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GEOLOGICAL SURVEY OF CANADA.

SIR W. E. LOGAN, F.RS., DIRECTOR.

FIGURES AND DESCRIPTIONS

OF

CANADIAN ORGANIC REMAINS.

DECADE III.

ORES

Montreal :
PRINTED BY JOHN LOVELL, ST. NICHOLAS STREET.

1858.
e

CONTENTS.

PAGE.
I.—Preracez, by Sir W. E. Loaan, F.R.S., Director of the Geological
SMa, O COME csicqscgoansdco0baDade wis a wishaeiatrs -yerelenorsets 5
II.—On the Cystipzm of the Lower Silurian Rocks of Canada. By
E. Briuuines, Esq., F.G.S. . 1 vacut. PNM ct Miascvercrs er etehs, cern eciere 9
III.—On the Asteriap# of the Lower Silurian Rocks of Canada. By
E. Burnes, Esq. .-. SE aA ec eG RUDE aL 75

IV.—On Cyctocystowss, a new genus of Echinodermata from the Lower
and Middle Silurian Rocks. By J. W. Saurmr, Esq., F.G.S., of
the Geological Survey of Great Britain, and H. Baines, Hsq.. 86

}

%,

V.—On the Paleozoic Bivalve Entomostraca of Canada. By T. R.

Toni Hage) BGG: a femeie wa vac cide ce aisiersisches a sae! delete - 91

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PREFACH.

OnE of the subjects comprehended in the recommendation of the
Select Committee appointed by the House of Assembly, on the
Geological Survey, in 1854, was the publication of figures and
descriptions illustrative of such new organic forms as might be
obtained in the progress of the investigation. In compliance with
this recommendation, it was determined that the publication should
be made in parts or decades, after the mode adopted by the
Geological Survey of the United Kingdom, each part to consist
of about .ten plates, with appropriate descriptive text, and to
comprehend one or more genera or groups of allied fossils, or the
description of several species, for the illustration of some special
point in geology.

The first part or decade was confided for description, in 1855, to
Mr. J. W. Salter, one of the Paleontologists of the Geological
Survey of the United Kingdom. This comprehends different genera
and species from one locality. Of these, several are new, while
thers are more perfect forms of species already partially described ;
and the general object is to exhibit a commingling of forms here-
tofore supposed to belong to distinct epochs. The plates of this
decade are the work of Mr. W. Sowerby, from drawings by
Mr. R. C. Bone. The engravings are on steel; nine of the plates
are finished, and it is expected the tenth will be completed in a
short time.

The second decade was undertaken also in 1855, by Mr. James
Hall of Albany, so justly celebrated for his works on the Palzon-
tology of New York. It will comprehend the description of a.
large number of remarkable new forms of Graptolithus and allied
-genera from the Hudson River group. The drawings are by

vie PREFACE.
Mr. F. B. Meek. Six plates have been engraved on steel by
Mr. J. E. Gavit, and ten more plates are in the engraver’s hands.
The number of species will probably be twenty-four, of which
Mr. Hall has already given a description in the Report of Progress
for the year 1857.

On the appointment of Mr. E. Billings as Paleeontologist of the
Survey, in 1856, his first duty was to effect an arrangement of the
Museum. This being accomplished, he devoted his attention to a
third decade. This comprehends all the Cystideze and Star-fishes,
as well as all the Entomostraca, of the collection. With the view
of obtaining the plates necessary for the illustration of these, Mr.
Billings, in the month of February last, carried his fossils to London.
Finding that considerable delay was likely to attend the publication
of the decade should he illustrate it by engravings on steel, he
determined to have recourse to lithography. Although minute
detail cannot be so finely given by this mode, nor so large an
edition be obtained, it is yet perfectly suitable for all practical
purposes. It is occasionally used for the fossils of the British
Survey, and very generally for the illustration of the best paleon-
tological works on the continent of Europe. The twelve plates
which illustrate the third decade are the work of several well-known
artists, who have all their respective merits. One of the plates is
by Mr. R. C. Bone, two of them by Mr. J. Dinkle, four by Mr.
Tuffen West, three by Mr. H. S. Smith, one by Mr. W. Sowerby,
and one by Mr. G. West. Of the descriptive part, the Cystidee
and Star-fishes are by Mr. E. Billings; the genus Cyclocystoides by
Mr. Salter and Mr. Billings; and the Entomostraca by Mr. T. R.
Jones, assistant-secretary of the Geological Society of London, who
is considered the best authority on this particular family of animals,
and had previously described a large number of the Canadian species.

While Mr. Billings was attending to the progress of his decade
in London, it appeared doubtful which of the three that were in
hand would be first ready for publication. He, in consequence,
caused to be registered on the plates, as the number of the decade,
the figure which indicates the order in which it was commenced.

PREFACE. vii.

It therefore appears as the third decade, but being the first ready,
and the subject quite distinct from those of the other two, no
hesitation is experienced in placing it first before the public.

Mr. H. 8. Smith, who, as already stated, supplied three of the
plates, has been induced to come out to Canada with the design of
devoting his attention to the representation of the fossils of the
Provincial collection; and it will therefore in future be unnecessary
to go out of the country for the illustration of them, unless it be to
procure the aid of the best authority on some special subject.

Of the third decade an edition of 2000 copies is issued. Of these
500 copies are reserved for the members of the Legislature; and
it is intended to fix upon the remainder a moderate price, and
dispose of them to the public through some respectable bookseller.
By this means it is hoped that they will fall into the hands of those
who will really appreciate them. The same course will be pursued
in respect to the first and second decades, when they are ready.

A fourth decade is now in hand which will illustrate the Crinoids
of the collection.

W. E. LOGAN.

Montreal, 30th June, 1858.

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CANADIAN ORGANIC REMAINS.

On the CystTiDE® of the Lower Silurian Rocks of Canada. By
E. Bruuines, F.G.S.

SECTION I.
GEOLOGICAL POSITION, STRUCTURE AND CLASSIFICATION.
I. Introductory Observations.

As several elaborate and beautifully illustrated memoirs upon the
structure and affinities of the Cystidez have appeared during the
last few years, it would be superfluous, on the present occasion,
to enter upon a re-examination of the subject, were this decade
designed to circulate only among scientific men, for whom it would
be sufficient to give nothing more than the most concise technical
descriptions of the species. But being intended also for the use
of the students of Canadian geology—whose number is rapidly
increasing throughout the Province—it appears necessary to com-
mence with a general summary of what has been ascertained up
to the present time concerning the zoological characters and distri-
bution in time and space of this somewhat extraordinary group of
extinct organisms. By this course it is hoped that, while the
foreign geologist will receive all the intimation he desires of what
we are doing, the growth of science in our own country will also
be promoted.

The Cystideee were a race of small marine animals, which
flourished vigorously during the Silurian period, but totally disap-
peared before the commencement of the Carboniferous era. They
were closely allied to that interesting family, the lily encrinites,
or Crinoids, and, like them, entirely covered, as with a coat of mail,
by a dermal or external skeleton of thin calcareous plates, which
were sometimes richly ornamented with radiating ridges or striz.
Attached to the lower extremity of the body was a short flexible
stalk, usually called the column, that served to anchor the animal

10 STRUCTURE OF THE CYSTIDEA.

securely to one spot on‘the bottom of the ocean throughout life;
and at the opposite, or upper end, a set of arms, which, in addition
to their other functions, may have assisted in the collection of food
by exciting currents of water towards the mouth. This latter
organ was a circular or oval aperture, situated in the side, below
or near the summit, and in some species must have been also the
passage through which such matter as could not be digested was
thrown out. The young were developed from eggs, which were,
there is good reason to believe, generated in the grooves of the
arms or pinnulz, where, as has been ascertained by actual observa-
tion, the organs of reproduction are situated in the Crinoids that
exist in some of the seas of the present time.

Concerning the food, habits, or other particulars of the natural
history of the Cystidez, we can never hope to acquire any great
amount of information, as the race wholly perished many ages ago,
and the only evidences we have of its existence are, with few
exceptions, very imperfect skeletons, which exhibit nothing except
the structure of the external hard parts. It is only probable that
their nourishment was derived from minute particles of animal or
vegetable matter diffused through the waters in which they lived.
The structure and position of the mouth are such, that they could
not have been highly carnivorous, while their nearly sedentary
condition would altogether preclude the capture of any prey except
such as might float by chance within their reach. Animals rooted
to the ground like a piant would fare ill were they organized to
support life by the predacious mode only.

The fossil remains of the Cystidez consist for the greater part of
mere fragments of the plates and columns; but these, in certain
localities, occur in such prodigious abundance, that they constitute
the principal portion of strata of rock several feet in thickness.
Of many of the species specimens of the bodies are exceedingly
rare, and when these are discovered they are usually more or less
crushed and distorted. While the fossil Corals, Brachiopods and
Gasteropods may be collected in hundreds, few cabinets can boast
of half-a-dozen good Cystideans, even in those countries where
whole formations of rock are composed of the exuvie of the race.

With respect to their distribution in time, they have been dis-
covered in Bohemia, by M. Barrande, in beds which lie in the very
bottom of the oldest rocks containing traces of animal life; and
therefore, according to the present state of our knowledge of the
primeval fauna, they were among the first living things that made

STRUCTURE OF THE CYSTIDE. 11

their appearance upon the surface of this planet. The Lower
Silurian formation, in the several countries where it has been most
studied, has at its base a great thickness of stratified rocks which
are altogether without fossils—at least none have been discovered
in them up to the present time. ‘Then follows in conformable
succession a series in which organic remains do occur, but not m
any great abundance. This is the lower half of the fossiliferous
portion of the Lower Silurian. In Great Britain these strata are
the Lingula Flags of Sir Roderick Murchison; in Bohemia the
Primordial Zone of Barrande ; and in Norway and Sweden the
Alum Slates, or Regions A and B, of M. Angelin, the leading
paleontologist of that country. In America they have not been
distinctly recognized, although it is doubtfully anticipated that the
Potsdam sandstone and the lowest sandstones of the western states
may be of the same age. It is more probable that some of the
ancient schists in the eastern states, where a large trilobite of the
genus Paradoxides has been found, are of the age of this ‘‘ primordial
zone of life.’ In whatever way this point may be decided
hereafter, it is only in Bohemia that Cystideze have been found so
low down in the geological series. Four species have there been
discovered, together with twenty-seven species of Trilobites, one
Brachiopod ( Orthis Romingeri, Barrande), and one Pteropod ( Pugi-
unculus primus, Barrande), but no Crinoids.

In Scandinavia the Primordial Zone has not yet yielded traces
of either Crinoids or Cystidez, but seventy-one species of trilobites,
and eight Brachiopods of the genera Lingula, Orbicula, Orthis and
Atrypa, have been discovered, with one or two graptolites and a
small orthoceratite, near the top.*

In England the Lingula Flags, which are regarded as the
equivalents of the Bohemian and Scandinavian deposits, have
furnished a very similar fauna of trilobites and rare mollusca, with
one or two graptolites; but up to this date only a fragment of a
-crmoidal column and no Cystideans. It is also to be observed,
that in none of these countries have any corals been detected in
these lowest fossiliferous strata.

In the upper half of the Lower Silurian, organic remains become
exceedingly abundant, and it is in this part of the geological series
that the Cystidez attain their greatest development, both in the
numbers of the species and of the individuals. This deposit is

.

* Parallele entre les Dépots Siluriens de Bohéme et de Scandinavie; par M. Barrande
page 39 et seq.

‘

12 STRUCTURE OF THE CYSTIDEA.

represented in England by the Llandeilo and Bala or Caradoc
groups of Murchison; in Bohemia by the stage D, containing the
“second fauna”? of Barrande; in Scandinavia and Russia by the
‘Regions BC, C and D of Angelin, and the “ Pleta” or Orthoceratite
limestone; and in Canada by all the groups from the base of the
Calciferous Sandrock up to the top of the Hudson River group.

While these rocks were slowly being deposited, the Cystideae
literally covered the bottom of the ocean in dense swarms in certain
localities which were favorable to their existence, one generation
growing upon the remains of another, until thick beds were formed.
In Russia, Norway and Sweden, Sir Roderick Murchison* discovered
them in the Pleta limestone, which appears to be of the age of the
Chazy, Birdseye, Black River and Trenton limestones, packed together
like ‘bunches of enormous grapes ;” and in Bohemia M. Barrande
has found them equally abundant. He says that the Crinoids and
Star-fishes have left only insignificant traces, but the Cystideze form
entire beds of from one to two yards in thickness.t

In Canada they make their appearance rarely in the Calcifterous
Sandrock, but in the Chazy and Trenton their remains are more
common, consisting however mostly of the detached plates packed
together in thick strata. They are not very generally distributed,
but confined: to certain localities. Throughout extensive regions
occupied by these formations scarcely a vestige of a Cystidean is to”
be found; but in other places, such as the neighbourhoods of the
cities of Montreal and Ottawa, they are exceedingly ple
Everywhere however good specimens are rare.

M. Barrande, in comparing the European rocks of this age,
observes, that in Bohemia the Cystidean zone occurs about the
centre of his stage of Quartzites D, which would be also the
equivalent of Angelin’s group C. In England the corresponding
level would be about the Bala limestone, where the principal masses
of Cystideee are found. The abundance of their remains in the
Chazy and Trenton of Canada confirms the views of M. Barrande,
and at the same time tends to shew that these two American
formations should be paralleled with the Bala rather than with the
Llandeilo. This question however cannot be decided without
more perfect lists of fossils than can be at present procured.

The number of species of Cystidez that occur in this zone are as
follows, so far as I can ascertain, in these countries respectively :—

* Geology of Russia and the Ural Mountains; by Sir R. I. Murchison, page 38.
+ Systéme Silurien du centre de la Bohéme; par M. Joachim Barrande, page 66.

STRUCTURE OF THE CYSTIDEA. 13

Sena AE ANG IRWEEAS poggeeoucoce se dueeeo enue on 20
Greate Brit aimppereccnssypsreretereise eis Asi accceleyetcia leas aps igen chats 13
ONGVINE, AIO sodos cacinde eed oolICdeoUboboromoUodT 8
(CV REIG IE bie aid Pectin a Bee aire i re eae NS A Sean Lie 21
SING Wat 6 OIG napey sia cystine: ayrareiscpene et eu eMeponeliauene sum mneea maa tig Geet Il

63

In consequence of the imperfection of the specimens and some
confusion in the descriptions of different authors, the above numbers
may not be exactly correct; but from what I have seen it appears
to me that there are more than sixty species, described and unde-
scribed, belonging to this period.

In the Upper Silurian there are in Great Britain nine species,
and in Canada and New York about the same number, but none in
either Bohemia or Scandinavia have yet been made public.

According to the present state of our knowledge, then, in the
lower half of the Lower Silurian there are four species, in the
upper half sixty-three, and in the Upper Silurian eighteen.

Very little dependance however can be placed upon numerical
comparisons, such as the above, in dealing with questions relating
to the Cystidez or Crinoidez, for the reason that new discoveries
are every year being made which very materially change the aspect
of these computations. For instance, six years ago only eleven
Crinoids, one Cystidean, and one Star-fish, were known in the
Lower Silurian of New York and Canada, but in the collection of
the Geological Survey of Canada there are now twenty-one species
of Cystideans, about fifty Crinoids, and ten Star-fishes, or in all
eighty-one species of Echinodermata from this formation instead of
thirteen. }

In: the Devonian formation several forms resembling Cystidez
have been referred to that group of organisms; but it remains still
to be shewn that they are true Cystideans. The weight of the
evidence tends to shew that the race was ushered in with the first
living inhabitants of the deep—attained its greatest development
in the latter portion of the Lower Silurian era, and died out about
the time of the commencement of the Devonian. Of its associates
in the Primordial Zone, the Brachiopoda, Pteropoda and Bryozoa
remain to the present day. The trilobites held their possession of

* Bronn’s Index Palzontologicus. Zweite Abtheilung, p. 181.
+ On the British Cystidee, by Prof. E. Forbes. Memoirs of the Geological Survey
of Great Britain, vol. ii. part 2, p. 483 et seq.

14 STRUCTURE OF THE CYSTIDE.

existence until the Carboniferous period, and the graptolites disap-
veared early in the Upper Silurian. With the exception then of
the graptolites, the Cystidee were the first race that became extinct.

Il. The General Form and External Skeleton of the Cystidee.

In form the Cystidez were either globular, oval, pyriform, conical,
or sub-cylindrical, and their dimensions seldom more than one inch
and a-half or two inches in length and breadth. They were protected
by an external skeleton ee of flat polygonal calcareous plates,
which were so accurately fitted together that they enclosed, with the
exception of the arms and column, the whole of the animal almost as
completely as an egg is contained in its shell. In some of the species
the plates were neither limited as to their number, nor arranged
according to any definite order, and in these, as the bedy increased
in size, the corresponding enlargement of the skeleton was effected
both by the growth of the older plates and the introduction of new
ones between them. In many species the number of the plates
and plan of arrangement remained constant throughout the life of
the animal, the shell being enlarged by the continual growth of
the origina! pilates and without the addition of new ones. In others,
such as the species of the genus Pleurocystites, both of these modes of
increase prevailed, the dorsal side having the number and arrangement
definite and the ventral indefinite. The growth of the individual
plates appears to have been by the assimilation of fresh particles of
matter throughout the whole mass, instead of by additions to the edges.

Ill. The Mouth, Ambulacral Orifice and Anus.

In the Cystideze we find two and in some species three principal
apertures through which the more important fopetions of the animal
economy were exercised. These are :—

1. The mouth,—A large orifice situated on one side, usually about
the middle of the body, but sometimes near either the base or the
apex. In many species it was provided with a valvular apparatus,
by which it was opened or closed; in others no such provision
existed, or at least it has not been preserved in the fossil state,
It is quite probable that in most of the species this orifice subserved
the double function of a buccal and an anal aperture.

2. The ambulacral orifice.—This opening is always situated in or
near the centre of the upper part of the body, and in the central

STRUCTURE OF THE CYSTIDEA. 15

point between the bases of the arms when these are present.
Through it tne vessels of the aquiferous system and of the organs
of reproduction, which were situated in the grooves of the arms,
communicated with the interior. There can be little doubt also
that the nervous filaments, if the Cystideze possessed any, gained
access to the arms through this passage.

Concerning the functions of these two apertures much difference
of opinion has existed amougst the best naturalists, some regarding
the large opening in the side as an ovarian orifice, others believing
it to be the mouth. Since the discovery recently made of the
ambulacral orifices of the true Crinoidez and also of the arms of the
Cystidez, it appears to be quite certain that the latter opinion is
the correct one. I shall notice this subject more at length in the
next section.

3. The anus.—In some species there is a third small aperture,
which is always situated near the apex. It is usually minute and in
certain genera has not yet been observed. This orifice is designated
the anus by most authors, a view of its characters somewhat sup-
ported by the fact that we know of no other function that can be
assigned to it. In the species which were not provided with this
opening, the excrements were ejected through the mouth, as in
those Star-fishes that have no anus.

IV. The Arms, Ambulacral Grooves and Pinnule.

The arms of the Cystidez only differ from those of the true
Crinoidez in the position which their bases occupy in the skeleton,
and in the general inferiority of their development. The structure
of the arms is essentially the same in the two groups, but in none
of the Cystidez do we find them of a very high degree of perfection.
I propose to arrange them in the following order :—

1. Cystideze in which the body of the arm was not developed, but
only the grooves and pinnule. The following species are examples:

Cryptocrinus cerasus (von Buch), which in the specimens I have
observed, has fourteen small plates arranged in a circle around
the ambulacral orifice. Each one of these exhibits upon its surface
a small irregular scar, which marks the position of the attachment.
of a single pinnula. No grooves are visible, but it is quite evident
that this species had no true arms.

In Echino-encrinites angulosus (Pander), there were five or six
pinnule, with their corresponding grooves.

16 STRUCTURE OF THE CYSTIDEA.

In the genus Glyptospherites (Miller), represented by the species
Spheronites Leuchtenbergu (Volborth), very slightly impressed grooves
radiate from the ambulacral orifice and ramify over the surface of
the body. At the end of each branch the place of the attachment of
a pinnula is seen. Upon the closest examination of good specimens
I have been unable to detect any indication that these grooves were
occupied by an arm that was bent backward upon the body as in the
genera Apiocystites (Forbes), and Callocystites (Hall). It is also quite
clear that the pinnule were not seated upon arms of this kind, but
immediately upon the surface of the plate. The grooves are not
excavated but impressed ; they appear as if they had been formed by
several fine threads lying on the surface, while the plates were too
soft to sustain their weight. In this species the pinnulze were distant
from each other and scattered over the greater part of the body. In
C. cerasus they formed a circle around and quite close to the orifice,
and in E. angulosus they were also confined to the apex, but some-
what scattered. According to my views we have in these forms the
lowest and most rudimentary condition of the radii yet seen in any
Crinoideze or Cystidee. The ambulacral vessels issued from the
interior through the orifice, and having nothing to support them,
crept along the surface, sending out branches to those points where
the pinnule arose. The main trunk of the arm, or that which
bears the pinnulz in the Crinoids, was totally absent: it was never
developed. There is nothing but the grooves and the pinnulz to
indicate the existence of an ambulacral system.

2. Cystideze in which the arms were developed, but bent back-
ward and attached to the body. In these we perceive a structure
one stage more perfect than in the several species just noticed. The
arms of Apiocystites pentrematoides (Forbes), Callocystites Jewettvi (Hall),
and Glyplocystites multiporus, are all constructed upon the same type.
They originate in the apex of the fossil, where their bases are all
crowded together into a narrow space, in the centre of which is the
ambulacral orifice. They are composed of double series of flat plates
which alternate with each other, and have the usual grooves of the
Crinoids along their centres. On each side of the groove is a row of
pinnule. From the main groove smaller ones branch out to the
base of each pinnula. The whole structure is exactly that of the
arms of the true Crinoidez, but not so perfectly developed. The
arms of all the Crinoids have sufficient strength to stand erect, but in
these Cystidez it appears to have been otherwise, and consequently,
we find them not free and supporting themselves, but lying at full

\
STRUCTURE OF THE CYSTIDEA. aba

length upon the surface of the body. In Amygdalocystites florealis
and the two species *of Malocystites, the arms are also recumbent,
but their position is somewhat different. The grooves are not in
the centre of the upper surface of the arms, but upon one side, and
there is but one row of pinnule. These characters are not the
results of a different structure, but are occasioned by the curious
position of the arms, which do not rest with their backs in contact
with the surface, but with one of their sides undermost.

3. Cystidee with free arms—The only species known is Comaro-
cystites punctatus (Billings), which has not only the free arms but also
the pinnulz of a true Crinoid. It is probable that some of the small
Cystideans described by Professor Forbes, in the ‘‘ Memoirs of the
Geological Survey of Great Britain,” belong to this group. . The four
little prominences on the top of Caryocystites munitus appear to be the
remains of arms which were free, and of a large size in proportion
to the magnitude of the body. The genus Pleurocystites has two
appendages which are more of the nature of pinnule than arms.
They are composed of a double series of joints, and have the grooves
bordered by small marginal plates. In this respect they exactly
resemble the pinnulz of Pentacrinus caput-Meduse as figured by Miller.
Although in the descriptions of the species I have called them arms,
I am not at all satisfied that they are entitled to be so designated.

The distribution of the arms of the Cystideze above given into
three kinds, is not intended as a classification of the species into
groups. On the contrary, we find that widely different genera, such
as Malocystites and Apiocystites, have recumbent arms, and others
equally far apart, such as Echino-encrinites and Glyptospherites, with
pinnulee only, while Comarocystites, which agrees with the Spheronites
in the numerous plates’ of the body, has the arms free. Even in
the same genus we have two of those degrees of development, for
Glyptocystites Logani has only pinnule, but G. multiporus has both
recumbent arms and pinnule. It is quite clear therefore that such
characters are not often of more than mere specific importance in
classification.

V. The Calycine Pores or Pectinated Rhombs.

Many of the Cystidez were also provided with a peculiar system, .
consisting of pores which penetrated through the plates of the body,
and probably served as media of communication between the interior
and exterior, although the precise nature of their functions has not

B.

18 STRUCTURE OF THE CYSTIDEA.

yet been ascertained. The form and distribution of these pores
vary greatly, but certain groups of species, closely related by other
characters, have them arranged after a plan common to themselves,
and not found in the species of other groups. Thus the genera
Prunocystites (Forbes), Pseudocrinites (Forbes), Apiocystites (Forbes), |
and Lepadocrinites (Conrad), belong to a group characterized by a
skeleton composed of a small number of plates, about twenty, which
are arranged in four series. All these have three pectinated rhombs,
one situated at the base and two near the apex. Echino-encrinites
(Meyer) and Glyptocystites have the same number of plates, but
the rhombs, although the same in general structure, are arranged
in a manner somewhat different from the others: Echino-encrinites
having two rhombs at the base and one in the upper part of the
body, while Glyptocystites has from ten to thirteen rhombs ; but two
of these, in G. multiporus and also G. Forbesi, are situated at the
base of the dorsal side, in a position exactly like that of the two
basal rhombs of Echino-encrinites. In those genera with the skeleton
composed of an indefinite number of plates, the pores are circular,
and not clefts of considerable length, as in the others. It appears
therefore that good characters for classifying the species of the
Cystideze into groups can be derived from the form and arrangement
of these organs, and accordingly a classification upon this principle
has been proposed by Professor J. Miller of Berlin. The outlines
of his system will be given hereafter.

VI. The Column.

The stem, stalk or column of the Cystidez is usually short and
tapering from the body downwards. In other respects it is the same
in structure as the columns of the ordinary Crinoideze. The most
remarkable form is the column of Lepadocrinites gebhardui (Conrad),
from the Lower Helderberg rocks of the United States. It differs
from all others known in having a large portion of the lower
extremity composed of a single long spindle-shaped joint.

SECTION II.

ON THE AMBULACRAL ORIFICES OF THE CYSTIDEH AND CRINOIDEA.

If it were possible to procure a Cystidean with all the internal
and external organs perfectly preserved, it might be easy to deter-

STRUCTURE OF THE CYSTIDE. 19

mine accurately the functions of the several orifices that have
occasioned so much discussion among the eminent naturalists and
paleontologists who have written upon the structure and affinities
of these fossils. It is not however probable that a single specimen
retaining even a vestige of the soft parts will ever be discovered.
and we are compelled therefore to content ourselves with the next
best method of conducting the investigation. The only course is
to proceed by examining and comparing the offices of the ambulacral
grooves and apertures of some of the existing species of Echinoder-
mata which have been dissected by observers of good authority.
In pursuance of this plan, I shall here notice briefly such points in
the organization of the Star-fishes and recent Crinoids, as appear to
have a direct bearing upon the subject.

I. Ambulacra of the Star-fishes.

The Star-fishes are not closely related to either the Crinoidea or
the Cystidez in the structure of their skeletons, but they present
the most perfect examples of Echinoderms with all the ambulacral
vessels located in grooves upon the outside. The mouth is situated
in the centre of the under-side of the body, and the ambulacra
consist of a set of deep furrows which radiate therefrom to the outer
extremities of the rays. They contain the following organs, all of
which communicate with the interior by passing inward through
the mouth.

Ist. The aquiferous canals, consisting of a set of long tubular
vessels extending the whole length of the furrows and entering the
mouth. They are attached to, or originate in, another vessel, which
forms a ring around the mouth, inside of the body. Connected with
these vessels, and situated in the grooves, are two or four rows of
suctorial feet, the whole constituting the most extraordinary system
of locomotion known.

2d. The nerves of the ambulacra. These are also connected with a
ring around the cesophagus, and pass out from the interior through
the mouth. The main trunks lie along the bottoms of the ambula-
cral grooves, and send out branches to the suctorial feet.

3d. The blood-vessels, which also proceed from circular canals in
the interior, and reach the ambulacra through the mouth.

The aquiferous canals and suctorial feet, with their nerves and
blood-vessels, constitute the ambulacral system of the Star-fishes ;
and as all the organs are situated on the outside of the animal, and

20 STRUCTURE OF THE CYSTIDE.

communicate with the interior through the mouth, one of the
functions of the aperture is that of an ambulacral orifice. In those
species without an anus, the ova and excrements are extruded
through the oral opening. In many which have an anus there are
several sets of genital pores for the production of the eggs.

The following then are the apertures which in the Star-fish with-
out an anus are all combined in one :—

1. The mouth. 3. The ovarian apertures.
2. The anus. 4. The ambulacral orifice.

In those with an anus and genital pores, the mouth has of course
but two functions.

II. Recent Crinoids.

In the recent species of Crinoids, such as Pentacrinus caput-Meduse,
and the several species of the genus Comatula, the ambulacral
grooves radiate from the mouth and are continued along the ventral
sides of the arms to their extremities. At first there are five only,
but these divide into ten before reaching the margin, in order to
furnish a groove for each of the ten arms (see fig. 1). The grooves
also send off slender branches to the pinnule, and they are all
provided with suctorial feet, ambulacral canals, nerves and blood-
vessels, as in the Star-fishes. The young however do not escape
through the mouth, but the ova are developed beneath the soft skin
in the grooves on the ventral side of the pinnulee, and when the
proper time arrives are set free. The vessels of the arms all enter
turough the mouth, and as there is always a distinct anus, it follows
that this aperture has two functions.

1st. It is the mouth.

2d. It is the ambulacral orifice.

3d. It must also, to some extent, be regarded as an ovarian
aperture, because in all animals there must exist a connection of
some kind between the reproductive and nutritive systems. It has
been demonstrated by Mr. J. V. Thompson of Cork (see Edinburgh
New Philosophical Journal, 1836), that the ova, as above mentioned,
are generated in the arms and pinnule outside of the body; and
as there is no other aperture for that purpose, then it must follow
that whatever may be the vessels by which a communication is
effected between the ovaries and the interior, they can only pass
through the mouth. For the same reason, the ambulacral orifices

STRUCTURE OF THE CYSTIDEA. 21

of the paleozoic Crinoids (to be mentioned in the next paragraph)
partake also of the nature of ovarian or genital apertures.

The structure of the Star-fishes and recent Crinoids only agrees in
these respects: that both groups have the ambulacra outside of the
body, and the ambulaeral orifice and mouth combined in a single
opening.

Ill. The Paleozoic Crinoids.

In at least a great many species of the palzozoic Crinoids we
find an arrangement so different, that it almost justifies their
separation into a division distinct from the recent forms. The
structure of the arms is precisely the same, and there is not the
least doubt that their functions were also to support the ambulacra
and reproductive organs, as in Pentacrinus and Comatula. In the
ventral surface however, or in the circular space surrounded by
the arms, there is only one large opening, but no grooves radiating
from it to those of the arms. To shew more clearly the difference
between the recent and extinct species in this respect, I have
constructed the following diagrams :—

Fig. 1. Recent Crinoid. Fig. 2. Paleozoic Crinoid.

Figure 1 is a diagram of the ventral surface of a recent Crinoid
with the mouth, m, situated in the centre, and the ambulacral
grooves radiating from it to the arms. The anus, a, is situated
between the centre and the margin, and in some of the species of
the genus Comatula it forms a tubular projection of several lines in
length.

Figure 2 is an ideal representation of the ventral region of a
paleeozoic Crinoid, with only one opening, m a, but with no grooves
leading from it to the arms.

bo
bo

STRUCTURE OF THE CYSTIDEA.

All paleontologists are agreed that this single aperture, found
in all the ancient Crinoidee, is both the mouth and the anus.
It is sometimes situated in the centre, equidistant from the bases
of the arms; sometimes between the centre and the margin; and
in a few species, such as in Caryocrinus ornatus (Say), it is placed
at the edge of the cup, between the bases of two of the arms.
It is often level with the surface, but in many species it is in
the top of a long tube, the so-called proboscis, which is frequently
longer than the arms, and projects above their extremities when
they are erect. The ambulacral grooves however are only found
in the arms. They are not continued along the surface of the
body to the mouth, as in the Star-fishes and recent Crinoids; and
unless, therefore, there be some other provision made for their
entrance, it is difficult to see how the ambulacral canals, nerves
and blood-vessels could communicate with the interior. In those
species with the mouth not elevated they might find their way along
the surface, but it is improbable that they could do so without
leaving some trace of their passage; and in Crinoids with a
proboscis it appears impossible that this course could be followed
at all. Provided therefore the usual description of the paleozoic
Crinoids be correct, 7.¢., that they have only one aperture, then
their ambulacral system must have been totally disconnected from
the interior of the animal—a supposition that would be contrary to
all the analogies furnished by the structure of the other groups of
the Echinodermata.

I have long been of opinion, that at the bases of the arms of the
extinct species there were special apertures provided for the passage
of the ambulacral vessels, but the evidence in my possession did not
appear suflicient of itself to warrant the publication of such a view.
Having had however, within the last few months, opportunities of
studying a large number of specimens in the collections of England
and France, I am now satisfied that there can be no doubt about
the matter. It is quite certain, that a great many of the extinct
Crinoids had either five, ten, twenty, or more of these openings,
and that through them the vessels of the ambulacra passed from
the grooves of the arms directly into the visceral cavity. While
examining the magnificent collection of the Geological Survey of
the United Kingdom I found many species which exhibit these aper-
tures in a most perfect state of preservation; and upon consulting
Mr. Thomas A. Huxley, F.R.S., who is profoundly acquainted with
the details of the structure of all the orders of the Echinodermata,

STRUCTURE OF THE CYSTIDEA. we

I was delighted to find that he had already arrived at the same
results, and had it in view to prepare a paper upon the subject for
the ‘Transactions of the Geological Society.” Upon my informing
him however that I was also about to publish the same discovery in
this decade, he in the most liberal manner made over his materials
to me, and I am thus enabled to give a figure of Actinocrinus rugosus,
which shews the course of the ambulacra under the ventral surface.

The principal difficulty in proving the existence of these orifices
is to find specimens so little mutilated at the base of the arms as to
exhibit the apertures with their margins uninjured. Hundreds of
examples occur with large, irregular openings, but as the edges are
fractured all around it is impossible to say whether or not there were
originally any natural apertures. It is only in individuals which
have been well preserved, and carefully collected and cleaned, that
the facts can be clearly observed. In some of the species the
apertures are exceedingly small, and so filled with crystalline matter
that they can only be seen very indistinctly. In Caryocrinus ornatus
(Say), for instance, there are certainly indications of the existence of
minute apertures, yet in the best specimens I have seen it would be
hazardous to assert it positively. In all the species of Rhodocrinus,
Actinocrinus and Platycrinus, the apertures are in general large and
easily observed. Most of the Lower Silurian specimens are in such
a condition that nothing can be determined with certainty concerning
any of the orifices. In one species from the Chazy and two from
the Trenton limestone, all of the genus Hybocrinus, I have however
ascertained their existence.

The following are some of the species in which I have seen clearly
that these apertures actually do penetrate through into the interior
of the visceral cavity :—

1. Eucalyptocrinus decorus (Phillips).—In this remarkable Crinoid
the arms are always found closed into the niche-like. divisions of the
proboscis and ventral portion of the cup. It is one of those species
whose structure renders a passage for the ambulacral canals through
the mouth almost impossible, as the orifice is situated in the apex of
a tube that projects above the extremities of the arms. In order to
enter the body in that direction, the vessels, after descending the
groove on the inside of the arm, could only proceed by climbing the
outside of the proboscis, by which course the projecting knob of
plates at the top would have to be surmounted. A more inconve-
nient route could scarcely be imagined, and we find that nature
has provided a much shorter one. While collecting fossils in the .

24 STRUCTURE OF THE CYSTIDE.

Niagara limestone last year, I procured at Thorold, near the Welland
Canal, a specimen which had been split in two from the apex
downward. I found only a portion of one of the halves. The
cavity of the body and proboscis had been filled with some soft
material, which, upon exposure to the weather, had totally disap-
peared, thus exposing the structure of the inside of the cup as
distinctly as could be desired.

Fig. 3. Fragment of Eucalyptocrinus decorus (Phillips), shewing six
of the ambulacral orifices.

There are two orifices at the base of each arm, and consequently
twenty in all, as this species has ten arms. The specimen only
retains six. They are of an oval shape, about one line in length
and one-third of a line in greatest width. Each pair is separated by
a small elongated ridge-like plate or process, which cannot be seen
on the outside of the cup. All the inter-radials which are situated
in the same level with the apertures have at each of their upper
angles a sharp process, which projects inwards about half-a-line.
(In figure 3, if the dotted line from the letter @ were continued, it
would cross the,centres of the apertures and inter-radials here referred
to.) The processes are above the line, and cannot be shewn by
wood-engraving. The small plates which separate the two pores
of each pair of the orifices have also each a similar process, between
which and the process of the contiguous inter-radial there is a very
narrow passage from the orifice upwards; and it is possible that the
ambulacral canals took an ascending course by this route. after
gaining the interior. Upon such points however of the internal
structure of the Crinoids, all that can be offered perhaps for an age
yet to come must be merely conjectural. The main fact proved by
this specimen is the existence of the ambulacral orifices at the base

/

STRUCTURE OF THE CYSTIDEA. 25

of the arms, and that consequently it was not necessary for the
_ vessels to climb the proboscis in order to reach the interior.

Fig. 4. Side view of a fragment of H. pristinus.
Fig. 5. The same, seen from above, shewing the continuation of
the ambulacral grooves of the arms into the interior.

2. Hybocrinus pristinus, H. conicus, and H. tumidus, (Billings,) have
five ambulacral orifices each, and they are formed according to a
plan which will be found somewhat common among the species of
those genera which have short cup-shaped or round bodies, such as
Cyathocrinus, Poteriocrinus, Dendrocrinus and others. The first radial
plate has a projection of the central portion of the upper margin,
which folds round and makes a conspicuous rounded channel which
descends along the inside of the plate to the interior. The upper
edge has a horse-shoe form, corresponding exactly to the first joint
of the arm which is seated upon it. These species shew that
generally the notches which we see in the detached first radial
plates of so many others are only continuations of the grooves of
the arms into the interior.

3. LEhodocrinus bursa (Phillips)—Good specimens of this species
exhibit very distinctly ten ambulacral openings. They penetrate into
the interior at about one-half the height of the body, and their margins
are formed on the lower sides by a semi-circular notch in the upper
edge of the second plate of each of the secondary rays, and on the
upper by several of the small abdominal plates. In no other
species is there more unequivocal evidence of the existence of these
openings, but they are accompanied by a structure which seems to
indicate two sets of arms placed one above the other. Beneath the
orifices there are two articular surfaces, which mark the bases of
two arms; and above each pair of the orifices there is a projection,
which also much resembles the base of one or two more arms.
They are very accurately figured in Phillips’ “ Geology of Yorkshire,”
vol. ii. pl. v. figs. 23, 24, 25. I shall introduce one of these figures
here, in order to shew their peculiar structure :—

26 STRUCTURE OF THE CYSTIDEA.

Fig. 6. One of the rays of Rhodocrinus bursa (Phillips).

In this figure 7, 7, 7, are the three primary radials; s, s, the
secondaries; a, 0, the ambulacral orifices; 6, the five basal plates ;
2, two of the sub-radials; and a, what appears to be the place of a
pair of arms. In some of the specimens this feature is exhibited
so prominently that it strongly impresses the observer with the idea
of two tiers of brachial appendages. It may be however that there
were projecting from this part of the vault a set of large spines
corresponding in numbers with the arms. Rhodocrinus differs in no
respect from Thysanocrinus (Hall), provided we still depend for
generic characters altogether on the structure of the cup below the
point where the arms become free. But if the form of the vault
be taken into account, then the English genus is different from the
American.

The vault in R. bursa rises above the ambulacral orifices, and in
fact projects a little outward over them, so that they penetrate into
the side of the cup, below the margin, instead of being placed
immediately above and inside of the margin, which, from the
position of the arms, must be their place in Thysanocrinus.

4. Actinocrinus rugosus.—For the structure of this interesting
species I am indebted to Mr. Huxley, and the figures given in the
following page were drawn from a specimen in his possession.

In this species the plates are very thick, and the ventral side
rises dome-shaped above the point of attachment of the arms, so
that the ambulacral orifices are rather nearer the bottom than the
top of the body. The proboscis is excentric, large, and not perpen-
dicular, but projecting obliquely, so that when the arms were closed
its apex probably was thrust out between two of them on one side.
The mouth appears to have been closed by a number of small plates,
which were no doubt so connected by an extensible membrane as

STRUCTURE OF THE CYSTIDEA. 27

to permit of a considerable amount of dilation. The ambulacral
orifices are ten in number, and enter the cup at the base of the arms.
They do not however immediately penetrate into the cavity of the
body, but ascend towards the top of the ventral elevation by five
tunnel-like passages, which lie under the external plates and extend
nearly to the apex of the dome. These passages are floored by a
series of plates, which form an elongated arch under them. They do
not reach the centre at the summit, but are discontinued at about
two-thirds the distance from the base of the arms.

eee

WS

Fig. 7. <A specimen of 4. rugosus, shewing the course of the ambulacral
channels from the orifices towards the summit. The exterior
plates have been removed, leaving the floors of the channels
visible. They terminate below the summit, at the points
indicated by the lines diverging from a.

Fig. 8. View of the opposite side of the same specimen.

In order to ascertain whether these tubes might exist in other
individuals, I procured several other specimens from the dealers in
fossils and, upon removing the outer plates, found the same structure
in all. Upon grinding down-the summit of one of these, I find that
the tubes do not reach the top of the vault, but terminate at a short
distance below.

28 STRUCTURE OF THE CYSTIDEA.

Figure 9 is a view of a section made transversely through the
upper half of the ventral dome of aspecimen. The unshaded border
shews the great thickness ef the plates of the vault. The tubes and
visceral cavity are filled with soft light-brown rock. mis the mouth,
which is cut through; at 1 is a tube, the floor of which has thinned
out so, that it already communicates with the visceral cavity; a2 is
another, with the floor remaining; 3 and 4 are in communication
with the interior, although in consequence of the truncation being
a little oblique, they are exposed at a lower level than the others ;
5 is one with the external plates removed, leaving the bottom of
the channel exposed down to the arm. The floor extends upwards
four lines and a-half, and thins out just before it reaches the level of
the truncation.

The important additional fact established by these specimens, and
first ascertained by Mr. Huxley, is that at least in this species the
ambulacral vessels, after entering the body, turn upwards towards
the centre of the summit.

2. eae

Fig. 10. Fig. 11.

5. Actinocrinus stellaris (DeKoninck) has twenty ambulacral orifices
which enter the body from the second or third plates of the tertiary
rays. The ventral dome is very large, and at its base forms five
projecting lobes, in each of which are four of the orifices. Figure 10
represents one of the lobes of a specimen in my possession. One
of the orifices (fig. 10) is perfect, and shews that the margin of the
upper half is formed of five small plates, while the lower side lies
in the excavation in the tertiary radial plate. This excavation is
simply the ambulacral groove, which is here continued into the
body. Fig. 11 is an enlarged view of another orifice. A fragment
of the vault of this species, which is empty, exhibits a broad rounded
furrow, bounded on each side by two angular ridges running towards
the summit (fig. 12). It occupies the position of one of the internal
channels in A. amphora, and no doubt, as in that species, served to

STRUCTURE OF THE CYSTIDEA. 29

conduct the ambulacral canals towards the summit of the ventral
side.

6. Pradocrinus Baylii (deVerneuil*), a species which occurs in the
Devonian rocks of Sabero, in Spain, has ten ambulacral apertures
very clearly exhibited. The ventral surface of this fine species
consists of numerous small plates, the mouth is excentric, and there
are ten arms. The apertures are formed by a notch in the second
plate of the secondary radials on one side, and on the other by
several small ventral plates, as in Actinocrinus stellaris. Good
specimens are in the collection of the Geological Survey of the
United Kingdom, Jermyn Street. See also the figures given in the
work cited.

Among the species figured in various works, the following are
some that shew these apertures very distinctly :—

Fig. 14.

Figure 13. Dolatocrinus lacus (Lyon). Side view.
‘« 14. Diagram of one of the rays.
“15. View of the ventral surface.

Dolatocrinus lacus occurs abundantly in the Devonian formation
of Kentucky, and the above figures are taken from the beautifully
illustrated Report of Mr. Sidney S. Lyon, of the Geological Survey
of that State, published in 1857. (Plate iv. figs. 2, 2a, 2b.) There
are ten ambulacral orifices, and the mouth is central, but there are
no grooves from it to the arms. The generic figure given by
Mr. Lyon—of which the above fig. 14 is a portion—shews all the
apertures. In the same plate there are several figures of another
species, Vasocrinus valens (Lyon), with five orifices; but of these
only the grooves on the inner margins of the primary radials are
preserved. All the ventral plates appear to be absent, and it

ce Sa IE ee a Ad LE ENE BEN a Rk

* Bulletin Geo. Soc. France, 2d series, 1850, vol. vii. page 184, plate iv. fig. 11.

30 STRUCTURE OF THE CYSTIDEA.

cannot thus be seen whether the mouth was central, proboscidiform
or otherwise, or whether the grooves of the arms were continued
along the surface.

The following three figures are taken from the Report of the
Geological Survey of Missouri, vol. i. part ii. plate A. Dr. Shumard,
the Palzontologist of Missouri, in his descriptions of the species,
expressly recognizes these apertures. He says that the example of
A. rotundus figured ‘exhibits twenty-one arm-openings.” (p. 191.)
Of A. Verneuilianus he states “the vault consists of numerous small
pieces, united so as to form a nearly smooth convex surface.
Proboscis, sub-central. Arms, unknown; the number of arm-openings
iu the specimens under examination varies from fourteen to fifteen.”
(p.194.) In the same plate there are figured A. Christy: (Shumard),
A. Missouriensis (Shumard), A. pyriformis (Shumard), and A. parvus
(Shumard), each of which exhibits a belt of ambulacral apertures.

Figure 16. .Actinocrinus rotundus (Yandell and Shumard).
“ 17. Actinocrinus Konincki (Shumard).
“ 18. Actinocrinus Vernewilianus (Shumard).

The above figures and remarks, if not sufficient to establish the
existence of these orifices, may, it is hoped, at all events indicate that
the subject is worthy of investigation. There are many species that
represented in the publications of different writers which shew that
there are some very interesting questions relating to the structure
of the ambulacra of the Crinoids yet to be worked out, and that
probably principles for both zoological and geological classification
may be drawn from this source. See the following, in Pictet’s
Traité de Palaontologie, Plate XCIX. :—Fig. 1. Solanocrinus costatus
(Goldfuss). Fig. 2. S. Jegeri (Goldfuss). Fig.3. Decamerus mysticus
(Hagenow). Fig. 20. Calliocrinus costatus (Hisinger). Plate C.
Fig. 2. Haplocrinus mespiliformis (Reemer). Fig.3. Coccocrinus rosaceus
(Miiller); and Fig. 7. Gasterocoma antiqua (Goldfuss).

STRUCTURE OF THE CYSTIDEA. 31

IV. The Cystidee.

Concerning the functions of the apertures of the Cystidez there
has always been much doubt; and in fact, at the present moment,
the only point that can be regarded as established by positive
evidence is, that the apical opening was the passage through which
the vessels of the ambulacra issued from the visceral cavity. All
the grooves of the arms or pinnule take their departure from it ;—
there are no other apertures so situated with respect to the brachial
furrows that they could have subserved this function, and therefore -
the conclusion, that it was the ambulacral orifice, seems as well
founded as could be desired. There is not the least proof, except
the remote analogies furnished by the Star-fishes and recent Crinoids,
that it was the mouth; and in selecting a name, therefore, the safest
course is to be guided by some known character, rather than resort
to the unknown.

The large opening in the side, called the mouth in this memoir,
has been usually described as a genital or ovarian aperture, a view
first entertained by the late Baron Leopold von Buch, and accepted
with more or less hesitation by most authors up to the present time.
The idea originated altogether in the supposition that the Cystideze
were armless, and consequently that the ovaries could not have been
situated outside of the body. The following is von Buch’s descrip-
tion of the Cystideze :—

“The Cystidee were natural bodies supported on a stem or pedicle, which was
attached to the ground; their surface, more or less spherical, was covered by a great
number of polyhedral plates, accurately fitted to one another, and between these plates
_ were certain openings necessary for the performance of the animal functions ; but from

none of these did arms proceed resembling those of the Crinoidee. The animal was
conpletely without arms.

“With regard to the openings on the surface, we find in all the Cystide :—1st. That
the mouth was planted in the central part of the upper surface, generally in a movable
proboscis covered with minute plates. 2nd. That besides this mouth, and close to it,
there is generally, if not always, a small anal orifice penetrating the plates, but not
itself surrounded with any plates peculiar to it. 3d. That further towards the middle,
but almost invariably on the upper half of the body on which the mouth is placed,
there rises a round or oval aperture, not connected with the mouth, and often covered
by a five or six-sided pyramid, which seems to be composed of as many little valves.
This probably forms the ovarian orifice of the animal.

“These openings, with the exception of the mouth, are not found to exist when arms
begin to be developed from the upper'surface ; and we may easily understand this when
we remember that in the latter case the ovaries are carried out with the arms beyond
the rim of the cup-like body, so that a separate opening for them would be useless. In
all Cystidez the presence of these ovarian orifices is however manifestly essential.” —

Von Buch: Uber Cystideen, Berlin, 1845. Translated in the Journal of the Geological
Society, May, 1845.

32 STRUCTURE OF THE CYSTIDEZ.

It is quite clear from the above extracts that the only reason upon
which von Buch founded his opinion was, that the Cystidez are
without arms. From the expressions in italics, there can be little
doubt that if he had examined specimens with arms well preserved,
such as some of those figured in this decade, the idea of an ovarian
aperture would scarcely have occurred to him; in fact it would, to
use his own words, have appeared to him ‘useless.’ Since therefore
it is now beyond all question that the Cystidez had true crinoidal
arms, the only reason that ever suggested to any one the necessity
of a genital aperture has no longer an existence, and the question
remains exactly as it was before the publication of his memoir on
the Cystidex.

If then we should no longer regard it in the light of a genital
opening, the next question to be decided is, What was its function?
I believe that in those species which were provided with an anus,
it was the mouth, and in the others both mouth and anus. The
following are my reasons :—

1. In Echinospherites aurantium, Caryocystites granatum, and many
others, there is a well-defined anal aperture; and if the ambulacral
orifice were also the mouth, then it would follow that the lateral
opening had no function. The same would be true of the genera
Echano-encrinites, Apiocystites and Callocystites, all of which are said
to exhibit anal pores near the summit. But if the apical opening
be an ambulacral orifice only, then there is no place for the mouth
but in the lateral aperture.

2. The position of the organ in question is not inconsistent with
the idea of its being an oral aperture, because in many of the
Echinodermata we find it not only in the side but even on the under
surface of the body. Thus in the Echinide the mouth is in the under
side, and the anus either in the very highest part of the body or in
the side. The Star-fish always crawls with his mouth under, and so
do the Ophiura, Euryale and Comatula. The fact therefore that the
lateral aperture of the Cystidea is lower down than the anus is no
proof that it is not the mouth, but directly the reverse, since it is
the natural position for the organ in the class.

Even among the true Crinoids, we have at least one species with
the mouth in the side, as represented by the following wood-cut,
taken from the figure in plate C. of Pictet’s Atlas. The genus has
five basal plates and five radials; the mouth penetrates the large
inter-radial, and there appears to be five ambulacral orifices. There
can be no doubt but that this species is a true Crinoid, as the rays

STRUCTURE OF THE CYSTIDEA. 33

originate in the sides and not in the centre of the ventral surface,
as in the Cystidez.

aaa

Fig. 19. Epactocrinus irregularis (Wirtgen and Zeiler).

3. In Pentacrinus caput-Meduse, the mouth, although combined
with the ambulacral orifice, has a structure similar to that of the
Cystideze. This fact is pointed out by MM. Koninck and Le Hon in
their magnificent work upon the Crinoids of the Carboniferous rocks
of Belgium.* The observations were made upon a fine specimen
captured by a fisherman in the harbor of Moule, Island of Guada-
loupe, and sent by Dr. Duchassaing to M. Michelin. The following
is Duchassaing’s description of the mouth :—

“The mouth of the Encrinite is surrounded by five lips, and can be seen only when
these five lips are opened. It then appears as a small round aperture about two lines
in diameter. The lips are not free, and can be opened to the extent of about three
lines. They are adherent to the five furrows which departing from the commissures
are prolonged to the circumference of the disc. Mastication is effected, not by the

mouth, but by the lips, which are armed to that effect with small stiff spines. As to
nourishment, I found the dektris of small crustaceans.”

Upon the above extract, MM. Koninck and Le Hon make the
following remarks :

“Tt is perhaps well to observe here, that it results from the remarks of M. Duchas-
saing that what he calls lips are veritable triangular valves, hard, and armed at
their points and internal surfaces, and designed to hold and crush Crustaceans and
other animals upon which the Pentacrinus appears to feed.

‘¢ They have exactly the same form as the ossicles which in the Cystidez cover the
aperture which L. von Buch has considered as an ovarian orifice.

“We have no doubt that the illustrious paleontologist whose recent death science
deplores, did not recognize the true function of that opening. We are persuaded that
it served the same purposes as those which have been observed iu Pentacrinus. Our
conviction is so much the more profound that we have never been able to discover upon
the triangular valves of the Cystidez the least trace of a perforation, and that those
which cover the mouth of Pentacrinus offer nothing more.

“It would be besides very extraordinary that these calcareous plates whose position
and form are perfectly identical in these animals, belonging to the same class, should

* Recherches sur les Crinoids du Terrain Carbonifére de la Belgique. Par L. De
Koninck et H. Le Hon, 1844; page 33 et seq.

Cc

34 STRUCTURE OF THE CYSTIDEA.

be designed for such very different purposes as would result from the adoption of the
opinion of L. von Buch, on the one hand, relative to the use of the triangular plates
of the Cystidez, and, on the other, from the direct observations made by Dr. Duchas-
saing.”

From the above remarks, it is evident that MM. Koninck and Le
Hon, who have profoundly studied the Crinoidez, are of opinion that
the ovarian pyramid of the Cystidez is the exact homologue of the
buceal apparatus of Pentacrinus, a view in the correctness of which I
entirely concur. The only difference is that in Pentacrinus the ambu-
lacral orifice with its grooves is combined with the mouth and its
pyramid of valves, while in the Cystidez they are separate. Von
Buch was of the opinion that the five valves of the Cystideze were
perforated by five minute pores which were the ovarian pores. The
organ would then present a greater resemblance to the ordinary
arrangement of the reproductive system in the Echinodermata. In
most of the families of this class when the ovaries are contained in the
visceral cavity, there are many of them, and they have their orifices
disposed according to the radiated division of the body. Thus in the
Echinide there are five ovarian pores, sometimes it is true, reduced
to four in the abnormal forms; in the Blastoidea there are five, in
the Ophiuride ten, and in many of the Star-fishes five or ten.*
It is thus contrary to analogy that when an Echinoderm has the
reproductive system included in the cavity of the body, there should
be but one genital opening.

4, If we consider the relative dimensions of the several apertures,
we find that in general the mouth is larger than the anus.
Although in the fossil Echinide the anal aperture often appears
to be as large as the oral, yet this is owing to the destruction of a
portion of it. In the living specimens the opening is covered over
with the exception of a mere pore, while the mouth is of a large
size. In the Star-fishes, wherever an anus exists it is always many
times smaller than the mouth. In Glyptocystites multiporus the apical
aperture is only one-tenth the size of the lateral opening; in
Malocystites Murchisoni one-ninth; in Echino-encrinites angulosus one-
ninth; in Hemicosmites pyriformis it consists of a minute three-rayed
fissure (see the beautiful figure in plate iv. fig. 5, Miiller, Uber den
Bau der Echinodermen) ; in all the species of Pleurocystates, although
it has not been observed, yet the structure of the parts proves that

* See the figures of the genital pores of Asteracanthion rubens and Solaster papposus,
Plate xii. System der Asteriden, von Miller und Troschel.

STRUCTURE OF THE CYSTIDEA. 35

it must be exceedingly small. The same may be said of almost
every Cystidean that has been described and figured: the lateral
aperture is ever the largest, and when it is considered that the one
in the apex, whether it be the mouth or not, always receives the
ambulacral vessels by which its capacity is further diminished, the
argument has still greater force.

5. The objection that it is contrary to analogy that the mouth
of an Echinoderm should be situated any where else than in the
central point where the grooves meet, is not borne out by the facts,
because in a vast number of species of Crinoidea, the group most
nearly related to Cystidea, it is not so placed. The grooves do not
come near the mouth in the palzeozoic Crinoids, and therefore the
analogy wholly fails.

6. With respect to the bearing of the arrangement of the
apertures of the recent Crinoids upon this question, there appears
at first sight to be some difficulty, as in these there are two
orifices, one of which not only receives the ambulacra, but is also
the mouth, while the other is said to be the anus. If we were
to be guided altogether by this analogy, the lateral opening of the
Cystideze would be, at least in some species, the anal aperture.
There is however a great difference in the structure of the two
groups. Any one who will take the trouble to examine, the figures
of the species given in most elementary works, will see that the
rays of Pentacrinus caput-Medusé spring from the very base of the
body. The first radial plates of all the rays rest upon the upper.
joint of the column, and the others follow in succession up the
sides. If the point of the attachment of the column be the dorsal
side, then the rays are developed from the centre of the back.
The same structure occurs in Comatula. But in the Cystidez it is
the very reverse: the rays spring from the centre of the ventral
side. The whole of the cup of the Crinoid is radiated, but in the
Cystidean it presents.no trace of a radial arrangement: all below
the apex is unradiated; the bases of the arms are crowded together,
so that they all originate in a narrow space upon the upper side
of the body, where they surround the ambulacral orifice. The
first primary radial plates, which in Pentacrinus rest upon the
column, are in the Cystidezw transferred to the opposite pole of
the body, and are there represented by the cirele of plates which
surround the ambulacral orifice. This view of the structure of the
Cystideze was first put forth by Volborth, and afterwards adopted
by Professor J. Miller of Berlin. Neither of those authors however

36 STRUCTURE OF THE CYSTIDEA.

appear to have been aware of the existence of special orifices in
the Crinoids for the passage of the ambulacral vessels, and hence
they still regarded the apical aperture as the mouth. Volborth says:

“All the Cystidesw were, like Crinoids, provided with articulated arms; and this
statement is not mere hypothesis, but is the result of philosophical induction from
distinct well-grounded facts, determined by observation—by the actual presence of arms
in some species, and the presence of tentacle furrows in others. The Cystide were
also true Crinoids. Either in the young state or throughout life they were attached
by an articulated stalk, or by a pedicle, either to the bottom of the sea or to foreign
bodies. They had articulated arms which, as in Crinoidex, proceeded from the dorsal
pole of the cuticular skeleton. Diametrically opposite to the orifice of the pedicle is
placed the buccal orifice, and generally close to it is the sub-central anal orifice.
The cup differs however from that of the Crinoids, by such a predominance of the
dorsal side over the ventral, that the latter is often reduced to a minimum, consisting
only of the orifice of the mouth, so that the arms appear to be much nearer the mouth
than is the case with Crinoids.”—Volborth on the Arms of Cystidee. Trans. Min. Soc.
of St. Petersburgh, 1845—6.

Professor Miiller, whose extraordinary researches in the depart-
ment of the development of the recent Echinodermata have never
been excelled, says :—

“The development of the antambulacral side of the radii in Crinoids takes place
either from the very base of the calyx, or from its circumference, or in the neighborhood
of the mouth, as in most Cystidee. In the latter case the calyx presents no radial
arrangement of plates from the base to the immediate neighborhood of the mouth; it
begins only at the mouth in the oral arms, whose ambulacral grooves however lead to
the mouth, and, like the articulated antambulacral surface of the arms, present no
traces of the general plan of the Echinoderms. Hence it is intelligible why, so long as
the Cystidez were held to be armless, the radial arrangement of the Echinoderm was
unrecognized.” —Uber den Bau der Echinodermen, p. 55. Translated by Mr. Huxley in
the Annals of Natural History, 2d series, vol. xiii. p.242. April, 1854.

Professor Miiller terms the dorsal side of the arm of a Crinoid
antambulacral, thereby distinguishing it from the ventral side,
whch is grooved and holds the ambulacra. The genital and ocular
plates of the sea-urchins are also antambulacral, but they are few
in number, and usually confined to one spot in the centre of the
back; and therefore the principles contained in the above extract
may be applied to shew that the Cystidez are not so nearly related
to the recent Crinoids as they are to the palzozoic species.

a. If we take a sea-urchin and placing it with the mouth upwards,
which is the usual position of that organ in the Crinoids, then
imagine a plane to be projected horizontally through the circular
area occupied by the antambulacral plates, the whole of the body
of the animal will lie above the plane. Its skeleton is composed

STRUCTURE OF THE CYSTIDEA. 36

altogether of ambulacral and interambulacral plates, with the
exception of the small space in the back, consisting of the ocular
and genital plates.

b. If a similar plane be extended through the lower edges of the
first primary radials of Pentacrinus caput-Meduse, the body, as in the
sea-urchin, will lie above it; but then it is covered at the sides by
the plates of the rays, and on its upper surface by the ventral plates,
all of which are antambulacral.

c. In such Crinoids as the species of Poteriocrinus and Cyathocrinus,
which have two rows of plates below the radii, a plane through
the lower points of the primary radials would have about one-half
of the body below it, and the other half above. Here we see a
tendency in the radiated skeleton to transfer its base from the dorsal
to the ventral side; and it is interesting to perceive that in Crinoids
of this structure we first find species which indicate their approach
to the Cystidez by the exhibition of poriferous areas, which are at
least analagous to the pectinated rhombs of that group. These
exist in Porocrinus conicus (Billings) of the Trenton limestone, and
Caryocrinus ornatus (Say) of the Niagara group.

d. The Cystideans with a definite number of plates, such as the
genera Echino-encrinites, Glyptocystites, Apiocystites and Prunocystites,
are certainly more nearly related to the Crinoids than those with
the body covered by a large and indefinite number, as, for instance,
Echino-spherites aurantium. The number five, so dominant in the
arrangement of the parts of the body in the Crinoids, is apparent in
these genera, although no trace of it can be seen in the spheeronites.
Thus in E. angulosus (see plate iii. fig. 1) there are four basal plates,
but one of these is hexagonal, and can be divided so as to make two,
which would be pentagonal like the other three. Above the basal
plates are three other series of five each. It may be granted that
the plates of the fourth series are the homologues of the five first
primary radials of Cyathocrinus planus (Miller), which form a circle
round the margin of the cup. When closely examined it will be
seen that in both the Crinoid and the Cystidean these plates are
notched in their upper margins by the ambulacral grooves; and it
is therefore probable that they are strictly the homologues of each
other.

If now in these two species we draw the plane as before, about
one-half the body of the Crinoid and nearly the whole of the Cysti-
dean will lie below it. The radiated skeleton in E. angulosus has
ascended from the base to the apex of the body, and it is there

38 STRUCTURE OF THE CYSTIDE.

compressed into so small a space that there is no longer any room
for the mouth in its centre. The organ is crowded outside of the
circle of radial plates, and lies lower down in the body. If the
arm-bearing plates of Caryocrinus ornatus—a species admitted to be
almost a Cystidean—were thus drawn together into the centre of
the ventral surface, the mouth would certainly be left outside,
because it is situated in the margin, between two of the arms.
It would not however on that account change its nature and
become a genital aperture.

e. In all the species with an indefinite number of plates the
difference is still greater. If we extend the plane through t
base of the arms in E. aurantium, we would have the very opposite
of what occurs in the instance of the sea-urchin. The body would
form a large globe-like expansion below the plane, while in the
sea-urchin it lies altogether above. The Cystideans of this type
inust be regarded as the extreme in une direction, and the KEchinidz
the extreme in another. Prof. Miller says:—‘‘In an Echinoderm
which remains antambulacral quite up to the mouth, and develops
arms only from the oral part of the calyx, we have at its maximum
that condition which in the Echinide is at its minimum. To borrow
the phraseology of the ‘Natur-philosophie,” we may say that the
calyx of a Pseudocrinites, Agelocrinites, Echinospherites, Echino-
encrinites, is the apex of an Echinus; it is however an expansion
of the apex large enough to enclose the whole of the intestines
of the animal, while in the Echinus these are invested for the most
part by the ambulacral zone of the perisoma.”—Uber den Bau der
Echinodermen, p. 16; Annals of Natural History, 2 ser. vol. xii. p. 9.

If now we place the above forms in series arranged according to
the greater or less concentration of the antambulacral side of the
rays towards the centre of the back, all the Crinoids would lie
between the Echinide and the Cystideee. Thus:

In the Echinide the antambulacral radiated skeleton is absorbed
into the middle of the back.

In Pentacrinus and Comatula it is also strongly concentrated, but
covers the whole of the back and sides.

In Thysanocrinus (Hall), a genus which appears in the Trenton
limestone, the unradiated space at the base of the cup is larger
than it is in Pentacrinus. There are two series of plates below the
first primary radials. There is then in this genus a tendency in the
radiated portion of the skeleton to depart from the centre of the
back and take its origin from the upper part of the body.

STRUCTURE OF THE CYSTIDEA. 39

When we examine a specimen of any species of Cyathocrinus,
we perceive another step in the same direction. There are, as m
the last genus, two rows of plates below the radii; but, in addition
to this character, the ventral side of the animal does not rise above
the upper margins of the first primary radials. The radiated
skeleton forms a belt round the upper part of the body, and
Cyathocrinus is therefore nearer to Hchino-encrinites than is Penia-
erinus, because the bases of the rays are nearer the ventral side.

Many other examples might be given in illustration of this point,
were it necessary. The general conclusions I draw from the whole
of the above are, that when we compare the recent and ancient
Crinoids with the Cystidez, the latter two are seen to be the most
nearly related upon the whole—that those genera with two series
plates below the radii are the nearest to the Cystidez, and that the
genera with the rays developed from the base are the most distant
of the Crinoids, the Echinide being still further away.

If these conclusions be correct, then the/apertures of the Cystidez
should be more properly compared with those of the paleeozoic
than with those of the recent Crinoidez. These latter have no
special ambulacral orifice, the function being exercised through the -
mouth. But the paleozoic Crinoids have the ambulacral orifices
separate from the mouth, and so it would most probably be in the
Cystideee.

Classification of the Cystidee.

The following passage, extracted from the memoir of Professor
Miller on the Structure of the Echinoderms, contains the outlines
of a system of classification which will most probably be generally
adopted. It should be borne in mind that he was not aware of the
existence of the ambulacral orifices in the Crinoids, otherwise no
doubt some portion of his paper would have been directed to their
examination :—

“ Cystidee.— Among the Crinoids the Cystidee@ of L. von Buch form
a group which is distinguished by the inclusion of the genital organs,
together with the other organs, in the calyx. In the Pentacrinites
and Comaiule on the other hand, the sexual organs are attached to the
pinnulz of the arms; in those. Crinoids which have only one calycine
opening (mouth), as Actinocrinus, Platycrinus, &c., the exclusion of
the sexual organs from the calyx is at once rendered probable by the

40 STRUCTURE OF THE CYSTIDEA.

absence of any aperture corresponding with them. The Cystidee, on
the other hand, have at least two and sometimes three apertures to
their calyx, one of which, distinguished by its valvular closure, is found
in no other Crinoids than the Cystzdee. L. von Buch has determined
that this valvular pyramid is the genital aperture.* We owe to him
the recognition of the close alliance of these forms with the Crinoids,
and at the same time of their peculiarities, the exact analysis of their
calyces, and the exposition of their genera. That they are not armless,
as had hitherto been generally supposed, was first observed by A.
von Volborth, who discovered the arms in Echino-encrinus angulosus
and striatus, subsequently in Echinospherites aurantium, where they
proceed from the mouth. The figures of the Duke of Leuchtenberg,
and those of Volborth of Spheronites Leuchtenbergii and Protocrinites
oviformis would indicate the presence of arms in these also, although
they have not been actually obtained. In fact, branched grooves
run from the mouth over a great part of the calyx ; the branches of
the grooves however end in papillze of the calyx, whick must be
regarded as points of origin of arms—a circumstance so much the
more remarkable, as it would follow that the arms of these Cystrdew
must have had a position far removed from the mouth (Verhandl. d.
Konigl. Mineralog. Gesellschaft zu Petersburg, 1845-6, Petersb. 1849).
A specimen of Spheronates. Leuchtenbergui in von Buch’s collection
agrees exactly with these figures. When, in his second essay, L. von
Buch founded the order Cystidee@ (1844), the oral arms of Echino-
encrinus Were already known. He did not regard them as Crinoid
arms, but called them feelers. With a correct foresight he even then
arranged the Pseudocrinites and Agelocrinus, with long arms passing
from the oral part of the calyx, among the Cystidee, but was not
inclined to consider these processes as true arms. He had even in
1840 termed the remains of the three arm-like processes in Hemiscosmites
arms or proboscides, but was led away from a just comprehension of
their nature by comparing them with oral tubes.

‘In his beautiful monograph on the British Cystideans (Mem.
Geol. Survey, t. ii. Lond. 1848) Forbes has increased the number
of forms with oral arms. He divides the Cystide@ into,—I1st, those
with arms: Pseudocrinites, Apiocystites, Agelocrinites—2nd, those with

*In my copy of Miller, “‘Uber den Bau der Echinodermen,” the following sentence
follows here :—‘ Fine Vermuthung, die freilich nicht sicher beweisen werden konnte,”
which may be thus rendered: “.:n opinion which surely cannot be positively proved.”
Miller appears therefore to have believed that Von Buch’s demonstration was not
complete.

STRUCTURE OF THE CYSTIDEA. 4]

oral pinnule: Prunocystites—and 3rd, armless forms: Caryocystites
and Spheronites ; to which latter the British form Echino-encrinus
is added. Forbes considers that the arms observed by Volborth
in the Russian species of Echino-cencrinus are oral pinnule. The
oral arms of Echino-encrinus and Prunocystities are articulated in two
series. Volborth observed that in the former they are beset with
small plates upon their ambulacral surfaces, which he calls
tentacles, remarking that pinnule are absent. These plates have
the characters of marginal plates, which in the Crinoids (Pentacrinus)
occur on the arms as well as on the pinnule. In Echino-encrinus
angulosus the remains of six arms were preseat. That this number
does not agree with the five depressions which usually surround
the mouth is explained by the fact, that the number of these
facets varies; Von Buch states that there are five or six; and I
possess a specimen with eight round depressions about the mouth,
which are united with the mouth by grooves. Echino-encrinus
striatus possesses, according to Volborth, together with a very
much narrower pointed oral extremity of the calyx, only two
much iarger opposed oral arms, which have the same structure
as in Echino-encrinus angulosus. From their relations, however,
it is probable that these are not pinnulce, but arms; for it is not
usual for pinnule to be isolated. If they both belong to a single
ambulacrum how are we to imagine a single ambulacrum in this
locality in the immediate neighbourhood of the mouth? If,
however, they belong to two different ambulacra, they can, as
solitary structures, be only arms.

“The arms of Echinosphe@rites aurantium, Wahlenb. (Sphe@ronites
aurantium, His.) have essentially exactly the same relations as
Volborth has described and figured. In such well-preserved
Specimens as now lie before me, the origins of three articulated
arms at the oral region of the calyx are recognizable. The five
uppermost calycine plates are raised into a three-sided pyramid
transversely truncated above, whose obtuse edges are prolonged
into the arms. Two sides of the pyramid are broader than the
third. The sutures between the five pieces are so disposed that
two of them are situated upon the broader side of the pyramid,
the three others in the obtuse edges. Two supplementary pieves,

however, are added to the five principal portions of the pyramid, ——

and extend from the calyx into two of the angular sutures. The
pore-grooves of the plates of the calyx extend only on to the
lower portion of the circumference of all the seven pieces. The

42 STRUCTURE OF THE CYSTIDE.

arms immediately subdivide again. From the oral aperture
grooves beset with marginal plates, pass on to the arms. For
the rest, the division of the arms shows that they are arms, and
not pinnule. Whether these arms, like those of a few other
Cystideans, as Pseudocrinites, were provided with articulated pinnule,
cannot be decided, since they are broken short off. Whether the
Caryocistites possessed arms is not as yet known, but it can hardly
be doubted, since they are not certainly distinguishable from
Echinospherites.

‘“‘In Hemicosmites three of the six uppermost plates of the calyx
are provided with an insection, which arises from the tri-radiate—
median calycine opening. ach of the insections is continued
into a groove; the groove terminates after a slight expansion in
an elevation of the calyx which served for the attachment of an
arm. The elevation no longer lies on the plates of the uppermost,
but upon three of the plates of the second series. The elevation
exists only in specimens which are not worn down, and is beautifully
obvious in a specimen which M. Ewald has sent me. The tri-radiate
clefts of the calyx, and the calycine grooves continued from them,
are covered with minute plates which readily fall off. In the
specimens figured by L. Von Buch, they are still perfect, and form
a fine series of plates from the mouth to the ventral surface of
the three arms. In this series again, three delicate grooves are
distinguishable, as in Echinospherites aurantium, which correspond
with the subjacent clefts of the large plates of the calyx and
their grooves. In the always much worn specimen of Cryptocrinites
cerasus, no indications of arms have hitherto been observed.

“Forbes regards the Cystidee, like the Blastoidea, as sections of
the Echinoderms different from the Crinoids. The Spheronites were
already arranged among the Crinoids by reason of their stalks
before their arms were discovered, and we now have still more
reason for considering this to be their true position. Volborth
and Roemer consider the Cystidee as a group of Crinoids, which.
is also my own view. ‘The position of the the arms however,
must not be regarded as one of their characters ; for in Spheronites
Leuchtenbergit and Protocrinites oviformis the arms were situated
far away from the mouth, as in the other Crinoids.

“‘The suctorial feet of the Cystideans were unquestionably placed
as in Pentacrinus, on the ambulacral side of the arms and in the
ealycine grooves. In the introductory part of this essay however,
it has been demonstrated to be contrary to all analogy, that

STRUCTURE OF THE CYSTIDEA. 43

suctorial feet should exist in any Echinoderm upon the antam-
bulacral side of the persoma from the apical end to the arms,
or between the ambulacral radu. In the Cystidee therefore, the
whole calyx, with the exception of the calycine grooves, is to
be regarded as anambulacral.

“The genera Pentacrinus, Caryocrinus, and most Cystideans are
distinguished among the Crinoids by the existence of very peculiar
pores in the anambulacral plates of the calyx. Pentacrinus alone
has afforded the opportunity of an exact investigation of these pores.
I have described and figured them in the essay upon Pentacrinus.

“The interambulacral (interpalmar as well as intrapalmar) caly-
cine pores of Pentacrinus pierce the ventral calycine plates, and lead
beneath the inner membrane of the calyx. They possess no soft
external prolongations. In contrast with the ambulacral calycine
pores for feet, these may be called anambulacral calycine pores.
Their signification is not understood, only it is certain that they are
not passages for feet. A comparison with the respiratory pores
of the Asteride suggests itself; soft tubes project from these, with
regard to which Ehrenberg has shown (and I can confirm his
statement by my own observation,) that they are ceca, which are
indeed connected wiih the abdominal cavity, but are perfectly closed
externally.

“The calycine pores of Caryocrinus are equally without relation
to the arms; and thence, though differently distributed, resemble
the anambulacral calycine pores of Pentacrinus. They occupy the
antambulacral part of the calyx behind the arms as far as its base.

“Most Cystideans (Cryptocrinites cerasus excepted,) possess calycine
pores, which are distributed over a greater or smaller part of
the calyx without radiation and in a very peculiar manner. In
those forms with calycine grooves, as Protocrinites and Spheronates
Leuchtenbergui, these pores again appear to be anambulacral, since,
like the anambulacral pores of Peniacrinus, they are disposed in
the areas external to and between the ambulacral grooves; here
however, their distribution is far wider, since they extend as far
as the base.

“Two principal divisions have been made, according to the
distribution and combination of these pores :—

‘“‘T. Cystideans with pore-rhombs. The pores are disposed in
rhomboidal figures, the one-half of which belongs to one plate,
the other to its contiguous neighbour. Every two pores of these
rhombs appear to be invariably united by canals or grooves,

44 STRUCTURE OF THE CYSTIDEA.

which are visible either upon the outer or on the inner side of
the plates, in such a manner that the united pores belong to two
different adjacent plates.

“qa, Pore-rhombs without external connexion of the pores.
Hemicosmites and Caryocrinus ; in Hemicosmites the combining grooves
are according to Volborth, upon the inner surface of the plates.

“© b, In Echinospherites granatum, Wahlenb. (Caryocystites granatum,
v. B.), the pores are united by bands projecting externally, which
contain the connecting canal of the pores, and this canal is always
a single one between each pair of pores, or even a series of pores.*
The more importance is to be attached to this circumstance, as
the number of the calycine plates, even of the basal plates in
Caryocystites granatum, varies, so that some specimens possess more
superimposed plates than others, and even specimens with five
basal plates are not rare. According to the arrangement of the
plates, I do not think that Caryocystites and Echinospherites could
be separated. |

“A form nearly allied to Caryocystites granatum, observed by M.
Beyrich (Drift [Geschiebe] near Berlin), the plates of whose calyx
are more numerous, is distinguished by the bands which unite
the pores belonging to an entire series of pores, which penetrate
the entire thickness of the plates, so that the series of pores
appear also upon the inner surface of the plates... Something similar
may also be observed in many specimens of Caryocystites granatum,
inasmuch as the canals of the bands not unfrequently also exhibit
clefts here and there between the terminal pores. These clefts
may indeed be readily explained by the grinding down of the
canals; the occurence of the regular rows of pores in the species
above mentioned, however, leads us to question whether they always
have this origin.

“¢,. In Echinospherites aurantium and E. aranea every two pores of
two plates are not uncommonly connected by one, usually by two
canals, which are recognizable upon the outer surface of the plates ;
Echinospherites testudinarius, included by Von Buch in the ill-defined
genus Caryocystites, is an elongated Echinospherite. Its pore-
rhombs agree more closely with the previously-named species than
with Caryocystites granatum, though the number of the pore-canals
between every pair of pores is in some localities still greater.

* .... und dieser Canal ist immer ein einziger zwischen je zwei Poren, oder selbst
einer Porenreihe.

STRUCTURE OF THE CYSTIDE A. 45

In fact, we not unusually observe not only two, but three or even
four conjoined canals, which open at both ends into a pore, and
are so connected.

“qd. The genera Echino-encrinus, Pseudocrinites, Apvocystites, Pruno-
cystit's, are distinguished by possessing only a few pore-rhombs—
fragments of the system—which however are here justly termed
pore-rhombs. In Echino-encrinus angulosus and E. striatus there can
be no doubt that the elongated pores of these rhombs are clefts
which penetrate the whole thickness of the plates. Forbes remained
in doubt with regard to these pores, and was inclined to interpret
the ‘ pectinated rhombs’ as the situation of ciliary organs comparable
with the ciliated epaulettes of the larvee of Echini. Seeing the very
problematical nature of all pore-rhombs, and of all non-ambulacral
pores of the Crinoids in fact, the supposition that the cilia are
connected with the pores and pore-canals is not to be excluded.

“¢ The number of the pore-rhombs in the Echino-encrinites appears
to vary, and Echino-encrinus granatum, Volb., would appear to be
only such a variety of the E. angulosus.

“TJ. Cystideans with double pores upon the calycine plates,
which belong not to two different plates, but to the same. The
plates are facetted, and each facet possesses two closely approximated
pores. Here belongs a small group of Cystideans, which, since it
consists of many genera, might be called Diploporitide (Diploporiten).
The genera included in it are :—

“© 1. Spheronites pomum, His., type of a peculiar genus, which
may retain the name of Spheronites, as opposed to the Echinospherites
with pore-rhombs.

“2. Protocrinites (P. oviformis, Kichw.).

“3. Spheronites Leuchtenbergu, Volb., type of a peculiar genus,
which may be termed Glyptospherites. That the Russian Spheronites
pomum, Leuchtenb., or S. Leuchtenbergii, Volb., is not the Swedish
S. pomum, Volborth thought probable from Gyllenhal’s account.
The specimens of the Swedish form in the Mineralogical Museum
of this place put this beyond doubt. There are no calycine grooves
on the true Spheromtes pomum, His.; on the other hand, the five
outermost calycine plates are elevated into a triangular pyramid,
truncated at the mouth, as in Echinospherites aurantium; the edges
of the pyramid are broken off in all the specimens, and leave a doubt
as to the form of the arms which were probably present. The base
of the calyx is transversely truncated, and very broad in relation to
the diameter of the calyx ; it consists of six to seven pieces.

46 CANADIAN FOSSILS.

‘‘The relation of a few other Diploporitide to these genera is
still unknown. Many of the Cystideans described by Forbes,
and enumerated by him among the Caryocystites, viz. C. Litchit
(F.), C. pyriformis (F.), C. munitus (F.), do not belong to the
genus Caryocystites (von Buch), being rather Diploporitide allied
to: Spheronites pomum, which require further investigation.”

SECTION IIl.

DESCRIPTIONS OF THE LOWER SILURIAN SPECIES OF CYSTIDEZ OF
CANADA.

Genus PLEUROCYSTITES, Billings.
(Conadian Journal, vol. ii. p. 250, 1854; Geol. Survey of Canada, Report, 18517, p. 284.)

Generic Characters——Body, oval, flat; dorsal side composed of
large polygonal plates; ventral side almost entirely occupied by a
large oval space protected by an integument of numerous small
plates; arms or pinnule, free, two in number, articulated in two
series ; mouth, situated at.the base on the left side; a small aperture
near the apex; ambulacral orifice not yet observed; pectinated rhombs
three, one in the lower half of the body and two in the upper half;
column, short and tapering. Generic name from pleuron, a side.

The following is the arrangement of the plates:—The pelvic
or basal plates are four in number; the dorsal pair pentagonal, and
forming by their upper sloping sides a broad re-entering angle, in
which is supported a large hexagonal plate belonging to the next
series; the other two pelvic plates are situated one on each side of
the dorsal pair, and partly beneath them; they do not unite on the
ventral side to form the cup-shaped pelvis of the ordinary cystidee,
but spread out wing-like from the sides of the column; only a small
slender projection of these plates extends round so as to meet on the
ventral side. (Pl. i. fig. 1c.)

In the second series there are five plates; two of these are situated
at the lower outer angles of the body, and from their position in the
same level with pelvic plates, appear to belong to that series. They
are however the exact homologues of the two plates which support
the mouth in such genera as Echino-encrinites, Apiocystites, Glyptocys-
tites, and others of similar structure, but separated and thrust out of

CANADIAN FOSSILS. 47

their normal position by the introduction of the area of small plates.
The other three plates of the second series form a regular row across
the body above the pelvic plates. The central one is hexagonal,
it has one-half of the posterior pectinated rhombs on the right lower
side, and is flanked on each side by a large heptagonal plate.

The third series consists of four large plates, elongated vertically ;
one of these, situated on the right hand of the centre of the back, is
pentagonal, and next to it, on the left, is another of nearly the same
form, but made hexagonal by the truncation of one of the upper
angles. ‘These two plates are narrowed above to correspond with —
the decreasing dimensions of the body, which here begins to contract.
The other two plates of this series are either heptagonal or slightly
octagonal, and at their upper extremities they fold around the body
and unite on the ventral side by narrow projections, which arch over
the area of small plates. Above the third series are ten smaller
plates, which close the summit and form a solid support for the arms.

The ventral side, as before mentioned, is mostly occupied by an
area of small plates (see plate i. fig. 1c, and plate i. fig. 16) which
are altogether of a different character from those of the dorsal side.
They vary greatly in size in the different species; for instance, in
P. squamosus there are several hundreds of them, and in P. filitextus
only about forty or fifty. The margins of the dorsal plates being
folded over, form a solid smooth border around the whole space, and
to this border the small plates do not seem to be connected.
According to my view, the whole of the oval space on the ventral
side surrounded by the border, was covered by a flexible integument,
strengthened by the small plates, and these cannot therefore be
regarded as normal plates in the sense in which the term is used in
describing genera of Crinoids or Cystidea, but rather as the remains
of a partially calcified dermal covering for a part not protected by
the true skeleton. It follows that in this genus the dorsal side is
composed of a definite number of plates, arranged according to a
permanent plan, and in this respect is related to that group to which
Echino-encrinites belongs; while the ventral side, by the indefiniteness
of the number and arrangement of the plates, is more like the body
of a Spheeronite.

The mouth is situated on the left hand side of the base, and opens
out through a notch excavated in the border. In most specimens
the sutures between the plates cannot be detected in the border,
owing to the close manner in which they have been anchylosed. It
can be seen however, that if the two anterior basal plates were

48 CANADIAN FOSSILS.

folded round and brought up into their proper position, the mouth
would lie partly in the suture between two of the plates of the
second series, which is its position in many of the ordinary Cystidez
which have the definite number and arrangement of the plates.

The ambulacral orifice probably lies in the apex in the bottom of
the groove between the two arms, and must be exceedingly minute,
as I have been unable to detect it in several specimens that I have
disarticulated for that purpose.

The anal? aperture is also very small, and situated on the anterior
side, close to the apex. It consists of a small rugged notch in the
edges of two of the small plates, below the arms.

The arms are articulated in two series, and the ambulacral groove
is continuous from one to the other across the space between their
bases. On each side of the groove is a row of small marginal plates,
two or three to each joint of the arm.

The pectinated rhombs are three in number ; one of them is placed
half on the right dorsal basal plate and half on the large hexagonal
plate of the second series; the other two are also situated on the
dorsal side, one upon the left pair and the other on the right pair of
plates of the third series. Of these two rhombs the left one is the
larger in all the specimens I have seen.

This genus was first discovered in the Trenton limestone at the
city of Ottawa, and afterwards at Montreal in the same rock. In
1856 Mr. Richardson found one species in the Hudson River group
at Anticosti. In the Museum of Practical Geology, Jermyn Street,
London, are specimens of a species, P. Rugeri (Salter), collected in
the Caradoc formation of Wales; and M. Barrande informs me that
a species, which appears to be referable to the genus, cccurs in his
Etage D, in Bohemia, the equivalent of the Landeilo and Caradoc
of Britain, and of the Trenton and Hudson River groups of America.

The species are so closely allied, that there is much difficulty in
defining them; yet I am satisfied that there are several which are
distinct. It is very improbable that a genus of Cystideans, ranging
from the Chazy limestone to the Hudson River group, and spreading
over so vast a geographical area as that which lies between Canada
West and Bohemia, should have but one species. Still it is not
easy to find many good specific characters to separate those in the
collection at Montreal. The following appear to me to be distinct;
but when the genus becomes better known, it may be necessary to
make some other disposition of them :—

CANADIAN FOSSILS. 49

J. PLEUROCYSTITES SQuAMmosuS, Billings.

Plate I. Figures la, 16, 1c, 1d.
(Canadian Journal, vol. ii. p. 251, 1854; Geol. Survey of Canada, Report, 1856, p. 286.)

Description.—In this species the large plates on the dorsal side are
smooth, or but slightly marked with obscure radiating and concentric
ridges, and the opening on the anterior side is protected by an
integument composed of a vast number of small, mostly hexagonal
plates, each less than the fiftieth part of an inch in diameter near
the border, and about the twentieth of an inch in the centre of the
space. The rhombs are small and somewhat elliptical,*the larger
axes of the upper two being transverse to the length of the fossil;
in a specimen with a body thirteen lines in length the left upper
rhomb has a transverse axis of three lines and a vertical axis of two
lines in length. The rhomb on the right is two lines long and one
and a-half broad; the basal rhomb is about of the same size as the
last mentioned; they are all slightly elevated above the general
surface, and either flat or only a very little concave. The pores
extend completely across the rhomb from one side to the other.
The column is strongly annulated, and the projecting joints or rings
striated vertically, so that when well preserved they have a nodulose
appearance.

EXPLANATION OF Figures. Plate I.

Figs. la and 1b. Dorsal views of two specimens.

Fig. 1c. Ventral view of a specimen shewing the plated integument and’strong borders
formed by the folding over of the dorsal plates ; the mouth is at o.

Fig. 1d. Ventral view of the upper part of the cup and arms of a specimen of this
species, the remainder of which is completely buried in the stone; le is
the same enlarged ; at a is the small sub-apical aperture. It is represented
too large in the figure.

Locality and Formation.—Trenton limestone, near the middle of the
formation at Ottawa.
Collectors.—E. Billings, J. Richardson.

IJ. PLEvROCYSTITES ROBUSTUS, Billings.

Plate I. Fig. 2a.
(Canadian Journal, vol. ii. p. 252, 1854; Geol. Survey of Canada, Report, 1856, p. 286.)

Description.—In this species the rhombs are obscurely elliptical,
or rather in the shape of a spherical triangle; they have somewhat
the appearance of a rhomboid, but then the angles are so much.

D

50 _ CANADIAN FOSSILS.

rounded that an elliptical figure is approached, which owing to the
slight curvature of the upper side, is also triangular. They very
much resemble the rhombs of P. squamosus, but have a concave instead
of a plane surface, as in that species; they are surrounded by an
elevated rounded border. The surface of the plates upon the dorsal
side is ornamented with fine rounded radiating striz, which are
always at right angles to the margin of the plates. In addition to
the small striz on some of the plates, an obscure ridge runs from
each of the angles towards the centre of the plate.

This species unly differs from P. squamosus, as far as can be ascer-
tained from the few fragments collected, in the form of the rhombs
and striation of the surface ; it appears also to have been a larger and
more vigorous species. It is very difficult to decide whether it be
really distinct from the other or not.

Length of the upper left rhomb, three lines and a-half; breadth
in the vertical direction, three lines; the right rhomb is somewhat
smaller.

EXPLANATION OF Figure. Plate I.

Fig. 2a. Shews a fragment of the upper part of a specimen. From the position in
which the artist viewed the specimen, the left rhomb in the figure appears
too angular on the upper side.

Locality and Formation—tTrenton limestone, City of Ottawa.
Collector.—K. Billings.

III. PLEUROCYSTITES FILITEXTUS, Billings.

Plate II. Figs. la, 10.
(Canadian Journal, vol. ii. p. 252, 1854; Geol. Survey of Canada, Report, 1856, p. 286.)

Description—The pectinated rhombs of this species are of a very
different shape from that of the same organs in P. squamosus and
P. robustus. They have their greatest length in the vertical direction
instead of the transverse, as in the other species. In the structure of
the integument of the ventral side there is also a difference, which
cannot but be of specific importance. The plates (see pl. ii. fig. 1b)
are ten times the size, and consequently greatly less in number. The
surface of the dorsal side of the specimen figured is marked by strong
ridges radiating from the centre to the angles of the plates. Two
fasicles of coarse rounded ridges, five in each, proceed from the centre
of the large hexagonal plate of the second series on to the two
central plates of the third series, crossing the sutures at right angles.

CANADIAN FOSSILS, 51

Similar ridges, but fewer in number, cross the sutures between the
other plates at right angles. In some of the specimens there are
pretty strong concentric lines interwoven with the others, and portions
of the surface, especially where there is no striation, are roughened
by the presence of small irregular tubercles. In other specimens
the whole of the surface appears to have been striated at right angles
to the sutures, and it is quite certain that in all the species of this
genus there was more or less variation in the character of the striation.

Length of the upper left rhomb, five lines in a specimen fourteen
lines long; of the right rhomb, three lines. The form of the
basal rhomb has not yet been precisely ascertained, but appears to
be of an elliptical shape, its greatest length lying in the direction of
the suture upon which it is placed.

EXPLANATION OF Figures. Plate II.

Fig. la is a specimen which has the column and a portion of the arms firmly attached
to a piece of limestone. The greater part of the body however is loose, and
can be removed in one piece, giving a view of the ventral side. Fig. 10 is
the ventral side, shewing the large plates of the integument, and obscurely
the small aperture near the apex. The specimen is somewhat distorted by
pressure, so that the true form of the rhombs cannot be made out. 0, the
mouth.

Locality and Formation—Trenton limestone, City of Ottawa. In
one locality the surface of a bed of limestone for several yards square
was covered with the separated plates and joints of the columns of
this species. The highly instructive and valuable specimen figured
is the most perfect that has been found.

Collector.—K. Billings.

IV. PLEUROCYSTITES ELEGANS, Billings.

Plate II. Figs. 2a, 26, 2c, 2d.
(Geological Survey of Canada, Report, 1856, p. 287.)

Description.—This species much resembles P. filitextus, but may be
readily distinguished by the rhombs being shorter, and by the much
stronger striation, in proportion to the size, over its whole surface.
The rhombs have a more regular outline than those of P. squamosus
or P.robustus; they are bounded by four nearly straight sides, instead
of curved lines; the poriferous areas are however somewhat rounded
at the upper angles, while the form of the border 1s such as to give
to the whole organ a regularly rhomboidal aspect. The shape is
best shewn in fig. 2a, and in the basal rhomb of 2c; by comparing

52 CANADIAN FOSSILS.

the latter with the portion of the basal rhomb of P. fiitextus, repre-
sented in 1a, the difference will be at once detected; all the others
are more or less distorted. In P. filitertus the left upper rhomb is a
little more than one-third the length of the body, but in P. elegans
it is a little more than one-fourth. The plates of the ventral side
have not yet been seen.

EXPLANATION OF Ficures. Plate II.

Figs. 2a, 2b, 2c and 2d? are dorsal views of this species. It is doubtful whether 2d
should be referred to this species or to the thickly striated varieties of
P. filitextus. The crushed condition of this, and indeed of all the specimens,
renders it most difficult to decide when the species are so closely allied.

Locality and Formation.—Trenton limestone, City of Ottawa.
Collector.—E. Billings.

V. PLEUROCYSTITES EXORNATUS, Billings.

Description—Rhombs sub-triangular, surrounded by a thin sharp
border, which is a good deal elevated above the surface. The upper
side of the rhomb is nearly straight, and the other two sides converge
to a slightly rounded angle below. The outline of the rhombs of
this species is like that of P. robustus ; but, on the other hand, the
poriferous area or portion has a flat surface, while in the other species
it is concave. The plates of the ventral integument are about the
size of those of P. fliteztus, from which species it differs by the form
cf the rhombs; the size of the ventral plates also separates it from
P. squamosus. The column is beautifully striated longitudinally.

Locality and Formation—Lower part of the Trenton limestone,
Montreal. Fragments resembling this species occur in the Chazy
limestone near Montreal.

Collector.—E. Billings.

VI. PLEUROCYSTITES ANTICOSTIENSIS, Billings.

Plate I. Figure 3.
(Geological Survey of Canada, Report, 1856, p. 288.)

Description.—All that can be said about this species is that the
rhombs are very long and narrow, and the large joints of the column
so coarsely striated that they appear to be nodulose. Only a frag-
ment, consisting of a portion of the column and the lower part of
the body, has been collected; the specimen measures eleven lines

CANADIAN FOSSILS. 53

from the base of the body to the upper angle of the large dorsal
hexagonal plate, and the right half of the left upper rhomb is in
length five lines and in breadth one line. The plates appear to have
been smooth, and in this respect principally does the species differ
from P. filitextus, which is much ornamented with radiating strie.
This is the only species we have as yet from the Hudson River group.

EXPLANATION OF Figure. Plate I.

Figure 3. Dorsal view of an imperfect specimen of this species.

Locality and Formation.—Charleton Point, Island of sn icostt
Hudson River group.
Collector.—J. Richardson.

Genus GLYPTOCYSTITES, Billings.
(Canadian Journal, vol. ii. p. 215, 1854; Geol. Survey of Canada, Report, 1856, p. 280.)

Generic Characters—Body, elongate, cylindrical; test composed
of four series of plates, of which there are four in the basal, and
five in each of the second, third and fourth series; three of the basal
plates are pentagonal, the fourth hexagonal; the mouth, in the only
species in which it has been seen, is situated in the lower half of the
body, its lower side being formed of a notch in that plate of the
second series which rests upon the hexagonal basal plate; it is
without a valvular apparatus; the ambulacral orifice is in or near
the centre of the summit, where it receives the five ambulacral
grooves of the arms; near it is a small anal? pore; there are from
ten to thirteen pectinated rhombs; the arms are recumbent, and
upon the apex of the fossil the ambulacral grooves are beset with
small marginal plates; the pinnule are articulated in two series;
the column is short, and tapering to a point at the lower extremity.

The plates of the cup of this genus are somewhat remarkable for
their form. In the hitherto known Crinoidez and Cystidew they
are polygonal and bounded by straight sides; but all the species of
this genus yet observed have some of them with re-entering angles.
By referring to pl. ili. fig. 1a, it will be seen that the basal series of
G. multiporus is very regular, and exactly like that of the genus
Echino-encrimtes (Volborth), represented in fig. 16, the only difference
being that the dorsal plate is so much extended upwards as to
separate two of the plates of the second series. These two plates
are notched on the upper side for the reception of the small
hexagonal plate of the third series. Several of the other plates are

54 CANADIAN FOSSILS.

also variously notched. In the species G. Logam, G. Forbesi, and
G. gracilis, many of the plates have re-entering angles, but in their
arrangement in the walls of the cup they form regular series.

The pectinated rhombs also exhibit some peculiar new features.
In no other genus have more than three been observed, and these,
in all the genera except Echino-encrimites, are placed one at the base
of the dorsal side and two in the upper half of the body, as in the
genus Pleurocystites. The surface of Glyptocystites shews that three
is not the constant number. It was also supposed to be essential to
these organs that each should occupy two contiguous plates, about
half of the rhomb being upon one and the other half upon the other.
In Glyptocystites we have the new character of-half rhombs in all the
four species. Generic name from glyptos, sculptured.

Glyptocystites at one time appeared to me to be so closely related
to Echino-encrinites, that I had much doubt as to the propriety of
retaining the name. After having examined a number of good
specimens of the Russian genus, in the Museum of Practical Geology,
London, I am satisfied that there is no generic affinity between them,
except in the presence of the two rhombs in the dorsal side of the
base. In no other respect is there any near relationship. That the
number and arrangement of the plates are the same in both genera,
is not a character sufficient to unite them; otherwise we should be
obliged to make but one genus of Pseudocrinites (Pearce), Apiocystites
(Forbes), Prunocystites (Forbes), Echino-encrinites (Volborth), Lepado-
crinites (Conrad), and Glyptocystites. In all of these there are four
series of plates, as follows: Four basal plates, and five in each of
the second, third and fourth series. If we seek for other characters,
we find that the Russian genus consists of several species, which,
taken together, constitute a group having in its general aspect no
resemblance whatever to that group formed by the four species of
the American genus. The European species have short angular
bodies covered with thick plates, the ventral side sometimes greatly
projecting, and only three pectinated rhombs obscurely developed ;
while all the species of our genus have elongated sub-cylindrical
bodies, nearly covered with rhombs, some of them of a large size.

VII. GuyprocystiTes MULTIPORUS, Billings.

Plate II.
(Canadian Journal, vol. ii. p. 215, 1854; Geol. Survey of Canada, Report, 1856, p. 281.)

Description—One inch in length, five lines in diameter, cylindrical,

CANADIAN FOSSILS. 55

obscurely five-sided, rounded at the apex, abruptly truncated at the
base ; mouth large, oval, without valves, situated with its upper
margin about the centre of the length of the body; ambulacral
orifice small, situated in the centre of the apex, a small pore near it
on the right hand side; arms five, four of them extending down the
sides to the base, the fifth only two or three lines in length;
thirteen pectinated rhombs; column short, tapering to a point,
annulated by alternately wide and narrow joints, the former of
which are striated on their projecting edges in the longitudinal
direction.

In this species the basal and second series of plates are pretty
regular, but the third series ‘contains two plates, which are very
small in proportion to the others, an irregularity compensated by a
corresponding enlargement of two of the plates of the fourth series,
which are of so great a size that they extend from the top of the
body down to the second series, and thus fill up the blank in the
third series formed by the deficiency in the size of the two small
plates mentioned (see pl. iii. fig. 1a). The whole of the upper half
of the test presents very little of order in its structure, in consequence
of this disproportion in the size of the plates.

The distribution of the pectinated rhombs is as follows :—

On the anterior side there are two rhombs, a small one just below
the mouth on the right side and a large one above, which extends
from the mouth nearly to the apex (see pl. iii. fig. d).

On the right side there are two; a small one near the apex and a
large one below it, but still nearly altogether in the upper half of
the fossil. Both of these are a little oblique, the large one with its
upper extremity leaning forward, and the small one leaning back-
ward (see pl. ii. fig. c).

On the posterior or dorsal side there are four, two at the base,
one-half of each being on the basal plate of this side, and the other
half on the contiguous plate of the second series; a third very small
rhomb is situated between the two small plates of the third series,
and a fourth very large one is divided between the two large plates
of the fourth series in the upper half of the fossil (see pl. iii. fig. F).

On the left side there are five, a large one next the mouth, and at
itsgupper angle another, which extends across the sides, sloping a
little downwards, with a third which rises nearly perpendicularly
from the posterior angle of the second one; below this there is a
half-rhomb, and above the large one first mentioned in this division
a very small rhomb, only seen in perfect specimens (see pl. ili. fig. E).

56 CANADIAN FOSSILS.

There is very little difference in the form of the rhombs. They
have each, except the three smallest, a smooth space in the centre,
which is a little elevated above the poriferous surface, and the pores
are elongated clefts which pass under the central smooth place, so
that the pores of the one side are continuous with those upon the
other. The thin partitions between the pores penetrate some dis-
tance into the interior of the fossil. Figures g and &, plate iii. are
sections made through a specimen to shew this character. In nearly
all the rhombs one side of the smooth central space has an elevated
border.

The arms are five in number, four of them extending down the
sides from the apex to the base; the fifth is a short arm, and reaches
only two or three lines from the summit on the left side (see pl. iii.
fig. E). They are composed of double series of joints alternating
with each other, and so loosely attached to the surface that they can
be easily removed with the point of a sharp knife. The ambulacral
grooves extend the whole length of the arms, and have on each side
a row of seven or eight pinnule, those upon one side alternating
with those on the other. The two anterior arms unite a short
distance above the large rhomb, which is situated over the mouth
(see figs. a and n) ; their two ambulacral grooves then form but one,
and cross the apex to the posterior side (see fig. ¢), where they divide
and run down the posterior pair of arms. In crossing the summit
the groove sends out a branch to the short arm, and, throughout
their length, small branches to the pinnule.

The ambulacral orifice is very small, and situated in the bottom
of the groove, a little on the anterior side of that point where the
groove from the short arm enters the main apical furrow. This
aperture is usually concealed by the small marginal plates of the
ambulacra shewn in fig. g. Of these there is a row on each side of
the groove, and when the top of the fossil is so perfect as to exhibit
them well-preserved, they are always so firmly interlocked that they
completely close the furrow. In this state they no doubt formed a
securely protected covered way for the passage of the ambulacral
vessels to the arms.

The minute aperture on the left side of the apex, near the ambu-
lacral orifice, is a minute pore situated in the centre of a smgll
rounded tubercle (see fig. g).

The pinnule are scarcely one-third of a line in diameter, and
about half-an-inch in length. They are articulated in two series.

CANADIAN FOSSILS. 57

EXPLANATION OF Ficures. Plate III.

Fig. la. The plates of the calyx spread out; the dotted lines which extend from the top
to the bottom indicate the course of the arms.
Fig. 1b. Plates of the genus Echino-encrinites figured here for comparison.

Fig. d. Anterior view of a perfect specimen of G. multiporus.
Fig. E. The left side of the same specimen.

Fig. F. The dorsal or posterior side of another specimen.
Fig.c. The right side.

Fig. g. The apex enlarged.

Fig. i. The base.

Fig.n. A specimen with the column attached, anterior view.
Fig. L. One of the rhombs enlarged.

Figs.g & k. Sections shewing the depth to which the partitions of the rhombs entered.

Locality and Formation— Trenton limestone, City of Ottawa,
Montreal and Beauport. Only fragments have been found at the
latter two places, and all the perfect specimens, about sixty, were
collected from a piece of shale about two yards square and one or
two inches in thickness. There is good reason to believe that they
lived and died upon this spot. The shale was a layer between two
beds of limestone, the lower of which was partly composed of the
detached plates of this species. Imbedded in its surface were several
perfect specimens among the fragments. The shale which covered
it was full of individuals with their columns and delicate pinnulz
attached. It is quite clear that they could not have been at all
drifted about the bottom after death, otherwise they would at least
have lost their columns and pinnule. It is more probable that they
formed a little colony, growing on this spot at a considerable depth,
and in clear water, and that the shale consists of a deposit showered
down upon them from a superficial current, literally burying them
alive.

Collector.—E. Billings.

VIII. Guyrrocystires Logant, Billings.
Plate IV. Figs. la-h.

(Geological Survey of Canada, Report, 1856, p. 282.)

Description—tLength of large specimens one inch and a-fourth ;
diameter eight lines; cylindrical, obscurely five-sided, abruptly trun-
cated at the summit; base slightly rounded ; each plate ornamented
with from three to seven exceedingly elevated, somewhat thin, sharp
ridges, which radiate from the centre to the sides; spaces between
the ridges smooth, or very minutely striated concentrically ; calycinal

58 CANADIAN FOSSILS.

ambulacral grooves, to the angles of the truncated apex, bordered
by marginal plates, as in G. multiporus, and furnished near their
extremities each with several smaller free arms, or stout pinnule,
articulated in two series; there are about twelve or fifteen pectinated
rhombs, each with a smooth central area, which is not elevated
above the surface of the pores, but is quite flat, a character which
Separates this species from the next.

Neither the mouth nor the ambulacral orifice has been observed,
owing to the imperfection of the specimens.

The column is short, strongly annulated, and tapering to a point
at its lower extremity. The small joints are pentagonal, and present
a very remarkable character in the fact, that their angles form five
spiral lines round the column throughout its length. The large
joints which constitute the annulations of the column appear to be
circular ; but none of the specimens are sufficiently well-preserved
to shew clearly that they are so.

The pinnule are furnished on their ventral sides with minute
marginal plates, similar to those of Plewrocystites. This appears to
be one of those species in which the body of the arm was never
developed, but only the grooves and pinnule.

The detached plates of this magnificent species can be readily
distinguished from those of any other crinoid or cystidean of the
Trenton limestone by the peculiar star-like appearance produced by
the very elevated, sharp, and thin radiating ridges with which their
surfaces are ornamented. Although a number of the bodies, many
of them with the column attached, have been collected, yet none of
them shew clearly that side upon which the mouth is situated.
The plates are more regularly alternating than in G. multiporus.
This species cannot be identified with the Echino-encrinites anatina-
forms figured by Professor Hall in plate xxix. vol. i. Paleontology of
New York. By referring to that work it will be seen, that the
triangular spaces upon the plates between the large radiating ridges
are strongly striated at right angles to the sides of the plates (see
the two figures, 4d and also 4g, in the plate cited). In our species
these spaces are quite smooth, or only marked by faint lines, which
are concentric, and therefore run in a direction at right angles to
that of the striz of the New York specimens. Professor Hall’s
figures do not exhibit any pectinated rhombs; and further, by figure
4c it is shewn that the base of E. anatinaformis is composed of two
pentagonal and two quadrangular plates; ours has three pentagonal
and one hexagonal basal plate.

CANADIAN FOSSILS. 59

EXPLANATION OF Figures. Plate IV.

Figs. la and 16 are dorsal views of two specimens.

Figs. lc, 1d and le are enlarged views of the interiors of three rhombiferous plates,
shewing that the pores penetrate through, and that each on the inside is
surrounded by an exceedingly thin elevated border.

Fig. 1f. A portion of the ambulacral groove of the apex, and one of the pinnule
enlarged.

Fig. lg. A fragment with two of the pinnule.

Figs. li and 1j. Fragments of columns; the specimens are crushed, and do not clearly
shew the spiral arrangement.

Locality and Formation—tTrenton limestone, Island of Montreal ;
plates in an excellent state of preservation are extremely abundant
in certain localities of the formation.

Collectors.—Sir W. KE. Logan, E. Billings.

I beg to dedicate this species to the discoverer.

VIII. Giyprocystires LoGanr var. GRACILIS, Billings.
Plate IV. Fig. 2.

Description—This species or variety differs from the last im its
greater proportional length and form of the rhombs and column.
There is a deep angular furrow around the margin of each rhomb,
and the central space, instead of being quite level, is much elevated.
In the only specimen collected there is no unperforated area in the
centre of the rhomb, as in G. Logani proper. The large joints of
the column are close together, whereas in the other form they are
separated by an interval equal to or greater than their thickness.
On account of these differences, 1 have thought it proper to name
this form as a variety of G. Logani.

Locality and Formation.—Trenton limestone, Montreal.

Collector.—Sir W. HK. Logan.

IX. GuyprocystirEs Forsest, Billings.
Plate IV. Fig. 3.

(Geological Survey of Canada, Report, 1856, p. 283.)

Description.—The body of this species, judging from the fragments
in the collection, is about two inches in length and three-fourths of
an inch in diameter. The character of its surface is such, that
detached plates may be distinguished at a glance from those of
either of the two preceding species, being larger, thicker, and more

60 CANADIAN FOSSILS.

profusely ornamented with radiating ridges and striz. Although
there is an abundance of the pees remains in the Chazy
limestone, yet only the base of the cup of one specimen has been
found. Fortunately it is sufficiently well-preserved to shew that at
least a great proportion of the numerous plates and columns with
which it was associated belong to the same species. The specimen
consists of four joints of the columns, two of the basal plates on'the:
dorsal side, one large heptagonal plate of the second series, and
portions of two others, one on each side of this latter. The follow-
ing figure shows the disposition of the rhombs at the base of the
dorsal side :—

At the base upon the dorsal side there are two perfect rhombs,
one-half of each of which is on the central basal plate ; the other two
halves are upon the two plates of the second series, which rest upon
the upper sloping sides of this basal plate. These two rhombs
therefore correspond to the pair occupying the same position in
Echino-encrinites angulosus, Volborth (see pl. iii. fig. 16), and G. mul-
taporus, pl. iii. fig. 1a. In addition however, we have in G. Forbesi
two nena on two of the basal plates which do not occur in ©
the other species; their positions are shewn in the above wood-cut.

The plates have two sets of surface ridges :—

1. From four to six large ridges, which radiate from the centre
of each plate to the centre of each straight side of the plate. They
are in general strongly elevated, with rounded or sharp edges and
broad bases. In the angular spaces formed by the large ridges
are smaller parallel ones. which form other included similar angular
spaces (see plate iii. figs. 3e and 3/).

2. The whole surface of the plates is also covered with sharp
concentric striz, which are, on some of the plates, stronger between
the ridges than upon them (see plate iv. figs. 3e and 3f).. When the
plates are worn, the large radiating ridges become rounded, and the
concentric striz are wholly obliterated.

The joints of the column attached to the fragment figured appear
to be obscurely pentagonal; but in the same rock are many columns

CANADIAN FOSSILS. 61

which are round, and with the large joints ornamented with little
pits or coarse strie. It is not certain that these round columns
belong to the same species.

EXPLANATION oF Figures. Plate IV.

Figs. 3a and 3b. Two views of the base of a specimen.

Figs. 3c and 3d. Imperfect plates, to shew the character of the rhombs. 3d has the
remains of four rhombs ; 3e is the basal plate of the right side ; 3f the
hexagonal basal plate of the anterior side; 3g and 34 round columns,
with the edges of the large joints pitted.

Locality and Formation —Chazy limestone at Caughnawaga, and
on the Island of Montreal.
Collectors.—Sir W. KE. Logan, J. Richardson, E. Billings.

Genus COMAROCYSTITES, Billings.
(Canadian Journal, vol. ii. p. 269; Geological Survey of Canada, Report, 1856, p. 288.)

Generic Characters.—Body, ovate, the smaller extremity being the
base; pelvis, small, of three plates, above which are from eight to
eleven irregular rows of plates, mostly hexagonal ; mouth, near the
summit, provided with a valvular apparatus; arms, free, grooved,
and composed of a single series of joints bearing pinnule ; ambula-
cral orifice in the apex between the arms; column, round and smooth.
The plates of the only species that has been collected present, in
some conditions of preservation, a peculiar vescicular structure of
their exterior surfaces, while sometimes they are solid and smooth.
Generic name, comaron, a strawberry.

X. COMAROCYSTITES PUNCTATUS, Billings.

Plate V.

(Canadian Journal, vol. ii. p. 270; Geological Survey of Canada, Report, 1856, p. 288.)

Description—The body of this species is of an oval or pyriform
shape, and in large specimens about one inch and a-half in length.
It is protected by plates which have a deep concavity, occupying
nearly the whole of the area of each, the effect of which is to cover
the surface of the fossil with large rounded pits, an aspect that serves
to distinguish it at the first glance from any other known in the
Lower Silurian rocks of Canada. In certain states of preservation
the sutures are marked by minute thickly-set square or oblong rough
punctuations, which do not however appear to penetrate through to
the interior. In some specimens there is only one, and in others

62 CANADIAN FOSSILS.

two or three rows of these punctures upon each suture. The greater
portion of the area of the plate is marked with deep fissure-like striae
at right angles to the suture, and with thin erect lamellz or partitions
between them. These are sometimes crossed by other lamelle
parallel with the edges of the plates, the effect of which is to
produce a peculiarly rough surface. Sometimes none of these are
visible, and the surfaces of the plates are then uniformly smooth and
solid. These variations are the results both of weathering and
structure. Portions of the centres of the plates of the two specimens
figured (pl. v. figs. 1 and 2) have the external surface smooth, while
the margins are rough.

The mouth is large, near the apex, and closed by a pyramid of
five triangular valves.

The ambulacral orifice has not yet been distinctly observed, but
there can be little doubt of its existence. The arms are four in
number, and consist of an anterior pair situated directly over the
mouth, and a posterior pair placed opposite, on the posterior side of
the summit; a deep narrow groove crosses the apex, in a direction
from the anterior to the posterior side; from one end it sends up
two branches into the anterior pair of arms, and from the other end
two into the posterior pair. The arrangement of the ambulacral
furrows in this species is then precisely as in Glyptocystites multiporus,
and no doubt an orifice will yet be found in the bottom of the
groove, upon the summit between the two pairs of arms. The arms
consist of a single series of joints, each about one line and a-half in
length; the pinnule are nearly cylindrical, and divided by joints at
lengths of about half a line. In the only specimen known with the
arms attached (plate v. fig. 1) one side of the arm only can be seen,
the other being imbedded in the rock. It shews that upon at least
the side exposed there is one pinnula to each joint, but whether
there is a row on the other side of the groove or not remains to be
ascertained.

The column is round and smooth, formed of very thin joints, and
does not, in a specimen with three inches preserved, exhibit any
signs of tapering.

EXPLANATION OF FicurEs. Plate V.

Fig. 1. Anterior view of a large specimen, with one arm and the pinnule attached.
o, the mouth; la, a plate of the same enlarged, to shew the peculiar stria-
tion; 1b, the valvular apparatus of the mouth enlarged.

Fig. 2. View of the left side of another specimen; 2a, a plate of same enlarged ;

2b, outline of the summit, shewing the positions of the bases of the arms,
and the ambulacral groove between them.

CANADIAN FOSSILS. 63

Locality and Formation —Trenton limestone, City of Ottawa.
Fragments are not very uncommon, but perfect specimens exceed-
ingly rare. :

Collectors.—K. Billings, J. Richardson, and others. The specimen
fig. 2 was found by Captain W. S. Hunter of Ottawa, and fig. 1 by
E. Billings.

Genus AMYGDALOCYSTITES, Billings.
(Canadian Journal, vol. ii. p. 270, 1854; Geol. Survey of Canada, Report, 1856, p. 288.)

Generic Characters.—Body, ovate; pelvis of three plates, above
which are eight or more irregular rows of plates; the mouth is
near the summit, closed by a valvular apparatus; arms, large,
recumbent, composed of a double series of joints bearing a single
row of pinnulz ; ambulacral orifice situated in the apex ; ambulacral
groove not in the centre of the upper surface of the arm, but on one
side ; column round; the plates are solid, or not poriferous. Generic
name from amygdale, an almond.

Comarocystites' differs from this genus by the possession of free arms
and the porous character of its plates.

XI. AMYGDALOCYSTITES FLOREALIS, Billings.
Plate VI. Fig. 1a—le.
(Canadian Journal, vol. ii. p. 270, 1854; Geol. Survey of Canada, Report, 1856, p. 289.)

Description.—Body ovate, rounded at the apex, tapering towards
the base, about one inch and a-half in length. Each of the plates of
_ this species has a low rounded tubercle in the centre, from which
ridges radiate to the angles; these ridges are scarcely elevated above
the surface where they leave the border of the tubercle in the centre,
but increase in width and height as they depart from it; they are
sharp-edged, and attain their greatest height at the angles of the
plates. The arm crosses the summit, and extends nearly down
to the base upon one side, and only two or three lines from the
apex on the other; it is composed of a series of large joints,
which are about one line in height and scarcely so much in width,
and a second series of smaller pieces about one-half the height which
are placed at the bottom of the larger, upon one side. The arm
chus composed forms a projecting ridge up the posterior side of the
body across the apex, and a short distance down the anterior side.

64 CANADIAN FOSSILS.

Each one of the large joints bears a pinnula, and the ambulacral
groove is situated not on the top of the arm, but on one side.
On the posterior side of the fossil the groove is on the left side of
the arm. On the apex there appears to be an interruption, as if
one of the joints were absent; the ambulacral orifice is no doubt
situated at this point, but it has not been clearly made out in any
of the specimens yet procured. From this supposed position of the
ambulacral orifice proceeding forward the groove is on the right
side of the arm, the mouth being on the left, as shewn in plate vi.
fig. 1a, at m.

The column is round, smooth, and composed of thin joints.

In this interesting form we have an example of a Cystidean with
a body composed of an indefinite number of plates, like the Sphero-
nites, and with the arms arranged exactly as they are in Pseudocrinites,
a genus characterised by a few plates which are definite in number.

EXPLANATION OF Figures. Plate VI.

Fig. la. The left side of a specimen; m, the mouth. Fig. 1b. Right side of the same.
lc, posterior ; and ld, anterior views. The groove is not clearly shown in
this specimen. le, one of the plates enlarged.

Locality and Formation—tTrenton limestone, City of Ottawa.
Collector.—E. Billings.

XII. AMYGDALOCYSTITES TENUISTRIATUS, Billings.

Plate VI. Figs. 2a-2f
(Canadian Journal, vol. ii. p. 271, 1854; Geol. Survey of Canada, Report, 1856, p. 289.)

Description.—Body elongate, ovate ; plates smooth in the centre ;
a low rounded ridge proceeds from the smooth space in the centre
of each plate to each of the angles, where it meets the similar
ridges which radiate from the centres of the adjoining plates ;
between these ridges the triangular spaces are finely but very
distinctly striated at right angles to the sutures. The mouth is
close to the arm on the left side, near the summit.

The specimen represented by figs. 2a and 26 is the one upon
which I drew up the original description published in the Canadian
Journal in 1854. It shews only fragments of the arm, and the
surface of the plates is so different from that of A. florealis, that I
then had no doubt of the distinctness of the two species. Last
summer, however, I found at Belleville, Canada West, the other
specimen, fig. 2c, which has much the form of A. florealis, and the

CANADIAN FOSSILS. 65

arm almost precisely the same, but the plates are striated like those
of A. tenuistriatus. It seems to connect the two species, but until
good clear specimens can be examined, it would be the better plan
to retain the two names.

EXPLANATION oF Figures. Plate VI.

Figs. 2a, 2b. Right and left side of the Ottawa specimen; m, the mouth. 2c. Left side
of specimen from Belleville, shewing a portion of the arm. 2e. The arm en-
larged, shewing the ambulacral groove. 2f. View of the top of the arm,
shewing the articulating cavities of the pinnule, and the branches of the
ambulacral grooves leading to them. 2d. A plate enlarged, shewing the
striz.

Locality and Formation —Trenton limestone: one specimen from
the city of Ottawa and one from Belleville. The species appears to
be excessively rare.

Collector.—E. Billings.

XIII. AMYGDALOCYSTITES RADIATUS, Billings.

Plate VI. Figs. 3a, 30.

(Canadian Journal, vol. ii. p. 271, 1854; Geol. Survey of Canada, Report, 1856, p. 289.)

Description —Body ovate; plates somewhat convex, and orna-
mented with strong ridges which radiate from the centres to the
angles; mouth ambulacral orifice and arms, unknown; column
round smooth composed of thin joints.

The spaces between the large radiating ridges are flat and covered
with small tubercles, which disappear when the plates are a little
worn.

Of this fine and very distinct species, enough has not yet been
found to shew conclusively that it belongs to the present genus. The
plates however are solid, or not poriferous, and the shape of the
body and column is so much like the other species, in general
aspect, that I have referred it to this genus for the present.

EXPLANATION oF Figures. Plate VI.

Fig. 3a. A specimen crushed flat. 3b. One of the plates enlarged. The specimen is
worn, and does not shew the granular surface of the spaces between the
radiating ridges.

Locality and Formation.—Trenton limestone, City of Ottawa.
Collector.—K. Billings.

66 CANADIAN FOSSILS.

Genus MauocystitEs, Billings.

Generic Characters.—Body ovate or globular, composed of an
indefinite number of plates, usually about forty or fifty; mouth,
almost apical; ambulacral orifice on one side, but in the upper half
of the body; arms recumbent, in some species numerous; plates
thick solid, not poriferous; column unknown. Generic name from
malum, an apple.

This genus is composed of some species of Cystideans lately
discovered in the Chazy limestone. They are usually globular, and
covered with smvoth plates, and in general form and aspect much
resemble the Echinospherites of Scandinavia and Russia, from all of
which however they differ in the absence of pores in their plates.

The genus Cryptocrinites (Von Buch) is related: to Malocystites so
far as regards the absence of pores or pectinated rhombs, but differs
in having the ambulaeral orifice in the apex, the mouth being in the
side, and appears to be composed of a definite number of plates, there
being three in the basal series, five in the second series, and alter-
nating with these, five others in the second series.

Malocystites differs from Amygdalocystites in being composed of a
lesser number of plates, and in having the ambulacral orifice in the
side, and the mouth nearly in the centre of the apex. The arms
appear also not to be alike in the two genera, although none of
the specimens are sufficiently well-preserved to shew the structure
very distinctly.

XIV. Marocysrires Murcuisoni, Billings.
Plate VII. Figs. la—1v.

Description—Body globular, or slightly ovate; plates varying
from plane to convex, covered with small granular tubercles; arms
usually eight, forming two fascicles of four in each, connected by a
short groove, in the bottom of which is the ambulacral orifice ;
they are long, and wind around the body obliquely descending from
the orifice nearly to the base; mouth nearly circular, without valves.
In a specimen eleven lines long and ten lines in greatest breadth
the ambulacral orifice is half a line broad, and the mouth one line
and a half. The area of the mouth is therefore about nine times
creater than that of the ambulacral orifice.

CANADIAN FOSSILS. 67

This species presents some variations in form and size. The
greater number of the specimens are nearly globular, and about one
inch in diameter. Fig. 1e, plate vii. represents an individual that is
ovate, the length being fifteen lines and the breadth twelve lines.
Fragments have been observed which must have belonged to speci-
mens two inches in diameter. The plates are also sometimes
exceedingly convex, the sutures being depressed. In specimens
with smooth surfaces, or with the plates not convex, it is almost
impossible to distinguish the sutures.

Dedicated to Sir Roderick I. Murchison, F R.S., G.S., &e. Ge.
Director-General of the Geological Survey of the United Kingdom
of Great Britain and Ireland; author of “The Silurian System,” ete.

EXPLANATION OF Figures. Plate VII.

Fig. la, Right side of a specimen, shewing the ambulacral orifice and the eight arms.
1b. The left side, shewing the position of the mouth, m. lc. Vertical view
of the ambulacral orifice. 1d, le, Left sides of two other specimens.
if. Apex of le. 1h. Base of 1d, shewing the three basal ae: 1i. Portion
of upper surface of an-arm magnified.

Locality and Formation.— Chazy limestone, Caughnawaga and
Island of Montreal. Fragments are exceedingly abundant; good
specimens rather uncommon.

Collector.—E. Billings.

XV. Matocysrires Barranpt, Billings.
Plate VII. Figs. 2a—2c.

Description.—In this species the body is nearly globular, and the
plates smooth, or very minutely granulated with small tubercles.
The mouth is five-sided, and situated almost exactly in the centre of
the apex or diametrically opposite the point of the attachment of the
column. The arms are two in number, and very short, each being
not more than three or four lines in length. They are so disposed
as to form two half-circles, with the inner curves facing in opposite
directions. They are connected by the usual ambulacral groove, in
the bottom of which is the orifice. There are eight joints in the
arm preserved in the specimen fig. 26, pl. vii. which is the posterior
~ arm, or that most distant from the mouth. The specimen repre-
sented by fig. 2c has the anterior arm preserved, and it shews only
four joints.

68 CANADIAN FOSSILS.

If a section be made passing through the ambulacral orifice, the
mouth and base of a specimen of this species, it will exhibit the
following arrangement of the orifices :—

Fig. 1. Fig. 2.

In the above fig. 1, m is the place of the mouth, aa the anterior
arm, o the ambulacral orifice, pa the posterior arm, c the column,
as the anterior, and ps the posterior side. Fig. 2 is a diagram of a
specimen seen in the direction of the line ob of figure 1, shewing
the arrangement of the arms in two half-circles, one of which is
between the mouth and the ambulaeral orifice, the other being on the
opposite side.

The mouth of this species being five-sided, was probably provided
with valves. It is one line in diameter, and is therefore more than
four times the area of the ambulacral orifice, which has a length
of less than half a line.

Some small specimens in the collection shew that when young this
species was of an oval or pyriform shape.

Dedicated to M. J. Barrande of Prague, Bohemia, author of
‘Systéme Silurien du centre de la Bohéme,” &ec. &e.

EXPLANATION OF Figures. Plate VII.

Fig. 2a. View of the left side ofa specimen ; a, the arm. 2b, Posterior view of the same.
2c. Anterior view of another specimen. 2d. The arm of 2a magnified,
shewing the short branches of the ambulacral furrow to the bases of the
pinnule.

Locality and Formation. — Chazy limestone, near the city of
Montreal.
Collectors. —E. Billings and J. McMullen.

Genus PaLzocystitTes, Billings.

Generic Characters.—The body is oval or pyriform, composed of
numerous plates, which are poriferous; the pores penetrate the

CANADIAN FOSSILS. 69

margins of the plates and extend towards the centre, but do not
open out on the exterior surface. On the interior surface they open
between the edges of the plates. Column, arms and pues unknown.
Generic name from palaios, ancient.

The most abundant species of this genus appears to be identical
with that fossil of the Chazy limestone to which Professor Hall has
given the name of Actinocrinus tenwiradiatus. (See Paleeontology of
New York, vol. i. p. 18, plate iv. figs. 8 and 9.) I have ascertained
however that it is a Cystidean. No perfect specimens have been
found, but several fragments, which I have collected, consisting each
of about one-third of the body, shew that it is a genus allied to
Comarocystites, Spheronites and others of the many-plated group.

This genus appears to be closely related to Amygdalocystites.

XVI. PALMOCYSTITES TENUIRADIATUS, Hall sp.

(Actinocrinus tenuiradiatus, Hall. Pal. N.Y., vol. 1, p. 18, pl. iv, figs. 8 and 9.)

WIZ,
“Zi

Fig. 1. View of exterior of several plates of P. tenuiradiatus.

Fig. 2. Edge of a plate, shewing the entrances of the pores.

Fig. 3. Inside of several plates, shewing the opening of the
pores in the suture.

=.
Wt

y
IX

(Z

SS

(J
MU

Description. —Large specimens are two inches or more in length
and pyriform in shape, the upper part of the body being the largest.
The plates are depressed conical, and when a little worn are all
covered with deep fissure-like striz, which are at right angles to
the edges. These striz cross from one plate to the next contiguous,
so that one half is upon one plate and the other half upon another.
At the suture in the bottom of each of those fissures is a small
aperture that penetrates through, being partly excavated in the
margins of each of the plates respectively. The effect of this mode
of striation is to cover the whole surface of the fossil with small
rhomboidal areas, each of which occupies portions of two plates.
There are as many half-areas on each plate as the plate has sides.
When the surface has not been worn the interesting fact may be clearly

70 CANADIAN FOSSILS.

seen, that all the striz are covered by a thin external layer, which
closed them completely over, so that there were no pore-mouths on
the exterior. It therefore follows, that what appears to be ordinary
strize are in fact the channels of a peculiar set of pores which run
beneath the surfaces of the plate, and communicate with the interior
through orifices in the suture. Hence in a perfect plate, the margin
on the inside is deeply notched, each notch being one-half of a pore-
mouth. On the outside it is not notched. ‘The pores do not open
any where upon the surface of the plate, neither do they communicate
with each other. When the plates are perfect, the surface is still
striated; but the striae correspond to, and are situated over, the
partitions between the channels of the pores which constitute the
striz of the worn plates. ‘The number of pores in the sutures depends »
upon the size of the plates. In a plate, with sides two lines in
length, there are nine pores.

Geological Position and Locality.—Detached plates, common in the
Chazy limestone at Caughnawaga and on the Island of Montreal.
They also occur in the same formation near Hawkesbury, and at
Chazy, in the State of New York.

Collectors —Sir W. E. Logan, J. Richardson, E. Billings, R. Bell,
and J. McMullen.

XVII. Panmocystires Dawson, Billings.

Description —Of this species I have collected several fragments of
the body, two of which are especially interesting, as they exhibit
the exterior of some of the plates, and thus afford the means of
shewing that they are generically related to the last species. The
body is elongated pyriform, or rather fusiform, the lower part being
the smaller extremity. The apex appears to be rounded. The
plates are ornamented with strongly elevated rounded ridges, the
number of which corresponds to the number of the sides ; those with
five sides having five ridges, and those with six or seven sides, six or
seven ridges. Each ridge is continued from the centre of one plate
straight across the suture to the centre of the next. There are no
pore-mouths on the outside ; but on the inside there is one for each
ridge, situated on the suture, exactly as in the last species. The
pores in this species do not penetrate so far towards the centre as in
the last.

The largest specimen collected, is a fragment of the lower half,
and indicates that the length of the body was about one inch, its

CANADIAN FOSSILS. 71

greatest diameter being half-an-inch. Another specimen, nearly
perfect, was about half-an-inch in length, and one-fourth in breadth ;
it was unfortunately destroyed in getting it out of the rock. A
fragment of the top however was preserved, and although half im-
bedded in the matrix, shews clearly enough that it has a rounded
summit. .

Dedicated to Dr. J. W. Dawson, LL.D., author of ‘“ Acadian
Geology,” &c. &c. Principal of the University of McGill College,
Montreal.

Geological Position and Locality.—Chazy limestone, near the first
mile-post, St. Lawrence Street, Montreal.

Collector.—E. Billings.

XVIII. Patawocystires CHAapMaAnt, Billings.

Description —The few plates of this species that have been collected
exhibit the peculiar character of the genus in a most interesting
and satisfactory manner. Without being acquainted with the
structure of the plates, the observer would almost unhesitatingly
refer them to two very distinct species, so great is the change in
their appearance produced by the wearing away of the external
surface. The perfect plates resemble those of P. Dawsoni, inasmuch
as the number of radiating ridges is the same as the number of sides.
The ridges are however of a different form. In P. Dawsoni they
are narrow at the base, and the space between them is flat; but in
P. Chapmani they are broad at the base, or roof-shaped, the base
of each spreading out to a breadth equal to the length of that side
of the plate to which it extends. A perfect plate of this species,
for instance one of six sides, may therefore be described as presenting
six furrows radiating from the centre to the six angles, these
furrows gradually increasing in depth and width as they recede from
the centre of the plate. Or it may be characterised as exhibiting
six roof-shaped ridges radiating from the centre to the sides, and
increasing in height and width at the base as they approach the side.

When however the external surface is worn away, the plates
assume a very different appearance. They then become covered
with deep fissure-like strie, like those of P. tenuiradiatus, to which
they bear so close a resemblance, that to the unpractised eye, they
appear to be the same. They can always however be distinguished
by this character. The ridges or partitions between the fissures,
which terminate at the centres of the sides of the plates, are the

72 a CANADIAN FOSSILS.

highest, those at the angles being the lowest ; but in P. tenwiradiatus
it is the very reverse: the angles of the plate are more elevated than
the centres of the sides.

I dedicate this species to EK. C. Chapman, Esq., Professor of
geology and mineralogy, in University College, Toronto.

Locality and Formation.—Lot 26, Front Concession of Clarence,
Chizy.

Collector.—J. Richardson.

XIX. ArELEocystTirEs Huxteyi, Billings.

Description. —The extraordinary little fossil, for which the above
name is proposed, is no doubt a Cystidean ; but of a group somewhat
widely separated from the ordinary types. There are several speci-
mens in the collection, but they all are half imbedded in stone, and
with one exception exhibit only the dorsal side. The form is sub-
quadrate, rounded at the apex and nearly straight at the base. The
dorsal side appears to have been quite flat when perfect, as the plates
which constitute the edges are bent forward towards the ventral
aspect at more than a right angle, so that the sides instead of being
rounded presented a rather sharp edge. The ventral side was pro-
bably convex.

The plates of the dorsal side are arranged in four series. The
basal series consists of four oblong plates, each of which is about
twice as high as wide. These four constitute rather less than the
lower half of the body.

In the second series there are three plates, the central one being
broader than either of the other two ; it rests upon the upper edges
of the two plates which form the central pair of the basal series, and
is about equal to them in width. The right side of this plate is
longer than the left, owing to the truncation of the upper left hand
angle. These three sides occupy a little more than one-fourth of the
length of the dorsal side.

The third series consists of an irregular row of four or five small
plates. There are two at the sides, and apparently three others
resting on the large central plate of the second series. Of these
however only two are distinctly visible, one in the centre and the
other on the left sloping upper side of the plate below.

The fourth series is composed ofa row of three or four small plates,
forming the margin of the cup on the dorsal side. Above these and
imbedded in the matrix are several small points which are suggestive
of the marginal ambulacral ossicula of the ordinary Cystidee.

CANADIAN FOSSILS. 13

One specimen shews a portion of the ventral side, consisting of
numerous small plates, thus resembling the genus Pleuwrocystates.

The two large side-plates at the base are obscurely striated trans-
versely. The body is one-third longer than wide. The plates are thin.
The length of the largest specimen a little more than half-an-inch ;
width about four lines. All the characters that can be collected from
the specimens are comprised in the above description. They are
sufficient to shew that this is a distinct genus, and I propose for it the
name of Ateleocystites from the Greek ateles, “ defective or incomplete.”

Professor Hall has kindly furnished me with some of the printed
sheets of his forthcoming Vol. 3 of the Paleontology of New York,
in which he has described a new genus Anomalocystites, from the
Lower Helderberg series. The materials in my possession are not
sufficient to enable me to refer the above to the New York genus.

The genera of Cystidez have not usually so great a vertical range
as that between the base of the Trenton and the top of the Upper
Silurian. Should it be ascertained hereafter that the two genera are
identical, this species must be referred to Anomalocystites, which has
the precedence.

Another form belonging to this group has been discovered in the
Upper Silurian in England.

Fig. 4.

The above wood-cut, fig. 4, represents the structure of the dorsal
side as nearly as can be made out from the specimens in the collec-
tion.

The species is dedicated to T. A. Huxley, Esq., F.R.S., of the
Geological Survey of the United Kingdom.

Locality and Formation.—Trenton limestone, farm of Mrs. Brigham,
Township of Hull, near Ottawa.

Collector —K. Billings.

In addition to the nineteen species of Cystideans described in the
foregoing pages, there are fragments of two others, which are too
imperfect to indicate the genus; but still sufficiently well preserved

74 CANADIAN FOSSILS.

to shew that they do not belong to any known species. One of
them appears to be a Glyptocystites, and the other will I think yet
turn out to be a small Cystidean of a new genus, with a nearly
globular body, and three or four pectinated rhombs. I have seen
them only in the Trenton limestone at Ottawa.

On the ASTERIADA of the Lower Silurian Rocks of Canada. By E.
Binuines, Esq., F. G. 8S.

The following species of Star-fishes were described in the Report
of the Geological Survey published in 1857, page 290 e¢ seg., with
the following introduction :—

‘‘ The species of Star-fishes in the collection appear to be referrable to the genera pro-
posed by Mr. Salter at the meeting of the British Association, in August last. I have
seen no other description of these genera than that given in Silliman’s Journal of
November, 1856, which is as follows:

“ PaL#ASTER.—Without disc, avenues deep.
‘¢ Pal MASTERINA.—Pentagonal, disc moderate.
‘¢ Panmocoma.—No disc, avenues very shallow.

“Tt is probable that our species, when opportunity can be had for a direct compa-

rison with British specimens, wili be found congeneric.”

‘Since then Mr. Salter has published full details of the above and
some other genera,* and I have also examined some of the species
described by him and Prof. Forbes.

* On some New Paleozoic Star-fishes. By J. W. Salter, Esq., F.G.S. Annals and
Magazine of Natural History, November, 1857.

The above diagram is given to explain the sense in which the following terms are

used in this memoir :

a, Ambulacral ossicles,—the small plates in the bottom of the ambulacral furrows,
between which the pores for the passage of the suctorial feet pass.

b. Adambulacral plates,—the rows of plates which border the ambulacral grooves.

m. Marginal plates,—the row of plates round the margin of some of the species.

0. Oral plates,—situated at the angle of the mouth. In many species these consist of
the ten terminal adambulacral plates.

Disc-plates,—I propose to call all the plates of the body which cannot be comprised in
any of the above four classes, disc-plates.

&
76 : CANADIAN FOSSILS.

After much consideration, I have resolved to adopt the following
arrangement for the Canadian species.

Genus PALASTERINA, McCoy.*
(As defined by Mr. Salter, 1857.)

Generic Characters.— Pentagonal, depressed; the arms a little
produced, with three or five principal rows of tubercles above, com-
bined with a plated disk which fills up the angles; ambulacra rather
shallow, of sub-quadrate or slightly transverse ossicles, bordered by
a single row of squarish large plates, the lowest of which (ad-oral
adambulacral plates, Huxleyt) are large and triangular, leaving
combs of spines.”

The following species having been already placed in the above
genus, I am unwilling to create a new one for them until more is
known as to what constitutes a generic character among the Star-
fishes. Our specimens do not shew any spines, but perhaps they
have not been preserved; and even could it be shown that P. stellata
was without these appendages, it would still remain to be settled
whether this difference is or is not of generic importance.

I. PALASTERINA STELLATA, Billings.

Plate IX. Fig. 1a, 15.
(P. stellata, Geological Survey of Canada, Report, 1856, p. 290.)

Description.—Pentagonal ; disc about one half of the whole diame-
ter; ambulacral grooves narrow and deep, bordered on each side by
arow of small nearly square adambulacral plates; a second row con-
sisting of disc plates extends nearly to the end of each ray, the
remainder of the disc covered with smaller plates. All of these plates
are solid and closely fitted together; the disc-plates in the angles in
contact with the oral plates are much larger than any of the others.

In the only specimen in the collection the length of the rays mea-
sured along the ambulacral grooves is three lines ; number of adam-
bulacral plates on each side of the grooves sixteen; the rays diminish
somewhat rapidly in size, and terminate in a rounded point; dia-
meter of the disc four lines. The plates are all a little worn, so that
the character of their surfaces cannot be observed ; they were pro-
bably nearly smooth.

* Suggested by Prof. McCoy, who did not however define the genus. British Palxo-
zoic Fossils, p. 59, 1851.
t Angle-ossicula (Forbes), oral plates of this memoir.

CANADIAN FOSSILS. 17

EXPLANATION OF FIGURES.

Fig. la. The specimen natural size.
1b. The same enlarged.

Locality and Formation.—City of Ottawa. Trenton limestone.
Collector.—E. Billings.

IJ. PaLAsTerrInA RuUGOSA, Billings.

Plate IX. Fig. 2a, 2b, 2c.
(Geological Survey of Canada, Report, 1856, p. 291.)

Description—Two inches in diameter; rays five, acute at their
apices and rapidly enlarging to a breadth of four lines at the disc,
which is eight lines in width. The specimen shews the upper side
of the fossil only ; some of the plates are absent from the centre of
the disc, but those which remain are very prominent in their centres,
and roughly ornamented with four or five deep crenulations or fur-
rows from near the centre to the edges, producing ‘a star-like appear-
ance resembling a half-worn plate of Glyptocrinus decadactylus; their
diameter is from one to two lines.

The rays are composed (at least the backs and sides of them,) of
four rows of plates, which are so very prominent that they appear to
be almost globular, and even pointed in their centres; the central
rows are the smallest; the first four plates of the outer row occupy
three lines in length, and of the inner rows nearly as many. To-
wards the point of the arm all diminish rapidly in size.

Beneath the outer rows two others can be seen, which are pro-
bably the outer marginal plates of the under side, corresponding to
those of P. rigidus.

EXPLANATION oF Figures. Plate IX.

Fig. 2a. Dorsal view of a specimen. 26. Fragment of another individual. 2c. One of
the plates of 2a enlarged.

Locality and Formation.—Charleton Point, Anticosti. Hudson
River Group.
Collector —J. Richardson.

Genus STENASTER, Billings.

Generic Characters.—No disc; rays linear, lanceolate or petaloid ;
grooves bordered by solid oblong or square adambulacral plates ;
oral plates triangular and ten in number; two rows of ambulacral

78 CANADIAN FOSSILS.

pores. Dorsal side of disc and rays covered with small plates, which
appear to be tubercular and not closely fitted together. The generic
name is from the Greek stenos, narrow, in allusion to the contracted
body.

As it has been suggested that the two species hereinafter described
should be referred to Palgaster, I give the following figure of that
genus in order to show the difference.

Fig. 1, Paleaster Niagarensis, Hall.

Upon examining the above figure, it will be seen that there is a
great difference between Stenaster and Paleaster, for the following
reasons :

1. If the large plates which border the groves in Paleaster be
adambulacral, then there are only five oral plates, whereas in Sten-
aster there are ten.

2. But if they be not adambulacral but marginal plates, then
Paleaster must have both marginal and adambulacral, while Stenaster
has only the latter.

III. Srenaster Sauter, Billings.
Plate X. Fig. 1a, 10.

Description.—This species has rather short broad rays, which are
narrower where they are attached to the very contracted body than
they are at about the centre of their length. In consequence of this
form, the sides of the rays are not parallel, but a little curved out-
wards. As however only two specimens have been collected, and —
both appear to be a little flattened by vertical pressure, it may be that
this leaf-like shape of the rays is accidental, and that in perfect spe-
cimens they taper uniformly from the body outwards. The adambu-
lacral plates are oblong, and the sutures between them are nearly at
right angles to the ambulacral grooves; those next the body are a

CANADIAN FOSSILS, 79

little sloping outwards. Their length is about twice their breadth,
and they are so disposed that the greater dimension is transverse or at
right angles to the groove; the extremities which lie next to the
grooves are angular, and some of them appear to have the contiguous
pores partly excavated in them. The oral plates are acutely trian-
gular, the sharpest angle being towards the mouth. The plates are
smooth. The ambulacral pores are very large, and the ossicles are
much contracted in the middle and greatly expanded along the
median line of the bottom of the groove.

The most perfect specimen is one inch in diameter measured
between the tips of the rays; diameter of disc three lines; width of
ray at mid-length two lines and a half.

Dedicated to J. W. Salter, Esq., Palzontologist of the Geological
Survey of the United Kingdom.

EXPLANATION OF Figures. Plate X.
Figure la.—Ventral view of a specimen collected at Belleville.

1b.—The same enlarged.

Locality and Formation.—Belleville, Canada West. Trenton lime-
stone.

Collector. —K. Billings.

IV. STENASTER PULCHELLUS, Billings.

Plate X. Fig. 2.
(Paleaster pulchella, Geological Survey of Canada, 1856, p. 292.)

Description.—Rays long, slender and sub-cylindrical ; adambula-
cral plates transversely oblong; grooves narrow; dorsal plates small
and tubular. Diameter of the only specimen in the collection two
inches and one-fourth measured between the tips of the rays; rays
one inch in length, and two lines and a-half in width at the base;
disc three lines and a-half in diameter.

EXPLANATION OF Figure. Plate X.

Fgure 2.—Ventral view of the only specimen collected.

Locality and Formation.—Ottawa. Trenton limestone.
Collector.—K. Billings.

Genus PETRASTER, Billings.

Generic Characters—This genus has both marginal and adambula-
cral plates, with a few disc-plates on the ventral side. The general

80 CANADIAN FOSSILS.

form is deeply stellate, and the rays long and uniformly tapering.
A single specimen has been collected, and as it shews the under side
only, the characters of the dorsal surface cannot be given. The
structure of the mouth is also unknown. Generic name from petra,
a stone.

It differs from Palasterina by the presence of large marginal plates
outside of the disc-plates, and still more from Stenaster, which has
neither disc nor marginal plates. It is allied to Astropecten.

V. PETRASTER RIGIDUS, Billings.

Plate X. Fig. 3.
(Palasterina rigidus, Geological Survey of Canada, Report, 1856, page 291.)

Description—This species has much the aspect of an Astropecten;
the disc is one-fourth the whole diameter, the rays rather slender and
uniformly tapering; the angles between the bases of the rays round-
ed. The plates, which appear to be adambulacral, are quadrate and
a little convex; the marginal plates oblong, and also convex; the
disc-plates consist of three at each angle, and a single row on each
side of the ray, but extending only one-third or one-half of the length
of the ray; they all lie between the marginal and adambulacral
plates.

The specimen figured was about two inches in diameter when per-
fect; width of disc half-an-inch, and of rays at the base about three
lines.

EXPLANATION OF Figure. Plate IX.

Fig. 3a.—Ventral view of an imperfect specimen.
Fig. 3a appears to be the dorsal side of an individual of this species with the plates
along the centre of the rays removed.

Locality and Formation.—Trenton limestone, Ottawa.
Collector.—J. Richardson.

Genus THNIASTER, Billings.

Generic Characters—Body deeply stellate; no disc or marginal
plates; rays long, slender, flexible, and covered with small spines ;
two rows of large ambulacral pores; adambulacral plates elongated
and sloping outwards so that they partly overlap each other ;
adambulacral ossicles contracted in the middle, dilated at each end.
Generic name from tainia, a riband.

a

CANADIAN FOSSILS. 81

This genus differs from Protaster as described by Mr. Salter in the
Annals and Magazine of Natural History, November 1857, in the
following particulars :—

1. Protaster has a well-developed disc.

2. It has also the pores outside of the ambulacral ossicles. See
Mr. Salter’s fig. 4c, in the article above cited.

3. The same figure shows that the oral plates of P. Miltoni are
formed of two of the ambulacral ossicles, instead of two of the
adambulacral plates.

These differences are too great to admit of our species being at all.
unless very remotely, allied to Protaster.

VI. TaNIASTER sprnosus, Billings.

Plate X. Fig. 3a, 36, 3c, 3d.
(Paleocoma spinosa, Geological Survey of Canada, Report, 1856, page 292.)

Description.—The specimens collected are about seven lines in
diameter; the rays linear-lanceolate, one line in width at the base,
and covered at the sides with numerous small spines.

In the view of the enlarged specimen (pl. x. 3b), the ambulacral
ossicles appear in some places to alternate with each other, but this
is owing to a distortion. Those on one side of the furrow are opposite
those upon the other. The adambulacral plates are elongated, and
so placed that the outer extremity of the one lies upon the inner
extremity to the next. The rays are flexible.

EXPLANATION oF Figures. Plate X.
Figure 3a.—Ventral view of a small specimen.
3b.—The same enlarged.
3c.—Another specimen, with the rays bent upwards.
3d,—The same enlarged.
Locality and Formation.—F alls of Montmorency, Trenton limestone.
Collector.—K. Billings.

VII. TNIASTER CyLinDRICUS, Billings.

Plate X. Figs. 4a, 40.
(Paleocoma cylindrica, Geological Survey of Canada, Report, 1856, page 292.)

Description.—About an inch and a half in diameter or a little more;
rays sub-cylindrical, regularly rounded on the upper side, flattened
on the lower, covered above with spines; about a line in width at.
the base, and tapering to an acute point. .

E

82 CANADIAN FOSSILS.

This species is larger and more robust than the former. Both
appear to be somewhat common, and the specimens are often found
with their rays variously curved, showing that they were extremely
flexible.

EXPLANATION OF Figures. Plate X.

Figure 4a.—Dorsal view of a specimen.
4b.—Ventral view of a different specimen.

Locality and Formation.—City of Ottawa. Trenton limestone.
Jollector.—K. Billings.

Genus EprioasTER, Billings.
(Genus Cyclaster, Geological Survey of Canada, Report, 1856, page 292.)

Generic Characters.—Body sessile, circular, discoid, covered with
numerous irregularly polygonal plates; mouth large, sub-pentago-
nal; five ambulacral grooves, each composed of two series of oblong
ossicles; four rows of ambulacral pores to each groove. The mouth
is formed of five oral and apparently five internal ossicles. The
sutures between the ambulacral ossicles, in certain conditions of pre-
servation, are enlarged so that the pores on each side are connected,
and thus there appear to be two instead of four. Hence in the first
description I gave of this species it was described as having two
rows. Since then more perfect specimens have been procured, and
IT am enabled to correct this misconception. Generic name from
edriao, to seat, in allusion to the sessile condition of the species.

In my report for 1856 this genus is called Cyclaster ; but I find
that this name had been a short time previously given to a genus of
sea-urchins by M. Cotteau, and it is therefore necessary now to pro-
vide a new one. (See Catalogue des Echinides Fossiles des Pyrénnées.
Par MM. Leymerie et Cotteau. Bulletin de la Société Géologique
de France, 18 Fevrier 4 17 Mars 1856.) This number of the Bulle-
tin was published in March 1857, but my Report was not issued until
the autumn following.

VIII. Eprioasrer Biessyti, Billings.
(Cyclaster Bigsbyi, Geological Survey of Canada, Report, 1856, page 293.)

Description.—The body of this species is circular, about one inch
and a half across, and half an inch in height in the centre. It is
covered with numerous small plates of various sizes, and, except in
the ambulacral areas, disposed without order. The mouth, situated

CANADIAN FOSSILS. 83

in the centre of the upper side, is about two lines in diameter, and
apparently five-sided. The other aperture between the rays consists
of a space covered with plates much smaller than the average size;
these form a small elevation, which is imperfect in all the specimens
I have seen, but enough remains to render it almost certain that
there was an aperture of some kind in this place.

The ambulacral areas are five in number, radiating from the mouth,
precisely like those of a common star-fish, and composed of two
series of oblong plates which alternate with each other in the centre
of the furrow. There are about ten of these plates to five lines in
length, on each side of the ambulacrum. The pores pass between
the plates, two being situated between each two. The ambulacra
are three lines wide at the mouth, and about an inch and a half in
length in full-grown specimens. As they recede from the centre
they curve round towards the right in some specimens, and towards
the left in others.

The mouth appears to be composed of ten plates; five of these are
at the ends of the ambulacra, and the other five placed in the angles
between the ambulacra. In some of the specimens the plates are all
smooth, in others covered with small tubercles.

All the specimens that I have collected were seated upon the rock
with the mouth upwards, and apparently somewhat flattened by
pressure. It is probable that when perfect they were more globular
than they are present. One specimen is detached, and shows that
the plates covered the whole of the under surface, except a small
space in the centre which appears to be without plates; perhaps
this was the point of attachment; I see no evidence of a column.

Dedicated to Dr. Bigsby, one of the most able of the first explorers
of the geology of this country.

I regret, that, in consequence of mistaking the meaning of Prof.
E. Forbes’ remarks on the genus Agelacrinites in his memoir on the
British Cystideze, I supposed this to be the specimen discovered by
Dr. Bigsby, and accordingly gave it his name. Since then I have
seen Dr. Bigsby’s specimen, and find it to be A. Dicksoni. It is too
late now to change the names.

EXPLANATION oF Figures. Plate VIII.

Figure 1.—Upper side of a specimen partly embedded in stone.
la.—A polished section through the mouth and two of the grooves, showing
that the pores penetrate through.
2.—Fragment of a crushed specimen, showing two of the rays.
2a.—A portion of fig. 2 enlarged to show the pores.

Locality and Formation.—City of Ottawa. Trenton limestone.
Collector.—E. Billings.

84 CANADIAN FOSSILS.

AGELACRINITES Dicxsont, Billings.

Plate VIII. Figs. 3, 3a, 4, 4a.
(A. Dicksoni, Geological Survey of Canada, Report, 1856, page 294.)

escription.—The diameter of this species is from three quarters of
an inch to an inch and a half; the rays are five in number, and con-
structed upon a plan somewhat different from that of E. Bigsbyi,
being bounded by two rows of small plates, which rise from the
surface and arch over the grooves. The upper ends of the plates on
one side meet those of the opposite side, in a line along the centre
of the ray, thus forming for each ray a sort of covered way. The

spaces between the rays are paved with numerous flat sub-imbrica-.

ting plates. The specimens do not show the central aperture dis-
tinetly, but between two of the rays there is an orifice which appears
to have been surrounded by small plates. The width of the rays at
their bases is from one to two lines, according to the size of the
individual, and they taper uniformly to their extremities. In all the
specimens J have seen, the rays curve round to the right hand, if we
suppose that the side with the aperture is posterior. The marginal
plates of the rays do not appear to alternate regularly, as in some of
the figured species of this genus.

There are two rows of small circular indentations on each side of
the rays, corresponding in their position to the ambulacral pores of
E. Bigsbyi, only that in the latter they are in the bottom of the
grooves. It cannot be ascertained whether they penetrate through
between the marginal plates or not.

I have dedicated this species to Andrew Dickson, Esquire, of
Kingston, C. W., one of the best workers in the field of Canadian

geology.

The first specimen was discovered by Dr. Bigsby at the Chau-.

diére Falls, at Ottawa, in 1822.

EXPLANATION oF Figures. Plate VIII.

Figure 4.—The original specimen discovered by Dr. Bigsby, and now in the
Museum of Practical Geology, Jermyn Street, London.
4a.—The same enlarged.
3.—View of a different specimen, in the collection of the Geological
Survey of Canada.
3a.—The same enlarged.

Locality and Formation.—City of Ottawa. Trenton limestone.
Collectors ——Dr. Bigsby, E. Billings.

CANADIAN FOSSILS. 85

I have placed E. Bigsby: in the order Asteriade, because its
structure appears to me to be more like that of the Star-fishes than
that of the Cystideee. None of the Cystidee have ambulacra whose
pores penetrate through the covering of the body, and therefore all
such genera as Edrioaster, Agelacrinites and Hemicystites, belong to a
very different division of the Echinodermata. When we know more
of their structure it is probable that they will be arranged as a
sub-order, for which the name Edrioasteride would be appropriate,
as it would suggest their sessile condition on the one hand, and on
the other their affinity to the Asteriade.

On CYCLOCYSTOIDES, a new genus of Echinodermata from the Lower and
Middle Silurian Rocks. By J. W. Saurer, Esq., of the Geolo-
gical Survey of Great Britain; and E. Bruuines, Esq., of the
Canadian Geological Survey.

Under this name we wish to describe a form which has come
under the notice of each of us—in the one case in a series of
instructive specimens shewing the structure of the different parts
from the Trenton limestone rocks of Canada; and in the other, a
specimen shewing the entire form and general surface, which has
been long known in the Llandovery Rocks or May-Hill Sandstone
of England.

The affinities of the fossil may perhaps be better discussed when
the structure of the two species with which we are acquainted has
been described.

Genus CYCLOCYSTOIDES, Billings and Salter. LATER?

Generic Characters—Discoid, surfaces formed of an integument
composed of numerous small granular plates, which appear to be
radiately arranged; margin entirely surrounded by thick subquadrate
plates, each of which presents upon its outer half two deep obtusely
oval excavations. These, in perfect specimens, are covered over by
minute polygonal plates, thus forming a tubular channel around the
whole animal. This channel appears to have been connected with
the interior by small pores penetrating through the marginal plates,
there being one pore leading from each of the excavations. The
margin or (perhaps) dise was also connected with a long tube, like
the proboscis of some of the Crinoids, formed of many small polygo-
nal plates.

I. CycLtocystroiwes Haut, Billings.

Description.—F lat, circular, from one to two inches in diameter ;
about thirty-six marginal plates, the unexcavated inner portions of
which are subquadrate, convex, and slightly granular upon their

CANADIAN FOSSILS. 87

surfaces. The two marginal excavations of each plate are separated
by a thin wall-like partition, and bordered at the sides and outer edge
of the plate by a sharp rim. It thus follows that the channel around
the margin of the animal was divided into twice as many compart-
ments as there are marginal plates. The integument of the upper
side, supposed to be the side on which the marginal plates are
excavated, is connected to the inner edge of those plates, and does
not extend over them; its surface is roughened by small tubercles.
The integuments of the under side appears to extend under the
marginal plates, and connect with the small plates which cover the
excavations above.

Fig. 6 represents the remains of a specimen which was perfect, but
imbedded in the rock to such an extent that only eight or nine of the
marginal plates and a small portion of the integument of the upper
side were visible. It was silicified, but not to such an extent as to
resist completely the action of hydrochloric acid. It shewed clearly
that the integument was attached to the inner edges of the marginal
plates.

The following description of the figures contains all that can be
be said further about these specimens :—

The specimens, four in number, collected by Sir William E. Logan,
shew :—

1. In fig. 1, an impression of a nearly complete disk, more than an
inch broad, with all the marginal ossicles complete. They form very
nearly a circle, deficient only at one point, a, which may be only
accident, or possibly as both the outer rim and inner series of ossicles
are deficient at this point, it may indicate the position of a stem or
attachment. At one other point, 6, the margin is broken, but the
inner row of ossicles appears to be continuous, so that if there be
not an attachment at a—and no trace of any appendage exists—the
animal was most probably free.

2. Fig. 2 shews the marginal plates, and in a good state of preser-
vation, of more than three-fourths of the ring. There are twenty-six
of these, and their form is rudely sub-quadrate, rounded on the inner
margin, truncate and bilobed on the outer; each is divided into two
conspicuous halves, of which the inner is convex, granuloso-tuber-
culate, and with close, parallel, vertical striz on their sides (fig. 30) ;
the outer half, on the contrary, is deeply excavate, smooth, divided
by a radiating ridge into two shovel-shaped portions, which at their
inner base are each deepened into a circular pit, with a tubercle
in it (as seen more plainly in the cast, fig. 6 anda). The outer free

88 CANADIAN FOSSILS.

~

edge, 3d, is furnished with one, two, or more transverse plates, which
also appear granular, supporting other smaller ones which appear
to fill up all the space over the excavations, and to form a sort of
polygonally plated tube. This tube is nearly complete at a, fig. 1,
and from near this point a similar but truly cylindrical tube extends
out beyond the ring of ossicles, and is seen at 6 complete, and at ¢
with its upper surface broken away, forming a continuous tube fully
three-quarters of an inch beyond the disk, and apparently not termi-
nated even then; 2d* shews it magnified.t

3. Fig. 5 shews a still more complete development of this mar-
ginal plating, and the difference in size of the basal plates (see fig. 5*
and the marginal ones, 4) is such as to suggest the idea of a distinet
species. It is perhaps only a younger specimen, considerably abra-
ded, hut may however receive provisionally the name of C. depressus.
The specimen 5 shews a considerable portion of the loosely-
arranged and flattened ossicles of the disk, which are not closely
plated, but leave large interstices between them. This structure is
better seen in the small fragment of the central disk of figure 2
(magnified in figure 4), in which the granular surface of the plates,
and their irregular arrangement with interstices, is very distinct.

Figs. 8 and 9 shew still more clearly the radiated structure of
the upper surface in another species.

Fig. 6 is the opposite or under-side (at least the flatter and less
ornamented side), and may be presumed to be C. Halli. The great
ossicles here are marginal, and have no plated integument stretching
out beyond them, the outer edge, 64, corresponding to the edge, 3d,
on the opposite face.

The silicified specimen, 6, has been macerated in muriatic acid to
expose it, and has suffered abrasion—neither the marginal ossicles,
b, nor the reticular surface, a, shewing so clearly as they should do
the rea] structure of the surface. Ataa portion of the upper-side
is seen, viz., impressions of three of the large granular ossicles,
with their external deep pits (represeuted in the cast as circular
elevations, with a minute central pit in each).

It is this specimen which so satisfactorily explains the meaning of
the cast next to be described, and which, though differing specifically
and from another formation, also helps materially to elucidate the
specimens already described.

} Upon a re-examination of this specimen I can detect no connection between the
fragment of the tube and the disc, although it may have been connected.—H. B.

CANADIAN FOSSILS. 89

We dedicate this species to Professor J. Hall, the distinguished
paleontologist of the New York survey.*

Locality and Formation —Trenton limestone, City of Ottawa, and
Lake St. John.
_ Collectors—Sir W. E. Logan, E. Billings, J. Richardson.

IJ. CycLtocystoipes Davisi, Salter.

OC. ovalis ? uncialis et ultra, ossiculis marginalibus 48-49, convexis, levigatis,
exius profunde excavates, simplicibus nec radiatim bilobis, margint recurvo»
superficie obscure 8, radiato.

This species certainly differs from the American one in that the
number of marginal ossicles is much greater (forty-eight or forty-nine),
while the ossicles themselves, instead of being granular, are smooth,
and have the outer division much deeper, the margin being produced
upwards as a distinct rim. Neither the division of the ossicles in
this outer portion into two lobes, nor the separation of one ossicle
from its neighbour, is at all distinctly marked; but just at the base
of the deep excavation short-raised ridges indicate faintly these
divisions, while the annular pits at the bottom are still deeper and
more distinct than in the C. Halli.

This species shews the complete surface, on which about as many

* Professor Hall in 1851 described a species of this genus in the paleontological part
of Foster and Whitney’s Report on the Geology of Lake Superior, page 209. Each of
the specimens which he figures (see plate xxv. fig. 4, a, b,c, of the work cited) exhibits
twenty-nine marginal plates. The smallest of ours (plate x. figure 5 of this decade)
although exactly the size of the largest figured by Prof. Hall, has thirty-six, and so have
our two largest. The Escanaba specimens are therefore most probably of a different
species, which has not yet been named. The following is Prof. Hall’s description :-—

‘“This body consists of a ring, or a sac, the upper edge of which only appears,
composed of numerous plates joining by their broader edges. The upper or exposed
surface of the plates is sculptured or granulated, convex, and not closely joined together
at the upper angles, presenting the appearance of somewhat quadrangular tubercles ;
exterior margin of each plate furnished with a thin wing-like expansion, marked by two
diverging ridges. ;

“This curious body is evidently Crinoidean, from the character and structure of the
plates. The ring presents an appearance very similar to the row of plates surrounding
the valves which close the ovarian aperture in some Cystideans, but the number is far
too great, being in one specimen twenty-nine, and apparently not less in the other.
The inner faces of the plates moreover do not present any appearance, as if for the
attachment of other plates or valves. It is possihle that it may be the elevated
marginal ring of some one of the sessile Crinoids, though the arrangement of the plates
is more regular than in any species known to me.

“ Locality.—Banks of the Escanaba river, two miles below the mouth of Indian
creek, in the Trenton limestone.”

90 CANADIAN FOSSILS.

radiations mark the margin as there are ossicles, and the centre of
the flat disk is occupied by a star of about eight narrow rays, witha -
central depression. All of these markings are obscure, but were still
capable of demonstration in the specimen (unfortunately since lost,
after an accurate drawing had been taken).

The margin is peculiarly deep and raised like a rim all round; the
outer half of the ossicles, being deprived of radiating ridges, combine
to form a smooth channel. The deep-set annular pits shew on the
cast as projecting rings with a central depression.

Locality.— May-Hill Sandstone of Prof. Sedgwick (Upper Llando-
very Rock, Murchison), Presteign, Radnorshire, South Wales.
Found by J. E. Davies, Esq., F.G.S.

Regarding the affinities of the fossils, the choice seems to be
between Star-fishes and Cystidez.

At first sight of the more perfect evidence thus brought together—
for neither the Canadian or British specimens are complete without
the other—the impression certainly was, that we had here a truly
circular Star-fish, an extreme form of what is so often approached
by some of the Gonialites of the chalk formation. We have figured
one (figure 10) to illustrate this comparison, where the marginal
ossicles of the disk and of the rays are so much alike, and the latter
much shortened as to present nearly a circular outline.

In the loosely reticular skeleton of the disk there is an addi-
tional character, very common in Star-fish, but rare in Crinoids or
Cystideee. Against this supposition there is the peculiar excavation
of the marginal ossicles, not for the attachment of large marginal
spines, such as Goniaster and other star-fishes often exhibit on a small
scale, but forming a hollow space, covered over with closely plated
ossicles.

The discovery of the long tube, fig. 2, 6, c, made (during the etch-
ing of the specimens) by our valued friend, Mr. Sowerby, threw still
further doubt on this explanation. It appears as if continuous (though
the connection cannot quite be traced,) with the marginal tesselated
portions (a, a), and if this were the case there would be a channel
running along the outer margin of the disk, and thence out freely at
one end, a structure incompatible with that of any known Star-fish,
or indeed any Echinoderm whatever. If on the other hand compa-
rison be made with certain known forms of Cystidez, although the
reticular structure of the disk is abnormal, yet in the arrangement of
the marginal ossicles there is a not indistinct resemblance to such
forms of Cystidez as Pseudocrinites (fig. 12), or perhaps still nearer to
the Canadian form Amygdalocystites, described by one of the authors.

On the Paleozoic Bivalve ENvomMostraca of Canada. By T. R. _
JONES, Esq., F.G.S.

I. Beyricuia LoGant, Jones.

Plate XI. Figs. 1-5.
(Annals of Natural History, 3d series, vol. i. p. 244, plate ix. figs. 6-10.)

Length 7;, breadth 3, inch.

This is a small Beyrichia of the unisulcate group (‘ Simplices,”
Annals Nat. Hist., 2 ser. vol. xvi. p. 85); variable in shape, from
reniform to oblong; dorsal edge straight, extremities rounded and
almost equal; ventral edge varying in its convexity. Surface of the
valves somewhat depressed, most convex a little above the median
line, sloping more gently to the ventral than to the dorsal margin ;
usually punctate, sometimes smooth; always bearing a distinct nar-
row depression on the dorsal region, usually on its anterior third ;
this dorsal notch reaches across a third or even more of the breadth
of each valve. Ventral and terminal margins bordered by a narrow
depressed rim.

I cannot regard the extreme shapes of the gregarious and innume-
rable individuals of this Beyrichia as typical of specific distinction.
The general form, the relative convexity, and the dorsal notch are
the more characteristic features.

a. Var. reniformis. The extreme of the kidney-shaped form is well
shown in fig. 1, a specimen from Hawkesbury, where this shape
occurs, with many of oblong outline, and others of intermediate shapes.
The specimen here figured is strongly punctate: smooth specimens
of this variety occur at Grenville.

b. Var. leperditioides. In fig. 5 we have one of the specimens in
which the antero and postero-dorsal corners of the valves become
modified towards the well-marked oblique dorsal angles of Leperditia.t

Locality and Formation—Grenville and Hawkesbury ; with the
following species in the lower part of the Chazy.

Collector.—Sir W. KE. Logan.

+ See p. 92 for further remarks on B. Logani and its varieties, in relation to L.
Canadensis.

92 CANADIAN FOSSILS.

II. Lererpit1a CAaNADENSIS,* Jones. a. Var. NANA.

Plate XI. Figs. 6, 7, 9, 10.
(Annals of Natural History, 3d series, vol. i. p. 244, plate ix. figs. 11-15.)

Length 1, breadth ,, inch.

Small; somewhat variable in shape, but always retaining the
characteristic Leperditia-outline, with straight back, more or less
obliquely-rounded belly, and sloping dorsal angles. Carapace usually
short (the height or breadth being about two-thirds of the length),
somewhat variable in the amount of convexity (thickness), which is
usually greatest at the antero-ventral third. Surface smooth. EHye-
tubercle generally well marked, and muscle-spot often distinct ; but
occasionally the latter becomes involved in the nuchal depression,
and the former is sometimes obsolete.

This is the smallest form of Leperditia which I have yet met .with.
It occurs in great numbers, together with Beyrichia Logani in equal
abundance, in a dark-grey friable limestone, mainly composed of these
Entomostraca, fragments of trilobites and shells, at Grenville and
near Hamiltonville in Hawkesbury, on the Ottawa. This Leperditia
limestone forms pat of a band of limestone, about two feet thick,
which extends over a wide district?, and is of importance as marking
the position of a continuous band of rock holding nodules of phosphate
of lime which is beneath it; it belongs to the base of the Chazy
limestone.

This variety of L. Canadensis occurs also in a dark-grey, crystalline,
shelly limestone (of the Calciferous Sandrock) on the north side of
Grande Isle, in the St. Lawrence. In two hand specimens of this
limestone a few separate valves and one pair of valves are present.

Beyrichia Logani and Leperditia Canadensis, var. nana, occur toge-
ther in immense numbers, forming indeed a considerable portion of
the limestone rock in which they are chiefly found. I believe
that the former is not the young of the latter (although perhaps
the differences of shape and structure are not greater than such
as we find to occur between the young and adult forms of recent
Entomostraca and other Crustacea), because, where the allied Beyri-

* Referred to in Quart. Journ. Geol. Soc. vol. viii. p. 202 and p. 207.

} ‘This rock, having been quarried for lime-burning in several places, has been
followed from Carillon to Grenville (thirteen miles).” Quart. Journ. Geol. Society,
vol. viii. p. 207; and Logan’s Report Geol. Surv. Canada, 1851-52, p. 18.

t Quart. Journ. Geol. Soc. vol. viii. p; 202 ; and Logan’s Report, 1851-52, p. 15.

CANADIAN FOSSILS. 93

chia, such as B.strangulata,* B.mundula, and B. simplex, occur, even in
as great numbers, in the rocks of other localities, the Leperditie are
not found with them; the latter also occur unaccompanied by these
Beyrichie, L. Canadensis itself being found alone in Grande Isle. The
close resemblance in outline of some specimens of B. Logani (var.
B. leperditioides, fig. 5) to the Leperditia is, I believe, merely a mimetic
resemblance of outline, such as we find taking place among many
groups, both of the lower and the higher animals.

6. Var. LABROSA.

Plate XI. Fig. 8

Length 7, breadth 7; inch.

The extremities of the valves in this specimen from Hawkesbury are
marked by a broad marginal depression, which is continued less
strongly along the ventral border, and the antero-dorsal corner is
more produced than usual.

This may be an individual modified by accidental circumstances of
growth.

c. Var. LOUCKIANA.
Plate XI. Pig. 11.

Specimens of possibly the same species as the foregoing, but of a
considerably larger size (often twice as large), occur in two other
limestones, specimens of which Sir William Logan has confided to
my examination.

Imbedded in bits of black fine-grained limestone from Louck’s Mill,
on the Castor River, in the township of Russell, are three glossy black
Seah in good preservation, and of different sizes (one anne beets

* In. feng. and 75 broad, the others being respectively 2'o - in. and 2; in.
in sleneeis In eh of these the eye-spot is very nosinee and accom-
panied by a local ruggedness of the surface of the valve (not amount-
ing to a sulcus) ; the valves are faintly rimmed.

This black limestone is referred to the Trenton in Geol. Survey
Canada, Report, 1851-52, p. 73; but, according to a letter of ie
date from Sir W. E. Logan, it may be ee limestone.

* Beyrichia strangulata takes on a variety of forms (see Annals of Natural History
2nd series, vol. xvi. pl. 6, figs. 18-22) analogous to those of B. Logant.

94 CANADIAN FOSSILS.
d. Var. PAUQUETTIANA.

Plate XI. Fig. 12.

A small specimen of brownish, fine-grained limestone (weathering
grey, and containing shells), from Pauquette’s Rapids, Allumette
Island, Ottawa River, contains one well-preserved brown coloured
valve (fig. 12), } inch long, 2, inch broad, much like the largest spe-
cimen from Louck’s Mill, but showing no marginal rim, and feeble
traces only of the eye-spot and its accompanying depression. In this
fragment of limestone (probably Trenton) smaller Entomostracous
bivalves abound (see p. 99 and 100).

Except in the relative size, the form of the eye-spot, and the
valve-margin (in which latter points one of these larger specimens
varies from the others), the two sets of specimens (the large and the
small) do not appear to disagree essentially, as far as my means of
examination at present enable me to judge. At the same time, as
we know that in some recent bivalved Entomostraca, different species
and even subgenera may present a great similarity in their carapaces,
it is possible that we have here a distinct specific form.

Mr. Conrad has briefly described,* under the name of Cytherina
fabulites, a bivalved Entomostracan, from the Trenton limestone of
Mineral Point, Wisconsin. This appears to be a Leperditia half an
inch in length, and therefore surpassing in size the specimens under
notice, to which it may be allied.

See Annals of Natural History, 3rd series, vol. i. p. 340, for
descriptions of this and the following variety.

e. Var. JOSEPHIANA.
Plate XI. Fig. 16.

A small specimen of grey Trenton limestone, from the east side of
St. Joseph’s Island, Lake Huron, containing a Bryozoon, and weath-
ering yellowish, bears a right valve of a Leperditia 2} inch long, and
13 inch broad; there is also a separate perfect carapace of the same
form (11 inch thick) from the same limestone. The valves are of a
light-brown color; the eye-spots are indistinct ; the radiate markings
of the muscle-spot are more visible on the left than on the right valve;
the overlapping ventral edge is neither straight, nor symmetrically
curved ; the general form of the lower half of the carapace is rounded

and bulky.

* Proceedings of the Philadelphia Academy, 1843, vol. i. p. 332.

CANADIAN FOSSILS. 95

This Trenton form, which I have termed L. Canadensis, var Joseph-
tana, may possibly be the same as Conrad’s L. fabulites ; if so, his name
has priority.

f- Var. ANTICOSTIANA.

Plate XI. Fig. 17.

A piece of light-grey limestone (of the upper portion of the Hudson
River group) from East Point, Anticosti, bears on its weathered sur-
face encrinital ossicles and eleven separate valves of a Leperditia of
different sizes ; there is besides a separate perfect carapace of the same
form, half an inch long, 12 inch broad, and 4, inch thick). These
specimens have a rather short hinge-line, a well-marked ocular
tubercle, anda muscle-spot visible only byits slightly darker tint. In
some instances these valves appear to have a peculiar delicacy of make
and substance; they slope rapidly from the central convexity; the
ends of the carapace are thin, and the overlapping part of the right
valve is distinctly central and neatly curved. This form differs from
that of St. Joseph’s in having a shorter hinge-line and a more promi-
nent eye-spot; in the apparent absence of external radii to the muscle-
spot: in the somewhat more delicate substance of the valves; in the
lesser thickness of the carapace, in its attenuated edges before and
behind, and in the symmetrical curvature of the overlapping ventral
edge.

This neatly shaped Leperditia from Anticosti more nearly resembles
its almost gigantic allies of Sweden* than do any other American
Leperditie that I have seen. Still it is not without good points of
relationship with L. Canadensis, and I have provisionally termed it
L. Canadensis, var, Anticostiana.

The St. Joseph's form more nearly resembles the large varieties of
Leperditia Canadensis (pl. xi. figs. 11 and 12) than do the Anticosti
specimens ; and as I did not feel authorized to separate specifically
the little Grenville varieties, that from Louck’s Mill, and that of
Allumette, neither can I at present regard these comparatively
large and well-grown specimens as belonging to another specific type.

Mr. Salter having lately favoured me with better specimens of
the Leperditia alta, from Wellington Straits, than I had previously
seen, | am enabled to point out, that though in size and general form
the Arctic L. alta much resembles the Leperditie from Louck’s Mill,
Pauquette’s Rapid, St. Joseph’s, and Anticosti, it has a thinner
shell, and a distinct muscular spot, with vascular radii; and further,

* Annals of Natural History, 2nd series, vol. xvii. p. 85, pl. 6.

96 CANADIAN FOSSILS.

it shows an inclination to vary extremely in the vertical dimensions
of the carapace, so that in the same hand specimen, some individuals
are ovate-oblong, and others narrow and pod-shaped. This habit of
variability of outline is not apparent in the Canadian Leperditie above
described.

Other localities in Canada are mentioned by Sir W. E. Logan and
Mr. Murray for Entomostraca—probably L. Canadensis or allied forms,
namely :—

Three miles above Lachine; in the Trenton limestone ? *

Indian Lorette near Quebec ; in the Birdseye limestone ? ¢

Three or four miles from Montreal, in a line a little west of north;
in the Birdseye limestone. f

Sheik’s Island, Cornwall,§; with Atrypa plena in the Oinens

Cornwall ; in the Trenton limestonell.

Lancaster ; in the Black River limestoneq.

Winchester; in the Trenton limestone**.

III. Lererpir1a ANNA, Jones.

Plate XI. Fig. 13.
(Annals of Natural History, 3d series, vol. i. p. 247, plate ix. fig. 18.)

Length }, breadth 3 inch.

Small, convex; ovate-oblong, somewhat narrower in front than
behind; the ventral curve nearly uniform ; hinge-line straight; dorsal
angles slightly truncate. Surface of valves most convex at the pos-
terior third; smooth, thickly punctate, each of the little shallow
circular pits having a minute central tubercle. Eye-spot distinct
and raised.

Locality and Formation.—Several valves of this neatly-pitted
Leperditia are present in a small hand-specimen of a hard dark
colored concretionary limestone, under the zone of Atrypa plena, and
belonging to the Calciferous Sandrock, from immediately behind
the village of St. Ann’stt, at the confluence of the Ottawa and St.
Lawrence. This is probably the oldest known species of the genus.

Collector.—Sir W. EK. Logan.

* Quarterly Journal Geological Society, vol. viii. p. 205.

.t Letter, Jan. 17, 1853. } Letter.
§ Geol. Sur. Canada, Report, 1851-52, p. 70.
|| Ibid. p. 70. 1 Ibid. p. 71. ** Ibid. 72.

tt Quart. Jour. Geol. Soe. loc. cit.; and Geol. Sur. Canada, Report, 1851-52, p. 16

CANADIAN FOSSILS. 97

IV. LEPERDITIA AMYGDALINA, Jones.

Plate XI. Figs. 18, 19.

(Annals of Natural History, 3d series, vol. i. page 341.)

Several specimens of a dark-grey limestone, from near L’Orignal,
are rich in separate valves of a handsome Leperditia, which at
first sight has much the aspect of Isochilina Ottawa; but it is
larger, blacker, and has a proportionally shorter hinge-line, the
hinder portion of the valves being boldly and obliquely rounded,
forming about one-third the length of the carapace; though the
valves have a marginal rim, this is only on the two ends, being
wanting below, where the middle third of the ventral border is
turned in, overlapping on the right, and overlapped on the left side.
The surface is smooth ; the eye-spot prominent, and accompanied by
a slight, irregular nuchal furrow ; muscle-spot indistinct. The cara- .
pace is 2, inch long, ¥, in. broad, and .3, in. thick, and most convex
at the anterior third.

Though numerous in the rock, the individuals are not massed
together in layers, as are the Isochiline at L’Orignal, Grenville, and
White Horse Rapids.

Locality and Formation—One mile west of L’Orignal, Chazy.

Collector —R. Bell.

Genus IsoCcHILINA*. Subgenus of LEPERDITIA.

Equivalve ; the margins of the valves meeting uniformly, not over-
lapping as in Leperditia; greatest convexity of the valves either
central or towards the anterior portion. Eye-tubercle present.
Muscular spot not distinct externally.

V. Leperpitia (Isocuinina) Orrawa, Jones.
Plate XI. Fig. 14.

(Annals of Natural History, 2d series, vol. i. p. 248, plate x. fig. 1.)

Length 1, breadth 3, inch.

Leperditia-like im outline, somewhat elongate, smooth; marginal
border distinct, frequently seen to be marked by a line of small,
distinct pits; eye-spot distinctly raised.

* Equal lip.
G

98 CANADIAN FOSSILS.

From the canal at Grenville. Gregarious; the separated valves
forming a thin layer about half an inch thick, in a dark-grey lime-
stone of the Calciferous Sandrock, a foot or two beneath the ‘ two-
foot limestone,” and traceable for some miles.

In several specimens of Leperditia rock from the Chazy lime-
stone near the N.W. corner of the township of L’Orignal, I have
recognized the Isochilina Ottawa, under similar conditions to those in
which it occurs at the Grenville canal, except that in one specimen
it is associated with a Modiolopsis-like shell. I have only to remark,
that when the shell is broken off, the casts of the valves show a
distinct muscle-spot (concave on the inner side of the valve) with
numerous radii.

Collectors-—Sir W. E. Logan, J. Richardson, R. Bell.

VI. LeprrpitiA (ISOCHILINA) GRACILIS, Jones.

Plate XI. Fig. 15.
(Annals of Natural History, 3d series, vol. i. p. 248, plate x. fig. 2.)

Length }, breadth ~, inch.

Carapace sub-rhomboidal, narrow and slender when compared with
the Leperditie proper ; anterior extremity obliquely rounded, with the
antero-dorsal angle produced, slightly obtuse; posterior extremity
rounded, with the postero-dorsal angle obliquely truncate. Ventral
curve uniform. Surface of valve convex centrally, black, shining,
smooth, sparsely punctate; the pitting partial often obscure, or
nearly obsolete. Depressed margin broad, in many specimens bearing
a row of rounded pits (about thirty-two), which are represented on
the inside of the rim by corresponding raised obtuse points.

Locality and Formation.—Gregarious ; in loose fragments of a black,
fine-grained foetid limestone from the White Horse Rapids, Isle
Jesus, referred, with doubt, to the Trenton limestone in the Quart.
Journ. Geol. Soc., vol. viii. p. 205, but to the Birdseye limestone in
a letter of later date from Sir W. E. Logan. The disunited valves
lie matted together, and sprinkled with minute iridescent crystals
of pyrites, in a thin layer or layers in the rock.

Collector.—Sir W. E. Logan.

Genus CYTHEROPSIS, M‘Coy.

This generic appellation is affixed to a bivalved Entomostracan
(figure 2, plate 1. L.) in the ‘Systematic Description of the British

CANADIAN FOSSILS. 99

Palzozoic Fossils in the Geological Museum of the University of
Cambridge,’ 1855, but neither the characters of the genus nor of
the fossil are described, owing probably to the author not having
had time to add this description to the great work referred to.

Cytheropsis appears to me to be a useful term for the distinction of
those palzeozoic Entomostraca that do not closely assimilate either to
Leperditia or Beyrichia, but much resemble in outline and size many
of the Cytheres of the existing seas, differing however from them in
sometimes having eye or muscle-spots, and other peculiar features,
such as a comparatively great thickness of the valves. Though based
chiefly on negative characters, this group may for the present be
conveniently referred to as being generic.

I have noticed several minute Entomostraca in the Silurian rocks
of Wales and Sweden, which may probably belong to this group.

VII. CyTHEROPSIS CONCINNA, Jones.
(Annals. of Natural History, 3d series, vol. i. p. 249, plate x. figs. 3, 4.)

Length ;,, breadth ;; inch.

Carapace subcylindrical, tapering anteriorly ; ends rounded ; back
straight ; dorsal angles slightly truncate ; ventral edge of right valve
overlapping that of the left. Surface smooth, shining, light-brown,
partially pitted. In some specimens a very slight marginal rim is
traceable.

Locality and Formation—Many specimens, both of double and
single. valves, in the Trenton? limestone of Pauquette’s Rapids,
Allumette Island, Ottawa River.

I have had some doubt whether this may not be the young of a
Leperditia ; but 1t has no eye-spot and is too narrow, young Leperditie
being proportionally broader than the adults.

Collector.—Sir W. E. Logan.

VIII. CyYTHEROPSIS SILIQUA, Jones.
(Annals of Natural History, 3d series, vol. i, p. 249, plate x. fig. 6.)
Length 7, breadth 3, inch.
Carapace-valves long, narrow, pod-like or skiff-shaped; ends acute, .
one much sharper and more tapering than the other ; dorsal edge long

and straight ; ventral edge convex ; one valve overlapping the other.
Smooth, shining, brown.

100 CANADIAN FOSSILS.

Two separate valves of this curious and rather obscure form (so
much resembling Bazrdia siliqua of the Chalk, and the recent B. Minna)
occurred in the limestone from Pauquette’s Rapids.

TX. CyTHEROPSIS RUGOSA, Jones.
(Annals of Natural History, 3d series, vol. i. p. 249, plate x. fig. 5.)
Length 3, breadth =. inch.

30?

Small, convex, subreniform, broad, rounded at both ends, the an-
terior one of which is smaller than the other. Coarsely sculptured with
broad shallow pits. One specimen, showing the two valves united,
and of a light-brown color, occurred with the many other Entomos-
traca in the small specimen of limestone from Pauquette’s Rapids.

Locality and Formation.—Pauquette’s Rapids.

Collector.—Sir W. E. Logan.

To give a general view of the distribution of the known species
and varieties of Bivalved Entomostraca in the Lower Paleozoic strata
of the United States, Canada, and Arctic America, the following
Table is appended :—

101

CANADIAN FOSSILS.

TABLE OF THE PALMOZOIC BIVALVED ENTOMOSTRACA OF NORTH AMERICA.A

Genera and Species.

—— sigillata, Jones ........
clathrata, Jones........
plagosa, Jones.......-.
Leperditia gibbera, Jones....
Arctica, Jones). 2... .05-
7. —— marginata, Keyserling ..

ate
2.
3.
4.
5.
6.

8. ——alta, Conrad........ «.

5a. gibbera, var. scalaris...
9. Beyrichia Maccoyiana, Jones .
10. Pennsylvanica, Jones...

11. Leperditia Pennsylvanica, Jones.
12. Beyrichia lata, Vanuxem.......
13. Isochilina cylindrica (?) Hall ..

20a.Leperditia Canadensis (var) .
14, Leperditia fabulites, Conrad .
15, Cytheropsis concinna, Jones .
16, —— siliqua, Jones..........
17, TUGOSA, JONES scree = eles
20a.Leperditia Canadensis (var.).

20a. (var.).
18. OVatH, JONES. . 23)... 5 vine
20a. Canadensis (var.)......

°

Beyrichi rugulifera, Jones.........+++:

Localities.

Beecher: lel aindesn Mone went ereet re

+ | Wellington Straits 2. 2c. .e.5. ce cee ©
Rupert’s Land (and Petschora Land).

Schoharie (and Wellington Straits) .

Williamsville and Pennsylvania .....
InGranlsiy bene Go6Gqu0c000 0000.

19. Isochilina gracilis, Jones.........0+....
20. Leperditia Canaden. (var. nana) Jones...
21. Beyrichia Logani, Jones............+6
22. Isochilina Ottawa, Jones...+.....+++5s
23. Leperditia amygdalina, Jones .........|L’Orignal, Grenville.............+++...-

24,

PAVING yet) OTE B nia atateyetneders efegar eaters feanis

Pennsylvania ....

Penmsyl VANIA, ereketeaiereteraerereercte

Oneida County, &c.........
Medina, &c. ....-...-.0eees
SATIELCOS tite cretecevect soe suet eterconens
AWAEOCMEING 6505 Sane5 5

eeeeee

Allumette Island, Ottawa.

St. Joseph’s Island .........
IPGrnehAhyanes oacucadgqu00n

.

Louck’s Mills, Canada........
Isle Jesus, Canada .............050.
Grand Isle, Grenville, & Hawkesbury.
Grenville and Hawkesbury..........
Grenville, Canada <2... 000 ccs. cece

.

°

.

e

New York Groups.

eC CC ee

J

; Coralline Limestone & Tentaculite Lime-

stone (Lower Helderberg) ...........
Wisiterlinme) torepayerverclonmtenetcreteyetertetonsteret=

k Onondaga Salt-group.

; Clinton group.......

-|Medina Sandstone.....
-|Hudson River group..
-|Trenton Limestone...

f Trenton Limestone.

J

Blackriver Limestone.
; Birdseye Limestone

ee Limestone ..

British
groups.
od
EF
52
B oo
ed
aE
as
oO
B
oO -
8s
ae
3 6
=—
|
oo
a 5
rg
oO
co 2
Aro
as
Hs
o

St. Ann, Canada..........eceeeeesneeees(Calciferous Sandrock......cssseeessevee! J

Two other forms of Entomostraca, with which I am as yet unacquainted, are described 'by Prof. J. Hall; namely Cytherina spinosa, Pal.
New York, vol. ii. p. 317, pl. 67, fig. 17-21, and Beyrichia symmetrica, loc. cit. f. 16, from the Niagara Shale, Lockport. Hall also mentions
and figures another form (op. cit. vol. i. p. 44, pl. 10, f. 12) from the Birdseye Limestone and Trenton Limestone.

102

Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.

Fig.

Fig.
Fig.

Fig.

Fig.

Fig.
Fig.
Fig.
Fig.
Fig.
Fig.

Fig.

10.

12.

13.

14.

15.

16.

1Y.

18.

19.

CANADIAN FOSSILS.

EXPLANATION OF Figures. Plate XI.

B. Logani (var. reniformis) ; magnified 4 times: a, right valve ; b, dorsal view ;

B.

B

B.

B.

c, anterior view. From Hawkesbury.
Logani; magnified 4 times: a, left valve ; 6, dorsal, and c, posterior view.
From Hawkesbury.

. Logani ; magnified 4 times: a, left valve ; 6, ventral, and c, posterior view.

From Grenville.

Logani; magnified 4 times: a, right valve; 6, dorsal view. From
Hawkesbury.

Logani (var. leperditoides) ; magnified 4 times: a, right valve; 6, anterior
view. From Grenville.

Leperditia Canadensis (var. nana); magnified 4 times: a, left valve; 6, ven-

L.

L.

L.

tral, and c, posterior view. From Grenville.

Canadensis (var. nana) ; magnified 4 times: a, right valve; 6, ventral view.
From Grenville.

Canadensis (var. labrosa): magnified 4 times: a, left valve; b, ventral,
and c, anterior view; d, portion of surface of a, very highly magnified
(x 75).

. Canadensis (var. nana) ; magnified 4 times: a, left valve; b, dorsal, and c,

anterior view. From Grande Isle.

. Canadensis (var. nana) ; dorsal view of the united valves (nearly closed) ;

magnified 4 times. From Grande Isle.

. Canadensis (var. Louckiana); a, right valve, magnified 2 diameters ;

b, ventral view; c, anterior view; d, outline, magnified 4 times. From
Louck’s Mill. ,

. Canadensis (var. Pauquettiana): a, right valve, magnified 2 diameters ;

b, the ventral, and c, the anterior view, showing the inner flange of the
ventral edge; d, outline, magnified 4 times. From Pauquette’s Rapids,
Allumette Island.

Anna ; magnified 4 times: a, right valve ; b, ventral, and c, anterior view ;
d, portion of surface of a, highly magnified (x 25). From St. Anne’s.

Isochilina Ottawa ; magnified 4 times: a, left valve; b, anterior, and c, ventral

view. From Grenville Canal.

I. gracilis ; magnified 4 times: a, right valve ; b, anterior view, and c, ventral ;

L.

L.

d, magnified portion of the marginal rim. From White Horse Rapids.
Canadensis (var. Josephiana) ; natural size: a, right valve ; b, ventral, and
c, anterior view. From St. Joseph’s Island.

Canadensis (var. Anticostiana) ; natural size : a, left valve; b, ventral view.
From Anticosti.

. amygdalina ; natural size: a, right valve; 6, ventral, and c, anterior view.

From L’Orignal.

. amygdalina ; natural size: a, left valve; 6, ventral, and c, anterior view

From L’Orignal.

PLATE I.

PLEUROCYSTITES SQUAMOSUS (page 49).

Figures la and 1b. Dorsal views of two specimens.
‘© ce. Ventral view of a specimen, shewing the plated integument and strong
borders formed by the folding over of the dorsal plates; 0, the mouth.
“ 1d. Ventral view of the upper part of the cup and arms of a specimen of this
species, the remainder of which is completely buried in the stone.
“© le. View of the same, enlarged; at ais the small sub-apical aperture. It is

represented too large in the figure.

PLEUROCYSTITES ROBUSTUS (page 49).

Figure 2a shews a fragment of the upper part of a specimen. From the position in
which the artist viewed the specimen, the left rhomb in the figure appears

too angular on the upper side.

PLEUROCYSTITES ANTICOSTIENSIS (page 52).

Figure 3. Dorsal view of an imperfect specimen of this species.

myer cd
a a * f
Pits gh ok BAL

‘ ¥ 4 ”
wo Weir Lastery - 4

PLALE II.

PLEUROCYSTITES FILITEXTUS (page 50).

Figure 1a is a specimen which has the column and a portion of the arms firmly attached
to a piece of limestone. The greater part of the body however is loose,
and can be removed in one piece, giving a view of the ventral side.

‘‘ 10 is the ventral side, shewing the large plates of the integument, and obscurely
the small aperture near the apex. The specimen is somewhat distorted
by pressure, so that the true form of the rhombs cannot be made out.
0, the mouth.

PLEUROCYSTITES ELEGANS (page 51).

Figures 2a, 2b, 2c, and 2d? are dorsal views of this species. It is doubtful whether 2d
should be referred to this species or to the thickly striated varieties of
P. filitextus. The crushed condition of this, and indeed of all the speci-
mens, renders it most difficult to decide when the species are so closely
allied.

fi

*

DECADE 3.P1 3
GEOLOGICAL SWIRWEY OF CAWADA . LOWER SILURIAN
Trenton

Tuffen West del.etlith West & C° imp

PLATE Ii.

GLYPTOCYSTITES MULTIPORUS (page 54).

Figure la. The plates of the calyx spread out; the dotted lines which extend from
the top to the bottom indicate the course of the arms.

“ 1b. Plates of the genus Echino-encrinites, figured here for comparison.

“¢ d. Anterior view of a perfect specimen of G. multiporus.

‘EH. The left side of the same specimen.

« F. The dorsal or posterior side of another specimen.

“ ¢. The right side.

“ g. The apex, enlarged.

«i. The base.

* =n. A specimen with the column attached; anterior view.

« L. One of the rhombs enlarged.

“ gandk. Sections shewing the depth to which the partitions of the rhombs

entered.

(Tren ton.)

as
ae
Coll
Hu
a a
O
As
Pa

Sa

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|
|

=

SSS

SSS

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West & C

os ep

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Tuffen West, del et lith

PLATE IV.

GuiyprocystiTEs Locant (page 57).

Figures la and 10 are dorsal views of two specimens.

cc

1c, 1d and le are enlarged views of the interiors of three rhombiferous plates,
shewing that the pores penetrate through, and that each on the inside
is surrounded by an exceedingly thin elevated border.

1f. <A portion of the ambulacral groove of the apex, and one of the pinnulz
enlarged.

lg. <A fragment with two of the pinnule.

li and 1j. Fragments of columns. The specimens are crushed, and do not

clearly shew the spiral arrangement.

G. LOGANI, var. GRACILIS (page 59).

Figure 2. Dorsal side of the only specimen collected.

GLYPTOCYSTITES FoRBESI (page 59).

Figures 3a and 3b. Two views of the base of a specimen.

“¢ 3c and 3d. Imperfect plates, to shew the character of the rhombs.
«3d has the remains of four rhombs.

‘* 3e is the basal plate of the right side.

¢ 3f is the hexagonal basal plate of the anterior side.

«3g and 3h, round columns, with the edges of the large joints pitted.

nea tiy itty

DL OTE

ie ogek 93) 39 SITET ON RANE tiga i, sa ;

W125 iy Ns sion, iwagalay id sega a he Dias Maia aah, }
* ult qyet io sesh ia oft baat ¥ a hy
6h idyi ol? Wot anwiig Og ce ui |
bia ayiioina ant w adistig feast Coates im th ai: 8

‘hvala wi ati Of sites l st To sabe in ditt SEE hes Soi eh

Gig OLOGICAL SUIRVIEY OF CANADA.

DE CADE 3. P15.
LOWER SILURIAN
(Frenton_)

Roeeihon eR OPT

Horace S, Smith, del. et ith

Prnted by Hullmandel&Walton.

PLATE V.

CoOMAROCYSTITES PUNCTATUS (page 61).

Figure 1. Anterior view of a large specimen, with one arm and the pinnule attached.

o, the mouth.

« la. A plate of the same, enlarged, to shew the peculiar striation.

* 10. The valvular apparatus of the mouth, enlarged.

«2. View of the left side of another specimen.

“2a. A plate of same, enlarged.

¢ 26. Outline of the summit, shewing the positions of the bases of the arms, and
the ambulacral groove between them.

Dr. E. Van Cortlandt of Ottawa, has kindly sent me from his cabinet two of the best
specimens of C. punctatus that I have yet seen, both of which have the mouth furnished
_ with six valves instead of five, and it thus appears that the number is variable as it is
in the Crinoid Caryocrinus ornatus (Say). Where the plates are very perfect they are
striated in the manner represented by fig. 2a, and the ridges between the plates are quite
sharp and imperforate. It is probable, therefore, that in no case are the pores visible
externally, unless where the surface is worn. This latter fact, first clearly exhibited by
Dr. Van Cortlandt’s specimens, shews that Camarocystites and Paleocystites are closely
allied genera.

These specimens did not reach me until after the foregoing sheets had been printed,
otherwise they would have been noticed in the body of the work.

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fio wade be, iki add ab Await sie rd formal ipa

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f 0 Woe,

i

n rn DECADE 3P1 6.
GE OLOGICAL SURVEY OF CANADA. LOWER SILURIAN.

(Trenton.)

Horace S-. Srmith, del.et ith Printed by Hulhnandel&Waiton.
Lithog™* to the War Department

Figure la.
Hs Ways
Hah lice
a lah
aerate

PLATE VI.

AMYGDALOCYSTITES FLOREALIS (page 63).

The left side of a specimen; m, the mouth.
Right side of the same.

Posterior view.

Anterior views. The groove is not clearly shown in this specimen.
One of the plates enlarged.

AMYGDALOCYSTITES TENUISTRIATUS (page 64).

Figures 2a, 2b. Right and left side of the Ottawa specimen; m, the mouth.

BG) BBs

Hey 2

Figure 3a.
Us Sls

Left side of a specimen from Belleville, shewing a portion of the arm.

The arm enlarged, shewing the ambulacral groove.

View of the top of the arm, shewing the articulating cavities of the pin-
nule, and the branches of the ambulacral grooves leading to them.

A plate enlarged, shewing the strie.

AMYGDALOCYSTITES RADIATUS (page 65).

A specimen crushed flat, imbedded in stone.

One of the plates enlarged. The specimen is worn, and does not shew the

granular surface of the spaces between the radiating ridges.

Mca. a8

Maer Ch ar

s bain: A
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MOR IETS 2 ie hy aaah rei

my . i
, Lila ' ute sat
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Ly Gober a, nat i.

cli a
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Qs

mi ie

DECADE 3.P1. 7.

GEOLOGICAL SURVEY OF CANADA. LOWER SILURIAN
(Chazy-)

Horace S. Smith,del.et th ‘Primted by Hullmandel & Walton.
Lithog™® to the War Department

Figure la.

ales

CONC:
tc ld,
Cife

Clin:

WO vals

Figure 2a.
co 20:
a 19K
UG Hike

PLATE VIi.

MaocystitEs Murcuisoni (page 66).

Right side of a specimen, shewing the ambulacral orifice and the eight arms.
The left side, shewing the position of the mouth, m.
Vertical view of the ambulacral orifice.
le. Left sides of two other specimens.
Apex of le.
Base of 1d, shewing the three basal plates.
Portion of an upper surface of an arm magnified.

MALocysTITES BARRANDI (page 67).

View of the left side of a specimen; a, the arm.

Posterior view of the same.

Anterior view of another specimen.

The arm of 2a magnified, shewing the short branches of the ambulacral
furrow to the bases of the pinnule.

DECADE 3. P1.8.

GEOLOGICAL SWIRVWIEW OF CANADA. LOWER SILURIAN
( Trenton )

C.R Bone, del et ith Prmted by Hulhnandel&Walton.

PLATE VIII.

EDRIOASTER Biespyr (page 82).

4

Figure 1. Upper side of a specimen partly embedded in stone.
Dehetre, A polished section through the mouth and two of the grooves, showing that
the pores penetrate through.
‘« 2, Fragment of a crushed specimen, showing two of the rays.
“2a. A portion of figure 2 enlarged to show the pores.

AGELACRINITES Dicksont (page 84).

Figure 4. The original specimen discovered by Dr. Bigsby, now in the Museum of
Practical Geology, Jermyn Street, London.
“« 4a. The same enlarged.
“ 3. View of a different specimen, in collection Geological Survey of Canada.

(3a. The same enlarged.

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DECADE 3. P1.9-
LOWER SILURIAN.
(Trenton & H. RJ

Tuffen West, del et lith West & C° imp.

PLATE 1X.

PALASTERINA STELLATA (page 76).

Figure la. The specimen natural size.

‘1b. The same enlarged.

PALASTERINA RUGOSA (page 77).

Figure 2a. Dorsal view of a specimen from the Hudson River group, Anticosti.
«2b. Fragment of another individual.
“* 2c. One of the plates enlarged.

PETRASTER RIGIDUS (page 80).

Figure 3a. Ventral view of an imperfect specimen.
Fig. 3a appears to be the dorsal side of an individual of this species with the plates
along the centre of the rays removed.

a

‘pa pu wad
Mir ey Lary
“ 4

DECADE 3. P10.

EOLOGICAIL SWIRWIEY OF CANAIDA. LOWER. SILURIAN.

Tuffen West, del et lith. West & C® imp.

PLATE X.

STENASTER SALTERI (page 78).

Figure la. Ventral view of a specimen collected at Belleville.
1b. The same enlarged.

STENASTER PULCHELLUS (page 79).

Figure 2. Ventral view of the only specimen collected.

TANIASTER SPINOSUS (page 81).

Figure 3a. Ventral view of a small specimen.
« 3b. The same enlarged.
“ 3c. Another specimen, with the rays bent upwards.

“3d. The same enlarged.

TZNIASTER CYLINDRICUS (page 81).

Figure 4a. Dorsal view of a specimen.
‘ 4b. Ventral view of a different specimen.

f i i
j ‘ah
vette gin

Tall
ne

anit
VOT Vite
ane Ae

ey

DECADE 3.P1.10 tas
GEOLOGICAL SURVEY OF CANADA. LOWER SILURIAN

(Trenton)

J.De C.S.and JW Salter del. J.De C. Sowerby. se.

PLATE X. (bis.)

CYCLOCYSTOIDES HALL (page 86).

Figure 1. Impression of the marginal plates in a fragment of limestone.

“ 2. A different specimen, shewing twenty-six of the marginal plates.
the tube.

OD Hw

2d*, tube enlarged. 2*, marginal plates enlarged.

Marginal plates enlarged.

A portion of the dise enlarged.

A small specimen nearly perfect. 5*, portion of margin enlarged.
Portion of a specimen partly destroyed by the application of acid.
Pari of 6 enlarged.

CycLocysToIpES Davisit (page 89).

Figure 8. Cast of a specimen with margin perfect.
i 9. Portion of margin magnified.
“ 10. Ideal section of Cyclocystoides.
« 11. Pentagonal Star-fish.
“ 12. Amygdalocystites florealis.
& 12. Pseudocrinites magnificus.

The three latter figures are given for comparison.

cand b,

> aa

i,

DECADE .3. PL11
LOWER SILURIAN.

GCEOLOGICAL SURVEY OF CAWADA.

/¢ 2a Be 42 Ze

{ 3b \ /
See ae, —— — (
72 2b 4? 56

17 TS TES: 19 Ug

Geo.West del. & lith West & C? imp.

Fig.
Fig.
Fig.
Fig.
Fig.
Fig.
Fig.

Fig.

Fig.
Fig.

‘Fig.

Fig.

Fig.

Fig.

Fig.
Fig.
Fig.
Fig.

Fig.

10.

12.

13.
14.
15.
16.
17.
18.

19.

B.

B.

PLATE XI.

(Page 91—102.)

. Logani (var. reniformis) ; magnified 4 times: a, right valve ; 6, dorsal view ;

c, anterior view. From Hawkesbury.

. Logani ; magnified 4 times: a, left valve; b, dorsal, and c, posterior view.

From Hawkesbury.

. Logani ; magnified 4 times: a, left valve ; 6, ventral, and c, posterior view.

From Grenville.

Logani ; magnified 4 times: a, right valve; 6, dorsal view. From
Hawkesbury.

Logani (var. lepeditoides) ; magnified 4 times: a, right valve; 6, anterior
view. From Grenville.

Leperditia Canadensis (var. nana) ; magnified 4 times: a, left valve; 0, ven-

L.

L.

tral, and c, posterior view. From Grenville.

Canadensis (var. nana) ; magnified 4 times: a, right valve ; 6, ventral view.
From Grenville.

Canadensis (var. labrosa); magnified 4 times: a, left valve; 6, ventral,
and c, anterior view; d, portion of surface of a, very highly magnified

(x 75).

. Canadensis (var. nana) ; magnified 4 times: a, left valve ; 6, dorsal, and c,

anterior view. From Grande Isle.

. Canadensis (var. nana) ; dorsal view of the united valves (nearly cloeed) ;

magnified 4 times. From Grande Isle.

. Canadensis (var. Louckiana); a, right valve, magnified two diameters ;

b, ventral view ; c, anterior view; d, outline, magnified 4 times. From

* Louck’s Mill.

. Canadensis (var. Pauquettiana) ; a, right valve, magnified 2 diameters ;

b, the ventral, and c, the anterior view, showing the inner flange of the
ventral edge; d, outline, magnified 4 times. From Pauquette’s Rapids,
Allumette Island.

L. Anna; magnified 4 times: a, right value; 6, ventral, and c, anterior view ;

d, portion of surface of a, highly magnified (x 25). From St. Anne’s.

Isochilina Ottawa; magnified 4 times: a, left valve; 6, anterior, andc, ventral

view. From Grenville Canal.

I. gracilis ; magnified 4 times. a, right valve ; b, anterior view, and c, ventral ,

L.

L.

d, magnified portion of the marginal rim. From White Horse Rapids.
Canadensis (var. Josephiana) ; natural size: a, right valve; b, ventral, and
c, anterior view. From St. Joseph’s Island.

Canadensis (var. Aniicostiana) ; natural size : a, left valve ; 6, ventral view.
From Anticosti.

. amygdalina; natural size: a, right valve; 6, ventral, and c, anterior view.

From L’Orignal.

. amygdalina ; natural size: a, left valve ; b, ventral, and c, anterior view.

From L’Orignal.

ies {Quy 4

. et 47
A