large R. T-plate separated from the large simple R by the right
posterior and right antero-lateral R; it is low, wide, and occasionally very
small. Tube supported by the T-piece and the two inferradials to the right,
but not touching the two large simple radials. Arms three. Silurian and
Devonian ; Europe and America. Type, C. typus, Ringueberg.

Halysiocrinus (Ulrich) Bather. B as in the preceding, but the fused
posterior and right antero-lateral ones never entering into the stem articula-
tion. T-piece either obsolete or concealed between the right posterior and
right antero-lateral inferradials, and the two large R in the stem articulation.
Tube supported by the inferradials to the right, which are in contact ; and
abutting by its lower corners on the two large simple R. Arms three. Bur-
lington and Keokuk Groups ; Mississippi Valley. Type, H. ventricosus, Hall sp.

V>KI>I:K irr

r Kl NOI I )EA— FISTULATA

Gatteroooma antiqua, QolAt Devonian; Priim,
Eifel. o, Calyx seen from one side ; b, Anal aspect ;
< , .Teginen. »/l (after L. Schultze).

Family 7. Gasterocomidae. Warhsmnth and Springer.

Base dic>/<-lir. fnfnilxixals anchylosed into an undivided disk, which is
by a hi nir </u<i>/riluhate canal. Radials large; articular facets directed outward,
horseshoe-sluiped, occupy i/i't //m/7// the whole outer face of the plates, and pierced //// "
large dorsal canal. Anal opening low down, situated directly above the anal plate and
fa-,, ,-,1,1'nih. Tegmen composed of five interradials, five orals, and ambulacral
plates. Devonian.

Gasterocoma, Goldf. (Epactocrinus, Miiller), (Fig. 257). Irifrabasal disk
extending but slightly beyond the column ; surrounded by five B, of which
the posterior one is slightly truncated.
R five, three of them equal, the two
posterior ones irregular; the latter
enclose the IRA and anal opening,
which is surrounded by a few small
pieces. The arms, as indicated by the
character of the radial facets, either
recumbent or widely divergent. De-
vonian ; Eifel.

Nanocrinus, Miiller. Similar to the
preceding, but only four of the R
arm -bearing. The right antero - lateral one, however, has two articular
facets, and evidently supported a pair of arms instead of a single one ; the
anterior R is considerably smaller, and has no articular facet. Devonian.

Achradocrinus, Schultze ; Scoliocrinus, Jaekel. Devonian ; Germany.

Family 8. Cyathocrinidae. Roemer (emend. Wachsmuth and Springer.)

Base dicyclic. Radials simple or compound; their upper edges furnished with
a small crescent-shaped facet. Radials and arm-plates united by close suture, as are
the latter among each other. IRA usually, and RA occasionally present. Tegmen
with five orals and a madreporite, extended into a strong ventral tube. The disk
ambulacra resting on the lateral margins of two large interradial plates ; they are
lined by side-pieces, and roofed over with covering plates. Arms without pinnules,
long, branching, and uniserial. Ordovician to Carboniferous.

Dendrocrimis, Hall (? Palaeocrinus, Billings). Calyx obconical, higher than
wide, unsymmetrical. IB five, equal. B five, the largest plates in the
calyx; the posterior one truncated at its upper face, and supporting a large
anal plate. Four of the R pentagonal and simple ; the right posterior one
compound, with the two parts vertically arranged. IRA succeeded by two
or three plates which form the base of the ventral sac, but are partly
enclosed in the calyx. Ventral sac very large. Arms long and branching ;
column sharply pentagonal, or sub-pentangular. A number of species occur
in the Ordovician of North America, but only a single doubtful one known
from the Silurian (Niagara Group).

Homocrinus, Hall (Fig. 258). Like the preceding, except that the arm-
bearing portion of the right posterior radial is pushed over toward the right,
so as to support, conjointly with the anal, the ventral sac. Silurian ; North
America. Devonian ; Rhineland.

Gastrocrinus arid Rhadinocrinus, Jaekel ; Bactrocrinus, Stein. Devonian.

156

EC HINODERMATA— PELM ATOZOA

SUH- KINGDOM III

Ci/athoa-iiws, Miller, emend. AY. and Sp. (Figs. 259, 260). Dorsal cup
cup-shaped, bilaterally symmetrical. IB five, equal. B large ; the posterior
one truncated for the support of an anal plate. R five, all simple ; their upper

faces provided with a facet occupying less
than the full width of the plates. Ventral
sac rarely extending to more than one-half
the height of the arms. The number of
costals extremely variable among the rays.
Arms rather delicate, composed of elon-
gate cylindrical joints, and giving off" numer-
ous branches, most of which divide again.
Column round. Ordovician to Sub-Car-
boniferous ; Europe and North America.

Lecythocrinus,
Miiller, emend.
Zittel (Figs.
225, 261).1
Like the preced-
ing, except that
the infrabasals
are very small,
and entirely
concealed by
the column.
Ventral sac in
the form of a
long tube, and
e composed of
numerous, very
regularly ar-
ranged hexa-
:onal plates,
o 1 u m n o b-
tusely quad-
rangular, com-
posed of long
peripheral canals.

FIG. 258.

Homocrinits curtus, Miill. sp.
Devonian ; Schonecken, Eifel.
«, Calyx from the anal side, showing
ventral sac and one arm (right and
left sides reversed) ; b, Stem ;
of stem-joint (after Schultze).

FIG. 200.

a, Cyathocrinus longimanus, Aug. Silurian ;
Gottland. Crown of the natural size (after
Angrlin); b, C. ramosus, Ang. Portion of an
arin viewed from the side ; c, Ventral aspect of
same (enlarged) ; d, C. mulvaceus, Hall. Sub-
Carboniferous ; Burlington, Iowa. Tegnien
perfectly preserved ; e, The same after removal
of the covering pieces and orals (after Meek and
Worthen).

FIG. 259.

ntft. Diagram of dorsal
cup (after Bather).

joints, and perforated by a large central and four
Devonian ; Eifel.

Gissocrimis, Ang. (Fig. 262). IB three to five. B five; the posterior one
truncated, and supporting an anal plate. Radial facets elliptical in contour.
Ambulacra roofed over by alternately arranged covering pieces. Ventral
sac long, always laterally folded. Madreporite well defined. Arms long,
regularly bifurcating. Silurian ; Gottland and England. Devonian ; Eifel.

Arachnocrinus, M. and W. Calyx very small, resembling Cyathocrinus in
the arrangement of its plates, but forming a bulbous protuberance from which
the robust arms stretch out horizontally. Silurian and Devonian ; Europe and
North America.

1 [The type-specimen upon which this genus was founded (L. Eifelianus, Miill.) was regarded
by Schultze as an abnormal variety of Ta.rocnnus, and the specific name was changed by him to
T. briareus. But Taxocrinus has no such ventral tube, nor has it peripheral canals. In the latter
respect Lecytkocrinus differs also from Gissocrinns, with which it otherwise has close affinities.]

J

OHDKK III

CRINOIDEA— FISTULATA

157

.1A/.s//'/'"//'///s, Bather. Probably merely a variety of Cyatliocrinus, with
which it slum's in structure of the calyx and mode of branching. The arms,
however, are relatively longer, as is also the ventral tube ; column quinque-
partitc. Silurian; Dudley, England.

AV/7/0/-/-/////.S-, Aug. Calyx small, cup-shaped, unsymmetrical. IB five, high,
si ight ly protuberant. B five, three of them hexagonal and equal ; the posterior
pair indented l.y the radianal. R five, very large, with excavated facets. HA
small, rhomlioidal, and supporting the ventral sac. Arms ten, giving off
a mi lets from alternate sides of each or of every second or third joint
throughout their entire length; in some species the armlets give off sub-
branches. Ventral sac in the form of a tube which coils upon itself like a
snail at about one-fourth the height of the arms. Anal opening situated
anteriorly at the base of the tube. Silurian ; Gottland.

Wachsm. Differs from Cyathocrinus in having massive arms,

FIG. 262.

i n a x Kifilin a ».<,
Mull.' Itcvoiimii; Eiti-1. !{,•-
stored (afti-r Srhult/e).

s, Phill. Silurian; Gott-
land. Crown of the natural size (after Angelin) ;
b, G. p^mctuosus, Aug. Tegnien ; c, Ventral and
lateral aspect of the arms (enlarged).

composed of rather short, heavy, almost circular pieces, and exhibiting very
narrow ambulacral furrows. In some species the IE A sustains a diminutive
supplementary piece to the right, which is wanting in others. Ventral sac
composed of but few rows of heavy plates, longitudinally arranged. Column
stout, obtusely pentagonal, and quinquepartite ; axial canal very large. Sub-
Carboniferous ; North America.

Euspirocrinus, Ang. (Fig. 219). Dorsal cup conical, composed of massive
plates. IB five ; B five ; R with a deep and broad articular facet, notched for
the passage of the axial cord. IRA large, rising above the level of the R.
K' idianal somewhat smaller, and supporting a plate of the ventral tube
which takes part in the dorsal cup. Tube cylindrical, composed of relatively
large plates. Tegmen formed of five interradial pieces, which support by their
lateral edges two rows of side pieces enclosing an irregular row of covering
plates. Madreporite small ; column quinquepartite. Silurian ; Gottland.

158 ECHINODERMATA— PELMATOZOA SUB-KINGDOM in

Streptocrinus, W. and Sp. (Ophiocrinus, Ang. non Salter nee Semper).
Plates of the dorsal cup as in Cyathocrinus. Ventral sac composed of about
eight rows of hexagonal plates, some of which are deeply folded transversely,
so as to produce well-marked depressions on the surface. Arms slightly
bending downward; their ambulacral grooves narrow, and provided with
covering pieces only. Silurian ; Gottland.

Tenarocrinus, Bather. Dorsal cup broad, and composed of thin plates ; the
truncated posterior B supporting a large IRA. The right posterior E com-
pound; its superradial shifted to the right; but the inferradial, notwith-
standing its slanting position, gives no support to the ventral sac. The latter
is very large, longitudinally folded, and covered with transverse rows of
pits. Column round, with very wide axial canal. Silurian ; Dudley,
England.

Parisocrinu-s, W. and Sp. Dorsal cup obconical, composed of five IB, five
B, and five R, with an anal and radianal ; the latter two together supporting
the long, cylindrical, ventral sac. Upper edges of the R excavated so as to
form a narrow semicircular facet for the reception of the first costals ;
number of the latter very variable among the rays. Arms multibrachiate,
divergent, and filiform at their tips. Column round. Devonian ; Germany.
Sub-Carboniferous ; North America.

Atdestocrinus, W. and Sp. Dorsal cup elongate, always more or less con-
stricted along the suture line between the basals and infrabasals. IB five,
large, forming an almost solid ovo-cylindrical body. B five, long and narrow ;
R five ; four of them equal and arm-bearing, the anterior one less than half
the size of the others and not arm-bearing. Costals 4x4, the uppermost
axillary, and supporting two main arms ; armlets given off on alternate sides
from every second plate. Anal interradius as in the preceding. Burlington
and Keokuk Groups ; Mississippi Valley.

Sphaerocrinus, Roemer, and Achradocrinus, Schultze. Of these only the
structure of the calyx is known. The dorsal cup in both forms is globular,
composed of very thin plates, and the arms are pierced by a dorsal canal. In
the first-named genus IRA and HA are both represented, and it has an
eccentric anal opening which is directed upwards. But in the second RA is
wanting, and the position of the anus is strictly lateral, it being situated in
the suture line between the posterior radials. Middle Devonian ; Eifel.

Codiacrinus, Schultze. Calyx small, resembling a poppy head. IB five ;
B five ; R five ; the plates within each circlet equal to one another, and
laterally in contact. Devonian ; Germany.

Lecythiocrinus, White. Arrangement of calyx plates as in the preceding,
but with wider radial facets ; these are directed upwards instead of obliquely
outwards, and are provided with transverse ridges and well-defined ligamentous
fossae. Coal Measures ; North America.

Family 9. Poteriocrinidae. Roemer.

Base dicydic. Infrabasals five, sometimes hidden by the column. Basals five ;
radials jive, with transverse articular ridges. Anal and radianal generally repre-
sented ; and lower plates of the tube frequently entering into the dorsal cup. Ventral
sac large ; elongate or balloon-shaped in the earlier forms, small and conical in the
later ones ; it is composed of hexagonal plates, having the angles perforated by pores.

OKDKK III

CRINOIDEA— FISTULATA

1 .V.)

in,'/ nil

.•Inn* xi in I'lr "/' lifii n<-h hiy, /////>/W, inti r/W.v'/^/, "/' OGCOtivnotty
/Kiriii't /"/,'/' iiinniih's. Devonian and Carboniferous.

Pott'i-i'"-rinit.^ Miller. Dorsal cup obconical; plates thin and plicated arolind
their margins so as to form triangular pits at the angles. IB equal ; B high..
Three of the /.' hexagonal; the posterior and the right postero-lateral ones

^c7

FIG. 204.

Diagram showing arrangement
of ]>lates in the dorsal cup of
Scaphioc ri n u s.

Sniji/i me, -inn* it, i ('«•//.-.•, Hall. Sub-
Carboniferous (Keokuk (Jroup) ;
Crawfordsville, Indiana. Natural
si xi '.

FIG.

Diagram of '//•"/'/"'»''''" "•'-'• ''', '"-
frabasals ; ^, Basals ; r, Hadials ;
c, Anal ; br, Brachials (after
Bather).

FIG. 2f.:,.

Woodocrin UK MiKTmlnr.
tj/lus, de Kon. Perfect
specimen from the Car-
boniferous Limestone
of Yorkshire (after d«
Koninck).

heptagonal, and rising above the level of the others.
Articular facets crescent-shaped, and rarely occupy-
ing the full width of the plates. Anal and radianal
both present. Ventral sac very large, tubular, and
extending to the full length of the arms ; its two
lowermost plates partially incorporated into the sac.
Arms long, branching, composed of cuneate joints,
alternately arranged. Column round or obtusely
pentagonal. Upper Devonian and Sub-Carbon.

Lophocrinus, v. Meyer. Devonian ; Nassau.

Scaphiocrinus, Hall (Hydriocrinus, Trautsch.),
(Figs. 263, 264, 269). Dorsal cup low cup-shaped
to saucer-shaped. Arrangement of plates and mode of articulation as in the
preceding ; but the upper faces of the R form a horizontal line, and are
completely occupied by the lower faces of the first brachials. Costals one
or two ; the axillaries provided with transverse ridge and fossae similar to

160 ECHINODERMATA— PELMATOZOA SUB-KINGDOM in

those of the It. Arms long, uniserial, branching, and composed of wedge-
shaped joints, alternately arranged. Sub-Carboniferous and Coal Measures.

Scytalocrinus, W. and Sp. Dorsal cup generally deep. Arrangement of
calyx plates as in the preceding, from which it differs in the character of the
arms. These are stronger, and remain undivided after the first bifurcation,
which takes place above the first or second brachial. They are straight, and
composed of moderately short, very slightly wedge-shaped joints. Pinnules
long and rather closely abutting. Sub-Carboniferous.

Decadocrinus, W. and Sp. Dorsal cup very short, concave at the bottom.
Arrangement of plates of the dorsal cup as in the preceding, but the arms
simple and thinner, and composed of long, decidedly cuneate joints, which
give them a strongly waving or zigzag outline. Pinnules very robust,
closely resembling armlets, and widely separated. Sub-Carboniferous ; North
America.

Woodocrinus, de Kon. and le Hon (Phttocrinus, de Kon. ; Pachylocrinus, "VV. and
Sp.), (Fig. 265). Dorsal cup saucer-shaped. IB five, small, generally
covered completely by the column. B large, their lower portions curving
inward together with the IB, and forming a concavity. Anal area and mode
of articulation as in Scaphiocrinus. Ventral sac short, bulging toward the
upper end. Arms twenty or more, uniserial, heavy, and closely folded so
as to be laterally in contact; arm-ossicles very short. Pinnules long and
numerous. Column round. Sub-Carboniferous ; England and North America.

Zeacrinus, Hall (Troost). Resembling Woodocrinus in form and construc-
tion of the dorsal cup, but with short, thick, sub-pyramidal ventral sac.
IRA and RA both present ; the latter especially large, and deeply inserted
between the B. Arms short, uniserial ; the two main divisions of each ray
giving off numerous branches toward the inner side. These branches fit so
closely together that when the arms are closed the crown appears like a
perfectly solid body. Arm -ossicles short, transversely arranged. Middle
and Upper Sub-Carboniferous.

Coeliocrinus, White, and Hydreionocrinus, de Kon., are closely related to
Woodocrinus and Zeacrinus. They are distinguished chiefly by the form of the
ventral sac, which in Coeliocrinus is balloon-shaped, and in Hydreionocrinus mush-
room-shaped. They are found in the Lower and Upper Sub-Carboniferous
respectively.

Graphiocrinus, de Kon. and le Hon (Fig. 266), and Bursacrinus, M. and
W., differ from the majority of the Poteriocrinidae in having but one anal
plate, RA being absent. Dorsal cup depressed, concave at the bottom ; IB
very small, generally covered by the column. Graphiocrinus has ten main
arms, which are simple ; and the ten main arms of Bursacrinus give off
branches in a similar fashion as in Zeacrinus. Sub-Carboniferous ; North
America.

Miller and G-urley describe under Aesiocrinus a Carboniferous form agree-
ing with Graphiocrinus in the construction of the calyx ; but the plates of the
ventral sac are extremely heavy, and enclose a narrow cavity ; while the
plates of the sac in the typical form are rather delicate, and the inner space
is relatively wider

[In addition to the above, the following genera have also been associated with the
Poteriocrinidae : — Cromyocrinus, Phialocrinus, and Stemmatocrinus, Trantsch. ; Eupachy-
crinus and Erisocrinus, M. and W. ; Geriocrinus, White ; and Ulocrinus, Miller and

<>KPKK III

CRINOIDEA— FISTULATA 161

(Jurli-y. Although agivring with this family in a general way, they are readily dis-
tinguished from the typical forms by certain characters which they possess in common
with tin- K,i<-riniibn'. The dorsal cup is saucer-shaped, and composed of heavy plates ;
the articular faa-s of tin- radials are provided with well-marked muscular fossae ; tin-
arms vary fnmi Unix-rial to biserial within the limits of the same genus ; and the ventral
sat- is reduced to a small cone, extending but little above the level of the ventral di.-k.

These genera, according to Wachsmuth and Springer, constitute, together with the
genus Encrinus, a group which is sufficiently distinct to be recognised as an inde-
pendent family.

European writers, on the other hand, have almost without exception agreed in
a>MK-iating Encrinus in the same category with recent Crinoids ; the reasons for this
being -partly because it is a Mesozoic form, partly because it has axial canals along the
inner floor of the dorsal cup, and, finally, because anal plates are wanting. But the
imaginary line which was formerly conceived as separating the Palaeozoic from the
Neozoic Crinoids, has now been generally abandoned ; and as axial canals have been
found to exist among Palaeozoic forms as well as among the later ones, the only vital
distinction remaining is the presence or absence of anal plates.

In point of fact anals are present in most of the above-named genera. Cromy-
ocrinus and Eupachycrinus have both an RA and IRA ; Phialocrinus has only the
IRA, and Ulocrinus only the RA ; but Stemmatocrinus and Erisocrinus agree with
Encrinus in having neither IRA nor RA. Hence, if the division between the Poterio-
crinidae and Encrinidae be established simply upon the presence or absence of anal
plates in the cup, Stemmatocrinus and Erisocrinus are necessarily included under the
latter family, and the remainder excluded. But if other characters be chosen as
criteria, such as the mode of articulation, and the reduction of the ventral sac, then
all of the above genera must be included in the same family with Encrinus. The latter
course appears preferable-; especially since the gradual disappearance of anals may be
regarded as a natural consequence of the decrease in size of the ventral sac. Adopting
this course, the family Encrinidae may be denned as follows : —

Calyx more or less saucer -sJiaped, with dicyclic base. Infrabasals Jive, small, generally
concealed beneath the top stem-joint. Articular faces of the radials forming a horizontal line,
and completely occupied by the first costals ; faces provided with large muscular fossae, and a
perforated transverse ridge. Costals one or two. Ventral sac rudimentary ; anal plates gener-
ally absent. Tegmen (in Encrinus) elevated, composed of ratJier heavy plates. Arms usually
ten, rarely five or fourteen ; pinnule-bearing. Carboniferous and Trias.]

Cromyocrinus, Trautsch. (Fig. 267). Dorsal cup low, cup- or saucer-shaped.
IB moderately large, always projecting beyond the column. IRA large ;
RA barely touching the ventral sac ; no plates of the latter
entering the dorsal cup. Costals one to each ray. Arms
ten, rarely five ; uniserial or slightly interlocking from
opposite sides. Column round. Carboniferous Limestone ;
Moscow, Russia. Kaskaskia Group ; Mississippi Valley.

Eupachycrinus, M. and W. Dorsal cup as in the preced-
ing genus, but the IB much smaller, and concealed by the
column. B large. IRA and RA both represented ; the
latter very large, and supporting a small plate of the ventral FJG

tube, the lower part of which descends into the cup. Arms cromyocnnus'gioiuius
generally ten, rarely five or fourteen ; either uniserial, inter- M. and w Sub-car-

' , . * ' . ,J Tr . boniferous; Chesti-r, 111.

locking, or biserial. Kaskaskia Group ; Mississippi Valley. Natural size (after Meek

Ceriocrinus, White (Delocrinus, Miller and Gurley). a
Dorsal cup as in the preceding, but the posterior B more elongate than the
others, and supporting a small IRA ; upper end of the latter extending above

VOL. I M

162

ECHINODERMATA— PELMATOZOA

SUB-KINGDOM III

the M. Radianal wanting. Costals one or two ; the lower one frequently
extended into a spine. Arms ten, short and heavy, uniserial or biserial.
Kaskaskia Group and Coal Measures ; Mississippi Valley.

Phialocrinus, Trautsch. Construction of anal area as in Graphiocrinus, but
the mode of articulation between radials and brachials as in Encrinus.
Ventral sac small. Costals two; arms ten. Accompanies the preceding,
and found also in Carboniferous Limestone of Russia.

Ulocrinus, Miller and Gurley. Dorsal cup globular or cup-shaped. IB
projecting beyond the column. B large ; the posterior one variable in size,
but hexagonal like the others. IRA absent ; EA large, occupying the full
height of the R, and supporting the ventral sac. Arms unknown. Coal
Measures ; North America.

Erisocrinus, M. and W., and Stemmatocrinus, Trautsch., are without either
IRA or radianal. The former has five minute infrabasals, which are covered
by the stem ; those of Stemmatocrinus are large and perfectly anchylosed so as
to form a single plate. Certain Coal Measure species
of Erisocrinus are scarcely distinguishable from Encrinus
liliiformis. Sub - Carboniferous and Coal Measures ;
North America and Russia.

[Encrinus, Miller. The description of this genus is
retained in its original position under the ArticulataJ]

Family 10. Agassizocrinidae.
"Wachsmuth and Springer.
(Astylocrinidae, Roemer.)
Base dicyclic. Dorsal cup elongate,
with massive plates, and enclosing an
extremely narrow visceral cavity. Infra-
Nasals and la-sals very large ; the former
consisting of five elongate pieces, which
form an almost solid semiovoid or semi-
globose body. Radials very short, and
proportionally smaller than the other
plates of the cup. Anal and radianal
both present. Structure of tegmen and
ventral sac unknown. Arms ten. Sub-
Carboniferous.

Agassizocrinus, Troost (Astylocrinus,
Roemer), (Fig. 268). There is evi-
dence that this form was fixed in its
early stages by a stem, but subsequently became free-swimming. In the
adult condition the scar where the column was attached, as well as the
suture lines between the IB, became gradually obliterated by a secretion
of calcareous matter over the whole surface of the plates. Restricted to
the Kaskaskia Group of North America.

[Reference may be made here to Jaekel's recent Monograph, "Beitriige zur Kenntniss der
palaeozoischen Crinoideen Deutschlands " (Palaeont. Abhandl. von Dames und Kayser, ncue
Folge, Bd. III.), 1895. Unfortunately this excellent memoir was not available before the
present sheet was in print. — TRANS.]

FIG. 268.

Agassizocrinus laevis,
Koeiner sp. Kaskaskia
Group; Indiana, a, Crown,
nat. size; b, Ventral aspect
of the coalesced infrabasal
disk; c, Side-view of same,
nat. size (after M. and W.)

Scaphiocrinus multiplex,
Trautsch. Upper part of
Sub-Carboniferous ; Mos-
cow, Russia. Nat. size.

UKDKK IV

CIMXOIDEA— FLEXIBILIA 163

Order 4. FLEXIBILIA. Zittel.
i, p.p. \V. and Sp.,1 non Miillcr ; I>'hthyocrinacea, Neumayr.)

Base diet/die, with stem or stemless ; the proximal ring of the base in the latter
case enclosing a (?) dorsocentral (Carpenter). Arms branching, pinnulate or non-
jiiiiHuhift'. Ti'tiii/fK, .^ii fur as has been observed, composed of orals and numerous
exceedingly >•///////, loosely united, movable pieces; orals asymmetrically arranged.
Month mn/ ,niilnilifi-a exposed/ the latter roofed over by covering pieces and enclosed
bij side-plates. Ordovician to Carboniferous, and also Cretaceous.

Family 1. Ichthyocrinidae. Wachsmuth. and Springer.

./// jtlates of the calyx ami of the arms from the radials upward united by loose
nntni-c. or by muscular articulation. Base dicyclic ; infrabasals three, unequal, small,
f<i r<lt/ extending beyond the column, and fused with the top stem-joint; basals five,
small. Radials succeeded by one to six costals, which in species without interradials
increase in size upwards. Brachials united by more or less waving sutures, and their
lower edges furnished with tooth-like projections which ft into depressions on the
subjacent plates ; occasionally the projections are developed as separate patelloid plates.
Interbrachials, when present, rather irregularly arranged. Tegmen squamous ;
composed of five orals and numerous, very small, movable plates. Arms non-
pinnulate, and exhibiting a very wide and shallow ventral groove. Column round ;
the upper ossicles extremely short, and generally wider than the others. Ordovician
to Coal Measures.

Ichthyocrinus, Conrad (Fig. 270). IB very small; It and lower brachials
laterally in contact at all sides ; anals and interradials not represented.
Crown appearing like a perfectly solid body when the arms are closed.
Silurian to Coal Measures ; North America and Europe.

Lecanocrinus, Hall (Fig. 271), Like the preceding, except that only four
of the rays are laterally in contact, the two posterior ones being separated
by a rhomboidal RA and a somewhat larger IRA. Silurian ; North America
and Europe.

Taxocrinus, Phill. (Figs. 272, 273). All five R separated by inter-
brachials. Costals two, sometimes three. The posterior B larger than the
others, truncated, and supporting an IRA. This is followed by a longi-
tudinal row of small elongate supplementary anals, which are interposed
between numerous very minute irregular pieces. Plates of the four regular
interrays less numerous, larger, and more symmetrically arranged. Ordovician
to summit of Sub-Carboniferous ; North America and Europe.

Gnorimocrinus, W. and Sp. Like Taxocrinus, but with RA in addition to
IRA ; the former also supporting a longitudinal row of supplementary
anals. Silurian; Gottland.

OnycJwcrinus, Lyon and Gassed. Calyx depressed; arms spreading and
talon-like. IB rarely projecting beyond the R, and closely or only partially

1 [The three families embraced iinder this order, the Ichthyocrinidae, Marsupitidae, and
Uintacrinidae, are included by Wachsmuth and Springer under the Articulata (Articidosa) as
redefined by them. The non-pinnulate Ichthyocrinidae, however, are placed in a separate sub-
order under the name of Articulata Impinnata ; while the Marsupitidae, Uintacrinidae, and most
of the Mesozoic and Recent Crinoids constitute the second sub-order Articulata Pinnata. — TRANS.]

164

ECHINODERMATA— PELMATOZOA

SUB-KINGDOM III

fused with the top stem-joint. The posterior B larger than the rest, and
truncated or excavated at its upper face. Costals three to six, decreasing in
size upwards ; the two lower ones laterally united by a few large inter-
brachials. The posterior interray markedly different from the others ;
composed of a large number of exceedingly minute pieces, which enclose a
longitudinal row of six to twelve moderately small, quadrangular, anal plates,
supporting a small tube at the upper end. Tegmen formed by small, almost
microscopic limestone particles, and extremely flexible. Arms ten, giving
off clusters of armlets either from the sides at intervals, or only at their
upper ends. Middle Sub-Carboniferous ; North America and England.

Forbesiocrinus (de Kon. and le Hon), Hall. Differs from Taxocrinus in the
construction of the anal area. IRA and EA both represented. Inter-

FKJ. 270.

Ichthyocrinus lacris,
Conrad. Perfect
crown. Silurian
(Niagara Group);
Lockport, New York
(after Hall).

FIG. 272.

Taxocrinus intermedium,
W. and Sp. (after Wachs-
inutli and Springer).

FIG. 271.

Lecanocrinus Sill-
ingsi, Aug. Silurian;
Gottland. a, Calyx,
seen from one side
(right and left re-
versed); I, Crown,
seen from the anal
side (after Angelin).

Taxocrinus Meeki, Hall sp.
Perfect crown. Sub-Carbonifer-
ous ; Crawfordsville, Ind.

brachials very numerous, arranged in some cases in twelve or more rows.
Arms long, bifurcating, rather closely apposed, and with infolding tips.
Sub-Carboniferous ; North America and Europe.

^Mespilocrinus, de Kon. and le Hon. Crown small and unsymmetrical,
owing to the dextrorse arrangement of the arms. Posterior B truncated,
and supporting a small IRA, which is the only supplementary plate of the
dorsal cup. Costals and distichals two, followed by a very few free arm-
plates. Arms very short, closely folded, and inclining to the right, owing to
the cuneate form of lower brachials. Sub-Carboniferous; North America
and Europe.

Homalocrinus, Anisocrinus, Calpiocrinus, Cyrtidocrinus, Pycnosaccus, Aug. ;
Lithocrinus, W. and Sp. Silurian, Gottland.

OKDKH V

(•III NOM >KA— ARTICULATA

165

K.iinily -2. Marsupitidae. d'< )rl.i-nv.

Base dicydic. Dorsal cup large, composed of large, thin plates. Column absent ,-
/•,/,/vs,-///rr/ lii <i fhi/i jHitfaijonal, (?) dorsocentral, or ce.ntrodorsal plate.1 Infrabasals
five; basals five; nnliiilx five; interradials and anals wanting. Upper edges of
radiak furnished u-ith a small crescent-shaped articular facet, having a perforated
transverse ridge. Arms Irranching, unisrrial, muJ fi'«i'> rW //// dorsal canals. Struc-
t '•'>/ 1 ncn and pinnules unknown.

The only known ^I'lius is Marsupites, Mantell, occurring in the Upper
Cretin-rims (White Chalk) of England and Northern Germany (Fig. 274).

FIG. 274.

.Vi'/>-/'/./V.-s t>; ttn, i;,im -Is, Schlot. sp. Upper
-us ; Liiin-hurj,', Prussia. </, Calyx,
natural size ; h, J{;i«li;il, and a few of the ann-
li!iit«-s ; .-, Tips of the arms.

Uintacrinus Wcstphalicus, Scliliit. Upper Cretaceous ;
Recklingshausen, Westphalia, a, Calyx viewed from the
side ; l>, Inferior aspect. Natural size (after Schliiter).

Family 3. Uintacrinidae. Zittel.

^'/iiimetry perfectly pentamerous, plates thin, column wanting. Base monocydic ;
A//.NV//.S five, enclosing a small, pentagonal, (?) dorsocentral, or centr odor sal plate.
< v,.s/r//.s two, the upper one axillary, and suppoi'ting two rows of distichals which are
succeeded by palmar s. Interbrachials numerous, the lowermost ring interposed
between the costals. Arms long and pinnulate ; composed of very short, almost
circular ossicles. Pinnules heavy and closely abutting ; the lower ones united by
MI in res, and incorporated into the calyx.

The solitary genus Uintacrinus, Grinnell (Fig. 275), occurs in the Upper
Cretaceous of Kansas and Westphalia.

Order 5. ARTICULATA. Johannes Miiller.
(Neocrinoidea, Carpenter; Pentacrinacea, Neumayr.)

Tegmen coriaceous] studded with minute calcareous particles, or covered with well-
defined small plates of irregular arrangement. Mouth and food-grooves exposed ; orals

1 [This plate is supposed l>y Carpenter to represent the distal plate of the stem, and not the
proximal one. — TKANS. ]

166

ECHINODERMATA— PELMATOZOA

SUB-KINGDOM III

present in nepionic, frequently also in the adult stages. Plates of the dorsal cup
heavy ; basals and radials united by dose suture; radials and lower brachials by
muscular articulation or by syzygy. Radials laterally in contact, except in Thaumato-
crinus ; but small irregular plates are frequently interposed between the costals and
distichals. Anal plates represented only in the larval stages. Arms uniserial and
pinnulate, the ossicles pierced by a dorsal canal. Trias to Eecent.

The Articulata include all Kecent, Tertiary, and Mesozoic Crinoids, with the
exception of Marsupites, Uintacrinus [and Encrinus, according to Wachsmuth
and Springer]. They are chiefly characterised by the exposed condition of
the mouth and food-grooves, as well as by a canal which perforates the arms.

This is known as the dorsal or axial canal, and
contains a nerve-band and fibres of connective
tissue. Starting from the dorsally situated
chambered organ (Fig. 276), there are five canals
which traverse the basals as far as the centre,
where they divide into two branches which con-
tinue upward through the radials and brachials ;
and there is also in the radials a ring -canal
which serves to connect the longitudinal canals
with one another. In young individuals these
canals are in the form of open grooves on the
inner side of the plates, but they become per-
fectly closed in the adult condition.

Diagram showing course of axial canals [T° tne 4rtwulata (Articulosa) Wachsmuth

in the calyx .and arms of Encrinus. Canals an(j Springer refer only the Pseudomonocuclica ;

represented by dotted lines when pene- . r & J

trating the interior of the plates, and by that IS to Say, L/rmOlds which are Constructed

heavy lines when exposed on the inner ,v j- i- i i , • r • r ,r • r

side of the calyx (after Beyrich). on the dicychc plan, but in which the mfra-

basals are rudimentary, and are more or less

completely fused with the top stem- joint, and in which the last-named joint
is not the youngest in the stem, as is the case in all other forms. The
families thus embraced are the Apiocrinidae, Bourgueticrinidae, Eugeniacrinidae,
and Comatulidae among Mesozoic and later Crinoids, and the Ichthyocrinidae
among the Palaeozoic. The Ichthyocrinidae, which are devoid of pinnules,
are placed in the sub-group Articulata Impinnata ; the others, which are all
pinnulate, constitute the sub-order Articulata Pinnata. The Pentacrinidae and
Encrinidae, both of which are in all probability derived from the Poteriocrinidae,
are assigned by these authors to the Fistulata, and the same is also true of
the Plicatocrinidae and Holopidae, in which the top stem-joint is the youngest
joint of the column wherever the latter is represented.]

FIG. 276.

Family 1. Encrinidae. Roemer.

Dorsal cup low, saucer-shaped, with dicyclic base. Infrabasals five, very small,
and covered by the upper stem-joint. Basals five, large ; radials five, the articular
faces truncate, and provided with transverse ridges. Interbrachials absent, legmen in
the form of a vault. Arms 5 x 2 or 5 x 4 ; heavy and simple, closely abutting, and
either biserial or composed of alternately arranged cuneate joints. Column round,
rarely giving off cirri ; the terminal end thickened and laterally extended. Trias.

Encrinus, Miiller (Figs. 276-278). R succeeded by two costals, of which

ORDER V

CRINOI DEA— ARTICULATA

167

the upper one is axillary, and supports the distichals. Union Wi \veen the R
and first costals and between the axillary costals and first distichals is by
muscular articulation ; the two costals and the two proximal distichals form

/,/• i •-•

FIG. 277.

/•;/" -ri nits liliiformiti,
Mill.T. Muschelkalk ;
Hrannschwri-.

FIG. 278.

Portions of the calyx and arms of Encrinus. a, Interior
of calyx ; a*, Exterior of same ; b, Basal, upper surface ;
r, Radial, inner surface ; /3, One of the uniserial, and /3*, bi-
serial arm -plates; both of them traversed by duplicate
dorsal canals ; p, Pinnule ossicle (enlarged) ; br, First
brachial, under surface; frr*-, First and second brachials
joined together; inside, seen from below ; br*, First brachial,
upper surface, showing line of syzygial suture ; br2, Second
brachial (axillary), showing articular facets.

a syzygy, with their apposed faces dotted. Arms ten, or exceptionally
twenty; uniserial at their lower ends, but rapidly becoming biserial. Upper
and lower faces of stem -joints marked over their whole surface or only
around their outer margins with
radiating striae. Central canal
small, round. Abundant in the
Trias, especially in the German
Muschelkalk. The stem - frag-
ments of E. liliiformis not infre-
quently form massive beds of
limestone (Trochitenkalk).

Dadocrinus, v. Meyer. Like
the preceding, but smaller, and
with uniserial arms. Trias.

Holocrinus, Jaekel. Trias.

Family 2. Apiocrinidae.

d'Orbigny.

, , , . , , Afiooriuus Parkinsoni, Schlotheim. Great Oolite ; Ran villc,

Lall/X UnsymmetllCal, Composed Calvados, a, Calyx and upper stem-joints, viewed from the

nf Itonvii nJnf#Q "Rn<io <n<tt>tirlr\'mn'nf\ side; b, Ventral aspect; c, Articular surface of one of the

of tieaiy plates. ±fase pseuaomono- Stern.j0i'nt8 (natural size)!

cyclic ; the infrabasals completely

fused with the centrodorsal, but rarely visible within the basal ring. Basals jive,

radials five, occasionally separated by a few interbrachials. Tegmen composed of

Flo. 279.

168

ECHINODERMATA— PELMATOZOA

SUB-KINGDOM III

rather heavy plates ; mouth and anus not observed. Arms uniserial, branching, and
bearing long pinnules. Column round to sharply pentagonal, without lateral cirri ;
the proximal joint the largest of the stem; distal end thickened and forming a stout
root. Jura, Cretaceous, and Recent.

Apiocrinus, Mill (Figs. 279-281). Dorsal cup pyriform, supported by a
long cylindrical column, the proximal joints of which gradually expand in

FIG. 280.

Apiocrinus Parkinsoni, Schloth. Great Oolite; Ranville, Calvados. A, Diagram of calyx, showing course
of canals. These are represented by dotted lines when concealed within the plates, and by heavy lines where
visible on the inner surface of the basals. B, Median longitudinal section through the uppermost stem-joints,
showing empty space included between them ; b, Basal, seen from above and from the inside ; b*, Lower surface
of same ; ri, Radial, seen from without ; ri*, Inner aspect of same ; r2, and r%*, Corresponding views of first
brachial ; br, Arm-plates. (Canals are invisible in plates above the basals, except where they have become
exposed by weathering or abrasion.)

FIG. 281.

Apiocrinus Roissyanus, d'Orb. Upper Jura (Coral-Rag) ; Tonnerre, Yonne. Restoration (after d'Orbigny).

diameter, so as to become of equal width with the B. Upper face of the
centrodorsal bearing five, low, angular ridges, which correspond in their dis-
position with the suture lines of the IB. Radials followed by two costals,
which are laterally and longitudinally united by rather close suture. Upper
faces of the costals excavated and striated ; the free brachials perforated, and
furnished with well-defined transverse ridges. In a few species small inter-
brachials are interposed between the costals. Column round, the proximal
joints in contact only near the periphery ; inner portions of the joints wedge-
shaped, and leaving a hollow space between them. Lias to Cretaceous.

om>i:i< v

CRINOIDEA— ARTICULATA

169

stems occur notably in the Alps in great profusion, but calices
arc rare.

ii'ii'ffiinhif.rinus, d'Orb. Differs from the preceding in having costals im-
movably united with interbrachials. Solitary species : G. dilatus, d'Orh.
.Jura.

M/Ilericrinus, d'Orb. Closely allied to Apiocrinus, but articular facets of
ladials and brachials more strongly developed. Base occasionally with five
minute IB, which are coalesced with the top stem-joint (centrodorsal) ; the
latter extended laterally, and resting against the outer faces of the B.
Column more or less sharply pentagonal, with the angles interradially
directed. Lias to Lower Cretaceous.

.Icrochordocrinus, Trautsch. Jura and Lower Cretaceous.

< 'ulamocrinus, Ag. Recent; Galapagos Islands. (Cf. Literature, p. 124.)

Family 3. Bourgueticrinidae. de Loriol.

Dorsal cup small, pyriform, with shallow body-cavity, and composed of a centro-
!, five basals, five radials, and one to two costals. Tegmen (in recent foi'ms) cori-
acetnu, and with mouth surrounded by five orals. Arms five, thin, uniserial, and
bearing very long pinnules. Stem giving off numerous cirri ; composed of heavy dice-
box-shaped joints, both faces of which are provided with elevated transverse ridges, and
deep ligamentous fossae. Jura to Recent.

Bourgueticrinus, d'Orb. (Fig. 282). Centrodorsal unusually large, as wide
as the calyx at its greatest width, and wider than across the basals. R

FKJ. 282.

Bowmutterinus dlipti-
Mill. White Chalk:
Wiltshire. «, Calyx with
centrcxlorsal and two of
the stem-joints (nat. size);
l>, Ventral aspect (en-
larged); c, Stem-joints;
<l, Articular surface of
stem-joint; e, Cirrus.

FIG. 283.

Rhizocnnus pyriformis, Goldf. sp. Eocene ; Verona.
a, b, Calyx from one side (nat. size and enlarged);
c, !S;une from above, with three of the Jir in place ;
(I, Median longitudinal section of calyx (nat. size) ;
f, Calyx with slightly abraded outer surface, showing
suture lines between Ji and R ; f, Calyx with five rays,
seen from above (enlarged); g, k, Stem-joints (nat. size).

truncated at the upper face, and supporting very short costals. Structure of
arms unknown. Column round ; its joints almost as long as wide, the upper
ones wider than the rest. Upper Jura to Tertiary.

Rhizocrinus, Sars. (Conocrinus, d'Orbigny non Troost), (Fig. 283). Base
very large and elongate ; composed of five heavy plates which are more or
less fused. R typically five, but sometimes four, six, or seven ; short and
quadrate in form. Column slender, giving off branching cirri toward the
distal end ; composed of joints nearly three times longer than wide, and con-
stricted in the middle. Eocene, and Recent at great depths.

170

ECHINODEEMATA— PELMATOZOA

SUB-KINGDOM III

Family 4. Eugeniacrinidae. Zittel.
(Coadunata, Miller; Holopocrinidae, pp. Jaekel.)

Dorsal cup composed of Jive (rarely four) thick, rigidly united radials resting
upon a centrodorsal ; basals invisible, tegmen unknown. Costals compressed, flange-
like ; united by syzygial sutures, or fused
with one another. Arms uniserial, robust,
and incurving. Stem short, destitute of
cirri, and composed of but a few long
cylindrical joints with granulated or
striated articular faces. Dorsocentral
thickened and expanded. Lias to Lower
Cretaceous ; Europe.

Eugeniacrinus, Miller (Fig. 284):
Dorsal cup small, saucer-shaped, and
with shallow body-
cavity. Centro-
FIO. 284. dorsal covered with

Eugeniacrinus caryophyllatus, Mill. Upper Jura ; five radiating ridges.
Streitberg, Franconia. o, Calyx with centrodorsal, ^ invisible when the

seen from one side (nat. size) ; b, c, Ventral and dorsal

aspects, 3/2 ; d, d*, First brachial, inner and upper

surface ; e, Second brachial, seen from the inside (nat.

size) ; /, h, E. nutans, Goldf. Same locality ; /,/*, First tached, but f rom the

and second Br fused together, seen from the outside . , , . ,

and inside, respectively ; g, Arm-plate, figured in four COUrSC OI the axial

positions ; h, Dorsal and lateral aspects of an inrolled

at

^aT1nla /Fio- 285^ it

is apparent that

they are pushed upward so as to be completely enveloped
by the E. The latter are very heavy, closely united, and
sometimes completely anchylosed. The lateral margins of
their upper faces are extended upwards so as to form con-
spicuous projections ; the intermediate spaces are occupied
by transverse ridges and deep fossae. Costals two, the
upper one axillary. Structure of arms unknown. Abun-
dant in the Upper Jura, notably in the Spongitenkalk of
Southern Germany, Switzerland, France, and the Car-
pathians. Less common in the Dogger and Lower
Cretaceous of the Alps.

Jaekel1 divides Eugeniacrinus into the following sub-
genera : — Cyrtocrinus, Sclerocrinus, Tetanocrinus, Eugeniacrinus,
s. str., and Gymnocrinus. The chief differential characters
consist in modifications of the distichals, the arms, and
articular surfaces of the radials.

Eudesicrinus, de Loriol. Stem reduced to two short
thick segments which bear the five R directly. Lias.

FIG. 285.

Eugeniacrinus caryo-
phyllatus, Mill. Upper
Jura, o, Restoration,
without the arms (after

Tetracrinus, Miinst. R typically four, rarely three or operfto Bhy

how the silici-

five ; apparently reposing dire'ctly upon the column, as no Skeajal canals
B or IB are visible. Upper face of the centrodorsal
marked by four (sometimes three or five) prominent ridges which are radially
disposed ; lower face bearing about fifteen radiating prominences, which are

1 Zeitschrift der deutsch. geol. Gesellscli. Bd. XLIIL, 1891.

OKDKK V

CRINOIDKA— AKT1CULATA

171

not continued over the median portion of the plate. J! with transverse
ridges and large muscular fossae. Stem-joints barrel-shaped. Jaekel regards
the centrodorsal as representing the anchylosed B, notwithstanding the
absi'iicv of axial canals. Upper Jura.

PhyllocrinuSj d'Orb. Dorsal cup globose ; upper edges of 11 with narrow
articular facets, to either side of which are long, upright projections. 1'pjn-r
Jura and Lower Cretaceous, notably in the Mediterranean district.

Family 5. Holopidae. Zittel.

Base monooyclic ; stemless. Dorsal cup
aped, and formed of five fused
s, by which the body was either directly
attached, or, as was more probably the case,
it was suppwied by a cycle of basals
enclosei/ u: it bin the radials. Tegmen com-
posed of five large triangular orals, sur-
rounded by a narrow band of perisome.
Arms 5x2, uniserial, strongly incurving,
and composed of large thick plates.

Of the forms belonging to this
family, Cotylederma, Quenst. (Fig. 286), is

FIG. 286.

a, b, Cotyledermu docens, Deslongcli. Upper Lias ;
May, Calvados, n, Calyx seen from above ; b, Same,
from below ; c, d, C. lineata, Quenst. Lias 8 ; Assel-
fingen ; Baden, c, Centrodorsal ; d, Circlet of fused
(All figures of the natural size).

found in the Lias; Cyathidium,Steen&tr.
(Micropocrinus, Menegh.), in the
Cretaceous and Tertiary ; and
Holopus, d'Orb., at great depths
in existing seas.

FIG. 287.

hexagonus, Munst. Upper
Jura ; Streitberg, Franconia. a, Calyx with
radials and undivided base ; 7), c, Dorsal and
lateral aspects of same (slightly enlarged);
<'-/, First brachial, seen from the inside,
outside, and from below respectively.

Family 6.

Plicatocrinidae.

Zittel.

Base monocyclic, funnel-
shaped, quadrangular to hexa-
gonal, and formed of one solid
piece. Radials four, six, or eight
(rarely five or seven), short and
delicate. These support axillaries,
which give origin to two simple
arms composed of wedge-shaped
ossicles and united by muscular
articulation. Pinnules usually
composed of a single piece. Body-
cavity wide and deep.

Plicatocrinus, Miinst. (Fig.
287). Radials comparatively

Hyocrinti* MhelUmmx, VVyv. Thomson. Recent; Atlantic +>,:„ +V,0iV or+iViilnr fnppf"«

Ocean. . I, Individual twice the natural size. B, Tegmen several tnm> their artlCUlar laCCt

times enlarged ; am, Ambulacral furrows of the arms ; c, Dorsal crescent - shaped : the Outer
canals ; on, Anus ; m, Mouth ; o, Orals (after Wyville Thomson). . -,. n

faces longitudinally convex.

Pinnules undivided, except the proximal ones, which consist of three pieces ;
they are angular or keel-shaped along the dorsal side, and deeply furrowed

FIG. 288.

172

ECHINODERMATA— PELMATOZOA

SUB- KINGDOM III

on the ventral. Tegmen unknown. Upper Jura ; a rare form, found in the
Franconian and Swabian Alp.

Hyocrinus, Wyv. Thomson (Fig. 288). This recent form is obviously
allied to the preceding, but differs from it rather conspicuously in the mode
of branching of its arms. It has a heavily plated tegmen, with mouth sur-
rounded by large orals. Carpenter regards it as the type of an independent
family.

Family 7. Saccocomidae. d'Orbigny.

Calyx small, hemispherical, non-pedunculate. Eadials five, very thin, elevated
ridges along the median line, and enclosing an extremely small basal

Saccocomu pectinfita, Goldf. Upper Jura (Lithographic Slates) ; Eichstadt, Bavaria, a, Individual in natural
size ; 1>, Side view of calyx ; c, Calyx seen from below, 2/x ; d, Two of the lower arm-plates ; c, Two arm-plates of
a higher order with one of the branches ; /, The upper part of one of the arms straightened out ; g, Lower
brachials of .S'. tenella, Goldf. (Figs, d and g greatly, the others slightly enlarged.)

plate. Arms 5x2; thin, widely separated, and giving off alternately towards the
extremities - simple incurving branches. Arm-plates cylindrical; each side of the
ambulacral furrow lined ivith wing-like or spiniform projections. The entire skeleton
exhibiting a reticulated structure with coarse meshes. Upper Jura.

The only known genus, Saccocoma, Ag. (Fig. 289), occurs profusely in the
Lithographic Slates of Eichstadt and Solenhofen, Bavaria. It is a free-
swimming form, whose affinities with the monocyclic Plicatocrinidae were first
clearly demonstrated by Jaekel.1

1 Zeitschrift der deutschen geol. Gesellsch. Bd. XLIV., 1892.

OUDHK V

CRINOIDEA— ARTICULATA

173

//>•

Family 8. Pentacrinidae. d'Orbigny.

( '«l>ix small, bowl-shaped, ami with dicydic base ; but the infrabasals are either
ni'liniiiifiini, <>f 'o,//,///, •/,-/// ft-sin'lif.d in tlie adult state. The top stem-joint always the
youngest joint of the column. Basals five, radials five, costals one to two. Tegmen
flexible, studded with small, irregular, calcareous particles or delicate plates. Arms

niiuu rinidii lfnn<-hin'j,
pinnulate. Column long,
r or sub-pentagonal ;
angles interrudiatty
tJie cirri given off
radially. Upper and lower
faces of the stem -joints orna-
'! with a quinquelobate
figwrt. Trias to Recent.

Pentacrinus, Miller (Iso-
crinns, v. Meyer; Cladocrinus,
Ag. ; Cainocrinus, Forbes),
(Fig. 290). IB obsolete;
costals rarely more than two,
none of them pinnulate.
Arms very!! numerously
divided. Column more or
less pentangular ; the angles
of the axial canal, contrary
to the general rule in dicyclic
forms, are radially directed,
so as to correspond with the
outer angles of the stem.
Cirri very numerous ; stem
not thickened at its distal
end. Trias to Recent ; maxi-
mum in Lias.

Exquisitely preserved
specimens are found in the
Lower Lias of England, and
the Upper Lias in the vicinity
of Boll and Metzingen,
Wiirtemberg. A slab con-
taining no less than twenty-
four perfect crowns of P.
subangularis, Miller, with
long intertwining stems, is
preserved in the Tubingen Museum. There also may be seen a column
which Quenstedt traced for over 70 feet, without reaching either end.

M"facrinus, Carp. Differs from Pentacrinus in that the Pi are succeeded
by four to seven costals, of which the first and second form a syzygy. Where
seven costals are present, the fourth and fifth are also united by syzygy.
Angles of axial canal interradially disposed, so as to alternate with the outer

Pentacrinus (Extracrinus) briareus, Mill. Lower Lias ; Lyme
Regis, England (after Goldfuss). a, Stem-joints of P. subangutarit,
Mill. Upper Lias ; b, Column of /'. basaltiformis, Mill. Middle Lias.

174

ECHINODERMATA— PELMATOZOA

.SUB-KINGDOM III

angles of the stem. Arms moderately branching. Cirri generally directed
upwards ; those of Pentacrinus, as a rule, downwards. Recent ; Pacific Ocean.

Extracrinus, Austin. Base composed of five rudimentary IB and five B ;
radials with downward prolongations from their lower ends. The five inter-
radial petals on the upper and lower faces of the stem-joints narrower and
more lanceolate than in Pentacrinus. Lias to Recent.

(?) Balanocrinus, Ag. Stem-joints round, with serrated margins ; articular
faces marked by five crenulated ridges radiating from the centre. Lias to
Cretaceous.

Family 9. Comatiftidae. d'Orbigny.1

Pedunculate and fixed in nepionic stages, later losing the stem and leading a free
existence. Base pseudomonocyclic; infrabasals visible only in the ciliated larva,

afterwards becoming fused with
the top stem -joint. Basals,
which are large in the larval
condition, are transformed at
the end of the Pentacrinoid
stage into the so-called rosette.
Centrodorsal giving off numer-
ous cirri after detachment of
the stem ; its angles inter-
radially disposed, like the stem
of dicyclic Crinoids. Tegmen
coriaceous, naked or indurated
by thin calcareous plates.

••^'Z&Z'>> ' |ff

••>

Body - cavity very shallow ;
arms simple, interlocking,
Lias to Recent.

Wfh'l

W

Over 200 species are
represented in the present
seas, most of them being
inhabitants of shallow
water.

Antedon, Freminv.
(Alecto, Leach ; Comatula,
Lam. ; Pterocoma, Ag. ;
Decacnemos, Brorm ; Comatu-
Una, d'Orb. ; Hertha, Hage-
now ; Solanocrinus, Gleno-

a, Antedon (Solanocrinus) costatus, Goldf. Upper Jura (Diceras- tremiteS, Goldf.), (FigS. 235,

Kalk) ; Kelheim, Bavaria. Dorsal aspect of crown ; centrodorsal and Orki\ TVT ^.T.

pinnules not preserved (slightly reduced) ; b-d, A. scrobiculutus, Goldf. A a I). IVlOUtn central, anUS

Upper Jura; Streitberg, Franconia ; b, Ventral; c, dorsal; and PPppntriV- ppntrnrlnrcal
d, lateral aspect of calyx ; e, Arin-plate. ni r 1 C , C 0 r S a 1

button-shaped. Costals
two ; the upper one axillary. Arms ten or more. Lias to Recent.

Eudiocrinus, Carp. (Ophiocrinus, Semper). Like Antedon, except that it
has only five arms. Represented by one Neocomian and five Recent species.

1 Muller, J., Ueber die Gattung Comatula, etc. (Abhandl. Berlin. Akad.), 1847.
Ludwig, H., Beitrage zur Anatomie der Crinoideen (Zeitschr. fur wiss. Zool. XXVIII.), 1877.
Carpenter, P. ff., Report on the Crinoidea (Sci. Results, Chall. Exped., XI. and XXVI.), 1884-88.
Jaekel, 0., Entwurf einer Morphogenie und Phylogenie der Crinoideen (Sitzber. naturf. Ges.), 1894.

ORDER v CRINOIDEA— ARTICULATA I 7 :>

Adinometra, Muller (Comaster, Goldf. ; Phanogenia, Loven). Mouth
eccentric or marginal ; anus central or subcentral. Centrodorsal depressed,
discoidal ; covered with a single (rarely a double) row of cirri, or sometimes
altogether naked. Jura to Recent.

Pr&machocrinus, Carp. Centrodorsal hemispherical or conical, and covered •
with numerous closely set cirri. 11 succeeded by a single costal ; with high
distal faces and large muscle plates. Mouth central ; ambulacra symmetri-
cally disposed. Recent.

Atelecrinus, Carp. Centrodorsal acorn-shaped, and bearing five double
rows of cirri, those of each row altcri&ting with one another and with those
of adjacent rows. R separated from the Centrodorsal by a complete circle
of B. The first six or more orders of brachials devoid of pinnules. Recent.

Thaumatocrinus, Carp. Calyx plates as in the preceding, but with the
addition of five large interradials resting upon the basals, followed by small
irregular pieces between the costals at four of the sides ; the posterior
interradial bearing a short, solid, jointed appendage. Ventral surface
covered by a narrow band of perisome, and almost entirely occupied by five
large, symmetrically situated orals. Mouth central ; anus eccentric, and
extended in a short tube. Arms five. Recent; found at a depth of 1800
fathoms.

Range and Distribution of the Crinoidea.

With the exception of the Comatulidae, all recent Crinoids (Pentacrinus,
Metacrinus, Rhizocrinus, Bathycrinus, Calamocrinus, Hyocrinus, Holopus) are deep-
sea inhabitants ; and in many instances our knowledge of them is based upon
but a few sporadic specimens. Of the Comatulidae, over 200 recent species
have been described, the majority of which are found either in literal zones,
or in comparatively shallow water.

Crinoids attained their maximum development during the Palaeozoic era.
The three principal orders — the Larmformia, Camerata, and Fistulata — are
wholly confined to the Palaeozoic rocks; and with the exception oiMarsupites
and Uintacrinus, the same is also true of the FlexiUlia. The Articulata, on
the other hand, appear first in the Trias, and are represented continuously
up to the present time. On this account Carpenter separated the Mesozoic
and Cenozoic forms, under the term Neocrinoidea, from all earlier Crinoids,
the latter being designated as Palaeocrinoidea. This distinction, however, has
been shown to be largely artificial, and is now generally abandoned.

Crinoids, as a rule, have but a very local distribution ; but in certain
formations detached stem-joints and other fragments occur so profusely as to
become of considerable rock-building importance; strata amounting to a
number of metres in thickness are occasionally met with, which are almost
wholly constituted of Crinoid remains.

While the great majority of recent forms are deep-sea inhabitants, the
Palaeozoic, on the contrary, often characterise shallow water deposits, and
are especially numerous in the vicinity of fossil coral reefs. Of the Mesozoic
Crinoids, the Eugeniacrinidae and Plicatocrinidae, whose remains are commonly
associated with those of Hexactinellid and Lithistid Sponges, probably lived
at considerable depths ; while, on the other hand, iheJEncrinidae, Apiocrinidae,
Saccocomidae, and Pentacrinidae, were undoubtedly shallow water forms.

176

ECHIXODERMATA— PELMATOZOA

SUB-KINGDOM III

TABLE SHOWING THE VERTICAL RANGE OF THE CRINOIDEA.

Families.

Cambrian.

1
1

Silurian.

Devonian.

Carboniferous.

Permian.

i

d

I-B

Cretaceous.

b

1

Recent.

1. Larviformia

1. Haplocrinidae
2. Allagecrinidae

3. Pisocrinidae

4. Symbathocrinidae
5. Cupressocrinidae
6. Stephanocrinidae

2. Camerata
1. Platycrinidae
2. Hexacrinidae
' 3 Actinocrinidae

___

_^

4. Barrandeocrinidae
5. . Reteocrinidae

6. Thysanocririidae
7. Rhodocrinidae
8 Melocrinidae

— _~

9. Calyptocrinidae
10. Crotalocriuidae

3. Fistulata
1. Hybocrinidae
2 Anoroalocrinidae

— ^»—

-^ -

3. Heterocrinidae
4. Belemnocrinidae
5. Catillocrinidae
6. Calceocrinidae

— ^^^

~— "

.^— —

-

7. Gasterocomidae

8. Cyathocrinidae
9. Poteriocrinidae
10 Acrassizocrinidae

—

...?...

4. Flexibilia
1. Ichthyocrinidae

2 Marsupitidae

3 TJintacrinidae

5. Articulata

2 Apiocrinidae

3. Bourgueticrinidae

4. Eugeniacrinidae
5 Holopidae

6. Plicatocrinidae

7. Saccocomidae
8 Pentacrinidae

"

9. Comatulidae

CLASS ii CYSTOIDEA 177

Crinoidal fragments have been detected in the Cambrian, but consist of
stem-joints only (Dcii'/m'-rimis). The Ordovician of England also yields a
\urirty of stem-joints, and well-preserved calices of Hybocrinus and Baerocrinus
occur in rocks of the same age in the vicinity of St. Petersburg. In North
America, also, the Trenton and Hudson River limestones are locally very
rich in Crinoid remains. The Silurian localities of Dudley and Wenlock,
England, and especially the island of Gottland, Sweden, are famous for the
surprising abundance and exquisite state of preservation of their fossil
Crinoids. The Swedish forms alone comprise 43 genera and 176 species.
The Silurian of North America, notably the Niagara Group, likewise
contains a large variety of forms.

The best known Devonian localities are the Eifel, Rhineland, Nassau, West-
phalia, the Ardennes, Asturias, Departement Mayenne, and North America.
The Carboniferous Limestone of Tournay and Vise", Belgium, and that of Eng-
land, Ireland, and the vicinity of Moscow, Russia, is occasionally charged with
exceptionally well-preserved Crinoidal remains. But the most famous of all
horizons is the Sub-CarboniferouS Limestone of North America, where, in
particular, the localities of Burlington, Iowa, and Crawfordsville, Indiana,
have acquired a world- wide reputation.

The Permian has yielded but a single genus, which is doubtfully referable
to Cyathocrinus. From the Trias only the Encrinidae and a few species of
Pentacrinus are as yet known. The remaining members of the Articulata
make their appearance in the Jura and Cretaceous, and with the exception of
the Saccocomidae, are still represented in the existing fauna.

Class 2. OYSTOIDEA. Leopold von Buch.1

Extinct, pedunculate, or more rarely stemless Pelmatozoa, with calyx composed of
more or less irregularly arranged plates. Arms imperfectly developed, sometimes absent.
Calyx plates often finely perforate.

The calyx is globose, bursiform, ovate, or ellipsoidal in form, more rarely

1 Literature:

Volborth, Alex, von, Ueber die Echinoencrinen (Bull. Acad. Imp. Sc. St. Petersb. vol. X.), 1842.
Volborth, Alex, von, Ueber die russischen Sphaeroniten (Verhandl. Mineralog. Gesellsch. St.

Petersb.), 1845-46.
Buch, Leopold von, Ueber Cystideen (Abhandl. der Berliner Akad. fiir 1844), 1845. Translated

in Quart. Journ. Geol. Soc. London, 1845.
Forbes, Edward, On the Cystidea of the Silurian Rocks of the British Islands (Mem. Geol. Survey

Great Brit. vol. II., part 2), 1848.

Miiller, Johannes, Ueber den Bau der Echinodermen (Abhandl. der Berliner Akad.), 1853.
J/n/f, Jtnnen, Palaeontology of New York, vol. II., 1852, and vol. III., 1859.
Billings, E., On the Cystidea of the Lower Silurian Rocks of Canada (Figures and Descriptions of

Canadian Organic Remains, Decade III.), 1858.
Hall, James, Descriptions of some new Fossils from the Niagara Group (20th Ann. Rept. N.Y.

State Cabinet of Nat. Hist.), 1867.
Billings, E., Notes on the Structure of Crinoidea, Cystidea, and Blastoidea (Sil. Amer. Journ.

Sci. 2nd ser.), vol. XLVIII., 1869, and XLIX., 1870.
Volborth, Alex, von, Ueber Achradocystites uud Cystoblastus (Mem. Acad. Imp. Sci. St. Petersb.,

vol. XVI.), 1870.
Schmidt, Fr., Ueber Baltisch-Silurische Petrefacten (Mem. Acad. Imp. Sci. St. Petersb., vol.

XXI.), 1874.

Barrande, Joachim, Systeme Silurieu du Centre de la Boheme. Cystidees, vol. VII., 1887.
Carpenter, P. H., On Certain Points in the Morphology of the Cystidea (Journ. Linn. Soc. vol.

XXIV.), 1891.

VOL. I N

178

ECHINODERMATA— PELMATOZOA

SUB-KINGDOM III

cylindrical or discoidal, and is composed of quadrangular, pentagonal, hexa-
gonal, or polygonal plates, which are united by close suture. The plates
vary in number from thirteen to several hundreds, and only exceptionally
exhibit a regular arrangement. Sharp demarcations between the actinal and
abactinal systems of plates, and between radial and interradial areas rarely
exist ; the plates of the sides of the calyx pass insensibly into those of the
ventral surface, and are disposed in regular cycles only in a few instances.
The base, however, is composed of a distinct ring of plates, and is usually
recognisable by the presence of an articular surface for the attachment of a
stem, or by being directly adherent to some foreign object.

The mouth is indicated by a central or subcentral aperture on the upper
surface. It is sometimes covered by five small plates corresponding to the
orals of Crinoids, and from it radiate from two to five simple or branching
ambulacral grooves. The second opening on the ventral surface is situated
eccentrically, and is frequently closed by a valvular pyramid, consisting usually

of five or more triangular
plates ; or the covering
may consist of a variable
number of smaller pieces.
This aperture, which was
regarded by L. von Buch,
Volborth, Forbes, and
Hall as a genital open-
ing, is now generally
conceded to represent
the anus. A third smaller
opening, situated be-
tween the mouth and
the anus, is present in a
few forms only. The
functions of this latter
a, Aristocystites. Sub- orifice are not well un-

tegminal ambulacral ^ . .

rooves; &, Same of derstOOQ, but it IS COm-

llarged monly regarded as the
ovarian aperture, or genital
pore (Fig. 292) Yet another small, slit-like opening, situated in the vicinity
of the mouth, was detected by Barrande in the genus Aristocystites ; but its
functions are altogether unknown.

The ambulacral grooves, which are present in most Cystideans, are usually
simple, although sometimes distally branching, and are frequently roofed
over by alternately arranged covering pieces. In a few forms (Caryocrinus,
Cryptocrinus, etc.) the grooves are wholly absent. The genera Aristocystites,
Pyrocystites, and Craterina are without exposed ambulacral grooves ; but they
have instead, as Barrande discovered, a peculiar system of five or six covered
passages on the inner surface of the calyx plates, which converge towards the
mouth, and are distally more or less branching (Fig. 293). These structures,
the so-called " hydrophores palme'es" were homologised by Barrande with the
hydrospires of Blastoids ; but as Neumayr has pointed out, they are probably
the equivalent of subtegminal food-grooves in Crinoids.

The calyx plates exhibit most remarkable structural peculiarities. As a

FIG. 292

Glyptosphaerites Leuchtenbergi, Volborth.
Calyx showing ambulacral grooves, plated
mouth-opening, large laterally situated anus,
and small ovarian aperture between mouth
and anus.

Pyrocystites.
(after Barrande).

CLASS II

CYSTOIDEA

179

rule they are more or less extensively perforated by pores or fissures ;
although in some forms (Cryptocrinus, Malocystites, Ateleocystites, etc.) they
appear to be imperforate, and are composed of a homogeneous calcareous
layer of greater or lesser thickness, the same as in Crinoids. But in Aristo-
cystites, Craterina, Proteocystites, Glyptosphaerites, Echinosphaerites, etc., the plates
are uniformly covered both externally and internally with
a very thin, generally smooth, calcareous membrane, which
may be perforate or imperforate. The central layer is of
variable thickness, and is traversed by numerous canals
(Figs. 294, 295) which extend from the inner to the outer
surface, sometimes rectilinearly (Aristocystites, Craterinera, perforating the median

,.•,„.! . «. , . layer of plate.

etc.) ; sometimes in slightly sinuous lines ; and in rare
instances they divide dichotomously. The canals terminate on either surface
in small round apertures or pores, which are arranged either singly or in
pairs, and may or may not penetrate the outer calcareous membrane. The
pores are commonly situated either on a tubercular elevation, or in a slight
superficial depression.

But still more frequent than the canals are the so-called pore-rhombs (Fig.
296) which occur indifferently in types possessing numerous or but few
calycine plates. The pores are arranged so as to form lozenge-shaped or
rhombic figures, in such manner that one half of each rhomb belongs to one

Fio. 295.

<!ncystites. Inner surface of
two calyx plates showing simple
pores; 6, Glyptosphaerites. Outer
surface of calyx plate showing double
pores.

Pore-rhombs of (a) Echinosphaerites, and 6, Car?/".
enlarged. The left half of Fig. a is abraded, so that the con-
necting tubes appear as open grooves.

plate, and the other half to its contiguous neighbour ; while the line of suture
between the plates forms either the longer or the shorter diagonal of the
rhomb. The pores of opposite sides of the rhomb are united by perfectly closed,
straight ducts, which pass horizontally through the middle layer and across
the line of suture between the two plates, thus producing a transversely
striated appearance. Occasionally the connecting tubes appear on the outer
surface as elevated striate rhombs ; but as a rule they are concealed by the
above-mentioned covering layer, and are only visible' in weathered or abraded
specimens. The pores of the rhombs also communicate with short canals
passing vertically through the plates, the ends of which are either covered
over by the outer calcareous layer, or appear on both surfaces as fine indepen-
dent pores. A pair of oppositely situated pores of the latter description
may sometimes receive as many as two or three fine canals, while in other
genera they are entirely wanting.

The pore-rhombs are sometimes present upon nearly all plates of the calyx,
but in other cases they are only developed on a certain number or on all of

180 ECHINODERMATA— PELMATOZOA SUB-KINGDOM in

the plates forming the side- walls of the calyx, being absent from its upper
surface. In still other instances (Pleurocystites, Callocystites), (Fig. 297), the
pore-rhombs are greatly reduced in number, and occur in the form known as
"pectinated rhombs." The component halves of the latter stand on contiguous
plates the same as the ordinary pore -rhombs, but are always separated
externally by an interval ; frequently the two parts are of different form or
size, and sometimes one of them may become obsolescent.

As regards the functions of these canals and pores (the " hydrospires " of
Billings), the anatomy of existing Crinoids furnishes us with no positive con-
clusions. They have been compared with the pores which are present in the

tegmen of the . latter, and
the rather plausible sugges-
tion has been offered that
they served to admit water
into the body -cavity, and.
thus performed respiratory
functions. At all events,
they could not have served
for the protrusion of tube-
feet, since they are fre-
quently covered over by an
FlG- 297- outer calcareous membrane,

Callocystites Jewetti, Hall. Silurian (Niagara Group); Lockport, whip}, pffppfnall v <5>inf<? off

New York. A, Calyx from one side (natural size). B, Ambulacral wm tuaiiy SHI

grooves and three pectinated rhombs (rh), enlarged ; o, Mouth ; communication with the
an, Anus ; g, Genital pore (after Hall).

exterior.

The arms in the Cystideans are but feebly developed, and are sometimes
entirely (1) wanting, or they are but few in number (2, 3, 6, 9-13). The pent-
amerous symmetry, so generally characteristic of Echinoderms, pervades neither
the arrangement of the calyx plates nor the number and disposition of the
arms. The latter are invariably simple, are either uniserial or biserial, and
exhibit a ventral groove protected by covering plates.

In some genera the arms attain considerable thickness, but in others they
are very diminutive, and seem to have closer affinities with pinnulae than with
the arms of Crinoids. In the Callocystidae and Agelacrinidae, as well as in the
Canadian genera, Amygdalocystites and Malocystites, the arms either recline with
their dorsal side facing the calyx, or they are incorporated into the calyx.
The ventral side, in these cases, is directed outwardly, and the ambulacral
furrow is bordered on either side by a row of alternating, jointed pinnules,
which are attached by small articular facets running parallel with the
groove. Pinnules have not as yet been observed in Agelacriiws, but the
allied genera, Mesites and Asteroblastus, are furnished with delicate facets for
their attachment.

The stem, as a rule, is greatly abbreviated, and is frequently obsolete.
Sometimes the calyx is attached by the entire lower 'surface (Agelacrinus) ; or
in other cases by means of a tubercular process (Echinosphaerites). Only in
rare instances does the stem appear to have served for attachment, since it
generally tapers dis tally to a point, and is invariably destitute of cirri. The
stem sometimes resembles that of the Crinoids, in being composed of a number
of short, prismatic, or cylindrical joints ; these are pierced by a wide canal,
and are either united by horizontal, striated, articular surfaces, or they over-

CLASS n ('YSTOIDEA 181

st ri.le one another like the draw-tubes of a spy-glass. In other cases the upper
part, and occasionally, indeed, the entire stem, is composed of vertical rows of
alternating plates. These plates, as a rule (Dendrocytiites), enclose a large
..•titial space, which may be regarded as a prolongation of the body-cavity. .

The Cystideans constitute the oldest and least specialised group of the
Pelmatozoa. Appearing first in the Cambrian, they develop a great variety of
forms in the Ordovician and Silurian, but become extinct before the close of
the Permian. While their own ancestry is obscure, it is highly probable that
from them have descended both the Crinoids and Blastoids. If, on the one
hand, the Aristocystidae, Spliaerodontidae, Camarocystidae, and Echinosphaeritidae
differ radically from the Crinoids in respect to their numerously and irregularly
plated calyx, or as regards the feeble development or even total absence of
their arms ; nevertheless, the Cryptocrinidae and the unfortunately ill-preserved
Cambrian genus, LicJierwides, evince a striking similarity, especially as concerns
the more or less regular arrangement of the calyx plates, and a certain approach
to radiation. In fact, so far as the construction of the calyx alone is concerned,
forms like Porocrin-us and Hypocrinus may be assigned with equal propriety to
. it her the Crinoids or Cystids. The presence of pectinated rhombs and
calycine pores, however, and the porosity of the calyx plates, are characters
which positively identify them as belonging to the latter class.

If we can account for the derivation of Crinoids from the Cystideans on the
supposition that the calyx plates of the latter gradually took on a more
definite arrangement, while the loss of pores and pore-rhombs was counter-
balanced by a stronger development of the arms and the stem ; so, too, it is
possible to explain the origin of the Blastoids from the same source. Although
hydrospires are clearly wanting in the Cystids, nevertheless, other characters,
such as the recumbent attitude of the arms upon the sides of the calyx, or
their insertion in grooves on the ventral surface, as well as an approach to
ambulacra! areas in certain forms (Asteroblastus), predicate an intimate relation-
ship with the Blastoids. Probably the most notable similarities are presented
by the peculiarly modified families, Callocystidae and Agelacrinidae. Various
attempts have been made to affirm a connection between Agelacrinus and the
Astero&ka, and between Mesites and certain of the primordial Echinoidea (Cysto-
'/"/v'.s); but such hypotheses are scarcely warranted, since they proceed from
an over-valuation of mere external resemblances, which are in nowise indicative
of kinship.

The classification of the Cystoidea remains in a very unsatisfactory condition.
This is owing in part to' the comparative scarcity of material, as well as its
frequently imperfect state of preservation ; and in part to our insufficient
understanding of many of the structural modifications. The classification of
Johannes Miijler was based primarily upon the structure of the calyx plates,
and three main groups were recognised : — Aporitidae, Diploporitidae, and Rhombi-
/'•/•/. These divisions, however, embrace a number of very heterogeneous
elements, and in nowise fulfil the requirements of a natural system. The
classifications proposed by Barrande and Steinmann are still more inadequate.
It is advisable, therefore, to follow the example of Neumayr and Bernard, and
merely arrange the different genera into families ; the establishment of larger
divisions being deferred until the group shall have been monographed.

182

ECHINODERMATA— PELMATOZOA

SUB-KINGDOM III

Family 1. Aristocystidae. Neumayr.

Calyx composed of numerous heavy plates, arranged either irregularly or in suc-
cessive zones, and covered on both sides by a calcareous integument. Calyx plates
traversed by simple canals terminating on either surface in pores distributed either singly
or in pairs. Ambulacral grooves subtegminal (" hydrophores palme'es ") • arms want-
ing ; stem obsolete or very short. Ordovician.

Aristocystites, Barr. (Fig. 298). Calyx bursiform or ovate; ventral surface
with four apertures. Ordovician (Etage D) ; Bohemia.

Deutocystites, Barr. Ventral surface with three apertures. Craterina, Barr.
Conical, truncate. Pyrocystites, Barr. Clavate in form. All three genera in
Ordovician (Etage D) of Bohemia.

FIG. 299.

Glyptosphaerites Leuchtenbergi, Volborth. Ordovician ; St. Petersburg.
a, Calyx seen from above (natural size); b, Same from the dorsal face, with
stem attached, reduced 1/2 (after Volborth) ; c, Calyx plates showing double
pores (enlarged).

Aristocystites Jiohemir.us, Barr.
Ordovician (I'd4) ; Zahorzan,
Bohemia, a, Side view ; b, Sum-
mit aspect (after Barrande).

FIG. 300.

Protocrinites oviformis, Eichwald. Ordovician ; Pulkowa, Russia.
*, Calyx viewed from above ; b, Same from below (after Volborth).

Family 2. Sphaeronitidae. Neumayr.

Calyx globular or cylindrical, short-stemmed or stemless, and composed of numerous
irregularly arranged plates with pores united in pairs. AmbulacraL grooves either
open or protected by covering plates, and either short and simple, or elongated and
branching. Arms as a rule exceedingly small and primitive. Ordovician and
Silurian.

Sphaeronites, Rising. Globose, stemless. Five short ambulacral grooves

GLASS ll

CYSTOIDEA

183

radiating from the mouth towards the arm bases. Ordovician (Vaginaten-
kalk) ; Russia, Sweden, and England. S. pomum, Gyll.

Glyptosphaerites, Mull. (Fig. 299). Differs from the preceding in having
long, branching, ambulacral grooves, and a short, well - developed stem..
Ordovician ; Russia and Sweden.

Protocrinites, Eichw. (Fig. 300). Nearly hemispherical, non-pedunculate.
Ambulacra grooves long and branching ; arms unknown. Ordovician ; Russia.

Fungocystites, Barrande. Clavate. Ordovician (Etage D) ; Bohemia.

Proteocystites, Barrande. Devonian (Etage F) ; Bohemia.

Holocystites, Hall (Megacystites, Hall). Elongated, cylindrical, or sub-
cylindrical ; short -stemmed or stemless ; with subcentral mouth. Arms
minute, springing from the ends of the ambulacral grooves. Silurian ; North
America, Gottland.

Eucystis, Angelin. Ordovician. Gomphocystis, Hall. Silurian.

Family 3. Camarocystidae. Barrande.

Calyx globose or discoid, composed of numerous polygonal plates, and sometimes
fixed by tlie ventral surface. Interior of calyx divided into four to six compartments
fit/ /HI rfif ions corresponding in position to lobes on the exterior. Stem long and slender.
Silurian.

This family embraces two genera whose systematic position is still doubt-
ful. The larger, Camarocrinus, Hall ( = Lobolithes, Barrande), occurs in the
middle and upper members of the Silurian in North America and Bohemia,
and attains considerable size. The smaller, Lichenocrinus, Hall, is more or less
crateriform, has a very long, tapering stem, and is invariably attached by its
flattened ventral surface. It is found in the Ordovician (Hudson River
Group) of North America.

Family 4. Echinosphaeritidae. Neumayr.

Calyx globular or bursiform, adherent or with short stem, and composed of
numerous, irregularly arranged plates, all of which are furnished with pore-rhombs.

FIG. 301.

l-j-h ! nnsphaerites aurantium, Hising. sp. Ordovician (Vaginatenkalk) ; Pulkowa, Russia, a, Summit view of
c.-ilyx ; >i. Calyx swn from the anal side; c, Mouth, arms, and covered ambulacral grooves; d, Calyx plates
enlarged, showing pore-rhombs (cf. Fig. 296).

Ambulacral grooves short ; arms two to five, free, Userial, rarely preserved. Stem,
when present, composed of several vertical series of alternately arranged plates.
Ordovician and Silurian.

Echinosphaerites, Wahlenb. (Fig. 301). Globose, non-pedunculate. Mouth
central, ambulacral grooves short. Anal opening protected by valvular

184

ECHINODERMATA— PELMATOZOA

SUB-KINGDOM III

pyramid ; arms unknown. Very abundant in the Ordovician of Russia and

Scandinavia. E. aurantium, Rising, sp.

Arachnocystites, Neumayr. Like the preceding, except
that it has strong arms, usually three in number, which
sometimes attain a length of 10 cm. Stem tapering distally
to a point. Ordovician (Etage D) ; Bohemia. A. infaustus,
Barr. sp.

Caryocystites, v. Buch (Fig. 302). Calyx plates relatively
large. Pore-rhombs on external surface elevated, prominent.
Stem wanting. Ordovician ; Russia, Scandinavia, England.

C' 9™natum, Wahlenb.

Owciistites, Barrande. Ordovician (Etage D) ; Bohemia.

„ , ... -T>MT n i T

Palaeoct/stites, Billings. Calyx ovate or pyriform ; plates
numerous, and poriferous at the margins. Ordovician ;
Canada.

grana-

turn, wahib. sp. Or-

dovician ; Oeland.

Plates of the natural
elevated

Calyx composed of
regularly arranged plates,
attachment of small arms.
to Permian.

Family 5. Cryptocrinidae. Zittel.

rings of very finely perforate or imperforate, somewhat
Mouth central, surrounded by articular facets for the
Anus eccentric; stem round and slender. Ordovician

Cryptocrinus, v. Buch (Fig. 303). Base composed of three plates, and sur-
mounted by two zones, each containing five plates of unequal sizes. Mouth
and anus enclosed within a
ring of smaller pieces. Ordo-
vician ; St. Petersburg. C.
cerasus, v. Buch.

Echinocystites, Hall. Or-
dovician ; North America.

Porocrinus, Bill. (Fig.
304). Base composed of
three plates, and succeeded
by two circlets of regularly
alternating pieces. Upper

Cycle giving rise to five

feeble, uniserial arms. Small

from above, and from below

FIG. 303.
Cryptocrinus cerasus, v. Buch.

fur-

a, Porocrinus conicus, Billings.
Ordovician ; Ottawa, Canada.
Nat. size (after Billings) ; 6, P.
riiilicitus, Beyr. Ordovician ; St.
Petersburg. Calyx plates show-
ing pectinated rhombs. Consider-
ably enlarged (after Beyrich).

supplementary pieces _- (nat size); m>Mouth. fl> Anus
nished with pore-rhombs in-
tercalated in the re-entrant angles between the calyx plates. Ordovician ;
Canada, Russia.

Hypocrinus, Beyr. Base composed of three plates, and succeeded by two
zones of alternately arranged, perforate plates. Mouth central. Permian ;
Timor.

Family 6. Oaryocrinidae. Bernard.

Calyx composed of a moderate number of plates exhibiting a more or less definite
arrangement in cycles. Certain or all of the side plates with pore-rhombs ; those of
the ventral surface imperf orate. Arms three to thirteen, free, feeble. Stem constantly
present, occasionally long. Ordovician and Silurian.

CLASS II

CYSTOIDEA

185

If.micosmites, v. Buch. Calyx composed of four basal plates two zones
,ontainin- six and nine lateral plates respectively, and a circlet of six plates
forming the rented rarfcee. The latter carries three short ambulacral
grooves, at the ends of which are situated small articular facets for the
attachment of arms. Rhomb-pores present on all of the side plates.
vi.-ian : Russia. H. /»///•//'»/•//»*, v. Buch.

Btt^m'/ms- Say (Fi- 305). Calyx hexameroui, with dicyclic base.
Infrabasals four, un.-Mual; followed by a second row (basals) of i ;es,

alternating with
the plates of the
first and third
cycles. The latter
ring consists of
eight plates, six

of which, arc.. fd ^BBsrsv i^me^m >>

ing to Carpenter,
represent the
radials, and two
(the interscapu-
lars of Hall) the
interradials. Ven-
tral surface
formed of six or
more small pieces.
All plates of the
cup furnished

with pore-rhombs ; the summit plates imperf orate. Mouth and ambulacral
grooves subtegminal. Anus protected by valvular pyramid, and situated on
the outer margin of the ventral surface. Here also are placed the arms, which
are six to thirteen in number, and relatively feeble. Stem long, composed of
cylindrical segments. Silurian ; North America (New York and Tennessee).

Echinoencrinus, v. Meyer (Sycocystites, v. Buch), (Fig. 306). Calyx com-
posed of four basal plates, and three cycles containing five plates each. All
calycine plates ornamented with costae or ridges radiating outward from the
centre. Ventral surface with short ambulacral grooves, and articular facets
for the attachment of three small arms. Anus removed to a lateral position
between the first and second circlet of side plates. Three pore -rhombs
present ; of these, two are situated above the base on the side opposite the
anus, and the third above and slightly to the right of the anus. Stem round,
short, tapering distally to a point, and composed of hollow segments inserted
one within the other like the draws of a spy-glass. Ordovician ; Russia.

Glyptocystites, Billings. Ordovician ; Canada and Russia.

Homocystites, Mimocystites, Barrande. Ordovician ; Bohemia.

Family 7. Anomalocystidae. Woodward.

Calyx more or less compressed, frequently with dissimilarly plated anterior and
posterior sides. Plates either imperf orate or with simple pores ; pore-rhombs absent or
but few in number. Arms free ; stem short, tapering distally to a point. Cambrian
to Silurian.

FIG. 305,
ornatus, Say. Silurian ; Lockport, New York.

«, CaTyx from one side, with two arms attached ; b, Summit,
natural size ; c, Inner and outer surfaces of calyx plate of the
second circlet, with pore-rhombs.

FIG.

Echinoencrinus
striatus, v. Buch.
Ordovician ; St.
Petersburg, i

186

ECHINODERMATA— PELMATOZOA

SUB-KINGDOM III

Trochocystites, Barr. Calyx strongly compressed. Plates of the right and
left sides large, those of both the anterior and posterior small, polygonal.
All plates perforate, but without pore-rhombs. Ventral surface with three

apertures. Stem com-
posed of several vertical
rows of plates. Cam-
brian ; Bohemia, Spain,
Northern France.

Mitrocystites, Barr.
Like the preceding, ex-
cept that one side of the
calyx is composed of toler-
ably large, and the other
of small plates. Ordo-
vician ; Bohemia.

Anomalocystites, Hall
(Aeteleocystites, Bill.)
Calycine plates smaller
and more numerous on
th *rl +- Vi

tn6 convex sicie than
the COncave AnUS

Pleurocystites squamosus, Billings. Ordovician ; Ottawa, Canada.
a, Calyx from the anterior side ; b, Same from the ^anal side ; c, Arms,
enlarged. Right and left reversed (after Billings). '

on

, , ,

situated very low down
on the convex side. Arms feeble, filiform. Ordovician and Silurian ; North
America, England, Bohemia.

Balanocystites, Dendrocystites, Barr. Ordovician ; Bohemia.

Pleurocystites, Bill (Fig. 307). Convex side with large plates arranged
in cycles ; flattened side covered with very minute plates. Three isolated
pore-rhombs borne on the convex side. Arms two in number, robust. Stem
round, tapering distally to a point. Ordovician ; Canada.

FIG. 308.

Pseudocrinites quadrifasciatus,
Pearce. Silurian ; Tividale, Eng-
land. A, Calyx from one side.
B, Summit, showing mouth (m), anus
(a), and three of the arms. The
fourth arm (x) broken away, exposing
flattened surface of calyx.

FIG. 309.

Callocystites Jewetti, Hall. Silurian (Niagara Group) ; Lockport,
New York. A, Calyx from one side (natural size). JB, Ambulacral
grooves and three pectinated rhombs (rh), enlarged ; o, Mouth ;
an, Anus ; g, Genital pore (after Hall).

Family 8. Callocystidae. Bernard.

Calyx composed of large plates arranged in three or four cycles, and exhibiting
three to five pectinated rhombs, the component halves of which stand on contiguous plates,

CLASS IF

CVSTOIDKA

187

and are separated by an interval. Mouth slit-like, and forming the centre of radia-
tion for two to five pinnulate arms which are protected by covering pieces, and either
repose upon the calyx, or are sunk below the surface in grooves. Stem well developed,
taperiii'/ <H*t<iUij to a point. Ordovician and Silurian.

Pseudocrinites, Pearce (Fig. 308). Calyx ovate, two- to four-sided, and
composed of four cycles of polygonal plates. Anus closed by valvular
pyramid, and occupying a lateral position. Pore-rhombs three in number ;
one placed above the base, the remaining two to the right and left of the
anus. Arms two to four, recumbent upon the calyx, extending to the base,
and beset with biserial jointed pinnules. Stem robust. Silurian; England.

Lepadocrinus, Hall ; Apiocystites, Forbes. Silurian.

Callocystites, Hall (Fig. 309). Calyx with four pore-rhombs. Arms some-
times bifurcating. Silurian ; North America.

? Hybocystites, Wetherby. Ordovician.

Family 9. Agelacrinidae. Hall.

Calyx composed of a large number of small, irregularly arranged plates, and
> if It <r furnished with a short stem, or fixed by a broad base. Plates pierced by pores,
a finally united in pairs. Mouth central; anus eccentric, provided with valvular
jiii rn mid. Arms placed in radial grooves on exterior of the calyx, and protected by
covering plates. Ordovician to Carboniferous.

Agelacrinus, Vanuxem (Fig. 310). Calyx in the form of a depressed or
convex disk, stemless, and attached by the entire under surface ; composed of
numerous, small, polygonal, usually imbricating plates, which are perforated

Fin. 310.

Agelucrinus Cincinnatiensis, Roeinfir.
Ordovician; Cincinnati, Ohio. Indi-
vidual of the natural size adherent to
shell of Strophomena alternata.

FIG. 311.

Asteroblastus stellatus, Eichwald. Ordovician
Pulkowa, Russia. Natural size (after Schmidt).

by fine, and, for the most part, conjugate pores. Mouth surrounded by four
oral plates ; radiating from this are five small, more or less curved arms,
which are embedded in grooves on the outer surface, and are protected by a
double row of covering plates. Ordovician ; North America and Bohemia.
Rare in Silurian, Devonian, and Carboniferous.

Sub -genera: — Lepidodiscus, Hemicystites, Cytaster, Hall; Edrioaster, Billings.
Ordovician; North America.

Mesites, Hoffmann. Globose, with truncate base, probably pedunculate.
Calyx plates small, polygonal, and exhibiting conjugate pores. Arms five,
very small, embedded in radial grooves, arid protected by covering plates ; the
latter are furnished with articular facets for the attachment of pinnules, and

188 ECHINODERMATA— PELMATOZOA SUB-KINGDOM in

are separated by small furrows conducting into the ambulacral grooves. Anus
closed by a valvular pyramid. Ordovician ; Russia, Bohemia.

Asteroblastus, Eichw. (Fig. 311). Calyx gemmiform, pentagonal, pedun-
culate, and composed of innumerable rigidly united plates which are per-
forated by conjugate pores. Upper surface marked by five large petaloid
or stellate areas, which are covered with alternating plates, and correspond
to the recumbent arms of Agelacrinus. Ordovician ; Russia.

Tiaracrinus, Schliit. (Staurosoma, Barr.) Devonian ; Eifel, Bohemia.

Range and Distribution of the Cystoidea.

Not only are the Cystideans wholly extinct, but they also constitute the
oldest known group of the Pelmatozoa. They are represented in the Cam-
brian by a number of poorly preserved forms, whose affinities are in many
cases doubtful (Protocystites, Macrocystella, Eocystites, Lichenoides, Trochocystites)i
They attain the climatf of their development in the Ordovician and Silurian,
whereupon they suddenly diminish in numbers, and with the close of the
Carboniferous they entirely disappear. Of the 250 species that have been
described, scarcely a dozen are found in strata above the Silurian.

Although a few forms (Echinosphaerit&s, Aristocystites, Caryocystites) appear
in considerable abundance in certain formations, and occasionally fill up
whole beds, the majority are of comparatively rare occurrence. The arms
and pinnules are only exceptionally preserved, owing to their fragile con-
stitution ;' and the stem is also usually lost.

Cystideans are found most plentifully in the Ordovician rocks of St.
Petersburg, Russia, and in the Silurian localities of Oeland, Gottland, Sweden,
Wales, and Bohemia (Etage D). The Bohemian specimens are usually pre-
served in the form of casts and moulds, and are contained in silicious or
argillaceous slates. The Chazy and Trenton limestones of Canada, New York,
Ohio, and Indiana also yield a large variety of forms.

Excellently preserved specimens of Pseudocrinites, Apiocystites, Echinoen-
crinus, and Anomalocystites are obtained from the Silurian limestones of Dudley
and Tividale, England ; similar, and in part vicarious forms (Lepadocrinus,
Callocystites, Caryocrinus) being found in the Silurian (Niagara Group) of North
America. Only scanty remains are known from the Devonian (Proteocystites,
Anomalocystites, Agelacrinus, and Tiaracrinus) ; and but two genera (Agela-
crinus and Lepadocrinus) are represented in the Lower Carboniferous. The
last surviving genus is Hypocrinus, which is confined to the Permo-Carbon-
iferous of Timor.

Class 3. BLASTOIDEA. Say.1

Extinct, short-stemmed, or stemless Pelmatozoa with a large rigid calyx, which
resembles a flower-bud in shape, and is generally composed of thirteen principal

1 Say, Thomas, Observations on some Species of Zoophytes, etc. (Am. Journ. Sci. vol. II.), 1820.
Say, Thomas, On two Genera and several Species of Crinoids (Joiirn. Acad. Nat. Sci. Phil ad. vol.

IV. p. 289), 1825. (Also in Zool. Journ. vol. II. p. 311), 1825.
Roemer, Ferdinand, Monographic der fossilen Crinoideenfamilie der Blastoideen (Troschel's Archiv.

fiir Naturgeschichte, Bd. XVII. pp. 326-397), 1852.
Rofe, John, Notes on Echinodermata (Geol. Mag., Dec. 1, vol. II.), 1865.

CLASS nr

BLASTOIDEA 189

plates ; with recumbent ambulacra, which suppoii at tlieir lateral margins numerous
/linn iila-like appendages, and are provided along their inner floor with lamellar tubes
1: a n im as hydrospires.

The calyx is da vat r, pyriform, ovate, or globose, frequently pentangular
at its upper face, and composed of plates which are firmly united among
themselves. The plates of the abactinal system are arranged in three suc-
cessive cycles, represented by the basals, radials, and interradials. The
plates of the actinal system comprise the summit plates and the ambulacra.

The basals consist of two plates of equal size, and a third smaller one,
which is directed invariably toward the right anterior interradius. Resting
upon the basals are five V-shaped, usually equal radials (commonly known
as "forked plates"), whose superior margins
are more or less deeply incised by the radial
sinuses. The term sinus is applied to the open
space between the two prongs or limbs of the
plate.

Succeeding and alternating with the radials,
and resting upon their limbs, are five interradial
or deltoiil /ilnfi's, which vary excessively in size.
In some species they occupy a large part of the
sides of the calyx, and in others they are confined
to the upper face. In Elaeacrinus and certain
species of Granatocrinus, the deltoids extend down
so far into the calyx as to constitute more than FlG 312

half, or nearly the whole of its sides, while the Pentremttes Godoni, Defr. sp. Dia-
radials are so short as to be almost invisible in a fJ^iJj^SiSs mS&SSi ' ' Radials ;
side view. Most writers refer the deltoids to the

plates of the tegmen, but they properly form a part of the dorsal cup. Only
a part of the deltoids is exposed to view, their sides being provided with
flanges which are covered by the proximal ends of the ambulacra. The name
deltoid has reference to the exposed part of the plates, which in most forms is
triangular or rhomboidal in outline.

The radial sinuses between the limbs of the radials and the superjacent
deltoids are filled by the ambulacral fields or ambulacra ("pseudoambulacra" of
Roemer). The ambulacra vary in form from petaloid to narrow lanceolate or
linear, and extend from the summit of the calyx to the distal ends or lips of
t'he radial sinuses. The open space in which the ambulacra meet, the so-called
"summit-opening," is pentangular, and central in position. Ordinarily this
space is unobstructed, but in well-preserved specimens it is covered by a
greater or lesser number of minute calcareous pieces (Fig. 313) ; these may be
either regularly or irregularly arranged, but leave at each angle of the summit-
opening a small passage-way, by means of which the ambulacra communicate
with the peristome. The mouth is invariably subtegminal.

[The summit structure is rarely observed. The covering in Elaeacrinus
consists of five asymmetrical orals ; similar orals, surrounded by smaller plates,
are present in Orophocrinus, and in Schizoblastus Sayi ; but in Granatocrinus

Billings, E,, Notes on the Structure of Crinoidea, Cystidea, and Blastoidea (Am. Journ. Sci. 2nd.

ser. vols. XLVIII., XLIX., and L.), 1869-70.
Ether idge, R., and Carpenter, P. H., Catalogue of the Blastoidea in the Geological Department of

the British Museum, 1886. [Complete bibliography, pp. 303-310.]

190

ECHINODERMATA— PELMATOZOA

SUB-KINGDOM III

Norwoodi and in Cryptocrinus melo, the summit is paved by numerous, very
minute, irregularly arranged pieces. In the genus Pentremites, as observed in
five or six species, the summit is surmounted by a pyramid formed of five
elongate, tapering spines, the outermost of which are shorter than the rest.
This pyramid not only conceals the summit-opening, but also extends over
the greater part of the spiracles and the anal aperture ; , but it leaves at

FIG. 313.

A, GranMocrinus Norwoodi, O. and S. Upper face of perfect specimen, with mouth and anus (a) closed by
plates. Spiracles (sp) separate. B, Orophocrinus stelliformis, O. and S. Upper face with closed peristome and
exposed anus. Spiraoles slit-like. C, Pentremites sulcatus, Roem. Central mouth-opening surrounded by five
spiracles, the posterior one confluent with the anus. D, Cryptoblastus melo, O. and S. sp. Upper face with
central mouth-opening, large anus, and eight spiracles (after Carpenter).

the median line of each ambulacrum a channel communicating with the

peristome.]

The summit in most Blastoids is surrounded by a cycle of five pairs of

openings ; and between the two posterior ones there is usually interposed

a single additional aperture.
The former were regarded by
Roemer as connected with the
genital system, and were
called by him "ovarian aper-
tures"-, but they are now
known as the spiracles. The
other opening which pierces
the upper end of the posterior
deltoid is the anus.

The form and arrange-
ment of the spiracles is ex-
FlG 314 tremely variable ; they may

A, Pentremites Godoni, Defr. sp. Upper face with ambulacral be round Or slit-like ; they

fpn cpnnrni-P

fields in various states of preservation, a, Ambulacrum after the ^aw nrmoi'0t

removal of lancet- and side-plates ; hydrospires exposed ; b, Lancet- mav (

plate with upper surface denuded by weathering ; c, Perfectly pre- openings, Or those of the Same

served lancet-plate bordered by side-plates ; d, The same, but with . , - -,

transverse markings of lancet-plate obliterated ; e, Ambulacrum pair may be Confluent With One

covered with pinnules (after Roemer). B, Phaenoschisma aculum, - 1 i ,r

Sow. sp. Upper face, enlarged ; a, Ambulacrum after removal of another ; and tile posterior

the lancet- and side-plates; hydrospire slits (hy) cutting through r,ojr T^OTT V>P fns-prl both with

radials and deltoids ; b, c, Ambulacra in which lancet-plates (Q only Pair may D<3 1USe.C

are preserved ; d, e, Ambulacra intact ; lancet-plate concealed, by each Other and with the anUS

side-plates (after Etheridge and Carpenter). . -i • i , i nr.-t

in which case the fifth or

posterior spiracle is considerably larger than the others. Granatocrinus,
Pentremites, Pentremitidea, etc. (Fig. 314, A), are examples of the latter case;
Granatocrinus having five circular orifices with tube-like projections, while in
Pentremites and Pentremitidea the four smaller spiracles are divided into two
compartments by the terminal median ridge of the deltoids. The posterior

CLASS III

BLASTOIDEA

191

spiracle in the two latter genera is divided by a duplicate ridge into three
compartments; of these the middle one enters the inner cavity, and the two
outer ones communicate with the hydrospires by means of the hydrospire
canal. In Troostocrinus, Schizoblastus, and Cryptoblastus (Fig. 313, D) the
posterior spiracles are confluent with the anus, while those of the four regular
sides are separated. Elaeacrinus, Mesoblastus, and Acentrotremites have ten
separate spiracles, and a large, distinct anal aperture. The typical Codasteridae
(Cadaster and Fhaenoschisma), in which the hydrospires are exposed externally,
have no spiracles and no hydrospire canal. Orophocrinus (Fig. 313, B) has
ten elongate clefts extending along the sides of the ambulacra ; but these are
in reality the unclosed portions of the radial sinuses, and correspond to the
open hydrospire canals of Pentremites, which are apparent upon the removal of
the side-plates.

The ambulacra are usually depressed below the general level of the calyx,
but are sometimes raised above it, or they may be placed in the same plane
with it. They vary in form from narrow A n

linear to broad petaloid, and are considerably
complicated in structure (Fig. 315). The
centre of each ambulacrum is occupied by the
lancet-plate, a long, narrow piece, pointed at
both ends, which extends to the full length of
the fields. Its proximal end is inserted be-
tween the deltoids, and takes part in the lip
around the summit-opening. The upper sur-
face of the plate is excavated along the median
line, and forms an open, well-defined groove,
which conducts to the mouth, and in all prob-
ability represents the food-groove. The in-
terior of the plate is traversed by an axial
canal, which communicates by means of the
ambulacral opening with an oral ring belonging plate (0 ; median food-groove of the same

,, T r (a) ; side-plates (s) ; outer side-plates (e) ;

tO the Water- VaSCUlar System. In a number OI and marginal pores (p). 5/j (after E and

forms (Pentremites, Orophocrinus) there is to ^SffSSSSSS^^ Letter'
be seen a second, smaller, and extremely thin

plate underlying the median portion of the first; this is called the under
hi mrf -plate,.

The lancet-plate rarely occupies the full width of the ambulacral field, and
the spaces between its lateral edges and the sides of the radial sinus are either
wholly or partially covered by a row of small, horizontally elongated side-plates
(" pore-plates" of Roemer). In Pentremites, Orophocrinus, and other genera, an
additional series of still smaller pieces, called the outer side-plates (" supple-
mentary pore-plates" of Roemer), are placed between the side-plates and the
walls of the radial sinus. Pentremites and Cryptoschisma have the entire upper
surface of the lancet-plate exposed to view, and the side-plates are situated
alongside of it in the same plane. But in other forms the lancet-plate is
wholly, or to a very large extent, concealed by the side-plates (Fig. 315, B),
so that as a rule only a small space along the food-groove is' visible. The
sutures between the side-plates are indicated by shallow, horizontal grooves,
which are continued as superficial markings over both halves of the lancet-
plate as far as the median ambulacral groove. These crenulations, it should

FIG. 315.

A, Pentremites pyriformis, Say. Portion
of an ambulacrum, exhibiting the lancet-

192

ECHINODERMATA— PELMATOZOA

SUB-KINGDOM III

be noted, are frequently effaced in weathered specimens (Fig. 315, A and E]>
Small pit-like depressions, or small tubercles, which are observable on the side-
plates, indicate the places where the appendages or pinnules were formerly

attached. These are
\ J^J^L / only exceptionally

completely conceal
the ambulacral fields,
and extend upward
above the summit of
the calyx (Fig. 316).
They vary consider-
ably in length, even
among species be-
gub longing to the same
genus.

In most Blastoids
the side-plates, or
the outer side-plates
when such are present, are pierced by marginal pores (or hydrospire pores), which
communicate with the hydrospires. The pores are situated at the extreme
outer margins of the plates, at the end of the lateral ridges, and alternate in
position with the sockets of the pinnules. They are present in all forms,

FIG. 316.

a, Pinnule of Pentremites, enlarged ;
b, Granatocrinus Norwoodi, O. and S.,
with perfectly preserved pinnules (after
Meek and Worthen).

Trans-

Pentremites sulcatus,
Carboniferous ; Illinois
verse section of calyx at about 1/3
the height of the ambulacral fields.
X 1 !/2- hy, Hydrospires ; I, Lancet-
plate ;" p, Pore-plates ; r, Radials.

Transverse sections through the ambulacral fields, showing various forms of hydrospires. A, Granatocrinus
Derbyensis. B, Granatocrinus Norwoodi. C,*Metablastus lineatus. D, Orophocrinus verus. All sections enlarged
(after Etheridge and Carpenter).

having the hydrospires concealed within the calyx ; but are absent in the
Codasteridae, in which the hydrospires are wholly or in part exposed on the
outer surface.

The hydrospires are bundles of flattened, lamellar tubes, extending under-

1 [According to Wachsmuth these markings are not a mere ornamentation ; but the ridges consti-
tute the sides, and the depressions the floors of a series of small ducts leading from the pinnules to
the median ambulacral groove. In a number of excellently preserved specimens observed by this
distinguished author (Pentremites, Orophocrinus, and Schizoblastus), not only the longitudinal groove,
but also the side grooves throughout the entire field were roofed over by alternately arranged, very
minute plates, extending all the way to the pinnules. The arrangement of the side ducts, their
upward curvature on approaching the main canal, and their relations to the pinnules, leaves scarcely
a doubt that they were closed food-grooves serving to conduct nutriment from the pinnules to the
mouth.

It is questionable whether the term " pinnules " is strictly appropriate as applied to the appendages
of Blastoids, for while the latter evidently performed the function of arms, it is by no means certain
that they discharged the ova, which is the special office of pinnules in Crinoids. The statement that
the appendages are frequently biserial does not agree with the observations of Wachsmuth. All the
specimens examined by this writer are uniserial, but the ossicles are sometimes sharply wedge-shaped,
and interlock to a slight extent from opposite sides, thus simulating a biserial arrangement. — TRANS.]

CLASS HI

BLASTOIDEA 193

ncath the lancet- and side-plates, in a direction parallel with the boundaries of
tin- anilMilaeral tit-Ms. They begin at the lower end of the ambulacra, and
terminate in the hydrospire canals, of which the spiracles form the external
apertures. When the spiracles are confluent, the canals of adjacent groups of
hvdrtispin-s «inter t he sanu- opening. The hydrospires are suspended in the
majority of forms along the walls of the body-cavity (Pentremites), (Fig. 317),
l.cinur attached either to the outer margins of the under lancet-plate or to a
separate piece known as t he ln/<lrospire plate (Granatocrinus, Mesoblastus, and ('/•//•/>/»
M/X///S). l'< nfirmitt's has from four to nine hydrospires in each group ; Granato-
ri'imix two, or exceptionally one; Troostocrinus and Mesollastus generally three,
and <)r»i<1«i,Tinit* from five to seven (Fig. 318, A to D). In Phaenoschisma and
I'lH/imfi-r (Fig. 323) the tubes open externally by slits piercing the radials and
deltoids and running parallel with the ambulacra.

The functions of the hydrospires can only be surmised, but they are
supposed to have served for respiration ; they correspond doubtless to the
pet 'tinated rhombs and calycine pores of the Cystideans and to the respiratory
pores of Crinoids. It is probable that water was admitted to the hydrospire
sacs through the marginal pores, and was discharged through the spiracles.
Roemer and Forbes have suggested that the hydrospires may also have per-
formed reproductive functions. Ludwig has called attention to the resemblance
between the genital bursae of Ophiuroids and the slit-like spiracles in Oropho-
rriiiiix: his theory is that the hydrospires served both for purposes of respiration
and for the discharge of genital products, a view which was also shared by
Carpenter.

The stem in Blastoids is preserved only in exceedingly rare instances. It
is round, provided with a small axial canal, and composed of short joints,
which apparently multiplied in a similar manner as in the Crinoids. In Oro-
phocrinus and Pentremites it has been traced for a length of 15 cm. without
reaching the end ; and in the latter form it has occasionally been found with
a few, comparatively heavy, radicular cirri.

It has frequently been claimed, owing to the superficial resemblance of their
ambulacral areas, that the Blastoids and Echinoids are mutually related ; but
such presumptions are founded upon a total misconception of the value of
external characters. The construction of the calyx, the presence of pinnules,
and the stemmed condition, are features which identify them unmistakably as
Pelmatozoa ; and their nearest relatives under this group are the Cystideans.
The parallelism between the ambulacral fields of the one class and the recumbent
arms, apparently soldered on to the calyx of the other, is self-evident. The
hydrospires of Blastoids correspond to the pore-rhombs of Cystideans, as has
already been remarked ; and the position of the mouth and anus is the same
in both types. The Blastoids constitute a peculiar, but, on the whole, a very
well-defined group, which is now regarded as of equal rank with the Crinoids
and Cystids.

Blastoids have not been recognised as such, up to the present time, in
strata lower than the Silurian ; but it is possible that several genera occurring
in the Ordovician of North America and Russia (Blastoidocrinus, AsteroUastus,
etc.), which are now referred to the Cystids, may eventually be transferred to
the Blastoidea. The only known Silurian form is Troostocrinus, which occurs
sparsely in the Niagara Group of North America. Several genera are repre-
sented in the Devonian, being distributed in both Europe and America, but
VOL. I

194

ECHINODERMATA— PELMATOZOA

SUB-KINGDOM III

the climax of Blastoid development takes place in the Sub-Carboniferous of
North America. Some of the beds of the Kaskaskia Group are fairly charged
with their remains, which as a rule are excellently preserved ; but above this
horizon no traces of them have as yet been discovered. Nineteen genera,
comprising upwards of 120 species, are recognised by Etheridge and Carpenter
in their admirable monograph.

Order 1. REGULARES. Etheridge and Carpenter.

Pedunculate Blastoids with a symmetrical base, in which the radials and ambulacra
are all equal and similar.

Family 1. Pentremitidae. d'Orbigny.

usually convex, and often much elongated. Spiracles five, but sometimes more
or less completely divided by a median septum, and bounded proximally by the upper-
most side-plates. Lancet-plate either entirely visible or partially covered by side-plates
which extend to the margins of the ambulacra. Hydrospires concentrated at the lowest
part of the radial sinus. Devonian and Sub-Carboniferous.

Pentremites, Say. Calyx usually ovate or pyriform, with elongate, sub-
truncate base. Ambulacra broad, sub-petaloid. Lancet-plate wholly exposed,

and resting below on an under lancet-plate.
Side-plates and outer side-plates' numerous,
the former abutting against the edges of the
lancet-plates. Hydrospires three to nine ;
spiracles single, or occasionally double ; the
two of the posterior side confluent with the
anus, and forming with it a single large
orifice. Summit covered by numerous spines,
placed closely against one another so as to
form a pyramid, which completely covers
the summit and the greater portion of the
spiracles. Excessively abundant in the Sub-
Carboniferous of North America (St. Louis
and Kaskaskia Groups), but not identified
in Europe. P. Godoni, Defrance, and P. pyri-
formis, Say, are the most familiar species.

Pentremitidea, d'Orb. Calyx clavate-
pyramidal, with elongate, usually conical
base, and truncate or convex upper face.
Ambulacra narrow, short; lancet-plate more
or less completely concealed by side-plates.
Deltoids very small, generally confined to the upper face of the calyx, and
seldom visible in a side-view. Spiracles and hydrospires as in the preceding.
Lower and Middle Devonian; Eifel, Ardennes, Spain, Great Britain, and
North America. P. Pailletti, de Vern. ; P. Eifelianus, Eoemer ; P. clavatus,
Schultze.

Mesoblastus, E. and C. Calyx oval to globose, with concave to protuberant
base. Radials long, deltoids small, short, unequally rhombic. Ambulacra

FIG. 319.

Pentremites
Co'/niii, Defr.
Sub-Carbon-
iferous ; 111.
(Nat. size.)

FIG. 320.

Pentremites sulcatus,
Roein. Sub--Garbonifer-
ous ; 111. A, Summit as-
pect. B, Base.

OKM:I; I

BLASTOIDKA—

195

very narrow. extending to the base. Spim- !••-. M -i rule, distinctly double,
but sometimes incompletely divided. Lancet-plate perfectly, or for the most

part, concealed by >ide plates. Carboniferous; Belgium, England, North
America. .]/. .-/•»//»/ /*////*, Koeiner.

Family ~2. Troostoblastidae. Etheridge and Carpenter.

Ambulacra narrow, linear, deeply impressed, descending outward from the summit.
confined to the narrow upper end, invisible externally, except the posterior one
in '/'/•'" -.-/",•/ //n/.s-. Ln ncet- plate entirely concealed by side-plates. A

f, rqprtttntod !»/ lineal slits at the sides of the deltoid
', a nil IK it l><> a mled by side-plates. Silurian to Sub-Carbon-
iferous (Warsaw Group).

Troostocrww, Shum. (Fig. 321). Calyx narrow, elongate,
somewhat fusiform, with contracted, subtruncate, or slightly
convex upper face. Ambulacra short. The four anterior
deltoids overlapped by the radia limbs; the posterior one
much larger than the rest, and appearing externally. Posterior
spiracles confluent with the anus. Silurian (Niagara Group) ;
North America.

Metablaslus, E. and C. Like the preceding, but all the
deltoids equal, and the two posterior spiracles not confluent
with the anus. Spiracle slits ten in number; hydrospires
four lo each side of an ambulacrum. Silurian to Sub-Car- ,

. ... 1 roostocnnus Rein-

boniferous. iw ,-,/«, Troost sp.

Tricoelocrinus, M. and \V. Calyx pyramidal, broadest below faffe™" ; RoeTner"'.
and narrowing upwards; when seen from above or below, da?al'(nafrom8izex
strongly pentagonal in outline, owing to the projecting and Lf^,1'1 asl"(t
carinated character of the radials. Deltoids small ; ambulacra

long, and extremely narrow. Spiracles ten, dis-
tinct ; anus large. Hydrospires small, enclosed
within the substance of the forked plates. Sub-
Carboniferous.

Family :i.

Nucleoblastidae.
Carpenter.

Etheridge and

Fie.

Elaeacrinus * Verneuili, Troost sp.
Lower Devonian ; Columbus, O. (after
II'M-mcr). .1. SHIe-VteW of calyx.
/-', H;is,-. C, Ventral surface. I), Same,
enlarged.

Calyx usually globular or ovoidal, with flattt m><l
or concave base, and linear ambulacra extending the
//7/r<V length of the calyx. Spiracles distinctly double,
and chiefly formed by the apposition of notches in the
1 <i if' ' -plate and deltoids. Devonian and Sub-
Carboniferous.

Etheridge and

Sub-Family A. ELAEACRINIDAE.
Carpenter.

Posterior deltoid divided into two parts by an anal
plate. Anus distinct from the posterior spiracles.

Elaeacrinus, Roemer (Nucleocrinus, Conrad), (Fig. 322). Basals small,
inconspicuous, sometimes hidden within the columnar cavity. Radials small,

196 ECHINODERMATA — PELMATOZOA SUB-KINGDOM in

with very short limbs. Deltoids greatly enlarged and elongated, forming
over two-thirds of the entire calyx ; the posterior one wider than the others,
and divided by a large anal plate. Lancet-plate exceedingly long and narrow,
partly exposed. Side-plates numerous ; hydrospires two to each side of the
ambulacra. Summit covered by comparatively large orals, asymmetrically
arranged and forming a flattened disk which completely closes the peristome.
Devonian ; North America.

Sub-Family B. SCHIZOBLASTIDAE. Etheridge and Carpenter.

The posterior deltoid not divided by an anal plate. Posterior spiracles may be
fused with the anus.

Schizoblastus, E. and C. Calyx resembling that of Granatocrinus in form.
Basals almost always confined to the lower face of the calyx ; deltoids of
variable size, but always visible in a side view. Hydrospires one to four tp
each ambulacrum. Spiracles small, slit-like, placed between the lancet-plates
and deltoid ridges ; the posterior pair sometimes confluent with the anus.
Sub-Carboniferous ; Ireland and North America.

Cryptoblastus, E. and C. Calyx sub-globose, with a flattened or slightly
hollowed base. Basals and deltoids small. Lancet-plate separated from the
radials by a hydrospire-plate, which does not extend above the radio-deltoid
suture ; but above this line the lancet-plate meets the deltoids without leaving
any hydrospire-pores. Spiracles round, distinctly double at four of the sides,
but those of the posterior side confluent with each other and with the anus.
Summit covered by numerous, irregularly arranged small pieces. Sub-
Carboniferous ; North America.

Acentrotremites, E. and C. Calyx elliptical, with broad pentagonal lower
face. Radials large, taking up three-fourths of the height of the calyx.
Deltoids unequally rhombic, each notched by two spiracles at the ends of the
radio -deltoid suture. Anal opening situated close to the summit in the
posterior deltoid. Ambulacral edges of the deltoids without hydrospire pores.
Sub-Carboniferous ; Great Britain.

Family 4. Granatoblastidae. Etheridge and Carpenter.

Calyx globular or ovoidal, with flattened or concave base, and long linear ambu-
lacra. Spiracles five, piercing the deltoids, or ten, grooving their lateral edges.
Sub-Carboniferous.

Granatocrinus, Troost (Figs. 316, 318, A, B). Calyx ovate to globose.
Lower face from slightly concave to deeply funnel-shaped ; interradial areas
more or less depressed. Basals small, generally concealed in the central
columnar cavity. Radials very variable in size, often long, and invariably
turned in below to assist in forming the base. Deltoids also variable ; usually
unequally rhombic, but sometimes triangular; the anal deltoid frequently
differing from the others. Ambulacra nearly parallel-sided, always impressed
within the sinuses at their proximal ends. Lancet-plates narrow, not filling
the sinuses, and mere or less exposed throughout two-thirds of the ambulacra.
Side-plates transversely elongated*; outer side-plates generally well developed.
Hydrospires pendent, usually but two or three folds on each side of an am-
bulacrum ; the inner one forming a well-defined hydrospire-plate. Spiracles

BLASTOIDEA— REGULARES

197

five, piercing the apices of the deltoids. Posterior spiracle larger, including
the anus. Summit closed by minute pieces which rarely exhibit any definite
arrangement. Sub-Carboniferous ; England and North America.

Heteroblastus, E. and C. Kesembling the preceding in form and proportion
of its component parts. The proximal ends of the deltoids produced in short
spine-like processes, sit tin- bas«- of which minute lateral openings, one to each
deltoid, are visible. These openings lead into gutter-like channels excavated
in the substance of the plates for the reception of the proximal ends of the
two hydrospire - canals. Radial sinuses wide, their edges sloping gently
downwards to the slightly petaloid ambulacra. Carboniferous Limestone ;
England.

Family 5. Codasteridae. Etheridge and Carpenter.

Base usually well developed, and sometimes very long. Ambulacra without
ni'injinal pores. JIt/'/r»x/>ire-slits either whollij exposed, piercing the calyx plates
tifiniff the sides of the radial sinuses, or restricted portions of them remain open as
spiracles, while the remaining parts are concealed by the ambulacra. Devonian and
Lower Sub-Carboniferous.

Codaster, M'Coy (Codonaster, Roemer), (Fig. 323). Calyx inverted, conical,
or pyramidal. Upper face broad, truncate, or gently convex ; section, as a
rule, distinctly pentagonal. Basals forming a conical or triangular cup,

Codastn- unit,'*, M'Coy. Carboniferous Lime-
st<m.-; Derbyshire. A, Side-view of calyx.
B, Base. C, Ventral aspect, enlarged (after

I-' 1 1 • '-^9d

Orophocrinus stelliformis, O. and 8. sp. A, Calyx
and base of the natural size. B, Ventral surface en-
larged (after Meek and Worthen).

usually deep. Radials large, their limbs bent inward horizontally, to assist
in forming the truncated upper face of the calyx, and never deeply excavated
by the sinuses. Deltoids wholly confined to the upper face, as are also the
ambulacra. The latter are petaloid, or narrow and linear ; lancet-plate, as a
rule, deeply excavated for the side -plates. Spiracles absent, hydrospires
pendent, arranged in eight groups, two in each of the four regular interrays,
but wanting in the anal one. The tubes open externally by a variable number
of elongated slits, which are separated by intervening ridges ; one or more of
them may be partially concealed by the overlapping side-plates. Anus large,
ovate, or rhombic, and piercing the posterior deltoid. Ornament consisting
of fine lines arranged parallel to the margins of the plates. Silurian to Sub-
Carboniferous ; Europe and North America.

Phaenoschisma, E. and C. Calyx resembling that of Codaster in general
form, but with ten groups of hydrospires instead of eight. Radials bear each
three more or less distinct folds diverging from the lip ; sinuses wide and

198 ECHINODEEMATA— PELMATOZOA SUB-KINGDOM in

deep, generally with steep sides. Deltoids small, confined to the truncated
upper face of the calyx. Lancet-plates in all but one species (P. caryophyl-
latum) concealed by the side-plates ; outer side-plates very small. Spiracles
rarely present. Hydrospires pendent, and opening externally by a series of
elongate slits with intervening ridges, distributed in sub-parallel order on the
sloping sides of all the radial sinuses. The slits are only partially covered
by the ambulacral plates, and are sometimes visible for their entire length.
Lower Devonian ; Spain. Sub-Carboniferous ; Europe and North America.

Cryptoschisma, E. and C. Calyx elongated, with a broad, flat, truncated
upper face. Radial sinuses wide and open, their sloping sides pierced by
hydrospire-slits, which are completely concealed by broad, petaloid ambulacra.
Spiracles small, single, or more rarely double ; in the latter case the posterior
pair are confluent with the anus. Represented by the solitary species C.
Schultzi, d'Archiac et de Vern. Lower Devonian ; Spain.

Orophocrinus, v. Seebach (Codonites, M. and W.) Calyx balloon-shaped to.
truncate ob-pyramidal, with more or less concave upper face. Section dis-
tinctly pentagonal or stellate. Ambulacra narrow, linear to sub-petaloid.
Deltoids generally visible in side-view, the posterior one wider than the
others. Spiracles ten, varying from wide clefts along the sides of the ambu-
lacra to narrow slits at their upper ends ; the posterior pair separate from
the anus. Hydrospire-slits almost completely concealed, being concentrated
at the bottom of the radial sinuses. Stem round, composed of short, nearly
equal joints. Pinnules extending to nearly twice the height of the calyx, of
uniform thickness throughout, and composed of sharply cuneate pieces inter-
locking from opposite sides ; ventral furrow wide, and covered by small pieces.
Sub-Carboniferous ; Great Britain, Belgium, and North America.

Order 2. IRREGULARES. Btheridge and Carpenter.

Non-pedunculate Blastoids in which one ambulacrum and the
corresponding radial are different in form and size from the
others.

Family 1. Astro or inidae. T. and T. Austin.

This family embraces the three rare genera — Eleuthero-
crinus, Shum. and Yandell (Fig. 325), occurring in the
(iumani Devonian of North America ; Astrocrinus, Austin ; and
Lower Devonian ; Ky! Pentephyllum, Haughton. The two latter forms are found
ancuT)' 2/1' in the Carboniferous Limestone of England and Scotland.1

1 [The substance of the editorial notes in brackets occurring throughout the Crinoid and Blastoid
chapters has all been very kindly communicated by Mr. Charles Wachsmuth. Much of this matter
embodies the results of original and as yet unpublished observations. Special acknowledgments are
therefore due to Mr. Wachsmuth, without whose generous assistance the above-named chapters of
the present edition would have been imperfect in many respects. — TRANS.]

ASTEROZOA 199

SUB-BRANCH II. Asterozoa. Leuckart.1

iilessEchiiwIi-rni* > <• I th depressed , /«•///<///"/////, <>,• star-shaped body, consisting of
,t central '//.</.• "//«/.///>' <>r mmr /V///.S (,>,- " iinns"). Mouth inferior and central in
jfixffi'in. . liiibnlnrnil f,i/,,'fnf rrdriHnl to the under surface of the rays. Internal
th'lt'tnn, pieces of the «///W//ov> nrf/mlafnl together like vertebrae, or apposed lib1 ///>•
ruff* rs of a pent-house. Integument coriaceous, strengthened by small, irregular,
loosely tut H<;/ mlcareous plates, some of which bear spines, bristles, protuberances, or
jHi/'/ilae ; the whole constituting a covering of the most varied kind.

The Asterozoa comprise the two classes of Asteroidea, or Star-fishes ; and
<>/>/// ii roidea, or Brittle-stars and Sand-stars. In both types the body consists
of a central disk containing the principal viscera, and giving off five or more
radiating processes or arms. The radiating ambulacral vessels are protected
l»y ;in internal skeleton consisting of a double row of calcareous bodies (am-
Imhn-ral ossicles), the components of each pair being separated and movable to
a slight extent in the Asteroidea, but are welded together so as to form a
series of disks in the Ophiuroidea. The ambulacral grooves are open in the
Asteroidea ; but in the Ophiuroidea they are covered by dermal plates, and
the tube feet project at the sides of the arms. The integumentary skeleton
appears leathery on the dorsal surface, but is generally strengthened by
innumerable small calcareous bodies, on some of which are placed movable
spines or bristles.

Fossil Asterozoans are found as far back as the Cambrian era, and are
represented continuously down to the present time. They are of rather
uncommon occurrence, and are found, as a rule, in calcareous or arenaceous
strata which have been deposited in shallow water. The Asterozoans are the
most homogeneous and most persistent type of all the Echinodermata. Both
the Asteroidea and Ophiuroidea are represented in the Ordovician and Silurian
by well-differentiated forms which do not differ materially from those now
living. The only noticeable difference is that many of the Palaeozoic
Asterozoans exhibit an alternate arrangement of the ambulacral ossicles,
these being developed in all recent species in a double row, with the ends
directly apposed. The more or less disjunct condition of the vertebral
ossicles in Palaeozoic Ophiuroids must be regarded as an embryonic character.

1 Literatim- :

M;HI,'r, ,/., anil Troschel, F. //., System der Asteriden. Braunschweig, 1842.
7- '"/•/»«, E., Monograph of the Echinodermata of the British Tertiaries (Palaeont. Soc.), 1852.
Billings, E., Figures and Descriptions of Canadian Organic Remains (Geol. Survey, Canada,

Decade III.), 1858.
MVi/////. 7*., .Monograph on the British Fossil Echinodermata of the Oolitic Formations, vol. II.,

Asteroidea and Ophiuroidea (Palaeont. Soc.), 1863-80.
Hull, J., Twentieth Report on the New York State Cabinet, 1868.
V"«.sY,v//', F. A., Petrefactenkunde Deutschlands, Band. IV., 1874-76.
/./'(//'•/</, //., Morphologische Studien an Echinodermen. Leipzic, 1877-79.
.Y' •"///"//>•, .I/., .Morphologische Studien iiber fossile Echinodermen (Sitzungsber. Wien. Akad.

I. XXX IV.), 1881.
Carpenter, /'. 11.. Minute Anatomy of the Brachiate Echinodermata (Quart. Journ. Microscop. Soc.,

XXL), 1881.
Sttoix, /!., Beitrage zur Kenntniss palaeozoischer Seesterne (Palaeontographica, XXXII. and XXXVI. ),

1886, 1890.
Sfdrtz, B., Ueber versteiuerte und lebende Seesterne (Verhandl. d. naturhist. Vereins Rheinlande,

Westphalen, etc., 5th Folge, Bd. X.), 1892.

200 ECHINODEBMATA— ASTEROZOA SUB-BRANCH n

The ventral position of the madreporite in Palaeozoic Star-fishes and the
absence of mouth shields in Palaeozoic Ophiuroids point to an intimate
relationship between the two groups ; and this inference is still further con-
firmed by our knowledge of several recent and fossil intermediate forms
(Astrophiura, Protaster, Brisinga, etc.)

If one places a Star-fish or Brittle-star with the mouth uppermost, it will
be seen that the actinal side corresponds with the tegmen, and the central
disk with the base of a Pelmatozoan. When oriented in this manner, the
position of the principal organs (ambulacral, circulatory, and nervous systems)
is the same in both groups. The homology between the arms of an Astero-
zoan and those of a Crinoid or Cystid, or the ambulacral fields of a Blastoid,
can also hardly be doubted. But efforts to interpret a homology between
plates of the dermal skeleton as developed in either group have been only
partially successful ; the reason being that these structures became variously
modified and specialised throughout the different classes at an extremely
early period.

A comparison of the ontogenetic stages passed through by the Pelmatozoa
and Asterozoa reveals nothing definite in regard to their close relationship ; but
the identity in position of the principal viscera argues strongly in favour of their
common origin. The Asterozoans are most nearly comparable with certain of
the Cystideans (Agelacrinus and the Callocystidae). But that they are the
direct descendants of the Cystoidea appears very improbable, for both geological
and morphological reasons. The fact is, that both types appear simultaneously
and in a high state of development, each being totally distinct from the
other, as far back as the Cambrian.

Class 1. OPHIUROIDEA. Gray. Brittle-stars. 1

Asterozoans having a more or less sharply defined central disk containing a
simple digestive cavity which does not radiate into the slender rounded arms, and
has no anal opening. Reproductive organs confined to the disk. Arms with an
axis composed of jointed calcareous disks, encased with plates or covered with a
leathery skin, and destitute of open ambulacral grooves. Madreporite constantly on
the actinal (oral) side of the disk.

Ophiuroids are distinguished from the typical Star-fishes by their cylin-
drical flexible arms, wm§k are sharply separated from the central disl^ and
do not contain diverticula of the alimentary canal nor of the sexual organs.

1 Literature :
Liitken, C. F., Additamenta ad historiam Ophiuridarum (Kongl. dan. Vidensk. Selskabs Skrifter, V.

and VIII.), 1858-69.
Lyman, T., Ophiuridae and Astrophytidae (Illustr. Cat. Museum Comp. Zoology, Cambridge. Nos.

I.-IIL), 1865.
Lyman, T., Ophiuridae and Astrophytidae. new and old (Bull. Museum Comp. Zoology, Cambridge,

III.), 1874.
Ludvrig, H., Beitrage zur Anatomie der Ophiuren (Zeitschr. fiir wissensch. Zool. XXXI.-XXXIV.),

1878-80.

Ludwig, H., Morphologische Studien an Echinodermen. Leipzic, 1877-79.
Lynian, T., Report on thr Ophiuroidea (Challenger Expedition, Zoology, vol. V.), 1882.
Picard, K., Ueber Ophiuren aus dem oberen Muschelkalk (Zeitschr. d. deutsch. geol. Gesellsch.

XXXVIII.), 1886.
Boehm, G., Beitrag zur Kenntniss fossiler Ophiuren (Berichte d. naturf. Gesellsch., Freiburg, V.),

1889.

CLASS I

OPHIUROIDEA

201

The arms serve as -locomotive organs, and are either elegantly plated
(Ophiureae), or protected by a coriaceous skin, in which minute granules and
scales are embi-ddrd ( EwyaUae). When plated, the covering consists typically
of four rows of calcareous plates, known as the upper, lower, and side arm-
plates (Scutella dorxdia, nnfmlia, and lateralia), (Fig. 326, A). The lateral
or ,n /ambulacral plates usually carry rows of mobile spines.

The greater part of the interior of the arms is occupied by a linear series ot
jointed, vertebrae-like sections called the vertebral ossicles or arm-bones, each of
which is made up of two ambulacral pieces soldered side by side (Fig. 326,
B, C). The halves of the first two vertebral disks are swung laterally into
the iriterbrachial space, being fused together to form the mouth angle. The
remainder of the arm-bones are movably articulated with one another by
means of bosses which project from the centres of both surfaces, the inter-
spaces being filled with muscles. The entire series is incised inferiorly along
the median line for the reception of the radiating water-tube, beneath which

V Fi.:. 3215.

A, Vertical section of an Ophiuran ami. w, Vertebral ossicle ; a, Ambulacral vessel, with side-branches lead-
ing into the tube feet ; b, Blood-vessel ; n, Nerve-cord ; i; Ventral or lower arm-plate ; I, Side-plates ; d, Dorsal
plate B, Vertebral ossicle, seen from the inward side, with BOrroondtng arm -plates. C, Row of vertebral
ossicles viewed from the side, and slightly .-nhn-.-d ; /. Apertures where the branches of the ambulacral vessel
enter and emerge from the arm-bones ; //, Depressions for the insertion of intravertebral muscles. D, Mouth-
frame of an Ophiuran, with the proximal vertebral ossicles. The heavy lilies bordering the arms represent the
bursal fissures ; the dark pentagon in the centre marks the course of the nerve-ring.

runs the radiating blood-vessel and nerve cord, the whole being closed in by
the integument. The radiating ambulacral vessel gives off a pair of lateral
branches in each arm ossicle which pierce the bone itself, and supply the
tentacle-like tube feet with water. The tube feet are without either ampullae
or terminal suckers, and the orifice of the plates through which they protrude
is often protected by one or more minute tentacle scales (papillae ambulacrales),
which serve to cover the tentacles when they are drawn in.

On the under side of the disk is seen the central, pentagonal aperture of
the mouth (Fig. 331), which leads into a large sac-like stomach. The latter
terminates blindly, there being no intestine. The body cavity also contains
the ambulacral, blood, and nerve rings, as well as the generative glands, whose
ducts open into folded pouches or bursae. The bursae are arranged in five
pairs, one to each interbrachial area, and communicate with the exterior by
means of slit-like bursal fissures, which skirt the arm bases inferiorly, and are
bounded by genital or bursal scales. Sometimes the fissures are discontinuous

202

ECHINODERMATA— ASTEROZOA

SUB-BRANCH II

(Ophiura), appearing as two slits one behind the other; and in the fossil
Euryaleae they are often represented by rows of pores.

The integument covering the entire upper surface of the disk and the
interbrachial area on the ventral side is frequently beset with calcareous
plates ; but this scale coat may be covered in turn with a thick skin, or bear
spines or granules. A large central plate is sometimes recognisable on the
dorsal aspect of the disk, together with five pairs of plates, which, from their
position at the points of origin of the arms, are called radial shields (Scutella
radialia, Fig. 328). On the ventral surface of the disk, the inner angle of
each interbrachial space is occupied by a single large plate termed the mouth
shield (Scutum buccale), one of which serves as the madreporic body. But in
the Euryaleae the mouth shields are feebly developed, or may be wanting
altogether ; and in place of them a madreporite is found in one or all of the
interrays. The mouth shields are bounded proximally by a pair of somewhat

FIG. 327.

Portion of central disk of Ophioglypha
viewed from the ventral side, a, Mouth
shield ; b, Side mouth shield ; c, Jaws
covered by papillae ; g, Bursal fissures ;
h, Side arm-plates ; i, Pores for the emis-
sion of the tube feet, surrounded with
tentacle scales ; k, Spines.

FIG. 328.

Portion of central disk of Ophioglypha viewed
from the dorsal side. a, Radial shields ;
b, Upper arm-plates; c, Side-plates.

smaller plates called the side mouth shields (Scutella adoralia). Finally, within
the side mouth shields, and usually pressing against them, are the jaws (Scutella
or alia ; Mundeckstiicke}, which are sometimes covered by the skin or by granu-
lations (Fig. 327). Teeth are constantly present, being attached to the jaw-
plates by small muscles.

The Ophiuroidea are divided into two orders : Euryaleae and Ophiureae, both
of which have fossil representatives dating as far back as the early Palaeozoic
era. For a precise systematic determination it is necessary to know the
character of the bursal fissures' and the mouth frame ; but such evidence is
not always obtainable in the case of fossil specimens, owing to imperfect con-
ditions of preservation.

Order 1. BUR YALE AE. Miiller and Troschel.

Arms dichotomously dividing soon after their origin (exceptionally simple
throughout their entire length), capable of being rolled up inwards, and covered with
a granulated or finely scaled integument. Mouth shields rudimentary or absent.
Genital fissures often represented by rows of pores. A madreporite present in one or
all of the interrays. Silurian to Eecent.

The Palaeozoic species differ from all of the recent Astrophytidae in that
radial shields are not present, and that the arms bear a row of simple marginal
spines on the ventral aspect.

ORDER II

OPHIUROIDEA— OPHIUREAE 203

Woodw. Disk granulated. Each of the arms giving off five
pairs of secondary branches, which ,\ /,

increase in size outwards. One
niadreporite present. Silurian :
England,

'7>".s/</\ Meek and Worth.
(Vntral disk round, small. Arms five,
simple, long, and covered with a tuber-
culous int e^unient, in which fine scales
are embedded. Sub - Carboniferous ;
North America.

? Hcliitiithiixtcr, Roemer. Disk large,
granulated. Arms sixteen, long, broad,
and covered with a granulated integu-
ment. Lower Devonian ; Bundenbach. dorgal coverin of the v,.Iltril (lisk is r-(MlloVed ex-

.' Kiin/tllc, Lam. It is possible that posing the mouth franu-. /., M.iutli tVami- .-ular-i-il,
, , • j ••! i i viewed from above ; c, vertebral ossicle, enlar^1'1'-

the rough impressions described by

Quenstedt as Euryale liasica, from the Angulatus Bed of Niirtingen (Lias a),

also belong here.

Order 2. OPHIURBAB. Miiller and Troschel.

Arms invariably simple, incapable of being rolled up towards the mouth, and, as
" /'///', cased with four series of integumentary plates. Silurian to Recent.

Mouth shields are well developed in recent forms, one of them serving as a
madreporite ; but they are absent in all fossil species.

Sub-Order 1. OPHIO-ENCRINASTERIAE. Stiirtz.

Arms without ventral shields, the lateral elements of the vertebral ossicles dis-
junct, and alternately arranged. Mouth shields absent. Disk covered with skin or
fine scales, sometimes spinous. Silurian and Devonian.

To this sub-order belong the following genera : — Protaster, Forbes, from the
Silurian of England and America. Taeniaster, Billings ; Silurian. Eugaster,
Hall ; Devonian. Palaeophiura and BundenbacJiia, Stiirtz ; Lower Devonian.

Sub-Order 2. PROTOPHIUREAE. Sturtz.

» Arms without dorsal, sometimes without ventral shields. Elements of the verte-
bral ossicles placed opposite one another, and more or less anchylosed. Disk without
either radial shields, mouth shields, or genital scales. Silurian and Devonian.

The % sub-order is divided by Sturtz into three groups, comprising the
following species : —

(a) Ophiurina Lymani, Sturtz. Lower Devonian ; Bundenbach.

(b) Protaster Miltoni, Salter. Silurian ; England. Furcaster palaeozoicus
and Ophiurina Zitteli, Sturtz. Lower Devonian ; Bundenbach.

(c) Ophiura primigenia, O.Decheni, and O.Rhenana, Sturtz. Lower Devonian;
Bundenbach.

204

ECHINODERMATA— ASTEBOZOA

Sub-Order 3. EUOPHIUREAE.

SUB-BRANCH II

Arms with dorsal, lateral, and ventral shields. Mouth shields well developed,
one of them serving as a madreporite. Devonian to Eecent.

FIG.

Aspidura loricata, Goldf. sp. Muschelkalk ; Waschbach, Wurtemberg. A, Group of individuals of the
natural size (after Quenstedt). B, Ventral aspect enlarged (after Pohlig).

The Ophiuroids of the Mesozoic
era are closely related to recent forms,
and are all assignable to families now
in existence. Most of them have but
two bursal fissures in each interradium ;
but the genus Ophiura, Lam. (Ophio-
derma, M. and T.), has four in each
interray, and is represented as early
as the Trias (0. Hauchecorni, Eck :
Muschelkalk. 0. Egertoni, Brod. sp. ;
Lias).
FIG. 33i. The genera Aspidura (Fig. 330)

Ophiocten Kelheimense, Bohm. Lithographic Slates ; arifl /Jrriirn Acra<5«5i7 arp orrasionallv
Kelheim, Bavaria. A, Ventral aspect of disk, enlarged. anQ ^^^^ AgaSSlZ, are

B, Dorsal surface of one of the arms. (Both figures abundant in the German Muschelkalk,

enlarged ; original in Munich Museum.) , T . . -. , . -,

and certain Liassic Ophmrans also

FIG. 332.

Geocoma carinata, Goldf. Lithographic Slates ; Zandt, near Solenhofen, Bavaria. A, Individual of the
natural size. B, Dorsal aspect of disk, showing granulations and central depression. C, Ventral surface of one
of the arms. (Figs. B and C enlarged.)

lived in herds. In the Lower, Middle, and Upper Jura are found forerunners

CLASS ii ASTEROIDEA 205

of the recent genera Ophiolepis, M. and T. ; Ophiocten, Liitk. (Fig. 331) ; Ophio-
f/l I//I/KI, ,'iinl (>i>lnoiinn<iiiiit, Lyman. Some of the forms described under the head
of Geocoma, d'Orb. (such as G. socialis, Heller, from the Callovien of La Voulte ;
or G. Libanotica, Konig, from the Cretaceous of Hakel, Lebanon), are incap-
able of precise determination ; others (such as G. carinata, Goldf., Fig. 332)
are closely related to the recent Amphiura. •

Ophiurella elegans, Agassiz, from the Lithographic Slates of Solenhofen, is
referred by Liitken to Ophiocoma, Agassiz. Other Jurassic and [Cretaceous
forms which have been described under various generic names are assigned
by the same author to Ophioglypha, Lyman. Fossil Ophiuroids which do not
admit of critical determination are usually grouped together under the general
term of Ophiurites.

Class 2. ASTEROIDEA. Star-fishes.1

Asterozoans whose simple and more or less flattened arms are prolongations of
the central disk, and contain the hepatic appendages of the alimentary canal, as well
as the generative organs. Ambulacral feet disposed in rows along deep open
grooves on the under or actinal surface of the arms.

Star-fishes have typically five arms (but in some cases as many as eight,
ten, twelve, twenty, or more), which are prolongations of the central disk,
and are not sharply marked off from the same. The integumentary skeleton
consists of plates which are either contiguous with one another along their
edges, or are united in a reticulate fashion, and covered with a leathery skin.
The calcareous plates often bear movable spines or bristles, or they may be
tuberculated or granulated. The abactinal surface usually exhibits a central
or subcentral anus, and also a madreporite, which is situated in one (rarely
two or more) of the interradii. The madreporite is covered with labyrinthic
furrows, and is perforated for the admission of water into the so-called stone
canal, whence it is conveyed into the water-vascular ring surrounding the
mouth. The fine pores and protrusive coecal processes (papulae), which in the
Phanerozonia are restricted to the dorsal surface, but in the Cryptozonia are
distributed over the whole body, serve as respiratory organs, the body fluids
being brought into close contact with the oxygenated water.

The mouth occupies the centre of the dorsal surface, and is pentagonal in
contour, owing to the projection of five pairs of interradially disposed oral

1 Literature:
Forbes, K, British Fossil Asteridae (Mem. Geol. Survey, vol. II., Part II., and Decade III.), 1848

and 1850.

Salter, J. IV., New Palaeozoic Star-Fishes (Ann. and Mag. Nat. Hist. XX.), 1857.
Gray, J. E., Synopsis of the Species of Star-Fish in the British Museum, 1866.
Simonowitsch, S., Ueber einige Asteroiden der rheinischen Grauwacke (Sitzuugsber. Wieu. Akad.

LXIV.), 1871.

Sars, G. 0., Researches on the Structure, etc., of the genus Brisinga. Christiana, 1875.
Perrier, E., Revision de la Collection des Stellerides du Museum d'Hist. Nat. de Paris (Arch, de

Zool. Experim. IV., V.), 1875-76.

Agassiz, A., North American Star-Fishes (Memoirs Museum Comp. Zoology, Cambridge, V.), 1877.
Viguier, C., Anatomic comparee du squelette des Stellerides (Arch, de Zool. Experim. VII.), 1878.
Sladen, W. P., Report on the Asteroidea (Scient. Results, Challenger Expedition, XXX.), 1889.
Sladen, W. P., Monograph on the British Fossil Echinodermata from the Cretaceous Formations,

Vol. II. Asteroidea (Palaeontographical Society), 1890-93.
Fraas, £., Die Asterien des weissen Jura (Palaeontographica, XXXII.), 1886.

206

ECHINODERMATA— ASTEROZOA

SUB-BRANCH II

plates. Each of the arms is traversed on the under or oral side by a broad
and deep furrow, which tapers gradually in passing from the mouth to the
tip of the arm, where it is terminated by a simple grooved plate (Fig. 333)
called the ocular plate. The roof of each ambulacral furrow is formed by two

rows of rafter-like, rather elongate, ambulacral
ossicles, the inner ends of which are held
together by muscles (Figs. 334, 335). Run-
ning along the centre of the groove on its
ventral side are placed in succession the radial
water-tube, blood-vessel, and nerve cord.
tagonaster (?)"' from These are all homologous with the like-
Itoeiteg6." ?/r "f named organs of Ophiuroids.

The form of the ambulacral ossicles
varies in different genera. In all recent forms the ends are directly apposed
against one another in the median line of the ambulacral grooves ; but in
Palaeozoic forms they are arranged in alternate rows, and are inclined towards
one another at a very small angle. Each pair of ambulacral plates is ex-
cavated at the sides, so as to give rise by their apposition to a series of small

FIG. 333.

Ocular plates of
Pentagonct£ter(T) from
the Upper Jura of
Streitberg. 2/1.

FIG. 334.

Detached ambu-
lacral ossicle of Pen-

md-

Astropecten aurantiaciis, Linn. sp. Recent ;
Mediterranean. Enlarged vertical section of
one of the arms, am, Ambulacral ossicles ;
ad, Adambulacral plate ; mv, Infero-marginal
plate ; md, Supero-marginal plate ; i, Super-
ambulacral plate.

Asterias rubens, Linn. Recent ;
German Ocean. Enlarged vertical
section of one of the arms, am, Am-
bulacral ossicles ; ad, Adambulacral
plates ; mv, Infero-marginal plates ;
a, Radiating water-tube ; &, Ampullae ;
p, Tube feet.

apertures, through which the distensible tube feet or pedicels are emitted,
The latter are the downward prolongations of lateral branches given off by
the radial ambulacral vessel ; the upward prolongations of the same form
small sacs called ampullae, by means of which water is forced into the
tube feet.

The lower ends of the ambulacral ossicles rest against a series of
adambulacral plates, and in many forms these are bounded in turn by large
marginal plates (Fig. 335). Intermediate plates are those which are inserted
between the infero-marginal plates and the adambulacral plates. By the
term dorsal plates are understood all calcareous bodies occurring on the dorsal
side of the body.

Perfectly preserved Star-fishes are known only from a few localities,
such as Bundenbach in Rhenish Prussia, the usual mode of occurrence being
in the form of moulds or detached plates. The earliest forms are found in
Cambrian rocks.

SUB-CLASS I

ASTEROIDEA— ENCRINASTERLE

207

Aspidosvi)inpet(il(riiles,$\iii(>n. Lower Devonian ; vicinity
f Niederlahnstein, Nassau. ,4, Ventral aspect, natural size.

Sub-Class 1. ENCRINASTERIAE. Bronn.

Palaeozoic Star-fishes with hit slightly inclined ambulacral ossicles, their ends

meeting alternately in the middle of

the ambulacral grooves. Madreporite

situated on the oral &•!•' <>f the disk.

Cambrian to Carboniferous.

Two principal groups may be

indicated in this sub-class, in one

of which marginal plates are

strongly developed, and in the

other they are either absent or

rudimentary. So little is known,

however, of the complete structure

of the majority of Palaeozoic forms,

that in the case of some genera it

is impossible as yet to determine

positively the group in which they

should be classed.

To the first group belong the

following genera : — Aspidosoma,

Goldf. (Fig. 337). Devonian ; Rhenish Prussia. Palaeaster, Hall (Petraster,

Billings ; Archasterias,
Miiller), (Fig. 338). Ordo-
vician to Carboniferous ;
Europe and North America.
Salteraster, Stiirtz (Palae-
aster,~~!3aTter, p.p.) Ordo-
vician ; England. Palaeo-
stella, Stiirtz. Lower De-
vonian ; Bundenbach.

Palasterina, M'Coy
(Cambrian to Devonian ;.
Europe and North America),
should probably be ranked
in this group as a transitional
form. Ur aster ella, M'Coy
(Stenaster, Billings, p.p.),
(Ordovician ; Canada), is

Palaeaster Eucharis, Hall. Devonian ; Hamilton, New York, also Considered by Stiirtz as
A, Ventral aspect, natural size. If, Dorsal surface of one of the arms. mprnhpr nf r Viic crrnnn
C, Diagrammatic view of ventral surface of the arms (after Hall). lb 81 OUP-

To the second group

belong the genera : Palaeocoma, Bdellacoma, and fihopalocoma, Salter.

Silurian ; England. Loriolaster, Cheiropteraster, and Palasteriscus, Stiirtz.
Lower Devonian ; Bundenbach.

208 ECHINODERMATA— ASTEROZOA SUB-BRANCH n

Sub-Class 2. EUASTERIAE. Bronn.

Pairs of ambulacral ossicles placed opposite each other, inclined upwards like
the rafters of a roof, and united with one another by 'muscles at their inner ends.
Madreporite, except in a few Palaeozoic types, restricted to the dorsal surface.
Silurian to Recent.

This sub-class is divided into two orders, depending upon the character of
the marginal plates. Both groups make their appearance in the Palaeozoic
era, and continue to the present day.

Order 1. PHANBROZONIA. Sladen.

Marginal plates large and highly developed ; the supero-marginal and infero-
marginal plates contingent. Papulae restricted to the dorsal surface. Ambulacral
plates well spaced and usually broad.

Forms apparently congeneric with the recent members of the Archas-
teridae and Astropectinidae are represented in the Devonian. Xenaster,
Simonowitsch, a small, five -armed type from the Lower
Devonian of Rhineland, has adambulacral and intermediate
plates. A large form from the Devonian of Bundenbach,
with five long, depressed arms, rectangular adambulacral
plates, and two rows of marginal plates, is regarded by Sturtz
as 'identical with the recent genus Astropecten, Linck. (Fig.
335). Numerous species referred to the same genus have
been described from the Lias onwards.

The genus Luidia, Forbes, has also been considered to be
v represented by a form from the Lias. Plumaster, Wright,

Pentagonaster(T) ^ . J .

Quenst. from the Lias, is probably a near ally.

hTm Trichasteropsis, Eck. Central disk large. Arms moderately

' iSepere ^on§' tapering, and covered on the ventral side with spines,

infero-marginai Marginal plates rather small, except on the dorsal side at the

plate. C.Plate with • f ^ TIT in n

supposed pedicel- tips of the arms. Muschelkalk.

St). (after Quen" Pentagonaster, Linck (Goniaster, Ag. p.p.) Body depressed
and pentagonal, or with the rays slightly produced. Marginal
plates generally few in number, and decreasing in size on approaching the
extremity of the ray. Abactinal area covered with rounded or polygonal
plates. Cretaceous to Recent.

Metopaster, Sladen (Goniaster, Ag. p.p.), (Fig. 341). Distinguished from
the preceding by the ultimate supero-marginal plates, which are the largest
of the series, and by all the marginal plates having a surrounding border of
setae. Cretaceous.

Mitraster, Sladen (Goniaster, Ag. p.p.) Cycloid in contour, with supero-
marginal plates few in number, and all of nearly the same size. Cretaceous.

Calliderma, Gray. Cretaceous to Recent. Nymphaster, Sladen. Cre-
taceous to Recent. Pycnaster, Sladen. Upper Cretaceous; England. Lep-
taster, de Loriol. Jura.

Pentaceros, Linck (Oreaster, Mull, and Trosch.), (Fig. 341). Fossil forms

ORDER I

ASTEROIDEA— EUASTERIAE

209

occur with large, tuberculous plates on the abactinal area, which are often
armed with powerful spines. Upper Jura to Recent.

Sphaerites, Quenst. Under this title are included detached hexagonal

Fio. 340.

Metopaster Purkinsoni. Forbes sp. Lower Chalk ; Sussex. A, Ventral aspect. B, Viewed from one side
(after Forbes).

plates of variable size and thickness, which are of not uncommon occurrence
in the Jura of Wurtemberg and Switzerland. Some of them bear strong

Fio. 341.

FIG. 342.

Sphaerites scutatus, Goldf.
Upper Jura ; Sontheiin,
Wurtemberg.

Fia. 343.

A, Sphaerites tabulatus,
Goldf. B, S. punctatus,
Goldf. Upper Jura; Streit-
berg, Franconia.

A, Pentaceros iurassicus, Zitt. Upper Jura.; Bemfeld, near Ingol-
sta.lt, Bavaria. I/a- B, P. thoracifer, Gein. Planer ; Plauen, Saxony.
Marginal plate. C, P. primaevus, Zitt. Upper Jura ; Streitberg.

conical spines (Fig. 342), and others are smooth or punctate (Fig. 343).
Their zoological position has not as yet been satisfactorily determined.

VOL. I

210 ECHINODERMATA— ECHINOZOA SUB-BRANCH m

Order 2. CRYPTOZONIA. Sladen.

Marginal plates inconspicuous and more or less rudimentary in the adult.
Supero-marginal plates often separated from the infer o-marginal series by inter-
mediate plates. Papulae distributed over the whole body. Ambulacral plates
crowded and narrow ; tube feet in two or four rows.

Of the Palaeozoic representatives of this order, the genera Lepidaster,
Forbes (Silurian), and JRoemeraster, Stiirtz (Devonian), are related to the
recent genus Linckia, Nardo. The forms described by Stiirtz, Echinasterella,
Medusaster, and Protasteracanthion, from the Devonian of Bundenbach, are
regarded by their author as allied to the Echinasteridae, Asteriidae, and
Brisingidae respectively.

Solaster, Forbes, is represented by a form having numerous arms in the
Great Oolite of England. Tropidaster, Forbes, occurs in the Middle Lias ;
and a solitary species of Echinaster, M. and T. (Ehopia, Gray), has been
described from the Neocomian. A form described by Forbes from the Red
Crag of England was considered by him to be specifically identical with the
existing Asterias rubens, Linn6.1

SUB-BRANCH III. Echinozoa. Leuckart.

Armless and stemless Echinodermata, with globular, cordiform, discoidal, or
worm-like bodies, which are either encased in a plated test or are covered with a
leathery skin, in which minute, detached calcareous bodies are embedded.

The Echinozoa are divided into two classes : Echinoidea or Sea-urchins, and
Holothurioidea or Sea-cucumbers.

Class 1. ECHINOIDEA. Agassiz. Sea-Urchins.2

Echinozoa, with bodies encased in a solid or slightly flexible test, variable in shape
from spherical to flat; composed of numerous, closely placed, more or less geometrical

1 [To Mr. W. Percy Sladen, Vice-President of the Linnean Society, and well known for his
numerous scientific achievements, the author and editor are under special obligations for having
thoroughly revised and enlarged the preceding chapter on the Asterozoa, and also for having
rendered valuable assistance on the Echinozoa. — TEANS.]

2 Agassiz, L., and Desor, E., Description des Echinides fossiles de la Suisse, 1839-40. — Catalogue
Raisonne des Families, Genres, et des Especes de la Classe des Echinides (Ann. des. Sci. Nat.),
1846-47.— d'Orbigny, A., Paleontologie fran£aise (Terrain cretace, vol. VI.), 1853-60.— Cotteau and
Triger, Echinides du departement de la Sarthe, 1855-69. — Desor, E., Synopsis des Echinides fossiles.
Paris, 1858. — Wright, T., Monograph on the British fossil Echinodermata of the Oolitic Formations
(Palaeontograph. Soc.), 1857-80. — Idem, Cretaceous Formations (Palaeont. Soc.), 1864-82. —
Cotteau, G., Paleontologie frai^aise, vols. VII., IX., and X., 1862-79.— Laube, G. C., Echinoder-
men des vicentischen Tertiargebietes (Denkschr. Wien. Akad. xxix.), 1868. — de LorioL P.,
Echinologie helvetique, vols. I. -III. Geneva, 1868-75. — Quenstedt, F. A., Petrefactenkunde
Deutschlands (Bd. III., Echiniden), 1872-75.— Agassiz, A., Revision of the Echini (111. Cat.
Museum Comp. Zool. Cambridge, No. 7), 1872-74. — Reports on the Echini of the Hassler (1874),
Challenger (1881) and Blake (1883) Expeditions.— Loven, S., Etudes sur les Echiuoidees (Svensk.
Veteusk. Akad. Handl., Bd. XL), 1874.— Cotteau, Peron, and Gauthier, Echinides fossiles de
1'Algerie. Paris, 1876-91. — de LorioL P., Monographic paleontologique, etc. (Abhandl. Schweiz.
pal. Gesellsch. III. -VIII.), 1876-81.— Dames, W., Die Echiniden der vicentischen und veronischen
Tertiar-Ablagerungen (Palaeontographica, Bd. XXV.), 1877. — Agassiz, A., Palaeontological and
Embryological Development (Address before Amer. Assoc. Adv. Science), 1880. — Bibliography of
the Echinodermata (Bull. Museum Comp. Zool. Cambridge, vol. X., No. 2), 1882. — Duncan, P. M.,
and Sladen, W. P., Monograph of the fossil Echinoidea of Western Sind (Palaeont. Indica, Ser.

CLASS I

ECHINOIDEA 211

, covered •//•//// *>/'/ .s7/-//<7///vx, <//></ i-nrrifing spines. Mouth on the under or
nrfiim! *///•/'</.-/ : "/'">• *ihnili-'l i-illu-r in fin- ilufun-n ////•/// system or somewhere in tin-
iiiisti'rinr iiifrniiiiliiihii-riiiii. l'lnl<* <>f tin1 ///•'- (/////////("•/•"/ ureas more or less ex-
ti'ntinlii i>< rj«r<itnl fnr lite protrusion <//' fn In- feet.

Tl,,- y;.s/. — The test or covering of Echinoids is composed of numerous
ealeareon> plates, tinnly united by their edges, so as to form a more or less
n'ui'l ease or box, and disposed in eertain regions or systems. In a few
instances, however, the plates overlap one another in an imbricating manner,
so as to impart a certain decree of flexibility to the test. The main element
of the test i> « ailed the corona, and the system of plates at the summit is
known as the »/n/-.s-n.»v////v// or ii/iirnl X//N/V//,.

The test is pierced by two large openings, which are surrounded by
membranes studded with small calcareous particles. One of these is the
ni''iifh, which is always placed on the under or actinal surface of the body,
may be either central or eccentric in position, and is surrounded by a cori-
aceous peristomial membrane. The other aperture is the anus, surrounded by
a periproctal membrane. In some orders it is placed opposite the mouth in
the centre of the apical system, in which case the test is said to be regular or
endocydic. But in other orders it is situated beyond the apical system at a
variable distance in the median line of the posterior interambulacrum, either
dorsally or actinally ; the test is then said to be irregular or exocyclic.

The mouth opens into an oesophagus, which conducts into a capacious
stomach, and thence into a convoluted intestine. The digestive tract winds
round the interior of the test, being attached to the inner surface of the
latter by muscles, and terminates in the anus. Surrounding the oesophagus
is a circular vessel filled with water, which is admitted by the so-called
stone canal, opening externally in a madreporite. This is a porous or sieve-like
structure, consisting of a variable number of canals, and though commonly
restricted to one of the plates of the apical system, it may extend backwards
and perf orate a large part of the system.

The circular vessel gives off five branches, known as the radiating canals,
which pass along the ambulacral areas on the interior of the test, and connected
with it in the interambulacral areas are five distensible membraneous reservoirs,
termed the Polian vesicles. The radiating canals give off numerous lateral
branches or tube feet (tentacles, pedicels) which are capable of protrusion through
pores of the ambulacral plates. Emission is effected by means of secondary
vesicles or ampullae which by contraction force their contained fluid into the
tube feet and distend them. The ampullae, as a rule, communicate with the
tube feet by two canals perforating the plates separately, a single tentacle
being placed over a pair of ambulacral pores. The tube feet serve normally
as locomotive organs, when they are prehensile and end in a suctorial disk ;
but in many forms, especially thos'e having petaloid ambulacra, they are

XIV.), 1882-84.— Schliiter, C., Die regularen Echiniden der norddeutschen Kreide (Abhandl. zur
geolog. Special-Karte von Preussen, Bd. IV.), 1883. — Idem, Neue Folge, Heft 5, 1892. — de L<>ri<>h
P., Description des Echinides (Commission des travaux geol. du Portugal, vol. II.), 1887-88. —
Lwtn, S., On Pourtalesia (Svensk. Vetensk. Akad. Haudl., Bd. XIX.), 1884.— Pomel, N. A., Class-
ification methodique et genera des Echinides vivantes et fossiles, 1883. — Duncan. P. M., Revision
of the Genera and Great Groups of the Echinoidea (Journ. Linn. Soc., vol. XXIII.), 1889. — Ebert,
7*., Die Echiuiden des nord- uud mittel-deutschen Oligocans (Abhandl. zur geol. Spec. Karte von
I'reussfii, Bd. X.), 1889.— Loven, S., Echinologica (Bihang till Svensk. Vetensk. Akad. Handl.,
Bd. XVIII.), 1892.— Clark, W. B., Mesozoic Eohinodermata of the United States (Bull.- U.S. Geol.
Survey, No. 97), 1893.

2 1 2 ECHINODERMATA— ECHINOZOA SUB-BRANCH in

modified so as to be partly branchial in function. Sometimes the tentacles of
the same ambulacrum differ in shape, structure, and function, in which case
they are termed heteropodous. Small tufts of external branchiae communicating
with the ambulacral system are sometimes present, and occupy grooves or
incisions in the peristomial margin.

The vascular system consists of a ring-like vascular plexus surrounding the
oesophagus, and immediately underlying the circular ambulacral vessel. This
ring gives off five radial vessels, and also two others which send off branches
to the stomach and generative organs. The central nerve ring, with its five
principal nerves running down the rays, is external to the two other systems.
The generative organs are extremely alike in both sexes, and are in the form of
glands (usually five, sometimes three or even two), situated dorsally and
interradially on the inner surface of the test. The genital ducts terminate in
pores in the so-called genital plates, to be described presently.

Coronal Plates. — The plates of the corona are arranged in ten meridional
zones. Five of these, the ambulacral areas, are composed of perforated
plates, and correspond in position to the radiating ambulacral vessels ; the
remaining five, the interambulacral or interradial areas, alternate with the first,
and are imperforate.

In all recent, and in the majority of fossil Echinoids, the ambulacral
areas are composed of two rows of small, alternately arranged plates, the
inner edges of which meet in zigzag median sutures, and their actinal and
abactinal edges in horizontal sutures. The interambulacral areas are likewise
composed of two rows of plates, but they are generally larger than those of
the ambulacra, and meet them in ambulacro-interradial vertical sutures. There
are normally, therefore, twenty meridional rows of plates arranged in ten
alternating zones ; but this number is not fully attained in the Palaeozoic
Bothriocidaroida, and is exceeded in the remainder of the Palceechinoidea, in the
Triassic Tiarechinus, and in the Cretaceous Tetracidaris. The number of plates
is the same in all of the ambulacral and all of the interambulacral areas
respectively ; but the two systems are entirely independent of one another as
respects the size, shape, and number of the plates. In the Cidaridae, for
example, the ambulacra are very narrow, and are composed of from fifty to
sixty plates in each column ; the interarnbulacra are much broader, and con-
sist of four or five large plates in each column. In the regular Sea-urchins,,
or Endocyclica, all of the ambulacra and all of the interarnbulacra are similar ;
but in the Exocydica, the anterior ambulacrum and the posterior interambu-
lacrum often differ considerably from the corresponding areas.

Interambulacral (interradial) plates are always simple ; ambulacral plates
may be either simple or compound. In the latter case, they may be formed
of two or of several components, all of which are joined by sutures and form
a more or less geometrical plate. Most simple plates, and some of the
components are primaries — that is, they extend from the outer edge of an
ambulacrum to the median suture of the area. Demi-plates is a name applied
to those components which do not reach the median line.

The growth of the test in all Echinoids is effected by new plates being
successively added at the aboral termination of the ambulacra and inter-
ambulacra, and by their increasing in size and solidity. In the young
condition generally, and in the Clypeastroids and Spatangoids throughout
life, the interambulacra begin ventrally with a single plate, situated outside the

CLASS I

ECHINOIDEA 213

closed circle formed by the double column of paired ambulacral plates ; and
this solitary interambulacral plate is followed by a double column of
successively added plates, the last-formed being contiguous with the corre-
sponding basal of the apical system. But in the Endocyclica, according to
Love"n, the primordial interambulacral plate is soon resorbed," so that the
intfianil.ulacra enter the peristomial margin with two plates each.

Ambulacra. — Each ambulacrum consists of an interporiferous area, placed
between two poriferous zones ; only a few Palaeozoic genera have the whole
ambulacral area poriferous. As a rule, the ambulacral pores are in pairs ;
but in some cases they are unpaired. The pores may be either all similar,
or the outer pores of a series of pairs may differ in shape and size from those
of the inner series. There is usually a septum between the pores of a pair,
and the pairs may be separated by costae. When the pores of each pair are
united by transverse furrows, they are said to be conjugate.

The arrangement of the pairs of pores may be in simple series, when one
pair is placed over the other from peristome to apex; they are liserial
("bigeminal" auct.) when placed so that there are two vertical rows of pairs,
one nearer the ambulacro-interradial suture than the other ; and triserial
("trigeminal") when there are three vertical rows of pairs. Simple series of
pores are either absolutely straight, or in arcs of three or more pairs.
Oblique series are those in which there is an outward slant -of three or more
consecutive pairs from above downwards.

Ambulacra are simple or perfect when they are band-shaped and continuous
from pole to pole, or when the direction of the pairs of pores is but slightly
nexuous. Petaloid or circumscript ambulacra are those which enlarge between
the apex and equatorial circumference (ambitus), and contract again more or
less perfectly before reaching that region. Sub-petaloid ambulacra are more
elongated than the petaloid, and the pairs of pores do not tend to close
distally. The pores do not cease altogether at the end of the petaloid parts,
but remain traceable for some distance beyond, often as far as the mouth. In
such cases, however, the rows become uniserial, and the pores are greatly
reduced in size, or present other marked differences from those of the petaloid
parts. The poriferous zones are said to be discontinuous or interrupted when
the pairs of pores cease at the ends of the petals, and reappear in the vicinity
of the mouth. Sometimes the .dorsal portions of the ambulacra are petaloid,
and the rest simple, except often near the peristome.

Dorso-central or Apical System. — This is abactinal or dorsal, and is ordinarily
composed of ten plates arranged in two alternating zones or circles of five
plates each. The uppermost circle is interradially situated, and consists of
large pentagonal or hexagonal pieces, called the basal or genital plates. These
are usually perforated by one or more ducts communicating with the genital
glands ; but when less than the full number of glands are developed, the
corresponding basal plates are impunctate. The posterior basal is very often
imperfectly developed or absent. The lower circle of plates occupies the
summit of the ambulacra, and consists of five smaller radial plates (formerly
termed "ocular plates"), which are also perforated. In the Palceechinoidea
the radial plates may be pierced by more than one canal ; but all other
Echinoids have but a single canal to each radial, terminating in a single or
double orifice. These openings appear to relate to a primitive large tentacle,
and not to an ocular organ.

214

ECHINODERMATA— EOHINOZOA

SUB-BRANCH III

One of the basal plates, namely, the right anterior one, is generally larger
than the rest, and serves at the same time as the madreporic body. This
fact greatly facilitates the orientation, whenever the madreporite is preserved ;
unfortunately, however, it is indistinguishable in the majority of fossil speci-
mens. The anterior radial plate is that lying to the front and on the left
hand of the madreporite-bearing basal ; and it surmounts the odd or anterior
ambulacrum (Fig. 344, D). It is evident from the inspection of any Sea-

X

III III

FIG. 344.
Apical systems of A, Palceechinus. C, Salenia. D, Pdtastes, enlarged. The lAnib are designated I— V.

urchin that a plane passing through the odd ambulacrum, mouth, anus, and the
posterior interambulacrum, will divide the test into two symmetrical halves.

In the Exocydica the basal plates, may be in contact at their sides, forming
a compact si/stem (Fig. 345, B, D) ; or they may be separated by some of the

radial plates which
unite along the
median line and
push the posterior
basals backward,
forming an elongate
system (Fig. 3 4 5, C).
When the two pos-
terior ambulacra
(bivium) do not
terminate at the
summit in line
with the other
three (trivium),&ud
are surmounted by
radials placed far
posteriorly, the
system is said to
be disjunct or dis-
connected. The pos-
terior radials are

d^r1S;::"^;';:mIf ;^S"?i" 4S?^ B' Holectypus' • c' Hyl°- then separated

from the postero-

lateral basals by a number of interambulacral plates intercalated along the
dorsum (Fig. 345, A).

In the Clypeastridae, Holectypoida, and many of the Cassidulidae, the apical
system consists of five minute radial plates, and one large, pentagonal, central

FIG. 345.

CLASS [

ECHINOIDEA

215

which probably represents five fused basals, and is usually pierced in
four or in all of its interradial angles by genital pores (Fig. 345, E, F).

l'< riproct. — This is within the apical system in all regular Sea-urchins, and
at a variable distance beyond it in the median line of the posterior inter-,
ambulacrum when the test is exocyclic. The plates of the periproctal
membrane may be few and symmetrical, or numerous and irregular, and
arranged concentrically about the anal orifice. The Saleniidae have a large
suranal plate immediately in front of the latter. The periproct is usually
circular, but may vary from elliptical to pyriform. Its position on the test
is of great systematic importance.

Peristome. — This is more or less central and actinal in the Endocydica, and
is decagonal or pentagonal in contour ; and there are not infrequently five
or ten incisions along its edges for the reception of external branchiae.
In the Exocydica it is variable in shape and position, but is usually actinal,
and eccentric in front. Sometimes it is semilunar in outline, with a posterior

FIG. 34r,

Dental system of the recent Echinus
' rice, sfon from within the
test, a, Jaws or pyramids ; b, Tooth ;
c, Epiphysis or arcus ; d, Brace ;
e, Rotula or compass ; p, Peristome ;
(mi, Ambulacrum ; an, Auricles (after
Bert rand).

Dental apparatus of Sphuer echinus. A, View of the flat upper
surface. «, Half -pyramid with overlying pieces removed ;,//,<',
Epiphyses ; d, Brace (Zwischenkieferstiick) ; e, x, Rotulae or com-
passes ; w, Symphyses of the half- pyramids, with alveoli on the
inner face. The letters y and z mark the Amb and lAmb areas,
respectively. B, C, Half-pyramids seen sidewise and from within,
a, Lateral wings ; b, Tooth ; c, Supra-alveolar process.

labrum. Its plated membrane is attached to the pyramids of the jaws in
Gnathostomes ; otherwise the inner edge is free.

Around the peristome the pairs of ambulacral pores are often crowded. Or
they may form a kind of rosette, in which some of the pairs are wider apart
than others, and some are put out of place and doubled ; such an arrangement
is called a phijllode. In the Cassidulidae the phyllodes are sunken, and the
interambulacral areas between them are swollen so as to form lip-shaped ridges
(bourrelets buccaux), the whole forming a fioscelle about the mouth.

Jaws. — All Sea-urchins, with the exception of the Spatangoids, and pos-
sibly some of the Holectypoids, are provided with a powerful masticatory
apparatus, commonly known as "Aristotle's Lantern." In the Endocydica
(Figs. 346, 347) the system consists of five hard interradially situated teeth,
which are in relation with as many pyramids resting upon the peristome
internally, and whose free ends are capable of being moved towards one
another or apart. The pyramids form collectively a hollow cone or three-
sided pyramid, with the apex directed downwards, and the teeth slightly
projecting beyond the peristome. The pyramids are connected with one
another by muscles at their sides ; at their upper junction there are five

216

ECHINODERMATA— ECHINOZOA

SUB-BRANCH III

braces (fakes, Zwischenkieferstilcke) radiating outwards from the central axis of
the jaws ; and above each brace there is a long bifid process, the rotula or
compass (Gabelstuck). Each pyramid has an outer concave face, and two
flattened sides, forming a hollow groove in which the tooth runs. The teeth
are correspondingly grooved or keeled, pointed actinally, and are more or
less vertical.

The jaws of the exocyclic Gnathostomes are similar to those just described,
except in the Clypeastroids, where they are low, often unsymmetrical, and

the teeth are
aslant or even
nearly horizon-
tal (Fig. 348).
Rotulae are ab-
sent, and the
braces are rudi-
mentary. The
pyramids are
solid almost to
their upper
part, more or

A, Cl,
above.

reticulatus, Loven.
rotnlae are placed upor

FIG. 348.
Recent. The dental system entire, seen from

the sutures of adjoining pyramids, with an

p

piphysis on either side. Teeth in line with the mesial sutures of half-pyramids, and
nthin f~

within the ring formed by the supra-alveolar crests (after Loven). B, a, Front view
of a single pyramid. B, ft, Side view of one of the half-pyramids.

less concave, or
re-entering on
Jaws are rarely pre-

the outer side, and are not always of the same size.
served in the fossil state.

All Echinoids having a dental system are provided also with a perignathic
girdle (also termed auricles). This is a structure composed of ambulacral
processes and interambulacral ridges, which together surround and underlie
the jaws, and furnish attachment for their muscles. The girdle is continuous
when the ambulacral processes are arched over and connected at their sides
by ridges consisting of turned up and fused interambulacral plates ; and
discontinuous, as in Cidaris and the Clypeastroids, when there are either simple
ridges or simple processes without their union (Duncan). The girdle is
developed from the test itself, and does not therefore belong to the dental
system.

Tubercles and Spines. — The plates of Echinoids are almost always covered
with wart-like tubercles and granules, which carry various kinds and sizes of
spines. The larger and completely developed tubercles are called primaries;
those of a smaller size are secondaries; and very small tubercles, sometimes
incomplete in their development, are miliaries. Granules are irregular or
nodular projections of the test ; they may be large and widely separated, or
very numerous and of various sizes. The base of a tubercle is termed the
boss, and its upper part may be either plain or crenulated. The boss supports
a rounded mamelon, which is said to be perforated when pierced by a central
foramen for a slight distance, or imperforate when it is not. A plain or
sunken space surrounding the base of the tubercle is called the scrobicule, or
areole ; its outer limit, the scrobicular circle, is generally marked by a ring of
granules, but in many cases the scrobicules of the same meridian are con-
tinuous. Secondary tubercles may or may not be scrobiculate.

All the tubercles of Sea-urchins bear movable spines, which vary greatly
in dimensions, and in the shape and nature of their cross-sections. They are

<M..VSS I

ECHINOIDEA

217

Cidarid Spines.
E, Porocidaris.

FIG. 349.
A, B, Cidaris. D, Acroc'tilm-l*.

usually cylindrical, acicular, clavate, or spatulate in form, and consist of the
following parts : — A more or less elongate distal portion or shaft; a base, to
which ligaments are attached for keeping the spine in place; and an articu-
lating joint or condi/le (acetabulum), forming a ball and socket joint with the
tubercle proper. When the base of the mamelon is crenulated, the base of
the spine is incised in the same manner,
and above the latter is usually a milled
ring or collar, the indentations of which
are continuous with the striae of the
shaft. The function of spines is to
support the test, to aid in locomotion,
and for defence. In rare cases some
of the spines are fixed, and arise
directly from the test (Podocidaris).

Fascioles are narrow bands of close
granular ornamentation which support
rudimentary spinules and pedicellariae.
They occur only in the Spatangoids,
and are restricted to certain parts of
the test. The peripetalous fasciole
follows the margin of the petaloid
parts of the ambulacra. The anal
fasciole surrounds the anus, and the
subanal fasciole encloses a space or
plastron beneath the anus, but may send anal branches upward. The internal
fasciole crosses the ambulacra at a variable distance from the apical system,
and the marginal fasciole encircles the test above the ambitus. For
those Spatangoids with subanal fascicles, Loven has proposed the name
Prymnodetmia; genera without them, and with other fascicles, are Prymnadetes,
and those without any fascicles are Adetes.

Pedicellariae are small, highly specialised spines articulated upon granules,
and scattered in between the spines proper over the whole surface of the test.
At the end of the stem is a head consisting of two or three pincer-like valves,
whose office is to catch up and pass along foreign matter that has become
entangled among the tubercles and spines.

Spheridia are opalescent spheroidal bodies which are either placed visibly
upon short stalks, or are partially or even entirely covered by the test. They
occur in all Echinoids with the exception of the Cidaridae, belong exclusively
to the ambulacra, and are found usually near the peristome. Anatomically
the spheridia may be considered as modified spines having sensory functions,
probably of taste or of smelling.

Ontogeny. — The early ontogenetic stages of Sea-urchins are similar in many
respects to those of Ophiuroids and Star-fishes, but have little in common with
the larvae of Crinoids. Certain changes affecting the test during the course
of its development are of great morphological interest, such as the formation
of tubercles, variations in the number of plates in the Ecliinidae and other of
the Regulares, the transformation of simple ambulacra into petaloid in the
Echinolampidae ; the migratory character of the periproct in many Cassiduloids,
•etc. Much light is shed upon these phenomena by comparison with fossil forms,
many of which retain permanently features which are now exhibited transitorily.

218 ECHINODERMATA— ECHINOIDEA SUB-BRANCH m

Homologies. — The Echinoidea differ radically from the Pelmatozoa and
Asterozoa in that arms are completely wanting ; and although the principal
viscera (ambulacral, blood, nervous, and digestive systems) are similarly
formed and situated, the dermal skeleton, on the other hand, is very differently
developed in the three groups. The ambulacra of Echinoids are without
arm supports, vertebral disks, or ambulacral ossicles. The system is confined
to the interior of the test, arid is covered over with plates which are possibly
comparable with the adambulacral plates of the Pelmatozoa and Asteroidea.
Great phyletic importance was attached by A. Agassiz, Loven, and P. H.
Carpenter to the homology between the dorso-central system of Sea-urchins
and the base of Pelmatozoans ; the basals and radials of that system being
supposed to correspond to the like-named plates of Crinoids ; and the large
central plate developed in the periproct of young Eegulares (the so-called
dorso-central plate) was regarded by Loven and others as the solidified homo-
logue of five crinoid basals or under-basals, whilst Carpenter considered it to
be the equivalent of the radical plate or root-disk at the extremity of the
Crinoid stem. Neumayr, Semon, and others have, however, advanced weighty
arguments against this hypothesis, and regard all of the above-mentioned
resemblances as cases of parallelism.1

Habits. — Sea-urchins are exclusively marine forms, and all are more or
less gregarious. Many species abound in littoral zones, some thriving on the
edge of low-water mark (Clypeastridae). Others are found in zones ranging
from 400-600 fathoms (Diadematoidea), and a few have been dredged from a
depth of nearly 3000 fathoms. Numerous endocyclic Sea-urchins, along
coasts exposed to the action of the waves, live in cavities which they bore
with their teeth out of the solid rocks. The same species, however, does riot
excavate in sheltered places.

About 300 recent species are known, as compared with fully 2500
fossil. The earliest types make their appearance in Ordovician rocks
(Bothriocidaris), and continue to be represented sparsely throughout the
Palaeozoic era. They multiply enormously in the Mesozoic, and reach the
climax of their development in the early Tertiary; after which they begin
steadily to decline. As a rule, the species have a very limited vertical range,
and hence serve admirably as index fossils. The test is often perfectly pre-
served, but even small fragments are capable of accurate determination, owing
to the regular repetition of isomeres.

The number of meridional rows of plates in the corona is used as a
basis for dividing the Echinoidea into two sub-classes — Palwechinoidea and
Euechinoidea.

Sub-Class 1. PAUEECHINOIDEA. Zittel.

Test composed of more than twenty meridional rows of plates, or in one order
(Bothriocidaroida) of less than twenty. Plates of the areas overlapping or not.
Peristome actinal, central, with jaws. Periproct within the dorso-central system or
in the posterior inter ambulacrum beyond (Cystocidaroida).

With the exception of the Triassic Tiarechinus, all members of this sub-class
are restricted to the Palaeozoic era.

1 [For valuable notes on the homologies of Echinoderms, see Agassiz, A., Calamocrinns Diomedae
(Mem. Museum Comp. Zool. Cambridge, vol. XVII. pp. 84-96), 1892. — TRANS.]

ORDER i PAL^ECHINOIDEA— PERISCHOECHINOIDA 219

Order 1. CYSTOCIDAROIDA. Zittel.

Test exocyclic, globular or ovoid, thin. Ambulacra narrow, straight, with four
r, ,iir,il rows of plates, each with a central pair of pores. Interambulacra broad,
?/•/'/// n n-merous vertical rows of irregular, scale-like plates, each with a small primary
tubercle surrounded by a scrobicule. Periproct in the posterior interambulacrum
above the ambitus. Peristome small, with highly-developed jaws.

Echinocystites, Wyv. Thorns. (Cystocidaris, Zitt.) This aberrant genus, with
the characters of the order, occurs in the Silurian of Scotland, and was regarded
by its founder as transitional between the Echinoidea and Cystoidea.

Order 2. BOTHRIOCIDAROIDA. Zittel.

Test regular, more or less spherical. Interambulacra with one, and ambulacra
•//•//// two vertical rows of plates, which do not imbricate. Periproct in the apical
system.

The solitary genus is Bothriocidaris, Eichwald (Fig. 350), from the Ordo-

FIG. 350.

s Palilcni, Schmidt. Ordovician ; Nommis, Esthonia. A, Test of the natural size. B, Apical
system, enlarged. (7, Peristome, enlarged (after F. Schmidt).

vician of Esthonia. The test is small, and the apical system consists of five
large radial plates limiting the periproct, each with two pores ; and five small
imperforate basal plates.

Order 3. PERISCHOECHINOIDA. M'Coy.

Test regular, globular or ovoid, with more than two vertical rows of interam-
bulacral plates' ; and with two or many columns of ambulacral plates, each with a
pair of pores. Plates thick and rigid, or thinner and more or less overlapping.

Family 1. Archaeocidaridae. M'Coy.

Ambulacra narrow, each with only two columns of poriferous plates. Interam-
Inihh'ral plates with levelled edges, and usually overlapping. Devonian to Permian.

Lepidocentrus, Miiller (Fig. 351). lAmb with five to eleven columns of plates
at the ambitus. Amb very narrow, with low broad plates, and continued
beyond the peristomial margin to the true mouth. Tubercles distant ; spines
small, subulate. Devonian ; Europe.

220

ECHINODERMATA— ECHINOIDEA

SUB-BRANCH III

Koninckocidaris, Dollo and Buiss. Europe. Perischodomus, M'Coy. Car-
boniferous ; Europe and North America.

Archaeocidaris, M'Coy (Palaeocidaris, Desor), (Fig. 352). Test large. Amb
straight, reaching to the stoma ; plates irregular, imbricating adorally. I Amb

FIG. 351.

A, Lepiiloreittnix llhenamis, Beyr. Devonian ; Wipperfiirtli, Eifel. Cast of the interior of test showing jaws,
l/i (after J. Muller). B-D, Lepidocentrus Mullen, Schultze. Devonian ; Gerolstein, Eifel. J3, Portion of Amb,
enlarged. C, Several lAmb plates, 1/1- A Two detached I Amb plates, showing oblique edges, i/j.

with three to seven columns of large thin plates, the median ones hexagonal, the
adambulacral pentagonal or rounded. Median plates bevelled slightly over
those on either side, and these over others to the ambulacral edge. Each lAinb

FIG. 352.

Archaeocidaris Wortheni, Hall. Sub-Carboniferous ; Burlington, Iowa. A, Portion of ventral region, showing
jaws, Vi- -B, An I Amb plate viewed from above and from the side. C, Portion of Amb, enlarged. D, Spine, J/i
(after Hall).

plate with a large primary tubercle, surrounded by a large flat scrobicule and
a circlet of granules. Primary spines large, usually serrated. Carboniferous
Limestone ; Great Britain and North America. Permian • England.

Lepidocidaris, Meek and Worthen. Sub-Carboniferous ; North America.
Lepidechinus, Hall. Upper Devonian and Sub-Carboniferous ; North America.

Xenocidaris, Schultze. Founded upon clavate spines from the Devonian of
the Eifel.

oi;m:n in

PAL.KKCmXOIDKA — I'KIUSCHOKCIIINOIDA

221

FIG. 353.

Palceechinus elegans, M'Coy. Carboniferous Limestone ; Ireland.
A, Test, Vi- -B> Apical system, enlarged (after Baily).

Family 2. Melonitidae. Zittel.1

Ambulacra more or less broad, composed of several columns of poriferous plates
in all genera except Palceechinus ami Ehoechinus, where there are but two. Car-
boniferous.

Palceechinus (Scouler), M'Coy (Fig. 353). Test spheroidal, rigid. Amb
straight, composed of two vertical rows of low thick plates, extending
across the half Amh or not.
Pairs of pores in two ver-
tical rows on each side of
an Amb; the outer pairs
either in demi- plates or
primaries; the inner pairs
always in primaries, which
may, however, be short.
lAmb broad, convex, with
five to eight columns of
tumid plates, diminishing
toward the poles. Peri-
proct in apical system, sur-
rounded by five large basal
plates, each perforated by
one or three canals, and five doubly perforated radial plates. Silurian ;
England. Carboniferous Limestone ; Great Britain.

PJwechinus, Keeping. Like the preceding, but ambulacral plates never
compound, and only one vertical row of pore pairs on each side of an Amb, a
pair to each plate. lAmb with four to eight columns of plates diminishing
toward the poles, slightly overlapping. Radials sometimes wanting. Car-
boniferous Limestone ; Great Britain. Sub-Carboniferous ; North America.

Oligoporus, Meek and Worthen. Like Melonites, but Amb with only four
columns of plates, and lAmb with five to nine columns at the ambitus, diminishing
in number toward the poles. According to Jackson, the interambulacral plates
develop like those of Melonites. The Amb terminate at the peristomial margin
in two plates, which pass gradually by lateral expansion into the four columns
of the adult. Sub-Carboniferous ; North America.

Melonites, Norwood and Owen (Fig. 354). Test very large, ellipsoidal,
grooved longitudinally. Amb broad, concave on both sides of a median ridge,
with six to twelve columns of plates, each perforated near its outer border by a
pair of pores. Plates slightly imbricated, the median rows the largest. lAmb
with four to eleven columns of plates, diminishing in number toward the poles.
The median plates are hexagonal ; the two rows adjacent to the Amb pentagonal,
with the edges indented by the zigzag of the ambulacro-interradial suture.
Edges of plates sometimes oblique, especially when thick. Tubercles very

1 Roemer, F., Ueber den Bau von Melonites multipora (Arch, fur Naturgesch. Bel. XXI.), 1855.
EtJieridge, R., On Relationships between the Echinothuridae and Perischoechinidae (Quar. Journ.

QeoL Soc. vol. XXX.), 1874.

Keeping, IV., On the Discovery of Melonites in Britain (Quar. Journ. Geol. Soc. vol. XXXII.), 1876.
Duncan, P. M., On the Anatomy of Palseechinus (Ann. and Mag. Nat. Hist. [6] vol. III.), 1889.
Keyes, G. R., Palaeozoic Echiuodermata (Proc. Iowa Acad. Sci. vol. II.), 1894.
Jackson, R. T., and Jaggar, T. A., Studies of Melouites multiporus (Bull. Geol. Soc. America,

VII.), 1896.
Jackson, R. T., Studies of Palseechinoidea (Bull. Geol. Soc. America, VII.), 1896.

222 ECHINODERMATA— ECHINOIDEA SUB-BRANCH m

small, numerous ; spines minute, acicular. Periproct circular ; basal plates

FIG. 354.

Melonites multipora, Norwood and Owen. Sub-Carboniferous ; St. Louis, Missouri. A, Test, */•> natural size.
7J, Dorso-central system, slightly enlarged (after Meek and Worthen).

with three to five genital perforations ; radials sometimes with a single pore.
Sub-Carboniferous ; North America and Europe.

[As shown by Jackson and Jaggar (Studies of Melonitidae), the lAmb of Melonites
enter the peristomial margin as two plates. Passing dorsally, new columns are introduced,
rapidly at first, until the full complement is reached at or a little above the ambitus. The initial
plates of new columns are pentagonal, with a more prominent apex of the pentagon pointing
ventrally ; and an adjacent plate is characteristically heptagonal, thus facilitating the orienta-
tion of obscure fragments. Newly added plates near the dorsal area are more or less rhombic
in outline. The Amb terminate actinally in four plates ; and new vertical columns are added
between the median and lateral columns on either side, increasing dorsally.]

Lepidesthes, Meek and Worth. Test large. Amb broad, with eight to
eighteen columns of small plates imbricating adorally ; and pores in single,
or occasionally in double pairs. lAmb with three or more columns of plates
imbricating aborally and laterally. Sub-Carboniferous ; North America.

Hyboechinus, Worthen and Miller ; Pholidocidaris, Meek and Worthen.
Sub-Carboniferous ; North America.

Family 3. Tiarechinidae. Zittel.

Ambulacra narrow, with two vertical rows of plates pierced by a pair of pores.

Interambulacra with a single peristomial plate,
followed by three vertically elongated plates only,
one on either side of the narrower median plate.
Basals large, with two genital perforations;
radials smaller, imperforate, and notching the
union of the basals slightly.

Tiarechinus, Neumayr (Fig. 355). The test
of this unique genus is very small, flat actinally,
weeps, Laube. upper Trias; and sub- hemispherical dorsally. Below the
ambitus and actinally the ornament consists
of a plain primary tubercle to each plate ; else-
where the test is coarsely granular, including the very large apical system. The
solitary species, T. princeps, Laube sp., occurs in the Trias of St. Cassian, Tyrol.

FIG. 355.

Tiarechinus pri

St. Cassian, Tyrol." "Ventral and lateral
aspects, highly magnified (after Loven).

SUB-CLASS ii i-:r !•:< 'in NOI DEA— ci DAHOI DA 223

Sub-Class II. EUECHINOIDEA. Bronn.

Test composed of two vertical rows of plates in all of the ambulacra and inter-
Periproct either within the dor so-central system or in the posterior infer-
ambulacrum at a variable distance beyond. Peristome actinal, rarely anterior.
Jaws present or «/»*•«/. Permian to Recent.

The older division into tin- tw.. ..nln-s of Desor, 7,v,///A/,-.x ami I <• rcgulares ( = Erulocyclica
and Exocy/i'<-'i, Wright), with tln-ir further division into two sub-orders each (HolostomaUi and
Ghjphostomata of tlii- riidnrv.-lii-, and Gnatlwstomata and Atelostomata of the exocyclic orders),
is now superseded by the erection of five independent orders, as follows -.—Cidaroida, Diadema-
toida, Hoi, ,-hiiu)ida, Clypeastroida, and Spatangoida. Of these the first two correspond to the
Rcgulares, and the remainder to the Irregulares.1

Order 1. CIDAROIDA. Duncan.

" Euechinoidea with an actinal, central peristome and an abactinal periproct,
situated within the dorso-central system ; with internal branchiae only, and having
jiui-x and more or less vertically placed teeth, and a discontinuous perignathic girdle;
the interambulacral as well as the ambulacral plates continued beyond the peristome to
the true mouth. Spheridia absent " (Duncan).

Family 1. Cidaridae. Wright.

Test spheroidal ; the ambulacra narrow, composed of very numerous low plates,
which are usually primaries, rarely compound, each with a pair of pores arranged in
single or rarely in double series ; interporiferous areas with large and small granules
only. Interambulacra broad, composed of few plates, most with a large primary
scrobiculate tubercle, secondaries and granules. Apical system large, with five basal
and five radial plates, each with a perforation. Permian to Recent ; maximum in
Jura and Cretaceous.

SECTION A. AMBULACRAL PAIRS OF PORES UNISERIAL.

Cidaris, Klein (Figs. 356-358). Amb undulating or nearly straight, the
pores variable in their distance, and united by a groove or not. I Amb coronal
plates five to eleven in each column. Apical system large. Primary spines
very variable, even in the same species. Permian to Recent ; chiefly Jurassic
and Cretaceous.

Of this genus more than 200 species have been described. These are grouped into seven or
eight artificial divisions, which are regarded by some as of sub-generic, or even generic import-
ance. The groups may be briefly noticed as follows : —

1 [The progress of the zoology and morphology of the recent Echinoidea during the last couple
of decades has been such as to necessitate numerous changes in the older terminology and classifi-
cation. The framing of an improved system, based \ipon the new grounds and expressive of the
modern views entertained in regard to taxonomic relationships, was the last undertaking of the late
Professor P. Martin Duncan. His essay on the " Revision of the Genera and Great Groups of the
Echinoidea," published by the Linnean Society, has been of the greatest service in extending the
descriptions of numerous fossil genera in the present chapter. Following the example of Lang and
others, Professor Duncan's classification has been adopted almost entirely. A word of special
acknowledgment is also due to Mr. W. Percy Sladen, for his advice and generous assistance in
editing this portion of the Echinodermata. — TRANS.]

224

ECHINODERMATA— ECHINOIDEA

SUB-BRANCH III

(a) Cidaris, s. str. I A mb coronal plates five to eight. Amb more or less undulating ; pairs
of pores rather close, separated by a nodule or ridge. Primary tubercles perforated and
crenulated.

(b) Rliabdocidaris, Desor (Fig. 359). Test large and swollen. Poriferous zones wider than

FIG. 356.

Cidaris coronata, Goldf. Upper Jura (y) ; Hossingen, Wurtemberg. A, Dorsal aspect of test with perfectly
preserved apical system. B, Profile. C, Portion of Amb, magnified. D, Partially restored view with spines
attached.

ill Cidaris, the two pores of a pair being distant and conjugated. Amb in general straight.
Tubercles large, strongly crenulated, and more numerous than in Cidaris. Spines very stout,

Fro. 357.

Cidaris tribuloiiles, Lnm. Recent. Enlarged view of peristome
showing plated covering.

FIG. 358.

Cidarid spines. A,
C. alata, Ag. B, C,
dorsata, Braun. Trias ;
St. Cassian, Tyrol. C,
C. florigemma, Phill.
Coral Rag ; Wiltshire.

some cylindrical or prismatic, often spiniferous. Chiefly Jura and Cretaceous ; less common in
Tertiary and Recent.

SUB-CI

EUECHINOIDEA— CIDAROIDA

225

(c) Lciocidaris, Desor. Like the preceding, l>nt with uncrenulated tubercles. Spines large,
smooth, cylindrical. Cretaceous to Recent.

(d) Dorocidaris, A. Ag. Like ('i,l,i,-is, but with smooth tubercles. Recent.

(e) Stephanocidaris, A. Ag. Test thin : apieal system larger than the peristome, the plates
feebly united, and the whole flexible. Recent.

(/) Phyllacanthus, Brandt. Test large, swollen, and with eight to eleven IAmb plates. Afnb
pores in a broad zone, conjugated. Primary tubercles large, smooth, perforate. Recent.

(if) Poi'ociilnri*. I -".til). Amb broad and straight ; pores wide apart, conjugated.

Primary tubercles perforate and crenulate. Scrobicules transversely oval, with shallow grooves
radiating from the periphery toward
the centre, with or without pores at \ A

the outer extremity of the grooves.
Tertiary and Recent.

(ft) Gfoniocidarii) Desor. Test hi^h.
with numerous coronal plates, and
narrow Amb. The median sutural
regions of both areas are sunken, form-
ing with the horizontal sutures a zig/ag,
with pit-like depressions at the angles.
Recent.

Orthocidaris, Cott. Apical
system small, pentagonal. Amb
narrow, straight ; pairs of pores
in simple straight series, the
d^roarated by a granule.
/ M Mrv broad, numerously
plaft(PPrimary tubercles small,
plain, perforate, and distant.
Lower Cretaceous ; Europe. pio yQ

Temmcidaris, Cott. Upper RhaMocid,iris ^Or^nyana, Desor.

OretaceOUS. PolmidariS, Ouenst. uPPer Jura: Kelheim-Winzer, Bavaria.

TT T -A, Fragment of test, i/!. B, Ami plates,

Upper Jura. enlarged.

SECTION B. AMBULACRAL PAIRS
OF PORES BISERIAL.

Diplocidaris, Desor. Test
large, spheroidal. Amb narrow,
straight ; poriferous interporifer-
ous zones of equal width. Pairs
of pores very numerous, close,
alternating more or less. IAmb
broad, with seven to eight plates
in each column. Primary tubercles
large, perforate, scrobiculate.
Upper Jura ; Europe.

Tetracidaris, Cott. (Fig. 362)
Remarkable in having four Forocidaris SM,eli> Goldf Nummu.

Coronal plates in each IAmb at litic Limestone; Mokkatam, near Cairo.

the ambitus, but diminishing to ' d Bpine'

two at the apex. [It should be noticed, however, that A. Agassiz has observed
a somewhat similar division in the IAmb plates of the recent genus Astropyga 1
Amb straight, moderately broad. Poriferous zones depressed, pairs incom-
pletely biserial ; interporiferous areas narrow, granular, with a row of plain

VOL. I

FIG. 361.
Porociclaris Schmieileli, Goldf. Nummu-

FIG. 360.

Rhabdocitlaris
horrida, Merian.
Middle Jura.
Spine, l/i-

226 ECHINODERMATA— ECHINOIDEA SUB-BRANCH m

small tubercles, placed near the borders of the poriferous zone. I Ami) primary

FIG. 362.

Tetracidfiris Reynesi, Cotteau. Neocomian ; Vergans, near Castellane, Basses Alpes. A, Test reduced one
half. B, Portion of Amb, enlarged (after Cotteau).

tubercles very large, crenulate, and perforate. Spines narrow, elongate.
Lower Cretaceous (Barremien) ; Europe.

Order 2. DIADEMATOIDA. Duncan.

" Euechinoidea with an actinal, central peristome, and an abactinal periproct
situated within the dor so-central system; with perfect or rudimentary or absent
internal branchiae, with external branchiae and incisions in the peristome ; with jaws
and teeth and a continuous perignathic girdle; ambulacral plates alone continued
beyond the peristome or as separate buccal plates. Spheridia present." — Duncan.

Sub-Order A. STREPTOSOMATA. Duncan.

Test more or less flexible, with external and internal branchiae. Ambulacral
plates alone continued beyond the peristome to the stoma.

Family 1. Echinothuridae. Wyville Thomson.

Test thin, flexible. Coronal plates with imbricating membraneous edges. External
branchiae small, internal sometimes very large. Tubercles small; spines short,
cylindrical.

This family is represented by two living and two extinct genera, the latter
being known only by fragmentary specimens. Pelanechinus, Keeping, is found
in the Upper Jura, and Echinothuria, Woodward, in the Upper Cretaceous of
England. Phormosoma, Wyv. Thomson, and Asthenosoma, Grube (Calveria,
Wyv. Thomson), inhabit depths greater than 100 fathoms.

Sub Order B. STEREOSOMATA. Duncan.

Test rigid, with external branchiae and rudimentary or absent internal branchiae ;
with isolated buccal ambulacral

ORDER II

EUECHINOIDEA— DIADEMATOIDA

227

Family 1. Saleniidae. Desor (emend. Duncan and Sladen).

Apical system large, with a persistent dwso-central plate or plates, which crowd
the anal orifice somewhat out of the centre of the periproct. Ambulacra narrow, with
a n merous, simple, low primaries ; rarely compound actinally. Interambulacral plates
few, with large tubercles. Teeth keeled. Spheridia present. Jura to Recent.

The pivsenrr ,,f on.- or more dorso-central plates in the apical system is to be regarded as a
persistent embryonic character. In all other regular Urchins, a large dorso-central plate is early
developed, but becomes gradually resorbed.

Peltastes, Ag. (Fig. 344, D). Ami straight or slightly flexuous, with simple
plates, and with small primary tubercles near the poriferous zones. I Amb
broad, with large, imperforate primary
tubercles, diminishing in size toward
the poles. Dorso-central plate small,
united to the large lateral basals, but
not touching the posterior one. Upper
Jura and Cretaceous.

tiilcnia, Gray (Fig. 363). Test
small, globose, or depressed. Amb
plates simple. Dorso-central plate in
coiitact with all the basals ; radials
large, perforated at the adoral edge.
Cretaceous to Recent. ^mnr" FIG. 303.

Goniophorus, Agassiz. Upper
Greensand. Heterosalenia, Cotteau.
Cretaceous.

.li-rosalenia, Ag. (Fig. 364). Test depressed. Amb plates simple primaries
near the apical system, compound near the ambitus and actinally. lAmb
tubercles large, perforate, and crenulate ; those of the Amb much smaller, and

Salenm scutigem, Gray. White Chalk ; Chareute
after Cotteau). A, Lateral and dorsal aspects of test
./i. J5, Apical system, enlarged.

Fio. 364.

Acrosalenia temicidaroides, Wright. Middle Jura ; Stanton, Wiltshire. Dorsal, lateral, and ventral aspects
of test, i/, (after Wright).

in two vertical rows. Periproct large, bounded anteriorly by the dorso-central,
which is in contact with the four large anterior basals. Spines cylindrical,
striated, or plain. Represented by numerous species from the Lias to the
Lower Cretaceous.

Family 2. Hemicidaridae. Wright.

Test thick, more or less spheroidal or sub-conical. Ambulacra increasing in
width actinally ; the pairs of pores in arcs actinally where the plates are compound ;

228

ECHINODERMATA— ECHINOIDEA

SUB-BRANCH III

primary tubercles well developed. Interambulacral plates few ; their primary tubercles
very large at the ambitus, but decreasing in size or obsolescent toward the poles ;
scrobicules often coalescing. Permian to Cretaceous.

Hemicidaris, Ag. (Fig. 365). Amb narrow ; plates
near the apical system very numerous, small, low
primaries, succeeded by plates formed of from two
to four components, together with additional primary
or demi-plates. Tubercles in two vertical rows, per-
forate and crenulate. I Ami) broad, with two vertical
rows of tubercles similar to those of the Anib, but
much larger. Peristome large, with well-developed
„«„«,«„ ^ Lam. branchial incisions. Permian to Cretaceous.

sp. Coral Rag; Chatel Censoire, mi .. ,, . ,

Yonne. ty. The following sub-genera are recognised : —

(a) Hemidiadema, Ag. Amb tubercles large, and few in number below the ambitus,
alternating distinctly. Jura and Cretaceous. H. stramonium, Ag.

FIG. 365.

Is CTenuh'ris.

FIG. 366.

Acrocidaris nobllis, Ag. Upper Jura ; St. Sulpice, near Locle, Neuchatel. A. Dorsal view. B, Ventral
view. C, Spine, 1/1- D, Three compound Amb plates, enlarged.

' (b) Hypodiadema, Desor. Amb narrow, straight ; their tubercles of nearly the same size
throughout. Peristome and branchial incisions small. Trias to Cretaceous.

(c) Pseudocidaris, ]£tall. Amb very undulating abactinally, with
primary tubercles near the peristome, granules elsewhere. Jura and
Cretaceous.

Acrocidaris, Ag. (Fig. 366). Test large, spheroidal
dorsally, flat actinally. Amb straight, broad at the ambitus ;
pairs of pores uniserial and in simple series near the apex,
in arcs of from four to seven pairs near the larger tubercles,
crowded and polyserial actinally. lAmb with two vertical
rows of primary tubercles; only the largest perforate and
crenulate. Spines cylindrical, often tricarinate. Upper
Jura and Cretaceous.

Goniopygus, Ag. Apical disk large, plates more or less
ornamented ; basal plates punctured on adoral margin. Peri-
stome very large, with small branchial incisions. Cretaceous
and Eocene.

Glypticus, Ag. (Fig. 367). Amb straight, and narrow except at the peri-
stome, where the poriferous zones are expanded ; with two vertical rows of

Fid. 367.

Glypticus hierogl
icus, Goldf. Coral Rag
(Glyptician) ; Fringeli,
Switzerland. 1/1-

lyph-
IRae

ORDER II

EUECHINOIDEA— DIADEMATOIDA

229

small, smooth, primary tubercles. lAmb tubercles replaced abactinally by
warty or irregular elongate elevations. Epistroma much developed. Abun-
dant in Upper Jura.

Family 3. Diadematidae. Wright.

Test Uighbj ormnwnfeil, hnnlil, depressed, or spheroidal Ambulacra straight,
moderately broad or narrow, with vertical
rows of small primary tubercles, and com-
pound plates near the ambitus and actin-
ally. Interambulacra broad, with numer-
ous low plates; the rows of primary
fill" rdes diminishing in number dorsally.
Peristome large, polygonal. Lias to
Recent.

Sub-Family A. DIADEM ATINAE.

Ambulacral plates compound near the
tinnitus; pairs of pores in simple vertical
3 or in arcs of three.

Desor), (Fig. 368). Amb narrow, often
projecting ; two vertical rows of small,
primary, crenulate, and perforate
tubercles extending from peristome
to apex. I Amb with two or more

" . Dlndfiina (Pseudodiadcma) negleclum, Tlumn. From

vertical rOWS OI primary tubercles the Bernese Jura. A, Ii, Profile and ventral aspect of
resembling those Of the Amb, but tCSt'1/1' <?, Ambulacrum, enlarged. A Spine, Vi.

larger. Secondary tubercles and granules surrounding the scrobicules.
Spines long, hollow, longitudinally striated. Lias to Recent.

Duncan has shown that the separation of the fossil species from the recent under Desor's
term of Psciidodiadema is a purely artificial distinction. The following sub-genera are

? 3 fl J A T .^ T)-J-~ . . T> If! ?_• -7 /"1-A.L T' T\ • 7

recognised: — Centrostejjfianus, Peters ; Recent.
A a

Microdiadema, Cotteau ; Lias. Diademopsis,

Fio. 369.

Codiopsis doma, Desm. sp. Cenomanian (Tourtia) ; Tournay, Belgium. A. Side-view of test, Vi- A Ventral
aspect of same. C, Apical system, enlarged.

Desor ; Lias. Echinodiadcma, Cotteau ; Upper Jura. Hemipedina, Wright ; Jura, Cretaceous,
and Recent. The latter differs from Diadema in having simple Amb plates near the apex,
and perforate, but not crenulate tubercles.

Heterodiadema, Cott. Like Diadema, but with the apical system greatly

230

ECHINODERMATA— ECHINOIDEA

SUB-BRANCH III

extended into the depressed posterior lAmb. Pairs of basal plates separated
by the antero-lateral radials, the fifth basal absent. Cretaceous. H. libycum,
Cotteau.

Codiopsis,' Ag. (Fig. 369). Primary tubercles of both areas small, smooth,
nearly equal in size, and only occurring actinally and for a short distance
toward the ambitus. Pairs of pores uniserial. Cretaceous.

Cottaldia, Desor. Cretaceous and (?) Recent. Pleurodiadema, de Loriol.
Jura. Magnosia, Michelin. Jura and Cretaceous.

Sub-Family B. DIPLOPODIINAE.

Ambulacral plates compound ; pairs of pores biserial.

Diplopodia, M'Coy. Amb narrow, with two vertical rows of perforate and
crenulate primary tubercles. Pairs of pores in double vertical series near the
poles, uniserial at the ambitus. Jura and Cretaceous.

Pedinopsis, Cotteau. Cretaceous. Phymechinus, Desor. Jura.

Sub-Family C. PEDININAE.

Ambulacral plates compound; pairs of pores triserial.

Pedina, Ag. Amb narrow, poriferous zones wide. Both areas with two
vertical rows of small, perforate, primary tubercles. Upper Jura.

Una, Cott. Like the preceding, but with larger primary

FIG. 370.

Stomechinus lineatus, Goldf. sp. Coral Rag ; Sontheim, Wurtemberg. A, Side-view of test,
of actinal surface.

B, Portion

Upper

tubercles, which are present in the Amb near the ambitus only.
Jura.

Micropedina, Cott. Amb with several, and lAmb with numerous vertical
rows of very small primary tubercles. Cretaceous.

Stomechinus, Desor (Fig. 370). Distinguished from Pedina by its wider
Amb, and imperforate, non - crenulate, primary tubercules. Secondary
tubercles and granules often present. Jura and Cretaceous.

Codechinus, Desor. Tubercles very small, plain, Irregularly distributed.
Cretaceous.

Polycyphus, Ag. Jura. Astropyga, Gray. Recent.

ORDER II

EUECHINOIDEA— DIADEMATOIDA

231

Sub-Family D. ORTHOPSIXAE.

Ambulacra with simple primary plates ; pairs of pores in simple series.
Orthopsis, Cott. Amb much narrower than the I Amb, straight, and with
numerous pairs of pores in straight series. Amb with two, lAmb with several
vertical rows of small, plain, perforate tubercles. Jura and Cretaceous.

Eodiadema, Duncan. Lias ; England. Echmopsis, Ag. Eocene ; Europe
and Egypt.

Family 4. Cyphosomatidae.

Test highly ornamented, moderate in size. Ambulacra with high compound plates,
each with three to seven pairs of poi'es in an arc; the pairs sometimes biserial near
the apical system, and crowded near the peri-
stome. The adoral and supra-adoi-al com-
ponents of the plates are primaries, and the
others demi-plates. Ambulacra with two
vertical rows of primary tubercles ; interam-
Imlacm with a variable number. Jura to
Recent.

Cyphosoma, Ag. (Fig. 371). Test de-
pressed, with few coronal plates. Amb'
with well-developed poriferous zones,
undulating. Pairs of pores biserial at
the apex, crowded at the peristome.
Limb broader than the Amb, with two or
more vertical rows of primary tubercles,
which are imperforate and crenulate,
like those of the Amb. Apical system
encroaching upon the posterior I Amb.
Jura to Recent.

Micropsis, Cott. Amb with three to five pairs of pores to a compound
plate, and two or more vertical rows of small primary
tubercles, which are perforate and crenulate. Cretaceous
and Eocene.

Family 5. Arbaciidae. Gray

Test depressed dor sally, flat actinally. Ambulacra narrow,
straight, expanding near the peristome, with compound plates
near the ambitus. Pairs of pores simple or in large arcs,
sometimes crowded actinally. Interambulacra with few or
several vertical rows of imperforate, non-crenulate, primary
tubercles with expanded bosses. Tertiary and Recent.

Arbacia, Gray. Tertiary and Recent. Echinocidaris,
Duncan and Sladen (non Desmoulins). Recent.
. . , Goelopleurus, Ag. (Fig. 372). Amb with two vertical

Eocene ; Biarritz. France. J/i. t i • • , i 11 i a ± i« i

1 rows of plain, primary tubercles placed on flat scrobicules,
diminishing in size toward the apex, and sometimes replaced there by granules.
lAmb with a large bare median area abactinally ; the tubercles largest at the

Fw. 371.

Cyphosoma Koenigi, Mantell. White Chalk ;
Sussex. Ventral aspect, Vi-

Fio. 372.
Coelopleurus equis,

232

ECHINODERMATA— ECHINOIDEA

SUB-BRANCH III

ambitus, sometimes disappearing toward the apical system. Tertiary and
Eecent.

Podocidaris, A. Ag. Eecent ; Caribbean Sea and Philippines.

Family 6. Temnopleuridae.

Test highly ornamented, tumid, or spheroidal. Ambulacra with triple compound
plates, united with the interambulacral plates by grooved and sometimes pitted sutures.
All plates of the test, except the component ambulacral plates, united by a dowelling of
knobs and sockets. Cretaceous to Recent.

Glyphocyphus, Haime. Test small, depressed spheroidal. Amb narrow,
straight, with two vertical rows of small, perforate, crenulate, primary
tubercles, and numerous miliaries. lAmb broad, with two rows of primaries
somewhat larger than those of the Amb. Transverse and median sutures
grooved. Cretaceous and Eocene.

Dictyopleurus, Duncan and Sladen. Eocene ; Asia and Europe. Egypt.
Paradoxechinus, Laube. Miocene ; Australia. Hchinocyphus, Cott., and Zeuglo-
pleurus, Gregory. Cretaceous ; Europe.

Temnopleurus, Ag. Transverse sutures of all plates grooved and pitted.
Apical system small, compact, slightly projecting. Tertiary and Recent.

Temnechinus, Forbes. Test small, subglobose, depressed abactinally. Both
areas with two vertical rows of plain primaries. Apical system prominent,
compact, the sutures between the plates more or less grooved. Late Tertiary
and Recent.

Salmacis, Ag. Eocene, Pliocene, and Recent. Microcyphus, Amblypneustes,
and Holopneustes, Ag. Recent.

Family 7. Echinometridae. Gray (emend. A. Agassiz).

Test large, either symmetrical and polyporous, or with the long axis not coinciding
with the antero-posterior axis, and the compound ambulacral plates with three or more
pairs of pores. Teeth keeled. Tertiary and Recent.

Heterocentrotus, Colobocentrotus, Brandt ; and Echinometra, Rondelet. Recent.
'es, Ag. (Heliocidaris, Desm.), (Fig. 373). Antero-posterior axis

forming an angle with
the major diameter. Amb
straight, with pores in
arcs of three pairs dor-
sally, crowded and tri-
serial below the ambitus.
Both areas with two
vertical rows of plain
tubercles, diminishing
actinally and dorsally.

FIG. 373.

Stomopneustes variolaris, Ag.
pound Amb plate.

Com-

FIG. 374.

yngylocentrotus
, Mull.

sp.

Droebach-
Compound

Stro
iensis,
Amb plate.

Tertiary and Recent.
Strongylocentrotus, Brandt (Fig. 374). Test symmetrical and polyporous.
Amb straight, broad at the ambitus and peristome, and with broad poriferous
zones. Pairs of pores in oblique arcs, or almost transverse series of from four
to ten pairs, and crowded actinally. Interporiferous areas with two vertical
rows of plain, imperforate primary tubercles ; secondaries and miliaries also

ORDER m EUECHINOIDEA— HOLECTYPOIDA 233

present. I Amb with two rows of primary, and four or more of secondary
tulu-rclcs. Late Tertiary and Recent.

Sphaerechinus, Desor. Amb straight, wide. Pairs of pores in arcs or
oblique lines of four to eight pairs, poly serial actinally. Interporiferous areas
with two to six vertical rows of plain, imperf orate primaries, and horizontal
rows of secondary tubercles and miliaries. I Amb with two to twelve vertical
rows of primaries. Pliocene and Recent.

Eurypneustes, Aeolopneustes, Duncan and Sladen. Eocene ; Asia.

Family 8. Echinidae. Wright.

Test symmetrical ; ambulacra and interambulacra of equal width. Ambulacral
plates compound, with three pairs of pores, which are arranged in high or low arcs of
triplets. Coronal plates without pits and grooves, and their opposed surfaces plain.
Teeth keeled. Cretaceous to Recent.

Echinus, Rond. Amb straight, with narrow poriferous zones ; pore pairs
in more or less vertical arcs of triplets. Interporiferous areas with two
vertical rows of small, plain, primary tubercles, with or without irregularly
placed secondary tubercles and primaries. lAmb with two vertical rows of
primaries, and few or numerous rows of secondary tubercles and miliaries.
Peristome small, circular ; the buccal membrane with ten buccal plates bearing
tentacles and small spines. Cretaceous to Recent.

Subgenus Psammechinus, Ag. Like Echinus, but the buccal membrane with numerous
concentric plates, besides the ten buccal plates. Cretaceous to Recent.

Stirechinus, Desor. Both areas with two rows of large, plain, primary
tubercles situated on raised keel-like projections. Pliocene ; Europe.

Glyptechinus, de Loriol. Cretaceous. Tripneustes, Ag. Miocene and Recent.

Leiopedina, Cott. (Chrysomelon, Laube). Test large, melon-shaped. Amb
long, straight, very broad. Poriferous zones broad, pairs of pores triserial,
and almost horizontal. Plates very numerous, low, broad, compound.
Tubercles small, plain, finely perforate, in two distant vertical rows. lAmb
broad, with two rows of tubercles similar to the ambulacral, and with inter-
mediate granules. Eocene.

Hypechinus, Desor. Tertiary. Toxopneustes, A. Ag. (non Ag.) Recent.
Boletia, Desor. Recent.

Order 3. HOLECTYPOIDA. Duncan.

" Euechinoidea with an actinal, central peristome, and the periproct situated be-
yond the dor so-central system in the posterior interambulacrum ; with external branchiae;
with a pair of pores or only one pore to an ambulacral plate ; with feeble jaws and
vertical teeth, or without these structures ; with a variably constructed perignathic
girdle. Spheridia present." — Duncan.

SECTION I. — Perignathic processes of the ambulacra present.
Holectypus, Desor (Fig. 375). Amb narrow, straight, widest at the am-
bitus; some of the plates compound. I Amb with rather large plates, and
many rows of tubercles. Peristome large, decagonal, with well -marked
branchial incisions, jaws, and feeble perignathic girdle. Periproct large,

234

ECHINODERMATA— ECHINOIDEA

SUB-BRANCH III

pyriform, situated between the peristome and posterior edge of the test.
Apical system small, central. Jura and Cretaceous.

Pileus, Desor. Test large, sub - hemispherical dorsally, flat actinally.

A, B, Holectypus oriftcatus, Schlot. Upper Jura ; Streitberg, Franconia. C, D, H. depressus, Leske sp.
Middle Jura ; France. Apical system and ventral surface (after (Jotteau).

Tubercles small, irregularly arranged. Periproct supra - marginal, small,

broadly ovoid. Upper Jura.

Pygaster, Ag. (Fig. 376). Test large, depressed dorsally, concave actinally.
Amb straight, similar, flush or slightly raised,
widest at the ambitus. Poriferous zones
straight, simple, narrow ; tubercles of interpor-
if erous areas in two or four vertical rows ; those
of the lAmb in horizontal rows. Peristome
large, decagonal, with jaws and feeble perignathic
girdle. Periproct immediately beyond the apical
system. Jura and Cretaceous.

SECTION II. — Perignathic girdle with well-
interambulacral ridges; ambulacral pro-
cesses rudimentary or absent.

Discoidea, Klein (Fig. 377). Test hemi-
spherical above the margin, flat actinally. Amb
narrow, with some compound plates near the
ambitus and actinally ; pairs of pores very
numerous, small. lAmb with distinct median
sutures, and small, perforate, and crenulate
tubercles. Plates within the actinal surface
Young individual, with radiating ribs, ten in all, extending as far
as the peristome; appearing on casts as deep
Periproct small, infra-marginal. Cretaceous.

FIG. 376.

Pygaster umbrella. Ag. Oxfordian ;
Chatillon-sur-Seine. '
1/1 (after Cotteau).

depressions.

Discoidea cylindrica, Ag. Upper Cretaceous; Liineburg. A, Side-view. B, Test broken open to show the
inner partitions, 1/1-

Conoclypeus, Ag. (Fig. 378). Test large, thick ; conical or vaulted dorsally,

235

ORDER iv EUECHINOIDEA— CLYPEASTROIDA

rather flat actinally. Amb long, open, with broad poriferous zones nearly to
ambitus, narrowing thence to peristome. Pores wide apart and in pairs where

Conodypeus conoideus, Goldf. sp.

FIG. 378.
Eocene ; Kressenberg, Bavaria (2/3 natural size).

the zones are broad ; the pairs separated by costae. Pores continued in single
series over the ambitus as far as the central, pentagonal peristome. Periproct
infra-marginal, oval (?). Cretaceous ; Eocene.

Galeropygus, Cotteau ; Pachyclypeus, Desor. Upper Jura ; Europe.

Order 4. CLYPEASTROIDA. Duncan.

" Euechinoidea with an actinal peristome, a periproct situated beyond the dor so-
central system, in the posterior interambulacrum ; with external branchiae; with
tentacular pores in the interambulacra, and more than a pair to an ambulacral
plate; tentacles heteropodous in arrangement; with more or less horizontal and
rarely vertical teeth, and with jaws situated superiorly to the disconnected perignathic
girdle. Spheridia few, covered." — Duncan.

Family 1. Fibulariidae. Gray (emend. Duncan).

Test small, with rudimentary, widely open, few-pored petals. Interambulacra
small, with a single apical and a single peristomial plate. Ambulacra limited
actinally on the interior of the test by low vertical partitions at ibtir sides, radiating
toward the peristome. Perignathic processes broad, low, one • on each interambu-
lacrum. Periproct usually actinal. Cretaceous to Kecent.

Echinocyamus, van Phels. Test thick, depressed, pyriform or sub-circular
in outline, concave actinally. Amb broader than the lAmb, short where
slightly petaloid, widely open distally ; pairs of pores few and increasingly

236

ECHINODERMATA— ECHINOIDEA

SUB-BRANCH III

Pliocene ; Sicily

far apart. Peristome central, pentagonal, with small jaws. Periproct be-
tween the peristome and posterior edge of the test.
Cretaceous to Recent.

Sub-genus. — Scutellina, Ag. Periproct small, marginal, or
more or less supra- or infra-marginal. Tertiary.

Sismondia, Desor. Test sub-pentagonal or ovoid,
depressed, inflated at the margin. Petaloid parts of
the Amb usually long, more or less open ; pairs of
pores not continued actinally. Tubercles minute.
Eocene and Miocene.

Fibularia, Lam. (Fig. 380). Test thin, ovoid, tumid
dorsally and at the side. Amb short ; pairs of pores
FlG- 3SO very few, continued wide apart to the margin, non-

siibgidbosa, Goidf. conjugated. Peristome and periproct small, sunken,.
Mae" close togetner- uPPer Cretaceous and Recent.
Euna, Ag. Tertiary ; Europe.

Family 2. Clypeastridae. Agassiz.

Test small to very large, depressed, flat, or high. Petaloid parts of the ambulacra
highly developed, usually unequal ; the actinal furrows straight. Interambulacra
actinally discontinuous; one peristomial and two apical plates in each. Peri-
gnathic processes tall, narrow, two on each ambu-
lacrum, fitting in below the large jaws. Peristome
central, pentagonal ; periproct small, marginal
or infra - marginal. Internal structure with
needles, pillars, and other processes extending
from floor to roof, especially near the edge of the
test ; sometimes these are
fused to form concentric
partitions, and the ambu-
lacra may also be protected
by an inner wall. Tertiary
and Recent.

FIG. 381.

Clypeaster Aegypticus, Mich. Pliocene ; Gizeh, near Cairo. Fragment
howing internal calcareous deposits, aw, Auricles.

ter, Lam. (Figs.
381,382). Actinal surface
flat, with the peristome
suddenly deeply sunken;
edge thin, undulating in
contour, with or without
re-entering angles. Petals
long, broad, tumid ; pores wide apart, unequal, conjugated. Periproct near
or at the edge. Internal structure not forming a double wall covering the
Amb. Tertiary and Recent.

This genus includes 3ome of the largest Sea-urchins known. Recent species are littoral,
or shallow water inhabitants.

Diplothecanthus, Duncan (Echinanthus, Breyn. p.p.) Margin and actinal
surface tumid, but hollow from the margin to a deep central peristome. In-

ORDER IV

EUECHINOIDEA— CLYPEASTROIDA

237

tcrnal structure investing the Amb with a double wall, but not forming con-
centric partitions near the edge. Tertiary and Recent.

FIG. 382.
Clypeaster grandiflorus, Bronn. Miocene ; Boutonnet, near Montpellier. 1/2 natural size (after Desor).

Plesianthus, Duncan ; Anomalanthus, Bell. Recent.

Laganwn, Klein. Belongs properly to a separate family or sub-family.
Tertiary and Recent.

Family 3. Scutellidae. Agassiz.

Test very fiat, with entire or incised margin ; lunules or slits in the areas or
not. Ambulacral furrows bifurcating and branching. Peristome flush ; jaws flat,
teeth superior. Radiating partitions between the floors internally. Tertiary and
Recent.

Scutella, Lam. (Fig. 383). Test circular or sub-circular in outline, some-
times undulating or notched, broadest behind. Petaloid parts of the Amb
unequal, well-developed, nearly closed. Peristome small, central, sub-circular.
Periproct very small, infra-marginal. Apical system central, more or less
pentagonal. Tertiary.

Sub-genus. — Echinarachnius, Leske (Lendraster, Ag.) Apical system eccentric in front
or behind. Periproct actinal, marginal or supra-marginal. Recent.

Echinodiscus, Breyn. (Amphiope, Lobophora, Ag.) Like Scutella, but trun-
cated posteriorly, and with two round or elongate lunules or slits there,
one in each of the median lines of the postero-lateral Amb. Tertiary and
Recent.

Encope, Ag. Test with a broad notch or a lunule in the median line of
each Amb, and a lunule in the posterior lAmb. Miocene and Recent.

Mellita, Klein. Test very flat, with five or six usually closed lunules,

238

ECHINODEKMATA— ECHINOIDEA SUB-BRANCH in

more rarely cuts ; one in the median line of the posterior lAmb, the others

c

FIG. 383.
Scutella subrotundata, Lain. Miocene ; Bordeaux. A, B, Ventral and dorsal aspects. C, Section, Vi-

in the Amb. Amb petaloid dorsally, the posterior pair the longest. Pliocene
and Eecent.

Lenita, Desor. Eocene. Eotula, Klein. Eecent. Arachnoides, Breyn.
(Asterodaspis, Conrad). Pliocene and Recent.

Order 5. SPATANGOIDA. Duncan.

" Euechinoidea with an adinal or a frontal peristome, and a periprod situated
the dorso-central system, in the posterior interambulacrum ; without external
branchiae ; jaws, teeth, and perignathic girdle. Spheridia numerous." — Duncan.

Sub-Order A. CASSIDULOIDEA. Duncan.

Ambulacra abactinally simple, petaloid or sub-petaloid, usually similar. Some
or all of the interambulacra with a single peristomial plate ; the postero-lateral areas
symmetrical actinally, without any fusion of plates; no plastrons. Peristome
I, with or without floscelles.

Family 1. Echinoneidae. Wright.

Test tall, or low and tumid dorsally ; tumid and rarely flat actinally. Apical
system central, compact, with four perforated basals. Ambulacra similar, dorsally
apetalous or sub-petaloid. Pores in simple pairs or in oblique triplets actinally ; no
floscelle. Peristome oblique or transversely elliptical, rarely symmetrical. Periproct
actinal, marginal or supra-marginal. Cretaceous to Recent.

ORDER v EUECHINOIDEA— SPATANGOIDA 239

Sub-Family A. ECHINOCONINAE. Duncan.

Tall, conical, or sub-hemispherical tests, rather flat actinally. Ambulacra with
pairs of pores in oblique triplets actinally.

Echinoconus, Breyn. (Galerites, Lam.) Amb flush or slightly raised, apetal-
ous, straight ; some of the plates compound. Peristome sunken, slightly
decagonal, symmetrical. Perignathic girdle indicated by a thickening of the
I Amb as a low falx- i id^e. Abundant in the Lower and Middle Cretaceous.

Lanieria, Duncan. Cretaceous or Eocene ; Cuba.

Sub-Family B. ECHINONEINAE. Desor.

Test low, tumid, and more or less pulmnate actinally ; peristome central or sub-

<->'i<1ral diul oblique.

Echinoneus, van Phels. Amb narrow, actinally unequally broad, owing to
obliquity of the large, triangular peristome. Miocene to Recent.
Caratomus, Ag. Cretaceous. Amblypygus, Ag. Tertiary.
Pygaulus, Ag. (Fig. 384). Test small, thick ; apical system slightly

FIG 385.

Ag. Urgonian I'/irina incisa, Ag. sp. Neocoinian (Hils) ; Berklingen,

(Schrattenkalk);Santis, Switzerland. 1/1- Brunswick. 1/1-

eccentric in front. Amb narrow, widest at the ambitus ; pairs of pores in simple
series, conjugated; the pores of a pair sometimes differently shaped. Cre-
taceous.

Pyrinu, Desm. (Fig. 385). Like the preceding, but pores non-conjugated,
and the pairs separated by costae. Cretaceous and Eocene.

Anorthopygus, Cotteau. Cretaceous (Cenomanian) ; Europe.

Sub-Family C. ECHINOBRISSINAE. Duncan.

Test depressed, elongate, tumid. Ambulacra sub-petaloid. Apical system and
peristome eccentric; floscelle absent or rudimentary. Interambulacra entering the
peristomial margin with a single plate. Periproct supra-marginal.

Echinobrissus, Breyn. (Nudeolites, Lam.), (Fig. 386). Test ovate, rounded in
front, broadest and more or less truncated behind ; or rectangular, with the
angles rounded ; or sub-circular ; concave actinally. Amb unequal, open at the
end of the sub-petaloid parts ; pairs of pores in simple series, more or less
unequal in shape and size, the outer ones elongate; below the sub-petaloid
parts the pores are in small oblique pairs, conjugate or riot. Periproct at

240

ECHINODERMATA— ECHINOIDEA

SUB-BRANCH III

upper end of a groove situated on the abactinal area of the test. Abundant in
Upper Jura and Cretaceous ; present also in Eocene and late Tertiary.

FIG. 386.

A. B, Echinobrissus clunicularis, Llhwyd sp. Cornbrash ; Egg, Aa
j>per Oxford!
(after Cottean).

. 1 sp. Cornbrash ; Egg, Aargau. l/i« C, D, E. scutatus, Lam. sp.
Upper Oxfordiau ; Trouville, Calvados. C, Ventral aspect of large individual. D, Apical system, enlarged

Sub-genus Dochmostoma, Duncan (Trematopygus, d'Orb.) Like the preceding, but with
oblique peristome. Cretaceous.

£otriopygus, d'Orb. Cretaceous. Ilariona, Dames. Eocene.

Family 2. Cassidulidae. Agassiz.

Test variable in shape. Ambulacra petaloid, sub-petaloid, or apetalous dorsally,
and with crowded doubling of the pairs of pores close to the peristomial margin,
forming with the single, swollen, and ornamented interambulacral peristomial plates
a floscelle. Jura to Kecent.

Cassidulus, Lam. (Fig. 387). Test small, oblong, depressed, convex
dorsally, flat actinally. Amb short, sub-petaloid, not closing ; pores continued

from the middle part to the well-
developed floscelle. Peristome
eccentric in front ; periproct supra-
marginal, longitudinally elongated.
Cretaceous and Eocene.

Sub - genus Rhynchopygus, d'Orb.
Periproct transversely elongate, with over-
hanging rostrum. Cretaceous to Recent.

Sub -genus Pygorhynchus, Ag. Test
concave actinally, with long petals. Peri-

FlG- 387- stome and periproct longest transversely.

i lapis-cancri, Lam. A, Test in three positions. Cretaceous to Miocene.
-C, Floscelle, enlarged.

Echinanthus, Breyn. Test thin,

ovoid, low, convex dorsally, and concave actinally. Amb unequal, petaloid,
usually short. Peristome eccentric in front, with well-developed pentagonal
floscelle. Periproct oval, marginal or supra-marginal, at the top of a longi-
tudinal groove. Upper Cretaceous and Eocene.

Stigmatopygus, d'Orb. Cretaceous. Eurhodia, d'Arch. and Haime. Eocene.
Paralampas and Neocatopygus, Duncan and Sladen. Eocene. Catopygus, Ag.

OIlDKll V

EUECHINOIDEA— SPATAXGOIDA

Cretaceous. Studeria, Duncan. Tertiary and Recent. Phyllobrissus, Cotteau.
Jura and Cretaceous.

Cltf/H'Hx, Klein. Test large, low, nearly flat actinally. Ami wide, prtaloiM,
not closing dm-sally, narrow at the ambitus and actinally. Pairs of pores in

' imms, Cott. Kiniiiieridgian ; Toniijt-sltcrj:, near H.-iimvcr. .1, /;, Dorsal and ventral

trsi, f/4 natural size. C, Apical system, enlarged. /), Ainbulacral plate, magnified.

the petaloid parts with the inner pore small and circular, the outer transversely
elongate, and in a long groove. Periproct high up, usually in a groove along
the median line of the posterior lAmb. Upper Jura.

PyguruSj Ag. (Fig. 388). Test large, angular, rounded, or cordiform in
marginal contour; depressed or rather tall and sub -conical dorsally. Amb

Echinolampns Kleini, Goldf.

Oligocene ; Doberg, near Biinde.

flush dorsally, unequal, long ; the petaloid parts contracting but not closing
marginally, and expanding again actinally, where the Amb are grooved. Peri-
proct infra-marginal, pyriform or ovoid, in a special area or rostrum close to
the posterior edge of the test. Upper Jura and Cretaceous.

Echinolampas, Gray (Fig. 389). Test variable in size and shape, more or
less ovoid or circular at the tumid marginal outline ; tall and conical or
VOL. i n

242

ECHINODERMATA— ECHINOIDEA

SUB-BRANCH III

depressed dorsally. Amb petaloid for a variable distance ; pores of the petals
differing in shape, conjugated, and continued beyond in simple series. Peri-
stome slightly in front, or sometimes central. Periproct transversely elliptical,
infra-marginal. Widespread in Tertiary and Recent.

Conolampas, Neolampas, A. Ag. Recent. Plesiolampas, Duncan and Sladen.
Eocene. Palaeolampas, Bell. Upper Cretaceous and Tertiary.

Family 3. Collyritidae. ' d'Orbigny. (Dysasterinac, Gray.)

Apical system disconnected, either elongate or sub-compact. Ambulacra similar ;

bivium widely separated from the trivium;
floscelle absent. Jura to Recent.

Collyrites, Desm. (Fig. 390). Test
ovoid, tumid, more or less truncated
posteriorly. Amb disjunct, the an-
terior one sometimes in a slight
groove. Width of the Amb increas-
ing toward the ambitus ; pairs of pores
in low primary plates. Periproct
posterior, supra -marginal, placed in
a groove. Apical system elongate,
separated by numerous small plates
belonging to the postero-lateral lAmb.
Very abundant in the Middle and
Upper Jura and Cretaceous.

Dysaster, Ag. Differs from Colly-
rites in details of the apical system,
the basals not being separated by the
antero- lateral radial plates. Upper
Jura and Lower Cretaceous.

Hyboclypeus, Agassiz. Jura. In
c, borso- fraclypeus, Gauthier. Upper Cre-
taceous. Grasia, Mich. Jura.

FIG. 390.

Collyriteselliptica,Desm. Callovian; Mamers, Sarth
A, B, Test in profile and from above, 1/1-
central system, enlarged.

Metaporhinus, Mich. Test very tall, slightly longer than broad, sub-cordi-

Fio. 391.

Hyboclypeus giVbendus, Ag. Middle Jura ; Soleure, Switzerland. A, B, Dorsal and ventral views. C, Profile.
D, Apical system, enlarged.

form, projecting upwards anteriorly, grooved and oblique behind. Anterior

«>KI»KU V

EUECHINOIDEA— SPATAXGOIDEA

•i I :>,

.////./' in ;i groove, with small, simple, distant pairs of pores; the other Amb
flexuous, with comma-shaped pores placed obliquely to one another. Periproct
supra-marginal. Upper Jura and Lower Cretaceous.

Sub Order B. SPATANGOIDEA. Duncan.

J't ristome ecmitrii' in //•»///, rarely pentagonal in flu- mlulf, usimlli/ with a
t rim- liilirinn, h-kiml u'hirh is a long plastron loini</»/ /////•/>///// /»// the posterior
Jtiiiiitliti-i-ii ilitxiniiliir. Interambulacra with a single plate nl tin'

l >• ri*f initial margin; the postero -lateral areas usually unsymmetrical //'•///«/////.

Fascioles present or «/«•> ///.

Family 1. Ananchytidae. Desor.

Test ovoid "/• tvb-cordiform in marginal outline, tall or depressed, and with large
/Jut'*. Ambulacra in a bivium and trivium, nearly similar, flush, apetalous ; pairs
of pores largest near the apex and at the peristome, may be uniporous. Periproct
nii-iiiUi- in jHMititnt. Cretaceous to Recent.

/:'<•///// 'H-nri/x, Breyn. (Ananchi/tes, Mercati), (Fig. 392). Test large, oval in
marginal outline; high, rounded, or keeled apically, flat actinally. Amb
biporous, the pairs of pores well
• k-vi'loped abactinally, but becom-
ing smaller, closer, and oblique
toward the ambitus, where they
are more distant. Posterior Amb
actinally long and broad, the pairs
small, and pores oblique. Peri-
stome oval, broader than long.
Periproct infra - marginal, pos-
terior, oval. Apical system elon-
gate. Very abundant in the
Upper Cretaceous. E. ovata,
Leske sp., often attains a very
large size.

/In! aster, Ag. (Fig. 393). Test
ovoid in marginal outline, flat
actinally, tumid and high abactin-
ally. Anterior Amb in a shallow
groove. Peristome elliptical,
broadest transversely. Periproct
supra - marginal, oval. A] »i « -. 1 1
system elongate. Cretaceous and
Miocene.

0/aster, DeSOr. Test Small, Echtnooory, ovata, Leske sp. Wliitc chalk ; HaWcm, West-

tumid. Anterior Amb sometimes phajia- ; B> P™&1* a"d \eutral view> Vs . c, Do«o^ent»i

system, enlarged. D, Portion of Amb and I Amb areas. 1/1-

in a shallow groove. Peristome

oval, broadest transversely. Periproct supra -marginal, circular or ovoid.

Apical system elongate. Cretaceous. 0. pilula, Ag. sp.

Hemipneustes, Ag. Test large, ovoid in marginal outline, high and tumid
dorsally, flat actinally. Anterior Amb in a deep, narrow groove extending to

FIG. 392.

244

ECHINODERMATA— ECHINOIDEA

SUB-BRANCH III

the elongate apical system, its pairs of pores numerous and small, the rows
wide apart. Paired Amb more or less curved, open distally, with dissimilar

PIG.

A, B, Holaster subglobosus, Ag. Cenomanian ; Rouen. 1/1-
enlarged.

, H. suborliculuris, Defr. Dorso-central system,

pores. Peristome much sunken, crescent -shaped, broad. Periproct supra-
marginal. Upper Cretaceous. H. radiatus, Lam. sp.

Cardiaster, Forbes (Stegaster, Pomel, p.p.) Similar to Holaster, but anterior
groove deeper and with angular margin. Periproct oval, placed in a depression
in the truncated posterior face. A more or less complete marginal fascicle
passing below the periproct. Cretaceous.

Sub-genus Jnfulaster, Hagw. Test high in front, narrow ; anterior groove deep and with
strong lateral keels. Fascicle absent. Upper Cretaceous.

Hagenowia, Duncan (Cardiaster, Forbes, p.p. ; Stegaster, Pomel, p.p.)
Upper Cretaceous.

Urechinus, Cystechinus, A. Ag. Late Tertiary and Eecent. Calymne,
Wyv. Thorns. Recent. Enichaster, de Loriol. Oligocene. All with uni-
porous Amb.

Stenonia, Desor. Like Echinocorys (Ananchytes), except that the apical
system is compact, and the Amb equal. The solitary species, S. tuberculata,
Defr. sp., is abundant in the Upper Cretaceous (Scaglia) of the Southern Alps
and the Apennines.

Family 2. Spatangidae. Wright.

Test ovoid or cordiform, longer than broad, with numerous plates, and usually
with an anterior groove. Ambulacra in a bivium and trivium, the anterior differing
from the others in shape and construction. Pairs of pores of the petaloid parts
differing from the others. Fascioles present or absent. Cretaceous to Recent.

SECTION A. ADETES. All fascioles absent.

Isaster, Desor. Petals not closed. Peristome large, with a posterior
labrum. Cretaceous.

Epiaster, d'Orb. (Macraster, Roemer.) Anterior Amb in a groove ; paired

ORDER V

EUECHINOIDEA— SPATANGOIDEA

245

Ami petaloid dorsally, with elongate, unequal pores. lAmb tumid dorsally.
Peristome transverse, tumid in front, and usually with projecting labrum.
Periproct longitudinal, supra-
marginal. Cretaceous.

ri 1 • Tt / rn

EchMospatagw, Breyn. (Tox-
aster, Ag. p.p.) Anterior Anib
in a broad shallow groove, with
unequal pairs of pores. Paired
A ml sub-petaloid, flexuous, with
unequal poriferous zones and un-
equal pairs of pores. Peristome
transverse, sub-circular, or penta-
gonal. Tubercles small, per-
forate, and crenulate. Abundant
in Lower and Middle Cretaceous.

k'ltit'iltiafrr, d'Orb. (Heteraster,
d'Orb.) Petaloid parts of antero-lateral Amb divergent, flexuous, tending to
close, and with very unequal poriferous zones, of which the posterior are the
' ; pairs of pores oblique. Postero - lateral Amb short, divergent.
IVristome labiate, wide, arched in front. Periproct in posterior truncation.
Cretaceous.

H'-mipatagus, Desor (Fig. 395). Test small, cordiform. Anterior Amb
with small pores in a shallow furrow. Paired Amb long, petaloid, nearly

Pro. 395. w/r

Hemipatagw Hofmannl, Goldf. Oligo- \V

e; Doberg, near Biinde. A, Dorsal
\v. /;, I'ruiile. C, Ventral aspect, 1/1
(after Goldfuss). ^^••^^"^

flush. The lateral I Amb with a few large perforate and crenulate tubercles
in deep scrobicules. Periproct supra-marginal. Tertiary.

Platybrissus, Grube. Recent. Palaeopneustes, A. Ag. Recent, and perhaps
Eocene.

SECTION B. PRYMNADETES. Subanal fascicle absent, other fascicles present.

Hemiaster, Desor (Fig. 396). Anterior Amb in a shallow groove, the
pores oblique, and in pairs on either side. Antero-lateral Amb petaloid
dorsally, sunken, diverging, and much longer than the postero-lateral. Pores
of the petaloid parts conjugated, the outer ones usually the largest. Peri-
petalous fasciole present.

Sub-genus Tripylus, Phill. (Abatus, Troschel). Recent.

246 ECHINODERMATA— ECHINOIDEA SUB-BRANCH in

Faorina, Gray. Recent. Pericosmus, Ag. Cretaceous and Tertiary.

FIG.

Hemiaster Orbignyanus, Desor. Upper Cretaceous ; Martigues,. Provence (after d'Orbigny). A-C, Ventral,
dorsal and side views of test, 1/1- A Pores of the odd Amb. E, Pores of the paired Amb, enlarged.

Linthia, Merian (Desoria, Gray), (Fig. 397). Anterior Amb in a deep

FIG. 397.
Linthia Heberti, Cotteau. Eocene ; Lonigo, near Vicenza. 8/4 natural size (after Dames).

groove, the pores round and small, in pairs on either side. Antero-lateral
Amb longer and more divergent than the others, with
petals sunk in grooves. Pores conjugated. A peripetalous
and lateral fasciole present. Cretaceous to Recent.

Schizaster, Ag. (Figs. 398, 399). Resembling Linthia,
but the apical system posteriorly eccentric, and the

Amb very diverse. Tertiary
and Recent.

Prenaster, Desor; Orni-
thaster, Coraster, Cotteau.
Eocene.

Agassizia, Val. ; Moira,
A. Ag. Tertiary and Recent.
Moiropsis, A. Ag. Recent.

FIG. 398.

Schizaster Archiaci, Cott.
Eocene ; San Giovanni Ilari-
one, near Vicenza.

FIG. 399.

SECTION C. PRYMNODESMIA.

Schizaster fragilis, Ag. Apical SubdUCtl fasciole present.

system, greatly enlarged
Loven).

Ap
(a

Micraster, Ag. (Figs. 400,
401). Test cordiform, tumid, rather depressed. Anterior Amb apetaloid, in
a shallow depression ; antero- lateral Amb sub-petaloid dorsally, diverging ;

ORDER V

EUECHINOIDEA— SPATANGOIDEA

247

postero-lateral shorter than the others, with elongate, conjugated pores.
Periproct supra-marginal ; apical system eccentric in front.
Broad subanal fasciole. Abundant in Middle and Upper
Cretaceous ; less common in Eocene and Miocene.

/;/ V'.SSMS, Klein (Brissomorpha, Laube) ; Meoma, Gray ;
Metalia, Gray. Tertiary and Recent. lihinobrissus, A. Ag.
Recent.

Brissopsis, Ag. (Deakia, Pavay), (Fig. 402). Ami
unr<|ual, bare and large near the peristome. Anterior
.linl slightly sunken, with small pairs of close pores. Flo m

Paired .////// sunken, the antero-lateral pair sub -petaloid,
equal to or larger than the postero-lateral, straight or L
curved. A subanal and peripetalous fasciole. Tertiary and Recent.
Sub-genus Cyclastcr, Cotteau. Antero-lateral ^i&jlivergent. Eocene.

Brissopatagus, Cotteau. Allied to Brissopsis. Eocene.

Spatiiii;tnti, Klein. Anterior Anil in a broad, deep groove, with distant

Fio. 401.
, Goldf. White Chalk ; Meudon, near Paris. Natural size.

pairs of small pores. Paired Ami petaloid, with broad, sunken poriferous
zones. Periproct large, supra-marginal, transverse. lAml
with large crenulate and perforate primary tubercles, and
fine granulation. Subanal fasciole only. Tertiary and
Recent.

Maretia, Gray. Tertiary and Recent.

Eupatagus, Ag. Anterior Ami in a shallow, abactinal
depression, narrow, and with small, distant pairs of pores.
The paired Ami petaloid dorsally, long, wide, closed ; por-
iferous zones broad, more or less sunken ; pores dissimilar.
lyrifera, Peripetalous and subanal fasciole. Tertiary and recent.

rnla^ed (alSrLovenr"' Sub-genus Macropneustes, Ag. (Peripneustes, Cott.), (Fig. 402 bis).
Test large, thick, cordiform. Petals elongate or broad, grooved or

semi -Hush, open or imperfectly closed. Poriferous zones of equal width with the inter-
poriferous. Eocene and Recent.

Gualtieria, Desor. Eocene. Echinocardium, Gray ; Breynia, Desor ; Lovenia,
Ag. and Desor. Tertiary and Recent.
I

248

ECHINODERMATA— ECHINOZOA

SUB-BRANCH III

SECTION D. APETALA.

Ambulacra flush, apetalous, generally uniporous, and either similar or diverse ;
plates high, few, often hexagonal. Fascioles usually present.

Under this head are included the following recent genera, all but the first

two of which have fascicles :
— Genicopatagus, Palaeobrissus,
A. Ag. ; Aceste, Wyv. Thom-
son ; Aerope, Norman ; Pdlaeo-
tropus, Lov6n ; Homolampas,
Argopatagus, A. Ag. ; and
Cleistechinus, de Loriol.
Miocene.

Family 3. Leskiidae. Gray.

Test thin, ovoid. Apical
system with three basal plates
fused into one. Peristome
eccentric in front, pentagonal,
with five angular buccal plates.

Palaeostoma, Lov6n
(Leskia, Gray). Eecent ;
China, East Indian Islands.

Family 4. Pourtalesiidae.

Loven.

Test very elongate, sub-
cylindrical or obconical, truncated
anteriorly, fiat actinally. Peri-
stome in a deep anterior recess ;
periproct actinal, or above the
projecting posterior rostrum
when such is present. Ambu-
lacra flush, apetalous, sometimes
discontinuous; pores single or
slit-like.

Eecent.

Mdcropneustes MenegMnii, Desor.
Vicenza.

FIG. 402 bis.

Eocene ; Monte Spiado, near

Pourtalesia, Spatagocystis, Echinocrepis, A. Ag.

Range and Distribution of the Echinoidea.

Fossil Sea-Urchins make their appearance as early as the Ordovician, but
are represented very sparsely by forms differing in a marked degree from the
normal (Bothrioddaris, Echinocystites). The order Perischoechinoida, character-
ised by its supernumerary columns of plates, is widely, but by no means
numerously, distributed in the Devonian and Carboniferous of North America
and Europe.

Fragmentary remains of true Cidarids are found in the Permian, perhaps

CLAM II

HOLOTHURIOIDEA 249

even in the Carboniferous (Eocidaris), but not until the Mesozoic era do the
Km.-hiiiuiilr.i completely replace the Palwechinoidea, which become extinct with
the Triassic Ti<ir<> 7/ inns.

All of the Triassic Euechinoidea are true Cidarids, and occur chiefly in the
Alps. Some of them are remarkable for their massive spines, which are found
in places, as at St. Cassian, very profusely ; perfect tests, however, are rare.
The European Lias yields a few Cidarids, and also the oldest known exocyclic
Urchins (f/.//ov,/'//.'/"-s /'wider).

Especially rich in regular Sea-Urchins, as well as in members of the
J-:,-liinnnn,laey Cassidulidae, and Collyritidae are the Middle and Upper Jura of
England, France, Germany, Switzerland, the Alps, and Northern Africa. The
Lower Cretaceous of the same region exhibits no essential change in the
Echinoid fauna; but the advent of large numbers of the Ananchytidae and
tfj><if,in,tiil,n>. in the Middle and Upper Cretaceous of Europe, Northern Africa,
Asia, and North America imparts to these horizons a characteristic appearance.

During the Tertiary the Cidaridae notably decline, the Echinoconinae
become entirely extinct, and the Clypeastroids and Spatangoids advance con-
spicuously into the foreground, taking on more and more the semblance of
recent species. Tertiary Sea-Urchins are distributed over the whole world,
and <ire particularly plentiful in the Nummulitic Limestone of Europe,
Northern Africa, Asia Minor, and India.

As to phylogenetic relationships, the Perischoechinoida may very properly
be regarded as the forerunners and ancestors of the regular Euechinoidea.
Among the latter the Cidaridae form the most primitive and stable type ;
the Diadematoida, on the other hand, exhibit a much greater aptitude for
variation.

Whether the irregular Euechinoidea are to be regarded as derived from the
Silurian Echinocystites, or from the regular Euechinoidea, is an open question.
It is obvious, however, that the gnathostomous Echinoconidae are in a number
of respects very closely related to the Regulares. The atrophy of teeth in the
Echinoneidae certainly gave rise to the Cassidulidae, and subsequent modi-
fications led to the derivation of the Ananchytidae and Spatangidae. The
Clypeastroids may also be looked upon with much plausibility as a peculiarly
modified offshoot of the Echinoconinae, and also as having affinities with the
Holectypoid genus Discoidea. The parallelism between ontogeny and phylo-
geny as manifested in various groups of the Echinoidea is very striking.

Class 2. HOLOTHURIOIDEA. Forbes.

The Holothurians, or Sea-Cucumbers, differ markedly from all other
Echinoderms, being characterised by the possession of an elongated, vermi-
form body, a terminal anus, and contractile tentacles surrounding the mouth,
and by the absence of a test proper.

Their palaeontological importance is small, since the only structures they
possess which are at all capable of preservation are the small integumentary
calcifications, occurring in the form of wheels, spicules, spherules, anchors,
etc. Such detached calcareous structures are known from the British Carbon-
iferous rocks, from the Lias and Dogger of Lorraine, the Upper Jura of
Franconia, and the Cretaceous of Bohemia ; they are unquestionably of Holo-

250

ECHINODERMATA— ECHINOZOA

SUB-BRANCH III

thurian origin, but as a rule are incapable of more precise determination.
On the other hand, however, Schlumberger has described a number of minute
calcareous bodies from the Calcaire Grossier (Eocene) of Paris, which seem
very certainly referable to the genera Synapta, Chirodotc^ and Myriotrochus.

TABLE SHOWING THE VERTICAL EANGE OF THE ECHINOIDEA.

Families.

Ordovician.

Silurian.

Devonian.

1

1

Permian.

i

H

e

1-9

i

0

Tertiary.

j

I. False echinoidea
Order 1. Cystocidaroida
,, 2. Bothriocidaroida
,, 3. Pcrischoechinoida

II. Euechinoidea
Order 1. Gidaroida
1. Cidaridae

Order 2. Diadematoida
1. Echinothuridae
2. Saleniidae

...'..

—

—

—

3. Hemicidaridae
4. Diadematidae
5. Cyphosomatidae

—

— -

— •

6. Arbaciidae

:

7. Temnopleuridae
8. Echinometridae

—

— >

9. Echinidae

,, 4. Clypeastroida
1 Fibulariidae

2 Clypeastridae

*

3. Scutellidae

Order 5. Spatangoida
1. Echinoneidae

2. Cassidulidae
3 Collyritidae

—

—

• —

4 Anancliytidae

5 Spatangidae

6. Leskiidae

!

—

Sub-Kingdom IV. VERMES. Worms.1

I!/l<it< rail// symmetrical animals with unsegmented or uniformly segmented, and
elongated, bodies. Segmented lateral appendages wanting. A dermal
muscular system and paired excretory canals (water-vascular system) present.

Of all the larger divisions of the animal kingdom, none is so poorly
adapted for preservation in the fossil state as the Worms, whose bodies, as a
rule, are totally without hard parts.

All Worms are laterally symmetrical, and in every case a dorsal and
ventral surface is distinguishable. The group of unsegmented Worms (Vermes
proper, as restricted by some authors) have either flat or cylindrical bodies,
and are accordingly distinguished as Plaf-yhelminthes or Flat Worms, and Nema-
thelminthes or Round Worms. But with the exception of a few rare parasitic
forms discovered in Carboniferous insects, or in insects enclosed in amber,
neither of these classes is represented in the fossil state.

The segmented Worms, or Annelida, are characterised by a division of the
body into metameres, which, although primitively alike, do not always remain
homonomous. They have a brain, a circumoesophageal ring, a ventral chain of
ganglia, and a vascular system. The body is more or less elongated, and
sometimes flattened, sometimes cylindrical. According as the internal
segments correspond exactly with the external, or as each internal segment
corresponds to a definite number (3, 4, or 5) of the external rings, two

1 Literature :
Pander, C. H., Monographic der fossileu Fisclie <k's silnrischen Systems cles russisch-baltischen

Gouveruemeuts, 1851.

Ehlers, E., Die Borstenwiirrner (Annelida Chaetopoda). Leipzic, 1864-68.
Ehlers, E., Ueber fossik- Warmer aus dem lithographischeu Schiefer in Bayeru (Palaeontographica,

Bd. XVII.), 1868.

Claparede, E., Recherches sur la structure des Annelides scklentaires, 1873.
Neivberry, J. S., Palaeontology of Ohio, vol. II. part 2, 1875.
Hinde, G'. J., On Conodonts from the Chazy and Cincinnati Groups ; and on Annelid Jaws from the

Cambro-SiluriftD, Silurian, and Devonian Formations in Canada, and from the Lower Carbon-
iferous in Scotland (Quar. Journ. Geol. Soc., vol. XXXV.), 1879.
Hinde, G. J., On Annelid Jaws from the Weulock and Ludlow Formations of the West of England

(Quar. Journ. Geol. Soc., vol. XXXVI.), 1880.

Etheridge, R., jun., British Carboniferous Tubicolar Annelides (Geol. Mag.), 1880.
Nathorst, A. G., On the Tracks of some Invertebrate Animals and their Palaeontological Significance

(K. Svensk. Vetensk. Akad. Handl., Bd. XVIII., XXL), 1881-86.
Hinde, G. J., On Annelid Remains from the Silurian Strata of the Isle of Gotland (Bihang till K.

Svensk. Vetensk. Akad. Handl., Bd. VII.), 1882.
Zittel, K. A., and Rohon. J. V., Ueber Conodonten (Sitzungsber. Bay. Akad. Wissensch., Bd. XVI.),

1886.
Clarke, J. J/., Annelid Teeth from the Lower Portion of the Hamilton Group, New York (Sixth

Annual Report State Geologist, 1886).

252

VERMES

SUB-KINGDOM IV

sub-classes are distinguished, Chaetopoda and Hirudinea. A further difference
is to be noticed in the locomotive organs, the Chaetopoda having bristle-bearing,
unjointed appendages (parapodia) on each ring of the body ; and the Hirudinea
having a terminal sucker. The latter group includes only the Leeches, which
are not known with certainty in the fossil state.

It is only the one order of marine Worms (Polychaeta) belonging to the
sub-class Chaetopoda with which the palaeontologist is practically concerned ;
as the Earthworms arid their allies (Oligochaeta) are wholly unknown as fossils.
The marine Chaetopoda are divisible into two principal sections, known as the
Sedentary or Tubicolous Worms, and the Nereid or Errant Annelides.

Sub-Order A. TUBICOLA. (Sedentaria.)

Annelides with indistinctly separated head, and short, usually
non - protrusible proboscis, without jaws. Parapodia short, and never used for

FIG. 403.

A, Serpula Umax, Goldf. Middle Jura ; Franconia. B, C, S. gordialis, Schloth. Upper Cretaceous : Banne-
witz, near Dresden. D, S. convoluta, Goldf. Middle Jura; Stuif'en, Wurtemberg. E, S. socialis, Goldf. Middle
Jura ; Lahr, Baden. F, Same, enlarged. G, S. septemsulcata, Reich. Upper Cretaceous ; Bannewitz. H, S.
(Rotularia, Defr.) spirulaea, Lain. Eocene ; Monte Berici, near Vicenza. /, Terebella lapilloides, Miinst. Upper
Jura ; Streitberg, Franconia.

swimming. Inhabiting more or less firm tubes, which they construct for themselves,
and subsisting upon vegetable matter.

The Tubicolous Annelides invest themselves with a protective tube of
usually irregular form, to which they are not organically connected, and in

SUB-ORDER A

YKIt.MKS 253

which they can move freely. Sometimes the tubes are free, but more com-
monly they arc attached to foreign objects, either by the apex or by one side,
and may occur either singly or in clusters. The tubes frequently consist of
concentric layers of lime -carbonate, with vesicular cavities between the
lamellae, or the latter may be traversed by fine tubuli. In other cases the
tubes are composed of agglutinated grains of sand and other foreign particles ;
or they may be membranaceous or leathery. The materials for constructing
the tubes are procured by the tentacles or branchial filaments of the head,
and are cemented together by a glutinous secretion from large glands. Fossil
worm-tubes are by no means of infrequent occurrence, and are known from
rocks as old as the Ordovician. Only a few of the more common examples
can be mentioned here.

Serpula, Lin. (Fig. 403). Under this head are included the majority of
fossil Tubicolar Annelides. They build firm, irregularly contorted, sometimes
spirally enrolled, free or adherent calcareous tubes, which are frequently
clustered together in large numbers. Beginning in the Silurian, they are
sparsely represented in the Palaeozoic era; but from the Jura onward,
numerous forms are met with, the usual condition being parasitic upon, other
fossils. Notably in the Lower Cretaceous their gregarious masses form beds
of considerable thickness (Serpulitenkalk of
Braunschweig, Serpulitensand of Bannewitz,
near Dresden). S. spirulaea, Lam. (Fig. 403 H)
is an abundant and characteristic Eocene
species. Living Serpulas have a world-wide
distribution.

Terebella, Cuv. (Fig. 403 /). Cylindrical,
elongate, more or less bent tubes, composed
of cemented grains of sand or other adventi-
tious particles. Lias to Recent.

Spirorbis, Daudin (Microconchus, Murch.),

(Fig. 404). Minute, snail-like, or spirally FIG 4Q4

enrolled calcareous tubes, cemented by the SpirorMs omplialod^ Gom. sp. Tubes at-
flat under side. The spiral may be either ***«! to a «rooh«>po<i shell (om^i,,^

r . J umbraculum). Devonian ; Gerolstem, Eifel.

dextral or smistral, and is usually orna-
mented externally with concentric striae or annulations, sometimes with
tubercles or spines. Abundant in the Palaeozoic formations from the
Ordovician onward, and also at the present day ; somewhat less common
in the Mesozoic and Cenozoic eras. Living species usually adherent on
seaweeds.

The following genera are commonly regarded as Annelides, but their
position is doubtful : —

Serpulites, Murch. Very long, smooth, compressed, and somewhat bent
calcareous tubes, the layers admixed with organic substance. Silurian.

Cornulites, Schloth. Thick -walled, trumpet -shaped tubes, closed at the
lower end, and sometimes attaining a length of three or four inches. Exterior
annulated, and covered with very fine longitudinal striae. Ordovician to
Devonian.

Ortonia, Nich. Small, conical, slightly flexuous, thick-walled calcareous
tubes, cemented by the whole of one surface to some foreign body. Sides of

254

VERMES

SUB-KINGDOM IV

the tube ringed with imbricating annulations, the free upper surface apparently
cellular in structure. Ordovician to Carboniferous.

Conchicolites, Nich. Conical, slightly bent, thin -walled tubes, growing
together in clusters, and attached by the small lower ends to Orthoceras or
Brachiopod shells. Tubes made up of numerous short rings, each of which
partially overlaps the one below. Ordovician.

Sub-Order B. EREANTIA. (Nereidae.)

Free-swimming, predaceous Polychaeta, with well - marked head. Proboscis
capable of protrusion, and armed with papillae or powerful jaws. Parapodia much

more developed than in the Tubicola, beset with
setae, and serving for locomotion.

Undoubted remains of Errant Worms have
long been known from the Lithographic Slates
(Upper Jura) of Bavaria, and include the
trails, calcified jaws, and excrements of numer-
ous species. The principal genus from this
horizon is Eunicites, Ehlers (Geophilus, Germar),
(Fig. 405), perfect impressions of which are
also found in the Eocene shales of Monte
Bolca.

Under the head of Lumbricaria, Miinster
(Lumbricites, Schlotheim), (Fig. 406), are in-
cluded a variety of obscure remains from the
Lithographic Slates, which maybe best regarded

FIG. 405.

Eunicites avitus, Ehlers. Lithographic
Slates ; Eichstiidt, Bavaria. Natural size.

FIG. 406.

Lumbricaria colon, Miinst. Lithographic Slates ; Solen-
hofen, Bavaria. Natural size.

as the excrements of Annelides. They occur as irregularly contorted bands or
strings, sometimes in the form of labyrinthic coils, and are usually of con-
siderable length.

The Myzostomidae, which are parasitic on living Comatulas, are shown by
Graff to have infested also the column segments of Jurassic Crinoids.

SUB-ORDER B

VERMES

Of peculiar interest are the minute detached jaws and toothed plates dis-
covered by Hindu in the Ordovician, Silurian, Devonian, and Carboniferous
rocks of Canada, Great Britain, and Sweden (Island of Gottland). These are

(Sf ,

Fia. 407.

Palaeozoic Annrlidi'-.jiiws. A, Lnmbricmiereit<'sbas<ilis, Hinde. Silurian ; Dundas, Ontario. N>/I. n,0enonites
,;>*(,•<• tut, Hinde. Toronto. »A. C, Eunicites varians, Grinnell. Toronto. «/!. D, ylra&eHites sciUellalu*,
Hiude. Ordovician ; Toronto. l«/i.

very small, black, highly lustrous bodies, extremely variable in form (Fig.
407), and mainly composed of chitinous material which is unaffected by acid.

FIG. 408.

..: Conodonts, highly magnified. A, B, Paltodvs truncatus, Pand. (after Pander). C, Prioniodus elegant, Pand.
Cambrian ; St. Petersburg. D, Polygnathus dubius, Hinde. Devonian ; North Evans, New York. 80/j.

They exhibit a striking resemblance to the jaws of recent Annelides, and
probably represent a large number of genera.

Of less certain derivation are the microscopic teeth so well described by
Pander under the name of
" Conodonts " (Fig. 408), which
occur detached in the Cambrian
(Blue Clay underlying the Un-
gulite Grit) of St. "Petersburg,
and are also very abundant in
beds of Ordovician, Silurian,
and Carboniferous age in
Russia, Great Britain, the
United States, and Canada.
They are usually translucent,
of a shiny, reddish horn-colour,
and are composed of carbonate
and phosphate of lime. They,

too, exhibit great variety in FIQ- 409.

form. By Pander and others y^rSfize"™*™1™' M<Leay> Cambrian: Liampeter, waic«.
these fossils have been re-
garded as fish -teeth. Zittel and Rohon, however, consider that they are
Annelid jaws, but their true position cannot yet be said to be satisfactorily
determined.

A quantity of supposed worm -borings, trails, impressions, and other

256

VERMES

SUB-KINGDOM IV

obscure remains have been described from the older Palaeozoic formations.
The burrows have the form of straight or tortuous tunnels, and are sometimes
hollow, but more commonly have been filled up by the matrix of the rock.

Various names have been applied
to them,* such as Scolithus, Areni-
cola, Histioderma, Planolites, Diplo-
craterihi, Spirocolex, Scolecoderma,
etc., but they are obviously in-
capable of precise determination.
Similarly, the serpentine or
vermiform impressions known
as Nereites, consisting usually of
a number of windings, and often
of profuse occurrence in various
Palaeozoic formations, were
until quite recently regarded as
worm-tubes, or markings made
by Fucoids. These also have
received numerous appellations,
such as Nereites (Fig. 409),
Nemertites, Myrianites, Nemapodia,
Crossopodia (Fig. 410), Phyllodo-

Naites, etc. Nathorst, however, has brought forward experimental
evidence to demonstrate that the majority of these markings have been pro-
duced by the movements of Crustaceans, Annelides, and Gastropods. A
like origin may be reasonably ascribed to the extraordinarily abundant and
variable vermiform structures known as "Hieroglyphics," which occur in the^
Flysch, Carpathian Sandstone, and in the marine facies of the Cretaceous and
Jurassic formations.

FIG. 410.

Crossopodia (Crossochorda) scotica,
Bagnoles, Normandy.

M'Coy. Ordovician

Sub Kingdom V. MOLLUSCOIDEA.

UNDER the term Mottuscoidea, Milne-Edwards included the Bryozoa and
Tunicata, of which the first had been previously regarded as Zoophytes, and
the second as Mollusks. Huxley afterwards assigned the Brachiopoda to the
same phylum. These three classes form a group intermediate in position
between the Worms and Mollusks, and are considered by many zoologists as
directly related to the one or the other. The Tunicata have more recently
been regarded as an independent animal type, and as the probable progenitors
of the Vertebrates. To the palaeontologist, however, they are devoid of
practical interest, owing to their total lack of hard parts.

The typical Molluscoidea either secrete a calcareous shell, or are invested
with a membranaceous or corneous covering. The respiratory organs lie
anterior to the mouth, and are in the form of tentacles or fleshy spiral
appendages. The m6uth conducts into a closed alimentary canal. The
nervous system is highly organised, and proceeds from a central ganglion,
situated in most cases between the mouth and the anus. Reproduction is
either sexual or takes place by budding. The ontogeny of the Molluscoidea
is most nearly comparable with that of the Annelids.

All of the Molluscoidea are water inhabitants ; the Bryozoans are largely,
and the Brachiopods exclusively, marine forms.

Class I. BRYOZOA. Ehrenberg.1

Small, almost always composite animals forming by gemmation variously shaped
colonies, each zooid of which is enclosed in a membranaceous or calcareous double-

1 Literature :

iVOrbigny, A., Paleontologie Frai^aise ; Terrain cretace, vol. V., 1850-51.
Hayenow, P., Die Bryozoen der Maestricher Kreidebilduug. Cassel, 1851.
Haime, J., Description des Bryozoaires fossiles de la Formation jurassique (Mem. Soc. Geol., France,

2nd ser. vol. V.), 1854.
Busk, G., Catalogue of Marine Polyzoa in the Collection of the British Museum (Parts I. and II.,

Cheilostomata), 1852-54. (Part III., Cyclostomata), 1875.
/>'">•/•, '/., .Monograph of the fossil Polyzoa of the Crag (Palaednt. Soc.), 1859.
Gabb, .W. M., and Horn, G. H., Monograph of the fossil Polyzoa of the Secondary and Tertiary

Formations of North America (Journ. Acad. Nat. Sci. Philad., 2nd ser., vol. V.), 1862.
Beissd, I., Ueber die Bryozoen der Aachner Kreidebildung. Haarlem, 1865.
Reuss, A. E., Several important papers in Denkschr. d. Wiener Akad., vols. XXIII., XXXIV.

1863-74 ; and Palaeontographica, vol. XX., 1872-74.
Manzoni, A., Several important contributions on Tertiary Bryozoans in Denkschr. d. Wiener Akad..

vols. XXIX., XXXI., XXXVIL, XXXVIII., 1869-78.
VOL. I S

258 MOLLUSCOIDEA— BRYOZOA SUB-KINGDOM v

walled sac (zocecium), and possesses typically a freely suspended alimentary canal
with mouth and anus. Mouth- surrounded by a crown of hollow, slender, ciliated
arranged in the form of a circle or crescent. Usually hermaphrodite.

The Bryozoa, or Polyzoa, most nearly resemble certain Corals (Talulata) and
Hydrozoans in their -external configuration, but differ from them radically in the
possession of a closed alimentary canal, a highly developed nervous system, and
delicate respiratory tentacles surrounding the mouth. With the exception of the
solitary genus Loxosoma, all Bryozoans live together in colonies or zoaria, of greater or
lesser extent, and of either calcareous, corneous, or membranaceous composition. These
colonies, which are formed by frequently repeated gemmation, present a multitudinous
variety of form, habit, and structure. Sometimes they grow into plant-like tufts,
composed of a series of cells variously linked together ; very commonly they spread
over shells and other foreign bodies, forming delicate interwoven threads, crusts of
exquisite pattern, or hemispherical, globular, or nodular masses of considerable size ;
often they rise into branching stems, and fronds of varying width ; and at other times
the cell-bearing branches form most regular and beautiful open-meshed lace-work.

Each individual is enclosed in a separate chamber (zocedum) of either utricular or
more or less tubular form. Occasionally the zocecia are quite distinct from their
neighbours ; more commonly, however, intercommunication is effected, either by
means of minute " connecting foramina " piercing the chamber walls, or by a common
canal to which all the zooids are attached. A true coenenchyma, such as is found
among the Coelenterates, never occurs, and coenenchymal gemmation is accordingly
unknown ; but a somewhat similar " vesicular tissue " not infrequently occupies the
interzooecial spaces which have resulted from the erection of the zocecial tubes.

Such vesicular tissue occurs constantly in the Fistuliporidae and Cystodidyonidae, and in
the latter the primary, or even the prostrate cells, are not entirely contiguous. The upper
walls of the vesicles, at least, are abundantly perforated ; and when with increasing age the
vesicles become tilled with a secondary deposit, these pores are not obliterated, but continue to
pass through such deposits in the form of minute vertical tubes. Precisely the same kind of
tissue occurs in other Bryozoans, notably among adult individuals of certain Fenestellidae, in
which the expanded base of the colony is largely vesicular, and the fenestrules and spaces
between the carinae of the branches are filled with vesicles for some distance up. The real
purpose of this tissue is to support the zocecia and to strengthen the'zoarium.

However diverse the external aspect of the composite structure, the small builders
themselves conform to a simple and quite definite type. Briefly, the animal consists
of an alimentary canal, in which three distinct regions, an oesophagus, stomach, and
intestine, are recognisable. This is enclosed in a sac, and so bent upon itself that its two
extremities, or openings, approximate ; one of them, the oral, being either entirely or
partially surrounded by a row of slender, hollow, and ciliated tentacles, which serve
for respiration and for sweeping food toward the mouth. In most cases the anal
opening is situated without the ring of tentacles (Ectoprocta), rarely within the same
(Entoproctd). Heart and vascular system are wanting, but a nervous ganglion, sending

Waters, W. A., Numerous papers on Tertiary and Recent Bryozoa in Ann. and Mag. Nat. Hist.,

and Quar. Journ. Geol. Soc., 1879-92.

Hincks, T., History of the British Marine Polyzoa, 2 vols., 1880.
Vine, Q. R., Reports on fossil Polyzoa (British Assoc. Reports), 1881-85.
Ulrich, E. 0., American Palaeozoic Bryozoa (Journ. Cincinnati Soc. Nat. Hist., V.-VII. ),

1882-84.

Busk, G., Report on Polyzoa (Sci. Results Challenger Exped., Zoology, vols. X. and XVII.), 1884-86,
Hall, «/., Lower Helderberg, Corniferous, and Hamilton Bryozoa (Palaeont. N.Y., vol. VI.), 1886.
Ulrich, E. 0., Contributions to American Palaeontology, vol. I. Cincinnati, 1886.
Pergens, K, Revision des Bryozoaires du Cretace, etc. (Bull. Soc. Beige Geol., III. -VI.), 1889-92.
Ulrich, E. 0., Palaeozoic Bryozoa (Geol. Survey Illinois, vol. VIII.). 1890.
Ulrich, E. 0., Lower Silurian Bryozoa (Geol. Survey Minnesota, Final Report, vol. III.), 1892.

< i \ss i BRYOZOA i'".!>

out delicate nerve filaments to the tentacles and oesophagus, lies between the mouth
and anus. The upper or anterior part of the sac is generally flexible and admits of
being invaginated by the action of numerous, longitudinal, and transverse muscles,
which traverse the fluid-filled visceral cavity.

Reproductive organs are developed in various parts of the cavity, the spermatozoa
usually in the 1«> \\er, the ova in the upper portion. The ova may be developed in a
ipecial receptacle (marsupium) attached to the zocecium, or in an inflation of the
surface of the zoarium (yonocyst) ; in other cases, a modified zocecium (gonoecinm) is set
apart for reproductive functions. The general term ocecium or ovicell is applk-ulile t<»
all of these structures.

Many Bryozoans are provided with appendicular organs known as avicularia and
vibracula (Fig. 411). Their functions are somewhat doubtful, some authors regarding
them as food-procuring agents, and others as organs of defence.
The avicularia may be immovably attached to the zocecium ; but,
as a rule, especially among recent forms, they are pedunculate,
and capable of considerable swaying motion. Often, as in Bugula
and Bicellaria, they resemble the head of a bird, consisting of a
lu Imet-shaped upper piece, with a formidable hooked beak, and
a mandible worked by powerful muscles. The jaws open and
close with a perpetual snapping motion, and small organisms or
other foreign particles happening in their way are seized and held
with a tenacious grasp. The vibracula are flexible, bristle-like
appendages, generally set in the excavated summit of a knob-like
elevation, or on a blunt spine.

The avicularia and vibracula are themselves incapable of
preservation, but their former presence on fossil specimens may
be generally determined by the slight pore-like excavations in
which they were lodged. The tubular spines, or acanthopores, BJge£ 'n££el™ '
which are of such common occurrence in Palaeozoic Bryozoans, portion of upper surface
were, in part at least, probably the supports of similar structures.

The term lunarium is applied to a more or less thickened
portion of the posterior wall in many Palaeozoic Bryozoans, which is curved to a
shorter radius and usually projects above the plane of the zocecial apertura Mesopores
are angular or irregular cells occupying interzocecial spaces in certain Palaeozoic genera.

Most Bryozoans are attached, either by the greater part of their surface, or only
basally, to extraneous objects ; or they are moored to the bottom by root-like appen-
dages. In many forms the zoarium is regularly jointed. The majority of genera
inhabit the sea, and occur in all zones and at all depths ; only a few genera live in
fresh water. The animals subsist chiefly on Diatoms, Infusorians, and larvae.

Classification. — The classification of the Bryozoans remains as yet in an unsatis-
factory condition. D'Orbign/s comprehensive system is largely artificial, and
although numerous modifications and improvements have been suggested by later
authors, a thorough revision has still to be undertaken.

Lankester divides the class into two very unequal sub-classes as follows : (1)
Holobranchia, in which the lophophore or row of tentacles is unbroken, and either
circular or horse-shoe shaped ; and (2) Pterobranchia, containing the single genus
Rhabdopleura, which has the lophophore produced on either side into a plume-like
process, so that the tentacles form a discontinuous series.

The Holobranchia are again divisible into two unequal groups, named by Nitsche
Ectoprocta and Entoprocta, according as the lophophore surrounds the mouth only, or
encloses both the oral and anal orifices. The first of these groups contains the bulk of
the known Bryozoa ; and, furthermore, the marine forms, and all genera capable of
preservation in the fossil state, are included in the single order Gymnolaemata. This

260 MOLLUSCOIDEA— BRYOZOA SUB-KINGDOM v

is distinguished from the remaining order, Phylactolaemata, Allman, by the complete
abortion of the foot, and by the circular arrangement of the tentacles.

The Mesozoic and recent marine Gymnolaemata are almost universally divided into
the three sub-orders proposed by Busk, the Cyclostomata, Chilostomata, and Ctenostom.ata.
To these Vine has added a fourth, the Cryptostomata, and* Ulrich a fifth, the Trepo-
stomata ; both of which serve mainly for the reception of Palaeozoic forms.

The detailed classification of the Mesozoic and recent Bryozoa, especially of the
Chilostomata, is less settled than that of the ancient types. This non-conformity is
due in part to the widely different views prevailing among authors as to the relative
value of the various characters upon which the groups are founded ; and partly
because the mode of growth, and zoarial characters in general, are much less constant,
and, therefore, less reliable than is the case among Palaeozoic representatives of the
class.

Order 1. GYMNOLAEMATA. Allman.
Sub-Order A. CYCLOSTOMATA. Busk.

(Bryozoaires centrifugine's, d'Orbigny, p.p.)

Zocecia very simple, calcareous, tubular, usually without transverse partitions; the
orifices plain, inoperculate, not contracted, occasionally expanded; walls thin, minutely
porous ; apertural portion oft zocecial tubes more or lees raised, bent outwards, free or in
bundles ; the interspaces with or without solid or .tubular strengthening deposits. Marsupia
and appendicular organs wanting. .Ocecium a large cell set apart for reproductive functions,
or a mere inflation of the zoarial surface.

The families and genera of this sub-order are founded almost entirely upon the form of the
zoarium, and the arrangement of the zooecia. The presence or absence of interstitial or
accessory cells and vesicular tissue (all strengthening deposits) is also an important character.

Until quite recently it was customary to regard all Palaeozoic Bryozoans as Gydostomata, but
the labours of Ulrich and Vine have clearly demonstrated the fallacy of such an assumption.
The families Ceramoporidae and Fistuliporidae are somewhat doubtfully referred to this sub-
order, because they agree with its most typical members in having amalgamated and minutely
porous walls. Moreover, the latest investigations of Ulrich have shown that the Ceramoporidae,
which were clearly the progenitors of the Fistuliporidae, were in turn derived from an as yet
undescribed group of Chazy Bryozoans greatly resembling Berenicea and Apsendesea.

Family 1. Crisiidae. Busk.

Zoaria dendroid, attached by radical tubes and composed of segments united by corneous
joints. Zocecia tubular, disposed in single or double series. Tertiary and Recent.

Crisia, Lam. Zoaria more or less distinctly articulated, the zocecia in a single or
in two alternating series.

Family 2. Diastoporidae. Busk (emend.)

Zoaria adnate, adhering by the entire base or only at the centre, at other times rising
into bifoliate leaves or hollow stems. Zooscia tubular, the aperture salient, rounded, never
clustered. Interstitial cells wanting. Ovicells mere irregular inflations of the surface of
the zoarium, ivith one or more openings. Ordovician to Recent.

Stomatopora, Bronn (Alecto, Lam. non Leach), (Figs. 412 and 413). Zoaria delicate,
adnate, dichotomously branching. Zooecia sub-tubular, clavate, or elongate-ovate,
arranged in one or more series ; apertures sub-terminal, usually smaller than the
width of the cell. Ordovician, Jura, Cretaceous, Tertiary, and Recent.

Silurian species like S. inflata, Hall, perhaps do not strictly belong to this genus.

ORDER i CYCLOSTOMATA 261

D'Orbigny, Haime, and others, restrict Stomatopora to the uniserial forms and classify

c

A ... . . I hicb. Utica Group; Cincinnati, <>.

Zocecia,W/i. /:. >'. !njl"t". Hall. Loraine Group ; Cincinnati, 6/j. 0,8.
, fronton, Xii-h. Same locality. Portion of large zoarium,
'-' ! (after Ulrich).

Fi... 413.

pom ili'-l,i,ti,,n'i, Lamx.
sp. Great Oolite ; Kanvillf,
Calvadus. A, Zoarium, */!• #,
same, enlarged.

tin- multiserial as Proboscina, Andouin. Should the latter genus have to be withdrawn,
Ulrich would place the multiserial species with Berenicea.

Berenicea, Lam. (Diastopora, Busk non Lam.), (Fig. 414). Zoaria forming thin,
discoid, flabellate, or irregular crusts upon foreign bodies. Zooecia arranged in
irregularly alternating lines. Rare in Ordovician, very abundant in Jura and
Cretaceous, less frequent in Tertiary and Recent.

Discosparsa, d'Orb. Differs from Berenicea in having obconical or cup-shaped
zoaria, attached by centre of the base only. Cretaceous.

Diastopora, Lam. (Mesenteripora, Blv.), (Fig. 415). Like Berenicea, except that the

414.

''•iinm, Lamx. Great Oulit • ;
Hanville, (.'alvados. .1, Vmuiu' i'X]>;m>i>i;i,
Vl- B, Same, enlarged (after Haime).

Fio. 415.

Unri'i, Ijunx. sp. Great Oolite ;
Ranvillc, Calvadus. .1, Frajrim-iit of zoarium, Vl-
l;, Enlarged portion of same.

zoarium rises into broad, simple, or convoluted leaves, composed of two layers of
»u riu grown back to back. Very abundant in the Jura, less common in Cretaceous
and Tertiary.

Bidiastopora, d'Orb. Like Diastopora, but the zoaria forming only narrow, parallel-
edged branches. Cretaceous.

Diastoporina, Ulrich, Ordovician ; Hederella and Hernodia, Hall, Devonian ; and
Reptaria, Rolle, Devonian.

262

MOLLUSCOIDEA— BRYOZOA

SUB-KINGDOM V

Family 3. Idmoneidae. Busk.

Zoaria forming free or adnate, variously compressed branches. Zocecial apertures
rounded, more or less elevated, usually arranged in transverse rows on two faces of the
branches ; sometimes the two faces are confluent. Dorsal surface of the branches without
zocecia, but often occupied by numerous small tubular pores, which may also occur near the
apertures. Sac-like ovicells with but a single opening. Ordovician to Recent.

Idmonea, Lam. (Reptotubigera, Crisina, d'Orb.), (Fig. 416). Repent or erect, simple
or branching. Branches usually triangular, two of the faces carrying the zocecial

apertures, which are generally
arranged in alternating transverse
series. Jura to Recent.

Bisidmonea, d'Orb. Quadrate,
simple, or branching stems, bear-
ing zocecial apertures on all faces.
Cretaceous.

Filisparsa, d'Orb. Branches
compressed dorso-frontally ; aper-
tures irregularly disposed ; other-
wise like Idmonea. Cretaceous.

Filicavea and Filicrisina,
d'Orb. Cretaceous.

Hornera, Lam. Zoaria with
side, highly N.Y. 'Branches of a ffee op anaatomosing| generally

sub-cylindrical branches. Zooecial
apertures more or less irregularly distributed. Cretaceous to Recent.

Reticulipora and Retecava, d'Orb. Zoaria reticulated ; branches greatly compressed
laterally. Cretaceous.

Bicrisina and Sulcocava, d'Orb. (Laterocava, d'Orb.) Cretaceous.

Protocrisina, Ulrich (Fig. 417). Narrow, bifurcating branches, celluliferous on one
side only. Zocecia sub-tubular, with prominent circular apertures arranged in inter-
secting diagonal series. Small pores, apparently communicating with interior of the
zocecia, irregularly distributed over both faces of the branches. Ordovician.

FIG. 416.

Idmonea dorsattt, Hagw. Upper Cre
taceous ; Maestricht. A, Branch,

3r, and C, Lower
niagn

FIG. 417.

Protocrisina exigua,
Ulrich. Trenton
Group ; Trenton,
N.Y. Branches of a
large expansion, 1%.

Family 4. Entalophoridae. Reuss.

Zoaria ramose ; branches free, sub-cylindrical, with rounded and more or less promin-
ently exserted zocecial apertures opening on all sides.
(?) Without accessory or interstitial pores of any kind.
Ordovician to Recent.

Entalophora, Lam. (Pustulopora, Blv.), (Fig. 418).
Zocecial tubes disposed about an imaginary axis, and
with rounded, more or less prominent apertures. Jura
to Recent.

Spiropora, Lam. (Laterotubigera, d'Orb.), (Fig. 419).
Like the preceding, but apertures arranged in regular,
spiral, or transverse linear series, and closely situated.
Zocecial tubes disposed about a definite central axis or
axial tube. Jura to Recent. g ula^H™ g\v.

Mitroclema, Ulrich, Ordovician ; Clonopora, Hall, Planer ; Plauen,
Devonian ; Peripora, d'Orb., Cretaceous.

Diploclema, Ulrich. Similar to Entalophora, but with branches spreading in the

FIG. 418.

FIG. 419.

Spiropora ver-
ticillata, Goldf.
Upper Cretace-
ous ; Maestricht
(after Hagenow).

CYCLOSTOMATA

263

ORDER I

same plane, slightly compressed, and divided into two equal parts by a wavy mesial
lamina. Silurian.

? Clausa, d'Orb. (Claviclausa, (?) Sparsicavea, d'Orb.) Like Entalophora, but having
the zocecial apertures surrounded by shallow interstitial cells, the mouths of which are.
covered in the perfect condition. Cretaceous.

? Petalophora, Lonsd. (Cavea, d'Orb. ; Canalipora, Hagw.) Cretaceous.

Family 5. Fasciporidae. d'Orbigny (emend.)

Zocecia tubular, opening in dusters at the groiving extremities, and in linear or quin-
cuncial series on the sides of the lamelliform,
or obconical zoaria. Accessory pores wanting.
Cretaceous.

Fascipora, d'Orb. (Fasciporina, d'Orb.) Zoaria
compressed, sub-ramose to lamelliform. Aper-
tures arranged quincuncially or somewhat
irregularly on both sides, and on the more
or less expanded growing extremities of the
branches and lamellae. The lamelliform species
resemble Diastopora, but are without a mesial
lamina.

Semifascipora, d'Orb. (Fig. 420). Zoaria cup-
or funnel-shaped, with only the outer surface
poriferous, the inner covered by an epitheca.
Poriferous face thrown into vertical ridges bear-
ing the salient tubular mouths of one or more
rows of zocecia. At the upper edge the ridges
pass into large clusters of apertures.

Conotubigera and Serietubigera, d'Orb. Closely
related to the preceding.

FIG. 420.

Semifascipyra varidbilis, d'Orb. Cretaceous
France. Side view of zoarium, 10/i.

Family 6. Fascigeridae. d'Orbigny (emend.)

Zoaria repent or erect, lamelliform or branching, generally the latter. Zoo2cial apertures
arranged in bundles or clusters, in which they are contiguous. Jura
P~7" gg"\ to Recent.

~\ *'y Filifasdgera, d'Orb. (Fig. 421). Zoaria repent, irregularly

Ejf branching. Apertures erect, in successive groups of from twro to
<^\ I fit nve O1 more' Growth terminal. Cretaceous and Tertiary,
i*- N. -J f$ Reptofascigera, d'Orb. (Semitubigera, d'Orb.) Zoaria repent,

growth terminal. Apertures in two series of clusters directed
alternately to the right and left. Cretaceous.

Theonoa, Lam. (Tilesia, Lam. ; Fascicularia, M. Edw. ;
Lopholepis, Hagw. ; Multifascigera, etc., d'Orb.), (Fig. 422).
Z'Miiu lamelliform or massive, usually free, with an epitheca on
lower face ; sometimes in superposed layers. Apertures in
elevated clusters, somewhat irregularly distributed, more or less
megaem, elongated. Growth peripheral. Jura to Tertiary.
L.iiis.1. Upper Cretaceous ; Fasciculipora, d'Orb. (Fungella, Hagw.), (Fig. 423). Zoaria
Vincentown, N.J. Speci- . , r ', , . \ j T T •/ j ^ ^

men seen from above and erect, simple, or branching. Apertures crowded, limited to the
side, u/i (after convex an(j usually expanded upper extremities of the branches.

Sides of stems usually without pores. Jura to Tertiary.
Frondipora, Imperato. Zoaria bushy, attached at the base ; branches free or

264

MOLLUSCOIDEA— BRYOZOA

SUB-KINGDOM V

anastomosing. Zocecial apertures on one side only ; branches otherwise without pores.
Cretaceous to Recent.

Unicytis, d'Orb. Like the preceding, except that the non-elevated portions of the
surface of the branches are occupied by interstitial cells. Cretaceous.

FIG. 422.

Theonoa aurantiwn, M. Edw. Crag ; Sussex. A, Zoarium broken
open in a vertical plane, Vi- -B. Enlarged portion of upper surface.

FIG. 423.

Fasdculipora incrassata, d'Orb. Upper
Cretaceous ; Meudon, near Paris. Ter-
minal fragment, nat. size and enlarged
(after d'Orbigny). t.

1 an
(after Ulr

Osculipora, d'Orb. (Fig. 424). Differs from Frondipora in having the apertures in two

alternating rows of more or less strongly project-
ing clusters. Cretaceous.

Truncatula, Hagw. (Fig. 425). Distinguished
from Osculipora by having one face only covered
with epitheca, the other (convex side) exhibit-
ing numerous longitudinally arranged interstitial
cells. Cretaceous.

Desmeopora, Lonsd. (Semicytis, d'Orb.) ; Dis-
cofascigera, d'Orb. Cretaceous.

• Cyrtopora, Hagw. Sub - cylindrical stems
with prominent clusters of four or more zooecial
apertures scattered over the entire surface. In-
terspaces smooth. Cretaceous to Recent.

Plethopora, Hagw. Clusters larger than in the
preceding, and the depressed interspaces occupied
by small cells. Cretaceous.

FIG. 424.

Osculipora trun-
cata, Hagw. Up-
per Cretaceous ;
Maestricht, Hol-
land. Fragment,
and enlarged

FIG. 425.

ich).

Truncatula repens,
Hagw. Upper Cretace-
ous ; Maestricht. Lower
and upper sides of
zoarium, enlarged (after
Hagenow).

Family 7. Lichenoporidae.

Zoaria simple or composite, discoid or massive, adhering by more or less of the under
surface. Zocecial apertures on the upper surface, arranged in radial series. Jura to
Recent.

Discocytis, d'Orb. (Pelagia, Mich, non Lam. ; Bicavea, Radiocavea, d'Orb.), (Figs. 426,
427). Zoaria cup-shaped, obconical, or discoid, often pedunculate, poriferous on the under
and outer sides. The concave upper side with a decidedly radial structure ; zooecial
apertures scarcely distinguishable from pores on the sides of the zoarium. Cretaceous.

Apsendesia, Lam. (Pelagia, Lam. ; Defrancea, Bronn ; Eadiofascigera, etc., d'Orb. ;
? BusJcia, Reuss), (Figs. 428, 429). Zoaria simple or composite, discoid or lamelliform,
attached by a peduncle or by the whole under surface. Interstitial cells wanting.
Jura to Recent.

Lichenopora, Defr. (Discocavea, Radiocavea, etc., d'Orb. ; Stellipora, Hagw. non Hall ;

ORDER i CYCLOSTOMATA 265

Discoporella, Gray), (Figs. 430, 431 ). Like Apsendesia, except that interstitial cells occur

Fio. 4LV,.

l>:.-n;t,-iit!.t c mil-til, d'Orb. Upper Cretaceous ; France. Specimen 3/4
natural size, and three views of same enlarged (after d'Orbigny).

Fio. 427.

:l!il<l'-IIIH, (illl'lf. sp.

t"]i|»T ('retari't.us ; Mat-strirlit.
.1, /(inriiini, '/i- /.'. 1'rotile of
same. C, Upper surface, enlarged.

between the elevated rows of zoo2cial apertures, on a depressed space at the centre of
each disk, and often also on the under surface of the zoarium. Jura to Recent.

Fio. 428.

Apsendesid Gaudryana, d'Orb.
Upper Cretaceous ; France.
Upper surface, 8/j.

Fio. 429.

Apsendesia (Buskia) tabulifera, Roeiner sp. Astrupp, Westphalia. A,
Zoarium, i/z. J5, Cluster of zocecial apertures, enlarged.

Stellocavea, d'Orb. Zoaria discoidal, the upper surface exhibiting the salient edges of

FIG 430

Lichennpora (Rudiopora) stellata, Goldf. sp. Planer; Plauen, Saxony

5: ££SStfL£ Same> enlarged- c> Ver"cal section of specimen from

numerous radially arranged plates, few of them reaching the centre. Zocecial tubes

266

MOLLUSCOIDEA— BRYOZOA

SUB-KINGDOM v

opening on the two opposite sides of plates. Depressed interspaces occupied by inter-
stitial cells. Cretaceous.

? Multicavea, d'Orb. Zoaria ramose, the stems poriferous on all sides, interstitial
cells composing the greater part. Apertures forming short »stellate series disposed at
close intervals over the surface of the branches. Cretaceous.

Family 8. Cerioporidae. Busk.

Zoaria multiform, encrusting, lamellar, bulbous, lobate, digitate, or ramose, composed of
closely arranged thin-walled tubes. The latter sometimes completely separated by angular
interstitial cells. Walls of neighbouring tubes thoroughly amalgamated and pierced by
numerous pores. Trias to Recent.

The Cerioporidae greatly resemble many of the Palaeozoic Trepostomata, but, as a rule, may
be readily distinguished by the complete amalgamation and porous nature of their zooecial walls.

Ceriopora, Goldf. (Ceriocava, d'Orb.), (Fig. 432). Zoaria encrusting, massive,
lobate, or ramose, often consisting of two or more superposed layers of tubes. The

latter are sub -equal, in close
contact, of one kind only, and
their round or polygonal aper-
tures cover the entire upper
surface of the colony. Very
abundant in the Alpine Trias,
sparse in the Jura, but frequent
again in the Cretaceous.

Heteropora, Blainv. (Multi-
cresis, Nodicresis, Zonopora,
Polytremata, etc., d'Orb), (Fig.
433). Zoarium variable, gener-
ally ramose, sometimes com-
posed of several layers of tubes.
Apertures rounded, the peristome often slightly raised. Interstitial tubes numerous,
angular, usually surrounding the zooecia completely, their orifices closed when perfect.

A C

FIG. 432.

Ceriopora spongites, Goldf. Greensand ; Essen. A, Zoarium, 1/1-
B, C, Upper and lower sides, enlarged.

FIG. 433.

Heteropora pustulosa, Mich. Great Oolite ; Ranville,
Calvados (after Haime). A, B, Zoarium, i/j. C, Ver-
tical section. D, Upper surface, enlarged.

FIG. 434.

Neuropora angulosa, Goldf. sp. Upper Jura;
Oerlingen, near Ulm. A, Natural size. B, Portion
of surface, enlarged.

They are frequently gathered into clusters and separate the true zocecia into zones or
patches. Very abundant in Jura and Cretaceous, rare in Tertiary and Recent.

Heteroporella, Busk,
and Tertiary.

Like the preceding, but growth-habit encrusting. Cretaceous

ORDER I

CYCLOSTOMATA

267

IDitaxia, Hagw. Zoaria ramose, brandies flattened, consisting of two layers of
tubes grown together back to back. Otherwise like Heteropora. Cretaceous.

Chilopora, Haime. Zoaria erect, lamelliform ; apertures rather large, rounded
or sub-triangular, oblique, with the lower half of the margin elevated. Interstitial
cells numerous, much smaller than the zooecia. Jura.

Neuropora, Bronn (Chrysaora, Lam. ; Filicava, d'Orb.), (Fig. 434). Zoaria generally
irregularly ramose, attached at the base, composed of sub-equal tubular zocecia. These
open on all exposed parts of the surface, save on certain variously arranged, more or
less raised, thin solid ridges. Jura and Cretaceous.

Acanthopora, d'Orb. Zoaria ramose, consisting of but one kind of zocecial tubes.
Surface studded with numerous solid conical or spine-like prominences. Jura and
Cretaceous.

Families doubtfully referable to the Cyclostomata.

Family 9. Ceramoporidae. Ulrich.

Zoaria usually encrusting, sometimes discoid, lamellate, massive, or forming more or
less regular hollow branches ; rarely bilobiate. Clusters of mesopores and of zocecia, larger
than the average, occur at regular intervals. Zooecial apertures usually oblique, of sub-
triangular, ovate, or polygonal form; lunarium present, appearing at the surface as a
prominent overarching hood, or as a slightly elevated portion of the margin, of crescentic
form, with the ends projecting more or less into the aperture. Mesopores or interstitial cells
generally present, aliL-ays irregular, and usually without diaphragms. A few horizontal
diaphragms of ten present in the zocecial tubes. Walls minutely porous, composed of intimately
connected and irregularly laminated tissue. Ordovician and Silurian.

This is one of the largest and most important of the families of Palaeozoic Bryozoans, and is
especially common in the Trenton and Cincinnati Groups. The earliest forms resemble
Berenicca and Apsendcsia ; while Ceramoporella, Chiloporella, and especially Bythotrypa, may
be regarded with reasonable confidence as the progenitors of the Fistuliporidae. At any rate
the connection between the two families is so intimate as to forbid any wide separation.

Ceramopora, Hall. Discoidal, free, or attached by the centre of the base. Under
surface with one or more layers of small irregular cells. Zocecia opening on the upper

FIG. 435.

Ceramoporella distinctu,
Ulrich. Lower Trenton,
Minnesota. Surface of para-
sitic expansion, is/, (after
Ulrich).

FIG. 436.

Crepipora perampla, Ulrich. Trenton; Minnesota. A, Vertical section.
-R, Transverse section, ?/]. C, Same, "/j, showing lunaria. D, Surface of C.
simulans, Ulrich, 9fr (after Ulrich).

surface, large, oblique, imbricating, and radially arranged about the depressed centre.
Mesopores irregular, short, numerous at the centre of the colony, decreasing toward the
periphery. Silurian.

Ceramoporella, Ulrich (Fig. 435). Zoaria encrusting, becoming massive by super-
imposition of numerous thin layers. Zocecial tubes short, walls thin, apertures more

268

MOLLUSCOIDEA— BRYOZOA

SUB-KINGDOM V

or less oblique, hooded, commonly of oval shape. Mesopores abundant, often com-
pletely isolating the zocecia. Apertures closed by a thin calcareous sheet at maturity.
Abundant in Ordovician. C. distincta, Ulrich.

Crepipora, Ulrich (Fig. 436). Encrusting, lamellate, or .massive, in one case forming
hollow branches. Zocecial tubes long, partitioned off by a moderate number of
diaphragms. Mesopores almost entirely restricted to the maculae, which are distributed
over the surface as minutely porous elevations or depres-
sions. Apertures very slightly oblique, angular, or
sub-pyriform. Lunarium well-defined in perfect speci-
mens, best shown in tangential sections. Ordovician,
? Silurian.

Anolotichia impolite,, Ulr. Lower Trenton ; Minnesota. A, Surface,
6/1. B, Vertical section, %. C, Tangential section, i2/]; showing tubes
of lunarium. D, Tangential section of A. ponderosa, Ulr., from the
Cincinnati formation at Wilmington, 111., showing numerous lunarial
tubes (after Ulrich).

FIG. 438.

Ceramophyllafrondosa, Ulr. Black
River Shales ; Minnesota. A, Zoar-
ium, 2/3 B, Surface of same, "/i-
C, Two zocecia of a tangential
section, 12/!. I), Right half of a
vertical section, l-/i (after Ulrich).

Anolotichia, Ulrich (Fig. 437). Zoaria large, ramose, or digitate, consisting of
long, sub-polygonal tubes intersected by remote diaphragms. Mesopores never very
numerous. Lunarium slightly elevated at the surface, traversed internally by two to
six minute, vertical, closely tabulated tubes. Ordovician.

Diamesopora, Hall (Coelodema, Ulrich). Hollow branches, lined internally with a

FIG. 439.

Diam'e'sopora
trentonensis, Ulr.
Trenton ; Minne-
sota. Two frag-
ments, 2/3, and
one °/i.

FlG- 44°-

Bythotrypa laxata, Ulr. Trenton ; Minnesota. A, Surface ,14/1- R Vertical
section, ?/lt C, Transverse section, u/j (after Ulrich).

striated epitheca. Zocecia as in Ceramoporella, but with thicker walls. Ordovician
and Silurian.

Ceramophylla and Chiloporella, Ulrich. Ordovician.

Bythotrypa, Ulrich (Fig. 440). Zoaria massive or lamellate. Zooecial tubes long,
intersected by thin diaphragms. Lunarium large ; mesopores numerous, open at the
surface, forming interiorly a very loose vesicular tissue. Ordovician.

Scenellopora, Ulrich. Zoaria simple, pedunculate ; under surface with an epitheca,

CYCLOSTOMATA

the upper slightly concave and celluliferous.
circular ap<-rtmv>, radially airan-cil
on the summits of low ridges. Y«-ry
-tive of yl /'•-•< n't' *«(. Certain
Chazy species are composite, and allied
to Ceramoporella. Ordovician.

Spatt'oj,,,,;; ririch (Fig. 441).
Zoaria forming thin crusts, especially
on Orthoccras. Apertures irregular;
lunarium scarcely perceptible. Meso-
pores, when present, chiefly in
maculae. Interspaces often with
large blunt spines (? acanthopores).
Ordovician.

Z«M , ja with slightly oblique, sub-

Flo. 441.

.Ulr. Cincinnati Group ; Hamilton, ().
.1, Surlar.-. /;, Vertical section. (,', Tangential section; all
14/j (after Ulrich).

Family 10. Fistuliporidae. Ulrich.

Zoaria massive, Inn him; or ramose, the surface exhibiting at regular intervals " maculae "
or "monticules" composed of clusters of vesicles and of zocecia slightly larger than the
average. Lunarium more or less developed. Zocecial tubes never angular, thin-walled, and
with horizontal diaphragms ; apertures closed by perforated operculum. Interspaces occupied
by vesicular tissue. Cell walls minutely porous. Silurian to Permian ; climax in
Devonian.

Waagen and Wentzel have recently referred this family to the Corals (cf. ante, p. 105), but
their reasons for doing so rest obviously upon insufficient observation. Not only are the
members of this family derived from the Ceramoporidae, as noted above, which are undoubted
Bryozoans, but some of them possess ovicells, thus abundantly proving their Bryozoan nature.

Fidnlipora, M'Coy (Lichenalia, Thallostiyma, Hall ; Didymopora, Ulrich; Dybow-
skiella, Waag. and W.), (Fig. 442). Zoaria massive, lamellate, more rarely ramose,
parasitic, or free ; under surface with wrinkled epitheca.
Zooecia sub-radially arranged about the surface maculae ;
apertures ovoid, sub-triangular, or pyriform, according
to the degree in which the lunariuin is developed ;
interiorly with thin walls, and a small number of com-
plete horizontal diaphragms. Interspaces smooth or
granular, occupied internally by one or more series of
vesicles. Common from Silurian to Sub-Carboniferous ;
less frequent in Coal Measures
and Permian.

Cyclotrypa, Ulrich (n. gen.
or sub-gen.), (Fig. 443). Like
Fistulipora, but the lunarium
obsolete, and zocecial tubes
circular in transverse section.
Devonian. Fist, communis and
F. collina, Ulrich.

Eridopora, Ulrich (Pileotrypa,

Hall). Zoaria thin, parasitic. Hamilton ; Nt-w Buffalo, Iowa.
r, -,1 IT i Tangential section, "A.

Zooecia with oblique, sub-
triangular, or ovoid apertures. Lunarium very prominent.

Chilotrypa, Ulrich (Coelocaulis, Hall). Zoaria small, ramose, with a narrow,
irregularly contracting and expanding axial tube. Apertures elliptical, oblique, the
lower margin thick and elevated, the wall thin above. Diaphragms few or absent.

Ulr.

Cyclotrypa communis, Ulr.
Hamilton ; New Buffalo, Iowa.
Vertical and tangential sections,
w/i (after Ulrich).

Niagara to Coal Measures.

270

MOLLUSCOIDEA— BRYOZOA

SUB-KINGDOM V

Interstitial vesicles filled by a dense calcareous deposit near the surface. Silurian and
Sub-Carboniferous.

Meekopora, Ulrich (Fig. 444). Zoaria bifoliate, sometimes branching, the median
laminae thin, flexuous. Oblique apertures all directed toward the distal margin of

FIG. 444.

Meekopora eximia, Ulr. Chester Group; Monroe Co., 111. A, Specimen
from the side and edge, 3/ B, Surface of same, 7/x. c, Portion showing
ovicell, 14/i (after Ulrich).

FIG. 445.

Strotopora foveolata, Ulr.
Keokuk Group ; Bentons-
port, Iowa. Part of ex-
pansion, 3/4, and surface of
same, 7/j, showing zocecial
apertures and broken ovi-
cells (after Ulrich).

the zoarium or branch,
often recurved. Ovicell

FIG. 446.

Buskopora dentata, Ulr.
Hamilton ; Falls of the Ohio.
Portions of surface, 7 fa and ^/j
(after Ulrich).

bound the hexagonal
obsolete. Devonian.
Pinacotrypa, Ulrich ;

Lunarium moderate or obsolete ; diaphragms numerous and
rather large, showing at the surface as a convex space with a
small apical opening. Sub-Carboniferous.

Strotopora, Ulrich (Fig. 445). Zoaria ramose, with
irregular branches. Large, abruptly spreading cells (re-
garded as broken ovicells), distributed among the zooecia on
ordinary specimens ; when perfectly preserved they appear
as strongly convex elevations with a small opening on one
side. Devonian and Sub-Carboniferous.

Lichenotrypa, Ulrich. First stages like Fistulipora, after
which large spines and irregular thin walls are thrown up
about the apertures. Devonian.

Buskopora, Ulrich (Odontotrypa, Glossotrypa, Hall), (Fig.
446). Like Fistulipora, but lunarium remarkably developed,
projecting as a strong, bidenticulate process nearly half
across the aperture. Devonian.

Selenopora, Hall (Favicella, Hall). Zoaria laminar, en-
crusting. Interzoo3cial spaces occupied by two series of
small vesicles, separated by strongly elevated walls. These
in which the zocecial apertures are situated. Lunarium

(?) Botryllopora, Nicholson. Devonian.

Family 11. Ceidae. d'Orbigny.

Zoaria ramose, bifoliate, or urn-lamellate. Zooecia tubular, sub-equal, their walls thin at
first, but thickening gradually toward the periphery, where the cavity suddenly dilates in
such manner that the rounded or elliptical aperture lies at the bottom of an hexagonal
depression. Interstitial cells wanting. Cretaceous.

The systematic position of this family is highly problematical. It appears to have certain
affinities with the Trcpostomata, but its removal to that vicinity is hardly feasible until a
thorough comparison of Palaeozoic and Mesozoic Bryozoans shall have been made.

Semicea, d'Orb. (Reptocea, d'Orb., p.p.) ; Discocea, Pergens.

Cea, d'Orb. Zoaria forming flattened branches or broad lamellae, celliferous on
both sides.

SUB-ORDER B

TREPOSTOMATA

271

Filicea, d'Orb. (Laterocea, d'Orb.), (Fig. 447). Zoaria erect, with sub-cylindrical
branches bearing apertures on all sides.

Zooecial tubes dilating outwardly, with

FlO. 447.

Filieea relata, Hagw. sp. Upper Cretaceous ; Maestricht, Holland. A, Branch, 1/1- B, Surface of same
enlarged. (', Vertical section (atter d'Orbigny).

Family 12. Melicerititidae.

Zoaria ramose, bifoliate, or uni-lamellate.
perforated walls. Front of zocecia
partly covered by a perforated plate.
Vicarious avicularia scattered among
the zocecia. Cretaceous.

The members of this family differ
widely from the true Cyclostomata.
They may be Mesozoic representatives
of the Palaeozoic Cryptostomata, some
of which, particularly Proutella, they
greatly resemble. But, on the other
hand, the presence of avicularia, which
are as yet entirely unknown among
Palaeozoic Bryozoans, perhaps in-
dicates even stronger affinities with
the Chilostomata.

Fia. 448.

Structure of walls and
Ulr.

parenchymal cord in Homotrypacallosa,
(A, 38/j); Stictoporella frondifera, Ulr. (B "
pora columnifera, Busk. Recent. (C, w/i.)

and Rete-

Semielea, d'Orb. (Reptelea, etc., d'Orb.) ; Eetelea, Clausimultelea, d'Orb.

Elea, d'Orb. Flattened, branching, or anastomosing stems, or broad leaves, pori-
ferous on both sides.

Meliceritites, Roemer (Escharites, Roeni. ; Inversaria, Hagw. ; Nodelea, Multeleu,
d'Orb.) Cylindrical branching stems, poriferous on all sides.

Sub-Order B. TREPOSTOMATA. Ulrich.1

Zo(ecia directly superimposed upon one another so as to form long tubes intersected by
straight or curved partitions (diaphragms and cystiphragms), representing the covers and

1 [Two regions of the zorecial tubes are distinguishable, an axial or " immature " region, in which
the diaphragms are remote, the walls thin, and the tubes prismatic through contact ; and a peri-
pheral or "mature " region, in which the tubes bend outward, the walls are thickened and otherwise
modified, the transverse partitions more abundant, and interzorecial elements (acanthopores, rneso-
pores, or mere strengthening tissue) are developed.

Waagen and Wentzel and others erroneously assert that the mesopores and acanthopores, occur-
ring so commonly in this sub-order, are young zocecia or " corallites." With very few exceptions,
these really very different elements are not developed until the zoarium has reached the mature
stage, in which new zocecia cease to be given off. The origin of mesopores (i.e. all cells occupying
iiiterzocecial spaces, whether invested with separate walls or not) is due to the same necessity which

272

MOLLUSCOIDEA— BRYOZOA

SUB-KINGDOM V

floors of successive layers. Zocecial covers with a small, usually sub-central orifice. Mon-
ticules or maculae (containing cells differing from the average in size, or in having their
apertures elevated) regularly distributed over the surface.

%

Family 1. Monticuliporidae. Nicholson (emend. Ulrich).

Zoaria massive, discoid or lamellar, ramose or bifoliate. Zocecial apertures polygonal,
rounded, or irregularly petaloid. Mesopores occasionally wanting, in other cases numerous,

angular, and crossed by crowded dia-
phragms. Acanthopores abundant,
usually small. Cystiphragms always
present in the mature region. Orclo-
vician to (?) Devonian.

The incomplete, curved, transverse
partitions, termed cystiphragms by
Ulrich, are the principal peculiarity of
this family. It is possible that they
represent ovicells, but their significance
can only be conjectured.

Monticulipora, d'Orb. (Fig. 449).
Zoaria massive, lobate, or lamellate,
encrusting or free. Surface with
monticules or plain. Zocccia poly-
gonal, mostly thin-walled. Mesopores very few or absent. Acanthopores more or
less numerous, small. Ordovician, (?) Devonian.

Atactoporella, Ulrich (Fig. 450). Zoaria generally encrusting, rarely lobate or
sub-ramose. Zooacia with very thin inflated walls, the apertures irregularly petaloid.

FIG. 449.

Monticulipora arborea, Ulr. Trenton ; Minnesota,
tical (A) and tangential (B) sections, !•*/! (after Ulrich).

Ver-

Fio. 450.

Atactoporella typicalis, Ulr. Black River Group ; Minnesota. Surface (A), tangential (£), and vertical (Q
sections, 14/x (after Ulrich).

Mesopores numerous, frequently isolating the zocecia, largely filled by a secondary
deposit. Ordovician.

Peronopora, Nich. (emend. Ulrich). Similar to the preceding, but zoaria bifoliate,
and zocecial walls thicker, not inflected by the acanthopores, and more ring-like in
transverse section. Ordovician.

leads to the distal thickening of the zooscial tubes, namely, that of filling up spaces occasioned by
the growth of tubes at the periphery, and by the change in direction of the tubes.

Some of the tubes provisionally included under the term mesopores, like some of the acantho-
pores, were doubtless occupied by specially modified polypides, which probably find their
homologues in the avicularia and vibracula of recent Chilostomata. But many of the mesopores
which are not invested by separate walls are to be regarded as mere interspaces between the
zocecial tubes, and the purpose of their transverse partitions is to support the walls of the latter,
.as well as to assist intercommunication by means of the zoarial parenchymal cord.]

SUB-ORDER B

TREPOSTOMATA

273

Homotrypa,\Jlrich (Fig. 451). Generally ramose, sometimes frondescent. Zooccial
tubes with very thin and finely crenulated walls, and remote diaphragms in the

section,

I IO. l-'.l.
Ulr. Trenton ; Minnesota. A, Surface. B, D, Tangential sections. C, Vertical

axial region. Cystiphragms, isolated or in series, developed in peripheral region only.
Apertures polygonal or sub-circular. Mesopores usually few and in clusters. Acan-
thopores generally present. Ordovician.

Prasopora, Nich. and Eth. (Fig. 452). Zoarium usually free in adult stage, with
wrinkled epitheca on lower surface. Zooecial tubes prismatic or cylindrical, thin-

Fio. 4:.L'.

Proton . L'lr. TnMitnn ;

Kentucky. 4,Tian8vene,an<] /;, Ver-
tical section, »/, (aft«r Ulrich).

Fio. 453.

, Ulr. Black River Group ; Minnesota. A, Trans-
verse section. B, C, Vertical sections, Wi (after Ulrich).

walled, separated from one another by smaller angular mesopores, and containing
cystiphragms. Acanthopores usually present. Ordovician.

Mesotrypa, Ulrich ; Ordovician. Aspidopora, Ulrich ; Ordovician and Silurian.

Family 2. Heterotrypidae. Ulrich.

Zoaria frondescent, ramose, or parasitic. Zocecia polygonal, with moderately thin walls.
Acanthopores present, sometimes of large size. Diaphragms numerous, horizontal. Cysti-
phragms wanting. Ordovician.

Dekayella, Ulrich (Fig. 454). Ramose, branches'sometimes compressed. .Mesopores
more or less numerously distributed among the zooecia. Acanthopores of two sizes,
the smaller ones the more abundant, and present only in the peripheral region.

Dekayia, Ed. and H. (Fig. 455). Distinguished from Dekayella by the absence of the
MI Killer set of acanthopores, and lesser number of mesopores and diaphragms.

Heterotrypa, Xich. (Fig. 185). Zoarium always frondescent, and acanthopores of
small size only ; otherwise like Dekayella. Abundant in Cincinnati Group.

VOL. I T

274

MOLLUSCOIDEA— BRYOZOA

SUB-KINGDOM V

Petigopora, Ulrich. Small parasitic species having strong acanthopores but no
mesopores, and only a few diaphragms.

FIG. 454.

jSOL

Dekayella dbscura, Ulr. Cincinnati, Ohio. Tangential
and vertical sections, *4/i (after Ulrich).

FIG. 455.

Dekayia aspero, Edw.
and H. Cincinnati, O.
Tangential section, n/j.

Family 3. Calloporidae. Ulrich.

Zoaria ramose, sub-frondescent, massive, or discoidal. Zoce.cial apertures generally sub-
circular and separated more or less completely by angular mesopores; at other times poly-

FlG. 456.

A, B, Callopora elegantula, Hall. Niagara ; Indiana. Vertical and tangential sections, u/i. C, D, C. multi-
tabulata, Ulr. Trenton ; Minnesota. C, Vertical section, T/I. D, Surface having zooecia open (7/j), and preserv-
ing zocecial covers (14/i).

gonal, when the mesopores are few or wanting. Zoo3cial tubes thin-walled, attaining their
full size slowly. Acanthopores wanting. Ordovician to Devonian.

In this family the proximal ends of the tubes arising in the axial or "immature" region
have the character of mesopores. The diaphragms are rather closely arranged in the tapering

FIG. 457.

FIG. 458.

Monotrypa magma, Ulr. Lower Trenton ;
Illinois. Transverse and vertical sections, 7/i

Diplotrypa IfV.v/o/u, Ulr. Cincinnati Group ; Manitoba.
Tangential and vertical sections, U/i (after Ulrich). (after Ulrich).

proximal end, then few or wanting for a considerable distance, and finally become crowded in
the peripheral or mature region.

RUB-ORDER B

TRKl'OSTOMATA

275

Callopora, Hall (emend. Ulrich), (Fig. 456). Zoaria usually ramose and bushy, the
branches often anastomosing. Apertures closed in the perfect state by perforated,
often ornamented, covers, which are It-It behind, as growth proceeds, to form floors
{diaphragms) of succeeding layers. Zocecial tubes of two sizes in the axial region, the
larger ones with six to eight sides, the smaller set four- or five-sided. Ordovician and*
Silurian,

Diplotrypa, Nich. emend. Ulrich (Dianulites, Zittel non Dybowski), (Fig. 457).
Zoaria discoid, globular, or irregularly massive, generally free. Zocucial tubes com-
paratively large, prismatic, with horizontal diaphragms. Mesopores few to numerous,
varying in size. Ordovician.

Monotrypa, Nich. (Dianulites, Dyb. p.p. ; ftychonema, Hall), (Fig. 458). Dis-
tinguished from the preceding by the absence of mesopores and fewer diaphragms.
Ordovician to Devonian.

Family 4. Trematoporidae. Ulrich.

Zoaria ramose or encrusting. Zo&cial tubes irregular in the axial region, their
proximal ends with diaphragms, and usually constricted where the latter occur; walls

FIG. 459.

Tangential sections of Batostoma from the Lower Trenton of Minnesota. A, B. fertile, Ulr.
var. circulare, M/j. C, B. Winchdli, var. spinulosum, Ulr., 38/: (after Ulrich).

i. B Same

thickened in the mature region, lines of contact distinct,
usually of large size, their apertures
closed. Acanthopores more or less
abundant. Ordovician.

Mesopores generally abundant,

This family is principally distinguished
m the Cailovoridae by the presence of

from the Calloporidae
acanthopores and closed mesopores.

Batostoma, Ulrich (Fig. 459).
Branches irregular, springing from a
large basal expansion. Zooecial walls
of varying thickness, in contact only
at limited points, and of two sizes in
the axial region. Diaphragms strong,
horizontal, complete. Species numer-
ous and mostly very abundant.

Hemiphragma, Ulrich (Fig. 460).
part of tubes incomplete.

Trematopora, Hall (emend. Ulrich) ; Stromatotrypa, Ulrich.

Fio. 460.

Hemiphragma irrasum, Ulr. Lower Trenton ; Minnesota.
A, Vertical section, 7/,. B, Tangential, w/j (after Ulrich).

Like Batostoma, but diaphragms in peripheral

276

MOLLUSCOIDEA— BEYOZOA

SUB-KINGDOM V

Family 5. Const ellariidae. Ulrich.

Zoaria ramose, frondescent, laminar, or encrusting. Zoos^ial tubes thin-walled and
prismatic in the axial region, thicker and sub-cylindrical in the peripheral; apertures
rounded, the peristomes slightly elevated. Mesopores angular, abundant, generally isolating
the zocecia, at intervals gathered into usually stellate clusters; closed at the surface, the
closure with numerous perforations. True acanthopores wanting, but small hollow spines
or granules often very abundant. Diaphragms straight and complete in both sets of tubes.
Ordovician and Silurian.

Constellaria, Dana (Fig. 461). Zoaria growing erect from a basal expansion which
is attached to foreign bodies. Surface with depressed stellate maculae, the spaces
between the rays elevated and occupied by two or three short rows or clusters of

FIG. 461.

tial, showing aged condition.

Constellaria florida, Ulr. Cincinnati, O. A, Vertical section. B, Tangentia
C, Average tangential section, all 14/1- D, Branch of the natural size (after Ulrich).

closely approximated zocecial apertures. Mesopores aggregated in the maculae, inter-
nally with gradually crowding diaphragms. Ordovician.

SteUipora, Hall (non Hagw. nee Haime). Differs from the above in its encrusting
habit, and in having only mesopores in interspaces between the raised zooscial clusters.
Ordovician.

Nicholsonella, Ulrich (Fig. 462). Laminar expansions, sometimes giving off
flattened, intertwining branches or fronds. Interzooscial spaces wide, and with

Fio. 4(32.

Nicholsonella pulchra, Ulr. Lower Trenton ; Tennessee. A. Surface. 7/i. B, Vertical section,
gential sections at different levels, M/J (after Ulrich).

C, Tan-

numerous mesopores, which have thicker and more numerous diaphragms than the
zorccial tubes ; the spaces become filled up with age by a calcareous deposit, rendering
walls of mesopores unrecognisable. Ordovician.

Idiotrypa, Ulrich ; (?) Dittopora, Dybowski. Silurian.

SUB-OHM.K II

TREPOSTOMATA

277

Family 0. Batostomellidae. Ulrich.

ramose, occasionally sub-lolate, massive, laminar, or parasitic, often
consisting of superimposed layers. Zocecia with thick uv///.< in H" ///"'«/• rtffion, </.</></////

,!,,/„ nrinii here as fn*<l.

those in pei'ij>li>i'nl

central perforation.

1 1 til/ IIUKII-

/nirr.< n.<ii<iHii fin* at ; tin-
Intt.r tin, ill, './'/.// ////./•-

-initt'iit. Ordovician to
Permian.

Bythopora, Miller
ami Dyer. Small
branching stems. Aper-

Fio. 463.

Ulr. Chester Group; Kentucky. A, B, Vertical
sections, one with and the other without diaphragms, u/i. C, Tangential

tures oblique attenuate se<-'t'u". 14/i- />, Surface, 14/i. On either side of C are branches of the natural

above. Interspaces

canaliculate, with an occasional mesopore or none. Ordovician.

Callotrypa, Hall ; Silurian. Eridotrypa, Ulrich ; Ordovician to Devonian.

A TJ Batostomella, Ulrich (Geinit-

zella, W. and W. ; Trematella,
Hall), (Fig. 463). Slender
branches, without monticules.
Apertures small, circular, or oval.
Interspaces rounded or canal-
iculate, spinulose, the acantho-
pores small and usually very
numerous. Mesopores small,
sub-circular. Diaphragms few.
Devonian to Permian.

Stenopora, Lonsd. (Fig. 464).
Zoaria ramose, sub-lobate, massi ve,
laminar, or parasitic. Surface
Zocecial walls periodically thickened in the mature region.

Fio. 464.

>y. //c/xi;-,; mill rii-inut, Ulr. Keokuk Group; Illinois. Vertical
(X)and tangential (/.') sections showing nioniliform walls and per-
forated diaphragms, i*/i (after Ulrich).

even or montiferous.
Large acanthopores at many
of the angles between the
zooecia. Mesopores never
very numerous, irregularly
distributed. Diaphragms
sometimes very scarce, but
in most American species
abundant in the peri ]>li era 1
region, and with a large
central perforation. Sub-
Carboniferous to Coal
Measures.

Anitotrypa, Ulrich.
Divisional line between ad-
joining tubes more sharply

defined, and periodic swellings of the walls much less distinct than in Stenopora. Acan-
thopores and mesopores absent ; perforated diaphragms numerous. Sub-Carboniferous.

? Lioclema, Ulrich (Fig. 465). Ordovician to Sub-Carboniferous.

Fio. 465.

Liockma foliata, Ulr. Keokuk Group; Illinois. A, Vertical section,
.ngential section, '^/i- C, Portion of wall and acanthopore, ^/i

278

MOLLUSCOIDEA— BRYOZOA

SUB-KINGDOM v

Family 7. Amplexoporidae. Ulrich.

Zoaria ramose, encrusting, discoidal, or 'massive, rarely bifoliate. Zocecial tubes com-
paratively simple, prismatic, with a well-marked divisional line between adjoining tubes.
Mesopores practically absent, but small abortive cells sometimes found among the large
zoozcia forming the monticules. Acanthopores generally abundant, sometimes wanting.
Ordovician to Devonian.

Amplexopora, Ulrich. Zoaria ramose. Acanthopores always present, varying

in size and number. Diaphragms
complete, horizontal. Ordovician to
Devonian.

Monotrypella, Ulrich. Like the
above, but without acanthopores. Ordo-
vician to Devonian.

Petalotrypa, Leptotrypa, and Discotrypa,
Ulrich. Ordovician to Devonian.

Atactopora, Ulrich (Fig. 466). Zoaria
thin, growing on Orthoceras. Zooscial
apertures indented or floriform, accord-
ing to position of the very numerous acanthopores. Rather large, solid elevations,
composed of abortive cells, and completely filled by calcareous deposit, stud the surface
at regular intervals. Diaphragms thin, few, sometimes wanting. Ordovician.

FIG. 466.
Atactopora maculata, Ulr. Cincinnati, O. Transverse

Sub-Order C. CEYPTOSTOMATA. Vine.

Primitive zocecium short, pyriform to oblong, quadrate, or hexagonal, sometimes tubular,
the aperture anterior. In the m,ature colony the aperture is concealed, occurring at the
bottom of a tubular shaft (" vestibule "), which may be intersected by straight diaphragms or
hemisepta, owing to the direct superimposition of layers of polypides. Vestibular shaft
surrounded by vesicular tissue, or by a solid calcareous deposit ; the external orifice rounded.
and avicularia wanting.

The Cryptostomata differ from the Trepostomata chiefly in that the "immature region"
(primitive cell) is usually much shorter, and the passage to the mature region more abrupt.

Some of the Cryptostomata are ramose, and have long, thin- walled prismatic tubes in the
axial region, with or without diaphragms, precisely as in the ramose Trepostomata and Cyclo-
stomata ; but they are distinguished from the latter by the presence of hemisepta, similar to
those occurring in the vestibule of Escharopora and Phaenopora, two of the most typical genera
of the Cryptostomata. That these axial tubes are not of primary importance is shown by such
genera as Coelocomis, fihombopora, etc., in whose axial tubes a second layer of zooecia has
grown over the first. This is a rare condition, and is probably to be attributed to an accidental
interruption of growth. But, where observable, it is to be noticed that the inner extremities
of the zooecia of the second layer are not drawn out into tubes like those of the primary set,
but are short, and in all essential respects like those of Escharopora.1

The Cryptostomata are probably nothing more than Palaeozoic Chilostomata, differing,
however, from the typical members of the latter (1) in having neither marsupia nor avicularia ;
(2) in the much greater deposit of calcareous matter upon the front of the zocecia, thus
producing the vestibule ; (3) in that successive layers of polypides are often developed, one
directly over the other, in a continuous tube ; and (4) in that whenever a zoarium attains an
uninterrupted width of more than 8 mm., it exhibits clusters of cells differing more or less,
either in size or elevation, from the average zooecia. The last two distinctions are suggestive
of the Trepostomata ; and the presence of a vestibule reminds us of certain Mesozoic and recent

1 [The almost universal practice lias been to accept the presence of tubular zocecia as fully
demonstrating the Cyclostomatous affinities of the species producing them. Recent investigations,
however, show that the mere form of the zorecium cannot be relied upon as a subordinal character
any more than is the presence of tabulae in a tubular organism a certain indication of an
Anthozoan.]

SUB-ORDER c CRYPTOSTOM AT A 279

r/n'/nstamata, which have the same tubular prolongation of tlie aperture. Thus, the recent
A'i> on- f/it "//"/'//<•", Busk, has not only a vestibule, but hemisepta as well. Hemisepta are
nevei found in tin- <';/<•/< istmiuita and Trepostomata, but are a very common feature of the
rritfifiixti'iH'if't. They occur at the bottom of the vestibule, and doubtless served as supports
for the movable operculum.

Family 1. Ptilodictyonidae. Ulrich.

Zoaria bifoliate, composed of two layers of zocecia grown together back to back, con-
tinuous or joint' <l, n,,,] fumiinii l«if-like expansions, or compressed, branching, or inosculating
stems. Mesial plates 'without median tubuli ; hemisepta usually present. Inner orifice
•i> //• mil if * nii-i/lijitii-nl, the outer more rounded, usually ovate, and surrounded by either a
.<loj>in<l area or a ring-like peristome. Vestibules separated by thick walls. Ordovician to
Sub-Carboniferous.

Ptilodictya, Lonsd. (Heterodictya, Nich.) Zoaria simple, unbranched, lanceolate,
or falciform, with a small basal expansion. In the young condition the zoarium
consists of longitudinally arranged, narrow, oblong-quadrate zoo3cia, new zooecia, of
different width and arrangement, being added subsequently on each side. In the
vestibular or outer region the walls are more or less thickened, solid, and with a
double row of exceedingly minute dots. Ordovician to Devonian.

Escharopora, Hall (Nicholsonia, Waag. and Wentz). Distinguished from the last
chiefly by the arrangement of the zocecial apertures, which are in diagonally inter-
secting series, and by the hexagonal sloping area which surrounds the external orifice.
Ordovician.

Clathropora, Hall. Zoaria composed of anastomosing branches forming a regular
network with round fenestrules, terminating below in a pointed, articulating base.
Zooecial apertures usually sub - quadrate, arranged longitudinally. Ordovician to
Devonian.

Phaenopora, Hall. Zoaria as in Ptilodictya, except that there are two mesopores
in each interspace between the ends of the zoo2cial apertures. Ordovician and
Silurian.

Arthropora, Ulrich. Zoaria bushy, spreading in a plane, composed of numerous
equal segments. Zooecial apertures elliptical, surrounded by a delicate peristome.
Interspaces with one or more threadlike ridges, variously disposed, and with a row
of minute papillae. Ordovician.

Graptodictya, Ptilotrypa, Ulrich ; Ordovician. Taeniodictya, Ulrich ; Devonian
and Sub-Carboniferous.

Stictotrypa, Ulrich. Brandies not jointed at the base. Zooecial apertures
circular or elliptical, with a distinct, evenly elevated peristome. Ordovician and
Silurian.

Stictoporella, Ulrich. Zoaria variously formed, with elliptical apertures placed at
the bottom of a sloping area. Thick-walled, untabulated mesopores occur between
the zocecial apertures and line the zoarial margins. Ordovician to Sub-Carboniferous.

Intrapora, Coscinella, Hall. Devonian.

Family 2. Bhinidictyonidae. Ulrich.

Zoaria bifoliate, continuous or jointed, forming compressed branches or leaf-like expan-
sions ; occasionally trifoliate. Primitive cells sub-quadrate, arranged longitudinally. Both
primitive and superficial apertures elliptical or sub-circular, sometimes a little truncated
posteriorly. Inferior hemiseptum and lunarium wanting. Median tubuli present between
the median laminae, and between the longitudinal rows of zocecial tubes. Mesopores absent,
but vesicular tissue often present. Chiefly Ordovician.

Rhinidictya, Ulrich (Stictopora, Ulrich 11011 Hall). Zoaria composed of narrow,

280 MOLLUSCOIDEA— BRYOZOA SUB-KINGDOM v

compressed, dichotomously dividing, straight-edged branches, attached to foreign bodies
by a continuous expanded base. Ordovician and Silurian.

Eurydictya, Dicranopora, Goniotrypa, Ulrich. Ordovician.

Euspilopora, Ulrich. Small, irregularly divided branches, with serrated or wavy
edges. Devonian.

Phyllodictya, Ulrich. Zocecial tubes long, with complete diaphragms, but no
hemisepta. ' Ordovician.

Pachydictya, Trigonodictya, Ulrich. Ordovician and Silurian.

Family 3. Cystodictyonidae. Ulrich.

Zoaria consisting of two or three layers of cells grown together back to back, forming
branching, perforated, or entire leaf-like expansions, or triangular branches. Primitive
cells semi-cordate or obovate-acuminate in outline, arranged longitudinally. Primitive
aperture sub-circular, but becoming drawn out into a tubular vestibule as growth proceeds.
Superficial aperture with peristome, and more or less well-developed lunarium. Interzocecial
spaces occupied by vesicular tissue, often filled with a calcareous deposit near the surface.
Silurian to Carboniferous.

Cystodictya, Ulrich. Zoaria ramose, branches sharply elliptical, with sub-parallel,
non-poriferous margins. Interapertural spaces finely striated, granulose or smooth ;
pits and cells showing only in a worn condition. Silurian to Carboniferous.

Coscinium, Keyser (Coscinotrypa, Hall) ; Dichotrypa, Ulrich. Silurian to Car-
boniferous.

Taeniopora, Nich. Distinguished from Cystodictya by having a longitudinal ridge
or keel, which divides each face into two equal parts. Devonian.

Prismopora, Scalaripora, Hall. Devonian.

Evactinopora, Meek and Worth. Zoaria free, consisting of four or more vertical
leaves arranged in a stellate or cruciform fashion. Sub-Carboniferous.

Glyptopora, Ulrich. Zoaria consisting of thin expansions traversed on both surfaces
by salient ridges, or of uni-laminate bases on which the coalescing ridges of the upper
surface are greatly developed and form large leaves. These ridges or leaves are
composed of two layers of cells growing in opposite directions from a mesial lamina.
Upper surface with solid maculae or " dimples." Sub-Carboniferous.

Rhinopora, Hall. Zoaria forming large undulating expansions, the free margins
thickened or sharp and non-poriferous. Surface without maculae or monticules, but
exhibiting thread-like bifurcating ridges, which appear as shallow grooves when the
surface is worn. Large median tubuli between the mesial laminae. Silurian.

Family 4. Arthrostylidae. Ulrich.

Zoaria articulated, consisting of numerous sub-cylindrical segments united into small
pinnate or bushy colonies, or of continuous, dichotomously divided branches. Zooscia sub-
tubular, more or less oblique, radially arranged about a central axis, and opening on all
sides of the segments; or one side may be non-celluliferous and longitudinally striated.
Ordovician and Silurian.

Arthrostylus, Ulrich. Zoaria bushy, dichotomously branching, the whole consisting
of numerous exceedingly slender, equal, sub-quadrate segments, united by terminal
articulation. Zocecia usually arranged in three rows between longitudinal ridges ; the
fourth face with longitudinal striae only. Ordovician.

Helopora, Hall. Like the preceding, but the segments are larger, and have
zoo3cial apertures on all sides. Ordovician and Silurian.

SUB-ORDER c CRYPTOSTOMATA 28 1

Sceptropora, Ulricli. Segments short, greatly expanded above, celluliferous all
around. Ordovician and Silurian.

Arthroclema, Bill. Segments sub-cylindrical, celluliferous on all sides, arranged
pinnately. Articulation both terminal and lateral. Ordovician.

Nematopora, Ulrich. Xi.ari.-i very slender, ramose, continuous above the pointed
basal extremity. Zocecia sub-tubular, arranged radially about one or two minute axial
tubes. Ordovician and Silurian.

Family f>. Rhabdomesodontidae. Vine.

Zoaria ramose or simple, not articulated, sometimes with a large or small axial tube,
and generally solid. In the latter case the axial region is occupied by thin-walled primitive
tubes, with or without diaphragms. Hemisepta usually present, but never conspicuous.
External zocecial apertures oval or circular, regularly arranged, and usually at the bottom
of a rhombic or hexagonal sloping area, or between longitudinal ridges. Mesopores absent.
Silurian to Carboniferous.

Rhombopora, Meek (Orthopora, Hall). Zoaria slender, ramose, solid. Zocecial tubes
with the outer or vestibular region thick-walled, apertures arranged in diagonal or
longitudinal lines. Strong acanthopores and smaller spines generally present. Silurian
to Carboniferous.

Bactropora, Hall. Zoaria simple or only slightly branched, the lower extremity
pointed. Sub-Carboniferous.

Ehabdomeson, Young. Differs from Bhombopora only in having a slender axial
tube, to which the proximal ends of the zooecia are attached. Carboniferous.

•Goeloconus, Ulrich. Zoaria simple, hollow, expanding gradually from the striated
base ; substance thin. Primitive portion of zocecia short, with well-developed hemi-
septa. Sub-Carboniferous.

? Tropidopora, Hall ; Devonian. (?) Streblotnjpa, Ulrich ; Devonian and Sub-
Carboniferous.

Family 6. Fenestellidae. King.

Zoaria forming reticulate expansions, celluliferous on one side only. They are composed
of rigid branches united by regular non-poriferous bars (dissepiments] • or may be sinuous
and anastomose at regular intervals ; or may remain free. Zooecia enclosed in a calcareous
crust, ivhich is minutely porous, especially on the non-celluliferous side. Primitive portion
of zooecia oblong, quadrate, or hexagonal in outline. Superior hemiseptum usually present,
the inferior one less frequently. Primary orifice anterior, semi-elliptical, truncated behind.
External apertures rounded, with peristome, and covered, when perfect, by centrally perforated
closures. Ordovician to Permian.

The zoarial characters of the Fenestellidae are extremely constant, and are of the greatest
systematic importance. The xocecial cavity in this family is very similar to that of the Ptilo-
dictyonidae and Ehinidictyonidae ; and the same is also true of both the primary and external
orifices. Ulrich considers the family as having been derived from Phylloporina.

Fenestella, Lonsd. (Fenestrella, d'Orb. ; Actinostoma, Young), (Fig. 467). Zoaria
flabellate or funnel-shaped, poriferous on the inner side. Branches generally straight,
sometimes flexuous, connected at regular intervals by dissepiments. Zorccia in two
rows, separated by a plain or tuberculose median keel. Ordovician to Permian ;
chiefly Devonian and Sub- Carboniferous.

Semicosminium, Prout ^Carinopora, Nich.) Zoaria funnel-shaped, poriferous on
the outer side. Dissepiments wide, very short, the branches appearing to anastomose
on the non-poriferous face, where the fenestrules are sub-rhomboid al or rounded.
Zocecia in two ranges, median keel very high and expanded at the summit. Silurian
and Devonian.

282

MOLLUSCOIDEA— BKYOZOA

SUB-KINGDOM V

Fenestropora, Hall. Like the preceding, except that the reverse of the zoarium
and the expanded summits of the carinae bear large, scattered pores or pits. Devonian.

Isotrypa, Loculipora, Unitrypa, Hall. Silurian and Devonian.

Hemitrypa, Phill. Differs from Fenestella in having a reticulated superstructure,
whose meshes correspond in position and number with the zocecial apertures in the

FIG. 467.

Fenestella retiformis, Schloth. Permian Dolomite ; Possneck, Thuringia. A, Fragment of zoarium, natural
size. B, Portion of external surface, slightly enlarged. C, Magnified portion of interior celluliferous surface.

branches beneath. The structure rests on pillars which rise at regular intervals from
the moderate median keel of the branches. Silurian and Devonian. x

Helicopora, Claypole. Zoaria spiral, the inner edge thickened and non-poriferous,
but not forming a solid axis. Otherwise like Fenestella. Silurian, (?) Devonian.

Archimedes, Lesueur (Fig. 468). Distinguished from Helicopora by its solid central

FIG. 468.

Archimedes Wortheni, Hall sp. Sub-Carboniferous; Warsaw, 111. A, Fragment of well-preserved zoarium,
Vi (after Roemer). B, Broken spiral zoarium (after Quenstedt). C, Portion of interior or upper surface of the
expansion, enlarged (after Roemer). D, External or inferior aspect of same (after Hall).

axis. As a rule, the fenestrated expansion is broken away, leaving only the screw-like
axis. Sub- Carboniferous.

Lyropora, Hall. Zoaria flabellate, the fenestrated portion spread between the arms
of a non -celluliferous U- or V-shaped support ; free or pedunculate at the base.
Zocecia in from two to five rows. Sub-Carboniferous.

Fenestralia, Prout. Having a median keel as in Fenestella, but with four ranges of
zocecia instead of two. Sub-Carboniferous (St. Louis Group).

Polypora, M'Coy. Differs from Fenestella in having two to eight rows of cells on a
branch, and in wanting a median keel. The latter is sometimes represented by a row
of strong tubercles. Silurian to Carboniferous.

SUB-ORDER C

CRYPTOSTOMATA

283

Thamniscus, King. Like Polypora, but branches bifurcating more freely, and with
only a few dissepiments or none. Silurian to Permian.

Phyllopora, King. Zoaria lunm-Miaped, celluliferous on the outer side, and con-
sisting of anastomosing branches, \\lii.h form a regular, round -meshed network.
Zoojcia in two or more rows. Devonian and Permian.

Ptiloporella, Ptiloporina, Hall. Silurian and Devonian.

Ptilopora, M'Coy (Dendricopora, de Kon.) Zoaria pinnate, the central branch much
stronger than the oblique lateral branches, which are united by dissepiments. Zoo2cia
in two ranges. Devonian and Sub-Carboniferous.

Family 7. Acanthocladiidae. Zittel.

Zoaria poriferous on one side only, pinnate or forming fenestrated expansion ; consisting
of strong, central stems which (jive off numerous, smaller, lateral branches from their opposite
maryins. The lateral branches are free or unite with those of the next stem. Non-
poriferous dissepiments absent. Zocecial characters mostly as in the Fenestellidae. Silurian
to Permian.

J'tunatopora, Vine (Glauconeme, auct.) Zoaria small, delicate, with short, free,
lateral branches given off frequently at regular intervals. Cells in two rows, one on
each side of a moderate median keel.
Silurian to Carboniferous.

Septopora, Prout. Zoaria fenes-
trated, flabellate, or leaf-like. Primary
branches numerous, increasing by bi-
furcation or interpolation ; the lateral
branches uniting with those of adjacent
stems. Reverse usually with fine striae
and scattered dimorphic pores. Cellu-
liferous side with two rows of zocecia
arranged as in Pinnatopora. Chester
Group and Coal Measures.

Acanthocladia, King. Like Pin nato-
pora, but larger, stronger, and with
three or more ranges of cells. Coal
Measures and Permian.

Synocladia, King. Differs • from Septopora in the same manner as the preceding
differs from Pinnatopora. Permian.

Diplopora, Young. Essentially a Pinnatopora without lateral branchlets. Carboni-
ferous.

Ichthyorachis, M'Coy, Penniretepora, d'Orb., and Ramipora, Toula, may belong here.

FIG. 469.

Hdopora spiniformis, Ulr.
Tn-nton; Tennessee. A, Ver-
tical section, 1%. Ji, Segment,
Vl and 14/j (after Ulrich).

Fio. 470.

Pachydictya foliata,
Ulr. Lower Trenton ;
Minnesota. Tangential
section, u/i (after
Ulrich).

Family 8. Phylloporinidae. Ulrich.

Zoaria branching, celluliferous on one side only, the other side striated ; branches free or
anastomosing. Zocecia more or less tubular, often with diaphragms. Hemisepta wanting.
Ordovician to Coal Measures.

Phylloporina, Ulrich. Branches irregularly anastomosing, with two to eight
ranges of zooecia on the celluliferous side. Tabulated interstitial spaces generally
present, closed at the surface. Ordovician and Silurian.

Drymotrypa, Ulrich ; Ordovician and Silurian. Chainodictyon, Foerste ; Coal
Measures.

The following genera of doubtful affinities may be provisionally appended here :— -
Proutella, Cycloporella, Worthenopora, Ulrich ; Cyclopora, Prout ; Paleschara, Hall.

284

MOLLUSCOIDEA— BRYOZOA

SUB-KINGDOM V

Sub-Order D. CHILOSTOMATA. Busk.

(Bryozoaires cellulines, d'Orbigny.)

Zooecia oval, turbinate, urceolate, quadrate, or hexagonal, arranged usually side by
side. Orifice more or less anterior, of smaller diameter than the zocecium, closed by a
movable cover. Ova commonly matured in external marsupia. Appendicular organs
d.

True Chilostomata are first met with in the Jura, but their progenitors are undoubtedly to
be looked for in the Palaeozoic Cryptostomata. They attain an astonishing development in the
Upper Cretaceous, and in the Tertiaries and existing seas they greatly surpass the Cyclostomata
in number and variety of species.

Not all of the Chilostomata have a completely calcified zoarium, some being corneous and
flexible (Flustridae), and others having the front wall of the zocecia more or less membraneous
and the rest calcareous (Membraniporidae). Consequently, in fossil examples of the latter, the
zooecia are entirely open on the upper or front side (Fig. 477). Avicularia and vibracula are
very commonly present, and are indicated in fossils by the " special pores " in which they were
lodged. External ovicells are more commonly developed than in the Cyclostomata, and usually
occur as rounded, blister -like cavities in front of the zooecial apertures. Reproduction by
gemmation takes place at the growing edge of the colony, the young cells arising from the
anterior end or from either side of the parent cell ; and repeated gemmation almost always
results in a more or less regular arrangement in series. Direct communication between adjoining
zooecia is effected by means of small perforated plates (communication plates, Roscttenplatteri),
set in corresponding positions in the side walls of each zooecium.

The classification of the Chilostomata is as yet in an unsettled condition. The older systems
of d'Orbigny and Busk were highly artificial, undue prominence having been given to zoarial
modifications ; but through the labours of Smitt, Hincks, and Waters, who have demonstrated

the much greater importance of
zocecial characters, a decided advance
lias been made. Only brief descriptions
of the more important genera, or those
having numerous fossil representatives,
can be introduced here.

Family 1. Eucrateidae. Busk.

Zoaria branching, erect, and free,
or recumbent. Zocecia uniserial or
biserial, pyriform, with a sub-terminal
and usually oblique aperture. Avicu-
larian and vibracular appendages
wanting. Cretaceous to Recent.

Eucratea, Lamx. (Fig. 471). Zoaria entirely decumbent, or composed of a
creeping, adherent base and erect branching shoots. Zooecia calcareous or sub-
calcareous, rising one from another so as to form single series. Branches springing
from the front of a zocecium below the aperture.

FIG. 471.

Eucratea, labiata, Novak sp. Cenomanian ; Velim, Bohemia.
A, Zoarium, Vi- -B> Zooecia, three of them with fractured walls,
highly magnified (after Novak).

Family 2. Cellulariidae. Busk.

Zoarium erect, usually jointed, dichotomously branching, phytoid. Zooecia in two or
more series, closely united and arranged in the same plane. Sessile avicularia and
vibracula generally present. Tertiary and Recent.

Cellularia, Pallas ; Menipea, Caberea, Lamx. ; Scrupocellaria, Van Benecl. Miocene
to Recent.

CHILOSTOMATA

285

Family 3. G-emellariidae. Busk.

Z'xiriuni *tth-,-«lciir«'ii*, .flexible, continuous. Zocecia somewhat obconical, opposite,

In y «//Yx, inmnnnl. KYrriit.

Gemellaria, Savigny ; Scruparia, Hincks ; Notamia, Fleming.

Family 4. Cellariidae. Hincks (Salicornariadae, Busk)

Zoarium erect, *iil>-<-iili',iilri<-nl, < I ichotomously branching, usually
jointed. Zocecia rhomboidal or hexagonal, each corresponding to an
area, and disposed in series about an imaginary axis ; front depressed,
usually concave. Orifice crescentic or semi-circular, situated slightly
above the centre of the cell. Ocecia inconspicuous, opening at or near
the summit of the area above the orifice. Avicularia usually present.
Cretaceous to Recent.

Cellaria, Lam. (Salicornaria, Cuv. ; Salicornia, Schweigg), (Fig.
472). Zoarium jointed, the segments sub-cylindrical and connected by
flexible, horny tubes. Zooecia immersed, surrounded by a raised

border disposed in quincunx. Avicularia irregularly distributed, Goidf.sp. oiigocene;

.11. Kaufungen, near

situated above a cell, or occupying the place ot one. Cassei. Enlarged

FIG. 472.
Cellaria rhombifera,

(after Reuss).

Family 5. Selenariidae. Busk.

Zoaria circular or irregular in outline, the celluliferous side convex, the lower concave or
fiat, probably free in the mature condition. Upper surface areolated, the zocscia immersed,

KM;. 473.

I.nniii;tfs HoliJfits*;, Ha^w. Upper Cretaceous, Liineburg. a-c, Zoarium of the natural size; d, Upper sur-
face, enlarged ; <-, LMWIT surface, enlarged.

their borders elevated. Orifice rounded or semi-elliptical, situated more or less in advance
of the depressed front. Small vibracular cells usually present. Cretaceous to Recent.

Lunulites, Lamx. (Fig. 473). Zocecia arranged in series radiating from the centre
and bifurcating as they advance toward the border. Vibracular cells usually elongate,
lying in linear series between the rows of zocecia. Very abundant in the Upper
Cretaceous and Tertiary ; also Recent.

SticJiopora, Hagw. emend. Busk. Vibracular cells wanting. Zocecia equal, hexa-
gonal, not arranged in radiating series. Cretaceous.

Selenaria, Busk. Cretaceous to Recent.

286

MOLLUSCOIDEA— BRYOZOA

SUB -KINGDOM V

Family 6. Onychocellidae. Jullien, emend.

Zoaria encrusting or erect, ramose, continuous, the branches more or less compressed and
bilaminar ; surface areolated. Zocecia usually hexagonal, their margins raised, the front
not entirely calcified. Opesial aperture of moderate size, generally semi-elliptical, sometimes
spreading below, in other cases sub-circular. Oral opening small, usually crescentic or semi-
circular. Ooecia inconspicu-
ous ; intercalated vicarious
avicularia generally present ;
special pores wanting. Cre-
taceous to Recent ; chiefly
Cretaceous.

According as the specimens
were encrusting or erect, they
have been called Cellepora and
Membranipora ; or by others,

vS^fflTll i|J^lfff^^ andS^s^r'S^ed^ccid-

. A a a A * . I ing to Waters and others, all
of these names have boen
applied to a single species.
Onychocella angulosa, Reuss
sp. The zocecial characters
are comparatively simple and
uniform, and in most cases '
the same as in the Cellariidae.

On the other hand, species having a larger opesial opening than usual (Vilracella, etc.) evince
a decided resemblance to certain of the Membraniporidae. The systematic position of the
family therefore appeal's to be intermediate between the Cellariidae and Membraniporidae.
The relations of this family with the Palaeozoic Cryptostomata and Trepostomata are worthy of
further investigation.

Onychocella (Jullien), Waters (Eschara, Flustrellaria, p.p., d'Orb. ; Cellepora,
i, Vincularia, etc., auct,), (Fig. 474). Zoaria encrusting or erect. Oral

Onychocella

Reuss sp.
Upper Eocene;
Northern Italy.
Surface, ao/j (after
Waters).

Vincularia virgo, Hagw. Upper
Riigen. a, Portion of zoariuin, i/l
section ; c, Vertical section, enlarged.

Cretaceous

FIG. 476.

Cumiilipora angulata, Miinst. Oligocene ; Doberg, near Blinde. A, Zoarium, natural size. B, Upper surface,
enlarged. C, Vertical section, enlarged (after Reuss).

opening semi-circular or crescentic. Avicularian openings simple, oval ; the area in
which they are situated drawn out above. Cretaceous to Recent.

Vibracella, Waters (Flustrellaria, p.p., d'Orb.) Differs from Onychocella in having
a larger aperture, which is often somewhat expanded below, and having vibracular
cells instead of avicularia. Cretaceous and Tertiary.

1 Oumulipora, Miinst (Fig. 476). Zoaria irregularly massive. Zooecia partly
recumbent, partly erect, and placed one above the other, so that they appear to form
tabulated tubes. Tertiary.

SUB-ORDER D

CHILOSTOMATA

287

Family 7. Membraniporidae. Busk.

Zoarium calcareous or membrano-calcareous, encrusting or erect, in the latter case bifoliate,
or sub-cylindrical. Zooecia placed side by side, and forming an irregular continuous-
expansion, or in linear series. Margins raised, the depressed front more or less
membraneous. Cretaceous to Recent.

Membranipora, Blainv. (1 Marginaria, Roemer ; (?) Dennatopora, Hagw.), (Fig*. 477,
478). Zoaria encrust in-, « alcareous, or sub-calcareous. Zooecia arranged irregularly or
in rows, without a calcareous lamina on the front, or only partially covered by one,
leaving a variously shaped aperture.

Family 8. Cribrilinidae. Hincks.

Zoaria encrusting or erect. Zooecia having the front wall more or less fissured, or
traversed by radiating furrows. Cretaceous to Recent.

Membraniporella, Smitt (Fig. 479). Zoaria encrusting or rising into free foliaceous

LM jjjj

'•^t ^^aR^

FIG. 479.

FIG. 480.

FIG. 478.

FIG. 477.

Encrusting /uui'ium of Membranipora,
with non - calcified zooecial walls.
Magnified.

Membraniporella

Abbotti, G. and H.

sp. Cretaceous ;

N.J. Zocecia highly

highly magnified (after magnified (after magnified (after
Uibb'an.l Horn). Gabb and Horn). Gabb and Horn).

Membranipora plebeia,
G. and H. Cretaceous ;
N. J. Several cells

Cribrilina Heer-
manni, G. and H.
sp. Post-Pliocene ;
Santa Barbara Co.,
Cal. Zocecia highly

expansions, sometimes consisting of superimposed layers. Zocecia closed in front by
a number of flattened calcareous ribs more or less consolidated
centrally. Cretaceous to Recent.

Cribrilina, Gray (Fig. 480). Zoaria usually encrusting. Zooecia
having the front more or less occupied by radiating or transverse
rows of punctures, each row in a furrow ; orifice semi-circular or
sub-orbicular. Cretaceous to Recent.

Family 9. Microporidae. Smitt.

Zocecia having the front wall entirely calcareous; usually with
short, elevated margins, fissures, or perforations. Cretaceous to Recent.

Micropora, Gray (Fig. 481). Zoaria encrusting. Zooecia with
prominent raised margins ; the front depressed, with a perforation highly
at each upper angle below the semi -circular or rounded orifice. Horn).
Cretaceous to Recent,

Steganoporella, Smitt ; Setosella, Hincks. Recent.

FIG. 481.

Micropora disparilis,
G. and H. sp. Post-
Pliocene ; Santa Bar-
bara Co., Cal. Zouvi;i
magnified
Gabb and-

288 MOLLUSCOIDEA— BRYOZOA SUB-KINGDOM v

Family 10. Microporellidae. Hincks.

»

Zoaria encrusting or erect, foliated or dendroid. Zocecial orifice more or less semi-
circular, with the lower margin entire; a crescentic or
circular pore on the front wall usually just beneath the
orifice. Cretaceous to Recent.

Microporella, Hincks (Fig. 482). Zoarium encrusting
or erect, bilaminar. Margin of zooecia not elevated.
Orifice with a straight, entire lower border, frequently
with oval spines. Usually one semi-lunate or circular
pore beneath the orifice, occasionally two or three.
Tertiary and Recent.

Diporula, Chorizopora, Hincks. Tertiary and Recent.

? Monoporella, Hincks. Like Microporella, but with-
out special pores. Cretaceous to Recent.

Microporella riuJis, Reuss sp. _ .,

oiigocene; Soiiingen. Upper sur- family 11. Porimdae. d Orbigny, emend. Hincks.

face, enlarged.

Zoaria encrusting, or erect and ramified. Zooecia with

a raised tubular or sub-tubular orifice, and frequently with a special pore on the front wall.
Cretaceous to Recent.

Porina, d'Orb. Zoaria consisting of flattened or sub-cylindrical branches, celluli-
ferous on both sides, or encrusting. With age the spaces between the raised apertures
become filled with a porous calcareous deposit. Avicularia and ooecia occasionally
•distinguishable. Cretaceous to Recent.

Celleporella, Gray ; Anarthropora, Smitt ; Lagenipora, Hincks. Recent.

Family 12. Escharidae. Hincks.

Zoaria erect, unilaminate or bilaminate, foliaceous or ramose, or crustaceous, loosely
attached or adnate. Zoozcia urceolate, the front entirely calcified, without raised margins.
Orifice anterior, sub-circular to horseshoe-shaped, the lower border straight, broadly sinuate, or
notched. An elevated secondary orifice, with the lower margin dentate, channeled, or
enclosing an avicularium, often present, but no special pores. Cretaceous to Recent.

This family embraces a large number of fossil and existing Bryozoans, and in its present
state can hardly be said to form a natural group. It is here that the much greater importance
of zocecial characters as compared with zoarial are particularly apparent ; inasmuch as one genus,

or n many cases a species, as now generally understood, may include a considerable range of
zoarial types. To the palaeontologist the group offers exceptional difficulties, since generic
characters frequently depend upon easily abraded or obscure modifications of the orifice.

Lepralia, Johnston (Fig. 483). Zoaria encrusting or rising into simple or branching
expansions, composed of one or two layers of cells. Zooecia usually ovate, the orifice
with a thin peristome and entire lower margin. Rare in Cretaceous, more abundant
in Tertiary and Recent.

Porella, Gray. Zoaria encrusting or erect. Zooecia with a semi-circular primary
orifice ; the secondary (adult) orifice elongate, inversely sub-triangular, or horseshoe-
.shaped, and enclosing an avicularium with a rounded or sub-triangular mandible.
Tertiary and Recent.

Smittia, Hincks. Zoaria encrusting, or erect and foliaceous. Primary orifice of
zooecia sub-orbicular, the lower margin with an internal median denticle. Secondary
orifice canaliculate below ; generally a small avicularium either within or just beneath
the sinus. Miocene and Recent.

Mucronella, Hincks (Fig. 484). Similar to Smittia, but with simpler orifice, and

si T.-oHDER D

CHILOSTOMATA

tin- lower part of the peristome elevated into a more or less prominent mucro. Tertiary
oent

>v//r.ny ,.,,,//,,, Ilinrks. Zoaria variable; zooecial orifice varying from semi-circular
t.i Mil.-orbicular, tin- lowi-r margin with ;i di.-tinct sinus. Cretaceous to Recent.

FIG. 483.

Lepralia pallasiana, Moll.
i'i-ciit ; England.

highly
Hincks).

nagnified

Zooecia
(after

Fio. 484.

Mucronell'i cocci net',
Abildg. Miocene; Eisen-
stadt, Hungary. A num-
ber of zocecia enlarged
(after Reuss). The aper-
tures are denticulated,
and each zooecium has a
pair of avicularia. o.
Ovicell.

Fio. 485.

Schizoporella cum nt»,
G. and H. sp.
Pliocene ; Santa Bar-
bara Co., Cal. Zooecia
highly magnified
(after Gabb and
Horn).

Retepora, Imperato (Phidolophora, Gabb and Horn), (Fig. 486). Zoaria consisting
usually of inosculating branches which spring from an encrusting base. Zooecia dis-
posed on one face of the branches only, in most cases immersed. Primary orifice
rounded or semi-elliptical with entire border. Afterwards the peristome becomes much

FIG. 480.

Eettpora celltilosa, Linn.
Suffolk, England.

Crag

FIG. 487.

Mi/ri/^iinni i>nnct<i.tHm, Phill. sp. Miocene; Ortenburg, Bavaria.
A, Zoarium, Vi- #, Upper surface, enlarged. In the forward portion
the apertures are open , in the rear, covered over by a calcareous
deposit. V, Cross-section of a branch.

raised and multiform ; usually there is a fissure below, or there may be a prominent
rostrum bearing an avicularium. Tertiary and Recent.

? Myriozoum, Donati (Myriopora, Blv. ; Vaginopora, Reuss), (Fig. 487). Zoaria
consisting of thick, dichotornously dividing branches, obtuse at their growing ex-
tremities, and rising from an attached basal expansion. Zooecia disposed about an
imaginary axis, even at the surface, their boundaries scarcely distinguishable. Entire
surface and also the inner walls minutely porous. Orifice above the centre of the
zooecium, sub-orbicular, notched, or canaliculate below. As a rule, the openings are
closed on the lower parts of the branches by a calcareous pellicle. Tertiary and
Recent ; perhaps also Cretaceous.
VOL. I

290

MOLLUSCOIDEA— BRYOZOA

SUB- KINGDOM V

Family 13. Celleporidae. Busk.

Zocecia urceolate, more or less erect, and irregularly crowded together ; often forming several

or many superimposed layers. Tertiary and
Recent.

Cellepora, Fabricius emend. Busk
(Spongites, Oken ; Cetteporcvria, Lamx.), (Fig.
488). Zoarium multiform, encrusting, or
erect and ramose. Zocecia in the older
portions more or less erect and very irreg-
ularly disposed. Orifice terminal, entire, or
sinuated, with or without internal denticles ;
in connection with it are usually one or
more rostra bearing avicularia. Inter-
calated avicularia generally present also.
The surface of weathered specimens dotted
by the unequal apertures of vesicle - like
cells. Tertiary and Recent.

FIG. 488.
Cellepora conglomerata, Goldf.

Astrupp, near Osnabrtick.
B, Upper surface, enlarged.

Oligocene :
A, Zoarium, 1/1-

Range and Distribution of the Bryozoa.

The class Bryozoa begins in the Ordovician, and is represented continuously up
to the present time. The older Palaeozoic forms belong chiefly to two sub-orders —
the Cyclostomata and Trepostomata.

A considerable number of Cydostomatous genera are present in the Ordovician,
all of them being closely related with Mesozoic and recent types ; but throughout the
remainder of the Palaeozoic, and in the Trias also, the sub-order is very sparingly
represented (if we except the somewhat doubtful Geramoporidae and Fistuliporidae),
and in some parts quite absent. In the Jura and Cretaceous, however, a remarkable
increase took place, hundreds of species being known from these formations. During
the Tertiary their strength was again materially reduced, and the living Oyclostomata
barely exceed 100 species in number.

The Trepostomata appear suddenly and in great variety in the Ordovician, from
which over 200 species are known, but entered almost immediately upon a period of
decline. From the Trenton and Cincinnati groups alone more species have been described
than from all of the later Palaeozoic formations put together. There is at present no
evidence to show that the group survived later than the Palaeozoic era, but it is not
unlikely that their descendants may be found among certain Mesozoic families, such
as the Geidae and Meliceritidae, which are provisionally assigned to the Cyclo-
stomata.

The Cryptostomata are likewise confined to rocks of Palaeozoic age, but, as has
been remarked above, may be very confidently regarded as the forerunners of the
Chilostomata. True members of the latter group are first met with in the Jura, but
they develop rapidly, and from the Cretaceous onward remain the dominant type.

The Triassic and Liassic Bryozoans belong chiefly to the Cerioporidae. This
family, together with the Diastoporidae, Fascigeridae, and other members of the
Cyclostomata, are abundantly represented in the Middle Jura of Lorraine, Southern
Germany, England, and Normandy. The Upper Jura, on the contrary, yields com-
paratively few Bryozoan fossils.

The Cyclostomata still predominate in the Neocomian and Gault, but in the
Cenomanian a number of Chilostomatous genera make their appearance. The fauna

CLASS ii BRACHIOPODA 291

is especially well devi-lnjK-'l in tin- vicinity of Le Mans, Havre, and Essen, and in
Saxony, Northern Germany, and Bohemia.

Bryozoans are surprisingly abundant in the Upper Cretaceous, particularly in the
Upper Planer of Northern Germany, Saxony, and Bohemia, in the White Chalk, and
the facies of Aix-la-Chapell.- and Maastricht. d'Orbigny alone has described not less*
than 547 species of Upper Cretaceous Cyclostomata, and about 300 Chilostoni'i'".

The Chilostomata retain their supremacy throughout the Tertiary period. The
Eocene and Oligocene deposits of the northern and southern slopes of the Alps are
remarkable for the ulmndaiKv of tht-ir Bryozoan remains ; some of the most noted
Eocene localities being Kressenberg, Hammer, and Neubeuern in Upper Bavaria ;
Mossano, Crosara, and Priabona, near Vicenza ; and Oberburg in Styria. The
Oligocene of Northern Germany, and the Miocene of Touraine, the Rhone Valley,
Upper Swabia, and the Vienna Basin, are also remarkably rich in Bryozoan remains.
The Pliocene fauna of Italy, Rhodes, Cyprus, and England (notably the Coralline Crag),
is made up almost entirely of existing genera, and in many cases of existing species.

[The entire systematic portion of the preceding Bryozoan chapter has been prepared for the
present edition W Mr. E. 0. Ulrich, whose important researches in this and other depart-
ments of invertebrate palaeontology are familiar to all students of the science. — TRANS.]

Class 2. BRACHIOPODA. Cuvier. Dumeril.1

Bwalved AjgttuMgidea with inequivalved, equilateral shells attached in extraneous
otyeds I y a posterior prulnniinlion. <>f flu' /-'/'///, or pedide^Jhroiujltoiif life or <liirinij only

1 Literature : A. Systematic Works.

von Buck, L., Ueber Terebrateln, Berlin, 1834. — King, W., A Monograph of Permiau Fossils
(Palaeont. Soc.), 1849. — Davidson, T., Monograph of British Fossil Brachiopoda, vols. I.-V. (Palaeont.
Soc.), 1851-86.— Hall, J., Descriptions and Figures of the Fossil Brachiopoda of the Devonian
(Palaeont. of New York, vol. IV.), l8Q7.—Quenstedt, F. A., Petrefactenkunde Deutschlands,
Bd. II., 1871. — Deslongcliamps- Eudes, E., Paleontologie Franchise, Terr. Jnrass. vol. IV., 1879. —
Jim-riDule, J., Systeme Silnrien du Centre de la Boheme, vol. V., 1879. — Waagen, W., Salt Range
Fossils (Palaeont. Indica, ser. XIII., vol. I.), 1882-85. — Deslongchamps, E,, Etudes critiques sur les
Brachiopodes nouveaux ou peu connus, 1884. — Davidson, T., A Monograph of Recent Brachiopoda
(Trans. Linn. Soc., vol. IV.), 1886-88.— Bittner, A., Brachiopoda der alpinen Trias (Abhaudl. der geol.
Reichs-Anst., Wien, Bd. XVI., XVII.), 1891-92.— Hall, J., and Clarke, J. M., Introduction to the
Study of Palaeozoic Brachiopoda (Palaeont. of New York, vol. VIII.), 1892-95.— Winchell, X. //.. and
Schuchert, C., The Lower Silurian Brachiopoda of Minnesota (Minn. Geol. Survey, vol. III.), 1893.

B. Anatomy, Embryology, and Classification.

Hancock, A., On the Organisation of Brachiopoda (Phil. Trans., vol. CXLVIII.), 1858.— Dull,
JT. //., A Revision of the Terebratulidae and Lingulidae (Amer. Journ. Conchol., vol. VI.), 1870. —
Morse, E. A., On the Early Stages of Terebratuliua septentrionalis (Mem. Boston Soc. Nat. Hist.,
vol. II.), 1873.— On the Systematic Position of the Brachiopoda (Proc. Boston Soc. Nat. Hist.,
vol. XV.), 1873. — Kovalevski, A. 0., Observation on the Development of Brachiopoda (Proc. Ini]>.
Soc. Amateur Nat. Moscow, vol. XIV.), 1874. — Brooks, W. K., The Development of Liugula and the
Systematic Position of the Brachiopoda (Sci. Results Chesapeake Zool. Lab.), 1878. — Shipley, A. E.,
On the Structure and Development of Argiope (Mittheil. Zool. Station Neapel, Bd. IV.), 1883. —
Oehlert in Fischer's Manuel de Conchyliologie. Paris, 1887.— BeecJier, C. E., and Clarke, J. M.,
The Development of some Silurian Brachiopoda (Mem. New York State Museum, vol. I.), 1889. —
Beecher, C. E., Development of the Brachiopoda (Amer. Journ. Sci., vols. XLI., XLIV.), 1891-92
— Revision of the Families of Loop-bearing Brachiopoda (Trans. Conn. Acad., vol. IX.), 1893. —
Beecher, C. E,, and Schuchert, C., Development of the Shell and the Brachial Supports in Dielasma
and Zygospira (Proc. Biol. Soc., Washington, vol. VIIL), 1893.— Hall, J., and Clarke, J. M., An
Introduction to the Study of the Brachiopoda (Report of the New York State Geologist, Parts I. and
TI.), 1892-93.— Schuchert, C., A Classification of the Brachiopoda (Amer. Geol., vols. XL, XIII.),
1893-94.— Synopsis of American Fossil Brachiopoda (Bull. U.S. Nat. Museum), 1896.— Crone, A.,
The Evolution of the Brachiopoda (Geol. Mag., vol. XXII.), 1895.

C. Bibliography.

Dcdl, W. H., Index to the Names which have been applied to the Subdivisions of the Class
Brachiopoda (Bull. U.S. Nat, Museum, No. 8), 1877.— Davidson, T., and Dalton, W. H., Bibliography
of the Brachiopoda (Palaeout. Soc.), 1886. — Schuchert, C., Synopsis, etc., see above.

292 MOLLUSCOIDEA SUB-KINGDOM v

on of 11i< -if existence, or cemented re /if rail//. }'alret rent nil and dorsal. In
composition, phosphatic or calcareous or both. Animal consisting of two pallial
cs intimately rein to I f<> flic •>/"'//. Jntlii.n. the inn idle cavity at the sides of the
inserted the two, 'more or less long, oral, usually spirally enrolled, cirrated

In'ii f]i in, u-Jiirli are n/riously modified, and are supported in the two terminal
superfamilies by an internal calcareous skeleton, or brachidium, attached to the dorsad
valve. Anus^^resentjor absent. Central nervous system consisting of an oesophageal
ring with weakly developed brain and infra-oesophageal ganglionic swellings. ^Blooil-
vascular system probably present with the sinuses developed into vascular dilatation*
at the backoj'tlie stomach and elsewhere. Sexes separate. __ Exclusively marine^

The class appeared in the Lower Cambrian, attained its maximum develop-
ment in the Silurian and Devonian, and is represented by about 140 living
species. Probably upwards of 6000 fossil and recent species have been
developed ; these are distributed in 322 genera, grouped in thirty-one families,
ten superfamilies, and four orders.

Cuvier (1792 and 1802) was the first to distinguish the Brachiopods from
the Acephala, and created for them a fourth family in his class of Molluscs.
To Dum6ril (1806) we owe the now generally accepted class name Bracliio-
poda, or arm-footed animals. Since the arms, or brachia, are not homologous
with the foot of Molluscs, Gray (1821) changed the name to Spirobranchiopoda ;
Blainville (1824) to Palliobranchiata ; Risso (1826) to Branchiopoda ; Broderip
(1839) to Brachiopodidae ; Agassiz (1847) to JSranchionopoda ; Bronn (1862) to
Brachionocephala ; Paetel (1875) to Branchionobranchia ; and Haeckel to Spiro-
Iminchia. None of these has displaced Dum6ril's term, though founded on a
false physiological interpretation of the brachia.

External Characters : Form. — The shells of Brachiopods are very
variable in form. Usually both valves are convex, but they may be nearly
flat, with the interior cavity extremely shallow, or the dorsal valvd may be
concave and follow closely the curvature of the convex ventral valve. The
ventral valve may be cone-shaped, with the dorsal operculiform, or the
former may be so modified by cementation as to assume the appearance of a
Cyathophylloid coral. The sjaelljs_cj3inni^ with the ventral beak,

or apex, more or less incurved over that of the dorsal valve, or the valves
may be very greatly extended transversely. In fact, the form of the shell of
Brachiopods is so variable that, as a rule, no greater value than specific can
be attached to this feature.

Fixation. — The animal is generally attached to extraneous objects by a
muscular pedicle which projects either from between the contracted posterior
margin of the two valves (Fig. 499, A), through an opening in or under the
beak (Fig. 498, £), or through the ventral valve (Fig. 512, A). With
increasing age, however, the pedicle opening frequently becomes closed, and
the pedicle itself atrophied. The animal may then be anchored by spines
(Chonetes, Productus) or be cemented by the whole or a part of the surface of
the ventral valve (Crania, Davidsonia, TJiecidea, Streptorhynchus). In some cases
(Glottidia and Lingula) Brachiopods live throughout life partially buried in the
sand or mud of the sea-bottom.

Ornamentation. — The external form and ornamentation of the shell afford
important characters for determining the species. The anterior margin of
one valve is frequently indented by a median sinus, and the other usually
exhibits a corresponding fold, or elevation.

< LASS II

293

In tin- earliest shell -ro\\tli >tap-s Ilrachiopod shells are invariably smooth,
and may remain so throughout lift1, but tliu greater number develop radial
striae, ribs, or undulations, and these arc usually crossed by concentric growth
lines, or lamellar, which arc sometimes of great width, or may IK- extended into
spines. There may be more or less long tubular spines scattered over one or
both valves, or sometimes restricted to a .-inude row along the cardinal line,
t'nder the term Lnri,-<it,n-, Leopold von Buch included all Brachiopods in which
the radial folds, or costae. are arranged in regular succession in such manner
that elevated ridges at the anterior margin of one valve coincide with the
indentations of the other. In the Biplicatac, a median fold or sinus is
bordered on either side by a broad fold. In the Cinctae, the plications of the
two valves meet at the anterior margin in such manner as to form a straight
instead of a crenulated line, as in the Biplicatae. In young specimens the
ribs and folds are less prominent and numerous than at maturity. In very old
or senile individuals the shell is usually thickened and obese, and the growth
lines are much crowded anteriorly. At this stage old specific characters are
seen to disappear, and at the same time new ones may be introduced.

Shell xtni<inre. — The test of Brachiopods is composed of laminae of various
structure and composition, but differs considerably from that of Molluscs.
The shell may
be wholly cal-
careous or alter-
nately calcareous
and corneous.
When entirely
calcareous the
laminae are
never more than
three in number :
an inner thick
prismatic layer,
an intermediate
laminar layer,
and an outer
epidermal film.

Thp innftr lavpr
''Iyer

is made up of

flattened prisms of calcite arranged parallel to one another with great
regularity, and forming an acute angle with the surface of the shell (Fig.
489). In the Thecidiidae these fibrous prisms are so intimately united with
one another that the shell substance appears almost homogeneous. Very
often the fibrous layer is perforated by a series of minute canals which pass
from one surface of the valve to the other in a more or less vertical direction,
and are somewhat dilated externally. These canals contain tubuli, or certain
prolongations derived from the mantle, but never communicate with the
exterior, owing to the fact that the laminar layer of the shell is always
covered with a chitinous epidermis (])en^'acmn). With the aid of a
magnifier the openings of these canals are visible in fossil forms, and they
may be also seen in recent specimens after the epidermis has been removed
by an application of caustic potash (Fig. 490). According to the presence

Fio. 489.

Prismatic fibrous struc-
tureof shell of Rhynchonella

(Hemithiir!*) y.x/M-.-m, itni/,
(after Carpenter).

A, Punctate exterior of a Terebratuloid shell, slightly
enlarged, li, Vertical section of shell of M«</cll<',<i<i
favescens, showing distally cnlar^-d tubules, 1(l"/].
C, Inner surface of Mi«fii,n.;<i shell showing ends nf
tubules and oblique calcareous prisms, iffy (after
Carpenter).

294 MOLLUSCOIDEA SUB-KINGDOM v

or absence of tubuli, Brachiopods are distinguished as punctate or im-
punctate.

The Craniidae have thick shells composed of concentric layers of carbonate
of lime. In Crania the shell substance is homogeneous, and punctured by
distally branching canals. In the Lingulidae and Obolidae the shell consists of
alternating layers of phosphate of lime, admixed with lime carbonate, and a
lustrous horny substance known as ceratin. The calcareous layers are pris-
matic, and are traversed by fine tubuli (Fig. 491). It is believed that the
function of the punctae is for respiration, but the fact that
these extensions of the mantle are not exposed to the water
may not accord with this explanation.

Valves. — Brachiopods are delicately constituted animals,
covered by two very vascular mantle lobes which secrete the
calcareous or corneo-calcareous valves, of which one is dorsal
FIG. 491. and the other ventral in position. The valves are often thin'
vertical section of and of unequal size, but the inequality is never of such a
showing5"''0 'alternate nature as to disturb the bilateral symmetry of the shell,
corneous («) and cai- During life the ventral valve, which is commonly the

careous (b) layers. , J,

strongly magnified larger of the two, occupies an inferior position, and the dorsal
let)' a superior. But in describing the shell, it is always so
oriented that the posterior margin, or hinge-line, is placed above, and the
anterior one below. A line drawn from the beak to the anterior margin
describes the length; and one at right angles to the same, in the direction of
right and left, the width; a third line drawn perpendicularly to the other
two, and passing through the centres of the valves, measures the thickness.
In the Protremata and Telotremata the ventral valve is convex, and curved in
such manner at the posterior margin as to form a beak. The beak may
be pointed, or it may be perforated by a round opening, or foramen, for
the protrusion of the pedicle. In many cases, however, the pedicle opening
lies underneath the apex of the beak, and sometimes encroaches upon a
portion of the dorsal valve. In the Atremata the pedicle emerges from
between the two valves ; in the Neotremata the posterior margin of the
ventral valve is notched, or there may be a small, circular, eccentric per-
foration, or a more or less long, narrow slit. In the Telotremata
the pedicle opening, or delthyrium, which is originally triangular
in form, becomes either wholly or partially closed by the
growth of deltidial plates. In the Protremata and certain of the
Neotremata, the delthyrium is closed by a true deltidium, as
this covering is called.

The cardinal area is a term applied to the flattened or curved FIG. 492.
triangular area which is frequently observable between the hinge-line Cyrtinahetewdyto,
and the beak (Fig. 492). It is more highly developed in the ventral ^^^hteharea
than in the dorsal valve, and is bisected medially by the triangular aad 5**ttdodel-
deltliyrium. A true cardinal area is absent in the Atremata and
Neotremata; but when a small area is present in these orders, it is called a false
cardinal area (Fig. 506, B, C). A split tubular structure, or syrinx, which partially
enclosed the pedicle, is developed in the delthyrium of some spire-bearing forms.

The deltidium has its origin in the Cephalula stage (Thecidea Mediterranea)
contemporaneously with the rudiments of the dorsal and ventral valves, while the
embryo is still in the free, swimming condition. The dorsal valve and incipient

CLASS ii BRACHIOPODA 295

deltidium appear first, being secreted by the rudimentary dorsal mantle and the dorsal
surface of the body, the latter subsequently becoming the pedicle. The ventral valve
is formed last, but is widely separated from the dorsal. Between the two valves is
placed the short and thick, but as yet unattached pedicle, on the dorsal surface of
which the third plate, known as the prodeltidium, still remains. Shortly before tin-
animal becomes fixed by the pedicle, the prodeltidium fuses with the posterior margin
of the ventral valve. The pedicle is at this stage entirely surrounded by shell, being
enclosed on one side by the ventral valve, and on the other by the deltidium. The
latter plate then continues to grow as one piece, extending from the apex in an
anterior direction, and is secreted entirely by the pedicle (Fig. 504). The del-
tidium is never punctate in structure, but it may bear spines (Aulosteges), and some-
times exhibits a round or pedicle perforation (Clitambonites). The deltidium is
characteristic of the Protremata, but it is also developed in some of the Neotremata
(Acrotretacea). This covering of the delthyrium is always present in the young of the
Protremata, but is absent in the Telotremata. In many of the Protremata (Orthidae,
etc.), the deltidium is only present in nepionic stages of the individual, being
resorbed at maturity ; but in the great majority of these forms it remains persistent
throughout life. In numerous Telotremata, the deltidial plates unite medially at
maturity, when they may resemble a true deltidium.

Deltidial plates occur only in the order Telotremata, and consist of two pieces,
which begin as narrow, linear, calcareous plates, growing medially from the walls of
the delthyrium. They gradually increase in size, and usually come in contact
medially with one
another, either below
or above the pedicle
foramen, and are
secreted by an exten-
sion of the ventral
mantle lobe. In this
respect they differ

from the deltidium FIG. 493.

of the Protremata, A, Rhynchonella vespertilio, with united deltidial plates. B, Terebratella dorsata,
irTiifTi ia 00r»raf0rl Tvir with discrete deltidial plates. C, Young specimen of Stringocephalus Burtoni, with
L D7 the deltidial plates united above the foramen.

the pedicle. The

deltidial plates are never present in the earliest growth stages of the -shell, the delthyrium
being then an open triangular fissure through which the pedicle is protruded. In the
adult stage the deltidial plates may remain as narrow, linear, discrete plates (Fig.
493, B) ; may meet beneath the pedicle foramen (Fig. 498) ; or they may wholly
enclose the pedicle (Fig. 493, A). The deltidial plates frequently unite, when they
closely resemble a true deltidium (Cyrtia, Cyrtina, Fig. 492) ; they are then termed a
pseudodeltidium.

The chilidium is a convex plate which often covers the cardinal process of the
dorsal valve in the Protremata. It is particularly well developed in the families
Clitambonititlae and Strophomenidae (Fig. 538, B). The chilidium is not to be homologised
with the deltidium, since it never appears earlier than the adolescent stage, and is
apparently a secretion of the dorsal mantle lobe. Both its prigin and phyletic signi-
ficance are therefore very different from those of the deltidium.

The listrium is a plate closing the progressive track of the pedicle opening or
pedicle cleft, in some Neotremata, posterior to the apex of the ventral valve.

Internal Characters of the SheU : Articulation. — The two valves are
held in apposition either by muscles only (Atremata and Neotremata), or they
are united by articulation (Protremata and Telotremata}. In the latter case
there are to be seen in the ventral valve a pair of cuneate or tooth-shaped

296

MOLLUSCOIDEA

SUB-KINGDOM V

projections, one on either side of the delthyrium, called the hinge-teeth (Fig.
498, £), which fit into the so-called dental sockets of tjie dorsal valve. Articu-
lation is also aided by the cardinal process, which is a more or less well-
developed apophysis of the dorsal valve, and is received between the teeth of
the ventral valve. By the contraction of the muscles attached to the
cardinal process, the valves are opened along the anterior and lateral
margins ; but when shut, the test entirely encloses the soft parts of the
animal.

The dental sockets are bounded on the inside by hinge-plates (Fig. 498, A),
which are often supported by vertical or inclined septal plates extending to
the bottom of the shell. The teeth of the ventral valve are sometimes
supported by lamellae known as the dental plates. In addition to the dental
plates, which frequently attain considerable size, there may be a median

FIG. 494.

Different forms of brachidia. A, Rhynchonella ; fleshy arms supported by two simply curved crura. B, Thc-
cospira ; inwardly coiled double spires, or spiralia. C, Nudeospira ; and D, Cyrtina ; outwardly coiled spiralia.
E-H, Loops of Brachiopods. E, Centronellu; F, Dielnsma; G, Terebmtella ; H, Megathyris.

septum of variable proportions. This may begin beneath the beak of the
valve, and may sometimes extend as far as the anterior margin (Fig. 498, A).
Some forms are also provided with lateral septa (Thecidiidae).

Brachial supports. — Of special systematic importance are the brachidia, or
internal skeleton of the fleshy arms (Fig. 494), which occur in the Spiriferacea
and Terebratulacea. The brachidia are, as a rule, united basally with the
crura, and are extremely variable in form. They usually pass through a
more or less complex series of metamorphoses during the growth of the
individual, and do not attain their complete development until the animal has
reached maturity.

The simplest form of brachial supports is found in the PJiynchonellacea and
Penlameracea, where it consists of two short, or only moderately long, curved
processes called the crura when discrete, and cruralium when the plates are
united. The crura are attached to the hinge-plates. The cruralium is

CLASS II

BRACHIOPODA 297

formed by the union of the crural plates in the Pentameracea. It serves
for the attachment of muscles, and may either rest upon the bottom of the
v.ilve, or may be supported by a median septum. When the crura remain
.-rparate, and are therefore not for muscular insertion, they are homologous
with and the equivalent of the crura in the Rhynchonettidae.

In the Spiriferacea, two thin, spirally coiled ribbons, or spiralia, are
attached to the crura ; the coils exhibiting great diversity in form, in the
number of volutions, and in the direction of the hollow cones (Fig. 494,
B, C, D). The spiralia are usually joined by a transverse band or jugum (Fig.
494, D). When the latter is discontinuous, the parts are called the jugal
processes. The bifurcations of the jugum may enter between the convolu-
tions of the spiralia, and may be continuous with them to their outer ends,
forming what is termed a double spiral or diplospire (Fig. 494, B). In the
Terebratulidae, the brachia are also attached to the crura, and form free,
shorter, or longer loops, which depend toward the anterior margin (Fig. 494,
E, F, G). The two descending branches may either unite directly or may be
joined by a transverse band; or the descending branches may recurve, continue
upward as ascending branches, and be connected posteriorly by a transverse
band. In the Terebratellidae, during all or some portion of the animal's
existence, the loops are attached to a median septum by outgrowths from
the descending lamellae. In the Stringocephalidae and Megathyrinae (Fig.
494, H), the descending branches are parallel to the lateral margins of the
shell, and unite along the median line ; but in some degenerate species, the
loop is represented by a transverse band situated centrally on the median
septum. The entire form of the brachidia is manifestly dependent upon the
character of the convolutions of the fleshy arms. In recent Rhynchvnellae
(Fig. 494, A} the brachia form hollow spiral cones, and if we imagine these
as supported by a calcareous framework, the result will be the form of
support seen in the Atrypidae. The fleshy arms of the Terebratellidae are
continuous with, and have at first the form of the loop, but later develop a
coiled median arm. Here the loops only have calcareous supports ; but in
the Spiriferacea, the entire brachia are provided with an internal calcareous
skeleton.

The changes in the form of the brachidia in the Telotremata during the
ontogenetic stages of the individual furnish very important data in regard
to the relationships existing between the different groups. In the Spiri-
feracea, not only do the number of convolutions of the spirals increase with
age, but the brachidia begin with Centronella- and Dielasma-like loops, from
the outer ends of which the spires are developed. Still more striking are
the metamorphoses which the loops of the Terebratulacea undergo. According
to Oehlert and Beecher, the loop of the living austral genus Magellania passes
through stages which correspond successively to those of Gwynia, Cistella,
Boucliardia, Magas, Magasella, Terebratella, and Magellania; and Friele has
shown that the metamorphoses of the loop in the boreal form Macandrema
criniiiim correspond in succession to the genera Platidia, Ismenia, Milhlfeldtia,
Terebratalia, and Macandrema.

A knowledge of the character of the brachidia in the Spiriferacea and
Terebratulacea is almost always requisite for critical generic determinations.
But an examination of the interior of the shell in fossil Brachiopods often
involves great difficulties, owing to the infiltration of calcite, or the filling up

298 MOLLUSCOIDEA SUB-KINGDOM v

of the shell cavity with sediment. Not infrequently the shell and the
brachidia are secondarily replaced by quartz ; and if »the interior filling matter
be dissolved away by dilute hydrochloric acid, exquisite preparations may be
obtained, often revealing the minutest details. Sometimes hollow shells are
found, in which the brachidia are well preserved ; but these structures
generally are more or less encrusted. It is often necessary to remove the
ventral valve, when the infiltrated material can be cut away by the use of
proper tools. Success in manipulations of this kind requires not only con-
siderable dexterity, but the conditions of preservation must have been very
favourable. The brachidia must be perfectly preserved, and the surround-
ing matrix must admit of being removed without injury to the specimen.
When other expedients fail, recourse can still be had to polishing, the shell
being gradually ground down by abrasion with emery powder on a glass
plate. The beaks are first ground away, until the first traces of the crura
appear ; the surface is then cleaned and kept moistened while a careful
drawing is made. Grinding is resumed for a short interval, when the
surface is again cleansed and drawn. This process is repeated until the
sections include the entire brachial support. From the series of transverse
sections thus obtained, the brachidium can be ideally reconstructed.

The spondylium is an internal ventral plate traversing the posterior
portion of the valve (Fig. 538, C). On the superior surface of the plate are
inserted the adductors, diductors, and the ventral pedicle muscles. Beneath
the spondylium, which may be supported by a median septum, are situated
the reproductive organs. The plate is homologous with the solid or ex-
cavated platform of the Atremata (Trimerellidae and Lingulasmatidae).

The Animal : Mantle. — Lining the entire inner surface of the shell is a
thin, transparent membrane, which appears in the embryonic condition as
two distinct lobes of the thoracic segment in the
Cephalula stage. This is the mantle or pallium,
which is primarily concerned in the secretion of the
shell. In Crania it consists of three layers : a middle
cartilaginous, an inner ciliated one, and an outer
layer of cells. The layer lying against the surface
of the shell is often studded with minute caeca or
blind tubes, which enter the perforations of the test.
__ The mantle (or certain of its layers) is folded upon

Flo. 495> itself at various points, enclosing cavities or pallial

HumUetonensis, sinuses, which contain the circulating fluids, and
! frequently portions of the genital organs. Distinct
Davidson) palHal sinuscs (aft€r imPressi°ns °f these sinuses are often observable in
the valves of both recent and fossil specimens (Fig.

495). In all the greater sinuses of the mantle, in the perivisceral cavity,
and in the cavernous brachia and cirri, occur calcareous spicules of various
shapes. These are especially abundant in the Thecidiidae, and form an
irregular mass or network. They appear to be absent in Magellania,
Terebratella, and Lingula. The outer margins of the mantle are thickened
and set with numerous, chitinous, simple, or barbed setae, sometimes of great
length.

The shell cavity is divided by a vertical membranous wall, which is an
extension of the mantle, into two regions : a posterior, or visceral cavity,

CLASS II

BRACHIOPODA

and an anterior, or brachial cavity. The posterior cavity contains the
principal viscera, the alimentary, circulatory, nervous, and muscular systems.
The anterior chamber is occupied by the arms.

Organs of the visceral cavity. — The membranous partition is pierced cen-
trally by the oval or slit-like mouth, from which the digestive tube extends
backwards as a simple or bent canal. In inarticulate species, the alimentary
canal is very long, makes several convolutions, and terminates in a well-
defined anus, situated on one side of the animal. In the Protremata and
Telotremata, the digestive tube is shorter and much simpler than in the
Atremata and Neotremata. The intestine makes a single convolution and
terminates blindly in the living representatives of these orders, being sur-
rounded by large hepatic lobes. In many Palaeozoic species it probably did
not terminate blindly, since the intestine passed through the hinge-plate by
a central foramen. There is no heart, circulation being apparently main-
tained by the cilia lining the vascular sinuses. These sinuses pass_inj:o the
perivisceral chambers, and are developed into vascular dilations at, the back
of the stomach and elsewhere. These bodies are not contractile, and their
function is unknown. Two numerously branched vascular trunks diverge
from the anterior portion of the perivisceral chambers, traversing the mantle
in either valve to its margins, and several others pass over the fleshy brachia
for their entire length. The nervous system consists of a circum-oesophageal
ring on which two supra-oesophageal ganglia are inserted. From the swell-
ings of the oesophageal ring (notably from that on the lower side), nerve
fibres are given off to the brachia, muscles, pedicle, and the two lobes of the
mantle. In adult Brachiopods, sense organs are not known with certainty ;
but in the embryos such are believed to be present. So far as is known
the sexes are always separate. The sexual organs in both male and female
are located essentially
alike, and have a paired
arrangement. Generally
they occupy the main
trunks of the vascular
sinuses, but may ex-
tend into the visceral
chamber, or in some of
the inarticulate forms,
may be restricted to the
latter.

The brachial cavity.— Fl0' m'

rp, r .LI. Liothyrina vitrea,

I he greater part ot the Linn. sp. Recent,
anterior, or brachial ^*™U& simply
cavity is occupied by
the spirally enrolled labial appendages, the so-called arms, or brachia. These
are two in number, one at each side of the mouth, and are of extremely
delicate constitution (Figs. 496, 497, and 494, A). The tissue of which
they are composed is essentially cartilaginous, and is traversed by several
circulatory canals as well as by a groove. The outer edges of the brachia
are fringed with long and movable cirri or tentacles, by means of which
currents are set up that conduct small food particles to the mouth. The
arms are frequently supported by a slender calcareous framework called

FIG. 497.

Magellania fiavescens, Val. Median vertical
section, slightly enlarged, rf, Spiral brachia ;
h, Fringed brachial margin ; pr, Cardinal process ;
2, Alimentary canal ; v, Mouth ; ss, Septum ; a,
Adductors ; c, cf, Diductors (after Davidson).

300

MOLLUSCOIDEA

SUB-KINGDOM V

the brachial supports, or bra'chidia, described above. There are no special
respiratory organs, the blood being oxygenated in the inner surface of the
mantle and in the spiral arms, where it is brought into close osmotic relation
with the water.

Muscular system. — By means of muscles Brachiopods are enabled to open
and close their valves, and to a limited extent can protrude and retract the
pedicle. In the articulate forms (Protremata and Telotremata) there are three
sets of muscles — namely, the diductors, which by contraction open the valves ;
the adductors, which by contraction close the valves ; and the pedicle muscles,
or adjusters, which also by contraction withdraw the pedicle. The points of
attachment of these muscles leave more or less distinct impressions in the
valves of both recent and fossil Brachiopoda, and the subject is therefore
worthy of careful examination.

The adductor, or closing muscles are attached on either side of the median line
in the dtffumJ. valve, and leave two elongate scars lying immediately to the right and

left of the median line,
enclosed between the
diductors (Fig. 498,5, a).
These muscles extend
almost directly from one
valve to the other, and
as each muscular band is
once divided, their inser-
tions on the dorsal valve
are quadruple. Their
impressions on this valve
are known as the anterior
and posterior adductors
(Figs. 498, A, B, a, a'}..
The principal diduc-
tors, or opening muscles,

Magellaniajlavescens, Val. Recent ; Australia (after Davidson). A, Dorsal originate at the anterior
valve. B, Ventral valve. D, Deltidial plates. F, Foramen. S, Loop, pr, ventral edge of the V1S-
Cardinal process; x, Hinge-plate; z, Hinge-teeth; a, a', Impressions of , -, .,-,

adductors ; a, d', Didnctors : p, P', Pedicle muscles. ceral area, and on either

side of the median line ;

the scars of these muscles being usually the largest and deepest of any in the animal.
They taper rapidly in crossing the interior cavity, and their small extremities are
attached to the anterior portion of the cardinal process. There are also inserted on
the cardinal process, behind the principal diductors, two much smaller muscular bands,
which are called the accessory diductors. Their attachment on the ventral valve is
represented by two feeble scars in the posterior part of the muscular region, but these
are rarely observable in fossil specimens (Fig. 498, A, B, d).

When a functional pedicle is present, there are found in addition to the valvular
muscles two pairs (one to each valve), and a single unpaired muscle ; these are
attached to the pedicle, and are called the pedicle muscles (Fig. 498, B, p,p"). The pair
in the ventral valve originates immediately outside of and posterior to the adductors
and diductors ; the pair in the dorsal valve is attached behind the posterior adductors ;
and the unpaired muscle lies at the base of the pedicle in the ventral valve. Only
the latter unpaired band, as a rule, leaves a perceptible scar in fossil specimens.

The entire muscular system in the Protremata and Telotremata works with the
utmost precision. The cardinal process is received between the teeth of the ventral
valve in such a manner as to allow the dorsal valve to swing freely in the median

FIG. 493.

CLASS II

BRACHIOPODA

301

vertical plane as on hinges, and at the same time prevents motion in a lateral
direction. The diductors, being attached to the cardinal process, act upon a
,-irm when they contract, thus opening the valves,
while the contraction of the adductors serves to close
them (Fig. 497).

In the Atremata and Neotremata the muscles are
arranged differently, arid are often more complicated
and numerous, as articulation is usually not present
in these orders. The greatest complexity is attained
in Lingula (Fig. 499), because these animals, in
addition to the absence of articulation, slide their
valves laterally.

Ontogeny. — The development of Brachio-
pods from the egg to maturity may be divided
into two periods : (a) stages of growth from the
egg to that condition in which the animal is
recognisable as possessing some distinctive class
characters ; and (b) from the first shelled condi-
tion, or protegulum, to maturity and old age.

Our knowledge of the earliest embryonic condi-
tions is restricted to Terebratulina, Liothyrina, Cistella,
and Thecidea. After fertilisation the larvae may remain
attached, and pass their early stages within the parent ;
or they may develop cilia before segmentation, and be
set free in the pallial chamber or in the sea-water.
The free larvae swim by the aid of cilia with a twirling motion. There are five well-
marked stages of growth before the larvae can be definitely recognised as Brachiopods.
These are : (1) The Protembryo, which includes the ovum, its segmented stages preced-
ing the formation of a blastula, or primary
internal cavity (Fig. 500, A, B) ; (2) the Mes-
embryo, or blastosphere, a multi-segmented larva
with an internal cavity (Fig. 500, C) ; (3) the
Metembryo, or gastrula stage (Fig. 500, D) ;
(4) the Neoembryo, or segmented ciliated

ABC D

FIG. 501.

Cistella Neapolitana, Schacchi. A, Neoembryo ;
embryo of two segments. 11, Neoembryo ; cepha-
lula, ventral side, showing cephalic, thoracic, and
caudal segments, eye-spots, and bundles of setae.
C, Neoembryo; lateral view of completed cephalula
stage, showing extent of dorsal (<0 and ventral (<•)
mantle lobes, and umbrella-like cephalic segment.
(A and Ji after Kovalevski, C after Shipley ; all
reproduced from drawings by Beecher.)

FIG. 499.

Lingula anatina, Brug. Recent.

A, Shell with pedicle, natural size

B, Interior of ventral valve show-
ing muscular impressions ; a, Ad-
ductors ; c, Protractors ; p, Re-
tractors ; o, Pedicle muscle.

FIG. 500.

Cistella Neupolitunn, Schacchi. Recent. A,
Protembryo ; unsegmented ovum. B, Protembryo ;
ovum composed of two spheres. C, MeseniKrv \ ;
blastosphere. D, Metembryo ; Gastrula v.it'tcr
Shipley, from Beecher).

Cephalula, which consists at first of a cephalic lobe, bearing eyes in Cistella, and a
caudal lobe, to which is added later a thoracic segment carrying four bundles of
setae. At the same time the dorsal and ventral sides of the latter segment become
extended over the caudal lobe, and are progressively defined as two lobes (Fig. 501) ;
(5) the Typembryo, or larval stage, in which the dorsal and ventral thoracic lobes,
or mantle, fold over and enclose the cephalic lobe (Fig. 502, B). Upon the mantle
lobes, either before or after turning, there is a corneous integument which develops
into the protegulum. before the formation of the true shell. The caudal segment

302

MOLLUSCOIDEA

SUB-KINGDOM V

becomes the pedicle, and may in this stage serve to attach the larvae to foreign objects,
or the pedicle may remain undeveloped for a time. A rudimentary digestive tract is
present, and also four pairs of muscles, which later become the adductor, diductor, and
ventral pedicle muscles.

In the Phylembryo the embryonic shell, or protegulum, is completed ; the tentacular
lobes of the lophophore, or brachia, appear ; the four bundles of setae are dehisced ;
obsolescence of the eyes occurs, as well as the agree-
ment of the muscular system with that in adult forms.

The protegulum has been observed by Beecher in
many genera, representing nearly all the leading
families of the class, and therefore it may be inferred
that the protegulum is common to all Brachiopods.
It is semi-circular or semi-elliptical in outline, with a

FIG. 502.

Cistella Neapolitana, Schacchi. A, Neoembryo ; completed cepha-
lula stage. B, Typembryo ; transformed larva resulting from folding
upwards of mantle lobes over cephalic segment; ad, Muscles from
bundles of setae to sides of body cavity ; di, Muscles from dorsal to
ventral sides of body ; vp, Muscles from ventral side of body to caudal
segment or pedicle (after Kovalevski, from Beecher).

FIG. 503.

Cistella Neapolitana, Schacchi.
A, Phylembryo; Brachiopod show-
ing shell (protegulum), beginning
of tentacles of lophophore (I), ob-
solescence of eye-spots, and forma-
tion of oesophagus ; t, Hinge-teeth ;
vp, Ventral pedicle muscles. B,
Nepionic Brachiopod, showing
distinct tentacles of lophophore,
mouth and stomach, and trans-
formation of muscles from typern-
bryo ; od, Adductors ; di, Divari-
cators ; vp, Ventral pedicle muscles
(after Kovalevski, from Beecher).

straight or arcuate hinge -line, and no cardinal area. The prototype preserving
throughout its development the main features of the protegulum, and showing no

separate or distinct stages of growth, is
represented by the genus Paterina (Fig.
505).

So far as observed, the protegulum,
or Paterina stage, in the Atremata and
Telotremata is followed by the Obolella
stage of nearly circular outline. After
Recent, this stage, specific characters appear, and

Telotremata
is, Beginning of dorsal valve ; 'del, Shell plate forming there are usually developed the first rudi-

•iide of body ; p, Pedicle. B, Dor

FlG 504

Thecidia (Lacazella) Mediterranea, Risso.

ADowo- ventral longitudinal section of cephaiuia ; in the open delthvrium of the
h, Head ; d, Dorsal mantle lobe ; v, Ventral mantle lobe ; . . ". , , ^

on dorsal side of body ; p, Pedicle. B, Dorso-ventral morifa ^f fU0 /lolHYIial r>lafp<a Tn flip

longitudinal section of typembryo ; vs, Ventral valve ; ments ot tne deltldial plates. In t

hi, Hinge-line of dorsal valve. C, Adult specimen seen Protremata, the Paterina stage is not

from the dorsal side, showing ventral area and deltidium. «. n TT •, , ,, p., , 11o .,„' r.-.f +1,,.

(A and B after Kovalevski ; C after Beecher.) followed by the Obolella Stage, but tlie

wide delthyrium of the protegulum is at

once affected and modified by the prodeltidium, which develops into the deltidium.
In the Acrotretacea, belonging to the Neotremata, there is often developed a true
deltidium, showing the close relationship of the order with the Protremata, and the
dissimilarity of these two orders to Atremata and Telotremata. In the Discinacea,
belonging to the Neotremata, the pedicle opening is an open notch in the posterior

CLASS II

BRACHIOPODA 303

margin of the ventral valve. In derived forms this is progressively closed posteriorly ;
geologically in the phylum, and ontogenetically in the latest derived individuals.

Habitat and Distribution. — Brachiopods are usually gregarious in
habit, often growing in clusters attached to one another. This is not only
true of recent species, but of Palaeozoic forms as well. Brachiopods are found
in all latitudes and at all depths, occurring most abundantly between tides
and 278 fathoms. Liothyrina Wymllii was dredged from the enormous depth
of 2945 fathoms. Terebratulina caput-serpentis ranges from a few fathoms to
a depth of 1195 fathoms.

Brachiopods are most prolific in warmer seas, the Japanese province having
nearly thirty species. As a rule, those occurring in cold waters are not found
in warm waters. Oehlert has shown, however, that a few species are world-
wide in their distribution (Liothyrina mtrea, var. minor and Terebratulina caput-
serpentis), and that they also have great bathymetric range. Some generally
distributed Palaeozoic species are Atrypa reticularis, Leptaena rhomboidalis, and
Product us semireticulatus.

Migration of Brachiopods is possible only during the early larval stages,
and then to a very limited extent. Morse observed that Terebratulina became
attached in a few days, but Miiller kept Discinisca in confinement nearly a
month before any became sessile. Deep-sea Brachiopods are usually thin-
shelled, brittle, and translucent.

Colour. — " The shells of most living species are of light or neutral tints,
white or horn-colour. A deep orange-red in radiating bands or in solid tints,
colours some species (Terebratulina, Kraussina, etc.) ; light yellows, deep and
light shades of green (Lingula), black in bands (Crania), or masses (RJiyncJumella)
embellish these shells. Even among the fossil species traces of faded colour-
marks are occasionally observed ; Deslongchamps has described them among
Jurassic species, Davidson among the Carboniferous, and Kayser has found a
colour-marked Rhynchondla in the Devonian. The large highly ornamented
species of Palaeozoic times, with their external sculpture heightened by a
brilliant colouring, must have been objects of exquisite beauty " (Hall and
Clarke).

Classification. — The Brachiopoda, since 1858, have been divided by
nearly all systematists into two orders, based on the presence or absence of
articulating processes. These divisions, " Artieules and Libres," were recog-
nised by Deshayes as early as 1835, but not until twenty-three years later
were the names Lyopomata and Arthropomata given them by Owen. These
terms have been generally adopted by writers, though some prefer Inarticulate
and Articulata, Huxley, or Bronn's Ecardines and Testicardines. Bronn (1862)
and King (1873), while retaining these divisions, considered the presence or
absence of an anal opening more important than articulating processes, and
accordingly proposed the terms Pleuropygia and Apygia, and Tretenterata and
Clistenterata respectively. In many Palaeozoic rostrate genera of Clistenterata,
it has been shown that an anal opening was also present, and therefore the
absence or presence of this organ is not of ordinal value.

The first attempt to construct a classification of the Brachiopods was that
of Leopold von Buch, who took for his principal differential characters the
conformation of the umbonal region, the presence or absence of a pedicle, the
nature of the delticlium, and the external form and ornamentation of the shell.

304 MOLLUSCOIDEA SUB-KINGDOM v

While his classification lacks a perfect understanding of the features in question,
it is remarkable that von Buch, nearly sixty years ago, and Deslongchamps,
twenty-eight years later, recognised some of the* principles upon which the
classification of the Brachiopoda is now established, viz. the nature of the
pedicle opening.

Up to 1846 the general external characters of the Brachiopods served the
majority of authors as the essential basis for generic differentiation. In that
year, however, King pointed out that more fundamental and constant
characters exist in the interior of the shell, a fact which soon came to be
generally recognised, mainly through the voluminous and admirable contribu-
tions of Thomas Davidson.

Waagen in 1883 found it "absolutely necessary" to divide Owen's two
orders into seven sub -orders. The basis for these sub -orders rests on no
underlying principle of general application, and yet five of these divisions are
of permanent value, for each contains an assemblage of characters not common
to the others.

No classification can be natural and permanent unless based on the history
of the class (chronogenesis) and the ontogeny of the individual. However, as
long as the structure of the early Palaeozoic genera remained practically un-
known, and the ontogeny wholly unrevealed, nothing of a permanent nature
could be attempted. In the recent and very excellent volumes by Hall and
Clarke (Palaeontology of New York, vol. viii.), the great majority of the
Palaeozoic genera are clearly defined. The ontogenetic study of the Palaeozoic
species was initiated in 1891 by Beecher and Clarke, followed by Beecher,
and more recently by Schuchert ; and their results combined with those derived
from the study of the development of some living species, such as have been
published by Kovalevski, Morse, Shipley, Brooks, Oehlert, Beecher, and
others, confirm the conclusion reached through chronogenesis. Moreover, the
application by Beecher of the law of morphogenesis, as defined by Hyatt,
and the recognition and establishment of certain primary characters have
resulted in the discovery of a fundamental structure of general application for
the classification of these organisms. It has for its foundation the nature of
the pedicle opening and the stages of shell growth. On this basis Beecher
(1891) has divided the class into four orders: the Atremata, Neotremata, Pro-
tremata, and Telotremata.

The nature of the pedicle opening being employed for ordinal divisions,
persistent internal characters of the shell are, as a rule, used for superfamily
purposes. Such are the presence or absence of a spondylium, brachial supports,
etc. Family divisions are based upon a combination of external and internal
generic characters, such as the outer form, nature, and position of muscles,
internal plates, etc.

No division, however, has any value unless tHe group contains forms of
but one phylum, since a phylum or line of descent cannot originate twice.
However, it happens that the same or nearly the same combination of mature
characters is developed along different lines ; and when this occurs the
ontogeny will show it. It is therefore not correct to group different stocks
under one and the same genus. For instance, the family Terebratellidae
probably divided during early Mesozoic times, one stock drifting into boreal
and another into austral regions. These two stocks agree structurally in the
earliest shelled condition and also at maturity ; but between these two stages

ORDER I

ATRKMATA

805

of growth, the austral group (.l/^/r/A//,/m>r) passes through a different series
of loop metamorphoses from the boreal one (Dallinae).

It was by the application of the above-mentioned prinnpk-s that Srhuchcrt.

in 1893, arranged all the genera of Brachiopoda under the four orders
instituted by Beecher. Further attention has since lu-cn -i\en to this subject
by the same writer, and the classification outlined in his SynOptM of Aim ri«n<
Fossil Brachiopoda has been adopted in the present work.

Order 1. ATREMATA. Beecher.

Inarticulate Br<n-hi<>i'<nhi with the pedicle emerging freely between the two valves,
the opening being more or less sha.ml !>// Imfli. Growth taking place mainly around
the anterior and lateral margins, never enclosing or surrounding the pedicle. Aperture
unmodified. Prodeltidium attached to dorsal valve.

Superfamily 1. OBOLACEA. Schuchert.

Rounded or semi-circular, and more or less lens-shaped, thick-shelled, primitive
Atremata, fixed by a short pedicle throughout life to extraneous objects. Cambrian
to Silurian.

Family 1. Paterinidae. Schuchert,

Obolacea with nearly semi-circular valves without cardinal areas,
ami with the entire, gaping, posterior region occupied by the pedicle.
This is the simplest shelled condition of the class, and is repeated
ontogenetically as the protegulum, or initial shell, probably through-
out the class. Cambrian.

Paterina, Beecher (Fig. 505). Of this North American
genus, the only one of the family, about six species are
known.

Family 2. Obolidae. King.

Georgia, Vermont. A,

Thick-shelled Obolacea, of nearly circular or ovoid outline, yjjjjjj \^^ $l\ou£ '
biconvex, usually smooth, and with rudimentary cardinal areas specimen, s/j "(after
traversed by shallow pedicle grooves. Muscular scars distinct,
consisting of two pairs of adductors and three of sliders, or adjusters. Cambrian.

Under this family are included some of the oldest known Brachiopods. The
family is abundantly represented in the Lower and Middle Cambrian.

Obolella, Billings (? Dicellomus, Hall). Small, oval, or round shells, with

Bill.

FIG. 505.

1'uterina Labr<"

Cambrian ; near

FIG. 506.

Obolus Appollnis, Eichw. Cambrian ; St. Petersburg, Russia. A, Exterior
of dorsal valve. £, C, Interior of ventral valve. D, Interior of dorsal valve
Natural size.

Fio. 507.

Spondylobolv*
luris, M'Coy. Ordovician ;

Ireland. Natural si/r
(after Davidson).

narrow cardinal' areas. Dorsal valve usually with a rudimentary hinge facet.
North America and Europe.

VOL. I Y

306 MOLLUSCOIDEA— BRACHIOPODA SUB-KINGDOM v

Elkania, Ford (Billingsia, Ford). Like Obolella, but with a small platform
in the dorsal shell. North America.

Obolus, Eichwald ( Ungula, Pander ; Ungulites, Bronn ; Aulonotreta, Kutorga ;
Acritis, Schmidtia, Volborth), (Fig. 506). Much like Obolella externally, but
larger and with more prominent cardinal areas in both valves. Ventral valve
with a median septum extending to about the centre of the valve. 0. Appolinis,
Eichwald, occurs in vast numbers in the Unguliten-Sandstein of Russia.

Neobolus, Waagen ; India. Botsfordia, Matthew • New Brunswick. Spondyl-
obolus, M'Coy (Fig. 507). Ireland.

Family 3. Trimerellidae. Davidson and King.

Large, thick-shelled, inequivalved Obolacea, with the ventral cardinal area usually
very prominent, triangular, and tranversely striated. Adjuster and anterior adductor
muscles elevated upon solid or excavated platforms. Cambrian to Silurian.

Dinobolus, Hall (Conradia, Hall; Obolellina, Billings). Cardinal area not so
prominent as in the other genera of this family. Platform small, with abruptly
conical vaults. Ordovician and Silurian ; North America, Great Britain,
Bohemia, Gottland, and Esthonia.

Monomerella, Billings. Similar to Trimerella, with well-developed platforms

FIG. 508.

Trimerella Lindstroemi, Ball sp. Silurian ; Gottland. x i/o. A, Shell seen from the dorsal side. B, C, In-
terior of dorsal and ventral valves, respectively. D, Cast. (A and B a/ter Davidson ; Cand D after Lindstrbm.)

in both valves ; that of the dorsal valve, however, but slightly excavated.
Silurian ; North America, Gottland, and Livonia.

Trimerella, Billings (Gotlandia, Dall), (Fig. 508). Platforms long, narrow,
well -developed, and doubly vaulted. Dorsal beak often thickened into a
prominent apophysis extending against the cardinal slope of the ventral valve.
Silurian ; North America, Gottland, and Faro.

Pihtiiobolus, Hall. Silurian ; North America. (?) Lahkmina, Oehlert (David-
sonella, Waagen). Lower Cambrian ; India.

Superfamily 2. LINGULACEA. Waagen.

Elongate, thin-shelled, burrowing, derived Atremata, with a more or less long,
worm-like, tubular, flexible pedicle. Cambrian to Recent.

Family 1. Lingulellidae. Schuchert.

Spatulate, inequivalved Lingulacea, structurally intermediate between the Obolidae
and Lingulidae. Cambrian and Ordovician.

ORDER I

AT1IK.MATA

307

Tin- family contains the oldest LiliguloiJ shells, the member.* of which still retain
a preponderance of Oboloid characters. The first true Linyulae appear in the Lower
Ordovician.

, Salter. Linguloid shells with the ventral cardinal area more
or less elevated beyond the dorsal shell, and bisected medially by a narrow
pedicle furrow. Cambrian ; North America and Europe.

This genus is not well known, and the species referred to it may belong to two
or more genera. The Lower Cambrian forms have decided Obolella-likr muscular
scars, while those of the type species seem to be more in harmony with /,/////>//•/.

Lingulepis, Hall. Pedicle valve generally much produced at the beak,
with no distinct cardinal area ; dorsal valve more or less ovate. Cambrian ;
North America.

Leptobolus, Hall. Very small Linguloid shells, with well-developed, dis-
tinctly grooved, cardinal areas in both valves. Interior marked by two or
three diverging, slightly elevated septa, which sometimes are somewhat
bifurcated terminally. Ordovician ; North America.

(?) Pater-Ida, Barrande. Ordovician ; Bohemia and North America.
(?) Mickwitzia, Schmidt. Lower Cambrian ; Sweden.

Family 2. Lingulidae. Gray.

Attenuate, sub-quadrate, or spatulate, almost equivalved Lingulacea, with a more

or less long, tubular, flexible pedicle. Muscles
highly differentiated and consisting of six ^<"Y>.
two of adductors, and four of sliders, or ailjnstors.
Ordovician to Recent. Maximum develop-
ment in Ordovician, declining after Devonian
time.

Lingula, Bruguiere (s. g. Glossina, Phill.),
(Figs. 509 and 510). Shell thin, usually com-
pressed, glistening, generally smooth, or with
fine, concentric, more rarely with both con-
centric and radial striae; broad over the
pallial region, tapering more
or less toward the beaks.
Ordovician to Recent. Maxi-
mum development in Silurian
and Devonian.

Glottidia, Dall. Like the
FIG. 509. FIG. 510. preceding, but interior of ven-

Lingulaanatina, Brug. Recent. A, Shell I Ltn - <>w. tral valve with two SCDtal

with pedicle. ^Interior of ventral valve. Silurian ; Gottland. ^^ diverging from the

beaks. 'Dorsal valve with a single median ridge. Recent ; American seas.

Dignomia, Hall. Both valves with median septal ridges; that of the
dorsal valve stronger, and flanked by two submarginal diverging ridges,
which correspond in position to grooves in the ventral valve. Middle De-
vonian ; North America.

Barroisella, Hall and Clarke. Lingulae with rudimentary articulation.
Silurian to Devonian ; North America ; (?) Bohemia.

308 MOLLUSCOIDEA — BRACHIOPODA SUB-KINGDOM v

Thomasina, Hall and Clarke. Lingulae with the posterior margin of the
ventral valve notched, and with two conspicuous articulating processes.
Silurian ; France.

Family 3. Lingulasmatidae. Winchell and Schuchert.

Platform -bearing Lingulacea derived through Lingulidae. Ordovician and
Silurian.

Lingulops, Hall. Small Lingulae with narrow, depressed, not excavated,
platforms. Ordovician and Silurian f North and South America.

Lingulasma, Ulrich. Large thick-shelled Lingulae with very prominent,
slightly excavated platforms. Ordovician ; North America ; (?) England.

Order 2. NBOTRBMATA. Beecher.

Circular or oval, more or less cone-shaped, inarticulate Bmchiopoda, with the
pedicle opening restricted throughout life to the ventral valve. Pedicle aperture
modified by a deltidium or listrium. Prodeltidium attached to the ventral valve.

Superfamily 1. ACROTRETACEA. Schuchert.

Neotremata with phosphatic shells and a more or less well-developed deltidium .
Dorsal protegulum marginal. Cambrian to Silurian.

Family 1. Acrotretidae. Schuchert.

Acrotretacea with the pedicle opening posterior to the protegulum. Cambrian to
Silurian.

Acrotreta, Kutorga. Ventral valve sub-conical ; the posterior margin
flattened, triangular in form, and resembling a true cardinal area. This
slope is divided medially by a shallow groove, widening downward. Circular
pedicle opening at the apex of the valve. Dorsal valve flat or depressed,
convex ; interior flanked by a large anterior and a smaller posterior pair of
muscular impressions ; exterior concentrically striated. Cambrian and Ordo-
vician ; North America and Europe.

Conotreta, Walcott. Small, highly conical shells, with the interior of the
ventral valve marked by a number of radiating ridges. Ordovician and
Silurian ; North America.

Acrothele, Linnarsson. Rounded, or broadly oval, depressed shells with
the cardinal area obsolete. Cambrian ; North America and Europe.

Linnarssonia, Walcott. Smaller and more conical shells than Acrothele.
Cambrian ; North America and Europe.

Discinopsis, Matthew ; New Brunswick. Iphidea, Billings ; North America
and Sweden. Volborthia, von Moller ; Russia. (?) Mesotreta, Kutorga ; Russia.
(?) Orbicella, d'Orbigny (Keyserlingia, Pander). (?) Helmersenia, Pander ; Russia.
All Cambrian.

Family 2. Siphonotretidae. Kutorga.

Acrotretacea with the pedicle opening passing by resorption anteriorly through the
protegulum and the umbo of the shell. Cambrian to Silurian.

ORDER ii NEOTREMATA

Siphonotreta, de Vern (Fig. 511). Shell elongate-oval, moderately convex.
Pedicle opening at the apex, and communicating with the interior of the
shell by a tubular canal.
Cardinal area and del
tidiuni not developed.
Shell ornament (M! with
concentric lines and
ridges; the epidermal
layer bearing hollow

spines, though rarely K|(: M1

preserved. Layers be- .SV/.AO^^V^ wngvAovktta, i:\i-\\\\-. ordovu-ian ; st. Petersburg. >/,.

noatli tlio nrkirlormia A> B> Interior of v.-ntral and dorsal valves, respectively. C, I), Worn

neath the epidermis ex'ter'ior of ghcll . ventral antl dorgal asi,.'i-ts.

punctured by radiating

and branching tubules. Ordovician and Silurian ; Europe and (?) North

America.

Schizambon, Walcott (Schizambonia, Oehlert). Small depressed Siphono-
tretae without tubular pedicle canal. Ordovician ; America and Russia.

Trematobolus, Matthew. Siphonotretae with rudimentary articulation.
Middle Cambrian ; New Brunswick.

Superfamily 2. DISCINACEA. Waagen.

Neotremata with phosphatic shells, a listrium, but no deltidium. Dorsal pro-
fegulum usually sub-central. Cambrian to Recent.

Family 1 . Trematidae. Schuchert.

Primitive Discinacea, in which the posterior margin of the ventral valve has a
triangular pedicle notch throughout life. A listrium usually present. Cambrian to
Carboniferous.

Discindepis, Waagen. Small, nearly flat, inequivalved shells. Pedicle
notch very small. Characters very primitive. Lower Cambrian ; India.

Trematis, Sharpe (Orbicella, d'Orb.) Ventral valve unevenly convex,
more or less depressed over the posterior region. Pedicle fissure large, ex-
tending from the apex to the posterior margin. Dorsal valve evenly convex,
and sometimes with incurved beak ; posterior margin much thickened, and
broadly grooved for the passage of the pedicle. Surface of both valves
covered with punctures or small pittings arranged either in quincunx
or in radiating rows. Ordovician and (?) Silurian ; North America and
(?) Europe.

Schizocrania, Hall and Whitfield. Ventral valve flat or concave, smaller
than the dorsal, and bearing a deep and very broad triangular pedicle
notch, which extends from just behind the beak to the posterior margin.
Apex of notch occupied by a triangular plate, or listrium. Surface
marked by concentric growth lines ; no muscular impressions visible on
the interior. Dorsal valve more or less convex, with beak marginal.
External surface radially striated. On the interior, a low median ridge
extends from the apex to beyond the centre of the valve ; posterior adductor
muscles strong : the anterior ones faint. Ordovician to Devonian ; North
America,

MOLLUSCOIDEA— BRACHIOPODA

SUB-KINGDOM V

Oehlertella, Hall and Clarke (Lingulodiscina, Whitfield). Much like Schizo-
crania, but the ventral valve has concentric growth lines, and no radiating
striae. Ventral pedicle area greatly elevated and transected by a narrow
open fissure. Devonian to Lower Carboniferous ; North America.

Schizobolus, Ulrich. Devonian ; North America. (?) Monobolina, Salter.

Family 2. Discinidae. Gray.

Derived Discinacea with an open pedicle notch, in early life, in the posterior
margin of the ventral valve, which is closed posteriorly during neanic growth, leaving
a more or less long, narrow slit, partially closed by the listrium. Ordovician to
Recent.

Orbiculoidea, d'Orbigny (Fig. 512). Shells inequivalved, sub-circular, or sub-
elliptical in outline. Apices eccentric. Ventral valve depressed, convex, or"
R flattened. Dorsal valve larger, usually de-

pressed, conical. Pedicle furrow originat-
ing behind the apex, extending over a
greater or lesser portion of the radius of
the valve, and produced at the distal end
into a short tubular sipho, emerging on the
interior surface near the posterior margin.
Surface with fine, crowded or distant,
rarely lamellose, concentric lines occasion-
ally crossed by radiating lines. Ordovician
to Cretaceous ; North and South America,
Sub-Carbonifer- Europe, and probably elsewhere.

A- • T TT i TI

Discina, Lamarck. Very much like
Orbiculoidea, but the pedicle emerges through the ventral shell antero-
posteriorly,' immediately beneath the beak, instead of through a sipho postero-
anteriorly as in that genus. Recent.

Until recently, Discina embraced all fossil Discinoid shells, but at present
this genus seems to be restricted to a single species,
D. striata, living off Cape Palmas, West Africa.

Discinisca, Dall (Fig. 513). Like Orbiculoidea,
but with a small septum, as in Discina, behind
which is an impressed area, externally concave and
internally elevated. This is perforated by a longi-
tudinal fissure, extending from a short distance
behind the septum nearly to the posterior margin. Peru- , A> Side^ieJ:v;, ?> ^terior of

^ ,. ^: wi-.Vi. • • -, -^ ° ventral valve. C, Exterior of same.

FIG. 512.

Billings). B, 0. nitida, Phill.

ous ; Missouri, x, Dorsal ; y, Ventral valve, Vi-

FIG. 513.
Discinisca lamellosa, Brod. Recent ;

Russia and North

Tertiary to Recent ; North America and Europe.

Schizotreta, Kutorga. Ordovician and Silurian;
America.

Lindstroemella and Roemerella, Hall and Clarke, are genera related to Orbi-
culoidea. Devonian ; North America.

Superfamily 3. CRANIACEA. Waagen.

Cemented calcareous Neotremaia without pedicle or anal openings at maturity.
Ordovician to Recent.

ORDER III

NEOTREMAT A— PROTREMATA

311

Family 1. Craniidae. King.

Crania, Eetzius (Fig. 514). Shell inequivalve, sub-circular in outline. In
the interior of both valves are two pairs of large adductor scars, the posterior
of which are widely separated and often strongly elevated on a central

FIG. 514.

Crania Ignabergensis, Retzius. Uppermost Cretaceous ; Ignaberga, Scania. A, Profile and dorsal aspect of
shell, 1/1. B, C, Interior of ventral valve. D, Interior of dorsal valve, enlarged.

callosity. Impressions of the pallial genital canals coarsely digitate. Ordo-
vician to Recent ; maximum development in Ordovician and Cretaceous.

Craniella, Oehlert. Large Cranias with S-shaped vascular impressions.
(?) Ordovician and Devonian ; North America and Europe.

FIG. 515.

f'l-niiisi'iis rel'/t", Quenst.
Upper Jura; Oerlinger Thai,
Wurtemberg. Interior of
ventral valve, Vl (after
Quenstedt).

FIG. 516.

Ancistrocrania Parisiensis, Defr. Upper Cretaceous ; France.
A, Profile of dorsal valve. B, Interior of same. C, Interior of
ventral valve, Vi-

Craniscus, Dall (Fig. 5^5). Ventral interior divided by septa into three
cavities. Jurassic ; Europe.

Ancistrocrania, Dall (Fig. 516). Dorsal valve with two muscular fulcra.
Cretaceous ; Europe.

Pholidops, Hall (Craniops, Hall). - Biconvex and but slightly attached
Cranias. Ordovician to Carboniferous ; North America, England, Gottland.

Pseudocrania, M'Coy (Palaeocrania, Quenstedt). Radially striated shells
much like Pholidops. Ordovician ; Europe.

Cardinocrania, Waagen. Permian of India.

Order 3. PROTREMATA.' Beecher.

Articulate Brachiopoda, with the pedicle opening restricted to the ventral
valve throughout life or during early growth. Prodeltidittm originating on the
dorsal side of the body wall in the Cephalula stage, and later anchylosed to the ventral
shell, thus initiating the development of a deltidium. Pedicle aperture modified by
the deltidium. Brachia unsupported by a calcareous skeleton except in Pentameracea,
where there are crura.

312 MOLLUSCOIDEA— BRACHIOPODA SUB-KINGDOM v

Superfamily 1. STROPHOMENACEAV Schuchert.

Primitive Protremata without spondylia and cruralia. Cambrian to Recent.

Family 1. Kutorginidae. Schuchert,

Primitive Strophomenacea with incipient cardinal areas, great delthyrium and
very rudimentary articulating processes and deltidium. Cambrian.

Kutorgina, Billings. K. cingulata, as redefined by Walcott, from the
American Lower Cambrian, is the only species positively known to belong to
this family. Schizopholis, Waagen, of the Lower Cambrian in India, and
F'olborthia, Moller, of the Ordovician, may also possibly find a place here.

1 Family 2. Eichwaldiidae. Schuchert.

Primitive or aberrant, rostrate Strophomenacea, with narrow lateral grooves and
ridges for articulation. Delthyrium closed by a concave plate (? deltidium). Pedicle
emerging through the ventral umbone and moving with growth anteriorly by resorption
through the shell, as in Siphonotretidae. Ordovician and Silurian.

Eichwaldia, Billings. The single species of this genus has a smooth
exterior. Ordovician ; North America.

Dictyonella, Hall (Eichwaldia, auct.) Exterior surface of valves pitted in
quincunx, resembling Trematis. Silurian ; North America, England, Bohemia,
and Gottland.

Family 3. Billingsellidae. Schuchert.

Strophomenacea with well-developed cardinal areas and deltidium. Cardinal
process obsolete or very rudimentary. Articulation fairly well developed. Cam-
brian. \

Billingsella, Hall and Clarke (Protorthis, H. and C.) This is the only known
genus of the family, and contains a number of the oldest well-developed
species of Protremata. Cambrian ; North America.

Family 4. Strophomenidae. King.1

Strophomenacea with well-developed cardinal areas, deltidium, chilidium, cardinal,
and articulating processes. Ordovician to Permian.

Piafinesquina, Hall and Clarke (Fig. 517). Shells normally concavo-convex
dorso-ventrally. Striae alternating in size, and crossed by finer concentric
growth lines. Muscular area of ventral valve consisting of two broad flabel-
late diductor scars enclosing an elongate adductor. In the dorsal valve, the
bilobed cardinal process is low ; the posterior arborescent adductor scars
well defined. Vascular and ovarian markings often well indicated. Ordovician;
North America and Europe.

1 [According to J. M. Clarke, a separation into groups of the genera here included under one
family is advisable, according as the shell is normally convex, or reversed convex. The habit of
reversion, originating in the unequal growth of the two valves, characterises a large number of forms,
which stand in a notable degree in successive genetic relationships ; while their affinities witli the
normally convex forms are less palpable. This author is in favour of restricting the Stropkomenufaf
so as to include only those genera in which the shell is usually reversed convex, and employing the
family term Leptaenidae for those having normally convex shells. — TRANS.]

olOKR III

I'lloTlIKMATA

313

Stropheodonta, Hall. Shells very much like Jtiifinesgui-na, but with the
cardinal margins finely denticulate and the deltidium flat or not discernible.
Silurian and Devonian ; North America and Europe.

Leptostrophui, Hall and Clarke; DouvUlina, Oehlert and Brachyprion, Shaler,'

are sub-genera of Str»i>}"'niltntfa. Silurian and Devonian.

Fio. 517.

.1, Ritfinesquina alternata, Conrad sp. Ordovician ; Cincinnati, Oliio.
of ventral valve, showing muscular and vascular impressions.

BJR. expansa, Sow. sp. Interior

Pholidostrophia, Hall and Clarke. Smooth or squamose, nacreous small
Stropheodontae. Devonian ; North America and Europe.

Strophonella, fiall (Amphistrophia, Hall and Clarke). Eesupinate Stropheo-
dontae. Silurian and De-
vonian ; North America and
Europe.

Leptaena, Dalman (Lepta-
fionia, M'Coy), (Fig. 518).
Shells having the characters
of Eafinesquina, but the flatter
portions of the valves with
corrugations and wrinkles.
Where these cease, the shells
are more or less abruptly
and often rectangularly deflected.

FIG. 518.

I^ptaena rhomboidalis, Wahlenb. sp. Silurian ;
A, B, Dorsal aspect and profile. C, Interior of dorsal va

Gottlancl.

Ive.

Fio. 519.

Plectambonites transversal is, Dalm. sp. Silurian ;
Gottland. A, Dorsal aspect, 1/1- •#> Interior of dorsal
valve, 1/1- C, Ventral valve, 3/x. (A, Adductors;
/.', Divaricators).

Leptella, Hall and Clarke.
Lower Ordovician ; North America and England.

Ordovician to Carboniferous.

Cadomelldj Munier-Chalmas. Similar
to Eafinesquina, but in the ventral valve
between the divergent teeth there is a
bowl-shaped muscular apophysis for the
attachment of accessory diductors. The
prominent socket walls of the dorsal
valve continued
apophyses, which
freely.

Plectamlonites, Pander (Leptaena,
Davidson and auct.), (Fig. 519). Ordo-
vician and Silurian ; North America
and Europe. ^
Primitive Plectambonites. Upper Cambrian and

into curved crural
sometimes terminate

314

MOLLUSCOIDEA— BRACHIOPODA

SUB-KINGDOM V

FIG. 520.

Bouchar-
Devonian:

Leptaenisca, Beech er. Ventrally cemented shells having some of the char-
acters of Plectambonites. Markings of the fleshy arms are
retained on the dorsal shell. Silurian ; North America.

Christiania, Hall and Clarke. Differs from Leptaenisca
in having prominent longitudinal ridges instead of spiral
markings on the dorsal interior. Basal Devonian ; North
America, England, and Russia.

Davidsonia, Bouchard (Fig. 520). Thick Leptaenisca-
like shells, with spiral markings of the fleshy arms strongly
impressed on both valves. Devonian ; England, Belgium,
and Russia.
Strophomena, Blainville. Shells like Piafinesquina, but resupinate, or with the

relative convexity of valves reversed, and the ventral muscular area sharply

limited by an elevated margin. Ordovician ;

America and Europe.

Orthothetes, Fischer (Figs. 521, 522).

Much like Strophomena. Shell plano-convex

or biconvex, but becoming concavo-convex

with age. Surface covered with radiat-
ing striae, which are convoluted by sharp

concentric lines. Hinge - line as long or

longer than the greatest width of the shell.

Cardinal area of ventral valve prominently

developed; dorsal area narrow. Cardinal

process united to crural plates, the whole

forming a vertical sub-crescentic process.

Muscular impressions flabelliform. Silurian

to Carboniferous ; North and South America, Europe, and India.

Hipparionyx, Vanuxem. Like Orthothetes, but with the muscular areas

much larger and no dorsal cardinal area. Lower Devonian ; North America.

FIG. 521.

Orthothetes umbmculum, Schloth. sp. De-
vonian ; Gerolstein, Bifel. Natural size.

FIG. 522.

Orthothetes crenistria, Phill. Carboniferous Limestone ; Wexford. A, Muscular portion of ventral valve.
B, Interior of dorsal valve. (A, A', Adductors. R, Diductors ; j, Cardinal process ; d, Dental sockets), (after
Davidson).

Kayserella, Hall and Clarke. Small Orthothetes-like shells, with a very high
dorsal median septum. Devonian ; Germany.

Derbya, Waagen. Like Orthothetes, with a high median septum in the ventral

ORDER in PROTREMATA 315

apex and muscular area, and usually ventrally cemented. Carboniferous;
North and South America, Europe, India, and Russia.

Streptorhynch-us, King. Very much like Derln/n, but without the ventral
septum. Beak acute, incurved, or distorted. Carboniferous and Permian ;
America, .Europe, and India.

Meekella, White and St. John. Very biconvex shells, with the teeth of the
ventral valve supported by septiform dental lamellae, which reach to the
bottom of the umbonal cavity, and extend forward for one-third or one-half
the length of the shell. Surface of valves with coarse costae and fine radiat-
ing, often plumose, striae. Upper Carboniferous; North America, Russia,
India, and China.

Triplecia, Hall (Dicraniscus, Hall). Trilobate, unequally biconvex, short-
hinged shells. Cardinal process long, erect, and bifurcate. Surface of valves
usually smooth, but sometimes striated radially. Ordovician and Silurian ;
North America, England, and Bohemia.

Mimulus, Barrande. Like Triplecia, but with the median fold on the
ventral valve. No external evidence of a deltidium. Silurian ; Bohemia and
North America.

Streptis, Davidson. Like Triplecia, but biconvex and bilaterally unsym-
metrical. Exterior with lamellar concentric shell expansions. Silurian ;
England, Gottland, and North America.

1 Orthidium, Hall and Clarke. Ordovician ; North America.

Family 5. Thecidiidae. Gray.

Cemented Strophomenacea, in which the interior of the shell is impressed with
variously indented brachial furrows. Carboniferous to Recent.

This family was formerly associated with the Terebratulidae. Beecher has shown,
however, that brachial supports are wanting, and that a true deltidium is present.

Lyttonia, Waagen (Leptodus, Kayser). Very large, highly inequivalved,
irregular shells, frequently with
broad lateral expansions. Numer-
ous, laterally directed, brachial
ridges in the ventral valve, with
corresponding divergent grooves
in the median region of the dorsal
valve. Carboniferous ; China and
India.

Oldhamia, Waagen (Fig. 523).
Differs from Lyttonia in that the
ventral valve is sub-hemispherical
with the incurved apex covered

i 11 ., • r> 77 7 Oldhamia decipiens, \\aagen. Prouuctus Limestone; Salt

by a callosity, as in Bellerophon. Range, East India. A, B, Interior of ventral and dorsal

Carboniferous ; India and China. valves> resi>ective]y <after Waage»>-

Thecidea, Def ranee (Thecidium, Sowerby), (Fig. 524). Dorsal brachial
impressions with three pairs of symmetrical lobes, radially directed. Cretaceous.

Thecidea and the following genera of the family Thecidiidae comprise for the most
part small, sometimes extremely minute forms, represented from the Trias to the
present day ; the climax of diversity occurred in the Cretaceous.

316 MOLLUSCOIDEA— BRACHIOPODA SUB-KINGDOM v

Lacazella, Munier-Chalmas (Figs. 525, 526). Dorsal brachial impressions

FIG. 524.

Thecidea papillate, Schloth.
Cretaceous; Ciply, Belgium. A, B,
terior of ventral and dorsal valves, re-
spectively, 2/i (after Woodward).

FIG. 525.

Lacazella vermicularis,
Schloth. sp. Upper Creta-
ceous ; Maestricht. Dorsal
valve, 2/j (after Suess).

FIG. 526.

Lacazella Me. 'I ltd
ranea, Risso. Recent-
Interior of dorsal
valve showing
brachia, 2/j (after
Woodward).

with two or three unequal pairs of lobes, medially directed. Jurassic to
Recent ; Europe.

Thecidiopsis, Munier-Chalmas (Fig. 527). The two, large, dorsal, brachial
impressions each have four pairs of lobes laterally and medially directed.
Cretaceous ; Europe.

Thecidella, Munier-Chalmas. Dorsal brachial impressions simple, anteriorly
directed. Jurassic ; Europe.

Eudesella, Munier-Chalmas. Transverse shells in which the dorsal brachial

FIG. 527.

Thecldiopais digitata, Goldf. Greensand ; Essen on the
Rhine. A, Dorsal aspect. B, C, Interior of ventral and
dorsal valves, respectively, 1/1-

FIG. 52S.

Pterophloios Emmrichi, Giimbel.
Rhaetic ; Kossen, Tyrol. In-
terior of dorsal valve, 1/1-

impressions have three pairs of simple lobss antero-laterally directed. Jurassic;
Europe.

Pterophloios, Giimbel (Bactrynium, Emmrich), (Fig. 528). Dorsal brachial
impressions with about ten laterally directed lobations. Alpine Rhaetic.

Davidsonella, Munier-Chalmas. Elongate shells with the long, narrow,
dorsal, brachia] impressions simple and antero-laterally directed. Jurassic ;
Europe.

Family 6. Productidae. Gray.

Strophomenacea with hollow anchoring spines, Silurian to Permian.

Chonetes, Fischer (Fig. 529). Shell transversely elongate, semi-circular in
outline, normally concavo-convex, sometimes plano-convex. Upper margin of
cardinal area in ventral valve bearing a single row of hollow spines ; these are
prolongations of tubes which penetrate obliquely the substance of the shell
along the hinge-line. Teeth strong. Cardinal process of dorsal valve divided
by a narrow median and twro broader lateral grooves. Brachial impressions
more or less distinct. External surface usually covered with radiating striae,
rarely smooth or concentrically rugose. Silurian to Permo-Carboniferous.

Anoplia, Hall and Clarke. Smooth or squamose shells like Chonetes, sup-
posed to be without cardinal spines. Lower Devonian.

OllDElt III

PROTHEMATA

317

( '/tonostrophia, Hall and Clarke. Like Chonetes, but with the shell reversed
or concavo-convex. Lower and Middle Devonian ; North and South America.

Chonetelltt, \Vaagi-n. Upper
Carboniferous ; India. Chonetina,
Krotow. Permian ; Russia.

Chonopectnx, Hall and Clarke.
Chonetes-like shells, but cemented
ventrally to extraneous objects.
External surface reticulated by a
double, oblique series of concentric
lines and fine radiating striae.
Lower Carboniferous ; North
America.

Strophalosia, King (Orthothrix,

Geillitz; Leptaewlosia, King), (Fig. A.ChrnietesgMotella.D&lm.ap. Silurian ; Gottlaud. J/,.

530). Shell Productoid in general £, {"tenor of dorsal valve of OumetoMtiu Davidson).

' C, C. sa.rci tnilata, de Kon. Devonian ; Coblenz. 1/1-

form, cemented by the ventral

umbo. Both valves with well-defined area and deltidium. Ventral valve
with two prominent teeth unsupported by lamellae. Muscular impressions
small ; brachial ridges distinct. Surface of ventral valve covered with spines ;
that of the dorsal valve either spinous, lamellose, or smooth. Middle
Devonian to Permian ; Europe, India, North and South America.

Aulosteges, Helmersen. Much like Strophalosia, but not cemented by the

FIG. 529.
A, Chonetes striatella, Dalin. sp. Silurian ; Gottlaud. 1/1-

FIG. 530.

Strophalosia Goldfussi, Miinst. sp. Permian ; Gera, Reuss.
A, Dorsal aspect. B, Profile. C, Cast of dorsal valve with brachial
impressions. Natural size.

FIG. 531.

Produclus horridus, Sow.
Permian ; Gera, Reuss. 1/4-

ventral umbo ; deltidium covered with small spinules and the surface of both
valves thickly set with spines. Permian ; Russia and India.

Productella, Hall. Shells small, Productoid, with narrow cardinal areas in
both valves. Ventral valve with small teeth ; dorsal valve with sockets and
crural plates. Brachial impressions distinct. Devonian.

Productus, Sowerby (Pyxis, Chemnitz ; Arlusculites, Murray; Protonia, Linck ;
Marginifera, Waagen), (Figs. 531, 532). Shell without functional pedicle,
probably anchored by the ventral spines ; concavo-convex, valves usually
produced anteriorly ; outlines semi-circular, sometimes transversely elongate.
External surface usually with more or less prominent radiating ribs, which
are crossed by concentric lines or wrinkles ; rarely smooth or finely striated.
Cardinal areas, teeth, sockets, and crural plates absent or rudimentary. Ventral
valve convex, sometimes geniculated ; occasionally with median sinus. Muscular
impressions consisting of two dendritic adductors and a pair of broadly flabel-
late, striate diductors ; traces of spiral or brachial cavities occasionally

318

MOLLUSCOIDEA— BRACHIOPODA

SUB-KINGDOM V

present in the pallial region. Cardinal process strong, curved, or erect, extend-
ing far above the hinge-line. Brachial ridges well defined. Extraordinarily
abundant in Carboniferous and Permian. Distribution general.

P. giganteus is the largest Brachiopod known, sometimes attaining a width of nearly
one foot.

Proboscidella, Oehlert. Valves very unequal ; dorsal valve small, concave,
operculiform ; ventral valve larger, convex, furnished with two lateral expan-
sions which bend downward to meet the margins of the dorsal valve, and an

FIG. 532.

A, Productus semireticulatus, Martin. Carboniferous Limestone ; Vise, Belgium. 1/1- -B> P- giganteus.
Martin sp. Same horizon ; England. Interior of dorsal valve (after Woodward). C, D, P. horridus, Sow.
Permian ; Prussia and England. !/!• C, Interior of dorsal valve. D, Cast of ventral valve (A, Adductors ;
R, Diductors ; pr, Cardinal process ; h, Hinge-line ; v, Brachial impressions).

anterior expansion, which is produced forward into one, or occasionally two,
long, cylindrical tubes. Carboniferous ; Europe and North America.

Stheridgina, Oehlert. Shell very small, nearly as broad as long, and
attached to foreign bodies, notably Crinoids, by the spines of the ventral
valve. Dorsal valve with a small beak ; surface ornamented by concentric
flexuous plications bearing a few scattered spines. Carboniferous ; Scotland.

1 Daviesiella, Waagen. Shell Productoid, but without spines and well-
developed cardinal area and teeth. England.

1 Aulacorhynchus, Dittmar (Isogramma, Meek and Worthen). Very large,
transverse, thin shells with a ventral platform. Exterior surface with numerous,
regular, continuous, concentric ridges. Upper Carboniferous ; Europe and
North America.

Family 7. Bichthofenidae. Waagen.

Strophomenacea, probably derived through the Productidae, and remarkably modified
by ventral cementation. The form is that of Cyathophylloid corals with an operculiform
dorsal valve. Shell structure cystose.

ORDER III

]'i;oTi;i-:.MATA

319

JUrhthofenia, Kayser (Fig. 533). These most remarkable modified Brachio-
pods are found in the Permo-Carboniferous of China and

linlia.

Family 8. Orthidae. Woodward.

Strophomenacea usually with large open delthyria ; deltidium
developed only in younger growth stages. Ordovician to
Permian.

Orthis, Dalman (Orllminlxmites, Pander), (Figs. 534-536).
Shell sub-quadrate to sub-circular in outline; surface
covered with radiating striae or costae. Valves more or
less convex ; the small or dorsal valves sometimes nearly
flat or slightly concave. Cardinal areas well developed in
both valves, and usually divided by open delthyria. Hinge-
teeth large, and supported by well-developed dental plates.
Dental sockets of dorsal valve deep, their inner walls
supporting short divergent crura. Median ridges fre-
quently present in both valves. Vascular markings often
retained. Ordovician to Carboniferous ; particularly abundant in the Ordo-

Fio. 533.

Richthofenia Lawrenci-
an«,Waagen. Penno-Car-
bon.; Salt Range. Y.-rtiral
section of ventral valve
(after Waagen).

FIG. 534.

A~C, Orthis (Schizophoria) striatula, Schloth. sp. Devonian ; Gerolstein, Eifel. A, Dorsal aspect. E, Interior
of dorsal valve. C, Interior of ventral valve. D, Orthis vulvaria, Schloth. Spiriferensandstein ; Niederlahn-
stein, Nassau. (All figures of the natural size.)

FIG. 535.

Orthis (Dalmanella) elegantuta,
Dalni. Silurian ; Gottlaud. i/j.

FIG. 537.
riutystrophia lynx, Eichw. Ordoviciau ; Cincinnati, Ohio. 1/1-

vician and Silurian, which have alone yielded about
^HR /,« ^0 species. Distribution general.

ft vmy^ijjij This genus has been recentlv divided ^y Hal1 and

^ ^^ Clarke into fifteen sub-genera, as follows : — Orthis s.s.,

Plectorthis, Dinorthis, Plaesiomys, Hebertella, Orthostrophia,
Platystrophia, King (Fig. 537), Heterorthis, Bilobites,
Linne (Fig. 536), Dalmanella (Fig. 535), Rhipidomcll',
Oehlert, Schizophoria, King (Fig. 534), Orthotichia,
Enteletes, Fischer de Waldheim, and Orthotropia.

FIG. 536.

Orthis (BiloUtes) Uloba,
Lin. Silurian ; Gottland. A,
Shell, 1/1. B, Interior of dorsal
valve, 2/1.

320

MOLLUSCOIDEA— BRACHIOPODA

SUB-KINGDOM V

Superfamily 2. PENTAMERACEA. Schuchert.

Derived Protremata with spondylia, to which are attached the adductor, diductor,
and ventral pedicle muscles. Cruralia commonly pi'esent. Ordovician to Permian.

Family 1. Clitambonitidae. Winchell and Schuchert.

Primitive Pentameracea with long, straight cardinal areas and a well-developed
deltidium. No cruralium. Ordovician to Devonian.

Clitambonites, Pander (Orthisina, d'Orb., Pronites, Hemipi-onites, and Gomi.m-
bonites, Pander), (Fig. 538). Valves convex or sub -pyramidal. Hinge-line
straight, forming the greatest diameter of the shell. Cardinal area of the

ventral valve high ;
delthyrium broad,
and covered by a
perforate deltidium ;
that of the dorsal
valve covered by a
chilidium. Dental
lamellae of ventral
valve very strongly
FlG' 53S' developed, uniting

A, Orthisina adscemtens, Pand. Ordovician ; Pawlowsk, near St. Petersburg. » J

i/i. B, C, 0. squamata, Pahlen. Ordovician ; Kuckers, Esthonia. B, Interior of tO lOrm a COllCave

dorsal valve, showing edge of the chilidium. C, Interior of ventral valve, showing ar,of nlofa -nlafp or
spondylium, septum, and deltidium (after Pahlen).

spondylium. This

plate serves for the attachment of muscles, and is supported by a median
septum extending for about one-half the length of the valve. External
surface radially striated. Shell substance impunctate. Ordovician ; Russia,
England, and North America.

Polyfoechia, Hall and Clarke. Like Orthisina, but with the spondylia sup-
ported by three septa, thus dividing the umbonal cavity of the ventral valve
into five chambers. Ordovician ; North America.

Scenidium, Hall (Mystrophora, Kayser). Small Orthisinoid shells with the
delthyrium partially closed by a concave imperforate deltidium. Cardinal
process extending as a median septum throughout the length of the shell.
The septum is sometimes greatly elevated anteriorly in Devonian species.
Ordovician to Devonian ; North America, Europe, and the Urals.

Family 2. Syntrophiidae. Schuchert.

Primitive Pentameracea with long, straight cardinal areas, deltidia, and cruralia.
Lowest Ordovician.

Syntrophia, Hall and Clarke. Transverse, straight - hinged, primitive
Pentameroids. North America.

Family 3. Porambonitidae. Davidson.

Pentameracea intermediate in structure between the Syntrophiidae and Penta-
meridae ; the deltidium ana the straight cardinal areas of the former family tending
to obsolescence, particularly the deltidium. The Porambonitidae approach the latter

ORDER III

PROTREMATA

321

in tending to develop a rostmfr ^<-iL <'r>i<-»lutm present. Ordovician to
Lower Devonian.

Camarella (Billings), Hall and Clarke. Small smooth shells with a few low
])lications and without cardinal areas. Dorsal valve at maturity most convex.
Spondylium well defined. Cruralium very small, supj)orted by a long septum.
Ordovician ; North America and (?) England.

/V/VS//VY//,,,,, Hall and Clarke. Much like Camarella, but with a moderately
long, straight, cardinal line, and no cardinal area. Dorsal umbo conspicuous,
projecting beyond that of the ventral valve. Ordovician and Silurian; North
America and England.

Anastrophia, Hall (Brachymerus, Shaler, non Dej.) Much like Parastrophia,
but with the dorsal umbo more prominent and the valves with numerous sharp

FIG. 539.

Porambonites wqnirostris, Schloth. sp. Ordovician (Vaginateukalk) ; St. Petersburg. A~C, Anterior, lateral,
iiinl IM Verier aspects of shell, Vi- A Punctate surface, magnified. E, F, Interior of ventral and dorsal valves,
respectively.

plications extending to the beaks. Silurian and Lower Devonian ; North
America, England, and Gottland.

Porambonites, Pander (Is&rhynchuSj King), (Fig. 539). Shells similar to
Parastrophia in form, but without plications, and with obtusely triangular
areas in both valves. Shells thick, variously pitted externally. Ordovician ;
Russia.

Noetlingia, Hall and Clarke. Exterior like Porambonites, but with long,
straight, hinge-line, prominent cardinal areas, and perforate beaks. Ordovician ;
Russia.

? Lycophoria, Lahusen. Russia and Scandinavia.

Family 4. Pentameridae. M'Coy.

Rostrate Pentameracea rarely with straight cardinal areas. Deltidium commonly
absent, but sometimes present as a concave plate, being the reverse of the ordinary form
of the deltidium and due to the incurved beaks. Cruralium present. Silurian to
Permian.

Conchidium, Linn£ (Gypidia, Dalman ; Antirhynchonella, Quenstedt ; Zd'nnir,
Barrande), (Fig. 540). Shell strongly iiiequivalve, biconvex, with highly
arched ventral valve. Surface numerously plicated. Spondylium narrow and
deep, and supported by a high vertical septum of variable length. A small
cardinal process present. Silurian and Devonian ; distribution general.

Stricklandinia, Billings. Similar to Conchidium, but with a straight hinge-
line and no prominent arched ventral beak. Spondylium small and short,
supported by a short median septum. Silurian ; North America, England,
and Gottland.

Pentamerus, Sowerby (Pentastere, Blainville). Like Conchidium, but with
VOL. i Y

322

MOLLUSCOIDEA— BRACHIOPODA

SUB-KINGDOM V

smooth shells, or sometimes with a few broad and obscure radiating undula-
tions. Silurian ; distribution probably general.

Capellinia, Hall and Clarke. Like Pentamerus, but with the relative con-
vexity of the valves reversed. North America.

Clorinda, Barrande (Barrandella, Hall and Clarke). Small galeatiform

FIG. 540.

Conchidium bilociilare, Linn. Silurian ; Gottland. A, Shell of the natural size. B, Beak showing concave
deltidium. C, D, Interior of dorsal and ventral valves, respectively (x, Spondylium ; S, Median septum of
ventral valve, Fig. D; l>, Dental lamellae ; c, Crura ; S, Septum-like supports, Fig. C).

Pentameroids usually with smooth shells, rarely plicate. Spondylium with-
out a supporting septum. Silurian ; North America and Europe.

Pentamerella, Hall. Much like Clorinda, but with strong plications and a
narrow cardinal area. Devonian ; North America.

Gypidula, Hall (Sieberella, Oehlert), (Fig. 541). Galeatiform Pentameroids,
with the median sinus on the dorsal, and the fold on the ventral valve. In

FIG. 541.

A-C, Gypidula galeata, Dalm. sp. Devonian ; Gerolstein, Eifel. A, Dorsal aspect, Vi- -B, Anterior aspect.
C, Transverse section below the hinge-line. (Lettering the same as in Fig. 540 C, D.) D Conchidium Knightii,
Sow. Silurian ; England. 1/2-

Sieberella there is no cardinal area, but in typical Gypidula there is a well-
defined, cross-striated, cardinal area. Surface smooth or plicate Silurian
and Devonian ; North America and Europe.

Amphigenia, Hall (Enantiosphen, Whidborne). Elongate - ovate, high-
shouldered shells without median fold or sinus. Surface with concentric
growth varices and faint radial striae. Dorsal valve with a large sub-quadrate
hinge -plate perforated by the visceral foramen and without a cruralium.
Middle Devonian ; North and South America, France, and Germany.

Camarophoria, King (Fig. 542). Shells Ehynchonelliform with the surface

ORDER IV

TELOTREMATA

323

more or less strongly plicated. Spondylium supported by a long median
septum. Devonian to Permian ;
Europe, India, and North America.

Camarophorella, Hall and Clarke.
Biconvex, sub-circular Camarophvrinf,
but without sinus, fold, and plica-
tions. Lower Carboniferous ; North
America.

Order 4. TELOTREMATA.
Beecher.

Flo.

> .. 7 . T> -L • T -jt ji Cdimirophorifi Schlothfiml, v. Hue):. I'l-niiian ; Gera,

Articulate JBmchlOpoda, With the RCUSS. /, Shell, Vi- It, Cast. C, Interior of shell, en-
nnonjnn ahnrcil hu JtnfJi vnlrp* in 1{ir«eil 0"% Cardinal process ; o, Cnim ; ./, Spoiidylium ;

opening snared t>y oom waves in (J< Dentalplates of dorsai valvtj; ,,,.-, Meiliai.
nepionic and early neanic stages, usually

confined to one valve in later stages, and becoming more or less modified by deltidial
plates in ephebic stages. Brachia supported by calcareous crura, loops, or spiralia.
Prodeltidium ubsent.

Superfamily 1. RHYNCHONELLACEA. Schuchert.
Rostrate, primitive Telotremata, ivith or without crura. Cambrian to Recent.

Family 1. Protorhynchidae. Schuchert.

Primitive Ehynchonellacea without' deltidial plates or crura. Cambrian and
Ordovician.

Protorhyncha, Hall and Clarke. Biconvex PJiynchonellae with the fold
and sinus ill-defined. No cardinal process or dorsal median septum. Surface
with low radial plications. Ordovician.

There are smooth-shelled, very primitive PJiynchonellae in the American
Lower Cambrian belonging to this family.

Family 2. Rhynchonellidae. Gray.

Ehynchonellacea with crura of greater or lesser length. Ordovician to Recent.

Orthorhynchula, Hall and Clarke. Pihynchonellae with short straight hinge-
line and cardinal areas in both valves, bisected mesially by open delthyria.
External surface plicate. Teeth unsupported by dental lamellae. A linear
cardinal process present. Ordovician ; North America.

Rhynchotrema, Hall (Stenochisma, Conrad, 1839; and Hall, 1867). Thick-
shelled, often gibbous Pihynchonellae with prominent, thick, concave deltidial
plates. Dorsal valve with a thick median septum, upon which rests a linear
cardinal process. Crural plates very broad and stout. Ordovician to
Devonian ; North America.

Rhynchotreta, Hall. Trihedral Rhynchonellae with the ventral beak acu-
minate and produced. Pedicle foramen apical, the delthyrium being com-
pletely closed by the deltidial plates. Dental lamellae and cardinal process
present. The prominent dorsal median septum separates posteriorly, each

324 MOLLUSCOIDEA— BRACHIOPODA SUB-KINGDOM v

branch supporting one process of the divided hinge-plate. Silurian ; North
America and Europe.

Camarotoechia, Hall and Clarke (Plethorhyncha, H. and C.) MhynchoneUae
.with the dorsal median septum bearing posteriorly an elongate cavity.
Cardinal process absent ; dental lamellae present. Ordovician to Carboni-
ferous ; North America andt Europe.

Leiorhynchus, Hall. Like Camarotoechia, but with the plications on the
lateral slopes usually faint or obsolete. Devonian to Carboniferous.

JPUsonia, Kayser (Uncinulina, Bayle). Sub-cuboidal or sub-pentahedral
Rhynchonellae with the low plications marked anteriorly by fine median lines.
Dental lamellae present. No cardinal process. Silurian and Devonian ;
North America and Europe.

Uncinulus, Bayle. Like IFilsonia, but with the hinge-plate undivided, and
with a well-developed cardinal process. Devonian; North America and Europe.

Hypothyris, King. Sub-cuboidal Rhynchonellae with a very rudimentary
dorsal median septum. Plications as in Wilsonia. Vascular sinus frequently
strongly impressed in the ventral valve. Devonian ; Jforth America and
Europe.

Pugnax, Hall and Clarke. PJiynchonellae with a deep dorsal and shallow
ventral valve, and very prominent fold and sinus ; otherwise resembling
Hypothyris. Devonian to Carboniferous ; North America and Europe.

Eato-nia, Hall. Pihynchonellae with large, flabellate, deeply excavated
muscular scars in the ventral valve. No dental lamellae. Cardinal process
large, resting upon a short median septum, and bifurcate at its summit.
Devonian ; North America.

Terebratuloidea, Waagen. PJiynchonellae with very large apical foramen,
but without dental plates, cardinal process, or median septa. Carboniferous
to Permian ; India.

Rhynchopora, King (PJiynchoporina, Oehlert). Plicate Pihynchonellae with
the shell substance punctate. Carboniferous to Permian ; Europe and North
America.

Rhynchmetta, Fischer (as restricted by Hall and Clarke), (Fig. 543, A).
Sub-pyramidal shells with a prominent anterior linguiform extension. Dental
lamellae and a dorsal median septum present. No cardinal process. Jurassic
and Cretaceous.

Upwards of 600 species of Rhynchonella have been described, most of which
are found in Mesozoic strata (Figs. 543, B, 544). It is probable that but few of these
agree with the "type species, R. loxia, from the Upper Jura of Russia. Hall and Clarke
have shown that many American Palaeozoic species belong to other genera ; and Bittner
has also removed from Rhynchonella many Triassic species. It is probable that no
Palaeozoic Rhynchonellae s.s. exist.

Halorella, Bittner. Sharply plicated Rhynchonellae with a median sinus on
both valves. Alpine Trias.

Austriella, Bittner. Small triangular, usually smooth-shelled Rhynchonellae
without prominent fold and sinus. Alpine Trias.

Norella, Bittner. Like Austriella, but with prominent anterior fold and
sinus. Alpine Trias.

Rhynchonellina, Gemellaro. Transverse Rhynchonellae with fine rad'
striae. Cardinal margin nearly straight, with a low concave ventral

TELOTREMATA

325

(Ynra very long, ventrally curved. Median septum of dorsal valve faint.
•I ura ; Sicily ami tin- Alps.

i., Zittel. Small plicate shells with a high umbo and a straight

Fie;. 543.

A, rJn/itchonclla loxia, Fisch. Upper Jura ; Moscow, a, 7), Profile
and dorsal view, l/i ; c, Cast ; d, Anterior view. B, R. quadri'plicata,
Quenst. Middle Jura ; Boptingen, Wiirtemberg.

A,

Brocchi. Upper Cretaceous ;
Villedieu, Touraine. 1/1- B, R.
lacunota, Schloth. sp. Upper
Jura ; Engelhardsberg, Francdhia.
Interior of dorsal valve.

hinge-line. Delthyrium large, with linear deltidial plates. Dorsal valve
with a high median septum extending to the ventral valve. Alpine Trias.

Peregrinella, Oehlert. Large, strongly plicate Rliynclwnellae without fold
or sinus. Cardinal area well
developed. Cretaceous;
Europe.

Hemithyris, d'Orb. (Fig.
545). Smooth or faintly
plicate Khynchonellae with a
high ventral beak and open
delthyrium. No dental
plates. Recent.

Fio. 545.

•n • i • T\ 11 t> ]I' '""'"' '•"'''•"' ]'»<tf'"'<'" ,Lam. sp.

Fnelem, Dall. Resem- Mediterranean. Vi-

Schloth. sp. Middle
Jura; AaeroaoK. Upper
Palatinate.

bling Fjfmithyris, but with a

small dorsal spondylium. Recent ; American Pacific.

Acanthothyris, d'Orb. (Fig. 546). Like the last, but with well-developed
dental plates, and the exterior surface covered with spines. Jura to Recent ;
Europe and Japanese Province.

( 'ri//>fn/H>ra, Jeffreys (Atretia, Jeffreys ; Neatretia, Oehlert). Small smooth
shells with an acute and prominent open ventral beak. Dental plates and
a high, mesially situated, dorsal septum present. Recent.

Cydorhina, Hall and Clarke. Devonian ; North America.

Superfamily 2. TEREBRATULACEA. Waagen.

Derived Telotremata with the brachia supported ly calcareous, primitive, or meta-
morphosed loops. Devonian to Recent.

3:26 MOLLUSCOIDEA— BRACHIOPODA SUB-KINGDOM v

(SECTION A.) TEREBRATULA..

Terebi-atulacea with the loops unsupported by a median doi'sal septum at any stage
of growth. Brachial cirri directed outwards in larval stages.

Family 1. Centronellidae. Hall and Clarke.

Terebratulas with the loops developing direct and composed of two descending
lamellae, uniting in the median line and forming a broad arched plate. Devonian
to Triassic.

This family comprises the simplest of all Terebratuloids, and from it are probably
descended the other loop-bearing families.

Centronella, Billings (Fig. 547). Commonly small, smooth, plano-convex,
or concavo-convex shells, with the descending branches of the loop broadening
rapidly anteriorly, and uniting in a triangular, mesially ridged plate.
Devonian ; North America.

Bensselaeria, Hall. Ovate or elongate-ovate striate Terebratuloids. The
descending branches of the loop diverging for a short distance, thence acutely
bent, converging, and uniting in an elongate triangular plate, which on the

posterior margin gives off a small, pos-
teriorly directed, rod-like process. Hinge-
plate large and often much thickened.
Thick dental plates present. Lower
Devonian ; North America and Germany.
Beachia, Hall and Clarke. Lentiform
finely striated Eensselaeriae with the
lateral margins of the valves inflected,
the anterior plate of the brachidium

Centronella glans-fa^H^l. Devonian ; Erie broader, and the rod-like prOCCSS longer.

County, N.Y. A, B, Profile and dorsal aspect, 1/1- Lower Devonian ; North America.

Newberria, Hall (fiensselandia, Hall).

Resembling Piensselaeria externally, but without the striate surface. Interior
strongly marked by muscular scars and vascular sinuses. Devonian ; North
America and Europe.

Oriskania, Hall and Clarke. Large Centronellae with a continuous hinge-
plate bearing a thin vertical spur or cardinal process. Lower Devonian ;
North America.

Selenella, Hall and Clarke. Biconvex Terebratuliform shells with a
Centronella-like loop, but the triangular plate not mesially thickened. De-
vonian ; North America.

Eomingerina, Hall and Clarke. Small biconvex Centronellae with the
median ridge on the anterior plate of the loop elevated into a high vertical
lamella almost touching the ventral valve and extended both anteriorly
and posteriorly. Devonian to Lower Carboniferous ; North America.

Trigeria (Bayle), Hall and Clarke. Plicated, plano-convex Centronellae.
Devonian ; France, Brazil, and North America.

? Scaphiocoelia, Whitfield. Very large, plicate, piano- or concavo-convex,
Centronella-like, shells exteriorly. Loop unknown. Shell substance fibrous,
impunctate. (?) Devonian ; South America.

ORDER IV

TELOTREMATA

327

Juvavella, Bittner. Small, smooth, biconvex shells, with a very short
CentronellaAike loop. Alpine Trias.

Nucleatula, Bittner. Like Juvavella, but having a longer loop with a well-
developed and fimbriated vertical median plate. Alpine Trias.

Dirutrella, Bittner. Alpine Trias. Chascothyris, Holzapfel. Devonian;
Germany.

Family 2. Terebratulidae. Gray.

Terebratulas developing originally a Centronella-liJce loop, and thence by a short
series of metamorphoses resulting at maturity in a free loop of varying form.
Devonian to Kecent.

STRINGOCEPHALINAE. Dall.

Sub-Family A.

Terebratulidae with a long loop, foil
recurved in front. Probably no median coiled arm.

margin of the dorsal

not

FIG. 548.

Stringoctphalus Burtini, Defr. Devonian; Paffratli, near Cologne. A, Side-view, % natural size. J3, Greatly
reduced diagram showing hraohidium and median septa. C, Young specimen with large delthyrium and deltidial
plates. D, Interior of dorsal valve, natural size, partly restored (a, Adductors ; c, Crura ; d, Dental sockets ;
I, Loop ; pr, Cardinal process ; s, Median septum).

Stringocephalus, Defr. (Fig. 548). Devonian ; Europe and North America.

Sub-Family B. MEGALANTERINAE. Waagen.

Terel/ratulidae with a long loop giving off ascending branches. Devonian to
Carboniferous.

Megalanteris, Oehlert (Meganteris, Suess). Large, smooth, equally biconvex,
sub-oval shells, with the long convergent jugal processes of the loop extending
beyond the connecting band of the ascending branches. Devonian ; Europe
and North America.

Cryptonella, Hall. Elongate oval shells with short jugal processes.
Devonian to Lower Carboniferous ; North America, England, and Bohemia.

328

MOLLUSCOIDEA— BRACHIOPODA

SUB-KINGDOM V

Harttina, Hall and Clarke. Centronclla-]ike shells with a high dorsal
median septum and the descending branches of the loop laterally fringed with
irregularly set spinules. Carboniferous ; North America and Brazil.

? Cryptacanthia, White tand St. John. Upper Carboniferous ; North
America.

Sub-Family C. TEREBRATULINAE. Dall.

A median un\

coiled arm exists in recent

Terebratulidae with a short loop,
genera. Devonian to Recent.

Of this large sub-family only a few of the more important genera can be briefly
considered here.

Dielasma, King (Epithyris, King), (Fig. 549). To the divergent crural
plates is attached a shallow, often quite long, anteriorly acuminate hinge-

FIG. 549.

Dielasma elongata, Schloth. sp. Permian ; Hum-
bleton, England. A, Dorsal and anterior views,
Vl- -B, Interior of conjoined valves, greatly en-
larged (after Davidson).

FIG. 550.

Terebratulina sub-
striata, Schloth. sp.
Upper Jura ; Nat-
theim, Wiirtem-
berg. l/i.

FIG. 551.

Terebratiila Phillipsi,
Morris. Middle Jura ; Eg£,
near Aarau, Switzerland, i/j.

Devonian to Permian ;

plate carrying the muscles of the dorsal valve.
Europe, India, and America.

Eunella and Cranaena, Hall and Clarke. Dielasmas without the adherent
myiferous hinge - plate. Devonian ; North
America.

• Beecheria, Hall and Clarke. Smooth-shelled
Dielasmas without dental plates, but with the

FIG. 552.
Liothyrinu vitrea, Linn. sp. Recent ; Mediterranean. 1/1-

FIG. 553.

Pygope, diphya, Colonna. Tithonian;
Trent, Tyrol. 1/1-

myiferous plate wholly attached to the dorsal valve. Carboniferous ; North
America and India.

Dielasmina, Waagen. Plicated Dielasmas. Carboniferous ; India.

ORDER IV

TELOTREMATA

329

'i, Waagen. Plicated Dielasmas without dental plates.
Carboniferous to Permian ; India.

Xntntlun-h, Waagen. Carboniferous; India Terebratulina, d'Orbigny^
(Fig. 550). Jura to Recent. Distribution general.

Terebratula, Klein, 1753 (Fig. 551). Genus not well known. Mesozoic or
Tertiary.

Liothyrina, Oehlert (Liothyris, Douville), (Fig. 552). Tertiary to Recent.

FIG. 554.

nictu«tlnii-'i* r.xirctata, Park sp. Great Oolite; Bath, England. A-C,
Three views of the natural size. D, Portion of outer surface, enlarged.

PIG. 555.

Glossothyris nucleata, Schloth.
sp. Upper Jura;
Franconia. J/i-

Pygope, Link (DiphyUes,Schroter', Pugites, de Hann; Antinomia, Catullo), (Fig.
553). Shell originally bilobed, the two lobes often uniting anteriorly in
adult specimens, but leaving posteriorly a median hollow space passing
through the shell. Jura ; Europe.

Dictyothyris, Douville (Fig. 554); Glossothyris, Douville (Fig. 555);
(?) Disculina, Deslong. All from the European Jura.

Zui/nieyeria and Pthaetina, Waagen ; and Propygope, Bittner. Trias ; Europe.

Sub-Family D. DISCOLIINAE. Beecher.

Terelmtulidae with the loop short ami no coiled median arm. (?) Cretaceous,
Recent.

Discolia and Eucalathis, Fischer and Oehlert. Recent.
? Agulhasia, King. Small Terebratulika-likQ. shells with the ventral beak
greatly elevated and a triangular false cardinal area, Cretaceous to Recent.

(SECTION B.) TEREBRATELLA.

Terelratulacea with the loop s//yy/ W />// a median dorsal septum throughout life,
or only in the younger stages. Brachial cirri directed inwards during larval stages.
This section has two phyla having a common origin, now geographically separated in
two provinces, one austral, the other boreal.

Family 1. Terebratellidae. King (emend. Beecher).

Terebratulacea with the loop in the higher genera composed of two primary and
two secondary lamellae, passing through a series of distinct metamorphoses while
attached to a dorsal septum. Devonian to Recent.

330

MOLLUSCOIDEA— BRACHIOPODA

SUB-KINGDOM V

Sub-Family A. TROPIDOLEPTIINAE. Schuchert.

Terebratellidae with the loop consisting of two slender descending branches, uniting
with a high, vertical septum. Devonian.

Tropidoleptus, Hall. Plano-convex plicated shells with a long straight
and narrow cardinal area. Teeth and dental sockets corrugated on their
outer surfaces. Devonian ; America, Europe, and South Africa.

Sub-Family B. MEGATHYRINAE. Ball (emend. Beecher).

Terebratellidae in which the loop is composed of descending branches only, passing
in the highest genus through stages correlative with Gwynia, Cistella, and Megathyris.
The lower genera do not complete the series. The original stock for the two following
sub-families. Jurassic to Recent.

Gwynia, King. Minute, elongate - oval, smooth shells with a short,

nearly straight hinge-line. Neither
septa nor loop. Brachia primitive,
consisting of a circlet of cirri.
Recent.

.Zellania, Moore. Minute shells
without a loop, but with a median
septum in each valve. Lias ; Europe.
,.557. Cistella, Gray (Fig. 556). Ex-

ternally like Megathyris, but without
lateral septa. Cretaceous to Recent ;
Europe.

Megathyris, d'Orbigny (Argiope, Deslong.), (Fig. 557). Transversely elon-
gate, plicate, shells with long and straight hinge-line. Dorsal valve with
three or five septa, causing the brachidium to have four lobes. Jura to
Recent ; Europe.

Sub-Family C. DALLININAE. Beecher.

Terebratellidae with the loop composed of descending and ascending lamellae,

d m passing in the

highest genera
through metamor-
phoses comparable
to the adult struc-
ture of Platidia,
Ismenia, Muehl-
feldtia, Terebrat-
alia, and Dallina.
The lower genera,
FIG. 550. therefore, do not

Muehlfddtia truncata, Gemm. sp. >nrnnr/><s<i tn HIP final
Recent; Mediterranean. Interior P^°^esstc

stages.

FIG. 556.

Cistella Ulocu-
laris, Desl. sp.
Cenomanian ; La
Manche. 1/1-

Megathyris decollata, Chem. sp.
Recent ; Mediterranean. Interior
of dorsal valve, 4/i (after Davidson).

FIG. 558.

Muehlfeldtia pectimculvs, Schloth. sp. Upper
Jura'; Engelhardsberg, Fjranconia. A-C, Shell
of the natural size,
enlarged.

Jura to

D, E, Two views of loop,

of dorsal valve (c, Crura ; d, Dental

sockets ; e, Jugum ; /, I, Ascending -,-,

and descending branches of loop ; XvCCent.

p, Process attached to median apnf>rst rpafrirtprl

septum; pr, Cardinal process; S, geneia- >-(

Median septum). ^0 boreal

Platidia, Costa (Morrisia, Davidson). Small, smooth, biconvex shells with

ORDER IV

TELOTREMATA

a large pedicle opening common to both valves. In the dorsal valve there
is a high vertical plate to which are attached the descending branches ;
ascending branches not represented. Recent.

Ismenia, King. Coarsely plicate shells with the loop consisting of
fimbriate descending branches and simple ascending branches. Jura.

MwUfeldtia, Bayle (Megerlea, King), (Figs. 558, 559). Jura to Recent.

Frenulina, Dall. Sub-genus of Muehlfeldtia. Recent.

FIG. 560.

A, B, Kingena lima, Defr. Cretaceous; England. Lateral and frontal aspect of loop, enlarged (after
Davidson). C, Specimen from the Galeritenplaner of Salzgitter, 1/1- D, External surface, enlarged.
E, F, Kingena Friesensis, Sclmifer sp. Upper Jura ; Gruibingen, Wiirtemberg. 1/1- (c> Crura ; d, Dental
sockets ; e, Jugum ; /, I, Ascending and descending branches of loop ; j, Cardinal process ; r, Point of recurva-
ture of loop ; S, Median septum).

Terebratalia, Beecher. Shell when adult like Terebratella, but passing
through a quite different series of metamorphoses. Recent.

Dallina, Beecher. Elongate Terebrataliae with a small cardinal process
and a ventral median sinus. Tertiary to Recent.

Macandrevia, King. Elongate Terebrataliae with dental plates and no
cardinal process. Recent. A sub-genus of Eudesia, according to Dall.

Laqueus, Dall (Frenula, Dall). Like Terebratalia, but the loop has two

Fio. 561.

Lyra Neocomiensis, d'Orb. Lower
Cretaceous ; Morteau, Doubs. Natural
size.

FIG. 562.

A, Trigonoscmus elegant, Defr. White Chalk;
England. Interior of dorsal valve, enlarged (after
Davidson). B, T. Palissyi, Woodw. Upper Cretace-
ous ; Ciply, Belgium. Vi- (Drawn from nature.)

lateral processes connecting the ascending and descending branches. Recent.

Kingena, Davidson (Kingia, Schoenbach), (Fig. 560). Cretaceous ; Europe
and North America.

Lyra, Cumberland
Europe.

(Terebrirostra, d'Orbigny), (Fig. 561). Cretaceous;

332

MOLLUSCOIDEA— BRACHIOPODA

SUB-KINGDOM V

Trigonosemus, Koenig (Fissurirostra, Fissirostra, d'Orb. ; Delthyridea, King),
(Fig. 562). Cretaceous; Europe.

Microthyris, Deslongchamps (Ornithella, Deslong.), (Fig. 563). Jura.

Zeilleria, Bayle, seems to diifer only in
having a biplicate dorsal valve. Europe.
Aulacothyris, Douville" (Fig. 564).
Trias to Cretaceous ; Europe. Eudesia,

FIG. 503

Micrathyrls lagennlis, Schloth. sp. Corn-
biasli ; Rushden, England. J/l (after Davidson).

FIG. 564.

Aulacothyris resupinata, Sow. sp. Middle Lias; II-
inster, England (after Deslongchamps).

King (Orthotoma, Trigonella, Quenstedt ; FlaMlothyris, Deslong.) Jura ; Europe.

Fimbriothyris and Epicyrta, Deslong. Jura. Camerothyris, Bittner. Trias.
Cincta, Quenstedt. Jura. Antiptychina, Zittel. Jura. Plesiothyris, Douville.
Jura ; Europe.

? Hynniphoria, Suess ; 1 Cruratula, Bittner ; 1 Orthoidea, Friren.

Sub-Family D. MAGELLAXINAE. Beecher.
Terebratellidae with the loop composed of descending and ascending branches, passing

FIG. 565.

Mm/us pumilus, Sow. \Vhite
Chalk ; Mention, near Parts. A, B,
Shell, i/!. C, Vertical section.
D, Interior of dorsal valve.

FIG. 566.

Coenothyris vulgaris, Schloth. sp. Muschelkalk ; Wiirzbnrg.
A, Dorsal and anterior views,1/!. B, Loop enlarged and restored
from sections treated with acid (partly after Koschiusky).

in the higher genera through metamorphoses comparable to the adult structure of Bou-

ORDER IV

TELOTREMATA

333

The lower genera become

i, Mill/a*, Muyasella, Tcrebratetta, muf Magellania.

in/ lilt Iff or*' i-nl fit! HI/ fill' tr nit illil I

stages. Jura to Recent. Recent
genera restricted to austral seas.

£ouchardia, Davidson (/W///-
i'h i/iii'li us, King). Recent; South
Atlantic.

N«ijas, Sowerby (Fig. 565).
Cretaceous; Europe. J/tfy >•<//",
Dall. Recent. Coenothyris,
Douville" (Fig. 566). Trias.

Terebratella, d'Orbigny (Del-
fhi/ris, Menke ; Ismenia, King ;
WaltoMO, Davidson), (Fig. 567).
Jura to Recent.

Minjellania, Bayle (IVald-
heimia, King; Neothyris, Dou-
ville), (Fig. 568, also Figs.
497, 498). Jura to Recent.

JHtf/nch&rina, Oehlert. Cretaceous. Megerlina, Deslongchamps. Recent.
Kraussina, Davidson (Kraussia, Davidson). Recent. Mannia, Dewalque.
Miocene. 1 Rhynchora, Dalman. Cretaceous.

FIG. 568.

.M<><l<:U<tniafl(n-escens, Val. Recent ;
Australia. Interior of dorsal valve,
somewhat enlarged.

Superfamily 3. SPIRIFERACEA. Waagen.

Telotremata with the adult brachia supported by calcareous spiral lamellae or
spiralia. Ordovician to Jurassic.

The Spiriferacea are abundantly represented from the Silurian to the Carboniferous,
during which time the jugum undergoes many and often rapid changes. The brachidia
in Zygospira are known to begin with a Centronella-like loop, as in the primitive Tcre-
bratulaceck

Family 1. Atrypidae. Gill.

Spiriferacea with the crura directly continuous with the primary lamellae, which
diverge widely and have the spiral cones between ////•///.
Jugum simple, complete, or incomplete. Ordovician
to Devonian.

This family is divided into Zygospirinae,
and Atrypinae, according to modifications of the jugum
or position of the spirals.

Zygospira, Hall (Anazyga, Davidson ; OrtJunm-
maea, Hall ; Hallina, Winchell and Schuchert ;
Protozyga, Hall and Clarke (Fig. 569). Like
Atrypa, but small, and the spirals composed of
fewer coils. Jugum a simple connecting band,
situated rather anteriorly. Surface sharply
plicate, never lamellose. Ordovician and Sil-
urian ; North America.
Catazyga, Hall and Clarke. More rotund and finely striated than Zygospira.

FIG. 569.

Zygospira modest a, Hall. Ordovician
Cincinnati, Ohio. »/i (after Hall).

334

MOLLUSCOIDEA— BRACHIOPODA

SUB-KINGDOM V

with the complete jugum decidedly posterior in position. Ordovician arid
Silurian ; North America.

Atrypina, Hall and Clarke. Primitive Atrypae with few plications, and
but three or four volutions in each spiral. Jugum as in Atrypa, but continuous.

Silurian to Devonian ;
North America and
Europe.

Glassia, Davidson
(Fig. 570). Small smooth
shells, with the apices of
the laterally compressed
spirals situated at the
centre of the brachial
cavity. Jugum similar
to that of Atrypina. Or-
5/2 (after David- dovician to Devonian ;

Europe.

Dayia, Davidson (Fig. 571). Small smooth shells, with the jugum situated
anteriorly, and drawn out posteriorly into a simple short process. Spiralia
laterally directed. Silurian ; Europe.

Atrypa, Dalman (Cleiothyris, Phill. ; Spirigerina, d'Orb.), (Fig. 572). Shell
radially plicated, usually with lamellar expansions or hollow spines. Spirals
introverted, dorso-medially directed. Jugum extremely posterior in position,

FIG. 570.

Glassia obovata, Sow. sp.
Silurian ; Wenlock, England.
Interior of dorsal valve, 3/i
(after Davidson).

FIG. 571.

Dayia navicula, Sow. sp.
Ludlow, Shropshire,
son).

Silurian

FIG. 572.

Atrypa reticularis, Lin. sp. Middle Devonian; Gerolstein, Eifel. A, Dorsal aspect of adult specimen.
B, Ventral aspect and profile of young shell. C, Interior of dorsal valve, showing spiralia, crura, and jugum.
D, Ventral valve, showing muscular and vascular impressions («, Adductors ; c, Diductors ; d, Deltidial plates ;
o, Ovaries ; p, Pedicle muscle).

and complete in young stages ; but mesially absorbed at maturity. Widely
distributed in the Silurian and Devonian.

Gruenewaldtia, Tschernyschew. Atrtjpa-\ike> shells, but with the relative
convexity of the valves reversed. Devonian ; Eussia.

1 Karpinskya, Tschernyschew. Elongate, Atrypa-\ike shells, with a median
dorsal septum. Devonian ; Eussia.

1 Clintonella, Hall and Clarke. Silurian ; North America.

Family 2. Spiriferidae. King.

Spiriferacea with the crwa directly continuous with the bases of the primary
lamellae, which are situated between the laterally directed spiralia. Jugum simple,
complete, or incomplete. Silurian to Jurassic.

ORDER IV

TELOTREMATA

335

This family is divided into the following sub-families — Suessiinae, Uncitinae, and
Trigonotretinae.

Ci/rtina, Davidson (Fig. 573). Cyrtia-\ike shells, with the dental lamellae
converging and united with the median septum. Loop V-shaped, complete:
Silurian to Lower Carboniferous. Distribution general.

Thecocyrtella, Bittner. Very small, ventrally cemented, smooth -shelled
Ct/rflnae. Alpine Trias.

Eittnerula, Hall and Clarke. Like Thecocyrtella, but with the abbreviated

FIG. 5

A, Cyrtina heteroclyta, Defr. sp. Devonian ; Eitel. Vi- -B, Shell
with dorsal valve mostly removed, showing spiralia, «/a (after David-
son). C, Cyrtina carbonaria, M'Coy. Carboniferous Limestone;
Kendal, Ireland, 1/1- Interior of ventral valve. The pseudodeltidium
is removed to show the dental plates and median septum.

FIG. 574.

Spiriferina restrain, Sow.
Middle Lias ; Ilminster. 1/1
Davidson).

sp.
(after

dental plates uniting with the very high median septum, forming a transverse
platform beneath the united deltidial plates. Alpine Trias.

Spiriferina, d'Orb. (Fig. 574). Like Spirifer, but with the shell substance
punctate, and a prominent ventral median septum. Loop
simple, complete. Carboniferous to Jura.

Suessia, Deslongchamps. Similar to Spiriferina, but
the dental plates not extending to the bottom of the valve.
Jugum with a median process. Jura ; Europe.

Untiles, Def ranee (Fig. 575). Shells rostrate, striate,
with the ventral beak long, frequently distorted and
arched. No cardinal area. Deltidial plates united,
forming a concave plate. Pouch-like plates just within
the margins of the dorsal valve. Devonian ; Germany.

Uncinella, Waagen. Carboniferous ; India.

Spirifer, Sowerby
Fischer de Waldheim

FIG. 575.

(Trigonotreta, Koenig ; ChoristUes,

Brachythyris and Fusella, M'Coy; Uncites( ,hus schi

HysterolithuS, Quenstedt), (Fig. 576). Shell radially Devonian'''; Beuzberg, near

plicated or striated, crossed by concentric growth-lines, c
lamellae, simple, or compound spines. Hinge-line generally long and straight.
Ventral valve usually with moderately high cardinal area, and stout simple
teeth supported by short dental lamellae. Delthyrium open. Spirals directed
towards the cardinal angles of the valves. Jugum at maturity represented
by two short spur-like processes, which are not in contact with each other.
Generally distributed and extraordinarily abundant in the Silurian, Devonian,
and Carboniferous.

336

MOLLU SCOIDEA— BRAOHIOPODA

SUB-KINGDOM V

The species of Spirifer have recently been grouped by Hall and Clarke into six
sections as follows : — Radiati, with fine filiform striae ; Lamellosi, with concentric

A, Spirifer striatus, Sow. Carboniferous Limestone ; Ireland. Portion of dorsal valve removed, showing
spiralia, a/4 (after Davidson). B, S. speciosus, Schloth. sp. Devonian ; Eifel. 1/1- C, S. macropterus, Goldf. sp.
Devonian ; Coblenz. Cast, 1/1- D, S. Mosquensis, Vern. Sub-Carboniferous ; Moscow. E, Same, interior of
ventral valve, !/] (p, Pseudodeltidium ; x, Dental plates).

lamellae ( = Delthyris, Dalman) ; Fimbriati, with concentric rows of fine spines ( = Reti-
cularia, M' Coy) ; Aperturati, with plications on fold and sinus ; Ostiolati, with the
median fold and sinus without plications ; Glabrati, with the surface smooth and
glabrous ( = Martinia, M'Coy ; Martiniopsis, Waagen ; and Mentzelia, Quenstedt).

Cyrtia, Dalman (Fig. 577). Distinguished from Spirifer by having an
unusually high ventral area, with its delthyrium closed by a perforated
deltarium. Silurian to Devonian ; Europe and North
America.

Syringotkgris, "Winchell. Spirifer-like shells, usually
with large and erect cardinal areas and an internal tube
or syrinx, situated in the delthyrium. Carboniferous ;
North America and Europe.

Ambocoelia, Hall. Small, concave, or plano-convex,

saurian ; Gottiand. 'Natural usuauy smooth Spirifer-like shells. Four well-defined
adductor scars near the anterior margin in the dorsal
shell. Devonian tc Carboniferous ; North America and Europe.

Ferneuilia, Hall and Clarke. Small Spirifers, with a deep median sinus
and two pronounced divergent ridges on each valve. Devonian to Carboni-
ferous ; Europe.

FIG. 577.
Cyrtia exporrecta, Dalm.

OIIDKH IV

TELOTREMATA

337

Metaplasia, Hall and Clarke. Spirifer-\ike shells, with a median fold on
the ventral valve and a sinus on the dorsal valve. Lower Devonian ; North
America.

Family 3. Athyridae. Phillips.

Spiriferacea with tJie bases of the primary lamellae situated between the spiralia,
and sharply rer'urm/ i/<>r.wll>( nf fl/> //• jinn-lion with the crura. Spiralia more or less
laterally directed. Jugum complete, V-shaped, with the apex drawn out into a simj)le,
bifurcated, or otherwise modified pi'ocess. Silurian to Trias.

This large, chiefly Palaeozoic family, with its numerous highly differentiated species,
is divided into six sub-families, on the basis of the simplicity or complexity of the
juguni. These are the Rhynchospirinae, Hindellinae, Athyrinae, Diplospirinae, Koninck-
ininae, and Meristellinae.

h'lii/nchospira, Hall (Fig. 578, C, D). Rostrate, radially plicate shells with
a short curved hinge-line ; apex truncated by a circular pedicle opening.
Dorsal hinge-plate like that of Trematospira. Spirals with from six to nine
volutions. Jugum V-shaped, expanding apically and terminating posteriorly
in an oblique edge. Shell structure punctate. Devonian to Lower Carboni-
ferous ; North America and Europe.

Homoeospira, Hall and Clarke. Like the last, but differs in having a linear
cardinal 'process separ-
ating the crural plates.
Jugum not apically
expanded, but termi-
nating in an acute
stem. Silurian ; North
America.

Ptychospira, Hall
and Clarke (Fig. 578,
A, B). Like Rhyncho-
spira, but with a few
angular plications. The FIG. 578.

. c , r i . •, A, Jl, Ptychospira ferita, von Buch. Devonian; Gerolstein, Eifel. 1/1-

JUgUm naS a long Simple c, D, Rhynchospim Salteri, David. Silurian; Wenlock, Shropshire. C, In-

terior of dorsal valve.
(after Davidson).

D, Median vertical section through both valves,

nrnnocs ™»ecnrr rmf

'"

ward between the coils

to near the inner surface of the ventral valve. Devonian to Lower Carbon-

iferous ; North America and Germany:

Retzia, King (Trigeria, Bayle). Resembling Rhijnchospira externally. The
ventral umbonal cavity has a split tube. The single process of the Jugum
terminally forked. Devonian ; Europe.

This genus formerly contained all shells having a Retzioid exterior. At present,
however, but a single species is admitted.

Hustedia, Hall and Clarke. Externally like Eumetria, but with coarse
plications, and internally with a split tube, as in Retzia. Spirals and jugum
similar to that of Eumetria, but with fimbria and spinules respectively.
Upper Carboniferous ; America, Europe, India, and China.

Trematospira, Hall. Transverse Rhynchospirae. Silurian and Devonian ;
North America.

VOL. I Z

338

MOLLUSCOIDEA— BRACHIOPODA

SUB-KINGDOM V

FIG. 579.

Parazyga, Hall and Clarke (Fig. 579). Like Trematospira, but with the
fine, simple ribs covered with very delicate, shqrt, hair-like spines. De-
vonian ; North America.

Eumetria, Hall. Elongate terebratuliform shells with numerous fine
radiating striae. Hinge-line short. Dorsal hinge-plate very complicated.
Jugum similar to that of Metzia, but the terminally
bifurcated process is extended backward at an abrupt
angle, and terminates just in front of the apices of the
primary lamellae. Shell structure punctate. Lower
Carboniferous ; North America and Europe.

Acambona, White. Carboniferous ; North America.

Hindella, Davidson (1 WTiitfaldella, Hall and Clarke).
Ovate or elongate, sub-equally convex, smooth, Athyroid
shells. The V-shaped jugum has a short, acute process.
A dorsal median septum present. Silurian and De-
vonian ; North America.

Hyattella, H. and C. Similar to JHiitfieldella, but
compactly sub - pentahedral, and without the dorsal
median septum. Silurian ; North America.

parazygahirsuta,UM. De- Nudeospira, Hall (Fig. 580). Sub-circular, biconvex
tuck"1 '4 Siofthe natural sne^s w^tn numerous, fine, short spinules. Jugum with
size. 'B, 'same with dorsal a long, straight, simple process. Silurian to Lower
Carboniferous; North America and Europe.

Anoplotheca, Sandberger (Bifida, Davidson). Concavo-
convex small shells with few plications, crossed by fine,
often imbricating growth lines. Jugum originating near the mid-length of
the primary lamellae, uniting and forming a simple upright stem articulating
in a cavity in the ventral valve. Dorsal
valve with a high median septum. De-
vonian ; Germany and France.

Coelospira, Hall (Leptocoelia, Hall).
Shells externally much like Atrypa, but
with laterally directed spirals. Jugum
similar to that of Anoplotheca. Silurian
and Devonian; America, Europe, and
South Africa.

Anabia, Clarke. Similar to Coelo-
spira, but with a highly convex dorsal
valve. Silurian; Brazil,

Vitulina, Hall. Like Coelospira, but
with few plications and a long hinge -line. Plications covered with fine
radiating lines or rows of pustules. Devonian ; America and South Africa.

line of ventral valve, enlarged
(after Hall).

FIG. 580.

Nudeospira pisum, Sow. Silurian ; Wenlock, Eng-
land. A, Interior of dorsal valve. B, Vertical
section through both valves, 5/2 (after Davidson).

Biconvex, smooth-shelled
Silurian ; North America

Meristina (WTiitfieldia, Davidson), (Fig. 581).
Athyroids. Jugal stem with a short bifurcation,
and Europe.

Glassina, Hall and Clarke. Like Meristina, but with the bifurcations of
the jugum originating directly from its apex. Silurian ; England.

Athyris, M'Coy (Spirigera, d'Orbigny ; Euthyris, Quenstedt), (Fig. 582).

ORDER TV

TELOTREMATA

33!)

Sub- equally biconvex shells with concentric growth lines extended into
lamellae. Ventral urnbo not prominent, incurved, usually concealing the

FIG. 581.

)tna tumida, Dalm. sp. Silurian ; Gottland. --1, Shell of the natural size. B, Interior of ventral valve-
C, Hinge-line and median septum of dorsal valve.

pedicle opening and deltidial plates. Teeth supported by dental lamellae.
Hinge-plate of the dorsal valve perforated by a "visceral foramen." The

Fio. 582.

ntrica, von Buch sp. A, Shell with dorsal valve partly removed. B, Interior of dorsal valve,
1/1. C, D, Frontal and lateral aspect of spiralia (after Davidson).

Devonian and

con-

peculiar jugum of this genus is illustrated in Fig. 582, 6', D.
Carboniferous. Distribution general.

Actinoconchus, M'Coy. Athyroids with very wide radially striate
centric lamellae. Carboniferous ; Europe.

Cleiothyris, King. Athyroids with concentric rows of flat spinules. Car-
boniferous and Permian. Distribution general.

Seminula, M'Coy. Smooth-shelled Athy-
roids. Dorsal hinge-plate very prominent.
Carboniferous. Distribution general.

SpirigereUa,W8AgeiL Carboniferous ; South
America and India.

Amphitomella, Bittner. Smooth - shelled
Athyroids with a double cardinal process and
median septa in each valve. Alpine Trias.

Tetradinella, Bittner (Plicigera, Bittner), (Fig. 583). Athyroids with
four corresponding ribs on each valve. Alpine Trias.

Pentadinella, Bittner. Athyroids with five corresponding ribs on each
valve. Alpine Trias.

Anomadinella, Bittner. Athyroids with a number of angular alternating
ribs towards the anterior margins. Alpine Trias.

FIG. 583.

Ti'tr<'i-t;,i<U" triiinni'llo, Schlotll.

Muschelkalk ; Recoaro, Italy, i/l-

340

MOLLUSCOIDEA— BRACHIOPODA

SUB-KINGDOM V

Pomatospirella, Bittner. Small smooth shells having the contour of Dayia
or Cydospira. Alpine Trias.

Kayseria-, Davidson. Lenticular, plicated shells with a median plicated
sinus on both valves. Jugum with a ventral articulating process and the
bifurcations continued between the spiral ribbons to their outer ends.
Devonian ; Germany.

Diplospirella, Bittner. Athyroids with the jugal processes coextensive
with the principal spiral coils. Alpine Trias.

Pexidella, Bittner. Athyroids differing from Diplospirella in that the
jugum is much reduced and situated in the umbonal region. Valves much
thickened in the apical region. Alpine Trias.

Euractinella, Bittner. Diplospirelloids with short corresponding ribs.
Alpine Trias.

Anisadinella, Bittner. Diplospirelloids with alternating ribs. The
secondary spiral coils give off a process which returns and joins the jugum.
Alpine Trias.

Koninckina, Suess (Fig. 584). , Shell sub-orbicular, concavo-convex, smooth,
with a straight hinge-line, or Strophomenoid in external appearance. Car-

FIG. 584.

Koninckina. Leonhardi, Wissin. sp.
Upper Trias ; St. Cassian, Tyrol. A, Shell
showing spiralia, enlarged. B, Ventral
and dorsal aspects, 1/1-

FIG. 585.

Amphiclina, with re-
stored brachidia (after
Bittner).

FIG. 586.

TJiecospira Haidingeri, Suess sp.
Rhaetic ; Starhemberg, Austria.
A, Ventral valve, 1%. B, C,
Brachidia, enlarged (after Zug-
meyer).

dinal area obsolete at maturity. The accessory spirals take their origin
from the upper surface of the jugum, and are coextensive with the primary
spirals. Trias ; Europe.

Amphiclina, Laube (Fig. 585). Like Koninckina, but sub-trigonal in out-
line, and with well-developed cardinal area and deltidial plates. Trias and
Jura ; Europe.

Koninckella, Munier-Chalmas. Similar to Amphiclina, but with well-
developed cardinal process. Trias and Jura ; Europe.

Amphidinodonta, Bittner. Like Amphiclina, but with interlocking denti-
culate ridges and tubercles within the margins of the valves. Alpine Trias.

Koninckodonta, Bittner. Like Koninckina, but with prominent cardinal
areas and a row of sub-marginal thickened tubercles on the interior of the
ventral valve, which interlock with similar callosities on the dorsal valve.
Alpine Trias.

Thecospira, Zugmayer (Fig. 586). Ventrally cemented Koninckinae with
well-developed cardinal area and cardinal process. Alpine Trias.

ORDER IV

TELOTREMATA

341

, Hall. Externally like Meristn, but. without spondylia. Ap«-x
of jugum with two annular processes. Devonian ; North an«l South America
ami Europe.

Charionella, Billings. Similar to the last, but with a greatly modified
hinge-plate. Devonian ; North America.

Pentagonia, Cozzens (Goniocoelia, Hall). Meristettae with a l»r<> nl, angular,
sharply limited, ventral sinus and abrupt lateral slopes. Dorsal valve with

FIG. 587.

Mi-ritta herculea, Barr. sp. Devonian (F-); Konieprus, Bohemia. A, External aspect of ventral valve,
broken away near the apex so as to show the "shoe-lifter process," 1/1- •#, Fractured shell showing median
septum ; spiralia destroyed (after Barrande). C, D, Frontal and lateral views of spiralia, slightly enlarged
(after Davidson).

a wide, rounded fold, divided by a narrow sinus and umbo-laterally with two
short flanges. Devonian ; North America.

Merista, Suess (Camarium, Hall), (Fig. 587). Like Meristella, but with a
spondylium. Silurian and Devonian ; Europe and North America.

Dicamara, Hall and Clarke. Meristellae with a spondylium (" shoe-lifter
process ") and brachidium. Europe.

Dioristella, Bittner. Similar to Meristella. Alpine Trias.

Camarospira, Hall and Clarke. Like Meristella, but with a small spon-
dylium supported by a median septum, to which is attached only the pedicle
muscle. Devonian ; North America.

Range and Distribution of the Brachiopoda.

Owing to their great abundance, world-wide distribution, and remote
antiquity, as well as their excellent state of preservation, Brachiopods
occupy a very conspicuous rank among extinct Invertebrates, and furnish us
besides with a large number of important index fossils. The calcareous com-
position of their shells enables them to resist the destructive action of the
fossilisation process more successfully than the shells of Mollusks, which are
composed for the most part of aragonite. Their value as index fossils,
however, is somewhat detracted from owing to the difficulty of identi-
fying numerous genera, without a knowledge of their internal structure.

The four orders into which the class is now divided are represented in
the lowest Cambrian, or Olenellus zone, indicating that Brachiopods had
their origin in Pre-Cambrian times. In the Lower and Middle Cambrian,
the Atremata and Neotremata predominate ; and although the Protremata are
known in the Lower Cambrian by very typical species, it is not until the
Upper Cambrian that the order becomes conspicuous. The Telotremata are

342

MOLLUSCOIDEA— BRACHIOPODA

BUB-KINGDOM V

TABLE SHOWING THE VERTICAL RANGE or* BRACHIOPODS.

—————— — — — _ — . ——I

— «•—

---------

^M^MHH

H^H^Ml

— — —--

§

— _— -_^-—--

•»---_-_-i

•^^^^

•---M--.

Q

1

05

S3

c3

S3

.

5

B

Families.

1

;§

c

.3

"3

rt

0

&*

^1

• ,3
1

o

1

O

.s

35

1

1

1

1

S
c

1-3

I

I

1

Order 1. Atremata

OBOLACEA

1. Paterinidae

_____

2. Obolidae

_______

____

3. Trimerellidae

_______

______

____

( LlNGULACEA

1. Lingulellidae

____

^__

2. Lingulidae

3. Lingulasmatidae

Order 2. Neotremata

ACROTRETACEA

1. Acrotretidae

2. Sipbonotretidae

_

___

DlSCINACEA

1. Treraatidae

________

— _ — _,

— ^ __.

2. Discinidae

^^ _ _

____

___

— «.

___

_____

____

.___,

___

____

CRANIACEA

1. Craniidae

_____

___-i

_____

_____

______

____

____

Order 3. Protremata

STROPHOMENACEA

1. Kutorginidae

____,

2. Eichwaldiidae

_____

3. Billingsellidae

________ ____

4. Strophomenidae

5. Tbecidiidae

_____

6. Productidae

_____

____

_^_^_-

_____

7. Richtbofenidae

8. Ortbidae

_____

____

—— —-

_____

PENTAMERACEA

1. Clitambonitidae

_____

____

___

2. Syntropbiidae

_______

3. Porambonitidae

_____

__ _ _

___

4. Pentameridae

--------

Order 4. Telotremata

RHYNCHONELLACEA

1. Protorhynchidae

_______

___

2. Rhynchonellidae

____

_ _ _ _.

_ _ _ _

________

____

— -—

____

___

___

____

TEREBRATULACEA

1. Centronellidae

____

2. Terebratulidae

-——

____

_____

3. Terebratellidae

_______

_____

SPIRIFERACEA

1. Atrypidae

___

____

____

__

2. Spiriferidae

____

_______

_____

_________

____

3. Athyridae

DISTRIBUTION 343

scarce throughout the Cambrian, but in the Ordovician, species and indi-
viduals abound.

In the Lower Cambrian (Olenellus beds); thirteen genera of Brachiopods
are represented, occurring both in North America and in Europe. A market!
increase is apparent toward the close of the Cambrian, and in the Ordo-
vician and Silurian, where the climax of their diversity is reached, upwards
of 2600 species are known. These are distributed chiefly in North America
and in Europe (Great Britain, Scandinavia, Bohemia, Russia, and Portugal) ;
but numerous forms are also found in South America, Australia, China, and
Eastern Siberia.

In the Devonian Brachiopods are scarcely less plentiful than in the
Silurian, although a considerable number of genera, especially those belong-
ing to the Atremata and Neotremata, have now disappeared. The most noted
European localities where Brachiopods abound are the Eifel, Rhineland, West-
phalia, the Hartz, Belgium, Devonshire, Boulogne sur Mer, Cabrieres in the
Cevennes, the Asturias, and the Ural. Canada and the Middle Western
States of North America also yield great quantities of Brachiopods.

The Carboniferous of North America and its equivalent horizons in
Europe and Eastern Asia, together with the so-called Permo-Carboniferous
of the Salt Range of India and Armenia, are very rich in Brachiopod remains,
especially those belonging to the Productidae, Strophomenidae, Spiriferidae, and
Rhynclwnellidae.

In the European Permian, the number of species of Brachiopods is reduced
to about thirty, but in the Salt Range of India greater numbers occur. In
the Alpine Trias, the Terebratulidae, fihynchonellidae, and Koninckinidae attain
an enormous development.

The Jurassic and Cretaceous Brachiopods belong almost exclusively to the
Terebratulidae, Rhynchonellidae, and the Thecidiidae ; the first two families in
particular being represented by an astonishing number of species. The
Spiriferacea become extinct in the Lias.

With the beginning of the Cenozoic era, Brachiopods are no longer a con-
spicuous group of fossils. The species occurring in the Tertiary are almost
without exception generically identical with those now living, and scarcely
exceed them in number. On this account they are devoid of practical
interest or importance to the geologist.

[The credit for having revised and practically rewritten the translation of the entire
Brachiopod chapter belongs to Mr. Charles Schuchert, of the United States National Museum.
The classification adopted has been taken from his Syno2)sis of American Fossil Brachiopoda,
now in press. — TRANS.]

Sub-Kingdom VI. MOLLUSCA.1

(Malacozoa, Blainville; Saccata, Hyatt.)

THE Mollusca form a well - characterised, and, on the whole, remarkably
homogeneous group of Invertebrates, which have existed since the earliest
recognised advent of life upon the globe. Their progressive modifications
afford us a most important guide to the successive stages of the evolution of
organic life as preserved in the various geological horizons.

The Mollusca are characterised as a group by passing through a Trocho-
sphere and a Veliger larval stage ; by possessing bilaterally symmetrical,
unsegmerited bodies ; a larval shell gland, from which a harder exoskeleton
or shell is secreted, though not always permanently retained ; a mouth,

1 Literature :

Adams, H. and A., The Genera of Recent Mollusca, 2 vols. London, 1853-58.
Philippi, R. A., Handbuch der Conchyliologie. Halle, 1853.

Keferstein, W., Die Malacozoa (Bronn's Classen und Ordnungen des Thierreichs, Bd. III.), 1862-66.
Tryon, G. W., and Pilsbry, H. A., Manual of Conchology, 16 vols. Philadelphia, 1879-96.
Fischer, P., Manuel de Conchyliologie et de Paleontologie conchyliologique, 1880-87.
Woodward, S. P., Manual of the Mollusca. 4th Edition, with Appendix by R. Tate, 1880.
Tryon, G. W., Structural and Systematic Conchology, 3 vols. Philadelphia, 1882-84.
Lankester, E. R., Encyclopaedia Britannica, Article Mollusca, 1883

Ihering, H, von, Le systeme naturel des Mollusques (Bull. Sci. de la France, XXIII.), 1891.
Pelseneer, P., Introduction a 1'etude des Mollusques. Brussels, 1894.

Soiverby, J., Mineral Conchology of Great Britain, 7 vols. London, 1812-30.

Brocchi, G. B., Conchiologia fossile subappenina, 2 vols. Milan, 1814.

Deshayes, G. P., Coquilles fossiles des environs de Paris, 3 vols., 1824-37.

Goldfuss, A., Petrefacta Germaniae, 1826-40.

Conrad, T. A., Fossil Shells of the Tertiary Formations of North America (1832-33) ; and Fossils

of the Medial Tertiary of the United States (1838-61). Reprints 1893.

Morton, S. G., Synopsis of the Organic Remains of the Cretaceous Group of the United States, 1834.
Philippi, R. A., Enumeratio Molluscorum Siciliae, 2 vols., 1836-44.
Grateloup, J. P. S., Catalogue zoologique du Bassin de Gironde. Bordeaux, 1838-40.
Hall, J., Palaeontology of New York, vols. I.-VIII. Albany, 1847-95.
Wood, S., Monograph of the Crag Mollusca (Palaeont. Soc. vols. I.-IL), 1848-56.
Sandberger, G. and F., Die Versteinerungen des Rheinischen Schichtensystems in Nassau, 1850-56.
Morris and Lycett, Monograph of the Mollusca of the Great Oolite (Palaeont. Soc.), 1850-63.
M'Coy, F., British Palaeozoic Fossils. London, 1851-55.
Pictet and Campiche, Description des Fossiles du terrain cretace de Ste. Croix (Palaeont. Suisse, ser.

V., vols. I.-IV.), 1858-71.
Quenstedt, F. A., Der Jura. Tubingen, 1858.

Sandberger, F., Die Conch ylicn des Mainzer Beckens. Wiesbaden, 1860-63.
Deshayes, G, P., Description des animaux sans vertebres decouverts dans le Bassin de Paris, 5 vols.

Paris, 1860-66.
Loriol, P. de, Monographs of the Fauna of the Upper Jura of Switzerland, Haute- Marne, Youne,

Boiilogne-sur-Mer, Valfin, Tonnerre ; of the Neocomian of Mt. Saleve ; the Urgouian of

Landeron ; the Gault of Cosne, etc., 1861-75.

BUB-KINGDOM vi MOLLUSCA 345

intestinal canal, ;iml anus; a closed, Imt partly lacunary circulation, assisted
by a heart with one or more auricles, and containing a usually colourless
body fluid or haemolymph ; a nervous system with at least three pairs of
--.-uiglia connected by commissures; sexual reproduction by eggs and sper-
matozoa ; audition and equilibration provided for by otocysts ; respiration
by ctenidial or secondary gills, or by the tegumentary surface, which may be
invaginated to form a pulmonary sac ; locomotion by a muscular organ called
the foot, or by special parapodial structures ; the organs normally paired,
and protected by a sac-like integument called the mantle ; and the visceral
sac having a tendency toward torsion, so as to become usually asymmetrical.
Sexually Mollusks are* usually dioecious ; or, if monoecious, incapable of self-
fertilisation.

Owing to the homogeneity of the group, its division into classes has been
attended with some differences of opinion, depending upon the point of view,
the anatomist laying more stress upon certain groups of characters, and the
morphologist upon others. From a general standpoint, the Mollusca are
readily divisible into four classes, as follows : — Pelecypods, Scaphopods,
Gastropods, and Cephalopods. The first of these is well marked off from the
rest by the absence of a distinct head and of a radula, and the two groups
have been contrasted as Glossophora (or Cephalophora) and Aglossa (or Lipo-
cephala). Eecent researches tend to show that the Pelecypoda form a degenerate
group, more nearly related to the Protogastropod than is the latter to the
Protocephalopod ; and that in any general arrangement, the Cephalopods are
rather to be contrasted with the three other groups combined.

M'Coy, P., Synopsis of the Characters of the Carboniferous Limestone Fossils of Ireland. London,

1862.

(>'»'>b, W. M., Palaeontology of California, vols. I., 1864, and II., 1869.
(;<•;,! if z, H. B., Die Dyas. Leipzic, 1864.
X''</nenza, G., Paleontologica Malacologica dei Terreni terziarii del Distretto di Messina (Mem. Soc.

Ital. Sci. Nat., vols. I.-IL), 1865-67.

Laube, G., Die Fauna von St. Cassian (Denkschr. Wiener Akad., Bd. XXV.), 1866.
\\'»,'then, A. H., Palaeontology of Illinois, vols. I.-VII. Springfield, 111., 1866-83.

IHoernes, M., Die fossilen Mollusketi des Tertiarbeckens von Wien (Abhandl. k. h. geol. Reichsanstnlt.
Bd. IV.), 1870.
Stoliczka, F., Cretaceous Fauna of Southern India (Mem. Geol. Survey of East India, vol. II.,
Gastropoda, and III., Pelecypoda), 1868-71.
n>-li<tf,U-t L., and Sacco, F., I Molluschi terziari del Piemonte e delle Liguria, 1872-96.
tjlabb, W. M., Topography and Geology of Santo Domingo (Trans. Am. Phil. Soc., XV.), 1873.
&i,«lberger, F., Die Land- uud Siisswasser Conchylien der Vorwelt. Wiesbaden, 1875.
Meek, F. B., Report on the Invertebrate, Cretaceous, and Tertiary Fossils of the Upper Missouri
Country (U.S. Geol. Surv. Terr., vol. IX.), 1876.
Fontannes, F., Les Mollusques pliocenes de la Vallee de Rhone et du Roussillon, 1879-83.
jSeguenza, G., Le formazioni terziarie nella provincia di Reggio, Calabria (R. Acad. dei Lincei), 1880.
Waagen, W., The Salt Range Fossils (Mnn. Geol. Surv. India; Palaeont. Indica, ser. XIII.),

1880-87.
White, C. A., Review of the non-marine fossil Mollusca of North America (Kept. U.S. Geol. Survey),

1883.

ll-1-stpfd, J., Mollusken der Aachener Kreide (Palaeontographica, Bd. XXXIV.), 1887.
Ci-ossma/in, M., Catalogue illustro des coquilles fossiles de 1'Eocene des environs de Paris (Ann.

Soc. Malac. Belg., vols. XXIII.-XXVIII.), 1888-94.
Koenen, A. von, Das norddeutsche Unter-oligocan und seine Molluskenfauna (Abh. zur geol.

Special-Karte von Preussen, Bd. X.), 1889-93.
Dally W. H., Contributions to the Tertiary Fauna of Florida, I.-III. (Trans. Wagner Inst. Science,

vol. III.), 1890-95.
Walcott, C. D., Fauna of the Lower Cambrian or Olenellus Zone (10th Ann. Rept. U.S. Geol. Surv.),

1890.
Crossmann, M., Essais de Paleoconchologie comparee. Paris, 1895.

346 MOLLUSCA SUB-KINGDOM vi

Class I. PELEOYPODA. Goldfuss.1

(Lamellibranchiata, Blainville ; Conchifera, Lamarck ; Bivalvia (Bonanni), Linne ;
Lipocephala, Lankester.)

Aquatic, bilaterally symmetrical, acephalous mollusks, protected by a pair of
valves, which are secreted by the lateral portions of the mantle, connected by
a ligament, and moved by the contraction of muscles attached to the inner faces of
the valves ; feeding by ciliary action and destitute of a radula or jaw ; breathing by
lateral gills ; imperfectly sensible to light and rarely provided with peripheral visual
organs ; possessing olfactory organs (osphradia), auditory and equilibrating organs
(otocysts), tactile papillae, and a nervous system composed of ganglia united by
nerves, but without a pedovisceral commissure ; provided with an extensile, tactile, or
locomotor organ (foot) ; a circulatory system containing haemolymph, and operated
by a single or paired cardial ventricle and two auricles ; a more or less convoluted
intestinal canal, with its oral and anal extremities at opposite ends of the body ; a
stomach; paired nephridia, connected with the pericardium, and discharging in-
dependently of the rectum ; reproducing without copulation, by eggs and spermatozoa ;
monoecious or dioecious; development external to the ovary ; the post-larval stage
pi'otected by a prodissoconch, and sometimes exhibiting a special nepionic stage.

External Characters. The Shell. — The embryonic Pelecypod is pro-
vided with a saddle-shaped, single shell gland, which secretes a pellicle of the
same form, upon which, at two points corresponding to the valves, calcification
sets in independently. These rudiments remain connected across the dorsum

1 Literature (see also, under the head of Mollusca, pp. 344-345) : •

Wood, AS'., Monograph of the Eocene Bivalves of England (Palaeont. Soc.), 1861.
Zittel, K. A. von, Die Bivalven der Gosaugebilde (Denkschr. der Wiener Akad., XXV.), 1865-66.
Coquand, H., Monographic du genre Ostrea des terrains cretaces, 1869.
Barmnde, J., Systeme Silurien de la Boheme (Acephales, vols. I.-IV.), 1882.

Bohm, G., Die Bivalven der Stramberger Schichten (Palaeont. Mittheil. Mus. Bay. Staates, II.), 1883.
Neumayr, M., Znr Morphologic des Bivalveuschlosses (Sitzungsber. Wiener Akad. Bd. LXXXIIL),

1883.— Ueber die Herkunft der Unioniden (id., Bd. XCVIIL), 1889.
White, G. A., Review of the fossil Ostreidae of North America (Ann. Report U.S. Geol. Survey, for

1883), 1884.

Hall, J., Geological Survey of New York, Palaeontology, vol. V., 1884-85.
de Koninck, L. G., Fauna du Calcaire carbonifere de la Belgique (Ann. du Mus. d'hist. nat. de

Belgique, vol. V., pt. 5), 1886.
DaU, W. H., On the Hinge of the Pelecypods and its development, etc. (Am. Journ. Sci. [3], vol.

XXXVIII.), 1889.
Jackson, R. T., Phylogeny of the Pelecypoda. The Aviculidae and their Allies (Mem. Boston. Soc.

Nat. Hist, vol. IV., No. 8), 1890.

Menegaux, A., Recherches sur la circulation des Lamellibranches marines, 1890.
Neumayr, M., Beitrage zu einer morphologischen Eintheiluog der Bivalven ; mit Vonvort von E.

Suess. (Denkschr. Wiener Akad., Bd. LVIIL), 1891.

Hyatt, A., Remarks on the Piunidae (Proc. Boston Soc. Nat. Hist., XXV.), 1892.
Moynier de Villepoix, R., Recherches sur la formation et 1'accroissement de la Coquille des

Mollusques. Thesis, 1893.
Ulrich, E. 0., New and little known Lamellibranchiata from the Lower Silurian Rocks of Ohio, etc.

(Rept. Geol. Surv. Ohio, vol. VII.), 1893.— New and little known Lamellibranchiata of

Minnesota (Rept. Geol. Surv. Minn., vol. III.), 1894.

Bernard, F., Premiere note sur le developpement et la morphologic de la coquille chez les Lamelli-
branches (Bull. Soc. Geol. de France [3], vol. XXIII.), 1895.
DaU, W. H., A new Classification of the Pelecypoda (Trans. Wagner lust. Sci. Philadelphia, vol.

III., pt. 3), 1895. Also Proc. U.S. Nat. Mus., vol. XVII., No. 1032, 1895.
Hyatt, A., Terminology proposed for the Description of the Shell in Pelecypoda (Proc. Am. Assoc.

Adv. Sci. vol. XLIV.), 1895.

PELECYPODA

347

OLAflB I

for a time, by the uncalcified portion of the original pellicle, which develops

into the ligament of the adult. The paired embryonic shell, corresponding to

the protoconch of Cephalopods, has been named by

Jackson the prodissoconch (Figs. 588, 589). In

general these valves are very uniform in character,

as seen on the tips of the uneroded valves in the

adult. They are usually rounded or slightly pointed

at the umbonal end, and have in their earliest stages

a straight, rather long hinge line. In Solemya the

prodissoconch is elongate, rounded at the ends, with

the ventral and dorsal margins nearly parallel, much

as in the adult shell. In Pinna the prodissoconch

is globular, as in most bivalves. In Unto, Anodon,

and Philobrya, a second or nepionic stage is traceable,

owing to a semi-parasitic habit of the young, which leave the mother and

become encysted on the fins or gills of fishes ; during this period the shell

Fio. 5S8.

tli«' anti-rifir finl (-I). and from th>-
ri-ht tipi.'-r .si. I.- (/;). ":/, (after
Jackson).

FIG. 589.

A, Avicula sterna. Young specimen, viewed from the left (a) and right (1>) sides, the latter showing byssal
sinus. U/i. B> Area pexata. Very young, showing prodissoconch (p), succeeded by early dissoconch growth.
*Vi (after Jackson).

remains stationary, though some development of the contained soft parts is in
progress.

The bivalve shell reduced to its lowest terms comprises two convex pieces
(the valves), attached to one another dorsally (1) by an elastic ligament
external to the cavity of the two valves ; and (2) by muscles and connective
tissues which pass from the inner surface of one valve to the inner surface of
the opposite valve. The contraction of the muscles brings the margins of the
valves into close contact, thereby forming a hollow receptacle in which the
soft parts of the animal are enclosed, and from which all obnoxious foreign
matters may be excluded. The elasticity of the ligament, acting on the
principle of the C spring, tends to separate the valves when the tension of
the internal adductor muscles is relaxed. The substance of the valve is
secreted by marginal glands around the edge of the investing tissue or mantle,
and is subsequently reinforced by material supplied by secretion from the
general surface of the mantle. As the animal grows and the original pro-
dissoconch becomes too small to cover the soft parts, the valves are enlarged
around the margins, so that each of them represents, fundamentally, a hollow
cone. Since growth progresses more rapidly along some portions of the
mantle than at others, the cones necessarily become oblique, arched, or
cycloidally curved. The apex of the cone is formed by the beak or umlo of
the shell, the base is the entire margin of the valve.

The shell of most Pelecypods is composed of several layers of distinct

348

MOLLUSCA

SUB-KINGDOM VI

FIG. 590.

Vertical section of the shell of Unio. e, b, a, a', the outer prismatic
layer, showing successive increments of shell growth ; c, c', the inner
lamellar strata. Highly magnified (after Carpenter).

structure. The external layer is usually thin, .flexible, and dark-coloured,
chiefly composed of a horny substance termed conchiolin. This layer is
known as the epidermis, or more properly the periostracum ; it is not easily
corroded, and hence serves as a protection to the underlying calcareous
layers. The outer calcareous layer is composed of prisms of calcite arranged
more or less perpendicular to the external surface ; the inner layer is made
up of thin, more or less parallel lamellae of porcellanous or pearly texture,
disposed at right angles to the general direction of the prismatic layer,

and exhibiting the minera-
logical characters of ara-
gonite (Fig. 590). Besides
the lamellar or prismatic
structure, many forms
show under the micro-
scope minute, sometimes
branched tubulation.

The variations in shell

Substance are SOine what
pharapfpristif of fliflfprpnt

groups. I he prisms vary
greatly in size, the larger occurring in Inoceramus and Pinna, the smaller
in the Anatinidae and Myacidae. The prismatic layer is wholly absent in
the Chamiclae and many other Teleodesmacea ; in the Pectinidae and Limidae
the prismatic layer is feebly developed and often recognisable only in young
shells. In the Rudistae the prisms run nearly parallel with the outer surface.
As aragonite is more soluble than calcite, it frequently happens in fossil
shells that the layers composed of the former mineral have entirely dis-
appeared, leaving only the calcitic layers. Pearls are merely loose portions
of the inner layer secreted by the mantle surface, usually around foreign
bodies which have reached the interior of the shell and set up irritation there.

In the majority of Pelecypods the valves form a nearly complete defence ;
in borers, burrowers, and a few degenerate types, the valves cover less and
less surface in proportion to that which is bare ; in a few the mantle is re-
flected so as to envelop more or less of the outer surface of the valves ; and
finally, in Chlamydoconcha, the valves are permanently internal, separately
encysted, with the ligament isolated and encysted between them. No
example is known of a Pelecypod absolutely destitute of valves in the adult
state.

The valves of the shell are in general substantially equal ; but sometimes
they are unequal, especially in sessile or sedentary forms ; and rarely they
are spirally twisted, as in Stavelia and Spirodomus. The hinge or articuhis
comprises the whole articulating apparatus, — hinge plate, teeth, ligament, etc. ;
the primitive hinge, which is coextensive with the ligament, is distinguished
by Hyatt as the cardo. The cardinal axis, or right line forming the axis of
revolution of the hinge, is parallel with the antero-posterior axis of the
animal (as determined by a line drawn through the mouth and posterior
adductor) in the ordinary Teleodesmacea; but in the winged Prionodesmacea,
such as Ostrea, Perna, etc., the two axes are at a considerable angle with each
other.

The dental armature is usually situated on the dorsal margin, which for

CLASS i PELECYPODA :n-.»

this reason is called the cardinal margin. It comprises the teeth, or project-
ing processes and sockets, usually alternating in the single valve, and oppo.-itr
with respect to both valves. In the more modern and perfected types, the
cardinal margin is reinforced by a vertical deposit of shell in the form of a
lamina called the hin<j<- /'luff, upon which the teeth are set. Above the hin^i-
plate in each valve rise the beaks or umbones, which are usually curved
toward the anterior end of the shell (prosogyrate), but are sometimes directed
backward (opisthogyrate) or outward (spirogyrate).

According to the ordinary terminology, the height of a Pelecypod is
measured on a vertical from the beaks to the ventral margin ; the \< /»<////
corresponds to the greatest distance between the margins parallel with the
antero-posterior axis above defined ; and the thickness, or diameter, is measured
by a line at right angles to the vertical plane descending from the cardinal
axis (Fig. 592). When the shell is placed with the oral end anterior, the
valves are termed right and left respectively, as viewed from above the
articulus. The portion of the shell anterior to the beaks is usually shorter
than that behind them, except in such forms as Donax or Nucula.

Viewed laterally, most Pelecypod valves may be divided into regions,
corresponding in the main to the disposition of the internal organs. The oral
area extends from the anterior end of the cardinal line to the anterior side of
the pedal area. The latter is often marked by a swelling of the valves, and
sometimes by a sinus (Pholas) • it extends backward to a point where the
branchial crest, radiating from the beaks, forms the anterior boundary of the
siphonal area. The dorsal or posterior limit of the siphonal area is marked bv
an angle in the incremental lines ; and above this, extending to the posterior
end of the cardinal line, is the intestinal area. In the alate forms, like Ptcria,
the wings usually called anterior and posterior are really, with reference to
the antero-posterior axis of the animal, dorsal and ventral.

In certain borers, the siphons are greatly produced outside the valves, and
a calcareous tube is secreted, lining the burrow ; the valves, situated at the
anterior end of the boring, either lie free, or are partially or wholly fused
with the tube. In the Plwladidae the naked portions of the animal between
the edges of the valves are often protected by additional shelly pieces, which
are organically separate from the valves ; and some burrowers have the free
ends of the siphons protected by leathery or calcareous shields. In the
Teredinidae these shields are specially modified to protect the entrance of the
burrow, and are called " pallets."

Ornamentation. — The external ornamentation of the valves is always a
conspicuous character. It comprises (beside the concentric or incremental
lines which indicate the successive additions to the shell margin, and are
believed to coincide with resting stages during the process of growth) radial
or concentric striae, ridges, ribs, folds, nodes, spines, or foliaceous processes.
These are supposed to arise from temporary or permanent modifications of
the mantle margins, such as papillae, minute tentacular, or proliferate pro-
cesses. Other modes of ornamentation, such as that observed on the beaks
of Unionidae, proceed from the serrate margin of the glochidial shell.

Above the hinge line, in archaic types, is an area often set off by an
impressed line and called the cardinal area. In the more perfected modern
forms this area is commonly divided ; a heart-shaped space in front of the
beaks, and bounded by a ridge or groove, being known as the lunule ; and a

350 MOLLUSCA SUB-KINGDOM vi

more elongated space extending backward from the beaks being designated the
escutcheon. Both areas often have a special sculpture, differing from that of
the remainder of the shell.

Another form of ornamentation is sometimes found on the opposed inner
margins of the valves, away from the hinge line, as in JVoodia (Fig. 707),
or Transenella ; it probably aids in preventing a lateral displacement of the
valves. In general, all ornamentation may be confidently ascribed to a
dynamic origin.

Internal Characters. Soft Parts. — The Pelecypod body is enclosed
within two thin, partly fleshy mantle lobes, which are united or continuous
below the cardinal margin, and open or partially united at other points on
their periphery. Within the mantle lobes are the visceral mass including
the internal organs, the gills or ctenidia, the foot, and the palpi. When the
mantle edges are united so as to form tubes for the entrance and discharge of
water, such tubes are called siphons. These organs, all of which have been
utilised in classification, will be considered separately.

The mantle is closely applied to the surface of the valves, and is usually
attached to them along a line near its periphery. This line is indicated by a
continuous scar or impression upon the inner surface of the valves, termed
the pallial line. Outside the pallial line a portion of the margin is free and
usually thickened. In it are contained the glands which secrete the shell, .
and also pigment glands ; it is ornamented by papillae, tentacular processes,
etc., and is sometimes furnished with visual organs of a primitive sort.
Certain archaic forms had no distinct pallial line, the mantle being organi-
cally attached over a more or less irregular area. The ends of the pallial
line are commonly continuous with the scars of the adductor muscles.

The majority of Pelecypods have two adductor muscles, and are distinguished
accordingly as Dimyarian, or Homomyarian ; in some the anterior muscle is
absent or degenerate (Monomyaria) ; and in others an intermediate condition
obtains (Heteromyaria or Anisomyaria). The number and position of the
adductors was formerly accepted as a fundamental feature in classification,
although many difficulties were presented by exceptional cases. Eecent re-
searches have shown that an absolute foundation for classification cannot be
afforded by the number of adductors; but still, if allowance be made for
degeneration caused by inequilaterality, torsion, and other causes, the general
myarian types harmonise fairly well with the larger divisions based on the
totality of characters.

The visceral mass, as a rule, occupies the upper portion of the shell, and
contains the heart, intestinal canal, generative organs, renal and other
glands. The rectum usually lies above the posterior adductor, and dis-
charges into the anal siphon, when present. The mouth is placed at the
forward end of the visceral mass below the anterior adductor, and is commonly
furnished on each side with a pair of leaf-like expansions of the integument
called palpi, which are ciliate internally, and serve to conduct alimentary
matter from the gills to the mouth. Palpi are seldom wanting, and their
form and character remains fairly constant throughout a number of groups.
The mouth itself is unarmed, and the alimentary canal is more or less bent,
usually exhibiting a dilation which is regarded as the stomach.

The Foot. — From the ventral surface of the visceral mass projects an
extensile muscular organ, known as the foot, which is capable of being pro-

CLASS l PELECYPODA 3ft]

truded beyond the margins of the valves, or entirely retracted within the
mantle lobes. The muscles serving to move this organ are inserted upon the
shell near the adductor scars, leaving small accessory impressions. In a
large majority of bivalves, the foot has the familiar hatchet-shape from which
the class name is derived, but as an organ of locomotion, tactile use, and
possibly prehension, it is modified for special uses in many forms. A few
mollusks, such as Ostrea, have the foot altogether aborted, though remnants
of its retractor muscles exist and are attached to the valves ; and in some
cases (Pholadomya, Halicardia) an accessory foot-like organ, or " opisthopodium,"
is developed at the posterior end of the visceral mass.

In many Pelecypods the foot is provided with a gland secreting horny
matter which solidifies in threads after extrusion, forming a fixative tuft or
cable called the byssus, by which the animal adheres to extraneous objects.
Some sessile genera have the byssus more or less calcified, when it forms a
shelly plug closing a sinus or foramen in one of the valves through which it
passes. Many of the Pectinidae have a comb-like series of denticles (ctenolium)
on the edge of the byssal sinus, in which the byssal threads rest. In per-
manently sessile forms, the byssus is usually absent.

Gills. — On either side of the visceral mass above the foot and usually
extending from the palpi to the posterior adductors are the gills or ctenidia.
.In a general way the ctenidium is composed of a stem carrying a nerve and
blood-vessel, from which on each side leaflets or slender filaments are given
out laterally. In the more archaic types (Nucula, Yoldia, Solemya) these gills
are plate-like, not organically united except by the stem, though in some
cases attaining a solidarity as a mass, by the interlocking of very large cilia,
distributed in bands or patches on the opposed surfaces of individual plates.

These plate -like gills are termed foliobranchiate or protobranchiate.
According to their structure, other types of gills are intermediate between
these and the so-called " filibranchiate," in which the plates are elongated and
strap-like, and the " reticulate," in which the filaments are united by cross
conduits in a net-like manner. Attempts have been made to employ the
various types of gills as fundamental characters in classification, but experience
has shown that they cannot be depended upon as the exclusive basis of any
systematic arrangement.

Siphons. — When the mantle lobes are united, two posterior openings, more
or less tubular, are always present (Fig. 591). The dorsal tube, called the
dorsal or anal siphon, serves for the
discharge of water which has been
inhaled through the ventral or
branchial siphon, carried to the
gills, deprived of its oxygen and
edible particles, and then expelled.
The anal siphon also carries effete Sa^cnm ffrc,,.,, ^.4^ with oloswl lnailtlM

matters from the rectum, and some- e(1^es' showing foot oo, raotrndtag from the p.-iai opening,

, . , ,. , and aiuu m and branchial (/) siphons. Natural .size.

times ova are discharged in the same

way. The tubes are sometimes adherent or enclosed in the same envelope,
and sometimes separate to their base ; in general, however, a septum or
partition exists between the two passages, thus avoiding the mixture of the
two currents. The siphonal septum is frequently carried forward internally,
or supplemented by a junction of the gills in such manner as to form a

352

MOLLUSCA

SUB-KINGDOM VI

practically continuous partition between the anal and branchial regions
within the mantle. The siphons are always * contractile, and, except in
sedentary burrowers, usually retractile within the shell.

The siphons, being a local modification of the mantle margin, receive their
musculation from the same source. In general, the muscles have spread
inward, pari passu with the increase in length of the organ to be retracted,
and their insertion on the valve leaves an angular scar called the pallial sinus,
which is an important aid in classification of the minor groups. It has some-
times been assumed that the absence of this sinus was evidence of the
asiphonate character of the species, but the example of Lucina, Cuspidaria,
and several other siphonate forms which have no pallial sinus show that this
is not necessarily true. Formerly, when the character of the pallial line was
regarded as of prime importance, the Pelecypods with a sinus were called
Sinupalliata (Fig. 592), and those without, Integnpalliata (Fig. 593).

The Hinge. — The origin both of the hinge structure and the ornamentation
of the shell can be perhaps best understood by a consideration of what is

FIG. 592.

Lutraria elliptica, Roissy. Interior of left valve show-

and
hv,

ing pallial line (p) ; pallial sinus (s) ; anterior (ft) and
posterior (a') adductor scars ; and resiliifer (I).

Length ; ui, Height of the shell. 2/3 natural size.

FIG. 593.

•Crassatellites plumbea, Chern. sp. Interior of
left valve showing entire pallial line (m) ; anterior
(a) and posterior (a') adductor scars ; and resiliifer
(I). 2/3 natural size.

known regarding the archetype of the class, and by noticing the changes that
have since been introduced. The original protopelecypod was small, thin,
symmetrical, sub-circular or oval, with a short external ligament equally dis-
posed on each side of the beak along the hinge line. The mantle was not
uniformly attached to the shell along a pallial line, as in modern Pelecypods,
but adhered more or less irregularly and was not provided with extrusile
siphonal tubes. The adductor muscles were sub -equal, symmetrical, and
situated high up in the valves. The surface of the valves was smooth, or
(probably in connection with the development of tactile papillae on the mantle
edge) radiately ribbed. These conclusions are justified not only by inference
and by recent investigations on the morphology of the prodissoconch, but by
the characters of the most archaic Pelecypods, summarised by Neumayr under
the name of Palaeoconcha.

Since the general form of the Pelecypod depends upon its principal
anatomical characters (the size, number, and position of the muscles, the
presence, size, and character of siphons, byssus, etc.), then, to a certain
limited extent, especially in the modification of the primitive simple Palaeo-
conchs, it is plain that the differences of form would march with the respective
anatomical differences. For example, those forms which retained the simple

n.Ass i

PELECYPODA 353

open mantle and sub-equal adductors would continue to be of a rounded and
symmetrical shape; while those which tended to produce elongate siphons, or
in which marked inequality of the adductors was developed, would probably
present more elongate or triangular outlines. The differences of form would
necessarily react upon the developing hinge, from the inevitable operation of
physical laws, and thus tend to produce in connection with particular lines of
evolution of form, particular types of hin^r.

The recent researches of Bernard and Simroth have developed the fact
that in some Pelecypoda the ctenidium originates as a lateral plate, which
becomes transversely folded, and in which the reticulate form results from
subsequent perforations between the folds, and not from the concrescence of
originally separate filaments, as has been hitherto supposed to be the invari-
able mode.

Neumayr has shown that, among the Palaeoconcha, ribbing existed in
various species along the dorsal as well as the other margin, and that it pro-
duced denticulations there ; and that when these denticulations had become
a fixed specific character, the ribbing disappeared from the area above the
hinge margin.

In this way (as analogically in the recent Crenella et al.) the initiation of
the processes called hinge teeth began. Such projections, interlocking at a
time when the serrations of the other margin of the open valves could be of
little assistance in securing rigidity, offered a means of defence of the greatest
importance when fully developed by natural selection, one which would be
useful at every stage of development, but would increase in usefulness with
increase in size. In fact, this was just such a feature as would lend itself to
the fullest operation of natural selection. Once well initiated, its progress
was inevitable, and its variety and complexity only a question of time.

Very recent studies by Bernard of the development of hinge teeth in
nepionic Pelecypods of many groups, show that in most if not all Priono-
desmacea and some Teleodesmacea there is first developed on each side of the
ligament (or behind it in Ostrea] a series of transverse denticulations or
minute taxodont teeth, forming what has been called a provinculum or primi-
tive hinge, independent (so far as yet observed) of the permanent dentition.
The latter begins subsequently by the development of distinct laminae on
the hinge plate. In the Teleodesmacea, toward the ends of the hinge plate
the primitive lamellae originate below the provinculum or in its absence, and
grow proximally. The inner ends of the anterior lamellae become hooked,
and these hooks separate from the distal portions which remain to form the
anterior laterals, while the hooks develop into the cardinals, and the posterior
lamellae into the posterior lateral teeth. The facts point, of course, to the
provinculum as representative of the primitive hinge as observed in many
Palaeoconchs ; but the gap between the provinculum and the beginnings of
the permanent dentition, indicates a suppression of certain developmental
stages which only further researches can supply.

The dynamical origin of the shelly processes of the hinge, which we call
teeth, has only recently attracted attention. In this work Neumayr led the
way, and his contributions have been most valuable ; yet, as often happens
with pioneer work, he failed to grasp fully all the details of the subject, and
the nomenclature he proposed has required revision. Several groups or
kinds of teeth can easily be distinguished. These are not necessarily funda-
VOL. I 2 A

354

MOLLUSCA

SUB-KINGDOM VI

mental, since the teeth, being largely moulded by the, dynamics of their
situation, change with the influences to which their form is flue, and in course
of time may become obsolete from disuse (Anodon), or modified so as to
simulate the teeth of groups with widely different pedigree (Nucula, Mutela ;
Plicatula, Trigonia). In general, however, at any given time, the types of
teeth are good evidence of the relationship of forms to which they are
common, especially if the development from the younger stages of the species
under comparison proceeds along similar lines.

The modifications of the hinge now generally recognised are as follows : —
In the Taxodonta the hinge is composed of alternating teeth and sockets,
mostly similar, and frequently forming a long series, as in Area (Fig. 594, A)

FIG. 594.

Taxodont hinges. A, Area, with external ligament. B, Leila
with internal resilium.

FIG. 595.
Schizodont hin<,p<'.

Trigonia
Lain. Recent ; Aus-
tralia.

or Leda (Fig. 594, B). The Schizodonta have heavy, amorphous, variable
teeth, often obscurely divided into sub-umbonal (pseudocardinal) and lateral
(posterior) elements, as in Trigonia (Fig. 595), Unio (Fig. 596), and Schizodus.

In the Isodonta the original Taxodont
provinculum is often replaced in the adult
by a hinge structure derived from two
ridges (the " auricular crura ") originally
diverging below the beaks. This becomes,
in the most specialised forms, an elaborate
interlocking arrangement of two concentric
pairs of teeth and sockets, which cannot
be separated without fracture, as in Spon-
dylus (Fig. 669). In less specialised forms,
such as Pecten, the provinculum becomes
obsolete, and the crura only partially
develop.

The Dysodonta of Neumayr was originally a heterogeneous group, and the
term is now restricted to that division having a feeble hinge structure, whose
origin is more or less palpably derived from external sculpture impinging
upon the hinge line, as in Myoconcha (Fig. 597), Pachymytilus (Fig. 598), and
Crenella.

The preceding groups, together with the edentulous Solemyacea, constitute
the order Prionodesmacea, which is knit together by community of descent
still traceable in their anatomy.

The Pantodonta are a small group of Palaeozoic forms whose dentition

FIG. 596.

Schizodont hinge of Unio Stachci, Neumayr,
showing pseudocardinal and lateral teeth.
Pliocene, Slavonia.

CLASS I

PELECYPohA

356

Bayeux,

Vi-

Calvados.

Dysodont hinge of /'«<•// </»n// /'/».-• /*/
d'Orb. Coral Rag ; Coulange - sur - Yonne,
France. 2/3.

Isocardia (Fig. 757), Tridacna, and Canlinin

]>;u t.ikes of the synthetic character of the more archaic forms, while fore-
shadowing the future Teleodont types. In this group the laterals may
exceed a pair in a single
group, which is never the
case in the modern types.
Orthodontiscus and Allodesma
are examples.

The Diogenodonta are the
modern and perfected forms
in which there are differen-
tiated lateral and true car-
dinal teeth upon a hinge
plate, the former never ex-
ceeding two nor the latter
three in any one group.
Astarte (Fig. 705), Crassatel-
lites (Fig. 593), and CorUcula
(Fig. 712) are examples.

The Cydodonta exhibit
extreme torsion in their Goidf. Lower poute;
dentition, which curves out
from under the beaks and is
not set upon a flat hinge plate.
(Fig. 752) are examples.

In the Teleodonta are found the most highly perfected types of hinge.
The characters of the less specialised forms hardly differ from those of the
Diogenodonta, but they are placed here on account of their obvious affinities
as shown by other characters. The most specialised forms add to the ordinary
cardinal series of the Teleodesmacea (10101) either a roughened area, as in
Venus ; a series of extra cardinals, as in Tivela; or accessory lamellae, as in
Mactra, making the hinge more complicated or efficient. Cytherea (Fig. 760),
Mactra (Fig. 775), Venus (mercenaria), and Tivela are examples.

Several of these forms were included by Neumayr in a group called Ues-
modonta, which he founded on such types as Mactra under a misapprehension
as to the character of the hinge ; almost all of the others were included in
his Heterodonta, which, construed strictly, would take in all dentiferous
Pelecypods, since the alternation forming its essential character is inseparable
from the possession of functional teeth.

The Asthenodonta comprise borers and burrowers in which the teeth have
become obsolete from disuse. Corbula (Fig. 779), Mya (Fig. 778), and Pholas
(Fig. 784) are illustrative types. In the last-named a remarkable develop-
ment of the sub-umbonal attachment of the mantle has produced a myophore
which is sometimes wrongly interpreted as a tooth. The exceptional develop-
ment of this feature is explained by the dynamics of Pholad existence.

The above 'groups form the c-rder Teleodesmacea, and dentally are intimately
related. Recent studies by Bernard l as to the genesis of individual teeth
among members of this order show great uniformity in the early stages.
But inasmuch as these observations are dependent upon the mode of growth

1 Bernard, F., Sur le developperuent et la morphologic de la coquille chez les larnellibraiiches
(Bull. Soc. Geol. France [3], XXIII.), 1895, and XXIV., 1896.

356 MOLLUSCA SUB-KINGDOM vi

in highly specialised Pelecypods, in which the development of teeth is largely
secondary, care must be taken not to confound these processes with those by
which hinge teeth were originally initiated in edentulous Protopelecypods.

Finally, in the Anomalodesmacea we have a tribe of burrowers which have
preserved to the present day some of the features which characterised the
edentulous Protopelecypods of ancient geological time. The small teeth of
the nearly edentulous hinge may sometimes be associated with the submersion
of the resilium and the development of a chondrophore, but in other cases
they may be the remnants of hinge teeth acquired in the ordinary way early
in the geological history of the group.

Dental Formulae. — For the purpose of recording compactly the number
and character of the teeth in adult Pelecypods, a formula has been suggested
by Dr. Steinmann, which, somewhat amplified, is as follows : —

Let L represent the left and R the right valve, and the teeth be repre-
sented by units ; the sockets into which teeth of the opposite valve fit by
zeros ; the resilium or chondrophore by C ; the laterals by 1 ; the clasping
laminae which receive the laterals by m, if single ; if double, by m2. Where
two Taxodont rows meet on one hinge margin and are not separated by a
resilium, as in Pectunculus, let their junction be marked by a period. Obsolete
or feeble teeth may be represented by the italicised symbol for normal teeth.
For amorphous, interlocking masses, which cannot be classified as teeth, and
are of varied origin, the symbol x is adopted. The enumeration begins at the
posterior end, and the right-hand end of the formula is always anterior.

Thus, types of Teleodont dentition may be represented as follows : —

Astarte borealis, p?^^ ; Crassatellites antillarum, ™c^;*. l ; Venus mercenaria,

LxOlOlO RtHllWim rt L el

P 1Q1 (in this case x represents the rough area below the ligament).

In investigating the genesis of the individual hinge teeth in various
genera of the Teleodesmacea, Messrs. Munier - Chalmas and Bernard have
adopted the following formula, which expresses at once the origin and
position on the hinge of the several teeth. In the majority of cases the
teeth appear to be derived from two primitive pairs of lamellae in each valve,
one pair anterior and one posterior. Each adult tooth is designated by
an arabic numeral corresponding to the primitive lamella from which it is
derived, with a for the anterior and b for the posterior tooth when a single
primitive lamella gives rise to two teeth. The laterals are counted from
below upward in Roman numerals, the odd numbers belonging in every case
to the right, and the even numbers to the left valve. If it is necessary to
name a socket it receives the designation of the tooth which occupies it, supple-
mented by an accent ('). A and P stand for anterior and posterior, L for lateral,
and CA for cardinal teeth. Finally, if a tooth disappears, its place is indi-
cated by a zero with an index showing which particular tooth it was. The
numeration of the cardinals always begins with the right median cardinal
tooth. Thus, CA1= median cardinal of the right valve, CA26 = left median
cardinal derived from the posterior part of primitive lamella number two ;
LA I = ventral anterior lateral, LP III = dorsal posterior lateral, etc.

Ligament. — The ligament which unites the two valves, as stated above, is
primitively continuous with them as the uncalcified part of the primitive
pellicle secreted by the original shell gland ; it is therefore neither external
nor internal. With its subsequent differentiation, and the thickening of the

CLASS i PELECYPODA 3:, 7

valves by calcification deposited about it, it occupies a depression in tin-
cardinal margin which Bernard has regarded as internal. In a sense it is
internal, but its position at this stage is not significant, and there is no^
fundamental difference between the cases. The differentiation in function
and structure which we find in the adult between the ligament, properly
so-called, and the " internal ligament " or resilium, is a later development.

The ligament may be regarded as a fundamental character of Pelecypods,
and is universally present, though in some cases as a mere degraded rudiment
(Pholadacea) • it may be separated from the valves and functionless (Chlamy-
doconcha), or present only in the young stages and lost through specialisation
due to the sessile habit (Budistae).

As the most important factor in the mechanism of the valves, the liga-
ment has undoubtedly developed with the evolution of the class, and its
chief modifications date from the earliest period in the life- history of the
group. The function of the original ligament was that of an external link
between the valves having the essential nature of a C-spring. That is, the
insertion of the ligament edges on the cardinal margins, or, at a later period,
on thickened ridges or nymphae by which these margins are reinforced to bear
strains, resulted in the following conditions : — The valves being held together
and, in closing, approximated by the contraction of the adductor muscles, the
preservation of their precise apposition, marginally, is due to a rotary motion,
exerted along the axis of the ligament, which pulls the attached edges of the
ligament nearer to each other and exerts a strain on its cylindrical exterior.
This operation, with a thin ligament, involves a tensile strain on the whole
cylinder ; with a thick ligament the external layers are strained and the
internal layers compressed, so that, to the tensile elasticity of the external
layers is added the compressional elasticity of the internal portion. The
result of the differing strains to which the several layers of the ligament are
subjected brings about a difference of structure, and, whenever the ligament
becomes deep-seated, there is a tendency for the respective parts to separate
along the line where the two sets of strains approximate. We then have two
elastic bodies, operating reciprocally in opposite directions, the outer or liga-
ment proper tending to pull the valves open to a certain distance correspond-
ing to its range of tensional elasticity ; and the other or resilium (for which
the objectionable terms " cartilage " and " internal ligament " have been used)
tending to push them open to an extent corresponding to its range of ex-
pansion.

The ligament proper is of a more or less horny nature, tough, and semi-
translucent beneath its external surface. When dry it has a vitreous fracture,
and often shows hardly any fibrous texture.

The resilium is distinctly lamellar or composed of horny fibres, which are
apt to give a pearly sheen to its broken surface. There is often a more or
less extensive intermixture of lime in its substance, which may be diffused, or
may be especially concentrated along the median plane. As may be seen by
examining the unbroken resilium (as in Mactra), this organ in such cases has
something of an hour-glass shape ; the ends which fit into the " cartilage pits "
or resilifers being more expanded than the centre between them. The deposit
of lime in the form of an accessory shelly piece, usually termed the ossiculum
or lithodesma, serves for the reinforcement of the resilium.

For the type of ligament which extends on both sides of the beaks,

358 MOLLUSCA SUB-KINGDOM vi

Neumayr adopts the designation amphidetic ; and* for the more perfected type
which has been withdrawn wholly behind the beaks, he employs the term

opisthodetic (Fig. 599). Glycimeris
(HHlXt offers a conspicuous type of the
amphidetic ligament ; Tellina and
Venus exemplify the opisthodetic
arrangement. In many bivalves
a lozenge - shaped cardinal area
extends amphidetically between
the beaks, while the ligament is
wholly posterior, being visible as
an oblique triangular space, with
FlG- 5"- its apex at the umbonal point

Homomya calciformis, Ag. With well-preserved external, nn,l :<.„ VISIQP nt flip Viino-P II'TIP a«
opisthodetic ligament. Lower Oolite ; near Bayeux. a/3. ancl lts base at tne ning6 lme> aS

in Avicula. Nearly every stage

in the recession of the ligament can be observed, from truly central to
posterior, in Lima and its allies.

The most perfected type of ligament is that which may be compared to a
cylinder split on one side, and attached by the severed edges, one edge to each
valve. This type is known as parivincular (Tellina, Cardium) • its long axis
corresponds with the axis of motion or vertical plane between the valves, and
in position it is usually opisthodetic. Another form is like a more or less
flattened cord extending from one umbo to the other (Spondylus, Lima), with
its long axis transverse to the plane of the valve margins and the axis of
motion. This is called alivincular ; it may be central or posterior to the
beaks, but, unless very short, is usually associated with an amphidetic area.
Lastly, a third form must be noted which consists of a reduplication of the
alivincular type at intervals upon the area (Perna, Area, Fossula), either
amphidetically or upon the posterior limb of the cardinal margin. This is
designated as multivincular, and is developed out of the alivincular type.

In some forms with a rigid hinge and internal resilium, the ligament may
degenerate into its archaic epidermic character, as in some species of Spondylus.
It is impossible to draw a sharp line between these and similar forms in which
the ligament is not quite reduced to the state of epidermis, as in some species
of Ostrea. The cardinal area above referred to is in part the morphological
equivalent of the lunule of Teleodont Pelecypods. In general, when the
ligament has become opisthodetic, the remnant of the area in front of the
beaks forms the lunule and may be called prosodetic. The amphidetic area
is an'archaic feature which has been lost by the more specialised types of
modern bivalves, and its gradual disappearance may be traced in various
Prionodont genera.

The separation of the ligament and resilium has been described as due to
mechanical causes.1 In cases where the resilium becomes submerged from
between the valves, the area of attachment of its ends in thin-shelled forms is
more or less thickened and assumes a spoon-like form projecting from the
hinge plate, termed the chondrophore or resiliifer; this is often reinforced by a
special prop or buttress called the clavicle. It has been suggested by Neumayr
that part of the armature of the hinge, in the shape of teeth, is due to deposits

1 Amer. Journ. Science [3], vol. XXXVIII., 1889, pp. 448-451.

I'KLKCYPODA

350

made parallel to or induced by the presence of the chondrophore and
resilium.

There is some reason to think that the presence of the resilium in Fecten
and Spondylus may be connected with those changes of the auricular mini
which lead to the assumption of dental functions by the latter. But it is well
known that submergence of the resilium occurs independently in many unre-
lated groups of bivalves ; and it is probable most of them were previously
dentiferous and still retain their teeth, although more or less modified or
displaced, while the edentulous genera seldom show any teeth which appear
to owe their existence solely to the presence of a chondrophore. The nearest
approach to a hinge composed of dental laminae of such an origin is found in
Placuna, Placenta, and Placunanomia, together with the Spondylidae already
mentioned.

Classification. — The class Pelecypoda, which comprises about 5000 recent
and twice as many fossil species, appears to be divisible into three or-
dinal groups : Prionodesmacea, Anomalodesmacea, and Teleodesmacea ; of which
the third represents the most perfected and developed (though not always the
most specialised) modern type of bivalve. There seems little reason to doubt
that all these orders are descended from a Prionodesmatic radical or prototype,
and that for various reasons the first and second retain more evident traces of
this origin than the third.

For convenience of comparison the characteristics of these orders will be
stated here.

Prionodesmacea. — Pelecypods having the lobes of the mantle generally separated, or,
when caught together, with imperfectly developed siphons ; the soft parts in general
diversely specialised for particular environments ; the shell structure nacreous and prismatic,
rarely porcellanous ; the dorsal area amphidetic or obscure, rarely divided into lunule and
escutcheon, and when so divided, having an amphidetic ligament ; ligament variable, rarely
opisthodetic ; nepionic stage usually with a taxodont provinculum ; permanent armature of
the hinge characterised by a repetition of similar teeth upon the hinge line, or by amorphous
schizodont dentition ; habits active, sessile or nestling, not burrowing ; monoecious or
dioecious.

This group, originating with the earliest forms, has retained many archaic
features through immense periods of geological time, although occasionally developing
remarkable and persistent specialisations. Notwithstanding most of its subdivisions
have arrived at a notable degree of distinctiveness, intermediate forms of ancient date
connect them all, more or less effectively, with the parent stem.

Anomalodesmacea. — Pelecypods having the mantle lobes more or less completely united,
leaving two siphonal, a pedal, and sometimes a fourth opening between them ; siphons well
developed, always at the posterior end of the body ; two subequal adductor muscles ; the
shell structure nacreous and cellulo-crystalline, rarely with ;i prismatic layer ; the areaamphi-

hermaphrodite, and marine.

This group is intimately related to many of the Palaeoconcha, except as regards the
presence of a pallial sinus. It retains many archaic features, and includes several of
the most specialised modern forms. Through the Anatinacea it approximates the
Myacean Teleodesmacea. It is peculiar in the possession of a lithodesma. and in the
structure of its gills and hinge. The forms with a reticulate gill have it of a different
type from the reticulate gills of the other orders; those which retain a modified
foliobranch gill have it different from the foliobranch gill of Prionodesmacean groups.

360 MOLLUSCA SUB-KINGDOM vi

There are no forms with a filibranchiate gill, or with a typically fully developed
reticulate gill.

Teleodesmacea. — Pelecypods with reticulate gills, the ventricle of the heart embracing
the rectum ; having the mantle lobes more or less connected and usually possessing developed
siphons ; the adductors practically equal ; the shell structure cellulo-crystalline (porcellanous)
or obscurely prismatic, never nacreous ; the dorsal area, when present, always prosodetic or
divided into lunule and escutcheon ; ligament opisthodetic, with or without separate resilium ;
without a lithodesma, rarely with external accessory shelly pieces ; nepionic stage usually
without a Taxodont provinculum ; permanent armature of the hinge characterised by the
separation of the hinge teeth into distinct cardinals and laterals ; the posterior laterals,
when present, placed behind the ligament ; the animals active or nestling, sometimes sessile,
but rarely sedentary burrowers, rarely inequivalve, usually possessing a hinge plate and a
pallial sinus ; sexes usually separate.

It is doubtful if this group is represented in the Palaeozoic rocks, especially below
the Carboniferous, though genera belonging to it are foreshadowed by some of the
Palaeoconchs. Although most of the Teleodonts live embedded in the surface of the •
sea-bottom, they retain their ability to migrate, and only a few extremely specialised
forms inhabit permanent burrows of their own construction. They are sometimes
commensal in the burrows of other animals. Similarly, few of them fix themselves
permanently by a byssus, although often byssiferous, especially when young. With
the exception of a few specialised forms they possess a pair of direct and reflected
branchial laminae on each side of the body, frequently united behind the foot, forming
an fnal chamber ; the two sets on one side usually of unequal size, and of the reticulate
type. None are known with typically foliobranch or filibranch gills, although some
abyssal forms have archaic sub-foliobranchiate ctenidia.

There remains a small group of fossils, difficult to refer to a place in the system,
yet characterised by several features in common ; these have been named by Neumayr
Palaeoconcha, and are defined by him as follows : —

Palaeoconcha. — Prototypic Pelecypods, with thin shells, a simple or obscure pallial line,
sub-equal adductor scars placed high in the valves ; dorsal area absent or amphidetic ; liga-
ment external, variable ; hinge margin edentulous or with polymorphous teeth formed by
modifications of the margin and not set upon a hinge plate.

While the forms included here are not always actually the most ancient, yet in
their modifications they indicate clearly the origin of many subsequently developed
structures found in Pelecypods of a more modern type ; and owing to their undifferen-
tiated polymorphic character are difficult to assign a place in any classification based
on more highly developed forms. There is little doubt that some of these show Taxo-
dont affinities, and others recall Pholadomya ; but the final discussion of these puzzling
forms awaits greater knowledge of them and other early bivalves. It is to be under-
stood that the places assigned them in the present systematic arrangement must be
more or less provisional. Neumayr included in this group the following families : —

Vlastidae. Praecardiidae. Solenopsidae.

Cardiolidae. Silurinidae. Grammysiidae.

Antipleuridae. Protomyidae (including possibly Posidonomyidae.

Lunulicardiidae. the recent Solemya). Daonellidae.

The pelagic Planktomya Henseni, recently described by Simroth, presents many of
the characteristics of the Palaeoconchs. The posterior cardinal margin is denticulate,
the ligament internal, and the gills are represented by a single lateral plate parallel
with the longer axis of the shell on each side ; a type elsewhere only known in con-
nection with the younger stages of Scioberetia.

ORDER i PRIONODESMACEA 861

Order 1. PRIONODESMACBA. Ball.

I. (PALAEOCONCIIA, ]>.j>. Xeumayr).1
Family 1. Solemyacidae.

Shell Soleniform, equivalve, low -beaked, edentulous, gapiini, >/•//// the anterior end
longer and the epidermis conspicuous, exceeding the valves ; area obscure or none ; ligament
amphidetic, parivinevliart /"•<•«//////// internal posteriorly; mantle lobes united ventrally,
attached in front to the epidermis and valves by a broad surface, leaving no distinct pallial
line; a single posterior siphonal and anterior pedal foramen in the mantle ; adductors
sub-equal, with a thickened ray in front of the posterior scar : uniuml dioecious, marine,
burrowing. Silurian to Recent.

Solemya, Lam. Carboniferous to Recent, rare in all horizons. 1 0rthodesma,
Hall. Silurian. Janeia, King, shorter and less inequivalve, may include most of the
Palaeozoic species hitherto referred to Solemya. Clinopistha, Meek and Worthen,
from the Carboniferous, is also allied, and Dystactella, Hall, is united with it by Zittel.
Phthonia, Hall, from the Devonian, is placed here by Ulrich.

Family 2. Solenopsidae. Neumayr.

Shell thin, elongate, equivalve, with very anterior beaks ; the hinge edentulous, ligament
parivincular, external; pallial line not sinuated ; a ridge or groove radiating from the
beak to the lower posterior angle of the valves. Marine. Silurian to Trias.

Sanguinolites, M'Coy. Elongate, obliquely truncate behind ; beaks low, sculpture
of concentric or broken lines, anterior
adductor scar buttressed by a ridge.
Carboniferous.

Promacrus and Prothyris, Meek.
Carboniferous. FIG. coo.

Arcomyopsis, Sandb. Somewhat Solenopris pelagico, Goldf. Devonian ; Eifel District,
curved, with prominent beaks ; obliquely

truncate behind ; posterior area radially, the rest of the surface concentrically
sculptured. Devonian.

Orthonota, Conrad ; Orthodesma, Hall. Silurian.

Solenopsis, M'Coy (Fig. 600). Very long, scabbard-shaped, smooth ; anteriorly
short and rounded, gaping behind. Devonian to Trias.

Family 3. Vlastidae. Neumayr.

Shell thin, very inequivalve, beaks elevated, hinge line edentulous, arched, meeting at an
obtuse angle beneath the beaks, leaving a dorsal opening ; surface smooth or concentrically
striate.

The two genera Vlasta and Dux (Vevoda), Barrande, from the Silurian of Bohemia
(Etage E 2), constitute this family.

Family 4. Grammy siidae. Fischer.

Shell thin, equivalve, oval, or elongate, with the beaks sub-central to anterior; hinge
edentulous, sometimes thickened. Ligament parivincular, external; pallial line not
sinuate; surface smooth or concentrically sculptured. Silurian to Carboniferous.

1 [The terms Palaeoconcha, Taxodonta, Schizodonta, etc., preceded by Roman numerals, un>
retained here merely as convenient descriptive appellations, and are in nowise to be regarded as
possessing systematic values.]

362

MOLLUSCA

SUB- KINGDOM VI

Grammysia, Vern. (Sphenomya, Hall), (Fig. 601)* Shell elongate-ovate, concen-
trically sculptured, with a deep lunule ; cardinal margin thickened, edentulous ;

surface with several radial
grooves. Silurian and De-
vonian. Protomya, Hall, is
similar but without the
grooves.

Leptodomus, M'Coy, Sil-
urian ; Elymella, Glossites,
Euthydesma, Paleanatiiw ,
and ? Tellinopsis, Hall ;
Devonian.

Cardiomorpha, de Kon.

Grammysia HumiUoneim$,Verii. Spirifer Sandstone (Lower Devonian) ; ^ , • a , i •, •> -,
Lahnstein, Nassau (after Sandberger). Oval, inflated, beaks almost

anterior, conspicuous, ad-
jacent, prosogyrous ; hinge line thin, arched. Silurian and Carboniferous.

Isoculia, M'Coy. Like the preceding, but with coarse concentric sculpture.
Carboniferous.

Other Carboniferous genera are Broeckia, de Kon.; Chaenomya, Meek; Sedgwickia,
M'Coy ; and Edmondia, de Kon. The last is like Cardiomorpha, but gapes in front,
with a narrow ridge below the beaks.

The Cambrian Fordilla, Barrande, earliest of bivalves if a Mollusk, may possibly belong
to the Crustaceans near Esthcria. It is minute, oval, somewhat arcuate, and concentrically
striated. Potsdam.

What appears to be a genuine Pelecypod, and so far the only one except Fordilla which is
known from the Cambrian rocks, is Modioloides priscus, Walcott. It
is transversely oval, with sub-central, incurved beaks, and an anterior
adductor scar visible Avithin an apparently simple pallial line. It is
minute (2 mm. long), and known by an internal cast from the Lower
Cambrian of Washington County, New York. The Ordovician
Redonia, Rouault, is not dissimilar.

Family 5. Cardiolidae. Neumayr.

Shell equivalve, inflated, obliquely ovate, with prominent beaks,
and edentulous hinge ; sculpture often radial, or sometimes of con-
centric ridges, which may be confined to the leaks. Silurian and
Devonian.

Cardiola, Brod. (Fig. 602) : Gloria, Barrande ; Eopteria
(? Euchasma), Billings, from the Ordovician, may also belong
here.

FIG. 60-2.

Cardiola cornucopiac,
Goldf. Devonian ; Ebers-
reuth, Fichtelgebirge. a/i-

Family 6. Antipleuridae. Neumayr.

SJiett very inequivalve, without gape below the beaks ; hinge obscurely Taxodont, with an
amphidetic area and predominantly radial sculpture. Silurian.
Antipleura, Dualina, and Dalila of Barrande.

Family 7. Praecardiidae. Neumayr.

Shell equivalve with Taxodont dentition and usually strong radial sculpture. Silurian
and Devonian.

This family contains the following genera of Barrande from the Silurian of
Bohemia : — Praecardium, Paracardium, Puella, Pentata, Buchiola (Glyptocardia, Hall),
Praelucina, Regina, Praelima ; to which Neumayr adds Pleurodonta, Conrath, and
Panrarca, Hall. It is possible that Silurina, Barrande, regarded by Neumayr as the

ORDER I

PRIONODESMACEA

type of a distinct family, may also be included. It is distinguished by its feebler
structure ami a dorsal radial groove near the cardinal bonier.

II. TAXODONTA. Neumayr (emend.)
Superfamily 1. NUCULACEA.

Shell of variable form, closed veittrnlhf, njuii'iifrf, /'•//// a *inootli •/ /"" rcous or

porcellanous with t ubuliferous external prismatic layer ; area obscure, or none, when present
divided into lunule and escutcheon; ligament variable, amphiilttir : (fills
foliobranchiate; both adductors present and sub-equal; foot grooved ami
reptary, not byssiferous ; marine.

I^imily 8 ? Ctenodontidae. Dall.

Shell Nuculiform, with the, teeth in a continuous arched series ; no
area ; L ligament external, alivincular, without an external resiiimu :
pallial line simple^ Ordovician and Silurian.

Ctenodonta, Salter (Tellinomya, Hall p.p.), (Fig. 603). Oval, smooth '^"'}
or concentrically striate, in the later horizons sometimes Ledaeform. Hall).
Ordovician and Silurian.

Cucullella (M'Coy), Fischer. Ovate, thin-shelled, with a straighter hinge line and
a radial buttress to the anterior adductor. Silurian.

Family 9. Nuculidae. Adams.1

Shell compact, closed, with tJie teeth in two series meeting below the umbones, separated

by a chondrophore ; area represented by an obscure
lunule and escutcheon; no ligament, but a wholly
internal, amphidetic, alivincular resilium ; internal
layer of shell nacreous; mantle lobes free, with nut
siphons ; pallial line simple. Ordovician to Recent.

Nucula, Lam. (Nuculana, Link), (Fig. 604).
Oval or triangular, concentrically or reticulately
sculptured. Silurian to Recent. Represented by
FIG. 604. over 200 fossil and half as many recent species.

A , Nucula stngiiata, Goidf. Upper Trias ; Acila, Adams. With divaricate sculpture.

St. Cassian, Tyrol, l/,. B, N. nucleus, Linn. T

Miocene ; Grussbach, near Vienna, i/,. Lower Cretaceous to Recent.

Family 10. Ledidae. Adams.1

Shell as in the Nuculidae, but elongated with the ligament variable, the resilium sometimes
external or absent, the internal shell layer sub-nacreous or
porcellanous, the ends of the shell partly gaping ; the mantle
lobes more or less united; with complete, sometimes elongate
siphons ; pallial line usually sinuated. Silurian to Recent.

Cleidophorus, Hall (Adranaria, Mun. Chalrn.), (Fig.
605). Shell rostrate, the anterior side shorter, with an
internal radial buttress. Silurian and Devonian.

Ci/therodon, Hall. Silurian and Devonian. ? Redonia,
Rouault ; Gadomia, Trornelin ; Tellinomya, Palaeoneilo,
Hall ; Anuscula, Barr. ; and Myoplusia, Neumayr. Silurian.

Leda, Schum. (Figs. 606, 607). Shell rostrate, elongate, often keeled, concentri-
cally striate ; hinge as in Nucula ; pallial sinus small. Silurian to Recent.

1 Verrill, A. E., and Bush, K. J., Revision of the genera of Ledidae and Nuculidae (Amer. Journ.
Science [4], vol. III. pp. 51-63), 1897.

Fio. 005.

drlilo/thorH* ruJti-iitiis, SandK

364

MOLLUSCA

SUB-KINGDOM VI

Yoldia, Holler (Fig. 608). Shell thin, wide, and more or less gaping behind,
hinge as in Nucula. Cretaceous to Recent.

FIG. 606.

Leda rostrata, Lam.
sp. Middle Jura ;
Milhaucl, Aveyron.

Vi-

FIG. 607.

Leda Deshayeslana, Duch.
Oligocene ; Rupelmonde,
Belgium, i/j.

FIG. 608.

Yoldia arctica, Gray.
Pleistocene ; Bonus-
lan, Sweden, i/x.

FIG. 609.
Nuculina ovalis,
Wood sp. Mio-
cene; Forchtenau,
near Vienna.

Nuculina, d'Orb. (Fig. 609), Nuculiform, hinge teeth few and. discrepant ;
with large lateral tooth and external ligament. Tertiary and Recent.

Malletia, Desm., and Tindaria, Bell. Yoldiform and Nuculiform respectively, but
without internal chondrophore. Tertiary and Recent.

Superfamily 2. ARCACEA. Deshayes.

Shell of varied form, usually with a pilose epidermis, porcellanous, with tubuliferous
non-prismatic external layer ; area typically amphidetic, ligament external, ali- or multi-
vincular ; gills fllibranchiate, with the filaments usually reflected ; mantle lobes free, without
siphons, the pallial line simple; foot variable, deeply grooved, byssogenous ; marine or
fiuviatile.

Family 11. Parallelodontidae. Dall.

Shell Arciform, with the posterior hinge teeth elongated, tending to be parallel to the
margin ; ligament multivincular. Carboniferous to Recent.

FIG. 610.

ParaUelodon Hirsonensis, Morris and
Lye. Great Oolite ; Minchinhampton,
England. 1/1-

The ancient forms of this group appear to connect
with the Pteriacea through Pterinea, and with Area
through Cucullaea. The recent forms, which from
their shell characters have been referred to Macrodon,
are all small and abyssal. The relationship of this
family to the Arcidae is very intimate but not
exclusive.

ParaUelodon, Meek (Macrodon, Lycett), (Fig.
610). Shell elongate, sub-quadrate, with amphi-
detic area, and prominent, rather anterior beaks.
Anterior teeth transverse or flexuous, posterior long and parallel to the hinge line.
Devonian to Tertiary;, maximum in Coal Measures.

°

ORDER i PRIONODESMACEA 365

Grammatodon, Meek and Worthen, arid Nemodon, Conrad, are allied. Carbonarca,
Meek and Worthen. Beaks inflated, curved, angular behind ; hinge margin curved,
with two oblique teeth. Carboniferous.

Cucullaea, Lam. (Fig. 611). Shell inflated, trapezoidal ; hinge teeth in the centre
of the hinge short, transverse or oblique, the terminal teeth on each side longer, sub-
parallel to the hinge line ; posterior adductor usually supported by a radial elevated
lamina or buttress. Jura to Recent ; maximum in Mesozoic.

Cucullaria, Desh., of the Eocene, and Idonearca, Conrad, are closely allied.

Family 12. Cyrtodontidae. Ulrich.

Shell equivalve, short, usually heavy, convex, and earthy, without persistent epidermis,
area small, ligament parivincular ? ; hinge teeth transitional between the Parallelodon and
Dysodont type ; adductor scars sub-equal, the posterior larger but less impressed. Ordovician
to Devonian.

These forms are evidently intermediate in character. They recall Limopsis among later
types, are nearly related to the Parallelodontidae, but have not the multivincular ligament ;
the hinge has Dysodont elements, but the difference of texture and epidermis stand in the
way of assimilating them with the Mytilacea.

Cyrtodonta, Bill. (Cypricardites, p.p. Conrad ; Megalomus, Hall). Shell rounded,
moderately ventricose, with rather tumid, incurved, anterior beaks ; area narrow and
obscure ; cardinal teeth two to four, obliquely curved or horizontal ; lateral teeth near
the posterior end of the hinge elongate, strong, curved, or oblique ; pallial line simple.
Anterior adductor set on the wall of the valve. Silurian.

Cypricardites, Conr. (Palearca, Hall). Five cardinal teeth present, the anterior
largest. Silurian.

Vanuxemia, Bill. Beaks more nearly terminal, anterior adductor scar excavated
out of the hinge plate. Ordovician.

Whitella, Ischyrodonta, Ulrich ; and Matheria, Bill. Silurian.

Family 13. Limopsidae. Dall.

Shell Pectunculoid, equivalve, or nearly so ; the ligament alivincular, partly immersed,
its socket approaching a chondrophore ; area small ; foot long, narrow,
yrooved, byssiferous; otherwise as in Arcidae. Trias to Recent.

These forms precede the typical Area and have a special facies of their
own. The two dental series of the hinge are often discrepant in character
or direction, recalling the Parallelodontidae.

Limopsis, Sassi (Fig. 612). Small, rounded, or oval, recalling
Glycimeris, except for the alivincular ligament. Trias to Recent.

Trinacria, Mayer (Trigonocoelia, Nyst). Like Limopsis, but tri- FIG. 612.
angular, with the posterior slope keeled. Eocene. Cnisma, Mayer, Livwpsis aurita,
from the Eocene, appears to be related.

Family 14. Arcidae. Dall.

Shell trapezoidal or rounded, with the posterior side longer ; ligament usually multi-
vincular; hinge typically Taxodont, with the teeth in two similar series, meeting below the
beaks, and approximately vertical to the margin of the valve ; foot stout, short, deeply
grooved. Jura to Recent.

Most of the Palaeozoic ^4rca-like forms are probably Parallelodontidae, and the typical
Areas are preceded by Pectunculoid forms. The convergence of the types of Arcacea as we
recede in geological time is very marked, and their relations to the Nuculacea are evident in
spite of the later developed differences.

366

MOLLUSCA

SUB-KINGDOM

Area, Lam. (type A. Noae, Lin.) Shell trapezoid,.equivalve, with a wide amphi-
detic area, distant conspicuous beaks, and radial sculpture ; a wide byssal gape ; a
long, straight, transversely dentate hinge line, with many small similar teeth.
Tertiary and Recent. Used in the wider sense, to include all the groups of Arcidae,
there are some 200 living and 300 to 400 fossil species.

Sub-genera: Harbatia, Gray (Fig. 613); Scapharca, Noetia, Anadara (Fig. 614), and
Argina, Gray ; Scaphula, Benson (fresh-water), etc.

Isoarca, Miinst, (Fig. 615). Shell smooth, inflated; beaks full, incurved; hinge
line with rather amorphous dentition. Upper Jura and Lower Cretaceous.

Arm (Jlnrljutia) barbata. Linn,
cene ; Grund, near Vienna, 1/1-

Mio-

FIG. 614.

Area (Anadara) diluvii, Lan
Pliocene ; Sienna.

FIG. 615.

Area (Isoarca)} cordi-
formis, Ziet. ' Upper
Jura ; Nattheim, Wur-
teinberg. 1/1-

Glycimeris, Da Costa (Pectunculus, Lam. Axinea, Poli), (Fig. 616). Rounded and
almost symmetrical. Basal margin dentate ; area as in Area, but shorter ; ligament

FIG. 616.
(flycimeris obovatus, Lam. Oligocene ; Weinheim, near Alzey. 1/1-

multivincular ; teeth oblique, in an arched series, interrupted during growth by the
subsidence of the areal margin. Cretaceous to Recent ; maximum in Miocene.

III. SCHIZODONTA. Steinmann (emend.)
Superfamily 3. PTERIACEA. Ball.

Shells of varied form, frequently alate, with a nacreous or sub-nacreous inner and pris-
matic outer layer ; the epidermis seldom conspicuous ; area amphidetic ; ligament variable,
usually not parivincular ; gills filibranchiate or reticulate, usually reflected ; mantle lobes
free, without siphons ; pallial line simple ; the anterior adductor smaller, or frequently

OUDKR T

PRIONODESMACEA :u>7

obsolete in the adult, t!i<>u<ih present in the young ; generally byssiferous ; hinge Schizodont
or edentulous. The young sometimes showing a distinct nepionic stage. Marine.

Family 15. Pterineidae. Dull.

Shell Pteriiform, bialate, dimyarian, the anterior adductor smaller ; inequivake, vet-y
inequilateral ; dentition obscure; ligament amphidetic, external, multivincular (?) ; the byssus
passing through a notch in tlo smulhr rnlve. Ordovician to Devonian.

In Picrinca and its allies we have the first indications of divergence of what ultimately
became Taxodont and Schizodont dentition. From this assemblage, as indicated by ,J;u kx.n,
a large proportion of the Prionodesmacea have diverged in various directions. It is probable
that from this source the filibranchiate Taxodonts have sprung, rather than directly from the
ibliobranchs.

Rhombopteria, Jackson (Fig. 617). Posterior wing separated from the body of the
valve by a shallow sinus ; anterior wing short ; teeth obscure, the posterior elongated.
Silurian.

Pterinea, Goldf. (Fig. 618). Left valve convex, right valve flat ; hinge plate long,
broad, auriculate before and behind ; area amphidetic, grooved ; ligament parivin-

I

FIG. (517.

/,Vm,,,/,,r/o-/</ mira, FIG. 61S.

Han. sj>. Silurian (E); A, Pterinea laevis, Goldf. Devonian; Niederlahnstein, Nassau. Interior of left

Prague(after Jackson). valve, i/i« B, P- lineata, Goldf. Same locality; external view.

cular (?) ; anterior teeth obscure, transverse ; the posterior elongate, nearly parallel to
the cardinal margin, depressed behind. Posterior adductor scar large, the anterior
small but strong, inserted below the anterior wing. Silurian to Carboniferous ;
particularly abundant in the Devonian of Europe and America.

Actinodesma, Sandb. (Glyptodesma, Ectenodesma, Hall ; Dolichopteron, Maurer). Like
Pterinea, but with the wings elongated and pointed. Devonian.

Leptodesma, Hall ; Kochia, Freeh (Onychia, Sandb. ; Loxopteria, Freeh). Devonian.

Family 16. Lunulicardiidae. Fischer.

Usually equivalve, triangular shells with terminal beaks, from which a sharp ridge
runs toward the lower margin, bounding a flattened area. Hinge margin straight, long.
Internal characters unknown. Silurian and Devonian.

Lunulicardium, Miinst. Anterior side with a byssal sinus. Silurian and
Devonian. L. semistriatum, Miinst.

Patrocardium, Fischer (Hemicardium, Barr. non Cuvier). Without byssal sinus.
Silurian.

Additional genera : Amita (Spanila, Tetinka), Mila, Tenka, Babinka (Matercula\
Barrande. Silurian.

Family 17. Ambonychiidae. Miller.

Shell Mytiliform, with no anterior wing, the anterior adductor obsolete; equivalve,
very inequilateral ; dentition obsolete or Schizodont ; ligament external, •multivincular (?) ;

368

MOLLUSCA

SUB-KINGDOM VI

byssus passing through a narrow gape between the valves which are otherwise closed. Ordo-
vician tfl^evonian.

The typical Ambonychia, according to Ulrich, is edentulous ; the forms ordinarily passing

under that name being now referred to Bysson-
.ychia. vln this group the byssus does not pass
through a notch in one of the valves.

The Ambonychiidae include the typical mem-
bers of Ambonychia, Byssopterla, and Amphi-
coelia, Hall ; Opisthoptera (Mega})tera), Meek ;
Anomalodonta, Miller ; Byssonychia and Allo-
nychia, Ulrich ; and their allies.

FIG. 619.

A, Byssonychia, sp. Cincinnati Group ; Cincin-
nati, Ohio. Interior of right valve. !/i (after
Miller). B, B. radiate (Hall), Ulrich. Same locality.

Clionychia, Ulrich.

Byssonychia, Ulrich (Fig. 619). Hinge
with several small cardinal and two or three
slender lateral teeth ; area striated ; otherwise
as in Ambonychia.

Paleocardia, Hall. Silurian. Mytilarca,
Plethomytilus, Hall. Devonian.

Gosseletia, Barrois (Cyrtodontopsis, Freeh).
Thicker shelled, with heavier and more
numerous teeth. Devonian.
Edentulous, concentrically sculptured. Silurian.

Family 18. Pinnidae. Meek.
Shell Mytiliform, not alate, dimyarian, the anterior adductor smaller; equivalve,

FIG. 620.

Pinna pyramidcdis, Miinst.
Quader Sandstein ; Schan-
clau. 1/3-

FIG. 621.

Pinnigena Secbachi, Bohm. Upper Jura ; Kelheim, Bavaria. External
and internal views, 1/3 natural size.

truncate, and wholly open behind; edentulous; area linear; ligament parivincular,

ORDER I

PRIONODESMACEA

369

ternalj shell structure coarse/// jiritumtic, with a tliin, jnirlit.il, nacreous lining; bynsifer-
ou*. Devonian to Recent.

Palaeopinna, Hall. Devonian ; North America.

Aviculopinna, Meek. A v.-ry >niall wing in front of the beaks. Carboniferous
and Permian.

Pinna, Linn. (Fig. 620). Shell thin, with a long hinge line ; valves carinatc,
triangular. Jura to Recent.

Pinnigena, Sauss. (Trichites, Plott), (Fig. 621). Muscular impression very large ;
prismatic layer extremely thick ; sculpture divaricate. Jura and Cretaceous.

Atrina, Gray. Shell with broad adductor scars ; short hinge line and entire
nacreous layer. Carboniferous to Recent.

Cyrtopinna, Miirch. Jura to Recent.

t Family 19. Conocardiidae. Neumayr.

Shell sub-trigonal, anteriorly truncate and gaping, the margins of the gape frequently
produced into a tube-like rostrum and sharply serrate below, the posterior end usually
alate, tJie wing divided internally by a longitudinal ridge ;
dimyarian, the anterior adductor scars smaller; equivalve
more or less gaping behind; Schizodont, with a single
anterior lateral, and an obscure or obsolete cardinal tubercle ;
area ill-defined, amphidetic; ligament external, parivincular ;
shell structure cancellate, or built up of hollow prisms resem-
bling those of Pinna, but not solid; valves thick, internally
marginate ; byssiferous (?) ; marine. Silurian to Carbon-
iferous. , Conocardium alaefvnne, Sow. Car-
boniferous Limestone : Tournay,

This group includes Conocardium, Bronn ; (Pleuro- Belgium. Vi-
rhynchus, Phill.), (Fig. 622) ; and Hh^ndocardium, Fischer.

It is extremely isolated, and comprises some fifty species. These remarkable shells have
been referred by most palaeontologists to the Cardiacea, with which they have no connection
whatever except analogy of form with a few aberrant Cardiidae.

Family 20. Pernidae. Zittel.

Shell sub-mytiliform, with a broad posterior wing; monomyarian, the anterior addtn-fm-
absent in the adult; inequivalve, teeth irregular or absent, with a serial mn.lHriiK-n.lnr
ligament ; byssiferous, with a moderate gape, or none. Permian to Recent.

FIG. 622.

Fio. 623.
A, Gervillia aviculoides, Sow. Oxfordian ; Dives, Calvados. ]:, <;. Uiuartt, Huvignier. Hinge.

This family differs from the Pteriidae chiefly by its multivincular ligament in the adult
state. It finds its maximum development in the Jura and Cretaceous.

Bakewellia, King. Small, obliquely elongated, alatr liehiud, three to four deii-
ticulations under the l>eaks. Permian.

VOL. I

2 B

370

MOLLUSCA

SUB-KINGDOM VI

Gervillia, Defr. (Fig. 623). Posterior wing obscure, hinge plate thick, beaks
terminal, pointed, with obscure dental ridges sub-parallel
to the long axis of the valve. Trias to Eocene.

Sub-genus Hoernesia, Laube (Fig. 624). With a strong
tooth under the beak and sub-taxodont denticulations on the
posterior cardinal border.

Odontoperna, Freeh. Quadrate with two to three
oblique dental folds below the beaks. Trias.

Perna, Brug. (Isognomon, Klein; Mulletia, Fisch)
Hoernesia socialis, Schloth. sp. /•,-,. on,\ £P .
Muschelkalk ; Wiirzburg, Bavaria. (*lg- 625). .Lquiyarve, sub - quadrate, with terminal

beaks, an anterior byssal notch, edentulous hinge, and
numerous ligamentary grooves. Trias to Recent.

FIG. 624.

Inoceramus Cripsi, Mant. Upper Cretace-
ous ; Gosau, Austria. 1/2 natural size.

FIG. 625.

Perna Soldanii, Desh. Oligocene ; Waldbockelheim, near
Kreuznach, Prussia. i/2.

Pernostrea, Munier-Chalmas. Jura.

Inoceramus, Sow. (Catillus, Brong. ; Haploscapha, Conr. ;
Neocatillus, Fisch.), (Fig. 626). Rounded with concentric sculp-
ture ; prominent, rather anterior beaks, and edentulous hinge
bearing numerous small ligamentary pits. Jura, and especially
the upper and middle Cretaceous.

FIG. 627.

Actinoceramus sulcafiis,
Park. Gault ; Perte du
Rhone, 1/1-

Sub-genera : Actinoceramus, Meek (Fig. 627), with radial sculp-
ture ; Tolviceramus, Stol. ; Anopaea, Eichw.

Crenatula, Lam. Thin-shelled, elongate, smooth. Jura (?),
Pliocene, and Recent.

Family 21. Pteriidae. Meek.1

Shell Aviculoid, bialate, monomyarian, inequivalve, with an alivincular ligament ; the
byssus issuing by a notch in the smaller valve ; the young dimyarian, the anterior adductor
disappearing with age. Silurian to Recent.

Pteria, Scopoli (Avicula, Brug.), (Fig. 628). Cardinal border in the young with
pseudocardinal and lateral teeth, becoming more or less obscure with growth ; shell
thin, oblique. Devonian to Recent.

1 Bittner, A., Lamellibranchiaten der Alpinen Trias (Abhandl. k. geol. Reichsanstalt, Bd.
XVIIL), 1895.

ORDER I

PRIONODESMACEA

371

Sub-genera: Actinoptcria, Liropteria, Vcrtuinnin, H.ill. Devonian. /'/.,••,////..<. M-C..V.
1 1, -\ nniaii an.l ( larboniferous. .' Hutotia, de Kon. Carboniferous. Oxytoma, Meek (Fig. 629).
Trias to Cretaceous. Melcayrina, Lam. Jura to Ren nt.

Limopteria, Hall (Monopteria, Mr«-k : Mii<i!in»il<>iitti, /'-//--/y/x/X
whig ivduced, posterior largp. ]>pv<>nian and
Pteroperna, Morris ami l.vi-pit. Middlp Jura.

Fia. 628.

I'ti r'ui /•iiiitnii",

Portl. sp. Rhae-
tic : Kiissen,

Tyrol.

Fio.

rt''i-'<'i (i>.<-,/ti,,i«t) cnttfitti, Sow. Great Oolite ;
Luc, Calvados.

Fio. 630.

Pmulomonotis echin"'". S«i\v.
brash (Oolite) ; Button,

('urii-

Pseudomonotis, Beyr. (Eumicrotis, Meek), (Fig. 630). Left valve flat, anterior wjng
not developed or minute. Devonian to Cretaceous.

Cassianella, Beyr. (Fig. 631). Left valve inflated with prominent incurved beak ;

Cassianella gryt
St. Cassian, Ty

FIG. 631.

Miinst. sp. Upper Tri

FIG. 032.

Monotis salinarin, Schlotli. sp. H. I
Alpenkalk (Norian) ; Berchtesgaden,
Bavaria. 2/3.

small as in Pteria, but more

the right flat or concave, without byss-il sinus;
numerous ; area amphidetic, wide. Trias.

Monutis, Bronn (Fig. 632). Efj[iiivHlvi', compressed, radially striate, with low, sub-

FlG. 633.

Halolriii (l><i<,,,.-ii") LomoMU, Wissm. Lower
Keuper (Norian) ; Wengen, South Tyrol.

Fia. 034.

Posidonomya Jiecheri, Bronu.
Culm Measures ; Herborn, Nassau.

Vi-

central beaks; anterior wing indistinct, rounded; posterior wing short, truncate or
oblique. Trias.

Halobia, Bronn (Daonella, Mojs.), (Fig. 633). Equivalve like Monotis, but the
anterior wing only represented by a smooth non-projecting area (Halobia), or both
wings absent (Daonella). Abundant in the Trias.

Posidonomya, Bronn (Ablacomya, Steinm.), (Fig. 634). Equivalve, thin, compressed,

372

MOLLUSCA

SUB-KINGDOM VI

concentrically waved ; hinge margin straight, edentulous ; valves not auriculate ; beaks
sub-central, not conspicuous. Silurian to Jurassic. Over fifty species are known ; very
profuse in the Jura-Trias, sometimes forming massive beds.

Malleus, Lam. ; Philobrya, Carpenter ; Hochstetteria, Velain. Decent.

FIG.

Aucella Mosquensis, Keys.
Jura ; Moscow, Russia.

Upper

Family 22. Myalinidae. Freeh.

Shell obliquely ovate, widened behind, sometimes with a small anterior ear ; beaks
anterior or terminal; hinge edentulous, straight; area amphidetic, longitudinally
grooved; ligament parivincular ? Adductor scars sub-equal; byssal notch distinct.
Silurian to Jura.

Myalina, de Kon. Shell thick, oblique, with deep adductor scars anteriorly under
the terminal beaks. Silurian and Devonian. ,

Hoplomytilus, Sandb. ; Myalinoptera, Freeh ; Ptychodesma, Mytilops, Modiella,
Hall. Devonian. Leiomyalina, Freeh ; Aphanaia,
Posidoniella, de Kon. ; Liebea, Waagen ; Atomodesmc^
Beyr. ; Anthracoptera, Salter. Carboniferous.

Pergamidea, Bitt. Thick-shelled, equivalve, inflated ;
anterior auricle distinct, sharply truncated ; hinge margin
notched below the beak. Trias of Asia Minor.
Mysidia, Bitt. Anterior ear reduced. Trias.
Aucella, Keys. (Fig. 635). Thin, inequi valve,
inflated, small, concentrically waved, sometimes with
radial striae. Left valve larger, arcuate, with very small
anterior ear ; right valve flatter and smaller. Area
short, striated, with a ligamental sulcus below the beak. Upper
Jura and Cretaceous ; distribution world wide.

Family 23. Vulsellidae. Adams.

Shell Ostreiform, not alate, monomyarian, edentulous, inequi-
valve, with an alivincular ligament ; byssus wanting ; otherwise
as in the Pteriidae. Tertiary to Kecent. A degraded type
which has become specialised through commensalism with
Sponges.

Vulsella, Lam. (Fig. 636). Shell vertically produced,
irregular, edentulous, with a triangular chondrophore for the
ligament. Eocene to Recent.

Vulsellina, de Rainc. Eocene. ? Chalmasia, Stol. Cretace-
ous. (? Ostreidae.)

Superfamily 4. OSTRACEA. Goldfuss.

Shell degenerate, sessile, inequivalve, generally edentulous,
wings obsolete; with a sub-nacreous or porjellanous inner and
prismatic outer layer ; epidermis inconspicuous ; area amphidetic,
ligament alivincular; foot and byssus absent; valves usually
close-fitting ; mantle lobes free, without siphons.

FIG.

Vulsella Caillaudi, Zitt.
Lower Eocene ; Minich,
Egypt. 2/3.

Family 24. Ostreidae. Lamarck.

Shell distorted by early adherence to other objects ; monomyarian, the anterior adductor
absent; edentulous, or with obscure Schizodont dentition; dimyarian when young ; the
foot obsolete or absent in the adult Carboniferous to Recent.

OHDKR I

PRIONODESMACEA

373

o.s-/ />.?«, Linn. (Fig. 637). Shell invgular, iiie<|iiival \v, ami with ti-nninal beaks,
with radial or foliaceous sculpture, usually discrepant <>n the two valves. Sum.-

FIG. 637.
Ostrea <li</UaUna, Dubois. Miocene; Vienna Basin.

species (0. virginica, 0. titan, 0. gigantea, etc.) attain a very large size. Carboniferous
to Recent.

Alectryonia, Fischer (Dendrostrea, Swains. ; Actinostreon, Bayle), (Fig. 638). Left
valve attached to roots or branches by clasping shelly processes ; both valves with

Fio. 638.

Alectr i/nniii ijri ijn riii, Sow.
sp. Oxfoniian ; Dives,
Calvados.

<!i-in>li<ii'it uri-i'ntii, Lam.
Lower Lias; 1't'oliren, near
Donaneaohingen, Baden.

tiniiilin'ii
Isle of Riigen.

White Chalk;

strong, often divaricate folds and undulate margins. Trias to Recent ; maximum in
Jura and Cretaceous.

Gryphaea, Lam. (Pycnodonta, Fisch. ; Gryphaeostrea, Conr.), (Figs. 639, 640). L«-t'i
valve strongly arched, with iucurvi-d Leak, sessile when young, later free; right valve
flat and opercular. Lias to Tertiary ; chiefly Mesoxoic.

Exogyra, Say (Amphidonta, Fischer ; Ceratostreon, Aetostreon, Rhynchostreon, Bayle),
(Figs. 641, 642). Resembling Gryphaea, but the valves more equal, hinge with an
obscure tooth, beaks of both valves more or less spiral, the pit for the ligament narrow.
Upper Jura and Cretaceous.

374

MOLLUSCA

SUB-KINGDOM VI

Terquemia, Tate (Carpentaria, Desl.) Shell with* a marginal ridge, sessile by the
right valve ; left valve flatter, free. Trias and Lias.

FIG. 641.
Exogyra columba, Lam. Greensand (Ceno-

manian); Regensburg, Bavaria.

FIG. 642.

Exogyra flctbellata, Golclf. sp. Cenomanian ; Saint Paul
Cloister, Egypt.

Family 25. Eligmidae. Gill.

Shell thick, sub-equivalve, free when adult, resembling Chalmasia in form, anteriorly
with an irregular pedal gape ; edentulous, monomyarian, with the adductor seated on the
free extremity of a myophore projecting from the umbonal cavity, otherwise like the
Ostreidae. Upper Jura.

Eligmus, Desl. If the characters of this genus have been correctly interpreted, it
can hardly be retained in the Ostreidae. Further investigation of the genus is
desirable.

Superfamily 5. NAIADACEA. Menke.

Shell of varied form, normally equivalve, inequilateral, and dimyarian ; rarely
alate ; shell substance nacreous and prismatic, ivith a conspicuous epidermis; area
obscure or amphidetic ; ligament parivincular, usually opisthodetic and external ; pallial
lobes usually free, except for an anal siphon, the pallial line simple ; foot normally long,
compressed, keeled ; bijssus obsolete ; young usually with a distinct nepionic stage ; station
usually fluviatile or lacustrine.

Family 26. Cardiniidae. Zittel.

Shell equivalve, closed, with feeble concentric sculpture or smooth ; dentition Schizo-
dont or obscure; ligament opisthodetic, external; dimyarian, adductor scars sub-equal,
pedal scars feeble or invisible ; station marine or brackish water. Devonian to Trias.

Amnigenia, Hall. Devonian (Catskill) of North America, and Rhenish Prussia.

Anthracosia, King (Fig. 643). Shell thin, oblong ; hinge with a blunt elongated
cardinal, and a feeble posterior lateral tooth upon a thickened hinge plate. Common
in the Coal Measures and estuarine Permian of Russia.

Anthracomya, Salter ; Nayadites, Dawsoii ; Asthenodonta, Whiteaves ; Carbonicola,
M'Coy. Coal Measures. Palaeomutela and Oligodon, Amalitzky. Brackish Permian
marls of Russia.

ORDER I

PRIONODESMACEA

Anoplophora (Sandb.), Koenen (Uniona, Pohlig), (V\^. Oil. Ki^ht \al\v\vith a
Limit thick ranlinal tooth filling into ;i socket in tin- opposite valvt-. Lt-l'l valve
hi-siilr the socket has a long posterior lateral tooth. Trias (L«-tt«-nkohl.- . A. donacina^
Sdi loth.; A. lettica, Qum-t.

Tn'uonodus, Saudi). (Fig. 645). Cardinal tooth strong, triangular, sometime-
divided, short, oblique, anterior; two elongate lat.-rals in tin- left valvi-, ;md one

Anoi>t»]ili<'i-'i li'tt'n-,1. QIH •!
Trias; |-'ri.-rl richsluill (after
Albert!).

FIG. 643.

A, Anthrncosla carbonaria, Golclf. sp.
Permian ; Xiederstaufenbach, near Kusel,
Rhenish Bavaria. B, A. Lott.nen, Ludw.
sp. Coal Measures ; Hannibalzeche, near
Bochuni, Westphalia (after Lndwig).

FiO. 645.

* Sinitllii rih i-i. Albert!.
Trias (Lettenkohle) ; Xiiiiincrn,
Wurtemberg. A, Hinge, from a
reverse impression of cast. /-',
Natural cast. Vi-

lateral in the right valve. Trias; especially common in the Lettenkohle dolomite
and the Raibl beds.

Heminajas, Neumayr. Trias. H. (Myophoria) fissidentatu, Wolirmann.

Pachycardia, Hauer. Oblong or trigonal, concentrically striate or smooth; beak>
nearly terminal, curved, adjacent, with a lunule ; anterior end inflated, blunt ;

FIG.
Cardinia hybrida, Sow. Lower Lias ; Ohrsleben, near Halberstadt, Saxony.

posterior compressed ; two strong divergent cardinal teeth in each valve, the anterior
on the right being weaker and nearly marginal ; each valve has also a long posterior
lateral tooth. Alpine Trias.

Cardinia, Agassiz (Thalassites, Quenst.), (Fig. 646). Oblong, thick, short anteriorly,
rounded. Cardinal teeth weak or obsolete, posterior lateral strong. Lower Lias, and
reported also from the Dogger.

? Nyassa, Hall. Devonian. ? Guerangeria (Davousti), Oehlert. Lower Devonian.

376

MOLLUSCA

SUB-KINGDOM VI

Family 27. Meg-alodontidae. Zittel.

Shells equivalve, sub-Mytiliform, closed, with feeble concentric sculpture or none ; di-
myarian, with amphidetic area, and external opisthodetic ligament, frequently supported
by nymphae ; cardinal teeth strong, usually two or three, with a posterior lateral, all
heavy and amorphous ; anterior adductor scars distinct, with a well-marked myophoric
ridge and pedal scar, the posterior adductor scars frequently bordered by an elevated crest.
Marine. Devonian to Cretaceous.

These shells, which are often very ponderous, sometimes bear a remarkable resemblance
to some recent American Uniones. The myophoric ridge is common to very distinct bivalves
of many unrelated groups. The true position of these forms cannot be regarded as positively
fixed as yet.

Megalodon, Sow. (Tauroceras, Ly codes, Schafh. ; Conchodon, Stopp.), (Figs. 647-

FIG. 647.

Mcijulodon (Eumegalodon) cmullatus, Goldf.
Cologne, Vi-

Devonian ; Paffrath, near

FIG. 048.

Megalodon .(Neomeyalodori)
triqueter, Wulfen sp. In-
ternal cast. Trias dolomite ;
Bleiberg, Carinthia.

649). Beaks prosogyrous ; hinge plate very broad and massive, without laterals ; the

FIG. 640.
Megalodon (Neomegalodori) Gilmlxli, Stoppani. Rhaetic ; Elbigenalp, Tyrol (after Giimbel).

two cardinal teeth separated by a deep socket; anterior adductor scar small, semilunar,

ORDER I

I'lMONoDKSMACKA 877

in front of the anterior cardinal ; posterior scar longer, le.-s di-tin<-t, .-ituated on an
elevated oi- thirkened radial ridge. The oldest Devonian >]•••. je- M. ,-</. •////•/////. (loldf.
has amorphous cardinals and a smooth rounded shell (Sumegolodon). The Tria-.-i<-
species sometimes attain a large >i/e, have a radial posterior ridge, smootli tct-th, ami
divided right posterior cardinal teeth (Neomtgalodon, dumb.; They are extraordinarily
abundant in the Dachstein, Limestone, and Haujitdolomite of tin- Northern Alps, and
are also plentiful in the Raibl and llhaetic beds of tin- Southern Alj».'

Pachyrisma, Morr. and Lye. (Pachymegalodon, Giimb.) Like Mi<in]i>ilni), but with a
larger anterior adductor scar, a rounded anterior tooth l.rtore the cardinals, and a
strong posterior lateral. Trias to Upper Jura.

Durga, Bohm. Like Pachyrisma, but without an elevated area at the po-terior
adductor. Lias.

Protodicerox, Bohm. Lias. Dicerocardium, Stoppani. Rhaetic.

Family 28. Unionidae. Fleming.

Shell equivalve, dimyarian, typically Schizodont, with pseudocardinals and laterals
ifili/itiferous; conspicuously nacreous; beaks usually sculptured ; ligament opisthodetic,
external; lobes of the mantle united to form an anal siphon, but the functional br(tn<-}iinl
siphon usually incomplete below ; foot compressed, keeled, large, rarely with a feeble byssus ;
usually dioecious ; the young having a distinct nepionic stage (glochidium). Flud-iHI-.
Trias to Recent.

Typical Uniones make their appearance in the Trias of Texas, but are not abundant until
the Cretaceous arid Tertiary. The origin of the family has been sought in the Trigoniidae,z
which have a very similar ontogeny as a group ; in Trigonodus* and related forms ; and by
Pohlig in the Triassic Uniona. An older view recognises the Carboniferous Anthracosia and
other Cardiniidae as probable ancestors. The weight of evidence is in favour of the latter,
though there is much probability that each of these groups bears a certain amount of relation-
ship to the present family, which will be better realised when more evidence is obtainable.

Unio, Retzius (Fig. 650). This, the typical genus, was founded on the pearl
mussel (Mya margaritifera, Linn.), in which the posterior laminae of the hinge are

Fir;.
Unio Stachci, Xeuinayr. Pliocene (Congerian stage); Sibinj, Slavonia. 7), Adductor; JT, Pedal MMI-.

obsolete. The majority of species, however, have amorphous, heavy, radial, pseudo-
cardinal and lateral teeth on the hinge; the shell is variable in form and ornamenta-
tion, some species having strongly marked sexual differences in the sludl. Most of
the species are pearly, with a conspicuous brown or greenish periostracum ; the
anterior adductor scars are high, and the pedal scars conspicuous.

1 Tausch, L. von, Ueber Conchodus, etc. (Abhandl. geol. Reichsanstalt, XVII.), 1892.

2 Neumayr, J/., Ueber die Herkunft <ler Unioniden (Sitzber. Wien. Akad. XCVIII.), 1889.

3 W&hrmann, S. von, Ueber die systematische Stellung der Trigonidem und die Abstannuunu' 'l'-i
Nayaden (Jahrb. geol. Reichsanst. Bd. XLIII.), 1893.

378 MOLLUSCA

SUB-KINGDOM VI

Anodonta, Cuv. Valves thin, and armature of the hinge obsolete ; lives in still,
muddy water. Tertiary and Kecent.

Family 29. Mutelidae. Gray.

Shell and anatomy resembling the Unionidae, without pseudocardinals and laterals ;
having, when dentiferous, an irregularly Taxodont hinge armature, generally partly
closed mantle lobes, a complete branchial septum, more complete siphons, and with a
nepionic stage represented by a Lasidium, resulting in unsculptured beaks for the adult
shell. Cretaceous to Eecent.

Spatha, Lea. Elongated, inequilateral, with a short edentulous hinge. Upper
Cretaceous of Provence, and Eecent in South Africa.

Leila, Gray ; Aplodon and Plagiodon, Spix ; Mycetopus, d'Orb. ; Mutela, Scopoli ;
and Iridina, Lain. Recent.

Family 30. Etheriidae. Lamarck.

Shell sessile, irregularly modified by adherence to other bodies, nacreous, with a
tendency to cellularity of structure; edentulous; ligament amphidetic, parivincular,
deeply sunken, with a large internal resilium, modified by the distortion of the valves ;
young regular, equivalve, dimyarian ; the adult irregular, inequivalve, and either (1)
monomyarian, or (2) with a very degenerate anterior adductor, or (3) with sub-equal
adductors. Mantle lobes united only for the anal siphon ; foot degenerate or absent in
the adult ; young byssiferous ; station fluviatile. Pleistocene and Recent.

The young shell of Sartlettia has well -marked nyraphae and internal resilium. The
relationship of the Naiades to Pteria renders the remarkable resemblance of the adult Mulleria
to Ostrea less surprising, since Ostrea is now known also to be derived from the Pteriidae.

Etheria, Lam. Ostreiform, attached to rocks in African rivers. Also Pleistocene
of West Africa.

Mulleria, Ferussac ; Bartlettia, Adams. Recent ; South American rivers.

Superfamily 6. TRIGONIACEA. Bronn.

Shell equivalve, inequilateral, closed, dimyarian, not alate ; shell substance nacreous
and prismatic ; hinge teeth few, sub-umbonal, typically Schizodont ; area obscure or none ;
ligament parivincular, opisthodetic, external ; gills filibranchiate ; mantle lobes usually
free, but modified on the posterior edges to form functional siphons without conjunctive
partitions; pallial line usually simple; non-byssiferous, though possessing an obsolete
byssal apparatus ; young without a distinct nepionic stage ; dioecious ; marine.

Family 31. Lyrodesmidae. Ulrich.

Shell with the hinge armature radiating fan-like from below the umbones ; teeth five
to nine ; pallial line feebly sinuate or simple. Silurian.

Lyrodesma, Conr. (? Actinodonta, Phil.) Shell oval, cardinal border narrow, without
ligamentary area. Silurian ; America and Europe.

Family 32. Trigoniidae. Lamarck.

Shell with few hinge teeth (§), the mantle lobes wholly free, but so applied to each other
in life as to form functional siphons ; pallial line simple. Devonian to Recent.

ORDER I

I'HIONODKSMACKA

879

(sVA /'-.<»/ a. -i. Kin- ••!•'!<,'. ';:»!. Ovate or quadrate, smooth ; lateral teeth not Muted:

anterior adductor seal1 with a .-mall radial l>utt iv.-.-. Abundant in the iVrmian.

Myophoria, Bronn (Neoschizod u *, (Jieb.), (Figs. o'."<^, «;."»:?.

Smooth or radially sculptured, Lr\ , u-ually with a .-tron^

i-adial ridp- extending IVoni the ^Rv ^^/ nnilioin-s Lack ward and

do\vnward to the hasal margin ; ^^f^^ ^ne ^''"'I't'iiv on th-

thus M-parat.-d usually di.-
• •ivpant.

Schizodus obscurus, Sow. Zechstfiu ;
rodenbach, near Hanuti. ^4, Cast,
Hinge, Vi (after King).

Alh. s]>. Schauinkalk ;
Riidersdorf, near
Berlin. 1/1-

Myophorio
Upper Trias; St. Cassian, Tyrol.
A, Exterior of right ralve, ' ,.
/.', Enlargdl view of hingf.

lateral teeth fluted, muscular scars buttressed by feeble ridges. Abundant in the Trias.
Sub-genus : Myophoriopsis, Wohrmaun.

Trigonia nm-is, Lam. Lower Brown Ji
dershofen, Alsace. 1/\.

r/««/«/". Park. Middl'1 CP-:
(Hervien); Meulo de Bracquegnies, Belgium. 1/1-

Trigonia, Brug. (Figs. 65.4-658). Surface sculptured with nodulo>e ril.- m- row.- ot

FIG. 650.

Trigonia costato, Sow.
Middle Jura; Wurtemberg.

FIG. 657.

7V/'/""/", cf. ulifoi-iiiis, Park. Senonian ;
Vaels, near Aix-la-Chapelle. i/!.

FKJ. 658.

Lam. Recent ; Aus-

tnilia. Hin-e, Vi-

pustules, the posterior dorsal area usually discrepant with the rest. Beaks opistho-

380

MOLLUSCA

SUB-KINGDOM VI

gyrous, nearly terminal ; teeth striated ; adductor scars strong, with buttressing ridges.
Lias to Recent ; abundant in Jura and Cretaceous, very sparse in later .horizons.

IV. ISODONTA. Fischer.

Superfamily 7. PECTINACEA. Reeve.

Shell usually inequivalve, flabelliform, more or less auriculate, and monomyarian ;
shell structure sub-nacreous, corrugated, and rarely prismaMc, occasionally tubular ; area,
when present, amphidetic ; ligament amphidetic, alivincular ; gills filibranchiate, free, the
filaments with or without a reflected limb ; mantle lobes free, without siphons, usually with
ocelli, papillae, or other tactile prominences along the margin, and with an inner pro-
jecting lamina (curtain] near the margin, at right angles to the plane of the valves ; pallial
line simple ; foot small, usually sub-cylindrical, grooved, and byssiferous ; usually mono-
ecious ; marine.

Family 33. Pectinidae. Lamarck.

Shell inequivalve, inequilateral, auriculate, usually closed, monomyarian, usually
free; area amphidetic or obscure; ligament obsolete externally, the immersed portion
forming an internal resilium, provinculum Taxodont in the
very young, obsolete later, the crural teeth feeble or not developed.
Silurian to Recent.

Aviculopecten, M'Coy (Fig. 659). Shell Pectiniform,
radially sculptured. Hinge margin long, feebly auriculate ;
ligament in numerous shallow grooves radiating to ' the
amphidetic margin of the area. Silurian to Carboniferous.

Sub-genera : Pterineopecten, Hall ; Orbipecten, Freeh (Lyrio-
pecten, Hall). Devonian.

Crenipecten, Hall (Pernopecten, Winch.) Like Aviculo-
pecten, but with a Taxodont hinge. Carboniferous.

The preceding genera lead up to the prototypes of Pteriidae as a radical for the present
family.

FIG. 659.

papyraceus, S

Coal Measures ; Werden, We
phalia.

Pecten, Miiller (Vola, Morch
nearly equilateral, very in-
equivalve, sub - symmetrical,
with well-developed, sub-equal
ears; one valve (usually the
right) more convex than the
other ; interior of the valves
not lirate ; hinge with a strong
medial internal resilium, on
each side of which interlock-
ing crural ridges and grooves
radiate in the adult ; byssal
notch inconspicuous. Cretace-
ous to Recent.

Janira, Schum. ; Neithea, Droult), (Fig. 660). Shell

FIG. 660.

Sow.

Pecten (Clilamys) snlrfextorius,
Goldf. Coral-Rag ; Nattheiia.

The above diagnosis Is of the

sub-genus Pecten s. s. In a wide pecten quinqmcostata,
sense all the species of Pecten are Cenomanian ; Rouen. 1/1-
free and auriculate, and without

internal lirae. They have been divided into an excessive number of sections according to
the superficial shell characters, but these rarely march with anatomical differences, arid

ORDER I

PRIONODESMACEA

881

cannot properly be regarded as of generic value. The most familiar of the groups tlm>
named an- as In Hows : —

Chlamys, Bolten (Pallium, Schum. ; Decadopccten, Riipp.), (Figs. 661, 6»i'J . Sln-11

Fi... (;.;•.«.

Pecten

Pliocene; Rhodes.

hinn.

i'n (< ', i ,n ptoHtctes) lens,
Sow. Mi.ldhs Jura; Balin,
near Cracow. 1/1-

Fie. 604.

/'. (Knt-li

oormttoc,

UppiT -I

henzollern. 1/1-

radially sculptured, nearly equivalve, with small, unequal ears, and deep byssal notch with
well-developed ctenolium. Trias to Recent.

Camptonectes, Ag. (Fig. 663). Shell small, thin, nearly smooth, with fine divergent
striation radiating from a median line. Jura to Recent.

Entolium, Meek (Fig. 664). Smooth, thin, with sub-equal ears diverging at a sharp angh-
above the beaks ; byssal notch obsolete. Carboniferous to Cretaceous.

Pseudamusium, Adams. Shell small, thin, glassy ; the posterior ear obsolete, byssal notch
distinct. Cretaceous to Recent. Syncyclonema, Meek is scarcely different.

Fin. 665.
Amusium cristatus, Bronn sp. Miocene ; Baden, near Vienna. 1/1-

Fi...

llin,iit,.«i>,j,,-t,i.-, I'liill. si..
Mi.l.ll.- Junt; Balin, near
Cracow. 1/1.

Amusium, Schum. (Fig. 665). Shell \\iili i-aJM-d r.-nlial ril>h-t> intiTii.-illy: i-xti-ni;ill\
smooth or delicately sculptured ; valves large, flatti*h, with sub-equal car> : l.y>sil notch
incouspicuoiLs or absent. Lias to Recent.

Sub-genus : Propcamusium, Greg. Small, thin, abyssal ; often with relatively conspicuous
sculpture, usually discrepant on the valves. Tertiary and Recent.

Hinnites, Defr. (Fig. 666). Shell free and Pectiiiiform wlu-n youn^, later ndln-ivni
to other objects and more or less distorted. Trias to Recent.

Pedum, Brug. Shell with an alivincular ligament in an open groove and aiva lik--
that of Spondylus in the adult ; the young like Chlamys. Recent ; sessile in corals.

Family 34. Spondylidae. Fleming.

Shell ineqiwvalve, nearly equilateral, closed, Pectiniform, obscurely auriculate, mono-
myarian; sessile; area amphidetic, much larger on the attached valve; ligament alivincular,
resilium more or less submerged; byssus obsolete; hinge with a Taxodont province !n m.

382

MOLLUSCA

SUB-KINGDOM VI

becoming obsolete in the adult and replaced by the typically Isodont development of the

crura; otherwise as in the Pectinidae. Trias to Recent.

Plicatula, Lam. (Harpax, Park), (Fig. 667).
Shell compressed, with coarse radial, often divari-
cate ribbing, a small area, and long shallow crenulate
crural teeth, diverging at a sharp angle. Trias to
Recent ; maximum in Jura and Cretaceous.

Spondylus, Linn. (Figs. 668, 669). Shell in-
flated, with radial, often spiny or foliaceous sculp-

Plicatnla pectinoides, Lam.
Lias ; Nancy, France.

Sj)ondylus tenuispina, Sandb.
Kreuznach, Prussia.

Oligocene ; Waldbockelheim, near

ture ; attached valve with a conspicuous area ; crural teeth heavy, short, smooth.
Jura to Recent ; maximum from the Tertiary onward.

? Pachypteria, de Kon. Carboniferous. P. nobilissima, de Kon.

Family 35. Dimyidae. Dall.

Shell inequivalve, irregular, closed, auricles not differentiated, Ostreiform, dimyarian,
sessile ; shell substance sub-nacreous and
fibrous ; area amphidetic, obscure ; liga-
ment obsolete, resilium alivincular, in-
ternal; hinge armature Taxodont, obsolete;
crural development feeble; gills fili-
branchiate, the inner direct filaments
wanting, the outer not reflected; foot
and byssus absent ; anterior adductor FIG- 670.

distinct, small; posterior duplex, larger. _ Dimya Deshuyesiana, Rouault. Eocene; Pyrenees.

Trias to Recent.

, .

Inner a'nd outer views of right valve, 3/2 (after Rouault).

Dimya, Rouault (Dimyodon, Mun. Chalm.), (Fig. 670). The recent form inhabits
deep water.

Family 36. Limidae. d'Orbigny.

Shell equivalve, auriculate, gaping, Pectiniform, monomyarian ; shell substance
fibrous, with minute tubules, not nacreous or prismatic ; hinge edentulous, or with traces
of Taxodont armature; area amphidetic, equal in both valves; ligament alivincular,
resilium sub-internal; gills Jilibranchiate, with direct and reflected limbs; foot small

ORDER I

il i<lit i J'n,- in,

PRIONODESMACEA

l>ll*Xlfi-r<lH>i, flu- Ill/Mil*

tli>

of the

Lima, Brug. Shell inflated, with ndia] .-••ulpimv : l.«-aks p.. int. -d, and -• -painted
liy a lozenge -shaped area; edentulous. CarlM.niferon- to Uecent ;
iiiaxiniuni in Mr-.i/oic (over 300
species).

Sub-genera: Lima s. s.
auct. non Gray), (Fig. 671). Shell with

strong radial rihs.

to, •

Bow.

Lower (iMlit.-;
Bayeux, Calvados.

Fio. 671.

/.'///" pectinoidts, Sow.
Lower Lias ; Balingen, Wur-
teniberg. l/l-

KM.. 874.

F fi7._, J.imnea. du i

Fl0-6'2' Goldf. Qrest

Lima (Plagiosjpma) gigantea, Sow. Lower Lias ; Oolite ; I^angrune,

Goppingen, Wurtemberg. 2/g. Nunnamly.

fPlagiostoma, Sow. (Fig. 672). Smooth ov finely striated.

Limatiila, Wood (Fig. 673). Medially ribbed, laterally smooth, valves not gaping.

i-'n.. 1,7:,.
Ctenostreon probosculea, Sow. Oxfonlian ; Dives, Calvados.

Limaea, Bronn (Fig. 674). Small, with Taxodont armatui'.- at the angles of tin-
hinge. Lias and Recent.

Ctenostreon, Eiclnv. (Fig. 675). Compressed, irregular, thick-shelled, with coarse
radial ribs. Upper Jura.

384 MOLLUSC A SUB-KINGDOM vi

Superfamily 8. ANOMIACEA. Herrmannsen.

Shell monomyarian, not alate ; edentulous or Isodont, usually sessile ; shell substance
nacreous, tubuliferous, with traces of a prismatic layer; area obscure, usually small,
amphidetic ; ligament obscure, with an alivincular internal resilium ; gills filibranchiate,
mantle lobes free ; foot small, grooved, digitiform ; dioecious ; marine.

Family 37. Anomiidae. Gray.

Shell variable, irregular and inequivalve when sessile, byssiferous when young; in
most genera the byssus becomes modified to a calcified or horny plug passing through a
foramen in the attached valve, and fastened to other objects, a condition which may be
permanent or transient ; area small, amphidetic ; ligament amphidetic, more or less
internal, supplemented by an internal resilium, for which the crura serve as chondrophores,
ali- or multivincular ; hinge usually edentulous, rarely rugose, with amorphous inter-
locking rugosities ; posterior adductor small, sub-central, in the sessile forms reinforced by
the pedo-byssal muscles, which are modified for service as adductors. ? Devonian. Jura
to Recent.

Anomia, Mull. Shell thin, sessile by the calcified byssus passing through a sinus
or perforation in the right valve, conforming to the subjacent surface ; the left valve

more convex, with four muscular scars on
a central area ; a chondrophore in the
lower valve. Jura to Recent.

? Limanomia, Bouch. Devonian.
Hypotrema, d'Orb. Jura and Cretaceous.
Placunanomia, Brod. Miocene to Recent.
Carolia, Cant. (Fig. 676). Shell
orbicular, compressed, radially striated ;
right valve with a byssal foramen nearly
closed in the adult ; resilium much as in
Anomia ; adductor scar single. Eocene ;
Egypt.

Sub-genus : Wakullina, Dall. Smooth ;
byssal foramen obsolete ; the resilium received
on diverging crura in the upper valve. Oligo-
cene ; Florida.

Placenta, Retzius (Placuna, Brug.;
Placunema, Stol. ; Pseudoplacuna, Mayer).
Shell free, orbicular, thin, very compressed ;
the resilium with long, unequal crura.
Tertiary and Recent,

Ephippium, Bolten. Like Placenta,
but the shell radially waved ; young with a small byssal perforation, which becomes
closed and obsolete in the adult. Tertiary and Recent.

Placunopsis, Morr. and Lye. Shell rounded, imperforate, free, or sessile. Jura,
Hemiplicatula, Desh. (Semiplicatula, Fisch.) ; Saintia, Rainc. Eocene. Paranomia,
Conrad. Ripley Group. Monia, Gray. Miocene ; California.

i
V. DYSODONTA. Neumayr (emend.)

Superfamily 9. MYTILACEA. Ferussac.

Shell anisomyarian, usually equivalve, not alate or notched for a byssus, edentulous
or Dysodont ; shell substance sub-nacreous, rarely more or less prismatic, with a conspicu-

FIG. (576.

Carolia placunoides, Cantr. Eocene; Wadi el Tih,
near Cairo, Egypt. Interior of both valves, 2/3.

olU'KK I

IMMONODESMACKA

385

out epidermis ; «>•>« amphidetic or obxcm, : //,/,»„/, ,,t /,<,,->',•>'„, -nl,,,-, i»>-»/.i//v opiathodetic
and external ; </>'//>• usually filibranchiatt ; innnfle lobes without ocelli, more or less free,

,/,,n i-nllif ir/'tlt tin i' mil xijihon complete mnl th< l,ru,irhi<il ///(•-,////,/</. .- fi,,,t

fiii-iii, i/ronri'tl, ////xs//"' /v,//.s- ; ,nn,in> riunx ; mostly TIKI li m.

Family 38. Modiolopsidae. Fi.-clicr emend.

Shell Modioliform, usually e.(/nimli-i, //••<•, thin, with sub-cij""! mlilnrti,/- scars;
ligament deep-seated ; hinge edentulous or Difmnloiif : sometimes byssiferous. Silurian to
Cretaceous.

The heavier forms show an obtuse ridge or two extending fnuu tin- l"-ak- t<>\\urd the basal
margin. The pedal scars are separate from and behind the anterior adduet«.r>. The
included here appear to be
the prototypes of the .!///-
fi/ii/<f, from which they
differ chiefly in those char-
acters that are common to
most of the ancient types,
such as the sub-equality of
the adductor scars and their
more dorsal situation. The
recent Idas is very similar.

Modiolopsis, Hall (Fig.
677). Valves elongate-
oval, closed, with nearly
terminal beaks, narrow
hinge plate, and edentul-
ous hinge. ? Ordovician ;
Silurian.

Modiomorpha,, Hall.
Similar, but with a wider
hinge plate, and single,
oblique, elongate, posterior
ridge - like tooth. De-
vonian. 0 • sp. OrdnVH.ian

clnnatl, Ohio. */!•

FIG.

Cin-

Fir;.

Mi/<M"iin-l,ii .-ti-lntntii, Goldf.
Oolite; Bayeux, Calvados, l/j.

Afyoconeka, Sow. (Fig.
678). Hinge usually with an elongate cardinal, and a long, weak, lateral t<«ith in tin-
right valve ; otherwise resembling Modiolopsis. Carboniferous
to Cretaceous.

? Hi/>/i»/i<x/i'iiiii, Sow. Thiek, inflated, ovate, concent rie-
ally waved. Hinge with a long, Muni, oMiijue, caitlinal
tooth, or edentulous ; adductor scare strong. Jura.

Modinluiinii, H'hiteavesia, Eurymya, Arisd'Hn, and Prolo-
bella, Ulrich; Goniophora, Phillips. Silurian and Devonian

Family 3!). Mytilidae. Fleming.

Shell equivalve, very inequilateral, hetero)ii;i<tri<n>, ,-lnjhtlij
<in /> in ;i, tif/iicnlly Dysodont : area amphidetic or none ; ligament
itxnufli/ external, deep-seated; rarely with an aliriin-nlnr
internal resilium ; pallial line simple; mantle lobes u/utnl

below the aim/ *ii>l«nt, otherwise free; qenerally byssiferous.
itytUut*uMaevt8,Bow. Great -p, ,,

Oolite; Minchinluimpton, Eng- Devonian to Kecent.

Mytilus, Linn. (Fig. 679). Shell elongated, thin, with

terminal pointed beaks ; valves wider and rounded behind, gaping a little for the
VOL. I 2 C

386

MOLLUSCA

SUB-KINGDOM VI

byssus, smooth or radially sculptured, witli smooth margins, conspicuous epidermis,
and a thin nacreous layer ; hinge with a few small teeth under the beaks, or edentulous.
Trias to Recent.

Pachymytilus, Zitt. (Fig. 680). Shell • thick, trigonal ; the front margin deeply
impressed. Upper Jura.

Modiola, Lam. (Figs. 681, 682). Like Mytilus, but the beaks not terminal, an-
teriorly rounded and wider. Devonian to Recent. •
Sub - genera : Modiolaria, Loven. Small, radially

n i '

Pachymytilus petasus, d'Orb.
Rag; Coulange-sur-Yonne. %.

FIG. 681.

Modiola aspera,
Sow. Great
Oolite; Lan-
Coral- grune, Cal-
vados, i/i.

FIG. 682.
Modiola inibricata,

FIG. 683.

Lithophagus inclusu?, Phill.
sp. Great Oolite ; Minchin-

of the

Sow. Middle Jura; Hampton, England. A, B,
Balin, near Cracow, Shell, i/j. C, Cast

sculptured toward the ends, usually smooth toward the middle, Modioliform. Tertiary and
Recent.

Crenella, Brown. Small, rounded, radially sculptured all over. Tertiary and Recent.

Stavelia, Gray. Recent, Valves spirally twisted.

Lithophagus, Meg. (Lithodomus, Guv.), (Fig. 683). Sub-cylindrical, with rounded
ends ; perforating coral limestones and other substances, in which the animal forms
flask-shaped excavations ; casts of the latter are often found in the fossil state. Car-
boniferous to Recent.

Family 40. Dreissensiidae. Gray.

Shell Mytiliform, equivalve, of prevailingly prismatic substance ; area linear, amphi-
detic ; ligament sub-internal ; anterior adductor and pedal protractors inserted on a
myophoric septum ; mantle lobes united to form ' anal and branchial siphons, and also
ventrally with a pedal opening ; pallial line usually simple ; gills reticulate ; otherwise
as in Mytilus. Tertiary to Recent.

Dreissensia, Van Ben. (Tichogonia, Rossm.), (Fig. 684). Smooth, without a pearly
layer, with a single apical septum ; fluviatile and estuarine. Eocene
to Recent ; Europe.

Mytilopsis, Conr. Mytiliform, small, thin ; Myophore for the
pedal protractor distinct from that which supports the anterior
adductor. Tertiary and Recent ; America.

Congeria, Partsch (Fig. 685). Sub - quadrate, heavy, large ; FIG. 684.

myophores as in Miiti

-n, *

Europe.

Dreissensiomya, Fuchs. Notable for being the only example of Mayence. Vi-
the Mytilacea with a distinct pallial sinus. Miocene ; Eastern Europe.

Septifer, Recluz. Valves with strong radial or divaricate sculpture. Marine.
Tertiary and Recent.

Very profuse in the Neocene of Eastern Dreissensia Bmnii,

Faujas. Miocene ;
Weiss e nan, near

ORDER n ANOMALODESMACEA

The recent families, Prasinii!<in MH\ ,V'»//V«/v /</•/-, it' tln-ir validity

Pra. 085.
Congeria subglolosn, I'artsch sp. Upper Miocene ; Inzersdorf, near Vienna.

may find a place in this vicinity. Prasina and Berthelinia are reported from tin-
Tertiary.

Order 2. ANOMALODESMACEA. Ball.

Superfamily 1. ANATINACEA. Dall.

Anomalodesmacea with V-shaped reticulate gills not secreting a, calcareous tube exterior
to the shell.

This group is divisible into sections as follows : — (a) Eusiphonia, with long siphons and
the lithodesma, when present, at the anterior end of the internal resilium, and external to
the mass of the resilium ; and (b) Adclosiphonia, with short siphons, the lithodesma dividing
the mass of the resilium mesially.

SECTION A. EUSIPHONIA.

Family 1. Pleuromyacidae. Zittel.

Shell slightly inequivalve, hinge with an obscure projection or edentulous, the card/ mi!
border of one valve covering that of the other valve, which is supplemented by a sort of
laminar nymph, the ligament sub -internal between
them; area inconstant or obscure; pallial sinus
present; valves closed or slightly gaping. Trias to
Lower Cretaceous.

Pleuromya, Ag. (Myacites, auct), (Figs. 686, 687).
Posterior side longer, somewhat gaping, hinge
margin with a thin horizontal lainin • in rai-h vahv,
the left interior, the margin with a li-rble notch
behind the lamina; ligament pai-ivim-nlar. Ti-ia-
to Lower Cretaceous; abundant, but si Hum well
preserved.

Gresslya, Ag. (Fig. 688). Like Pleuromya, but
the right hinge margin projecting over the left,
anterior side short, wide ; ligament parivincular,
almost internal, attached to an internal nyniph-

like callosity in the right valve, which appears as a groove on internal casts.
in the Jura, especially in the Lias.

<'li<>rostk<>\\. ' nt-ar MUM-IIW. .1, IntiTiial
cast, 1/1-

Alanidant

388

MOLLUSCA

SUB-KINGDOM VI

Ceromya, Ag. (Fig. 689).

Cordate, inflated, with, rather anterior, prosogyrous
beaks ; hinge margin of the right valve
superior, edentulous, but with a blunt

Pleuromya tenuistriata,
Ag. Middle Jura, Za-
jaczki, Poland, ifr.

Fio. CSS.

Gresslya latirostris,
Ag. Lower Oolite ;
Tannie, Sarthe. 1/1-

Ceromya, cf. Aalensis, Quenst. Middle Jura ; Kneut-
tingen, Lorraine. Hinge, 1/3.

elongated process in front of an internal callosity. Chiefly occurring as casts. Jura,

Family 2. Pholadellidae. Miller (emend.)

Shells obovate, usually attenuated behind and slightly gaping, hinge margin thin,
edentulous, ligament parivincular, external ; posterior adductor scar large. Palaeozoic.

Allorisma, King. Elongate, arcuate, the pallial line sinuated, anterior side
shorter, sometimes with a lunule ; sculpture strongest mesially. Carboniferous and
Permian.

Rhytimya, Ulrich. Elongate, sub-quadrate, concentrically waved, the waves
stronger anteriorly ; sculptured on the posterior half with
radiating series of granules ; lunule very narrow. Silurian.
Pholadella, Hall ; Cimitaria, Hall. Devonian.

Family 3. Pholadomyacidae. Gray.

Shell substance nacreous and cellule-crystalline; gills com-
pletely united behind, forming a septum below the anal

FIG. (590.
Pholadomya Murchisoni,

Sow. Middle Jura:
chnow, Poland, l/i-

Piez-

Fio. 691.

Pholadomya deltoidea, Ag.
Middle Jura ; England. 1/2-

FIG. 602.

Pholadomya Puschi, Goldf. Oligocene ;
Tb'lz, Bavaria. .

chamber; foot small, with an opisthopodium ; siphons long, united to their tips, not
ivholly retractile, naked ; ventral commissure of the mantle with a pedal and an opistho-

OUDKU II

ANOMALODESMACEA

889

podial foramen. Shell thin, equivalve, gaping, edentulous, or with an obscure sub-

umbonal tubercle; li<i<mn'nt, and resilium external, opisthodetic, seated on nyiui>!«» .

area obsolete or obscure, not amphidetic ; beaks entire; pallial sinus well »«<//•/.«/.
marine. Trias to Recent.

Pholadomya, Sow. (Figs. 690-692). Shell thin, .-iib-ovate, with radial an<l con-
crnlric sculpture, inflated, and with ratlin- pruniinenl beak> : hinge edentulous, or
with ah obscure thickening; scars feel.le, pallial >iniis moderately deep. In the

Fio. 693.

Gonimnya Duboisi, Ag. Inferior Oolite ; Bayeux,
Calvados. A, Shell, ift. B, Surface showing
punctations, magnified.

Fio. c.'.' t.

Homomya (Arcomya) calceiformis, Ag. Inferior
Oolite ; Les Moutieux, near Bayeux, CuvadOS. - ,.

posterior dorsal region the radial sculpture is usually feeble or absent. Lower Lias to
Recent ; formerly very abundant, but now represented by but a single species from
the Antilles.

Procardia, Meek. Includes those forms with an escutcheon. Jura.

Goniomya, Ag. (Fig. 693). With V-shaped sculpture. Lias to Cretaceous ; very
plentiful in Middle and Upper Jura.

Homomya, Ag. (Arcomya, Myopsis, Ag. p.p.), (Fig. 694). Distinguished from tin-
typical Pholadomyas by its smooth or very finely sculptured shell, without rib.-.
Trias to Cretaceous.

(?) Machomya, Plectomya, Loriol ; Mactromya^ Ag. Jura and Cretaceous.

Family 4. Anatinidae. DalL

Soft parts like Pholadomya, the foot small and grooved, ventral foramina small, and
the siphons with a horny integument, not entirely retractile. Shell sub-equivalve, tr\nn-<it<\
or gaping behind, edentulous, the resilium internal between
two spoon-like chondrophores vertically directed and often
supported by buttresses ; ligament obsolete or absent ; area
obsolete; beaks transversely fissured; pallial sinus well
marked ; monoecious ; marine. Jura to Recent.

Anatina, Lam. (Platymya, Cerconnja, Ag.; Plicomya, Flo 6y5

StoL), (Fig. 695). Shell thin, nearly equivalve, con- Anat:na pnilwt<tt 'Zittel. Upper
centrically but feebly sculptured, posterior side shorter Cretaceous ; Gosau Valley, Austria,
than the anterior. Jura to Recent.

Periplomya, Anatimya, Conrad ; Ehynchomya, Agassiz. Cretaceous.

Family 5. Periplomidae. Dall.

Shell sub-nacreous, conspicuously inequivalve, nearly closed, edentulous; the
internal, between two anteriorly or vertically^directed chondrophores, often buttressed, the
lithodesma rarely wanting; ligament and area absent; beaks fissured ; pallial sinus

390 MOLLUSCA SUB-KINGDOM vi

broad and shallow ; siphons separated to their bases, naked and wholly retractile ; mono-
ecious ; marine. Tertiary and Kecent.

Periploma, Sclium. Shell oval or rounded, smooth or with faint concentric striae ;
lithodesma present. Tertiary and Recent.

Cochlodesma, Couth. Buttress of the chondrophore posteriorly directed ; no litho-
desma. Pliocene and Recent.

Bontaea, Leach (Ligula, p.p. Mont.) ; Tyleria, Adams. Recent.

Family 6. Thraciidae. Dall.

Shell earthy and cellulo-crystalline, not nacreous ; inequivalve, thin, edentulous, often

with a granular surface ; ligament and resilium
chiefly external, opisthodetic, parivincular, seated
on posteriorly directed nymphae ; area absent,
beaks usually entire; valves nearly closed, with
pallial sinus; mantle openings small; siphons
long, separated to their tips, naked; monoecious;
marine. Jura to Recent.

Thracia, Leach (Corimya, Ag.), (Fig. 696).
Shell smooth or concentrically striated, with
granular surface, usually more or less rostrate.
Trias to Recent.

Fl0-696' Cyathodonta, Conr. Shell with oblique or

8- uPPer Juri ' Pruntrut' angular waves of sculpture, otherwise like the

preceding. Tertiary and Recent.
Bushia, Dall ; Asthenothaerus, Carpenter. Recent.

Family 7. Myochamidae. Dall.

Shell very ineqidvalve, free or sessile, solid, sub-nacreous, edentulous, the dorsal
margins of one valve overlapping those of the other, which jit into corresponding depres-
sions in the shell wall; ligament amphidetic, external or absent; resilium internal,
alivincular ; area amphidetic or obsolete, a false area formed on each side of the beaks by
the flattened cardinal margin of the valves ; shell closed ; pallial sinus small. Tertiary
and Recent.

The gills and siphons of Myochama, Stutchbury, which lives sessile on shells, are
more like those of Thracia than of the Pandoridae, with which it has usually been
associated. The anatomy of Myodora is unknown. Its minute area curiously recalls
that of Spondylus, and it is free.

SECTION B. ADELOSIPHONIA.

Family 8. Pandoridae. Gray.

Shell compressed, inequivalve, free, solid, with nacreous and prismatic layers; the
dorsal edges of the valves overlapping, but not socketed, ivith dentiform crural ridges on
either side of the resilium, but no true teeth; ligament amphidetic, external, obsolete;
resilium internal, opisthodetic, usually reinforced on its anterior surface by a mesial
elongate lithodesma ; area none ; valves closed, beaks entire, pallial line simple ; marine.
Cretaceous to Recent.

"' Pandora, Brug. Diverging crura without connecting lamellae ; buttress and
lithodesma absent. The sub-genus Kennerlia has a lithodesma. Tertiary and Recent.

ORDER ii ANOMALODESMACEA 391

Coelodon, Carp. Crura «>f tin- left valve united l>y a transver.-e lamella. r/ /,/,'„.
phora, Carp., lias tin- hin^e plate buttressed and a litli<»de.-ma. Tertiary and Recent.

Family 9. Lyonsiidae. DalL

Shell inequivalve, thin, sub-nacreous, edentulous; ligament obsolete, the resilium
internal, uniting the edges of a long, mesial lithodesma to a narrow chondrophoric sub-
marginal ridge on each valve; beaks entire, valves nearly closed, pallial sinus distinct;
marine. Tertiary and Recent.

Lyonsia, Turton. Small, thin, posteriorly elongate with delicate radiating sculp-
ture. Tertiary and Recent.

Entodesma, Phillippi. Recent. Actinomya, Mayer. Eoeene ; North America.

Family 10. Lyonsiellidae. Dall.

Shell nearly equivalve, sub-nacreous, with a more or less distinct tubercle in front of
the resilium on the dorsal margin; ligament obsolete, cartilage internal with a large
lithodesma; area obscure or absent; beaks entire; valves almost closed; pallial sinus
obsolete. Tertiary and Recent.

Halicardia, Dall ; Lyonsiella, Sars. Chiefly Recent.

Superfamily 2. ENSIPHONACEA. Dall.

Differing from Anatinacea by the formation of a calcareous tube, which may include
one or both of the valves, and is usually furnished with a perforated anterior
disk surrounded by a more or less complete fringe of small calcareous tubules.

Family 11. Clavagellidae. D'Obigny (emend.)

Shell degenerate, extremely specialised for a burrowing life; valves
nacreous, free when young ; when adult, one or both merged in a calcareous
tube anteriorly discoid and fringed, with a narrow pedal foramen in the
middle of the disk ; free valves edentulous, the ligament external, opisthodetic,
supported by nymphs ; pallial line sinuate ; tube frequently encrusted with
extraneous material ; marine. Cretaceous to Recent.

Clavagella, Lam. (Bryopa, Gray ; Stirpulina, Hoi.), (Fig. 697). One
of the valves not attached to the tube and adductor muscles persistent.
Cretaceous to Recent.

Brechites, Guett. (Aspergillum, Lam.) Both valves merged in the
tube,- anterior adductor reduced, and the posterior obsolete. Pliocene
and Recent. (.-,,,.

Superfamily 3. POROMYACEA. Dall. CMBM

Eocene ; Grig-

Anomalodesmacea having modified foliobranch or lamellar gills, slightly
or not at all reticulated, and frequently degenerate or even absent; valves
free, without a calcareous tube external to them ; mantle lobes united, with siphons and a
pedal, but no opisthopodial foramen ; the cartilage reinforced below by a lithodesma.

Family 12. Euciroidae. Dall.

Shell sub-equivalve, nacreous, and cellulo-crystalline, externally granulose; hinge
with a strong tubercle in the right valve before the resilium, and the dorsal margins
modified to overlie and underlie each other; ligament obsolete; resilium opisthodetic,

392

MOLLUSCA

SUB-KINGDOM VI

internal, with a strong lithodesma ventrally ; area obscure or absent ; a depressed false
lunule before the beaks; valves closed, pallial sinus shallow, obscure; siphons short,
separate; marine. Tertiary to Recent.

Pecchiolia, Menegli. Shell heavy; beaks spirogyrate, distant; sculpture radial.
'Eocene ; Alabama. Miocene ; Europe.
Euciroa, Dall. Eecent, abyssal.

The genera Verticordia, Wood.; Trigonulina, d'Orb. ; Haliris, Dall; and ? Allo-
pagus, Stol. (Hippagus, Desh. non Lea), are included under the family Verticordiidae.
Tertiary and Recent.

Family 14. Poromyacidae. Dall.

Shell rounded, nacreous, and ceUulo-crystalline, granular, or smooth externally ; hinge
with obscure tubercles in front of the resilium ; ligament external, opisthodetic ; resilium
sub-internal below the ligament, with a small lithodesma ; area obscure or absent ; a
depressed false lunule in front of the beaks ; valves nearly or entirely closed ; pallial
sinus small or obsolete ; marine. Cretaceous to Recent.

Liopistha, Meek (Cymella, Psilomya, Meek), (Fig. 698). Equi valve, oval, thin, in-
flated, concentrically or
radially striated, gaping
and compressed behind ;
beaks prominent, in-
curved ; hinge with a
nymph and projecting
process on each side ;
ligament sunken, partly
external. Cretaceous.

? Basterotia, Mayer
(Eucharis, Recluz non
Peron). Valves sub-equal, closed, with a strong tooth in the right and two in the
left ; surface granular ; form trapezoid. Miocene and Recent.

Poromya, Forbes (Embla, Loven). Ovate, plump, surface granular ; pallial line
irregularly widened, not sinuate. Eocene and Recent.

Dermatomya, Dall. Surface smooth, with a conspicuous periostracum ; pallial
line sinuate. Recent, abyssal.

Cetomya, Cetoconcha, Dall (Silenia, Smith). Recent, abyssal.

Liopistha frequens, Zitt.

FIG. 698.
Upper Cretaceous ; Gosau, Austria.

Family 15. Cuspidariidae. Dall.

Shell sub-equivalve, rostrate, earthy, or cellulo -crystalline, rarely with surface granula-
tions ; hinge edentulous or with sub-umbonal tubercula-
tion, sometimes buttressed ; ligament sub-internal, anterior
to the beaks or obsolete ; resilium internal, with a mesial
or ventral lithodesma ; area amphidetic or obscure ; valves
closed except at the tip of the rostrum; pallial line
simple; siphons united; marine. Jura to Recent.

Cuspidaria, Nardo (Neaera, Grav), (Fig. 699). Shell Fl0'

f- n j i • •;/ 11 . • i Citsmdaria eutpidata, Olivi. Mio-

concentrically sculptured ; hinge with a small posteriorly cene ;7 Baden, near Vienna. Vi-

inclined chondrophore in each valve, and an elongated
ridge behind it ; ligament always anterior to the beaks
Recent.

when present. Jura to

Sub-genera : Cardiomya, Adams ; with radial sculpture and a posterior lateral tooth in
the right valve. Leiomya, Adams ; smooth, with an anterior cardinal in each valve, and

ORDER in TELEODESMACEA

anterior and posterior laterals in the right valve only. Flcctwlun, Carp. ; surface granul:it«-«l.
Jihinoclama, D. and S. ; like Plectodon, lint \vithmit cardinal teeth. TV///////,, „///,/, D. and
S. ; hin^e with ;i buttress, one anterior canlinal, hut no lateral in either valve.
1 ). and S. ; right valve with a single cardinal, no other teeth in i-itln-r \al\i .
laminar buttress in each valve. Luzonia, Dall. Tertiary and Recent.

Myonera, Dall and Smith. Shell thin with concent ric waves and sparse radial
ribs; hinge edentulous ; rostrum short, rounded. Kecent, al>\>.-al.

ICorburella, Lycett. Middle Jura. >'/*//••/»/..//>•/>•, Saii«lbt-i^«-r. T«-rtiary.

Order 3. TELEODESMACEA. Dall.

A. PANTODONTA.
Laterals exceed im/ fn'n in any one group.

Family 1. Allodesmidae. Dall. (Cycloconchidae, Ulrich).

Shell rounded; valves equal, free, closed, with feeble concentric sculpture; area
linear, amphidetic ; ligament sub-external, parivincular, opisthodetic ; adductor scars
sub-equal, pedal scars above and distinct from the adductors ; pallial line entire ; hinge
with one or two lateral laminae on each side of the beak, the posterior below the ligament,
received into corresponding grooves on the right valve ; cardinal teeth radially grooved ;
one or two in each valve, those in the right valve stronger. Silurian.

This family, as suggested by Neumayr, probably exemplifies the first step in the develop-
ment of the Teleodesmacean hinge. But it must be admitted that its amphidetic though
linear area, the occasional multiplication to three of the lateral laminae, and the sub-ligament-
ary location of the hinder laminae, are very reminiscent of the prevalent Silurian Schizodont
type, and the family can be admitted to the Teleodesmacea only as a probable ancestor, rather
than a perfectly developed type of the modern assemblage.

Orthodontiscus, Meek (Gycloconcha, Miller ; ? Anodontopsis, M'Coy). Silurian ;
Ohio.

Allodesma, Ulrich. Like Orthodontiscus, but more elongate, the beaks more
anterior, the anterior adductor scar buttressed by a radial ridge, and the anterior
lateral teeth short or absent. Ordovician.

B. DlOGENODONTA.

Laterals normally one or two, and cardinals three or less, in any one groi'j>.

Superfamily 1. CYPRICARDIACEA. Dall.

Lobes of the mantle partly closed ventrally ; anterior lateral laminae absent, or
grouped with the cardinal teeth, short and obscure.

Family 2. Pleurophoridae. Dall.1

Shell substance cellulo-crystalline ; valves equal, free, closed ; adductor scars sub-equal,
free from the pedal scars; pallial line entire, or feebly sinuated ; area obscure; ////»/-
nient external or seated in a groove, parivincular ; margins of the valves usually plain ;
hinge with one left and two right posterior laminae, the anterior laminae absent or con-
fused with the cardinals ; two or three cardinal teeth in each valve, of which the posterior
in both valves is sub-parallel to the dorsal shell margin, and in the right valve is usually
bifid. Mantle with a moderate pedal and two siphonal openings, the latter usual I >i n»t
produced into tubes. Devonian to Recent.

1 Cyprinidae, p.p. of authors, but this name cannot be used.

394

MOLLUSCA

SUB-KINGDOM VI

This family, so well known under the preoccupied name Cyprinidac, probably shared the
same origin as the Astartidae, and the two do not definitely separate until the Jura. The
position of the Palaeozoic ancestors is necessarily doubtful, and they are placed differently
by different authors. The group may be conveniently divided into two sub-families : Pleuro-
phorinae and Veniellinac.

Pleurophorus, King (Fig. 700). Elongated, sub-rectangular ; beaks sub-terminal ;
surface smooth or with radial sculpture ; hinge with two cardinal teeth in each valve ;

FIG. 700.

Pleurophorus costatus, King. Permian ;
Byers Quarry, England. A, Shell, l/l
(after King). B, Internal cast from Gera,
Tlmringia (after Geinitz).

FIG. 701.

Anisocardia elegans, Mun. -Chalm. Kimmeridgian
Cap de la Heve, near Havre, i/i«

Devonian to

anterior adductor scars deep, with a buttress-like ridge behind it.
Trias ; especially abundant in the Permian.

Cypricardella,' Hall (Microdon, Hall) ; Mecynodon, Keferst. ; Cypricardinia, Hall.
Devonian. Astartella, Hall. Carboniferous.

Anisocardia, MuiL-Chalm. (Fig. 701). Rounded or trapezoid, plump, smooth or

radially striate ; posterior slope some-
times keeled ; hinge with a strong some-
times bifid right cardinal behind, and an
anteriorly directed front cardinal; left

FIG. 702.

Arcticn islandicn, Lin. Pleis-
tocene ; Bohuslan, Sweden.

FIG. 703.

Venilicardia conliformis,
d'Orb. Gault ; Seignelay,
Yonne.

FIG. 704.
Vcniello. tumida, Nyst. Crag ; Antwerp

valve with a forwardly directed anterior and a posterior cardinal tooth. Jura to
Tertiary.

Roudairia, Mun.-Chalm. Like Trapezium, but with a sharp keel and smooth area
behind, anteriorly with concentric ridges ; right posterior cardinal bifid. Upper
Cretaceous.

OKI.KK in TELEODESMACEA 395

Trapezium (Humph.), Megerle (Libitina, Schum. ; Cyprirdnlin, him. Sln-11
• •Imitate, trape/oidal, ( mi, -rut rically, or more rarely radially .-nilpt mvd, often with a
posterior keel; three cardinal Ict-ili in each valve, the posterior in tin- right valve
often bifid. Jura to Recent.

Plesiocyprina, Mun.-Chalm. Jura. Cicatrea, Stol. Cretaceous. Coralliophaya,
lilainv. Tertiary and Recent.

Arctica, Schum. (Cyprina, Lam.), (Fig. 702). Oval or rounded, inflated, concen-
trically striated; beaks prominent, curved, cardinals tin re in each valve, the left
posterior often bifid, the middle left cardinal largest, and the posterior ridge-like.
Abundant in the Jura and Cretaceous, and represented by one or two living
species.

Venilicardia, Stol. (Fig. 703). Cretaceous. Pygocardia, Miin.-Chalin. Tertiary.

Veniella, Stol. (Venilia, Morton; (?) Goniosoma, Conr.), (Fig. 704). Left valve
with the anterior cardinal strong, sub-triangular. Cretaceous and Tertiary.

Superfamily 2. ASTARTACEA. Ball.

Lobes of the mantle free ventrally ; lateral laminae obscure, when present distant
from the cardinals.

Family 3. Curtonotidae. Dall.

Shell short and heavy, with sub-terminal beaks ; valves free, equal, closed ; area
obscure ; ligament as in the Astartidae ; adductor scars, especially the anterior, deep ;
pallial line simple; hinge plate broad, without lateral laminae; the formula of the

cardinals I™- or J^010. Devonian and Carboniferous.

This group is inserted conformably with the opinion of Neumayr, who regards it as the
radical of the Astartidae.

Curtonotus, Salter. Oval, cardinal border thick, with one very strong tooth in the
left, and a strong anterior and thin posterior tooth in the right valve. Scars of the
adductors strong, especially the anterior. Devonian ; England.

Prosocoelus, Keferst. Devonian. Protoschizodus, de Kon. Carlxmiferous.

Family 4. Astartidae. D'Orbigny (emend.)

Shell substance cellulo-crystalline, with a pronounced epidermis; shell rounded or
sub-triangular, usually with concentric or not radial sculpture ; valves equal or sub-equal,
free, closed ; area distinct ; ligament and resilium external, parivincular, opisthodetic ;
beaks prosocoelous ; adductor scars sub-equal, with a distinct anterior pedal scar ; pallial
line simple; hinge plate distinct, hinge with anterior and posterior
lateral teeth and their respective sockets, usually more or less obsolete;
cardinal teeth not bifid at the summit, the terminal teeth frequently
obsolete. Lobes of the mantle free ventrally, not produced into siphons.
Trias to Recent. FIG 705

Astarte, Sow. (Crassina, Lam.), (Fig. 705). Roundly triangular Astarte Voitzi,
or oval, rather compressed, thick ; smooth or concentrically sculptured ;
lunule impressed ; right anterior cardinal strong. Alsace.

A number of genera have been associated with Astarte which probably belong elsewhere.
The following sub-genera, however, are worthy of recognition : — Coclastarte, Bohm ; Preconia,
Stol. ; Crassinella, Bayle non Guppy (Fig. 706) ; Prorokia, Bohm. Jura. Eriphyla, Gabb.
Cretaceous. Grotriania, Speyer ; Goodallia, Turton (Fig. 708) ; Hhectocyma, Dall ; Woodia,
Deshayes (Fig. 707). Tertiary and Recent.

396 MOLLUSCA SUB-KINGDOM vi

4

Opis, Defr. (Fig. 709). Trigonal, cordate, smooth, or concentrically striate ; beaks

Astarte (Goodallia)
miliaris, Defr. Eocene ;
Grignon, near Paris
(after Desbayes). ]

FIG. 706.

Astarte (Crassinellct) obliqua, Desh.
Inferior Oolite ; Bayeux, Calvados.

Woodia profunda, Desh.
Eocene ; Aizy, near Laon.
A, Hinge, enlarged. B,
Shell.

prominent, prosocoelous ; lunule very deep, bordered by a keel ; FIG. 709.

cardinal teeth long, narrow (2 : 1). Trias to Cretaceous. Opis Goidfussiana,

/-v • n -i T n T 7 • Tk-r d'Orb. Upper % Jura ;

Opisoma, fetol. Jura, keebachia, ISeumayr. Cretaceous. Nattheim.

Family 5. Crassatellitidae. Dall.

Shell as in the Astartidae, but the valves always somewhat unequal, and usually
more or less rostrate, the beaks compressed, erect, or opisthocoelous ; ligament internal,

FIG. 710.
Crassatellites plumbea, Chem. sp. Eocene (Calcaire Grossier) ; Damery, near Epernay. 2/3.

more or less obsolete, resilium large, wholly internal, attached at each end to a chondro-
phoric pit in the hinge plate behind the cardinal teeth ; lateral teeth and sockets usually
alternated in the valves, the hinge plate heavy, flat ; the posterior cardinal in the right
valve very small or obsolete, with no distinct socket in the opposite valve ; full cardinal

formula R1Q101- Lower Cretaceous to Recent.

The earlier forms of this family have a small resilium close to the nearly marginal liga-
ment. With time, later ones show a gradual descent of these organs, until in some of the

ORDER III

TELEODESMACEA

397

more specialised modern representatives there is no appreciable ligament remaining, and the
ivsiliuin has become large and deeply immersed. The parallelism between •
this ^roup and the Madridac, in the gradual immersion of the ligament,
could hardly be more complete.

Orassatelliies, Kruger (Crassatella, Lain., 1819, non Lam., 1799),
(Figs. 710, 711). Cretaceous to Recent ; represented by about seventy
fossil and forty living species.

Triodonta, Koenen. Oligocene. Scambula, Conrad : 1!> •unnuHn, ( !;il.li
(Stearnsia, White) ; Anthonyia, Gabb ; Crassatellina, Meek. Cretaceous.

? Ptychomya, Ag. Like Crassatellites, but with radial sculpture
and three cardinals in each valve. Cretaceous.

Crassinella, Guppy non Bayle (Gonllia, auct. non Adams ;
Pseuderiphyki, Fisch.) Small, sub-triantrular, very compressed, con-
centrically ribbed. Tertiary and Recent.

Oligocene; Wein-
1"' ne

Superfamily 3. CYRENACEA. Tryon.

Cypricardians which have become specialised for fresh or brackish water conditions,
and, as usual in such cases, have developed great variability of character.

Family 6. Oyrenidae. Gray.

Shell porcellanous, with a conspicuous epidermis, usually with concentric sculpture ;
valves equal, free, closed, usually with plain margins; area obscure or none; ligament
and resilium external, parivincular, opisthodetic ; adductor scars sub-equal, separate
from the pedal ; pallial line simple or with a small sinus ; hinge with anterior and
posterior laterals usually double in the right, single in the left valve, distinctly separated
from the cardinals; cardinal teeth bifid at the summit, three in each valve when none
are obsolete. Mantle open ventrally, the siphons distinctly developed, short, more or less
united. Lias to Recent.

Many of these forms merge with one another as we recede in time. The recent American
forms and many fossils show a pallial sinus ; oriental species are generally without it. In
some fossils the laterals of the right valve are not double.

Cyrena, Lam. Rounded, nib-equilateral, plump, concentrically sculptured, with
smooth margins; cardinals three, the laterals smooth. Lias to Recent (300 spt •«•!,- :

maximum in tin- -Cre-
taceous and onwards.

Sub-genera: Corbi<-uJ,i.
Megerle (Figs. 712, 713).
Smaller than Cyrena, and
the laterals sharply cross-
striated. Egeta, Adams.
Compressed, elongated,
thin ; almost rostrate.
Recent ; marine.

FIG. 712.

Corbicula fluminalis,
Mull. sp. Pleistocene ;
Teutschenthal, near
Halle, Saxony.

FH;. 713.

Corbicula semistriata, Desh. Oligocene (Cyrena
marls) ; Flonheim, near Alzey. !/!•

Batissa, Gray. Like
Cyrena, but the right
anterior and left posterior cardinals feeble or obsolete ; anterior laterals very short,
posterior ones elongated. Upper Cretaceous of Oregon, and living in Indo-Pacific
region.

Veloritina, Leptesthes, Meek. Laramie Group. Velorita, Gray. Recent. The
relations of the recent Galatea, Brug., and Fischeria, Bernard i, do not seem to be
positively fixed.

398

MOLLUSCA

SUB-KINGDOM VI

Family 7. Sphaeriidae. Dall.

Shell as in the Cyrenidae, but small, with a feeble, short ligament, a simple pallial
line, and no hinge plate ; cardinal teeth usually two in each valve, variable, very thin,
often nearly parallel to the hinge margin or defective in part of the series ; laterals as in
the Cyrenidae, distinct. Upper Cretaceous to Eeceiit.

Sphaerium, Scop. (Cyclas, Brug.) Branchial siphon complete ; shell inflated,
rounded. Upper Cretaceous to Recent.

Sub-genus Eupera, Bgt. Shell compressed, trapezoid. Tertiary and Recent ; sub-tropical.

Pisidium, Pfr. Shell inequilateral ; branchial siphon merged with the pedal
opening. Eocene to Recent.

Superfamily 4. CAEDITACEA. Menke.

This group appears to have branched off from the Astartoid radical in the early
Mesozoic, forming in one sense a sort of parallel series with the Astartidae, with which it
is contrasted most obviously by its prevailingly radial sculpture and prolonged posterior
cardinal tooth.

Family 8. Carditidae. Gill.

Shell as in the Astartidae, but usually with radial sculpture, the pedal adjacent to
the anterior adductor scar ; ligament external, parivincular ; resilium usually included
in the ligament, rarely internal; hinge fully developed, with the laminae as in the
Astartidae, and usually obsolete ; the anterior cardinal often obsolete, the posterior pro-
longed parallel with the dorsal margin even below the ligament. Full cardinal formula

Trias to Recent.

The earlier forms approach the Astartidae and Pleurophoridae so closely that they can
hardly be discriminated.

* Gardita, Brug. Elongate, quadrate, with prominent, very anterior beaks ; sculp-

FIG. 714.

Pulaeocardita crenata ,
Miinst. sp. Upper
Trias ; St. Cassian,
Tyrol.

FIG. 715.
Venericardia imbricata, Lam. Eocene ; Grignon, near

ture radial and usually imbricated, commonly with a lunule ; inner margins dentate :
cardinals long and oblifjue. Trias to Recent.

Palaeocardita, Conr. (Fig. 714). Like Cardita, but with a posterior lateral
tooth. Trias and Cretaceous.

Venericardia, Lam. (Fig. 7 1 5). Rounded or cordate ; lateral teeth absent or
obsolete. Cretaceous to Recent.

ORDER in TKLKODKSMACKA

Carditamera, Conr. Elongated, sub-mytilifonn. /'A /'/•«///< /•/'*, dun: Small,
tM|uilateral, trigonal. CalyptogtnCk^ Dall. Ovoid, .-mouth externally. i'nrilit>ll<i,
Smith. Small, with internal ligament. All Tertiary and Kn-.-nt. Tlfmlni, Adam- ;
Milneria, Dall. Females with a shelly marsnpimn. 1'cn-nt.

Superfamily 5. CHAMACEA. Geinitz.

Carditian forms specialised for a sessile habit, uxno/la n-<th exception a I hi
growth, and very unequal valves. Marine.

Family 9. Chamidae. Lamarrk.

Shell substance three-fold, the inner layers porcdlannu* and hilmlur, fl>> /////////.•
obscurely prismatic, the external cellulo-crystalline with reticulated tubules and an
spicuous epidermis ; valves unequal, irregular, one of them sessile ; closed, usually
rounded in form with conspicuous sculpture, often differing in the opposite valves; ad-
ductor scars sub-equal, elongate, pedal scars minute, distant; ligament and resilium
external in a deep groove, parivincular, opisthodetic ; area distinct, prosodetic ; beaks more
or less spiral, prosogyrous ; pallial line simple; hinge plate heavy, arcuate; hinge
frequently with a minute or obsolete posterior lamina, chiefly in the fixed valve ; cardinals
one or two in the free valve, two with an intermediate socket in the fixed valve ; the
anterior cardinal broad, usually deeply grooved or multifid, the posterior simple, long and
curved parallel with the dorsal border; siphonal orifices not produced into tubes; addm-tor*
each composed of two elements. Cretaceous to Eecent.

Either of the valves of Chama may be the sessile one, but the teeth in the fixed valve,
whether right or left, are always the same, and similarly with the free valve. The fixation
is generally by the left valve.

Chama, Lin. (Fig. 716). Nepionic shell rounded. Ligament sometimes continual
to the point of the beaks, as
in other bivalves with, gyrate
umbones ; form rounded,
attached valve deeper and
larger, the free valve natter ;
margins usually cross-
striated, surface lamellar or
spinose ; adductor scars large,
not elevated. Cretaceous to

r ic. 1 10.

fh,,Hu, M^BKWK, Lam. Eocene ; Hampshire. »/i-
Eocene.

Echinochama, Fiscli. Nepionic shell elongated, having tin- I'm-m, hinge, and other
characters of Cardita ; attached when adolescent, free in the young and adult st
Valves sub-equal and similar ; surface vermienlate, spinosi-, with radial ribs. Oligorene
and Recent.

Family 10. Diceratidae. Dall.1

Resembling Chama, but with the adductors usually borne on myophoric laminae, or
projections which are prolonged into the umbonal cavity below the hinge plate; rii.li->.-;

1 For the CJtamctcea and Rudistae, Neumayr proposed the term Pachydonta. For special liu-ru-
ture see: Ztttd, K. A. DOW, Die Bivalven der Gosaugebilde (Denkschr. Aka«l.-WisM-n>.-li. \Vit-n, B.l.
XXIV.), 1864.— Gemmetlaro, <J. G., Caprinellidae della Ciaca dei iutorni di 1'al.Tino, 1865.—
Mfnii'r-Chalmas, Prodrome d'une classification des Rudistes (Journ. de Couch yl. vol. XXL), 1873.—
White, C. A., Bull. U.S. Geol. Surv., No. 4, 1884 ; No. 22, ISSG.—DowilU, //., Bull. Soc. Gc-ol.
France [3], XIV. p. 389 ; XV. p. 756 ; XVI. p. 699 ; XVII. p. 627 ; XVIII. p. 324 ; XIX. p.
506 ; 1886-91. — di Stefano, G., Studii stratigrafici e paleontologici sul systema cretaceo di Sicilia.
I. Gli Strati con Caprotina. Palermo, 1888. — Duttrille, If., Etudes >ur U-s Kudistes (Mem. Soc. Gool.
France. Paleontologie, I.-IIL), 1890-93.

400

MOLLUSCA

SUB-KINGDOM VI

grotesquely distorted, sub-equal, with prolonged and twisted umbones, or the free valve is
reduced to an opercular form, spiral, and even concave; the teeth often reversed relatively
to their situation in Chama. Jura and Cretaceous.

Diceras, Lam. (Heterodiceras, Plesiodiceras, Mun.-Chalm. ; Pseudodiceras, Gemm.)
(Figs. 717, 718). Shell smooth, inequivalve, with both valves convex, the attached

B

FIG. 717.

Diceras arietinum, Lam. Coral - Rag ;
St. Mihiel, Meuse. 2/3.

A, Diceras arietinum, Lam. Coral-Rag ; St. Mihiel, Meuse.
Fixed left valve, 2/3. B, D. Zitteli, Mun.-Chalm. Tithonian ;
Stramberg. Right valve, ~/3. a, a', Anterior and posterior
adductor scars ; c, Major cardinal ; d, Socket for left anterior
cardinal ; ?, Ligamentary groove ; s, Buttress ridge before
posterior adductor scar.

valve larger, dentition normal or inverse ; beaks prominent, prosocoelous ; ligament as
in Chama, supported on nymphae ; right valve with a small anterior and large
elongated curved posterior tooth almost parallel with the hinge margin ; left valve

FIG. 719.

A, Requienia ammonia, Golclf. Urgonian ; Orgon, Vaucluse.
Lonsdalei, Sow. sp., from same locality. B, Left ; C, Right valve,

-B> C, Small individual of R. (Toucasia)

with a single large ear-shaped tooth in front of the elongated socket for the principal
tooth of the right valve ; posterior adductor scar on a projecting buttress. Upper Jura.

Apricardia, Gueranger. Cenomanian and Turonian.

Requienia, Matheron (Fig. 719, A). Smooth, very inequivalve, attached by the
spirally twisted beak of the left valve ; right valve opercular, spiral, flat ; teeth feeble ;
posterior adductor scar buttressed. Lower Cretaceous, especially the Urgonian of
Southern Europe, the Alps, and Texas.

Sub-genus Toucasia, Mun.-Chalm. (Fig. 719, B, 0). Differs from Requienia in having both
valves keeled. Urgonian and Cenomanian.

Matheronia, Mun.-Chalm. Urgonian and Cenomanian.

ORDER III

TELEODESMACEA

401

Family 11. Monopleuridae. Fischer.

Shell substance without canals ; shell • sessile, closed, very inequivalve ; free valve with
the cardinal formula 101, operculiform or slightly spiral; fixed valve ivith the formula.
010, conical, unrolled, or spiral ; area wanting ; ligament external, parivincular, opistho-
detic. Cretaceous.

Monopleura, Math. (?Dipilidia, Math.), (Figs. 720, 721). Very iiii-ijuivalvi-, .-month
or ribbed ; dentition always inverse ; attached by tin- right valve, which may be either

FIG. 720.

Monopleura trilolita, d'Orb. Neocomian (Sclirattenkalk) ; Orgon,
Vaucluse. 1/1- A, £, Anterior and posterior views. C, Interior of
attached valve.

Monopleura varians, Math. Ur-
gonian ; Orgon, Vaucluse. Interior
of both valves. Vi-

twisted or coniform; left valve conical or flat; ligament as in Chama ; posterior
adductor scar buttressed. Lower Cretaceous ; Southern Europe and Texas.

Valletia, Mun. - Chalin. Neocomian. Gyropleura, Douville. Cenomanian to
Senonian. Bayleia, Mun. -C halm. Turonian. B. Pouechi, Mun.-Chalm.

Family 12. Caprinidae. D'Orbigny.

Shell substance internally furnished with large parallel canals, the external layer
prismatic; valves heavy, irregular, unequal, closed; free valve spiral, cardinal for/mil"

FIG. 7-22.

Longitudinal section of
the, fixed valve of Caprina
<"/'•• rxii, showing cavities in
the inner shell layer.1

FIG. i

Cross -section
of the free valve
of Caprina com-
ni. n ni.", .showing
parallel canals
in the middle
layer.

FIG.

Plagioptychus Aguilloni, d'Orb. Upper Cretace-
ous ; Gosau, Austria. 2/3.

101, with a posterior myophoric crest for the adductor ; fixed valve conical or spiral,
cardinal formula 010 ; ligament in a deep groove, almost internal, parivincular, opistho-
detic. Cretaceous.

Caprina, d'Orb. (Gemmellaria, Mun.-Chalm.; Cornucaprina, Futt), (Figs. 722, 723).
VOL. I 2 D

402

MOLLUSCA

SUB-KINGDOM VI

Very inequivalve, attached by the apex of the coniform right valve. Left valve large,
spirally twisted ; inner layer of lower valve made up of concentric lamellae between

FIG. 725.

Plagioptynhus Aguilloni, d'Orb. (P. Coquandi, Math.) Upper Cretaceous (Hippurites Limestone); Le
Beausset, Var, France. A, Right. B, Left valve of the same individual, seen from within, 2/3. a, Anterior;
a', Posterior adductor scar ; I, Ligamentary groove ; c, Anterior tooth ; c', Posterior tooth of left valve ;
(I, Socket ; s, Buttress. C, Section of the small valve near the margin, showing canals (y) of the middle layer.
Magnified.

which cavities are sometimes left. The middle layer of the free valve traversed by
numerous simple, wide, parallel canals, extending from the margin to the apex ; tooth

of the attached valve well
developed, a series of depres-
sions between the posterior
adductor scar and the margin.
Cenomanian. The typical
species, 0. adversa, d'Orb., is
of large size.

Schiosia, Bohm. Like
Caprina, but the fixed valve

FIG. 726.

Caprinula Baylei, Gem in.
Upper Cretaceous ; Ad-
dauran, near Palermo. 1/-_>
(after Gemmellaro).

FIG. 727.

Caprinula Boissyi, d'Orb. Cross-
section of the lower (A) and upper
(B) valves, c, Teeth ; s, Septum ;
u, Body cavity ; x, Sockets. 2/3
(after Woodward).

FIG. 728.

Mass consisting of Crij>r»-
tina semist riata and C. striata,
d'Orb., and a smooth Sphaeru-
lites. Greensand ; Le Mans
(after d'Orbigny).

somewhat gyrate and the canal system present in both valves. Cenomanian ; Upper
Italy.

Plagioptychus, Math. (Sphaerucaprina, Gemm. ; Orthoptychus, Futt.), (Figs. 724,

OKI.KRIII TELEODESMACEA 403

725). Right valve conical or twisted, attached ; left valve convex, with incurved
beak ; ligament as in Chama. Shell structure like Caprina, but the free valve with
canals in the. middle layer; the walls of the canals hi furcate outward, form MIL: in
section a fringe of peripheral minor channels (Fig. 725, (7). Cenomanian and Turanian,

Caprinula, d'Orb. (Chaperia, Mun.-Chalm.), (Figs, 726, 727). Right valve elongated,
attached, conical, or incurved; left smaller, gyrate; both with canal system, the peri-
pheral canals smaller ; hinge as in Caprina. Cenomanian and Turonian, especially
in Portugal, Sicily, and Texas.

? Ichthyosarcolites, Desm. (Caprinella, d'Orb.) Cretaceous. Caprotina, d'()rl>.
728). Canals obsolete, replaced in some species by cavities. Neocomian to Turonian.

Coralliochama, White. Right valve conical, elongated, attached ; left smaller, with
incurved beak; anterior cardinal tooth buttressed, strong ; posterior cardinal weak:
canals as in Plagioptychus, bounded within by a coarsely cellular layer; lower valve
with a prismatic outer and laminar inner layer, separated by an intermediate cellular
stratum. Cretaceous; California.

Superfamily 6. RUDISTAE. Lamarck.

Chamacea in which the spirality of the valves has been lost, the area and ligament
vertically submerged, and the dorsal margins recurved over them so as to bring the ligament
into a sub-central position above the teeth but far below the dorsal margin, where it finally
becomes obsolete. The teeth, no longer forming a hinge but rather a clithrum, specially
modified for the vertical motion of the operculiform left valve, in which rotation is prevented
by the projection of the modified teeth into deep sockets in the fixed valve ; the latter conical,
thick; pallial line simple, enclosing the whole cavity ; shell structure specialised in two
very different layers ; sessile, marine.

The prisms of the outer shell layer are parallel to the long axis of the valve, and are cut
at right angles by numerous tabulae, which, together with the upper margin, often bear
impressions of radial vessels. The laminae of which the inner layer is composed are often
separated by cavities which recall the septa of Cyathophylloid corals, or those cavities found in
some oyster shells. In Hippurites the outer layer is traversed by a complex of canals. The
Eivdistae are the most peculiarly modified of all Pelecypods. Their relationship to the Chamidae
through Monopleura and Caprotina was first recognised by Quenstedt, and afterwards con-
firmed by Woodward, Bayle, Zittel, Munier-Chalmas, Douville, and others. Formerly the
group was referred to the most diverse connections, such as Brachiopods, Corals, Cirripede-s,
etc., or placed in a special class by itself.

The majority of Rudistids occur gregariously in large numbers, sometimes filling entire
beds ; they are often found in their natural position, standing vertically on the apex of the
attached valve. Notwithstanding their abundance, it is extremely difficult and often impos-
sible to separate the two valves and expose the interior, hence the hinge of many species is
still only imperfectly known.

Family 13. Badiolitidae. Gray (emend.)

Shell substance with the external layer thick, prismatic; the internal thin, cellulo-
crystalline (frequently destroyed in fossilisation) ; valves very unequal, the ligamentary
subsidence usually marked ; free valves with two projections and two somewhat irregular
myophores ; fixed valve with one myophore and two sockets ; summit of the valves sub-
marginal in the young, sub-central in the adult. Cretaceous.

Eadiolites (Lam.), Bayle (Biradiolites, d'Orb.), (Fig. 729). Lower valve conical,
erect, elongated, vertically ribbed, or made up of successive layers; usually with two
somewhat smooth bands extending from the apex to the upper margin, which are
supposed by Douville to indicate the position of siphonal orifices ; outer layer very
thick, composed of large polygonal cells or hollow prisms (Fig. 731). Upper valve
operculate, flat, or conical, with central or eccentric umbo. Clithrum formed l.y

404 MOLLUSCA SUB-KINGDOM vi

two vertically projecting striated processes (Fig. 729, c, c'), fitting into sockets near

a, b, Radiolites (Biradiolites) cornu-pastoris, d'Orb. Middle Cre-
taceous (Carentonian); Pyles, near Perigeux. a, Shell with closed
valves. B, C, The two more finely ribbed vertical bands, b, Interior
of larger valve, viewed from above, a, a', Adductor scars ; m, Pallial
line ; u, Space occupied by soft parts ; x, Empty space between the
sockets. 1/2 (after Bayle). c, Opercular valve of R. Bournonl, Desm.
sp. Upper Cretaceous (Dordonian) ; St. Mainetz, Dordogne. a, An-
terior ; a', Posterior myophore ; c, tf, Anterior and posterior processes
of clithrum. 1/3 (after Bayle).

FIG. 730.

Sphaerulites angeiodes, Lam. Upper
Cretaceous ; Gosau, Austria, a, Shell
with closed valves, i/j. b, Opercular
valve, i/i- A, Sinus of hinge, a, a',
Myophores ; c, c', Processes of clithrum.

the outer wall of the fixed valve ; next to and outside of the sockets are two large
unequal slightly excavated adductor scars,
corresponding to two broad myophores in the
upper valve. Middle and Upper Cretaceous ;
Europe and Texas.

Sub-genera : Lapeirousia, Bayle. The smooth
bands correspond internally to two prominent
tubercles. Synodontites, Pirona. Has the two
teeth of the upper valve fused.

Sphaerulites,
Delam. (Radiolites,
Birostrites, Lam. ;
Jodamia, Defr. ;
Dipilidia, ? Agria,
Math.), (Figs. 730-
732). Externally
like Radiolites, but
without the two

FIG.

banrh • val VP«? witli Portion of the outer shell layer
bands , A aives witn of the lower valye of & SphtJ>ru_

a re-entrant sinus lites or Radiolites showing the
s hollow prisms. Cretace-
Monte Gargano, Italy. i/x.

Sphaernlitcs foliaceus, Lam. Carentonian ; He
d'Aix, Charente. A, Sinus of the hinge, a, a',
Anterior and posterior adductor scars ; d, d', An-
terior and posterior grooved sockets for the pro-
cesses of the upper valve ; x, x', Empty spaces of
the ligament pits ; y, Cavity at the inner. end of
the sinus. 2/3 (after Goldfuss).

between the teeth,
which fit into sepa-
rate pits (d, d'\ usually joined by a ridge with the inner margin of the sinus ; the two

ORDER III

TELEODESMACEA

405

depressions (Fig. 732, x, x) next tin- sinus \\viv shown l>y IVtlx. to ha\v lieen.the seat
of a ligmentary connection between the valves; the adductor scars (a, a') ivsi ml,].-
those of Radiolites. Widely distributed in tin- Middle and Upper Cretaceous.

The supposed genera IHpilidia, Birostrites, and Jodamia are based on internal.
casts of Radiolites. The visible submersion of tin- ligament in some Radiolites enable.-
us to understand how the stages shown by Hippurites have arisen.

Family 14. Hippuritidae. Gray.

Shell substance of two layers, the external porous, grooved, and punctate ; the inner
lacunary and prismatic; exterior with sutures corresponding to an "anal" and
" branchial " inflection, and sometimes with a ligamentary suture ; clithrum formed of
two processes in the free valve, the adductors attached to myophores ; fixed valve with one
thin laminar process ; the adductor scars excavated, the anterior adductor duplex, forming
distinct scars. Cretaceous.

Hippurites, Lam. (Figs. 733-737). Lower valve cyliudro-conic, sometimes a metre
in length, attached by the apex, smooth or longitudinally ribbed, with three furrows

Fio. 733.

Hijifii rites Gosaviensis,
Douv. Upper Cretace-
ous ; Gosau Valley,

Austria. V-j.

FIG. 734.

Hippurites Oppeli, Douville. Nefgraben, near Russ-
bach, Salzburg. A, B, 0, Impressed lines bounding
convex vertical areas (columns) corresponding to the
region of the hin^e. i/2.

FIG. 735.

H 1/11111 rites organimns,
Montf. Vertical section
of a valve below the
living chamber, show-
ing the septa ami int'T-
septal cavities of the
middle layer, l/i-

bounding two " columns," or columnar areas, extending from the apex to the upper
margin (A, B, C). Upper valve depressed, conic, with sub-central umbo, usually with
two round or oval foramina ; outer surface showing pores, the apertures of short canals
which join larger canals radiating from the beak. The thick outer layer of the lower
valve is usually brown-coloured and made up of thin horizontal strata, which are in
turn composed of small vertical prisms. The white inner layer is porcellanous, and
sometimes contains vacant spaces in the lower part of the shell. Three prominent
folds are present, on the inner side of the shell, formed by the intending of lx>th
layers of shell, and corresponding to the external grooves (A, B, C). Of these the

406

MOLLUSCA

SUB-KINGDOM VI

anterior (A) is longer and thinner than the others, which are thickened at the internal
end and carry a small tubercle above. In the two sub-genera, d1 Orbignyia, Woodward

FJG. 736.

Hippurites radiosus, Desin. Upper Cretaceous (Dordonian) ; Royan, Charente. «, Upper valve (A, Sinus of
the hinge ; J5, C, Grooves corresponding to anterior and posterior columns of the lower valve ; c, Anterior, and
c', c", Posterior processes of the clithrum). l>, Interior of lower valve seen from above (A, Sinus ; 73, C, Posi-
tion of anterior and posterior columns ; a, a', Adductor scars ; d, Socket of anterior, and <?.', d", of posterior
processes of clithrum ; «, Body chamber of shell ; x, Vacant cavity near the sinus). 2/3 (after Bayle).

(H. biloculus, Lam,), and Batolites, Montfort (H. organisans, Lap.), the anterior sinus
disappears entirely. In Pironaia, Menegh., a number of accessory folds appear behind
the two columns. According to Douville, the two posterior
columns are homologous with the smooth bands of Eadio-
lites, and indicate the position of the siphons. Woodward
supposes that the pit (x) contained the internal ligament ;
but so far, remains of the ligament have only been found
in the bottom of the outer anterior sulcus, where it seemed
to form a vertical band. The second adductor scar is
small, and located between the sulcus and the anterior
column (5). The clithrum of the upper valve is extremely
difficult to prepare, and is known in only, a few species.
The anterior process shows near its base two tubercles
(a, a'), which correspond to the divided adductor scar of
FIG. 737. the lower valve. Behind the anterior there are two supple-

Hippuritescornu-vaccinum,Goidf. mental processes, which are received into the sockets d' and

VePSa?tSn; fhr^gh "both d" of ^ lower valve- The sPecies are verJ abundant in
valves showing the interlocking the Middle and Upper Cretaceous, and occur chiefly in

clithrum and relation of the shell- *,•,, -, -, ni » ., m, , -, , I.,.

layers. V2. littoral shallow water deposits. The most noted localities

are the Alps and Pyrenees, Provence, Charente, Istria,
Dalmatia, Greece, Sicily, Asia Minor, Persia, and Algiers.

Barrettia, Woodward. Cretaceous ; Jamaica and Guatemala.

Superfamily 7. LUCINACEA. Anton (emend.)

Shell with the anterior adductor scar narrower, produced ventrally ; posterior scar
shorter, rounded ; pallial line simple ; foot elongate, sub-clavate ; hinge feeble, teeth radial,
often obsolete.

<>KI>KK III

TELEODESMACEA

407

_

TanentHa

""/") <""> •""<««, Zitt.
nd Qoi& Coral-
Rag ; Glos, Calvados.

Family 15. Tancrediidae. Fischer.

Shell Donaciform, equivalve, icith an external ligament; the margin of the valves
entire; hinge with posterior
mnl <uiterior laterals, the latter
inconstant ; cardinals one in
flu- left or two in the right
valve, or two in each valve.
Trias and Cretaceous, ? Recent.

Tancredia, Lycett (Hettiut-

gia, Terq. ; Palaeomya, Zitt. VTO /^r^j

and Goub), (Figs. 737, 738). -1
Shell sub- arcuate, attenuated

lipfnrp flip Vipal-e wirlpr nnrl

beaks, WICt y,-, „,,,/,„ ,rr((ri/on»m, Dunker sp. Lower

shorter behind them ; obliquely Lias ; Hettingen, Lorraine. 1/1 (after Terquem).
truncate and somewhat gaping

posteriorly ; a cardinal tooth on each side, and also an elongated posterior lateral.
Trias to Cretaceous ; maximum in Lias.

? Meekia, Gabb. Cretaceous ; California. ? Hemidonax, Morch (Donacicardium,
Vest). Recent.

Family 16. Unicardiidae. Fischer.

Shell cordiform, equivalve, closed, concentrically striated; adductor scars elliptical,
the anterior longer ; pallial line simple ; margin of
the valve smooth ; ligament external, parivincular, seated
in a groove; with a grooved hinge plate bearing a single
obsolete cardinal in each valve, or none. Carboniferous to
Cretaceous.

Unicardium, d'Orb. (Fig. 740). Rounded, inflated,
with incurved beaks ; hinge margin thin, with a weak
cardinal tooth; ligament deep-seated. Trias to Cre-
taceous.

Scaldia, Ryckholt. Carboniferous.

Pseudedmondia, Fischer. Ligament completely external.

FIG. 740.
Unicardium excentricum, d'Orb.

Kimmeridgian ; Cap de la Heve, ~ , .f
npnr Havre, i/,. Carbonitei'OTis.

Family 17. Lucinidae. Fleming.

Shell substance porcellanous or chalky, usually with inconspicuous or dehiscent
epidermis, rounded, variably sculptured ; valves equal, free, closed, with low, prosocoelous
beaks; adductor and pedal scars adjacent or distinct, the latter small; anterior adductor
elongated, largely within the pallial line, which is not sinuate ; area within the pallial line
often granular or punctate ; cardinal area small, often deeply impressed ; ligament and
resilium sub-internal, set in a deep groove, but usually more or less visible externally ;
hinge plate distinct ; lateral laminae distant from the cardinals, anterior and posterior
in the right, with corresponding sockets in the left valve ; cardinal teeth radial, formula

^Y^, the posterior tooth larger and often bifid, but any or all of the teeth may be obsolete
or absent. Silurian to Recent.

Paracyclas, Hall. Rounded, thin-shelled, concentrically striated ; no lunule ;
hinge unknown. Devonian.

408 MOLLUSCA SUB-KINGDOM vi

Lucina, Brug. (Figs. 741-744). Rounded, convex, or lenticular, usually with a

FIG. 741.
Lucina (Miltha) gigantea, Desh. Eocene (Calcaire Grossier) ; Grignon, near Paris. 2/3.

lunule ; with delicate, concentric, or more rarely radial sculpture ; dentition usually

FIG. 742.

Liunna pulchra, Zitt. and Goub. Coral-Rag ;
Glos, Calvados. 2/j.

Lucina (Prolucina) prisca, His. Silurian ; Gottland.
Internal cast (after Roeiner).

normal, the laterals developed. Represented by upwards of 300 fossil and 100 recent
species. ? Silurian, Trias to Recent.

Sub-genera: Lucina s.s., Lam. 1799 (Loripes, auct.) Shell smooth. Adult with the

teeth and posterior radial plication of the valves obsolete.
Tertiary and Recent.

Prolucina, Ball (Fig. 743). Compressed, arcuate,
almost rostrate ; the anterior side larger. Silurian.

Myrtea, Turton (Fig. 744). Rounded, sub -equi-
lateral ; teeth and posterior fold present. Tertiary and
Recent.

Codakia, Scopoli. Compressed, reticulately sculp-
tured. Tertiary and Recent.

Miltha, Adams. (Fig. 741). Compressed, nearly
smooth ; laterals absent, cardinals long, feeble (3. 2).
Tertiary and Recent.

Divaricella, Martens. Rounded, inflated, valves ornamented with angular divergent
grooving. Tertiary and Recent.

Lucina {Myrtea) columbella, Lam. Mio-
cene ; Steinabrann, near Vienna.

ORDER III

TELEODESMACEA

409

Family 18. Corbidae. Da 11.

Shell differing from the Lucinidae in being transversely ova/, thick, with a heavy
hinge plate, and usually well-developed laterals; two or three strong cardinals in each*
valve ; the margin of the valves denticulate, and the exterior ttrongly tculptwtd : ligament
external, the adductor scars oval, mnl ///// ///•o/rr////,/ ,'„(,, tl,, j,,illi,il area. Tria.- t»
Recent.

This family is an offshoot of the Lucinidae, with which it is commonly united.

FIG. 745.
i, Iltiuer. Upper Trias; Sarize am Predil,

IT Raibl, Tyrol,

Gonodon, Scliafh. (Gorbis, p. p. auct.), (Fig. 745). Rounded, plump, concentrically

striated. Cardinals

L101

Trias and Jura.

~r— - , sometimes a weak posterior lateral present.

Corbis, Guv. (Fimbria, Megerle non Boh.), (Fig. 746). Thick -shelled, oval, inflated,

reticulately sculptured ; each valve with two short
cardinals, and anterior and posterior latnal> :
adductor scars similar, sub-equal. Jura to Recent.
Sphaera, Sow. (Palaeocorbis, Conr.) Lower
Cretaceous. Sphaeriola, Stol. Trias to Cretaceous.
Fimbriella, Stol. Chalk of Britain. Corbicella,
Mor. and Lye. Jura.

Corbis lamellosa, Lain. Eocene (Calcaire
Grossier); Grignon, near Paris. Vi-

FIG. 747.
Mutiella coarctata, Zitt. Turonian ; Gosau, Austria. 1/1-

Mutiella, Stol. (Fig. 747). Anterior cardinal border corrugated, upturned ;
posterior rectilinear, horizontal, with a feeble lateral tooth. Upper Cretaceous.

Kamily 19. Diplodontidae. Dall.

Shell sub-circular in outline, rarely nestling and irregular ; hinge with the laterals
obscure or absent, and the valve margins plain ; the adductor scars continuous peripher-
ally with thepallial line; soft parts like the Lucinidae, but with the external limb of the
gills developed, and the anal foramen not tubular. ? Jura, Cretaceous to Recent.

410

MOLLUSCA

SUB-KINGDOM VI

Diplodonta, Bronn (Fig. 748). Thin-shelled, orbicular, convex, concentrically
striate or pustulose ; cardinals 2. 2, the left anterior and right posterior bifid ; laterals

obscure or absent. Tertiary and Recent.

Ungulina, Daudin. Nestling and often
irregular. Felania, Recluz. Shell compressed ;
feeble laterals present. Axinopsis, Sars ; Sphae-
rella, Tenea, Conrad. Cretaceous to Eecent.

FIG. T48.
Diplodonta dilutata, Phill.

Family 20. Cyrenellidae. Fischer.

Pliocene ;

Rhodes. 1/1- Shell as in Diplodonta, but with a con-

spicuous epidermis; pallial area smooth; pailial

line not sinuate; hinge without lateral laminae; the cardinals like Diplodonta,
or with two cardinals in each valve soldered to each other dorsally ; cardinal formula

= , the anterior left cardinal usually obsolete. Pliocene to Recent, in fresh or

brackish water.

Cyrenoidea, Joannis (Gyrenella, Desh.) Pliocene of Florida, Recent in the Antilles
and West Africa.

Joannisiella, Dall. Hinge as in Diplodonta, resilium immersed, the larger cardinal

bifid, the teeth not soldered above. Cardinal formula ^ . Recent ; Philippines.

Family 21. Cryptodontidae. Dall.

Shell substance earthy, with inconspicuous epidermis and
equal, free, closed, with plain margins, smooth, or with feeble
concentric striae, and usually with a radial posterior flexure ;
adductors Lucinoid, pallial area often punctate ; ligament and
resilium parivincular, opisthodetic, sub-external, seated in a
groove ; area impressed ; hinge feeble without lateral laminae,
edentulous, or with an obsolete cardinal tooth in the right valve.
Cretaceous to Recent.

Cryptodon, Turton (? Axinus, Sow. ; Conchocele, Gabb),
(Fig. 749). Smooth, thin -shelled, living in deep water.
Cretaceous to Recent.

Philis, Fisch. Lunule deeply indented, projecting spoon-
like into the cavity of the valves. Recent.

ous beaks; valvt

n

A, Cryptodon sinuosus, Don.
Miocene ; Grund, near Vienna.
Vl- B, C. imicarinatits, Nyst.
Oligocene (Septaria - clay) ;
FreiemvaMe, near Berlin.

Superfamily 8. LEPTONACEA. Dall.

The incurrent and excurrent openings between the mantle lobes at opposite ends of the
body, the former anterior.

This group contains a great many commensal, nestling, or parasitic forms ; if indepen-
dent usually very active, crawling like Gastropods on a sub-reptary foot, and with the mantle
edges more or less reflected over the valves.

Family 22. Leptonidae. Dall.

Shell cellulo-crystalline with a periostracum ; valves equal, free, smooth-edged, often
gaping, variably sculptured ; adductor scars peripheral, sub-equal ; pallial line simple ;
area obscure or none; ligament parivincular, opisthodetic, external, often obsolete;
resilium usually internal, sub-umbonal or oblique; hinge plate narrow, channelled to
receive the resilium; hinge variable, normally consisting of one or two radiating

ORDER in TELEODESMACEA 4 1 1

a pair of lateral laminae in each valve, the anterior laminae often absent,
and the posterior frequently closely adjacent tn t}«- /v.</// /////,
Emulating cardinals. One Cretaceou^ and a numlii-r <>)'
Tertiary and Recent species. '^ X"X

Erycina (Lam.), Fischer (Fig. 750) ; Kelli". Tuilmi ;
Pythina, Hinds ; Lasea, Leach ; Lepton, Turton ; Erycinella,
Conrad ; Spaniodon, Reuss ; Fabella, Conrad., etc. Tertiary
and Recent.

Family 23. G-aleommidae. Gray.

Shell without a perceptible epidermis; valves equal, free, '„.//,/<-/,/,» inn

widely gaping ventrally, smooth, or variably sculptured ; Caicaire Grassier ; Fames. P.,
adductor scars distant, oval; pallial line JJj^ 0|,.; ; '.-.luva!'.

simple; ligament usually obsolete, resilium Greatly enlarged (after i>>-
internal, sub-umbonal, or oblique, attached 8 ayes'
to an excavated chondrophore in each valve; hinge plate hardly
developed ; laterals obscure or absent ; one or two cardinal teeth in
each valve or none. Tertiary and Recent.

Scintilla, Desh. (Fig. 751) ; Galeomma, Turton ; Passyia,
Sportella, Desh. ; Hindsiella, Stol. ; Ephippodonta, Tate, etc.

SciniiOa. parisiensis, Tertiary and Recent.
Desh. Upper Eocene ;
Auvers, near Paris. 2/3

(after Deshayes). Family 24. Chlamydoconchidae. Dall.

Shell cellulo-crystalline without an epidermis, comprising the prodissoconch with
narrow, long laminar accretions, very small; valves wholly internal, not connected, con-
tained in laterodorsal separate capsules, without hinge or hinge plate, not attached to
muscles or ligament ; ligament absent, resilium separately encapsuled between the obsolete
valves, functionless. Recent ; California.

The genus Chlamydoconcha, Dall, is evidently the last term in a series beginning
with forms like Lepton, and continued by Galeomma and Ephippodonta, but the
specialisation has been carried so far that it may well be regarded as the type of
a distinct family.

Family 25. Kelliellidae. Fischer.

Shell with a periostracum ; valves equal, free, closed, smooth externally with plttin
margins; pallial line simple; area obscure or none; ligament external, parivincnlar ;
resilium external or slightly sunken; hinge plate narrow, entire, with one or two
cardinals, and a single anterior lateral placed above the anterior cardinal tooth. Tertiary
and Recent.

Kelliella, Sars ; Lutetia, Desh.; ? Allopagus, Stol.; Turtonia, Forbes. Eocene to
Recent.

C. CYCLODONTA.

Teeth arched, springing from below the hinge margin, with the hinge plate obscure or
absent.

Superfamily 9. CARDIACEA. Lamarck.

Lobes of the mantle free behind the siphons, foot elongate, geniculate ; sculpture of
the shell chiefly radial ; cardinal teeth conical, the lateral laminae short, distant from the
cardinals.

412

MOLLUSCA
Family 26. Cardiidae. Fischer.

SUB-KINGDOM VI

Shell substance cellulo-crystalline, ivith the external layer more or less tubular ; valves
equal, free, gaping slightly behind, the beaks prosocoelous, the margins usually serrate or
radially striated; adductor scars sub-equal, the pedal distinct and usually distant;
ligament and resilium parivincular, external, short, set in a groove ; area obscure ; com-
plete hinge armature consisting of an anterior and posterior lateral in the left, and two

FIG. 752.
Cardiiim productum, Sow. Turonian ; St. Gilgen, Salzburg, 1/1-

anterior and one posterior lateral in the right valve, any or all of which may be absent ;
cardinal formula ^101Q, the teeth simple, smooth, never bifid, one cardinal in each valve
usually persistent, the others inconstant. Trias to Recent.

Cardium, Linn. (Figs. 752-754). Cordate, inflated, radiately ribbed or striated,

FIG. 753.

Protocardia bifrons,
Reuss. Turonian;
Strobl-Weissenbach am
Wolfgangsee, Austria.

Vi-

Cardium (Discors) discrep'ans, Bast.
Bordeaux, 1/1-

Miocene ; Dax, near

with prominent beaks. Represented by about 200 recent and over 100 fossil species.
Trias to Recent.

A very large number of sub-genera and sections have been proposed, based chiefly on the
external sculpture. Some of the more conspicuous groups are the following : —

Protocardia, Beyr. (Fig. 753). Cretaceous. Discors, Desh. (Fig. 754) ; Lacvicardium,
Swains. ; Serripes, Beck ; Hemicardium, Cuvier ; Papyridca, Swains. Tertiary and Recent.
Didacna, Eichwald, estuarine, leads toward the next family.

ORDER in TELEODESMACEA 413

Family ^7. Adacnidae. DalL

Like the Cardiidae, but thin-shelled, ivith long united siphons, a short compreszed
foot, a pallial sinus and obsolete
hinge armature, living in
brackish or fresh water. Ter-
tiary and Recent.

Adacna, Eichw. Shell
elongate oval, truncate behind,
gaping at both extremities ;
siphons very Ion-;, pallial ,-inns

deep. Miocene and Recent in

<<, , ; ,,, <Soo LimauHiutitom conjungeru, 1'artsdi. Pliocene (Congeria -

Caspian Sea. Brunn, near Vienna. 1/1-

Limnocardium, Stol. (Fig.

755). Cardinals weak, laterals strong, distant, pallial sinus moderate, shell Ho-eil
anteriorly. In brackish Miocene 'beds, especially the Sarmatir and Pontic horizons
of Eastern Europe, and in estuaries of the Aral, Black, and Caspian Seas.

Sub-genera: Prosodacna, Tourn. (Psilodon, Cob.); Monodacna, Eichw. ; Uniocardium,
Capell. ; Arcicardium, Fischer.

Superfamily 10. TRIDACNACEA. Menke.

Soft parts rotated forward nearly 180° with relation to the valves as compared with
normal Pelecypods, the anterior adductor wanting, and* the posterior nearly central in the
shell; cardinal teeth lamellar, oblique.

Family 28. Tridacnidae. Cuvier.

Shell very densely porcellanous, with no visible epidermis; valves equal free, with
a byssal gape, radially sculptured, with serrate margins and prosocoelous beaks ; ligament
and resilium as in the Cardiidae ; hinge with a single oblique cardinal in each valve, a
single posterior lateral in the left, and two in the right valve. Eocene to Remit.

Byssocardium, Mun.-Chalm., and Lithocardium, Woodw., of the Eocene, are per-
haps precursors of the recent Tridacna, Brug., and Hippopus, Lamarck.

Superfamily 11. ISOCARDIACEA. Ball.

Lobes of the mantle closed, except for the pedal and siphonal openings, smooth, double-
edged ; foot short, compressed ; sculpture of the shell faint or concentric ; cardinal teeth
lamellar, parallel with the hinge margin.

Family 29. Isocardiidae. Gray.

Shell substance cellulo-crystalline, the external layer not tubulate, with a marked
epidermis ; valves equal, free, rotund, completely closed, with plain margins and pro-
minent prosogyrous beaks ; adductor scars sub-equal ; pedal scar adjacent ; area not dis-
tinctly limited ; ligament and resilium external, parivincular, set in a deep groove, con-
tinuous to the beaks ; complete armature of the hinge with an inconstant posterior lateral
in each valve, and rarely, an anterior lateral close to the cardinals; cardinal formula

, the teeth lamelliform, and very variable in details of form. Jura to Recent.
B.0101

Many species have been referred to this group solely on account of their having gyrate
beaks. The Palaeozoic and many Mesozoic species so referred must be separated from
Isocardla.

414 MOLLUSCA SUB-KINGDOM vi

Isocardia, Lam. (Figs. 756, 757). Inflated, smooth, or concentrically striated ;
beaks distant, much produced, prosogyrate. Jura to Recent.

B

FIG. 750.
Isocardia striata, d'Orb. Portlandian ; Cirey, Haute-Marne (after Loriol).

Meiocardia, Adams. Keeled, concentrically ribbed. Tertiary and Recent.
? Clisocolus, Gabb. Cretaceous ; North America.

n

FIG. 757.
Hinge of Isocardia lumdatu, Nyst. Crag; Antwerp.

Family 30. Callocardiidae. Ball.

Shell as in the Isocardiidae, but with low and inconspicuous beaks, the valves more elong-
ated, and the lunule delimited by a sharp groove; cardinal formula j>T/)T~0fA- Tertiary
and Recent.

Oallogonia, Dall. Pallial line deeply sinuated, and a distinct anterior lateral close
to the cardinal teeth. Recent ; abyssal.

Callocardia, Adams. Rounded or Tapetiform, compressed, or not inflated, with
low inconspicuous, 11011 -gyrate beaks. Eocene and Recent.

D. TELEODONTA.

The most perfected type of modern teeth, to which, in addition to the normal (10101)
cardinal series of the ordinary Teleodesmacea, there is added in the most specialised types
(Veneridae, Mactridae) either a roughened area (Venus), a series of extra cardinals
(Tivela), or accessory lamellae (Mactra), rendering the hinge more efficient, or complicated.
The hinge characters of the less specialised forms hardly differ from the Diogenodonta,
but they are grouped here on account of their obvious affinities, as shoivn by other
characters.

Superfamily 12. VENERACEA. Menke.

Teleodonts with normal gills united to form a complete anal chamber, the mantle
lobes free behind the siphonal region, sub-equal adductors, an external parivincular liga-
ment seated in a groove, and the shell substance densely cellulo-crystalline with incon-
spicuous epidermis. Complete hinge formula ,,„>-— -07> of which a large

i\'£l . x 0 x UIOIOI. M

part is usually deficient.

ORDER III

TELEODESMACEA

1 1 r,

Family 31. Veneridae. Leach.

Valves equal, free, closed, with prosogyrous beaks, variably sculptured, will th<
margins more or less dentate, except in the smooth species; adductor scars peripheral,
pedal distant ; pallial sinus more or less sinuated, area very distinct ; resilium usually
external, embraced by the ligament; hinge plate developed; formula of the car* I ///.»/.<

kl^1010, with a single obsolete lateral in one valve; the cardinal* frequently /«/;/•/,

R010101

usually radially disposed and sub-equal in size, except the posterior left one, which is often

obsolete or obscure; supplementary cardinals or

rugosities are present in specialised forms. Jura

to Recent ; maximum in Tertiary and later.

The family must be divided into at least four
sub- families, as follows : —

a. Vencrinac : typical, with produced siphons,
not byssiferous, the young not retained within the
mother after leaving the egg.

b. Circinae : with separate short siphons, correla-
tive nearly simple parallel line, sub - internal,
partially amphidetic resilium, and compressed beaks.

c. Tapetinae : with long but partly separated
siphons, a byssus present at least in the young ;
hinge with no lateral teeth, otherwise like the
Venerinae.

d. Gcmminae: minute shells, with more or less
separated siphons, no byssus, obsolete lateral laminae,
and sheltering the nepionic young within the cavity
of the mother.

a. Pronoella, Fisch. (Pronoe, Ag. non Guer.
Me"n.) Compressed, pallial sinus very shallow ;

I • i ., i iii j- i i Cvpriiiie.riit i/ixci/x, Mutli. .sp. L'IMMT Cn-

a posterior lateral and three cardinals in each taceolis ; Oosau Vaii.-y, Austria.

valve. Jura.

Cyprimeria, Conr. (Fig. 758). Like the preceding, but the right valve with only

two cardinals, the hinder one bifid ; pallial sinus very shallow. Cretaceous.

Dosinia, Scop. (Artemis, auct.) Orbicular, lentiform, concentrically sculptured,

with a deep, well-marked
limule; cardinals 3:3; pallial
sinus deep, ascending, pointed.
Cretaceous to Recent.

Cyclina, Desli. Cretaceous
to Recent. Sunetta, Link
(Meroe, Sclmni.) ; Grateloupia>
Desm. Tertiary and Recent.
Venus, Linn. (Fig. 759).
Oval or rounded, plump,,
cordate, thick ; concentrically
or radially sculptured, with
denticulate margins ; hinge
plate broad, with three

cardinals in each valve and no lateral teeth; pallial sinus short, angular. Jura

to Recent; represented by about 200 fossil and as many recent species. Very

numerous sub-divisions have been proposed ; Venus s. s. is typified by V. mercenaria,

Lam.

Meretrix, Lam. (Cytherea, auct.), (Figs. 760, 761). Hinge with lateral teeth.

Tertiary and Recent.

Fit;. 759.
Venus cincta, Eichw. Miocene ; Gainfahrn, near Vienna.

416 MOLLUSCA SUB-KINGDOM vi

Tivela, Link. Hinge with supplementary cardinals. Miocene to Recent.

Meretrix semisulcata, Lam. Eo-
cene ; Grignon, near Paris.

FIG. 7
Meretrix incrasmta, Sow. Oligocene ; Weinheim, near Alzey. .

6. Circe, Schum. (Fig. 762). Umbones compressed, sculpture often divaricate,
ligament immersed. Tertiary and Recent.

Sub-genus Gouldia, Adams. Small, concentrically striated. Eocene to Recent.

Ptychomya, Agassiz. Cretaceous.

c. Tapes, Megerle (Pullastra, Sow.), (Fig. 763). More or less elongate, oval, with

narrow hinge plate, divergent and often bifid cardinals, 110

laterals, and deep ^j^^fes. pallial sinus. Cretaceous to Recent ;

about 150 living x^"*^"^^^ species.

Circe ex i mi a,
Hoernes. Miocene ;
Enzesfeld, near
Vienna.

FIG.

Tapes gregaria, Partsch.
Sirmatian Stage ; Wiesen,
ear Vienna.

Tapes (Baroda) fragilis, d'Orb. sp.
Cretaceous ; Gosau, Austria.

Upper

Of the numerous sub-genera Baroda (Fig. 764) and Iscanotia (Fig. 765), Stol., from the

Cretaceous, are remarkable for their elonga-
tion and the ridge-like form of the posterior
cardinal.

Oncophora, Rzehak. Differs from
Tapes in having a very short pallial sinus,
and the anterior adductor scar bounded by
a ridge. Miocene brackish water-beds.

Venerupis, Lam. Cardinal teeth 2 : 2-3,
strong ; a borer or nestler, often deformed.
Tertiary and Recent.

d. Gemma, Desk; Parastarte, Conr.; Psephis, Carp. Minute shells. Eocene to
Recent. «

Tapes (Iscanotia) impar, Zitt.
Gosau.

Upper Cretaceous :

ORDER III

TELEODESMACEA

417

Family X± Petricolidae. D'0rl>ignv.

I'uloes, when not <li*i<,rti>tl, r</n<t/, fr«, xomrirlmt .</"/"'".'/ Ix-Hnd, radiately sculpt" ml
with plain niiii-iit'ii* mi// /,iro,i.</iirnous beaks ; posterior adductor scar larger than tKe
pedal narrow, eloin/ot<tl^ ,tixiin <;t ; ligament and resilium external; area
or not defined; hinge without Intern/ Imuinae, with two or three small, us aall
radial cardinal t,-i-th in mr/i valve, ( Yetacrons to Recent.

Petricola, Lain.; Chorixlutlon, .lonas; and Xarntm/u, (Irav, an- the principal l'<inn>.

The family (;i,nic»i,iii«ri'd't'; of otnarine or fluvial ilr hal.it, appears to lie rrla1<-«l
to Petrinild, and include- tin- i-eccnt (Ho nnmiiin, (Bronn), Woodward, and T« n i/siphon,
Benson.

Superfamily 13. TELLINACEA. Blainville.

Siphon.-; dit&inct to ///»•//• Imxi't, itxinillii Ion// : /mll/ol I/in- ,s/ // inifr ; hi/n mr.nt external,

seated on nymphs : ///////< normally ivith an anterior and posterior lateral in each valve,
two radial cardinal*, of which the anterior is commonly oij'nl, mid somewhat pedunculated,
mid the pn*tt'ri<n\ n* n-i'll as the laterals, often obsolete.

Family 33. Tellinidae. Deshayes.

Shell substance cellulo-crystalline, with an inconspicuous epidermis; valves slightly
unequal, free, rounded in front, more or less rostrate, oblique, and gaping behind, com-
pressed, usually with smooth margins, low beaks, and variable, chiefly concentric sculpture ;
anterior adductor scar larger, frequently irregular ; pedal distinct; resilium embraced in

'l'iUi
ne;ir Ept-niay.

Fit:. 707.
Desh. Eocene Damery,

Fio. 766.

Tellina planatu, I^iu. Miocene; Putzleins-
<lorf, near Vienna.

Tellina (Linearia) bimdiatu, Zitt. Upper
Cretaceous ; Gosau, Austria.

the ligament, sub-external ; area narrow, small, covered with a dark epidermis, or fre-
quently obsolete; hinge plate narrow, anterior laterals approximate, posterior more
distant from the cardinals, when present; cardinal teeth small; pallial sinus deep,
discrepant in the opposite valves. Jura to Recent.

Tellina, Linn. Elongated, the rostrum more or less twisted ; two lateral teeth in
each valve. Jura to Recent.

Sub-genera : Tellina s.s. (Figs. 766, 767), Tcllidora, Mbrch ; Strigilla, Turtou ; Linearia,
Conr. (Arcopagia, d'Orb.), (Fig. 768), etc.

VOL. I

2 E

418

MOLLUSCA

SUB-KINGDOM VI

Macoma, Leach. Anal siplion long, branchial very short, hinge without laterals ;
shell smooth, less elongated than in Tellina. Tertiary and Recent.

Gastrana, Schum. (Fragilia, Desh.) Miocene and Recent.

Quenstedtia, Mor. and Lye. Long, oval, obliquely truncate behind ; beaks low,
pallial sinus shallow, only a single cardinal tooth present. Jura.

Abra upeli
near Vienna.

FIG. 709.
Ben. sp. Miocene ; Grund,

Family 34. Semelidae. DalL

Resembling the Tellinidae, but with the resilium internal, often on a distinct chondro-
pJwre, and with the laterals, when 'present, stronger and less distant. Tertiary to Recent,

Semele, Schum. (Amphidesma, Lam.) Shells large, rounded, thick, often conspicu-
ously sculptured ; 100 species. Tertiary and Recent.

Cumingia, Sow. Small, thin, with a spoon-
like chondrophore ; habit nestling. Tertiary
and Recent.

Scrobicularia, Schum. Differs from Semele
in having no lateral teeth. Tertiary and Recent.
Abra, Leach (Syndosmya, Recluz), (Fig. 769).
Smooth, small, thin ; cardinals 2 : 2, an anterior
and posterior lateral present ; chondrophore
narrow, oblique, not separated from the hinge line. Tertiary and Recent ; chiefly in
deep water.

Family 35. Psammobiidae. Dall.

Shell as in the Tellinidae, but usually more equivalve and less twisted, with more
conspicuous epidermis and nymphs, broader hinge
plate, and a wider posterior gape; lateral laminae
on the hinge wanting, and the cardinals sometimes
three in one valve; ligament external and conspicuous;
no defined area. Tertiary and Recent.

Psammobia, Lam. (Gari, Schum.), (Fig. 770).
(?) Cretaceous. Tertiary and Recent.

Pliorhytis, Conrad ; Asaphis, Modeer ; Sanguino-
laria, Lam. ; and Heterodonax, Morch. Tertiary and
Recent.

Family 36. Donacidae. Deshayes.

FIG. 770.

(Cal"

Valves equal, free, sub-trigonal, usually closed,
solid; outer surface and inner margins smooth or
radially sculptured, the posterior end usually shorter
and obliquely sub-truncate; pallial sinus similar in both valves ; resilium sub-internal,
sometimes amphidetic ; ligament short, external, seated in a deep groove, opisthodetic;
hinge plate moderately developed, usually with a posterior and anterior 'lateral in the

right, and corresponding sockets in the opposite valve; cardinal formula STyTTviJ ^ie
strongest cardinal tooth often bifid. Lias to Recent.

The resilium is chiefly opisthodetic and sub-internal, but some of the large species have a
small segment of the /esilium separate from the rest, wholly internal, and in front of the
beaks.

Isodonta, Buv. (Sowerbya, d'Orb.) Sub-symmetrical, convex, laterals strong, pallial
sinus deep. Jura.

ORDER III

TKLKODKSMACKA

419

Donax, Linn. (Fig. 771). Anterior -i<l<- lon^n, lateral* weak. rpper K«»cei.
Recent ; about 100 species. Sub-genus Iphigenia,

Schum. lien-lit.

/v/'/'/c, L-a. Lower KIMVIH-.

Superfamily 14. SOLENACEA. Lamarck

(emend.)

Dwellers in soft sea-bottom, narrow, elongated, /• miatian

modified for burrowing, gaping at both ends; foot 8

elongated, distally modified to serve as a piston or stilt within the burrow ; hinge without
lateral laminae.

Family 37. Solenidae. Leach.

Shell substance as in Tellina, but the external layer showing its cellular structure
more clearly ; with a pronounced epidermis ; valves equal, free, usually truncate at both
ends, and more or less inequilateral, ivith low beaks, smooth margins, not rostrate, smooth
or feebly sculptured ; adductor scars narrow, elongate, dorsally distributed, pedal distinct;
pallial sinus small in species with anterior umbones, and vice versa ; ligament and re-
silium external, parivincular, seated on nymphs; area obscure or none; hinge plate
hardly developed ; hinge often with a thickened ray crossing the valves and serving as a
buttress ; cardinals varying from one to four in each valve, usually a single slender
radial laminar cardinal in the right, and two in the left valve, with or without one or
two placed parallel with the hinge margin, simulating laterals; radial teeth usually
more or less pedunculated, rarely bifid. Devonian to Recent.

The Silurian forms heretofore referred to this family do not seem to belong to it, but
Palaeosolcn, Hall, is scarcely distinguishable externally from some modern forms ; its hinge,

FIG. 77-.'.

Sn/r,i xiilifrii-i/Uis, Eichw. Mioceut; (Sanna-
tian Stage) ; Pullendorf, Hungary.

Cultellus GHgnonem-i.^, Hi-sli. Calcaire
Orossier ; Grignon, near ParN.

however, is unknown. The species of this family are mostly much modified for a sp< -rial
mode of life, hence the variability in certain features, such as the siphons, foot, and frnna-

ture of the mantle lobes. Novaculina has been
naturalised in fresh water, and Tagelus apprar- t->
prefer estuaries.

Solen, Linn. (Fig. 772). Scabbard - shaped,

straight, with terminal beaks. Among tin- nunn-r-
ous sub - genera are : Ensis, Sebum. ; Pharella,
Gray ; Ceratisolen, Forbes ; Siliqua, Megerle ; Cul-
tellus, Schum. (Fig. 773). Tertiary and Rea-nt.

Palaeosolen, Hall. Devonian. Leptosolen,
Conrad. Cretaceous.
Solecurtus, Blainv. (Psammosolen, Risso). Cretaceous to Recent. Sub-genera :
Madia, Oken (Fig. 774) ; Tagelus, Gray; Novaculina, Benson, fresh water.

FIG. 774.

Solecurtus (Macha) Deshayesii, Desm. Cal
caire Grossier ; Grignon, near Paris. 1/1-

420

MOLLUSCA

SUB-KINGDOM VI

Superfamily 15. MACTEACEA. Gray.

Resilium internal, seated on chondrophores, left cardinal tooth bifid, fitting below the
two right cardinals, ^vhich are more or less joined together dorsally. Inner wall of the
mantle behind the siphons exhibiting a laminar sense organ.

Family 38. Mactridae. Gray.

Shell porcellanous, with an obvious epidermis, usually rounded-triangular, with
smooth or concentrically sculptured surface, smooth margins, and prominent prosogyrous
beaks ; valves equal, free, usually with a slight posterior gape ; area not limited ; liga-
ment variably external or internal ; resilium connecting sub-triangular chondrophores
usually excavated out of the hinge plate, rarely with a prop or buttress ; hinge plate well
developed, with normally an anterior and posterior lateral in the left, received into sockets
or paired laminae in the right valve, or obsolete; cardinals in the right valve two, with
their dorsal edges usually soldered together, and one bifid or deltoid cardinal in ilie
left, fitting below the former, a delicate accessory lamella often present in either valve, or
all may be more or less obsolete; siphons well developed, united, and usually with an
epidermal tunic ; adductors peripheral, sub-equal. Cretaceous to Kecent.

This group is so large and its extremes so variable, that it is best divided into sub-families,
as follows : l — Mactrinae, Ptcropsidinae, Lutrariinae, Zcnatiinae, and ? Anatinellinae.

Mactra, Linn. (Fig. 775).
separated by a shelly septum.

Ligament and resilium
Tertiary and Recent.

Sub - genera : Mactra s.s., Coeloinactra, Mactrodcrma,
Mactrotoma, Ball ; Mactrella, Gray.

Spisula, Gray. Ligament and resilium not separated,
the former more or less external. Cretaceous to Recent.

Mactra Podolica, Eichw. Miocene
(Sarmatian Stage) ; Wiesen, near
Vienna.

FIG. 776.
Lutraria elliptica, Roissy. Pliocene ; Rhodes,

Sub-genera : Hemimactra, Swains. ; Leptospisula, Call ; Cymbophora, Gabb ; tichizodcsma,
Gray.

Mulinia, Gray. Ligament and resilium immersed in the same socket. Miocene
and Recent.

Rangia, Desm. (Gnathodon, Gray, non Goldfuss). Like Mulinia, but with
elongated laterals, and the anterior lateral hooked at the umbonal end. Estuarine.

Pteropsis, Conrad. Eocene. Labiosa (Schmidt), Moller. Miocene and Recent.

Lutraria, Lam. (Fig. 776). Soleniform, hinge Mactroid. Tertiary and Recent.

Tresus, Gray (Schizothaerus, Com-.) ; Eastonia, Gray ; Heterocardia, Desh. Tertiary
and Recent. Zenatia, Gray ; Anatinella, Sow. Recent.

1 Cf. Dall, W. II., Synopsis of a Review of the Genera of Recent and Tertiary Mactridae and
Mesodesmatidae (Proc. Mai. Soc. vol. I. pp. 203-213), March 1895.

ORDER III

TELEODESMACEA

421

Family :v.). Cardiliidae. Dull.

Shell cord if <>r in, //•//// ///•',,// /'/».-/// y(/-<,so,////-,,//s //.•,//.•.<, „•///////, ////'//, rm/i<i//i/ sculptured ;
r adductor *-<ir /m/>r> >-W ////</,/ // radial myoj>li»r/r l<tinin<i, ///•• mit<-n'nr scar
tbngated, pallia! ////•• //»»/ .</// //»//.»/ .- //»/.//,;./(/ i-.i-f ITU n I, seated on nymphs; rerilium
internal connecting •j>n>jirtiiig chondrophorea ; hiti<i>' n-itlim/i ////./•///>. /,/// ///, cardinal
teeth as in Mactra. Tertiary in KVcriil.

Cardilia, De-lia\v>. Knct-ne ami

Family 40. Mesodesmatidae. Deshaye-.

,</<»'// xr///(/ »///</ Jinn-if, iitinilli/ Dnilili-fftiriil,

erect or opisthoyyrate beaks, otherwise as in the Mactridae;
siphons naked, not united. Tertiary to Recent.

Mesodesma, Desh. Tertiary and Recent. JA/'-
, (Jonr. Eocene. Atactodea, Dall (Paphia,
J^rya;, Swains.) ; Davila, Gray ; Anapella, Dall.
Recent. Ervilia, Turton (Fig. 777). Tertiary and
Recent. Caecella, Gray. Recent, fluviatile.

E. ASTHENODONTA.

Fi.:. 777.

<;i, Eicliw. Mi(iri-iic(8ar-
inatian Stage) ; Wiesen. in-ar Viuiuia. 1/1-

Hinge often essentially Mactroid, but usually degenerate or obsolete, owing to modi-
fications induced by the burrowing habit.

Superfamily 16. MYACEA. Menke (cm-end.)

Burrowing, long siphoned, frequently inequivalve Pelecypods, usually with the taunt If
lobes largely united below, more or less united siphons, and degenerate hinge apparatus.

Family 41. Myacidae. Woodward.

Shell substance cellulo-crystalline, earthy, with a conspicuous ////>/</•/,//.<.• rn //-..-.• un-
equal, more or Iras >'l»i></<ift>, rounded in front and gaping behind; adductor scars sub-

equal; pallial /in' ."in nut,, I ; fill,// ma rgi it*
jil«tn : urea obsolete or none: lnjn,,n,\\ ,i,nl
ri'xilium internal, opisthodetic, attached in flu'
left valve to a projecting chotukrophore merging
n-itli tin' <lnr*nl iinirgin behind, <nnl in tin
right valve to an inconspicuous, /'.>•//-///// x///<-
umbonal chondrophore ; hinge edentnlun.< :
siphons united, with a horny tunic, not i<-]\»Un
retractile. Tertiary and H«-<vnt.

o. 778.

Myaarenaria, Lin. Pleistocene (Glacial Deposit.-^ ;
Hohusliin, Sweden.

Linn. (Fig. 778). Snmnlli i-x-
Icrnally. Tertiary and Recent.

Surface

Sub - genera : Plalyodon, Conr.
decussated, siphon with horny
Cryptomya, Conr. Small, the pallial line discrepant in the two valves. N/<//"< -niu, Turtnii.
Minute, byssiferous, nestling. Tn<jnn-in, (!r;iy. Recent.

Family 4-2. Corbulidae. Fleming.

Shell small, much as in Mya, but the pallial line feebh' «r nl^ntfte, the ligament
usually sub-external, separated from the resilium, which is hit IT no!, alivincular, o,nd

422

MOLLUSCA

SUB-KINGDOM VI

79.

Corbula (Bicorbula) gallica, Lain.
Calcaire Grossier ; Damery, near
Epernay, France. Hinge, I/].

amphidetic ; the chondroplwre is received into a socket of the opposite valve, not merged
with the valve margin ; hinge with one or two sub-umbonal projecting teeth, and rarely

obscure traces of laterals ; the
A B posterior gape inconspicuous;

siphons short, united, naked,

wholly retractile. Trias to

Recent.

Corbula, Lam. (Figs. 779,
780). Small, ovate, rostrate,
very inequi valve, the right

A, Corbula cannata, Du]. J

Miocene; Potzleinsdorf, near valve convex, larger, with a

prominent tooth in front of
the pit for the resilium, left

valve with a flattened chondrophore, and usually a posterior tooth. Trias to

Recent.

Sub-genera : Erodona, Daudin (Azara, d'Orb. ; Potamomya, Sow.) Pallial sinus obsolete,
fluviatile. Pleistocene and Recent. JJothrocorbula, Gabb. With a lunule deeply indented
into the cavity of the valves. Tertiary and Recent. Corbulamella, Meek. With an anterior
myophore. Cretaceous. Anisothyris, Conr. (Pachydon, Gabb). Pliocene. Paramya, Conr. ;
Corbulomya, Nyst. Tertiary and Recent.

Family 43. Saxicavidae. Gray.

Shell substance as in Mya ; epidermis conspicuous; valves equal, free, rude, and often
irregular, more or less elongated and gaping, not fully covering the animal ; adductor
scars often irregular, the pallial

line discontinuous or irregular, A

the sinus distinct; shell margins
smooth; area obsolete; liga-
ment and resilium external,
parivincular, seated on strong
nymphs, sometimes widely ex-
tended ; hinge without laterals,
with few feeble or obsolete sub-
umbonal cardinals. Cretaceous
to Recent.

Saxicava, Fleuriau (Gly-
cimeris, Schum. ; Hiatella,
Daudin ; Byssomya, Cuvier ;
Agina, Turton). Hinge eden-
tulous in the adult, with one
or two cardinals in the young,
boring in the softer rocks.
Tertiary and Recent. Sub-
genus Panomya, Gray (Chaen-
opea, Mayer).

Panopea, Menard (Glyci-
meris, Lam. 1799, non Da
Costa), (Fig. 781). Large,
gaping widely behind and
slightly in front ; surface concentrically, or feebly sculptured ; an obscure tooth in
each valve. Cretaceous to Recent.

Cyrtodaria, Daudin (Glycimeris, Lam. 1801). Solenoid with strong epidermis.
Pliocene and Recent.

FIG. 781.

I'tni ojifM Mcnardi, Desh. Miocene; Vienna Basin. A, Dorsal
view of valves. B, Internal cast. C, Hinge plate seen from above, 1/2-

ORDER III

TELKODKSMAC'EA

423

Family 44. G-astrochaenidae. (I ray.

Shell substance as in ,sW/mo» : valve* .7/1, »/, /!•;»/./•/ guying /'// _/'/-../»/ : ,nl<lu,-tnr scars

the anterior smaller : jmlfinl >•/'/«/>• </••'//. ///"/•<////.-• >-//;,y//» : <//•«' /«///< ; /-•
res-ilium external, paririncular ; hi mi, /<•//// ^ .<//)////• <,/,>•„/,/,• »-,//•»/////// «/•

,,1, llhllnllti ; ilililllill frrif Ilintlil f

.1,1 external protective t»h<> to supplement
its burrow, but to which it is in no icay

( IVmiian. Trias to

Fie. 7M!.

Jl.-sli.

Eocene (Sables" inoyens) ;
Valniandois, near Paris.

]><:<li>n<l-

Middle

Jura; Balin, near Cracow.
Cast of burrow including
one of the valves, i/j.

This ^roiiji stands hetween tin- Mn<",,i
and A</'Xinacea, verging »>n tin- latter.
Many of its characters are adaptive, and are

repeat rd ill the h'/ixiji/<f>i><i<-<'i>, hut morpho-
logically its relations to the

,-eein

Gastrochcu rux,Spengler (C'A'" /*". l!.-t/. ;
Rocellaria, Blaiuv.), (Figs. 782, 783).
Bores cylindrical or pear-shaped cavities in rock, shell, or coral. Trias to .Knvni.

Fistulana, Brug. Secretes calcareous tubes which stand upright in the sand or mud.

Superfamily 17. ADESMACEA. Blainville.

Gills with direct and reflected laminae, lony, united^ extended into the
siphon ; posterior adductor usually in front of the visceral ganglion, anterior adductor
external to the cavity of the valves, exerted in a contrary sense to the posterior muscle ;
hinge margin reflected, edentulous; ligament obsolete; a myophoric process extending
freely into the valve from the sub-umbonal car if if.

Family 45. Pholadidae. Fischer.

Shell cellido-crystaUiiK, tritli » tit in epidermis; valves more or less goring in front
and behind, with inconspicuous beaks and reticulate, often spin<>« * -nljitnre; in tlw
adult supplemented by accessor// slu-Uij pieces, always- attached to the valves, but not by
nn t.rtt'rior shelly tube like tlxtf of th# Gastrochaenidae ; the antero-dorsal margins more
or less extensively reflected, the postrro-rentral approximated; pallial line sinuated, area
none ; ligament and rcsilium usually absent, an obsolete remnant of the resilium and
chondrophore sometimes present in the left valve. I Carboniferous, Jura to Recent.

Pholas, Linn. (Fig. 784). Surla< >• divided by grooves into areas which often have
diverse sculptuiv ; the adult often provided with accessory -lirlly plates, each of which

<; TS.J.

I-IKJH* l.,r<:*infi, Watelfit. Eoct-nc ; Cnisr <!.- la Motlir.

when seated in front of the beaks has been named a " protoplax," when above the
beaks, "mesoplax," when behind the beaks between the valves " metaplax," and when
between the valves ventrally (Martesia), " hypoplax." A calcareous septum, secret id
after the completion of the burrow, and occupying the pedal gape of the valves, is
called the " callum." The addition of these plates and appendages during growth so

424

MOLLUSCA

SUB-KINGDOM VI

changes the appearance of the shell that old and young stages have frequently been

described as specifically or even generically distinct.
Typical Pholads date from the Jura. Many sub-
genera have been named.

Tnrnus, Gabb (Fig. 785). Cretaceous. Martesia,
Leach (Fig. 786). Carboniferous to Recent. Jouan-

\ ' •iiLMF *vOi ^i^P net™' DeSm' Tertiary and Decent. Teredina, Lam.
l VI WM Valves in the adult stage soldered together and to ;i

thick adveiitive calcareous tube. Eocene.
Turntis (Xylapha-

f/ella) elegantuhts,
Meek. Upper Cre-
u s : Ida

t a c e o u s ; Idaho.
Enlarged (after
Meek).

Fi«. 786.

Murtcsia conoidc.a,
Desh. Eocene;
Auvers, near Paris.

Vi-

Family 46. Teredinidae. Scacchi.

Shell much reduced, equivalve, auriculate, widely
gaping, the valves apposited ventrally only on the
surface of a parietal tubercle: adductor scars unequal, the anterior marginal very
small; pallial line coincident ivith the valve margins: a
styloid myophore projecting from the cavity of the beaks :
mantle secreting a calcareous lining to the burrow ; pallets
variable in form, the valves without attached accessory shelly
plates; area none; hinge margin reflected, edentulous:
ligament absent or obsolete ; anterior adductor degenerate,
attached on the anterior edges of the valves, and covered only
by the mantle ; animal boring, chiefly in wood. Carbon-
iferous (?), Jura to Recent.

Teredo, Linn. (Fig. 787, A, C}. Pallets simple, spatuli-
form. Jura to Recent.

Xylotrya, Leach (Fig. 787, B}. Pallets articulated,
bipinnate. Tertiary and Recent.

The name Teredolites, Leymerie, has been proposed for
the casts of borings of fossil Teredos (Fig. 787, D}. The
problematical genus Polorthus, Gabb, from the American
Cretaceous, has been referred to this family. The Palaeo-
zoic species are known only by burrows, which are of
somewhat doubtful origin.

Vertical Range of the Pelecypoda.

A, Valves of the recent Temlo
Norveffica, Spengl ; inner and outer
views. Ji, Pallet of Xylot.rya s]>.
C, Pallet of Teredo -sp. D, Casts
of borings of Teredo TnnninH,
Leym. Eocene ; Kressenberg,
Bavaria.

Pelecypods make their appearance as extreme rarities
in the Lower Cambrian,1 being represented only by the

doubtful Ford-ilia and the tiny Modioloides. Even in the Ordovician they are still
rare. Modiolopsis, Ctenodonta, Palearca, Eopteria, and Glyptarca have been sparingly
found. In the Silurian a considerable augmentation of the number of bivalves is
observable, as many as eighty species having been distinguished in the fauna of the
small island of Gottland alone.

A very* marked difference in geological range is perceptible among the three orders
into which the class is divided. The Prionodesmacea, including most of Neumayr's
Palaeoconcha, are pre-eminently characteristic of the Palaeozoic faunas. Of the forty-
two families referred to this order, 110 less than nineteen occur in the Silurian, to which
seven are added during the Devonian, only three in the Carboniferous, and one in the
Permian. From these ancient stocks only seven Prioiiodesmacean families are evolved
during the whole of the Mesozoic, and but two in the Tertiary, while three are Recent.
Omitting offshoots, but four families cover the whole range of geologic time from

1 Cf. Wahott, C. />., Fauna of the Olenellus Zone (10th Ann. Rep. U. S. Geol. Surv., 1890).

OKHKKIII RANGE OV THE PELECYPODA ISI

the Silurian, and of the-e tin- recent n-piv-entat i\ .- an- everywhere n-cDgni.-ed a-
constituting tin- nio-t distinctively archaic type of pelec\ pod structure now exi.-t ing.

The order Anomalodesmacea i- represented in tin- Palaeozoic solely by it.- i-adical,
the /'//"/"'/'•///'/"'•; eight ,,)' its sixteen familie- originate in tin- Me.-o/ojc and Ti-rt iar\ .'
and, with tin- exception of tli.- /'//"/"'/'///'/"rand /'/</'/•-,/, ,,i<i<-i<l,i, , all have ciidun-d until
tin- present time. Only one family appears to lie exclusively Recent.

The Teleodesiiuict'-a aiv dist im-t i vely modern, although foreshadowed in the 1'ahn-o-

/oic by Cypricardian, Lucinoid, and Allodesmid radical.- the Solenoid radical i- .-till
questionable). 01' tur1y->«-v«-n i'aniilies thirty can l.e tii>t detinitely recognir-ed in the
Me.-o/ojc, twelve originate in the Tertiary, two are exclusively rer.-ni.and only a -ingle
one can lie traced continuously from the Palaeo/oic ID the recent fauna.

Of the Prionodesmaceau families, 1O5 ]>er cent .-urvive; of the Teleodesmacean 71
per cent ; and of the Anomalodesmacean SS per cent. If it wen- not for the mortality
amon<,' the dm imn-i'ii and Hii<Iixf<n; the i-atio of sui-vival amon<,r the Teleode.-marean
families would Ite !)5 per cent. Of 1O."> families which have been discriminated during
the whole history of the class 76, or about 72'3 per cent, are represented in tin-
ex i.-t ing fauna. Families have originated in the various geological epochs as follows : —
Cambrian 1, Silurian (Murchisonian) 20, Devonian 10, Carboniferous '•', 1'ermian -1,
Trias 13, Jura 14, Cretaceous 18, Eocene 15, Miocene and Pliocene :j, Pleistnr.-n.-
and Kecent 6. From this it appears that the development of the group, judged
by the increase of families., was most intense during the Silurian, thereafter rapidly
decreasing until the Trias, then gradually increasing until the Cretaceous, after which
the rate of differentiation again rapidly declined. It is noted that in the Palaeozoic
the Pelecypods form about one-quarter of all the mollusks known from this era ; in the
Jura and Cretaceous about one-half, and in the Tertiary about one-third of this number.

The Silurian is especially characterised by the presence of Taxodont, Palaeoconch, and
the older formsof Schizodont Pelecypods. The Prlastidae^Cardiolid<«',Anfiii/''iiridae,Cteno-
//'/>, /tiiln,', I'f<-riii<'i<l<ti', Ambonychndae, and Modiolopsidae are shared with the Devonian.

The Devonian has no families solely characteristic, but the brackish water Car-
diniidae, the Merjalodontidae, Trigoniidae, Pinnidae, Pectinidae, and Mytilidae fii-st
take rise in 1hi> period, and the sinupalliate Allorisma is the first Pelecypod showing
clear evidence of retractile siphons.

The Carboniferous is marked by the appearance of Parallelodvn and its allie.-,
the Li'iiiiilin- and Ostreidae, and some precursors of the Lucinacea and /'/"//<"/'"•> ".
The /\/-///'/"' and GastrochaeniJn • make their advent in the Permian ; but, on tin-
whole, the Carbonic fauna persists throughout this period. In the Trias, however,
important changes take place; many old genera disappear, and such forms a> A///"-y-
sidae, the ti-ue I'ninn^ SpondylvA, /'//////", the Pleuromyaadae^ Pholadomyacidae)
Astartidae, Lucinacea, Cardiidae, and Corbulidae enter upon the scene.

During the Jura, genuine Arcidae, Anomta, Eligmus, vsirioua Anatinacea, Cyrma,
/'/c,/v/x, /,s,;r" /•'//", and the Teleodont Veneridae, Tellinidae, Donacidae, and /'/'"/"'/"'•"'
are initiated. The character of the Cretaceous is strongly influenced by the aberrant
and short-lived Chamacea and Kudistids. The. Mutelidae, Pandoridae, Clavagellidae,
Poromyacidae, Crassatellitidae, Cr>n>t<>"nl,>nlae, Petricolid<«', true Solens, the Murtridn,,
and Saxicarnlin; also take their origin during this ]>eriod.

With the beginning of the Tertiary a gradual approximation to pn-eiit conditions
takes place. The Rudistae have disappeared, the Dysodonts are on the decline, and
the Telcodesmacean types on the increase. Numerous Anatinacea, Leptonacea, Tr!<l<n--
nidae, Callocardiidae, Semelidae, Mesodesmati(/<i<, and Myacidae ap})ear. At the close of
the Eocene, the wide distribution of many types now characteristic of warm, temperate,
or tropical waters begins to be restricted ; and during the Miocene the faunal boundaries
of mollusks depending upon tempera! ure conditions are laid down nearly on existing line.-.

The following table indicates more exactly the geological range of the families of
Pelecypods according to our present information : —

426

MOLLUSCA

SUB-KINGDOM VI

Families.

Cambrian.

Silurian.

D

p

Carboniferous.

1

£

a

•E

H

g

O

(b

w

1

1

Order 1. Prionodesmacea
I. PALAEOCONCHA
1. Solemyacidae .
2. Solenopsidae .
3. Vlastidae

"I

•

—

5. Cardiolidae
6. Antipleuridae
7. Praeeardiidae .
II. TAXODONTA

Superfamily 1. Nnculacea
8. Ctenodontidae
9. Nuculidae
10. Ledidae .

Superfamily 2. Areacea
11. Parallelodontidae .
12. Cyrtodontidae
13 Limopsidae

— —
—

=

— «

•^c— ^

14. Arcidae .

III. SCHIZODOKTA

Superfamily 3. Ptcriacea
15. Pterineidae .
16. Lunulicardiidae
17. Ambonychiidae
18 Pinnidae

—

19. Conocardiidae
20. Pernidae
21. Pteriidae
22 Myalinidae

^^~~

^—

^~~'

-^— —

=

.. ___

23 Vulsellidae

Superfamily 4. Ostracca
24. Ostreidae
25. Eligmidae

Superfamily 5. Naiadcu-ea
26. Cardiniidae .
27. Megalodontidae

—

-

^— »^

_

28 Unionidae

29 Mutelidae

Superfamily 6. Trigoniacea
31. Lyrodesmidae
32. Trigoniidae .

— —

—

RANGE OF THE PELECYPODA

427

Families.

Cambrian.

Silurian.

Devonian.

Tail >on iferous.l

i

^

•_'

X

IV. IsonoNTA

Superfamily 7. J'rcfinacca
33. Pectin idae

34. Spondylidae .
35. Dimyacidae .
36. Limidae .

m^^^

:— —

— —
-^^^«-

— —

_

—

—

Superfamily 8. Aii<>ini<"-'-«
37. Anomiidae

'

V. DYSODONTA
Superfamily 9. Myttlacca
38. Modiolopsidac

39. Mytilidae
40. Dreissensiidae

Order 2. Anomalodesmacea
Superfamily 1. Anatin<i<'c<i
A. EUSIPHONIA
1. Pleuromyacidae
2. Plioladellidae .

— ^-»

^^l^H

—

~

^—^—

3. Pholadomyacidae .

4. Anatinidae

5. Periplomidae .
6. Thraciidae

—

—

—

7. Myochamidae.
B. ADKLOSIPHOM A
8. Pandoridae

9. Lyonsiidae

10. Lyonsiellidae .

11. Chamostreidae
Superfamily 2. Bnriphaiuuea

12. Clavagellidae .
13. Euciroidae
14. Verticordiidae

—

—

—

—

15. Poromyacidae
16. Ctispidariidae .

—

—

—

—

428

MOLLUSCA

HUB-KINGDOM VI

Families.

,0

1

Silurian.

Devonian.

1
1

Permian.

1

H

i

•-S

B

i

I

S
1

9

K

K

Order 3. Teleodesmacea
A. PAXTODONTA

1. Allodesmidae .

B. DlOGENODONTA

Superfamily 1. Oypricardiacca
2. Pleurophoridae
3. Curtonotidae .
4. Astartidae

WWW

^•^^

-.•^—^

»-^—

— ^—

5. Crassatellitidae
Superfamily 2. Cyrenc«->'//
6. Cyrenidae
7. Sphaeriidae .

_

I

I

I

~

Superfamily 3. Cdrditaw
8. Carditidae

1

Superfamily 4. G'hamacca
9. Chamidae

10. Diceratidae .
11. Monopleuridae
12. Caprinidae

Superfamily 5. Riidistacca
13. Eadiolitidae .
14. Hippuritidae .

Superfamily 6. Lucin(t<-<-«
15. Tancrediidae .
16. Unicardiidae .

17. Lucinidae
18. Corbidae
19. Diplodontidae
20. Cyrenellidae .
21. Cryptodontidae

't...

...?.,

'I.

.^.^—

Superfamily 7. Leptonacco
22. Leptonidae

23. Galeoininidae .

24. Clilamydoconchidae

25. Kelliellidae .

C. CYCLOIXIXTA

Superfamily 8. Vardiacea
26. Cardiidae
27. Adacnidae

Superfamily 9. Tridacnaa'K
28. Tridacnidae .

—

RANGE OF THE PELECYPODA

429

Fainili.-s.

Cambrian.

00

i 1
! I

± -:-

c

1

I \

Z

i

Superfamily 10. fsn<-iiritiii<;;t.
29. Isocardiidae .
30. Callocardiidae
D. TKI.KUIHIN \-\

Superfamily 11. Vcneracca
31. Veneridac
32. Petricolidae .
Superfamily 12. Ti'llinacca
33. Tellinidae
34. Semelidae
35. Psammobiidae
36. Donacidae
Superfamily 13. Solencuxa
37. Solenidae
Superfamily 14. Mactracea
38. Mactridae
39. Cardiliidae .
40. Mesodesmatidae

E. ASTHENODOXTA

Superfamily 15. Myacea
41. Myacidae
42. Corbulidae .
43. Saxicavidae .
44. Gastrochaenidae
Superfamily 16. Adcsmacai
4.o. Pholadidae
46. Teredinidae .

i

'i

/

~~~

—

^^— —

/ .

_

— ^—

— ^—

.._

—

[Grateful acknowledgments are due to Dr. W. H. Dall, of tlie United States National
Museum, for having revised and in large part rewritten the preceding chapter on the Pelecypod.s.
It is to be regretted, however, that limits of space necessitated a partial abbreviation of the
original text, for which the Editor alone is responsible. — TRANS.]

430 MOLLUSC A SUB-KINGDOM vi

Class 2. SCAPHOPODA. Bronn.1

(Cirrhobranchiata, Blainville ; Solenoc&nchia, Lacaze-Duthiers ;
Prosopocephala, Stoliczka.)

Aquatic, marine, bilaterally symmetrical Mollusks, protected by an external,
tubular, somewhat curved and tapering shell, open at both ends, the concave side
of which is dorsal ; the shell secreted by a mantle of the same shape, the larger,
anterior opening of which is provided with a circular muscular thickening, the smaller
opening serving as outlet for organic waste and genital products. Mouth furnished
with a radida, borne on a cylindrical snout, and surrounded by a rosette of leaf -like
appendages ; a cluster of numerous exsertile filaments (captacula) springing from its
base. Otoci/sts present, but no eyes or tentacles. Foot rather long, conical, with
lateral lobes, and adjacent to the snout ventrally.

Gills are wanting, the general surface assuming respiratory functions. Liver
large, bilateral ; intestine, strongly folded, the anus ventral and rather anterior, and
kidney orifices adjacent to it. Heart rudimentary, with a. single chamber. Nervous
system with well-developed ganglia united by commissures. Reproduction without
copulation, the sexual products voided through the right kidney.

Scaphopods are without exception marine, and for the most part inhabit
deep water. There are no littoral species. They live embedded in mud or
sand, with only the smaller end of the shell projecting above the surface.
Their food consists chiefly of Foraminifera and similar organisms, captured
by the filamentary captacula.

The tubular, curved shell, open at both ends, is characteristic of the class,
the tubular shells of certain Gastropods and Cephalopods being invariably
closed at the smaller end. Some tubicolous Worms (Serpulidae) form a similar
shell, but it is composed of two layers only, instead of three
as in Scaphopods, the growth is more irregular, and its micro-
scopic structure very different.

The shell of Scaphopods increases by successive increments
at the larger end, and at the same time loses by wear and
absorption at the smaller end. The posterior slits or notches
occurring in some species are therefore formed by reabsorption
of the previously solid shell wall, and have a genesis wholly
different from the slits or fissures of Pleurotomaria, Fissurella,
(y) and other Gastropods.

Various genera described as Scaphopods have since been
p r cndonMowt f°und to belong to the Serpulidae. Such are Pyrgopolon, Montf.
Montf. upper ere- (Fig. 788), from the Maestricht of Belgium, also known as
Entalium, Defr., and Pharetrium, Konig; and Hamulus, Morton
(Falcula, Conrad), of the American Cretaceous. The Cambrian genus Spiro-
dentalium, Walcott, in which the shell has spiral striae, is at present too

1 Literature (see also, under the head of Mollusca, pp. 344, 345) :
Deshayes, G. P., Anatomic et Monographic du Genre Dentale (Mem. Soc. Hist. Nat., Paris, vol. II.

pp. 321-378), 1825.
Lacaze-Duthiers, 11. de, Histoire de 1'organisation et du developpment du Dentale (Ann. des Sci.

Nat. [4], vols. VI. -VIII.), 1856-57.

SCAPHOPODA 1:5 1

imperfectly known to justify'its reference to the Scaphopods, or even to the
MolluBca.

r'amily 1. Dentaliidae. Gray,

Scaphopoda ha rim/ ,< n,nic foot with an encir<-l/'n<i Outfit upanded laterally and
int'.-n-npted dorsallij. Shell tubular, curved, /vr////,//-/// tnf,, /•/,/,/ //,/•„ „,,/,„/'/, not contracted
anteriorly, sculptured or smooth. Ordovirian t" Ueeent.

Dentalium, Linii. (Figs. 789, 790). Character- those of tin- family. Heginiimg
with a few species in the Ordovician, tin- number inen-a.-e.- .-lowly until tin- ( jetaceou-.
A great acceleration then ensues, which continues to tin- piv.-ent.
About 275 fossil and 150 recent species known. Various authors have #
attempted to .subdivide the genus upon characters of the posterior .-lit
of the shell, but this has proved to vary widely even among individuals.
The following sub-genera based upon the system of sculpture and ,-hape
of the tube appear more >table : —

I filial in in. s. str. (Fig. 789). Shell with strong longitudinal ribs, apical
notch short or wanting. Eocene to Recent.

.1, /f alts, Adams (Entails, Gray 11011 Sowb. ;
Entaliopsis, Newton and Harris), (Fig.
790, A}. Shell with longitudinal riblets or
striae at least in the young ; apex with a
short ventral slit and a sheath. Cretaceous
to Recent.

Heterosehisma, Simr. With longitudinal
riblets and a dorsal slit. Recent.

Fissidentalium, Fischer. Large and solid,
with many longitudinal ribs or striae ; a long
ventral slit usually present. Eocene to
Recent. Schizodentalium, Sowb., in which
the slit is interrupted into a series of holes,
is probably a modification of this group.

tJi-iiptiiciin', Pils. and Sharp. Surface with
close, tine longitudinal striae near apex only,
or throughout. Tertiary and Recent.

l.iifrl,!,-,!!, ilium, Cossm. Arcuate, smooth,
with growth-lines only, circular in section,
apex simple or notched. Silurian ? to Recent.

Ithabdiis, Pils. and Sharp. Smooth,
glossy, nearly straight, sub-circular in section,
apex entire. Recent.

ti/if.xijt/i»n. Pils. and Sharp. Small and very slender, smooth, the apex generally with an
inserted tube. Oligocene to Recent.

Compressidena, Pils. and Sharp. Small, much tapering, vertically compressed, smooth.
Eocene to Recent.

Lobantale, Cossrn. Shell compressed, with two internal longitudinal ribs. Eocene.

Fustiaria, Stol. (Figs. 790, B, C). Shell with a very long and linear ventral cleft posteriorly.
Cretaceous to Recent.

Pro. T'.'

A, D. (A Htiii;*) Kni,., •:, Nyst. (

oceiit- ; Wrinhcini. near Alxt-v.
D.(Fustiaria)lucida. Drsli. Eocene;
Guise la Mothe. Vi- <-',
portion of saiins
slit.

\^-

/,',

Pip,
Denial

"ii'inlmr, Lain.
Pliocene ; Asti,
Italv.

Sars, J/., Oni Siphonodentaliiiin vitmim. en ny Slaegt af Deutalidernes Familie. rnivei>itots-

Program, Christiana, 1861.

Stoliczka, J>\, Palaeontologia Indica. Cretaceous Fauna of Southern India, vol. II., 1867-68.
Gardner, J. &, On the Cretaceous Dentaliidae (Quar. Jouru. Geol. Soc. London, vol. \.\.\IV. j.p.

56-65), 1878.
Kovalevsky, A., ^tude sur rembryogenie, etc., du Dentale (Ann. Mas. iIi-4. Nat., Marseille, Zoologie

Mem. No. I.), 1882-83.
Plate, L,, Ueber den Ban utid die \fr\vandtschafts-Bezieliungen der Solenocouchen (Zool. Jaln-1).,

Abtheil. fiir Auat. und Ontog., vol. V. pp. 301-386), 1892. [Bibliography, pp. 384-386.]
Simroth, H., Mollusca in Broun's Classen uud Ordnuugen des Thierreichs, vol. III. pp. 356-467.

1893-95.

432 MOLLUSCA— AMPHINEURA SUB-KINGDOM vi

»

Plagioglyptti, Pils. and Sharp. Surface with extremely oblique, sinuous, encircling striae
(D. undidatum, Miinst.) Carboniferous to Trias.

Family 2. Siphonodentaliidae. Simroth.

Scaphopoda having the foot either expanded distally in a symmetrical disk with
crenate continuous edge, or simple and vermiform, without developed lateral processes.
Shell small and generally smooth, often contracted towards the mouth. Cretaceous to
Recent,

Although this family is usually characterised by a small smooth shell, the essential
difference from the Dentaliidae is in the form of the foot. Typical forms of Cadulus

appear in the Cretaceous ; the remaining
D genera are Tertiary and Recent.

Entalina, Monts. Shell Dentalium-Iike,
largest at the aperture, thence tapering to
the apex ; strongly ribbed, and angular in
section near the apex. Miocene to Recent,

Siphonodentalium, Sars (Pulsellum, Stol. ;
Siphonentalis, Sars). Shell an arcuate,

791. slightly tapering tube, circular in section

A, Cadulus (Poiyschiik*) di'nti.niiatiix, Desh. Cai- or nearly so, and smooth externally. Apex
caire Grossier ; Damery, near Epernay. B, Cadulus ,, -, • n i«j. • -A i T.

(inwhitin) htflssunitus, Uesh. Caicaire Grossier; rather large, typically slit into lobes, but
Grignon, near Paris c, uuiuius omhnn Phil. Tor- sometimes simple. Pliocene to Recent,
toman ; Monte Gibbio. D, Cadulus olii-i, 8cac. Tor-
tonian ; Monte Gibbio, near Sassuolo, Italy. Cadulus, Phil. (Gadus, Desll. ; Gad^la,

Gray; Helonyx, Stinip.), (Figs. 791, G, D).

Shell tubular, circular or oval in section, swollen near the middle, or anteriorly, con-
tracting toward the aperture. Cretaceous to Recent.

Typical forms with simple anal orifice appear first in the Cretaceous, Dischides,
Jeffr. (Fig. 791, B\ with two lateral slits, and Polyschides, Pils. (Fig. 791, A), with
several notches appear in the Eocene. All continue to the present.

Class 3. AMPHINEURA. Ihering.1

tic, marine, bilaterally symmetrical Mollusks, with the head partially or not
differentiated ; in form worm-like with a ventral groove or none, or oval, flattened,
with a foot adapted for creeping. Nervous system consisting of an oesophageal ring
with ganglia and four longitudinal cords, two ventral and two lateral ; no cephalic
eyes, tentacles, or otocysts. Gills paired or many, posterior or lateral ; mouth anterior,
usually with a radula ; anus posterior, median. External surface with a series of
shelly plates, or stiffened with calcareous

1 Literature :

Jhering, H. v., Vergleichende Anatomic des Nervensystems und Phylogenie der Mollusken, 1877.
Doll, W. H., On the Genera of Chitons (Proc. N. S. Nat. Museum, vol. IV. p. 279), 1881.
Hubrecht, A. A. W., A Contribution to the Morphology of the Amphineura (Quar. Jouru. Microscop.

Soc., vol. XXII. pp. 212-227), 1882. [Bibliography, pp. 226, 227.]
Rochebrune, A. T. de, Monographic des especes fossil es appartenant a la classe des Polyplaxiphores

(Ann. Sci. Geol., vol. XIV. pp. 1-74), 1883.
Pruvot, G., Sur 1'organisation de quelques Neomeniens des Cotes de France (Arch. Zool. Exper. et

• Gener. [2], vol. IX. pp. 699-805, 1891. [Bibliography, pp. 702, 703.]
Pilsbry, H. A., Monograph of the Polyplacophora. In Tryon and Pilsbry's Manual of Conchology,

vols. XIV. and XV., 1892-93.

ORDER ii APLACOPHORA— POLYPLACOPHOifA

Order 1. APLACOPHORA.

Body vermiform with <> />•/<//•<// groove, tin- skin elsewhere beset with calcareous
spicules; no dorsal shell ij plates in tin' ml nit.

This is a degenerate group, represented in the recent fauna by about a
dozen genera belonging to two families — Chaetodermatidae and j\V».///r///W»//.
Fossil remains are unknown.

Order 2. POLYPLACOPHORA. Blainville. Chitons.

Amphineura protected by a dorsal series of eight shell ij mires ami im <-///•//>•//////
girdle; with differentiated hem/, ami a ventral sole or foot adapted t<> wy/'/'v .- //;//>•
numerous, occupying the groove between foot ami girdle ; radula present, heterodont ;
sexes separate.

The external covering in the Polyplacophora, or Chitons, consists of eight
valves bound together by an encircling flexible band called the girdle. The
anterior or head-plate (Fig. 792, A, below) is invariably semicircular, with the
apex or mucro at the middle of the straight margin ; the six succeeding plates
are generally square (Fig. 793, below), with the apex posterior on the median
line ; and the posterior or tail- valve (Fig. 792, B) is semicircular or subcircular,
with apex varying in position from in front of the middle to the hind margin.
All of the plates are composed of two layers — an outer porous layer, the
tegmentum, and an inner porcellanous one, the articulamentum. In most of the
lower Chitons these layers are coextensive and have smooth edges ; but in
the higher forms the articulamentum projects beyond the outer layer into the
substance of the girdle, in which it is firmly inserted. These projections at
the outer or peripheral margin are termed insertion plates. They are generally
slit or notched into so-called " teeth," which may be either smooth and sharp
along the edge, or crenulated (pectinated}. Insertion plates serve the function
of binding the valves firmly to the girdle.

The anterior margin of each valve except the first one invariably shows
two projections of the articulamentum called sutural laminae (Figs. 792, B,
793), which pass under the rear margin of the next anterior valve, thus pre-
venting vertical displacement of the series. The tegumentum is traversed by
a multitude of fine canals which terminate at the surface idttunute sense
organs. The position of the latter in dry or fossil valves ; ~fl He as a fine
quincuncial punctation. In the highest Chitons a certain iHraoer of these
sense organs have become enlarged and modified into eyes, easily recognised
as pigmented dots in recent, and small pits in fossil specimens. I

Polyplacophora make their appearance as early as the Ordovicfen ; they are
rare in the Silurian and Devonian, but somewhat more aburl|ant in the
Carboniferous. None of the Palaeozoic genera (Eoplacophora) are known to
continue into the Mesozoic, but are replaced by types more related to modern
Chitons (Mesoplacophora}. Members of the most specialised sub-order, Teleo-
placophoi'a, are first encountered in the Eocene, although they doubtless arose
earlier. About -twenty Palaeozoic, five or six Mesozoic, and fifty Tertiary
species have been described. Recent forms number several hundreds.
A good many species supposed to be Chitons have been based^fcui barnacle
VOL. I \ 2 F

nise^Mwi

434

MOLLUSCA

SUB-KINGDOM VI

valves, fish scales, and other fragments. The recently described Duslia
insignis, Jahn, is apparently a Crustacean ; certainly not a member of the
Polyplacophora.

Three sub -orders are recognised, according as the insertion plates are
absent, or if present, unslit (Eoplacophora) • developed, smooth, and slit into
teeth (Mesoplacophora) ; or both slit and pectinated (Teleoplacophora).

I

Sub-Order A. EOPLACOPHORA. Pilsbry.

Polyplacophora with the tegumentum coextensive with the articulamentum, or ivith the
latter projecting in smooth, unslit insertion plates ; gills posterior.

Family 1. G-ryphochitonidae. Pilsbry.

Insertion plates absent, sutural laminae small; one or both end-valves ivith the
terminal margins elevated ; form elongated and narrow. Palaeozoic.

Helminthochiton, Salter. Valves thin, mucro sub -central, low; end -valves not
elevated terminally. Silurian.

Priscochiton, Billings. Similar in the non-sinuous head-valve, but beaks of the
valves greatly produced backwards. Orclovician.

Gryphochiton, Gray (Fig. 792). Elongated, with small beaks and very small sutural
laminae; terminal margins of end-valves strongly elevated; tail-valve with low,
decurved mucro behind the middle. Carboniferous.

Pterochiton, Cpr. (Anthracochiton, Eochebr.). Elon-
gated, the valves strongly beaked and laterally excavated ;
tail -valve with depressed post -median mucro and no
posterior sinus, anterior valve with the front margin
elevated, sutural laminae large. Carboniferous.

Cymatochiton, Dall (Protalochiton, Eochebr.). Oval,
elevated and granular, the valves short and wide, with
small, low sutural laminae and distinct lateral areas ;
mucro of posterior valve post-median, elevated. Permian.
Probolaeum, Cpr. Elongated, elevated ; valves very
strongly beaked, the pleura projecting beyond the jugal
tract ; anterior valve sinuate in front, posterior valve
unknown. Devonian.

Chonechiton, Cpr. Median valves as in Gryphochiton ;

with the mucro
thrown backward, as in Gryptoplax.
Carboniferous.

Somewhat like the recent Lorica, but
without insertion plates. Carboniferous.

Family 2. Lepidopleuridae. Pilsbry.

T .. Sandb. ^Miocene ; Wald-

insemon plates absent, or present and unslit ; end-valves bockeiheim, near Creuz-

toith the terminal margins never elevated; form oval or oblong, "nda Serior'vah-e!16^"
Tertiary and Eecent.

Lepidopleurus, Eisso (Leptochiton, Gray), (Fig. 793). Small, oval ; insertion plates
entirely absent, sutural laminae small ; girdle minutely scaly or chaffy. Eocene to
Eecent.

FIG. 792.

Gryphochiton priscus, Munst.
Carboniferous ; Tournay, Belgium.
A, Anterior and three intermediate ,
valves. B, Posterior valve, ventral posterior valve
and dorsal as

Hanleya, Gray.
plate, and

Like the last, except that the anterior valve has an unslit insertion
is spiculose. Champlain to Eecent.

ORDER ii POLYPLACOPHORA 435

}r>i,tinrthrum, Cpr. Both anterior and posterior vahvs with smooth tm.-lit
insertion plates, the others lacking them; girdle downy, with small sutural pores.
Recent.

Choriplax, Pik Valves partly immersed in the minutely granulose girdle, all
with thin, smooth insertion plates. Recvnt.

Sub-Order B. MESOPLACOPHORA. Pilsbry.

Insertion plates developed, slit, not vcrtn-nl!,/ grooved »r ji«-ti,i,itcd outside.

Family 1. Ischnochitonidae. Pilsbry.

Valves having the inner layer well covered by the outer. Surface of intermediate
valves divided into lateral and central areas by a diagonal rib (often indistinct), extending
from the beak to each anterior 'outer angle of tegumentum ; or when this is not clearly the
case, the posterior valve has a crescentic series of well-developed teeth ; all valves with
slits. Eocene to Recent.

Two sub-divisions of this family are recognised, according as the anterior and side
slits correspond in position with ribs on the external surface or not Among the
genera included under the first head (Callistoplacinae) may be mentioned the follow-
ing : — Callistochiton, Nuttallina, and Callistoplax, Carpenter ; Craspedochiton, Shuttle-
worth ; and Ceratozona, DalL Representatives of the second sub-family (Ischnochitoninae)
are as follows : — Schizoplax, Dall ; Tonicella, Trachydermon, and Dinoplax, Carpenter ;
Callochiton and Ischnochiton, Gray ; Chaetopleura, Shuttleworth.

Family 2. Mopaliidae. Pilsbry.

Valves externally divided normally into central and lateral areas, the posterior valve
with a sinus behind, one or two slits on each side of it or none ; intermediate valves each
ivith a single slit ; teeth smooth, sharp, often with thickened edges on the outside ; girdle
more or less hairy. Pleistocene and Recent.

This family comprises the following genera : — Mopalia and Plaxiphora, Gray ;
Placiphorella, Carpenter ; and Placophoropsis, Pilsbry

Family 3. Acanthochitidae. Pilsbry.

Valves more or less immersed in the smooth or hairy girdle, the tegmentum therefore
much smaller than the articulamentum ; the exposed surface divided into a narrow dorsal
and wide latero-pleural areas, the latter formed by the union of the lateral and pleural
areas of normal Chitons. Insertion teeth sharp, rarely smooth ; posterior valve either slit
like the head-valve, or having a posterior sinus; head-valve USIK&I trith Jive slits,
intermediate valves singly slit. Body never vermiform. Pliocene to wecent

The following representatives are to be cited : — Acanthochites, Risso ; Spongiochiton,
Carpenter ; Katharina and Amicula, Gray ; Cryptochiton, Midd. and Gray.

Family 4. Cryptoplacidae. DalL

Elongated or vermiform Chitons with small valves; insertion and sutural plates
strongly drawn forward, sharp and smooth; the anterior valve with three to five slits, ///••
others ivith one slit on each side, or none ; tail-valve having the mucro far posterior,
insertion plate continuous behind; girdle very thick and wide.

This is a highly specialised branch of a low group of Chitons, unknown in tli<-
fossil state. Cryptoplax, Blainville (Chitonellus, Lam.), and Choneplax, Carpenter, are
examples.

436 MOLLUSCA — GASTKOPODA SUB-KINGDOM vr

Sub-Order C. TELEOPLACOPHORA. Pilsbry.

All valves, or the first seven, with insertion plates cut into teeth by slits; the teeth
sharply sculptured (pectinated) outside by fine vertical grooves.

Family 1. Chitonidae. Pilsbry.

Characters those of the sub-order. Tertiary and Eecent.

The family is illustrated by the following genera, of which only the first two occur in
the fossil condition : — Chiton, Linne ; Trachyodon, Ball ; Eudoxochiton, Shuttleworth ;
Tonicia, Schizochiton, Enoplochiton, and Onithochiton, Gray ; Acanthopleura, Guilding ;
Lorica, Adams ; Loricella and Liolophura, Pilsbry.

Class 4. GASTROPODA. Snails.1

Mollusks with distinct head, soled or more rarely fin-like foot, and undivided
mantle, which latter secretes a simple, spirally wound, or saucer-shaped shell.

Gastropods differ from Pelecypods in having a more or less distinctly
marked head, which usually bears tentacles, eyes, and ears, and contains a

1 Literature (see also under the head of Mollusca, pp. 344-345) :
d'Orbigny, A., Paleontologie francai.se. Terrains cretaces, vol. II., 1842. Terrain jurassique, vol.

II., 1850, and vol. III. (continuation by Piette), 1867-91.
Beyrich, E., Die Conchylien des norddeutschen Tertiargebirges (Zeitschr. deutsch. geol. Gesellsch.,

vols. V., VI., VIII.), 1853-56.
Troschel, F. H., Das Gebiss der Schnecken, zur Begriindung einer natiirlichen Classification, vols. I.,

II., Berlin, 1856-78.

Billings, E., Palaeozoic Fossils, vols. I. and II., Montreal, 1865-74.
Stoliczka, F., Cretaceous Fauna of Southern India, vol. II. Gastropoda (Mem. Geol. Survey, India),

1868.
Salter, J. W., A Catalogue of the Collection of Cambrian and Silurian Fossils in the Museum of

Cambridge, 1873.
Zittel, K. A,, Die Gastropoden der Stramberger Schichten (Palaeont. Mittheil. Mus. bayer. Staates,

Bd. II. Abtheil. 3), 1873.
Ihering, H. von, Vergleicheude Anatomie des Nervensystems und Phylogenie der Mollusken.

Leipzic, 1877.
Hoernes, R., and Auinger, M., Die Gastropoden der Meeresablagerungen der ersten und zweiten

miocanen Mediterranstufes. Vienna, 1879-92.
Koninck, L. G. de, Faune du calcaire carbonifere de la Belgique (Ann. Mus. d'hist. uat. de Belgique,

vol. VI. pt. 3, and vol. VIII. pt. 4), 1881-83.
Lindstrom, G., On the Silurian Gastropoda and Pteropoda of Gotland (K. Svenska Vetensk. Akad.

Handl., Bd.XIX. Heft 2), 1881.

Quenstedt, F. A., Petrefaktenkunde Deutschlands, Band VII. Gastropoden. 1884.
Hudleston, W. H., A Monograph of the British Jurassic Gasteropoda (Palaeontographical Society),

1887-94.

Philippi, R. A., Die tertiaren und quartiaren Versteinerungen Chiles. Leipsic, 1887.
Koken, E., Ueber die Entwickeluug der Gastropoden vom Cambrium bis zum Trias (Neues Jahrb.

fur Mineral., Beilage, Bd. VI.), 1889.
Koken, E., Die Gastropoden der Trias urn Hallstadt (Abhandl. k. k. geol. Reichsanstalt, Wien, Bd.

XLVI. Heft. 1), 1896.
Kittl, E., Die Gastropoden der Schichten von St. Cassian der siidalpinen Trias (Ann. k. k. naturhist.

Hofmuseums, vols. VII., VIII.), 1891-92.

Newton, R. B., Systematic List of British Oligocene and Eocene Mollusca. 1891.
Dall, W. H., Contributions to the Tertiary Fauna of Florida (Trans. Wagner Free Inst. Sci., vols.

III., IV.), 1895-97.
Vinassa de Regny, P. E., Synopsis dei molluschi terziari delle Alpe venete (Palaeoutogr. Italica,

vols. I., II.), 1896-97.
Harris, G. F., The Australasian Tertiary Mollusca (British Museum Catalogue of Tertiary Molluscn,

Part L), 1897.

>i\ «;ASTROPODA 437

large cerebral ganglion. The ventral aspect of the creature is commonly
formed by a broad foot; but in the JI<f>r<>/><>da this is modified into a vertical,
laterally compressed fin; and in the /'/</"/""/" it is represented by t\v«» \\in^-
like swimming membranes near the head. The base of the foot is sometimes
of considerable size, and in some forms (Strombidae) the animal is enabled to
spring quite a distance by contracting the foot. The mantle lobe is el<
along the back like a hood, extending as far as the head, and usually secretes
a shell from its outer surface. The shell covers the intestinal sac and lung
cavity, and usually permits of retraction into it of the entire body of the
animal. Body and shell are united by muscular attachment ; in spiral shells
the muscle is fastened to the columella, but in bowl-shaped forms to the inner
surface of the shell.

The nervous system consists of two cerebral ganglia, the paired pedal and
visceral ganglia, and two or three additional pairs, all of which are united by
commissures. A complete crossing of the commissures of the visceral ganglia
sometimes takes place (Chiastoneura), but in other forms they run parallel
(Ortlioneura).

The peculiar armature of the mouth, although developed in all classes of
Mollusks except Pelecypods, is especially characteristic of Gastropods. This
consists of two jaw-like horny plates on the upper wall of the oesophagus,
opposed to which is a chitinous grating, strap, or radula, resting upon the
tongue or odontophore. The tongue itself is merely a swelling at the bottom
of the buccal cavity. The radula is usually quite long, and is beset with
innumerable small teeth or hooks, placed in transverse and longitudinal rows.
The exceeding diversity of the radula amongst the different groups was
advantageously employed by Loven and Troschel as a basis of their
classification.

The oesophagus conducts into a long, coiled, intestinal canal, which is
surrounded by a large liver, the kidneys, and numerous glands. The intestine
ends in an anal opening placed anteriorly. The heart, as a rule, has one
auricle (Monotocardia), more rarely two (Diotocanlia), and serves as a central
organ for the supply of a much branched system of blood-vessels. When the
gills or lungs are placed in front of the heart (Prosobranchia, Pulmonata), the
auricles are anterior to the ventricle ; but when placed behind the heart
(Opisthobranchia, Pteropoda), the auricle is posterior.

Only a few Gastropods breathe through the general surface of the body,
and are without distinct organs of respiration ; the vast majority possess gills
or lungs. The gills are lamellar or tuft-like, sometimes branched or feathered
lobes of the integument, and are usually placed in the gill-cavity below the
mantle ; more rarely they project freely on the back or at the sides. Only
exceptionally are they present in large numbers and symmetrically developed ;
and when so disposed they are always secondary structures not homologous
with the normal ctenidia. Typically there are two gills, but the left usually
becomes completely atrophied, and the right takes up a median position, con-
sequent upon the torsion of the body, or even migrates over to the left side.
Air-breathing snails have the gills replaced by a sac-like cavity, the lung
occupying the place of the gill-cavity. The walls of this respiratory cavity
are covered with a finely branched network of blood-vessels. The Amj'"!-
lariidae and Siphonariidae possess both gills and lungs. The opening of the
respiratory cavity is reduced to a round or crescentic aperture, called the

438 MOLLUSCA . SUB-KINGDOM vi

breathing pore. The sides of this pore, in operculated snails, are often pro-
duced outwards, so as to form a closed or cleft tube, corresponding with which
there is frequently a canal-like process of the shell.

Gastropods are remarkable for their extreme differentiation of the repro-
ductive organs. The sexes are distinct in the Prosobranchia and Heteropoda,
but united in the Opisthobranchiata, Pteropoda, and Pulmonata. The ovarian
and seminal ducts of hermaphrodites sometimes open into a common cloaca,
or they may terminate in separate openings.

The shell, as has already been remarked, is secreted by the mantle, and is
limited in form and size by the configuration of the intestinal sac. It is
composed of a chitinous substance (concliiolin) infiltrated with lime carbonate,
or exceptionally with sulphate of lime in small quantities. Shell characters
are of great importance in distinguishing genera and species, but their value
in classifying larger groups is comparatively slight, owing to the fact that,
very similar shells are often developed among forms which differ widely in
their general organisation. Two forms of shell-habit occur, the symmetrical
and the spiral. The first are flat-, conical, or saucer-shaped, and characterise
only a few groups (Cyclobranchia, Aspidobranchia, Pulmonata). Transition
forms between the symmetrical and spiral are to be observed in conical shells
with slightly inrolled beaks. Exceptional forms of the spiral shell are seen
in FermetuSj which is irregularly coiled, and in Planorbis, Bellerophon, and
Atlanta, coiled in one plane (discoidal). Usually the shell forms a screw-like
spiral, and rests upon the back of the creature in such a way that the apex is
directed upward and backward, the aperture forward and downward. Holding
the shell upright so that the apex is above, and the aperture below, facing
the observer, it is said to be right-handed or dextral when the opening is on
the right side, and left-handed or sinistral when on the left side. By far the
larger number of Gastropods are dextral ; but a few (Clausilia, Physa, Spirialis)
are normally sinistral. Eight-handed individuals of normally left-handed
genera, as well as pathologic individuals of normally right-handed forms, are
occasionally met with.

In drawing and describing Gastropod shells, the apex is ordinarily directed
upward, so that the right- ,or left-handedness may be seen at a glance. It is
also customary to employ the terms above and below in the same sense as
posterior and anterior. The height or length of the shell is measured by a
line drawn from the apex to the lower margin of the aperture.

The shell is to be considered as a more or less rapidly widening cone,
which is wound either around an axial pillar, called the columetta, or about a
central tubular cavity. Each coil of the tube is termed a whorl, and all the
whorls except the last one form together the spire. The last or body whorl
is often very much larger than the preceding ; its lower, sometimes flattened
surface is called the base. As a rule, the whorls are in contact with each
other, each in succession either partly or entirely covering the preceding ; but
in rare cases they form a loose spiral, in which the whorls are separated from
one another. The spire is said to be convolute when the later whorls
entirely conceal the earlier ones, as in Cypraea. The line between two con-
tiguous whorls is known as the suture. According to the manner of inrolling,
various shell contours are produced, requiring numerous descriptive names,
such as conical, auriform, turbinate, fusiform, cylindrical, spherical, oval,
pyramidal, etc.

CLASS IV

GASTROPODA

139

Apex

When the inner parts of the whorls coalesce to form a columella, the shell
is said to be imperf orate ; it is perfwate when they do not so coalesce, but
leave a central tubular cavity instead. The opening of this perforation brlnw.
in the centre of the base, is designated the umbilicus (Nabel). A true
umbilicus reaches to the apex of the shell j when confined to the last whorl
only, it is called a false umbilicus. An umbilical fissure is sometimes pro-
duced through a partial covering of the umbilicus by the reflected inner lip,
or by a shelly growth termed the callu*.

The aperture is variable in form, being most commonly oval, roundrd.
crescentic, or half-round, but is sometimes contracted or even fissure-like. Its
margin is called the peristome, the outer part of which forms the outer lip. and
the part next the columella the inner lip. Some
shells have a continuous, uninterrupted peristome,
but as a rule the inner and outer lips are discon-
nected. The aperture is said to be entire when
rounded anteriorly (inferiorly), as in the Holo-
stomata ; it is channelled when a basal notch or
canal, caused by an inbending of the margin next
the base of the columella, is developed. This
anterior canal serves for the lodgment of the
siphon, as the tube is called which conducts water Sutu
to the gills ; it may be either straight or re-
curved, and in the Siphonostomata it is greatly
produced, sometimes even exceeding the aperture
in length. The outer lip may be entire or incised,
thin and sharp or thickened, curved outward (re-
flected) or inward (inflected), even or crenulated,
or it may be produced into alar or finger- like
processes. It is sometimes channelled by a canal
at the posterior border, in which the anal or ex-
current canal is placed. The upper or posterior
portion of the inner margin is commonly desig-
nated, especially in the Siphonostomata, as the true
inner lip, in contradistinction from the lower or
columellar portion. The inner lip is formed either
by the wall of the penultimate whorl, or by a

calcareous callus ; like the outer lip and columella, gawed thiough longitudinallj. shljwilli!
it may bear spiral folds, which in some cases columella with M'U.
extend backward as far as the apex (Fig. 794).

The external ornamentation usually consists of impressed lines or grooves,
or of elevated ridges, ribs, folds, nodes, spines, and the like. The markings
are called spiral when they run parallel with the suture, and frtmtm'se or
longitudinal when they meet the suture at right angles or obliquely. Many
Gastropods are brilliantly coloured, others have a velvety or hairy epidermis.
The fossilisation process is usually destructive not only of the epidermis, but
of the coloration as well.

The essential constituent of univalve shells is aragonite, which usually
forms a homogeneous, porcelain-like layer. Many families have in addition
to this an inner nacreous layer, which is made up of alternating strata «>f
conchiolin and calcium carbonate, running parallel with the inner surface of

Canal----

Fio. 7:>4.
[il, I. inn. Vii'\vfif sh'-ll

440 MOLLUSCA . SUB-KINGDOM vi

the shell. The porcellanous material is composed of three distinct layers,
each of which is made up of thin laminae, and the laminae in turn of very
small oblique prisms. The laminae of the middle layer are disposed at right
angles to those of the adjacent layers.

Many Gastropods have a calcareous or horny plate, called the operculum,
attached to the posterior part of the foot, and serving to close the aperture
more or less completely when the animal withdraws into its shell. Being
most commonly of corneous nature, it is seldom preserved fossil ; sometimes,
however, it is calcareous, and may attain considerable size and thickness. On
the outer surface it may be smooth, furrowed, granulated, or covered with
excrescences. The nucleus or initial point of growth is sometimes central, and
again eccentric or even marginal in position ; it may be surrounded by con-
centric markings, or form the origin of a spiral consisting of few (paucispiral)
or many (multispiral) whorls. Certain Solariidae have a conical operculum,
which is covered externally with numerous spiral lamellae.

The embryonic stages of Gastropods are completed in the egg. Very early
in its development the embryo forms a small shell, called the protoconch or
nucleus, which consists sometimes of several whorls, and not infrequently
differs in form from the shell of the adult. The protoconch remains attached
to the apex for a time, in the form of a small glistening knob, or a short
smooth spire, which occasionally stands at an angle to the rest of the shell, or
is even twisted in a contrary direction (heterostrophic). Should the protoconch
become decollated, a small calcareous plate closes over the apex of the spire.

All branchiate Gastropods are aqueous in habitat, but there are some
forms having a lung cavity which live permanently in fresh water (Limnaeidae),
and others which are exclusively marine (SipJwnariidae). The greater number
of Gastropods, especially the large and solid forms, frequent the coast-line,
and inhabit comparatively shallow water. Some become attached to shoals
and plants, others burrow in sand or mud. A great reduction in the Gastropod
fauna is noticed at a depth of between 70 and 100 meters, but many genera
(Pleurotoma, Fusus, Natica, Odostomia, Eulima, Scissurella, Turbo, Cylichna,
Tornatina, Actaeon, etc.) persist into the greatest depths yet explored. Most
marine Gastropods are killed by removal into fresh water; a few genera,
however, are able to maintain their existence in brackish or in fresh water
(Cerithium, Littorina, Eissoa, Trochus, Purpura, etc.). On the other hand, many
fresh-water forms (Melania, Melanopsis, Neritina, Ampullaria, Limnaea, Planorbis)
can survive in brackish or even strong salt water.

Most Gastropods are herbivorous, but a few subsist upon living or decom-
posed animal food. Many genera (Natica, Buccinum, Murex) perforate the
shells of other Mollusks with their radula, and extract the contents.

Classification. — Ordinal divisions have been based since the time of Cuvier
and Milne-Edwards upon the respiratory organs, and the structure of the foot
(whether adapted for swimming or crawling). The reproductive organs, and
the structure of the heart and nervous system, are also of prime importance.
For separating smaller groups, shell characters and the radula are largely
employed. Gastropods may be divided into two sub- classes : Streptoneura,
with the orders Ctenobranchiata and Aspidobranchia ; and Euthyneura, with
the orders Opisthobranchia and Pulmonata.

SDB-CLA>SI STREPTONEURA 441

Sub-Class 1. STREPTONEURA. Spengel.

(Prosobi'anchia, Cuvier; Cochlides, Ihering.)

Gastropods in which the visceral commissures are n-nw,/, {„•<„/, K-iuy an 8-sJi«j>«l
loop ; sexes separate ; heart behind the gill ; a shell almost always developed, and
with few exceptions provided with an operculum.

The Streptoneura, or Prosobranchiates as they are often called, constitute by
far the largest group of Gastropods, and comprise at least 20,000 living and
fossil species. The shell is usually spiral, more rarely symmetrical, saucer-
shaped or conical. The intestinal sac is twisted from left to right, so that
the anal opening is placed on the right side near the head, and the organs
normally belonging to the right side (kidneys and gills) migrate over to the
left. As a rule, only one (the right) of the lamellar gills is fully developed,
but in some cases the two are of equal size. The gill veins enter anteriorly
into the single or double-auricled heart.

The large number of Prosobranchiates have been variously classified.
Cuvier, Milne-Edwards, and most of the older zoologists laid emphasis upon
the number and formation of the gills ; Troschel and Loven upon the char-
acters of the radula ; Ihering upon the nervous system ; Morch and more
recently Perrier and Bouvier upon the structure of the heart. As none of
these characters leave a marked impress upon the shell, they are without
practical value in Palaeontology. Nevertheless, the two orders Aspidobranchia
and Ctenobranchia form natural groups, and are recognised, albeit under
different names, in all classificatory systems.

Order 1. ASPIDOBRANCHIA. Schweigger.

(Cyclobranchia and Scutibranchia, Cuvier.)

Nervous system not much concentrated anteriorly ; a penis generally absent ; radula
multiserial.

This group includes most Palaeozoic Gastropods, and is regarded as the most
primitive expression of the class. The nervous system and radula are of low, decidedly
generalised type, an-1 in ><>me families two symmetrical ctenidia or gills are developed,
as in Pelecypods.

Sub-Order A. DOCOGLOSSA. Troschel. Limpets.
(Cyclobranchia pars, Cuvier ; Heterocardia, Perrier.)

Symmetrical, ivith conic or bowl-shaped non-spiral shells ; operculum wanting. Organs
of respiration represented either by a ring of laminae (secondary or pallial gills) beneath
the mantle margin, or by a comb-shaped true gill in front, anterior to the heart, or by
both true and secondary gills. Tongue set with peculiarly modified teeth. Heart with
one auricle. Marine. Cambrian to Recent.

The impression of the adductor muscle in the shell cavity is horseshoe-shaped,
open in front. In the family Tryblidiidae, the horse-shoe is broken into numerous
separate impressions. The three families Patellidae, Acmaeidae, and Lepetidae have
the impression uninterrupted, and are distinguished by the structure of the gills. The

442

MOLLUSC A

SUB-KINGDOM VI

shells themselves exhibit little variation in form, and hence their generic and even
family affinities are almost always doubtful in the fossil state. About 1400 recent
limpets are known ; these are almost exclusively shallow water inhabitants, and sub-
sist on algae. Fossil forms are uncommon.

Family 1. Patellidae. Carpenter.

Patella, Linn. Cup-shaped, round, or oval, depressed conical, with sub-central or
eccentric apex. Surface usually with radiating ribs or striae. Silurian to Recent.

Helcion, Montf. Differs in having the beak strongly recurved
anteriorly. Eocene to Recent.

Helcioniscus, Dall ; Nacella, Schum. Recent.
Acmaea, Eschscholtz (Tectura, auct, Fig. 795). Like Patella,
but shell having generally a differentiated
marginal band inside ; externally smooth,
finely striated, or radially ribbed. Beak
anterior to the middle. Silurian to Recent.
Lottia, Gray, is closely allied.

Scurria, Gray (Fig. 796). High conical, smooth, with sub-
central beak. Jura to Recent.

Metoptoma, Phil. Depressed conical, with sub-central beak.
Posterior side excavated. Silurian to Carboniferous.
Lepetopsis, Whitf. Silurian to Carboniferous.
The genera Palaeacmaea, Hall, from the Silurian, and Scenella,
Billings, from the Cambrian, are the oldest representatives of the
Docoglossa. They are small, smooth, or radially ornamented, and
scarcely to be distinguished from Acmaea. Lepeta, Gray, and
Lepetella, Verrill, are small simple limpets of the Recent and
late Tertiary, with degenerate, aborted gills.

FIG. 795. '

Acmaea Raincourti,
Desh. Eocene ; Auvers,
near Paris.

nitida, Des-
.__„. Great Oolite;
Langrune, Calvados. l/i .

Family 2. Tryblidiidae. Pilsbry.

Limpets with the muscle scar broken into numerous separate impressions. Silurian.

Tryblidium, Lindstrom (Fig. 797). Shell depressed, very thick, oval, with anterior

beak ; ornamented externally with concentric
lamellae. Six pairs of muscle scars arranged
in the form of a horse-shoe. Silurian.

Sub-Order B. RHIPIDOGLOSSA.

Troschel.

(Scutibranchiata, Cuvier ; Zygobranchia,

Ihering; Diotocardia, Iheriiig.)
Symmetrical and limpet-like, or with spiral
shells. Gills plume-like, two and symmetrical,
or single. Eadula with several large plates or

teeth in the median portion, and excessively

TryUidium reticulatum, Lindstrom. Silurian; , ,7, 0-hfinp;i ninr

Gottiand. A, internal, and B, external aspect numerous, crowded, narrow, hook-shapea -
(after Lindstrom). \]

ginai ted^ Qperculum often present.

rrv' The Rhipidoglossa comprise both air-breathing and aquatic forms, and are divisible
into two series: Zygobranchia, in which two gills are developed, and the shell is
generally perforated at the apex or has a slit in the outer lip ; and Anisobranchia,
with a single gill and generally unslit shell.

SUB-ORDER B

RHIPIDOfJLOSSA

Family 1. Haliotidae. Fleming.

Shell flattened, auriform, with wide aperture, and no operculum. Interior nacreous,
a row of perforations on the left outer margin. Marine. Cretaceous to Recent.

Haliotis, Linn. This, the solitary genus, occurs very rarely !'<>— il rxivpt in tli--
Quaternary. .

Family 2, Pleurotomariidae. d'Orbigny.

Shell spiral, sub-spherical, turbinate, conic, turreted, or planorboid, nacreous inter-
nally. Outer lip with a slit, from which a slit-band (the anal fasciole) extends bd>
traversing all the whorls. The slit sometimes replaced by one or more perforations.
Operculum horny. Cambrian to Recent.

Eaphistoma, Hall. Spire depressed or completely flattened ; whorls angular
above. Umbilicus moderately broad ;
outer lip with short notch on the keel.
Cambrian to Silurian.

Pleurotomaria,
Defr. (Figs. 798-
802). Shell
broadly conical or
turbinate ; spire

FIG. 798.
Pleurotomaria (Rhaphisto-

Pleurotomaria
Lias ; Goppingen,

FIG. 79P.

i in) polita, Goldf.
nrtemberg.

Lower

Sometimes high,

in other cases de-

pressed ; umbili-

cus present or absent. Outer lip with slit ; growth-lines strongly recurved, meeting

in the slit-band. Silurian to Recent. Four living and several hundred fossil species

known. Rare in the late Tertiary

Sub-genera : Ptydiomphalus, Agassiz ; Mourlonia, Worthenia, Agnesia, de Koninck ;
Gosseletina, Ivania (Baylea, de Kon.), Bayle ; Ecqyhistomella (Fig. 798), Zij'jit'*. L«nl,ll,i.

Fio. 800.

Pleurotomaria Iritorquata, Des-
longchainps. Middle Lias ; May,
Calvados.

rieurotomfirin
Lower Oolite ; Bayeux, Calvados. 1/2-

Stuorella, Schizodiscus, Kittl ; Brilonella, Kayser ; Hesperiella, Holzapfel ; Cnjptnenia (Fig.
799), Leptomaria, Deslongchamps (Fig. 802), etc.

Porcellia, Leveill^ (Leveilleia, Newton), (Fig. 803). Shell discoidal, Hat, widely
umbilicate, nearly symmetrical, and all but the first few whorls coiled in the same

444

MOLLUSGA

SUB-KINGDOM VI

plane. Outer lip sharp, with long slit. Slit-band prominent, traversing the central
portion of the whorls. Devonian and Carboniferous.

Kokenella, Kittl. Very flat, discoidal, and only slightly asymmetrical, with a

broad slit -band. Trias.
K. Fischeri, Hoernes sp.
Polytremaria, de
Kon. Shell turbinate,

FIG. 802.

Pleurotomaria (Leptomaria) macromphala, Zittel. Tithonian ; Stram-
berg, Moravia.

FIG. 803.

Porcellia Puzosi, Leveille. Car-
boniferous ; Tournay, Belgium.

with band replaced by a row of perforations, of which the posterior ones are succes-
sively closed. Carboniferous.

JDitremaria, d'Orb. (Fig. 804). Two oval perforations connected by a slit are
present behind the outer lip ; base with an umbilical callus. Jura.

Trochotoma, Deslongch. Shell turbinate, with conical base. A slit closed at
either end is present behind the outer lip,
and corresponding to it is a slit -band.
Trias and Jura.

Schizogonium, Koken ; Temnotropis,
Laube. Trias. Gantantostoma, Sandb.
Devonian.

FIG. 804.

Ditremnria gmnulifera, Zittel. Upper Tithon-
ian ; Stramberg, Moravia.

FIG. 805.

A, Murchisonia Ulineata, d'Arch. and
Vern. Devonian ; Paffrath, near Cologne.
£, M. Blumi, Klipstein. Trias ; St. Cassian,
Tyrol. C, M. subsukata, de Kon. Carbon-
iferous ; Tournay, Belgium. Last two
whorls, 2/lt

Murchisonia, d'Arch. and Vern. (Fig. 805). Shell turreted, with numerous smooth
or ornamented whorls. Outer lip with a slit, and corresponding to it a slit-band.
Cambrian to Trias. Maximum distribution in Devonian and Carboniferous.

Sub-genera : Hormotoma, Salter ; LopTiospira, Whitf. ; Goniostropha, Oehlert ; Cheilotoma,
Koken.

Family 3. Bellerophontidae. M'Coy.

Shell bilaterally symmetrical, coiled in one plane, usually quite thick, with iveakly
developed nacreous layer. Aperture broad, oval, or narrowly elongate. Outer lip with a
notch or slit in the middle, corresponding to which is often a band or row of perforations
along the whorls. Cambrian to Trias.

The Bellerophontidae were classed by Montfort with the Cephalopoda, by Deshayes,
on account of their resemblance to Atlanta, with the Heteropoda, and by de Koninck
with the Aspidobranchiates. The thick shells sometimes retain traces of their
original pigmentation. At least 300 Palaeozoic species have been described.

SUB-ORDER B

RHIPIDOQLOSS4

Bellerophon, Montf. (IVaagenia, <!.- K-.n.), (Fig. 806). Slu-11 j:lol....-.- i,r «li-.-«.i«lal.
more or less convolute, and narrowly umbilicatf on both sides. Aj..-i-tiiiv Mil.-i-iirular

or oval, with a dri-p iii.-<liaii
^inii- ; .>lit-liaii<l cith.-i <li~-
tinct or r.-plarnl 1,\- a k.-i-l,
sometimes absent. Outer

Fio. 806.

Bellerophon bicarenus, Leveille. Carboniferous ; Tournay,
Belgium.

s07.

Klein. Curb"1
burg.

FIG. 808.
Cyrtolites ornatus, Conrad. A , Speci-

lip sharp, columellar edge often with callus. External surface marked only l>y

growth- lines. Silurian to Permian; muximum in
Carboniferous.

Sub-genera: Bucania, Hall. Silurian ami Devonian.
Warthia, Mogulia, Waagen. Carboniferous

Euphemus, M'Coy (Fig. 807). Like Bellerophon,

but the inner whorls, and a part of the last, spirally
striated. Carboniferous.

Salpingostoma, Roem. Shell widely umbilicate,
the aperture suddenly becoming greatly dilated.

men viewed from one side, from o'rdo- Whorls traversed along the middle by a slit closed
viclan of Boonville, New York (after . . , , • i a-i • j T»

F.Roemer). B, Anterior aspect of speci- anteriorly and posteriorly. Silurian and Devonian.

ohiofr°m Ordovician of Cincinnati' Trematpnotus, Hall. Like the last, but tin- .-lit-

band replaced by a row of perforations. Silurian.

Cyrtolites, Conrad (Fig. 808). Shell widely umbilicate, keeled, with- nit >lit, and
with strong transverse ribs. Cambrian to Carboniferous.

Family 4. Fissurellidae. Risso.

Shell symmetrical, cap- or limpet-shaped, non-nacreous, without operculnm. Apex erect
or pointing backward, often recurved, perforated. Anterior margin often with a fissure :
young shell with a spiral nucleus. Marine; shore forms. Carboniferous to Re».vnt.

Of the three sub-families into which this group is divided, the Fissun ///;/"• an
known only in the recent fauna, Fissurellidinae occur in the Pliocene ;
all the earlier forms are Emarginulinae.

Fissurella, Brug. Shell conical, oval, with an oval apical orifice
bounded inside by an entire callus. Recent. The numerous fossil
species referred to this genus belong to Fissuridea.

Fissurellidea, d'Orb. ; Pupillaea, Gray ; Megatebennus, Lucapiv //",
Pilsbry ; Macroschisma, Swains. These are all recent genera, with
the apical orifice very large.

Lucapina, Gray. Like Fissurella, but with large apical orifice
and finely crenate periphery. Pliocene and Recent.

Fissuridea, Swains. (Glyphis, Cpr. ; Fissurella, auct), (Fig. 809).
Shell conical, oval, with apex in advance of the middle, giving place
to a perforation which is bounded inside by a posteriorly truncate callus.
iferous (?) to Recent ; very abundant in the Tertiary.

Pro. BOO.

I

Bfr. Miucfiit-;
. Hungary.

Carbon-

446

MOLLUSCA

SUB-KINGDOM VI

Puncturella, Lowe. Shell conical, with a perforation at or in front of the post-
median apex, behind which there is a shelf within the cavity. Eocene to Kecent.

FIG. 810.

Emarginula Schlotheimi,
Bronn. Oligocene ; Wein-
heim, near Alzey, Baden.

FIG. 811.

Emarginula Muensteri, Pictet.
Keuper; St. Cassian, Tyrol.
A, B, Natural size. C, Enlarged.

FIG. 812.

Rimula Goldfussi,
Roemer sp. Coral-Rag ;
Hoheneggelsen, Hanover.
A, Natural size. B, En-
larged.

Emarginula, Lam. (Figs. 810, 811). Conical or cap-shaped, with, persistent post-
median apex, and a slit in the front margin of the shell. Surface cancellated.
Carboniferous to Eecent.

Rimula, Defr. (Fig. 812). Like the last, but slit replaced by a closed hole on the
anterior slope. Lias to Recent.

Subemarginula, Blainv. Like Emarginula, but slit short or wanting, and no slit-
band. Eocene to Recent.

Scutus, Montf. (Parmophorus, Blainv.). Shell depressed, oblong, without fissure,
slit, or slit-band ; muscle impression near the edge. Eocene to Recent.

The families Phenacolepadidae, with the single genus Phenacolepas, Pils. (Scutellina,
Gray), Cocculinidae, and Addisoniidae are recent groups allied to the Fissurellidae.

Family 5. Euomphalidae. de Koninck.

Shell depressed conical to discoidal, spirally coiled, more or less deeply and widely
umbilicate. Whorls sometimes in a loose spiral, smooth or angular ; the earlier whorls
frequently separated off by partitions. Outer lip usually with a shallow indentation.
Operculum calcareous. Cambrian to Cretaceous.

The Euomphalidae belong primarily to the Palaeozoic era. They have been
variously associated with the Trochidae, Turbinidae, Littorinidae, and Solariidae. The
shells bear a strong resemblance to those of the last-named group, but in Solarium the
embryonic apex is sinistral, whereas in the Euomphalidae it is dextral. Opercula are
known with certainty in only a few genera, such as Maclurea. de Koninck surmised

that the deeply excavated, slipper-shaped opercula from
the Carboniferous, described originally as Calceola
Dumontiana, are referable to Euomphalus.

Straparollina, Billings. Cambrian. Ophileta, Van-
uxem. Cambrian to Silurian. Maclurea, Leseueur.
Ordovician and Silurian.

Platyschisma, M'Coy. Thin - shelled, depressed
conical, smooth. Umbilicus relatively narrow ; outer
lip with broad sinus. Silurian to Carboniferous. P.
helicoides, Sow. Carboniferous.

Straparollus, Montf. (Fig. 813). Turbinate to dis-
Whorls smooth or with fine transverse striae. Silurian
to Jura ; especially abundant in Devonian and Carboniferous.

Phanerotinus, Sow. Like the last, except that the whorls form an open spiral.
Carboniferous.

Euomphalus, Sow. (Pleuronotus, Hall; Schizostoma, Bronn), (Fig. 814).

FIG. 813.

Straparollus Dionysii, Montf. Car-
boniferous ; Vise, Belgium.

coidal, with broad umbilicus.

SUB-ORDER B

RHIPIDOGLOSSA

447

conical to discoidnl, with wide umbilicus. Spin- fl;itt«-n«-d or <-vni concave superiorly;
whorls angular, the edges sometimes set with nodes (Phymatifer, de Kon.). Outer li]>
with emargination at tlie upper angle. Silurian to Tria- : maximum in Carbonift-rou.-.

FIG. 814.

I'liKiiHiiliitlti* : rut Hint, Sowb. sp. Carboniferous ; Kildare, Ireland. Discohelix orbis, Reuss. Middle Liaa;

A, Superior, and B, Inferior aspect. Hinter-Schafberg, Austria.

Sub-genera : Omphalocirrus, de Ryckholt. Devonian and Carboniferous. Coelocentrm,
Zittel. Trias.

Discohelix, Dunk. (Fig. 8 1 5). Flat, discoidal ; upper side flat or slightly concave, the
lower widely umbilicate. Whorls rectangular, with sharp edges. Trias to Oligocene.

Family 6. Stomatiidae. Gray.

Shell depressed, composed of a few very rapidly widening whorls ; nacreous internally;
aperture large.

With the exception of Stomatia, Helb., and Stomatella, Lamarck, a few rare
representatives of which are known as early as the Cretaceous (perhaps also Jurassic),
this family belongs to the Recent period.

Family 7. Turbinidae. Adams.

Shell turbinate, discoidal, or turreted, nacreous internally. Aperture rounded or
oral ; inner lip smooth or with callus, the outer lip never reflected.
Operculum calcareous, very thick, convex externally. Ordovician
to Recent.

The extraordinarily abundant recent Turbinidae are dis-
tinguished principally by
characters of the operculum ;
but inasmuch as this is
known in but few of the
fossil forms, the precise
determination of the latter
is usually uncertain. It is

customary, therefore, to

j , OmptaZotroeMu discus, Sowb. Silurian preserved in place (after

group under the general Dudley, England. Vi (after Nicholson). Lindstrom).

head of Turbo such fossil

turbinate shells with a sub-circular aperture as are not specially distinguished by some
other characters.

Omphalotrochus, Meek (Polytropis, de Kon. ; Oriostoma, Lindstrom non Munier-
Chalm.), (Figs. 816, 817). Discoidal or depressed conical, widely umbilicate. Whorls

Fio. 817.

n,ntihit lot rochus globosiis,
Sehloth. sp. Silurian ;
Gottland. Opt-it-ulnm

448

MOLLUSCA

SUB-KINGDOM VI

round, ornamented with raised longitudinal keels. Operculum extremely thick, flat
internally, conical externally, multispiral. Ordovician to Carboniferous; especially
abundant in Silurian.

Cyclonema, Hall (Fig. 818). Turbinate ; whorls inflated and ornamented with

FIG. 818.

Cyclonttnci bilix,
Conrad. Ordo-
vician ; Cincinnati,
Ohio.

FIG. 819.

Astmlium(Bolma)rugomm, Linn. Pliocene;
Plena, Tuscany. Shell and opereulum.

FIG. 820.

Astralium, (U vanilla) Damon,
Laube. Keuper ; St. Cassian,
Tyrol.

fine spiral striae. Aperture rounded, peristome discontinuous. Operculum conical,
flat internally, externally with spiral flutiiigs. Ordovician to Devonian.

Astralium, Link. (Figs. 819, 820). Turbinate; whorls
rough, often spinose, and usually keeled. Aperture depressed,
with disconnected margin. Base more or less flattened ;
opereulum calcareous, thick, flat internally,
spirally coiled, and with very eccentric
nucleus. Trias to Recent.

Sub-genera : JBolma, Risso (Fig. 819) ; Pachy-
poma, Lithopoma, Uvanilla (Fig. 820), Guil-
fordia, Gray ; Calcar, Montfort, etc.

FIG. 821.

Turbo (Ninella) Parkinsoni,
Bast. Oligocene ; Dax, near
Bordeaux.

FIG. 822.

Collonia modesta,
Fuchs. Oligocene ;

Turbo, Linn. (Fig. 821).

.

Monte Grumi, near conical ; aperture nearly circular.
Castel Gomberto,

Turbinate to
Oper-

flat internally, extern-
ally convex, multispiral, with sub -central nucleus. Silurian (?)
to Recent.

Sub -genera : Sarmaticits, Ninella (Fig. 821) ; Modelia, Callopoma,
Gray ; Senectus, Humphr. ; Batillus, Schum., etc.

Collonia, Gray (Fig. 822). Like Turbo, but opereulum with
thin calcareous layer disposed in a spiral rib. Eocene to Recent.

Family 8. Phasianellidae. Troschel.

Shell elongated, oval, thin, smooth, lustrous, porcellanous, not
nacreous internally, without umbilicus. Body whorl large, with
oval aperture. Operculum calcareous, convex externally. Devonian
to Recent.

FiG. 823.

Phosianella Gosauica,
Zekeli. Turoniau ;
Gosati, Austria.

Phasianella, Lam. (Phasianus, Montf.), (Fig. 823). With
the characters of the family. Cretaceous to Recent ; perhaps also Palaeozoic.

SUJ-OKDKH

RHIPIDOGLOS&A

449

Family 1). Delphinulidae.

Shell turbinate or discoitlxl, HxnnUij ////••/-, nacrwtU /'/</»r/«f////, ///«/ ornamented
• .'•(• nnilly with spines, ribs, or folds. Aperture circular, peristome entire; outer lip"
usually expanded or thickened. Operculum horny, often strengthened by a thin calcareous
outer layer. Silurian in Recent.

Graspedostoma, Lindstrom. Globose, narrowly umbilical.-, with .-hurt -pin-, and
large transversely striated or cancellated body whorl. Inner liji with an alar process
at the end of the columella. Silurian. C. elegantulum, Lind>tr<>m.

Crossostoma, Morr. and Lye. (Fig. 824). Depressed turbinate, smooth, without

FIG. 824.

,'/.

sp.
Ma

re-

thru in, d'Orb.
.Middle Lias;
y, Calvados.

FIG. 825.

Liotia Gervillei,
IH>sh. sp. Calcaire
Grossier ; Haute-
ville, near Valogne,
France.

FIG. 826.

I>ill>liinula segregate,
Heb. Desl. Callovian ;
Montreuil - Bellay,
Maine-et-Loire.

FIG. 827.

Delphinula tc<

Hion-t. sp. Oligocene

Gaas, near Dax, France.

umbilicus. Spire short, aperture round, narrowed by a callus. Outer lip somewhat
reflexed. Trias and Jura.

Liotia, Gray (Fig. 825). Depressed turbinate, with transverse swellings. Aperture
thickened by a callous rim. Jura to Recent.

Delphinula, Lam. (Angaria, Bolt.), (Figs. 826, 827). Depressed turbinate, um-
bilicate. "Whorls scaly, spinous, or spirally ornamented. Aperture circular, lip
without thickening. Trias to Recent.

Family 10. Trochonematidae. Zittel.

Shell pyramidal, turbinate, or discoidal, dextral or sinistral, with internal nacreous
layer. IVTiorls convex, with one or more longitudinal keels, and sliijlitltj undulating trans-
verse striae or ribs. Aperture rounded, sometimes
with faint notch. Operculum unknown, presumably
horny. Marine. Cambrian to Cretaceous.

This extinct group is very abundant in the
Palaeozoic, and notably so in Jurassic rocks. The
shells, as a rule, are highly ornamented, and have
been associated by some with the Littorinidae, by
others with the Turbinidae or Purpurinidae. They
form a distinct family, which is best placed in tl it-
neighbourhood of the Turbinidae and Trochidae.

Trochonema, Salter. Pyramidal to turbinate,
deeply umbilicate, longitudinally keeled and trans-
versely striated. Aperture round ; the umbilicus
surrounded by a keel. Cambrian to Silurian.

Eunema, Salter (Fig. 828). Pyramidal, with Canada,
acute, elongate spire, and no umbilicus. "Whorls
with two or more spiral keels, and strong transverse striae,
notched anteriorly. Ordovician to Devonian.

Amberleya, Morr. and Lye. (Eucyclus, Deslongch.), (Fig. 829). Turbinate to
VOL. I 2 G

Fio. 828.

Eunema strigi-
Or-

Amberleya capitanea,
Miinst. Upper Liaa ;
La Verpilliere, near
Lyons, France.

Aperture oval, slightly

450

MOLLUSCA

SUB-KINGDOM VI

pyramidal, with deep sutures, and no umbilicus. Spiral keels usually nodose or spiny,
and crossed by strong transverse striae, which are more numerous in the lower portion

FIG.

Platyacra impressa,
Schafh. sp. Lower
Lias; Hochfelleri,
Bavaria.

FIG. 831.
Cirrus nodosus, Sowb. Lower Oolite ; Yeovil, England.

of the whorls than in the upper. Aperture rounded, sometimes with a shallow notch.
Trias to Cretaceous ; common in all divisions of the Jura.

Oncospira, Zitt. Pyramidal, spirally ribbed, with one or two transverse swellings
on each whorl, disposed continuously along the spire. Jura.

Hamusina, Gemm. Sinistral, with nodose longitudinal keels, and no umbilicus.
Lias.

Platyacra, v. Ammon (Fig. 830). Like the last, but with flattened apex, and the
earlier whorls discoidal. Lias.

Cirrus, Sow. (Scaevola, Gemm.), (Fig. 831). Sinistral, turbinate shells, deeply
and widely umbilicate. Spire acuminate ; whorls spirally keeled and striated, and
with strong transverse ribs. Trias to Middle Jura.

Family 11. Trochidae. Adams.

Shell conical, turbinate or pyramidal, nacreous internally. Aperture trapezoidal or
sub-circular, peristome disconnected, inner lip often bearing a tooth. Base more or less
flattened; operculum thin, horny. Ordovician to Eecent.

Precise determination of the numerous fossil Trochidae is not less difficult than
that of the Turbinidae. Palaeozoic and Mesozoic forms in many cases do not har-
monise with recent genera, but represent
rather collective types, in which characters
now distributed amongst several genera or even
families are united. Shells incapable of more
accurate determination are commonly assigned
to the genus Trochus. Among the more
ancient true Trochidae may be mentioned the
following : — the Trochus species described by
Lindstrom from the Silurian of Gotland ; also
Flemingia and Glyptobasis, de Koninck, and
Microdoma, Meek and Wort-hen, from the
Carboniferous; Turbina (Fig. 832) and Tur-
bonellina, de Koninck, ranging from the Car-
boniferous to the Trias.
Shell conical or pyramidal ; whorls slightly convex or

Fio. 832.

Turbina spiralis,
Miinst. Keuper ; St.
Cassian, Tyrol.

FIG. 833.

Trochus (Tectus) Luca-
sanus, Brongt. Oligo-
cene ; Castel Goinberto,
near Vicenza.

Trochus, Linn. (Fig. 833).

RHIPIDOGLOSSA -i:.l

iiiiin lip often truncated anteriorly, thickened or

Sub-genera : Tectus, Montf. (Fig. 833) ; Polydonta, Schum. ; Clanculus, Montf., etc.

SUB-ORDER B

flat; base angular at p.-riplu-ry.
with Un-tli. Silurian to

FK..

nodosa, Miinst.
Keuper ; St. Cassian, Tyrol.

Fi...

Minimi, ,,!(<!. (Oj'lixtl'll-) /Xltulll,

Brocchi. Miocene ; Steina-
bninn, near Vienna.

Fn,. 886.

<l!iii>nla picta,
Eichw. Min-
cene ; Wiesen,

near Vienna.

Fi...

<;i i'i> nl« BroccJi li,
Mayer. Pliocene;
Montopoli, Tuscany.

Monodonta, Lam. (Figs. 834, 835). Turbinate, with nearly round aperture, the

FIG. 838.

Ccdliostoma semi-
punctatum, Miinst.
Keuper ; St. Cas-
sian, Tyrol. 2/j.

Solariella peregrinn,
Libassi sp. Pliocene ; Or-
ciano, Tuscany.

FIG. 839.

Calliostoma oc<///"//s.
Buv. Coral-Rag ; St.
Michiel, Meuae.

Fm. 840.

Lewisiella conica, d'Orb.
sp. Middle Lias; M;:y,
Calvados.

Fi.:. 84-2.

rita margaritnln.
Mer. Oligocene; Weinheim.
near Alzey, Baden.

columella ending below in a tooth. Trias to Recent.
Oxystele, Phil., the tooth is wanting.

Gibbula, Risso (Figs. 836, 837). Turbinate or low
conic, umbilicate, and with rounded aperture. Tertiary
and Recent.

Calliostoma^ Swains. (Ziziphinus, Gray), (Figs. 838,
839). Conical, with peripheral keel and flattened base.
Trias to Recent.

Other genera are Cantharidus, Montfort ; Lewisiella,
Stol. (Fig. 840) ; Chlorostoma, Swains. ; Solariella,
Wood (Fig. 841); Margarita, Leach (Fig. 842);
Danilia, Brus. (Fig. 843), etc. Most of these have a
more or less extensive Tertiary history.

In the sub-genera Osilidus and

Fie. 843.
dntlirntn, Etall. sp. Coral-

R:i- : Valtin, Ain. 2/1-

Family 12. Umboniidae. Adams.

Shell small, usually depressed discoidal, smooth and lustrous, or with fine spiral
striae, and without nacreous layer. Outer lip sharp, peristome discontinuous. Umbilicus
often concealed by a callus; operculum horny. Silurian to Recent.

Allied to the recent genera Umbonium, Link. (Rotella, Lam.), Isanda, Adam>,
Camitia, Gray, etc., are a number of fossil forms, such as Pycnomphalus, Lindstrom,
from the Silurian and Devonian ; Anomphalus, Meek and Worthen, and Rotellina, de

452

MOLLUSC*

SUB-KINGDOM VI

Koninck, from the Carboniferous ; Chrysostoma, Swainson (Fig. 844), from the Jura, and
others, which are probably the ancestors of the Umbonidae.

Whether the genera Teinostoma (Fig. 845) and Vitrinella, Adams, together with
their fossil allies from the Carboniferous onward, are rightly assigned to this group, is

FIG. 844.

Cli r</sostoma
Acmon, d'Orb.
sp. Middle
Jura ; Balin,
near Cracow.

FIG. 845.

Teinosloma rotellae-
formis, Desh. Calcaire
Grossier ; Grignon,
near Paris.

FIG. 846.

Helicoeryptus pusillus, Roein. sp.
Coral - Rag ; Lindeuer Berg, near
Hannover.

FIG. 847.

Adeorbis
Desh.
Meeressand)
Seine-et-Oise

tricostatus,
(Middle
Auvers,

doubtful. Helicocryptus, d'Orb. (Fig. 846), from the Jura and Cretaceous, is related to
Vitrinella. Cyclostrema, Marryat, comprising small, lustrous shells ; and the spirally
striated ones known as Adeorbis, S. Wood. (Fig. 847), present strong resemblances to the
Umboniidae ; but, according to Fischer, they form separate families. Both of the last-
named genera have fossil representatives in the Tertiary.

Family 13. Neritopsidae. Fischer.

Shell oval to semi-globose, with short, sometimes laterally twisted spire, and without

umbilicus or nacreous layer. Body whorl very large; aperture oval or semi-circular.

Inner lip callous, curved, and occasionally notched. Operculum calcar-

%eous, not spiral, with sub-central nucleus, and internally with callous
columellar margin, which forms a broad, angular, or rounded process
in the middle. Devonian to Recent.

The Neritopsidae are distinguished from the closely related
Neritidae, principally by the totally different, non-spiral operculum,
and by the fact that the earlier whorls are not resorbed, as in the
Keuper ; St. Cassiaii. latter family. Detached opercula have been described under the

names of Peltarion, Scaphanidia, Cyclidia, and Rhynchidia.
Naticopsis, M'Coy (Neritomopsis, Waagen), (Figs. 848-850). Shell oval to globose,

FIG. 848.

Naticopsis Mandel-
slohi, Klipst. sp.

Fio. 849.

A, Naticopsis ampliata, Ph,l. Carboniferous ; Vise, Belgium.
Ji, Operculum of N. pianispira, from same locality (after de
Koninck).

FIG. 850.

Naticopsis lemniscata, Hoernes. Trias ;
Esino, Lombardy. Original coloration
preserved.

smooth or transversely striated. Aperture oval ; inner lip flattened, somewhat

SUB-ORDER B

RHIPIDOGLOSSA

453

callous, curved, and sometimes transversely striated. Sparse in Devonian, but v.-rv
common in Carboniferous and Trias,

Hologyra, Koken. Semi-globose, smooth, with faintly impressed sutures. Sj.ii«
short, laterally situated, not resorbed internally. Inner lip flattened, callous, covering
the umbilicus, and with sharp margin. Abundant in the Trias. Some species, such
as H. neritacea, Miinst. sp., have the original colouring admirably preserved.

Marmolatella, Kittl. Auriform to cap-shaped, with very short, incurved, and
almost marginal spire. Last whorl much distended ; inner lip callous, broad, arched.
Trias. M. (Ostrea) stomatia, Stopp. sp. ; M. Telleri, Kittl. sp.

Natiria, de Koninck ; Silurian to Carboniferous. Palaeonarica, Kittl. (Pseudo-
fossarus, Koken).

Naticella, Miinst, (Fig. 851). Thin-shelled, depressed, with straight spire, and
large, transversely ribljed body whorl. Trias.

Platychilina, Koken (Fossariopsis, Laube). Spire depressed, straight ; last whorl

Southern Tyrol.

FIG. 852.

A, Neritopsis moniliformis, Grat.
' - ' ' B,N.

Montre'uil-Beliay, Maine-et-Loire.

FIG. 851.

Naticella costata, Miinst. Miocene ; Lapugy, TransylvanL. _, _..
Upper Trias; Wengen, spinosa, Heb. Deslong. Callovian ;

FIG. 853.

Neritopsis radula. Recent ;
New Caledonia. A, External,
and B, internal aspect (after
Crosse). 1/1-

large, surface rough, tuberculose. Inner lip even, with simple margin. Trias. P.
pustulosus, Miinst. sp.

Delphinulopsis, Laube. Like the last, but spire composed of loosely connected
whorls. Sutures deep. Body whorl with nodose longitudinal keels. Inner lip even,
with sharp margin. Trias. D. binodosa, Miinst. sp.

Neritopsis, Grat. (Figs. 852, 853). Spire depressed, body whorl very large. Sur-
face with spiral and transverse ribs or nodes, often cancellated. Inner lip thickened,
with broad, angular emargination in the middle. Trias to Recent.

Family 14. Neritidae. Lamarck.

Shell semi-globose, without umbilicus or nacreous layer. Spire very short, somewhat
lateral ; whorls rapidly broadening, the last very large, and earlier ones resorbed inter-
nally. Aperture semi-circular ; margin of the flattened or calloused inner lip often with
teeth. Operculum calcareous, with a lateral spiral nucleus, and a process for muscle
attachment on the inner side. Trias to Recent.

The Neritidae are partly marine, and partly fresh-water inhabitants. The former
live usually in the vicinity of the coast, the latter often in brackish water. Since the
earlier whorls are internally resorbed, casts reveal no trace of the spire. This
character, together with the form of the operculum, serves to distinguish the
family from the Naticopsidae, from which both it and the terrestrial Helicinidae
are probably descended. Fossil forms not infrequently retain traces of their former
coloration.

Neritaria, Koken (Protonerita, Kittl). Spire acuminate, suture deep, surface
smooth. Outer lip sharp ; inner lip callous, flattened. Resorption of the inner walls
incomplete. Trias.

454

MOLLUSCi

HUB-KINGDOM VI

Nerita, Linn. (Fig. 854). Thick, ovoid, or semi-globose, imperf orate. Surface
smooth or with spiral ribs. Inner lip callous, flattened, with a straight, often den-
ticulate border. Operculum sub-spiral. Trias (?) to Recent.

Oncochilus, Petho (Fig. 855). Smooth ; inner lip arched, callous, bearing two or
three teeth on the margin or smooth ; outer lip sharp. Trias and Jura.

Lissochilus, Petho (Fig. 856) ; Neritodomus, Morr. and Lye. ; Neritoma, Morris,
Jura. Otostoma, d'Arch. ; Dejanira, Stol. Cretaceous.

Velates, Montf. (Fig. 857). Depressed conical, only the curved apex of the spire

FIG. 854.

A, Neriia Laffoni, Merian. Citharella Limestone ; Epfen-
hofen, near Schaffhausen, Switzerland. B, N. granulosa,
Desh. Eocene (Sables Moyens) ; Auvers, near Paris.
(', Operculum of a recent Nerita.

Oncochilus chromaticus, Zittel. Upper
Tithonian ; Stramberg, Moravia.

visible. Last whorl very large. Inner lip convex or straight, with denticulate margin.
Abundant in the European Eocene; sometimes attaining a size of 10 or 12 cm.

Neritina, Lam. (Fig. 858). Small, semi-globose, lustrous, smooth or spiny, mostly
brilliantly coloured. Inner lip flattened, with sharp or finely toothed margin ; outer

FIG. 856.

Lissochilus sigaretinus, Buv.
Coral-Rag; Hoheneggelsen,
Hannover.

Neritina G-rateloupana, Fer.
Miocene ; Haufelburg, near Giinz-
burg.

Fio. 859.

Pileolus plicatus, Sowb. Bathon-
in ; Langrune, Calvados. 3/j.

FIG. 857.

Velates Schmidelianus, Chem. Eocene (Lower
Meeressand) ; Cuise-la-Mothe.

lip sharp. Inhabits brickish or fresh water. Abundant in Tertiary and Recent. The
supposed Mesozoic forms belong principally to Nerita.

Pileolus, Sowb. (Fig. 859). Small, cup-shaped to depressed conical, ovoid or round.
Apex slightly curved backwards ; only the last whorl visible. Aperture semi-circular ;
inner lip broad, callous. Jura to Eocene.

ORDER ii CTENOBRANCHIATA— HETEROPODA— PLATYPODA 455

Order 2. CTBNOBRANCHIATA. Schweigg.

(Pectinibranchia, Cuvier ; Azygobranchia, Ihering ; Monotocardia, Bouvier.)

Eight cervical gill pectinate, very large, and usually transposed to the left side, owing
to torsion of the body ; the left gill atrophied. Heart with but one auricle. Radula
small, variously constructed, but usually armed with few teeth in a transverse series.
Shell coiled in a more or less elevated spiral, rarely cup- or cap-shaped.

The Gtenobranchiata constitute the largest group of the Streptoneura. They are
for the most part marine, but some are terrestrial, and some inhabit fresh water.
Beginning in the Silurian, they attain their maximum distribution in the Mesozoic,
Tertiary, and Recent periods. A division into two groups — Holostomata and Siphono-
stomata — according to the nature of the aperture, has been attempted ; but this is
unnatural, since it emphasises a shell character which is unaccompanied by any
anatomical differences. Classifications based upon the structure of the radula, such as
have been proposed by Troschel, and more recently by Bouvier, are valueless in
Palaeontology. Here it will be sufficient to recognise two sub-orders primarily :
Platypoda, in which the foot is normally developed ; and Heteropoda, in which it is
modified into a fin.

Sub-Order A. HETEROPODA. Lamarck.

(Nucleobranchiata, Blainville.)

To the Heteropoda belong naked or shell-covered, free -swimming and pelagic
marine Mollusks, with distinct head and highly developed sense organs. Heart, gills,
reproductive organs, and nervous system agree with the corresponding organs of the
Ctenobranchiates ; the radula resembles that of the Taenioglossa. They differ con-
siderably, however, from the Prosobranchiates, since the foot is modified into a sort of
vertical fin, and imparts to them a peculiar appearance. They rise usually toward
evening in great swarms to the surface of the ocean, where they
hover about with a very rapid motion, swimming in an inverted
position, with the dorsal side down, and the foot uppermost.
They are exceedingly delicate, often transparent organisms.
The body may be either entirely naked or provided with a
very thin, light shell.

Two recent genera have been found also in early Tertiary
deposits. Of these Carinaria, Lamarck, has a keeled, cap-
shaped, glassy shell ; while in Atlanta, Lesson (Fig. 860), the
delicate shell is coiled spirally in a single plane, and the

aperture is provided with a slit. Owing to the great similarity of Atlanta and
Oxygyrus to certain Palaeozoic Bellerophontidae, a relationship between the two has
been not unplausibly suggested. The latter forms are distinguished principally by
their heavier, thicker shells.

Sub-Order B. PLATYPODA.

Superfamily 1. GYMNOGLOSSA.

More or less completely parasitic forms, in which the radula is unarmed through
degeneration.

456

MOLLUSCS

SUB-KINGDOM VI

Family 1. Bulimidae. Fischer.

Small, polished, elongate-conic shells, with ovate apertures '; the axis often distorted ;
nucleus dextral. Trias to Recent.

Eulima, Risso (Fig. 861). Turreted, smooth, lustrous,
without umbilicus. Trias to Recent.

Niso, Risso (Fig. 862). Like the last, but with deep
umbilicus reaching to the apex. Trias to Recent.

Family 2. Pyramidellidae. Gray.

Shell turreted to elongate-oval. Aperture oval, an-
teriorly rounded, or with faint canal; outer lip sharp.
Operculum horny, spiral. Marine. Cambrian to Recent.

The nucleus consists of several whorls, and in
Palaeozoic and Mesozoic forms is coiled in the same
direction as the remainder of the shell. But in the

FIG. 861.

A, Eulima, sub-
ulata, Don. Plio-
cene ; Coroncina,
Tuscany. B, E.
polita, Linn.
Miocene; Nieder-
leis, Moravia.

FIG. 862.

Rome0'

Niso cburnea,
Risso. Plio-
cene ; Monte younger and more typical genera it is heterostrophic,

near distinctl7 separated from the rest of the shell, and often
stands at an angle with the adult spire. It is question-
able whether forms older than the Cenozoic can be retained in this family ; Fischer
places most of them in a new family, entitled Pseudomelaniidae.

Macrocheilus, Phil. (Macrochilina, Bayle ; Strobaeus, de Kon.), (Fig. 863). Elongate.-
oval, without umbilicus, smooth or with slightly curved growth-
lines. Spire acuminate, only moderately high ; last whorl
large. Aperture angular posteriorly, sometimes
with shallow anterior canal. Inner lip with
weak anterior folds. Silurian to Trias.

? Ptychostoma, Laube ; ? Undularia, Koken.
Trias.

Loxonema, Phil. Turreted, whorls arched,
with S- shaped growth -lines. Sutures deep;
aperture higher than wide, with shallow canal.
Silurian to Trias ; particularly
abundant in the Carboniferous.
Koken. Like

FIG. 864.

Zygopleura,
the last, but whorls with sharp,
slightly curved transverse ribs,
or transverse nodose keel. De-
vonian to Lower Cretaceous.

FIG. 863.

Pseudomelania
Heddingtonensis,
Sowb. sp. Ox-
fordian ; France.
Bands of original
coloration still
showing.

Macrocheilus arculntn^.
Schloth. sp. Middle De-
i • -TV i / r> -j.i 7 vonian ; Paffrath, near

Bourget^a, Desh. (Ptthodea, cologne.
de Kon.). Large, elongate-oval

to turreted, with large, inflated body whorl. Surface
marked with spiral striae or furrows. Carboniferous
and Upper Jura.

Pseudomelania, Pictet (Chemnitzia, p.p. d'Orb.),
(Bayania) ladea, (Fig. 864). Turreted, with numerous, almost flat

FIG. 865.
Psevdomelania

Lam.

caire

sp. Cal-
Grossier

whorls, and slightly impressed sutures. Surface
Grignon, near smooth, or marked by fine growth -lines ; aperture

rounded anteriorly, or with faint canal. Umbilicus
wanting ; rarely an umbilical fissure present. Very abundant in the Trias and Jura,
less so in Cretaceous and Eocene ; probably present also in the Carboniferous.

Coelost

Sub-genera : Oonia, Microschiza, Gemm. ; Hypsipleura, Anoptychia, Koken. Trias and Jura.
lostylina, Eustylus, Spirostylus, Kittl. Trias. Bayania, Munier-Chalm. Eocene. (Fig. 865.)

SUB-ORDER B

PLATYPODA

457

Pustularia, Koken. Turreted, with groove-like sutures. Whorls flat, with three
or more spiral rows of nodes. Trias.

Catosira, Koken. Whorls flat, with transverse ridges. Aperture canaliculate;
base with spiral grooves. Trias and Jura.

Diastoma, Desh. (Fig. 866). Like the last,
but aperture separated from the body whorl.
Whorls with transverse folds and spiral striae.
Cretaceous and Tertiary.

Mathilda, Semper (Promathilda, Andreae).
Turreted ; whorls transversely and spirally
striated or ribbed. Aperture with canal.
Nucleus heterostrophic. Jura to Recent.

Keilostoma, Desh. (Paryphostoma, Bayan),
(Fig. 867). Turreted, spirally striated. Outer
lip with externally thickened margin. Eocene.

Turbonilla, Risso (Chemnitzia, p.p. d'Orb.),
(Fig. 868). Small, turreted, with heterostrophic
nucleus. Whorls transversely ribbed or smooth.
Inner lip straight, or occasionally with folds.
Tertiary and Recent.

Odontostoma, Fleming (Fig. 869); Pyrami- n™^™?*™***
della, Lamarck (Fig. 870). Cretaceous to Recent.
Syrnola, Adams ; Eulimella, Fischer. Tertiary and Recent.
Trias and Jura.

The genera Subulites, Conrad (I Polyphemopsis, Portlock), from the Cambrian to
Carboniferous ; Fusispira, Hall, Ordovician ; and Soleniscus, Meek and Worthen, Car-

FIG. 867.

Fia. 800.

Lam. sp.

eostellata,
Calcaire

turri-
culu, IJruj:. sj>.
(Mi l>i a ;« iiiiiriiiii'it''.
Lam.) ; Calcaire
Grossier ; Grignon,
near Paris.

Palaeoniso, Gemm.

FIG. 808.

Turbonilla rufa,
Phil. Crag; Sntton,
England.

FIG. 869.
Odontostoma pli-
cata, Montf. sp.
Upper Oligocene ;
Nieder-Kaufnngen,
near Cassel.

Pyramidella pli-
cosa, Bronn. Mio-
cene ; Niederleis,
Moravia.

Euchrysaiis fusi-
formis, Mvinst.
sp. Trias ; St.
Cassian. Tyrol.

boniferous, are characterised by narrow, anteriorly elongated and canaliculate aper-
tures. They probably form a separate family, in which also should be placed the
Triassic Euclirysalis, Laube (Fig. 871).

Superfamily 2. PTENOGLOSSA. Gray.

Teeth of the radula subulate, numerous, and similar in each transverse row.

Family 1. Scalariidae. Broderip.

Shell turreted, usually narrowly umbilicate. WTiorls convex, transversely ribbed or
striated. Aperture round, with entire peristome. Operculum horny, paucispiral.
Marine. Silurian to Recent.

Holopella, M'Coy (Aclisina, de Kon.). Slender, turreted ; whorls with fine trans-
verse striae, sometimes cancellated. Silurian to Carboniferous.

458

MOLLUSGA

SUB-KINGDOM VI

Callonema, Hall (Isonema, Meek and Worth). Turreted, oval to globose ; whorls
covered with lamellate transverse ribs ; aperture circular. Silurian and Devonian.

Scoliostoma, Braun. Devonian. Chilocyclus, Bronn (Cochlearia,
Braun). Trias.

Scalaria, Lam. (Scala, Klein ; Cirsotrema, Morch.), (Fig. 872).
Turreted; whorls strongly arched, with transverse ribs, and often
also spirally striated. Aperture round, outer lip sometimes thickened.
Trias to Recent.

Family 2. Solariidae. Chenu.

Shell depressed conical, deeply and broadly umbilicate, without
nacreous layer. Whorls angular; operculum horny or calcareous,
spiral. Embryonal spire
heterostrophic. Marine.
FIG 872 Cretaceous to Recent.

Scalaria lamellosa, mi ^nTnrt'irlnf PY

Brocchi. Miocene;
Baden, near Vienna, hibit some resemblance to

the Euomphalidae, from
which they are distinguished principally
by the heterostrophic nucleus.

Solarium, Lam. (Figs. 873, 874).
Aperture quadrilateral ; operculum horny ;
umbilical angle notched or sharp. Jura
to Recent. A number of Mesozoic forms confused with this genus probably belong to
Euomphalus.

Torinia, Gray. Tertiary and Recent. Bifrontia, Desh. (Omalaxis, Desh.). Eocene.

FIG. 873.
Solarium simplex,

Miocene ;
Niederleis, Moravia.

FIG. 874.

Solarium Leymeriei, Ryckholt.

(Uppe
Tournay, Belgi

Superfamily 3. TAENIOGLOSSA. Bouvier.

Teeth of the radula seven in each transverse row. Mainly holostomate forms, but
some genera have deeply notched apertures, as in the higher divisions.

Family 1. Purpurinidae. Zittel.

Thick-shelled, oval, with platform-like spire, and without
<iyer. Whorls flattened beneath the suture and
angular, the angles often beset with nodes. Body whorl
large ; aperture oval, with anterior emargination, and
discontinuous peristome. Operculum unknown. Ordo-
vician to Cretaceous.

Scalites, Conrad. Spire short and acuminate ; whorls
flattened superiorly and bounded by a sharp angle at the
suture. Body whorl very large, smooth ; aperture faintly
notched. Ordovician (Chazy) ; according to Laube, also
Triassic.

FlG 875. Trachydomia, Meek and Worth (Trachynerita, Kittl) ;

Purpuroideanoduiata, Young and Pseudoscalites, Kittl ; Tretospira, Koken. Trias. Brach-
Bird sp. Great Oolite ; Minchin- trema, Morris and Lvc. ; Tomocheilus, Gemm. Jura.

hampton, England. ' . -,,,^11 , „-,-, , i

Purpunna, d Om. Elongate-oval. Whorls angular

superiorly, spirally ribbed, with transverse folds or costae, highly ornamented, often
with umbilical fissure. Aperture oval, anteriorly notched. Rhaetic and Jura.

Purpuroidea, Lycett (Fig. 875). Spire with successive steps or platforms, the

SUB-ORDKK I!

PLATYPODA

459

surface beneath tin* suture bounded by a row of nodes. Last whorl inflated,
smooth. Aperture anteriorly with canal -like notch; outer lip thin. .Jura and
( 'rrtaivnus.

Brachytrema, Morris and Lycett ; Tomocheilus, Gemni. Jura.

FIG. 876.
Turbonitella subcostata,

Family ± Littorinidae. (iray.

Shell turbinate, usually smooth or spirally ornamented, without nacreous layer.
Aperture rounded ; outer lip sharp. Operculum horny, paucispiral. Marine. Ordo-
vician to Recent.

Fossil shells of this family are distinguished solely from those of tin- 7W/,/',i/V/"r

and Trochidae by the absence of a pearly layer. The animal,

however, differs radically. The heart has but one auricle in

the Littorinidae, two in the Turbinidae and Trochidae. The

radula in the last -named groups is rhipidoglossate ; in the

present family it is taenioglossate. The differences in essential

structure are thus seen to be considerable ; yet the shells when

fossilised are so similar, it can scarcely be doubted that the

so-called Palaeozoic Littorinidae are in many cases very closely

related to genera referred to the Turbinidae and Trochidae.

The limits of these families are therefore very uncertain, so

far as Palaeozoic forms are concerned. Among the extinct

genera which exhibit great similarity to Littorina, but are

often assigned to the above-named families, may be mentioned

the following : — Holopea, Hall ; Ordovician to Devonian.

Turbonitella, de Koninck (Fig. 876) ; Devonian and Carboniferous. Portlockia,

Turbinilopsis, and Rhab-
dopleura, de Koninck ;
from the Carboniferous.
Lacunina, Kittl ; Trias.
Littorina, Fer. (Fig.
877). Thick -shelled,
turbiuate to globose,
smooth or spirally
striated, without um-
bilicus. Aperture oval.
Jura to Recent.

Lacuna, Turton

(Fig. 878). Like the last, but with a narrow umbilical fissure. Tertiary and Recent.
Lacunella, Desh. ; Eocene. Litiopa, Rang ; Planaxis, Lam. ; Quoyia, Desh. ;

Tertiary and Recent. The families Litopidae and Planaxidae are usually recognised.
The genus Fossarus, Phil. (Fig. 879), forms, according to Fischer, a separate family,

Fossaridae. It occurs in the late Tertiary and Recent.

FIG. 877.

Littorina littorea,
Linn. sp. Post-
Pleistocene ; Isle
of Skapto.

FIG. 878.

Lacuna Bastero-
tina, Bronn.
Miocene ; Steina-
brunn, near
Vienna.

Fossarus costatus, Brocchi.
cene ; Liinite, Tuscany.

Plio-

Family 3. Cyclostomidae. Menke.

Shell extremely variable in form, turbinate to discoidal, sometimes turreted, covered
with epidermis. Aperture circular, with usually entire peristome. Operculum horny or
calcareous, spiral. Terrestrial. Cretaceous to Recent.

Like the pulmonate snails, tl^fciimal possesses a respiratory cavity. But in
other respects they approach the L^^nnidae very closely, which latter forms also
have the gill much reduced. The shell Habit is excessively variable. There are more
than 600 recent species distributed throughout all parts of the globe, but the majority

460

MOLLUSGA

SUB-KINGDOM VI

of these are tropical. Fossil forms are found in fresh -water deposits as old as the
Middle Cretaceous.

Cyclostoma, Lam. (Fig. 880). Turbinate, with calcareous spiral operculum.
Tertiary and Recent.

Otopoma, Tudora, Gray. Tertiary and Recent.

Megalomostoma, Guild. Turbinate to chrysalis-shaped, usually smooth. Peri-

Fio. 880.
Cyclostoma bi-
sulcatum, Zieten.
Miocene ; Ermin-
gen, near Ulm,
Wurtemberg.

FIG. SSI.

Pomatias labellum,
Thomas sp. Helix
Beds (Upper Oligo-
cene) ; Hochheim,
near Wiesbaden.

FIG. 882.

Cydotus exaratus, Sandb.
Upper Eocene ; Pugnello,
'Italy. Shell and operculum
(after Sandberger).

Strophostoma anom-
phala, Capellini. Oli-
gocene ; Arnegg, near
Ulm, Wurtemberg.

Operculum horny. Cretaceous to

stome with thick margins ; outer lip reflected.
Recent. M. mumia, Lam. sp.

Pomatias, Studer (Fig. 881). Turreted, transversely striated, with reflected
margins and calcareous operculum. Tertiary to Recent ; palaearctic.

Leptopoma, Pfeiff. ; Cyclophorus, Montf. ; Craspedopoma,
Pfeiff. ; Cydotus, Guilding (Fig. 882), etc. Upper Cretaceous.
These genera are considered to form a distinct family, Cyclo-
phoridae. Strophostoma, Desh. (Fig. 883) ; Upper Cretaceous
to Miocene.

Family 4. Capulidae. Cuvier.

Shell cup-, cap -shaped, or oval,
irregular, with spirally twisted apex;
in some cases the shell is composed of
several depressed whorls. Body whorl
very large ; aperture wide ; operculum
absent. Marine. Cambrian to Recent.

Various genera belonging here
are stationary, remaining throughout
nearly the whole of their existence
attached to some foreign body, to
which they gradually become accom-
modated in form.

Stenotheca, Salter. Shell small,
cap-shaped, concentrically striated or
FIG. 886. furrowed, with slightly incurved

elegans, Barr. apex, which latter is distantly situated

Capulus hitngaricus, Linn,
sp. Pliocene ; Tuscany.

. , .

BoheS eE);LOChk°W' posteriorly. Lower Cambrian.

FIG.

Capulus rugosus, Sowb. sp.
Great Oolite ; Langrune,
Calvados. 1/1- ^^1..^..

Capulus, Moritf. (Pileopsis, Lam. ;

Brocchia, Bronn), (Figs. 884, 885). Irregularly conical or cap-shaped ; apex greatly dis-
placed backward, more or less spirally inrolled. Aperture wide, rounded or irregular -r
internally with a horseshoe-shaped muscular itttjHfession. Exceedingly abundant from
the Cambrian to Carboniferous, but rather sparse from the Trias onward.

Orthonychia, Hall (Igoceras, Hall), (Fig. 886). Shell conical, straight, or slightly
curved, often plicated. Apex but faintly spiral. Silurian to Carboniferous.

SUB-ORDER B

PLATYPODA

461

Platyceras, Conrad (Acroculia, Phil.), (Fig. 887). Apex bent and spirally inrolled.
Surface smooth, striated, plicated, or covered with small spines. Cambrian to Trias.
The fusion of this genus with Capulus, as proposed by some authors, is hardly
justifiable.

Platyostoma, Conrad (Strophostylus, Hall), (Fig. 888). Shell composed of numerous
rapidly widening whorls. Spire low, body whorl very large. Inner lip reflected and
somewhat thickened. Aperture round, of large size. Silurian to Carboniferous.

FIG. 887.

I'l, it !icc rat, nr.ritoidus, Phil. Car-
boniferous ; Vise, Belgium.

I'fut i/ostoma, niaqarensis,
Hall. Devonian ; Waldron,
Indiana.

Horiostoma Jiarrandei, Mun.-Chalm.
Lower Devonian ; Gahard, Ille-et-
Vilaine (after Munier-Chalmas).

Horiostoma, Mimier-Chalm. (Fig. 889). Shell thick, spirally ribbed, with short
lateral spire, and wide umbilicus. Devonian.

Tubina, Barr. Silurian. Rothpletzia, Simonelli. Tertiary.

Hipponyx, Defr. (Cochlolepas, Klein), (Fig. 890). Shell thick, obliquely conical to
cup-shaped. Beak straight, rarely spiral, greatly removed posteriorly. Aperture oval or
A rounded, internally with a horseshoe-shaped muscular impression. The foot

often secretes a thick, operculiform calcareous disc. Cretaceous to Recent.

Galerus, Gray (Calyptraea, p.p. Lam.).
Shell thin, conical, with central spiral

FIG. 890.

Hipponyx cornucopiae, Lain. Cal-
caire Grassier ; Liancourt, near
Paris. A, Shell. B, Foot-plate.

FIG. 891.

Creptdvla trnmti-

formis, Lain. Plio-
cene ; Tuscany.

FIG. 892.

Cnlyptraea trnchiformis, Lam.
DamiM-y, near Epernay.

Calcaire Grossier ;

apex. Whorls flattened, often spinose. Base horizontal; aperture wide, depn •.->.•<!.
Cretaceous to Recent.

Crepidula, Lam. (Fig. 891). Slipper-shaped, elongate-oval, flat or arched. Beak
at the posterior end, almost marginal, somewhat curved. Aperture greatly elongated,
wide ; inner lip formed by a thin horizontal lamella. Cretaceous to Recent.

Grucibulum, Schum. ; Calyptraea, Lam. (Fig. 892). Tertiary and Recent.

Family 5. Naticidae. Forbes.

Shell with short spire and large body whorl. Aperture semi-circular to oval, angular
posteriorly, broadly rounded anteriorly. Operculum calcareous or horny, paucispiral.
Marine. Trias to Recent.

The distinction of fossil Naticidae from Naticopsis, Nerita, and Ampullaria is

462

MOLLUSCA

SUB-KINGDOM VI

attended with great difficulty, since they frequently possess nearly identical- characters
in common, differing mainly in the operculum, which is not preserved fossil.

FIG. 893.

Sigaretus haliotoideus,
Linn. sp. Miocene;
Grund, Hungary.

A , Natica millepunctata , Lain. Plio-
cene ; Monte Mario, near Rome. B,
Operculum of N. multipunctata, S.
Woodw. Crag; Sutton.

FIG. 895.

Natica (Ampullina) patula,
Lam. Calcaire Grossier ;
Damery, near Bpernay.

Sigaretus, Lain. (Fig. 893).
Spire very low, with
distended ; operculum

Natica, Lam. (Figs.
pyramidal, smooth and

FIG. 896.

Natica (Amaur-
opsis) Willemeti,
Lam. Calcaire
Grossier ; Damery,
near Epernay.

FIG. 897.

Natica (Amauropsis) bul-
biformis, Sowb. Upper
Cretaceous ; St. Gilgen
on Wolfgangsee, Austria.

Shell depressed, auriform, spirally striated or furrowed,
rapidly widening whorls. Aperture greatly
horny. Tertiary and Recent.
894-897). Globose, semi-globose, ovate or
lustrous, rarely spirally striated, umbilicate
or not. The umbilicus, when present, often
partially or entirely filled with callus.
Aperture semi - circular or oval. Outer lip
sharp; inner lip
thickened by a callus.
Excessively abundant
from the Trias onward.

Sub -genera : Ampul-
lina, Lam. (Fig. 895) ;
Amauropsis, Morch (Figs.
FlG gyy 896, 897) ; Amaura, Moll.;

Deshayesla c'ochlearia, %™*™> Cernma Gray ;
Brongt, sp. Oligocene ; Neventa, Risso ; Maimlla,
Monte Grumi, near Schum., etc.

Vicenza.

Raul.

Miocene

(Fig. 898). Like Natica, but inner lip with thick callus and denticulated,
and Pliocene.

Family 6. Xenophoridae. Deshayes.

Shell turbinate, without nacreous layer ; whorls flat, often covered with agglutinated
foreign bodies. Base conical or fiat, with a sharp peripheral keel.
Aperture obliquely quadrilateral. Operculum horny. Silurian
to Recent.

The Xenophoridae are an ancient family, the modern re-
presentatives of which have acquired a high differentiation.
The radula is like that of the Gapulidae, Littorinidae, and
Strombidae, not like that of the Trochidae. The earlier forms,
encountered in the Silurian, present a great superficial re-
semblance to the Palaeozoic Trochus species.

Eotrochus, Whitf. (Fig. 899). Thin-shelled, turbinate, widely \
umbilicate. Whorls flat, rarely with agglutinated foreign particles.
Base concave, its periphery formed by a compressed lamellar belt.

Xenophora heiiacua, d'Orb.
1*

Silurian to Recent.

SUB-ORDER B

PLATYPODA

AC,:}

The \vi<l«-

i>mj>halopterus, Roem. Depressed turbinate, widely umbilicatt
pheral margin at the base composed of two lamellae,
separated by a slit. Silurian.

Clisospira, Billings ; Autodetus, Lindstroiu. Silurian.

Xenophora, Fischer (Phorus, Monti.), (Fig. 900). Low
trochiform, narrowly uinbilicate. Whorls usually covered
above with agglutinated extraneous objects. Cn-tan-mi.- t<>
Recent.

Family 7. Ampullariidae. (!ra\.

This family inhabits fivsh or brackish \\aln-. ;m>l ifl
found in Africa, Asia, and tropical America. Some of
their shells are hardly to be distinguished from Natica.
The animal possesses a lung cavity above the right gill.
Fossil forms occur in freshwater deposits of Cretaceous age at Rognac, near Marseilles,
and also in the early Tertiary.

,.•„, ,MHI

xenophora aggiutinans, Lam.
Growler; Dwwry, new

Fia. 901.

Valvata piscinalis, Mull.
Upper Miocene ; Vargas,
Transylvania.

Family 8. Valvatidae. Gray.

Shell composed of few whorls, conical or discoidal, umbilicate. Aperture round, with
continuous peristome. Operculum horny, circular, multispiral.
Upper Jura to Recent.

The genus Valvata, Hull. (Fig. 901), is small, and varies
from turbinate to discoidal. It comprises about twenty-five
recent species, inhabiting the fresh waters of Europe and North
America. It is initiated in the Purbeck, but does not become
at all abundant until the Tertiary.

Family 9. Viviparidae. Gill.

Shell conical or turbinate, with thick epidermis; imperforate or with narrow
umbilicus. Whorls smooth, tubular or angular. Aperture rounded, oval, sub-angular
posteriorly, with continuous peristome. Operculum horny, concentrically striated, with
eccentric nucleus. Jura to Recent.

Viviparus, Montf. (Paludina, Lam.), (Fig. 902). This, the principal genur-, i>
abundant in fresh water of all parts of the globe, with the exception of tropical and
South America. Several A B c Jf

other genera and sub-
genera are recognised,
such as Campeloma, Raf.
(Melantho, auct.), of
North America, compris-
ing mostly smooth, thick -
shelled species, with
thickened inner lip;
Tulotoma, Haldem., in-
cluding forms with an-
gular whorls, North
America; Margarya,
Nev., China ; Lioplax,
Brusina, etc.

Typical species of this genus are found in the Wealden clays. Vast numbers of
Viviparus occur in the Pliocene of Southern Hungary, Croatia, Slavonia, Roumania,

FIG. 90-2.

A, B, Viviparus Brusinae, Neumayr. C, V. (Tulotoma) Forbesi, Neumayr.
Pliocene ; Isle of Cos. D, V. (Tulotoma) Hocnuri, Neumayr. Pliocene •,
Novska, Slavonia.

Troschel ; Laguncula, Benson ; Tylopoma, Boskoviciar

464

MOLLUSCA

SUB-KINGDOM VI

and the Island of Cos, where they are remarkable for their extreme variability.
Neumayr has described a number of mutation series from this horizon, which begin
with smooth Viviparus species, and terminate with angular Tulotoma-like forms.

Family 10. Amnicolidae. Try on.

Shell turbinate to turreted, small, usually thin, and either smooth, longitudinally
ribbed, or spirally keeled. Aperture ovate; operculum horny or calcareous, spiral or
concentric. Cretaceous to Recent.

These are fresh or brackish water inhabitants, some of which, however, are able to
survive for a considerable period on lajid. It is difficult to distinguish the different
genera belonging to this family by means of shell characters alone.
All the forms are diminutive.

Bythinia, Leach (Fig. 903). Thin -shelled, turbinate, with
umbilical fissure. Peristome continuous, outer lip sharp. Oper-
culum calcareous, concentric. Wealden to Recent.

FIG. 903.

A, Bythinia tentaculata,
Linn. sp. Upper Mio-
cene ; Miocic, Dalmatia.
B, Operculum of same.
C, B. gracilis, Sandb.
Fresh -water Molasse ;
Oberkirchberg, near Ulin.

•^ys/
\

FIG. 904.

Nematura pupa, Nyst.
sp. Oligocene ; Hacken-
heim, near Alzey.

«/ w

FIG. 905.

Nystia Chastelii,
Nyst. sp. Middle
Oligocene; Klein-
Spouwen, Belgium.

W

P'iG. 906.
Hydrobia (Litori-
nella) acuta, A.
Braun. Miocene ;
Weissenau, near
Mayence.

Staliola, Brusina. Outer lip thickened ; operculum calcareous. Cretaceous to
Miocene.

Fossarulus, Neumayr. Like the last, but with spiral ribs. Upper Miocene.

Nematura, Benson (Stenothyra, Benson), (Fig. 904). Like Bythinia, but aperture
contracted. Operculum calcareous, spiral. Tertiary and Recent.

Nystia, Tourn. (Forbesia, Nyst.), (Fig. 905). Outer lip reflected ; operculum
calcareous, spiral. Tertiary and Recent.

Assiminea, Leach. Tertiary and Recent.

Hydrobia, Hartm. (Littorinella, Braun ; Tournoueria, Brusina), (Fig. 906). Conical
to turreted, acuminate, smooth. Aperture oval ; operculum horny, paucispiral.
Cretaceous to Recent. The Indusia Limestone (Lower
Miocene) of Auvergne is almost exclusively composed
of the shells of H. Dubuissoni, Bouill. Similarly, the
Littorinella Limestone of the Main Basin which is of
equivalent age, is made up of the shells of H. acuta,
Braun. Strata in the fresh-water limestone of Nord-
lingen are charged with H. trochulus, Sandb. ; and
the Upper Eocene marl of St. Ouen is filled with
the remains of H. pusilla, Prev. sp.

A,Pyrqula Eugeniae, Neumayr. Upper

Other genera and sub -genera closely related to Miocene; Arpatak, Transylvania. B,

Onnlr] • Micromelania(Diana) Haueri, Neumayr.
^ 1Q , gp upper Miocene; Miocic, Dalmatia.

Lapparentia, C, Mohrenstemia inflata, Andrzewsky.
Congerien Stage (Miocene) ; Inzersdorf,
near Vienna.

FIG. 907.

thp fnrprrrvmo- arp Riit'h'itiplln Mnn •
Ua, MOq. ,

Belgrandia, Lartetia, Bourguignat ;
T, .-, •, •

lin-

Pyrgula, Christofori and Jan. (Fig. 907, A}.

Turreted, whorls spirally keeled or ribbed. Peristome continuous. Tertiary and
Recent.

Genera allied to the last are Micromelania, Brus. (Fig. 907, B) ; Mohrenstemia,
Stol. (Fig. 907, C) ; Pyrgidium, Tournouer ; Prososthenia, Neumayr. Tertiary.

SUB-ORDER B

PLATYPODA

465

Lithoylyphus, Ziegl. (Fig. 908). Globose or ovate, with short spire; ratln-r thi'-k
and solid. Aperture large, obliquely oval ; inner lip thickened.
Tertiary and Recent; Europe. Similar forms, Somatoyyrus, (lill,
and Flumincola, Stimpson, occur in North America. There a»e
other related genera in South-Eastern Asia and South America.

Pro. i»08.

Ufhoglypkus fu&cus,
Xic-l.-r. Upper Mio-
cene ; Mali no, West
Slavonia.

Family 11. Rissoidae. Troschel.

Shell small, thick, turbinate to turreted, usually ribbed or spirally
striated, rarely smooth. Aperture oval, angular posteriorly, often with
anterior canal. Operculum

horny, pa ucispiral. Jura to ' B A

Recent.

Rissoina, d'Orb. (Fig.
909). Turreted, transversely
ribbed, rarely smooth ; outer
lip arcuate, generally
thickened ; aperture some-

FIG. 910.

FiG. 909.

.!, Rimotaa amoeno, Zitt Tithon-
what notched or effuse at ^L^JiS' SS^sSuf:

the base. Dogger to Recent ; brunn, near Vienna,
mainly Tertiary.

Rissoa, Frem. (Fig. 910). Turreted, transversely ribbed or cancellated, aperture
entire below. Jura to Recent.

A, Rissoa turbinnl". Lain. sp.
Oligocene ; Wcinlit-im, near
Alzey. If, /.'. (Aim it!") M<,,>-
tugui, Payr. Miocene ; Steina-
brunn, near Vienna.

Family 12. Turritellidae. Gray.

Shell turreted, with high acuminate spire. IVlwrls numerous, usually spirally ribbed
or striated. Aperture oval, round or quadrangular, sometimes with faint anterior canal.
Outer Up thin, peristome discontinuous. Operculum horny,
multispiral. Marine. Trias to Recent.

Turritella, Lam. (Figs. 911, 912). Spire very high;
aperture oval or rounded quadrilateral ; outer lip thin,
excavated behind, and slightly produced in front. Trias
to Recent ; maximum in Tertiary. The older Mesozoic

species are usually
small.

Sub-genera : Me-
so/to, Gray (Fig. 912).

Like the last, but
aperture with shallow
canal, and twisted
inner lip. Tertiary
to Recent.

Protoma, Baird
(Proto, p.p. Defr.).
Aperture oval, an-
teriorly with canal-
like contraction,
which is surrounded
externally by a thick
swelling. Tertiary
and Recent. P.
cathedralis, Brgt.

Glauconia, Giebel (Omphalia, Zekeli ; Cassiope, Coq.), (Fig. 913). Thick-shelled,
conical to turreted, narrowly umbilicate. Whorls spirally ribbed, rarely smooth.
VOL. I 2 H

FIG. 911.

A, Turritella turris, Bast. (T.
terebra, Ziet. non Linn.)- Mio-
cene Molasse ; Ermingen, near
Ulin. li, T. imbricataria, Lain.
Calcaire Drossier ; Grignon, near
Paris.

FIG. 912.

TwrriteOa (Mesalia)
multisulcuia, Lain.
Eocene; Calcaire
Grossier ; Grignon,
near Paris.

FIG. 913.

(rlauconia Kefersteini,
Goldf. Middle Cre-
taceous ; Dreistatten,
near Wiener-Neust.

466

MOLLUSQA

SUB-KINGDOM VI

Aperture oval, with faint canal ; outer lip with anterior and median emargination.
Abundant in the Cretaceous.

Family 13. Vermetidae. Adams.

Shell tubular, the earlier whorls spiral, the later ones irregularly twisted, free or
attached. Aperture round ; operculum horny, sometimes wanting. Carboniferous to
Eecent.

Some fossil Vermetidae are liable to be mistaken for Serpulidae, but differ from
them nevertheless in the structure of
the shell and spiral nucleus. The
determination of the few Palaeozoic
and Mesozoic forms is uncertain.

Vermetus, Adans. (Figs. 914, 915).
Shell usually attached, irregularly
tubular, internally vitreous, and often
with septa. Carboniferous (?) to Recent.
Abundant in the Tertiary.

FIG. 914.

Vermetus (Thylacodes) arenarius, Linn.
Miocene ; Grund, near Vienna. 1/2-

FIG. 015.

Petaloconchus intortus, Lain
Pliocene ; Montespertoli, near
Florence. Some of the tubes are
fractured, and show the internal
lamellae.

FIG. 910.

Siliquaria, striata
Desh. Calcaire Grossier;
Chaussy, near Paris.

Sub-genera : Thylacodes, Guettard (Fig. 914) ; Petaloconchus, Lea (Fig. 915).
Recent.

Tertiary and

Siliquaria, Brug. (Fig. 916). Shell free, coiled in a loose spiral. Aperture lateral,
and with a slit which continues as a fine cleft or row of pores throughout the entire
length of the shell. Cretaceous to Recent.

Family 14. Caecidae. Adams.

Shell small, discoidal in early stages, later becoming tubular. TJie decollated nucleus
replaced by a septum. Operculum round, horny. Tertiary and Recent.

Caecum, Flem. About one hundred Recent and twenty Tertiary species are known.

Family 15. Melaniidae. (Lamarck) Gray.

Shell turreted to oval, with thick, dark-coloured epidermis. Apex usually truncated
and corroded. Aperture oval, sometimes canaliculate. Operculum horny, spiral. Jura
to Recent.

SUB-ORDER 1?

PLATYPODA

467

Living species inhabit fresh, or more rarely brackish, waters of Southern Eui"|..
and the warmer zones of Africa, Asia, and America.

Melania, Lam. (Fig. 917). Shell smooth or spirally striated, or
with transverse ribs or nodes. Aperture oval, anteriorly rounded.
Upper Jura to Recent.

Stomatopsis, Stache. Whorls platform-like, with strong trans-
verse ribs ; aperture rounded, with entire, thickened, and reflected
margins. Lowermost Eocene (Cosina Beds) ; Istria and Dalmatia.

Pyrgulifera, Meek (Hautkenia, Munier - Chalm.), (Fig. 9 1 8).
Shell thick, elongate - oval, with platform - like, transversely
ribbed, and spirally striated whorls. Aperture oval, sometimes
with very faint canal. Upper Cretaceous of Europe and North
America.

Paramelania, Smith. Eesembles the preceding. Living in
Lake Tanganyika.

Fascinella, Stache ; Coptostylus, Sandb. ; Faunus, Montf. ; Herni-
X//M/X, Swainson. Upper Cretaceous, Eocene, and Recent.

Melanopsis, Fer. (Figs. 919-921). Shell oval to turreted, smooth
or ornamented. Base of columella truncated ; aperture with short
canal ; inner lip callous. Upper Cretaceous to Recent. Remarkably
abundant in Miocene and Pliocene.

Pleurocera, Raf. (Fig. 922). Like Melania, but aperture with faint canal, and
outer lip sinuous. Cretaceous to Recent ; occurs only in North America.

Ki<;. '.'17.

Mi-luniii /•.'.-•«•/« ,-.".
nongt. .V

Pyrgulifera Pich-
hri, Hoernes sp.
Upper Creta-
ceous ; Ajka,
Hungary.

Mrlnnnpsis gallo-pro-
vincialis, Math. Upper-
most Cretaceous ; Mar-

t i.nues, near Marseilles.

FIG. 920.
Melanopsis M<ir-
tiniana, Fer. Mio-
cene ; Nussdorf,
near Vienna.

Melanopsis (Can-
thidomus) acciith /<•»,
Neumayr. Upper
Miocene ; Miocic,
Dalmatia.

FID. •••_••_•.

Pte*roamttnmbi-

formis, Schloth. sp.
Wealden ; Ostei-
wald, Hannover.

Goniobasis, Lea ; Anculosa, Say (Leptoxis, Raf.) ; Ptychostylus, Sandb.
The first two occur Tertiary arid Recent in North America only.

Wealden.

Family 16. Nerineidae. Zittel.

Shell turreted, pyramidal, or ovate, perforate or imperforate. Aperture anteriorly
with short canal or shallow notch. Columella and lips with strong folds, continuous
throughout the entire length of the spire. Outer lip thin, posteriorly with fissure-like
incision, which leaves a small slit-band immediately beneath the suture on all the whorls.
Marine. Trias to Cretaceous.

Aptyxiella, Fisch. (Aptyxis, Zittel non Troschel). Turreted, very slender, im-
perforate. Aperture quadrangular; inner and outer lips without folds; cohuuella
somewhat thickened. Trias to Upper Jura.

468 MOLLUSCA SUB-KINGDOM vi

Trochalia, Sharpe (Cryptoplocus, Pict. and Camp.), (Fig. 923). Turreted to

FIG. 9-23.

FIG. 024.

Trochalia consobrina, Zitt. A, Nerinea Defrancei, d'Orb. Coral-Rag; Coulanges 8ur Yonne. J>, N.

Tithonian; Stramberg, dilatata, d'Orb. Coral-Rag; Oyonnax, Ain. C-E, N. Hoheneggeri, Peters.
Moravia. Longitudinal section. Tithonian ; Stramberg, Moravia. C, 2/3. D, i/la E, Longitudinal section.

pyramidal, usually smooth and imperforate. The inner lip only has a strong, simple
fold. Jura and Cretaceous.

Nerinella, Sharpe (Pseudonerinea, Loriol). Turreted, imperforate. Outer lip and
sometimes also the columella with a simple fold. Jura.

Nerinea, Defr. (Fig. 924). Turreted or pyramidal, usually
imperforate. Columella invariably, and inner and outer lips
generally, with simple folds. Jura and Cretaceous ; maximum in
the Coral Rag (Upper Jura).

Ptygmatis, Sharpe (Fig. 925). Like the last, except that the
folds on both lips and the columella are
complicated by secondary constrictions and
branchings. Jura and Cretaceous.

Itieria, Math. (Fig. 926). Elongate-oval,
usually umbilicate. Spire short, sometimes
insunken. Body whorl very large, more or
less enveloping the preceding. Columella
and both lips with folds. Jura and Cre-
taceous.

FIG. 925.

Ptygmatis pscudo-
bruntmtana, Gem-
mellaro. Tithonian;
Imvald, Carpathia.
Vertical section.

FIG. 926.

Itieria Staszycii, Zeuschner.
Tithonian; Inwald and
Stramberg.

Oerithiidae. Menke.

Family 17.

Shell turreted ; aperture elongated, oval,
or quadrilateral, anteriorly with short canal
Outer lip often thickened and reflected, or thin and sharp. Columella sometimes with one
or two folds. Operculum horny, spiral. Marine and brackish water. Trias to Recent.

More than 1000 living, and about 500 fossil species are known, the latter being
most numerous in the Eocene. The earliest forms are usually of small size, and have
a nearly entire peristome.

SUB-ORDER B

I'LATVI'ODA

ha MT.

CerithliH'llii unit'ito,
Goldf. Torulosus

FN.. 928.

Morris ami I.\ <•.
Cn-at oulit- : Miii-
fhinhainptoii.

land.

Cerithinella, Oemin. (Fig. 927). Shell turreted, slender. \Vln.i]- nuiiit-roii.-, Hat.
ornamented with spiral ribs or rows of small node<.
Aperture quadrilateral, with very faint canal. Jura.
Cryptaulax, Tate (Pseudocerithiurn, ( 'n.-.-iiiaiin .
Small, turreted. Whorls with spiral ribs or rows
of nodes and transverse folds. These last usually
run continuously in a somewhat oblique direction
from one whorl to the next. Aperture oval or
quadrila.teral,'with scarcely percep-
tible canal. Trias and Jura.

Ceritella, Morris and Lye. (Fig.
1)28) ; Trias and Jura, Fibula,

Piette (Fig. 929) ; Trias to Cretaceous. Pseudalaria, Huddli-M. :

Ditretus, Piette ; Jura.

Exelissa, Piette (Fig. 930). A'. • ry
small, turreted ; whorls with strong,
continuous transverse ribs and spiral
striae. Aperture contracted,
rounded, without canal, sometim.-.-
slightly separated off, and with
continuous peristome. Abundant

Fm. 931. in t]ie Jura-

Bittium plicatum Bittium, Leach (Fig. 931). Tur-

Brug. Oligocene; -, . , .,

Ormoy, near Etampes, reted, with granulated spiral ribs, and

France- numerous trans verse costae. Aperture

with short, straight canal ; outer lip sharp. Jura to Recent. Abundant in the Tertiary.
Triforis, Deshayes ; Cerithiopsis, Forbes. Tertiary and Recent.

Eustoma, Piette. Aperture with long canal, which is often
closed, however, by margins of the inner and outer lip. Inner lip

callous and strongly
dilated; outer lip ex-
panded. Jura.

Fio. 929.

Fibula undulosa,
Piette. Bathon-
ian ; Eparcy,
Aisne.

FK;. 930.

Exelissa strangu-
lata, d'Arch. sp.
Bathonian ;
Eparcy, Aisne.

FIG. 932.

Cerithium sermtum,
Brug. CalcaireGrossier;
Dainery, near Epernay.

FIG.

Cerithium, (Vertagus)
7ii«{u?n, Lani. Eocene;
Chaumont, near I'aris.

Fio. 934.

Potamides (Tympana-
torn «*•) margaritaceum,
Brocchi. Oligocene;
Hackenheim, near Alzey.

Fio. 935.
Potamides (I.i'
pli'iiri'tmnoiiJes, Desh.
Middle Meert'ssand ;
Mortefontaine, Seine-
et-Oise.

Cerithium, Brug. (Figs. 932, 933). Turreted, imperforate, without epidermis.
Aperture oblong, ovate, with backwardly curved canal ; outer lip often somewhat re-
flected. Columella concave, frequently with one or two folds. Certain Tertiary species
attain a length of half a meter (C. giganteum). Jura to Recent ; maximum in Eocene.
Sub-genera : Vicarya, d'Arch. ; Vertagiis, Klein (Fig. 933) ; Bellardia, Mayer, etc.

Potamides, Brongt. (Figs. 934, 935). Turreted, with epidermis ; aperture with

470

MOLLUSGA

SUB-KINGDOM VI

emargination or faint canal. Inhabits only brackish water or estuaries. Cretaceous
to Recent.

Sub-genera : Tympanotomus, Adams (Fig. 934) ; Pyrazus, Telescopium, Montf. ; Cerithidea,
Swains. ; Lampania (Fig. 935) ; Pyrenella, Gray ; Sandbergia, Bosq.

Family 18. Aporrhaidae. Philippi.

Shell fusiform, turreted, or conical ovate. Aperture produced anteriorly in a canal.
Outer lip expanded in a wing-like or digitiform fashion, or thickened. Operculum horny.
Marine. Jura to Recent ; maximum in Jura and Cretaceous.

Alaria, Morris and Lye. (Figs. 936-938). Shell turreted; aperture
with long or short canal. Outer
lip not overriding the last whorl,
digitated or winged. Spire and

FIG. !)3(3.
Alaria myurus, Deslongch.
Lower Oolite ; Bayeux,
Calvados.

FIG. 937.

Alaria arniata, Morris
and Lye. Great Oolite ;
Minchinhampton, Eng-
land.

FKI.

FIG. 938.

Alaria (Anchura) cari-
nata, Mant. Gault ;
Folkestone, England.

body whorl often retaining traces of apertures at earlier stages.
Jura and Cretaceous.

Sub -genera: Dicroloma, Gabb ; Anchura, Conrad
(Fig. 938). Jura and Cretaceous. Diempterus, Piette.
Jura.

Spinigera, d'Orb. (Fig. 939). Whorls keeled
and ornamented with two opposite rows of spines.
Jura.

Aporrhais, da Costa (Chenopus, Phil.), (Figs.
940-942). Like Alaria, but margins of aperture
elongated posteriorly in a canal, which remains

Spinigera semicari-
nata, Goldf. sp. Callo-
vian ; Montreuil-Bellay,
Maine-et-Loire.

Very abundant in

FIG. 040.

Aporrhais (Dimor-
i) calcarata,

owb. Upper
nd ; Black-

FIG. 942.

Aporrhais (Lispodestlies) Reussi, Geinitz var.

Aporrhais tridttctylus, A. Braun. Oligo- Greensand ; Black- megaloptera, Reuss. Planer; Postelberg,
cene ; Hackenheim, near Creuznach. down, England. Bohemia.

either attached to the spire, or extends free from the same. Outer lip expanded,
digitated, or lobed. Jura to Recent.

SUB-ORDER B

PLATYPODA

471

Sub-genera: Alipes, Conrad; Arrhogcs, Tessarohts,

fnft/msf/i-int.*, Mii/tifif>;-ii, Piette ; Fterocerel/ii, Meek ; />/,/«/,
Lispodesthes, White (Fig. 942). Jura and Cretaceous.

Gabb ; C>jr(itosijihon, <;ill ;
^, St. Canhwr (Fig. 941);

Family 19. Strombidae. d'Orbigny.

Shell conical, turreted, or fusiform, with acuminate spire. Aperture canaliculate;
outer lip often expanded, anteriorly ivith an emaryination.
Operculum W////. .lura !•• l!.-n-nt.

Strombus crassilabrum, Zitt.
Cretaceous ; St. Gilgen, Austria.

Gosau-

FIG. 943.

Harpagodes oceani, Bnm^t.
Kinimeridgian ; Lindner Berg,
near Hannover.

Although the shells of
this family are excessively
variable, the animals them-
selves exhibit great uni-
formity of structure.

Harpagodes, Gill (Fig.
943). Spire short, body

whorl very large. Canal long, reflected. Outer margin produced
in a number of tubular spinous processes, the posteriormost of which
rests against the spire and extends nearly to the apex. Jura and
Cretaceous.

Pterocera, Lam. (Heptadactylus, Klein). Spire short ; canal bent
sideways. Outer margin wing-like, with tubular spinous processes,
beneath the most anterior of which is a deep notch. Recent.

Pterodonta, d'Orb. ; Thersitea, Coq. ; Pereiraea, Crosse. Miocene.
Strombus, Linn. (Oncoma, Mayer), (Fig. 944). Shell ovoid,
tuberculose or spinose, solid ; spire with several whorls ; body
whorl very large. Aperture elongate, obliquely truncated and
channelled anteriorly, canaliculate posteriorly. Outer margin
dilated in wing-like fashion, usually thick, often produced behind,
sinuate and sometimes channelled in front. Columellar border
simple, enamelled. Cretaceous to Recent.

Pugnellus, Conrad ; Cretaceous. Struthiolaria, Lam. ; Tertiary
and Recent.

Seraphs, Montf. (Terebellum, Lam.), (Fig. 945). Shell elongate,
sub-cylindrical ; spire short, summit obtuse. Body whorl very
large, smooth or striated. Aperture longitudinal, narrow posteriorly, and slightly

Fl.i. !».

Seraphs so pit urn,

472

MOLLUSCA

SUB-KINGDOM VI

dilated anteriorly ; canal short. Outer margin thin, simple, obliquely truncated

anteriorly, sometimes prolonged in

the spire posteriorly by a callosity.

Columellar border smooth, straight.

Tertiary and Recent.

Rostellaria, Lam. Spire high,

whorls smooth. Aperture produced

anteriorly in a beak-like canal, and

continued posteriorly as a narrow
channel resting on the
spire. Outer margin
with denticulate pro-
cesses, notched anteriorly.

Late Tertiary and 4, Rimella fissurella, Lam.
-p Calcaire Grassier ; Damery,

-nt. near Epernay. B, RL Barton -

Hippochrenes, Montf.
(Orthauiax, Cyclolomops,

Gabb), (Fig. 946). Like the last, but outer
margin expanded in wing - like fashion, and
destitute of processes. Upper Cretaceous and
Eocene.

Rimella, Agassiz (Isopleura, Meek), (Fig. 947).
Surface cancellated. Outer lip with thickened
margin, entire or crenulated. Upper Cretaceous
to Recent.

Family 20. Columbellariidae. Fischer.

Shell thick, elongated oval, with short conical
spire, and large, spirally ribbed, frequently can-
cellated body whorl. Aperture narrow, anteriorly
with short canal, and posteriorly with a canal
directed obliquely outwards. Inner Up callous,

outer lip often thickened, denticulated, or somewhat reflected outwardly. Jura and

Cretaceous.

Oolumbellaria, Rolle (Fig. 948). Surface covered with numerous spiral ribs, some-
times cancellated. Aper-
ture long and narrow,
broadening somewhat
anteriorly. Outer lip
denticulated internally,
not thickened, somewhat
reflected. Anterior and pos-
terior canals short. Upper
Jura.

Zittelia, Gemm. (Fig.
9 4 9). Like the last, but aper-
ture very narrow or cleft-like. Outer lip much thickened in the middle. Tithonian.

Columbellina, d'Orb. ; Cretaceous. Petersia, Gemm. (Fig. 950) ; Tithonian.

Family 21. Cypraeidae. Gray.

Shell ovate, convolute. Spire short, nearly or completely covered in the adult by the
very large body whorl. Aperture of equal length with the shell, narrow, anteriorly and

. 946.

Hippochrenes Murchisoni, Desh. Calcaire

Grassier ; Damery, near Epernay.

FIG. 948.

Columbellaria coral-
Una, Quenst. sp.
Coral- Rag ; Nattheim.

FIG. 949.

Zittelia crassissima,
Zitt. sp. Tithonian;
Stramberg.

Fio. 950.

Petersia costata,
Gemm. Tithonian ;
Palermo.

SUB-ORDER B

PLATYPODA

473

posteriorly produced in a usually short canal. Outer lip inflected. Operculum wanting.
Upper Jura to Recent.

Recent Gypraeidae, of which about 210 species are known, inhabit prinrijially tin-
wanm-r seas. They are often remarkable for their beautiful coloration, and .-HIM -t inn -
attain considerable size. Jurassic species are sparse; Tertiary ones rather more abundant.

Cypraea, Linn. (Fig. 951).
Ovoid, ventricose, enamelled,
smooth, lirate, or tuberculate ;
spire exposed or enveloped.
Aperture narrow, extending t In-
whole length of the shell, and
canaliculate at each extremity.
Inner lip and the inrolled outer
lip generally crenulate. Jura Flo 951

(G. titonica, Stefani) to Recent. ~ !'"•• 952.

Trivia, Gray (Fig. 952).

T ., , T i n ^c»c ! Weinheini,

Like the preceding, but smaller, near Alzey.

subexcisa,
raun. Oligo- Trivia affinix, l>n.j.

Erato laevix, Dmi.
Miocene ; NiederleiH,

Austria.

lt-°> *"M'

i ; Pont-
levoy, Touraine.

and sculptured with raised

transverse riblets. Anterior channel not prolonged, wide and slightly reverted.

Tertiary and Recent.

Erato, Risso (Fig. 953). Small, ovoid or pyriform, with short conical spire.
Aperture narrow. Inner lip smooth, except for anterior columellar folds ; outer lip
denticulate. Canal notch-like, broad. Cretaceous to Recent.

Family 22. Ovulidae.

Like the Cypraeidae, except that the spire

FIG. 954.
Gisortia tuberculosa, Duclos. Lower Eocene ; Cuise-la-Mothe.

ture anteriorly and posteriorly with a short canal.
Goldf. sp.

Pedicularia, Swainson. Miocene to Recent.

is convolute instead of produced and
covered, and the marginal teeth
of the radula are peculiarly
modified. Tertiary and Recent.

Ovula, Brug. Shell ovate
or fusiform, the spire completely
enveloped. Aperture produced
anteriorly and posteriorly as a
canal. Inner lip smooth ; the
outer inflected, smooth, or den-
ticulated. Tertiary and luvmi.

Gisortia, Jousseaume (Fig.
954). Large, thick - shelled,
ovate, with short convolute
spire. Surface typically keeled
or coarsely tuberculate. Body
whorl with a blunt ridge ; aper-
Eocene. G. (Strombus) gi<j<int"i.

Family 23. Cassididae. Adams.

Shell thick, inflated, globularly ovate, sometimes varicose; spire short, body whorl
very large. Aperture narrow, elongate, anteriorly with short canal. Inner lip resting on
an extensive callus, sometimes granulated or wrinkled. Outer lip more or less thickened.
Operculum horny, with marginal nucleus. Marine. Upper Cretaceous to Recent.

474

MOLLUSCA

SUB-KINGDOM VI

Gassidaria, Lam. (Morio, Montf. ; Galeodea, Link.), (Fig. 955). Shell ventricose,
not varicose. Canal long, twisted, reverted, or bent sidewise. Inner lip greatly

expanded, outer lip
reflected, often
crenulate. Colu-
mellar border
plicate. Upper
Cretaceous to
Recent ; maximum
in Eocene.

S u b - g e 11 11 s :
Sconsia, Gray (Fig.
956). Last whorl
with varix ; canal
short and straight.
Upper Cretaceous to
Recent.

FIG. 955.

Cassidaria carinata,
Lam. Calcaire Gros-
sier ; Grignori.

FIG. 956.

Cassidaria (Sconsia)
ambigua, Solander sp.
Oligocene ; Lattorf,
near Bernburg.

Cassis saburon, Lain. Mio-
cene ; Gainfahrn, near Vienna.

Cassis, Lam.

(Fig. 957). Shell ovoid, ventricose, having irregular varices. Spire short, aperture
elongate. Outer lip thickened, reflected, usually denticulate in the interior. Inner
lip callous, expanded, denticulate, wrinkled, or granulate.
Canal very short, broad, sharply recurved, directed upward
posteriorly. Tertiary and Recent.

Family 24. Doliidae. Adams.

Shell thin, inflated. Spire very short, body whorl very large,
longitudinally ribbed or cancellated. Aperture wide, oval;
canal straight or curved. Operculum absent. Cretaceous to
Recent.

Dolium, Lam. Spirally ribbed. Outer lip notched in-
ternally ; canal short, obliquely directed. Cretaceous to
Recent.

Pyrula, Lain. (Ficula, Swainson), (Fig. 958). Spirally FlG> 958

ribbed, grooved, or cancellated. Aperture very wide; outer pyruiareticuiata,Lzm.*p.

lip sharp ; canal Miocene; Gruud, near

, j Vienna.

long, broad,

straight. Lower Cretaceous to Recent ;
maximum in Tertiary.

Family 25. Tritonidae. Adams.

Shell thick, ovate to fusiform, with
epidermis. Spire moderately high, whorls
varicose. Aperture with thickened outer
lip, and open, straight, or slightly bent
canal. Operculum horny, with marginal
nucleus. Cretaceous to Recent.

Tritonium, Link. (Triton, Lotorium,
F-960- Montf.), (Fig. 959). Spire elongated.

Ranella marginata, Brocchi, The varices do not run continuously
iocene ; Grund, near Vienna. ,, ,, , , r< -, -,-,

over more than a few whorls. Columella

and inner lip callous or granulated. Outer lip thickened internally and notched.
Cretaceous to Recent ; abundant in the Tertiary.

FIG. 959.

Oligocene ; Weinheiin,
near Alzey.

PLATYPODA

475

Itfstartris, Link. (Persona, Montf.). Tertiary and Recent.

lamella, Lain. (Fig. 960). Like Tritonium, but with two opposite varices, wliirh
are continuous over all the whorls. Tertiary and Recent.

Superfamily 4. EACHIGLOSSA. Gray.

Radula reduced to three teeth or to one tooth in a transverse series.

These are carnivorous marine forms, which have their initiation in the Mesozoic,
become somewhat numerous in the Cretaceous, and form an important element of the
Tertiary and Recent faunas.

Family 1. Columbellidae. Troschel.

Shell small, ovate to fusiform, covered with epidermis, imperforate. Aperture narrow,
canal short. Outer lip denticulated internally, thickened in the middle.
Tertiary and Recent.

The typical genus, Columbella, Lamarck (Fig. 961), attains its
maximum distribution in the Tertiary and Recent seas. It is divided
into a number of sub-genera.

Family 2. Buccinidae. Troschel.

Fio. 961.

Shell elongate-oval, covered with epidermis. Aperture wide, with Columbetki curta,
jthort canal. Outer lip sharp or thickened. Operculum horny. Cre- j^pugy, 'Transyi-
taceous to Recent. vania-

Buccinum, Linn. Inflated, smooth, or transversely ribbed. Spire moderately
high ; aperture wide ; canal short, wide, open. Outer lip sharp and thin, inner lip

somewhat callous. Distributed principally in waters of the more

northerly zones (B. undatum, Linn.). Fossil in the Crag and

Pleistocene.

Cominella, Gray (Fig. 962). Usually spirally ribbed. The last

whorl somewhat depressed l)eneath the suture, so that the aperture

forms a small groove

posteriorly. Outer lip

sharp or crenate intern-
ally. Upper Cretaceous

to Recent.

Pseudoliva, Swains.

(Fig. 963). Like the
last, but outer lip with a small basal
tooth or notch which corresponds to a
groove on the body whorl. Upper Cre-
taceous to Recent.

Pisania, Bivona (Pisanella, v. Kce.nen ;
Taurinia, Bellardi). Elongate-ovoid, spire
moderately high. Whorls smooth or
spirally striated. Outer margin thickened,
notched internally. Tertiary and Recent.
Pollia, Gray (Cantharus, Bolten ;
Tritonidea, Swains.), (Fig. 964). Oval,
inflated; spire and aperture of about equal length; surface usually spirally ribbed
and transversely folded. Columella often with weak transverse folds ; outer margin
thickened, crenate internally. Aperture posteriorly with a short canal. Tertiary
and Recent.

FIG. 90.'.

( 'ominella cassidaria,
A. firaun. Oligocene;
Hackenheini, near
Alzey.

Pseudoliva Zitteli, Petho.
Upper Cretaceous ; Fruska
Gora, Hungary.

964,

Pollia snblamta, Bast.
ap. Miocene ; Enzes-
feld, near Vienna.

476

MOLLUSCA

SUB-KINGDOM VI

Phos, Montf. Shell elongate, bucciniform, turriculate ; spire sharp, elevated,
whorls ornamented with prominent longitudinal costae, and less salient spiral threads

and sulci, often varicose. Aperture oblong ; outer
margin lirate within. Columella excavated,
plicate in front ; canal short, slightly twisted.
Tertiary and Recent.

Eburna, Lam. (Dipsaccus, Klein), (Fig. 965).
Resembling Nassa, but smooth, perforate, and \\itli
deeply incised sutures ;
outer margin sharp. Tertiary
and Recent.

Nassa, Martini (Fig.
966). Ovate, inflated. Aper-
ture with short, reverted
canal ; inner, lip callous,
expanded ; outer margin
usually crenate internally.

Sparse in Upper Cretaceous and Eocene, abundant in Miocene
and Pliocene ; living species exceeding 200 in number, and dis-
tributed in numerous sub-genera.

Cyclonassa, Agassiz ; Cyllene, Gray ; Truncaria, Adams ;
•Buccinopsis, Deshayes. Tertiary and Recent.

Chrysodomus, Swains. (Neptunea, Bolten). Elongate - ovoid,
inflated, sometimes sinistral, with rather short and sometimes
bent canal. Cretaceous to Recent. G. contrarius, Lam. Crag.

Siphonalia, Zemira, Metula,

Adams ; Euthria, Gray ; Hemifusus, Swainson (Fig.
967). Tertiary and Recent. Mitraefusus, Genea,
Bellardi. Neocene.

Melongena, Schum. (Pyrula, Lam. p.p. ; Myristica,

caronis,

Brongt. sp. Eocene ;
Ronca, near Vicenza.

clathrata
Pliocene
Larniano, Tuscany.

PlO, 968.
Melongena cornutc, Agassiz. Miocene ; Bordeaux.

FIG. 9fi9.
Tudicla rusticula, Bast. sp. Mio-

cene ; Grund, near Vienna.
Swains.), (Fig. 968). Pyriform, inflated, with short spire. Body whorl large,

RUB-ORDER B

PLATYPODA

477

longitudinally striau-d and beset with nodes or rows of spines. Inner lip smooth;
aperture gradually becoming merged into the short and wide
canal. Tertiary and Recent.

Fulgur, Montfort (Busycon, Bolten). Tertiary and Recent.

Tudicla, Bolten (Fig. 969). Resembles Fulgur, but has a
-traight and very long canal; inner lip with a fold. ( 'n-iarc. in-
to Recent.

Strepsidura, Swains. (Fig. 970). Spire short; body whml
in Hated, transversely ribbed; canal curved. Eocene and Miocene.

Fio. 970.

Strepsidura ficulnea,
i.am. CalcaireOroMier;
, m>ar Epernay.

Family :i. Muricidae. Try on.

Shell thick. Spire moderately high; whorls ivith transverse
swellings, ribs, or folia, and frequently spinose. Aperture rounded or oval ; canal more
or less elongated, wholly or partially covered by margins of the inner and outer lips.
Opereulwn horny. Cretaceous to Recent.

Mitrcx, Linn. (Figs. 971-973). Shell rounded, spire prominent. Surface with at
least three, often more than three varices or transverse rows of spines or nodes on each

whorl. Aperture ovate ; inner lip smooth, outer lip
thickened. Canal much prolonged, partially closed,
usually spinose. Cretaceous to Recent.

Fio. 971.

Fit;. 973. Fio. 974.

'''"'• 972> Mum (I'tfronotus) T)i,<^''» 1»l>if,-r.

tirex spinicosta, Bronn. tricarinatiis, Lam. Montf. Calraiiv

/, Midit. Miocene ; Baden, near Eocene ; Damery, near Gmssifi •; Crii;-

Miocene] Gainfahrn', near Vienna. Vienna. Epernay. non, near I'aris.

Sub-genera: Haustellum, Klein; fthinacantha, Adams; Chicoreus, PhyJlonotus (Fig. 971),
Montfort; Pteronotus, Swainson (Triplex, Perry), (Fig. 973); Ocinebra, Leach, etc.

Typhis, Montf. (Fig. 974). Like Murex, but with hollow spines. Canal short,
completely closed. Upper Cretaceous to Recent.

Trophon, Montf. Spire high. Longitudinal ribs replaced by thin lamellae.
Canal open, somewhat curved. Tertiary and Recent.

Family 4. Purpuridae. Gray.

Shell thick, usually ovoid; spire short, body whorl large. Aperture wide, inner lip
and columella more or less flattened ; canal short. Operculum horny. Cretaceous to
Recent.

Purpura, Brug. (Fig. 975). Imperforate ; body whorl with transverse ribs or
nodes. Aperture oval, columella flattened, smooth. Tertiary and Recent,

478

MOLLUSCA

SUB-KINGDOM VI

Rapana, Schum. (Fig. 976). Like the preceding, but perforate,
expanded. Cretaceous to Recent.

Lysis, Gabb ; Stenomphalus, Sandberger.
Cretaceous and Tertiary.

Sistrum, Montf. (Ricinula, Lam.) ; Mono-
ceros, Lam. ; Concholepas, Lam. ; Cymia,
Morch, etc. Tertiary and Recent.

Family 5. Fusidae. Tryon.

Shell turreted, fusiform or ovoid, generally
without varices. Canal more or less elongated.
Inner lip smooth, or with weak columellar
folds ; outer margin thin. Operculum horny.
Jura to Recent.

These shells are sparse in the Upper Jura

Inner lip callous,

FIG. 975.
Purpurct exilis,

and Cretaceous, but abundant in the Tertiary Partsch. Mio-

mi • i T/«. T -i cene ; Mollers-

and Recent. The animal diners but little dorf, near Vienna.

FIG. 976.

Rapana laxecarinuta, Micht,
Oligocene ; Santa Giustina,
Italy.

from that of the Buccinidae and Muricidae.

Fusus, Lam. (Coins, Humph.), (Fig. 977). Shell narrow, elongate ; spire acuminate.

Aperture ovate ; canal very long, straight, open.
Outer margin thin, sometimes crenulate, and
often striate within ; columella smooth. Rare
in Upper Jura and Cretaceous, very profuse in
Tertiary and Recent.

Clavella, Swains. (Cyrtulus, Hinds), (Fig.
978). Thick-shelled, smooth, or with fine spiral
striae. Body whorl
suddenly contracted
anteriorly. Canal
very long, straight.
Common in Eocene ;
rare Neocene and
Recent.

Sycum, Bayle
(Leiostoma, Swains.),
(Fig. 979). Spire
short ; body whorl
inflated, smooth,
somewhat flattened
below the suture.
Inner lip smooth ;
canal straight.
Common in tin-

.. <>7s.

FIG. 977.

ng

Brocchi. Miocene ;
Baden, near

Vienna.

rare in

('li/rr//ii Inngaevus, Lam.
Eocene ; Damery, near
Epernay.

Sycum bulbiformis, Lain. Cal-
caire Grossier ; Grignon, near
Paris.

Eocene ;
Miocene.

Fascio I aria,
Lam. (Fig. 980).

Like Fusus, but distinguished in general by having a shorter spire, more inflated
body whorl, a wider and more sinuous or flexuous canal, and in that the anterior-
portion of the columella has two or three oblique plications. Cretaceous to
Recent.

Latirus, Montf. (Fig. 981). Shell fusiform, turreted ; spire costate. Aperture

RUB-OKI 'Kit !'•

PLATYPODA

179

l-'i.i. 981.

Latirus cw//V "/"'">,
d'Orb. sp. Miocene ;
l.;ipui:y, Transylvania.

oblong, outer margin relatively thin, crenulate ; columellar border slightly twisted,

with two or three small obliijin- plait-
anteriorly; sometimes umbilirate. Cre-
taceous to Recent.

Pisanella, v. Koenen. Oligocene.
Peristemia, Murrh ; Leucozonia, (Jray.
'IVrt iai-y and Recent.

Family 0. Turbinellidae.

Shell similar to those of the preced-
ing family, but with strong, horizontal
columellar folds. Tertiary and Recent.

Turbinella, Lam. (Mazza, Adam- :
Mazzalina, Conrad). Thick - shelled,
ovate-conical, smooth ; spire short and blunt, body whorl
large ; canal straight, elongated. Eocene to Recent.

Family 7. Volutidae. Gray.

Shell thick, ovate to fusiform, dull or lustrous. Spire
short or long, body whorl large. Aperture elongated, with a
short canal or notch ; inner lip with
columellar folds. Operculum usually
absent. Cretaceous to Recent.

This family, as here defined, contains
genera distributed by malacologists
amongst several families — Marginel-

lidae, Mitridae, and Volutidae — all of which are characterised by
the strong development of columellar folds ;
but it is likely that this structure originated
independently in several phyla at intervals
remote from one another. The initiation of
well - marked genera with Volutoid plaits
occurred in the Cretaceous. Subsequently their
number increased, and a great many generic
types became differentiated. The phylogeny
of Tertiary and Recent forms has been ably worked out by Dall.1

Marginella, Lam. (Fig. 982). Shell oval or oblong, smooth,
glistening. Spire short; aperture narrow, slightly canaliculate
anteriorly. Columella with three or four oblique folds of about
equal size ; outer margin frequently thickened and dentate.
Tertiary and Recei t.

Mitra, Lam. (Fig. 983). Fusiform to elongate - oval, solid;
spire high, acuminate ; aperture narrow, channelled anteriorly.
Columella with numerous oblique folds, the posterior plaits being
FIG. 983. often the strongest. Outer margin commonly thickened, and

fusiformis, smooth internally. Abundant in the Tertiary and Recent.

Turricula (Klein), Adams. Like the last, but shell transversely

FIG.

Fasdolaria Tarbellinina,Gra.t.
Miocene ; Gnmd, near Vienna.

IM.;. ;>S-2.

rginella cr/i.^n'n.
Calcaire Gros-
Chaumont, near
2/i-

Brocchi.
Rhodes.

Pliocene ;

ribbed. Cretaceous to Recent.

1 Bull. Museum Comp. Zoology, vol. XVIII., 1889 ; Proc. U.S. Nat. Museum, vol. XII., 1890 ;
Trans. Wagner Free Inst. Sci. Philad., vol. III., 1890.

480

MOLLtJSCA

SUB- KINGDOM VI

FIG. 984.

' Strigatella labratula,
Lain. sp. Eocene ;
Grignon.

Strigatella, Swains. (Fig. 984) ; Cylindromitra, Fischer (Cylindra, Schum.) ; Ira-
bricaria, Schum. ; Volutomitra, Gray. Tertiary and Recent.

Lyria, Gray (Fig. 985). Elongate - oval, transversely ribbed. Aperture narrow.
Columella anteriorly with two much compressed and very large plications, behind

(above) which are numerous weaker ones.
Outer margin thickened. Tertiary and Recent.
Halia, Risso (Priamus, Beck). No columellar
folds. Pliocene and Recent.

Volutilithes, Swains. (Fig. 986). Shell
fjisiform, spire elongate -conical ; nucleus small,
rising to a more or less acute apex. Whorls
costate, typically spinose. Aperture anteriorly
with short broad canal ; columellar folds vari-
able, several in number, those toward the
anterior being generally the most pronounced.
Abundant in the Cretaceous, Eocene, and
Oligocene ; only one recent species.

Allied genera and sub -genera : Gosavia,
Stol. ; Leioderma, Rostellites, Conrad ; Voluto-
derma (Fig. 987), Volutomorpha, Gabb. Cre-
taceous.

Athleta, Conrad. Spire short, body whorl
inflated, posteriorly with a row of spinous
nodes. Inner lip callous, much expanded ;
columella anteriorly with three strong trans-
verse folds, behind (above) which follow a few
bicormia, weaker ones. Outer margin thickened. Eocene
and Miocene.

Valuta, Linn. (Fig. 988). Shell elongate-
oval or fusiform, solid, broad, and with elevated, turbinate, smooth nucleus. Spire
short, longitudinally plicate, the folds being
elevated into obtuse tubercles on the base of
the whorls. Aperture narrow, canaliculate
behind and broad in front ; inner margin
often covered by a thin callus. Columella
carrying many plaits, four or five of which
are prominent, the remainder much smaller.
Tertiary and Recent.

Sub-genera : Fulgaria, Schum. ; Scapha, Gray
(Fig. 988) ; Volutella, d'Orb. ; Aurinia, Adams
(Volutifmus, Conrad), etc.

Musica, Humphrey. Spire short, nucleus
small. Aperture narrow, inner lip callous,
with numerous transverse folds ; outer margin
thickened. Tertiary and Recent. toawvS^eiowata' FlG< m

Cymbium, Klein (Yetus, Adams ; Melo, d'Orb. Gosau-Cre- Valuta (Scapha) vmricina,

TT i \ r\ L -r> taceous • St Gil<*en Lam. Calcaire Grossier ;

Humph.). Cretaceous to Recent. Austria Dainery, near Epernay.

FIG. 985.

Lyria modesta, A.
Braun. Oligocene ;
Weinheiin.

FIG. <

Volutilithes
Lam. Eocene ; Cour-
tagnon, near Epernay.

Family 8. Harpidae. TroscheL

Spire depressed ; body whorl inflated, with sharp, uniformly spaced transverse ribs.
Aperture ivide, with short, broad canal. Inner lip callous. Operculum absent. Tertiary
and Recent.

sr r,-<>iu>KK i:

PLATYPODA

Tin- typical genus ///»/•/»!. Lmi. .>'///»/. Mavn- , Kig. 989),
to tin- present time.

> HufjHipaiK, Mayer (Cryptochorili, M«'i-«-li .

Kit:. 1)90). Elongate-oval ; spire short, body

whoi-1 large, smooth, lustrous. Apcrimv

with sliort recurved canal; inner lip callous.

Common in the Eocene.

Family 9. Olividae. d'Orbigny.

Shell elongate-oval to sub-cylindrical, solid,
smooth, and glistening. Spire short; body
whorl very large. Aperture narrow ; outer
lip sharp; columella anteriorly with <u> out-
wardly reflected callus. Canal very short.
Cretaceous to Recent.

//('»•;>" iiiutica, Lam.
('all-aim Grossier;
Grignon.

Fi.:. '.".'O.
Iliii'ji»i>.-i.i .*t i

Lam. sp. Calcaire
Grossier; Da in cry,
near Epernay.

FIG. 991.

Oliva cfofvta, Lam.
Miocene ; Dax, near

cene ; Steinabrunn.

Oliva, Brug. (Fig. 991). Shell sub-
cylindrical ; suture line marked by a deep groove. Columellar callus obliquely folded.

Cretaceous to Recent.

Ancilla, Lam. (Ancillaria, Lam.), (Fig. 992).
Shell oblong, occasionally acuminate. Suture
usually covered over by a lustrous enamel -like
callus. Aperture somewhat broadened anteriorly ;
columellar callus slightly twisted. Cretaceous to
Recent.

Superfamily 5. TOXOGLOSSA. Troschel.

Radula typically with only two arrow-shaped
teeth in each transverse row, although occasionally
as many as five teeth are developed. Shell similar
t0 that of the Rachiglossa.

This group is closely allied to the Rachiglossa, from which it probably became
differentiated in the Cretaceous. The Tertiary and
Recent species are excessively profuse. All are
carnivorous and marine.

Family 1. Cancellariidae. Adams.

Shell oval to turreted. Spire acuminate; body
whorl inflated ; surface transversely ribbed and in most
cases cancellated. Aperture with short canal or notch ;
columella with several strong oblique folds, outer lip
grooved internally. Upper Cretaceous to Recent.

The typical genus Oancellaria (Fig. 993) attains
a maximum distribution in the late Tertiary and
Recent.

Family 2. Terebridae. Adams.

FIG. 993.

CanceUnrtu con-
irlliifii, Linn. Min-
ct'iio ; (Jainfahrn,
near Vienna.

lerebra iii'iuni imtii ,

Borson. Miocene;
near Vienna.'

Shell turreted, slender, acuminate, with small body whorl. Avert nn-

7 j-7^7 77 7 »• - i

ova^ or quadrilateral; canal short, curved; outer hp sharp. Oper-
culum horny. Tertiary and Recent.

Of the two leading genera, Terebra, Lam. (Fig. 994), and Acus, Humphr., the tii>t

VOL. I Or

482

MOLLUSCA

SUB- KINGDOM VI

is characterised by a line running parallel with the suture, and creating a narrow
suture band.

Family 3. Pleurotomidae. Stoliczka.

Shell fusiform) with moderately high spire. Aperture elongated, produced anteriorly
in a longer or shorter canal. Outer lip with a slit or notch below the suture. Operculum
horny, sometimes absent. Cretaceous to Recent.

Upwards of 700 recent and 1000 fossil species have been described, of which 28
are Cretaceous.

Pleurotoma, Lam. (Figs. 995-998). Shell turriculated, spire long. Body whorl of
nearly equal length with the spire ; canal long and straight ; columellar margin

A V C A

FIG. 995.

A, Pleurotoma notata, Brocchi var. ( = P. monilis,
Hoernes). Miocene ; Baden, near Vienna. B, P. (Surcula)
Lamarcki, Bell. Miocene ; Baden, near Vienna. C, P.
(Surculct) belgica, Nyst. Oligocene ; Weinheim, near
Alzey.

FIG.

A, Pleurotoma (Genota) ramosa,
Bast. Miocene ; Grund, Hungary.
B, P. (Cryptoconus) filosa, Lam.
Calcaire Grossier; Grignon, near
Paris.

smooth. Outer margin of the aperture with a narrow, deep sinus, situated at or some

distance below the suture.
Operculum pointed ovate,
with apical nucleus. Cre-
taceous to Recent.

Sub-genera : Surcula
(Figs. 995, B, G] ; Genota,
Adams (Fig. 996, A); Doli-
chotoma (Fig. 997), Oligo-
toma, JRoualtia, Bellardi ;
Cryptoconus, v. Koenen
(Fig. 996, B} ; Drillia (Fig.
998), Beta, Gray ; Lachesis,
Risso, etc.

Clavatula, Lam. (Fig.
9 9 9). Differs from Pleuro-
toma in that the outer
margin is cut by a shallow
triangular notch, and
nucleus of operculum is
situated in the middle of
Sub-genera : Pseudotoma, Clinura,

FIG. 997.

Pleurotoma (Dolicho-
toma) cataphracta,
Brocchi. Miocene ;
Baden, near Vienna.

FIG. 998.

Pleurotoma (Drillia)
incrassata, Duj. Mio-
cene ; Steinabrunn,
near Vienna. 2/j.

FIG. 999.
Clavatula asperulata,

the anterior margin.
Bellardi.

Cretaceous to Recent.

SDB-CLA» I!

PLATYPOI )A— K I T 1 1 Y N KM 1 A

4*3

Borsonia, Bellardi (Fig. 1000). Outer margin with a shallow n<it<-h ; canal long
and straight; columella with one or two folds; operculum unknown. Eocene to
Recent.

Mangilia, Risso (Figs. 1001, 1002). Small, fusiform, imperforatc, ami typically
with longitudinal costae or >w»-]Iings. Aperture commonly narrow, with a short,

IMC:. 1000.

Borsonia Deluci,
Nvst. Lower Oligo-
cene; Lattdorf, near

FIG. 1001.

Mangilia angusta,
Jan. Pliocene ;
Occiano, near Pisa.

FIG. 1002.

A, Mangilia (Clathur-
ella) stroinbilltis, Duj.
Miocene ; Kienberg,
near Vienna. /-', M.
(Homotoma) retinilntu,
Brocchi. Pliocene;
Sassnola, near Modena.

Fi.;. 1003.

/mini) r a I jn i- a 1 a ,

Brocchi. Pliocene;
Siissnola, near
Modena.

truncated canal ; inner margin varicose ; sinus near the suture. Outer margin usually
somewhat thickened, posteriorly with shallow notch. Tertiary and Recent,

Allied genera are the following : — Clathurella, Carp. (Fig. 1002, .4) ; Homotoma
(Fig. 1002, B) ; Atoma, Bellardi ; Daphnella,
Hinds, with sub-genus Raphitoma, Bellardi (Fig.
1003); Eucythara, Fischer, etc.

Family 4. Oonidae. Adams.

Shell convolute, turbinate, or sub - cylindrical,
generally smooth. Spire short, conical or flattened.
Aperture long, narrow, anteriorly notched. Outer
lip sliarp, sometimes with an anal sinus below the
suture. Columella smooth. Operculum horny.
Cretaceous to Recent.

This family is now enjoying its acme of
development, having entered upon its ascendency
during the Tertiary. The typical genus Conus,
Linn. (Fig. 1004), is divided by malacologists
into numerous sub -genera, connected with one
another by intermediate forms,
the Cretaceous.

Conorbis, Swains. Characterised by a high
spire, and a curved, outer lip, which is deeply notched posteriorly. Eocene and
Oligocene.

FIG. 1004.

A, Conus jwndtrostis, Brocchi. Miocene ;
It is initiated in Lapugy, Transylvania. Ji, r. petH

Desh. Calcaire Grossier ; Griguon, near
Paris.

Sub-Class 2. EUTHYNEURA. Spengel.

Gastropods in which the visceral nerve commissures are not crossed, but form a
loop ; the sexes are united (hermaphrodite) ; and the heart is often in front of the gill.
Shell spiral or saucer -shaped, frequently vestigeal or absent ; operculum generally wanting.
Radula generally multiserial.

484 MOLLUSCA SUB-KINGDOM vi

Order 1. OPISTHOBRANCHIA. Milne-Edwards.

Marine, water-breathing forms, either naked or shell-covered, in which the gills are
placed behind the heart and lie free on the back or side ; or true gills may be absent,
being replaced by secondary or false gills. Heart with a single auricle.

The Opistliobranchiates, unlike the Streptoneura (Prosobranchiates), send the blood
into the heart from behind, instead of from the anterior side. The gills, in the form
of a more or less branched plume, lie on the right side, or are replaced by false gills
not homologous with the ctenidium, arranged either in two rows on the back, or
wreath-like around the anus. The gills are often covered by the mantle, and some-
times become completely atrophied. The radula generally resembles that of the
Pulmonates. The body and nervous system usually exhibit bilateral symmetry.

Two sub-orders are recognised in the recent fauna : (1) Nudibranchiata, in which
a shell is absent, except during the larval stage, and the ctenidium is replaced by false
gills ; abundantly distributed in all seas at present, but owing to their perishable
nature are unknown as fossils ; and (2) Tectibranchiata, in which a mantle, shell, and
ctenidium or true gill is developed. To these it will be convenient to add a third
group, Pteropoda, which is here given nominal rank as a sub-order ; as well as a
fourth, Conularida, to contain Palaeozoic forms of doubtful affinities.

Sub-Order A. TECTIBRANCHIATA.1

This group, briefly defined above, has fossil representatives as early as the
Palaeozoic. During the Mesozoic, a few genera now extinct were very profuse. Most
of the Tertiary species belong to existing genera.

Family 1. Actaeonidae. d'Orbigny.

Shell ovate, with exposed spire, the surface usually grooved and punctured, sometimes
smooth. Aperture long, rounded below; columella generally twisted, or with folds.
Operculum paucispiral. Carboniferous to Recent.

Solidula, F. de Waldheim (Buccinulus, Adams ; Dactylus, Schum.). Ovate or
oblong, compact, solid, with a short conic spire. Columella bearing two plications, the
anterior prominent and bifid, the posterior comparatively inconspicuous when the shell
is entire ; between them the columella is spirally excavated. A few
ill-defined species from the French Eocene and Miocene, one from the
Australian Pliocene, and numerous recent, tropical species are known.
Tornatellaea, Conrad (Fig. 1005). Differs from Solidula and
Actaeon in the more anterior disposition of the two columellar
plications, in the marked depression on the anterior portion of the
aperture, and in the greater thickness of the shell near the outer
Tornatellaea 'simu- ljorder °f tne aperture, which, is frequently crenulated. Base of Jura
lata, Sowb. oiigo- to M.iocene ; widely distributed. Type — T. bella, Conrad. Sub-
nwBernbw£°rf> genus— Triploca, Tate. Eocene ; Australia.

Actaeon, Montf. (Tornatella, Lam. ; Speo, Risso ; Kanilla, Silver!.).
Oval, spirally punctate-striate, with conic spire. Protoconch not very prominent ;
nucleus sinistral. Columella thick, with one strong, spiral, slightly oblique plication.
Upper Cretaceous to Recent.

1 Literature (see also preceding bibliographies) :
Cossmann, M., Essais de Paleoconchologie comparee, I., 1895.

Pilsbry, H. A., Monograph of Recent Tectibrauchiata, in Manual of Conchology, vols. XV., XVI.
1894-95.

SUH-ORDER A

TECTIBRAXCHIATA

485

Adelactaeon, Cossm. (Myonia, Adanis). Protocondi with sini.-tral nucleus ; not very
Whorls decussated by fine stria.-, growth- lines inconspicuous. Coluinclla
slightly excavatfl, ami < arrving a small but well-marked plication.
Miocene of Franrt- ami < ii-nnany, and Rorriit.

Actaeonina, d'Orb. (Orthostoma, Desk), (Figs. 1006, 1007).
Slii-11 ovoid to fusiform, usually smooth, rarely spirally striated.

PlO. 1007.

Actaeonina myosotis,
Buv. Coral-Rag; St.
Miliifl. Mruse. 2/i
(after Buvignier).

FIG. 1006.

Actaeonina Dormoi-
siana, d'Orb. Coral-Rag;
Valtiu, Aiii.

FIG. 1008.

Cylindrites acutus,
Sowb. sp. Great
Oolite; Minchin-
hainpton, England.

FIG. 1009.

Actcteonella (jitjantea, Sowb. Turonian ; Griin-
bach, I^ower Austria.

Spire conical, body whorl very large, narrowing toward the base. Columella straight,
without folds. Outer lip sharp. Carboniferous to Eecent.

Sub-genera : Euconactaeon, Conactaeon, Meek. Lias. Douvilleia, Bayle. Tertiary.

Cylindrites, Fer. (Fig. 1008). Cylindrical-ovoid with short' spire. Columella
with an anterior fold. Trias to Cretaceous.

Bullina, Fer. Jura to Recent. Cylindro-
hullina, v. Ammon. Trias, Lias. Etallonia,
Desh. Jura and Tertiary. Bullinula, Beck.
Jura to Recent.

Actaeonella, d'Orb. (Figs. 1009-1011).
Thick -shelled, inflated, smooth. Spire short ;
columella thickened anteriorly, 'vith three
sharp folds. Very profuse in the Middle and
Upper Cretaceous ; maximum distribution in
the Hippurite Limestone of the Alps.

Sub -genus: Volvulina., Stol. (Fig. 1011).
Like the preceding, but with insunken spire.
Cretaceous.

F>«:. 1011.

..... Ian;

Volvaria, Lam. Cylindrical, with in-
volute, concealed spire. Surface usually
spirally striated ; aperture narrow ; columella with four anterior plications.

Eocene.

•486

MOLLUSOA

SUB-KINGDOM VI

Family 2. Ringiculidae.

Inoperculate forms resembling Actaeonidae in having columellar folds. Cretaceous
to Recent.

Cinulia, Gray (Fig. 1012). Globose, inflated, spirally grooved or punctate. Spire
short ; aperture crescentic ; outer lip reflected and thickened. Columella and inner
lip with numerous transverse folds. Cretaceous.

Sub-genera : Avellana, Ringinella, d'Orb. ; Eriptycha, Meek ; Fortisia, Bayan. Eocene.

Ringicula, Desh. (Fig. 1013). Small, ovoid to globose, thick -shelled, with mamil-
lated protoconch. Spire short ; body whorl large, usually smooth. Aperture canali-

Fio. 1012.

A, Cinulia (Avellana) incrassata, Mant. sp. Gault ; Perte
du Rhone. B, C. (llinnhii'Jl,,) lachryma, Mich. Gault ;
Folkestone, England. C, C. (Eriptycha) decurtata, Zekeli.
Turonian. Gosau, Austria.

FIG. 1013.

Ringicula Hoernesi,
Seguenza. Miocene ;
Steinabrunn, near
Vienna.

culate posteriorly, excavated anteriorly. Columellar border thick and callous ; the
columella arched, and furnished with from two to four plications. Outer margin
usually very thick, reflected, and occasionally denticulated within. Cretaceous to
Recent.

Pugnus, Hedley. Cylindrical, with sunken spire. Recent.

Family 3. Akeratidae. Pilsbry.

Shell oval or cylindrical, thin and fragile, the spire low or concealed. Tertiary and
Recent.

Akera, Miiller (Fig. 1014). Thin-shelled, flexible, with exposed, truncated spire.
Whorls separated from one another by deep sutures. Sutures
deep and prominent ; outer lip separated from the spire.
Eocene to Recent.

Haminea, Leach. Oval, thin-shelled, brittle ; the spire
concealed. Tertiary and Recent.

FIG. 1014.

Akera striatella, Lam.
Oligocene ; Castel Gomberto,
near Vicenza.

Family 4. Hydatinidae. Pilsbry.

Globose or oval, with exposed, nearly level spire and tilted
nucleus. Jura to Recent.

Hydatina, Leach, Schum.
Pilsbry. Recent,

Jura to Recent. Aplustrum, Schum. ; Micromelo,

Family 5. Bullidae. Pilsbry (emend.).

Shell oval or sub-globose, involute, smooth. Spire sunken and concealed. Aperture
long, rounded anteriorly ; outer lip sharp. Marine. Jura to Recent.

sri:-()HDER A

TECTIBRANCHIATA

48'

Bulla, Klein (Fig. 1015). Oval, inllat.-d, with .sunken spire and perforate n\»-\.
A]>.-rture rounded posteriorly and anteriorly. Jura(?) to Recent.

Family 6. Tornatinidae.

Radula unarmed. Tertiary and Recent.

Tornatina, Adams (Fig. 1016). Cylindrical, with projecting
spire, and sinistral, tilted nucleus. Coluim-lla
bearing a single fold. Tertiary and Recent.

Retusa, Brown. Shell resembling Cylichna.
Tertiary and Recent.

Volvula, Adams (Volvulella, Newton). Fusi-
FIO. ioi6. form, the body whorl forming a point above the

spire. Eocene to Recent.

Tornatina exerta,
Desh. Oligpcene;
Jeurres, near Etampes
(after Deshayes).

um.

Hull, i itinpiilln, Linn
Asti, Italy.

Family 7. Scaphandridae.

Spire concealed ; radula with few teeth in a row. Trias to Recent.

Scaphander, Montf. (Fig. 1017). Shell sub-cylindrical, with epidermis, usually
spirally striated. Body whorl of enormous capacity, much dilated
anteriorly. Columella spiral, leaving a false umbilicus. Cretaceous
to Recent,

Atys, Montf. Cretaceous to Recent. Diaphana, Brown.
Tertiary and Recent. Smaragdinella, Adams.
Recent.

Cylichna, Loven (Bullinella, Newton), (Fig.
1018). Small, cylindrical, solid ; spire deeply
perforated at the summit ; body whorl covering
all the others. Aperture very narrow, outer
margin longer than the axis of the shell.
Columella thickened anteriorly and bearing a
small plication ; often umbilicated. Trias to Flf;- 1017

Recent.

FIG. 1018.

Cylichna conoiden,
Desh. Oligocene;
Weinheim, near Alzey.

Family 8. Philinidae.

Scaphander conicits,
Desh. Eocene ; Brack-
lesham, England.

Similar to Scaphandridae, but shell internal, loosely coiled, punctate. Cretaceous to
Recent.

Philine, Ascan. (Bullaea, Lam.), (Fig. 1019). Cretaceous to
Recent.

Family 9. TJmbraculidae.

FIG. 1019.
Shell orbicular, broad, Desh. Eocene.'

Shell limpet -shaped, with low sub -central apex, and sharp, thin
edges. Tertiary and Recent.

Umbraculum, Schum. (Umbrella, Lam.).

patelliform ; ornamented exteriorly with concentric lines of growth ; in-
ternal surface with concentrically undulating striae. Eocene to Recent.

Other families of Tectibranchiata, such as Aplysiidae, Pleurobranchidae, etc., are
represented in the recent fauna, but their thin, often membranous shells have not been
found fossil. The supposed Aplysias reported from the Pliocene by Philippi are
flakes from the interior of Pelecypod valves.

488 MOLLUSCA SUB-KINGDOM vi

Sub- Order B. PTEROPODA. Cuvier.1

Naked or shell-covered, hermaphrodite, pelagic Mollusca, without distinct head. Eyes
rudimentary, and foot replaced by two lateral, wing-like fins, situated on the anterior end
of the body. The gills are placed behind the heart.

The body of these free-swimming Mollusca is sometimes elongated, sometimes coiled
posteriorly in a spiral. In some instances it is covered by a thin transparent slid!
(Thecosomata), but oftener it is naked (Gymnosomata). The creatures associate in vast
swarms in the open sea, and rise to the surface toward nightfall. Their shells often
accumulate in prodigious quantities on the sea-bottom, forming calcareous deposits of
considerable magnitude.

Cuvier recognised the Pteropods as an independent class of Mollusca, having equal
rank with the Gastropods. The researches of Pelseneer, however, have shown that
they stand in about the same relationship to the Opisthobranchs as Heteropods do to .
the Prosobranchs. They are, in fact, Opisthobranchs which have become pelagic,
having the foot transformed into a bilobed swimming organ, and with a rudimentary
head. The structure of the head is very variable. The heart has only one auricle.
Many shell-covered forms (Limacinidae) develop a horny operculum, but others are
without it.

Fossil Pteropods similar to those now living occur somewhat sparingly in the
Upper Cretaceous and Tertiary. Argillaceous strata of Pliocene and Oligocene age
are occasionally highly charged with the remains of Cleodora ; these occur for the
most part, however, in a compressed and poorly preserved condition.

Pteropod-like shells are present in the Palaeozoic, appearing as early as the Lower
Cambrian (Conularia, Tentaculites, Hyolites), where they constitute an important part
of the fauna. These remains were assigned unhesitatingly to the Pteropods by
d'Archiac and de Verneuil, Sandberger, Barrande, and numerous other authors.
Xeumayr, however, and more recently Pelseneer, have urged strong objections against
their union with this group, although they have failed to suggest a more satisfactory
position for them in the zoological system. Neumayr's proposal to associate the
Palaezoic Tentaculites and Styliolas with Tubicolous Worms was rejected by Nicholson
after a microscopic investigation of their shell-structure. The hypothesis advocated
by Miller, Fleming, Hall, and more recently by Ihering, according to which Conularias
are Cephalopods akin to Orthoceratites, is utterly without any credible foundation.

1 Literature (see also preceding bibliographies) :

Sandberger, G., Die Flossenfiisser oder Pteropoda (Neues Jahrb. fii'r Mineral., pp. 8-25), 1847.
Barrande, J., Pugiunculus, ein fossiles Pteropoden-Geschlecht (Neues Jahrb. f'iir Mineral., pp. 554-

558), 1847 ; Systeme Silurien du centre de la Boheme, vol. III., Pteropodes, 1867.
Salter, J. W., Memoirs of the Geological Survey of Great Britain, vols. II., III., 1848, 1866.
Seguenza, G., Paleontologia malacologica dei terreni terziarii del distretto di Messina. Pteropodi ed

Eteropodi (Mem. Soc. Ital. Sci. Nat. Milano, vol. II.), 1867.
Karpinsky, A., Die fossilen Pteropoden am Ost-Abhang des Ural. (Mem. Acad. St. Petersburg, ser.

7, vol. XXXII., pp. 1-20), 1884.
Dollfus, G., and llamond, G., Liste des Pteropodes du terrain tertiare parisien (Mem. Soc. Malacol.

de Belgique, vol. XX.), 1885.
Walcott, G. I)., Contribution to Studies on the Cambrian Faunas of North America (Bull. U.S. Geol.

Survey, vol. IV., No. 30, pp. 125-146), 1886 ; The Fauna of the Lower Cambrian or Olenellus

Zone (Tenth Ann. Rept, U.S. Geol. Survey), 1890.
Pelseneer, P., Report on the Pteropoda (Report Challenger Expedition, Zoology, vol. XXIII.), 1888 ;

Bull. Soc. Beige de Geol. Palaeont. et Hydrol., vol. III. p. 124), 1889.
Blanckenhorn, M., Pteropoclenreste aus der oberen Kreide Nord-Syriens und aus dem hesseschen

Oligocan (Zeitschr. deutsch. geol. Gesellsch., vol. XLI. pp. 593-602), 1889.
Novdk, 0., Revision der palaeozoischen Hyolithiden Bohmens(Abhandl. bohm. Gesellsch. Wissensch. [7]

Bd. IV.), 1891.
Holm, G., Sveriges Kambrisk-Siluriska Hyolithidae och Conularidae (Afhaudl. Sver. geol. Under-

sokuing, Ser. C, No. 112), 1893.

SUB-ORDER B

It manifestly cannot be denied that Conularias and Hyolithes in particu!

size, shell structure, and probably also conditions of existence, diH'i-n-d r<>n-
-idrrably from recent Pteropods. But in spite of the diH'rn-in-cs so strongly
emphasised by Pelseneer, the fact remains that of all shell-covered or^ani-m-, they
approach the Pteropods most nearly, and cannot with propriety be ivt.-rn-d to any
other group of the Mollusca.

Family 1. Limacinidae. Cray.

Shell thin, spiral, sinistral, with vitreous, paucispiral operculum. Tertiary and
Recent.

The genus Limacina, Lam. (Spirialis, Eyd. and Soul. ; Embolux, Jeffreys), is of
sporadic occurrence in the Tertiary (Eocene and Pliocene). Valvatina, Watelet,
includes flat sinistral shells from the Calcaire Grossier of Paris, and Planorbella, Gabb,
contains similar forms from the Oligocene of San Domingo.

Family 2. Cavoliniidae. Fischer.

Shell symmetrical, thin, vitreous, ventricose, pyramidal, or conically tubiform, but not
spiral. Cretaceous to Recent.

Cavolinia, Gioeni (Hyalaea, Lam. ; Gamopleura, Bellardi), (Fig. 1020). Shell
globose, laterally keeled and slit, acuminate pos-
teriorly ; composed of two unequally arched pieces,
one of which projects helmet-like above the other.
Recent, and fossil in the Italian Miocene and
Pliocene.

Clio, Linn. (Cleodora, Peron and Lesueur ;
Balantium, Benson ; Flabellum, Poculina, Bellardi),
(Fig. 1021). Shell somewhat angular, compressed
dorso-ventrally, with lateral keels. A crest or rib
generally extends longitudinally along the back, and
usually projects. Upper Cretaceous to Recent. A

common fossil in the Pliocene of Monte Mario, near Rome, and the vicinity of Messina
and Turin ; also in the Oligocene of the Mayence Basin, and in the English Crag.

FIG. 1020.

A, Cavolinia (Hyalaea) trident" f", Korsk.
"5, (7, C. (Guinoplcurd*) tit":

FIG. 1021.

A, Cleodora pyramidata, Linn. Pliocene; Monte
Mario, near Rome. B, JMantium recurcu;-. \.
Adams. Recent. Animal with shell (after Adams).
C, Vaginella depressa, Daudin (Clewlora strait*
Desh.). Miocene ; Dax, near Bordeaux.

A, Styliola recta, Lesueur. Recent (after
Adams). B, Stuliola striatnl<>, Novak. !>'•-
vonian (Etage H); Hlubocep, Bohemia. 3/i-
C. Styliolfl davuku, Barr. Devonian (Kta-r H):
Hostin, near Prague, Bohemia. Several in-
dividuals on slate-fragment. Vi-

Sub-genus : Styliola, Lesueur (Creseis, Rang ; Crisia, Menke), (Fig. 1022). Shell conical,

490

MOLLUSCA

SUB-KINGDOM VI

straight, elongated ; surface smooth or faintly striated ; dorsal groove not parallel to axis of the
shell, but slightly oblique, with only the anterior extremity (which ends in a rostrum) in the
median line ; embryonic portion ends in a pointed apex. Tertiary and Recent.

In the Devonian of Bohemia, Nassau, Ural, and North America, great numbers of smooth,
circular, longitudinally striated tubes are occasionally met with, the posterior end of which is
inflated into a small bulb. Similar tubes have also been described by Blankenhorn from the
Cretaceous of Syria. None of these differ externally to any great extent from Clio or Styliola.

Vaginella, Daudin (Fig. 1021, (7). Shell long, ventricose, depressed; apex sharp-
pointed, constricted in front ; aperture slightly canaliculated and compressed laterally.
Cross-section elliptical. Upper Cretaceous to Eecent.

Cuvieria, Rang; Triplera, Quoy (Fibiella, O. Meyer). Tertiary and Recent.
Euchilotheca, Fischer. Eocene.

Sub-Order C. CONULARIDA. Miller and Gurley.

Palaeozoic forms of doubtful systematic position, resembling some recent Pteropoda,
but probably to be regarded as a parallel rather than as an identical group.

Family 1. Tentaculitidae. Walcott.

Thick-walled, tapering, elongate, conical tubes, having a circular cross-section, and
terminating posteriorly either acutely or in an embryonal bulb. Surface ornamented with
A B c parallel raised transverse rings. The apical portion of

the shell often filled with calcareous matter, or divided
off by transverse septa. Ordoviciaii to Devonian.

Tentaculites, Schloth. (Fig. 1023). This, tlie
solitary genus, is prodigiously abundant in the
Silurian and Devonian, tbe strata being sometimes
fairly charged with their remains. The shell is
composed of a compact outer layer, and an inner
layer made up of thin lamellae running parallel with
the external surface. The supposed Tentaculites
described from the Oligocene by Ludwig and Blanken-
horn are thin -shelled, transversely ribbed, conical
tubes, which probably belong in the neighbourhood
of Styliola or Euchilotheca.

FIG. 1023.

A , Tentaculites sccdaris,
Schloth. Erratic block of
Ordovician age ; Berlin. B, T.
ornatus, Sowb. Silurian;
Dudley, England. C, T.
acuarites, Richt. Silurian
concretion ; Thuringia. A
smaller individual contained
within the larger (after
Novak).

Torellellidae. Holm.

Family 2.

Thick-walled, smooth, transversely or longitudinally
striated, straight or bent tubes, acutely terminated pos-
teriorly, and without opercula. Cambrian to Silurian.

Torellella, Holm. Tubes strongly compressed, flattened at both ends, elliptical in
cross-section, and with fine transverse striae ; composed of brownish-coloured calcium
phosphate. Cambrian to Silurian ; Sweden.

Hyolithellus, Salterella, Billings, Coleolus, Hall, and Coleoloides, Walcott, from the
Lower Cambrian of North America, probably also belong here.*

Family 3. Hyolithidae. Nicholson.

Shell symmetrical, conical, or pyramidal, straight or sharply bent ; cross-section
triangular, elliptical, or lenticular ; one side often flattened, and the other arched or with

81 l: oKDER C

CONULARIDA

H blunt median keel. Surface smooth or in'tli inn', transverse striae, rarely longitudinally
^i i- i^t I'd or ribbed. Aperture coinylitihi <-l<>*> il I*,/ «,< operculum, the latter being semi-
i-finihtr, triangular, or lentifonn, >'•//// lateral nucleus, and concentrically x//-/'<//r*/.
( 'aiiiln-ian to Permian.

The shells belonging here are of large size, and composed of calcium carbonate
The posterior portion is often divided off by
transverse septa.

According to Holm, the typical genus Hyolithes,
Eichwald (Theca, Sowb. ; Pugiunculus, Barr), (Fig.
1024), is divisible into two sub-genera. One of
these, Orthotheca, Novak, contains forms with an
abruptly truncated anterior end ; and in the
other, Hyolithes, s. str., the margin of the flattened
side projects somewhat above the opposite wall.
The forms known as Cleidotheca, Centrotheca,
Salter ; Camerotheca, Diplotheca, Matthew ; Phare-
trella, Hall ; Ceratotheca and Bactrotheca, Novak,
fall within the synonomy of Hyolithes. This
genus is abundantly distributed in the Cambrian,
Ordovician, and Silurian of North America, Great
Britain, Sweden, Russia,

and Bohemia ; it occurs (Etage' D)7 Lodenicer'BohemiaT Slightly'
ermrinrrlv ilan in tnP TV reduced. C, II. HKi.rinuix, Ha IT. Cambrian
Sparingly alSO in tlie L>e- (6tage C); 'MleschitZ) Bohemia. Anterior

VOnian, Carboniferous, and portion restored, with operculum ; viewed

-P. . from the side, 1/9. D, Operculum (after

Permian. Barrande).

Pterotheca, Salter;

Phragmotheca, Barrande. Silurian. Matthewia, "Walcott.
Cambrian.

Family 4. Conulariidae. Walcott.

Shell rectilinear, inversely conical, rect-
angular to rhombic in cross -section, "•///,
usually sharp edges, acute or truncated pos-
teriorly. Each of the transversely striated or
ribbed lateral faces divided into longitudinal
halves by a superficial groove, corresponding
internally to a median ridge. Posterior
portion of the shell divided off by septa.
Aperture constricted by four triangular or
linguiform incurved lobes of the anterior
margin. Ordovician to Jura.

I 'I... 1026.

Conularia quail i-ixul-
cata, Sowb. Upper
Carboniferous I. me-

FIG. 1025.

Conularia anomala, Barr.
Ordovician (EtageD);
Drabov, Bohemia.

Gonularia, Mill. (Figs. 1025, 1026).
: This, the solitary genus, sometimes attains

i a length of 20 cm., and is represented bv
&rgine (after Ethe- , ' . J ,. .,

ridge). about 100 species. Its maximum distribu-

tion occurs in the Ordovician and Silurian

of Bohemia, Normandy, England, Sweden, and North America, and in the Devonian
of North America and Bolivia. It is rare in the Carboniferous and Permian, and
the last surviving species occurs in the Trias and Lias.

492

MOLLUSCA

SUB-KINGDOM VI

Order 2. PULMONATA. Cuvier. Air-breathing Snails.1

Euthyneura in which the gill cavity is transformed into a lung for breathing free air.
Mainly terrestrial or fresh-water forms.

A few Pulmonates have reverted to exclusively aquatic habits, and have the lung
filled with water ; and in a few, secondary gills are developed in the cavity. These,
however, are rare exceptions. The great majority of forms breathe air by means of a
network of blood-vessels spread upon the inner surface of the lung. The ordinary
aquatic forms come to the surface of the water at intervals to renew their supply of
air. They have, with few exceptions, no operculum, and the shell is often vestigeal or
absent.

Next to the Prosobranchs the Pulmonates are the largest group of Gastropods,
there being upwards of 6000 living and 700 fossil species known. The most
important and highly diversified genera (Helix, Bulimus, Clausilia} are terrestrial in
habit ; certain others (PlanorMs, Limnaea, Physa) are confined to fresh water. The
oldest Pulmonates are of rare occurrence in the Devonian and Carboniferous ; they
are found sparingly in the Jura and Cretaceous, are of greater abundance in the
Tertiary, but do not attain their maximum distribution until the present geological
period.

The Thalassophila and Auriculidae are restricted to marine deposits ; remaining
Pulmonates are rarely found outside of fresh-water strata, and are commonly associated
with other fresh- water organisms that have been swept by rainfall or running water
into swamps or estuaries.

Sub-Order A. THALASSOPHILA. Gray.

Shell either spiral and operculate, or bowl-shaped to depressed conical, without spire,
and somewhat unsymmetrical. Animal usually provided with a single gill in addition
to the lung cavity. Tentacles fused with the discoidal head. Eyes sessile.

The Thalassophila inhabit the littoral zone of the ocean and brackish estuaries. Fossil
remains occur from the Devonian onward. Three families are recognised — Siphonari-

idae, Gadiniidae, and Am-
phibolidae ; but these are
not readily distinguishable
by shell characters alone.

Siphonaria, Blainville
(Fig. 1027). Shell usually
radially ribbed. Apex
directed backwards or to-
ward the left side; internally
with two unequal muscular
impressions, which are in-
De- terrupted on the right side
in front by a broad groove.
Tertiary and Recent.
Anisomyon, Meek and Hayden. Jura

FIG. 1027.

Siphonaria crassicostata, Desh.
Eocene ; Anvers, near Paris.

FIG. 1028.

Hercfinclln bohemica, Barr.
vonian (Etage F) ; Lochkow,
Bohemia.

Devonian.

Hercynella, Kayser (Fig. 1028).
and Cretaceous.

Valenciennesia, Rousseau. Shell very thin, broadly bowl-shaped, concentrically
ribbed. Apex situated near the posterior margin. Right side bearing a broad

1 Sandberger, F., Land- itnd Siisswasser-Conchylien der Vorvvelt. 1870-75.
]\'/>ite, C. A., Review of American non-marine Mollusca.
Tryon, G. W. and Pilsbry, H. A., Manual of Conchology, Pulmonata.

SUB-OKI >KK I!

BASOMMATOPHORA

p..:',

plication for the respiratory tube. Fouinl in brackish water, Congfri.m
of Hungary, Roumania, and South Russia.

ll'illiamia, Monts. ; Gadinia, Gray. Recent and Pliocene.

Amphibola, Schuni. Shell spirally globose, thick, rugose, and eip.-mil.-itr.
This is placed in a separate family, Amphibolidae.

!{••< •«-ni.-

Sub-Order B. BASOMMATOPHORA. A. Schmidt.

Shell invariably present. Eyes situated at the base of a pair of tentacles. A<jn<it«\
or living in the vicinity of water.

FIG. 1029.

Auricula Dutem
plei, Desh. Lower
Eocene ; Sainceux
(after Deshayes).

Pythiopsis La-
Alexiapisoli?ia, Desh. marcki, Desh. sp.
Miocene ; Pontlevoy, Eocene ; Houdan
Touraine. 2/j. (after Deshayes).

FIG. 1032.

Carychium ant !<j H n m .
A. Braun. Mioct-nc :
Hochheim, near
Mayence. Enlarged.

Family 1. Auriculidae. Blainvilh-.

Shell thick, ovate. Spire short, body whorl very large. Inner lip or columella bear-
ing plications. Shore forms or inhabitants of salt marshes. Jura to Recent.

Auricula, Lam. (Fig. 1029). Elongate-oval, with epidermis. Aperture narrow.
rounded an-
teriorly. Inner
lip bearing two
or three folds ;
outer lip thick-
ened, some-
times denticu-
lated. Jura to FlG 1029 PlG< 1031
Recent. *..~*~.»- n,.«.,,, FIG. ioso.

Cassidula,
Fer. ; Pleco-
trema, Adams ;
Alexia, Leach (Fig. 1030); Pythiopsis, Sandb. (Fig. 1031); Melampus, Montf.

Carychium, Mull. (Fig. 1032). Shell small, smooth, and glossy. Inner lip
bearing one or two folds; outer margin thickened, sometimes with
a tooth. Jura to Recent.

Scarabus, Montf. (Polyodonta, Fischer and Waldh.) ; Leuconia,
Gray ; Blauneria, Shuttleworth, etc. Tertiary and Recent.

Family 2. Chilinidae. Dall.

Shell oval, auriculate, with large aperture, the columellar margin
provided with spiral folds; surface coloured in various patterns.
Tertiary and Recent.

Chilina, Gray. This is said to be Streptoneurous. The denti-
tion resembles that of Physa. Miocene and Recent ; South
America.

K;'n lily 3. Physidae. Dall.

FIG. 1033.

Physa gigantea,
Micliaud. Lower
Eocene; Hilly, near
Rheime.

Shell sinistral, oval, glossy, unicoloured. Aperture large ;
columella twisted or simple. Jura to Recent.

Physa, Drap. (Fig. 1033). Shell resembling Limnaea, but
sinistral. Upper Jura to Recent.

Family 4. Limnaeidae. Keferstein.

Shell thin, turreted, or discoidal. Fresh-water inhabitants. Lias to Recent ; especi-
ally abundant in the Tertiary.

494

MOLLUSCA

SUB-KINGDOM VI

Limnaea, Lam. (Limnaeus, auct.), (Fig. 1034). Shell so thin as to be translucent.
Body whorl very large ; spire acute, and moderately high. Aperture wide, oval ; outer

margin sharp. Upper Jura
(Purbeck) to Eecent ; maximum
in Tertiary.

Planorbis,
1035, 1036).
tionally
whorls.

Fio. 1034.

Limnaeus pachygaster,
Thoin. Fresh - water
Miocene ; Morsingen,
near Ulin.

Guettard (Figs.
Discoidal (excep-
turreted), with many
Aperture oval to
crescent -shaped ; outer margin
sharp. Lias to Recent; very
profuse in the Tertiary. P.
multiformis, Bronn sp., from the
Middle Miocene of Steinheim in
Wurtemberg, is particularly in-
teresting 011 account of its extraordinary variability. The different mutations of the
species are usually found at different horizons of the fresh-water limestone occurring

FIG. 1035.

Planorbis cornu, Brongt. var.
telli, Bunker. Upper Miocene ;
dingen, Wurtemberg.

Man-

Mun-

FIG. 1036.

Planorbis multiformis, Bronn sp. Upper Miocene fresh -\vater limestone; Steinheim, near Heidenheim,
Wiirtemberg. A, var. supremn. B, var. trochiformis. C, var. elegans. D. var. steinheimensis.

there, and constitute, according to Hilgendorf and Hyatt, a remarkable genealogical
sequence.

Isidora, Ehr. Shell similar to that of Phijsa. Recent ; tropical countries.

Family 5. Ancylidae.

Shell limpet-shaped, conical, not spiral, or with the apex recurved. Tertiary and
Recent.

Ancylus, Geoffrey (Fig. 1037). Shell simply conic or with the apex slightly
incurved. Tertiary and Recent.

Gundlachia, Pfeiff. An accessory shell at the apex of the prin-
cipal one. Tertiary of Mayence Basin and Recent.

Sub-Order C. TELETREMATA. Pilsbry.

Shell absent ; mantle covering the whole upper surface of the body. FIQ 1Q3.,
Male and female orifices widely separated; lung orifice and anus Ancylus Dutemplei,
ventral and near the tail. Desh. Caicaire

Grossier; Boursaiut.

Several families of this sub -order are recognised (Vaginulidae,
Rathouisiidae, Onchidiidae), but owing to the absence of a shell, their remains are not
preservable in the fossil state.

Sub-Order D. STYLOMMATOPHORA A. Schmidt. Land Snails.

borne on the extremities of two peduncles, which are capable of invagination ;
a pair of short tentacles, rarely obsolete, are placed in front of them. Male and female
genital orifices contiguous, or uniting in a common vestibule, situated at the right or

S.K-ORDER D STVLOMMATOPHORA 495

left side of the head. Buccal retractors present ; lung foramen ami </////.< mitf.n'ur t<> end
of foot, not ventral.

This sub-order comprises most recent and all fossil land snails, and i.- di\ i-il.lc
into series or siiperfainily ^i-oups. The families proper are baaed almost wholly upon*
characters of the soft anatomy, \\hirli arc hrivin lar^-ly nmitt«-d or abridged.

Superfamily 1. HOLOPODA. Pilsbry.

No longitudinal grooves above the margins of the foot ; jaw present, teeth quadrate.

Family 1. Helicidae. Keferstein. Helices.
Shell depressed, globose, or oval and elevated. Tertiary and Recent.

This comprises an enormous assemblage in the recent fauna, but most of the genera
have not as yet been found fossil. All the typical forms will probably in time be
traced back to the Eocene. Sub-family and generic characters are based largely upon
the genital system, and hence are of
little practical importance to the
palaeontologist.

Polygyra, Say. Globose or de-
pressed, with the lip reflected, often
toothed. Miocene to Recent ; North
America.

' Sagda, Beck Glossy, with many Dimorpjwptychia Ar)"dd i( Michaud. Lower Eocene ;

close Whorls, the last usually With Rilly, near Rheims. B, Helix (Campylaea) inflew, Klein.

in+aT-rml Inminnp anrl a sliarri lir. uPPer Miocene ; Morsingen. C, Helicodonta

i Sliarp lip. Thom Lower Miocene . Hochheim, near Wiesbaden.

Oligocene to Recent ; Antilles.

Pleurodonte, Fisch. de Wald. Solid, large, depressed, and generally keeled ; aperture
often toothed. Oligocene to Recent ; Antilles, Florida.

Helix, Linn. (Fig. 1038, A, B). Shell semi-globose, conical to discoidal, manifesting
great variability of form. Aperture oblique, crescentic or rounded, with disconnected
margins. Very profuse in the Tertiary and Recent of Europe and adjacent regions of
Asia and Africa.

Helicodonta, Fer. (Fig. 1038, (7). Similar to Helix, but with thickened or
denticulated lip. Oligocene to Recent ; Europe.

Other allied genera occur in European Tertiary deposits. Recent
Helicidae reproducing by extraordinarily large eggs are the following : —
Helicophanta of Madagascar ; Acavus, Ceylon ; Panda,
Australia ; Strophocheilus, South America.

Family 2. Bulimulidae. Fischer.

Shell elongated, ovate, with narrow umbilicus or none.
Tertiary and Recent.

Bulimulus, Leach. Miocene to Recent ; America. Am-
phidromus, Alb. Tertiary ; Europe and Asia.

FKJ. 1039.

A, ClausiUa H«H«oW«, A. Family 3" **&***•

Braun. Lower Miocene;
Eckingen, near uim. B, c. Shell small, cylindrical or oval, with narrow whorls.

iocaiiir Schiibler- Same Tertiary and Recent.

Clausilia, Drap. (Fig. 1039). Shell turreted to fusiform,
slender, sinistraL Aperture pyriform, with usually continuous peristoine. Inner lip

496

MOLLUSCA

SUB-KINGDOM VI

bearing two folds ; outer margin somewhat reflected ; the aperture usually closed
A B by a movable calcareous plate. Occurs

sparingly fossil from the Eocene onward, and
represented by about 400 recent species.

Pupa, Lam. (Fig. 1040, B). Shell
small, cylindrical -ovate. Aperture semi-
circular, usually constricted by teeth on
the columella and inner and outer lips.
The outer margin reflected. Tertiary and
Kecent.

Dendropupa, Dawson (Fig. 1040, A)

FIG. 1040.

A, Dendropupa vetusta,
Dawson. Coal Measures ;
Nova Scotia (after Dawson).
£, Pupa diversidens, Sandb.
Miocene ; Sansan, Gers (after
Sandberger).

FIG. 104].

Like the last, but aperture without teeth.
Miocene; Carboniferous; Nova Scotia.

Lo wf

Thalflngen, near Ulm.

Vertigo, Miiller.

Buliminus, Ehrb. (Fig. 1041). High conic, solid, turreted.

Tertiary and Eecent.
Eocene to Eecent.

Family 4. Achatinidae.

Ovate or elongate, imperforate shells, with the columella generally truncated at the
base. Upper Cretaceous to Recent.

Achatina, Lam. Recent ; tropical Africa.

Stenogyra, Shuttlew. ; Rumina, Risso ; Opeas, Alb. ; Rhodea,
Adams. These are all small members of the group, mainly Recent.

Megaspira, Lea (Fig. 1042). Turreted, slender, very long ;
columella with transverse folds. Upper Cretaceous to Recent.

Cionella, Jeffreys ; Azeca, Leach ; Caecilianella, Bourg., etc.
Tertiary and Recent.

Superfamily 2. AGNATHA. Morch.

Meijaspira exarata,

Carnivorous snails, usually with no jaw, thorn-shaped teeth, and Eocene ;SIRiiiy, °near

without furrows above the foot-edges.

Rheims

FKI. 1043.

Testacella Zellii, Klein.
Miocene ; Andelfingen
(after Sandberger).

Family 1. Testacellidae. Gray.

Shell spiral, of very small size, and situated near the tail of the
vermiform animal. Tertiary and Recent.

Testacella, Cuv. (Fig. 1043). Shell auriform,
borne on the posterior end of the animal.
Tertiary and Recent.

Parmacellina, Sandb. Eocene. Daude-
bardia, Hartm. (Helicophanta, Fer. p.p.).
Quaternary and Recent.

Family 2. Grlaiidinidae.

Shell oval or oblong, capable of containing the entire animal.
Cretaceous to Recent.

Glandina, Schum. (Fig. 1044). Shell elongate- oval, with high
spire. Aperture notched in front ; columella truncated. Upper
Cretaceous to Recent. Other recent allied genera inhabit the
American tropics. elberg, near Ulm.

FIG. 1044.

SUB-ORDER D

STY LO.MM. \TOPHORA

Superfamily 3. AULACOPODA. Pilsbry.

l<'<K>t with longitudinal grooves above and parallel with its lateral margins.

Familv 1. Zonitidae.

Aulacopoda with a spiral, conic, or helicoid shell, sometimes partially uncoiled,
usually smooth and with simple lip ; marginal teeth of the radula thorn-like ; foot
iintnihi wide; JOAV rather smooth. Carboniferous (?) to Recent.

I'/'trina, Drap. Shell small, translucent, with short spire, and very large body
\vhorl. Tertiary and Recent.

Archaeozonites, Saiulb. (Fig. 1045). Thick-shelled, globose, with rather high spire,
deeply umbilicate ; outer nun-gin sharp. Oligocene and Miocene. Here also should

Ki<;. 1045.

Archaeozonites subverticillus,
Saudi). Lower Miocene;
Eckingen, near Ulm.

FIG. 1046.

Hyalina denudatn,
Reu'ss sp. Miocene ;
Tuchoritz, Bohemia.

Fir,. 1047.

Lychnus Matheroni, Requien.
Upper Cretaceous (Garunmiai,) ;
Rognac, Provence.

be placed, perhaps, the archaic Helix-sliaped snails from the Coal Measures of Nova
Scotia.

Zonites, Montf. Like the last, but with thinner shell, granulated above, and
smooth below. Tertiary and Recent.

Hyalina, Fer. (Fig. 1046) ; Omphalosagda, Sandb. ; Ariophanta, Desm. ; Trocho-
morpha, Albers. Tertiary and Recent.

Lychnus, Montf. (Fig. 1047). Body whorl large, bent upward at first, and later
decurved, so that the margins of the aperture lie in the basal plane. Upper Cre-
taceous of Provence and Spain.

Family 2. Limacidae. Lamarck.

Naked slugs having a small vestigeal shell, flat and non-spiral, concealed within the
mantle, which latter forms a small oval shield on the forepart of the body. Foot margin
narrow ; dentition and jaw as in the Zonitidae. Tertiary and Recent.

The principal genera are Lima.c, Linn., in which the intestine has four longi-
tudinal folds, and the back is keeled at the tail only ; and Amalia, Moq.-Tand., with
spiral gut and strongly keeled back. Their small scale-like shells have been found
in the Tertiary and Pleistocene ; present distribution nearly world-wide.

Family 3. Bndodontidae. Pilsbry.

Shell spiral and external, varying from cylindric to helicoid and planorboid, usually
rib- sculptured and with opaque colouring; lip thin, unexpanded. Jaw of separate or
united imbricating plates, or solid and striated; marginal teeth squarish; genitalia
without accessory organs. Carboniferous to Recent.

VOL. I 2 K

498 MOLLUSCA

SUB-KINGDOM VI

Punctinae. Jaw of numerous separate plates ; shell minute. Includes the
Holarctic genera Punctum, Morse, and Sphyradium, Charp., and the New Zealand
genus Laoma, Gray. Recent.

Endodontinae. Jaw-plates united more or less completely. Genera : Pyramidula,
Fitz. Discoidal or low conic, with tubular ribbed whorls and open umbilicus. Car-
boniferous to Recent. This is one of the most ancient land Mollusks known, and is
the oldest Helicoid form. Phasis, Amphidoxa, Flammulina, and Endodonta, Alb., are
similar austral forms, but are only known Recent,

Family 4. Arionidae.

Slugs having the shell reduced to a flat plate or a few granules, nearly or entirely
concealed, or absent. Mantle in the form of a shield on anterior part of the body ; teeth
of the quadrate type. Recent.

This family is probably derived from the Endodontidae by degeneration of the
shell. Arion, Fer., and Anadenus, Heyn., are leading genera of Europe and Asia ;
Ariolimax, Morch., and Prophysaon, Bland, those of North America.

Family 5. Philomycidae.

Slugs somewhat similar to Arionidae, but the mantle covers the entire upper surface
of the body. A shell is completely absent ; hence no fossil forms are known.

Superfamily 4. ELASMOGNATHA. MSrch.

,A Jaw with a strong squarish process of attachment above.

\j^ Family 1. Succineidae.

FIG. 1048. Shell thin, ovate, consisting of few whorls.

SanS^Low^S: Succinea, Pfeiffer (Fig. 1048). Shell thin, ovate, amber-coloured,
cene ; Tuchoritz, translucent, with short spire, and large body whorl. Outer margin
of aperture sharp. Tertiary and Recent ; abundant in the Loess.

Range and Distribution of the Gastropoda.

Of all classes of Mollusks, the Gastropods exhibit the most manifold
variety. Beginning in the Cambrian, they acquire a very gradual increase
and distribution, and are at present enjoying their maximum vigour. There
exist probably over 20,000 recent species, about three-fifths of which have
gills, the remainder being air-breathers.

At the base of the Cambrian (Olenellus zone) are found such archaic
genera as Scenella, Stenotheca, Platyceras, Rhaphistoma, Pleurotomaria, and a
number of doubtful Pteropod-like forms (Hyolithes, Hijolithellus, Salterella, Torel-
lella, etc.), which evince the great antiquity of the Aspidobranchs and forms
resembling the Capulidae. In the later Cambrian the Ehipidoglossa (represented
by the Pleurotomariidae, Euomphalidae, and Bdlerophontidae) predominate ; and
associated with these are certain Pteropod remains, members of the Capulidae,
and a few genera probably referable to the Turbinidae. A notable genus
occurring here is Subulites, which bears some resemblance to the Pyramidellidae,
and exhibits a distinct channelling at the base of the columella."

Unfortunately the poorly preserved remains of Cambrian Gastropods afford

SUB-ORDER D RANGE AND DISTRIBUTION OF Till: (JASTROPODA 499

but scanty information regarding the disposition of the soft parts ; neverthe-
less, there are good, although purely theoretical reasons for supposing that
the Rhipidoglossa and Ctenobranchs were formerly not so widely separated as
at present.

During the Ordovician and Silurian, Gastropods increased perceptibly in
the number of species, and a few new families were initiated (S!ea/« /•/'/'/ A//-,
Purpurinidae, Trochidae, Xenophoridae) • but the faunal aspect remained on
the whole much the same as in the Cambrian, and no essential changes were
introduced during the remainder of the Palaeozoic. Accordingly, the Palaeo-
zoic Gastropod fauna may be said to be characterised by its general simplicity,
being made up principally of so - called Pteropods, Rhipidoglossa, a few
Docoglossa and Opisthobranchs, and also a scattering representation of Cteno-
branchs (Capululae, Pt/ramidellidae, Littorinidae).

During the Jura-Trias, the large, thick-shelled varieties of Pteropod-like
Mollusks became extinct. But, on the other hand, various families of the
Rhipidoglossa reached the acme of their development (Pleurotomariidac, '/'///•-
linidae, Neritopsidae, Neritidae) ; and among the Ctenobranchs, the families
Pyramidellidae, Nerineidae, Purpurinidae, Turritellidae, and Aporrhaidae multi-
plied in a great variety of forms.

The Cretaceous witnessed a decided increase among the siphonostomous
Ctenobranchs, and in the Tertiary this branch asserted itself as the dominant
type of Gastropods, surpassing all other families in point of numbers, and
gradually acquiring the aspect of living genera and species. The Nerineidae,
Pyramidellidae, and Aporrhaidae, which played such a prominent role along
with the Rhipidoglossa during the Mesozoic era, became in part extinct in the
Tertiary, and the remainder entered upon their decline. The great majority
of Eocene and Oligocene genera are still living, but the species have almost
without exception become extinct. During the Miocene, a few species made
their appearance which are still in existence, and of the Pliocene species,
between 80 and 90 per cent are represented in the recent fauna.

The geological history of the Pulmonafa is remarkable. Thalassophilous
Siphonariidae are first met with in the Devonian, where they are very sparse.
Land snails (Archaeozonites, Pyramidula, Dendropupa} were initiated in still
smaller numbers during the Carboniferous ; but not until the boundary between
the Jura and Cretaceous is reached do we find any traces of fresh- water snails.
We meet them first in the Purbeck. In the "Wealden, and Cretaceous gener-
ally, both land and fresh-water Gastropods are quite abundant ; they became
highly developed and widely distributed during the Tertiary, attaining, in fact,
a differentiation nearly equal to that exhibited by the corresponding recent
forms.

The successive approximations to present conditions among Gastropod
faunas have not been confined to the production of forms simulating more and
more those now living ; they include also the gradual demarcation of existing
geographical provinces. Mesozoic Gastropods are too dissimilar in their
general characters to admit of a close comparison with modern faunas ; but as
early as the Eocene resemblances to modern forms are observable, and a certain
correspondence is to be noted with Gastropods now inhabiting somewhat
warmer zones.

The Eocene faunas of Europe, North America, Asia, and Northern Africa
share a great many species in common, and have numerous others which are

500

MOLLUSCA

SUB-KINGDOM VI

TABLE SHOWING THE VERTICAL RANGE OF THE GASTROPODA.

Families.

Cambrian.

Ordovician.

0}

Devonian.

Carboniferous. 1

Permian.

H

2
i^

Crctaci'ous.

|
1

«!

1

1. Streptoneura
ORDER 1. ASPIDOBRANCHJA
A. Docoglossa .

B. Rhipidoglossa,
1 Haliotidae

2. Pleurotomariidae .
3. Bellerophontidae .
4. Fissurellidae .
5. Euomphalidae
6. Stomatiidae .
7. Turbinidae
8 Phasianellidae

•

?

— — ^

9 Delpliinulidae

10. Trochonematidae .
11. Trochidae

^— —

— ^—

14 Neritidae

ORDER 2. CTENOBRANCHIA

A. Heteropoda .
B. Platypoda
1. Eulimidae
2 Pyramidellidae

..._

3. Scalariidae
4 Solariidae

5. Purpurinidae .
6. Littorinidae .
7 Cyclostomidae

8 Capulidae

9 Naticidae

10. Xenophoridae
11 Ampullariidae

«-»

12 Valvatidae

13 Vivipavidae . .

14 Amnicolidae .

15 Rissoidae

16. Turritellidae .
17. Vermetidae .
18 Caecidae

!^—

^— —

19. Melaniidae

20 Nerineidae

21 Cerithiidae

22. Aporrhaidae .
23 Strombidae

24. Columbellinidae

RANGE AND DISTRIBUTION OF THE GASTROPODA

501

Families.

Caiiiliiiaii.

0

Silurian.

MMMIIOA..,!

1

\ ' ,:

2

— .

2

j

25. Cypraeidae
26. Ovulidae
27. Cassididae
28. Doliidae
29. Tritonidae
30. Columbellidae
31. Buccinidae
32. Muricidae
33. Purpuridae
34. Fusidae .
35. Turbinellidae .
36. Volutidae
37. Harpidae
38. Olividae.
39. Cancellariidae
40. Pleurotomidae
41. Conidae .

2. Euthyneura
ORDER 1. OPISTHOBRANCHIA
A . Tectibranchiata
1. Actaeonidae .
2. Ringiculidae .
3. Akeratidae
4. Hydatinidae .
5. Bullidae
6. Tornatinidae .
7. Scaphandridae
8. Philinidae
9. Umbraculidae .
B. Pteropoda
1. Limacinidae .
2. Cavoliniidae .
C. Conularida
1. Tentacnlitidae
2. Torellellidae .
3. Hyolithidae .
4. Conulariidae .

ORDER 2. PULMOXATA
A. Thalassophila
B. Basommatophora
1. Auriculidae .
2. Chilinidae
3. Physidae
4. Limnaeidae .
5. Ancylidae

C. Tcletremata
D, Stylommatophora

_—

—

—

— »

E

^^~

______

—^^^

— — .

—

— —

— ^~

—

—

~~~

______

— —

—

—

—

—

—

—

502 MOLLUSCA SUB-KINGDOM vi

vicarious. A very different aspect is presented by the Eocene fauna of
Australia, New Zealand, and South America, where we find the evident fore-
runners of forms now inhabiting the southern portions of the Atlantic and
Pacific Oceans.

Still more intimate is the relationship existing between the fossil land and
fresh-water Gastropods and their descendants on the several continents. It
has been observed that Miocene faunas bear a decidedly tropical stamp. On
this account European and American forms from the inland Miocene deposits
bear some resemblance to the recent faunas of the Azores and the West
Indies, as well as to the land and fresh- water Gastropods inhabiting the colder
latitudes of Europe and Asia. Only as recently as the Pliocene did each
geographical province come to assume its present distinctive features.

In general, the stratigraphic sequence of Gastropod groups corresponds
closely with the zoological order, the most generalised forms appearing first,
the more specialised later. Beginning with the two-gilled PMpidoglossa and
the Docoglossa, followed by the single-gilled Pihipidoglossa, Opisthobranchs, and
taenioglossate Ctenobranchs, the series leads to Racliiglossa in the later Mesozoic,
and culminates in the great increase of rachiglossate and toxoglossate families
in Tertiary and Recent times.1 (See tables, pp. 500, 501.)

^ CEPHALOPODA.2

Head sharply defined in recent forms, except Nautilus. Foot transformed into a

[l Grateful acknowledgments are due to Professor Henry A. Pilsbry, of the Philadelphia Academy
of Natural Sciences, for his revision of the preceding Gastropod chapter. The difficulty of
adapting a strictly zoological classification, based largely upon the anatomy of the soft parts, to the
practical needs of the palaeontologist, is strikingly illustrated by the class of Gastropods. A
revolutionary, or even extreme course has been avoided ; and it is hoped that the system herein
adopted will be found to possess some practical advantages. — TRANS.]

2 Literature :

Angdin, JV. P., Fragmenta Silurica, edited by G. Lindstrom. Stockholm, 1880. — Arthaber,
G. von, Die Cephalopodenfauna der Reiflinger Kalke (Beitr. Palaeont. Geol. Oesterreich-Ungarns
und Orients, Mojs. und Neumayr, Bd. X. Hefte I.-IV.), 1896.— Barrande, J., Systeme Silurien de la
Boheme, vol. II. Cephalopodes. 1867-77. — Bayle, JE., and Zeiller, R., Explication de la Carte geolo-
gique de la France, vol. IV., Atlas. Paris, 1878. — Beecher, G. E., On the Development of the Shell
in Tornoceras (Amer. Journ. Sci. [3], vol. XL. p. 71), 1890. — Beyrich, II. E., De Goniatitis in monti-
bus rhenanis occurrentibus. Inaug. Dissert. Berlin, 1837. — Billings, E., Palaeozoic Fossils. Geol.
Surv. Canada, 1865—Blainville, H. M. de, Memoire sur les Belemnites. Paris, 1827.— Blake,
J. F., Monograph of the British Fossil Cephalopoda, Part I. London, 1882. — Bonarelli, G., Osser-
vazioni sul Toarciano d' Aleniano (Boll. Soc. Geol. Italiana, vol. XII. p. 195), 1893. — Branca, W.,
Beitrage zur Entwickelungsgeschichte der fossilen Cephalopoden (Palaeontogr., Bd. XXVI., XXVII.),
1880-81.— Brown, A. P., On the Young of Baculites compressus (Proc. Acad. Nat. Sci. Philad.,
1891, p. 159), 1892.— Buck, L. von, Ueber Goniatiten, Clymeuien, Ceratiten, etc. (Abhandl. Berlin.
Akad., 1830, p. 159 ; 1838, p. 149 ; 1848, p. \).—Buckman, S. S., Monograph of the Inferior Oolite
Ammonites (Palaeont. Soc.), 1887-96.

Canavari, M., Sui fossili del Lias inferiore nell' Appenino ceutrale (Atti Soc. Toscano, vol. IV.
p. 141), 1879. — La fauna degli strati con Aspidoceras acanthicum di Monte Serra (Palaeont. Italica,
voL II. p. 25), 1897.— Clarke, J. M., The Protoconch of Orthoceras (Amer. Geol., vol. XII. p. 112),
1893. — Nanno, a new Cephalopodan type (ibid. XIV. p. 205), 1894. — The Lower Silurian Cephalo-
poda of Minnesota (Geol. Minn., vol. III. Part II., Palaeont, p. 760), 1897.— Conrad, T. A., Obser-
vations on the Silurian r.nd Devonian Systems, etc. (Journ. Acad. Nat. Sci. Philad., vol. VIII.
p. 228), 1839 - 42. — Observations on Recent and Fossil Shells (Amer. Journ. Conch., vol. II.
p. 104), 1866. — Deslong champs, E., Memoire sur les Teudopsides (Mem. Soc. Linn. Normandie,
vol. V. p. 68), 1835. — Diener, C., Triadische Cephalopodenfaunen der ostsibirischen Kiistenprovinz
(Mem. Com. Geol. St. Petersb., vol. XIV. No. 3), 1895.— Douville, H., Sur quelques fossiles de la
zone a Ammonites Sowerbyi (Bull. Soc. Geol. France [3], vol. XIII. p. 12), 1884-85. — Sur la classi-

(LASS v CEPHALOPODA 503

funnel-shaped muscular swimming -organ ; mouth provided with jaws and radnl».

fication des Ceratites do la (.'rait- (ibid. XVIII. p. L'7/i), 1890.— /;//•/>////. IT. /;.. i:«-.,.|it Explorations
in the \Vappin-er Valley Limestone (Amer. .Jmirn. S.-i. [:!|, ToL XXVII. p. L'19), 1884.

Foiit-d, A. H., Catalogue of the Fossil Cephalopoda in the British Mu-.-um, Part I., 1888 ;
II., 1891 ; III. (Foord and Crick), 1897.— /-Y" •//. /'., Lethaea Geognostica, I. Theil. Lethaea Palaeo-
zoica, Bd. II. Lief. 1. Stuttgart, 1897.— /•'//»•////, .1.. La fauna d«-l Lias medio del Monte C'alvi
(Palaeont. Italica, vol. II. p. 203), 1897.— Gabb, IT. M.. and M,;k. /'. II., <;••«,]. Surv. ( 'alitnrnia.
Palaeontology, vols. I., II., 1864-69. — dV/// ////•//"/•», <;. (,'., La fauna dei ealcari con Fusulina.
Palermo, 1887-89.— G'/v//, ./. .!.. List of tin- Criu-ra of Recent Mollusca (Proc. Zool. Soc. London,
vol. XV. p. 129), 1847. — Griesbach, C. L., Palaeontological Notes on tlie Lower Trias of the
Himalayas (Records Geol. Surv. India. v..ls. Mil.. XIV.), 1880-81.— GWv,,//,v,-, A., L-s Ammonites
de la Craie superieure de la France (Explic. Carte Geol. France), 1893.— Gilmbel, C. II'., Ueber di«-
baierischen Alpen ( \\-rhandl. Geol. Reichsanst. Wien, Bd. XII. p. 257), 1861-62.— Revision der
Goniatiteu des Fichtelgebirges (NYm-s ,Iahrl»., p. 284), 1862.— Ueber Clyinenien in den Uebergangs-
gebilden des Fichtelgebirges (Palaeontogr., Bd. XI. p. 85), 1863-64.— //"//. ./., Palaeontology of
New York, vols. I.-III., V. Albany, 1847-79.— Hatter, F. v., Die Cephalopoden des Sal/kannn.-r-
gutes mid des Muselielmarmors. Wien, 1846. — Neue Cephalopoden von Hallstadt unrl A
(Haidiuger's Wissen. Abhandl., Bd. I. p. 257 ; III. p. 1), 1847-50.— Beitrage zur Kenntniss der
Cephalopodenfauna der Hallstadter Schichten (Deukschr. Akad. Wissensch. Wien, Bd. IX. p. 141),
1855. Nachtrage, Sitzuugsber., Bd. XLI. p. 113, I860.— Choristoceras, etc. (ibid. Bd. LII. p. 654),
1866. — Die Cephalopoden • des bosnischen Muschelkalkes (Denkschr. Akad. Wissensch. Wien.
Bd. LIV. p. 1 ; LIX. p. 251) ; 1888-92. — Hang, E., Beitrage zu einer Monographic der Ammoniten-
(Jattung Harpoceras (Neues Jahrb. Beilage, Bd. III. p. 585), 1885.— Ueber die Polymorphidae, etc.
(ihnt. Bd. II. p. 89), 1887. — Holm, G., Ueber die innere Organisation einiger silurischer Cephalo-
poden (Palaeont. Abhandl. Dames und Kayser, Bd. III. p. 1), 1885. — Tvenne Gyroceras-formigt
bojda Endoceras-Arter (Geol. Foren. Stockholm Forhandl., Bd. XIV. Hefte 2, 3), 1892.— Om de
endosifonala bildningarna hos familien Endoceratidae (ibid. XVII. Heft 6), 1895.— Om apikalanden
hos Endoceras (ibid. Bd. XVIII. p. 394 ; XIX. p. 171), 1896-97.— Holzapfd, E., Die Cephalopoden-
fiihrenden Kalke des untereu Carbon (Palaeont. Abhandl. Dames und Kayser. Bd. V. Heft 1), 1889.
— Huxley, T. //./Structure of Belemuites (Memoirs Geol. Surv. United Kingdom, Monogr. II.), 1864.
— Hifutt, A., The Fossil Cephalopods of the Museum of Comparative Zoology (Bull. M. C. Z., vol. I.
p. 71), 1868.— Remarks on Agassiceras and Oxynoticeras (Proc. Boston Soc. Nat. Hist,, vol. XVII.
p. 236), 1875. — The Jurassic and Cretaceous Ammonites collected in South America (ibid. XVII.
p. 365), 1875.— Genera of Fossil Cephalopods (ibid. XXII. p. 253), 1884.— The Genesis of the
Arietidae (Smithson. Miscell. Collect., No. 673, and Memoirs M. C. Z., vol. XVI.), 1889.— Carbon-
iferous Cephalopoda (I., 2nd Ann. Rep. Geol. Surv. Texas, 1890 ; II., 4th Ann. Rep. 1892).— Phylo-
geny of an Acquired Characteristic (Proc. Amer. Philos. Soc., vol. XXXII., No. 143), 1894.— Remarks
on the Genus Nanno (Amer. Geol., vol. XVI. p. 1), 1895.

Karpinsky, A., Ueber die Ammoneen der Artinsk-Stufe, etc. (Mem. Acad. Sci. Imp. St. Petersb.
[7], vol. XXXVII., No. 2), 1889.— Kilian, W., Sur quelques fossiles du Cretace inferieur de la
Provence (Bull. Soc. Geol., France, vol. XIII. p. 663), 1888.— Koninck, L. G. de, Fanne du calcaire
carbonifere de la Belgique, Part II., Cephalopodes (Ann. Mus. Nat. Hist. Bruxelles, vol. V.), 1880.
— Kossmat, F., Untersuchungen iiber die siidindische Kreideformation (Beitr. Oesterreich-Ungarns
und Orients, Mojs. und Neumayr, vol. IX. Hefte 3, 4), 1895. — Lavbe, G. C., and Bruder, G., Am-
moniten der bohmischen Kreide (Palaeontogr., Bd. XXXIII. p. 217), 1887.—Lindstrow, G., Asco-
ceratidae and Lituitidae of the Upper Silurian Formation of Gotland (K. Svensk. Vetensk. Akad.
Handling., Bd. XXIII. Heft 2), 1889. — Mant<'H, <;. A., Observations on some Belemnites, etc.
(Philos. Trans. 1848, p. 171 ; 1850, p. 393). — Marcoit, «/., Geology of North America. Zurich,
1858. — MatMron, P., Recherches paleontologiques dans le midi de la France. Marseille, 1879-81.
— Mayer, C., Liste des Belemnites des terrains jurassiques, etc. (Journ. de Conchyliol. [3], vol. XI.
p. 181), 1863. — Meek, F. B., Report on the Invertebrate Cretaceous and Tertiary Fossils of the
Upper Missouri Country (U. S. Geol. Surv. Territ., vol. IX.), 1876.— Palaeontology (U. S. Geol.
Exploration 40th Parallel Surv., vol. IV. Part L, with notes on Ammonites by A. Hyatt), 1877.
— Meek, F. B., and Hayden, F. V., Palaeontology of the Upper Missouri (Smithsonian Contrib.
Knowl., vol. XIV., No. 172), 1865.— M< >i<y/iini, G., Monographic des fossiles du calcaire rouge
ammonitique (Lias superieur) de Lombardie (Palaeont. Lombarde). Milan, 1867-81. — Miller, S.
A., North American Geology and Palaeontology, 1889. — Appendices 1892-97. — M»jxi*i>i-i,'x. E. r.,
Das Gebirge um Hallstadt. (Abhandl. Geol. Reichsanst. Wien, Bd. VI. p. 83), 1873-75 ; Part II.,
ifiid., 1893. — Die Cephalopoden der mediterranen Triasprovinz (ibid. Bd. X.), 1882. — Ueber einige
arktische Triasmammoniten des nordlichen Sibirien (Mem. Acad. Imp. Sci. St. Petersb. [7], vol.
XXXVI., No. 5), 1888. — Beitrage zur Kenntniss der obertriadischen Cephalopoden - Faunen des
Himalaya (Denkschr. Akad. Wissensch. Wien, Bd. LXIII. p. 575), 1896.—Jffeufer, G. ron, Beitrage
zur Petrefactenkunde, I.-VIII., 1839-46. — Ueber die Clymenieu und Goiiiatiten im Ueberganskalk
des Fichtelgebirges. Bayreuth, 1843.

Neumayr, M., Jurastudien (Jahrb. Geol. Reichsanst. Wien, Bd. XXI. p. 297), 1871. — Die

504 MOLLITSCA SUB-KINGDOM vi

Sexes separate. Sensory organs highly developed. A circle of fleshy arms or ten-

Cephalopoden-Fauna der Oolithe von Balin bei Krakau (Abhandl. Geol. Reichsanst. Wien, Bd. V.
p. 19), 1871-73. — Die Fauna der Schichten mit Aspidoceras acanthicum, etc. (Verhandl. Geol.
Reichsaust. Wien, p. 29), 1874. — Ueber Kreideammoniten (Sitzungsber. Akad. Wissensch. Wien,
Bd. LXXI. p. 639), 1875 ; also in Zeitschr. deutsch. geol. Gesellsch., Bd. XXVII. p. 854, 1875.—
Ueber unvermittelt auftretende Cephalopodentypen im Jura Mittel-Europa's (Jahrb. Geol. Reichs-
anst. Wien, Bd. XXVIII. p. 37), 1878. — Zur Kenntniss der FaTina des untersten Lias in den
Nordalpen (Abhandl. Geol. Reichsanst. Wien, Bd. VII. Heft 5), 1874-82. — Neumayr, J/., and
Uhlig, V., Ueber Ammonitiden aus den Hilsbildungen Norddeutschlands (Palaeontogr., Bd. XXVII.
p. 129), 1881. — Nickles, R., Contributions a la paleontologie du Sud-Est de 1'Espagne (Mem. Soc.
Geol. France, No. 4, 1890), 1894.—Mkitin, S. N., Der Jura der Umgegend von Elatnia (Nouv.
Mem. Soc. Imp. Moscou, vol. XIV. p. 83 ; XV. p. 41), 1879-89.— Allgemeine geologische Karte von
Russland, Blatt 56 (Mem. Com. Geol. St. Petersb., vol. I., No. 2), 1884.— Die Cephalopodenfauna
der Jurabilduugen des Gouvernements Kostroma (Verhandl. Russ. Mineral. Gesellsch. [2], vol. XX.
p. 13), 1885. — Noetling, F., Cambrische und silurische Geschiebe Ost- und West-Preusseus (Jahrb.
preuss. geol. Landesanst. und Bergsakad.), 1882. — Beitrag zur Kenntniss der Cephalopoden des
Provinz Ost-Preussens (ibid. 1883 ; also Zeitschr. deutsch. geol. Gesellsch., Bd. XXXIV. p. 156),
1882.— Fauna of Neocomian Belemnite Beds (Palaeont. Indica, Ser. XVI., I., Parts 2, 3), 1897.—
Oppel, A., Palaeontologische Mittheilungen aus dem Museum des baierischeu Staates. Stuttgart,
1860-65. — d'Orbigny, A., Paleontologie Francaise, Terrain Cretace. I. Cephalopodes, 1840 ; Terrain
Jurassique, Cephalopodes, 1852. — Prodrome de Paleontologie Stratigraphique. Paris, 1850-53. —
Parana, C. F., Nuove osservazioni sopra la fauna con Posodonomya alpina, etc. (Palaeontogr. Italica,
vol. I. p. 1), 1896.— Fossili albiani d'Escragnolles, del Nizzardo, etc. (ibid. ii. p. 53), 1897.—
Phillips, J., Illustrations of the Geology of Yorkshire, Part II. London, 1836. — Figures and De-
scriptions of the Palaeozoic Fossils of Cornwall, Devon, etc. London, 1841.— Pictet, F. J., Traite
de Paleontologie. Paris, 1853-57. — Pictet, F. J., and Campiche, G., Description des fossiles du
terrain cretace des environs de St. Croix. Geneva, 1858-72. — Pompeckj, J. F., Beitrage zu einer
Revision der Ammoniten des schwabischen Jura, Lief. L, II. Stuttgart, 1893-96. — Ueber Am-
monoideen mit "anorrnaler" Wohnkammer (Jahreshefte Vaterl. Naturk. Wiirttemb., p. 220), 1894.
—Ammoniten des Rhat (Neues Jahrb., Bd. II. p. 1), 1895.

Quenstedt, F. A., Ueber die vorzliglichsten Keunzeichen der Nautileen (Neues Jahrb., p. 252),
1840. — Petrefactenkunde Deutschlands, I. Cephalopoden. Tubingen, 1849. — Der Jura. Tubingen,
1858.— Die Ammouiten des schwabischen Jura, Bd. I.-III. Stuttgart, 1885-88.— Remele, A., Zur
Gattung Palaeonautilus (Zeitschr. deutsch. geol. Gesellsch., Bd. XXIII. p. 1), 1881.— Strombolituites,
etc. (ibid. pp. 187, 478), 1881. — Reynes, P., Monographic des Ammonites. (Text' incomplete),
1879. — Roemer, F. v., Lethaea Geognostica. I. Lethaea Palaeontologica. Stuttgart, 1880-83. — Das
rheinische Uebergangsgebirge. Hannover, 1844. — Ryckholt, Baron de, Notice sur les genres Nautilus,
Vestinautilus, etc. Brussels, 1852. — Sandberger, G., Beobachtungen liber die Organisation der
Goniatiten (Jahrb. Ver. Naturk. Nassau, Bd. VII. p. 292), 1851.— Sandberger, G. and F., Die Ver-
steinerungen des rheinischen Schichten systems in Nassau. Wiesbaden, 1850-55. — Schlueter, C.,
Cephalopoden der oberen deutschen Kreide (Palaeontogr., Bd. XXI. XXIV.), 1872-77. — Schroder, H.,
Untersuchungen liber silurische Cephalopoden (Palaeont. Abhandl. Dames und Kay ser, Bd. V.
Heft 4), 1891. — Smith, J. P., Comparative Study of Palaeontology and Phylogeny (Journ. Geol,,
vol. V., No. 5), 1897.— Marine Fossils of the Coal Measures of Arkansas (Proc. Amer. Philos. Soc.,
vol. XXXV., No. 152), 1897.— The Development of Glyphioceras, etc. (Proc. Calif. Acad. Sci. [3],
vol. I. p. 105), 1897. — Steinmann, G., Ueber Tithon und Kreide in den peruauischen Anden (Neues
Jahrb., Bd. II. p. 130), 1881. — Steinmann, G., and Dijderlein, L., Elemente der Palaontologie.
Leipzic, 1890.— Stanton, T. W., The Colorado Formation (Bull. U. S. Geol. Surv., No. 106), 1893.
— Stoliczka, F., and Blanford, H. F., Fossil Cephalopoda of the Cretaceous Rocks of Southern
India (Mem. Geol. Snrv. India, Palaeont. Indica), 1861-66. — Suess, E., Ueber Ammoniten (Sitzungs-
ber. Akad. Wissensch. Wien, Bd. LII. p. 71 ; LXI. p. 305), 1866-70.— Tornquist, A., Die degenerier-
teu Perisphinctiden des Kimmeridge von Le Havre (Abhandl. Schweizer. Pal. Gesellsch., Bd. XXIII.
p. 1), 1896. — Toula, F., Eine Muschelkalkfauna am Golfe von Ismid in Kleinasien (Beitr. Palaeont.
Geol. Oesterreich-Ungarns u. Orients, Mojs. und Neumayr, Bd. X. Heft 4), 1896. — Uhlig, V., Die
Cephalopodenfauna der Wernsdorfer Schichten (Denkschr. Akad. Wissensch. Wien, Bd. XLVI.
p. 127), and Sitzungsber. Bd. LXXXVI. p. 86, 1883.— Voltz, P. L., Observations sur les Belopeltis
ou lames dorsales des Belemnites (Mem. Soc. Hist. Nat. Strasbourg, vol. III.), 1840 ; also Bull. Soc.
Geol. France, vol. XI. p. 40, 1839-40. — Waagen, W., The Jurassic Fauna of Kutch, vol. I. Cephalo-
poda (Palaeont. Indica, ser. IX.), 1873-76. — Salt Range Fossils. I. Productus Limestone Fossils;
Cephalopoda (ibid. ser. XIII.), 1879-88. II. Fossils from the Ceratite Formation (ibid. ser. X1IL),
1895. — Wahner, F., Beitrage zur Kenntniss der tieferen Zonen des uuteren Lias der nordostlicheu
Alpen (Beitr. Palaeont. Geol." Oesterreich - Ungarns u. Orients, Mojs. und Neumayr, Bd. II., IX.),
1882-95. — Wagner, A., Fossile Ueberreste von uackten Tintenfischen (Abhandl. Bayer. Akad.
Wissensch., Bd. VIII.), 1856-60. — White, C. A., Mesozoic Fossils (Bull. U. S. Geol. Surv., No. 4),
1884. — Whiteaves, J. F., Mesozoic Fossils, vol. I. (Geol. Surv. Canada), 1876-79.— Palaeozoic

SUB-CLASS i CEPHALOPODA— TETRABRANCHIATA

xnn-1'iinil flf imiiifh, and serve as prehensile and locomotive organs; in the
Dibranckiates //"'// area/rmed with //»<»/•>• ////// *nd-t /•>•.'

The Cephalopoda are the most highly organised, and include some of the
largest of all the AMlusca. They breathe by gills, and are exclusively marine.
Their nervous, circulatory, digestive, and reproductive systems, their muscula-
ture, and sense organs all exhibit remarkable differentiation a.- compared with
those of other Mollusks. A fleshy mantle, which is open above, encloses the
cavity which is occupied by the respiratory organs (the gills), and it also
serves as a covering for the reproductive, alimentary, and secretory systems,
the heart, and the principal blood-vessels. A large ganglionic mass (cerebral
ganglion) and sub-oesophageal ganglion connected by commissures are placed
around the oesophagus, and are surrounded by a cartilaginous enclosure in the
Dibranchiates, but in Nautilus this protects only the sub-oesophageal nerve
mass.

Recent Cephalopods were divided by Owen into two groups — Tetralranchiata
and Dibranchiata. The former is represented in the present fauna by the
solitary genus Nautilus, but the latter still comprises a very considerable series
of forms. A host of fossil Cephalopods abounded in the Palaeozoic and Meso-
zoic seas. The two largest groups of these, Ammonoidea and Belemnoidea, do
not afford any certain information regarding the number of gills, but the shells
of the former agree essentially with those of Nautili, while those of Belemnites,
on the other hand, are more like those of certain Dibranchiates ; hence it is
advisable to associate these fossil groups with the corresponding recent sub-
classes.

Sub-Class 1. TETRABRANCHIATA. Owen.1'

Cephalopods with four plum-like gills, and external, chambered shells. Amlniln-
t or u funnel divided ; ink-bag absent/ arms represented in exist in;/ XmiliU by lobes

Fossils, vol. III., ibid. 1884-97.— Contributions to Canadian Palaeontology, vol. I., 1885-89.— De-
scriptions of Fossils from the Devonian of Manitoba (Trans. Roy. Soc. Canada, vol. VIII. sec. 4),
1890.— Wh it field, R. P., Several papers in Bull. Amer. Mus. Nat. Hist,, especially I., No. 8, 1886 :
II., No. 2, 1889 ; III., No. 1, 1890 ; IX., No. 2, 1897.— Republication of Hall's 'Fossils, etc. (//,/,/.
vol. I., Part II.), 1895.— -Wright, T., Monograph on the Lias Ammonites (Palaeont. Soc.), 1878-86.—
Wilrtenberger, R., Studien iiber die Stammgeschichte der Ammoniten (Darwinistische Schrifte, No. 5).
Leipzic, 1880. — Zittel, K. A., Cephalopoden der Stramberger Schichten (Palaeont. Mittheil. Museum
Bayer. Staates, Bd. II.), 1868.— Die Fauna der alteren Tithonbildungen (ibid. Bd. III.), 1870.—
Handbuch der Palaeontologie, Bd. II., 1881-85.

1 Professor A. E. Verrill, whose knowledge of existing Cephalopods is not excelled by that of
any other malacologist, has kindly furnished the following and some other notes at the request of
Professor Hyatt : —

"The arms, together with the siphon ( unbulatory funnel) of Ceph.alopods. must be considered
as homologous with the foot of other Mollujca. The large nerves supplying these organs arise from
the pedal ganglia. In the early larval stages the arms arise as bud-like, paired lateral outgrowths at
the base of the large yolk-sac, while the rudiments of the "siphon (funnel) arise as two oblique pairs
of folds situated further back. The anterior pair of these folds eventually unite and form the
central or tubular part of the siphon, and the more posterior folds form tin- lateral or valvular
portions of the same organ. The rudimentary arms arise posterior to the mouth on the ventral and
lateral sides of the yolk-sac, and only surround the buccal region at a later stage. The yolk-sac
occupies the same relative position, behind the mouth, as the central part of the foot-area of ordinary
Gastropod larvae in the early veliger stages. Therefore the arms are muscular, lateral outgrowths of
this same foot-area. The two lateral rows of rudimentary arms are widely separated at h'rst by the
yolk, but during the absorption of this, they rapidly approach each other and converge around the
mouth."

2 Owen, R., Memoir on the Pearly Nautilus. London, 1 832.

506

MOLLTJSCA

SUB-KINGDOM VI

and numerous tentacles, which are without hooks and suckers.1 Cambrian to
Recent.

Our knowledge of the soft parts of the Tetrabranchiates is based entirely
upon the single existing genus Nautilus (Fig. 1049). The animal is contained in
the outermost compartment (living chamber) of the shell, the ventral portions
being on the external side. The body is short and thick, and the head
separated from the remaining portion. Around the mouth are about ninety

external filiform

* - --^ ^ajjJlFTmfi- ^ tentacles, placed

upon the edges of
lobes, and their basal
parts when con-
tracted are lodged
in fleshy sockets or
sheaths. The pair
of tentacles on the
inner or dorsal side
are fused so as to
form a thicker
muscular lobe or
hood, which serves
to close the aperture
of the shell when
the animal is with-
drawn into the

Recent ; Indian Ocean. Shell with contained living chamber. On

animal cut through along the median line, a, Mantle; &, Dorsal lobe of the ,1 r.^^^r.1 c.iVla nf

mantle ; c, Hood ; d, Hyponome, or "ambulatory funnel " ; c, Nidamental gland ; tne ventral S1QI

h, Muscle for attachment ; o, Eye ; s, Siphuncle ; t, Tentacles ; x, Septal chamber ^he head and ten-

tacles, but separated

from them, is a very thick muscular leaf, having the free edges external and
rolled in upon themselves (Fig. 1049, d). This is the so-called ambulatory
funnel of authors generally (hyponome of Hyatt), and its cavity is contracted
anteriorly and dilated posteriorly, where it opens into the branchial chamber.
It serves to conduct water which is taken by suction into, and then violently
expelled from the gill cavity of the mantle, thus driving the creature back-
ward by the force of reaction. Kerr2 suggests that the structure of the
infolding edges of the hyponome and the muscular character of this organ
would enable the animal to unroll and flatten it out so as to be available for
crawling. It is supposed to be homologous with the foot of Gastropods,
and this suggestion, if true, would show that it had not entirely lost its
normal functions in primitive forms of Cephalopoda.

On either side of the head, near the pair of lateral tentacles, is placed a
large eye of primitive structure, which is supported on a short peduncle. The
mouth is in the centre of the lobes and groups of tentacles, the tongue is
fleshy, and the radula armed with numerous rows of plates and hooks. The
remarkably powerful jaws (Figs. 1050, 1051) are largely composed of a dark,

1 Professor Verrill homologises the lobes of Nautilus with the arms of the Dibranchiata, and
the tentacles with the small lateral tentacles that fringe the arms in a number of deep-sea forms be-
longing to that sub-class.

2 Kerr, J. G., Anatomy of Nautilus pompilius (Proc. Zool. Soc., London, pp. 664-686), 1895.

FIG. 1040.

Nautilus

BUB-CLASS I

TETRABRANCHIATA

horny substance, only their points being calcified. Similar calcified beaks are
not uncommon in Mesozoic terranes, being found either associated with N.-niti-
loid shells or detached. The jaws belonging to Temnocheilus bidormtus from

FIG. 1050.

rpjxT jaw of Xmitiliix j,i,i,ij,;Hit.<.
A, Side view. B, Inferior aspect. 1/1-

FI.J. 1051.

Lower jawcif Xinit
pompiliu*, siile view. i

Fi... 1 1 »:.•_'.

Ternno

r7«,/;//«'s Mr-undo, Faiuv-i;j:.:m-n. M
k:ilk; Laineok. in-ar Hayn-utli. A, Upper
jaw, viewed from above. B, from the side.
C, from below.

the Trias were originally described under the name of Rhynclwlites and
I'lHirJiorhynchus (Figs. 1052, 1053); the common Jurassic and Cretaceous
forms are known as Rhynchoteuthis (Fig. 1054) and Palaeoteuthis, d'Orbigny.
The long, feather- like gills are disposed in two pairs at the base of the

hyponome, and between
them is the anus, closely
behind which is placed
the single or double
orifice of the generative
organs. In the female
there is found
at the base of
the gill cavity
a long, tri-
partite, nida-
mental gland,
which fuses

FIG. 1054.

Temnocheilus faV«r.>"'"s Hchloth.
( = C'onchorht/nchus avirostris, Blainv.).
Muschelkalk ; Laineck, near Bayretith.
Lower jaw viewed from above.

;>• Siilm mlin mis, Pict. and Lor.

Xeoeomian ; Voirons, France. A, Dorsal externally
aspect, showing in part the chitinous lateral
expansions. B, The calcareous beak seen
from below.

with
mantle.

the

The body is short, sack-shaped, rounded posteriorly, and enveloped by the
mantle. The base of the latter is prolonged at a certain point into a fleshy,
hollow cord or tube (the siphon), which passes through a rounded aperture in
each of the septa, and extends as far as the inner side of the apex in the
initial chamber. The fastening of the animal within the living chamber is
accomplished by two oval muscles situated on either side near the base of the
mantle. These muscles are attached to the inner wall of the living chamber,
and have corresponding, but very shallow impressions. They are connected
both dorsally and ventrally by a band of fibres, the annulus, which also leaves
its impression upon the shell. The form and position of the muscles for
attachment and the annulus are sometimes discernible on the casts of fossil
shells.

The shells of existing Nautili are coiled in one plane, and composed of

508 MOLLUSCA SUB-KINGDOM vi

several volutions, the outermost of which either envelopes all the earlier ones
(Nautilus pompilius), or leaves the umbilicus partly open (JY. umbilicatus}.
With the exception of the last half of the outer volution, which is occupied
by the animal as a living chamber, the shell is divided up into numerous
cavities or chambers by parallel partitions called septa, the mesal parts of
which are concave toward the aperture; and they are disposed at regular
intervals. The compartments thus formed are said by different authors to
be filled with air, gaseous, or even fluid matter, and all are traversed by the
siphon.1

This organ has dense walls and is probably not capable of any extended
movements inside of the surrounding calcareous parts which form the siph-
uncle. The relation of the siphuncle to the septal chambers in Nautilus has
not been sufficiently investigated to enable one to state distinctly what its
functions may be. The whole exterior of the mantle and siphon is encased
in a cuticle of horny matter, the remains of which are often found in the
living chambers and siphuncles of fossil forms as well. The shell itself is
composed of two layers, an internal and an external. The outer layer is
composed of imbricated laminae, is porcellanotis, light-coloured, and super-
ficially ornamented with red or brown transverse bands ; the inner layer is
nacreous, and composed of thin, parallel laminae, which are crossed by fine
rectangular lines. The septa likewise consist of a pearly layer, but are
covered over like the inner walls of the chambers with a very thin, opaque,
calcareous film. A large number of fossil shells have a structure similar to
the recent Nautilus. These are divided into several groups, characterised by
peculiarities of the initial chamber, and by differences in the suture lines,
siphuncles, sculpturing, and form of the aperture.

Our knowledge of the life -history of the Nautilus is very limited.
Although empty shells are cast ashore in great quantities in the Pacific and
Indian Oceans, the animal is rarely found alive. According to Eumphius, the
creature swims by ejecting water through the hyponome, and at the same time
holds the tentacles expanded horizontally, and the head protruded as far as
possible ; but when creeping, probably the head and tentacles are directed
downward.2 The shell is essentially alike in both cases. However, in
Nautilus pompilius, Willey has found that the females differ in having flatter
and more convergent sides, the males being stouter and more gibbous, which
is exactly contrary to the prevalent notions with regard to sex among shell-
bearing Cephalopods. The shell is supposed to serve as a hydrostatic appar-
atus, sinking when the animal withdraws into the living chamber, but sufli-

1 These conditions are described by Professor Verrill in the following note : — "The pericardium
of Nautilus pompilius communicates directly with the gill cavity by special pores, which are close
to the orifices of the nephridia, but do not unite directly with latter, as in most Mollusca. Water
can, therefore, pass directly into the pericardium and other coelomic cavities. The cavity of the
siphuncle appears to communicate directly with the pericardium, and hence with the gill cavity by
means of the special pores. Thus sea- water can readily pass into or out from the chambers of the
shell, to equalise pressure at varying depths, as in most marine Mollusca. These chambers are
imquestionably filled with fluid under normal conditions. But living as the animal does under
pressure at considerable depths, the fluid in the chambers is saturated with the gases in solution.
When the Nautilus is rapidly brought to the surface, some of the gas is liberated in consequence of
diminished pressure, and must occupy part of the space within the chambers by forcing out some of
the fluid. Hence the shell will float until the free gases within the chambers are absorbed or
otherwise eliminated. There is no evidence that free gases are ever naturally present in the living
chambers during life."

a Rumphius, G. E., d'Amboinische Rariteitkamer, p. 59. Amsterdam, 1705.

TETRABRANCHIATA §09

ciently buoyant to float itself and the animal when the head and tentacles are
protruded in the act of swimming. Moseley 1 confirms the observations of
Rumphius, but the animal he studied was drawn up by a dredge which had
been dragged on the bottom at a depth of 300 fathoms. This individual
swain in the manner described, but was not able to sink ; and this was
accounted for on the supposition that in rising from the bottom the sudden
expansion and rarefication of the contents of the air-chambers had interfered
with the action of the hydrostatic apparatus.

Nothing has yet been ascertained regarding the mode of reproduction
and development of the animal in Nautilus. The construction of the shell
in this genus, however, renders it probable that in the youngest stage a
perishable embryonal shell was formed, the presence of which is indicated by
a scar or cicatrix on the apex of the initial chamber. Hyatt describes and
figures a more or less wrinkled lump on the apex of several species of the
Orthoceratidae, which he regards as an embryonal shell or protoconch ; and
Clarke also figures one having a nearly perfect form. The former explains
the absence of the protoconch in most genera and in the recent Nautilus by
supposing it was usually membraneous or imperfectly calcified, and hence
easily destroyed.

As the animal continued to grow, it advanced forward by building out
the edges of the aperture and secreted new septa at regular intervals, each
one probably corresponding to a period of repose. A tubular prolongation of
the base of the mantle was formed at each period of progress, and this
remained behind in the first septal chamber and excreted the calcareous
matter that built the last segment of the siphuncle. Each septum bends
apically into a funnel around the origin of the siphon at the base of the
mantle, and this is continuous with a calcareous but more loosely constructed
and very porous wall that prolongs the tube begun by the funnel. This
porous wall or sheath coats the funnel on its external surface in the air-
chambers, but it continues alone apically beyond the funnel, and is inserted
into the spreading trumpet-like opening of the next preceding funnel. The
siphuncle is therefore a segmented, calcareous tube surrounding the siphon,
each segment crossing only one septal chamber and consisting of a funnel and
its connecting sheath.'2

In Nautilus the margin of the external opening or aperture is sinuous, the
concavities being the sinuses, the outward convexities the crests ; and the
single, median, concave bend on the venter is named the hyponomic sinus,
because it indicates the position of the hyponome. In some fossil genera
(Orthoceras) the aperture is often straight or simple (Fig. 1062); in others
the lateral margins are produced in the form of ear-like crests or lappets
(Lituites, Ophidioceras) ; and in some forms they approximate more or less,
forming contracted apertures.

The closure of the aperture is never complete, and may take place through
the inward growth of the lateral margins, as in Phragmoceras (Fig. 1087),
forming a direct dorso-ventral slit, or from the venter and the sides, as in

1 Moseley, H. X., Narrative of the Voyage of the Challenger, vol. I. p. 490.— Fischer, P., Manuel
de Couchyliologie, p. 473, 1880-87.— Willey, A., In the Home of the Nautilus (Natural Science,
vol. VI. p. 411), 1895.

2 Brooks, H., On the Structure of the Siphon and Funnel in Nautilus pompilius (Proc. Boston
Soc. Nat. Hist, vol. XXIII. p. 380), l88S.—Appelof, A., Die Schalen von Sepia, Spirula und
Nautilus (Kon. Svensk. Vetensk. Akad. Handling., vol. XXV. No. 7), 1895.

510 MOLLUSCA SUB-KINGDOM vi

Dimerites (Fig. 1084), producing a T-shaped opening; or, as in Hercoceras
(Fig. 1071), it may occur principally from the dorsum and venter, resulting in
a transverse aperture. The dorsal side of the aperture is, as a rule, occupied
by a crest, known as the dorsal crest (Figs. 1066, 1072, 1089). The_ position
of the hyponome is indicated by the large single opening and sinus at the
termination of the longer median slit of the aperture in shells with contracted
openings that obviously had this organ (Phragmoceras, Gomphoceras, etc.) ; but
in others like Hercoceras, which have no ventral sinus in the aperture, the
hyponome was probably absent or non-functional. The sinus in the lines of
growth, however (Fig. 1071), show that this organ was present in the pre-
ceding stages of development before the contracted apertures were formed.

Dr. Pompeckj states that contracted apertures occur only in the senile
stages of growth, and small shells having this peculiarity must be regarded as
dwarfs. This is certainly true of many species, and is probably also the case
with Hercoceras and the like. T-shaped apertures often show several accessory
sinuses and crests (Fig. 1085), which probably indicate the number of their
protrusible arms or tentacles. Most curved forms have the ventral sinus on
the arched external side (exogastric shells), but some have it on the concave
internal side, as in Phragmoceras, and these are called endogastric shells. The
interior wall of the living chamber, and volutions in recent and fossil
Nautiloids (Fig. 1073), are normally marked with fine transverse and longi-
tudinal lines. In the recent Nautilus a black superficial layer, composed in
part of organic matter, is deposited by the hood immediately in front of the
aperture on the dorsum.

The internal partitions or septa, which divide the volutions into chambers,
vary exceedingly in number among different species and also at different ages
of the same individual ; but they are tolerably constant as a rule, within the
limits of one and the same species, if specimens of the same age are compared.
They follow one another in regular succession, but as observed by Hyatt, the
intervals are relatively greater in the young, more constant in the adult, and
then markedly decrease in the oldest stage of development. Each septal
chamber (camera of Hyatt) was part of the living chamber until it was cut off
by a septum and left empty as the animal moved forward. Perfectly pre-
served shells may have the living chamber alone filled up with stony matrix,
since the sediment could only pass into the preceding chambers through the
siphuncle, or as a result of injury to the walls of the camerae. Nevertheless,
these last are seldom entirely empty, their interiors being frequently lined
with crystals of infiltrated calcite, quartz, celestine, baryte, pyrite, or with
organic excretions. Double septa occur in some forms (Actinoceras), arid in
others the camerae are sometimes secondarily partitioned off by intermediate
walls or pseudo-septa, which may either run parallel with the septa proper, or
at an angle with them, and are composed of two readily separable calcareous
lamellae. The origin of these pseudo- septa has been attributed to the
calcification of regularly arched membranes at the posterior end of the body.

The line of junction between the septa and inner wall of the shell is called
the suture. This is invisible externally, except when the shell-substance has
been broken or worn, or dissolved away, and it is seen most clearly on natural
casts. The sutures of Nautiloid shells follow, as a rule, simple, straight, or
slightly undulating lines. These undulations, when convex toward the apex,
are termed lobes, and the reversed or orad curves are the saddles. They are

SUB-CLASS i TETBABRANCHIATA 511

called lateral lobes when occurring on the sides, and when on the venter m
dorsum are termed ventral or dorsal /"/">• "//</ .«i,l,lh'.<. Tin- annular 1<>1<> is a
small median dorsal lobe, usually pointed and occupying the centre of the
main dorsal lobe. It is supposed to have had some relation to the correspond'
ing inflection or point of the annular muscle among the X<tii1iln'nli-n. In more
specialised shells it is associated with a conical inflection of the septum itself.
The curves are undulatory as a rule, but in some genera may be more or less
angular.

The position of the siphuncle does not enable one to determine which is
the ventral and which the dorsal side in most genera, but the hyponomic sinus
in the aperture and the curved lines of growth are an almost unfailing index
of the ventral side. The siphuncle is apt to change its position in the same
individual at different stages of growth, but in shells of the same age it is
approximately constant, and is available for diagnostic purposes in a number
of genera.

The siphuncle is variable in form and characteristics among Palaeozoic
genera, being tubular in some (Fig. 1061), or inflated in the interseptal spaces
in others, in such manner as to resemble a string of beads, or swollen discs
which are separated by narrow constrictions (Fig. 1077). When of consider-
able width, its cavity is partly filled up with thin calcareous lamellae (Fig.
1088), partly with the calcareous cones immediately to be described (Fig.
1056), or it is notably reduced by excretions around the interior of the
funnels forming peculiar annular swellings known as rings, and which are
generally composed of calcareous matter. The centre of the siphuncle in
these forms is usually kept open more or less perfectly by an axial tube
termed by Zittel the prosiphon (endosiphuncle of Hyatt), which will be con-
sidered more fully in the descriptions of Endoceras and Actinoceras. In
Diphragmoceras the siphuncle is septate like the shell. The upper parts of
these large siphuncles were more or less unobstructed near the living chamber,
and this part (the endoconal or siplmncular chamber of Hyatt) was doubtless
occupied by an extension of the mantle cavity, probably containing portions
of the viscera.

The funnel of the siphuncle as described above is simple in structure, and
is plainly directed towards the apex in all Xautiloids, with the exception of
Nothoceras and its allies, the funnels (?) of which are turned in the opposite
direction. The funnels, as a rule, are short and incomplete, although in
the early stages of development of many shells, and in the adult stage of
primitive forms they may be complete, extending from one septum to the next
following (Fig. 1056), or even to the second preceding this (Fig. 1055, (7).
When the funnels are complete they are always contracted apically, and
inserted one within the other. The siphuncle in most Xautiloids, as in the
existing Nautilus (Fig. 1074), is apt to be more or less dilated in the younger
stages, especially in the second and first air-chambers, and it is closed at the
end within the first air-chamber by what is termed the caecum. The external
shell is perforated by an elongated scar or cicatrix (Fig. 1073), closed by a
plate, against some part of which the bottom of the caecum impinges in the
interior. The presence of the cicatrix, as already stated, leads to the inference
that a deciduous embryonal shell or protoconch must have been present. The
shell on the apex is so much thinner than at later stages, and is so easily
abraded or destroyed, and the cicatrix itself in consequence so slightly marked

512 MOLLUSCA SUB-KINGDOM vi

even in perfect shells, that good examples are rarely found, and when met
with require careful preparation and close observation.

In some Palaeozoic Nautiloids with large siphuncles (Endoceras, Adinoceras),
the apical end of the siphuncle is solid and dilated to form the nepionic bulb
(Hyatt), and this sometimes practically fills the camerae, and besides being
very large in a number of succeeding chambers. The endosiphuncle expands
near the apex in these genera, and forms a good-sized conical perforation or
cicatrix, which is obviously open at its termination (Adinoceras, Nanno).

Closely coiled shells have the apical part bent so as to enclose a vacant
space (the umbilical perforation) in the centre of the whorls (Fig. 1070).
This is present in all the Nautiloidea having this mode of growth, although in
some genera it is very minute. The Nautiloid shell is invariably cone-shaped,
but this may be straight or curved, or coiled in open or closed spirals, but in
rare instances it is even screw-like, or similar to a Gastropod shell. Along
with perfectly smooth shells, or those marked only with fine growth-lines,
which in some rare cases may retain traces of their original coloration, there
are others with external transverse ridges, keels, rows of tubercles or laminae ;
but this ornamentation is of a simple kind, and never attains the degree of
complexity observed among the more highly ornamented forms of Ammonoids.

Classification. — Great importance has always been attributed to the external
configuration and curvature of the shell in distinguishing genera, and the
principal groups usually named Orthoceras, Cyrtoceras, Gyroceras, Nautilus, etc.,
have been founded upon such characters. Barrande emphasised in addition
the shape of the aperture, direction of the funnels, and structure of the
siphuncle, but considered these subordinate in most cases to the general
form, and the majority of writers have followed his example. Hyatt,
however, has regarded the general form and involution oi the shell as
relatively minor characters, and depends upon coincidence of structure,
outlines of the aperture, and especially resemblances in developmental
stages, as surer guides to the affinities of the species and characteristics of
the genera.

Terminology.1 — For sake of convenience, it is preferable always to speak of
the embryonal shell as the protoconch, and the later or epembryonic stages of
the shell as the conch, the term " shell " being really applicable to the entire
external skeleton inclusive of the protoconch. The history of the individual
and its shell can be divided into the following stages and sub-stages : — The
embryo or protoconch ; the nepionic stage or infancy, represented by the apical
part of the conch ; neanic stage or adolescent part of the more mature cone ;
ephebic or adult stage of the same ; and gerontic or senile stage with which it
terminates in a complete example.

All of these stages differ materially from each other as a rule, and it is
often convenient to divide them into sub-stages, connoted by the prefixes ana-,
meta-, and para-. Thus the nepionic can be separated into ananepionic, meta-
nepionic, and paranepionic, and it is often essential to treat the neanic and
gerontic stages in the same manner.2

1 [The following terminology, and the descriptions and arrangement of the groups from this
point onward have beon revised by Professor Alpheus Hyatt ; and certain alterations as well as
much new matter have been introduced into the translation of the original text_with the author's
permission. — TRANS.]

2 For a more extended discussion of terminology that can be advantageously used in descriptions
of shells of this class see Hyatt, A., Phylogeny of an Acquired Characteristic (1894), p. 422 et seq.

BDB-OLASS i TETRABRANCHIATA—-NAUTILOIDEA

The many different forms of N;iutiloi»l shells may In- grouped into .
lending types, as follows : — An orllini'nni- is tin; youm: of the straight a- \\vll as
many of the coiled forms. In this, although Mraight, the bands of growth
are broader on the venter than on the dorsuni, and there i> no hyponomic
sinus. A cyrtocone is the similar stagr which replaces or, as is oftener the
case, succeeds this and is curved. Both of these may have crests in tin; hands
of growth, on both the dorsum and venter, thus indicating that tin: young
animal did not possess a large hyponome. An ///y//ofv/v//-i,/,/< is the older stage
of a straight form, and is nearly or quite straight on both vmirr and dorsum ;
the bands of growth are approximately equal, but there is usually a hyponomic
sinus. Cyrtoceracones are shells curved like ( '////Wv /,/.->• on both venter and dorsum.
Gyroceracones are curved in a loose spiral like '/'///</'vras, the volutions being
sometimes in contact, but there is no impressed zone, i.e. the venter is not
involved by the overgrowth of the dorsum belonging to the next outer whorl.

The impressed zone in its primitive form is the longitudinal impression
formed in the dorsum by the contact of the whorls. This is divisible into
two kinds — the contact furrow, arising and lasting only when the whorls are
in contact ; and the dorsal furrow, arising through inheritance in the young
before the whorls come in contact. There is also a third modification, which
for the present may be called the persistent dorsal furrow. This occurs in the
free senile whorls of some shells, and is a remnant of the impressed zone.
Finally, there is a furrow arising only from contact in the old age of some
distorted Ammonoids, and hence may be called the gerontic contact furrow.
Cyrtoceracones and gyroceracones do not usually have impressed zones, but
an exception is furnished by Cyrtocems depressum.

X'intilicones are closely coiled shells having an impressed zone. This may
be only a very slight contact furrow, or a hereditary dorsal furrow deepening
by growth and involution, as in Nautilus. Torticones are asymmetrical spirals
like those of a Gastropod, either loosely or closely coiled. These may or
may not have impressed zones. Among Nautiloids they may be distinguished
as trochocemcones, etc., according to their form, and among Ammonoids as
tiirriliticones, etc., when more precise descriptive terms are required. A special
nomenclature is employed in describing the position of the siphuncle, w.hich
is of convenience in technical treatises, but may be omitted here. The septal
chambers have been termed camerae in the sequel, because this avoids any
assertion with regard to their contents, such as is implied by " air-chambers "
and the like. The less appropriate term " loculus " has been used with the same
meaning by Holm.

Order 1. NAUTILOIDEA.

Tin' cnnclix in-'' camerated orthocon^ <nnl <• ij rtocones in the young of jn-imftirf
forms, becoming cyrtoceracones lib- tin- ml nits of these same ancestral x//i7/x i,, tl,- ,/„„„,/ ,,f
more specialised and coiled shells. Apert n n-x li<n-'\ <t* « rnl>; n-iifrnl or A//y>«/<«,,//V
••^i a uses, and crests on the dorsum. Septa are concave alumi tin- ///<•.-•«/ /il<ni> /«c-,/ /•//>• fit,
"/"''• Sutures straight or undulat'-il, run I;/ n-ii/, xiih-«i,<!nl<ir I <>!>,>.•< <nn/ .«»</*//••>•, mxl these
are probably never acutely angular, as in flu' Ammonoidea. Each >•••»////,•/// ,if flu- .tijili-
uncle is composed of funnel and sheath as among primitii-r Anunnnniilx, hut th> fun ii' I
persists throughout life in the ontogeny of all forms (except perhaps Nothoceras).
around the oral openings of the funnel are present in the later stages of Ascoceras
Nothoceras?}. Apex cup- or saucer-shaped, and marked by a circular or i'l<>,i,/,if,,l <-,, n't,/
VOL. I 2 L

514

MOLLUSCA

SUB-KIXGDOM VI

or cicatrix, which is more or less compressed elliptical, never transversely elliptical or
depressed, and is sometimes hidden by the protoconch or its shrunken remnants.

The order may be subdivided according to the general external features of
the shell and structure of the siphuncle into five sub-orders, as follows, named with
reference to peculiarities of the funnels : — Holochoanites, Mixochoanites, Schistochoanites,
Orthochoanites, Cyrtochoanites. The characters of these different groups are denned
under their proper headings.

Sub-Order A. HOLOCHOANITES. Hyatt.

Funnels of siphuncular segments reaching from the septum of origination to the plane
of the next septum apicad or beyond this, or in some genera even to the plane of the second

I. DlPHRAGMIDA.

This group contains but one family, Diphragmidae, having the same characters as
the following unique genus : —

Diphragmoceras, Hyatt. Orthoceracones and cyrtoceracones having simple septa
and sutures as in Endoceratida, but siphuncle divided by tabulae alternating with the
septa of the camerated shell. Chambers of siphuncle empty, as are also the camerae.
Quebec Group.

II. ENDOCERATIDA.

Orthoceracones, cyrtoceracones, gyroceracones, and nautilicones having siphuncles of
variable diameter, but as a rule large in proportion to width of the shell. TJiey may be

empty or filled with internal

B c organic deposits, but are in-

variably tubular, and the
funnels completely shut off the
interior from the interiors of
the camerae. The latter are
without organic deposits.

Family 1. Endoceratidae.

Smooth or annulated ortho-
ceracones. Siphuncle always
more or less filled ivith organic
deposits.

Vaginoceras, Hyatt (Fig.
1055). Ordovician. Gamer o-
ceras, Conrad (Sannionites,
Hyatt ; Suecoceras, Holm).
Ordovician and Silurian.

Endoceras, Hall (Colpo-
ceras. Hall; Diploceras, Con-
rad), (Fig. 1056). Smooth
or annulated Orthoceracones.
Funnels reach from septum
of origination to the next
apicad of this, but .no farther.
Organic deposits in the form of endocoiies,

Fio. 1055.

A, Vaginocci-i'* (End.) duplex, Walilb. Ordovician ; Kinnekulle,
Sweden. Much reduced. B, V. commune, Wahlb. Ordovician - Oranien-
baum, Russia. The anterior endocone of the siphuncle is filled up
with matrix so as to form a dart (" Spiess "). V2. C, Diagrammatic
longitudinal section of the last, showing siphonal funnels. D, De-
tached camera of Vaginoceras with long siphonal funnel. (Figs. C
and D after Dewitz.)

Septa pass entirely around the siphuncle.

SUB-OKDKK 1!

HOLOCHO AN IT ES— M I XOCHO AN ITES

515

and taper off at the centre into a spin- that is .-oim-tiinrs tubular and 1
tlattrurd and elliptical. This is tin- .,/»/•..•.•//,/,/'/»•/»?.
Ordovician and Silurian.

Narthecoceras, Hyatt. Long, cylindrical, stafl'-likc
orthoceracones. Siphuncle large and filled with organic
deposits having a radiating fibrous structure like the
guard of a Belemnite. Endocones and an endosiphuncle
developed. Septa continuous around the siplnmrlr.
Ordovician.

Nanno, Clarke. Similar to the preceding, hut endo-
siphuncle present only at the apical end. Siphuncle
close to the shell, so that sutures appear to l>rn<l
apically into a lobe passing around the siphuncle.
Trenton Limestone.

Family 2. Piloceratidae.

Shorter and stouter orthoceracones and cyrtoceracones
with relatively larger siphuncles than in Endoceratidae,
and more variable in their internal deposits. Septa are
more concave and sutures more sinuous. Camerae empty
and funnels similar.

Piloceras, Salter. Breviconic cyrtoceracones with
very large siphuncle and well - defined endocones.
Ordovician.

iollo\v, or

FIG. 1056.

Endoceras protfiforme, Hall, onlu-
vician ; New York. Longitudinal
section showing funnels and endo-

Family 3. Cyrtendoceratidae.

Gyroceracones and nautilicones having large siphuncles filled with organic deposits or
empty, but with endocones obscure or absent, and no endosiphuncles.

Cyrtendoceras, Kemele. Gyroceracones with siphuncle near the dorsum and lillrd
with calcareous deposits. Ordovician.

Sub-Order B. MIXOCHOANITES. Hyatt.

Orthoceracones and cyrtoceracones having expanded living chambers with contracted
apertures in the gerontic stage of specialised genera. The oldest septa are bent ,s7/"/-y///
orad, forming a series of dorsal saddles, and the siphuncle becomes highly modified.
Primitive genera have the septa deeply concave or approximately sub-conical, the siphuncle
small and empty, and the septa sometimes more or less imperfect on the ventral side in the
gerontic stage. Specialised forms have siphuncles with short, straight funnels in flic
young, and in the ephebic stage collars are built around the oral openings, thus becoming
parallel to some forms of Goniatitidae that have similar composite funnels.

Family 1. Ascoceratidae.

Cyrtoceracones, smooth or annulated. Siphuncle with long funnels only in the young
and later stages of primitive genera, but cottars are added in later stages of specialised
forms, and segments become nummuloidal in gerontic stage. Septa often more or less
imperfect around siphuncle and on the ventral side.

Choanoceras, Lindstr. Sections depressed elliptical. Gerontic stages have no
saddles, and living chamber uncontracted. Ordovieian and Silurian.

516

MOLLUSCA

SUB-KINGDOM VI

Aphragmites, Barr. Only gerontic living chambers known ; these are similar to
those of Ascoceras, but have no internal sigmoidal dorsal saddles. Silurian.

Ascoceras, Barr. (Figs. 1057, 1058). Gerontic living chambers
internally contracted by the formation of large sigmoidal saddles,
and septa more or less incomplete ventrally. Siplmncle with
funnels only in the young, the collars in ephebic stages becoming
immnmloidal and often incomplete in old age. Aperture open.
Silurian.

Glossoceras, Barr. Known only by gerontic living chambers
which are like those of Ascoceras, except that aperture has dorsal
and lateral crests. Silurian.

Volborthella, Schmidt. Minute orthoceracones with conical
septa, small siphuncle, perfectly plain upon the surface of the
septa. Living chamber flaring and imcontracted. Lower Cam-
brian ; Finland, Esthonia. St. John's Group ; Nova Scotia.

FIG. 1057.

Ascoceras manubrium,
Lindstrom. Silurian ;
Gottland. 1/2- (Re-
stored after Lindstrom.)

FIG. 1058.

Ascoc-eras bohemwum, Barr. Silurian (6tage E) ; Kozorz, Bohemia. .4,
Specimen with shell partially preserved. B, Cast of living chamber detached
from preceding portion. C, Longitudinal section, w, Living chamber ;
c 1-4, Camerae ; I 1-4, Saddles contracting the living chamber. 1/1 (after
Barrande).

Family 2. Mesoceratidae.

Depressed elliptical cyrtoceracones, known only by their gerontic living chambers, and
affinities therefore uncertain. They are globular at this stage, and have highly contracted,
transversely elongated, and approximately dumb-bell-shaped apertures.

Mesoceras, Barr. Aperture with very shallow hyponomic sinus. No internal
gerontic sigmoidal septa. Silurian.

Billingsites, Hyatt. Aperture without hyponomic sinus. Gerontic living cha ml >»• r
partly filled by dorsal sigmoidal saddles as in Ascoceras, but septa complete on the
ventral side. Silurian.

Sub-Order C. SCHISTOCHOANITES. Hyatt.

Funnels usually more or less imperfect, present on the internal side, and absent or
split on the outer side.

This group will be better understood after the publication of Professor W. B.

SUB-ORDER D SCHISTOCHOANITES—OETHOCHOANITES 517

Dwightfs remarkable genera •''•"'" i'"1 <tMieb.M- c,r<>\\\> m-ar l'oiighki-1-p...ii-, NVw V-.rk.

They an- ]>rol talily diiv.-tly <Miin«-ctrd with //»,/.«•/*»»./////»•>•. Tin- lypii-al form of tin-
sul '-order is, of course, Conoceras, I'ronn.

Oyrtocerina, Bill. l'.iv\ -iconic cyrtoceraeones. Siphiinc]<-
large, on tin- connive side and empty, luit having inti-nial ridg<->
nli'-rnatiiig with septa of tin- camera.-. These ridges appear to
indicate allinily with ('minn'm*. Ordovician.

Conoceras, Bronn (Bathmocercu, Ban. . !•'!-. 1059). Brevi-
conic ortnoceracones, known only in their later Mage.- of dev»-l<»j»-
meiit. Sijiliiincle <if niddci-atc >i/.c, suli-\-fiitran. Kunin-ls
reaching half-way across «-a<-h cann-ra, >tiM-j.ly inclin.-«l orad,
and split on the outer side. Closure of the walls effected l.y
a plate extending IVom tin- apical opening of each fmmrl
through the I'linnd iiself orad to the apical opening of the n.-\t
beyond, and projecting into the interior as a flattened fold, F[(.

which is incomplete or open along the central axis. Thoe conoceras pro
internal collars or flat semiconical rings have l»een described as Barr. (H.iovici.i
complete cones (Dwight). Ordovician. SinfK' "'

Sub-Order D. ORTHOCHOANITES. Hyatt.

Gerontic stages have uncontracted volutions and open apertures, except in a few
uncoiled phylogerontic genera. Siphuncular segments may be slightly nummuloidal,
fusiform or tubular, but are never markedly nummuloidal, nor are the funnels bent
sharply outwards as in Cyrtochoanites. Deposits formed only in the siphuncles of Ortho-
ceratidae and Kionoceras, and in them they are irregular and no endosiphuncles occur ;
other genera have empty siphuncles. Funnels, as a rule, both longer and straighter than
in Cyrtochoanites, and in Aturia almost equal to those of Holochoanites.

This group includes the greater number of Nautiloid forms, passing from the
smoothest to the most highly ornamented of Palaeozoic shells, continuing in the Trias
as nautilicones of complex ornamentation, and terminating with smooth shells that
range from the Jura to the present time. The sutures become more sinuous and com-
plex in one of the subdivisions than in all other Nautiloids. The increase in numlu-r
of lobes and saddles begins in the Trias with Cbjmenonautilus, and ends with Af>!ri<.<
in the Tertiary.

I. ORTHOCERATIDA.

Orthoceracones and cyrtoceracones with smooth or ornamented shells, and not as a
rule contracted in gerontic stage ; apertures open throughout life. Although often short,
none are brevicones, strictly speaking. Section circular or elliptical, very rarely oval.
Siphuncle with slightly nUmmuloidal, fusiform, or tubular segments, and generally near
the centre.

Family 1. Orthoceratidae.

Section circular or compressed, living chamber ungontracted or only slightly so,
inxl aperture always open. Surface smooth or with only transverse bands, rarely
longitudinal striae, never longitudinal ridges. Siphuncle small (except in Baltoceras),
segments fusiform or cylindrical, never nummuloidal. Deposits when present irregular,
and gathered about the funnels as in Cyrtochoanites; no definite endosiphuncles ever
formed.

Baltoceras, Holm. Siphuncle large, but with short, straight funnels, and sheaths
as in Orthoceras. Ordovician.

518 MOLLUSCA SUB-KINGDOM vi

Orthoceras, Breyn (Figs. 1060, 1061). Long tapering orthoceracones and cyrto-

FIG. loco.

Orthoceras intermedium, Marklin. Silurian ;
Gottland. Longitudinal section showing
siphuncle, septa, and pseudosepta ; camerae
filled up with calcite.

FIG. 1061.

Orthoceras Michelini,
Barr. Silurian ; Kozorz,
Bohemia. Longitudinal
section showing short
siphonal funnels.

FIG. 1062.

Geisonoceras timid-urn,
Barr. sp. Silurian ; Loch-
kow, Bohemia.

ceracones, smooth, or with only transverse striae and growth

bands. Siphuncle generally larger than in Geisonoceras, centren

or slightly dorsad of centre. Deposits when present gathered

about the funnels as in Annulosiphonata. Silurian to Trias.

Geisonoceras, Hyatt (Fig. 1062). Similar
to the last, but sides spreading more rapidly,
and siphuncle empty, centren, or slightly
ventrad of centre. Ordovician to Carbon-
iferous.

Protobactrites, gen. nov. Long pencil-
shaped orthoceracones and cyrtoceracones, circular or compressed
elliptical in section, ornamented with transverse and sometimes
longitudinal striae. Siphuncle tubular, centren or near the centre.
Truncation occurs in some species, and others are more or less
transitional to Bactrites among the Ammoiioids. Type P. (Orth.~)
styloideum, Barr. sp. Silurian to Carboniferous.

Family 2. Cycloceratidae.

Orthoceracones and cyrtoceracones having annuli with
striae or bands of growth at all stages ; longitudinal ridges, when
present, more or less discontinuous. The earliest forms often have
large siphuncles, and are apparently more directly connected with
primitive Endoceratida than with Orthoceratidae.

Protocycloceras, gen. nov. Annulated orthoceracones and cyrto-
ceracones without longitudinal ridges. Siphuncle large. Type P.
(Orth.) Lamarcki, Bill. sp. Ordovician.

Cycloceras, M'Coy (Dictyoceras, Heloceras, Eichw.). Annu-
lated orthoceracones and cyrtoceracones with discontinuous longi-
tudinal ridges. Siphuncle generally tubular or with fusiform
segments; deposits when present irregular as in Orthoceras.
Annuli often become obsolete in paragerontic stages. Ordovician
to Permian.

Da wsonoceras, Hyatt (Fig. 1063). Similar to Cycloceras, but
frilled bands of growth between and on the annulations, the frills

FIG. 1003.

Davsonoceras annida-
tum, Sowb. sp. Silurian
(E) ; Viscocilka, Bo-
hemia. Terminal por-
tion showing shell of
living chamber and
sectioned camerae (after
Barrande).

having prominent

SUB-ORDKK I)

OKTHOCHOANITKS

:, 1 1»

sometimes forming more or less discontinuous longitudinal rid^«->. Silurian and
Devonian.

Ctenoceras, Noetl. Cyrtoceracom-s likr / >« n-sonoceras </"/<•<, I'.an. .-]•., hut with
fine longitudinal ridg<- Mweun tin- annuli, and living chamber with ilm-,- intermfl
folds or processes— one median dorsan, and a paii -on ih.- v.-nti-r. Siph uncle dorsad
of centre. Ordovician.

Family :?. Kionoceratidae.

Orthoceracones and cyrtoceracones with more or less well-marked continuous longi-
tudinal ridges, and either with or without annulations. Spinous processes or tubercles
often appear at the intersections of the longitudinal and transverse
bands of growth. Siphuncle with faintly nummuloidal, fusiform,
or tubular segments.

Kionoceras, Hyatt. Longitudinal ridges present as a rule
only in the earlier stages, after which inconspicuous annuli
appear, hut with some few exceptions hecome obsolete before the
ephebic stage. Silurian to Carboniferous.

Spyroceras, Hyatt. Very long, slender, annulated shells,
with more or less prominent longitudinal ridges in the ephebic
stage. Ordovician to Carboniferous.

Thoracoceras, Eichw. (Melia, Eichw.), (Fig. 1064). Like the
last, but with more or less spinous longitudinal ridges. Silurian
to Carboniferous.

II. PLECTOCERATIDA.

Orthoceracones, gyroceracones, and very discoidal nautilicones
with comparatively slight impressed zone. Volutions of gerontic
stage often have a centrifugal tendency, becoming sometimes
straight and even bending slightly in the opposite or ventral
direction. Shells annulated or costated, and often with longi- Flo 10(.4

tudinal striae or fine ridges, especially in the young, but these Thomcocem.< corbuintum,
generally disappear before the ephebic staqe. Siphunciilar sea- Barr. sp. Silurian (Stage
,.,,-£ E);Dvoretz. Bohemia (after

ments slightly nummuloidal, fusiform, or tubular. Harrande).

Family 4. Tarphyceratidae.

Orthoceracones, cyrtoceracones, gyroceracones, and nautilicones, wm$rf»*fd <>rn} ///
section, venter narrower than the dorsum. Shell smooth or sometimes witli primitive fold-
like costae. Siphuncle empty, tubular and ventrad of centre.

Aphetoceras, Deltoceras, Barrandeoceras, Tarphyceras, Hyatt ; Planctoceras, Eury-
stomites, Schroder ; Falcilituites, Remele. Ordovician. (For descriptioiLS see Hyatt's
Phylogeny, 1894.) Eurystomites and Tarphyceras are wholly nautilicoiu-s, the remain-
ing genera either cyrtoceracones or gyroceracones. Orthoceracones represented by
genera at present undescribed.

Family 5. Trocholitidae.

Nautilicones resembling those of the preceding family, and not easily distinguished
from them in the young. As a rule they have excessively broad volutions with reniform
section and an impressed zone at a very early age; the siphuncle is then ventrad of the
centre, but in the ephebic stage it is tubular and dorsad of centre.

Schroederoceras, Litoceras, Trocholitoceras, Hyatt ; Trocholites, Conrad (Palaeo-
nautilus, Palaeoclymenia, Remele). Ordovician. Discoceras, Barrande. Ordovician
and Silurian.

520

MOLLtfSCA

SUB-KINGDOM VI

Family 6. Plectoceratidae.

Gyroceracones, nautilicones, and torticones having annular costae from the neanic

stage until late in life, and in
some genera, more or less pro-
minent longitudinal ridges,
which usually disappear in
the ephebic stage. Siphuncle
ventrad of centre.

Plectoceras, Hyatt, Ordo-
vician and Silurian. Sphy-
radoceras, Hyatt (Peismoceras,
Systrophoceras, Hyatt), (Fig.
1065). Silurian and De-
vonian. The first is gyrocera-
conic, with some discoidal
nautilicones, and the second
is almost exclusively torticonic
of the troclioceran type.

Family 7. Ophidio-
ceratidae.

FIG. 1065.

Sphyradoceras optatum, Barr. sp. Silurian
(Etage E) ; Lochkow, Bohemia (after Barrande).

Discoidal nautilicones,
costated from the neanic stage
onward. Volutions of the
young small and numerous.
Section during ephebic stage generally compressed, venter narrower than
the dorsum. Siphuncle tubular, small.

Ophidioceras, Barr. (Fig. 1066). Nau-
tilicones with straight lateral costae and
raised bands on the venter, and longitudinal
ridges in the young. Siphuncle dorsad or
Ventrad of centre during ephebic stage, but
ventrad during nepionic. Gerontic aper-
tures with prominent dorsal and lateral
crests, and very deep hyponomic sinus.
Silurian.

Homaloceras, Whiteaves. Cyrtocera-
cones with section similar to that of Ophid-
ioceras,, venter narrow and channeled,
bordered by crenulated ridges ; the dorsum
gibbous and rounded. Siphuncle near
the venter. Devonian.

FIG. 1066.

Ophidioceras simplex, Barr.
Silurian (E) ; Lochkow, Bohemia.
Vi (after Barrande).

Family 8. Lituitidae.

Excepting the supposed ancestral, primitive genus, Cyclolituites, this
is a series of phylogerontic uncoiled forms with an extreme modification
in the almost completely uncoiled Rhynchorthoceras. Apertures quite

distinct from those of the preceding family ; hyponomic sinus shallower, Montf. Ordovician
., j ii i * i • 7 drift ; East Prussia.

there are narrow ventro-lateral crests, and small lateral sinuses and i/0 (arter Noetiing).

FIG. 1067.
Lituites lituut

sri'.-oKDKK I)

ORTHOCHOANITES

521

crests, s&me forms having altogether «.< many as fito sinuses "/<"' , >'/'/////<,//•/.

tiifnifm- mill iiaitiillii large.

i'ii,-l,ilitnit,:<, Iveinel.' ; Litiiit,:*, I'reyii I-'JLT. 1"<;7 : J /"/• ////«./•••/>/.<, //<»/„.
llv.itt. Ordovician. J //<•/.</ /•/(/•/>m«, Boll ; IfliipH-lmi-thoceratf Kernel.'-. ()I-«IM\ ician an-l
Silurian. (For re-descriptions see Hyatf s /'/<///•"/• ////.

III. I'I.KI BONAUTItTDA.

Comparatively smooth nn uti/ini/i,.^ (I,,- ///•////////-. ./»•/,,-/••> il/'.<n,i,l,il I,, if hui/imi nj, t<,
some highly involute shells in the Trin*. Tin' l«t,r M, .«>-.,,!<• ,1,1,1 y ',/•//,/,// x/,,//,
nil ilnji/ij iiti-nliitr. XOHII- of tin-. Triassic ClydonautHidck /<"/•, ,„,,,-. sinuous tutw

n iinnti-r a a mini- of lobes and s<t<l<ll'* tlmit «mi ntln-r A"'"'///«/'/.<, null tins cum fill .: it a
•jii /-x/x/x, <i!tl«>n<ili to a, lesser degrt'f, n/noml tin .//'/v/xs/V, ('ntn,;,,,!.-;. <m<l Ti-rtin ril form*.
tiihiilnr mill x///^//, with most! if xlmrt fniun-l.< except in Aturi'i. /'•//./-,- //«,/ «»/-.

K;iniily 9. Grypoceratidae.

Primitive forms have di&coidal volutions ?'•//// /•»/•// x//,//y/c .</»/// /•.>-, ///// af< .^n-,-, ,,/,,/
In! i /I ml uti; shells having more complex sutures. Tlie latter have prominent /•»/)//•<»/
*, t< 1, 1 1,:* sometimes divided by a lobe, and large lateral and dorsal lobes. All genera
save one known to have annular lobes. Shells less hiylilii oni<n,t,',it<'<l flum /// j,i;;;;lin,j
f n in if it, n ml sutures simpler than in the next following.

SynngoceraSj Hyatt. Discoidal with primitive, approximately tubular, or .slightly
compressed volutions. Surface marked by longitudinal ridges, sometimes intersct-tiug
the transverse lines so as to produce a cancellated surface. Sutures with faint ventral
saddles, slight lateral and dorsal, and minute annular lobes. Siphunrlr Any .-mall
and near the venter. Trias.

Grypoceras, Hyatt. Volutions more or less deeply involved, but umbilk-u- <>pni,
the venter narrow and often channeled. Sutures
with narrow, sometimes deep ventral lobe, broad,
sweeping lateral lobes, and deep dorsal with
annular lobes. Siphuncle dorsad of centre.
Trias.

Family 10. Clydonautilidae.

Jiave folds in some species, and all are
ili-i jilii i a ml a 1 1' I'.rcept the primitive genus Clymeno-
in i n til n^. Lateral lobes of sutures more or less
//••if/ n ml often sub-angular, suggestive of the
e among Ammonoids. SOUK- //A//////
a ml involute species have the umbilical
lobes exposed on the sides, and an additional pair
of litt'riih developed near the vent>/\ tin* mnL-i/ni
three pairs of lobes on each side. The compressed
volutions, narrow venter, and aspect of the young
mill primitive forms seem to indicate close djini/fii
with the Grypoceratidae, but only a few species of
luft Mesozoic timeare knon-n to hnr<' <ninnl<tr lobes.

FlG- 10C8g

S1>'

Clymenonautilus, gen. nov. Smooth, dis-
coidal shells with more or less compressed J
volutions, and narrow convex venter. Sutures

with prominent ventral saddles, one pair of deep lateral lobes, and large marginal sa< Idles.
Siphuncle supposed to be near the venter. Type C. (Xaut.) Ehrlichi, Mojs. sp. Trias.
Mojs. Deeply in\<ilved nautilicones with compressed volutions,

522 MOLLUSCA

SUB-KINGDOM VI

narrow concave venter, and umbilicus small or closed. Sutures with prominent
ventral saddles undivided by ventral lobes in adult shells. Trias.

Hercoglossa, Conrad (Enclimatoceras, Hyatt), (Fig. 1068).
Deeply involute, with sutures like those in Glyphioceratidae, but
the ventral saddle not divided by even the shallow lobe usually
found in that family. Annular lobes present only in some
species. Siphuncle small, centren or dorsad of centre. Trias to
Tertiary.

Pseudonautilus, Meek. Similar to Hercoglossa, but with lobes
on the venter, and two saddles on either side. Large annular
lobes present. Jura.

Aturia, Bronn (Fig. 1069). Similar to Hercoglossa, but with
large siphuncle close to the dorsum from an early stage onward,
and funnels very long and larger than in any genus of Mesozoic

or Tertiary Nautiloids. Eocene and Miocene.
FIG. 1069.

Aturia Aturi, Bast. sp.

Miocene; Bordeaux. TTT "RVTTPFR ATTT»A

Shell broken open to 1V> ^TICERATIDA.

show siphonal funnels.

Cyrtoceracones, gyroceracones, and nautilicones having shells

covered with more or less projecting bands of growth which often become sinuous or develop
into spout-like, spinous, or nodose prominences. In the more specialised shells these are apt
to be confined to the venter. TJie frills in the bands often form coarse longitudinal ridges.
Siphuncle tubular or slightly nummuloidal, and commonly ventrad of centre.

Family 11. Halloceratidae.

Orthoceracones and cyrtoceracones having depressed elliptical or subtrigonal section*,
venter broader than the dorsum. Shell with closely set and frilled projecting bands of
growth, having large ring-like bands at intervals that sometimes expand so as to form
wide collars. The highly specialised nautilicones may have a row of large nodes on
either side springing from the bases of large spout-like spines. Siphuncle tubular, small,
and near the venter.

Zitteloceras, Hyatt. Cyrtoceracones of depressed elliptical section, the venter
narrower and more gibbous than the dorsum. The layers finely frilled and closely
set in the intervals between more prominent annular bands. Ordovician to Devonian.

Halloceras, Hyatt. Gyroceracones of sub-trigonal section, the venter broad and
dorsum sub-angular, with one row of large nodes at each of the ventro -lateral angles.
Devonian.

Family 12. Ryticeratidae.

Cyrtoceracones and gyroceracones resembling Halloceratidae, but much larger, n-/tli
coarser crenulated bands, and often with rows of spout-like spinous processes which some-
times form coarse longitudinal ridges. Siphuncle more or less nummuloidal, and larger
than in Halloceratidae.

Ryticeras, Hyatt (Rutoceras, Hyatt), Cophinoceras, Slrophiceras, Hyatt. Devonian.

V. RHADINOCERATIDA.

Cyrtoceracones, gyroceracones, and nautilicones having smooth or spinous longitudinal
ridges in the young, which become large and fluted in some genera, but disappear in
others. Ridges more or less sporadically combined with fold-like annulations, thus
suggesting direct descent from the Kionoceratidae.

SUB-ORDER t) ORTHOCHOANITES 523

Family 13. Bhadinoceratidae.

Primitive discoidal gyroceracones and nautilicones with stout ml „<;,,,, .. ,-:,-<• n I, ,,- >.:•
<!' l>ressed elliptical in section, but becoming reniform in later >•/-/</•> •./' nmitilir
Shells with longitudinal ridges and sometimes annular folds in tl» //«///M/, /,/// ,,ff. n
smooth in ephebic stage. Sutures with ventral, lateral, and dor ant /«/*-.„, /,/• almost
straight. Siphuncle nummuloidal and often dorsad of centre. Annular lobes known to
be present in specialised forms.

Bhadinoceras, Nephriticeras, Hyatt. Devonian.

Family 14. Trigonoceratidae.

Gyroceracones and nautilicones having at some stage or ////•<///, //,„/'/ life trigonal
volutions, a more or less concave venter, and generally fluted shell. Sutures with ventral
saddles in the young, becoming divided by shallow lobes in later stages, and in some genera
the dorsal lobes of the young become divided subsequently by dorsal saddles. Gerontic
living chamber occasionally free near the aperture. Annular lobes observed in only one
species (Apheleceras disciforme). Young have longitudinal ridges roii<ih>-ni<I bij transverse
bands as in Thoracoceras. Siphuncle small, ventrad of centre.

Trigonoceras, M'Coy ; Coelonautilus, Foord (Trematodiscus, Meek ; Trematoceraa,
Hyatt) ; Subclymenia, d'Orb. ; Stroboceras,
Apheleceras, Diorugoceras, Ephippioceras,
Hyatt. Carboniferous. All nautilicones
but the first, which is gyroceraconic.

Family 15. Triboloceratidae.

Gyroceracones and nautilicones similar
to Trigonoceratidae, and with concave
venter at an early stage or until late in
life. The venter afterwards becomes more

or less elevated, and in most species convex. Fio. 10:0.

Sutures also similar, but annular lobes VestinauMus Koniwki, <l'0rb. 81,. Carboniferous
nrp <nrt><ipnt in nil t~hp 'nfit/tiJirn'nfl<i <tniip Limestone; Tournay, Belgium. < >ral and lateral

are presen in all we nautilicones save aspects of y'oung indlftduait With umi.iiical perforation.
Coloceras.

Triboloceras, Hyatt ; Vestinautilus, Ryckh. (Fig. 1070) ; Planetoceras, Stearoceras,
Coloceras, Hyatt. Carboniferous.

Family 16. Rhlneceratidae.

Gyroceracones and nautilicones like Thoracoceras in nepionic stage, but subsequently
becoming biangular in section, and generally developing solid, more or less tetragonal
volutions. Longitudinal ridges and flutes also developed, but more uniform in size than
in the preceding family, and venter always convex. Annular lubes present in all
nautilicones so far as known.

Bhineceras, Lispoceras, Thrincoceras, Phloioceras, Discitoceras (Discites, M'Coy),
Leuroceras, Phacoceras, Hyatt. Carboniferous.

VI. HERCOCERATIDA.

Primitive shells have projecting bands of growth and processes similar to those of
primitive Ryticeratida, but less numerous, being present in only one row, and evolving

524

MOLLUSCA

l- vIXGDOM \I

more rapidly into nodose or symmetrical, spout-like, spinous processes. More specialised
forms are tuberculated as in Ryticeratida, but there are never more than three rows of
nodes on either side, and these are regularly distributed — one on the umbilical shoulder,
another on the ventro-lateral angle, and the third close to the median ventral line.
Annular lobes absent except in a few Triassic forms. Siphuncle generally more or less
nummuloidal.

Family 17. Hercoceraticiae.

Cyrtoceracones, gyroceracones, nautilicones, and torticones having depressed elliptical,
sub-quadrate, or trapezoidal sections. Aperture has two deep sinuses with projecting edges
at the ventro-lateral angles, and these are usually persistent, forming two lines of more or

FIG. 1071.

Ptenocerus (Gyr.) vl
Barr. sp. Silurian

Hercoceras minim, Barr. Silurian (Etage G) ; Hlubocep, Bohemia (after Konieprus, Bohemia.
Barrande). (after Barrande).

J/i

t-UJce processes. Sutures with ventral, lateral, and dorsal lobes. Siphuncle
ventrad of centre.

Hercoceras, Barr. (Fig. 1071); Trochoceras, Barr.; Ptyssoceras, Ptenoceras (Fig.
1072), Anomaloceras, Hyatt. Silurian.

Family 18. Tainoceratidae.

Discoidal nautilicones with more or less massive volutions which at some stage or
throughout life are trapezoidal in section, tuberculated, and without well-defined lateral
and umbilical zones. Sutures have ventral, lateral, and dorsal, but no annular lobes.
Spinous processes are complete, never spout-like. Siphuncle small, tubular.

Temnocheilus, M'Coy (Endolobus, Meek ; Cryptoceras, d'Orb.). Section trapezoidal
throughout lii'e, and one row of persistent spines and nodes on either side at the
ventro-lateral angles. Devonian to Carboniferous.

Foordiceras, Hyatt. Permian. Metacoceras, Coelogasteroceras, Hyatt. Carbon-
iferous. Diadiploceras, Hyatt. Devonian. Tainoceras, Hyatt. Carboniferous.

Family 19. Centroceratidae.

Gyroceracones and nautilicones with young similar to early stages of Temnocheilus
before the impressed zone is formed. Shell subsequently becoming tetragonal in section,

SI-H-ORDERD ORTHOCHOANITES 526

the venter flattened or concave, mnl //-,/-.</'/,/ /••///»///////// eonvest /'/</// </ /"'
\,int/l/<;iiii'x have a persistent convex '••////•"// "/••" /'// ///•• /////»/•• .<.>../ rone, A'-/ " ////<//</ /•
kiii > n- ,i,

Centroceras, Hyatt. Devonian M < 'arl>oniferous. Tetmyonoceras, Whiteaves.
Devonian.

Family 20. Pleuronautilidae.

.}/«/•<> or less (1i*-ni<liil nnutilicones vitl, *t not, volutions ami /,/,-,/, umbilical perfor-
ations ; the young, especially in primitive species, remain in <i <-m •>'"•> /•<"•< /,/..-,- »////// ,/ /•//.•
sto(/«. More specialised shells are costated and tuberculated on tin- *!•!'.<. futures have
annular lobes except in Pselioceras. Siphuncle ventncl »f centra in tl« //.,/<
becoming dorsad in later stages.

PeeKoceras, Hyatt. Permian. Pleuronautilus, Mojs. ; A'//"'//oc/Trt«, gen. nov.
Type E. (Pleur.) superbus, Mojs. sp. ; Enoploceras, gen. nov. Type E. (Naut.) ll'ulf' m\
]\Iojs. sp. ; Anoploceras, gen. nov. Type A. (Pleur.) ampezzanus, Mojs. sp. Ti-ia>.

VII. KONINCKOCERATIDA.

Xnatilicones with biangular sections at an early stage of iimn-tli, ifi-ri'lnjiing ktter
into modified trapezoidal outlines as in many of. the Hercoceratida, but shells are .s-///"o/A,
and the. trapezoidal form as a rule evolves during the phylogeny into quadrangular, mnl
finally into involute coils with compressed sections, or may become simply more or less
trigonal through elevation of the venter. Annular lobes present in most genera.
Aperture constantly open, and in some forms remarkable lateral projections are
during the gerontic stage.

Family 21. Koninckoceratidae.

Shells of primitive forms similar to Temnocheilus, but leading into those
tetragonal sections, and finally into highly compressed volutions. All are smootli «nd
have marked umbilical saddles. Volutions with broad umbilical zones which become
lateral in the more involute species. Siphuncle ventrad of centre.

Koninckoceras, Domatoceras, Hyatt. Carboniferous. Potoceras, Hyatt. Devonian (1)..
Stenopoceras, Peripetoceras, Hyatt. Permian.

Family 22. Solenocheilidae.

Compressed elliptical in section during early stages, but full-grown of jiriiniffr,- /'.-/•//,.>•
mill i/nung of specialised derivatives have a more or less trigonal section in •/«•/'///»• stm/,-.
Later this stock evolves shells with volutions having depressed elliptical or brnm/lii li> mi-
spherical outlines. Sutures generally have large ventral middlf*, and saddles on the
umbilical shoulders. Umbilical zont ft ry l>r<i<xl, the increase by growth of flu </nr*iiin
being remarkably rapid. Shells smooth, <'mt <ij>erture in gerontic >•/»/»/»• mnii <l,,-,ln^
peculiar lateral projections, especially at the umbilical shoulders, v:Jii<-h are //.</!»///// very
prominent. Siphuncle sub-ventran.

Aipoceras, Oncodoceras, Hyatt; Asymptoceras, Ryckholt ; Solenocheilus, Mt-i-k.
Carboniferous. Pteronautilus, Meek. Permian.

Acanthonautilus, Foord. Nautilicones with sub - hemispherical volutions, the
dorsum flattened or concave. Aperture developing laterally into two projecting spines
at the umbilical shoulders. Carboniferoiis.

526

MOLLUSCA

SUB-KINGDOM VI

VIII. DlGONIOCERATIDA.

Primitive forms constantly retain depressed volutions having a more or less biangular
or sub-trigonal section ; specialised shells repeat these stages in the young, but subsequently
become more involute, and the sections change to reniform, sub-quadrangular, or sub-
elliptical. Shells smooth except in the single genus Cymatoceras. Aperture simple and
open at all stages ; gerontic living chamber only slightly contracted.

Family 23. Estonioceratidae.

Gyroceracones and discoidal nautilicones having slightly depressed, broad, rapidly
increasing biangular sections in the young, but becoming depressed oval or depressed
sub-trigonal in later stages. Siphuncle variable in position.

Estonioceras, Noetl. Ordovician. Edaphoceras, Remeleoceras, Lophoceras, Hyatt ;
Diodoceras, gen. nov. Type D. (End.} avonensis, Dawson sp. Carboniferous. Digonio*
ceras, Hyatt. Jura.

Family 24. Nautilidae.

Nautilicones with more or less involved volutions, the siphuncle slightly nummuloidal
and variable in position, but never near either dorsum or venter except in the young,
when it is frequently either near the dorsum or centren. Biangular stage much
abbreviated or absent, the trigonal stage present in most shells for a more or less pro-
longed period, but developing invariably by spreading of.
the venter into tetragonal, reniform, or hemispherical
outlines. Never decidedly discoidal, although umbilicus

FIG. 1073.

Nautilus pompilius, Linn.
Recent. Protoconch showing
linear cicatrix at apical end (after
Hyatt).

volution of N. pompilius,
sectioned longitudinally.
s, Siphuncle; c, Blind
origin of caecum; x, Empty
space or umbilical perfora-
tion (after Branco).

FIG. 1075.

Nautilus intermedius, Sowb. Middle
Lias ; Hinterweiler, Wiirtemberg.

is often open. More specialised forms have a minute umbilicus, and in some cases it is
completely hidden during the ephebic stage, although invariably open in the young.
Zone of impression present on the dorsum before jhe whorls are in contact. Annular
lobes often developed at an early stage, but liable to disappear in the adult ; absent in
some Tertiary species.

Cenoceras, Hyatt. Jura. Cymatoceras, Hyatt. Cretaceous. Eutrephoceras, Hyatt.
Cretaceous and Tertiary.

Nautilus, Linn. (Figs. 1073-1076). The young resembling adults of Digonio-
ceras until a late stage, and adults of primitive species (like N. umbilicatus] similar to

SUB-OKI >K K K OYBTOCHOANITES 5t7

ma. Sutures slightly inllertr.l, with taint ventral lol «-.- ; annular ]•.!..- pres.-nt.
\'< ilut ions sub-globose, a n< 1 umbilical perforation comparatively large.
Sijiliuncle centren in the apical camera, but later becoming v«-nlra«l
of centre. Tertiary (?) to Recent.

Sub-Order E. CYRTOCHOANITES. Hyatt.

Shells varying from orthoceracones to nautilicones, none of them
liinlilij ornamented, although some are annulated or costated, am/ in
rare cases slightly nodose. Sutures as a rule simpler than in Ortho-
choanites. Siphuncle varies exceedingly, passing from tubular in the
young and even in the full-grown of primitive forms to highly nummu-
loidal in the adults of specialised genera, or again in some groups
nfn/niiKi constantly its primitive character. The funnels, however,
are as a rule bent outward or crumpled, and generally short.

FIG. lOTO.

T A wr-TfvsTTmnxrATA Nautilus '••

1. A^LLOSIPHONATA. Titlioni.-m :

Stramberg, Moravia.

Mostly orthoceracones and cyrtoceracones, with a few gyroceracones

and very rarely nautilicones, the last-named being invariably discoidal. Apertures
constantly open. Siphuncle may be empty, but organic deposits when present always
gathered about or encrusting the funnels as hollow or solid internal rings. Deposits
sometimes sufficient to form more or less annulated endosiphuncles, the rings being opposite
the camerae, alternating with the septa, and extending outwardly.

Family 1. Loxoceratidae.

Smooth orthoceracones and cyrtoceracones similar to Orthoceratidae, but siphunch
distinctly nummuloidal, and funnels very short and crumpled. Deposits not uncommon,
but irregular, and only irregular endosiphuncles occasionally formed.

Loxoceras, M'Coy (Sactoceras, Hyatt). Mostly orthoceracones, circular or elliptical
in section. Siphuncle supposed to be tubular in the y<nmg, but highly nummuloidal
in later stages, centren or near the centre. Septa invariably single, and camerae
empty. Ordovician to Carboniferous.

Campyloceras, M'Coy (Aploceras, Hyatt). Breviconic cyrtoceracmie-, or orthocera-
cones with smooth or finely ridged shells, circular or depressed elliptical in section.
Siphuncle centren or ventrad of centre. Carboniferous.

Family -2. Uranoceratidae.

Cyrtoceracones, gyroceracones, and nautilicones with stout volutions. Siphuncle in
primitive forms highly nummuloi<l«l, hut invariably empty ; in nautilicones it ////* /<»•
nummuloidal segments, and is uniformly ventrad of centre, but not near f/i> venter.
Sutures with ventral saddles, lateral lobes, and also dorsal saddles in primitive forms as
well as the young of all shells. !"</'//>/ and dorsal lobes arise subsequently in tin-
ontogeny of nautilicones.

Uranoceras, Hyatt. Stout, mdre or less breviconic cyrtoceracones, compressed
elliptical or sub-quadrangular in section. Sutures with broad ventral saddles, lateral
and dorsal lobes. Siphuncle large, nummuloidal, centren or ventrad of cent re.
Devonian and Carboniferous.

Gigantoceras, gen. nov. Gyroceracones similar to the preceding, but having longer
living chambers and more compressed volutions. Includes the largest known Nau-
tiloid shells. Type G. (Gyroc.) inelegans, Meek sp. Silurian.

528

MOLLtTSCA

SUB-KINGDOM VI

Family 3. Actinocaratidae.

Orthoceracones and cyrtoceracones with siphuncle more or less filled by rings of
organic deposits, and having an endosiphunde in the central axis. Camerae m,n/ i><>

empty or filled to various degrees with organic
deposits, even to the extent of solidifying the entire
shell previous to gerontic stage. Shells smooth or
annulated, but not longitudinally ridged, at least in
the later stages.

Actinoceras, Bronn. (Figs. 1077, 1078). Ortlm-
ceracones and cyrtocera-
conesof usually depress, v [
elliptical section, with
large, excessively num-
muloidal siphuncle.
Funnels very short and
crumpled, sheath almost
globular. Internal de-
posits contracting the
central axis into an

Artlnocems vertebratum, Hall.
Actinoceras cochleatum, Schloth. Silurian ; Lockport, New York, annulated eiKlOSlphimcle
Silurian; Gottland. Abraded fragment Longitudinal section showing witTi fnl-mli v-i/Iio+ii-.
showing single septa and thick, annulated organic deposits of siphuncle
endosiphuncle. 1/2- (after Barrande). . from the annuli. Septa

often double, with an

interspace between the two layers near the siphuncle, but solid near the shell.

Ordovician to Carbon-
iferous.

Sub-genera : Ormocerux,
Stokes (Fig. 1079). Ordo-
vician to Carboniferous.
Paractinoceras, sub - gen.
nov. (Fig. 1080). Shells
longer and more slender

FIG. 1079.

Actinoceras (Ormoceras) Bayfieldi,
Stokes. Ordovician ; Lake Huron,
Canada. Longitudinal section showing
organic deposits of siphuncle partly
dissolved away (after Stokes).

FIG.' 1080.

Actinoceras (Paractinoceras)
docens, Barr. sp. Silurian
(E) ; Dvoretz, Bohemia. Ver-
tical section showing senile
stage without organic de-
posits, preceded by adult
stage with siphuncular
rosettes (after Barraude).

FIG. 1081.

Huronia vertebralis,
stokes. Ordovician ; Isle
Drnnimond, Lake Huron.

Siphuncle.

than in the preceding, with large siphuncular segments confined to early stages, and
very long living chamber. Type P. (Sact.) canadense, Whiteaves sp. Silurian.

Cyrtactinoceras, gen. nov. Type C. (Cyrt.) rebelle, Barr. sp. Deiroceras, Hyatt ;
Huronia, Stokes (Fig. 1081) ; Discosorus, Gonioceras, Hall. Silurian.

SUB-ORDER E CYRTOCHOAN1TES :. -»

(!) Tretoceras, Salter. Orthoceracones having a n-ntivn nummiiloidal
similar to that of Actinocera* but smaller, and with a >njn-rtii-.ial tubular .-i|.liiiin-|,-
(so-called), having very long but not Holochoanoidal funnels. Sheath not yet
to be present. It is possible that the struct un- ivirrn-d to is a peripheral
siplmucle formed by abnormal condition of tin- septa. Silurian.

II. ACTINOSIPHONATA.

Orthoceracones, cyrtoceracones, gyroceraconcs, and a few discoidal //,</, //.//Y/'/v*//. §. ,s'//« II*
fret//" ntly breviconic, in which case gerontic living chambers and apertures an wor<
highly contracted flnm in nil other Nautiloids. Siphuncle sometimes empty; organic
deposits when present in the form of laminae radiating from the sheath of each segment
towards the interior. These internal calcareous septa are united only in their peripheral
parts, not meeting at the central axis so far as known, and also liable to be more or less
interrupted in the transverse plane of each funnel. The interior is consequently an
actiniform en<l»*ii>h uncle with rays extending outwardly between the laminae of the
deposit*.

Family 4. Jovellanidae.

Orthoceracones and cyrtoceracones with slightly compressed oval, or depressed and
more or less sub-trigonal sections. Shells smooth or partially annulated. Siphuncle large,
with well-developed actiniform lamellae, and distinct endosiphuncles. Aperture open and
living chamber uncontracted in gerontic stage.

Includes Jovellania, Bayle ; 2Jripleuroceroceras, Hyatt. Silurian and Devonian.
Mixosiphonoceras, gen. nov. Type M. (Cyrt.) desolatum, Barr. Silurian and Devonian.
Projovellania, gen. nov. Type P. (Cyrt.) athleta, Barr. Silurian.

Family 5. Rizoceratidae.

Orthoceracones and cyrtoceracones expanding regularly by growth throughout life, the
living chamber very slightly or not sensibly contracted in gerontic stage. Aperture con-
stantly open, and with slight dorsal as well as somewhat deeper and
broader hyponomic sinuses. Siphuncle generally small and empty,
but actiniform lamellae and an endosiphuncle sometimes occur. Shells
as a rule smooth or with transverse bands only, but longitudinal
striae often present in earlier stages.

'Rizoceras, Hyatt (Fig. 1082). Orthoceracones and exo- or endo-
gastric cyrtoceracones having circular or elliptical sections. Living
chamber extraordinarily large and long as compared with camerated
part. Silurian to Carboniferous.

Cyrtorizoceras, gen. nov. Sections more compressed than in
Rizoceras, living chamber shorter and apt to be more or less
laterally compressed in gerontic stage, but the dorso - ventral
diameters only very slightly so or not at all. Sutures more sinuous,
and with decided ventral and dorsal saddles. Type C. (Cyrt.)
minneapolis, Clarke sp. Ordovician and Silurian.

r 10. 1082.
Rizoceras

Family 6. Ooceratidae. SSwSt S

Aperture open.
Orthoceracones and gyroceracones with closely set septa and large

nummuloidal siphuncle in later stages of the ontogeny, but tubular in tl<>
Actiniform deposits oftener present than in Rizoceratidae, but not general. Funnels very
variable, sometimes minutely plicated or hook -like in section, confined to dorsal side of
VOL. I 2 M

530

MOLLtJSCA

SUB-KINGDOM VI

FIG. 1083.

Ooceras (Cyrt.) Baylei,
Barr. sp. Silurian (E);
Lochkow, Bohemia
(after Barrande).

tube, or sometimes absent altogether. Living chamber short and like that of Cyrtorizo-
ceras; aperture not infrequently sub-trigonal in outline, but always
open.

Ooceras, Hyatt (Oonoceras, Hyatt), (Fig. 1083). Cyrtoceracones
more elongated and usually more compressed than in Cyrtorizoceras,
but otherwise similar except in structure of siphuncle. Septa
rise rapidly on ventral side, and may bend sharply orad, forming
a funnel ridge or shoulder on that side, but disappearing on. the
opposite side of the same funnel. When the funnel itself is
absent, the ridges look like reversed funnels or collars. Silurian.

Cyrtoceras, Goldf. Large exogastric, breviconic cyrtoceracones ;
sections depressed elliptical or approximating to trigonal, the
dorsum more or less flat, and venter elevated. Aperture con-
tracted in gerontic stage to a T-shaped opening, and placed at an
acute angle with the central axis, so that the dorsal side is very
much shorter than the ventral. Siphuncle large, nummuloidal,
with well -developed actiniform lamellae, and with an endo-
siphuncle in later stages of ontogeny. Devonian.

Family 7. Oncoceratidae.

A phylogerontic group of breviconic orthoceracones and cyrtoceracones similar to
Cyrtorizoceras, but shells much shorter and living chamber usually contracted, especially
in their transverse -diameters during gerontic stage. Siphuncle tubular or highly
nummuloidal, without deposits.

Eremoceras, gen. nov. Cyrtoceracones similar to Cyrtorizoceras, but living chambers
longer, and aperture more or less flaring and open. Siphuncle more or less nummu-
loidal. Type E. (Cyrt.) syphax, Bill. sp. Ordovician.

Cyclostomiceras, gen. nov. Slender, short, exogastric orthoceracones and cyrtocera-
cones, circular or compressed in section. Living chamber as compared with camera ted
part longer and larger than in most forms, less contracted, and with open aperture in
gerontic stage. Type C. (Pot.) cassinense, Whitf. sp. Ordovician to Devonian.

Oncoceras, Hall. Compressed exogastric cyrtoceracones with sections like Cyrtori-
zoceras, but shells as a rule much shorter and smaller, and siphuncle more distinctly
nummuloidal. Living chamber also more flattened laterally, the aperture elongated
and often sub-trigonal, but typically open. Ordovician.

Sub-genus : Meloceras (Melonoceras), Hyatt. Similar to the last, but lateral edges
of gerontic aperture grow inwards, and form pear-shaped outlines. Silurian.

Family 8. Poterioceratidae.

Smooth, breviconic orthoceracones and cyrtoceracones having circular or depressed
elliptical sections. Gerontic aperture, except in primitive forms, is contracted and apt to
assume a sub-trigonal outline; it is laterally narrowed and approximates those of the
next family only in Streptoceras. Outlines of aperture entire ; sutures straight or only
slightly sinuous. Siphuncle in this and remaining families, so far as known, slightly
nummuloidal and empty in the young, but becomes larger ; in specialised forms it is apt
to be more or less filled with radiating lamellae, and in late stages has an endosiphuncle.

Clinoceras, Mascke. Ordovician to Devonian. Sycoceras, Pictet. Devonian.

Poterioceras, M'Coy (Apioceras, Fischer ; Acleistoceras, Hyatt). Orthoceracones and
exogastric cyrtoceracones, short and stout, with sub-trigonal gerontic aperture. Brachial
area not decidedly differentiated from the hyponomic sinus, and contraction may take
place in all diameters or more extensively in the lateral. Ordovician to Carboniferous.

sri!-oKi>KK

CVKTOCHOAMTKS

Mill. Like tin- la-t l.tit more ;iivn;iti-, with laterally <-oui r.t,-t.-.|
aperture. .UK! a short hyponomir sinus distiiirt tViiiu tin- I'l-arhial area. Silurian.

Family 1). Trimeroceratidae.

Smooth breviconic orthoceracones and cyrtoceracones *//////»//• i<> /'.,/-//-.-.,
«n<l nut H /•>'*, but more slender, e*j>«-/<i!li/ in tin ////»/////, <m<l <//«/•/<'/•- »-./•;/ ili.<ti,,,-t in
primitive forms. Even the lntt>-r nxnullii Inn;- linn-ln'iil r//.--/ ////•//// ///<//•/.•«/ '///" /row
hyponomic area by ingrowth of sides of the aperture, and in all spec /-/ //.-,,/ ../,,//.< ///<
hyponomic sinus and s}n<-inl i njlfctions known as " l>,-in-lii<il sinuses" an f<> /•///"/ /'^ /»'>•<.<
o/ <Ae arms o?i etfo/es o/ brachial area. /-V//^////, Mr HJH rtun' hmmns /•,<///<•,</ /,, ,, /,/,,/•-
or iess F- o?' T-shaped fujnn\ n-ith. an open st>mi<-; r<-nl<i ,• >•/'// ;/x /// //*»• -,,,/ o/' ///- hyponomic
slit or area, and similar sinuses in the edges of tin In-m-lu'iil .<///. «•»»/• /v-xy/o//'////// /•/ //<>:
number of arms. All Silurian.

Mandaloceras, Hyatt (Dimorion, Ban-.), (Fi^. 1084). Dill«-rs JVum Potariocerat in
the gerontic aperture, which is laterally c<>nn-art<-<l, and lias h\ -jMinnmii- and l>ra<-lnal
areas distinctly dift'ereiitiated in all Imt the nn»>l j»riiniti\f
species. More specialised forms have, llicsc an-a.- narrn\\t-<l
down, but special sinuses are not formed.

FIG. 1084.

Min<ilii!<ii-i'rti.-<(<;<iiiij>li.) l:<ili> niii-inii, JJarr. sp. Silurian (EtageE);
Dvoretz, Bohemia. ^4, Side view of conch. J5, Aperture.

. 1085.

sji. Silurian (E) ; Dvoretz,

Holieniia. '/i (afti-r Hairaii'li-).

Trimeroceras, Hyatt (Trimorion, Trimeres, Barr.) ; Pentameroceras ; Septameroceras,
Hyatt. Silurian. Aperture in the lii-st has a median and two ln-arhial ; in tin-
second .a median and four l>ra<-hial ; and in the last a median and six l>rarhiul
sinuses.

Hemiphragmoceras, i^en. nov. ( 'oni]ire»ed endo^aMrie ''vrtoceracones having a
narrowed hyponomic area like Phragmoceras, luit with brachial aivas as in Dimeroceras.
Type H. (Phrag.) pusillum, Barr. sp.

Tetrameroceras, Hyatt (Tetramorion, Tetrameres, Barr.), (Fig. 1085). Like the la.-t,
but with more highly conti-artt-d ajieriun- and tour lateral sinuses.

Hexameroceras, Hyatt. Bracliial area with >i\ lateral sinuses. Octamci'
nov. Brachial area with eight lateral sinuses. Type 0. (Phragm.) ctiUiatonin. \\.\\\\ >p.

Kamily 10. Phragmoceratidae.

Smooth breviconic cyrtoceracones and gyroceracones rapid! // ,.< i>« mUmi /•// (ir»n-Hi in
their dor so-ventral diameters, and Imrinn <•/» n iipi-rim;:-: ,,/</»/ in y//-///*/V/Vr ///y/-x »./• tin-
young and ephebic stages of more specialised forms. In tin- (<itf>r <j< r<niti<- « i>< rfures are
laterally contracted and have a very l>mj lu/ponomic area terminated b;i <( lury
hyponomic sinus. The brachial area may be more or less open and elliptical) or

532

MOLLI/SCA

HUB-KINGDOM VI

narrowed and transversely elongated, but always has an entire outline. Siphuncle
generally large, nummuloidal, and often has actiniform
lamellae and endosiphundes in later stages. Shells mostly
endoyastric.

Codoceras, gen. nov. Excessively short and rapidly
expanding cyrtoceracoiies like some species of Rizoceras,
but with large living chambers, narrow venter, and large
siph uncle just ventrad of centre. Aperture constantly open.
Type 0. (Gyrt.} indomitum, Barr. sp. Silurian.

Protophragmoceras, gen. nov. (Fig. 1086). Similar to
the last, but form more compressed, and siphuncle near the
venter (internal). Differs from Phragmoceras in having
aperture open throughout life. Type P. (Cyrt.) Murchisoni,
Barr. sp. Silurian.

Gomphoceras, Sowb. Stout short orthoceracones and
cyrtoceracones similar to some species of Phragmoceras, but
straighter, stouter, and less compressed in form, and geroiitic

aperture less contracted laterally. Hyponomic sinus shorter,

T , • r\ f • • i n-i •

a curvature exogastric. Ordoviciaii and Silurian.

Phragmoceras, Sowb. (Figs. 1087, 1088). Compressed'
endogastric cyrtoceracones and gyroceracones, oval in section, and venter narrowly

FIG. 1086.

Protophragmoceras Murchisoni,
Ban. sp. Silurian (E); Loch-
kow, Bohemia. 1/2- '

FIG. 1087.

Phragmoceras Broderipi, Barr. Silurian (Etage E) ; Lockhow, Bohemia.
!/2 (after Barrande).

Phragmoceras Loveni,
Barr. Silurian (E) ; Loch-
kow, Bohemia. Section
showing lamellar organic
deposits (after Barrande).

rounded. Siphuncle large and near the venter (internal). Gerontic aperture much
contracted laterally, the hyponomic area very long and narrow. Silurian.

Incertae Sedis.

Nothoceras, Barr. Represented by the single species N. bohemicum, Barrande, in
which the septum turns orad, forming an inverted funnel. This funnel connects with

I

RANGE AND DISTRIBUTION OF TIIK XAUTIUUDKA :.:i:i

a more or le>s inflated >heath tliat do.-ed tin- -iphunclr, ;ilnl connected it with the

distal opening of the next succeeding M-ptum, thus completely re\er.-ing the relative
po-itions of funnels and sheaths in other forms. The appearance- &fl de-crjbed by
Barrande are not deemed Hillicieiit to prove tin- truth of tlii.- .-tatement, and it iv
unsafe to accept it absolutely until the development has Keen >iudied. The cavity i-
divided by radiating lamellae running longitudinally a.- in the

Range and Distribution of the Nautiloidea.

Fossil Nautiloidea have been recorded by Millings as occuri -ing in Canada earlier
tlian the Quebec Group, but his statement lacks confirmation An abundant GVphalo-

podan fauna makes its appearance in the earliest Quebec or ( 'alciferou.-, and i- quite
distinct from other later a. -semi >1 ages. Diphragmoceras and other orthocera<-one- and
cyrtoceracones with very peculiar si pliancies occur here, but gyroceracones and nautili-
cones are absent. However, the information we have at piv-ent of tlii- fauna i.-
limited, and but few positive conclusions can be drawn.

All the sub-orders of Nautiloidea are initiated in the Ordovician, and one of them,
Schistochoanites, is confined to this period. Holochoanites and Mixochoanite* become
extinct in the Silurian, and only Orthochoanites survive the Palaeozoic. The sub-
01 ders that disappear at this early date are remarkable for their complicated siphun-
cular structure, and peculiar sigmoidal septa observed in the gerontic living chanibei>
of certain forms (Ascoceras, Gonioceras), while their prevailing habit is gyroceraconic.
The sigmoidal septa do not become complicated in correlation with closer coiling of the
shell, but occur in cyrtoceracones correlating with highly compressed cones, and in
orthoceracones correlating with strongly depressed cones.

The older classifications recognised the straight orthoceracones, curved cyrtocera-
cones, loosely coiled gyroceracones, and more closely coiled nautilicones as distinct
natural divisions. Although it is possible to employ the habit of curvature in con-
junction with family groups as a convenient means for tracing laws of distribution and
the like, yet for more accurate data the genera must be considered independently.
For instance, some families made up largely of gyroceracones and nautilicones al-o
contain a few orthoceracones and cyrtoceracones, and these have to be neglected in
estimating the relative proportions of straight and coiled conchs. Other sonr>.~ o|
error are presented by sporadic uncoiled or gerontic forms which occur in I'amilie-
having coiled shells. In a general way, however, it is possible to state the morphic
succession as follows : —

Orthoceracones, together with their almost invariably associated cyrtoceracones
exceed gyroceracones in the Quebec in the proportion of three families to one, and this
horizon contains but one family of closely coiled nautilicones, and one of the um oiled
or gerontic type. In the Ordovician are. found no less than fourteen families having
straight or approximately straight >hells, as against seven families of gyroceracones and
nautilicones. Thereafter until toward t he close of the Palaeozoic, the proportions of
straight and coiled forms remain ippro.ximalely equal. The Permian has but one
surviving family of orthoceracones, and four of the coiled groups; in the Trias tin-
ratio is one to six, and in the Jura coiled forms alone persist. Thus, a slowly working
tendency is apparent, leading to the production of more and more closely coiled cones,
and the elimination of straight and slightly curvet] forms. Gyroceracones disappear
with the Carboniferous, and the more discoidal nautilicones with the Trias.

Some curious features are presented by the phylogerontic or uncoiled shells. Only
one family, the Silurian Lituitidae, have all the genera uncoiled save the probab],-
ancestral close-coiled type. Other families nave isolated genera or species exhibiting
similar tendencies, and becoming partially uncoiled during their later stages, although
close-coiled in the young. Such forms occur throughout the Devonian, but none have

534 MOLLUSC A

SUB-KINGDOM VI

yet been found in the Carboniferous, where uncoiling of the volutions, when it
occurred, took place earlier than the gerontic stage. From the Mesozoic and later
horizons, no species is known in which the gerontic stage is to the slightest degree
uncoiled.

Torticones are more aberrant than any other conchs, and may be best classified as
phylogerontic forms, since tendencies toward unsymmetrical development of the
volutions occur in the gerontic stage, and are genetic in but a few genera, where they
appear during the early stages and are preceded so far as known by a symmetrical
volution. The first manifestation of torticones is in the Ordovician, and their acme is
attained during the Silurian. As regards ornamentation, annulated shells appear in
the Calciferous, and those with longitudinal ridges later in the Ordovician, together
with tuberculated and costated gyroceracones and iiautilicones. The last-named, how-
ever, are much more abundant in the Devonian and Carboniferous, after which they
disappear. Very highly ornamented shells exist in the Trias, but following this
period the conchs are smooth.

Very striking is the marvellously sudden rise of the Nautiloidea as a group,
reaching its maximum in the Silurian, and followed by a decline extending from the
Devonian to the Trias. Then the forces acting unfavourably upon their existence
were arrested, or their violence lessened, and the group has been affected by only very
slight changes and an exceedingly slow process of retrogression until the present time.
The acme of siphuncular differentiation occurred in the Ordovician, of general morphic
diversity in the Silurian, of ornamentation in the Devonian, and of sutures in the
Trias.

Geographically considered, some facts of distribution are of general interest. The
fauna of the Quebec or Calciferous, which in Newfoundland, Canada, Vermont, and
the vicinity of Poughkeepsie, New York, is rich in fossil remains, is represented by
but a few camerated conchs in the Durness Limestone of Scotland. Holochoanites and
Schistochoanites are most plentifully represented in the American faunas, but Mixo-
choanites very sparsely so, at least as compared with the Ordovician and Silurian of
Bohemia. The same is true of the Lituitidae, Ophidioceratidae, and Hercoceratidae
among Orthochoanites, and of the Jovellanidae, Trimeroceratidae, and kindred families
among the Cyrtochoanites. The Devonian and Carboniferous faunas of America and
Europe are nearly on a par, but the Permian and Trias of the western hemisphere are
very deficient in Nautiloid remains. The Jurassic faunas of America have so far
yielded but one specimen of a Nautiloid, but they were probably present to some
extent, since they are represented in the Cretaceous of this country. During the
Cretaceous and Tertiary the principal distribution of the Nautilidae was in the
eastern hemisphere, and the last surviving species of Nautilus are now restricted to
oriental waters. The accompanying table shows the range of the leading Nautiloid
families.

[The Hercoceratidae occur in the Devonian, and not in the Silurian rocks, as is stated
through an oversight on page 524.]

VERTICAL RANGE OF THE NAUTILOIJHIA
TABLE SHOWING VERTICAL RANGE OF THE NAUTILOI I >l. A.

Families.

.2

.--

1

i
*

•11V!'

Carboniferous. 1

I

,

\

1

„•

I

I. HOLOCIIOANITKS

1. Diphraginidae .
2. Endoceratidac .
3. Cyrtendoceratidac .

II. MlXOCHOANlTI s

1. Ascoceratidae .
•J. Mesoceratidae .

III. SCHISTOCHoAM I I :>

IV. ORTHOCHOANM i ^
1. Orthoceratidae .

—

2. Cycloceratidae .
3. Kionoceratidae .
4. Tarphyceratidae

5. Trocholitidae .
6. Plectoceratidae
7. Ophidioceratidae
8. Lituitidae
9. Grypoceratidae
10. Clydonautilidae

—

11. Halloceratidae .
12. Ryticeratidae .
13. Rhadinoceratidae

—

14. Tiigonoceratidae

15. Triboloceratidae
16. Rhineceratidae
17. Hercoceratidac .
18. Tainoceratidae .

^^_

19. Centroceratidae

20. Pleuronautilidae
21. Koninckoceratidae .

22. Solenocheilidae
23. Estonioceratidae
24. Nautilidae

MMHHM

^— —

V. CYRTOCHOANITKS
1. Loxoceratidae .
2. Uranoccratidae
3. Actinoceratidae
4. Jovellanidac

—

' 5. Rizoceratidae .

6. Ooceratidae

7. Oneoceratidae .
8. Poterioceratidae
9. Trimeroceratidae
10. Phragmoceratidae .

_^

=

......

536 MOLLUSCA SUB-KINGDOM vi

Order 2. AMMONOIDEA.1

Shells similar to those of Nautiloidea in some primitive Palaeozoic groups, but
these give rise to others with more highly ornamented shells, the apertures of which
have ventral rostra instead of liyponomic sinuses. Sutures, as a rule, have ventral
lobes in the later stages of ontogeny ; the inflections become more numerous than in
Nautiloids even in Palaeozoic .genera, and their outlines during the Mesozoic are
extremely complex. Siphuncle invariably small, and (except in Gastrocampyli)
situated near the venter. Funnels short, monochoanitic in primitive forms, but
becoming diplochoanitic during the Palaeozoic, and as a rule, chloiochoanitic during
the Mesozoic.

The ontogeny begins with a calcareous protoconch, the apical stage of the
conch being an open neck built in continuation of the permanent aperture of
the protoconch. The first septum is concave as in Nautiloids, and sutures are
straight or have more or less of a saddle on the venter. Young stages of
Mesozoic shells recapitulate the primitive characters of Palaeozoic forms. The
aperture was closed when the animal was retracted by a single horny plate
(anaptychus) or pair of calcareous plates (aptychus), probably secreted by
muscular lobes homologous with the hood in Nautilus.

Shell Characters. — There are apparently no characters, not even the presence
of a calcareous protoconch, which can be relied upon to separate Bactrites from
the orthoceraconic Nautiloids. Nevertheless, the position of the siphuncle and
its peculiar funnels are features which seem to place this form with true
Palaeozoic Ammonoids. There is but one series of straight shells among
Ammonoids, and these are obviously not the same as orthoceracones, but are
more properly called badriticones (Fig. 1120). Similarly, the loosely coiled
Mimoceras shells (Fig. 1121) are not gyroceracones, but only their morphic
equivalents in a different genetic stock ; hence the term mimoceracone should
be substituted for gyroceracone. In the same sense the closely coiled sym-
metrical shells, comparable in external aspect and intimate structure with
nautilicones, should be described among Ammonoids as ammoniticones. The
term torticone, however, can be conveniently applied to both groups, since it
does not connote any special structures, but is a general name for all asym-
metrical spirals.

Ammoniticones in many Palaeozoic forms are mimoceracones during
nepionic stages, and consequently in later stages a perforation is present
passing through the umbilicus as in Nautiloids. However, in most Carboni-
ferous and all later ammoniticones, the coiling is so close even at the beginning
of the conch, that the protoconch is closely enwrapped by the first volution,

1 Besides the works cited on pp. 502-505, the following may be profitably consulted -.—Buckman,
•V. &, Divisions of so-called Jurassic Time (Quar. Journ. Geol. Soc., LIV.), 1898.— Clarke, J. M., The
Naples Fauna (16th Ann. Rep. N.Y. State Geologist), 1898.— Crick, G. C., Muscular Attachment of the
Animal to its Shell in Ammonoidea (Trans. Linn. Soc. [2], VII.), 1898. — Diener, C., Cephalopoda of
the Muschelkalk (Mem. Geol. Survey India, ser. XV., Himalaya Fossils, II.), 1895.—ffavg, E.,
Etudes sur les Goniatites (Mem. Soc. Geol. France, Paleont, VII.), 1898.— Levi, G., Fossili degli
strati a Terebratula aspasia (Boll. Soc. Geol. Italia, XV.), 1895.— Parana, C. F., and Bonarelli, (?.,
Faune du Callovien inferieur (Chanazien) de Savoie (Mem. Acad. Savoie, VI.), 1897. — Semeno/, B.,
Anwendung der statistischen Methode zum Studium der Vertheiluug der Ammoniten (Ann. Geol.
Mineral. Russie, II.), 1&97.— Smith, J. P., Development of Lytoceras and Phylloceras (Proc. Calif.
Acad. Sci. [3], I.), 1898. — Cho/at, P., Les Ammonees du Bellasien, des Conches a Neolobites Vibra-
yeanus, du Turonien et du Senonien. Faune cret. du Portugal, vol. I. ser. II., 1898. — Jackson, R. T.,
Localised Stages of Development in Plants and Animals (Mem. Boston Soc. Nat. Hist. V.), 1899.

ORDER II

AMMONOIDKA

587

;iiid no perforation is visible even under a magnifier. There are two pit.-,
however, one on either side of the apical end of the conch, which remain as
remnants of this perforation, and are present in all ammoniticones (except
perhaps certain Gastrocampyli}. The bactriticone obviously represents the
primitive or primary radical of the Ammun«i<l«t. and the niimnrrrarone the
next or secondary radical of this order.

Ammoniticones of the J//V/v«w //,////// introduce a peculiar form of volut inn.
the anarcestean (Fig. 1122), which is depressed and crescentic in section, and
may be regarded as the Tertiary radical. These forms evolve a series becoming
more involute and compressed (Fig. 1123), and some with elevated or narrow
venters and well-defined lateral zones (Fig. 1124), but still retaining in the
young more or less of the anarcestean aspect. The Gastrocampyli have a few-
radical forms of similar aspect and with somewhat similar sutures (Fig. 1116) ;
they then produce a series of compressed discoidal shells having cordifoi m or
quadrate sections (Figs. 1117-1119), and these also develop involute forms
among specialised species. The Mesocampyli and Glossocampyli have a similar
history, but in the Eurycampyli coronate or gastrioceran forms (representing a
quaternary radical) with trapezoidal section and broad venter become common
in the ephebic stages (Fig. 1132). The primitive radical forms of the
anarcestean ammoniticones are replaced among the Phyllocampyli by the
smooth, discoidal, compressed quinary radical, or prolecanitean type (Fig. 1155).
This appears among the adult Gastrocampyli, although with distinct sutures,
and is also found among the Discocampyli. In the more specialised sub-orders,
the anarcestean type reappears only during the young stages. These last two

FIG. 1080.

Asellate protoconch of Gephyroceras calculi-
forme, Beyr. sp. Upper Devonian ; Biidesheim,
Eifel. A, Viewed from in front. Ji, From the
side (after Branco).

Bio. 1090.

Latisellate stage of Arcestes cymbiformis, Wulfen sp.
Trias ; Aussee, Austria. A, Viewed from in front.
/;, From the side (after Branco).

radicals persist into the Jura and Cretaceous, but exhibit more complex sutures
and other progressive structural changes in their ephebic stages.

Phylogerontic series (Ehabdoceras, Cochloceras) make their appearance in the
Upper Trias, become more abundant in the Jura, and still more important
during the Cretaceous. They have their own peculiar radicals, sometimes
found among discoidal and again among more involute shells, but for the
most part they do not originate from smooth shells.

The same descriptive terms are used for shell characters among Ammonoids
as among Nautiloids (see p. 512 et seq.). Obviously the first stage of the
conch was that of a living chamber, the protoconch being without internal
septa or siphuncle (Fig. 1101). Then, after building out the usually flattened
neck or apical part of the conch, the animal rested, and the first septum as
well as the caecum (or incipient stage of the siphuncle) was secreted. The first

538

MOLLUSCA

SUB-KINGDOM VI

FIG. 1091.

Angustisellate stage of Phylloceras hetero
phyllum, Sow. sp. Lias.

septum closed the aperture of the protoconch, and the caecum projected into
its interior. The caecum is connected with the internal surface of the proto-
conch by bands (Figs. 1101, 1102), or semiconical prolongations, described

by Munier-Chalmas as the prosiphon. But
these bands are of various shapes, are not
connected with the interior of the caecum,
and appear to be merely calcareous supports
for the bottom of the caecum. The earliest
sutures, described in a masterly way by
Branco, are divided by him into three classes :
asellate, latisellate, and angustisellate (Figs.
1089-1091). The first cross the venter as a
straight line or very slight saddle, and are
present only in the ephebic stages of Cyrtodymenia (?) and in the mimoceran
stage of the Microcampyli. In all except primitive forms it is confined (as are
most of the purely nautiloidean characters) to the first septum. The latisellate
stage is characterised by a decided broad saddle on the venter, with corre-
sponding deeper and broader lobes on the sides. The angustisellate stage has
prominent, sometimes almost sub-acute ventral saddles with corresponding deep
lateral lobes, accompanied by definite saddles at the umbilical depressions.

The last two stages are progressive modifications confined to the larvae of
Ammonoids, and are not present in the ephebic stages of any known species.
The asellate condition of the first septum is found in the ananepionic stage of
one species of the Gastrocampyli, according to Branco, but his figure shows a
saddle on the venter. The Microcampyli and Mesocampyli are asellate, and the
Eurycampyli also in A R c

some primitive De-
vonian genera, but
latisellate in others,
and angustisellate
in the Trias. The
embryos of primi-
tive Phyllocampyli
are unknown, but
the Triassic Lobi-
tidae and Arcestidae
are latisellate, while
the Cladiscitidae and

,i r>j 77 , . 7 Goldf. sp.). Carboniferous Limestone ; Choquier, Belgium. B, Same in a latisel-

tne JrliyliOCeraiiaae late Ammonite (Tropites siibbullatits, Hauer). C, Same in an angustisellate

nrp ano-n<5ri«pllatp Ammonite (all after Branco). Sutures of the first volution are lettered con-

6 secutively from g to I ; those of the second from m to s.

throughout. The

embryos of Discocampyli are almost unknown, but are supposed to be latisellate,
with the exception of the highly specialised Pinacoceratidae, which are angusti-
sellate. The remaining sub-orders are wholly Jurassic and Cretaceous, and so
far as known, the first septa are angustisellate.

Sutures.1 — The second septum (Fig. 1092) in all but the most primitive

1 [The nomenclature commonly in vogue designates the sutural inflections as follows : — The ventral
or external lobe is bounded on either side of the mesal plane by the large first or superior -lateral
saddle. This is followed by the first or superior-lateral lobe, and then come the second or inferior-
lateral saddle and lobe in the order named. All additional inflections occurring between the second

FIG. 1092.
Development of sutures in a latisellate Goniatite (Glyphioceras diadema,

OUDKK II

AMMONOIDKA

539

Pro.

Suturr-linr of Cyrto-
<•///;»•• /i i'« laevigata,

Munst.

L /•;/,

FlO. HI!'!.

*u\m-,' \\i«'<>tAnarce8tessubnaittiHnus, Schlotli.
I- \onian.

forms becomes divided by an entire azygous lobe on the \mt.-r, often
the "siphonal lobe," but herein after referred to as the /•/•////>///„/*•, and by
a smaller azygous lobe (shown to "the left in Fig. 1092, A-C) on the dorsum,
usually termed the
antisiphonal. This un-
divided ventral lobe
(Figs. 1094, 1095, EL)
persists throughout
the Microcampyli so
far as known, and is
obliterated by a secondary ventral saddle only in the Gastrocampyli. It is
present throughout the ontogeny of the simplest or radical forms of Eury-

campyli, Glosso-
campyli, and
Phyllocampyli. But
in the Devonian
L !':I- "'- <'11 l L EL Mesocampyli and

FIG. 1095. FIG. 1096. Triassic Disco-

Suture-line of Brancoceras sul- Left half of suture-line of Ceratites nodosus, . n..i • aV.«11a

<-»t,i*, Miinst. sp. Devonian. de Haan. Trias. ^ampyil,

having undivided

ventral lobes have not been recorded ; in the Tirolitidae but one such species has
been doubtfully described. This class of radicals is replaced in these sub-orders
by those having the ventral lobe
divided by a small saddle usually
called the ventral or siphonal
saddle (Fig. 1097, m). The class
of radicals having entire ventral
lobes disappears before the close
of the Trias.

The entire antisiphonal lobe
has a more extensive distribution
than the entire ventral lobe, being

Bight Bature-liH6 of Coroniceras bisttiaatum, Bru^,

, . Lias, m,

EL. V.-ntral (also

* u,;. ,,,,,,,,*.

ES, /..s1', /.N-, First, second, and third lateral sa-1- ll.-s.

. .1 i 4.1,

present throughout the Ontogeny ^ilt\ltniAl sa.i.ll.-; „, Line of involution.

of Microcampyli, Gastrocampyli, and jBg

Most Of the Ev/ni- lobe.

*.v» •! T. i.- u \ IS> D sae. ,, n

have thlS lobe entire, but lying on line of involution.

it becomes bifid in the later stages

of specialised forms. The radicals of Glossocampyli have it entire, but in
specialised genera it becomes bifid or even trifid. It is known to be entire
in only a few of the Lecanitidae, and is bifid in most of the Discocampyli and
Phyllocampyli^ besides having for the most part entire sides. It is also entire
in some phylogerontic species of the Trias. In the Leptocampi/li it is generally
bifid, but may be trifid or irregular in some species, and is accompanied by an
extraordinary growth of two of the branches inwards in a large number of
forms. In Jurassic and Cretaceous Ammonoids, it is as a rule more or less

lateral lobe and the line of involution are termed auxiliaries, and numbered in regular order. The
antisiphonal is also known as the internal, dorsal, or columdlar lobe. By " lobes " are always
understood the angulated or digitated portions of the suture which are directed backwards, away
from the mouth of the shell ; "saddles" are the elevations between them, which point towards the
aperture of the shell. — TRANS.]

540

MOLLUSCA

SUB-KINGDOM VI

complicated by the development of secondary inflections on the sides, termed
marginals.

Paired or zygous lobes and saddles (Fig. 1092) appear between the two
azygous lobes and belong to two series, the laterals or externals, and the
dorsals. The first broad external lateral inflections, called the " first pair of
lateral saddles," are formed by the ventral lobe and the corresponding first
pair of dorsals by the formation of the antisiphonal lobe ; and between these
there appears a broad lobe, either wholly or the most part external (Fig.
1092, A). This is the stage marked by four lobes and saddles — two azygous
and two zygous lobes, and four zygous saddles. The wide lateral lobes in the
next stage (Fig. 1092, Ck) are divided by saddles that arise on or near the lines
of involution. These divide the two lobes into four, one pair being in part or
wholly dorsal, and becoming eventually the first pair of dorsal lobes ; the
others develop into the " first pair of lateral lobes." There are accordingly
six lobes and six saddles at this stage. In the next stage (Fig. 1092, A, £m,
Cm) the saddles bridging the lines of involution become divided by lobes
arising on or near the lines of involution, and the inner arms of the saddle so
formed thus become the second dorsal saddle, while the outer form the second
lateral saddles; but in some forms they may both pass into the lateral series.
This stage, therefore, has eight lobes and eight saddles — three paired lobes
and four saddles on either side of the mesal plane, and two azygous lobes.

Additional inflections arise in like manner along or near the line of
involution during succeeding stages. But there is considerable irregularity in
their advent even in the eight-lobed stage, and still more so at later periods ;
hence the above description must be regarded as a very general one, although
serving to indicate a few primitive lobes and saddles that are generated during
the younger stages, and are usually recognisable in the adult.

In subsequent stages additional inflections arising on or near the lines of
involution pass outward as the sides of the shell broaden by growth ; and the

FIG. 1098.

Pinacoceras Metternichi, Hauer sp. Keuper ; Someraukogel, near Hallstadt, Austria. Left suture-line, much
reduced, showing auxiliary (inner) and adventitious (outer) inflections. The three longest lobes in the middle
are the first, second, and third laterals (after Hauer).

same law holds true for the dorsum, but of course here the inflections pass
inward toward the mesal plane. The number of inflections on the dorsum is
more limited in all forms than the laterals, and they have simpler outlines.
The inflections added to the sides after the first two or three saddles and lobes
appear are usually called the auxiliaries (Figs. 1096, aL 1098), but the current
use of this term is not consistent with the development of the inflections, and
the distinctions are based for the most part on the contrast in size between
the saddles and lobes as they appear in the adult of different types. When
the ontogeny is known, however, the auxiliary inflections can be properly

ORDER ii AMMONOIDEA ., I 1

discriminated ;iml described, but other\vi>»- are li;il»lc to confuse the nomen-
clature. Adventitious inflections (Fig. 1098) arise between tin- first pair
of laterals and the median line of the venter, either
by the growth of marginals in the arms of the ventral
lobe, or by division of the outer parts of the tir>t
lateral saddles, or by division of the inner parts of
the siphonal saddle.

The regions of greatest metabolism or growth-
changes in each genetic series are near the line- m
involution, and it is here that new inflections are
usually formed. The later formed lobes and saddles
in these regions repeat in their own development the
oritogenetic stages of modification through which the |.,,

older ones have already passed. It follows also from ivtoeerae tmtviatum, s,,wi,. sp.
this that the lobes and saddles nearest the umbilical 2^^*5*3!
lines of involution are simple and often entire, and ^be^ VIS ^rio'r u£»™i1PioS?
are parts of a series that become progressively more i, inferior lateral lobe ; ;>, K\-

T j A.I. v i r xi. ternal saddle; /

complicated outwards to the lines or columns ot the second lateral saddles,
oldest class — the first lateral lobes and saddles.

When there are adventitious lobes, this series is reversed on the ventral side
of the first pair of saddles. The inversion is sometimes quite complete, as
in some of the Glossocampyli, thus indicating unusual metabolism on the venter
like that of the regions of involution. Jackson's law of the localised re-
capitulation of ontogenetic stages is well exemplified by the history of sutures
among Ammonoids as already shown by him in Placenticeras.

The above method of designating the lobes and saddles as paired in the
external aspect and on the dorsum on either side of the mesal plane disregards,
for sake of convenience, an important fact that should be noted ; namely, that
the azygous ventral and dorsal lobes are in reality paired with each other in
the mesal plane ; also that the primitive dorsals and external lateral inflections
correspond in the same sense to one another, and are also more or less united
across the septa in some forms.

The outlines of the paired lobes and saddles first become complicated in
the Carboniferous Eurycampyli. Minor or marginal inflections are introduced,
and what are termed bifid or trifid lobes occur in the arms of the ventral
(Fig. 1156) lobe; they then affect the primitive first lateral lobes and saddles,
and extend thence toward the line of involution (Fig. 1159). These marginal
inflections increase greatly in number and complexity during the Permian,
become preponderant in the Trias, and universal in the Jura and Cretaceous.
During the Carboniferous it is the lobes only, as a rule, that are thus modified ;
but in the Permian the saddles too are generally affected. The modifications
in outline proceed from the lobes to their sides, and thence to the saddle bases,
except in certain cases when direct division of the saddles takes place by the
outgrowth of secondary median lobes that divide their bases. All these
secondary lobes and saddles are termed marginals.

Siphunde. — The caecal condition of the siphuncle is apparently confined to
the ananepionic stage or first septum, but J. P. Smith has shown that some
species of Lytoceras and Phylloceras have a bulbous enlargement of this organ,
which may persist in several nepionic camerae. This is apparently a persistent
remnant of the caecal enlargement. The siphuncle of all Ammonoids is larger

542

MOLLtlSCA

SUB-KINGDOM VI

in proportion to the volution, and apt to be nearer the centre (Figs. 1 100, 1101)
during the young than at later stages, and is also monochoanitic, as in Nauti-

FIG. 1100.

Tropites, cf. Phoebus, Dittm. Trias. En-
larged section in the median plane of the
young, showing monochoanitic funnels in
nepionic stage, then transitional, and later
chloiochoanitic funnels, a, Position of pro-
toconch (after Branco).

Paltopleuroceras spinatum, Brug. Lias.
Section parallel to median plane, show-
ing position of the siphuncle (after
Branco).

loids. It remains monochoanitic (having only a funnel) in the Gastrocampyli,
Microcampyli, and Mesocampyli, as well as primitive forms of Eurycampyli ; but
it becomes diplochoanitic (having both funnels and
forwardly directed collars) in more specialised Car-
boniferous Eurycampyli, and finally chloiochoanitic
(funnels lost, collars alone remaining) in Permian
genera. Most Triassic and all Jurassic and Cre-
taceous genera have the siphuncle chloiochoanitic.
The above stages are repeated in regular succession
during the ontogeny of chloiochoanitic forms (Fig.
1100) except when accelerated development (tachy-
genesis) occurs, and then the monochoanitic stage
may disappear. The reduction in size of the
siphuncle among Ammonoids is obviously corre-
lated with loss of functional importance, as is also
the case among more specialised Nautiloids ; and
gowb consequently organic deposits are not found in the
camerae of these shells.

Living Chamber. — This varies greatly in all of
its dimensions, thus indicating differences in the
size and proportions of the animal, since its body
parts were probably wholly contained within this cavity. The lines of growth
and the few apertures known among Microcampyli and Gastrocampyli show that
they had hyponomic sinuses on the venter, and were swimmers like Nautiloids.
The same was probably true of the Mesocampyli, except during the gerontic
stage of some species when a ventral crest arises, as demonstrated by Clarke.
In the Eurycampyli and Glossocampyli many species that retain the so-called
goniatitic form have hyponomic sinuses, but occasionally short ventral crests
appear, and later these become general. Only radical Palaeozoic forms of the

FIG. 1102.

Parkinsonia ParMnsoni,
Middle Jura. Median section show-
ing siphuncle with bulbous enlarge-

ent (c), prosiphon (p), and

sition

of protoconch («), (after Munier-
Chalm

Chalmas).

OHDKH II

AMMONOIDEA

543

Phyllocampyli have retained the hyponomic sinus ; short obtuse crests a pp«-ar
in the Trias, and continue thereafter. Jurassic and Cretaceous Ammonoidfl
have as a rule more pointed rostra than those of the Trias, and frequently
develop lateral crests and lappets (Figs. 1103-1107).

Very decided decrease in the dimensions of the, living chamber during tin-
senile stage does not occur as a rule among Palaeozoic forms ; but this con-
dition appears among the Triassic Haloriti</<" and Tm/iifii/iH' wit li a ronvspondmg
contraction of the aperture. The Arcestidae (Fig. 1164) and some species of
Discocampyli also often have very narrow openings during tin- paragerontic
sub-stage, but the condition is in no sense phylogerontic except in /,"/>//»,
and the like (Figs. 1160, 1161).

Pompeckj, in an important essay, asserts that contracted living chambers
are invariably developed in old age, and that small
shells possessing them are consequently not im-
mature individuals, but dwarfs (Fig. 1107). It is
probable that large numbers of shells are indeed
dwarfs, but it is also a fact that contraction of
the living chamber and volutions occurs in some
forms during comparatively early stages ; and
sometimes in such a way as to affect the ephebic
stages of the ontogeny, when the forms become
truly phylogerontic. This latter term is used to
designate shells in which the ontogeny has become
permanently modified by the assumption of retro-
gressive characters that were introduced first in
the senile stages of allied progressive species.
Whether these peculiar forms have contracted
apertures in their earlier stages, and then resorb
them before building further, or whether they
never add lateral lappets, rostra, etc., as claimed

by Pompeckj, until the last resting stage of the ontogeny (Fig. 1107), it is
obvious that they are permanently affected by phylogerontic characters.

F,0 1103

mpoioceras cristatum, Deim-. sp.
APerture with v"lillai

FIG. 1104.

Sphaeroceras Srong-
niort;, Sowb.sp. Oolite.
Aperture with broad,
contracted ventral ros-
trum.

1105.

\''iriiiiinii!ti's

•'.'. 1 1. sp. Oolite.
Aprrtuiv

lappete.

. .
with

Fio. 1106.
Glochicera*
batum, Opp. sp.

Jura,
lappets.

Lateral

Oecoptychius re-

•!'• H;i;Ui s]>.

.Jura. Living chamber

I'ontr.-ictfd, with m*-
tnmi and

These forms are comparatively rare in the Trias (Lobites, Cochloceras), but
their number is sensibly increased in the Jura, although usually confined
to special localities. During the Cretaceous they become more numerous and

544

MOLLUSCA

SUB-KINGDOM VI

FIG. 1108.

Oppelia steraspis, Opp. sp.
Upper Jura ; Solenhofen. Com-
pressed shell with aptychus (a)
preserved in living chamber and

more widely distributed (Figs. 1229-1231). In their extreme modifications
they become more or less uncoiled and finally perfectly straight.

Crick and Waagen maintain that Ammonoids had an annular band as well
as shell muscles, and that these served both to hold the animal in the living
chamber, and also formed an air-tight band around
the face of the mantle, fastening the latter to the shell
(Fig. 1108). Such was, however, probably not the
only means of attaching the animal to the shell. The
steady progressive complication of sutures, affecting
both lobes and saddles as well as their marginal in-
flections, is directly correlated with the outgrowth of
rostra. The presence of a rostrum indicates the
disuse and disappearance of the swimming organ
(hyponome), which in Nautilus causes the formation of
the hyponomic sinus in the aperture, and flexed
growth -lines on the venter. These facts and the
gregarious littoral habits of Ammonoids show that
they probably crawled along the bottom with their
shells carried above them, very rarely swimming.
Their shells are also less bulky in proportion than
those of Nautiloids, and correspondingly less buoyant.
All these observations justify the hypothesis that the progressive complication
of Ammonoid sutures took place because of their utility in
helping to carry and balance the shell above the extruded
parts when the animal was crawling. The greater com-
plication of the marginals in Jurassic
Ammonoids, where the number of auxiliary
lobes and saddles is often reduced (Fig.
1192), and the multiplication of the prin-
cipal inflections in Pseudoceratites of the
Cretaceous in compensation for the sup-
pression of marginals (Fig. 1224), are all
accounted for by this theory. The phylo-
geroritic forms, in which the lobes and
saddles are sometimes reduced in number,
and the marginals also less complex —
together with the position, form, and mode
of growth of the last volution, and the
short rostra — suggest that these creatures
could not have been active crawlers during
the greater part of their ontogeny.

The occurrence of broods of young

FIG. 1109.

Oppelia subradiata,
Sowb. Inferior
Oolite; Dundry.
Aptychus in place,
. . closing aperture

shells in the living chamber may be taken (after Owen).

FIG. 1110.

Aptychus lamellosus,

preserved as in Fi-. I his.
Upper Jura ; Solen-
hofen, Bavaria.

as suggesting that some Ammonoids were

viviparous, but the examples of this are too rare to be relied upon for making

a general statement.

Opercula. — Plates have been found in situ closing the aperture and corre-
sponding in position to the hood of Nautilus in a number of Ammonoid shells
(Fig. 1109). This positive fact, and the obvious fitness of such plates to
serve as opercula, lead to the inference that they were formed by an organ

OKI.KK II

AMMONOIDKA

540

Fl'.. llll.

similar to the hood of .V- "//////>-, and protected the animal when it nrasretJ

into the living chamber. \\ hen composed of a .-ingle

piece, the plate is called an anaptychui ; in such cases it

is invariably carbonaceous, and was doubtless horny in

the living animal (Fig. 1111). The anaptychufl is rare

in the Palaeozoic, and has not yet Keen found in the

Trias, but occurs among the Ari> !>>/•" and Amolfhcidcu

of the Lower Jura. The operculum, when formed of

two plates, is termed an aptychwi, and is always of

calcareous composition. It is noteworthy that these

plates occur uniformly in the same position among ff^

some species from certain localities, inside the living

chamber and close to the venter (Figs. 1110, 1112), a circumstance that led

Waagen to suppose tln-y
served to protect the nida-
mental gland of female
As shown by
in Oppelia, even
the embryonic
shells were fur-
nish e d with
aptychi.1

Aptychi arc
composed of
three layers, of
which the middle
one is the thickest
and exhibits a
cellular struc-
ture, whereas the
Detached apiychi

shells.
Michael

Fl«:. 1112.

Lias

Hari>iwi-<i* Lytliense, s,>\vb. sp. Upper Li
Boll, Wiirtemberg. Aptychus in living
chamber.

Fio. 1113.

.<ni/ili ifi < *i>iniiji-i

Upper Cretaoeoaa ; ^

Wi-stplialia. D. 'I
aptycluis.

Slll;ll,'V

i_/O6sieiu,

ched

1115).

two outer layers are comparatively dense (Fig.

have been classified by Zittel

into several groups according to

their structure. Celhdosi (Fig.

1114) are smooth, thick plates,

with punctate external surface ;

fmln-ii-ati (Fig. 1110) have the

surface traversed by oblique

folds or costae ; Punctati (Fig.

1115, C) have rows of punctae

and overlapping folds ; Grunnlnsi

include thin plates having the

external surface covered with

concentric folds or rows of

tubercles or spinules : Rugosi

,-,- -. , *• . , . ! | Aptychus Uuvi8,\. Meyer.

are thick plates with irregularly Havana. A, Kxt.-n.ai asi,,-.-t : /;. int.-n.ai, ' .

arranged granules or rows of

nodes on the outer surface ; Nigrescentes (Fig. 1112) are covered with a thin

1 Michael, R., Zeitschr. «leutsch. geol. Ges., XLVI. p. 697, 1894.— Retn,>-«ki, <>.. NYm-s .laln-1,.,
II. p. 220, lB9l.—BlacH-HI»lY, 11. /'., (Ie..l. .Mag. [4], III. j.. 529, 1896.

VOL. I 2 N

FIG. 1114.

Litho-i-aphir Sla1.-> ; SulrnhuS-n.

546 MOLLtlSCA SUB-KINGDOM vi

carbonaceous coating; and Coalescentes (Fig. 1113) have the two thin plates

c Fie*. 1115.

Vertical sections of aptychi belonging to A, Cellulosi (A. zonatus, Stopp.) ; B, Imbricati (A. profundus, Yoltz) ;
and (.', Punctati (A. punctatus, Voltz). 3/j (after Meneghini and Bornemann).

fused along a median depression. This last is a phylogerontic condition of
the aptychus occurring in Scaphites.

Classification. — Leopold von Buch prepared the way for a general classifica-
tion of the Ammonoidea by pointing out three grand divisions which he called
" genera." These were the Palaeozoic Goniatites, Ceratites, from the Trias and
Cretaceous, and Ammonites, from the Jura and Cretaceous, von Buch's chief
distinctions were based on the outlines of the lobes and saddles, and were as
natural and well-founded as the knowledge of the time permitted. d'Orbigny,
Quenstedt, Sandberger, and Barrande greatly increased our knowledge of
structure and variation, and defined a number of new genera.

The next marked epoch dates from the publication of Mojsisovics's great
works on the Trias, which made known a fauna as rich and complex as that
of the Jura. Suess, Neumayr, Branco, Waagen, Buckman, Grossouvre, Haug,
Diener, Douville", Kilian, Zittel, Karpinsky, the present writer, and others
made advances of essential importance along different lines. All of these
authors attempted to trace phylogenetic histories which of necessity crossed
the lines of the older classifications at right angles, and sometimes bridged
over the divisions 'of geologic time.

All classifications have necessarily been based upon sutural peculiarities.
That which is put forward below differs mainly in that it attempts to divide
Ammonoids into a number of sub-orders, named with reference to peculiarities
of the saddles,1 and lays special stress upon the phylogenetic significance of
the dorsal and internal sutures, especially the antisiphonal lobe. Although
some extensive changes are proposed, the system is in reality only a modifica-
tion of the older schemes, as will be seen from an inspection of the following
table. The latter is intended to facilitate comparisons between the primary
divisions formerly recognised and the new sub-orders, which are assembled by
means of brackets on the left into four corresponding groups.

1 The suffix campylus, signifying curve, in the names of the sub-orders, is used wholly with
reference to the saddle inflections as they appear in the typical forms of each group. The term
"Pseudoceratites," as used above, is a descriptive expression for the Placenticeratida and Tissotid/n'
of the Cretaceous, which are morphic equivalents of some Triassic genera of the Discocampyli as
regards both sutures and shell form. Their origin is traceable, however, to different groups of the
Pachycampyli, a sub-order which appears to have been initiated in the Jura along with the Lepto-
campyli. It is therefore improbable that the Pseudoceratites were directly connected with the
Triassic Discocampyli.

ORDER II

A.MMONOIDEA

TABLE SHOWIXd I'KINVIl'AL DIVISIONS OF THE AMMONOIDEA.

Infra-

f

d; -

, Zittel.

Xl.w Sri:-Oui.Ki:>.

Gastrocampyli I.

II.

Eurycampyli
Glossocampyli

sipkoZ'ta, 1 ^ocampyli
Zittel.

Phyllocampyli
Leptocampyli

Pachycampyli

IV.

KM I LVALENTfl i M'l.i: F. u:\ii i: -

< 'I,!, i,,- n in. < 'lijnicnidae (Clymenioids).
ciii: ib-order. Devonian.

Goniatitcs, Goniatitidae (Goniai i ;
/ygous inflections entire only in >impl--
form.-, becoming divided and .similar to Ceratitoidfl only
in some highly specialised «o-ncra ,,[' the rermian and
) Trias. The young are aaellate in radical form>, becoming

lati.-ellate in more -peeiali-ed X''ii--r.i. Mostly I). -vonian
I and Carboniferous ; comparatively few IVrniian p-prc-
Isentatires.

Ceratites, Ceratitidae (Ceratitoids).
Zygous inflections entire only in a few radical forms,

probably derived from the same radicals as the I'lnjllo-

campyli. Lobes become divided b\- line marginals
j forming serrations, but bases of saddles remain entire

except in highly specialised genera. Supposed to be
i mostly latisellate, becoming angustisellate in specialised
I forms. Triassic.

f Ammonites, Ammonitidae (Arnmonitoids).

Zygous inflections entire only in Palaeozoic radicals of

the Phyllocampyli. Lobes become divided by fewer and
I larger marginals than in Ceratitoids ; bases of saddles
-{ remain entire only in simpler forms of the Trias.sic

Phyllocampyli. All others have completely divided

inflections except some of the degraded Pachycamj> //?<'.

Phyllocampyli range from Devonian to Cretaceous. The
.last two sub-orders are Jurassic and Cretaceous.

Sub Order A. GASTROCAMPYLI. Hyatt.

Conchs varying from forms like Anarcestes to those that are more or less compressed in
section, and from completely discoidal to compressed and highly involute shells, thu swrfoct
being either smooth or with luni*' urines. The characteristic ventral saddles are alnnj.<t
imperceptible in some primitive species, and although entire and large as a rule, are in
some genera divided by entire ventral lobe*. S> />f" concave «/<///</ tin' m>#il j>hin,'.
Siphuncle dorsally situated. Liritui <-Ji "////«/ •<•<•<• upying about three-fourth* «f « mliifivn .
aperture with hyponomic sinus.

The ventral saddles are dc\cl ij.cd 1>\ tin- obliteration of primitive ventral lobes
and fusion of the first pair of saddles (Branco). It is at present questionable wln-ilu-i
the ventral lobes of some genera HI-- secondary modifications or retention- of th<-
primitive ventrals, and also \\lirtlirr tliesi- can In- regarded as di\ ided vciitrals even in
the Cymadymenidae. The anti>ipln> :a! loin- i- lai^e and long, and ot'h-n fusc<l with
the siplumcular funnels, whieli are long and single (monochoanitic). The dorsal .-mum-,
so far as known, are very peculiar, lias ing only a pair of large saddles confluent with
the last pair of external saddle- ; or one pair of zygous saddles, and one pair of xygous
lobes, the second pair of zygous saddles being confluent with the innenno-t ,-\ternal pair.

The perforation through the umbilicus, so constant in Nautiloids, is absent, and so
too are the umbilical depressions on either side of the neck of the protoconch, common
in other Ammonoids. The forms are nevertheless amnioniti< ones, having the pmto-
conch and other characters of the order. The first septum is described as asellate
(Branco), but figured as having a broad saddle on the venter.

Family 1. Clymenidae. ({umbel (<;?/»rm/). Primitive, forms similar to Anar-

648

MOLLUSCA

SUB-KINGDOM VI

cestes, but differing in that the sutures have broad entire ventral saddles and broad
rounded lobes ; or if the latter are angulated, they are incomplete internally, rising to
saddles at the lines of involution. Siphuncle tubular and small, and funnels com-
paratively short (G umbel).

Cyrtoclymenia (Fig. 1116),
Oxyclymenia (Fig, 1117),
Giimbel ; Platyclymenia,

JJvatt Devonian

- '

1 amily 2. Cymacly-
menidae. Giimbel (emend). Conchs similar to those of preceding family, but sutures
have two pairs of lateral saddles, and there is a ventral lobe with a median saddle.

Cymaclymenia (Fig. 1118), Sellaclymenia, Giimbel. Devonian.

Family 3. Gonioclymenidae. Conchs differ from preceding families in that

Suture -line of Cyrtocly-
tnenia laevigata, Miinst. sp.

FIG. 1118.

Suture -line of Cymaclymenia striata
Miinst. sp.

FIG. 1117.

Oxydymenia undulata, Miinst. sp.
Upper Devonian; Elbersreutli,
Fichtelgebirge.

IMC. 1110.

Gonioclymenia spa-io*", .Miinst. sp. Upper
vonian ; Schiibelhaininer, Fichtelgebirge. 1/2-

the sutures have deep undivided ventral lobes, and sometimes two pairs of lateral

saddles are present. These last may be either in part or wholly divided by marginals.

Gonioclymenia (Fig. 1119), Cycloclymenia, Discoclymenia, Giimbel; Cryptodymt'n'm,

Hyatt ; Acanthoclymenia, gen. nov. Type A. (Clym.} neapolitana, Clarke sp. Devonian.

Sub-Order B. MICROCAMPYLI. Hyatt.

Bactriticones, mimoceracones, and ammoniticones. Sutures entire, and have slight
undivided lobes on the venter, and but one pair of broad, shallow lateral lobes in primitive
forms. AntisipJwnal lobe absent in these, and the dorsal suture has a median saddle, but
this becomes divided by a small antisiphonal lobe in some forms. In more specialised
shells (Pinnacites) the lateral lobes become divided into two pairs and the dorsal saddles
disappear, being replaced by two corresponding lobes, and the septa become at th< .^inn-
time biconcave. Siphuncle subventran, and apparently without calcareous sheath.
Funnels narrow, monochoanitic, often long, but never perfectly holochoanitic. Ventral
lobes V-shaped, and remain undivided so far as known. Aperture with hyponomic */// »x.

Family 1. Bactritidae. Bactriticones and cyrtoceracones, usually
elliptical in section, and connecting through Protobactrites with the Nautiloidxi.

AMMOXOIDKA

Wissriibarh,

Nassau.

Nepionic indiv

Fi... II '.'I.

i, Bryr.
A, H,

sp. Lower Devonian;
Natural caste, >/i- (',

Sail(ll). (Kig. 11:>0>. In tlij>, )|,e ,,nly grllll.-, the -hell i-

gradually tapering, and round or mm pressed ellipti.-al in -e.-iion. Devonian.

Family -2. Nautilinidae. (Nautttmi, I ievnYh, ,„/,-,. Mini.i.-ei-a.-,,n,- and am-
monitirones, rounded
or more or less quad-
rangular in section.
Sutures have narrow
saddles on either side
of the undivided
ventral lobe, and
broad lateral lol>e>
with saddles at tin-
lines of involution or
on the umbilical
zones, when the latter
are differentiated.
Antisiphonal lobe
aliM-nt. Dorsuni with
a broad azygous
saddle. Aperture
with a deep and
narrow hyponomic
sinus, crests on the
ventro-lateral angles,
and broad lateral
sinuses on either side.

(Fig.

Mimocerc^'BjaM *^;

FIG. 1120.

ttl'itl'X I'll'lJII II*,

Upper

Biidcshoi

De-

Anar- Eifel. A, Conch, i/a.
B' Suture - line, 3/j
(after sandberger).

Fn;. U-2-2.

J//«<,'.rsto plebejus, Barr. sp. Lower Devonian (6tage
i) ; Hlubocep, Bohemia (after Barrande).

1121);

Mnia
MOja

1122, 1123); Prolo-

bites, Karp. ; Agoniatites, Meek (Aphyllites, p.p. Mojs.), (Fig. 1124);

gen. nov. Type P. (Gon.) lituum, Barr. sp. Devonian.

A narcestes subn<i >i till n us,
Hchloth. sp. Middle Devonian;
Wissenbach, Nassau (cf. Fig.
L004>

Agoniatites occultus, Barr. Lower Devonian (£tage O);
Hlubocep, near Prague, Bohemia (after Barrandr).

Family 3. Aphyllitidae. Freeh. Ammouiticones with truncated venters.
Sutures similar to those of Nautilinidae, except that a dorsal azygous lobe is present.
Aphyllites, Mojs. Type A. ambigena, Mojs. Dorsal sutures unknown. V<n-<>-
gen. nov. Type P. (Gon.) tabuloides. Dorsuin of this involute form i>

i50

MOLLUSCA

SUB-KINGDOM VI

entirely occupied by a large azygous lobe terminating in a minute annular lobe and
partial cone similar to that observed in Nautiloids and Pinnacites. The inner
extension or cone is not present elsewhere among Ammonoids so far as known.
Devonian.

Family 4. Pinnacitidae. Highly involute, compressed amrnoniticones with
acute venters. Septa biconcave, owing to division of the lateral lobes by narrow
saddles which are connected by ridges with corresponding saddles on the dorsum.
There are also saddles at the umbilical angles and on either side of the ventral lobes.
The azygous dorsal lobe is large and similar to that of Aphyllitidae. Dorsum with one
pair of narrow zygous saddles and one pair of broad zygous lobes, giving a formula of
eight lobes and eight saddles.

Includes only Pinnacites, Mojs., from the European Devonian.

Sub-Order 0. MESOCAMPYLI. Hyatt.

A provisional group including a few forms which exhibit a wide range of sutural
modifications, as well as certain genera intermediate between the nautiliform Anarcestes
with concave septa, and the normal Ammonoidea with convex septa and large lateral
saddles. Ventral lobes invariably divided; siphonal saddles entire in some primitive
genera and in a few sporadic forms among the more specialised species. Aperture with
hyponomic sinus during the later stages of ontogeny, but in some forms a ventral crest
appears during the paragerontic stage (Clarke).

The external sutures sometimes approximate to those of Anarcestes, but the dorsals
have only one large azygous lobe, the saddle being confluent at the line of involution

with the second external pair. In more involute
forms the antisiphonal lobe is large, entire, and
pointed ; there is one pair of dorsal saddles, and one
of broad dorsal lobes; the second pair of saddles,
when present, is confluent with the second pair of
lateral saddles.

Family 1. Neoicoceratidae. This in-
cludes the unique Neoicoceras, gen. nov., which
combines the lateral sutures of Anarcestes with the
divided ventral lobes of the Primordialidae, but the
siphonal saddles are large and entire. Volutions
discoidal and trapezoidal in section, similar to the
young of Gephyroceras calculiforme, Sandb. sp.
Position of siphuncle unknown. Type P. (Gon.)
elkhornensis, Mill, and G. sp. Carboniferous ;
Illinois.

Family 2. Primordialidae (Primordiales,
Beyr.). Distinguished from Anarcestes by the divided
ventral lobes, large siphonal saddles, and especially
the first lateral saddles, which are very prominent
on the sides. Adventitious lobes and saddles are

FIG. 1125. formed by division of the first lateral saddles. Septa

intumescens, Beyr. Upper in the young concave and similar to those of Anar-
~sau. A, Conch, Vi- ^, cgg^ kut in later stageg become convex along the

mesal plane as in normal Ammonoids. Siphuncle
small, subventran, without calcareous sheatli ; funnels monochoanitic and short.

Gephyroceras (Fig. 1125), Manticoceras, Hyatt; Probeloceras, Clarke; Timanites,
Mojs. Devonian. Milleroceras, gen. nov. Type M. (Gon.) Parrishi, Mill, and < :. >i>.
Upper Coal Measures ; Illinois.

OBDBBD .\MM<»N()IDKA 551

Sub Order D. EURYCAMPYLI. Hyatt.

Conchs fiinjinii in jn-imH.ii;- </./«/•</ //•«/// /V///.s like Anarcestes to hii/kln coronate
n-ith < at ire lobes and saddles. TJie ventral and lateral lobes become divided in specialised
Palaeozoic genera, and the more highly specialised Permian and Triassic forms have the
lobes and saddles complete!;/ <lir, '<!,</. Thf l<ir</r, inner saddles chara<< 'he ephebic

stage of Magnosellaridae are retained throughout life in many Palaeozoic forms, and
occur more or less in the young of Triassic genera. Among tl»' imt.r th> <•"/•<///»/. form,
of Gastrioceras is also common.

\. MAGNOSELLAKIHA.

Prevailing form of <-<>n>-li Annrcestes-like, but sometiii"-* <//><, ,/',/<//, «//</ ///-/•- ,,r less
quadrangular or tmji, :.,,!,!, il in section. Sutures entire, with large inner lateral saddles
resembling those of Glyphioceras in most Palaeozoic forms, but the lobes become more
digitated in some Carboniferous and Permian genera, and both lobes and saddles are
completely divided in highly specialised Triassic genera. Ventral lobe undivided in
primitive forms, but split by a siphonal saddle which i* in turn .^nh/lirided by in*
funnel lobes in the more specialised species. Siphuncle without calcareous sheath ; funnels
monochoantiic in primitive forms, and diplochoanitic or sometimes even cMoiochoanii
specialised Permian forms.

Primitive genera have deep undivided antisiphonal lobes and only one pair of
large broad dorsal saddles ; the first pair of lobes, when present, are confluent with
the second lateral lobes at the lines of involution. More specialised shells may retain
a pointed undivided antisiphonal, but the dorsals may have one pair of entire narrow
saddles, one pair of entire pointed lobes, and usually a second pair of saddles. These
last are broad, similar to the lateral pair, or confluent with the third laterals when
there is a third external pair.

Family 1. Magnosellaridae. Beyrich. Ammoniticones varying from discoidal
and Anarcestes-like to highly involute,
compressed shells with narrow venter-.
Septa concave along the mesal plane as
in Nautiloids, becoming convex only
internally and laterally, following tin-
broad internal saddles in the zone of
involution. Lobes and saddles entire.
Primitive forms may have only two
broad saddles on either side, but more
specialised shells may have two pairs <•(' i,-1(;. nLv,. I'M,. n-_>7.

principal saddles formed by division of yv/ioeerasj*<ror«w,v. Bucii.
the primitive first laterals.' There is a Jjfgg;rl}£on "iln> B&hF^i^

corresponding development of narrow

saddles and lobes on the dorsnm, but primitive forms have only two broad saddles

here as in Anarcest'*. Anti-
siphonal lobe narrow, entire,
~"V \/Y\/\/^V pointed. Aperture with hypo-

nomic sinus. Shells smooth.
F":- n-8- Fli;- n29- Parodoceras (Cheilor.rat,

Suture -line of >>>!••/./.,<. .".. Sutiir»'-line of Maeneceras tcre- u i\ •/• i i .>«

Afuiuteri, v. Buch. sp. bntel, Samlk s].. ^°>

1127). 8poradocenM{Fi& 1128),

Maeneceras, Hyatt (Fig. 1129); rarntn, -noceras, gen. nov. Type P. (Gon.) l> ntifnrrnc,
Kayser sp. Gonioloboceras, gen. nov. Type G. (Gon.) goniolobn^ Meek >j». /'.-•• n>l>-
clymenia, Freeh. Devonian and ( 'arboniferous.

Family 2. Pericyclidae. Involute shells resembling Glyphioceratidn,; but having

MOLLUSCA

SUB-KINGDOM VI

tlie broad inner lateral saddles divided by a pair of shallow lobes into two nearly equal
saddles. Ventral lobe in primitive Dimeroceras undivided, and this together with the
sutures indicates common ancestry with Brancoceras and Magnosellandae. Aperture
with broad shallow hyponomic sinus. Shells have annular costae crossing the venter.

Dimeroceras, Hyatt ; Pericydus, Mojs. Devonian and Carboniferous.

Family 3. Grlyphioceratidae. Ammoniticones of variable form, including dis-
coidal and highly involute shells, and also a large proportion of Anarcestes-like genera.
Septa concave along the mesal
plane in primitive Branco-
ceras, but becoming convex
as a rule along this plane in
the later stages of other
genera. Ventral lobe entire
in primitive forms, but be-
coming divided in more
specialised genera. External
sutures similar to those of
Magnosellaridae, but dorsal
sutures have narrow saddles
011 either side of the entire
pointed antisiphonal lobe.

FIG. 1130.

Suture -line of Brancoceras
sulcat-us, Miinst. sp. Upper
Devonian ; Fichtelgebirge.

Brancoceras rotatorius,
Tournay, Belgium.

Fi<;. 1131.
de Kon. sp.

Carboniferous Limestone ;

Siphuncle small, and funnels generally diplochoanitic, except in species with undivided

ventral lobes. Aper-
ture usually with
hyponomic sinus, but
some species have
ventral crests during
ephebic stages. Shells
smooth, tuberculated
or costated, but c< >si ne
do not cross the.
venter as a rule.
Venter sometimes
with well - marked
Gly&wceras*ri'"('>-";>>*, <;,,idf. iollgitudinal ridges.

sp. Carboniferous Limestone ; » '?„.

Suttrop, Westphalia. Brancoceras (± igs.

1130, 1131); Muen-

1134), Parti li'iini-c rn. ^

FK;. I 1 :;:.'.

<;<t*trioceras Jossae, M. V. K. Permo-Carbon-
iferous ; Artinsk, Ural.

steroceras, Gastrioceras (Fig. 1132), Gtyphioceras (Figs. 1133,
Schistoceras, Hyatt ; Pronannites, Haug. Devonian and
Carboniferous.

Family 4. Dimorphoceratidae. Discoidal compressed
shells ; primitive species like Prolecanites, but specialised forms
are more or less involute, although still retaining modified
Anarcestean aspect. Lobes become digitated, beginning with
the arms of the ventral lobe and progressing inwards, but
bases of saddles remain entire. The broad undivided saddles of Macjnosellaridae are

Fid. 1134.

(iti/iihifH'i'rti.x <i:<i<lri,t«, Gohlf.
sp. Carboniferous Limestone ;
Choquier, near Liege, Belgium.

olU'KK II

A.M.MoNOIhKA

iii primiti'. • .ml are more or lea traceable even in specialised -helk

Aperture with hyponomic, .-imis. Shell.- .-mooth or willi lougitndin ..

Example- : l>i,,t,,i-jiln,<; /-,(>, \,,iiii'*i,>'.' • <•• . 1 1 \. tit. ( 'arbonifi-roii-.

Family "). Thalassoceratidae. l>i-roidal and involute ammoniticone- uit'n
undivided ventral lobes in primit ivr form.-, and al-o cut in- lob,- and .-addle-; l.ut in

more specialised slid is tin- former are divided j and tin- latter digitated by marginal-,

1 nit bases of saddle- may remain entire. ( )iit liiu-s of -ut lire- in primitive form- indicate
affinity with XIHIU'«IIHH-I-I;I.<, and probable derivation from -aim- >tork. Apertniv with
liyponoinie sinus. Shells smooth.

Examples: P<nvc'///V-x, Tlml"- mn. I'ermian.

II. X.\NMTII>.\.

A 2)i'<»'i*f"i"'l <irintjiy iiirliitliiifi x///oo/A, nini-' ,,f less discoidul <nn/ <il»lio8e keelles* I
I'-ftli i>r!initir> gutures. Tli> latter pass through « M«iim»<i-ll<ir><tii x///»/.- /'// tin i/miim, i>n>
subsequently assume fl» • <i*i>i"<-t <,f Diifwrphoceratidae. /'. ////W lobes retain entire sij> li»,t<it
saddles tlirniiiilnmt ///"'. ^tic<-n>l!^-d fin-Hi^ //"/•' i-l,-r,ifi'<l subacute and often keeled venters.

Family 6. Nannitidae. Anarcestean forms with a tendency to become elevated
on the venter in later stages of growth, and having sutures with faintly denticulated
lobes and entire saddles, and with very small entire siphonal saddle-.

Xtuniiffx, rrnxjiliiiiiiift'*, Mojs. (T) Sphaerites, Arthaber. Trias.

Family 7. Otoceratidae. Involute forms with deep umbilici and prominent
ridged umbilical shoulders; venter keeled and acute. Ventral lobes divided by large
siphonal saddles. Young have volutions with broad keelleas venter and trapezoidal
section. Antisiphonal lobe, so far as known, entire on the sides and bifid at the ends.

Otoceras, Griesbach ; Anotocerax, gen. nov. Type A. (Prosph.) nala, Diener >p.
Triaa

III. TROPITIDA.

Includes a large and comparatively homogeneous group of Tri«**ic Jails of Anarcestes-
liJce aspect, but sutures with peculiarly elongated and completely digitated saddles and lobes.
tiiphonal saddles not so deeply incised by marginal lobes as tin Infinity nor very complex
i)i outline. Shell* <>rintnti'i>ti-i! //•//// costae, often tuberculated, keeled, and chatm* Lit.
Aperture invariably u-ifh l"t<r«l '•/•»-.>•/.>•. Connects through Microti-<>jn'fi* n-ith A'c-

Family 8. Tropitidae. Mojsi>o\-io ( 'r<ir*}. Similar to AHarcestJda* in the
ephebic stage, but the young lVe([iiently have volutions with highly trape/oidal

3. 113.5.

l;li, Haut-r s]>.
Trias ; Sainlli!r_.
Ausst'c, Austria.

Aussee, Austria.

(Jppei

sectiona Shells highly ornamented by the intersection of a sy.-tem of longitudinal
ridges and transverse costae. Sutures have deep, narrow ventral lobes divided by
siphonal saddles with peculiar truncated l>a>e.-, which are often retained in later stages.
Sutures in ephebic stages of some form- are -imilar to those of ll<it«riti<ln>- : young
have a more or less prolonged coronate stage, and are also keeled on the venter an a
rule. Aperture narrower and with im-iv pointed ventral crests than in //" /«/•///</,»,.

554

MOLLUSCA

SUB-KINGDOM VI

Margaritas (Fig. 1135), Tropites (Figs. 1092, C, 1100, 1136), (Pamtropites, Ana-
tropites, Microtropites), Barrandeites, Silbyllites, Mojs. ; Eutomoceras, Hyatt. Trias.

Family 9. Haloritidae. Mojsisovics (pars). Shells more globose and more
involute in the young than Tropitidae, and as a rule keelless, but having similar
volutions in a number of species during later stages. Ornament as a rule simpler than
in Tropitidae. Aperture usually with ventral crests, but these are primitive in outline,
broad, and in some species scarcely indicated by the lines of growth.

Halorites (Homerites), Jovites, Parajuvavites, Juvavites (Anatomites, Grriesbach-
ites, Dimorphites), Miltites, Sagenites (Trachysagenites), Mojs. Trias.

Sub-Order E. GLOSSOCAMPYLI. Hyatt

Primitive species exhibit close resemblance to Prolecanitidae, but differ in the greater
number and simpler forms of the tongue-shaped saddles and lobes. Specialised shells have
the saddles acute, but still entire and of the same fundamental outlines, while the lobes,
become bifid or digitated. Adventitious lobes and saddles are introduced by division of
the siphonal saddles, and generally show reminiscence of their primitive ancestral outlines.
Siphuncle as in preceding groups, devoid of a calcareous sheath; funnels monochoanitic
and short in primitive genera (Pharciceras), but becoming chloiochoanitic in specialised
forms. Antisiphonal lobe entire in primitive, but bifid in more specialised shells.

Two pairs of entire dorsal saddles and one pair of zygous lobes with rounded
outlines appear in Sandbergeroceras, but in more involute and specialised genera the
dorsal inflections become more numerous ; their outlines remain comparatively simple,
however, except in Hedenstroemitidae. There is a general tendency in this sub-order
toward the multiplication of lobes and saddles, and these are added at both external
and internal ends of the lateral sutures. The lobes and saddles are less differentiated,
or are more alike, than in preceding

groups throughout the entire lateral " A /\ m r\ (\ ,.

line. The sutures of Pharciceras, fawy\f\J\J \J \J\rrA^J \j \\\]\JV^^
however, show the presence of large *^

internal saddles in some species, indicating
derivation from Magnosellaridae.

Family 1. Pharciceratidae. More
or less discoidal shells resembling Anar-
jcestes, but having the lobes and saddles like
those of Beloceratidae, with, however,
simpler and more rounded outlines. No
adventitious inflections are developed.
Ventral lobe undivided, and antisiphonal
lobes entire. Aperture with large hypo-
nomic sinus.

Pharciceras, Sandbergeroceras (Triano-
£eras), Hyatt (Fig. 1137); Hoeninghausia,
Giirich. Devonian. (?) Beneckia,
Trias.

FIG. 1137.

Suture - line of Sandbergeroceras
tuberculoso-costatum, Sandb. Upper
Devonian.

FIG. 1138.

Lcloceras muWlobatum, Beyr. sp.
Devonian ; A<lorf, Westphalia.

Upper

Family 2. Beloceratidae. Freeh. Includes only the genus

Hyatt

oKDKll II

AM.MONOIDKA

r>:>5

FIG. 113S).

(Fig. 1188), which is highly involute ami nnnpresM-d, with Mat and narrow venter.
Sutures with nn>re or !«•.-> a.-ule ]uhe.~ and -addle-, as well a- a number »\' ad\ i-nt itious
and auxiliary iullert i'>n>. Ventral lobe divided, and fannefo monoeboanitia Aperture
with hyponomic >inus, and tin- lateral
outlines simpler than in tin- next family.
Devonian.

Family 3. Sageceratidae. Similar
to the last, but lateral lnl>e> bilid, ami
saddles acutely spade - shaped. Anti-
siphonal lobe bifid. Aperture has sinuous
lateral outlines with nv-ts at the ventm-
lateral ridges.

Pseudosageceras, Diener ; ,sW</< ,-,/•,/>,
}l'>js. (Fig. 1139). Permian and Trias.

Family 4. Hedenstroemitidae.
Principal lobes and saddles with < eratitic
outlines as in Diseocampylij but adven-
titious lobes and saddles have Say en- m*-
like outlines. Antisiphonal lobe bifid and
very long. Dorsal inflections more com-
plex than in preceding families. Aper-
ture with ventral cre>t-.

Hedenstroemia, Waagen ; Anaheden-

m , /TT j \ $<n/i-i-ci'(i.< U" liUinji'i-i, Hauer sp. Upper Trias ; Mall-

stroemia, gen. iiov. Type A. (Heden.) stadt, Austria.
Mojsisovicsi, Diener sp. Trias.

Sub-Order F. DISCOCAMPYLI. Hyatt.

Primitive genera show dose approximation to primitive types of Prolccanitidae.
Bases of saddles retain the entire rounded outlines of Lecanites even in *i»<-!,iUsed genera,
but tJie lobes become completely divided by fine marginal serrations or digUations. Tlii.<
jut fly ceratitic outline is maintained more or less in all groups except ln'iililii *p« /itlised
genera, in which the saddles are completely divided and the ctiacoeampytoc /«/. •.••>• <li*ijipear.
lobe entire in primitive, bat bifid or trifid in specialised formi^ «n<l :.itgous
imx ">•>•" mi tin <-,/•• it ;tic outline in torn* genera. I'-nfnil l<>l>i* /•//•// broad
and short, <tn</ Inn-, >•< ,-ij br<>ml .<i phonal saddles in titjiim! form*.

The number of external inflections rarely exceeds three saddles and three lobes ill
primitive forms, and the first pair of lobes as a rule is very much longer and broader
than the others. While the eternal .-addle- ..fh-ii aasume aj^iroximately nu.noi-hyllic
outlines, the dorsal saddles commonly retain the, broader and less ditl'erentiated aspect
of Lecanitidae, and saddles never become divided. The number of dorsal inflections is
more limited inmost form< than in /'//<///«m //?//,///, ami when lengthened l>y additional
inflections, the digitations are apt to be irregulai-.

I. LECANITIDA.

Compressed disco ida I mul inrolute forms. Compressed primitifa genera !<«,•, entire
sutures with broad run mini ,«^////,x mid rather narrow lobes, the ventral lobe being broad
a ml shallow, and the sipli'm«l .-•</,/,//,• also broad. Involute xln-lla »///«/W/// have pro-
longed lateral suture-lines with mi imlifmiti- number of often irregularly proportioned
inflections, which are really -marti/nul* iiriximj from the division of a prolonged -inn it-
saddle or near I it *tr«!'_ilit, ill-pressed lobe-like, inm r lim: Dorsal sutures have similar
characters and the unf/«ij>1ti>iinl l«l>-, n-l/idi /V /•/*///•»' mn> i><>ii>tn1 in ^ri mitive forms,
usually remains entire on the sides and bifid at the esfri ui''fi<.< in sy/rc/,/ //><// /'«)/•///.-•.

556 MOLLUSCA SUB-KINGDOM vi

Family 1. Lecanitidae. Primitive discoidal shells like those of
with short rounded entire saddles and lobes like those of Ibergiceras, but ventral lobes
divided by short, comparatively broad and entire siphonal saddles. There are all stages
in the development of these saddles, so that their aspect is rather variable. There are
as a rule but two principal lateral saddles and lobes, with one auxiliary saddle and
shallow lobe on either side in primitive species, but in others the number of auxiliaries
may be considerably increased. Antisiphonal lobe entire, and often long and acute.
The zygous dorsal lobes are very slight so far as known, and entire ; merely marginals
in the dorsal saddles.

Paralecanites, Diener ; Lecanites, Mojs. ; Ky mat-it es, Parakymatiteg, Waagen ;
Proavites, Arthaber. Trias.

Family 2. Badiotitidae. Discoidal and involute shells similar to Lecanitex,
especially in the dorsal sutures, 1m t with well -denned costae and keeled venters,
Includes Badiotites, Mojs. (Fig. 1140), and Doricranites, Hyatt.
Trias.

Family 3. Flemingitidae. A provisional group of discoidal
forms having longitudinal ridges as in Cladiscitidae. The char-
acteristics of Wyomingites connect it apparently with Lecanitidae,
while in Flemingites the saddles are long and have a monophyllic
aspect. There are, however, no truly monophyllic saddles at any
Badiotites Eryt, stage so far as known. The suture lines do not have the inner

Miinst. sp. Keuper ; extensions common in Gvronitidae. Antisiphoiial lobe bifid, its
St. Cassian, Tyrol.

sides entire, and zygous dorsal inflections limited in number ; but

the lobes are very broad, and their marginal saddles pointed, irregular in size.

Xenodiscus, Xenaspis, Flemingites, Waagen ; Wyommgvtesy gen. nov. Type JJ'.
(Meekoc.) aplanatum, White sp. Permian and Trias.

Family 4. Meekoceratidae. Waagen (pars). Shells smooth, compressed, dis-
coidal, and involute, and as a rule with narrow and more or less flattened venter.
Sutures in many forms have a tendency to extend the inner lateral saddles or lobesr
and to develop a corresponding series of auxiliaries ; and this is carried to an excessive
extent among some highly involute shells. The ventral lobes, however, are apt to
remain broad and shallow ; their arms become highly denticulated except in Gyronites,
where they are narrow and pointed as in Lecanitidae. Saddles entire and generally
somewhat elongated and linguiform, but plainly of the Lecanites type. Antisiphoiial
lobe, so far as known, long, narrow, and bifid so far as known. Extremities of dorsal
sutures produced and corresponding with inner parts of external sutures.

Meekoceras, Hyatt; Nicomedites, Toula; Prionolobus, Gyronites, Beyrichites, Koninck-
ites, Kingites, Aspidites, ProptycJntes, Clypites, Paranorites, Waagen ; Apleuroceras,
gen. nov. Type A. (Cerat.) Sturi, Mojs. sp. Trias.

Family 5. Prionitidae. Similar to Gyronitidae, but nodes, when they occur,
are larger, and sutures have more or less pointed siphonal saddles, Avhich are usually
divided by a siphonal lobe. Dorsal sutures, so far as known, have fewer inflections
and different outlines.

Ophiceras, Griesb. ; Vishnuites, Diener ; Prionites, Goniodiscus, Waagen ; Aploco-
ceras, gen. nov. Type A. (Din.) avisianus, Mojs. sp. Plococeras, gen. nov. Type P.
(Din.) dalmatianus, Mojs. sp. Diaplococeras, gen. nov. Type D. (Din.) liccanus, Mojs.
sp. Trias. Protophiceras, gen. nov. Type P. (Danub.) Nicolai, Diener. Trias.

II. AEGOCERATIDA.

Apparently connected through primitive forms with Protophicera*, tiltJuunjlt. xn tares of
later stages in most forms depart widely from the discocampylic outline, and are quite
similar to those of Pinacoceratidae. The auxiliary series, however, is highly inclined
apicad as a rule, and develops differently. There are no adventitious infections.

A.M.MHNOIDKA

Family 0. Ptychitidae. Similar in aspect to primitive form- of G
lull having subacute venter.-, le— complex sutures and the aii\iliar\
•i- in rrfoiiitii/"'. /'/;/<•////, x

Fig. 1141), J(l Jim, it , x,

Mojs. ; Pseudodan ni>it, .<, gen.
nov. Type P. (Danub.
,1 ritn rxh tru, Diener sp.
Trias.

Family 7. Aegocera-
tidae. Neumayr restrict.".
Smooth, compressed, dis-

roidal shells with rounded

venter in primitive forms,

becoming involute with

acute venter in specialised

-pecies. Suture.- similar in

convexity and general aspect

to iliose of Pinacoceratiilm ,

but having peculiar, highly

inclined auxiliaries which

are developed apparently

from marginals on the um-
bilical sides of the saddles ;

no corresponding adven-
titious inflections. Siphonal

saddle similar to that of

Prionitidae, and arms of the ventral lobe narrow. First lateral saddles are dependent

on, or attached to the large siphonal saddle-,
and often simulate adventitious saddles.
Aeyoceras, Waagen, s. str. (V .'//////*//'.-•,
(Fig. 1142) ; Biiddhaites, Diener
gen. nov. Type A. (Gym.) Lamarcki, Diener
sp. Paragymnit&i gen. nov. Type P. (/'
.tiikinitiild, Moj-. -p. Ti'ias.

Family 8. Hungaritidae. Involute
forms with keeled or more or le-s acute venter.
Ventral lobes remain undivided in some forms
until a late stage of growth. Specialised shell-
have a more or less extensive series of auxil-
iaries, and a few adventitious inflection-
derived from division of the siphonal saddle.

lliiinjuriii'x, (\trn //(.>-, Longobarditet) M'>j-. ;
Noetlingites, gen. nov. Type A". II" mi. X/ /•.////-
//'•'•/.-/, (Jrii-peiik >p. : Zforttes, gen. nov. T\ p.-
I. (Hung.) Pradoi, Mojs. -p. Trias.

Fie. 1141.

Ptyclii

H;IIUT p.p.). Musdiclkalk ;

Fio. 1142.

Aegoceras ( =
kalk ; Schreyer Alp, near Gosau, Austria

III. CERATITIDA.

Primitive form* i/i*<'/i/<l<tl, i'o///y//-<xxM/, ////</ }mn >•// /;//•<>• ii-ith n/iil/rnl'd ri/i/rttl lobes;
specialised forms linn tin lufd-i- diridnl^ ,i,/<l x/c7/s more or less inrnl nfr, «l*o more or less
nodose or costatecL S" <t</l<* are of the fti/n'cul discophyllie form, the lobm //x/'<///// n«.rron-,
denticulated, long, and broadening more or less at the ajn'rul ,//</.<. I*. //'/v// /--//, x in tl,,:«-
are apt to be very broad and shallow, witli (Iriitirnlufnl amtc, mul .<m<ilt ////•/»/•»/
saddles.

558

MOLLUSCA

SUB-KINGDOM VI

Family 9. Celtitidae. Primitive forms discoidal, compressed, and costated.
The costae in some cross the venter, and are also developed after a tuberculated stage
as in Sibiritidae. Sutures in these are often entire, the ventral lobe undivided (Oyclo-
celtites), and there may be but one pair of principal laterals, or at most two pairs,
with one pair of auxiliary lobes. Affinity with Ibergiceras and Lecanitidae is indicated
by the sutures of these shells. Specialised forms have smooth zones or keels on the
venter. Antisiphonal lobe entire in primitive genera, becoming bifid in specialised
forms and often very long. Costae and all characters, except sutures in some genera
(Arniotites) approximate closely to Liassic forms.

Cycloceltites, Geltites, Styrites, Tropiceltites, Arnioceltites, and perhaps Haidingerites,

FIG. 1143.

Ceratites nodosus, de Haan. Muschelkalk ; Wurzburg, Bavaria. A, B, Conch, 1/3- C, Left half of suture-
line. D, First and second lateral saddles and auxiliaries to left of line of involution (?i) ; half of dorsal suture-
line to right. (AL, Antisiphonal lobe ; other lettering as in Figs. 1096-1097.)

Mojs. ; Arniotites, Hyatt ; Florianites, gen. nov. Type F, (Gelt.) Floriani, Mojs. sp.
Trias.

Family 10. Sibiritidae. Mojsisovics. Primitive forms discoidal and often
tuberculated, giving rise to involute and compressed shells, without tubercles and with
slighter costae. The costae usually cross the venter and are often more or less con-
vergent to nodes on the ventro -lateral angles of some shells, which usually have a broad
venter and more or less trapezoidal section. The nodes disappear in later stages, when
the sides generally become more rounded, and the venter more elevated. Sutures have
divided ventral lobes, with divided siphonal saddles. Lateral inflections entire in
primitive, but in specialised forms the lobes become denticulated.

Stephanites, Waagen; Sibirites, Anasibirites, Metasibirites, I'hetidites, Mojs.; Para-
stephanites, gen. nov. Type P. (Achroch.*) atavus, Waagen sp. Pseudoceltites, gen. nov.
Type P. (Celt.) multiplicatut, Waagen sp. Trias.

Family 11. Ceratitidae. Mojsisovics (pars). Primitive forms discoidal or

AM.MONolDKA

involute, but stout-whorled ami k«-«-ile.— , beooining more compressed, ami having a broad

slightly elevated median ventral i-idge in more .-periali-.-d genera Side- liave at h-a-t
one line of nodes in primitive forms, and are more or le.-s completelv costated with
several lines of tubercles in specialised shells. Sutures in the young and in primitive
genera have a tnagnosellarian aspect, but when the broad
internal saddles become divided, the internal inllection-
resemble those of Lecanitidae. In primitive forms
(Olenikites) the saddles are broad and very -hallow ; lobes
entire, and ventral !<>be divided by a larvit'orm .-iphonal
saddle, which is sometimes entire.

The large nodes and stout volutions of primitive forms
indicate parallelism with Sfi/,/m ////,.•< and l'« rn*i, II'IKI ,nt, *
of the preceding family. Saddles and lobes have tin-
typical ceratitic outline.-, as a rule, but in some forms
the auxiliary line may be extended as in Gyronitidae.
Occasionally, also, costae may cross the venter a- in

Pa/raoen*Uutoi»odotiHtB

*

Ceratites, Haan (Fig. 1143); Danubitet, Mojs. ; Bala-
ionit es, Mojs. ; Retftingite8,Aiibsiber; Gymnotoceras, Hyatt ;
Paraceratites, gen. nov. Type P. (Cer.) elegans, Mojs. sp.
(Fig. 1144); Olenikites, gen. nov. Type 0. (Din.) spini-
plicatus, Mojs. sp. Keyserlinyites, gen. nov. Type K.
(Ger.) subrobustu*, Mojs. sp. ; Arctoccras, gen. nov. Type A. (Cer.) polari*, Mojs. ?-p.

IV. TlROLITIDA.

Primitive forms compressed, discoidal, and have only one pair of narron- >'iitir>' lateral
lobes, and tm> broad entire saddles with incomplete lobes in the umbilicus as in Parodo-
ceras. Number of inflections seldom exceeding three or four,
-and the ausilianj xntnr>'x never much extended.

Family 12. Tirolitidae. M<.jsi>.ivi«> y ">•*). Com-
pressed, discoidal, or involute shells resembling J>iimn'fi(l<i--
in their sutures, and having entire saddles and slightly
denticulated lobes. Ventral lobe may remain entire until
a late stage in some forms, but as a rule it is divided, and
siphonal saddle is small and often entire. Shells have a
line of nodes on the ventro-lateral angles, and the venter
is invariably smooth and convex.

Includes T indites (Fig. 1145) and Metatirolites, Moj-..
from the Alpine Trias. Sub -Family CLYDONITINA!:.
Suture.- similar to Tirolites, but costae interrupted on the
venter, which is often channeled. Includes {^yd,,,, //,.>-t
Eremites, Hauer ; and Ectolcites, Mojs. Tria-.

Family 13. Dinaritidae. Mojsisovics (pars).
Sutures re.-eml.liiig Tinditi'x in having only two broad
.-addles, one pair of first lateral lobes, and incomplete lobes-
at the umbilicus. Shells smooth, or with coarse folds most
" prominent at the umbilical shoulders; sides more or leas

flattened or plano-convex, and venter rounded.
Dinarites, Mojs. (?) Pseudoharpoceras, Waagen ; Pseudodiixiriii-*, gen. nov. Type
P. (Din.) mahommedanus, Mojs. sp. Trias.

Family 14. Buchitidae. Primitive forms -imilar to Celtitidae, with smooth
elevated venter ; more specialised shells with slight keel on the narrow venter, and
simple costae or folds on the sides. Sutures have entire outlines, or lobes but slightly

FIG. 1145.
Tirolites Cassianus, Quenst. sp.

560

MOLLUSCA

SUB-KINGDOM VI

denticulated ; and when the saddles are completely divided their marginals are small.
Sutures otherwise similar to those of Dinaritidae, and the young have a Dinarites stage.

Antisiphonal lobe entire and bifid in some forms.

Buchites, Helictites, Phormedites, Parathisbites,
Ghjphidites, Mojs., and perhaps Eudiscoceras, Hyatt.
Trias.

Family 15. Arpaditidae. Differs from UarJu'-
tidae in the tendency to form channeled venters
bordered by two ridges, Avlrich may be either tuber-
culose or smooth.

Arpadites (Fig. 1146), Klipsteinia, Dittmarites,
Muensterites, Steinmannites, Daphnites, Dionites,
Drepanites, Heraclites, Guembelites, Cyrtopleurites, and
Acanthinites, Mojs. (?) Bosnites, Hauer. Trias.

Family 16. Trachyceratidae. Discoidal and
involute shells with well-defined and often profusely
tuberculated costations which are interrupted on the ventral aspect by a smooth zone
or channel. This may in some specialised forms become a distinct channel bordered

Arpadites Cine n si
Esino, Lombardy.

Keuper ;

Trachyceras Austriacum, Mojs. Upper
Trias ; Rothelstein, near Aussee, Austria.

Protrachyecras An-liehins, Laube. Upper Trias (Xorian) ;
Bakony, Hungary (after Mojsisovics).

by tuberculated ridges. Lobes and saddles completely divided by marginals, but
these do not become very long nor complex.

Distichites, Trachyceras (Fig. 1147), Protrachyceras (Fig. 1148), Anolcites, Sand-
lingites, Sirenites, Anasirenites, Diplosirenites, Mojs. Trias. (?) Hesperites, Pompeckj.
Rhaetic.

Family 1 7. Tibetitidae. Compressed involute forms with channeled venter as
in Arpaditidae, but sutures generally with adventitious inflections developed through
division of the first pair of primitive lateral saddles. Auxiliary series developed by
division of the large internal saddles.

Anatibetites, Tibetites, Paratibetites, Hauerites, Mojs. Trias.

Family 18. Pinacoceratidae. Mojsisovics. Compressed, more or less involute
forms with rounded venter only in primitive species. Sutures greatly complicated,
convex, and with adventitious inflections ; also often with a corresponding series of

AMMONoihKA

561

auxiliaries. Ventral lol.e in some form.-, similar to that in '/'//•,</// /'//,/, . and mode of
generation of adventitious inflection.- in /'/,/,-//..< j-
the same as in T!l,,-t!H,l,i, . that in rfimrncercu in
unknown.

Plaritet, Bambaganiteg, /'///-///•»«•/•/•«>• Fiur- I l l'.»,
1150), Mojs. Trias

Family 19. Choristoceratidae. Discoidal
ammoiiil icones in primitive form-, heroming un-
coiled phylogeron-. and finally even complete
bartilitii-oiies in the most specialised species.
Sutures also phylogerontir, having only six entire
or very faintly denticulated loin-sand six entire
saddles. Ventral lobe divided, and the ariti-
siphonal either entire or bifid at its extremity.
Dorsal lobe* and saddles otherwise entire. Con-
nected through /W//n/(7»/.s with Jlm-ln'tr*, according
to Mojsisovies.

Polycyclus (Fig. 1151), Peripleurites, M<»js. ;
Choristoceras (Fig. 1152), Rhabdoceras (Fig. 1153),
Hauer. Trias. trta» ; Ettthetatato, new Aussee, Austria."

Family 20. Cochloceratidae. Turriliti-
cones with costae similar to those of preceding family, but more or less asymmetrical

AdL

Fio. 1150.

Pinacoceras Metternichi, Hauer sp. Kt-uiit-r; Sunienuikn-cl, near Hallstadt, Austria. Suture-line r«Hliu-i-.|
(after Haut-r).

in consequence of the asymmetry of the spire*. Lobes reduced to four in numl>er.

Fin. 1151.

Polycychis nastur-
f: ".in, i)ittinar sp.
Keuper ; Sandling,
near Aussee.

Km. 11. VJ.

Choristoceras Afarshi,
Hauer. Rhaetic; Kendel-
engraben am Osterhorn,
near Salzburg.

Fi«;. 1153.

HIliilnliH-'T"- -

Hauer. Keuiwr ;
Sandling, near
Aussee (after
Hauer).

. 1154.

Cochl*
Hauer. Sandling,

iii-ur AMSSI-I' (after
Haii.-r).

and there are other phylogerontic suppressions. Funnels monochoanitic, collars
absent.

Cochloceras, Hauer (Fig. 1154); Paracochloceras, Mojs. Trias.
VOL. I 2 O

562

MOLLtTSCA

SUB-KINGDOM VI

Sub-Order G. PHYLLOOAMPYLI. Hyatt.

An extensive series of genera having saddles with rounded outlines in primitive forms,
and as a rule with phylloidal bases in sutures with divided lobes. When the saddles are
completely divided by marginal lobes, the marginal saddles still retain the same mono-
phyllic outline. Dorsal lobes and saddles generally numerous, except in primitive forms.
Antisiphonal lobe entire only in primitive forms, becoming bifid with more or less
persistently entire sides in some groups even in the Jura and Cretaceous, but in others
they may become either bifid or trifid, and in highly specialised Triassic forms may acquire
considerable complexity of outline. The zygons dorsal saddles are commonly rnonophyllic.

I. PROLECANITIDA.

The young in this group have an ibergiceran stage (Karpinsky) with very long un-
divided ventral lobe. Primitive forms are compressed, discoidal, and more specialised
genera become involute and assume a modified anarcestean aspect. Saddles are entire in
the former, but the first laterals become very large and are subdivided by simple marginal
lobes. Lateral lobes entire in primitive genera, and become
bifid or trifid in specialised forms, but rarely have more
numerous digitations. Antisiphonal lobe entire or pointed.
Siphuncle without calcareous sheath ; funnels monochoanitic
so far as known.

Family 1. Prolecanitidae. Shells discoidal or
involute, compressed, subquadrate, or helmet -shaped in
section, but never semilunate except during the anarcestean
stage of the young. Primitive forms have undivided
ventral lobes, and rounded saddles and lobes of the
lecanitean type ; sometimes also they have large inner
saddles showing derivation from Magnosellaridae, but
there are not less than two lateral lobes. More specialised
shells have entire hastate lobes and saddles, and similar
but divided ventral lobes. Aperture with well- marked
hyponomic sinus. Shells smooth
or costated, and often with longi-
(after tudinal ridges.

Ibergiceras, Karp.; Prolecanites,

Mojs. (Fig. 1155); Agathiceras, Doryceras, Adrianites, Clino-
lobus, Gemm. Devonian to Permian.

Family 2. Noritidae. Waagen. Similar to Prolecani-
tidae, but the ventral lobe instead of becoming divided in the
usual way, retains the larval trifid stage throughout life in
primitive species. In specialised forms the larval siphonal
saddles enlarge in the neanic stage,
thus building up a single siphonal
saddle with a comparatively large
siphonal lobe. First lateral lobes may
be bifid, trifid, or completely digitated
in specialised shells, and when the
second and other lateral lobes also
become digitated the outlines are
ceratitic. The saddles, however, retain more or less of their primitive outlines, and
their bases are entire. Sutures without true adventitious inflections. Apertures
have crests at the ventro-lateral angles ; straight or with faint sutures at the venter,
but replaced by slight crests in some Triassic genera.

Prolecanites lunulicosta, Sandb.
Upper Devonian ; Nassau
Sandberger).

Schreyer-Alp, near Hallstadt,
Austria.

Fin. 1150.

Pronorites cydolobiis, Pliill.
sp. Carboniferous Lime-
stone ; Grassington,
shire (after Phillips).

York-

ORDER II

AMMONOIDEA

Paraprolecanites, Karp. ; Pronnrit,*, Moj>. . Fig.
Gemm. ; Am1>it<*, \Vaagen; N»rii>.<, .Mnjs. (Fig. 1157).

Family 3. Medlicottidae. Shells mmpn->snl, di-
ooidal, and involute, with smooth or <•< .Mated -id«-.-. and
often costated or tuU-irulated and channeled renter.
Ventral lobe entire in primith v >pe.-i.->, and tritid or
divided as in primitive Pronoritida< in more .-penalised
forms. First lateral saddles >imple 1-iit divided in primi-
tive genera, and acquire in Medlicottia through liyjn-r-
trophy and the development of marginal.- «-xtraordinary
serrated outlines. Aperture as in Pronorit /»/»/.-.

; /v</-«////v//<.,/ •/>..*. /'•//

Fio. 1159.

Suture-line of M<'iUi<;,tti,i. prlntm, W;iagen.
Carbonlferons ; .Stilt Kange, India (after Waagen).

Penno- Carbon if IT on s :
Sicily (aft.-r (J

Sicanites, Gemm.; Promedlicottia, Karp. ; Propinacoceras, Gemm.; M'i!lic<>ttt<i,
Waagen (Figs. 1158, 1159). Permian.

II. LOBITIDA.

An isolated group resembling Anarcestidae through the phylogerontic contraction of
the living chamber, but sutures similar to those of Prolecanitidae. • Saddles entire, but

the lateral lobes are bifid in the young, un>t th>-
median marginals in these lobes, becoming /"/•//</•
by growth, are often nearly equal in size to flf
more primitive laterals in ephebic stages. Anti-
siphonal lobe bifid and otJur ilnrxul inflfHinii*
entire and similar to those of Prolecanitidae,

\ ^Sh^— ~*^ /

</ Family 4. Lobitidae. Only two primi-

tive lateral lobes are developed in early m-anic
i.-1(:. 1100. sub -stages; the others

Lobite* deUMnoeepkalu,, Hauer sp. Upper arise l)>' hypertrophy of
Trias ; Sandling, near Aussee, Austria. A, /;, the SCCOlldarv marginal
External aspect, t', Median section. I), -, j-. i "• i

Suture-line, Vi- saddles, which subse-

• inently divide the primi-
tive lobes. Antisiphonal lobe bifid. Aperture in ephebic stage
normal and with slight ventral crests ; contracted and more or
less distorted in gerontic stage.

Includes only Lobites, Mojs. (Figs. 1160, 1161), from the OissVan, Tyroh
Alpine Trias.

III. ARCESTIDA.

Conchs more or less smooth, involute, rarely discoidal, invariably Anan
similar to many of the preceding groups, but with more co//////o- */'////>>-. Finally in
Arcestidae and Cladiscitidae the prolecanitean outline surn'r,* at " ml.' only in the
peculiar straightness and uniform size of the lobes and saddle*. Tin- ft'nti»n <>f mnno-
phyllic outlines in the inner saddles and in the dorsal sutures, as well as in the young
stages, occurs in some forms, however, even in these families.

Fu;. 1101.

fiitum, Miiiist. >p.
(Carniolan) ; St.

564

MOLLUSCA

SUB-KINGDOM VI

Family 5. Popanoceratidae. Shells similar to Arcestidae (except in primitive
Popanoceras, which is discoidal and compressed). Saddles have entire monophyllifc
bases, and dorsal sutures are similar to those of Prolecanitidae in sunie <^-iK-ra ; but in

FIG. 1162.

Popanoceras multistriatum, Gemm.
Permo - Carboniferous ; Sosio, Sicily.
2/3 (after Gemmellaro).

FlG< 1163'

Cydolobus Stachei, Genim. Perrno-Carboniferous ; Sosio
Sicily (after Gemmellaro).

others they become more complex and show approximation to Arcestidae. Antisiphonal
lobe trifid, but otherwise entire in primitive forms, becoming complex in specialised

FIG. 1164.

Arcestes intuslabiatus, Mojs. Upper Trias ; Stein bergkogel. near Hallstadt, Austria. A, B, External aspect.
C, Median section. D, Suture-line.

genera. Aperture with hyponomic sinus in primitive genera, but acquires faint crests
in shells that resemble Arcestidae.

Stacheoceras, Waagenoceras, Hyattoceras, Gemm.; Popanoceras, Hyatt (Fig. 1162);
Parapopanoceras, Haug ; Cydolobus, Waagen (Fig. 1163). Permian and Trias.

Family 6. Arcestidae. Mojsisovics (pars). Smooth, globose, deeply involute

A.MMoNoIhKA

506

aiiarre.-tean forms, dis.-oidal only in j.rimit ive genera. Gerontic living
usually more or le.-> « -mit rarted laterally, beenming M.met inie- -ul.anite at tin
in extreme age depre-.-.-d, and trun-
cated or concave at tlie aperture.
The latter has normally in the
ephebic >tage a lo\\- broad ventral
crest, but loses this in the para-
gerontie sub-stage, and acquire- a
ventral sinus simulating that of
Palaeozoic and more primitive
forms. Saddles and loU-s eom-
]>letely dividetl li\- more or less
complex marginals, the moiiophylli'-

outline U'illg coiujiletely olxcui-ed

except in the young, and in dorsal
sutures of -Mm- apeciea Siphonal
saddles long, and not very deeply
incised l>y marginal Io1»e>. Anti-
si phonal lobe bifid or trifid, and

FKJ. 11(35.

Joannites cymbiformis, Wulfen. Upper Trias ; Raschberg,
near Aussee, Austria. Natural cast showing living chamber
(after Mojsisovics). "

Vv:. 1166.

Suture-line of Didijmites siibglobus, ^fojs.
Upper Trias ; Someraukogel, near Hall-
sUult (after Mojsisovics).

complex in specialised forms.

Other dorsals may also become quite complex, and as a
rule are completely
divided, although of
course simpler than the
external sutures. Dorsal
sutures in the young re-
semble those of Po]>'ni<>-
ceratiilin'. Funnels chloio-
choanitic in ephebji-
stage.

Km.

Claittscites tornatus, Broun sp. Ui)p«-r Trias; stfinl».T-kogel, near Hallstailt, Austria. .1, /;, Siil«- :in«i
front views. C, Suturi'-lhif.

Arcestes (Fig. 1164), Stenarcestes, Proarcestes, Pararcestes,

Mojs. (Fig. 1165); Ithaetites, gen. nov. Type 7?. (Arc.) rhaeticua, Clark sj>. Trias.

Family 7. Didymitidae. Mojsisovics. Conchs globose like J /••,>//,/,/,, but
having growth-lines evenly concave on the sides instead of sigmoidal, and sutures \\ith

566

MOLLUSC A

SUB-KINGDOM VI

solid broad bifid saddles. The division of these by large secondary lobes is similar to
that which occurs in the first laterals of Manticoceras and Sporadoceras, but affects more
of the primitive laterals. Aperture with only short broad crests on the venter.

Includes only Didy mites, Mojs. (Fig. 1166), from the Alpine Trias.

Family 8. Cladiscitidae. Zittel. Some shells resembling Arcestidae, but
typically the sides are flat, venter plano-convex, and surface usually covered with
longitudinal ridges. Sutures similar to Arcestidae, but more complex, the saddles
being reduced in many forms to thread-like narrowness. Growth-lines like those of
Didy mites on the sides, but have crests at the ventro-lateral angles, and very broad
ventral crests.

Cladiscites (Hypocladiscites), (Fig. 1167); Psilocladiscites, Procladiscites, Paracladis-
cites, Mojs. Trias.

IV. PHYLLOCERATIDA.

Shells as a rule vrith peculiar, prominent bands of growth. Saddles in primi-
tive genera have the monophyllic bases of those in Popanoceratidae, but in more
specialised groups the marginal saddles alone retain the same rounded outlines. Dorsal
saddles and lobes are, as a rule, at least three in number. Antisiphonal lobe often
bifid, and retains either entire outlines on both sides, or with a few simple marginals^
or has but one pair of short lateral branches. Aperture with well-marked but short
ventral crest.

Family 9. Megaphyllitidae. Mojsisovics. Conchs compressed, discoidal, or
involute. Sutures with primitive monophyllic saddles, and more regular in the

relative size of the lobes
and saddles and in their
marginals than succeed-
ing families. Anti-
siphonal lobe bifid but
otherwise entire.

Monophyllites (Fig.
1168), Megaphyllites,
Mojs. (Fig. 1169);
Mojsvarites, Pompeckj ;
Discophyllites, gen. nov.
Type D. (Lytoc.} patens,
Mojs. sp. Trias.

Family 10. TJs-
suritidae. Conchs
compressed, discoidal,
and involute. Sutures

Fie. 1168.

MonophylUti'x >'/»«,//»/;, Ilauor sp.
Trias ; Rothelstein, near Aussee, Austria.

mono-
ling, near Aussee, Austria, phyllic first lateral
MiStT11"6 °f M' JarbaS> saddles, the second
laterals more or l»-s>
pointed in Ussuria. Auxiliary series remarkably irregular, and all the lateral lobes
with very large, more or less pointed, but still phylloidal marginal lobes and saddles.
Ventral lobe broad and short, and siphon al saddle very large.

Ussuria, Diener ; Ussurites, gen. nov. Type U. (Monophyl) sichoticus, Diener sp.
Trias.

Family 11. Phylloceratidae. Zittel. Principally involute shells with very
complex sutures, which, however, still retain monophyllic outlines in the marginal
saddles. Antisiphonal lobe with entire sides, or with only one pair of short lateral
branches, and extremities usually bifid.

AMMONOIDEA

Rhacophyllites, Zittel (Fig. 1170); />/</. ;/////- s, Walm.-r ; 1'L Suess (Figs.

FIG. 1170.
Rhacophyllites neojurensis, Quenst. sp. Keuper ; Hallstaclt, Austria.

Fio. 1171.

FIG. 1172.

Phylloceras keterophyttvm, Sowb. sp. Upper l>hyU<»;-,'<« ///.-A -In,;, /-„/, yu.-nst. sp. Titlmnian

Lias; Whitby, Yorkshire. Moravia. .I/., Antisiphonul 1..J..-.

>7. /, I ni a- a"- n ! l.'i AI.

Fio. 1173. Fio. 1174.

Suture -line of Phylloceras Nilssoni, Heb. sp. Suture-line of Soioerlriccras tort!snl,titii*, d'Orb. sp.

Upper Lias. (after Quenstedt).

SL, Ventral or siphonal lobe ; L, First, and I, Second lateral lobes ; a*— «, Inner or so-called auxiliary lobes ;
it, Line of involution ; Li, Second dorsal lobe; AL, Antisiphonal lobe.

1171-1173); Sou-erbiceras, Paroni and Bon. (Fig. 1174); Dasyceras, gen. nov. Type

568

MOLLUSCA

SUB-KINGDOM VI

D. (Phyl.) rakosense, Herbich sp. ; Schistophylloceras, gen. nov. Type S. (Phyl.)
aulonotum, Herbich sp. ; Geyeroceras, gen. nov. Type G. (Phyll.) cylindricum, Geyer
sp. ; Tragophylloceras, gen. nov. Type T. (Phyl.) heterophyllus-numismalis, Quenst.
sp. ; Meneghiniceras, gen. nov. Type M. (Phyl.) lariense, Menegli. sp. Trias to
Cretaceous.

Sub-Order H. LEPTOCAMPYLI. Hyatt.

Shells with peculiar, more or less crenulated ornamentation, due to the intersection of
two systems of lines, transverse bands of growth, and longitudinal creases and ridges,
sometimes developing into spines. Aspect more discoidal and larval, and with fewer
highly involute forms than in other sub- orders. Shell often constricted as in Phyllo-
campyli. Characterised in some families by the small number of completely developed
lobes and saddles. Outlines of sutures extremely complex, and saddles generally much
reduced owing to excessive development of the lobes.

The antisiphonal lobe has in most families a cruciform aspect, due to the develop-
ment of a large pair of branching marginal lobes. In the Lytoceratidae there is also
an inward growth of the two marginals near the tips, so that they rest upon the oral
surfaces of the septa instead of against the inner surface of the dorsum ; these modi-
fications being peculiar to this sub - order. The principal inflections are more
numerous in the young, and reduction takes place in later stages through arrested
development and suppression of those nearest the lines of involution. Wahner's
thorough researches have shown the close affinities of Pleuracanthites with Psiloceras
and Caloceras, which lie at the ancestral base of this sub-order. This accounts for the
similarities between the young of this group and Phylloceratidae, as demonstrated by
J. P. Smith. A number of phylogerontic uncoiled genera occur in the Cretaceous.

Family 1. Pleuracanthitidae. Discoidal, plicated, or costated shells, having
crescentic tubercles or hollow spines in some species ; venter rounded except in extreme
age of a few species, in which a faint keel appears. Aperture has a short rostrum

with deep ventro - lateral
or lateral sinuses, and
lateral or dorso - lateral
crests.

Pleuracanthites, Cana-
vari ; Analytoceras, gen.
nov. Type A. (Lyt.)
articulatum, Wahner sp.
Lias.

Family 2. Tetra-
gonitidae. Smooth,
discoidal, and involute
shells, with flattened or
rounded venter, and more
or less flattened sides.
Constrictions and spines
sometimes present. Sutures
sometimes reduced to four
paired saddles and three
lobes on the dorsum, -or
there may be only two
pairs, or a single pair of
large saddles. Siphonal lobes deeper and broader than in Lytoceratidae, the siphoiial
saddles larger, and laterals more numerous, comprising sometimes as many as nine pairs oi
complex zygous lobes and saddles. Antisiphonal lobe straight, complex, trifid, or bifid.

Fio. 1175.
Haploceras elimatum, Oppel sp. Tithonian ; Stramberg, Moravia.

OH I iKK II

AMMONOIDEA

Tetrayonites, /V,/, /„,//, ////,/,>, K-.-.mat : ^/./m//-//.-. /•"-, < Ii-..— .MVIV : /'/•• '
«,fen. nov. Type P. (A nun.') </"<"//•/-
* nli-it hi*, <\'< )rli. sp. ( 'ivtareous.

Family 3. Haploceratidae.

Zittel. Mostly involute >hells,

smooth, or with constriction.- an 1

fold-like, costae without tubercles

that commonly follow the line- ot

growth across the rounded venter

uninterruptedly. Spines -onie-

tiines present as in preceding

family. Sutures have blunt

siphonal -addles, never pointed.

First lateral lobes shallower than

in Lytocf.ratidar, the first lateral

saddles broader, and le-s deeply

cut by marginals. Anti-iphonal

lob.- long, straight, and tritid.

Lateral zygous inflections more

numerous, and there are often

three or more zygous dorsal

saddles.

Haploceras, Zittel (Lissoceras,

Bayle), (Fig. 1175). Jura and

Cretaceous. Eurynoticeras, Cana-

vari. Jura. Desmoceras, Zittel

(Figs. 1176, 1177); Puzosia,

Bayle ; Cleonoceras, Paroni and

Bon. ; Schlueteria, Hauericeras, Grossouvre. Cretaceous.

F a in i 1 y 4.
Glochicera-
tidae. Discoidal
and involute
shells, smooth in
]> r i m i t i v e
-peri,-, but ac-
quiring highly
inflected cost a -
timi.-, -oiiietinu-^
with two rows of

tubercles on the sides, and a median ventral row that may fu-e into a continuous

solid keel. One line of ventral tubercles may also arise

directly from folds that appear in otherwise unornaniented

shells. Aperture sometimes with long lateral lappets similar

to those of Oppelidae. Sutures .-imilar to Haploceratidae.
Cadomoceras, Creniceras, Mun.-('halm. (Fig. 1178); Cyrto-

siceras, gen. nov. (Fig. 1179). Type C. (Amm.) macro-

telus, Oppel sp. ; Glochiceras, gen. nov. (Fig. 1106). Type G.

(Amm.} nimbatum, Opp. sp. ; Phlycticeras (Lophoceras, Bonar. .

Ochetoceras, Haug (Fig. 1180); Cymaceras, Quenst, (Hyatt).

Type C. (Amm.) Guembeli, Opp. sp. Strigocems, Quenst. (Buck-
man); Streblites, gen. nov. (Fig. 1181). Type S. (Amm.)

pictus-costatus, Quenst. sp. Middle and Upper Jura.

Desmocerns Mayorianum,
(after d'Orbigny).

Gault ; I'erte ilu Rhone

Suture-line of Desmoceras Jut;ii'n-!«if<i,it, Mjch. Gault; Perte
u Hli< me.

Km. 117S.

Oppel. sp. Oxfordian ;

Salins, .lura.

Fio. ii7;>.
Cfrrtwfaww macro*

670 • MOLLUSCA SUB-KINGDOM vr

Family 5. Distichioceratidae. Sutures simpler than in Glochiceratidae, owing

Fio. 1180.

Ochetoceras flexuosum, v. Buch «p. Upper
Jura (/3) ; Laufen, Wiirtemberg.

Strellites tenuilobatus, Oppel sp. Upper
Jura ; Pappenheim, Bavaria.

to arrested development. Young of Distichioceras
repeat the characteristic form and costae of the latter,
with smooth venter and lateral tubercles, and then
acquire the features of Horioceras before the median
continuous keel of Distichioceras arises.

Includes Horioceras and Distichioceras, Mimier-
Chalmas. Jura.

Family 6. Silesitidae. Similar to Haplocera-
tidae, but costae more strongly developed, and some-
times spinous.

Silesites, Holcodiscus, Uhlig ; Pachydiscus, Zittel
(Figs. 1182, 1183); Parapachydiscus, gen. nov. Type
P. (Amm.) gollevillensis, d'Orb. sp. ; Pseudohaploceras,

Fio. 1182.
Patfiydiscus jyer.amphis, Mantell sp. Lower Chalk ; England.

FIG. 1183.

Pachydisais Wittekindi, Schliiter sp.
Upper Cretaceous ; Haldem, West-
phalia. 1/3-

gen. nov. Type P. (Hapl.) liptoviense, Uhlig sp. ; GabUoceras, gen. nov. Type G.

ORDER II

A.MMONOIDEA

(Amm.) Bates*, (JaMi sp. (I'nln.fniit. ('ulifurni", II., 1'U i'n, :M ; n<>n .1. //»'•-. I.. 1'i.
13); PleuropachyJ.isnui, ^cn. nov. Type P. (Amm.) Hoffman i, (!abl> .-]•. ( 'r«-t i

Fio. 1186.

A , Baculites anceps, Lam. B, B. 1
Lam. Upper Cretaceous ; Maestricht.

Fio. 1184.

Macroscaphites Ivanii, d'Orb. sp.
Upper Neocomian ; Mallenewitz,
Carpathia.

Fio. 1185.

Ptychoceras Puzo-
sianum, d'Orb. sp.
Barremian ; Vergons,
Basses Al]i"s.

Fio. 1187.

Suture-line of Dipli>mtx-er<'.-
Defr. Uppermost Cretaceous ; Tiv>villi-,
Manche.

Family 7. Macroscaphitidae. Symmetrical, closely
coiled, discoidal ammoniticones during young stages (and per-
sistently so in primitive forms), but becoming uncoiled in
gerontic stages or earlier in the ontogeny of phylogerontic forms,
and finally straight in some genera. Antisiphonal lobe short,
and in some genera trifid. Shells hav«- constrictions and large
costae at intervals, but no tubercles at any slayv.

Macroscaphites, Meek (Fig. 1184); Leptoceras, Costidiscus,
Uhlig; Tropaeii-in, S«>\vb. ; Ptychoceras, d'Orb. (Fig. 1185);
Diptychoceras, Gabb ;* Cyrtochilus, Meek (Scipionoceras, Hyatt) ;
Baculites, Lam. (Fig. 1186); Diplomoceras, gen. nov. (Fig.
1187). Type D. (Ham.) cylindraceum, d'Orb. sp. ; Anahamu-
lina, gen. nov. (Fig. 1188, A). Type A. (Ham.) subcylindrica,
d'Orb. sp. Cretaceous.

Family 8. Scaphitidae. Meek. Two or more rows of
tubercles developed in tin- i-pli.-bi.- <>r «,vrnntic stage; costae
continuous across tlic vnitrr ; ajH-rturc evenly constricted on
the sides and with a slight, brrtad rostrum on the venter,
caused by recession of the lateral curves. There is a dorsal
lappet, but this is long and bent only in Jahnnites. The
young and sometimes ephebic stages of Scaphites possess the
costae, form, and general aspect of Pachydiscus, and there are
species transitional between them.

Fi... 1188.
A, Aiiiilmtii

i/c/V", d'Orb. sp. B, Sutuiv-
line of A. I^rioli, Uhlig sp.
Neocomian ; Angles/Bassea
Alpes (after Uhlig).

572

MOLLUSCA

SUB-KINGDOM VI

Scaphites, Park. (Figs. 1189, 1190); Discoscaphites, Meek; Anascaphites, gen. nov.

Type A. (Scaph.) ventricosus, Meek sp. ; Jahnnites,
gen. nov. Type J. (Scaph.) Geinitzi, var. binodosus,
Jalm. sp. Cretaceous.

Family 9. Lytoceratidae. Neumayr (pars).

Scaphites spiniger, Schliiter. Upper Creta-
ceous (Senoniaii) ; Coesfeld, Westphalia.

FIG. 1100.

Scaphites aequalis, Sowb.
Ceno mania n ; Roue n,
France, */!•

I -•

FIG. 1191.

Lytoceras flnibriatmn, Sowb.
sp. Middle Lias; Wiirtembt-ri,'.
Cross-section (cf. Fig. 1090).

Includes only closely coiled, discoidal, and involute shells with somewhat prominent,

often crenulated transver.-e bands of growth.

Antisiphonal lobe with two long internal
branches bending inwards and attached
to surfaces of the septa. Siphonal lobe
short like that of Phylloceras, and
siphonal saddles narrow. The first
lateral saddles small and short, the first
lateral lobes much longer than the
ventral. Reduction of lobes along the
line of involution is such that there are
commonly only six to eight in full-
grown shells.

Lytoceras, Suess. (Thysanoceras,

FIG. 1192.

Lytocerus Liebigi, Oppel sp. Tithonian ; Strain berg,
Moravia.

FIG. 1193.
Alocolytoceras Genminei, d'Orb.

sp. Upper
Salins, Jure

yuo (jrC/ //Htt/tt/frj u \ji u.

Lias ; Piuperdu, near

Hyatt), (Figs. 1191, 1192). Jura and Cretaceous. Alocolytoceras, gen. nov. (Fig.
1193). Type A. (Amm.) Germainei, d'Orb. sp. ; Pleurolytoceras, gen. nov. Type P.
(Amm.) hircinum, Schloth. sp. Jura.

ORDER i r A.M.MnNnlhKA 578

Incerta sedis. AV/oo,, //•//<>, Wahner. Venter OKMMd 1-y OOttae that become
eoneave or flattened, and hordeied l.y t\\.» POW8 of tiil.eivl,- in tln-voim^; in later
Stages the venter is rounded and CTO«ed l.y OOtUw without tul.er.-h-. Sutm.- Minilar
tO those of this sub-Order. Aiiti>iph<>iial h.U- -trai^ht, liif'nl ; thefir-t |.air.,t
saddles are so large that the extremities are exteni;il to lines of involution.

Sub-Order I. PACHYCAMPYLI. Hyatt.

Shell* nffiiiiliilil (In- IK-IIII' >if Cn,, ij,l,:rit, ( in ,-i;,lntii>ii i,f i;,stnr ,,,-,>" ///••„/,-// ,/•/'//, ,

and often combined in the same forms with keeled and channeled /•• /•'• rt. 8utw
ever, are not correspondingly developed, and as regards both number »///»/ »///////< >• >,f ///.//
lobes and sa<l</l'* n n- Irs* cnnij>l,.i- tlnm in I'liiillnnmijiiil/. J.iiln-s and saddles as « mi-
shorter, broader, and less arborescent than in either Leptn,-nii,j>iili ///• /'/<////"<•" /;,y,,///.
Characterittic ////«• <>/ aiifunif <> nt/in <> " A rietean" or unequal. First /mi/- ,,f /,//,,-,»/
saddles generally broad, solid-bodied, and bifid ; first pair of lobes ii</j<,ii,i,,<i t !,,.<. />.<//////,/
much longer and larger than any others.1 Second pair of lobes ami x»/f/i//«-x il<> //«,/
develop in similar proportions to the first pair, and consequently often appro i' tu b<l<nui t<>
the later developed auxiliaries. Ventral lobe usually deep, and has a trifid or bifid
siphonal saddle, which is usually digitated throughout, and never has the elongated,
triangular, and often smooth outline of that in preceding sub-orders.

The ventral lobe becomes stouter and broader in proportion, and simpler in outline
rule in normal Cretaceous forms, and these generally have less complex sutiuv> than .Im

as a

shells. Finally, in the phylogerontic Tissotidae, Placenticeratidae, etc., the ventral lobe
becomes much broader and shorter, and the siphonal saddle is proportionally affected. The
dorsal series of inflections are almost as limited in the primitive Lower Liassic form
Leptocampyli, consisting only of one very long antisiphonal lobe, a pair of long first lateral
saddles, and a pair of zygous lobes often incomplete on the outer sides. Where the dnr>imi is
broader and more involute, however, there may be two, three, or more pairs of zygous d«>r.-nl
saddles and an equal number of lobes. These are almost invariably complex in outline, and
the antisiphonal may be bifid or trifid.

Phylogerontic forms occur sporadically in the Jura and generally throughout the Creta-
ceous. They are of two kinds: (1) Those that are retrogressive as compared with their
ancestors in complexity of sutures only. Sometimes, as in tipheniscidae and Engonoceratidac,
they are highly involute shells ; or, as in Tissotia, etc., they may be more discoidal and
nodose. (2) Those that are retrogressive as regards both form and sutures, like Xjnrm'i rut iiln, .
Crioceratidae, etc. In these the form becomes uncoiled, following out the tendencies indicated
in the gerontic stage of progressive forms. Their sutures are reduced to the primitive tnninil.i
of six, i.e. two pairs of zygous lateral saddles and two pairs of lobes, with a ventral and an
antisiphonal; but the outlines generally remain complex even in extremely modified f«>nii-
with, however, some notable exceptions like Baculina acuarius, Quenst. sp.

I. PSILOCERATIDA.

Includes only one family, comprising radicals of the Jurassic Ammonoids of thin
sub-order.

Family 1. Psiloceratidae. Smooth or sometimes plicated shells with keelless
venters. Lateral and dorsal inflections inclined ajiieud as a rule, luit vary i mi-iderably.
Size of saddles reduced along lines of involution, but there are generally three j.air> of
dorsal saddles. Ventral lobe shorter than in Leptocampyli, and siphonal saddles larger,
as in Arietidae. Aperture with a short rostrum and lateral sinuses resembling those of
Arietidae, but rostra less acute than in keeled forms.

Psiloceras has the form and shell characters of Monophyllitidae, and in subsequent stages

1 The Lentice,ratidae and Placenticeratidae furnish the principal exceptions, since they have tin-
primitive first lateral saddles beginning to split at an early stage into what afterwards .levi-
three pairs of practically independent lobes and saddles, whereas the primitive first lateral
usually persist as bifid or trifid saddles throughout life in other forms of this sub-order.

574

MOLLUSCA

SUB-KINGDOM vi

FlG 1194

Ptilocera* planorUs, Sowb. gp.

the sutures acquire phylliform marginals like those of Phyllocampyli ; but this is not in-
variably the case, and characters of the dorsal and
lateral sutures as well as of the shell vary in different
directions. In one direction they join with Caloceras
at the base of the present sub-order ; in another they
unite with Angulatida, as recognised by most observers ;
and in a third they show affinities with Agassiceras.

Psiloceras, Hyatt (Fig. 1194); Parapsiloceras,
gen. nov. Type P. (Psil) calliphyllum, var. poly-
cyclum, Waliner. Lower Lias.

II. ANGULATIDA.

Primitive discoidal shells indicate probable union
with Psiloceras, but tend to evolve forms in which the
venter is smooth, channeled, or crossed by costae at
some stage of growth even when keeled. Lateral
sutures more complex than in Arietida, and apt to be
inclined apicad in specialised shells; dorsal sutures
infra- ^^e those of Arietida.

Family 2. Angulatidae. More or less com-
pressed and costated shells, the costae sometimes

crossing the venter in the young or extreme age, but usually interrupted in the adult

by a smooth and occasionally sunken median zone. Sutures inclined apicad near

lines of involution, more complex in outline

than in typical Arietidae, and with phylliform

marginals more like those of Psiloceras.

Ventral lobe broader and shorter, with larger

siphonal saddles than Arietidae, and anti-

siphonal lobe bifid, longer, and more complex.

First pair of dorsal saddles large and long,

other dorsal inflections variable, but generally

more numerous than in Arietidae.

Schlotheimia, Bay le (Fig. 1195); Waehnero-

ceras, Hyatt. Lower Lias.

Family 3. Polymorphidae. Haug.

Shells compressed discoidal, with smooth young

like those of Psiloceras. Costae apt to be in-
clined or slightly sigmoidal, and continuous

across the venter. This is crenulated in primi-
tive forms, but becomes smooth, channeled, or

keeled in specialised shells. The latter have

sutures similar to those of Angulatidae and Liparoceratidae, but less complex.

with Psiloceras through Gemmelaroceras.

Polymorphites, Sutner ; Amphiceras, Gemm. ; Uptonia, Tmetoceras, Buckm. ;

Gemmellaroceras, gen. nov. Type G. (Aegoc.) aenigmatum, Gemm. sp. Lias and

Inferior Oolite.

L°werLias;

Connects

III. ARIETIDA.

Primitive discoidal, forms keeled and often channeled, with sides costated as in Coro-
niceras, etc. External sutures limited, as a rule, and auxiliaries rise orad toward lines
of involution, but may be considerably extended, and number of inflections increased in
highly involute shells. Dorsal sutures still more limited, and never have the monophyllic

A.MMOXnlDKA

common in Psilocercu. A'«V .->•///</ <-r«-.y</ /// ///. ///<////-/ acctlerat*
ceras, where it is hollow.

There are two types of young in .1 ri>'i !<l<i, which al'in-wanls h.-i-min- s.-parat«-.| in "ih.-r
related groups : a lu-uad depressed or coronate
type occurs in typical Arietidae and some
others, and the compressed /^>'/<>,;-,->i,i \\\»- in
Arnioceras, etc. Pscud<itrojiili'l,i, >h,.u that
Coeloceras may have originated from Arietidae
through persistent development of a trapc-
zoidal form of young with correlative changes.

Family 4. Arietidae. Voluti««n- "I
discoidal forms more quadrate than in pre-
ceding families, and often with channeled
venter. Costae more strongly developed as
a rule, and with prominent ventro-lateial
angles, which are sometimes tuberculated.
Sutural inflections reduced in number and
complexity as compared with preceding
families, and phylliform marginals re-
placed by saddles of more irregular aspect.
Ventral lobe long and narrow, with corre-
sponding siphonal saddle. Usually only
two pairs of large lateral saddles, the second often the most prominent. First pair of

lateral lobes large, second and third
pairs successively smaller ; third and
fourth pairs of saddles also smaller,
the last often partially on line of
involution. Antisiphonal bifid, very
long, and sometimes complex. One
pair of large dorsal saddles, and one
of short, often incomplete lobes.
Anaptychus observed in several
species.

Fio. 1190.
i/i, Drug, s]

Fio. 1197.
Suture-line of Coroniferas Hsulcatum, Brug. sp. (cf. Fig. 1097).

Coroniceras (Arietes, Waa^-n •,
(Figs. 1196, 1197), Vermiceras, Arnioceras, Asteroceras, Tmaegoceras, Caloceras, Hyatt
(Ophioceras, Hyatt ; Alsqtites, Haug) ;
Echioceras, Bayle. Lower Lias.

Family 5. Oxynotidae. Shells
compressed and more involute than in
Arietidae, with narrower and more acute
keeled venter, but no ventral channels.
Sutures Arietean in Agassiceras, but ha\c
extended and highly modified auxiliary
inflections in Oxynoticeras. Keel hollow
in adult of some species of the laltn
genus, and in a transitional conditi< n in
Aetomoceras.

Oxynoticeras (Fig. 1198), Ayassiceras,
Hyatt ; Cymbites, Neum. ; (?) Faroniceras,
Bon. ; Aetomoceras, gen. nov. Type A.
(Amm.) scipionianum, d'Orb. sp. Lower

Lias.

i'" i'"s

n., ,/„,,( i,-i r»*

sp. Lower I. in* (3);

Family 6. Hildoceratidae. Dis-
coidal involute shells have sigmoidal costae separated throughout or confluent on the

576

MOLLUSCA

SUB-KINGDOM VI

median lateral line, and sometimes bifurcated externally. Nodes never present,
although prominent crescentic ridges may arise on the sides through confluence of
costae. The latter are straight in primitive Catulloceras, which resembles Caloceras

Hililocerns bifrons, Brug. sp.
Yorkshire.

Upper Lias ; Whitby,

FIG. 1200.

Lioceras opallnum, Rein.
Dogger ; Te "
berg.

p. Lower
sloch, near Boll, Win-tern -

in aspect. Discoidal forms often both keeled and channeled on the venter, and
sometimes have broad furrows on the sides. Specialised involute shells have solid

keels, but usually no channels, and lateral
zones often become smooth. Sutures com-
paratively simple, and in discoidal forms
similar to those of Arnioceras, but more
complex in highly involute forms.

Hildoceras (Fig. 1199), Lioceras (Fig.
1200), Grammoceras, Hyatt; Catulloceras,
Gemm. ; Dumortieria, Haug (Fig. 1201) ;
Arieticeras, Se,g. ; Hyperlioceras, Grapho-
ceras, Brasilia, Darellia, Buckm. Upper
Lias and Inferior Oolite.

Family 7. Poecilomorphidae.
Costae in some species remain nodose on
umbilical shoulders until a late stage, and
bifurcate externally as in Oppelidae, but
subsequently may become separated into
single sigmoidal ridges like those of Hildo-
ceratidae. Young similar to those of tin-
latter family, and sutures also in discoidal
forms, but become more complex in involute shells.

Poecilomorphus, Huddlestonia, Brodieia, Cosmogyria, Welschia, Buckman; Ludwigia,
Bayle. Inferior Oolite.

Family 8. Oppelidae. (Oppelinae, Haug.) Discoidal and highly involute shell-
with sutures, form, and markings in primitive species that show affinity with Hildo-
ceran stock, and apparent derivation from Poecilomorphus through typical Oecotrauste*.
Costae highly flexed and sometimes fused, but no well-marked lateral channels as in
hollow-keeled groups. Venter often truncated and sides flattened, except in primitive

Dumortii ria,
berg.

FIG. 1201.
Upper Lias ; Heiningen, Win-ten

ORDEB II

AMMONOIDKA

Keel may lierom.- vcr\ prominent ;iinl lillel with -|»<-rial -h<-ll-layi ~, l.iit

never hollow. Youn^- generally smooth, oompreaBed, and .-imilar to tho-.- ..r ///'/,/,,-
ceratidae.
• Oecotrmitt'*, Oppelia Kig. 1100), Waagen'; Hecticocerat Lunvloeera^

Middle Jura.

IV. I'liY.MATOIDA.

Similar tn Arii'ii'in /',/ tin'/ >,!,•!, _/'/</////// /'lie/in/,:^ tome diacoidal radical forms //•//•///</
ami channels. Volution* <i<'m'i-allij atnnli-r^ I'oKtae coarser ami //>/•;/'/•, ami nl.«, mart
apt to become bifnn;if,,/ ,md to develop nodes. Young ^/,/-/v///// y ><».<.< /A/-',//,/// ,t nodose
coronate stage. Keel hollow in the adult, but solid in the young, extreme «</', ami in primi-
tive forms. Connection n-itli Oxynoticeras improbable, since the hollow keel appears to
< risen independent I if.

Family 9. Amaltheidae. Buckman, p.p. Discoidal and involute -hrll-, tin-
young of which have fold-like costae rising into heavy node- ju-t in-id<- tin- line- of
involution. Costae become prominent and sharp
at umbilical shoulders and veiitro- lateral angles,
and true tubercles appear in some Zurcherinae.
Venter keeled and sulcated in discoidal forms,
the keels alone persisting in more involute
species. Keel solid and crenulated by passage
of costae or folds across the venter. Anaptychus
present.

A. AMALTHEINAE. Nodes prominent in
young of primitive species ; costae with only
one row of tubercles in later stages or none ;
keel invariably present and crenulated. Amal-
theus, Montf. (Fig. 1202) ; Paltopleuroceras,
Buckm. (Pleuroceras, Hyatt). Middle Lias.

B: ZURCHERINAE. Young usually have
gibbous volutions with a single row of nodes,
which either persist, or are followed by a bi-
spinous stage, and inner ends of the short costae
also become tuberculated. Venter smooth at
first, and may remain so or have a solid keel.
Costae single, and usually bend at ventro-latnal
angles toward the keel, but do not cn><- th.
venter except in late stage of Pseudotropites.
Zurcheria, Haplopleuroceras, Dorsetensia, Buckm. ; Pseudotropites, Canav. ; Cana r,/ /•//,.<,
g. nov. Type C. (Ariet.) discretum, Canav. sp. Lias to Inferior Oolite.

Family 10. Phymatoidae. Discoidal forms with single or bifurcated costae,
keeled and often channeled venters. Young similar to those of Hildoccnn;,l,i,- ;nid
Paecilomorphidae in compressed forms. Keel hollow.

Phymatoceras, Hammatoceras, Hyatt ; Lillia, Bayle ; Haugia, Polyplectus, Char-
tronia, DencJcmannia, Buckm.

The type of Phymatoceras is Amm. Tirolensis, Dumortier, the so-called P. robust mn,
Hyatt, having proved to be identical with the young of that species. Upper Lias and
Inferior Oolite.

Sub-Family SOXNIXIXAK. Buckman. Sonninia includes discoidal form.- with

keeled but not channeled venter, and sides with coarse bifurcated costae diverging from

a row of nodes along the median line of the rounded -ide<, and continued internally

by single costae. Witchellia has nodes only in the young, and costae become single or

VOL. I 2 P

v.Milral Mirtaci'. This is li..iiinl<,-ous with the
black layer " of .\nntili'*.

578

MOLLUSCA

SUB- KINGDOM VI

(after Steinniai

-lti/;, Miller sp. .Middle Dogger
and Doderlein).

Lorraine

only slightly confluent. Sonninia (JFaagenia, Bayle), (Fig. 1203); Witchellia, Buck-
man. Inferior Oolite.

V. LlPAROCERATIDA.

Discoidal radical forms have more or
less subquadrate volutions with coarse,
fold-like, single, or bifurcated costae con-
tinuous across the venter. External and
dorsal sutures limited in number of in-
flections as in Arietidae, but development
of marginals carried to utmost degree of
complexity in this sub-order. Keel solid
when present. Two rows of large nodes
or spines sometimes developed on either
side.

Family 11. Liparoceratidae.
Volutions remain rounded in section and
frequently retain a primitive discoidal
aspect. Costae almost entirely disappear
011 the venter of some forms, but form
very large continuous folds in others.
Sutures become excessively complex,
saddles narrow and deeply cut by com-
plex marginals, and ventral lobe corre-
sponds, but usually of about equal length with the lateral lobes. Aiitisiphoiial bifid,

and resembles (as do also the two

dorsal saddles and small dorsal lobes)

those of Arietidae.

Liparoceras, Microderoceras, Am-

blycoceras (Microceras), Hyatt (Fig.

1204); Androgynoceras, Hyatt.

Lower and Middle Lias.

Family 12. Tropidoceratidae.

Discoidal compressed shells with

straight costae that cross the venter

in some forms approximating to Am-

blycoceras, but usually this region is

distinctly elevated, and smooth or

keeled along the median zone. Costae

have two rows of tubercles in several

species, but may be smooth in others.

Sutures similar to those of Uptonia,

but more complex ; lobes, however,

exceedingly narrow and auxiliary line inclined apicad.

Amblycoceras bifer.

Tro-pidoceras (Harpoceras, Waagen), Platypleuroceras, Hyatt ; Acanthopleuroceras,

nom. nov. Type A. (Amm.} natrix, Schloth. sp. [The latter name is substituted for

Cycloceras, Hyatt, preoccupied among Nautiloids.] Middle Lias.

VI. DACTYLIOIDA.

Young have volutions with trapezoidal sections, venter broader than dorsum and
decidedly coronate, or with a line of nodes along the ventro-lateral angles, and broad

Middle Lias

Dorsal sutures like those of

AMMoNnll.KA

umbilical but no true lnt'Tnf zoi\ a have '//• /"'•'•

throughout life. Costa<- n/>f to i» continuous u,-i;,.<.< >/ yen in .>/».r/.///.>« J _/',,/•„,,-

?/;i£& 6oM channels and AwVx. .Some genera, however, /«"••• (•<».</»/.- ,lii-i,l,;l ,,„ //,,

or suppressed, but there is no continuous nu'<li<in /•//»//;/»••/. A'-. 7 .<„//,/ ,/•/,,„ /,/,.>,„/.

Family 13. Dactylioidae. Di-euidal lorm> \\ith i-o.-l:n- l.ifnn-ati-<l and alwa\-
croasing the venter. Sutures with v.-rv .-.implex ..mlim-, l.ut only tlir«-,- or four juiir-
of lateral lobes and srnMlu.s Doi-sal >utnn-> ha\t- two pair- ,,f si«lill.-.- and on.- pair «.f
zygous lobes.

This series is usually termed tlu- 1'lonulnti <,[' tin- Lia>. l.ut althuu^li an dllVlmot <»f tin-
same common stock it is (juitc distinct from its suppo^-d cuii^.-ni-i-s of tin- Middli- and I'pjicr
Jura. Sutuvt-s an- straight, not inclined apicad as in /'- n'x/i/i <,!<•/ />/»,-. Tin- tainil\ ron,.
prises a complete cycle of forms varying fnun tin- l>n»ad liapi-xoidal, tabercalated \o)ution->
of Coeloceras through Armatoid species to A/C////W.-/VS, in which the costae are smooth and
sometimes c\.-n single.

Coeloceras, Derocera* Fit^. 1^«).~) , />»ic/////.»v/v<« (Fig. 120G;, Peronocerag, Hyatt ;
Pimelites, Diaphorites, Fucini ; (?) Praesphaerocerds, Lev! ; (?) Collii>«, Uuckm.
^liddle and Upper Lias.

Family 14. Stepheoceratidae. l.uckiiian. Primitive radicals, highly coronate,
discoidal, giving rise apparently to involute and partially compressed forms that in

I-'M;. I-JIM;.

England.

UI>I»T i.

Ki«;. 1205.

A, Deroceras subarmatuin, Y«>un^ >p.
Whitl.y, Yorksliiiv. /;, Sutuiv-lii,,- ,,t
Coelocems pettos, Quenst. Mi.l.llc Lias.

FIG. 1207.

>'/,/<«, •/•<«•«•/•(»* I', i-<iii ii n ;«r/;, Snvl».
; Bayeux, Calvados.

Inferior

Macrocephalites and some others are without tubercles. Venter always rounded,
costae bifurcating on the sides and continuous across the venter. Only one line of
nodes or tubercles at the umbilical shoulders, and division of costae takes place along
these lines in most forms. Sutures of the same type as in M/rtyh'n/W./,, but much
more complex, with usually more inflections, and lobes and saddles more nearly
equal. Dorsal sutures generally have three pairs of zygous saddles and two pairs of
lobes in coronate discoidal forms.

580

MOLLUSCA

SUB-KINGDOM VI

Stepheoceras, Buckman (Stephanoceras, Neuin. ; Cadomites, Mun.-Chaha.) ; Hphaero-

ceras, Bayle (Fig. 1207) ; Emileia, Buckman ;
Normannites, Mun.-Chalm. (Fig. 1208); Macro-
cephalites, Sutner (Fig. 1209); Sutneria, Zittel
(Fig. 1210); Erymnoceras, gen. nov. (Fig. 1211).
Type E. (Amm.) coronatum, Brug. sp. Inferior
Oolite.

Family 15. Cadoceratidae. More special-
ised, compressed, and involute forms tend to evolve
shells with crenulated keels, and sometimes channels
also. Costae of Cadoceras divided as in Stepheo-
In' ceratidae, but other genera usually develop two
lines of tubercles. Young of Neumayria more or

less costated, but sides and keel become smooth, and in some species resemble adult of

Quenstedtoceras.

This family is remarkable for the close parallelism of some of its genera with Amaltkeidac,
but the young are very distinct. Development and adult stages of Cadoceras with its discoidal

FIG. 1208.

Normannites Braikvnridgei, Sowb. sp.
i'erior Oolite ; Bay«nx, Calvados. 1/1-

FIG. 1209.
Macrocephalites macrocephalus, Schloth. sp. Upper Dogger (Callovi

i), Elmingen, Wiirtemberg.

and much depressed volutions plainly show derivation from Coeloceran stock, while its form
and sutures also show relationship with Stepheoceratidae.

Cadoceras, Fischer ; Quenstedtoceras, Hyatt ; Gardio-
ceras, Neum. and Uhlig ; Neumayria, Nikitin ; Amoebo-
ceras, gen. nov. Type A. (Amm.} alternans, von Buch
sp. Kelloway.

Family 16. Perisphinctidae.1 An extensive
series of discoidal genera having rounded or subquad-
rangular volutions, and costae single on the sides, but
split into two, three or more on the venter, which they
cross uninterruptedly. Splitting does not begin as a
rule at umbilical shoulders, but near ventro - lateral

1 Siemiradzki, /.. Monographische Beschreibung der Gattimg Perisphinctes (Palaeontogr. Bd
XLV.), 1898.

FIG. 1210.

Sutneriaplatynotui, Rein. sp. Upper
ira (Tenu/l<i!i«tii* l'»''ls); Balingen,

ii A.M.MONOIDEA 581

-s. Inner part.- of siitun- -i.-i-j.ly melim-d apir.id, and dor-.il .-itlniv- have a Imi^

Sutnn--liiic •
Ili-iii. .-]..

FIG. 1211.

Erymnoceraa coronation, Brag. sp. C;illovian ;
Xit'-vn-, France. 1/:!.

pair of first dorsal saddles, usually two additional
pairs of saddles, and two pairs of lobes. All of
these are so decidedly inclined apicad that they
often appear as a single pair of complex saddles.

FIG. 1213.

Perispliinctcs' jwlyplwua, Hi-in.
Upper Jura; PappfiihtMin, Havana.

These genera are morphic equivalents of the Liassic Dactylioidae and an- derived lV<>m the

same common stock. Young
have depressed trapezoidal volu-
tions and often minute tuheirles
on ventro-lateral angles, but are
otherwise smooth, like the young
of Cadoccras sublcr* . They In--
come compressed in m-anir >t.ix«'
and rapidly as>iiiin- tin- .lix-oi.jal
L'eris)ihinetean form and eo>tai-
without tllliel'i-les.

I' i' r ix jili inrt,'x, \\'aa<^eii

(Gross a a vria, l'mr,-riffx,
('lin/,it;-i, Si.-iiiinul.) (Figs.
1212-1214) ; Ataxioe* rat,

Font. ; I'fiijtliiinilitfx, Tei--. ;

ricfoiiin, r.ayle ;

Pavl. and Lainpl. ;

ceras, ^en. nov. Type /..

(Amm.} Ufonenrit, Oj-i

Inferior Oolite and Cretaceous.
l-'ainily 17. Aspido-

ceratidae. Zittel, p.p.

Karlicr \<»lutinn> ••...-Mli-d.
later ones with one or \\\n rn\v> <if tnliei-eli-s, tin- inner ru\v ln-in^ develnp»-d !ii-i.
A'enter broad, ncvei1 keeled. Sutures nx-mMr tliose nf I>,n-tiili<,i<l,i,-, luit sad<lles
and lobes In-oadcr and dorsal sutures with only one lari^- pair of inner or tirst <lm>al

Thin ii
Hundsriick, near Streichen,

FII . 1-J14.
•1 sp. I'ppi-r Jura

582 MOLLUSCA SUB-KINGDOM vi

lobes, the outer or second pair being incomplete in the more discoidal species as

Aspidoceraa perafmatv/m, S<nvb. sp. Oxfordian ; Dives, Cal-
vados, i/.i.

FIG. 1217.

Simocerus Volanense, Oppel sp.
Lower Tithonian ; Monte Catria,
Central Apennines.

in Arietidae. Siemiradzkia bears' resemblance in the young or throughout life to
Perisphinctes.

Aspidoceras, Zittel (Fig. 1215); Peltocems, Waageu (Fig. 1216); (?) Aurigerus,
Oppel; (?) Simoceras, Zittel (Fig. 1217); Siemiradzkia, gen. nov. Type S. (Amm.)

Normandy.

FIG. 1216.
I'thliti/, Phill. sp. Upper Callovian ; Vaches noires,

FIG. 1218.

P l> </nodoce r a s ci r c >/ nt-
spinosum, Oppel sp. Upper
Jura ; Swabian Alps. ]/"-

Bakeriae, d'Orb. sp. [Terr. Jurass. PL 149, Fig. 1 non PI. 148], Phijsodoceras, gen.
nov. (Fig. 1218). Type P. (Amm.) circumspinosum, Oppel sp. Upper Jura.

OHDKR II

AMMONOIDKA

VII. Mom-IKx KKATIDA.

Some families reseml>l, l>n<-t<ili<>i<l,i ,i,nl 1m r, *//// 11«r yottM .

distinction being the presence of n .</«/w// :.<,»< <tl<n<>\ ///- ,,\,<li«,\ y,/,»«, .,/ //..

< it li< i families very like (Josmoceratidae, but '//•//• coronal* iinn,,,/ ,!„,<' /./«//</«/

coronate adult* n/,/,,,/;- (,, /,/,,,•«• ///,/// /// ////.< sm'es.

Family 18. Morphoceratidae. (}lo))ose ami n.-nally involute forms with

open umbilici showing young to be liighly coronate until a late -tage. Cottae "ii um-
bilical /ones single and wideh

separated, but divide into verv

broad bundles of line, do>ely-

set ventro-lateral costae differ-
ing from those of all other

groups exec] it some /'./•/-

*lihiiu-H,l,n>. Only one line

of tubercles or nodes, wliii'li

usually occur at umbilical

shoulders. Kxternal and

dorsal sutures resemble those

of Periaphinctidae, but not so

uniformly inclined apicad.

In discoidal coronate shells

the lobes and saddles are of

equal length, and dorsum has

two pairs of zygous lobes and

two pairs of saddles.

Morphoceras, Douv. ;

Garantiana, Siemirad. ; Olco-

stephanus (Holcostephanus auct.), Neum. ; Potyptychites, Simbirskites, Avt'i'ritt, I'/'n/iififx,

Pavl. and Lampl. Upper Jura and
Cretaceous.

Family 19. Beineckidae.
Discoidal shells with costae single on
the lateral /ones but bifurcated on
their outer parts, and with one or
two lines of tubercles, the first
near the point of
bifurcation of the
co>tae, and the
other near their
ventral termini.
Division of costae
lakes place along
ventro -lat era 1
angles and not on
or m-ar the um-

KeiMckia Bt

Fio. 1219.
Caracoles, Bolivia (alUT Sb-iniiianii).

[nferlor Oolite ; Bayeox,

bilical shoulders.
('o>iae cross the

\cnteronlyinthe

in CoeloorK*.

Fl... lL-.'l.

!•• llaan sp. ('allovian;
*•' (after

coronate young, when >ed ion is trajnvoidal as
Sutures as in preceding family.

Reineckia (Fig. 1219), Parkinsonia (Fig. 1220), Bayle ; Oeco/////rA //<.-•, Xeum. (Fig.
1'221); Aulacostephanus, Sutner and Pomp.; (?) iramjenia, Neum., >''/•-
nov. Type S. (Amm.) niortense, d'Orb. sp. Middle and Upper .lura.

584

MOLLUSCA

SUB-KIXGDOM VI

Family 20. Spiroceratidae. Phylogerontic, uncoiled, and straight forms,
probably derived from some of the preceding family. Young are attenuated cones
with single straight costae, but have four rows of tubercles at an early stage and a
A concave zone along the venter.

Sutures of Reineckian. type, 1 un-
reduced to the phylogerontic formula
of six lobes.

Spiroceras, Quenst. (Fig. 12-2-2);
Apsorroceras, gen. iiov. Type A.
(Ham.) baculatus, Quenst. sp. In-
ferior Oolite. Incertae sedis:
Baculina, d'Orb. Oxfordian and
Neocomian.

Family 21. Hoplitidae. Dis-
coidal and involute forms with costae
bifurcated on the sides at umbilical

FIG. 1222.

Spiroceras Mfurcatum, Quenst. sp. Upper Dogger (Cal-
lovian); Ehningeii, Wiirtemberg. A, Shell with protoconch
broken away, Vi- J>, Portion of venter. C, Suture-line.

Fie. 1223.

U<.>i>Ules tuberciilal-us, Sowb.
Gault; Folkestone, Englai
Siphuncle broken away.

shoulders ; prominent tubercles at their forks, and also at or near their ventral
termini, these last being separated by a median zone or deep channel. Young of
some species have costae continuous across the venter, and resemble those of Sonneraf/n.
Parallelism with Cosmoceratidae very close. Sutures resemble those of Mammitidae,
but more complex. Lateral saddles narrower and more deeply cut, and first lateral
saddles often trifid in late stages. Dorsal series with two pairs of complex zygous
lobes and saddles on either side of a long, narrow, complex, antisiphonal lobe.

Hoplites, Neum. (Fig. 1223); Genomanites, Haug (Discoceras, Kossmat) ; Son-
neratia, Bayle ; Anahoplites, gen. nov. Type A. (Amm.) splendens, d'Orb. sp.
Cretaceous.

VIII. PLACENTICERATIDA.

Young, smooth, an 1 compressed, with flat or concave venter, which may subsequently
become acute, or remain flat throughout life, or may even become keeled. Outline apt to lie
rounded in old age; sides may have as many as three rows of tubercles, but in most
forms are not highly ornamented. Sutures remarkably complex in some families, but in
others extremely simple, recalling those of Triassic genera. General tendency is to extend

ORDER li

AMMnNolDKA

//,,• futures iiifi finillit, anil tn nmll/'j,/,/ „ ,i ,„!„,• ,,f /,,/„> ,i,nt
i.i-ti-rniillii it/nl mi tl/, <lt>r*n in. /•'//•.<;/ lnt,/;il .«/(/<//..>• n/it t<>
three di*tini-t

Family -J.-1.

in prOpOfftOB) /'"'/'
in l<it> /

Sphenodiscidae. Suture- -lightly more romp]e\ than tho.-e
and \\ith phylliforiii marginal-; dor.-al- nionophyllir.
to those of Engonoceratidcki

in ]>rimitive species, and have con-
cave venter.- and rompiv--ed volu-
tions. Venter subaeute or keeled

ill the adult, but later lo-e- ii- keel,
and becomes plano-convex or
rounded.

Sphenodiscua, Meek; /"//</<«•< r«*.
Xoetling ; Libycocera^ gen. nov.
(Fig. 1224). Type L. (Spkm.
Ismaeii, Zittel. Cretaceous.

Family 23. Placenticera-
tidae. Tuberculated and smooth
forms, the young of which pa--
through a stage \vith smooth, Hat,
or concave venters similar to adult
of Engonoceras. Venter remains
flat or compressed until old age,
when it becomes rounded. Sutures

remarkable for their complex, D^^[^ SXS.'
irregular, ragged outlines, and

narrowness of saddles. Their outlines in the young very similar to those of fy//./' —
discidae.

riticenticeras, Meek ; Diplacomoceras, gen. nov. Type I). (Amni.) 1>i<l»rfnin*.
Schliit. sp. Cretaceous.

Family 24. Engonoceratidae. Compressed shells witli numeroii.- sadd:
e'incave or flat venter. Costae nodose in Mum- .-jiecit-s, but usually fold-like and
sometimes merely broad, low lateral >wellings. Sutures >impler than in >'/-//'/'"-
discidae, but of the same type.

Engonoceras, Neum. ; Knemiceras, Bo'lim ; Xeolobites, Fisi-lu-r : /'/•»,/.
gen. nov. Tyj.e /'. (A nun.) (,'<ihl,,\ Hyatt = Amm. jt,-<l>Tii<ili}i, Clabb.

' Ii;- 1"4-
Libycoceras Ismaeli, Zittel sp. Upper SeiKiiiian ;

Libya

IX. ACANTHOCKKATIOA.

A series of more or less uncoiled genera connect"/ tJinmiil, tl,, trnn*itii>i<iil A>-'Hitli<)-
ceratidae with normal Cretaceous *//"//* Jmring costae inti>rni}if><l m> flu' ri'nl<r «f mmh-
stage or throughout life, although in most forms cmtimniii* during later stage* »f tl<.
ontogeny.

Family 25. Acanthoceratidae. Young slender, discoidal, without inl-
and section rounded until late in neanic stage. Sutures have diM-ply-.-ut outlines,
and owing to frequent presence of only >i.\ lolu-s and saddles simulate those of
Leptocampyli, but are not of tin- same type. First lateral >addle> l>n»ad and
bifid; ventral lobe straight, deep, and has a trmic-utrd .-iph<>nal saddle. lv\t«-rnal
characters similar to some forms of Jf<i/>lifiil<tfi. Some species have costae bifur-
cated, more or less interrupted, and with only the ventm-lateral row of tuherde.-
or none.

Acanthoceras, Neum. ; 77n/ /•///<'/////-/, gen. nov. Type '/'. (Amm.) TIinn,ni,i,,i, Pi-t.

586

MOLLUSCA

SUB-KINGDOM VI

and Camp. ; Lyticoceras, gen. nov. (Fig. 1225). Type L. (Amm.~) cryptoceras, d'Orb. sp. ;
(?) Vascoceras, Choff.1 Cretaceous. *

Family 26. Hamitidae. A provisional group of uncoiled shells having single
£ostae crossing the venter uninterruptedly > and no tubercles at any stage.

Hamites, Park. ; Hemibaculites, gen. nov. Type H. (Toxoc.) obliquatum, d'Orb. sp. ;
Dirrymoceras, gen. nov. Type D. (Ancyl.) simplex, d'Orb. sp. ; Torneutoceras, gen. nov.

Fi.;. 1225.

Lyticoceras Noricum, Sowb. sp. ( = Hoplites anMygonius, Neuni.).
Neocomian ; Achim, near Borsum, Prussia.

Fi.:. 1226.

Torneutoceran

Sowb. sp. Gault; Folke
stone.

(Fig. 1226). Type T. (Ham.} attenuatus, d'Orb. sp. Possibly here also should be
placed Helicoceras and Heteroceras, d'Orb. ; and Lindigia, Karstens — all asymmetrical
spirals, but in old age forming a secondary crook striking off from the spire.
Cretaceous.

X. COSMOCERATIDA.

Highly taberculated and costated forms having a smooth zone on the venter or costae
extending across it, but never with a line of median ventran tubercles nor a keel at any
stage. Numerous phyloyerontic uncoiled forms occur in the Cretaceous.

Family 27. Cosmoceratidae. Discoidal and involute forms having at a
comparatively early stage or throughout life two or three rows of large tubercles
on each side, and costae interrupted on the venter by a smooth median zone or
channel.

Late stages of all genera except Cosmoccras and Phricodoceras have costae continuous
across the flattened venter, and species of the latter indicate possible transitions to
Amblycoceras. All forms have a Cosmoceran stage quite distinct from the young of
Morphoceratidae.

1 P. (jho/at. Receuil d'etucles paleontologiques sur la fanne cretacique du Portugal, Les
Ammom'es du Bellasien, etc. Lisbonne, 1898.

ORDKR II

AMMONOIDKA

B87

Cosmocero*, Waagen Fj«r. li'27.-; /'// /•/><„/,„ v,-,,x, gen. nov. Tyj.e /'. Amm.)

Taylori, d'Orl.. .-p.: Stgaloccras, gen. nov. Type N. (Amm.) oalkvinue, d'Orb. .-p.

Middle Lias to Oxfordian.

Family 28. Pedioceratidae.

Young resemble (\^ninc,'rnHtl,i>^ but later

the large single or imperfectly bifurcated

costae are apt to cross the venter. Some-
times all traces of tubercle- are lost, but

most forms possess until a late -tag" a ro\\

on the veil tro-lat era 1 angles, another in

juxtaposition to thi> externally, and either

two more or none inside these rows.

Pedioceras, (lerh. : Itiniri/l, !>•< r«.<,

<!n»ss. (Fig. 1228); Steueroceras, Cos-m.

(Odontoceras, Steiien : l>i,uli,rlin<-i-nix, gen.

nov. Type D. (Amm.} //,Wnx,,tw/f //////,

J'Orb. sp. Cretaceous.

Family 29. Anisoceratidae. Tncoiled shells with only two row- of

on either -ide. and costae
similar to those of preceding
family. The adult Aniso-
ceras has a Helicoceran
aspect, develops a long,
eccentric Toxocera*-\\ k e \ < >\ u -
tion in the gerontic stage,
and terminates with a n-t ro-
ve rsal bend or crook.

Anisoceras, Pict. ; Tono-
ccrti^ gen. nov. Type T.

,.. 1228.

DouvUlefoeras iimiiu/lmr. Sclilotli. sji. (iaiilt ; .Mai-hiToiiK'-nil, Anli>

Duvalianum, d;0rl>. sp. ; Hyphantoceras, gen. nov.
Type H. (Heteroc.) ^o/.s-.<//r/ //»///, Sdiliit. .-]). Cretaceous.

Family 30. Turrilitidae. Tnrriliticones having
more or less angulatel volutions, with two rows of
tubercles on either side of the median line of the venter.
Shells close-coiled from the earliest - age, or with only a
slight eccentric deviation in old age; often partially
costate, and sometimes with only three POWB »f tubercles
in older stages. Aperture much elongated iransvei.-el\,
and contracted in extreme age of Tnrrilites by ingrowth
of the right side. Costae continuous across the venter Tvrrtliti <r«>ri».

or interrupted by a smooth zone, and either single or IS',1
divided between the rows of tubercle.-.

Tnrrilites, Lam. (Fig. 1229) ; Ostlingoceras, gen. nov. Type t). (Tun:) I'ttzvsianum,
d'Orb. sp. Cretaceous.

Family 31. Ancyloceratidae. Includes only such forms usually a-signed to

588

MOLLUSCA

SUB-KINGDOM VI

Ancyloceras, Crioceras, etc., as have three rows of tubercles on either side on the larger

costae. Between the latter are smaller costa-

tions without tubercles. Costae sometimes

interrupted across the venter by a smooth

zone.

Ancyloceras (Fig. 1230), Hamulina, d'Orb.

(Type H. dissimilis, d'Orb.) ; Pictetia, Uhlig ;

Helicancylus, Gabb ; Distoloceras, gen. nov.

Type D. (Hopl.} hystrix, Xeum. and Uhlig

sp. ; Acrioceras, gen. nov. Type A. (Ancyl.}

Tabar'elli, Astier sp. Cretaceous.

Family 32. Crioceratidae. Volutions

more or less

roughened and

costated, with

only two lines of

tubercles on either

side of the median

line of the venter.

The latter may

have a smooth

zone or be crossed

by the costae,

which are either

single or double

between the

tubercles.

C r i o c e r a s,

d'Orb. (Criocera-

tites, Lev.) ; Oxy-

beloceras, gen. nov. Type 0. (Pty.} crassum, Whitf. sp.
Cretaceous.

Family 33. Nostoceratidae. Adult spirals
asymmetrical turriliticones, with more or less prominent
costae and one row of tubercles on each side of the venter.
Extreme gerontic stage often retroversal, the return being
in some cases complete, so that aperture is brought close
against base of the spire. Young of Emperoceras may
remain Hamitean for a prolonged period, and then suddenly become Helicoceran or
turrilitiform.

Nostoceras, Emperoceras, Didymoceras, Exiteloceras, Hyatt ; Bostrychoceras, gen.
nov. (Fig. 1231). Type B. (Heteroc.} polyplocum, Schliit. sp. Cretaceous.

FIG. 1230.

Ancyloceras Matheronianmn, d'Orh. Neocomian ;
Castellanc, Basses Alpes. A, Concli. B, Suture-
line.

1231.

Bostrychoceru* polyplocum,

Cretaceous;

XI. MAMMITIDA.

Shells closely parallel to Cosmoceratida, but differ in having at some stage a median
line of tubercles along the venter. These are fused in more specialised genera into a solid
entire keel.

Family 34. Mammitidae. Differ from Pedioceratidae in that the ventvr is
rounded and smooth in the young, after which a median ventran row of tubercles
appears, or a keel resulting from their fusion. Sutures have larger and more solid
saddles than in Pedioceratidae, and first lateral saddles generally bifid.

Mammites, Laube and Bruder ; Muniericeras, Gross. ; Barroisiceras, Gross. ;

oKDKK II

AM.MONOIDKA

< '.ill/,-,,,-, •/•/>.-•, gen. no\-. Type ' '. A 111 in. //.//•/.•(» /«//•/.«;. sii.-u-ji ip. ; Metacanthoplifaj getL

nov. (Fig. 1232). Type

.V. (J.MW.) rhotiniKi -

i/ofs/X d'Orb sp. Cre-

taoeous.

Family 35. Peroni-
ceratidae. Similar to

M<( in iilit i<lii>> in general

aspect and ornamenta-
tion of adult stage, l>ut
young liave a distinct
kci-1 and a coi-oiiatt- funn
with lu-avy
('•istai- gt'iicrally
tomous,and vciitt-r i
lias channels or
zones on either >idc of
the keel. Sutural out-
lint-s n iore complex than
in M<i in initidae.

Peroniceras, Gau-
thiericeras, Gross. ; Hy-
strichoceras, gen. nov.
(Fig. 1233). Type H.

(Amm.) Coupei, Brongt. sp. ; Dipoloceras, gen. nov. (Fig. 1234).
cristatum, d'Orb. sp. Cretaceous.

Family 36. Prionotropidae. Young resemble some forms of Mn mm ///W«<, luit
have a crenulated keel at an early stage, which is persistent. Costae usually liner and

Metacanthoplitea

(after Quenstedt).

FIG. 1232.
Rhotomagense, Uefr. sp.

Fninct-

Type I >. (Amm.)

Cenomanlan ;

Fi.i. 1--34.
i-,-;.itntii)ii, Deluc sp. l.(

Hystrichocenu variant

Quedlinburg, Saxony.

more closely set, and tubercle.- -mailer than in that family. Spines l.ecmne very large,
volutions more quadrate in section, and venter Hat with prominent keel and channels
until a late stage. Dorsal sutures reduced in discoidal forms to one pair of large
saddles and one of incomplete lobes on either side of the ontisiphonaL

Prionotropis, PrionocyduS) Mortoniceras, Meek; Sctdo«nbackiat Xeum. ;Type N.
Germari, Eeuss.). Cretaceous.

590

MOLLUSCA

SUB-KINGDOM VI

Family 37. Hystatoceratidae. Similar in general aspect to Peroniceras.
Young compressed, smooth, and keeled until a late stage; they then become costated,
venter loses its keel and is crossed by fold-like costae. Sutures simpler than in
preceding families and resemble Tissotia except that the first lateral saddles are
symmetrically bifid. Dorsal sutures have at least two pairs of zygous saddles and one
of zygous lobes ; sometimes three pairs of saddles and two of lobe.-;.

Hystatoceras, gen. nov. (Brancoceras, Steinm. non Hyatt). Type H. (Amm.)
Senequieri, d'Orb. sp. ; Hysteroceras, gen. nov. Type H. (Amm.) varicosus, d'Orb. sp. ;
Falloticeras, Par. and Bon. Cretaceous.

Family 38. Lenticeratidae. Young smooth, keeled, discoidal, and resemble
preceding family, but adult sutures like those of Placenticeras. Saddles very broad

and comparatively solid, the first laterals
usually with three arms. Arietean lobes not-
present. Adventitious saddles arise by division
and outgrowth of the ventral or outer sides .of
the first laterals as in Tissotidae.

Lenticeras, Gerhard ; Paralenticeras, geii,
nov. Type P. (Amal.) Sieversi, Gerhard
sp. ; Platylenticeras, gen. nov. Type P.
(Oxynot.) heteropleurum, Neum. and Uhlig sp.
Cretaceous.

Family 39. Tissotidae. Primitive forms
have tuberculated costae and keeled venters,
the keel probably having originated by coal-
escence of a median line of tubercles. Sutures
usually very simple, sometimes similar to
P idchellidae, and first lateral saddles apt to be
unequally bifid. Adventitious saddles appear
in some forms, but arise by division of t In-
cuter sides of the first laterals instead of from
their inner sides as in. Placenticeratidae.

Tissotia, Douville (Fig. 1235) ; Psilotissotia,
gen. nov. Type P. (Pulch.) Chalmasi, Nickles
sp. ; Lopholobites, gen. nov. Type L. (Neol.)
Cotteauxi, Nickles sp. [? Hemitissotia, Plesiotissotia, Heterotissotia, Peron. Names only
reported in Revue Grit. Pal. 1899.] Cretaceous.

Incertae sedis : Buchiceras, Hyatt ; Mojsisovicsia, Steinmann. Cretaceous.

Tissotia Fourneli, Bi
el-M'.sai, Algiers (after

FIG. 1235.

le. Cenomanian ; Mzab-
ayle).

Range and Distribution of the Ammonoidea.

Not less than 5000 species of Ammonoids have been described, as contrasted with
about 2500 of Nautiloidea. The distribution of these amongst the different sub-orders
may be briefly indicated as follows : (1) The Gastrocampyli are an aberrant stock con-
fined to narrow limits of the Upper Devonian, and restricted geographically to a few
localities in Germany, Russia, and England, with only a single species from the
United States.

(2) Goniatitoids. — The Microcampyli comprise primitive ancestral forms of Ammo-
noids, and are confined to the Devonian system. The Mesocampyli are an aberrant
division occurring in both the Devonian and Carboniferous systems, and for the most
part enjoy a wide distribution. The most highly specialised family Pinnacitidae is
limited, however, to only a few European localities. The Eurycampyli is by far the
most important group of Palaeozoic Ammonoids, and is represented throughout the
Devonian and Carboniferous of both hemispheres by typical Goniatitoids. The

OILDBH ii A.MMoNolDKA

Permian ami Tria^.-ic genera h>-iv a—., iated in lln- .-aim- ,-ub-ordei -an- parallel with
normal Triussir ( Vrat itoids, ami have a wide di.-t ribut ion in tin- Tria-. The '
<•«////>//// is an aberrant stock \\ith pe.u liar sutures. They be^-in in tin- Devonian, Inn
have not, yet been traced with certainty in tin- ( 'arboniferoii-. The\ re.ippear, liow1-
ever, in tin- Permian, ami arc represented by a Dingle family in tin- Tria- of India and
Northern Siberia. Tin- Devonian ami Permian genera arc widely di-t ributed.

(3) Ceratitoula. --The sub-order l>is,;,,;iinjiiili i- re-tridcd to tin- Tria- \\ith the
exception of a single family, /•'/» /////* iiiti<ln<; which occur.- in tin- Permian of India
and North America. The form- have a world-wide di-t ril.ut ion, and are e.-pecially
numeroiis in India and the western l/nited State.-. Tin- group attain- the acme of
specialisation among Ammonoids, as shown l»y their extremely complex -ntnie- \\ith
numerous lobe< and .-addle-, comliincd with a highly ornamented exterior and con-
siderable modilicatioii of form. The numlier of ret rogressive or phylogerontic

i- also very small.

(4) Ammonitoids. — The Phyllocampyli include the supposed ancestral and piimiti\e
forms of typical Ammonoids, and begin, with the family Protoani&fcu, \\hich

from the Devonian to the Permian. Three primitive offshoots of this family aie
present ill the Permian, two of which persist al.-o during the Trias. In all, nine
families of Pkyttocampyli occur in the Trias, only one of which (PhyUoceratida*
continues throughout the Jura and Cretaceous. Most of the families have a world-
wide distribution in the several formations where they occur. The sub-order rea<he- a
high degree of sutural complication, and this, together with the number of lobes and
saddles in the Phylloceratidae, mark them as being among the most progressive <>t
Ammonoids in respect to sutures. Their shells, however, are very simple in comparison
with either the Discocampyli or Pachycampyli.

The Leptocampyli are obviously a retrogressive series. They bc^in at the i
the Jura with forms having a restricted number of lobes and saddles, and terminate in
the Upper Cretaceous with two families of uncoiled phylogerontic .-hells. The com-
plexity of the sutural outlines is, however, constantly maintained, as i> especially well
illustrated by Lytoceratidae, where the arms of the antisiphonal are curinu-ly pro-
longed. Their distribution coincides with that of the riiyllm-i'infiilf, and tl,
quite abundant in certain Jurassic and Cretaceous localities

The Pachycampyli are usually considered as the typical and al>u mo.-t <
forms of Ammonoids. This is true as regards the immense number and variety of
modifications in form and ornament displayed by their shells and apertures ; but the
sutural inflections are on the average less complex both in outline and number of
lobes and saddles than those of the Phyllocampyli, although both group.- are evident 1\
derived from the same stock.

By the term progression, as used above, is meant '• evolution of structures increasing
by differentiated additions," such as the addition of more complex inflection!* to either
the dorsal or external sutures, increase in the amount of involution, or the introdm -
tion of keels and channels on a primitively convex venter, etc. Retrogression signifies
"evolution through the reduction of such progressive characters," whether taking
place locally or generally in the organi-m or throughout the group. Retrogression, in
this structural sense, does not imply actual reversion to ancestral conditions, except in
so far as the disappearance of a part or organ necessarily produces a certain r« -emblam e
to their ancestors before the parts or organs in question were evolved. Kxamjde.- will
be found on comparing Baculites with Bactrites, Mimoceras with Criocera*, etc. In
this sense Ammonoids experienced a progressive evolution from the early Devonian
until the Upper Trias, when the first signs of general retrogression are ob-ened, and
a few uncoiled and turriliticonic genera appear.

Following their culmination in the Trias, Ammonoids display in the Jura a
mixture of retrogressive with some progressive features. Part of their losses are
regained by the evolution of a vast number of forms and modifications during this

592

MOLLUSCA

SUB-KINGDOM VI

period, but there are numerous localised signs of retrogression, due perhaps to un-
favourable surroundings. Indications of this kind occur sporadically throughout the
Jura and become general in the Cretaceous, leading us to infer a widespread unfavour-
able change in their physical surroundings, .similar but more extensive than that which
affected European forms during the Inferior Oolite. To the latter influence should '
probably be ascribed the uncoiling observed in the Spiroceratidae. With the close of
the Cretaceous all species disappear for ever from the pages of geological history.

TABLE SHOWING KANGE AND PRESUMABLE KINSHIP OF
AMMONOID SUB -ORDERS.

Cretaceous

|

5g

1

r

|

^

Jurassic

Qu

Q>

"1

^

—

Triassic

1

1

§

Permian

Q

Carboniferous

? 1:

|

!

1

Devonian

g s

i

§

- ^

M

>1

In ' A

s
H

3

^

PW

^S-

J

licro-jcampyli

[Professor Hyatt's revision of the Nautiloids and Ammonoids for the present work
terminates at this point. The classification and diagnoses are condensed from an exhaustive
Monograph on fossil Cephalopods, at present still in MS., which embodies the results of his
life-study. Reference should be made to this work, when published, for a more complete
account of families and genera than it has been possible to give in the preceding p;i.ir< -s.
TRANS.]

Sub-Class 2. DIBRANCHIATA.

Cephalopods with only two arborescent gills in the mantle-cavity ; provided ron wi-
the mouth with eight or ten arms bearing suckers or hooks, two of them (when ten in
all are present) being often developed into long tentacles. Funnel dosed; ink -sac
usually present. Shell internal, or if external, is not chambered ; in many forms
entirely wanting.

SUB-CLASS II

Dir.KANclllATA

The body of Dibranchiates or Cuttle-fishes is elongated, cylindrical, or
sack-shaped, and frequently provided with two lateral fin-like appendages.
The anterior cephalic region gives off a circlet of eight or ten powerful,
muscular arms, the inner sides of which are armed with suckers (an-f"l>»
a double row of hooks, and assist in swimming or creeping, and also serve for
the capture of prey. The Sepioulea have two of
their ten arms developed into very long tentacles
which bear hooks or suckers only at their thickened
extremities (Fig. 1236). The lower surface of
the suckers is disk- or cup-shaped, perforated in
the middle, and occupied by numerous radially
arranged muscle fibres ; they are also occasionally
furnished with horny hooks or sharp claws. Each
sucker is able to create a partial vacuum by
pressing the cartilaginous rim against some object
and then contracting the inner folds, and hence
can be used like a cupping-glass.

The jaws resemble those of Nautiloids in
form, but are never calcified ; owing to their
perishable nature, usually horny, they are not
preserved in the fossil state. The cartilage of
the head forms a complete ring enclosing the
central portion of the nervous system. The eyes
are of a large size, protected by a capsule, and
recall those of vertebrates in structure.

The body is constricted at the mantle opening,
which occurs just behind the head, and at this
point on the ventral surface is placed the respira-
tory orifice, bounded by a projecting fold of the
mantle. Here also terminates the cylindrical or
conical funnel, on either side of which lie the
dendriform gills ; in the same neighbourhood too S*l8U&Btt. At V
are placed the anal and genital openings.

The abdomen is sack-shaped, and contains besides the viscera and circu-
latory systems a rather large pyriform vessel called the ink-bag. Its reservoir
is filled with an extremely opaque brownish-black fluid, which can be voided
at will through an excurrent canal terminating near the anus. Menaced or
alarmed, the creature discharges an impenetrable cloud of ink, which serves to
conceal its retreat. % One often finds within the body of fossil Dibranchiates
not only a cast or mould representing the ink-bag, but often a dark-coloured
residuum of the carbonaceous particles suspended in the ink.

The abdomen is completely covered by the mantle, which is a thick and
frequently brilliantly coloured muscular envelope. Traces of it are occasion-
ally found among fossil forms, owing to a slight secretion of calcareous matter
within it.

Most Dibranchiates secrete an internal shell within the mantle. Only
among the Odopoda is a shell absent entirely, or replaced in the female by a
thin, simple, unchambered spiral ; but this last is in nowise homologous with
the usual Dibranchiate shell. Spirilla has a spiral, camerated shell, the septa
of which are traversed by a siphuncle, and whose coils are not in contact. It
VOL. I 2 Q

FIG. 1236.
Enoploteuthis leptura. Recent;

594 MOLLUSCA

SUB-KINGDOM VI

is situated in the hinder portion of the body and is partially enveloped by the
mantle. Among extinct Belemnites the internal shell consists of three parts :
a chambered cone (phragmocone), which is prolonged forwards on the dorsal
side into a delicate corneo- calcareous proostracum, and is inserted at the
posterior end into a finger-like calcareous piece called the guard (sheath or'
rostrum), (Fig. 1237, C).

Some living Cuttle-fishes have an elongated-oval, horny, feather-shaped
proostracum or "pen" (Fig. 1255), which is situated dorsally in a closed sac
of the mantle. It is sometimes extremely thin, and composed of conchyolin
or lime carbonate. The gladius or " cuttle-bone," as the shell is called when
calcified in some genera, retains a vestige of chambering at its posterior end,
but as a rule exhibits no indication of a phragmocone, properly speaking.

Many living Dibranchiates are gregarious, and swim in the open sea in
hordes ; others creep on the bottom or lead a separate existence along rocky
shores. They are extraordinarily active, voracious animals, and prey upon
mollusks, crustaceans, and fishes. A few species are esteemed as food by man.
In size Dibranchiates are extremely variable ; some forms are only 2 or 3 cm.
long, and others attain gigantic dimensions. Architeuthis, for example, reaches
a total length of 12 metres, the body being 2*5 long, and over 2 metres in
circumference. Its arms are thick as a man's leg, and the suckers sometimes
as large as ordinary coffee-cups.

Dibranchiates are divided into three sub-orders, as follows : — Belemnoidea,
Sepioidea, and Octopoda.

Sub-Order A. BELEMNOIDEA. (Phragmophora, Fischer.) l

Shell internal, chambered, and the septa traversed by a siphuncle ; conical or more
rarely spiral, and (with the exception of Spirula} terminating posteriorly in a calcareous
sheath or guard. Arms ten in number, provided with hooJclets. Trias to Recent.

Save for the genus Spirula, all forms belonging to this sub-order are extinct. Their
camerate shells, perforated by a siphuncle, betoken a kinship with Tetrabranchiates,
but there are decided differences both in shell-structure and function. Tetrabranchiates
have the shell always external, enclosing the body, but in the present group it is
enveloped by the soft parts. Direct connection between the Sepioidea and JBelemnoidea
is apparent, and although their shells differ in form and structure, yet a rudimentary
phragmocone persists in the former at the posterior end of the skeleton. This
rudiment is much more perfectly developed in Belosepia of the Tertiary, which is a
connecting link between Belemnoidea and Sepioidea. It is possible to explain the
entire internal shell of Spirula as homologous with the phragmocone of Belemnites.
It begins as a globular or inflated protoconch, which is constricted off from the first
camera, and is devoid of a cicatrix. The siphuncle originates as a caecal tube, and is
continued apicad as a prosiphon, the same as in Tetrabranchiates.

Family 1. Belemnitidae. de Blainville.

Shell composed of a conical camerate phragmocone, continued on the dorsal side as a
proostracum, and an elongated solid rostrum or guard. Arms ten in number, of equal
length, provided with hooklets. Ink-bag present. Trias to Eocene.

1 In addition to the principal literature, cited on pp. 502-505, see the following : — Crick, O. C., On
Coccoteuthis and Acanthoteuthis (Geol. Mag. [4], vol. III. (1896), p. 439, arid IV. (1897), p. 1).—
Huxley, T. H., and Pelseneer, P., Report on Spirula (Appendix Challenger Rep., Zoology, Part
LXXXII1.), 1895.

SUB-CLASS ii DIBRANCHIATA .v.»r>

This family, owing to its great diversity of forms and geological imjiortance, occu
foremost position among Belemnoidca, The shell may be cou-i-l. r. ,1 as the prototype oi th.it
in all Dibranchiates, since it lias all the component ji.-u-t.s l'ull\ .1. \ . loj,,-,), \\hi-reaa in other
groups some of these become atrophied.

The shell of Bdemnitcs (Fig. 1237) consists of three fundamental portions: (1) A
calcareous piece, usually much elongated, and of >ul>-ryliiniri<'.il, conoidal, or fusiform
This is called the guard (rostrum, osselct, gain<\ >'<•/« /'/••), and is excavated at its aut'iior
broad extremity into a conical cavity or alveolus. Within tin- alveolus is placed (2) the
phragvwcom. This consists of a conical series of chambers (loculi), the septa of which .in-
pierced at the ventral margin for the passage of the siphuncle. The phragmocone begin^ \s itli
a globular protoconch, and its last or anterior chamber is of comparatively large size. It i.s
invested with a thin proper wall (conotheca), which is prolonged forwards mi the <l<u>al >i«le
into a more or less calcined plate called (3) the proostracum. This last corresponds to the
"pen" of living cuttle-fishes. There is evidence that its anterior margin is convex, hut it i.s
so extremely thin that it is never perfectly preserved, and like the phragmocone, i> \\ anting
in by far the greater number of specimens.

Notwithstanding the fragmentary condition in which the proostracum invariably occurs,
it is possible to reconstruct its outlines from the peculiar conothecal striae, or markings of the
membranous substance with which it is invested. The conotheca is made up of three very
thin superimposed laminae, the outermost of which usually shows the markings alluded to
most distinctly (Fig. 1237, C). The conical surface of the phragmocone and proostraciun is
divided by Voltz into four principal regions radiating from the apex : A dorsal area, including
all the space between two straight lines called the asymptotes, which extend from the apex of
the cone as far as the aperture. This area occupies about one-fourth of the circumference, and
is marked with loop lines of growth convex toward the front. On either side of the dorsal
area and separated from it by the asymptotes is a lateral or hyperbolic area, each out-
occupying about one-eighth of the circumference, and covered with very obliquely arched
lines in a hyperbolic form. The ventral area is covered with numerous transverse striae, of
which there are many on each alveolar chamber, and they are closer together the nearer they
are to the apex of the phragmocone. The striae of the dorsal area are less numerous than
those of the rest of the shell, and usually less pronounced, being sometimes imperceptible.

"The guard of Belemnites consists of prismatic calcareous fibres, which are directed
perpendicularly to the surface, and radiate in all directions from an axial line, which is not
strictly central, but is somewhat nearer the ventral than the dorsal side. The growth of the
guard is effected by the deposition of successive conical layers or sheaths, which are secreted
over the entire surface, but are thickest behind, and become gradually attenuated in front.
The surface of the guard is smooth ; or may be wholly or partially granulated or wrinkled ;
or, again, may be marked with branched vascular impressions, which are especially con-
spicuous on the ventral side. In many cases a well-marked groove — the ventral furrow — runs
from the edge of the alveolus backwards on the ventral side, extending for a short distance
only, or reaching to the point of the guard (Fig. 1241, C}. The apical portion of the guard
often shows two symmetrical grooves (the dorso-lateral grooves) which diverge slightly and
become shallower as they extend forwards, and which mark the dorsal side of the shell "
(Nicholson).

As shown by vascular impressions on the rostrum, the shell of Belemnoids was completely
enveloped by the mantle. Natural casts of the animal occurring in the English Lias (Figs.
1237 B, 1250) exhibit an elongated form of body, contracted anteriorly, with a small head
surrounded by ten equal arms. An ink-sac is present, and the arms are provided with hooks.
The maximum size attained by Belemnitoids is between 2 and 2 '5 metres.

Aulacoceras, Hauer (Fig. 1238). Guard elongated, clavate, contracted anteriorly,
thickened in the posterior third, and pointed at the tip ; composed of concentric,
loosely superimposed lamellae. Each side marked by a deep broad lateral groove
reaching from the tip as far as the anterior alveolar margin. Phragmocone at least
twice as long as the rostrum, slowly increasing in width anteriorly, ornamented
externally with raised longitudinal lines, which are crossed on the dorsal side by a
transverse series, convex toward the front; closely resembling Orthoceras. Septa
rather distantly spaced ; siphuncle marginal, thin ; proostracurn unknown. Guards
of this genus are rare, but detached phragmocones not uncommon. Upper Alpine
Trias.

Atractites, Gumb. Like Aulacoceras, but guard large, smooth, and without lateral
furrows. Phragmocone either smooth, or with fine asymptotic lines, and dorsal area
marked with extremely fine growth-lines, convex toward the front. Guards and

596

MOLLUSCA

SUB-KINGDOM VI

phragmocones almost always occur detached. The former originally mistaken for
Orthoceratites, but are distinguished by their marginal siphuncle and characteristic
conothecal striae. [Hyatt regards both Aulacoceras and Atractites as descended from
Orthoceratites.] Upper Trias and Lias of the Alps.

Xiphoteuthis, Huxley. Lower Lias ; England.

Belemnites, Lister (Figs. 1237-1242). Name first applied by Agricola in 1546.
Guard dactyliform, subcylindrical, or conoidal, sometimes short and thick, sometimes

A, Vertical section of a Belemnite, the proostracum broken away
above the phragmocone. B, Bclemnites Brugierianus, Miller. Lower
Lias ; Channouth, England. Cast of complete individual. 1/3 (after
Huxley). C, Restoration of a Belemnite shell.

Abbreviations: R, Rostrum or "guard"; Ph, Phragmocone; Po,
Proostracum ; a, Apical line reaching from apex of guard to bottom of
alveolus (o) ; &, Impression of arms ; c, Camerae of phragmocone ; i, An-
terior end of proostracum ; o, Protoconch ; si, Siphuncle ; x, Ink-bag.

FIG. 1238.

Aulacoceras reticulatum, Hauer.
Upper Trias ; Rothelstein, near
Aussee, Austria. A, Guard and
phragmocone, 2/3. B, Guard, Vi-
C, Portion of phragmocone sliced
to show siphuncle and siphonal
funnels.

slender and much elongated ; retral portion tapering, submucronate, or obtusely
rounded. Owing to irregularity in secretion of calcite layers on the periphery of the
guard during growth, individuals belonging to the same species but of different ages
are apt to vary considerably in form. Such differences are well illustrated in B.
acuariuSj Schloth. The young are sometimes fusiform, but grow cylindrical or
conical with age. About 350 species are known, ranging from the Lower Lias to
summit of the Cretaceous; maximum from Middle Lias to Lower Cretaceous.

SUB-CLASS II

DIBRANCHIATA

51)7

Distribution world-wide ; most abundant in Europe, Asia, and North America. As

an index fossil of the Jura and Cretaceous,

this genus is scarcely less important tlmn h

Ammonites.

Sub-Genera : Pachyteutkis, Bayle (Fig. 1241, A).
Guard perfectly smooth. Confined to Lower Lias.
B. acutus, Mill.

Megateuthis, Bayle (Dactylotcuthis, Bayle ;
Paxillosi), (Fig. 1241, B). Apex of guard with
two or three usually short grooves. Middle Lias
to Lower Cretaceous. B. paxillosus, B. gigantcus,
Schloth. ; B. elongatus, Mill. ; B. subquadratus,
Roem., etc.

JBelemnopsis, Bayle (Hibolithes, Montf. ; Gastro-
coeli, Canaliculati, Hastati], (Fig. 1241, D, E).
Guard with deep and usually long ventral furrow
extending from alveolar margin toward the aju-x,
with or without dorso-lateral lines. Middle Jura
to Middle Cretaceous. B. canaliculatus, Schloth. ;
B. absolutus, Fisch. ; B. unicanaliculatus, Ziet. ;
B. minimus, Lister.

Fio. 1239.

Belemnites compressus. Lias ;
Guiulershofen, Alsace.
Phragmocone with well-pre-
served conotheca. a, Asymp-
totic line ; h, Hyperbolic
area ; v, Ventral area.

Fio. 1240.

Belemnites (Duvalia)
dilatatus, Blv. Neo-
coinian; Justithal,
Lake of Thun, Switzer-
land.

Fio. 1241.

A, J5. (Pachyteuthis) acutus, Miller. Lower
Lias; Lyme Begis, Dorsetshire. B, B. (Mega-
teuthis) pcmllosus, Schloth. Middle Lias ; M.-tzin-
gen, Wiirtemberg. C, B. (Pseudobelus) bipartitus,
Blv. Lower Cretaceous ; Castellane, Basses
Alpes. a, b, c, Dorsal and ventral aspects and
cross-section, 1/1- A •& (Belemnopsis) <•"
latus, Schloth. Inferior Oolite; Wurtembcrg.
E, B. (Belemnopsis) hastatus, Blv. Oxfordian ;
Dives, Calvados.

Pseudobelus, Montf. (Bipartiti), (Fig. 1241, (7). Guard thin, slender, with deep dorso-
lateral grooves, with or without ventral furrows. Upper Lias to Lower Cretaceous. B. exilis,
d'Orb. ; B. bipartitus, Blainv.

Actinocamax, Mill. (Gonioteuthis, Bayle), (Fig. 1242). Guard cylindrical, submucrpnate,
with short but very deep ventral furrow ; anterior end foliaceous, and very liable to dissolu-
tion. Phragmocone only very slightly inserted in the guard, the two portions usually
separated by an interval. Middle and Upper Cretaceous. B. subventricosus, Wahlb. ; B.
quadratics, Blainv.

Belemnitella, d'Orb. (Fig. 1243). Guard cylindrical, with short, deep ventral furrow
falling short of alveolar margin. Phragmocone inserted in guard. Vascular impressions
often beautifully preserved. Upper Cretaceous.

598

MOLLUSCA

S QB-KINGDOM VI

Diploconus, Zitt. (Fig. 1244). Guard short, obtusely conical, and having a con-
centric lamellar structure, not radial and fibrous. Phragmocone reaching nearly to
posterior end of guard. Tithonian.

Bayanoteuthis, Mun.-Chalm. Guard long, cylindrical, mucronate, with shallow
lateral grooves. Dorsal area roughened. Phragmocone very slender and long, oval in
section. Eocene. B. rugifer, Schloenb.

Vasseuria, Mun.-Chalm. Guard slender, elongated-conical, with three longitudinal
grooves extending from the apex. Alveolus over half as long as the guard.

FIG. 1242.

Belemnites (Actinocamax) quad-
ratus, Blv. sp. Upper Creta-
ceous ; Germany. A, Dorsal
view of guard with deformed
phragmocone projecting from
alveolus. B, Ventral aspect of
guard. C, Alveolus from above
(after Schluter).

FIG. 1244.

Diploconus belem-
nitoidea, Zittel. Ti-
thonian ; Stramberg.

FIG. 1243.

Belemnites (Belemnitella) mucronatus,
Schloth. Upper Cretaceous ; Drenstein-
furth, Westphalia. A, B, C, Ventral, dorsal,
and lateral aspects. 2/3.

FIG. 1245.

Beloptera belem-
nitoidea, Blv. Calcaire
Grossier; Paris Basin.
Ventral aspect.

Siphonal funnels extending from one septum to the next. Very rare in Eocene of
Pretagne.

Belemnosis, M. Edw. Very rare in English Eocene.

Beloptera, Blainv. (Fig. 1245). Guard short, composed of two cones placed with
their apices against one another and united by a central expansion which projects
outwardly on either side. Anterior cone with alveolus. Phragmocone unknown.
Eocene.

Belopterina, Mun.-Chalni. Like Beloptera, but without the lateral wing-like
expansiona Eocene.

Family 2. Belemnoteuthidae. Zittel.

Shell composed of a conical phragmocone and proostracum, the rostrum being reduced
to a thin calcareous investment of the phragmocone. Ten arms of nearly equal length,
each beset with a double row of hooks. Ink-sac present. Trias and Jura.

SUB-CLASS ii DIBRANCHIATA f,'.M)

Acanthoteuthis, Wagner and Miinst. (Belemnites, Qiu-n.-t. ]>.j'. ; Ostracoteuthis,

Acanthoteuthis speciosa,
Miinst. Eiclistadt. A, '••.

muuau. JHWUDUHJ.VI ^i, •. "* -^

Impression of shell, the '"•^2^^/^. ^~>£ f ^

proostracum accident-
ally bent sideways. B,
Proostracnm showi
septa and s
funnels. 2/g.

FIG. 1248.

Acanthoteuthis speciosa,
Miinst. Solenhofen. Pro-
ostracum. 2/3.

FIG. lJ4ii.

Amnthoteuthis speciosa, Munst. Lithographic
Slates ; Eiclistadt, Bavaria. Impression of arm*
and body. Va.

Zitt), (Figs. 1246-1248). Phragmocone with numerous
septa, and siplmncle having short siphonal funnels ;
enveloped externally in a thin granular calcareous layer
representing the guard. Surface of proostracum divisible
into a broad dorsal, and two narrow lateral areas which
are longitudinally striated and taper toward the front.
Dorsal area ornamented with fine parabolic and also
straight longitudinal lines ; anterior margin rounded.
An impression of the animal found in the Lithographic
Slates shows an ink-bag and ten powerful arms about
the head, which are beset with two rows of opposite,
horny, falciform booklets. Upper Jura.

Phragmoteuthis, Mojs. (Fig. 1249). Proostracum
twice as long as the conical phragmocone, with dorsal
area bounded by asymptotic lines, and two shorter
lateral areas; anterior margin of all areas rounded.
Phragmocone invested by a brownish layer represent-
ing the guard. Trias (Raibl Beds).

Belemnoteuthis, Pearce (Conoteuthis, d'Orb.), (Figs.

600

MOLLUSCA

SUB-KINGDOM VI

1250, 1251). Like Acanthoteuthis but smaller, and phragmocone not produced
into a long proostracum. Upper Callovian and Lower Cretaceous.

FIG. 1249.

A, Phragmoteuthis bisinuata,
Bronn. sp. Trias ; Eaibl, Car-
inthia. Ph, Phragmocone ; Po,
Proostracum; L, Lateral area
of proostracum; d, Ink-bag.
B, Booklets of arms, 1/1 (after
Suess).

FIG. 1250.

Belemnoteuthis antiqua,
Pearce. Oxford Clay ; Chris-
tian Malford , Wilts. A , Partly
restored specimen, 1/2- oc»
Eyes ; m, Mantle. Other
letters as in Fig. 1249. B,
Booklet, 4/j (after Mantell).

FIG. 1251.

Belemnoteuthis, Pearce sp. Oxford Clay ;
Gammelshausen, Wiirtemberg. A, C, .
Dorsal and ventral aspects. B, Septum
and siphuncle.

FIG. 1252.

Spindirostra Bellardii, Mich. sp. Mio-
cene ; Superga, near Turin, Italy. A,
Side view. B, Longitudinal section. R,
Guard ; Ph, Phragmocone. Vi (after
Munier-Chalmas).

Family 3. Spirulidae. Zittel.

Shell reduced to a chambered phragmocone coiled into a flat
spiral, the coils not in contact ; situated in posterior part of the
body, and the greater portion contained within the mantle. In
addition to the eight arms, two long tentacles without hooks are
placed between the third and fourth pairs. Pliocene and Kecent.

Spirulirostra, d'Orb. (Fig. 1252). Shell composed of a short
triangular pointed guard, which is excavated anteriorly for the
reception of the chambered phragmocone. The latter begins as
a spiral, but speedily becomes straight, and has septa pierced on
the concave ventral side by the marginal siphuncle. Only
one species. Upper Miocene of Turin.

Spirulirostrina, Canavari. Like the preceding, but guard
p, Prosiphon; s, siphuncle reduced to two small, lateral wing-like appendages. Neocene

offo-». \T n».;tlY> r<iiniv«oa\ o A JT o

FIG. 1253.

Spirula Peronii, Lam.
Recent ; Pacific. Longi-
tudinal section, 1/1- «> Pro-
toconch ; c, Caecal com-
mencement of siphuncle ;

after Munier-Chalmas).

of Sardinia.

Spirula, Lam. (Fig. 1253). Guard wanting. Chambered phragmocone enrolled

SUB-CLASS II

hllSKANCHIATA

001

with the ventral side coin •avi-, tin- coils not in contact, composed of nacreous substance ;
septa concave; protoconch globular. Sipliunrlr ventral and iiiarLfin.il in po.-itinn,
completed by siphonal funnels extending Ixitween the septa. Prosiphon present.
Recent ; inhabits tropical seas. [For description of the animal see " Zoology," Part
1 A XXIII., of Challenger Reports, 1895.]

Sub-Order B. SEPIOIDEA. Cuttle-fishes.

Shell internal, without differentiated phragmocone and guard, but consisting essenti-
ally of proost racum or "pen," which is either oval, or narrow and elongated. Arms ten
in n umber, provided with suckers or hooks. Ink-bag present.

Family 1. Sepiophoridae. Fischer.

Skeleton calcareous, elongated-oval, terminating posteriorly in a thickened mucro
which represents a rudimentary phragmocone and rostrum, and encloses a conical cavity.
Siphuncle wanting.

The thickened posterior mucro is a rudimentary structure probably corresponding
to the guard of Belemnoids, and
its conical cavity to the alveolus
Belosepia retains a vestigial
chambering but no siphuncle,
and in Sepia a recognisable
phragmocone is wholly wanting.

Belosepia, Voltz (Fig. 1254).
As a rule only the posterior
portion of the proostracum is
preserved. This ends in a bent
spine, which is thickened an-
teriorly, laterally expanded, and
contains near the apex a conical
alveolus. The latter showa on
the dorsal side incomplete traces
of septa, and a wide funnel-like
depression occupies the place of a
siphuncle. Eocene ; not uncom-
mon in Paris Basin.

Sepia, Lam. (Fig. 1255).
Proostracum of equal length
with the mantle, elongated-oval,
rounded anteriorly, thickened
posteriorly and terminating in a

short mucro. The latter contains
a conical alveolus. External walls

Fio. 1254.

Belosepia Blainvillei, Desh.
Eocene ; Auvers, near Paris,
of proostracum consisting of tWO A> Posterior end of shell,
, . , , , ventral aspect. ]i, Same from

brittle calcareous laminae, the side (after Deshayes).

In-

Fiu. 1255.

Septa offlcinalis, Linn. Recent.
Ventral view of shell. A, Cal-
careous lamellae of proostracum.
li, Position of rudimentary ph rag-
mocone in front of mucro, 2/3.

separated by a horny layer,
ternally with a mass of extremely fine parallel calcareous lamellae, increasing in
thickness anteriorly ; the lamellae separated from one another by minute vertical
rods, thus producing a spongy texture. The familiar cuttle-bone of commerce or
ossa Sepiae, is the pen of Sepia officinalis, Linn., and is found in great quantities
along the coast of certain countries. Several Tertiary species known.

602

MOLLUSCA

SUB-KINGDOM VI

Family 2. Chondrophoridae. Fischer.

Proostracum much elongated, thin, composed of conchiolin or of alternating layers of
calcareous and horny matter, thickened posteriorly, and without conical alveolar cavity.
Jura to Recent.

Goccoteuthis, Owen (Trachyteuthis, v. Meyer (Fig. 1256). Proostracum elongated-
oval, composed of calcareous and horny laminae, rounded posteriorly or with but
slightly projecting mucro ; external surface roughly granulated, and marked by lines
diverging from the apex. These lines limit the boundaries of two wing-like
expansions projecting from the sides of the elongated median portion. Impressions of
the body and arms occasionally found in the Lithographic Slates of Bavaria. Upper
Jura.

Leptoteuthis, v. Meyer. Proostracum very large, thin, narrowing posteriorly, and
composed of several layers of calcareous and horny layers. Median area ornamented

FIG. 1256.

Coccoteuthis hastiformis, Eiipp.
sp. Lithographic Slates ; Eich-
stadt, Bavaria.

FIG. 1257.

Beloteuthis Schvebleri, Quenst.
Upper Lias ; Holzmaden, Wiir-
teniberg. 1/2 (after Quenstedt).

FIG. 1258.

Geoteuthis Bollensis, Zieten.
Upper Lias ; Holzmaden, Wiirtem-
berg. Shows ink-bag and cono-
thecal striae. V-

with fine undulating transverse striae, convex toward the front, and separated from the
lateral areas by longitudinal lines diverging from the apex. Lateral areas marked
with oblique inwardly directed lines, and bordered by lateral expansions which are
widest posteriorly. Upper Jura of Southern Germany. L. gigas, v. Meyer.

Geoteuthis, Miinst. (Fig. 1258). Proostracum composed of thin alternating horny
and calcareous layers, widest in front, rounded posteriorly. Median area divided into
halves by a longitudinal line, and bounded on either side by lateral areas with
hyperbolic striae. Ink-bag frequently preserved, the contents transformed into a jet-like
substance. It is possible to dissolve the carbonaceous particles so as to prepare a wash
resembling India ink. Upper Lias of Germany, France, and England.

Beloteuthis, Miinst. (Fig. 1257). Proostracum very thin, elongated, feather-shaped,

SUB-CLASS II

DIBRANCHIATA

broadly rounded posteriorly, pointed in front, traversed by a median longitudinal
keel. Upper Lias of Wiirteinberg.

Teuthopsis, DesL Lias. Celaeno, Mtinst. Up].« T

Jura. Phylloteuthis, Meek and Hayden ; Actinosepia, rf ^*G

Whiteaves. Cretaceous.

Plesioteuthis, Wagner (Fig. 1259). Prooetracum v. -i y '
thin, long, narrow, lanceolate, pointed posteriorly, rounded t
in front, with a median longitudinal keel and a raised
line along each of the lateral edges. Very abundant in
Lithographic Slates, and impressions of the body and head
not uncommon. Also found in Cretaceous of Maestricht
and Syria.

Sub-Order C. OCTOPODA.

Body without internal shell, and only the female of
Argonauta secreting a single-chambered external shell. The
two tentacles are not present, and the eight arms bear sessile
suckers without horny rims. Eye relatively small, without
sphincter-like lid. Body short and rounded, usually without
Jin-like appendages.

The majority of genera belonging here are naked and
therefore without fossil representatives. The small male
of Argonauta, Linn., is without a shell, but the large
female bears a delicate, boat-shaped, spiral shell which is
secreted partly by the mantle, and partly by two fin-like
expansions of the dorsal arms. Outer surface of shell
ornamented by folds and tubercles, and two nodose ventral
keels are present. Late Tertiary and Kecent.

Fio. 1259.
Plesioteuthis proco, RUi

Vertical Range of the Dibranchiata.

As compared with Tetrabranchiates, the Dibranchiata
are of subordinate geological importance. Their entire
organisation renders them less well adapted for preserva-
tion in the fossil state, and accordingly we shall never be
able to form even an approximate idea of their importance

in their contemporaneous faunae. The earliest representa- rusiouutms pnsca, Kupp. up.

tive of Belemnoidea appears in the Trias (Aulacoceras), Lithographic Slates • Eichs'uidt!

, ,, « • .7 ...... . T. _. . '7 A, Impression of annual showing

and the Sepioidea are initiated in the Lias. From what arms and ink-bag. B, Shell, V*

group Dibranchiates are descended, whether from the

Tetrabranchiates or from primitive naked ancestors, we have at present no certain
means for determining. They appear suddenly in a high state of development ; but a
still more remarkable fact is the swift culmination and decline of the group of
Belemnoids. In place of the small number of forms met with in the Trias, we find
even in the Lias, as well as other divisions of the Jura and Lower Cretaceous, a rich
and varied Belemnite fauna. At the close of the Cretaceous only two genera,
Belemnitella and Actinocamax, persist in relatively large numbers, and although a few
antiquated relics of the same stock hold over into the Eocene, their very rarity
demonstrates waning vitality. The sole living representative of Belemnoids is the
genus Spirula.

In all probability the Sepioidea are descended from Belenmoids. Belosepia of the
Tertiary has tolerably distinct indications of a phragmocone, but in Sepia proper this

604

MOLLUSCA

SUB-KINGDOM VI

structure is reduced to the merest rudiment. Jurassic Chondrophoridae approximate
closely to recent members of the same family. All the evidence at our disposal
justifies the conclusion that Mesozoic Cuttle-fishes possessed an essentially similar
organisation to that of recent forms.

[The rendering into English of the original text for the chapters on Mollusca, exclusive
only of the Dibranchiates (Grundzuge, pp. 250-435), was performed by Dr. John C. Merriam,
Professor of Palaeontology in the University of California. His careful translation greatly
facilitated the labours of Professors Dall, Pilsbry, and Hyatt in their revision of the several
groups accredited to them. — TRANS.]

Restoration of MeganRura Monyi Brongt.
Brongniart). See page (584.

FIG. 1260.
Carboniferous ; Cornmentry.

i/6 natural size (after Charles

Sub-Kingdom VII. ARTHROPOD A. (ARTICULATES.)

Heteronomously segmented animals with, typically, a pair of appendages to each
somite of the body ; the whole enclosed in a chitinous segmented exoskeleton, the joint-
ing of which extends to the appendages.

In the Arthropoda the segments are unequally developed, and the
appendages, primitively locomotor in function, may be modified on one or
more somites to subserve special functions, such as the seizure and comminu-
tion of food, respiration, sensation, copulation, oviposition, fixation, etc.
These modifications of the appendages and the more or less complete union
of the segments into groups may result in the differentiation of three distinct
regions : head, thorax, and abdomen. Of these regions the head is concerned
largely in sensation and feeding, the thorax is chiefly locomotor in function,
and the abdomen frequently defensive.

The brain lies above and in front of the oesophagus, and consists of a
fusion of several pairs of ganglia. The rest of the central nervous system con-
sists of a chain of ganglia lying in pairs on the ventral surface, with typically
a pair in each somite. Not infrequently there is a more or less extensive con-
centration or fusion of these ventral ganglia. The eyes may be simple,
aggregate, or compound, with in some cases an inversion of the retinal layer.

Respiration in the smaller forms is by the general surface of the body,
whereas in the larger certain regions become specialised for this purpose.
When respiratory outgrowths protrude from the body wall they are known
as gills or branchiae; when invaginated they are termed lungs if they be
lamellar in arrangement, or tracheae if they consist of fine tubes ramifying
through the tissues.

Excretion is effected either by "segmental organs" (true nephridia)
which open at the inner end into the true body cavity (coelom) and at the
other to the exterior, or by diverticula developed at the hinder end of the
alimentary canal. The nephridia when present occur in only a few segments
of the body. The diverticula of the alimentary canal (Malpighian tubes) are of
two kinds — one developed from the mesenteron, the other from the procto-
derm. In all Arthropods the ducts of the reproductive organs are appar-
ently modified nephridia, and the organs themselves consist of gonads
developed from the coelomic walls. The circulation depends upon a dorsal
heart enclosed in a vascular pericardial sac, and metameric blood-vessels
terminating in " lacunar " spaces.

Arthropods are divisible into three groups or sub-phyla, distinguished
according to the nature of the respiratory organs, segmentation of the body,

606 ARTHROPOD A SUB-KINGDOM vn

and structure of the appendages as follows : — EranchiaJa, Miiriopoda, and
Insecta. These are in turn divided into several classes, all of which have
fossTl representatives. As to the origin of the phylum, Palaeontology affords
no certain evidence. The entire organisation of Arthropods indicates a close
relationship with Vermes, and especially with the group of Annelid Worms ;
nevertheless, the differentiation of the Arthropod type must have antedated
the Cambrian, since several orders of Crustacea are encountered in the oldest
fossiliferous rocks which are almost as widely divergent from the supposed
ancestral form as many recent forms. The relatively late appearance of
Myriopods, which are the most worm-like of all Articulates, may be accounted
for by their terrestrial habitat and destructibility of their body parts.

SUB-PHYLUM A. BRANCHIATA.

Arthropods breathing by means of gills (or lungs or tracheae modified from gills)
developed always in connection with the appendages. Head and thorax rarely distinct,
but usually more or less completely united in a cephalothorax. The genital ducts
open to the exterior near the middle of the body, and true nephridia usually occur.
Malpighian tubes, when present, are derived from the mesenteron. Anterior append-
ages all multiarticulate, the basal joints of one or more pairs serving as organs of
manducation.

The branchiate Arthropods include two classes : Crustacea and Acerata.

Class 1. CRUSTACEA.1

Arthropods of usually aquatic habitat, and breathing by gills (exceptionally
through the general body surface) ; with one or two pairs of appendages (antennae) in
front of the mouth, the first of which is purely sensory, and several pairs of post-oral
appendages, some of which are modified into organs of mastication. Appendages with
typically a basal joint (protopodite) giving rise to two or three branches.

The segmentation of the body is distinct in all except certain parasitic
forms, where it is lost in the adult stage through degeneration. Usually the
demarcation between head and thorax is obscure, and the anterior region of
the body consists of a cephalothorax, the number of whose segments varies
within wide limits ; this being in sharp contrast to the Acerata, where the
segments are constantly six in number. The cephalothorax is frequently
covered by a chitinous shell or carapace, developed from the dorsal portion of

1 Literature :
Brongniart, A., and Demarest, A.-G., Histoire naturelle des Crustaces fossiles sous les rapports

zoologiques et geologiques. Paris, 1822. .

Milne- JZdwards, H., Histoire naturelle des Crustaces. 3 vols. Paris, 1834-40.
Woodward, H., and Salter, J. W., Catalogue and Chart of Fossil Crustacea. London, 1865.
Woodward, H., A Catalogue of British Fossil Crustacea. London, 1877.
Gferstaecker, A., Crustacea, in vol. V. of Bronn's Classen und Ordnungen des Thierreichs. Part 1

(Cirripedia, Copepoda, Branchiopoda, Poecilopoda, Trilobita), Leipsic, 1866-79; Part 2

(Isopoda to Decapoda), 1881-94.
Vogdes, A. W., A Catalogue of North American Palaeozoic Crustacea confined to the non-trilobitic

Genera and Species (Ann. N.Y. Acad. Sci., vol. V.), 1889.
Grobben, K., Genealogy and Classification of the Crustacea (Sitzungsber. Akad. Wisseusch. Wieu

Bd. CL, Heft 2), 1892. Translated in Ann. and Mag. Nat. Hist. [6], vol. XI. pp. 440-473.
Kingsley, J. S.', The Classification of the Arthropoda (Amer. Nat., vol. XXVIII. pp. 118, 220)

1894. Reprinted in Tufts College Studies, No. 1, 1894, with copious bibliography.

CLASS I CRUSTACEA 607

the second and third segments, and is frequently strengthened by deposits of
carbonate and phosphate of lime. Although the carapace is usually a single
piece, yet in some forms (Estheriiform Phyllopods and Ostracods) it may
consist of two lateral valves, which enclose the body like a Pelecypod shell ;
or of four parts, as in certain I'hiiU<n-<irida ; or a^ain (t'irripedia) of a number
of calcareous plates. The abdomen is usually well developed ;md its seg-
ments are free, but occasionally it becomes greatly reduced, as in certain
Entomostraca.

The total number of body somites varies within wide limits in the
Entomostraca and Trilobites, but in the Malacosiraca they are almost constantly
twenty-one, ranging slightly higher in the Phi/llocarida, and falling shorter in
the parasitic Laemodipoda.

In all living Crustacea there are two pairs of antennae, although in some
forms (Apus, Oniscids) one or the other pair may become greatly reduced.
In the Trilobites, on the other hand, but a single pair has been discovered.
The appendages are exceedingly variable in form, according as they serve
for sensation, comminution of food ("mouth parts"), locomotion, respiration,
capture of prey, or copulation. The primitive form was a lamellar appendage
like those found in the thoracic region of Phyllopods, but the typical foot is
usually stated to consist of a basal portion (protopodite) of one or two joints,
and a distal portion made up of an inner (endopodite) and a lateral branch
(exopodite). In many cases the exopodite becomes greatly modified or even
entirely atrophied in the adult.

Most of the lower Crustacea escape from the egg in a larval condition
known as the nauplius stage. In the nauplius the body is unsegmented, there
is but a single median eye, and but three pairs of appendages, correspond-
ing to the two pairs of antennae and mandibles of the adult. The nauplius
gradually becomes metamorphosed into the adult Crustacean, the changes being
accomplished by several moults of the external chitinous crust. In the higher
Crustacea this free-swimming nauplius stage is omitted, the animal already
having the form of the adult as it escapes from the egg. The Decapods have
a larval stage known as the zoea, in which seven pairs of appendages and a
segmented abdomen are present. These larval stages are of great value in
determining relationships, but most modern authorities regard them as adaptive
rather than ancestral ; or, in other words, it is not believed that existing
Crustacea are descended from an ancestral form resembling the nauplius.

Two sub-classes are recognised : — Trilobita and Eucrustacea. The term
Entomostraca is here used in a collective sense to distinguish the lower orders
of Eucrustacea from the highest, or Malacostraca.

Sub-Class 1. TRILOBITA. Trilobites.1

Marine Crustacea, with a variable number of metameres ; body covered with a
hard dorsal shield or crust, longitudinally trilobate from the defined axis and pleura;

1 Literature : A. General Works.

Brongniart, A., Histoire naturelle des Crustaces fossiles. 1882. — Dolman, J. W., Ueber die
Palaeaden oder die sogenannten Trilobiten. 1828. — Green, J., Monograph of the Trilobites of
North America, with Coloured Models of the Species. 1832. — Burmeister, H., Die Organisation
der Trilobiten. I8±3.—Beyrich, £., Ueber einige bohmische Trilobiten. Berlin, 1845-46.— Corda,
J. C., and Hawle, J., Prodrom einer Monographic der bohmischen Trilobiten. Prag. 1847. — Hall,
J., Palaeontology of New York, vols. I.-IIT. 1847-59. — Barrande, J., Systeme Siluru-n du

608 ARTHROPODA

SUB-KINGDOM VII

cephalon, thorax, and abdomen distinct. Cephalon covered with a shield composed of
a primitively pentamerous middle piece, the cranidium, and two side pieces, or free

Centre de la Boheme. Part I. 1852; Supplement, 1872. — Angelin, N. P., Palaeontologia
Scandinavica. Part 1. Crustacea formationis transitionis. 1854. — Nieszkowski, J., Versuch einer
Monographic der in den silurischen Schichten der Ostseeprovinzen vorkommenden Trilobiten.
1857. — Hojfmann, E., Sammtliche bis jetzt bekanute Trilobiten Russlands. (Verliandl. Mineral.
Gesellsch. St. Petersburg), 1857-58. — Salter, J. W., A Monograph of British Trilobites (Palaeonto-
graphical Society), 1864. — Idem and Woodivard, H., ibid. 1867-84. — Schmidt, F., Revision der
ostbaltischen silurischen Trilobiten (Mem. Acad. Imp. St. Petersburg, vol. XXX., No. 1), 1882.—
Brdgger, W. C., Die silurischen Etagen 2 und 3 in Kristianagebiet und auf Eker. 1882. — Holm,
G., De Svenske Arterna af Trilobitslagtet Illaenus (Bihang till K. Svensk. Vetensk. Akad. Handl.,
vol. VII., No. 3), 1882,—Mattheiv, G. F., Illustrations of the Fauna of the St. John's Group.
1882-93. — Woodward, H., Monograph of the British Carboniferous Trilobites (Palaeontographical
Society), 1883.— Hall, J., and Clarke, J. M., Palaeontology of New York, vol. VII., 1888.— Walcott,
d. D., The Fauna of the Lower Cambrian or Olenellus Zone (10th Ann. Kept. U.S. Geol. Survey), 1890.

B. Structure and Appendages.

Burmeister, H., Vide ante, 1843. — Billings, E., Notes on some Specimens of Lower Silurian
Trilobites (Quar. Journ. Geol. Soc., vol. XXVI.), 1870.— Woodward, H., Note on the Palpus and
other Appendages of Asaphus from the Trenton Limestone in the British Museum (Quar. Journ.
Geol. Soc., vol. XXVI.), 1870.— Walcott, C. D., Preliminary Notice of the Discovery of the Natatory
and Branchial Appendages of Trilobites (28th Kept. N.Y. State Mus. Nat. Hist), 1875.— The
Trilobite ; New and Old Evidence relating to its Organization (Bull. Mus. Comp. Zoology, vol.
VIII.), 1881.— Novak, 0., Studien an Hypostomen bohrnischen Trilobiten (Sitzungsber. bohm.
Geselssch. Wissensch.), Jahrg. 1879, 1886. — Clarke, J. M., The Structure and Development of the
Visual Area in the Trilobite Phacops rana Green (Journ. Morphology, vol. II.), 1888. — Matthew,
W. D., On Antennae and other Appendages of Triarthrus beckii (Amer. Journ. Sci. [3], vol. XLVL),
1893.— Beecher, C. E., On the Thoracic Legs of Triarthrus (Amer. Journ. Sci. [3], vol. XLVI.),
1893. — On the Mode of Occurrence, and the Structure and Development of Triarthrus becki
(American Geologist, vol. XIII.), 1894. — The Appendages of the Pygidium of Triarthrus (Amer.
Journ. Sci. [3], vol. XL VII.), 1894.— Further Observations on the Ventral Structure of Triarthrus
(Amer. Geologist, vol. XV.), 1895.— The Morphology of Triarthrus (Amer. Jouru. Sci. [4], vol. I.),
1896. — Structure and Appendages of Trinucleus, ibid. 1895.

C. Ontogeny.

Barrande, J., Vide ante, 1852. —Beecher, C. E., The Larval Stages of Trilobites (Amer.
Geologist, vol. XVI.), 1895. — Mattheiv, G. F., Sur le developpment des premiers Trilobites (Ann.
Soc. Roy. Mai. de Belgique, vol. XXIII.), 1889.— Vide ante, 1882-93.

D. Systematic Position.

Zittel, K. A., Handbuch der Palaeontologie, Bd. II., 1881-85.— Grundzuge der Palaeontologie,
1895. — Lang, A., Text-book of Comparative Anatomy. English Translation by H. M. and M.
Bernard. 1891. — Kingsley, J. S., The Classification of the Arthropoda (Amer. Naturalist, vol.
XXVIII.), 1894.— Bernard, H. M., The Systematic Position of the Trilobites (Quar. Journ. Geol.
Soc., vols. L., LI.), 1894-95.— The Zoological Position of the Trilobites (Science Progress, vol. IV.),
1895. — Woodward, H., Some Points in the Life-History of the Crustacea in Early Palaeozoic Times
(Quar. Journ. Geol. Soc., vol. LI.), 1895. — Haeckel, E., Systematische Phylogenie der wirbellosen
Thiere (Invertebrata), 1896.— Beecher, C. E., Outline of a Natural Classification of the Trilobites
(Amer. Jouru. Sci. [4], vol. III.), 1897. — Pompeckj, J. F., Ueber Calymmene, Brongniart (Neues
Jahrb., Bd. I.), 1898.

E. Classification.

Barrande, J., Vide ante, 1852.— Beecher, C. E., ante, 1897 .—Brongniart, A., ante, 1822.— Bur-
meister, H., ante, 1843.— Corda, A. J. C., and Hawle, J., ante, 1847.— Haeckel, E., ante, 1896.—
Dalman, J. W., Om Palaeaderna eller de sa kallade Trilobiterna. Stockholm, 1826.— Milne-
Edivards, H., Histoire naturelle des Crustaces. 1834-40. — Quenstedt, F. A., Beitrage zur Kennt-
niss der Trilobiten (Wiegmann's Archiv. fiLr Naturgesch., vol. III.), 1837. — JEmmrich, H. F., De
Trilobitis. Dissertation. 1839.— Zur Naturgeschichte der Trilobiten, 1844.— Goldfuss, A., Systema-
tische Ueberschicht der Trilobiten mid Beschreibung einiger neuen Arteu derselben (Neues Jahrb.
fur Mineral.), 1843. — M'Coy, F., On the Classification of some British Fossil Crustacea, with
Notices of new Forms in the University Collection at Cambridge (Ann. Mag. Nat. Hist. [2], vol.
IV.), 1849.— Chapman, E. J., Some Remarks on the Classification of the Trilobites as influenced
by Stratigraphic Relations : with Outlines of a new Grouping of these Forms (Trans. Roy. Soc.
Canada, vol. VII.), 1889. — Reed, F. R. C., Notes on the Evolution of the Genus Cheirurus (Geol.
Mag. [4], vol. IV.), 1896.— Blind Trilobites (ibid. vol. V.), 1898.
, F. Bibliography.

Vogdes, A. W., A Classed and Annotated Bibliography of the Palaeozoic Crustacea (Cal. Acad.
Sci. Occas. Papers, IV.), 1893. Supplement in Proc. Cal. Acad. vol. V., 1895. See also references
under Crustacea.

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miller li/> /tri'fi-nf. >'/»/// /7r.< ,,j tin- ///»//•!/.*• /,/«,/w,/, ///«,// „//, another,
ininiiii'r jri'iu ttrn in ttn utii-iiiii-. jiH/t,iiiii<iii tegtienU /-.//-/.//i/r /// //»/////»..

A; /"/'Mi (I Caudal *///»•///. „•/// .*•;////'•«/>-, Ilinnn-ir a,,,/ /////A,////'/////, /•»//•/•// " /
jnintnl lii-iiimmx limits. All /////As //«/v //»•//• »•/,./•»// ///////Vs /<•/•//<//«/ gnafk

^ich become organs of manducation //// ////• ///•////. /,Vx/*//-»////»// ////"/>////<///<// ////// ////
branchial fringet on the exopodif'*. /i»i-'ln/nnrnf j>r<><-<'n/iit<t //•"/// " y//-/i/»i/<// ///!//»/>•
/O?T», the protaspis. A// the progressive <n/<//t/<u/ <>f *,/,„, /</.< </f tuceesnn ///».////>•.

The Trilobites constitute a group of extinct marine animals, am!
related to the stock of the higher modern Ci'n*1<i<;,i • they art- thcreforr to IP
considered as very primitive Crustaceans. The sub-class had its origin in JHL--
Cambrian times. Trilobite remains are very abundant in the oldest known
fossiliferous strata, the Cambrian, where they exceed in number and div«-i>itv
all other forms of animal life. They continue to be very plentiful in tin-
Ordovician and Silurian, but decline in the Devonian, and the few last sur-
vivors are found in the Carboniferous and Permian. Probably there havr
been more than two thousand species described, distributed among nearly t\\<>
hundred genera. These numbers give an idea of the amount of differentiation
and specialisation attained by Trilobites during Palaeozoic times.

Carapace. — Trilobites were covered or protected on the dorsal side by a
hard crust or shield, which is the only portion commonly preserved. Their
remains are therefore readily recognisable by the form and structure of this
shield. It is divided longitudinally by two dorsal furrows, or grooves, into
three portions or regions, and on this account the name Trilobite was first
given. The central part forms the axis of the animal, and contained tin-
principal organs, as the viscera, heart, and chain of ganglia. Transversely tin-
shield is divided into (a) a head portion called the cephalon ; (li) a series of
joints or segments, forming the thorax; and (c) a tail-piece or pygidium,
forming the abdomen.

The test seldom exceeds one millimetre in thickness, and consists of thin
laminae of carbonaceous and phosphatic compounds of calcium, some of which
were originally chitinous substances. The laminae are frequently traversed
by minute pores, which give a punctate appearance to the test, and are some-
times large, as in H(ninilt>n<>fiis and related forms.

The carapace is somewhat arched or convex, generally elongate-oval in
form, and rounded at both ends. The length is almost invariably greater
than the width. Very often the same species shows a broad form. M \\< !!
as a relatively larger, nan-own- one. The former was considered l>y
Barrande as representing the female, and the latter the male individual. Tin-
carapace is often ornamented with spines, teeth, and knobs. These may be of
the nature of surface ornaments, or in the case of spines, may be produced by
growths from the genal angles, the ends of the segments of the thorax and
pygidium, or the spiniform extension of the pygidial termination.

The carapace does not often terminate at the margin as a simple lamellar

plate, but is turned under, and forms a reflexed margin, or i/nuHm-i, which i-

parallel to the outer edge, but is separated from the upper surface by a narrow .

partially included space. This produces the hollow spines from the ends of

VOL. 1 2 B

610

ARTHEOPODA

SUB-KINGDOM VII

the segments, the genal angles, and the pygidium. In rare instances, the
spines are solid.

The axis, or middle part, is defined by two longitudinal dorsal furrows
extending the whole length of the thorax, and also over more or less of the
cephalon and pygidium.

The pleura are the two lateral areas on each side of the axis. Thus, there
are pleural cephalic, thoracic, and pygidial regions. The name pleuron or
pleura is especially applied to the extensions from the axial portion of each
free segment.

The Cephalon. — The cephalon, or cephalic shield (Fig. 1261) includes all
that part of the carapace in front of the thorax. It comprises the hypostoma,

epistoma, the free cheeks bearing
the eyes, the fixed cheeks, and the
glabella ; it is generally semicircular
in form, and is joined along its
posterior margin to the thorax.
The postero-lateral margins, or genal
angles, are frequently drawn out
into spines. Usually there is an
occipital furrow extending across
the cephalon parallel to the posterior
margin, and defining the occipital
ring or segment.

The glabella is the axial portion
of the cephalon, and is defined by
the primary dorsal furrows (Fig.
1261). It shows typically three
oblique or transverse furrows in
addition to the occipital ring, mark-
ing the limits of the original five consolidated segments, and corresponding to
the paired appendages of the ventral side. Sometimes the positions of the
muscular fulcra are also indicated on the dorsal surface, by short furrows, or
by shallow pits. The glabella may constitute nearly the whole of the cephalon,
as in Deiphon or Aeglina, or it may be narrow, as in Harpes, and Eurycare. In
some cases it does not extend over half the length of the cephalon, as in Harpes
and Arethusina, but it may extend to the frontal border, as in Placoparia or
Calymmene, or even beyond, as in Phacops, Ampyx, and Conolichas. The entire
portion of the glabella which lies in front of the anterior lateral furrows, and
which is often somewhat enlarged laterally, is called the frontal lobe. At
times the limitation between the glabella and fixed cheeks is scarcely defined,
as in Illaenus and Dipleura. Most frequently, however, three pairs of grooves
can be distinguished in front of the neck furrow, marking the pentamerous
division of the glabella and the five pairs of appendages attached to the
cephalon. Sometimes the lateral furrows are continuous across the glabella,
or again, they may be directed obliquely (Triarlhrus), or even form longi-
tudinal grooves (Conolichas).

The hypostoma, or labrum, is homologous to the upper lip of other
Crustaceans, and consists of a separate plate attached by an articulating
surface or line to the reflexed border of the cephalic shield (Figs. 1262,
1265, B).

Cephalon of Dalmanites Htiusmanni,
Brongt. sp. Devonian ; Bohemia.
I, Limb or border ; sin, Marginal
furrow ; a, Genal spines ; gl, Glabella ;
If, Frontal lobe; fl-P, Side lobes;
1-3, Side furrows of glabella ; so, Neck
furrow ; a, Neck ring ; @, Facial
suture ; oc, Visual surface of the eyes ;
P, Palpebral lobe.

BUB-CLAS8 I

TlMl.nlilTA

to which they are
They may occupy

/ •. /.'. '',

•!•• ami fri'i,'

(.•ifl-r Nnvak). /;/;, Ant.M-i. Mi.hlle

furrow; !•:, Posterior furrow of tin- ini'l'll<- \»>r-

tion ; /', I'o.strrinr edf ; >J, Pot-
ti-riur win;,'.1

In front of the hypostoma is a rostral area sometimes partly ..,-« -upird Ky
;i separate plate.

The fixed (-lurks are lateral e\ten>ion> from the ^laln-ll
firmly joined, forming tin- mitral portion of tin- rrphalon.
more than two-thirds of the cephalon, as
in Conocoryphe, or become greatly reduced,
as in Ann /thus, 7,//7/r/s, and J'r<-ln.<. The
'•/•n it/i// ii nt, consists of the glabella and tin-
fixed cheeks.

The free cheeks carry the compound
eyes, and are separated from the cranidium
by a suture. They may form (a) a con-
tinuous ventral plate, as in 7A/ /•/«.<.
./V//W//S, TrinHclcus, etc.; they may in-
clude (b) a greater or lesser portion of
the dorsal surface, being either entirely separated by the cranidium, or
(c) meeting and (d) sometimes coalescing in front. They are widely separated
in Ptychopa/Ha, in juxtaposition in Asaphus, and continuous in Dalmanites.

The iff mi I angles are the posterior lateral angles of the cephalon. They
may be rounded, as in Illaenus, angular, as in Bronteus, or spiniform, as in
Ti-i a in-lt' us and Dalmanites. They belong either to the fixed cheeks, as in
Dalmanites, or to the free cheeks, as in Illaenus, Bronteus, and Proetus.

The character of the cheeks is especially influenced by the facial
sutures separating the free cheeks from the rest of the cephalon. They
appear as sharply defined lines beginning either at the posterior margin, or
near the genal angles, or on the lateral margins, and extend to the eyes,
thence around the inner margin of the visual areas, then turn anteriorly, and
either unite in passing around the front of the glabella or remain separate, in
which case the sutures terminate in the anterior margin. The position of the
facial sutures thus determines the relative size of the fixed and free cheeks.
After the death of the animal, or after moulting, the cephalic shield frequently
fell into pieces, dividing along these sutures.

In most Trilobites, the existence of eyes has been demonstrated, though
they appear absent altogether in some genera (Conocoryphe, Agnostus), and are
so imperfectly shown in others that for a long time they remained unrecognised
(Agraulus, Sao, Ellipsocephalns, etc.). The eyes are compound, and are elevated
above the free cheeks. The adjoining area of the fixed cheeks is also drawn
upwards, thus forming the palpebral lobe. The visual areas of the eyes are
borne by the free cheeks. The shape of this area is extremely variable, but
together with the palpebral lobe it generally forms a truncated, conical, or
semilunar elevation, of which the laterally directed, convex side is occupied
by the visual area (Phacops, Asaphus). It may likewise have a circular or oval
form, and very little convexity above the general surface. The eyes may be
quite small, as in J^in-riiiiii-ini and T/-///H /•<>,•>•/>//, ilns ; large and prominent.
Phacops, Dalmanites, and Proetus; or very large, as in ./"//V/<i/, in some species
of which nearly the entire area of the free cheeks is faceted, and the visual
surface extends around the entire outer borders of the cephalon. In many of
the primitive genera the eyes are situated at the distal ends of raised lines, or
eye lines, extending outward from near the forward end of the glabella.

As regards their structure, the compound eyes of Trilobites are recognised

612 ARTHEOPODA SUB-KINGDOM vn

as of two kinds. In the first, the holochroal, the visual area is covered with a
continuous horny integument, or cornea, which is either smooth and externally
gives no idea of its compound nature, or granular, on account of the facets
beneath. The lenses of the ommatidia are often visible by translucence. The
second type of structure, the schizochroal, is confined to the single family
Phacopidae. In this, the visual area is made up of small, round, or polygonal
openings for the separate facets of the cornea, between which is an interstitial
test or sclera. The size of the facets varies from more than 0'5 mm. in some
of the Phacopidae^ to from 6-14 in the width of 1 mm. in other Trilobites.
The number and arrangement of the facets also vary greatly according to the
genus. Trimerocephahis Volbortlii shows only 14 facets, while species of Pliac<>i>*
may possess 'from 200-300, and Dalinanites Hausmanni has 600. Among the
holochroal eyes, the number of facets is much greater ; in Bronteus palifer it is
estimated at 4000, in Asaphus nobilis, and in Eemopleurides radians as high as
15,000. Usually the facets are arranged in regular, alternating, vertical rows,
or quincuncially.

Certain genera show visual organs of an entirely different type, which can
be best regarded as simple eyes, and correlated with the ocelli of many Crus-
taceans. Thus, the genus Harpes, and some species of Trinudeus present from
one to three simple elevations or granules on the fixed cheeks, at the ends of
eye-lines, while the ordinary compound eyes on the free cheeks are absent.

The Thorax. — In contrast to the undivided cranidium, the thorax consists
of a series of short, transverse, articulating segments, which vary in number
with the genus. Every thoracic segment is divided by the dorsal furrows
into a middle portion (axis, tergum) and two lateral divisions (pleura, epimera).
The axial portions are firmly arichylosed with the pleura, and are generally
strongly convex, with the posterior margin incurved. Anteriorly they bear
an extension below the general surface, and separated by a furrow. This
forms a surface of articulation along which the segments are movable, and is
covered by the edge of the segment immediately in front, so that it is chiefly
visible in coiled or disarticulated specimens. Barrande distinguished two
types of pleura : (a) furrowed pleura (plewe a sillon), which have a diagonal
furrow on the upper surface, running posteriorly from the anterior edge near
the axis, and towards the free extremity ; and (b) ridged pleura (plewe a
bourrelet), having a longitudinal ridge or narrow fold. These characters vary
considerably, and are sometimes obscure. In a small number of genera
(Illaenus, Nileus) the pleura are perfectly smooth.

All pleura show a distal or lateral, and a proximal or inner portion. The
latter extends from the axis to the fulcrum or bend, i.e. to a place where the
pleura bend more or less abruptly downward, and also generally toward the
rear. The distal portion, beginning at the fulcrum, may continue of equal
thickness and be rounded or obtuse at the extremity, or it may decrease in
size and terminate in a spine.

The number of thoracic segments varies exceedingly among different
genera. The smallest number (2) occurs in Agnostus. The largest number
so far observed (29) is found in some species of Harpes. A variation is to be
noted even among the species of a single genus, hence this character is not of
general application for purposes of classification. For example, there are
species of Ampyx and Aeglina with five to six thoracic segments, Phillipsia with
nine to fifteen, Cheirurus with ten to twelve, Cyphaspis with ten to seventeen,

BUB-OLAM I TIMI.oniTA

with ten to fourteen, and /'»//-i///...r/W.> with -ixteen to t wentv.
In general, there seems to be a sort of mutual relationship between tin- numl er
of thoracic segments and the si/e of the pygidium. When tin- lattci i> lar^e.
the thoracic segments are usually few : hut if small, the number of segments
is large.

The Pygidiwn. — The abdomen of Trilobites is common Iv known as the
/tftffiilium (Fig. 1263), though sometimes styled the caudal shield or plate. It
consists of a single piece, with an arched upper surface, upon which may 1 e
distinguished regularly a median axis and two lateral parts, or pleural limbs,
marked more or less distinctly by transverse furrows. Sometimes it
considerable resemblance to the cephalic shield (./'///»>///>, .]//>/•/«//>»/.<). The

FIG. 1263. Fi«;.

Pyjiiclium of Ogygia Buchi, Brongt. Ordovician. Pygidium of /,';•<;//(.•"> miileU'ifer, Beyr.

Wales. Devonian; Bohemia.

pygidium evidently originated from the anchylosis of a number of similar
segments. The potential segmentation is often so strongly marked that it is
very difficult to recognise the dividing line between the thorax and pygidium,
except in disarticulated specimens. Sometimes the evidences of segmentation
disappear entirely or are but faintly indicated on the lower side. AVhen
segmentation along the axial and lateral lobes is weak, the pygidium varies
considerably in appearance from the thorax.

The axis may extend as far as the posterior end of the pygidium, or to
any part of the length, but is sometimes reduced to a short rudiment ( /;/'<>/if> n.--.
Fig. 1264), or it may be even entirely obscured (Nileus). The number of
axial segments normally corresponds to the number of pygidial, and varies
between two and twenty-eight. On the lateral lobes, all or at least a part of
the pleura may also be seen, being continued from the axis as ribs separated
by furrows. In these cases, the furrowed and the ribbed pleura can usually be
distinguished, but not infrequently they have entirely disappeared as surface
features. Many of the Cambrian Trilobites are conspicuous for their small
pygidium and elongated thorax.

The outline of the pygidium is most frequently semicircular, parabolic, or
elliptical; more rarely it is triangular or trapezoidal. The margin is entire,
less commonly dentate or spiny. The border, as in the case of the cephalon
and the pleura of the segments, has a reflexed margin, or doublure, which in
some genera attains considerable width.

The Ventral Side. — The ventral side of Trilobites is commonly inaccessible
for purposes of observation, since, as a rule, it is so firmly attached to the

614

ARTHROPODA

sri'.-KTNGDOM VII

rock that the organs, even though present, cannot be exposed by the ordinary
methods. Furthermore, the appendages and ventral structures are so thin
and delicate that the most favourable conditions are necessary for their pre-
servation. For this reason, great uncertainty has prevailed regarding the
presence and character of the legs and various appendages. After a careful
preparation of their inferior side, by far the larger number of Trilobites show
only the vacant hollow space beneath the dorsal shell, and the hypostoma
attached to the reflexed margin of the cephalic shield, as represented in Fig.
1266. This common condition of the fossils led Burmeister, in 1843, to the

assumption that all organs on the lower
side, as in Phyllopods, were originally soft
and fleshy. Previous to this, however,
Linnaeus, in 1759, described what
appeared to be antennae, and Eichwald,
in 1825, announced both antennae and
Altogether the early literature down to
1870 contains quite a number of claimants for
this discovery. Most of the evidence is manifestly
erroneous, and the two or three cases which bear
some semblance of validity are too obscure to be
of any scientific value.

Billings, in 1870, published the description
and figure of an unusually well-preserved Asaphus
(hotelus) gigas from the Trenton limestone of
Ottawa, Canada. The ventral side of the specimen
showed eight pairs of jointed feet on each side of
a median furrow (Fig. 1265, A}. Soon after,
/' Woodward described an antenna or pediform

cephalic appendage, lying beside the hypostoma
of another individual of the same species (Fig.
s, De Kay. 1265, B). Through the investigations of Walcott
ordovician; Ottawa"; "Canada, A, (1875-94) on Ceraurus and Caliimmene, by means of

Ventral side, showing remains of \ J . /. -,

jointed feet (after Biiiings). K, Hypo- transverse and longitudinal sections 01 enrolled
?ephlaiicTppendage'(after Woodward"! specimens, a number of problems have been settled

as to the characters of the ventral side. Accord-
ing to these investigations, Trilobites possessed a thin, external, ventral
membrane attached to the reflexed margin of the cephalon, the thoracic
segments, and pygidium. It
was supported by transverse c
processes which became cal-
careous with age, and to these
the feet were attached.

The intestinal Canal, dis- Median vertical section of Ceraums pleurexanthemvs, Green.
rnvprprl Vw "RpvnVVi and c> Cephalon with hypostoma below; m, Mouth; v, Ventral mem-

cover Dy ceyn ana ^v. .^ lntestinal ^nal . py> Pygidium (after Walcott).
volborth, is located beneath

the axial lobe, within the visceral cavity. It begins at the mouth, which
Walcott found at the posterior margin of the hypostoma, first bends forward
toward the dorsal region, and then extends backward from the glabella to
the posterior end of the pygidium, and parallel to the dorsal test, terminating
in the anal opening (Fig. 1266).

FIG. 1265.

8UB-CLA88 I

TRILOBITA

Most of the recent advances in tin- knowN-d^r of Tiilol.itr stnn-Mnr ha\.-
come from the study of nuinrmn> very prrfn-ily pn-i-r\rd .-.pi'i-im.
Trio /Hi ru.< ///••/•/', (Irern, hom tin- I'tira Shite (Ordovi<-ian). m-ar Koin>
York. Undoubted antrnnar in this form wnv discovered l»y \';iliant, ami tii>t
announced by Matthew in 189.'$. Subsequently a series of papn
published by Beecher on the detailed structure of this Trilobite, which is now

Fi.:. 12C.7.

Trio rtltrus Becki, Green. Utica Slate (Ordovician) ; Rome, New York. A, Dorsal, ami /;, V.-ntral aspect,
2/j (after Beecher).

the best known of any species, and necessarily forms the basis of much of the
following summary of ventral organs.

In the median line anteriorly, there is first the hypostoma or upper lip, at
the end of which, and opening obliquely backward, is the mouth (Walcott, in
Calymmene). In Trwrtlinix the lower lip, or metastoma, is a convex arcuate
plate, just posterior to the extremity of the hypostoma. At the angles on
either side are two small elevations, or lappets.

Paired Appendages. — All segments of the cranidium, thorax, and pygidium,
except the anal segment, carry paired appendages, which are all biramous save t In-
anterior pair. The anterior antennae, or antennules, are attached at the sides
of the hypostoma, and consist of a simple, many -jointed flagellum (Fig. 1267).

616

ARTHROPODA

SUB-KINGDOM VII

The normal Trilobite leg has two branches arising from a basal joint, or
coxopodite, which is prolonged into a gnathobase. The inner branch, or endo-
podite, has normally six joints. The outer branch, or exopodite, has a long
proximal joint, with a distal multiarticulate portion. Long setae extend
posteriorly, and on the distal portion they are so crowded as to make a con-
spicuous fringe, imparting a characteristic appearance to the leg.

Besides the antennules, the cephalon bears four pairs of pediform biramous
appendages, with large gnathobases functioning as manducatory organs. Of

Trial-Virus Becki, Green, a, Restored thoracic limbs in transverse
section of the animal ; 1>, Section across anterior portion of pygidium ;
c, Section across posterior portion of pygidium (after Beecher).

FIG. 1269.

Triarthrus Becki, Green.
Dorsal view of second thoracic
leg, with and without setae and
without gnathobase. en, Endo-
podite ; ex, Exopodite (after
Beecher).

these the first may be correlated with the posterior antennae of higher Crustacea.
In structure and function they are true mouth appendages, like the second

a b

FIG. 1270.

Ti-iiiiK-ltus concentricus, Eaton. Utica Slate (Ordovician) ; Rome, New York. A, Left half of pygidium
and three thoracic segments, with test removed, and showing fringes of the exopodites. B, Ventral aspect of
same, a, Endopodite ; b, Exopodite. 10/i (after Beecher).

pair of nauplius limbs. The second pair, corresponding to the mandibles of
higher forms, and the third and fourth, corresponding to maxillae, have the
same structure as the first, with large gnathobases and fringed exopodites.
The thoracic and abdominal limbs are of the same biramous type. The endo-
podites are jointed, crawling legs ; posteriorly, especially on the pygidium,

TBILOBITA <:i7

the joints become flattened HIM! leaf like, carrviim tufts of setae, and b
adapted for swimming.

The exopodite* arc fringed alon.u' their pn>i«-rinr rd.urs with narr«.\\.
oblique lamellar elements becoming filiform at the end.-. thu> cmm-i t in:: Jin-
limb into a swimming organ, and also serving respiratorv functions (Figs.
1267, 1270).

Habits. — In the absence of any closely allied recent forms, it is difficult to
reach definite conclusions respecting the manner of life of Trilobitus, except
such as are based upon their organisation and mode of occurrence. They
undoubted marine animals, since their remains are found only in salt water
deposits, associated with Brachiopods, Cephalopods, Crinoids, and other typical
oceanic forms. Some species are plentiful in calcareous or argillo-calcareous
deposits, with thick-shelled Brachiopods, Gastropods, and reef-building Corals,
which evidently did not live at any considerable depth. Other f«»nu> appear
to have been bottom crawlers, frequenting either muddy or sandy bottoms ;
and again, others like Triiim-lma, lived partly buried in the soft mud. On the
other hand, many species indicate, from the absence of visual organs, a com-
paratively deep-water habitat. The structure of the appendages of many was
probably such as to permit of both swimming and crawling, as in a number of
families of modern Crustacea, and they were therefore restricted neither to the
shore nor to the bottom. This doubtless explains the occurrence of the same
species in very different sediments.

Power of Enrolment. — The bodies of most Trilobites were capable of being
rolled up completely like many of the Isopods (Fig. 1271). In the enrolled
condition the margin of the pygidium is closely applied
to the doublure of the cephalon, thus entirely concealing
the ventral side of the body. The thoracic segments
overlap, and admit of more or less motion upon one
another. The pleura also imbricate, and their fulcra
are provided with facets upon which the fulcra of
adjacent segments impinge. The ends of the pleura
thus protect the ventral surface along the sides, when
the animal is enrolled. Some forms appear to have
possessed the power only to a limited degree. In
these, the creature is usually found extended, and the Enroiic.i
facets on the fulcra are either rudimentary or absent.

Ontogeny. — Minute spherical or ovoid fossils associated with Trilobites
have been described as possible Trilobite eggs, but nothing is known, of
course, of the embryonic stages of the animals themselves. The smallest and
most primitive organisms which have been detected, and traced by means of a
series of specimens through successive changes into adult Trilobites, are little
discoid or ovate bodies not more than 1 mm. in length. This first larval form
has been named the protaspis (Beecher), arid has been found to be the normal
larval type characteristic of all Trilobites. It is believed to approximate the
protonauplius form, or the theoretical, primitive, ancestral, larval form of the
Crustacea.

The simple characters possessed by the protaspis are the following, as
drawn from the study of this stage in all the principal groups of Trilobites : —
Dorsal shield minute, m>f ///<>r<' /////// 0'4 f<> 1 nun. in /»•«///// ; ciri-nlnr "/• "'•"/' i,i
form ; axis distinct, more or less sti-mi'ili/ rf///////r/W. I hit if'.-'/ Inj Imitfifm/imd g\

618

ARTHROPODA

SUB-KINGDOM VII

head portion predominating ; axis of cranidium with five unuuinl '/,>,, * ,• <il,l<nninal
portion usually less than one-third the length of the shield ; axis with from one to
several annulations ; pleural portion smooth or grooved ; eyes, when prwiif, < inferior
marginal, or submarginal ; free cheeks, when visible, narrow ami mar;// an/.

The changes taking place during the growth of an individual are chiefly
the following : — Elongation of the body through the gradual addition of the
free thoracic segments ; translation of the eyes, when present ; modifications
in the glabella ; growth of the free cheeks ; and final assumption of the mature
specific characters of pygidium arid ornamentation.

In a classification of the stages of growth, the protaspis has the rank of a
phylembryo, and corresponds in value to the protoconch of Cephalopods, the
prodissoconch of Pelecypods, and the protegulum of Brachiopods. In its
geological history and the metamorphoses it undergoes to produce the perfect
Trilobite, accurate information can be gained as to what the primitive char-,
acters are, and the relative values of other features acquired during the long
existence of the class.

Of the stages of growth after the protaspis, the nepionic may be considered
as including the animal when the cephalon and pygidium are distinct, and the

FIG. 1272.

Ptychoparin Kingi, Meek.
Cambrian. A, Protaspis en-
larged. B, Adult reduced.

FIG. 1273.

>'<") // ! r.-iutu, Barr. Cambrian.
A, Protaspis enlarged. B, Adult
reduced.

FIG. 1274.

Triarthrus Becki, Green.
Ordovician. A, Protaspis en-
larged. B, Adult reduced.

thorax incomplete. There would thus be as many nepionic stages as there
are thoracic segments. The neanic stages would be represented by the
animal with all parts complete, but with the average growth incomplete.

FIG. 1275.

Proetus parviusculus, Hall.
Ordovician. A, Protaspis
much enlarged. I',, Adult
slightly enlarged.

FIG. 1276.

Acidasnis tuberculo.ta,
Conrad. Devonian. ^Pro-
taspis enlarged. B, Adult
reduced.

FIG. 1277.

Dalmanites socialis, Barr.
Ordovician. A, Protaspis i-n-
larged. J>, Adult reduced.
(Figs. 1272-77 after Beecher.)

Final progressive growth and development of the individual would fall under
the ephebic stage. Lastly, general evidences of senility would be interpreted
as belonging to the gerontic stage.

Morphogeny. — During the protaspis stage, several moults take place before
the complete separation of the pygidium or the introduction of thoracic seg-
ments. These bring about various changes, namely, the stronger annulation
of the axis, the appearance of the free cheeks on the dorsal side, and develop-
ment of the pygidium by the introduction of new appendages and segments,

8UB-CLAS- I TIM Ll U'dTA 819

as indicated by the additional ,- ami lirnl*. In the earliest.

or Cambrian genera, the protaspia §tage i- i>v far the simplest e\pr« — i«»n of

this period to 1)0 found. In the higher ami lat. c«8 ef

acceleration or earlier inheritance has pu.-hed forward rrrtain character- until
they appear in the protaspis, thus making ii more ami moiv complex.

Taking the early protaspi.- Btagefl in >'"/>•/,„///, ,//•,/. /,/'os//v/f*/s, or /'///<7/<//«//-/'</.
it is found that they agree exactly with the foregoing dia^no.-i- in it.- mo.-t
elementary sense. Since they are the character! shared in common l>v all
larvae at this stage, they are taken aa j)rimitive, and accoi-ded that value in
dealing with adult forms possessing homologous features. Therefore, any
Trilobite with a large elongate cephalon, eyes rudimentary or absent
cheeks ventral or marginal, and glabella
long, cylindrical, and with five annulation>,
would naturally be placed near the beginning ^

of any genetic series, or as belonging to a ^2j| (^

very primitive stock.

Next must be considered the progressive *
addition of characters during the geological
history of the protaspis, and the ontogeny
of the individual during its growth from
the larval to its mature condition. It has
been shown by Beecher that there is an
exact correlation to be made between the
geological and zoological succession of first
larval stages and adult forms, and therefore
both may be reviewed together. Sao Mnuta, Ban. caiiii.nan ; skiv\.

rrn n ' Bohemia. A, Protasiiis. /.'-/•'. NVnionic stages

The first important structures not 0fderelopraelit(aft«rB«n»nde).

especially noticeable in all stages' of the

protaspis are the free cheeks, which usually manifest themselves in the meta-
or para-pro taspis stages, though sometimes even later. Since they bear tin-
visual areas of the eyes, when such are present, their appearance on the dorsal
shield is practically simultaneous with these organs, and before the eyes have
travelled over the margin, the free cheeks must be wholly ventral in position.
When first discernible, they are very narrow, and in Ptychoparia and Sao,
include the genal angles. In Dalmaniles and Cheimrus, however, the genal
angles are borne on the fixed cheeks.

Since the free cheeks are ventral in the earliest larval stages of all but the
highest Trilobites, and as this is an adult feature among a number of genera,
which on other grounds are very primitive, this is taken as generally indicative
of a very low rank. The geneir Y/"/yw.<, ?lifiti>t>fHst Trinucleus, and their allies
agree in this respect, and constitute the Hypoparia.

The remaining genera of Trilobites present two distinct types of head
structure, dependent upon the extent and character of the free cheeks. In
both, the free cheeks make up an essential part of the dorsal crust of the
cephalon, being continued on the ventral side only as a doublure or infolding
of the edge, similar to that of the free edge of the cranidium, the ends of the
thoracic pleura, and the margin of the pygidium. They may be separate* 1
only by the cranidium, as in Ptychoparia; by the cranidium and separate
epistomal or rostral plate, as in Illaenus and Homalonotus ; or they may In-
united and continuous in front, as in Aecjlina and Ihiluwnit''*. One type of

620

ARTHROPODA

SUB-KINGDOM VII

structure is distinguished by having the free cheeks include the genal angles,
thus cutting off more or less of the pleura of the occipital segment. The
genera belonging to this group constitute the second, order — the Opisthoparia.

The third and last type of structure includes forms in which the pleura of
the occipital segment extend the full width of the base of the cephalon, em-
bracing the genal angles. The free cheeks are therefore separated from the

FIG. 12V9.

Ontogeny of Sao hirsuta, Barr. (Opisthoparia) A, Protaspis. 7J, Cephalon of nepionic individual. C, Cephalon
.of later nepionic individual having eight free segments. D, Cephalon of adult (from Beecher, after Barrande). .

cranidium by sutures cutting the lateral margins of the cephalon in front of
the genal angles. Genera having this structure are here placed in the order
Proparia.

The characters still to be noticed have chiefly family and generic values,
and are of great assistance both in determining the place of a family in an
order and the rank and genetic position of a genus in a family.

There is very satisfactory evidence that the eyes have migrated from the
ventral side, first forward toward the margin, and then backward over the

FIG. 1280.

Ontogeny of Dalmanites sodalis, Barr. (Proparia) A, Protaspis. B, Cephalon of individual of three free
segments. C, Cephalon of one of seven free segments. 1), Cephalon of adult (from Beecher, after Barrande).

cephalon to their adult position. The most primitive larvae should therefore
present no evidence of eyes on the dorsal shield. Just such conditions are
fulfilled in the youngest larvae of Ptyclioparia, Solenopleura, and Liostracus.
The eye-line is present in the later larval and adolescent stages of these genera,
and persists to the adult condition. In Sao it has been pushed forward to the
earliest protaspis, and is also found in the two known larval stages of Triar-
thrus. Sao retains the eye-line throughout life, but in Triarthrus the adult has
no trace of it. A study of the genera of Trilobites shows that this is a very
archaic feature, chiefly characteristic of Cambrian genera, and only appearing
in the primitive genera of higher and later groups. It first develops in the
later larval stages of certain genera (Ptychoparia, etc.) ; next in the early larval
stages (Sao); then disappears from the adult stages (Triarthrus); and finally
is pushed out of the ontogeny (Dalmanites).

In Ptychoparia, Solenopleura, Liostracus, Sao, and Triarthrus, the eyes are
first visible on the margin of the dorsal shield after the protaspis stages have
been passed through, and later than the appearance of the eye-lines ; but in
Proetus, Acidaspis, Arges, and Dalmanites, through acceleration, they are present
in all the protaspis stages, and persist to the mature or ephebic condition,

SUB-CLAss I

moving in from the margin ID near the sides «.t tin- glaKella. Progression in
these characters may lie expressed, and in so far taken for general application
among adult forms to indicate rank, as follows : — (1) Absence of eyes ; (2) ey^i-
lines ; (3) eye-lines and marginal eyes; (4) marginal eyes; (5) sulnn
eyes; (6) eyes near the pleura of the neck segment.

The changes in the glabella are equally important and interesting.
Throughout the larval stages the axis of the cranidium shows distinctly l»y
the annulations that it is composed of five fused segments, indicating tin-
presence of as manv paired appendages on the ventral side. In its simplest
and most primitive state it expands in front, joining and forming the anterior
margin of the head (larval Ptyckoparia and N</</). During later growth it
becomes rounded in front, and terminates within the margin. In higher
genera, through acceleration, it is rounded and troll-defined in front, even in
the earliest larval stages, and often ends within the margin (larval Tim rtlirn*
and Acidaspit). From these few simple types of pentamerous glabellae, all
the diverse forms among species of various genera have been derived, through
changes affecting any or all of the lobes. The modifications usually consist in
the progressive obsolescence of the anterior annulations, finally producing a
smooth glabella, as in Illaenus and Niobe. The neck segment is the most per
sistent of all, and is rarely obscured. The third, or mandibular segment is
frequently marked by two entirely separate lateral lobes, as in Acidaspis, Oono-
lichas, Chasmops, etc. Likewise, the fourth annulation carrying the first pair
of maxillae is often similarly modified in the same genera, also in all the
Proetidae, and in Cheirurus, Crotalocephalus, Sphaerexochus, Ampyx, Harpes, etc.
Here, again, among adult forms, the stages of progressive differentiation may
be taken as indicating the relative rank of the genera.

The comparative areal growth of the free cheeks is expressed by the
gradual moving of the facial suture toward the axis. As the free cheeks
become larger the fixed cheeks become smaller. In the most primitive pro
taspis stages, and in Agnostus, Harpes, and Triuucleus, the dorsal surface of the
cephalon is wholly occupied by the axis and fixed cheeks, while in the higher
genera the area of the fixed cheeks becomes reduced until, as in &////////»/ and
Phillipsia, they form a mere border to the glabella. Therefore the ratio
between the fixed and free cheeks furnishes another means of assisting in the
determination of rank.

The pleura from the segments of the glabella are occasionally visible, as
in the young of JElliptocephala, but usually the pleura of the neck segments are
the first and only ones to be distinguished on the cephalon, the others being
so completely coalesced as to lose all traces of their individuality. The pleura
of the pygidium appear soon after the earliest pro taspis stage, and in some
genera (Sao, Dalmanites) are even more strongly marked than in the adult
state, and much resemble separate segments. The growth of the pygidium i.-
very considerable through the protaspis stage. At first it is less than one-
third the length of the dorsal shield, but by successive addition of segments it
soon becomes nearly one-half as long. In some genera it is completed before
the appearance of the free thoracic segments, all of which are added during the
nepionic stages. An interpretation of these facts, to apply in valuing adult
characters, would indicate that a very few segments, both in thorax and
pygidium, may be evidence of arrested development or suppression. On the
other hand, the apparently unlimited multiplication of thoracic and especially

622 ARTHROPODA SUB-KINGDOM vir

of abdominal segments in some genera is also to be considered as a primitive
character expressive of an annelidan style of growth. Genera, like As<i./>liu.<}
Phacops, etc., having a constant number of thoracic segments accompanied by
other characters of a high order, undoubtedly represent the normal Trilobite
type.

These analyses and correlations clearly show that there are characters
appearing in the adults of higher and later genera, which successively make
their appearance in the protaspis stage, sometimes to the exclusion or modifica-
tion of structures present in the more primitive larvae. Thus the larvae of
Dalmanites or Proetus, with their prominent eyes and glabella distinctly
terminated and rounded in front, have characters which do not appear in the
larval stages of ancient genera, but which may come in their adult stages.
Evidently such modifications have been acquired by the action of the law of
earlier inheritance or tachygenesis.

Position in the Zoological System. — Since Trilobites have been made the sub-
ject of special study, they have been commonly classed with the Crustacea, and
placed near the Phyllopods by most observers. Quite a number of naturalists,
however, still divorce the Trilobites and Limuloids from the Crustacea, and
ally them with the Arachnids. Leaving aside the question of the homologies
of Limulus, it is a fact that Trilobites show the clearest evidence of primitive
Crustacean affinities, in their protonauplius larval form, their hypostoma and
metastoma, the five pairs of cephalic appendages, the slender jointed antennules,
the biramous character of all the other limbs, and their original phyllopodiforni
structure. They differ from Limulus, not only in most of these respects, but
also in not having an operculum. From Limulus and all other Arthropods
they are distinguished by having compound eyes on free cheek-pieces, which
apparently represent the pleura of a head segment that is otherwise lost,
except possibly in some forms of stalked eyes and in the cephalic neuromeres
of later forms. The most recent discussions as to the affinities of Trilobites
are to be found in the papers by Bernard, Kingsley, Woodward, and Beecher,
where, from the facts presented, the relationships of these animals with the
Crustacea follow as a necessary corollary.

As to the rank of the Trilobites in a classificatory scheme, there is also
much diversity of opinion. They have been long regarded as an order of
Crustaceans, but any attempt to include them in this way under higher groups,
such as the Entomostraca, Malacostraca, or Merostomata, results in such broad
generalities and looseness of definition as to render these divisions of little
value. The present state of knowledge of Trilobite structure and develop-
ment is in favour of assigning them nothing short of the rank of a
sub-class.

In nearly every particular, the Trilobite is very primitive, and closely
agrees with a theoretical Crustacean ancestor. Its affinities are with the
known sub-classes of the group, especially their lower orders, but its position is
not intermediate. The more primitive characters may be summarised as
follows : — (1) They are all free marine animals ; (2) they have a definite con-
figuration ; (3) the larva is a protonauplius-like form ; (4) the body and
abdomen are richly segmented, and the number of segments is variable ; (5)
the head is typically pentamerous ; (6) the thorax and abdomen are always
distinct, the number of segments in each being variable; (7) all segments
except the anal bear paired appendages ; (8) all appendages except antennules

BUB-CLAM i TIIII.nUITA— IIYI'UI'AIMA

are biramOUS ; and (10) the eo\al elements of all limli.s form -n.-uli-
which become orgiius of mambu atioii on tin- head.

Clii.wfirttfinii. Ban-ami.- givefl a complete iv-nni'- nf tin- rla-.-ilir;itions
applied to Trilobites down to ls."»n. ami -h<>\\> in a very satisfartory manner
the weak points of each, furnishing strong reasons as to whv thev arc un-
natural and therefore untenable. The underlying principles of tln'-t- e.ulv
attempts at a classification are here briefly >ummarised. (1) The first classifi-
cation of Trilobites was advanced by Brongniart in 182l', in which all the
forms previously known as AVo/W/7/nrs- ^/v»»/i../-//.s were shown to belong to five
distinct genera. (2) Dalman, 182G, made two groups, based ii])on the presence
or absence of eyes. (3) Quenstedt, 1837, recognised the number of thoracic
segments and the structure of the eyes as of the greatest important
Milne-Edwards, 1840, considered the power of enrolment as of prime value.
(5) Goldfuss, 1843, established three groups depending on the preset
absence of eyes arid their structurae. (6) Burmeister, 1843, accepted the two
divisions of Milne-Edwards, and laid stress on the nature of the pleura and the
size of the pygidium. (7) Emmrich's first scheme, 1839, was founded on the
shape of the pleura, the presence or absence of eyes and their structure. (8)
The later classification of the same author, published in 1844, depended on
whether the abdomen was composed of fused or free segments, and the minor
divisions were based chiefly on the structure of the eyes and the facial suture.
(9) Corda, 1847, placed all Trilobites in two groups, one having an entire
pygidial margin, and the other with the pygidium lobed or denticulate. (10)
M'Coy, 1849, took the presence or absence of a facet on the pleura for a
divisional character. As this is an indication of the relative power of enrol-
ment, it does not differ materially from the schemes of Milne-Edwards and
Burmeister. Zittel, in a review brought down to 1885, includes in addition
the schemes of (11) Barrande, 1850, and (12) Salter, 18G4, and remarks that
the basis of Barrande's general grouping, namely, the structure of the pleura,
has neither a high physiological nor a morphological significance. Both
Barrande and Salter recognise nearly the same families, with slight differences,
and the latter adopts a division into two lines, based on the number of body
rings and size of the pygidium. These include and are themselves included
in four groups, founded on the presence and form of the facial suture and the
structure of the eyes. (13) Chapman, in 1889, proposed four sub-on 1
primary groups based purely upon arbitrary features of general structure and
configuration, especially the form of the glabella, whether wide, conical, or
enlarged. (14) Haeckel, in 1896, divided the Trilobites into two orders
based upon the presence or absence of a functional pygidium.

In the classification here adopted, the families as defined by Salter and
Barrande are in the main adhered to, and the number corresponds very closely
with that in Zittel's ILim/lnn-h </< r /'uliicnnfnlnifii', and also with that in the
Grundziige of the same author. The ordinal divisions, and the definition.- and
arrangements of families, are taken from the classification prepared by Beecher
in 1897, based upon the study of ontogeny and morphogenesis, as already
shown.

Order 1. HYPOPARIA. Beecher.

Free cheeks formimj a coiiH/tinm.-; iimniiinil ventral j>/«te of the ccjihulon, am/ in
some forms also </.</< /*<////</ ,tvcr flu- ilnr*il side at the yenal «//;//•.<. >'«/«?••• vntral

624

ARTHROPODA

SUB-KINGDOM VII

tintrginal, or submarginal. Compound paired eyes absent ; simple eyes may occur on each
free cheek, singly or in pairs.

Even in the higher genera of this order, the suture is frequently unnoticed, hut can
be seen in all well-preserved specimens. In. Trinucleus and Harpes it follows the edge
of the cephalon, and separates the dorsal from the ventral plate of the pitted limb.
Since eye-spots occur on the fixed cheeks in the young of Trinucleus and adult Harpes,
it is prohahle that this character is a primitive one in the order, and has been lost in
Agnostus, Microdiscus, Ampyx, and Dionide.

The ontogeny of higher genera shows that the true eyes and free cheeks are first
developed ventrally, appearing later at the marginal, and then on the dorsal side <>!'
the cephalon. Therefore the Agnostidae, Trinucleidae, and Harpedidae have a very
primitive head structure, characteristic of the early larval forms of higher families.
Other secondary features show that this order, though the most primitive in many

FIG. 1281.
Cephala of Hypoparin. A, Agnostus. B, Microdiscus. C, Harpes. D, Trinucleus. E, Ampyx (after Beecher).

respects, is more specialised than either of the others, except in their highest genera.
The characters referred to are the glabella and pygidium. Very few species show the
primitive segmentation of the glabella, it being usually smooth and inflated and
resembling in its specialisation such higher genera as Proetus, Asaphus, and Lichas.
The pygidium often fails to indicate its true number of segments. Many species of
Agnostus and Microdiscus show no segments either on the axis or limb of the pygidium.
Trinucleus and others may have a numerously annulated axis and fewer grooves on the
pleural portions. The number of appendages corresponds to the axial divisions. The
multiplication of segments in the pygidium, and their consequent crowding, make them
quite rudimentary.

Family 1. Agnostidae. Dalinan.

Small forms, having the cephalon and pygidium elongate, nearly equal, and simi/nr
in form and markings. Free cheeks ventral, continuous ; suture marginal
or ventral. Eyes wanting. Thorax composed of from two to four seg-
ments, with grooved pleura. Cambrian and Ordovician.

Some species have spines at the genal angles, corresponding to the
interocular spines of Holmia and young
Elliptocephala, and not to the spinifonn
projections of the free cheeks. From their
abbreviated thorax:, and progressive loss <•!'
annulatioiis on the glabella and pygidial
axis, they must also be considered as de-
graded. Microdiscus, the earliest genus,
shows in some species the normal penta-
merous glabella, and annulated pygidial
axis, while the later genus Agnostus has lost
the •annulatioiis of both axis and pygidium.
Agnostus, Brongn. (Figs. 1281, yl-1283). Cephalon and pygidium without annula-
tions on their axes ; thoracic segments, two. Extraordinarily abundant in the Middle

Flu. 1282.

Agnostus grami-
lattts, Barr. Cam-
brian; Skrey,
Bohemia. 6/j
(after Barrande).

Agnostu» ,./>;/«,,///'.,•, Linn.
Cambrian ; Aiidrarum, Sweden.
Complete individual, and frag-
ment of limestone with detached
cephala and pyjjidia.

OHPKK I

HYPOPARLA

and rjij.i-i- Canil.i-ian and <>rdovi'-Jan r«n-k> ••!' I'.'.ln-ini.i. S
Spain, ;nnl America.

MicriHlfxnix, Kinnions (Fig. li'M. /; . < Vphalon ami pygidium .it'ii-n -li«.\vin^ thi-ir
segmented nature by annulationa "n their axes; thorax \\ith tin.-.- «r i-.ur -<-_'iiient-«.

( 'amlirian.

Family -2. Harpedidae. Jiarrande.

Cephalon /"/•*/<•, m'fli // l>rn«,l ni,n;/iini/ taepanrion «/• ////(/<; <il«.ii<ll<i >/»-./•/ </„,/ /,/-,,-
/•'/vr r/cr/.-x ventral, continuoui ; x//////-/ //////•»//'/«'/, /«<//<, (/•///</ ///. outer "/.•/• "/
Paired simple i>i/r-*j>i,t* ,,r ,,c,-lli\ sin, it,- or </«///</., .// ///• <//x/,// ,„,/.< ,,;" //•<//-/„///•/.•/»/
eye-lines on tin ji<-«l c/ii'/.-x. ••.< •/, ,/r////i/ ,,ntim r<l fr»in tin- iilnl,,-Uit.

jive to twenty-nine se<j i a i /if*, //•///; /•!//(/ ,/,•,>,, n<l j,l>m;i. /'//<//»///'///
(m Harpes) wry small, composed of Imf iln;- <»• /--///• >-.,//„, ,,/x.
Oixlovician to Devonian.

Harpes, in many respect.-, is one ..f the mo.-t inter.-iin-
genera of Trilobites, being very unlike other forms. The l.mad
hippocrepian pitted limb of the cephalon has its counterpart in
Trinucleus and Dionide, although less well developed in these
genera. The head is also relatively longer and larger, both
features being decidedly larval. It is the only family known in
which functional visual spots or ocelli are situated on the fixed
cheeks. The young Trinucleus has similar ocelli. The great
number of free segments in Haiyes is another primitive
character, and the cephalon still remains larger than the thorax
and pygidium.

Harpes, Goldfuss (Figs. 1281, C, 1284). Principally Ordovician and Silurian,
although a few Devonian forms are known.

Harpes unrjula, Stern-
b cr}; sp. Ordovician ;
Bohemia (after Barrande).

Family 3. Trinucleidae. Barrande.

Cephalon larger than the thorax or pygidium ; genal angles produced into .-;
Free cheeks continuous, almost wholly ventral, carrying the genal spines ; .<//////•. ///<>/•<////«/
or submaryinal. Paired simple eyes or ocelli generally «l>.« nt In mfulf /.</•///>• : <-i>mii«»n<1
eyes wanting. Thoracic segments five or six, with <in»/r,<l j,l, ,i,-<i.
Pygidium tr/>iinjnl<u- ; margin entire; axis with a number of

annufationt :

grooved, Ordo-

\ ician and Silurian.

Trinucleus,

I, h \\ yd
1281,* /',
Cephalon with a
broad, regularly
l>itted liorder, pro-

dllce<l hehiinl into

Tri nucleus

Barr. Ordovician (Et. D) ;
Wesela, Boliemia. 1/1-

i >.\

( )rdovirjan ; Kurope and

ments; axis narrow; pygidium triangular, wide, .-hurt.
North America.

Dionide, Barr. Like Trimn'l'-ti*, l>ut with irregularly punctate 1 .order, and larger
pygidium. Ordovician; Europe.

Ampyx, Dalman (Figs. 1286, 1287). Thorax ami pygidium resemMing /
VOL. I L' B

626

AKTHROPODA

SUB-KINGDOM VII

cephalon subtriangular, without pitted limb; glabella large, prominent, narrow be-
hind and enlarged anteriorly, often produced into a frontal spine. Genal angles
spiniform ; thoracic segments five or six. Chiefly Ordovician, rare in Silurian ;
-Europe and North America.

Order 2. OPISTHOPARIA. Beecher.

Free cheeks generally' separate, always bearing the genal angles. Facial sutures
extending forward from the posterior part of the cephalon within the genal angles, and
cutting the anterior margin separately, or more rarely uniting in front of the glabella.
Compound paired holochroal eyes on free cheeks, and well developed in all but the most
primitive family.

The families which are here placed under this order lend themselves quite readily
to an arrangement based upon the characters successively appearing in the ontogeny of
any of the higher forms. Thus, Sao, Ptychoparia, and other genera of the Olenidae
have first a protaspis stage only comparable in the structure of the cephalon with the
genera of the preceding order. Therefore this stage does not enter into consideration

FIG. 1288.

Cephala of Opisthoparia. A, Atops. B, Conocoryphe. C, Pti/<-liop<n-ii.i.
G, Proetus. H, Bronteus. I, Lichas. J, Addaspis (after Beecher). "

D, Olenus. E, Asuplms. F, I

in an arrangement of the families of the Opisthoparia. In the later stages, however,
there is a direct agreement of structure with the lower genera of this order. The
nepioiiic Sao, with two thoracic segments (Fig. 1279, B), has a head structure agreeing
in essential features with that in Atops or Conocoryphe (Figs. 1288, A, B). A later
nepioiiic stage, with eight thoracic segments (Fig. 1279, C) agrees closely with the
adult Ptychoparia or Olenus (Figs. 1288, C, D). These facts clearly indicate that the
family Oonocoryphidae should be put at the base of this extensive order. Moreover,
as Ptychoparia and Olenus are more primitive and simpler genera than Sao, they, as
typifying the family Olenidae, govern its position, which accordingly would be next
after the Conocoryphidae.

Variations in the position of the eyes, the relative size of the free and fixed cheeks,
and the degree of specialisation of the glabella have a definite order in the ontogeny of
any Trilobite, and furnish characters of taxonomic value in arranging the families
placed under the Opisthoparia (see Fig. 1288).

Family 1. Conocoryphidae. Angeliii.

Free cheeks very narrow, forming the lateral margins of the cephalon, and bearing tin'
genal spines. Fixed cheeks large, usually traversed by an eye-line extending from near
the anterior end of the glabella. Facial sutures running from just within the genal
angles, curving forward, and cutting the anterior lateral margins of the cephalon. Eyes

nlMSTllnl'AIMA

niiliiii'iit'trii or iiLo-at. Thnr.i.f »/•//// //•,/»,
small and offi-n- *•»/ //«///.-•. Cambrian.

The genera .ompri.-ed under this family piv-.-nl a numl.
characters, such as are displayed <.nly in the larval -tagi-s of higher fonn
cheeks are narrow and marginal, and may
be compared with those in the m-pinni.
stands of Sao and /'///,Yi«y*'f /•/(>. K\e- ha\.-
not been detected, but the presence of an
eye-line sugge.-ts their possible e\i-tenee.
The variations in the glabella are very
marked, and are a> great as those whidi in
higher forms attain some importance a-
family charaderi-t ic&

So far as known, all the larval forms
in the other families of the Opitthopana
agree in having the narrow marginal free
cheeks, hearing the genal angles. The eye-
line is present in most of the adult Olenidae,
and in the early stages of all so far as
known, so that the general average of char-
acters in the Conocoryphidae represents the conocoryphe &«/.:«•/•;, sciii..tii.

main larval features throughout the other Without ti^e free cheeks. Cam-

D r i a n ^rj t. c-y ; VJT i n 6 1 z,

Fi... l-.-.M.
< • I'lKilunof Atop*

families. Bohemia.^i/i.

Conocoryphe, Corda (Conocephalites,

Barr.), (Figs. 1289, 1290). Cephalon semicircular; genal angles produced into spine- :
glabella distinctly lobed, wide behind and contracted in front, not extending to the
frontal border. Fixed cheeks very large, with conspicuous furrow parallel -to the
anterior margin ; free cheeks narrow, marginal ; thorax of fourteen segment- Cam-
brian ; Europe and North America.

Atops, Emmons (Fig. 1291). Differs from Conocoryphc in having a more cylin-
drical and longer glabella, small pygidium, and >eventei-n free -egments. Lower
Cambrian ; North America.

Ctenocephalus, Corda. Like Conocortjjiln', but with a lobe in front of the glabella,
which is also less strongly denned ; free cheeks larger ; pygidium much smaller: five
segments fifteen. Cambrian; Europe and North America.

Bathynotus, Hall. Differs from Atop* and Ci.n><>,-<,riiji}n' in it.- wider a\i- : fre.-
cheeks united in front and extending backward into long genal spines ; thoracic seg-
ments thirteen ; pleura hastate. Lower Cambrian : Noith America.

Family -2. Olenidae. Salter.

Cephalon larger than the p<j<i f>!i'mn , //>•//»///// //•///»•/• tl,«,i In,,,/ • ,,,,},,! ,//y,//. -
produced into spines', free clweks .-•- 1><: /•»'/»'. Facial stiti'ri extending forward f/'"in (If
posterior margin of cephalon along the eye-lobes, and either ruttimi >},< anterior margin
separately, or meeting on the median line. Eyes crescent i<\ reniform, or
situated at the ends of eye-lines in all but the highest genera. Trunk /'<//«/, rum posed of
from eight (?) to twenty -six free segments. Pijiinlnnn frequently ."mull : marg
spinose. Principally Cambrian, but extending also into the Onlovidan.

Paradoxides, Brongt, (Figs. 1292, 1293). Glabella enlarging in front, lobes
denned; thorax with from seventeen to twenty free segments, pleura with >pinif..rm
or hastate extremities; pygidium a small plate-like termination of the axis, seg-
mented. Individuals sometimes attaining a length of OG m. or more. Very abundant
in the Middle Cambrian of Europe, North America, and Au-ttalia.

628

ARTHROPODA

SUB-KINGDOM VII

Olenellus, Hall. Fourteen free segments ; pygidium a long telson-like s])inc.
Lower Cambrian ; North America and Europe.

Holmia, Matthew (Fig. 1294). Sixteen free
segments ; pygidium a small plate without apparent
segmented divisions. Lower Cambrian ; Norway.

Remopleurides, Portlock
(Fig. 1295). Glabella ex-
panded ; axis wide ; free seg-

FIG. 1293.

Paradoxides (cf.
young of P. inflatus,
Corda sp. = Hydro-
cephalus carens,
Barr.). Cambrian;
Skrey, Bohemia.

FIG. 1294.

Jliilmia Kjerulfi, Linnarson. Cambrian;
Ringsaker, Xorway. Part of the glabella
removed, exposing hypostoma beneath. 3/4
(after Holm).

FIG. 1292.

Paradoxides BoTiemicus, Barr. Cam
brian (Et. C) ; Ginetz, Bohemia. i/2.

FIG. 1295.

Remopleurides
(Cuphyrct) radians,
Barr. O r d o v i c i a n
(Et. D) ; Konigshof.
Bohemia, l/i (after
Barrande).

FIG. 129(3.

Eurycare brevicauda, Ang. Cambrian
Andrannn, Sweden (after Angelin).

ments eleven to thirteen ; pygidium small, axis often reduced to two annulations, the
pleural portion produced behind into a flat expansion. Ordo-
vician ; Europe and North America.

Eurycare, Angelin (Fig. 1296). Cephalic shield short,
posterior angles produced into long curved spines ; thoracic
segments seven to nine. Cambrian ; Europe.

Olenus, Dalmau (Fig. 1297). Glabella defined, not narrow-
ing anteriorly ; thoracic segments twelve to fifteen, pleura with
sharp-pointed extremities, bent backwards; axis narrow, pygidium
small. Cambrian and Ordovician ; Europe.

Ptychoparia, Corda (Fig. 1288, C). Resembles Olenys, but
with tapering glabella, wrinkled limb, and larger pygidium.
Cambrian ; Europe and North America.

Agraulus, Corda. Body elongate oval ; cephalic shield large,
paraboloid, limb broad ; eyes small ; thoracic segments sixteen ; pygidium small, with
rounded margin and three annulations in the axis. Cambrian ; Europe and North
America.

FIG. 1297.

oli iiii*ti-tni<-<!t>ts, Briinn.
Cambrian ; Andrarum,
Sweden (after Angelin).

OKDKK II

OPI8THOPABLA

l'i. LS98) <Vpi,.-,ii,- -hi, -id itenidl
smooth, obtusely angular iii fr«.nt ; free cheeks short an. I narrow; thora-

twelve to lom-trrii : pygidium short, nidiinentarv. Cambrian; Kur-.p,
America.

S"o, Barr. (Figs. li'Ts. I :.'!)'.»>. <;]al,,.lla .-lightly tap.-ring foril
two-thirds tin- I'-n^th of tin- cranidiiun, and having tin. ; di.~tin<t

I'uiTiiw.- ; thoi

t t-.-ii ; p ygid i ii in \ .-i v -mal 1.

( 'anilu-ian : Kino],.-.

Tri'i rlli i •;/..-. ( ij, ,-n Fi<_'-. 1 i'T 1,
i:i»>0». (Jlaln-lla larir an- 1 \\.-ll-

Fio. 1298.

Schloth. Canihrian ;
Ginetz, BohtMnia.

FIG. 1299.

S«»o lilt-tutu, Barr.
Cambrian; Skrey,
Bohemia.

Fio. 1300.

Triaftkntt l'»'-ki, Green. Witli
antennae and legs. Ordovician ;
Rome, New York. »/o (after
Beecher).

fta. i.wi.

Owen. Cambrian; Wis

A, Cranidium. B, Pygidium (a(t»r

Hall).

defined, furrows not continuous; thoracic segments fourteen to >i\t.»-u: jih-ura
grooved; pygidiiun with six sfgiuents in the axis, margin cntii-c. Onlovii ian ;
Ameri<'a and Bcandinavia.

Owen (Fig. 1301). Cephalou large, crescentic ; glabella nol
tending to frontal margin ; eyes well developed ; thoracic st^nu-nts niin-. Pygidium
very large, Itroad and t'an-likf, with the sides jn-odiict-d povti-riorly into sjiiii'
with four to six riu^s, extending h-.— than two-tliirds the length of the pygidium.
(Janibrian ; North Anu-rica and Europe.

Family 3. Asaphidae. Emmrich.

Gephalon a ml /-//'//W///,,, /i-,7/ //. r,/nr,>d; ylabeUn »ft»i «./,.<,-»i /•,•///////»//•••'.
usually separate. Facial suhin-a extending forward* from ffi> y-x/ -//'.,/• ,-/-/. >,f th-
cephalon within tli< ijt'iml mi<ilt .>•, mi, I i-nttimj fli, htt<r«l or anterior ma -.'••/».»////

uniting in front of the <//"/«//". /-;/^.>- n*,i,itli/ present) xin<>"i}<, "•'•// J, r, fulfil, >•«.
of very consi<!<r«li/< size, even "mi/,,!,',,,/ ///, ,,iti,-> surfact <>j >!
generally composed of right <>r //•// >•»•*//// »/^x, ///// rm-iiing frnm ./''•' /" '•/». /'."
large, often with wide ,lnuhlnn: C'amlu'ian to Silurian.

Asaphus, Brongt. (Cr///»/"/» ////'".*, Eichw.), (Fi-:.-. 1 -(;">, 1288, C, 1302). Cephalic and
caudal shields of nearly equal si/c, with 1-i-oad infolded margin ; i^lal'ella expanded,

630 ARTHROPODA SUB-KINGDOM vn

nearly smooth ; free cheeks large ; hypostoma deeply forked ; eyes large and prominent ;

thoracic segments Bight

FIG. 1303.

Megalasp-is extenuata, Ang. Ordo-
vician ; East Gottland, Sweden. 1/1
(after Angelin).

broad ; eyes large.

FIG. 1302.
:, Linn. Ordovician ; Pulkowa, near St. Petersburg, Russia (after Salter).

pygidium not strongly segmented, often nearly smooth.
Some species attain a length of 0'6 m. Very profuse in
the Ordovician of Europe and North America.

Sub -genus: Meyalaspis, Angelin (Fig. 1303). Like'
Asaphus, but with more defined and cylindrical glabella.
Ordovician ; Europe.

Oyyyia, Brongt. (Fig. 1304). Glabella not greatly ex-
panded, and with four or five lateral furrows ; hypostoma
pentagonal, with rounded posterior margin ; thoracic seg-
ments with grooved pleura.
Ordovician ; Europe.

Illaenus, Dalman (Figs.
1288, F, 1305). Cephalic and
caudal shields large and convex,
semicircular in outline ; glabella
smooth, indistinct ; free cheeks
small ; hypostoma convex, ovoid,
posteriorly notched ; thoracic
segments usually ten, with
smooth pleura ; pygidium
smooth, with short and incon-
spicuous axis. Abundant in
the Ordovician and Silurian of
Europe, Asia, and North
America.

Nileus, Dalman. Thoracic
segments eight ; axis very
Ordovician; Europe.

FIG. 1305.

A, Illaenus Dalmani, Volb. Ordovician ; Pulkowa, near
St. Petersburg, Russia. Jl, C, I. crassiemula, Dalman.
Ordovician ; Dalekarlien, Sweden (after Holm).

FIG. 1304.

Ogygia Guettardi, Bro'ng. Or-
dovician; Angers, France.
Mechanically deformed indi-
vidual (after Brongniart).

Aeylina, Barr. (Fig. 1306). Glabella strongly convex, prominent, smooth; fixed

<>KIU:K

OPISTHOPARIA

.1. Nat. M/-. /;, »f, K

//,»//•<//'// • ntire or

cheeks Mippressed : ,.\vs very large, occupying n.-aily tin- whole an-a ..f ti

cheeks; thoracic segments five

grooved; pygidium IIILT, with >lmrt a\i-.

Ordovician ; Europe.

Family 4. Proetidae. Harrande.

CepJidlon ,'li,, lit on, -tin, ;l of fh, irJiol, ,niiii,,il :
it mil,. < i/, a, rullii jir»tln,;il into gp

fn in i<l, n- it It tn-o In 1 1 ml li(i.«(l loin*
In/ obliqn, fnrron:< in front of ///, ,/,,/•

Free elm!.-* /"/•//-, separate, >'"////•..-
extending from il« i>o.<t,ri,,r uinniin /'//(/•»//•«/ to
the eyes, and then forward, cutting tl,, anterioi
Eyes wualiy proinini nt, oft, ,,
Thorax of from cii/ltt to twenty-two free (after 'BE
segment*, with grooved pleura. Pygidium n*nnllii
of munij segments; pleural and axial portions stron'ilij
dentate. Ordovician to Permian.

Proetus, Steininger (Figs. 1275, 1307). Head-shield semicircular, with thickened
marginal rim ; glabella well denned, extending nearly to the anterior margin, lateral
furrows obsolescent, basal lobes often present. Eyes large,
crescentic, near the glabella ; thoracic segments usually ten,
pleura grooved; pygidium semicircular, margin entire; axis
elevated, segmented ; limb ribbed. Ordovician to Carbon-
iferous ; common in the Devonian.

Phillipsia, Portlock (Fig. 1308). Like Proetua, but with
more prominent glabella, strong basal lol.e-, and larger, more
segmented pygidium; thoracic segments nine. Thi- -«-nus
replaces Proetus in the
later Palaeozoic hori-
zona Tlie last surviv-
ing species occurs in
the Permian of North
America. Maximum
Fl°- 13o:- development in Lower

Bohf.micus, Corda. ( 1.irhn-iiifpTiui<

»,imian(Et.E);Ko,1iepmS> l ,,„

Bohemia (after Barrande). ArethUfWa, Hal r.

(Fig. 1309). (llaLella ^

about half the total length of head->liield, jji!;:;^,"1"' : Kil(lale-
contracted towai-d the front, with oblique
latei-al t'uri'ows and ba.-al lol.es; fixed '-heeks large; eyefl >mall, situated at the ends of
distinct eye-lines from the glabella ; ihorax with twenty-two -hort -c---ineiit- : 'pygidium
small. This is the most primitive gemu ..f the family, and the only -ne'
archaic eye-lines. The eyes, too, are more distant and f«.rwanl than in other
and the number of thoracic Moment- i- larger. Ordovician :

Fi...

Han. Ordnviciau
(Kt. l»):

Family 5. Bronteidae. IJarrande.

Dorsal Meld broad I ;i '/tijifi,;,/. i ',„!,,, I, ,„ less tl,,i,i one-third '/••
ylabella raffily*vxpandin<i in front, n-!t J, joint indications "f lol !«*

than the fixed. Faswl sutitrea extending from the posterior margin ./'">' o,],,,,,i *!<• "/'.-•
abruptly inward around the palpebral lobes, and then <///••./••/''/«.•/ ""'/ cutting •'//•

632

AKTHROPODA

SUB-KINGDOM VII

lateral margins separately.

(Et.

FIG. 1310.

Konieprus, Bohemia (after Barrande).

Eyes crescentic. Thorax of ten segments, with ridged pb'.urn.
Pygidium longer than cephalon or thorax ; axis
very short, with radiating furrows extending
from it across the broad limb toward the margin;
doublure very wide; margin generally entire.
Ordovician to Devonian.

Tliis comprises the single genus Eronteus,
Goldfuss (Figs. 1264, 1288, H, 1310). Ordo-
vician to Devonian ; Europe and North
America. Most abundant in the Silurian and
Devonian of Bohemia.

Famil 6. Lichadidae. Barrande.

Dorsal shield generally large and flat, with granulated test. Cephalon small, not
more than one-fourth the entire length ; genal angles spiniform. Free cheeks separate';
sutures extending from the posterior margin obliquely inward to the eyes, and then almost
directly forward, cutting the margin separately. Glabella broad, ivith a large, often
tumid central lobe, and from one to three side lobes. Eyes not large. Thorax with nine
or ten segments, and grooved and falcate pleura. Pygidium large, flat, commonly with
toothed, or notched margin corresponding to the pleural grooves ; doublure very broad.
Ordovician to Devonian.

Most of the forms of this family are above the average size of Trilobites, and
several species are among the largest of the class.
They are all thin-shelled, and so loosely articu-
lated that entire specimens are extremely rare.

Lichas, Dalmaii s. str. (Figs. 1262, 1311).
Anterior lobe of the glabella dominating the
other lobes, and continuous with the axis ;
lateral lobes reniform and small. Ordovician
and Silurian ; Europe and North America.

Sub-genera : Arges, Goldf. (Fig. 1 3 12). Lateral
lobes of glabella strongly defined, nearly as large
as the central one, and divided transversely by a
furrow ; lobes and neck ring often spiniferous ;
pygidium with dentate margin and spiniform Sweden (after

1 •* fe \ Angelm).

pleural extensions. Silurian and Devonian.

Dicranogmus, Corda (Fig. 1313). Glabella divided by two longitudinal and one
transverse furrow into angular lobes ; pygidium with simulated axis ; limb with a

few short denticula-
tions. Silurian.

Conolichas, Dames
(Fig. 1314). Glabella
having one large pro-
truding central, and
two prominent lateral
lobes, with sometimes
two smaller basal
lobes. Ordovician to
Devonian.

Ceratolichas, Hall
and Clarke (Fig.

1315). Central lobe arched, tumid, with smaller side lobes ; central lobe and occipital
ring with long curved spines. Devonian ; North America,

Arges armatiiA, Gold-
fuss. Devonian ; Ger-
many (after Beyrich).

FIG. 1313.
Dicranogmus
jiti/nniiriis, Hall
and Clarke. Sil-
u r i a n ; New
York.

FIG. 1314.

i 'onolLhas Schmidti, Darnes.
Ordovician ; Germany (after
Dames).

Fio. 1315.

Ceratolichas gryps, Hall
and Clarke. Devonian ; New
York (after Hall and Clarke).

in

PROPARIA

,iti;il,'.<

lateral

apinote, ''•/</« »/<»//

nfni. lilitlhlln //'//// «//-

<7i<r/-x /«/•</-, x.yi/f /•.//..

Family 7. Acidaspidae.

lijitn-nl, iiiinili-"-

,,,,,lni,i ,11 nil /.,/,. ,,,«/ /,-•-, Of
- ,/, /,.///,./

forward^

cutting fli>- anterior //»"/•.//// «"•// .>•/«/• i>f tin «//<//.-//»/.

segments, u- it h /•/</</•</ y//. ///•»/ »•.-•/, ,,,/,r/ /////< ImUmr .<{.
Pygidium usually .>•///»>//, i/v'/A .</<///n//x ///(//•(////. Oi-il-.-
vician to Devonian.

In this family, as well as in the Li<-lnnliil>i> , \- to
be found tin- high«-st expression of differentiation and
specialisation among the Opt0<A0pana, The primitive
peutamerous lobation of the axis of the cianidium is
entirely obscured, and is only clearly seen in the protaspis
and early nepionic stages. These two families are very
closely related, the chief differences being noted in tin-
size and character of the pygidium, and the ribbed or
grooved pleura. The Lichades are generally much
larger and flatter, but the smaller and spinose forms of
Arges and Ceratolichas approach quite near some of the
Acidaspidae.

Acidaspis, Murch. (Figs. 1276, 1288, /, 1316).
Ordovician to Devonian ; Europe and North America.

Dicranurus, Conrad; Ancyropyye, Clarke; Devonian. (Et. E); St
Selenopeltis, Corda ; Ordovician.

FIG. 1316.

A<-i'l"»/i!.-< li>n',; „,.,.:_ Ban. Silurian

I : ; •

Order 3. PROPARIA. Beecher.

Free cheeks not bearing the genal angles. Facial ntfwrei extending from tin-
margins of the ceplialon in front of the genal «/<///•-.>•, iim-m-il mul /•//-, /w/,/, cutting th-
anterior margin separately or uniting in front of the glabella. Compound paired 0y«f
scarcely developed or sometimes absent in the most primitive family ; "'<H <I> r,l<,j>.<f ,/////
schizochroal in the highest family.

This is the only order of Trilobites which apparently lu-gins during the known
Palaeozoic, and unlike the other orders, had no pre-< 'ambrian <-xi~t«-m •«-. The earli«-.-t
forms of the Proparia were initiated at the close of the Cambrian and dawn of the
Ordovician. The greatest generic differentiation of the group was early attained :
during the Silurian and Devonian a rapid decline niMied, and only .»n«- <T two genera
survived into the beginning of the ( Sarboniferoua

Among the Opifthoparia, it was shown that the Conocoryphidat formed tin-
natural base or most primitive family in the order, and was di>tingui>hed by tin-
narrow marginal free cheeks and absence of well -developed eyes, It i.- <-t
interest and importance to be able to recognise in tin- l'r"/i>irin a Hinilar primitive
family having characters in common \\iih the other, but still clearly belonging
to the higher order. Finn, j,,, ,•/'«, Arn'n, and Dindymem <>t' tin- /•;//.•;•/»»»/•/»/.»,
constitute a group of apparently blind Trilo1>ites with narrow marginal tVee cheeks,
and present in general the appearance of At»/>.<. i'nn<«-<>njtihe, Ctenocq)li»l"<. etc., of the
Conocoryphidae.

634

ARTHROPODA

SUB-KINGDOM VII

Family 1. Encrinuridae. Linnarsson.

Cephalon narrow, transverse. Fixed cheeks very large. Free cheeks long, narrow,
separate, sometimes with a free rostral plate between the anterior extremities. Sutures
extending from in front of the genal angles obliquely forward, and cutting the anterior
margin in front of the glabella. Eyes very small or absent. Thorax of from nine to

FIG. 1317.

Cephala -of Proparia. A, Placoparia. B, Encrinurus. C, Calymmene. D, Dipleura. E, Cheirurv.s (Eccop-
tocheile). F, G, Dalmanites. H, Chasmops. I, Acaste. J, Phacops (after Beecher).

twelve segments, with ridged pleura. Pygidium generally composed of many segments ;

limb with strong ribs usually less in number than the annulations of the axis. Ordo-

vician and Silurian.

Encrinurus, Emmrich (Cromus, Barr.), (Figs. 1262, 1317, 5-1319). Cephalon

tuberculated ; glabella pyrilbrm, ])romineiit ;
free cheeks narrow, separated in front by a
small rostral plate ; eyes small, elevated on
conical prominences ; thoracic segments eleven ;
pygidium triangular, numerously segmented,
limb with fewer ribs. Ordoviciaii and Silurian ;
Europe and America.

Placoparia, Corda (Fig. 1317, A). Glabella
more strongly lobed than in Encrinurus ; eyes

obsolete ; free cheeks long, narrow ; thorax of twelve segments ; pygidium small, with

few segments. Ordovician ; Europe.

FIG. 1318.

E-ncrinurus punc
tatus, Eminr. Sil
urian ; Gottland.

FIG. 1319.

Encrinurus Bohemians,
Barr. Silurian (Et. E);
Lochkow, Boheinia.

Family 2. Calymmenidae. Brongniart.

Cephalon somewhat wider than long. Fixed cheeks large; genal angles rounded or
produced into spines. Glabella narrowing anteriorly. Free
cheeks long, separate, usually with a free plate between the
anterior extremities. Sutures extending from just in front of
the genal angles, converging anteriorly, and cutting &he margins
separately. Eyes small, facets numerous, visual surface seldom
preserved. Thorax of thirteen segments, with grooved pleura.
Pygidium of from six to fourteen segments; axis tapering.
Ordovician to Devonian.

Calymmene, Brongt. (Figs. 1317, C, 1320). Body oval in
outline, possessing ,the power of enrolment to perfection ;

TV -n -i -1 T-ij-i.-i • c

glabella conical, strongly convex, divided by three pairs of
deep lateral grooves ; eyes small ; hypostoma quadrate,
notched. Thorax of thirteen segments, axial furrows deep ; pygidium of from six to

FIG. 1320.

Cnlyminene srnaria, Conrad.
Ordovician ; Cincinnati, Ohio.

OKDKU III

PROPAKIA

030

132-J.

Ckitrut li'-yr.

(Et. E); Kozolu].,
(after Barramlf).

Silurian

eleven segments, u,,t distinctly marked ,,||- from the thorax.

Kurope and North

America : also I )e

vonian of North

America.

H o m a I on <>f n .-•,
Koenig (Fig. I:',- 1 .
Body usually large,
elongate, narrowing
In-hind, indistinctly
trilobed ; gbihclla
smooth, flattened and
almost quadrate :
liygidium elongate
triangular, posterior
margin rounded or
pointed, axis with
ten to fourteen annu-
lations, sometimes
smooth and without
apparent segments.
Ordovician to De-
vonian ; Europe,
America, and South
Africa.

Family 3. Cheiru-
ridae. Salter.

Glabella well de-
fined. Free cheeks
small, sometimes much
reduced. Sutures

extending from in front of ///- ,/, „,// „,/,//,,.• inward to > >h< n

obliquely forward, cutting the <ini<-riar //«'/•<///> /// front «n,l on each
side of the glabella. Eyes n*n«Uii s///////. Tliorx., <;/"/'/•«/.•<
eighteen seijnnn/.-; <i< nerally eleven ; pi n r« <;/>-// .</•//»/«// into
spines. Pygidiwn *//;<>//, /'•//// from ////•-- to five teg$
elements commonly proJnrnl info .-•/<//">•. Principally Ordovician
and Silurian, l>ut extending into the Devonian.

Cheirnni.^ T-eyr. (Figs. 1 317, E, 1322). Glabella strongly convex
and deeply grooved by three ]»aiis of lateral furrow-; thoracic
segments eleven, WO « raivly nine to thirteen : pygidium with well-
marked axis of lour simulations, the pleura ju-oloiigcd into points
or spines. Species grouped into a number of -ub-gt-m-ra. Ordo-
vician and Silurian : Kuiope and North America.

Amphion, Pander (Fig. 1323). CVphalon broad and short,
with a distinct rim around the margin ; ghd>ella not .-trough
elevated, marked by two pairs of >id«- furrow- and >h«»rt frontal
furrow.-. rrhoraeic segments fifteen to eighteen with inflated
Silurian; pleura; pygidium smaller than cephaloii, pleural rib- extended
into spines. Commonly found in the enrolled condition. Ordo-
vician ; Europe and North America.
Sphaerexochus, Beyr. (Fig. 1324). (Ilabella ovoid or globular, with three paire of

Fin. 1321.

dn-.'ii. Silurian

lit J/jii i,n-
Lockport,

Kich\v.
Russia.

Ki...
of .(„
Onluvician : I'ulkuwa,

FIG. 1324.

'uis minis,

Beyr.

Listice, Bohemia.

(after Barrancle).

636

ARTHROPODA

SUB-KINGDOM VII

lateral furrows, the posterior one cutting off sub-circular basal lobes. Eyes small ;
thoracic segments ten, with smooth convex pleura :
pygidium smaller than head-shield, composed of three
segments, free at their ends. Ordovician and Silurian ;
Europe and North America.

Deiphon, Barr. (Fig. 1325). Glabella globular, without
lateral furrows ; free cheeks minute ; fixed cheeks pro-
duced at either side into a long curved spine. Eyes
small, situated at the base of the spiniform fixed cheeks ;
thoracic segments nine, with free spiniform pleura ;
pygidium short, giving off two pairs of curved spinous
processes. Silurian ; Europe.

Deiplion Forbesi, Barr. Silurian
(Et. E); St. Iwan, Bohemia (after
Barrande).

FIG. 1327.

Phacops latifrons, Bronn.
vonian; Gerolstein, Eifel
District.

Fio. 1326.

Phacops Stern if i'ii i,

Family 4. Phacopidae. Salter.

FIG. 1325.

Glabella tumid, ividest in front. Free cheeks con-
tinuous, united anteriorly. Suture
extending from in front of the genal

angles inward to the eyes, and thence forward around the glabella.
Eyes generally large, always with distinct facets, schizochroal. Thorax
of eleven segments, with grooved pleura. Pygidium usually large and
of many segments ; limb ribbed ; margin
entire or dentate. Ordovician to
Devonian.

Phacops, Emmrich (Figs. 1317, J,
1326, 1327). Glabella very wide and
rounded in front, the two anterior pairs
of lateral furrows inconspicuous or
obsolete ; genal angles short, generally
rounded ; eyes large, prominent ; pleura
De- rounded ; pygidium semicircular, margin

entire. Silurian to Upper Devonian ; Barr. "Devonian (Et.
_ , . G) ; Hostin, Bohemia

Europe and America. (after Barrande).

Trimerocephalus, M'Coy. Glabella tumid in front, lateral

furrows faint or wanting except the basal one ; fixed cheeks large ; free cheeks forming

a narrow anterior rim \
eyes small, with a few
large facets ; pygidium
small. Silurian and
Devonian ; Europe.

Pterygometopus,
Schmidt (Fig. 1328).
Cephalon obtusely an-
gular in front; glabella
enlarging anteriorly,
lateral furrows well
defined ; pygidium as
in Phacops. Ordovic-
Flo. 1329. ' ian ; Europe and North

FIG. 1330. America.

Dalmanites socialis, Barr. Ordovician (Et. D)
Wesela, near Prague, Bohemia. Cephalon, 1/1-

FIG. 1328.

Pterygometopus sderops,
I) aim. Ordovician ;
Jswos, Esthonia (after
Schmidt).

Acaste Downinrjiae,
Murch. Silurian ; Ludlow,
England (after Salter).

Glabella slightly enlarging, with distinct lateral

A caste, Goldf.
(Figs. 1317, /, 1329).
furrows ; pygidium often

oKIMJK III

PROPARIA

pointed, ;ui(l usually with more -egments than in i'lun-nj,.*. ( >rdo\ jrian and Silurian;
Europe.

Daknanites, Kmmri.h Figa L261, m7. /•'. '-. I :',:'.<». I :n i . <;],iL.n;l with

well<- marked lateral furrow-: genal angle- produced into
spines; eyes large, prominent, ami with many di-tinct facet-;

pygidium triangular, frequently pointed or niacromtad, with
more than eleven segment.-, -.met inies twenty <•!• more. < )i-do-
vician to Devonian ; Kuiope, America, and Ka.-t India.

Chasmops, M'Coy (Fig. i:*17,//. Ditfer- from I inl,,,,/ ,,,'t,. ^
in having the second pair of glabellar loin- nearly -epa rated
from the axis, in the obeoleeoenoe <>f the third pair of lol»-,
and in its rounded pygidium. Ordovieian ; Kurope.

Vertical Range and Distribution of Trilobites.

Trilobites are the only large division of the Arthr»]>»<l"
which has become extinct. K\vn in the earlie-t ('aml.rian
they bear evidence of great antiquity, — in their diver.-itied
form, larval modifications, polymerous head, and caudal shield.-.
These features show that Trilobite phylogeny must extend far
liack into pre-Cambrian times.

The maximum development of Trilobites occurred in the
Cambrian and Ordovician, after which they steadily waned

both in numbers and variety. The genera of the Conocory- /;,,/,„,,„ /,,.N //,„ „ /„,-„,.
vhidae are wholly restricted to the Cambrian, and here also Green. Silurian : Lockport]

e i i 11 ^.i r\i • j j t i-j i L • New York (after Hall).

are found nearly all the Olenidae and Aynostidae, only scattering

representatives of which survive into the Ordovician. The Asaphidae are the >ole
remaining family found in the Cambrian, and they are more characteristic of the
Ordovician and Silurian.

All families of Trilobites are present in the Ordovician, and continue into the
Silurian, with the exception of the Conocoryphidae, Aiiin>.<f/il>i>, and "/- /r />/»/., which
are properly Cambrian types. The Devonian witnesses a decline in the number of
families present, and with the close of this era, the class practically became extinct,
since only five genera of one family, the Proetidm; are met with in the < 'arboniferoiis.
and the single genus Phillipsia alone persists a* late as the Permian.

As regards their geographical distribution, some genera are of cosmopolitan occur-
rence : such as Agnostus, Conocoryplu>, I'fi/r}i<i/i'i /•/•/, 7'" /•<></',., /'/«.-•, 7V//M//7. //>-,
Illaenus, Proetus, Phillipsia, Addas-pis, Lichas, Calymmene, Homalonotus,
Phacops, Dalmanites, and others. The majority of forms, however, are extremely
limited in distribution, so that a laige number of genera found in Sweden, Bohemia,
England, and North America are unknown outside of certain very rot ii. ted areas;
and the total number of species common to both sides of the Atlantic is very .-mall.

A remarkable contrast is observable between the older Palaeo/oic Trilobites of tin-
northern parts of Europe, and those of the middle and southern portion-. While the
majority of northern genera and species are common to Great Britain, Scandinavia,
and Russia, the forms of the central Kuropean provinces (Bohemia, Thuringia, Fi<-htel-
berg, the Hartz, Belgium, Brittany, Northern Spain, Portugal, the Pyreiiee.-, the Alp-.
and Sardinia) are so dir-similar as to stand in closer relationships with the North
American than with the first-named Trilobite fauna. Of the :}.">'» >perie> found in
Norway and Sweden, and of the 275 in Bohemia, only >ix are common to both
provinces, and it is doubtful if the.-e are really identical.

The first of the accompanying tables shows tin- range and relative de\e]opm«-nt of
the orders and the class; the second represents the vertical range of tin-
families of Trilobites.

638

ARTHEOPODA

SUB-KINGDOM VII

TABLE SHOWING VERTICAL RANGE OF TRILOBITES.

Families.

Order 1, Hypoparia

Family 1. Agnostidae

2. Harpedidae .

3. Trinucleidae .

Order 2. Opisthoparia

Family 1. Conocoryphidae

2. Olenidae

3. Asaphidae

4. Proetidae

5. Bronteidae .

6. Lichadidae .

7. Acidaspidae .

Order 3. Proparia

Family 1. Encrinuridae .

2. Calymmenidae

3. Cheiruridae .

4. Phacopidae .

Total Number of Families

18

n

[The foregoing chapter on the Trilobita has been abbreviated from an essay prepared
expressly for this work by our foremost authority on the group, Professor Charles E. Beecher
of Yale University, New Haven. About a score of new figures have also been introduced in
the text, borrowed mainly from Dr. Beecher's original contributions. These last should be
consulted by every student in connection with the present chapter. — TRANS.]

BUB-CLAM B EUCRUSTACEA— PHYLLOPODA

Sub-Class B. EUCRUSTACEA. Kingsley. Crustacea prop

Crustacea not /w /•///// the /W// diridcil /'///« n»<li<nt *<//// ////»•/••// /i//*o- .-
jil/fnrm, plumose, <>r laun-llnti' ijilh in < itlnr ///»//•//••/'• <//• /?/«/•<//.

pairs of antem«i<, m«l //•//// ///<• ////*./•///<//• n/n/ ///<///<//7//rs /"/•//• /,/,///.,/ •///. ,\'"//y//i/.<
sta</6 either free-swimming or passed in //.-•

111 the Cnixfii'-Ki proper the appendages of tlir cep halot !.•

The first and second pairs arc prri>r;il and air known a- tli- . the

third pair, placed at either side of the moutli, arc tin- tiniinlii,!<* .• tin- fourth
and fifth pairs arc secondary jaws, called iniu-illm: The appciida^o liehind
these vary in character, MHIH- ln-in^ walking feet, while from one to three
pairs may be subsidiary to the maxillae in eating, in which case they are
called maxUlipeds.

The Eiuyntsfacea are commonly divided into E ntomostraca and M<>
but the first of these groups is not a homogeneous assemblage ; it is rather a
division in which have been placed all forms not members of the .1A//I/-W/-,/,-,/.
the almost universal presence of a nauplius stage being its chief ditl'erentia!
character. The Eucrustacea are here divided into the super-orders /'//////»/«*/</,
Ostracoda, Copepoda, Cirripedia, and Malacostraca.

Super-Order 1. PHYLLOPODA. Latreille.1

Eucrustacea of elongated form, often with distinctly segmented bodies, M>
with flat shield-shaped or laterally compressed carapace.

Under the Phyllopods are embraced very differently formed Crustaceans
of large and small size, living mostly in fresh water or salt marshes, and
possessing in common little else than the leaf-like form of leg and a uniform
developmental history. The segmentation of the body in higher forms
(Branchiopodd) is very distinct, but in the water-fleas (Cfadocerri) it is usuallv
quite incomplete. The number of body segments varies considerably
among different genera. In the strongly segmented forms the body i>
elongated and protected in front by a flat or shield-shaped dorsal cai apace
(Apus), or it is naked (Bmnchipus). In the Cladocera and /•,'>•////•/•//</'/<•, which
are enclosed in a bivalve shell, the body is laterally compressed, shortened.
and indistinctly segmented. The line of division between thorax and abdomen

1 Literature : A. Recent Forms.

Gnibe, E., Bemerkungen liber die Phyllopoden, etc. (Wiegmaun's Ardiiv fiir Natunrc^t li., XIX..
XXXI.), 1853-65. — Clans, C., Papers on Brauchipus, Apus, and Liinulus in AMiundl. (n^i-11-tli.
Wissensch. Gottingen, XVIIL, 1873 ; and Arbeit. Zool. In.st. \Vi,-n.. VI., 1886.- i: / /. .1 .

Zur Naturgeschichte der Daphniden (Zeitschr. Wisseusch. Zool., XXVII., XXXIII.), 1876-80.—
Lankester, E. R., Several papers on Liinulus, Apus, etc., iu Quart. Jouru. MUTDSC. Sor., XXI., 1881.

— Packard, A. S.t Monograph of the Phyllopod Crustacea of North America (12th Ann. Rrpt. t'.S.
Geogr. and Geol. Surv. Terr.), 1883.— Jfansen, 11. ./., Phyllopoda and C'irriiHjdia. Plankton Ex-
pedition, 1895.

B. Fossil Forms.

Jones, T. R., On Fossil Estheriae and their Distribution (Quar. .lonrn. Geol. Soc., XIX.), 1863.

— Monograph of the Fossil Estheriae (Palaeontogr. Soc.), 186*2. — 5th and 7th Repts. (.'.uniii.
British Assoc. Adv. Sci. on Fossil Pliyllopoda, 1887-89.— Geol. Mag. Sept. 1890, %b. 1891, Dec.
1893, July 1894.— Trans. Geol. Soc. Glasgow, IX., 1890.— Clarke, J. M.. N«-w Uvvonian Phyllnp...!-
(Amer. Journ. Sci., XXIII.), 1882.— 11« //../., ;md r,, ,,-/-.. ./. M.. Palaeontology of New York, VII..
p. 206, 1888.— Bernard, H. M., Fossil Apodida.- (Nat ScL, XI.), 1897.— Sch ,'••]„;•(. O, <»n the
fossil Phyllopod genera Dipeltis and Protocaris (Proc. U. S. Nat. M<>. MX. . 1897.

640

ARTHROPODA

SUB-KINGDOM VII

is seldom well defined; but, on the other hand, the head is sharply demarcated
from the rest of the body, and is usually provided with two pairs of antennae
and two large eyes, in addition to which there is often a small unpaired eye.
About the mouth are the large upper lip (hypostoma), two broad cornute
mandibles without palps, one or two pairs of maxillae, and often a lower lip
in the form of two elevations below the mandible.

To the thorax are attached foliaceous, overlapping, biramous legs ; these
usually occur in considerable numbers, and while rarely more than eight pairs,
they may vary from four to forty, and become smaller posteriorly. They
serve for swimming and grasping, and as a rule are supplied at the base with
respiratory tubes. The abdomen is partly without legs and frequently ends
in a segment bent down or recurved, and furnished with two claw-shaped or
expanded caudal appendages. All Phyllopods have the sexes distinct. The
males are usually much less numerous than the females, and the latter produce
chiefly by parthenogenesis.

Order 1. BRANCHIOPODA. Latreille.

Ten to forty or more pairs of leaf-like feet ; carapace, when present, shield-shaped or
bivalved ; in the latter case enclosing the whole body and capable of being closed by a
transverse adductor muscle.

Recent Branchiopods are almost exclusively inhabitants of fresh or brackish water,
the exceptions being found in strong brine, as in Great Salt Lake, etc. The males are
usually less numerous than the females, and in the case of some species several years
may pass without their appearance, the females reproducing parthenogenetically.

Family 1. Limnadiidae. Baird.

Carapace bivalved, containing the whole body, and closed by a transverse adductor
muscle. Antennae well developed ; eyes sessile ; thoracic legs in ten to twenty-eight pairs,
'he first one or two pairs in the male forming clasping organs. Abdomen small,
without appendages, and terminated by a pair of caudal processes.

Estheria, Riippel (Figs. 1332, 1333). Shell composed of two thin rounded valves,

FIG. 1332.

l:*th:-ria minuta, Alberti. Lettenkohle Dolo-
mite ; Sinsheim, Baden. A, 1/1- B, 6/j. C,
Portion of the exterior, so/j.

1333.

Estheria, sp. indet. Lower
barren Coal Measures; Carrollton,
Ohio. Umbonal portion showing
muscular or nuclear node, is/i.

united by a straight toothless margin. External surface concentrically ridged or
striated, and between the ridges are more or less regularly interlacing or branching

SUPER-ORDER I

I'HVLLOPODA

striae. The latter character serves to di.-tingui-li thi- p-nu- I'mm /'••

(p. 371). The beaks are not sharply defined, and tin- primitive portioot tOOMtiJllflB

bear a strong ocular or muscular iiMe.

This genus li;is iiuim-mus t,'.->il representatives, being firxt met with in :
i,m, and occurring
mostly in brackish
and shore deposits.
It abounds in the
productive Coal
Measures, in the
Permian,Trias (Let-
tenkohlen rn e rgel),
and \Vealden, and
has been found in A ,..„..„ T.^.~- T^ r,^ «„... „. D^»

Fio. 1334.

A, L>«'«> /..»/,/;. Jones. Coal Measures ; Pott-

the Pleistocene ville, Pennsylvania. B, L. Baentschiana, Geinitz. Srhteodimu capta, Clarke.

Coal Measures; Neunkirchen, near, Saarbritcken Hamilton; Cent«rfiel<i

(after Goldenberg). York. a/,.

Clays of Canada.

Leaia, Jones

(Fig. 1334). Carapace marked by one or two diagonal ridges which run from, the
anterior end of the dorsal margin toward the, lower margin. Carboniferous ; Europe
and North America,

Estheriella, Weiss. Carapace as in Estheria, but with radial riblets crossing the
concentric striae. Permian ; Eussia. Buntersandstein ; Saxony.

Schizodiscus, Clarke (Fig. 1335). Carapace peltate, with a straight hinge which i-
in the major axis of the shield. Each valve nearly a semicircle ;
surface marked with concentric ridges. Middle Devonian ;
New York.

Family 2. Apodidae. Burmeister.

Eyes sessile and head with a large shield -like carapace
extending over the thoracic segments; antennulae large and
triflagellate ; antennae greatly reduced except in the /»//•/•»/.
Thorax with thirty to forty pairs of foliaceous feet ; segmented
abdomen without appendages save a pair of caudal fibum nf.<.

Protocaris, Walcott (Fig. 1336). The oldest representative
of the ^ms-type, and exhibits a remarkable similarity to Apus
in its univalve carapace, multi-segmented abdomen, and single
pair of caudal spines. Lower Cambrian ; Vermont.

Apus, Schaff. (Lepidurus, Leach). Characters of the family. Trias to Recent.

Fio. 1336.

Protocaris Marshi, Wal-
cott. Cambrian ; Georgia,
Vermont. 2/3.

Family 3. Branchiopodidae. Baird.

Head distinct, eyes stalked ; carapace wanting. Thorax with eleven to nineteen pairt
of foliaceous feet ; abdomen terminating in two caudal processes.

Branchipodites, Woodward. Similar to the recent Branchipus. Oligocene of Bern-
bridge, Isle of Wight. (B. vectensis, Woodw.)

Anomalocaris, Whiteaves. This name has been applied to bodies from the
Cambrian of British Columbia which resemble the segmented abdomen of a Bram-hiu-
pod, each segment bearing a pair of lamellate appendages. Although tin- ol'jirt.-
abound where found, nothing is known of the carapace, nor is there any evidence of
the surface markings which characterise most Crustacean shields. Its affinities are
doubtful.

VOL.

2 T

642 ARTHROPODA SUB-KINGDOM vn

Order 2. CLADOCBRA. Milne-Edwards.

Phyllopods with bivalve shell which partially or entirely encloses the body ; antennae
large, forming swimming organs ; four pairs of leaf-like thoracic feet.

These have not yet been recognised with certainty in the fossil state. Possibly,
however, Lynceites ornatus, Goldenberg, from the Carboniferous, belongs here.

Super-Order 2. COPEPODA. Latreille.

Body elongate, usually distinctly segmented, the anterior somites being fused, the
posterior thoracic ones free. Both pairs of antennae well developed ; four or five pairs
of Uramms thoracic feet. Abdomen short or long, without appendages except for a
long caudal pair.

The Copepoda are without representatives in the fossil state.

Super-Order 3. OSTRACODA. Latreille.1

Small, indistinctly segmented Crustacea completely enclosed in a horny or calcareous
bivalve shell. Only seven pairs of appendages present — two of antennae, one of
mandibles, two of maxillae, and two pairs of thoracic feet. Abdomen short and

As a rule only the bivalve shell of the Ostracoda is found fossil, and since
the classification is based principally upon characters presented by the
appendages, the relations of recent to fossil forms cannot be made out with
certainty, especially as the form and ornamentation of the shell are largely
independent of the internal organisation.

The valves are closed by a sub-central adductor muscle, the attachment of
which is marked on their inner sides by a tubercle, pit, or a number of small
spots. The shell is compact in structure, commonly from 1 mm. to 4 mm. in
length, although sometimes exceeding 20 mm. The outer surface may be

1 Literature :

Bosquet, J., Description des Entomostraces fossiles de la craie de Maestricht (Mem. Soc. Roy.
Sci. Liege, IV.), 1847. — Description des Entomostraces fossiles des terrains tertiares de la France et
de la Belgique (Mem. Couronn. Acad. Roy. Belg., XXIV.), 1850. — Monographic des Crustaces
fossiles dn terrain cretace du Duche de Limburg (Mem. Commiss. Carte geol. Neerlande). Haarlem,
1854. — Reuss, A. E., Die fossilen Entomostracen des osterreichen Tertiarbeckens (Haid. naturw.
AbhandL, III. Pt. 1), 1850. — Die Foraminiferen und Entomostracen des Kreidemergels von Lemberg
(ibid. IV., Pt. 1), 1851. — Jones, T. R., A Monograph of the Entomostraca of the Cretaceous Forma-
tion of England (Palaeont. Soc.), 1849. — Idem, and Hinde, G. J., A Supplemental Monograph of
the Cretaceous Entomostraca of England and Ireland (ibid.}, 1890. — Jones, T. R., A Monograph of
the Tertiary Entomostraca of England (ibid.), 1857. — Idem, and Sherborn, C. D., A Supplemental
Monograph of the Tertiary Entomostraca of England (ibid.), 1889. — Jones, T. R., and Kirkby, J. W.,
Notes on Palaeozoic bivalved Entomostraca, Nos. 1-32 (Ann. Mag. Nat. Hist.), 1855-95. — Eyger, 0.,
Die Ostracoden der Miocanschichten bei Ortenburg (Neues Jahrb. p. 403), 1858. — Speyer, 0. W. C.,
Die fossilen Ostracoden aus den Casseler Tertiarbildungen (Cassel Jahresber., vol. XIII.), 1863. —
Brady, O. S., Crosskey, H. W., and Robertson, D., A Monograph of the Post-Tertiary Entomostraca
of Scotland (Palaeont. Soc.), 1874.— Jones, T. R., Kirkby, J. W., and Brady, G. S., A Monograph
of the British Fossil bivalved Entomostraca from the Carboniferous Formations (ibid.), 1874, 1884.
— Jones, T. A., and Holl, H. B., Notes on Palaeozoic bivalved Entomostraca (Ann. Mag. Nat. Hist.
[4], III.), 1869. — Brady, G. S., and Norman, A. M., A Monograph of the marine and fresh-water
Ostracoda of the North Atlantic, etc. (Sci. Trans. Roy. Dublin Soc., IV., V.), 1889-96.— Lienenklaus,
E., Monographic der Ostracoden des nordwestdeutshen Tertiars (Zeitschr. deutsch. geol. Ges., XLVI.),
1894. — Jones, T. R., and Kirkby, J. W., On Carboniferous Ostracoda from Ireland (Sci. Trans. Roy.
Dublin Soc., VI.), 1896.— Ulrich, E. 0., The Lower Silurian Ostracoda of Minnesota (Geol. Minn.,
III. Pt. 2, Palaeont.), 1897.— Sherborn, C. D., The literature of fossil Ostracods (Nat. Sci. X.), 1897.

SUPER-ORDKK 111 OSTRACODA

smooth and glossy, or granulose, pitted, ruticiilo.se, striate, hirsute, or other-
wise marked, the effect being often quite ornamental. The two valves may
be of equal size (Beyrichia), or more or less unequal, with either the right oc
left valve overlapping at the ventral border only (///'y /•'//'//</), or at thu dorsal
border as well (BairdiO,\ or in some cases overlapping all round (f ///////••

Most commonly the outline is ovate or reniform ; in many cases, however,
one or both ends may be pointed or drawn out in the form of a beak ; and
when the dorsum is straight, the ends may join it angularly. Although
usually convex, the ventral margin is sometimes straight or gently concave.
It is sometimes impossible to distinguish between anterior and posterior
extremities, but as a rule the posterior half is somewhat thicker than the
other, even though of equal or of lesser height. The hinge line may In-
straight or arcuate, the hinge itself being generally simple, although among
the Cijtherklae hinge teeth and corresponding sockets are often develoj >»•<!.
There are commonly a small median and two larger lateral eyes • the position
of the latter being often indicated on the exterior of the valves by a small
" eye tubercle," or ocular spot.

Save for one or two families (Cypridae), Ostracods are almost wholly
restricted to marine or brackish water. They are gregarious, and occur in
vast hordes swimming near the surface or creeping over the bottom, preferring
usually shallow depths. Their remains abound in nearly all the leading
formations, and are often important rock - builders. The identification of
fossil Ostracods is very difficult on account of their similarity of form and
ornamentation, and usually minute size ; and they cannot be well intercalated
among the recent series for reasons already given. An arrangement of the
families into higher groups is not attempted here, and only the more
representative genera can be noticed.

Family 1. Leperditiidae. Jones.

Thick-shelled Ostracoda, mostly of considerable size. Valves smooth and glossy, of
very compact structure, and in general regularly convex; hinge line straight; anterior
and posterior ends obliquely truncated or rounded, and neither gaping nor excised.

Leperditia, Renault (Fig. 1337). Shell sub-oblong with an oblique backward
swing, from 2 mm. to 22
mm. long ; dorsal edge
straight, generally an-
gular at the extremities ;
ventral outline roun<l»-d.
Valves unequal, the

right larger and overlap- Flo. 13SS>

ping ventral edge of the '•'"•• 1337. /,.,„.;,,> iioemer.

e

left. Surface often » * ....... «• «n«ta' ^ft.

corneous n appearance,

smooth, and eye tubercle generally present on the antero-doreal quarter. A large

rounded sub-central muscular imprint present on interior. Ordovician to Carboniferous.

Leperditelia, Ulrich. Similar to above, but the left instead of right valve is the
larger, and has a groove within its ventral border for receiving simple edge of the
right. Eye tubercle wanting. Length 1 mm. to 3 mm. Ordovician.

Isochilina, Jones (Fig. 1338). Like Leperditia except that the valves do not over-
lap but are equal in every respect. Ordovician and Silurian.

644

AKTHKOPODA

SUB-KINGDOM VII

Aparchites, Jones. Shell not over 3 mm. in length, equivalve, sub-ovate or oblong ;
ventral edge thickened, often bevelled. Ordovician and Silurian.

FIG. 1339.

Primitia prunella, Barr.
Silurian (E) ; Konigshof,
Bohemia (after Barrande).

Family 2. Beyrichiidae. Jones.

Small equivalve Ostracoda with a long straight hinge. Shells vertically sulcated and
more or less lobate, varying from forms having a simple median depression to others in
which the surface of the valves is raised into numerous low lobes, ridges or nodes.

Primitia, Jones and Holl (Fig. 1339). Valves ovate or oblong, ventral margin
rounded, not over 2 mm. long. Well-marked sub-central pit or sulcus, with furrow
extending to hinge line. Cambrian to Carboniferous.

Dicranella, Ulrich. Differs from Primitia in having long
horn-like diverging prominences on one or both sides of the
central sulcus. Ordovician.

Aechmina, Jones and Holl. Like Primitia, but having
instead of the sulcus a single, sometimes enormously developed
horn-like process. Ordovician to Devonian.

Eurychilina, Ulrich. Oblong or semi - elliptical shells
having a sub -central Primitian sulcus, the posterior edge of
which is often raised in to a small rounded node. Anterior,
ventral, and posterior margins provided with a wide, often radially marked frill-like
border. Ordovician.

Kloedinia, Jones and Holl. Intermediate between Primitia and Beyrichia. Its
more or less well-defined small lobe between
the two sulci represents the median lobe
of Beyrichia. Ordovician to Devonian.

Beyrichia, M'Coy (Figs. 1340, 1341).
Typically the valves have three lobes or
nodes, of which the central one is the
smallest, and commonly quite isolated from
the other two. The outer ones are some- -
times connected ventrally, and are not Brandenburg,
infrequently broken up into sets of smaller
nodes ; occasionally all of them are united below. Ordovician to Carboniferous.

Tetradella, Ulrich. Valves marked by four more or less curved vertical ridges
which are ventrally united ; one or both of the inner ridges sometimes duplex, or all
four may be split up into separate nodes. Ordovician and Silurian.

Ceratopsis, Ulrich. Distinguished from the last by the remarkable process which
arises from the extremity of posterior ridge. This may be straight and horn-like with
one of the edges toothed, or expanded. Ordovician.

Bollia, Jones and Holl. Valves with a central looped or horseshoe-shaped ridge,
the free upper extremities of which are often bulbous. Ordovician to Carboniferous.

Drepanella, Ulrich. Valves depressed convex, sub-oblong, with a more or less com-
plete, often sickle-shaped, sharply elevated marginal ridge, within which the surface
exhibits two or more usually distinct nodes. Ordovician.

FIG. 1340.

FIG. 1341.

Beyrichia Bohemica,
Barr. Ordovician;
Vinice, Bohemia.

Family 3. Cytheridae. Zenker.

Minute shells of generally elongate-oval, reniform, or sub-quadrate outline, and of
dense structure. Surface smooth, punctate, nodulose, striate or spinose ; hinge generally
denticulated, the right valve with two teeth in most cases, and the left with corresponding
pits.

SUPER-ORDKH III

OSTHACODA

64fl

Cythere, Miiller (Figs. 1342, 1343). Sh.-ll ivnil'..nn or sub- quadrat.-, n-u;illy
widest in front ; sui -fa. ••• A

ornamented with punctae,
nodes, spines, and ridges ;
hinge teeth strong, placed
one at each end of a Imri-
xontal bar wliicli fits into a
corresponding furrow and
sockets of the left valve.
In the sub-genus Cythereis,
Jones (Fig. 1344), the con-
necting bar of the hinge is
wanting. Cretaceous to
Recent.

Cytheridea, Bosq. (Fig.
1345). Differs from Cythere in having hinge beset with row of small teeth in right

Fl<;. 134'-'.

Cyt)i- . KIM-HI. s|,.

Miocene; Leognan, nwir Hor-
cleaux. -"-Y! (after Bosqu.-t).

1343.

nrian.

.lor.l:ili Hi;:

laml. .1. Int'-rior of left valve.

/;, Exterior of ri-ht valve, en-
larged (aft«r Bra-ly).

FIG. 1344.
Cythereis quadrilatera, Roemer. Gault ; Folkestone. <25/i (after T. Rupert Jones).

valve, often interrupted in the middle, and with corresponding pits in the left. Jura
to Recent.

Cytherideis, Jones. Shell more or less triangular. Surface
smooth, pitted or tuberculate ; hinge simple. Cretaceous to
Recent.

Family 4. Thlipsuridae. Jones.

Minute, reniform, or ovate inequivalve shells, the margin of one
FIG. 1345. valve overlapping that of the other more or less completely ; dorsal

"Bocemr mar9^n arcuate, ventral sometimes straight or slightly sinuate.
Coiweii Bay, England. Surface with two or more definite pits.
22/! (after Jones).

Thlipsura, Jones and Holl. Each valve generally witli three
pits, one posterior and two in the anterior half. No ornament. Silurian.

Octonaria, Jones. Differs from the last in having the surface of valves raised into
a thin spiral or annular ridge which in more typical forms is 8 -shaped. Silurian and
Devonian.

Phreatura, Jones and K. Distinguished from Thlipsura by the strong compression
of posterior end of shell, which is further marked by a shallow semicircular pit ; a
similar but smaller pit present at anterior extremity. Carboniferous.

Family 5. Cypridae. Zenker.

Minute, mostly reniform or elongate-ovate, corneous or corneo-calcareous shells, with
thin, somewhat unequal valves, one overlapping the other either ventrally or dorsally or
loth.

Recent Cypridae are chiefly fresh-water inhabitants, but this is true in a leaser
degree of the fossil forms. All the Palaeozoic representatives are marine, excepting

646

ARTHROPODA

SUB-KINGDOM VII

perhaps certain Carboniferous species. Fossil remains are extraordinarily profuse in
certain deposits, and the family is an important rock-builder.

Palaeocypris, Brongt. Shell 0'5 mm. long, sub-ovate, smaller posteriorly than in
front ; surface granulose and finely hirsute in dorsal region. Carboniferous.

Mtiller (Fig. 1346). Shell reniform or oval, thin, translucent, smooth or
hirsute, often punctate; hinge edentulous, somewhat
thickened; ventral margin often sinuate. Tertiary to
Eecent.
c Cypridea, Bosq. (Fig. 1347). Like Cypris, but with

FIG. 1346.

Cypris faba, Desm. Miocene;
Oeningen, Switzerland. A, Side, and

B, Dorsal view, is/j (after Bosquet).

C, Valves composing fresh -water
limestone at Nb'rdlingen.

FIG. 1347.

Cypridea Waldensis,
Sowb. Wealden ; Ober-
kirchen, Hanover. l*/j.

FIG. 1348.

Bairdia curta, M'Coy.
Carboniferous Limestone ;
Ireland. 15/X (after
Kirkby).

small hook-like projection at the antero- ventral angle. Purbeck and Wealden.

Bairdia, M'Coy (Fig. 1348). Shell sub-triangular or rhomboidal, with the
greatest height near the middle, generally smooth, both extremities narrowly rounded
or pointed. Dorsal margin more or less strongly convex ; hinge formed by overlap-
ping edge of left valve. Ordoviciaii to Recent ; maximum in Carboniferous.

Bythocypris, Brady. Shell smooth, reniform, ovate or elliptical ; left valve over-
lapping the smaller right valve usually on both dorsal and ventral margins. Typically
Recent, but a number of Palaeozoic forms have also been assigned to this genus.

Macrocypris, Brady. Similar to the last, but generally more elongate, posteriorly
more acuminate, and right valve larger than the left. Ordovician and Silurian ;
Jurassic to Recent.

Pontocypris, Sars. Like Bythocypris, except that shell is very delicate, and hinge
simple without overlap. Silurian, Carboniferous, Pleistocene, and Recent.

Family 6. Cytherellidae. Sars.

Family characters chiefly zoological. Shell minute, inequivalve, thick, calcareous, not
notched anteriorly.

Cytherella, Jones (Fig. 1349). Shell oblong or sub-ovate, compressed in front;
surface generally smooth, but sometimes undulating and marked
with pits and granules. Contact margin of the larger right valve
grooved for reception of flange -like edge of smaller left valve.
Ordovician to Recent.

Cytherellina, Jones and Holl. Silurian. ? Pachydomella,
Ulrich. Devonian. Bosquetia, Brady. Recent.

Family 7. Entomidae. FIG. 1349.

Cytherella cmnpressa,

Shells relatively short, strongly convex, reniform, ovate or rounded Munst. sp. oiigocene ;
quadrate, sub-equivalve, with a more or less well-marked depression near 22/jp(after°Bosquetf mi
the middle of dorsal region. Surface sculpture concentric or radiate.

Entomis, Jones (Figs. 1350, 1351). Shell sub-ovate or fabiform ; valves with a
slightly curved sub-median vertical furrow extending to hinge line ; in front of furrow
occasionally a rounded tubercle. Surface marked generally with raised, concentric,

SUPER-ORDER III

OSTRACODA

847

transverse or longitudinal lines. Oi-lo\ i, i,,n to Carboniferous; very profuse in
Devonian.

Entomidella, Jones. Likr
Entomis, but with furrow extending
entirely across the valves to ventral
edge. Cambrian to Silurian.

Elpe, Barr. Shell ivnil<.rm,
3 nun. to 7 mm. long, with depres-
sion just behind the middle of dorsal
slope ; posterior half sometimes
strongly inflated. Delicate radial
ornament. Ordovician and Silurian.

Fio. 1351.

Family 8. Cypridinidae. Sars.

Fio. 1350.

I pelagica, Barr.
Lower Devonian (F);
Konieprus, Bohemia.

/•;///<, /in'.-- .•"i-nito-iitriata, Sandb.
sp. Upper Devonian ; WeilhurK,
Nassau. A, Fragment of matrix,
Vl. B, \Vntral and lateral aspect*,
B/I. C, Impression of valve, >/i.

Shells equivalve, sub-elliptical to
oblong, convex, smooth or punctate,
and sometimes ribbed, especially in posterior half. Anterior end with a notch and hook-
like hood overhanging an opening left between edges of valves for protrusion of the lower
antennae ; posterior extremity frequently acuminate.

Cypridina, Milne-Ed\v. (Fig. 1352). Shell generally acuminate, oviform, rarely
oblong ; antero-dorsal edge projecting beak-like over the strongly defined notch ;
muscle spot large, sub-central, often visible on exterior. Ordovician to Recent

Cypridinella, J. K. and B. Like Cypridina, but having the antero-ventral region
projecting somewhat prow-like and generally beyond the hook. Carboniferous.

Fio. 1352.

Cypridina primaeva, de Kon.
sp. Coal Measures ; Braid-
wood, England. 4/i (after J.
K. and B.).

Fio. 1353.

Cypridella Wrigktii, J. K. B. Carbon-
iferous Limestone ; Cork, Ireland. 8/, (after
J. K. and B.).

Fio. l.v,;.

CypreUa chrysalidea, de
Kon. Carboniferous
Limestone ; Cork, Ire-
land. •»/! (after J. K.
and B.).

Cypridellina, J. K. and B. Differs from the last in having a tubercle or lump
above the centre of the valve. Carboniferous.

Cypridella, de Kon. (Fig. 1353). Like Cypridellina except that it has a curved
sulcus behind the tubercle. Carboniferous.

CypreUa, de Kon. (Fig. 1354). Shell much as in the last, but annulate. Carboni-
ferous.

Sulcuna, Rhombina, J. K. and B. ; Cyprosis, Cyprosina, Jones. Palaeozoic.

Family 9. Entomoconchidae.

Shell sub-globose, more or less inequivalve ; front edge truncate and icith central
portion of margin inturned so as to leave a simple or sinuate slit. Beak not developed.

Entomoconchus, M'Coy ; Offa, Jones, Kirkby and Brady. Carboniferous.

Geological Range of the Ostracoda.

Undoubted Ostracoda are first met with in the Upper Cambrian, and certain
problematical remains indicate that they were initiated even earlier. Their post-

648 ARTHROPODA SUB-KINGDOM vn

Cambrian evolution was very rapid, and during the Ordovician they nourished as
greatly as at any subsequent period. The prevailing Ordovician and Silurian types
belong to the Leperditiidae and Beyrichiidae, although toward the close of the Silurian
numerous Cypridae make their appearance.

Devonian Ostracoda are less numerous, but manifest essentially the same types as
in the earlier periods. Here, however, the larger Leperditiidae are entirely wanting.
Although many small species of archaic genera persist in the Carboniferous, the aspect
of the fauna is changed by the strong development of Cyprinidae. Thereafter but a
meagre representation of Ostracods is met with until the Cretaceous, when certain
genera, especially Cythere, develop a surprising variety and wealth of species. Little
difference can be detected between Tertiary Ostracods and their modern descendants.

[The above generic diagnoses of Ostracoda have been abridged from a more extended dis-
cussion of the group, prepared for this work by Mr. E. 0. Ulrich, of Newport, Kentucky. —
TRANS.]

Super-Order 4. CIRRIPEDIA. Barnacles. Latreille.1

Sessile, mostly hermaphroditic animals, enclosed in a membranous mantle which
is often covered ivith calcareous plates. Body attached by the anterior extremity of the
head ; obscurely, and at times not at all segmented ; posterior portion with at most
six pairs of divided legs or cirri, which, however, may be fewer in number or altogether
absent.

The typical and best known Cirripedes (Balanidae and Lepadidae) differ so
widely from all other Crustacea in their external form, solid calcareous shells,
slightly developed respiratory and sensory organs, and especially in their
hermaphroditic sexual apparatus, that until 1830 they were commonly classed
with the Mollusca. About this time J. V. Thompson and Burmeister showed

1 Literature : A. Recent Forms.

Thompson, J. V., Zoological Researches and Illustrations. I. Cork, 1830. — Discovery of the
Metamorphosis in the Lepades, etc. (Phil. Trans. Roy. Soc., Pt. 2), 1835.—Burmeister, H., Beitrage
zur Naturgeschichte der Rankenfiissler. Berlin, 1834. — Martin- Saint- Ange, G. J., Memoire sur
1'organisation des Cirripedes (Mem. Savans. ]£trang. Acad. Sci. Paris, VI.), 1835. — Darwin, C.,
A Monograph of the Sub-Class Cirripedia (Ray Soc., I., II.), 1851-54.— Hoek, P. P. C., Report on
the Cirripedia (Kept. Challenger Exped., Zool., VIII. , X.), 1883-84.— A urwillius, C. W. S., Studien
iiber Cirripeden (K. Svensk. Vetensk. Akad. Handl., XXVI., No. 7), 1893.— Groom, T. T., On the
Early Development of the Cirripedia (Phil. Trans. Roy. Soc., 185), 1894.— Hansen, H. J., Phyllopoda
and Cirripedia. Plankton Expedition, 1895.

B. Fossil Forms.

Sowerby, J., and J. de C., The Mineral Conchology of Great Britain. London, 1812-30.—
Roemer, F. A., Die Versteinerungen des norddeutschen Kreidegebirges. Hanover, 1840-41. —
Darwin, C., A Monograph of the Fossil Lepadidae of Great Britain (Palaeont. Soc.), 1851. — A
Monograph of the Fossil Balanidae and Verrucidae of Great Britain (ibid.), 1854. — Bosquet, J.,
Monographic des Crustaces fossiles du terrain cretace du Duche de Limbourg (Mem. Commiss. Carte
geol. Nederlande), 1854. — Notice sur quelques Cirripedes recemment decouverts dans les terrains
cretace du Duche de Limbourg. Haarlem, 1857. — Reuss, A. E., Ueber fossile Lepadiden
(Sitzungsber. Akad. Wiss. Wien., XLIX.), 1864.— Woodward, H., On Turrilepas, etc. (Quar. Journ.
Geol. Soc., XXI. ), 1865.— Barrande, J., Systeme Silurien du centre de la Boheme., I. Suppl. 1872.—
Seguenza, G., Ricerche palaeontologiche intorno di Cirripedi terziarii della Provincia di Messina,
Pts. I., II. Naples, 1873-76. Marsson, J., Die Cirripeden und Ostracoden der weissen Schreib-
kreide der Insel Riigen (Mittheil. naturw. Ver. Neu-Vorpommern und Riigen, XII.), 1880. — Zittel,
K. A., Bemerkungen iiber einige fossilen Lepaditen aus dem lithographischen Schiefer und der oberen
Kreide (Sitzungsber. Bayer. Akad. Wiss., XIV.), 1884.— Faber, C. L., Remarks on some Fossils of the
Cincinnati Group (Journ. Cincin. Soc. Nat. ScL, IX.), 1887.— Hall, J., and Clarke, J. M., Palaeon-
• tology of New York, VII. p. 209, 1888.— Clarke, J. M., Notes on certain Fossil Barnacles (Amer.
Geol., XVII.), 1896. — Matthew, G. F., On occurrence of Cirripeds in the Cambrian (Trans. N. Y.
Acad. Sci., XV.), 1896.— Logan, W. N., Cirripeds from Cretaceous of Kansas (Kansas Univ. Quar.,
VI.), 1897.

SUPER-ORUKU IV

649

that these Cirripedes pass through a nauplius stage, and that directly before
attachment both Balamis and Lepas undergo a Cfyprw-stage, thus showing very
clearly their relation to the Eiicrustacea.

All Cirripedes are marine animals. Those with calcareous shells attach
themselves to stones, wood, mollusks, crabs, corals, and sea plants, and often
cover rocky coasts in myriad numbers. Some genera (('<>n>nnl>i, Chenolobia)
embed themselves in the thick skin of whales and dolphins ; some (Pyrgoma,
Palaeocreusia) bore into corals or shells of mollusks, and others lead a parasitic
existence in the abdominal cavity of Decapods or within the shells of other
Cirripedes. Most barnacles inhabit shallow water, but certain genera occur
at great depths, from 1900 to 2000 fathoms (Sealpellum, J'<mica). Many of
the living families are naked, and naturally only those possessing shells
(Tlioracica) have left fossil remains, although some of the tubular cavities in
molluscan shells may have been perforated by naked Cirripedes. Fossil
forms occur sparingly in the older strata, and do not become abundant until
near the close of the Tertiary.

Order 1. THORACICA. Darwin.

Body indistinctly segmented, and enclosed in a membranous mantle in which calcare-
ous plates are usually developed. Mostly hermaphroditic, sometimes with complemental
males.

Family 1. Lepidocoleidae. Clarke.

Body covered with two vertical columns of overlapping plates, those of one series
alternating with those of the other. Terminal or caudal plate axial. Basal or cephalic
portion of the body with a ventral curvature. Apices of the plates on the dorsal margin.
No accessory plates.

Lepidocoleus, Faber (Fig. 1355). Elongate, blade-shaped ;
dorsal edge the thicker, ventral edge sharper and linear. The
two series of plates make a complete enclosure, being inter-
locked on the dorsal edge, but are only in apposition on the

ventral edge, where they were un-

doubtedly capable of dehiscence for

the protrusion of the appendages.

Most primitive genus of the group.

Ordovician to Devonian.

FlG 1355

M >""'• ;. Clark.-.

Family 2. Turrilepadidae. Clarke.

ventral views.

FIG. 1356.
Turrilejxis Wrightianus, de

Body with four to six vertical

columns of triangular plates, two of the columns being siitnll,
accessory, and sometimes much modijied in shape. Caudal plate
patelliform, axial.

Turrilepas, Woodw. (Plumulites, Barr.), (Fig. 1356). Body
5ilcomnpie?eUSi- elongate-conical with four to six columns of large triangular
vicinal, i/j. ' R, c, isolated overlapping scales, some of which are keeled in the ini<Mli-.
plates, enlarged - Begideg having concentric striae, surface may be radially lined

or punctated. Cambrian (?) to Upper Devonian.

Strobilepis, Clarke. Composed of four columns of overlapping plates, two of winch
are of large and equal size. Of the other two intervening columns, one consists of a
few very small plates, and the other is modified into a series of grooved spines which

650

ARTHROPODA

SUB-KINGDOM VII

appear to overlap one another at their bases, and to lie opposite the column of small
plates. Caudal extremity terminated by a circular, conical, axial plate, against the
sides of which lies the first plate in each column. Middle Devonian.

Family 3. Lepadidae. Darwin. (Goose Barnacles.)

Shell pedunculated, composed mainly of the paired terga and scuta, the unpaired
carina, and a variable number of small calcareous plates, some of which cover the
flexible peduncle ; others take part in the capitn- SRC

lum. The calcareous plates are never fused.

Archaeolepas, Zittel (Fig. 1357). Peduncle

Archaeolepas Redten-
bacheri, Opp. sp. Litho-
graphic Slates ; Kel-
heim, Bavaria, l/i- C,
Carina ; R, Rostrum ;
S, Scutum ; T, Tergnm.

FIG. 1358.

A, Loricula laevissima, Zitt.
Senonian ; Diilmen, West-
phalia, l/i . £, C, L. Syriaca,
Dames. Cenomanian ; Le-
banon, i/! and 2/j.

FIG. 1350.

Pollit-ipes laevissimus, Quenst. Upper Cre-
taceous ; Liineburg, Belgium. C, Carina ; L,
Lateralia; R, Rostrum (?); S, Scutum. 1/1-

flattened, the two principal surfaces with four to six, the narrow sides with two
columns of small scales. The capitulum is com-
posed of triangular scuta, two large trapezoidal
terga, a short unpaired carina, and a minute
rostrum. Upper Jura.

Loricula, Sowb. (Fig. 1358). Peduncle
squamous. Capitulum with two scuta, two
terga, four lateralia, and a very narrow carina.
Cretaceous.

Pollicipes, Leach (Polylepas, Blainv.), (Fig.
1359). Capitulum composed of numerous (eigh-
teen to one hundred) plates, among which the
scuta, terga, rostrum, and
carina are distinguishable
by their size, Lateralia
generally in two columns.
Peduncle membranous
with minute scales.
Upper Jura to Eecent.

Squama, Stramentum,
Logan. Upper Cretaceous
(Niobrara) ; Kansas.

Scalpellum, Leach

(Figs. 1360-1362). Ca- ScalpellumGallicum>
pitulimi With twelve to Hebert. Upper Cretace-
fifteen pieces. Terga and
scuta much larger than
in Pollicipes and of very characteristic form. Carina narrow, long, with arched surface.
Peduncle covered with fine scales, rarely naked. Cretaceous to Recent.

FIG. 1360.

sc d U

FIG. 1361.

Capitulum of Scalpellum fossulum, Darwin.
Upper Cretaceous ; Norwich, England. 2/i-
C, Carina ; L, Laterale superius (upper latus) ;
R, Rostrum ; S, Scutum ; T, Tergum ; cl,
Carino - latus ; il, Infra - median latus ; rl,
Rostral latus ; sc, Sub-carina ; sr, Sub-rostrum
(after Darwin).

SUPER-ORDER IV

rih'IUPKDlA

Lepas, Linn. (Fig. i:w:ij. Peduncle naked. Capitnlum r,>nsi-tin^ «•!' ««nly t\v.,
very large triangular scuta, two small trrga, and a single carina. IMion-m- and Recent

Poecilasma, Darwin. Capitulum
consisting of three, five, or -evi-n
pieces. Carina extending only t<>
base of the terga, the latter somet inn-
wanting. Scuta sub -oval. Tertiary
and Recent.

Family 4. Verrucidae. Darwin.

Shells sessile and composed of si.i
pieces. Of the scuta and terga on I it one
is free, the other plate in each being
fused with the rostrum or carina.

The solitary genus Verruca,
Sclium., ranges from the Cretaceous to
Recent.

Family 5. Balanidae. Darwin.
(Acorn Barnacles.)

FlG- 1362-

PlO. 13.13.

Lepas anatifirtt, Linn.
Recent ; Mediterranean C,
P, Peduncle; S,
T, Terguin.

Carina ;
Scutun

Shell obtusely conical, circular, or
oval in cross section, with broad calcar-
eous cellular base ; composed of four to (after Darwin).
ten lateralia, more or less completely

fused at their sides, and two pairs of free terga and scuta which close the upper aperture
like an operculum.

Of the lateral plates which comprise the crown-shaped immovable test, two are
designated as carina and rostrum, the pieces lying between and occurring in pairs being

called lateralia. If additional plates are inserted
among the lateralia, they are termed according to their
position rostro- or carino -lateralia. The scuta and
terga lie free on the back of the animal, and in fossil

FIG. 1364.

Diagram of the shell of Ralanu*. B,
Basis; C, Carina; CL, Carino -lateral
compartment; L, Lateral compartment ;
R, Rostrum ; RL, Rostro-lateral com-
partment. Each valve or "comi>art-
inent " consists of a central " paries " (p)
flanked by " alae " (a) or " radii " (r).

FIG. 1365.

Scutum and terguin of llalnnus. A, External aspoct of t«>r>:<iin,
showing "spur" below and "beak" above. B, Internal view «(
scutum, showing muscular scar (x). C, Internal view of tergum
(after Darwin).

forms are generally lost. They have a very characteristic form, and hence are of
great systematic importance. Since among fossil species, however, only the marginal
plates are for the most part preserved, the determination of their structural characters
is often quite uncertain.

Balanus, Lister (Figs. 1364-1367). Shell low, conical or cylindrical, composed of

652

ABTHKOPODA

SUB-KINGDOM VII

six pieces. Opercular p]ates sub-triangular ; base membranous or calcareous. Eocene
to Recent.

Protobalanus, Whitf. Composed of twelve plates, of which the carina is the

largest ; rostrum small, lateralia
in five pairs, fused only near the
base. Middle Devonian.

Acasta, Leach. Shell com-
posed of six solid pieces. Base
calcareous, cup -shaped; attached
to sponges and Alcyonarians.
Pliocene and Recent.

Pyrgoma, Leach (Creusia,
Blainv.). Shell formed of a single
piece. Base cup - shaped or sub-
cylindrical ; attached to corals.
Lower Devonian. Tertiary and
Recent.

Palaeocreusia, Clarke (Fig.
1368). Shell in one piece, with
a deep cylindrical base ; attached

FIG. 1366.

Balanus concamis, Bronn. Crag ; Sutton, England. A, Shell.
B r Tergum. C, Scutum. 1/1 (after Darwin).

to corals. Lower Devonian.
Coronula, Lam. Composed of six lateralia, with thin, deeply folded walls dividing

FIG. 1367.
Balanus pictus, Miinst. Miocene ; Dischingen, Wiirtemberg.

FIG. 1368.

Palaeocreusia devonica, Clarke.
Embedded in Favosites. Corniferous ;
Le Roy, New York.

Base

the interior space into chambers which open at the lower side of the shell,
membranous ; parasitic on whales. Pliocene to Recent.

Chthamalus, Rauz (Euraphia, Conrad). Shell depressed, composed of six pieces.
Base membranous. Cretaceous, Miocene, and Recent.

Pachylasma, Darwin. Shell in the young with eight pieces, which afterwards become
six, or by coalescence of the lateralia are apparently reduced to four. Base calcareous.
Pliocene to Recent.

Super-Order 5. MALACOSTRACA. Latreffle.

Eucrustacea having, in recent forms, a constant number (twenty or twenty-one) of
segments. Cephalothorax composed of thirteen segments, and bearing the same number
of appendages. Abdomen distinct, heptamerous (except in the Phyllocarida), the
terminal joint being known as the telson.

Under this head are included the orders Phyllocarida, Stomatopoda, Decapoda,
and Arthrostraca, all of which have fossil representatives.

SUPER-ORDER v M A LACOSTRACA

Order 1. PHYLLOCARIDA. Packard. (I, Cl.uis.)

Body composed of jive cephalic, <'i<jl<t ////</•//*•/>, a ml /</•„ /„ ,;,//,/ «/«//////»///;/ .*><///

and thorax covered //// </ /A/// i-hitinous or partially calcified carapace, u-li>
may be in a single piece or divided into separate valves by a striiiylit, unart /minted,
single or double hinge. In front of the carapace is a narrow movable plate or /«.<//////' .
The head bears two pairs of antennae, ami »tnlh-<l compound < rack segments

with soft phyllopodifoi'm legs. Abdomen composed of annular ft
ends in a spinifoi'm caudal plate (telson) provided with lateral spines.

The recent genus Nebalia (Fig. 1370) is regarded by Packard and Glaus
as the surviving representative of ancient Crustacean types, very numerous
during the Palaeozoic, which had been previously classed with the Phyttopotln,
but more properly form a distinct group (Phyllocaridd) connecting the
Entomostraca with the Malacostraca. The genus is very generalised, combining
Copepod, Phyllopod, and Decapod-like features with other more fundamental
characters of its own. Upon it is based largely the definition of the order,
but some of the extinct families show structural differences from the living
type which will eventually require their removal from this association.

Cephalic appendages have not been satisfactorily determined in any fossil
species, although traces of them have been noticed in a few genera (Cryptozoe,
Oeratiocaris, Ehinocaris). In the absence of contrary evidence there is every
reason to suppose that the appendages of the head, thorax, and abdomen were
on the type of Nebalia, since there is such close correspondence in the form of
carapace, rostrum, and abdomen. Owing to the non-preservation of limbs,
distinctions within the group are based principally on variations in the
structure of the carapace, and in the number of body segments. Several
fossil genera (Echinocaris, Rhinocaris, Mesothyra) bear a distinct optic node or
pit, suggesting a sessile simple eye in contradistinction to the stalked faceted
eye of Nebalia. In these genera, also, large cuspidate masticatory organs
have been found, which were apparently attached only by means of muscles ;

1 Literature:

Salter, J. W., On some new Fossil Crustacea, etc. (Quar. Jotirn. Geol. Soc., XII. p. 26, XIX. \,.
75), 1856-62.— On New Silurian Crustacea (Ann. Mag. Nat. Hist., V. p. 153), I860.— Hall, J.,
Palaeontology of New York, III., 1859.— 16th Ann. Kept. N.Y. State Cabinet Nat. Hist. 1863.
— Woodward, H., On a new Genus of Phyllopodous Crustacea (Quar. Jouni. Geol. Soc., XXII.
p. 503), 1866.— Geol. Mag., IX. pp. 433, 563, 1872 ; IX. pp. 386, 444, 1882 ; II. pp. 345,
385, 460, 1885. — Clans, C., Ueber den Bau und die systematische Stellung von Nebalia (Zeitschr.
wissensch. Zool., XXII.), 1872. — Barrande, ./., Systeme Silurien du centre de la Boherae, I.
Suppl. 1872.— Whitfield, R. P., Notice of new Forms of Fossil Crustacea, etc. (Amer. Jouru. Sci.
[3], XIX.), 1880.— Clarke, J. M., New Phyllopod Crustacea from the Devonian (Amer. Journ. Sci.
[3], XXIIL), 1882.— New Discoveries in Devonian Crustacea (ibid. XXV.), 1883.— Ueber deutsche
oberdevonische Crustaceen (Neues Jahrb., I. p. 178), 1884. — On the Structure of the Carapace in
Rliinocaris, etc. (Amer. Nat., XXVII. p. 793), 1893.— 14th Kept. State Geol. N.Y. I., 1898.—
Packard, A. S., A Monograph of the Phyllopod Crustacea of North America (12th Ann. Kept. U.S.
Geogr. Geol. Surv. Terr.), 1883. — Beecher, C. K, Ceratiocaridae from the Upper Devonian Measures
(2nd Geol. Surv. Penn. Kept. PPP), 1884. — Jones, T. R.,&nd Woodward, H., Various Papers in Geol.
Mag., I.-X., 1884-94, and Reports 1-12 of Comm. on Fossil Phyllopoda Brit. Assoc. Adv. S.-i.. 1883-
95. — Novak, 0., Remarques sur le genre Aristozoe (Sitzungsber. bolmi. Akad. Wissensch. p. 239)
1885. — (Ibid. p. 674), 1886. — On Occurrence of a New Form of Discinocaris in Bohemia (Geol. Mag.
[3], IX. p. 148), 1892.— Sars, O. 0., Report on the Phyllocarida (Leptostraca) Rept. Challenger
Expedition, XIX., 1887.— Hall, J. and Clarke, J. M., Palaeontology of New York, VII., 1888.—
Whitjield, R. P., New Genus of Phyllocaridae (Bull. Amer. Mus. Nat. Hist., VIII.), 1896.— -Jones,
T. R., and Woodward, H., Monograph of the British Palaeozoic Phyllopoda (Phyllocarida, Packard),
Part III. (Palaeontogr. Soc.), 1898.

654

ARTHKOPODA

SUB-KIXGDOM VII

these are compared by Woodward with the gastric teeth of the lobster
(Fig. 1369).

Sub-Order A. NEBALIINA. Clarke.

Carapace folded, univalved, and rostrate.

Family 1. Nebaliidae. Baird.

Cephalic appendages Jive, thoracic eight, abdominal eight, terminating in two caudal
spines. No metamorphosis ; development direct.

Fi<;. 1369.

Gastric teeth of Echinocaris
punctata, Hall. Hamilton;
Pratt's Falls, New York. 1/1-

FIG. 1370.
Nebalia Geoffroyi, M. Edw. Recent ; Mediterranean.

Nebalia, Leach (Fig. 1370). Represented by a few species inhabiting shallow
waters of northern seas. Paranebalia and Nebaliopsis are also Recent and marine.

Sub-Order B. HYMENOCARINA. Clarke.

Nebalia-like forms with folded univalved carapace; rostrum wanting (?).

Body

Family 1. Hymenocaridae. Salter.

with eight to nine thoracic and abdominal segments, and six caudal spines in
three pairs.

Hymenocaris, Salter (Fig. 1371). Carapace narrow
in front, very broad posteriorly, convex ; surface smooth
or faintly lined. Cambrian ; Wales.

Jflibeiria, Sharpe. Arched, univalved bodies with
strong beaks, muscular scars and sub -cardinal ridge.
These fossils have been referred to the Phyllocarida,
Pelecypoda, and Gastropoda. There is no satisfactory
evidence of their Crustacean nature.]

Sub-Order C. CERATIOCARINA. Clarke.

', Wales! Carapace bivalved, with a median symphysis and a

free rostrum.

Family 1. Ceratiocaridae. Salter.
Carapace pod-shaped, smooth, and without eye-nodes.

Ceratiocaris, M'Coy (Entomocaris, Whitf.), (Fig. 1372). Valves of carapace elongate,
sub-ovate, or sub-quadrate, narrow in front, sub-truncate, but not incurved behind.

SUPER-ORDER v M A L.\< ( >STU ACA •;:.:.

Surface without nodes or carinae. Antennae (?) obscure ; supposed gastric teeth large,
cuspidate. Rostrum Ian. -dilate. Body Begim-nt.- t'«m-t.-rn ••!• HHMV, tour to seven ex-
tending beyond the carapace, -..m.- ..f tli.-ni with «>l»ruiv l.ram-hial ftppendlgn (vopodl ,
Telson long, spinosi- un
the edges ; two lateral
appendages or cercopods.
Abundant in Ordovician
and Silurian ; Europe and
North America. Jf\^J^ ^M &

Cardiolites, Nicl.. ^ ^^

Supposed tracks of Cera-
tiocaris (?). Silurian;
Scotland.

Caryocaris, Salter.

Carapace smooth, narrow, l/ffii

f ., • , fm 'locarispapilio, Salter. Ordovician; Lanark-

sub-acute in front, thick, jiff shi),.. ,,t AnfewMwifc; m, Mandible; r, Rostrum.

Abdomen unknown; y 1 1 Vi (after Woodward),

caudal plate with three
spines. Cambrian ; Wales.

Physocaris, Salter. Carapace bladder-shaped, pointed in front, bivalved (?), smooth.
Abdomen smooth ; telson longer than the cercopods. Silurian.

Lingulocaris, Salter ; Saccocaris, Salter. Very imperfect remains of Crustacean
bodies. Lingula Flags ; Wales.

Acanthocaris, Peach. Carapace small, with a blunt snout in front ; surface
smooth. Body segments numerous, seven exposed beyond the carapace. Telson long ;
cercopods short or rudimentary. Lower Carboniferous ; Scotland.

Xiphidiocaris, Jones and Woodw. (emend.). Known only by its long curved blade-
like telson. Silurian (Ludlow) ; England. (X. ensis, Salter.)

Cryptozoe, Packard. Carapace smooth, broadly rounded in front ; imperfectly
known. Coal Measures ; Illinois. (C. problematicus, Packard.) Probably congeneric
with the Carboniferous species, Ceratiocaris Oretonensis, and C. truncata, Woodw., in
which traces of four cephalic appendages have been found.

Colpocaris, Meek. Carapace smooth, with deep anterior marginal sinus and sharp
extremity. Caudal plate with three spines. Lower Carboniferous ; Kentucky.

Strigocaris, Vogdes (Solenocaris, Meek). Carapace narrow and elongate, with
longitudinally striated surface ; very imperfectly known. Lower Carboniferous ;
Kentucky.

Nothozoe, Barrande, may belong in this association. Ordovician ; Bohemia.

Phasganocarisj Novak. Known only from the abdomen and telson. Last segment
long, cylindrical, with strong articulation. Telson articulated to the cercopods by deep
sockets ; edges spinose. Surface scaly. Lower Devonian ; Bohemia.

Macrocaris, Miller. Carapace valves very narrow in front, broad behind, strongly
lineate. Body segments numerous. Lower Carboniferous ; Kentucky.

Family 2. Echinocaridae. Clarke.

Carapace elongate or oval, with nodes (muscular or segmental) in the cephalic region,
one of which in each valve may be ocular but bears no optic pit ; one or more lateral
carinae usually present. A free rostrum has been observed in some genera.

Echinocaris, Whitf. (Figs. 1369, 1373). Hinge short, carapace sub-oval, broad in
front, not incurved behind, no postero- lateral spinules ; a single sigmoid carina on each
valve, sometimes a small accessory ridge near the hinge. Surface punctate and pustu-
lose, no longitudinal striations. Of the body segments, six are exposed and bear small

656

ARTHROPODA

SUB-KINGDOM VII

spines on their surface and posterior margins. Telson and cercopods are spines of un-
equal size. Middle and Upper Devonian ; North America.

Pephricaris, Clarke (Fig. 1374). Carapace as in the last,
but without the lateral carinae. Margins provided with a
single row of long recurving spines. Three or four abdominal
segments protrude beyond the carapace, the last two having
a single pair of long spines. Upper Devonian ; New York.

Aristozoe, Barr. (Bactropus, Barr.). Carapace with cephalic
node well developed, but without lateral carinae. But one
abdominal segment known, and this is very long, cylindrical,
with an intricate hinge at the articulation with the caudal
spines. Telson a long spine with a row of spinules on each

lateral edge. Novak has
shown that of Barrande's
three species, Aristozoe
re gin a, Bactropus
longipes, and Ceratiocaris
debilis, the first repre-
sents the carapace, the
second the last abdominal
segment, and the third
the telson of one form,
A. regina. Devonian ;
Bohemia. Species re-
ferred to the same genus
have been described from
the Cambrian of North

Pephricaris hwripiiata Clarke. Chemung America and Devonian
Group ; Alfred, New York. 1/1 (after „ „,

Clarke). of Germany and Eussia.

Orozoe, Callizoe,
Silurian ; Bohemia. Zonozoe,

FIG. 1373.

Echinocaris punctatu, Hall sp.
Hamilton Group ; Pratt's Falls,
New York. 1/1 (after Beecher).

FIG. 1374

Barrande, are presumably allied to Aristozoe (Novak).
Barr., and Solenocaris, Young, are not Crustacean.

Eleutherocaris, Clarke. Carapace elongate-subquadrate, truncate in front, incurved
behind ; rostrate (?). Broad, obscure nodes in the cephalic region ; lateral carinae
single, anterior, and very short. Body segments unknown ; caudal plate with a
slender telson and cercopods of equal length. Surface of all known parts more or less
strongly tuberculated. Upper Devonian ; New York.

Ptychocaris, Novak. Valves elongate-subquadrate, posterior margin sloping or
slightly incurved. Cephalic region with a cluster of small nodes in
front, and two larger nodes behind. Lateral region with a single
long sigmoid carina. Surface striated with raised longitudinal
lines. Abdomen and tail unknown. Lower Devonian ; Bohemia.

Elymocaris, Beecher. Surface of carapace evenly convex,
smooth, without lateral carina ; hinge line long ; posterior
margin convex ; cephalic nodes obscure ; rostrum not observed.
Abdomen with two exposed segments ; caudal plate short, with
broad, convex, rapidly tapering telson and two cercopods,
setigerous on their inner margins. Middle Devonian ; New
York. Upper Devonian ; Pennsylvania.

Tropidocaris, Baecher (Fig. 1375). Carapace with truncate Warren, Penn. Carapace
posterior margins ; ocular node well defined, other cephalic nodes Hall and Clarke).
obscure ; rostrum narrow and ridged ; surface of valves with several

strong longitudinal carinae. Abdomen with two exposed segments, which are sub-cylindri-
cal and without spinules. Upper Devonian and Lower Carboniferous ; Pennsylvania.

FIG. 1375.

Tropidocaris Mcarinata,
Beecher. C h e m u n g ;

SUPER-ORDER V

MALACOSTRACA

667

Emmelezoe, Jones and W. Valves of carapace elongat--, naimu, ami with distinct
ocular node; other cephalic nodes wanting. Surface- with tint- longitudinal raised
striae. Abdomen unknown. Silurian.

Sub-Order D. RHINOCARINA. Clarke.

Carapace iirith a free rostrum and narrow median dorsal plate separated from, the
valves by a straight or slightly curving hinge at each side. Ocular nodes clearly defined,
with a distinct optic pit at the summit.

Family 1. Rhinocaridae. Clarke.

Valves articulated by interlocking at the single point where they come in contact.
Abdominal segments two to three. Posterior margin of carapace concave and spined.

Bhinocaris, Clarke (Fig. 1376). Carapace smooth, with tine raised longitudinal
striae; divergent, branching furrows radiating back-
ward from the eyes. Lateral carina very faint.
Abdomen with two or three free segments, the last
much longer than the others ; all diagonally striated
or chevroned. Caudal plate with a broad telson and
two long and

A B

slender cercopods
fimbriated on
their margins.
Middle Devonian;
New York.

M e s o t h y r a,
Hall and Clarke
(Fig. 1377).
Carapace large,
valves distinctly

interlocking at Eye? B, Hinge of ri-ht valve.

point of contact.

Lateral carinae strong, crenulated at the summit, Abdomen with two broad, exposed
segments. Telson shorter than the cercopods, the latter setigerous. Upper Devonian ;
New York.

•;l.:«v •-..ir.iLrfi:.^

FIG. 1377.

Mi-rintliii-ii Vri'nn!, Hall. Portage Group
(Upper Devonian) ; Ithaca, New York. A,

FIG. 1376.

/'//(' rtocori* columbina, Clarke. Ham-
ilton Group; Canandaigua Lake, NI-W
York. A , E, Dorsal and lateral views of
animal. />', I), Same of rostrum, en-
larged. C, Median plate, enlarged.

Dithyrocaris, Scouler (Argas, Scouler). Very similar in aspect to Mesothyra,
with the junction line of the valves overlapped by a (free ?) rugose ridge or narrow
interstitial plate. Rostrum not observed. Devonian and Carboniferous ; Scotland.
Rachura, Scudder, known only from the abdomen and telson, is probably allied t<>
Dithyrocaris. Carboniferous; Illinois.

Chaenocaris, Jones and W. Carapace valves with a very strong lateral ridge and
without posterior spine. Carboniferous ; Scotland and Belgium.

Sub-Order E. DISCINOCARINA. Clarke.

Sub-circular or oval shields with a triangular rostrum filling an anterior notch
Surface ornamented with raised concentric lines. Substance chitinous.

VOL. I - 2 U

658

ARTHROPODA

SUB -KINGDOM VII

Family 1. Discinocaridae. Woodward.
Test convex, sometimes mesially ridged ; in a single piece.

Discinocaris, Woodw. Shield sub-circular, rostral notch, and rostrum angular.
Abdominal segments and caudal spines have been referred to this
genus by Jones and Woodward. Silurian; Great Britain,
Bohemia.

Aspidocaris, Eeuss. Similar to Discinocaris. Raibl Beds
(Trias); Hallstadt.

Dipterocaris, Clarke (Fig. 1378). Shield with a deep posterior
notch, shorter than the anterior or rostral notch. Sides of shield
sloping. Silurian ; Scotland. Upper Devonian ; New York.

FIG. 1378.

Dipterocaris vetustus,
d'Arch. and Vern. De-
vonian ; Eifel. 1/1-

Salter.

notch and plate.

FIG. 1379.

Aptychopsis primus,
Barr. Ordovician (D) ;

Family 2. Peltocaridae.

Shields mesially sutured.

Peltocaris, Salter. Circular shields with a rounded rostral
Abdomen unknown. Ordovician ; Great Britain.

Aptychopsis, Barr. (Fig. 1379). Like Peltocaris, but with the
rostral notch angular. Silurian ; Bohemia and Great Britain.

Pinnocaris, Etheridge. Similar to Dipterocaris, but bivalved.
Ordovician ; Scotland. (P. Lapworthi, Etheridge jun.)

Addendum.

A number of generic names, such as Gardiocaris (Fig. 1380),
Ellipsocaris, Pholadocaris, Woodward, and Spathiocaris, Clarke,
have been applied to Devonian fossils which closely resemble the Silurian Discinocaris,
of whose Crustacean nature there seems to be no doubt. Some of
these bodies, however (Cardiocaris), have been found in the living
chamber of Goniatites (G. intumescens), and have undoubtedly
served as opercula or aptychi of these Cephalopods ; of others
the nature is not fully understood. Lisgocaris, Clarke, is not a
Crustacean ; Cryptocaris, Barrande, is probably the operculum of
a Hyolithoid ; Myocaris, Salter, is stated to be a Pelecypod ;
Proricaris, Baily, was founded on parts of Ceratiocaris; Grescen-
tilla and Pterocaris, Barrande, are doubtfully Crustacean.

FIG. 1380.
Cardiocaris (At

ipty-

. >w -, [The authorship of the foregoing chapters on Phyllopoda, Cirripedia,

Upper WD?von fan'; and Phyllocarida, as well as the succeeding one on the Acerata (Mero-
Budesheim, Eifel. Vi- ' stomata), should be accredited to Dr. John M. Clarke, New York State
Palaeontologist. A number of additional figures for illustrating these
sections have also been prepared by him expressly for this work, or borrowed from his
previous writings. — TRANS.]

Order 2. SCHIZOPODA. Latreille.1

Small, elongated, aquatic Malacostraca with compound eyes borne on movable stalks,
and a large delicate carapace covering the thoracic segments more or less completely ; with

1 Literature:

Jordan, H., and Meyer, H. v., Crustaceen der Steinkohlenformation von Saarbriicken (Palaeontogr.,
IV.), 1856.— Salter, J. W., Higher Crustacea from British Coal Measures (Quar. Journ. Geol. Soc.,
XVII.), 1861. — Ethe,ridge, R., Occurrence of Anthrapalaemon in Carboniferous of Scotland (ibid.
XXXIII.), l877.— Whitfteld, R. P., New Crustacea from the Devonian of Ohio (Amer. Journ. Sci.
[3], XIX.), 1880. Also in Ann. N.Y. Acad. Sci., V., 1891.— Peach, B. N., New Crustacea from the
Carboniferous of Eskdale (Trans. Roy. Soc., Edinburgh, XXX., pp. 73, 512), 1880.— Brocchi, P.,
Note sur un Crustace, etc. (Bull. Soc. Geol. France [3], VIII.), 1880.— Packard, A. S., On the

si I>I:K-<>KI>I:I; v

MALACOSTi;.\r.\

859

Fio. 1381.

eight pairs of thoracic feet, which are similarly formed, provided with an exopodi
in one family (Mysidae] bear freely project in </ <////>.

The Schizopods bear a nupuTi'-i;il n>.Miil.l;tiicc to the macruroua Decapoda, and
were formerly united with thai <.r<ln-. Two principal
groups are distinguished, the Myaid and Euphausid,
which by some authors are elevated into indt •jH-mli-nt
orders. A few fossil remains have been, with some
colour of probability, assigned to tin- Schixopoda, such
as Pygocephalus, Huxley, from the English Coal
Measures, and Crangopsis, Salter (Palaeocrangon, Salter
non Schauroth ; Archaeocaris, Meek), from the Lower
Carboniferous of Scotland and base of tin- \Vavn-ly in
Kentucky. Pygocephalus also exhibits many Stomatopod
features.

Anthrapalaemon, Salter (Fig. 1381), from the Coal
Measures of Scotland and Illinois, and Palaeopalaemon,
Whitfield, from the Devonian of Ohio, are of doubtful
position, but more properly classed with the Schi/opods
than Decapods. The former genus has a curiously sub-
divided telson, a toothed anterior margin of the carapace,
and biramous antennae. Palaeopemphix, Paraprosopon, Anthrapalaemongraciiis,'&i.ai}'\\\.
and Oonocarcinus, Gemmellaro, from the Permo-Carbon- gjj i^JSJ'ieSfSnrortJS*'
iferous of Sicily, are for the most part fragmentary

remains, but without any decided Decapod features. The same is true of Pseudo-
galathea, Peach, from the Lower Carboniferous of Scotland.

The family Nectotelsonidae of Brocchi comprises a few Carboniferous and Permian genera
whose relations to the recent Anaspides have been suggested by Caiman. These are : Palaeo-
caris, Meek and Worthen ; Uroncctes, Bronn (Gampsonyx, Jordan), (Fig. 1382) ; and
Nectotelson, Brocchi (but not Acanthotelson, M. and W.). They show a number of characters
common to all Malacostraca, but no typical characters of any one
order. Anaspides, Thomson, living in the mountains of Tasmania,
agrees with the extinct genera in the combination of Podophthalmate
characters with a completely segmented body and the lack of a
carapace ; and while having its nearest affinities with the Schizopods,
is also closely related to the Amphipods.

The proposal to erect a separate order (Syncarida, Packard) for
this family, including Anaspides, seems hardly advisable, although it
is plain that many collective characters are here displayed. These
peculiar fossil forms indicate that a differentiation of Thoracostraca and
Arthrostraca took place as far back as the Upper Devonian, but dis-
tinctive ordinal features are not manifested until much later. [The
term Thoracostraca ( = Podophthalma} is used throughout this section
to connote the Schizopods, Stomatopods, and Decapods under one
head, as distinguished from the sessile-eyed Amphipods and Isopods.]

Order 3. STOMATOPODA. Latreille.1

Gampsonyx flmMattu,
Jordan. Rotliliegendes ;
Lebach, near Saar- Elongated Malacostraca, in which the compound stalked eyes and

uc en' first pair of antennae are borne upon distinct movable segments.

Carapace small, leaving the last four thoracic segments uncovered. There are Jive pairs

Syncarida, Gampsonychidae, and Anthracaridae (Mem. Nat. Acad. Sci., III.), 1885. Also in Proc.
Boston Soc. Nat. Hist., XXIV., 1889.— Caiman, W. T., On the Genus Anaspides, etc. (Trans. Roy.
Soc., Edinburgh, XXXVIII.), 1896.— Ortmcim, A. /•:.. The Systematic Position of Crangopsis, etc.
(Amer. Journ. Sci. [4], IV.), 1897.

1 Literature :

Munster, G. Graf zu, Beitrage zur Petrefaktenkunde (Heft. III. p. 19 ; V. p. 76), 1840-42.—
von der Mark, W., and Schltiter, C., Neue Fische und Krebse aus der Kreide von Westphalen

660

ARTHBOPODA

SUB-KINGDOM VII

of maxillipeds, the second pair being developed into large raptorial limbs, and three pairs
of biramous thoracic feet. Abdomen very strongly developed, longer than the anterior part
of the body, and its swimming feet bear branchial tufts.

The Stomatopods comprise a single family (Squillidae') of nine recent and still
fewer fossil genera, with the characteristics of the order. Living forms are inhabitants

of tropical and temperate waters
of both hemispheres, and prey
upon other animals. The oldest
fossil form is Necroscylla IVilsoni,
Woodward, from a concretion in
the Coal Measures of Cossall,
England. It is founded upon
an abdominal fragment 21 mm.
long, showing five segments and
a well-preserved telson, and bears,
some resemblance to the abdomen
of Squilla. Squilla itself dates
back to the Upper Jura (Litho-
graphic Slates), and species are
known from the Cretaceous of
Lebanon, Eocene of Monte Bolca,
and Highgate, England.

Sculda, Miinst. (Beckur,
Miinst. ; Buria, Giebel), (Fig.
1383). Cephalothorax orna-
mented with longitudinal mark-

FIG. 1383. ings5 an(i leaving the last three

Sculda pennata, Miinst. Upper Jura ; Bavaria. A, JS, Dorsal thoracic segments exposed. Ab-
/!. a, e, First and second ^omen broad, elongated, and with
large surfaces for the attachment
of swimming feet, the latter not preserved. The three hindermost abdominal limbs,
and the semicircular setigerous telson are developed into a caudal fin. Three species
occur in Lithographic Slates of Bavaria.

Order 4. DECAPODA. Latreille.1

Cephalothorax completely covered by the carapace, or with but one segment free; five
pairs of walking feet, the first two or three pairs usually chelate. Test prolonged into

(Palaeontogr., XV.), 1868. — Kunth, A., Ueber wenig bekannte Crustaceen von Solenhofen (Zeitschr.
deutsch. geol. Ges., XXII.), 1870. — Woodward, H., Contributions to the Knowledge of Fossil
Crustacea (Quar. Journ. Geol. Soc., XXXV.), 1879.

1 Literattire :

Miinster, G. Graf zu, Ueber die fossilen langschwanzigen Krebse in den Kalkschiefern von Bayern
(Beitr. z. Petrefaktenkunde, Heft. II.), 1839. — Meyer, H. von, Neue Gattungen fossiler Krebse, etc.,
Stuttgart, 1840. — Jurassische und triasische Crustaceen (Palaeontogr., IV. p. 44), 1854. — Die Proso-
poniden (ibid. VII.), I860.— Tertiare Decapoden aus den Alpen. etc. (ibid. X.), 1862.— Reuss, A. E.,
Zur Kenutniss fossiler Krabben (Denkschr. Akad. Wiss. Wien., XVII.), 1857.— Ueber fossile Krebse
aus den Raibler Schichten (Beitr. z. Palaeont. Oesterreichs, I.), 1858.— Bell, T., Monograph of the
Fossil Malacostracous Crustacea of Great Britain (Palaeont. Soc., 1857-62). — Italian, A., Description
des Crustacea fossiles (B-ill. Soc. Geol. France [2], XVI.), 1859.— Oppd, A., Ueber Jurassische
Crustaceen (Palaeont. Mittheil. Museum Bay. Staates I.), 1862. — von der Mark, W., Fossile Fische,
Krebse und Pflanzen aus der Kreide (Palaeont., XL), 1863.— Idem, and Schliiter, C., Neue Fische
und Krebse aus der Kreide von Westphalen (ibid. XV.), 1868. — Schliiter, C., Die Macruren-
Decapoden Westphalens (Zeitschr. deutsch. geol. Ges., XIV.), 1862.— Kreide- und Tertiar-Krebse des
nordlichen Deutschlands (ibid. XXXI.), 1879.—8timpson, W., Fossil Crab from Gay Head (Journ.

MALACOSTRACA c<;i

a frontal spine (rostrum) between the con, /,.,,<„,/ /„,/,> ,«nlate eyes. Gill* borne on or near
the basal joints of maxillipeds and leg*, >*i in a branchial chamber formed by a

ilmmward expm\*inn nf the. carapace on either */</•.

No Palaeo/oie ('nisin.-.-.-in N known which di.-play- tyj.i • i « li.iractere, and

it is possible the group did not become differentiated until tin- Trias, where tin- tir-t
undoubted remains occur. Thi-ir foivninnrrs, h«iwr\vr, an- i-vidi-ntly to be sought for
amongst the collective forms already cited undi-r th«- ,sVA /:.<,/„„/„. Although a <i
into the sub-orders Mm-rnni and /;/•<"•// //C.M is not strictly natural, yet it is of certain
convenience to the palaeontologist. The go-called Anomwra, whi.-h an- v.-ry rare in
the fossil state, are distributed between these two sub-orders.

Sub-Order A. MACRURA. Latreille. (Lobsters, Shrimps, Prawns.)

Abdomen strongly developed, as long or longer than the cephalothorax, and never
inflexed beneath the latter ; it is provided with four to Jive pairs of abdominal feet, and
the swimmerets of the sixth segment form with the telson a strong caudal fin. Tl<
pair of maxillipeds are long and slender, and do not completely cover the preceding ones.

(1) The family Carididae or prawns have a usually compressed body covered 1-y a
delicate cuticula ; legs long and slender, some or all of the pairs chelate ; rostrum
usually well developed, and

large antennal scale present. ^•[^*p**< T^"^1 — "~>-^

Undoubted Caridids are rep re- « i^r-j^^taifc...-^^

sented in the Lithographic

Slates of Bavaria by the

following genera : — Penaeus,

Fabr. (Fig. 1384); Acantho-

cheirus, Oppel; Bylgia,

Drobna, Dusa, Aeger (Fig.

1385), Blaculla, Udora, FIG. 1384.

Hefriga, Elder, Mitnster ; and Penaeus Meyeri, Oppel. Lithographic Slates ; Solenhofen. 1/2-

Udorella, Oppel. Pseudo-

crangon, Schliiter, and Oplophorus, Milrie-Edw., occur in the Upper Cretaceous of

Westphalia. Homelys, v. Meyer, and Palaemon, Fabr., are Tertiary genera, the latter

also Recent.

(2) The Eryonidae have a thin, broad, and depressed carapace, with a nu-dian
longitudinal keel ; antennal scale small ; four anterior pairs of feet chelate ; caudal tin
large. Tetrachela, Reuss, from the Upper Trias of Raibl, is one of the oldest known
Decapods. Eryon, Desm. (Fig. 1386), ranges from the Lias to Cretaceous, exquisite
examples being found in the Lithographic Slates. Polycheles, Heller, and fVillemoesia,
Grote, are recent deep-sea forms.

(3) In the Palinuridae (Loricata} the body is stout, antennal scale small, and all

Boston Soc. Nat. Hist., VII.), 1863.— Frittmk A., Ueber die Callianassen der iWihini.M-hfii Krei.le
(Abhandl. Bohm. Ges. Wiss. [6], I.), 1868.— Carter, J., On Orithopsis Bonneyi (Geol. Mag. [1],
IX.), 1872.— Decapod Crustaceans of the Oxford Clay (Quar. Journ. Geol. Soc., XLIL), 1886.—
(Ibid. LIV.), 1898.— Woodvxtrd, //., Macrurous Crustacea, etc. (il>i,l. XXIX., XXXII.), 1872-76.—
Tribolet, M., Descriptions des Crustaces du terrain ueocoinien (Bull. Soc. Geol. France I
III.), 1874-75.— BMner, A., Brachyureu des vicentischen Tertiargebirges (Deuksdir. Aka.
Wien., XXXIV., XLVL), 1877-83.— WinUer, T. C.t Etudes sur les genres Pemphix, (Jlyphaea, et
Araeosternus (Archiv. Musee Tyler [2], I.), 1883. — Ort,n<i,ui. .1. A'., Das System der Decap'-.K-n-
Krebse (Zool. Jahrb. Syst. Abth., IX.), 1896.— On Liuuparus in tlie Upper Cretaceous of Dakota
(Amer. Journ. Sci. [4], IV.), 1897. — Moericke, IP., Die Crustaceen der Straiuterger Schichteu
(Palaeontogr. Suppl., II.), 1897. — Ltircnt/iey, K., Ueber die Brachyuren der pal. Sainmlung des
Bayerischeii Staates (Tenneszetrajki Fiizetek Budapest, XXI.), 1898.— Beitrag zur Decapodenfouna
des iingarischen Tertiars (ibid.; also in Math.-naturw. lier. aus rn-rarn XIV.), 1898.

662 ARTHROPODA , SUB-KINGDOM vn

the feet non-chelate. Carapace very thick and rigid, its frontal portion always united

FIG. 1385.
Aeger tipularius, Scliloth. sp. Lithographic Slates ; Eichstadt, Bavaria. 2/3.

with the segment of the antennulae. The oldest representatives, Scapheus and

FIG. 1386.
Eryon propinquus, Schloth. sp. Lithographic Slates ; Solenhofen, Bavaria. i/2.

Praeatya, Woodward, are Liassic, Mecochirus, Kef. (Fig. 1387), is found in the Middle

SUPER-ORDER V M A |..\< '( )S'| | ; .\ ( '.\ <;<}?,

and Upper Jura. Palinurina and Cancrinus, Miinster, occur in the Lithograph i.

Fio. 1387.
Mecochirus longiinanus, Schloth. sp. Lithographic Slates ; Eichstadt, Bavaria. 1/2-

Slates. Palinurus, Miinst., and Linuparus, Gray,
range from the Upper Cretaceous to Recent.

(4) The family Scyllaridae (with the genera
Podocrates, Becks, and Eurycarpus, Schluter, from
the Upper Cretaceous; Scyllarus, Fabr., ranging
from the latter to Recent ; and the Eocene genera
Archaeocarabus, M'Coy, and ScyllaridiUj Bell) differs
from the Palinuridae in having a depressed carapace
and lamellate antennae.

(5) The Glypheidae contain but one recent genus,
Araeosternus, de Man, from Sumatra, but have a large
series of fossil forms. The family resembles the
Palinuridae in structure of appendages, but in all

Pemphix Sueurii, Desm.
Wiirtemberg. i/j.

Fio. 1388.

Muschelkalk ; Crailshein

Fio. 1389.

<;li/],hata tenuit, Opp. Lithographic SUtea;
KiiOist;i«lt, Bavaria. A, Side-view, 1/1- ^t Rostral
iv-ion .•iilaix''"!. .», n", First and second pain of
aiit.-iinae; o, Eye; «, Antennal scale; it, Base of
second pair of antennae.

664

ARTHROPODA

SUB-KINGDOM VII

other respects approaches the Astacidae. Carapace solid and roughened, cervical suture
deep ; sternum narrow ; legs monodactyle, the first pair being the largest, and in some

cases sub-ch elate. Pemphix, v. Meyer (Fig. 1388),

v occurs in the Muschelkalk ; Lithogaster and

Glyphaea, v. Meyer (Fig. 1389), range from the
Trias to Cretaceous ; Pseudoglyphaea, Oppel, is
Jurassic ; and Meyeria, M'Coy, Neocomian.

(6) The Astacidae are distinguished by the
possession of a narrow sternum ; ch elate
appendages, of which the first pair is very
strongly developed, and an antenna! scale. Both
salt- and fresh -water forms occur. Eryma, v.
Meyer (Fig. 1390), Pseudastacus, Stenochirus,
Etallonia, Oppel, are found in the Lithographic
Slates. Isolated chelae of Magila (Fig. 1391) are
abundant throughout the Jura. Enoplocytia,
M'Coy ; Nymphaeops, Schliit. ; Hoploparia,
M'Coy ; Oncoparia, Bosquet ; and Palaeastacus,
Bell, occur in the Upper Cretaceous of West-
phalia, Bohemia, and England. Homarus, Milne-
Edw. ; Nephrops, Leach ; and Astacus, Fabr.,
range from the Upper Cretaceous to Recent.

(7) The Thalassinidae
JJL have the abdomen much

elongated, carapace with
j||j two longitudinal sutures,

anterior feet the largest
FIG. 1391. and chelate, and whole

body except the chelae
enclosed in a thin integu-
ment. Numerous chelae
referable to Callianassa,

Leach (Figs. 1392, 1393), are found in the Cretaceous and Tertiary. Thalassina, Latr.,
is Tertiary and Recent.

(8) The Galatheidae differ from the last family in having the broad abdomen
slightly recurved below ; cephalothorax strongly calcified and with numerous transverse

Eryma
graphic Slates ;
(after Oppel).

FIG. 1390.

•na, Germ. sp.
Solenhofen, Bavaria.

Litho-

Vi

Magila
Quenst. sp.
Soflingen,
Chela.

FIG. 1392.

Callianassa, Archiaci, M.-Bdw. Turuniai
dragon. Var. (after Milne-Edwards).

FIG. 1393.

Mont- Callianassa antiqua, Otto. Turonian ; Turnau,
Bohemia. Right chela.

furrows ; posterior pair of feet very small and delicate. Fossils are extremely rare,
and consist only of chelae of Galathea from the Upper Cretaceous of Faxoe. Equally
rare are the chelae of Pagurus, belonging to the Paguridae or Hermit Crabs, described
from the Eocene of Hungary.

SI I'KR-OKDER V

MA I. \roSTl: AC A

Sub-Order B. BRACHYURA. Latreille. (Crabu.)

Abdomen short and reduced, wit ]t<>nf <-«ii<l,il ////, ,!,«/ ,-nri-rd around againtt the exca-
vated ventral surface of the cephalothorax ; in the male narrow and p«
two pairs of abdominal feet ; in the female broad, with four pair*

broader than long, usually depressed ; antennae »h»rt ; tl,;, ///-.//« com-

pletely covering the mouth purl*.

(1) The Dromiacea (Notopodn) have the carapac*- Mili-t nanxular, m]
or sub-orbicular, and the fifth pair of feet, which are sometim.-.-
chelate, are carried dorsally. Proaoptm, \. .M«-vr l-'j^ 1394),

FlG. 1394.

A, I'rosopon marginatum, v. Meyer. Upper Jura (<=) ; Oerlinger Valley,
near Ulm. %. jj( p. personatum. Upper Jura (y) ; Weissingen, Wiirtem-
berg. Rostrum enlarged. C, P. aciileatum, v. Meyer. Same locality as A
and D. D, P. pustulatum, Quenst.

. 1395.

Dromiopsisrugota, Schloth.
sp. Uppermost Cretiiceoun ;
Faxot-, Denmark.

appears in the Lower Oolite, is abundant in the Upper Jura, and persists into tin-
Neocomian. Similar, but somewhat larger forms with broader carapace occur in the

1300.

A, B, Ranina Marestiana, Konig( = .K. Helli, Schafli.). Eocene; Kressenberg, Bavaria. Ventral and dorsal
views. C, Chela of R. Bouilleanu, M.-Edw. Eocene ; Biarritz, France. l/->.

Upper Cretaceous. Such are Dromiopsis, Reuss (Fig. 1395); Itinkhontiu , NI wiling:
and Polycnedium, Reuss.

(2) The Raninoidea have the carapace somewhat elongate, broadest and truncat.- in
front, chelae strongly compressed, and the other feet flattened and natatory. Kaniella
and Raninoides, Milne-Edw., occur in the Upper Cretaceous. /,'»///<'/"/. I.nn. (Fig.
1396), ranges from Eocene to Recent.

(3) The Oxystomata have a rounded cephalothorax with the frontal region not
projecting. The external maxilliprds together have a triangular outline, their apices

666

ARTHROPODA

SUB-KINGDOM VII

being just behind the excurrent gill opening. Palaeocorystes, 'Bell (Fig. 1397), ranges
from the Gault to Eocene. Eucorystes and Necrocarcinus, Bell (Fig. 1398), are Cre-
taceous ; Hepatiscus,
Bittner, is Eocene ;
Calappa and Ma-
tuta, Fabr., range
from Eocene to
Recent.

(4) In the
Oxyrhyncha, or tri-
angular crabs, the

FIG. 1398.

FIG. 1397.

Palaeocorystes Stokesi,
Mant. sp. Upper
Greensand; Cam-
bridge, England.

w

FIG. 1399.

Necrocarcinus tricarinatus,
Bell. Greensand ; Cam-
bridge, England (after Bell).

Micromaia tuberculata,
Bittner. Eocene ; San
Giovanni Illariene, Italy
(after Bittner).

cephalothorax is
broad behind,
pointed in front,
and the external
Fossil forms few and small.

maxillipeds (buccal frame) are quadrilateral in outline.

Micromaia, Bittner (Fig. 1399), and

Microthorax, Noetling, are Eocene and

Miocene respectively. Lambrus, Leach,

is Eocene and Recent.

(5) The Cyclometopa (Cancroidea)

have a broad carapace, arcuate in front

and narrowed behind, without prominent

rostrum. The tribe is subdivided into

the swimming crabs (Portunidae) and

shore crabs (Cancridae), the former being

distinguished by their lamellate feet, the

fifth pair terminating in a broad flattened

paddle. To the first group belong Nep-

tunus and Achelous, de Haan ; Charybdis,

Dana ; Portunites, Bell ; Psammocarcinus,

M.-Edw. (Fig. 1400), etc., which make

their appearance in the Eocene. The

Cancridae are older ; Palaeocarpilius, M.-
Edw., appearing in the Upper Cretaceous and Eocene; and Panopaeus, M.-Edw.,

ranging from Cretaceous to
Recent. Harpactocarcinus,
M. - Edw. ; Lobocarcinus,
Reuss (Fig. 1401) ; Xan-
thopsis, M'Coy (Figs. 1402,
1403), are very abundant
in the Eocene ; Atergatis,
de Haan, in the Oligocene ;
Xantho and Cancer, Leach,
in the Neocene. Neptocar-
cinus and Carcinocarcinus,
Lorenthey, are described'
from the Eocene of Hungary
and Bavaria respectively.
(6) The Catometopa have

FIG. 1400.

Psammocarcinus Hericarti, Desm. sp. Middle Meeres-
sand (Miocene); Le Gue-a-Tresnies, France (after A.
Milne-Edwards).

Lobocarcinus Paulinc-Wiirtcmbergicus, v. Meyer.
near Cairo, Egypt. Male.

FIG. 1401.

Eocene ; Mokkatam,

the carapace quadrilateral
in outline, the front being abruptly truncated or slightly arcuate, and the sides nearly
straight and converging behind. Living species are marine, fluviatile, or terrestrial.
Galenopsis, Coeloma, M.-Edw. (Fig. 1404); Litoricola, Woodw. ; and Palaeograpsus,

v HALAC08TRAGA <-'•-

, are known from the E<x-« -m- and Oligocene. The recent Thelphuta,

Fio. 1024.
Xanthopsis Kressenbergensis, v. Meyer. Eocene ; Kressenberg, Bavaria. Male, ventral ami dorsal aspect*, Vfr

Latr., and Gecarcinus, Leach, occur in the fresh-water Miocene beds of Oeningen

FIG. 1403.

Xantho2)sis Bruckmanni, v. Meyer. Eocene; Sonthofen,
Bavaria. Ventral view of female, Vj.

i 104.

Coeloma mqll, M . K- 1 w. Eocene ; I^verda,
[taly.

and Engelwies in Baden. Archaeoplax, Stimpson, is found in tin-
Head, Massachusetts.

of Gay

Order 5. EDRIOPHTHALMA. Leach.
(Arthrostraca, Burmeister ; Tetradecapoda, Dana.)

Malacostraca with lateral sessile eyes, usually with seven, more n /' fewer free

cephalothoracic segments, and an equal 'number of pairs of legs adapted for creeping or
swimming.

Sessile-eyed Crustacea are somewhat rare in the fossil state, and as a rule are
imperfectly preserved ; this, taken in connection with the fact that the clarification is
largely based upon the minute mouth-parts, makes the identification and systematic
arrangement very difficult and often impossible.

668

ARTHROPODA

SUB-KINGDOM VII

Sub-Order A. AMPHIPODA. Latreille.

Body laterally compressed, with gills borne on the bases of the walking feet ; abdomen
elongate, the three anterior feet natatory, the rest posteriorly directed and saltatory.

The Amphipods, or beach fleas, are mostly small, aquatic animals, and generally
marine. They live in shallow water between rocks, beneath seaweed, etc., or in some
cases in tubes or burrows constructed by themselves. They leave
tracks upon the surface of mud and sand which resemble the
Palaeozoic Nereites. Fossil remains are extremely scarce, and are
derived chiefly from fresh-water strata.

A few Palaeozoic forms have been described under the names
of Necrogammarus Salweyi, "Woodw., from
the Ludlow beds ; Diplostylus Dawsoni,
Salter, from the Carboniferous of Nova
Scotia; Palaeorchestia, Zitt. (Fig. 1405),
from tlie Coal Measures'; and Bostrichopus,
Goldf., from the Culm Measures of Herborn.

FIG. 1405.

ures ; Lisek, near Beraun,
Fri?sch).ia' r

FIG. 1406.

These are all problematical forms of doubtful Gammams Oenir

-,,.,. T , . . .. ... Heer. Miocene; Oenin-

relationships. Less uncertain in its position geU) Baden, a/j.

is Acanthotelson, Meek and W., from the Carboniferous of Illinois,

which, although raised by Packard to ordinal rank (Syncarida, see above under

Schizopoda], shows no features incompatible with Amphipod

relations. The few Tertiary forms, such as Gammarus, Fabr.

(Fig. 1406) ; Typhis, Risso ; and Palaeogammarus, Zadd., closely

resemble living types.

Sub-Order B. ISOPODA. Latreille.1

Body depressed, usually broad, flat below, rounded above:
with seven free thoracic segments, and no strongly developed
carapace. Gills borne on the lamellar appendages of the abdomen,

which is short-ringed and 'often reduced, its

segments partially fused. Caudal segment

relatively large, shield-shaped.

Most Isopods are marine, frequenting

the coast ; a few inhabit fresh water, and

about an- equal number (Oniscidae) live in

moist terrestrial localities. Of the some-
what rare fossil remains, Praearcturus,

Woodward, is a large form from the Old

Red Sandstone of Herefordshire ; Amphi-

peltis paradoxus, Salter, occurs in the

Devonian of Nova Scotia ; Arthropleura,

Jordan, is found in the Coal Measures ;

Urda, Minister (Fig. 1407), in the Litho- (after Woodward).

graphic Slates ; Archaeoniscus, M. - Edw.

(Fig. 1408), in the English Purbeck ;
1 Literature :

Milne-Edwards, H., Sur deux crustaces fossiles (Ann. Sci. Nat. Zool. [2], XX.), 1843.— On
Archaeoniscus (Ann. Mag. Nat. Hist. [2], XIII.), 1844.— Meyer, H. v., Ueber Palaeoniscus obtusus
( Palaeontogr. , V.), 1858.— Kunth, A., Crustaceen von Solenhofen (Zeitschr. deutsch. geol. Ges.,
XXII.), 1870. — Woodward, H., Several papers on British Fossil Isopods in Trans. Woolhope Field
Club, 1870 ; Geol. Mag., VII., 1870 ; [3], VII., 1890 ; [4], V., 1898 ; and Quar. Journ. Geol. Soc.,
XXXV., 1879.— Ammon, L. v., Beitrag zur Kenutniss der fossileu Asseln (Sitzungsber. Bayer. Akad.
Wiss.), 1882.— Carter, J., On Fossil Isopods (Geol. Mag. [3], VI.), 1889.

Pic. 1407.

Urda rostruta, Mlinst.
Lithographic Slates ;
Solenhofen, Bavaria.
l/l (after Knnth).

FIG. 1408.
A, Archaeoniscus Brodei,

B, Frag-
ment of matrix, Vi (after
Quenstedt).

CLASS D ACERATA .;<;:»

Oyclosphaeroma, Woodw., in the Great Oolih- and l'url,<-rk ; I',,!,,,,,,,, \\'.«A\\: (Fig.

1409), in the brackisli water marls

(Oligocene) of Paris and tin- Isle of

Wight. Eosphaerwnn , Wmnlw. (Fig.

1410), and several Oniscids are found

in the Miocene of Oeningen, Baden,

and in amber.

[The different orders of Malacostraca,
with the exception of the Phyllocarids,
have been revised by Professor J. S.
Kingsley, of Tufts College, Massachusetts.
He has also drawn up the diagnoses of
the larger groups of Arthropods, and tin-
entire MS. for this phylum has received
the benefit of his expert criticism.—
TBANS.]

Class 2. AOERATA.
Kingsley.

Primitively branchiate Arthropods
in which the branchial folds function as
gills or as lungs, or become metamor- FIG. 1409.

phosed into air-tubes (tracheae) penetrat-
ing the body. The body is divided into
two regions, cephalothorax and abdomen,

Fin. 1410.

A, Eosphaeroma Brongninrti,
M.-Edw. Middle Oligocene;
Butte de Chaumont, m
3/j (after Woodward). IS, Frag-
ment of matrix, !/i (after
Quenstedt).

Palaega scrobiculata, v.
Aminon. Lower Oligo-
cene ; Haring, Tyrol, an,
Antennae ; o, Eyes ; yfi,
Hindennost swimming-
t/ie Line between the two passing behind foot; I — VI I, Thoracic

the sixth pair of appendages. Cephalo- 3^e\^' At"i'""i'

thoracic segments usually coalesced, those

of the abdomen either free or fused. Frequently a post-anal spine is present. Antennae

lacking; genital openings upon the first abdominal somite; midgut lnn<i : -<j» nnatozoa

motile ; development without nauplius or zoea stages.

The sole living representative of this group, Limulus, has long been regarded as occupying
a peculiarly isolated position among Crustacea. Its Arachnidian aflinitirs were long ago
pointed out by Straus-Durckheim, and additional reasons for removing the Merostomes from
association with the Crustacea have been brought forward by later writers, among whom may be
mentioned H. and A. Milne-Edwards, Dohrn, Lankester, van Beneden, Kingsley, and Laurie.

The points most relied upon for the association of Merostomata and Aru<-l,,ii<l<i are: (1)
the numerical honiologies of the segments and appendages ; (2) the exact homologies existing
in the respiratory organs ; (3) the fact that the cephalothoracic appendages aiv pedifbm. tin-
basal joints serving as jaws ; (4) the presence of true nephridia opening in the base <>f tin-
third or fifth pair of appendages, or in both ; (5) genital openings in the seventh (or more
probably eighth) segment of the body ; (6) extreme length of the midgut ; (7) presence of an
internal structure, the cntostcrnite ; (8) inclusion of the ventral nerve cord and it< nrm-> in
the sternal artery and its branches ; (9) the close similarities in the central nervous system
(Kingsley).

The Acerata are divided into two groups — Merostomata and Arachnuln.

Sub-Class 1. MEROSTOMATA. (Dana.) Woodward.1

Six pairs of ambulatory limbs about the mouth, the first of which in some, if i»,t in nil,
cases terminate in chelicerae. The rest serve as organs of locomotion, <n«l ///»/.•

1 The best bibliographies of Merostomata, including also historical reviews of the group, are to
be found in the following memoirs : — Woodioard, If., A Monograph of the British F<>s>il Crustacea of
the Order Merostomata (Palaeont. Soc. pp. 21-30), 1866-78. — I'urkuril, A. S., On the Carboniferous
Xiphosurous Fauna of North America (Mem. Nat. Acad. Sci. III. j.p. 153-156), 1885.

670 ARTHROPODA

SUB-KINGDOM VII

joints for prehension and mastication. Behind the mouth is a single or paired metastoma.
Cephalothorax depressed, with usually a pair each of median ocelli and lateral compound
eyes. Respiration by means of lamellate branchiae (" gill-books ") borne on appendages two
to six of the abdomen, and protected by the enlarged first pair (operculum) which covers
them. In Limulus there are no salivary glands, no MalpigTiian tubules, and no embryonic
membranes (" amnion ") are found in development.

The prevailing modern opinion is that the body is divided into two regions only
(cephalothorax and abdomen) instead of into three (head-shield, " thorax," and
abdomen), as a number of earlier writers have maintained. According to the latter
interpretation, the abdomen of Limulus is represented merely by the telson, but in
Eurypterids by a variable number of segments.

Order 1. XIPHOSURA. Gronovius.1

Body, in mature types, distinctly trilobed longitudinally. Cephalothorax large, semi-
circular, the compound eyes laterally situated, and ocelli in the centre in front. First pair
of appendages chelicerate. Metastoma with two small accessory plates. Abdomen with seven
to ten segments, which are dorsally free or coalesced; the six
anterior ones provided with lamellar appendages on the under
side. Telson long, ensiform, movable.

Family 1. Cyclidae. Packard.

Cephalothorax small, orbicular, discoidal or convex, cal-
careous or chitinous, bounded by a distinct border. Appendages
nearly as in embryonic Limulus.

FlG 1411 Cyclus, de Kon. (Fig. 1411). Known almost solely by

Cydus americanus, Pack. tne cephalothorax with its imperfectly preserved appendages,

Coal Measures ; Mazon Creek, which seem to be simple swimming legs. Their enlarged

Illinois. Showing traces of . . , .

legs and alimentary canal. Vi- J°ints cover the ventral surface of the carapace everywhere

except in the centre, which is occupied by a V-shaped plate,

towards the pointed extremity of which all the basal joints of the limbs converge.
Coal Measures ; Great Britain and Illinois.

Some of the described species are apparently larval Eurypterus, Stylonurus,
Prestwichia, etc.

1 Literature:

Hoeven, J. van der, Recherclies sur 1'histoire naturelle et 1'anatomie des Limules. Leyden,
1838. — Milnster, G. Graf zu, Beitrage zur Petrefaktenkunde, Hefte I., III., 1840. — Gegenbaur, C.,
Anatomische Untersuchungen eines Limulus (Abhandl. naturf. Ges. Halle, IV.), 1858. — Baily, W. H.,
Explanation of Sheet 137 of the Maps of the Geol. Surv. Scotland, 1859. — Remarks on Belinurus
(Ann. Mag. Nat. Hist. [3], XI.), 1863.— Giebel, C. G., Limulus Decheni (Zeitschr. gesammt. Naturw.
XXL), 1863.— Meek, F. B., and Worthen, A. H., Report Geol. Surv. Illinois, vol. III. p. 547,
1868. — Woodivard, H., On Neolimulus (Geol. Mag., V.), 1868.— On the Genus Cyclus (ibid. VII. p.
554 ; also [4], I. p. 530), 1870-94.— Notes on Merostomata (ibid. IX.), ISTZ.—Dohrn, A., Embryo-
logie und Morphologic des Limulus (Jenaische Zeitschr., VI.), 1871. — Packard, A. S., Development
of Limulus (Mem. Boston Soc. Nat. Hist., I.), 1872. — Anatomy, Histology, and Embryology of
Limulus (Anuiv. Mem. Boston Soc. Nat. Hist.), 1880. — Carboniferous Xiphosurous Fauna of North
America (Mem. Nat. Acad. Sci., III.), 1885. — Milne- Edwards, A., Recherches sur 1'anatomie des
Limulus (Ann. Sci. Natur, Zool. [5], XVII.), 1873.— Lankester, E. R., Limulus an Arachnid (Quar.
Journ. Microsc. Soc., XXI.), 1881. — Peach, B. JV., Further Researches among Crustacea and Arach-
nida (Trans. Roy. Soc., Edinburgh, XXX.), 1882. — Williams, H. S., New Limuloid Crustacean from
the Devonian (Amer. Journ. Sci. [3], XXX.), 1885.— Hall, J., and Clarke, J. M., Palaeontology of
New York, VII. p. 153, 1888.— Kishenouye, K., Development of Limulus (Journ. Coll. Sci. Tokyo,
V.), 1891.— Kingsley, J. S., Embryology of Limulus (Journ. Morphol., VII., VIII.), 1892-93.

SfH-CLASS i

MKIUJSTO.MATA

671

Family 2. Belinuridae. Packard.

Body limuloid in general aspect. Cephalothonu: fit I, l,,it(j, slender genal apine* ;
appendages as in larval Limulus. Abdomen with the segments
distinct ; telson long or short.

Belinurus, Konig. (Fig. 1412). Cephalothorax
shaped; its central portion sub-quadrate and surrounded by a
broad, flat, marginal area. Abdomen with eight aegnn-nis,
besides the very long, slender caudal spine ; segments seven
and eight are consolidated. Coal Measures ; Europe and
Illinois.

Prestwichia, Woodw. (Euproops, M. and W.). Differs from
Belinurus in having seven abdominal segments besides a short
caudal spine. Coal Measures ; Europe and Illinois.

Protolimulus, Pack. Cephalothorax large, with small
appendages ; its genal angles less produced than in preceding
genera. Abdomen with six segments besides a large, thick tounty,, Ireland
caudal spine. Upper Devonian ; Pennsylvania.

Woodwind).

>/i (after

B, The Prestwichia
stage of larval Limulus
(after Dohrn).

C, Limulus priteus,
Mmist. Muschelkalk;
Laineck near Bay-
reuth. Vi-

Fi'.. 111.-:.

A,Liimdus Wcdchi, Desm. Lithographic Slates: Solenhofen, Bavaria. Dorsal aud ventral aspects, the
latter with legs partially preserved. Original in Munich Museum. 1/2-

672

ARTHROPODA

SUB-KINGDOM VII

Family 3. Limulidae. Zittel. (King or Horseshoe Crabs.)

Body longer than broad; cephalothorax arched dorsally, the central portion separated
from the sides by longitudinal grooves ; marginal area large and flat. Abdomen composed
of six consolidated segments forming a simple sub-triangular shield, and a long slender
telson. Six pairs of abdominal limbs, five of them having over a hundred pairs of gill-

Limulus, Miiller (Fig. 1413). Living species belonging to this, the only genus of
the family, occur on the eastern shores of America and Asia. The four cephalothoracic
feet are chelate, the sixth pair furnished with a whorl of plates used in pushing the
animal through the mud. Gills are borne upon the five posterior pairs of abdominal
appendages, the anterior pair being without gills, but having the genital opening upon
the posterior face. A small species of Limulus occurs in the Buntersandstein of the
Vosges. L. Walchi is abundant in the Lithographic Slates of Bavaria ; L. Decheni is
found in the Oligocene brown coal of Teuchern, near Merseburg.

Order 2. SYNXIPHOSURA. Packard.

Body elongated ; cephalothorax semicircular with the median portion more or less
distinctly defined. Compound eyes present in some forms, ocelli not observed except in
Neolimulus. Abdomen distinctly trilobed, its segments free, the
pleurae fiat and extended, and (except in Bunodes) terminating in
lateral projections or

A las ns'satoni wiutf
ria

3/j.

With the exception of the Cambrian Aglaspis, all the genera be-
longing to this order are of Silurian age, and are too imperfectly
known as yet to permit a satisfactory grouping into families, although
several such have been proposed by Packard. Zittel united them,
together with certain genera of Xiphosura, in the family Hernia spidae,
and this term is retained with the exclusion of the Xiphosurous forms
and Aglaspis. The latter is without facial sutures.

Family 1. Aglaspidae. Clarke.

Cephalothorax moderately large, trilobed; abdominal segments
Upper Cambrian; Lodi, with distinct axis and pleurae ; telson long, spiniform.

Wisconsin. 3/j.

Aglaspis, Hall (Fig. 1414). Cephalothorax with central
portion short and conate, in front of which are approximate com-
pound eyes ; bounded on all sides by a distinct border. Abdominal
segments not grooved on the pleurae. Cambrian ; Wisconsin.

Family 2. Hemiaspidae. Zittel.

A somewhat heterogeneous group, separated by at least a
family difference from the Aglaspidae.

Neolimulus, Woodw. Cephalothorax short and broad, crescentic,
elevated mesially, and bearing ocelli. Compound eyes lateral, and
connected with the genal angles by a snture. Abdomen very
broad, composed of at least nine trilobed segments ; telson not
observed. This genus connects the Xiphosura with the Synxi-
phosura. Silurian ; Scotland.

Bunodes, Eichw. (Exapinurus, Nieszk.), (Fig. 1415). Cephalo- ten; Robtzikuii, pesei.

v T . ' Tin f -, -,. Posterior segments re-

thorax semicircular, convex, with radial furrows from the median stored from another
portion. Eyes wanting, and no genal spines. Facial sutures gj^midt)611 (af1
obscure, converging from the posterior to the anterior margin.
Abdomen divided into an anterior portion (" thorax ") consisting of six trilobite-like

FIG. 1415.

l;<i amirs lunula, var.
SdirenJd, Xieszk. Silur-

SUB-CLASS I

MKKnsToMATA

segments having a broad axis an«l laim-llar plt-iira.- with <liagonal pleural line-
posterior portion (" alxlomen ") of l<>ur nan nu, besides
a long and acuminate telson. Silurian ; OeseL

Hemiaspis, Woodw. (/.///»»//»/./.•.>•, SalU-r), (Fig. 1416).
General form similar to B anodes. Cephalothorax one-half as
long as broad, with several grnal spines; r.-ntral portion wt-11
defined. Abdomen triangular, with nine segments besides a
short telson. Abdominal axis broad, with a median ridge;
pleurae short and flat Silurian ; England.

Bunodella, Matthew. Cephalothorax .-mall, alNluminal
segments seven, acute. Axial portion of tin- l»idy |irtmiinrnt :
telson not observed. Silurian ; New Brunswick.

Pseudoniscus, Nieszk. Body oval ; cephalothorax short,
with broad central portion and large compound eyes; nim-
trilobed abdominal segments besides a short caudal spine ; th«-
posterior ones nearly parallel with the telson. Silurian :
Oesel.

Order 3. EUBYPTERIDA. Burmeister.

(Grigantostraca, Haeckel.) l
Body elongated, with a thin chitinous epidermal skeleton

i in-;.

ll< i/i iaspis limuloidrt,
Woodw. Silurian; l..-int-
wardine, England. Vi (aft»-r
Woodward).

ornamented by fine scale-like markings. Cephalothorax usually

with two large faceted lateral eyes and a pair of median ocelli; on the ventral »/<•'

six pairs of legs, of which the first is preoral and chelate. Mouth bordered posteriorly by

a metastoma, and anteriorly by an epistoma, both simple plates. Abdomen thirteen-

jointed, the anterior six segments bearing ventrally five pairs of broad, leaf-like apj>nn/nii>.<

(apparently comparable to the operculum and branchial appendages of Liiindu.*). The

posterior six segments annular, without appendages ; telson sometimes spatula.!'- in ahape.

This order, which is restricted wholly to the Palaeozoic, embraces the largest Arthropods
known, some of them (Pterygotus, Stylonurus) having attained a length of over 2 nu-tiv>.
The presence of gills upon the branchial appendages shows that in all probability tin-
Eurypterids were aquatic, and the structure of their appendages indicates that tli-
good swimmers. They are found associated with Graptolites, Cephalopods, and Trilobites in

1 Literature :

Dekay, J. ti., On a Fossil Crustacean (Ann. N.Y. Lyceum Nat. Hist., I.), 1825.— /,' / .

Ueber em Eurypterus (Palaeoutogr., I.), 1848.— M'Coy, F., Classification of some BritVi
Crustacea (Ann. Mag. Nat. Hist. [2], IV.), 1849.— Huxley, T. H., On Himantopterus (Quar. Journ.
Geol. Soc., XXL), 1856.— Idem, and Salter, J. W., On the Genus Pterygotus (Mem. Geol. Surv.
United Kingdom Mouogr., L), 1859.— Page, !>., Advanced Text-Book of Geology, 1856 and 1859.—
Nieszkowski, J., De Euryptero remipedo. Dorpat, 1858. (Also in Arch. Naturgesch. Liv.-Esth.-
und Kurlauds, II.), 1859.— Hall, J., Palaeontology of New York, III., 1859.— Stilts; J. U ..
Papers in Quar. Journ. Geol. Soc., XIX., 1863.— ir/W»'v/v/, //., Numerous Papers in (U-ol. M
1864 ; IX., 1872 ; Quar. Journ. Geol. Soc., XXL, XXIV., XXVII.. XX \ MI.. ,
Monograph of the British Fossil Crustacea of the Order Mi-m-tumata (Palaeont. Soc.), 1866-78. —
Grote, A. R., and Pitt, W. H., New Species of Eusarcus and 1'terygotus (Bull. Buffalo Soc. Nat
ScL, III.), l875.—Pohlm«/<, J., Fossils of the Water-Lime Group (ibid. IV.. V.), 1882-97.
B. Jv., Further Researches among Crustacea and Arachnida (Trans. Roy. Soc., Edinburgh, \.\.\. .
1882.— Schmidt, F., Miscellanea Silurica, III. (M.-m. A.-ad. Imp. BcL, St. IV-tt-rsb. [7J, XX XI. .
1883.— Hall, J., Second Geol. Surv. iVnusylvania, K« p. 1'IT. 1884.— Whit™
Fossils of Canada, III., Pt. 1, 1884.— Hall, J., and Clarbe,J. M.. l';d:i.-Mnt..lo_'y ..f N.-w York, VII..
1888,—Claypole, E. W., On Carcinosoma, etc. (Amer. Geol., VI., XIII.), 1890-94.— /V,///«i«/, ./..
Eurypterides uouveaux du Devonien (Ann. Soc. Geol. Belg., XVII.), 1890. — Laurie, M., Eurypterid
Remains from Pentland Hills (Trans. Roy. Soc., Edinburgh, XXXVII.), 1892.— Anatomy and Rela-
tions of Eurypterida (ibid.), XXXVIII.), 1893.— Recent Additions to Knowledge of Kurypu-rida
(Nat. Sci., III.), 1893.— Whit/i.-/,/, 11. J'., Report Geol. Survey of Ohio, VII., 1893. //
Neue Bearbeitung des Eurypterns P'ischeri (Bull. Acad. Imp. Sci.. St. IV-tersb. [o], IV.), 1896.

VOL. I 2 X

674

ARTHROPODA

SUB-KINGDOM VII

the Ordovician of Bohemia and North America ; with marine Crustacea (Phyllocarids and
Ostracods) in the Silurian ; with Ostracoderms and Arthrodites in the Devonian ; and with
land plants, scorpions, insects, fishes, and fresh-water amphibians in the productive Coal
Measures. It is apparent, therefore, that from being originally marine forms, they became
gradually adapted to brackish, and possibly even fresh-water conditions. It has been
suggested that certain clusters of small roe-shaped bodies may be the ova of Pterygotus,

On the under side of the cephalothorax there are five pairs of postoral appendages. These
legs consist typically of a basal joint, the inner margin of which is armed with teeth and
serves as a jaw, much as in Limulus or Apus. At the posterior end of the tooth-bearing
margin is attached a small oval epicoxite exactly similar to that found in the same place in
Limulus, and at the anterior angle is attached the long, usually six-jointed ambulatory
appendage. The last pair of legs is charactised in all members of the order except Stylonurus,

by its greater size and usually some-
what flattened form, and ends in an

. i oval plate. This is commonly termed

the swimming foot or " paddle," but

Laurie has suggested that the animal

TV ^^-^^^JSiilKJJBKSgF^^— -*&• used it for anchoring or burying

itself in the mud.

The ventral surface of the first
two abdominal segments is covered
by the genital operculum, which con-
sists of a pair of plates meeting in
the middle line and having a median
lobe attached to them ; the latter
varies in form in the same species,
correlating with sex. Underlying
the operculum are a number of leaf-
Hke structures, which are almost
certainly branchial in function and
represent the reduced appendages ol

7 \ IHt^*1^ tkV* jj the second free segment. The re-

maining abdominal appendages are plate -like and bear
branchiae on their posterior surfaces, being in a general
9 \TOlf 1 / way comPara^e t° those of Limulus (Laurie).

i A I:Bi s ffff IK /

Family 1. Eurypteridae. Burmeister.

This family, in the present condition of our
knowledge, is allowed to embrace all the members of
the order, with characters as given above. Future
investigation will undoubtedly show reason for the
establishment of other families,
and some authors have already
been disposed to separate Ptery-
gotus into a distinct group.

Eurypterus, Dekay (Lepido-
derma, Reuss; (?) Campylocephalus,
Eichw.), (Figs. 1417-1421). Body

Flo< 1417> elongate, narrow, attaining some-

Eurypterrus Fischeri, Eichw. Silurian ; Rootzikull, Island of times a length of 50 cm. Cephalo-
Oesel. Restoration alter Schmidt. 1/5 natural size. A, Dorsal thorax contained five or six times
aspect, showing legs II.— VI. beneath the cephalothorax, and . . „ ,, , •,

1—13 abdominal segments. B, Basipodites of the first pair of legs in total length OI tne body,
(7); the antennae (a) between them now known to be chelicerate. rior.TOO<WI r-nnvpY snb-nuadrate
C, First lamellar appendage (operculum) of the ventral side, i/j. Depressed convex, E lie,

a, Median process composed of four joints (a1 — 4); ft, Lateral with rounded anterior angles,
portions ; c, Triangular piece at the base of the first moiety of the . . ,,.— „ noarlv «traio-lit

median process (after F. Schmidt). Anterior margin nearly straignt,

posterior slightly concave. Eyes

reniform, somewhat in front of the middle ; between them and close to the axial line
are two ocelli. The entire cephalothorax bordered by a narrow marginal furrow,
and the margin broadly enfolded on the ventral side. In the middle of the lower side

BUB-GLASS I

MATA

is tin! cleft-shape* 1 nmutli, whi.-h is honored laterally l-y th«- basal segment*
fifth pair of legs, and poetei -im-Iy l>y the large oval metastoma.

The first pair of appendages were regarded by Woodward and Schmidt a* lililon
tactile. Laurie and Holm, however, h;ivr found rviden. ••• tint : a.-, and thus

more nearly in accord with homologous strin'tun-s in other nicinl'ers of tin- f.uuilv. The tlm-.-
succeeding appendages are six- or seven -join ted, mnl eovend with In
of legs is eight-jointed, and longer than those in front of it. The posterior pair Ua p
swimming organ ; its great sul>-
quadrate basal joints enclose the
metastoma, and together with this,
cover nearly one-half of the ventral
side of the cephalothorax.

The six anterior abdominal seg-
ments together occupy about one-
fourth of the body -length. They
are short and broad, and nearly
uniform in shape ; but the second
segment has lost its hard skeleton
on the ventral surface, and the first
covers the greater part of the genital
operculum. This first segment joins the posterior
margin of the cephalothorax and consists of two lateral

FIG. 1418.

Eurypterus Fischeri, Eichw. Silurian; Rootzikiill, Island of
Oesel. Ventral aspect. II. — VI., Appendages with the joints
numbered. I'. — V'., Lamellar appendages of tV« umli-r ndfl "f
abdomen, divided by median suture. I'., First of these, or
"operculum," composed of two portions (b, I'). For abdominal
segments after 7 see next figure. Vi (after F. Schmidt).

Fio. 1419.

Fischeri, Eichw. Silurian;
bland of OaseL F-maln individual, 1/3

(from Holm).

The first six segments are moderately overlapping

Tin- following six

on the

portions and a median process.

ventral side, and divided by a median suture or cleft into two parts.

abdominal segments are ring-like, tapering posteriorly, and the boay is terminated by a long

slender telson.

About twenty-five species of Euryptcrus are known, the largest being about 40 cm. long.
They are found for the most part in argillaceous or sandy deposits in transition strata 1»
the Silurian and Devonian of England, Gottland, Oesel, Podolia, and in tin- Watcrlinu- Group
of New York. They are rare in the Devonian, but occur again more frequently in the Coal
Measures of Scotland, Silesia, Bohemia, Saarbriickeu, and Pennsylvania. The last survivor

676

ARTHROPODA

SUB-KINGDOM VII

is from the Permian of Bussaco, Portugal, where it occurs in association with land plants
( Walchm, Sphenopteris}. Type, E. remipes, Dekay.

Echinognathus, Walcott. Imperfectly known. Cephalo thoracic appendages with
numerous curved spines, indicating an animal of large size. Ordovician ; New York.

Dolichopterus, Hall. Sixth
cephalothoracic leg has the two
moieties of the terminal joint sub-
equal in size, and developed as
two distinct joints, making nine
instead of eight elements in these
appendages. Otherwise as in
Eurypterus. Waterlime (Upper-
most Silurian) ; New York.

Eusarcus, Grote and Pitt
(Drepanopterus, Laurie ; Eurysoma,
Carcinosoma, Claypole). Eury-
pterids with the first six abdominal
segments greatly expanded, those
following being abruptly con-
tracted. Terminal joint of the
sixth cephalothoracic appendage
not expanded. General aspect of
body scorpion - like. Silurian ;
New York, Indiana, Pentland

FIG. 1420.

Hills.

Anthraconectes,

M. and W.

Eurypterus remipes, Dekay. Waterlime (Silurian) ; Buffalo,
New York. Ventral surface of young individual. The first (2nd ?)

pair of legs, relatively large size and length of swimming feet, Like Eurypterus. but without spines
and abrupt posterior contraction of abdomen are especially . . . ., ,

notable. 3/x. on the joints of the cephalothoracic

appendages, and the median process
of operculum with two accessory lateral plates. Coal Measures ; Illinois.

Adelophthalmus, Jordan and v. Meyer. Eyeless Eurypterids. Coal Measures ;
Saarbriicken.

Eurypterella, Matthew. Very small, elongated forms. Cephalothorax small,
triangular ; the first four abdominal segments together sub-quadrate
in outline. Surface "tuberculated on the posterior edge of the
segments. Devonian ; New Brunswick.

Slimonia, Page (Himantopterus, Salter), (Fig. 1422). Body
attaining a length of 60 cm., and width of 15 cm. Cephalothorax
sub-quadrate, with anterior marginal eyes and median ocelli. Preoral
appendages in the form of small stout pincers, much like chelicerae
in Limulus, but probably masticatory rather than prehensile. Of
the five pairs of postoral appendages, the first is modified to form
tactile organs, and is small and chelate ; the second also slender Buffalo, New Ymk.
and probably tactile. The first seven abdominal segments much Jj^i sh'owing^the
wider than the rest, and divisible into two parts, a dorsal (tergite) strongly anterior posi-

Qnrl Q tron + T»0 1 ( of 0WI V 1 0\ TMlQ •fivoi- -ftirr* cH-nivt^-i-f-r^ o-w,r» •«/-*-K\-*irkctn-r\ -f f\r\ Tvir „ , *. * '*- ' \

JJJJj

1/1-

and a ventral (sternite). The first two sternites are represented by
the genital plate and its posterior divisions ; the other five are
discontinuous plates bearing branchial lamellae on their inner
surface. The five posterior segments are long, narrow, and
cylindrical. Telson like that of Pterygotus, but produced into a longer spine.
one species. Old Red Sandstone ; Scotland.

Stylonurus, Page. Body similar in general proportions to Pterygotus, and often
exceeding 1 m. in length. Cephalothorax quadrate or sub-pentagonal, its margins

Only

srii-l'LARS I

MEKOSTOMATA

077

bent under so as to cover m.,iv than on. --half of th.- \. •nn.il -MI- face, Eyes large,
approximate, sometimes .surrounded by strong orbital ridgrs ; ""-Hi <>n the slope of a
median ridge. Preoral appendages kn«.\\u ««nly by fragment.. .,-. Of th,-

five pairs of postoral appendages, tin- lir-t is . -In-hit.-, tin- n.-.\t t\\o an- -li.,it, and each
joint bears a pair ..f lam. -liar processes. The last two pair- an- .•in.niu.n-ly . lougated,
nine-jointed, extruding almost to the end of the telson, and t.-rminai.- in I
Number of aMominal .-egim-nt.- believed t«. In- the same as in Knr;ii>trriu; each <•!' the
posterior .segments sometimes l>car a pair of detachable pr.H-i--.-i- ..r .-pini.-i.i. Telson

FIG. 1422.

Slimonia acuminata,
Walter. Devonian ; Lanark-
shire, Scotland. Restora-
tion of ventral siirtao-,
showing legs I. — VI. and
abdominal segments VII. —

!•'[<;. 1 I'.1:'..

Pterygotui - lunidt. Silurian; U.Mit/.ikMll, Island .•:

XIX. The first rive of the stm-atii'ii ut' v.-ntral suitacc. ,t, K])istnina ; ».. M.-tast.iina ; oc, K\---: I. \'i..
latter with branchial AppMtdaatt. with juints Dtmibend serially in the jwworful swimmr
lamellae. 1/7 (after Laurie). I'.— \"., 7', First six alxluminal segments. '/:j (:i«tT F. Schniidtjt

long and slender. Silurian and Devonian; Scotland. Upper Devonian ; New Y..rk
and Pennsylvania.

Pterygotus, Agassiz (Figs. 1423-1425). Gigantic Eurypterids, attaining a length
of over 2 m. Ceplialothorax semicnate, with anterior marginal eyes and central
ocelli. Comb-like organs are present beneath the cephalothorax as in Glyptoscorpitu.
The metastoma is a heart-shaped plate attached along the middle line to tin- v.-ntral
wall of the cephalothorax, between the liases ol' tin- last pair «i' l.-.vrs and ext»-nding
outwards and forwards so as to enclose the jaws in a kind of chamber. Epistoma a
thin semicircular plate, occupying the same position as hypostoma in Trilobites, and
having the preoral appendages attached close t » its posterior border. The latter are
large pincers, probably prehensile in function ; by Schmidt and Woodward they are
represented as many-jointed, but Laurie states them to consist of but three long joints.
Behind the mouth are four pairs of slender walking legs, followed by the large

678

ARTHROPODA

SUB-KINGDOM VII

" swimming feet," which are similar to those in Eurypterus, except that they are less

broadly expanded at the tips. Telson an oval
plate, terminating in a slight projection. The
species first referred' to this genus (P. pro-
blematicus, Ag.) is but imperfectly understood,
and P. anglicus, Ag., which is well known, is
generally accepted as the typical form of the
genus. Uppermost Silurian ; Wales, Scotland,
Oesel, New York. Old Red Sandstone ; Scotland.

Erettopterus, Huxley and Salter. As in
Pterygotus, but with a bilobed telson. Silurian ;
Lanarkshire.

Glyptoscorpius, Peach. Body attaining a
length of 30 cm. Surface covered with highly
developed scale - markings. Limbs ending in a

FIG. 1424.

Pterygotus anglims, Agassiz. Old Red Sand-
stone ; Forfarshire, Scotland. Restoration of
ventral surface, but second pair of legs not
represented. i/5 (after Woodward).

FIG. 1425.

Pterygotus Bu/aloensis, 'Grote. Waterlime (Silurian) ;
Buffalo, New York. The toothed antennal chela. 1/2-

double claw, as in scorpions, and the animal further provided with a pair of comb-like
structures closely resembling the pectines of scorpions. Coal Measures ; Scotland.

[The chapter on the Merostomata was outlined in substantially its present form by Dr.
John M. Clarke, of Albany, who furthermore contributed a number of new illustrations, both
for this section and others on the Eucrustacea which he has revised for this work. Some
additional details were introduced under the generic diagnoses by the Editor, and the whole
text finally subjected to the criticism of Dr. J. S. Kingsley and the Author. — TRANS.]

Sub-Class 2. ARACHNIDA. Spiders, Scorpions, Mites, etc.

A cerata with six pairs of limbs around the mouth, at least four of which are ambu-
latory in function. Eyes simple, variable in number. Respiration by lung-books or by
tracheae, these in either case developed from gill leaves arising on the posterior surface of
one or more abdominal appendages. Gephalothorax usually without signs of segments
dorsally. Abdomen sometimes clearly segmented, sometimes with the segments obsolete, and
apodal. Malpighian tubes, when present, ectodermal in origin.

Six of the eight orders into which living Arachnids are divided occur in the fossil
condition, and of these the scorpions, spiders, and Pedipalpi have existed ever since
the Palaeozoic. By far the greatest number of species is preserved in amber of Lower
Oligocene age from East Prussia. This fossil gum acts as a marvellous preservative,
the most delicate parts, including the finest hairs and even spiders' webs, remaining
practically unaltered.

The order Acari (Mites, Ticks) comprises forms in which the cephalothorax is
anchylosed with the unsegmented abdomen. Fossil representatives occur in amber or
fresh-water deposits of the Tertiary, and belong with few exceptions to recent genera.

SUB-CLASS II

AI;A< iixihA

The order Chelonethi (False Scorpions) is distinguish^! fY'-m tin- . l«m' by having a
segmented alidimu-ii. The recent genus Chelifer (Fig. 1426) occure fossil in ain

The order Anthracomarti, as (l«-liii«-l l.y K.u- h ,,n<i S. ii'M.-r, is restricted to tn*e
Carboniferous. The cephalothorax and al«: li.-t im-t, and tin- lattrr is com-

posed of four to nine segments. Tin- oephalothorai i'iv<|iiriitly presents wedge--
segments In-low. Examples: Arthrolycoaa, Hargcr Fiur. M-7 : /'•-/' '••••/(' /••/.';. / <///irynu*,

FIG. 1420.

Chelifer Hemprichii, Merge.
Oligocene ; Baltic amber.
Copy, 9/i.

Fio. 1427.

Arthrolycosa antiqua, Harger. Coal. Measures ;
Mazon Creek, Illinois. »/i (aft«r Beecher).

1428.

Architarbus rotund-
atus, Scudd. Coal Mea-
sures ; Mazon Creek,
111. Under surface, »/i-

Architarbus, Scudder (Fig. 1428); Anthracomartus, Karsch (Fig. 1429); Kreischeria,
Geinitz ; Eophrynus (Fig. 1430), Brachypyge, Woodw. ; Phalangiotarbus, Haase, etc.

The order Pedipalpi has the first pair of legs exceptionally long ; cephalothorax
and abdomen distinct ; and some forms with a setigerous postabdomen. Certain

Fid. 1429.

Anthracomartus Vodkdianus,
Karsch. Carbon Coal Mea-
sures ; Neurode, Silesia. Dor-
sal surface, 1/1 (after Karsch).

Fia. 1430.

Eophrynus Prestwichii, Bucklaiul
sp. Coal Measures; Coalbrookdale,
England. Dorsal surface, 1/1 (after
Woodward).

Fio. 1431.

Gtralinura Bohemica, KoiU tp.
Coal Measures; Hakonitz,
Bohemia. Vi (after Kulta).

fragments from the Devonian of New Brunswick are referred here by Matthew.
Geralinum, Scudder (Fig. 1431), is Carboniferous; Stenarthron, Haase, occurs in the
Lithographic Slates of Bavaria. Phrynus, Latr., is Tertiary and Recent

In the order Scorpiones the posterior end of the body consists of a preabdomen with
seven segments, and a long slender postabdomen of six segments, the last of which
forms a hollow poisonous sting. Scorpions are among the oldest of Arachnids.
Palaeophonus, Thorell (Fig. 1432), and Proscorpius, Whitf., are known from the
Silurian. Eoscorpius, M. and W. (Fig. 1433), Centromachus, Thorell, and Cycloph-
thalamus, Corda, are Carboniferous genera. A species of Tityti*, Koch, is found in
amber.

680

ARTHROPODA

SUB-KINGDOM VII

The order Opiliones is distinguished from true spiders by having the cephalo-
thorax and abdomen fused. A number of species occur in amber, and according to
Haase, most of the Anthracomarti should
be placed here. The Araneae (Spiders)
have numerous fossil representatives, at
least one genus, Protolycosa (Fig. 1434),
occurring as early as the Carboniferous.
The majority, however, are found in

FIG. 1432.

Palaeophonus nuncius, Thorell and Lindstrom.
Silurian ; Wisby, Gottland. Vi (after Thorell).

FIG. 1433.

Eoscorpius carbonarius, Meek and W. Coal Measures ;
Mazon Creek, Illinois. A, 1/1- B, Pecten, enlarged.

Oligocene amber (Fig. 1435); the lignites of Rott ; fresh-water marls of Aix in

FIG. 1434.

Protolycosa anthra-
cophila, Roemer.
Coal Measures ;
Myslowitz, Silesia
(after F. Roemer).

FIG. 1435.

FIG. 1436.

Mlzalia rostrata, Koch and A ttoides eresiformis, Brongt.
Berendt, Oligocene ; Baltic Oligocene ; Aix, Provence,
amber. Copy, 3/lt lo/j (after Brongniart).

Tlwmisus Oeningensis,
Heer. Miocene; Oen-
ingen, Baden. 2/j (after
Heer).

Provence (Fig. 1436) ; Oligocene fresh-water strata of Florissant, Colorado ; and the
Miocene of Oeningen, Baden (Fig. 1437).

VERTICAL UANiJK oK Till: Ai:.\< HNIDA »;M

TABLE SHOWING THE VERTICAL RANCK <>F Till: A i;.\CII \ II > \ !

Ordi

7.

j

j

i

••»

I

I

ACARI
CH ELONETH I

34
9

2

ANTHRACOMARTI .
PEDIPALPI ....
SCORPIONES ....
OPILIONES ....
ARANEAE ....

3

16
2

8

......

1
13

aii

is

SUB-PHYLUM B. MYRIOPODA.

Tracheate Arthropods with distinctly separated head and numerous fairly similar
segments, each of which bears one or two pairs of legs. Body vermicular, apterous.
Head with one pair of antennae and three pairs of jaws.

The head in Myriopods is formed by a single division, which only in exception,! 1

cases is supplemented by parts of the following body segments. The two most

important orders are Chilopoda and Diplopoda. In the former, which approaches very

closely to Insects, every body segment possesses a single dorsal and a ventral plate, to

which a pair of legs is attached. The

Diplopods, on the other hand, show on every

segment except the first a dorsal plate and

two ventral plates, with two pairs of legs.
A precursor of the Chilopods is found

in the genus Palaeocampa, M. and \V., from

the Carboniferous, whose body is composed

of but a, few segments. Scudder place.s it

in a distinct order, Protosyngnatha. True

Chilopod genera (Germatia, Kossi ; Scolopendra, Linn. ; Lithobius, Geophilm, Leach)

ocGiir in anilx-r and the fiv.<h- water gypsum ••!'
Aix, Provence.

Most Palaeozoic Myriopods are of large size
and belong to the order Archipolypoda, in which
all body segments possess two dorsal and two
ventral plates, with two pairs of legs. Two
genera are found in tin- old Red Sandstone of
Scotland, Archidesmus, Peach (Fig. 1438) ; and
Kampecaris, Page. Numerous others occur in
the Carboniferous and Trias of both continents,
and sonic have l>ccn recognised by Matthew in
the Devonian of New Brunswick. Kzamples :

Euphoberia, M. and W. (Fig. 1439); Amynilispes, Scudder; Xylobim, D<iwson ;

Acantherpestes, M. and W., a genus regarded by Scudder as probably amphibious.
From Mesozoic rocks but a single species is known (Jiilnpniit

Ki... .

Ar<-hi>i- rh. Devon:.-;

. Scotland. 1/1 (after IVarlu.

Fiii. 1439.

Euphoberfo, armigera, Meek ami W.
Measures ; Maxon Creek, Illinois. 1/1-

Coal

1 The figures indicate the number of species, as estimated in 1885.

682 ARTHKOPODA SUB-KINGDOM vn

Several Diplopods are found in the Tertiary, especially in amber. Examples : Julus,
Linn. (Fig. 1440); Craspedosoma, Leach; Euzonus, Menge;
Polyxenus, Latr. ; Phryssonotus, Scudder (Lophonotus,
Menge).

SUB-PHYLUM C. INSECTA (Hexapoda). Insects.1

Tracheate Arthropods with body at maturity consisting
of three divisions — head, thorax, and abdomen ; supplied
with a pair of antennae on the head, three pairs of legs, and
usually two pairs of wings on the thorax. The latter is

cene ; Rott, near Bonn, Germany, composed of three, and the abdomen of nine or ten segments.

Copy, 1/1. Development usually through metamorphic stages.

Fossil Insects can be referred, usually without difficulty, to the existing orders of
Aptera, Orthoptera, Neuroptera, Hemiptera, Coleoptera, Diptera, Lepidoptera, and'
Hymenoptera. 'The Palaeozoic forms, however, show a less marked differentiation in
the structure of their wings and are more closely related to each other than their
successors of the corresponding orders. Scudder, on this account, unites these primitive
precursors by placing them in a special group (Palaeodictyoptera), and compares its
representatives, under the names of Orthopteroidea, Neuropteroidea, Hemipteroidea, and
Coleopteroidea, with the typical Orthoptera, Neuroptera, etc., of later date.

The researches of C. Brongniart 2 regarding the rich Palaeozoic fauna of Commentry,
although they lead to the conclusion that strangely differentiated forms occurred in
the different groups even in the Carboniferous, show even more conclusively than
before that this differentiation had little depth, and that it is only through their
presumable descendants that we have any claim to a wide separation of the original
Palaeozoic forms. The neuration of the wings, though diversified, had yet a far
greater homogeneity than is found now, or than existed during Mesozoic time. The
fore wings of whatever type were as diaphanous as the hind, and could never (as in most
of their descendants) properly be called tegmina. The wings of the Protodonata (Fig.
1260) of Brongniart had indeed a superficial resemblance to living Odonata in shape,
reticulation, and sweep of the veins ; but in fundamental neuration they were altogether
different, and they wholly lacked any sign of those characteristic features of the
Odonata, termed the nodus, triangle, and pterostigma, which appear fully developed in
the Mesozoic species. Nor should it be forgotten how highly probable it is that the
Lepidopteran, Dipteran, and Hymenopteran phyla had their origin in types already
recognised in frhe Palaeozoic. In a text-book, however, and perhaps in any general
treatise, it may be best to bring the Orthopteroidea, Neuropteroidea, etc., in direct
connection with the Orthoptera, Neuroptera, etc., as indicative of the precise phylogeny
of the latter groups.

Order 1. APTERA.

Wingless insects with hairy or scaly body covering ; with rudimentary masticating
mouth parts and setiform anal filaments, which may serve as a springing apparatus, at
the end of the ten-segmented abdomen. Development without metamorphosis.

1 [The most complete guides to the literature of fossil Arachnids, Myriopods, and Insects are to
be found in the writings of Professor Samuel H. Scudder, of Cambridge, Mass. , who has revised the
translation of these chapters for the present work — without, however, having altered their system-
atic arrangement. One should consult especially his collection of papers in two volumes, entitled
Fossil Insects of North America (New York, 1890) ; Bulletin of the United States Geological Survey,
Nos. 31, 69, 71, 93, 101, 124 ; Vol. XIII. of the Annual Reports; and XXI. of the Survey Mono-
graphs (Washington, 1886-95) ; also his discussion of the above-named groups in ZitteVs Handbuch
der Palaeontologie, Vol. II. (Munich and Leipsic, 1885).— TRANS.]

2 See his important work : Recherches pour servir a Vhistoire des insectes fossiles des temps
primaires, 2 vols., St. Etienne, 1893.

\

SUB-PHYLUM III

INSKCTA

083

Fl... 1441.
•'* nrticorn.il, Koch and

To this lowly organised class of insects belong th.- Thytanura und < U-mbola
(Spring-tails). Brongniart describes I uj> from th<- Carbop-

iferous of Conimentry (Dasypeltus Lucari), \\hi.-li
resembles tlie living Lepisma, but has only a single
terminal filanu-nt. In amber and the. Oiigocene of
Florissant ;i numlx-i- of species are found, some of
which belong to still living, and others to extinct

genera. Examples: PetroUus (Fig. 1441), Lepidion, g" *m**-

Forbicina, Machilis, etc. Planocephalus, a headless

form from the Oligocene of Colorado, is regarded by Scudder as the type of a di.-tim-i
sub-order.

Order 2. ORTHOPTERA.

Fore wings coriaceous, hind wings thinner, delicately veined, plicated. The five
principal veins of the wings, with all their branches, extend to the outer margin <>f ih?
wing. Jaws adapted for biting. Metamorphosis incomplete.

Palaeozoic representatives of this order frequently combine characters which are at
present distributed among different families. The neuration of their wings also shows

FIG. 1442.

Palaeoblattina Douvillei,
Brongt. Silurian ; Jnrques,
Calvados. 2/3 (after Brongniart).

Fio. 1443.
Aedoeophasma Anglica, Scudder. Coal Measures ; England. 1/1-

a less marked differentiation than is the case in more recent Orthoptera ; moreover,
the fore and hind wings differ less decidedly from each other than in the later form-.

An isolated wing from the Middle Silurian of Jurques, Calvados (PalaeobUtt'tn>t
Douvillei, Brngt., Fig. 1442), is one of the oldest of fossil insect remains, but does not
admit of closer determination ; Brongniart no longer regards it as a cockroach. The
Carboniferous of North America and Europe yields numerous genera and species,

which are more or less closely related to typical
Orthoptera. Some of these are of gigantic propor-
tions. The richest localities for remains of this
order are Commentry, France ; Saarbriicken and
Halle, Germany ; Illinois ; Ohio ; and West Virginia.
Many genera are known only by detached wings.
Among the largest and best preserved forms are
Protophasma, Stenoneura, Aedoeophasma (Fig. 1443),
and Paolia. Smaller forms include Polioptentu
(Fig. 1444); Oedischia with saltatorial hind legs; Stethaneura, Caloneura, and
Ischnoneura. Cockroaches, however, were the prevailing type during the Palaeozoic,
fully 200 species being known, belonging to the genera Etoblattina, Gerablattina,
Anthracoblattina, Progonoblattina (Fig. 1445), Mylacris, etc. Spiloblattina from tin-
Trias is placed in the same group as the Palaeozoic forms, under the name of Palaeo-

Polioptenus elegans, Goldenbg. sp. Coal
Measures ; Saarbrucken, Germany. Vi-

684

AETHEOPODA

SUB-KINGDOM VII

blattariae, Scudder. According to Brongniart, the female was, in some cases at least,
provided with a long ovipositor.

The Forficutidae (Earwigs) are found in the Lias of Aargau, in
amber, and in the Tertiary of Aix, Oeningen, Monte Bolca, and
Florissant.

True Blattariae (Cockroaches proper) begin in the Trias of
Colorado and Europe, and occur quite abundantly in the Lias of
Schambelen, Aargau, and in the Upper Jura of England and
Bavaria. They have also been shown to exist in amber and in
different Tertiary localities. Examples : Scutinoblattina, Neor-
throblattina, Legnophora, Trias. Blattidium, Rithma, Mesoblattina,
Blabera, Jura.

FIG. 1445.

Progonoblattina Col-
umbiana, Scudder.
Coal Measures ; Mazou
Creek, Illinois. 2/j.

Drymadusa specie

FIG. 1440.
sp. Miocene; Oeningen, Baden. 2/j.

FIG. 1447.

Fossil remains of Mantidae and Phasmidae (Walking Sticks) occur rarely in the
Tertiary. The Acridiidae (Grasshoppers) ; Locustidae (Locusts, Fig.
1446) ; and Gryllidae (Crickets, Fig. 1447) are known from the Lias
onward, and are not uncommon in the Tertiary. A large grass-
hopper, Locusta speciosa, Munst., is found in the Lithographic
Slates of Bavaria. Pygolampis gigantea (Chresmoda obscured) is
considered by Haase as also a precursor of Mantidae and Phasmidae.

Order 3. NBUROPTBRA.

Both pairs of wings large, of nearly equal size, membranous, and

traversed by numerous delicate
Antennae

reticulated nervures.

simple. Metamorphosis complete QSSS91^SSSSll

or incomplete. Baltic amber. 3/2

(after Germar).

Like the Orthoptera, Palaeo-
zoic forms of this order are characterised by their
meagre differentiation, and are called by Scudder
Neuropteroidea. Unless Palaeoblattina (see above)
belongs here, the oldest fossil remains are found
in the Devonian of New Brunswick (Lithentomum,
Xenoneura, Homothetus). A very considerable
number of genera, in part well preserved, are
known from the Carboniferous of Commentry,
Saarbriicken, Bohemia, Saxony, Great Britain,
and Illinois. Examples : Acridites, Palingenia,
Genentomum, Propteticus (Fig. 1448), Strephocladus,
Lithomantis (Fig. 1449), Lithosialis, Brodia. Chres-
totes, Hemeristia, Megathentomum, Mischoptera,
Psilothorax, Sphecoptera, Corydaloides, Homalo-
neura, Blanchardia, Gompsoneura, Meganeura (Fig. 1260, p. 604), etc.

FIG. 1448.

Propteticuk infernus, Scudder.
ires ; Illinois. 3/o (after Scudder).

SUB-PHYLUM III

INSKCTA

880

The family Twin ft /»/</• \Vl.it.- Ant- begini in tin- l.ia>, ami i- \v,-ll ivj.iv.-.-nt.-.| n,
the Tertiary, especially in arnl.rr, tin- Oligocene of I ami Mi...,i,, .

]•'!<;. 111'.'.

Lithomuntis carbonaria, Woodward,
land. 2/3 (after Woodward ).

Coal Measures ; Scot-

si-. ( ili^ocf ne ; H:iltic amber.
»/l (after Pictet).

Oeningen, and Rodoboj. One unusually large species, Gigantotermes (Apochrysa) exceha,
Haase, appears as early as the Lithographic Slates of Bavaria,

Psocidae (Book - lice), Embidae, and Perlidae sometimes occur in amber.
Ephemeridae (May Flies), whose precursors are found in Palaeozoic rocks, are

'-"•"'-- ': -•'-/ •„'. .:':."'--

Petalia /«/,,/;,,/,//,». Mun-i. .-]'•
Lithographic ' Slates ;
B;iv;iri;i. - ;!.

Colorado.

Oligocene ; Florissant,

preserved in the Lithographic Slates, in amber (Fig. 14.">o), and in certain Tertiary
deposits.

Especial interest centres in the numerous and excvllrntly ]>i<->«'i \ c.l remains of
Odonata (Dragon Flies) from the Lithographic Slates of Bavaria, such as Petalia
(Fig. 1451), Stenophlebia, Isophlebia, Aeschna, Anax, Heterophkbia, etc. The group
begins in the Lias, but is hardly so \vrll n-iuv^-nn-d in tin- 'JVrthry a> wonl<l U-
expected. Trichocnemis (Fig. 1452). Oligocene.

686

ARTHROPODA

SUB-KINGDOM VII

Fossil remains of Sialidae, Hemerobidae (Lace-winged Flies), Panorpidae, and
Phryganidae (Caddis Flies) are first met with in the Trias and Jura, and increase
considerably in numbers during the Tertiary. Ootheca of gigantic Sialidae
(Corydalites) are known from the Laramie Beds of Colorado,
and from the Garumnien (Uppermost Cretaceous) of Provence.
The tubular larval cases of Phryganidae from the Tertiary
are sometimes 2-3 m. thick (Indusienkalk, calcaire
a induses, of Auvergne).

Order 4. HBMIPTERA. (Rhynchota.)

Fore wings coriaceous or membranous, larger
and more coarsely veined than the hind wings, which
are never folded. Mouth with jointed, beak -like,
suctorial rostrum. Metamor-
phosis incomplete.

The oldest known fossil
insect is a somewhat obscure
wing, plainly Hemipterous
(Protocimex silurica, Moberg),
from the Graptolite Slates of
the Swedish Upper Ordo-
vician. Carboniferous genera
are Fulgorina, Dictyocicada,
Mecynostoma, and Phthano-
coris. The first-named is also
found in the Permian, together
with the remarkable genus
Eugereon (Fig. 1453), which
has large, membranous,
reticulated fore and hind wings, prolonged lancet -like mouth parts, and filiform
antennae.

The oldest remains of Aphidae (Plant-lice) are found in the Wealden, and
numerous species occur in the Tertiary. Coccidae
(Scale Insects), Fulgoridae, Membracidae, Cicadellidae,
and Cicadidae (Harvest Flies) are tolerably abundant in
the Tertiary, especially in amber. Most of the families

Eugereon Boecklngl, Dohrn.
s/4 (after Dohrn).

FIG. 1453.

Permian ; Birkenfeld, Oldenburg.

FIG. 1454.

Scarabaeides deperditus, Gennar.
Lithographic Slates ; Eichstadt,
Bavaria. */s.

FIG. 1455.

Naiicoris dilatatus, Heer.
Miocene ; Oeningen. Eaden.
Vi (after Heer).

FIG. 1456.

Harpactor maculipes,
Heer. Miocene ; Oenin-
gen, Baden. */i (after
Heer).

are represented as early as the Lias, or even by scanty remains in the Trias (Cercopyllis,
from Colorado). Cercopidium occurs in the Lias of Dobbertin. Eocicada and Prolystra
in the Lithographic Slates of Bavaria.

SUB-PHYLUM III

INSKCTA

Of tlu- ;u[U,itic bugs, a number of families an- met \\itli in tin- .lur.i, -n«-li
Nepidae, Hydrometridae, Reduviidae, Lygaeidae, Cor-
Thripsidae, and Cimicidae. Scarabaeides (Fig. 1454) occurs
in the Bavarian Litln^rajilii.- Slate-. Kxainpltt of Tertiary
genera are: Naucoris (Fig. 1455), Harpactor (Fig. 1456),
Cephalocoris (Fig. 1457), Berytopsit, Acanthosoma, and Eothes.

Order 5. COLEOPTERA. Beetles.

Fore wings (elytra) chitinous, thick, with obsolete nervures ;
hind wings membranous, folded, with nervures connected only at
wide intervals. Prothorax freely movable. Mouth parts mastica-
tnn, Metamorphosis complete.

Coleopterous remains have not been recognised with
certainty in the Palaeozoic. Dipeltis is of doubtful position,
but bears a certain resemblance to the larvae of beetles. During the Mesozoic and
Tertiary, however, this group occupies a prominent
position among insects.

Remains of Curculionidae, Chrysomelidae, and
Buprestidae are found in the Trias of Vaduz and
Rutihard, near Basle ; and
the same families occur more

v

Flo. 1458.

Cyphon vetustus, Giebel.
Purbeck ; Vale of Wardour,
England. «/i (after
Brodie).

FIG. 1459.

Cerylon striatum, Brodie.
Purbeck ; Vale of Wardour,
England. J/i (after
Brodie).

Flo. 1460.

Fossil Beetles from the Oligocene
marls of A ix, Provence. A, Hipporhinu*
Jleeri, Oustalet. 2/j. If, Triphytliu
'ustalet. 8/1. C, Htfetinus
. 4/,.

abundantly in the Rhaetic and chief divisions of the Jura in Europe. Among the
richest Mesozoic localities may be mentioned : Schambelen in Aargau (Lias) ; Dob-
bertin, Mecklenburg (Lias) ; Stonesfield Slate and Purbeck of England (Figs. 1458,

Fi.;. 1463.

O

.

.\l>'i<i?i l ifi'i ;i"t,' III, SdlddlT.

Hiocciie Florissant, Colorado.

fruiii oli^ocene amber of East
.1. /;„;-,•„>•,„•,/.< i,;i..i,,,.<, \!
Ji, Ptilodaetyloidtt .*ti].iilicomitt
»/,. C, Pavttoides Mengci,

Fio.

Paltorhyndit

Scudder. Oligocene; Flo-
rissant, Colorado. «/i.

1459). The Bavarian Lithographic Slates yield comparatively few, and fur the most
part poorly preserved remains of beetles (Pseudohydrophilua, Chrysobothris).

A marked increase took place during the Tertiary, and by far the greater
number of species are referred to still living genera. The Oligocene fresh -w.it IT
deposits of Aix in Provence (Fig. 1460), and of Florissant, Colorado (Figs. 1461, 1462),
are especially rich in species; also the amber of East Prussia (Fig. 1463), Miocene

688

ARTHROPODA

SUB-KINGDOM VII

lignites of Rott, Sieblos, Wester wald, Kutschlin in Bohemia, the fresh- water marls of
Oeningen, Baden (Fig. 1464), and certain localities in Croatia, Italy, Utah, and

[FiG. 1464.

Beetles from the Miocene fresh-water marls of Oeningen, Baden. A, Lytta Aesculapii, Heer. 1/2- B, Clerus
Adonis, Heer. Vi- C, Same restored. D, Hister marmoratus, Heer. 2^. E, Nitidula maculigera,~H.eer. 2/j.

Wyoming. Of the rhynchophorous families alone about 350 Tertiary species have
been described, most of which are excellently preserved. Perhaps the most curious
form is Triaena, a parasitic Stylopid from amber.

Order 6. DIPTBRA. Flies.

Fore wings membranous, narrow, veined,
(halter es). Mouth parts adapted for piercing

Hind wings reduced to clubbed filaments
nd sucking. Metamorphosis complete.

Fossil flies are first encountered in the Lias (Macropeza), but most of the Jurassic
forms are too poorly preserved for accurate identification. Musca, Cheilosia, and

Empidia are known from the Litho-
graphic Slates ; Corethrium, Cecido-
mium, and Rhyphus from the English
Purbeck.

The Tertiary, especially Oligocene
and Miocene, yields large numbers of

Heer \^u ^ies' Tipulidae (Crane Flies) and

Miocene ; Radoboj,'Croatia. *$&, Bibionidae being the most abundant.

m other families represented are:

Syrphidae, Muscidae, Oestridae (Bot
Flies), Agromyzidae, Platypezidae,

FIG. 1465.
Psilites bella,

FIG. 1466".

' Kmjns Meliu, Heyden.
Miocene ; Root, near Bonn,
Germany, -/i (after
Heyden).

2'alembolus florigerus,
Scudder. Oligocene ; Floris-
sant, Colorado. 2/x (after
Scudder).

FIG. 1468.

Chironomus Meyeri, Heer. Miocene ; Oeningen,
Baden. 6/j (after Heer).

Psilidae (Fig. 1465), Empidae (Fig. 1466), Bombylidae, Nemestrinidae (Fig. 1467),
Asilidae (Robber Flies), Stratiomyidae, Chironomidae (Fig. 1468), Gulicidae (Gnats)
Mycetophilidae (Fig. 1476), Cecidomyidae, etc.

SUB-PHYLUM III

INSECTA

Order 7. LEPIDOPTBRA. Butterflies and Moths.

Fore and hi ml iri,i<j.< timi'lnr, scaled, usually brilliantly coloured. Mouth parts
suctorial, forming a spiral proboscis. Metamorphosis complete.

Lepidoptera are very rare in the fossil state, and known as yet only from t la-
Tertiary. Pseudosirex (Sphinx) Schroeteri, from the Lithographic Slates of Bavaria, was
considered a LepidopU-ron by Oppehheim, l>ut by Deichmuller as a wood-wa>p
(Uroceridae).

Most of the larger groups have isolated representatives in the Tertiary. The
smaller moths (Microlepidoptera) occur in amber in various stages of development.
Two species of Phalaenidae are known from Radoboj ; a third is found at Aix, and
another (Lithopsyche) in the Isle of Wight. Species of Noctuidae and several

FIG. 1469.

Prodrya,s Persephone, Scudder. Oligocene ; Floris-
sant, Colorado. Vi-

FIG. 1470.

Barbarothea Florissanti, Scudder.
Oligocene ; Florissant, Colorado. Vi-
(after Scudder).

Bombycidae have been described from Aix and from Oeningen. Of the Hawk-moths
(Sphingidae) Sphinx is found in amber, and Sesia at Aix. Butterflies are very rare,
but about a dozen genera are known from the fresh -water strata of Aix. Rott,
Radoboj, and Florissant. From the last-named locality Prodryas (Fig. 1469) is
exquisitely preserved. Two of the eight species known from this rich locality
(Prolibythea, Barbaro-
thea, Fig. 1470) belong
to the now nearly extinct
but widespread group of
Libytheinae.

Order 8.

HYMBNOPTERA.

Fore wings larger
than the hind pair, thin,
membranous, with few
and separated nervures.
Mouth parts adapted for
biting and licking. Pro-
thorax fused. Metamor- Slates; Eichstadt, °B:ivuria.
phosis complete.

The oldest Hymenoptera occur in the Lias of Schambelen in Aargau, and belong

to the ants. Apiaria, Belostomum (Fig. 1471), and Pseudosirex have been described

from the Lithographic. Slates ; Formicium and Myrmicium from the Purbeck. All

other remains are of Tertiary age, and belong to the Tenthredinidae (Fiir. 1 17^ .

VOL. I 2 Y

A tocus defessus, Scudder. Oligocene; Floris-
sant, Colorado. 3/i.

690

ARTHEOPODA

SUB-KINGDOM

M VII

Uroceridae (Wood Wasps), Gynipidae (Gall Flies), Ichneumonidae (Fig. 1473),
Braconidae, Chrysididae (Gold Wasps), Vespidae (Wasps), Apidae (Bees, Fig. 1474)|
Formicidae (Ants, Fig. 1475), etc. They are most abundant in amber, and in the

FIG. 1473.
Ichneumonites bellus, Heer. Mio-

cene ; Oeningen, Baden.
Heer).

5/2 (after

FIG. 1474.

Xylocopa senilis, Heer. Mio-
cene ; Oeningen, Baden, 1/1 (after
Heer).

FIG. 1475.

Prionomyrmex longiceps,
Mayr. Oligocene ; Baltic
amber. 2/x (after Mayr).

fresh- water strata of Aix, Oeningen, and especially Radoboj and Florissant. A species
of Myrmar, one of the minutest insects known, belonging to the parasitic Proctro-
trupidae, has been found in Baltic amber.

Range and Distribution of the Insecta.

According to Scudder, about 2600 fossil insects had been described up to 1885,
of which 155 were Palaeozoic species, 475 Mesozoic, and 1972 Tertiary. Since then
these figures have been considerably increased by discoveries at Cornmentry, Florissant,
in amber and elsewhere.

The oldest fossil insect is Protocimex from the Swedish Ordovician. Following
this are PalaeoUattina from the Middle Silurian of Calvados, France, and several
Devonian forms from New Brunswick.

A marked increase in numbers and variety of form is observed in the Coal
Measures, the most noted localities being Commentry in Department Allier, and
Mazon Creek, Illinois. Other localities for the older fossil insects are Zweibriicken,
Wettin-Lobejiin near Halle, Manebach in Thuringia, the Belgian and British coal-
fields in Europe, and Nova Scotia, Pennsylvania, Ohio, and Rhode Island in America.

The Permian (especially the Rothliegendes of Weissig in Saxony, Stockheim in
Bavaria, Lebach near Saarbriicken, and Cassville, West Virginia) yields few, but in
part very interesting species, for example, those of Eugereon. From different localities
of the Trias, Heer describes several Orthoptera, and also two beetles from Vaduz in
Liechtenstein. To these must be added about twenty species recently discovered in
the South Park of Colorado, nearly all of which are cockroaches. The Lias of
Schambelen in Aargau, Dobbertin in Mecklenburg, and Gloucestershire, England,
contains a tolerably rich insect fauna. Only a few species are derived from the
Stonesfield Slates, but the Purbeck of Southern England, on the other hand, is quite
rich. Excellently preserved remains are found in Lithographic Slates (Upper Jura)
of Bavaria, especially at Solenhofen, Eichstatt, and Kelheim. The Cretaceous again is
very poor in insect remains, most of the forms occurring in Bohemia.

Some Eocene species are known, but for the most part not yet fully described,
from the Isle of Wight and phosphorites of Quercy, France. The Oligocene insect
fauna is surprisingly rich and varied. By far the greatest number of species is
derived from Baltic amber ; other interesting localities are Aix in Provence,
Florissant, and the White River region of Colorado. The Miocene localities of

SUB-PHYLUM III

INSKCTA

Oeningen in Baden, liadol.nj, Parsdilug, Rott on tin- Khinr, etc., an- scarrdy lene rich
than the Oligocene.

In tlie Pleistocene, the intergladal day- of S\vit/«-rlaii'l ami «•!' ( )]itari<., < 'ana«la,
tin- peats of Northern l-'rancr and England, and the ligniU-s of II..-l.;n-li( Il.ivaria,
deserve mention as localities for fossil insects.

TABLE SHOWING THE VERTICAL RANGE OF FOSSIL INSECTS.

i

1

Orders.

1

1

1

i

1

«l

ca

i

--

B

»-s

I

1

AFTER A

OUTHOPTEKA

__

NEUROPTERA

?

,

"^^^

^^^~—

^__

—^—

HEMIPTERA

_

——.

^— ^~

^^_

COLEOPTEUA

DlPTERA

LEPIDOPTERA

HYMENOPTERA

FIG. 147C..
Necromyza pedata, Scudder. Miocene ; Oeningen, Baden. 12/j (after Scudder\ See under Diptera, p. 688.

INDEX

[Names of genera and sub-genera regarded as synonyms are printed in italics, all others in Roman.]

Abacocrinus, 144

Actinosepia, 603

Ambites, 563

Anatomites, 554

Ahatita, 245

Actinostoma, 281

Amblycoceras, 578

Anatropites, 554

AUacomya, 371

Actinostreon, 373

Amblypneustes, 232

An ax, 6»5

Abra, 418

Actinostroma, 112

Amblypygus, 239

Anuzyya, 333

Acambona, 338

Acus,'481

Amblysiphoiiella, 65

Anchura, 470

Acanthactinella, 55

Adacna, 413

Ambocoelia, 336

Ancilla, 481

Acantherpestes, 681

Adelactaeon, 485

Ambonychia, 368

Ancillaria, 481

Acanthinites, 560

Adelastraea, 90

Amicula, 435

Ancistroceras, 521

Acanthocaris, 655

Adelophthalmns, 676

Amita, 367

Ancistrocrania, 311

Acanthoceras, 585

Adeorbis, 452

Ammodiscus, 23

Anculosa, 4(57

Acanthocheirus, 661

Adranaria, 363

Amnicola, 464

Ancyloceras, 588

Acanthochites, 435

Adrianites, 562

Amnigenia, 374

Ancylus, 494

Acanthocladia. 283

Aeclnnina, 644

Amoeboceras, 580

Ancyropyge, 633

Acanthoclymenia, 548

Aedoeophasma, 683

Amphiastraea, 87

Androgynoceras, 578

Acanthocrinus, 145 ! Aeger, 661

Ampliibola, 493

Anyaria, 449

Acanthocyathus, 84 Aeglina, 630

Amphiceras, 574

Angelinoceras, 521

Acanthodictya, 55

Aegoceras, 557

Amphiclina, 340

Anisactinella, 340

Acanthonautilus, 525

Aeolopneustes, 233

Amphiclinodonta, 340

Anisocardia, 394

Acanthopleura, 436

Aerope, 248

Amphicoelia, 368

Anisoceras, 587

Acanthopleuroceras, 578

Aeschna, 685

Amphidesma, 418

Anisocrinus, 164

Acanthopora, 267

Aesiocrinus, 160

Amphidonta, 373

Anisomyon, 492

Acanthosoma, 687

Aeteleocystites, 186

Amphidoxa, 498

Anisophyllum, 76

Acanthotelson, 668

Aetomoceras, 575

Am phi gen ia, 322

Anisothyris, 422

Acanthoteuthis, 599

Aetostreon, 373

Amphion, 635

Anisotrypa, 277

Acanthothyris, 325
Acasta, 652

Agaricia, 91
Agaricocrinus, 143

Amphiope, 237
Amphipeltis, 668

Anodonta, 378
Anodontopsis, 393

Acaste, 636

Agassiceras, 575

Amphipora, 113

Anolotichea, 268

Acavus, 495

Agassizia, 246

Amphispongia, 55

Anomactinella, 339

Acentrotremites, 196

Agassizocrinus, 162

Amphistegina, 32

Anonialanthus, 237

Acervularia, 79

Agathelia, 84

Amphistrophia, 313

Anomalocaris, 641

Aceste, 248

Agathiceras, 562

Amphithelion, 54

Anomaloceras. 524

Acestra, 55

Agelacrinus, 187

Amphitomella, 339 Anomalocrinu's, 152

Achatina, 496

Agina, 422

Arnphoracrinus, 141 Anomalocystites. 186

Achelous, 666

Aglaspis, 672

Amplexopora, 278

Anomalodonta, 368

Acidaspis, 633

Agnesia, 443

Amplexus, 76

Anomia, 384

Acila, 363

Agnostus, 624

Ampullina, 462 Anomphalus, 451

Acleistoceras, 530

Agoniatites, 549

Ampyx, 625 Anopaea, 370

Aclisina, 457

Agraulus, 628

Amusium, 381 Anoplia, 316

Acmaea, 442

Agria, 404

Amynilispes, 681

Anoploceras, 525

Acridites, 684

Agulhasia, 329

Anabacia, 93

Anoplophora. 375

Acrioceras, 588

Aipoceras, 525

Anabia, 338 Anoplotheca,'338

Acritis, 306

Akera, 486

Anadara, 366 Anoptychia, 456

Acrochordocrinus, 169

Alaria, 470

Anadenus, 498 Anorthopygus, 239

Acrocidaris, 228

Alecto, 174, 260

AnagymnitM, 557 Anotoceras, 553

Acroculia, 461

Alectryonia, 373 Anahamulina. 571 Alitalia. 431

Acrosalenia, 227 Alexiaj 493 Anahedenstro'emia. 555

An ted on, 174

Acrothele, 308 Alipcs, 471

Anahoplites, 584

Anthocrinus, 150

Acrotreta, 308 Allagecrinus, 135

Analcites, 560

Anthonyia, 397

Acrura, 204 Allocrinus, 148

Analytoceras, 568

Anthracoblattina, 683

Actaeon, 484 Allodesma, 393

Anamalina, 30

Anthracochiton, 434

Actaeonella, 485 Allopagus, 392, 411

Ananchytes, 243

Anthracomartus, 679

Actaeon ina, 485

Alloprosalocrinus, 143

Anapell'a, 421

Anthracomya, 374

Actinacis, 95

Allori.sina, 388

Anarcestes, 549

Anthraconectes, 676

Actinocamax, 597

Allotrychia, 368

Anarthropora, 288

Anthracopteni, 372

Actinoceramus, 370 Alocolytoceras, 572

Anascaphites, 572

Anthracosia, 374

Actinoceras, 528 Alsatites, 575

Anasibirites, 558

Antinomia, 329

Actinoconchus, 339 Alveolina, 26
Actinocrinus, 141 j Alveolites, 100

Anasirenites, 560
Anaspides, 659

Antipleura, 362
Antiptychina, 332

Actinodesma, 367

Amalia, 497

Anastrophia, 321

Antirhynchonella, 321

Actinodonta, 378

Amaltheus, 577

Anatibetites, 560

Anuscula, 363

Actinometra, 175

Amaura, 462

Anatimya, 389

Aparchites, 644

Actinomya, 391

Amauropsis, 462

Anatina, 389

Apasmophvllum. 76

Actinopteria, 370

Amberleya, 449

Anatinella, 420 ; Aphanaia, 372

694

TEXT -BOOK OF PALAEONTOLOGY

Apheleceras, 523

Aspidoceras, 582 ' Bactropus, 656 Bisidiuonea, 262

Aphetoceras, 519

Aspidophyllum, 78

Bactrotheca, 491 Bittium, 469

Aphragmites, 516 Aspidopora, 273

Bactrynium, 316

Bittnerula, 335

Aphyllites, 549 Aspidosoma, 207

Baculina, 584

Blalmra, 684

Aplysias, 487 Aspidura, 204

Baculites, 571

Blaculla, Hi;]

Apioceras, 530

Assilina, 33

Badiotites, 556 Blanchardia, 684

Apiocystites, 187 Assiminea, 464

Baerocrinus, 152 Blattidium, 684

Apleuroceras, 556 Astacus, 664

Bairdia, 646

Blauneria, 493

Apioceras, 527 Astarte, 395

Bakewellia, 369

Boletia, 233

Aplococeras, 556 Astartella, 394

Balariocrinus, 174

Bolivina, 28

Aplodon, 378 Asteractinella, 56

Balanocystites, 186

Bollia, 644

Aplustruni, 486 . Asteroblastus, 188

Balanophyllia, 93

Bolma, 448

Apochrysa, 685 Asteroceras, 575

Balantium, 489

Bontaea, 390

Aporrhais, 470 ; Asterodaspis, 238

Balanus, 651

Borelis, 26

Apricardia, 400 ; Asthenodonta, 374

Balatonites, 559

Borsonia, 483

Apsendesia, 264 Asthenosoma, 226

Baltoceras, 517 Boskovicia, 463

Apsorroceras, 584 Asthenothaerus, 390

Bambaganites, 561 Bosnites, 560

Aptychopsis, 658
Aptyxiella, 467

Astieria, 583
Astraeomorpha, 94

Barbarothea, 689 Bosquetia, 646
Barbatia, 366 Bostrichopus, 668

Aptyxis, 467

Astraeopora, 95

Baroda, 416 Bostrychoceras, 5?8

Apus, 641

Astraeospongia, 56

Barraiideites, 554 Bothriocidaris, 219

Arachnocrinus, 156

Astraliunt, 448

Barrandella, 322 Bothrocorbula, 422

Arachnocystites, 184

Astrangia, 86

Barrandeoceras, 519 Botriopygus, 240

Arachnoides, 238

Astrocladia, 49

Barrandeocrinus, 144 Botryllopora, 270

Araeacis, 85

Astrocoenia, 90

Barrettia, 406 Botryocrinus, 157

Araeosternus, 663

Astroconia, 55

Barroisella, 307 Botsfordia, 306

Arbacia, 231

Astrocrinus, 198

Barroisia, 65

Bouchardia, 333

Arbusculites, 317 ! Astrohelia, 84

Barroisiceras, 588

Bourgetia, 450

Area, 366 Astroides, 93

Bartlettia, 378

Brachiospongia, 55

Arcestes, 565

Astropecten, 208

Barycrinus, 157

Brachtrema, 458

Archaediscus, 32

Astropyga, 230

Baryphyllia, 88

Brachymerus, 326

Archaeocarabns, 663

Astrorhiza, 23

Baryphyllum, 74

Brachyprion, 313

Archaeocaris, 659

Astylocrinus, 162

Barysmilia, 90

Brachypyge, 679

Archaeocidaris, 220

Astylomanon, 50

Basterotia, 392

Brachythyris, 335

Archaeocrinus, 145

Astylospongia, 50

Buthmoceras, 517

Brachytrema, 459

Archaeolepas, 650

Asymptoceras, 525

Bathybius, 18

Branchipodites, 641

Archa.eoiiiscusj (508

Atactodea, 421

Bathycyathus, 84

Brancoceras, 552, 590

Archaeoplax, 667

Atactopora, 278

Bathynotus, 627

Brasilia, 576

Archaeoscyphia, 48

Atactoporella, 272

Batillus, 448

Brechites, 391

Archaeosphaerina, 35

Ataxioceras, 581

Batissa; 397

Breynia, 247

Archaeozonites, 497

Atelecrinus, 175

Batocrinus, 142

Brilonella, 443

Archasterias, 207

Atelestocrinus, 158

Batostoma, 275

Brissomorpha, 247

Archidesmus, 681

Atergatis, 666

Batostomella, 277

Brissopatagus, 247

Archimedes, 282

Athlete, 480

Battersbvia, 79

Brissopsis, 247

Architarbus, 679

Athyris, 338

Bayania, 456

Brissus, 247

Arcicardium, 413

Atlanta, 455

Bayanoteuthis, 598

Brocchia, 460

Arcomya, 389

Atoma, 483

Baylea, 443

Brodia, 684

Arcomyopsis, 361

Atomodesma, 372

Bayleia, 401

Brodieia, 576

Arcopagia, 417

Atops, 627

Beachia, 326

Broeckia, 362

Arctica, 395

Atractites, 595

Becksia, 61

Bronteus, 632

Arctoceras, 559

Atretia, 325

Beecheria, 328

Brvograptus, 114

Arenicola, 256

Atrina, 369

Bela, 482

Bryopa, 391

Arethusina, 631

Atrypa, 334

Belemnitella, 597

Bucania, 445

Argas, 657

Atrypina, 334

Belemnites, 596

Buccinopsis, 476

Arges, 632

Aturia, 522

Belemnopsis, 597

Buccinulus. 484

Argina, 366

Atvs, 487

Belemnosis, 598 Buccinum, 475

Argiope, 330

Aucella, 372

Belemnoteutliis, 599

Buchiceras, 590

Argonauta, 603

Aulacoceras, 595

Belgrandia, 4fi4

Buchiola, 362

Argopatagus, 248

Aulacophylum, 76

Belinurus, 071 Buchites, 560

Arietes, 575

Aulacorhynchus, 318

Bellardia, 469 Buddliaites, 557

Arieticeras, 570

Aulacostephanns, 583

Bellerophon, 445

Bulimina, 28

Arioliamax, 498

Aulacotliyris, 332

Beloceras, 554

Buliminus, 496

Arion, 498

Aulocopium, 47

Beloptera, 598

Bulimulus, 495

Ariophanta, 497

Aulonotreta, 306

Belopterina, 598

Bulla, 487

Aristella, 385

Aulophyllum, 78

Belosepia, 601

Bulluea, 487

Aristocystites, 182 Anlopora, 101

Beloteuthis, 602

Bullina, 485

Aristozbe. 656 Aulosteges, 317

Beneckia, 554

Bullinella, 487

Arnioceltites, 557 ; Auricula, 493

Berenicea, 261

Bullinula, 485

Arnioceras, .".7") Aurigerus, 582

Berytopsis, 687

Bundenbachia, 203

Arniotites, 558 Aurinia, 480

Beyrichia, 644

Bunodella, 673

Arpadites, 560

Austriella, 324

Bevricliites. 556

Bunodes, 672

Arrhoges, 471

Autodetus, 463 Bdellacoma, 207

Buria, 660

Artemis, 415

Avellana, 486 Bicavea, 264

Bursacrimis, 160

Arthrocantha, 140

Avicula, 370 Bicrisina, 262

Bushia, 390

Arthroclema, 281

Aviculopecten, 380 Bidiastopora, 261

Buskia, 264

Arthrolycosa, 679

Aviculopirma, 369

Bifida, 338

Buskopora, 270

Arthropleura, 668

Axinea, 366

Bifrontia, 458

Busycon, 477

Arthropora, 279 Axinopsis, 410

Bigenerina, 28

Bylgia, 601

'Arthrostylus, 280 Axinus, 410 Billingsella, 312

Byssocardium, 413

Asaphis, 418 Axosmilia, 89 Billingsia, 306

Byssomya, 422

Asaphus, 629 Azara, 4-J2

Billingsites, 516

Byssonychia, 368

Ascoceras, 516 1 Azeca, 496

Bilobites, 319

Bvssopteria, 368

Aspergillvm, 391

Biloculina, 26

By thine! la, 464

Aspidiscus, 88 Babinka, 367

Binkhorstia, 665

Bythinia, 464

Aspidites, 556 Bactrites, 549

Biradiolites, 403

Bythocypris, 646

Aspidocaris, 658 Bactropora, 281

Birostrites, 405

Bythopora, 277

1NDKX

Bythotrypa, 268

( 'arriiiucairiii'

riniis, 1(J1

riadnpora, 100

Caroiti <vjj.>i>ur:i, 260

ClaiM-ul

Caberea, 284 ,244 Ceritella, 409

Cacabocrinus, 148 < anlilia, l-Jl Oerithidea. 470
Cactocrinus, 141 CardinJ (v.itl.inella, 469

Clat!in»li,-t\..ii, !!•_'

Clathropora,

Cadoceras, 580

raidiiiorrania. :;n CerlthiopcU, 4i;:»

Clatlini.

Cadomella, 313

Canlinca: < ''-ril hiim, .

ClauM

Cadomia, 303

Cardioceras, 580

Cermatla, 681

Clausilia, 495

Oodomites, 580 rardi'.lu, W2 Cernina, 462

C]:iiisiinult.-l.-a, -J71

Cadoinoceras, 569 Cardlolitea. Ceromya, 388

Clavagella, :;c.'l

Cadulus, 43-2

Cardiomorpha, 362 .-oncha, 392

Clavatnla, 482

Caecella, 421

Cardi(jn,\ Cetomya, -J'.':;

Clavella, 478

Caecilianella, 496

Cardita,

Chaena, 423

I'l,, ,•;,•!,! HSU, 263

Caecum, 466 Carditamers, 399

Chaenocaris, 657

Clavulina, 28

Cainocrinus, 173 Canlitrlla.

riiai'iminya, 362

Cleidophorus, 363

Calamocrinus, 169

Oardium, 412

Chaenopea, 422

rii'idothfca, 491

Calamophyllia, 87

Carinaria, 455

Chaetetes, 102

Cleiothvris, :;

('«l<iin»t>ora, 99

Carinopora, 281

Chaetopleura, 435

CleiRtechi nus, 248

Calapoecin w

Carnites, 557

Chainodictyon, 283

Cleodora, 489

Calappa, 666

Carolia, 384

Chalmasia, 372

Cleonoceras, 569

Calcar, 448

Carpenteria, 31, 874

Cliaina, 399

Cliiiiacaiiiiniiia, 28

Calcarina, 31

Carpocrinus, 143

Chaperia, 403

Climacograptus, 119

Calceocrinus, 154

Carpomanon, 50

Charionella, 341

Clinoceras, 530

Calceola, 80
Callianassa, 664

Carpospongia, 50
Carterella, 52

Chartronia, 577
Charybdis, mn;

Clinolobus, r,o-_'
Clinopistha, 361

Callicrinus, 149

Carterina, 113

Chasmops, 637

Clintonella, 334

Calliderma, 208

Carychium, 4!>3

Cheiloceras, 551

Clinura, 482

Calliostouia, 451

Caryocaris, «;;,.'!

Cheilosia, 688

Cli... -is;.

Callistocliiton, 435

Caryocrinus, 185

Cheilotoma, 444

Clionychia, 368

GalliBtoplaz, 435

Caryocystites, 184

Cheiropteraster, 207

Clisiophyllum, 77

Callix.m, 656

Caryomatton, 50

Cheirurus, 635

Clisocolus, 414

Callocardia, 414

Caryophyllia, 84

Chemnltzia, 456, 457

Clisospira, 463

Callochiton, 435

Caryospongia, 50

Chenendopora, 53

Clitambonites, 320

Callocystites, 187

Casearia, 59

Chenopus, 470

Clonopora, 262

Callogohia, 414

Cassianella, 371

Chicoreus, 477

Clorinda, 322

Callograptus, 114

Cassidaria, 474

Chilina, 493

Clydonautilus, 521

Callonema, 458

Cassidula, 493

Chilocyclus, 458

Clydonites, 559

Callopegma, 48
Callopoma, 448

Cassidulina, 29
Cassidulus, 240

Chilopora, 267
Chiloporella, 268

Clymenonautilus, 521
Clypeaster, 236

Callopora, 275

Cassiope, 465

Chilotrypa, 269

Clypeus, 241

Callotrypa, 277

Cassis, 474

Chiton, 436

Clypites, 556

Caloceras, 575

Castocrinus, 154

Chitonellus, 435

Cnemidiastrum, 52

Caloneura, 683

Catazyga, 333

Chlamydoconcha, 411

Cnemidium, 52

Calostylis, 92

Catenipora, 102

Chlamys, 381

Cnisma, 365

Calpiocrinus, 164

Catillocrinus, 153

Chlorostoma, 451

Coccocrinus, 139

Calveria, 226

Catillus, 370

Choanoceras, 515

Coccophyllum, 89

Calycoceras, 589

Catopygns, 240

Chofatia, 581

Coccoteuthis, 602

Calymmene, 634

Catosira, 457

Chonaxis, 77

Cochlearia, 458

Calymne, 244

Catulloceras, 576

Chonechiton, 434

Cochloceras, 561

Calyptogena, 399

Caunopora, 113

Choneplax, 435

Cochlodesma, 390

Calyptograptus, 114

Cavea, 263

Chonetella, 317

Cochlolepas, 461

Calyptraea, 461

Cavolinia, 489

Chonetes, 316

Codakia, 408

Camarella, 321

Cea, 270

Chonopectus, 317

Codaster, 197

Camarium, 341

Cecidomiuni, 688

Chonophyllnm, 78

Codecliinus, 230

Camarocrinus, 183

Celaeno, 603

Chonostegites, 102

Codiacrinus, 158

Camarophorella, 323

Cellaria, 285

Chonostrophia, 317

Codiopsis, 230

Cainarophoria, 322

Cellepora, 286, 290

Choriplax, 435

Codoceras, 532

Camarospira, 341

Cdlcporaria, 290

Choristites, 335

Codonaster, 197

Cainartoechia, 324

Celleporella, 288

Choristoceras, 561

Codonites, 198

Cameroceras, 514

Cellularia, 284

Choristrodon, 417

Coelastarte, 395

Camerospongia, 61

Celtites, 558

Chorizopora, 288

Coeliocrinus, 160

Camerotheca, 491 Cenoceras, 526

Chresmoda, 684

Codocaulis, 269

Cainerothyris, 332 Cenomanites, 584

Chrestotes, 684

Coelocentrus, 447

Camitia, 451 j Centroceras, 525

Christiania, 314

Coeloceras, 579

Campeloma, 463 ; Centromachus, 679

Chrysaora, 267

Coeloclema, 268

Campophylluin, 77 Centronella, 326

Chrysobothris, 687

Coeloconus, 281

Camptonectes, 381 r-iitrostephanus, 229
Campyloccphalus, 674 Cent rothcca, 491

Chrysodomus, 476
Chrysomelon, 233

Coelocorypha, 54
Coelodon, .V..'

Cainpyloceras, 527
Canalipora, 263

Cephalocoris, 687
Ceramophylla, •_' s

Chrysostoma, 452
Chthamalus, 652

Coelogasteroceras, D24
Coeloma, 666

Canavarites, 577

Ceramopora, 267

Cicatrea, 395

Coeloinactra, 420

Cancellaria, 481

Ceramoporella, 2t'i7

Cidaris, 223

Coelonautilus, .v_':i

Cancer, 666

Ceratiocaris, 654

Cimitaria, 388

Coelopleurus, 231

Cancrinus, 663

Ceratisolen, 419

Cincta, 332

Coeloptychium, 60

Cantantostoina, 444

Ceratites, 559

Cinulia, 486

Coelosmilia, s-.t

Cantharidus, 451

Ceratolichas, 632

Cionella, 496

Coelospira, 338

Cantharus, 475

Ceratx)psis, 644

Circe, 416

Coelostylina, 456

Capellinia, 322

Ceratosiphon, 471

Circopora, 113

Coenites, 100

Caprina, 401

Ceratostreon, 373

Cirrus, 450

Coenocyathus, 84

' Caprinella, 403

Cewtothecu, 491

Cirsotrema, 458

Coenograptus, 118

Caprinula, 403

Ceratotrochus, 83

Cistella, 330

Coenothvris, 333

Caprotina, 403

Ceratozona, 435

Cladangia, 86

Coleoloides, 490

Capulus, 4i)0

Cercomya, 389

Cladiscites, 566

Coleolus, 490

Caratoinus, 230

Cercopidium, 686

Cladochomis. 101

Collina, 579

Carbonarca, 365

Cercopyllis, 686 Cladocora, 86

Collonia, 448

Carbonicola, 374

Ceriocava, 266

Cladocrinm, 173

Collyrites, 242

696

TEXT -BOOK OF PALAEONTOLOGY

Colobocentrotus, 232

Craspedopoma, 460

Cyclas, 398

Cystiphyllum, 79

Coloceras, 523

Craspedosoma. 682

Cyclaster, 247

Cystispongin, 61

Colospongia, 65 Craspedostoma, 449
Colpocaris, 655 Crassatella, 397

Cyclichna, 487
Cyclidia, 452

Cystocidaris, 219
Cystodictva. 280

Colpoceras, 514
Columbella, 475

Crassatellina, 397 Cyclina, 415 Cytaster 187
Crassatellites, 397 \ Cycloceltites, 558 Cvthere. 645

Columnaria, 79 Crassina, 395

Cycloceras, 518, 578 ' Cytherea, 415

Columnastraea, 90 I Crassinella, 395, 397

Cycloclymenia, 548 , Cythereis, 645

Columnopora, 99 Craterina, 182

Cycloclypeus, 34 Cytherella. 646

Coins, 478 i Craticularia, 57 Cycloconcha, 393 i Cytherellina. 646

Colymmatina, 49 Crenatula, 370 \ Cyclolites, 94

Cytheridea, 645

Co-master, 175

Crenella, 386

Cyclolituites, 521

Cytherideis, 645

Comatula, 174

Creniceras, 569 Cyclolobus, 564

Cytherodon, 363

ComatuUna, 174

Crenipecten, 380 Cyclolomops, 472

Combophyllum, 74
Cominella, 475

Crepidophyllum, 77 Cyclonassa, 476
Crepidula, 461 Cyclonema, 448

Dactylioceras, 579
Dactyloteuthis, 597

Comoseris, 94

Crepipora, 268 ' Cyclophorus, 460

Dactulus, 484

Compressidens, 431

Crescentilla, 658 . Cyclophthalamus, 679 Dadocrinus. 167

Compsoneura, 684

Creseis, 489

Cyclophyllum, 78 Dalila, 362

Conactaeon, 485

Creusia, 652

Cyclopora, 283 Dallina, 331

Conchicolites, 254

Cribrilina, 287

Cycloporella, 283 > Dalmanella, 319

Conchidium, 321

Cribrostomum, 28

Cyclorhina, 325 ! Dalmariites, 637

Conchocele, 410

Crioceras, 588

Cyclosphaeronia, 669 ; Danilia, 451

Conchodon, 376

Crioceratites, 588

Cyclostoma, 460 Danubites. 559

Concholepas, 478

Crisia, 260, 489

Cyclostomiceras, 530

Daonella, 371

Confusastraea, 90

Crisina, 262

Cyclostrema, 452

Daphnella, 483

Congeria, 386

Cristellaria, 27

Cyclotrypa, 269

Daphnites, 560

Conocardium, 369

Cromus, 634 i Cyclotus" 460

Daraelites, 563

Conocephalites, 627

Cromyocrinus, 161

Cyclus, 670

Darellia, 576

Conoceras, 517

Crossopodia, 256

Cylindra, 480

Dasyceras, 567

Conoclypeus, 234

Crossostoma, 449

Cylindrites, 485

Uasvneltns. 683

Conocoryphe, 627

Crotalocrinus, 150

Cylindrobullina, 485 • Daudebardia, 496

Conocrinus, 169

Crucibulum, 461

Cylindromitra, 480 ! Davidsonella, 306, 316

Conodonts, 255

Cruratula, 332

Cylindrophyma, 51 Davidsonia, 314

Conolampas, 242

Cryptacanthia, 328 -

Cyllene, 476 1 Daviesiella, 318

Conolichas, 632

Cryptaenia, 443

Cymaceras, 569

Davila, 421

Conorbis, 483

Cryptangia, 86

Cymaclymenia, 548

Dawsonoceras, 518

Conoteuthis, 599

Cryptaulax, 469

Cymatoceras, 526

Dayia, 334

Conotreta, 308

Cryptaxis, 95

Cymatochiton, 434

Deakia, 247

Conotuligera, 263 '

Cryptoblastus, 196

Cymbites, 575

Decacnemos, 174

Conradia, 306

Cryptocaris, 658

Cyinbium, 4SO

Decadocrinus, 160

Constellaria, 276

Cryptoceras, 524

Cymbophora, 420

Decadopecten, 381

Conularia, 491

Cryptochiton, 435

Cymella, 392

Defrancea, 264

Convexastraea, 90

Cryplochorda, 481

Cymia. 478

Deiphon, 636

Cophinaceras, 522

Cryptoclvmeiiia, 548

Cypellia, 58

Deiroceras, 528

Coptostyllus, 467

Cryptocoelia, 65

Cyphosoma, 231

Dejanira, 454

Coral liochama, 403

Cryptocoenia, 89

Cypraea, 473

Dekayella, 273

Coralliophaga, 395

Cryptoconus, 482

Cyprella, 647

Dekayia, 273

Coralliuin, 106

Cryptocriims, 184

Cypricardella, 394

Delocrinus, 161

Corbicella, 409

Cryptodon, 460

Cypricardia, 395

Delphinula, 449

€orbicula, 397

Cryptomya, 421

Cypricardinia, 394

Delphinulopsis, 453

Corbis, 409

Cryptonella, 327

Cypricardites, 365

Delthyridea, 332

Corbula, 422

Cryptonymus, 629

Cypridea, 646

Delthyris, 333

Corbulamella, 422

Cryptoplax, 435

Cypridella, 647

Deltoctos, 519

Corbuloniya, 422

Cryptoplocus, 468

Cypridellina, 647

Deltocyathus, 84

Corburella, 393

Cryptopora, 325

Cypridina, 647

Denckniannia, 577

Cordylocrinus, 139

Cryptoschisma, 198

Cypridinella, 647

Dendracis, 95

Corethrium, 688

Cryptozoe, 655

Cyprimeria, 415

Dendricopora, 283

Corimya, 390

Ctenocephalus, 627

Cyprina, 395

Uendrocrinus, 155

Cornucaprina, 401

Ctenoceras, 519

Cypris, 646

Dendrocystites, 186

Cornulites, 253

Ctenocrinus, 147

Cyprosina, 647

Dendrograptus, 114

Cornnspira, 25

Cteiiodonta, 363

Cyprosis, 647

Dendrophyllia, 93

Coroniceras, 575

Ctenostreon, 383

Cyrena, 397

Dendropupa, 496

Coronula, 652

Cucullaea, 365

Cyre.nella, 410

Dendrostrea, 373

Corydalites, 686 Cucullaria, 365

Cyrenoida, 410

Dentalina, 27

Corydaloides, 684 Cucullella, 363

Cyrtactinoceras, 528

Dentalium, 431

Corymbocrinus, 147 Culicocrinus, 139 : Cyrtendoceras, 515

Derbya, 314

Corynel'a, fi ! Cultellus, 419

Cyrtia, 336

Dermatomya, 392

Coschiella, 279 i Culumbellaria, 472

Cyrtidocrinus, 164

Dermatopora, 287

Cosciniuin, 280

Culumbellina, 472 Cyrtina, 335

Deroceras, 579

Oscinopora, 58

Cumingia, 418 Cyrtoceras, 530

Deshayesia, 462

Coscinotrypa, 280

Cunmlipora, 286 Cyrtocerina, 517 Desmeopora, 264

Cosmoceras, 587

Cuphoselenus, 471 Cyrtochilus, 571 Desmidocrinus, 144

Cosmogyria, 576

Cupressocrimis, 137 Cyrtoclymenia, 548

Desmoceras, 569

Costidiscus, 571

Curtonotus, 395 Cyrtocrinus, 170

Desoria, 246

Cottaldia, 230 Cuspidaria, 392 Cyrtodaria, 422

Deutocystites, 182

Cotylederma, 171 Cuvieria, 490 : Cyrtodonta, 365

Diadema, 229

Cranaena, 328 Cyathaxonia, 74 Cyrtodontopsis, 368

Diademopsis, 229

Crangopsis, 659 : Cyathidium, 171 Cyrtolites, 445

Diadiploceras, 524

Crania, 311 < Cyathocriiius, 156 Cyrtopinna, 369

Diadochoceras, 587

Craniella, 311 Cyathodonta, 390 Cyrtopleurites, 560

Diapiesopora, 268

Craniops, 311

Cyathophora, 89 Cyrtopora, 264

Dibnulites, 275

Craniscus, 311

Cyathophycus, 55 ; Cyrtorizoceras, 529

Diaphorites, 579

Craspedites, 581

Cyathophyllum, 76 Cyrtosiceras, 569

Diaplococeras, 556

Craspedochiton, 435

Cyathopora, 89

Cyrtulus, 478

Diapora, 113

Craspedophylhun, 77

Cyathoseris, 91

Cystechinus, 244

Diastonia, 457

INDEX

697

Diastopora, 2r,i iHi.tvt-W... Bchinooudium, 247 Eoscorpiu

Diasiojinriiia, 261
Dicaniara, 341

Dtrrymooen
Dischidi

BohinocarU, Eosphaeroiim, 669

Erliiiiocliauia, 399 Iv.ii,

hiri'lliHints, 305

Uisnna, BIO

Iv-Jiiii(.ci.laris, 231 Iv.lnx-hns, 4f.2

DiriTiis, 400

Disci 11 isca, 310

Kdiiiioconus, 239 KD/<HIH, :',;>

Dicerocardium, 377
Dichocrinus, 1-10

.ucaris, 658
Dis.-iin.h-iiis. 309

Ecliinocorys, 243
Bohlnoereplt, 248

• rinuf, 155

Ephippiocon

Dichograptus, 118 DisHn.ip.sis, 308

Echinocyani'i

Epliippiiiiii, 384

;>ichotrypa, 280 tea, 523
'icranrlla, r,4 I Discitoerras, 523

Echinocyphiin, 232
Echinocystites, 184, 219

Bphippodonta, 411

Epia8t«^r, 2 1 1

' Di.'i-anisiMis, 315 . -''I

Kcliiiioiliadcina, 229

Bpicjm

iMViaiiognius, (532 Discocea, 270

Ecliiiiodiscns, 237

Kpi>i],li..n, -i:;l

Dicranograpuu, ii1.' DtococwM, 519, 584

Echinoencrinus, 185

/•;/.. '///-/m, 828

Di( lanopora, 280 Discoclymenia, 548
Iticiaiinrus, 633 Discocyathns. M

Echinognatbus, 676
Echinolampas, 241

Erato, 473
Eremites, 559

Dicroloma, 470 Dismcytis, 2tH

Echinometra, 232

Kn-iinici-ras, 530

Dicti/iHrros, 518 Wacodermte, 49

Echinoneus, 239

Eretinocrinus, 143

l>irt vndcada, 686 Discofascigera, 264

K.'liinupsis, 231

Kr.-tt.»].t«Tiis, ti7s

Dictyogmptus, ill i Discohelix, 447

Echinospatagus, 245

Eridopnylkim, 77

Dictyonella, 312 Discoidca, 234

Echinosphaerites, 183

Krido]>')ra, 2«10

Dictyonema.! 114 Discophyllitcs, 566

Echinotlinria, 226

Eridotrypa, 277

Dictyophytoli, 55 l)i*;,i,,,i-i'n<i, 265
Dictyopleurus, 232 Discorbina, 30

Echinus, 233 Eriphyla, 395
Echioceras, 575 Ki iptycha, 486

Dictyothyris, 329 Discors, 1 1 2

Ectenocrinns, 152 BriMorlluu, l|--2

Didacna, 412 Discoscaphites, 572

Kctenodesma, 367 Erodona, 422

Didymites, 566 Discosorus, 528 Ectocentritcs, 573 Krvilia, 421

Didymoceras, 588 Disrosparsa, 261 Ectolcites, 559 Krycina, 411

Didyniograptus, 118 Discotrochus, 83 Edaphoceras, 526 Erycinella, 41

Didymoporo, 269
Dielasma, 328

Discotrypa, 278 Edniondia, 362
Uisculina, 329 Kdrioaster, 187

Krynia, frfM
Erymuoceras, 580

Dielasmina, 328

Disj.-ctopora, 113

Egeria, 419

Eryon, 661

Diempterus, 470

Distichioceras, 570

Egeta, 397

Emx, 421

Dignomia, 307

Distichites, 560

Ehrenberqina, 29

•i, 286

Digonioceras, 526

Distoloceras, 588

Eichwaldia, 312

Escharites, 271

Dikelocephalus, 629

Distortrix, 475

Elaeacrinus, 105

Escharopora, 279

Dimeralla, 325

Ditaxia, 267

Elasmostouia, 6i

Ksth.-ria, 640

Dimeroceras, 552

Dithyrocaris, (>57

Elder, 661

Estheriella, 641

Dimerocrinus, 145

Uitremaria, 444

Elea, 271

Estonioceras, 526

Dimorion, 531

Ditretus, 469

Eleutherocrinus, 198

Etallonia, 485, 664

Dimorpharaea, 94

Dittinarites, 560

Eligmus, 374

Etheria, 378

Dimorphastraea, 94

Dittopora, 276

Elkania, 306

Etheridgia, 61

Dimorphina, 28

Di varicella, 408

Ellipsactinia, 110

Etheridgina, 318

Dimorphites, 554
Dimorphoceras, 553

Dolatocrinus, 148
Dolichopte.ron, 367

Ellipsocaris, 658
Ellipsocephalus, 629

Ethmophyllmn, 92
Etoblattina, 683

Dimorphosoma, 471

Dolichoptems, 676

Elpe, 647

Eucalathis, 329

Diinya, 382
Dimyodon, 382

Dolichotoma, 482
Dolium, 474

Elymella, 362
Elymocaris, 656

Eucalyptocrinus, 148
Eucharis, 392

Dinarella, 327

Doniatoceras, 525

Emarginula, 446

Kuchasma, 362

Dinarites, 559

Donacicardium, 407

Embla, 392

Euchilotheca, 490

Dinobolus, 306

Donax, 410

Embolus, 489

Euchirocrinus, 1.J4

Dinoplax, 435

Doricranites, 556

Emileia, 580

Euchrysalis, 457

Dinorthis, 319

Dorse ten sia, 577

Emmonsia, 99

Euciroa, 302

Diodoceras, 526

Doryceras, 562

Emperoceras, 588

Eucladia, 203

Dionide, 625

Dorycrinus, 143

Empidia, 688 i Eucladocrinus, i:',;i

Dionites, 560

Doryderma, 52

Enallocrinus, 150 Euconactaeon, 4S5

Dioristella, 341

Dosinia, 415

Enallohelia, 84 F rvstrs, 6«6

Dionigoceras, 523

Douvilleia, 485

Enantiosphen, 322 Eucnin-.i, _ '

Dipeltis, 687 j Douvilleiceras, 587

Enclimatoceras, 522 l-'.m-ri nn*, 1-15

Diphragmoceras, 514 Douvillina, 313

Encoiloceras, 625 Kurt/fins, 449

lH,ili!iites, 329

Dreisseusia, 386

Encope, 237 Eucystis, 183

Diphyphyllum, 77
Di pill (Ha, 401, 405

Dreissensioinya, 386
Drepanella, 644

Encrinurus, 634 Eucythara, 483
Encrinus, 161, 166 Kiulwi, 63

Diplacomoceras, 585

Drepanites, 560

Eiidoceras, 514 — -" Eudesella. 316

Diploceras, 514
Diplocidaris, 225

Drepnnopterus, 676
Drillia, 482

Endodonta, 498
Endolobus. 524

Eudesia, 332
Eudesicrinus, 170

Diploclema, 262

Drobna, 661 Endothyra, 30

Eudiocrinus, 174

Diploconus, 598
Diplocraterion. 256

Dromiopsis, 665 Engonoceras, 585
Urymotrypa, 283 Enichaster, 244

Eudiscoceras, 5»;o
Eudoxochiton, 436

Diploctenium, 89

Dualina, 362 Eniialaster, 245

Eugaster, 203

Diplodonta, 410 Dumortieria, f>M Enoploceras, 525

Bogeniactinos, 170

Diplograptus, 119 Diiiicanella, 74 Enoplochiton 436

Eugereon, 686

Diplomoceras, 571 Dnr-a, 377 Eiioplocytia, 664

Euhelia, 84

Diplopodia, 230 Dusa, 661

Ensis, 419

Eulinia, 456

Diplopora, 283 Dux, 361

Entalina, 432

Eulimella, -157

Diploria, 88 Dybowskiella, 269

Entails, 431

Etiiiiotria, 33S

Diplosirenites, 560 Dysaster, 242

Enteletes, 319

Eumicrotix, 371

Diplospirella, 340 Dyscolia, 329

Entodesma, 391

Eiuiella, 328

Diplostoina, 64 Dystactella, 361

Entolium, 381

Eunema, 449

Diplostylus, 668

Entoniidella, 647

Eunicites, 254

Diplotheca, 491 Eastonia, 420

Entonris. 64(5

EuoiiiDlialus. 446

Diplothecanthus, 236 Eatonia, 324 Entomocaris. 654 Eupachvcrin'us, nil

Diplotrypa, 275 Eburna, 470
Dipoloceras, 589 Ecbinanthus, 236, 240

Entomoconchus, 647 Kupatagus, 247
Eodiadema, 230 Eupera, 398

Diporula, 288
Dipsaccus, 476
Dipterocaris, 658

Euhinaster, 210
Echinasterella, 210
Echinobrissus, 239

Eophrynus, 679 Euphemus, 445
Eophyton, 121 Euphoberia, 681
Eopteria, 362 Eupbyllites, 567

698

TEXT -BOOK 0$ PALAEONTOLOGY

Enpsammia, 93

Forbesia, 464 j Glauconia, 465 Guembelites. 560

Euractinella, 340

Forbesiocrinus, 164

Glenotremites, 174

Guerangeria, 375

Euraphia, 652

Forbicina, 681

Globigerina, HO

Guettardia, 58

Eurhodia, 240

Fordilla, 362

Glochiceras, 569

Guettardocrinus. 169

Euryale, 203

Fortisia, 486

Gloria, 362

Guilfordia, 448

Eurycare, 628

Fossariopsis, 453

Glossina, 307

Guncllachia, 494

Eurycarpus, 663

Fossarulus, 464

Glossites, 362

Gwynia, 330

Eurychilina, 644

Fossarus, 459

Glossoceras, 516

Gymnites, 557

Eurydictya, 280

Fragilia, 418

Glossograptus, 119

Gyrnnocrinus, 170

Eurymya, 385

Frenula, 331

Glossothyris, 329

Gymnotoceras, 559

Eurynoticeras, 569

Frenulina, 331

Glossotrypa, 270

Gi/pi'Ha, 321

Eurypneustes, 233

Frieleia, 325

Glottidia, 307

Gypidula, 322

Eurypterella, 676

Frondicularia, 28

Glycimeris, 422

Gyronites, 556

Eurypterus, 674

Froudipora, 263

Glycimeris, 366

Gyropleura, 401

Eurysoma, 676

Fulgaria, 480

Glyphaea, 664

Eurystomites, 519

Fulgorina, 686

Glyphidites, 560

Habrocrinus, 143

Eusarcus, 676
Eusiphonella, 64

Fulgur, 477
Fungella, 263

Glvpliioceras, 552
Glyphis, 445

Hadrophyllum, 74
Hagenowia, 244

Euspilopora, 280

Fungia, 91

Glyphocyphus, 232

Haidingerites, 557

Euspirocrinus, 157

Fungocystites, 183

Glyptaster, 145

Halia, 480

Eustoma, 469

Fusetta, 335

Glyptechinus, 233

Halicardia, 391

Eustylus, 456

Fusispira, 457

Glypticus, 228

Haliotis, 443

Euthria, 476

Fustiaria, 431

Glyptobasis, 450

Haliris,- 392

Euthydesma, 362

Fusulina, 32

GJyptocardia, 362

Hallina, 333

Euthyris, 338

Fusus, 478

Glyptocrinus, 147

Hallirhoa, 49

Eutomoceras, 554

Glyptocystites, 185

Halloceras, 522

Eutrephoceras, 526

Gabbioceras, 570

Glyptodesma, 367

Halobia, 371

Euzonus, 682 '

Gadila, 432.

Glyptopora, 280

Halonympha, 393

Evactinopora, 280

Gadinia, 493

Glyptosceptron, 106

Halorella, 324

Exapinurus, 672

Gadus, 432

Glyptoscorpius, 678

Halorites, 554

Exelissa, 469

Galatea, 397

Glyptosphaerites, 183

Halysiocrinus, 154

Exiteloccras, 588

Galaxea, 89

Gnathodon, 420

Halysites, 102

Exogyra, 373

Galenopsis, 666

Gnorimocrinus, 163

Haminea, 486

Galeodea, 474

Gomphoceras, 532

Hamites, 586

Fabella, 411

Galeomma, 411

Gomphocystis, 183

Hammatoceras, 577

Fabularia, 27

Galerites, 239

Gonambonites, 320

Hamulina, 588

Falcilituites, 519

Galeropygus, 235

Goniaster, 208

Hamusina, 450

Falloticeras, 590

Galerus, 461

Goniasteroidocrinus, 146

Hanleya, 434

Faorina, 246

Gammarus, 668

Goniastraea, 87

Haplaraea, 92

Fascicularia, 263

Gamopleura, 489

Goniobasis, 467

Haploceras, 569

Fasciculipora, 263
Fascinella, 467

Gampsonyx, 659
Garantiana, 583

Gonioceras, 528
Gonioclymenia, 548

Haplocrinus, 135
Haplohelia, 84

Fasciolaria, 478

Gari, 418

Goniocoelia, 341

Haplophragmium, 24

Fascipora, 263

Gasterocoma, 155 ,

Goniocora, 86

Haplopleuroceras, 577

Fasiporina, 263

Gastrana, 418

Goniodiscus, 556

Haploscapha, 370

Faunus, 467

Gastrioceras, 552

Gonioloboceras, 551

Haplosmilia, 90

Favia, 87

Gastrochaena, 423

Goniomya, 389

Haplostiche, 24

Favicella, 270

Gaudryceras, 569

Goniophora, 385

Harmocrinus, 148

Favistella, 79

Gaudryina, 28

Goniopliorus, 227

Harpa, 481

Favosites, 99

Gauthiericeras, 5S9

Goniophyllum, 79

Harpactocarcinus, 666

Felania, 410

Gecarcinus, 667

Goniopygus, 228

Harpactor, 687

Fenestella, 281

Geinitzella, 277

Goniosoma, 395

Harpagodes, 471

Fenestralia, 282

Geisonoceras, 518

Goniostropha, 444

Harpax, 382

Fenestrella, 281

Gemellaria, 285

Gonioteuthis, 597

Harpes, 625

Fenes* ora, 282

G<?mma, 416

Goniotrypa, 280

Harpoceras, 578

-o

Gemmellaria, 401

Gonodon, 409

Harpopsis, 4S1

l-ibula, * /

Geinmellaroceras, 574

Goodallia, 395

Harttina, 328

Fibularia, 236

Gemmipora, 95

Gorgonella, 106

Hauericeras, 569

Ficula, 474

Genabacia, 94

Gorgonia, 106

Hauerites, 560

Filicava, 267

Genea, 476

Gosavia, 480

Haugia, 577

Filicavea, 262

Genentomum, 684

Gosseletia, 368

Haustellum, 477

Filicea, 271

Genicopatagus, 248

Gosseletina, 443

Himtkenia, 467

Filicrisina, 262

Gennaeocrinus, 144

Gotlandia, 306

Hecticoceras, 577

Filifascigera, 263

Genota, 482

Gouldia, 397, 416.

Hedenstroemia, 555

Filisparsa, 262

Geocrinus, 144

Grammatodon, 365

Hederella, 261

Fimbria, 409

Geodia, 46

Grammoceras, 576

Hefriga, 661

Fimbriella, 409

Geophilus, 254, 681

Grammostom urn „ 28

Helcion, 442 •

Fimbriothyris, 332

Geoteuthis, 602

Grammysia, 362

Helcioniscus, 442

Fischeria, 397

Gephyroceras, 550

Granatocrinus, 196

Helianthaster, 203

Fissidentalium, 431

Gerablattina, 683

Graphioci'inus, 160

Heliastraea, 86

Fissirostra, 332

Geralinura, 679

Graphoceras, 576

Helicancylus, 588

Fissurella, 445

Geraphrynus, 679

Graphularia, 106

Helicaulax, 471

Fissurel lidea, 445

Gervillia, 370

Graptaeme, 431

Helicoceras, 586

Fissuridea, 445

Geyeroceras, 568

Graptodictya, 279

Helicocryptus, 452

Fissurirostm, 332

Gibbula, 451

Grasia, 242 1

Helicodonta, 495

Fistulana, 423
Fistulipora, 269
Flabellothyris, 332

Gigantoceras, 527
Gigantotermes, 685
Gilbertsocrinus, 146

Grateloupia, 415
Gresslyia, 387
Griesbachites, 554

Helicophanta, 496
Helicopora, 282
Helictites, 560

Flabellum, 84, 489

Gisortia, 473

Grossonvria, 581

Heliolites, 108

Flammulina, 49S

Gissocrinus, 151!

*£rotriania, 395

Heliophyllum, 77

Flemingia, 450

Glandina, 496

Gruenewaldtia, 334

Helioporae, 107

Flemingites, 556

Glandulina, 28

Gryphaea, 373

Helioscidaris, 232

Florianites, 558
Flumincola, 465

Glassia, 334
Glassina, 338

Gryphcu'ostrea, 373
Gryphochiton, 434

Helix, 495
Helmersenia, 308

FlustreUaria, 286

Glaucomya, 417

Grypoceras, 521

Helminthochiton, 434

Foordiceras, 524

Glauconeme, 283 I'Gualtieria, 247

Heloceras, 518-

JNDKX

Helopora, 280 //,,/,•,,...•/,•,,/,, ,„.
H.-iiii-ristia, f,s4 1 l..l.-vct vpus, ±'53

HidMmma, 113
Midtrypa, 276

Kdiiiufkit.'S, 556

Coninokocen

llrniiartlium, 435 II. .In,

Idmmira, •_'•'.:-'

Eonlnekocidai

ll-iniaspis, 673 Holmu-.THS, .VJ1

Idonean

Konlnckodonl

Ili'iniliaciilit. lldlnrrinus, 167

Igocera.f, -\>'<<t

KoninckophyUum, 77

Ilcmicar.limii, ::r,7, 41'J llul.u-vstis, s;i

Ilariona, 240

Kraussia, 333

Ilcinicidiiris, 228 l|..l..rysliu-s, 183

Illaenus, C30

Kraussina, 333

Hemicosinites, 185 i. I".::

Imbricaria, 480

Kn-ischeria, 679

Hemicystites, 187 ilnlnp

Indoceras, 585

Kutorgina, 312

Hemidiadeina, 228 ll,.Iup,-lla, 167

Infraclypeus, 242

Kymatites, 556

Hemidonax, 407 Bolopaeustes, 232

Inoceramus, 370

Ilcillit'lisiis. 17''. llnlnpus, 171

llt'iniiiuictra, 420 lloinalnrrras, 520

liidcnlis, 114
rntrapora, 279

Labiosa, 420
Lacazella, 316

Ht'iningaj.. Hdiiialncriiiiis, li',4

Inversaria, 271

Ijacazina, 26

Hemipatagua, 245 Homaloneura, 684

locrinus, 153

Lachesis, 482

Heinipedina, 899 . Homalonotus, 635

Iphidea, 308

Lacuna, 459

Hemiphragma, _7"> | Homarus, r,<;i

Iphigenia, 419

Lacunella, 459

Hemipbntgmoceraa, 531

Homatoma, 483

Iridina, 378

Lacunina, 459

Hemiplicatula, 384

Homelys, 661

Tsanda, 451

Laevicardium, 412

Hemipneustes, 243

Homerites, 554

Isaster, 244

1 .Hi'vidf iititliinn, 431

Jl>'iti!/>r<niit<-x, 320

Homocrinus, 155

Isastraea, 87

Ijaganum, 237

Heraiptychlna, 329

Homocystites, 185

Iscanotia, 416

oa, 27

Hemisinus, 467

Homoeospira, 337

Ischadites, 67

l.a.u'iMiincrimis, 136

H.Miiithvris, 325

Homolampas, 248

Isehnochiton, 435

Ijagenipora, 288

Hemitissotia, 590

Homomya, 389

Lschnoneura, 683

Laguncula, 463

H"initrvpa, 282

Homothetus, 684

Ischyrodonta, 365

Lahkmina, 306

Hepatiscus, 666

Homotrypa, 273

Isculites, 565

Lambrus, r,,;.;

//- /Judrtctylus, 471
Heptaatylis, <»5
Heraclites, 560

Hoplites, 584
Hoplocrinus, 151
Hoplomytilus, 372

Isidora, 494
Isis, 106
Ismenia, 331

l.ainpania, 470
Lampterocrinus, 145
Lanieria, 239

Hercoceras, 524

Hoploparia, 664

Isoarca, 366

Ijaoma, 498

Hercoglossa, 522

Horioceras, 570

Isocardia, 414

Lapeirousia, 404

Hercynella, 492

Horiostoma, 461

Isochilina, 643

Lapparentia, 464

Hermatostoma, 113

Hormotoma, 444

Isocrimis, 173

Laqueus, 331

Hernodia, 261

Hornera, 262

Isoculia, 362

Lartetia, 464

Herpetocrinus, 153

Huddlestonia, 576

Isodonta, 418

Lasea, 411

HertlM, 174

Hungarites, 557

Isognomon, 370

Laterocava, 262

Hesperiella, 443

Huron ia, 528

Isogramma, 318

Laterocea, 271

Hesperites, 560

Hustedia, 337

Isonema, 458

LaterotuMgera, 262

Heteraster, 245

Hyalaea, 489

Isophlebia, 685

Latimaeandra, 87

Heterastridium, 111

Hyalina, 497

Isopleura, 472

Latirus, 478

Heteroblastns, 197

Hyalostelia, 55

Isorhaphina, 52

Latusastraea, 86

Heterocardia, 420

Hyalotragos, 52

Isorhynchus, 321

Laubella, 443

Heterocentrotus, 232

Hyattella, 338

Isotrypa, 282

Leaia, 641

Heteroceras, 586

Hyattoceras, 564

Itieria, 468

Lecanites, 556

Heterocrinus, 152

Hyboclypeus, 242

Ivania, 443

Lecanocrinus, 163

Heterodiadema", 229

Hvbocrinus, 151

Lecythiocrinus, 158

Heterodiceras, 400

Hybocystites, 187

Jannnites, 5^2

Leda, 363

Heterodictya, 279

Hybocytes, 152

Janeia, 361

Legnophora, 684

Heterodonax, 418
Heterophlebia, 685

Hyboechinus, 222
Hydatina, 486

JdHiTd, 380

Japonites, 557

Leila, 378
Leioderma, 480

Heterophyllia, 79
Heteropora, 266
Heteroporella, 266
Heterorthis, 319

Hydnoceras, 55
Hydractinia, 110
Hydreionocrinus, 160
Hi/driocrinus, 159

Jerea, 49
Jereica, 53
Joannisiella, 410
Joannites, 565

Leiomya, 392
Leiomyalina, 372
Leiopedina, 233
Leiorhynchus, 324

Heterosalenia, 227
Heteroschisma, 431
Heterostegina, 32
Heterotissotia, 590
Heterotrypa, 273

Hydrobia, 464
Hymenocaris, 654
hymenocydus, 34
Hymenophyllia, 88
Hynniphoria, 332

Jouannetia, 424
Jovellania, 529
Jovites, 554
Julopsis, 681
Julus 682

Leiostvnw., 478
Lenita, 238
Lenticeras, 590
LenMcvlites, 32
Lepadocrinus, 187

Hettangia, 407
Hexacrinus, 140

Hyocrinus, 172
Hyolithellus, 490

Juvavella, 327

'

Lepas, 651

Hexameroceras, 531

Hyolithes, 491

Hiatdla, 422

Hypanthocrinus, 149

Hibolithes, 597

Hypechinus, 233

Hiklocfras, .-,71;

Hyperammina, 2?

Himantopterus, 676

Hyperlioceras, J76

Hindella, 338

Hyphantoceras, 587

Hindia, 51

Hypodadiscites, 566 •

Hindsiella, 411

Hypocrinus, 184 ... llostoma, 4W

Lepidion, i.,«,.i

Hinnites, 381
Hippagus, 392

Hypodiadema, 228
Hypothyris, 324

Kellia, 411
Kelliella, 411

Lepidocentnis, 219
Lepidocidaris, 220

Hipparionyx, 314
Hippochrenes, 472

Hypotrema, 384
Hypsipleura, 456

Keyserlinqia, 308
Keyserlingites, 559

Lepidocoleus, 649
Lepidodcnnn, (174

Hipponyx, 461

Hyptiocrinus, 145

Kingena, 331

Lepidodiscus, 187

Hippopodium, 385

Hystatoceras, 590

Kingia, 331

Lepidopleurus, 434

Hippurites, 405

Hysteroceras, 590

Kingites, 556

Lepidospongia, 60

Histioderma, 256

Ihixti-rolithus, 335

Kionoceras, 519

tepidurus, 641

Histricrinus, 140
Hochstetteria, 372

Hystrichoceras, 589

.t

Klipsteinia, 560
Kloedinia, 644

Lepralia, 288
Leptaena, 313

Hoeninghausia, 554
Hoernesia, 370

Ibergiceras, 562
Iberites, 557

Knemiceras, 585
Kochia, 367

teptaenalotia, 317
Leptaenisca, 314

Holaster, 243

Ichtliyocrinus, 163

Kokenella, 444

I.i'/itiH/onia, 313

Holasterella, 55

Ichthyorachis, 283

Koninckella, 340

Leptaster, 208

Holcodiscus, 570

lehthyosarcolites, 403

Koninckia, 96

Leptastraea, 87

Holcospongia, 64

Idiocrinus, 145

Koninckina, 340

Leptella, 313

Leptesthes, 397 j Lithocrinus, 164 : Macoma, 418 Melampus, 493

Leptobolus, 307

Lithodendron, 87

Macraster, 244 Melania. 4C.7

Leptoceras, 571

Lithodomus, 386

Macrocaris, 655

Melanopsis, 467

Leptochiton, 434

Lithogaster, 664

Macrocephalites, 580

Melantho, 463

Leptocoelia, 338

Lithoglyphus, 465

Macrocheilus, 456

Meleagrina, 371

Leptodesma, 367

Lithomantis, 684

Macrochilina, 456

Melia, 519

Leptodomns, 362
Leptodus, 315

Lithophagus, 386
Lithophyllia, 86

Macrocypris, 646

Macrodon, 364

Meliceritites, 271
Mellita, 237

Leptograptns, 118
Leptomaria, 443

Lithopoma, 448
Lithopsyche, 689

Macropeza, 688
Macropneustes, 247

Mdo, 480
Meloceras, 530

Lepton, 411

Lithosialis, 684

Macroscaphites, 571

Melocrinus, 146

Leptophragma, 58

Lithostrotion, 78

Macroschisma, 445

Melonella, 51

Leptophyllia, 85

Litiopa, 459

Macrostylocrinus, 148

Melongena, 476

Leptopoma, 460

Litoceras, 519

Mactra, 420

Melonites, 221

Leptopoterion, 67

Litoricola, 666

Mactrella, 420

Melonoceras, 530

Leptoria, 88
Leptosolen, 419
Leptospisula, 420
Leptostrophia, 313

Littorina, 459
Littorinella, 464
Lituites, 521
Lituola, 24

Mactroderma, 420
Mactromya, 389
Mactropsis, 421
Mactrotoma, 420

Membranipora, 286, 287
Membraniporella, 287
Meneghiniceras, 563
Menipea, 284

Leptoteuthis, 602

Lobantale, 431

Maeandrina, 88

Menophyllum, 76

Leptotrypa, 278

Lobites, 563

Maeneceras, 551

Meonia, 247

Lfjitn.ris, 467

Lobocarcinus, 666

Magas, 333

Meretrix, 415

Leskia, 248

Lobolithes, 183

Magasella, 333

Merista, 341

Leuconia, 493

Lobophora, 237

Magellania, 333

Meristella, 341

Leucozonia, 479

Lobopsammia, 93

Magnosia, 230

Meristina, 338

Leuroceras, 623

Loculipora, 282

Malaptera, 471

Meroe, 415

Leveillaia, 443

Locusta, 684

Malletia, 36t

Mesalia, 465

Lewisiella, 451

Loftusia, 110

Malleus, 372

Mesentiripora, 261

Libitina, 395

Longobardites, 557

Mamilla, 462

Mesites, 187

Libycofteras, 585

Lonsdaleia, 78

Mammites, 588

Mesoblastus, 194

Lichas, 632

Lophoceras, 526, 569

Mandaloceras, 531

Mesoblattina, 684

Lichenalia, 269

Lopholepis, 263

Mangilia, 483

Mesoceras, 516

Lichenopora, 264

Lopholobites, 590 ! Mannia, 333

Mesodesma, 421

Lichenotrypa, 270

Lophonotus, 682 Manticoceras, 550

Mesothyra, 657

Liebea, 372

Lophophyllum, 76 I Maretia, 247

Mesotreta, 308

Ligula, 390

Lophoseris, 91 Margarita, 451

Mesotrypa, 273

Lillia, 577

Lophosmilia, 89 Margarites, 554

Mespilocrinus, 164

Lima, 383

Lophospira, 444 Margarya, 463

Metablastus, 195

Limacina, 489

Lorica, 436

Marginaria, 287

Metacanthoplites, 589

Limaea, 383

Loricella, 436

Marginalia, 479

Metacoceras, 524

Limanomia, 384

Loricites, 434

Marginifera, 317

Metacrinus, 173

Limatula, 383

Loricula, 650

Marginulina, 27

Metalia, 247

Limax, 497

Loriolaster, 207

Mariacrinus, 147

Metaplasia, 337

Limnaea, 494

Loripes, 408

Marmolatella, 453

Metaporhinus, 242

Limnaeus, 494

Lotorium, 474

Marsupiocrinus, 139

Metasibirites, 558

Limnocardium, 413

Lottia, 442

Marsupites, 165

Metatirolites, 559

Limopsis, 365

Lovenia, 247

Martesia, 424

Metopaster, 208

Limopteria, 371

Loxoceras, 527

Mastigocrinus, 157

Metoptoma, 442

Limidoides, 673

Loxonema, 456

Matercula, 367

Metriophyllum, 76

Limulus, 672

Loxopte-ria, 367

Matheria, 365

Metula, 476

Linckia, 210

Lucapina;, 415

Matheronia, 400

Meyeria, 664

Lindigia, 586

Lucapinella, 445

Mathilda, 457

Michelinia, 101

Lindstroemella, 310

Lucina, 408

Matthewia, 491

Mickwitzia, 307

Lindstroemia, 75

Ludwigia, 576

Matuta, 666

Micrabacia, 94

Linearia, 417

Luidia, 208

Mazza, 479

Micraster, 246

Lingula, 307

LumbricHria, 254

Mazzalina, 479

Microceras, 578

Lingulasma, 308

Lumbricites, 254

Mecochirus, 662

Microconchus, 253

Lingulella, 307

Lunatia, 462

Mecynodon, 394

Microcyclus, 75

Lingulepis, 307

Lu n ul i card i urn, 367

Mecynostoma, 686

Microcyphus, 232

Lingulina, 28

Lunulites, 285

Medlicottia, 563,

Microderoceras, 578

Lingulocaris, 655

Lunuloceras, 577

Medusaster, 210

Microdiadema, 229

Lingulodiscina, 310 ; Lutetia, 411 1 Medusites, 121

Microdicus, 625

Lingulops, 308 ! Lutraria, 420 ; Meekella, 315

Microdoma, 450

Linnarssonia, 308 Luzonia, 393 ] Meekia, 407

Microdon, 394

Linthia, 246

Lychnus, 497 ! Meekoceras, 556

Micromaia, 666

-Limrnarus, 663

Lycodes, 376 Mee'io-jora, 270

Micromelania, 464

LioceraSTol l^tcoDhoria °01 ' Meaacvstitt. '. " "

Micromelo, 486

Lioclema, 277

Lycopffrfr, :i4

Megalanteris, 327

Micropedina, 230

Liolophura, 436

Lyonsia, 397

Mfualaspis, 630

Micropocrinus, 171

Liopistha, 392

Lyonsiella, 391

Megalithista, 52

Micropora, 287

Lioplax, 463

Lyra, 331

Megalodon, 376

Microporella, 288

Liothyrina, 329

Lyria, 480

Megalomostoma, 460

Micropsis, 231

Liothyris, 329

Lyriocrinus, 146

Megalomus, 365

Microschiza, 456

Liotia, 449

Lyriopecten, 380

Me'ganeura, 684

Microseris, 91

Liparoceras, 578

Lyrodesma, 378

Meganteris, 327

Microsolena, 94

Liropteria, 370

Lyropora, 282

Megaphyllites, 566

Microthorax, (166

Lisgocaris, 658

Lysis, 478

Megaptera, 368

Microthyris, 332

Lispoceras, 523

Lyticoceras, 586

Megaspira, 496

Microtropites, 554

Lispodesthes, 471

Lvtoceras, 572

Megatebennus, 445

Mila, 367

Lissoceras, 569

Lyttonia, 315 ! Megateuthis, 597

Miliola, 26

Lissochilus, 454

Megathentomum, 684

Millepora, 109

Lithacoceras, 581

Macandrevia, 331 Megathyris, 330

Millericrinus, 169

Litharaea, 96

Macha, 419 Megerlia, 331

Milleroceras, 530

Lithentomum, 684

Machilis, 683 Megerlina, 333

Milneria, 399

Lithobius, 681

Machomya, 389 Megistocrinus, 144

Miltha, 408

Lithocardium, 413

Maclurea, 446 Meiocardia, 414

Miltites, 554

INDEX

7"!

Mimoceras, 549 .Ui/"/

Nonioniua, 34 Ophiilioiifr.,

Mininrvstiii's, 185

Myriami.

Xorella, 324

Ophilt-ta, 44.;

Miimilus, 315

\...,irs,563

Ophioceras, 575

.Mischoptera, 684

M\ rid/diiiii 289

Xnnnaiiiiitrs, 580

Ophiocrinus, 158, 174

Mitra, 47'.'

.W'>/ri*tii-i> 17ii

Nostoceras, 588

Opliioctcn, 20:,

Mitraefusus, -170

M \niiar, 690

Xotainia, 285

Ophiodantiti ''04

Mitraster, 20S
Mitroclema, 2.12

.M \rt.-a, ION
MyrtiUocrinuB, 137

Nothoceras, 532
Nothozoe, 655

Opl.ioglyph'u~205
Ophiolepis, 20:,

Mitrocystitea, 186

Mysi.lia, 372

Notothyris, 32:i

Ophioiniisiiiiii, 205

Mixotiphonocenw, •'••-".'

Myttrophora, 320

Xovaculina, 419

OphiraphiditM, 46

Modelia, 4 is

Mvtitaiva, 868

Nubecularia, 25

Oj.hiura, 204

Modiella, 372

Mytilops. 372

Nucleatula, 327

Ophiurella, 205

Modiola, 386

Mvtilopsis, 3SC,

Nudeocrinus, 195

Opis, 3!»ii

Modiolaria. 3s.;

Mytilus, 3sr,

Nucleolites, 239

Opisoma, 395

Modiolod'

Xucleospira, 338

Upisthojitera, 368

Modioloid(
Modiolopsi

Modiomorplia, 385

Xacella, 442

Xait.-s, 256
Xaunites, 553

Xucula, 363
Nuculatut, 363
Xuculina, 364

Oploplorus, tit',1
Oppelia, 577
Orbicella, 308, 309

Mn-ulia, li:.

Namio, 515

Nunimuliiia, 33

Orbiculina, 25

Mohrensternia, 464

Naiiocrinus, 155

Xinninulites, 32

Orbiculoidea, 310

Moira, 246

Xaranaio, 417

NutUillina, 435

Orbipecten, 380

Moiropsis, iMi'>

Narthecoceras, 515

Nyassa, 375

Orbitoides, 34

Alnjsisovic-sia, 500

Xassa, 47f>

Nyctopora, 99

Orbitolina, 24

Mojsvarites, 566

Xatii-.il, 462

Nymphaeops, 664

Orbitolites, 25

Moltkia, 106

Xaiicdla, 453

Nymphaster, 208

Orbulina, 30

Monia, 384

Naticopsis, 452

Nystia, 461

Oreaster, 2os

Monobolina, 310

Xatiria, 453

Oriostomu, 447

Monoceros, 478

Naucoris, 687

Obolella, 305

Uriskania, 326

Monodacna, 413

Nautilus, 52^6 '

Obolellinvi, 306

Ormoceras, 528

Monodonta, 451

Xayadites, 374

Obolus, 306

Ornithaster, 246

Monograptus, 117

Neaera, 392

Ochetoceras, 569

Ornithella, 332

Monomerellia, 306

Neatretia, 325

Ocinebra, 477

Orocystites, 184

Monophyllilcs, 666

Nebalia, 654

Otameroceras, 531

Orophocrinus, 198

Monopleura, 401

Necrocarciims, 666

Octonaria, 645

Orozoe, f,,r,i;

Monoporella, 288

Necrogaminarus, 668

Oculina, 84

Orthambonites, 319

Monoprion, 117

Necroscylla, 660

Oculospongia, 64

Orthaulax, 472

Monopteria, 371

Nectotelson, 659

Odontoceras, 587

Orthidium, 315

Monotis, 371

Neithea, 380

Odontoperna, 370 .

Orthis, 319

Monotrypa, 275

Nemapodia, 256

Odontostoma, 457

Orthisina, 320

Monotrypella, 378

Nematopora, 281

Odontotrypa, 270

Orthoceras, 518

Monticulipora, V72

Nematura, 464

Oecoptychius, 583

Orthocidaris, 225

Montlivaultia, 85

Nemertites, 256

Oecotraustes, 577

Orthodesina, 361 .

Mopalia, 435

Nemodon, 365

Oedischia, 683

Orthodontiscus, 393

Morio, 474

Neobolus, 306

Oehlertella, 310

Orthoidea, 332

Morphoceras, 583

Neocatillus, 370

Offa, 647

Orthonomctea, 333

Morrixia, 330

Neocatopygus, 240

Offaster, 243

Orthonota, 361

Mortoniceras, 589

Neoicoceras, 550

Ogygia, 630

Orthonychia, 460

Moulinsia, 236

Neolampas, 242

Ohiocrinus, 152

Ortkopora, 281

Mourlonia, 443

Neolimulus, 672

Oldhainia, 315

Orthopsis, 230

Mucronella, 288

Neolobites, 585

Olenellus, 628

Orthoptychus, 402

Muehlfeldtia, 331

Neorthroblattina,- 684

Olenikites, 559

Orthorhynchula, 323

itcvrt^ps ii(>.)

\eoschizodi'" 9"f>

Olenus, 628

Ortlwtnma, 485

o. uiictiini,'- •

jfffif er"c';"'«.s, - 'rvas,.6s7" . ,:'::uT"a"^, 558
Muller * 1 ^^tSy^^^-~^\Pseiidocerithium, 469

Pinicturella, 440
Pupa, 4!>6

Mvttetin'tml 1 T^ePhriticera,a m ""^aeudochaetetes, 103
Multel \ eP'lrops QQA / Op*"^1"8' 228^-"-

Pupillaea, 445

I1 If K

fw&- fe?a* M3as5£

fcna5' 3-Sr / ^toSiS453452 I 0,?/hy^ 7°7 ' ^

" S^s;-s--

te
»

j^yo-tinodonm $*•-, Vein ''"* "a' ^® 1 ^nc°ceras rq' ^ 1 X"/"^°'J)a, 4i>o
MS^*^. 372 ^veri&f7 S^*"^ 454 OvuS°'"aA 454

-

-

'", 377

702

TEXT -BOOK OF PALAEONTOLOGY

Pachymytilus, 386 ' Paradoxechinus, 232 Pericyclus, 552 Phyllocrimis, 171

Pachyphyllum, 79

Paradoxides, 627

Periechocrinus, 144 Phyllodictya, 2SO

Pachypoma, 448
Pachypora, 99

Paragymnites, 557
Parajuvavites, 554

Peripetoceras, 525 Phyllodocites, 256
Peripleurites, 561 Phyllograptus, liy

Pachypteria, 382

Parakymatites, 556

Periploma, 390 1'liyllonotus, 477

Pachyrhynchus, 333

Paralampas, 240

Periplomya, 389 Phyllopora, 283

Pachyrisma, 377

Paralecanites, 556

Peripneustes, 247 Phylloporina, 283

Pachystroma, 112

Paralegoceras, 552

Peripora, 202 Phyllosniilia, 89

Pachyteichisma, 59

Paralenticeras, 590

Perischodomus, 220 Phylloteutliis, 003

Pachyteuthis, 597

Parallelodon, 364

Perisphinctes, 581 Phymatella, 48

Pachytylodia, 64

Paramelania, 467

Peristernia, 479 Pliyinatoceras, 577

Palaeacis, 95 '

Paramya, 422

Perna, 370 Phymechinus, 230

Palaeastacus, 664

Paranomia, 384

Pernopecten, 380 Physa, 493

Palaeaster, 207

Paranorites, 556

Pernostrea, 370 Physetocrinns, 142

Palieechinus, 221

Parapachydiscus, 570

Peronella, 63 Physocaris, 655

Palaega, 669

Paraphyllites, 549

Peroniceras, 589 Physodoceras, 582

Palaemon, 661

Parapopanoceras, 564

Peronidella, 63 Phytogyra, 91

Palaeoblattina, 683

Paraprolecanites, 563

Peronoceras, 579 Pictetia, 588

Palaeobrissus, 248

Parapronorites, 563

Peronopora, 272 Pictonia, 581

Palaeocampa, 681

Paraprosopon, 659

Persona, 475 Pileolns, 454

Palaeocardia, 368

Parapsiloceras, 574

Petalaxis, 78 Pileopsis, 460

Palaeocardita, 398

Pararca, 363

Petalia, 685 Pileotrypa, 269

Palaeocaris, 659

Parastarte, 416

Petaloconchus, 466 Pileus, 234

Palaeocarpilius, 666

Parastephanites. 558

Petalophora, 263 Piloceras, 515

Palaeocidaris, 220

Parastrophia, 321

Petalotrypa, 278 Pimelites, 579

Palaeoclymenia, 519

Parathisbites, 560

Petenoceras, 524 , Pinacoceras, 661

Palaeocoma, 207

Paratibetites, 560

Petersia, 472 . Pinacophylluni, 89

Palaeocorbis, 409

Paratornoceras, 551

Petigopora, 274 ! Pinacotrypa, 270

Palaeocorystes, 666

Paratropites, 554

Petraia, 74

Pinna, 369

Palaeocrangon, 659

Parazyga, 338

Petraster, 207

Pinnacites, 550

Palaeocrania, 311

Parisocrinus, 158

Petricola, 417

Pinnatopora, 283

Palaeocreusia, 652

Parkeria, 110

Petrobius, 683

Pinnigena, 309

Palaeocrinus, 155

Parkinsonia, 583

Pexidella, 340

Pinnocaris, 058

Palaeocylus, 74

Parmacellina, 496

Phacites, 32

Pioneerings, 143

Palaeocypris, 646

Purmophorus, 440

Phacoceras, 523

Pisanella, 475, 479

Palaeocystites, 184

Paroniceras, 575

Phacops, 636

Pisidium, 398

Palaeogamniarus, 668

Paropsis, 371

Phaenopora, 279

Pisocrinus, 135

Palaeogoniatites, 549

Paryphostoma, 457

Phaenoschisina, 197

Pithodea, 450

Palaeograpsus, 666

Pasceolus, 67

Phalangiotarbus, 679

Placenta, 384

Palaeolampas, 242

Passyia, 411

Phanerotinus, 446

Placenticeras, 585

Palaeoinanon, 50

Patella, 442

Phanogenia, 175

Placiphorella, 435

Palaeomutela, 374

Patellina, 31

Pharciceras, 554

Placites, 561

Palaeomya, 407

Paterina, 305

Pharella, 419

Placocoenia, 89

Palaeonarica, 453

Paterula, 307

Plutretrella, 491

Placoparia, 634

Palaeoncmtilus, 519

Patrocardium, 367

Phasganocaris, 655

Placophoropsis, 435

Palaeoneilo, 363
Palaeoniso, 457 .

Pattersonia, 55
Pavonaria, 106

Phasianella, 448
Phasianus, 448

Placophyllia, 89
Placopsilina, 23

Palaeopemphix, 659

Pecchiolia, 392

Phasis, 498

Placosmilia, 89

Palaeophiura, 203

Pecten, 380

Phenacolepas, 446

Placutia, 3S4

Palaeophonus, 679

Pectunculus, 300

Pliialocrinus, 162

Placunanomia, 384

^alaeopinna, 369

Pedicularia, 473

Phiddophora, 289

Placunemn. 3S,4

T>*NiQJ)n(iUStes 9^ i

Pedina, 230

Philinc, 4*7

Y'i. .. 384

^*^._' _^-^"^

Plaesiomys, 319

Palaeosaccus, 55
Palaeosceptron, 106
Palaeosolen, 419
Palaeostella, 207
Palaeostoma, 248
Palaeotropus, 248
Palasterina, 207
Palasteriscus, 207

Pedioceras, 5S>'
Pedum, 381
Peismoceras, 520
Pelagia, 264
Pelanechinus, 226
Peltarion, 452
Peltastes, 227
Peltocaris, 658

Phillipsastraea, 79
Phillipsia, 631
Philobrya, 372
Philocrinus, 160
Phiniocrinus, 136
Phloioceras, 523
Phlycticeras, 569
Pholadella, 388

Plagiodon, 37S
Plagioglypta, 432
Plagioptychus, 40 1
Plagiostoma, 3S3
Planaxis, 459
Planctoceras, 519
Planetoceras, 5J3
Planocephalus, 683

Paleanatina, 362
Palearca, 365

Peltoceras, 582
Pemphix, 664

Pholadocaris, 658 Planolites, 256
Pholadomya, 389 Planorbella, 489

Palescliara 283

Penaeus, 661

Pholas, 423 , Planorbis, 494

Palingenia,' 684
Palinurina, 663

Peneroplis, 25
Pennatulites, 106

Pholidocidaris, 222 Planorbulina, 30
Pholidophyllum, 77 Plaiiulina, 30

Palinurus, 003
P.allium. ?81

Penniretepora, 283
Pentaceros, 208

Pholidops, 311 Plasinopora, 108
Pholidostrophia, 313 Platidia, 330

Paii.opKiuroceras, 577
Paludina, 463

Pentacrinus, 173
Pentactinella, 339

Phormedites, 560 i Platyacra, 450
Phorinosella, 55 Platybrissus, 245

Panda, 495
Pandora, 390

Pentagonaster, 208
Pentagonia, 341

Phorinosoma, 226 ' Platyceras, 401
Phorus, 463 Platychilina, 453

Panopaeus, 666
Panopea, 422
Paolia, 683

Pentamerella, 322
Pentanieroceras, 531 -"
Pentamerus, 321

Plios, 476
Phragmoceras, 532
Phragmoteutliis, 599

riatvcnonia, 02
Platyclymenia, 548
Platycrinus, 138

Paphia, 421
Papyri dea, 412
Paracardium, 362
Paraceltites, 553
Paraceratites, 559
Paracladiscites, 566
Paracochloceras, 561
Paractinoceras, 528

Pentaphyllum, 76
Pentastere, 321
Pentata, 302
Pentephyllum, 198
Pentremites, 194
Pentremitidea, 194
Pephricaris, 656
Peregrinella, 325

Phragmotlieca, 491
Phreatura, 645
Phricodoceras, 587
Phrynns, 679
Phryssonotus, 682
Phthanocoris, 686
Phthonia, 301
Phyllangia, 86

Platylenticeras, 590
Platymya, 389
Platyodon, 421
Ptafcypleuroceras, 578
Platyscliisma, 440
Platystoma, 461
PJatystrophia, 319
Plaxiphora, 435

Paracyathus, 84

Pereiraea, 471

Phyllobrissus, 241

Plecamuni, 2S

Paracyclas, 407

Pergamidea, 372
Pericosma, 246

Phylloceras, 567
Phyllocoenia, 90

Plecotrema, 493
PlectambonitP.s, 313

INDKX

Plectoceras, 520

I'olyx.-ii' Prososthenia, 464

Plectoderma, 55

1'uiiiat ia>.. li'iii

Proaphingites,

I'silothorax, 684

Plectodon, ::'.•::

Pomatograptus, 117

Protalochiton, 431

r>ilotissotia.

I'l.M't "111 \"1 ">S'I

I'omatosiiiirlla, 340

Protaraea, 96

Pteria, 370

Plectorthis, :',!'.»

l'nntoc\ |,i is. 6|«;

Protaster, 203

Pterinea, 367

ricsianthus, 2:17

Popanoceras,

Protasteracanthion, 210

ii 380

Plesiastraea, 87

1'onunl.oiiitcs, 321

Protengonocerat

Pterocai;

Plesiocyprina

r.irc.'llia, 44:;

Proteocystites, 183

Pterocera, 471

I'or.-lla, 288

Protetraclis, 47

Pterocerella, 471

Flesiolampaa, 242

1'orina, 2ss

Protetragonites, 569

I'U-n, chiton, 434

I'l.'sioU'iithis, 003

Porites, 96

Prothyris, 361

Pterocoinu, 174

Plesiothyris, 332

Porocrinus, 1st

Proto, 465

Pterodonta, 471

Plesiotiss.it ia, .O'.M)

Poroinya, 392

Protobactrites, 518

Pteronautilus, r,2".

I'lrthuinytilus, ::.is

1'. iro-phacra, 111

Protobalanus, 052

Pteronites, 370

Porospougia, ;09

Protocardia, 412

Pteronotus, 477

I'li't/tiirlt u tti'li'i ">'' t

Portlockia, 459

Protocaris, 041

Pteroperna :>7l

Pleuracanthitee

Portunites, 666

Protocimex, f,so

Pterophloios, 316

Pleurocera, 467

Posidoniella, 372

Protocrinites, 183

Pteropsis, 420

CO, ">T7

Posidonomya, 371

Protocrisina, 262

Pterotheca, 491

Pleurocora, M;

Potamides, 469

Protocycloceras, 518

Pterotocrinus, 140

Pleurocvstib's. L86

Potamomya, 422

Protodiceras, 377

Pterygometopus, 63(5

Pleurodiadt-ina, 2:',0

Poterioceras, 530

Protolimulns, 671

Ptcrygotus, f,77

Pleurodictyimi, 100

Potoceras, 525

Protolycosa, 680

Ptilodictya, 27!»

Pleurodonta, 362

Pourtalesia, 248

Protoma, 465

Ptilopora, 283

Pleurodonte, 495

Praearcturus, 668

Protoinya, 362

Ptiloporella, 288

Pleurolytoceras, 572

Praeatya, 662

Protonerita, 453

Ptiloporina, 283

Pleuromeris, 899

Praecardium, 362

Protonia, 317

Ptilotrypa, 279

Pleuroniya, 387

Praelima, 362

Protopharetra, H2

Ptycliarcestf-.

Pleuronautilus, 525

Praelucina, 362

Protophasma, ('>*'.!

Ptychites, 557

Pleuronotits, 440

1'rarsphaeroceras, 579

Protophiceras, 556

Ptychocaris, 650

Pleuropaohydiscus, 571

Prasopora, 273

Protophragmoceras, 532

Ptychoceras, 571

Pl.'iiropliorus, 394

Preconia, 395

Protorhyncha, 323

Ptychocrinus, 145

Pleurorhynchva, 369

Prenaster, 240

Protorthis, 312

Ptychodesma, 372

Pleurostoma, 5S

Prestwichia, 671

Protoschizodus, 395 Ptychomphalns, 443

Pleurotoma, 482

Priamus, 480

Protospongia, 55

Ptychomya, 397, 416

Pleurotomaria, 443

Primitia, 644

Protosycon, 65

Ptychonema, 275

Plicatocrinus, 171

Primnoa, 106

Protozyga, 333

Ptychoparia, 628

Plicatula, 382

Prionastraea, 87

Protrachyceras, 560

Ptychophyllum, 78

Plicigera, 339

Prionites, 556

Proutella, 283

Ptychospira, 337

Plicomya, 389

Prionocyclus, 589

Psammechinus, 233

Ptychostoma, 456

Plinthosella, 49

Prioiiolobus, 556

Psammobia, 418

Ptychostyhis, 467

Pliorhytis, 418

Prionotropis, 589

Psamiiiocarcinus, 666

Ptygmatis, 468

Plococeras, 556

Priscochiton, 434

Psammohelia, 84

Ptyssoceras, 524

Plocophyllia, 90
Plocoscyphia, 61

I'risiuopora, 280
Pristiograjitus, 117

Psammosolen, 419
Psammospaera, 23

Puella, 362

J'li'/itt'a, 329

Plumaster, 208

Proarcestes, 565

Pselioceras, 525

Pugiunculus, 491

Plinnulites, 649

Proavites, 556

Psephis, 416

Pugnax, 324

Pocillopora, 84

Probeloceras, 550

Pseudalaria, 469

Pugnellus, 471

Poculina, 489

Probolaeum, 434

Pseudamusiuni, 381

Pugnus, 486

Podocidaris, 232

Proboscidella, 318

Pseudastacus, 664

Pullastrii, Hi:

Podocrates, 663

Procardia, 389

Pseudedmondia, 407

rii!s,-l/nm, 432

Poecilasma, 651

Procerites, 581

P-seuderiphyla, 397

Pulvinulina, 30

Poecilomorphus, 576

Procladiscites, 566

Pseudobelus, 597

Punctum, 49S

Poliochera, 679

Prodryas, 689

Pseudoceltites, 558

Puncturella, 446

Polioptenus, 683

Productella, 317

Pseudocerithium, 469

Pupa, 496

Pollia, 475

Productus, 317

Pseudochaetetes, 103

Pupillaea, 445

Pollicipes, 650

Proetus, 631

Pseudocidaris, 228

Purpura, 477

Polorthus, 424
Polyblastidium, 60

Progonoblattina, 683
Prographularia, 106

Pseudocrbigon, 661
Pseudocrania, 311

Purpurina, 458
Purpuroidea, 458 .

Polycidaris, 225

Projovellania, 529

Pseudocrinites, 187

Pustularia, 4.07

Polycheles, 661

Prolecanites, 562

Pseudodanubites, 557

Pustulopora, 262

Polycnedium, 665

Prolibythea, 689

Pseudodiadema, 229

Puzosia, 569

Polycoelia, 63, 74

Prolobella, 385

Pseudodiceras, 400

Pycnaster, 208

Polycyclus, 561

Prolobites, 549

Pseudodinarites, 559

Pycnodonta, 373

?olycyphus, 230

Prolucina, 408

Pseudofossarus, 453

Pycnomphalus, 451

olydonta, 451
Polygonosphaerites, 67

Promachocrinus, 175
Promacrus, 361

Pseudogalathea, 659
Pseudoglyphaea, 664

Pycnophylluin, 76

Pyconosaccus, 164

Polygyra, 495

Promathilda, 457

Pseudohaplocfiras, 570

Pygaster, 234

Polyjerea, 49

Promedlicottia, 5(53

Pseudoharpoceras, 559

Pygaulus, 239

Polylepas, 650

Pronannites, :> 2

Pseudohydrophilus, 687

Pygocardia, 395

Polymorphina, 28

Pronites, 320

Pseudoliva, 475

Pygocephalus, 659

Polymorpliites, 574

Pronoe, 415

Pseudomelania, 456

Pygolampis, 084

Polyodonta, 493

Pronoella, 415

Pseudomonotis, 371

Pygope, 329

Polypeltes, 147

Pronorites, 563

Pseuilonautilus, 522

Pygurus, 241

Polyphemopsis, 457

Propeamusium, 381

Pseudonerinea, 468

1'yrainidella, 457

Polyplectus, 577

Prophysaon, 498

Pseudoniscus, 673

Pyiamidula, 498

Polypora, 282
Polyptychites, 583

Propinacoueras, '•>'.:>,
Proplanulites, 581

Pseudopedina, 230
Pseudophyllites, 569

I'ynixus, 470
Pyrenella, 470

Polyschides, 432

Propteticoa, 684

PseudoplcKWia, 384

J'/i/'i/ia, 101

Polystomella, 34
Polytoechia, 320

Proptychites, 556
Propygopc, :i2i>

Pseudosageceras, 555
Pseudoscalites, 4. OS

Pyrgidium, 4i',4
Pyrgoma, 652

Polytrema, 31

Proricaris, t;:.s

Pseudotoma, 482

Pyrgula, 464

Polytremacis, 107
Polytremaria, 444

Prorokia, 395
Proscorpius, 679

Pseudotropites, 577
Psiloceras, 574

Pyrgulifera, 467
Pyrina, 239

Polytremata, 266

Prosocoelus, 395

Psilocladiscites, 566

I'vriioii. ma, 55

Polytropis, 447

Prosodocna, 413

Psilodon, 413

Pyrocystites, 182

704

TEXT -BOOK OF PALAEONTOLOGY

Pyrula, 474, 476

Rhodaraea, 96

Scaldia, 407

Semiplicatula, 384

Pythina, 411

Rhodea, 496

Scalites, 458

Semitubigera, 263

Pythiopsis, 493

Rhodocrinus, 145

Scalpellum, 650

Senectus, 448

Pyxis, 317

Rhodophyllum, 78

Scambula, 397

Sepia, 601

Quenstedtia, 101, 418
Quenstedtoceras, 580
Quinqueloculina, 26
Quoyia, 459

Rhoechinus, 221
Rhombifera, 137
Rhombina, 647
Rhombopora, 281
Rhombopteria, 367

Scapha, 480
Scaphander, 487
Scaphanidia, 452
Scapharca, 366
Scapheus, 662

Septameroceras, 531
Septifer, 386
Septopora, 283
Seraphs, 471
Seriatopora, 84

Rachura, 657

Rhopalocoma, 207

Scaphiocoelia, 326

Serietubigera, 263

Radiocavea, 264

Jihopia, 210

Scaphiocrinus, 159

Serpula, 253

Radiofascigera, 264

Rhynchidia, 452

Scaphites, 572

Serpulites, 253

Radiolites, 404

Rhynchomya, 389

Scaphula, 366

•Serripes, 412

Radula, 383

Rhynchonella, 324

Scarabaeides, 687

Sestromostella, 64

Ratinesquina, 312

Rhynchonellina, 324

Scarabus, 493

Setosella, 287

Ramipora, 283

Rliynchopora, 324

Scenella, 442

Sibirites, 558

Ranella, 475

Rhynchoporina, 324

Scenellopora, 268

Sicanites, 563

Rangia, 420

Rhynchora, 333

Scenidium, 320

Sieberella, 322

Raniella, 665

Rhynchorina, 333

Sceptropora, 281

Siemiradzkia, 582

Ranina, 664

Rhynchorthoceras, 521

Schistoceras, 552

Sigaloceras, 587

Raninoides, 665
Rapana, 478

Rhynchospira, 337
Rhynchostreon, 373

Schistophylloceras, 568
Schizambon, 309

Sigaretus, 462
Silbyllites, 554

Raphistoma, 443

Rliynchotrema, 323

Schizambonia, 309

Mlenia, 392

Raphistomella, 443

Rhynchotreta, 323

Schizaster, 246

Silesites, 570

Raphitoina, 483

Rhyphus, 688

Schizoblastus, 196

Silia, 481

Rastrites, 118

Rhytimya, 388

Schizobolus, 310

Siliqua, 419

Receptaculites, 67

Ribeiria, 654

Schizochiton, 436

Siliquaria, 466

Reckur, 660

Richthofenia, 319

Schizocrania, 309

Silurina, 363

Redonia, 362, 363

Ricinula, 478

Schizodentalium, 431

Simbirskites, 583

Regina, 302

Rimella, 472

Schizodesma, 420

Simoceras, 582

Reiflingites, 559

Rimula, 446

Schizodiscus, 443, 641

Siphonalia, 476

Reineckia, 583

Ringicula, 486

Schizodus, 379

Siphonentalis, 432

Remeleoceras, 526

Ringinella, 486

Schizogonium, 444

Siphonia, 49

Reinondia, 379

Rissoa, 465

Schizopholis, 312

Siphonocoelia, 63

Reinopleurides, 628

Rissoina, 465

Schizophoria, 319

Siphonodentalium, 432

Rensselaeria, 326

Rithma, 684

Schizoplax, 435

Siphonotreta, 309

Remselandia, 326

Rizoceras, 529

Schizoporella, 289

Sirenites, 560

Reptaria, 261

Rocellaria, 423

Scliizorliabdus, 60

Sismondia, 236

Reptelea, 271

Roemeraster, 210

Schizosia, 402

Sistrum, 478

Reptocea, 270

Roemerella, 310

Schizostoma, 446

Slimonia, 676

Reptofascigera, 263

Romingeria, 101

Srhizothaerus, 420

Smilotrochus, 83

Reptotubigera, 262

Romingerina, 326

Schizotreta, 310

Smittia, 288

Requienia, 400

Rostellaria, 472

Schloenbachia, 589 ! Solanocrinus, 174

Retecava, 262

Rostellites, 480

Schlotheimia, 574 Solariella, 451

Retelea, 271

Rotalia, 30

Schlueteria, 569

Solarium, 446, 458

Reteocrinus, 144

Rotella, 451

Schmidtia, 306

So'.aster, 210

Retepora, 289

Rotellina, 451

Schroederoceras, 519

Solecurtus, 419

Reticulipora, 262

Rothpletzia, 461

Schwagerina, 32

Solemya, 361

Retiograptus, 119

Rotula, 238

Scintilla, 411 Solen, 419

Retiolites, 119

Roualtia, 482

Scipionoceras, 571 Solenastraea, 87

Retusa, 487

Roudairia, 394 .

Sclerocrinus, 170

Soleniscus, 457

Retzia, 337

Rinnina, 496

Scolecodenna, 256

Wolenocaris, 655, 656

Rhabdammina, 23

Runa, 236

Scoliostoma, 458

Solenocheilus, 525

Rhabdoceras, 561

Rupertia, 31

Siiolithus, 256

Solenopsis, 361

Rhabdomeson, 281

Rutoceras, 522

Scolopendra, 681

Solidula, 484

Rhabdophyllia, 87

Rut.itia, 371

Scorisia, 474

Sollasia, 65

Rhabdopleura, 459 Ryticeras, 522

Scrobicularia, 418

Somatogyrus, 460

Rhabdus, 431

Scrnparia, 285

Sonneratia, 584

Rhacodiscula, 49 Saccammina. 23

Scrupocellaria, 284

Sonninia, 578

Rhacophyllites, 567

Saccocaris, 655

Sculda, 660

Sowerbya, 418

Rhadinoceras, 523

Saccospongia, 52

Scurria, 442

Sowerbyceras, 567

Rhaetina, 319

Sactoceras, 527

Scutella, 237

Spanila, 367

Rhaetites, 565

Sagda, 495

Scutellina, 446

Spaniodon, 411

Rhagadinia, 49

Sageceras, 555

Suutinoblattina, 684

Sparsicavea, 263

Rhaphauocriuus, 145

Sagenites, 554

Scutus, 446

Spatagocystis, 248

Rhaphidoneina, 64

Saintia, 384

Scyllaridia, 663

Spatangus, 247

Rhectoeyma, 395

Salenia, 227

ScylLirus, 663

Spatlia, 378

Rheophax, 24

Salicornaria, 285

Scyphocrinus, 147

Spathiocaris, 658

•Bsfc^ae^itha, 477

Salicornia, 285

Scytalia, 54

Spatiopora, 269

Rhineceras, 523

Salmacis, 232

Scytalocrinus, 160

Speo, 484

Rhinidictya, 279

Salpingostoina, 445

Sebargasia, 65

Sphaenia, 421

Rhinobolus, 306

Salteraster, 207

Sedgwickia, 362

Sphacra, 409

Rhinobrissus, 247

Salterella, 490

Seebachia, 395

Sphaeractinia, 110

Rhinocaris, 657

Sandbergeroceras, 554

Selenaria, 285

Sphaerechinus, 232

Rhinoclama, 393
Rhinopora, 280

Sandbergia, 470
Sandlingites, 560

Selenella, 326
Selenopeltis, 633

Sphaerella, 410
Sphaerexochus, 635

Rhipidocardium, 369

Rhipidocrinus, 146

Sanguinolaria, 418
Sanguinolites, 361

Selenopora, 270
Seliscothon, 54

Sphaeriola, 409
Sphaerites, 209, 553

Rhipidogorgia, 106

Sannionites, 514

Sellaclymenia, 548

Sphaerium, 398

Rhipidogyra, 91

Sao, 629

Semfle, 418

Sphacrocenis, 580

Rhipidoinella, 319

Sarmaticus, 448

Semicea, 270

Sphaerocoelia, 65

Rhizangia, SO

Saxicava, 422

Semicosminium, 281

Sphaerocrinus, 158

Rhizocrinus, 169

Scaevola, 450

Semicytis, 264

Sphaeroidina, 30

Rhizophylluin, V'.»

Scala, 458

Semielea, 271

Bphaeronites, 182

Kliizopoterion, 00

Scalaria. 458

Semifasipora, 263

Sphaerucaprina, 402

Rhizostomites, 121 Scalaripora, 280

Semiiuila, 339

Sphaerulites, 404

INDKX

Sphecoptera, os4

crinu*, I is

Sueooteras, 5i i

'l'i-traiii.-r M

Spln-naulax, 57

Sin vup.v-mimi, 93

Bueosia,

Bpheniope

Stethaneura,

Sulcocava, 2ii2

Tcti-atuxis, 29

Sjiln-iiodiscu-;. 585

•. toeran, >7

Siilciima, 017

Teathopt

S/iln mini/Ill, 302

Stiboiia, 88

Simrtta, 415

Tcxtulai

Btlchopora, 285

Surciila, 4S2

Thalaiiii)]»nra. :;l. r.5

Spln-iiotn.cliiis, S3

.-", 279

Sutin-ria. ..MI

Thalassina, iioi

Sphincto/ua, 05

Sti.-topor.-lla, 27!"

Sycocera

Spllillgit.-s, 505

Sticti.trypa, 279

S//CKCI/.S/ //I-', 185

Thalassoc'-ia i,

Bphyradium,

Stigmatopygus, 240

Sycum, 47s

TliiiUiixtiiiiii", 209

Stiivchjmis, 233

Symbathocriuus, 131;

Tliainnast rai-a. 91

Bpiloblattina, os;;~

Stirpulina, :'..n

Symphyllia, ss

Tlianmisciis, 2>3

Spini-.-ra, 470

Stolic/karia, Ill

Byncyclooema, 381

Thamnograptufl, 114

Spiractin.-lla, 55

Stoinatclla. 447

Syndosmya, 418

Thaiimophylluni, 70

SpiriaH .

Stomatia, 4 17

Synhelia, 84

Thaiiuiastococlia, 05

SpiriCrr. 335

Stomatograptiis, 1 19

Synocladia, 283

Thauinatocrinus, 175

Spirifcriiia, 335

Stomatopora, 260

Synodonitites, 404

Them, 491

Spirigera,

Stomatopsis, 467

Synopella, 64

Th.-calia, 399

Spiri-civlla, 339

Stomechiuus, 230

Syntrophia, 320

Tbecidea, :J15

SpirigeH.no, 33 1

StoniopniMistcs, 232

Syriiigoceras, 521

Th.-cidflla, 310

Spiroceras. 5S4

Stortingocrimis, 130

Syringolites, 99

Tln-cidiopsis, 310

Spiroruli-x, 25<i
Spirncyathus, 92

Straiiieiituiii, 050
Straparolliua, 440

Syringopora, 101
Syringosphaeriu, 111

Tkecidium, :;15
Thecocyathus, 84

Spiroloi-nlina, 20

Btraparollus, 446

Syringostroma, 1 13

Thecocyrtella, 335

Sj.iro]M)ra, 202

Streblitcs, 509

Syringothyris, 33t;

'I'ln-cosiplionia, 49

Spirorbis, 253

Stivbluti-ypa, 281

Syrnola, 457

Tliccosiiiilia, 88

Spirostvlus, 450

St-i'cin )ccr;is .'>s^

Systroplwcems, 520

Th.-cos])ira, 340

Spirilla* 600

Strepboclad'us, osi

Tin-cost elites, 102

Spirulirostra, 600

Strephodes, 79

Taeniaster. 203

Th.-oiioa, 203

Spirulirostrina, 600

Stivpsidura, 477

Taeniodictya, 279

Thersitea, 471

Spi.sula, 420

Streptelasma, 75

Taeuiopora, 280

Tln-tidites, 558

Sponrtylobolus, 306

Streptis, 315

Tagelns, 419

Thlipsura, 045

Spondylus, 382

Strcptoceras, 531

Tainoceras, 524

Tholiasterella, 50

Spongiochiton, 435

Streptocrinus, 158

Talarocrinus, 140

Thomasina, 30S

Bpongiomorpha, 95

Streptorhynclius, 315

Tancre.lia, 407

Thoracoceras, 519

Bpongites, 290

Striatopora, 100

Tanysiphon, 417

Thracia, 390

Spongophyllum, 79

Stricklandiuia. 321

Tapes, 416

Thrincoceras, 523

Sporadoceras, 551

Strigatella, 480

Tarphyceras, 519

Thuraniiiiina, 23

Bporadopyle, 57

Strigilla, 417

Taurinia, 475

Thurniannia, 585

Sporadoscinia, 00

Strigocaris, 05 ;

Tauroceras, 376

Thylacocrinus, 146

Sportella, 411

Strigoceras, 509

Taxocrinus, 163

Thylacodes, 400

Spyridiocriuus, 145

Stringocei-halus, 327

Technocrinus, 147

Tli n*<iin><-t'i-«x, 572

Bpyroceras, 519

Strobaevx, 456

Tectura, 4)2

Thysauocrinus, 145

Squama, 050

Strobilepis, 019

Tectus, 451

Tiaracrinus, 188

Squilla, 000

Strobilospongia, 55

Teinostoina, 452

Tibetites, 560

Staeheoivras, 504

Stroboccras, 523

Teleiocrinus, 142

Tichoi/onia, 386

Starhvspoii'-cia, 54

Btromatomorpba, 95

Telescopium, 470

Tileaia, 263

Staliola, 104
Stauria, 79

Stromatoporella, 113
Stromatotrypa, 275

Tellidora, 417
Tellina, 417

Timanites, 550
Tindaria, 364

Btauroderraa, 59

Strombodes, 79

Tellinomya, 363

Tino]>onis, 31

Stauromma, 188

Strombus, 471

Tellinopsis, 302

Tirolites, 559

Stavelia, 3SO

Stromotopoj-a, 112

Teinnechinus, 232

Tissotia. 590

SU-.-misia, 397

Strongylocentrotus, 232

Tenniocheilus, 524

Titvus, (179

Stearoceras, 52:'.

Strophalosia, 317

Temnocidaris, 225

Tivela, 416

Stcganoi-i-iims, 142
Steganoporella, 287

Stroplieodonta, 313
Strophiceras, 522

Temnopleurus, 232
Temnotropris, 444

Tniaegoceras, 575
Tmetoceras, 574

.s7<-<//(>7(<,-, 24 I
St.'-iiimanniti-s, 500

Strophocheilus, 495
Stropliomena, 314

Tenarocrinus, 158
Tenea, 410

Tomocheilua, 45S, 45;)
Tonicella. 435

Stelidocrinus, 148

Strophonella, 313

Tenka, 307

Tonicia, l.;o

Stellipora, 204, 270

Strophostoma, 400

Tentaculites, 490

Tonoceras, 5S7

Btellispongia, 01

Strophostylus, 401

Terebella, 253

Torellella, 490

Stellocavra, 205-

Strotocrinus, 142

Terebelhim, 471

Tori nia, 458

Stelloria, 88

Strotopora, 270

Terebra, 481

Tiiriintt'Uii, 484

Steininatocriiiti.s, lo-_'

Struthiolaria, 471

Terebratalia, 331

Tornatellaea, 484

Stenarceste*, 505

Studeria, 241

Terebratella, 333

Tornatina, 487

StenarMirnn, 079

Stenaster, 207

Stuorella, 44.",
Stylaraea, 96

Terebratula, 329
Terebratuloidea, 324

Toriicutoceras, 586
Tornoceras. 551

Stenochirus, Oiil
Stenochisma, 323

Stylaster, 109

Slvlastraea, 87

Terebrirostra, 331
Ti-r.-dina, 424

Toucasia, 400

Stenocrinus, 152

.s7///(»..'(.s-, 78

Teredo, 424

7 'n i •*' ' '

Stenogyra, 496
Stenomplialus, 478

Stylina, 89
Styliola, 489

Teredolites, 424
Tcrqiit-iiiia, 374

Toxopneustcs, 2:;::
Trachyceras, 560

Stciioii.-ura, 083

Stylocoenia, 90

Tessarolax, 471

Trachydermon, 4:15

Stenonia, 244

Stylocora, 86

Tcstaci-lla, 490

Trach vdomia, 45S

Stenophlebia, 685

Stylocrinus, 136

Tetanocrinus, 170

Tri'i'lt it tlf I'i.tii , 4-">s

Btenopoceras, 525

Stenopora, 277

Stvlodictvon, 113
Stylohelia, 85

Tethyopsis, 41;

Tetinkc., 367

Trachyodon, 4"'i

Trachyjiora, 99

Steiiosmilia, 90
Stenotheca, 460

Stvloimrus, 070

Stylophora, s.5

Tetrachela, 661
Tetracidaris, 225

TriK-liiixny,-!,;-. .

Xti'iKitln/i-it. 404

Stephanites, 558
StephanoGeras, 580
Stephanocoenia, 90
Btephanqotinua, 1:17
Stephanophyllia, 9:;
Stepheoceras, 580

St,vlo].hyllopsis, 80
Stylophyllutn, 86
StvlotTochus, 83
Styrites, 558
Subclymenia, 523
Subemarginula, 446
Subulites, 457

Tetracrinus, 170
Tetractinella, 339
Tetradella, 644
Tetragom'tes, 569
Tetragonoceras, 525
Tetragraptus, 118
Tft rii me res, 531

Tragophyllooeraa, 5i;s

Trapcximn, 395
Tivmabolites, 61
Tremadictyon, 57

Ti-i'iiinti'lla, 277
Tn-iiiatis, 309
Trcmatiibnlus. 309

VOL. I

2 z

706

TEXT -BOOK OF PALAEONTOLOGY

TiTnu/fon'i'Ks, 523 Tropidocaris, 050
Tremitoilixi-iis, 523 Tropic! oceras, 57s

Uronectcs, t;59
Ussuria, 50r>

Volv.ila, -J.S7

''" -4s~

Trematonotus, 445 Tropidoleptus, 330

Trematopora, 275 Tropidomya, 393

Ussurites, 5i;o
Uvanilla. 44S

Volvulina, 4s:,

Treniatospira, 337

Tropidopora, 281

Uvigerina, 28

Vulsellina, 872

Tresus, 420

Tropites, 554

Tretoceras, 52* '
Tretospira, 458
Triacrinus, 130
Triaena, 688

Truncaria, 470
Truncatula, 204
Truncatulina, 30
Tryblidiuni, 442

Vaginella, 490
Vaginoeeras, 514

I'lii/liio/wra, 289
Vaginulina, 27

Waagenia, 445, 57,s, 583
Waagenoceras, :<r,i
Waehneroceras. 57.1
Wakullina 3s4

Triauioceras, 554 Tubina, 401
Triartbrus, 029 i Tubipora, 107

Valenciennesia, 492
Valletta, 401

U'/ililiit'iniiti, 333
Waltonia, 333

Triboloceras, 523 Tudicla, 477

Valvata, 463

AVartbia 445

Trichasteropsis, 208 Tudora, 400

Valvatina, 4S9

Welsehia, 570

Trn-hil,:*, 309
Tricoelocrinus, l£a
Tritons, 409
Trigfria, 326, 337

Tugonia, 421

Tnloloma, 463
Turbina, 450
Turbinaria, 95

Valvulina, 28
Vanuxemia, 305
Vascoceras,-586
Vasseuria, 598

Whiteavesia, 385
Whitella, 365
n'l,;tjir<l<]<-H(i, 338

Trigonella, 332 Turbinella, 479
Trigonia, 379 Turbinilopsis, 459
Trigonoceras, 523 Turbinolia, 83

Velates, 454
Velorita, 397
Veloritina, 397

Willemoesia, 001
Williamia, 493
\Vilsonia. 324

Tfii/iinoi-nnlia, 365 Turbo, 448

Venericardia, 398

Witchellia, 57s

Trigonodictya, 280 Turbonellina, 450

Venempis, 410

Woodia, 395

Trigonodus, 375
Trigonosemus, 332

Turbonilla. 457
Turbonitella, 459

Veniella, 395
Venilia, 395

Woodocrinus, 100
Wortbenia, 443

Triifonntn'tn, 335
Trigonr.lina, 392
Trimerella, 300

Turnus, 424
Turonia, 49
Turricula, 479

Venilicardia, 395
Ventriculites, 00, f.5
Venus, 415

Worthenopora, 283
Wyomingites, 556

Trimeres, 531

Turrilepas, 649

Vennetus, 406

Xantbo, dOii

Trimerocephalus, 636

Turrilites, 587

Vermiceras, 575

Xanthopsis, tiOr,

Triineroceras, 531
Trimorion, 531

Turritella, 465
Turtonia, 41 1

Verneuilia, 330
Verneuilina, 28

Xenaspis, 556
Xenaster, 208

Trinacria, 305

Tyleria, 390

Verruca, 651

Xenocidaris, 220

Trinucleus, 025

Tylopoina, 403

Verrucocoelia, 57

Xenocrinus, 145

Trioculina, 20

Tympanotomus. 470

Verruculina, 53

Xenodiscus, 556

Triodonta, 397

Typbis, 477, 008

Vertagus, 409

Xenoneura, 684

Triplecia, 315

Vertebral ina, 27

Xenopbora, 463

Tripleuroceroceras, 529

Udora, 061

Verticordia, 392

Xipbidiocaris, 055

Ti-ipJi:i-, 477

Udorella, 661

Vertigo, 490

Xipboteutbis, 596

Trploca, 484

Uintacrinus, 165

Vertumnia, 370

Xylobius, 081

Tripneustes. 233

Ulangia, SO

Vesttnautilus, 523

Xylotrya, 424

Triptera, 490

Ulocrinus, 102

Veroda, 301

Tri])ylus, 245

Uinbonium, 451

Vibracella, 286

Yi'txx, 480

Triton, 474

Umbraculum, 487

Vicarya, 409

Yoldia, 364

TritoniiJen, 475

Umbretta, 487

Vincularia, 28ii

Tritonium, 474

Uncinella, 335

Virgatites, 583

Zaphrentis, 75

Trivia, 473

J 'iirin nil IIH, 324

Virgularia, 106

Zdimir, 321

Trochalia, 408

Unciuulus, 324

Vishnuites. 550

Zeacrinus, 100

Trocbaimuina, 23

Uncites, 335

Vitrina, 497

Zeilleria, 332

Trochoceras, 524

Umlularia, 450

Vitrinella, 452

Zellania, 330

Trochocvatbus, 84

Unqula, 306

Vitulina, 338

Zeniira, 470

Trocbocystites, 180

Ungulina, 410

Viviparus, 403

Zenatia, 420

Trochoiitrs. 519

UnguKtes, 306

Vlasta, 301

Zeuglopleurus, 232

Trocholitoceras, 519

Unicardium, 407

Vola, 380

Zittelia, 472

Trocboinorpha, 497

Unicytis, 204

Volbortbella, 510

Zittelispongia, 01

Trocbonema, 449

Unio, 377

Volborthia, 308, 312

Zitteloceras, 522

Trochoseris, 91

Uniocardiuin, 413

Voluta, 480

Ziziphiniix, 451

Trocbosinilia, 88

I 'it i mid 375

Volutella, 480

Zonites, 497

Trochotoma, 444

Unitrypa, 282

Volutifusus, 480

Zonoporn, 200

Trocbus, 450

Uphantaenia, 55

Volutilithes, 480

Zonozoc, 050

Troostocrinus, 195

Uptonia, 574

Volutoderma, 480

Zugmeyeria, 329

Tropaeum, 571

Uranoceras, 527

Volutomitra, 480

Zurcberia, 577

Trophon, 477

rntxtrreUfi. 207

Folutomorpha, 480

Zygites, 443

Tropiceltites, 558 Urda, 668

Volvaria, 485

Zygopleura, 456

Tropidaster, 210 ' Urechinus, 244

Volviceramns, 370

Zygospira, 333

END OF VOL. I.

Printed by R. & R. CLARK, LIMITED, Edinburgh,

[it

UH H !