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THE ACTINIARIA OF THE SIBOGA EXPEDITION

PART I

CERIANTHARIA

Sib o ga-Exp editie

XV a

THE

ACTINIARIA OF THE SIBOGA EXPEDITION

BY

DR J. PLAYFAIR Mc MURRICH

L'niversity of Tovonto, Canada

PART I

CERIANTHARIA

With 1 plate and 14 text figures

(Aided by a grant from the EL1ZABETH THOMPSON SCIENCE FUND)

»8>&®fr«8<=—

late E. J. BRTLL

PUBUSHERS AND PRINTERS

LEYDEN I9IO

.• LI

PART I

CERIANTHARIA

Before entering upon the special matter of this Report a few remarks seem necessary
in explanation of the classification that has been adopted. The classification of the Anthozoa
has undergone many changes as increasing knowledge of the structural peculiarities of the forms
assigned to the group has revealed the manifold differences of their organization. An historical
review of these changes is unnecessary here, as I have already (1893) given an account of the
principal ones up to 1 89 1 , and a somewhat more thorough review, brought up to date, has
recently been given by Carlgren in the Anthozoa of Bronn's Thierreich (1908). Within recent
years two classifications have been proposed as the result of extensive studies of groups of the
Anthozoa and to these I desire to refer briefly, since the classification I am adopting here
differs from both in certain particulars while agreeing in others. One of these classifications is
that proposed by van Beneden (1898) and the other that of Carlgren, in the work just cited.
Van Beneden, after a thorough discussion of the questions at issue, divides the Anthozoa into
three great groups, the Zoanthactiniaria, Octactiniaria and Scyphactiniaria. The first of these
groups is again subdivided into the Zoanthinaria, equivalent to Hertwig's tribe Zoantheae, and
the Hexactiniaria which includes the Actiniaria and the Madreporaria. The Octactiniaria correspond
to the group more usually known as the Alcyonaria ; the Scyphactiniaria are divisible into three
subgroups, the Ceriantharia, including the Ceriantharia and the Antipatharia, the Scyphomedusae

and the Rusfosa. In tabular form the arrangement is as follows

Anthozoa

Zoanthactiniaria . .

Zoanthiniaria
Hexactiniaria

Octactiniaria

Scyphactiniaria

Ceriantipatharia.
. I Scyphomedusae

l Madreporaria
(Actiniaria

(Ceriantharia
(Antipatharia

5479*

Rugosa

SIBOG A-EXPEDITIE XV ö.

[*o the principle involved in the firsl of these groups I would offer no objections, the

inthiniaria undoubtedly standing in closer phylogenetic relationship to the II' actiniaria than
to any of the other groups, and just as undoubtedly the Madreporaria ai ly related to

the Actiniaria, an idea sug by Hertwig and abundantly confirmed by recent studies oi

the soft parts and development of the coralligenous forms (see especiallj Duerden, 1902 With

,r>l to the third group, however, I am entirely in disaccord. In the first place 1 cannot

elationship that the arrangement predicates for the Ceriantharia and Antipatharia.

Indications of affinity van Beneden finds in the presence in both groups ol a longitudinal

idermal musculature in the column wall, in the weak development of the mesenterial mus-
culature and in the similarity in the arrangement of the principal mesenteries. The first two
characters do not seem to me to be entitled to great importance, occurring and disappearing
.is they do in various groups of Anthozoa; the third is of significance. But is there similarity in
this Van Beneden finds it by recognizing but three protocnernes in the Ceriantharia

and in this 1 believe he is mistaken. I can sec no reasons for regarding the fourth couple ol
m. , that appear in Cerianthan larvae as other than protocnernes, and in later pages ol

this Report I shall present further evidence that is afforded by the development in favour of
this view. 1 hope to show that the development <>f what I shall term the deuterocnemes in the

riantharia begins with the fifth couple of mesenteries and that, consequently, the members
of that group take origin from an octamerous condition. Whether the Antipatharia really start
trom an hexamerous condition in which there are only three couples ol protocnernes or not

.not be determined with certainty at present; we must wait tor further light on the «piestion,
until. perhaps, a study of the embryonic development ^\ some member of the group may offer
data for a final conclusion. In the mean time it seems that any such close alliance of Ceriantharia
and Antipatharia as van Beni den has proposed is inadvisable.

In the association of the Scyphomedusae with the Ceriantharia, etc, I believe van Beneden
has also fallen into error. Certainly these medusa are more nearly related to the Anthozoa than
;■■ the I Ivdromedtisa-, but instead of forming a suli^roup of a subgroup of the Anthozoa the\
should be of equal value with that group. Their relationship traces back only to remote ancestors,
to a stage before the differentiation of the Alcyonaria, Ceriantharia, etc, and to make the
phomedusse equivalent to these is an imperfect expression of their phylogenetic atlmities.
Finally, with regard to the Rugosae it seems probable that van Beneden himself, with
the results obtained by DüERDEN (1905) now at his disposal, would materially alter his views
as to their affmities and recognizc their close relationship to the Zoanthactiniaria. The evidence
which Duerden has presented as to their primary hexactinian characters seems wel) founded,
and while I am not inclined to recognize tbr them so close an affinity to the Zoanthinaria
he suggests, nor \ et to follow Carlgren in including them among the Madreporaria. yet I

lieve there is reason for associating them with both these groups to the same extent that
in associates the Zoanthids and Hexactinians.
I would accordingly do away with van Beneden's group Scyphactiniaria and frame a
much more resembling that proposed by Carlgren (1908), though differing trom
this in tlv n assigned to the Rugosae. Carlgren's classification is as follows:

Anthozoa

Hexacorallia .
Octocorallia. .

Dodecacorallia

Antipatharia

Ceriantharia

Zoophytaria

Zoantharia

Actiniaria

Madreporaria

In this, again, there is a closer association of the Antipatharia and Ceriantharia than
seems advisable, nor should the Madreporaria be separated as distinctly from the Actiniaria as
are the Zoantharia. Exception may also be taken to the nomenclature employed in both this
and van Beneden's classification, on the ground that in the latter the terminations adopted do
not sufficiently differentiate subgroups from groups, while in the former the term Hexacorallia
is apt to be misleading both on account of its form and on account of the different sense in
which hexamerism has been understood.

I would suggest an arrangement and nomenclature somewhat as follows, as representing
fairly accurately our present information as to the affinities of the various groups.

Alcyonaria

Antipatharia
Ceriantharia

Anthozoa.

Zoanthactiniaria

Hexactiniae.
Zoantheae

Rugosae

Madreporacea
Actiniacea

This is essentially the classification I proposed in my paper on the Phylogeny of the
Actinozoa (1891), except that the Edwardsiae are now included in the Hexactiniae and the
Zoantheae and Rugosae are brought into closer relationship to the same group. This is in
accordance with the views I have held as to the significance of the development of the mesen-
teries in the different groups. It seems quite certain, both from the comparative study of adult
forms and from the embryological development, that a condition with eight mesenteries, developed
in couples, is well marked in all the Anthozoan groups with the possible exception of the
Antipatharia. Whether these are to be regarded as possessing only six mesenteries, comparable
to the eight of the other groups, or whether they are to be regarded as modifications from a
primarily eight mesenteried stage remains for demonstration, as does also the question of the
significance of all the additional mesenteries occurring in such a form as Leiopathes. In the
Alcyonaria the primary eight mesenteries are the only ones present, but in the Ceriantharia
and Zoanthactiniaria additional mesenteries are added. In the former group these are always
developed in couples, and this is also the case with the four mesenteries which succeed the

3

primaries in th<- Zoanthactiniaria, bul while in the Ceriantharia tl ondary mesenteries

always retain the coupled condition, in the Zoanthactiniaria they form pairs with tli<- lateral
primary mesent an hexamerous symmetry, with the mesenteries in six pairs, being tlms

produced. Finally in th<- Zoanthactiniaria a tertiary group of mesenteries is added, these mesenteries,
as a ruif. being developed in pairs.

h seems convenient to have distinguishing terms for these three groups of mesenteries.
ied the use of the term protocnenv - for the mesenteries constituting
the si\ primary j >.iirs of the Zoanthactiniaria, that is to say for th<- primary and secondary
:nteries recognized above, and for the additional coupled mesenteries of the Cerian-
tharia and for the paired «mes of the Zoanthactiniaria hc employed the term metacnemes. This
nomenclature is open to the objection that it disregards the significance of the eight mesenteried
stadition found in the Alcyonaria and the Zoanthactiniarian larvse and almost implies that this
condition is a derivative from a six-paired one; further it makes the secondary coupled mesenteries
of the Ceriantharia equivalent to the paired tertiaries of the Zoanthactiniaria. I would limit the
term protocneim ^ to the eight primary coupled mesenteries. and for the secondary coupled
1 would suggest the term deuterocnemes, while for the mesenteries which succeed
these in the Zoanthactiniaria and which usually develope in pairs I propose the term zygocnemes.
I i rden's term metacnemes might be employed either for these or for the deuterocnenn-s, but
to avoid any confusion that might result from its application in a new sense it has seemed
preferable to discard it.

CERIANTHARIA.

Our knowledge of the Ceriantharia dates from 1784 when Spallanzani gave a brief
description of the form now generally known as Ccrianthus mcmöranaceus, regarding it as a
somewhat aberrant Tubularia, to which genus Rapp (1829) also referred C. solitarius, first
described by him. In 1804 Renier, according to Meneghini (1847), had described C. membra-
naccus as Adinia cylindrica, thus associating it with the Actiniaria; in 1828 the same author
redescribed it as Moscata rododattila-, in 1830 della Chiaje assigned it to the genus Cerianthus
under the name C. cornucopi<?\ and in 1852 Milne-Edwards and Haime recognized a family
Cerianthidae, distinguished from the other Actiniaria by possessing a rounded aboral pole and
including Ilyanthus as well as Cerianthus. It was not until 1854, however, that Haime gave the
first detailed account of the anatomical peculiarities of a Cerianthid, showing that it possessed
many features distinguishing it from other Actiniaria, notably the arrangement of the tentacles
and the occurrence of the mesenteries in couples instead of in pairs. Von Heider (1879) enlarged
on Haime's observations, principally by the discovery of sterile mesenteries alternating with the
longer fertile ones which alone Haime had observed, and the brothers Hertwig (1879) confirmed
this discovery and added the important conclusion that in all probability the formation of new
mesenteries takes place only at one region of the body, namely, on either side of the dorsal
median line. Correlating the results of their studies, the Hertwigs recognized the fundamental
distinctness of the members of the genus Cerianthus from the other groups of Actiniaria, and
in 1882 R. Hertwig established for them and their cono-eners the order Cerianthese.

o

With the recognition of the distinctness of the Cerianthece arose the question of their
phylogenetic affinities to the other orders of Anthozoa. As already stated, the Hertwigs had
concluded on anatomical grounds that new mesenteries appeared in couples in a single mesenterial
chamber, namely, that which lies opposite the single large siphonoglyph, and von Koch (1SS0)
arrived at the same conclusion from observations made upon young larvse of C. mcmbranaceus.
The evidence brought forward by Vogt (1880) and H. V. WlLSON (1888) served to confirm
the Hertwigs' conclusions, and the matter was finally settled by the observations of Boveri
(1889) and myself on Arachnactis l).

At least it was settled so far as the development of all couples beyond and including

1) Kor a discussion of the systematic position of A. brachiolata see latei', under the genus Arachnactis.

5

fifth \\.is concerned, bul in 1 1 1 « - youngest individual observed by Boveri the lust four couples
already formed. I «ras fortunate enough to obtain a still yo larva of . /. brp.chiola.ta

in which but six mesenteries were formed, and by a comparison of tliis with older forms it was
determine, with ;i close approximation to certainty, the order of succession of the
couples, and this proved to 1"- identical with that which earlier observations had
shown to occur in the Hexactinians, and quite different froifl that of the later formed couples.
it appears, then, that there can be recognized in the Ceriantharia two sets of mesenteries,
the protocnemes, consisting of the first four couples, in which the order of succession is
similar to that occurring in the majority of Hexactinians, and a second, the deuterocm
consisting ol all the remaining mesenteries, which appear successively in couples in the di
intermesenterial chamber. This distinction was clearly recognized by both Boveri and im
and was represented by diagrams in our respective papers. As tliis matter is of some importance

in connection with the proper understanding of adult Ceriantharia
I venture to append a diagram illustrating the arrangement and
i irder of succession of the two sets i rexl figure l), the protocnemes
being represented in red and designated by roman numerals, while
the second set, the deuterocnemes, are represented in black
and designated by arabic numerals.

1 rom this diagram it will be seen that the order of
cession of the protocnemes, starting from the midventral line, is
III — I — II — IV. and the fust couple of deuterocnemes makes its
appearence in the intermesenterial chamber bounded by the two
i.ig. i. protocnemes belonging to the fourth couple. Comparing this

ing the probable succession sequence witn that indicated bv BoVERl in his figures, a discrepancv

the mesenteries in the Ceriantharia.

i iv, protocnen* is observable in that those protocnemic couples which I have

arded as being the third and fourth are taken by Boveri to
be the fourth and third respectively ; at least they are designated in his figures by d and c.
discrepancy, however, is an unimportant one, since Boveri had no opportunity for deter-
mining the actual sequence of these mesenteries, nor, indeed, does he discuss thcir probable
sequence. llis designation of them may be regarded as a matter of convenience rather than
as indication of their possible ol appearance.

The sequence which I have found for the protocnemes is of great importance, for it is
identical with that characteristic of the majoritj of the Hexactiniae and, in all probability, with
that of the Zoantheae; and it points back to an ancestral stage with eight mesenteries, com-
mon to all these groups, and from which the ( erianthea have branched ofH in one direction
and the Hexactiniae and Zoantheae in another, as 1 have already maintained in previous papers.
It is this ancestral character which gives to the protocnemes their great importance and which
mak' recognition of protocnemes and deuterocnemes fundamental for the proper \m^\-

; the adult Actiniaria.

thors, v.w Beneden and Vanhöffen, however, reached conclusions regarding the
protocnemes of Arachnactis more or less at variance with that described

above. Vanhöffen's observations (1895) were made, however, upon advanced larvae, and his
conclusions were based on the relative lengths of the different mesenteries in these. Little
importance can therefore be assigned to them, for the principle upon which they are based is
manifestly erroneous. Van Beneden (1891), however, foliowed the development of the mesenteries
in larvae of different ages, and, while arriving at conclusions regarding their embryonic sequence
identical with my own, denied that the protocnemes can be regarded as homologous with those
of the Hexactiniae. In proof of this position he makes a comparison between the first six
couples of mesenteries in the two groups, and, designating them in their order, from the ventral
directives dorsally, I — II — III — IV — V + VI, points out that the order of development in the
Actiniaceae is III— V—I— VI— II— IV, while in the Ceriantheae it is II— UI— I— IV— V— VI.
I have already (1893) pointed out the fallacy of such a comparison. It proves nothing to the
point, since it is a comparison between the protocnemes plus two couples of deuterocnemes in
each group, and it is the very basis of the view propounded by Boveri and myself that the
two groups are primarily distinguished by the mode of appearance of the deuterocnemes. If
these be omitted and comparison be made between the protocnemes alone then the sequence
is the same in both groups, namely, III — I — II — IV. Van Beneden, indeed, acknowledges this
identity of succession for the protocnemes, but still maintains that those of the Ceriantharia
cannot be regarded as identical with the so-called "Edwardsia mesenteries" of the Actiniaceae,
since they do not possess the adductor muscles so well developed in those mesenteries, and
the Ceriantharia furthermore possess a well developed ectodermal musculature which is lacking
in the Actiniaceae. Surely these two points must be regarded as of little moment compared
with the order of sequence of the mesenteries, and it must be remembered that Boveri found
indications of adductor muscles, identical in their arrangement with those on the Hexactinian
protocnemes, in the Cerianthid larvas he studied. As to the ectodermal musculature being an
important characteristic it is only necessary to refer to the rapidly increasing number of Acti-
niaceae in which it has been found, our present information on the subject seeming to indicate
that it must be regarded as a primitive Anthozoan character, which has been lost in the
majority of the Actiniaceae and retained in the Ceriantharia.

In his later paper (1898), rich in so many important discoveries, van Beneden adheres
to the position taken seven years before and, while recognizing the existence of two distinct
phases of development in both the Actiniaceae and the Ceriantharia, declines to regard the
first stage as identical in the two groups. In the Actiniaceae he regards the first stage as
terminating with the formation of the sixth couple of mesenteries, while that of the Ceriantharia
terminates with the formation of the third couple; and for this first stage of the Actiniaceae
he suggests the name Halcampula, while for that of the Ceriantheae he employs the name
Cerimila. In making this delimitation of stages it is to be noted that the criterion chosen is
quite different in the two groups. In the Actiniaceae it is the cessation of the appearance of
the mesenteries in couples, while in the Ceriantharia it is an alteration in the order of sequence
of the couples.

With the typical sequence of the Hexactinian protocnemes, under which term I would
include only the first four couples, so well determined, it is a little difficult to understand why

7

van Beneden should draw the line which separates his Cerinula stage from the second phase

of development immediately at th< of the formation of the third couple of mesenterii

A clue is probably to 1»- found in his observation that all mesenteries in the Ceriantharia

makt- their appearance dorsal to the first couple, with the exception of the third couple. This

intern:- mmetrical order of the succession, which. after the appearance of the third

again resumed, and it is the resumption "f tin- symmetrical succession that marks the

inning of the second phase of development. rhe interruption, however, seems to 1" of

s importance than such a view would give it. and further, it may bc noted that the same

symmetrical succession and interruption may be recognized in the development ui the protocnemes

of the Hexactiniae, luit since the deuterocnemes do not form successively in the dorsal inter-

mesenterial chamber it is not so striking as in the Ceriantharia. The men- fact that there is

an interruption to the continued symmetry of succession militates against its acceptance as a

criterion, and the facts that the same sequence exists for the first four Cerianthan couples as

the same Hexactinian couples and ihat an entirely different order of sequence supervenes

with the fifth couple in the two groups seem to point strongly to the recognition of the identity

of the tirst four couples in both groups.

I have in earlier papers taken the position that not two but three stages of development

nized in the Hexactiniae; (i a protocnemic stage in which four couples oi

mesenti re formed, (2) a deuterocnemic stage in which two additional couples appear, one

in each of the lateral interspaces and (3) a zygocnemic stage in which the mesenteries appear

in pairs. The firsl stage I believe to bc common to all the Anthozoa, and to be the only

ited in the Alcyonaria, the deuterocneme stage occurs in the Ceriantharia, Zoantheae

and Actiniaceae, but while it is identical in the Zoanthea- and Actiniaceae it is different in the

riantheae, that group separating from the other two at the conclusion of the first stage.

Finally, the zygocneme stage occurs in the Zoanthea^ and Actiniaceae, but differs in the two

■ups. which separated at its appearance. Duerden's observations indicate that the Rugosa

also possessed three stages, the third again differing from that of the Zoantheae and Actiniaceae,

and from van Beneden's own observations (1898) it would seem that only two stages are

nted in the Antipatharia and that these stages are possibly identical with the corresponding

of the Actini and Zoantheas. This last point can only be settled, however, by a

termination of the order of sequence of the Antipatharian mesenteries.

1 have discussed this question of the homology of the Cerianthan protocnemes at somc

length, because it has an important hearing upon the significance of certain structural peculiarities

which I have noted in the forms represented in the "Siboga" collection. These peculiarities do

not in themselves involve the identity of the protocnemes of the Ceriantharia with those oi

the Hexactiniae, but they do point strongly toward a necessity for a recognition of four couples

nemes in the tonner group. In considering these peculiarities it will be well to review

briefly our knowledge of the arrangement of the mesenteries in the Ceriantharia, but before

■ is necessary to consider the terms of orientation that are to be used.

It has been a general custom to speak of the two extremities of an Anthozoan as oral

and al 1 listal and proximal, and to regard the edges of the plane which passes

8

through the directive endocoels as representing the dorsal and ventral lines. Furthermore, in
cases in which but a single siphonoglyph occurred it has been customary to regard it as occ-
upying a ventral position. On this basis the surface of a Cerianthid occupied by the protocnemes
would be the ventral one, while that at which the formation of new deuterocnemes occurs
would be designated as dorsal.

Objections have been raised against this terminology inasmuch as it implies an arbitrary
homology of the surface at which the single siphonoglyph occurs throughout the entire group
of the Anthozoa, and Carlgren (1893), from his observations on the arrangement of the mus-
culature in the mesenteries of adult Cerianthids, has maintained that in reality the siphonoglyph
(sulcular) surface in these forms is probably equivalent to the sulcular surface of the Alcyonaria,
for instance, and if we term this dorsal, then the protocnemes of the Cerianthids are dorsal
and the deuterocnemes form in the ventral chamber.

In opposition to Carlgren's observations stands Boveri's account of the arrangement
of the musculature in Arachnactis, which shows an orientation of the longitudinal muscle fibres
of the protocnemes with reference to the siphonoglyph identical with that occurring in such
monoglyphic forms as the Zoantheae and Oractis, assuming, as I believe there is every reason
for doing, that the sequence which I have assigned (1891) to the protocnemes of these forms
is correct. But apart from this and disregarding entirely the evidence derivable from the arran-
gement of the musculature, there is the more pertinent evidence derived from the homoloo-v
of the mesenteries as determined by their sequence. If this be accepted as a criterion, and the
sequence of the Cerianthid mesenteries be as I have maintained, it follows that if we regard
the single siphonoglyph of the Zoanthids as ventral we must apply the same designation to
that of the Cerianthids. In what follows, accordingly, I shall employ that orientation and speak
of that surface of the Ceriantheae which is occupied by the protocnemes as ventral and of
that occupied by the deuterocnemes as dorsal l).

The Arrangement of the Mesenteries. The first definite information which we
possess concerning the arrangement of the mesenteries of the Ceriantheae was furnished by
Haime (1854), who observed that in C. »icmbra7iacms the mesenteries were not paired and
were alternately longer and shorter; further, he also noted the occurrence of a couple which
extended the entire length of the body and bounded a groove which he termed "la gouttière
interlamellaire impaire". Von Heider (1879) made an important addition to Haime's obser-
vations by discovering that short sterile mesenteries regularly alternated with the fertile ones,
which were the only ones that Haime had observed, and he further noted the existemce of a
couple of short sterile mesenteries, those which we now call the directives, hing between the
long ones which bounded the gouttière impaire. As a result of these observations he recognized
three grades of mesenteries as occurring in Cerianthus, namely, (1) short sterile mesenteries
which he called Filamentsepta, (2) the longer fertile mesenteries which he termed Genitalsepta,
and (3) the long couple bounding the gouttière impaire which he termed the "continuirliche

1) I do not propose to discuss the use of the terms anterior and posterior suggested by van Beneden as indicating more
correctly the relationship of the Cerianthea: to the metameric animals. The theory upon which the application of these terms rests seems
to me too insecure to warrant so radical a change in our ideas of the tectology of the Anthozoa.

SIEOGA-EXPEDITIE XV tl.

IO

O and R. Hertwig (1879) published an account < » i" tin- arrangement of the mesenteries
which did not differ materially from ihat of Haime, but in ;i postcript, written after the
appearance of von Heider's paper, the) added .1 confirmation <»t" his results.

All these observations wen- made on ( '. memóranaceus, for although the Hertwi
mention ( '. as having been included within the scope of their observations, it would

seem that their anatomical studies were confined to the first named species. In 1890 I showed
th.it in C. amei . while the general plan of the mesenteries was 1 i entially the same as

in ( '. membranaceus , there were differences in the details. Thus I noted, as Haime had done,
that shorter fertile mesenteries alternated with longer ones, and also that short sterile mesenteries
alternated with both series of fertile ones. The short directives and the continuous septa were
served, but these latter wen- not the only mesenteries which reached the aboral pole
of the body, several of the longer fertile ones having a similar length.

In 1891 Faurot, trom his studies on C. memó,ranaceus, brought into prominence an

important characteristic in the arrangement of the mesenteries of that form, namely, that as a

It of the alternation of sterile and fertile mesenteries and of the alternation ol short and

fertile ones, there was in reality an arrangement of the deuterocnemes, at least, in quar-

, or as Fauroi preferred to term them quatrosepta. The mesenteries in the vicinity ol

glyph were found to present an arrangement different from that of the more latei. il

quartettes, and while at first Faurot regarded the four mesenteries on either side of the mid-

ventral line as p-presenting an aberrant qnartette, in his later paper (1895) he places only

the three ventral couples in a group apart and begins the enumeration of the quartettes with

tlv fourth couple. In making this change, which cannot be regarded as a happ) one, Faurot

apparently inlluenced 1>\ the views of van Beneden (1891) concerning the si^niticance of

ianthid protocnemes, and the latter author in his account of the arrangement of the

in C. lloydii (1898) also regards the fourth couple from the mid-ventral line as the

inning of the first quartette.

I have given above what seem to me to be good reasons lor regarding the fourth
couple as belonging to the same series as the more ventral couples; for regarding, in other
words, the four ventral couples as forming a protocnemic group, and all the other couples .1-.
forming a deuterocnemic group. and on this ground alone it seems t<> me preferable to regard
the quartetti beginning with the fifth couple of mesenteries, that is to say, with the first

deuterocnemi quartette arrangement, under such a system of enumeration. would be

characteristic of thi 1 rocnemes, leaving the protocnemes as a group apart.

The Prol mie Mesenteries. The four couples of mesenteries which represent

the protocnemes in tlv adult have a very similar arrangement in those species in which the
arrangement has heen longest known, as, for example, in C. membranaceus (Haime, [854; von
79; Faurot, . C. lloydii van Beneden, 1898) C. verrillii (Kingsley, 19

I , that ihc- term that

vin his papci "ti Vl RRI1

>l the specific name by I ' ■, 1 on

i erlooked the

1 1

and C. americanus (Mc Murrich, 1890). Within recent years, however, a number of forms that
show a distinctly different arrangement of these mesenteries have been described, such as
Pachycerianthus bcnedeni (Roule, 1904), P. oligopodus (Cerfontaine, 1909) and P. cestuari, P.
johnsoni and Botryanthus benedeni (Torrey and Kleeberger, 1 909) v). Since the publication of
von Heider's paper (1879) it has been recognized that the most ventral couple of mesenteries
of C. memèranaceus is characterized by being short, sterile and destitute of mesenterial filaments,
and that the second couple extends to the aboral pole, is fertile and is provided with mesenterial
filaments. The same conditions obtain for the corresponding mesenteries of the other three
species of Cerianthus mentioned above, and to the most ventral couple the term directives
has been applied, while the second couple of mesenteries have been termed the continuous
mesenteries, a term which may be conveniently replaced by telocnemes. The third couple resemble
the directives in being sterile, except, apparently, in C. verrillii, but they are provided with
mesenterial filaments, much coiled in a portion of their course (data with regard to this point
being lacking for C. verrillii); their length varies in the different species, but they are always
considerably shorter than the mesenteries on either side of them. The fourth couple resembles
the telocnemes in being fertile and provided with mesenterial filaments, which, however, do not
show the extensive coiling presented by those of the third couple; considerable variation in
length is shown by these mesenteries in different species, since in C. lloydii and C. verrillii
they are almost as long as the telocnemes, while in C. monbranaceus and C. americanus they
are much shorter, in the former species, however, being longer than any of the cleuterocnemes,
while in the latter they are surpassed by a number of them.

In these four species, therefore, there is a general uniformity in the character of the
protocnemes, which may be expressed in a few words by saying that the telocnemes are the
second couple. In 1904, however, Roule described an arrangement of the mesenteries in a form
which he named Pachycerianthus benedeni, which differs markedly from that just described in
that it is the fourth couple instead of the second which become the telocnemes. He finds that
the mesenteries are nearly all rather short, extending but a short distance beyond the lower
edge of the stomatodaeum, but two of them, which, using van Beneden's nomenclature (1898),
he designates S3 reach the aboral pole, enclosing the gouttière impaire, which contains vestiges
of the mesenteries D and S1, these being the first and second protocnemic couples. No mention
is made in his paper of the third couple of protocnemes, but it is evident that they too must
lie in the gouttière impaire. Such an arrangement is exceedingly interesting and important, and
it was of no little interest to fincl in the "Siboga" collection two species which also showed it.
One of these seems to be identical with the form described by Kwietniewski (1898) as C.

fact that Danielssen first employed the Dame in 1860 and that it was given as a synonym of C. lloydii by Sars in 1S61. Danielssen's
application of the term certainly has the priority and it is Verrill's use of it that must be given up. It is interesting to note that the
term C. danielsseni which Kingsley proposed for C. borealis Dan., was also suggested for that form by Levinsen in 1893, and that the
same name has also been bestowed by Roule upon a species described by him in 1905.

1) These last three species the authors refer to the genus Cerianthus. The arrangement of the protocnemes shows that two of
them must be referred to the same genus as the Pachycerianthus benedeni of Roule (1904). As to the third if we accept the validity of
van Beneden's division of the Cerianthida; into the two groups Acontiferae and Botrucnidifera;, it must be referred to the latter group
and therefore must be separated from Cerianthus. I suggest for it the name Botryanthus, unless it be shown in the future to belong to
one of the genera van Beneden has established for Botrucnidiferous larvae.

I 2

/ '• /VVV $& v >V\.VVV

nd I -h. til refer to it in what follows ;is Pachycerianthus fitnèriatus l), while the

other may be termed /'. monostichus, the
specific term referring ti> the arrangement "f
the labial tentacles which will 1"- described later.
The same arrangemenl is also described by
( i km '\ r \i\i i [909 as occuring in /'. oligopodus.
In /'. fimbriatus^ two individuals of
which proved to l»- in a most admirable con
dition for investigation, the arrangement of the
protocnemes was as follows3). The directive
mesenteries, like those of other species, were
short, sterile and destitute of mesenterial fila-
ments. The second and third couples were but
little longer than the sterile mesenteries of the
deuterocnemic quartettes (see Text-figure II .
which they resembled in being provided with
mesenterial filaments extensivelj coiled in the
lower part of their course. Following von
Heider's classification both couples of me
teries would be referrcd to the group of Fila-
mentsepta, and the only appreciable difference
in the two was that the mesenteries of the
second couple were slightly longer than those
of the third. The fourth couple on the other
hand, was formed l>y two mesenteries which
wen- fertile and provided with mesenterial
filaments that were not extensively coiled, and
they alone of all the mesenteries, both protoc-
nemes and deuterocnemes, reached tlu: aboral
pole. They have. then, all the characters of
telocnemes, hut the)- differ from those of C.
memöranaceus, etc. in being the fourth couple
of protocnemes instead of the second.

1) 1 name given by Kwietnibwski is ch
it had already been emp to,1 foi a

which he oamed ./. linia elongata, but which was probably Cerianthus
eus.

2) The two individuals upon which <hi- description is

in f-. uu. 'lm. and thi ii i onditiou
well .Th lier examples, <>f which there were quile

11 in a mop
rated condition. It was p delermine

in a numbcr of these that the general arran

identical with that of the formalin exampl

In P . monostichus (see Text-figure X), in P. oligopodus and in P. ezstuari, P. Johnsoni
and Botryanttms benedeni the arrangement is essentially the same. On either side of the short,
sterile directives are two sterile mesenteries, both of which are considerably longer than the
directives, though but little longer than the sterile deuterocnemes, those of the second couple
being longer than those of the third. The fourth couple of protocnemes consists of fertile
mesenteries which reach the aboral pole.

In four distinct species, then, the telocnemes are the fourth couple counting from the
mid-ventral line, and this arrangement seems therefore to have more than mere specific value.
If so, the question arises as to whether indications of the two arrangements can be found in
the early stages of development. A study of the various larval forms described so thoroughly
by van Beneden (1898), together with my own observations on some additional ones obtained
by the "Siboga", have led to some interesting results in this connection.

Van Beneden has divided the larvse he studied into two groups characterized by the
appendages which occur on certain of the longer mesenteries. In one group these mesenteries
bear peculiar aggregations of cells which may be set free within the coelenteron and have been
termed botrucnida, while in the other group the appendage is a more or less filamentous
structure which van Beneden has identified as an acontium. The Botrucnidiferse need not con-
cern us here; but in the Acontiferse will be found certain variations in the mesenteries which
bear the acontia, and in correlation with these apparently certain other peculiarities of struc-
ture. Unfortunately the acontia are in some cases a little late in making their appearance, and
some of the larvse obtained do not possess them, but in several of such cases one or more
of the other peculiarities are evident and from these it may be predicted upon what mesenteries
the acontia will appear.

To consider first the acontia. These occur as a rule only on one or two couples ot
mesenteries, the more ventral of which may be either the second or the fourth protocneme.
In Arachnactis albida, in his three species of Ovactis and in Dactylactis armata and D. digitata
van Beneden found the acontia upon the fourth couple and they are also clearly shown on
the fourth couple in Boveri's fig. 3 (1890) although he did not perceive their significance ;
Gravier (1904), found them on the fourth and sixth couples in D. benedeni ; and to this list
I can add Ovactis wilsoni and from the "Siboga" material Arachnactis siboga and Dactylactis
malayensis, all three with the acontia on the fourth couple, so that it would seem fairly certain
that in these three genera, Dactylactis, Arachnactis and Ovactis, the acontia are borne by the
fourth protocnemes. In the species of the three remaining genera described by van Beneden
the acontia had not appeared in the larvae studied, but in the "Siboga" collection I find
representatives of two of these genera, namely Apiactis and Peponactis, and in the species
belonging to the former the acontia are borne by the second protocnemes and in the species
of Peponactis they are present on both the second and fourth protocnemes.

In the more advanced larvse of the first group it is found that in addition to the fourth
couple being the first to possess acontia, the are also the longest of the protocnemes. This is
the case in Arachnactis albida, A. siboga, Ovactis brasiliensis, O. cequatorialis , O. wilsoni,
Dactylactis armata, D. digitata, D. benedeni and D. siboga. Of the other known species of

' t

tl„- tme that in the oldest yel observed the fourth couple is shorter than

the second, but this may justifiably be regarded .is due to the known stages being too young

to show the definite length relations of the mesenteries. The fourth couple is formed later than

th,- ; and must for a time therefore, be shorter than the second in all species, and it ma)

ed that its shortness in the tonus under consideration is .1 condition whicfa will later

,1. in 1 bermudensis we certainly cannot consider the arrangemenl seen in the

oldest know larva .is necessarily representing the aduh relations, and this is equally true for

Da lermis and D. elegans and perhaps also for Solasteractis macropoda in regard i"

which there is yet no information as to the development <>( tin- acontia. It is true that in the

oldest known examp Ovactis brasiliensis described l>y van Beneden the second couple is

still longer than the fourth, hut in the monstrous form of the same species it is noticeable that

one side of the sagittal plane the mesentery of the fourth couple is the longer, and this

being the relative length of the couple in other species of the genus, it may be regarded as

indicating what the adult relations will be.

There are, then, in the protocnemes of quite an extensive series of forms two associated
iliarities which seem to be constant, and are therefore to be regarded as characteis oi
taxonomie importance. Hut before taking up this question further I wish to consider the arran-
nent of the deuteroencmes and certain other structural features ot the order.

The Deuterocnemic Mesenteries. The development of our knowledge of the
arrangement of the deuterocnemic mesenteries has already been described and the important
dis of Faui 91) of the quartette arrangement has been noted. It has also been pointed

out that Faurot in his later paper 1 [895) and \ \n 1!im i>i \ [898 begin the enumeration of the
(|iiariett<-s with the last protocnemes, a method which is inconsistent with the true relationship ot
the two sets of mesenteries. Correctin^ this error, in each of the species hitherto described in which
the quartettes have been sufticiently Studied each is composed of two sterile and two fertile
mesenteries, the sterile and the fertile alternating. In the different species considerable differen>
occur in the relative lengths of the mesenteries composing each quartette, and it seems probable
that these differences may have a classificatory value, although this cannot be definitely determined
until a greater number of individuals of each species has been studied.

B( • illing attention to these differences a few words are necessary as to the

of the quartette mesenteries. Von Heider's terms Filamentsepta and Genitalsepta
are not quite opposite for several reasons, the fact that in one of the species to be described
later the Filamentsepta as well as the Genitalsepta bear reproductive organs being the most
important one. and the same fact makes the use of the terms sterile and fertile also inappropriate.
In what follows I shall term the longer mesenteries (von Heider's Genitalsepta) macrocnemes
and the- shorter ones von Heider's Filamentsepta) brachyenemes.

In C. membranaceus the first quartette, that is to say that nearest the protocnemic group,

f first a brachyeneme, to which succeeds a macrocneme, then a d brachyeneme

horter than the first and then a second macrocneme longer than the first one

111 . [f the brachyenemes be represented by b and B lor the shorter and longer

m< tively and the macrocnemes be similarly represented by m and .1/. the

'4

i5

arrangement of the quartette may be represented by the formula B — m — b — M. The same

formula answers also for the succeeding quartettes, but it will be observed that in each quartette

there is a gradual diminution in the length of each of the four kinds of mesenteries compared

with the corresponding mesentery of the preceeding quartette. In other

words the mesenteries of each kind diminish gradually in length towards

the dorsal mid-line, the length of any one kind being proportional to

that of the preceeding quartette. Hence, as regards their lengths four

different kinds of deuterocnemes may be recognized. Along with this

arrangement is to be noted the fact that none of the deuterocnemes

approach the aboral pole.

In C. verrillii the arrangement of the mesenteries in the
quartettes is essentially the same as in C. membranaceus, being expressed
by the formula B — m — b — M, and the same correlation in length of
the individual mesenteries of each set also occurs. A differance is
found, however, in the fact that three of the longer macrocnemes on
each side extend almost to the aboral pole and there is a gradual
diminution of the remainder of this set towards the dorsal mid-line
(See Kingsley, 1904).

In P . fimbriatus (See Text-figure II, p. 1 2) the arrangement
is similar to that of C. membranaceus, although in the single example
carefully examined the regular diminution in length of the various
kinds of mesenteries was interrupted in the third, fourth, fifth and
sixth quartettes, but resumed in the succeeding ones. None of the
deuterocnemes approach the aboral pole.

In P. monostichus, so far as I was able to ascertain the arrangement, it was similar to
that of C. verrillii, but an account of the details of the arrangement both in this form and in
the preceeding one will be given later with the description of the species (See Text-figure X).

In these four species, then, the arrangement of the quartettes was according to the
formula B — m — b — M. In the two species now to be mentioned we find a different formula is
necessary, namely, B — M- — b — m ; that is to say, the longer macrocneme precedes the shorter
one in each quartette. This is the case in C. lloydii (Van Beneden, 1898), and in this form
we find that while the two sets of brachyenemes have an independently progressing length-
diminution towards the dorsal surface, the two sets of macrocnemes form one diminishing series,
the shorter macrocneme of the first quartette being longer than the longer one of the second
quartette and so on. Furthermore, the macrocnemes of the first two quartettes extend to the
neighbourhood of the aboral pole, but with the third quartette a sudden diminution in length
comes in, none of the mesenteries from this one extending beyond the middle of the column.

In C. americaims (Mc Murrich, 1890; see also Text-figure IV) the quartette arrangement
is also B — M — b — ;//. The brachyenemes are all very short, extending but a short distance
below the lower border of the stomatodaeum, so that the amount of difference in length of
those of each quartette is relatively small though appreciable, and, as a rule, the longer one

15

Fig. III.

Diagram showing the arrangement

of the mesenteries of

Cerianthus membranaceus.

Adapted from Faurot.

was ih.it nearer the ventral line. Similarly, owing ti> the shortness of these mesenteries their
idual diminution in successive quartettes was not very pronounced.

\ 'k the macrocnemes, there is a great disparity in the lengths ol the shorter

and longer ones, the former extending bul a
short distance below the lower border of the
stomatodaeum, while the latter reach at l<
as far as the middle of the column, some oi
them almost to the aboral pole. Nor is the
ventro-dorsal diminution of the longer macro
cnemes a constant one. In four individuals
examined the longer macrocneme of the first
< jnartette reached a little beyond the middle
of the column, that of the second quartette
almost to the aboral pole, that of the third
to about the lower fifth of the column, and
that of the fourth almost to the aboral pole.
Beyond this some variation occurred, the lo
mesenteries of the fifth and sixth quartettes
reaching to beyond the middle of the column,
that of the sixth being usually, but not always,
slightly the longer of the two, and then foliowed
sometimes one, and sometimes two quartettes
in which the mesenteries under consideration
almost reached the aboral pole, and in the
remaining three or tour quartettes they rapidly
diminished in length.

In all the forms hitherto described the

alternation of sterile and fertile mesenteries is

characteristic of the quartettes, but in a form

found in the "Siboera" collection and which I

identify with C. ambonensis this was not the

-e, all the mesenteries. both protocnemes

and deuterocnemes, being fertile with the exception of the directive couple. A detailed account

of this form will be given later on and it need merely be stated here that the deuterocnemes

were arranged in two alternating the brachycnemes extending only to about 3 cm. below

the lower border of the stomatodaeum, while the macrocnemes were continued onwards for

5 cm., reaching to within 2 cm., of the aboral pole, the telocnemes, which are the

eing the only mesenteries to reach that pole. Whether slight variations in length

of ti rocneme each, or even of successive quartettes, wen- always presenl I was unable

the arrangement of the deuterocnemes appearing to be in duettes rather than in

quarti tl figure V, p. 2

16

IV.
g the arrangement of the mesenteries of

1/

The Arrangement of the Tentacles. Since Fischer discovered (1889) in C.
membranaceus the existence of an unpaired tentacle corresponding to the ventral siphonoglyph,
various attempts have been made to formulate a definite arrangement for the marginal and
labial tentacles. Although in their details these attempts have produced somewhat discordant
results, vet they have shown that the tentacles of the Cerianthids cannot be regarded as being
arranged in cycles comparable to those of the Actiniaceae; that, however, cycles of another
type can be made out; that the corresponding tentacles of the marginal and labial sets do
not necessarily belong to corresponding cycles; and that the tentacles of the various quartette
groups are, in general, defmitely and similarly arranged with regard to the cycles.

One of the discrepancies noticeable in the different observations is the number of cycles
recognized. Thus, Fischer (1889) recognizes but three, while Cerfontaine (1891), Faurot (1895)
and Carlgren (1900) admit four in each set, and van Beneden (1898) recognizes in C. lloydii
three in the marginal and four in the labial set. The difference is, however, of comparatively
little importance, since the two outer cycles are somewhat crowded together and differences of
contraction will readily lead to confusion of the two. In the examples of P. fimbriatus which
I have studied there are four cycles in each set, but here and there, at different portions of
the circumference, it is difhcult to determine whether a tentacle belongs to the third or the
fourth cycle, especially in the case of the marginal set.

The differences observed in the arrangement of the tentacles in the various cycles are
of greater importance. The arrangement which Faurot (1895) figures for the marginal tentacles
of C. incmbraiiacetLS may be represented thus:

— 1 | 4, 2, 3, 1 | 4, 2, 3, 1 |J 3, 4, 1, 4, 3 |j 1, 3, 2, 4 | 1, 3, 2, 4 | 1 -,
a formula which represents the protocnemic tentacles and two quartettes on either side, and
which may better be represented thus; recognizing the fourth tentacle from the mid-ventral
line as belonging to the protocnemic set;

— 1, 4, 2, 3 | 1, 4, 2, 3 || 1, 3, 4, 1, 4, 3, 1 ;| 3, 2, 4, 1 | 3, 2, 4, 1 -.
Earlier, however, Cerfontaine (1891) had found the arrangement to be as follows :

'i ji -i 4 I 'i ji J'4 li ji 4i -1 4i 01 ' | 4i -1 Ji L | <+> -1 01 l 1

the difference arising from a confusion of the third and fourth cycles in the quartette tentacles
and of the first and second in the protocnemic ones. Carlgren (1900) confirmed Cerfontaine's
results and found the same arrangement in C. lloydii, in which form van Beneden (1898) had
described the arrangement as

3i 2> j> ' | 3' 2i ji l | 2> o> 2i 01 - 'iji-i j | xi ji -1 3
which may be better expressed thus :

1 1 Ji -i J I l ! 0> -1 0 | 'i -1 Ji -1 Ji -1 ' | J) 'i Ji ' | J) -1 J' *

The difference is explicable, so far as the quartette tentacles are concerned by the fact that
van Beneden recognized only three cycles in the marginal set of tentacles; there is, however,
a discrepancy in the arrangement of the protocnemic tentacles. In C. solitarius Carlgren found
the same arrangement as in the other forms, although the third and fourth cycles are less
clearly distinguishable and irregularities, due to the failure of tentacles to develope, occur.

17

SIBOGA-EXrEDITIE XV a. 3

i8

A-> regards the labial tentacles, Fauroi finds in ('. membranaceus an arrangement which
inay be expressed thus:

2, i. 3, i 2, i, 2, i 2, i,4, 2 i, 3- \, 3, 4, 3, i 2, 4, 1, 2 | 1, 2, 1, 2 .(, 3. 1,2 —
while Cari gri n finds

, 1,3,4 2. 3. 2, 4 3. i.3i 2>3i 1» 3 4,2,3,2 4,3,1,2—.
\'\n Beneden gives an arrangement for C. lloydii which maj \«- expressed by

2,1,3,4 2.3,1,4 4,2,3,0,3,2,4 4, 1, 3, 2 | 4, 3, 1, 2 — ,
while Carlgren finds in the same species

■» 1 ■• i I *> ■» "> 1 2 "» 1 { ) 1 1 1 I 2 2 2 I A 2 T 2

In (. Carlefren finds the same arrangement as in C. membranaceus.

In looking over these results it seems clear that there is a general similarity and the
diffi ■ are probably largely due to the difficulty of correctly following the lines ofthevarious

and avoiding the danger of being deceived by differences of contraction.

In /'. Hmbriatus the arrangement I found to be

1, 3, 2. 4 | 1. 3, 2. 4 i, 3, 4. 2, 4. 3, 1 4, 2, 3, 1 j 4, 2, 3, 1 -,
although it must be said that a distinction between the fourth and third cycles was not always
discernible. For the labial tentacles 1 obtained the formula

> 1 1 a > 1 2 A 2I121I2A212AÏI2 .

The arrangement of the marginal tentacles is, therefore, identical witli what Carlgren found
in C. membranaceus, C. lloydii and C. solitarius, but I find a difference in the arrangement
of the labial tentacles, a difference which may. however be due rather to the difficulties ot the
determination and to the small number of examples (2) suitable for examination.

In other forms, however, decided departures from tliis arrangement occur. Thus in C.
iaeda the marginal tentacles seem to be arranged in only two cycles, their formula being

2I2ll2I2I 2 I 2 I 2 I 2 [21 21 2 1.2

while the labials are on a quadricyclic plan, their formula being

1.2,4,3 1.2,4,3 1,3,4,2,4,3,1 3.4,2,1(3,4.2,1—.
In C. monostichus the marginal tentacles, so far as could be determined, seemed to have the
same formula as C. taedus, but, on the other hand, the labials were in a single row.

In nu larval forms has an arrangement of the ifiitacles in multiple cycles been observed,

all, both marginal and labial, lying in a single cycle. The multicyclical arrangement of the adult

may be due to merely mechanica! causes, as was suggested by von Heider. This explanation,

lic/ by itself hardly sul >r the regularity of the arrangement recurring in the various

quartette groups, and the possibility of some additional factor imposed by the arrangement of

mesenteries suggests itself. From what is seen in larval forms it is evident that the formation

of new mesenteries always precedes that of new tentacles, and, consequently, the tentacles

ding to any mesentery is that communicating with the intermesenterial chamber nexl

it. An examination of the marginal tentacles of the quartettes wil! show that the

proximal cycles are those corresponding to the macrocnemes, while those

iS

19

of the two distal cycles correspond to the brachycnemes. The marginal tentacles correspondino-
to the protocnemes and the labials do not, however, present this relation, and its value as
a determining factor must therefore remain uncertain.

The Mesenterial Filaments. The structure of the mesenterial filaments of the
Cerianthese has been considered by von Heider (1879), the Hertwigs (1879) and van Beneden
(1898). Von Heider noted the occurrence in C. membranaceus of a thickened border to the
mesenteries, and observed, too, that the thickening extended to a much lower level upon the
fertile mesenteries than upon the sterile ones, the edge of the mesentery below this thickening
being occupied by a much smaller swelling. Furthermore he observed that toward its extremity
the upper larger thickening on the sterile mesenteries became much contorted and gave off
numerous branch filaments, which he identified with acontia. Similar branch filaments, though
less numerous, were observed also on the fertile mesenteries and they were found to occur
scattered along almost the entire length of the telocnemes.

The Hertwigs added to von Heider's description a much more accurate account of
the finer structure of the filaments. They figure on PI. VIII, fig. 12 of their paper the upper
portion of a mesentery, showing the upper portion of the filament but slightly wavy and bearing
numerous slender, branched processes, this portion being succeeded by a stretch in which the
filament is greatly coiled. Below this the filament is described as running in a wavy course to
the end of the mesentery. In its upper part the filament is shown to consist of three clearly
differentiated portions, a median " Nesseldrüsenstreif " and two lateral "Flimmerstreifen", its
structure, therefore being exactly comparable to that of the upper trefoil portion of the Actiniacean
filament. The processes arising from the filament were shown, however, to be very different in
structure from the Actiniacean acontia, being extremely attenuated folds of the filament, possessing
"Flimmerstreifen" as well as "Nesseldrüsenstreifen" and of each of these an ascendine as well
as a descending limb.

Van Beneden confirmed the Hertwigs' observations as to the trefoil structure of the
upper portion of the filament and also von Heider's account of the greater extent of the trefoil
in the fertile than in the sterile mesenteries ; he noted too that the greatly coiled portion of
the filament occurred only on the sterile mesenteries and that the filament in this portion of
its course was no longer a trefoil, but simple. His most important addition to our knowledge
of the filaments was the discovery of true acontia in larval forms, arising from the free edge
of one or more of the fertile mesenteries, usually some distance below the termination of the
mesenterial filament and resembling closely in their structure the acontia of the Actiniaceae.
This discovery completed the proof of the distinctness of the branching processes of the trefoil
portion of the filaments and the acontia, and it consequently seems advisable that we should
now have a term to distinguish the processes. The Hertwigs, it is true, named them "Mesen-
terialfaden", but this term is a little too similar to mesenterial filament to prevent confusion,
and it would seem both convenient and apposite to translate the term and to speak of the
processes as craspedonemes.

Owing to the excellent preservation of some of the examples of P. fimbriatus in the
present collection it has been possible to make a thorough study of the structure and arrange-

19

21 i

ment '<t' the mesenterial filaments of th.it form, and .1 record of the results, combfned with
some observations on the filaments of C. americanus, seems advisable for the purpose ol
rounding out our present information concerning the mesenterial filaments of the Ceriantheae,

In both the forms mentioned all the mesenteries, with the exception of the directivi

provided with mesenterial filaments, and all of these possess the same histological structure.

Vs in the filaments of the Actiniaceae, two portions are recognizable in each filament, an upper

trilobed |>i.rtioii and a lower simpler portion, but in the Ceriantheae marked differences in the

iment of the two portions are shown by the macrocnemes and brachyenemes.

In the latter the uppermöst portion immediately succeeding the lower border of the stomato-

an lias an almost straight free border, and throughout this stretch the filament is trilobed.

> portion is succeeded l>v a stretch in which the border is much folded and apparently

branched, and throughout which the filament is single-lobed (this portion is represented as

wavy in text-figure II, p. [2); and below this again, the free edge is almost straight and the

single-lobed portion of the filament is continued along it almost to its termination, only the

terminal portion of the mesentery being destitute of a filament.

In the macrocnemes, on the other hand, the trilobed portion of the filament extends a
much greater distance down the mesentery, as shown by the cross marks in text-figure II. the
single-lobed portion being limited to its terminal part, which is almost straight and in no case
thrown into the complicated folds and branchings seen in the brachyenemes.

The filament throughout its trilobed portion, except in its uppermöst part, may give
rise to craspedonemes, but considerable differences occur in the different species in the extent
of the development and distribution of these structures. In C. memèranaceus and C. americanus
they occur in considerable numbers and in the form of long slender threads upon the edges
of the mesenteries a short distance below the lower border of the stomatodaïum, and are quite
conspicuous in individuals of these species opened under water so that the craspedonemes may
float freely. In /'. fimöriatusy on the other hand, they are quite inconspicuous, being few in
number and having the form of comparatively short digitiform processes rather than elongated
threads. but they are to be found at intervals along the entire length of the trilobed portion
of the filaments of the macrocnemes, a condition which does not obtain in C. americanus,
although apparently present in C. memèranaceus.

The minuter structure of the filaments of /'. fimbriatus in the trilobed portion is as
follows. The mesogloea of the edge of the mesentery is enlarged into a somewhat quadrate
mass (PI. I. I ig. 12 . whose distal angles are produced into slender processes projecting at right
angles to the plane of the mesentery. while the proximal angles are prolonged into stouter
recurved | ». ( >ver this <pi.idi-.ite mass the epithelium is arranged, and il is differentiated

into five distinct areas, tour of which are paired, while the fifth, which lines the distal face oi
the quadrate thickening of mesogloea, is unpaired. There can be recognized, therefore, in this
on of the filament a median streak, two distal lateral and two proximal lateral streaks.

The median streak Fig. 1 2 M ■ is composed principally of narrow elongated cells, whose

nu ■ long and narrow. are lo all at about the same level near the distal ends ol the

uticle lines the free surfaces of the reik. which are provided with strong cilia.

2 I

Amongst the cells are a few scattered, elongated gland cells, which stand out very prominently
in haematoxylin preparations owing to their contents taking the stain very deeply. No nematocysts
occur in this portion of the filament, but in its lower layer, and resting upon the mesogloea, are
a few muscle fibres, over which are indistinct indications of what is, presumeably, a nerve layer.

On either side of this median streak is a distal lateral streak {DL), whose cells are
somewhat longer than those of the median streak, so that the latter occupies the floor of a
rounded groove betvveen the two distal lateral streaks. A close examination shows marked
differences in the histological characters of these streaks compared with what was found in the
median streak. Thus one notices that there is no distinct layer of cilia on the free surfaces of
the streaks and no well-marked cuticular layer-, the gland cells are very much more numerous
and nematocysts are abundant. The cells of these streaks rest upon the prolongation of the distal
angles of the mesogloeal enlargements and no muscle cells could be found in their lower layers.

Finally, resting on the lateral surfaces of the mesogloeal enlargement and on the lateral
faces of the distal and proximal prolongations of its angles are the proximal lateral streaks {PP),
which are composed entirely of slender cells, whose nuclei are near the free surface and which
bear strong cilia. The cells which immediately succeed the distal lateral streaks are as high as
these, but they gradually diminish in height as they are traced proximally, until those lining
the proximal angular processes of the mesogloeal enlargement are very much lower. In conse-
quence of this the streaks have a U-shaped form in section, the rounded lower portion of the
U resting on the lateral surface of the mesogloeal enlargement, while the uprights rest upon
the distal and proximal angular processes. No glands, nematocysts, or muscle cells occur in
these streaks.

It is to be noticed that the endoderm of the mesentery immediately adjoining the proximal
lateral streaks is composed of an epithelium whose scattered spherical nuclei are situated near
the free surface, the basal portion being clear and having a somewhat reticular appearance.

In C. americanus the structure of the corresponding portions of the filaments is essentially
the same, the only differences to be observed being a greater breadth of the median streak,
a slightly better development of its muscle cells and a more spherical or oval form tor its
nuclei and those of the proximal lateral streaks.

With regard to the structure of the craspedonemes, it is clear that they are really folds
of the edge of the mesentery over which the filament passes, so that an ascending ancl a
descending portion of it may be recognized as the Hertwigs pointed out. In P . fimbriatus
they are in all cases comparatively broad ancl low, so that the ascending and descending limbs
are separated by a rather broad band of endoderm (fig. 1 3). The proximal lateral streaks are
always well defined in them, but some difference is to be found in the structure of the distal
streaks as the region where the trilobed portion of the filament passes over into the simple
portion is approached. In a section of a craspodoneme of a macrocneme, in which the trilobed
portion of the filament extends almost the entire length of the mesentery, the structure ot
the limbs is exactly the same as in the filament proper, a median and two pairs of lateral
streaks being clearly discernible. But if a section be taken of a craspodoneme from one of the
brachycnemes, in which they occur only immediately above the region where the single-lobed

21

portion of the filament begins, or it ii be taken from mar the terminal portion of a macrocneme,
it will be found tli.it the median streak has become very much reduced in size or may be
quite absent tli.it the «listal portion of the filament is simple instead <>t" bilobed

and its entire epithelium lias the character of the .listal lateral streaks.

In C is lias been stated, bunches of craspedonemes occur on the brachyc-

nemes just the simple portion of the filament begins. Sections of these show

dy the same structure as the broader and shorter craspedonemes of /'. fimóriatus found

in the same regions, except that the endoderm separating the ascending and descending limbs

much reduced in size, so that the entire craspedoneme lias a quadrilateral appearance

i don (fig. i 4).

In the simple portion of the filament (fig. [5J the structure of the epithelium is very
siniilar to that of the .listal lateral lobes of the trilobed portion. It contains numerous nematocyst
and gland cells, justifying the term Nesseldrüsenstreif generally applied to the corresponding
structure in the Actiniacea. No muscle fibres could be distinguished in the deeper layers ot the
epithelium. although a linely granular structure immediately above the mesogloea probably
represents nerve fihres.

The distribution of the acontia has already been described, and concerning their structure
1 have nothing to add to what has heen given by van Beneden (1898). I have not been able
ti) find them in the adult individuals examined.

It may not be a safe procedure to attempt to deduce from the conditions in the adult
the origin of the different portions of the mesenterial filaments. The HERTWIGS and VON Heider
have come to diametrically opposite results by this method of study, the former maintaining
that the filaments of the Cerianthids are of endodermal origin, while the latter regarded them
.1- downgrowths of the stomatodaeal ectoderm. The relations of the filaments to the stomatodaeal
ectoderm which I have observed in P. fimöriatus and C. americanus are so definite as to point
strongly to the origin of the upper trilobed portion from the stomatodaeal ectoderm as vox
Heider supposed, hut the evidence regarding the lower single-lobed portion is very imperfect
and I do not propose to consider this portion in what follows.

A transverse section through the stomatodamm shows that the mesenteries are attached

to that structure in such a way as to alternate with the longitudinal ridges which traverse it.

An examination of the stomatodaeal ectoderm near its lower hortier will show that there are

decided differences between the epithelium covering the ridges and that lining the depressions

•en them. At the summits of the ridges the gland cells and nematocysts are exceedingly

abundant, while upon their sides and in the intervening valleys both these elements are few in

number and a distinct cuticle and strong cilia are present. In other words, in their histological

structure the summits of the ridges agree with the distal lateral streaks ot" the trilobed portion

-f the filaments, while the epithelium of the sides of the ridges and of the valleys is closely

similar to that found in the proximal lateral streaks of the filaments. If any dependeiice is to

'1 on histological structure in such a case, it would seem that the distal and proximal

aks of the trilobed portion of the filaments are of ectodermal origin, hut as to the

natun- of the median streak my preparations give no definite information.

C lassifica ti o n. Until 1898 no attempt was made to divide the order Ceriantheae
into other than generic groups, but in that year van Beneden recognized two suborders in the
larvae he described, the Botrucnidiferae and the Acontiferae. The Acontiferae are characterized
by the marginal tentacles appearing in the same order as the intermesenterial chambers with
which they communicate, the unpaired median tentacle, however, always appearing later than
the next adjacent couple; certain of the mesenteries bear acontia but never botrucnidre. In the
Botrucnidiferae, on the other hand, the order of succession of the marginal tentacles, after the
appearance of the first three couples, does not correspond with that of the mesenterial chambers,
but they appear on either side in alternate chambers, the intervening chambers developing
their tentacles only later, probably simultaneously with the appearance of the median tentacle;
none of the mesenteries bear acontia, but a greater or less number of thetn are provided with
botrucnidae. These characters seem to definitely limit two groups.

In my discussion of the arrangement of the mesenteries of the Ceriantheae (p. 9 et seq.)
I have shown that in the forms with which we are at present familiar two principal types are
recognizable. In one of these the telocnemes are formed from the second couple of protocnemes
and in the other they are formed from the fourth couple. This seems to be a difference of
considerable importance, and on the strength of it I would recognize in the Ceriantheae two
families, in one of which, the family Cerianthidcr, the telocnemes are the second couple from
the mid-ventral line, while in the other, for which the term Arachnactida may be employed,
the telocnemes are the fourth couple.

We have then two sets of characters which seem to be of oreater than generic
importance and the question arises as to what relation, systematically, they bear to one
another. The question is at present a very difhcult one to answer. An examination of the
known larval Botrucnidiferae seems to indicate that in some members of the group the second,
in others the fourth protocnemes form the telocnemes, just as is the case in the Acontiferae.
Thus, in Calpanthula guineensis it would seem that the telocnemes were to be formed from
the second protocnemes, while in Hensenanthula dactylifera and H. melo it is probable that
they are formed from the fourth protocnemes. What may be the fmal result in Cerianthula
mediterranen, and H. spinifer is less certain ; in the larvae studied the second protocnemes
were the longest, but this condition may be corrected in older stages, the known larvae of
both species being in a much earlier stage of development than those of the other forms. In
the only adult form known to be botrucnidiferous Botryanthus benedeni (Torrey and Kleeberger,
1909), the telocnemes were formeel by the fourth protocnemes.

Accepting this conclusion, if van Beneden's groups be regarded as the more inclusive,
both arrangements of the telocnemes will be found in each group, and, conversely, if the
telocnemic conditions be taken to represent the larger division, then included in each of these
divisions there will be both acontiferous and botrucnidiferous forms. This is not inherently
impossible, but it is a difhcult matter to decide which is the more primitive character. The
occurrence of botrucnidae is associated with an alternating development of the deuterocnemic
tentacles and that of acontia with their successive development. Van Beneden's groups, having
thus two associated characters, seem to have the claim to the higher rank.

h must be recognized, further, as indicating the importance of the botrucnidae as a
classificatory factor, that th<-ir distribution differs markedly from that of the acontia. While, so
t'ar as is known, acontia occur only on the second and fourth protocnemes and on the second
deuterocnemes, and, furthermore, only on two ol these mesenteries at the most, i. <•. on either
the second and fourth protocnemes or on the fourth protocnemes and the second deuterocnemes
the distribution of the botrucnidse is much more extensive. Ihus in Cerianthula
i and Calpanthula guineensis they occur on th<- second, third and fourth proto-
cnemes; in Hensenanthula spinifer and //. melo on th<- same three protocnemes and on a
.:n number of deuterocnemes as well, the first in the one case and the first, second and
third in the other; and in //. <lactylifera they occur on the third protocneme and on the lirst
;d and third deuterocnemes1). Finally in Botryantkus benedeni they are stated t<> occur
on all th<- brachycnemic mesenteries and to be limited to these. The mosl striking feature of
this distribution is the occurrence of botrucnidse on the third protocneme in all the larval forms
and on brachycnemic mesenteries in both larval forms and Botryanthus, mesenteries upon which
acontia have never yet heen observed.

In view of these facts, and until a fuller knowledge of adult forms is available it seems
more convenient to assign the higher rank to van Beni di n's groups and to recognize in the
Ceriantheae two suborders, the Acontiferae and the Botrucnidifera;. The latter will contain the
genera Cerianthula, Hensenanthula, Calpanthula and Botryanthus, while the former may agajn
be divided into the two families mentioned above, the Cerianthidae containimr the genera
Cerianthus, Apiactis, Solasteractis -) and Peponactis, and the Arachnactidae containing the genera
Arachnactis, Pachycerianthus, Dactylactis and < )vactis.

No Botrucnidiferae occur in the present collection.

Suborder ACONTIFERjE van Beneden.

Ceriantheae in which the second or fourth protocnemes, or in some cases both these mesent-
ar<- provided with acontia at least during the early stages of development. The deuterocnemic
marginal tentacles appear in the same order as the mesenteries to which they correspond.

Family Cerianthid e.

Acontiferae in which the second couple of protocnemes are the telocnemes. The succeeding
protocnemes are represented by a brachycnemic couple, usually sterile, and by a macrocnemic
couple. Acontia are borne in larval stages upon the telocnemes and in some cases also upon
the macrocnemic protocnemes.

i) Tliis marked dilTerencc in the distribution of the botrucnidse in //. dactyliftra from what obtains in the other two species
i>ility that it mif;ht be well t ■ » regard spinifer and melo as representatives of -\ liUtinct genus.

that the form of the tentac^ of da< renl ir whal is shown for the other two spi

Ihe ac mtia has nol yel Ijeen determin ictis, which K known only fr.im a single

i oot dcveloped. The genus may eventually require transference to the nunily Arachnactidse.

24

Genus Cerianthus Delle Chiaje.

Synonomy: Tubularia Spallanzani, 1784; Gmelin, 1788; Rapp, 1829.
Actinia (pars), Renier, 1804.
Moscata Renier, 1S28.
Moschata De Blainville, 1830.
Cercus (pars), Ilmoni, 1830.
Cerianthus Della Chiaje, 1830.
Saccantlius (p.p.), Milne-Edwards, 1857.
Bathyanthus (p.p.), Andres, 1883.
Dianthea (juv.), Busch, 185 1.

Acontiferae living imbedded in mud or sand and provided with a sheath consisting of
felted nematocysts and mucus; mesenteries and tentacles usually numerous, so that the quartette
arrangement of the deuterocnemes is distinct. Type Cerianthus membranaceus (Gmelin) 1788.

It is difficult in the present state of our knowledge to give a satisfactory definition of
the genus Cerianthus. The majority of the forms which have been referred to it have been so
imperfectly studied that it is impossible to teil whether they really present the structural charac-
teristics of the Acontiferae or even of the family Cerianthidae, while the characters of those that
have been thoroughly described are rather of specific than generic value, except where they
are of ordinal or family importance. Some of the forms show decided departures from the type
species in the number of mesenteries, the number and arrangement of the tentacles and the
distribution of the gonads, but until a much larger number of forms has been carefully studied
as to their structural peculiarities the proper limitations of the genus must remain undetermined.
Practically the only generic characters at present available are the mode of life and the occurrence
of the sheath, characters which can hardly be regarded as sufficiënt for the delimitation of the
genus, although they serve to separate it from the other genera of the family which at present
are known only in larval stages. It is probable that further observations will necessitate the
recognition of a number of distinct genera, all of which will present the cecological characters
of Cerianthus, but will difter in structure.

As to the synonomy of the genus, it is a question whether the time honoured and
appropriate name of Cerianthus should not be replaced by Moschata. The type species, C.
membranaceus, was first recognized by Spallanzani (1784), who somewhat doubtfully referred
it to the genus Tubularia. Gmelin (1788) first assigned to it a specific name, termining it
Tubularia membranacea, ancl Rapp (1829) attributed his species solitaria to the same genus.
In 1804 Renier1) redescribed C. membranaceus as Actinia cylindrica, and again in 1807 as
Actinia vestita. Stil! later, in 1828, the same author bestowed another name upon the species,
terming it Moscata rododattila but this, on account of its form, cannot be taken as establishing
the generic name. In the latinized form Moschata, however, it was accepted by de Blainville
in 1830. The possible of Moschata has been however, entirely overlooked, the name Cerianthus,

1) I have not been able to consult the various original memoivs of Renier. The statements here made concerning their contents
are based upon the edition of his works published in 1847 by Meneghini (Renieri, S.A., Osservazioni postume di zoologica adriatica,
per cura di Meneghini. Venezia. 1847).

25

SIROGA-EXPEDITIE XV a. 4

26

proposed li\ 1 >i 1 1 \ Chiaji in 1830 ') being universallj adopted. If this date for Deli \ CmAjE's
genus b( 1. then both it and Moschata belong to the same year, and in the absence ol

information as to which reallj had priority, it seems advisable to retain the name which lias
nerally employi
Regarding the remaining synonyms littl<- need be said. Ilmoni's reference of liis Cereus
cuéreus t<> Ok ' ereus is evidently erroneous, tint genus being founded upon the

form now known .is c". pedunculatus, and Forbes' reference of his vestita to Edwardsia is also
an error. Mum ëdwards' Saccanthus, characterized by the absence of a terminal pore and by
: teries being all nearly of equal length, although accepted by Andres (1883) is too

imperfectly described u> be retained, especially as its definition does not sumce to distinguish it
from Cerianthus. Bathyanthus, erected by Andres (1882) for Moseley's C. bathymetricus{\^-jj\
may be a good genus, possibly equivalent to and therefore supplanting Roule's Pachycerianthus,
hut Moseley's description of the single individual examined is too incomplete for certainty.
Finally, it seems tolerably certain that Busch's Diantkea nobilis (1851) is the larval form ol
l 'eriantkus membranaceus.

1. Cerianthus ambonensis Kwietniewski.

Synonym: Cerianthus ambonensis Kwietniewski, 1898.

Stat. [81. Amboina anchorage, reef. 1 ex.

Stat. 213. Saleyer anchorage, reef. 1 ex.

General Form. - The column (PI. I, fig. 1 ), after preservation in alcohol, is stout,
the broadest part being about 2.5 cm. from the margin, whence it tapers gradually towards

1 A greal deal of confusion occurs in the literature as to ihc date of the establishment of this term. Haimi 1854 mentions

as reference^ !•• i: hult CHIAJE's liever, e notom. degli animali invert. Sic. cit. 1S4I and also the same author's Mem. sulla Storia e

1 degli animali sen?a vert. del regno di Napoli (1829 . 1 \GASSIZ in his Nomenclatoi Zoologicus (1842) does not mention it

although he givc-^ Mosi HATA. MlLNE-EDWARDS (1S57J refers it to Della CHIAJE's work of 1S41. and it i> SO • S> 1 DDER ui his

1882). Von Heider refers il to Deli \ 1 hiaji Neapolitan work but gives the date 182S. and Ani

tblishment to Della Chiaje's Instituzioni d'Anat. comp. 1832. hut refers the species ('. cornucopia to the work on the Neapolitan

inver '-i"g 1 110 date for this as 1S30. 1 \< 1 1 1895) gh i

Th' I I have heen ahle t<> tracé them, are as follows. DELI \ CHIAJE's Memorie sulla st.iria e notomia

rertebre del re: ■ ->li was published as four volumes of lext and one volume of plates. The text-volumes

1823 iSjS. hut mme of them contains any descript mention nthus. The name first appears .1:

1 the species figured thereon, it being named Cerianthus cornucopia, the same name
l'late 103. Neither of these Plates is described in the text. the last plate refened to in
establishment of the genus Cerianthus rcst>, Iherefore, on the date of publication
of the volume of plates bears tin- date 1S22. bul there ure reasons for douhting that this represents the date-
of publication of Plmti insiderable variation in the number of plates contained in different copies of the volume, some
the number described in the text volumes, while others contain 74. 8g, or 100. Ii seems probable that Dei.1 \
the publication of a lifth volume of tex! in which the forms figured on Plates 70 — 109 would have heen described,
hut this volume and the inference is that the publishers, in the later issues of the plate volume bound in some or
all of the prcviously unpublished plates, which, a-, may he concluded from the date of ihe plate volume (1822), had heen printed before
tcxt-volumc. It becomes a matter of interest there! ertain the date of issue of tin

the titlc-pagc being insufficiënt evidence. The only evidence I have heen ai tin on this

ipplied by l'r. I . SCHO that in the copy of the work in the library of the

• in l'late 70 to l'late 100 date 1830. It on the evidence availablc,

and 103. an<l, accordingly, the date of the establishment of the genus Cerianthus.
It ■ Plate ta and Zoantht, 1 1830 may therefore be

26

27

the aboral pole. Below the margin about 1.25 cm. there is a marked constriction, above which
are a number of distinct longitudinal furrows extending to the margin and giving the upper
part of the column a distinctly striated appearance. Elsewhere the column is smooth, except
for irregular wrinkles, evidently due to contraction.

The marginal tentacles were numerous, numbering considerably over one hundred, and
were apparently arranged in three cycles. They were almost half the length of the column and
were for the most part strong, stout struetures, tapering rather suddenly toward the tips, although
many were slender throughout so that they might well be described as filiform. The labial
tentacles were also numerous, probably the same number as the marginals, but were more
slender and much shorter, hardly projecting beyond the margin of the concave disk. The dense
crowding of the tentacles and the poor state of preservation prevented a determination of the
arrangement of either the marginal or the labial set, nor was it possible to determine the
presence or absence of the unpaired labial tentacle.

Dim en si ons. — Length of the column, 11 cm.; greatest diameter, 3.5 cm. Length
of the marginal tentacles, about 5 cm.; diameter just above their insertion 3.5 — 4.0 mm. Length
of the labial tentacles, about 2.0 cm.; diameter just above their insertion 1.0 — 1.5 mm.

Colour. — The column is throughout its entire extent of the usual dark purple-brown
colour; the marginal tentacles were of a light chocolate colour towards their tips, becoming paler
proximally. The labial tentacles and the disk and stomatodaeum were coloured similarly to the
marginal tentacles, the siphonoglyph, however, being colourless.

Structure. The stomatodaeum is short throughout the greater portion of its extent,

measuring only 7 mm. in breadth at a point about 1 cm. distant from the siphonoglyph. The
latter structure, however is prolonged downwards for a distance of 2 cm. and is very well markecl.

The column wall is thick and the mesogloeal processes which support the ectodermal
muscle fibres are well developed and closely set. The ectodermal musculature of the disk and
marginal tentacles is also well developed that of the labial tentacles, however, being feeble,
consisting of little more than a single crenated layer of muscle fibres, the mesogloeal processes
being hardly developed.

The state of preservation was too poor to allow of any study of the histological
peculiarities of the various parts, nor was it possible to determine by dissection the arrangement
of the mesenteries, the disintegrated endoderm matting them together so that they could not be
separated. This much, however could be determined, that a considerable number of mesenteries
extended to within 2 cm. of the aboral pole of the body, and that a single couple, which I
take to be the second couple of protocnemes, extended still further down, reaching the aboral
pole. By taking transverse sections at different levels of a strip of the column whose breadth,
starting at the mid-ventral line, amounted to about one-eighth of the entire circumference, it
was possible to determine the general arrangement of the mesenteries with approximate accuracy.
All the mesenteries in this strip, the directive included, this being readily recognizable by the
greater thickness of its mesogloea, extended to a distance of almost 3 cm. below the lower
border of the stomatodaeum; below this level the directive and each alternate mesentery lateral
to it had disappeared, the remaining mesenteries, as stated above, continuing downward to

27

28

tut : cm. trom th< tl pole. There is evidently then, a clear distinction of the two sets

of mesenteries, the brachycnemes and the macrocnemes, but whether the quartette arrangement
is manifested bj the alternate mesenteries of each sel being shorter, I could nol determine,

although it' present th<- difference in length must be comparatively slight.
lt is noticeable, too, that a marked diminution in the length of the
mesenteries as the mid-dorsal line is approached, is but slightly pronounced,
the great majority of the macrocnemes extending to the distance hom
the aboral pole mentioned above. In order to make clear th<- arrangement
which may bc supposed to exist from the observations recorded above,
a diagram of what I take to be the condition is appended (Text figureV .
but it must be remembered thal this represents onlj the arrangement on
the strii> studied by means of sections and that the relativa lengths of the
mesenteries of the two groups are conjectural. It may be added that in
the strip examined sixteen mesenteries wen- counted, which would give
12S as the total number, and this agrees well with the estimated number
of tentacles

In one important particular the mesenteries differ trom those of
other forms that have been examined, and that is in all the mesenteries
with the exception of the directives being fertile. The species is hermaphroditic
both ova and spermatozoa occurring in the s;ime mesentery, and they are
found as well on the brachycnemes as on the macrocnemes. This is a
marked departure trom what is found in other Cerianthans. but il does
not seem to be a peculiarity which demands the recognition of a new
nus, especially as but a single example of the species, and that not in
the best state of preservation was available for study.

Fig. V. ..... .

lüagmni showing thu ' idciltitv this torill with KWTJETNIEWSKl's LcriCllltllUS O »l/>OllCHSlS

the mesenteries wjth some hesitation, since in the description given by that author only

external characteristics are for the most part referred to. The general

dimensions of the two forms are, however, very similar, in both a Iarge number of mesenteries

extend to the vicinity of the aboral pole, and both rome from the same locality. These particulars

m to warrant the assumption of their identity.

2. Cerianthus sulcatus Kwietniewski.

Synonym: Cerianthus sulcatus n. sp. Kwietniewski. 1S98.
Stat. 1S1. Amboina anchorage, reef. 1 ex.

'ïeneral Form. The single example il'l. I. lig. 2), preserved in alcohol, had

nuch the same form as C. amóonensis, that is to say, it was rather short in proportion to its

h, with a constriction about '/■ cm- below the margin, enlarging below this to almost the

diameter of the margin and then tapering graduall) to the rounded aboral extremity. The

28

29

longitudinal striation of the column wall, mentioned by Kwietniewski, was but slightly prono-
unced and if I am right in my identification, cannot be considered characteristic of the species.
The marginal tentacles were long and slender, and numbered 81. They were apparently
arranged in four cycles, their formula being

i, 4,

■i o

ii 3i 2>4

i.

I. 2, I

4,

'1 Oi

!, 4, I -.

The labial tentacles were about one-third the length of the marginals and were of the same
number, the median tentacle being present, although considerably shorter than the others. The
formula for their arrangement in cycles was apparently

— 2, i, 3, 4 | 2, 3, i, 4 || 3, i, 4, 2, 4, i, 3 || 4, 1, 3, 2 | 4, 3, 1, 2 •-.

Dimensions. — The length of the column was 4 cm.; its diameter at the margin
2.5 cm., and at the middle of the column 2.0 cm. The length of the marginal tentacles was
3.0 — 3,5 cm., and their diameter at the base was 1 mm.; the length of the labial tentacles
was 1.0 — 1.2 cm., and their diameter at the base about 1 mm. The length of the stomatodaeum
was 1.2 cm.

C o 1 o u r. — The column was of a rather pale purple-brown, becoming lighter towards
the margin. Both sets of tentacles were almost colourless, a slight tinge of purplish-brown
being visible in some of them and appearing to indicate that their colourless condition was
the result of preservation. The stomatodaeum was pale, almost salmon-colour,
and the siphonoglyph colourless.

Structure. — The muscle processes supporting the ectodermal mus-
culature of the column wall were well developed and showed a tendency to
arise in groups from conical elevations of the mesogloea, a tendency which
was less pronounced near the margin than lower down.

As in the case of C. amboncnsis the parts were too much macerated
to allow of histological study, but by combining the study of sections with
dissections, it was possible to make out the arrangement of the mesenteries,
so far as their relative lengths were concerned (Text4igure VI). The directive
mesenteries extended to a distance of 9 mm. below the lower border of the
stomatodaeum and were succeeded on either side by a telocneme which
extended to the aboral pole. The third couple of protocnemes extended to
about 1.2 cm. below the stomatodaeum and the fourth couple to about
1.7 cm. The cleuterocnemes of the first quartette showed the typical alternating
arrangement so far as the brachycnemes were concerned, but no decided
alternation of length was discernible in the macrocnemes, these being for the
most part of about the same length as the fourth couple of protocnemes,
diminishing slightly, however, toward the dorsal mid4ine.

The presence or absence of craspedonemes on the upper portions of
the mesenteries could not be determined, but they occurred throughout the
length of the telocnemes in considerable numbers and were slender in form. No reproductive
cells were observed in anv of the mesenteries.

Fig. VI.

Diagram showing the
arrangement of the

mesenteries" of
Cerianthus sulcatus.

29

It is again with considerable hesitation that this form is identified with Kwietniewski's
its dimensions and the fact that it was taken in the same locality being the date
upon which the identification is based. The possibility <>l its being a young individual «'t i
is not excluded, although it seems improbable

rianthus n. sp.

St.it. 85. Lat. >., long. 119 2 ('.5 I , Makassar Strait. 724 metres. 1 ex.

General Form. The column is cylindrical (PI. I, fig. 3), enlarging slightly near

the margin but not tapering t<> any marked degree toward the rounded aboral pole. The
marginal tentacles are relatively short and slender, and appear to be arranged in only two

their formula being

2, \ , 2. \ ! 2,1.2.1 2,1.2, 1.2.1,2 1,2.1.2 | 1,2.1,2 — .

The oral tentacles are al most the same length as the marginals, except the median one, which
i> very much smaller than the rest. They are arranged in four cycles, their formula being

'. 2, 4, 3 1.2. 4, 3 | 1, 3, 4, 2, 4, 3. 1 3, 4, 2, 1 | 3, 4, 2, 1 — .

In addition to the seven protocnemic oral tentacles there were also five quartettes on eitber
side of the middle line, as well as some additional tentacles, possibly an additional (iitartette,
so that the total number of oral tentacles was not far from 55 and the number of the marginals
the same.

Dimensions. — Length of the column 6.0 cm.; diameter at about the middle of its
length 0.6 cm.: diameter at the margin 0.9 cm. Length of the marginal tentacles 0.7 cm.;
length of the oral tentacles about the same.

1 olour. The column, in the single example preserved in formalin, was colourless

throughout the greater part of its extent, becoming, however, purple-brown toward the margin.
Both the oral and marginal tentacles were colourless while the disc and stomatodseum were
of a pale chocdlate-brown colour.

Structure. I am not able to give a full account of the structure of this form.

1 he musculature of the column wall is well developed and the stomatod. rum was about o.S cm.
in length, the measurement being taken a little to one side of the siphonoglyph, which is.
however, but slightly i ed. The most striking feature observed on laying open the column

longitudinally was the smoothness of the lower 2.5 cm. of the column wall, none of the mesent-
eries, not even a pair of telocnemes, extending to the aboral pole or even to its vicinity.

il important points regarding the arrangement of the mesenteries must be left

rtain, owing to an unfortunate error having occurred in making preparations of the single

t the sp thi collection. It is certain, however, that the mesenteries were

ly sterile and fertile, that is to say, that brachyenemes and macrocnemes alternate, and

furthi there were strong indications that the deuterocnemes showed the quartette arrange-

\ but what the sequence in each quartette was I could not determine. It may be said,

30

3i

however, that the relative widths of the brachycnemes and the level at which they lost their
ciliated lobes of their filaments seemed to show that the longer one was the second in each
quartette; the relative lengths of the macrocnemes could not be determined. If this be the actual
sequence of the brachycnemes it constitutes a third type of arrangement of the deuterocnemes,
differino- from the two mentioned above (p. 15), but I do not feel sufficiënt confidence in the
reliability of my data to describe it definitely as a type.

So far as could be ascertained the mesenterial filaments had the usual cerianthan
arrangement and structure, but my preparations did not show any craspedonemes, although I
cannot state positively that they were absent. The fertile mesenteries contained both ova and
spermatozoa, the species being therefore hermaphrodite.

Larval Forms.
Genus Apiactis van Ben.
Synonym: Apiactis van Beneden, 1898.

Cerianthidae whose larval forms are more or less conical is shape, with no constriction
of the column wall immediately below the bases of the tentacles. Marginal tentacles short,
digitiforni; the median tentacle developes early, and the remaining ones quickly succeed the
corresponding mesenteries. The oral tentacles are small, tuberculiform. Siphonoglyph and directive
mesenteries short. Acontia in some cases slow in development.

I have modified van Beneden's definition of the genus so that it will include the form
to be described below, which seems most naturally referable to Apiactis, although it differs
from the type species in numerous details.

4. Apiactis oèconica n. sp.

Stat. [36. Ternate anchorage. Plankton. 1 ex.

Stat. 165. Anchorage on North-east side of Daram Island, (False Pisangs), east coast of Misool.

Plankton. 1 ex.
Stat. 172. Anchorage between Gisser Island and Ceram-Laut. Plankton. 3 ex.
Stat. [84. Anchorage oft" Kampong Kelang, south coast of Manipa Island. Plankton. 1 ex.

General form. — The column is conical in form, the aboral pole being truncated as
shown in PI. I, fig. 4 and 5, two of the examples from Stat. 172, however, being rounded at
the aboral pole and much less tapering. The summit of the column is surrounded by a circle
of marginal tentacles varying in number from 16 to 19, short and digitiform in shape and the
one corresponding to the directive mesenteries somewhat smaller than the rest (fig. 4). The oral
tentacles are small and tuberculiform and, indeed, could not be distinguished clearly in all the
specimens, nor could they be readily identified in sections. In one example, in which they were
especially distinct, they were nine in number, four on one side of the median line and five on
the other, the most medial on each side corresponding to the second intermesenterial chamber
on each side of the directive chamber, the three median chambers being without corresponding
oral tentacles.

31

Dimensión Nu.- length "t" the column was 2.0 2.5 min. and its diameter al the

margin was about the same.

olour. rhe column and oral disc had a faint brownish tinge and the tentacles

were a deeper shade "t" the same colour.

Structure. - rhe genera! arrangement <>t" the mesenteries is shown in the text-figure
VII, which represents a plan of one <<( the specimens reconstructed from serial sections '). rhe
have, however, been added from another individual, since in the one selected
mstruction they could not be clearly identified.

The siphonoglyph is but feebly marked and is not prolonged aborally, although the

directive mesenteries extend some distance below its lower border
The second protocnemes, counting laterally from the directives,
are provided with mesenterial filaments throughout nearly their
entire length, the filament being of the trefoil form down to a
short distance above its termination. These mesenteries are also
the longest and just above their termination each bears an acontium.
This combination of characters distinguishes them from all the
other mesenteries and clearly marks them as the telocnemes.

The two remaining protocnemes are similar to ene another
in structure, the third being somewhat shorter than the fourth.
Each possesses a relatively Ion- trefoil filament, that of the fourth
being the longer, and this is succeeded by a well marked branching
region. below which the filament disappears. Neither ol these
mesenteries bears acontia.

I M deuterocnemes there are present on one side five and

on the other si.\, the most dorsal mesentery on each side being

quite small and hardly projecting beyond the lower border of the stomatodaeum. Among the

two varieties may be recognized, in one of which the trefoil portion ot the mesentery is

much shorter than in the other, so that the branching portion begins at a much higher level

and there is a longer stretch of it devoid of a filament. It seems proper to regard the

of this variety as identical with the brachyenemes of the adult forms and those

of the other variety as corresponding to macrocnemes, and since the two varieties alternate,

is an indication of the quartette arrangement, the formula for the completed quartettes

being B M /> »i.

No reproductive organs occurred on any of the mesenteries. The state oi preservation
of tl Lamined did not permit of any study "f the minuter histological details, but it

may be stated that the mesogloea is throughout rather thin and exceedingly so in the mesenteries,
a condition very different from that described by van Beneden for Apiactis denticulata.

vu.

run showing the arrangement
of the nu mt tentacle

1:1, of larval form irtions are arbitntry, while

drawn to scale, the object beiog i<> reprcsenl thi lengths "I the parts. 11"

heavy lin earing the n esents the

! tlie filan

32

00

Genus Peponactis van Ben.

Synonomy: Peponactis van Beneden, 1898.

Cerianthidae whose larva? are almost spherical in shape, 'with short filiform marginal
tentacles, which are, in some species, rather late in developing. The median marginal tentacle
is similar to the others. The oral tentacles are small, enlarged at their extremity, and notably
inferior in number to the marginals. The siphonoglyph is moderately long; the directive
mesenteries are prolonged down the column for a considerable distance.

5. Peponactis pilula n. sp.

Stat. 37. Sailus Ketjil, Paternoster Islands. Plankton. 1 ex.

Stat. 96. South-east side of Pearl Bank, Sulu Archipelago. Plankton. Numerous ex.

Stat. 148. Lat. o°i7'.6S., long. i29°io'.5E. Halmahera Sea. Plankton. 1 ex.

Stat. 186. Lat. 30 lo'.5 S., long. i27°2o'.5 E. North side of Manipa Strait. Plankton. 1 ex.

The various examples from these different stations seem to belong to the same species,
which presents many differences from P. cequatorialis described by van Beneden (1898).

In form all the specimens were practically spherical (PI. I, fig. 6) a slight flattening of
the oral pole being the only divergence from what would otherwise be a perfect sphere. A
slight elongated depression marks the centre of this flattened area. The examples from Station
96 were all transparent, allowing the attachments of the mesenteries to be perceived with
ereat clearness throuo-h the column wall, but this was clue to the ectoderm having been mac-
erated away over the greater portion of the column, portions of it persisting only in the neigh-
bourhood of the depression at the oral pole. In the examples from Station $7 more of the
ectoderm had been retained, and in those from Stations 148 and 186 it was entirely preserved,
the specimens being in consequence quite opaque and therefore in marked contrast to those
from Station 96.

In P. czquatorialis van Beneden noted . the occurrence of both oral and marginal
tentacles, both sets being minute and filiform. In P. pilula no traces of tentacles could be
observed either in surface views or in sections. The difference may be due to difference in
age, since although the individuals of the two species that were studied were of practically the
same size, nevertheless the individuals of P. czquatorialis were in a somewhat more advanced
stage so far as the development of the mesenteries was concerned.

Dimensions. The majority of the examples measured from 3.0 to 3.5 mm. in

diameter, that from Station 148, however, being somewhat smaller, its diameter measuring
only - mm.

Coloüration. Most of the specimens were colourless throughout or else showed

a yellowish tinge toward the oral pole. The example from Station 37 was, however, yellowish
throughout, but whether this was normal or due to discolouration after preservation cannot
be determined.

Structure. — The series of sections prepared from the 2.0 mm. example was,

33

S1ROGA-EXPEDITIE XV Cl. 5

TIM

t ')

unfortunately, unsuccessful .nul th< account which follows is based entirely upon series prepared

individuals measuring about 3.0 mm. I h<- general arrangement of the mesenteries is shown

in t: mpanying textfigure \'I11, from which it will I"- seen that in addition to the eight

protocnemes, tuur deuterocnemes were present on either side, a some-

wh.it smaller rjumber than that OCCurring in individuals of .tliiiiit the
same size "t P. (equator ialis. The firsl couple "f protocnemes were.
as usual, short and entirely destitute of mesenterial filaments. The
cond couple were, on the other hand, the longest of all the m<
•.eiie-,. tor ;i consideratie distance below their separation from the
stomatodaeum they possessed no filaments, hut toward the aboral
extremity <>f each a filament appeared and it terminated after a short
course in a well developed acontium. The third couple po
filaments throughout almost their entire length, these filaments branching

of the mcsenleric> of a iini of

in part of their course. The fourth couple resembled the second so

vin.

g the a
tentene

far as the arrangement of the filaments was concerned, except that
filaments were even shorter and the acontia smaller.

The t'irst and third deuterocnemes on either side resembled the third protocnemes in

structure, and the second deuterocnemes resembled the fourth protocneme, except that they

-s no acontia: the fourth couple of deuterocnemes were as vet unprovided with filaments.

From the second protocnemes onward the lengths of the mesenteries diminished ^radually,

quartette arrangement of the deuterocnemes bein^ indicated only by the structure of their

filaments. It seems probable, however, that an alternatin^ difference of the quartette mesenteries

will appear with further development, since it is already clearly indicated in the figure of /'.

aquatorialis yiven by van Beneden. It is to be noted that in that form as well as in pilula,

-econd protocnemes are the longest of all the mesenteries and this fact, together with the

occurrence of acontia upon them in pilula, renders it ])robable that they will become the

telocnemes. The presence of acontia in pilula is in marked contrast to their absence in the

somewhat more advanced individuals of aquatorialis.

.\s regards the finer structure it may be stated that the mesogloea is thin throughout,

ially so in the mesenteries where it forms a sheet of extreme tenuity. The ectoderm

lins numerous gland cells and at the aboral pole nematocysts were quite abundant, although

wen- r r other portions of the column. The ectodermal musculature was well devel-

much ni' than in van Beneden's examples of aquatorialis, the muscle cells being

arranged "ii quite well developed muscle processes. The stomatodaeum presented the same

■al histological characters as in other forms and possesses a well marked siphonoglyph.

No reproductn were present in any of the mesenteries.

34

Family Arachnactid.e.

Acontiferae in which the fourth couple of protocnemes, counting from the mid-ventral
line, form the telocnemes. The second and third couples of protocnemes are sterile. Acontia
are borne in larval stages by the fourth protocnemes but never by the second.

Genus Pachycerianthus Roule.
Synonym : Pachycerianthus Roule, 1904.

Arachnactidse living imbedded in mud or sand and provided with a sheath composed of
felted nematocysts and foreign substances. Mesenteries and tentacles usually numerous and the
quartette arrangement of the deuterocnemes distinct. Type P . benedeni Roule, 1 904.

In 1 904 Roule established the genus Pachycerianthus for the reception of a form which
had been obtained in the Sea of Japan and which presented the peculiar arrangement of the
mesenteries (i. e. the telocnemes were the fourth protocnemes instead of the second) which I have
taken as one of the chief characteristics of the family Arachnactidae. Roule does not, however,
seem to have fully appreciated the taxonomie importance of his discovery, and the name which
he chose for the genus refers merely to a remarkable thickness of the directive mesenteries.

6. Pachyceriantlius fimbriatus nor. nom. J).

Synonomy: Cerianthus elongatus Kwietniewski, 1898.

Stat. 60. Haingsisi, Samau Island, near Timor. Reef. 1 ex.

Stat. 172. Gisser Island. Reef. 2 ex.

Stat. 174. Waru Bay, North coast of Ceram. Reef. 2 ex.

Stat. 213. Saleyer anchorage. Reef. 2 ex.

Stat. 220. Pasir Pandjang, west coast of Binongka. Reef. 2 ex.

Stat. 234. Nalahia Bay, Nusa-Laut. Reef. 3 ex.

Stat. 296. Noimini, south coast of Timor. Litoral. 1 ex.

Stat. 301. Pepela Bay, east coast of Rotti Island. Reef. 1 ex.

Stat. 303. Haingsisi, Samau Island. Reef. 1 ex.

I have already, in the introductory pages, described many of the structural peculiarities
of this species, as well as of that which follows, and it will be unnecessary to do more than
briefly summarize these here for the better characterization of the species.

It may remarked, in the first place, that the majority of the specimens had been preserved
in alcohol, with the unfortunate result that the internal organs were greatly macerated, the
mesenteries being as a rule so matted together by their craspeda as to render a proper study
of their arrangement almost impossible. Two specimens, however, those from Station 172, had
been preserved in formalin, and these were found to be in a most excellent state of preservation
both for macroscopic and microscopic examination, so that what follows is largely based upon
what was found in these individuals, although various points were confirmed, when possible by
an examination of others.

1) For explanation of change of name see foot-note p. 12.

35

All the individuals were taken in shallow water near the shore or on reefs and many
wei mpanied by the tube which they inhabited and which had the usual appearance and

composition.

The column is elongated PI. I. fig. ;• and of the usual Cerianthan form, tapering
rally, where il is provided with a terminal pore, and flaring out somewhat al the margin,
upon which the marginal tentacles are situated. rhese are numerous and rather slender and
ed in four cycles at the margin of the funnel shaped disc. h was not always easy
to distinguish between the third and fourth cycles, but where this could be done the arrange-
ment was found to be

— | 1,3, 2,4 [,3,2,4 i. 3, 1- 2, |, 3. ' 4, -• 3i ' 4. -■ 3. i I — ■
The labial tentacles were somewhat shorter than the marginals and appear to have an arrange-
ment that may be represented thus

■vi-.ii->->->! > ï 2 2 2 I 2 L2 32A3I2

Kwietniewsk] describes the marginal tentacles as arranged in three cycles, but finds

• in the case of the labials.

Dimensions. — Different individuals varied considerably in their dimensions. In the
two examples trom Station [72 .(preserved in formalin) the column measured in the one case
io.; cm. and in the other case 8.5 cm. in length, the diameter at the margin being in each
e 2.2 cm. Other individuals (preserved in alcohol) ranged between 15.0 and 4.7 cm. in
length, proportionate differences also occurring in the diameters; the measurements of the in-
dividuals from Station 172, given above, probably represent a fair average.

The tentacles also present a good deal of variation in length. The marginals were in
most individuals about 2.0 or 2.5 cm. in length with a diameter at the base ot trom 1 .0 to
1.5 mm., although in some cases they reached a length of 4.0 cm.; the labials were some-
what shorter, measuring as a rule about 1.5 cm. in length.

Colouration. The column is of the usual purple-brown colour, varying from a

very pale to a very deep shade. I he marginal tentacles frequently show traces of a brownish
louration, deeper toward the tips, while the labials are of a light greenish-yellow colour.
Structure. — In its histological features the column wall presents no special peculiarhi
The muscle lamellae for the ectodermal muscles, are from 0.4 to 0.6 mm. in height, and are
m^re widely separated than usual. about eighl occurring in each o.i mm. of a section taken
ai the leve) of the lower border of the stomatodaeum. A section of C. sulcatus taken at the
same level showed about 14 lamellae in the same distance and one of C. americanus about 17.
These differences may, however, be due in part or in whole to differences in contraction. The
muscle lamellae of the tentacles are noticeably better developed than usual. those ot the marginal
being about 0.02 mm. in height, while those of the labials are somewhat lower in
ith the lesser size of the tenta. Ii

ing the column by a longitudinal incision the stomatod. ium is seen to hav<
about 1 cm. and to be provided with a well marked siphonoglyph. Throughout the
of its the ectoderm is thrown into well marked folds, each ot which is

37

*•*.

o

supported upon a mesogloeal lamella. In this folded region the ectoderm is rich in gland cells,

its cilia are comparatively short and its basal

portion is occupied by muscle fibres arranged

in a single layer. As the siphonoglyph is

approached the folds suddenly cease at about

the line of attachment of the first couple of

deuterocnemes, and here also the mesogloea

thickens markedly. The general character of

the ectoderm remains unchanged, however, up

to the line of attachment of the second couple

of protocnemes, but there the gland cells almost

entirely disappear, the muscle fibres also vanish

and the cilia become much longer, these

peculiarities distinguishing the siphonoglyph

from the general stomatodaeal surface.

The arrangement of the mesenteries
has been indicated in the introductory portion
of this paper and in the definition of the genus,
but for the sake of completeness it may be
stated again together with certain details
previously omitted. The first protocnemes are
short (Text-fig. IX) and bear no mesenterial
filaments. As in P. bcnedeni they are unusually
thick and narrow throughout the extent of their
attachment to the stomatoda^um. The second
and third protocnemes are alike. Each is but
a little longer than the first and like it is
sterile, although provided with a mesenterial
filament which presents the structure usual on
microcnemes. The fourth protocnemes are the
telocnemes; they are fertile and extend to the
region of the aboral pole.

The deuterocnemes are arranged in
quartettes, the formula for each of these being
B — m — ó — M. None of the deuterocnemes
extend much beyond midway between the lower
border of the stomatoda^um and the aboral
pole, the longer macrocnemes of the six ventral
quartettes ending at about this level, while
those of the remaining quartettes are gradually
shorter toward the dorsal surface. The shorter

37

^

Vh

38

macrocnemes i>t' the ventral quartettes extend only al. out one-third the distance between the
stomatodseum and the aboral pole and the microcnemes are, ol course, even shorter, the longer
ones being slightl) ter than the second and third protocnemes.

aspedonemes in the form ol relatively short digitiform processes, are scattered at
intervals alen- the entire length of the macrocnemes, and the bunches of them, which are so
evident in ( ranaeeus and C. americanus a short distance below the stomatodaeum, though

rather inconspicuous on account of the shortness of the craspedonemes composing
them. In structure, also, the craspedonemes differ from those of C. amerïcanus, the two limbs
of the filament being separated 1>\ a distinct band of ectoderm and mesogloea, instead of being
tically in contact compare figs. 1 ; and i.j, pi. I

All the fertile mesenteries (macrocnemes) contained only ova in the two individuals
examined histologically ; there was nut tin- slightes tracé of hermaphroditism. TIn- ova when
fully developed contain a considerable amount of volk and have a dark brown colour, thus
making the macrocnemes especially conspicuous.

Systematic. The identification of this form with Kwietniewski's C.elorigatm (1898)
upon somewhat uncertain grounds, owing to the insufficiency of the data eoncernine; that
species. The form considered here resembles it, however, in the dimensions of the body and
tentacles and in that only two mesenteries extend aborally beyond the middle of the column.
These similarities, taken with the fact that the two forms come from the same general locality,
form the basis of the identification.

It is not improbable that the C. nobilis of Haddon and Shackelton (1893) may also
be identical, luit in this case also the data furnished by the sponsors are too incomplete to
allov. of certainty. The name nobilis has priority over fimèriatus if the two forms be really
identical, luit it seems preferable, lor tin- present, to employ a distinguishing term, leaving open
the question of the identity with nobilis.

7. Pachycerianthus monostickus n. sp.

Stat. 1S1. Ambon anchorage, reef. 2 ex

The two individuals which I refer to this species were both rather short, stout forms
with relatively long slender tentacles (PI. I. fig. 8). The greatest diameter of the column was
somewhat below the middle. where it tapered slightly to the rounded aboral extremity and
panding again a little toward the margin, which was longitudinally ridged.

I he marginal tentacles were Ion- and slender and were 47 in number. they were
arranged in two cycles, which, for the most part, alternated with one another, although the
alternation was not quite regular. The labials were 48 in number and were in marked contrast
with the marginals, being, in the first place, very short and, in the second place, arranged in
ries, a condition which sug the specific name that has heen chosen. The

rnedian ventral tentacle w; ent.

Dimensions. — The column measured 4.5 cm. in length, its greatest diameter being

39

2. o cm. The marginal tentacles were from 2.5 to 3.0 cm. in length, their diameter at the
base being about 1 mm., while the labials had a length of only 2.0 mm.

Colouration. — The column was of a pale violet brown colour, as were also the
disc and the labial tentacles. The marginal tentacles were colourless.

Structure. — On laying open the column by a dorsal longitudinal incision, the oral
disc is seen to be deeply concave and longitudinally ridged. The stomatodaeum possesses a
well developed siphonoglyph, on either side of which it becomes markedly
longer and then diminishes rapidly as it is traced dorsally, the lower border
thus showing a rounded projection on either side of the siphonoglyph.

The protocnemes of the first couple are very short, hardly projecting
below the lower border of the siphonoglyph (Text-fig. X). The second and
third couples are sterile, the second being about two-thirds the length of the
column and the third distinctly shorter. The fourth couple constitute the
telocnemes; they are fertile and extend to the aboral pole. The deuterocnemes
have a well marked quartette arrangement, the formula for each quartette
being S, f, s, F. The larger macrocnemes of the two or three ventral quar-
tettes extend almost to the aboral pole, but those of the remaining quartettes
diminish rapidlv toward the dorsal surface. The shorter macrocnemes of each

r J Fig. X.

quartette are much shorter than the longer ones, those of the ventral quar- Diagram showing the

.. . , . , r , arrangement of the

tettes hardly extending to half way between the lower border ot the stoma- mesenteries of Packycer.
todaeum and the aboral pole; the longer microcnemes are slightly shorter ianthus morwstichus.
than the shorter macrocnemes and the shorter microcnemes extend but a short distance beyond
the lower border of the stomatodaeum. Craspedonemes occur on the macrocnemes below the
stomatodaeum, but were not found along the margin of the gonophoric portions of the
mesenteries as in P. fimbriatus.

Larval Forms.

Genus Arachnactis M. Sars.
Synonym : Arachnactis M. Sars, 1846.

Arachnactidae whose larval forms have a spherical body in the early stages, later be-
coming elongated. Marginal tentacles long and slender, in the earlier stages several times the
length of the column ; the median unpaired marginal tentacle appears only after the development
of these corresponding to the fourth intermesenterial chamber.

The genus Arachnactis was established in 1846 by M. Sars for the reception of
A. alöida, a free-swimminer form found in the autumn and winter at Floroe Island, off the
coast of Norway. Since its discovery this species has frequently been under observation, notably
by Boveri (1890) Vanhöffen (1895), Fowler (1897) and E. van Beneden (1898). The last
named author showed that acontia occurred upon the fourth couple of protocnemes, and his
fiorures of forms with nine and thirteen marginal tentacles show that the second and third
couples possess a wavy filament, their sterile or microcnemic character being thereby indicated,

39

4°

while the filaments of the fourth couple are al most straight, an indication that the) are destined
to be fertile or ma mie in character. Add to these indications the facts ili.it in the older

larvae studied by van Beneden the fourth couple of protocnemes «rere longer than any of the
other mesenteries and that in the oldest individual studied by Vanhöffen these same mesenteries
dl) the longest of all and contained immature ova, and their identification as
ms fairly certain.
In [862 A. Agassiz described another free-swimming Cerianthid larva, which he referred
to the genus Arachnactis as . /. brachiolata, an identification which has remained unchall» 1
ever since. In 1890 M Intosh described a single specimen taken in the Bay of St. Andrews
as an Arachnactis, and later van Beneden (1891) gave a thorough description of a number
of individuals in different stages of development, collected by Bourne off the south-wesl coast
«'t* Ireland and referred to - /. albida. Van Beneden recognized .is the results of his studies
that these forms were different from those studied by Boveri (1889), and in his later paper
identified them with that described by M> Intosh and named them A. lloydii, on the
supposition that they would prove to be the young of C. lloydii. Previously to this, however,
Fowler had recognized the fact that the forms studied by van Beneden and also indiv-

iduals from Plymouth which he had himself studied were different from . /. albida, and named
them A. bournei, which term has the priority, until it is made certain that the forms are
really the larva' of C'. lloydii.

Both . /. brachiolata and . I. bournei present certain marked differences from A. albida.

Thus, in early stages the body of albida is short and almost spherical, while in the other two

ies it is more elongated and somewhat conical; the tentacles of albida are long and

slender, their length being many times the breadth of the disc, while in the other two their

'i is about equal to the diameter of the disc; and in albida the median marginal tentacle

appears only when the fourth couple of tentacles are already rather long, while in the other

two species the median marginal tentacle developes equally with the tentacles of the third

couple. How far these differences may be correlated with differences in the arrangement of the

nnot yet be determined. In the case of . /. albida, as has already been noted,

individuals with gonads and acontia have been observed, and there seems a tolerable certainty

that t; nterial arrangement of these: individuals is of the same type as

that of Pachycerianthus ; but no sufficiënt data are at present available for the

'i J' termination of the mesenterial arrangement of either . /. bournei or ./.

XL brachiolata. Th( oldest examples of the latter form that I have heen able

lhc to obtain possessed only seven tentacles and the mesenterial arrangement

arrangement ol . .

[ ,eD. was that indicated in the adjoining text-figure (Text-fig. XI). The second
couple of protocnemes is much more developed than anv of the other mesent-
eries, but whether this is a temporary condition, or really indicates that they
to form the teloi nemes is uncertain.

ng aside the possibility thus indicated it seems that in the certain differen 1
ibove there is a valid basis for the separation of brachiolata and bournei from albida,
■ • A to be described below, resembles albida in the particulars in question.

4°

4i

There are thus tvvo forms, albida and sibogce, which may be definitely regarded as representatives
of the genus Arachnactis, and two others, brachiolata and bournei, which should be removed
from that genus. What the systematic position of the latter two may be it is a little difficult
to say. Van Beneden (1898) has assigned A. bournei to C. lloydii, principally on the basis
that the areas of distribution of the two forms is essentially the same, and if this identification
be correct, it may be expected that it will be found that the second couple of protocnemes of
bournei actually do become the telocnemes. Similarly Kingsley (1904), with an equal amount
of probability, has regarded brachiolata as the larval form of C. vcrrillii, and if both these
identifications prove correct the two larval forms must be associated with the Dianthca nobilis
of Busch (1851), which is generally accepted as the larval form of C. membranacea.

8. Arachnactis sibogcc n. sp.

Stat. 96. South-east side of Pearl Bank, Sulu Archipelago. Plankton. 1 ex.

Stat. 205. Lohio Bay, Buton Strait. 3 ex.

Stat. 282. Between Nusa-Besi and the north-east point of Timor Island. 1 ex.

In the majority of the specimens which may be referred to this species the body is short
and almost spherical, but in an individual from Station 205 (PI. I, fig. 10) it is more elongated
and conical, this individual, however, notwithstanding its greater size and difference of form
being in practically the same stage of development as the others. The marginal tentacles in
all were nine or ten in number, four on each side of the median plane being long and slender,
while a median one was much smaller; four or five labial tentacles were present (PI. I, figs. 9
and 10). The individual from Station 96 cliffered from the rest in being much smaller and the
marginal tentacles, while considerably longer than the breadth of the disc, lacked the almost
disproportionate length which they possess in the other examples.

Dimensions. - In the example from Station 96 the diameter of the column was
0.6 mm. and the length of the longer tentacles was 1.5 mm. In the other spherical examples
the diameter of the column was 0.75 mm. and the longer marginal tentacles reached a length
of 3.5 mm. The conical example from Station 205 had a length of about 1.5 mm., and the
diameter at the margin was 0.6 mm. ; owing to their contorted form the length of the marginal
tentacles could not be determined accurately, but they seemed to be relatively shorter than
those of the other examples from the same Station.

Colouration. — All the specimens were completely colourless, the only indication of
a possible presence of pigment being a distinct opacity at the tips of the marginal tentacles.

Structure. - The arrangement of the mesenteries is shown in the adjoining, text-figure
(Text-fig. XII) prepared from one of the spherical examples from Station 205. In this there
were four couples of well developed marginal tentacles, a small median tentacle and on the
right side an additional tentacle whose fellow had not yet made its appearance. The labial
tentacles were five in number, two couples corresponding to the second and third couples of
marginal tentacles, while the odd one was one of an additional couple, developed, like the odd
marginal, upon the right sicle.

The mesenteries were twelve in number, equally distributed on each side of the median

SIBOGA-EXPEDITIE XV cl. 6

I ■■

line, although those on the right side were slightly more developed than those on the left.

rhe directives hardly projected beyond the lower border of the stomatodaeum, and on either

side of tin ut were two mesenteries, apparentlj of the sterile type, which

tended to about li;ilt wa\ between the lowei border of the stomatodaeum

and the aboral pole. Next on either si. Ie came a long mesentery, extending

almost to the aboral pole and bearing each an acontium; these, the fourth

iuple of protocnemes 1 take to be the telocnemes. < >f the deuterocnen

only two were present on either side of the median line: one of these
xii. •

ig the was of about the same length as the second and third protocnemes and

like these apparenth of the sterile type, while the other hardly projected

tentacles in .i larva * * ' ' ' ' J

beyond the lower 1 «order ot the stomatodaeum and had not yet developed
a mesenterial filament.
The locality from which . /. sióoga was obtained seems to preclude any probability of
its identity with ./. alóida. But in addition its distinctness is shown by the earlier development
of the acontia, the youngesl example of A. alóida described by van Beneden not showing them,
although it is in a slightly more advanced stage of development than the examples of A. sióoga,
possessing thirteen mesenteries and six labial tentacles as against twelve mesenteries and five
labial tentacles. Another difference exists in the length of the stomatodaeum, which is considerably
longer in A. siöoga than in . I. alóida, the mesenteries of the former species thereby appearing
somewhat shorter.

Genus Dactylactis van Beneden.

Synonym: Dactylactis van Beneden, 1898.

Larval Arachnactidae in which the marginal tentacles in earlv stages are not very much
longer than the column and are continuous on their aboral surface with the column wall, nol
being separated from it by a groove. Their ectoderm shows more or less distinctly a differentiation
into four hands, that of the oral and aboral surfaces being richly provided with nematocysts,
while these structures are almost lacking on the lateral surfaces; the median tentacle of the
developes early. The oral tentacles develope earlv. Column ovoid, or, in earlv stages,
ii al. I he directive mesenteries are prolonged some distance below the lower border of the
stomatodaeum and acontia are borne by the mesenteries of the fourth and sixth couples.

9. Dactylactis malayensis n. sp.

Stat. 172. Gi ei [sland, anchorage between tliis island and Ceram-Laut. Plankton. Numerous
examp]
tat. 185. Manipa Strait. HEN tical net, [536 m. to surface. 1 ex.

' )f this form there were numer< imples, the majority of which, however, had been

■ d in alcohol and were considerably distorted and shrunken. A number, fortunately, were
llently preserved in }".<„ formalin and these alom- were used for study.
all the body was ovoid in form PI. I. fig. \\\ and surmounted by a corona ot

42

43

moderately long tentacles which curved gracefully so that each had somewhat the form of a
sickle, as in the D. armata figured by van Beneden (1898), although the additional length of
the tentacles in the present species made the curvature more distinct. In some of the smaller
individuals, indeed, the tentacles were spread out almost at right angles to the axis of the
column as is Solasteractis, but there was no distinct groove marking the.junction of their
aboral surfaces with the column wall.

Dimensions. — Two distinct stages were represented in the collection. The examples
of the younger stage had a column length of about 1.25 mm. and the length of the marginal
tentacles varied from 1.0 to 2.0 mm. In the older individuals the length of the column varied
from 1.5 to 2.0 mm. and the length of the marginal tentacles was about 2.0 mm., although
in one example, owing to a greater contraction, they did not exceed 1 mm.

Colouration. — No colour remained in any of the examples.

Structure. — In the younger individuals there were seventeen marginal tentacles,
that is to say, eight couples and a median tentacle. The latter (PI. I, fig. 11) was indisting-
uishable by its length from the adjacent tentacles, while both members of the eighth couple
and the left member of the seventh couple were decidedly smaller than the others. Of the
labial tentacles there were six couples, the first couple corresponding to the second couple of
marginal tentacles and the others successively to the third, fourth, fifth, sixth and seventh
couples. No labial tentacles corresponding to the median or first couple of the marginals were
present, and, employing van Beneden's symbols the formula for the tentacles would be

TK T1. TM. T1 + T8

t7— t2 ts— t7.

The stomatodseum was rather deep, deepest in the region of the siphonoglyph and
diminishins: pradually thence toward the dorsal mid-line. Twenty ^^

mesenteries were present (Text-fig. XIII), an equal number on
either side of the mid-plane, although those of the right half of
the body were somewhat longer than those of the left half. The
directive mesenteries extended some distance below the lower
border of the siphonoglyph and were succeeded by two couples
provided with mesenterial filaments throughout only a portion of
their length. The fourth couple, on the other hand, were provided
with filaments throughout almost the whole length of their free
border and the filaments terminated in acontia. At this stage, it
is to be noted, these acontiferous mesenteries are shorter than
those of the second couple. To these protocnemic mesenteries
succeed six couples of deuterocnemes, gradually diminishing in
length, so that on the left side the last three mesenteries, and
on the right side the last two do not extend beyond the lower

border of the stomatodseum. The other deuterocnemes, which do extend below the stomatodreum,
are provided with mesenterial filaments alternately straight and contorted, except on the left

43

Fig. XIII.

Diagram showing the arrangement of

the mesenteries and tentacles in a larva

of Dactylactis malayensis.

1 1

. ulicn- the mem th couple does not yet show the contorted form which

it wil] probably present later. The difference in the form of the filaments may be >, 1 1 j > ] >
t<> indicate an alternation ol sterile and fertile mesenteries.

In the lai there were twenty marginal tentacles, that is to say, a median

tentacle and on the right side ten and on the lefl nine additional om-s, the must dorsal tentacle

markedly smaller than the others. < >f labial tentacles there were seventeen,
nine to the right of the median line and eight to the left of it. As in the earlier stage there
no median labial tentacle, but the most ventral couple now corresponded to the first couple
n\ marginals, s<> that the tentacle formula was

i ' -T1. T.M. T' + T10
ts— t1. t1— t9.

1 impared with the younger examples the most striking difference is this appearance of
the hrst couple of labial tentacles. They are considerably smaller than the second couple and
it would seem that their development is practically identical with that of the eighth labial and
ninth marginal couples.

As regards the mesenteries, these have increased t<> twenty-three, twelve of which be-
long to the right side and eleven to the left. They present essentially the same structure and

arrangement as in the younger examples, except that the
fourth couple of protocnemes, the acontiferous couple, are now
decidedly longer than the second couple (Text-fig. XIV

The differentiation of the ectoderm of the tentacles

into four hands is fairly distinct, but it is not carried to the

extenl of giving the tentacles a quadrangular section, the

condition they present being somewhat like that described by

van Beneden for D. e/egans, although the histological details

are quite different. On the lateral surfaces the supporting cells

are closely packed, gland cells being rare and nematocysts,

though present, relatively few. As a result the nuclei are closely

packed and in sections stained with haematoxylin these regions

are of a deep blue colour, contrast arly with the oral

and aboral surfaces which are much paler in colour. This is

due to the fact that on the aboral surface the nematocysts are

verj abundant, and on both surfaces there are numerous large

unstained gland cells, so that the supporting cells are much

numerous and their nuclei somewhat sparsel) scattered.

It is highly probable that this form is different from any of those described by van

The individuals of /). armata and D. digitata which he described an- of about

;am< ven slightly younger than the younger examples of D. malayensis, and yel

■'.'. less disparity in the lengths of the protocnemes and deuterocnemes, and in both

•'.i couple of protocnemes surpasses in length the second couple. And, as a further

M

XIV.
howing the arrangement of the

and tentacles in nn older larva
nsis.

45

distinction from D. armata, it may be pointed out that D. malayensis shows no exceptional
development of nematocysts in the aboral endoderm of the column, nor do its marginal tentacles
present a quadrangular form in section. Van Beneden's examples of D. inermis were all in a
decidedly earlier stage of development than the younger examples of D. malayensis, and a
comparison of the arrangement of the tentacles and mesenteries in the two forms is impossible.
The section of a marginal tentacle which van Beneden figures does not show the dense
crowding of the nuclei on the lateral surfaces which is so marked in D. malayensis, the aboral
band is of an entirely different character and the abundance of coarsely granular gland cells
throughout both the lateral and aboral areas is quite unlike what occurs in the malayan form.
On account of these differences it seems advisable to regard the two forms as distinct. The
example of D. elcgans is even younger than those of D. inermis, but its distinctness from
malayensis ma)' be accepted on the basis upon which van Beneden separates it from the other
forms described by him, namely, on the occurrence of large nematocysts with a spiral thread.
These do not occur in D. malayensis.

Gravier's D. bencdeni (1904), notwithstanding that its tentacles and mesenteries were
but little in excess numerically of those of the older examples of D. malayensis, is evidently
considerably more advanced in development, and it is difficult to say to what extent the
differences seen in the structure of the mesenteries in the two forms may be due to this fact.
It is possible that later stages of D. malayensis may also show two couples of acontiferous
mesenteries and a further development of the deuterocnemes until they resemble those of D.
bencdeni in arrangement. Unfortunately Gravier makes no statement as to the presence or
absence of a differentiation of the tentacular ectoderm. It seems preferable, in the face of so
much uncertainty, to regard the malayan form as distinct for the present.

It is not improbable that D. viridis described by Verrill (1898) may be identical with
one of the forms described by van Beneden, D. digitata possibly, as Verrill himself suggests.
The description which has been given of it is, hower," too inadequate for the determination of
its specific status, no account being furnished of its structural peculiarities.

Finally, it does not appear probable that D. malayensis can be identified with any of
the forms recently described by Senna (1907). Of these D. mammillata, captured in the Pacific
to the north of the Galapagos Islands, differs in lacking the differentiation of the ectoderm of
the tentacles, while the other three forms, D. discors, D. tardiva and D. prcccox, all from the
Bay of Bengal, differ in the fact that notwithstanding that they possess sixteen marginal tentacles
they show no indication of the development of labials, a condition in marked contrast to what
occurs in D. malayensis.

In addition to the forms described above empty tubes of Cerianthids were taken at the
followinsjf stations :

ö

Stat. 213. Saleyer anchorage and surroundings.

Stat. 302. Lat. io°27'.qS., long. I23°28'.7E., near Rotti Island. 216 metres.

Stat. 313. Anchorage east of Dangar Besar, Saleh Bay.

Stat. ?

45

All these presented the usual structure which distinguishes tubes formed bj Cerianthids,
but it is impossible t" say by wh.it Species the) were formed. lt may, however, be worth
mentioning th.it the tube from Station ?, as well as those inhabited by individuals of P. fimóriatui
and taken ,a Stations 171 and : 1 ;. contained imbedded in their substance numerous examples
of i ■ impare 1 1 w\ 111 1885).

At Station 95, lat. 5 i;.5-\.; long 119 40' E., Sulu Sea, 52 metres, another empt)
tube was obtained, which may be that of .1 Cerianthid, although it is ver) different in structure
from those usually formed by these creatures. It is 1 ;, cm. in length, and lias a diameter in its
flattened condition i>t' ^.5 cm. The outer surface is transversel) wrinkled, while the inner one
is al most smooth; it lias a pale brown <>r hempen colour and is rough and somewhat brittle
to the touch. In structure it is composed of a loosely felted mass of fine fibres, among which
scattered numerous long monaxial sponge spicules and also some elongated brittle dark-
brown setae, whose origin I am not able to determine. The fine fibres which compose the main
tissue of the tube resemble nematocyst threads, of which the ordinary tubes are formed, excepl
that they are many times thicker than these. It' they are reallj nematocyst threads, it may be
expected that the species which inhabits such a tube possesses nematocysts of an exceptional size.

46

BIBLIOGRAPHY.

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Boston Soc. Nat. Hist. VII. 1863.

1842. AGASSIZ, L. Nomenclator zoologicus. 1842.

1883. ANDRES, A. Le Attinie. Fauna und Flora des Golfes von Neapel. IX. 1883.

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1S98. Die Anthozoa. Ergeb. Plankton-Exped. der Humboldt Stift. II, K. e. 1898.

1830. Blainville, H. M. Zoophytes. Dict. Sci. Nat. LX. 1830.

1889. BOVERI, Tm. Über Entwicklung und Verwandtschaftsbeziehungen der Aktinien. Zeit. für wiss.

Zool. XLIX. 1889.
185 1. BUSCH, W. Beobachtungen über Anatomie und Entwicklung einiger wirbellosen Seethiere. Berlin. 185 1.
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Anthozoen. Ofver. Kongl. Vetensk. Akad. Forhandl. Stockholm. 1893.
1900. Ost-Afrikanische Actinien gesammelt von Herrn Dr. F. STUHLMANN, 1888 und 1889. Mitth.

a. d. Naturhist. Mus. Hamburg. XVII. 1900.

1908. Anthozoa. BRONN's Klassen u. Ordn. des Tierreichs. II, 2. 1903 — 1908.

1891. CERFONTAINE, P. Sur 1'organisation et le développement de differentes formes d'Anthozoaires. Buil.

Acad. Roy. Belgique. Ser. 3. XXII. 1891.
1909. Contributions a 1'étude des Cérianthides. Nouvelles recherches sur le Cerianthus oligopodus

(Cerf). Arch. de Biol. XXIV. 1909.
1830. DELLA CHIAJE, S. Memorie sulla Storia e Notomia degli animali senza Vertebre del Regno di

Napoli. Napoli. 1822 — 1830.
1860. DANIELSSEN, D. C. Om Cerianthus borealis n. sp. Forh. vidensk. Selsk. Christiania. 1860.
1902. DUERDEN, J. E. West Indian Madreporarian Polyps. Mem. Nat. Acad. Sci. Washington. VIII. 1902.
1902'. The Morphology of the Madreporaria. II. Increase of Mesenteries in Madrepora beyond the

Protocnemic stage. Arm. and Mag. Nat. Hist. Ser. 7. X. 1902.

1905. The Morphology of the Madreporaria. VI. The Fossula in Rugose Corals. Biolog. Buil. IX. 1905.

1891. Faurüt, L. Sur le Cerianthus membranaceus (Gmelin). Mem. Soc. Zool. de France. IV. 1891.
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Gén. Ser. 3. III. 1895.
1889. FlSCHER, P. Sur la disposition des tentacules chez les Cérianthes. Buil. Soc. Zool. de France. XIV. 1889.

1843. FORBES, E. On the genus Edwardsia, with descriptions of new species. Arm. and Mag. Nat. Hist.

Ser. I. XII. 1843.
[897. FOWLER, G. H. The later development of Arachnactis albida (M. Sars), with notes on Arachnactis

bournei (sp. n.). Proc. Zool. Soc. London. 1897.
1788. GMELIN, J. F. LiNNÉ's Systema Natura?. Ed. XIII. Lipsise. 1788 — 1793.
1860. Gosse, P. H. Actinologia Britannica. London. 1860.

1902. Gravier, Ch. Sur un Cerianthaire pélagique adulte. Comptes Rendus Acad. Sci. Paris. CXXXV. 1902.
1904. Recherches sur un Cerianthaire pélagique adulte du Golfe de Californie (Dactylactis benedeni

n. sp.). Arm. Sci. Nat. Ser. 8. Zool. XX. 1904.

47

ien I chinodermen und Würmci des Adriatischen- und Mittcl

ON, Alice M. Description of some new sp I Actiniaria i

mi;. Proc. Roy. Dublin Soc. N. S. VIII. i
I. Mémoire sur Ie Cérianthc. Ann. Sci. Nat. Zool. Ser. 4. I. 1

A'. A. On .1 new instance ol Symbiosis. Proc. Linnean Soc. New South Wales. IX. 1SS5.
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k. k. Acad. Wien. Math.-Naturwiss. Classe. LXXIX. [879.
Hertwig, O. an< R. Dii Actinien. Jenaische Zeitschr. XIV. 1879.

Hertwig, R. Report on the Actinaria. Reports Sci. Res. Vo II. M. S. Challenger. Zool. VI. [882.

I. Beitrage zui Naturgeschichte der Actinien. [sis. XXIII. 1830.

I. S. Description of Cerianthus borealis Verrill. Tufts College Studies. N° 8. 1904.
Kwietniewski, C. R. Actiniaria von Ambon und Thursday Island. Jenaische Denkschr. V. 1
in. G. M. R. Anthozoen. Det vidensk. Udbytte af Kan. uil). Hauchs Togter. V. 1893.
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.
S90. Mc MüRRlCH, J. 1'. Contributions on the Morphology of the Actinozoa, I. The Structure of Cerianthus
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ntributions on the Morphology of the Actinozoa. III. The Phylogeny of the Actinozoa. Journ.
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- Report on the Actiniae collected by the United States Fish Commission Steamer Albatross
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L. Sur un Cerianthaire nouveau. Comptes Rendus Acad. Sci. Paris. CXXXVIII. 1904.
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': XXX. I9O5.

-. M. Uber Arachnactis albida, einen schwimmenden Polypen. Fauna littoralis Norvegiae. I. 1846.
retning om en i Sommeren 1S59 foretagen zoologisk Reise ved [Cysten af Romsdals Amt.
Nyt. Mag. for Naturv. XI. 1861.

. II. S. Nomenclator zoologicus. 1
907. - \. Larve pelagiche di Attiniari. Race. planktoniche fatté dalle R.nave Liguria. I. 3. Firenze. 1907.

ï.AN/AM. L. Diversi animali nuovi. Mem. Soc. Ital. di Verona. II. 1784.
I .II. P. and K F. L. Three Species of Cerianthus from Southern California.

University of California Publications. Zool VI. 1909.
VANHÖFFEN, I. Untersuchungen über .Anatomie und Entwicklungsgeschichte von Arachnactis albida
. Biblioth. Zool. XX. [895.
, .\. E. Results "f Recent Dredging Expeditions on the Coast of New England. Amer.
Journ. Sci. Ser. 3. V. 1

scriptions of New American Actinians, with critica) Notes on other Species. I. Amer. Journ.
VI. l!

nres Arachnactis et Cerianthus. Arch. de Biol. VIII. 1888.
II. V. ( >n the Development of Manicina areolata. Journ. ol Morph. II. 1888.

EXPLANATION OF PLATES

PLATE I.

1.

3-

4-

6.

7-

IO.

1 1.

12.

'3-

'4-

IS-

tnthus ambonetisis. Station i8i, Ambon I. Natura! size.
int kus su /tii /us. Station 1S1. Ambon I. Natura] size.
ui/luis teedus. Station 85. Natura] size.
<iica. Station 172. 5.
Apiactis obconica. Station 10.

nactis pilula. Station 96. 10.

yceriantkus fimbriatus. Station 1S1, Ambon I. Natural size.
Pachycerianthus monos tichus. Station [81, Ambon 1. Natural size.
Arachnactis sibogce. Station 205. ■ 10.
Arachnactis sibogce. Station 205bis. X 10.
lactis malayensis. Station 172. 5.
Trilobed portion of a mesenterial filament of C. fimbriatus. • DL. = distal lobe; gl. = gland

cell ; M. = median streak; ;/. = nematocyst; PL. = proximal lobe. x 200.
Section of craspedoneme of P. fimbriatus. en. = endoderm; DL. = distal lobe; PL =■ proximal

lob o.

Section of craspedoneme of C. americanus. 200.
Section of the simple portion of a mesenterial filament of 1'. fimbriatus. X 200.

Siboga-Expediiie XV. J. Playfair Mc Ml:rkich Actiniaria

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RESULTATS DES EXPLORATIONS
ZOOLOGIQUES, BOTANIQUES, OCÉANOGRAPHIQUES ET GÉOLOGIQUES

ENTREPRISE3 ADX
INDES NÉERLANDAISES ORIENTALE9 CU 1899 1900,

a

bord du 8IBOGA

SOUS LE COMMANDEMENT DE

G. F. TYDEMAN

PUBLIÉS PAR
MA.X WEBER,

Chef de 1'expédition.

*I. Introductiou et dcscription de 1'expe'ditiou, Max Weber.
* II. Le bateau et sou équipement scientifique, G. F. Tydemati.
*11I. Resultats hydrographiques, G-. F. Tydeman.
IV. Foramiuifera, F. W. Winter.
*IV4/i. Xeuophyophora, F. E. Sc huize.
V. ltadiolaria, M. Hartmaan.
*VI. Porifera, G. C. J. Vosmaer et I. Ijima ').
VIL Flydropolypi, A. Billard.
* VIII. Stylasterina, S. J. Hickson et MÜe II. M. England.
*IX. Siphonophora, M"ea Lens et van Riemsdijk.
*X. Hydrnmedusae, O. Maas.
*XI. Scyphoniedusae, O. Maas.
• XII. Ctenophora, MU° F. Moser.

* XIII. Gorgonidae, Alcyonidae, J. Versluys, S. J. Hickson et
XIV. Penuatulidae, S. .1. Hickson. [O. C. Nutting').

*XV. Actiniaria, P. Mc Murrich1).
*XVI. Madreporaria, A. Alcock et L. Döderlein ').
XVII. Antipatharia, A. .T. van Pesch.

XVIII. Turbellavia, L. von Gr af f et R. R. von Stummer.
XIX. Cestodes, J. W. Spengel.
•XX. Nematomorpha, H. F. Nierstrasz.
*XXI. Chaetognatha, G. H. Fowlcr.
XXII. Nemertini, A. A. W. Hubrecht.
XXIII. Myzostomidae, R. R. von Stummer.
XXIV'. Polychacta erranlia, R. Horst.

XXIV'2. Polychaeta sedentaria, M. Caullery et F. Mesnif.
•XXV. Gep'hyrea, C. Ph. Sluiter.
*XXVI. Kutci'opneusta, J. W. Spengel.
• XXVWis. Ptcrobranchis, S. F. Harmer.

XXVII. ISrachiopoda, J. F. van Beminden.
XXVIII. Polyzoa, S. F. Harmer.
*XXIX. Copepoda, A. Scott').
*XXX. Ostracoda, G. W. Muller.
*XXXI. Cirrhipedia, P. P. C. Hoek1).
XXXII. Isopoda, H. J. [lansen.
XXXIII. Amphipoda, Ch. Pe'rez.
*XXX1V. Caprellidae, P. Mayer.

XXXV. Stomatopoda, H. J. Hansen.
* XXXVI. Cumacea, W. T. Cal man.
«XXXVII. Schizopoda, II. J. Hansen.
XXXVIII. Sergestidae, H. J. Hansen.
XXXIX. Decapoda, J. G. de Man.
*XL. Pantopoda, J. C. C. Loman.
XLI. Halobatidae, J. Th. Oudemans.
*XLII. Crinoidea, L. Döderlein et C. Vaney ').
•XLIII. Echinoidea, J. C. H. de Mcijeic.
*XLIV. Holothurioidea, C. Ph. Sluiter.
*XLV. Ophiuroidea, R. Kohier.
XLVI. Astetoidea, L. Döderlein.
•XLVII. Soleuogastres, H. F. Nierstrasz.
*XLVHI. Chitonidae, H. F. Nierstrasz.
*XLIX'. Prosobrauchia, M. M. Sehepman1).
*XLIX-. Prosobrauchia parasitica, H. F. Nierstrasz et M. M.
*L. Opisthobranchia, R. Bevgh. [Sehepman.

•LI. Heteropoda, J. J. Tesch.
•Lil. Pteropoda, J. J. Tesch.

LUI. Lamellibranchiata. P. Pelseneer et Ph. Dautzenberg.
*LIV. Scaphopoda, M"« M. Boissevain.

LV. Cephalopoda, L. J o u b i n.
*LVI. Tunicata, C. Ph. Sluiter et J. E. W. Ihle.
LVII. Pisces, Max Weber.
LVIII. Cetacea, Max Weber.
LIX. Liste des algues, Muie A. Weber.
*LX. Halimeda, MUe E. S. Barton. (Mme E. S. Gepp).
*LXI. Corallinaceae, M"'e A. Weber et M. F os 1 ie.
LXII. Codiaceae, A. et Mme E. S. Gepp.
LXIII. Diuoflagellata. Coccosphaeridae, J. P. I, otsy.
LXIV. Diatomaceae, J. P. Lotsy.
LXV. Deposita marina, O. B. Boggild.
LX VI. Resultats géologiques, A. Wichmann.

Siboga-Expeditie

THE

ACTINIARIA OF THE SÏBOGA EXPEDITION

BY

J. PLAYFAIR Mc MURRICH

University of Toronto. Canada

PART I.

CERIANTHARIA

With 1 plate and 14 text figures

Monographie XV a of:

UITKOMSTEN OP ZOOLOGISCH,
BOTANISCH, OCEANOGRAPHISCH EN GEOLOGISCH GEBIED

verzameld in Nederlandsen Oost-In dië 1899 — 1900

aan boord H. M. Siboga onder commando van
Luitenant ter zee ie kl. G. F. TYDEMAN

UITGEGEVEN DOOR

Dr. MAX WEBER

Prof. in Amsterdam, Leider der Expeditie

(met medewerking van de Maatschappij ter bevordering van het Natuurkundig
Onderzoek der Nederlandsche Koloniën)

BOEKHANDEL EN DRUKKERIJ

«OOMMM

E. J. BRILL

LEIDEN

Publié Octobre 1910

* Les numéros avec un astérique ont déja paru; ceux marqués 1) seulement en partie

Voor de uitgave van de resultaten der Siboga-Expeditië hebben
bijdragen beschikbaar gesteld:

appij ter bevordering v.m liet Natuurkundig Onderzoek der Nederlandsche
Koloniën.

Het Ministerie van Koloniën.

1 1- t Ministerie van Binnenlandsche Zaken.

Het Koninklijk Zoologisch Genootschap > Natura Artis Magistra" te Amsterdam.

I ><• «Oostersche Handel en Reederij" te Amsterdam.

IV Heer B. H i'i Waai. Oud-Consul-Gcneraal der Nederlanden te Kaapstad.

M. B. te Amsterdam.

The Elizabeth Thompson Science Fund.

CONDITIONS GÉNÉRALES DE VENTE.

i'. L'ouvragc du „Siboga" se composera d'une serie de monographies.

2°. Ces monographies paraitront au fur et a mesure qu'elles seront prêtes.

3°. Le prix de chaque monographie sera différent, raais nous avons adopté comme base générale du prix <Ie
ventc: pour une feuille d'imprcssion sans fig. flor. 0.15; pour une feuille avec fig. flor. 0.20 a 0.25;
pour une planche noire flor. 0.25; pour une planche colorice flor. 0.40; pour une photogravure flor. 0.60.

40. 11 y aura deux modes de souscription :

a. La souscription a l'ouvragc complet.

b. La souscription a des monographies séparées en nombrc restreint.
Dans cc dernier cas, le prix des monographies sera majoré de 25 °/0.

50. L'ouvi 1 réuni en volumes avec titres et index. Les souscripteurs ii 1'ouvrage complet recevront

ces titres et index, au fur et it mesure que chaque volume sera complet.

A^CJCX pöi Li • Souscription Monographies

a 1'ouvrage complet séparées

[e Livr. (Monogr. XLIV) C. Ph. Sluiter. Die Holothurien der Siboga-Expedition. Mit 10 Tafeln. / 6. — / 7.50

2e Livr. (Monogr. LX) E. S. Barton. The genus Halimeda. With 4 plates „ 1.80 „ 2.40

3e Livr. (Monogr. I) Max "Weber. Introduction et description de 1'expédition. Avec Liste des

Stations et 2 cartes n 6.75 „ 9. —

4e Livr. (Monogr. II) G. F. Tydeman. Description of the ship and appliances used for seientific

exploration. With 3 plates and illustrations '....„ 2. — „ 2.50

5e Livr. (Monogr. XLVII) H.F. Nierstrasz. The Solenogastres of the Siboga-Exp. With 6 plates. „ 3.90 „ 4.90

6e Livr. (Monogr. XIII) J. Versluys. Die Gorgoniden der Siboga-Expedition.

I. Die Chrysogorgiidae. Mit 170 Figuren im Text M 3. — „ 3.75

7e Livr. (Monogr. XVI a) A. Alcock. Report on the Deep-Sea Madreporaria of the Siboga::

Expedition. With 5 plates „ 4-6o „ 5.75

8e Livr. (Monogr. XXV) C. Ph. Sluiter. Die Sipunculiden und Echiuriden der Siboga-Exp.

Mit 4 Tafeln und 3 Figuren im Text „ 3- — „ 3-75

9e Livr. (Monogr. Vla) G. C. J. Vosmaer and J. H. Vemhout. The Poriïera of the Siboga-
Expedition. I. The genus Placospongia. With 5 plates „ 2.40 „ 3. —

I0« Livr. (Monogr. XI) Otto Maas. Die Scyphomedusen der Siboga-Expedition. Mit r2 Tafeln. „ 7.50 „ 9.50

11e Livr. (Monogr. XII) Fanny Moser. Die Ctenophoren der Siboga-Expedition. Mit 4 Tafeln. B 2.80 „ 3.50

12e Livr. (Monogr. XXXIV) P. Mayer. Die Caprellidae der Siboga-Expedition. Mit 10 Tafeln. „ 7.80 „ 9.75
13e Livr. (Monogr. III) G. F. Tydeman. Hydrographic results of the Siboga-Expedition. With

24 charts and plans and 3 charts of depths „ 9- — » 11.25

14e Livr. (Monogr. XLIII) J. C. H. deMeijere. Die Echinoidea der Siboga-Exp. Mit 23 Tafeln. „ 15.— „ 18.75

15e Livr. (Monogr. XLVrf) René Koehler. Ophiures de 1'Expédition du Siboga.

ie Partie. Ophiures de Mer profonde. Avec 36 Planches „ 16.50 „ 20.50

16e Livr. (Monogr. LII) J. J. Tesch. The Thecosomata and Gymnosomata of the Siboga-
Expedition. With 6 plates „ 3-75 » 4-7°

17e Livr. (Monogr. LVItf) C. Ph. Sluiter. Die Tunicaten der Siboga-Expedition.

I. Abteilung. Die socialen und holosomen Ascidien. Mit 15 Tafeln . ... . . „ 6.75 „ 9. —

18e Livr. (Monogr. LXI) A. Weber— van Bbsse and M. Foslie. The Corallinaceae of the Siboga-
Expedition. With 16 plates and 34 textfigures „ 12.50 „ 15.50

19e Livr. (Monogr. VIII) Sydney J. Hickson and Helen M. England. The Stylasterina of

the Siboga Expedition. With 3 plates „ 1-5° » "-90

20e Livr. (Monogr. XLVIII) H. F. Nierstrasz. Die Chitonen der Siboga-Exp. Mit 8 Tafeln. „ 5.— „ 6.25

2 ie Livr. (Monogr. XLV ö) René Koehler. Ophiures de 1'Expédition du Siboga.

2e Partie. Ophiures littorales. Avec 18 Planches » 10.25 „ 12.75

22e Livr. (Monogr. XXVUis) Sidney F. Harmer. The Pterobranchia of the Siboga-Expedition,

with an account of other species. With 14 plates and 2 text-figures „ 6.75 „ 9. —

23e Livr. (Monogr. XXXVI) W. T. Calman. The Cumacea of the Siboga Expedition. With

2 plates and 4 text-figures B i.So „ 2.40

24e Livr. (Monogr. LVLz) C. Ph. Sluiter. Die Tunicaten der Siboga-Expedition.

Supplement zu der I. Abteilung. Die socialen und holosomen Ascidien. Mit 1 Tafel. „ — .75 , I. —

Prix :

» l'uli

Livi M ! Rud. Bcrgh. Di< Opisthobranchiata dei Sibo cd. Mit 20 Tafcln. / 11.25 / 14-10

I ivt. M \ Otto Maas. Die Craspedoten Medusen d< 1 Exp. Mit 14 Tafel n, . 12.50

i. XIII o J. Versluys. • Expeditiön.

1!. Die Prim im 1 • xl und einer Karte. . . , 12.50 , 16.75

XXI G. Herbert Fowler. rhc Chaetognatha of the Siboga Expeditiön.

With j ]>!.!• 1 4.20 , 5.25

J. J. Tesch. Die Heteropoden dei Siboga-1 icpedition. Mit 14 Tafcln. - ' . . 9- —

30» 1 G. W. Muller. Die Ostracoden der Siboga-Exped. Mit 9 Tafeln. , 3.50 ,

Franz Eilhard Schulze. Die Xenophy ophoren der Siboga-Exped.

Mi: , 2.40 „ 3.—

LIV) Maria Boissevain. The Scaphopoda of the Siboga Expeditiön.

With '• plates and 39 textfigures 4*8° > 6. —

J. Vv\ Spengel. Studiën über die Enteropneusten der Siboga-Exp,

Mil 17 l.it'i In und 20 riguren im Text 14.- . 17.50

H. F. Nierstrasz. Die Nematomorpha der Siboga-Exp, Mit 3 Tafcln. . 2.80 , 3.50

XIII Sydney J. Hickson und J. Versluys. Die AJcyoniden der Siboga-
1. Coralliidse, I!. Pscudocladochonus Hicksoni. Mit 3 Tafcln und t61 iguren im Text. , 2.20 „ 2.75

Livr. (Monogr. XXXI, r] P. P. C. Hoek. The Cirripedia of the Siboga Expeditiön.

\. Cirripedia pedunculata. With io plates , 5.40 , 6.75

Livr. Xl.llr/ L. Döderlein. Di gestielten Crinoiden der Siboga-Expedition, Mit

23 Tafcln und 12 Figuren im Text „ 8. — , 10. —

IX] Albertine D. Lens and Thea van Riemsdijk. The Siphonophores
the Siboga Expeditiön. With 24 plates and 53 teXtfigures. 13.50 . 16. 7*5

■ ' IX 1 M. M. Schepman. The Prosobranchia of the SibogarExpedition.
Part I. Rhipido and Docoglossa, with an Appendix l>y Trof. R. BERGH.

With <i plates and, 3 textfigures „ 4.80 . 6. —

XI J. C. C. Loman. Die Pantopoden der Siboga-Expedition. Mit 15
In und .| Figuren im Text . „ 6.25 , 7.80

(Monogr. IA'I.i J. E. W. Ihle. Die Appendicularien der Siboga-Expedition, Mit 4
In und 10 Figuren im Text „ 4.S0 , 6. —

XLIX' M. M. Schepman und H. F. Nierstrasz. Parasitische Proso-
bcanchiei dei Siboga-Expedition. Mit 2 Tafcln „ 1.20 „ 1.50

XI. IX'/': M. M. Schepman. The Prosobranchia of the Siboga Expeditiön.
Tart I'. Taenioglossa and Ptenoglossa. With 7 plates , 4.50 , 5.00

• ivr. (M XXIX o Andrew Scott. The Copepoda of the Siboga Expeditiön.

Part I. Free-swimming, LittoraJ and Semi-parasitic Copepoda. With 69 plates. . ,'26. — „32.50

LV1 C. Ph. Sluiter. Die Tunicaten der Siboga-Expedition.
IT. Abteilun Die Merosomen Ascidien. Mit 8 Tafeln und 2 Figuren im Text. . •,.'--, . 7.25

Livr. (Monogr. XLIX'f) M. M. Schepman. The Prosobranchia of the Siboga Expeditiön.

Part 111. Gymnoglossa. With 1 plate „ — .80 „ 1. —

Livr. Monogr. X 1 1 1 /> C. C. Nutting. The Gorgonacea of the Siboga Expeditiön.

III. The Muriceidae. With 22 plates , 8.50 , 10.75

48c I.ivr. (Monogr. XIII /■ ' C. C. Nutting. The Gorgonacea of the Siboga Expeditiön.

IV. The Plexauridze. With 4 plates , 1.60 „ 2. —

;r. LVIrf) J. E. W. Ihle. Die Thaliaceen (einschliesslich Pyrosomen) der
Expeditiön. Mit 1 Tafel und 6 Figuren im Text , 1.75 , 2.20

ivr. M C. C. Nutting. The Gorgonacea of the Siboga Expeditiön.

V. The Isldae. With 6 plates , 2.25 . 3.—

gr. XXXVII H. J. Hansen. The Schizopoda of the S;boga Expeditiön. With
d 3 text figures , 12.75 , 16. —

XIII/'3) C. C. Nutting. The Gorgonacea of the Siboga Expeditiön.

With 1 1 plates „ 4. — , 5. —

53' J. Playfair Mc Murrich. The Actiniaria of the Siboga Expeditiön.

With 1 plate and 14 text figures „ 2.20 „ 2.75

r. = Mrk 1.70 = I sh. 8 tl. = frs 2.12 en chiffres arromlics.