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THE THECOSOMATA AND GYMNOSOMATA

OE THE SIBOGA-EXPEDITION

Siboga-Expeditie

LII

//

THE THECOSOMATA AND GYMNOSOMATA
OF THE SIBOGA-EXPEDITION

HY

j. j TESCH

Utrecht

With six plates

-==l>è@5^l<

LATE E. J. BRILL

PCBLISHERS AND PRINTERS

I.EYDEN — 1904

THE THECOSOMATA AND GYMNOSOMATA
OF THE SIBOGA-EXPEDITION

BY

J. J. TESCH

Utrecht.

W i t h s i X p 1 a t e s.

INTRODUCTION.

The occurrence of Thecosomata and Gymnosomata, composing together the group ot
the so-called "Pteropoda", in the seas now explored by the Siboga, has been stated only a
few times.

Though OoY and Gaimard, on the voyage of the Astrolabe, already described several
species from Amboina, yet the indications and figures of these zoologists are too fragmentary
and incomplete, to throvv some more Hght on the knowledge of these animals.

Afterwards it has been, properly speaking, only the Challenger, which collected specimens
from a few places (North of New-Guinea and off the Philippines). Moreover I can mention a
Note of V. ScHÉELE (list of literature, Munthe 1886). I have also seen some specimens of
Thecosomata from the Sunda Straits and Java Sea (Utrecht Zoological Museum).

In a study on the geographical distribution of such essentially pelagic animals as the
"Pteropoda" are, I have preferred to take a larger field of exploration than the area in which
the Siboga-material was collected.

For that reason I have accepted the Australasian province, proposed by Pelseneeé ^)
(almost agreeing with the Indian province of Keferstein ^), viz. the East-Indian Archipelago,
the China Sea, the Philippines and the seas of North-Australia.

i) Challenger Report. LVIII, p. 62.
2) In Bronn's Thierreich. Bd. III, p.
SIBOGA-EXPEDITIE UI.

^476^

In this pelagic province 26 species of Thecosomata have been found until now, which
are all mentioned in this Report; 23 of these species are represented in the collection, brought
home by the Siboga ; 4 of them are new.

Of the 10 species of Gymnosomata, now recorded from the province in question, only
2 were not found again. Besides, 5 species out of the 8 had not been described yet. One
species belongs to a new genus. So, from a systematic point of view, we may say that these
results are satisfactory.

Notwithstanding the anatomy of the two groups has already been studied by rather a
great number of previous authors, yet I thought it not superfluous to make another inquiry into
the anatomy, to which I could perhaps contribute something and add a few corrections of former
statements. For anatomical purposes I made use of the material of the Siboga-Expedition, of
the Leyden Museum, of the Zoological Museum of Amsterdam and of the Utrecht Museum.

It has never been my intention to give an anatomical monograph, nor even a complete
comparative study, as has already been so excellently done by Pelseneer ^). For such a
purpose, the material at my disposal has been insufficiënt. After the discussion of every genus,
I have given some anatomical notes, in which I confined myself chiefly to those facts, which
were new or contrary to previous assertions.

Though I am aware of many lacunae in my study on the anatomy, they are very often
not my fault, but due to want of material. For the rest, I greatly hope to complete these
researches and to add histological and embryological facts at the Naples Zoological Station.

Lastly I have to thank my esteemed teacher, prof. Hubrecht, who, during my study
at the Utrecht Laboratory, assisted me with his great experience, also Dr. H. F. Nierstrasz,
who supplied me with material from Naples, and finally Dr. R. Horst, by whom the material
of the Leyden Museum was sent to me. Since my stay in London I keep in grateful
remembrance the names of Prof. F. J. Bell and mr. Edg. A. Smith, through whose kindness I
have had occasion to study the material of the Challenger, and the valuable collection of
thecosomatous shells in the British Museum.

1) Challenger Report. LXVL

CLASSIFICATION OF THE 'TTEROPODA'

In the phylum Mollusca there are still always some groups, the systematic place of
which has usually been misunderstood. Partly this must be attributed to the still very incomplete
knowledge we possess about their anatomy and embryology, so that many and serious
investigations are still necessary to throw some light on affinities, difficultly to be discovered —
partly, however, also to conservative ideas, a habit to keep old divisions and notions — I
should nearly saj- : though the zoologists themselves knew better.

But this being the case, the more it is every investigator's duty, who has had the
opportunity to study such a "doubtful" group, to point out wherever he can, the phylogenetic
affinity of the group to others. For this relation, though it has been proved long ago, has not yet
generally been accepted. So it will perhaps not be bad to give once more a short survey of the
different opinions, which have prevailed and prevail still with respect to the systematic position.

We need not stop long at the opinions of the first investigators, who wished to classify
the Pteropoda with other groups. So in 1756 Browne ^) classified some animals which he
described as Clio among the Zoophytes; while ForskAl ^) thought that .his "■ Anomia tridentata'
belonged to the group of the Acephala.

Lamarck ^) was of the same opinion afterwards ; he too brought Clio and Pneumo-
noderiiia to this class, and thought that they formeel a transition of the Acephala to the
Gastropoda. On the expedition of Lapeyrouse Lamartinière *) found an animal which he
recognised as having been described by Browne, and classified it among the Insects. In those
years the lower animals were all grouped with the Insecta or the Vermes. Pallas '), who
examined ^ Clione dorealis'\ found some resemblance with the genus Sepia of Linnë.

With Cuvier's examination of '^ Clio borealis\ the systematic place of this animal became
somewhat more distinct. Cuvier •*) denied the affinity with his Cephalopoda and found the

1) The civil and natural histoiy of Jamaica, p. 3S6.

2) Faune arabique. p. 124, 1773.

3) Philosophie Zoölogique. Vol. I, p. 319.

4) Journal de physique. Septembre 1787.

5) Spicilegia zoologica. Fase. X, p. 28, tab. I, fig. N" 19, 1774.

6) Mémoire sur Ie Clio borealis. Ann. Mus. d"Hist. Nat. Paris 1802, Vol. II, p. 249.

resemblance with Gastropoda greater and in consequence did not think it necessary to bring
Clio to a separate order. Yet, this was done by him two years afterwards ^). And on his great
authority only, later investigators accepted his division.

The "ordre des Ptéropodes" remained, and the only modification, made by Cuvier himself
afterwards'), was that the "orders" of Cuvier were now called "classes". That the notion of
"class, order" etc. was not yet fully comprehended, is illustrated by the following fact : in 1810
Péron and Lesueur, who have the same opinion as Cuvier with respect to the systematic
treatment, speak of the "familie des Ptéropodes" in their article : Histoire de la familie des
Mollusques Ptéropodes. Ann. Mus. d'Hist. Nat. Paris 18 10. Vol. XV, p. 71.

That the Pteropoda constitute a separate class among the Mollusca has long been a
prevalent opinion and is perhaps so still. It would be going too far, to mention the names of
all those who have stuck to this opinion.

Of the zoologists of later time, some of whom have at least made studies of their own
about the organisation of the Pteropoda, the best known are :

LOVÉN (1848), TrOSCHEL (1848), OWEN (1S55), BURMEISTER (1856), WoODWARD (1856),

Keferstein (1866), ScHMARDA (1872), voN Ihering (i8;6), Huxley (1877), Gegenbaur (1878),
Claus (1882).

In this respect we must not overlook the fact that Gegenbaur ^) brought Gastropoda,
Pteropoda and Heteropoda all to one class, viz. the Cephalophora ("Gastropoda im weiteren
Sinne"), maintained this opinion in his "Vergleichende Anatomie", and then changed his mind so
much afterwards. On the other hand. Claus regards the Pteropoda as an order of the Gastropoda
in his third edition of his "Lehrbuch der Zoölogie" p. 574 (1885). And voN Ihering, who in
1876^) emphatically pointed to the conformity of the two classes: Pteropoda and Cephalopoda
has changed his opinion afterwards ^), at least with respect to the pretended resemblance.

The general conviction is that the Pteropoda are nearest related to the Cephalopoda.
This opinion, maintained by many zoologists so persistently, was principally founded on the
resemblance of the head-appendages of the Gymnosomata and the arms of the Cephalopods.

Some have even gone so far that they regarded the Pteropoda as an order of the
Cephalopoda. This idea, first pronounced by Oken °), was held afterwards by Ray Lankester '),
who divided the class Cephalopoda in two groujas :

a. Pteropoda and h. Siphonopoda (= Cephalopoda s. str.).

It was in 1821 that de Blainville pointed out the many points of resemblance which
the Pteropoda had with the Gastropoda "). It was his opinion that the Bulloidea were the

1) Sur l'Hyale. Sur un nouveau genre de Mollusques nus (Ie Pneumodermon) et sur rétablissement d'un nouvel ordre de
Mollusques (les Ptéropodes). Ann. Mus. d'Hist. Nat. Paris, Vol. IV, p. 232.

2) Règne animal. Paris 181 7, Vol. II. p. 378.

3) Gegenbaur. Untersuchungen über Pteropoden und Heteropoden. Leipzig 1855, p. 189.

4) ^'^''gl- Anatomie des Nervensystems und Phylogenie der MoUusken. 1876, p. 272.

5) Zeitschr. Wissenschaftl. Zool. 1881, Bd. 35, p. 4. Über die Verwandschaftsbeziehungen der Cephalopoden.

6) Lehrbuch der Zoölogie. Bd. I, p. 326.

7) Encyclopaedia Britannica. g'h Ed. Vol. XVI, 1883.

8) Dict. des sciences naturelles. Prt. XXII, p. 66.

nearest relations of the Pteropoda. Some years afterwards, hc applicd ihis opinion to his classification
of the Molkisca ^). This view of the matter, combated by de Férussac -) and d'Orbigny '') vvith
many woi-ds and apodictic sentences, but not with arguments, found however defenders.

First it was Deshayes *), who for the rest did not give observations of his own nor
procured new proofs — but it was Souleyet especially, who with extraordinary abilit)' defended
his opinion '") and, after a long series of researches of his own, adhercd to de Blainville's opinion.

Clarke in England (1S51) had classified the Pteropoda among the Opisthobranchia,
but had not made researches himself, as far as I know at least, while Leuckart (1848) also
mentions the Pteropoda, as being an order among the Gastropoda.

But in the many years that foliowed this period, there was scarcely a zoologist who
pronounced an opinion about de Blainville's views. The "class" of the Pteropoda remained
and it was not until a thirty years after, in 1880, that Spengel ") reckoned the Pteropoda
among the Gastropoda Euthyneura and, a short time after, Grobben '^) expressed his opinion
that the Pteropoda were an order of the Gastropoda, while he considers Gasteropteron as very
nearly related to the Pteropoda at any rata.

Soon after, within a short time, two works appeared, which after that of Souleyet,
being founded on extensive researches of their authors, have attributed most of all to the opinion
that the Pteropoda belong to the Gastropoda.

Boas's study **), which appeared in 1886, chiefly treated of the systematic position. But
his numerous arguments and the causal connection, pointed out by him, between the gradually
changing organisation and the pelagic way of living of the Pteropoda, made the correctness of
de Blainville's opinion indisputable.

Just as DE Blainville had done already, Boas too regarded the Bulloidea as the
nearest relations of the Thecosomata '''). But he did not express an opinion on the question,
from which group of the Tectibranchia the Gymnosomata descended '"). Here the foUowing
question presents itself for the first time : whether the Thecosomata and Gymnosomata really
possess that near affinity which can justify their union to one group, the "Pteropoda".

Boas was the first who indicated the great difference between these two sub-groups.
And in saying that the fins were not homologous, he proposed that henceforth ^^) the Thecosomata
should be called Eupteropoda and the Gymnosomata Pterota.

i) Manuel de Malacologie et de Conchyliologie. 1825. The Pteropoda are regarded as an order, the Aporobranchia, and divided
into Thecosomata and Gymnosomata. The genus Liinaciiia^ called by him SpiyatcUa^ was classified by him as belonging to the Heteropoda.

2) Hist. nat. générale et particuliere des Mollusques. p. 37.

3) Voyage dans l'Amérique meridionale. Vol. V, p. 65.

4) Encyclopédie Méthodique. Hist. Nat. des Vers. Paris 1830, Vol. II, p. 552.

5) Voyage de la Bonite. Paris 1852, Vol. II, p. 88 — 8g.

6) Geruchsorgane und Nervensystem der MoUusken. Zeitschr. Wissenschaftliche Zoölogie. Bd. XL, p. 373. Also see p. 366
and p. 381, note I.

7) Morphologische Studiën über den Haru- und Geschlechtsapparat, sowie die Leibeshöhle der Cephalopoden. Arb. Zool. Inst.
Wien 1884, Bd. V, p. 61—67.

8^ Boas. Spolia .\tlantica. Bidrag til Pteropodernes Morfologi og Systematik samt til Kundskaben om deres geografiske
Udredelse. Vidensk. Selsk. Skr. 6. Raekke. Bd. IV, i.
g) Op. cit. p. 36.

10) Op. cit. p. 149.

11) Op. cit. p. 13 and 14.

Still more than Boas, it is Pelseneer who has largely contributed to the knowledge of these
Mollusca. In 1885 he expressed his opinion ^) that the Pteropoda were related to the Euthyneura
and this conviction was kept by him in the years following "). In the Challenger Reports
we find his most extensive paper, written on this subject ''). In this work, after treating in details
the confused nomenclature and establishing the precisely different types (something which can
only be mentioned here in a few lines), he discussed briefly and distinctly the different opinions
with respect to the systematic place of the Pteropoda.

It would be going too far to expatiate long, on what Pelseneer has explained in his
work with an abundance of proofs, taken from anatomy. Some of the results of his study,
though somewhat abridged, follow here "').

A. The Pteropoda do not constitute among the Mollusca a class of the same value as the

Cephalojjoda, Gastropoda, etc.

B. The Pteropoda are not primitive Mollusca, but are a derived and recent group.

C. Thev have no affinity with the Cephalopoda.

D. They are Gastropoda, in which the adaptation to pelagic life has so modified their external

character, as to give them an apparent symmetry.

E. Among the Gastropoda they do not constitute a distinct class, not even an order.

F. They belong to the Euthyneura and among these to the Tectibranchiate Opisthobranchs.

G. The Pteropoda are polyphyletic in their origin ; the Thecosomata and Gymnosomata are

two independent groups.
H. The Thecosomata have descended from the Bulloidea.
/. The Gjmnosomata have descended from the Aplysioidea.

From these results we learn that the group of the Pteropoda, according to Pelseneer,
is an unnatural union of Thecosomata and Gymnosomata, two sections which must be classified
separately to the Tectibranchia, and so the Thecosomata to the Bulloidea (Cephalaspidea) and
the Gymnosomata to the Aplysioidea (Anaspidea).

In this short survey on the subject, there can be no question of going into details with respect
to Pelseneer's arguments, and it is sufficiënt to draw the attention to the fact that the Pteropoda
are of polyphyletic origin. Pelseneer denies, that the fins of the Thecosomata and Gymnosomata
should not be homologous ; according to him the fins of both the groups are parapodia.

In the fifteen years that have passed since Pelseneer's work appeared. his opinion and
that of Boas on the Gastropoda-nature of the Pteropoda, has graduallv found more adherents.
Though few researches have been made since 1888 and only some articles on a single specimen
or a single organ have been written, yet different zoologists have become convinced of the
correctness of Pelseneer's assertion.

i) The cephalic appendages of the Gymnosomatous Pteropoda and especially of Clione. Quavterly journal Mier. Sc. (2)
Vol. 25, p. 506.

2) Recherches sur Ie système nerveux des Ptéropodes. .\rch. de Biol. T. VII, p. 127. Description d'un nouveau genre de
Ptéropode Gymnosome. Buil. se. Dép. du Nord. p. 226.

3) Zool. Chall. Rep. LVIII, Gymnosomata, 1S87. LXV, 1888 (Thecosomata). Prt. LXVI (Anatomy of Pteropoda).

4) Challenger Report. LXVI, p. 95, 96.

Amono- them I can mention Simroth '), Crosse -), Grobben ^), Korsci-ielt *), and von
Ihering '). In most manuals anti icxt-botjks on zoology, the Pteropoda are mentioned either as
an order of the Gastropoda, or as a snb-order of ^the Opisthobranchia "). Yet the pretended
relationship of the Pteropoda with the Cephalopoda has given occasion to Schalfejeff '') to
draw the attention to the homology of the head-appendages of Clione with the arms of the
Decapoda. Smitii "), though referring to Pelseneer, calls the Pteropoda a separate class (a
mistake also made by Vogt and Yung some years before ^) ; while the title of Vitj.ot's work ^")
with respect to the classification of the MoUusca, does not seem justified in any respect, and
his systematization is anything but "actuel".

That the Pteropoda descend from the Tectibranchia is no more a knotty point, but a
question on which most investigators have agreed.

(Jn the polyphyletic origin of the Thecosomata and Gymnosomata and for that reason
their not admitting of the name "Pteropoda", only few have expressed an opinion.

Though the foundation of Boas's opinion was said to be wrong, according to Pelseneer,
yet the latter has adduced sufficiënt proofs, which justify his opinion on the different origin of
both groups of Pteropoda. Later on, Simroth has acknowledged that the conformity between
Thecosomata and Gymnosomata was only apparent and is founded on convergency.

Mazzarelli ^^), who examined the Aplj-sioidea, says that they are connected bv the
Xotarchidae with the Pteropoda ''), which is also mentioned by Pelseneer, who spoke about a
Notarchus-form as being the precursor of the Gymnosomata, Korschelt ^^), however, thinks that
embr}-ology speaks in favour of a very near affinit)- between the two groups and that the
Gj-mnosomata are phylogenetically younger than the Thecosomata and descend from these, an
assertion, formerly pronounced by Wagner ^*). xAs to myself, I have been able to study rather
extensively the anatomy of the Thecosomata as well as of the Gymnosomata. And because
nearly always — and with respect to the main points continually — I found Pelseneer's
researches affirmed by mine, I cannot but agree with him. And, referring to the results
mentioned above, I can only conhrm his assertions. For that reason I think it better, not to
use the name Pteropoda any longer, as it combines two groups, which in fact have no more
connection with each other, as is expressed by the characters of Bulloidea and Aplysioidea.

i) Ueber einige Tagesfiagen der Malacozoologie, hauptsachlich Convergenz-Erscheiaungen betreffend. Zeitschr. Nalurw. Halle
18S9, Bd. 62, p. 65—97.

2) A new classification of the Mollusca by W. H. Dall. Journ. Conchyl. 1S84. Paris 1889, Tomé 29, p. 82, 83.

3) Zur Morphologie des Pteropodenkörpers. Arb. Zool. Inst. Wien 1S89, 8'-''' Bd., p. 155 — 157.

4) Lehrbuch d. Vergl. Entw. Gesch. der Wirbell. Thiere. Spec. Theil. Jena 1893. (MoUuscs by' Korschelt).

5) Sur les relations naturelles des Cochlides et des Ichnopodes. Buil. Sc. France. Tomé 23, p. 148 — 257.

6) R. Hertwig (1894), The C.ambridge Natural History (Molluscs by Cooke) 1895, Parker and Haswell (Textbook of
Zoology, 1897), Goette (1902). Also in the Zool. Record since 1892, and in Lang's Lehrbuch der Vergl. Anatomie der Wirbellosen Thiere.

7) Zur Anatomie der Clione Limacina Phipps. Zool. .Anz. 12 Jahrgang. p. 188 — 190.

8) Report on the Marine MoUuscan Fauna of the Islands of St. Helena. P. Z. S. 1890. Pteropoda. p. 254.

9) Lehrb. d. Pract. Vergl. Anatomie. Bd. I. Pteropoda. p. 828 — 852.

10) La classification zoölogique dans l'état actuel de la science. Revue Biol. Lille 1891, 3'^"": année, p. 245 — 261.

11) Monografia delle .\plysiidae del golfo di Napoli. Méra. Soc. Ital. Sc. dei XL (3). Tonio 9, N« 4, 1893.

12) To my opinion it would have been bettev to say: Gymnosomata.

13) Op. cit. p. 1046.

14) Die Wirbellosen des Weissen Meeres. Bd. I, p. 119, 1885.

THECOSOMATA de Blainville

1821. Thecosornata de Blainville, Dict. des Sc. Nat., t. XXXII, p. 271.

1885. Pterocepliala [part.) Wagner, Die Wirbellosen des Weissen Meeres, Bd. I, p. 119.

1886. Eiipteropoda Boas, Spolia Atlantica, p. 14.

The great number of genera, in which the species of the Thecosornata were divided, has
been reduced to eight by Pelseneer ^). These genera belong to three families, which, especially
with respect to the shape of the shell, differ sufficiently from each other. to be distinguished
at first sight. They are Limacinidae, CavoHniidae and CymbuHidae.

The external parts of the body of the Thecosornata : the shape of the foot, of the fins,
of the tentacles, etc, have been described so often and in details, that it does not seem
necessary to repeat what has been said on this subject by Souleyet"), Boas^) and Pelseneer*) —
neither have the general anatomical characters need to be spoken of.

What has been published about the anatomy by van Beneden ^), Gegenbaur ''),
Souleyet '), Boas ■) and others, was still importantly augmented by Pelseneer by an exact
anatomical study of each genus separately ''). Pelseneer gives thirty-four generic names. To
my opinion two other names ought to have been mentioned among these: Anomia Forsk&l
and Gioeiiia Gioëni (both -= Cavolinia Abildgaard). This last genus I can only mention on
the authority of de Blainville (article Hyale in Dict. d. Sc. Nat. XXII) and of Souleyet
(Hist. Nat. Ptérop. p. 33, note i), as I have not had the opportunity to see Gioëni's work
myself. The species of the genus Agadina have been recognised by Pelseneer himself as
Gastropoda-larvae (Streptoneural).

Through these investigations it has been sufficiently proved:

1" that the Thecosornata descend from the BuUoidea,

2" that the Limacinidae are the original forms,

3" that further specialisation with the intention of accommodating to the pelagic way ot

living, has led to the apparent (external) symmetry, which appears in most forms of the

Cavoliniidae and
4" that these two families do not descend from each other, but that the external and internal

characters of the genus Peraclis among the Limacinidae are connected to each other on the

one side by Limacina with the Cavoliniidae, on the other by larval stages of Cyuibtilia

with the Cymbuliidae.

The question in how far there is any connection between the dorsal mantle hole of the
Limacinidae and the ventral one of the Cavoliniidae — which is accompanied by a great many
other differences between the two families — has been spoken of by Souleyet and Grobben.

1) Challenger Report. LXV, p. 5—8.

2) Voyage de la Bonite. VoL II, 1852.

3) Spolia Atlantica. 1885.

4) Challenger Report. LXV, LXVI, 1888.

5) Exercices Zoötomiques. Mém. Acad. Sc. Brux. 1841, Vol. XII, 1839. Mém. sur la Limacina arctica. Op. cit. Vol. XIV.

6) Untersuchungen über Pteropoden und Heteropoden. Leipzig 1885.

7) Challenger Report. LXVI, p. 5 — 37.

SoULEYEï ') regards the representatives of his <^enus Spirialis as being simply Cleodora-ioxm?,
"dont la partie postérieure du corps et de la cocjuille sont contournées en spirale", while
Grobben '), \vh(i thinks that the ventral mantle-hole is the original one, attributes the dorsal
position to the twisting of the visceral mass, but calls the mantle-hole of the Cavolinidae
secondary-ventral.

BoAS ^) was the first who gave an explanation of the connection, mentioned above.

He pointed out, how the Cavolinidae have proceeded from the Limacinidae by a turn
of I So° (in the opposite direction of the hands of a clock) of the hind part of the body, which
has stretched itself with respect to the head part, so that the latter (foot, fins, tentacles, penis,
etc. *) shows the greatest conformity in both the families. But the mantle-hole, the ending of
the intestinal canal, the heart, the efferent duet of the gonad, are differently situated in both
families in so far that the organs which are situated dorsally, ventrally, to the right, or to
the left in the Limacinidae, have their place just in the opposite direction in the Cavolinidae.

Bo.\s fully explained his assertion, so that I can refer to his work for further particulars.
Pelseneer °) modified Boas' theory somewhat. According to him, it is not the hind part that
has made a turn of i8o° with respect to the fore part (or vicc versa), but both the parts have
turned 90° in different directions with respect to each other. This had to be proved by the
retractor muscle. According to Boas "), part of this muscle, running to the right of the
oesophagus, is a new formation, while Pelseneer, referring to Fol "'), just regards this branch
as being the original, which also radiates in both the fins.

At the same time Pelseneer showed the affinity between the Limacinidae and the
Cymbuliidae, which had not been discovered by any investigator before him. Here, too, the
revolving process of 180° has taken place. Though the full-grown animals of the Cymbuliidae
seem to show very little resemblance with the Limacinidae, yet there are a great many important
points of conformity with Peraclis in respect to the (left-handed) larvae of the first mentioned family.

Family L Limacinidae.

1847. Limacinidae Gray, the Genera of recent Mollusca, Proc. Zool. Soc. London, p. 203.
1853. Hyalidae (part.) d'Orbigny, in Ramon de la Sagra, Histoire physique, politique et

naturelle de l'ile de Cuba, vol. I, p. 70.
1859. Spiralidae Chenu, Manual de Conchyliologie, vol. I, p. 113.
1863. Liuiacinacea Troschel, Das Gebiss der Schnecken, Bd. I, p. 50.

The animals, representing this family, are nearly always very small. A dimension of a
few mm. may be called considerable already, and there are only two species which strike the

i) SouLEYET. Voyage de la Bonite. Vol. II, p. 20S — 215.

2) Harn- und Geschlechtsorgane der Cephalopoden. Arb. Zool. Inst. Wien. Tomé 5, p. 63.

3) Spolia Atlantica. p. 19 — 22.

4) But not the central nerveus system, as Boas says.

5) Challenger Report. LXVI, p. 28—37.

6) Spolia Atlantica. p. 22, note I.

7) Arch. de Zoölogie, exp. 1875, Vol. IV. Sur Ie développement des Ptéropodes. pi. IV, fig. 43, 44.
SIB0G.1-EXPEDITIE Lir.

lO

eye by a somewhat larger size. To the smallness of the animals it must be attributed tliat
before Boas and Pelseneer only a few attempts have been made, to bring some order in the
confusion, which also reigned here.

SouLEYET ^) distinguished two genera: Limacina without operculum, and Spirialis with
operculum. Since, however, an opercuhmi has been found -) in Limacina helicina, the only
representative of the genus Limacina, as Souleyet understood it, now the difference between
the two genera cannot exist any longer. Boas *) brought all the species of the family together
to the single genus Limacina, but Pelseneer's researches *) have proved that there are two
very distinct genera : Limacina and Pcraclis.

The study of the collection, brought home by the Challenger, has given occasion to
Pelseneer to distinguish °) ten species. Two of them, however, must be considered rather
doubtful, as the animals have never been found as yet, and only the empty shells were brought
up from the bottom of the sea {Limacina triacaniha and Limacina hclicoidcs). So we cannot
state with certainty, whether we have to do with "Pteropoda".

As the Siboga Expedition has onlj- caught three species of Limacina, and as of the
other species I could only study Limacina hclicina, I have not been able to observe the specifïc
differences, given by Pelseneer. The three species of the Siboga-material, however, are clearly
distinct from each other.

Of the genus Peraclis two species have been known up to now, though of Pcraclis
bispinosa *) only the empty shells have been found. The Siboga Expedition has added two new
species, and a variety of an already known one.

With a few words I must draw the attention to the well-known fa et, that the shell of the
Limacinidae is left-coiled, while the animals themselves possess the organisation of right-handed
Gastropoda. The shell is in this case ultra-dextral which, as one knows, also occurs in some
species of the genus Ampullaria. The spira of a right-coiled shell may become more and more
flattened, then the shell may be rolled up in one plane, and finally it appears in the place
where originally the umbilicus has been, which now takes the place of the spira. The operculum
does not take any part in this process, consequently it retains the direction of its coils.

According to Souleyet '), the operculum of the Limacinidae is right-handed, except in
one case, where it is figured in situ in Limacina bulimoides ").

In Sars's paper ^) too, the operculum of Limacina helicina, '^Spirialis'' balea and

1) Hist. nat. d. MoU. Ptévop. p. 60 — 65.

2) Saks, Mollusca regionis aicticae Xorvegiae, Chiistiania, 1S78, p. 32S, pi. 29, iig. ie.

3) Spolia atlantica, p. 39.

4) Chall. Rep. LXV, p. 9—15.

5) Ibid., p. 17—37-

6) Ibid., p. 36.

7) Voyage de la Bouite, MoUusques, pi. XIII.

8) Op cit. pi. XIII, fig. 36.

9) Mollusca regionis arcticae Xorvegiae, pi. 29, figs. \e, 2(/, 3«'.

1 1

'^Spirialis' retrover sus is coiled to the right, while Boas figured ^) that of "■ Limacina' reticulata
as a right-handed spiral. Pelseneer corrected ') this, but he sa\s abcnit tlie operculum of
Limacina that it exhibits a right-coiled direction ^).

In reality the opcrcuhim of Pcraclis is left-coiled, as it has been represented by d'Orhignv,
long before Souleyet.

Pelseneer stated ') afterwards that the opercuhnn ol Limacina retrovei'sa was left-handed,
a fact which, after my own researches, holds good in the three species of the Siboga-material
too. The opercuhim of Limacina inflata is figured PI. I, tig. i. In the two other species it
shows a more elongated shape.

In Peraclis the opercuhnn exhibits the same left-handed direction.

The beginning of its spiral is turned to the umbilicus (false spira).

Limacina Cuvier.

1817. Limacina Cuvier, Le Règne animal, t. II, p. 380.

1823. Hetcrofiisiis Fleming, On a reversed species of Fusiis, Mém. Wern. Soc, p. 498.

1824. Spiratella de Blainville, Dict. d. Sci. Nat., t. XXXII, p. 284.

1836. Heliconoides (part.) d'Orbigny, Voyage d. I'Amér. mér., t. V, p. 174.
1840. Spirialis (part.) Eydoux et Souleyet, in: Revue Zool., t. III, p. 235.
1842. Helicophora Gray, Synopsis of the contents of the British Museum, p. 59.
1844. Scaea Philippi, Fauna Molluscorum utriusque Siciliae, p. 164.
1861. Protomedea (part.) Costa, Microdoride mediterranea, p. J^.

1869. Enibolus Jefifreys, British conchology, vol. V, p. 114.
1885. Limacina (part.) Boas, Spolia atlantica, p. 39.

I. Limacina iiijlata (d'Orbigny).

1836. Atlanta inflata d'Orbigny, Voyage dans FAmérique meridionale, vol. V, p. 174, pi. 12,

figs. 16 — 19.
1840. Spirialis r ostralis Eydoux et Souleyet, Description sommaire de plusieurs Ptéropodes

nouveaux ou imparfaitement connus, Revue Zoölogique, vol. 3, p. 236.
1850. Limacina inflata Gray, Catalogue of the Mollusca in the collection of the British Mus.,

Prt. II, Pteropoda p. 31.
1852. Limacina scaphoidea Gould, The Mollusca and Shells of the U. S. Exploring Expedition,

p. 485, pi. 51, fig. 602.
1861. Protomedea elata O. G. Costa, Microdoride mediterranea, p. 74, pi. 11. fig. 5.

1870. Evibolns r ostralis Jeffreys, Mediterranean Mollusca, Ann. and Mag. Nat. Hist., ser. 4,

vol. 6, p. 86.
1882. Protomedea r ostralis Fischer, Sur le faune Malacologique abyssale de la méditerranée,

Comptes rendus, vol. XCIV, p. 120.
1889. Embolus inflatus Dall, in: Bullet. U. S. Nat. Mus., n" ij , p. 80.

Living animals:

Stat. 35. 8° o'.3 S., iió°59'E. i spec.

Stat. 66. Betvveen Bahuluwang a. Tambolungan, south of Saleyer. 2 spec.

Stat. 95. 5°43'.5N., ii9°4o'E. Sulu Archipelago. 2 spec.

1) Spolia atlantica, pi. III, fig. 39^.

2) Chall. Rep. LXV, p. 33.

3) Ibid., p. 16.

4) Suv la dextrorsité de cei-tains Gastropodes dits "sénestres". Comptes rendus, iSgi, t. CXII, p. 1016.

12

Stat. Ii6. o°58'.5N., I22°42'.5 E. West of Kwandang Bay, entrance. i spec.

Stat. 138. East coast of Kajoa Island. i spec.

Stat. 141. 1° o'.4 S., I27°25'.3E. Batjan. 20 spec.

Stat. 143. 1° 4'.5 S., I27°S2'.6E. i spec.

Stat. 144. North of Damar Island. i spec.

Stat. 146. 0° 36' S., 128° 32'./ E. 2'/2 miles north of eastern Widi Group, i spec.

Stat. 148. 0° 17

Stat. 177'. 2° 30'

Stat. 185. 3° 20'

Stat. ï8g\ 2° 22

Stat. 194. i°53

Stat. 203. 3° 32

Stat. 210'. 5° 26'

Stat. 243. 4° 30'

Stat. 245. 4° 16'

6 S., I29°I4'.5E. 23 spec.

S., 129° 28' E. 2 spec.

S., 127° 22'. 9 E. Manipa Strait. i spec.

S., 126° 46' E. 5 spec.

.5 S., 126° 39' E. I spec.

.5 S., 124° i5'.5 E. I spec.

S., 121° i8' E. I spec.

.2 S., 129° 25' E. 20 spec.

.5 S., I30°I5'.8E. 2 spec.

Thi.s species seems to live in the whole East-Indian Archipelago, which was explored
by the Siboga. On some stations it was very abundant.

Some specimens exhibit a brown spot on the last whorl of the shell, just above the
aperture. Besides, the animals differ a little in size.

I have not found the "lame vitree", mentioned by Souleyet ^).

The animal has no dorsal lobe on the fin.

*2 "). Limacina lestieurii (d'Orbigny).

1836. Atlanta lesueurii d'Orbigny, Voyage dans l'Amérique meridionale, vol. V, p. 177.

pi. XX, figs. 12 — 15.
1836. Atlanta rangii d'Orbigny, Ibid., p. 176, pi. XII, figs. 25 — 28-
1840. Spirialis ventricosa Eydoux et Souleyet, Description sommaire de plusieurs Ptéropodes

nouveaux on imparfaitement connus, Revue Zoölogique, vol. III, p. 236.
1850. Limacina ventricosa Gray, Catalogue of the Mollusca in the collection of the British

Museum, prt. II, Pteropoda, p. 32.

1886. Limacina Icsnenrii Boas, Spolia atlantica, p. 46. PI. III, figs. 33 — 34.

1887. Limacina rangii Munthe, Pteropoder i Upsala Universitets Zoologiska Museum, Bihang

till K. svenska vet.-akad. Handlingar, Band 13, Afd. IV, n" 2, p. 8, figs. 12 — 13.

Limacina lesueurii has been found off Batavia (Bo.-vs) ') and again by the Challenger
Expedition 2°56'N., 134° 11' E. (north of New Guinea). However, the Siboga did not succeed
in finding it again.

As I had no occasion to study any specimen I cannot say whether d'Orbigny is right,
who erected a new species for his Atlanta rottmda *). The figures of the shell indeed seem to
refer to Limacina lesueurii^ and perhaps it is only a variety of the type, as Souleyet ")
regarded it. But d'Orbigny says in the text, that the shell of Atlanta rotnnda is "a peine
ombiliquée", and the margins are "épais"; the operculum "circulaire, formé de lignes

i) Voyage de la Bonite, vol. Il, p. 216. PI. XIII, fig. 7 — 8.

2) The species, not obtained by the Siboga are marked by an asterisk.

3) Spolia atlantica, p. 47.

4) Voyage dans l'Amérique meridionale, vol. V, p. 175, pi. XII, figs. 20 — 24.

5) Voyage de la Bonite, vol. Il, p. 219.

13

concentriques vers Ie centre". If this proves to be truc, we must entertain some doubts whether
Atlanta rotiuida is even a "Pteropod". Munthe has regarcled it as [a distinct species (see
the list above of synonyms) but it was referred by Pelseneer ^) to the genus '^ Agadina\

As to Atlanta rangii, it differs so very slightly from Limacina leszteurii, that it cannot
be regarded as a distinct species, as Munthe (see above) ") has done. The umbilicus is only
somewhat wider, quite as in Spirialis ventricosa.

3. Limacina trochiformis (d'Orbigny).

1836. Atlanta trochiformis d'Orbigny, Voyage dans l'Amérique meridionale, vol. V, p. 177,

pi. XII, figs. 29—31.
1840. Spirialis trochiformis Eydoux et Souleyet, Description sommaire de quelques Ptéropodes

nouveaux ou imparfaitement connus, Revue Zoölogique, vol. III, p. 237.
1850. Limacina trocliiformis Gray, Catalogue of the Mollusca in the collection of the British

Museum, Prt. II, Pteropoda, p. 33.
1852. Limacina naticoides Rang, Histoire naturelle des Mollusques Ptéropodes, pi. X, figs. i — 2.

Living animals:

Stat. 59. 10° 22'. 7 S., 123° 16'. 5 E. Western entrance Samau Strait. 2 spec.

Stat. 121. i°33'.7N., 124° 46'.$ E. Menado. i spec.

Stat. 138. o°23'.8N., 127° 29' E. East-coast of Kajoa Island. i spec.

Stat. 148. o'^i7'.6S., I29°I4'.5E. x spec.

Stat. 203. 3°32'.5 S., I24°I5'.5E. i spec.

Stat. 214. 6° 30' S., 121° 55' E. 2 spec.

Nothing can be remarked about the geographical distribution of this species. It seems
rarer than Limacina inflata.

No tentacular lobe on the dorsal margin of the fin.

4. Limacina bulimoides (d'Orbigny).

1836. Atlanta bulimoides d'Orbigny, Voyage dans l'Amérique meridionale, vol. V, p. 179,

pi. XII, figs. 36—38.
1840. Spirialis bulimoides Eydoux et Souleyet, Description sommaire de quelques Ptéropodes

nouveaux ou imparfaitement connus. Revue Zoölogique, vol. III, p. 238.
1850. Limacina bulimoides Gray, Catalogue of the Mollusca in the collection of the British

Museum, Prt. II, Pteropoda, p. 34.
1889. Limacina (Heter of usus) bidimoides Dall, in: Bullet. U. S. Nat. Mus., n° 37, p. 80.

Living animals:

Stat. 138. o°23'.8N., 127° 29' E. East coast of Kajoa Island. i spec.

Stat. 143. 1° 4'.5 S., i27°52'.6E. i spec.

Stat. 148. 0° I7'.6 S., 129° 14'. 5 E. 10 spec.

Stat. 243. 4° 3o'.2 S., 129° 25' E. 2 spec.

Like the foregoing species.

Some slight difference in size among the individuals may be noticed.

No tentacle-Hke lobe on the anterior fin margin.

i) Challenger Report LXV, p. 40.

2) It may be remarked, that the figure of Munthe shows the margins of the shell thickened, while d'Orbigny says : "bords tranchants".

14
A n a t o m i c a 1 R e m a r k s.

Our knowledge about the anatomy of the genus Liinacina being considerably enriched by
Pelsexeer's researches '), I have scarcely anything to add to what has been published by this
able investigator. As he has done, so have I studied Lbiiacina helicina (from Matotschkin Strait).
The shell, the fins of the anima! , its radula and jaws have been figured by Sars ") (radula also
by BoAs)^), the tentacles and the whole visceral anatomy have accurately been described by
Pelseneer, to whose figures I can moreover refer *).

The chief point is the fact, that the shell is sinistral (ultra-dextral), while the anima!
exhibits a right-handed organisation.

The gonad consists of very numerous small follicles, occupying the whole initial portion
of the visceral mass. The penis includes a rounded horn piece, as in all "Pteropoda". — On
the left side of the stomach I have found a gastric caecum, which is perhaps the same as the
"bile duet", mentioned by Pelseneer (PI. I, fig. 2).

The central nervous system is asymmetrical, the right portion of the visceral mass
being larger than the left. Pelseneer was the first who discovered this asymmetry, not only
in this case, but in all the genera of the Thecosomata.

The supra-oesophageal commissure is attached to the median side of the right cerebral
ganglion (Pl. I, fig. 3 C).

Though I have often sought for the second pedal commissure, I have not found it.
Only once I could see a small nerve (?) parting from the front of one of the pedal ganglia
and directed towards the other, but even in this case I have not been able to decide whether
this was a real commissure, or perhaps onh- a part of the very thin connective layer on
the ganglia.

The otocysts are easily visible, owing to a brown pigment at the margins.

As to the nerves which part from the central nervous system I noted two nerves
proceeding from the anterior part of the cerebral ganglia (not one, as Pelseneer has figured)").
In any other respect 1 agree entirely with Pelseneer ; only the right pallial nerve was stronger
than the left (Pl. I, fig. 3 A, B, C).

Auditory nerves I have not seen.

Peraclis Forbes (emend.).

1836. Heliconoides (part.) d'Orbigny, Voyage dans l'Amérique meridionale, vol. V, p. 174.
1840. Spirialis (part.) Eydoux et Souleyet, Description sommaire de plusieurs Ptéropodes

nouveaux ou imparfaitement connus, Revue Zoölogique, vol. III, p. 235.
1844. Peraclc Forbes, Report on the MoUusca and Radiata of the Algean Sea, and on their

distribution, considered as bearing on Geology, Rep. Brit. Ass. 1843, p. 186.

1) Challengei' Rep. LXVI, p. 7 — 11. It must have been a lapsus cnlaiiil^ that the authov says (p. 7): "head distinct", this
being indistinct.

2) MoUusca regionis arcticae Noivegiae, pl. 29, fig. I, pl XVI, fig. 17. Notwithstanding Sars deuies the existence of
jaws in Limacina^ saying (p. 328): "maxillae nuUae".

3) Spolia atlantica, pl. III, fig. 22.

4) Op. cit. Pl. I, figs. 1—8.

5) Op. cit. s. Pl. 1, fig. 7.

i847- Campylonans Gray, A List of the Genera of recent Mollusca, their synonyms and types,
Proc. Zool. Soc. Lond., 1847, p. 149.

1858. Euromus A. and li. Adams, The Genera of recent Mollusca, vol. II, p. 613.

1876. Limacina (part.) Jeffreys, New and peculiar Mollusca of the family Eulimidae and other
families of Gastropoda, as vvell as of the Pteropoda procurcd in the "Valorous"
Expedition, Ann. and Mag. Nat. Hist. (4), vol. XIX, p. 337.

I. Peraclis retictilata (d'Orbigny) var. minor n. v. (PI. I, fig. 4).

Living animal:

Stat. 243. 4°3o'.2S., 129° 25' E. 3 spec.

Description; Shell almost entirely agreeing with the description, given by Pelseneer ^).
Four whorls, rapidly increasing, the last turn very large ; reticulation hexagonal, becoming less
marked towards the aperture, where it entirely disappears. The prolonged rostrum is bent forward.
Colour: Yellowish-red (spirit-specimen).
Dimensions: Height 1,25 mm.; max. diameter i mm.
O p e r c u 1 u m : Transparent, with six coils, rounded, left-handed.

Animal: Head on a short proboscis, lips united ventrally; tentacles without sheath, and
symmetrical. Fins broad, truncated, without tentacular lobe, posterior lobe of the foot broad at the base.
It is only with hesitation that I can make up my mind to regard the specimens of the
Siboga-Expedition as a variety of the type. Comparing accurately the description and the
figures of Pelseneer with the foregoing, there may be found only the following differences :
I. The chief one is the difference in dimensions. Pelseneer notes: maximum length 4 mm.;
diameter 2,3 mm. The specimens of d'Orbigny ~) and those of Souleyet ^) which were
2 mm. high, have been regarded by Pelseneer as young individuals, though d'Orbigny
notes, notwithstanding the small size, four whorls in the spiral, and moreover that the
reticulation is often not seen towards the aperture.
II. The operculum has six coils, not four. It corresponds entirely with Boas' figure ^), if this
be regarded as seen from the inside.

III. The apex is more obtuse than in Pelseneer's figure, the first turn being almost in the
same plane as the second.

IV. The inner lip of the aperture is very thin.

Though readily consenting that the differences from the type are very insignificant, I
do not believe that the Siboga-specimens are quite identical with it. Particular attention must
be paid to the genus Peraclis^ being the most important among the Thecosomata.

2. Peraclis rissoides n. sp. (PI. I, figs 5, 6, 11, 13, 14).

Living animal:

Stat. 243. 4°3o'.2S., 129° 25' E. i spec.

Description: .Shell as in Peraclis reticiilata var. minor ^ that is to say : apex obtuse,

1) Challenger Rep. LXV, p. 34, pi. I, figs. 7 — 8.

2) Voyage dans l'Amérique meridionale, vol. V, p. 178.

3) Voyage de la Bonite, vol. II, p. 220. PI. 13, figs 17 — 19.

4) Spolia atlantica. PI. III, fig. Sgl"'s.

■ i6

surface reticulated, while the hexagonal sculpture disappears towards the aperture. But there
are four and a half vvhorls, in er e as ing more regularly. The rostrum being breken off,
I could not make out its form. No umbilicus.

C o 1 o u r : Yellowish-red (spirit-specimen).

Di men si ons: Height 1,75 mm.; max. diam. 1,40 mm.

O p e r c u 1 u m : Transparent, rounded, left-handed, six coils.

Animal: Ouite as the above described variety of Pcraclis rcticiilata. A strongly
developed "balancer" on the right side of the mantle makes me think, that the rostrum must
be long, probably curved in the same direction as in Peraclis retictdata var. minor.

The characters of the shell differ sufficiently from that of Pcraclis reiic7ilaia to regard
this form as a distinct species. Indeed, the shell is smaller, having four and a half whorls in
its spire; moreover these whorls increase gradually.

3. Peraclis moluccensis n. sp. (PI. I, figs. 7, 8, 9, 10).

Living animal :

Stat. 243. 4°3o'.2S., 129° 25' E. i spec.

Description: .Shell transparent, surface without reticulation, but with slightly marked
rays on the deep suture, especially on the last whorl. Spire extremely short, four and a
half whorls. The iirst turns rolled up in the same plane, and entirely covered (shell being
seen from the aperture) by the ver}- strongly bulging last whorl, which exhibits on the dorsal
margin of the aperture a tooth, directed towards the apex, and curved in the direction of the
last whorl ; this tooth is supported by a thick rib. Between this rib and the suture the rays are
especially streng. Rostrum straight, not curved. No umbilicus.

C o 1 o u r : None, the animal being seen through the thin shell (spirit-preservation).

Dimensions: Height 0,80 mm.; max. diam. 1,20 mm.

O p e r c u 1 u m : Glassy, rounded, about four whorls, left-handed.

Animal: The only information I can give about the animal is, that this species undoubtedly
belongs to the genus Peraclis, as I have noted a short proboscis, the lips, surrounding the
mouth, uniting ventrally, and two symmetrical tentacles of the same size and without sheath.

A short time after the single specimen had been figured, the shell was unfortunately
quite crushed into small fragments, and the animal became so seriously damaged, that I had
to abstain from further investigation. What I could observe about the animal, has been
mentioned above.

Though greatly regretting the accident which prevented me from giving a more complete
description, I hope the peculiarities of the shell will be sufficiënt to distinguish this species from
other forms.

Peraclis mohiccensis has evidently some affinity with Peraclis bispinosa (Pelseneer) ^) but
differs from it in being much smaller '), in the very depressed spire, and in the tooth which

1) Challenger Rep. LXV, p. 36, figs 9 — 10.

2) The dimensions of P. hispïnosa are : length 7,5 mm,, diameter 6 mm.

17

is stronoer anil not dircctecl outwards. Nor is "" Spirialis diversa" Monterosato ') identical with
one of tht: abovc-nained forms.

The smoothness of the slicll shows that the reticulation does not occur always among
the species of this genus.

Anatomical Notes.

The organisation of the genus Peraclis^ being known by a single representative (P.
reticulata) until now, has only been studied by Pelseneer '). The differences from Limacina
are very striking, and these differences connect Peraclis with the Cymbuhidae. This is a fact of
great importance and of the utmost value, as regards the phylogenetic affinities among the
genera of the Thecosomata '').

I sliall restrict mj-seU" to my own researches.

The head is situated on a short proboscis (PI. I, fig. ii), rising from the dorsal margin
of the fins; the h'ps unite ventrally, as well as dorsally, and have thickened walls ; tentacles
very small, symmetrical, situated on the same transverse hne, and without sheath.

F o o t : The posterior lobe of the foot is short, with broad base, and scarcely notched
in the middle of its free margin. The fins are broad, without tentacle-Hke lobe; at their distal
extremity they e.xhibit a shallow sinuosity; the ventral margin of the fins is situated more
distally than the dorsal one, the inclination of the swimming organs with regard to the body
therefore differing about go° from that of Limacina.

Alantle: The pallial gland exhibits transverse bands, and was found to be symmetrical*).
In the shield, seen from within, I noticed an elongated organ, which is perhaps the heart. On
the right side of the mantle rises a long "balancer", whose insertion is somewhat pyriform.

(The description of the mantle refers only to Peraclis rissoides^ other forms I have
not examined in this respect).

Digestive Tract: There are two salivary glands, visible by a whitish colour on the
brown oesophagus. At the entrance of the digestive tract I noticed two lateral jaws, especially
developed towards the ventral side. Each jaw consists of four transverse series of horny teeth ;
the teeth towards the median and ventral side carry numerous hooks, more obtuse and less
in number [Peraclis reticulata var. minor ^ PI. I, fig. 12). The difference between the ventral
teeth and the lateral ones is most distinct on the first transverse row and becomes gradually
less distinct on the following series. Every row is inserted on a strong transverse muscular
band. To my opinion, the jaws of Peraclis differ from those of Limacina in being stronger ^).

As to the radula, I have not noticed anything remarkable; it is quite the same as in Limacina.

The oesophagus is extremely short. Further information may be found in Pelseneer's
work. The extreme smallness of the animals did not permit me to study their organisation at

i) Nuova revista, etc, Atti Ac. se. lett. ed arti, vol. V, p. 50. A good description with figures is given by Locard Exp.
SC. Tiavailleui' et Talisman, Moll., vol. II, p. 29, pi. I, figs. 4 — 6.

2) Challenger Rep. LXVI, p. 11 — 12.

3) Ibid., p. 28—37.

4) Pelseneer (op. cit.) remarks that the pallial gland is asymmetrical in Peraclis reticulata.^ as in Limacina.

5) Sars, Mollusca legionis arcticae Norvegiae, PI. XVI, fig. \ib.

SIBOGA-EXPEDITIE I.II. 3

/-,

full account. Neither did I study the generative organs, nor the excretory apparatus. The organ
on the roof of the palHal cavity, which is probably the heart, has been mentioned ah-eady.

Central nervous system: It differs very strikingly from that of Limacma and is
almost identical, as regards the ganglia, with that of Cymbulia. I can only confirm Pelseneer's
discovery, after having studied the nervous system of Peraclis rissoides (PI. I, fig. 14). The
pedal and cerebral ganglia are symmetrical, but instead of the asymmetrical visceral mass,
occurring in Limacina, there are "three ganglia, the two lateral of which are symmetrical and a
little smaller than the central one". With these words I agree entirely, only I found scarcely
any difference in size between the three visceral ganglia.

Furthermore I have seen (i) a tentacular nerve issuing from the anterior part of the
cerebral ganglia (B), (2) the nerves to the fins and to the posterior lobe of the foot (A),
proceeding from the pedal ganglia, (3) a nerve proceeding from the right visceral ganglion (like
Pelseneer, I could not find one on the left), and (4) two visceral nerves from the median visceral
ganglion, one of them issuing almost median, the other from the right side of the ganglion (A, 4, 5).

The buccal ganglia, close to the oesophagus, are connected by a commissure.

Geographical Distribution.

Peraclis reticiilata^ first discovered by d'C^rbigny ^), who considered it to be a Heteropod,
and several times found again by other investigators, seems to be very rare, though living over
a vvide area. Living animals vvere caught in the Pacific Ocean (d'Orbigny, Souleyet, Bo.\s) and
in the Mediterranean, (Pelseneer, Oberwimmer), while the occurrence of the species in the Atlantic
is somewhat doubtful, though the empty shells (without reticulation) have been recorded through
deep-sea dredgings "), even from the North-Atlantic. The Challenger Expedition found Peraclis
reticulata in the Atlantic only represented by deposit shells.

lts occurrence in the East-Indian i\rchipelago was to be expected, as it has been found
in the Pacific Ocean (though in the eastern part) '') by d'Orbigny, Boas (Chierchia Expedition)
and Pelseneer (Challenger Expedition). Pelagic animals being generally distributed over wide
areas, the variability in characters among the individuals of the same species is greater than
in organisms, strictly localised by their mode of life. An attentive examination of a number of
individuals from different stations will probably show some variations.

Peraclis bispinosa *), recorded from the Atlantic by the Challenger Expedition and from
the Mediterranean'), is only known by its shell. The same is true of "-Spirialis diz'ersa" '^j
Monterosato, found in the Atlantic.

The two new species in the Siboga-material, Peraclis rissoides and Peraclis inoliiccensis^

1) Voyage dans l'Amérique méridiouale, vol. V, p. 174, figs. 32 — 35, 39.

2) As to the synonymy, 5ee Belseneer, Chall. Rep. LXV, p. 32.

3) Souleyet ^Voyage de la Bonite, vol. II, p. 221) has not noted a distuict locality; he says only: "dans l'Océan Pacifique".

4) Pelseneer, Chall. Rep., LXV, p. 36, pi. I, figs. 9 — 10.

5) Oberwimmer, in Denkschr. K. Akad. Wiss. Wien, Bd. LXV, p. 5S9.

6) Nuova revista etc, in .\tti Acad. se. lett. ed arti, vol. V, p. 50. This species was referred by Pelseneer to Peraclis
bispinosa (though with some doubt, as the description of de Monterosato is insufficiënt). It seems, however, a well defined species
of Peraclis (though with deep umbilicus!), according to Locard, Expéditions scient. Travailleur et Talisman, Moll. test., vol. II,
p. 29, pi. 1, figs. 4 — 6.

19

secm 1(1 be rare, each of thcm beinj^ represented by a single specimen only. It is a remarkable
fact, however, ihal the live specimens of Pcraclis were obtained from one single station,
otï Banda (Stat. 243).

Limacina triacaiitJia ') (Fischer) is perhaps a species of Pcraclis too.

Appendix to the Limacinidae.

To the family Limacinidae some forms have been referred by several natiiralists,
which do not even belong to the Thecosomata. The "species" were based on minute shells,
which sometimes exhibited a right-handed spire. Most of these "new" forms, however, had
already disappeared, when Pelseneer began his task of criticizing the species of the "Pteropoda".
This author showed ") that species of the genus '^ Agadina' were only larvae of streptoneural
Gastropods, while at the same time he designated "'Limacina turritelloides' Boas ^), as a
young Ti'iforis.

Having found among the spoils of the Siboga several sinistrorsal shells, evidently not
belonging to "Pteropods", I think it to be of some use to discuss them.

I. "■Limacina iiirritalloides" Boas.

1887. Limacina iiirritelloides Boas, Spolia atlantica, p. 49 — 50, Pi. III, fig. 35.

1898. Simisigera tiirritclloides Oberwimmer, Denkschr. Kais. Akad. VVien, Bd. LXV, p. 592.

Living animals:

Stat. 148. o°i7'.6S., 129° 14'. 5 E. 4 spec.

Stat. 222. 6° 10' S., 125° 35'. 5 E. 6 spec.

It bas been with some doubt that Boas ^), who could only study the shell, has regarded
this form as a Limacina. With much authority however, this opinion was rejected by
Pelseneer ^), who also had only empty shells at his disposal. According to him this "■Limacina
turritelloides" was a young Triforis, identical with " Sinusigera perver sa'^ Graven ^j. Munthe"),
whose paper appeared only a few months before Pelseneer's work, maintained the species of
Boas as being a distinct form.

The study of the animals themselves has shown me, that they are real larvae. I noticed
a broad foot and a four-lobed velum. The operculum, inserted to the posterior end of the
foot, has a large nucleus, the coils have a right-handed direction and increase slowly.

The type on which the genus Agadina Gould ") has been based, was referred by
Pelseneer ") to Limacina antarctica, though Gould's figure exhibits a right-handed spiral.
Gould himself erected the genus " Agadijia' for his " Lhnacina cucullata\

i) Jouin. de Conch., vol. XXX, p. 49.

2) Challenger Rep., LXV, p. 37 — 40.

3) Spolia atlantica, p. 49 — 50, PI. 111, fig. 35.

4) Op. cit. s. p. 40.

5) Ann. Soc. Malacol. Belg., vol. XVIIl. p. 26.

6) Pteropoder i Upsala Universitets Zoölogiska Museum, Bihang til K. Svenska Vet. Akad. Handlingar. Bd. 13, afd. IV, n" 2.

7) U. S. Exploring Expedition under the commaud of Wilkes, 1852. Vol. XII, p. 486, PI. LI, figs óoirt, /».

8) Challenger Report, L.W, p. 37.

20

After 15 years A. Adams ') described as two new species of Agadina, two forms, the
shells of which are, however, really sinistral.

The Challenger-material has given occasion to Pelseneer to show, that these "species"
of Adams (and still another Agadina-iorm found by the Challenger) were only Gastropod larvae.

The Siboga has also collected some "species" of Agadina.

1. '^Agadina''' stivipsoni A. Adams.

1867. Agadina stiDipsoni A. Adams, Description of new species of Shells from Japan, Proc.
Zool. Soc. London, 1867, p. 309, pi. XIX, fig. 23.

Living animals:

Stat. 213. 5° 54.5 S., 120° i9'.2 E. I spec.

Stat. 215^ 6° 30' S., 121° 55' E. 2 spec.

Stat. 225. Near the Lucipara Islands. i spec.

Stat. 243. 4°3o'.2S., 129° 25' E. 2 spec.

Stat. 245. 4° i6'.5 S., i30°i5'.8E. i spec.

Stat. 282. 8°25'.2S., i27°i8'.4E. i spec.

Stat. 304. Lomblen Island. i spec.

The bell-shaped margins of the shell are slightly brown-coloured. I stated, as Pelseneer
has done too, that this Agadzna-form is only a larva, as I found a four-lobed velum on the
head, and a broad foot, which carries the operculum.

2. '^Agadina' n. sp. (Pelseneer).

1888. Agadina n. sp. Pelseneer, Pteropoda Thecosomata. Challenger Rep. LXV, p. 39,
pi. I, figs. 15 — 16.

Stat. 157. o°32'.9S., i30°i4'.6E. i spec.
Stat. 213. 5°54'.5S., 120° 19'. 2 E. i spec.
Stat. 225. Near Lucipara Islands. i spec.

I myself did not study the animal, but according to Pelseneer, it carries on its head
a four-lobed velum and is doubtless a Gastropod-larva.

Another Agadiua-ionn may be mentioned here.

3. "■Agadifia" n. sp. (PI. I, fig. 15).

Stat. 215". 6°3o'S., 12 1° 55' E. i spec.

The shell is left-handed. entirely transparent, with somewhat thickened margins; suture
well marked, deep ; three whorls, spire somewhat projecting beyond the last whorl. Deep
umbilicus, as in "'Agadina ' sfiinpsoni^ but without rays.

Operculum, cjuite as in "■ Agadina'' stimpsoni: left-handed, many turns slowly increasing.

Animal with a four-lobed velum on its head.

Dimensions: Height 0,75 mm.; max. diam. i mm.

i) Proc. Zool. Soc. London 1S67, p. 309.

2 I

The shells of these larval fonns are minute, left-handed, sometimes transparent; so
there is some resemblance with the shells of Limacinidae, hut the thickened margins of
" Agadina" form the difference. Besides, the opercuhim in '^ Agadina' is horny and not thin
and glassy as in the Limacinidae; it has a largc nucleus, left-handed, and is attached
more strongly to the foot by means of a knob. Another difference from the Limacinidae
is the fact that the opercuhmi, very distinctly concave at the outside, is circular and not
more or less semilunar.

H. SiMROTH ^) made already known several larvae with a left-handed shell, about which
it is very difficuk to decide to what genus they must be referred. Perhaps they belong to
marine streptoneural Gastropods with a right-handed spire, but the initial portion of which is
coiled to the left, as it has been suspected by Pelseneer -). The operculum is left-handed, and
besides, the beginning of its spiral is turned to the columella, as occurs in ultra-dextral forms.

Family IL Cavoliniidae.

1841. Hyalidac (part.) d'Orbigny, in: Histoire physique, politique et naturelle de l'ile de Cuba,

par Ramon de la Sagra, Mollusques, vol. I, p. 70.

1842. Cavolinidae d'Orbigny, Paleontologie frangaise, Terrains cretacés. vol. II, p. 4.
1842. Cleodoridae Gray, Synopsis of the contents of the British Museum, p. 92.

1854. Hyalacacea Troschel, Beitrage z. Kenntn. der Pteropoden. Arch. f. Naturgcsch., Jahrg.

XX, p. 196.
1856. Hyaleidae (part.) Woodvvard, Manuel of the MoUusca (2nd Edit. p. 348).
1869. Cliidae JefFreys, British Conchology, vol. V, p. 118.
1875. Ortlioconques Fol, Sur Ie développement des Ptéropodes, Arch. d. Zool. exp., sér. i,

vol. IV, p. 177.
1885. Hyalaeidae Boas, Spolia atlantica, Bidrag til Pteropodernes Morfologi og Systematik samt til

Kundskaben om deres geografiske Udbredelse, Vidensk. Selsk. Skr., 6. Raekke.IV, i.p. 51.
1888. Cavoliniidae Pelseneer, Challenger Rep. LXV, p. 41.
incl. Cuvieridae Gray, 1842 =^ Tripteridae Gray, 1S50.

This family formerly included many more genera, than really belong to it. D'Orbigny
(see the list above) classed all the Thecosomata, with which he was acquainted, among his
Hyalidae (also Cymóulia and Liniacitia) and Souleyet ^) referred to his "familie des Hyales"
also Limacina and "■ Spirialis\ while Woodward (see above) included in his family: Euribia
Rang (= Halopsyche Bronn), Cymóulia and Tiedemannia Delle Chiaje [^ Gleba Forskal).

Boas and Pelseneer, however, have defined more strictly the limits of the Cavoliniidae.
The forms, composing this family, are characterised by their external, calcareous, bilaterally-
symmetrical shell *), which is not coiled, but in some cases straight, in others provided with a

1) Die Gastropoden dev Plankton-Expedition 1895.

2) Challengei- Rep. LXV, p. 40.

3) Histoire naturelle des Mollusques Ptéropodes, p. 32.

4) Some asynimetry in the shell is found in Clio (Styliola) siihula., iu "■Clcodora''' Schulei Munthe (Pteropoder i Upsala
Universitets zoologiska Museum, Bihang till K. Svenska Vet. Akad. Handlingar, Bd. 13, afd. IV, n" 2, p. 18 — ig, fig. 15), and in
'■Pleuropus hargcri" Verrill (Catalogue of Marine Mollusca added to the fauna of the New England region, during the past ten years,
Transactions Connectie. Acad. vol. V, prt. 2, 1882, p. 555).

dorsally curved apex. An embryonic shell (Fol) is often disdnguished from the rest. The animal
has a ventral pallial cavity and a dorsal cohimellar muscle. The flexure of the intestine is
ventral. The anus situated on the left sidc; in the central nervous system the left portion
of the visceral mass is more developed than the right.

The affinity of the Cavoliniidae with the Limacinidae has been discussed before.

Three distinct genera can only be admitted among the various species, though formerly
a great number of generic titles has been used ').

These genera are : Clio. Cuvicrina and Cavoliiiia.

The sfenus Clio inckides four snborenera :

Creseis^ HyalocyU.\\ Sfv/iohr, Clio fs. sfr.).

Cuvierina was regarded by Gray ") as a genus, representing a separate family; however,
it clearly belongs to the CavoHniidae.

Cavoliiiia consists of two subgenera :

Diacria, Cavoliiiia fs. sfr.).

According to Pelseneer, fourteen species of Clio may be distinguished. However, I cannot
regard Clio conica as a distinct form, as I shall explain further on. Munthe has described a
new species of Clio (see note i), so that the number of species is fourteen. Six of them were
obtained by the Siboga. I cannot discuss the specific distinctness of the species which form the
subgenus Clio fs. str.J^ as I could only observe two species.

As to the genus Cuvierina it includes only a single species. This species was reprssented
in the Siboga-material by a few empty shells only.

The eight species of Cavoliiiia are all included in the Siboga-collection.

New fornis have not been found.

Clio Linné.

1756. Clio Browne, The civil and natural History of Jamaica, p. 386.

1767. Clio Linné, Systema naturae, ed. 12, vol. I, prt. 2, p. 1094.

18 10. Cleodora Péron and Lesueur, Histoire de la familie des Mollusques Ptéropodes, Ann.

Mus. Hist. Nat. Paris, vol. XV, p. 66.
1825. Styliola Lesueur, in: DE Blainville, Manuel de Malacologie, p. 655.
1828. Crcseis Rang, Notice sur quelques Mollusques nouveaux appartenant au genre Cleodora,

et établissement et monographie du sous-genre Creseis, Ann. d. Sc. Nat. sér. i,

vol. XIII, p. 302.
1837. Balantniin Benson, Notice on Balantiiiui, a Genus of the Pteropodous MoUusca, Journ.

Asiat. Soc. Bengal, vol. VI, p. 151.
1875. Hyalocylix Fol, Sur Ie développement des Ptéropodes, Arch. d. Zool. Exp., vol. IV, p. 177.

Subgenus Creseis Rang fs. sfr.J.

1828. Creseis (part.) Rang, Notice sur quelques Mollusques nouveaux, etc, Ann. d. Sc. Nat.

sér. I, vol. XIII, p. 302.
1828. Styliola (part.) Auctorum.

i) As to the different generic names, see Pelseneer, Cliall. Rep. LXV, p. 41.

2) Catalogue of the Mollusca in the collection of the British Museum. Prt. II, Pteropoda, p. 23.

23

1 . Clio (Creseis) virgula (Ransr.)

1828. Creseis virgula, clava Rang, Notice, etc. Aiin. d. Sc. Nat. sér. i, vol. XIII, p. 316 — 317,

pi. XVII, fig. 2, 5.

1829. Creseis conica, unguis, cornucopiae, caligula I-^schscholtz, Zool. y\.tl., Heft III, p. 17 — 18,

pi. XV, figs. 3—6.

1830. Creseis striata Delle Chiaje, Memorie sulla storia e notomia degli animali scnza vertebrc,

pi. LXXXII, fig, 12.
1836. Hyalaea corniformis d'Orbigny, Voyage dans l'Amérique meridionale, vol. V, p. 120,

pi. VIII, fig.s. 20 — 23.
1850. S/yliola virgula Gray, Catalogue of the Mollu.sca in the collection of the l^ritish Museum,

prt. II, Pteropoda, p. 17.
1850. Styliola corniforinis Gray, Ibid., p. 18.

1852. Cleodora virgula Souleyet, Voyage de la Bonite, Zool., vol. II, p. 196, pi. VIII, figs. 18 — 25.
1852. Cleodora munda, placida, falcata Gould, The Mollusca and Shells of the U.S. Exploring

Expedition under the command of WiLKES, p. 489 — 490, PI. LI, figs. 607 a, b,

606 a, 608 a.
1869. Creseis conica A. Costa, Pteropodi del golfo di Napoli, Rendiconto d. reale Accad. d.

Sci. Napoli, p. 58.

1872. Styliola vitrea Verrill, Recent Additions to the Molluscan fauna of New England and

the adjacent waters, etc. Amer. Journ. Sci. and Arts, vol. III, p. 284, pi. VI, fig. 7.

1873. Creseis conoidea A. Costa, Pteropodi della Fauna del Regno di Napoli, p. 17, pi. IV, fig. 6.
1879. Cleodora jiexa Pfefter, Bericht uber die von S. M. SCHIFF "Gazelle" und Dr. JAGOR

gesammelten Pteropoden, Monatsber. d. k. pr. Ak. d. Wiss. Berlin, p. 241, figs. 15 — 16.
1888. Clio (Creseis) virgula Pelseneer, Chall. Rep. EXV, p. 48.
1888. Clio (Creseis) conica Pelseneer, Ibid., p. 50, pi. II, figs. i — 2.

Living animals:

Stat. 2. 7°27'.5 S., 113° 8'.5 E. 3 spec.

Stat. 35. 8° o'.3 S., 116° 59' E. 2 spec.

Stat. 36. 7° 38' S-, 117° 31' E. 6 spec.

Stat. 75. 4°57'.4S., 119° 2'.8 E. 4 spec.

Stat. 96. Pearl-bank, Sulu Archipelago. 12 spec.

Stat. 98 — 99. 6°9'N., 120° 21' E. ± 20 spec.

Stat. 106. Kapul Island, Sulu Archipelago. ± 70 spec.

Stat. 109. Pulu Tongkil, Sulu Archipelago. 10 spec.

Stat. iio. 4° 34' N., 122° o' . E. 6 spec.

Stat. 112. 3° i' N., 122° 2' E. 3 spec.

Stat. W]\ i°i5' N., 123° 37' E. 18 spec.

Stat. 121. Menado. i spec.

Stat. 128. 4° 27' N., i25°25'.7E. 10 spec.

Stat. 130. 5° o' N., I25°26'.5E. ± 20 spec.

Stat. 136. Ternate. ± 25 spec.

Stat. 138. Kajoa Island. ± 20 spec.

Stat. 143. 1° 4'.5 S., i27°52'.6E. i spec.

Stat. 144. Damar Island. ± 20 spec.

Stat. 146. o°36' S., i28°32'.7E. 2 spec.

Stat. 148. o°i7'.6S., 129° 14'. 5 E. 5 spec.

Stat. 149. Gebé Island. 5 spec.

Stat. 156. o°29'.2 S., 130° 5'.3 E. 2 spec.

Stat. 165. Daram Island. ± 50 spec.

Stat. 169. Atjatuning. 8 spec.

Stat. 172. Between Gisser and Ceram-Laut. 5 spec.

Stat. 174. Waru Bay (Ceram). 4 spec.

24

Stat. 177". 2° 30' S., 129° 28' E. 8 spec.

Stat. 184. Kampong Kelang. 2 spec.

Stat. 185. Manipa Strait. 8 spec.

Stat. 193. Sanana Bay, Sula Besi. 4 spec.

Stat. 194—197. i°53'S., 127° E. 8 spec.

Stat. 203. 3°32'.5S., i24°i5'.5E. 6 spec.

Stat. 205. Lohio Bay, Buton Strait. 10 spec.

Stat. 210'. 5° 26' S., 121° 18' E. 2 spec.

Stat. 215". North-point of Kabia Island. 15 spec.

Stat. 220. Pasir Pandjang, Binongka. ± 20 spec.

Stat. 223. 5°44'.7S., 126° 27'. 3 E. 17 spec.

Stat. 224. 5° 34' S., 127° 4' E. 5 spec.

Stat. 225. Near the Lucipara Islands. 2 spec.

Stat. 276. 6°47'.5 S., i28°4o'.s E. 2 spec.

Stat. 315. Sailus Besar, Paternoster Islands. 16 spec.

From this long list of stations it results that this species is most abundant in the East-
Indian Archipelago. Together with the following species, it is certainly by far the most common
form in this region.

The numerous variations in form, according to which many different titles have been
used, will be discussed further on.

2. Clio (Creseis) acicula (Rang).

1828. Creseis acicula Rang, Notice sur quelques Mollusques nouveaux, etc. Ann. d. Sc. Nat.

sér. I, vol. XIII, p. 318, pi. XVII, fig. 6.

1829. Creseis aciis Eschscholtz, Zool. Atl. Heft III, p. 17, PI. XV, fig. 2.

1836. Hyalaea acicidata d'Orbigny, Voyage dans l'Amérique meridionale, vol. V, p. 123,

pi. VIII, figs. 29 — 31.
1850. Styliola recta Gray, Catalogue of the Mollusca in the collection of the British Museum,

prt. II, Pteropoda, p. 18.
1852. Cleodora acicula Souleyet, Voyage de la Bonite, Zool., vol. II, p. 194, pi. VIII, figs. 10 — 17.
188S. Clio (Creseis) acicula Pelseneer, Chall. Rep. LXV, p. 51.

Living animals:

Stat. I. 7° 27'. 5 S., 113° 8'. 5 E. • ± 30 spec.

Stat. 2. 7° 25' S., 113° 16' E. 7 spec.

Stat. 35. 8° o'. 3 S., 116° 59' E. ±15 spec.

Stat. 37. Sailus Ketjil, Paternoster Islands. rh 40 spec.

Stat. 47'. Batu Putih, entrancc Bay of Bima. i spec.

Stat. 50. Bay of Badjo, West-coast of Flores. +: 25 spec.

Stat. 66. Between Bahuluwang and Tambolungan. 45 spec.

Stat. 71. Makassar. 11 spec.

Stat. 89. Pulu Kaniungan Ketjil. 12 spec.

Stat. 96. Pearl-bank, Sulu Archipelago. 1 1 spec.

Stat. 99. 6° 7'.5 N., 120° 26' E. 18 spec.

Stat. 104. Sulu-harbour, Sulu Island. ± 30 spec.

Stat. 106. Kapul-island, Sulu Archipelago. 20 spec.

Stat. 109. Pulu Tongkil, Sulu Archipelago. 15 spec.

Stat. iio. 4° 34' N., 122° o' E. 5 spec.

Stat. 112. 3° r N., 122° 2' E. 7 spec.

Stat. 117'. i°i5' N., 123° 37' E. 12 spec.

Stat. 118. i°3S' N., 124' 2'6'.2'E. 1 spec.

25

Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta
Sta

122. i°58'.5 N., 125° o'.5 E.

125. Sawan, Siau Island.

128. 4° 27' N., r25°25'.7 E.

130. 5° o' N., i25°26'.5E.

136. Tcniatc.

138. Kajoa Island.

141. 1° o'.4 S., i27°25'.3 E.

143. 1° 4'.5 S., i27°52'.6E.

146. o°36' S., i28°32'.7E.

148. 0° ij'.C) S., 129° 14'. 5 E.

149. Fau, West-coast of Gebé Island.
157. o°32'.9 S., 130° h'.óE.

165. Daram Island.

169. Atjatuning, West coast of New-Guinea.

172. Between Gisser and Ceram-Laut.

174. Waru Bay, North coast of Ceram.

177'. 2° 30' S., 129° 28' E.

185. 3° 20' S., I27°22'.9E.

189'. 2° 22' S., 126° 46' E.

193. Sanana Bay, East coast of Sula Besi.

194—197. i°53' S., 127° o' E.

203. 3°32'-S S., i24°is'.5 E.

205. Lohio Bay, Buton Strait.

210'. 5° 26' S., 121° i8' E.

213. Saleyer.

2I5'*. North-point of Kabia Island.

217. 6°4o'.6 S., i23°i4'.7E.

220. Pasir Pandjang, West coast of Binongka.

223. 5°44'-7 S., i26°27'.3E.

224. 5° 34' S., 127° 4' E.

225. Near the Lucipara Islands.
243. 4°3o'.2 S., 129° 25' E.
245. 4°i6'.s S., i30°i5'.8E.
252. W^est-side of Faam Island.
276. 6°47'.s S., i28°4o'.5 E.
282. 8°25'.2 S., i27°i8'.4E.

315. Sailus Besar, Paternoster Islands.

4 spec.

2 spec.

3 spec.
Az 70 spec.

18 spec.
17 spec.

14 spec.
± 30 spec.

2 spec.

5 spec.
5 spec.
5 spec.

± 15 spec.
33 spec.

1 spec.

3 spec.
± 25 spec.

4 spec.
10 spec.

2 spec.
10 spec.
27 spec.
25 spec.

12 spec.

5 spec.

3 spec.
25 spec.

± 35 spec.

9 spec.

± 40 spec.

13 spec.

4 spec.
± 40 spec.

9 spec.

15 spec.
12 spec.

± 50 spec.

A great number of specimens were caught; this species is perhaps more abundant than
the foregoing one.

Crcscis virgula and Creseis aciiu/a e.xhibit man)- variations, and a large number of
distinct "species" has been distinguished, as may be seen from the list of synonyms. Souleyet,
however, ah'eady affirmed ') that the ditïerence between virgula and aciatla consisted only in
the curvature of the shell, and Boas '), after examining a great number of both species from
the Indian and Pacific Ocean, was of opinion that the forms virgula and acicicla were only a
single species. The dorsally curved shell of virgula passes so gradually into the straight shell of
acicula, that it is almost impossible to say, where the limits are between the two species (See
in his work, pi. 6, fig. 94).

1) V^oyage de la Bonite, Zoölogie, vol. II, p. 196.

2) Spolia atlantica p. 61.
SIBOOA-EXPEDITIE LH.

26

Pelseneer ') regarded conica as a transitional form between virgtila and acicula. The
dlfferences among his three species are mentioned here summarily:

I. Shell. A. Initial portion of a dark brown colour.

a. Shell itself with very marked dorsal curve-, transverse

diameter rapidly increasing Clio virgiila.

' b. Shell slightly curved ; the transverse diameter increases

gently and uniformly Clio conica.

B. Posterior extremity whitish.

Shell long, slender, straight Clio acicula.

II. Animal. A. Oesophagus very long; for that reason stomach and liver

situated much behind Clio virgtila.

B. Oesophagus short.

a. Liver distinct Clio conica.

b. Liver much reduced Clio acicula.

I. As to the shell, I have seen a very great number of forms, and I agree with Boas, that
the limits between virgula and acicula are scarcely visible. The torms corniforniis, virgula.,
conica., clava, acicula merge into one another. Besides, many specimens of acicula have a
brown-coloured embryonic .shell.
II. I did not find the oesophagus in conica and in acicula short, neither can I attach any
great importance to the liver, which is present, even in the very long a«V?//i3:-specimens. I
think that the anatomical differences vary gradually with the curvature of the shell.

The difference between clava and acicula^ though slight, is somewhat greater than
between the other forms. Though clava was referred by Souleyet, by Boas and by Pelseneer
to acicula, I believe it belongs to virgula.

Therefore I have referred all the forms with a curved shell (corniformis., virgula, conica)
to the species virgula. Also the very short straight form clava.

On the other hand I have referred the specimens with very long, slender, straight shells to
the species acicula. Styliola vitrca was referred by Boas to Crcseis virgula, by Pelseneer to Creseis
conica. The figure of Verrill shows the fins rounded, but this is most probably a mistake.

The e.vtremity of the shell in virgula and acicula shows two very slight constrictions,
the anterior of which, tolerably distinct in the first species, gradually disappears in acicula
(See Boas, Spol. atl. figs. 40 — 33).

Subgenus Hyalocylix Fol.

1828. Creseis {part.} Rang, Notice sur quelques Mollusques nouveaux etc, Ann. d. Sc. Nat.,

sér. I, vol. XIII, p. 302.
1875. Hyalocylix Fol, Sur Ie dcveloppement des Ptéropodes, Arch. d. Zool. Exp., sér. i,

vol. IV, p. \j-j.
1875. Styliola {part.) Auctorum.
1875. Cleodora {part.} Auctorum.

i) ChalL Kep. LXV, p. 50.

3- Clio (Hyalocylix) striata (Rang).

1828. Crcscis striata R;in_q;, Noticc sur qiiclques MoUusqucs etc, Anii. d. Sc. Nat., sér. i,

vol. XII, p. 315, pi. XVII, fig. 3.

1829. Creseis comprcssa Eschscholtz, Zool. Atl., Heft III, p. 17, pi. XV, fig. 7.

1830. Creseis sonata Delle Chiaje, ïMcmorie suUa storia e notomia dcgli animali senza vertebre,

pi. LXXXII, fig. 9.
1836. Hyalaca striata d'Orbigny, Voyage dans rAmérique meridionale, vol. V, p. 122,

pi. VIII, figs. 23 — 25.
1850. Styliola striata Gray, Catalogue of the Mollusca in the Collcction of the British Museum,

prt. II, p. 18.
1852. Cleodora striata Souleyet, Voyage de la Bonite, vol. II, p. 191, pi. VIII, figs. i — 4.
1854. Creseis phaeostoma, inonotis Troschel, Beitrage zur Kenntniss der Pteropoden, Arch. f.

Naturg., 20''' Jahrg. p. 206 — 208, pi. VIII, figs. 5 — 9.
1888. C/io (Hyalocylix I striata Pelseneer, Chall. Rep. LXV, p. 54, pi. II, fig. 3.

Living animals:

Stat. I. 7°27'.s S., 113° 8'.5 E. i spec.

Stat. 2. 7° 25' S., 113° 16' E. 6 spec.

Stat. 89. Pulu Kaniungan Ketjil. 2 spec.

Stat. 96. Pearl-bank, .Sulu Archipelago. 3 spec.

Stat. 1 10. 4° 34' N., 122° o' E. 3 spec.

Stat. 118. i°38' N., 124° 28'. 2 E. 2 spec.

Stat. 128. 4° 27' N., i2S°25'.7E. i spec.

Stat. 130. 5° o' N., 125° 26'. 5 E. 2 spec.

Stat. 136. Ternate. 28 spec.

Stat. 138. East coast of Kajoa Island. 2 spec.

Stat. 141. 1° o'.4 S., i27°25'.3E. 2 spec.

Stat. 143. 1° 4'.5 S., 127° 52'. 6 E. 2 spec.

Stat. 144. Damar Island. i spec.

Stat. 146. o°36' S., i28°32'.7E. i spec.

Stat. 165. Daram Island. 318 spec.

Stat. 168. North of Sabuda Island. 14 spec.

Stat. 169. Atjatuning, West coast of New-Guinea. 30 spec.

Stat. 174. Waru Bay, North coast of Ceram. i spec.

Stat. I77\ 2°3o' S., 129° 28' E. 10 spec.

Stat. 185. 3° 20' S., i27°22'.9E. 9 spec.

Stat. 289". 2°22' S., 126° 4.6' E. 2 spec.

Stat. 205. Lohio Bay, Buton Strait. 5 spec.

Stat. 243. 4° 30'. 2 S., 129° 25' E. I spec.

Stat. 276. 6°47'.5 S., i28°4o'.5 E. 2 spec.

Stat. 304. Lomblen Island. i spec.

This species, though occurring in the whole East Indian Archipelago, was very abundant
at some stations.

Among the specimens of stat. 169, one e.xhibited a pecuHarit}', which has been figured
on PI. II. fig. 16. The shell was somewhat constricted near the end, bluntly pointed, and not
curved at all. Iransverse ridges were scarcely visible on the posterior half of the shell. At the
end, I remarked three or four longitudinal, irregular ridges. As to the animal, the fins, the
posterior lobe of the foot and the two tentacles as well as the pallial gland did not show any
difference from these organs in a normal Hyalocylix; I believe, therefore, it is only an anomaly.

28

The embryonic shell of this species is caducous ; it has been figured, however, by Fol ')
and by Pelseneer "). Like the latter I have seen it on an adult specimen, but as may be seen
from the figure (PI. I, fig. 17), I remarked two constrictions behind the partition, vvhich
separates the embryonic portion from the rest of the shell.

Troschel (see the list of synonyms) has described and figured two "species", which to
my opinion must be referred to Clio striata. Both these forms are young stages. Troschel
noted in " Creseis phaeostonia' the anus on the right side, but from his description it may be
inferred, that he has mistaken the genital duet (if this really exists already in such young
forms) for an intestine.

Subgenus Styliola Lesueur.
1825. Styliola Lesueur, in: DE Blalwille, Manuel de Malacologie, p. 655.

4. Clio (Styliola) subuia (Qoy and Gaimard).

1825. Styliola recta Lesueur, in: DE Blainville, Manuel de Malacologie, p. 655 (name only).

1827. Cleodora subiila Qoy et Gaimard, Observations Zoologiques faites a bord de l'Astrolabe,

etc, Ann. d. Sc. Nat., sér. i, vol. X, p. 233, pi. VIII Z?, figs. i — 3.

1828. Creseis spuiifera Rang, Notice sur quelques Mollusques nouveaux, etc, Ann. d. Sc.

Nat-, sér. i, vol. XIII, p. 313, pi. XVII, fig. i.

1828. Creseis subuia Rang, Ibid., pi. XVIII, fig. i.

1836. Hyalaea subuia d'Orbigny, Voyage dans l'Amérique meridionale, vol. V, p. 119,

pi. VIII, figs. 15 — 19.
1850. Styliola subuia Gray, Catalogue of the MoUusca in the collection of the British Museum,

prt. II, Pteropoda, p. 17.
1852. Cleodora subulata Souleyet, Voyage de la Bonite, Zoölogie, vol. II, p. 192, pi. VIII, figs. 5 — 9.
1852. Styliola subulata Fischer, Manuel de Conchyliologie, p. 437.

1888. Clio (Styliola) subuia Pelseneer, Chall. Rep. LXV, p. 57.

1889. Cleodora (Styliola) subulata Dall, in Buil. U. S. Nat. Mus., vol. XXXVII, p. 80.

Living animals:

Stat. iio. 4° 34' N., 122° o' E. 12 spec.

Stat. 128. 4° 27' N., I25°25'.7E. i spec.

Stat. 148. 0° iy'.6 S., 129° i4'.5 E. i spec.

Stat. I77''. 2° 30' S., 129° 28' E. 3 spec

Stat. 185. 3° 20' S., I27°22'.9E. I spec.

Cho subiila has been recorded by the Siboga Expedition only from the Celebes Sea and
the Ceram Sea. It does not seem to be very abundant.

Subgenus Clio Linné.

1767. Clio Linné, Systema Naturae, i2'li ed., p. 1094.

18 10. Cleodora Péron et Lesueur, Histoire de la Familie des Mollusques Ptéropodes, Ann.
Mus. Hist. Nat. Paris, vol. XV, p. 66.

1829. Balantinin Anonymous, Journ. Roy. Inst., vol. XV, p. 220.

1) Sur Ie développeraent des Ptéropodes, Arch. d. Zool. Exp., sér. i, vol. IV.

2) Challenger Rep. LXV, p. 55, pi. 11, fig. 3.

29

*5- Clio balantinm (Rang).

1829. Balantmin recurvum Anonymous, Journ. Roy. Inst., vol. XV, p. 220, pi. VII, fig. 107.
1834. Cleodora bala?itium Rang, Magasin de Zool. 1834, pi. XLIV.

1836. Hyalaea balantium d'Orbigny, Voyage dan.s rAméiiquc meridionale, vol. V, p. 116,

pi. VII, figs. 1—4.

1837. Balantinm bkarmatiwi Benson, Notice on Balanliuin, a Genus of the Pteropodous

Mollusca, Journ. Asiat. Sec. Bengal, vol. VI, p. 151.
1852. Cleodora infata Souleyet, Voyage de la Bonite, vol. II, p. 188, pi. VII, figs. 17 — ig.
1S88. Clio balantium Pelseneer, Chall. Rep. LXV, p. 61.
1889. Cleodora reciirva Dall, in: Bullet. U. S. Nat. Mus., n" 37, p. 82.

A young specimen was found by the Challenger, north of New-Guinea (2° 5 6' N., 134° i i'E.)
I have not found this species among the spoils of the Siboga.

6. Clio pyraiiiidaia Linné {iion Rang).

1767.
1813.

1825.
1836.

1852.
1852.

1853-

1877.
1880.

Clio pyramidata Linné, Systema Naturae, I2th Ed., p. 1094.

Hyalaea lanceolata Lesueur, Mémoire sur quelques espèces d'animaux mollusques et

radiaires recueillis dans la Méditerranée prés de Nice, Nouv. Bullet. d. Science par

la Soc. Philom de Paris, vol. III, p. 284, pi. V, fig. 3.
Cleodora brownii de Blainville, Dict. d. Sc. Nat. pi. 59, fig. i.
Hyalaea pyramidata d'Orbigny, Voyage dans I'Amérique meridionale, vol. V, p. 113,

pi. VII, figs. 30—32.
Cleodora lanceolata Souleyet, Voyage de Ia Bonite, vol. II, p. 179, pi. VI, figs. 17 — 25.
Cleodora exacnta Gould, The Mollusca and Shells of the U. S. Exploring Expedition

u. the comm. of WiLKES, vol. XII, p. 488, pi. LI, fig. 605.
Cleodora lainartinieri d'Orbigny, Histoire physique, politique et naturelle de l'ile de

Cuba, par Ramon de la Sagra, Mollusques, vol. II, p. 83.
Cleodora labiata Sowerby, in Reeve, Conchologia iconica, vol. XX, Pteropoda, fig. 26.
Cleodora martensii Pfeffer, Die Pteropoden des Hamburger Museums, Abhandl. d.

Naturw. Ver. Hamb., Bd. VII, p. 95, pi. VII, fig. 16.

Living animals:

9° 3'.4 S., 119° 56'. 7 E. 5 spec.

io°22'.7 S., i23°i6'.5E. I spec.

o°34'.6N., 119° 8'. 5 E. 8 spec.

6° 4'.iN., 120° 44' E. I spec.

0° 11' S., 127° 25' E. I spec.

1° o'.4 S., 127° 25'. 3 E. I spec.

2° 30' S., 129° 28' E. I spec.

2° 40' S., i28°37'.sE. I spec.

3° 20' S., i27°22'.9E. 2 spec.

3° 32'. 5 S., 124° 15'. 5 E. 2 spec.

5° 40'. 7 S., i20°45'.5 E. 7 spec.

5°54'.5 S., i20°i9'.2E. i spec.
Near the Lucipara Islands. 5 spec.

4° 30'. 2 S., 129° 25' E. 2 spec.

6° 47'. 5 S., 128° 40'. 5 E. I spec.

Stat. 52

Stat. 59

Stat. 88

Stat. 102

Stat. 1 39

Stat. 141

Stat. 177

Stat. 178

Stat. 185

Stat. 203

Stat. 211

Stat. 212

Stat. 225

Stat. 243,

Stat. 276

This species, almost cosmopoHtan, was also found at many stations. It is by far the
most common form among the species of Clio (s. slr.J.

30

BoAS distinguished ^) three variations, aiigiista, lata and convexa. The first of these forms
has been figured by d'Orbigny ") under the name of "var. i?", while lata was indicated by
this author as "var. A'\

According to Boas, angusta occurs in the North Atlantic (60° — 40° N.B.) and in the
east part of the Pacific, while lata is found in the Atlantic (40° N.B. — 30°S.B.), Mediterranean,
Indian Ocean, China Sea and in the west part of the Pacific. I cannot, however, attach any
importance to this geographical distribution, as in the Siboga-material the two forms angusta
and lata occurred together {angtista : stat. 59, 102, 139, 177^, 185, 203, 211, 276; lata: stat. 52,
88, 141, 178, 211, 212, 243).

The variety convexa (southern |)art of the Indian Ocean and South-Atlantic, according
to BoAS) exhibits such a slight difference from lata, that to my opinion it must be referred to
this form (cf the series of figures, given by Boas, 1. c). The only difference which holds good,
is the smaller size of convexa. The Siboga Expedition has not found it.

7. Clio citspidata (Bosc).

1802. Hyalaca cnspidata Bosc, Histoire naturelle des Coquilles, vol. II, p. 238 (241 ?), pi. IX,

figs- 5—7-
1820. Hyalaea triciispidata Bowdich, Elements of Conchology, pi. VI, fig. i.
1830. Clt'odora lessoiiü Rang, MS., in: LessON, Voyage autour du Monde de la Coquille,

vol. II, prt. I, p. 247, pi. X, fig. I.
1833. Cleodora cnspidata Qoy et Gaimard, Voyage de TAstroIabe, Zoölogie, vol. II, p. 384,

pi. XXVII, figs. 1—5.
1852. ? Cleodora qiiadrispinosa '^) Rang, Histoire naturelle des Mollusques Ptéropodes. pi. V, fig. 6.
1888. Clw cnspidata Pelseneer, Chall. Rep., LXV, p. 66.

Empty shells :

Stat. 95. 5°43'.5N., ii9°'4o' E. i spec.

Stat. 118. i°38' N., i24°28'.2E. i spec.

Stat. 211. 5° 40'. 7 S., I20°45'.5 E. 2 spec.

This species, found abundantly by Lesson (see the note) on the West coast of Australia,
has been recorded by the Siboga Expedition from a few stations only. It was moreover only
represented by empty shells.

The figure given by Woodward ') does not represent, as this author says, '■^Cleodora"
pyramidata, but Clio cnspidata. '

A n a t o m i c a 1 R e m a r k s.
The anatomy of the genus Clio has been studied several times, and after the publications

i) Spolia atlantica, p. 70 — 73, pi. 6, figs. 96 — 97.

2) Voyage dans rAméiique meridionale, vol. V, pi. VII, figs. 25 — 32.

3) This species, already veferred to by Lesson (Voyage de la Coquille, vol. II, pit. i, p. 24S), is piubably the same as Clio
cnspidata., though this suggestion cannot be made with absolute confidence. According to Lesson, the shell "présente quatre angles et
par conséquent quatre faces, qui distants a leur base et tres ouverts, finissent en une point aigué et un peu contournée", while the fins
of the animal are "soudés en avant par un petit lobule arrondi".

4) A Manual of the Mollusca, pi. XIV, fig. 33 (2<i Ed.).

of P. J. \\x Beneden'), Souleyet"), Gegenbaur''), Boas *) and Pelseneer"), it seems to me of no
use to discuss the anatom\- fvilly, as the various researches, which com]jlete each otlier, have
been already sufficiently treated b)- Pelseneer, who at the same time demonstrated the
phvlooenetic affinities of the subgenera.

Crcsris shows much resemblance with Liiiiacimi and is tlie most primitive subgenus of
Clio. This is not only shown by the tentacular lobe on the fin, with which also some species
of Limacina are provided, but also b)- the tentacles, the left of which is ver)- small and scarcely
visible, which agrees with the one that is found in Limacina. The left tentacle is somewhat
larger in Hyalocylix^ Styliola and Clio (s. str.) but even in this last subgenus it does not nearly
attain the dimensions of the right one. I must observe, however, that I could only study two
species of Clio (s. str.)^ so that m\- researches are not complete in this respect. Clio pyraiiiidata
and Clio C2ispidata (Le)'den Museum) were only at my disposal. In this two species I remarked
between the tentacles a triangular lobe, directed forward ; it has been already noted by Souleyet.

As to the foot, the fins, the mantle and the pallial gland, I entirely refer to Pelseneer.
Also with regard to the jaws, the radula, and the salivary glands.

In all the species of the genus CV/ö, examined by me, I found a caecum, entirely
concealed in the liver, and opening at the right side of the stomach. In Clio (s. str.) it is
somewhat swoUen at the end. In Clio ciispidata I noticed a curious, bell-shaped organ, strongly
attached to the intestine. Muscular fibres were seen on this bell, and, comparable with a
dapper, a dark, rounded organ was found within. The bad preservation of the specimens did
not allow me to study the structure of this organ ; most probably it is glandular and opens into
the intestine (PI. I, fig. i8).

About the flexure of the intestine, the position of the anus in the various subgenera,
and the anal gland, I have nothing to remark. Gegenbaur's figure ") which represents the
intestine of Clio (Crescis) acicula as curved dorsally, has been reproduced in several works,
but the inaccuracies as to the organisation of this species were carried to the extreme by
Haller "), whose figure is wrong in almost every respect. Hornell's paper "), treating on Clio
(Creseis) acicula^ I could unfortunately not study.

The various dispositions of the heart and kidney have been described by Boas °) ;
I, therefore, refer to his work. Gills are entirely wanting.

The gonad is situated posteriorly ; in Clio ciispidata, however, I have always found it
dorsally to the liver, and somewhat to the right. The duet e.xhibits an elongated swelling, but
its shape varies in the same species, the swelling being more or less pronounced and sometimes
divided into two parts, which is due in all probability to the maturation of the sexual products.

i) Exercices zoötomiques, Mem. Acad. Sci. Brux. vol. XII, 1839.

2) Voyage de la Bonite, Zoölogie, vol. II, p. 164 — 175.

3) Unters. üb. Pterop. u. Heterop., Leipzig, 1S85.

4) Spolia atlantica, p. 54 — 57.

5) Chall. Rep. LXVI, p. 13—16.

6) Unters. üb. Pterop. u. Heterop., pi. II, fig. i.

7) Lehrb. vergl. Anat. p. 261, 1902.

S) .\natomical Description of C-ijv/j-, as a typical Pteropod, Marine Zool., vol. 11, (1S95), p. 19 — 24.
9) Spolia atlantica, p. 28 — 30.

32

To such a temporal enlargement of the efferent duet one must refer, to my opinion,
the "appendice coecal" of Souleyet ^). Once I too found in this species something of the
kind. Like Pelseneer, I did not find in Clio (Creseis) acicula the receptaculum seminis, figured
by Gegenbaur"); I noticed, however, at the "Uterusdrüse" an organ in a similar disposition, as
the receptaculum seminis displays in the ether species (PI. I, fig. 19).

In Styliola this receptaculum seminis is more slender (PI. I, fig. 20), while it is rounded
in Hyalocylix and Cllo (s. str.J. The accessory genital glands are generally very much hardened
in spirit-specimens.

The central nervous system has been accurately described by Pelseneer '), and I agree
with hini in almost every respect. The cerebral and pedal ganglia are symmetrical as in Limacina,
but this is not the case with the visceral ganglia, the left portion being larger than the right
one. According to Pelseneer, this asymmetry is " particularly prominent" in Creseis \ I found
it, however, scarcely indicated in Clio (Creseis) acicula (PI. II, fig. 21). In this species, as
in Clio pyramidata, particularly examined in this respect, I noticed a small second pedal
commissure. (PI. II, figs. 21 — 22).

I have seen only one tentacular nerve (PI. II, fig. 22), but I have no doubt, that two of
them really exist, as in Liinacitia. I shall not remark anything about other nerves, issuing
from the ganglia ; they are shown in the figures.

The buccal ganglia are united by a rather strong commissure to the cerebral ganglia
(PI. II, fig. 23) und form a single mass.

Cuvierina Boas.

1824. Cleodora (part.) Qoy et Gaimard, Voyage de l'Uranie, Zoölogie, p. 145.

1824. Triptera Auctorum.

1827. Ctivieria Rang, Description de deux genres nouveaux appartenant a la classe des

Ptéropodes, Ann. d. Sc. Nat., sér. i, vol. XII, p. 322.
1886. Ciivicrina Boas, Spolia atlantica, Bidrag til Pteropodernes Morfologi, etc. p. 131.

I. Cuvierina columnella (Rang).

1824. Cleodora obtnsa Qoy et Gaimard, Voyage de l'Uranie, Zoölogie, p. 145, pi. LXVI, fig. 5.
1827. Cuvieria coliunndla Rang, Description de deu.x genres nouveaux, etc, Ann. d. Sc.

Nat., sér. i, vol. XII, p. 323, pi. XLV, figs. 1—8.
1835. Cuvieria oryza Benson, Corrected characters of the genus Cuvieria, and Notice of a

second species inhabiting the tropical Indian Ocean, Journ. Asiat. Soc. Bengal,

vol. IV, p. 698.
1839. Cuvieria obtusa d'Orbigny, Hist. nat. des Canaries, Moll., p. 32.
1850. Triptera colniiinclla Gray, Catalogue of the Mollusca in the Collection of the British

Museum, prt. II, Pteropoda, p. 23.
1850. Cuvieria urceolaris Mprch, Catalogus conchyliorum quae reliquit C. P. KjERULF,

Hafniae, p. 32.

1) Voyage de la Bonite, vol. II, p. 171, note i, pi. XI, fig. 7, z and ;'.

2) Op. S.C. pi. II, fig. 3.

3) Op. s. c. p. 15—16.

JJ

1879. Triptcra columnella, cancdlata Pfefler, Uebersicht der auf S. M. Schiff "Gazelle" und
von Dr. JAGOR gesanimelten Pteropoden, Monatsber. d. k. preuss. Akad. d. Wis-
sensch. Bcrlin, 1879, p. 243, figs. 18 — 19.

1886. Cuvierina columnella Boas, Spolia atlantica, Bidrag til Fteropodcrnes Morfologie, etc,
p. 132, pi. 3, fig. 39; pi. 6, fig. 95; pi. 4, fig. 56.

Empty shells:

Stat. 59. io°22'.7 S., i2 3°i6'.5E. i spec.

Stat. 88. o°34'.6N., 119° 8'.5 E. i spec.

Stat. 95. 5°43'.5N., ii9°4o' E. i spec.

Stat. 100. 6° 11' N., 120° 37'. 5 E. I spec.

Stat. 102. 6° 4'.iN., i2o°44' E. 5 spec.

Stat. 157. o°32'.9S., i30°i4'.6E. i spec.

Stat. 178. 2° 40' S., i28°37'.5E. 3 spec.

Stat. 208. 5° 39' S., 122° 12' E. 2 spec.

Stat. 211. 5°4o'.7 S., 120° 45' E. 2 spec.

Stat. 241. 4°24'.3S., I29°49'.3E. 11 spec.

Stat. 300. io°48'.6 S., i23°23'.iE. i spec.

The only known species of this genus has been recorded from three stations. Only
empty shells have been found.

Boas (see the list of synonyms), who changed the generic name Ciivieria Rang, into
Ctivierina, as the title Cuvieria was already given to other animals before 1827, distinguished
two varieties.

One of them, the var. typica, already known to the discoverer of the species, is elongated,
and the constriction behind the aperture is more marked than in the second form. This is var.
urceolaris, which was regarded by M0RCH (see above) as a distinct species, as Pfeffer has
done too ( Triptera cancellata, see above). This variety is shorter and more bulging. These
two forms, however, are linked by gradual transitions. According to Boas, typica occurs in the
Atlantic, in the Indian Ocean, and East-Pacific, while tirceolaris is found in the China Sea and
the West-Pacific. It was to be expected, that the two varieties should occur together in the
Indian Archipelago. The Siboga-specimens must be referred to iirceolaris, but other specimens
(with the animals in the shells) from Sunda Strait (Utrecht Zoological Museum) belong jsartly to
zcrceolaris, partly to typica.

Remarks upon Anatomy.

I could only study a few specimens from the Utrecht Zoological Museum, two of which
I have sacrificed for anatomical purposes. The same authors who studied the anatom\- of Clio,
have also occupied themselves with the investigation of Cuvierina.

I could state that Cuvierina shows great resemblance with the subgenera Styliola and
Clio (s. str.J. The left tentacle, however, though situated on the same transverse line with the
rio-ht, is much less developed, and very small. The fins agree with those of Clio fs. str.J, but
the posterior lobe of the foot is notched in the middle of its free margin ; this was already stated
by SouLEYET ^) and by Pelseneer -), but the figure of this last author does not show it sufficiently.

1) Voyage de la Bonite, Zoölogie, vol. II, p. 199, pi. XII, figs. 1—3.

2) Chall. Rep. LXVI, p. 16, pi. II, fig. 6.

SIBOGA-EXPEDITIE Lil.

34

The mantle has a balancer on the left side ^), which occurs in all Cavoliniidae. But also
on the right side a lobe of nearlv the same size may be seen.

As to the pallial gland, the jaws, the radula, and the salivary glands, I have nothing
to add to what has been published by Souleyet, Boas and Pelseneer.

I have noticed a gastric coecum, as in all Cavoliniidae; it has not been observed by
Pelseneer. For further Information I can refer to this author. Also with regard to the
disposition and form of the heart and kidney.

The gonad occupies the posterior portion of the visceral mass, as in Clio pxraiuidaia.
From its dorsal side issues an efferent duet, which exhibits the same elongated swelling as in
Clio. I could not clearly perceive a receptaculum seminis at the accessory genital glands
(PI. II, fig. 25). Rang already described and hgured ~) (though very inaccurately) a curious
appendage, which he took for a gill ; several zoologists after him regarded it as the penis.
Most probably it is an accessory copulatory organ, as Souleyet ') and Pelseneer *) suspected.
I have also found it in one case (PI. II, fig. 24). The left branch, which terminates in a point,
exhibits at its base a thick gland (?), already mentioned by Souleyet.

The penis is remarkable through the fact, that the horny stylet is slender, and is situated
in a pouch at the extremity of the copulatory organ.

The central nervous system is like that of Clio. Pelseneer °) affirms that the pleural
ganglia "are here recognisable externally" ; I owe, that I could not distinguish them clearly
from the cerebral or pedal ganglia. The difference betvveen the two halves of the visceral
ganglionic mass is more pronounced than in Clio. The second pedal commissure which I have
noticed, was sómewhat longer than in Pelseneer's figure "). Two nerves proceed from the
anterior part of the cerebral ganglia (PI. II, fig. 26 B). I have seen several nerves issuing
from the pedal ganglia and supplying the fins. From the front of the pedal ganglia rises a
nerve, which, as we shall see further on, also e.xists in Cymbulia. In this case, in Ciivierina.,
I have only seen the nerve of the right ganglion, but most probably there is another on the
left (PI. II, fig. 26 A, 7).

The distribution of the pallial and visceral nerves is the same as in Clio., but according
to my observations, the origins of the three nerves, issuing from the left ganglionic mass are
not so near one another as is shown in Pelseneer's figure °) (PI. II, fig. 26.^^,3,5,6).

The buccal ganglia form a single mass-, the commissures to the cerebral eanelia, and
the nerves issuing irom the approximated ganglia, are the same as in Clio.

Cavolinia ') Abildgaard.

1791. Cavolina Abildgaard, Om Cavolina natans, Anomia tridentata Forskalaei, Skriv. Natur-

hist. Sclsk., Bd. i, Heft II, p. 173.

1792. Cavolinia Bruguicre, Encyclopedie Methodique; HLstorie naturelle des Vers, vol. I.

i) Not on the right side, as Pelseneer states, apparently by a slip of the pen (op. s. c, p. i6).
2) Hist. nat. des Mollusques Ptéi'opodes, pi. IV, figs. lo — II. 3) Voyage de la Bonite, vol. II, p. 201.

4J Op. S.C. p. 17. 5) Chall. -Rep. LXVI, p. 17. 6) Op. s. cit., pi. UI, fig. i.

7) To the list of generic names, given here, must be added, to my opinion : Anomia Forskal (Eaune arabique, p. 124, 1775)
and Giocnia Gioëni (Descvizione di una nuova Famiglia e di un nuovo Genere ni Testacei trovati nel littorali di Catania, Napuli, 17S3).

.o

1797. Rhcda Ilumplireys, Museum Calonnianum.

1801. Hyalaca Lamarck, Système des anim. sans vertèbrcs, p. 139.

18 10. Archonta Dcnis de Montfort, Conchyliologic Systematique, vol. II, p. 50.

1815. Tricla Okcn, Lchrbuch der Zoölogie, vol. I, p. 327.

1825. Flcuropiis Eschscholtz, Bericht über die Zoologische Ausbcutc wahrcnd der Reise von

Cronstadt bis St.-Petcr und Paul, Oken, Isis, Rd. I, p. 735.
1842. Diacria Gray, Synopsis of the contents of the British Museum.
1S59. Orbignvia A. Adams, On synonyms and habitats of Cai'olmui, Diacria and Plcttropiis,

Ann. and Mag. Nat. Hist., ser. III, vol. 3, p. 45.

Subgeniis Diacria Gray.

Hyalaca (pari.) ^Vuctorum.

Pli'iiropus (part.) Auctorum.
1850. Diacria (part.) Gray, Catalogue of the Mollusca in the collection of the British Museum,

prt. II, Pteropoda, p. 10.
1886. Hyalaca, A. Boas, Spolia atlantica, Bidrag, etc, p. 91.

1888. Diacria Pelseneer, Chall. Rep. LXVI, p. 21.

I. Cavolinia (Diacria) trispinosa (Lesueur).

1821. Hyalaca trispinosa Lesueur, in: DE Blainville, Dict. d. Sci. Nat., vol. XXII, p. 82.
1827. Hyalaea inucronata Quoy et Gaimard, Observations zoölogiques faites a bord de

l'Astrolabe, etc, Ann. d. Sci. Nat., sér. i, vol. X, p. 231, pi. VII ^, figs. 1—2.
1832. Hvalaea dcprcssa Bivona, Descrizione di una nuova specie di Jale, etc, Efemeride

scientifiche e litterarie per la Sicilia, p. 57, pi. I, .figs. 4 — 5.
1841. Hvalaea cuspidata Delle Chiaje, Descrizione e notomia degli animali senza vertebre

del Regno di Napoli, pi. CLXXX, figs. i — 2.
1850. Diacria trispinosa Gray, Catal. of the Moll. in the Coll. British Museum, prt. II,

Pteropoda, p. 10.
1850. Diacria inucronata Gray, Ibid., p. 11.

1853. Hyalaea reeviana Dunker, Index Molluscorum, etc, p. 2, pi. I, figs. 17 — 20.
1858. Pleuropus trispinosus A. and H. Adams, The Genera of recent Mollusca, vol. II, p. 611.
1858. Pleuropus viucronatus A. and H. Adams. Ibid.
1879. Pleuropus trispinosa Pfeffer, Uebersicht der auf S. M. Schift" "Gazelle", etc, Monatsber.

Berl. Akad., 1879, p. 236, fig. 6.
1886. Cavolinia trispinosa Locard, Prodrome de conch>-liologie frangaise, p. 22.

1889. Cavolinia (Diacria) trispinosa Dall, in Bullet. U. S. Nat. Museum, XXXVH, p. 82,

pi. LXVI, fig. 115.

Empty shells:

io°22'.7 S., i23°i6'.5E. 2 spec.

o°34'.6N., 119° 8'. 5 E. 2 spec.

5°43'.5 N., II 9° 40' E. 4 spec

6° 11' N., I20°37'.5E. I spec.

6° 4'.i N., 120° 44' E. 4 spec.

5°4o'.7 S., 120° 45'. 5 E. 2 spec.

6° 24' S., 124° 39' E. 5 spec.

Stat. 300. io°48'.6 S., 123° 23'.! E. i spec.

Stat.

59-

Stat.

88.

Stat.

95-

Stat.

100.

Stat.

102.

Stat.

21 1.

Stat.

221.

The fiist name cannot be used, as the title Anomia had been already given to quite other animals: the name Gioinia never occurs again.
I have unfüitunately not been able to see the paper of GioËNi, and I can only mention the title on the authority of de Blainville
(Dict. d. Sci. Nat. vol. XXII, p. 65, note) and Soulevet (Hist. nat. Ptérop. p. 33, note l). But if really GloËNl has used this title, it
has the pviority over Cavolina.

36

It may be remarked that not a single living animal was obtained by the expedition ;
nothing but empty shells have been found. This seems the more striking, since this species,
according to Boas ^) and several other authors, is very abundant in the warm seas.

Hyalaea vmcroiiata, very obscurely described by Ouoy and Gaimard (see the synonyms)
has been regarded as a distinct species by d'Orbigny -). It must be noted, hovvever, that the
type of Ouov and Gaimard, did not differ from that of Lesueur, while d"Orbigny, who found
a somewhat different form, regarded it as the type, described by the zoologists of the
Astrolabe. The "species" of d'Orbigny is somewhat larger, more flattened, and the lateral
points are less divergent and more directed backwards than in Hyalaea trispinosa Lesueur.
Boas ') described two varieties : iiiiiuv, corresponding to the form of Lesueur, and major,
agreeing with Hyalaea niucronata d'Orbigny. As to the differences between these forms, I
must refer to Boas's important paper. But I have feit the truth there is in his words, that it
is in some cases impossible to decide, whether a specimen must be referred to major or to
minor. Neither the extension of the brown colour, nor the distinctness of dorsal grooves are
differences which hold good. Besides, the two varieties are not at all local; they occur together
in the Atlantic and in the Indian Ocean *).

I have referred to major the specimens of stat.; 59, 88, 95, 100, 102; to miiior those
of stat. : 88, 211, 221, 300.

In nearly all the specimens of major the long terminal point was broken off. According"
to Boas, this point is proportionally shorter than in minor.

To show the different forms, I have figured some shells, seen from the dorsal side
(PI. II, figs. 27—31).

2. Cavolinia (Diacria) quadridcnfafa^) (Lesueur).

1821. Hyalaea quadridentata Lesueur in: DE Blainville, Dict. d. Sci. Nat. vol. XXII, p. 81.
1850. Cavolina quadridentata Gray, Catalogue of the Mollusca in the Collection of the British

Museum, prt. II, Pteropoda, p. 8.
1852. Hyalaea inertnis Gould, The Mollusca and Shells of the U. S. Exploring Expedition

under the command of WiLKES, pi. LI, fig. 604.
1877. Hyalaea iiiimita Sowerby, in Reeve, Conchologica iconica, vol. XX, Pteropoda, fig. 9.
1877. Hyalaea inter media Sowerby, Ibid., fig. 10.
1S79. Hyalaea costata Pfeffer, Uebersicht der auf S. M. Schift" "Gazelle" und von Dr. Jagor

gesammelten Pteropoden, Monatsber. d. k. preuss. Akad. Wissensch. Berlin, 1S79. p. 234.
iS88. Cavolinia quadridentata Pelseneer, Chall. Rep. LXV, p. 78.

Living animals:

Stat. I. 7° 27'. 5 S., 113° 8'.5 E. I spec.

Stat. 36. 7° 38' S., 117° 31' E. 2 spec.

Stat. 37. Sailus ketjil. Paternoster Islands. 7 spec.

1) Spolia atlantica, p. 95.

2) Voyage dans r.Amcvique meridionale, vol. V, p. 108, pi. Vil, flgs. 6 — 10.

3) L.C. s.

4) Op. s. c, p. 96.

5) d'Orbigny (Voyage d. r.*\mér. méiid. vol. V, p. 107) when speaking about Hyalaea trispinosa.^ whicli he compares with his
Hyalaea quadridentata (p. 98), gives the name quadiispinosa erroneously to this last species. This must he simply a mistake, and I cannot
admit this name into the list of synonyms.

2>7

Stat. 66. South of Saleyer.

Stat. 89. Pulu Kaniungan ketjil.

Stat. 99. 6° 7'.5N., 120° 26' E.

Stat. 106. Kapul Island, Sulu .\ichipclago.

Stat. 136. Ternate.

Stat. 138. East coast of Kajoa Island.

Stat. 143. 1° 4.5 S., i27°52'.6E.

Stat. 144. Damar Island.

Stat. 14S. o"^ i/'.ó S., i29°i4'.5E.

Stat. 157. o°32'.9S., I30°I4'.6E.

Stat. 165. Daram Island.

Stat. 169. Atjatuning, West coast of New-Guinea. 3 spec.

Stat. 177". 2° 30' S., 129° 28' E.

Stat. 17S. 2° 40' S., i28°37'.5E.

Stat. 185. 3° 20' S., i27°22'.9E.

Stat. 203. 3°32'.5 S., I24°i5'.5 E.

Stat. 215'. Kabia Island.

Stat. 224. 5° 34' S., 127° 4' E.

Stat. 243. 4° 3o'.2 S., 129° 25' E.

Stat. 276. 6°47'.5 S., 128° 40'. 5 E.

Stat. 303. Haingsisi, Samau Island.

Stat. 315. Sailus Besar, Paternoster Islands.

Empty shells :

Stat. 59. 10° 22'. 7 S., i23°i6'.5E.

Stat. 95. 5°43'.5N., 112° 40' E.

Stat. 139. o°ii' S., 127^25' E.

Stat. 165. Daram Island.

Stat. 177^ 2° 30' S., 129° 28' E.

This species is a very common form in the whole East-Indian Archipelago. In all the

specimens the dorsal ribs on the shell are very strong; they all belong to the form costata

Pfeffer (see above), which occurs abundantly in the Red Sea and the Indian (Jcean. It is only
a variety of the type (Boas) ^).

Subgenus Cavolinia (s. str.J Pelseneer.

Hyalaea (part.) Auctorum.

Plettropus (part.) Auctorum.
1850. Diacria (part.) Gray, Catalogue of the Mollusca in the Collection of the British

Museum, prt. II, Pteropoda, p. 10.
1886. Hyalaea, B Boas, Spolia atlantica, Bidrag til Pteropodernes Morfologi, etc, p. 92.
1888. Cazwlinia (s. str.) Pelseneer, Challenger Rep. LX VI, p. 20.

3. Cavolinia tridentata (Forskal).

1767. t Monociilus teleuius Linné, Systema Naturae, 12*'' Ed., vol. i, prt. II, p. 1059.

1773. Anotnia tridentata Forskal, Descriptiones animalium quae in itinere orientali obser-

vavit, p. 124.
1783. Giocnia sp. ? Gioëni (fide Souleyet), Descrizione di una nuova Famiglia e di un nuovo

Genere di Testacei trovati nel littorali di Catania.

3

spec.

I

spec.

I

spec.

12

spec.

3

spec.

8

spec.

4

spec.

5

spec.

3

spec.

I

spec.

4

spec.

3

spec.

8

spec.

I

spec.

10

spec.

I

spec.

0

spec.

I

spec.

8

spec.

I

spec.

I

spec.

'

spec.

1

spec.

I

spec.

3

spec.

I

spec.

4

spec.

i) Spolia atlantica, p. loo.

ijgi. Cavolina natans Abildgaard, Nyere Efterretning om det Skaldyr som Forskal har

beskrevet under Navnet Aiwniia tridcntata, Skriv. Naturh. Selsk, Bd. I, Heft 2,

p. 175, pi. X.
iSoi. Hyalaea cornea Lamarck, Système des anim. sans vert. p. 140.
1802. Hyalaea tridcntata Bosc, Hist. nat. des coq., vol. II, pi. X, fig. 4.
1804. Hyalaea papilionacea Bor\' de Saint- Vincent, Voyage dans les quatres principales iles

des mers d'Afrique, vol. I, p. 137, pi. V, fig. i.
18 10. Hyale téniobranche Péron et Lesueur, Histoire de la familie des Mollusques Ptéropodes,

Ann. Mus. Hist. Nat. Paris, vol. XV, pi. II, fig. 13.
18 13. Hyalaea peronii Lesueur, Mémoire sur quelques animaux Mollusques, etc, Nouv. Bullet.

Soc. Philom., vol. III, p. 284.
1813. Hyalaea chemnitziana Lesueur, Ibid, p. 284.

1816. Hyalaea australis Péron, Voyage de découvertes aux terres australes, vol. I, pi. XXXI, fig. 5.
1821. Hyalaea forskalii Lesueur in: DE Blainville, Dict. d. Sci. Nat., vol. XXII, p. 79.
1821. Hyalaea teniobranchia de Blainville, Ibid., p. 80.
1836. Hyalaea affinis d'Orbigny, Voyage dans l'Amérique meridionale, vol. V, p. 91, pi. V,

figs. 6 — 10.
1848. Hyalaea truncata Krauss, Südafrikanische Mollusken, p. 34, pi. II, fig. 12.
1859. Cavolina telcmus A. Adams, On the Synonyms and Habitats of Caz'olinia, Diacria and

Plenropiis, Ann. and Mag. Nat. Hist., ser. III, vol. 3, p. 44.
1877. Caiwlinia ciimingii Sowerby in: Reeve, Conchologica iconica, vol. XX, Pteropoda,

pi. I, fig. 5.
1882. Cavolina tridentata Verrill, Catalogue of marine Mollusca added to the Fauna of New

England during the past ten years, Transact. Conn. Acad. vol. V, prt. 2, p. 554, figs. 6 — 7.
1882. Cavoltma tridcntata Fischer, Manuel de Conchyliologie, p. 434.

Living animals;

Stat. iio. 4° 34' N., 122° o' E. I spec.

Stat. 276. 6° 47'. 5 S., i28°4o'.5E. i spec.

Empty shells:

Stat. 45. 7° 24' S., 118° 15'. 2 E. I spec.

Stat. 52. 9° 3'.4 S., 119° 56'. 7 E. 7 spec.

Stat. 88. o°34'.6N., 119° 8'.5 E. 3 spec.

Stat. 95. 5°43'.5 N., 119° 40' E. 3 spec.

Stat. 100. 6° 11' N., i20°37'.5E. 2 spec.

Stat. 116. o°58'.5N., i22°42'.5 E. i spec.

Stat. 178. 2° 40' S., i28°37'.5E. 3 spec.

Stat. 208. 5° 39' S., 122° 12' E. I spec.

Stat. 211. 5° 40'. 7 S., I20°45'.5E. 5 spec.

Stat. 221. 6° 24' S., 124° 39' E. 4 spec.

Stat. 240. Banda. i spec.

Cavolinia tridcntata occurs in the East-Indian Archipelago, but it is not so abundant as
nearly all the other species of Cavolinia (s. str.J.

BoAS ') distinguished already two variaties which, huwever, are linked to the type by
gradual transitions. One of these varieties, the Hyalaea affinis of d'Orbigny was found at
station 116. It is an e.\treme form and, at first sight, it may be regarded as a Cavolmia
uncinata, with which Cavolinia tridentata is closely allied, but it is distinguished from this species
by the less pronounced dorsal ribs, by the oblique direction of the dorsal lip, the slight

i) Spolia atlantica, p. 116 — 117. See his table 6, fig. 100.

39

divergence of the latcral niargins, and the direction of the t(>rminal point, which does not exhibit
the strong- curvature of Cavolinia nnciiiata at all, but is almost straight (PI. II, figs. 32 — 33).
The variety affinis in its most extreme forms, had been recorded already from the East-
Pacific Ocean (Boas, Spolia atlantica, p. 116).

The variety h'uncata of this author (South-Atlantic and western part of Indian Oceanj
was not found among the Siboga-specimens.

4. Cavolinia itncinafa (Rang).

1836. Hyalaea iincinata Rang, in: d'Orbignv, Voyage dans rAmérique meridionale, vol. V,

p. 93, pi. V, figs. II — 15.
1S50. CavoUna uncinata Gray, Catalogue of the Alollusca in the Collection of the British

Museum, pit. II, Pteropoda, p. 7.
1880. Hyalaea iincinatifonnis Pfeffer, Die Pteropoden des Hamburger Museums, Abh. aus d.

Geb. d. Naturw. herausg. vom Naturw. Ver. Hamburg, Bd. VII, p. 83.
1888. Cavolinia uncinata Pelseneer, Chall. Rep. LXV, p. 84.

Living animals:

Stat. Wj^. i°i5' N., 123° 37' E. 3 spec.
Stat. 303. Haingsisi, Samau Island. i spec.

Empty shells :

Stat.

Stat.

Stat.

Stat.

Stat.

Stat.

Stat.

Stat. 102

Stat. 105

Stat. 117". i°i5

Stat. 136. Ternate.

Stat. 137. o°23'.8 N.,

45-

52.

59-

65».

88.

90.

95-

/

9° 3
10° 22

7° o
o°34
i°i7

5°43
6° 4
6° 8

24' S.,

■•4 S.,

7 S.,

S.,

.6N.,

'.5 N.,

5N.,

iN.,

N.,

N.,

Ii8°i5'.2 E,
ii9°S6'.7E
I23°i6'.5 E
120° 34'. 5 E
119° S'.sE

ii8°53' E
1 1 9° 40'
1 20° 44'
121° 19'

12;

E.
E.
E.
E.

Stat. 139.

Stat. 151.

Stat. 159.

Stat. 178.

Stat. 208.

Stat. 212.

Stat. 221.

Stat. 267.

0° 1 1' S.,

0°I2'.6 S.,

o°59'.i S.,

2° 40' S.,

5° 39' S.,

5° 54.5 s.,

6° 24' S.,

5° 54' S.,

Stat. 300. 10° 48'. 6 S.,
Stat. 312. 8° 19' S.,

127° 29' E.
i27°25' E.
129° 48' E.
i29°48'.8E.
i28°37'.5E.
122° 12' E.
120° 19'. 2 E.
124° 39' E.
[32°56'.7E.
123° 23'.! E.
117=41' E.

1 spec.
10 spec.

2 spec.
2 spec.

31 spec.
I spec.

15 spec.
14 spec.

I spec.

I spec.

1 spec.

7 spec.

2 spec.
4 spec.

17 spec.

32 spec.
9 spec.

8 spec.
2 spec.

1 spec.

2 spec.
I spec.

Cavolinia uncinata^ chiefly represented by empty shells, is a very common form.

Some specimens are remarkably hyaline, but in the sculpture of the shell, the curvature
of the posterior point, as well as in the direction and size of the lateral spines, all the
specimens are very much alike.

40

5- Cavolinia gibbosa (Rang).

1836. Hyalaea gibbosa Rang in: d"Orbignv, Voyage dans rAmérique meridionale, vol. V,

p. 95, pi. V, figs. 16 — 20.
1836. Hyalaea flava d'Orbigny, Ibid., p. 97, pi. V, figs. 21 — 25.
1850. Cavolina gibbosa Gray, Catalogue of the MoUusca in the Collection of the British

Museum, prt. II, Pteropoda, p. 8.
1850. Cavoli)ia fava Gray, Ibid., p. 8.
1880. Hyalaea gegenbauri Pfeffer, Die Pteropoden des Hamburger Museums, Abh. Naturw.

Ver. Hamb. Bd. VII, p. 86, figs. 7— J^r.
1886. Cavolinia gibbosa Locard, Prodrome conchyliologie frangaise, p. 22.

Empty shells:

Stat.

45-

7° 24' S.,

ti8°i5'

.2 E.

1

spec.

Stat.

52.

9° 3'4S.,

19° 56'

.7 E.

I I

spec.

Stat.

59-

IO°22'.7 S.,

23° 1 6'

.5 E.

^
i

spec.

Stat.

65 ^

7° 0' S.,

20° 34'

5 E.

I

spec.

Stat.

88.

0° 34'-6 N.,

19° 8'

5 E.

16

spec.

Stat.

95-

5°43'-5 N.,

1 19° 40'

E.

7

spec.

Stat.

98.

6° 9' N.,

20°2l'

E.

I

spec.

Stat.

100.

6° 11' N.,

20° 37'

5 E.

2

spec.

Stat.

102.

6° 4.1 N.,

20° 44'

E.

6

spec.

Stat.

178.

2° 40' S.,

28° 37'

5 E.

I

spec.

Stat.

208.

5° 39' S.,

22° 12'

E.

6

spec.

Stat.

210'.

5° 26' S.,

21° 18'

E.

I

spec.

Stat.

21 1.

S°4o'.7 S.,

20° 45'

5 E.

4

spec.

Stat.

212.

5° 54'-5 S., 1

20° 19'

2 E.

4

spec.

Stat.

221.

6° 24' S.,

24° 39'

E.

0

spec.

Stat.

300.

io°4S'.6 S., I

23° 23'

I E.

I

spec.

Only empty shells of this species have been found. I think that living animals rarely occur
in the tropics (see d'Orbigny ^), Boas '), Pelseneer ^), Munthe ^j, at least in the neighbourhood
of the equator.

Several authors, among them .Souleyet ") and Benson "), have deplorably confused the
forms Hyalaea gibbosa Rang (= Hyalaea flava d'Orbigny) and Hyalaea gibbosa d'Orbigny
(= Hyalaea gegenbauri Pfeffer). Pfeffer "') has given an account of the different interpretations.

The .Siboga-specimens agree in many points with the form jïai<a d'Orbigny. Very probably,
however, gradual transitions may be found to gibbosa d'Orbigny, and I can scarcely attach an)-
importance to the maintaining of the differences between these forms.

Boas ") described a variety from the Indian Ocean ; I have seen specimens from this
region (32°S., 3i°E.) from the Leyden Museum, which agree with his figure, but the variety
was not found in the collection of the Siboga.

i) Voyage d. rAmér. mér. vol. V, p. 96.

2) Spolia atl. p. III.

3) Chall. Rêp. LXV, p. 82—83.

3) Ptevop. i Ups. Uq. Zool. Mus., Bih. t. K. Sveiiska vet-akad. Handl., Bd. 13, afd. IV, n" 2, p. 25.

5) Voyage de la Bonite, vol. IT, p. 145.

6) Ann. and. Mag. Nat. Hist., ser. III, 7, p. 23 — 24.

7) Abh. Naturw. Ver. Hamb., p. 87.

8) L. s. c, pi. 6, fig. 99(7.

41

From this collection I nuMUiim a single shell (Stat. 102) which exhibits some variations
(PI. II, iigs. 34 — 33). It is inurh imire flattened thaii any otlicr specimen; the transverse grooves
on tlic ventral side are Icss distinct, and the terminal puint is ahnost straight.

6. Cavolinia o-/ol>itlosa (Rang).

1850. Cavolina globidosa Rang, in: Grav, Catalogue of the Molhisca in the collection of the

British Museum, prt. II, Pteropoda, p. 8.
1850. Cavolina pisum IMprch, Catalogus conchyliorum quae reliquit KjERULF, p. 32, pi. I, hg. 7.
1852. Hyalaea globulosa Rang, in: SoULEVET, Voyage de la Bonite, vol. II, p. 142, pi. IV,

figs. 20 — 24.
1888. Cavolinia globulosa Pelseneer, Chall. Rep., LXV, p. 81.

Living animals :

Stat. 96. Pearl-bank, Sulu Archipelago. i spec.

Stat. 143. 1° 4'. 5 S., I27°52'.6E. i spec.

Stat. 144. Damar Island. i spec.

Stat. 177'. 2° 30' S., 129° 28' E. I spec.

Empty shells:

Stat.

52.

9° 3'-4S.,

ii9°56'.7 E.

4 spec.

Stat.

59-

IO°22'.7 S.,

I23°i6'.5 E.

I spec.

Stat.

65^

7° 0' S.,

120° 34.5 E.

I spec.

Stat.

88.

o°34'.6N.,

119° 8'.5 E.

12 spec.

Stat.

95-

5°43oN.,

II 9° 40' E.

I spec.

Stat.

102.

6° 4'-iN..

120° 44' E.

7 spec.

Stat.

137-

o°23.8N.,

127° 29' E.

I spec.

Stat.

139-

o°ii' S.,

i27°25' E.

3 spec.

Stat.

141.

1° o'.4 S.,

i27°25'.3E.

I spec.

Stat.

151.

o°i2'.6 S.,

129° 48' E.

2 spec.

Stat.

178.

2° 40' S.,

128° 37'. 5 E.

10 spec,

Stat.

221.

6° 24' S.,

124° 39' E.

5 spec.

Stat.

267.

5° 54' S.,

i32°56'.7E.

I spec.

This species too has been recorded from many stations. The brown colour on the front
part of the ventral side has quite disappeared in some specimens, which in other respects do
not exhibit any difference with the other shells. From the literature on this species it may be
inferred, that this species does not occur in the Atlantic. After Bo.\s and Pelseneer, it has
been stated by Peck ^) and Smitii "). Pfeffer ^), Munthe ^) and Locard ^), however, have noted
definite localities. It seems extremely rare in this ocean.

'O o'

' o

7. Cavolinia longirosfris (Lesueur).

1821. Hyalaea longirosfris Lesueur, in: DE Blaixville, Dict. d. Sc. nat., vol. XXII, p. 81.
182 1. Hyalaea ecaudata Lesueur, Ibid., p. 82.

1) Proc. U. S. Nat. Mus., vol. XVI, p. 452.

2) Proc. Zool. Soc. 1890, p. 254.

3) .\bh. Naturw. Ver. Hamb., p. 84.

4) Pterop. i Ups. Cn. Zool. Mus., Bih. till I-C. Sv. Vet-akad. Handl., Bd.

5) Exped. Sc. Travailleur et Talisman, Mollusques testacés, t. I, p. 10.
SIBOGA-EXPEDITIE Lil.

13, afd. IV, n" 2, p. 25.

42

1836. Hyalaca liinbata d'Orbigny, Voyage dans l'Amérique meridionale, vol. V, p. loi, pi. YI,

figs. II — 15.
1836. Hyalaea longirostra d'Orbigny, Ibid., p. lOO, pi. VI, figs. 6 — 10.
1850. Cavoüna longirostra Gray, Catalogue of the Mollusca in the collection of the British

Museum, prt. II, Pteropoda, p. 8.
1852. Hyalaea angulata Souleyet, Voyage de la Bonite, Zoölogie, vol. II, p. 152, pi. V. figs. i — 6.
1852. Hyalaea fcinorata Gould, The Mollusca and Shells of the U. S. Exploring Expedition

under the command of VViLKES, pi. LI, fig. 603.
1861. Hyalaea fissilabris Benson, Notes on the Pteropodous Genus Hyalaea, etc, Ann. and

Mag. Nat. Hist., ser. 3, vol. VII, p. 26.
1877. Cavolina longirostris Angas, Marine Mollusca of Port Jackson, Proc. Zool. Soc. London,

p. 178.
1877. Cavolina liiiihata Angas, Ibid., p. 178.

1877. Hyalaea obtiisa Sowerby, in: Reeve, Conch. Icon., vol. XX, Pteropoda, pi. II, fig. 8.
1888. Cavolinia longirostris Pelseneer, Chall. Rep. LXV, p. 79.

Living animals:

Stat. 35. 8° o'.3 S., 116° 59' E.

Stat. 36. 7° 38' S., 117° 31' E.

Stat. 37. Sailus ketjil. Paternoster Islands.

Stat. 66. Between Bahuluvvang and Tambolungan.

Stat. 89. Pulu Kaniungan ketjil.

Stat. 96. Pearl-bank, Sulu Archipelago.

Stat. 99. 6° 7'.5N., 120^26' E.

Stat. 106. Kapul Island, Sulu Archipelago.

Stat. 109. Pulu Tongkil, Sulu Archipelago.

Stat. ii7\ i°i5' N., 123° 37' E.

Stat. 118. i°38' N., I24°28'.2E.

Stat. 121. Menado.

Stat. 136. Ternate.

Stat. 138. East coast of Kajoa Island.

Stat. 141. 1° o'.4 S., I27°25'.3E.

Stat. 143. 1° 4'.5 S., i27°52'.6E.

Stat. 144. Damar Island.

Stat. 148. o°i7'.6S., I29°I4.'5E.

Stat. 165. Daram Island.

Stat. 169. Atjatuning, West coast of New-Guinea.

Stat. 172. Gisser Island.

Stat. I77^ 2° 30' S., 129° 28' E.

Stat. 184. South coast of Manipa Island.

Stat. 185. 3° 20' S., I27°22'.9E.

Stat. 194-197- i°53'-5 S., i26°39'E.— i°4s'.3S., i:

Stat. 205. Lohio Bay, Buton Strait.

Stat. 220. Pasir Pandjang, West coast of Binongka.

Stat. 225. Near the Lucipara Islands.

Stat. 276. 6°47'.5 S., 128° 40'. 5 E.

Empty shells:

Stat. 47. Bay of Bima.

Stat. 51. Molo Strait.

Stat. 59. io°22'.7 S., i23°i6'.5E.

Stat. 88. o°34'.6N., 119° 8'. 5 E.

Stat. 8g. Pulu Kaniungan ketjil.

Stat. 90. i°i7'.5N., 118° 53' E.

3

spec.

8

spec.

10

spec.

5

spec.

I

spec.

zh

20

spec.

±

20

spec.

6

spec.

3

spec.

5

spec.

2

spec.

I

spec.

3

spec.

4

spec.

I

spec.

3

spec.

H

spec.

±

40

spec.

10

spec.

I

spec.

2

spec.

8

spec.

I

spec.

9

spec.

8'.3E

• 5

spec.

4

spec.

I

spec.

I

spec.

2

spec.

1

spec.

I

spec.

I

spec.

3

spec.

I

spec.

10

spec.

43

Stat. 95- 5°43'.5N., 119° 40' E. 22 spec.

Stat. 102. 6° 4'.iN., i20°44' E. 17 spec.

Stat. 105. 6° 8' N., 121° 19' E. 6 spec.

Stat. 137. o°23'.8N., 127° 29' E. 3 spec.

Stat. 139. o°ir S., I27°25' E. 2 spec.

Stat. 151. o'^i2'.6S., 129° 48' E. 5 spec.

Stat. 178. 2°40' S., 128° 37'. 5 E. 4 spec.

Stat. 211. 5°4o'.7 S., i20°45'.5 E. i spec.

The species is very abuntlantl\- distributed over the whole region.

No other species exhibits so maiiy variations. X'ery striking is the difference in size
among the specimens themselves. The lateral points of the small-sized intlividuals are generally less
developed, the dorsal lip is not prolonged into a rostrum, and the shell is hyaline. In the larger
specimens, however, the lateral points are more conspicuous, while the rostrum is long, and
the shell coloured whitish. These characters are not absolutely connected with the size, and the
opinion, according to which the small specimens represent young stages, is erroneous, as Bo.\s ')
pointed out. They are adult individuals, like the large ones, which will not grow further.

Hyalaea angulata -Souleyet was found at nearly every station from which Cavolinia
longirostris has been recorded. But the transitions to this form are so numerous too, that it
is impossible to regard the species of Soulfa'ET as a distinct one.

BoAS ') described a variety, in which the lateral points are more or less curved upwards.
Some specimens of the collection, gathered by the Siboga, agree with his description (Stat. 102),
but here too, grradual transitions make it almost impossible to maintain the clistinctness of
this variety.

I may remark further that a small brown spot sometimes occurs on the dorsal side of
the shell, just above the closing apparatus, while the strong dorsal median rib also exhibits a
brownish colour of more or less extension. These characters, not in any way connected with
any other constant peculiarity of the shell, do not allow me to make a new variety.

8. Cavolinia inflcxa (Lesueur).

1S13. Hyalaea inflcxa Lesueur, Mémoire sur quelques aniniaux Alollusques, etc, Nouv. Bullet.

Soc. Philorn., vol. III, p. 2S5, pi. V, fig. \,A,B,C,D.
1821. Hyalaea elongata Lesueur in: DE Blainville, Dict. d. Sc. Nat., vol. XXII, p. 82.

1835. Hyalaea vaginellina Cantraine, Bullet. Acad. d. Sc, Bruxelles, vol. II, p. 380.

1836. Hyalaea lalnata d"Orbigny, Voyage dans l'Amérique meridionale, vol. V, p. 104,

pi. VI, figs. 21 — 25.
1836. Hyalaea uncinata Höninghaus in: Philippi, Enum. Moll. utriusque Siciliae, vol. I,

p. loi, pi. VI, fig. 18.
1841. Hyalaea vaginella Cantraine, Malac médit., p. 28, pi. I, figs. 6 — 6a.
1850. Cavolina iuflexa Gray, Catalogue of the Mollusca in the collection of the British

Museum, prt. II, Pteropoda, p. 9.
1877. Hyalaea (Diacria) inflexa Sowerby, in: Reeve, Conch. Icon., vol. XX, Pteropoda,

pi. III, figs. \-ja — \]b.
1877. Hyalaea (Diacria) labiata Sowerby, Ibid., figs. \'i>a — 18^.

1) Spolia atlantica, p. 102.

2) L. c. s. 103.

44

i88o. Hyalaea imitans Pfeffer, Die Pteropoden des Hamburger Museums, Abh. Naturw. Ver.

Hamburg, Bd. VII, p. 90, pi. VII, fig. 9^?.
1884. Cleodora inflexa Sowerby, Thes. Conch., vol. V, Pteropoda, pi. I, figs. 21 — 22.
1884. Diacria labiata Sowerby, Ibid., figs. 23 — 24.
1886. CavoUnia inflexa Locard, Prodrome de Conchyliologie frangaise, p. 22.

Living animals:

Stat. 36. 7° 38' S., 117° 31' E. I spec.

Stat. iio. 4° 34' N., 122° o' E. I spec.

Stat. 128. 4° 27' N., 125° 25'./ E. I spec.

Stat. 148. 0° i/'.ó S., 129° 14'. 5 E. I spec.

Empty shells:

Stat. 88. o°34'.6N., 119° 8'.s E. i spec.

Stat. 223. 5° 44'. 7 S., I26°27'.3E. i spec.

This species is not nearly so abundant as the foregoing one.

Hyalaea labiata d'Orbigny, regarded by the author, and many others after him, as a
distinct species, is only a variety of the type. Boas ') described two varieties; one of them,
longa, corresponds with Hyalaea inflexa (in the sense in which Souleyet -) uses the term),
while the other variety is designated under the name of lata (Hyalaea labiata Souleyet "). But
as in so many cases, these varieties are linked together (PI. II, figs. 54 — 63).

The few specimens, brought home by the Siboga Expedition must be referred to the
form lata, which lives in the South-Atlantic, Indian and West-Pacific Ocean (Boas).

Appendix to the Cavoliniidae.

Several zoologists have described new "species" which in reality represent only young
stages of species, already known. Souleyet and Pfeffer have expressed in some cases, though
hesitatingly, their doubt as to the specific distinctness of these small forms, referred to above ;
but it has been Pelseneer *) again who clearly pointed out their sexual immaturity.

But though it is certain, that those forms with their extremely flat shells, without
completely developed closing apparatus, cannot be regarded as distinct species, it is almost
impossible to decide, to what species they must be referred. The characters of the adult forms
are only very vaguely expressed in the young ones, while on the other hand the embryonic shell
of the latter is always wanting in adult specimens of some species. These circumstances prevent
an exact solution of the question, which is not rendered more easy by the fact that several
young stages have been described or figured in a way so incomplete, that I think it will be
impossible to recognize the types, when occasionally found again.

Anatomical investigations (in the case of Cleodora pyg/naea and Plein-opus longifllis)
have shown me, that the gonad does not exhibit lamellar structure, as in the adult, but consists
of numerous rounded follicles, just as in Clio (Creseis). Those of larger size are eggs, while

1) Spolia atlantica, p. 123.

2) Souleyet, Voynge de la Bonite, vol. 11, p. 15Ó, pi. V, figs. 21 — 26.

3) Op. S.C. p. 159, pi. V, figs. 27—32.

4) Chall, Rep. LXV, p. 71.

45

numerous small cells, conglomerating especially around the efferent duet, probably represent
s[)('rmatids. The gonad itself is situated on the mctlian line, at its distal extremity, which is
often curved to the lefl (at least in Plairopiis longifilis). Further information as to the anatomy
of this last forni niay be found in the paper of Gegenbaur ^) ; I only mention the existence of
a gastric coecum, dorsally to the liver and not situated in it, and two insertions of the very
thin columellar muscle at the right side of the base of the terminal point, in which the shell
ends. The dorsai insertion is situated more proximally than the ventral one.

Taking into consideration the questionableness of the true affinities of most of the young
stages, I have thought it better to discuss them separately, and not together with the adult forms.

1. "" Clcodora coinpressa" Souleyet. (PI. II, hg. 64).

1850. Clw dcprcssa Gray, Catalogue of the Mollusca in the collection of the British Museum,

prt. II, Ptcropoda, p. 14, (name only).
1852. Clcodora coinprcssa Souleyet, Voyage de la Bonite, Zool , vol. II, p. 181, pi. VI, fïgs. 26 — 32.

Living animals:

Stat. 203. 3°32'.5S., I24°I5'.5E. i spec.

Stat. 220. Pasir Pandjang, West coast of Binongka. i spec.
Stat. 282. 8°25'.2S., i27°i8'.4E. 2 spec.

The shell as well as the animal shows much resemblance with Cavolinia trispinosa as
Pfeffer ■) already suggested. Very likely it is the young stage of this species. It is useless,
to repeat the proofs of Pfeffer's opinion, as they have already been mentioned by Pelseneer ^).

2. "■ C/eodora pyginaea' Boas.

1886. Clcodora pyguiaea Boas, Spolia atlantica, Bidrag til Pteropodernes Morfologi, etc, p. 84,
pi. 4, t^g. 57, ^Jbis, pi. 5, fig. 90, pi. 4, t^g. 50.

Living animals :

Stat. 36. 7° 38' S., 117° 31' E. 7 spec.

Stat. Tj-j. Sailus ketjil. Paternoster Islands. i spec.

Stat. iio. 4° 34' N., 122° o' E. I spec.

Stat. 136. Ternate. 4 spec.

Stat. 138. East coast of Kajoa Island. i spec.

Stat. 141. 1° o'.4 S., I27°25'.3E. 4 spec.

Stat. 144. Damar Island. 13 spec.

Stat. 165. Daram Island. 2 spec.

Stat. \-jj\ 2° 30' S., 129° 28' E. 9 spec.

Stat. 185. 3° 20' S., I27°22'.9E. I spec.

Stat. 194—197. i°53'.5S., i26°39' E.— 1°45'.3 S., i27°8'.3E. 5 spec.

Stat. 203. 3° 32'. 5 S., 124° 15'. 5 E. 14 spec.

. Stat. 205. Lohio Bay, Buton Strait. 2 spec.

Stat. 245. 4°i6'.5 S., i3o"i5'.8E. i spec.

This form, probably a young stage of Cavolinia quadridentata, "fills up a blank" as

1) Untevs. üb. Ptevop. u. Heterop. 1855, pi. I (Hyalaca coinplaiiataj.

2) Berl. Monatsber. 1879. p. 237.

3) Cha'.l. Rep. LXV, p. 87.

46

Pelseneer ') says, as in the adult form the embryonic shell is always lacking. The dorsal ribs
of '^ Clcodora pygmaca' agree with what is fouiid in the form costata oi Cavoliiiia quadridentata,
occurring abundantly in the East-Indian Archipelago.

3. " Pleiiropris longijilis" Troschel.

1854. Plcuropus longifilis Troschel, Beitrage zur Kenntniss der Pteropoden, Arch. f. Naturgesch.,

Jahrg. XX, p. 208, pi. VIII, figs. 1—3.

1855. Hyalaea coinplanata Gegenbaur, Untersuchungen über Pteropoden iind Heteropoden,

p. 40, pi. I, fig. I.
1886. Hyalaea longifilis Boas, Spolia atlantica, Bidrag til Pteropodernes Morfologi, etc, p. 128,
pi. 4, figs. 64—65, pi. 5, fig. 78.

Living animals:

Stat. 1 36. Ternate. 2 spec.

Stat. 220. Pasir Pandjang, West coast of Binongka. i spec.

This form has been recorded only from the Mediterranean, previous to the Siboga Expedition.

It is certainly the young stage of Cavoliiiia tridentata^ as Pelseneer-) pointed out. Like this
author, I could tracé, out of a certain number of specimens (procured from Naples by Dr. Nierstrasz),
all the transitions between the young and the adult stage (PI. II, figs. 36 — 53). In the seventh
specimen of this series I observed a penis for the first time, and also a gill, while in the foUowing
specimens the gonad, situated more proximally than in the foregoing ones, consisted of lamellae.

4. '^Hyalaea rotundata" Boas. (PI. II, figs. 70 — 71).

1886. Hyalaea rotundata Boas, Spolia atlantica, Bidrag til Pteropodernes Morfologi og Syste-
matik, etc, p. 129, pi. 4, figs. 59 — 61.

Living animals:

Stat. 36. 7° 38' S., 117° 31' E. 2 spec.

Stat. 189". 2°22'S., 126° 46' E. I spec.

The description and figures given by Boas, show clearly that this form presents close
resemblance to Cavoliiiia globulosa, as Boas himself affirms. It certainly corresponds with this
species '*). Living animals, belonging to the adult form, have rarely been met with b)' the
Siboga Expedition ; while the young animals were onl\- represented by a few specimens.

5. '^Hyalaea Icvigatd' d'Orbigny. (PI. II, figs. 72 — 73).

1836. Hyalaea levigata d'Orbigny, Voyage dans l'Amérique meridionale, vol. V, p. iio,

pi. VU, figs. 15 — 19.
1850. Diacria laevigata Gray, Catalogue of the Mollusca in the collection of the British

Museum, prt. II, Pteropoda, p. 11.
1858. PleuropHs laevigatus A. and H. Adams, The Genera of recent Mollusca, vol. II, p. 611.

1) Op. S.C. p. 88.

2) Op. s. c. p. 71, 89.

3) See Pelseneer, Cliall. Rep. LXV, p. Sg — 90.

47

Living animals:

Stat. T,6. 7°38'S., 117° 31' E. ±60 spec.

Stat. ■^j. Saiius ketjil, Paternoster Islands. ± 200 spec.

Stat. 50. Bay of Badjo, West coast of Flores. 2 spec.

Stat. 169. Atjatuning, West coast of New-Guinea. 2 spec.

This form was referred to Cavolinia longirostris by Pelseneer "). His assertion seems,
indeed, very admissible. The strong median dorsal rib in the adult, is already distinct in the
young form.

Cavolinia lo7igirostris is certainly tlie most common species of Cavolinia in the East-
Indian Archipelago. For that reason "■ Hyalaca levigafa" has been caught in very great numbers.

6. Hyalaca depressa d'Orbigny.

1825. "■: Plturopns pcllucidiis Eschscholtz, Bericiit über die zoologische Ausbeute wahrend der
Reise von Cronstadt bis St-Peter und Paul, Oken, Isis, p. 735, pi. V, fig. 2.

1S3Ó. Hyalaca depressa d'Orbigny, Voyage dans l'Amérique meridionale, vol. V, p. iio,
pi. VII, figs. 1 1 — 14.

1850. Clio pellucida {part.} Gray, Catalogue of the Alollusca in the collection of the British
Museum, prt. II, Pteropoda, p. 14.

1850. Diacria depressa Gray, Ibid., p. 11.

1852. ? Cleodora pleuropus Rang, Hist. nat. d. AIoll. Pter., pi. X, fig. 8.

1853. Cleodora cnrvata Huxly, On the Morphology of the Cephalous ;Mollusca, etc, Phil.

Trans. 1853, p. 42, pi. IV, figs. 4—5.
1858. Pleuropus depressus A. and H. Adams, The Genera of Recent Mollusca, vol. II, p. 611.

Living animals:

Stat. 36. 7°38'S., ii7°3i' E. 2 spec.

Stat. 130. 5° o'N., i25°26'.5E. 5 spec.

Stat. 144. Damar Island. 3 spec.

As to the species to which this form must be referred, it is certainly the young stage
of Cavolinia injïexa. The genera! form of the shell and the curvature of the posterior portion
support this opinion. One of the Siboga-specimens (Stat. 144) presents very close resemblance
to the adult form, especially as regards the anterior part of the shell, in which the lips exhibit
the same characteristic size as occurs in the form labiata of Cavolinia injïexa.

Anatomical Notes.

The anatomy of the genus Cavolinia (including the subgenera Diacria and Cavolinia
(s.str.J) is sufficiently well known to dispense with a fresh description. Indeed, the first knowledge
about the organisation of the "Pteropoda" in general, has been obtained for a great deal in
studying the anatom)- of Cavolinia. It has been the species Cavolinia Iridentata especially
which served most frequently for anatomical and histological researches.

It has been pointed out already by the thorough investigations of Pelseneer'), that the

1) Op. 5. c. p. 90.

2) Chall. Rep. LXVI, p. 28—37.

48

genus Cavolinia is placed at the end of a series of forms, provided with external calcareous
symmetrical shell, and is the most specialised genus in this direction.

It seems quite superfluous to repeat all that has been already stated by the different authors,
especially van Beneden ^), Souleyet "), Gegenbaur ■'), Boas ^), and Pelseneer ^), who studied the
anatomy of the genus in question. I shall only restrict myself to a few remarks, partly not
agreeing with Pelseneer's publications, partly completing them.

There are several differences between the two subgenera Dia er ia and Cavolinia (s. s/r.J.
Remarkable in Diacj'ia is the separation of the liver into two lobes, having each its own duet.
This arrangement does not occur in any other group of the Thecosomata. The flexure of the
intestine is ventral in all Cavoliniac-^ it seems unnecessary to state this again, had not Vogt
and YuNG ") been mistaken in this respect.

It must have been a slip of the pen, which made Pelseneer pretend that the heart in
Cavolinia is on the ris^ht side. It is situated on the left.

The genital gland in Diacria occupies the whole posterior portion of the visceral mass,
and is disposed transversely. In Cavolinia (s. str.J, ho wever it is asymmetrical, situated almost
quite on the left side, embracing the strong retractor muscle, while the lamellae of the gland
exhibit the usual direction as in all Cavoliniidae. Transverse sections through this organ show,
that the spermatozoids arise from inner folds of the membrane which envelops the gland. I
could not notice any regularity as to the disposition of the ova in the gland, as several ova
in different stages of ripening were found in the centre as well as at the periphery. According
to Gegenbaur (see above), the ova are produced in the outer parts of the lamellae, while
Knower ") States that "the youngest ova are found in the centre, immediately around the intra-
glandular portion of the duet, the oldest ova with considerable yolk at the periphery". I cannot
agree with either of these statements. Perhaps further histological investigations will throw
some light on the distribution of the ova in the genital gland.

The efferent duet in Diacria arises from the dorsal surfaee of the gland, (|uite at the
right side, then runs over to the left, presenting the same eharacteristic elongated swelling as
in Clio and opens into the accessory genital glands. This swelling of the efferent duet was
also found in Cavolinia inflexa, contradictory to Pelseneer's statement, that this species "has
an ovoid vesicula seminalis, with a very short duet".

In the other species of Cavolinia (s. sfr.J the efferent duet, proceeding from the right
concave side of the genital gland, is very thin, until a long vesicula seminalis, eoiled up at
the left side of the stomaeh, opens into it. This ve.sieula seminalis is sometimes provided with
small swellings from distance to distance ^). The accessory genital glands in Cavolinia fs. str.)

1) Exerc. Zool., Mém. Acad. Sci. Brux., vol. XII, 1839.

2) Voyage de la Bonite, vol. II, p. 100 — 136.

3) Unters. über Pterop. u. Het. 1855, p. i — 40.

4) Spolia atl. p. 86 — 91.

5) Op. s. c. p. 17 — 21.

6) Vergl. Anat. Bd. I, fig. 392 (p. 833).

7) Pteropods with two separate sexual openiiigs, Ann. Mag. Nat. Hist. (6), vol. XIII, p. 529. 1S94.
8) Not ouly in Cavolinia loiigirostris^ as Pelskneer says, but also in Cavolinia tiidciilata.

49

are situated either on the Icft sicle of the stomach or ventrally to it; the albuminiparous gland
is situated at the riyht aiUcrior corner of the muciparous gland.

In Diacria there is a p\riform receptaculum seminis, while in Cavolinia (s. str.) the
receptaculum seminis is scarcely visible, situated on the ventral sidc of the muciparous gland '),
and with a very short duet.

Knower has described in Cavolinia longirostris a second sexual opening, leading from
the muciparous gland directly into the mantle-cavity. He says: "on the left side of the uterine
gland, sections in all planes show a second opening from the reproductive system to the
exterior. This is a slit-like aperture on a slight papilla, on the anterior surface of the visceral
sac and to the left. The opening leads directly into a cili ated fold of the uterine gland, the
ciliated cells of which turn out at the lips of the aperture and become continuous with the
epithelium of the external surface of the body".

I have also found this opening in Cavolinia longirostris, after examining series of
transverse sections. In Cavolinia tridentata I could not see it. In the first species the opening
just described was not on the left side of the muciparous gland, but on the dorsal surface.
The cavity of the muciparous gland, developed at the right side, communicates with the mantle-
cavity by an exceedingly small aperture, bordered by lips which exhibit the same histological
structure as the external epithelium of the muciparous gland. This aperture is perhaps a vaginal
opening, as Knower thinks; I must confess that the explanation of this second opening, never
found in any other Thecosomatous "Pteropod", is not clear to me at all. Among the Bulloidea
Lobigcr and Actaeon also have a separate opening for each sex.

The ciliated seminal groove, leading to the penis, has become a closed ciliated tube in
Cavolinia longirostris, as Knower already discovered.

As to the central nervous system, the form and disposition of the different ganglia is
the same as that, found in all Cavoliniidae. I cannot, however, agree with Pelseneer that
the pedal ganglia in all the species of Cavolinia show an anterior jjedal commissure. This
commissure does exist, according to my own investigations, in the subgenus Diacria and in
Cavolinia injlexa, but I could never succeed in finding it, neither after most careful dissection
nor in a series of transverse sections, in the other species of Cavolinia fs. str.). In these species
each pedal ganglion has a very large ganglionic cell on its proximal median side, but a second
pedal commissure does not exist here. The visceral mass is asymmetrical ; the pallial nerves,
issuing from it, are very strong. From the anterior side of each cerebral ganglion (at least
in Cavolinia tridentata, particularly examined on this point) rises only one tentacular nerve
which, ho'wever, divides into several branches (PI. II, figs. 78, 79).

The buccal cranorlia are fused together into a single triangular mass, attached to the cerebral
o-ancrlia bv a commissure. The nerves issuing from the buccal mass are disposed in the same manner
as in Clio. This conformation of the buccal ganglia is characteristic for all the Cavoliniidae.

l) To my opinion, Knower (see above) has mistaken the distal end of the efferent duet in Cavolinia longirostris for a
seminal receptacle.

SIBOGA-EXPEDITIE LU.

50

Family III. Cymbuliidae.

1841. Cyuibulidae Cantraine, Malacologie méditerranéenne et littorale, Mém. Acad. Sci. Brux.,

vol. XIII, p. 33.
1853. Hyalidae (part.) d'Orbigny, in Ramon de la Sagra, Histoire physique, politique et

naturelle de l'ile de Cuba, MoUusques, vol. I, p. 70.
1855. Cymbitliea Gegenbaur, Untersuchungen über Pteropoden und Heteropoden, p. 211.
1855. Cymbuliacea Troschel, Beitrage zur Kenntniss der Pteropoden, Arch. f. Naturgesch.,
Jahrg. XX, p. 210.
Hyalaeidae (part.) Auctorum.
1885. Alata Wagner, Die Wirbellosen des Weissen Meeres, Bd. I, p. 119.
Cymbidiidae Auctorum.

ThoLigh representatives of this family have been knovvn for a long time, the truc
affinities of the Cymbuliidae were only recognised by Pelseneer ^), according to whom the
Cymbuliidae are not to be regarded as specialised Cavoliniidae (an opinion shared bv the few
authors who had an opinion of their own on this point), but "have descended from Limacinoid
ancestors". Aniong the Limacinidae it is the genus Per ac lis with which the Cymbuliidae (and
especially the larvae) show the closest phylogenetic affinity.

As to the systematic relation of the group, the thorough revision of genera and species,
made by Pelseneer "), has thrown some light on the chaos of names, generally applied to forms
which had been described in an insufficiënt manner. Two circumstances have especially contributed
to the incompleteness of our knowledge about the species, belonging to the family. In the first
place the "shell" of the Cymbuliidae is very readily lost, the consequence of which is that
species have been described as naked which in reality possess a "shell", and on the other hand
some descriptions of species have been based on the examination of empty "shells" only, without
animals. But in addition to this, the young forms of the Cymbuliidae differ greatly from the
adult animals, the result of which was that several larvae were regarded as distinct species.

Taking these facts into consideration, it becomes obvious that new genera and species can
only be established when the material at command is very complete, and shells with the animals
i)i sitit can be observed, so that no doubt can arise as to animal and shell beloneine toeether.

The Siboga Expedition has brought home many Cymbuliidae, the greater part of which,
however, are certainly young forms without shells. Little desirous to increase the number of
incompletely known species, I shall abstain from describing such forms as "new" species, about
which I am unable to give a complete diagnosis.

Whereas after the publication of Pelseneer's work the systematic relations of the
Cymbuliidae to each other have undergone some alterations, I shall tr\- to give again a revision
of the various genera and species of the Cymbuliidae.

The oreneric names are the following- :

Argivora Lesueur. Cymbulia Péron et Lesueur. Dcsiiiopterus Chun. Tiedcinannia Delle Chiaje.
Corolla Dall. Cymbziliopsis Pelseneer. Gleba Forskal.

1) Challenger Report, LXVI, p. 31 — 32.

2) Challenger Report. LXV, p. 93 — 96.

51

The; oenus Argivora was basetl b\- Lesueur oii a small mollusc, first described by hini ')
as a naked Cvmbulia ; hc called it Cyinöulia parva, but proposed to erect for this torm the
new genus Argivora. The species has never been figured, and its description is very incomplete.
Perhaps it is a small specimen of Cymbuliopsis, but absolute certainty cannot bc obtained.

Corolla was established by Dall ") on a small specimen (Corolla spectabilis)\ the genus,
though very nearly related to Ticdeiiiannia, differed from it in the pendant body and absence
of a shell. The genus Corolla was declared by Pelseneer ') to be synonymous with Gleba.
But Dall ^) himself afterwards adknowledged the identity of Corolla with Cymbtiliopsis.

Cvmbulia of Péron et Lesueur ^) includes the species on which the whole family has
been based. Cynibiilia peroni from the Mediterranean is very well known and distinguished
from other forms by a whole series of characters. The genus Cyiubiilia has therefore every
riirht to exist.

The genus Cymbuliopsis was proposed by Pelseneer ^) to receive some forms, formerly
described as species of Cymbulia. Although the species of Cymbtiliopsis resemble Gleba more
than Cvmbulia (the name Cymbuliopsis therefore being not very well chosen), yet there are
some characters which justify the existence of Pelseneer's genus.

The form for which the genus Desmoptcrus has been erected "), seemed to exhibit such
marked differences from any other "Pteropod", hitherto known, that the discoverer who regarded
his Dcsmoptertis papilio as a Gymnosomatous "Pteropod", established a new family Desmopteridae
for it. The description and figures, given by Chun, both of the external form of Dcsmoptertis
papilio and of its anatomy, support, however, strongly the belief that this species belongs to
the Cymbuliidae, an opinion, already expressed by Pelseneer *). I have had occasion to prove
the truth of the suggestion of this last author, as a species of Desmopferus was also found
in the Siboga-material (Stat. 169, West coast of New-Guinea).

The only specimen (PI. III, figs. 80 — 81) very much resembles Desmopterns papilio,
but I have seen no pigment spots on the fins nor on the filiform appendages, which are rather
short. In every other respect this specimen is so very much like the animal of Chun that it
is recognised at hrst sight as a Desmopterus.

As to the anatomy, after having made a series of transverse sections of the Siboga-
specimen, I agree with Chun in almost every respect. The radula, however, consists of three
longitudinal series of teeth ; in a transverse row, so there are three teeth ; this fact does not
correspond with the words of Chun") "etwa 20 — 30 Zahnchen sind in jeder Ouerreihe nach-
weisbar", and it procures an argument the more in favour of Pelseneer's opinion. It has
become obvious by the explanations of this last author :

i) In DE Blainville, Manuel de Conchyliologie, p. 655. The few words of de Blainville are the only information we possess
about this species.

2) Description of sixty new forms of MolUiscs., etc. Americ. Journ. Conch. vol. VII, p. 137.

3) Challenger Report. LXV, p. 103.

4) Nautilus III, p. 30—32, 1889.

5) Ann. Mus. d'Hist. Nat. t. XV. p. 69, 1810.

6) L. s. c. p. 100.

7) Chun Bericht über eine nach den canarischen Insein ausgeführte Reise, Sitz. Ber. Berl. Akad., 1889, vol. III, p. 540 — 546.

8) Sur la position systématique de Desmopterus papilio Chun, Zool. Anz., vol. XII, p. 525 — 526.

9) L. c. p. 541-

52

1° that the genus Desmoptemts belongs to the Thecosomata.
2" that it must be referred to the Cymbuliidae.

Besides, I am of opinion that the specimen of Chun and that of the Siboga Expedition
are nothing but young stages of other species. This supposition is based on the following facts :
i" in the twisting of the Hver into a spiral at the posterior end of the visceral mass ; this

twisting proves, that the animal has scarcely surpassed the embryonic stage, in which a

calcareous external shell is present ^).
2" In the position of the anus at the right side ^).

Furthermore may be remarked, in favour of this opinion :
i" that a gonad is properly not present, as the polygonal ova, situated at the dorsal side ot

the stomach, are not joined by an}' connective tissue.
2" that any tracé of a penis is absolutely wanting,
3" that the animal is very small; the greatest width across the fins is 3,5 mm.

The genus Gleba was founded by ForskAl ") on an animal which most zoologists after
him called Ticdcrnannia ^) ; these names being quite synonymous, the first of those must
be retained.

So the three following titles remain :

(i) Cynibulia. (2) Cyiiióuliopsis. (3) Glcba.

It is very difficult to obtain absolute certainty as to the specific distinctness of many
forms, referred to the Cymbuliidae. This is due to the fact, that most species have been described
and figured by its discoverers in a way so vague and incomplete, that it is almost impossible to
recognize the type on which the species has been based. Pelseneer is the only one who has tried ^)
to give short and clear diagnoses of all the forms, then known. Taking into consideration the
literature on this subject and the material at my disposal, I propose the following diagnoses :

1 . CyDibulia : proboscis short, and fixed to the fin ; fins with a ventral lobe, ending in a whip-
like process; on the dorso-lateral margin the fins exhibit an area devoid of muscular fibres ^) ;
muscular bundies are distinctly radiating towards the lateral and ventral margins of the fins,
and in the ventral lobe. — Shell very thick, especially at the dorsal extremity, in which
the cavity extends ; slipper-like ; covered with spines, which are arranged in rows parallel to
the dorso-ventral axis.

2. Cymbtdiopsis : proboscis projecting, free ; fins with a continuous margin, without ventral lobe,
on the surface of the fins three sets of muscles may be distinctly seen ; the visceral nucleus
is rounded at its aboral extremity, where it exhibits a dark pigmented ring or a spot. —
Shell ovoid ; with a large cavity and a broad aperture, about as long as the half-length of
the shell ; it is covered with rounded tubercles.

1) See Krohn, Beitrage z. Entw.-Gesch. der Pterop. u. Heterop. Leipzig 1860.

2) Icones reium naturalium, pi. XLIII, fig. D.

3) Erected by Delle Chiaje, in van Beneden, Exeicices zootomiques, Xouv. Mém. .•Xcad. Bnix., vol. XII, p. 22.

4) L- c. 93, 96.

5) This area has been indicated in the figure of EoAS (Spolia atlantica, pi. 3, lig. 30) as a deep notch in the fin margin, while
in reality there is only a slight sinuosity.

53

3- Gleba: proboscis free, projecting; iins with a continuous margin, without ventral lobe; on
the latero-dorsal margin of the fins are some very complicated indentations ; the three
sets of muscles in the hns are only distinct at the margins, while in the centre only one
of them, running dorso-ventrally, (so the one in which the hundlcs are all parallel to each
other) ma\- be distinguished. — Shell ovoid, flattened, with hardly any cavity; its dorsal
margin is thickened, the ventral one is thin ; sometimes covered with a few tubercles.

We shall now proceed to examinc successively the two families, which have been collected

bv the Siboofa.

ö

Cymbulia Pcron et Lesueur.

iSro. Cyuihulia Péron et Lesueur, Histoire de la familie des Mollusques Ptéropodes, Ann.
Mus. d'Hist. Nat. Paris, vol. XV, p. 66.

For the characters of the genus, see above.

The right explanation of the organisation has been given by Pelseneer ^). The elongation
of the dorso-ventral axis of the shell has led most authors to believe that the pointed extremity
was anterior and the truncated end posterior. An e.xamination of the animal, however, without
its shell, soon shows that this opinion is wrong, and removes at the same time the difficulty
in comprehending Pelsexeer's arguments, when these are heard for the hrst time. The
only real difference between Cavoliniidae and Cymbuliidae is the presence of an internal
cartilaginous shell in the latter. Both these families have descended from Limacinidae; the
Cymbuliidae are more specialised with regard to pelagic life. — The figure of BoAS ") (though
this author clid not recognize the true phylogenetic affinity of the Cymbuliidae) may serve to
make Pelseneer's opinion better understood.

I shall not enlarge upon the various "species" referred to the genus Cvmóitlia^ as they
have already been discussed by Pelseneer. In some cases figures and even description are
entirely wanting, as in Cyiubiilia obtiisa Lesueur '') (not mentioned bj- Pelseneer). Up to this
time it is only one species we know fairly w-ell. But even this form, Cviiiöulia peroni^ has
never been suffïciently figured. I have had occasion to study some specimens from the
Mediterranean. After careful examination ot the shell, I observed that the rows of spines were
not quite similar in the different specimens. The large forms (62 — 43 mm.) one of which is
figured on Pl. III, figs. 82 — 84, showed on the lateral side three parallel rows (fig. 83, a, b, f),
while other specimens (42 — 26 mm.) possessed only one of these rows (fig. 86, a). In addition
to this, the spines at the aperture which are of unequal size in the large specimens, especially
at the right side where they are very strongly developed, are almost uniform in these small
individuals. Are the latter young forms which have not reached a definite size : Or do they
represent perhaps a new species, not hitherto observed ? I can scarcely admit this last opinion,
as the difference, above noted, among the specimens has never been recorded by any author

1) Challenger Report, LXV, p. 96 — 97.

2) Spolia -A.tlantica, p. 25, fig. G.

3) In DE Bl,\inville, Manuel de Conchyliologie, p. 655.

54

who studied the Mediterranean species. The little material as yet at my disposal has not
enabled me to decide upon the question; I, therefore, have restricted myself in figuring the two
types only (PI. III, figs. 82 — 87) and to indicate the difference between them, hoping to pubHsh
hereafter further researches of my own, in order to make out whether we have to do with
two really distinct species or not.

Pelseneer ') described a second new species of which he had seen the shell only. This
shell of Cymbulia parvidentata is distinguished especially by the constriction towards the
middle of its length.

Finally a third species has been caught by the Siboga Expedition.

I. Cymónlia sibogae n. sp. (PI. III, iigs. 88 — 90).

Living animals:

Stat. 165. Daram Island. i spec.

Stat. 189''. 2° 22' S., 126° 46' E. I spec.

Empty shells:

Stat. 148. o°i7'.6S., i29°i4'.5E. 8 spec.

Stat. 165. Daram Island. i spec.

Stat. 167. 2°35'.5 S., 131° 26'. 2 E. 2 spec.

Description: Shell slender, with the dorsal portion very much pointed ; spines on the
surface very small and all of nearly the same size, even those which surround the aperture.
The rows of spines are arranged in nearly the same way as in the small type of Cymbulia
peroni, but the two rows ending in the ventral points do not exhibit the constriction in its
middle (compare figs. 87 and 90), being almost straight throughout their length.

The animal shows very great resemblance with Cymbulia peroni\ I could not observe
any marked difference from this species, except in the smaller size. The proboscis, the tentacles,
the fins, the foot and the pallial gland (the latter was only preserved in the specimen of
Stat. 165) are entirely like the corresponding organs in the Mediterranean species.

Dimensions: 2 4 — i i mm.

R e m a r k s :

I. This species exhibits some characters which are common to both the species of Cymbtilia,
actually known. It seems to have close affinity with Cymbulia pcroni (the small type) but
is distinguished from it:

1° by the acute dorsal extremity.

2" by the straight rows on the aboral surface of the shell ; in Cymbulia peroni these

rows are more sinuous.
3° by the smaller size.
4" b)' a shallower sinus at the ventral end.

I) L. s. c. p. 97, pi. II, figs. 12—13.

55

On the olher hand it diffcrs from Cymbiilia parvidentata:
i" in having no constriction of the shell, nor the sharply marked angle of the two rows

which end in the ventral points.
2" in the possession of two rows (fig. 90, d) reaching the middle of the shell ; these

rows do not run so far in Cyinbulia parvidenfata (the figure of Pelseneer is without

accompan\ing letters).

II. Of the two specimens of this new species, which were attached to the shell, only one has
been very well preserved (in formol 4%). The other is not in a good condition, as the pallial
gland was damaged by the influence of alcohol. I have referred to this species the empty
shells of the Siboga-material, though most of them are in a bad condition. Among these
shells there are some of very small size, scarcely reaching 11 — 12 mm.

Some specimens of Cyuibiilia, with a ventral lobe to the fin, may be briefly described
here. As the shells are wanting, I shall abstain from giving them any specific title.

A. A form (fig. 91) which bears a ventral lobe proportionnally longer than in Cymbiilia
sibogac^ but in every other respect entirely like this species :

Stat. 99. 6° 7'.5 N., 120° 26' E. i spec.
Stat. 245. 4° 16'. 5 S., i30°i5'.SE. 2 spec.

B. A specimen (fig. 92) in which the dorso-lateral margin of the fin does not e.xhibit the
characteristic area without muscular fibres; the width across the wings is only 6 mm.

Stat. 165. Daram Island. i spec.

C. Finally a specimen (fig. 93) with the same habitus as Cyinbulia sibogae^ very probably
identical with it :

Stat. 143. i°4'.5 S., 127° 52'. 6 E. i spec.

Anatomical Rem ark s.

The study ol the little material at my disposal has given me occasion to note something
about the anatomy which does not cjuite agree with former researches. Though my remarks
are not complete, I hope to renew hereafter my researches at the Naples Zoological Station.

The pallial gland is asymmetrical ; the right portion is more developed than the
left, though this latter extends more ventrally. The proximal part of the gland is divided
by a broad transverse asymmetrical band, which consists of two parts (PI. III, fig. 94, d)
The distal portion also exhibits a narrow band (b). M)- description difters a little from that
of Pelseneer ^).

The digestive tract. Two rounded salivary glands are situated just before the
radula ; they ma)- be distinctly seen on transverse sections. The oesophagus is strongly

i) Chall. Rep. LXVI, p. 22, pU III, fig. 8.

56

longitudinally folded and opens widely into the stomach. The posterior part of this latter has a
strong layer of circular muscles. In the stomach are iour large horny plates, two dorsally and
two ventrally. Between the two dorsal plates, a httle more distally, is situated a fifth triangular
plate. The dorsal position of this posterior plate is remarkable, for in the Cavoliniidae it is
situated on the ventral side. Pelseneer does not say whether this plate of the Cymbuliidae
is dorsal or ventral.

The liver extends very far forward; it opens into the stomach, immediately behind the
horny plates, by a very large opening, situated a little to the right of the median line. This
wide hepatic duet soon divides into two. According to Gegenbaur ^) there are from three to
six canals. Souleyet ") mentions: "un conduit assez large qui s'ouvre a l'origine de l'intestin".
Finally Pelseneer has seen two hepatic ducts. After receiving the hepatic duet the stomach
exhibits dorsally a large and short coecum, in which the brown villi of the stomach extend.
A long intestine is coiled up in the liver and in the gonad; its walls are extremely thin,
consisting only of one layer of flat ciliated cells. The intestine is curved in the same way as
in the Cavoliniidae; the anus, however, is quite ventral, scarcely reaching the median line,
whereas, as one knows, in the Cavoliniidae the anus is situated at the left side.

The generative organs. The gonad is especially developed on the left side, but
distally it occupies the whole posterior portion of the visceral mass. It is composed of lamellae
as in the Cavoliniidae; the histological structure too is nearly the same, but I found the ova
in the central portion; peripherically the spermatozoids cling together. At the anterior part of
the gland, at its concave side, a narrow duet proceeds from it (PI. III, fig. 95, a). This duet,
with occasional dilatations, surrounds the accessory genital glands, which are situated before
the stomach, on the ventral side. The large muciparous gland {ó) is strongly folded, especially
on the ventral surface ; a small albuminiparous gland (c) may be distinguished at the right
side. The latter shows a peculiar external structure of bunch-like elevations. Between the two
glands a receptaculum seminis with a rather long duet {d) is situated, and here too a vas
deferens (e), soon becoming a spermatic groove, arises.

The penis opens in the middle line, behind the tentacles. The walls of the copulatory
organ are very strongly folded, and there is an epithelium of high cells with deeply staining nuclei,
which is so characteristic of the Cavoliniidae, but no horny stylet in the cavity of the penis.

The central nervous system. A short description may be sufficiënt, as the
nervous system has already been recognised in its peculiarities by Pelseneer ■').

The cerebral ganglia, situated at the side of the oesophagus as in all Thecosomata, and
united by a long .supra-oesophageal commissure, are rather elongated (PI. III, figs. 97 — 98, c).
The pedal ganglia (/) are the largest, coloured whitish, and nearly circular. The second pedal
commissure (figs. 96, 98, a) has not been figured nor menticjned in this genus by any previous
author. In the arrangement of the visceral ganglia (v.J^.z'.) is shown again the phylogenetic
affinity to Peraclis. These ganglia are three in number and disposed symmetrically ; the two outer

1) Untersuchungen über Pteropoden und Heteropoden, p. 48.

2) Voyage de la Bonite, vol. II, p. 234.

3) L. s. c, p. 24 — 26, pi. III, figs. 10 — II.

57

ones are of the same size, somewhat smaller than the median {p. t'.). The lateral visceral
ganglia (fig. 97, z') are not in any way connected with the pcdal ganglia, but with the cerebral
ones. So the central ncrvous system is quite symmetrical. The distribution of the nerves
is the following :

From the anterior part of each cerebral ganglion three nerves proceed (fig. 97 — 98, 6 — 8).
A slight sinuosity, already observed by Pelseneer, divides the ganglion into two segments; from
the dorsal segment the tentacular nerve arises (6); the two other nerves supply the proboscis.

The pedal ganglia give origin to two large nerves (figs. 96 — 97, i), ramifying very
widely into the fins, as may be seen in fig. 99. Two of the branches extend in the ventral lobe
of the fin. Besides, from each pedal ganglion issues a nerve, directed forward (fig. 98,
9 — 10); a similar nerve occurs in Cttvierina. I could not make out which part of the animal
is innervated by these nerves, (perhaps the retractor muscle of the proboscis).

From each lateral visceral ganglion a very strong mantle-nerve proceeds (fig. 96, 2 — 3);
two nerves innervating the visceral mass, issue from the median visceral ganglion. The stronger
of these nerves (5) jsi'oceeds from the posterior part of the ganglion, slightly to the left, another,
very thin, arises from the right side (5). The implantation of (4) and (5) is the only clearly
marked asymmetry in the nervous system.

The buccal ganglia are closely approximated, but yet distinct. These ganglia, as well
as the nerves issuing from them, have already been described and figured by Pelseneer ^).

Cymbuliopsis Pelseneer.

Cyvibnlia (part.) Auctorum.
1872. Corolla Dall, Description of sixty new forms of Molluscs from the West coast of North-

America and the North Pacific Ocean, Americ. Journ. of Conch., vol. VII, p. 137.
1888. Cymbuliopsis Pelseneer, Chall. Rep., LXV, p. 100.

The species of Dall is very imperfectly known, and as no figure exists of Corolla
spedabilis and its diagnosis, given by Dall, consists only in the negative character of the
absence of a shell, it remains doubtful whether the species belongs to Cymbuliopsis, notwith-
standing Dall's assertion (see p. 51). The genus is distinguished from Cyiiibrtlia and Gleba by
the presence of a shell with a very large cavity and thin walls. The animal very closely resembles
Gleba, having a proboscis, free throughout its length, a fin without ventral lobe, and with neither
radula nor jaws. As far as I can judge, however, it difïers from Glcba by the three very
distinct muscular systems in the fin, and in the absence of the indentations on the fin margin.
As only very few species of both these genera are known, it is very probable that other forms,
not yet discovered, will link together the two types.

The discrimination of the species of Cymbuliopsis was no easy task, as the type-specimens
have been very imperfectly described, and scarcely any attempt has been made to compare
the various species mutually ■).

1) L. s. c, p. 26, pi. IV, fig. 2.

2) A laudable exception is made by Pelseneer (Chall. Rep., LXV, p. loo — loi).

SIBOGA-EXPEDITIE Lil.

58

Three species have been described in literature. Tliey are the following :

1. "■ Cy?nóulia' ovata Quoy and Gaimard.

2. "■ Cymdulia" calceola Verrill.

3. Cymbuliopsis vitrca Heath and Spaulding.

"^ Cytnbulia' ovaia is very imperfectly known ; I shall discuss this species further on.

The summary description ^) given by Verrill, of "" Cymbulia' calceola and especially the
smallness of the rather schematical figure ") does not allow absohite certainty as to the specific
distinctness of the species, about which, however, we possess a rather extensive anatomical and
histological study by Peck ^). It is possible that the "" Ticdeniannia' mentioned by Boas *) may
be identical with "■ Cyiiiónlia' calceola. At any rate tlie specimen of Boas is a Cyuibjiliopsis as
is elucidated by the shortness of the proboscis and the three distinct muscular sets in the fin.

Cymbuliopsis vitrca '") is somewhat better known ; it seems to resemble very closely the
preceding species. Perhaps it is the same as Corolla speetabilis^ and consequently also identical
with the form obtained by the Challenger Expedition "), these forms occurring in the same
locahty (North Pacific Ocean).

None of the specimens of Cymbuliopsis in the Siboga-material can be identified with any
of the foregoing species. At least one new species may be established. Taking into account
the incompleteness of the description and the figures, given by Ouoy and Gaimard, it remains
doubtful whether the specimens from the British Museum, described by Pelseneer ''), belong
really to Cymbuliopsis ovata. The same is true of Cymbuliopsis calceola., the anatomy of which
was studied by Peck (see above). The diagnosis of this species, procured by its discoverer, is
insufficiënt. I have tried to give a synopsis of the species of Cymbuliopsis, actually known.

Synopsis of the species.

1 . Shell somewhat pointed at its ventral margin ; aperture shorter

than half the length of the shell . Cymbiiliopsis ovata.

Shell rounded at the two extremities, aperture longer than half
the length of the shell 2.

2. Fins projecting beyond the ventral margin of the shell almost

half its width Cymbuliopsis vitrea.

Ventral margin of the shell extending nearly as far as the
anterior border of the fins 3.

3. Tubercles regularly placed all over the shell Cymótiliopsis calceola.

Tubercles irregularly placed, smaller and closely grouped together

on the aboral surface of the shell ; entirely absent at the ventral margin Cymóuliopsis intermedia.

1) In: Amedc. Journ. Sci. and Aits, voL XX, p. 392 — 394, iSSo.

2) In: Tvansact. Connect. Acad., voL V, pi. LVIII, fig. 33.

3) Stud. Biol. Lab. J. Hopkins Univ., vol. IV, p. 335 — 553.

4) Spolia atlantica, p. 141, p. 3, fig. 31.

5) Heath & Spaulding, Proc. Ac. Nat. Sci. Philadelphia, vol. LUI (igoi), p. 509 — 511).

6) Pelseneer, Chall. Rep., LXV, p. 104.

7) L. s. c. p. 100, pi. II, figs. 15 — 16.

59
Two species have been observed in the East-Iiulian Archi|jelao;o as yet.

*i. Cymbuliopsis ovata (Quoy and daimard).

1832. Cytnbulia ovata Quoy and Gaimard, Voyagc de l'Astrolabe, vol. II, p. 373, pi. 27,

figs. 25—30.
1852. Cytnbulia ovitlaris Rang, Histoire naturelle des Mollusques Ptéropodes, pi. XI, figs. i — 6.
1888. Cymbuliopsis ovata Pelseneer, Chall. Rep. LXV, p. 100, pi. II, figs. 15 — 16.

This species, with short aperture and regularly placed tubercles, was found by OuoY and
G.A.IMARD in very large shoals off Amboina. Since then, however, never anj- other locaHty has
been recorded, and at Amboina it was never found again, even not by the Siboga Expedition.

SouLEYET ') thinks that Quoy and Gaimard, figuring the species, were mistaken as to the
relative position of the animal to its shell ; in this respect, however, the figure is exact, though
otherwise it is not very reliable. Those of Pelseneer are decidedly better, but the animal is not
figured, and Pelseneer does not say, whether the specimen which served him for anatomical
study, belonged to this species or not.

2. Cymbuliopsis intermcdia n. sp. (PI. IV, figs. 100 — 104).

Living animals:

Stat. 144. Damar Island. i spec.

Empty shells:
Stat. 48. 8° 4'
Stat. 166. 2° 28
Stat. 167. 2° 3 5
Stat. 295. 10° 3 5
Stat. 312. 8° 19

7 S., II 8° 44'. 3 E. I spec.

.5 S., 131° 3'.3 E. I spec.

,5 S., 131° 26'. 2 E. 3 spec.

.6 S., i24°ii'.7E. I spec.

S., ii7°4i' E. I spec.

Description: The shell exhibits the usual characters of Cynibtiliopsis. The aperture
is always somewhat longer than half the length of the shell. In the distribution of the
tubercles I could not observe any regularity; on the aboral surface are some which are smaller,
more closely grouped together; at the ventral margin there are none (figs. 102, 104). This
character of the shell agrees partly with what is found in Cymbtiliopsis vitrea. Aperture
unarmed, thickened lateral sides; these thickenings disappear towards the ventral margin.
Tubercles at the oral surface sometimes fused together into mere unevennesses, separated by
shallow grooves. Animal as in other species of Cymbuliopsis ; proboscis short and broad,
tentacles very short; fins with three distinct systems of muscles; anterior border of the fins
scarcely projecting the ventral margin of the shell (almost as in Cynibitliopsis calceola) ; pallial
gland twisted to the left, with three transparent bands.

Dimensions: 39 — 23 mm. Shell of Stat. 144: 30 mm.

Colour of the shell: Generally transparent, sometimes yellowish, or even dark-
brown (alcohol- and formol-specimens).

l) Hist. nat. d. Moll. Ptéiop. p. 68.

6o

R e m a r k :

I. The description is taken especially from the specimen of Stat. 144, which was still attached
to the shell. The empty shells are so much alike the one of Stat. 144, that, to my opinion,
they equally belong to Cyinbttliopsis intcmnedia.

Several specimens of Cyiubiiliopsis without sliell were found by the Siboga. I shall not give
them any specific title. In the general aspect of the animals I cannot observe any marked difference
from the species above described. The dimensions, however, are sometimes quite different, and
vary from 35 to 6 mm. The formol in which the specimens for the greater part liave been
preserved, has seriously damaged the mantle-organs, the pallial gland, and even the nucleus.

One of the specimens is figured on PI. IV, fig. 105.

They were found at the following localities:

Living animals:

Stat. 124. 2° 27' N., 125° 35' E. I spec.

Stat. 141. 1° o'.4 S., I27°25'.3E. i spec.

Stat. 148. o'^i/'.óS., I29°I4'.5E. i spec.

Stat. 165. Daram Island. i spec.

Stat. 167. 2^35.5 S., i3i°26'.2E. I spec.

Stat. 185. 3° 20' S., I27°22'.9E. 2 spec.

The specimen of Stat. 167 is perhaps a Cyinbnliopsis intcrincdia, as at this same
station three shells of this species have been collected.

Some larval forms of Cymbuliidae have been recorded by the expedition. The general
habitus of these larvae differs very much. Some of the forms are figured on PI. IV, figs.
106 — 108. They bear curious appendages to the fins. Their affinity to any adult form cannot
be made out; ver^' probably they belong to various genera.

The followincf localities were recorded :

Living animals:

Stat. 141. 1° o'.4 S., i27°2s'.3E. 4 spec.

Stat. 143. 1° 4'.5 S., i27°52'.6E. 8 spec. '

Stat. 185. 3° 20' S., i27°22'.9E. 8 spec.

Stat. 203. 3°32'.5S., I24°I5'.5E. ±15 spec.

Stat. 225. Near the Lucipara Islands. 2 spec.

Stat. 276. 6°47'.5 S., i28°4o'.5 E. i spec.

The specimen without shell of the Challenger (Chall. Rep. LXV, p. 99) is a larva, as
it bears appendages to the fins. I have studied this specimen in the British Museum.

Anatomical Remarks.

The close resemblance which Cyiiibuliopsis shows to Gleba, is also markedly expressed
by the visceral anatomy of both genera.

The information we possess regarding the anatomy of Cymbuliopsis is restricted to a

6i

few remarks of Pelseneer '), a stvidy by Peck ") on Cymbuliopsis calceoh, and a [jreliminary
note of Heath and Spaulding ■*) on Cymbuliopsis vitrca. About Glcba we know somethino-
more, especially after the researches of van Beneden *), Gegenbaur '") and Pelseneer ").

As I have had an opportunity to examine some specimens of Glcba, brought home from the
Naples Station by Dr. Nierstrasz, I have been able to compare the results of my examinations
of Gleba with those, obtained from the study of Cymbuliopsis. Some specimens of this latter
genus were investigated by making a series of transverse sections.

As no sufficiënt drawing of Gleba cordata exists, and in order to show the muscular
fibres in the fins, already alluded to, a figure is given on PI. IV, fig. 109. Fig. 110 represents
the shell. \\\ the small specimens, however, the shell bears no tubercles, and is perfectly smooth.
I may further remark, that the number of indentations is not always five, but varies in different
specimens from six to four.

The palhal gland presents a similar aspect in both genera (PI. IV, figs. iii — 112). It
is somewhat asymmetrical, and three transverse bands divide the shield in four parts. The most
proximal of these bands («) is very narrow, the second {b) is the broadest and asymmetrical
while the most distal ie) does not divide the pallial gland over its whole breadth, as this
band does not reach the right side. In Cymbuliopsis as well as in Glcba the pallial gland is
twisted slightly to the left, contradictory to Peck, who described and figured the pallial gland
of Cymbuliopsis calccola, as twisted to the right. Neither radula, nor jaws or salivary glands
are found in each of the genera. The very long oesophagus is more markedly separated from
the stomach as in Cymbulia. In the stomach, situated quite dorsally and slighth' to the right
in the visceral nucleus, are found the same horny masticatory pieces as in Cymbulia.^ the fifth
plate being equally dorsal, as Peck stated already in the species, studied by him. xA coecum
could scarcely be indicated, and was even entirely absent in Cymbuliopsis. A little to the right of
the median line opens the liver with a very large opening. The liver occupies almost the whole
visceral nucleus, extending proximally even as far as the central nervous system, so that its
proximal end is interposed between the ganglia and the oesophagus. Immediately beneath the
hepatic opening a very thin intestine arises which takes its direction to the left side, and then
runs on at the dorsal side of the stomach to the right. Though the extreme portion of the
rectum is directed to the left, the anus does not reach the median line, and opens to the right
of it (PI. IV, fig. 113).

The heart and the kidney are situated above the visceral mass. The kidney (PI. IV,
fig. 114, ö) has a semi-lunar shape, and at its concave side, towards the nucleus, is found the
heart [a). Both these organs are situated nearly in the median line, but the left lobe of the
kidney is slightly more developed than the right. The opening into the mantle-cavity is found
at the right side {d) \ it is represented in the figure in a contracted state. I have not found,

:) Challengei- Report, LXVI, p. 26 — 27.

2) Stud. Biol. Lab. J. Hopk. Univ., vol. IV, p. 335 — 353.

3) Pi-oc. Ac. Nat. Sci. Philadelphia, vol. LUI (1901), p. 509 — 511.

4) Acad. Roy. de Bruxelles, tome XII, p. 21 — 27, pi. II.

5) Gegenbaur. Untersuchungen über Pteropoden und Heteropoden, p. 54 — 68.

6) L. s. c, p. 27 — 28.

however, the reno-pericardial opening, neither in GIcba nor in Cyiiibuliopsis. Gegenbaur and
Peck have equally sought in vain for this opening. The pallial cavity of most of the specimens
of Cyinbuliopsis at my disposal being in a very damaged condition, I have not ventured to
sacrifice the only type-specimen of Cymbuliopsis intenncdia, that I might perhaps discover this
opening. In Glcba I did not succeed in finding it, notwithstanding many attempts.

In this genus, however, I have found an opening {é) in the mantle, at the right side. It is
oval and surrounded by a sphincter; the pallial cavity communicates through it with the exterior.
The presence of this opening seems to me quite unique; I could not discover in literature
any mention made about it. — The heart "hat so ziemlich die Gestalt eines Kartenherzens" as
Gegenbaur already said. On its walls, as on those of the wide aortae, large nuclei are distinctly
visible. Gegenbaur mentions three vessels proceeding from an aorta, I have seen only two of
them («■(?,, aOj)\ and an auricle I did not observe at all. Readily admitting the incompleteness
of my description of the excretory and circulatory organs, I hope, however, to take these
studies up again as soon as possible.

About the generative organs I can scarcely mention anything. For it is a peculiar
fact that any tracé of a gonad, of accessory genital glands and even of a penis, is entirely
wanting in some specimens. The lack of a penis has already been recorded by Peck. The
gonad is distributed over the visceral nucleus as a thin sheet. As to the genital duet and the
accessory glands, I could not observe anything with some certainty. Gegenbaur's description,
and especially his figure of the generative organs in Glcba, seems a priori somewhat strange.

The central nervous system resembles very much that of Cyuibiilia. The number
and disposition of the ganglia is the same (figs. 115 — ^116). The cerebral ganglia (/) are
elongated ; at their anterior side a segmentation presents itself, which is more clearly marked in
Gleba ; at their posterior side a globular swelling is visible in Cymbuliopsis, while in Glcba this
swelling is divided into two or, .strictly speaking, three smaller ones. As Pelseneer already
remarked, nerves do not proceed irom these swellings. The cerebral commissure is extremel}*
long, and distinctly separated from the cerebral ganglia. The arrangement of the pedal (/) and
visceral ganglia (v. p. e'.) is quite similar to that in Cyinbiilia. A small anterior pedal commissure
is equally found here. The posterior visceral ganglion is somewhat larger than the two lateral.
According to the figure of Peck the three visceral ganglia are of the same size. The nerves
arising from the ganglia are disposed in exactly the same manner as in Cxiiibiilia, at least as
regards the pedal and visceral ganglia. — P^rom the anterior side of the cerebral ganglia
only two nerves issue (not three as in Cymbulia). Both these nerves arise from the ventral
segment. The more ventral (i) which is the stronger and somewhat swollen at its base,
supplies the tentacle, a very thin and slender nerve (2) goes to the penis. This latter nerve
does not .seem to have been perceived either by Peck, or by Pelseneer. The first author
mentions two cerebral nerves of which the dorsal supplies the tentacle, while the other
innervates the proboscis. I cannot agree with this explanation, for according to my inve.sti-
gations, the nerve to the proboscis proceeds from the pedal ganglion. Pelseneer has only
made reference to the tentacular nerve in Gleba. — The pedal ganglia give origin to the same
nerves as in Cymbulia: two large nerves (4,5), ramifying widely into the fins (fig. 117), issue

63

from each ganglion. From tlie anterior side a slender nerve (3) innervates the proboscis;
Pelseneer tirst spoke about this nerve in Gleba. — brom the visceral ganglia four nerves arise;
each mantle-nerve (6) soon divides int(i two branches; the lower branch of the right nerve
supplies the osphradium. The two nerves of the posterior visceral ganglion inncrvate the
visceral mass.

The two juxtaposited buccal ganglia, close to the oesophagus, are situated a little
before the pedal ganglia. The arrangement of these ganglia is characteristic of the Cymbuliidae
as well as of the Limacinidae.

GYMNOSOMATA de Blainville.

1824. Gyinnosoviata de Blainville, Dict. d. Sci. Nat., vol. XXXII, p. 271.

1885. Deutocephala Wagner, Die Wirbelloseii des weissen Meeres, Bd. I, p. 119.

1886. Pterota Boas, Spolia atlantica, K. dansk. Vidensk. Selsk. Skriv., 6 Raekke, Bd. IV, p. 14.

The Gymnosomata form a group among the Tectibranchia which exhibits the nearest
affinity with the Aplysioidea. For that reason they are not so closely related to the Theco.somata
(which are Bulloidea modified in adaptation to their pelagic life) as to unite these two groups
to the order "Pteropoda". In spite of many points of resemblance, generally based on
convergence, the whole organisation of the Gymnosomata is quite different from that of the
Thecosomata. Both these groups possess a different origin.

This important fact, already alluded to by Boas ^), has been amply discussed by
Pelseneer ") who, correcting some of Boas' suggestions, was the first to tracé out the phylogenetic
affinity of the Gymnosomata (see also p. 6).

From a systematic point of view the GNinnosomata were very unsatisfactorily known,
not yet twenty years ago. Now, it is true, that the study of these animals, stil! more than that
of the Thecosomata, is made difficult by several facts. First the animals are generally very
small, and their bodies being strongly and irregularly contracted in the preserving fluid, it is
not easy to describe their true shape. In the second place the buccal appendages, on which the
systematization is mainly based (at least as regards the species of the same genus), are nearly
always retracted in preserved specimens, and not visible externall)'. Finally, the gills are often
concealed under the large folds of the body-wall. And so, every point for a right conception,
regarding the systematic position of any member of the Gymnosomata, can only be obtained
by means of careful examination and dissection.

Notwithstanding the acknowledgment of the difficulties above mentioned, one can scarcely
suppress an angry feeling against such authors as Ouoy and Gaimard, Bruguière, and even Rang.
For these naturalists, describing "new species" without indicating any specific distinctness, and,
indeed, destitute of any knowledge about the organisation of these animals, have been the

0--,

i) Spolia atlantica, p. 179.

2) Chall. Rep. LXVI, p. S2— S8.

65

cause tliat these "species" are now very vaguely knovvn, and will rcniain so in ilie üterature on
the Gymnosomata, without mucli possibihty that other naturahsts may recognize them with certainty.

Though the studies ot' Cuvikr, Eschricut, dk Blainville, van Beneden, Souleyet,
Gegenhauk, Tkoschel, MCia.KR, 1m)i., Kroiin and Wagner — treating of whole groups or of
a single sjjecies only — have decidedly their merits, it was not until Boas and Pelseneer took
up their tasks, that the systematic classification of the Gymnosomata became clearly established.
Many of tlie species formerly described, ovight to be oblitcrated as real species, as their
characterization is insufficiënt, only a few should remain. On the other hand, the number ot
distinct species was importantly increased by the two last-mentioned zoologists. The result of their
monographs was, that twenty-one species were then really known. These species belonged to
five families and seven genera (Pelseneer).

It may be supposed, however, that we know onl)' a small number of the species, really
existing in our seas. So, from the INlediterranean some peculiar larvae were formerly described
by Gegenbaur^), which since that time no naturalist has found again, at least not in the adult state,
but which belong to a genus Thiiptodoii, established by Boas "). Many of the species, badly
described by previous authors, may nevertheless represent curious types, about the characters
of which we unfortunately do not possess sufficiënt Information. According to the preliminary
notes of jNIeisenheimer, there has already been found in the material of the Valdivia Expedition
a new family, Pteroceanidae ^), and one new genus Schizobracliiuin ^).

And finally the results of the Siboga Expedition show that explorations in a rather
limited area, as the eastern part of the Indian Archipelago, may procure very sufficiënt results.
For six genera, one of w^hich is new, are represented in the collection, while the number of
species amounts to eight. Plve of them had not been described before.

1840.
1846.
1853-

1855.
1856.
1858.
1862.
1863.
1871.

1887.

Family I. Pneumonodermatidae.

Pneuinodennidac (part.) Gray, Synopsis of the contents of the British Museum, p. 86.

Fneuniodeiniudae Agassiz, Nomenclator zoologicus, Inde.x, p. 299.

Pneuinodcnnidae (part.) d'Orbigny in Ramon de la Sagra, Histoire physique, politique

et naturelle de l'ile de Cuba, MoUusques, vol. II, p. 70.
Clioidea (part.) Gegenbaur, Untersuchungen über Pteropoden und Heteropoden, p. 212.
Cliidae (pai't.) Woodward, A Manual of the Mollusca, p. 208.

PneiiiHoderinonidae (part.) H. and A. Adams, The Genera of recent Mollusca, vol. I, p. 62.
Pneiimodcnnidae Bronn, Die Klassen und Ordnungen des Thierreichs, Bd. III, p. 645.
Pnciiinodenimcfa Troschel, Das Gebiss der Schnecken, Bd. I, p. 56.
Pnenmoderniatidac Dall, Description of sixty new forms of Molluscs from the West

coast of North America, Americ. Journ. Conch., vol. VI, p. 139.
Puciimojiodcnnatidae Pelseneer, Challenger Report, LVIII, p. 11.

i) Untersuchungen über Pteropoden und Heteropoden, p. 95 — 97, pi. V, fig

2) Spolia atlantica, p. 174.

3) Zool. Anz., Bd. XXVI, p. 92—99.

4) Ibid., p. 410 — 412.
SIBOGA-EXPEDITIE LU.

-'S'

L l B R

\ ^/, . -te. t

66

The characters of this family, which iiicludes a rather large number of species, were
established by Pelseneer. According to his researches and those of Boas, three genera may be
properly distinguished :

1 . Dcxiobrancliaca Boas ').

2. Spongiobrancliaca d'Orbigny ').

3. Pneuinouodcriua Cuvier '').

These three genera are all characterised by the presence of suckers on the ventral side
of the buccal cavity and of a gill on the right side.

If the genus ScJiizobraclnum Meisenheimer ') really belongs to this family, the possession
of a lateral gill is no longer characteristic of the Pneumonodermatidae, and so only the suckers
remain, either situated on buccal appendages or directly inserted on the ventral wall of the
buccal cavity. I deern it, hovvever, better to await Meisenheimer's extensive monograph on the
Gymnosomata of the Valdivia Expedition, before it can be ascertained with certainty whether
Schizobrachüiiii must be referred to the Pneumonodermatidae or not.

Of the four genera above named, only one was represented in the material coUected
by the Siboga. It is the genus ;

Pneumonoderma Cuvier.

1804. Pncumoderma Cuvier, Mémoire concernant Tanimal de l'Hyale, etc, Ann. Mus. d'Hist.

Nat. Paris, vol. IV, p. 232.
18 10. Pneumodertiia Péron and Lesueur, Histoire de la familie des Mollusques Ptéropodes,

Ann. Mus. Hist. Nat. Paris, vol. XV, p. 65.
18 15. Pneiimodeniiis Oken, Lehrbuch der Zoölogie, Bd. I, p. 326.
18 15. Aegle Oken, Ibid., p. 326.

18 17. Pneutiiodennoii Cuvier, Le Règne animal, vol. II, p. 380.
1846. Pneiiinonodcnna Agassiz, Nomenclator Zoologicus, Index, p. 299.

1855. Pncifinouodennuvi Herrmannsen, Indicis generum Malacozoorum primordia, vol. I, p. 309.
1879. Cirrifer Pfefter, Übersicht der wahrend der Reise um die Erde auf S. M. Schift"

"Gazelle" und von Hrn. Dr. J.\GOR gesammelten Pteropoden, Monatsber. Ak.

Wiss. Berlin, p. 249.

This genus is chiefly characterised by the presence of twro acetabuliferous buccal
appendages, the suckers of which do not increase in size from the base of the appendage to
lts distal extremity — and by the great development of the lateral and the posterior gill.

After the investigations of Boas '') and Pelseneer ") we now know six species of this
genus. Most of the forms, described by authors previous to the above-mentioned zoologists, were
either identical with other species already known or too insufficiently characterised. Some of

i) Vuilaufige Mittheilung über einige gymiiosomea Pteropoden, Zool. .\nz., Jahig. V'III, p. 688.

2) Voyage dans rAmérique meridionale, vol. V, p. 130.

3) Mémoire concernant l'animal de l'Hyale, etc, Ann. Mus. d'Hist. Nat. Paris, vol. IV, p. 232. It has not become clear to
me, why Pelsexeek has used the name P/witnio/ioiicrnia and not Pncttmodermon.

4) Zool. Anz., Jahrg. XXVI, p. 410 — 412.

5) Spolia Atlantica. p. 151 — 155.

6) Challenger Report LVIII, p. 23 — 32.

67

these forms I shall have lo discuss further on, as they were oblained within the area of
exploration of the SiboCTa.

The material of ihis expedition contains three species, two of which are new. One
species, recorded from the Ivisl-lndian Arrhipelago has not been obtained.

I mav lay stress on tiie fact that it is often very difficuU to distinguish the species
from eacli other. The body being strongly contracted, it is by no means easy to discover the
exact shape of the lateral and tlie posterior gill; and the buccal appendages can be examined
generaUy only by dissection of the head-cavity, in which they are retracted. Added to this
the excessive smahness of some species (not yet 2 mm.), one can understand the difficulty
with which the systematic classification of Pnetiinonodervia is connected.

I . PncniiionoderDia pcroni (Lamarck).

327-

18 15. Aegle cucullata Oken, Lehrbuch der Zoölogie, Bd. I, p.

1819. Pneiimodcruion pcroni Lamarck, Histoire naturelle des Animaux sans Vertèbres, vol.

VI, p. 294.
1887. Pneuinodeniia pcroni Fischer, Manuel de Conchyliologie, p. 423.
1887. Pncnuionodcnna pcroni Pelseneer, Challenger Rep. LVIII, p. 29, pi. II, fig. 2.

Living animal:

Stat. 109. Pulu Tongkil, Sulu Archipelago. i spec.

Only one specimen was caught during the whole cruise of the expedition. It is very
contracted ; the skin is phcated in large folds and of a greyish colour. In the shape of the
gills, and in the disposition of the acetabuhferous appendages, the specimen entirely agrees
with the descriptions of BoAS and Pelseneer. The length Is only 8 mm.

*2. PnaLmonodcriiia incditcrranc2iiii (van Beneden).

183S. Pncuinodcnnon mcditerrancum van Beneden, Note sur une nouvelle espèce de Pneumo-

derme, Mém. Acad. Sci. Brux., vol. XI, p. 13, pi. III, figs. i — 2.
1852. Pncnniodcrmon pcronii (part.) Souleyet, Voyage de la Bonite, vol. II, p. 274, pi. XIV,

figs. 13, 14, 16.
1852. ? Pncumodcrinon pcrojiii (part.) Rang, Histoire naturelle des Mollusques Ptéropodes,

pi. XI, figs. 14 — 19.
1855. Pncjimodermon mediterrancuin Gegenbaur, Untersuch. über Pterop. u. Heterop. p. 213.
1859. SpongiobrancJiea austrahs (part.) Chenu, Manuel de Conchyliologie, vol. I, p. 116, fig. 509.
1873. Pneumodernion peronii Costa, Pteropodi della Fauna di Napoli, p. 22, pi. V, fig. i — 3.
1886. Pncumodcrinon inacrocotylum Boas, Spolia atlaiitica, Bidrag til Pteropodernes Morfologi,

etc, K. dansk. Vidensk. Selsk. Skr., 6 Raekke, Bd. IV, p. 152.

1886. Pneuiiiodeniion andebardi Locard, Prodrome de la Malacologie frangaise, Mollusques

marins, p. 19.

1887. Fncuiiiodcniia vieditcrraneum Fischer, Manuel de Conchyliologie, p. 423.

1887. Pneumonodcrma mediterraneuin Pelseneer, Chall. Rep. LVIII, p. 26, pi. I, fig. 8. pi. II, fig. i.

According to Boas, this species has been caught in the Indian Ocean (5°24'S., 87° 56' E.
and 10° S., 104° E.) and in the China Sea (16° N., 11 5° 20' E.).

68

MuNTHE recorded ^) it (also under the name of Pneitinoderinon inacrocotyhiin) from
"Javasjön" (von Schéele, 1885). Notwithstanding its occurrence in the East-Indian Archipelago
has been ascertained, the Siboga Expedition did not succeed in collecting it.

Many authors have confounded this species with the foregoing one. Indeed, the confusion
in the exact discrimination of Pu. pcroni, vicdUerraneuni and violaccum existed up to the time
of BoAS and Pelseneer.

3. Pnciunonoderiim hctcrocotyhtiii n. sp. (PI. V, figs. 118 — 119).

Stat. 143. i°4'.5 S., i27°52'.6E. i spec.

Body: Strongly contracted ; it seems, however, rather short. Foot of moderate length.

L a t e r a 1 g i 1 1 : short, with fringed lateral somatic crest.

Posterior gill: dorsai and ventral side of the quadrangular crest fringed ; radiating crests
well developed, each of them bearing on either side five or six fringes, which are subdivided.

Buccal appendages: small with a great many suckers, distributed in the following
manner : on either side of the base is situated a bundie consisting of about seventy-five very
small suckers. In the middle of the acetabuliferous appendage about thirty suckers on very long
peduncles are inserted. The shape of these suckers is very peculiar, as they are much elongated,
with thin walls. This whole group somewhat resembles a colony of Vortkclla or Epistylis.

Hook-sacs: strongly developed, the inner sac reaches only half the length of the
outer one. About twenty strong hooks, strongly bent.

R a d u 1 a : not investigated.

Colour: yellowish, head dark (spirit-specimen).

Length: 5 mm.

4. Pnciiiiionodernia pyginaciim n. sp. (PI. V, figs. 120 — 122).

Living animals:

Stat. 141. i°o'.4S., I27°25'.3E. i spec. (young).

Stat. 144. Damar Islaiid. i spec.

Stat. 165. Daram Island. i spec.

Body: short. Foot rather large, not tapering.

Lateral gill: very small, with fringed lateral somatic crests.

Posterior giH: Dorsai and ventral side of the quadrangular crest fringed ; each
radiating crest bears on its median side two very small fringes, not subdivided.

Buccal appendages: short with about eight suckers; the size of which does not
increase from the base to the distal extremity. It is very difificult, even in microscopical
examination, to make out the exact number of the suckers, the whole animal scarcely
measuring 3 mm.

Hook-sacs: very much developed, extending as far as the posterior extremity of the
body. About forty large hooks in each sac.

l) Pteropoder i Ups. Univ. Zool. Mus., Bih. till K. Svensk. Vet. Akad. Handl., Kd. 13, afd. IV, n» 2, p. 32.

69

R ;i d u 1 a : not investigated.

CdliMii-: as ih(; foregoing species.

Lengt h: the largest specimen measured 3 mm.

Re mark: The specimen of Stat. 141 shows round its aboral pole a thickened white
margin, indicating a postcrior cih'ated ring. The fringes on the radiating crests of the posterior
gill are not formed yet. As the buccal appendages of this specimen exhibit the same number of
stickers as those of the two other specimens, I think this larval form may be identical with them.

Perhaps two other larvae from Stat. 165 may be assigned to this species. The
length is 2 mm. The foot is smaller, more pointed. Gills are wanting, but some traces of two
ciliated rings are visible. First I regarded these small specimens as some Spongiodranckaea,
but this view is contrary to the form of the acetabuliferous appendages (as in Pu. fiygmaetim),
and also to the rather strong development of the hook-sacs which contain many long, slender
hooks. At any rate these specimens (fig. 123) are larvae of a Pneuinonoderina.

In the literature two species have been described as belonging to Pnciiinonoderina ; but
these descriptions are very insufficiënt. We ma)-, however, draw attention to these forms, as
they were obtained in the harbour of Amboina.

One of them, '^ PnciiDwdervion ruber' Quoy et Gaimard ') may be a Clionopsis as Boas
thought"); but the presence of a lateral gill speaks against this opinion. As "variété" of this
species Quoy and Gaimard described ^) some forms which are very likely Pneuiiwnodcrina, but
about which nothing can be decided.

"■ Pnetimoderinon pellucidus" of the same zoologists ^) seems to be a Clionopsis"); but
here too a lateral gill is figured. lts systematic position must therefore remain uncertain.

It is very unfortunate that the type specimens of these interesting forms are lost, so
that any discussion about them is nothing but conjecture.

Anatomical Remarks.

The anatomy of the Pneumonodermatidae has been amply studied by Pelseneer*) whose,
very accurate researches will be the base of our knowledge with regard to the anatomy of
the whole family, and, indeed, of all the Gymnosomata.

I had only little material for examination, viz. some s\yQC\m&ns oi Pneumonoderma mediter-
raneiuii from Naples (kindly presented by Dr. Nierstrasz), of Pu. peroni (Leyden Museum),
of Pn. violaceiiin (Amsterdam Museimi), and of Spongiobranchaea aitsfralis (Utrecht Zoological
Museum). As only the representatives of the first named species were sufiiciently preserved, I
have studied those particularly.

It seems quite unnecessary to me to enlarge upon the researches of previous authors

i) Voyage de 1'Astrolabe, vol. II, p. 389, pi. 20, figs. 19 — 20.

2) Spolia Atlantica. p. l-i.

3) Op s. cit., p. 390, pi. 20, figs. 21—24.

4) Op s. cit., p. 390, pi. 28, fig. 25.

5) This opinion has been expressed by Boas, Spolia atlantica p. 171.

6) Challengev Rep. I.XVI, p. 38—45.

70

(CuviER, VAN Beneden, Soulevet and Gegenbaur), as Pelseneer already gave a criticism about
them. For conciseness' sake, I believe it will be better to omit the facts, already known ; and
so I shall confine myself to a few remarks on the nervous system, in which I do not agree
with Pelseneer's description ').

The nervous system of the Pneumonodermatidae is chiefly characterised by :
i" the rather long connectives, the result of which is that the various ganglia are distinct, and

not fused together.
2" the asymmetry of the visceral ganglia (the right is the smaller one), also expressed in the

nerves proceeding from them.
3" the second anterior pedal commissure.
4° anastomosing nerves.
I. The cerebral ganglia are rounded in Pneiuuonodcrma (PI. \", fig. 124, c), transversely
elongated with distinct commissure in Spongioóraiic/iaca^ quite as Pelseneer already affirmed.
The connectives by which they are connected with other ganglia have been exactly
described by Pelseneer : in my hgure the buccal connectives are not indicated, in order to avoid
complication. The cerebro-pedal («), and the cerebro-pleural connectives ((:5) are, however, visible.
A large number of nerves issue from the cerebral ganglia. First the posterior
tentacle is innervated by two nerves, the lateral and posterior of which (i)is the optie nerve,
exhibiting an elongated ganglionic swelling at its base. The second nerve, more medial and
anterior (2) is the olfactory nerve. Both these nerves terminate in ganglionic swellings, almost
juxta-posed, and a little before these ends an anastomosis comes between them, which shows
equally an elongated enlargement. Souleyet whose figures ") are by far the best among all
those of former researches, has not seen this anastomosis, but it was discovered by Boas^).
Ventrally to the origin of the optie nerve a slender nerve (3) passes to the otocyst.
This innervation was seen by Pelseneer *) in Spongiohrajichaea.
F'rom the anterior part of the cerebral ganglia arise :
i" a rather strong nerve (4) to the labial tentacle. In SpongiobrancJtaca^ which has, as
one knows, the anterior tentacles well developed, the innervating nerve is stronger,
conformable to this circumstance.
2" a complex of three nerves (5 — 7), the function of which I could not clearly make out.
This complex, however, innervates (according to Pelseneer) the proboscis, the lips
and the buccal appendages. A common trunk from which two or perhaps the three
nerves arise, I could not observe. Pelseneer declares that the nerve to the anterior
tentacle proceeds from a common trunk with another nerve to the buccal appendages,
but I must deny the truth of this, also with respect to Souleyet's statement''); besides,
these two authors have not seen one of the two nerves (from the anterior side of
the cerebral o-ang-lia) which arise near the median line.

i) Op. cit., p. 41—45, pl- IV, fig. 9, pi. V, figs. 1, 3.

i) Voyage de Ia Bonite, vol. II, p. 268, pl. XV, figs. 29, 30, 32, 34, 35.

3) Spolia aüantica.

4) Op. cit., p. 42, pl. V, fig. 3.

5) Op. s. c, p. 268, pl. XV, figs. 30, 33.

7ï

II. The buccal ganolia are juxta-posed, but yet distinct and not fused together as van
Beneden ^) pretends. As to their exact shape and the nerves I may refer to Souleyet -)
and Pei.seneer ■').

III. The pedal ganglia have been accurately described by Pelseneer-, I have only to remark
that in Pneumonodernia and Spotigioóranchaea the anterior pedal commissure (PI. V,
tig. 125,(7/.) is ratlier long and bent into a sharp angle.

Here too many nerves may be distinguished (fig. 125).

From the anterior side of each pedal ganglion arises a strong nerve (8), ramifying
into the foot. Pelseneer has seen two nerves, somewhat smaller, the lateral of which inner-
vates the fins, the median the foot.

From the lateral side, a little more ventrally two nerves proceed (9, 10). The
lateral nerve anastomoscs with a branch of the median one ; this fact seems not to have
been observed yet.

A little posterior to these nerves the rather strong cerebro-pedal connective {a)
branches off.

From the posterior side of each ganglion, again two nerves issue (11, 12) which pass
to the fins; the lateral nerve soon divides into three, one of which is connected with the
median by an anastomosis. Pelseneer notes three nerves, the onter of which anastomoses
with a nerve of the pleural ganglion ; this anastomosis is also shown by Souleyet. Perhaps
it has escaped my notice, but at any rate the anastomosis between the two pedal nerves
has been mentioned by Souleyet *) only. According to Pelseneer, the posterior pedal
nerves innervate the cervical region ; I believe, however, that they pass to the fins.

A pleuro-pedal connective is not visible externally, as the two ganglia are placed
very close together.

IV. The pleural ganglia are the smallest of all and almost circular. A strong connective goes
from the posterior side to the visceral ganglia (fig. 124, //:-.), wdiile from the anterior
dorsai side the cerebro-pedal connective proceeds (/5). At the point of origin of this connective
two nerves arise (13, 14), innervating the neck. Pelseneer has only seen the outer nerve;
I have already told, that the anastomosis, mentioned by him, with a pedal nerve, has not
been observed by me.

V. The visceral ganglia (fig. 124, z<) are remarkable by their asymmetry, the left being the
larger. Just where the connective to the pleural ganglia arises, three nerves (15, 16, 17)
originate, supplying the visceral sac; a branch of the right lateral nerve innervates the
osphradium. From the left visceral ganglion (and not from the right as Pelseneer says,
through a slip of the pen) two nerves pass to the viscera ( 18, 19). Pelseneer records only one
visceral nerve from each ganglion to the envelopment of the body; besides, these nerves arise,
according to him, froiu the ganglion itself, and not from the transition into the connective.

1) Recherches anatomiques suv Ie PiuttiiioJermon violacciiin d'Orb., Méni. Acad. Sci. Brux., vol. XI. p. 46, pL I, fig. 3.

2) Op. s. c, p. 269, pL XV, figs. 31, 33, 38.

3) Op. s. c, p. 44—45-

4) Op. s. c, pL XV, fig. 37.

72

Finally I wish to remark, that the absence of well-preserved material may be my only
apology for the insufficiënt manner in which I could tracé out the innervation of the various
orcans. As to the eang-lia and the nerves arisin»- from them, I can, however, answer for the
accuracy of my description.

When nothing else is noticed, the species studied is Pnciiuionodcnna incdiierra7ieiini.

Family II. Clionopsidae.

1855. Clioidea (part.) Gegenbaur, Untersuchungen über Pteropoden und Heteropoden, p. 212.
1859. Pneiivioderiuonidae (part.) H. and A. Adams, The Genera of recent Mollusca, vol.
II, p. 613.

1862. Clionidae (part.) Bronn, Die Klassen und Ordnungen des Thierreichs, Bd. III (2), p. 645.

1863. Clionacca^lpart.) Troschel, Das Gebiss der Schnecken, Bd. I, p. 54.
1873. Cliiiopsidci Costa, Pteropodi deila Fauna di Napoli, p. 24.

1887. Clionopsidae Pelseneer, Chall. Rep. LVIII, p. ■},i.

18S9. Cliopsidae Dall, in: Bullet. U. S. Nat. Mus., n" ij , p. 82.

The characters of this family consist chiefly in a very long retractile proboscis, without
buccal appendages, a quadrangular posterior gill, while the lateral one has disappeared.

A specimen, caught by the Siboga Expedition did not exhibit, however, any tracé of
a posterior gill.

Only one genus is known.

Clionopsis Troschel.

1854. Cliopsis Troschel, Beitrage zur Kenntniss der Pteropoden, Arch. f. Naturgesch., Jahrg.

XX (i), p. 222.
1S55. Clio (part.) Gegenbaur, Untersuchungen über Pteropoden und Heteropoden, p. 212.
1862. Clionopsis Bronn, Die Klassen und Ordnungen des Thierreichs, Bd. 111(2), p. 645.

Up to the time of Boas only one species was known. Boas himself described a second
species; and a third one was procured by the Challenger Expedition. I shall describe a new
species further on.

*i. Cliotiopsis grandis Boas.

1885. Fneumodervion pcronii Verrill, Third Catalogue of the Mollusca, added to the Fauna

of the New England Coast, Transact. connect. Ac. Arts and Sci., vol. VI, p. 431.

1886. Cliopsis grandis Boas, Spolia atlantica, K. dansk. Vidensk. Selsk. Skriv., 6 Raekke,

Bd. IV, p. 170.

1888. Clionopsis grandis Pelseneer, Chall. Rep. LVIII, p. 136, pi. II, figs. 7 — 8.

According to Boas, this species has been recorded twice from the China Sea (2°4'X.,
106° 50' E. and 3°3o'N., 107° E.). Very probably it occurs in the East-Indian Archipelago,
but it has not been found by the Siboga Expedition.

73
2. C/iojiopsis niicroccphalns n. .s|). (PI. V, figs. 126 — 128).

Living animal:

Stat. 259. 5° 29.2 S., 132° 52'. 5 E. I -spec.

Body: elongatexl, truncated at the posterior end. Skin without pigment, transparent,
with a great many small, brown glands, which are placed in groups of three or four together.
Two systems of crossing Hnes (nuiscular fibres) are visible on some parts of the skin. Yisceral
nucleus extending to the posterior extremity. The connective tissue, consisting of branched cells,
between the nucleus and the skin especially well developed. The body is somewhat compressed,
showing a constriction in the anterior part, beneath the fins. I have seen no dorsal spot.

H e a d : small ; neck short.

Foot: the anterior lobes are thick, and nniscular; posterior lobe absent, as in the
other species of the genus. Tubercle well developed, oval, consisting of five or six lamellae,
longitudinally placed. Anterior lobes terminating distally in an acute angle.

Fins: small, rounded (they are strongly contracted in the single specimen collected).

Posterior giH: wholl\- absent ; at the aboral pole, however, of the body at the
place of the gill, the genital gland is situated, at the outside of the body, somewhat turned
to the right. It consist^ of numerous rounded follicles which in microscopical examination
show some ova with a ver\- large nucleus, and a great many rounded cells, imbedded in
fibrillar connective tissue. A thin, brownish-coloured efferent duet arises from the gland towards
the accessory genital glands, situated ventrally. The curious arrangement of the genital gland
at the outside of the body seems perhaps abnormal (due to fixation.?), but it is more probable
that it is the normal position in the living animal, as I could not observe any rupture in
the body-wall, and the internal organs did not exhibit any displacement.

Hook-sacs: very shallow, each with about twenty hooks, bunch-like arranged.

Radula: the formula is 4.1.4. The median tooth is tricuspid, as in other Clionopsidae,
but at both cornua of the semi-lunar tooth a small projecture may be seen (fig. 128). The
lateral teeth are well developed, with broad base and strong beak, slightly bent at the extremity.

Proboscis: very long, laid in wide windings, when invaginated ; about as long as
the animal itself. It occupies the whole anterior portion of the visceral mass, while the posterior
part is filled up by the stomach and the liver.

C o 1 o u r : yellowish, nucleus visible as a dark, thick bar (spirit-specimen).

L e n g t h : 15 mm.

Remarks: The general form of the body, the transparency of the skin with its systems
of crossing lines, the absence of a gill whose function seems to be adopted by the genital
eland, the longritudinal lamellae in the tubercle between the anterior lobes of the foot, the
small number of hooks in the hook-sacs, and the formula of the radula — alle these peculiarities
are sufficiënt to take it for granted, that the specimen of the Siboga is a new species. It
seems even admissible to regard it as the representative of a new genus (characterised by the
absence of a gill, and the conformation of the genital glandj, but as I could study only this

SIEOGA-EXPEDITIE Lil. 'O

74

single specimen, I do not venture to erect a new genus on such negative and perhaps
abnormal characters.

Pelagia alba Ooy and Gaimard ') has some resemblance with this form, but differs
from it in the great development of the head. Tlie naturahsts of the Astrolabe collected this
Pelagia in the harbour of Amboina.

Anatomical Notes.

Unfortunately I could not obtain a single specimen for examination ; and the wish to
preserve the specimen of the Siboga Expedition has prevented me from dissecting it. To the
above-mentioned notes about this specimen I may add, that the visceral mass is enveloped by
a rather thick whitish membrane, with the same peculiar numerous openings as has been
recorded in Cyinbnliopsis and Glcba \ probably, respiration takes place by means of these
openings. The anus opens at the right side beneath the fin, and the heart is placed far back.
These facts comprise in a few words all I could discover about the anatomy.

Family III. Notobranchaeidae.

1886. NotobrancJiaeidae Pelseneer, Description d'iin nouveau genre de Ptéropode Gymnosome,
Bullet. Sci. Dép. Nord, p. 224.

As some specimens of the genus Notobranchaea have been found in the Siboga-collection,
I am able to complete the description, given by Pelseneer.

Body: contracted and pointed at the posterior extremity; visceral mass not reaching the
aboral pole. No dorsal spot. Head broad and svvollen, distinctly separated from the short neck.

F o o t : posterior lobe tapering ; anterior lobes terminating distally in an acute angle ;
a small tubercle between them.

Fins; large, rounded.

Posterior gill: three longitudinal crests, meeting at the posterior extremity of the
body, and extending over the posterior third of its length; one crest is median and dorsal,
and bears fringes (in the adult specimen at least), the lateral crests (right and left) are simple.
A lateral gill is absent.

Buccal appendages: short, thick buccal cones of the same external appearance and
of nearly the same structure as in Clionc.

Radula: strongly developed, with many teeth in a transverse series, but without
a median tooth.

Hook-sacs: short and shallow, with a few hooks, arranged in a bunch at each side
of the radula.

J a w : absent.

l) Voyage de IWslrolabe, vol. II, p. 392, pi. 28, figs. 7 — 9.

75
Only one gemis is known.

Notobranchaea l'elsenecr.

1825. ? Clio (part.) Rang, Description d'uii nouveau genre des Ptéropodes et de deux espèces
nouvelles du genre Clio, Ann. d. Sc. Nat., sér. I, vol. V, p. 286.

1863. Clio (part.) Macdonald, On the Zoological Characters of the living Clio caudata, Trans.
Roy. Soc. Edinb., vol. XXIII, p. 186.

1886. Notobranchaea Pelseneer, Description d'un nouveau genre de Ptéropode Gymnosome,

Bulkt. Sci. Dép. Nord, p. 224.

This genus was established by Pelseneer, but the little material at his disposal did not
enable him to give a complete diagnosis.

The characters of this genus are the following, according to my own researches:

Buccal co nes: two pair of short cephaloconi, disposed in the same manner as in
Clione^ viz. inserted on the wall of the buccal cavity, at the outside of the ''false lips", while
a hood circumscribes an opening, corresponding with the true buccal aperture in the Pneumono-
dermatidae and Clionopsidae. Pelseneer ascribes to Notobranchaea only one pair of cephaloconi,
but I have seen two pair of them in the same species that was studied by him. In this respect
]\Iacdon.\ld is right whose description, for the rest, is too obscure and too short as to
recognize with certainty the species to which his "trigonal tailed Clio" belongs.

Posterior gill: the fringed dorsal crest is a very complicated winding fold of the
skin. I have seen a larva (most probably belonging to the same genus) in which the three
crests consist of a great many dermal glands closely grouped together, and in which a gill
properly so called is not present. I shall refer to this larva again.

R a d u 1 a : without median tooth, quite the same as has been described above for the family.

Hook-sacs: short, with a few hooks.

The family of the Notobranchaeidae shows very great resemblance with the Clionidae,
and it mav be expected that when more species will be discovered, these two groups will have
to be united to a single family.

Of the two sjsecies hitherto described, one was found by the Siboga.

I. NotobrancJiaea hiopinata Pelseneer. (PI. V, figs. 129 — 135).

1887. Notobranchaea inopinata Pelseneer, Chall. Rep., LVIII, p. 40, pi. III, figs. 5 — 6.
Stat. 144. Damar Island. 3 spec.

Body: ovate, posterior extremity much contracted in the pre:ierved specimens. Head
broad, bilobated, distinctly .separated from the neck. Pigment in one specimen chiefly distributed
on the right side ; in the two other specimens it is entirely absent.

Foot: the anterior lobes (fig. 133) are rather broad, free in their posterior half. The
tubercle is rounded. Posterior lobe short, but pointed with a longitudinal ridge.

Posterior gill: consisting of a much wound fold, without real fringes (fig. 134).

76

Buccal appendages: two pair of buccal cones (fig. 131 — 132).
Labial tentacles: small, situatecl about as much clorsally as ventrally.
Radula: the formula is 8.0.8 (fig. 135).

Length: the pigmented specimen measures 6 mm., the two other specimens are 5 mm.
Colour: the pigmented specimen is yellow; the other specimens are greyisli (spirit-
preservation).

Observation: I have tried to give a sufhcient description of the Siboga-specimens,
in which I could not observe any specific difference from the Nofodraiichaea inopinata of
Pelseneer. This species was found by the Challenger, east of Japan (35°29'N., 179° 50' W.)
and afterwards it has been recorded ') from Port Jackson Heads, New South Wales.

To the Notobranchaeidae, and probably to Notobranchaca a curious larva must be
referred (PI. V, figs. 136 — 138). This larva was found at Stat. 36 (7°38'S., 11 7° 31' E.).

The length is only 2 mm. A great many glands are scattered all over the body, but
at the place, where the three crests of the ])Osterior gill are situated in adult specimens, the
glands are very closely grouped together, and this accumulation also occurs at the posterior
extremity (fïg. 138). The two posterior ciliated rings are still discernible as thin white lines.
The whole body is more pointed, the visceral sac does not occupy the posterior third of the
body. The fins are rounded and broad ■, the anterior lobes of the foot are free for half their
length, and the posterior lobe is pointed — quite as in Notobranchaea inopinata. The neck is
shorter and broader (perhaps due to stronger contraction). The nuchal tentacles are placed
far back. The proboscis is somewhat evaginated and shows also two shallow hook-sacs, with
bunches of hooks By clearing the specimen in glycerin, I could observe two pair ot buccal
cones. The skin is without pigment and of a grey colour (alcoholic preservation).

A n a t o m i c a 1 R e m a r k s.

The anatomy of A^otobranchaca has never been studied until now. Though I could not
push my researches so far as to give a complete anatomical description, I shall try to indicate
a few things which I have observed.

The external appearance of the animal has been already described.

The proboscis possesses false "lips" as in Clionc, the buccal appendages being therefore
inserted around the secundary mouth. The cephaloconi number two pairs. Their internal
structure I could unfortunately not make out, as the dissected specimens did not clearly show
delicate histological details. I could only see on transverse sections : (ij a micldle muscular
region, consisting of an exterior layer with annular fibres and an interior one with longitudinal
fibres, (2) an internal region formed of glandular cells, while the (3) epithelial investment
nothwithstanding I took much care to investigate it, has remained indistinct. Probably, the

l) Brazier, Australian Museum Catalogue (1892), n" 15, Pit. II, Pteiüpoda, p. 42.

77

structure <if the cones will not diffor <;reatly from that of the cephaloconi in Clioiie^ as described
by Pelseneer ').

The radiila is strontjly develop(>d, without median tooth. The: hook-sacs are short; each
hoek (one cell) bears a large nucleus at its base, while the horny layer is only found at the
free periphery of the tapering celL

\&x\ rcmarkable are some bladder-like organs around the oesophagus, and reaching as
far as the stomach. Thuugh these bladders open sometimes in each other, a communication
with the digestrive tract or with any other organ does not exist at all. They are therefore
similar to the "Schlundblasen", noticed by Meisenheimer ') in Pteroceanis^ and about which an
extensive description will soon be published.

The structure of these sacs is the following (PI. V, fig. 139): a layer of epithelial
cells is found peripherically ia) with very flat, small nuclei, and at the inside of this layer, a
region of glandular cells (5) with large nuclei and with prolongations into a reticulated network
of branched cells (c) with very small nuclei. The inner part of the sac is probably filled with
secretion of the glands. It may be noted, that the epithelial layer at the outside does not
always occur.

I have seen no salivary glands.

As to the rest of the digestive tract, I have observed no clifferences from that of other
Gymnosomata. The ciliated villi of the oesophagus end into the stomach, which is rather
wide and wholly unarmed. The intestine is short and goes directly upwards, opening beneath
the right fin.

The shape of the generative organs too is quite similar to that of other Gymnosomata
(fig. 140). The gonad [g] is rounded and occupies the posterior part of the visceral mass.
This gland consists of the same hermaphrodite lobules as in the preceding families. A
thin efterent duet {d), soon enlarging in its course, arises from the gonad and reaches the
accessory genital glands. The albuminiparous [b) and muciparous glands (a) have a different
aspect on their surface, the plicae of the former being smaller and more numerous. A "vagina"
(Gegenbaur) proceeds from the dorsal surface (t') of the accessory genital glands. The penis,
coiled up in the head cavity, exhibits on its surface (when invaginated) at the right side, a
broad, winding band, consisting of very high epithelial cells (fig. 141 j.

The disposition of the ganglia in the central nervous system scarcely presents anything
remarkable, as far as I could perceive. The cerebral ganglia are closely placed together above
the oesophagus, but show a distinct commissure. The ganglia below the oesophagus are
arranged in the same manner as in the Pneumonodermatidae; the visceral ganglia too are
asymmetrical, the left being the larger. From this ganglion issue two nerves, the right visceral
cfangflion is destitute of such nerves.

i) The cephalic appendages of the Gymnosomatous Pteropoda and especially of Clione. Quarterly Journal Mier. Se., vol. XXV

(1885). p. 491-509, pi- >^>^>^v.

2) Über eine neue Familie der gymnosomen Pteropodea aus dem Material der Ueutschea Ïiefbce-Expedition (Pteroceaniden),
Zool. Anz., Jahrg. XXVI, p. g6.

78

Family IV. Clionidae.

1840. Clionidae Gray, Synopsis of the contents of the British Museum, p. 86.

1846. Clionoidae (part.) Agassiz, Nomenclator Zoologicus, Index, p. 90.

1S50. Clioiieidae Gray, Catalogue of the Mollusca in the collection of the British Museum,

prt. II, Pteropoda, p. 35.
1853. Pneitmodermidae (part.) d'Orbigny, in: Ramen de la Sagra, Histoire physique, politique

et naturelle de l'ile de Cuba, Mollusques, vol. I, p. 70.

1855. Clioidea (part.) Gegenbaur, Untersuchungen über Pteropoden und Heteropoden, p. 212.

1856. Cliidae (part.) Woodward, A Manual of the Mollusca, p. 208.
1863. Clionacea (part.) Troschel, Das Gebiss der Schnecken, Bd. I, p. 54.

As one knows. this family is characterised by the much elongated body, the absence
of a gill and by the cephaloconi, inserted at the outside of false Hps. It is very closely related
to the family of the Notobranchaeidae, but differs from it in the strongly pronounced tapering
of the body, the entire absence of a giil and by a median tooth in the radula.

The foot of the Clionidae resembles much that of the Notobranchaeidae : the anterior
lobes have nearly the same shape, and no tubercle is found between them. The posterior lobe
of the foot, however, is still more reduced, and, as we shall see further on, it is even entirely
absent in the new genus Paraclioiic.

Great confusion has existed for a long time in the systematic treatment of this family.
A rather large number of species, belonging to this family, and having been described nearly
alwaj's under the name of Clio, are insufficiently characterised, and the figures repre.senting
them are generally incomplete. Up to now, however, only one species is well known, viz.
Clione liviacina^ and it wouJd be very interesting to obtain further Information on forms
previously described, but never found again. I may, for the re.st, refer to Pelseneer ^) who
gave a critical systematical synopsis of this family.

Now, to the genus Clione, I can add a new genus, procured by the Siboga Expedition.

Clione Pallas.

1773. Clio (part.) Phipps, A Voyage towards the North Pole, p. 195.

1774. Clione Pallas, Spicilegia zoologica, fase. X, p. 28.
1776. Clio O. F. Muller, Faunae danicae prodromus, p. 226.

1825. Cliodita (part.) Qoy et Gaimard, Description de cinq genres de Mollusques, Ann. d.

Sci. Nat. sér. I, vol. V, p. 74.
1840. Spongiobranchea (part.) d'Orbigny, Voyage dans l'Amérique meridionale, vol. V, p. 132.
1852. Clio (part.) Rang, Histoire naturelle des Mollusques Ptéropodes, p. 77.
1855. Clio (part.) Gegenbaur, Untersuchungen über Pteropoden und Heteropoden, p. 212.
1855. Clio Auctorum.

In Clione the body is much elongated, terminating into a rather thin point. The buccal
cones number from one to three pairs, the labial tentacles are well developed, and the posterior

I) Chall. Kep. I.VIII, p. 41—51.

79

lobe of the fout, thouL;li niucli reduced, is yet present. The fins are pointed, the proximal
anofle extendingf farther tlian the distal one.

Three species may be distinguished. The only specimen in the Siboga-material belongs
tü a new species, a description of which follows here.

I. Clione piinctata n. sp. (PI. V, fig. 142).
Stat. 165. Daram Island. i spec.

Body: pointed at the back, not much elongated.

H e a d : depressed, rather broad ; neck very short.

Foot: anterior lobes thick, semi-hmar, attached throughout nearly their whole length,
and terminaling into an obtuse angle. Posterior lobe very short, pointed.

Fins: short and broad (but much contracted in the specimen).

B u c c a 1 appendages: there is only one pair of buccal cones, disposed in the ustial
manner. Their shape is cylindrical, not conical as in Cliotie liiiiaci7ia.

R a d u 1 a and Hook-sacs: not investigated.

C o 1 o u r : the skin is transparent and quite colourless ; the visceral mass exhibits a pale
yellowish colour, and so does the head, though here the colour is somewhat darker. The fins
are whitish. Very remarkable are chromatophors, scattered all over the visceral mass and the
head, even over the cephaloconi. The shape of these chromatophors (fig. 143) varies very
much; they are black, and, as I have convinced myself, they are not situated in the skin itself,
but beneath it.

The specimen has been preserved in formol 4°/o.

Length: 4 mm.

Remarks: As I had only one specimen at my disposal, I have not ventured to
investigate the radula and hook-sacs, as dissection would have damaged the animal seriously.
I, therefore, must restrict myself to the indications noted above, in order to distinguish Clione
ptmctata from other species of this genus. The presence of only one pair of buccal cones,
and the occurrence of chromatophors has not yet been recorded in Clione. The skin which
is very thin and wholly transparent, consists of a pavement epithelium of polygonal cells
with smal! nuclei, and of a small number of unicellular glands ; muscular fibres run beneath
this epithelium.

Orov and Gaimard recorded a new species of "Cy/cZ' from the harbour of Amboina.
This form was called by them Clio pyramidalis '), but description and figure are very obscure.
The fins are "ovalaires, largement fixées au corps". I should be inclined to think, that we
have to do with some Aplysia or Xotarchiis. At any rate I wanted to draw the attention
to this form.

i) Voyage de TAstrolabe, vol. II, p. 371, pi. 27, figs. 37.

8o

A n a t o m i c a 1 R e m ar k s.

The anatomy of this genus has been studied by Cuvier '), Eschricht "), Souleyet ^),
Wagner ■'), Pelseneer °) and Schalfejeff ^). I have thought it better to give a few notes with
respect to the central nervous system about which Pelseneer gave a most detailed description.
As I differ froni hini in a few points, I cannot let them pass in silence. I have examined some
specimens of Clionc /iiimcina (Leyden Museum).

The central nervous system of Clionc is constituted like that of the Pneumonodermatidae,
viz. the form and disposition of the ganglia is nearly quite the same. In Clionc, the pleuro-
visceral connective is a little shorter, and the pedal ganglia present a long commissure (which,
however, does not alwaj-s occur).

I. The cerebral ganglia (PI. V, fig. 144) are situated above the oesophagus, and exhibit a
distinct commissure. Three pair of connectives issue from them.

A. From the oesophageal surface of each ganglion a thin connective [bc^ passes to the
buccal orangrlia.

B. From the lateral .side a .strong connective (/^) goes to the pedal ganglion.

C. A little more distally, nearly parallel to the foregoing one a cerebro-pleural connective
[plc] is discernible.

The last two connectives are longer than in the Pneumonodermatidae.

From each cerebral gfanelion several nerves arise.

From the dor.sal part two nerves (i, 2) proceed to the nuchal tentacle. They
are the olfactory and the optie nerve, both ending in a swelling. The optie nerve (2)
exhibits at its base a ganglionic enlargement, readily visible. An attentive exaniination
shows, that it consists of two elongated swellings (fig. 145), each with a large nucleus.
This fact seems not to have been observed before. I could not discover an anastomosis
between the two nerves, but such a connection has been mentioned by Boas ^), who studied
it in Clione.

P'rom the lateral side of the cerebral ganglion, a little ventrally, a nerve (fig. 144, 3)
passes to the otocyst.

I have seen two large trunks arising from the front part of the cerebral ganglion.
The lateral one soon divides into two branches, each of which sends off a slender nerve
to the skin (4, 5). The lateral branch (4) innervates the ventral buccal cone; the median
(5) goes to the labial tentacle. The median trunk equally divides into two nerves (6, 7),

i) Mémoiie sur Ie Clio borcalis. Ann. Mus. crHi.-^t. Natur. vol. II (1802), p. 242 — 249.

2) Anatomische Unteisuchungen iiber die Clionc borcalis (1838).

3) Voyage de la Bonite, vol. Il, p. 275 — 288, pi. XV, figs. i — 17.

4) Die Wirbellosen des Weissen Meeres. Bd. I (1885), p. 89 — 120.

5) The cephalic appendages of Ihe Gymnosomatous Pteropoda, and especially of Clionc, Qiiarterly Jouin. Mier. Sci. (18S5),
vol. XXV, p. 491 — 507, pi. XXXV, and Recherches sur Ie système uerveux des Ptéropodes, .\rch. de Biol., vol. VII, p. 96 — loi,
pi. IV, figs. 1—4.

6) Zur Anatomie der Clionc liniacina. Zool. Anz., Jahrg. XII, p. iSS — igo. y

7) Spolia atlantica, p. 143.

8i

the lateral (6) of whicli inncrvatcs the dorsal buccal cone, while the median (7) supplies
the mitklle cone, aml inoreover sends ofl a sleiidtT thread to tlie false "lips".

According to Pelsenekr, the dorsal and middle cone are supplied by two nerves,
arising froin a comnuin median trunk. He speaks of a latcM'al trunk, innervating the anterior
tentacle and the ventral cone ; besides there is an anastomosis between the nerves to the
ventral and to the middle cone. I could not discover this anastomosis. Finally Pelseneer
mentions a lateral slender nerve, rising independently, to the false "lips". In the main
points agreeing with him, I cannot, however, entirely .share his opinion, as I have explained
above (as regards the anastomosis, and the innervation of the "lips").

II. The pedal ganglia have a triangular shape (fig. 146) and present a long and rather thin
commissure [pecd) between them. In one specimen, however, the ganglia were close
together, and so the commissure was short. The very long anterior pedal commissure {apdc)
issues from the base of the median nerve (8), vvhich proceed from the pedal ganglion, as
Pelseneer already remarked. From the proximal surface of each ganglion one nerve (9)
arises, supplying the fins, and another nerve (10) innervating the lobes of the foot, as the
median nerve (8) does too.

From the lateral part a cervical nerve (11) forms a plexus with another nerve (12)
from the pleural ganglion (fig. 144) I have already tokl that I could not observe this
cervical plexus in Pncuiuonodcriua in which it is said to exist as welk

Finally, from the ventral surface of the ganglion and thus on dorsal view concealed
for the greater part, a strong nerve issues (fig. 146, 13). I could not clearly make out
its destination, but as this nerve passes ventrally to the visceral ganglion, it seems as if
it proceeds from this ganglion. Probably it is this nerve which Wagner ') took for a
visceral one, when he says, that the lateral nerve of the left visceral ganglion in some cases
arises from the pedal ganglion.

The otocysts are placed in the usual manner.

III. The pleural ganglia are in apparent juxtaposition to the pedal ganglia, but a connective
between these ganglia really exists. The only nerve passing from the pleural ganglion
(fig. 144, 12) anastomoses with a pedal nerve and has been mentioned already.

III. The pleuro-visceral connective (fig. 144, plv) is shorter than in Pneiimonoderma. The
visceral ganglia show a scarcely indicated asymmetry, which is distinctly pronounced in
the nerves. From each ganglion a strong nerve ( 1 4) arises ; besides there are two visceral
nerves from the left ganglion (15, 16). The lateral of these nerves (16) is stronger than
the median (15), whose origin is so close to the separation between the ganglia, that a
-slight mistake as Wagner has committed ■), who figured this nerve as having its origin
between the two ganglia, ma\- be readilv for given.

1) Die W'irbellosen des Weissen Meeres, Bd. I, p. loo, pL XI, figs. 4, 11.

2) Op. s. cit., pL XII, figs. I, 12.

SIBOGA-EXPEDITIE Lil.

82

Paraclione n. g.

Closely resembling Clione, but distinguished from it by the absence of the posterior lobe
of the foot, and by a rather long spine in the median tooth of the radula ').

Descriptie n: the body is elongated, but not so much as in Clionc\ terminating into
an obtuse point, separated from the rest of the body by a constriction. Visceral mass not
extending tovvards the extremity, between the visceral mass and the skin branched connective
tissue is well developed, especially on the right side of the body. Head broad, bilobated,
separated from the trunk by a short neck. Anterior lobes of the foot broadly attached; no
tubercle between them ; posterior lobe quite absent. Fins broad and rounded at their distal
extremity. Buccal appendages conical, inserted at the outside of false "lips". Hook-sacs with a
few hooks; no jaws. Radula with a median tooth which shows a slender spine, springing from
the proximal margin of the tooth, but directed distally.

I. Paraclione pelseneeri n. sp. (PI. V, figs. 147 — 152).

Stat. 16. 7° 38' S., 117° 31' E. I spec.
Stat. 213. Saleyer Island. 3 spec.

Stat. 223. 5°44'.7 S., 126° 27'. 3 E. i spec.

Body: as described above for the genus. As may be seen from the figures, the
shape of the animals differs considerably, but this fact is partly due to contraction, partly to
the more or less development of the connective tissue beneath the skin. In one specimen of
Stat. 213 (fig. 14S) this tissue is especially well developed on the head, which is therefore much
larger than in the other specimens. Two specimens of .Stat. 213 and one of Stat. 223 (figs. 148,
149) present chromatophors, disposed in the same manner as in Cluvtc punctata, the skin itself
being therefore quite without pigment and only provided with unicellular mucous glands, chiefly
crowding in the neck, and above the cloacal depression. The point in which the body terminates,
bears beneath its epithelium on the surface, a rather strong layer of annular muscular fibres,
at the inside of which several longitudinal muscles spread over the body-wall. By the layer of
annular muscles is the aboral pole more opaque than the rest of the skin.

Foot: the anterior lobes are broadly attached; in the specimen of Stat. 223 (fig. 149)
these lobes are a little deformed and curled outwards. They are free for about one half of
their length. A posterior lobe is absent.

Fins: rounded at their distal extremity.

Buccal ajjpendages: two pairs, inserted at the outside of false "lips" (fig. 152);
the dorsal is smaller than the ventral, but of course I cannot say whether this difference is a
specific characteristic or a generic one. As the animals are exceedingly small, it is necessary
to make transverse sections through the head, if one intends to e.xamine the disposition of
the cephaloconi.

i) It must be noted, that Macdon.m.d (Tiansact. Roy. Soc. Ediiib., vol. X.XIII (1S63), pi. IX, fig. 3,1') also repiesents the
radula of "CV/o caitdata^ as possessing a median tooth with a long spiiie. Unfortunately, however, the foot has not been described.

83

Rad ui a: with a median looth, which carrics a ratlicr long spine, directed distally
(fig. 1^1 A). The fonnula is 3. i .3; the lateral teeth present a slender shape.

Mook-sacs: short, as in Clioiic\ the hooks have a broad base, and are bent abruptly
at their extremity (fig. 1 5 i B).

J a \v : absent.

Length: the largest specimen measures 3 mm.

Colour: greyish or yellowish ; the chromatophors are black (spirit-preservationj.

Re mark: though the animals are very small, they are no larvae, as no tracé of
ciliated rings exists.

A n a t o m i c a 1 R e m a r k s.

By making a series of transverse sections through one specimen, I have convinced
myself that the anatomy of the onh' representative of this new genus is very much like that
of Clione. The digestive tract does not offer anything remarkable. The anus opens at the
ventral margin of a cloacal depression; at the dorsal margin the osphradium is situated.
The kidney opens immediately beneath this organ. A penis is entirely absent; perhaps this is
another peculiarity of the genus. The gonad is situated ventrally to the liver; a thin efferent
duet without any perceptible swelling in its course opens into the muciparous and albuminiparous
ti^lands, the folds of which consist of a high cylindrical epithelium. A vas deferens with a small
hernia at its base, opens beneath the distal margin of the right fin. The gonad itself is made
up of numerous rounded cells, consisting chiefly of a nucleus and probably spermatids. Some
ova with very large nucleus are found at the periphery.

The central nervous system is arranged in the same manner as in Clione. The pedal
ganglia possess a long commissure too.

Family V. Halopsvchidae.

1850. Cymbiiliadac (part.) Gray, Catalogue of the Mollusca in the collection of the British

Museum, prt. II, Pteropoda, p. 24.
1856. Hyaleidae (part.) Woodward, A Manual of the Mollusca, p. 204.
1859. Eurybidae Chenu, Manuel de Conchyliologie, vol. I, p. 115-
1863. Eiiribiacca Troschel, Das Gebiss der Schnecken, Bd. 1, p. 54.
1887. Eurybiidae Fischer, Manuel de Conchyliologie, p. 426.
1887. Halopsychidae Pelseneer, Chall. Rep., LVIII, p. 52.
1887. Cyvibuliidae (part.) Auctorum.

Among the Gymnosomata the Halopsychidae take an isolated place. Though they
are certainly related to the Clionidae, there is a remarkable distance between these families.
Indeed, the general aspect of the only representative of the Halopsychidae, sufficiently known,
only vaguely suggests the common habitus of the Gymnosomata ; and it is only by means
of more careful examination, that the general characters can be discovered. One can even

84

easily understand the mistake of most zoologists (before Boas and Pelseneer) who considered
these animals as testaceous, and therefore classed them among the Thecosomata.

As to the characters of the family, I may refer to Boas ') and Pelseneer -). Some
inaccuracies of Boas, who mistook the buccal ajjpendages as most authors did before
him, were rectified by Pelsexeer. I must, however, protest against one statement of both
authors, viz. that the posterior lobe of the foot is separated from the fins, as in all
Gymnosomata. I have examined a large number of specimens, but I always found this posterior
lobe connected with the fins (PI. VI, fig. 153,//)- In this respect I agree with Huxley ^^
and Souleyet'').

HalOpSyche Bronn.

1825. Psyche Rang, Description d'uii nouveau genre de Ia classe des Ptéropodes, Ann. d.

Sc. Nat., sér. i, vol. Y, p. 284.
1827. Eiiribia Rang, Description de deux genres nouveaux, appartenant a la classe des

Ptéropodes, Ann. d. Sc. Nat., sér. i, vol. XII, p. 328.
1832. ? Cyrnbulia (part.) Quoy et Gaimard, Voyage de TAstrolabe, p. 376.
1856. Eurybia Woodward, A Manual of the Mollusca, p. 206.

1862. Halopsyche Bronn, Die Klassen und Ordnungen des Thierreichs, Bd. III, p. 645.
1862. Thcceurybia Bronn, Ibid., p. 645.

From the description and figures of OuoY and Gaimard who described a "■ Cymbttlia
norfolkensis'\ it is impossible to decide to which form these indications must be applied. Most
probably a species belonging to the genus in question is meant.

At present only one spjecies is sufiiciently well known, which has been collected in
considerable quantities by the Siboga Expedition. As to the forms PsycJic globitlosa and
Euribia JicDiispherica, both described by Rang, we know too little about them as to express
any opinion regarding their systematic position, but it would be very interesting to obtain
further Information, as the fins in these animals attain excessive development.

I. HalopsycJic gaiidichaiidi (Souleyet). (PI. VI, figs. 153 — 156).

1852. Euribia gaudichandii Souleyet, Voyage de la Bonite, vol. II, p. 253, pi. XIV, figs. i — 6.
1859. Eurybia gaudicliaudi Macdonald, On the anatomy of Eurybia gaudicliaudi, Transac.

Linn. Soc. Lond., vol. XXII, p. 245, pi. XLIII.
1883. Thcceurybia norfolkeiisis Ray Lankester, Mollusca, Encyclop. Brit., 9"' Ed., vol. XVI,

p. 666, fig. 83.

1886. Halopsyche gaudichandii Boas, Spolia atlantica, Bidrag til Fteropodernes Morfologi etc,

K. Dansk. Vidensk. Selsk. Skrift., 6 Raekke, Bd. IV, p. 173, pi. VIII, fig. 119.

1887. Halopsyclic gaudichaudi Pelseneer, Chall. Rep. 'LVIII, p. 55, pi. III, figs. 7 — 9.

Living animals:

Stat. 141. 1° o'.4 S., I27°25'.3E. 28 spec.

Stat. 143. 1° 4'. 5 S., i27°52'.6E. 3 spec.

1) Spolia atlantica, p. 171 — 173.

2) Chall. Rep., LVIII, p. 52 — 53.

3) On the Morphology of the cephalous Mollusca, Philos. Transact. (1S53), pi. IV, fig. 3.

4) Voyage de la Bonite, vol. II, pi. XV, fig. i.

«5

Stat. 14S. o°ï/.6S., I29°I4'.5E. 3 spec.

Stat. 157. o°32'.9S., 130° 14.6 E. 3 spec.
Stat. 172. Betweeii Gisser and Cerani-Laut. 6 spec.

Stat. 185. 3° 20' S., i27°22'.9E. 9 spec.

Stat. 203. 3°32'.sS., i24°i5'.5E. 18 spec.

Stat. 205. Lohio ]?ay, Buton Strait. i spec.

Stat. 216. 6° 49' S., 12 2° 43' E. I spec.

Stat. 243. 4°3o'.2S., 129° 25' E. 2 spec.

Stat. 245. 4°i6'.5S., i30°i5'.8E. 2 spec.

This species was found by the Challenger off Mindanao. It seems very common in the
East-Indian Archipelago, and by far more numerous than any other Gymnosomatous form.

A n a t o m i c a 1 R e m a r k s.

Skin: without pigment, of a yellowish colour. The body-wall is very thick on the trunk,
but not on the head. The animal can entirely retract into its tough envelopment; in this
case two extensions (dorsal and ventral, of which the dorsal is more developed) cover the head
and its cephaHc appendages in such a way, as to form a frontal fissure. In this contracted state
the animal, indeed, suggests at first sight some Cyinbiiliopsis.

The skin is well provided with dermal glands which are visible, even to the naked eye,
as small white spots (in formol-preservation). Transverse sections through the skin show its
structure sufificiently (PI. VI, lig. 154). At the surface is found an epithehum (i) of flat cells
with distinct nuclei ; on surface view these cells appear to be polygonal. Beneath the epithelium
there is a layer (more or less thick) of elastic fibres. In this layer the glands are situated, and
they attain a differentiation which is not found in other Gymnosomata, for aught I know. Vet
they are all unicellular glands, in which a nucleus is always present. Some of these glands are
very small, goblet-shaped (3), while others (4) are larger, more slender and pyriform, the contents
of which absorb much colouring matter so as to become diffusedly coloured. The walls of these
glands are simply membraneous without distinct structure. Finally a third form is represented by
very large glands (2), with a short efferent duet and with granular contents. The walls, when cut
tangentially, show striae, (perhaps they are muscular) crossing one another in several directions.

The layer of elastic fibres between which nuclei are scattered, together with the surface
epithelium, make up the skin (hg. 154, a). Beneath this skin is found the usual layer of
branched stellated cells [b).

Head: the head is e.xtremely small and difficult to distinguish. On the one hand this
is due to the absence of a cephalic hood, on the other to the great development of the
cephalic appendages. As to the latter, the great confusion reigning with respect to a right
interpretation of buccal appendages and tentacles was not cleared up until Pfxseneer came to
the fore-ground. I may therefore refer to his paper.

Foot: the foot is somewhat differently shaped from what is usually found in the
Gymnosomata. The anterior lobes (hg. 153, «/) are free for the greater part; the posterior lobe
(//) is not separated from the fins, but distinctly attached to it. I have already said, that
this statement does not agree with that of Boas or Pelseneer.

86

Fins: these locomotorj- organs are also a little deviating from the usual type. They
are narrow at their base, enlarged at their distal extremity, which is membraneous, especially
in the middle, and exhibits a sinuosity (fig. i53,/).

Digestive tract; The mouth, bordered by false "hps", opens immediately behind
(dorsally to) the anterior lobes of the foot. At the sides of the h'ps the buccal appendages are
inserted. These appendages are long, flattened and very contractible. I have tried to examine
their histological structure, but as neither transverse or longitudinal sections (lo or 5 /j.y..),
nor staining in toto and mounting, has given me sufficiënt results, I think it better to pass over
this structure in silence, rather than to speak of something, about which I could not obtain
absolute certainty as yet.

A protrusile proboscis is quite absent. The oesophagus has a narrow lumen, as its
walls are laid in large folds. — The radula is strongly developed. lts formula i . i . i agrees
with what is found in the Thecosomata, but BoAS and Pelseneer have clearly pointed out,
that this conformity in the number of teeth is quite accidental. Besides, the form of the teeth
(tig. 155) is quite different from that of the Thecosomata. The meclian tooth has no denticles;
each lateral tooth possesses a broad base and a slender point, which is türned upwards. There
are .sixteen or seventeen transverse series in the radula. — Immediately in front of it, the jaws
are situated, each of which consists of two or three rows of horny plates, the free margin of
which is saw-shapecl (fig. 156). The anterior plates are stronger than the posterior ones. The
jaws themselves unite neither dorsally nor ventrally. — Hook-sacs do not exist here. — Salivary
glands are the same as in all Gymnosomata and without real efferent duet. — The oesophagus
opens into the stomach at its left anterior corner; the structure of this stomach does not offer
special discussion. The intestine arises at the ventral side and runs straight on to the anus,
which lies beneath the posterior lobe of the foot, and nearly in the median line, though
somewhat to the right. Souleyet says that the intestine "décrit quelques infle.\ions autour de la
poche stomacale"; I have never seen this.

M uscula t ur e : In the reticulated connective tissue between the skin and the visceral
mass, three flattened muscle-bands attach this visceral niass to the body-wall. They are inserted
in the region of the neck, while distally they divide into several branches, which are strongly
attached to the skin. Two of the muscles are dorso-Iateral, one on each side of the body.
The third is ventral and median.

Generative organs: the gonad is situated posteriorly, and sometimes a little ventrally,
to the stomach. The efferent duet issues quite dorsally, then passes to the left and ventrally
(without exhibiting perceptible swellings in its course) and opens in the usual position, beneath
the distal margin of the right fin. As the stomach occupies the left portion of the visceral
mass, the genital duet is situated at the right side of the stomach ; it crosses the rectum at
its dorsal side. The accessory genital glands and the receptaculum seminis are situated in the
usual position, but I could not observe a separate muciparous and an albuminiparous gland.
The accessory genital glands have been already recorded and figured by Souleyet "). Speaking

i) Voyage de la Bonite, voL II, p. 246.

2) Voyage de la Bonite, vol. II, p. 24S, pi. XV, fig. 4.

87

about the digestive tract this aullior notes '), at the ris^ht side of the stomach, "uii corps dur
et jaunatre", the funclion of which he could not make out. Pelseneer ■) declared this hard
body to be the niuciparous gland. I too have foiind it in all specimens; in formol-preservation
it is opaque, whitish, while it becomes horny, transparent and brown in alcohol. I cannot,
however, regard it as a gland. For first it has never any connection with the genital duet
(as may be seen in transverse sections); and secondly it does not exhibit the structure of a gland
in any way, but is quite homogeneous, without showing cells or nuclei, and diffusedly absorbing
colouring matter. Perhaps it is a secretion of some gland which, however, is not yet known itself.

The penis, when invaginated, is club-shaped, and curved dorsally at its distal end. It
opens at the base of the right lateral lobe of the foot, as may be seen in transverse sections.

A most curious fact in Halopsyche is that this animal is ovoviviparous. This peculiarity
has been discovered already by M.'VCDonald ^) who found larvae in an advanced stage of
development. Xearly all the specimens of the Siboga enclosed larval stages in the connective
tissue beneath the skin. As the youngest stages were especially well represented, their study
is of the greatest importance. But I have thought it better to delay a full description of them,
as I intend to combine this study with other embryological researches on the Gymnosomata
at the Naples Station.

Although I took great care, I have not been able to recognize with certainty the
heart or the kidney. Not one specimen possessed an organ which could answer to a circulatory
or excretory apparatus. This fact is the more to be regretted, as neither Souleyet nor Pelseneer
have been more fortunate. Souleyet mentions a sac (the heart?) at the base of the so-called
"gills" (the buccal appendages), and Pelseneer notes some "very delicate organs" at the
right-side of the body.

I have found the central nervous system and the nerves issuing from it quite the same,
as Pelseneer described it. The visceral mass consists of three ganglia, while the pleural and
cerebral eanelia are fused toeether. There is onlv one nerve to the nuchal tentacle. The
cerebro-buccal connectives are remarkable for their shortness.

1) Op. s. c, p. 246, pi. XV, fig. 4, I, 9.

2) ChaU. Rep., LXVI, p. 53.

3) On the anatomy of Eurybia gaudichaudi, Transact. Linn. Soc. Lond., vol. XXII, p. 246, pi. XI, III, fig. 9. Some specimens
of the Challenger, which I examined in the Biltish Museum, were also provided with young larvae, a peculiarity which escaped the

notice of Pklseneer.

LIST OF THE SPECIES OF THECOSOMATA
AND GYMNOSOMATA IN THE AUSTRALASIAN WATERS

Species, maiked by an asterisk, have not been found by the Siboga.

A. THECOSOMATA.

I. LiMACINIDAE.

Limacina Cuvier.

Limaciiia inflata (d'Orbigny).
"Limacina lesueuri (d'Orbigny).
Limacina trochiformis (d'Orbigny).
Limacina bulimoides (d'Orbigny).

Peraclis Forbes.

Pcraclis reticulata (d'Orbigny) var. minor n. v.
Peraclis rissoides n. sp.
Peraclis moluccensis n. sp.

IL Cavoliniidae.

Clio Linné.

Subg. Creseis Rang.

Clio (Creseis) virgula (Rang).
Clio (Creseis) acicula (Rang).
'■[Clio (Creseis) chierchia Boas] ').

Subg. Hyalocylix Fol.
Clio (Hyalocylix) striata (Rang).

Subg. Styliola Lesueur.
Clio (Styliola) subuia (Ouoy et Gaimard)

Subg. Clio (s. str.] Linné.

Clio balantium (Rang).
Clio pyramidata Linné.
Clio cuspidata (Bosc).

Cavolinia Abildgaard.

Subg. Diacria Gray.

Cavolinia (Diacria) trispinosa (Lesueur).
Cavolinia (Diacria) quadridentata (Lesueur)

Subg. Cavolinia fs. str.) Pelseneer.

Cavolinia tridentata (Forskal).

Cavolinia uncinata (Rang).

Cavolinia gibbosa (Rang).

Cavolinia globulosa (Rang).

Cavolinia longirostris (Lesueur).

Cavolinia inflexa (Lesueur).

Cuvierina Boas.

Cuvierina columnella (Rang).

IIL CVlMEULlIDAE.

Cymbulia Peron et Lesueur.
Cymbulia sibogae n. sp.

Cymbuliopsis Pclseneer.

■■■'Cymbuliopsis ovata (Quoy et Gaimard).
Cymbuliopsis intermedia n. sp.

i) Reference is made to this species, on account of a statement by Boas (Spolia atlantica, p. 62) that one specimen was caught
at 137' E., 10° N. The occunence of this species in the Australasian province is tlierefore scarcely doubtful.

89

13. CrVMXOSOMATA.
I. Pneumünodhrmatidae.

Pneumonoderma Cuvier.

Pneiimonoderma peroni (Lamaick).
^Pneumonoderma mediterraneum (van Beneden).
Pneumonoderma heterocotylum n. sp.
Pneumonoderma pygmacum n. s]:>.

II. Clionopsid.\e.
Clionopsis (Troschel).

*Clionopsis grandis (Boas).
Clionopsis microcephalus n. sp.

III. NOTOBRANCHAEIDAE.
Notobranchaea Pelseneer.
Notobranchaea inopinata Pelsenecr.

lY. Clioniuae.
Clione Pallas.

Clione punctata n. sp.

Paraclione n. g.

Paraclione pelseneeri n. sp.

V. Halopsychidae.
Halopsyche Bronn.
Halopsyche gaudichaudi (Souleyet).

SIBOGA-EXPEDITIE LU.

APPENDIX.

When this work was being printed it appeared necessary to add some remarks :

I. During my stay at the Zoological Station at Naples I had an opportunity to get a look into
GioËNi's work, mentioned on p. 34. The author proposes on p. xxiv and p. xxv that the
animal, which without any doubt must be Cavolinia tridcntata, shall be called after him.
II. In August 1903 appeared a study by Pelseneer on the Mollusca of the Belgian Antarctic
Expedition (Résultats du Voyage du S. Y. Belgica, Mollusques par P. Pelseneer "Pteropoda",
p. 29 — 31). On p. 30 we find that the operculum of Liinaclna antarctica is coiled to the left.

III. In the Zool. Anz., Bd. XXVII, N" 10 and 11, Meisenheimer describes, after having studied
sufficiënt material, the anatomy of Desmopterits. A definite opinion with respect to the
systematic place the author does not give •, yet he seems inclined to think that Dcsinoptcrus
must be reckoned among the Gymnosomata.

IV. While printing this paper, I became acquainted with the very recently published study by
Kwietnewski, " Contribuzione alla conoscenza anatomo-zoologica degH pteropodi gimnosomi del
mare mediterraneo, Roma, 1903". Besides an extensive systematic and anatomical treatment
of the whole group, important information is given with respect to the Gymnosomata,
observed by the writer in the Strait of Messina. Some larval stages especially are of
importance and among these must be mentioned Thliptodon, which had not been found
ao-ain since Gegenbaur (1855). The author identifies Thliptodon with Pteroceanis Meisen-
heimer. To my inflnite regret I have not been able to take into account the results of
the paper above-mentioned, as my researches had come to an end already before.

LITERATURE SINCE 1885 ')•

1886. Pelseneer, P. Description d"iin nouveau genre de Ptéropode gymnosome, Bullet. Sci. Dép. Nord,
gme Ann. p. 224. Also: Ann. Mag. Nat. Hist. (5), vol. 19.

1887. Recherches sur Ie système nerveux des Ptéropodes, Arch. BioL, vol. VII.

Zool. Chall. Rep. LVIII (Gymnosomata).

1888. VuGï and YUXG, Lehrbuch der prakt, vergl. Anatomie, Bd. I, (Pteropoda: p. 828 — 852).
Pelseneer, P. Zool. Chall. Rep. LXV (Thecosomata).

Zool. Chall. Rep. LXVI (Anatomy of Pteropoda).

K.\LIDE, G. Beitrag z. Kenntniss der Musculatur der Heterop. u. Pterop., Zeitschr. f. wiss. Zool.,

Bd. 46, p. 337—377-
MUNTHE, H. Pteropoder i Upsala Univ. Zool. Mus., Bih. till Sv. Vet.-Ak. Handl., Bd. 13, Afd. IV, n" 2.

1889. Grobben, C. Zur Morphologie des Ptcropodenkörpers, Arb. Zool. Inst. Wien, Bd. VIII, p. 155 — 157.

Chun, C. Bericht ijber eine nach den canarischen Insein ausgefuhrte Reise, Sitz.-Ber. Berl. Ak., Bd.
III (Mollusca: p. 539 — 547).

Pelseneer, P. Sur la position systématique de Dcsinoplenis papilio Chun, Zool. Anz., Jahrg. XII,
p. 525—526.

Sur la valeur morphologique des sacs a crochets des 'Ptéropodes" gymnosomes. Zool. Anz.,

Jahrg. XII, p. 312—314.

Schalfejeff, P. Zur Anatomie der Clioue limacina Phipps, Zool. Anz., Jahrg. XII, p. 188 — 190.

Benoist, e. A. Description des Céphalopodes, Ptéropodes et Gastéropodes Opisthobranches, Act.
Soc. L. Bord., t. XLII.

SULIOTTI, A. G. Comunicazione Malacologiche, Bullet. Soc. Malac. Ital., t. XIV, p. 65 — 74.

Dall, W. H. On the genus Corolla, Naut. III, p. 30 — 32.

Preliminary catalogue of the shell-bearing marine Mollusca and Brachiopoda of the South-

Eastern coast of the United States, Bullet. U.S. Nat. Mus., n" 37 (Pteropoda: p. 80— 82, pi. LXVI).

WhiteleggE. List of the Invertebrate Fauna of Port Jackson and Neighbourhood, Proc. Roy. Soc.
New South Wales, vol. XXIII, p. 280 — 28 1.

1890. Peck, J. J. On the anatomy and histology of Cynibiiliopsis calceola, Stud. Biol. Lab. J. Hopk. Un.,

vol. IV, p. 334—353-

i) BOAS has given in his Spolia atlantica (p. 174 — 176) a complete list of the piincipal «oiks treating on "Pteiopoda", up
to the yeai' 1885.

92

iSqo. Smith, Edg. A. Report on the Marine Molluscan Fauna of the Islands of St.-Helena, Proc. Zool.
Soc. Lond., 1890. ("Pteropoda"': p. 254).

1891. Pelseneer, P. Sur la dextrorsité de certains Gastropodes dits "sénestres", Comptes rendus, t. CXII,

p. 1015 — 1017.
Knipowitsch, N. Zur Entwickelungsgesch. von Clione liuiacuia, Vorl. Mitth. in Biol. Centralbl.,

Bd. XI, p. 300 — 303,

. Sur Ie développement des Ptéropodes, Revue Sc. Nat. Pétersb., p. 177.

PiCTET, C. Recherches sur la spermatogenèse chez quelques invertebrés de la Méditerranée, Mitth.
Zool. Stat. Neapel, Bd. X. ("Pteropoda", viz. Cymbulia and Glcba: p. 115 — 122).

1892. Wackwitz, J. Beitrag zur Histol. d. MoUuskenfusses, spec. d. Pterop. u. Heterop., Zool. Beitr. A.

SCHNEIUER, Breslau, Bd. III, p. 129—160.

Brazier, J. Catalogue of the Marine Shells of Australia and Tasmania, Austral. Mus. Catal o" 15.
("Pteropoda": prt. II).

1893. Peck, J. J. Report on the (Thecosomatous) Pteropoda and Heteropoda, etc, Proc. U. S. Nat. Mus.,

vol. XVI, p. 451 — 466.

1894. Pelseneer, P. Hermaphroditism in Mollusca, Ouarterl. Journ. Mier. Sci. vol. XXXVII, p. 19 — 46.

Recherches sur divers Opisthobranches, Mem. cour. Sav. Etrang. Ac. Brux., t. 53.

Knorver, H. Mc. E. Pteropods with two separate sexual openings, J. Hopk. Un. Circ, vol. XIII.
p. 61—62. (Also: Ann. Mag. Nat. Hist. (6), vol. XIII, p. 529—530).

Kleinenberg, N. Sullo sviluppo del sistema nervoso peripherico, etc, Monit. Z. Ital., Anno 5, p. 75.

1895. Hornell, J. Anatomical description of Crcseis as a typical Pteropod, Marine Zool., vol. II, p. 19 — 24.

1897. LOCARD, A. Expéditions scientifiques du Travailleur et du Talisman, Mollusques testacés. ("Pteropoda":

vol. I, p. 5— 31)-

1898. M'Intosh. On some larvae stages of Clione Uuiaciiia Phipps, Ann. Mag. Nat. Hist. (7), vol. II,

p. 103—105.

Oberwimmer, A. Zool. Ergebn. X, ges. v. S. M. Schift" "Pola", Denkschr. Kais. Ak. Wiss. Wien.
Bd. LXV, p. 573—595-

1900. Carazzi, D. Le prime fasi dello sviluppo del Pncumodcnna incditcrrancuut van Beneden, Anat.

Anz., Bd. XVII, p. 102.

1901. HEATH & Spaulding. CynibuUopsis vitrca, a new species of Pteropod, Proc. Ac. Philad., 1901

p. 509—511.

1902. Meisenheimer, J. Über eine neue Familie der gymnosomen Ptcropoden, etc. Zool. Anz., Jahrg.

XXVI, p. 92—99.

1^03. Über ein neues Genus der gymnosomen Pteropoden, etc. Zool. Anz., Jahrg. XXVI, p. 410 — 412.

EXPLANATION OF PLATES

PLATE I.

Fig. I. Operculum Liinacina inflata d'Orb., froni the outside.

Fig. 2. Stomach Liniacina helicina Phipps, veiitral view. (;, oesophagus; /;, beginning of the intestine;

c, coecum.
Fig. 3. Central nervous system Liinacina lieUcina Phipps, A, ventral view. B, from the left side. C, from

the right side.
p and /', left and right pedal ganglion; v and v , left and right visceral ganglion; c and c', left

and right cerebral ganglion; i and i', nerves to the fins; 2, left pallial nerve; 3, right pallial

nerve; 4 and 5, visceral nerves; 6 — 9, nerves to the tentacles and to the lips; 10, cerebral

commissure; ot and oi , left and right otocyst.
Fig. 4. Shell Pcraclis reticulata var. minor. 36 <.
Fig. 5. Shell Peraclis rissoides n. sp. 33 ,•'.
Fig. 6. Operculum of the same, from the outside.
Fig. 7. Shell Pcraclis iiiolucceiisis n. sp. 25 x.
Fig. 8. The same, seen from apex. 20 >'.
Fig. 9. Fragment of the same, seen from apex. 60 X.
Fig. 10. Operculum of the same, seen from the outside.
Fig. II. Head Pcraclis rissoides n. sp. Dorsal view.
Fig. 12. Jaw Peraclis reticulata var. minor, 2"Q ser. of right jaw.
Fig. 13. Pallial gland Pcraclis rissoides n. sp., from the outside. a, "balancer".
Fig. 14. Central nervous system Pcraclis rissoides n. sp. A ventral view. B, from the right side.

Explanation of letters the same as in fig. 3. Besides, /. v., posterior visceral ganglion.
Fig. 15. Shell '^ Agadina" n. sp. A, from aperture. B, from umbilicus. 22 - .
Fig. 16. Shell (probably abnormal) of Clio (Hyalocylix) striata (Rang). Ventral view. 10 X.
Fig. 17. Embryonic shell of Clio (Hyalocylix) striata (Rang).

Fig. 18. Intestine Clio cuspidata. a, intestine; b, glandular organ, attached to it.
Fig. 19. Accessory genital glands Clio (Crescis) acicula (Rang), from the left side. a, efferent duet of the

gonad; b, accessory genital gland; c, vas deferens (" Vagina" Gegenbaur); cl, receptaculum seminis (?).
Fig. 20. Genital organs Clio (Styliola) subuia (Quoy et Gaimard). Dorsal view.
Explanation of letters the same as in fig. 19. g, gonad.

Sibnpa-Expcditic. Lil. J. .1. Tksch, Thocosoraata. and Gymnosomata.

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PLATE IL

Fig.

!I.

Fig. 22.

Fig. 23.
Fig. 24.
Fig. 25.

Fig. 26.

Fis

Fig.

32

Fig.

33

Fig.

34

Fig.

35

Fig.

36

Fig.

45

Fig.

54

Fig. 59—6

^ 'S-

u/f.

Fig.

65.

Fig.

66.

Fig.

6j.

Fig.

68.

Fig.

69.

Fig.

70.

Fig.

71-

Fig.

72.

Fig.

73-

Fig.

74-

Fig.

75-

Fig.

76.

Fig.

77-

Fig.

78.

Fig. 79.

Central nervous system Clio (Crescis) acicula (Rang). Ventral view.

/ and /', left and right pedal ganglion; v and v' , left and right visceral ganglion; i and i',

nerves to the fins; 2, left pallial nerve; 3, right pallial nerve; 4 and 5, visceral nerves; et

and ot' , left and right otocyst.
Central nervous system Clio pyrauiidata (Linn.). Ventral view.
Explanation of letters the same as in fig. 21. Besides, 6, tentacular nerve.
Buccal ganglia Clio pyraniidata (Linn.), fused together as in all Cavoliniidae.
Cervical organ Cuvierina coluinnella (Rang), from the right side.
Genital organs of the same, dorsal view. g, gonad; a, its efferent duet; /;, accessory genital

glands ; c, vas deferens.
Central nervous system of the same. A, ventral view. B, from the left side.
p, pedal ganglion; %', visceral ganglion; c, cerebral ganglion; a, anterior pedal commissure.

I and 2, nerves to the fins; 3, left pallial nerve; 4, right pallial nerve; 5 and 6, visceral

nerves; 7, a nerve perhaps supplying the cervical organ; 8 and 9, nerves to the tentacles

and to the lips; ot, otocyst.
31. Difierent shells of Cavoliiiia (Diacria) trispinosa (Les.). 2 X-

^Hyalaea affinis", a variety of Cavolinia tridentata (Forskal); dorsal view. 2 X.
The same, seen from the left. 2 • .

Probably anomalous shell of Cavolinia gibhosa (Rang). 2 X.
The same, seen from the left. 2 ;■; .
44. Series of shells of '^ Plcuropiis longifilis" Troschel, to show the transition to the adult Cavolinia

tridentata (Forsk.). Seen from the right. 2 X-
53. Series of the same specimens, dorsal view. 2 y.
58. Series of shells of Cavolinia inflexa (Les.), transition from the variety lata to longa. Dorsal

view. 2 >; .
Series of the same specimens, seen from the left. 2 /,. The specimens i and 4 in these

series were caught by the Siboga, the other specimens are from the Atlantic.
Shell and animal of "'Cleodora coniprcssa" Souleyet. Ventral view. 10 • .
Shell of " Clcodora pygmaea" Boas.

Shell of '^ Pleuropus longifilis" Troschel, from Naples. Dorsal view. 10 X.
Same specimen, seen from the right. 10 '•■■'.

Shell and animal of '^ Fleuropns longifilis" Troschel. (Siboga-specimen). Dorsal view. 10 X.
Same specimen, seen from the left. lo • .
Shell of '^ Hyalaea rotundatd' . Dorsal view. lo X.
The same specimen, seen from the right. 10 X.
Shell of ^Hyalaea Icvigata" . Dorsal view. 10 X.
Same specimen, from the right. 10 •'.
Shell of "Hyalaea depressa". Dorsal view. 10 x.
Same specimen, from the right. Nearly adult; the shell is already very much likc that of

Cavolinia inflexa.
Shell of '^Hyalaea depressa". Dorsal view. 10 :• . A younger stage than the foregoing one.
Same specimen, from the right. 10 .

Central nervous system of Cavolinia tridentata. Ventral view.
p, pedal ganglion; v, visceral ganglion; i, nerve to the fins; 4, left pallial nerve; 3, right

pallial nerve; 2 and 5, visceral nerves; ot, otocyst.
Central nervous system of the same, seen from the left.
E.xplanation of letters the same as in fig. 78. Besides, e, cerebral ganglion; 6, tentacular nerve.

Sibogn -Expeditie. LIL ,T. J. Tesch, Thecosomata and Oymnosomata.

//.

J. J. Tesch, del.

P. J. Mulder, Impr.

PLATE IIL

Fig. 80. '^ Desmoptcrits' sp. Aboral view. 10 X.

Fig. 81. Same specimen. Oral view. 10 x.

Fig. 82. Cyinbulia peroni de Blainv. from Naples. Large specimen. Oral view. 2 X.

Fi". 83. Empty shell of the same specimen, from the right. a, b, c, three rows of spines; the first of these

rows only reaches the ventral point. Some spines at the aperture are very large. 2 X.
Fig. 84. Same shell, aboral view. 2 ■ .

Fig. 85. Another specimen of Cyinbulia peroni de Blainv., from the same locality. 2 X.
FiCT. 86. Empty shell of the same specimen, from the right. The row a only exists. 2 X. Spines at the

aperture of equal size.
Fig. 87. Same shell, aboral view. 2 • .
Fig. 88. Cyinbulia sibogae n. sp. Oral view. 2 X-
Fig. 89. Same specimen, from the right. 2 X.
Fig. go. Same specimen, aboral view. 2 /. d, a row of spines, which (according to Pelseneer's figure at

least) does not reach the middle of the shell in Cyinbulia parvidcntata.
Fig. 91 — 93. Three specimens of Cyinbulia, without shell. See text. Figs. 91, 93: 2 v'. Fig. 92: 5 X.
Fig. 94. Pallial gland of Cyinbulia peroni de Blainv. Aboral view. d, v, dorsal, ventral margin, a, b, first

and second transparent band.
Fig. 95. Dorsal view of the accessory genital glands of Cyinbulia peroni de Blainv. a, efferent duet of the

gonad; b, muciparous gland; c, albuminiparous gland; d, receptaculum seminis; /, vas deferens.
Fig. 96. Central nervous system of Cyinbulia peroni de Blainv., ventral view.

a, anterior pedal commissure; p, pedal ganglion; v, left visceral ganglion; p.v., posterior visceral

ganglion; i, nerves to the fins; 2, left pallial nerve; 3, right pallial nerve; 4 and 5, visceral

nerves; ot, otocyst.
Fig. 97. The same, from the left. Explanation of letters the same as in the foregoing figure. Besides,

c, cerebral ganglion ; 6, tentacular nerve, 7 and 8, nerves to the proboscis.
Fig. 98. The same, oral view. Explanation of letters the same as in figs. 96 and 97. Besides, 9 and 10,

pedal nerves, perhaps supplying the retractor muscle of the proboscis. Nerves to the fins are

not figured.
Fig. 99. Distribution of the nerves in the fins of Cyinbulia peroni de Blainv.

Siboga- Expeditie. LIL .T. .1. Tksch, Theiosomata and Gymnosoniata.

///.

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92.

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P. J. Mulder, Impr.

PLATE IV.

Fig. lOO. Cy)nlutliopsïs internicdia n. sp., oral view. 2 ■.

Fig. lOi. Empty shell of the same species, oral (anterior) view. 2 •.

Fig. 102. Same shell, (aboral) posterior view. 2 • .

Fio-. 103. Another empty shell, most probably belonging to the same species. Anterior view. 2 X.

Fig. 104. Same shel!, posterior view. 2 ■ .

Fig. 105. A specimen of CymbuUopsis without shell, anterior view. 2 ^■.

Fig. 106 — 108. Larval Cymbulidae, perhaps belonging to different species. In fig. 106 the penis is evaginated.

Fig. 109. Gleba cordata Forskal from Naples. Anterior view. 2 X.

Fig. iio. Large shell of the same, posterior view. 2 •.

Fio-. III. Pallial gland of CymbuUopsis inter media n. sp., from the outside. a, b, c, three transverse,

transparent bands.
Fig. 112. Pallial gland of GU-ba cordata Forskal, from the outside. a, b, c, have the same meaning as

in fig. III.
Fig. 113. Digestive tract of CymbuUopsis intermedia n. sp. Ventral view. oe, oesophagus; v, stomach ;

/, intestine ; a, anus.
Fig. 114. Heart and kidney of GMm cordata Forskal, ventral view.

a, ventricle of the heart; ao, and ao.,_, two vessels issuing from it; b, kidney; c, mantle-cavity ;

d, opening of the kidney into the mantle-cavity; c, opening of the mantle to the exterior;

pc, pericard.
Fig. 115. Central nervous system of Cymbuliopsis intermedia n. sp., from the right side.

a, cerebral commissure; c, cerebral ganglion; /, pedal ganglion; v, right visceral ganglion; pv.,

posterior visceral ganglion; i, nerve to the tentacle; 2, nerve to the penis; 3, nerve to the

proboscis, innervating its retractor muscle; 4 and 5, nerves to the fins; 6, pallial nerve;

7, visceral nerve; ot, otocyst.
Fig. 1 16. Central nervous system of Glcba cordata Forskal, from the right. Explanation of letters the same

as in fig. 115,
Fig. 117. Distribution of the nerves in the fins of Gleba cordata Forskal.

Sibogn-Expeditie. LIL J. J. Tescii. TheL-usoiuala ;ukI (lymuusuiuala.

IV.

101.

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V^:

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105.

117.

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107.

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113.

114

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J. J. Tcseh, del.

I'. J. Jlulder, Impi.

PLATE V.

Fig. II 8. PnciunonodcrDia licterocotyluin n. sp. Ventral view. 6 X.

Fig. \\%A. Lateral gill of the same.

Fig. iiSB. Posterior gill of the same, dorsai view.

Fig. 119. Acetabuliferous appendage of the same; out-stietched, from the inside.

Fig. 120. Pncuiiionodenna pygiiiacuui n. sp. Ventral view. 10 X.

Fig. 121. Posterior gill of the same, aboral view. d, dorsai; z', ventral.

Fig. 122. Acetabuliferous appendage of the same; out-stretched, from the inside.

Fig. 123. Some larval Pnciiuionodcnna, ventral view. 10 • . Strongly contracted.

Fig. 124. Central nervous system oi Pncuuionodentia nieditcrrancuin (van Ben.). Dorsai view. — Pedal nerves

and cerebro-buccal connectives not figured.
c, cerebral ganglion; a, cerebro-pedal connective; b, cerebro-pleural connective; p, pedal ganglion;

pi, pleural ganglion; plv, pleuro-visceral connective; v, visceral ganglion.
I, optie nerve; 2, olfactory nerve; 3, auditory nerve, turned to the front; 4, nerve to the labial

tentacle; 5 — 7, nerves to the proboscis, the lips and the buccal appendages; 13, 14, pleural

nerves to the cervical region ; 15 — 17, nerves to the envelop of the visceral mass; iS — 19,

nerves to the viscera.
Fig. 125. Pedal ganglia of the same. Dorsai view.

ap, anterior pedal commissure; /, pedal ganglion; a, cerebro-pedal connective, ot, otocyst.

8, nerve to the foot; 11 — 12, anastomosing nerves to the fins; 9 — 10, anastomosing nerves, the

function of which remained unkiiown to me.
Fig. 126. Clioiiopsis niicroceplialiis n. sp. Ventral view. 4 X.
Fig. 127. The same, from the left. 4 X.
Fig. 128. Radula of the same.

Fig. 129. Notobranchaea inopinata Pels. Ventral view. 10 X.
Fig. 130. The same specimen. Dorsai view. 10 ■.
Fig. 131. Head of the same, dorsai view. bc, buccal cones.

Fig. 132. Oral aspect of the head ; cephalic hood nearly closed. //, labial tentacle.
Fig. 133. Foot of the same; /, tubercle.
Fig. 134. Dorsai crest of the gill of the same.
Fig. 135. Radula of the same.

Sibnga-Expeditic. LIL J. J. Tescii, Thecosomata and (iymiiüsomata.

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PLATE VI.

Fig. 136. Notobrancliaea sp. Larva. Ventral view. 30 .

Fig. 137. The same, dorsal view. 30 .

Fig. 138. Dorsal view of the aboral extremity of the same, showing the cutaneous glands, and the two
cihated rings.

Fig. 139. Transverse section through one of the "Mundblasen" of Notobrancliaea inopinata Pels.

a, a layer of epithelial cells with flat nuclei, at the periphery; b, layer of glandular cells,
immediately beneath a, with piolongations into c, a reticulated net-work of conncctive tissue

Fig. 140. Genital organs of Notobrancliaea inopinata Pels. Ventral view. g, gonad; d, its duet; a, muci-
parous, b, albuminiparous gland; v, vas deferens.

Fig. 141. Penis of the same, invaginated. See text.

Fig. 142. Clione pnnctata n. sp., ventral view. 15 X.

Fig. 143. Chromatophors of the same.

Fig. 144. Central nervous system of Clionc lunacina Phipps. Dorsal view. c, cerebral ganglion; bc, cerebro-
buccal connective; pc, cerebro-pedal connective; plc, cerebro-pleural conncctive; plv, pleuro-
visceral connective; /, pedal ganglion;/"/, pleural ganglion; v, visceral ganglion; i, olfactory
nerve; 2, optie nerve; 3, auditory nerve; 4, nerve to the ventral bueeal eone; 5, nerve to
the labial tentaele ; 6, nerve to the dorsal, 7, to the middle cone; 11, pedal nerve, forming
a plexus with 12, pleural nerve, to the eervical region; 14, 15, 16, nerves from the visceral ganglia.

Fig. 145. Basal part of the optie nerve, with the two elongated swellings.

Fig. 146. Pedal ganglia of the same. Dorsal view. For the completion of fig. 144. pc, cerebro-pedal
connective; apdc, anterior pedal commissure; pede, posterior pedal commissure; 8 and 10,
nerves to the lobes of the foot; 9, nerves to the fins; 13, nerve from the ventral surfaee of
the pedal ganglion.

Fig. 147. Paracliojie pelseneeri n. sp. Ventral view. 20 • .

Fig. 148. Another specimen of the same species. Same view. 30 X.

Fig. 149. A third specimen. Same view. 15 ■.

Fig. 150. A fourth specimen. Same view. 20 X-

Fig. 151^^. Radula o{ Paraclione pelseneeri n. sp.

Fig. I5ii>. Hooks of the same.

Fig. 152. Oral aspect of the head of the same.

d, dorsal; v, ventral; b, bueeal eone; /, labial tentaele; c, cephalic hood ; f, false lips; r, radula.

Fig- 153- Head and bueeal appendages of Halopsyclie gaudichaudi (Souleyet). Ventral view.

ba, bueeal appendage; //, labial tentaele; al, anterior lobes of the foot; o, mouth; nt, nuchal
tentaele; /, fin; //, posterior lobe of the foot.

Fig. 154. Transverse section through the skin of the same. a, skin, properly so ealled, b, reticulated
tissue, between the skin and the visceral nucleus; i, pavement epithelium; 2, 3, 4, several
forms of dermal glands. See text.

Fig. 155. Radula of the same.

Fig. 1^6 A, B, C. Horny plates of the jaws of the same.

Siboga-Expeditie. LIL J. J. Tesch Thecosomata and Gymnosomata.

VI.

13(i. "

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151.

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RÈSULTATS DES EXPLORATIONS
ZOOLOGIQUES, BOTANIQUES, OCÈANOGRAPHIQUES ET GÉOLOGIQUES

KNTUEPKISKS AUX
rUDES NÉERI.ANDATSF.3 ORtENTAI.ES on 1899 — 1900,

a

bord du iSIlBOa-.^

sous I.K COMMANDF.MENT DE

G-. F. TYDEMAN

PUBLIÉS PAK

MAX TVKBKR,

Chet do l'expédition.

*I. lutroduction et dcscriptioa de rexpéditiou, Max Webér.
*II. Le bateau et son équipement scieutifique, G. F. Tydeman
«III. Re'siiltats hydrographiques, G. F. Tydeman.
IV. Foraiiiinifera.
V. Radiolaria, M. Hartmann.
•VI. Poiifera, G. C. J. Vosmaer et J. H. Vernhout ').
VII. Hydropolypi, Ch. Julin.
VIII. Hydrocoralliuae, S. J. Hickson.
IX. Siplionophora, JlHes Lens et van Riemsdijk.
X. Hydi-omedusae, O. Maas.
*XI. Scvphoiuedusae, O Maas.
»XII. Ctènophora, MUe F. Moser.
*XIII. Gorgouidae, Alcyonidae, J. Versluys ').
XIV. Pennatulidae, S. J. Hickson.
XV. Actiniaria, P. Mc Murrich.
*.XVI. Madvepoiaria, A. Alcock ') et L. Uöderlein.
XVII. Autipatharia, P. N. van Kampen.
XVIII. Turbellaria, L. von Graff et R. R. von Stumraer.
XIX. Cestodes, J. W. Speiigel.
XX. Nematodes, A. A. W. Hub recht.
XXI. Chaetojnatha, G. H. Fowler.
XXII. Nemertini, A. A. W. Kubrecht.
XXIII. Myzostoraidae, R. R. von Stumraer.
XXI Va. Polychaeta errantia, R. Horst.

XXIVA. PolVchaeta sedeutaria, M. Caullery et F. Mesuil.
»XXV. Gepbyrea, C. Ph. Sluiter.
X.WI. Entei-opueusta, J. W. S pen gel.
XXVn. Bvachiopoda, J. F. van Bemmelen.
XXVIII. Brvozoa, S. F. Harmer.
XXIX. Copepoda, A. Scott.
XXX. Ostracoda, G. W. Muller.
XXXI. Cirrhipedia, P. P. C. Hoek.
XXXIIa. Isopoda, H. J. Hauseu.
XX.XIIi. Epicaridae, J. Bonn ie r.
XXXIIl. Amphipoda, J. Bonnier.
«XXXIV. Caprellidae, P. May er.
XXXV. Stomatopoda, H. J. Hansen.
XXXVI. Cumacea, W. T. Cal man.
XXXVII. Schizopoda, H. J. Hanseu.
XXXVIII. Sergestidae, H. J. Hansen.
XXXIX. Decapoda, J. G. de Man.
XL. Pautopoda, J. C. C. Lomau.
XLI. Halobatidae, J. Th. Oudenians.
XLII. Crinoidea, L. Döderlein p. p.
«XLIII. Echinoidea, J. C. H. de Meijere.
».XLIV. Holothurioidea, C. Ph. Sluiter.
«XLV. Ophiuroidea, R. Kohier').
XLVI. Asteroidea, L. Döderlein.
»XLVII. Solenogastres, H. F. Nierstrasz.
XLVIH. Chitonidae, H. F. Nierstrasz.
XLIX. Prosobranchia, M. M. Schep man.
L. Opisthobranchia, R. Bergh.
LI. Heteropoda, J. J. Tesch.
*LII. Pteropoda, J. J. Tesch.

LIII. Lamellibraachiata. P. Pelseneer et Ph. Dantzenberg.
LIV. Scaphopoda, Mi'e M. Boissevain.
LV. Cephalopoda, L. Joubin.
LVI. Tunicata, C. Ph. Sluiter.
LVII. Pisces, Max Web er.
LVni. Cetacea, Max Weber.
LIX. Liste des al?ues, Mme A. Weber.
*LX. Halimeda, MUe E. S. Barton. (Mme E. S. Gepp).
LXI. Corallinaceae, Mme A. Weber et M. F os He.
LXir. Dinoflagellata. Coccosphaeridae, J. P. Lotsy.
LXIII. Diatomaceae, J. P. Lotsy.
LXIV. Deposita marina, O. B. Böggild.
LXV, Résultats géologiques, A. Wichtuann.

Siboga-Expeditie

THE THECOSOIATA AND GIINOSOÏATA
OF THE SIBÖGA-EÏPEDITION

BY

J. J. TESCH

Utrecht
With six plates

Monographie Lil of:

UITKOMSTEN OP ZOOLOGISCH,
BOTANISCH, OCEANOGRAPHISCH EN GEOLOGISCH GEBIED

verzameld in Nederlandsch Oost-In die 1899 — i

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

UITGEGEVEN DOOR

Dr. MAX WEBER

Prof. in .\nisterd.im, Leider der Expeditie

900

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

-:=r^O<s-?<-=:i~-

BOEKHANDEL EN DRUKKERIJ
E. J. BRILL

LEIDEN

1,^^^^^^^

:^3 ^.O C/[\j Crl,

"j ÖjD'a^v; 1

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V ^y ^yO^v

i^rï^C ölct/jöi

Publié Avril 1904

' Les numéros avec un astérique ont déja paru; ceux marqués i) seulement en partie.

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

De Maatschappij ter bevordering van het Natuurkundig Onderzoek der Nederlandsche
Koloniën.

Het Ministerie van Koloniën.

Het Ministerie van Binnenlandsche Zaken.

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

De »Oostersche Handel en Reederij" te Amsterdam.

De Heer B. H de Wa.\l Oud-Consul-Generaal der Nederlanden te Kaapstad. .

CONDITIONS GÉNÉRALES DE VENTE.

i^. L'ouvragc du „Siboga" se coniposcra d'une série de monographies.

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

3°. Le prix de chaque monographie sera différent, mais nous avons adopté comme base générale du prix de
vente: pour une feuille d'impression sans fig. flor. 0.15; pour une feuille avec fig. flor. 0.20 a O.25 ;
pour une planche noire flor. 0.25; pour une planche coloriée flor. 0.40 ; pour une photogravure flor. 0.60.

4°. I) y aura deux modes de souscription :
a. La souscription a l'ouvrage complet.

è. La souscription a des monographies séparées en nombre restreint.
Dans ce dernier cas, le prix des monographies sera majoré de 25 "j^.

5°. L'ouvrage sera réuni en volumes avec titres et index. Les souscripteurs a l'ouvrage complet recevront
ces titres et index, au fur et a mesure, que chaque volume sera complet.

Déja paru:

ie Liviaison. (Monographie XLIV) C. Ph. Sluiter. Die Holothuiien der Siboga-Expedition. Mit loTafeln.

/7-5o
Pour les soiiscripteurs a Vonvrage complet. „ 6. —

2e Livraison. (Monographie LX) K. S. Barton. The genus Halimeda. With 4 plates . . . . / 2.40

Poio' les soiiscripteurs a rouvrage complet. „ 1.80

3e Livraison. (Monographie I) MaX Weber. Introduction et description de 1'expédition. Avec Liste des

Stations et 2 Cartes ƒ 9. —

Pour les souscripteurs a rouvrage complet. „ 6.75

4e Livraison. (Monographie II) G. F. Tydeman. Description of the ship and appliances used for scientific

exploration. With 3 plates and illustrations ƒ 2.50

Pour les souscripteurs a Fouvrage complet. , 2. —

5e Livraison. (Monographie XLVII) H. F. Nierstrasz. The Solenogastres of the Siboga-Expedition. With

six plates ƒ 4.90

Pour les souscripteurs h Fouvrage complet. „ 3.90

6e Livraison. (Monographie XIII) J. Versluys. Die Gorgoniden der Siboga-Expedition.

I. Die Chrysogorgiidae / 3.75

Pour les souscripteurs a Fouvrage complet. „ 3. —

7e Livraison. (Monographie XVI 0:) A. AlcOCk. Report on the Deep-Sea Madreporaria of the Siboga-
Expedition. With five plates f 5.75

Pour les souscripteurs a Fouvrage complet. „ 4.60

8e Livraison. (Monographie XXV) C. Ph. Sluiter. Die Sipunculiden und Echiuriden der Siboga-Expedition.

Mit vier Tafeln und drei Figuren im Text / 3-75

. Pour les souscripteurs a Fouvrage complet. „ 3. —

9e Livraison. (Monographie VI) G. C. J. Vosmaer and J. H. Verilhout. The Porifera of the Siboga-
Expedition. With five plates ƒ 3. —

Pour les souscripteurs a Fouvrage complet. „ 2.40

loe Livraison. (Monographie XI) Otto Maas. Die Scyphomedusen der Siboga-Expedition. Mit XII Tafeln.

/9-50
Pour les souscripteurs a Fouvrage complet. „ 7.50

iie Livraison. (Monographie XII) Fanny Moser. Die Ctenophoren der Siboga-Expedition. Mit 4 Tafeln.

/ 3-50
Pour les souscripteurs a Fouvrage complet. „ 2.80

12e Livraison. (Monographie XXXIV) P. Mayer. Die Caprellidae der Siboga-Expedition. Mit 10 Tafeln.

f 9-7S
Pour les souscripteurs Ir Fouvrage complet. „ 7.80

13e Livraison. (Monographie III) G. F. Tydeman. Hydrographic results of the Siboga-Expedition. With

24 charts and plans and 3 charts of depths ƒ 11.25

Pour les souscripteurs a Fouvrage complet. „ 9. —

14e Livraison. (Monographie XLIII) J. C. H. de Meijere. Die Echinoidea der Siboga-Expedition. Mit

23 Tafeln ƒ 18.75

Pour les souscripteurs a Fouvrage complet. „ 1 5 . —

15e Livraison. (Monographie XLV) René Koehler. Ophiures de l'Expédition du Siboga.

ie Partie. Ophiures de Mer profonde. Avec 36 Planches f 20.50

Pour les souscripteurs a Fouvrage complet. „ 16.50

StE.-

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