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.<5!h£j?^'

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^a^i£S

Stbrarg of Ifjs glitscum

OF

COMPARATIVE ZOOLOGY,

AT HARVARD COLLEGE, CAMBRIDGE. MASS.
jfovm^ei hS prfbate siibscnptfon.Jn 1861.

I 1

Deposited by ALEX. AGASSIZ.

No. Q7QY ^

"TABULATE CORALS"

PALEOZOIC PERIOD

ON THE

STRUCTURE AND AFFINITIES

OF THE

TABULATE CORALS"

OF THE

PALEOZOIC PERIOD

WITH CRITICAL DESCRIPTIONS OF
ILLUSTRATIVE SPECIES

BY

H. ALLEYNE NICHOLSON

M.l)., D.Sc, F.R.S.E., F.L.S.

riJOFKSSOR OF NATUKAL HISTORY IN THE
U.NTVKKSITY OV ST ANDREWS

WILLIAM BLACKWOOD AND SONS

EDINBURGH AND LONDON

MDCCCLXXIX

TO

J. N.

IX GRATEFUL ACKNOWLEDGMENT

OF IMMEMORIAL LOVE, OF PRICELESS COUNSEL,

AND OF UNFAILING HELP,

E|)is moxk

IS AFFECTIONATELY INSCRIBED BY
THE AUTHOR.

P REPACK.

The present work is a record of a series of researches which I
have been engaged in carrying out, with intermissions, for some
years, into the minute structure and relations of the Palaeozoic
" Tabulate Corals." The space, means of illustration, and
leisure at my command have not permitted me to make this an
even approximately exhaustive account of the numerous and
interesting forms of Corals embraced by Milne- Edwards and
Jules Haime, under the name of " Zoantharia Tabulata." I
have, therefore, restricted myself, in the meanwhile, to the
elucidation of the anatomy of the principal Palaeozoic genera of
the " Tabulata," which I have been able to personally investi-
gate ; and I have usually given in addition short descriptions
of one or more of the species of each genus, as illustrative of
the structural type under consideration.

The general result of my investigations is that I am able
to corroborate the views of Verrill and Lindstrom as to the
necessity of abolishing the "Tabulata" as a distinct and
separate division of the Zoa^itharia. I have also been led to
conclude that under the old name of "Tabulata" there are
included at least twelve distinct groups of corals, and that,
while some of these are Hvdropsoa, and others are true Zoan-

viii PREFACE.

iharia, a large number may be referred, with greater or less
certainty, to the order of the Alcyonaria — a few forms being of
quite uncertain affinities. I have not, however, been induced
to think that the so-called " Tabulate Corals " are, to any
extent, referable to the Polyzoa ; ^ and I do not think that any
but the aberrant MilleporidcB can be at present regarded as
possessing Hydrozoan affinities. On many minor points I
have been led to form conclusions different from those that are
ordinarily held, and I have no right to expect that these will
be in all cases immediately or generally accepted ; while I
have the certainty that many of the results which I have

^ Since this work has passed through the press, Professor Busk has published a
description and figures of the recent species of Heteropora referred to on p. 256,
giving to it the name of H. Neozelanica (Journ. Linn. Soc, vol. xiv., p. 724). Two
other living species have also been described by Mr W. Waters (Journ. Roy. Mic
Soc, June 1879). Mr Busk has shown that the walls of the zooecia and interstitial
tubes (" cancelli ") of H. Neozelanica are perforated by minute pores, a phenomenon
not unknown in species of the genus now extinct. In the comparatively limited
investigation of//'. Neozelanica made by me, these pores escaped notice. The con-
necting-pores just alluded to certainly admit of a comparison with the "mural
pores" of the Favositidce, but the comparison is not much closer in their case than
in the instance of the pores in the walls of species of Lepralia or Alecto. Nor does
their similar appearance and position prove these apertures to be absolutely homo-
logous. At any rate the likeness between the pores of Heteropora and the mural
pores of the FavositidcE is, to say the very least, no closer than the resemblance
between the latter and the apertures in the walls of such undoubted Actinozoa as
Porites and Alveopora. Giving due weight to this last consideration, and combining
this with the fact that the true zooecia oi Heteropora do not appear to be "tabulate,"
while the typical " Tabulata" exhibit so many and such important points of affinity
with unquestionable living corals, both Alcyonarians and Zoantharians, I do not at
present feel inclined to alter the opinion which I have formed as to the Ccelenterate
nature of the FavositidcB, the ChstetidcE, and the Monticidiporidce. At the same
time, it is undeniable that there is a remarkably close resemblance between some of
these forms (and especially the Monticuliporoids) and Heteropora. This resemblance
is enhanced by the fact that one of the species of Heteropora described by Mr
Waters exhibits the usually chitinous surface-pellicle in a calcified and thickened
condition, thus reminding us forcibly of the state of parts in some of the species of
Favosites, and in various of the Monticuliporidcc. These resemblances, as above
pointed out, are counterbalanced by weighty points of dissimilarity; but they are
more than sufficient to make us await with the greatest interest any observations
upon the ajii/nal of Heteropora.

PREFACE. ix

obtained will not be arrived at except by those who are willing
to adopt the modes of investigation here followed. ^

To those acquainted with the subject, it is unnecessary for
me to point out that I have been greatly assisted in the task I
have attempted by the previous labours of Milne- Edwards and
Haime, Martin Duncan, Lindstrom, and other distinguished
palaeontologists, and especially by the investigations of Louis
Agassiz, Verrill, and Moseley into the structure and relations
of the few existing Tabulate Corals. At the same time, almost
all the actual facts recorded in this volume have been verified
or worked out by myself, and any facts which I have not per-
sonally been able to test are invariably accredited to their
original authority.

In this connection I should further add that I have not
been able to refer to the fifth volume of the ' Palaeontology of
New York,' by Professor James Hall, which, I believe, con-
tains numerous illustrations of Palaeozoic Tabulate Corals ;
the cause of my inability to consult this important work being
that, after repeated attempts, I found it impossible to obtain a
copy through the ordinary channels. Under these circum-
stances I can only leave it to my fellow workers to decide how
far a scientific work, which apparently cannot be obtained by
purchase, is to be regarded as actually published ; and in
making this remark I need hardly say that I am merely
anxious to account for an apparent omission on my part,
and do not wish to express any opinion upon the method in
which Professor Hall has seen fit to bring out his work.^

1 In this connection I may specially refer the reader to the remarks made at p.
270 as to the proper method of sectioning the coralla of the Tabulate Corals, with a
view to microscopic examination.

"^ The work here referred to appeared, I believe, in 1877. With regard to its
publication, Professor C. A. White states (Bibliography of N. Amer., Invert. Pal., p.
38, 1878^ that he had been unable to consult a copy, "search for it in the libraries
of Washington and Philadelphia having been unsuccessful." He adds : " Only one
hundred copies are reported to have been published."

X PREFACE.

The material upon which this work is based is principally,
though not exclusively, contained in the extensive collections
of Corals which I have made from the Palaeozoic formations
of Britain, the Continent of Europe, and North America; but
I have also had the opportunity of consulting the collections of
the British Museum, the Museum of Practical Geology, and
the Edinburgh Museum of Science and Art. The method of
investigation which I have adopted has been largely that of
microscopic sections, and the present work is, therefore, much
more extensively occupied with detailed descriptions of minute
structure than has been usual in treatises or memoirs dealing
with the fossil Corals. For the same reason I have been more
concerned to investigate the actual anatomy and systematic
relations of even perfectly well known types, than to describe
new forms or to discuss difficult and disputed points of specific
determination. The necessary sections, wuth few exceptions,
have been personally prepared by myself, and the illustrations
of microscopic structure are from drawings made by the
camera lucida. Unless otherwise explicitly acknowledged,
all the illustrations, whether in the text or the plates, are from
original drawings of my own ; and I have to return my best
thanks to my friend Mr Berjeau for the care and fidelity with
which he has reproduced these on wood and stone.

I have, finally, to express my gratitude for the varied and
valuable assistance which has been freely accorded to me by
my friends Mr R. Etheridge, F.R.S., Mr R. Etheridge, jun.,
F.G.S., Mr George Jennings Hinde, F.G.S., Dr Gustav
Lindstrom, and Dr Ramsay H. Traquair, F.R.S.E.

United College, St Andrews,
September \o, 1879.

LIST OF ILLUSTRATIONS.

ENGRAVINGS.

FIG.

1. Millcpora alciconiis, Forsk.,

2. The animal of Millepora nodosa. (After Moseley),

3. PocUlopora aspcra, var. lata, Verrill. (After Dana),

4. Favositcs favosa, Goldf. ; and F. Gothlandica, Lam.,

5. Syringopora rct'ifonnis, Bill. (After Billings),

6. „ vcrticillata, Goldf. (After Billings), .

7. „ Dalmani, Bill. (After Billings),

8. Aulopora tiibceforiiiis, Goldf. ; and CladocJwniis {Fyfgia) Micliclini.

Edw. and H. (After Goldfuss, and Edwards and Hainie),

9. Halysitcs catcnularia, Linn. ; and H. agglomcrata, Hall. (Origi?ial)

10. Tdradiuui mi?ius, Safford. (Original), ...

11. Heliolitcs incgastoma, M'Coy. (Original), .

12. LabecJiia avifcrta, Edw. and H. (Original),

13. Alvcopora spongiosa, Dana. (After Dana),

14. Yorxn?, oi Favosifcs Gof/iIandica,l^'^Vi'\. (Original),

15. Favosites hemispherica, Yand. and Shum. (After Billings),

16. Pachypora Fischer i, Bill. (Original),

17. Pachypora frondosa, Nich. (Original),

18. Striatopora flexHosa, Hall. (After Hall), .

19. Romingeria nvibcllifera, Bill. (Original), .

20. Calices of Alveolites suborhicnlaris, Lam. (After Goldfuss),

21. Michelinia convexa, D'Orb. (After Billings),

22. Plcurodictyiiin problanatiann, Goldf. (After Roemer, and Edwards

and Haime); and P. stylophoriiin, Eaton. (Original), .

23. Diagrams of Sections of Favosites and Pleiirodictyuiu. (Original),

24. Sections oi Araopora australis, Nich. and Eth., jun. (Original),

25. Stenopora Jackii, Nich. and Eth., jun. (Original),

26. Sections of Stenopora ovata, Lonsd. (Original), .

PAGE

14

IS
16
18
18
18

30

22

23
26
28
32
48
67

93
95
98

1^5

127

140

145
149

167

173
174

LIST OF ILLUSTRATIONS.

27. Syringoilies Hiifonensis, lim^Q. (Original),

28. Colunmaria calicina, Nich. (Original),

29. „ (?) Halli, Nich. (After Billings),

30. Sections of Syri/igopora reticulata, Goldf (Original),

31. Cladochoniis Michetini, Edw. and H.; and species of Aulopora

(Original), ......

32. Monilopora ct-assa, M'Coy, sp. (Original),
2,2^. Tetradiiwi minus, Safiford. (Original),

34. Heteropora Neozelanica, Busk (Original); and H. suhretiailata

(After Reuss), ......

35. Sections oi Monticidipora and Ch(ztetes. (Original),

36. Monticulipora moniliformis, Nich. (Original),

37. ^QCtxon oi Monticulipot-a moniliformis, l>i\c\\. (Original), .

38. ^Qciions oi Stenopora Tasmaniensis, honsd. (Original), .

39. Sections of Fistulipora minor, M'Coy. (Original),

40. Fistulipora incrassata, Nich. (Original), .

41. Sections oi Fistulipora proporoides, Nich. (Original),

42. Monticulipora {Diplotrypa) Whiteavesii, Nich. (Original),

43. Prasopora Grayce, Nich. and Eth., jun. (Original),

44. Labechia conferta, Edw. and H. (Original),

179
198
201
211

220
224
233

257
274
279
279
281
307
309
311
317
325
331

PLATES.

I. Favosites Gothlandica, Lam.; and F. Fo?'besi, Edw. and H.

IL ,, Forbesi, Edw. and H.; and its varieties.

III. „ Forbesi, Y.d\\\ dJCid. H. ; F. hemisp/ier ica, Ysirxd. and Shum.; and

F. Bowerbanki, Edw. and H.

IV. ,, clausus, Rom.; and species of /'^/(f/^j'/'^rd;.

V. Species of Pachypora, Striatopora, and Trachypora.

VI. ,, Vermipora, Alveolites, and Coenites.

VIL „ Cxnites, Columnopora, and Laceripora.

VIII. ,, Pleurodictyujn, Chonostegites, and Lyopora.

IX. ,, Stenopora, Lyopora, Nyctopora, and Billingsia.

X. ,, Colunmaria, Syringopora, and Haly sites.

XL „ Halysites, Thecia, Propora, Lyellia, and Plasmopora.

XII. ,, Plasmopora, Heliolites, Pinacopora, and ChcBtetes.

XIII. ,, Monticulipora [Heterotrypa, Diplotrypa, and Monottypa).

XIV. ,, Monticulipora (^Diplotrypa and Monotrypd), and Constcllaria.
XV. ,, Dekayia, Fistulipora, and Labechia.

PALEOZOIC TABULATE CORALS.

CHAPTER I.

THE CLASSIFICATION AND AFFINITIES OF THE " TABULATE

CORALS."

The " Tabulata',' as originally understood, constitute one of
the four primary divisions of the Zoantharian Actinbzoa, as
laid down and defined by Milne- Edwards and Haime in their
great works upon the fossil Corals (Brit. Foss. Corals, Intro-
duction, 1850; and Polypiers Foss. des Terr. Pal., 1851). In
this division was included a larcre assembla8;-e of Corals, rancrlne
from the Silurian period to the present day, and often of very
diverse structure, but characterised by the possession of well-
developed " walls," by the separation of the visceral cavities
of the corallites into distinct chambers by transverse partitions
or " tabulae," and by the rudimentary condition of the " septa."
The distinguished French zoophytologists just quoted remark
of this division of the Corals, that its principal character " is
founded on the existence of the lamellar diaphragms that close
the visceral chamber of the corallites at different heights, and
differ from the dissepiments of the Asti'ceidcE by not being
dependent on the septa, and forming as many complete hori-
zontal divisions extendinfy from side to side of the general

2 TABULATE CORALS.

cavity, instead of occupying only the one or two loculi. It is
also to be remembered that the septal apparatus, though more
or less rudimentary, has the same general mode of arrangement
as in the preceding sub-orders " {Aporosa and Perforata), " and
never presents the crucial character which we shall find in the
Zoantharia Riigosa!' They also divide the " TabiUata " into
the following four families, comprising the under-mentioned

Fani. I. MiLLEPORiD^. — Corallum principally composed of a very abundant

coenenchyma, distinct from the walls of the corallites, and of a tubular or

cellular structure. Septa not numerous ; tabulae numerous and well formed.

Gex\Qx:x—Mi/kponi, Lam.; LLeliopora, De Blainv. ; LLeliolites, Dana; Fistiili-

. pora, M'Coy ; Plasmopora, Edw. and H,; Fropom, Edw. and H. ; Axopora,

Edw. and H. ; Lobopora, Edw. and H.
Fam. II. Favositid/E. — Corallum essentially formed by lamellar walls, with
little or no coenenchyma. Visceral chambers divided by numerous and
well-developed complete tabular.

Tribe i. Favosithnc. — Corallum massive. Walls perforated. Septa rudi-
mentary. No coenenchyma. Genera — Favositcs, Lam. ; Michelinia,
De Kon. ; Koninckia, Edw. and H. ; Alveolites, Lam.
Tribe 2. Chcetetince. — Corallum massive. Walls not perforated. Neither
septa nor coenenchyma. Genera — Chcetetes, Fischer; Dania, Edw.
and H ; Ste/iopora, Lonsd. ; and Constellaria, Dana.
Tribe 3. ILalysitincE. — Corallum composed of corallites constituting verti-
cal laminae or fasciculi, but more or less free laterally, and united by
means of connecting tubes or mural expansions. Walls well developed,
and not porous. Septa distinct, but small. Genera — Balysites,
Fischer; Harmodites, Fischer (subsequently abandoned for Syringo-
pora, Goldf.), and T/iecostegites, Edw. and H.
Ti-ibe 4. PocilloporincB. — Corallum massive, gibbous, or subdendroid,
with thick imperforated walls, forming towards the surface an abun-
dant compact coenenchyma. Septa quite rudimentary. Genus —
Pocillopora, Lam.
Fam. III. Seriatoporid^. — Corallum arborescent or bushy, with an abun-
dant compact coenenchyma. Visceral chambers filling up by the growth
of the columella and the walls, and showing but few traces of tabulae.
Genera — Seriatopora, Lam. ; Dendrop07-a, Michelin ; Rhabdopora, Edw.
and H.
Fam. IV. Thecid^e. — Corallum massive, with an abundant, compact, spuri-
ous coenenchyma, produced by the septa becoming cemented together
laterally. Tabulas numerous. Genus — Thecia, Edw. and H.

Various additions, modifications, and improvements in the
above classification of the " Tabulata'' were made by Milne-

CLASSIFICA TION. 3

Edwards and Haime during the progress of their classical
monograph on the Fossil Corals of Britain ; many new genera
were added ; and the tribe of the StylophyllincE, to include the
curious Cretaceous genus Stylophyllum, Reuss, was inserted
in the family of the FavositidcE. Most of the changes here
indicated, which it would be needless to point out in detail,
are to be found incorporated in the systematic account of the
" Tabulata" given by Milne-Edwards in his masterly ' Histoire
Naturelle des Coralliaires' (vol. iii., i860).

The first serious attack upon the classification of Milne-Ed-
wards and Haime, and upon the position of the " Tabulata," ys!3.s
made by Professor Louis Agassiz, who in 1857 examined the
living animal of Millepora, and arrived at the conviction that
this genus was truly Hydrozoal (Amer. Journ. Sci. and Arts,
ser. 2, vol. xxvi. p. 140, 1858; Proc. Bost. Soc. Nat. Hist,
vol. vi. p. 373, 1859). This conclusion has since been fully
borne out by the researches of Mr Moseley, to be subse-
quently referred to ; but Professor Agassiz based upon his
discovery a further conclusion which certainly was not war-
ranted by the known facts — namely, that the Hydrozoal nature
of Millcpora sufficiently proved all the so-called '* Tabulate
Corals " to be referable to the Hydrozoa.

Shortly after the publication by Professor Agassiz of his
unexpected discovery as to the Hydrozoal nature oi Millcpora,
Professor Verrill investigated the anatomy of the " Tabulate "
genus Pocillopora, Lam., and showed that the animal of this
Coral was a true Zoantharian, referable to the Aporosa, and
allied to the OcttlinidcE (Review of the Corals and Polypes of
the W. Coast of America, Trans. Conn. Acad., vol. i. pp. 2, 523,
1870; and Affinities of the Tabulate Corals, Proc. Amer.
Assoc, for Adv. of Science, p. 148, 1867). Professor Verrill
likewise, even at this date (Trans. Conn. Acad., loc._ cii.),
powerfully supported the view that the Favositidcs are not
only true Adinozoa, but that they are really referable to the
Zoantharia. In the year 1872 the same high authority pub-
lished an important memoir upon " The Affinities of the Palse-

4 TABULATE CORALS.

ozoic Tabulate Corals with existing Species" (Amer. Journ. Sci.
and Arts, sen 3, vol. iii. p. 187), in which he forcibly pointed out
that the discovery of the Hydrozoal nature oi Miikpora, Lam.,
did not necessarily carry with it the reference of the whole
of the " Tabulata " to the Hydrozoa. On the contrary, he
affirms that, " as to the great majority of the ' Tabulata ' and
' Rugosa,' there can no longer be any reasonable doubt " that
they are essentially animals of the same nature as " the exist-
ing Corals " {i.e., Zoantharid). The family of the Pocilloporidoe
is further established for the reception of Pocillopora and its
allies ; CohimnaiHa is regarded as either a member of the
Ast7'(Eid(E, or as referable to a closely allied family ; and the
FavositidcB are merged with the Poritidce, doubt being ex-
pressed as to whether the group can be retained as even a
sub-family.

In the year 1872, also, was published the admirable " Third
Report on the British Fossil Corals," by Professor Martin
Duncan, which was laid before the British Association for the
Advancement of Science in 1871, and published in the Report
of the Association. In this important memoir Professor
Duncan deals very largely with the structure and affinities of
the " Tabulate Corals" — his wide knowledge of both living and
extinct Actmozoa rendering his views upon this subject par-
ticularly valuable and suggestive. Various of these views will
be noticed subsequently ; and it will be sufficient to state here
that he retains the " Tabulata^' of Edwards and Haime as a
great division of the Zoaiitharia, subdividing it as shown in the
followine table : —

Section Tabulata.
Families.

f Milleporidce. Ccenenchyma cellular.

With ccenenchyma, . . | AcroporidcB. Ccenenchyma compact.

i Fazwsitidce. Walls perforated.

Without ccenenchyma, . . \ LLalysitida;. Walls imperforate.

' AIveolJtid(t. Septa tridentate.

CLASSIFICA TION.

MlLLEPORID^,

acroporid^,
Favositid^,

HALYSITIDiE,

Alveolitid^,
Incertse sedis.

Genera.

Millcpora.-^

Hdiolitcs, Hcliopora, Folytreinacis.

Propora, Flastnopora, Thecia.

Lyellia.

ThecostegUes.
^ Axopora.

Acropora, Scriatopora, Podllopom,
Dendropora, Rhabdopora.
/ Favosites, Koninckia, Favositipora,
\ Michelinia, Rmmeria^ Eminoiisia.
j Syringopora.
' Aiilopora.

Halysites.

Stylophyllum.

C/toiiostegites.

Cohcmnaria.

Beatunontia.

Alveolites.

Ca'iiites.
( Fistulipora.
\ Fletcher ia.

Alcyonaria.

Ch{Etet£s, Monticulipora, Dania, Stellipora, Labcchia.

Another very important memoir upon the " Tabulate Corals "
was published in 1873 by Dr Gustav Lindstrom (Nagra an-
teckningar om Anthozoa Tabulata, Ofversigt af. Kongl.
Vetensk. Akad. Forhandl., 1873. Translated in the Ann. and
Mag. Nat. Hist, sen 4, vol. xviii. p. i, 1876). In this paper
the distinguished Scandinavian palseontologist entirely aban-
dons the ''Tabttlata'' of Edwards and Haime as a distinct
division of the Corals ; Labeckia, E. and H., is placed among
the Hydrozoa, near to Hydractinia ; Monticulipora, D'Orb.,
Fistulipora, M'Coy, and some other forms, are regarded as
Polyzoa ; the Favositidce are placed in the Poritidcu, among the
Perforate Corals ; the Heliolitidce are considered as forming a

Mn a note, Dr Duncan adds that though not satisfied (1872) that Rlillepora is a
Hydrozoon, he has great doubt about its Madreporarian affinities. He also points
to the extremely close relation betv/een Heliolites and Heliopora, since so entirely
confirmed by Mr Moseley.

6 TABULATE CORALS.

special group of uncertain zoological position ; ColiLmnaria,
Goldf., is placed among the Cyathophyllidis, in the section of
the Rtigosa; Flctcheria, E. and H., and Michelinia, De Kon.,
are referred to the CystiphyllidcB ; and Syringopora, Goldf., is
regarded as a Rugose Coral, allied to LitJiostrotioii or DipJiy-
phyllum. I shall have occasion to notice many of the views
expressed by Dr Lindstrom in greater detail in dealing with
the families and genera of the Palaeozoic Tabulate Corals ; and
the general results of his investigations will be best understood
if I append here the following list, in which the various genera
of the " Tabulata^' of Edwards and Haime are referred to what
Dr Lindstrom considers to be their true place in the zoological
system : —

Name of Genus.

To be removed to

Millepora,

Hydrozoa ?

Heliopora,

Alcyonaria (Moseley).

Folytremads,
Heliolitcs, .

Alcyonaria.

Lleliolitidce. (special family).

FistuUpora,

J Some species to Heliolites ; others
1 to the Folyzoa.

Plasviopora,

Heliolitid(B.

Fropora, .

( ILeliolitidce (probably inseparable
\ from Flasmopora).

Lyellia,

HeliolitidcE.

Axopora, .

Hydrozoa ?

Battersbyia.,

Astrceidce (Duncan).

Favosites )
Emmonsia J

{ Sub-family Favositince of the Pori-
\ tidcB.

Michelinia,

CystiphyllidcB.

Alveolites., .

Partly Favositime, partly Folyzoa.

Rcemeria \
Koiiinckla J

Favositiim.

C/icetetes

Montkidipora
Dania

Folyzoa.

Stellipora

Dekayia, .

Folyzoa ?

Beaumoiitia,

Favositime.

Labechia, .

Hydrozoa.

Sfylop/iylltim,

Hydrozoa ?

Halysites, .

Heliolitidce.

SyrmgoponXy

•

j Vicinity of Lithostroiion and Diphy
\ phylluin.

CLASSIFICA riON.

Name of Genus.
Thccosicgites,
Chofwstcgites,
Fletcheria,
Pocillopora,
Cxnites,
Seriatopora,
Thecia,
Columnaria,

In a paper published by IV'

To be removed to
He/iolitidcE.
Michclinia.
Cystiphyllidcc.
Ociili/iidcc (Verrill).
Polyzoa ?
Oculinidce ?
Hcliolitidce ?
Cyathophyllidce.

G. Dollfus in 1875 (Comptes

Rend., t. Ixxx.), the HcliolitidiB are regarded as unquestion-
ably the representatives of the recent MilleporidcB — a view
which Mr Moseley's researches have rendered altogether un-
tenable ; and the PocilloporidcB are regarded, along with the
preceding, as Hydrozoa — an opinion which the researches
of Professor Verrill have sufficiently disproved. Syn'ingopora,
Halysiies, Aulopora, and allied forms, are regarded as being
either Poly son allied to Hippothoa and Idmonea, or else Alcy-
oiiaria. The family of the Chcetetidce is considered as hav-
ing a direct relationship with the Jurassic Polyzoa of the
genus Hetei^opora and the Cretaceous Radiopora. The Favo-
sitidce are regarded as most probably truly referable to the
Polyzoa, the " mural pores " being compared with the inter-
cellular pores of certain EscharcB and Lepralicc, and of some of
the Cyclostomatous Polyzoa {Fwigella and Heteroporclld). It
is clear, however, that the author's conception of the real struc-
ture of the FavositidcB has been grounded upon very imperfect
materials. Lastly, Dendropora and Ti^ackypora — which we
now know to be true members of the FavositidcE — are placed
among the Polyzoa, and are regarded as allied to Horncra.

In 1876 Mr Moseley published his exceedingly important
papers on the anatomy of the recent Millepoi'a and Heliopora
(Notes on Two Species of Millepora, &c., Phil. Trans., 1876;
Structure of a Species of Millepora occurring at Tahiti, Ann.
and Mag. Nat. Hist., 1876; Structure and Relations of the
Alcyonarian Heliopora cserulea, Phil. Trans,, 1876), which at
once threw a flood of light upon the subject of the structure
and affinities of the Palceozoic ''Tabulatay I shall have as'ain

8 TABULATE CORALS.

to refer to the investigations of Mr Moseley, as published in
the above-mentioned and later memoirs ; and I shall merely say
here that their general result was to complete the disintegra-
tion of the "• Tabiilata'' of Edwards and Haime, and to fairly
remove from the Zoautharia certain groups that had previously
been referred to this order of the Actinozoa. Thus, Millepora
and its allies, as formerly asserted by Agassiz, are definitely
proved to be true Hydrozoa, in which class they form, with the
Stylasteridcs, the new order of the Hydrocoi^allincs ; Heliolitcs
and its numerous allies, instead of being relations of Millepora,
are shown conclusively to be Actinozoa, but to be at the same
time referable to an unsuspected order of this class — namely, to
the Alcyonaria ; while various familiar types of the Palaeozoic
'"Tadtilala" are brought by these discoveries into more or less
probable relationships with either the Hydrozoa or the Alcyo-
naria; and light of the most important character is afforded as
to certain structural features in the Palaeozoic types, which
have hitherto proved obscure or inexplicable.

In the article "Corals" in the ' Encyclopsedia Britannica '
(9th ed., vol. vi., 1877), I gave a short account of the then
existinof state of our knowledo-e as to the structure and affin-
ities of the "Tabulate" Corals. In this article the researches
of Moseley are accepted ; the Favositidce are referred with
some doubt to the Perforate Zoantharia ; the Chcstetidce are
separated from the FavositidcSy and regarded as possibly Alcyo-
narian; the Syringoporidce are shown to have affinities with
the FavositidcB ; and the conclusion is arrived at, that if any
forms can be retained as a " Tabulate " order of the Zoantharia,
it is probably those represented by Syringopora and Halysites,
with their allies.

Lastly, Professor Zittel (Handbuch der Paleeontologie, Bd.
i. Lief, ii., 1879) accepts in the fullest sense the abolition of
the "Tabulata" of Milne-Edwards and Haime, and disposes
of the members of this group in different directions. Millepora
and its allies are placed, as is proper, in the Hydrozoa — as also,
with less reason, is LabccJiia; the family of the Favositidce is

CLASSIFICA TION. 9

referred, as is also probably correct, to the Perforate Corals,
and is regarded as a sub-family of the Poritida^, Koninckia
being removed from it, and placed with Alveopora in another
sub-family (the Alvcoporimr) of the same group ; Syringopora,
Aulopoi'a, Halysites, and their allies, are placed (without suffi-
cient reasons adduced) among the Alcyonaria, in the family of
the TiibiporidcB ; and the ChcBtetidce are entirely excluded from
the Actinozoa, being presumably regarded as truly belonging
to the Polyzoa.

The preceding historical sketch is necessarily extremely
brief and imperfect, the limited space at my disposal not allow-
inor it to be otherwise ; but it will be sufficient to show the
principal tendencies of the more recent researches of naturalists
and palaeontologists with regard to the old group of the " Tab-
ulate Corals." These researches, though still incomplete, are
so far advanced that the abandonment of the ''Tabulata'' as a
distinct group of the Zoantharia can hardly be avoided ; while
the removal elsewhere of some of the principal forms previously
included under this head is already a fact accomplished. It is,
indeed, now quite clear that the chief character relied upon by
Milne-Edwards and Haime, in their definition of the ''Tabu-
lata'' — namely, the presence of "tabulae" — is one of very
limited classificatory value. Thus, tabulae occur in Pocillo-
i)ora, Cyathophora, Cwlasircea, Claiisastrcea, and occasionally
in Lophohclia, among the Zoantharia Aporosa ; in Alveopora,
and the allied Favositipora, among the recent Zoantharia Per-
forata ; in Heliopora and its allies, in the Alcyonaria, as well
as occasionally in Tubipor-a ; in the great majority of the
Rugose Corals ; in Millepora and its allies among the Hydro-
zoa; and lastly, in a few extinct types of the Polyzoa {e.g.,
Radiopora and Heter^odictya). The mere fact of the occurrence
of tabulae in so many forms of such diverse zoological affinities,
is sufficient proof that these structures cannot be used in form-
ing a classification of the Corals; but it is at the same time con-
clusive that the "tabulae" of these different types, though undis-
tinguishable in appearance and performing identical functions,

lo TABULATE CORALS.

cannot be precisely and in all cases homologous structures.
With regard to the " tabulae " in the true Adinozoa, Professor
Verrill concludes that " they are formed after each discharge of
ova : the vacuity thus produced, being useless, is cut off from
the visceral cavity above it by the formation of a septum.
Therefore, if the eggs be discharged from all the radiating
chambers simultaneously, or if from any other cause the polyp
abandons all the chambers simultaneously, it is obvious that a
complete septum or transverse plate will be formed across the
entire tube ; but if the eggs be discharged at different times
from the ovaries occupying the various radiating chambers, the
septa formed below them in the different chambers will not be
coincident, or exactly at the same level in all. It would seem,
therefore, that the existence or non-existence of complete trans-
verse plates is simply a matter of periodicity in the discharge
of ova" (Amer. Journ. Sci. and Arts, ser. 3, vol. iii. p. 187).
Dr Lindstrom has further adduced a considerable body of evi-
dence in support of the view that the " tabulae " are only a
modification of the endothecal "dissepiments" (Ann. and Mag.
Nat. Hist, ser. 4, vol. xviii. pp. 2, 3). That this is the case in
certain instances (such as Ccelastrcsa, Verrill) seems quite un-
questionable; and it is indeed easy to see how the simultaneous
production of dissepiments in all the intermesenteric chambers,
at one level, would give rise to a structure entirely undistin-
guishable from a " tabula." There are, however, some consid-
erations which should not be lost sight of, before it is concluded
that the " tabulae " of the tabulate Actmozoa are merely modified
interseptal dissepiments. Thus it is to be remembered that in
the Rugose Corals there is generally a simultaneous develop-
ment of both these structures, and that the "tabulae" are best
developed in the axial region of the visceral chamber, into
which the septa either only penetrate slightly {Dip/iyp/iylluin)
or do not enter at all {Amplexus), and in which, therefore,
"dissepiments" are either scanty or totally absent. Again, in
various members of the Favositidcs, the septa are obsolete ; and
there are therefore necessarily no " interseptal dissepiments,"

CLASSIFICA TION. 1 1

in the ordinary acceptation of this term, though the " tabulae "
are well developed. Moreover, it begs the question at issue to
speak of the vesicular plates of the Cystiphyllidce as being of the
nature of " crowded and regular horizontal dissepiments I' which
simulate "tabulae;" since it is just as likely that they are
crowded and anastomosing tabulce, which simulate *' dissepi-
ments." In the entire family of the Chcctetidce (assuming these
in the meanwhile to be Actinozod) the " tabulae " are well de-
veloped; but there are no septa, and therefore no "dissepi-
ments," unless the latter are represented by the tabulae.
Lastly, in the Helioporidce it has been shown by Mr Moseley
that the so-called septa are not homologous with the septa of
the Zoantharia ; and it is therefore improbable that the well-
developed tabulae of the former should be homologous with
the " interseptal dissepiments " of the latter.

Whatever may be, however, the nature of the " tabulae "
in the various groups of Actinoza which possess them, and
whether or not they are always periodic partitions formed
after the discharge of the ova (Verrill), or mere modifications
of the interseptal dissepiments (Lindstrom), it is clear that
they cannot be homologous with the apparently identical struc-
tures in certain other sections of the old group of the " Tabu-
lata." Mr Moseley, for example, has shown that the Milleporce
are truly Hydrozoa, and that their ova are therefore not pro-
duced within the visceral chambers. It is clear, therefore, that
in these forms the " tabulae " cannot be modified " dissepi-
ments," and still less partitions formed subsequent to the
extrusion of the ova. It must also be admitted that any
transverse plates which may be found to intersect the cells of
undoubted Polyzoa (such as Heterodictya, Nich.) must be of a
fundamentally different nature to the " tabulae " of either the
"tabulate" Actinozoa or of the Millepores, though they may
not be distinguishable from these in appearance.^

1 It follows from the above that if the name of " tabulse" be retained for the
transverse partitions found in the visceral chamber of certain Actinozoa, it can
hardly be said in any strict scientific sense that "tabulje" are present in certain
Hydrozoa {^Milleporida) and certain Polyzoa {Hetcrodictya). The proper course,

12 TABULATE CORALS.

With the abandonment of the "tabulae" as structures of
classificatory significance, the '"Tadiilata" of Milne- Edwards
and Haime must necessarily be broken up and undergo
redistribution. It remains, however, for consideration, what
groups are really included under the old name of ''Zoantkaria
Tabulatal' and whether or not this name may still be retained,
in a restricted sense, for any of the forms originally placed
under it. By the investigations of Agassiz, Verrill, Lindstrom,
Duncan, Moseley, Rominger, and others, we have been made
acquainted with the true structure and relationships of several
of the groups which constituted the old division of the Tabu-
lata, and my own researches upon the varied and numerous
Palaeozoic types have enabled me to throw some light upon
the nature and position of some of the others. Our present
knowledge is admittedly imperfect ; but it would appear that
the division of the Zoantharia Tabtdata, as until very recently
understood, comprises about twelve distinct groups of animals.
Of these groups, the first two are not known (with any cer-
tainty, at any rate) to have had any Palaeozoic representatives,
and I shall therefore say here what appears to me to be
necessary concerning them ; while I shall merely summarise
the characters of the remaining groups, all of which I shall
have to treat of hereafter at greater length : —

I. MiLLEPORiD/E. — The corallum in this group is usually
foliaceous, lobate, or sub-massive, and it is composed of an
extremely porous coenenchyma, traversed in every direction
by tubular canals, which freely communicate with one another,
and which also open into the visceral chambers of the polypites
themselves. The surface (fig. i, c) exhibits two sets of aper-
tures, one large and the other small, the larger ones being
much the fewest. The large openings (the true " calices ")
are the mouths of tubes which are crossed by well-developed
transverse partitions or "tabulae" (fig. i, b), the living animal
inhabiting only the outermost of the chambers thus formed.

in fact, would be to give another name to the structures in the two latter groups
which simulate the "tabular" oi' the first group.

CLASSIFJCA TION.

13

The smaller tubes are similarly "tabulate." No "septa" are
present. The living- animal of Millepora was first examined
by Professor Louis Agassiz, as the result of which he pro-
nounced it to be a Hydrozoon, allied to Hydradinia ; but its
anatomy was first thoroughly studied and worked out by Mr
Moseley (Phil, Trans,, vol. clxvii. p. 117, 1877), who showed
that it was in reality the type of a special group of Hydrozoa,

Fig. I. — A, Portion of a mass of Millepora alc/coniis, of the natural size; B, Portion of the
same, cut open vertically to show the larger tabulate tubes (/, /), and the spongy coeno-
sarcal skeleton (c, c), enlarged; C, Small portion of the surface, enlarged to show the
larger and smaller openings (/', (f) inhabited by the different zooids, and the reticulated
calcareous tissue of the skeleton ; D, Part of a polypite, enlarged, showing two whorls of
knobbed tentacles. (A, B, and C are after Milne-Edwards and Haime ; D is afier
Martin Duncan and Major-General Nelson.)

to which he gave the name of HydrocorallincE. According to
the observations of this naturalist, the colony of Mtllcpora con-
sists of two kinds of zooids, differing from one another in size,
in structure, and in function. The larger zooids — the "gastro-
zooids " of Mr Moseley — occupy the larger tubes of the coral-
lum, and have the form of short polypites, each of which pos-
sesses four tentacles, surrounding a central mouth, which opens
into the gastric cavity of the zooid (fig, 2, a). Mixed with the
"gastrozooids," or surrounding these in definite systems, are
more numerous long and slender zooids — the " dactylozooids "
of Mr Moseley — which carry numerous clavate tentacles (fig, 2,

14

TABULATE CORALS.

b), and are destitute of any mouth. The " dactylozooids " per-
form the functions of prehension for the colony, and supply
food to the " gastrozooids," by which the work of digestion

Fir

. 2. — Enlarged view of a portion of the surface of a living colony of ]\Iilh'po)-n nodosa,
showing the expanded zooids of a single system, a, Central "gastrozooid ;" /', One of
the mouthless "dactylozooids." (After Moseley.)

and assimilation is carried on. The nutritive fluid thus elabor-
ated Is distributed over the entire colony by means of branched
coenosarcal canals, which communicate with the body-cavities
of the zooids, and ramify in every direction through the spongy
ccenenchyma.

Of the genera associated by Edwards and Halme with
Millepora, Heliopora and its Palaeozoic and Secondary allies
are now known to be referable to the Alcyonaria; Fistiilipora,
M'Coy, belongs undoubtedly to the family of the Monticulipor-
idce ; and the Tertiary Axopora, with its fasciculate columella,
is of uncertain affinities. Millepora itself Is only known as a
Tertiary fossil, and as living ; but the Cretaceous genus Poro-
sphcEra, Steinm., appears to be closely related to Millepora,
and therefore also to belong to the HydrocorallincE.

II. PociLLOPORiD^. — The corallum (fig. 3) of Pocillopora,
the type of this group. Is dendroid or foliaceous, composed of
numerous tubular corallites, which are surrounded by an imper-

CLASS I PICA TION.

15

forate compact coenenchyma ; are provided with six, twelve, or
twenty-four septa, sometimes obsolete ; and are intersected by
complete transverse tabulae. A rudimentary columella is pres-
ent. The animal of Pocillopora has been examined by Profes-
sor Verrill {loc. jam cit.), who describes the polypes as being
" exsert in expansion, with a regular circle of twelve nearly
equal, stout, tapering tentacles surrounding the circular disc ;
and twelve internal, radiating, fleshy lamellee show through
the disc. Thus they closely resemble the polypes of Stylo-
pJiora, Porites, and Madrepora, which are among the most
typical of the true polypes. The existence of stellate cells

Fig. 3. — A, Portion of the corallum of Pocillopora aspera, var. lafa, Verrill, of the natural
size ; B, Part of the surface of same enlarged ; c. Section of the corallites of the same,
showing the columella, enlarged ; D, Vertical section of the same, enlarged, showing
tabulce. (After Dana.) Recent.

with six or even twelve well -developed radiating septa in
several species of Pocillopora {e.g., P. eloiigata, Dana, P.
plicata, D., P. stellala, V.), should be sufficient evidence that
such Corals have no Acalephian affinities whatever, even
without the conclusive evidence derived from a study of the
living polypes " (Amer. Journ. Sci. and Arts, ser. 3, vol. iii.
p. 191).

It cannot be doubted, then, that Pocillopora, Lam., is a true
Aporose Zoantharian, most nearly allied to the OcttlinidcE ; but
there is some doubt as to the forms which should be associated
with it, since in none of the allied types are we acquainted with
the structure of the animal itself The corallum of Seriatopora,
Lam., however, so closely resembles that of Pocillopora in its

i6

TABULATE CORALS.

general structure, that this genus must ahnost certainly be
placed alongside of the latter, even if not actually united with
it, as proposed by Professor Martin Duncan. We may thus
abolish the family SeriatoporidcB, of which Seriatopoi^a was the
type. The genus Pocillopora is Recent and Kainozoic, and it
is questionable if any fossil forms of Sci'iatopora are known.
It may at any rate be taken as certain that the alleged forms
of Seriatopora from the Palaeozoic deposits will be proved to
have different affinities. The Palaeozoic genera Trackypora,
Deiidropora, and Rhabdopora, usually associated with Seria-
topora, Lam., are, again, truly Perforate Corals destitute of a
coenenchyma, and belonging to the FavositidcE.

III. Favositid/E. — The corallum in this family is of very
variable form, but is composed of polygonal or subcylindrical
corallites, which are usually in close contact throughout their
entire extent, and are furnished with well -developed walls.
The walls are, however, perforated by a greater or smaller
number of rounded apertures — the " mural pores " (fig. 4, b)
— by which the visceral chambers of contiguous polypes are
placed in direct communication. There is no true coenen-
chyma ; and the condition of the septa is extremely variable,

Fig. 4. — A, Portion of the corallum o{ Favosites favosa, of tlie natural size ; B, Portion of four
corallites oi Fa7'osifes Gothlandica, enlart^ed, showing the talnilx* and the "mural pores."

these structures being sometimes obsolete (some forms of
Trackypora^ &c.), sometimes in the form of marginal lamellae
or ridges {IVyciopora, Nich.), and most commonly represented
by vertically-disposed rows of spinules (most species of Favo-

CLASSII^ICATION. 17

sites). The tabulae are usually well developed and complete,
but they are sometimes imperfect {Favositcs hemispherica, Yand.
and Shum.)

After an extended study of the minute structure of the
FavositidcE, I cannot doubt but that Professor Verrill and
Dr Lindstrom are right in referring all the Corals usually
included under this head to the Zoantharia Pei^foj^ata. I
also fully recognise the many points of resemblance between
the FavositidcB and the PoritidcB, but I am not prepared to
follow the above-mentioned distingfuished authorities in reofard-
ing the present group as a mere sub-family of the Poritid<2.
On the contrary, I think that the group Favositidcs, as here
understood, embraces a large number of types (mostly Palaeo-
zoic), all of which are more or less allied to the PoritidcE, and
some of which may perhaps be capable of final removal to the
latter family, but which really represent a series of separate
though allied groups. The reasons for this opinion will be
stated at greater length hereafter. I need only say here
that there is not the slightest ground, in my opinion, for
regarding the Favositidcs as anything but true Actinosoa, or
for removing them from the order of the Zoantharia. They
are not connected with the Heliolitidcs by any links sufficiently
close to lead us to suppose that they are Alcyonaria ; and the
hypothesis of Dollfus (Comptes Rend,, t. Ixxx., 1875), that
they are truly referable to the Polyzoa, hardly requires serious
refutation.

IV. CoLUMNARiAD/E. — Under this head I provisionally place
a few Palaeozoic Corals, of which the only typical and un-
doubted examples known to me are C. alveolata, Goldf.
{Favistella stellata, Hall), and C. caticina, Nich. Both of these
have coralla composed of polygonal or subcylindrical corallites,
with well-developed compact walls, not penetrated by " mural
pores." The septa are lamellar, in two series, those of the
longer set extending nearly or quite to the axis of the visceral
chamber. There is no columella ; and though the corallites
may be to some extent disjunct, there is nothing of the nature,

B

i8

TABULATE CORALS.

of a coenenchyma. The tabulse are always remarkably well
developed. Columnaria f Halli, mUii (the C. aheolata of
American palaeontologists), may be temporarily included in this
group, though there are grounds for believing that the walls of
its corallites are perforated, and its septa are of the marginal
character oi Nydopora Billingsii, Nich., which has unquestion-
able " mural pores," and must therefore be placed among the
Favositidcs. We may also provisionally place in or near the
ColumnariadcB the singular genus Lyopora, Nich. and Eth. jun.,
though it differs from the typical ColumnaricB in the great thick-
ness of its walls and the very rudimentary condition of its septa.

As to the precise position of the typical ColumnaricB in the
zoological series, it does not seem at present possible to speak
with anything like certainty. The typical forms of the group
exhibit certain curiously Rugose features in the disposition of
the septa, and may really form a special type of the Rngosa.
On the other hand, they present some conspicuous points of
resemblance to the AstrcBidce among the Zoantharia Aporosa.

V. Syringoporid^. — In this group the corallum is fascicu-
late (figs. 5-7), commencing in the form of a creeping stolon-
iferous network, which sends up vertical and more or less
cylindrical corallites, which are never in absolute contact, ex-

Fig. 5- — Syritigopora reti-
forviis. Silurian.

Fig. 6. — Syriiigopora vcr-
ticillata. Silurian.

Fig. 7. — Syringopora Dal-
immi. Silurian.

cept, perhaps, at quite limited intervals, and are enclosed by
strong compact walls. The visceral chambers of contiguous
corallites are placed in direct communication by means of
hollow connecting-processes. Septa, of a spiniform and rudi-
mentary character, are present as a rule. The tabulae are
well developed, more or less funnel-shaped, and sometimes

CLASSIFICA TION. 1 9

eivinof rise to an axial tube in the median line of the visceral
cavity. There Is no columella. The entire group, so far as
known, is confined to the Palaeozoic period.

It is probably impossible, with our present knowledge, to
assign an absolutely final place to the Syringoporidce in the
zoological series. I am quite unable to agree with the opinion
held by Dana, Hseckel, and Zittel, that the true place of Sy-
ringopoi^a and its allies is in the immediate neighbourhood of
the recent Ttcbipora ; as I can see nothing but resemblances of
an analogical nature between these two genera. Nor can I
accept the view advocated by Lindstrom (Ann. and Mag. Nat.
Hist, ser. 4, vol. xviii. p. 14), that Syringopora is truly a Rugose
Coral, with relationships to LitJwstrotiou and Diphyphylhim.
Nor, again, am I at present inclined to admit that the Corals
usually grouped together under the generic titles of Aulopora
and CladocJionus ( = Pyrgia, E. and H.) are really nothing more
than young forms of Syringopora ; though I fully grant that the
immature stages of the latter may be undistinguishable from
the fully-grown condition of the former. On the contrary, I
am upon the whole disposed to think that the real relation-
ships of the Syringoporidce are with the FavositidiE, and that
they should therefore find a place, though a special one, in
the series of the Zoantharia Perforata. I regard the con-
necting-tubes (when present, as apparently they are not inva-
riably) as being the homologues of the " mural pores " of
the FavositidcE; and the curious genus Syringolitcs, Hinde,
which I shall subsequently describe, affords an unquestion-
able link between these two groups. This singular type, in
fact, possesses the infundibuliform tabulae, and even the axial
tube, of certain Syringoporid(s, along with the polygonal,
contiguous corallites, and the serially-disposed " mural pores,"
of the Favositidcs. The septa of Syi^mgopora are furthermore
of the spiniform and rudimentary character so distinctive of
the FavositidcE I and there is no solid reason, so far as I am
aware, for regarding them as being really of the nature, of the
"pseudo-septa" of certain Alcyonarians.

2 0 TABULATE CORALS.

VI. AuLOPORiD/E. — This group is at present in such a totally
chaotic condition, that it is almost impossible to come to any
positive conclusion as to its true relationships or as to the
forms which it may contain. The genera Aulopora and
Cladochomis { = Pyrgia) were, as is well known, raised by
Milne-Edwards and Haime to the rank of a distinct sub-order
of the Zoantharia — the Z. Tiibidosa (Pol. Foss. des Terr. Pal,
310, 185 1 ) — having been previously placed by them in the Al-
cyonaria. The alleged characters of the family are, that the
pyriform corallites are destitute of "tabulae," and possess nothing
but vertical striae representing the septa, while there are no
mural pores or connecting-tubes by which the visceral chambers
of contiguous corallites are placed in direct communication.
Taking Azdopora itself (fig. 8, a) as the type of this group, the
corallum is creeping, and attached by the whole of its lower

Fig. 8. — A, Portion of the corallum of Aulopora tuhafo run's, Goldf., from the Devonian of
the Eifel, of the natural size ; B, Two corallites of the same enlarged, showing septal
striK ; c, Cladochomis {Pyrgia) Michelini, E. and H. , Carboniferous, of the natural size ;
D, The same slightly enlarged, showing the interior of the calice.

surface to some foreign body. The basal stolons divide and
send up the tubular or trumpet-shaped corallites, the terminal
portions of which are free and erect ; but in no case is the pro-
cess carried to the extent of producing a fasciculate corallum.
The tubes are for the most part not in contact with one

CLA SSIFICA TION. 2 1

another, and there is no evidence of the existence of " mural
pores" in such parts of their extent as they may be actually
contiguous. The septa are reduced to marginal striae ; and
horizontal complete tabulae are known to be present in certain
forms, though they have not yet been detected in others.

It is well known that the basal and young portion of the
corallum of Syringopora is in the form of a creeping stolonifer-
ous expansion, almost undistinguishable from the adult colony
oi Aulopora in appearance. This fact has led high authorities to
the belief that the genus Aulopora has no existence, and that
it is merely based upon young aoXom^s oi Syi^ingopora. This
view of the subject appears to me to be untenable — with our
present knowledge — and I think Aulopora to be really quite
distinct from Syringopora. I base this belief upon the fact
that the corallum in Aulopora is always prostrate and parasitic,
never becoming erect ; that there are no traces of hollow con-
necting-processes between the corallites ; and that the tabulae
(when known to be present) are horizontal, or if infundibuli-
form, do not give rise to an axial tube. There is also the
strong geological argument for the distinctness of the genus,
that formations abounding in Syringoporce (such as the Car-
boniferous Limestone series of Britain) are almost (in most
places wholly) destitute oi Atiloporcs ; whereas the latter are
extremely plentiful in deposits (such as the Devonian Limestone
of Gerolstein in the Eifel) in which Syringoporcs are almost
or quite unknown. The genus CladockonnSy M'Coy (which
is apparently the same as Pyi'gia, Edw. and H.), seems to
comprise forms of different affinities. Some of the species
seem to be tabulate, with horizontal tabulae, and may perhaps
be identical with Aulopora proper. The Cladochomis crassus
of M'Coy, however, has an entirely peculiar internal structure,
which must remove it altogether from the Auloporidce.

Vn. Halysitid/E. — In this group, typified by the common
" Chain-corals," the corallum is composed of long cylindrical
corallites, united with one another successively on opposite
sides of the tubes, so as to give rise to flattened laminar expan-

2 2 TABULATE CORALS.

sions, each composed of a single layer of corallites, these layers
frequently anastomosing and uniting with one another (fig. 9,
a and b). Between each pair of corallites, and forming the
medium of junction between their opposed faces, is generally
a much smaller tabulate tube, with close-set tabulee (fig. 9, d).

Fig. 9. — a, Haly sites catomlaria, Linn., small variety, of the natural size; b, Large variety of
the same, of the natural size ; c, Halysites agglomeraia, Hall; d, Section of two corallites
of the same, enlarged. Niagara Limestone.

The larger tubes are crossed by complete, generally horizontal
tabulae, which are much farther apart than those in the smaller
intermediate tubes. The septa are minute and spiniform, and
the walls of the corallites are entirely compact and imperforate,
nor are there any connecting - tubes by which the visceral
chambers of different polypes are placed in communication.

By Milne-Edwards and Haime the family of the Halysitidce
was made to include the SyringoporcB ; and that there are cer-
tain alliances between these groups cannot be denied. I con-
sider, however, that the fact that the polypes of Halysites are
destitute of any communication with their neighbours is suffi-
cient of itself to warrant the separation of the genus from the
SyringoporidcB, The latter, as has been seen, may perhaps
be regarded as aberrant Perforate Corals ; but it is difficult to
speak at all positively as to the systematic position and affin-

CLASSIFICA TION.

23

ities of the Halysitidce, as here restricted. Upon the whole,
I am inchned to think that Halysites will find its nearest ally
in the HelioporidcB, which it resembles in one important fact
— namely, in the general possession of two sets of tubes (indi-
cating the existence of two sets of zooids). Moreover, the tubes
of the one series are of large size, with remote tabulae ; while
those of the other set are small, and have close-set or vesicular
tabulae. If this conjecture be correct, then Halysites must be
removed from the Zoaiitharia to the Alcyojiaria (a course
which several authorities have already followed) ; but it will in
any case form the type of a distinct group.

Fii^. 10. — A, Fragment of the corallum of 7\iraditnji miiitts, Safford, from tlie Lower Silu-
rian of North America, of the natural size ; B, Transverse section of the same, enlarged
ten times, showing the petaloid form of the tubes and the short septa; c, Vertical section
of the same similarly enlarged, showing the tabuloe.

VIII. TETRADiiDiE. — This group includes only the singular
Silurian genus Tetradium, Dana, in which the corallum is
massive, and is composed of polygonal or subcylindrical coral-
lites of great length, and closely contiguous. No " mural
pores " or other openings in the walls are present. The
tabulae are numerous and complete, and the septa are few in
number, typically four, short, and seeming as if formed by
inflections of the wall (fig. 10). Most of the examples of
Tetradium have the form and general appearance of ChcBtetes
radians, Fischer, and its allies ; but Safford (Amer. Journ.
Sci. and Arts, ser. 2, vol. xxii. p. 236, 1856) records the
occurrence of specimens in which the corallites are united in

24 TABULATE CORALS.

single intersecting series, as in Halysites, and Billings has
figured similar forms (Geol. of Canada, fig. 71, b). Professor
Safford regarded the genus as referable to the Rngosa, on
account of the quadripartite character of the septa ; but the
relations of the genus to Haly sites were pointed out by Mr
R. Etheridge, jun., and myself (Ann. Nat. Hist., sen 4,
vol. XX. p. 163). It approaches Halysites in its long tubular
corallites, its imperforate walls, and occasionally in its mode
of growth ; but its peculiar septa, and the want of smaller tubes
among the larger ones, would show it to be the type of a
special group. Its septa are much more like those oi Hdiolites
than of Halysites, looking as if they were formed by inflections
of the wall inwards along its whole length; and I think that the
genus will probably have to be referred to the Alcyonaria,
though I know of no group of this order to which it could be
definitely referred.

IX. Thecid^. — This group comprises only the singular
Silurian genus T/iecia, Edw. and H., the corallum of which
forms laminar expansions, covered below by an epitheca, and
having the calices placed upon the upper surface. The
tubular corallites cannot be said to be bounded by distinct
proper walls ; but they are embedded in and surrounded by
a dense tissue composed of minute polygonal vertical tubuli,
which normally open on the surface by very small and irreg-
ular, often stelliform, apertures. A few blunt septal ridges
(five to ten in number) project into the visceral chambers of
the polypes, which are crossed by irregular but well-developed
tabulse, and likewise often communicate with neiehbourino-
tubes by means of canals passing horizontally through the
intervening tissue. The smaller tubuli, which separate the
larger corallites, do not appear to be distinctly tabulate.

The structure of this genus is so extraordinary that it must
clearly form the type of a special group, as it was made to do
by Milne-Edwards and Haime. Nor need we wonder that its
anatomy has been so little comprehended, seeing that its real
structure can only be made out by means of microscopic sec-

CLASSIFICA TION. 2 5

tions, and that, owing to the great density of its tissues, even
the finest of these leave certain important points obscure. I
shall have to deal with the orenus at greater length at a later
period, and will only say here that it seems to form in some
respects a link between the Perforate Corals and the Alcyo-
narian family of the HelioporidcE. It resembles the former in
the fact that the visceral chambers of contienous corallites are
placed in communication by a well-developed system of hori-
zontal canals ; and, on the other hand, it approaches the latter
in the fact that the ordinary polypes are surrounded by what has
been generally regarded as a tubular " coenenchyma," though
not truly of this nature. The so-called " ccenenchymal tubuli "
— judging from the analogy of the recent Hcliopora — are really
tenanted by special zooids, and are therefore not truly ccenen-
chymal. In the possession, then, of a series of large polypes
surrounded by a much more numerous series of smaller special-
ised polypes, Thccia agrees with Heliopora and Heliolites; and
the genus is therefore probably Alcyonarian. It differs, how-
ever, from the above in the fact that the corallites do not possess
distinct walls ; the septa of the large tubes are broad and tooth-
like, and the interstitial tubuli are apparently destitute of
tabulae, irregular, and opening on the surface by very minute,
often stellate, apertures ; while the larger polypes are directly
connected by lateral canals. These peculiarities fully entitle it
to be regarded as the type of a special family.

X. Helioporid/E. — This family has been founded by Mr
Moseley (Phil. Trans., vol. clxvi. p. 92, 1876) for the recep-
tion of the extraordinary recent Hcliopora, and the long ex-
tinct Heliolites, Plasmopora, and allied forms. The corallum
in this family (fig. 11) is composed of two sets of corallites, a
larger and smaller — the latter hitherto, but wrongly, termed
" ccenenchymal tubuli." The larger tubes are furnished with
delicate septa (generally twelve in number), and are traversed
by remote complete tabulae (fig. 11, c). The smaller tubes
everywhere surround the larger ones, have no septa, and are
crossed by more numerous tabulae. Heliolites and most of its

26

TABULATE CORALS.

allies are Palaeozoic, Polytremacis is Secondary, while Helio-
pora commences in the Chalk and still survives. The true
affinities of this singular group of Corals were quite unknown

Y\g. II.— A, Small colony oi IlelioUtes vicgasfovta, of the natural size ; B, Small portion of the
surface of the same, magnified, showing the calices of the large and small tubes [a and b);
c. Vertical section of the same, enlarged, showing the large tabulate corallites [a) and
the smaller tabulate tubes of the so-called cojnenchyma (/').

till Mr Moseley examined the living animal of Heliopora
ccsrulea, from which he was enabled to prove conclusively
that Heliopo7'a and its ancient relatives are truly Alcyonaria,
and not Zoantharia. The corallum in Heliopoj^a ccerttlca is
in all essential features entirely similar to that of Heliolites.
As in the latter genus, the corallites are tubular, with well-
developed tabulae, and having their walls folded in such a
manner as to give rise to a variable number (generally twelve)
of septal laminae. The coenenchyma, so called, is composed
of slender tubes, of smaller size than the true corallites, packed
closely side by side, crossed, like the corallites, by regular
transverse tabulae, but destitute of septa. The soft parts
occupy only the parts of the corallum above the uppermost
tabulae, and therefore only a surface - layer of the colony is
actually alive. The polypes are completely retractile, with
eight pinnately-fringed tentacles and eight mesenteries. The
mesenteries, however, have no correspondence with the septa,

CLASSIFICATION. 27

which are twelve in number as a rule. The septa are thus
seen to be pseudo-septa, and they cannot be regarded as being
homologous with the septa of the Zoantharia sclerodermata.
The so-called coenenchymal tubes are occupied by sacs lined
by the endoderm, which are closed externally, but communi-
cate freely with the body-cavities of the polypes by means
of transverse canals ; and Mr Moseley suggests, with great
probability, that these are really of the nature of rudimentary
sexless polypes.

XI. CHiETETiD.E. — This group is almost certainly made up
of very heterogeneous materials, and will undergo disintegra-
tion when subjected to a sufficiently searching investigation.
As it is even, the lines along which this disintegration will take
place can be to some extent discerned. Taking the miscella-
neous assemblage of forms at present included in it, no other
general definition of the group seems possible than that it com-
prises very variably -formed corals, composed of contiguous,
thin-walled, mostly prismatic corallites, which have imperfor-
ate walls, are intersected by well-developed tabulae, and are
destitute of septal laminae or spines.

Taking the typical members of the Chcstetidce — viz., Chcstetes
radians, Fischer, and its few immediate allies — we find that we
have to deal with corals in most essential respects similar to
those of the typical Favositidce, except that " mural pores " or
other openings in the walls are wanting, while there are (in
reality) no traces of septa, and the walls of the corallites are
completely amalgamated. These differences are of course such
as to show that the place of Chcetetes in the system must be far
removed from that of Favositcs. I am nevertheless satisfied
that ChcEtctes radians, Fischer, and the forms immediately
related to it, are genuine Actinozoa, though I am not able to
assign to them any certain place in this class. So far as one
can judge, they seem to have more affinities with the Alcyo-
7iaria than with any other group.

The position of the numerous forms referred to Monticuli-
pora, Fishdipora, and other allied types (which I shall provi-

28

TABULATE CORALS.

sionally regard as a separate group, the MontictUipoindcs) is,
again, uncertain. Strong evidence has been brought forward to
prove that all these forms are Polyzoa ; but it certainly cannot
be said that this conjecture has yet been sufficiently established.
I shall consider this subject again at greater length ; and I need
only add here, that though some of these forms may possibly
turn out to be Polyzoa, I am strongly disposed to think that the
majority will prove to be true Actinozoa. This seems to be
indicated, as a general conclusion, by their close resemblance in
many cases to types of an undoubted Coelenterate nature ; by
the fact that their coralla are usually or always composed of
two sets of corallites, pointing to a heteromorphic condition of
their zooids, such as is highly characteristic of many of the
Ccelenlerala, and especially of certain of the Alcyonaria ; and
lastly, by the fact that no forms possessing their characteristic
features m conjiuidion have as yet been pointed out as existing
among either recent or fossil Polyzoa.

XII. Labechid^. — This extraordinary group comprises
only the anomalous genus Labcchia, E. and H., at present
only known as a Silurian fossil. The skeleton in this genus
forms a laminar or expanded mass (fig. 1 2), the under sur-

Fig. 12. — A, A small specimen of Labechia confei'ta, E. and H., from the Upper Silurian of
Gotland, of the natural size. B, Portion of the upper surface of the same, enlar<;ed. c,
Part of a vertical section of the same, enlarged : a, the calcareous columns, represented
as opaque ; b, the lenticular vesicles filled with calcite.

face of which is covered by an epitheca, while the upper ex-
panse shows an apparently imperforate surface, rising above

CLASSIFICATION. 29

which are close -set tubercles. Microscopic sections show
that these tubercles are the projecting summits of a series
of short, calcareous, and entirely solid, though seemingly
primitively tubular, columns, separated from one another by a
loose vesicular tissue, formed by the anastomosis of curved
calcareous lamellae. Dr Lindstrom has strongly supported the
view that Labcchia — originally placed by Edwards and Haime
among the ChcstetidcB — is truly a Hydrozoon, allied to Hydrac-
tinia. The peculiarities in its structure are, however, so
numerous, and the apparent total absence of any superficial
openings of any kind is so puzzling, that I do not at present
see how it can be placed among either the Hydrozoa or the
Actinozoa ; nor am I able to give any definite opinion as to
its affinities beyond the negative one, that it certainly has no
relationships with the ChcctetidcB proper; while such resem-
blances as it shows to certain of the Monticulipo7'-idcB are
largely counterbalanced by special and apparently inexplicable
peculiarities of its own.

3°

CHAPTER II.

THE FAVOSITID^.

The principal characters of this family have been already
given, and merely need brief recapitulation here. The coral-
lum — whatever its form may be — is usually composed of more
or less prismatic corallites, which are generally in complete
contact throughout, and have well-developed walls, which are
perforated by a greater or less number of " mural pores," or
apertures, by which the visceral cavities of contiguous pol-
ypes are placed in direct communication. There is no true
ccenenchyma, and the condition of the septa is extremely
variable, while tabulce are usually numerous and complete.

As regards the above characters, the general form of the
corallum is for the most part either massive or dendroid ; but it
is sometimes lamellar or frondescent (some types of Pachypora
and Ccenites) ; and Ronmigeria, Nich,, affords an example of a
subfasciculate corallum, as to a less extent does also the genus
Vermipora, Hall. The corallites radiate from the base in the
massive forms, from an imaginary axial line in the dendroid
types, and from an imaginary axial plane in the frondescent
species ; and their general form is more or less conspicuously
prismatic or polygonal. This is seen in almost all those
coralla in which the corallites are closely contiguous {Favo-
sites, Lam., Syringolites, Hinde, Michelmia, De Kon., Nydo-
pora, Nich., &c.) There are species, however, even of such
forms as the above, in which the corallites are subcylindrical.
In other cases (^Alveolites, Lam., Ccenites, Eichw., and some

FAVOSITIDyE. 31

forms of Pachypora, Lindstr.) the corallites are very much
compressed and flattened in form, becoming oval or sub-
triangular in shape. In other cases, again, the corallites are
partly contiguous and partly free {Veriiiipora, Hall, Romin-
geria, Nich., Ckonostegites, E. and H., &c.), and in these
cases the corallites are prismatic where in contact, and more
or less cylindrical where free. In all the Favosi tides, however,
the corallites of the colony are in contact in some portions of
their extent. Wherever contact occurs, the walls of the coral-
lites enter into a certain degree of union, though the extent of
this varies in different cases. In most of the Favositidce (in-
cluding all the typical forms) thin sections show that the
corallites always retain their proper walls, however closely
amalgamated they may appear to be ; so that the boundaries
of contiguous tubes are distinctly marked out by conspicuous
dark lines. Hence, also, weathered or fractured surfaces
usually (though not always) show the oiUsides of the coral-
lites. In one genus only (Nyctopoi'a, Nich.) the fusion of
the walls of contiguous corallites appears to be complete.

As a general rule the walls of the corallites are not specially
thickened ; but in certain types {^Pachypora, Lindstr., Striato-
pora, Hall, Trachypora, E. and H., and Ccenites, Eichw.), the
visceral chambers of the polypes become contracted by the
secondary deposition of dense sclerenchyma in concentric
lamellae, the amount of this deposit increasing as the calices
are approached. In Stenopora, Lonsd., this thickening of
the tubes takes place periodically, and the terminal portions
of the corallites become thereby periodically annulated on
their outer surface, the intervening non -thickened portions
beinor not in actual contact. In some cases this thickeninsf
of the walls of the corallites takes place to such an extent
(as in Trachypora, E. and H.) as to give rise to all the
appearances which would be produced if the tubes were
embedded in a dense " coenenchyma ; " and the existence
of such a structure has often been affirmed. Microscopic
sections, however, show that the calcareous tissue separating

32

TABULATE CORALS.

the actual visceral cavities is of endothecal origin ; and I have
seen nothing of the nature of a true " coenenchyma" in any of
the FavositidcE.

Wherever the walls of the corallites in the Favositidce come
in contact with one another, a communication between the vis-
ceral chambers of the polypes is effected by means of the
"mural pores." These are, typically, very definite apertures,
usually arranged in some serial order ; and for the most part
so small and so widely apart, that they do not appreciably inter-
fere with the compactness and integrity of the wall as a distinct
structure. In the Silurian genus Cohunnopora, Nich., the pores
are so numerous and close-set that, though regular in form and
arrangement, they give the wall a cribriform aspect ; in the
Cretaceous Koiimckia, E. and H., the pores are equally numer-
ous, but apparently irregular ; while in the Devonian Arceopora,
Nich. and Eth. jun., the trabecular condition of the wall is
quite like that of the typical Perforate Corals. In these
forms, therefore, we have a more or less complete approxi-
mation to the condition of parts in Alvcopora (fig. 13), a recent
Madreporarian, in which tabulae are developed. It is hardly

Fig- '3- — A, Vertical section n{ Aheopora sf>on^iosa, Dana, showing the porous walls and the
tabulre and (b) two calices of the same, enlarged. Recent. (After Dana.)

necessary to add that in those members of the Favositidce in
which the corallites are partially disjunct, the mural pores
only exist in places where the tubes are In actual contact.

The condition of the septa varies extremely in the Favo-
sitidce, though it is only in some few forms that these struc-

FA VOSITID^. 33

tures appear to be wholly obsolete {e.g., in Stcnopora, Lonsd.)
The most typical condition of matters is, that the septa should
be present in the form of vertically disposed rows of longer or
shorter spinules. The number of these vertical rows varies,
but is most commonly between ten or twenty. In Cceniies,
Eichw., the septa are reduced to one or more tooth-like ridges,
which appear to be confined to the thickened portions of the
tubes, close to their mouths; and in Alveolites, Lam., a similar
reduction of the septa may take place, though the walls are not
thickened, and the septa may be wholly wanting. In Ar^sopora,
Nich. and Eth. jun., the septa subdivide and anastomose with
one another to a greater or less extent ; and in Nyctopora,
Nich., they assume the form of marginal ridges or lamellae,
their typical spiniform character being lost.

Lastly, the visceral chamber in all the Favositidce is inter-
sected by a greater or less number of transverse partitions or
" tabulae." Typically, these tabulae are " complete " — that is to
say, they pass completely across the visceral chamber as so
many unbroken horizontal plates ; but this is not invariably
the case. Sometimes, however (as in Favosites hemispkei^ica,
Yand. and Shumard), the tabulae are " incomplete," having the
form of tongue-shaped laminae, which project to a greater or
less extent into the visceral chamber, often anastomosing or
dividing at their free edges, but not passing quite across the
tube. Very commonly " complete " and "incomplete" tabulae
are found coexisting ; and this is particularly the case with the
comparatively rudimentary and imperfect tabulae which occur
in many species of Favosites, and which Dr Rominger terms
"squamulae," assigning to them, as I think erroneously, a
septal origin. Finally, there are genera, such as Michelinia,
De Kon., in which the tabulae are convex, and unite so freely
among one another as to give rise to a kind of subvesicular
tissue, not unlike the cellular tissue which fills the visceral
chamber of the Cystiphy Hides, though usually much less per-
fectly vesicular, and interrupted every now and then by a
complete tabula.

c

34 TABULATE CORALS.

The zoological affinities of the FavositidcB, as has been seen,
are with the Zoantharia Perforata, and the family may find a
place close to the Poi^itidcs. The typical genera of the Favo-
sitidcB {FavositeSy Lam., Alveolites, Lam,, Mickelinia, De Kon.,
&c.) are distinguished from the typical Poritidce by the much
more complete development of the walls of the corallites, by
the reduction of the channels of communication between the
visceral chambers of contiguous polypes to comparatively
minute and for the most part serially-arranged " pores," and
by the presence of well -developed tabulae. On the other
hand, the Cretaceous Koninckia, E. and H., and the Devonian
Arcsopora, Nich. and Eth. jun., have the walls so highly cribri-
form and the tabulae so greatly reduced that they might per-
fectly well be placed in the family of the PoritidcE, in the
vicinity of the recent Alveopora, Quoy and Gaim. (fig. 13), and
Favositipora, Sav. Kent. The link between these extreme
forms is effected by such a type as the Lower Silurian Colum-
nopora, Nich., which has highly but regularly perforated walls,
combined with numerous complete tabulae and lamellar though
rudimentary septa. Another group of the Favositidcs is con-
stituted by Pachypora^ Lindstrom, Striatopora, Hall, Trachy-
pora, E. and H., Dendropora, Mich., and Cce7iites, Eichw. — in
all of which the cavities of the polypes are more or less con-
tracted by the deposition of sclerenchyma on the interior of
the walls of the corallites. Many of these forms consequently
assume an appearance extremely similar to that of the recent
Pocillopora, Lam., and Seriatopora, Lam., from which, however,
they are fundamentally separated by the absence of a coenen-
chyma and by their perforated walls. The genus Stenopora,
Lonsd., though possessing peculiarly thickened walls, exhibits
so many other anomalous features that it cannot be associated
with the preceding, but must rather be regarded as a special
type. The genus Syringolites, Hinde, though in many re-
spects entirely like a Favosites, possesses funnel-shaped tabulae,
which give rise to an axial tube in the centre of each corallite
— thus formlnof an interestino- link between the Favositidce and

FA VOSITIDAi.

35

the Syriiigoporidce. The genus Rommgeria, Nich. (= Qiienstedtia,
Rom.), is, again, curiously transitional between the Favositidcu
and the Atiloporidc^, having the mural pores of the former
combined with corallites of the general type of the latter.
Lastly, the genus Nyctopoi^a, Nich., affords a link between the
FavositidcE on the one hand, and the apparently Aporose
group of the ColumnariadcB on the other hand.

The following is a list of the genera which I include under
the FavositidcB, with the geological distribution of each. It
must be remembered, however, that two or three of these types
are at present imperfectly understood, and may prove to have
different affinities ; while two or three might with almost equal
propriety be included in the family of the Poi^itidce ; and future
researches will doubtless show that other generic forms will
have to be added to the list : —

Genus.
Favo sites, Lam.,
Alveolites, Lam., .
Vermipora, Hall, .

Miehelinia, De Kon., .

Pkurodietyian, Goldf., .
Chonostegiies, E. and H. ( - |^

Haimeophylhivi, Bill.), J

Pachypora, Lindstr.,
Striatopora, Hall, .
Trachypora, E. and H. (with \

Dendropora, Mich., and -

R/iabdopora, M'Coy), j

Ctvnitcs, Eichw., .
Coliinmopora, Nich.,
Koninckia, E. and H. .
Favositipora, Sav. Kent (?

Poritida),
Arceopora, Nich. and Eth.

Jun. (? Poritidce),
Roemeria, E. and H. (? Syr-

ingoporidce),
Syringolitcs, Hinde,
Nyetopora, Nich., .

Geological range.

Silurian to Carboniferous.

Silurian and Devonian.

Silurian and Devonian.

Upper Silurian (?), Devonian and

Carboniferous (perhaps = Pleitro-

dictyuin, Goldf.)
Upper Silurian ? and Devonian.

Devonian.

Upper Silurian and Devonian.
Upper Silurian and Devonian.

Devonian and Carboniferous.

Silurian and Devonian.

Silurian.

Cretaceous.

Recent.
Devonian.

Devonian.

Upper Silurian.
Lower Silurian.

36 TABULATE CORALS.

Genus. Geological range.

Romingaia, Nich. ( = Quen- \ ^ Devonian.
stedtta, Rominger), j

r. T J { Carboniferous and Permo-Carbonifer-

Stenopora, Lonsd. . . \ /-,\ -r, ■ ,

^ { ous ; (?) Permian also.

Billingsia^ De Koninck, . . Devonian.

Laceripora, Eichw. (imperfect- \ _ ^^^^^^ g-j^^j^,^ ^^^^ Carboniferous.

ly known), j

Nodidipora, Lindstr. . . . Upper Silurian.

An examination of the above list shows that of the twenty-
two genera placed in the FavositidcB no less than twenty are
Palaeozoic ; so that this group of Perforate Corals enjoyed,
therefore, a great extension at this early period. Koninckia
is the only Cretaceous genus, and Favositipora the only recent
one ; and both might find a place in the PoiHtidce, near Alveo-
pora. Moreover, the group attained its maximum develop-
ment in Upper Silurian and Devonian times; very few types
survive into the Carboniferous period ; and perhaps the only
one existing in the Permian is Stenopora. Indeed the great
abundance of these Palseo-Perforate Corals in the Devonian,
and their very scanty representation in the Carboniferous, may
be taken as one of the strongest of the palseontological proofs
that the periods so named are geologically distinct. Lastly, the
almost total absence of examples belonging to the Favositidce
in Secondary and Tertiary deposits affords an indication that
the family is more than a mere sub-group of the now widely
distributed Poritidce.

37

CHAPTER III.

GENERA OF FAVOSITID^.

Gcmis Favosites, Lamarck, 1816.

(Hist, des An. sans Vert., vol. ii. p. 204.)

Calamopora, Goldfuss, Petref. Germ., vol. i. p. 77, 1826.

Emmonsia, Milne-Edwards and Haime, Pol. Foss. des Terr. Pal., p. 246, 1851.

Astrocerium, Hall, Pal. N.Y., vol. ii. p. 120, 1851.

Gen. Char. — Corallum massive or branched, composed of nu-
merous more or less conspicuously polygonal corallites, which
are in close contact with one another, but are not amalga-
mated by their walls. Walls lamellar, perforated with one
or more rows of circular " mural pores," by which the separate
corallites are placed in communication. Visceral chamber in-
tersected by a greater or less number of complete or incom-
plete transverse partitions or " tabulae." Septa obsolete, or
represented by vertical rows of tubercles or pointed spines.

The general form of the corallum in this genus is very vari-
able, but the most typical species (^.^., F. Gothlandica, Lam.)
possess a discoidal, hemispherical, or subglobular skeleton, of a
massive character, and often attaining very considerable dimen-
sions. Other forms, again, have the habit of growing in cylin-
drical or flattened ramose expansions; but most of the so-called
" dendroid " species of Favosites may be placed under allied
generic types. The forms with a discoidal or expanded, and

38 • TABULATE CORALS.

those with a hemispherical or globose corallum, have the lower
surface covered with a thinner or thicker, concentrically-striated
epitheca, while the calices are placed upon the upper surface.
The ramose species possess no true epitheca.

In the massive and more typical species the corallum Is fixed
by a portion of its base to some foreign body ; and from this
point the long and prismatic corallites radiate to the surface,
those in the centre of the mass being nearly vertical in direc-
tion, while those towards the margins become more and more
inclined, till they become nearly or quite parallel with the
lower surface. New corallites are intercalated by gemmation,
as the tubes proceed towards the surface. In the ramose
species, the corallites are vertical in the centre of the branches,
and gradually bend outwards, in a radiating manner, till they
open on the circumference in a direction more or less nearly
rectangular to the surface.

The corallites are typically markedly prismatic, usually pen-
tagonal or hexagonal, but they may become more or less cylin-
drical in whole or in part. The tubes are never united by the
actual fusion of their walls, though always In contact, and
their walls are typically of no great thickness. In some forms,
however, which have been commonly referred to Favosites, but
which will here be placed under the allied genus Pachypora,
Lindstrom, the walls are extraordinarily thickened by a second-
ary deposit of sclerenchyma, and we find an approximation to
this in some species which must still be left in Favosites proper.
In all the species of Favosites, further, the visceral chambers of
contiguous corallites are placed In communication by means of
a series of circular apertures or " mural pores." These fora-
mina are usually arranged in a regular manner ; and though
this arrangement is not absolutely constant for, perhaps, any
given species, still it is approximately uniform in its character,
and thus affords a useful guide in specific diagnosis. Thus, in
certain species {e.g., F. turdinata, Bill.) the pores are typically
unlserial — that Is to say, each of the flat faces of the prismatic
corallites carries a single row of these apertures. In another

GENERA OF FA VOSITID^. 39

series of types {e.g., F. Gothlandica, Lam.) the pores are bi-
serial, each prismatic face of the coralHtes carrying two rows,
usually placed alternately. In other forms, again, the pores
are triserial ; while some species {e.g., F. alveolai^is, Goldf., and
F. aspera, D'Orb.) are distinguished by the peculiarity that the
pores are situated in the angles formed by the prismatic walls
of the corallites, instead of on their flat faces. Very commonly
the pores are surrounded each by a raised rim or margin, but
this may be replaced by a circular pit, or the surface may be
quite plane. It should, lastly, be noticed in this connection,
that the mural pores are commonly very difficult of detection,
even in specimens otherwise perfectly well preserved, by even
the closest external examination. Very commonly in calca-
reous specimens, and sometimes in those which are silicified
(especially in those where the silica has assumed the " orbicu-
lar" form), the walls of the corallites appear to be completely
imperforate under a hand-lens, or even under the microscope.
Thin sections, however, when taken parallel with the axis of
the tubes, will generally, in some part or another, coincide with
the plane of the wall of a corallite, and will then exhibit the
mural pores with greater or less distinctness.

The calices of the typical species of Favosites are placed
parallel with, and not elevated above, the general surface ; but
in some forms which have not yet been clearly separated from
this genus, the calices open more or less obliquely to the surface,
and the lower lip of the calice is more or less elevated and pro-
jecting. In a few singular types {F. turbinata, Bill., F. For-
besi, var. tuberosa, Rom., F. claiisus, Rom., &c.) there is the
sinofular feature that the calices in a laro-er or smaller number
of the corallites become closed by a calcareous lid or " opercu-
lum." Sometimes this seems to be merely the result of a con-
tinuous growth of the epitheca upwards ; but in other cases
the operculum would seem to be formed by successively
deposited concentric layers of calcareous matter, which spring
from the margins of the calice, and gradually close in towards
its centre. In the species above mentioned — all of which are

40 TABULATE CORALS.

Devonian — this curious feature seems to be one normal to the
species, being more or less fully developed in all perfect ex-
amples. In other species, however, it would appear to be only
an occasional phenomenon. Dr Lindstrom has recognised the
same peculiarity — as an occasional thing — in examples of the
Upper Silurian F. Forbcsi, E. and H., and also in his Verinipora
{Fletcherid) clmisa, from the same formation (Ofversigt af K.
Vetensk. Akad Forhandlingar, 1865, PI. XXX.)

Septa are so commonly obsolete in Favosites, or are so
rudimentary, that these structures were supposed to be gener-
ally altogether absent in the species of this genus. In reality,
however, the septa must be regarded as constituting one of the
most variable of the structures of a very variable group, and
not even specific value can be attached to their presence or
absence, or to the degree of their development when present.
In some cases there are absolutely no traces of septa, even in
specimens examined by means of microscopic sections. More
commonly the septa can be recognised as so many longitudinal
striae or ridges on the interior of the tube, each ridge being
really made up of a vertical series of tubercles. In other cases,
again, the septa have the form of radiating spines, which may
reach very nearly to the centre of the visceral chamber, though
usually considerably shorter than this. In no case are regular
lamellar septa developed. All the above conditions of the
septa — namely, their presence as radiating spines in superposed
rows, their development as tubercles arranged in ridges, or
their total absence — may be occasionally recognised in different
examples of the same species, or even in different parts of the
same specimen. The number of the septal ridges or spines,
when developed at all, is not constant, but appears to be most
commonly from twelve to fifteen.

The genus Astrocerium, Hall {loc. cit.), was founded upon
examples of Favosites, in which spiniform septa are developed ;
but the variability of this character renders this division an
untenable one.

The tabulae in the most typical forms of Favosites are com-

GENERA OF FAVOSITID.E. 41

plete transverse partitions, which are placed at variable
distances, and rarely anastomose. Most usually, the tabulae
are approximately horizontal ; but they may be markedly con-
vex or concave. Certain species {F, favosa, Goldf.) have been
distinguished by the curvature of the tabulae ; but this appears
to be a very variable character, differing even in different parts
of the same specimen, and it cannot be employed in the diag-
nosis of species. Similarly, it is not uncommon to find that
the tabulae are so bent as to ijive rise to a series of marginal
pits or depressions, which in some specimens are extremely
regular, and impart an apparently characteristic appearance to
the tubes. This feature, however, is also not constant, even
in the same individual, and cannot be looked upon as of
specific value.

While the typical species of Favosites possess " complete "
tabulae, there are others in which these structures have the
form of imperfect plates, which extend into the visceral cham-
ber transverse to its axis, but do not divide it into a succession
of completely separate vertical storeys. These " incomplete "
tabulae were regarded by Milne-Edwards and Haime as being
of generic value, and these authors placed all those forms
possessing them in the genus Einmoiisia {loc. jam ciL) The
fact, however, that it is by no means uncommon to meet with
single specimens in which some of the tubes have the irregular
and incomplete tabulae of Emmonsia, while others have the
regular and complete tabulae of the type-forms of Favosites —
the same tube sometimes exhibiting both these conditions in
different parts of its course — is quite sufficient to show that the
separation of Emmonsia as a distinct genus cannot be carried
out in practice.

Lastly, there are various species of Favosites in which, in
addition to, or in the absence of, complete tabulae, the inner
surfaces of the tubes are rendered rough by the presence of
numerous horizontal projecting lamellae, which extend only a
short distance into the visceral chamber, and which often have
a more or less leaf - like or tono^ue-like character. These

42 TABULATE CORALS.

singular structures — the " squamulae " of Dr Rominger — are
particularly characteristic of certain Devonian forms, but they
occur also in the Upper Silurian F. For best. We cannot,
therefore, accept the statement made by Dr Rominger (Foss.
Cor. of Michigan, p. 19), that "the Silurian forms differ from
the Devonian Favosites by invariably having simple dia-
phragms, and by the spinulose character of their radial crests."
At least one Silurian species of the genus, on the contrary, is
known to possess imperfect tabulae as a variation ; and many
forms exhibit no septa (" radial crests ") at all, or only rows of
tubercles. Nor can we accept the view held by Dr Rominger,
that the " squamulae" of certain species of Favosites are really
of the nature of septa. On the contrary, the fact that their
direction is one transverse to the axis of the visceral cavity,
and that they commonly occupy the entire width of one of the
prismatic faces of a corallite, entirely precludes our believing
that they can have been situated in the inside of one of the
" mesenteries " of the living animal, and is thus fatal to the con-
ception of their septal character. They must, on the other hand,
be regarded as a peculiar modification of the tabiUcB of the more
typical species, and they not uncommonly coexist with these.

In no case known to me are the tabulae of Favosites in-
fundibuliform, or invaginated one into the other ; and this
leads me to say a few words as to the genus Calamopora of
Goldfuss, and as to the propriety of the course followed by
many Continental palaeontologists in substituting the latter
name for the former. The actual definition of Calamopora
given by Goldfuss (Petref. Germ., p. 72) is as follows : —

** Stirps calcarea, e tubis p^Hsmaticis parallelis contiguis
divergent! bus. Tiibi diapln^agmatibus transversis {e siphone
prolifero) inter septi, et poris lateralibus communicantesJ'

Not only do his subsequent descriptions and figures render
it certain that the forms included under this head by Goldfuss
are precisely the same as those long before placed by Lamarck
under Favosites, but he himself admits this ; and the only new
characters which he gives are to be found in the words "e siph-

GENERA OF FA VOSITID^. 43

one prolifero," as indicating the structure of the tabular. Gold-
fuss himself, however, in the vernacular description which
follows the brief Latin diagnosis, confesses that " nur bei einer
Art erscheinen sie" (the tabulae) " als trichterformige Prolifera-
tion eines Sipho." The one species to which he alludes is his
Calamopora infiindibidifera, which is in all its characters very
distinct from the older genus Favosites of Lamarck, and which
is only very doubtfully referable to the family of the Favositidce
at all, since it has never been proved to possess mural pores.
Nor can it even be asserted that the tabulae in this type spring
from or form an actual central tube or " siphon " — they simply
appear to be funnel-shaped and invaginated. Considering,
then, that all the other species included by Goldfuss under
Calamopora are undoubtedly destitute of the median siphon
implied by this generic name, and that most of them are clearly
identical with the forms previously designated Favosites by
Lamarck, it does not appear that there is the slightest ground
for the course adopted by some of the most distinguished of
living German palaeontologists, who still regard Favosites,
Lam., as a mere synonym of Cala7nopora, Gold.

I shall have occasion, however, to point out subsequently
that there really does exist a coral {Syringolites, Hinde) which
actually possesses the median tube imagined by Goldfuss to
be present in his Calamopora, and for which, therefore, this
name might be retained, if it were at all advisable to try and
revive a genus founded upon so many forms of different affin-
ities. The coral in question, however, in no way agrees with
any of the forms included by Goldfuss under the head of Cala-
mopora— not even with C. infundibulifej^a, now known as
Ro^mei'ia infundihilifcra; and it is fully entitled to receive the
new generic designation Syringolites, Hinde, under which name
I shall briefly describe it later on.

Of the other genera of the Favositidce, Alveolites, Lam.,
Pachypora, LIndst., and Striatopora, Hall, are probably those
which are most difficult to separate from Favosites proper.
Palaeontologists have recently shown a tendency to suppress

44 TABULATE CORALS.

Alveolites altogether, as including types of very different
affinities ; but the name may be advantageously retained, in the
meanwhile at any rate, for forms like A. suborbicularis. Lam.;
though it is difficult to point to any characters which definitely
separate these from Favosites except their inclined corallites and
oblique calices. Pachypora and Striatopora^ again, are hardly
separable from the dendroid forms of Favosites by anything
else except by the thickening of the walls of the corallites near
their mouths; and, in fact, even this distinction would fail
unless we remove from the latter category, as will here be
done, some forms which are usually included in it (such as
F. cristata, E. and H., and F. cervicornis, De Blainv.) The
position of Cladopora, Hall, I shall consider in dealing with
Pachypora. Fistulipora, M'Coy, can in general be readily dis-
tinguished from Favosites, both by the existence of two distinct
series of corallites, and by the absence in the former of mural
pores. There is, however, one species — viz., Favosites {Fistu-
lipora) Canadensis, Bill., from the Devonian of Canada, which
ordinarily has all the external features of Fistulipora, but which
has been shown by Rominger to possess the mural pores of
Favosites, a fact which I can corroborate from an examination
of microscopic sections. Moreover, this transitional form some-
times loses the characteristic of possessing a series of large
corallites interspersed among numerous smaller ones, and
passes by insensible gradations into a type so similar to the
ordinary examples of Favosites, that it has been separated by
Dr Rominger, as I think without sufficient reason, to constitute
a new species under the name of F. placenta (Foss. Cor. of
Michigan, p. 32).

Michelinia, De Kon., is another close ally of Favosites, for
I am unable to agree with Dr Lindstrom in thinking that there
is any essential difference in the nature of the mural pores in
these two genera (On the Affinities of the Anthozoa Tabulata,
Ann. and Mag. Nat. Hist., sen 4, vol. xviii. p. 12). It differs
from Favosites almost exclusively in the complex character of
its tabulae.

GENERA OF FA VOSITID.E. 45

Syringolites, Hinde, while possessing the general structure
and habit of Favositcs, is entirely separated from it by the fact
that the tabulae are infundibuliform, giving rise to a central
tube in the axis of the visceral chamber of each corallite ; the
genus thus forming a connecting-link between Favosites and
certain forms of Syi'ingopora.

Lastly, Coliirnnopora, Nich., is closely allied to Favosites,
but is distinguished by the less intimate union of the corallites,
and by the greater development of the system of mural pores,
the walls thus becoming completely cribriform.

As regards the geological range of Favosites, it may be stated
with certainty that the genus attained its maximum during the
Upper Silurian and Devonian periods. It probably existed
durinof the Lower Silurian, thougrh the evidence available on
this point is not absolutely satisfactory ; and it was certainly
continued into the Carboniferous. The existence, also, of a
recent coral which is hardly separable from Favosites proper —
namely, the Favositipora of Saville Kent — would indicate that
the genus will yet be found in the Secondary and Tertiary
deposits, either unmodified or under some allied form. Koninc-
kia, E. and H., of the White Chalk, differing from Favosites
chiefly in its larger and more approximated mural pores, offers
one of these desired continuations of this ancient Coelenterate
type ; and my friend Professor C. A. White has recently shown
me a coral from the Cretaceous deposits of North America,
which assuredly could not be separated from Favosites otherwise
than by the apparent — possibly only apparent — absence of
mural pores.

As illustrative species of Favosites, I have selected F. Got/i-
landica. Lam., F. Forbesi, E. and H., /^ {Emrnonsici) hemispher-
ica, E. and W., F. {ChcEtetes) Boivcrbaiiki, E. and H., and F.
clausa, Rom. — the first three of these being massive forms,
while the last is a true dendroid species, and F. Bowerbanki
offers a transition between these two types.

46 TABULATE CORALS.

Favosites Gothlandica, Lamarck.^

(PI. I., figs. 1-6.)

Favosites Gothlandica, Lamarck, Hist, des An. sans Vert., vol. ii. p. 206, 1816.
Calainopora Gothlandica, Goldfuss, Petref. Germ., PI. XXVI., figs. 3 fl-, 3 b,

2, c, T, e (cset. exclusis), 1829.
„ favosa, Goldfuss, Petref. Germ., PI. XXVI., 2 a-2 c, 1829.

Favosites Goldfussi, D'Orbigny, Prodr. de Paleont., vol. i. p. 107, 1850.
„ Gothlandica, M'Coy, Brit. Pal. Foss., p. 20, 1851.
„ Gothlandica, Milne-Edwards and Haime, Pol. Foss. des Terr. Pal.,
p. 232, 1851 ; and Brit. Foss. Cor., p. 256, PI. LX., figs, i, i a,
1854.
„ Goldfussi, Milne- Edwards and Haime, Pol. Foss. des Terr. Pal.,
p. 235, PI. XX., fig. 3, 185 1 ; and Brit. Foss. Cor., p. 214, PI.
XLVIL, figs. 3-3^, 1853.
„ Niagarcnsis, Hall, Pak N.Y., vol. ii. p. 125, PI. XXXIV., a, bis,
fig. 4, 185 1.
favosa (?), Hall, ibid., p. 126, Pk XXXIV., bis, fig. 5, 1851.
Calamopora Gothlandica, Ferd. Roemer, Sil. Fauna des Westlichen Tenn.,
pp. 18 and 19, figs. 9-9 <^ and 11, i860.
,, favosa, Ferd. Roemer, ibid., p. 18, fig. 8, i860,

Favosites Gothlandica, Billings, Canad. Journ., new ser., vol. iv. p. 99, 1859.
„ Gothlandica, Nicholson, Report on the Palfeontology of Ontario,

1874, P- 45-
„ favosa, Nicholson, ibid., 1875, p. 51.

,, favosa, Nicholson, Palaeontology of Ohio, vol. ii. p. 229, 1875.
„ favosus, Rominger, Fossil Corals of Michigan, p. 20, Pk IV., figs.

1-4, and Pk v., fig. 2, 1876.
„ Niagarensis, Rominger, ibid., p. 22, Pk V., fig. i.
„ Winchelli, Rominger, ibid., p. 31, Pk IX., figs. 3 and 4, and Amer.

Journ. Sci. and Arts, 1862.
„ Billiiigsii, Rominger, ibid., p. 28.

Spec. Char. — Corallum composite, forming discoidal, spher-
oidal, turbinate, or hemispherical masses of irregular shape and
size, the under surface being usually covered with an epitheca,
while the whole of the upper surface is occupied by the calices.
Corallites prismatic, usually between one line and one and a

^ In the list of references appended to this, as well as to the other species subse-
quently described, I have not attempted to give an absolutely exhaustive synonymy.
On the contrary, I have simply given those references which I have myself verified.
In some cases, of course, my verification has been based simply upon an author's
description or figures, and must therefore be considered merely as an expression
of personal opinion. In the majority of cases, however, my determination has
been founded upon an examination of actual specimens derived from the same
formation as that which yielded examples to the author quoted.

GENERA OF FA VOSITID^E. 47

half line in diameter, sometimes less, and often more. Calices
regularly polygonal, with thin walls, generally tolerably uniform
in size in any given specimen, but always having smaller and
younger ones intercalated among those of average size. Walls
of the corallites not thickened towards their mouths, sometimes
longitudinally striated on their flat faces, and furnished with
two (sometimes one or three) rows of mural pores on each
prismatic face. Pores alternately placed, surrounded by an
elevated margin. Tabulae complete, rarely inosculating ; some-
times incomplete and inosculating in parts of a colony, while
complete in others. Septa usually obsolete or irrecognisable,
sometimes represented by rows of tubercles or even by well-
developed radiating spines.

Obs. — If the forms which I have here admitted under the
head of F. Gothla7idica, be really referable to this form, then it
must be allowed that we have to deal here with one of the most
variable species of a variable genus. All the above, however
(with some others not included in this list), are clearly descen-
dants of a single stock, belonging to the same type-form, differ-
ing only in characters of comparatively trivial importance, and
for the most part insensibly passing into one another by the
intervention of examples possessing intermediate characters.
Some of the forms included in the series are so far distinct
that they may well retain distinct varietal appellations ; but
their general relationships are so close that I have thought it
best to collect them under a single specific title, rather than
to follow some high authorities in treating each as a separate
species. :

Favosites Gothlaiidica was originally described from speci-
mens found in the Wenlock Limestone of the island of Got-
land (Lamarck, loc. cit.), and this name was restricted by
Milne-Edwards and Haime to forms occurring in the Silurian,
the species not being admitted as a Devonian one. We may
therefore properly regard the form which occurs so commonly
in the Upper Silurian of Europe, and which palaeontologists
have so long recognised under the name of F. Gothlaiidica,

48

TABULATE CORALS.

as the type of the species. Examples specifically inseparable
from this are, however, found in the Devonian of both the
Old and New Worlds ; so that the species had a very wide

Fig. 14. — ^A, A specimen oi Favosiles Gothlandica, Lam., ficjm ihe Niagaia Limestone (Wen-
lock) of Owen Sonnd, Ontario, of the natural size ; B, A small example of the same
species from the Wenlock Limestone of Dudley, with comparatively minute corallites,
of the natural size ; C, Fragment of the same species, with large-sized corallites, from the
W'enlock Limestone of Gotland, of the natural size ; D, Part of two corallites of the
same species, from the Corniferous Limestone (Devonian) of Woodstock, Ontario,
slightly enlarged.

range both in space and in time : and there are various other
Silurian and Devonian forms of Favosites which, as before said,
appear to be nothing more than variations of this type-form.
Having had the opportunity of making a careful examination,
microscopic and macroscopic, of a very extensive series of such
forms, collected from the Silurian and Devonian deposits of
both America and Europe, I shall in what follows briefly
record the results of my researches as bearing upon the
structural characters of the species.

GENERA OF FA VOS/TIDAi.

49

The general shape of the corallum of Favositcs Gothlaiidica
is very variable ; and its size differs still more either in speci-
mens of different ages, or in specimens derived from different
formations. Typical examples, from the Upper Silurian, are
generally more or less hemispherical or discoidal, with a de-
pressed or slightly convex upper surface (fig. 14, b), the cor-
allum being attached to some foreign body by the centre of
its base, which is sometimes drawn out into a short peduncle.
The lower surface is also covered with a thin, smooth, or con-
centrically-striated epitheca, which is commonly worn ofT in
old specimens, though sometimes greatly thickened. Average
examples of this kind are usually two or three inches in dia-
meter, sometimes more, with a height of three quarters of an
inch to an inch ; but I have figured a small example — the
youngest I have seen — from the Wenlock Limestone of
Dudley, in which the diameter is only about eight lines, with
a height of three lines (PI. I., fig. 3). In the Devonian, the
species seems to have assumed a much greater luxuriance of
growth, examples of much larger size and of very variable form
being far from uncommon. Even the larger specimens, how-
ever, seem to preserve the same general type — namely, that of
a flattened or hemispherical expansion, attached by a portion of
its base, and having its inferior surface covered by an epitheca.

The corallites in the typical Upper Silurian examples of F.
Gothlandica are prismatic, thin-walled, usually pentagonal or
hexagonal, and very regular in form and size in any given
example {see fig. 14, a and b, and PI, I., figs, i and 2). The
calices, of course, have a corresponding polygonal form and
regularity of outline ; and here we seem to reach one of the
most distinctive characters of the species. It need hardly be
said that in no specimen are the corallites absolutely uniform
in size or form. In every individual example, the corallum
consists of younger and older, and therefore of smaller and
bigger, tubes, and the form of these necessarily varies with
variations in the pressure to which each is subjected by its
neighbours. Still, the average corallites of any particular speci-

50 TABULATE CORALS.

men of F. Gothlandica are wonderfully similar in size and
shape, being strikingly and often regularly pentagonal or hex-
agonal, and being further distinguished in thin sections by the
thinness of their walls (PI. I., figs, i and 2). In no case do the
larger calices assume the rounded character of those of F. For-
besi, nor is there the same conspicuous interpolation of small
tubes among the larger ones. All the forms which I have
here included under F. Gothlandica agree in the possession of
these regularly prismatic, thin-walled tubes ; and this being the
case, it remains to be considered if the size of the average
corallites can be properly considered as a specific character.
Most palaeontologists have answered this question in the affir-
mative, and have given names to species separated from the
typical F. Gothlandica principally or solely on account of the
average size of the corallites. Mr Billings, however, long ago
gave reasons for thinking that this character was one upon
which little stress could be laid (Canad. Journ., new sen, vol.
iv.), and my own researches have led me to entirely coincide in
this opinion. The examples which I have examined from the
Upper Silurian, and about the determination of which I enter-
tain no doubt, show conclusively the small weight that can be
attached to the mere size of the corallites. Those from the
Wenlock Limestone of Dudley, Longhope, and Benthall Edge,
have tubes of an average size of one line, some a little less,
some a little more (as stated by M'Coy, and also by Milne-
Edwards and Haime in their Monograph of the British Fossil
Corals). Those from the Wenlock Limestone of Gotland
(kindly sent to me and specifically determined by my friend
Dr Lindstrom) have usually a diameter of from one and a half
to two lines (agreeing, on the whole, with the measurements
given by Milne- Edwards and Haime in their work on the
Polypiers fossiles des terr. Pal.) ; but in one example the
tubes have a diameter of fully three lines (fig. 14, c). Lastly,
■hose from the Niagara Limestone (Wenlock) of North Amer-
ica have mostly tubes of an average diameter of a line and a
half, this being sometimes reduced to a line or less, or increased

GENERA OF FAVOSITIDAL. 51

to three lines (PI. I., figs. 4 and 5). The Devonian examples
which I should place in this species, possess an equal variability
in this respect; and it is therefore clear that the diameter of
the corallites — even when we look only to the ave7'age tubes
of a given specimen — cannot, in the case of F. Gotklandica,
be regarded as a character of specific value. It is further clear
that forms said to be specifically distinct from F. Gotklandica
must be proved to possess some character of greater constancy
and persistence than the mere size of the average corallites,
before their claims for separate recognition can be allowed.

The ivalls of the corallites of F. GotJilandica usually have
the outer surface smooth, or marked with delicate transverse
lines, which indicate the position of the tabulze within. In
specimens, however, which cannot be otherwise separated from
F. Gotklandica (as previously shown by Mr Billings, loc. citi),
it is not unusual to find the flat outer faces of the corallites
exhibiting one or two longitudinal lines or striae separating
the rows of mural pores. This Is the chief or only character of
Importance which Milne-Edwards and Halme adduce In their
definition of F. Troostii, as separating this species from allied
forms ; and Its occurrence in well-marked Devonian examples
of F. Gotklandica — as here understood — ^would seem to greatly
diminish or altogether destroy its value as a test of specific
distinctness.

The imiral pores of all the typical examples of F. Gotklan-
dica, both from the Upper Silurian and Devonian, are arranged
in a double row upon each of the prismatic faces of the coral-
lites, those of the two rows alternating with one another, and
each being separated from Its neighbour by a space of about
half a line, measured vertically, and surrounded by a slightly
raised rim or border (fig. 14, d). These are certainly the
general characters of the mural pores in F. GotJilandica, and
they would serve as admirable guides to a specific determina-
tion If they could be at all constantly determined, or were In
themselves constant In their occurrence. In a great many
specimens, however, even though apparently excellently pre-

52 TABULATE CORALS.

served otherwise, and whether calcareous or siHcified, it is quite
impossible to determine the arrangement of the mural pores,
or even to satisfy one's self of their existence ; while microscopic
sections afford only a casual help, since they do not show these
openings except when and where they happen to coincide with
the plane of one of the bounding walls of a corallite. More-
over, the arrangement of the pores does not seem to be abso-
lutely constant, as has been already pointed out by M'Coy and
by Billings ; though, of course, one is here confronted with the
difficulty that it is open to any one to assert that all specimens
in which the mural pores are not biserial are not specimens of
F. GotJdandica, but are referable to some distinct species, even
though their other characters are identical with those of the for-
mer type. I can, for instance, quite corroborate the observation
of Mr Billings [loc. cit.) that specimens apparently inseparable
from F. Gothlandica in other respects, occur in the Devonian
rocks of North America, in which the prismatic faces of the
corallites bear sometimes one, sometimes two, and sometimes
three rows of corallites, but for the most part two. Such
specimens, according to the views of Milne - Edwards and
Haime, ought to be separated from F. Gothlandica as a distinct
species {F. Goldfussi) ; but it appears to me — though it is only
with much diffidence that I differ from the views of such justly
distinguished authorities — that the mere fact of such great varia-
tion in a single specimen is strong proof that the character itself
is liable to much variation, and is not, therefore, of specific im-
portance. With regard to F. basaltica, Goldf., which resembles
F. Gothlandica in general features, but is stated to possess
uniserial mural pores, I can express no definite opinion, for I
have seen no specimens with this character. Unquestionably,
if it were shown that there existed a species of Favosites in
other respects like F. Gothlandica, but uniformly possessing
but a single row of pores on each of the prismatic faces of the
corallites, there would be good grounds for regarding this as a
distinct species ; but the evidence — or want of evidence — on
this point, would at present rather lead one to believe that

GENERA OE EA VOSITIDAs. 53

M'Coy and Lonsdale were right in regarding F. basalt ica,
Goldf., as a mere variety o( F. Gothlandka.

The tabiUce in F. Gothlandka are typically " complete " — •
that is to say, they pass completely from one side of the
visceral chamber to the other. I am able, however, from
specimens in my own possession, to entirely corroborate the
statement of Mr Billings (Canad. Journ., new sen, vol. iv. p.
102, fig. 2) that single examples, otherwise inseparable from
this species, exhibit in certain tubes the complete and compara-
tively remote tabulae characteristic of F. Gothlandica and its
allies ; while in others they show the incomplete, close-set, and
interlocking tabulae of F. hemispherica, Yand. and Shumard, in
virtue of which this latter was raised by Milne-Edwards and
Haime to the rank of a distinct genus {Emniousia). In type-
specimens of F. Gothlandka from the Upper Silurian, there are
generally six to eight tabulae in the space of two lines ; but this
number may be exceeded, or may not be reached. Ordinarily
the tabulae are more or less flat and horizontal, but they are
very commonly conspicuously arched upwards, or more rarely
concave. The specimens with convex tabulae have usually
been separated as a distinct species, under the name of F.
favosa, Goldf. ; but a careful examination of a large number of
examples has led me to agree with Dr Rominger in thinking
that this character is very variable, and that it cannot be relied
upon as a specific distinction. Another peculiarity not uncom-
monly present is, that the tabulae are bent downwards at their
periphery into a series of infundibuliform depressions, giving to
the upper surfaces of the diaphragms a plicated or sinuated
appearance (PI. I., fig. 4). There are very often twelve of
these marginal depressions ; but there may be more or fewer,
and they are generally easily to be recognised in thin transverse
sections of the corallum (PI. I., fig. 2).

Lastly, the condition of the septa in F. Gothlandka is as
variable as that of the other elements of the corallum. In
most of the specimens the septa are quite obsolete, or can only
be recognised by the practised eye as minute inequalities of the

54 TABULATE CORALS.

inner surfaces of the walls of the corallites, arranged in vertical
series. In other cases, the septa have the form of delicate but
unequally distributed spinules, which roughen the interior of
the tubes. Finally, there are specimens in which the septa
are so far developed as to assume the form of regular radiating
spines (PL I., fig. 5), which may extend nearly to the centre of
the visceral chamber, and are usually from twelve to fifteen in
number. It is upon examples of this kind that Professor Hall
founded his genus Astrocerium; but there can be no doubt that
these forms with spiniform septa are simply a varietal condi-
tion of this and other species of Favositcs.

Before leaving this species, it may be as well to make a few
remarks upon some of the forms which I have included under
it. As has been previously said, F. Gothlandica was regarded
by Milne- Edwards and Haime as essentially a Silurian species,
and the corresponding Devonian forms were separated by them
under the name of F. Goldfiissi. This latter species Is sep-
arated by its authors from F. Gothlandica simply upon the
ofround that its corallites are said to be larofer, and that the
mural pores are more closely set than in the Silurian form.
The size of the tubes (one and a half line) is, however, fre-
quently exceeded by typical Upper Silurian examples of F.
Gothlandica, and, under any circumstances, cannot be regarded
as a character of the smallest specific value, while the mural
pores exhibit at least an equal variability. I am therefore
quite unable to accept the separation of F. Gold/icssi from
F. Gothlandica.

F. favosa of Goldfuss has at first sight more claims for
separation from F. Gothlandica, the strong convexity of the
tabulae (which led Milne-Edwards and Haime to speak of their
possessing a small central columellar eminence) being a very
marked feature in some specimens, which otherwise entirely
agree with the latter form. The arching of the tabulse is, how-
ever, very variable, and one and the same specimen may
exhibit both convex and flat tabulae ; so that in the absence
of any distinctive character of a more constant nature, I think

GENERA OF FAVOSITIB.E. 55

F. favosa, Goldf., must be united with F. Gothlaiidica, Lam., or
at most retained as a distinct variety.

F. Niagarensis, Hall, from the Niagara group of North
America, seems to be certainly founded upon young speci-
mens of F, Gothlandica ; and it is possible, as Mr Billings
thinks, that Astrocerium parasiticum, Hall, and A. pyrifomne,
Hall, really belong to the same species. Upon this latter
point, however, I can offer no opinion.

Favosites Winchclli, Rominger {loc. cit), is founded upon
forms from the Corniferous and Hamilton groups (Devonian)
of North America, which agree with F. Gothlandica in all
general features, but have large tubes (one and a half to two
lines in diameter), which are occasionally somewhat rounded,
while there are only three or four tabulae in the space of two
lines. After examining excellently preserved examples from
Canada, I am unable to regard this as more than a varietal
form of F. Gothlandica.

Lastly, the name of F. Billingsii has been given by Dr
Rominger to a form of Favosites which occurs commonly in the
Hamilton group of Ontario, and which grows in large convex
discs, varying from one, two, or three inches up to as many
feet in diameter. The corallum is attached to some foreign
body by a point usually placed in the centre of the base, and
the entire lower surface is covered by a striated epitheca.
The corallites vary from a line to a line and a half in diameter ;
and though of the same essentially prismatic or polygonal form
as in typical examples of F. Gothlandica, they are slightly less
rectilinear and more irregular in shape and size than in the
latter (PL L, fig. 6). Dr Rominger states that the mural pores
are uniserial, and they often are so ; but they are just as
commonly arranged in two alternating rows, as in F. Gothlan-
dica, and the tabulae resemble those of that species. I have
figured a transverse section of this form for comparison with
the typical F. Gothlandica, and need only say that as examined
in this way the trivial difference in the form of the corallites is
much more conspicuous than it is when the calices of the two

56 TABULATE CORALS.

are compared together. To the supposed peculiarities in its
mode of growth, I think no weight can be attached, as F. Goth-
landica has commonly a similar habit ; and there are no other
points of separation worth alluding to. Upon the whole, after
minutely examining F. Billmgsii, in the ordinary manner and
by means of microscopic sections, I cannot consider it as more
than varietally distinct from F. GotJilandica, of which it may
be regarded as a local variation.

Formation and Locality} — Upper Silurian (Wenlock Lime-
stone), Dudley and Benthall Edge; also near Shalloch Mill, Gir-
van. Wenlock Limestone, Godand. Niagara Group (Wenlock
Limestone), Owen's Sound and Manitoulin Island, Ontario.
Guelph Formation (Upper Silurian), Cedarville, Ohio. Corni-
ferous Limestone (Devonian), Port Colborne, Woodstock, and
various other localities in Ontario ; also in the same formation,
Phelps, State of New York. Hamilton Formation (Devonian),
Erie Co., State of New York, and Arkona, Ontario (van Bit-
lingsii, Rom,) The species is quoted by Milne-Edwards and
Haime from the Caradoc sandstone of Britain (Mon. Brit. Foss.
Cor., p. 257) ; but I have never seen any example from strata
of Lower Silurian age. It is generally regarded as one of the
most abundant and characteristic of the Upper Silurian Corals ;
but my own experience would, so far as it goes, be in favour of
considering F. Fo7'desi, E. and H., as by far the commoner of
the two in the Upper Silurian of Britain, while F. Gotklandica
appears to attain its maximum in the Devonian.

Favosites Forbesi, Edwards and Haime.
(PI. I, fig. 7; PI. II., figs. 1-3 ; PI. III., figs. I, 2.)

Calamopora basaltica (pars), Goldfuss, Petref. Germ., vol. i. p. 78, tab. xxvi.,

figs. 4 rt;-4 ^, 1829.
Favosites Gotklandica, Lonsdale, in Murchison's Silurian System, p. 682, PI.

XV., bis, figs. 3, 4, 1839.
„ Forbesi, Milne - Edwards and Jules Haime, Pol. Foss. des Terr.

Pal., p. 238, 185 1.

• Under this heading I shall, as a rule, only give those localities from which I
myself possess specimens. When this rule is departed from, the name of the author
on whose authority the reference is given will be appended in brackets.

GENERA OF FAVOSITIDrE. 57

Favositcs Forbesi, Milne-Edwards and Jules Haime, Brit. Foss. Cor., p. 258,

PL LX., figs. 2-2 g, 1854.
,, hasaltica (pars), Billings, Canadian Journ., new ser., vol. iv. p. 106,

1859. _
„ Forbesi, Nicholson, Report on the Palaeontology of Ontario, p. 48,

PL VII., fig. 8, and PL VIIL, fig. 4, 1874.
,, tiiberosus, Rominger, Fossil Corals of Michigan, p. 30, PL IX., figs.

I, 2, 1876.
,, Fo?'besi (?), Hall, Twenty-eighth Ann. Rep. on the State Cabinet of

N.Y., PL IV., figs. 6-15 (not described), 1876.

Spec. Chai\ — Corallum composite, forming globular, discoidal
or clavate masses when young, and becoming when adult more
or less irregularly spheroidal, hemispherical, or pyriform in
shape, the diameter of the colony varying from less than
half an inch up to two, three, or more inches. The colony
may be attached to some foreign body by a limited portion
of its base, having the whole of the rest of its surface covered
by the calices ; or the lower surface may be covered by a con-
centrically-striated epitheca, and the calices may be confined to
the upper surface only. The corallites are prismatic, often
approximating to a cylindrical form, comparatively thick-walled,
of more or less conspicuously unequal sizes, the larger and more
cylindrical corallites having a variable number of smaller and
more angular tubes intercalated among them. The large
tubes vary from one to two lines in diameter (being some-
times less than one line), and the small tubes have a dia-
meter of from one-fiftieth of an inch to half or three-quarters
of a line. Mural pores apparently in two or three alternating
rows on each prismatic face of the corallites. Septa obsolete,
or represented by longer or shorter radiating spines arranged
in vertical rows. Tabulae, typically, complete, but sometimes
reduced to or accompanied by rudimentary horizontal laminee.

Obs. — F. Forbesi, E. and H., like F. Gothlandica, Lam., is a
comprehensive type - form, with well - marked characters, but
giving rise to a series of varietal forms, which, from one point
of view, may be regarded as distinct species. Regarded in
a broad aspect, F. Forbesi is distinguishable from F. GotJilan-
dica, Lam., and its immediate allies by the conspicuous in-

58 TABULATE CORALS.

equality of the corallites in point of size, the less markedly
prismatic and often nearly cylindrical form of the tubes, and
the greater thickness of the walls. In the observations which
I have to make upon the structural characters of F. Forbesi, I
shall take the form which occurs in the Wenlock Limestone of
Britain and Sweden as the type of the species, and I shall con-
sider the variations of this type as constituting three distinct
varieties — viz., van Wald^^onensis, Nich., Eifelensis, Nich., and
tiibcrosa, Rom. It is possible that Calamopora For best, van
discoidea, Roemer (Sil. Fauna of Tenn., p. 19, PI. II., figs. 10-
10 b), is a fourth variety ; but as I possess no examples of this
form, I am unable to offer any opinion on this point.

The normal form of F. Forbesi, E. and H,, occurs abundantly
in the Wenlock Limestone of Britain, and has been very well
illustrated by Milne- Edwards and Haime in their great work
on the British Fossil Corals (PI. LX., figs. 2- 2 g). The most
noticeable point about this form is the marked difference be-
tween young and old examples in the relative sizes of the
corallites — supposing, as I think may safely be done, that
the specimens in question really represent nothing more than
different stages of growth. Young examples (PI. II., fig. i)
are discoidal, with an inferior epitheca ; or they form globular
masses, which envelop parasitically the stem of a Crinoid or
the branch of some dendroid coral, and have their entire
free surface covered by the calices. The large-sized calices
are both exceptionally numerous and exceptionally large, their
diameter varying from a line up to close upon two lines,
while the smaller calices are usually from a quarter to half a
line in diameter, and are intercalated in comparatively scanty
numbers in the limited spaces left between the large corallites.
Transverse sections (PI. II., fig. i b) of such specimens show
precisely the same features. On the other hand, full-grown
examples have the form of hemispherical, spheroidal, or cla-
vate masses, generally two or three inches in diameter, and
the inequality of the corallites is much less marked than in
the young state (PI. I., fig. 7). There is a greater propor-

GENERA OF FA VOSITID^E. 59

tionate number of average coralli'tes ; the small tubes are fewer
in number and not so conspicuous ; and the large tubes open
on the surface by actually smaller apertures, the diameter of
the larger calices being generally about one line, but some-
times rather less. Still it would be impossible to confound
such examples with specimens of F. Gotlihnidica, since the
observer has no difficulty in at once recognising the presence
of a certain number of tubes, which catch the eye in conse-
quence of their being larger than the others ; while the pris-
matic form of the corallites so characteristic of the latter
species is never regularly developed, and the bigger calices
have a distinctly circular outline. As regards the internal
structure of this form there is little of importance to note.
The presence of septa in the form of short spines, vertical
striae, or tubercular ridges, can usually be made out by ex-
amining the surface with a lens ; and thin transverse sections
almost invariably confirm the existence of these structures (PI.
I., fig. 7, and PI. II., fig. I b). These septal spines or ridges
are, however, always short, and extend but a short distance
inwards into the visceral chamber ; nor would they usually be
recognised at all by a mere naked-eye examination of the sur-
face. Vertical sections (PI. II., fig. i a) show the tabulae to be
complete, slender, and slightly fiexuous, placed at variable dis-
tances apart, six or seven usually occupying the space of two
lines. It is specially worthy of note in this connection that
Milne-Edwards and Haime have figured an example of this
species from the Wenlock Limestone of Wenlock (Brit. Foss.
Corals, PI. LX., fig. 2/"), in which the interior of the tubes is
roughened by elevated points or ridges, which, though badly
figured, entirely correspond in appearance to the " squamae "
which we shall see to be present in F. Foi^besi, van tubei'-osa,
Rom., from the Devonian of North America, and which I
believe to be unquestionably the same in their nature.
Whether similar rudimentary tabulae are present at all com-
monly in the Upper Silurian forms of F. Forbesi, I cannot
say ; for these structures very rarely reveal themselves in thin

6o TABULATE CORALS.

vertical sections, and the British examples of this species, so
far as I have seen, very seldom exhibit the interior of the
tubes. Finally, for the reason just given, I am not certain
as to the arrangement of the mural pores in F. Forbesi ; but
in such vertical sections as show these apertures at all, they ap-
pear to be biserial or triserial, alternating in contiguous rows,
and more closely set than in F. Gotklandica (PI. II., fig. i a).

Favosites Forbesi, E. and H., var, Waldroxexsis, Nich.

(PI. II., figs. 2-2 b.)

Favosites Forbesi (1), Hall, Twenty-eighth Rep. on the State Cabinet of N.Y.,

PI. IV., figs. 6-15.

Corallum forming globular or pyriform masses (PI. II., 2),
varying from half an inch up to two inches or more In diameter,
and attached by a broad peduncle, the lower part of which may
be covered by an epitheca. Large corallites, varying from one
and a half to two lines in diameter, and proportionately very
numerous, the small corallites occupying the angular spaces
between the former, and varying from a fiftieth of an inch to
more than half a line in diameter. Septa apparently obsolete
(PI. II., 2 a). Tabulae numerous, thin, horizontal, usually about
seven in the space of two lines (PI. II., 2 b).

This well-marked form, from the Niagara Limestone of
Waldron, Indiana, quite resembles the common F. Forbesi of
the corresponding Wenlock Limestone of Europe in all essen-
tial features ; and it would be difficult or impossible to mention
any characters by which young specimens of these two forms
(up to half an inch or rather more in diameter) could be
separated from one another. The chief peculiarity of the
present variety lies in the fact that it preserves in its adult
condition the distinctions which characterise the young both of
itself and of the normal form of F. Forbesi. Hence the fully-
grown F. Forbesi, var. Waldronensis, is at once separated by
its numerous and exceptionally large corallites, and the com-
parative paucity of the small tubes, from the adult F. Forbesi
of the British Wenlock, in which the large tubes arc much

GENERA OF FAVOSITID.^. 6i

diminished in number, and there is much nearer approach to a
general equality in the size of the corallites. This distinction
will be at once evident on a comparison of transverse sections
of these two forms (PI. I., fig. 7, and PI. II., fig. 2 a).

Favosites Forbesi, var. JValdroneiisis, has been beautifully
figured by Professor Hall {loc. cit.), with a doubtful reference
to F. Forbesi, E. and H. ; but, so far as I know, no description
of it has been published. In its internal structure there is no
feature of special importance to note, save that there seem to
be no traces of septal spines, and the tabulae are perhaps more
regularly distributed and less flexuous than in the normal form
of the species. Professor Hall has figured the tubes with
biserial mural pores — and so far as I have observed, this is the
general arrangement ; but there may be an additional row, and
the pores seem to be close-set, and somewhat irregular in their
distribution.

Favosites Forbesi, E. and H., var. Eifelensis, Nich.
(PI. II., fig. 3, and PI. III., figs. I - 1 Ik)

Corallum forming spheroidal or pyriform colonies, from half
an inch up to two inches in diameter, but generally an inch or
rather more across. Corallites irregularly prismatic, or with
rounded angles, and more uniform in size than in typical forms
of the species, the larger ones being numerous, but mostly
attaining a diameter of no more than a line or three-quarters of
a line, while the small tubes are much reduced in numbers.
Septa exceptionally well developed, and extending for a con-
siderable distance into the interior of the visceral chamber, in
the form of strong blunt spines. Tabulae horizontal or slightly
flexuous, about six or seven in the space of two lines. Mural
pores numerous, close-set, apparently biserial or triserial.

I propose this name for a small Favosites which I have
found to be tolerably plentiful at Gerolstein in the Eifel. Its
general appearance (PI. HI., fig. i) is so closely similar to that
of medium-sized specimens of F. Forbesi from the Upper
Silurian, that the near relationship of the two forms is beyond

62 TABULATE CORALS.

doubt. There is also the same general disposition of the cal-
ices, there beino;- a marked difference in size between different
coralHtes. In this respect, however, the condition of matters
resembles that which obtains in lai'ge-sized colonies of the
normal F. Forbesi from the Upper Silurian. That is to say,
there is an approach to a general equality in size of the tubes,
the larger ones not being exceptionally large (mostly from
three-quarters of a line to a line in diameter), and being very
numerous as compared with the small tubes (PI. III., fig. i a).
The distinguishing peculiarity of this form, however, is the
quite unusual development of the septa, which are conspicuously
visible even to the unassisted eye, and extend a considerable
distance into the cavity of the tubes (PI. II., fig. 3). In long
sections (PI. III., fig. i b), the septa are seen to have the form
of strong spines, with a broad base, and with a distinct upward
inclination. The tabulse resemble those of the normal form of
F. Forbesi. The mural pores, as revealed by thin vertical
sections, appear to be numerous and close-set, being apparently
in two or even in three rows ; but I do not think that much
stress can be laid upon this character, especially when only
known by the, in this respect, partial and imperfect evidence
afforded by transparent longitudinal slices.

Favosites Forbesi, E. and H., var. Tuberosa, Rom.

(PI. III., figs. 2-2 ^.)

Favosites hasaltica (pars), Goldfuss, Petref. Germ., PI. XXVI., fig. 4 a (caet.
exclusis), 1829.
„ hasaltica (pars), Billings, Canad. Journ., new ser., vol. iv. p. 106,

1859.
„ Forbesi, Nicholson, Report on the Palaeontology of Ontario, p. 48,

PI. VII., fig. 8, and PI. VIII., fig. 4, 1874.
• „ iuberosus, Rominger, Fossil Corals of Michigan, p. 30, PI. IX., figs.

I and 2, 1876.

Corallum forming cylindrical or club-shaped, rarely hemi-
spherical masses, varying from an inch up to half a foot or
more in length, according to their age. Corallites conspicu-
ously unequal in size, the larger ones being somewhat cylin-

GENERA OF FAVOSITIDyE. (,^

drical, the prismatic angles of the tubes being obtusely rounded,
and varying from a line and a half to a line and three-quarters
in diameter. The small tubes are intercalated in the spaces
between the smaller ones, and are usually from a quarter to
half a line in diameter. Calices often in parts obliterated by
an epitheca. Septa represented by blunt tubercular ridges on
the inner faces of the walls of the tubes. Tabuke complete,
sometimes not developed in a perfect form, but always either
represented or accompanied by numerous close-set transverse
ridges or lamellae (" squamae "), which are to be regarded as
rudimentary tabulae, and which impart a peculiar rough aspect
to the inner surfaces of the corallltes.

This form is abundant in the Devonian deposits, and especi-
ally in the Corniferous Limestone, of Canada and the United
States, and it has a historical interest, as it is unquestionably
one of the forms figured by Goldfuss {loc. cit.) under the name
of F. basal tica. The specimen figured by Goldfuss is stated
in the text to come from Lake Erie ; and the accuracy of the
drawing places it beyond a shadow of doubt that it was a
silicified example of this form derived from the Corniferous
Limestone. Mr Billings, who clearly recognised this fact,
appropriated the name oi F. basalt ica, Goldf., for the form now
under consideration, upon the belief that the other forms
included by Goldfuss under the same title were really referable
to F. Gothlandica, Lam. I have before expressed the opinion
that we have not at present sufficient evidence to support this
course (Rep. on the Palaeontology of Ontario, p. 48). Those
forms included by Goldfuss under F. basaliica, which have
prismatic tubes and uniserial mural pores, i^nay turn out ulti-
mately to be a variety of F. Gothlandica ; but there is not at
present any definite proof of this. I preferred, therefore, and
still prefer, to retain the name of F. basaliica, Goldf. — if it is to
be retained at all — for forms which essentially belong to the
type of F. GotJilandica, but have the mural pores uniserially
arranged. The present form, on the other hand, is clearly of
the type of /^ Foi^bcsi, E. and H., with conspicuously unequal

64 TABULATE CORALS.

corallltes, and biserial or trlserial mural pores ; and the only
question, to my mind, is as to whether it should be regarded
as a variety of this, or as a distinct species. That it belongs
to the same type-foi-m cannot be questioned, and I formerly
referred it unconditionally to F. Forbesi, E. and H., which was
to all practical intents and purposes the course followed by Mr
Billings, with this difference, that he regarded F. Forbesi as
a mere synonym of F. basaltica, and therefore employed the
latter name. Having now made a careful microscopic exam-
ination by means of thin sections of both the present form and
of typical examples of F. Forbesi, E. and H., from the Upper
Silurian, I still think that the two are substantially identical ;
but the former presents so many peculiarities, that it may
reasonably stand as a distinct variety. For this I have
adopted the specific name given to it by Dr Rominger (ioc. cit.),
who describes it as a distinct species — a view for which I am
inclined to think there is as yet hardly sufficient evidence.

In general shape, the corallum of the present form only
differs from that of the typical F. Forbesi, E. and H., in the
general predominance of a cylindrical or clavate, rather than a
spheroidal figure. I have given a drawing of the youngest
and smallest specimen I have seen (PI. III., fig. 2), which gives
a very good idea of the general form of the corallum, though
adult examples may be six inches or more in length. The
characters of the corallites are, also, those distinctive of F.
Forbesi {^\. III., fig. 2 a), there being a very marked inequality
in the sizes of the tubes, and the larger ones being more or less
strikingly cylindrical, rather than strictly prismatic. The large
tubes, however, are of comparatively great size, and are com-
paratively numerous, while the small tubes are reduced pro-
portionately both in size and numbers — the condition of things
thus rather resembling what we see in the young of the typical
Upper Silurian F. Forbesi than in the adult of the same. In
calcareous examples from the Hamilton formation of Canada
(PI, III., fig. 2 b), the largest tubes are not so numerous,
while the small tubes are increased both in numbers and in

GENERA OF FA VOSITID.E. 65

size ; though I entertain no doubt as to the identity between
these and the siHcified specimens from the Corniferous Lime-
stone of the same region. As regards internal structure, the
walls of the corallites are comparatively thick, and the septa are
represented by a number (ten, twelve, or more) of blunt tuber-
cular ridges on the inner faces of the tubes (PI. III., fig. 2 c).
In silicified specimens, the tabulee generally appear to be
wanting (in their ordinary form), or are, at most, present as
incomplete transverse partitions ; but vertical sections of cal-
careous examples (PI. III., fig. 2 d) exhibit complete hori-
zontal or slightly flexuous tabulee of the ordinary type. All
the examples of this form, however, have the peculiarity that
the interior of the tubes is roughened by a series of close-
set projecting transverse ridges or lamellae, which are best
seen in silicified examples, in which the corallites are empty
(PL III., fig. 2 e), but which can be recognised in thin vertical
sections of calcareous examples as short uneven lines occupy-
ing the interspaces between the regular tabulae (PI. III., fig.
2 d). These singular and characteristic structures are clearly
represented in the specimen of this form from Lake Erie
figured by Goldfuss under the name of F. basaltica (Petref.
Germ., PI. XXVI., fig. 4 a). Mr Billings {foe. eit.), while
recognising the existence of these lamellae, regards them as
possibly merely the result of a peculiar method of fossillsation,
but I hardly think that there is any evidence to support this
view. Dr Romlnger, If I rightly understand his views, regards
these projecting lamellae (or " squamae ") as being an abnormal
form, or representative of the spiniform septa of so many of the
species of Favosites. In this view, for reasons previously given
in speaking of the genus, I cannot coincide. The transverse
position, and the often complete extension of these lamellae
across the whole diameter of a tube, are, in my opinion, fatal
to the idea that these structures are in any way of a septal
nature ; and I can only regard them as being essentially of the
nature of rudimentary tabulcE. The presence, then, of these
imperfect tabulae, is characteristic of the present form ; but I

E

66 TABULATE CORALS.

must aeain draw attention to the fact that Messrs Milne-
Edwards and Haime have figured (Brit. Foss. Cor., PI. LX.,
fig. 2 f) 2. specimen of F. Forbesi from the Upper Sihirian, in
which structures of apparently precisely the same nature seem
to be present. Upon the whole, therefore, I do not think that
the structures in question can be regarded as of specific value,
though they constitute a very striking feature in the Devonian
variety now under consideration.

Of the other characters of the present form, it Is only neces-
sary to allude to two. In the first place, the mural pores have
the character, which seems to be the general rule in the less
aberrant types of F. Forbesi, that they are usually biserial,
though sometimes triserial. They are more closely set than
in F. Gothlandica, and are stated by Dr Romlnger to be sur-
rounded by a depression instead of an elevated ring. In the
second place, many of the calices in the lower part of the coral-
lum become covered and completely sealed up by an epithecal
or opercular membrane, which can hardly be regarded as the
result of mere age, since it seems to be present in extremely
young examples (PI. III., fig. 2). It is, however, most con-
spicuous in the old specimens, in which a variable number of
the corallltes are always, or almost always, closed in this way
(PI. III., fig. 2 a), those at the summit of the colony remaining
open. It must be admitted that this peculiarity has not been
observed in any of the Silurian examples of 7^ Forbesi; but as
it occurs in several of the other species of Favosites in the same
deposits, I do not think that it can well be regarded as a
character of specific importance, being rather the result of local
conditions and of environment.

For77iation and Locality. — (i.) The typical form of F. Forbesi
— Wenlock Limestone, Longhope, Dudley, Benthall Edge, and
Stoke-Edlth ; Wenlock Limestone, Gotland.

(2.) F. Forbesi, van Waldronensis — Niagara Limestone,
Waldron, Indiana, U.S.

(3.) F. Forbesi, var. Eifelensis — Devonian (Elfler-kalk),
Gerolstein, Eifel.

GENERA OF FAVOSITIDyE.

67

(4.) F. Forbesi, van hibcrosa — Corniferous Limestone, Port
Colborne, and other localities In Ontario ; Hamilton group,
Arkona, Ontario.

Favosites (Emmonsia) hemispherica, Yandell and Shumard.
(PI. IIL, figs. 3-3/;.)

Favosites alvcolaris, Hall, Geol. of New York, p. 157, No. i-^, figs, i and

I a, 1843.
„ heiuispherica, Yandell and Shumard, Contrib. to the Geology of

Kentucky, p. 7, 1847.
Emmonsia hemispherica^ Milne - Edwards and Haime, Pol. Foss. des Terr.

Pal., p. 247, 185 1.
Favosites hemispherica, BilUngs, Canad. Journ., new ser., vol. iv. p. 107, figs.

5 7, 1859-
„ hemispherica, Nicholson, Rep. on the Palaeontology of Ontario, p.

49, PI. VIII., fig. 3, 1874.
„ Emmonsii, Rominger, Foss. Corals of Michigan, p. 26, PI. VII.,
figs. I and 2. (Non Favosites hemisphericus, Rominger, ibid.,
p. 24.)

(It has been pointed out to me by my friend Mr George Jennings Hinde,
that Mr S. A. Miller, in his * Catalogue of the American Paleozoic Fossils,' p.
52, states that this species was described by Troost in the 5th Geol. Rep. of
Tennessee, in 1840, under the name of Cahimopora hemispherica. I have not
included this reference in the above list, as I have not access to Troost's work,
and have therefore no means of verifying it. Milne-Edwards and Haime do
not include Troost in their list of references. If, however, Mr Miller's reference
be correct, then Troost's name should follow the species in place of the names
of Yandell and Shumard.)

Spec. Char. — Corallum generally hemispherical or irregularly
spherical in shape, massive, often
several inches in diameter. Coral-
lites prismatic, often with round-
ed angles, thick-walled, generally
about one line or rather less in
diameter, but varying from half a
line to a line and a quarter. Calices
subpolygonal, irregular in size and
form, with thick margins. Septa
in the form of longer or shorter
spines, but often not recognisable.
Tabulae most generally in the form of thin, Hexuous, close-set

I"''g' 15- — Fragment of Favosites hcmi-
spJierica, of the natural size. Devo-
nian (Corniferous Limestone), Ontario,
Canada. (After Billings.)

68 TABULATE CORALS.

lamince, which for the most part only extend across about a
third or a half of the total diameter of the tube. At other
times the tabulae are complete, and they are occasionally quite
regular and horizontal. Mural pores usually biserial, very
closely set, opposite or alternating.

Obs. — This species was taken by Milne-Edwards and Haime
{loc. cit.) as the type of the separate genus Emmonsia, distin-
guished from Favosites by the peculiar condition of the tabulae.
I agree, however, with Mr Billings in thinking that the occur-
rence of single examples of this species in which the tabulae are
in parts complete, renders the establishment of a distinct genus
for its reception unnecessary. Moreover, incomplete, leaf-like,
or squamose tabulae are known to occur in undoubted species
of Favosites {e.g., in F. Forbesi and in its variety tubcrosci).

Recently, Dr Rominger {loc. cit.) has applied the name of
Favosites Jiei7iisphericus, Yand. and Shum., to the entirely dif-
ferent F. turbinata of Billings ; while he has established a new
species, under the name of F. Emmonsii, for the form now
under consideration. The only ground given for this change
is, that "all the original specimens of Fav. hemisph. kept in Mr
Yandell's collection are identical with Favosites ttn^binattis of
Billines." I reofret that, after a careful consideration of the
circumstances, and with all deference to this high authority, I
am unable to acquiesce in the propriety of this change, where-
by two species thoroughly familiar to all palaeontologists are
made to change places, one of them receiving an entirely new
name. This course deprives Milne-Edwards and Haime on
the one hand, and Mr Billings on the other, of their just con-
nection with two species which they for the first time described
in an excellent and thoroughly recognisable manner; and it does
not appear to be sufficiently justified by the fact that the speci-
mens labelled F. hemisphcrica in Mr Yandell's cabinet are really
referable to F. turbinata, Billings. On the contrary, it appears
to me that the just course In such a case as this, is, not to make
any alteration in generally accepted and long current names,
unless it can be shown by clear evidence that such an altera-

GENERA OE EA VOSITID.E. 69

tlon is warranted by the published description of the original
author, since this is obviously all of which other observers can,
as a rule, avail themselves. Taking this view of the question,
I quote the entire description of the species given by Yandell
and Shumard (Contrib. to the Geol, of Kentucky, p. 7) : —

'^ Favosites hemispherica. — This fossil, the most characteristic
of the shell-beds, to which it is limited, is abundant on the Falls,
and is found in masses of a hemispherical figure, which vary
from one to ten inches in diameter. It is most commonly
calcareous, though sometimes it is siliceous."

Passing over the obvious fact that the above description —
unaccompanied by any figure — is wholly worthless as char-
acterising any species of Favosites, and that its vagueness
would have altogether justified Milne- Edwards and Haime
in giving a new specific title to the form which they were
describing, it may be simply remarked that the only two
tangible points alluded to by Yandell and Shumard are the
shape and the size of the corallum ; and in both these points
their description agrees with the Emmonsia he?7iisphei^ica of
Edwards and Haime, and differs from the description of F.
tuTbinata given by Billings. The form of F. turbinata, Bil-
lings, though not absolutely uniform, is almost always that
of a bent cone, rendering the name titrbinata a very apt
one ; while of the many examples I have seen, none could
be properly said to be " hemispherical," and none exceeds
some five or six inches in diameter. On the other hand,
Emmonsia hemisphcrica, E. and H., is typically "hemispheri-
cal" In form, and is often eight or ten inches in diameter
(Billings gives two or three feet as the maximum diameter
of specimens observed by him). Upon the whole, then, I
cannot but conclude that the names of F. hemispherica,
E. and H., and F. turbinata, Bill., ought to be retained
for the forms described by their respective authors under
these titles, and that these names should not be invalidated
by any evidence which is not based exclusively upon, or
directly supported by, published descriptions or figures of

70 TABULATE CORALS.

older date — these being, in the majority of cases, the only
data available to the worker. I have discussed this point
at some length, because it seems to me a matter of import-
ance that every observer should receive due credit for his
labour, and that the principle involved is one of some
concern to all palaeontologists and zoologists ; and I am
happy to know that in this special case I have the entire
concurrence of my friend Mr George J. Hinde, whose wide
acquaintance with the American Palaeozoic Corals generally,
and with these forms in particular, renders his opinion on
such a question of peculiar value. I need hardly add that
I do not suppose for one moment that Dr Rominger has
intentionally done an injustice to his predecessors, and I
trust that a reconsideration of all the facts of the case will
induce him to alter his decision on this point.

In its general form and habit, F. hemispkerica, Yand. and
Shum., is of the type of F. Gothlandica, Lam., its corallum being
massive, and its corallites essentially polygonal. The prismatic
shape of the tubes is, however, not so conspicuous as in the
latter species, partly because the angles of the prisms really are
often obtusely rounded, and partly because the walls of the
corallites are much thicker (PI. III., fig. 3). Without having the
obvious intermixture of large and small tubes which character-
ises F. Forbesz, E. and H,, there is a considerable want of
uniformity in the size of the corallites, and it is not unusual for
particular parts of the corallum to be occupied by tubes of less
than the average dimensions, while in other parts the average
diameter is maintained or exceeded. Upon the whole, the
majority of the corallites are from three-quarters of a line to a
line in diameter, the latter measurement being only rarely ex-
ceeded. I formerly included under this name (Joe. cii) colonies
in which the tubes have an average diameter of from half a line
to three-quarters of a line ; but I feel doubt as to whether these
really belong to this species, as I have not been able to exa-
mine their internal structure fully. Septa are present in the
form of irregular spines, which can be observed in specimens

GENERA OF FAVOSITlDyE. 71

in which the tubes are empty, or in transverse sections (PI.
III., fig. 3), but which can be with difficulty separated from
the imperfect tabulae. The mural pores are most generally
biserial, sometimes triserial, and are remarkable for their close
arrangement. In the best - preserved calcareous examples
which have come under my notice, they form a double row,
running down the centre of each prismatic face (PI. III., fig.
3 a), sometimes alternately, sometimes oppositely placed, con-
tiguous pores in each row being separated by their own
diameter or less. The most remarkable feature about the
present species, however, is presented by the tabulcs, which
can be admirably studied by means of specimens from the
Corniferous Limestone of Wainfleet, Ontario, in which the
corallum is in the exceptional condition of not only being
calcareous, but of being entirely empty and free from foreign
matter, thus quite resembling the skeleton of a recent coral.
In such specimens it is not unusual to find that the condition
of parts is twofold. In some of the tubes, sometimes in the
greater number, the corallites are traversed by horizontal and
complete tabulae, about five of which occupy the space of two
lines, the state of matters in these corallites thus resembling
what we see in F. Gothlandica, Lam. In other tubes, again,
there are few or no complete tabulae, but the visceral chamber
is crossed by a series of incomplete tabulae, in the form of thin
foliaceous, irregularly flexuous laminae (PI. III., fig. 3 <5), which
only extend to a certain distance inwards towards the axis of
the tube, and are often so closely packed as to cause a regular
interlocking of their free ends, or even an actual anastomosis
or confluence. When viewed from above, these incomplete
tabulae often have a regularly radiate arrangement, and thus
simulate septa ; but their true nature is rendered obvious by
their broad, leaf-like, or tongue-like form, and by their trans-
verse extension as regards the axis of the visceral chamber.
While many specimens, as just remarked, show a development
of complete tabulae in some tubes and of incomplete ones in
others, it should be remarked that in other examples, often of

72 TABULATE CORALS.

very large size, all the tubes exhibit the characteristic incom-
plete and inosculating tabulae of this species.

Formation and Locality. — Common in the Corniferous Lime-
stone (Devonian) of Rama's Farm, Port Colborne, and other
localities in the same formation in Ontario. The species
occurs at many points in the United States, where the
Corniferous Limestone is exposed ; and it is quoted by
Milne-Edwards and Haime from the Upper Silurian of the
same area.

Favosites Bowerbanki, Milne-Edwards and Haime, sp.
(PI. III. figs. 4-4 <^.)

Favosites spongites (pars), Lonsdale, in Murchison's Silurian System, p. 603, Fl.

XV., bis, figs. Z c-2> e (cset. exclusis), 1839.
C/mtetes (?) Bowerba?iki, Milne-Edwards and Haime, Pol. Foss. des Terr. Pal.,

p. 272, 1851.
Monticulipora (?) Bowerbanki, Milne-Edwards and Haime, Brit. Foss. Cor., p.

268, PI. LXHL, figs. I - 1 r, 1854.

Spec. Char. — Corallum exceedingly variable in form and size,
but generally in the shape of thick lobate and branched masses.
Corallites irregularly polygonal in shape, mostly about one-fif-
tieth of an inch in diameter, but sometimes less or more ; the
walls thin, and perforated by irregularly-distributed mural pores,
which vary in number in different examples, and may be uni-
serial, biserial, or triserial. Calices irregularly polygonal, occa-
sionally diamond-shaped in parts of the corallum, often divided
by incomplete vertical partitions arising from both sides of the
wall, and indicating unfinished fission of the tube. Septa en-
tirely obsolete. Tabulae very few in number, usually curved,
remote, from three-quarters of a line to a line apart.

Obs. — I have not thought it necessary to figure a specimen
of this species, as it has been very well illustrated by Milne-
Edwards and Haime (Brit. Foss. Cor., PI. LXIIL) The
principal figure given by these authors is, however, that of
a quite exceptionally complex and dendroid example of this
form. So far as I have seen, the corallum is generally in the

GENERA OF FAVOSITID.E. 73

form of lobate pyriform masses, which, when young, are from an
inch to two inches in height, with a diameter of half an inch to
an inch. Sometimes they terminate above in a simply dilated
and undivided upper surface, which may be slightly convex or
nearly flat ; but at other times they split up superiorly into two
or more lobate divisions. Older examples, with or without
proportionate increase in height, may become massive, till we
get coralla, of variable, but most generally of obconical shape,
which may be three or four inches in diameter at their summit.
While branching of the corallum is quite common, I have not
personally met with so completely dendroid a specimen as one
of those figured by Edwards and Haime (Brit. Foss. Corals,
PI. LXIIL, fig. i). The lower and outer surface of the coral-
lum does not appear to be covered with a regular epitheca — at
least I have not observed such a structure ; but the lonof irregf-
ularly prismatic corallites pass upwards from the base of at-
tachment, diverging as they go in such a manner that a side
view exhibits the walls of the corallites, broken at tolerably
regular intervals by recurrent spaces or ledges occupied by
open calices. This feature is one very characteristic of the
pyriform examples of this species, but in all forms alike the
uppermost surface is occupied by the calices.

Milne- Edwards and Haime referred this species with doubt
to ChcBtetes or Monticulipora, and of its close resemblance to
these genera there can be no question. Vertical sections, suit-
able for microscopic examination, bring into view, however, a
well-developed series of mural pores, and thus prove conclu-
sively that the species is truly referable to Favosites (PI. III.,
fig. 4 U). The pores are irregularly distributed, and seem to be
generally in two or three series, their size always being small.
They are very abundant and conspicuous in Swedish examples,
and, for some reason, appear to be much fewer in number in
British specimens, though still quite determinable with a little
care. It is worthy of note, in this connection, that though the
existence of mural pores can usually be recognised in thin
sections without any difficulty, I have never succeeded in de-

74 TABULATE CORALS.

tecting the smallest sign of these apertures by an examination
of the outsides of the tube with a hand-lens, though I have for
this purpose carefully gone over- an extensive series of excel-
lently preserved specimens. This shows that the mere fact
that mural pores cannot be detected with a magnifying-glass,
even in calcareous examples, is not proof positive that such
openings are absolutely wanting.

The corallites of F. Bozverbanki are long and slender, of
variable size, but usually from one-sixth to one-quarter of a
line in diameter. Their cross-sections (as the calices also) are
irregularly polygonal (PI. III., fig. 4), and in their general
aspect they closely resemble the corallites of Chcstetes radians,
Fischer, and its allies. They show a peculiarity, also, which is
very characteristic of the forms just alluded to (such as ChcEtetes
scptoszLS, Flem.) — viz., that the larger tubes are not uncom-
monly partially subdivided by vertical partitions, which spring
from the wall, and extend a certain distance Inwards into the
interior of the visceral chamber (PI. III., figs. 4, 4 a). These
incomplete partitions are usually placed in pairs, one opposite
the other, and they appear ultimately to become complete by
the union of their inner ends. Though they might be taken at
first sight as irregular septa, they really are not of this nature,
and they truly indicate different stages in the multiplication of
the older corallites by means of fission. Genuine septa, in the
form of vertical ridges, tubercles, or spines, such as are so com-
monly present in other species of Favosites, seem here to be
entirely absent. Lastly, the tabulae are present in the form of
slender curved plates, which are exceptionally few in number
and remote in position (PL III., fig. 4 b), not more than two or
three of these structures usually occupying the space of two
lines.

Formation and Locality. — Abundant In the Wenlock Lime-
stone of Benthall Edge, Stoke-Edith, and Longhope. Also in
the Wenlock Limestone of Gotland.

GENERA OF FA VOSITID.E. 75

Favosites clausa, Rominger.

(PI. IV., figs, I - 1 ^.)

Favosites daiisus, Rominger, Fossil Corals of Michigan, p. 36, PI. XIV., 1876.

Spec. Char. — Corallum dendroid, of branching or anastomos-
ing, cylindrical or oval stems, from two to five lines in diameter,
attached by its base, but having its whole free surface covered
by the calices. Calices open only in parts of the surface, and
especially towards the ends of the branches, but elsewhere
closed by flat or convex opercula. Corallites unequal in size,
the larger ones being conspicuously circular or oval in shape,
and about half a line in diameter, while the smaller ones are
more or less angular in form, and vary from a fifth to a third
of a line in diameter. Surface commonly marked by raised
encircling ridges, which usually have a spiral direction, and are
placed parallel with one another at intervals of from half a line
to a line or more. These are simply formed by the elevation
of the lips of a number of the calices along a given line, and they
appear to mark successive stages of growth. Septa obsolete ;
tabulae complete, horizontal, or slightly bent, from three to
four in the space of one line, sometimes with a few incomplete
tabulae interspersed among the others. Mural pores uniserial.

Obs. — This pretty little species may be regarded as a good
example of a true Favosites (as distinguished from Pachypora,
Lindst.), growing in a branching and dendroid form. The
inequality of the calices and the markedly circular shape of
the larger tubes (PI. IV., fig. i 8) are characters in which the
species makes a distinct approach to Fistulipora, M'Coy ; but
F. Fo7'besi, E. and H., exhibits the same feature to a less
marked extent ; and the presence of mural pores sufficiently
separates the present form from the species of the latter genus.
It is also separated from Pachypora by the fact that the walls of
the corallites show none of that thickening in the neighbour-
hood of their mouths which is so characteristic of the latter.
The existence of an operculum in the form of a flat or convex

76 TABULATE CORALS.

calcareous plate in a large number of the callces is a peculiar
feature in the species (PI. IV., fig. i a) ; but the same character
occurs generally in F. Forbesi, van tuberosa, Rom., and con-
stantly in F. turbinata, Bill. In all these forms the actual
characters of the operculum are the same, but in the last-
mentioned species they become more or less continuous, so as
to constitute a regular epithecal membrane, clothing the entire
under surface of the corallum. Thin tangential sections ex-
hibit no traces of septal ridges or tubercles. Similar vertical
sections show that the walls of the corallites are not thickened
as they approach the surface, and that the visceral chamber of
each tube is crossed by delicate horizontal tabulae, which are
usually complete, though occasionally incomplete ones exist as
well. Rominger says that the mural pores are " numerous."
So far as I have observed them in thin sections, they are uni-
serlal, and moderately close to one another.

Formation a7td Locality. — Hamilton Group (Devonian),
Arkona, Ontario, and Erie County, N.Y. (Dr Rominger
states that it occurs also in the Corniferous Limestone.)

77

CHAPTER IV.

GENERA OF FAVOSITID/E {coutillttcd).

Geints Pachypora, Lindstrom, 1873.
(Ofversigt af K. Vetensk. Akad. Forhandl.)

Gen. Char. — Corallum dendroid or frondescent, of polygonal
or subcylindrlcal corallites, the walls of which are greatly
thickened towards their mouths by the deposition of concentric
layers of sclerenchyma. Calices sometimes annular, some-
times oblique and semi-lunar. Septa in the form of minute
spiniform projections, or obsolete. Tabulse complete, remote.
Mural pores few in number, irregular, often of large size.

This genus was founded by Lindstrom for the reception of
the single species Pachypora lamellicornis, Lindst., from the
Upper Silurian deposits of Gotland, which will be shortly
described immediately. So far as my investigations have
gone, the genus will be found to include a considerable number
of types, some of which have been referred to Favosites, while
others have been placed in Alveolites. Thus it has been
already pointed out by Mr R. Etheridge, jun., and myself
(Journ. Linn. Soc, vol. xiii. p. 362), that the so-called Alveo-
lites Fischeri, Bill., and Alveolites frondosa, Nich., of the
Devonian deposits of North America, are really referable
to Pachypora; and I have now determined that the well-
known Favosites cristata, E. and H., of the Upper Silurian,
and F. cervicornis, De Blainv., of the Devonian, must be
placed in the same genus. It is probable, in fact, that all the

78 TABULATE CORALS.

thick-walled species which have been regarded as dendroid
forms of Favosites will more appropriately find a place in
Pachypoj^a ; and the same may be considered as likely as
regards the majority of the thick - walled types which have
been referred to Alveolites.

The mere thickening of the walls would not of itself afford a
sufficient ground for the separation of Pachypora as a generic
division, since it is present in other groups ; but there are other
distinctive characters to be taken into account as well. Little
stress can be laid upon the external form of the corallum, but
all the known species are dendroid or frondescent. P. lanielli-
corniSf Lindst, the type-species, forms flattened branches, which
are often coalescent ; P. Pischeri, Bill, and P. frondosa, Nich.,
grow as broad undulating expansions or fronds ; P. cristata, E.
and H., and P. cei'viconiis, De Blainv., are essentially ramose,
usually with cylindrical branches, but sometimes sublobate.
In all these cases the corallum is fixed to some foreign body
by its base ; and there is no epitheca, the whole of the free
surface being covered by the open mouths of the corallites.
The calices are sometimes circular, sometimes polygonal, some-
times markedly triangular ; so that the genus includes forms
which would, in this respect, fall on the one hand under Favo-
sites, and on the other hand under Alveolites. The calices are
in all instances more or less remote from one another, and
thin sections show that the cause of this remoteness is to be
found in the thickening of the walls of the corallites by a
secondary deposit of sclerenchyma. This thickening affects
the corallites throughout their entire length, but it is least
developed in the central and interior portion of the corallum,
and becomes much more conspicuous as the mouths of the
tubes are approached. Hence in tangential sections taken
close to the surface the visceral chamber is seen to be sur-
rounded by a dense calcareous envelope composed of numer-
ous delicate concentric laminae, and surrounded externally by
a clearly distinguishable proper "wall" (see PI. IV., figs. 2 a and
3 c). The tabulae are poorly developed, being few in number.

GENERA OF FAVOSITID^. 79

remote, and in general complete. P. cristata^ E. and H., how-
ever, sometimes exhibits structures which may possibly be
incomplete tabulse. Septa are usually recognisable, as minute
tubercles or spines, but may be wholly obsolete. Lastly, the
mural pores differ from those of the typical forms of Favosites
in being comparatively few in number, apparently arranged in
no regular series, and usually of large size.

From Favosites proper, Pachypora is to be distinguished
principally by the thickening of the walls of the corallites, the
characters of the mural pores and tabulse, just alluded to,
affording secondary points of difference. From Alveolites, as
I shall here define it, the genus must likewise be separated
chiefly by its incrassated walls. Striatopora, Hall, is very
nearly allied to Pachypora, but may be separated by the fact
that the cup of the calice is constricted at its base, and the
walls below this point are excessively thickened. Trachypora
E. and H., is another allied type; but in it the thickening of
the walls of the corallites attains its maximum, and tabulae are
greatly reduced or wanting.

The only other point which need be noticed is the relation
between Pachypora, Lindst., and Cladopora, Hall. The latter
genus was originally founded by Hall (Pal. N.Y., vol. ii. p.
137), for branching or reticulate corals from the Niagara
Group, " composed of a series of tubes or cells radiating
equally on all sides from the axis, and opening upon the
surface in rounded or subangular expanded mouths." The
corallites are stated to be more or less closely arranged, but
not always contiguous, and both tabulse and septa are said to
be apparently absent. On the other hand, in the latest defini-
tion of Cladopora, Hall, as given by Rominger (Foss. Cor. of
Michigan, p. 45), the genus is placed among the Favositidcs,
and is stated to possess mural pores, with " occasionally "
tabulae. There can, further, be no doubt but that the Corals
placed by Dr Rominger under this head are in great part
referable to Pachypora, Lindst. ; and as Cladopora, Hall, is of
course a much older name, it might seem proper to suppress

8o TABULATE CORALS.

the former in favour of the latter. It is not clear, however,
that any of the forms originally included by Hall {loc. cit.) under
the name Cladopora are really congeneric with PacJiypora
lamellicornis, Lindst. ; while it is certain that many of the
forms which have subsequently been placed under Cladopora
by American palaeontologists are of very diverse affinities.
Moreover, Dr Rominger states that septa are not developed in
the forms which he calls Cladopora, these structures being un-
doubtedly present in the typical forms of PacJiypora, Lindst.
Under these circumstances, therefore, I have not thought it
advisable to resuscitate the genus Cladopora, though it is quite
possible that one or more of the forms originally described
under this name by Hall are really identical in their characters
and structure with the more recently described Pachypora
of Lindstrom.

So far as certainly known, the species of Pachypora are con-
fined to the Upper Silurian and Devonian deposits.

Pachypora lamellicornis, Lindstrom.

(PI. IV., figs 2-2 f.)

Pachypora lainellicornis, Lindstrom, Nagra anteckningar om Anthozoa Tabu-
lata. Ofversigt af Kongl, Vetensk. Akad. Forhandl., 1873.
„ lajiicUicornis, Nicholson and R. Etheridge, jun., Journ. Linn. Soc,
vol. xiii. p. 361, PI. XX., figs. 15-17.

Spec. Char. — Corallum composed of broad flattened branches
having a width of from four to seven lines or more, with a
thickness of from two to three lines, often coalescing to form
flat reticulate or palmate expansions (PI. IV., fig. 2). Corallites
essentially polygonal in shape, tolerably equal in size, from one-
third of a line to two-fifths of a line or rather more in diameter.
Walls of the corallites greatly thickened by a secondary
deposit of sclerenchyma, which is laid down in delicate con-
centric laminae in the interior of the tubes, and increases
considerably in amount as the mouth is approached (PI. IV.,
figs. 2 « and 28). Calices covering the entire free surface of

GENERA OF FAVOSITID.E. 8i

the corallum, subpolygonal, rounded, or sometimes distinctly
oblique and semicircular, the margins being thick, and the
lower lip not specially prominent. Septa represented by minute
tubercles or spines, arranged in vertical rows (PI. IV., fig. 2 a).
Tabulae delicate, few in number, remote, and complete (PI. IV.,
fig. 2 b). Mural pores few, irregular, of comparatively large size.

Obs. — Dr Lindstrom has kindly furnished me with speci-
mens of this, the type-species of the genus Packypora, from
which I have been enabled to draw up the above description.
As the structure and affinities of the genus have already been
discussed at some length, it is unnecessary here to enter into
further details as to the characters of this interesting form.
In its general appearance it resembles most nearly a palmate
or dendroid Favosites; but the conspicuous thickening of the
mouths of the calices, and the consequent remoteness of these
apertures, is sufficient to separate it from the typical forms of the
latter. Sometimes the calices resemble those of Favosites in
being polygonal or rounded, sometimes they are like those of
Alveolites in being markedly oblique and semi-lunar; and both
these conditions are commonly present in the same specimen,
calices of the latter shape occurring principally towards the
ends of the branches. The lower lip of the calice is, however,
never markedly prominent, nor thinner than the rest of the cali-
cine margin. The nearest ally to P. lamellicoi'-nis is the P.
{Alveolites) Fischeri, Bill., of the Devonian of North America ;
but the corallum of the latter is invariably in the form of thin
lamellar or palmate expansions, never partially or completely
ramose, while the calices are commonly oblique and subtri-
angular over the whole surface. There is also a close resem-
blance between the present species and P. (Favosites) cristata,
E. and H., from the Upper Silurian of Britain ; but the latter
is always distinctly ramose, of more or less cylindrical branches,
while its tabulae are much more largely developed, and the
septa appear to be nearly obsolete.

Formation and Locality. — Upper Silurian (Wenlock Lime-
stone), Wisby, Gotland. {Coll. Dr Gustav Lindstrom.)

F

82 TABULATE CORALS.

Pachypora cervicornis, De Blainville, sp.

(PI. IV., figs, i-zd)

Calamopora polymorpha, var. ramoso-divarlcata, Goldfuss, Petref. Germ. t. i.
PI. XX Vn., figs. 3^, 4«, 4(5', 4^ (caet. exclusis), 1826.
„ spongites, var. j-amosa, Goldfuss, ibid., PI. XXVIII. , figs. 2a-2g

(caet. exclusis), 1826.
Alveolites cervicoriiis, De Blainville, Diet. Sci. Nat, t. Ix. p. 369, 1830.

„ reticulata, De Blainville, ibid., p. 369, 1830.
Favosites cronigera, Alveolites celleporatus, and Alveolites spongites, D'Orbigny,
Prodr. de Pale'ont, t. i. pp. 107, 108, 1850.
„ ce)i>icornis, Milne-Edwards and Haime, Pol. Foss. des Terr. Pal.,
p. 243, 185 1 ; and Brit. Foss. Cor., p. 215, PI. XLVIIL, fig. 2 (?),

1853-
„ reticulata, Milne-Edwards and Haime, Pol. Foss. des Terr. Pal.,
p. 241, and Brit. Foss. Cor., p. 215, PI. XLVIII., figs. \-\ l>,

„ polymorpha, Billings (pars), Canad. Journ., new ser., vol. iv. p. in,

fig. II, 1859. (Non Goldfuss.)
„ reticulata, Nicholson, Rep. on the Pal. of Ontario, p. 51, PI. VII.,

fig. 2, 1874.
„ dubia, Nicholson (pars), ibid., p. 51, PI. VII., fig. 5, 1874. (Non

Favosites cervicornis, Nicholson, ibid., p. 52.)
„ limitaris, Rominger(?), Foss. Cor. of Michigan, p. 35, PI. XIII.

Spec. Char. — Corallum of branching cylindricarstems, which
vary in diameter from two up to ten Hnes, and which some-
times inosculate so as to form reticulated expansions. Coral-
lites essentially polygonal, but having the visceral chamber
greatly narrowed by a secondary deposit of sclerenchyma,
which increases in amount towards the mouth, Calices sub-
polygonal, with thickened lips surrounding a subcircular aper-
ture, tolerably equal in point of size, and usually about half a
line in diameter, more or less. Septa obsolete, or represented
only by very minute spiniform tubercles. Tabulae comparatively
few in number (in some cases apparently numerous), complete,
horizontal or slightly flexuous. Mural pores few, large-sized,
irregularly distributed.

Obs. — The dendroid Favositoid Corals constitute a group
particularly difficult to study and to separate satisfactorily into
species, and with the space at my command it would be use-

GENERA OF FA VOSITID.E. 83

less to attempt to discuss and illustrate more than one or two
types. Some forms, as has been seen, have the thin walls
of Favosites proper, and are clearly generically inseparable from
the more typical massive examples of this group. The forms
now under consideration, however, have the thickened walls
and general structural characters of Pachypoj'a, Lindstrom,
under which head they ought clearly to be placed. The
species which I have here selected is one highly characteristic
of the Devonian, and I have made a careful macroscopic and
microscopic study of a large number of specimens which I have
personally collected from rocks of this age in Devonshire, in
the Eifel, and in Canada. Nevertheless I do not feel certain
as to the limits of the species, nor am I sure that all the forms
given in the foregoing list of synonyms are really only varia-
tions of a common specific type, though I am disposed at
present to take this view.

The figures which I have given (PL IV., figs. 3 - 3 <^) are all
taken from a single form, which I found to be very abundant
at Gerolstein, in the Eifel, and which I consider as certainly
identical with those figured from the same region by Goldfuss
under the name of Calamopora polyinoi'pha, var. ramoso-digitata
— these being identified by the high authority of MM. Milne-
Edwards and Haime with the Alveolites cervicornis of De
Blainville. Nor can I doubt the substantial identity of this
form with the Favosites i^etiadata of De Blainville, — the only
tangible difference between them being the unimportant feature
that the branches of the latter inosculate with one another.
On the other hand, Milne-Edwards and Haime, in the * Poly-
piers Fossiles,' state that the larger calices of F. cervicoiiiis have
a diameter of nearly two millimeters, and that the walls are
only " un peu epaisses ; " whereas they give one millimeter as
the diameter of the calices in F. retiailata, and speak more
decisively as to the thickness of the walls of its corallites.
Goldfuss's figures, however, which are usually very reliable,
show hardly any appreciable difference in the size of the coral-
lites in these two forms, both having the majority of the calices

84 TABULATE CORALS.

about one millimeter in diameter, and thus agreeing with the
examples which I have seen from the Eifel. The statements
on this head made by Milne-Edwards and Haime would much
more closely apply to the form which they have described and
figured from the Devonian rocks of Devonshire under the
name of F. ccrviconiis (Brit. Foss. Cor., PI. XLVIII., fig. 2),
and which is so common in the limestones of Newton-Bushell
and Torquay. This form has large calices which are often
nearly two millimeters in diameter, and the thickening of its
walls (though present) is not strikingly marked. I am, how-
ever, very much disposed to doubt if this be specifically iden-
tical with the form figured by Goldfuss from the Eifel, and
my opinion is based both upon actual specimens and upon
thin sections. The Devonshire form is rather sublobate than
strictly dendroid ; its walls are not nearly so thick as those of
the typical examples from the Eifel ; its calices are on an aver-
age larger ; and its tabulae are much more numerous and more
closely set. Upon these grounds, though I have doubtfully
placed it under this species, I am inclined to think that it is
entitled to at least varietal if not specific distinction. The form
figured by Billings, from the Corniferous Limestone of Canada,
as F. ccrvicoruis (Canad. Journ., new sen, vol. iv. p. no, fig.
9), and subsequently described by me under the same name
(Rep. on the Pal. of Ontario, p. 52, 1874), is apparently identi-
cal with, or closely allied to, the Devonshire form, and differs
from the Eifel specimens in the characters above alluded to as
distinctive of the British examples.

Favosites polymorpka, Goldfuss, has often been regarded as
comprising dendroid forms, probably in part identical with the
present type. It seems clear, however, that this name, if it be
retained at all, can only be with propriety kept for examples of
a submassive or completely massive form, with uniserial pores,
and with the thin walls characteristic of Favosites proper.

Favosites dubia, De Blainv., again, comprises dendroid species
which are obviously of the Pachypora type, and it is a question
whether the species can be maintained as distinct from Pachy-

GENERA OF FAVOSITIDM. 85

pora [Favosiics) cervicornis. The presence of very minute
calices scattered among the larger ones is of itself, perhaps,
hardly of more than varietal value ; but if Goldfuss's figure can
be trusted {Calamopoi'a polyinorpha,v2.x. gracilis, Petref. Germ.,
PI. XXVII., fig. 5), then PachypoTa {Favositcs) dubia is suffi-
ciently distinguished from P. cervicornis by the comparatively
large size and the obliquity of its calices.

Lastly, it seems very probable that some of the forms figured
by Rominger (Fossil Corals of Michigan) are really inseparable
from the present species ; and this is specially the case with F.
limitaris, Rom., in part or in whole. From an examination of
numerous specimens of this form from the Corniferous Lime-
stone of Ontario, I can assert its very close resemblance to ex-
amples of P. cervicornis from the Eifel — this resemblance in
some cases amounting to absolute identity of external char-
acters. Other specimens, again, have larger and more dis-
tinctly circular or annular calices, thus closely approximating to
the type of Pachypora {Favositcs) dubia, De Blainv. Unfortu-
nately, the highly silicified state of the Canadian specimens,
accompanied with a more or less completely hollow condition
of the tubes of the corallites, renders it impossible to prepare
satisfactory microscopic sections ; and in the absence of these,
I hesitate to pronounce as to their absolute identity with
the European type, though I cannot doubt their very close
alliance.

Taking the Eifel specimens as the type of Pachypora cervi-
cornis, De Blainv., the corallum is generally in the form of cy-
lindrical or subcylindrical, often irregularly swollen branches,
from two to ten lines in diameter (PI. IV., fig. 3), dividing at
variable intervals, but usually not anastomosing. Where inos-
culation of the branches occurs, it may perhaps be convenient
to use De Blainville's name of reticulata as a varietal designa-
tion, though forms so characterised certainly differ in no other
particular from those which divide without anastomosis. The
corallites radiate from the axis of the branch, curving gently
outwards till they open on the surface, and their true form is

86 TABULATE CORALS.

essentially polygonal. This is clearly shown by sections at
right angles to their course, and especially by those which
cut perpendicularly across their axial portions (PL IV., fig. 3 c).
The walls of the corallites, under all circumstances, remain quite
distinctly recognisable in thin sections, but the visceral chamber
becomes more and more contracted as we approach the mouths
of the tubes, by a dense secondary deposit of sclerenchyma (PI.
IV., figs. 3 <5, 3 c). As the result of this thickening of the
walls, the calices assume the form of rounded apertures encircled
by a prominent thickened margin (PI. IV., fig. 3 a), the true
wall being still discernible as a raised thread-like line describ-
ing a polygon round the central opening. In transverse or
tangential sections (PI. IV., figs. '^ b, -^ c), the visceral chamber
is seen to be reduced to a comparatively small circular or oval
tube; and in longitudinal sections (PI. IV., fig. 3 d) the same
feature is shown, while it is seen that the secondary deposit of
sclerenchyma is laid down irregularly, so as to constrict the
visceral chamber unequally at different points, but always most
markedly towards the mouth. Vertical sections also show that
the tubes are crossed by a few comparatively remote, complete,
and approximately horizontal tabulae, and that the walls are
pierced by a few larged-sized and irregularly placed mural
pores. In many instances, transverse or tangential sections
coincide in places with the plane of a mural pore, and then
the visceral chambers of contiguous corallites are shown as
laterally continuous (PL IV., fig. 3 d). Septa are sometimes
not recognisable at all ; but in other instances their presence
can be detected in the form of very rudimentary spiniform or
tubercular projections into the interior of the visceral chamber.
One of the nearest allies of the form here selected as the
type of Pachypora ccrvicornis, De Blainv., is the P. (Favosites)
crisiaia, E. and H., of the Upper Silurian. The latter, how-
ever, is distinguished by the constant presence of minute calices
interspersed among the larger annular apertures, by the smaller
size of average examples of the corallum, and by the possession
of more numerous tabulae, while the septa are often long and

GENERA OF FAVOSITID^. 87

spinlform, and the mural pores are much smaller, (The only
variety of P. cervicoiniis in which I have observed comparatively
numerous tabulae is that from the Devonian rocks of Devon-
shire, and I have already given reasons for thinking this to be
probably at least varictally distinct from the Eifel form, if not
a good species.)

Formation and Locality. — Abundant in the Devonian Lime-
stone of Gerolstein in the Eifel. Also not uncommon in the
Corniferous Limestone of Wainfleet, Ontario. [Quoted by
Milne- Edwards and Haime as occurring in the Devonian of
France, Belgium, Germany, Spain, Turkey in Europe, and
Britain.]

Pachypora cristata, Edwards and Haime, sp.

(PI. IV., figs. 4-4/^, and PI. V., figs, i-i ^.)

(?) Aladreporites crts/atus, Blumenbach, Comment. Soc. Scient. Gott., t. xv.

p. 154, PI. III., fig. 12, 1803.
Favosites po/ymorJ>/ia, Lonsdale, in Murchison's Silurian Syst., p. 684, PI.
XV., fig. 2, 1839.
„ Lonsdalei, D'Orbigny, Prodr. de Pale'ont., t. i. p. 49, 1850.
„ cristata, Milne-Edwards and Haime, Pol. Foss. des Terr. Pal., p.
342, 185 1 ; and Brit. Foss. Cor., p. 260, PI. LXL, figs. 3 and 4,
1854.
Calainopora cristata, Fr. Schmidt, Sil. Form, von Ehstland, p. 239, 1858.
„ cristata, Ferd. Roemer, Sil. Fauna des West. Tennessee, p. 20, PI.

II., fig. 12, i860.
Favosites Lonsdalei, Lindstrom, Ofversigt af Kongl. Vetensk. Akad. Forhandl.,
1873, p. 22.

Spec. C//^;'.—Corallum dendroid, or sometimes sublobate; the
branches generally cylindrical, often irregularly swollen, from two
to four or five lines in diameter, dividing at frequent intervals,
and terminating;' in rounded ends. Corallites radiatinof from
the axis of the corallum, and diverging outwards to open on
all parts of the free surface ; their walls thickened by scler-
enchyma, especially in the neighbourhood of their mouths.
Mural pores few in number, apparently uniserial or irregular.
Calices rounded, encircled by greatly thickened margins, and
usually of two principal sizes, — the larger ones often nearly or

88 TABULATE CORALS.

quite circular, and from half to two-thirds of a line in diameter;
while the smaller ones are intercalated among the preceding,
are often subpolygonal or angular, and vary from a quarter to
a third of a line in diameter. Septa represented by radiately
arranged spinules, or nearly obsolete. Tabulae numerous,
complete, usually curved with their convexity downwards,
or flexuous.

Obs. — The present species was identified by Milne-Edwards
and Haime with the Madreporites ci'istatus of Blumenbach ; and
if this identification be correct, it ought to stand as Pachypora
cristata, Blum, sp, Lindstrom has, however, expressed the
opinion {loc. jam ciL), that the form described under the above
title by Blumenbach was really the Devonian P. [Favosites)
cervicornis, De Blainv., and he therefore revives for the form
now under consideration D'Orbigny's name of F. Lonsdalei.
Not having it in my power to decide whether or not the iden-
tification of Milne-Edwards and Haime is well founded, I have
preferred to keep the species in the meanwhile under the name
by which all British palaeontologists know it, and by which it is
described in the two classical treatises of the French authors.

Pachypora crista fa, E. and H., usually presents itself in the
form of small branching fragments, which may be cylindrical,
or which may be so far dilated as to be almost sublobate. I
have never seen any fragments even as large as those figured
by Edwards and Haime (Brit. Foss. Cor., PI. LXL, figs. 3, 4),
and I should imagine the perfect corallum to have attained no
great size. The diameter of the branches is most commonly
from two to four lines ; and an examination of its internal struc-
ture at once shows it to belong to Pachypora, Lindst, and not
to Favosites proper. Transverse sections (PI. V., fig. i) show
that the corallites are essentially polygonal, and that their pro-
per walls are distinctly recognisable ; but the interior of the
tubes is narrowed by a dense deposit of sclerenchyma, which
increases in quantity as the aperture is approached, and which
leaves only a small oval or circular central space. Longitudinal
sections (PI. V., figs, i a and i b) show precisely the same fea-

GENERA OF FA VOSITID.E. 89

tures. The calices also (PI IV., figs. \a and 4 b) exhibit the
thickened Hps so characteristic of Pachypora, the proper wall
being still marked by a raised line which forms the crest of the
calicine margin. The characters of the calices differ to a con-
siderable extent in two different groups of examples. In one
of these groups — which at the same time comprises the smaller
forms, with the most regularly cylindrical branches — the calices
(PI. IV., figs. 4 and 4 a) are markedly circular or annular, open-
ing flush with the surface, and havinor a diameter for the most
part of about half a line. Mixed up with these larger calices
are smaller ones, which are also more or less circular, and vary
from a quarter to a third of a line in diameter. On the other
hand, in another great group of specimens — in which the cor-
allum is usually irregularly swollen, or even sublobate — the
calices (PI. IV., fig. 4 b) are more disproportioned in their
dimensions, the larger ones being from two-thirds to even
three-fourths of a line in diameter, while the small ones are
wedged in among the bigger openings, and are mostly poly-
gonal or angular. The large calices, also, are not always mark-
edly circular, but are often oval, and they have a decided ob-
liquity to the surface, which varies in amount in different speci-
mens. (I have never seen any example with an obliquity so
great as that figured by Milne-Edwards and Haime, Brit.
Foss. Cor., PI. LXI., fig. 4 a, where the front wall of each
corallite is free and exposed for a considerable distance ; but
I have seen an approach to this condition. Possibly this was
a weathered specimen.) Marked examples of these two condi-
tions may easily be selected, which are so different in appear-
ance that they might quite well be regarded as distinct species.
After an examination, however, of a large number of specimens,
I find the two groups to shade into one another so impercep-
tibly, that I cannot regard them as specifically separable. I
agree, therefore, with Milne-Edwards and Haime, who recog-
nised the two conditions of the species to which I have just
referred, and who regarded the smaller form, with the rounded
calices, as the type of the species ; while they figured the form

90 TABULATE CORALS.

with the larger and more obHque cahces under the name of
varietas major (Brit. Foss. Cor., PI. LXI., fig. 4 a). I thus
regret to find myself unable to adopt the opinion of my friend
Dr Lindstrom on this point, who regards the latter form (viz.,
van majoi') as the type of P. cristata, while he considers the
examples with the annular calices as specifically distinct.

In a few instances, I have noticed the existence of an oper-
culum closing the mouth of a tube, but this seems to be un-
usual. The condition of the septa varies. In some examples
they cannot be recognised at all, whereas in others (certainly
not so commonly) the mouths of the corallites are seen to
be clearly marked by radiating ridges. Thin transverse and
tangential sections (PI. V., fig. i) show the same differences.
Usually such sections exhibit no traces of septa, or only a few
rudimentary tubercles, but sometimes there proceed tolerably
long spines into the interior of the tube. Similar spines are
present in most longitudinal sections, but in very varying num-
bers. Sometimes (PI. V., fig. i a) there are very i&\N of them ;
but in other instances (PI. V., fig. i b) there are numerous
pointed spines which spring from the walls, and are directed
upwards into the visceral chamber. It seems almost certain
that these spines are truly septa, though some of them may
perhaps be of the nature of incomplete tabulae. The tabulse
are well developed, about five or six in the space of two lines,
complete, usually curved, with their convexities turned towards
the base of the corallum, sometimes irregularly flexuous. I
have only been able to investigate the mural pores by means
of thin vertical sections, in which these openings may be often
partially detected. They are of no great size, and appear to
be either uniserial or irregular.

P. C7'istata, E. and H., is distinguished from P. lamellicornis,
Lindst, by the different form of the corallum, the presence of
small calices interspersed among the larger ones, and the much
greater development of the tabulse. From the P. cervicornis,
De Blainv., of the Devonian, the present species is separated
by slight but upon the whole readily recognisable differences

GENERA OF FA VOSITID.E. 91

in external appearance : while its calices are more conspic-
uously annular, and more obviously of two sizes, its tabulee
are more numerous (as compared with typical examples of
the former), and its mural pores are markedly smaller and
apparently more numerous.

Formation and Locality. — Common in the Wenlock Lime-
stone of Benthall Edge, and Dormington Quarry, near Stoke-
Edith. (Milne - Edwards and Haime and Lindstrom quote
it from a corresponding horizon in Gotland. It is also very
probable that some of the so-called CladoporcB of the Niag-
ara and Lower Helderberg groups of North America really
belong to this species ; but there are at present no means of
verifying this conjecture.)

Pachypora Fischeri, Billings.

(Fig. 16.)

Alveolites Fischeri, Billings, Canad. Journ., new sen, vol. v. p. 256, fig. 6,
i860.
„ Fischeri, Nicholson, Report on the Palaeontology of Ontario, 1874,

P- 57-
Cladopora Fischeri, Rominger, Foss, Cor. of Michigan, p. 47., PL XIX., figs.

I and 4, 1876.
Pachypora Fischeri, Nicholson and R. Etheridge, jun., Journ. Linn. Soc, vol.
xiii. p. 362, Pi. XX., figs. 18-20, 1877.

Spec. Char. — Corallum forming flattened expansions or
fronds, of a palmate form, and from one to four lines in
thickness, and often of considerable size. Corallites disposed
obliquely to the surfaces, diverging in opposite directions from
a central plane, and opening by distinct calices over the whole
free surface of the corallum on both sides of the frond.
The corallites are subpolygonal in shape, but their interior
is thickened by a secondary deposit of sclerenchyma, arranged
in concentric laminae, so as to leave only a comparatively small
oval or circular central tube. Calices sometimes rounded or
oval, sometimes markedly oblique and subtriangular — both
conditions sometimes prevailing in different parts of the same
specimen. About three, or sometimes four, calices in the

92 TABULATE CORALS.

space of two lines, measured transversely as regards the axis
of the frond. Calicine margins much thickened. Septa ob-
solete ; tabulae few, remote, and complete. Mural pores few,
large-sized, irregularly distributed.

Obs. — The above diagnosis gives all the principal characters
of this species. Originally described by Mr Billings, and
subsequently by myself, as an Alveolites, it was referred by Dr
Rominger to Hall's genus Cladopora. I have, however, already
given my reasons for thinking that this generic name cannot
be advantageously retained ; and the present form, at any rate,
differs from those to which Professor Hall originally gave this
title, in the possession of well-developed tabulae. At a still later
date it was referred by Mr R. Etheridge, jun., and myself to
Pachypoi'ay Lindst. ; and its very close alliance with P. lamellicor-
7iis, Lindst, renders the propriety of this reference undeniable.
The specific differences between these two forms are, however,
numerous ; and though it possesses the internal structure of
Pachypora, the present form in external characters very nearly
approaches Alveolites, Lam., and thus forms a connecting-link
between these two generic types. The corallum in P. Fischeri^
Bill. (fig. 1 6, a), is a palmate, flattened, and undulated ex-
pansion, which doubtless attained considerable dimensions
though the larger examples (three inches or more in length)
are always broken ; while the thickness varies from one to three
or four lines. At its base, the corallum was fixed to some
foreign body, but its entire free surface is occupied by the
calices, the corallites diverging regularly from an imaginary
plane midway between the two flat surfaces of the frond
(fig. 1 6, b). The corallites thus open obliquely on the surface,
but the apparent obliquity of the calices varies greatly. In
some examples (fig. i6, c) the calices are very slightly oblique,
oval or circular, and in these there are about three calices in
the space of two lines, in whatever direction the measurement
be taken as regards the frond. In other cases (fig. i6, d) the
calices are oblique, oval, or subtriangular, or lozenge-shaped,
sometimes with the thin lower lip characteristic of Alveolites,

GENERA OF FA VOSITFD^.

93

and in these there are generally four caHces in the space of
two lines measured across the frond, and five of these apertures
on the same space measured vertically. These differences,

_^^ mi

l6.— A, A young but imperfect specimen of Pachypora J^isc/u-ii, Bill., from the Hamilton
group of Ontario, of the natural size, showing the general form and characters of the
coralluni ; B, Vertical section of the corallum, at right angles to its flat surfaces, enlarged
three times, showing the divergence of the corallites from a central plane ; c. Portion of
the surface of a specimen with rounded calices, enlarged five times ; D, Portion of the
surface of a specimen with oblique calices, enlarged five times ; e. Tangential section of
a specimen with oblique calices, enlarged six times ; F, Tangential section of a specimen
with rounded calices, enlarged six times ; G, Vertical section of a specimen with oblique
calices, parallel with its flat surfaces, enlarged six times, showing tabulce and mural pores.

however, are not of specific value, since intermediate conditions
are common, and different parts of the same specimen may
exhibit both of these states. In both cases, also, thin sections
taken in a plane tangential to the surface and just below it,
show that the walls of the calices have the characteristic
thickening o{ Pachypora (fig. i6, e and f), this being due to the

94 TABULATE CORALS.

deposition of delicate concentric laminae of sclerenchyma within
the interior of the corallites. The same thickening is shown
by the comparative remoteness of the openings of the calices
on the surface ; but this feature is much more conspicuous in
specimens in which the calices are rounded than in those in
which they are oblique and more closely crowded together.
Sections taken along the median plane of the frond (fig. i6, g),
and cutting the tubes longitudinally, also exhibit much-thick-
ened walls and correspondingly contracted visceral chambers.
Sections of this kind further show that complete and delicate
tabulae are always present, though few in number, and placed
wide apart, while the mural pores are few in number, large in
size, and quite irregular in position. Lastly, there are no traces
of septa to be detected, even in a rudimentary form, either in
tangential or in longitudinal sections.

Formation and Locality. — Common in the Hamilton for-
mation (Devonian) of Arkona, Ontario ; also, rarely, in the
Corniferous Limestone (Devonian) of Port Colborne, Ontario.

Pachypora frondosa, Nicholson.

(Fig. 17.)

Alveolites frondosa., Nicholson, Geol. Mag., new ser., Dec. II., vol. i. p. 15,
PI. II., fig. 2, 1874 ; and Rep. on the Palaeontology of Ontario,

1874, P- 57-
Paehypora frondosa, Nicholson and Etheridge, jun., Journ. Linn. Soc, vol.

xiii. p. 362, 1877.
Cladopora Canadensis, Rominger, Foss. Cor. of Michigan, p. 48, PI. XIX.,

fig- 3. 1^77-

Spec. Char. — Corallum forming elongated palmate flattened
expansions, which grew in an erect position from a rooted base,
and which have their entire free surfaces covered with the open
mouths of the corallites. In size, the corallum is usually from
half an inch to an inch and a half in width, with a height of
two inches or more, and a thickness of generally two lines or
less. The corallites diverge from an imaginary plane midway
between the two flat surfaces of the expansion, and open ob-

GENERA OF FAVOSITID.E.

95

liquely on the surface. Walls thickened, and completely amal-
gamated in contiguous tubes. Calices subtriangular, oval, semi-
lunar, or sometimes fissure-like, with thickened margins, but
generally with a sharp lower lip which may be indented with
one or more emarginations. The arrangement of the calices
is very irregular, but they are often disposed in diagonal lines
running across the frond, and there are usually five or six of
them in the space of two lines. One or two inward projections
of the wall of the corallites on one side may represent septa ;
or these structures may be wholly wanting. Tabulae obsolete,
or few, remote, and complete. Mural pores apparently very
few and remote.

Obs. — In its general habit and form this species (fig. 17)
closely resembles P. Fischer i, Bill., both constituting thin flat-

Fig. 17. — A, A fragment of FacJiypora frondosa, Nich., of the natural size, shown as if
attached to some foreign body, and with the extremities of the frond restored in outline ;
B, A small portion of the surface of the same, enlarged five times ; c, Tangential section
of the same, enlarged seven times; D, Vertical section of the same, similarly enlarged ;
E, Section at right angles to the flat surfaces of the frond, enlarged twice, showing the
divergence of the corallites from a central plane, together with a few tabulae. From the
Hamilton group of Arkona.

tened fronds, attached basally to some foreign object, and hav-
ing the corallites so arranged in reference to the median plane
of the expansion as to open over the whole of both of the flat

96 TABULATE CORALS.

surfaces as well as on the edges of the corallum. In spite,
however, of this close general resemblance, I do not yet feel
absolutely satisfied that the present species is rightly referred
to the genus Pachypora, Lindst. ; and it will require more ex-
tended investigations than I have hitherto been able to carry
out before this point can be finally settled. In fact, P.frondosa
exhibits a union of the features which characterise Pachypo7'a
proper with those distinctive of Cceiiites, and I am not sure
that it will not be ultimately necessary to remove it to the
latter genus. This point is especially shown by the calices.
These openings, though never actually rounded or polygonal,
are often oval, and they are seen in sections parallel with the
surface (fig. 17, c) to be surrounded by a dense deposit of
sclerenchyma, as in Pachypora. On the other hand, the calices
are commonly subtriangular, and in parts of the frond they are
generally quite crescentic or even fissure-like, while the lower
lip is sharp and thin, and may project inwards as a single or
double tooth, as in Camites. Moreover, though the walls of
the corallites are thickened, and the calices thus rendered re-
mote, I have failed to detect the delicate concentric laminee of
sclerenchyma so characteristic of Pachypora ; and the walls of
contiguous tubes are completely incorporated, and exhibit no
clear line indicating their original separateness. The com-
paratively numerous septal spines of P. lamellicornis, Lindst,
are here wanting, but one or two ridges on the interior of one
of the walls of the corallites may represent septa. In other
cases, however, the tubes appear in transverse section (fig.
1 7, c) to be oval or rounded, and there may be no traces of
septal ridges or tubercles. Thin sections taken along the
median plane of the expansion, and cutting the tubes longi-
tudinally (fig. 1 7, d), show no signs of tabulae, or but unsatis-
factory ones ; but sections taken at right angles to the flat
surfaces of the frond (fig. 1 7, e) show that these structures are
at any rate occasionally present, when they are few, remote, and
complete. I have not been able to discover mural pores other-
wise than by the presence of lateral communications between

GENERA OE EA VOSITID.E. 97

the visceral chambers of contiguous tubes, as seen in long sec-
tions (fig. 17, d) ; and the presence of a few remote and large-
sized pores may be regarded as thus sufficiently established.
Taking all its known characters into consideration, I am dis-
posed to regard the present species as congeneric with P.
Fischeri, Bill., though with affinities to Coenites.

There cannot be any question as to the identity of P.
froitdosa, Nich., with the form more recently described by Dr
Rominger from the Devonian rocks of North America under
the name of Cladopora Canadensis {loc. ciL) I have also a
number of specimens from the Devonian limestones of the
Eifel, which appear to be undistinguishable from P. frojidosa ;
but as my collections from this region are as yet imperfectly
examined, I shall leave this point open in the meanwhile.

Formation and Locality. — Common in the Hamilton forma-
tion (Devonian) at Arkona, Ontario.

Germs Striatopora, Hall, 1852.
(Pal. N. York, vol. ii. p. 156.)

Gen. Char. — Corallum dendroid, of simply-dividing cylin-
drical stems. Corallites essentially polygonal, diverging from
an imaginary central axis, their walls greatly thickened by a
secondary deposit of sclerenchyma, which increases in amount
as their mouths are approached. Calices in the form of cir-
cular apertures surrounded by a cup-shaped thickened margin,
the floor of which is striated by rudimentary septal ridges.
Septal spines in vertical rows occasionally present. Tabulae
few, remote, complete. Mural pores comparatively numerous,
circular, irregularly distributed.

Obs. — The first species of this genus which was described or
figured is the Striatopora lowensis of Dale Owen {^S. rugosa^
Hall), of which its author gave a brief description under the
name of CyatJwpora lowensis (Rep. Geol. Expl. Iowa, Wis-
consin, and Illinois, p. 69, 1844). It is not necessary here to

G

98 TABULATE CORALS.

enter into the discussion raised by Meek and Worthen (Geol.
Survey of Illinois, vol. HI. p. 368, 1868), as to whether Dr Dale
Owen is entitled to priority, In the sense that Hall's name of

Striatopora should give way to
Cyathop07'a. There is no doubt
at all that Cyathopora lozvensis,
Dale Owen, is a genuine Stria-
topo7'a ; but the fact that Dr Owen
gave no separate description of

Fig. 18.— Fragment o( SM\7/o/>ora flexu- the geUUS CyatJlOpOVa, COUpled wltll
(?j(7, Hall, of the natural size. Niagara , ■, .... - , .

formation. After Hall. ^lie close Similarity oi tliis name

to the entirely different Cyatho-
pora of MIchelln, would render It highly undesirable to
supplant the well -recognised title of Striatopora, even if
It were demonstrable that strict justice would require this
change.

The genus Striatopora was very briefly defined by Hall
{loc. cit.), and Its zoological relations are left undecided ; but
Dr Rominger (Foss. Cor. of Michigan, p. 57) has correctly seized
its true affinities, and has placed it In the family of the Favo-
sitidcB, a position to which I had independently and simulta-
neously assigned it (Art. *' Corals," Encyclopaedia Brit., 9th ed.,
vol. vl. p. 377). Microscopic examination, in fact, by means
of thin sections, places it beyond a doubt that Striatopora^
Hall, is an immediate relative of Favosites Itself, and that It
agrees so closely with Pachypora, Lindst., that the two may
be safely regarded as mere offshoots of a common stem. All
the known species of Striatopora possess a ramose corallum,
composed of cylindrical stems, which divide in a dichotomous
manner, but are not known to Inosculate. The corallltes
diverge In an obliquely-curved manner from a central axial
line, and open by large irregularly-sized polygonal callces on
all parts of the free surface. The general form and structure
of the corallum are thus precisely those of any dendroid species
oi Favosites ; and the close relationship of the two genera is
shown by the existence In Striatopora of numerous circular mural

GENERA OF FAVOSITID^. 99

pores, of well-developed though sparse tabulae, and, sometimes
at any rate, of spiniform septa. On the other hand, the corallites
exhibit, in an even more extreme degree, the thickening of
their walls by a secondary concentrically-laminated deposit of
sclerenchyma, which is so characteristic of Pachypora, Lindst.
There is, indeed, no feature in the way of internal construc-
tion which could be brought forward as separating Striatopora
from Pachypora ; and in distinguishing these two types we
have to fall back upon a well-marked external character. In
all the forms of Pachypora, Lindst., namely, the actual orifices
of the corallites are but slightly sunk beneath the general sur-
face, and they are surrounded by thick and but faintly-crested
margins. On the other hand, in all the species of Striatopo7^a,
Hall, the circular apertures of the corallites are more or less
deeply sunk below the general surface, and open at the bottom
of an expanded polygonal cup (fig. 18), the actual margins of
which are as thin as the lips of the calices in a species of
Favosites. This feature is quite sufficient to distinguish Striato-
pora from either Favosites or Pachypora, between which it is in
this respect an intermediate link ; though it must be admitted
that the filling up of the cup-like terminations of the corallites
by the matrix to the level of their free margins, sometimes
renders it difficult to apply this distinction in practice. More-
over, the floor of the cup-shaped calices of Striatopora is seen
in perfect specimens to be generally striated in a radiating
manner, with delicate ridges or rows of tubercles, representing
septa (fig. 18) ; though this character also cannot be constantly
recognised, and is present in a minor degree in some forms of
Pachypora (e.g., P. cristata, E. and H.)

The geological range of Striatopora, so far as known, is a
limited one, all the described species being either Upper Silu-
rian or Devonian in age. I have made a careful microscopic
examination of S. Linncana, Bill, from the Hamilton group
of Ontario, and also of 6". HalH, Lindst., from the Wenlock
Limestone of Gotland, but I shall merely give a brief descrip-
tion of the former of these. So far as I am aware, the genus

loo TABULATE CORALS.

has not yet been recognised as British, though it will doubt-
less yet be found to be represented in our area.

Striatopora Linneana, Billings.

(PL v., figs. 2-2 ^.)

Siriatopom LJnneana, Billings, Canad. Journ., new sen, vol. v. p. 253,
fig. I, i860.
,, Linneana, Nicholson, Rep. on the Paleontology of Ontario, 1874,

P- 59-
„ Linneana, Rominger, Foss. Cor. of Michigan, p. 59, PI. XXIII.,

figs. 5 and 6, 1877.

Spec. Char. — Corallum dendroid, of dichotomously-branched
cylindrical stems, which have a diameter of from two to five
lines. Corallites polygonal, diverging from the central line of
the branches in gentle curves to open on all points of the free
surface, their walls greatly thickened by the growth of a de-
posit of sclerenchyma, which increases in amount towards their
expanded mouths. Calices of very unequal dimensions, the
larger ones mostly about one line in diameter, the younger
ones of all sizes, intercalated uniformly among those of full
growth. The margins of the calices are polygonal and thin,
and surround a funnel-shaped or cup -shaped cavity which
opens below by a contracted circular orifice into the proper
tube-cavity. The thickened neck of the tube exhibits radiating
septal ridges or spines, which are continued throughout the
length of the tube, but the outer cup appears to be smooth.
Tabulae few, remote, complete. Mural pores moderately nu-
merous, irregularly distributed.

Obs. — There is little need to add any remarks to the above
description, all the essential characters of the species being
further shown in Plate V., figs. 2- 2 d. All the specimens I
have seen are fragmentary, and are in the form of cylindrical
or slightly-compressed stems (PI. V., fig. 2), which evidently
subdivide only at considerable intervals, as often no branch can
be observed. When not filled up with adherent matrix, the
calices (PI. V., fig. 2 a) at once show the characters of Striata-

GENERA OF FAVOSITID.E. loi

pora^ being in the form of deep cups, surrounded by thin poly-
gonal margins, with a much smaller rounded or oval aperture
at the bottom, leadins: into the visceral chamber. Tancjential
sections taken close below the surface (PI. V., fig. 2 c) show
that the throat of the tube is beset with a variable number of
radiating spines, representing the septa ; and similar structures
may often be detected within the tube-cavity itself Transverse
sections (PI. V., 2 b) show (like the preceding) that the walls
of the corallites are immensely thickened by numerous delicate
concentric laminae of sclerenchyma deposited In their interior ;
and they are specially instructive as exhibiting the varia-
tion of the amount of this secondary deposit In different
parts of the corallites. Thus, in the centre of such a section
the vertically - placed tubes in the axis of the branch are
cut across at right angles, and here their diameter is com-
paratively small, and the extent to which they are filled up is
less. On the contrary, the outer portion of such a section cuts
obliquely through the corallites in the terminal part of their
course, just as they curve outwards to open on the surface. At
this point, therefore, the tubes are seen to be considerably ex-
panded, and a proportionately large amount — generally about
two-thirds — of the actual space comprised within the proper
walls of the corallites is here filled up with sclerenchyma.
Vertical sections (PI. V., fig. 2 d) show the general course of the
tubes, and also the same progressive thickening of the walls
as the mouth is approached. They show at the same time
that the proper walls of the corallites never become obliterated ;
that the visceral chamber is crossed by remote, delicate, hori-
zontal, and complete tabulae ; and that contiguous tubes are
placed in communication by comparatively abundant circular
mural pores, which in all respects appear to resemble those
of Favosites itself, except that they appear to have a quite
irregular distribution.

Formation and Locality. — Rare in the Hamilton group
(Devonian) of Arkona, Ontario.

I02 TABULATE CORALS.

Genus Trachypora, Edwards and Halme, 1851.
(Pol. Foss. des Terr. Pal., p. 305.)

Gen. Char. — Corallum dendroid, of compact cylindrical stems,
attached basally to foreign bodies, and composed of conical
corallites which diverge with an increasing curvature from an
imaginary axial line to open on all parts of the free surface.
Corallites essentially polygonal, in close contact, their proper
walls usually not obliterated, and in no case separated by the
intervention of a true ccenenchyma. Interior of the tubes con-
tracted by the deposition of numerous concentric layers of scler-
enchyma, which increase in amount as the surface is approached.
Calices superficially widely distant from one another, arranged
in irregular longitudinal rows, the interspaces between them,
formed by their enormously-thickened lips, being ornamented
with grooves or ridges. Septa represented by radiately-placed
spines or tubercles, or obsolete. Tabulae few, remote, com-
plete. Mural pores generally well marked, but few and
irregular.

Obs. — The genus Trachypora was founded by Miine-
Edwards and Haime for the reception of the single species
T. Davidsoni, from the Devonian formation of France ; and
it was placed by these eminent zoophytologists {loc. cit) in
the family of the Seriatoporidce, in the immediate neighbour-
hood of Deiidropora, Mich., and Rhabdopora, E. and H., both
also founded upon single species. These three types, in fact,
if really capable of generic separation at all, are apparently
most closely allied to one another ; and as I do not possess
any specimens of the two latter, and as their microscopic
structure is wholly unknown, I shall make the few remarks
concerning them which may be necessary in connection with
the present genus, with the anatomy of which I am better
acquainted.

My knowledge of the genus Trachypora is based upon a
minute examination of T. ornata, Rom., and T elegantula,

GENERA OF FAVOSITID^. 103

Bill., both of which are, in my opinion, unmistakably con-
generic with the type-species, T. Davidsoiii, E. and H., and
were so regarded by their respective founders. The investi-
gation of thin sections of these two species has led me to
entirely coincide in all points of substantial importance with
the account given of the genus by Dr Rominger, who unites
it with Dendropora, Mich. (Foss. Corals of Michigan, p. 60,
1877). It becomes quite clear, then, that there is no real
affinity between Trachypora, E. and H,, and Sej^iatopora,
Lam. Not only is the columella of the latter genus totally
wanting in the former, but thin sections place it beyond a
doubt that there exists in Tj^achypora absolutely nothing of
the nature of a coencnchyvia. It is true that the apertures
of the calices are widely removed from one another, and
that the dense calcareous tissue which separates them is
superficially sculptured in various ways ; but tangential sec-
tions (such as fig. 3 c, PI. V.) show that the appearance thus
produced — and mistaken, very naturally, by Milne- Edwards
and Haime as indicating the presence of an abundant coenen-
chyma — is really due to quite a different cause. In reality
there is no ccenenchyma at all, and the essentially polygonal
corallites are in close contact by their walls throughout. The
wide interspaces which separate the openings of the calices
are truly formed by the extraordinary thickening of the walls
caused by the deposition of numerous concentric layers of
sclerenchyma in the interior of the tubes. The actual struc-
ture is, therefore, precisely that of Pac/iypora, Lindst, and
Striatopora, Hall, so far as this point is concerned — with the
difference, that the thickening of the immediate periphery
of the calices is carried to a much more extreme extent,
and that the free surface separating the openings of the
calices exhibits the peculiarity of being ornamented with
grooves or ridges. This last -mentioned feature is, indeed,
the only definite character by which such species of the
genus as T. ornata, Rom., can be separated from PacJiy-
pora, while other species (such as T. Davidsoni, E. and H.,

104 TABULATE CORALS.

and T. eleganhila, Bill.) exhibit the additional peculiarity that
the remote calices are upon the whole distributed in a small
number of vertical rows. Not only is there no true ccenen-
chyma in Trachypora, but the propriety of the step taken
by Dr Rominger in placing the genus among the FavositidcB
is further shown conclusively by the fact that the cavities
of contiguous tubes are placed in communication by means
of a system of mural pores — the importance of this fact not
being diminished by the comparatively small number of these
openings. It should be added that in some forms (including
the type-species, T. Davidsoni) such apertures in the walls of
the corallites have not yet been recognised ; but it may be
confidently expected that these structures will yet be brought
to light by a sufficiently minute examination. Lastly, Milne-
Edwards and Haime state that, in T. Davidsoni, "on ne dis-
tingue pas de cloisons ; " and the same statement will apply to
T. elegantula, Bill. In other cases, however, and especially in
T. ornata, Rom., the septa are quite recognisable as a well-
developed series of spines arranged in vertical rows.

While I am unable at present to recognise any true relation-
ship between Se7'iatopo7'a and Trachypora, I ought to add that
I have had no opportunity of examining microscopic sections
of the former, and that my conclusions are therefore based
upon the published descriptions and figures of Seriatopora.
There is a close general resemblance between such forms of
Trachypora as T. eleganhda, Bill., on the one hand, and certain
forms of Seriatopora {e.g., Seriatopora elegans, Hist. Nat. des
Coralliaires, PI. F 4, figs. '^ a, '^ b) on the other hand ; and
it is possible that a microscopic examination of the latter may
show that this resemblance is based upon a real identity of
structure. All that I can affirm is, that the species of Trachy-
pora assuredly do not possess either a proper ccEnenchyma or
a columella, organs which are said to be present in Seriatopora,
and that there is thus established a wide difference in syste-
matic position. In the same way there is a striking resem-
blance between Trachypora ornata, Rom., and the living Pocil-

GENERA OF FAVOSITW^. 105

lopora acuta, Lam. (see Hist. Nat. des Cor., PI. F 4, fig. 2) ;
but I have no means of knowing how far this resemblance may
express an actual agreement in anatomical structure, and the
former assuredly does not possess the coenenchyma stated to
exist in the latter coral.

As distinguished by Milne- Edwards and Haime (Pol. Foss.
des Terr. Pal., pp. 304, 305), Trachypora is separated from
Dendropora, Mich., by the fact that the " coenenchyma " (that
is, the thickened margin of the calices) is smooth, or almost so,
in the latter, whereas in the former it is adorned by irregular
vermiculate or sub-echinulate striae. The genus Rhabdopora
E. and H., again, is said to be characterised by having four-
sided branches, with an echinulate " coenenchyma," and calices
arranged in simple longitudinal series, the septa being very
distinct and slightly exsert. Professor Martin Duncan, in his
masterly " Third Report on the British Fossil Corals " (Rep.
Brit. Assoc, 1872), concludes — as I think, rightly — that the
maintenance of a generic distinction between Dendropora,
Mich. (1845), and RIiabdopo7^a, E. and H. (185 1), is quite
untenable ; but I am unable to follow this distinguished
authority in his further conclusion that both of these genera are
identical with Seriatopora, Lam., which, in turn, is said to be
inseparable from Pocillopora, Lam., the name of Acropora,
Oken, being rehabilitated for the reception of all of these.
Trachypora, E. and H., is, on the other hand, doubtfully
referred to the Alcyonaria. The researches of Verrill (Trans.
Conn. Acad., vol. i., 1868) have, however, shown that Pocillo-
pora is closely related to the Oculiiiidcs ; and it is highly prob-
able that Seriatopoj^a, whether generically separable or not,
will ultimately be found to occupy a similar zoological position.
Dr Rominger, on the contrary, merges Trachypora under
Dendropo7^a, Michelin, holding that the surface-ornamentation
is a character of merely superficial importance. In this view I
should be quite prepared to concur, if it were once shown that
Dendropora explicita, Mich., the type of the genus, possessed
the internal structure of Trachypora ; but in the absence of any

io6 T/IBULATE CORALS.

information as to the intimate characters of the former, I think
it safer to retain Trachypoi'a in the meanwhile as a distinct
genus. This genus, as will be abundantly evident from what
has been said already, is incontrovertibly referable to the
FavositidcE, and is very nearly related to Pachypoi'a, Lindst.
If, as is very probable, an examination of the minute structure
of Dendropora explicita, Mich., should show that this too is
a Favositoid, then the genus Dendropora, Mich, (including
Rhabdopora, E. and H.), will have to take the place of Trachy-
pora, E. and H., and the classification and arrangement of this
difficult group will have been materially improved.

All the known species of Trachypora, E. and H., are Devo-
nian ; but its union with Rhabdopora would extend the range
of the type into the Carboniferous, and I possess a specimen
from the Wenlock Limestone of Longhope, which appears to be
undistinguishable from Dendropora. It is probable, therefore,
that the genus will ultimately be shown to range from the
Upper Silurian to the Carboniferous ; but its exact limits must
remain at present uncertain.

Trachypora ornata, Rominger, sp.

(PL v., figs. 3-3^.)

Dendropora ornata, Rominger, Foss. Corals of Michigan, p. 6i, PI. XXIII.,
fig. I, and PI. XXIV., fig. 2.

Spec. Char. — Corallum composed of cylindrical stems,
generally about two or three lines in diameter, branching
dichotomously at intervals of half an inch or more. The
openings of the tubes on the surface are oval or circular,
variable in size, the larger ones mostly about two-thirds of
a line in diameter, and either raised above the general surface
by a projecting rim, or apparently level with it. Openings of
the tubes separated by dense calcareous tissue, which is really
formed by the thickening of the walls of the corallites, and
which may separate the actual orifices to their own diameter
or more. The proper walls may or may not be superficially

GENERA OF FAVOSITIDyE. 107

recognisable as subpolygonal lines surrounding each orifice,
and the thickened margins are adorned with tubercles or
ridges arranged in a more or less conspicuously radiate
manner round the calices. Septa represented by rows of
spinules arranged radiately in vertical rows. Tabulae few,
remote, complete. Mural pores few, large -sized, irregularly
distributed.

Obs. — This pretty species is readily distinguished from the
forms most nearly allied to it by the peculiar ornamentation
of the incrassated margins of the calices, which are ornamented
with rows of granules or discontinuous ridges invariably having
a more or less clearly recognisable radiate arrangement (PI. V.,
fig. 3 a). Vertical sections show that the walls of the coral-
lites are greatly thickened (PI. V., fig. 3 b), and that this
thickening is rapidly augmented in amount towards the open-
ings of the tubes ; but considerable differences obtain in the
extent to which this process is carried. In some instances, the
thickening is so great that the actual openings of the corallites
appear to be separated by dense calcareous tissue to their own
diameter or even more ; but in others they are much more
closely approximated, owing to the comparative thinness of the
walls. Vertical sections (PI. V., fig. 3 b) further show that the
walls of the corallites are always distinctly recognisable and
closely contiguous, no coenenchymal tissue being present ; that
the visceral chambers remain open throughout their entire
length, though greatly contracted in diameter by the thicken-
ing of the walls ; that there are a few, remote, horizontal
tabulae ; that the septa are represented by rows of spinules ;
and that the cavities of the tubes are placed in communication
by a few large pores, of the same character as those of Favo-
sites, but quite irregular in their distribution. Tangential
sections (PI. V., fig. 3 c) show the same thickening of the walls
of the corallites as do vertical slices, and show distinctly that
this thickening is due to the deposition of successive thin con-
centrically-disposed laminae of sclerenchyma within the interior
of the tubes. They further show that the actual polygonal

io8 TABULATE CORALS.

walls of the corallites remain quite distinct and unobliterated,
in spite of the thickening to which they are subjected. In
some instances, if the plane of the section is just below the
actual surface, the dense tissue surrounding the cavity of the
visceral chamber may exhibit small discontinuous cavities ; but
these are clearly merely spaces in the interior of the super-
ficial tubercles and ridges surrounding the opening of the
calices (as seen in the lower part of the section figured in
fig. 3 c, PI. V.) Lastly, tangential sections show that the
cavities of the tubes are surrounded by short, blunt, septal
spines. Transverse sections taken at right angles to the axis
of the corallum show no features of special importance.

Formation and Locality. — In shales belonging to the Hamil-
ton formation, at Canandaigua, New York. (Dr Rominger's
specimens are also from the Hamilton group.)

Trachypora elegantula, Billings.
(PI. v., figs. 4-4^-)

Trachypora elegantula, Billings, Canadian Journ., new ser., vol. v. p. 254,

figs. 2-4.
„ elegantula, Nicholson, Report on the Palaeontology of Ontario,

1874, p. 59.
Dendropora elegantula, Roniinger, Report on the Foss. Cor. of Michigan,

p. 63, PI. XXIII., fig. 2.

Spec. Char. — Corallum ramose, of slender, cylindrical stems,
which have generally a diameter of from one to two lines, and
branch dichotomously at angles of about 75°. Corallites
conical, nearly or quite vertical in the centre of the branches,
and curving gently outwards to open obliquely on the surface
in generally four longitudinal rows of calices, sometimes with
supplementary and irregularly-distributed apertures in addi-
tion. The central tubes of the corallites are greatly thickened
by the deposition of concentric layers of sclerenchyma, which
more or less obliterate the proper walls as distinct structures,
though the boundaries of contiguous tubes still remain separate.
The orifices of the calices are oval, their long axes parallel

GENERA OF FAVOSITID.E. 109

with that of the stems, two-thirds or three-fourths of a line in
their long diameter, and about half a line across, surrounded
wholly or for their lower two-thirds by a slightly-elevated rim,
which is sometimes marked with radiating strise. The thick-
ened margins of the calices separate contiguous apertures to a
width about equal to the long diameter of the latter, and form
by their union dense interstitial spaces, which are marked by
slightly flexuous broken strise. Septa apparently obsolete.
Tabulae few in number or seemingly absent. Mural pores not
recognised.

Obs. — The external characters of this species, as given in the
above diagnosis (PI. V., figs. 4 and 4 a), sufficiently separate it
from all the known forms belonging to the genus. The inter-
nal structure, however, presents various points which are as
yet not sufficiently elucidated, the remarkable density of the
corallum rendering the preparation of satisfactory microscopic
sections a matter of exceptional difficulty. In most of its
structural features, T. eleganttila, Bill., does not differ greatly
from such forms as T. ornata, Rom., with which it is undoubt-
edly congeneric ; but the thickening of the corallites by a
secondary deposit of sclerenchyma is carried in the present
form to an extreme extent. This is seen particularly in the
fact (as shown both by transverse and vertical sections) that the
actual walls of the corallites are more or less obliterated (PI.
v., figs. 4 b and 4 r), and are not present as distinct partitions
definitely circumscribing the individual tubes. In the centre of
the stem, where the thickening has not been excessive, the
walls are still distinctly recognisable (PI. V., fig. 4 b) ; but as
the thickening increases in approaching the surface, the definite
lines indicating the proper walls disappear, and the boundaries
of contiguous corallites are now only marked by an obscure but
still quite unmistakable band of thickened tissue, occupying
the place of the wall (PI. V., fig. 4 c). On the surface, the
polygonal margins of the calices — which are quite recognisable
in T. ornata, as ridges surrounding the actual orifices of the
tubes at some little distance — are no longer to be detected at

ixo TABULATE CORALS.

all ; and the calices now appear as if sunk in a dense coenen-
chyma, superficially adorned with discontinuous striae (PI. V.,
fig. 4 a). Moreover, a careful microscopic examination shows
that this dense interstitial tissue is, in parts at any rate, ren-
dered minutely porous by the presence of numerous excessively
small cavities.

The general appearances presented by this species — as
apparently also by the type-species T. Davidsoni, E. and H. —
are entirely such as would support the view entertained by
Milne- Edwards and Haime — namely, that we have to deal
in Trackypora with composite corals, the corallites of which
are sunk in a general coenenchyma. Thin sections, however,
render it abundantly clear that this is not the case, but that the
thickened interstitial tissue between the actual tubes of the
corallites is only due to the deposition of delicate concentric
laminae of sclerenchyma round the visceral chambers, thus more
or less extensively obliterating the true walls. The corallites
are therefore really in close contact, and a true coenenchyma
is wanting. It may further be noted that there exists in the
present species a kind of undulating median partition (PI.
v., fig. 4 c), which seems to separate the corallites on opposite
sides of the frond, or to mark the line along which the four
longitudinal rows of corallites meet centrally.

As regards other points of structural importance, tabulae are
very sparsely developed, and are not always detectable ; though
there can be no doubt of their general existence. Septa appear
to be wanting, so far as my observations go. Lastly, I have
not succeeded in demonstrating the existence of mural pores
to my own satisfaction ; but they are asserted to be present by
Dr Rominger, and I entertain no doubt as to the correctness of
his observations on this point.

Formation and Locality. — Rare in the Hamilton formation
(Devonian) of Arkona, Ontario.

GENERA OF FA VOSITID^. 1 1 1

Genus Vermipora, Hall, 1874.
(Twenty-sixth Annual Report on the State Cabinet of New York, p. 109.)

Professor Hall defines this genus as follows : " Bryozoum
growing in ramose branches, which are composed of small cell-
tubes growing upon one another side by side, without inter-
tubular or cellular substance, and destitute of rays or trans-
verse partitions within the tubes. Tubes diverging from the
centre of the branch, gradually diverging, and opening upwards
on the exterior surface ; each tube forming the apex of the
branch at the time of its origin, and giving place to succeeding
cells in its divero-insf outwards."

More recently, Dr Rominger has published the following
definition of Vermipora, Hall, (Rep. Foss. Cor. of Michigan, p.
68, 1876):—

" Ramified twigs, composed of contiguous, sub - parallel,
cylindrical tubules, multiplying by lateral gemmation, slowly
diverging in their parallel ascending course from a central
imaginary axis, and becoming disjunct near their peripheral
ends, which project on the surface as single proboscidal
siphuncules. Tubes intersected by remote transverse dia-
phragms, and connected by lateral pores. Vertical radiating
crests not observed."

To the above generic diagnosis Dr Rominger adds the fol-
lowing remarks : "Mr Hall places these forms with the Bryozoa,
and gives of their structure a description different from mine.
He has overlooked the principal Favositoid characters of the
tubes, diaphragms and lateral pores ; but I think these organs
can be found in his specimens as well as in those I have under
consideration."

Ods. — Not having had the opportunity of personally examin-
ing any unquestionable examples of this genus, and having no
knowledge of its microscopic structure, it is impossible for me
to supply any data which might serve to clear up the discrep-
ancies between the generic diagnoses given by Hall and

112 TABULATE CORALS.

Rominger, as above quoted. Judging, however, from Dr
Rominger's figures {loc. cit., PI. XXIV.), and accepting the
general accuracy of his observations as regards the presence of
tabulae and mural pores, it appears impossible to doubt that we
have to deal in Vermipora, Hall, with a true Favositoid coral,
and not with a Polyzoan. In fact, Vermipora would not
appear to be structurally separable from Favositcs, except by
the disjunct condition of the tubes towards their superficial
terminations — the limited development of the tabulae and the
irregular distribution of the mural pores being features of minor
importance, and being, perhaps, not always present.

Though I have not had access to any American specimens
which I could unhesitatingly refer to the present genus, my
friend Dr Lindstrom has kindly sent me some examples of a
small coral from the Upper Silurian of Gotland, with the label
Favosites clausus, n. sp,, which appear to me to be unques-
tionably congeneric with Vermipora, Hall. I shall therefore
proceed to briefly describe the structure of these under the
name of Vei^mipora ciatisa, Lindst, sp. ; and I will only add
here, that I am inclined to think it very probable that in reality
the genus Vermipora, Hall, is identical with the previously-
described Fletcheria of Edwards and Haime. The latter
genus is, however, stated to increase by calicinal gemmation,
and to be destitute of mural pores ; and as I have had no
opportunity of examining any specimens of the type-species
{F. tubifera, E. and H.), I shall at present leave it in the
position to which it was assigned by the distinguished French
palaeontologists, and also by Professor Martin Duncan — viz., in
the immediate neighbourhood of Syringopora}

^ It may be observed that there is some resemblance in external appearance
between Vermipora and some of the corals which have been referred to A itlopora ;
and it does not seem impossible that such species of the latter as the A. spicata
of Goldfuss (Petref. Germ., p. 83, PI. XXIX., fig. 3), may prove on microscopic
examination to belong to the Favositida, and to be referable to Vermipora, Hall.

GENERA OF FAVOSITID^E. 113

Vermipora clausa, Lindstrom, sp.
(PI. VI., figs. I- I b.)

Spec. Char. — Corallum forming small sublobate or subramose
masses, composed of nearly cylindrical corallites, which diverge
from an imaginary central axis. Centrally the corallites are in
close contact, and are rendered subpolygonal by mutual com-
pression ; but as they diverge outwards, they become, as a
general rule, more or less completely free, each being enclosed
by its proper wall. Diameter of the corallites about half a line,
the intercalated younger tubes of all sizes below this. Walls
thick, perforated at all points where the corallites are in con-
tact, by numerous irregularly-distributed, circular mural pores.
Septa well developed, in the form of radiating spines. Tabulae
well developed, complete, mostly horizontal, or curved with
their convexities downwards.

Obs. — As before said, I am indebted to Dr Lindstrom for
examples of this species, with the \?^^q[ oi Favosites claustis ;
and I presume that it is a portion of a specimen of this form
which he has figured in a paper on certain Zoantharia Rugosa
in the ' Ofversigt Vetenskaps- Akademiens Forhandlingar ' for
1856, PI. XXXI., fig. 14, under the name of Fletcheria clmtsa.
I have not access, however, to the original of this paper, and
do not know if Dr Lindstrom has published any full description
of the species.

In general appearance the corallum of Vermipora clausa
might well be taken for a small dendroid Favosites, which
has a tendency to assume rather a lobed than a truly branched
character. The largest specimen I have is about ten lines in
length and five lines in its greatest width. The internal struc-
ture is also precisely that of Favosites proper ; and the only
point which justifies generic separation is to be found in the
fact that the tubes invariably become more or less cylindrical
and more or less completely free as their mouths are ap-
proached (PI. VI., fig. i). In the amount of this freedom,
however, there is considerable difference in different speci-

H

TI4 TABULATE CORALS.

mens. In some examples the coralHtes, though still retaining
their cylindrical form, are very nearly in contact to their
calices ; whereas in others the tubes become completely dis-
junct long before their mouths are reached. In all cases,
however, the corallites are in close contiguity in all the cen-
tral portions of the skeleton ; and here their walls are always
perforated by irregularly distributed mural pores, the condition
of parts being, therefore, precisely the same as in Favositcs.
The walls of the corallites, though moderately stout, are not
thickened by a conspicuous deposit of sclerenchyma, as in
Pachypoi'a; while the calices are rounded, and often slightly
oblique, smaller ones being intercalated among those of aver-
age dimensions. Dr Lindstrom has noticed the fact that the
calices are occasionally closed by an opercular growth ; and the
exterior of the wall in the free portions of the tubes exhibits
numerous fine encircling striae. Transverse sections (PI. VI.,
fig. I a) show that the tubes In the centre of the corallum are
subpolygonal, with moderately thick walls, the lines of division
between them always remaining quite distinct. At the same
time, well-developed splniform septa are brought into view.
Longitudinal sections (PI. VI., fig. i b) precisely resemble
those of a Favosites, exhibiting septa and mural pores, along
with well-developed complete tabulae, which may be horizontal,
or may be curved with their convexity downwards.

Formation and Locality. — Upper Silurian, Gotland, Coll., Dr
Gustav Lindstrom.

Genus Romingeria, Nicholson.

Ouenstedfia, Rominger, Fossil Corals of Michigan, p. 70, 1876.
[Non Qnensfedtia, Morris and Lycett, 1854.]

Gen, Char. — Corallum lax, spreading ; resembling Anlopora
in its general appearance, but only attached basally, and free
throughout the greater part of its extent. Corallites cylindri-
cal, annulated, multiplying by lateral gemmation, and typically
producing new tubes in umbellate whorls or verticils, which

GENERA OF FAVOSITID.E. 115

are placed at short intervals. Where their walls are in contact,
their visceral chambers are placed in communication by means
of mural pores. Tabulae complete, remote, apparently not dis-
tinctly infundibuliform. Septa represented by vertical rows of
spinules.

Obs. — The type of this genus is the singular coral described
by Billings under the name of Aulopora umbellifera (fig. 19),
from the Corniferous Limestone of North Am-
erica. It was provisionally left by Billings, and
subsequently by myself, in the genus Atdopora,
upon the ground that its internal structure was
imperfectly known, but both of us stated that
it would probably prove to be the type of a new
genus. At a later date Dr Rominger succeeded
in establishing the important fact that mural ^^g- i9- — Portion

of the corallum of

pores are present m this species, and he there- Romingeria um-
fore properly removed it to the family of the i"-W<-'ra, Biii. sp.,

^ i- J J from the Corni-

Favositidce^ and raised it to the rank of a genus ferous Lhnestone

1 ^1 P ^-. , 7, • /-ni • 1 • .' of Canada, of the

under the name 01 (Juensteaha. 1 his designation natural size.
would of course have been retained by me but
for the fact that it has, unfortunately, been employed as early
as 1854, by Morris and Lycett, for a genus of Lamellibranchiate
Molluscs. Under these circumstances, I have great pleasure in
proposing for the genus the title Romingeria, in honour of one
who has so largely contributed to the elucidation of the fossil
corals of North Am.erica.

In many respects Romingeria is a type of special interest, as
affording us a transitional link between the families of the Favo-
sitidcs and the SyringopoiHcicE, It differs from Atdopora, to which
it was originally referred, by its erect mode of growth, in the
disposition of the branches (as a rule) in successive verticils, and
more especially in its perforate walls. In general habit it does
not differ much from some species of Syringopora ; and if we
imagine its mural pores to be converted into hollow connecting
processes, it would be difficult or impossible to separate it from
this genus. The existence, however, of mural pores, as first

ii6 TABULATE CORALS.

demonstrated by Rominger, proves that it is properly referable
to the FavositidcE, among which its true place would seem to be
in the neighbourhood of Vennipora, Hall. It differs from the
latter, in fact, principally by the lax spreading mode of growth
of the corallum, and by the much greater extent to which the
corallites are disconnected from one another.

Dr Rominger has described a species from the Niagara Group
of North America {loc. cii., p. 71); but I am only acquainted
personally with the type-species, R. tLmbellifera, Bill,, of which
I subjoin a short description. I regret, however, that the state
of preservation of my specimens is such — owing to silicifica-
tion — that I have been unable to procure satisfactory micro-
scopic sections, and that I can therefore merely give such
characters as can be learned by the ordinary methods of
examination.

Romingeria umbellifera, Billings, sp.
(Fig. 19.)

Aiilopora timbci/ifera, Billings, Canad. Journ., new sen, vol. iv. p. 119,

fig. 21.
,, u/iibel/ifera, Nicholson, Report on the Palseontology of Ontario, p.

43, PI. VI., fig. 4 (poor figure).
Qitenstedtla n/iibe//ifera, Rominger, Rep. Foss. Cor. Michigan, p. 70, PI.

XXXIIL, fig. 3.

Spec. Char. — Corallum erect, lax, spreading, of cylindrical
corallites, with a thick annulated wall, adorned with fine en-
circlincr striae. Diameter of the corallites about one line. The
primary stems remain undivided for a distance of a quarter of
an inch or more, and then give origin to a cluster of corallites
in an umbellate manner, one or more of these proceeding to
proliferate in a similar manner, and at a similar interval, and
the process being repeated till a loosely fasciculate corallum is
produced. The number of corallites in a single verticil varies
from five or six to as many as ten or twelve, and they are at
first closely in contact with one another, the union of their
walls often extending to a distance of two or three lines from

GENERA OF FAVOSITID^. 117

the point of origin from the parent tube. Ultimately, they be-
come more or less completely free — radiating outwards, like the
spokes of a wheel — and one or more are continued beyond the
general circle of the whorl to give rise to a new umbel. Walls
thick, the visceral chambers of the corallites, where the latter
are in contact, being placed in connection by distinct mural
pores (Rominger), Tabul£e remote, complete, so far as ob-
served horizontal. Septa represented by from six to ten
vertical rows of strong splnules.

Obs. — I have little to add to the above specific diagnosis,
which embodies all the important characters which I can
gather from an examination of the specimens in my possession.
The existence of mural pores cannot be determined from any
of my examples, but Dr Rominger's figures (heliotypes) prove
their presence beyond all question. I think it quite likely that
Dr Rominger is correct in regarding Azdopora conmta, Bill.
(Can. Journ., new sen, vol. iv. p. 118, fig. 20), as really founded
upon fragments of the present species. I have, however, vari-
ous specimens which seem to belong to Aulopora cornuta as
regards their general characters, but which agree with Aulopora
proper in being parasitic ; so that I must at present leave the
identity of this form with Romingeria 2uubellifera an open
question.

Formation and Locality. — Rare in the Corniferous Limestone
(Devonian) of Port Colborne, Ontario.

Genus Alveolites, Lamarck, 1801.

(Syst. des Anim. sans Vert., p. 375.)

Gen. Char. — Corallum massive, incrusting, or ramose, com
posed of contiguous compressed corallites, which possess thin
•walls, and open obliquely upon the surface by subtriangular or
semilunar calices. Septa sometimes obsolete, but often present
in the form of longitudinal rows of spinules, which may be
equally developed, or may be reduced to a single, double, or

ii8 TABULATE CORALS.

treble row by the suppression of the others. Tabulae well
developed, complete. Mural pores generally few in number,
of large size, and irregular in their distribution.

Obs. — There is no genus in the entire series of the Favo-
sitidcB which presents greater difficulty than the present one,
as regards its satisfactory definition and separation from allied
types. So much so is this the case, that a strong disposition
has been shown by some of our most distinguished palaeontolo-
gists to reject the genus Alveolites altogether, and not without
reason, since it is certain that the forms which have at various
times been included under this name are of very different affin-
ities. The difficulties which environ this subject have been
elsewhere discussed at some length by Mr R. Etheridge, jun.,
and myself (Journ. Linn. Soc, vol. xiii. p. 353, 1877); and I
shall avail myself largely of the memoir just referred to in what
follows. Since this paper was written, however, I have been
able to obtain much additional material throwing light upon the
genus, and am therefore able to speak more decidedly upon
some points which at that time appeared doubtful, as well as to
modify in some particulars the opinions therein expressed.

The genus Alveolites was originally founded by Lamarck in
the first edition of the ' Systeme des Animaux sans Vertebres '
(published in 1801), p. 375, for the reception of a single Devo-
nian species which he described under the names of A. subor-
bictilaris and A. escharoides, and for which the former title has
been subsequently retained. The original definition is, " Poly-
pary stony, thick, globular, or hemispherical, formed of numer-
ous concentric layers, which are superimposed one upon the
other, each layer formed by the union of alveolar, subtubular,
prismatic, contiguous cellules [or tubes], forming a network on
the surface." In the Hist. Nat. des Anim. sans Verteb. (pub-
lished in 1 8 16), vol. ii. p. 184, the same definition is given with
very slight alterations, the principal change being that the genus
is now made to include incrusting forms. In the second edition
of Lamarck's Hist. Nat. des Anim. sans Verteb. (published in
1836), the portion relating to the corals was revised by Milne-

GENERA OE FAVOSITIDyE. 119

Edwards, and the genus Alveolites is defined as follows (vol. ii.
p. 285) :—

" Corallum stony, sometimes incrusting, sometimes free and
massive, formed of numerous layers which are concentrically
superimposed upon one another, each layer composed of tubu-
lar, alveolar, prismatic cellules, which are somewhat short, and
form a network on the surface." Four species of the genus
were recognised by Lamarck, of which A. suborbicularis and A.
escharoides have been subsequently united with one another.
A. viadreporacea is stated by Milne-Edwards to be a Pocillo-
pora, and A. incrustaus appears to be a Polyzoon. To the
above four species Milne- Edwards added, in the work just
quoted, four others, of which A. ttibiporacea and A. millc-
poracea appear to be referable to Favosites ; A. clavata may
perhaps be a Chcetetes; and A. infundibtUifera was afterwards
placed by Edwards and Haime in a new genus under the
name of RoemeiHa.

Without taking up time by discussing the views entertained
as to the characters of the genus Alveolites, and the different
forms referable to it, by Goldfuss, De Blainville, Michelin,
Steininger, D'Orbigny, and other well-known palaeontologists,
we may pass on to consider the opinions expressed by Milne-
Edwards and Jules Haime in their great works on the fossil
corals. In the Introduction to the ' Monograph of the British
Fossil Corals' (Palaeontographical Society, 1850, p. Ix), these
distinguished authorities place the genus Alveolites in the group
of the Favositidae proper, characterised by the presence of well-
developed tabulae, the existence of mural pores, and the rudi-
mentary condition of the septa. They define the genus as
possessing a " corallum composed of superposed strata of
corallites very similar to those of Favosites, but much shorter,
and terminated by an oblique semicircular or subtriangular
calice, the edge of which projects on one side." The type-
species of the genus is A. spongites, Steininger {^=A. suborbi-
eularis, Lamarck). In their ' Polypiers Fossiles des Terrains
Paleozoiques ' (p. 254), the same authors in the succeeding year

I20 TABULATE CORALS.

redefine Alveolites as follows : " Corallum forming a convex
or dendroid mass. Calices oblique, subtriangular, or semi-
circular, presenting interiorly a longitudinal protuberance which
is opposed to two other smaller protuberances. These emi-
nences appear to represent the primary septa, and no other
traces of the septal apparatus can be detected. The walls are
simple, well developed, pierced with a small number of mural
pores. The tabulae are complete and horizontal." After
giving a history of the genus, the authors just quoted remark
that the elongated teeth or eminences above alluded to consti-
tute the most remarkable feature of the genus Alveolites, and
that they are to be regarded as so many primary septa, the
other three which form the normal cycle of six being aborted.
They further add that one of these three septal teeth is always
more pronounced than the other two, and that these latter may
be wholly wanting.

In the * Histoire Naturelle des Coralliaires ' (vol. iii. p. 263,
i860), Milne - Edwards makes the following remarks as to
Alveolites: "The most striking character of y^/z'^^//V^.s- is fur-
nished by the septal system, which is represented by three teeth
or vertical projections — one situated on the inside face of the
outer lip of the calice, the others opposite the preceding, upon
the inner lip of the corallite, and sometimes rudimentary. The
calices are oblique, subtriangular, or subhemispherical. Walls
simple, well developed, and pierced by a small number of
pores. Tabulae complete and horizontal. . . . The elon-
gated teeth or vertical projections which we see in the interior
of the visceral chambers of the corallites /"^rw the most peculiar
character of Alveolites, and recall the three principal septa
which characterise the orenus Heterocoenia amongst the As-
trseidae. . . . It is also worthy of note that one of the septal
projections is more developed than the other two, and often it
alone may exist."

In briefly analysing the above, it will be obvious, in the first
place, that Lamarck's definition of the genus Alveolites does
not contain a single character which would at the present day

GENERA OF FAVOSITID.E. 121

be regarded as of generic importance at all ; so that the ulti-
mate existence of the genus will depend upon whether the type-
species, A. s2ibo7^bicula7'is, Lam., can be shown to possess char-
acters which separate it generically from allied forms. In the
second place, the various definitions given by Milne-Edwards
and Haime yield, upon collation, the following characters as
essentially distinctive of the genus Alveolites as understood
by them : (i.) The corallites are furnished with lamellar walls,
and are not united by any coenenchyma. (2.) The visceral
chamber is traversed by well - developed horizontal tabular.
(3.) Mural pores, comparatively large and few in number,
are present. (4.) The corallites are oblic]ue, shorter than in
Favosites, and terminated by oblique, semilunar, or siibtrian-
gular calices. (5.) There exist in the interior of each corallite
three elongated teeth, which represent the primary septa, and
of which one is always larger than the others, and may be the
only one present. (6.) The corallites are arranged in the mas-
sive and incrusting forms in superimposed layers.

Alveolites sztborbicularis, Lam., the type -species, possesses
all the above-mentioned characters, and is therefore, to begin
with, clearly a member of the Favositidae proper. In order,
however, to establish the validity of the genus Alveolites, it is
further necessary to prove that A. suborbic^daris is generically
separable from Favosites ; and there are only two of the above-
mentioned characters — namely, the obliquity of the calices and
the presence of septal teeth — which require special consideration
in this connection. Moreover, even if the generic distinctness
of ^. suborbieularis and immediate allies be satisfactorily estab-
lished, there still remain various forms more or less resembling
this, which nevertheless differ considerably from it in minute
structure, and which must therefore be referred to different
groups.

To the above remarks, taken from the paper already referred
to, was added a brief account of the principal types of structure
which are recognisable in the various forms which have been
at different times included under Alveolites by different palaeon-

122 TABULATE CORALS.

tologists, and which externally resemble this genus more or less
closely. In most of the views therein expressed, I am still quite
willing to concur, but the further observations which I have
made enable me to state these views in a more definite form
than was at that time possible, and also to make some modifi-
cations in them. The results, then, of my inquiries, combined
with those formerly arrived at by my colleague and myself,
are briefly as follows : —

1. Taking Alveolites suborbicularis, Lam,, as the type of
Alveolites, the genus may be usefully retained, but the pres-
ence of septal teeth must be abandoned altogether as a generic
distinction, and we must include under the same head forms
such as A. Labechei, E. and H., and A. Goldftissi, Bill., which
have numerous septa, or in which the septa are obsolete. On
this view. Alveolites will include forms which agree with Favo-
sites in all essential characters, save only the possession of
oblique calices and narrow compressed or triangular coral-
lites. I fully admit that the characters just mentioned, when
standing alone, cannot be strictly regarded as of generic value,
and that the most rigidly scientific course would be to merge
Alveolites in Favosites. This course, however, would render
the genus Favosites an extremely unmanageable one, and upon
the ground of practical convenience I prefer separating Alveo-
lites by means of the readily recognisable character of the reclined
corallites and oblique calices. All the species thus placed in
Alveolites agree with one another and with Favosites proper in
having thin-walled corallites, without any excessive thickening
of the terminations of the tubes, and they are thus distin-
guished both from Pachypora and from Ccenites, with which
they are otherwise closely allied. I include in this group
Alveolites suborbictdaris, Lam., A. Labechei, E. and H., A.
Goldfussi, Bill, A. Indianensis, Rom., and all forms related
to these.

2. Some of the forms which have been referred to Alveolites
are properly placed under the genus Pachypora, Lindst, as
shown by the thickening of the interior of the tubes by a dense

GENERA OF FAVOSIT/D.E. 123

secondary deposit of sclerenchyma. As has previously been
pointed out, this is the case with the so - called Alveolites
Fischeri, Bill., and A. frondosa, Nich. ; and I have no doubt
that other forms, both of the expanded and ramose type, will
ultimately prove to be referable to Pachypora, rather than
to Alveolites as here defined.

3. The forms grouped under Ccenites, Eichw., so far as pro-
perly placed under this head, may be distinguished from
Alveolites by the form of the calices, but more especially by
the great thickening of the interior of the tubes in the neigh-
bourhood of their mouths. As will subsequently be seen,
therefore, Ccenites bears the same relation to Alveolites that
Pachypora does to Favosites, while it has some special features
in addition.

4. The forms which have been described as Alveolites septosa,
Flem., and A. depressa, Flem., are closely allied to ChcBtetes
radians, Fischer, and must be removed to the genus Chcetetes.

Returning now to the genus Alveolites as here defined, the
form of the corallum appears to be very variable. Alveolites
suborbicularis, Lam., the type of the genus, appears really to
be almost always in the form of irregular masses which are
formed of concentrically disposed layers which have grown
parasitically round some foreign body. In other forms, how-
ever, such as A. Labechei, E. and H., and A. Goldftissi, Bill.,
the form of the corallum is that of a flattened, sometimes gib-
bous expansion, which is covered below by a wrinkled epitheca,
and only exhibits calices upon its upper surface. Other forms,
again, such as A. Rcemeri, Bill., are dendroid ; but the various
ramose corals which have been included under Alveolites will
require to be subjected to a careful microscopic examination
before their true affinities can be positively asserted. Lastly,
so far as I have seen, no true Alveolites, in the sense here
understood, has the form of an erect frondose expansion,
attached basally, and having its free surfaces entirely covered
with calices.

124 TABULATE CORALS.

In the most typical species of Alveolites, the corallites are
excessively oblique to the principal plane of the corallum,
those which open on the circumference of the mass most so, and
those in its centre least, A. stiborbiculai'is. Lam., offers the
extreme type of this condition, while A. Indianensis, Rom.,
though an unquestionable Alveolites, presents the minimum
amount of obliquity of its tubes. It has been pointed out by
Lindstrom that A. Fottgtii, E. and H., primitively possesses
erect corallites, which only become reclined in the course of
growth ; and upon this ground this high authority has placed
the species in Favosites. Upon the whole, however, though
formerly disposed to adopt the same view, I think it safer to
go by the adult characters of the corallum, which would seem
to place this curious transitional form in Alveolites.

Owing, also, to the obliquity of the corallites, the calices in
Alveolites open obliquely upon the surface, one lip being shorter
than the other, and the aperture being more or less transversely
elongated, its shape being in general subtriangular, semilunar,
or subrhomboidal.

The zvalls of the corallites in Alveolites are invariably thin,
as conclusively shown by thin sections ; there is no marked
thickening due to the deposition of concentric lamella; of scler-
enchyma in their interior, nor are the tubes notably, or as a
rule at all, expanded towards their mouths. All forms re-
sembling Alveolites in appearance, but with abnormally thick-
ened walls, must find a place either in Pachypoi'a, Lindst, or
in Coenites, Eichw.

The imtral pores are usually few in number, and of compara-
tively large size ; but it is certain that this character cannot be
used as one of generic value, precisely the same feature occur-
ring in Pachypora.

The septal system varies much in its development in Alveo-
lites. As has been seen, Milne-Edwards and Haime regarded
the presence in the interior of each corallite of three elongated
teeth or septal ridges, which may be reduced to one, and which
represent the septa, as the leading character of the genus. I

GENERA OF EAVOSITJDM. 125

am, however, quite satisfied that this view is untenable, and
that the condition of the septa is too variable to allow of its
being used as a generic character. A. siiborbicularis, Lam.,
seems often to possess such a single septal ridge in the interior
of each corallite (see fig. 20, and PI. VI., fig. 2) ; but an exami-
nation of a number of well-preserved specimens from the Eifel
has convinced me that it is excessively difficult to detect this
feature even in the most perfect examples, and that it is seem-
ingly really not invariably present, since it is only occasionally
that such a structure can be made out by thin sections, so far as
I have seen. It may be freely conceded, however, that certain
species have the septa reduced to one or three longitudinal
ridges, though no more than a specific value can be assigned
to this. On the other hand, A. Labec/iei, E. and H,, though
stated by Edwards and Haime to possess a "slightly devel-
oped" or "very indistinct" septal ridge, like that of A. stibor-
bicularisy can be conclusively shown by microscopic sections to
possess numerous vertical rows of septal spines (PI. VI., figs.
3 and 3 a) precisely similar in their characters to those of F.
Hisingeri, E. and H., and other species of Favosites. The same
feature is equally observable in some other species. In certain
types, again, such as A. Goldftissi, Bill. (PI. VI., fig. 4), the
septa appear to be entirely obsolete, no traces of their existence
being observed in thin slices. Upon the whole, then, we must
regard the development of the septa in Alveolites as quite
variable, and as affording characters of no more than specific
importance.

Lastly, the tabulae in Alveolites are always well developed,
and are complete and essentially horizontal. These structures,
however, present no features of special importance. .

The known species of Alveolites, as here defined, are confined
to the Upper Silurian and Devonian periods ; and the two
species which I shall select for brief description as illustrating
more fully the characters of the genus are A. suborbicularis,
Lam,, and A. Labecliei, E. and H.

126 TABULATE CORALS.

Alveolites suborbicularis, Lamarck.

(PI. VI., figs. 2-2 /;.)

Alveolites suhorbicularis, Lamarck, Hist, des An. sans Vert., vol. ii. p. iS6,
1816.

„ escharoides, Lamarck, ibid., p. 186.
Calamopora spongites, var. tuberose, Goldfuss, Petref. Germ., p. 80, PI. XXVIIL,

figs. I ^-i ^ (caet. exclusis), 1829.
Favosites spongites (?), Phillips, Pal. Foss., p. 16, PI. VIIL, fig. 23, 1841.
Alveolites suborbiciilaris, Milne-Edwards and Haime, Pol. Foss. des Terr. Pal.,

p. 255, 185 1, and Brit. Foss. Cor., p. 219, PI. XLIX.,figs. i and i a, 1853.

Spec. Char. — Corallum forming masses of considerable size
and variable form, consisting of concentrically superposed layers,
attached parasitically to some foreign body, and having an
irregularly elevated surface. Corallites very oblique, com-
pressed, mostly subtriangular, with a long convex and two
short concave sides, but very variable in form, though never
regularly polygonal or cylindrical. Long diameter of the tubes
about one-third of a line, transverse diameter about one-sixth
of a line. Walls moderately but not excessively thick, not in-
crassated towards the terminations of the tubes, and pierced by
few remote mural pores. Septa represented only by a single
longitudinal ridge, which does not appear to be constantly
present. Tabulae numerous, close-set, horizontal, complete.

Ods. — The specimens from which the above description is
taken were collected by myself in the Eifel, and agree in all
respects with the figures given by Goldfuss (Petref. Germ., PI.
XXIX., figs. I a-i e] Milne-Edwards and Haime add figs \f-
I k of the same plate, but I think these belong to a different
species). These figures give an excellent idea of the general
form and appearance of this species ; and I have not, therefore,
thought it necessary to give an illustration of one of my own
specimens. So far as I can judge at present, I think that the
name of A. suborbicularis will have to be restricted to the
specimens which have the habit of forming irregularly gibbous
masses, composed of successive concentric strata enveloping

GENERA OE EAVOSITIDyE. 127

some central foreign body. It is not that any particular stress
can be laid upon the mode of growth per se ; but so far as my
observations have gone as regards this species, this peculiar
habit is only found in specimens which have a special internal
structure ; and, under these circumstances, it becomes a charac-
ter of specific value. On the other hand, there occur along with
the preceding many specimens which form flattened or sub-
hemispherical expansions, having their under surface covered
by a wrinkled epitheca, attached to some foreign object by a
pedunculate base, having the calices confined to the upper sur-
face only, and not exhibiting any composition of the corallum
out of concentric layers. Specimens of this type in other re-
spects nearly resemble A. siLborbictdaris, Lam., and they might
be easily, and I believe sometimes have been, confounded with
the latter. So far as I have yet examined such specimens,
however, I find them to differ from the encrustingr and lami-
nated specimens which constitute the true A. sudor bicularis,
Lam., in various points of their internal structure, and especially
in the possession of numerous unusually strong spinose septa.

The only points in the anatomy of A. stiborbictilai^is to which
I need draw attention are the condition of the septa and the
tabulae. According to Milne-Edwards and Haime, the outer
or under side of each of the calices
" bears interiorly a small elongated
ridge, which appears to represent a
septum, and is placed opposite to a
small notch" (Brit. Foss. Cor., p. 219).
Such septal ridges have been well
figured by Goldfuss, and I have re-
produced his drawing in order to show
their character (fig. 20). I am not able
to assert, however, that I have sue- ¥\g. 20.— CaWcts oi Alveolites sui>-
ceeded in detecting their presence by f"'?^' l-";-' ^'^fy ^";

o ir J Jaiged, showing the single septal

an examination with a lens of any of "^ge. Devonian, Eifei. (After

... 'IT Goldfuss.)

the specimens in my possession, and I

think that little specific value can be attached to a character

128 TABULA I'E CORALS.

so uncertain and so difficult of recognition. This opinion is
strongly supported by the appearances presented by tangential
sections (PI. VI., fig. 2 a). In these, the characteristic com-
pressed form and the moderately thick walls of the corallites
can be admirably observed ; but the single septal ridge above
alluded to can only be made out occasionally, and never, so far
as I have seen, in more than quite a small proportion of the
tubes. It does not seem, therefore, to be of constant occur-
rence, and no other traces of septa can be detected.

In longitudinal sections (PI. VI., fig. 2 b) the chief feature
observable is the abundance of the horizontal and complete
tabulae, no traces of septa being recognisable.

Fojnjiation and Locality. — Abundant in the Devonian Lime-
stone of Gerolstein and Bensburg in the Eifel. I do not yet
feel certain if any of the specimens which I possess from the
Devonian limestones of Devonshire are really identical with
this species, though some certainly present a close resemblance
to it. None of the species oi Alveolites from the Devonian of
North America that I have examined, or that have been figured
or described by other observers, seem to be referable to this
species.

Alveolites Labechei, Edwards and Haime.

(PI. VI., figs. 3 and 3 a.)

Favosites spoiig'iies (pars), Lonsdale, in Murchison, Silurian Syst., PI. XV.,

figs. 8-8 ^ (cffit. exclusis), 1839.
Alveolites Labechei, Milne-Edwards and Haime, Pol. Foss. des Terr. Pal., p.
257» 1851.
„ Labechei^ Milne-Edwards and Haime, Brit. Foss. Cor., p. 262, PL

LXL, figs, d-e b, 1854.
„ Grayi, Milne-Edwards and Haime, Pol. Foss. des Terr. Pal., p.

258, 1851, and Brit. Foss. Cor., p. 262, PI. LXL, figs. 2-2 a.

Spec. Char. — Corallum massive, attached to foreign bodies
by one point of its base, and forming a flattened expansion
with a slightly convex or irregularly elevated surface, the upper
surface being occupied by calices, while the lower surface may
be in large part similarly occupied, or may be covered with a

GENERA OF FAVOSITID.E. 129

concentrically-wrinkled epitheca. Average size of the corallum
from an inch or less up to three inches in diameter, with a
height of from five to fourteen lines. Corallites extremely
oblique, compressed, from one-third to one-half of a line in
their long diameter, and less than this in their short diameter.
Calices upon the upper surface very oblique, subtriangular, or
somewhat lozenge-shaped, usually bounded by one long and two
short curved margins ; upon the lower surface, where present,
usually less oblique, and often irregularly polygonal. Septa
numerous, in the form of pointed spines, which have a marked
upward direction, and extend into the visceral chamber to about
one-third of its diameter. Tabulae numerous, complete, hori-
zontal. Mural pores apparently comparatively numerous and
of no large size.

Obs. — This is one of the most abundant of the corals of the
Wenlock Limestone of Britain. If the Devonian A. siiborbiai-
laris, Lam., be considered, as has here been done, to include only
forms which grow into irregular masses composed of superposed
concentric strata of corallites, then the present species is easily
distinguished from it by the difference of its ordinary habit. It
forms flattened expansions, attached by a pedunculate base, and
usually having part of the lower (as well as the upper) surface
covered by calices. Sometimes almost the whole lower surface
is so occupied, but generally a portion seems to have been pro-
tected by an epitheca. In general form, therefore, y^. Labeckci,
E. and H., resembles the A. Goldfussi, Bill., of the Devonian
of North America; but the latter is readily distinguished by the
much larger size of the calices and the total absence of septa
(PI. VI., fig. 4). Milne-Edwards and Haime have separated
Alveolites Grayi from Alveolites Labechei, upon the ground that
" its calices are always larger, and are limited by walls that are
thicker in proportion to the size of the corallites." After a
careful examination, however, of both of these forms, I am
forced to come to the conclusion that they are not specifically
separable, the more especially as single specimens are not un-
common in which the calices have in parts the long diameter of

I

I30 TABULATE CORALS.

those assigned to A. Labechei (" somewhat more than one-third
of a Hne "), while in other parts the long diameter of these open-
ings is that of A. Grayi (" about half a line "). Moreover, thin
sections show that they agree with one another in their internal
structure, this exhibiting a feature unusual in the genus Alveo-
lites— namely, a well-developed system of septa. These septa
are excellently seen by means of thin tangential and vertical
sections (PI. VI., figs. 3-3 a), and have the form of a circle of
radiating spines, of variable number (often ten or twelve), ex-
tending into the interior of the tubes, and sometimes reaching
nearly to the centre of the visceral chamber. In longitudinal
sections (PI. VI., fig. 3 a) these septal spines are seen to form
vertical rows, and to be generally markedly directed upwards,
or towards the mouths of the tubes. Owing to this latter fact,
they often look, when seen in transverse sections (PI. VI., fig. 3),
as if they were not actually connected with the wall of the tube.
Longitudinal sections show the presence of numerous complete
tabulae, and occasionally of mural pores, the latter seemingly
more numerous and smaller than is usual in Alveolites. Both
kinds of sections show that the walls of the corallites are in no
wise abnormally thickened, and ^. Labechei, E. and H., is thus
shown to belong properly to Alveolites as here understood.

Formation and Locality. — Abundant in the Wenlock Lime-
stone of Benthall Edge, and Dormington Quarry near Stoke-
Edith. Also in the Wenlock Limestone of Gotland. It has
not been hitherto detected in the corresponding formation of
the Niagara Limestone of North America, but species of the
same general type are abundant in the Devonian of Europe and
North America.

Gemis CcENiTES, Eichwald, 1829.

(Zool. Spec, t. i. p. 179.)

Limaria, Steininger, Mem. Soc. G^ol. de France, t. i. p. 339, 1831.

Gen. C//rt;r.— Corallum usually dendroid or frondescent, rarely
submassive. Corallites compressed, thin-walled in the centre of

GENERA OE EAVOSITID^. 131

the corallum, but immensely thickened in the neighbourhood of
their mouths by means of a dense secondary deposit of scleren-
chyma, the proper walls nevertheless always remaining distinct.
Visceral chamber reduced to a fissure in the vicinity of its termi-
nation, and opening upon the surface by a narrow transversely-
elongated slit-like calice, one lip of which carries two tooth-like
projections, which face a single similar tooth springing from
the opposite lip. Septa represented only by the calicine teeth
just spoken of. Tabulae well developed, complete, horizontal.
Mural pores moderately numerous, large-sized, irregularly dis-
tributed.

Obs. — The genus Cceitites was originally founded by Eich-
wald [loc. cit), and was subsequently described by him
(Lethcea Rossica, vol. i. p. 457) as comprising dendroid or
lamellar and encrusting corals, with semicircular or triangular
calices, provided with a single rudimentary septal ridge upon
their lower lips, the corallites being united by an abundant
" ccEnenchyma." Milne-Edwards and Haime (Pol. Foss. des
Terr. Pal., p. 301) also suppose that a " coenenchyma " is pre-
sent, and they describe the septal system as consisting typically
of three teeth, two on one margin of the calice and one on the
other. The same authors include the genus among the Pocil-
loporidce, though they subsequently express a doubt whether it
should not rather be removed from the Actinozoa and placed
among \}i\^ Polyzoa (Brit. Foss. Cor., p. 276). Professor Martin
Duncan (Third Rep. on Brit. Foss. Cor. ; Rep. Brit. Ass.,
1 87 1, p. 130) also assumes the existence of a "coenenchyma"
in C(Biiites. Dr Lindstrom (Nigra Anteckningar om Anthozoa
Tabulata, Ofversigt af Vetensk. Akad. Forhandl., 1873) con-
siders that Coenites may possibly be referable to the Polyzoa ;
but, somewhat inexplicably, he regards Alveolites sub orbicularis,
Lam., and its allies as belonging to this genus. Mr R. Ethe-
ridge, jun., and myself pointed out (Journ. Linn. Soc, vol. xiii.
p. 361), from an examination of Ccenites orientalis, Eichw., that
probably there existed no true coenenchyma in Ccenites, and in-
dicated that this generic name might need to be suppressed in

132 TABULATE CORALS.

favour of Alveolites, Lam. Lastly, Dr Rominger (Foss. Corals
of Michigan, p. 43) placed the genus in the Favositidce, in the
immediate neighbourhood oi Alveolites, from which he regards
it as differing only by " more conical stout-walled tubes of less
compressed and more rounded form in the central or basal parts
of the polyparia."

The true structure and affinities of Coenites, Eichw., can be
determined with the greatest certainty by means of thin micro-
scopic sections ; and these show that the genus is not only not
Polyzoan in its relationships, but that it is in all respects pro-
perly referable to the Favositidcs, standing upon the whole
nearer to Pachypora than to Alveolites. Thus, thin sections
show that the tubes are not only tabulate, but that they have
the more important feature of being placed in communication
with one another by means of a well-developed system of
" mural pores,'' which are precisely similar in all points of im-
portance to the pores of Favosites, and which only differ from
these in being irregularly distributed. Moreover, there is no
" coenenchyma^' present in the corals of this genus, as has been
generally supposed. On the contrary, the corallites (PI. VI.,
fig. 5 a) are in close contact throughout their entire length, and
their walls are also everywhere quite distinct. In the centre
of the corallum the tubes have quite thin walls, and present
no feature by which they could be distinguished from the coral-
lites of a ramose Favosites. Just before reaching the surface,
however, each tube bends abruptly, often dividing at the same
time, and the wall for the rest of its course is immensely thick-
ened by a dense secondary deposit of sclerenchyma. In this
constriction of the visceral chamber near its mouth, the species
of Ccenites agree with those of Pachypora, Lindst. ; but in the
former the thickening is rigidly confined to a narrow external
band, and does not affect the internal parts of the corallum at
all ; whereas in Pachypora the thickening affects the tubes
throughout their entire length, and merely attains its maximum
as the mouth is approached. Furthermore, the corallites in
Pachypora are not markedly compressed or oblique, and are

GENERA OF FAVOSITID.E. 133

equally thickened all round, so as to have their calices sur-
rounded by tumid margins of equal thickness, and mostly
rounded or subpolygonal in form. On the other hand, in Coenites
the thickening affects principally the upper aspects of the tubes ;
and hence the calices assume the form of long narrow slits or
fissures, the length of which greatly exceeds the width (PI. VI.,
fig. 5). Lastly, in Pachypora there are usually numerous short
radiating septa, in the form of tubercles or spines. No struc-
tures, however, can be recognised in Ccenitcs as representing
the septa in the actual visceral chamber itself below the thick-
ened portions of the tubes ; and the only traces of these organs
are to be found in the tooth-like projections of the margins of
the calices. These projections are generally three in number
— two on one margin, and a single unpaired tooth opposite the
notch between these on the opposite margin ; but there may be
five of these teeth — three on one margin, and two on the other.
The tabulae present no specially noticeable features, being well
developed and complete, though not very numerous, through-
out the central unthickened portion of the tubes. The differ-
ent species of Ccenites will require careful revision, by the light
of microscopic sections, before they can be regarded as fully
established.

In its geological range, the genus is principally Upper
Silurian ; but species supposed to belong to it have been also
described from the Devonian formation. In the Upper Silurian
rocks the genus is found in Britain, Europe, and North America.
The species which I have selected as illustrative of the genus
are Ccenites jtmtperinus, Eichw., and a form which I believe to
be the Ccenites linearis of Edwards and Haime.

134 TABULATE CORALS.

CcBnites juniperinus, Eichwald.

(PI. VI, figs. 5, 5 h).

Coenites juniperinus, Eichwald, Zool. Spec, vol. i. p. 179, 1829.

Limaria clathrata, Lonsdale, in Murchison's Sil. Syst., p. 692, PI. XVI, bis,

figs. 7, 7 a, 1839.
Cmiites juniperiims, Milne-Edwards and Haime, Pol. Foss. des Terr. Pal,

p. 301, 1851 ; and Brit. Foss. Corals, p. 276, PI. LXV., figs. 4 and 4 a.
(Compare Limaria ramulosa, Hall, Pal. N.Y., vol. ii. p. 142, PI. XXXIX.,

fig. 4, 1852.)

Spec. Char. — Corallum dendroid, of cylindrical dichotomous-
ly-dividing branches, the diameter of which is generally about
two lines. Corallites nearly vertical in the centre of the
branches, with thin walls, and about one-sixth of a line in
diameter ; gradually diverging in their upward course till they
reach a point from one quarter to half a line from the surface,
when they suddenly bend outwards, their walls being now
greatly thickened, and the visceral chamber reduced to a mere
slit. Calices fissure-like and elongated in the direction of the
transverse diameter of the branches, their long diameter about
one-third of a line ; the lower margin adorned with two pro-
minent teeth, while the upper margin carries a single tooth cor-
responding in position to the notch between the lower teeth.
Tabulae not very numerous, but well developed and complete.
Mural pores moderately numerous, circular, not excessively
large, irregularly distributed.

Ql)s, — This well-known Upper Silurian form is readily dis-
tinguished by the external characters of the cylindrical branches,
and the long, transversely-disposed toothed calices (PI. VI.,
fig. 5), which are not elevated above the general surface. The
fissure-like calices are generally separated from one another, in
a vertical direction, by interspaces varying from about one-fifth
to one-third of a line ; and they thus appear as if sunk in a
compact smooth coenenchyma. In longitudinal sections (PI.
VI., fig. 5 a) this apparent coenenchyma is shown to be due to
a deposit of sclerenchyma within the tube of each corallite in

GENERA OF FAVOSITID^. 135

the neighbourhood of its mouth, this portion of the coraHite
being in reality rather dilated than narrowed. The deposit of
secondary sclerenchyma seems, further, to be laid down almost
entirely on the upper aspect of each corallite in its interior, so
that the visceral chamber is reduced to a mere slit occupying
the lower side of the corallite. In the interior portions of the
branches the corallites are not thickened, but possess patulous
tube-cavities (PI. VI., fig. 5 a), which are Intersected by remote
and complete tabulae, and are placed in communication by dis-
tinct mural pores. Transverse sections (PI. VI., fig. 5 6) not
only show the absence of secondary thickening in the walls
of the corallites in the interior of the corallum, but likewise
the compressed and subpolygonal form of the tubes in this
region.

Formation and Locality. — Abundant in the Wenlock Lime-
stone of Dormington Quarry, Stoke-Edith.

Coenites linearis, Edwards and Haime.

(PI. VII., figs, i-i e.)

Cceiiites linearis, Milne-Edwards and Haime, Pol. Foss. des Terr. Pal., p. 302,
1851 ; and Brit. Foss. Cor., p. 277, PL LXV., fig. 3, 1854.

Spec. Char. — Corallum usually in the form of a lamellar ex-
pansion, sometimes sublobate, rarely massive. Corallites from
a fifth to a fourth of a line in diameter, compressed, and pos-
sessing thin walls throughout the interior of the corallum. On
approaching the surface they bend more or less abruptly out-
wards, their upper walls being now greatly thickened by an
adventitious deposit of sclerenchyma, and their tube-cavities
reduced to a mere fissure. Calices in the form of long linear
slits, sometimes nearly straight, sometimes arcuate, which have
a length of about half a line, or rather less, with a width of not
more than about one-twelfth of a line. Tabulae remote, hori-
zontal, complete. Mural pores circular, of tolerably large size,
moderately numerous, irregularly distributed. Septa repre-

136 TABULATE CORALS.

sented by from three to five longitudinal ridges, which appear
to be confined to the thickened outer portions of the tubes, and
which form a corresponding number of teeth projecting into the
calice. Ordinarily there are two of these teeth on one lip of
the calice, and one on the other ; but there may be three teeth
on one lip and two on the other, or even more of these projec-
tions may be present.

Obs. — I have some doubt as to the propriety of identifying
my specimens with Coenites linearis, E. and H., which is de-
fined as follows (Brit. Foss. Con, p. 277) : —

" Corallum massive, convex, or subgibbose, and composed of
thin superposed layers. Calices closely set, not prominent, or
but very slightly so, linear, with their margin very obscurely
denticulated, about half a line broad, and one-twelfth in the
contrary direction."

My specimens agree with the above description in the linear
form of the calices, and in the dimensions of these apertures ;
but the calicine teeth are very well marked (in well-preserved
examples), and the corallum, though sometimes sublobate,
could certainly not be properly said to be ** massive." The
great majority of the specimens which I refer here have the
form of thin lamellar or palmate expansions (PI. VII., fig. i),
two inches or more in width, with a thickness of a line and a
half to two lines. The corallites in the centre of the frond are
nearly or quite parallel with the flat surfaces of the latter, and
they diverge outwards to open either on one surface only, or
apparently more generally upon both surfaces. Sometimes, by
the superposition of several laminae, the corallum may attain a
thickness of four or five lines ; and the same dimensions are
sometimes reached when the corallum has the form of a broad
flattened or palmate stem. I have never seen any truly mas-
sive example. Upon the whole, however, considering the points
of likeness between the two, I think it safest to refer my
specimens to C. linearis, E. and H., and to regard the speci-
men described by Edwards and Haime as probably excep-

GENERA OF FAVOSITID^. 137

tlonal, or as owing its apparently massive form merely to the
coalescence of a succession of crusts.

The calices of C. linearis, E. and H., are very characteristic.
They appear as long linear slits (PI. VII., figs, i-i b), which
may be nearly straight, but are more commonly strongly curved,
and which have their margins toothed by a variable number of
septa (most generally two on one margin, and one on the other),
while they have the appearance of being embedded in a dense
compact ccenenchyma. The form of the calices accurately
expresses the form of the visceral chamber to a certain depth
(half a line to nearly one line) below the surface, and tangential
sections taken within this depth (PI. VII., fig. i c) show that
the tubes are still curved linear fissures, with denticulate mar-
gins, and surrounded by dense calcareous tissue. In the in-
terior of the corallum, on the other hand, the corallites appear
as thin-walled, subpolygonal, compressed tubes, with freely
open cavities. The internal structure, in fact, is precisely the
same as that already described as characterising C. juniper inus,
Eichw. Thus, sections taken at right angles to the flat surfaces
of the frond (PI. VII., fig. i d) show that the gently-diverging
and thin-walled tubes of the central area, on approaching a
point situated a line or less below the actual surface, suddenly
bend outwards, nearly at right angles to their former course.
They now dilate, but their central cavity, instead of under-
going a corresponding expansion, becomes now still further
restricted, and is reduced to a narrow linear chamber, which
occupies one side of the corallite, the whole of the remaining
space within the walls of the latter being occupied by a dense
secondary deposit of sclerenchyma. There is, however, no
true " ccenenchyma ; " and the appearance of such a structure
is only due to the deposition of this sclerenchyma in the
interior of the tubes, and its coalescence in contiguous coral-
lites, to the more or less complete obliteration of the walls of
the latter as recognisable structures. Lastly, sections taken
through the median plane of the frond, and parallel with its

138 TABULATE CORALS.

flat surfaces (PL VII., fig. i c), show the visceral chambers of
the (here) thin-walled tubes to be crossed by remote and com-
plete tabulae, and to be connected by a well-developed system
of circular mural pores.

Fomnation and Locality. — Not uncommon In the Wenlock
Limestone of Benthall Edge, Longhope, Dudley, and Stoke-
Edith.

'39

CHAPTER V.

GENERA OF FAVOSITIDzE — {cOJltinUed).

Gams MiCHELiNiA, De Koninck, 1842.
(An. foss. des terr. Carb. de le Belgique, p. 29.)

Gen. Char. — Corallum forming hemispherical, depressed, or
pyriform masses, often of considerable size, composed of pris-
matic or subcylindrical corallites, in close contact throughout
their entire length. Walls not thickened to any unusual extent,
perforated by numerous mural pores, which are often multi-
serial, and have no definite arrangement. Calices polygonal or
subcylindrical, not surrounded by thickened margins. Tabulae
numerous, generally more or less curved with their convexities
upwards ; usually anastomosing with one another to a greater
or less extent, so as to give rise to a loose and open vesicular
tissue; and often carrying numerous vertically-directed spin-
ules. Septa represented by numerous radiately - arranged
longitudinal striae, ridges, or vertical rows of tubercles, varying
in number from twenty-five to forty. Under surface covered
by a concentrically-striated epitheca, which may or may not be
provided with hollow radiciform prolongations.

Obs. — This well - known genus comprises a number of
Devonian and Carboniferous corals, which present a close
general resemblance to the larger forms of Favosites. The
corallum (fig. 21) is massive, usually more or less hemispheri-

140

TABULATE CORALS.

cal, or in the form of a flattened expansion, the under surface
of which is covered with a wrinkled epitheca. The corallum is
attached to some foreign body by the centre of its base, and

in some instances
the epitheca gives
off root - like pro-
loncrations in addi-
tion. In all the typi-
cal forms the coral-
lites are polygonal,
of larger size than
in the ordinary spe-
cies of Favosites,
and in close contact
throughout their en-
Fig. 2\.—MicheIimacoiivcxa, D'Orb., viewed from above, tire length; and they
of the natural size, from the Corniferous Limestone of ,. ^ ,1

Ontario. (After Billings.) radiate from the Cen-

tre of the base, those
occupying the circumference of the mass being so highly in-
clined as to be nearly parallel with the epitheca, while those
in the middle are more or less nearly vertical. The visceral
chamber, like the corallite itself, is usually polygonal ; but in
some cases {e.g., M. cylindrica, E. and H.), the tube-cavity
is constricted at intervals by ring-like ridges, which give it
a cylindrical appearance. The walls, though moderately stout,
have none of the secondary thickening of the interior so
characteristic oi Pachypora, Lindst., and its allies. The mu-
ral pores are numerous, circular, of variable size, and quite
irregular in their distribution. The chief noticeable feature
about the tabulae is their marked curvature, their convexities
being directed upwards. Moreover, the tabulae seldom extend
quite across the visceral tube, but in approaching the margin,
they usually unite with other smaller tabulae, so as to give rise
to the formation of numerous large-sized lenticular vesicles,
which are most abundantly developed near the sides of the
tubes. The extent, also, to which the tabulae thus become

GENERA OF FA VOSITID^E. 141

vesicular varies in different species of the genus ; and the con-
dition of these structures is in any case very different to that
which obtains in Favosites {Evimonsia) heinispherica, Yand. and
Shum., where the tabulae are mostly actually " incomplete," and
do not become united with contiguous plates. The tabulae
often carry on their upper surface vertically-directed spinules,
which may be regarded as a continuation towards the centre of
the marginal septa. These latter are in the form of vertical
striae, or ridges, or rows of tubercles ; and their number varies
from twenty-five to fifty.

It will be evident from the above description that Michelinia
is a true Favositoid coral, very nearly allied to Favosites itself,
near which it has been almost uniformly placed by palaeontolo-
gists. It does not, in fact, differ from Favosites proper in any
characters except that the tabulae usually subdivide and become
more or less united among themselves, while the septa are
more numerous, and are not spiniform, and the mural pores
are irregularly distributed. Of these peculiarities the subvesi-
cular character of the tabulae is the only one of generic import-
ance, and even this is not equally noticeable in all the species.
The occasional presence (as in M. favosa, Goldf.) of radiciform
prolongations from the lower surface — apart from the fact of
the total absence of these structures in most of the species —
cannot, in my opinion, be regarded as sufficient to overbalance
the many and weighty resemblances between this genus and
Favosites. I am therefore altogether unable to agree with my
friend Dr Lindstrom in thinking that Michelinia should be
removed from the Favositidce and placed in the family of the
CystiphyllidcE (On the Affinities of the Antkozoa Tabulata^
Ann. and Mag. Nat. Hist, sen 4, vol. xviii. p. 12).

I shall in the meanwhile, for reasons to be stated imme-
diately, retain Plettrodictyum, Goldf, and C/i07iostegites, E.
and H. (= HaimcophylliLm, Bill.), as generically distinct from
Michelinia, though I think that the first of these, at any rate,
will ultimately have to be united with the present genus. If
this course be followed, then the genus Michelinia is only

142 TABULATE CORALS.

known with certainty from the Devonian and Carboniferous
rocks ; since the forms which have been noted as occurring in
the Upper Silurian deposits of North America appear to be
small discoid examples of the type of Pleiwodictytim. My own
collection includes excellently-preserved specimens of M. con-
vexa, D'Orb., M. favosoidea, Bill., and M. (Einmonsid) cylm-
drica, E. and H. ; but as these are not only silicified, but have
their tubes entirely empty, they do not admit of being satisfac-
torily sectioned for the microscope. Through the kindness of
Mr Etheridge, I have also had the opportunity of examining
specimens of M. inegastonm, Phill, AI. tenuisepta, Phill., and
M. favosa, Goldf , from the Museum of Practical Geology.
As, however, I am not in the position of being able to give any
details as to the microscopic structure of any of the above, it
will be unnecessary to select any species for description.

Gcmis Pleurodictyum, Goldfuss, 1829.
(Petref. Germ., t. i. p. 113.)

Gen. Char. — Corallum discoidal, with a slightly convex
upper surface, attached to foreign bodies by the centre of its
base, and having its lower surface covered by a well-developed,
concentrically-striated epitheca. Corallites diverging from the
centre of the base, those on the circumference being nearly
horizontal, while the median ones are more or less nearly per-
pendicular ; their general shape polygonal or subcylindrical.
Walls of considerable thickness, pierced from side to side by
mural pores, which have no regular arrangement. Tabulae not
very numerous, nor markedly arched ; often inosculating to
some extent, but not giving rise to a vesicular or subvesicular
tissue. Septa rudimentary, in the form of marginal ridges or
rows of vertically-disposed spines.

Obs. — This genus was founded for the reception of the
curious P. problematicum of the Devonian deposits, which is
still only known by means of casts of the tubes in sandstone.

GENERA OF FA VOSITIDyF. 143

The structure of these casts was well described by Edwards
and Haime (Pol. Foss. des Terr. Pal., p. 209), and the true
significance of the most singular of the features presented by
the genus was fully recognised by them. They placed the
genus, however, in the Perforate Zoantharia, in the immediate
neighbourhood of ProtarcEa and Litharcsa, and thus failed to
appreciate its relationships with the Favositidcs. Dr Rominger
was, I believe, the first to point out (Amen Journ. Sci. and
Arts, vol. XXXV. p. 82, 1863) that Pleiirodictyiun was really
founded upon casts of a coral allied to Favosites or Michelbiia ;
and he has recently united it with the latter genus (Foss. Corals
of Michigan, p. 72, 1876). At present, we are acquainted with
the actual corallum itself in more than one species of Pletiro-
dictytmi; and I shall defer any further^remarks upon the genus
till I have described the only one of these which I have had
the opportunity of examining with proper fulness,

Pleurodictyum stylophorum, Eaton.

(Fig. 22, and PI. VIIL, figs. \ - \ b.)

Astraa sfylophora, Eaton (?), Geological Text-Book, 1832.

Fkui'odicfyum Americamim, Ferd. Roemer, Lethaea Pal^eozoica, PI. XXIII ,

figs. 2 a and 2 b, 1876.
Michclinia trochiscus, Rominger, Fossil Corals of Michigan, p. 75, 1876.

Spec. Char. — Corallum discoidal, with a slightly convex
upper surface, generally from an inch to an inch and a half in
diameter, and about half an inch or rather more in height ;
attached by the centre of the base to some foreign body such
as the stem of a Crinoid. Lower surface covered by a well-
developed epitheca, with strong concentric wrinkles, and also
with finer radiating strice. Corallites subpolygonal, very un-
equal in size, the larger ones from nearly two lines to about
three lines in diameter. Walls thick, perforated by irregularly-
placed mural pores. Septa in the form of from twenty-five to
thirty-five or more marginal ridges or vertical rows of blunt
spines. Tabulae few in number, slightly convex or horizontal,

144 TABULATE CORALS.

sometimes uniting with one another, but not subvesicular in
character. The "vermiform body" of Pleurodictyitjn pro-
blematiatm, Goldf., is sometimes (always ?) present in the
interior of the corallum.

Obs. — This pretty Httle species seems to have been first
named Astrcsa stylophora by Eaton, I presume in his ' Geolo-
gical Text-Book' (published in 1832); though I am unable to
consult this work, and cannot speak positively upon this point.
Dr Rominger {loc. cit.), in describing his Michelinia ti^ochiscus^
gives the above as its synonym ; and assuming the correctness
of this, it would seem that Eaton's specific name has the clear
right to be retained, as no other species of Michelinia or Pleuro-
dictywn has been similarly entitled. Should it be found neces-
sary, for any reason, to abandon Eaton's name, then it would
be a question whether the present species should not stand as
Plezirodictyum Aniericanum, under which name it was well
figured and briefly described by Professor Ferd. Roemer in
1876 (Leth. Pal, PI. XXIII., figs. 2 a, 2 b). Through the kind-
ness of my friend Mr George Jennings Hinde, I possess a few
specimens of this remarkable form, which is of special interest
as presenting us with the actual corallum of a form unques-
tionably congeneric with Pleurodictywn problematicum, Goldf.,
though apparently specifically distinct. These I have sub-
mitted to a careful examination by means of thin sections,
and I shall now give the principal results of this, along with
some remarks upon the genus Pleurodictyum^ and upon P.
problematictmi, Goldf.

As before remarked, P. problematicum is only known by
casts in sandstone, which are of not very rare occurrence in the
Devonian deposits of Europe and of Devonshire. Precisely
similar casts — though probably specifically distinct — occur in
the Onondaga sandstones of North America, and have been
well described and figured by Meek and Worthen, with a
somewhat doubtful reference of them to the European species
(Geol. of Illinois, vol. iii. p. 405, PL IX., figs, i a-\ c, 1868).
In both these cases the fossil (fig. 22, a and b) consists of a

GENERA OF FA VOSITIDJE.

145

series of prismatic or subcylindrlcal columns radiating from a
common base, In such a manner that those nearest the peri-
phery are horizontal or even reclined, and those in the centre
are vertical, while intermediate columns have correspondingly
intermediate grades of inclination. These columns are some-
times markedly striated with longitudinal ridges, as well as
marked with small rounded elevations (fig. 22, b) ; while each is

. 22. — A, Lower surface of the cast of Pleiirodictyiivi p7-ohlcmaticu7n, Goldf., from the Lower
Devonian of Germany, of the natural size (after Roemer), showing the vermiform body in
the centre ; B, A few of the separate casts of the tubes of Fkurodictyum problanaticiim,
Goldf., from the Devonian of the Eifel, showing the casts of the mural pores and inter-
septal grooves, enlarged (after Milne-Edwards and Haime) ; C, Upper surface of the coral-
lum of Pleurodktyum stylophurujn, Eaton, from the Hamilton group of North America, of
the natural size, showing the form of the calices (original) ; D, Lower surface of another
example of the same, of the natural size, showing the striated epitheca, and the point
where the corallum was attached to the stem of a Crinoid (original).

connected with its neighbours by a number ol cylindrical rods.
The above appearances are now readily Intelligible, as, indeed,
they were to all intents and purposes even to the authors of the
' Polypiers fossiles,' though these distinguished observers had
never seen any actual coral capable of giving rise to a similar
cast. The prismatic columns of P. probleniaticttm are, then,
casts of the polygonal corallites of a Favositold corallum, of a

K

146 TABULATE CORALS.

discoidal form ; the rounded tubercles which they carry upon
their surface, as well as the rods which connect contiguous
columns, are casts of the mural pores, left by the solution of the
thick walls ; and the vertical ridges (not always present) are
casts of the grooves between the septal ridges or striae. More-
over, perfect examples of P. problematicuin show that the cor-
allum was concavo-convex, its under surface being concave
(probably a character of specific value), and covered by a con-
centrically-striated epithecal membrane. So far there is no
difficulty in interpreting the peculiarities of the P. problemati-
cum of the European Devonian by the light afforded by the
well-preserved coralla of allied forms in the corresponding forma-
tion in North America ; but there remain two points of difficult
interpretation. One of these points consists in the occasional
existence of numerous small pits — much more numerous than
the corallites themselves — on the upper surface of the cast of
the epitheca (see Pol. Foss. des Terr. Pal., PI. XVIII., figs. 4
and 4 a). Messrs Meek and Worthen have not only noticed
the same phenomenon in the American specimens, which they
provisionally refer to P. problematiczLm, Goldf. ; but they notice,
in addition, that the corallites which rest directly upon the
epitheca are connected with the latter by rods precisely similar
to those which unite the different corallites with one another.
They suggest that this indicates the occurrence of " pores "
passing through the base ; but it may be offered as a probable
explanation that these really indicate the existence in this
particular species of numerous radiciform and hollow pro-
longations of the lower surface of the epitheca, such as
are known to occur in Michelmia favosa, Goldf, and which,
after all, are essentially of the same nature as the "mural
pores."

The other point of difficulty consists in the presence in many
(but apparently not in all) specimens of P. problematicum,
Goldf, of the curious structure known as the "vermiform
body." This body (fig. 22, a) has the form of a cylindrical,
crooked, often S -shaped rod, occupying the centre of the base

GENERA OF FAVOSITID^. 147

of the coralliim, and havinof the coralHtes radiatlnor from it on
all sides. None of the American examples referred to this
species by Meek and Worthen {loc, cit.) show any traces of
this structure. The nature of this curious body has been much
disputed, but it has generally been regarded as being one of
two things — viz., either the cast of the burrow of some boring
Annelide which mined the coral after the latter had attained
its full growth, or else the calcareous tube of some Annelidous
genus like the existing Serpzda, to which the coral attached
itself when young, and which it subsequently enveloped in the
process of development. This latter view, which would make
the phenomenon an instance of " commensalism," is the one
which was adopted by Edwards and Haime, and in which they
have been followed by most subsequent writers. It is a note-
worthy fact, however, that a tube of precisely the same nature
has been found by me to exist in the only specimens of P. sty-
lopJwrum, Eaton, which I have been able to section for the
microscope ; and though I do not pretend to offer any satis-
factory explanation as to its true significance, I have been able
to satisfy myself of the following points, which have a consider-
able bearing upon any view which may be framed upon this
subject : —

1. The mere fact of the occurrence of this peculiar structure
in two different species of the same genus, in regions as widely
remote as Europe and North America, is prima facie, though
by no means conclusive, evidence against the view that the
" vermiform body " is merely the work of a parasite, or is the
tube of an Annelide upon which the corallum grew.

2. The " vermiform body " in P. stylophormn, Eaton, either
existed before the coral, or grew simultaneously with it. This
is shown incontrovertibly by the fact that, in sections, the coral-
Htes are seen to accommodate their shape to that of the t7t.be, and
to be fixed to it in places by their bases. In no instance ob-
served by me does the tube cut across the corallites (see
PI. VIII., figs. I - I b, where the tube is shown in section).
This observation is sufficient to conclusively negative the view

148 TABULATE CORALS.

that the tube can be the work of some parasitic animal which
bored into the coral after the latter was formed.

3. The tube was by no means confined to the mere base of
the coral, nor did it lie like the letter S in a single plane. On
the contrary, it traversed the corallum in a loose and open
spiral, so that both vertical and horizontal sections cut it at
various points (see PI. VIII., figs, i-i b).

4. The tube (in adult specimens, at any rate) was completely
concealed within the corallum, and was, to all appearance, alto-
gether superior to the epitheca. Whether or not it had any
opening upon the tipper surface of the corallum, I cannot say.^

5. The walls of the tube are extremely thin, calcareous, and
apparently destitute of any definite structure. The interior is
usually filled with transparent calcite, but occasionally there are
seen inside it numerous spheroidal or ovoid opaque bodies, as
to the nature of which I can offer no opinion whatever (PI.
VIII., fig. \ ci). It will be seen from the above that this
peculiar structure is one well worthy of further examination
by those who may have calcareous specimens suitable for the
preparation of microscopic sections. My own observations are
much too limited to enable me to come to any definite conclu-
sions as to its true nature ; but they are at the same time suffi-
cient to make me dubious as to the received explanations upon
this subject.

Returning now to P. stylophortim, Eaton, I may give a brief
account of its structure, as shown by microscopic sections, it
being the only species of Pleurodictyuin which, to my know-
ledge, has ever been examined by this method. The general
form of the corallum, as seen in fig. 22, c and d, is that of a
small discoid expansion, the upper surface of which carries the
calices, and is more or less convex ; while the lower surface is
generally flat or slightly convex, and is covered by a strong

^ Dr Rominger (Amer. Journ. Sci. and Arts, vol. xxxv. p. 82), however, states
that he has observed specimens in which the vermiform tube opens upon the upper
surface of the corallum by a round mouth. His further statement that the tube
traverses the substance of the corallum irrespective of the direction of the corallites
through which it seems to cut, is not borne out by my specimens.

GENERA OF FA VOSITID^.

149

epitheca, marked with concentric and radiating striae. All my
specimens show a distinct cicatrix of attachment, the foreign
body upon which the coral grew being in one instance unques-
tionably the column of a Crinoid (fig. 22, d). I can also detect
no traces of perforations nor of radiciform prolongations of the
epitheca. The upper surface (fig. 22, c) shows the apertures
of the polygonal, irregularly-sized corallites. Tangential sec-
tions, taken just below the upper surface (PI. VIII., fig. i a),
cut across the corallites at right angles, and show that the
polygonal tubes are surrounded by thick walls, those of con-
tiguous corallites remaining so far distinct as to be always
separated from one another by a marked and definite line of
demarcation. The same feature is shown by sections which
cut the corallites longitudinally (PI. VIII., figs, i and i 6).
Both these kinds of sec-
tions exhibit, further, the
well -developed but irreg-
ularly-distributed " mural
pores," together with cer-
tain other openings of a
seemingly different nature,
the structure of which I
shall endeavour to eluci-
date by the help of the an-
nexed diagram. Remem-
bering that the mural pores
are apertures which pass
through the walls of the
corallites from side to side,
it is easy to see how and
under what forms they may
present themselves in thin
sections of the corallum of
any of the Favositidcs. In

transverse sections (fig. 23, a and c) the pores are usually
not to be detected, or only here and there, and they present

Fig. 23. — Semi-diagrammatic representations of
sections of the corallum of Favosites and Pleuro-
dictyum, showing "mural pores" and "intra-
mural canals," the former shaded black, the
latter left unshaded. A and B, Transverse and
vertical sections of Favosites, showing mural
pores only; c and D, Transverse and vertical
sections of Pleurodictyuvi, showing mural pores
and intramural canals.

15°

TABULATE CORALS.

themselves as canals which run right across the walls of
two contiguous corallltes, and place their visceral chambers
in direct communication. In vertical sections (fig. 23, b and d),
on the other hand, the mural pores may present themselves
under one or other of two forms, or under both of these.
Thus they may appear either as canals running directly across
the wall between two contiguous tubes, or (if the section hap-
pen to coincide more or less nearly with the plane of one of
the walls) as scattered circular pores situated within the space
bounded by the lateral walls of the corallites. All the Favosi-
tidce may show the phenomena just described ; but in Plettro-
dictyum and some other types thin sections show the existence
of another set of canals, which appear to run entirely within the
substance of the walls, and to have a course parallel with the
flat surfaces of the latter. The canals in question are best
seen in transverse sections (fig. 23, c), where they are shown
as distinctly circumscribed circular openings, placed at the
point of union of the walls of two contiguous corallites, or
situated within the actual substance of the wall. Similar open-
ings are seen in long sections (fig. 23, d), but the evidence is
here not so satisfactory as in the preceding case, since we
might be dealing with mural pores passing through the angles
of the prismatic corallites. What these canals are, it is difficult
to say, but they are certainly distinct from the " mural pores ; "
and as it is convenient to have a distinct name for them, I shall
call them the " intramural canals." Possibly they may only
be due to imperfect calcification or coalescence of the walls of
the corallites ; but that they are distinct from the mural pores
is shown by the fact of their occurrence in forms like Lyopora,
Nich. and Eth. jun., in which these latter openings are not
known to occur. In Pleurodictyum the " intramural canals,"
as just defined, are neither numerous nor very conspicuous.
They are, however, present in a marked form in Colunmopora,
Nich., and in Lyopora, Nich. and Eth. jun., in both of which
they appear to have been regarded as " coenenchymal tubules ;"
though their sparse and scattered arrangement, and their total

GENERA OF FAVOSITIDyE. 151

absence in parts of the corallum, together with the fact that
they traverse the walls in different directions, would entirely
negative this view.

The only remaining points in the anatomy of Pleurodictyum
stylophortLnt which need notice, concern the condition of the
septa and tabulae. Returning again to transverse or tangential
sections of this species (PI. VIII., fig. i a), we find the septa
represented by short spines arranged in vertical rows, quite
resembling the same structures in various species of Favosites.
The tabulae are seen in long sections (PI. VIII., figs, i and i b)
to be always well developed, and to have the form of strong
horizontal flexuous plates, which are not strongly convex, and
which do not give rise to anything that could be appropriately
called " vesicular tissue," though they not uncommonly unite
with one another to a limited extent. Owing" to the shortness
of the corallites, there are usually not more than four or five
tabulae in a single tube.

Upon the whole, it will be seen by the preceding description
that there is a close relationship between Pleurodictyum, Goldf ,
and Micheliiiia, De Kon., and it is a matter of question if the
two genera can be kept apart. Should it be found necessary to
merge these two genera, it is Mickelinia which will have to
give way to the older Plcitrodidyiun, and not, as some writers
assume, the latter to the former. In the meanwhile, however,
I think it safest to keep the two distinct until, at any rate, the
structure of Pleurodictyum has been fully worked out. If this
course be followed, Pleurodictyzim, Goldf., will contain corals
in most respects quite similar to Mickelinia, De Kon., but dis-
tinguished by their small size and discoid form, and by the fact
that the tabulae are not markedly convex, and do not subdivide
or inosculate to any notable degree. It is possible (though not
likely) that the " intramural canals " which I have described
as occurring in Pleurodictyum may be found to distinguish the
genus further from Mickelinia. I need only add that it is
certain that Dr Ferd. Roemer must have been misled by
appearances when he asserts (Leth. Pal, Explanation of PI.

152

TABULATE CORALS.

XXIII., 1876) that there are no tabulae in Pleurodictyum, these
structures being quite as well developed as could be expected
in such short tubes.

Formation and Locality. — Hamilton group (Devonian),
Hamburg, State of New York, Coll. George J. Hinde, (Judg-
ing from the figures, it would seem not improbable that the
coral described by Prof. Ferd. Roemer in the * Silurian Fauna
of West Tennessee,' p. 19, i860, under the name of Calamopora
Forbesi, var. discoidea, may be really a species of Pleurodictyuni
allied to P. stylophoruni, Eaton. It is probable, also, that the
nummiform species of Alickelinia alluded to by Dr Rominger
in the ' Foss. Corals of Michigan/ p. 72, as occurring in the
Upper Silurian strata of North America, are referable to
Pletcrodictyum, if the latter genus is to be kept distinct.)

Genus Chonostegites, Edwards and Haime, 185 1.

(Pol. Foss. des Terr. Pal., p. 299.)

Haimeophyllum, Billings, Canad. Journ., new sen, vol. iv. p. 139, 1859.

Gen. Char. — Corallum forming large subhemispherical, sub-
fasciculate masses, composed of cylindrical corallites, which grow
side by side, and are annulated by numerous close-set, hollow,
periodic expansions, which alternate with as many circular con-
strictions. For the most part the corallites are separate, except
that they are united by the periodic expansions above spoken
of, which thus form a succession of concentric floors, connecting
the tubes with one another. In the parts between these periodic
floors the corallites are enclosed each by a distinct epitheca, and
the walls are imperforate. There are, however, often parts of
the corallum in which the walls of contiguous corallites are in
close contact, and then numerous " mural pores " are developed.
Tabulae numerous, arched, often uniting with one another in
such a way as to give rise to a loose and open subvesicular
tissue, which is continued into the hollow periodic expansions
of the corallites. Septa in the form of short spines in the in-

GENERA OF FAVOSITIDM. 153

terlor of the tubes. New corallites produced by gemmation
from the hollow periodic expansions in the intervals between
the old cups.

Obs. — It is perhaps impossible for any one who has not
access to the original examples of Chonostegites Clappi, E. and
H., and Michelinia intei^mittens, Bill., to entirely and finally
unravel the confusion in which the present genus is enveloped.
I shall, however, briefly state the conclusions at which I have
arrived upon this subject, and some of which I regard as quite
certain.

The genus Chonostegites was founded by Milne-Edwards and
Haime for the reception of a coral unquestionably possessing
the general characters given in the above generic diagnosis,
which is based upon specimens of the coral described by Billings
under the name of Hawieophyllum inordinatum. They state
that their specimens are of Devonian age, and that they were
found in the drift of Dayton in Ohio. Under these circum-
stances it cannot be doubted but that the original specimens of
Chonostegites Clappi^ E. and H., were derived from the Corni-
ferous Limestone, the silicified corals of this formation beingf
abundantly distributed in the drift of various parts of the
Northern United States.

At a later date, in 1859, Mr Billings described two corals
from the Corniferous Limestone of Canada, under the names of
Michelinia intermittens and Haimeophylhwi inordinatum^ the
latter being made the type of a new genus. With regard to
Michelinia intermittens, Mr Billings himself expresses a doubt
if it be truly separable from Chonostegites Clappi, E. and H.,
adding that in this case the species should stand as Michelinia
Clappi. This opinion on the part of Mr Billings was based
upon the observation that in those portions of the corallum of
M. intermittens in which the corallites are in contact they are
prismatic in shape, and that they possess mural pores. On the
other hand, Haimeophyllum is founded for a coral which is said
to differ from Michelinia only in the fact that the corallites are
not in close contact, are subparallel, and are united by the coal-

154 TABULATE CORALS.

escence of periodic expansions of the margins of the caHces,
while mural pores are alleged to be absent.

At a still later date, in 1876, Dr Rominger (Foss. Cor. of
Michigan) placed Chonostcgites Clappi, E. and H., mMichclinia,
and referred Ulichelinia intermittens, Bill., in part to the same
species ; while he considered M, intermittens as also in part
synonymous with ]\I. [Emmonsia) cylindrica, E. and H.

Having carefully examined an excellently-preserved series of
specimens oi Haiineophyllum inoi'dinattim, Bill., I have failed
to discover any character by which it could be specifically
separated from Chonostegites Clappi, E. and H. Mr Billings
was undoubtedly in error in supposing that " mural pores " are
absent in Haimeop/iylhun, these openings being present in all
parts of the corallum where the tubes come into actual contact.
I regard Haimeophyllum, Bill., therefore, as a synonym of
Chonostcgites, E. and H., and shall discuss the relations of the
latter to Michelinia, De Kon., later on.

In the second place, I think Michelinia intermittens, Bill., to
be merely a variety of Haimeophyllum ordinatiim, Bill., with
the tubes more extensively in contact than is usual in this
variable species. As the latter species is in my opinion the
same as Chonostegites Clappi, E. and H., it follows that M. in-
terniittens, Bill., is a synonym of C Clappi, as it is in part made
to be by Dr Rominger. I need only add that there cannot be
the slightest hesitation in rejecting Dr Rominger's further view
thatil/. intermittens, Bill., is in pai^t identical with^. cylindrica,
E. and H., since Billings expressly states that his species was
founded upon a single specimen ; and it cannot, therefore, pos-
sibly be partly referable to one species and partly to another.

Before discussing the relations between Chonostegites and
Michelinia, and the possible propriety of uniting them with one
another, it will be well to briefly describe the structure of C.
Clappi, the type and the only satisfactorily differentiated species
of the former genus.

GENERA OF FAVOSITIDvE. 155

Chonostegites Clappi, Edwards and Haime.

(PI. VIII., figs. 2-2 0.)

Chonosicgitcs Clappi, Milne-Edwards and Haime, Pol. Foss. des Terr. Pal.,

p. 299, 1851.
Michelinia intermittens, Billings, Canad. Journ., new ser., vol. iv. p. 113, 1859.
Haimeophyllujn inordinatum, Billings, Canad. Journ., new ser., vol. iv. p.

139, fig. 29, 1859. ^
Miche/inia Clappi, Rominger, Foss. Cor. of Michigan, p. 75, PI. XXVIII.,

figs. 3 and 4, 1876.

Spec. Char. — Corallum often of considerable size, composed
of subparallel, essentially circular, tubular corallites, which are
for the most part free, though sometimes partially In contact,
in which latter case they become more or less polygonal by
mutual pressure. In parts where they are in contact the walls
of the corallites are perforated by numerous Irregularly-distri-
buted mural pores, which place the visceral chambers of con-
tiguous tubes in direct communication. When they are not in
contact, the corallites are individually enclosed in a distinct
epitheca, which Is not perforated, and which is marked with
numerous fine encircling striae. Where not in contact, also,
the corallites are annulated by numerous alternate constrictions
and dilatations, giving to each the appearance of a succession
of funnels vertically superimposed upon one another. The
dilatations of contiguous tubes are placed more or less at the
same levels, and unite with one another, so as to form a succes-
sion of concentrically superposed floors, which can be shown to
be hollow, and thus to place the visceral chambers of neigh-
bouring tubes In actual communication. Viewed from above,
the calices are seen to be circular, and to be surrounded at a
little distance by faintly-marked polygons inscribed on the
upper surface of the connecting-floors. Tabulae numerous,
arched, inosculating to a greater or less extent, and forming
large lenticular cells, which are continued into the hollow hori-
zontal connecting-floors. Septa in the form of short spines
arranged In vertical rows. The upper surfaces of the tabulae

156 TABULATE CORALS.

are also often serrated with erect spinules, which appear to
represent continuations of the septa towards the axis of the
visceral chamber. New corallites budded forth between the
old calices from the hollow connecting-floors.

The dimensions of the corallites, the degree to which they
are in contact, and the closeness of the periodical expansions,
vary in different examples. In the most typical forms, the
tubes themselves are about two lines in diameter, but the
diameters of the polygons inscribed round these upon the upper
surfaces of the horizontal floors (where recognisable) are three
lines or more. In other examples the tubes themselves may
reach three lines or over in diameter. The periodical expan-
sions which give rise to the horizontal floors by their union are
mostly from one line to a line and a half distant from one
another, but they may be two or even three lines apart. The
corallites are often only from half a line to a line apart in their
constricted portions, but they may be distant two, three, four,
or even five lines, and, on the other hand, they generally ap-
proach one another in parts of a large colony, so as to become
closely contiguous or coalescent.

Obs. — It is not necessary to add anything to the above de-
scription of the general characters of this singular species (PI.
VIII., figs. 2-2c). I may, however, shortly describe the ap-
pearances presented by thin sections, by which alone the internal
anatomy can be satisfactorily studied. The most instructive
sections are vertical ones (PI. VIII., fig. 2 c), which admirably
exhibit the alternately and rapidly constricted and dilated tubes
of the corallites, each of which looks like a series of wide and
shallow funnels arranged in vertical order. These sections also
show the important fact that the periodic expansions of the
tubes are really hollow prolongations of the visceral cavities of
the corallites, so that by the union of these to form the hori-
zontal connecting-floors all the polypes of the colony are placed
in actual organic connection. The tubes are traversed by well-
developed, arched, flexuous, or nearly horizontal tabulae, the
upper surfaces of which commonly carry short erect spines,

GENERA OF FAVOSITID^E. 157

and which more or less extensively anastomose with one an-
other, precisely as in the genus Michelinia, De Kon. The
tabulae are continued into the hollow horizontal expansions of
the tubes, where they continue to present the same characters
of irregular anastomosis as in the cavities of the corallites
themselves. Transverse sections (PI. VIII., fig. 2 b) exhibit
the corallites themselves, cut across at right angles to their
lonof axis, tos^ether with irreo-ular moieties of the hollow con-
necting-floors, which come into view in consequence of their
not lying in a single horizontal plane. The only special fea-
tures exhibited by sections of this nature are that the corallites
are provided with distinct and separate walls, and that the
septa are represented by radially-disposed spinules.

From the preceding description it will be clear that we have
to deal in Chonostegites Clappi, E. and H., with a coral in many
respects closely allied to Michelinia. If we take typical ex-
amples of this species, in which the corallites stand wide apart,
each enclosed in its own epitheca, and united with its fellows
by hollow horizontal expansions derived from the visceral cham-
ber, then, it Is true, we should feel no hesitation In separating
Chonostegites from Michelinia as a distinct genus. Even In such
examples, however, the hollow periodic expansions of the tubes
may be properly regarded as homologous with the "mural pores"
oi Michelinia. If, on the other hand, we examine a portion of
the colony of Chonostegites Clappi, In which the corallites are In
actual contact and have their walls perforated by numerous
mural pores, then we feel at a loss to produce a single charac-
ter by which the species could be generically separated from
Michelinia. Moreover, the curious AI. {Eimnonsia) cylindrica
of Edwards and Haime Is a distinct connecting-link between
the present species and the typical forms of Micheliniay since It
exhibits slight periodic constrictions of Its tubes, and the mural
pores are generally confined to the dilated portions of the
corallites.

Upon the whole, however, I prefer keeping Chonostegites dis-
tinct from Michelinia, In the meanwhile at any rate. It may be

158 TABULATE CORALS.

added that the reference of the genus by Mihie-Edwards and
Haime to the HalysitidcB, in the vicinity of Syringopora, is based
upon a soHd foundation of structural hkeness, since the connect-
ing-floors of Chojiostegites are the homologues of the hollow
connecting-tubes in Syringopora, and the genus thus forms a
true link between Micheliiiia and Syringopora.

Formation and Locality. — Not uncommon in the Corniferous
Limestone of Walpole, Ontario.

159

CHAPTER VI.

GENERA OF FAVOSITID/E {contmued).

Genus Columnopora, Nicholson, 1874.

(Geol. Mag., new sen, vol. i. p. 253, fig. i.)

Hoiightonia, Rominger, Foss. Cor. of Michigan, p. 17, 1876.

Gen. Char. — Corallum massive, forming subhemispherical or
pyriform masses, often of considerable size, composed of sub-
polygonal or subcircular corallites, which radiate from the base,
and are for the most part in contact and firmly united by their
walls. Septa in the form of marginal ridges, generally about
twenty in each corallite. Walls thick, perforated by numerous
large, close-set, oval mural pores, arranged in rows between the
septal ridges. Tabulae numerous, generally more or less flexu-
ous, often uniting with one another, complete. No columella
and no true coenenchyma.

Obs. — The corallum in this genus is massive, and in general
aspect very similar to that of any of the larger species of
Favosites, though distinguished from the latter even by a very
cursory examination. The corallites are in reality subpolygonal,
but the angles of the tubes are more or less rounded off,
and they thus become subcircular in form (PI. VII., fig. 2).
The real structure of the corallum can be best investigated by
means of transparent sections, though many of its most import-
ant features can be studied in the actual specimens. The coral-

i6o TABULATE CORALS.

lltes are essentially in contact with one another — if not invari-
ably, certainly as a general rule — throughout their entire length;
though occasionally limited tubular spaces are left at the point
of junction of three or four of the corallites.^ Moreover, thin
transverse sections (PI. VII., fig. 2 a) prove incontrovertibly
that the walls of the corallites are firmly amalgamated with one
another, the junction between contiguous tubes being marked
by a wavy dark line. Occasionally, as just remarked, the sec-
tions show a tubular space at the angles of junction of the
corallites, and these spaces are definitely circular or oval, and
are accompanied by smaller rounded and definite vacuities (PI.
VII., fig. 2 b), which are situated in the substance of the walls
themselves. These spaces I regard as being cross-sections of
tubes which pass through the thick walls longitudinally, and as
being, therefore, of the same nature as the canals which I have
described in PleiLrodidyum under the name of " intramural
canals." Similar tubes occur in the walls of Lyopora, Nich.
and Eth. jun. ; and though I am uncertain as to their true
nature, they are clearly endothecal, and cannot be of the nature
of " coenenchymal tubes." They are, further, very minute, and
only the largest of them would be recognised by the use of a
hand-lens upon actual specimens. Vertical sections (PI. VII.,
fig. 2 c) entirely confirm the evidence derivable from transverse
slices as to the absence of anything which could properly be
called coenenchymal. The walls, as before, are firmly united,
and the boundary between contiguous tubes is marked by a
sinuous dark line, occasionally interrupted by an irregular or
oval space. The septa are best studied in transverse sections
(PL VII., figs. 2 a and 2 b), though excellently seen in the actual

^ Occasional and partial absence of complete contact between the tubes is by no
means an unusual phenomenon in genera in which the corallites are normally and
regularly polygonal and accurately contiguous. Thus, in Coluinnaria {Favistelld)
alveolata, Goldf., it is not uncommon for the tubes close to their mouths to become,
in parts of the corallum, slightly separate, in which case they are also subcircular,
though the corallites are ordinarily prismatic and in close contact. In Coluinnaria
{Favistella) calicina, Nich., again, some of the corallites are always more or less
disjunct and subcircular, while others are always polygonal and firmly united by
their walls.

GENERA OF FAVOSITIB^. i6i

specimens themselves. They have the form of from fifteen to
twenty or more longitudinal ridges, which have broad bases,
and extend only a very limited distance inwards towards the
centre of the visceral chamber. The tabulae are seen in verti-
cal sections (PI. VII., fig. 2 c) to be complete and numerous,
more or less flexuous, and often uniting to a limited extent with
one another. They do not, however, carry this process of
anastomosis so far as to give rise to anything like the " sub-
vesicular " tabular tissue of Michelinia. Lastly, the mural pores
are seen both in transverse and longitudinal sections, though
best in the latter. In transverse sections (PI. VII., fig. 2 a)
they appear as transverse channels crossing the walls, and allow-
ing contiguous tube-cavities to communicate. In vertical sec-
tions they are only seen where the plane of the section may
happen to coincide with that of one of the walls of the tubes,
and then they are seen to have the form and arrangement ob-
servable by the ordinary methods of examination in the actual
specimens. They appear, namely (PI. VII., figs. 2 c and 2 d),
in the form of numerous longitudinally-placed oval pores of
large size, which occupy the interseptal spaces, and place the
visceral cavities in direct and free communication. The num-
ber of these pores in a given space is not absolutely uniform
in all parts of a given specimen ; but they are usually placed
at much less than their own diameter apart, measured both
vertically and laterally, so that the walls become completely
cribriform.

In his excellent work upon the Fossil Corals of Michigan, Dr
Rominger, in 1876, founded the new genus HoiLghtonia, to in-
clude certain corals from the Cincinnati group of North Amer-
ica, which I cannot doubt to be really congeneric with the
previously described Coliimnopora. Indeed, Dr Rominger has
himself admitted this identity in a note appended to a later
edition of the same work (1877). In his description of the
genus Hotightonia, as originally published, and in the note just
alluded to, in which he admits that this name must be abandoned
in favour of Cohmmopora, Dr Rominger states that the coral-

L

1 62 TABULATE CORALS.

lites are often separated from one another by an irregular
cellular coenenchyma, and that the walls of the tubes when
contiguous are not perforated by mural pores, though he gives
no drawings of the structure of the corallum which would sup-
port either of these statements. I cannot, of course, offer any
opinion as to the phenomena presented by Dr Rominger's speci-
mens, as I have not had any opportunity of examining them,
and I should not wish to dogmatise as to examples which have
not come under my direct observation. It must be borne in
mind, however, that the specimens in my possession are the
ones upon wJiich the genus was founded, and that they are there-
fore the types of the genus. These specimens have been sub-
jected to a careful macroscopic and microscopic examination,
and I can confidently affirm that they possess walls of an exag-
geratedly perforate type (as compared with Favositcs) ; that
their corallites are for the most part indubitably in contact, with
their walls absolutely fused with one another; and that any
interspaces which may here and there exist between the coral-
lites admit of being explained upon a different supposition than
that they are of the nature of " ccenenchymal tubes." The
drawings which I have given, being taken by the camera lucida
from microscopic slides, will sufficiently prove the accuracy of
these statements.

A more difficult point to settle concerns the relations of
Columnopora to Calaposcia, Billings ; and as I have no speci-
mens of the latter, I shall here say the little that is necessary
concerning the curious types included by the eminent Canadian
palaeontologist under the above name : —

The genus Calapcecia was defined by Mr Billings in the
'Canadian Naturalist' (2d sen, vol. ii. p. 425, 1857) as
follows : —

" Corallum composite, forming hemispherical or subspherical
colonies. Corallites slender, tubular, perforated as in Favosites,
and with their outside striated by imperfectly-developed costse.
Radiating septa (in the species at present known) about twenty-
four. Tabulae thin, and apparently in some instances not com-

GENERA OF FAVOSITJD.E. 163

plete. When the corallites are not in contact, the space be-
tween them is filled with a variously-formed vesicular tissue.
This genus resembles Heliolites, but differs therefrom in having
double the number of septa and the w^alls perforated."

Two species were described by Mr Billings as belonging to
this genus — viz., C. Canadensis, from the Black River Lime-
stone, and C. Hnroncjisis, from the Hudson River formation.
The former is stated to have corallites about one line in dia-
meter, and generally in contact, although still remaining cir-
cular ; while the mural pores are arranged in horizontal rows
running all round the tube, one row between each pair of tabulae.
The latter was separated specifically from C. Canadensis, prin-
cipally upon the ground of the greater slenderness of its tubes.
Neither of these forms was figured. From the above descrip-
tion it would appear that Calapoecia Canadensis and C. Huj^on-
ensis are corals nearly allied to the form which I have de-
scribed as Colwnnopora cribri/ormis ; but such a conclusion has
been rendered very hazardous by the publication by Mr Bil-
lings, at a later date, of a third species of Ca/apcecia, which was
both described and figured (Cat. Sil. Foss. of Anticosti, p. 32,
fig. 15, 1866), The species in question (viz., C. Anticostiensis)
is stated to have a hemispheric corallum, the corallites some-
times in contact, but usually distant from one another by a
quarter or half a line. The shape of the corallites is circular,
and they are surrounded on the exterior by a fringe of well-
developed costcB, while the spaces between them are subdivided
by horizontal and close-set exothecal plates. The septa have
the form of longitudinal striae, and tabulae were only obscurely
seen. In a note Mr Billings adds that this species would seem
to be congeneric with Syri^igophyllwn organ7im.

Whether or not Mr Billings be correct in the suggestion just
alluded to, the above description and the figures which accom-
pany it leave no doubt whatever as to the entire distinctness
of Calapoecia Anticostiensis, Bill., and ColiLvmopora cribri/ormis,
Nich. If, therefore, the originally-described species — viz., Cala-
poecia Canadensis and C. Htironensis — are to be regarded as

1 64 TABULATE CORALS.

congeneric with C. Anticostiensis, then it is clear that the genus
Columnopora has no relationships with Calapoecia. This, at
any rate, seems to be the only conclusion that can safely be
arrived at, until the original specimens of Calapoecia shall have
been more fully examined and described.

The geological range of Cohcmnopora, so far as known, is a
very limited one, the type-species being confined to the Lower
Silurian (Cincinnati group) of North America. The type of
the genus is C. cribriformis, Nich., of which I append the fol-
lowing brief description. Judging from the figures given, I
should imagine C. {Houghtonid) Htirojiica, Rom., to be at
most a variety of C. cridrifoi^uis ; but as the corallites are
apparently to a considerable extent disjunct, it may prove to
be a separate species when it shall have been examined by
means of thin sections.

Columnopora cribriformis, Nicholson.

(PI. VII., figs. 2-2 d.)

Columnopora cribriformis, Nicholson, Geol. Mag., new ser., vol. i. p. 253, fig. i,
1874; Pal. Ohio, vol. ii. p. 186, PI. II., figs. 8-8 ^, 1875; Second Rep.
Pal. Ont., p. 25, 1875.

Spec. Char. — Corallum forming hemispheric or pyriform
masses, which vary in diameter from ten lines to half a foot
or more, and in height from eight lines to three or more inches.
Corallites spreading from the base of attachment, essentially
polygonal, and for the most part in close contact, their walls
thick and fused together ; occasionally becoming subcircular,
and partially separated by narrow interspaces as their mouths
are approached. Calices rounded or distinctly polygonal, aver-
aging one line and a half in diameter, smaller ones being often
intercalated here and there among those of ordinary dimen-
sions, their margins thick and crenulated by the septa. Septa
about twenty in number, more or less, in the form of strong
longitudinal ridges, which pass but a short distance inwards to-

GENERA OF FAVOSITIDJE. 165

wards the axis of the visceral chamber. Mural pores large,
oval, arranged in longitudinal rows between the septa, and
separated by intervals as a rule much less than their own
diameter. Tabulae numerous, complete, flexuous, often uniting
with one another, generally about eight in the space of two
lines.

Obs. — The above description is based upon specimens from
the Cincinnati group of Ohio, as regards its essential features ;
though, as regards one or two characters, I have had in view
examples from the corresponding formation in Canada, which
I believe to belong to the same species. Thus, in the Canadian
examples, the tubes are more liable to show a circular form,
and to be at times partially separated near their mouths, than
is the case with those from Ohio. On the other hand, the
latter usually show polygonal and closely-contiguous tubes.
Having fully discussed the structure of this species in dealing
with the genus, I need only add that it would seem probable
that the Columnopora {Houghtonia) Huronica of Rominger
(Foss. Cor. of Michigan, p. 17, PI. III., figs. 3 and 4) is really
identical with Cobminopora cribri/ormis, Nich. As, however,
Dr Rominger's description differs in some important respects
from that of the type-species as here given, and as I have not
had the opportunity of examining the specimens upon which
his account is based, I shall in the meanwhile consider it as a
separate species.

Formation and Locality. — In the Cincinnati formation. South-
western Ohio. Rare in the corresponding formation (Hudson
River group) of the Credit River, Ontario.

Genus ARyEOPORA, Nich. and Eth. jun., 1879.

(Fig. 24.)

Gen. Char. — Corallum massive, Favositiform, of polygonal
corallites, which radiate outwards from an imaginary axis to
open upon the free surface of the colony. Under surface

1 66 TABULATE CORALS.

covered by an epitheca (?). The corallites are firmly united
by their walls, which are extensively perforated by apertures
which place the visceral chambers of contiguous tubes in direct
communication. Septa trabecular, often irregularly divided, or
anastomosing at their free ends. Tabulae rudimentary, repre-
sented only by occasional horizontal trabeculse. No columella,
nor ccenenchyma.

Obs. — This genus is founded upon a remarkable specimen
belonofinof to the " Daintree Collection " of corals, from the
Devonian or Carboniferous deposits of Queensland, descrip-
tions of which will shortly be published by Mr R. Etheridge,
jun,, and myself. Pending the publication of our joint memoir,
I shall simply avail myself here of the permission of niy col-
league to briefly discuss the characters and affinities of the
genus ArcEOpoi'a, as deduced from the only species with which
we are as yet acquainted, and which we propose to name
A. A 7CS trails.

The corallum in our specimen o( Ar^opora Austi'alis might
at first sight be taken for that of any of the larger and more
massive species of Favosites (such as F. kemisp/iericay Yand.
and Shum.) ; though even to the naked eye the absence of dis-
tinct tabulse and the cribriform or porous condition of the walls
are striking features. The height of the specimen (which is
an imperfect one, and is not only silicified, but is likewise thor-
oughly infiltrated with silica) is rather more than three inches,
and its greatest width something over four inches. Its form
is pyriform, the narrow base having evidently been attached
to some foreign body, while the under surface was almost cer-
tainly covered with an epitheca, of which no traces now remain.
The calices must have opened over the whole of the convex
upper surface, but none of them are preserved in the example
before us. The corallites radiate with a graduated divergence
from the imaginary axis of the colony, and their form is reg-
ularly prismatic or polygonal, as in Favosites. This character
is much more perceptible to the eye, or when the surface is
examined with a lens, than it is when thin sections are inves-

GENERA OF FA VOSITIDyE.

167

tigated under the microscope, as it is to some extent masked in
the latter case by the broken and cribriform character of the
walls. The average diameter of the corallites is about two-
thirds or three-fourths of a line. The tubes are completely in
contact, and the walls of contiguous corallites are undistinguish-
ably amalgamated (fig. 24, a and b). Thin sections, whether

Fig. 24. — A, Part of a transverse section of Artropora Australis, Nich. and Eth. jun., en-
larged eight times, showing the trabecular septa and porous walls ; B, Part of a vertical
section of the same similarly enlarged, showing the cribriform character of the walls, the
septa, and the rudimentary tabulae. Devonian (?), Queensland. (Daintree Collection).
In these figures the matrix, which is really transparent, is represented as if opaque.

transverse or vertical, show that the walls of the tubes are
extensively porous and cribriform (fig. 24, a and b), being
pierced by numerous apertures, which place the visceral cham-
bers in direct communication. Transverse sections, further,
serve admirably to show the character of the irregular trabec-
ular septa, some of which are short and spiniform, while others
divide at their ends, or even unite with their neighbours. Ver-
tical sections show that the septa are upon the whole placed in
longitudinal rows, and they exhibit in addition occasional hori-
zontal trabeculae (fig. 24, b), which may be regarded as of the
nature of rudimentary tabulae.

From a consideration of the above characters, it cannot be
doubted that we have to deal in Ai'ceopora with a genuine

1 68 TABULATE CORALS.

" Perforate " coral, which, however, Is closely allied to the
Favosi tides, and may be best placed in this family rather than
in any of the more regular groups of the Perforata. By the
characters of its walls and septa the genus presents certain
alliances with the Poritida, but its general form and aspect are
those of a Favosites, and the presence of rudimentary tabulae
would still further confirm the view here taken. Among the
genera of the Favositidce, Arcsopora finds its nearest ally in the
Lower Silurian genus Coliinniopora, Nich., which it nearly re-
sembles in form and habit. It is distinguished from the latter,
however, by the less regularly perforate character of its walls,
by the rudimentary condition of its tabulae, and by the irregu-
larly-dividing and trabecular septa. I am unable to institute
any comparison between Arceopora and the Cretaceous Kon-
t7ickiay E. and H., but the septa of the latter seem to be
merely spiniform (six in number), and the tabulae are said to
be well developed and complete.

The geological horizon of Ar^opora Attstralis, Nich. and
Eth. jun., is not quite certain, but it occurs in deposits of
Devonian or Carboniferous age (the former most probably)
in Queensland.

6^^;^?/^ S TEND FOR A, Lousdale, 1844.

(Appendix to Darwin's Volcanic Islands, p. 161, 1844, and in Strzelecki's
Phys. Hist, of New South Wales, p. 262, PI. VIII., 1845.)

Tnbidiclidia, Lonsdale, in Murchison's Geol. of Russia, p. 601 (note), 1845.
(Non Stenopora, M'Coy, Brit. Pal. Foss. p. 24, 185 1.)

Gen. Char. — Corallum ramose, or sublobate, rooted below, and
composed of tubular corallites, which are nearly vertical in the
centre of the branches, and radiate outwards from an imaginary
axis to open on all points of the free surface. Corallites in
the centre of the branches, polygonal, thin-walled, and more or
less completely in contact ; but in the outer curved portion
of their course, more or less cylindrical, and annulated by

GENERA OF FAVOSITID^. 169

periodical ring - shaped thickenings, which are placed at cor-
responding levels in contiguous tubes, in such a manner as
to leave vacant spaces between the intervening unthickened
portions. Visceral chamber in the outer portion of the tubes
alternately contracted and dilated in correspondence with the
periodical thickening of the walls of the corallites just spoken
of; but open and subpolygonal in the axial portion of the cor-
allum. Septa obsolete. Tabulae remote, usually placed at cor-
responding levels in contiguous tubes. Mural pores of small
size, not numerous, and irregularly distributed.

History. — The genus Stenopora, Lonsdale, was first described
by its author in a note in Darwin's ' Volcanic Islands,' but was
more fully defined in Strzelecki's * Physical History of New
South Wales ' as follows : " A ramose spherical or amorphous
tubular polypidom ; tubes polygonal or cylindrical, radiated
from, a centre or an imaginary axis, contracted at irregular
distances, but in planes parallel to the surface of the speci-
men ; tubular mouths closed at final (?) period of growth ;
ridges bounding the mouths granulated or tuberculated ; addi-
tional tubes interpolated."

It is quite clear, as properly pointed out by Dana (U.S.
Expl. Exped. Zoophytes, p. 537, 1848), that the above generic
diagnosis is insufficiently characterised ;^ and to this must be
ascribed the great confusion in which the genus has subse-
quently become involved. Professor Dana, in the work just
quoted, defines the genus as follows : —

" Internal structure of corallum fine prismatic; cells of sur-
face minute, subangular, contiguous ; zoophytes glomerate or
ramose ; surface often small-verrucose."

This definition, also, really adds nothing to our knowledge of
the actual structure of the genus ; and it is therefore no matter

1 In the original description of Stenopora in Darwin's 'Volcanic Islands,' Mr
Lonsdale does give a character of generic value — viz., the gradual closure of the
mouths of the tubes by the deposition of calcareous matter on the interior of the
wall, giving rise to what he regarded as periodical "constrictions" of the tubes;
though these are really periodical " thickenings " of the wall, it being only the
visceral chamber that is " constricted."

I70 TABULATE CORALS.

of surprise to find that Milne-Edwards and Haime at first
accept the genus in part (Brit. Foss. Cor. Intr., p. Ixi, 1850),
with the clearly insufficient definition that the corallum is
" very similar to Chcetetcsl' but has " small styliform pro-
cesses at the angles of the calices ; " and then immediately
afterwards (Pol. Foss. des Terr. Pal., p. 261, 185 1) merge
the genus with Chcstetes, Fischer.

Mr Lonsdale's definition of Stenopora was founded (as also
Professor Dana's) upon specimens derived from Australia and
Van Diemen's Land ; and, so far as known, all the examples
in the hands of these observers were of Devonian or Carboni-
ferous age. At this point, however, the history of the genus —
which need not here be followed out in detail — became compli-
cated by the reference to it by Professor M'Coy of a number
of Silurian Corals (Brit. Pal. Foss., p. 24, 1851). The defini-
tion of Stenopora given by M'Coy is as follows : —

" Polypidom polymorphous, composed of round or polygonal
tubes radiating from an imaginary axis to the surface, where
the bounding ridges are tuberculated ; young tubes interpolated
by lateral budding between the old ; tubes constricted at irreg-
ular distances in planes parallel with the surface, and partially
closed at the orifice by a concave diaphragm perforated in the
centre ; no connecting tubuli, nor foramina."

The only species unhesitatingly referred to the genus by
M'Coy is one which he identifies specifically with the Calaino-
pora fibrosa of Goldfuss (Petref Germ., PI. XXVI IL, figs. 3 a,
3 b, 1829). The examples upon which Goldfuss founded this
species were derived from North America; and as I have not
had the opportunity of examining the originals, I can only
say that the figures of the German palaeontologist would pass
very well as figures of such a species of Stenopora as S. ovata,
Lonsd. Calamopora fibrosa, Goldf., was, however, subsequently
referred by Milne-Edwards and Haime to Favosites, under the
name of F. fibrosa (Pol. Foss. des Terr. Pal., p. 244), and the
species was stated to occur in the Lower and Upper Silurian,
and also in the Devonian, in Britain, Europe, and North

GENERA OF FAVOSITID.E. 171

America. I have never myself been so fortunate as to meet
with any specimens which I could refer without doubt to
Favosites fibrosa, Goldf. sp., as defined by the eminent French
authors above referred to ; and I am therefore quite unable
to express any opinion as to its affinities. It seems, however,
quite certain that the corals described by Professor M'Coy
under the name of Steiiopora fibrosa, Goldf. sp., have in reality
no relations whatever with the true Stcnopora of Lonsdale. On
the contrary, it is almost certain that they belong to the genus
Chcetetes, Fischer, or to Montictilipora, D'Orb., as ordinarily
understood ; and the same may be pretty confidently asserted
of all the examples of Stenopora which have subsequently been
quoted by various writers as occurring in the Silurian deposits
of various parts of the world. At the same time, though I
think that we have at present no actual evidence of the exist-
ence of any species of Stenopora in the Silurian rocks, it is
quite possible that a more extended investigation may yet
show some of the so-called Montiadiporcs of the Silurian to be
really referable to the former genus. We shall subsequently
see, indeed, that there are certain of the Silurian Monticuli-
poriB which, except in the apparent absence of " mural pores,"
make a very close approach in structure to Stenopora.

It is quite clear, further, that with the available information
as to the structure of the genus Stenopora, Lonsd., it was im-
possible to establish any satisfactory generic distinction between
this type and Chcetetes or Alonticnlipora ; and this view was the
one finally adopted by Milne-Edwards and Haime, and subse-
quently followed by myself (Quart. Journ. Geol. Soc, vol. xxx.
p. 499, 1874). To this opinion I should have been still in-
clined to adhere; but Professor De Koninck has shown that
one of the species described by Lonsdale (viz., 6". ovatci) pos-
sesses perforated walls, and is therefore fundamentally separ-
ated from the entire family of the ChcstetidcB. Indeed he refers
the species just mentioned to the genus Favosites itself. I have,
moreover, recently had the opportunity of examining a tolerably
extensive series of examples of Stenopora, mostly collected by

172 TABULATE CORALS.

Mr R. L. Jack, F.G.S,, in Queensland ; and having made a
careful microscopical examination of the genus by means of
thin sections, I am able not only to confirm De Koninck's
reference of the genus to the Favositidcs, but to show further
that its characters are entirely peculiar, and such as to separate
it generically from all the other members of the family. The
specimens in question formed part of a collection of Australian
corals which will shortly be described by Mr Robert Etheridge,
jun., and myself; and it is to the kindness of my colleague that
I owe the permission to use here the previously given generic
diagnosis, as well as the following observations upon the struc-
ture of Stenopora. Pending the publication of our joint memoir,
however, I shall not add in this place any descriptions of the
species, merely remarking that the forms which we have ex-
amined appear to be referable to three species, one of which
is identical with S. ovata, Lonsd., while a second seems to be
new {S. Jackii, Nich. and Eth. jun.), and the third is not in a
condition to admit of definite specific identification.

Obs. — Taking 6^. ovata, Lonsd., as the basis of the following re-
marks, the corallum in Stenopora is usually more or less branched;
but the branches may be so thick, and may so extensively coal-
esce, that its general form becomes that of a lobate mass. The
corallites (fig. 25, a) radiate in all directions from an imagin-
ary axis, and present very different appearances in the central
and circumferential portions of the corallum respectively. In
the axial portion of the branches the tubes are nearly vertical,
have thin walls, are essentially polygonal or prismatic in shape,
and are nearly or quite in contact with one another throughout.
As they pass upwards, the tubes gradually diverge, coming at
last to be nearly horizontal, and continuing in this direction for
some distance, till they at last open upon the surface. There
is thus an outer zone of the corallum in which the corallites are
nearly transverse to the axis of the branches, and within this
zone they present all their peculiar features. In this region,
namely, the corallites (fig. 25, b) assume a generally cylindrical
appearance, owing to the fact that their walls are thickened at

GENERA OF FAVOSITIDyE.

173

very short intervals by annular accretions of growth, the por-
tions of the tube between these retaining their normal diameter.
As these thickened portions of the corallites are placed at cor-

m

'^1

Fig. 25. — A, Portion of a branch of Stenopora yackii, Nich. and Eth. jiin., split open, of the
natural size ; B, Portion of the same enlarged, showing the annulations of the tubes in their
outer portions ; c, A few of the tubes of the same still further enlarged, showing the
mural pores. Pernio- Carboniferous formation, Queensland.

responding levels in all the corallites, it follows that the tubes
are actually in contact with one another at these points only,
and that they are separated by ring-like spaces corresponding
to all the unthickened segments of the tubes.

Thin sections of the corallum bring to light the peculiarities
just mentioned, along with others, the true significance of which
cannot at present be ascertained. Thus, if we take a trans-
verse section of a branch, and examine its central portion,
where the nearly vertical tubes are cut across approximately at
right angles to their course, we find that the corallites (fig. 26, b)
differ in no essential respect from those of Favositcs as re-
gards their general structure. Each possesses its own wall,
which is not excessively or abnormally thickened, and the
boundary between contiguous tubes is clearly marked by a
dark line. The tubes In this portion of the corallum are, more-
over, regularly polygonal, and are, as a rule certainly, in close
contact. If, on the other hand, we take a section tangential to
the branch, and just below its surface, we have the corallites cut
transversely across in the horizontal and annulated portion of
their course, and the appearances presented are very different
to the above. The tubes still appear to be in close contact and
to be polygonal, each being bounded externally by a well-

174

TABULATE CORALS.

defined dark line ; but the appearances of the area within this
boundary-Hne vary according as the section cuts the tubes at
the level of their thickened portions, or at that of the unthick-

Fig. 26. — A, Two tubes of Steno/ora ovata, Lonsd., cut transversely across their thickened
portions, and showing the contraction of the visceral chamber by an annular deposit of
sclerenchyma, which is not in contact with the wall on one side ; B, Two tubes of the
same from the axis of a branch, cut transversely, showing their thin walls and polygonal
form ; c. Portion of a tube of the same cut longitudinally, showing the thickening of
the wall, the tabulce, and one of the mural pores. Enlarged twenty-five times. Permo-
Carboniferous, Queensland.

ened intervals between the latter. In the former case, the
visceral chamber (fig. 26, a, and PI IX., fig. i a) is seen to be
greatly contracted, and to be reduced to a comparatively small
rounded or subpolygonal central tube, which is in turn sur-
rounded by a thickened ring of sclerenchyma, which usually
shows distinct traces of its being composed of successively-
deposited concentric laminse. In the latter case there is still a
ring of sclerenchyma within the dark outer polygonal boundary,
but this ring is of small thickness comparatively, and the cen-
tral tube is wide and open — the general appearances being on
the whole like those presented by cross-sections of the tubes in
the axial portion of the corallum. In both the above cases,
however, whether the section cut the corallites across their
thickened or their unthickened portions, there are two pheno-
mena observable which I am at present quite unable to explain.
One of these consists in the fact that the ring of sclerenchyma
within the corallites is never in contact with the outer polygonal

GENERA OE EAVOSITID.E. 175

wall for more than one half or two-thirds of its circumference,
being separated from the latter throughout the remaining part
of the tube by a distinct and conspicuous interspace, which is
filled in the fossil with transparent calcite. Not only is this
partial interspace between the inner ring and the outer wall
(PI. IX., fig. I a, and fig. 26, a) apparently always present, but
it seems to be always situated upon the same side of all the
corallites in any particular section. The other point that is
difficult to understand is how the outer dark walls of the coral-
lites should appear in tangential sections to be always in close
contact, seeing that an examination of the exterior of the tubes
with a lens shows that they are only in contact along the thick-
ened planes in which rings are developed, and are separated by
distinct intervals in the spaces between these. Moreover, in
many parts of tangential sections the corallites exhibit few
features that would satisfactorily separate them from similar
sections of the tubes of certain Monticttliporcs, though they
usually have exceptionally thick walls, and also often exhibit a
thin dark ring a little within the true wall, and concentric with
the latter. There are also some other phenomena occasionally
observable which it is extremely difficult to explain ; and it
seems clear that the precise structure of this curious type must
remain to some extent unelucidated until a large series of speci-
mens can be microscopically investigated.

Longitudinal sections of the tubes (fig. 26, c, and PI. VIII.,
fig. i) show the periodical annular thickenings of the tubes
in a very instructive manner, and show that these are really
tJdckenings of the zuall, projecting both externally and internally,
and that it is therefore incorrect to resfard the tubes as beine
" periodically constricted " — this phrase applying only to the
visceral chamber. In fact, the longitudinal section of the wall
has a regularly moniliform appearance, due to its successively
traversing thickened and unthickened segments of the tube.
Sections of this kind also show that there exist remote and
complete tabula;, which are usually placed at approximately
corresponding levels in all the corallites of a single colony.

176 TABULATE CORALS.

Lastly, these sections occasionally show mural pores, though
these structures can be best made out by a microscopic exami-
nation of the exterior of the tubes, when they are found to be
present in the form of small, circular, irregularly-distributed
apertures. It may be added that long sections show the same
curiously puzzling feature as do tangential slices — namely, that
the corallites are apparently in contact throughout their length,
whereas macroscopic examination shows them to be clearly free
over the unthickened segments of the tube.^

So far as can be at present ascertained, the species properly
belonging to Stenopora, Lonsd., as now worked out, are all
confined to the Carboniferous or Permo-Carboniferous periods,
there being some uncertainty as to the precise horizon of some
of the deposits which have yielded specimens of this type. So
far as known, also, the species of the genus are confined to
Australia and Van Diemen's Land. It cannot be said that any
species of the genus has been certainly identified in the Silurian
rocks, and all the Silurian corals which have been at various
times referred here must in the meanwhile be placed under
Monticidipora or Chcetetcs pending their complete examination
by microscopic methods. The internal structure oi Stcnopora, as
I have here described it, is such as to fundamentally separate
the genus from either Chcstetes or Montiailipora ; but I am
unable to say how far a mere examination of the surface with
a lens would enable an observer to separate a specimen of the
first from one belonging properly to either of the latter genera.
None of my examples, in fact, show the surface-characters in
a satisfactory manner ; but so far as I can judge, the general

1 Since the foregoing has been written, examples of Stenopora Tasmanienst's,
Lonsd., S. crinlta, Lonsd., and of a third form apparently referable to S. iji/ormis,
Lonsd., have been carefully examined by Mr R. Etheridge, jun., and myself. The
phenomena which these present v/ill be elsewhere recorded by us, and it will be
sufficient here to say that all the above species are true Stenopora:, though the two
last are massive, and in many respects widely unlike S. ovata in general appear-
ance. All of them, however, possess the peculiar fibrous thickenings of the walls of
the tubes in parts, and must therefore be regarded as congeneric with S. ovata.
They show, nevertheless, many very singular features, the two last in particular not
only differing considerably from S. ovata., but also differing in important characters
from one another.

GENERA OF FAVOSITID^. 177

aspect of the calices is very similar to that of some Monti-
ctUiporcB, and I should therefore doubt if simple inspection of
the exterior would enable one to identify a specimen of Steno-
p07-a. Certainly the presence of spines or tubercles on the lips
of the calices — even if a constant character — cannot be sup-
posed to have anything beyond a mere specific significance.
I shall, however, have occasion to show hereafter that the
spines and calicine tubercles of certain Stenoporcc and Monti-
culiporcB are not mere surface-ornaments, but that they in
reality are produced by the metamorphosis of a peculiar and
special series of corallites.

Genus Rcemeria, Milne-Edwards and Haime, 185 1.
(Pol. Foss. des Terr. Pal., p. 253.)

The genus Rcenieria was founded by Milne-Edwards and
Haime for the reception of the single species R. iiifttndibuli-
fera, the Calamopora inftindibtilifera of Goldfuss (Petref. Germ.,
t. i. p. "]%, PI. XXVII., fig. I, 1826). I reproduce here the
description given by these authorities both of the genus and
species : —

Genus Rcemeria. — " Corallum forming a rounded mass, the
corallites united by their walls, the tabulae infundibuliform."

Species, Roemeria inftmdibulifera, Goldf. — " Corallum massive,
sublobate ; the corallites unequal, intimately united by their
walls at certain places, although free near their summits ; calices
in general polygonal, of a diameter of two or three millimetres.
There are traces of thin and equal-sized rudimentary septa. A
vertical section shows that there are tolerably regular and
numerous tabulae, in the form of funnels let one into the other.
We do not know if mural pores are actually present."

The brevity of the above diagnosis is sufficient to show that
Milne-Edwards and Haime possessed but a partial knowledge
of the structure of the above species and of the genus which
they founded upon it ; nor is any additional light to be derived

M

178 TABULATE CORALS.

from an examination of the figure given by Goldfuss, except that
this indicates a coral in many respects very unlike the normal
forms of Favosites. I am unable personally to give any fresh
information as to the structure or affinities of this coral ; but Mr
George J. Hinde, who has lately examined the original speci-
men in the Bonn Museum, permits me to say that in his opinion
the relationships of this peculiar type, so far as they can be
determined without actual sections, are rather with Syringopora
than with Favosites. The walls of the corallites are very thick,
and the tubes (as noted by Milne-Edwards and Haime) are
actually not in contact near their mouths, while there is no
positive evidence as to the existence of mural pores. The
tabulae also are simply invaginated, without being so bent down-
wards in the centre as to give rise to a median tube ; so
that, on the whole, the corallum may " be compared with that
of a Syringopora, in which the connecting-processes are absent
and the corallites are in close contact." On the other hand,
my friend Mr Hinde has had the great kindness to allow me
access to his specimens of a most remarkable Favositiform
coral, which he has collected in the Niagara Limestone of
Canada, and which in some respects agrees with the published
description oi Rosmeria, E. and H.; and I am further indebted
to him for the permission to make use here of the following
condensation of its characters, drawn from the MS. of a paper
which he is about to publish on the subject.

Gemis Syringolites, Hinde, 1879.
(Fig. 27.)

Gen. Char. — Corallum composite, forming flattened expan-
sions, with a basal epitheca, in general appearance resembling
Favosites Gothla^idica, Lam. Corallites in close contact through-
out, prismatic, thin-walled, with one or more vertical rows of
mural pores on each prismatic face. Tabulae annular, curved
so as to be concave upwards, and depressed centrally so as to
give rise to a vertical median tube, which may be continuous

GENERA OF FA VOSITIDyE.

179

or may be crossed by an occasional partition, and which runs
down the centre of the visceral chamber of each corallite, and
possesses non-perforate walls. Septa represented by crenula-
tions of the walls of the corallite, which are continued over the
upper surfaces of the tabulae in the form of a series of short
spines or tubercles, arranged in radiating rows, till they ulti-
mately disappear in the depths of the central tube (fig. 27).

This extraordinary genus is only known by a number of
silicified specimens, in a state of beautiful preservation, col-
lected by Mr George J. Hinde in the Niagara Limestone of
Manitoulin Island, Canada, and about to be fully described by
him under the name of Syringolites Huronensis} Under these

'J ATI •)

Fig. 27. — A, A fragment of a colony oi Syringolites Hitrtmcnsis, Hinde, of the natural size ; B,
A single calice of the same, enlarged eight times, showing the central tube, and radiating
lines of septal tubercles ; c, Part of a corallite of the same, split open, and enlarged six
times, showing the composition of the central tube out of invaginated tabulae ; D, Part of
a corallite of the same, viewed from the exterior and enlarged six times, showing the
mural pores. Niagara Limestone, Manitoulin Island, Ontario. Coll. George J. Hinde.

circumstances, it would not be proper for me to do more than
to say that, after a careful examination of the specimens col-
lected by this indefatigable observer, I am able to entirely
corroborate his views as to the structure of the genus, while I
may justifiably add a few general remarks bearing upon the
connection between this new type and those which have been
previously considered.

In the first place, then, it is clear that in Syringolites, Hinde,
we are presented with a coral closely allied to Favosites proper,
as shown by its general form, its prismatic corallites, intimately

1 Since the above was written, Mr Hinde has published his description of S.
Huronensis [see Geol. Mag., Dec. ii., vol. vi. p. 244, June 1879).

i8o TABULATE CORALS.

united by their walls, and its possession of rudimentary spini-
form septa, of tabulse, and oi 7nur at pores. In the second place,
we have here a coral which really fulfils Goldfuss's ideal of
Calamopora — " diaphragmatibus transversis, e siphone proli-
fero ; " if it were at all possible to revive this name with justice
or advantage. It is, however, quite certain that not one of the
forms included by Goldfuss under the name of Calamopora —
not even his Calamopora [Rcemeria) infundibulifera — really
possesses a central siphonal tube, formed by the junction of a
vertical series of funnel-shaped depressions of the tabulae in
the middle line. Mr Hinde's specimens, however, place it
beyond a doubt that, in his SyiHngolites Huronensis, we have
precisely such a form ; and we are thus presented with a true
member of the Favositidce, which, in one of the most striking
points of its organisation, offers a distinct approximation to
certain of the forms included under the genus Syringopora. It
need only be added here that the present form is generically
distinguished from all those ordinarily ranged under Syringo-
pora, not only by the close union of the polygonal corallites
and the total absence of connecting-processes, but also by the
possession of mural pores in all respects resembling those
found in the type-species of the genus Favosites.

Genus Laceripora, Eichwald, i860.
(Lethsea Rossica, p. 490.)

Gen. Char. — " Corallum thick, elongated, curved, ramose, of
almost cylindrical branches ; the calices angular, unequally-
sized, united with one another [by their walls], and provided
with two, three, or more rudimentary vertical lamellae. The
corallites radiate regularly from a cellular or porous central
axis, and are intersected by thick tabulae, which are placed at
the same level in different tubes, so as to form a succession of
superimposed layers. The margins of the calices are crenu-
lated or uneven ; they may or may not be provided with rudi-

GENERA OF FAVOSITID.E. i8i

mentary vertical lamellae. The corallltes differ from one an-
other in size and shape, and are so amalgamated by their walls
that no distinct lines of demarcation can be distinguished be-
tween them " [" elles se soudent ensemble et forment des murs
confluents, de sorte qu'on ne peut pas les distinguer les unes
des autres "].

Obs. — I am not acquainted with any example of this genus,
and can do nothing more than give the above translation of
M. Eichwald's description of it. For the clearer understanding
of its characters I have likewise reproduced Eichwald's figures
(PI. VII., figs. 3- 3 (^), which, if reliable, would seem to indi-
cate a distinct generic type. These figures present us with a
ramose corallum, with a general resemblance to the dendroid
forms of Pachypora or Favosites ; with very thick-walled coral-
lites, which are furnished with a small number of strong mar-
ginal septa (PI. VII., fig. 3 a). The drawing given on PI.
VII., fig, 3 d, is said by Eichwald to be the "coupe transver-
sale," and it doubtless is the transverse section ; but it repre-
sents the outermost portion of such a section, where the tubes,
as they diverge outwards, become nearly horizontal, so that
we really see the corallites cut longitudinally. In this section
we see that the tubes — in accordance with the description given
by Eichwald — are intersected by thick tabulae, placed at cor-
responding levels in contiguous tubes.

There is nothing in Eichwald's description or figures which
would lead to any safe conclusion as to the systematic position
of Laceripora ; and no allusion whatever is made to the exist-
ence of mural pores. I have therefore provisionally included
the genus in the Favositidcs, simply in deference to the opin-
ion of Dr Lindstrom, who is probably acquainted with actual
examples of the genus, and who states that it is " nothing more
than a highly-perforated Favosites''' (Ann. Nat. Hist, sen 4,
vol. xviii. p. 12, 1876).

The only known species of the genus is the Laceripora crib-
rosa of Eichwald, which is stated to occur in the "grauwacke"
(Upper Silurian), and also in the Carboniferous formation.

TABULATE CORALS.

Genus Nyctopora, Nicholson.

Gen. Char. — Corallum composite, massive, of polygonal
corallites, which radiate from the base of the spheroidal coral-
lum, to open on its upper surface, and are in complete contact
throughout their entire extent. Walls of the corallites thin,
and so completely amalgamated that no trace whatever of the
oriofinal lines of division between the tubes can be detected.
Mural pores numerous, small, in more than one series, occupy-
ing the sulci between the septa. Septa in the form of marg-
inal vertical ridges, which extend along the whole length of
the tubes, from ten to fifteen in number in each corallite,
not divisible into an alternating series of longer and shorter
lamellae. Tabulae numerous, complete, horizontal.

Obs. — I have been obliged to establish this genus for the
reception of a coral from the Trenton Limestone of Canada,
which I have previously regarded as probably identical with
Columnaria Goldfussi, Bill. In its general form and aspect
this coral, in fact, is entirely similar to Cobimnaria Halli, mihi
(C alveolata, Bill.) ; and it does not differ in any superficially
obvious character from the typical species of Columnaria (C
alveolata, Goldf, and C. calicina, Nich.), except in the marginal
and comparatively rudimentary condition of the septa. Thin
sections, however, place it beyond a doubt that the walls of the
present form are perforated by mural pores, and that the coral
in question must be placed in the Favositidce. Whether or not
the walls of Columnaria (?) Halli are likewise perforate is a point
which at present I cannot determine, though I am inclined to
think that in this form also mural pores are present. If this
conjecture should be ultimately established, then this well-
known form (the Colmnnaria alveolata of American palaeon-
tologists) will also have to be removed to the genus now
under consideration.

The corallum in the only certainly ascertained species of
Nyctopo^'a is in the form of spheroidal or pyriform masses,

GENERA OF FA VOSITIDJS. 183

composed of polygonal and closely -contiguous corallites, the
walls of which are not only in contact, but are undistinguish-
ably amalgamated with one another (PI. IX., figs. 3-3 c).
The corallites radiate from the base of attachment, the lower
surface being probably covered with an epitheca, and the
calices opening upon the convex upper surface (PI. IX.,
fig. 3). The calices are polygonal, with moderately thick
margins, which are crenulated by the rudimentary septa (PI.
IX., fig. 3 c). Transverse sections (PI. IX., fig. 3 a) show
that the walls of contiguous corallites are completely fused
with one another, no trace whatever of the original line of
demarcation between neisfhbourinof tubes beinsf recoofnisable
under the microscope. Sections of this kind also show the
short marginal septa, to the number of from eight to twelve
or more in each tube ; while occasionally a mural pore is
laid open, connecting the cavities of contiguous corallites
directly with one another. Vertical sections (PI. IX., fig.
3 b) show that there are numerous thin, horizontal, and
complete tabulae ; and in parts where the section more
or less nearly coincides with the plane of the walls of any
of the tubes, we observe numerous unmistakable mural
pores. These apertures differ in no respect from the mural
pores of Favosites^ except that they are perhaps proportion-
ately smaller, and do not seem to obey any regular law of
distribution.

So far as known, this genus is confined to the Trenton Lime-
stone in North America, and it afibrds a very interesting link
between the Favositid(^ and the ColiLmnariadcs. It differs
from Favosites in the lamellar condition of the septa, which,
though rudimentary, are never spiniform ; and in the more
minute size and apparently irregular distribution of the mural
pores. On the other hand, though agreeing with Columnaria,
Goldf., in its general structure and appearance, and especially
in the character of its septal apparatus, it is fundamentally
distinguished from the latter (as our present knowledge stands)
by the perforated condition of its walls.

1 84 TABULATE CORALS.

Nyctopora Billingsii, Nicholson.
(PI. IX., figs. 3 - 3 ^0
Columnaria Goldfiissi, Nicholson, Sec. Rep. Pal. Ont., p. 9, 1875.

Spec. Char. — Corallum forming small spheroidal or pyrlform
masses, varying from seven lines in diameter and four lines in
height, to rather more than an inch and a half in diameter and
an inch in height. Corallites prismatic or polygonal, subequal,
about three-quarters of a line or rather less in diameter, their
walls everywhere contiguous and closely amalgamated. Septa
in the form of from eig^ht to twelve or more stronof marg-inal
ridges, which run the entire length of the tubes, and project to
a very limited extent into the interior of the visceral chamber.
Mural pores numerous, minute, circular, apparently not arranged
in any definite order. Tabulae horizontal, complete, about six
in the space of two lines.

Obs. — As I have discussed the structure of this coral in
dealing with the genus Nyctopora, of which it is the only known
representative, I have little to add here. The specimens in
my possession are all from the Trenton Limestone of Canada,
and they were identified by me, from an external examination
only (Sec. Rep. Pal. Ont., p. 9), as young examples of Cohim-
7iaria Goldfnssi, Bill. They agree, indeed, with the descrip-
tion of this species (Geol. Surv. Can. Report of Progress for
1857, p. 166, 1858) in most respects, but the latter is said to
form " large amorphous or subglobose masses," with from four
to six tabulae in the space of one line, the septa " rudimentary,
but distinctly striating the interior walls ; " whereas the present
form is always quite small, its tabulae are wider apart, and its
septa, though rudimentary, have the form of strong vertical
ridges. As it is not known whether or not mural pores are
present in Columnaria Goldfussi, Bill., no stress can be laid
upon this character ; but their undoubted presence in Nyctopora
Billingsii, taken along with the differences above noted, and

GENERA OF FAVOSITID.E. 185

the fact that Coiuuumria Goldfussi is beHeved to belong to the
Hudson River formation, would seem to point to the at least
specific distinctness of the present coral. If a further examina-
tion of C. Goldfussi, Bill., should show it to be possessed of
mural pores, then it also must be removed to the genus Nydo-
pora. Lastly, there is a close general resemblance between
the present form and Cohtinnaria (?) Halli, mihi (the Colum-
nm'ia alveolata of American writers), and it is not at all impos-
sible that the latter may be shown to have perforate walls, and
thus to truly belong to the present genus.

Formation mid Locality. — Not uncommon In the Trenton
Limestone of Peterboro', Ontario.

Gemis BiLLiNGSiA, De Koninck, 1876.
(Rech. sur les Foss. Pal. de la Nouv. Galles du Sud., p. 75, PI. II., fig. 4.)

Gen. Char. — " Corallum composed of compressed corallites,
united by their walls, and communicating freely with one
another by means of lateral openings. Calices small, ovate,
and furnished with a few septal striae. Tabulae apparently
absent."

Obs. — This genus was founded by Professor De Koninck
{loc. cit.) for a single species of coral [B. alveolaris), from strata
of Devonian age, near Zass, on the Murrumbidgee River, in
Australia. Not having seen any examples of the form in
question, I can simply reproduce the above generic diagnosis
and one of the figures (PI. IX., fig. 4) given by De Koninck.
Assuming the correctness of the description given — as to which
the great experience of this distinguished observer leaves little
room to doubt — we have to deal in Billingsia with a perforate
coral, belonging to the Favositidce, but distinguished from the
other members of this family by the suppression of the tabulae.
The mural pores are apparently numerous and of large size,
but they do not seem to have any serial arrangement. Profes-
sor De Koninck expresses the opinion that the genus is in-

1 86 TABULATE CORALS.

termediate between Aulopora and Syringopora; but it seems
hardly possible, with our present knowledge, to arrive at any
certain conclusions as to its true systematic joosition.

Genus Nodulipora, Lindstrom, 1873.
(Ofversigt af Kongl. Vetensk. Akad. Forhandl., No. 4, p. 14, note, 1873.)

Gen. Char. — " Polyparium turbinatum, totum e nodulis
minimis contextum, ceterum et forma et septis Favositarum.
Epitheca tenuis, longitudinaliter rugosa. Superficies calycigera
lata, plana. Calyces insequales, saepe in radios crescentes,
obovati, angusti vel circulares, polygonii et curvi. Muri incom-
pleti, perforati. Noduli corpore rotundo, processibus tenuibus
inter se conjuncti. Partes inferiores vel primarise polyparii
materia calcarea consolidatse. Superficies calycigera processus
radiciformes emittit." *' Species unica N. acuminata^ m. in
Dalhem, Gotlandia, reperta."

Obs. — I am not aware that Dr Lindstrom has ever published
any further description or any figures of this remarkable form ;
and as I am altogether unacquainted wath actual specimens, I
can add nothing to the above generic diagnosis. Judging from
this alone, Nodulipora^ Lindst, must be regarded as an
aberrant member of the Favositidce, with no marked affinities
to any other member of this varied family.

i87

CHAPTER VII.

COLUMNARIAD^ (lYOPORA AND COLUMNARIa).

Genus Lyopora, Nich. and Eth. jun., 1878.
(Mon. Sil. Foss. of Girvan, Fasc. i. p. 25.)

Gen. Char. — Corallum composite, massive, forming irregu-
larly spherical or pyriform masses, composed of tubular, sub-
cylindrical, or subpolygonal corallites, which are more or less
completely fused with one another. Walls of the corallites
extraordinarily thick and dense, apparently destitute of mural
pores. Septa rudimentary, marginal, few in number, having
the form of irregular obtuse ridges on the interior of the wall.
Tabulae strong and complete. No columella nor coenenchyma.
Obs. — The corallum in this genus is chiefly remarkable for
the great density of the walls of the corallites, contiguous tubes
being separated by partitions which may equal half or more of
diameter of the former (PI. IX., figs. 2 and 2 a). Moreover,
the walls of neighbouring tubes are completely amalgamated
with one another, so that the original boundaries of the coral-
lites are either quite irrecognisable, or can only be made out
more or less obscurely. Rough fractures, also, invariably
expose the interior of the tubes. The corallites are subpoly-
gonal or subcircular in shape, and are essentially in contact
throughout their entire lens^th. The dense intertubular scler-

1 88 TABULATE CORALS.

enchyma, however, exhibits very commonly small irregularly-
distributed and irregularly-shaped vacuities, which vary much
in number in different specimens, or even in different parts of
the same specimen. Sometimes they are almost wholly
absent, sometimes they are so far abundant that one may
count five or six in the wall surrounding one corallite ; while
they may be circular, oval, crescentic, or quite irregular in out-
line. They are seen both in transverse and vertical sections
(PI. IX., figs. 2 and 2 a), and they can often be detected
on the surface in the form of pits in the thick margins of
the calices. It would appear to have been the above structures
which induced M'Coy to place Lyopora favosa in the genus
Heliolites {PalcEOpoi'a) ; but microscopic sections prove, beyond
the shadow of a doubt, that they are certainly not " ccenen-
chymal " in their nature. They are either placed at the angles
of junction of the original corallites (when these can be detected
at all), or they run in the substance of the wall itself. It is
clear, therefore, that they cannot be " coenenchymal tubules ; "
but it is at the same time difficult to say precisely what they
are. Probably they are (as suggested by Mr R. Etheridge,
jun., and myself, loc. ciL, p. 28) mere vacuities due to imperfect
deposition of sclerenchyma ; but the more regularly-shaped
ones are possibly of the nature of the " intramural canals" of
Columnopora, whatever these may be.

As regards the other features in the anatomy of Lyopora, I
have failed to find any evidence of the existence of " mural
pores," after a careful examination of a large number of speci-
mens and of microscopic sections. I am not, however, prepared
to assert that mural pores may not ultimately be proved to
be present. The septa are entirely rudimentary, and have the
form of broad, obtuse, and somewhat irregular marginal ridges,
which project to an extremely limited extent into the visceral
chamber (PI. IX., fig. 2). The tabulae are strong and complete,
and, in the only species known, are usually remote and hori-
zontal (PI. IX., fig. 2 a).

COLUMNARTAD^. 189

The apparent absence of mural pores renders it impossible to
refer Lyopoj^a to the FavositidcB ; and the undoubted absence
of " coenenchymal tubules " entirely precludes any comparison
between it and the Helioporidcs. Under these circumstances
it is very difficult to state anything definite as to the systematic
place which the genus ought to occupy. Its general characters
are in many respects such as to approximate it to Cohwmaria,
Goldfuss, which will be discussed immediately ; but this can
hardly be said to make matters any clearer, for the precise
zoological relationships of the latter are still very uncertain.
Moreover, a close comparison of specimens and thin sections of
these two genera has convinced me that the points of resem-
blance between them are largely counterbalanced by points of
structural dissimilarity. Thus the typical forms of Cohcmnaria
not only want the extraordinarily thickened walls of Lyopoi^a,
but possess a septal system, which, even in its most rudimentary
condition, is a marked advance upon that of the latter ; while
the amalgamation of the walls of the corallites is never carried
to the extent of in any way obliterating or obscuring the line of
demarcation between contiguous tubes. The typical species of
Columnaria, indeed, present many features which would induce
us to place them among the Rugose Corals, whereas Lyopora
exhibits no characters save such as were supposed to be dis-
tinctive of the old group of the " Tabulata." Upon the whole,
therefore, I must at present leave the position and zoological
relationships of Lyopora entirely open questions.

So far as known, the geological range of the genus Lyo-
poi'a is an extremely limited one, the only recorded species
being the L. favosa, M'Coy, sp., of the Lower Silurian rocks of
Ayrshire. I subjoin a brief diagnosis of this singular species,
extracted from the * Monograph on the Silurian Fossils of
Girvan,' by Mr R. Etheridge, jun., and myself.

I90 TABULATE CORALS,

Lyopora favosa, M'Coy, sp.
(PI. VIII., figs. 3, 3 a, and PI. IX., figs. 2, 2 a.)

Palceopora (?) favosa, M'Coy, Ann. and Mag. Nat. Hist., ser. 2, vol. vi. p.

285, 1850.
„ faiwsa, M'Coy, Brit. Pal. Foss., p. 15, PI. I. c, fig. b, 185 i.
Heliolites {Palceopora) favosiis, Salter, Quart. Journ. Geol. Soc, vol. vii. p.

170, 1851.
Lyopora favosa, Nicholson and R. Etheridge, jun., Mon. Sil. Foss. Girvan, p.

26, PI. II., figs, i-i e, 1878.

Spec. Char. — Corallum composite, massive, spheroidal, hemi-
spherical, pyriform, or irregular in shape ; the corallites sub-
cylindrical, elliptical, hexagonal, or irregular in outline, firmly
united with one another. Calices usually circular or hexagonal,
averaging a line and a half in diameter, the lip coarsely granu-
lar. Walls imperforate, extraordinarily thick, the interspaces
between any two contiguous tubes being occupied by dense
calcareous tissue, of from three-quarters of a line to more
than a line in thickness, sometimes with minute and irregu-
lar vacuities. Septa rudimentary, often wanting in individual
calices, varying in number from two or three up to ten or
twelve or more, always abortive, and represented only by rough
and blunt ridges on the interior of the wall. Visceral chamber
crossed by strong, solid, complete tabulae, distant from a line to
a line and a quarter from one another.

Ql)s^ — Having discussed the characters of the genus Lyopora,
of which this is the only recorded species, at some length, it is
unnecessary to dilate upon the above specific diagnosis. The
reference of this curious form by Milne-Edwards and Jules
Haime to Heliolites inter stinctus, Wahl. (Brit. Foss. Corals, p.
250), has been shown by Mr R. Etheridge, jun., and myself
{loc. cit. supra), to have been caused by the erroneous figures
given by M'Coy of its internal structure. The form of the
corallum is very variable, but it was rooted at its base to some
foreign body, and the diverging corallites seem to have opened
over the whole of the free surface, no traces of an epitheca

COLUMNARIADyE. • 191

having come under my observation. The size of ordinary
specimens varies from an inch or less in height and breadth up
to half a foot or more.

Formation and Locality, — Abundant in the Lower Silurian
Limestone of Craighead, Girvan, Ayrshire.

Genus Columnaria, Goldfuss, 1826.

(Petref. Germ., t. i. p. 72.)

Columnaria (pars), Goldfuss, Petref. Germ., t. i. p. 72, 1826.
Favistella} Hall, Pal. N.Y., vol. i. p. 275, 1847.
Favistella, Nicholson, Sec. Rep. Pal. Ont., p. 21, 1875.

Gen. Char. — Corallum composite, massive, composed of poly-
gonal, closely-compacted and contiguous corallites, which are
united by their walls, but do not possess mural pores. Walls
of the corallites not excessively thickened. Septa well devel-
oped, typically extending nearly to the centre of the visceral
chamber, and alternately large and small. Tabulae extremely
well developed, complete, and horizontal. No columella or
coenenchyma.

Obs. — This genus was founded by Goldfuss to include certain
massive aggregate corals, which closely resemble Favosites in
general appearance, but differ in having lamellar septa and im-
perforate walls. Of the three forms included by Goldfuss under
this name, two appear to be compound Rugose corals, as shown
by Milne-Edwards and Haime (Pol. Foss. des Terr. Pal, p.
308, 1 851); and the title Columnaria can therefore only be
retained for the third of these — viz., C. alveolata, which occupies
the first place in the original description, and must therefore
be strictly regarded as the type-species. Nor can any doubt be

^ The name of Favistella was proposed in 1846 (U.S. Expl. Exped. Zooph., p.
538) by Dana for "a part of the true Favosites, in which the cells are stellate with
twelve distinct rays." There is, however, no sufficient evidence that Dana had in
view the true Columnarice, rather than the similar-looking forms of Favosites with
well-developed septa ; and it is quite clear that Hall introduced the name Favistella
quite independently.

192 TABULATE CORALS.

entertained as to the identity of the coral which Goldfuss de-
scribed and figured under the name of C. alveolata, with that of
the coral subsequently described and figured by Hall under the
designation of Favistella stellata (Pal. N.Y., vol. i. p. 275, PI.
LXXV., fig. i). Indeed, the original specimens described by
Goldfuss were derived from North America.

It is certain, then, that the genus Columnaria, if kept at all,
can only be retained for corals having the characters of C. alveo-
lata, Goldf { = Favistella stellata, Hall) ; and there is also no
doubt that the strict law of priority demands that this course
should be followed, and that the ill-characterised genus of Gold-
fuss should take precedence over the properly-defined Favistella
of Hall. I have elsewhere pointed out (Sec. Rep. Pal. Ont, p.
21) that this course is attended with grave inconvenience, in
consequence of the fact that the name of Columnaria alveolata
has been used generally, as by Hall, Billings, and others, for
an entirely different species to that so designated by Goldfuss.
In deference, however, to the opinion of authorities whom
I respect, I shall consider Favistella, Hall, as a synonym of
Columnaria, and I shall subsequently discuss the characters of
the coral which has been generally, but erroneously, described
as Columnaria alveolata, Goldf.

Taking, then, the true C. alveolata of Goldfuss (the Favistella
stellata of American palaeontologists) as the type of the genus
Columjtaria, we find that the genus includes massive corals,
of a hemispheric, pyrlform, or irregularly spheroidal shape, and
often of large size, composed of prismatic or polygonal coral-
lites, which radiate outwards from the base of attachment. The
walls of the corallites are not excessively thickened, and con-
tiguous tubes are usually in contact throughout their entire
length. An occasional and partial separation of the corallites
close to their mouths can, however, be sometimes observed ;
and in an allied species (C calicina, Nich.) the tubes become
to a large extent disjunct, though never wholly so, in the upper
portion of the corallum. The boundary-lines between contigu-
ous corallites are never completely obliterated (PI. X., figs, i

COL UMNARIAD^. 1 93

and 2), and weathered or roughly-fractured surfaces sometimes
exhibit the exterior of the tubes. No evidence has been ob-
tained by thin sections, or otherwise, as to the existence of
"mural pores," and it must therefore be presumed that the
walls are imperforate.

The septa (PI. X., figs, i and 2) are well developed and
lamellar, extending from the top to the bottom of the visceral
chamber, and reaching more or less nearly to the centre of the
tube, which they do not quite reach. There is sometimes a
curious irregularity of the septa, one or more being predomi-
nantly developed, and there are also two distinct sets of these
structures, a long and a short series, alternating regularly with
one another. Lastly, the tabulae are very numerous and well
developed, being complete and more or less horizontal, and not
placed at corresponding levels in contiguous tubes.

The affinities of the genus Cohmmaria are still very obscure.
If a more extended examination of specimens by means of thin
sections, with special reference to this point, should show the
walls to be really imperforate, as we must at present conclude
them to be, and as they probably really are, then we cannot
place the genus in the Favositidce. Nor is there any other
group among the old " Tabulate Corals " of Milne-Edwards
and Haime to which they could be referred with any greater
propriety. The genus, indeed, is much more like one of the
Rugosa than one of the " Tabulatay It possesses well-
developed and lamellar septa (in its type-forms at any rate),
and its tabulae are hardly better developed than in several
undoubted Rugose corals (such as Amplexiis, Diphyphyllum,
&c.) In fact, it might be at once, and without any violence,
placed in the Stauridce, close to Stauria, except that there is no
predominant development of four of the septa. On the other
hand, the genus has many points of likeness with Lyopora,
which has no Rugose affinities to speak of. Upon the whole,
therefore, it seems impossible at present to assign any definite
systematic place to Cohunnaria, and we must regard it as the

N

194 TABULATE CORALS.

type of a special family, to which the name of Cohtmnariadce
may be applied.

Professor Verrill (Amer, Journ. Sci. and Arts, ser. 3, vol. iii.
p. 191, 1872) has drawn attention to the resemblance between
Coltiinnaria and certain of the Astraeans (such as Ccelastrcsa),
and he has expressed the opinion that the genus, " if not actu-
ally a member of the Astrceidcs, should at least be referred to
a family very near that group." There is much to be said for
this view, but considering the less regular development of the
septal apparatus in Cohcmnaria, and its apparent want of any
endothecal dissepiments (apart from the " tabulae," if these
structures are regarded as dissepimental), I think it safer in
the meanwhile to leave the position of the genus an open
question.

The typical species of the genus Cohcmnm^ia are C. alveolata.
Gold, {lion M'Coy and Hall), C. Gothlandica, E. and H., and
C. calicina, Nich., all of which are Silurian in their distribution.
The first and last of these are principally Lower Silurian, and
the Upper Silurian C. Gothlandica, E. and H. (Pol. Foss. des
Terr. Pal., p. 309, PI. XIV., figs. 2 and 2 a), would appear to
be hardly separable specifically from C. alveolata, Goldf.

There remains the Silurian coral which has been described
by Hall, M'Coy, and other observers under the name of Colum-
naria alveolata, Goldf, with which we may possibly associate
certain other forms {e.g., C. erratica, Billings). This form I
shall briefly consider under the name of Cohimnaria (?) Haiti,
mihi, though I very greatly doubt if it be really referable to the
genus Columnaria of Goldfuss. As to the other forms which
have been included by various writers under the genus Colum-
naria, I can say nothing, as I have not had the opportunity of
examining actual specimens.

COL UMNARIA D^E. 1 95

Columnaria alveolata, Goldfuss.
(PL X, figs. I, I a.)

Columnaria alveolata, Goldfuss, Petref. Germ., t. i. p. 72, PI. XXIV., fig. 7,

1826.
„ multiradiata, Castelnau, Sil. Syst. de TAmer. sept., p. 44, PI.

XIX., fig. I, 1843.
Favistella stellata. Hall, Pal. N.Y., vol. i. p. 275, PI. LXXV., fig. i, 1847.

(Non Columnaria alveolata. Hall, ibid., p. 47.)
Columnaria alveolata (pars), Milne-Edwards and Haime, Pol. Foss. des Terr.

Pal., p. 309, 185 1.
„ Gothlandica, Milne-Edwards and Haime, ibid., p, 309, PI. XIV.,

figs. 2, 2 a, 185 1.
Favistella stellata, Nicholson, Sec. Rep. Pal. Ont., p. 23, 1875, and Pal. Ohio,

vol. ii. p. 185, 1875.
Columnaria stellata, Rominger, Foss. Cor. of Michigan, p. 90, PI. XXXIV.,

fig. 3, and PI. XXVIII., fig. i, 1876. (Non Columnaria

alveolata, M'Coy, Hall, Billings, Rominger, &c.)

Spec. Char. — Corallum massive, subhemispheric, or pyriform,
often attaining a very considerable size. Corallites prismatic,
hexagonal or pentagonal, but often more or less drawn out
along one axis, the larger ones being from rather less than two
to over three lines in their long diameter, and having numerous
much smaller tubes interspersed amongst them. Walls of the
corallites more or less amalgamated, the line of division between
contiguous tubes still remaining quite distinct. Mural pores
apparently wanting. Septa unequally developed, alternately
large and small, the latter quite rudimentary, and the former
extending usually across two-thirds of the distance between the
wall and the axis of the visceral chamber, or even reaching the
last-mentioned point. The septa are thin and flexuous but
completely lamellar, and the number of each series varies from
about twelve to fifteen or more. Tabulae complete, horizontal, or
somewhat flexuous, about six In the space of two lines. Callces
polygonal, unequally- sized, moderately deep, with thin margins,
usually closely contiguous, but sometimes separated by slight
interspaces ; the floor formed by the uppermost tabula, the
surface of which Is striated by the radiating septa.

196 TABULATE CORALS.

Obs. — Having given an account of this species in describing
the structure of the genus Cohminai^ia, I have httle to add to
the above specific diagnosis. I entertain no doubt at all that
the specimens described and figured by Goldfuss (Petref. Germ.,
PI. XXIV., fig. 7) are really the present form — so well known
to American palaeontologists under the name of Favistella stel-
lata, Hall — and that they are quite different to the species
described by Hall, M'Coy, and others under the name of C.
alveolata. Not only do Goldfuss's figures show the extension
of the septa to near the axis of the visceral chamber in the
clearest possible manner, but his examples were actually col-
lected on the shores of Seneca Lake, in the State of New
York, where the Lower Silurian Rocks do not occur in place,
so that they were doubtless derived from a travelled boulder
originally belonging to the Hudson River formation.

I should be inclined to think that a re-examination of the
specimens upon which Mr Billings founded his Columnaria
rigida (Geol. Surv. of Canada, Rep. of Prog, for 1857, p. 167,
1858) would show that these are really the same as C. alveolata.
Mr Billings himself states that the principal distinction between
the two is, that in C. rigida the septa do not quite reach the
centre of the visceral chamber, whereas in C. alveolata (which
he calls Favistella stellata. Hall) the septa not only reach the
centre, but are often " so strongly developed there as to pro-
duce by their junction the appearance of a pseudo-columella."
This last-mentioned appearance is one that I have never seen,
while it is quite common for the septa of C. alveolata to fall
short of the centre of the visceral chamber, as indeed the
most of them almost always do ; so that I hardly think C.
rigida, Bill,, can be retained as a distinct species.

Fo7nnation and Locality. — Abundant in the Cincinnati group
(Hudson River Group) of Canada and the United States. Dr
Rominger (Foss. Cor. of Michigan, p. 90) quotes it also from
the Niagara Group (Upper Silurian).

COL UMNARIADyE. 1 97

Columnaria calicina, Nicholson.

(PI. X., figs. 2, 2 a.)

Favistclla calicina, Nicholson, Rep. Brit. Ass., 1874, and Second Rep. Pal.

Ont, p. 24, fig. 9, 1875.
Cohunnaria Hertzeri, Rominger, Foss. Cor. of Michigan, p. 90, 1876.

Spec. Char. — Corallum subhemlspheric or pyrlform, of
moderate but not very large dimensions. Corallites partially
in contact and partially more or less completely separate from
one another, averaging about two lines in diameter, but vary-
ing from less than a line up to three lines. Where the coral-
lites are more or less uniformly contiguous (as always towards
the base of the colony), they are prismatic or polygonal. In
diverging from the base, however, the tubes separate from one
another to a greater or less extent, so as to leave more or less
conspicuous intervals between them. In these portions of their
course each corallite is surrounded by a distinct and separate
wall, which is marked exteriorly by strong vertical ridges and
intervening grooves, about five of which occupy the space of
one line, together with fine encircling striae. Septa alternately
large and small, twenty-eight in number altogether, the prim-
ary ones being continued over the upper surfaces of the tabulae
to near the centre of the corallites, whilst the secondary ones
are marginal and rudimentary. Tabulae well developed and
complete, about three in the space of one line. Increase by
calicular gemmation, combined with parietal budding.

Obs. — This pretty little species is very distinct from C. alveo-
iala, Goldf., from which it may be readily separated by the
followinof characters : i. It is much more diminutive in aver-
age size than C. alveolata, its colonies rarely exceeding three
inches in diameter and two inches in height, and being often
much smaller than this. 2. The corallites are comparatively
lax and discrete in their mode of growth. Rarely they may
be more or less contiguous and prismatic in form throughout
the greater part of their course. More usually, they are cylin-

198

TABULATE CORALS.

drical or subcylindrical, and as they radiate from the base,
become more or less widely separated towards their termina-
tions. Hence the surface of a mass of C. calicina (fig. 28)

Fig. 28. — I a, A colony of Coliivinaria calicina, Nicli., from the Hudson River Group of
Canada, of the natural size ; \ l\ h. single calice of the same enlarged ; 2, A calice of
Coliimnaria (?) Halli, Nich., {C. alveolata, auctt. non Goldf.), enlarged.

often presents an appearance similar to the convolutions of
the human cerebrum or to a colony of Fasciadaria. 3. It is
only where the corallites are in actual contact that their walls
are united, and in the rernaining portions of their course each
is enclosed in a distinct and separate wall, marked with con-
spicuous vertical ridges and fine encircling striae. 4. The
increase of the corallum is effected by calicular gemmation,
and apparently also to some extent by lateral budding, the
former mode of growth not seeming to occur in C. alveolata.
When we come to consider the internal structure of C.
calicina, we find that the differences which separate it from
C alveolata, Goldf,, depend principally upon the peculiar
mode of growth of the former, the anatomical characters of
the two species being very much the same. Transverse
sections (PI. X., fig. 2 ci) show that though the tubes in the
contiguous portions of their course are practically amalgamated
by their walls, the real duplicity of their walls is never lost, the
actual line of division between neighbouring corallites being
still conspicuously recognisable under the microscope. In this
respect, therefore, C. calicina entirely agrees with C. alveolata.
These sections, further, show a highly " Rugose " condition of

COLUMNARIAD^. 199

the septa, these structures being divisible into a double series
of alternately long and short septa, of which the latter are quite
rudimentary and marginal, while the former vary greatly in their
development. Sometimes they fall short of the centre by a con-
siderable interval — as is also usually the case In C. alveolata
— but In other tubes they nearly or quite reach the axis of
the visceral chamber. Moreover, the phenomena which the
septa exhibit are precisely such as every student of the Rugose
corals Is familiar with. The longer septa, namely, are not of
uniform length, but exhibit clear differences In their develop-
ment, almost amounting to that produced by the existence of
regular " cycles." Some of them quite reach the centre, others
fall a little short of it ; and there is even a tendency to the pro-
duction of a single predominant septum, or of two such, towards
the sides of which the remaining septa bend. Lastly, It is quite
common for the longer septa to be more or less united with one
another by their Inner ends In a series of fascicles, though at
other times each may be quite free.

Vertical sections of the corallum show no features of special
structural importance (PI. X., fig. 2 a). When they pass accu-
rately through the centre of the visceral chamber, the princi-
pal or only structures observable are the tabulae, which are com-
plete, essentially horizontal, though flexuous, and about six in
number In the space of two lines. On the other hand, when
the section passes at all out of the central line of the tubes, the
tabulae are cancellated by vertical lines representing the cut
edges of the septa. No mural pores have been detected.

Formation and Locality. — Abundant in the Cincinnati Group
(Hudson River formation) of the Credit River, Ontario. Dr
Romlnger quotes the same species (under the name of C.
Hertzeri, Rom.) from the Cincinnati Formation of Kentucky.

200 TABULATE CORALS.

Columnaria (?) Halli, Nicholson.
(PI. X, figs. 3, 3 a.)

Coli/mnaria alveolata, Hall, Pal. N.Y., vol. i. p. 47, PI. XII., figs, 1 a - c.

„ alveolaia, Billings, Geol. Can., fig. 70, p. 139, 1863.

„ alveolata, Nicholson, Sec. Rep. Pal. Ont., p. 8, 1875.

„ alveolata, Rominger, Foss. Cor. of Michigan, p. 89, PI. XXXIV.,

figs. I, 2, and 4, 1876.
(Non Columnaria alveolata, Goldfuss.)

Spec. Char. — Corallum forming large massive colonies, which
vary from a few inches to several feet in diameter, and which
are composed of variously- sized polygonal corallites, in close
contact with one another throughout their entire length. The
walls of the corallites are not excessively thickened, and they
are so completely amalgamated in contiguous tubes that even
under the microscope the original line of demarcation between
the tubes can be made out with difficulty or not at all. The
large tubes are usually from two to three lines in diameter,
though occasionally considerably more than this ; and the
smaller corallites are of all sizes. Septa marginal, in the
form of obtuse longitudinal ridges, which vary in number
from twenty to forty, do not extend to any distance into
the visceral chamber, and are not divisible into an alternat-
ino- loneer and shorter series. Tabulae stron^ horizontal,
and complete, about half a line apart or sometimes closer.
Mural pores not recognised with certainty.

Obs. — I have come to the conclusion, after full consideration,
that the best course to adopt with regard to this species is to
give it a distinct specific name, though it has so long been
known to palaeontologists as C. alveolata, Goldf, that this
course is attended with much inconvenience, and I have
myself elsewhere opposed it (Sec. Rep. Pal. Ont., p. 8).
Dr Rominger has evaded the difficulty, as I tried to do,
by reserving the name of C. alveolata for the form now
under consideration, and by retaining Hall's Favistella stel-
lata. It is, however, quite certain that the latter is really

COL UMNARIAD^.

the Cobtmnaria alvcolata of Goldfuss, and it is therefore best
to give the present species a distinct title rather than to per-
petuate a source of endless confusion. I am the more inclined
to take this course, as I am disposed to doubt very stronQ-ly if
the present form can be referred to Coluninaria at all, and
whether it is not truly a perforate coral, congeneric with
Nydopora^ Nich. The material in my hands is, however,
not sufficient to settle this point finally. All that I can
affirm is that Cobtmnaria (?) Halli agrees with Nyctopora
Billingsii, Nich., precisely in its general form and aspect, in
the complete amalgamation of the walls of the corallites, and
in the fact that the septa have the form of blunt marginal
ridges, not divisible into a double series. In all these points
C. (?) Halli differs from the true C. alveolata, Goldf , and from
the allied C. calicina^ Nich. I am disposed also to think that
I can detect in thin vertical sections of C. (?) Halli small
mural pores, such as are so abundant in Nydopoi^a Billingsii.
On the existence, however, of this crucial character, I must at
present speak with much reserve, for the state of preservation
of my specimens is such that I have not succeeded in obtaining
from them any microscopic sections that could be confidently
relied upon as deciding a point of such delicacy and importance.
Leaving the existence of mural pores an open question, I
have little to add to the

above specific diagnosis
of C. (?) Halli. The gen-
eral form of the corallum
(fig. 29) is very similar to
that of C. alveolata, Goldf.,
though the colonies most-
ly tend to assume a flat-
tened and laterally ex-
panded form. The coral-
lites are always polygonal
and prismatic, of very un-
equal sizes, but invariably in close contact throughout, and with

Fig. 29. — A small colony of Cohimnaria (?) Halli,
Nich., from the Trenton Limestone of Canada,
of the natural size. (After Billings.)

202 TABULATE CORALS.

walls of no more than average thickness. Transverse sections
(PI. X., fig. 3) show that the walls are so entirely amalgamated
in contio^uous corallites that it is difficult to detect the origfinal
boundaries of the tubes. The same sections show that the
septa are in the form of strong vertical ridges, which vary
in number in tubes of different dimensions, but are invariably
marginal, and never extend beyond a very limited distance into
the interior of the visceral chamber. There is also no trace of
that division of the septa into an alternately-disposed long and
short series, such as has been seen to be so characteristic of
C. alveolata, Goldf , and C. calicina, Nich.

Vertical sections (PI. X., fig. 3 a) exhibit principally the
strong, remote, and complete tabulae ; but when the plane of
the section comes to coincide more or less closely with the
plane of one of the walls of the tube, we observe also a
series of vertical ridges or bands, which represent the broad
edges of the septa as seen in section. In such parts of vertical
sections, I think I can detect, as before said, small mural pores,
but I cannot affirm this positively.

For7natiou and Locality. — Abundant in the Trenton Lime-
stone of Canada and the United States. Professor Hall's
specimens seem to be exclusively from the Black River
Limestone, which forms an inferior division of the Trenton
Limestone in the State of New York. It has not hitherto
been detected in the Cincinnati formation (Hudson River
Group) ; and this of itself is to some extent evidence of its
distinctness, considering that Columnaria alveolata, Goldf.
{Favistella stcllata, Hall), is such a common coral in the
latter formation.

203

CHAPTER VIII.

SYRINGOPORID^.

In the family of the Syringoporidce^ as typified by Syringopora
itself, there is a fasciculate corallum, commencing in the form of
a reticulated tubular expansion, which sends up at intervals
vertical, more or less cylindrical corallites, enclosed in strong
compact walls. The corallites are either completely free, as
regards absolute contact, or only touch each other occasionally
at limited points, and their visceral chambers communicate
directly by means of hollow connecting-processes, into which
the tabulae are prolonged. Delicate spiniform septa are usually
present. The tabulae are well developed, more or less funnel-
shaped, and often forming an axial tube in the median line of
the visceral chamber.

The type of this family is Syringopora, Goldf , which was
placed by Milne-Edwards and Haime (Brit. Foss. Cor. Intr., p.
Ixii, 1850) with Haly sites and Thecostegites in the tribe Haly-
sitincB of the family Chcetetidce. Subsequently, the same authors,
while retaining Syringopora in the same systematic position,
associated with it the additional genera Flekkeria, E. and H.,
and CJionostegites, E. and H. (Pol. Foss. des Terr. Pal., p. 280,
185 1). The only other genera that subsequent authors have
shown a disposition to associate with Syringopora are Canna-
pora. Hall, and Aulopora, Goldf.

Of the above genera, Haly sites, Fischer, is shown conclu-
sively, by its minute structure, to have no genuine affinities
with Syi'ingopora, and must therefore be retained in the mean-

204 TABULATE CORALS.

while as the single representative of the family of the Haly-
sitidcs^ while Syringopora must be considered as the type of a
new family, for which the name of Syringoporidce may be ap-
propriately chosen. The only other form which can, in the
meanwhile, be at all definitely placed in the SyringopoiddcB is
Caunapora, Hall. The few specimens which I possess of this
singular genus — which, so far as is known, is confined to the
Upper Silurian deposits of North America — are so poorly pre-
served that I have been unable to make microscopic sections of
them, and can give no details as to their minute internal struc-
ture. Dr Rominger (Foss. Cor. of Michigan, p. 85, 1876) has,
however, examined good specimens of Ca7inap07'a juncifonnis.
Hall, the type-species of the genus, and the following generic
diagnosis is given by him : —

" Colonies of closely-approximated erect tubules, with stout
walls, sprouting from an incrusting basal expansion, formed of
prostrate tubules, growing and multiplying in the same manner
as an Aulopora. The erect ends of the tubules are annulated
by wrinkles of growth and by sharp-edged periodical offsets
marking an interruption and renewed growth from the inner
circumference of the old orifices. The sides of the tubes are
partly connected by horizontal expansions of the walls, partly
in direct contiguity, in which latter case the otherwise circular
tubes are pressed into a polygonal shape, and connect in the
contiguous parts by lateral pores. The orifices are slightly
dilated at the margins, radiated by twelve spinulose projections,
rows of which extend through the whole length of the tubes.
Diaphragms are not often developed, direct, transverse, and not
funnel-shaped as in Syringopora^

From the above description it will be evident that CaTinapora
supplies us with a very interesting link between Syringopora
and Favosiies, though upon the whole most closely allied to the
former. Cannapora closely resembles Syringopora in its habit
and general form, and the periodically-produced horizontal
expansions which connect contiguous corallites have been shown
by Rominger to be sometimes developed in Syriiigopora tabu-

SYRINGOPORID.E. 205

lata, Van Cleve. The chief distinction between Cannapoj'a and
Syringopora would, in fact, seem to consist in the possession
by the former of horizontal instead of infundibuliform tabulse.
On the other hand, Cannap07^a, Hall, approaches Favosites in
the possession of "mural pores " in those parts of the corallum in
which the corallites are in actual contact; and it maybe directly
compared with such members of the Favositid(£ as Vcrmipora,
Hall, in which a partially disjunct condition of the tubes exists.

Chonostegites, E. and H., has been shown (see supra) to be a
true member of the Favositidce closely allied to Michelinia, De
Kon., and it cannot, therefore, be associated with Syringopora.

Thecostegites^ E. and H., again, is defined as having an in-
crusting submassive corallum, composed of short cylindrical
corallites, which are united by strong mural expansions in the
form of more or less distinct horizontal platforms. The walls
of the corallites are well developed, and are only free in the
intervals between the periodic expansions just spoken of. The
calices are circular ; imperfect septa to the number of twelve
are present ; and the tabulae are distinctly horizontal (Pol. Foss.
des Terr. Pal., p. 297). The type of this genus is T. Bouchardi^
Mich., from the Devonian of Ferques in France; and Milne-
Edwards and Haime mention that they have seen specimens
from the Falls of the Ohio, and possibly from the Eifel. They
further point out that the genus has a decided affinity to Syrin-
gopora, and that it has special relations with S. tabitlata, V^an
Cleve. They give a short and very insufficient description of
a second species {T. auloporoidei) from the Devonian of Spain.
Recently Dr Rominger (Foss. Cor. of Michigan, p. 83) has
made out a strong case in favour of the view that Thecostegites
Bouchardi is really nothing more than a peculiar condition of
growth of Syringopora tabulatay Van Cleve. Dr Rominger,
however, seems to consider that the original specimens of T.
Bouchardi yN&r^ derived from the Falls of the Ohio, which is cer-
tainly not the case ; and until these specimens are re-examined,
it cannot be said that absolutely final evidence has been brought
forward in favour of the complete suppression of Thecostegites.

2o6 TABULATE CORALS.

It need only be added that if Thecostegites should prove finally
to be nothing more than a mode of growth of Syri7igopora,
then the curious little coral from the Lower Silurian of Ayr-
shire described by Mr R. Etheridge, jun., and myself (Mon.
Sil. Foss. Girvan, p. 50, 1878), under the name of T. (?) Scoti-
ctis, will have to be removed from the genus Thecostegites, with
which it will have no affinity. The coral in question, however,
though resembling the figures given of T. Boitchaj^di, E. and H.,
in general appearance, is only known from limited material, and
it throws no light on the validity or the reverse of the genus
Thecostegites.

The genus Fletcheria was founded by Milne-Edwards and
Haime (Pol. Foss. des Terr. Pal., p. 300) for the single species
F. tubifera, of the Upper Silurian of Sweden. The genus is
defined as having a corallum composed of cylindrical corallites,
which increase by calicular gemmation, and are not united
laterally either by transverse connecting-processes or by hori-
zontal mural expansions. The walls are strong, with a com-
plete epitheca ; the septa are rudimentary ; and the tabulae are
highly developed and horizontal. As in the case of Thecoste-
gites, it seems impossible to determine finally the true position
of Fletcheria without a re-examination of the original specimens,
upon which Milne-Edwards and Haime founded the genus.
Dr Lindstrom (Ann. and Mag. Nat. Hist., ser. 4, vol. xviii. p.
13) says Xki-aX Fletcheria tubifera, E. and H., "seems to be a
Cystiphylloid of very variable characters ; " but I do not know
the evidence in support of this view. Dr Rominger is disposed
to think that Fletcheria, E. and H., and Cannapora, Hall, may
be identical and closely allied ; but there seems little decided
ground for accepting this view, or indeed for in any way
associating Fletcheria with Syringopora or Cannapora. As
just remarked, it appears hopeless to try and settle the afifin-
ities of the genus without access to the type-specimens ; but
judging merely from the description and figures of Fletcheria
tubife^^a given by Milne-Edwards and Haime {loc. cit.), I
should be rather disposed to think that Fletcheria will be found

SYRINGOPORID.^. 207

to be a member of the Favositidce, and that Vermipora, Hall,
if not an actual synonym, is most nearly allied to it. The
calicinal gemmation of F. hibifcra is, however, an almost
unique feature.

Lastly, the genus Atdopora, Goldf., has been by various
palaeontologists associated with Syi'ingopoi'a, or even merged
with the latter. This view, for reasons which have been pre-
viously stated in brief, and which I shall subsequently discuss
at greater length, appears to me to be untenable ; and Aulopora
must, with our present knowledge, be regarded as the type of
a special group.

From the above remarks it will be seen that no other forms
can in the meanwhile, with any definiteness, be placed in the
Syringoporidcs , except only Syringopoi^a and Caunapora. It is
only in the case of the former of these that I have had the
opportunity of making myself thoroughly acquainted with the
minute characters of the corallum, and I shall therefore not
only take this genus as the type of the group, but I shall defer
any remarks as to the affinities of the family till I have given a
brief description of the peculiarities in its structure. Both the
above genera are strictly Palaeozoic, Caunapora being exclu-
sively an Upper Silurian form, and Syringopora being confined
to the Upper Silurian, Devonian, and Carboniferous periods.

Genus Syringopora, Goldfuss.

(Petref. Germ., t. i. p. 75, 1826.)

Harmodites, Fischer, Notice sur les Tubipores fossiles, p. 19, 1828.

Gen. Char. — Corallum commencing as a prostrate network of
tubes, which in process of growth sends up numerous vertical
corallites. The corallites are cylindrical, arranged with varying
degrees of closeness, and each enclosed in a distinct wall. The
visceral cavities of contiguous polypes communicate directly
by means of a greater or smaller number of hollow horizontal
connecting-processes, which in some cases may be nearly or

2o8 TABULATE CORALS.

quite obsolete. Tabulae well developed, usually more or less
regularly funnel-shaped, and often giving rise to a more or less
continuous tube occupying the axis of the visceral chamber.
Septa usually slightly developed, spiniform, never lamellar.

Obs. — Few genera of Palaeozoic corals are more clearly
marked out than Syj^ingopora by the general form and mode
of ofrowth of the corallum. The corallum commences as a
stoloniferous prostrate network of anastomosing tubes, which
closely resemble an Aulopora In general appearance, and have
given rise to the opinion that Aulopora is founded simply upon
young colonies of Syinngopora. The chief grounds for rejecting
this view will be briefly discussed hereafter, but there is one
consideration to which attention may here be drawn. The
prostrate network which forms the base of a colony of Syringo-
pora can be admirably studied in forms like S. fascictilaris,
Linn., of the Upper Silurian ; and in these cases we find that
there is presented to our observation the binder siwface of the
basal reticulation, as figured by Edwards and Haime in the
British Fossil Corals, PI. LXV., fig. i c. Now this under
surface of the network would, if the coral were an Attlopoi^a,
be cemented firmly to some foreign object throughout the
whole of its extent, and It would not therefore be exposed to
view at all. On the other hand, there is the clearest possible
evidence that the basal reticulation of Syringopora was not
parasitic at all, and that its under surface was quite free as a
general rule, except at one or more circumscribed points of
attachment. Whether or not the tipper surface of the basal
reticulation of a Syringopora, prior to the formation of the
ascending corallitcs, has ever been so much as actually observed,
Is a matter quite open to question. Cases In which the upper
surface of such a reticulation have been described or figured
{e.g., by Edwards and Haime, Brit. Foss. Cor., PI. LXV., fig. i)
may admit of the explanation that the observer was in reality
dealing with the colony of a true Aulopora. It seems, indeed,
in the highest degree probable that the formation of the ver-
tically ascending corallites is commenced in the very earliest

SYRINGOPORID^. 209

stages of the formation of the basal network, in which case
there is little likelihood of our ever seeing the upper surface of
the latter. Even if this were not the case, and if the basal
reticulation were really formed as a whole before the ascending
tubes began to be thrown up (as seems to have been generally
assumed), it may be stated with confidence that nothing short
of a microscopic examination of the internal structure would
suffice to show whether any given specimen were a young
Syringopora or an adult Aulopora, seeing that the macroscopic
characters would in either case be precisely the same. Upon
the whole, therefore, I cannot regard it as established that
AtUopora is founded upon the early stages of Syringopoi'a ;
nor can I accept the view propounded by Dr Lindstrom (Ann.
Nat. Hist, ser. 4, vol. xvlii. p. 14), that the connecting-tubes
which unite the neighbouring corallites of Syringopora are
" morphologically nothing but the stolons, no longer creeping
or attached, but suspended freely between the corallites."

In its fully-grown condition, the great bulk of the corallum of
Syringopora is composed of essentially cylindrical erect coral-
lites, which are placed at variable but slight intervals, and
usually diverge more or less markedly as the surface Is ap-
proached, owing to the intercalation of new tubes. The new
corallites are produced either by budding from the sides of the
old tubes or as offshoots from the transverse connecting-pro-
cesses. The walls of the corallites are thick and compact,
surrounded superficially by a delicately-wrinkled epitheca, and
sometimes strengthened internally by a secondary deposit of
finely-laminated sclerenchyma (often in S. genic2ilata, Phill.)
Whether the corallites are near or comparatively remote from
one another, their visceral chambers are placed in direct com-
munication by means of hollow, usually cylindrical, horizontal
connecting-processes. These connecting-processes (fig. 30, a)
are tubular, and the anastomosing lamellae of the tabulae from
the visceral cavity are prolonged into them. They are there-
fore to be regarded as direct outward prolongations of the vis-
ceral chambers of the polypes, and they correspond precisely

2IO TABULATE CORALS.

with the hollow transverse floors which connect the corallites
in Chojiostegites Clappi, and into which the subvesicular tabulae
are similarly extended. The number of the connecting-pro-
cesses in the dififerent species of Syringopora is very variable.
Usually they are placed at tolerably distant and to some extent
regular intervals ; sometimes they are arranged in whorls {S.
verticillata, Goldf.) ; sometimes they are greatly reduced in
number {S. se7^pens^ Linn.) ; and sometimes they are given off
in verticils at corresponding levels, and coalesce so as to form
almost uninterrupted horizontal floors {S. tabulata, Van Cleve).
In .S". nobilis, Bill., and ^. intermedia^ Nich., both from the
Devonian of North America, the erect tubes throw out lateral
buds at short intervals, but the corallites are very rarely con-
nected by horizontal processes ; and it is possibly the case that
these forms should be regarded as a distinct subgeneric type.
Lastly, in the singular ►S. laxata, Billings, also from the
Devonian of North America, the connecting - processes are
totally wanting, and the corallites are for the most part quite
free. In places, however, the flexuous and closely-set tubes
come into partial contact, and at these points they become
coalescent by their walls. That their visceral chambers com-
municate directly at these points of partial coalescence, I think
hardly doubtful, though the preservation of my specimens will
not allow me to verify this conjecture.

How far the arrangement and form of the connecting- tubes,
and the distances by which the various corallites in a colony
are separated from one another, can be employed as characters
of specific value, remains for future consideration. All that can
safely be said at present is, that too much stress has probably
been laid by the older observers upon these characters, and
that they must in reality be admitted to enjoy a considerable
variability within the limits of the same species, though they
exhibit at the same time a certain average condition, which is
by no means without its value, in each specific type.

As regards the internal structure of the corallites of Syringo-
pora, we have only to notice the condition of the tabulae and
the septa. The tabulae (fig. 30) are typically, if not always.

6" YRING OPORIDyE.

more or less conspicuously infundibuliform, and they become
connected with one an-
other in such a manner as
to give rise to a central
cylindrical tube, occupy-
ing the axis of the vis-
ceral chamber. Whether
or not this tube is present
In all the species of the
genus is a point for future
determination; but its ex-
istence is clearly recog-
nised by Goldfuss (Petref.
Germ., PI. XXV., figs.
6 b, "J b), and I have re-
cognised Its existence in
all the forms which I have
as yet examined micro-
scopically. In its general
form and structure it Is
precisely similar to the
axial tube which is form-
ed by the tabulae in the
corallltes of Syringolites,
HInde; and the continu-
ity of its internal cavity
seems to be interrupted
(as in Syringolites) by the
occasional extension of a
tabula across it. Some
forms of Syringopora are
stated to possess horizon-
tal tabulae, but the true
structure and position of these will require to be more fully
worked out before this can be finally admitted. ^

Fig. 30. — A, Part of a longitudinal section of ^'-
7-ingopora reticulata, Goldf., from the Carbonifer-
ous Limestone of Kendal, Westmorland, enlarged
five times, showing the spiniform septa and the
funnel-shaped tabulce with their central tube.
Owing to the flexures of the corallites, the section
cuts the tubes in different parts, sometimes passing
close to the wall and showing the cut ends of the
spiniform septa, sometimes passing through the
axis of the visceral chamber and bisecting the
axial tube, and sometimes cutting the axial tube
and its enveloping tabulae in an oblique manner.
B, Part of a transverse section of the same speci-
men, enlarged five times, showing the spiniform
septa, and the cut edges of the tabulte surrounding
the central tube.

1 Ludwig (Pal. des Urals, p. 10, 1862) has endeavoured to revive the genus
Harinodiies, Fisch., as distinct from Syringopoj-a, Goldf., upon the ground that

2 12 TABULATE CORALS.

The septa in Syriiigopora are usually, if not always, detected
without difficulty in thin sections, whether vertical or trans-
verse ; and their most striking feature is, that they are
thoroughly " Favositoid " in character, having the form of
slender spinules arranged in vertical rows (fig. 30). They
never extend more than a limited distance into the interior
of the visceral cavity, and they vary much in length. Not
uncommonly, also, the descending tabulae carry on their inner
faces slender spines (as in the Favositoid genus Chonostegites,
E. and H.), which seem to represent inward prolongations of
the septa. They are also variable in number, not unfrequently
exceeding twenty in a single cycle. Lastly, they are composed
of a sclerenchyma which is conspicuously lighter in tint than
that of the walls of the corallites (see PI. X., fig. 5). As the
result of this, long sections in parts where they happen to
coincide with the wall of a corallite (fig. 30, a) exhibit vertical
rows of rounded spaces of lighter colour than the surrounding
tissues, these being really the cut ends of the spiniform septa
divided near their bases, though they might at first sight be
readily mistaken for mural pores.

With regard to the affinities and zoological position of
Syringopora, a consideration of the foregoing account of its
minute structure will, I think, render it clear that the eenus
cannot be referred to the Halysitidcs^ to the Tubiporidcs, or to
the Rugosa, one or other of these courses having been gener-
ally followed by palaeontologists. From Halysiies, the genus
Syringopora is fundamentally separated by the general form of
the corallum, the entirely different construction of the tabulae,
the total absence of a set of small zooids coexisting with one
of larger dimensions, and the presence of hollow connecting-
processes placing the visceral chambers of contiguous corallites

some forms from the Carboniferous Limestone of Russia appear to have the funnel-
shaped tabulae open inferiorly, whereas they are closed in Syringopora. So far as I
understand the ambiguous language which he uses on this point, the differences
alluded to by Ludwig are of no moment whatever ; and at any rate, the forms which
he describes as Harmodites are shown by his figures to be typical species of
Syringopora.

SYEING OPORID^. 2 1 3

in direct communication. As to the recent genus Tttbipora, it
seems unnecessary to enter into any detailed discussion, as the
known facts as to the internal structure of Syringopora render
any direct affinity between the two genera wholly out of the
question. More, on the other hand, may be said for the view
so ably advanced by Dr Lindstrom (Ann. and Mag. Nat. Hist,
sen 4, vol. xviii. p. 13), that Syringopora is truly a Rugose
Coral, allied to Litkostroiion and Diphyphyllum. Even here,
however, I think that the distinguished Scandinavian palaeon-
tologist has allowed himself to be misled by resemblances which
are truly analogical and not fundamental. I am not prepared
to allow that there is any true relation of homology between
the hollow connecting -tubes of Syringopora and the also
hollow radicular processes or connecting-processes of many
Rugose Corals. Dr Lindstrom's argument on this point, if
carried to a logical conclusion, would necessitate the removal of
unquestionable Favositoid and Perforate Corals (such as Mich-
elinia, Nod2ilipora, &c.) to the Rngosa, since these also pos-
sess hollow radiciform prolongations. On the other hand, the
totally different nature of the tabulse and septa in Syringopora,
as compared with these structures in Lithostrotion and DipJiy-
p/iylhmi — to say nothing of the connecting-tubes of the former
— entirely forbids, in my opinion, any taxonomic union of forms
so diverse.

For my own part, after a careful study of the minute struc-
ture of both groups, I am satisfied that the SyringoporidcB are
properly to be regarded as an aberrant group of the Perforata,
having genuine relationships with the Favositidcs, though dis-
tinct from these. Upon this view, the hollow connecting-tubes
of Syringopora are homologically nothing more than " mural
pores," as existing in corallites which are not in absolute con-
tact. In support of this view, I would simply draw attention
to the absolute identity in the internal structure of the connect-
ing-tubes of Syringopora and the hollow connecting - floors of
Chonostcgites. Yet Chonostegitcs is a true Favositoid, with the
closest possible relations to Michelinia, De Kon. ; and wher-

214 TABULATE CORALS.

ever we find its corallites actually in contact, there we find true
" mural pores " developed, of the precise type of these structures
in Favosites itself. Nor have I much doubt that at any points
in the corallum of a Syringopora at which the corallites come
into actual contact, openings in the wall placing the body-cavi-
ties of the polypes in direct communication will be found to
exist, though I have as yet had no opportunity of verifying this
conjecture. Indeed, Rominger states that such a condition of
parts actually does exist in Cannapora, Hall, which seems to
be a close ally of Syringopora. Lastly, as supporting the
relationship between the present genus and the FavositidcB, it
may be pointed out that the singular funnel-shaped tabulae and
axial tube of Syringopora are found to exist in an almost pre-
cisely similar form in Syringolites, Hinde, a " Favositoid "
genus which possesses prismatic contiguous corallites and seri-
ally-placed " mural pores " of a form exactly similar to those of
Favosites.

So far as is known, the genus Syringopora ranges from the
Silurian to the Carboniferous inclusive, but it attains its max-
imum in Devonian and Carboniferous strata. The species
which I have at present been able to examine by means of a
proper series of microscopic sections are S. 7'eticulata, Goldf.,
S. geniailata, Phill., S. intermedia, Nich., 6^. laxata, Bill., .S.
fascicular is, Linn., and kS. bifurcata, Lonsd. ; but as I have
given a tolerably detailed account of the genus, it will be suffi-
cient to add merely very brief descriptions of the specific char-
acters and minute structure of the first two of these.

SYRING OPORID^. 2 1 5

Syringopora reticulata, Goldfuss.
(Fig. 30, and PI. X., fig. 5.)

Syringopora reticulata, Goldfi.iss, Petref. Germ., vol. i. p. 76, PI. XXV., fig. 8,

1826.
„ reticulata, Phillips, Geol. of Yorkshire, vol. ii. p. 201, 1836.

,, reticulata, Edwards and Haime, Pol. Foss. des Terr. Pal., p. 290,

1851 ; and Brit. Foss. Corals, p. 162, PI. XLVI., figs, i, i a,

1852.
„ reticulata, M'Coy, Pal. Foss., p. 84, 185 1.

„ reticulata, De Koninck, Nouv. Rech. sur les An. Foss., Part I.,

p. 123, PI. XL, figs. 7-7 ^, 1872.

Spec. Char. — Corallum fasciculate, of long cylindrical coral-
lites, the usual diameter of which is about one line. The dis-
tance at which the corallites stand apart varies very much in
different colonies, and even in different parts of the same cor-
allum, some tubes being in partial contact, while others may be
separated by intervals of two lines or more. Ordinarily they
are from half a line to a line apart. The tubes are slightly
flexuous, but not abruptly geniculated ; and the irregularly-
distributed connecting-tubes are about two lines apart, or
rather less than this. Well -developed spiniform septa are
present, the wall is not thickened by secondary deposit, and
the tabulae are infundibuliform, and give rise to the formation
of an axial tube.

Obs. — This is one of the most characteristic of the species of
Syringopora in the Carboniferous Limestone of Britain, and
the above diagnosis embodies its most noticeable structural
features. As regards its internal structure, cross-sections (fig.
30, B, and PI. X., fig. 5) show that the walls of the corallites,
though of tolerable thickness, have no secondary deposit of
sclerenchyma in their interior; while the spiniform septa are
well developed, and are arranged In about twenty or twenty-
four rows. The cut edges of the infundibuliform tabulse are
exhibited in sections of this kind as so many concentrically-
disposed or spirally-arranged lines surrounding the transverse-

2i6 TABULATE CORALS.

ly-divided axial tube. In long sections (fig. ■x^o, a) the septa
present different appearances in different parts of the slide
(precisely as in Favosites), according to the inclination of the
plane of the section as regards the axial plane of the corallite.
Where the section cuts through the axis of the visceral cham-
ber, the septa are only seen as lateral spines directed inwards
from the bounding walls of the tube ; where the section is to
any extent excentric, the cut ends of the spiniform septa come
into view as rows of circular spots ; and where the section
coincides with the wall of the corallite, the cut bases of the
septa look like rows of light spots in the darker-tinted scleren-
chyma which surrounds them (see fig. 30, a). The most strik-
ing feature in long sections, however, is that of the infundibuli-
form tabulae arranoed in a succession of invacrinatinof cones,
which give rise centrally to a distinct axial tube. This axial
tube seems to be intersected by occasional prolongations of
the tabulae inwards ; and owing to the flexuous condition of the
tubes, it is never laid open continuously for any distance. On
the contrary, any long section, as a rule, cuts the axial tube
over and over again with varying degrees of inclination, so
that we are presented with repetitions of the obliquely-divided
tube, surrounded by the cut edges of the concentrically-dis-
posed ensheathing tabulae. Lastly, both long and cross sec-
tions show that the connecting-processes afford a direct com-
munication between the visceral chambers of contiguous tubes,
and that the progressive walling off of the visceral cavities of
the polypes by the production of tabulae is accompanied by an
extension of these structures into the connecting-processes, as
these are successively rendered useless. It only remains to
add that Milne-Edwards and Haime speak of this species as
being remarkable (Brit. Foss. Cor., p. 163) *' for the existence
of a delicate transverse lamina which passes through the con-
centric infundibula, and is shown by a transverse section of the
corallum ; " but I can find no traces of such a structure, and
do not feel sure if I rightly understand what structure they
refer to.

SYRING OPORID^. 2 1 7

Formation and Locality. — Abundant in the Carboniferous
Limestone of Kendal, Shap, Cross-Fell, Red-Hills, and other
localities in Westmorland and Cumberland.

Syringopora geniculata, Phillips.

(PI. X, figs. 4-4^.)

Syringopora geniculata, Phillips, Geol. of Yorkshire, vol. ii. p. 201, PI. II.,

fig. I, 1836.
,, geniculata, M'Coy, Syn. Carb. Foss. of Ireland, p. 190, 1844;

and Brit. Pal. Foss., p. 83, 185 1.
„ geniculata, Milne-Edwards and Haime, Pol. Foss. des Terr. Pal.,

p. 291, 185 1 ; and Brit. Foss. Cor., p. 163, PI. XLVL, figs. 2,

2 a, and 4, 1852.
„ geniculata, De Koninck, Nouv. Rech. sur les An. Foss., PI. XL,

fig. 8, and XII., fig. 2, 1872.

Spec. Char. — Corallum fasciculate, of long, diverging, close-
set, cylindrical, thick-walled tubes, which are enclosed in a
thick wrinkled epitheca, and are usually rather less than one
line in diameter. Connecting-tubes numerous, having no reg-
ular distribution, and usually placed at distances apart of one
line or less, though sometimes more remote. Wall often
thickened by a dense laminated secondary deposit of scler-
enchyma. Septa short and spiniform. Tabulae numerous,
infundibuliform, and giving rise to an axial tube. Distance
between the corallites variable, but mostly half a line or less.

Obs. — This species is commonly associated with the preced-
ing in the Carboniferous Limestone, and is usually easily to be
distinguished from it by the more marked divergence of the
corallites from the base of the colony, their closer approxima-
tion to one another, their more conspicuously round tubes, their
thicker walls, and the greater abundance of the connecting-
processes, together with the rather smaller diameter of the
corallites. The specific name would indicate that the tubes
were markedly geniculate ; but this is by no means the case,
and the corallites resemble those of S. reticulata, Goldf., in
being simply flexuous. In all the principal features of its

21 8 TABULATE CORALS.

internal structure, S. geniculata, Phill., agrees entirely with
S. reticulata, and it is unnecessary to dwell upon the pheno-
mena exhibited by thin sections. There is, however, one
curious character, of very common though apparently not uni-
versal occurrence, in which 5". genictdata is quite peculiar. One
of the most striking features, namely, in 6". geniculata, is the
apparent thickness of the walls of the tubes ; and thin trans-
verse sections show that this is really due to the fact that the
proper wall is liable to become lined by a dense, finely-lamin-
ated secondary deposit of sclerenchyma (see PI. X., figs. 4 a
and 4 b). This secondary deposit is of a markedly darker
colour than the true wall, which, along with the short spini-
form septa, can be thus easily recognised. In this peculiarity,
►S. geniculata, Phill., bears to the ordinary forms of Syringopora
the same relation that Pachypora and its allies bear to Favosites.
This same thickening can often be recognised in long sections
(PI. X., fig. 4), but I have not been able invariably to recognise
its existence, and I am disposed to think that it is probably
present only in certain parts of the tubes (as is the case in
Pachypora and in some related forms), or that it depends
upon age.

Formation and Locality. — Common in the Carboniferous
Limestone of Shap, Kendal, Asby, Ravenstonedale, and other
localities in Westmorland.

219

CHAPTER IX.

AULOPORIDyE.

This family can only be treated very briefly, partly because the
materials at present in my possession are insufficient for its
complete elucidation, partly because these materials have not
yet been fully examined, and partly because the small size and
parasitic habit of the type-forms give rise to special difficulties
in the way of their satisfactory examination by means of thin
sections. The genus Attlopora, Goldfuss, with its ally Clado-
chonus, M'Coy (= Pyrgia, E. and H.), was originally referred
by Edwards and Haime to a special division of Zoantharia, to
which the name of Z. Ttibulosa was given. This division was
stated to be characterised (Pol. Foss. des Terr. Pal., p. 310,
1 851) by the fact that the corallites are pyriform and destitute
of " tabulae," and the septa are represented only by vertical
striae, while the walls of the thecse are wholly imperforate ; but
the undoubted presence of tabulae in typical forms of Aulopora
removes the only ground for the retention of the Tubulosa as
a distinct division of Zoaiitharia. The corallum in Aulopora
(fig. 31, d) has the form of a creeping, branched or reticulate,
system of tubes, attached by the whole of the lower surface
to the exterior of a shell, coral, or other foreign body. The
basal and prostrate stolons send up tubular or trumpet-shaped
corallites at longer or shorter intervals ; but though the ter-
minal portions of these are free, the length of the tubes is al-
ways very limited, and the reclined corallites never grow up
into a fasciculate mass. The walls of the corallites are quite

220

TABULATE CORALS.

compact, and the tubes are for the most part not in contact
with one another in any part of their extent. In cases, how-
ever, where the tubes come into contact to any extent, it may

Fig. 31. — A, Two Q)^s.va^\e?> o{ Cladocho7!iis Michelini, E. and H., from the Lower Carbonif-
erous of Dunbar, of the natural size ; B, A small example of the same, enlarged five times ;
c, A longitudinal section of the same species, enlarged five times; D, Portion of a colony
oi Aulopora, sp., from the Devonian (Hamilton Group) of Ontario, of the natural size ;
E, Longitudinal section of part of the same, enlarged five times ; F, Cross-section of a
corallite of the same, enlarged five times, showing the tabulse ; G, Portion of a colony of
Aulopora rcpens, E. and H., from the Devonian of the Eifel, of the natural size; H,
I.,ongitudinal section of part of the same, enlarged seven times, showing curved tabulse,

not impossibly be found that " mural pores " exist at the points
of union. The septa are always quite rudimentary, in the form
of marginal striae or vertical rows of tubercles. Lastly, the
continuity of the visceral chamber is interfered with (in certain
species at any rate) by complete transverse tabulee (fig, 31, e, f,
and n), which are usually more or less curved, or even funnel-
shaped, but which do not appear to give rise to anything
resembling the axial tube of Syringopora.

The resemblance between the colonies of Aulopora and the
basal portions of a Syringopora, as regards general aspect, has
been already pointed out ; but there is, nevertheless, no suffi-
cient reason, in my opinion, for uniting the two. The reasons
for this belief have been already given, but may be briefly sum-

AULOPORWyE. 221

marised as follows: i. The colonies oi Aulopora are parasi-
tic, the whole of their lower surface being attached to foreign
bodies ; whereas the similar-looking basal reticulation of Sy-
rtjigopora was clearly attached only at one or two limited
points, the greater part of its under surface being free. 2.
The curved and reclined corallites of Atilopora are free only at
their terminations, and they do not give origin to erect branches ;
whereas the basal network of Syringopora throws up numerous
erect corallites from its upper surface, and it has not been shown
that the network has any existence apart from the erect tubes
to which it gives origin. 3. The connecting - tubes of Sy-
ringopoi''a are not known to be represented by any correspond-
ing structures in Attlopoi^a. 4. The tabulae of Atilopora are
simply curved, or, if infundibuliform, do not appear to give rise
to any structure comparable with the axial tube of Syringopora.
5. Species of Sy7dngopora abound in formations where the
genus Aulopora is hardly or not at all represented, while
colonies of the latter are common in deposits in which
SyrmgoporcB are nearly or quite unknown.

For the above reasons, I am at present unable to accept the
union of Aulopora with Syringopora, as advocated by some high
authorities. At the same time, there are one or two species
now referred to Syriiigopora (such as S. serpens, Linn., of the
Upper Silurian) which have marked " Auloporoid" characters,
and which may prove on minute examination to be really
referable to the Auloporidcs .

To Romingeria, Nich. i^ — Quenstedtia, Rom.), the present
genus bears considerable external resemblance ; and if Rom-
inger is right in regarding Atdopora corntita, Bill,, as only the
young of Romingeria, this resemblance would seem to be based
upon real affinity. As far as our present knowledge goes, how-
ever, we are constrained to separate Romingeria from the
Auloporidcs, as it possesses "mural pores" in parts, while it
further differs from Aulopora proper in having an erect
corallum.

As regards its geological range, the genus Atdopora seems

222 TABULATE CORALS.

to appear for the first time In the Lower Silurian period, and
is well represented in the Upper Silurian. In the Devonian
period it attains its maximum of development, and a few Car-
boniferous species are known ; but the latter are rare and local
in their distribution, and the genus is not known to have sur-
vived into the Permian period.

The genus Cladochomis, M'Coy, was proposed In 1847 (Ann.
and Mag. Nat. Hist., ser. i, vol. xx. p. 227) for some Aus-
tralian Palaeozoic corals, having " some relations to Atilopora,"
but differing^ " in their curious erect habit, reg-ular angrular mode
of branching, slender, equal, stemlike tubes, and abruptly-dilated
terminal cups bent in nearly opposite directions." He further
states that the curious little Carboniferous corals which he had
formerly referred to Lamoroux's genus J^ajiza (Syn. Carb. Foss.
of Ireland, 1844) are really to be placed in the genus Clado-
chonus. There seems, further, to be no reasonable doubt that
the genus Pyrgia, Edwards and Haime (Pol. Foss. des Terr.
Pal., p. 310, 185 1), is really founded upon forms oi CladocJiomis,
M'Coy, and that it must therefore be withdrawn in favour of
the latter. My friend Mr R. Etheridge, jun., and myself have
prepared a paper^ dealing with the structure and relations of
some of the forms of Cladochoitus, and we find that besides
species which may be retained in Cladochoniis, the genus con-
tains at least one very peculiar type (viz., C. crassiis, M'Coy),
which must be considered as generically distinct, and to which
we have given the name of Monilopora crassa, M'Coy, sp. In
a typical species of Cladochonus, such as the Carboniferous C.
{Pyrgia) Michelini, E. and H., the corallum has the form of a
slender erect branching colony, composed of long conical coral-
lites (fig. 31, A and b), which are produced from one another by
lateral budding, the entire growth being fixed basally to some
foreign object by one or more Isolated points of attachment.
An excellent description of this singular coral is given by De
Koninck (Nouv. Rech. sur les An. Foss., p. 153, PI. XV., fig.

^ Since the above was wriUen this paper has been published {see Geol. Mag.,
Dec. ii. vol. vi., July 1S79).

AULOPORID^. 223

6, 1872), and this accurate observer states that the visceral
chambers of the corallites are entirely hollow, and that they
communicate freely with one another by their bases. This
latter point is doubtless correct ; but Mr R. Etheridge, jun.,
and myself have made thin sections of specimens from the
Carboniferous of Scotland which we are unable to distinguish
from C. Michelini, E. and H., and we find that in these the
visceral cavities of the corallites are intersected by a few
remote, delicate, complete tabulse, which are either straight or
slightly curved (fig. 31, c). It would appear, then, that so far
as at present known there is nothing in the internal structure
of Cladochomts, M'Coy {^ Pyrgia, Edw. and H.), which would
separate it from Atdopora, Goldf , and the generic distinctness
of the two can only rest upon the feature that the corallum of
the former is erect, whereas in the latter it is creeping and
parasitic. So far as known, the species of Cladochonus appear
to be exclusively Carboniferous.

Lastly, it remains to say a few words upon the singular
genus Monilopora, Nich. and Eth. jun., which includes only
the curious il/. [Cladochonus) crassa, M'Coy, sp., of the Carbon-
iferous rocks. In this singular form the corallum (fig. 32, a) is
decidedly "Auloporoid" in its general appearance, consisting of
a creeping tubular basis, which at intervals throws up curved
conical corallites, which are of much larger size than is usual in
Aulopora, and are free throughout the whole or the greater part
of their height. As a rule, the corallum commences in the form
of a ring of such corallites, with their connecting basal stolons,
encircling the column of a Crinoid like a necklace ; and by the
continued growth of the latter the colony often becomes entirely
buried within the stem of the Crinoid, only the calices appear-
ing on the surface. Adult examples, again, often lose a good
deal of this ring-like arrangement, and present themselves as a
confused aggregation of corallites quite resembling a magni-
fied Aulopora. The minute structure of Monilopora, as eluci-
dated by means of thin sections, has been shown by Mr
Rofe (Geol. Mag., vol. vi. p. 352, 1869), and subsequently

224

TABULATE CORALS.

more fully by Mr R. Etheridge, jun., and myself, to be of a
most remarkable character. The entire visceral cavity of each
polype is open from top to bottom, and we have been unable to

Fig. 32. — A, A full-grown co\o\\y o{ Motiilopora a-assa, M'Coy, sp., growing upon the stem of
a Crinoid, of the natural size. B, A younger colony of the same, encircling a Crinoidal
column, viewed from above, of the natural size, c, A detached fragment of the corailum
of the same, of the natural size. D, Transverse section of a young colony of the same
growing upon a Crinoidal column, enlarged two and a half diameters. (The visceral
chambers of the corallites are largely filled with matrix, and the peculiar reticulated tissue
of the skeleton is here and there visible in the wall, while the whole has been finally en-
veloped by the growth of the stem of the Crinoid.) E, Longitudinal section of a single
corallite of the same, enlarged five diameters, showing the open visceral chamber, the
fibrous wall, and the reticulated structure of the wall of the calice. F, A portion of the
reticulated tissue still further enlarged. Carboniferous Limestone of Lancashire (British
Museum.)

detect any traces of tabulae (fig. 32, d and e). The wall of the
theca is exceedingly thick, and throughout the greater part of
its extent it seems to consist wholly of delicate concentric layers
of sclerenchyma firmly united with one another. In parts of
the corallite, however, and especially as the calice is approached,
the concentric lamellae of the wall become separated from one
another, so as to include a series of distinct interspaces or
cavities, which are approximately parallel to the axis of the
visceral chamber, diverging slightly outwards, and which are

AULOPORIDyE. 225

crossed at right angles by numerous delicate cross-bars or tra-
beculee of sclerenchyma (fig. 32, e and f). This extraordinary
reticulate tissue is present in the calicine wall of all specimens
of Monilopora crassa which have hitherto been examined, but
no similar structure is known to occur in any other coral, nor
does it seem possible to offer any probable suggestion as to its
functions or homologies. Apart from this unprecedented fea-
ture, Monilopora can only be separated from Aulopora by the
total absence of tabulae, such as exist in, at any rate, some of
the latter, if not in all.

As to the affinities of the Atiloporidce, it appears hazardous
at present to give any definite opinion. If I am right in refer-
ring Syringopora to the Perforate Corals, then it would not
appear that the present group can have any 7^eal alliance with
the Syringoporidce ; and its relationship with any other division
of " Tabulate Corals " would seem to be even more remote.
Perhaps the most probable conjecture is that which would look
upon the AtiloporidcB as a peculiar group of the Alcyonaria.

226

CHAPTER X.

HALYSITID^ AND TETRADIID^.

HALYSITID7E.

The group of the HalysitidcB constituted, in the system of
Milne- Edwards and Haime, a sub-family {Halysitince) of the
family ChcstetidcB, and it contained the five genera Halysites,
Syringopora^ ThecostegiteSy Chonostegites, and Fletcheria. The
last four of these have been already treated of; and there re-
mains, therefore, only the genus Halysitcs itself as the type and
sole representative of the family, which may be defined as com-
prising coralla composed of long cylindroidal tabulate corallites,
which are always more or less extensively united with one
another, but have imperforate walls, and exhibit neither mural
pores nor connecting-tubes. Spiniform septa may or may not
be present, and there may or may not be two diverse sets of
corallites. As the family comprises only the single genus
Halysites, any remarks as to its systematic position will be best
deferred until the characters of the genus have been discussed.

Genus Halysites, Fischer, 1813.

(Zoognosia, 3d ed., t. i. p. 387.)

Catefiipora, I.amarck, Hist, des An. sans Vert., t. ii. p. 206, 1816.

Gen. Char. — Corallum fasciculate and reticulate, composed of
long tubular cylindroidal corallites, which are placed side by side
in intersecting and anastomosing lamince or lines, any given cor-

HALYSITID^ AND TETRADIID^. 227

allite beinor united alone: its whole leno^th with its neicrhbours to
the right and left, and each lamina of the corallum consisting
of no more than a single linear series of tubes. Each tube is
enclosed in a strong imperforate wall surrounded on its free
sides by a thick epitheca, and there is usually a distinct divi-
sion of the corallites into two series of different sizes, in which
case a single small tube is placed between each pair of the
larger tubes. Septa may be obsolete, and, when present, have
the form of vertically-disposed rows of spines in cycles of
twelve. The tabulae are well developed, complete, not in-
fundibuliform nor vesicular, the smaller tubes (when present)
being more closely tabulate than the larger ones.

Obs. — The general form of the corallum in Htily sites is con-
stant in all the known species of the genus, and is too well
known to need special description. Every corallite in the
corallum, except those which form the ^ctual circumference, is
united along its whole length, along opposite sides, to two other
corallites, those which form the centre of three of the constitu-
ent laminae of the mass being similarly united to three of their
neighbours. This union is, moreover, not one of mere contact,
but is absolute, the epitheca and wall of any given tube being
directly continuous with the corresponding structures in the
tubes which stand to the right and left of it (PI. XI., fig. i).
The most extraordinary feature in the organisation of Haly-
sites, however, concerns the mode by which the lateral union of
the ordinary corallites of Haly sites is effected. If we make a
thin transverse section of the form usually known as H. eschar-
oides, Lam. (PI. X., fig. 6), we find, as just remarked, that the
epitheca and walls of neighbouring tubes are absolutely con-
tinuous ; but we observe, further, that the epitheca does not take
any part in the formation of the partition which actually divides
any tube from its neighbour on either side. On the contrary,
the partition in question is formed solely by the coalescent watts
of the two contiguous corallites, and it is always of a lighter
colour and apparently less compact texture than the rest of the
tube. We have, therefore, here the singular fact that each tube

2 28 TABULATE CORALS.

is enclosed by the epitheca only on its two free sides. In the
form known as H. escharoides, Lam., all the tubes are of ap-
proximately equal size ; but if, on the other hand, we make a
thin transverse section of an example of the typical H. catenu-
laria, Linn., we shall find a still more interesting and curious
condition of parts (PI. X., fig. 7, and PI. XI., fig. i). In these
cases the epitheca and proper walls of the corallites are directly
continuous (as in H. escharoides), but there is now the additional
feature that between each pair of the normal corallites there is
intercalated a much smaller sub-quadrate tube, which forms the
medium of union between the former. This interstitial tube,
moreover, does not seem to be bounded laterally by an inward
prolongation of the walls of the large tubes (as one would
expect it to be), but it appears to be enclosed by a proper
and peculiar wall of its own on the two sides where the large
tubes on either side come against it ; and this proper wall is
at once distinguished under the microscope from the wall of
the large tubes by its much darker colour and seemingly differ-
ent texture (see PI. XL, fig. 1). There are thus shown to
exist two distinct sets of corallites in H. catenularia, Linn.,
which occupy fixed and invariable relations to one another,
and can be proved by long sections to possess a marked differ-
ence in internal structure. Thus the large or normal corallites
of this species (PI. X., fig. 8, and PI. XL, i a) have curved
or nearly straight complete tabulae, regularly and comparatively
remotely disposed. On the other hand, the small interstitial
tubes are intersected by much more numerous and more closely-
set tabulae, which are sometimes straight and sometimes sub-
vesicular, the condition of parts thus closely resembling what
is observed in the large and small corallites of Heliolitcs and its
allies.^ In Haly sites eschai'-oides, as we have seen, the small

* So far as I know, Hall first noticed the occurrence of the small closely tabulate
tubes between the larger ones, as he says, in his description oi H. agglomerata, that
the " spaces between the tubes" are " cellular" (Pal. N.Y., vol. ii. p. 129, 1852), and
he clearly figures the closely tabulate intermediate tubes. The first clear and at all
complete account of this subject appears to have been given by Fischer-Benzon in a
paper, " Ueber Halysites," to which I have unfortunately been unable to obtain

HALYSITIDJE AND TETRADIID^. 229

interstitial tubes — so far as my observations go — seem to be
wanting ; but I have never failed to recognise their existence
in H. catemdaria, Linn. ; and they are especially well developed
in all specimens of H. agglomerata, Hall, which I have ex-
amined.

With regard to the septa of Haly sites, the condition of parts
varies greatly in different forms of the group. In those forms,
namely, which are usually referred to H. catenularia, Linn., I
have never succeeded in recognising in microscopic sections
any traces whatever of septa, except that the lateral walls of
the intermediate or small corallites often carry small projec-
tions apparently of a septal nature (PI. XL, fig. i). On the
other hand, in the forms which are usually known as H.
escharoides, Lam., there are always well -developed spiniform
septa, of exactly the same type as in the Favositidcs and
SyringopoiHdiS. These septa are arranged in vertical rows,
the number of which seems to be constantly twelve in each
corallite.

I do not intend here to give any description of any of the
species of Halysites, especially as I am unable to make up my
mind as to the true relations of H. cafenuiaria and H. eschar-
oides to one another. Till now I have ventured to differ from
such distino-uished authorities as Milne-Edwards and Haime,
and have always considered these as mere varietal forms, since
I have looked upon the sole alleged differential characters —
viz., the size of the tubes and the dimensions of the meshes of
the corallum — as purely varietal characters. By means of micro-
scopic sections, I have satisfied myself — so far as my material
goes — that the form known as H. escharoides, Lam., is distin-
guished from the typical H. catenularia, Linn., not only by
the superficial characters just mentioned, but also by the con-
stant possession of spiniform septa, and the apparently constant
absence of small tubes between the larger one. As these dif-

access, but this observer does not seem to have recognised the true nature of the
interstitial tubes. To Dr Lindstrom, therefore, is due the credit of having pointed
out that the corallum oi Haly sites, as of Heliolites, consists of two distinct sets of
zooids (Ofversigt af Kongl. Vetenskaps Akad. ForhandL, 1873).

230 TABULATE CORALS.

ferential characters are fundamental ones, It may seem ridicu-
lous to doubt any longer the specific distinctness of H, escJiar-
oides and H. catemdaria. The two forms, however, are so re-
markably similar in most respects, are so variable in external
characters, and are so constantly associated together, that I am
still almost disposed to conjecture that they are the different
conditions of a dimorphic species, and that their differences
are due to something else than specific distinctness.

As regards the affinities and zoological position of Halysites,
the above account of its structure leaves little doubt that the
genus is more nearly allied to the Heliolitidce than to any
other. Halysites agrees with Heliolites and the recent Helio-
pora in possessing (usually) two distinct sets of corallites, large
and small, the two being distinguished further by the arrange-
ment of their tabulse ; and there can be no reasonable doubt
that this indicates that each colony of the typical H. catemdaria,
Linn., consisted of two structurally and functionally distinct sets
of zooids. On the other hand, I cannot accept the view of Dr
Lindstrom (Ann. Nat. Hist., sen iv., vol. xviii. p. 13), who
actually places Halysites among the HeliolitidcB. It appears
to me, on the contrary, to form a quite special group, distin-
guished from Heliolites and its allies, not only by the unique
form of the corallum, but also by the great reduction, or, it
may be, total absence, of the smaller zooids, by the frequent
absence of septa, and by the fact that the septa (when present)
are spiniform, and present no resemblance to the "pseudo-septa"
of the HelioporidcE. If the view that Halysites is nearly allied
to the Helioporidce be accepted, then it follows that the family
of the HalysitidcE will have to be considered as a distinct and
ancient group of the Alcyonaria ; but it will still remain certain
that no true relationships have been shown to exist between
Halysites and the Ttibiporidcs, with which family the genus has
often been associated.

The geological range of Halysites, so far as known, is an
extremely limited one, the first representatives of the genus
appearing in the later portion of the Lower Silurian period.

HALYSITIDyE AND TETRADIID^. 231

while the maximum development of the genus is attained in
the Upper Silurian, and no Devonian species has been as yet
detected.

TETRADIID^.

This group includes only the Silurian genus Tetradmin,
Dana, and its probable systematic place will be best discussed
after some description of the genus has been given. The
fullest account of the genus which has yet been published is
one which was given by Mr R. Etheridge, jun., and myself
(Ann. and Mag. Nat. Hist., sen iv., vol. xx. p. 162, 1877) ; and
the following brief analysis of the chief characters of Tetradium
is for the most part extracted from the memoir just referred to.

Genus Tetradium, Dana, 1846.
(Wilkes's Expl. Exped. Zoophytes, p. 701.)

Gen. Char. — Corallum massive, composed of long prismatic
and closely contiguous corallites, the walls of which are not
pierced by mural pores or other foramina. The septa are
distinct, few in number, most typically four, short, not reach-
ing the centre of the visceral chamber, and seeming as if
formed by inflections of the wall. Calices generally petaloid,
as are the corallites in transverse section. Tabulae numerous,
complete. Increase apparently by fission of the old tubes.

Obs. — The genus Teh^adium was founded by Professor Dana
for the reception of a fossil of uncertain locality in the collection
of Yale College, New Haven ; and the following characters were
ascribed to it : " Coralla massive, consisting of four-sided tubes
and cells, with very thin septa or parletes ; cells stellate, with
four narrow laminae."

At a subsequent date. Professor J. M. Safford described four
species of corals from the Lower Silurian Rocks, which he re-
ferred to this genus (Amer. Journ. Sci. and Arts, ser. 2, vol.
xxii. p. 236) ; and he supplemented Dana's description with

232 TABULATE CORALS.

the following remarks : " The tubes in the different species
vary from one quarter of a line to nearly one line in breadth ;
they are very long, and are most frequently united throughout
laterally, forming massive coralla, resembling more or less those
of Favosites and Chcetetes ; sometimes, however, they are united
in single intersecting series, as in Halysites catefiulata, Linn. ;
not unfrequently, too, the tubes are isolated, or only united at
Irregular intervals, thus forming loose fasciculated coralla, re-
sembling certain forms of Syringopora."

Professor Safford further states that the isolated tubes are
nearly quadrangular, with more or less rounded angles, and
with a slight external longitudinal depression opposite to each
of the four septa ; the walls are more or less rugose ; and in-
crease is by fission of the old tubes. Only one specimen was
seen in which tabulae could be detected ; and in this they were
confined to one end of the mass, and were distant from one
another about twice the width of the tubes.

The genus TeU^adium is regarded by Safford as Intermediate
between the Favositidcs and the Ricgosa, the quadripartite char-
acter of the corallites placing it in the latter group.

Taking such a well-known species as the Z! minus, Saff , of
the Cincinnati Group, as the type of the genus Tetradium, we
find that the corallum (fig. 33, a) Is massive, hemispherical,
or irregular in shape, and composed of closely amalgamated,
slender, prismatic corallites, which diverge from the base or
from an imaginary axis, and are not arranged in superimposed
layers. No general epitheca seems to be present. The coral-
lites are in close contact throughout their length, and their walls
appear to be entirely imperforate. Some doubt, however, must
in the meanwhile remain upon this point, owing to the fact that
all the microscopic sections I have made (of specimens derived
partly from Ohio and partly from Canada) show the walls to have
undergone a very peculiar change. The walls of the corallites,
namely — though the specimens appear otherwise to be quite
unaltered — have the normal granular carbonate of lime which
composes the Coelenterate skeleton replaced by ciystalline cal-

HALYSITID.^ AND TETRADIID.^.

233

cite. Hence we could hardly hope to detect mural pores, even
if such structures had at one time existed. For the same reason
it must remain doubtful whether or not the walls of contiguous
);orallites are actually amalgamated with one another. Mr
Etheridge and myself arrived at the conclusion that the walls
were really double (as in Favosites) ; but we based this opinion
chiefly upon the apparent exposure of the exterior of the
tubes In some fractured specimens, and I have subsequently
seen reason to think that the appearances in question are not
constant. I still think that the walls are really double ; but as
the microscopic evidence is not conclusive, I can only leave the
point an open one.

The most characteristic feature in the corallum of Tetradiimi,
which separates it, even to superficial inspection, from that of
a massive ChcBtetes, is the conspicuously cruciform or petaloid
form of the calices or of transverse sections of the corallites
(fig. 33, b). This petaloid form is due to the presence of four
delicate lamellar septa, which look as if formed by inward fold-

Fig. 33. — A, Fragment of a large corallum of Tdraditini minus, Safford, from the Cincinnati
Group of North America, of the natural size ; B, Transverse section of the same, enlarged
ten times, showing the petaloid form of the tubes and the short septa ; c, Vertical section
of the same similarly enlarged, showing the tabulae.

ings of the wall, and which extend for a short distance only
towards the centre of the visceral chamber. Normally, and
most generally, four of these septal laminae are present, but
their number is not constant, and varies from one to five.
The only other special point brought out by sections is, that

234 TABULATE CORALS.

the visceral cavities of the polypes are intersected by numer-
ous complete tabulae, which are straight and horizontal, and
entirely independent of each other (fig. 33, c).

As regards the systematic position of Tctradium, the known
peculiarities in its structure seem to render three conclusions
more or less certain : (i) That Safford's conjecture as to the
Rugose affinities of the genus is entirely untenable ; (2) that the
genus has no strong points of relationship with Chcetetes, which
it most nearly resembles in general form and habit ; and (3) that
its true alliances are with Halysites and Heliolites. As regards
Halysites, the chief points of likeness are to be found in the
fact that both genera possess remarkably long tubular imper-
forate corallites, and in the fact that both Safford and Billings
have indicated that specimens of Tetradium sometimes assume
the otherwise unique habit of Halysites, the corallites being
united by their lateral margins in single intersecting series. I
have never myself been so fortunate as to meet with any speci-
mens exhibiting the peculiar mode of growth just alluded to,
but it is evident that whatever may be the relationship between
Tetradium and Halysites — and I do not doubt that there is a
relationship — the former genus is widely separated by its lamel-
lar, not spiniform septa, by the cruciform arrangement of these
structures, and by the total absence of any set of small zooids
coexisting with those of normal size. On the other hand,
Tetradium presents a very striking resemblance to Heliolites
in the form of the delicate lamellar septa, which have every
appearance of being "pseudo-septa" produced by inflection of
the wall. The absence, however, of small zooids, would of
itself be quite sufficient to prevent any actual reference of
Tetraditim to the Helioporidce, even if other differences (such
as in the number of the septa) did not exist as well. Upon the
whole, therefore, it seems best to regard Tetradium, Dana, as
the type of a special group of the Alcyonaria, allied to the
HalysitidcE and the Helioporidcs, and yet distinct from both of
these.

235

CHAPTER XL

THECID^ AND HELIOPORID^.

THECID^.

The group of the Thccidce, E. and H., comprises only the
anomalous Silurian genus Thecia, E. and H., the type of which
is the Thecia Szvmdernana of Goldfuss. It is important to
bear this fact in mind, as I shall found the following descrip-
tion of the group entirely upon a most careful macroscopic and
microscopic investigation into the structure of the type-species
of the genus, of which I possess a large number of authen-
tic examples, derived from the Wenlock Limestone of both
Britain and Sweden. I mention this the more particularly
here, because it is needless to say that the diagnosis of a genus
must in all cases be ultimately decided by the structural char-
acters of the original type of that genus, and cannot be based
upon forms which any given observer may believe, perhaps
upon insufficient grounds, to be congeneric with that type.
The genus now under consideration illustrates this point in
an especial manner, for the last, and in all respects the most
circumstantial, account of the genus Thecia, E. and H., which
has yet been published (Foss. Cor. of Michigan, p. 65, 1876),
ascribes to the genus characters such as do not exist in the
type-species, and ignores other fundamental features which are
really present in the latter ; and I do not think that so accom-
plished an observer as Dr Rominger could have arrived at

236 TABULATE CORALS.

some of his conclusions, unless it were that some of the forms
which he refers to Thecia are really of a different nature.

The affinities of the family of the ThecidcB will be best con-
sidered after I have given a short account of the structural
characters of the genus Thecia ; and the group may be in the
meanwhile defined as including coralla formed of tubular
corallites of two distinct sizes, the larger disposed with con-
siderable regularity among the smaller ones. The large coral-
lites are tabulate, with indistinctly differentiated walls, provided
with obtusely triangular and irregular septa, and having their
visceral cavities more or less freely connected with one another
by lateral horizontal channels, which penetrate the interstitial
tubular tissue. The smaller interstitial tubes are doubtfully
tabulate, and their cavities are liable to be largely filled up by
a secondary deposit of sclerenchyma.

Genus Thecia, Edwards and Haime, 1849.
Comptes Rend., t. xxix. p. 263.

Gen. Char. — Corallum rarely ramose, usually in the form of a
laminar expansion, covered below by a concentrically wrinkled
epitheca, and having the calices placed upon its upper surface.
Corallites in the main erect and perpendicular to the horizontal
axis of the corallum (sometimes slightly curved inferiorly), of
two sizes, large and small. The large corallites are placed at
regular intervals, and though their visceral chambers are clearly
circumscribed, they cannot be said to be bounded by distinctly
differentiated walls ; but they are, on the contrary, embedded
in a dense tissue composed of the smaller tubular corallites,
which may open on the surface by means of irregular, often
stelliform apertures, or may be to a large extent closed by a
secondary deposit of sclerenchyma. The smaller corallites are
primitively bounded by distinct polygonal walls, and it is not
certain if they are tabulate. On the other hand, the large
corallites are distinctly tabulate, are provided with irregular

THECID.^ AND HELIOPORID^. 237

and obtuse lamellar septa, and communicate directly with one
another by means of tortuous horizontal channels passing from
one to another. No columella is present.

Obs. — Owing to the great density of its tissues, the diffi-
culties in the way of making a thorough examination of the
structure of Thccia by means of the microscope ^ are unusually
great, and it has been only by means of a large series of thin
sections that I have been enabled to come to any satisfactory
conclusions as to its minute anatomy, while there still remain
some points of importance which I have found it impossible to
clear up. The corallum in the type-species, T. Swindernana,
Goldf. sp., has the form of a laminar, usually discoid expansion,
attached by the centre of its base to some foreign body, and
having the whole of the lower surface covered by a concentri-
cally striated and wrinkled epitheca. The upper surface carries
the calices, and when examined macroscopically, even by means
of a lens, usually shows nothing but the stellate apertures of
the larger corallites, which are from a third of a line to half a
line in diameter, and are separated by what appears to be an
equal width of dense interstitial tissue. This interstitial tissue
is marked superficially by numerous minute, radiating, often
vermicular grooves, which extend from each calice to the neigh-
bouring ones (PI. XI., fig. 2), and it was regarded by Milne-
Edwards and Haime as being of the nature of a " spurious
ccenenchyma, resulting from the intimate union of the costae "
(Brit. Foss. Corals, p. 278). As there are no costee in Thecia,
Milne- Edwards and Haime were, of course, in error in suppos-
ing this interstitial tissue to be formed by the coalescence of
structures of this nature ; but in the sense in which they used
the term " ccenenchyma," they were undoubtedly right in
supposing that they were dealing here with a " coenenchymal "
tissue. In other words, there can be no doubt as to the identity
of the interstitial tissue of Thecia with the so-called " ccenen-

1 Though in the habit of preparing all my own sections for the microscope, I was
compelled in this instance to have resort to the skill of Mr F. G. Cuttell; and I have
therefore had the advantage of probably the most beautiful sections of this difficult
form which could be prepared at the present day.

238 ' TABULATE CORALS.

chymal tubuli " of Heliolites and its allies, which we only know
by the quite recent researches of Moseley to be not truly of a
coenenchymal nature. When, in fact, we examine exceedingly
thin sections of Thccia, whether these be either transverse or
longitudinal, we find that the apparently dense and compact
tissue which seems to separate the large corallites is in truth
composed of vertical tubules, which we must now regard —
from what we know of the Helioporid<^ — as being properly
small corallites, tenanted by a special set of zooids. So far,
then, the structure of TJiecia is essentially identical with that
of Heliolites, but there are some very important differences to
be observed in these types respectively. In Heliolites and its
relatives, both the larger and the smaller corallites are enclosed
by thin but perfectly distinct walls, the former having well-
developed septa and remote tabulae, the latter having no septa
and crowded tabulae ; while there is no sufficient evidence of
any lateral communication between the visceral cavities of the
larger corallites. In Theeia, on the other hand, the large coral-
lites cannot be proved, even in the thinnest sections, to possess
any proper wall, their boundaries not being clearly separable
from the dense tubes of the interstitial tissue ; the septa which
they possess are not at all similar to the thin inflections of the
wall which constitute the " pseudo-septa " of Heliolites and its
allies, but are thick and irregular ridges ; while the interstitial
tubuli — so far as can be certainly ascertained — are destitute of
tabulae. There is, moreover, the curious feature that the larger
corallites are placed in direct communication by means of dis-
tinct, often tortuous, horizontal channels, which traverse the
interstitial tubuli.

If we examine a thin transverse section of Theeia Swinder-
naiia under the microscope (PI. XL, figs. 2 a, 2 b), we observe
that the visceral chambers of the large corallites are quite dis-
tinctly marked out, though nothing of the nature of a differen-
tiated bounding- wall can be detected. Here and there the
visceral cavities of two contiguous polypes may be seen to be
directly connected by a horizontal canal, which happens to have

THECID^E AND HELIOPORID.E. 239

been placed in the plane traversed by the section. The septa
appear simply as blunt, triangular, irregular lateral ridges, with
ill-defined margins, having deep sulci at their bases, but always
leaving a considerable central area into which they do not pene-
trate. The interstitial tissue presents different appearances in
different parts, or under different conditions of preservation.
Sometimes — though by no means always — the interstitial tissue
can be recognised as divided into a number of small polygonal
areas by a network of dark lines, which represent the primitive
walls of the interstitial tubuli. Often these walls can only be
recognised by the slightly thickened nodes at their angles of
junction, or they may not be capable of detection at all. In the
same way, the minute central cavities of the interstitial tubuli
may appear in cross-sections as so many minute, irregular,
sometimes stelliform apertures, or they may be filled with
granular sclerenchyma, when the interstitial tissue appears
to be wholly solid.

In longitudinal sections (PI. XI., figs. 2 c, 2 d), the visceral
cavities of the larger corallites are distinctly marked out, as
before, without any clearly-defined wall, and are seen to be
intersected by well - developed complete tabulae, which are
slightly flexuous, and sometimes anastomose to some extent
with each other ; while occasionally the section exhibits a
portion or the whole of one of the horizontal canals placing
contiguous tubes in communication. In sections of this nature,
the composition of the apparently dense interstitial tissue out
of numerous closely-approximated vertical tubuli can always
be recognised without the slightest difficulty. Moreover, these
tubuli, In sections of sufficient thinness, can always be recog-
nised as being bounded by perfectly distinct, apparently double
walls ; but their cavities appear to be more or less extensively
obliterated by a deposit of granular, not laminated sclerenchyma,
which seems, however, to be very irregularly distributed. No
tabulae can be detected, though it is possible that such struc-
tures really existed.

From a consideration of the above characters, it will be

2 40 TABULATE CORALS.

evident that Dr Lindstrom had much ground for his suggestion
(Ann. Nat. Hist., sen 4, vol. xviii. p. 13) that Thecia is closely
allied to the HeliolitidcB. As has been already pointed out,
however, there exist certain very important differences between
Thecia and Heliolites, which are of too fundamental a nature to
permit of our associating these genera in a single family. Of
these differences, the most important is the presence in the
former genus of distinct and well-developed horizontal canals,
which traverse the interstitial tissue, and place the visceral
cavities of neighbouring polypes in direct communication This
feature is one in which the genus approaches the Perforate
corals in general, and the Favositidce in particular ; but the
latter are fundamentally distinguished by the total absence of
anything analogous to the interstitial tubuli of Thecia. Upon
the whole, therefore, the best course to follow is to place Thecia
in a distinct family — Thecidcs, E. and H. — which will occupy a
position in the Alcyoiiajda close to the HelioporidcE ; and in so
doing we may remember that though the horizontal canals
above spoken of recall to our minds the " mural pores " of
the Favositidcs and the hollow *' connecting-processes " of the
Syringoporidcs^ the existence of a direct connection between
the visceral cavities of neighbouring polypes is a common
feature in the Alcyonarian Zoophytes. Before leaving the
subject of the affinities of the genus Thecia, a few words may
be said as to the views which Dr Rominger has expressed upon
the same point (Foss. Cor. of Michigan, p. 65). According to
this observer, Thecia has "the general structure oi Tavosiies ;''
the walls of the corallites are thick, and are bounded by " de-
fined polygonal outlines," but occasionally " the walls do not
exceed in thickness those of an ordinary Favosites ;" the septa
are spiniform, and extend nearly to the centre of the visceral
chamber; and "large and abundant" lateral pores {i.e., mural
pores) are present. The figures given by Dr Rominger, beauti-
ful as they are, being heliotypes, present the specimens of the
natural size, and give one no clue as to their real internal struc-
ture. Not having seen Dr Rominger's specimens, it would be

THE CI D^ AND HELIOPORID^. 241

useless to criticise his diaenosis of the o-enus in detail. I can
only say, therefore, that the structure of the type-species, T.
Swindernana, Goldf. sp., as above described, is such as to render
it apparently impossible that the forms ascribed to Thecia by
Dr Rominger can really be congeneric with it. In fact, Thecia
Swindernana does not agree in any important respect with
Thecia as defined by Dr Rominger, and especially differs in the
characters which I have above enumerated. If Dr Rominger,
therefore, has not been misled by the examination of specimens
greatly altered by fossilisation, it is clear that the species de-
scribed by him under the name of Thecia must belong to some
other generic type. Lastly, Dr Rominger asserts that Pi'ot-
arcEa, E. and H., possesses corallites which have mural pores,
and are provided with convex tabular, and that it is a near ally
of Thecia. On this point, I can only say that I have failed to
discover any traces of tabulze in Protarcea, either in actual
specimens or in thin vertical sections ; that though the walls
are porous, there are no " mural pores," properly so called, in
any examples I have seen ; and that I am unable, therefore, to
accept the view that any alliance exists between this genus and
Thecia.

So far as at present known, the genus Thecia is confined in
its geological range to the Upper Silurian rocks, the type-
species, T. Swindernana, Goldf., being an abundant and charac-
teristic fossil of the Wenlock Limestone of Britain and Sweden.

Helioporid^ (Moseley).

This well-defined and distinctly circumscribed group of corals
is characterised by the possession of a corallum composed of
two distinct sets of corallites, tenanted in life by two distinct
sets of zooids. The larger tubes are uniformly distributed
among a very much larger number of much smaller ones, and
are provided with delicate lamellar septa ("pseudo-septa"),
which are formed by infoldings of the wall, are typically twelve
in number, and are occasionally rudimentary or even obsolete.

Q

242

TABULATE CORALS.

The visceral cavities of the polypes are also crossed by com-
plete, more or less horizontal tabulse. The smaller corallites
are typically provided with distinct walls, which may, however,
be rudimentary ; and they have their internal cavities intersected
by horizontal or strongly convex tabulse, while septa are en-
tirely wanting. No lateral channels exist in any of the fossil
forms (so far as known), by which the visceral cavities of the
larger corallites are placed in communication with one another,
or with the cavities of the smaller corallites.

From the researches of Mr Moseley (Phil. Trans., vol.
clxvi p. 92, 1876), we know that Heliolites and its allies are
essentially similar as regards the structure of the corallum to
the living Heliopora, and we have therefore the right to con-
clude that this resemblance extended to the soft parts as well.
We have therefore every right to conclude \\\2X. Heliolites and
its relations were Alcyonarian Zoophytes, with polypes of two
different kinds, the fully-developed zooids inhabiting the larger
tubes of the skeleton, and having eight mesenteries and eight
pinnately-fringed tentacles ; while the septa do not correspond
in number with the mesenteries, and are consequently to be
regarded as " pseudo-septa." The only important point in
which Heliolites and the forms related to it appear to differ
from Heliopora is that the cavities of the small sexless zooids
of the latter genus are stated by Mr Moseley to communicate
directly with the body-cavities of the larger corallites ; but we
have in the meanwhile no evidence of the existence in the
extinct genera of any apertures in the walls of the larger
corallites by which such a communication could be effected.
This difference, if ultimately established, will be one of great
importance ; but a further examination of the fossil forms will
be required to prove conclusively that the large zooids pos-
sessed no direct communication with the smaller ones.

The genera included in this family are the Palseozoic^ Helio-

^ The Devonian genus Batiersbyia, E. and H. (Pol. Foss. des Terr. Pal., p. 227),
originally placed by its founders in the neighbourhood oi Heliolites, has been shown
by Professor Martin Duncan (Phil. Trans., vol. clvii., 1867) to be a member of the
special family of the PalastrcEactcr, an extinct group of the Zoantliaria Aporosa.

THECID.^ AND HELIOPORID/E. 243

litcs, Dana, Plasmopora, E. and H,, Propora, E. and H., Pinaco-
pora, Nich. and Eth. jun., and Lycllia, E. and H., the Cretaceous
Polytreniacis, D'Orb., and the recent Heliopora, De Blainv., of
which only the first five concern us here. Fistulipora, M'Coy,
which has often been inchided among the HeliolitidcE, appears
to me, for reasons which will subsequently be given, to belong
rather to the ChcBtetidce (or to the Montiadiporida;, if such a
family be ultimately established), and I shall consider it in
association with Constellaria and Monticulipora. The Palaeozoic
genera of the HelioporidcB are exclusively Silurian and De-
vonian, and there is such a close similarity in their general
structure that they require but comparatively brief notice.

Gemts Heliolites, Dana, 1846.

(Wilkes's Expl. Exped. Zooph., p. 541.)

(PI. XII., figs. 2-2 a.)

Gen. Char. — Corallum spheroidal, pyriform, hemispherical,
or rarely ramose, composed of numerous closely contiguous
corallites, which are divisible into two distinct series. The
larger corallites are cylindrical, comparatively few in number,
and furnished with twelve lamellar infoldings of the wall, of
the nature of pseudo-septa, which fall short of the axis of the
visceral chamber. Small corallites completely investing the
larger ones, more or less regularly polygonal in form, provided
with distinct walls, which are completely amalgamated with one
another and with the walls of the larger tubes, and which are
not known to be provided with any apertures allowing lateral
communication. The small tubes have no septa, but have
numerous straight and complete tabulae, similar but somewhat
less numerous structures existing in the large tubes. No
columella.

Obs. — The corallum in Heliolites is usually more or less
hemispherical or spheroidal in shape, the under surface covered
with a concentrically-striated epitheca, and having the calices

244 TABULATE CORALS.

opening over the whole upper surface. In other cases {e.g., II.
Grayi, E. and H.) the corallum is ramose or lobate, fixed by
its base, and having the cahces covering the whole of the free
surface. The internal structure of the corallum can be readily
studied in actual specimens or in polished sections, and little
fresh information is afforded by thin slices. The most impor-
tant points to notice, as differentiating the genus from its im-
mediate allies, or as otherwise of interest, are the following : —

The corallites are univers3.11y and throughout in complete
contact, their walls being so entirely amalgamated that no
traces of their originally duplex constitution can be detected.
No apertures of the nature of "mural pores" are known to
exist in the walls.

The walls of the larger corallites are folded so as to give rise
to twelve septal ridges, which are continuous from the top to
the bottom of the visceral chamber, and are not spiniform. In
some cases {e.g., H. megastoma, M'Coy) the septa are marginal
and rudimentary (PI. XII., fig. 2) ; in other cases they extend
inwards for a considerable distance ; but in no case do they
actually meet in the centre of the visceral chamber. No septa
exist in the smaller corallites.

The number of the smaller corallites varies much in different
species, but there is always enough of them to completely
isolate the larger tubes. Usually there are several layers of
small tubes between any given pair of the larger tubes, but
there are only from two to five rows in H. rnegastoma, M'Coy ;
and there are usually no more than two rows, or only a single
one, separating the larger corallites in H. dubia, Fr. Schmidt,
and in H. plasjiioporoides, Nich. and Eth., jun.

The smaller corallites of Heliolites are principally distin-
guished from the corresponding tubes in Pi'opora and Plasmo-
pora by their regularly polygonal shape, and by the fact that
their walls are never obsolete, but are completely developed
(PI. XII., fig. 2 a). In long sections, therefore, no difficulty
is experienced in recognising the walls of the smaller tubes.

The tabulae are well developed in both the larger and

THECID^ AND HELIOPORID^. 245

smaller corallites (PI. XII., fig. 2 a), and in thin sections appear
to be of a much darker colour than the actual walls of the
tubes. In the small corallites the tabulae are numerous, com-
plete, more or less horizontal, and often placed at corresponding
levels in contiguous tubes. In the larger corallites the tabulae
are also complete, and essentially horizontal, but they are
placed at somewhat greater distances apart, and they occasion-
ally unite with one another.

I have made an examination by means of thin sections of
H. interstincta, Linn., H. Mttrchiso7ii, E. and H., H. megastoma,
M'Coy, H. porosa, E. and H., and H. Gi^ayi, E. and H. ;
but none of these depart in any noticeable feature from the
normal type of the genus, or exhibit peculiarities of such
importance as to justify special description. The most aber-
rant species of the genus which I have examined is a form from
the Devonian of Australia, which will be subsequently de-
scribed by Mr R. Etheridge, jun., and myself under the name
of H. plasmoporoides, and which nearly approaches the genus
Plasnwpora by its comparatively irregular and comparatively
few interstitial tubes. It shows itself, however, to be a true
Heliolites by the complete walls of the smaller corallites, and
by the fact that the tabulae of these tubes are not curved or
vesicular. Another curious type is the Upper Silurian H.
dubia, Fr. Schmidt, but I have had no opportunity of investi-
gating this species microscopically.

So far as at present known, all the species of Heliolites are
confined to the Lower and Upper Silurian rocks, and to the
Devonian.

Genus Plasmopora, Edwards and Haime, 1849.

(Compt. Rend., t. xxix. p. 262.)

(PI. XL, fig. 5, and PI. XII., fig. i.)

Gen. Char. — Corallum discoidal when young, but becoming
hemisiDherical or spheroidal when adult, its lower surface covered

246 TABULATE CORALS.

by a concentrically-striated epitheca, while the upper surface
carries the calices. Corallites in complete contact throughout,
divisible into two distinct series. The larger tubes are com-
paratively few in number, and possess twelve lamellar septa,
formed by infoldings of the wall, and extending but a short
distance into the visceral chamber ; while they are crossed by
horizontal, complete, and comparatively remote tabulae. The
smaller tubes are devoid of septa, are comparatively irregular
in form, and only possess distinctly differentiated walls when
young. In their adult state their walls become amalgamated
with the convex and anastomosing tabulae by which their
cavities are intersected, in such a manner that they can no
longer be recognised as distinct structures, and the interspaces
between the larger corallites become filled up with a loose
tissue composed of irregular lenticular vesicles.

Obs. — In almost all the essential features of its anatomy,
Plasmopora entirely resembles Heliolites, and it is only neces-
sary here to make a few remarks on the sole character by which
the two genera can be separated — namely, the peculiar struc-
ture of the smaller tubes. In Hcliolites, as we have seen, the
smaller corallites are polygonal in shape, have perfectly distinct
walls, and are crossed by essentially horizontal tabulse, which,
though often placed at the same level in neighbouring tubes,
do not actually coalesce with one another laterally. In very
y onng s'pQcimQns oi P/asmopora petaliformis, E. and H., — the
only species of the genus that I have examined by means of
thin sections — -the condition of parts is so far like that of
Heliolites that the walls of the smaller corallites are perfectly
recognisable (PI. XII., fig. i) in long sections ; but there is this
difference, that the tabulse are now very highly convex, and are
either continued into one another, or are joined with the walls
of the tubes in such a manner as to give rise to an apparently
continuous vesicular tissue, which fills all the spaces between
the lareer corallites. In older coralla this amalo^amation of the
curved and inosculating tabulae with the walls of the tubes has
gone so far, that the latter almost or quite disappear. Hence,

THECID^E AND HELIOPORIDyE. 247

when we examine tangential sections of the corallum (PI, XI.,
^to- 5)' we find that the polygonal and comparatively regular
tubes of Heliolites are replaced by quite irregular spaces, of
very variable size, surrounded for the most part by curved
boundaries, which represent the cut edges of the component
vesicles of the interstitial tissue.

With the exception of the imperfectly characterised Plasmo-
pora micropora (Goldfuss), E. and H., which is believed to be
from the Devonian of the Eifel, all the species of this genus
are Silurian in their range.

Ge7ius Propora, Edwards and Haime, 1849.

(Compt. Rend., t. xxix. p. 262.)

(PI. XL, figs. 3-3^.)

Gen. Char. — Corallum discoidal, hemispherical, or irregularly
spheroidal, the lower surface covered with a concentrically-
striated epitheca. Corallites of two sizes : the larger ones with
distinct walls, which are infolded so as to form twelve short
septal ridges, the visceral chamber being intersected by com-
paratively remote, complete, approximately horizontal tabulae.
Smaller corallites with altogrether obsolete walls, these struc-
tures being undistinguishably amalgamated with the convex
tabulae, so that the narrow interspaces between the larger tubes
become filled up with a vesicular tissue formed of lenticular
cells. Calices slightly exsert.

Obs. — I am quite disposed to agree with Dr Lindstrom
(Ann. Nat. Hist, sen 4, vol. xviii. p. 16) in thinking that
Propoi'a can hardly be kept generically distinct from Plas-
inopora. The mere fact that the larger corallites are slightly
exsert can hardly be regarded as of generic importance ; and
an examination of thin sections of Propora tubtdata, E. and
H., has led me to take a different view of the condition of the
septa to that propounded by Edwards and Haime. These
high authorities believed that the twelve short septa of the

248 TABULATE CORALS.

larger corallltes were prolonged exteriorly into " costal " (Pol.
Foss. des Terr. Pal., p. 223); but I do not think that any
structures to which this name could be properly applied are
really present. On the contrary, I believe that the apparent
" costae " are in reality — as also in Plasmopora — nothing more
than the imperfectly-developed walls of the smaller interstitial
corallites. In the structure of the large corallites, Propora
differs in no respect from either Heliolites or Plasmopora;
and as regards the smaller corallites, the condition of parts
is very similar to that which we have seen to exist in the
latter genus. I have not had the opportunity of examining
very young specimens of Propora iubulata; but if we look
at a thin longitudinal section of an adult example (PI. XI.,
fig* 3 ^)^ we see that the interspaces between the larger coral-
lites are occupied by a vesicular tissue, composed of lenticular
vesicles of different sizes, closely resembling the vesicular tissue
of a Cystiphyllum in general aspect. This tissue resembles that
oi Plasmopora, except that the vesicles are more regular in form;
and I entertain no doubt but that it is similarly formed by the
lateral anastomosis and confluence of the convex tabulae of the
interstitial tubes or small corallites, with the resulting oblitera-
tion of their walls. The walls of the small corallites, in fact,
can occasionally be very partially detected, though more usually
they have entirely disappeared as distinct structures. Similarly,
when we come to examine thin tangential sections of Propora
(PI. XI., figs. 3 and 3 a), we see that the narrow interspaces
between the comparatively close-set large corallites are occu-
pied by rows of irregular spaces, bounded by dark lines.
These lines, however, are not " costae," but are the cut edges
of the lenticular vesicles formed by the coalescence of the
curved tabulae with the walls of the small corallites. Ordin-
arily there is but a single row of small corallites between each
pair of large ones, though sometimes two rows are present.
(In long sections, as in PI. XL, fig. 3 b, there commonly
appears to be quite a wide tract of vesicular tissue between
two contiguous large tubes ; but this, of course, is only due

THE CI D.^ AND HELIOPORID.E. 249

to the fact that the section has happened here to traverse
a line lying between several of the larger corallites.)

Accepting the above views as to the true structure of the
corallum of Propora, it seems clear that the genus agrees in
substantial characters with Plasmopora, with which therefore
it should be united. The species which have been referred
here are Upper Silurian in their range. (The supposed Car-
boniferous species is a Palcuacis.)

Gcmis Lyellia, Edwards and Haime, 1851.

(Pol. Foss. des Terr. Pal., p. 226.)

(PI. XL, figs. 4, 4 a-)

Geii. C/iar. — " Corallum massive ; corallites cylindrical, with
thick and costulated walls, free towards their terminations, and
united throughout the remainder of their length by a very
abundant vesicular coenenchyma ; visceral chambers traversed
by somewhat irregular tabul£e ; septa twelve in number, well
developed " (Edwards and Haime, loc. cii.)

Obs, — The genus Lyellia was founded by Edwards and
Haime to include two species of corals (Z. Americana and
L. glabra) from the Upper Silurian of North America. Other
species of the genus have been described by Dr Rominger
(Foss. Cor. of Michigan, p. 14), from deposits of the same
age ; and it is probable that some of the forms of Heliolites
{e.g., H. affinis and H. speciosus) described by Mr Billings
from the Lower and Upper Silurian deposits of Anticosti,
are really referable to Lyellia (Cat. Sil. Foss. of Anticosti,
pp. 5 and 30). I have not myself been so fortunate as to
meet with any examples of this genus, and am therefore
able to say nothing as to its minute internal structure.
Judging from the descriptions and figures of the above-
mentioned authors, Lyellia would seem to be nearly allied
to Plasmopora, and especially to those forms of the genus
which have been usually separated under the name of Pro-

2 50 TABULATE CORALS.

pora. The conversion of the smaller corallites into a mass
of lenticular vesicles, and the round form of the larger coral-
lites (PI. XL, fig. 4 a), render this resemblance especially
noticeable. The large corallites, however, appear to be more
markedly free towards their upper ends, and the openings
of the smaller tubes upon the surface do not appear to be
conspicuous or even recognisable (PI. XI., fig. 4).

Dr Rominger, in his diagnosis of the genus, adds the
further character that the septa are composed of " vertical
rows of spinules." This of itself would go far to separate
the genus from Plasniopoi^a and Heliolites, in which the septa
appear to be always lamellar.

Genus Pinacopora, Nich. and Eth., jun., 1878.

(Mon. Sil. Foss. of Girvan, Fasc. i., p. 52.)

(PL XII, figs. 3 - 3 ^.)

Gen. Char. — " Corallum composite, coin-shaped, of extremely
short corallites supported upon the upper convex surface of a
free, discoidal, concavo-convex, concentrically striated epitheca.
Corallites of two sizes, regularly alternating with one another.
Large-sized corallites disposed in obliquely decussating rows,
each completely surrounded by a circle of very much smaller
corallites (' coenenchymal tubes'), rarely more than a single
row of these latter, however, intervening between any given
pair of the larger tubes. Large tubes furnished with twelve
short septa, in the form of blunt spiniform projections ; small
tubes without septa. Large tubes furnished with one or two
tabulae, or rarely more, situated close to their base, the upper
portion of the tube being open. Small tubes furnished with
from two to four strong and complete tabulae, which extend to
close to their summits. Large tubes circular or oval in shape ;
small tubes irregular in shape. No mural pores. No colu-
mella."

Obs. — The above generic diao^nosls Is taken from the Mono-

THECIDyE AND HELIOPORID.E. 251

graph of the Sihirian Fossils of Girvan (Fasc. I.), by Mr R.
Etheridge, jun., and myself, in which the only known species of
the genus — viz., P, Grayi, of the Upper Silurian rocks of Ayr-
shire— is fully described. As I have no further material of this
species in my hands, I shall content myself on the present occa-
sion with the following brief remarks, most of which are taken
from the work just alluded to.

The corallum in Pinacopo7'a is free, and has the form of a
thin circular exj^ansion, the under surface of which is covered
with a concentrically-striated epitheca (PI. XII., fig. 3). The
epitheca is always symmetrically concave, and its upper convex
surface (PI. XII., fig. 3 a) carries the corallites, which are re-
markable for their extreme shortness, when we take into
account their comparatively large size. Thus in a specimen
one inch in diameter the height of the corallites is only about
half a line, while the diameter of the larger tubes is equal to
their height. The corallites are divided into two groups, the
relations of which to each other are remarkably uniform. The
larger corallites are arranged upon the upper surface of the
epitheca with great regularity in obliquely intersecting rows,
each individual tube being isolated and separated from its
fellows by a zone of the smaller tubes (PI. XII., fig. 3 b).
Usually but one single row of the small corallites intervenes
between any given pair of the larger tubes, but occasionally
and here and there a few extra interstitial tubes may be
developed. The large corallites, except in their extreme
shortness, are constructed upon the type of the correspond-
ing tubes in Heliolitcs and its allies, the resemblance between
the two being especially manifest in the presence in each of
twelve short septa (PI. XII., fig. 3 d). As in Hcliolites, the
smaller corallites are wholly destitute of septa. Considering
the very limited vertical development of the corallites, the
tabulae may be said to be well developed, and they differ
in their arrangement in the large and small tubes respec-
tively. In the former, the tabulae (PI. XII., figs. 3 c and
3 e) are confined to the bottom of the visceral chamber.

252 TABULATE CORALS.

and there is generally but one of these structures present,
though two or three may be developed, in which case they
are very closely approximated. In the smaller corallites the
tabulae are more numerous (PI. XII., fig. 3 e), and they extend
to close upon the summit of the tubes. No traces, lastly, of
mural pores, or of any other apertures, in the well-developed
walls of either the larger or smaller corallites have hitherto
been detected.

As regards the systematic position of Pinacopora, there can
be no doubt that it belongs to the family of the Heliopoi'idcs,
and that Its nearest relationships are with Heliolites itself. It
agrees with Heliolites in the essential structure of the large
corallites, and also in the more important features exhibited by
the small tubes. The latter. It is true. In their comparatively
limited development, remind us of Plasmopoi-a {^Proporci) tubu-
lata, E. and H., the regular distribution of the large corallites
being another feature of resemblance between the type just
mentioned and the present form. On the other hand, there is
the fundamental difference that the walls of the small corallites
in Pinacopora are completely differentiated, while their tabulae
do not become vesicular. In these features, Pinacopora agrees
with Heliolites, from which it differs in the fact that the cor-
allum constitutes a thin, concavo-convex, leaf-like plate, not
attached to foreign bodies ; in the extraordinary shortness of
the corallites ; in the comparatively rudimentary condition of
the septa ; in the very regular arrangement of the large coral-
lites ; and in the peculiar arrangement of the tabulae in the
large and small tubes respectively. As before remarked, the
only described species of this genus is found in deposits of the
age of the Upper Silurian, in Ayrshire.

253

CHAPTER XII.

CH/ETETID^ AND MONTICULIPORID^.

Using the name ChcEtetida: in the wide and general sense in
which it has been usually employed, and temporarily including
under this title the genus Monticulipora and its allies, we
find that the group now under discussion comprises massive,
ramose, laminar, or encrusting corals composed of contiguous
tubular corallites, which are intersected by complete tabulae,
and are destitute of mural pores. There are either no struc-
tures of the nature of septa, or, at most, mere rudiments of
such. All the corallites may be like one another, or the
corallum may be composed of two distinct and differing sets
of tubes.

The ChcBtetidiE were regarded by Milne- Edwards and
Haime as a " tribe " of the Favositidce, and the genera Chcstetes,
Fischer, Dania, E. and H., Stenopora, Lonsd., and Constellaria,
Dana, were regarded as constituting this division (Brit. Foss.
Cor. Introduction, p. Ixi, 1850). Monticzclipora, D'Orb., was
originally included by Edwards and Haime under Chcstetes,
but they subsequently admitted its generic distinctness (Brit.
Foss. Con, p. 264, Note, 1854). The genus Fistidipora,
M'Coy, on the other hand, was placed by the French observers
in the family of the Millcporidce, in the immediate neighbour-
hood of Heliolites. In their great work, the ' Polypiers
Fossiles des Terrains Palseozoiques,' Milne - Edwards and
Haime established the three additional genera Beaumojitiay
Dekayia, and Labeckia, which they placed in the Chcstetince ;

254 TABULATE CORALS.

and in his last important work upon the corals (Hist. Nat. des
Cor., i860), M. Milne- Edwards adhered substantially to the
above arrangement, except that Stenopora, Lonsd., is now not
regarded as a well-characterised type.

In the sense in which it is here employed, the family
ChcEtctidcE corresponds in the main with the " tribe " ChcetetiiicB
of Edwards and Haime. Stenopora, Lonsd., is, however, now
placed among the FavositidcB ; Labechia, E. and H., is regarded
as the type of a special group ; and Fistulipora, M'Coy, and
Prasopora, Nich. and Eth., jun., are temporarily added to the
family, to take their proper place beside Monticttlipora. Thus
constituted, it must be at once admitted that the family is an
artificial and unnatural assemblage, the retention of which, as a
single group, can only be defended upon the ground of our at
present imperfect knowledge of the structure and real relations
of many of the forms included in it. It is clear, indeed, that
the forms here provisionally associated under the family
ChcetetidcB agree with one another only in the general fact that
they possess coralla composed of closely contiguous corallites,
which are without septa, are traversed by tabulae, and have
imperforate walls. This last character, however, cannot be
regarded as sufficiently established for all the forms now under
consideration. Some of them almost certainly possess noth-
ing of the nature of the " mural pores " of the FavositidcB, and
none of them have been actually proved to possess openings
of a similar nature to the above. It is not impossible, how-
ever, that some of the genera at present placed in the ChcEtetidce
may yet be demonstrated to possess " mural pores ; " and I
have myself examined a coral from the Wenlock Limestone of
Dudley, which is closely similar to Alojiiiczilipora, D'Orb., in
form and general appearance, but in which the walls are in-
dubitably porous. Moreover, an examination of the minute
structure of the forms here included under the CJicetetidcB
renders it clear that they admit of separation into two groups,
of very different size, and perhaps of a very different nature.
In the one group — which we may speak of as the Chcstetidcs

CH.^TETID.E AND MONTICULIPORIDJi. 255

proper — we have only the forms which properly constitute the
genus CIi(rtetes, Fischer (as typified by C. radians, Fisch., and
exclusive of the Monticuliporcs). These forms possess corallltes
of one kind only, which are completely amalgamated by their
walls, and which possess comparatively few and remote tabulae.
In the other group we have all the forms Included under the
genera Monticulipoi^a, D'Orb., Fistulipora, M'Coy, Dckayia,
E. and H,, Constellaria, Dana, and Prasopora, Nich. and Eth.,
jun., in all of which the walls of the corallites are not fused
with one another, and there Is mostly the important feature
that the corallum is composed of two distinct classes of coral-
lltes, Indicating the existence during life of two distinct kinds
of zooids. The corals of this latter group I shall speak of
collectively as the Monticuliporidce, though I do not at present
feel justified In finally removing them from the vicinity of the
ChcetetidcB proper, as there are a few forms generally referred
to Montiadipora In which the corallites are homomorpJiic , and
in which the corallum only differs from that of Chcetctes, In Its
most restricted sense, in the fact that the corallites are not
united by their walls.

As regards the affinities of the Chcetetidce and Monticuli-
poiddcs anything that can be said at the present moment can
be regarded as, at best, little more than conjecture. So far as
Chcetetes proper is concerned, I do not at present see that we
have any sufficient ground for supposing that we have to deal
in it with anything but a group of genuine Actinozoa. The
association of Chcetctes with the true Favositidce, as proposed by
Milne-Edwards and Haime, must certainly be rejected, as there
is no evidence to hand of the existence of perforations in the
walls of the former, and there are other Important differences as
well. At the same time, the general structure of ChcEtetes is
entirely that of the Corals rather than of the Polyzoa, and there
Is a very close resemblance to such forms as Tetradium, Saff ,
the only essential difference between these two types being the
possession by the latter of definite septa. When, however,
we come to ask more particularly as to the precise place of

2 56 TABULATE CORALS.

ChcBtetes among the Actinozoa, it becomes abundantly clear
that we have no sufficient data upon which to found a final
conclusion. All that can be said is that the genus seems to
have nearer relationships with the Halysitidce and Teti'adiidcB
among the Palaeozoic " Tabulata " than with any others, and
that we may therefore suppose, with some probability, that it is
really an ancient type of the Alcyonaria.

Still greater difficulties surround the attempt to definitely
fix the place of the Monticidiporidce^ in the zoological system.
Within late years there has been a strong tendency among
palaeontologists to relegate the fossils in question to the Polyzoa,
and a good deal of evidence — some of which will be referred to
subsequently — has been brought forward in support of this
view (see especially the admirable paper by Dr Lindstrom on
the affinities of the Anthozoa Tabulata in the ' Annals of
Natural History,' 1876). The chief ground for the proposal
to refer Monticidipora and its allies to the Polyzoa is found in
the resemblance between the ramose Monticuliporcs and the
Polyzoan genus Heteropora, De Blainv., and it must be ad-
mitted that the mere general likeness between these two types
is extremely close. External similarity, however, is an unsafe
guide in dealing with questions of zoological affinity, and such
evidence as I have at present in my hands leads me to believe
that there is in reality no relationship beween Mojiticulipora
and Heteropora. The latter of these types is best known as
occurring in the Tertiary deposits as a fossil, but I possess a
large and well-marked recent form from New Zealand, nearly
allied to H. pustulosa, Busk, and H. tort His, Lonsd., which I
have submitted to Mr Busk, and which this eminent authority
has pronounced to be new. In this interesting species, as in
the extinct forms of the genus, the polyzoary is ramose and
calcareous (fig. 34), and consists of long, tubular, thin-walled
cells, which radiate from the imaginary axis of the branches to
open on the surface by round apertures. The walls of the cells
appear to be imperforate, though in some forms of the genus
(//. Icsvigata, D'Orb.) they are pierced by minute foramina ;

CH^TETJJD.^ AND MONTICULIFORID.E. 257

nor are any traces of transverse partitions or " tabula; " to be
detected. Between the true cells, and more or less completely
separating them from one another, are numerous smaller " in-

Fig. 34. — A, Fragment of an undescribecl living species oi Ilcteropora, from New Zealand, of
the natural size; and B, Surface of the same, enlarged (original); C, Surface of a branch
of Heteropora suhretictdata, from the Tertiary, enlarged (after Reuss).

terstitial tubes," which in this particular form appear to have
their mouths unrestricted by any partial diaphragm, and which
nearly equal the true cells in point of size. It is the presence
of these interstitial tubes which gives to Heteropora its very
close superficial resemblance to the ramose species of A'loiiti-
cidipora and Fisttilipora. Not only is the nature of these
tubuli still obscure, but they present the curious feature that
they exhibit (in some cases at any rate) structures which, to
say the least of it, admit of comparison with the " tabulae " of
Monticulipora. Many or all, namely, of the mouths of the
"interstitial tubes" of some species of Heteropora are closed
by a delicate transverse partition or lid, which is perforated in
its centre by a small aperture, and is placed a little below the
lip of the opening. Sometimes these " hymen-like lids," as
shown by Prof. Busk, are periodically produced at successive
stages of growth, and thus come to simulate " tabulae." In
Heteropora elavata, Goldf , the same distinguished observer has
also shown that the mouths of the interstitial tubes commonly
exhibit a stellate appearance, owing to the projection into their
interior of delicate vertical lamellce, which simulate the " septa "
of the true corals.

258 TABULATE CORALS.

When we consider the structural characters of Heteropora,
as above briefly indicated, it cannot be denied that there is a
general resemblance between this type and the ancient Monti-
cuiipora and FistiUipora. Dr Lindstrom, in the memoir already
referred to, has further brought forward a considerable body of
evidence, which I shall more fully allude to hereafter, to prove
that the developmental history of Montiailipora shows it to be
a Polyzoon. In the meanwhile, however, I am unable to admit
that we have sufficient evidence for the removal of Montiaili-
pora and its allies from the Actinozoa, and their transference
to the Polyzoa. So far as Hdcropora is concerned, the genus
seems to be sufficiently separated from Montictdipoi'a by its
total absence of genuine tabulae in the cells themselves and its
(occasionally) perforated walls, together with the occurrence in
some forms of radiating septa in the interstitial tubes. On
the other hand, Moiiticidipora presents the closest possible
resemblance in most of its structural features to the ramose
Favositidce', from which it can only be separated by the general
possession of two sets of corallites and the apparent absence
of mural pores. That the latter are true Actinozoa does not,
in my opinion, admit of doubt, and I think we must in the
meanwhile come to the same conclusion as reo^ards Monticuli-
pora itself and the closely-allied Fistulipora, Consieiiaria, and
Prasopora. The three last of these types, and the great
majority of the forms usually included under the first name,
possess a corallum which is composed of two distinct sets of
corallites, a feature which at once reminds us of the Helio-
poridcB, and would lead us to suppose that the MoiiticuliporidcE
are to be regarded as an ancient group of Alcyonaria. More-
over, the different sets of corallites in these forms are not only
unlike in point of size, but the smaller tubes are almost in-
variably more closely tabulate than the larger tubes, this being
another feature in which they unmistakably approach the
HelioporidcE. In no known forms of Polyzoa^ not even in
Heteropora, can a similar condition of parts be shown to exist,
and I am therefore of opinion that we are not justified, with

CH^TETID^ AND MONTICULlPORIDyE. 259

the evidence now before us, in removing the MonticnliporidcB
from the Actinozoa, and that we may provisionally regard them
as a special group of Alcyonaria. It should also be borne
in mind In this connection that we are at present quite un-
acquainted with the animal of Heteropora, and that it is just
possible that an examination of the soft parts of this type
— admittedly a very aberrant form of the Polyzoa — might
show it to be a Coelenterate. At the same time, I do not at all
mean to deny but that some of the fossils which have been
described by various palaeontologists under the names of Mon-
ticulipora, Fistulipora, or Callopora, are probably really Polyzoa,
Erroneous determinations of this kind, especially where micro-
scopic examination has not been resorted to, are almost inevit-
able ; but they do not affect the systematic position of the
forms which are recognised as the types of Monticulipora and
of the genera related to this.

26o

CHAPTER XIII.

GENERA OF CH.ETETID.E AND MONTICULIPORID^.

CH^TETID.^.

Gcmis CiL-ETETES, Fischcr, 1837.,
(Oryct. de Gouv. de Moscou, p. 159.)

Gcii. Char. — Corallum massive, composed of long irregu-
larly prismatic erect corallites, which are closely contiguous, and
are completely amalgamated by means of their walls. Coral-
lites of one kind only, opening upon the surface by means of
irregularly polygonal, non-oblique calices, and destitute of true
septa. Walls imperforate. Tabulae complete, comparatively
remote, often placed at corresponding levels in contiguous
tubes. Visceral chamber often partially divided by an imper-
fect longitudinal septum (or by two such septa) resulting from
the uncompleted fission of the tube into two young corallites.

Obs. — It is not necessary to enter here into a detailed ac-
count of the genus Chcetetes, except in so far as concerns its
relations with the genera Stciiopora, Lonsd., 2,Vi.^ Montiatlipora,
D'Orb., and even on this point little need be said. The type
of the genus CJicutctcs is unquestionably the great C. radians,
Fischer, of the Carboniferous Limestone of Russia, and the
characters of the genus must, therefore, necessarily be based
upon this species. This form was for the first time adequately

GENERA OE CH.ETETID.E AND MONTI CULlFORIDAi. 261

described by Mr Lonsdale (Geol. of Riiss., vol. i. p. 595, 1845),
who drew special attention to the fact that the walls of the
corallites are inseparably united, so that fractures expose the
iiitcrioj' of the tubes, this structure depending upon the fissi-
parous mode of increase of the coral. M'Coy (Brit. Pal. Foss.,
p. 82, 185 1) may be considered as entirely accepting Mr Lons-
dale's views as to the characters of the genus Chcetctcs. Milne-
Edwards and Haime (Brit. Foss. Cor. Intr., p. 61, 1850), while
accepting the genus, ignore the feature just alluded to as so
strongly emphasised by Mr Lonsdale, and add no character
which could be accepted as in any way of generic value. In
the " Polypiers Fossiles" (p. 261, 185 1) the same authors give
a fuller account of Chcstetes, and they now unite with it the
genus Steiiopora, Lonsd., and also the ill-characterised type
which D'Orbigny had named Monticulipo7''a (Prodr. de Paleont. ,
t. i. p. 25, 1850). At a still later period (Brit. Foss. Cor., p.
264, 1854), the two distinguished French observers so far
altered their views that they accepted Monticulipora, D'Orb.,
as distinct from Cha^tdcs, Fischer, the ground of distinction
being that in the former the corallum increases by gemmation,
whereas in the latter the mode of growth is by fission. Most
subsequent writers have followed the course ultimately adopted
by Milne-Edwards and Haime, so far as concerns the generic
distinctness of Chcetetes and Monticidipoi-a, and the grounds
of this distinction. In a paper, however, upon the species of
Chcetetes in the Lower Silurian rocks of North America
(Quart. Journ. Geol. Soc, vol. xxx. p. 499, 1874), I formerly
expressed the opinion that the genera Chcrtctes and Monticuli-
pora were not sufficiently differentiated, and that the mere
mode of growth, even if admitted to be of generic value, was a
character so difficult, in many instances, of determination, that
it should not be regarded as of itself sufficient to separate two
types otherwise closely allied. At the same time I stated that
I thought Stetwp07^a^ Lonsdale, to be insufficiently character-
ised, and pointed out that different observers had defined this
genus by means of very different and in some cases compara-

262 TABULATE CORALS.

tively trivial features. To the opinions expressed in the paper
just referred to I still adhere — in the sense, that is, that I still
think the conclusion which I had then reached the only one
justified by the information at that time published. Since that
time, however, I have had the opportunity of making a careful
microscopic examination of authentic Russian specimens of C.
radians, Fischer, the type of its genus, and I am now quite
satisfied as to its generic distinctness ; while a similarly minute
investigation of Montictilipora and its allies has convinced me
that here also we have to deal with a distinct generic type.
Lastly, as has been previously shown, I have had now the op-
portunity, in association with my friend Mr R. Etheridge, jun.,
of examining authentic Australian specimens of Stenopora,
Lonsd., and have thus been able to show that this genus is one
quite distinct from either Chcstetes or Monticulipora, and, in
reality, referable to the Perforate group of the Favositidcs.

The type, then, of the genus ChcBtetes, as here restricted, is
the C. radians, Fischer, of the Carboniferous of Russia, and the
generic diagnosis previously given is founded upon an exami-
nation of the structural characters of this form. It has, how-
ever, been pointed out by Mr R. Etheridge, jun., and myself
(Journ. Linn. Soc, vol. xiii. p. 365, 1877) that the corals known
as Alveolites septosa, Flem., and A. depressa, Flem., are generi-
cally inseparable from ChcBtetes radians, Fischer ; and we have
further described another species {Chcetetes hypcrboretLs), from
the Carboniferous rocks of Scotland, as possessing similar
generic characters. All the forms just mentioned are of Car-
boniferous age, and there are no published species of corals from
either older or younger deposits which can, in the meanwhile,
be certainly asserted to belong to the same genus. I may say,
however, that I have collected in the Devonian Limestone of
Gerolstein, in the Eifel, specimens of a coral which would ap-
pear to be congeneric with C. radians, Fischer.

If we take the corals just mentioned as the only satisfactorily
identified species of Chcstetes, we find that the corallum is mas-
sive and usually irregularly hemispherical or pyriform in shape,

GENERA OF CH.ETETID.E AND MONTICUIJPORID.E. 263

rarely (C hyperboreus, Nich. and Eth., jun.) forming thin flat-
tened expansions, with a concentrically-striated epitheca below.
The corallites are irregularly polygonal, and are in complete
contact throughout their entire length. Rough fractures (gen-
erally, but not always) expose the interior of the tubes ; and
thin sections, whether transverse or longitudinal (PI. XII., figs.
4, 4 a, 4. d), show that the walls of contiguous corallites are
entirely and undistinguishably amalgamated or fused with one
another, the originally duplex character of the partition between
neighbouring corallites being in no case recognisable. Though
somewhat variable in shape and size, the corallites are indubi-
tably of one kind only, and there is no reason for believing that
the corallum consisted of two distinct sets of zooids. The
corallites, further, are not reclined, as in the typical species of
Alveolites, Lam., but are erect, in precisely the sense that this
term is employed in speaking of the massive coralla of species
oi Favo sites, such as F. Gothlandica, Lam., and its allies. The
calices, therefore, though wanting the regularly polygonal form
of those of Favosites, are never oblique or semilunar, with one
lip more prominent than the other, as is so characteristically
the case in Alveolites and its allies. The walls of the corallites
seem to be wholly imperforate, and as this conclusion is based
upon a minute examination of thin sections as well as of actual
specimens, its correctness may be accepted as tolerably certain.
This character, therefore, alone is sufficient to separate Chcetetes
from all the externally similar genera of the Favositidce. No
traces whatever either of lamellar or of spiniform septa can be
detected in thin sections or in the specimens themselves (except
some obscure longitudinal striae in C. scptostts\ and these struc-
tures must therefore be considered as wholly wanting. There
exists, however, in a certain number of the corallites a curious in-
ward projection of the wall (PI. XII., figs. 4, 4(5), which is seen
both in typical specimens of C. radians, Fischer, and also in C.
hype7^boreus, Nich. and Eth., jun., C. {Alveolites) scptosns, Flem.,
and C. {Alveolites) dcpressus, Flem. In the two last-mentioned
species this inward process was noticed and figured by Edwards

2 64 TABULATE CORALS.

and Haime, and they regarded it as being a " septal tooth,"
similar to the unpaired septal ridge of certain species of Alveo-
lites, As pointed out by Mr R. Etheridge, jun., and myself,
however (Journ. Linn. Soc, vol. xiii. p. 366), this supposed
septal tooth was more correctly interpreted by Mr Lonsdale
(Geol. Russ. and Ural, vol. i. p. 95), who regarded it as being
an inflection of the wall of the corallite, due to its undergoing
the process of division by fission into two tubes. That this
view is the correct one is shown by the fact that this inwardly-
projecting ridge is of variable length and of equally variable
occurrence. It is never present in more than a quite limited
number of the tubes, and it varies in size from a hardly per-
ceptible protuberance up to a vertical lamina extending half-
way or more across the tube, while it is not uncommonly faced
by a corresponding ridge upon the opposite side of the vis-
ceral chamber. Lastly, the tabnhe in Chcstetes are always well
developed, and are invariably complete and horizontal. Mr
Lonsdale considered that the tabular of Chcstetes were placed
at corresponding and remote levels, and separated by zones
in which no tabulae were developed, but Milne-Edwards and
Haime explicitly deny this (Pol. Foss. des Terr. Pal., p. 261).
So far as Cluetetes radians, Fischer, is concerned, the truth
seems to lie between these two extremes, for the tabulee are
certainly developed throughout the entire course of the coral-
lites at comparatively remote intervals (PI. XIL, fig. 4 d)\ but
they are, at the same time, periodically developed at corre-
sponding levels at certain horizons, so that the corallum as a
whole readily splits into a series of concentric layers. \\\ the
other species here included in the genus the tabulae appear to
be developed more irregularly, though they are always present.
As regards the zoological affinities of Chatetcs, it is not pos-
sible at present to reach any final conclusion. In spite of the
resemblance of the corallum of Chert etes to that of some forms
ol Favosites (such as F. Bozverbanki, E. and H., sp.), it is quite
clear that there is no direct relationship between these two
types, if we admit that the former possesses imperforate walls,

GENERA OF CH.ETETIDAi AND MONTICULIPORID.E. 265

as seems all but absolutely certain. At the same time, I see
no reason whatever for accepting the view, advocated at the
present day by high authorities, that Chcetetcs is not truly a
Coelenterate. I am quite unable to recognise in the structure
of the fossils referred to this genus anything which would
justify us in referring them to the Polyzoa (as advocated by
Lindstrom and others), and I think the general details of their
structure to be such as are only compatible with their being-
members of the Coelenterata. The precise position which they
should occupy among the Actinozoa is a point upon which it
is far more difficult to arrive at any positive conviction. Upon
this point, while confessing the absence of positive evidence, I
can only say that I am disposed to agree with Professor Martin
Duncan (Third Rep. on Brit. Foss. Cor. ; Brit. Ass. Reports,
1 87 1, p. 128) in thinking that Cho'tctes is probably an Alcy-
onarian.

As to the relations of Chcetctes to allied genera, it can only
be said at present that there is nothing save close external
resemblance to unite the genus with any other, and especially
with the group of which Monticttlipora is the central type.
For reasons previously given, I have not thought myself
justified in definitely separating the species of the latter from
Chcetctes, with which they often agree in general form and habit,
as well as in the imperforate walls of their corallites ; but I
entertain at the same time a strong conviction that there
is little or no true affinity between the two. Most of the
so-called Moiitiailiporce, apart from other peculiarities, have
heteromorphic coralla, composed of two distinct sets of
zooids, and in all of them the walls of the corallites are
not amalgamated with one another. These distinctions alone
are quite sufficient to fundamentally separate the typical forms
of Monticulipoi^a from Chcstetes. The type with which Chcetdes
shows the strongest affinity is the Silurian Tetradiumi but in
this genus we have well -developed and definitely- disposed
lamellar septa, and we can therefore hardly suppose that
the two genera are closely related.

266 TABULATE CORALS.

The species of Chcetetes, as here defined, are not known to
occur out of the Carboniferous (and possibly the Devonian)
rocks ; and I shall give a brief description of the type-
species, C. radians, Fischer, founded upon an examination
of specimens derived from the Carboniferous Limestone of
Russia and the north of England.

Chsetetes radians, Fischer.

(PI. XII., figs. 4, 4 ^.)

Chceteies radians, Fischer, Oryct. de Moscou, p. i6o, PI. XXXVI., fig. 3, 1830.
„ radians, Lonsdale, Russ. and Ural, vol. i. p. 595, PI. a, fig. 9, 1845.
„ radians, Milne-Edwards and Haime, Pol. Foss. des Terr. Pal., p. 263,

PI. XX., figs. 4, 4 a, 185 1.
,, radiajis, Milne-Edwards and Haime, Brit. Foss. Cor., p. 158, 1852.

Spec, Char. — Corallum massive, of large size, composed of
long basaltiform, closely contiguous corallites, which are inti-
mately united by their walls. Calices irregularly polygonal,
often elongated, being in the former case about a fourth of a
line in diameter on an average, whereas in the latter case they
are about one-fifth of a line or less in their short diameter, and
one-third of a line in their long diameter. Walls imperforate.
Septa wanting. Visceral chamber commonly partially divided
by an imperfect longitudinal partition on one side, which ap-
pears in the calice as a tooth-like process, and which is some-
times confronted by a similar process proceeding from the
opposite wall of the tube. The tabulae are complete, well
developed, variable in number, sometimes about a quarter of
a line apart, sometimes much more remote, and often specially
developed along planes concentric with the surface, so that the
corallum splits into a succession of concentric layers or zones.

Obs. — The Russian examples of this species which I have
had the opportunity of examining form large masses of a
pyriform shape, six inches or more in height, and composed
of long basaltiform tubes which are in complete contact

GENERA OF CH.ETETIDM AND AlONTICULIPORID^. 267

throughout, and which, though somewhat unequal in point
of size, are not divisible into a series of larger and smaller
corallites. Transverse and longitudinal microscopic sections
(PI. XII., figs. 4 and 4 a) show that the walls of contiguous
corallites are absolutely and uniformly amalgamated, so that
no traces whatever can be detected of the original divisional
lines between them. The walls are thick, and the most care-
ful examination both of actual specimens and of thin sections
has failed to produce any evidence of the existence of mural
pores ; so that we must accept the view held by all the older
observers of this species as to the imperforate condition of the
walls of the corallites. The calices, like the corallites, are un-
equal in point of size, though in no uniform manner, and com-
monly exhibit an inward tooth-like projection (PI. XII., fig. 4 b)
on one side, sometimes with a similar but smaller correspond-
ing process on the opposite side of the tube. These tooth-
like projections are never present in more than a quite limited
number of the tubes, and they vary much in length ; while
transverse sections (PL XII,, fig. 4) show them to be pro-
duced by the existence of a vertical lamella or longitudinal
inflection of the wall of the corallite. Their true nature was
pointed out by Lonsdale {Joe. cit.), who maintained that they
were due to the uncompleted fission of the old tubes, the fissi-
parous mode of development being characteristic of the species.
The correctness of the views of Mr Lonsdale upon this point
has subsequently been upheld by Mr R. Etheridge, jun., and
myself (Journ. Linn. Soc, vol. xiii. p. 366). The tabulae
(PI. XII., fig. 4 a) are always numerous, and are invariably
complete and horizontal ; and Milne-Edwards and Haime are
perfectly right in asserting (in their description of the genus
ChcBtetes) that they are not uniformly placed at corresponding
levels in contiguous tubes. At the same time Mr Lonsdale is
correct in his assertion that the species possesses " diaphragms
in parallel bands ; " for the tabulae are specially developed peri-
odically, at the same level in all the tubes, so that the corallum
is conspicuously composed of a succession of concentrically dis-

2 68 TABULATE CORALS.

posed strata, which generally have a thickness of from half an
inch to three-quarters of an inch.

In addition to specimens from the Carboniferous Limestone
of Moscow, I have examined a number of examples which I
have collected from the Carboniferous Limestone of the north
of England — a formation from which C. radians is quoted by
Milne-Edwards and Haime. The British specimens entirely
resemble the Russian ones in their shape and general configu-
ration, in their long basaltiform corallites, and in the composi-
tion of the corallum out of concentrically disposed strata formed
by a periodic development of tabulae at corresponding levels.
At the same time there are some differences between the two
sets of specimens. The English examples (PI. XII., figs. 4 c
and 4 d) have rather smaller tubes, which are more regularly
polygonal, and more uniform in shape, and which are slightly
more thin-walled than is the case in Russian specimens. The
tabulae also are not nearly so numerous, and few of these struc-
tures are developed between the concentric zones of these
diaphragms, by which the whole colony is divided into super-
imposed strata. At the same time, there is the same total
amalgamation of the walls of the corallites, and in certain of
the tubes we always see the same tooth-like projection indicat-
ing the approaching division of the corallite into two. Upon
the whole, therefore, in spite of the differences just noted, I am
not disposed to regard the British specimens as more than a
mere variety of the typical C. radians of Russia.

As has been already pointed out, C. I'adians, Fischer, is
closely allied to C. {Alveolites) septosiis, Flem., C. {Alveolites)
depressus, Flem., and C. hyperboreiis, Nich. and Eth., jun., with
which it forms a most natural group ; and all of these forms
are characteristic of the Carboniferous Limestone. The last
mentioned of these species is easily separated from C. radians
by the lamellar and expanded form of the corallum, as well as
by other characters, and C. dcprcssiis, Flem., is similarly separ-
able by the very small size of its tubes. On the other hand,
C. {Alveolites) scptostis, Flem., so nearly approaches C. radians

GENERA OF CH.ETETID.E AND MONTI CULIPORID.E. 269

in its leading characters, that the specific distinctness of the
two may well be called in question, but I am unable to offer
any definite opinion upon this subject till I may have been able
to examine the original specimens of the former species. All
that I can say now is, that such specimens as I have seen of
the British Carboniferous coral ordinarily called by the name
of C. scpfos2is, or Alveolites septosa, seem to be very similar in
appearance and structure to C. radians, Fischer, though a
microscopic examination may yet show that they are distinct.

Fomnatiou and Locality. — Carboniferous Limestone of Mos-
cow, Russia. Not uncommon in the Carboniferous Limestone
(" Orton Scar Limestone ") of Hardendale Nab, near Shap,
Westmorland, and in the same limestone at Penruddock,
Cumberland. (Quoted by Milne-Edward and Haime from the
same horizon at Kendal, Westmorland.)

MONTICULIPORID.-E.

Genus Monticulipora, D'Orbigny, 1850.

(Prodr. de Pale'ont., t. i. p. 25.)

Nebjilipora, M'Coy, Ann. Nat. Hist., ser. 2, vol. vi. p. 282, 1850.
Orhitiditcs, Eichwald, Zool. Spec, t. i. p. 180, 1829.
Orbipora, Eichwald, Leth. Rossica, t. i. p. 484, i860.
Stenopora, M'Coy ? (non Lonsdale), Brit. Pal. Foss., p. 24, 1851.

Gen. Char. — Corallum very variable in shape, massive,
ramose, laminar, frondescent, or encrusting, composed of nu-
merous tubular closely-approximated corallites, the walls of
which are not amalgamated with one another. Walls imper-
forate (so far as certainly known, though one or two forms
otherwise undistinguishable from the genus unquestionably
possess " mural pores"). Septa entirely wanting. Tabulae
always well developed, complete. Corallites usually distinctly
divisible into two series, one of large and the other of small
tubes, the latter usually more closely tabulate than the larger
ones, or otherwise differing from these in structure. Surface

2 70 TABULATE CORALS.

commonly exhibiting at regular intervals definite areas occu-
pied by corallites which are larger or smaller than the average.
These areas are commonly elevated above the general surface,
and are then known as " monticules,"

Obs. — The corals which are usually known by the name of
Montinilipora, together with the forms allied to this, constitute
perhaps the most intricate and difficult assemblage of Palaeozoic
fossils with which the zoophytologist is called upon to deal. I
had originally intended to devote considerable space to this
group ; but I find that the limits of this work will not allow of
my carrying out this intention, and I have decided rather to
publish an entirely separate memoir upon the MoiiticidiporidcE.
Here, therefore, I shall merely give a brief outline of the
general results of the investigations which I have been carrying
out as to the internal structure of the corals usually referred to
Monticiilipoi^a and allied types.

[It may not be out of place if I add a iQ\v remarks here as to the proper
method of making thin sections of the MonticidiporidcB ; for the results which I
have obtained will certainly not be reached by other investigators, unless they
follow the plan of procedure which I have 'adopted. In any massive or ramose
Monticidipora (and, I may add, in any coral similarly composed of tubular
corallites radiating from an imaginary axis), the true structure can only be under-
stood by making three distinct sections. Two of these sections are perfectly
obvious and natural ones — one being transvejse, or at right angles to the long-
axis of the corallum, while the other is vertical, and is taken iti the median plane
of the corallum and parallel ivith its long axis. I used myself to consider these
two sections sufficient, and probably others have entertained a similar opinion.
Owing, however, to the fact that the diverging corallites often very materially
alter their character just before they open on the surface, and owing also to the
generally very limited inward extension of the interstitial small corallites (the
so-called " coenenchymal tubules"), as also of the curious intertubular spines
which are commonly present, it is absolutely necessary to make a third series
of sections which should run Just below the calices of the corallites and at right
angles to the long axis of the latter. The direction in which it will be necessary
to cut any given coral to obtain sections of this nature will always vary with
the form of the corallum ; but these sections may be termed tangential, as they
must in all cases be taken in a direction tangential to the calicular surface and
just below that surface. Sections of this kind are most instructive and im-
portant; and from my ignorance of their value and consequent neglect to pre-
pare them, I have fallen into grave errors, or failed to seize the true structure,
in the case of certain forms of this group, of which I have on former occasions
described the minute characters.]

GENERA OF CH.ETETIDyE AND MONTICULirORIDyE. 271

The genus Monticulipora was founded by D'Orbigny in
1850 (Prodr. de Pal., t. i. p. 25, where the date of the genus is
given as 1847); the only definition being: "cellules serrees,
poriformes a la surface, d'un ensemble rameux ou encroutant
couvert de petites saillies coniques." The first species given
under this definition is the well-known M. mamimdata,
D'Orbigny, of the Lower Silurian of the United States, which
must, therefore, be accepted as the type of the group. It will
be quite obvious that the only character in the above definition
which has the very remotest generic value, is the existence of
conical elevations or " monticules " upon the surface, and even
the nature of these elevations is left wholly undefined. The
genus Nebulipoi'a, M'Coy (Ann. Nat. Hist., ser. 2, vol. vi.
p. 282, Oct. 1850) was founded in the same year as Monticuli-
p07^a, and includes forms unquestionably congeneric with the
latter, though I am unable from his figures and descriptions to
be sure as to the precise species upon which M'Coy founded
his genus. This point, indeed, could only be set at rest by an
examination of the original specimens in the Woodwardian
Museum, which I have unfortunately had no opportunity of
inspecting. It is, however, a matter which, I think, will still
admit of discussion, as to whether or not M 'Coy's Nebtilipoi'a
should not be adopted as the title for the fossils now under
consideration, rather than the Moiiticitlipora of D'Orbigny. I
am not able to decide this point, and I will only remark, further,
that M'Coy, in his generic diagnosis, states that the walls of
Nebulipora are " apparently perforated by rows of small fora-
mina," though he does not allude to this character again, and
seems to have been doubtful as to its actual existence. The
typical Montictiliporce seem to be undoubtedly devoid of mural
pores ; but I have examined (through the kindness of my
friend Mr R. Etheridge, jun.) a specimen from the Wenlock
Limestone of Dudley in the collection of the British Museum,
which has all the external and general characters of such 2^Mon-
ticidipora as M. petropolitana, Pand., but in which the walls of
the corallites are unquestionably minutely porous. It is not

2 72 TABULATE CORALS.

impossible, therefore, that it is upon some such specimen as
the preceding that M'Coy founded the statement that I have
referred to.

As regards the later history of Monticiilipora, it is sufficient
to add here that Milne-Edwards and Haime at first placed all
the forms referred to this genus under Cho'tctcs (Pol. Foss. des
Terr. Pal, p. 261, 185 1), but that they subsequently accepted
the genus as distinct (Brit. Foss. Cor., p. 264, 1854). In this
course — whatever differences of opinion as to the affinities of
the genus may have been expressed — Milne-Edwards and
Haime have been followed by almost all paleeontologists. For
my own part, as previously mentioned in speaking of Chcetetcs,
I have been disposed to consider that no sufficient characters
had been indicated whereby Monticidipora, D'Orb., could be
separated generically from ChcEtdes, Fischer ; and I have de-
scribed a number of species of the former genus under the
latter title. Having now, however, had the opportunity of
examining authentic specimens of the type-species of Chcetetcs
(the C. 7'adiaiis, Fischer, of Russia), I am quite satisfied as to
the complete distinctness of this genus, and, consequently, as
to the necessity for retaining the genus Montictdipora.

The genus Monticulipora — using this term in the meanwhile
in a wide general sense — includes Palaeozoic coralla of the most
variable form. In many cases the corallum is massive, con-
sisting of a variably-shaped aggregation of diverging corallites
based upon an inferior epitheca, and having the calices placed
exclusively upon the upper surface. In other cases, including,
perhaps, the majority of species, the corallum is ramose, or
dendroid, fixed by its base, and having the calices opening over
the whole of the free surface. In another group the corallum
is fixed by its base, but has the form of a flattened, palmate,
and variously-divided frond, the corallites diverging from the
imaginary median plane of the expansion and opening on the
two flat surfaces. In still another group, the corallum forms
a thin crust, growing parasitically upon foreign bodies ; but
though some undoubted species of the genus have this habit, it

GENERA OF CH.ETEriDyE AND MONTICULIPORID.E. 273

is probable that a considerable number of the so-called en-
crusting Alonticidiporce will prove, upon adequate examination,
to be truly of a Polyzoan nature. Be this as it may, it is quite
certain that the mere form of the corallum, though affording a
useful guide to the collector, is usually of no value whatever in
determining the structure and affinities of a given specimen of
Monticulipora. As an illustration of this fact, I may mention
that among- the corals which, from their general form and
superficial characters, would unhesitatingly be placed under the
well-known species M. petropolitana, Pand., I find at least
three well-marked types to be included, which differ so widely
from one another in minute structure, that they might well be
regarded as at least distinct sub-genera. At the same time,
certain species, and especially those which have a laminar or
frondescent corallum, are very constant in their mode of
growth, so that in these cases the form of the corallum really is
of value in the determination of species ; while the ramose
species, however variable, never appear to form crusts on
foreign bodies, as some of the massive species occasionally do.
The corallites in MonticiUipora may be distinctly prismatic or
polygonal, or they may be rounded and nearly cylindrical, but
in either case they are always in close contact, and they never
really exhibit the condition of parts characteristic of C/icetetes
proper, in which, as has been shown, the walls of contiguous
corallites are so completely amalgamated that the original lines
of demarcation between neighbouring tubes cannot be in any
way detected. In some cases {e.g., in the typical M. petropoli-
tana, Pand.) the walls are so thin that the partitions between
the visceral chambers of contiguous corallites appear to be
absolutely indivisible, and present themselves in thin sections
merely as delicate dark lines (fig. 35, a). This is, however, a
state of parts very different to what occurs in Chcstetes proper
(fig. 35, d), and is much more nearly comparable to what we
observe in many species of Favosites. In other cases, the
condition of things is very like that observable in Favosites
generally, in which the walls of contiguous tubes are distinct,

s

274

TABULATE CORALS.

and the line of demarcation between them remains clearly
marked out in cross-sections of the corallites (fig. 35, c). This
occurs, for example, in typical specimens of M. pulckelia, E.

F'S- 35- — A, Tangential section of a few corallites of the typical Alonticidipora pdropolitana,
Pand., from the Lower Silurian of Sweden; B, Tangential section of a corallite of a typi-
cal example oi Alontiadipora rainosa, E. and H., from the Cincinnati group of Ohio ; c,
Tangential section of a corallite oi Moiiticiilipora pulchella, E. and H., a typical example
from the Wenlock Limestone of Dudley; D, Tangential section of a corallite of the ty])i-
cal Chatetes radians, Pand,, of the Carboniferous rocks of Russia. All the sections are
taken just below the calices ; a, b, and c are enlarged fifty times ; D enlarged twenty-
five times.

and H., from the Wenlock Limestone of England. In still
another group of cases, embracing many typical species of the
genus {e.g., M. mammtdata, D'Orb.), there is no dark line
running in the centre of the partition between contiguous tubes,
and the walls thus at first sight appear to be amalgamated, as
they actually are in Chcstetes proper. In these cases, however
(fig. 35, b), the state of matters really differs widely from that
which exists in Chcstetes proper, since each visceral chamber is
enclosed by a distinct dark line, usually circular or oval in out-
line, marking the original boundary of the tube, and the inter-
spaces between these dark lines are filled in by sclerenchyma of

GENERA OF CH^TETID^ AND MONTICULIPORIDyE. 275

a different texture and much lighter colour. In these cases,
therefore, it would appear that the corallites are not only primi-
tively distinct, but that in approaching the surface they do not
touch each other at all to begin with, or only to a very limited
extent, the ultimate union of the corallites being effected by
means of a secondary deposit of calcareous matter. In such
forms as these, therefore, the corallites in the deeper parts of
the corallum are thin-walled, closely contiguous, and more or
less polygonal ; whereas they become much thickened and
more conspicuously circular or oval in shape as their mouths
are approached. The structure of the wall is, in fact, very
similar in these cases to what is observable in Stenopoi'u,
Lonsd,, except that the thickening of the tubes is uniform, and
is not confined to the production of periodic rings.

Apart from the evidence of microscopic sections, into which
I cannot fully enter here, the permanent non-amalgamation of
the walls of the corallites in Monticidipoi'a is shown by the fact
that fractured surfaces invariably exhibit the exterior of the
tubes. This was long ago noticed by Lonsdale, and was set
down by him to the fact that the corallum of Moiiticulipora
increased by gemmation, whereas that of Chcetetes produced
new tubes by a process of fission. In the latter, therefore,
rough fractures exhibit the interior of the corallites. Of the
correctness of Lonsdale's observations on this point — as obser-
vations— I can entertain no doubt ; but I am not clear that the
phenomena are really due to the cause which he assigns. That
Chcetetes increases fissiparously is certain ; but I am not sure
that gemmation is the regular or exclusive mode of growth
amongst the MonticuliporcE. I have formerly expressed the
opinion (Ann. Nat. Hist, ser. 4, vol. xviii. p. 86) that certain
species of Monticidipora exhibited fissiparous growth ; and
though further observations have shown me that I relied upon
evidence which admitted of misconstruction, and that gem-
mation is the common mode of increase in the Monticuliporce,
I am still inclined to think that the phenomena manifested by
thin sections show that fission of the old tubes occurs at times

2 76 TABULATE CORALS.

as well. At any rate, I feel sure that the difficulty of deter-
mining this point in the case of the smaller species is so great
that I am right in the formerly expressed opinion that this
character alone should not be accepted as an adequate generic
distinction between Chcetetes and Alonticulipora (Quart. Journ.
Geol. Soc, vol. XXX. p. 500).

There is at present no evidence as to the existence of
" mural pores " in Monticiilipora or its allies. Considering the
minute size of the tubes, and the great difficulties which com-
monly attend the detection of these apertures in microscopic
sections, the non-recognition of pores does not absolutely imply
their non-existence. We know that pores are present in the
similar-looking Stenopora, Lonsd.; I have previously shown that
similar apertures exist in the Favosites Bowerbanki, E. and H.
sp. of the Upper Silurian, which has hitherto been regarded as
a Monticulipora ; and, as before remarked, I have recently
examined a specimen from the Upper Silurian of Dudley, in
which the general characters of Moniiciclipora are present, but
the walls are minutely porous. Moreover, the microscopic ex-
amination of weathered or fractured surfaces often brings to
light deficiencies in the walls of the tubes, though whether these
are accidental, or are really of the nature of " mural pores," is a
point upon which I have hitherto been unable to satisfy myself.
In the want of direct and positive evidence, we must at present
assume the walls in Alonticttlipora and its allies to be imper-
forate. At the same time I should not be surprised if future
and more extended investigations should show that mural pores
really exist ; though it may be safely assumed that any struc-
tures of this kind that may be detected will prove to be pro-
portionately more minute, and more irregular in their size and
distribution, than is the case with these openings in the typical
Favositidcs.

Whatever may be the condition of the walls in Montiatlipora,
microscopic examination brings out very clearly the important
fact that in the vast majority of cases, and probably invariably,
the corallum is truly dimorphic, and consists of two different

GENERA OF CH.ETETIDyE AND MONTICULIPORID^. 277

sets of corallites, which must, during life, have been inhabited
by different sets of zooids. The existence of minute tubes,
either scattered among the larger ones, or aggregated in
special groups, has, of course, been long known to palaeontolo-
gists ; but these have, for the most part, been regarded either
as merely young corallites or as " coenenchymal tubuli."
Similarly, palaeontologists have long known that certain species
oi Monticulipora {e.g., M. pttlckella, E. and H.) exhibit groups
of large tubes distributed at intervals among those of average
size ; but the true import of these appearances hardly admitted
of recognition save by the light of Mr Moseley's researches
upon the living Heliopora. I have, however, now thoroughly
satisfied myself that the corallum in Alontictilipora is truly
dimorphic, quite as genuinely as in Heliopora or Hcliolites.
One set of corallites may be much reduced in number, or may
undergo much modification, but I believe that the existence of
two different kinds of tubes can almost always be demon-
strated ; and the importance of this fact, from a theoretical
point of view, can hardly be over-estimated. The relations of
the two sets of tubes to one another vary extremely in different
forms of Monticulipora, and I shall employ these variations as
the basis of a provisional classification of the multitudinous
forms included under this head. I shall, therefore, postpone a
further consideration of this subject till I come to speak of the
different groups which may be comprehended under the general
name of Monticulipora.

I must, however, briefly notice here certain peculiar super-
ficial features In different species of Monticulipora, which are
in reality due to the dimorphic condition of the corallum just
spoken of. The appearances presented by the calices vary
according as we have to deal with a form in which the walls of
the corallites remain permanently more or less thin throughout
their entire extent, or with one In which the tubes undergo a
marked thickening before reaching the surface. In the former
of these cases the calices are polygonal and sharp-edged, and
thus resemble the calices in a Favosites of the normal type. In

2 78 TABULATE CORALS.

the second case, the caHces are rounded, oval, or subpolygonal,
and exhibit thick and rounded margins — reminding us, so far
as this particular character goes, of the calices of a Pachypora
or a Stenopora. Monticulipora petropolitana, Pand., and its
allies may be taken as exemplifying the former condition ;
while J/, ramosa, D'Orb., AT. luammtilata, D'Orb., M. frondosa,
D'Orb., M. Janiesi, Nich., M. ttmiida, Phill., and many others,
are examples of the latter state of parts. Those forms, more-
over, in which the walls are thickened towards the surface are
particularly liable to exhibit a feature, sometimes seen in the
thin-walled species, and common to most or all of the species
of Stenopora, Lonsd., which demands a little consideration here,
thouQfh its true significance is still somewhat dubious. I allude
to the occurrence of peculiar blunt spine-like structures, which
are placed, in greater or less numbers, round the calices, usually
at the angles of union of the corallites. Various Monticuli-
poroid Palaeozoic corals have been noticed by various observers
to possess these calicine spines ; and Milne-Edwards and
Haime at one time (Brit. Foss. Cor. Intr., p. Ixi) regarded the
existence of these structures as diagnostic of the genus Steno-
pora as defined by them. Structures of this nature are, how-
ever, possessed by a large number of true MontictdiporcE^ and,
notably, hy M. frondosa, D'Orb., ^/. tzcmida, Phill., M. Jamesi,
Nich., M. moniliformis, Nich. (figs. 36, 37), M. gracilis, James,
and other forms. As viewed from the surface, these spines
present themselves simply as so many blunt projections, which
do not seem, so far as I have been able to observe, to be per-
forated by any apical apertures. When examined by means of
thin sections, however, these spines are found to be in no way
of the nature of mere superficial ornaments, but they extend
into the substance of the corallum, between the ordinary coral-
lites, to a depth equal to that reached by the smaller tubes of
the colony. Tangential sections taken a little below the sur-
face (fig. 37) show that these apparent spines are composed of
concentrically laminated sclerenchyma, exhibiting in their centre
a dark circular spot or a clear circular space. There cannot,

GENERA OF CH^TETID^ AND AIONTICULIPORID^. 279

therefore, be any doubt but that these structures are primitively
hollow, though their central cavities often appear to become
filled up by a secondary deposit of sclerenchyma, as growth

Fig- 36. — a, Fragment of MonticJili-
para moniliformis, Nich. , from
the Hamilton Group of Ontario,
enlarged ; h, Portion of surface of
same enlarged further ; c, Portion
of surface of M. Barrandi, Nich.,
enlarired.

-Portion of a tangential section oi Moiiti-
citlipora i?ioniiifor>?tis, Nich., taken just below
the surface, showing the intracalicine spines,
enlarged fifty times. From the Hamilton
Group of Ontario.

proceeds. In this primordial hollowness of the spines is to be
found, I believe, the real clue to their nature ; and I can hardly
doubt that instead of being merely appendages of the corallum,
they are truly of the nature of peculiarly modified zooids or coral-
lites. The correctness of this view is most readily recognised
when we come to examine thin sections of those forms which have
usually been separated from Monticulipora under the generic
title oi Dekayia, E. and H. In these cases (PI. XV., figs, i b,
I c) the supposed spines are very much reduced in number, but
they are quite exceptionally developed, and they constitute the
well-known surface-projections, which are characteristic of the
genus. These surface-projections certainly seem to be imper-
forate at their apices, but thin sections demonstrate conclusively
that they are hollow internally, and that they only differ from
the ordinary corallites In the greater thickness and density of
their walls and the apparent absence of tabulae. I do not myself
entertain any doubt as to these being a peculiar form of coral-
lites— doubtless tenanted in life by peculiar zooids — the mouths

2 So TABULATE CORALS.

of which became closed by secondary deposit as the corallum
assumed its final characters. Nor have I any doubt that the
spines of forms like M. moniliformis, Nich. (figs. 36, 37), M.
Jamesi, Nich., M. tumida, Phill., M. gracilis, James, and others,
are similarly peculiarly modified corallites, the mouths of which
become finally closed. A further evidence of this is to be
found in such species as M. frondosa, D'Orb., in which the
spines do not appear as spines upon the surface, though thin
sections exhibit appearances precisely similar to what has been
indicated as occurring in the forms alluded to above. On the
contrary, the spines remain permanently open, and appear on
the surface as minute thickened apertures between the ordinary
calices, so that they have been both recognised and figured as
a special group of corallites (Ann. and Mag. Nat. Hist., sen 4,
vol. xviii. p. 92, PI. v., fig. 1 1). Lastly, if we admit the prob-
able correctness of the views here advanced, we have a very
interesting analogy established between certain forms of Monti-
culipora and some of the species of Stenopora, Lonsd., in which
structures of a precisely similar nature occur. Thus, if we
examine a tangential section of Stenopora Tasmaniensis, Lonsd.,
taken just below the surface (fig. 38), we see that the surface-
spines are continued inwards precisely as they are in Monti-
culipora moniliformis and allied types, while they are similarly
composed of concentrically-disposed lamellae of dense scleren-
chyma. The central cavities of the spines seem, however, to
be more or less completely obliterated with age ; and the coral-
lites in the outer portion of their course (fig. 38, a) exhibit the
annular thickenings of their walls which are so characteristic of
the genus Stenopora. In spite of these differences, the resem-
blance between the spines of the Monticnliporce above alluded
to and the similar structures in certain species of Stenopora is
so striking that one can hardly resist the conviction that there
must subsist between the two a relationship of real affinity.

More conspicuous, more generally familiar, and more uni-
formly present than the spines, are those structures in the
Monti culiporce, which are known as " monticules " and " macu-

GENERA OF CH.ETETID.E AND MONTICULIPORID.E.

!8l

lae." The "monticules" or " mamelons " are circumscribed
areas on the surface of the corallum, which are, typically, ele-
vated so as to form a series of rounded, oval, or elongated

Fig. 38. — A, Vertical section of a few of the corallites of Stenopora lasinaniensis, Lonsd., in
the final portion of their course, enlarged twenty times, showing the annular thickenings
of the tubes and the remote tabulae ; B, Tangential section of the same, taken just below
the surface, similarly enlarged, showing the transversely divided spiniform corallites be-
tween the ordinary tubes. Carboniferous, Australia.

projections, but which may be nearly or quite level with the
general surface. Sometimes the " monticules " are composed
of corallites which differ in no conspicuous feature from those
which form the rest of the coral (e.g., in J/, ramosa, D'Orb.) ;
in other cases {e.g., M. piilchella, E. and H.) the corallites
which form the " monticules " are of a markedly larger size
than the average; while in still other forms [e.g., M. froiidosa,
D'Orb.) the "monticules" — in this case flat — are occupied by
corallites much more minute in their size than those which
form the bulk of the colony. The so-called " maculae " are
simply " monticules," in which the mouths of the tubes have
become closed by a calcareous membrane.

The only other point as regards the structure of the Monti-
cidipoi^cE which need specially be noticed here concerns the dis-
position of the tabulce. These structures are invariably present
in the typical Monticitliporcr, and are almost invariably " com-

2 82 TABULATE CORALS.

plete." The only exception to the latter part of this statement
with which I am acquainted is the curious M. frondosa, D'Orb.,
in which the tabulae seem to have the form of crescentic dia-
phragms, with an excentric aperture or perforation on one side.
As a rule, the tabulae are very sparsely developed in the axial
and deeper portions of the corallum, and become much more
numerous as the tubes approach the surface. As a rule, also,
the tabulae are conspicuously more numerous and more closely
set in the smaller corallites of the two sets of tubes of which the
corallum is normally composed. In a few forms, lastly, the
tabulae may become curved, so as to assume a subvesicular or
vesicular aspect ; but this is quite an exceptional feature.

With regard to " septa " in the Monticuliporce, it need only
be said that no traces of these structures have hitherto been
detected in any Monticuliporoid. Occasionally one may see
in thin transverse or tangential sections a single azygous septum
projecting for some distance into the interior of a tube, but this
seems to be really the result of fission of a coradlite, as we have
seen to be the case in Chcctetcs.

As regards the development of the AIontictiliporcB I have little
to say from actual observation, and that little will be best said
after I have given some account of the views held upon this
subject by Dr Gustav Lindstrom (Ann. Nat. Hist., sen 4, vol.
xviii. p. 5 et seq.) As I find myself in this matter unable to
accept the conclusions of the distinguished Swedish palaeon-
tologist, it is only just that I should quote his account of the
development of Monticulipoi^a at length. Upon this point he
remarks : —

"If numerous specimens of the common M. petropoliiana,
Pand., be closely scrutinised, it will be seen that its semi-globose
colony, so closely resembling a Favosites in its initial develop-
ment, has an origin that could hardly be suspected. It begins,
indeed, as a Bryozoon, as a Discoporella, as what Hall has
termed Ceramop07^a imbricata (Pal. N.Y., vol. ii. p. 169, PI. 40
E, figs. I a-\ i). There can be no doubt that this is closely
allied to the nicQnt Diseoporella (see Fr. Smitt, Ofv. Vet. Akad.

GENERA OF CH^TETID^ AND MONTICULIPORTDJE. 283

Forhand. 1866, p. 476, PI. XL, fig. 4). The basal surface of
a Monticulipora, when the epitheca is very thin, clearly shows
that it is in its first origin a Ccramopora. The smallest Ceranip-
porcB which I have hitherto seen consist of a thin circular disc
with elevated edges. From the smooth centre of the superior
surface four or five wedge-shaped zooecia radiate outwards, each
of a length of i-5th millim., their mouths being oblique, with
the inferior lip somewhat protracted. On both sides of the
mouth there is a short, pointed spine. In its interior such a
zooecium is transversely divided by some irregular tabulae. The
interstitial tubes which are so characteristic of the Discoporel-
lidcE are also distinctly seen between the zooecia of Ceramopora.
New zooecia are budded forth in quincunx from the corner of
the old zooecia, and in the periphery of the colony they become
more crowded, having the mouth oval and erected. In the
interstices is seen what might be taken for a coenenchyma ; but
this in reality is composed of nothing but smaller irregular
zooecia. When the colony has spread out laterally, there are
seen at the sides of the first smooth centrum several others
regularly distributed on the surface, from which zooecia radiate
just as if the disc were composed of an aggregation of coales-
cent initial buds. When the colony has thus gained the expanse
of an inch or more, the zooecia grow vertically upwards, and the
colony by-and-by assumes a semi-globular shape, and is con-
verted into a Monticulipora. All the zooecia are then tubular,
their mouths quite circular, and armed with a pair of very short
spines, their size varying in different cases. The larger zooecia
have around them either an empty space, or, as above stated,
a cellular tissue resembling a coenenchyma, and consisting of
smaller circular or polygonal tubes. The walls of the zooecia
are solid, without any perforations, and interiorly quite smooth
and destitute of projecting ridges or septa. The tabulae are
very irregular in the large tubes, being oblique or deeply sunk
in the wall ; in the narrower tubes they are dense and regular.
The large zooecia are clustered in groups at tolerably regular
intervals, each group of six or eight members. In Upper

284 TABULATE CORALS.

Silurian specimens they very seldom project above the surface,
and do not form the strange monticules which are so common
on the surface of the Russian Lower Silurian specimens. I
suppose that these clusters are continuations from the original
and larofer zooecia, which were budded out round the smooth
centra when the colony was in its Ceramopora stage. In some
there is seen a sort of ' reversion,' the zooecia on the surface of
the Monticulipora having again assumed the unmistakable
characters of Bryozoon, becoming oblique and radiating as
in a Ceramopora. Longitudinal sections, however, demon-
strate that there is a direct continuation from the tubes of the
AlontiaUipora into those of the Ceramopora, or that the former
aofain have changed into the latter."

Having thus described what he believes to be the mode of
development in Monticulipora petropolitana, Pand., Dr Lind-
strom proceeds to give an account of the development of a
Silurian fossil which he terms Alonticidipora ostiolaia, and which
he identifies with the Trematopora ostiolata of Hall (Pal. N.Y.,
vol. ii. p. 152, PI. XL., fig. 5), with th.Q JVebtclipora papillata of
M'Coy {M. papillata, E. and H., Brit. Foss. Cor., p. 266, PI.
LXH., fig. 4), and with Thccostegites Jie7nisphericus of Ferd.
Roemer (Sil. Faun, of Tennessee, p. 25, PI. H., figs. 3, 3 a).
This form is stated by Dr Lindstrom to commence its existence
as a Discoporella, and then to pass into what may be called the
" Fistulipora stage," each cell being now " surrounded by a
mass of small vertical, circular, or polygonal tubes having the
appearance of a ccenenchyma," and all the tubes, both large
and small, being " traversed by tabulae of the same incomplete
type as those which characterise Monticti lipoid." ^ From this
" Fistulipora stage" the colony is stated to pass next into what
Dr Lindstrom calls the " Thccostegites stage," in which the
interstitial tubes become covered with "a thin smooth calcare-
ous membrane," leaving the larger tubes open, and causing

^ I do not understand precisely what Dr Lindstrom may mean by " incomplete"
tabulce; but the tabulae of almost all the MonticidiporiX that I have examined,
except M.frottdosa, D'Orb., are just as " complete " as tliey are in the typical mem-
bers of the Favositidcc.

GENERA OF CH.ETETID.E AND MONTICULIPORID.E. 285

their mouths to assume a circular or oval shape, and to project
above the general surface. Lastly, the fossil is said to change
into a Monticulipora by the development of regular " monti-
cules," which are " arranged in quincunx, and formed at the
points where seven or eight large cells are clustered."

In the preceding I have endeavoured to give a faithful
account of the views which Dr Lindstrom has published as
to the development of the MonticuliporcE, and upon which
he, in large part, bases his view that the fossils of this genus
are really Polyzoa. Not having had the opportunity of per-
sonally examining the specimens upon which his views are
based, it would be presumption on my part were I to impugn
the accuracy of the description which he has given of the
phenomena which he has observed — the more so as his justly
deserved reputation is a guarantee that he has not arrived
at the conclusions in question without sufficient consideration.
At the same time, I regret to find myself in the meanwhile
unable to accept these conclusions ; and though I cannot
here enter into the subject at length, I may just briefly
indicate the principal reasons which lead me to dissent from
the views of such a high authority upon this and kindred
questions. In the first place, then, it is clear that the study
of the development of a fossil organism is attended with
difficulties much more serious than those which are incidental
to a similar investigation in the case of a living animal ; since
in the latter it is generally possible to trace the actual tran-
sition from one stage of growth to another. This, by the
nature of the case, is rarely — one might almost say never — pos-
sible in the case of a fossil. It is true that in the passage of
what he has termed the " Fistiilipora stage" to the " Thecoste-
gites stage," Dr Lindstrom states that he has actually seen the
same specimen exhibiting the characters of both stages in dif-
ferent parts of its skeleton. Still the passage between the two
stages just referred to is a comparatively small step to make,
and it does not aff"ect the fact that Dr Lindstrom has not
observed — so far as I am able to understand his very clear

2 86 TABULATE CORALS.

account — the actual transition between an undoubted encrnst-
ing Ceramopora and an undoubted y"r^^ and discoidal specimen
of Monticulipora petropolitana, Pand. He has examined cer-
tain specimens which show characters Hnking the one on to
the other ; but I do not understand him to assert that he has
examined specimens which in one portion show the unmistak-
able characters of Cei^ainopora, and which in another, demon-
strably older, portion exhibit the features proper to Monticuli-
pora. I cannot, however, accept any specimens except such
as exhibit as individuals the characters of two types, as being
proof that either of the types in question has been developed
out of the other. In the second place, apart from this general
argument, which may easily be pushed too far, there are very
strong grounds for regarding Ce7'-amopora as an independent
organism quite distinct from all the forms of Monticulipora.
Thus Ceramopora is most abundant in Upper Silurian and
Devonian strata, in which MonticuliporcB are comparatively
rare fossils, while the genus is very poorly represented in
Lower Silurian strata (such as the Cincinnati formation in
North America), in which MonticiUiporce are excessively abun-
dant. An additional proof of the distinctness of Ceramopora
is found in the fact that it grows to a large size, preserving
unchanged its normal and proper characters, while the general
structure and form of its tubes are markedly unlike those of
the corallites of the MoiitictdiporcE, being reclined, with oblique
and crescentic mouths, and, so far as I have observed, wholly
devoid of tabulae. (Dr Lindstrom states that tabulae exist in
Ceramopora, but I have been unable to detect these structures
in thin sections ; though I have found tabulce in some specimens
of a Montiatlipora from the Wenlock Limestone of Dudley,
which may perhaps be the M. papillata of M'Coy, and which
certainly has more of the look of a Polyzoon than is usual in
species of Monticulipora)) Moreover, the colonies of Cera-
mopora are usually (always ?) fixed, being attached parasiti-
cally by a portion or the whole of the lower surface to some
foreign body ; whereas the corallum in the discoid species of

GENERA OF CHyETETID^ AND MONTICULIPORID^. 287

MoiiticMlipora, supposed to be developed out of the former,
is usually and normally y)r^; but it is very difficult to explain
this fact if there be any genetic relationship between the
two. Thirdly, as regards matters of actual observation, I have
never been able to detect anything of the nature of a " Cera-
mopoi'a stage" in young MonticuliporcB. This is a point
which is most easily observed in young examples of the dis-
coidal species of Monticulipora, such as M. petropolitana, and
the various forms allied to this ; and I can only say that the
most minute examples of these forms which have come under
my notice differ in no respect whatever, that I can detect, ex-
cept size, as regards their external and internal characters, from
fully-grown specimens. Fourthly, if it were the case that dis-
coidal species of Monticzdipora, such as M. petropolitana, Pand,,
grew out of the thin parasitic crusts to which Hall applied the
name of Ceramopora, we ought to be able to detect the primi-
tive " Ceramoporoid " portion of the colony at the base of thin
vertical sections of colonies of the former. I have, however,
examined a large number of such sections, and I have been
unable to detect any difference in the structure of the lowest
portion of the tubes, resting directly upon the basal epitheca,
as compared with that of the fully-grown portion of the coral-
lites. Dr Lindstrom states that the basal surface of a Aloiiti-
cjtlipora, when its epitheca is very thin, " clearly shows that it
is a Ceramopora,'' but I am unable to concur in this statement.
If the specimen be undoubtedly one of Monticulipora, then I
have never seen anything in its epithecal surface which could
be compared with the structure of Ceramopora. All that can
be said, in my opinion, on this point is that we meet in the
Palaeozoic rocks with specimens of the thin discoidal epithecae
of certain fossils (the Lichenalia of Hall), which look like the
under surface of the epithecal plate of Monticulipora petro-
politana, Pand., but which might be really referable to quite
different forms, and which mostly cannot, without the prepara-
tion of thin sections, be definitely referred either to the Ccelen-
terata or the Polyzoa. Lastly, as regards the assertion that

288 TABULATE CORALS.

certain MonticuliporcB pass through a " Fistulipora stage," and
the apparent conclusion therefrom that Fistulipora, M'Coy, is
only a temporary condition of Monticitlipora, I think it may be
said that the point at issue is narrowed essentially to a ques-
tion of words ; for I hope to show that in one sense the great
majority of the MonticuliporcB are truly Fistuliporcs. That is
to say, I think it can be shown that the forms which M'Coy
included under the name Fistulipora, and which Hall has
subsequently termed Callopora^ are, at most, mere subgeneric
forms of Monticulipora. I shall show, namely, that the pos-
session of a dimorphic corallum is a common feature in all the
MonticuliporcB properly so called, and that the Fisttilip07^cu are
only peculiar in the fact that they exhibit a special develop-
ment of the smaller tubes of the corallum. If this be admitted,
it is clear that the passage of a given species of Monticulipora
through a " Fistulipora stage " is a matter of comparatively
small importance — from a theoretical point of view. At the
same time, I shall endeavour to show that the forms included
under the names of Fistulipora, M'Coy, and Callopora, Hall,
have a real existence, in so far that the characters which dis-
tinguish these types are not of a merely temporary and tran-
sient nature, but that they exist in unquestionably adult
examples.

As regards the zoological position of the Monticuliporidcp ,
there has been of late, as is well known, a strong tendency on
the part of palaeontologists to remove them from the Coelenter-
ata, and to relegate them to the Polyzoa. Some of the grounds
upon which this step has been proposed merely concern the
general resemblance in external characters between the Mon-
ticuliporoids and certain of the Polyzoa (such as Hetcropora) ;
and I have already expressed my opinion of the value of this
resemblance in speaking of the systematic position of Chcetetes,
Fischer. The only positive and direct evidence in favour of
the removal of the MonticuliporcB to the Polyzoa is to be found
in the account of the development of the former as given by
Lindstrom, and I have given the reasons which prevent me

GENERA OF CH.ETETID^ AND MONTICULIPORIDyE. 2 89

from accepting that account. Without, then, going into this
question in detail, I may simply say that I see at present no
sufficient ground for removing the Monticuliporoids to the
Polyzoa. I do not think any weight can be attached to external
appearance in a matter of this kind. Thus, we find the com-
mon Favositcs Canadensis, Billings sp., of the Devonian of
Canada, to be so entirely similar in the form and appearance
of its colonies to examples of Fistulipora, M'Coy, that it was
unhesitatingly referred to this genus (which Dr Lindstrom re-
gards as clearly Polyzoan) by Mr Billings and myself. Dr
Rominger, however, showed that it has " mural pores " of the
regular Favositoid type — a discovery which I have myself
verified — so that in place of being a Fistulipora, and, there-
fore, according to Dr Lindstrom, a Polyzoon, it is a true Per-
forate Coral. A position among the Favositidce has similarly
been now established as the right one for Stenopora, Lonsd.,
which includes forms so like Chcstetes and Monticnlipora in
general aspect as to have been commonly included under one
or other of the latter heads. Apart from mere superficial
appearances — which in this case speak at least as strongly for
a Coelenterate as a Polyzoan alliance — there is nothing in the
actual structure of Montiatlipora which would not entirely
agree with its being a coral. The only point which could be
mentioned which would in any fundamental manner distinguish
the internal structure of a Monticnlipora from that of, say,
Tetradium or Heliolites, is the absence in the former of septa.
I do not, however, attach any weight to this, partly because
some undoubted corals are equally without septa, partly because
the septa in Heliolites and its allies are now known by the
researches of Moseley to be only " pseudo-septa," and partly
because I do not think that any important change in classifica-
tion should be based upon a merely negative character. On
the other hand, there are strong resemblances between Mon-
tiaUipora and its allies and various undoubted corals — prin-
cipally, perhaps, the HelioporidcB. Thus the " tabulae " of the
Monticuliporoids are in all respects similar to those of such

T

2 90 TABULATE CORALS.

undoubted corals as Favosites among the Zoantharia, and
Heliolites among the Alcyoiiaria. Again, there is the import-
ant character that the corallum of the MonticuHporoids can be
shown to be almost always (I expect, always) dimorphic, con-
sisting of two distinct sets of corallites, of different sizes, and
mostly with a different internal structure. This last character
reminds us so strongly of the HclioporidcB — to which there
are other mentionable points of likeness — that I am at present
disposed to regard the Monticuliporidce as an ancient group
of the Alcyonaria.

As for the relations of Monticulipora to other types of the
so-called " Tabulate Corals," the genus is separated from all
the Favositidce, including the similar-looking Stenopora, Lonsd.,
by the possession of imperforate walls to the corallites.^ Ad-
mitting the absence of mural pores, in the want of direct evi-
dence to the contrary, we have only to compare Monticulipora
with a very limited number of types, of which the most im-
portant is ChcBtetes of Fischer. From this latter the present
genus is sufficiently distinguished by the non-amalgamation of
the walls of contiguous corallites, by the want of the curious
vertical ridge which is found in the interior of many of the
corallites of ChceteteSy and by the possession of two sets of
corallites in the corallum, one set of tubes being commonly
disposed in special groups. From Tetradium, Dana, Monti-
ailipora is sufficiently distinguished by its total want of septa
and by the dimorphic structure of the corallum. To Heliolites
and its allies the various types included under the general
name of Monticulipora present a considerable alliance, especi-
ally if we compare the structure of such a form as Fistulipora
[Callopora) incj^assata, Nich., with that of a form like Propora
tztbulata, E. and H. The absence of septa is, however,
sufficient to distinguish Monticulipora from the Heliopo7^idcs.

^ As before remarked, it is not impossible that "mural pores" may yet be demon-
strated to exist in Monticulipora. This is the more likely, if we remember that
these openings have as yet been absolutely demonstrated in only two species of
Stenoporaj so that some exceptionally well preserved specimen, or some lucky sec-
tion, may bring them to light in the MonticuHporoids at any time.

GENERA OF CH.ETETTD^ AND MONTICULIPORIDM. 291

From Prasopora, Nich. and Eth., jun., Montuulipora is dis-
tinguishable only by the very peculiar structure of the tabulae
of the former. Lastly, I need not attempt to differentiate from
Montictilipora the types known by the names of Dekayia, E. and
H., Constellaria, Dana, and Fistulipora, M'Coy [ = Callopora,
Hall), as I shall include all these under the former genus, re-
taining their titles as of subgeneric value, and shall, therefore,
speak of them at greater length hereafter.

The number of forms included under the comprehensive
title of Monticulipora, D'Orb., is so large, and the variations
in the minute structure of these are so important, that the
genus must of necessity be split up into sections, which may
be distinguished by separate names. It is impossible here for
me to give anything like a full account of my researches into
this subject, and I shall, therefore, content myself with simply
giving a brief summary of the general conclusions at which I
have arrived, together with short descriptions of some illustra-
tive species of the genus. Taking the intimate structure of
the corallum as the sole reliable basis for the subdivision of the
genus, I propose to include under the general name of Monti-
culipora, D'Orb., the following six subgeneric groups, which
will be best designated by special titles, and some of which
have been previously described as distinct genera.

I. Heterotrypa, Nich. — Corallites of two or sometimes of
three kinds ; the larger ones subpolygonal, partially separated
by the development of numerous smaller circular or irregularly-
shaped tubes, of which there is no more than a single row.
Walls thickened towards the mouths of the tubes. Tabulae
conspicuously more numerous in the smaller tubes than in the
larger ones. Type of the group the Monticulipora mammulata,
D'Orb. (which is also the type of the whole genus).

II. Dekayia, Edwards and Haime. — Corallites of two kinds,
the larger tubes with thin walls, polygonal in shape, and pro-
vided with well-developed tabulae. The smaller tubes isolated
by the larger corallites, apparently destitute of tabulae, their
walls greatly t^hickened, and appearing on the surface as so

292 TABULATE CORALS.

many detached spiniform processes placed at the angles of
junction of the larger tubes. Type of the group, Dekayia
aspera, E. and H.

III. CoNSTELLARiA, Dana. — Corallites of two kinds, the
larger ones circular or oval, with well-developed walls, which
become somewhat thickened as the calices are approached, the
tabulae being few in number and developed chiefly in the
outer portions of the corallum. Small corallites developed at
the angles of junction of the larger tubes, and more especi-
ally in the depressed centres of closely-disposed stellate areas,
which project above the general surface as conspicuous star-
shaped elevations. Walls of the small corallites imperfectly
developed, their shape being angular, or subangular, and their
tabulae being numerous and sometimes subvesicular. Type of
the group, Constellaria anthcloidea, Hall.

IV. FisTULiPORA, M'Coy (= Callopora, Hall). — Corallites
of two kinds, the larger ones circular or oval, with few and
remote tabulae, but with well-developed walls, which are not
thickened towards the mouths. Small corallites completely
isolating the larger tubes, round which they are developed in
one or more rows, with numerous tabulae, which sometimes
become vesicular by imperfection of the walls of neighbouring
corallites. The shape of the smaller tubes is markedly angular
(sometimes round ?) ; and though they may be specially de-
veloped in star-like areas, these areas never project as stellate
elevations above the general surface. Type of the group,
Fist2ilipo7'a 7nmor, M'Coy.

V. DiPLOTRYPA, Nich. — Corallites of two kinds, the larger
ones thin - walled throughout, conspicuously polygonal, with
comparatively few and remote tabulae, which occasionally are
developed in a peculiar bilateral manner, so that the two halves
of the tube are provided with tabulae of a different kind and
form. The large corallites are usually or always aggregated
at special points into conspicuous clusters (" monticules "), but
they are at the same time scattered indiscriminately through
the entire colony, and except where forming the groups just

GENERA OF CH.ETETID^ AND MONTICULIPORID^. 293

alluded to, they are partially separated by the intervention of
the smaller corallites, which are always angular in shape, have
thin walls, are never so far developed as to completely isolate
all the larger tubes, and are always provided with more nu-
merous and more closely set tabulae than is the case in the
latter. Type of the group, Monticulipoi-a petropolitana.
Pander.

VI. MoNOTRYPA, Nich. — Corallites of two kinds, which are
not conspicuously different from one another. The larger
tubes aggregated into clusters or " monticules," and very
slightly differing in size from the smaller ones. The smaller
tubes occupying all the spaces between the monticules. All
the corallites, of both kinds, uniformly thin-walled, regularly
polygonal, and similarly tabulate, the tabulae being remote and
few in number, and not uncommonly disposed at correspond-
ing levels in contiguous tubes. Type of the group, Moriticuli-
pora iChcstetes) undulata, Nich.

Sub-genus Heterotrypa, Nich., 1879.

This section includes many of the most typical and most
familiar of the species oi Monticulipora, comprising among them
the M. mammulaia, D'Orb., which, as the species first on the
list of MonticuliporcB given by D'Orbigny (Prodr. de Paleont.,
p. 25), has the right to be considered as the type of the whole
genus. In addition to M. mammulata, D'Orb., we must place
here M. raj7wsa, E. and H. (PI. XIII., figs. 2-2 a), M. rugosa,
E. and H., M. frondosa, D'Orb., M. Jamesi, Nich., M. monili-
formis, Nich., M. tumida, Phill., M. gracilis, James, and various
other more or less certainly established species. In all these
forms the corallum is conspicuously dimorphic (sometimes tri-
morphic), and consists of two sets of corallites of different sizes.
The larger tubes are subpolygonal or sometimes rounded in
shape, and are more or less conspicuously thickened towards
their mouths, while they usually possess few and remote
tabulae, or may be in great part devoid of these structures.

294 TABULATE CORALS.

They are usually to some extent contiguous ; but they are
always partially separated by the corallites of the smaller series,
which are also subpolygonal or rounded, and more or less
thickened towards their mouths. Sometimes (as in M. fron-
dosa, D'Orb., M. tumida, Phill, &c.) many of the smaller
corallites become abnormally thickened, so as to constitute a
third series, in which tabulae do not appear to be developed,
and which present themselves on the surface as a series of
blunt spines. In other cases — whether or not spiniform coral-
lites are present — the small corallites are more closely tabulate
than the larger ones, and are thus easily recognised in longi-
tudinal sections (PL XIII., figs, i <5 and 2 a). The general
characters of the MoitticuliporcB of this section will be best
understood from the following very brief descriptions of M.
ma7fimtdata, D'Orb., and M. ramosa, D'Orb.

Monticulipora (Heterotrypa) mammulata, D'Orb.

(PI. XIII., figs. I - I ^.)

Monticulipora manwiulata, D'Orbigny, Prodr. de Paleont., t. i. p. 25, 1850.
Chcetetes inammulaius, Edwards and Haime, Pol. Foss. des Terr. Pal., p. 267,

PI. XIX., fig. I, 185 1.
Montiadipora J7iammulata, Edwards and Haime, Brit. Foss. Cor., p. 265,

1854.
Chcetetes mammulatus, Nicholson, Quart. Journ. Geol. Soc, vol. xxx. p. 508,

PI. XXX., figs, z-z o^ 1874 ; and Pal. of Ohio, vol. ii. p. 207, 1875.

Spec. Char, — Corallum in the form of thin undulated expan-
sions, from two to four lines in thickness, consisting of two
layers of corallites, which diverge from an imaginary central
plane, to open on both sides of the frond. Surface covered
with well-marked " mamelons " placed at intervals of from half
a line to a line, and composed of corallites, which may be
slightly larger than the average, and which sometimes have
their calices closed by a calcareous membrane. Large or
average corallites polygonal, their walls but slightly thickened
towards their mouths, from eight to ten occupying the space of
one line. Small tubes not very numerous, wedged in among

GENERA OF CH.ETETID^ AND MONTICULIPORIDyE. 295

the larger corallites, and generally subpolygonal or angular in
shape. Large corallites with few and remote tabulae ; small
corallites closely tabulate.

Obs. — This species is so well known that I need only make
a few remarks upon its minute structure, as elucidated by thin
sections. Both tangential and vertical sections (the latter taken
at right angles to the plane of the frond) show that the coral-
lum is really dimorphic ; though the mere examination of the
surface with a lens, except in occasional specimens, would lead
one to conclude that small tubes are almost wantingf. Tanofen-
tial sections (PI. XIII., figs, i and i a) show, however, that
there exists really a fair number of small tubes scattered among
the larger corallites in an indiscriminate manner ; and vertical
sections (PI. XIII., fig. 1 b) prove that these are really special
corallites, as they are much more closely tabulate than the
ordinary corallites. There seems also generally to exist a very
small number of thickened spiniform tubes, easily recognised
in tangential sections by their circular outline and thick dark
margins ; though I have not been able to detect spines on the
surface. The corallites which occupy the " mamelons " cer-
tainly look a little larger, as a rule, than the average ; but as
they cannot be recognised in thin sections, I suspect this is an
illusory appearance, due to their greater nearness to the eye of
the observer. Their calices may be open, or may be closed by
a thin calcareous m.embrane, and they often have minute tubes
intercalated among them. The walls of the corallites, both
large and small, are slightly but unmistakably thickened by
a deposit of light-coloured sclerenchyma, which increases in
amount as the calices are approached (PI. XIII., fig. i a) ; but
in the limited extent of thickening, as well as in the compara-
tively small number of the smaller corallites, M, mammulata
shows itself to be not nearly such a characteristic member of
the section Heterotrypa as M. ramosa, D'Orb., M, frondosa^
D'Orb., M. Jamesi, Nich., or M. ticmida, Phill.

Formation and Locality. — Abundant in the Cincinnati group,
Cincinnati, Ohio.

296 TABULATE CORALS.

Monticulipora (Heterotrypa) ramosa, Edwards and Haime.

(PI. XIII., figs. 2, 2 a.)

Monticiilip07-a ratnosa, D'Orbigny, Prodr. de Paleont., t. i. p. 25, 1850.
ChcBtetes ramostis, Edwards and Haime, Pol. Foss. des Terr. Pal, p. 266,

PI. XIX., figs. 2, 2 a, 185 1.
Mo7iticulipora ramosa, Edwards and Haime, Brit. Foss. Cor., p. 265, 1854.
Chcetetes Dalei, Nicholson, Quart. Journ. Geol. Soc, vol. xxx. p. 501, PI.

XXIX., figs. 1, I <7, 1874; Pal. of Ohio, vol. ii. p. 192, PL XXI., figs.

I, I a, 1S75.
Chcetetes ramosus, Nicholson, Ann. Nat. Hist., ser. 4, vol. xviii. p. 88, 1876.

Spec. Char. — Corallum dendroid, of cylindrical or elliptical
branches which divide dichotomously, and vary from one to
three or four lines in diameter. Corallites markedly divided into
two series, the larger ones being rounded or elliptical, about a
seventh or an eighth of a line in their long diameter, and open-
ing on the surface by subpolygonal calices, which have some-
what thickened margins. The small corallites are excessively
numerous, surrounding the larger tubes in a single row, and
often completely isolating them, their shape and size being very
variable. In internal structure, both sets of corallites are
traversed by complete horizontal tabulae, which are much more
numerous in the small tubes than in the large ones. Walls
thickened towards the mouth. Surface covered with conical or
somewhat elongated " mamelons," placed at intervals of from
half a line to a line, and not occupied by corallites of specially
large or small dimensions.

Obs. — The external characters of this species are too well
known to require further remark here ; but we may note the
following features in the intimate structure of the corallum, as
shown in thin sections. In thin tangential sections (PI. XIII.,
fig. 2) the most striking appearance is the conspicuous division
of the corallites into two sets of tubes, large and small, and the
great development of the latter. The large tubes are very
uniform in size, generally oval or circular in shape, and mode-
rately thick-walled ; the thickening of the wall, however, never

GENERA OF CIEETETID.E AND MONTICULIPORID^. 297

proceeding to the extent that obtains in forms such as ]\I.
{Hete7'otrypci) Jainesi^ Nich., M. {Heterotiypa) ttmiida, Phill.,
and alHed types. The small corallites are very variable in
size and form, and are principally developed at the angles of
junction of the large tubes ; but they are commonly so numer-
ous as to form a complete zone round the large corallites,
though such a zone never consists of more than a single row.
Vertical sections (PI. XI II,, fig. 2 a) show that the internal
structure of the large and small tubes is conspicuously different;
both sets of corallites being traversed by complete horizontal
tabulae, which are greatly more numerous in the small tubes
than in the large ones. The " monticules " do not appear, as a
rule, to differ in structure from the general mass of the corallum,
but they seem sometimes to comprise a larger proportion of
small tubes than is usually the case in the intervening parts
of the skeleton. The internal structure oi M. (^Heterotrypd)
rugosa, E. and H., as I have elsewhere pointed out (Ann. Nat.
Hist, sen 4, vol. xviii. p. 88), appears to be essentially the
same as that of M. ramosa, D'Orb. ; and the two are probably
but varietal forms of a single species. The only difference
between the two, in fact, is to be found in the marked trans-
verse elongation of the " monticules " of the former.

o

Formation and Locality. — Common in the Cincinnati group,
Cincinnati, Ohio.

Sub-genus Dekayia, Edwards and Haime, 1851.
(Pol. Foss. des Terr. Pal., p. 277.)

This section of the genus Monticulipora includes only one
or two types, which were separated by Edwards and Haime as
a distinct genus under the name of Dekayia, but which I regard
as forming a group of no more than sub-generic value. In the
general nature and structure of the corallum the species of De-
kayia entirely resemble the dendroid forms of Monticulipora,
and the only feature that would strike the observer is that the

2 98 TABULATE CORALS.

surface of the former is studded with Httle quadrangular spines
or columns, interspersed in great numbers among the ordinary
tubes of the corallum. The structure of these columns was
first investigated by me by means of thin sections (Ann. Nat.
Hist, sen 4, vol. xviii. p. 93, PI. V., figs. 12 and \2 d)\ but it
is only through more recent and more complete investigations
that I have been able to arrive at any definite conception as to
their real nature. I am, however, now satisfied that the coral-
lum in Dckayia is truly dimorphic, that the surface-columns are
the homologues of the spines which are so abundantly de-
veloped in M. {Heterotrypd) tiimida, Phill., M. (Heterotrypa)
moniliformis, Nich., and other forms of Monticulipora, and
that these structures are properly to be regarded as a pecu-
liarly modified series of corallites. Taking this view of the
subject, the species of Dekayia are principally separable from
the spiniferous species of Montiadipoj^a {Heterolrypa) by the
fact that in the former the spines are much reduced in number
and increased in size, while they are always isolated by the
large tubes, these latter being of one kind only. The more
minute characters of the sub-genus will appear from the follow-
ino- very brief description of Dckayia attrita, Nich., the only
species with which I am acquainted, and which is very prob-
ably identical with the type-species D. aspcra, E. and H.

Dekayia attrita, Nich.

(PI. XV., figs. I - I ^.)

Chcetctes atfriti/s, Nicholson, Quart. Journ. Geol. Soc, vol. xxx. p. 503, PI.
XXIX., figs. 4, 4^!, 1874; Pal. of Ohio, vol. ii. p. 194, PL XXL, fig. 4,

1875-
Dekayia attrita, Nicholson, Ann. Nat. Hist, ser. 4, vol. xvm. p. 93, figs. 12,

12 a, 1876.

Spec. Char. — Corallum dendroid, of subcylindrical branches,
varying from four to seven lines in diameter, and dividing at
short intervals. Corallites for the most part polygonal, thin-
walled, and sub-equal, from eight to ten in the space of one

GENERA OF CH.ETETID.E AND MONTICULIPORID^. 299

line. Interspersed between the large corallites, generally at
the junction of four or six of the latter, are conical or sub-
quadrangular eminences or tubercles (PI. XV., fig. i a),
placed at intervals of from a fifth of a line to half a line.
These eminences are the upper ends of curved and thick-
walled tubes, which appear to be closed above, and which are
not traversed by tabulae, but which are to be regarded as
specially modified corallites. The normal corallites are crossed
by horizontal, complete, and remote tabulae.

Obs. — This species seems to be distinct from D. aspera,
E. and H., its size apparently being less, and its form more
strictly dendroid ; but the latter is insufficiently described, and
it is quite possible that D, att7Hta is merely a variety of it.
In internal structure, tangential sections of D. atliHta (PI.
XV., fig. I b) show that the bulk of the corallites are thin-
walled, polygonal, and approximately equal in size, while in-
terspersed among these and completely isolated by them are
the thick-walled tubes, which give rise to the surface-columns.
The apices of these columns (PI. XV., fig. i a) certainly seem
to be solid and imperforate ; but when divided transversely a
little below the surface, they are seen to be composed of dense
and dark-coloured sclerenchyma, deposited in successive con-
centric lamellae in the interior of the originally angular tube,
and almost always exhibiting a small circular central canal.
Tangential sections also show occasional small angular coral-
lites intercalated among the larger ones, and we may reo-ard
these as spiniform corallites in which the walls are still un-
thickened. Vertical sections (PI. XV., fig. i c) show that the
corallum is mainly made up of the normal corallites, which in
the axis of the branches are provided with very delicate and
undulated walls, and are free from tabulae. As the corallites
curve outwards towards the surface, their walls become slightly
thickened, and a few remote and complete tabulae are developed
in their interior. The spines only extend inwards from the
surface to the point where the corallites bend downwards to
the axis of the branch, and they are seen to consist of a central

300 TABULATE CORALS.

non-tabulate tube, bounded by very thick dense walls. In
some cases, also, the central tube of the spines seems to be
continued to the actual surface, though I have failed to detect
openings in the surface-columns. I have, however, no doubt
but that the surface-columns are primitively perforated, and
that the spines are, therefore, genuine corallites, though of a
peculiar kind. The forms to which Dekayia shows the greatest
affinity are those like Montic2ilipora {Hetcrotiypa) moitilifoinnis,
Nich., but in these the spiniform corallites are much more ex-
tensively developed. I must, however, defer further considera-
tion of this subject till I am able to separately discuss the very
remarkable features exhibited by the spines of various of the
Monticuliporoids, as well as of certain species of Stenopora.

FormatioJi and Locality. — Rare in the Cincinnati group,
Cincinnati, Ohio.

Sub-genus Constellaria, Dana, 1846.

(Zooph., p. 537, 1846.)

Steltipora, Hall, Pal. N.Y., vol. i. p. 79, 1847.

This section includes forms which, in many respects, are
very nearly allied to Fistulipora, M'Coy, but which exhibit
some very peculiar features. Some of the structural peculiari-
ties of the type will require for their elucidation much more
extended investigation than I have as yet been able to bestow
upon them, and the following must be regarded as little more
than a general and provisional statement as to the characters
of the sub-genus. The corallum in ConstellatHa is obviously
and conspicuously dimorphic, the most striking of its features
being the existence of a series of close-set, star-shaped, de-
pressed areas (" maculae "), which are occupied by the smaller
tubes, and which are surrounded each by a radiating circle of
short elevated ridges carrying large tubes (PI. XIV., fig. 5).
The large tubes also occupy, mainly or wholly, the spaces be-
tween the star-shaped monticules, and each is oval or circular

GENERA OF CH^TETID.E AND MONTI CULIPORID.E. 301

in shape, and surrounded by a strong and thickened wall, the
intervals between them being occupied by the smaller tubes.
The large corallites are traversed by a few remote tabulae,
and the small tubes are closely tabulate, their tabulae often be-
coming subvesicular, while their walls become obsolete. The
above characters will be more fully brought out by a brief
description of the type-species, the Constellaria antJieloidea,
Hall, of the Lower Silurian of America.

Constellaria antheloidea, Hall.

(PI. XIV, figs. 5,5/;.)

Stellipora antheloidea, Hall, Pal. N.Y., vol. i. p. 79, PI. XXVI., figs. 10 a,
\o c, 1847.
„ antheloidea, D'Orbigny, Prodr. de Paleont., t. i. p. 22, 1850.

Constellaria aniheloidea, Edwards and Haime, Pol. Foss. des Terr. Pal.,
p. 279, PI. XX., figs. 7- 7 <^, 1851.
„ aniheloidea, Nicholson, Pal. of Ohio, vol. ii. p. 214, 1875.

,, aniheloidea, Nicholson, Ann. Nat. Hist., ser. 4, vol. xviii. p. 92,

PI. v., fig. 10, 1876.

Spec. Char. — Corallum in the form of palmate, or sublobate,
flattened expansions, two or more inches in height, with a thick-
ness of from one and a half to two lines, and composed of
corallites which radiate from an imaginary central plane to
open on all unattached parts of the skeleton. Surface (PI.
XIV., fig. 5) with numerous stellate areas, a line or less In
diameter, and placed about half a line or rather more apart,
each consisting of a depressed central space, surrounded by
from six to eight prominent and radiately- placed elevated
ridges. Corallites of two kinds, large and small. Large coral-
lites oval or circular, about one-tenth of a line in diameter, with
strong bounding-walls, occupying the general surface of the
corallum, and specially aggregated on the elevated ridges of
the star-shaped monticules, in the central depressed areas of
which they are wanting. Small tubes, apparently really sub-
angular, occupying all the interspaces between the larger oval

302 TABULATE CORALS.

tubes, and especially aggregated in the central depressed areas
of the monticules, and in the star-like prolongations which run
out from these ; their walls thin and apparently often wanting.
Large corallites with few remote tabulae ; small corallites with
very numerous close-set tabulae, which often anastomose with
those of neighbouring tubes.

Obs. — Passing over the obvious and well - known external
features of the corallum in Constellaria antJieloidea, I may
make a few remarks upon the appearances presented by thin
sections. Tangential sections (PI. XIV., fig. 5 a) present some
peculiar difficulties of preparation, owing to the irregularity of
the surface due to the monticules, but when properly made,
they are very instructive. They exhibit both sets of corallites,
the larger being conspicuous both by their size and their cir-
cular or oval form, and by the fact that each is bounded by a
thick and apparently double wall. It is only in the stellate
ridges of the monticules that the large corallites are at all ex-
tensively in contact ; but in the intervals between the monti-
cules they are only partially contiguous, and are separated
by more or less extensive interspaces. These interspaces, as
well as the central areas of the monticules and the branching
diverticula therefrom, are occupied by the smaller corallites.
The appearances presented by these vary under different cir-
cumstances, and in different parts of the section ; and I am not
at present able to explain some of the appearances which they
exhibit. They are best studied in the central depressed areas
of the monticules, and in their most perfect condition they are
seen to be angular in shape, and to be bounded by thin and
delicate walls, which, however, are often partially imperfect,
thus allowing neighbouring tubes to communicate. In other
cases, the divisional walls between the small corallites seem
wholly wanting, and the central areas of the monticules exhibit
simply minute rounded and remote pores, together with other
peculiarities which I must leave for future examination. In
the interspaces between the large tubes, also, the smaller tubes
only rarely seem to possess complete bounding walls, and here,

GENERA OF CH.ETETID.E AND MONTICULIPORID^. 303

as in the monticules, there is the curious feature that the cavi-
ties of the smaller corallites seem to be very commonly obliter-
ated by a secondary deposit of light-coloured sclerenchyma.
Vertical sections (PI. XIV., fig. 5 b) render it certain, however,
that whether or not their walls are developed in a complete
form, the interspaces between the larger tubes and the central
areas of the monticules are alike uniformly occupied by the
smaller corallites. In sections of this kind, we see that the
large corallites exclusively occupy the central part of the cor-
allum, in which region they are thin-walled, and possess few or
sometimes no tabulse. As they bend outwards, in approaching
the surface, their walls become thicker, and the tabulae, though
still very few and widely remote, become somewhat more nu-
merous. The small corallites are only developed in the inter-
spaces between the larger tubes in the outer portion of the
course of the latter, so that they occupy only a superficial zone
of the corallum ; and they are at once recognised not only by
their small size, but also by their very numerous and close-set
tabulae. Sections of this kind further demonstrate that the
walls of the smaller tubes are really often wanting, though at
other times clearly recognisable ; their tabulae, in the former
case, becoming laterally coalescent and often more or less ex-
tensively vesicular. This latter feature is particularly observ-
able in the aggregations of the smaller corallites which consti-
tute the central depressed areas of the monticules.

The affinities of Constellaria seem to be clearly with Fis-
tulipora, M'Coy, in which, likewise, the bounding- walls of the
smaller tubes may in some forms become so far obsolete as to
allow of the tabulse assuming a completely vesicular structure.
The sub-genus is, however, sufficiently separated from Fistuli-
pora by the much less complete development of the small tubes,
which in the latter type always completely encircle and isolate
the larger tubes ; while the star-shaped form of the monticules
is another well-marked distinguishing character.

Formation and Locality. — Rare in the Cincinnati group,
Cincinnati, Ohio.

304 TABULATE CORALS.

Sub-genus Fistulipora, M'Coy, 1849.

(Ann. and Mag. Nat. Hist, ser. 2, vol. iii. p. 130.)

Callopora, Hall. Pal. N.Y., vol. ii. p. 144. 1S52.

The corals of this group were separated by M'Coy to form
his genus Fishdipora, with the following generic diagnosis : —

" Corallum encrusting, composed of long, simple, cylindrical,
thick-walled tubes, the mouths of which open as simple, equal,
circular cells on the surface, and having transverse funnel-
shaped diaphragms at variable distances ; interval between
the tubes occupied by a cellular network of small vesicular
plates." The type of the genus is the F. minor, M'Coy, of
the Carboniferous Limestone of Derbyshire.

At a later period, Professor Hall proposed the name of
Callopora for certain Upper Silurian corals, with the following
generic diagnosis : —

" Ramose or encrusting species of corals, having a columnar
structure ; cells tubular, with the apertures circular or petaloid,
not contiguous, and having the intermediate spaces occupied
by angular cell-like openings which are transversely septate ;
tubular cells rarely septate."

The identity of Fishdipora, M'Coy, and CaUopoj^a, Hall,
has long been more than suspected, the chief difficulty in the
way of uniting the two being that M'Coy states that the tabulae
in the large corallites of Fisttdipora have infundibuliform
tabulae, while Hall describes radiating septa as sometimes
present in the type-species of Callopora. M 'Coy's statement
as to the tabulee is, however, clearly based upon imperfect
observation, and this is also almost certainly the case as to the
alleged occurrence of septa. At any rate, having carefully
examined specimens of F. minor, M'Coy, the type of the genus
Fistulipora, and having compared these with typical examples
of Hall's genus Callopora from the Silurian and Devonian
rocks of North America, I am satisfied that the two are un-

GENERA OF CHyETETID^ AND MONTICULIPORID^. 305

questionably congeneric, and that both must be united under
the older name oi Fistulipora, M'Coy. The intimate structure
of the genus is also so nearly allied to that of certain Monti-
culiporcE, as well as to Consteliaria, that I think it is best to
regard Fistulipora as only a sub-genus of MonticiUipora.

The species of Fistulipora agree in the possession of a
dimorphic corallum, composed of two sets of corallites of con-
spicuously different sizes, and bearing definite relations to one
another. The large corallites are markedly circular or oval,
in most forms, and are isolated in position, while their cavities
are intersected by few and remote horizontal tabulae, these
structures being occasionally partially absent. The smaller
corallites are distinctly angular in form, and surround the
larger tubes completely, there being sometimes one and some-
times two rows between any given pair of the latter. The smaller
corallites are furnished with numerous and close-set tabulae, and
may or may not be bounded by complete walls. In the former
case the tabulae are complete and horizontal, whereas in the
latter case they anastomose with one another, and give rise to
a tissue of convex lenticular vesicles, the variations observable
in this respect being precisely parallel with those which obtain
respectively in Heliolites and Propora. The walls of the cor-
allites of both sets are thin, and are not conspicuously thickened
towards their mouths. It should also be borne in mind that
the interstitial and closely-tabulate corallites are sometimes
equal in size to the round and remotely-tabulate corallites which
they surround ; so that in speaking of the former as the " small "
corallites, we only employ this term in a conventional sense,
as indicating their homology with the small tubes of the Mon-
ticuliporoids generally. The corallum in Fistulipora often
exhibits " maculae " or definite areas occupied by the smaller
corallites only. These maculae may be stellate in shape ; but
they are never elevated above the surface or surrounded by
radiating elevated ridges, as is the case in Consteliaria. Lastly
while the large rounded tubes always open the surface by open
calices, the intermediate angular tubes often have their mouths

3o6 - TABULATE CORALS.

closed In the adult condition by a thin calcareous membrane.
In no case are septa present.

From the Heliolitidcs, FistuUpora Is separated mainly by the
total absence of septa In the latter ; but, as has been pointed
out, there Is a striking resemblance in general structure between
certain species of FisttUipora, on the one hand, and the species
oi Pi'opora and Heliolites on the other hand. " Mural pores"
have not been detected In any typical form of Fistidipora ; but,
as has been previously mentioned, Dr Rominger has shown
(Foss. Cor. of Mich., p. 29) that the coral described by Mr
Billings from the Devonian of Canada, under the name of
FistuUpora Canadensis, Is provided with perforate walls, and is
therefore a genuine Favositold type. We thus have a coral
which precisely resembles the normal forms of FistuUpora In
appearance, but which exhibits mural pores ; and It becomes,
therefore, a matter for future research whether or not these
structures occur In any other species now referred to FistuUpora.

The genus FistuUpora ranges from the Silurian to the Car-
boniferous, and I shall briefly describe the following three
species as illustrating its more characteristic features.

FistuUpora minor, M'Coy.

FistuUpora minor, M'Coy, Ann. Nat. Hist, ser. 2, vol. iii. p. 130, 1849;
and Brit. Pal. Foss., p. 79, 185 1.

Spec. Char. — Corallum in the form of thin, irregular crusts,
attached parasitically at one point or over the whole lower sur-
face, attaining a thickness of two or three lines. Large corallites
oval or circular, about a fifth of a line In their long diameter ;
separated by Interspaces of about their own width, less or
more ; and with few or no tabulse, these structures, when pres-
ent, being horizontal. Small tubes angular, of variable shape,
generally about a tenth of a line In diameter, each of the larger
tubes being surrounded by a single circle of the smaller coral-
lites, so that there exist two rows of the latter between any

GENERA OF CHyETETIDyE AND MONTICULIPORID^. 307

given pair of the former. The small tubes are closely tabulate,

but by the imperfect development of their walls the tabulse
coalesce to a larger or smaller extent, and thus give rise to a
vesicular tissue, composed of lenticular vesicles, which have their
convexities directed upwards.

Fig. '},'^.—Fistulipora minor, M'Coy. A, Portion of a tangential section, showing the rounded
large tubes {a, a) and the angular interstitial tubes (/', /') ; B, Portion of a vertical section,
showing two of the large tubes, almost free from tabulce («, a), and the interstitial vesicular
tissue formed by the tabulce of the smaller tubes (h, b). The sections are enlarged twenty-
five times.

Obs. — I am indebted to my friend Dr Ramsay H. Traquair
for a specimen from the Carboniferous rocks of Scotland which
he had previously, and unquestionably correctly, identified with
the Fistulipora minor of M'Coy. The surface of this specimen
is poorly preserved, the prominent round mouths of the larger
tubes being alone shown ; and I am unable to determine
whether or not "maculae" are present, though I see no traces
of these in thin sections. The internal structure is fully shown
by thin tangential and vertical sections (fig. 39, a and b) ; but I
need add nothing further to the description given in the specific
diagnosis.

In its minute characters, F. minor is nearly related to F.
incrassata, Nich., from the Devonian of North America. This

3o8 TABULATE CORALS.

is especially shown by the fact that the tabulae of the angular
corallites in both species give rise to a series of convex lentic-
ular vesicles {compare fig. 39, b, and PI. XV., fig. 3 b). The
large round corallites of F. incrassata are, however, nearly
twice as large as those of F. minoi% and are only separated by
a single row of angular tubes, while they are provided with
more numerous tabulae, these features alone being sufficient to
establish the specific distinctness of the two forms.

Formation and Locality. — In the Lower Carboniferous Lime-
stone of Cousland, near Edinburgh. Collected by Dr R. H.
Traquair.

Fistulipora incrassata, Nich.

(PI. XV., figs. 3-3/^.)

Callopora incrassata, Nicholson, Geol. Mag., Dec. ii. vol. i. p. 13, PI. II., fig. i,
18743 Rep. Pal. of Ontario, p. 61, fig. 19, 1875.

Spec. Char. — Corallum sometimes forming thin crusts, at-
tached parasltically to foreign bodies, or partially epithecate
below, or at other times constituting irregular masses of con-
siderable size. Large corallites, oval or pyriform in section,
one end being wider than the other, and the junction between
the two commonly being marked by two small laminar inflec-
tions of the wall of the tube on opposite sides. The large
tubes are about a third of a line in their long diameter, and
their calices project slightly above the general surface, while
they are completely separated from one another by the inter-
mediate " small " corallites. These latter are angular in form,
and there is never more than a single row of them between any
given pair of the large corallites. Their mouths are seldom dis-
tinctly shown, and are often closed by a thin calcareous mem-
brane. At intervals the surface shows star-shaped depressed
"maculae," which are entirely occupied by the angular coral-
lites, and which are often covered by a superficial calcareous
pellicle. Owing to the variable shape of the angular corallites,

GENERA OF CH.ETETID^ AND MONTICULIPORID^E. 309

'mWtB

their size is corresponding-ly variable ; but they are generally
of smaller diameter than the round tubes. The large corallites
are intersected by a few, remote, horizontal tabulae ; while the
tabulae of the angular interstitial corallites are much more
closely set, and become amalgamated in contiguous tubes, so
as to give rise to a vesicular tissue, the lenticular vesicles of
which have their convexities directed upwards.

Ods. — I have reproduced here the original figures of this
species (fig. 40), though they are in some respects incorrect.
The real structure of the
corallum is, however, shown
in PI. XV., figs. 3 - 3 <^, from
which it will be seen that
its minute characters are in
the main similar to those of
Fistulipora 7nino7^, M'Coy.
It differs from this form,
however, in the larger size
of the round corallites, and
in the fact that any given
two of these are separated
by no more than one row
of the smaller tubes. Not
only are these latter mark-
edly angular in shape, but
they, thus, necessarily abut

on their opposite sides against the larger corallites. The large
tubes are not only oval, but they are wider at one end than the
other, and they usually exhibit the peculiar feature that there
exist two small inward inflections of the wall of the tube, which
are placed, one on each side, at a point situated about one-third
of the long diameter of the tube from its pointed end (PI. XV.,
fig. 3 a). Thin vertical sections (PI. XV., fig. 3 b) show that
the large corallites are intersected by a few complete horizontal
tabulae ; while the walls of the smaller tubes are imperfectly
developed, and their tabulae coalesce to constitute a series of

Fig. 40. — Fisiiilipora mcrassata, Nich. a, A
fragment, of the natural size ; b, A portion of
the surface enlarged, showing the mouths of
the two sets of corallites ; c, A portion of the
surface less highly magnified, showing one of
the star-shaped "maculae;" d. Vertical sec-
tion enlarged.

3IO TABULATE CORALS.

strongly convex vesicles. From the nearly allied F. prop oroides,
Nich., the present species is distinguished by its generally more
massive form, the inflections of the walls of the large corallites
above spoken of, and the fact that the tabular of the smaller
tubes coalesce to form a vesicular tissue.

Formation a7id Locality. — Common in the Hamilton Group
of Arkona, Ontario. I originally included under the name of
Callopora incrassata certain large and massive specimens from
the Corniferous Limestone of Ontario. Not having had, how-
ever, the opportunity of examining these microscopically, I do
not feel sure they are specifically identical with the Hamilton
examples, upon the characters of which the foregoing descrip-
tion is based.

Fistulipora proporoides, Nich.
(Fig. 41, and PL XV., figs. 2, 2 a.)

Spec. Char. — Corallum in the form of thin and extended,
often much contorted expansions, which have an average thick-
ness of about one line, and have the under surface covered by
a concentrically- striated epitheca, the corallites being nearly
vertical, and opening upon the upper surface. The large coral-
lites are oval or nearly circular, about one-fifth or one-sixth of
a line in diameter, and separated by interspaces of about the
same width. The " small " corallites are markedly angular,
only one row ever existing between contiguous round tubes,
and their size being often equal to, or even larger than, that of
the latter. On the surface the calices of the round tubes
appear as marked projecting apertures, while the calices of the
angular tubes appear to be usually closed in the adult condition
by a thin calcareous membrane. Maculae present or absent.
In internal structure the round tubes have very few or no
tabulae, and, when present, these structures are always com-
plete and horizontal. The " small " tubes are always bounded
by complete walls, and are intersected by comparatively
numerous horizontal, not vesicular tabulae.

GENERA OF CH.ETETIDyE AND MONTICULIPORID^. 311

Obs. — This beautiful species, in the essential features of its
organisation, is clearly nearly allied to the two forms previously
described, and especially to F. incrassata. It agrees more
particularly with this last in the comparatively large size and
markedly angular form of the interstitial corallites, and in the
fact that there is but one single series of these separating the
round tubes. In both species also the surface exhibits, alone
or principally, the projecting apertures of the round corallites
(PI. XV., figs. 2 and 2 a), the mouths of the angular intersti-
tial tubes seeming to be often closed by a thin calcareous mem-
brane. The form of the corallum, however, is in the present
species always that of a thin, often contorted expansion, the
under surface of which is clothed by a striated and plicated

Fig. 41. — FistnUpora proporoides, Nich. A, Part of a vertical section, enlarged twenty times,
showing the different tabulation of the two sets of corallites. is, Part of a tangential
section, showing the round and the angular corallites, enlarged twenty times : a, a, Round
or "large " corallites ; l>, b, Angular or " small " corallites.

epitheca ; the round corallites are strictly round or oval, and
are not contracted at one point ; the " maculae " are sometimes
obsolete ; and there is the striking internal difference that the
angular interstitial corallites are always limited by complete
walls, and are intersected by numerous horizontal tabulae, which
never assume a vesicular character (Fig. 41, a). This last-
mentioned feature, among other points of distinction, sufficiently

312 TABULATE CORALS.

separates the species from F. minor, M'Coy, this latter Hke-
wlse having a much greater development of the interstitial
corallites.

Formation and Locality. — Common in the Hamilton Group,
Canandaigua, State of New York.

Sub-genus Diplotrypa, Nich., 1879.

I propose this name as a subgeneric designation for a group
of MonticuliporcE, of which M. petropolitana, Pand., is the
type. The corallum in the forms in question is like that of
the sub-genus Heterotrypa in being conspicuously dimorphic ;
but all the corallites are markedly angular or pris7?iatic, while
their walls are remarkably thin and delicate, and their general
appearance resembles that of the corallites of Favosites. The
large corallites have few and remote tabulae, and are usually or
always aggregated at special points into clusters or " monti-
cules ; " but they are also scattered throughout the entire
colony, the bulk of which they compose. In the "monticules"
the large tubes are usually alone present, but in the other parts
of the corallum the larger corallites are partially separated by
the development of a larger or smaller number of small coral-
lites, which agree with the large ones in being angular in shape,
but differ in being provided with much more numerous and
close-set tabulae. The characters of the group will be best
elucidated by a brief consideration of the internal structure of
M. {piplotrypd) petropolita7ia^ Pand.

GENERA OF CH.ETETTD^ AND MONTICULIPORID^E. 313

Monticulipora (Diplotrypa) petropolitana, Pander.
(PL XIII, figs. 3-3 r.)

Favosites petropolitanus, Pander, Russ. Reiche, p. 105, PI, I., figs. 6, 7, 10, 11,

1830.
(Non ChcEtetes petropolitaiius, Nicholson, Quart. Journ. Geol. Soc, vol. xxx.

p. 510, PI. XXX., figs. 5-8, 1874; Geol. Mag. Dec. ii., vol. ii. p. 175,

1875; P^^- Ohio, vol. ii. p. 204, PI. XXI., figs. 14-14 b, 1875; Ann.

Nat. Hist., ser. 4, vol. xviii. p. 88, PI. V., figs. 6 - 6 a.) ^

Spec. Char. — Corallum discoid when young, but spheroidal,
or hemispherical when fully grown, the base being circular,
more or less deeply concave, and covered with a concentrically
striated epitheca, while the calices cover the whole of the upper
surface. The corallites are of two sizes, large and small, these
being uniformly interspersed with one another throughout the
entire colony, while the former also constitute small clusters or
monticules. The large corallites are about one-quarter of a
line in diameter, provided with uniformly thin and delicate
walls, not thickened towards the surface, and for the most part
very regularly hexagonal in shape. The small corallites are
wedged in at the angles of junction of the large tubes, which
they sometimes to a large extent separate from one another,
their diameter varying from a twelfth to an eighth of a line or
more. They resemble the large corallites in being uniformly
thin-walled and strictly angular, their shape being very variable,
but mostly oblong, square, or sub-triangular. Both sets of
tubes are provided with complete horizontal tabulae, which
increase in number towards the surface ; and the tabulae in the
smaller tubes are more numerous than in the lareer ones,
though this disproportion is not so marked as is usually the
case in the species of Monticulipo7'a.

Obs. — A great number of corals have been described or
quoted by different authors from the Lower Silurian deposits of

1 Beyond pointing out that the forms which I have previously considered and
described as M. petropolitana, Pand., are really distinct from the original Russian
type of the species, I have not thought it — for reasons to be subsequently given — of
any use to attempt to give a synonymy of this form.

314 TABULATE CORALS.

different parts of the world under the name of Montictilipora
petropolitaiia or Ckcstetes pctropoliiaims, Pand. In most cases,
however, the determination of particular specimens as belong-
ing to this species has been founded upon the well-marked
external form of the corallum and the general nature, often
with difficulty recognisable, of its surface characters. That
this should be the case was inevitable, seeing that the internal
structure of the corallum does not admit of being made out
properly save by means of carefully-prepared sections ; and,
further, that the minute characters of the genuine Russian types
of the species have never been, so far as I am aware, either
described or figured. Even now it can hardly be said that the
position of our knowledge is absolutely satisfactory, seeing that
Pander's type-specimens have not been subjected to minute
examination. I am, however, indebted to the kindness of my
friend Dr Lindstrom for specimens from the Lower Silurian
of Sweden, the identity of which with the original Favosites
petropolitanus of Pander hardly admits of doubt, seeing that
they are derived from a corresponding geological horizon and
from a neighbouring geographical area. These specimens I
have subjected to a careful microscopic examination, and the
characters which they afford I regard as those specifically
diagnostic of M. peti^opolitana, Pand. Starting with this basis,
it is at once clear that the mere external form and surface-
characters of the corallum are of no use at all in the deter-
mination of this species. Thus all, or almost all, of the corals
which I have myself examined and described from the Lower
Silurian rocks of North America, and which I have identified
with M. petropolitana on account of their general form and
appearance, turn out to be widely different from the similar-
looking Russian species in their internal structure. I shall
also describe specimens from the Devonian which on merely
external examination would unhesitatingly be referred to M.
petropolitana, but which, tested by the facts of their minute
structure, are specifically or even sub - generically different.
Considering, therefore, that almost all the determinations of

GENERA OF CH^TETID.E AND MONTICULIPORID.E. 315

M. petropolitana, in different deposits and in different countries,
have been based solely upon macroscopic investigation, and
that this is clearly insufficient for specific diagnosis, it has ap-
peared to me to be quite useless to give any synonymy of the
species. With our present knowledge, in fact, such a synonymy
would simply give us the information that certain authors had
identified from certain regions and formations corals which are
doubtless referable to MontiaiHpora^ in its wide sense, and
which resemble AI. petropolitana in form and habit.

In the Swedish specimens of M. petropolitana, Pand., which
I shall take as the type of the species, the corallum has the
well-known hemispherical or sub-globular form, its circular and
concave base being covered with a thin concentrically striated
epitheca (PI. XIII., figs. 3, 3 a). In thin sections (PI. XIII.,
figs. 3 b and 3 c) no feature is more striking than the ex-
treme delicacy and tenuity of the walls of all the coral-
lites. The walls are so thin that they appear as mere simple
and undivided dark lines, the originally duplex character of
the boundaries between contiguous corallites being entirely
lost. Nor, again, do the walls become in any way thickened
as the surface is approached. In this respect, therefore, there
is a marked and important difference in the structure of this
form as compared with the more normal types of Monticuli-
pora {Heterotrypa). In tangential sections (PI. XIII., fig. 3 b)
another marked peculiarity is the strictly angular form of all
the tubes, and the very regularly hexagonal or pentagonal
outline of the larger corallites. Each of the larger tubes is
usually in contact with a tube of the same series on one or
two sides, but the other faces usually abut against corallites of
the smaller series, these being generally oblong or quadrate
in shape. In vertical sections (PI. XIII., fig. 3 c) the two
sets of corallites are chiefly recognisable by the difference in
their respective sizes, their tabulation being more uniform
than is usual in the genus. The small corallites are, how^ever,
always to some extent more closely tabulate than is the case
with the large tubes.

3i6 TABULATE CORALS.

The nearest ally of M. {Diplotrypa) petropolitana with which
I am acquainted is one of the forms which I previously de-
scribed as Chcvtetes petropoliianus, from the Lower Silurian
rocks of North America. Now, however, that I know the
internal structure of the Russian species, I find that the
American specimens are specifically distinct, and I shall de-
scribe them under the name of M. {Diplotrypa) WJiiteavesii.
They are distinguished from M. peti^opolita7ia, Pand., by the
much closer tabulation of the small corallites, the peculiar
double tabulation of many of the large corallites, and the
form and size of the latter tubes. From the forms which I
shall here describe under the names of M. (Monotrypa) un-
dulata, and M. {Monotrypa) Winteri, the present species is
easily distinguished on minute examination ; for both the
former types are destitute of a series of small corallites
interspersed among the ordinary tubes of the colony, while
all the corallites are similarly and uniformly tabulate.

Formation and Locality. — Lower Silurian (Chasmops Lime-
stone), Ostragothia, Sweden. Collected by Dr Lindstrom.

Monticulipora (Diplotrypa) Whiteavesii, Nich.
(PI. XIII., figs. 4-4 <^, and PI. XIV., fig. i.)

C/icetdcs pctropolitanus, Nicholson, Quart. Journ. Geol Soc, vol. xxx. p. 510,

PI. XXX., figs. 5 - 8, 1875.
„ petropolitanus (pars), Nicholson, Pal. of Ohio, vol. ii. p. 204, PI. XXI.,

figs. 14, 14 b, 1875.
„ peiro_polita?ius, Nicholson, Ann. Nat. Hist., ser. 4, vol. xviii. p. 88, PI.

v., figs. 6, 6 a, 1876.
„ petropoUtanus (pars), Nicholson, Geol. Mag. Dec. ii., vol. ii. p. 175,

1875-
„ petropolitafiiis, Nicholson, Rep. Pal. of Ontario, p. 10, PI. IV., figs. 3
and 4, 1875.

Spec. Char. — Corallum discoid when young, hemispheric
when adult, often with the lateral margins widely extended,
the base being usually deeply concave, sometimes flattened,
and being covered by a concentrically striated epithecal plate.

GENERA OF CH.ETETIDyE AND MONTICULIPORID.E. 317

Corallites directed upwards nearly at right angles to the entire
basal plate, and opening upon the upper aspect of the colony.
Surface with scattered and very slightly raised " monticules "
composed of corallites slightly above the average in size.
Corallites of two kinds, large and small, the tubes of both
series intermlno^led throuorhout the entire corallum. Lar^e
tubes, mostly from a sixth to a fifth of a line in diameter,
more or less thin-walled, angular, often hexagonal, in shape,
and sometimes arranged in small groups or rosettes of four
or five tubes each. Small corallites very numerous and very
variable in size and form, but always thin-walled and angular,
and wedged into all the interspaces left between the large
tubes. In internal structure the large tubes may be simply
crossed by remote, delicate, complete tabulae ; but many of
them are divided by a vertical flexuous partition into two
compartments, the tabulae on the one side of this partition
being strongly curved, with their convexities directed up-
wards, while on the other side they are simply horizontal.
In the small tubes the tabulae are always very numerous,
close-set, and horizontal.

Obs. — In general form, the corallum of the present species
(fig. 42, and PI. XIII., figs. 4, 4 a) is generally quite like that

Fig. d,2. — Monticiilipom {Diplotrypd) Whiteavesii. A, Side view of the corallum, of the natural
size ; B, Transverse section of the corallum near its base, showing the thin-walled hex-
agonal corallites, enlarged. (This section cuts across the axial corallites close above their
origin, showing none of the small tubes, the appearances presented being thus quite unlike
those exhibited by a taitgetitial section taken just below the surface, as in PI. XIII., fig.
i^b); c, Part of a vertical section, greatly enlarged.

of the typical M. petropolitana, Pand., with which it has gener-
ally been confounded by myself and others. When young it is
a concavo-convex disc ; but it usually becomes elevated and

3i8 TABULATE CORALS.

hemispherical when fully grown. The lateral margins of the
corallum are, however, very often extended and comparatively
thin, the chief elevation of the corallum being central, and there
is often a curious funnel-shaped depression at the summit of the
colony, the nature of which I do not understand. Adult coralla
reach a diameter of from one and a half to three inches, with a
height of three-quarters of an inch to an inch. The characters
of the surface are very like those of the typical M. petropolitana,
Pand., especially in the presence of low elevations or monticules,
composed of corallites which seem to be slightly larger than the
average. Thin sections show that the corallum also, as in M.
peh'opolitana, is composed of very thin -walled corallites, the
walls of which are undistinguishably united, and are not thick-
ened towards the surface ; while two distinct sets of tubes, of
different sizes, form by their intermixture the entire colony.
Tangential sections (PI. XIII., fig. 4 b) clearly exhibit both
groups of corallites, both being angular in shape, and the
small tubes being situated at all the angles left between the
larger ones. The latter are seldom completely surrounded
by small tubes, though this does sometimes occur. Very
characteristically the large tubes are arranged in stellate
groups or rosettes, consisting of four or five tubes ; and
the central point where these meet is marked by a thick-
ened rounded or quadrate body, which exhibits commonly a
median tube. Similar structures are often developed at the
points where the small corallites abut against the larger ones,
and their appearance is precisely similar to that of the
"columns" oi Dekayia, or the spines of certain of the Monti-
culiporcs as seen in transverse section. I cannot say, however,
that I have ever detected spines on the surface in this species,
though I cannot doubt that the structures to which I have just
referred are peculiarly modified corallites. Vertical sections
(PI. XIV., fig. i) show that the corallites, instead of being
reclined towards the margin of the colony, are everywhere
nearly perpendicular to the epithecal plate ; and they further
show very striking differences in the structure of the large

GENERA OF CH.ETETID^ AND MONTICULIPORIDyE. 319

and small tubes. The former are not uniformly similar in
structure. In some cases they are simply crossed by a few
remote tabulae, as is usual among the Montic2tlipo7'cE. In
other cases, and more commonly, however, they exhibit
throughout or in part of their course a very singular double
arrangement of the tabulae, the explanation of the phenomena
in question being still unknown to me. In these cases the visc-
eral chamber of the corallite may be considered as divided into
two lateral halves or compartments. In one half of the tube
the tabulae are not only remote, but are strongly convex, with
their convexities directed upwards, or towards the centre of
the visceral chamber, thus forming a series of large lenticular
vesicles, the internal margins of which unite so as to form an
apparent median septum to the tube. In the other half of the
corallite the tabulae are simply remote, complete, and horizontal,
extending from the lateral wall of the corallite on the one hand
to the inner margin of the lenticular vesicles just mentioned on
the other hand. Lastly, the smaller corallites are uniformly
provided with very numerous crowded and complete horizontal
tabulae.

The features which separate M. {Diplotrypd) Whiteavesii,
Nich., from the typical M. petropolitana, Pand., have been
alluded to in speaking of the latter, and need not be further
insisted on here. The internal structure of the corallum, and
especially the remarkable form of tabulation displayed by the
greater number of the large corallites, will serve to differen-
tiate the species from all other types which resemble it in
general shape and aspect.

I have named the species after my friend Mr Whiteaves,
the accomplished palaeontologist of the Canadian Geological
Survey.

Formation and Locality. — Abundant in the Trenton Lime-
stone of Peterboro', and of other localities in Ontario.
Specimens of a rounded form attached by a broad base to
foreign bodies occur also in the Cincinnati group of Waynes-
ville, Ohio. .

320 TABULATE CORALS.

Sub-genus Monotrypa, Nicholson, 1879.

I propose the name of Monotrypa for a few forms of Monti-
culipora which agree with those that I have called Diplotrypa
in the fact that the corallites are thin-walled throughout their
entire extent, and are so amalgamated in contiguous tubes that
their originally double structure is not recognisable. On the
other hand, they differ from Diplotrypa in the fact that the
closely-tabulate small corallites of the latter are now totally
absent, the colony consisting of subequal tubes which are uni-
formly and throughout provided with remote and complete
tabulae. The only sign of dimorphism, in fact, which can be
detected in the Q.Q)V2\\\i'ccioi Monotrypa is the constant existence
of special clusters ("monticules") of corallites, which are de-
cidedly larger than the average tubes, though quite like these
in internal structure.

There are several respects in which this section of the genus
Montictilipora must be considered as not wholly satisfactory, at
the same time that the composition of the corallum out of tubes
which are identical in internal structure, and which differ very
little in point of size, precludes our associating the forms in
question with any of those we have been previously considering.
In some points Monotrypa makes an approach to Ckcstetes
proper, but the much greater thinness of the walls of the coral-
lites, and the constant presence of clusters of large tubes, suffi-
ciently distinguish the species of the former from those of the
latter. The only two forms which I at present know as com-
bining all the features here ascribed to Monotrypa are those
which I shall describe immediately under the name of M. un-
dnlata and M. Winter i. Typical examples of the M. pulchelhy
E. and H., from the Upper Silurian of Britain, show, however,
all the general characters of Monot7'ypa (see PI. XIV., figs.
6, 6 a), except that the walls of the corallites become decidedly
thickened in approaching the surface, and the boundary-lines
between contiguous tubes are usually clearly marked. (I have

GENERA OF CHyETETID^ AND MONTICULIPORID^. 321

not yet submitted to microscopic examination the forms from
the Lower Silurian rocks of North America which have usually
been known to American palaeontologists as M. pulchella or
ChcBtetes pulchellus ; but I suspect they will prove to be distinct
from the British Upper Silurian examples, which are the true
type of the species).

Monticulipora (Monotrypa) undulata, Nich.
(PI. XIV., figs. 3-3/., and 4-4^.)

ChcBtetes undidatus, Nicholson, Geol. Mag., Dec. ii. vol. ii. p. 176, 1875.
,, undulattis, Nicholson, Rep. on the Pal. of Ontario, 1875, PP- 1O5 ZZ^
PI. IV., fig. I.

Spec. Char. — Corallum forming large lobed or laterally in-
dented masses, or occurring as smaller hemispherical or spher-
oidal masses, of from half an inch to more than an inch in
diameter. Corallites uniformly thin - walled, angular, and
prismatic in shape, sub-equal in size, varying from one-fifth or
one-sixth of a line up to a quarter of a line or rather more.
The bulk of the corallum is made up of corallites of the smaller
of the above dimensions, while the slightly larger tubes form
clusters of six or more, which appear on the surface as patches
or " monticules," which are but faintly or not at all elevated
above the general level. Tabulae horizontal, complete, remote,
equally distributed through all the tubes of the colony, and
often placed at corresponding levels in contiguous tubes, so
that the corallum breaks up into a series of concentric strata.

Obs.—T\i^ type of this species is a large and massive coral,
which occurs in the Trenton Limestone of Canada. With this
I formerly associated certain large and lobate MoiitiaUiporcB
from the Cincinnati group of Ohio and the Hudson River for-
mation of Canada, similar in form to some of those included by
Hall under the name of Chcstetcs lycoperdoji, Say (Geol. Mag.,
Dec. ii. vol. ii. p. 177). I have not yet had the opportunity of
examining these latter forms microscopically, but I imagine
that I shall find I was in error in associating these with the

X

322 TABULATE CORALS.

Trenton Limestone species. On the other hand, a minute
examination of the corals of the Hudson River group of
Canada, which have commonly been spoken of as " puff-ball
varieties of Stenopora fibrosa',' and which I used to regard (op.
jam cit. p. 176) as a mere variety oi M. petropolitana, Pand.,
has shown me that these are in reality entirely identical in
internal structure with the M. undulata of the Trenton Lime-
stone, from which they only differ in their smaller size and
hemispherical or spheroidal shape (PI. XIV,, fig. 3). I have
figured thin sections of both for comparison.

Tangential sections of both the Trenton Limestone and
Hudson River group examples of M. undulata (PL XIV., fig.
4 and fig. 3 a) show the corallites to be strikingly thin-walled,
and markedly angular, while, except for the occasional presence
of a cluster of somewhat extra-sized tubes, their dimensions are
very uniform. Here and there, of course, small corallites will
occur, but these are simply young tubes, such as would be seen
in any tangential section of a Favosites, and they do not form
part of a regular series of special corallites. That this view is
correct is shown by their very occasional occurrence, but is still
more conclusively proved by vertical sections (PI. XIV., figs.
3 b and 4 a). These show that all the corallites — those forming
the clusters as well as those composing the mass of the colony
— are precisely similar in their structure, and are not divisible
into a series with remote and one with crowded tabulae. All
alike have thin, flexuous, often closely undulated walls, and in
all alike the tabulae are delicate horizontal plates, situated at
distances of from a quarter of a line to nearly a line. In all
the specimens I have examined there is, also, an evident
periodicity of growth, tabulae being periodically developed at
corresponding levels in all the tubes, so that the entire corallum
breaks up into concentric layers.

Forinatioii and Locality. — Rare in the Trenton Limestone of
Peterboro', Ontario. Common (the " puff-ball variety ") in the
Hudson River group of Toronto, Weston, and other localities
in Ontario.

GENERA OF CH.ETETID.E AND MONTICULIPORID.E. 523

Monticulipora (Moiiotr3rpa) Winteri, Xich.
(PI. XIII., figs. 5, 5 .7 : PL XIV., figs. 2, 2 a:)

Spec. Chai'. — Corallum when young, discoid and concavo-
convex ; when aduh, hemispherical or subglobular. Young
examples may be three or four lines in diameter, and less than
two lines in greatest height ; while fully-grown specimens may
be more than an inch and a half in diameter, and more than an
inch in heis^ht. The base is free, or attached to some foreio^n
body at one point, and it is either tiat or concave, and is
covered by a concentrically-striated epithecal membrane. The
corallites radiate from the base and open upon the upper sur-
face by thin -walled polygonal calices. The surface shows
clusters of slightly extra-sized corallites, which are only occa-
sionally elevated to form low " monticules." The corallites
are all uniformly thin-walled, strictly angular or prismatic in
form, and subequal in size, averaging a quarter of a line in
diameter. In internal structure they are all alike, all being
provided with delicate, remote, complete, and horizontal
tabulae.

Obs. — Examples of this species are of common occurrence in
the Devonian Limestone of Gerolstein, and are so entirely
similar in form (PI. XIII., hgs. 5, 5 a) to the Lower Silurian
j\L pctropolitana, Pand., that a merely macroscopic examina-
tion would almost certainly have led to their being identified
with the latter form. A microscopic examination, however,
shows that their structure is that oi Monotrypa, and not diat
of Diplotrypa, all the tubes alike being essentially similar in
their internal characters. Tangential sections (PI. XI\'.. tig. 2)
show that the tubes are essentially uniform in size, a few
slightly larger ones forming scattered clusters, while such in-
tercalated small ones as are present are obviously merely young
corallites. All the tubes also are bounded by very delicate
walls, and are regular, angular, and prismatic. \'ertical sec-
tions (^Pl. XI\'.. hg. 2 a) show a complete identity in structure

324 TABULATE CORALS.

in all the corallites, the tabulae being complete and remote,
and sometimes placed at corresponding levels in many of the
tubes.

From M. tmdtdata the present species is distinguished by
its concavo-convex or regularly hemispherical form, by the
more rapid intercalation of the new tubes, and by the greater
abundance of the tabulae, while it never attains the dimensions
or assumes the lobate habit of the former.

I have named the species in honour of Herr Winter of
Gerolstein, from whom I received much friendly assistance
while collecting in the Eifel.

Formation and Locality. — Not uncommon in the Devonian
of Gees, near Gerolstein, Eifel.

Genus Prasopora, Nich. and R. Eth., jun., 1877.
(Ann. Nat. Hist., ser. 4, vol. xx. p. 38.)

Gen. Char. — Corallum compound, concavo-convex or hemi-
spheric in form, composed of numerous prismatic corallites
radiating from a wrinkled basal epitheca. Corallites of two
kinds, large and small, ^ regularly and uniformly intermingled
throughout the entire colony. No "monticules" or clusters of
large tubes. All the corallites thin-walled, and prismatic or
angular in shape ; the large tubes furnished with an exterior
zone of vesicular tabulae surrounding a vacant central tube,
which may be crossed by an occasional tabula. Small corallites
arranged in a zone (rarely or never quite complete) round the
large tubes, and crossed by numerous close-set, complete, and
horizontal tabulae.

^ In our original description of Prasopora {loc. df.), as well as in our " Mono-
graph of the Silurian Fossils of Girvan," Fasc. I., p. 44, Mr Etheridge and I em-
ployed the term of "coenenchymal tubuli " for the small corallites. We did so,
however, simply in conformity with the nomenclature employed by Milne-Edwards
and Haime, and we expressed the opinion that the small tubes are " really of the
nature of rudimentary corallites, which contained in the living state a series of
small and specially modified zooids."

GENERA OF CH^TETIDM AND AIONTICULIPORID^.

125

Obs. — This singular genus was founded by Mr R. Etheridge,
jun., and myself for the reception of a small coral from the
Lower Silurian deposits of GIrvan, Ayrshire, to which we gave

Fig. 43. — Prasopora Grayer, Nich. and Eth., jun. A, Under side of a small example, showing
the epitheca, of the natural size. B, Side view of a larger specimen, of the natural size.
C, Tangential section enlarged twenty times. D, Vertical section similarly enlarged :
a, One of the large corallites ; b, One of the small corallites. The dark shading in the
microscopic sections indicates the presence of the matrix.

the name of Pj'asopoj'a GraycE. The characters of the genus
and species have been so fully treated of by us {loc. cit. and
Monograph of the Sil. Foss. of Girvan, Fasc. I., pp. 44-48),
that it is unnecessary for me to do more than briefly allude to
the most striking features of the structure of the corallum.

In general form and size the corallum of Prasopoi^a GraycB
(fig. 43, A and b) precisely resembles that of moderately young
examples of Monticulipora petropolitana, Pand., with which a
merely external examination would almost certainly lead the
observer to place it. This, therefore, affords another example
of the uselessness of attempting to decide the true structure
and position of any Monticuliporoid by an appeal to its form
and general aspect. The corallum is conspicuously and very
remarkably dimorphic, the large and small corallites being uni-
formerly distributed throughout the entire colony, and being
singularly different in internal structure. The structure of the
large corallites is most easily recognised in longitudinal sections
(fig. 43, D, a), in which each Is seen to possess a central tube,
occupying the axis of the visceral chamber, and entirely sur-

326 TABULATE CORALS.

rounded by a circumferential zone of peculiarly modified tabulae.
The central tube may be open throughout, but it is usually
intersected, at remote intervals, by delicate horizontal tabulae.
Surrounding the central tube on all sides, and forming its walls,
is a zone of tabulae, which spring from the wall of the corallite,
and are then bent downwards so as to become parallel to the
long axis of the corallite, finally joining the next tabulae below.
There is thus formed a series of large circumferential vesicles,
the convexities of which are directed upwards and towards the
centre of the corallite. When the section does not pass accu-
rately through the median plane of the corallites (as it very
commonly does not), then it comes to intersect the exterior
tabulate zone, and the cut edges of the vesicular tabulae appear
as transverse lines and simulate ordinary tabulae ; so that in
most sections parts of the tubes exhibit one set of appearances,
and parts show the other. When examined in tangential sec-
tions (fig. 43, c, a), the large corallites are seen to be hexa-
gonal, prismatic, or subpolygonal, and in the centre of each is a
rounded or oval opening representing the transverse section of
the central tube of the corallite. This opening is surrounded
by a variable number of curved lines, which are tangents to
the margin of the median aperture, or are concentric with it, or
intersect one another. These lines are the cut edgfes of the
vesicular tabulae which form the exterior zone of the corallite ;
and when thus exhibited they closely resemble the similar
lines produced by the transverse section of the central tube
and the infundibuliform tabulae in Syringopora.

The smaller corallites of the colony are seen in tangential
sections (fig. 43, c) to be wedged in among the large tubes,
round which they are disposed in a single row. The circle
thus formed is, however, rarely or never quite complete, and
each of the large tubes usually comes into contact at different
points with one, two, three, or even four of its neighbours.
The small corallites are angular in shape, mostly oblong or
trapezoidal, and are very variable in size, being always very
much inferior in size to the larger corallites. Vertical sec-

GENERA OF CH^TETID^ AND MONTICULIPORIDyE. 327

tions (fig. 43, D, b) show also that their Internal structure dif-
fers entirely from that of the large tubes, and resembles that
of the smaller corallites among the Monticuliporidce generally,
the visceral chamber being simply crossed by crowded, com-
plete, and horizontal tabulae.

As regards its affinities, there cannot be any doubt but that
Prasopo7^a is a genuine Monticuliporoid, and that it is most
nearly allied to that section of Monticulipora which I have
named Diplotrypa, and of which M. petropolitana, Pander, is
the type. There is, indeed, a distant approach to the peculiar
structure of the large corallites of P^'asopora in the large vesi-
cular tabulae which are commonly found on one side of the
visceral chamber in the corresponding corallites of M. {Diplo-
trypa) Whiteavesii, Nich. (see PI. XIV., fig. i). The existence,
however, of a complete peripheral zone of vesicular tabulae,
enclosing a central tube, is a feature of an entirely unique
nature, and fully entitles Prasopora to take rank as a distinct
genus.

The only known species of Prasopora occurs commonly in
the *' Craighead Limestone " (Lower Silurian) of Craighead,
near Girvan, Ayrshire, whence it was collected by Mrs Robert
Gray.

Gemis Dania, Milne-Edwards and Haime, 1849.
(Comptes Rend., t. xxix. p. 261.)

The genus Dania was proposed by Milne- Edwards and
Haime for the reception of a single species {D. Huro7iica)
from the Upper Silurian of Drummond Island, Lake Huron ;
and they give the following as the characters of the genus (Pol.
Foss. des Terr. Pal., p. 275) : —

" Corallum massive, composed of prismatic corallites, which
are intimately united by their well-developed walls. Tabulae
completely horizontal, and continued across contiguous cor-
rallites in such a manner as to give rise to continuous lamellae,

328 TABULATE CORALS.

which divide the entire mass into a series of superposed strata.
Cahces subpolygonal. No traces of septa."

Not having seen the original specimens upon which Milne-
Edwards and Haime founded the genus Dania, I am unable to
give any final opinion as to the validity or the reverse of the
genus. It is clear from their description, and still more from
their figures, that Dania Hit,ro7iica is a Chsetetoid or Monti-
culiporoid Coral ; and it is also clear that the single character
emphasised by Milne-Edwards and Haime — namely, the pres-
ence of tabulae placed at corresponding levels in contiguous
tubes — is not of itself sufficient for greneric characterisation.
This is amply proved by the fact that a like periodic production
of tabulae, giving rise to a similar division of the corallum into
superimposed concentric layers, occurs in such different forms
as Stenopora criiiita, Lonsd., from the Carboniferous, and
Monticulipora undulata, Nich., from the Lower Silurian, as
well as in the familiar C/icstetes radians, Fischer, of the Car-
boniferous. Professor Martin Duncan (Third Rep. on the
Brit. Foss. Cor.; Rep. Brit. Ass. 1871, p. 128) is of opinion
that Dania, E. and H., is inseparable from Chcstetes, Fischer,
and in this view he is very probably correct, though I do not
know what positive evidence exists upon the point.

The only other coral that I am acquainted with as having
been referred to the genus Dania is the Thecia multiseptosa,
A. Romer (Beitrage III., p. 2, PI. 2, f. i, 1855), from the
Lower Devonian of Germany. This form was doubtfully
referred by Romer to Thecia, but Giebel assigned it to Dania
(Sil. Fauna Unterharz, p. 59, PI. 6, f. 3 and 4, 1858), and this
view is also taken by Kayser (Fauna d. Alt. Devon. Ablager.
des Harzes, p. 223, 1878). Judging from the figures given by
Kayser, the close-set tabulae are certainly placed at correspond-
ing levels in contiguous corallites ; but there is nothing definite
brought forward except this character to justify its being placed
in Dania. It appears to be either a member of the genus Chcs-
tetes or Favosites.

GENERA OF CH^TETID^E AND MONTI CULIPORID.E. 329

Genus Beaumontia, Milne-Edwards and Haime, 185 1.
(Pol. Foss. des Terr. Pal., p. 276.)

The genus Beaumontia was founded by Milne-Edwards and
Haime {loc. cit. supra) for the reception of certain Carbonifer-
ous and Devonian Corals, to which they ascribed the following
common characters : —

" Corallum generally massive ; the corallites usually prismatic
and amalgamated by their walls, but occasionally partially free.
The walls thin, provided with an epitheca. The tabulae vesi-
cular, or, at any rate, irregular, occasionally exhibiting upon
their surface septal striae."

The distinguished French observers just quoted regard
Beaumontia as corresponding in the series of the ChcetetidcB
to Michelinia^ De Kon., in the series of the Favositidcs ; and
they assert that the walls of the corallites are destitute of
mural pores. If this last character be certainly established,
then the genus may be regarded as undoubtedly distinct ; but
the general resemblance of the corallum in the species of Beau-
montia to Michelinia would rather lead one to suspect that
mural pores may really exist, and that the genus is truly refer-
able to the Favositidcs. Not, however, having had any oppor-
tunity of examining specimens of Beaumontia, I am necessarily
unable to pronounce any opinion on this point. I may add,
however, that Dr Lindstrom (Ann. Nat. Hist, sen 4, vol.
xvill. p. 16) refers Beattmontia to the Favositidcs ; while Prof.
Martin Duncan (Third Rep. on the Brit. Foss. Corals ; Rep.
Brit. Ass., 1 87 1, p. 135) regards the genus as being properly
referable to the Halysitidcs. I am not aware, however, of any
published evidence which would positively decide between
these opposing views.

33°

CHAPTER XIV.

LABECHID/E.

The extraordinary Upper Silurian genus Labechia, E. and H.,
alone constitutes this group, and its characters are so abnormal
that we must in the meanwhile regard it as the type of a special
family, to which the name of LabechidcB may be applied. As
we have, however, to deal in this family with only a single
genus, comprising only a single species, the characters of the
group will be sufficiently elucidated by a consideration of the
structure of the genus. As a definition of the group it will be
sufficient to say that it comprises calcareous corals (?), composed
of laminar or submassive expansions, which are fixed by the
centre of the base, and have the rest of the lower surface
covered with an epitheca ; the skeleton being composed of a
series of calcareous, primitively tubular, but finally more or
less completely solid columns, which project above the surface
as so many rounded or elongated imperforate tubercles ; the
spaces between the columns filled with a cellular tissue of len-
ticular vesicles, and the intervals between the surface-tubercles
covered by a continuous and imperforate calcareous membrane.

Genus Labechia, Edwards and Haime, 1851.
(Pol. Foss. des Terr. Pal., p. 279.)

Gen. Char. — Corallum usually having the form of a larger
or smaller laminar expansion, which is attached by a portion of
its base to some foreign object, the remainder of the lower

LABECHID^.

331

surface being covered by a concentrically - striated epitheca.
Upper surface covered with rounded or elongated, sometimes
partially confluent, tubercles, which are quite solid, and are
separated by an imperforate calcareous membrane. In internal
structure, the corallum consists of a great number of cylindrical
calcareous columns, which are directed vertically upwards from
the basal epitheca, and the upper ends of which constitute the
surface-tubercles above mentioned. The columns sometimes
appear to be solid throughout ; sometimes they exhibit more or
less distinct traces of a minute central tube ; so far as certainly
observed, they are apparently solid at their upper ends. The
interspaces between the columns are occupied by a series of
lenticular vesicles, the convexities of which are directed up-
wards, and the uppermost layer of which gives rise to the
seemingly imperforate membrane which forms the whole of the
upper surface between the tubercles.

Obs. — The genus Labechia was originally founded by Milne-
Edwards and Haime for the reception of the singular L. con-

FifT. 44. — Labechia conferta, E. and H. a, A small specimen from the Upper Silurian ot
Gotland, of the natural size. B, Portion of the upper surface of the same enlarged, show-
ing the surface-tubercles, c, Part of a vertical section of the same, enlarged : a, the cal-
careous columns represented as opaque ; b, the lenticular vesicles, filled with calcite.

ferta of the Upper Silurian rocks, which is still the only de-
scribed species of the genus. As to the structure and affinities
of Labechia, the French authors regarded it as referable to the
ChcetetincE, and they describe it as having a corallum with con-
fluent and not distinct calices, the " visceral chambers filled up

332 TABULATE CORALS.

with complete, horizontal, closely-set tabulae, and presenting
quite rudimentary septa ; " while they regard the surface-tuber-
cles as processes springing from the edge of the walls (Brit.
Foss. Cor., p. 269). Professor Martin Duncan (Third Rep. on
Brit. Foss. Corals; Rep. Brit. Ass., 1871, p. 128) appears to
take nearly the same view of the affinities of Labechia as that
put forward by Edwards and Haime ; but he considers that it
should be regarded as simply a sub-genus of Monticulipora.
No evidence, however, in support of this view is actually ad-
duced, so that I can merely mention the opinion held by this
distinguished authority. On the other hand, Dr Lindstrom
(Ann. Nat. Hist., sen 4, vol. xviii. p. 4) correctly pointed out
that there is not in Labechia " the least trace of any wall cir-
cumscribing any calicle, or of any septa ; " and he adopts the
view — which will be more fully noticed at a later period — that
the genus is not Actinozoan at all, but truly Hydrozoan in its
affinities. Lastly, the internal structure of Labechia, as eluci-
dated by means of microscopic sections, was, so far as I am
aware, first pointed out by Dr Murie and myself in a memoir
upon the Stromatoporoids (Journ. Linn. Soc, vol. xiv. p. 232).
The skeleton of Labechia is calcareous, and entirely resem-
bles that of many of the composite Corals in its general y^r/;^
(fig. 44, a), constituting, as it does, a laminar expansion, attached
by a basal peduncle, and having its lower surface covered by
a concentrically -striated epitheca. On looking at the upper
surface of the colony (fig. 44, b, and PI. XV., fig. 4 a), the
most striking feature is the apparent total absence, even in the
best-preserved examples, of any of the apertures or " calices "
that one would expect to find in any normal compound corallum.
On the contrary, the whole of the upper surface is covered
by a thin imperforate calcareous membrane, which is studded
closely and throughout with blunt, elevated, conical, or elon-
gated solid tubercles, which sometimes run into one another
and give rise to vermicular ridges. No other features than the
above can be recognised by a mere examination of the exterior
of the perfect corallum. As regards the internal structure,

LABECHIDyE. 333

thin vertical sections (fig. 44, c) at once show that the surface-
tubercles are the summits of a series of vertical columns which
spring from the epitheca below, and are separated by intervals,
which are in general equal to their own width. As viewed in
sections of this kind, the columns appear to be composed of
homogeneous granular carbonate of lime, which often shows
no differentiation into parts. In many cases, however, a central
darker or lighter portion may be distinguished from the mar-
gins. In tangential sections (PI. XV., fig. 4), on the other
hand, the transversely-divided columns appear as so many oval
or rounded bodies, separated by small intervals, and their real
structure can now be more satisfactorily studied than in long
sections. It was originally believed by Dr Murie and myself
that the columns were absolutely and throughout solid and
homogeneous, and in many instances they certainly appear
to be so, while their upper ends seem to be generally solid.
In the examination, however, of a series of thin tangential
sections, I find that in many cases the columns really show a
distinct differentiation of their tissues. I find, namely, that
the columns exhibit in cross-section a more or less distinct
composition out of delicate concentric lamellae (PI. XV., fig. 4),
the outermost of which are occasionally denser than the others,
and form a distinct marginal line ; while there exists centrally
a larger or smaller axial area, which may be either darker or
lighter than the rest of the column, and may be surrounded by
a definite dark marginal ring. This central area appears really
to be a central tube, which is sometimes persistent, but in other
cases becomes filled up, in process of growth, with dense scler-
enchyma. There is thus reason to believe that the columns
of Labechia are primitively tubular, but that the median tube is
finally largely or entirely obliterated ; while I have at present
no positive evidence which would go to show that the axial
canal is ever absolutely continued to the summit of the column,
so as to open on the surface by a distinct aperture. As a rule,
the surface-tubercles appear to be absolutely solid and imper-
forate ; but I have been occasionally able to detect a minute

334 TABULATE CORALS.

central depression at their apices, which would appear to show
that the central tubes of the columns are really sometimes open
above. In specimens which have been slightly weathered,
also, one may often recognise under the microscope the exist-
ence of an unmistakable central tube in the columns, though I
certainly cannot affirm that I have ever been able to detect
any openings to which the name of " calices" could be applied.

The interspaces between the columns in the skeleton of
Labechia are entirely filled (fig. 44, c) with a cellular tissue
formed by curved calcareous lamellae, which have their convex-
ities directed upwards, and give rise to a series of lenticular
vesicles which extend from the epitheca below to the surface
above, and appear to be bounded superiorly and superficially
by a delicate calcareous membrane. In tangential sections (PI.
XV., fig. 4) the cut edges of the curved lamellae which form
the lenticular vesicles appear as irregular curved lines extend-
ing between the transversely-divided columns, and subdividing
the intervening space into irregular compartments. Both in
vertical and in tangential sections, the appearances presented
by the interstitial tissue present some curious resemblances to
those exhibited by species of Fisttilipora (such as I^. minor,
M'Coy, and F. incrassata, Nich.), in which the tabulae of the
small corallites coalesce and give rise to vesicular tissue.

Having now briefly discussed the intimate structure of La-
bechia, it remains to make a few remarks upon its possible affin-
ities and systematic position. The most recent and most widely
adopted theory upon this subject is that put forward by Dr
Lindstrom (Ann. Nat. Hist., ser. 4, vol. xviii. p. 4). Accord-
ing to this acute observer, the skeleton oi Labechia in its earliest
stages of growth consists of "a very thin circular disc, with
concentric lines of growth beneath, and having the superior
surface studded with blunt spines, which radiate from the cen-
tre, and also coalesce and form continuous ridges. In this state
it reminds one of nothing more than the sclerobasis of the
Hydrozoan genus LLydractinia ; and the only difference seems
to be that Labechia is entirely calcareous, whilst Hydractinia

LABECHID.E. 335

is corneous. During the course of growth the primitive disc
of Labechia is increased in thickness by the addition of suc-
cessive thin strata, which closely conform to the subjacent
fundamental crust, being elevated where the spines are situ-
ated. As these successive layers leave a small space between
them, and are in themselves very thin, they give rise to a false
appearance of tabulae."

Apart from the fact that our present knowledge of the minute
structure of Labechia will not allow us to accept the above
account of the development of the skeleton as entirely correct,
there are certain general considerations which preclude an
unhesitating acceptance of the Hydractinian affinities of the
genus. The most important of these considerations are, in
the first place, that the skeleton of Hydractinia is encrusting,
whereas that of Labechia is entirely like that of many corals,
and is provided with a basal " epitheca ; " while, secondly,
the columns of Labechia are not certainly known to be per-
forated at their summits, and there is at present no evidence of
the existence of any superficial cells or openings which may be
supposed to have given exit to the zooids.

As we have previously seen, the genus Labechia was referred
by Milne-Edwards and Haime to the ChcetetincB, and has been
more recently regarded by Professor Martin Duncan as a
sub-genus of Montictdipoj'a. It is, indeed, quite clear that if
Labechia be a coral at all, then it will find its nearest ally in
the MonticuliporidcB, and especially in Fistulipora, M'Coy.
From this point of view, it is worth while to glance for a
moment at the resemblances presented by Labechia conferta,
E. and H., and Fistulip07^a incrassata, Nich., as regards their
internal structure. Thus, if we compare the vertical section
of these two types (see fig. 44 c, and PI. XV., 3 b) we see
that in both the basis or general tissue of the skeleton is made
up of a series of lenticular vesicles, traversed at regular inter-
vals by the vertical columns in Labechia, and by the tabulate
tubes of the large corallites in the Fishdipora. Similarly in
tangential sections (PL XV., 4, and PI. XV,, fig. 3 a), we have

336 TABULATE CORALS.

the transversely -divided columns of Labechia connected by
irregular lines representing the cut edges of the lenticular
vesicles ; while in the Fistulipoj^a we have the cut sections of
the large tubes united by lines, which are also the cut edges of
the lenticular vesicles, but which in this case are regular in form
and mark off the boundaries of the small corallites. When we
consider the above resemblances, we are very much tempted to
conclude that LabecJiia is a coral similar to Fistulipor-a (or to
Propora in the series of the HelioporidcB), but having the vis-
ceral chambers of the large corallites largely or totally obliter-
ated in process of growth. The conversion of some of the
corallites into spines or columns is a phenomenon which we
have seen to occur in some of the MontictdiporidcE {e.g., in
Dekayia), and would not, therefore, be an absolutely unex-
ampled occurrence. If, however, we were to accept this view,
we should have to believe that in Labechia it is the large coral-
lites of the colony which have their cavities obliterated, and thus
become columnar, no such thing having been noticed among
other types of corals. Moreover, in the case of corals like
Fistulipora and Propora, we know exactly what is the nature
of the interstitial vesicular tissue. We know, namely, that this
tissue is formed simply by the coalescence and anastomosis
of the tabulse of a series of small interstitial corallites, the
walls of which are imperfectly developed ; and we know that
the calices of these small corallites can often be detected on
the surface in the intervals between the large tubes. (In this
connection it should be remembered that the mouths of the
small corallites of FisHilipora are commonly closed by a cal-
careous membrane, so that only the calices of the large tubes
can be recognised at the surface). On the other hand, there
is no distinct evidence that the vesicular tissue of Labechia
is formed in a manner similar to the above, by the conflu-
ence of the tabulse of a series of small corallites ; and, upon
any view, we are confronted with the inexplicable circum-
stance that no apertures or " calices " have ever been cer-
tainly detected on the surface of the skeleton. Till open-

LABECHID.E. 337

iiigs of some kind have been detected, or till some sort of
explanation can be given as to their absence, it appears
impossible to come to any definite conclusion as to the affi-
nities and zoological position of Labechia, since surface-open-
ings are as essential to our conception of a coralligenous
Hydrozoon as to that of an Actinozoon. At the same time,
the resemblances which I have pointed out between Lahcchia
and certain of the Fistiiliporce should not be lost sight of, and,
pending more complete investigations, I am disposed at pres-
ent to consider that we have in these points of likeness the
real clue to the true relationships of the former.

As to its geological range, the only described species of
Labcchia is the L. conferta, E. and H., of the Upper Silu-
rian, which is a familiar fossil in the Wenlock Limestone
of Britain and the Continent of Europe. I have never seen
any example of the genus in the corresponding formation
(Niagara Limestone) in North America ; but I possess a
specimen of Labcchia from the Cincinnati group of Ohio,
thus extending the range of the genus to the Lower Silu-
rian ; though I have not yet determined whether or not
this ancient form is specifically identical with the L. confcrta
of Europe.

INDEX.

The names of genera and species which are actually described in this work are distinguished by
means of an asterisk. Names of genera and species that are regarded as synonyms are
printed in italics.

Acropora, Oken, 105.

* Alveolites, Lam., 117.
Alveolites celleporatiis, D'Orb., 82.
Alveolites cervicornis, De Blainv., 82.
Alveolites escharoides, Lam., 126.
Alveolites Fischeri, Bill., 91.
Alveolites Fischeri, Nich., 91.
Alveolites frondosa, Nich., 94.
Alveolites Grayi, Edw. and H., 128.

* Alveolites Labechei, Edw. and H., 128.
Alveolites reticulata, De Blainv., 82.
Alveolites spongites, D'Orb., 82.

* Alveolites suborbicularis, Lam., 126.

* Arasopora, Nich. and Eth., jun., 165.
Arasopora australis, Nich. and Eth.,

jun., 166, 167.
Astrcea stylophora, Eaton, 143.
Astroceriuni, Hall, 37, 40, 54.

* Aulopora, 208, 219, 220, 221.
Aulopora cornuta, Bill., 117.
Aulopora repens, Edw. and H., 220.
Aulopora spicata, Goldf., 112.
Aulopora uinbellifera, Bill., 116.
AuloporidcC, Nich., 20, 219.
Axopora, Edw. and H., 14.

Battersbyia, Edw. and H., 242.

* Beaumontia, Edw. and H., 329.

* Billingsia, De Kon., 185.

Calatiiopora, Goldf., 37, 42.
Calaniopora basaltica, Goldf. (pars),
^6.

Calamopora Gothlandica, Goldf., 46.
Calamopora polymorpha, Goldf., 84.
Calaniopora polymorpJia, van ravioso-

divaricata, Goldf., 82.
Calamopora polymorpha, var. gracilis,

Goldf., 85.
Calamopora spongites, var. ramosa,

Goldf., 82.
Calamopora spongites, var. tuberosa,

Goldf., 126.
Calapoecia, Bill., 162.
Calapoecia Anticostiensis, Bill., 163.
Calapoecia Canadensis, Bill., 163.
Calapoecia Huronensis, Bill., 163.
Callopora, Hall, 304.
Callopora incrassata, Nich., 308.

* Cannapora, Hall, 204.
Ceramopora, supposed relations of to

Monticulipora, 282, 286.

* Chastetes, Fischer, 260.
Chcetetes attritus, Nich., 298.
Chcetetes {f) Bowerbanki, Edw. and H.,

72.
Chcetetes Dalei, Nich., 296.
Chcetetes mainmtilatus, Edw. and H.,

294.
Chcetetes petropolitan?/s, Nich., 316.

* Chastetes radians, Fischer, 266.
Chcetetes ramosus, Edw. and H., 296.
ChcEtetes ramosus^ Nich., 296.
Chcetetes undulaties, Nich., 321.

* Chastetidffi, 27, 253.

* Chonostegites, Edw. and H., 152.

54°

INDEX.

* Chonostegites Clappi, Edw. and H.,

153, 154, 155-
Cladochonus, 217, 222, 223.
Cladochonus crassus, M'Coy, 222, 223,

224.
Cladochonus Michelini, Edw. and H.,

220, 222, 223.
Cladopora, Hall, 79, 80.
Cladopora Canadensis, Rom., 94.
Cladopora Fischer i., Rom., 91.

* Coenites, Eichw., 130.

* Coenites juniperinus, Eichw., 134.

* Coenites linearis, Edw. and H., 135.

* Columnaria, Goldf., 191.

* Columnaria alveolata, Goldf., 195.
Colinnnaria alveolata., Hall, 200.
Colinniiaria alveolata, Bill., 200.
Columnaria alveolata, Nich., 200.
Columnaria alveolata, Rom., 200.

* Columnaria calicina, Nich., 197.
Columnaria Goldf ussi, Nich., 184.
Columnaria Gothlandica, Edw. and

H., 195.

* Columnaria (?) Halli, Nich., 200.
[Columnaria Hertzeri, Rom., 197.

Columnaria multiradiata, Castelnau,

195.
Columnaria rigida. Bill., 196.
Coluvinai'ia stellata, Rom., 195.
Columnariadce, Nich., 17, 18, 186.
■* Columnopora, Nich., 159.

* Columnopora cribriformis, Nich., 164.

* Constellaria, Dana, 292, 300.

* Constellaria antheloidea, Hall, 301.
Cyathophora lowensis, Dale Owen, 97.

* Dania, Edw. and H., 327.

* Dekayia, Edw. and H., 291, 297.

* Dekayia attrita, Nich., 298.
Dendropora, Michelin, 102, 103, 105,

106.
Dendropora explicita, Miclielin, 105,

106.
Dendropoi-a ornata, Rom., 106.
Dendropora elegantula, Rom., 108.

* Diplotrypa, Nich., 292, 312.

Eminonsia, Edw. and H., 37, 41, 68.
Emnionsia hemispherica, Etlw. and
H., 67.

Favistclla, Hall, 191.
Favistella, Dana, 191.
Favistclla calicina, Nich., 197.

Favistella stellata, Hall, 195.

* Fav'osites, Lam., 37.
Favosites alveolar is, Hall, 67.
Favosites basaltica, Goldf., 52, 56, 57,

62, 63.
Favosites Billingsii, Rom., 46, 55.

* Favosites Bowerbanki, Edw. and H.,

sp., 72.
Favosites (Fistulipora) Canadensis,

Bill., 44.
Favosites cervicortiis, Edw. and H., 82.

* Favosites clausa, Rom., 75.
Favosites clausa, Lindstr., 112, 113.
Favosites cristata, Edw. and H., 87.
Favosites cronigera, D'Orb., 82.
Favosites dubia, De Blainv., 84.
Favosites dubia, Nich., 82.
Favosites Eminonsii, Rom., 67, 68.
Favosites favosa, Goldf., 46, 53, 54.

* Favosites Forbesi, Edw. and H., 56.
Favosites Forbesi, var. discoiuea,

Roemer, 58, 152.

* Favosites Forbesi, var. Eifelensis,

Nich., 61.

* Favosites Forbesi, var. tuberosus,

Rom., 62.

* Favosites Forbesi, var. Waldronensis,

Nich., 60.
Favosites Goldfussi, Edw. and H., 46,

52, 54-

* Favosites Gothlandica, Lam., 46.

* Favosites hemispherica, Yand. anil

Shum., 67.
Favosites lir/iitaris, Rom., 82, 85.
Favosites Lonsdalei, D'Orb., 87.
Favosites Lonsdalei, Lindstr., 87.
Favosites Niagarensis, Hall, 46, 55.
Favosites petropolitanus, Band., 313.
Favosites placenta, Rom., 44.
Favosites poly morpha, Bill., 82.
Favosites polymorpha, Lonsd., 87.
Favosites poly/norpJia, Goldf., 84.
Favosites reticulata, Edw. and H., 82,

83, 85.
Favosites reticulata, Nich., 82.
Favosites spongites, Lonsd., 72, 128.
Favosites spongites, Phill., 126.
Favosites Troosti, Edw. and H., 51.
Favosites tuberosus, Rom., 57, 62.
Favosites turbinata. Bill., 38, 39, 68,

69.
Favosites Winchelli, Rom., 46, 55.
Favositidce, 16, 17, 30-36.
Favositipora, Sav. Kent, 34. 35, 36, 45.

INDEX.

34>

* Ustulipora, M'Coy, 292, 304.

* Fistulipora minor, M'Coy, 306.

* Fistulipora incrassata, Nich., 30S.

* Fistulipora proporoides, Nich., 310.

* Fletcheria, 203, 206.
Fletcheria clausa, Lindstrom, 113.

Haimeophyllum, Bill., 152.
Haimeophyllum ordmatuni, Bill., 153,
154, 155-

* Halysites, Fischer, 226.

Halysites agglomerata, Hall, 22S, 229.
Halysites catenularia, Linn., 228, 229.
Halysites escharoides, Lam., 227, 228,

229, 230.
Halysitidje, 21, 22, 226.
Harmoditcs, Fischer, 207, 211.

* Heliolites, Dana, 243.
Heliolites favosHs, vSalt., 190.
Heliopora, De Blainv., 7, 25, 26.
Helioporidce, 25, 241.
Heteropora, 256.

* Heterotrypa, Nich., 291, 293.
Honghtoiiia, Rom., 159, 161.
Houghtonia Huronica, Rom., 164, 165.
Hydrocorallinte, 8, 13, 14.

Koninckia, Edw. and H., 9, 34,35,36,45.

* Labechia, Edw. and H., 330.

* Labechia conferta, Edw. and H., 331.

* Labechidas, 29, 330.

* Laceripora, Eichw., j8o.
Laceripora cribrosa, Eichw., 181.
Limcvia Steininger, 130.
Lijuaria clathrata, Lonsd., 134.
Limaria raiiiulosa, Hall, 134.

* Lyellia, Edw. and H., 249.
*Lyopora, Nich. and Eth., jun., 1S7.
*Lyopora favosa, M'Coy, sp., 190.

Madreporitcs cri status, Blum., 87.

* Michelinia, De Kon., 139.
Michelinia Clappi, Rom., 155.
Michelinia cylindrica, Edw. and H.,

154. 157-
Michelinia intermittens, Bill., 153, 154,

155-
Michelinia trochiscus, Rom., 143.
Millepora, Lam., 2, 3, 5, 6, 7, 8, 9, 11,

13. H-
Milleporidas, 12-14.

* Monilopora, Nich. and Eth., jun., 223.
Monilopora crassa, M 'Coy, sp., 223, 224.

* Monotrypa, Ni

* Monticulipora,

* Monticulipora

lata, D'Orb

* Monticulipora

tana, Pand.,

* Monticulipora

D'Orb., 296.

* Monticulipora

Nich., 321.

* Monticulipora

avesii, Nich

* Monticulipora

Nich., 323.
Monticuliporid

ch., 293, 320.
D'Orb., 269.
(Heterotrypa) mammu-
, 294.

(Diplotrypa) petropoli-
313-
(Heterotrypa) ramosa,

(Monotrypa) undulata,

(Diplotrypa) White-
., 316.
(Monotrypa) Winteri,

ae, 28, 255, 269.

Nebulipora, M'Coy, 269.

* Nodulipora, Lindstr., 186.

* Nyctopora, Nich., 182.
*Nyctopora Billingsi, Nich., 184.

Orbipofa, Eichw., 269.
Orbitulites, Eichw., 269.

* Pachypora, Lindstr., jj.

* Pachypora cervicornis, De Blainv., sp.,

82.

* Pachypora cristata, Blum., sp., 87.

* Pachypora Fischeri, Bill., sp., 91.

* Pachypora frondosa, Nich., 94.

* Pachypora lamellicornis, Lindstr., 80,

81.
PalcEopora {?) favosa, M'Coy, 190.

* Pinacopora, Nich. and Eth., jun., 250.

* Plasmopora, Edw. and H., 245.

* Pleurodictyum, Goldf., 142.
Pleurodictyiini Ainericaman, Roemei",

143, 144-
Pleurodictyum problematicum, Goldf.,
142, 144, 145, 146.

* Pleurodictyum stylophorum, Eaton,

sp., 143.
Pocillopora, Lam., 2, 3, 4, 9, 14, 15, 16.
Pocilloporidoe, 14-16.
Porosphasra, Steinm., 14.

* Prasopora, Nich. and Eth., jun., 324.
Prasopora Grayae, Nich. and Eth., jun.,

325-

* Propora, Edw. and H., 247.
Pyrgia, Edw. and H., 219, 222.
Pyrgia Michelini, Edw. and H., 222.

Quenstedtia, Rom., 114.
Qucnstedtia umbcllifera, Rom., 116.

342

INDEX,

Rhabdopora, Echv. and H., 102, 105, 106.

* Roemeria, Edw. and H., 177.
Roemeria infundibulifera, Goldf., 177.

* Romingeria, Nich., 114.

* Romingeria umbellifera, Bill., sp., 116.

Seriatopora, Lam., 15, 16, 104, 105.

Seriatoporidse, 16.

Stellipora, Hall, 300.

Stellipora antlieloidca. Hall, 301.

* Stenopora, Lonsd., 168.
Stenopom, M'Coy, 269.

Stenopora Jackii, Nich. and Eth., jun.,

173-
Stenopora ovata, Lonsd., 172, 174.
Stenopora Tasmaniensis, Lonsd., 281.

* Striatopora, Hall, 97.

* Striatopora Linneana, Bill., 100.

* Syringolites, Hinde, 178.
Syringolites Huronensis, Hinde, 179.

* Syringopora, Goldf., 207.

* Syringopora geniculata, Phill., 217.

* Syringopora reticulata, Goldf., 215.
Syringoporidaa, 18, 19, 203.

Tabulae, nature of, 9, 11.

Tabulata, characters of, i ; history of,

2-9 ; groups of, 12-29.
Tetradiidai, 23, 231.
*Tetradium, Dana, 231.
Tetradium minus, Saff., 232, 233.

* Thecia, Edw. and H., 236.

* Thecia Swindernana, Goldf., 235, 237.
Thecidce, 24, 235, 236.
Thecostegites, Edw. and H., 203, 205.

* Trachypora, Edw. and H., 102.

* Trachypora Davidsoni, Edw. and H.,

102, 103, 104, 1 10.

* Trachypora elegantula, Bill., loS.

* Trachypora ornata, Rom., 106, 108.
Tubuliclidia, Lonsd., 168.

* Vermipora, Hall, 1 1 1.

* Vermipora clausa, Lindstr., sp., 113.

Zoantharia Tabulata {see Tabulata).
Zoantharia Tubulosa, 20, 219.

THE END.

PRINTED BY WI/J.IAM BLACKWOOD AND SONS.

PLATE I.

Fig. T. Transverse section of a typical example o{ Fai'o sites Gothlandica, Lam.,
from the Wenlock Limestone of Gotland, showing the regular, polygonal,
thin-walled corallites, enlarged five times.

Fig. I <7. A vertical section of the same, similarly enlarged. A mural pore is
seen here and there.

Fig. 2. Transverse section of a specimen of Favosites Goi/ila?tdica, \d.r. favosa,
Gold., from the Hamilton Group (Devonian) of Erie Co., New York, en-
larged five times. Some of the corallites show the marginal foldings of
the tabulffi as so many dark spaces.

Fig. 3. Upper and under surfaces of an exceedingly young specimen of Favo-
sites Gothlandica, Lam., from the Wenlock Limestone of Dudley, of the
natural size.

Fig. 4. Outline of part of the upper surface of the corallum of a specimen of
F. Gothlandica, var. favosa, Gold., from the Niagara Limestone of Mani-
toulin Island, of the natural size ; and a single corallite enlarged four
times to show the marginal depressions or plications of the tabulae.

Fig. 5. A few corallites of a specimen of F. Gothlandica, from the Niagara
Group of Manitoulin Island, with well - developed septal spines {Astro-
cerium of Hall), of the natural size, and one corallite enlarged four times.

Fig. 6. Transverse section of Favosites Gothlandica, var. Billings ii, Rom., from
the HamiltoL Group of Arkona, Ontario, enlarged five times.

Fig. 7. Transverse section of an adult example oi Favosites Forbesi, E. and H.,
from the Wenlock Limestone of Stoke-Edith, enlarged five times.

H.Alleyne Nicholson del.

Plate. 1.

C.Pei-ieaulith.

Mira.em Bros imp.

PLATE II.

Fig. T. A young and nearly globular specimen of Favosites Forbesi, E. and H.,

from the Wenlock Limestone of Dudley, of the natural size.
Fig. I a. Upper portion of the vertical section of a similar specimen of the

same species, from the Wenlock Limestone of Benthall Edge, enlarged

five times.
Fig. I b. Transverse section of another young example of the same species,

from the Wenlock Limestone of Dudley, enlarged five times.
Fig. 2. A young specimen of Favosites Forbesi, E. and H., var. Waldronensis,

Nich., from the Niagara Group of Waldron, Indiana, of the natural size.
Fig. 2 a. Part of a tangential section of another young example of the same,

from the same locality, enlarged five times.
Fig. 2 b. Vertical section of the same species, enlarged five times.
Fig. 3. Transverse section of Favosites Fo?-besi, E. and H., var. Ei/cle/isis,

Nich., enlarged five times, showing the well-developed septa.

H.Alleyne Nicholson del.

Plate. 11.

C.Berjeau lith.

Minte.ru Bros imp.-

PLATE III.

Fig. I. An example of Favosites Forbest, E. and H., var. Eifekusis, Nich., from

the Devonian of Gerolstein in the Eifel, of the natural size.
Fig. I a. Portion of the surface of the same, enlarged twice.
Fig. I b. Vertical section of the same, enlarged five times, showing the septal

spines, seen laterally and in cross-section, as well as the tabulae.
Fig. 2. A very young example of Favosites Forbesi, E. and H., var. tubcrosa,

Rom., from the Corniferous Limestone of Port Colborne, Ontario, of the

natural size. The calices in the lower part of the corallum are closed by

an epithecal or opercular growth.
Fig. 2 a. Portion of the surface of a large and fully-grown example of the same,

from the same locality, of the natural size. The lower calices have

undergone closure by the epitheca.
Fig. 2 b. Portion of the surface of a large specimen of the same, from the

Hamilton formation of Arkona, Ontario, of the natural size.
Fig. 2 c. Transverse section of a specimen of the same, from the Hamilton

formation of Arkona, Ontario, enlarged five times.
Fig. 2 d. Part of a vertical section of the same specimen as the last, enlarged

five times. Besides the tabulae proper, the section shows some of the

peculiar transverse squamae, or incomplete tabulae, characteristic of this

peculiar form.
Fig. 2 e. Portion of two corallites of a silicified example of the same, from the

Corniferous Limestone of Port Colborne, Ontario, enlarged three times.

The interior of the tubes exhibits the peculiar transverse squamae above

alluded to, and the mural pores are also seen.
Fio-. 3. Transverse section of Favosites {Etmnojisia) hemisphcerica, Yand. and

Shumard., enlarged five times, from the Corniferous Limestone of Port

Colborne, Ontario.
Fig. 3 a. Portion of one of the tubes of the same specimen, similarly enlarged,

showing the close-set biserial mural pores.
Fig. 3 b. Portion of a vertical section of the same specimen, in which the

tubes are quite empty, enlarged five times, showing the incomplete and

flexuous tabulae.
Fig. 4. Portion of a transverse section of Favosites Bowerbanki, E. and H.,

from the Wenlock Limestone of Benthall Edge, enlarged five times.

Several of the corallites show an incomplete division of their tubes by

means of laminae directed inwards.
Fig. 4 a. Transverse section of a single corallite of the same specimen, show-
ing incompleted fission, enlarged ten times.
Fig. 4 b. Part of a vertical section of the same species, from the Wenlock

Limestone of Gotland, enlarged five times, showing the tabuL-e and mural

pores.

H. Alleyne Nicholson, del.

Plate. III.

^0^

m

CBerjeau.lith.

Mntem Bros

imp.

PLATE IV.

Fig. I. Portion of the corallum oi Favositcs clousus, Rom., from the Hamilton

formation (Devonian) of Arkona, Ontario, of the natural size. In the upper

portion of the specimen the calices are open.
Fig. \ a. K few of the calices of the same, closed with an operculum, enlarged

five times.
Fig. I b. Tangential section of the same, enlarged five times.
Fig. I c. Vertical section of the same, enlarged five times.
Fig. 2. Pachypora lamdllcornis, Lindst., from the Upper Silurian of Gotland, of

the natural size.
Fig. 2 a. Portion of a tangential section of the same, showing the dense

secondary deposit of sclerenchyma in the interior of the tubes, enlarged

seven times, with a single corallite enlarged still further, to show the

rudimentary septa.
Fig. 2 b. Portion of a longitudinal section of the same, similarly enlarged,

showing the thick walls, remote tabulee, and mural pores.
Fig. 2 c. Portion of the surface of the same, enlarged five times.
Fig. 3. Portion of the corallum oi Pacliypora {Favosites) cervicortiis, De Blainv.,

from the Devonian of Gerolstein in the Eifel, of the natural size. The

calices are omitted over the greater portion of the surface.
Fig. 3 a. Portion of the surface of the same, enlarged about six times.
Fig. 3 b. Portion of a tangential section of a specimen of the same, in which

the cavities of the fossil are filled with oxide of iron, enlarged seven times.

The thickening of the walls of the corallites is shown, as well as the lateral

communication of the visceral chambers of some of the corallites.
Fig. 3 c. Portion of a transverse section of the same, taken in the axis of a

branch, similarly enlarged, showing how greatly the tubes are narrowed by

secondary deposits of sclerenchyma, the original walls still remaining

quite distinct.
Fig. 3 d. Portion of a longitudinal section of the same, enlarged seven times,

showing the great and irregular thickening of the corallites near their

mouths, together with remote tabular, and large-sized mural pores. The

specimen is partially infiltrated with oxide of iron.
Fig. 4. Small and imperfect specimen of Pachypora (Favosites) cristata, E. and

H., from the Wenlock limestone of Dormington, near Stoke-Edith, of the

natural size.
Fig. 4 a. Portion of the surface of the same, enlarged five times.
Fig. 4 b. Portion of the surface of a specimen of Pachypora {Faiiosites) cristata,

var. major, E. and H., from the same locality, similarly enlarged.

H.Alleyne. Nicholson del .

Plate. lY

C.Berieau.lith

Mintem Bros imp.

PLATE V.

Fig. I. Transverse section oi Pachypora {Favosifes) cristata, E. and H., enlarged

seven times, showing the thickening of the tubes by a secondary deposit

of sclerenchyma. From the Wenlock Limestone of Dormington, near

Stoke-Edith.
Fig. I a. Vertical section of the same, showing the thickened walls, tabulae,

and mural pores, enlarged seven times.
Fig. I b. Vertical section of another specimen of the same, from Benthall

Edge, showing the tabulae, together with numerous septal spines ; enlarged

seven times.
Fig. 2. Fragment of Striatopora Li/meana, Billings, from the Hamilton forma-
tion of Ontario, of the natural size.
Fig. 2 a. A small portion of the surface of the same, enlarged five times.
Fig. 2 b. Transverse section of a branch of the same, enlarged seven times.
Fig. 2 c. Portion of a tangential section of the same, enlarged seven times,

showing the thickened walls, and spine-like septa.
Fig. 2 d. Part of a vertical section of the same, enlarged seven times, showing

the thickened walls, the occasional tabulas, and the mural pores.
Fig. 3. Fragment of Trachypora ornata, Rom., from the Hamilton formation

of Erie County, New York, of the natural size.
Fig. 3 a. Small portion of the surface of the same, enlarged five times, showing

the ornamentation.
Fig. 3 b. Vertical section of the same, enlarged seven times, showing the

thickened walls, the occasional tabulae, the numerous spiniform septa, and

the few mural pores.
Fig. 3 c. Tangential section of the same, enlarged seven times, showing the

thickening of the walls by concentric lamellae of sclerenchyma and the

rudimentary septa.
Fig. 4. Fragment of Ti-achypora elegantula, Bill., from the Hamilton Group of

Arkona, Ontario, of the natural size.
Fig. 4 a. Small portion of the surface of the same, enlarged five times, showing

the peculiar ornamentation.
Fig. 4 b. Transverse section of a branch of the same, enlarged five times.
Fig. 4 c. Vertical section of a branch of the same, enlarged seven times, show-
ing the immense thickening of the corallites by the deposition in their

interior of successive laminae of sclerenchyma.

H. Alleyne Nicholson del .

Plate. \;

CBerjeaulith.

MinternBros imp.

PLATE VI.

Fig. T. A colony of Verniipora claiiso, Lindst., from the Upper Silurian of
Gotland, enlarged twice.

Fig. I a. Transverse section of the same, enlarged seven times, showing spini-
form septa.

Fig. I /;. Vertical section of the same, enlarged seven times, showing tabulas
and mural pores.

Fig. 2. Portion of the surface of the corallum oi Alveolites suborbicularis^ Lam.,
from the Eifel, enlarged seven times, showing no apparent traces of the
single septal ridge.

Fig. 2 a. Portion of a tangential section of the same, also from the Eifel, show-
ing the form of the corallites. A few of the tubes show a single septal
tooth. Enlarged twelve times.

Fig. 2 h. Vertical section of the same, enlarged twelve times, showing tabulae.
The section cuts the tubes at right angles to their long diameters.

Fig. 3. Tangential section of Alveolites Labechei, E. and H., from the Upper
Silurian of Benthall Edge, enlarged twelve times, showing the compressed
tubes and well-developed spiniform septa.

Fig. 3 a. Vertical section of the same, enlarged twelve times, showing the
spiniform septa, and the tabulae. The section cuts the corallites parallel
with their short diameters.

Fig. 4. Portion of a tangential section of Alveolites Goldfiissi, Bill., from the
Hamilton Group (Devonian) of Canada, enlarged twelve times, showing
the thin-walled compressed tubes, and the absence of septal spines or
ridges.

Fig. 5. A fragment of Co'iiites jimiperinus, Eichw., of the natural size, and en-
larged five times. From the Wenlock Limestone of Stoke-Edith.

Fig. 5 a. Part of a vertical section of the same, enlarged twelve times, show-
ing the thickening of the tubes close to the mouths, the tabulae, and the
mural pores.

Fig. 5 b. Portion of a transverse section of a branch of the same, enlarged
twelve times, showing the compressed corallites in the axis of the stem,
with unthickened walls.

H.AlIeyne Nicliolson del.

Plate VL

CBerjeaulith.

MinteiTi Bros imp.

PLATE VII.

Fig. r. Fragment of a laminar specimen of Cxnites Ihiearis, E. and H., of the
natural size, from the Wenlock Limestone of Benthall Edge.

Figs. I 'a and i b. Different forms of the calices of the same, enlarged eight
times.

Fig. I c. Tangential section of the same, enlarged twelve times.

Fig. I d. Portion of a section of the same, taken at right angles to the flat
surfaces of the expansion, enlarged twelve times, showing the great thick-
ening of the tubes as they bend outwards to the surface.

Fig. I e. Portion of a longitudinal section of the same, taken through the
median plane of the corallum, enlarged twelve times, showing tabulae and
mural pores.

Fig. 2. A small specimen of Columnopora cribrifonnis, Nich., from the Cincin-
nati Group of Ohio, of the natural size, viewed from above.

Fig. 2 a. Portion of a tangential section of a specimen of the same, from the
Cincinnati Group of Ohio, enlarged five times, showing the rudimentary
septa, the mural pores, and the " intramural canals." The visceral cavities
are filled with the matrix.

Fig. 2 b. Cross-section of a single corallite of the same, enlarged ten times,
showing the " intramural canals."

Fig. 2 c. Part of a vertical section of another specimen of the same, from the
Cincinnati Group (Hudson River Group) of the Credit River, Ontario, en-
larged five times. In parts the section cuts through the centre of the
tubes, and shows the inosculating tabulae ; but in other parts it more or
less nearly coincides with the plane of the walls of the corallites, and shows
the large and numerous mural pores.

Fig. 2 d. Part of the preceding section, enlarged ten times, showing the cribri-
form wall.

Fig. 3. Fragment of Laccripora cribrosa, Eichw., of the natural size. (After
Eichwald.)

Fig. T, a. Surface of the same, enlarged. (After Eichwald.)

Fig. 3 b. Longitudinal section of the tubes of the same, enlarged. (After
Eichwald.)

H . Alle^Tie Nidiol s on del

Plale VII,

'■^^^i^^^^v^t^

fli?^^*^*^

*^U.s.,>-

C.Berjeau lith.

Mintern Bros imp.

PLATE VIII.

Fig. I. Section of the corallum of Pleurodidyum stylophorum, Eaton., taken
parallel with and just above the flat base, enlarged two and a half times,
showing the tabulse, pores, and rudimentary septa. The sections of the
" vermiform body " are left white, for clearness' sake. From the Hamilton
Group (Devonian) of the State of New York.
Fig. I a. Part of a tangential section of the same, similarly enlarged. A few
mural pores are seen in section; and the sections of the "vermiform
body" are, as before, left white, except in one place where some dark
ovoid bodies occur within its cavity.
Fig. I b. Vertical section of a specimen of the same, similarly enlarged, show-
ing the inosculating tabula and mural pores. The visceral chambers of
all the corallites, except one, are filled with the matrix, and the sections of
the " vermiform body " are, as before, left unshaded.
Fig. 2. Portion of the corallum of Chonostrgites Clappi, E. and H. { = Haimeo-
" phylliim ordinatum, Bill), of the natural size, viewed laterally. Corniferous
Limestone (Devonian), Walpole, Ontario.
Fig. 2 a. Portion of the upper surface of a broken corallum of the same, of
the natural size, showing the convex tabula, and the upper surfaces of the
lateral connecting-floors.
Y\". 2 b. Part of a transverse section of the same, enlarged twice. The actual
corallites are cut across transversely, but the lateral connecting-floors are
only seen where their undulations happen to bring them into the plane of
the section.
Fig. 2 c. Part of a vertical section of the same, enlarged twice, showmg the
form and mode of increase of the corallites, their hollow and vesicular
lateral connecting- floors, and the inosculating and subvesicular tabulae,
the upper surfaces of which are serrated with spiniform projections. Both
this and the preceding drawing (fig. 2 b) are taken from sections of a
specimen in which the tubes are exceptionally wide apart.
Fig. 3. Small specimen oi Lyopora favosa, M'Coy, sp., from the Lower Silurian
of Craighead, Girvan, of the natural size. (After Nicholson and R. Ethe-
ridge, jun.)
Fio-. -x a. A few calices of the same enlarged.

H. Alleyne Nicholson dd.

Plate VIIL

C.Beijeaulith.

Mmtern Bros imp.

PLATE IX.

Fig. I. Part of a vertical section of Stenopora ovata, Lonsd., from the Carbon-
iferous rocks of Queensland, enlarged about twenty-five times, showing the
periodical annular thickenings of the corallites, the remote tabulae, placed
at corresponding levels in contiguous tubes, and the mural pores.

Fig. I a. Part of a tangential section of the same specimen, taken just below
the surface, and similarly enlarged, showing the hexagonal form of the
tubes and the peculiar appearances which they present when the section
cuts them across their unthickened or thickened portions.

Fig. 2. Part of a tangential section of Lyopora favosa, M'Coy, sp., from the
Lower Silurian of Craighead, Girvan, enlarged eight times, showing the
rudimentary septa, and the thickened walls, in which a few small vacuities
are visible.

Fig. 2 a. Part of a vertical section of another specimen of the same, similarly
enlarged, showing the thick walls and the remote complete tabulae. As
in the preceding section, a few minute irregular vacuities are seen here
and there in the substance of the wall.

Fig. 3. Ks\)Q.c\m.enoi Nyctopora Biningsii, Nich., from the Trenton Limestone
of Canada, of the natural size ; viewed from above.

Fig, 3 a. Part of a transverse section of the same, enlarged eight times, show-
ing the complete fusion of the walls of the corallites, and the marginal
septa, together with an occasional mural pore.

Fig. 3 l>. Part of a vertical section of the same, enlarged eight times, showing
the tabulse and mural pores. Where the section cuts through the centre of
the tubes, the tabulae are alone seen; where the section passes nearly along
the plane of the wall of a tube, the marginal septa and mural pores are
brought into view.

Fig. 3 c. Small part of the surface of the same, enlarged ten times, showing the
calices.

Fig. 4. A small specimen of BiUingsia alvcolaris, De Koninck, from the De-
vonian of New South Wales, of the natural size (after De Koninck). The
corallum is split, and shows the large mural pores connecting contiguous
tubes.

H.Alleyne Nicliolson, del.

Plate IX.

Zcu

3i

^-"r^

si,.

m^

CBerjeau, litli

Vi'at erst on, Sons k Stewart, Liffi' Edra''

PLATE X.

Fig. I. Part of a transverse section of Columnaria alveolata, Goldf. ( = Favistella
stellata, Hall), enlarged five times, showing the characters of the septa.
From the Cincinnati Group of Ohio.

Fig. I a. Longitudinal section of a single tube of the same, similarly enlarged.
Owing to the curvature of the tube, the cut edges of the septa appear in
parts of the section.

Fig. 2. Part of a transverse section of Columnaria caliciiia, Nich., from the
Hudson River Group of Canada, enlarged five times, showing the structure
of the wall and the characters of the septa.

Fig. 2 a. K single tube of the same, in longitudinal section, similarly enlarged,
showing tabulee, and part of the cut edges of the septa.

Fig. 3. Part of a transverse section of Columnaria (?) Halli, Nich. ( = Colum-
naria alveolata, of Hall, Billings, &c.), enlarged five times, showing the
amalgamation of the walls of the corallites and the marginal septa.

Fig. 3 a. Part of a vertical section of the same, similarly enlarged,' showing the
tabulae. In part of the section the cut edges of the septa are seen.

Fig. 4. Part of a vertical section of Syringopora ge?iiculata, Phill., enlarged five
times. From the Carboniferous Limestone of Shap, Westmorland.

Fig, 4 a. Part of a transverse section of the same specimen, enlarged five times,
showing the thickened tubes.

Fig. 4 b. Transverse section of a corallite of the same, enlarged about twenty-
five times, showing the contraction of the visceral chamber by a secondary
deposit of sclerenchyma within the true wall.

Fig. 5. Transverse section of a single corallite of Syringopora reticulata, Goldf,
from the Carboniferous Limestone of Kendal, Westmorland, enlarged about
fifteen times, showing the spiniform septa, and the cut edges of the tabulce.

Fig. 6. Transverse section of a few of the tubes of Halysitcs escharoides^ Lam.,
from the Upper Silurian of Gotland, enlarged ten times, showing the spini-
form septa, and the apparent absence of any small zooids.

Fig. 7. Transverse section of a few of the tubes of Halysites catenularia, Linn.,
from the Wenlock Limestone of Dudley, enlarged five times, showing the
presence of small zooids and the absence of septa.

Fig. 7 a. Vertical section of another specimen of the same, enlarged five times,
showing the tabula of the larger and smaller zooids.

E. Alley ne Nicholson, del

Plate X.

C.Berjeau; lith.

Yfatersion, Sons L StewaTt.Iiih" Edin'^

PLATE XI.

Fig. I. Transverse section of a few of tlie tubes of Halysiies catenularia, Linn.,
from the Wenlock Limestone of Dormington, Stoke-Edith, enlarged ten
times, showing the absence of septa in the large tubes, and the structure
of the intermediate tubes. The epitheca is left unshaded.

Fig. I a. Part of a vertical section of another specimen of the same, from the
same locality, enlarged five times. The specimen is one in which the
tubes are of unusually large size, and the tabulae of the intermediate tubes
are subvesicular.

Fig. 2. Portion of the surface of Thecia Swiudcrnana, Goldf , enlarged about
ten times. Wenlock Limestone, Dormington Quarry, Stoke-Edith.

Fig. 2 a. Part of a transverse section of the same, enlarged ten times, showing
the obtuse septal ridges, the communication of the cavities of the polypes
by horizontal channels, and the filled-up tubuli of the interstitial tissue.

Fig. 2 b. k. small part of the same transverse section, enlarged twenty times,
showing the filled-up interstitial tubuli.

Fig. 2 c. Part of a vertical section of the same, enlarged ten times, showing the
tabulate larger corallites, the horizontal canals uniting the visceral cham-
bers of these, and the small tubules of the interstitial tissue.

Fig. 2 d. Small portion of the same section, enlarged twenty times, showing the
interstitial tubuli.

Fig. 3. Part of a transverse section of Fropora tid>i//afa, E. and H., enlarged
five times, from the Wenlock Limestone of Dudley. The specimen is one
in which the septa are unusually small and short.

Fig. 3 a. Part of the same section, enlarged ten times.

Fig. 3 b. Part of a vertical section of the same specimen, enlarged ten times.

Fig. 4. Portion of the surface of an altered specimen of Lyellia glabra, E. and
H., from the Upper Silurian of Iowa, of the natural size (copied from
Edwards and Haime).

Fig. 4 a. Portion of a specimen oi Lyellia glabra, E. and H., seen from one
side, enlarged (copied from Edwards and Haime).

Fio-. 5. Part of a tangential section oi Plasmopora petaliformis, E. and H., from
the Wenlock Limestone of Gotland, enlarged five times.

H-Alleyne "Nicliolson, del.

Plate XL

C. Berjeau, lith

■Waterston, Sons 3^, Stewart, LitH^ Edm''

PLATE XII.

Fig. I. Part of a vertical section of a young specimen of Plasmopora petaliformis,
E. and H., from the Wenlock Limestone of Dudley, enlarged five times,
showing the faintly-marked walls of the smaller corallites, and their convex
tabulae.

Fig. 2. Portion of a tangential section of Heliolitcs inegastoma^ M'Coy, from the
Wenlock Limestone of Dudley, enlarged five times.

Fig. 2 a. Part of a vertical section of the same specimen, enlarged five times,
showing the comparatively well-marked walls of the smaller corallites and
their strong horizontal tabulae.

Fig. 3. Under surface of a small specimen of Pbiacopora Grayi, Nich. and
Eth. jun., from the Lower Silurian of Girvan, Ayrshire, of the natural size,
showing the concave base, with its concentrically-striated epitheca.

Fig. 3 a. Upper surface of another specimen of the same, from which all the
short corallites except a few on one margin have been denuded, leaving the
superior aspect of the epithecal plate to view, of the natural size.

Fig. 3 b. Portion of the corallum of the same, as naturally split along a hori-
zontal plane, showing the large and small corallites, with their visceral
chambers filled with dark matrix, — enlarged five times.

Fig. 3 c. Part of a vertical section of the corallum of the same, embedded in
an opaque matrix, — enlarged five times.

Fig. 3 d. Tangential section of another specimen of the same, infiltrated with
calcite, showing the large and small corallites (/, / and /, /),- — enlarged
twenty times.

Fig. 3 e. Vertical section of another example of the same, enlarged twenty
times, showing the large corallites (/, /), and the smaller and more closely
tabulate tubes {t, t). [Figs. 3-3 e are copied from the " Monograph of the
Silurian Fossils of Girvan," by R. Etheridge, jun., and the author.]

Fig. 4. Tangential section of a specimen of Chcetetes radia/is, Fischer, from the
Carboniferous Limestone of Russia, showing the thick and completely
confluent walls of the corallites, with an occasional inward projection in-
dicative of commencing fission, — enlarged ten times.

Fig. 4 a. Vertical section of the same, enlarged ten times, showing the remote
and regularly placed tabulae.

Fig. 4 b. Portion of surface of the same, enlarged ten times, showing the form
of the calices.

Fig. 4 c. Portion of a tangential section of a specimen of the same, from the
Carboniferous Limestone of Shap, Westmorland, enlarged ten times.

Fig. 4 ^. A small portion of the same section as the last, enlarged twenty
times, showing the complete amalgamation of the walls of the tubes, and
the presence in some of the tubes of the inward projections produced in
tlie process of fission of the old corallites.

HAlleyne ITicTiolsoTi, del

Plate All.

Wateiston.Sons & Stewa.it, Littf' Edirf

C. Berjeau, hth.

PLATE XIII,

Fig. I . Part of a tangential section of Monticulipora {Heterotrypd) mammulata,
D'Orb., from the Cincinnati Group of Cincinnati, Ohio, enlarged twenty
times, showing the two sets of corallites.

Fig. I a. Small portion of the preceding section, enlarged fifty times, showing
the structure of the walls, and the occasional presence of spines (modified
corallites).

Fig. I b. Part of a vertical section of the same species, enlarged twenty times,
showing the different disposition of the tabulte in the two sets of corallites
respectively.

Fig. 2. Part of a tangential section of Monticulipora {Heterotrypa) ramosa, F.
and H., from the Cincinnati Group of Cincinnati, Ohio, enlarged twenty
times, showing' the two sets of corallites.

Fig. 2 a. Part of a vertical section of the same species, enlarged twenty times,
showing the different disposition of the tabulae in the two sets of tubes.

Fig. 3. Under surface of a specimen oi Monticulipora {DipIot)'ypa) pdropolitana,
Pand., from the Lower Silurian rocks of Sweden, of the natural size, show-
ing the epithecal plate.

Fig. 3 a. The same specimen, viewed in profile, of the natural size.

Fig. 3 b. Part of a tangential section of the same, enlarged twenty times, show-
ing the uniformly thin walls of the corallites, and the small angular tubes
wedged in at the angles of junction of the larger ones.

Fig. 3 c. Part of a vertical section of the same, showing the two sets of tubes,
and the increase in the number of the tabulae as the exterior is approached,
— enlarged twenty times.

Fig. 4. Under surface of Monticnlipora {Diplotrypd) WJiiteavesii, Nich., of the
natural size, showing the concave base and epithecal plate. From the
Trenton Limestone of Peterboro', Ontario.

Fig. 4 a. The same specimen viewed in profile.

Fig. 4 b. Part of a tangential section of the same, enlarged twenty times, show-
ing the different groups of corallites.

Fig. 5. Side view of a specimen of Monticulipora {Monotrypa) IVinteri, Nich.,
of the natural size, from the Devonian Limestone of Gerolstein in the
Eifel.

Fig. 5 a. Under surface of the same, of the natural size, showing the epithecal
plate partially removed by weathering.

H-.A^leyne IMcliols or., ie

Plate XIII.

C.Berjeau.litli.

Wateiston, Sons &. Stewart LitW^ Sdra

Off J httR ,gIl£V/

'd? ?9m'

PLATE XIV.

Fig. I. Portion of a vertical section of MonticuUpora {Diplotrypa) IVhiteavesii,
Nich., from the Trenton Limestone of Peterboro', Ontario, enlarged twenty
times, showing the closely-tabulate small corallites, and the twofold con-
stitution of the tabulee of the large corallites.

Fig. 2. Part of a tangential section of MoiticuHpora [Monotfypa) JJ'interi,
Nich., from the Devonian Limestone of Gerolstein in the Eifel, enlarged
twenty times, showing the thin-walled polygonal corallites, with an occa-
sional young tube intercalated.

Fig. 2 a. Part of a. vertical section of the same, showing the thin walls, and the
uniform development of the tabulae of all the corallites.

Fig. .3. A medium -sized specimen of MonticuUpora {Monoirypa) nndidata,
Nich., from the Hudson River Group of Toronto, Ontario, of the natural
size. The specimen is broken on one side.

Fig. 3 a. Part of a tangential section of the same, enlarged twenty times, show-
ing the thin-walled, and nearly equal-sized corallites.

Fig. 3 b. Part of a vertical section of the same, enlarged twenty times, show-
ing the thin and undulated wallSj and the uniform development of the
remote tabulae.

Fig. 4. Part of a tangential section of MonticuUpora {MoJiotrypa) undulata,
Nich., from the Trenton Limestone of Peterboro', Ontario, enlarged
twenty times.

Fig. 4 a. Part of a vertical section of the same, enlarged twenty times, showing
the thin undulated walls, and the remote tabulae placed at corresponding
levels.

Fig. 5. One of the star-like elevations of tlie surface of ConstcUaria aiitheloidca.
Hall, from the Cincinnati Group of Ohio, enlarged.

Fig. 5 a. Part of a tangential section of the same, taken just below the surface,
enlarged twenty times. The upper part of the portion figured traverses
one of the stellate areas or " maculae," while the lower part cuts across a
portion of the general surface.

Fig. 5 b. Part of a vertical section of the same, showing the two sets of coral-
lites, enlarged twenty times.

Fig. 6. Part of a tangential section of a typical example of MonticuUpora pul-
chella, E. and H., from the Wenlock Limestone of Dudley, enlarged
twenty times. The section cuts across one of the clusters of large
corallites.

Fig. 6 a. Small portion of a longitudinal section of the same specimen, show-
ing the characters of the corallites just before they open on the surface,
enlarged twenty times.

H.Alleyne T^ictolson, lei

Plate XIV,

C. Berjeaii, litli.

"Waterston, Sons &, Stewart, litH^ EJto''

PLATE XV.

Fig. I. Fragment of Dckayia attrita, Nich., from the Cincinnati Group of Ohio,
of the natural size.

Fig. I a. Portion of the surface of the same, enlarged.

Fig. I I). Tangential section of the same, enlarged twenty times, showing the
spiniform corallites scattered among the ordinary tubes.

Fig. I c. Vertical section of the same, enlarged twenty times, showing the
characters of the two sets of corallites just before they open on the
surface.

Fig. 2. A small specimen of Fistiilipora {Callopora) proporoides, Nich., from
the Hamilton Group of Canandaigua, State of New York, of the natural
size.

Fig. 2 a. Part of the surface of the same, enlarged. The large circular tubes
have projecting and open calices, but the mouths of the interstitial angular
tubes are mostly closed by a calcareous mennbrane, and the lines of divi-
sion between them are only faintly indicated.

Fig. 3. Part of the surface oi Fisiulipora {Callopora) incrassata^ Nich., from the
Hamilton Group of Arkona, Ontario, enlarged. The mouths of the in-
terstitial corallites are seen in the specimen figured ; but they are often
concealed from view by a calcareous membrane.

Fig. 3 a. Part of a tangential section of the same, enlarged twenty times,
showing the oval corallites with a slight constriction on one side, sur-
rounded by a series of angular corallites.

Fig. 3 b. Part of a vertical section of the same, enlarged twenty times, showing
the remotely-tabulate oval tubes, and the vesicular tabulae of the angular
corallites.

Fig. 4. Part of a tangential section of Labcchia co>iferfa, E. and H., from the
Wenlock Limestone of Benthall Edge, enlarged ten times, showing the
primitively tubular condition of the pillars, and the transversely-divided
edges of some of the vesicular tabulae.

Fig. 4 a. Part of the upper surface of another specimen of the same, from the
same locality, enlarged. The surface-tubercles in the specimen figured
are more extensively confluent than is usually the case.

A. H ¥1011015011, del.

Plate XV.

C.Berjeau, lifn.

Waterston, Sons &, Stewart Litli" E Jm'

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VI.

INTRODUCTION TO THE STUDY OF BIOLOGY.

Crown 8vo, with numerous Engravings 5s.
VII.

A MANUAL OF PALAEONTOLOGY.

For the Use of Students.

With a General Introduction on the Principles of Pal/eontologv.

Crown 8\o, with upwards of 400 Engravings. 153.

' ' Tills book will be found to be one of the best of guides to the principles of Palceontology and
the study of organic remains." — Athciuvitm.

THE ANCIENT LIFE-HISTORY OF THE EARTH.

An Outline of the Principles and Leading Facts of Pal^ontological
Sci.ence. With a Glossary and Index

Crown Svo, with 270 Engravings. los. 6d.

" By a master in the science, who understands the significance of every phenomenon which he
records, and knows how to make it reveal its lessons. As regards the value of the work, there can
scarcely exist two opinions. As a text-book of the historical phase of Palceontology it will be indis-
pensable to students, whether specially pursuing Geology or Biology ; and without it no man who
aspires even to an outline knowledge of Natural Science can deem his library complete." — Quarterly
Jojirnal of Science.

IX.

MONOGRAPH OF THE BRITISH GRAPTOLITID^.

Part I. — General Introduction.
With 74 Engravings, Svo, pp. 133. 5?.

WILLIAM BLACKWOOD & SONS, Edinburgh and London.

Date Due

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