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VERZAMELD IX

NEDERLAXDSCH OOST-INDIÊ 1899— 1900

AAN BOORD H. M. SIBOGA ONDER COMMANDO VAN

Luitenanl ter zee 1 kl. G. F. TYDEMAN

ÜITI iEGEVEN DOOR

Dr. MAX WEBER

Prof. in Amsterdam., I.ei»ier der Expeditie

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

BOEKHANDEL EN DRUKKERIJ

E. J. BRIJL.L
LEID! N

Sib o ga- Expeditie

XXXIa

THE

CIRRIPEDIA OF THE SIBOGA EXPEDITION

BY

P. P. C HOEK

A. CIRRIPEDIA PEDUNCULATA

With 10 plates

late E J. BRILL

PUBLISHERS AND PRINTERS

LEIDEN — I907

A. CIRRIPEDIA PEDUNCULATA

Genus Lepas Linnaeus

Of the species forming this genus six were already known to Darwin1 (185 1) and two
only have been added since the appearance of the "Monograph": one (Lepas testudinata) by
Aurivillius - in 1892 and one (Lepas denticulata) by Gruvel3 in 1901.

Most of the species of this genus have "enormous ranges", as Darwin (1. c.) remarked,
yet the number of species hitherto observed with certainty in the East Indian Archipelago
amounts to only four, viz.

Lepas anatifera Linn. Philippine Archipelago, according to Darwin.

Lepas anserifera Linn. East Indian Archipelago (Darwin); Java Sea, Moluccan SeaCChallenger");

Sumatra, Ambon, Ternate etc. (Weltner).
Lepas fascicularis Ellis & Solander. East Indian Archipelago, off Borneo and Celebes (Darwin).
Lepas denticulata A. Gruvel. Honda Bay (Philippines).

{Lepas Hilli (Leach) which was collected by A. Menzies in the "South Seas" and
was found at Port Stephen, Australia (Darwin), Lepas pectinata Spengler, which, according to
Darwin, is common under the tropics and Lepas australis Darwin, which Darwin believed to
be confmed to the Southern Ocean, have not hitherto been observed in the East Indian
Archipelago ; nor has Lepas testudinata Aurivillius, known only from the neighbourhood of the
Cape of Good Hope).

All the species of this genus live attached to floating objects and therefore seem to be
inhabitants only of the surface-layers of the sea.

The specimens of the genus Lepas collected by H. M. S. "Siboga" belong to two species
only : L. anserifera Linn. and L. fascicularis Ellis and Solander.

1 Darwin, C, A monogvaph of the sub-class Cirripedia. The Lepadidae or Pedunculated Cirripedes. London, 1851.

2 Aurivillius, C. W., Neue Cirripeden aus dem Atlantischen, Indischen und Stillen Ocean. Öfversigt af K. Svensk. Vet.
Akad. Förli. 1892, N° 3.

3 Gruvel, A., Étude d'une espèce nouvelle de Lépadides. Trans. Linn. Soc. (2), VIII, 5, 1901.

SIEOGA-EXPEDITIE XXXI a.

.^478,

i. Linn.

This seems to be by far the commonest species in the part of the tropics explored bj
11 M s 'Siboga '. 11 was not only collected at numerous places during the cruise, ii was also
■ ral times found attached to the ^liip itself after being cleaned in th<: doek of Surabaja.

Th<- places and stations where the species was taken are

• Labuan Tring Lombok), March 20, 1899. I in ■• specimens attai

tn .1 • ■ wood. Surface. Anoth 1 smaller specimens with a barb

na attached to a piece <>!" pumice-stone.

Bril" iu.ii Macassar. No date. Very small specimens attached t<i Spirula, the
largi imen nas .1 capitulum <>f 6 mm. They belong t" the var. dilatata:

scuta broad, carina barbed.

110. July '. 1899. Lat. 4 }4 X.. I ' E.; South of Sulu Archipelago. Surface.

Two specimens; length of the capitulum of the larger, 25 mm.

;. Daram Island (East Coast of Misool), August 22, [899. Attached to a piece of
:. Small specimens <>f 6 mm. and smaller: var. dilatata. Associated with
L. fascicularis Ellis & Solander.

Buton Strait, September 21, 1899. Surface. between Algae. Very small specimens attached t'>
rula. Var. dilatata with barbed carina.

Stat. 214. October 27, 1899. Lat. 6° 30 X.. L<>ng. 1 2 1 ° 3 5 1". Surface, attached to Spirula.

Very small specimens: var. dilatata.
Stat. 228. November 14. [899. Lat. 4 ^o S„ Long. 128° 30'. 5 K. Surface. Small speen

attached to a species of Fuci. [The largest specimen lias a capitulum "f7.5 mm.].
No place, no date. Attached to the keel of II. M. S. "Siboga". One specimen. Length of the

capitulum 20 mm.
July 10. d t<> the keel of II. M. S. "Siboga", 4') days after having been docked

in Surabaja. Si/e of largest specimen: capitulum 21 mm. The larger individuals

are furnished with ovigerOUS lamellae.
• bcr 15. \ttached to the keel of H. M. S. "Siboga", 107 days after the ship was

cleaned in the doek of Surabaja. Several specimens: length of the capitulum of

the individual, 25 mm.

Rein ark s. The specimens collected in the Bay of Lal man Tring (Lombok) caused me

some dimculty as they differed from the usual appearance of L. anserifera in one of its most

distinctive characters, viz. in the occludent margin of the scutum not being arched or protuberant.

Further, the internal umbonal tooth of the right-hand scutum in these specimens is hardly stronger

than that of the left-hand scutum. But as these characters vary even within the specimens ol

this locality, the form of the scutum in some of them approaching more to the typical form

than is the case in others; there existing, moreover, a close resemblance in other regards between

this and the typical form, no doubt was left as to the importance of this difference. Several

from this locality show the straight line of small quadritateral depressions ol a dirty

ir in the scutum, running diagonally across the capitulum, which are very common

in / Darwin 1. c. p. 7 erved a tracé of a diagonal line of such marks in a

of /.. Hilli — but they have not been observed before in /.. anserifera, so

3
2. Lepas fascicularis Ellis & Solander.

This species which is rather common in tropical seas was observed once only during
the cruise of die "Siboga", viz. on Aug. 22, 1899 (Station 165), anchorage on north-east side
of Daram Island (False Pisangs), East Coast of Misool.

There are medium-sized and small specimens ; the larger ones have the capitulum
20 mm. long.

The valves stand at a certain distance from each other and have very distinctly brown-
coloured margins. The shape of the carina nearly approaches that of the typical form ; the
lower part however does not expand in such a broad disc as figured by Darwin.

Some of the specimens are attached to fuci associated with young specimens of L.
anserifera\ others form a group which is attached to a small brown ball of vegetable origin.

Genus Poecilasma Darwin

When proposing the new genus Poecilasma, Darwin (185 i) knew five species belonging
to it ; he thought it probable, however, that several more would be discovered later.

This prediction of Darwin can be said to have been fully realised : I am not quite sure
that all descriptions of new forms have become known to me, but certainly eleven new species
have come to my notice up to date, viz. :

Hoek, Cirripedia "Challenger", 1883, 2 species.

Aurivillius, Studiën über Cirripedien, 1894, 4 species.

Aurivillius, Cirripèdes "Princesse-Alice", 1898, . . . 1 species.

Gruvel, Lépadides nouveaux British Museum, 1902, 1 species.

Hoek, Cirripedia "Siboga", 1907, 3 species.

Of some of these species it is questionable, whether they are really "good" species: for
example, as P. aurantium Darwin is considered by Gruvel l to be a variety of P. Kaempferi\
I think also, that it is doubtful whether P. amygdalum Auriv. and P. lenticula Auriv. are really
different from one another and from Darwin's P. fissum. But even then 9 new forms would
remain : a not unimportant increase to the number known to Darwin.

The mutual affinities of the species of Poecilasma are not easily understood. P. Kacmpferi
Darwin (with aurantium Darwin), P. dubiuin n. sp., P. carinatum Hoek and P. gracile Hoek
seem to form a natural group of true Poecilasmas, mainly differing from one another in the
shape and size of the carina. The species with the scutum composed of two segments form a
second apparently natural group : they are P. fissum Darwin (with amygdalum Auriv. and
lenticula Auriv.), P. cxcavatum n. sp., P. minutum Gruvel, P. tridens Auriv. and P. vagans
Aurivillius. Of these species P. cxcavatum n. sp. and P . minutum Gruvel may turn out to be
much more nearly related than the others. The remaining species: P. crassum Gray (with
P. tinguiculus Auriv.), P . obliquum n. sp. P. eburneum Hinds might be considered to form a

1 Gruvel, A., Cirripèdes. Expéditions du Travailleur et du Talisman. Paris, 1902.

3

third natural 1 1 1 * - first with small, the second with rudimentary, the third without t<

vrenience, such ;i classification may be used; but studying a few of the

lij one s i discovers, that the affinities between the different species cannot

: liy 1 1 1 « - shape or size or the greater or less development of parts of the capitulum

how how complicated the relations are I need onl) refer to the new species /'.

iund by the "Siboga" and to be described later. With its miniature terga it seems

naturally t<> bridge over the gap between /'. crassum with small and /'. eburneum without

■ ; ili-- arrangement of the spines on the cirri in /'. obliquum is < | uit < - different from

it is in /'. eburneum and shows that it is perfectly impossible t<> consider them as nearly

related. In tliis regard /'. obliquum seems to be nearly allied to /'. fissum\ in the presence,

however, "l a distinct line running from the umbo to the upper end ut" the scutum /'. eburneum

approaches to /'. fissum much more than /'. obliquum does.

I he geographical distribution of the species of Poecilasma is only imperfectly known as
yet. lwo species have been observed in the Atlantic and also in the Pacific; a very large
proportion ol the known species inhabit the Malay Archipelago, as may be seen from the
following list :

•&

ilasma Kaempferi Darwin (with /'. aurantium Darwin), Japan, Madeira. 350 a 400 m.

Gruvel), Gulf of Manaar, 775 m. (Annandale).
cilasma dubium n. sp., Malay Archipelago, 204 to 304 m.

ilasma carinatum Hoek, West Indies, Atlantic. Malay Archipelago, 600 to [633 m.

ilasma gracile Hoek, Australia, Malay Archipelago, 521 — 750111.

ilasma fissum 1 >arwin (with P. amygdalum Auriv. and P. lenticula Auriv. 1, Malay Archipelago,
Philippines, Australia \Vni\iu\ Andamans (AnnanüALI i. Low water.

ilasma excavatum 11. sp., Malay Archipelago. 289 — 304 m.
Poecilasma minutum Gruvel ?
Poecilasma tridens Auriv., Philippines. Depth ?
Poecilasma vagans Auriv.. probably Mast India. Pelagic?

Poecilasma crassum J. E. Gray, Madeira (Darwin), Azores (Gruvel). Depth -
Poecilasma unguiculus Auriv., Azores, 880 m.
Poecilasma obliquum 11. sp., Malay Archipelago, 204 — 304 m.
Poecilasma eburneum Hinds, Malay Archipelago, ? Red Sea (Wli.tnek . p> 00 m.

Poecilasma Kaempferi (with /'. aurantium) and /'. carinatum are so far as at present

known the only species inhabiting both the Atlantic and the Indian ( )cean. Ciu'vii. ' says that

rassum [from Madeira (Darwin and the Azores occurs also in the I'hilippine Archipelago,

Island of Bohol, but I suspect that this is an error; I do not know at any rate, on whose

thoritv this is stated.

ripcdien ciner Kci^e oach dem irbücher. Alil. fur Systetnalik. XII, iSgg.

n.. Malaysian Baroacles in the Indian Museum. Memoirs "f the Asiatic Bengal. L 5. 1905.

bisher beschrii ripedienarten. Archiv f. Naturgeschichte, 1S97, Bd I. II. ;.

Monographie des Cirrhipèd Pm,, p. 11".

The bathymetrical distribution is not known for all the species. P. vagaus was found
attached to a Nautilus and may be considered as a pelagic species, P. fissum lives on crabs,
one of which was found under a stone at low water (Darwin), another (a Palinurus-species)
was thrown on the shore (Aurivillius) : it is, no doubt, a true littoral form. P. eburneum was
taken by the "Siboga" at depths from 40 — 90 m. and seems to be a shallow-water form.
P. dubium, P. cxcavatum and P. obliquum were found at depths varying from 200 to 300 m.
P. Kaempferi, P. carinatum, P. gracile and P. unguiculus go down to 500 — 900 m., P.
carinatum being the only one taken at so great a depth as 1633 m.

1. Poecilasma carinatum Hoek. PI. I, fig. 1.

1883. HOEK, Cirripedia of the Challenger. p. 44, pi. I, fig. 8 — 10; pi. II, fig. I; pi. VII, fig. 6 — 7.

This species was taken during the cruise of the "Siboga" at

Stat. 177. Sept. 1, 1899. Lat. 2° 24.5 S., Long. I29°38'.5E. Depth, 1633 m. Bottom: dead coral
and stones, covered with manganese. (About half-way between Misool and Ceram).
and at

Stat. 284. January 18, 1900. Lat. 8°43'. 1 S., Long. I27°i6'.7E. Depth, 828 m. Bottom: grey
mud. Attached to a small stem of Clirysogorgia Jlexilis (Wr. & St.). One specimen.

Only one group of 3 specimens and one single specimen were taken. As my figure of
this species reproduced on PI. I of the Report on the "Challenger" Cirripedia is not quite
satisfactory, I have made a new drawing from the group of specimens collected by the "Siboga"
at Station 177.

This species affords a striking example of the world-wide distribution of some deep-sea
species; whereas the "Challenger" collected it off Culebra Island (West Indies) at a depth of
713 m. and off Ascension Island (Atlantic Ocean) at a depth of 768 m. it was taken by the
"Siboga" in the East Indian Archipelago at a depth of more than 1600 m. and again at a
depth of 828 m. According to Gruvel1 it is also found at the coast of Cuba at depths varying
between 600 and 900 m.

2. Poecilasma gracile Hoek.

1883. HOEK, Cirripedia of the Challenger. p. 46, pi. II, fig. 2 — 4.

This species was collected by the "Siboga" at

Stat. 38. April 1, 1899. Lat. 7°35'.4S., Long. ii7°28'.6E. Depth 521 m. Bottom: coral.
(North of Sumbawa).

The "Challenger" took one specimen off Sydney (Australia) at a somewhat greater
depth, viz. 750 m. In the collection of the "Siboga" it is represented by three specimens.
Two of them are attached to the spine of an echinid, the third to a much thinner spine -
perhaps of an echinid also. The largest specimen measures with the peduncle 11,5 mm., the
capitulum alone having a length of 9 mm. The specimen collected by the "Challenger" was
smaller, viz. 8 mm. entire length, its capitulum measuring nearly 7 mm.

1 Gruvel. A., Monographie des Cinhipèdes. Paris, 1905, p. 115.

5

il. sp. PI. I. li'. 2—4; PI. X, fig. I </ I tl.

ipitulum distinctly swollen about the middle, compressed towards the apex. Scuta oval,

ii short, rerga with the basal point obliquely truncated. Carina narrow, its keel

ar the inferior extremity. Basis <>t' the carina truncated, indistinctly forked. Peduncle

the length of the capitulum. X<> thicker spines in the notch "I the maxillae under the three

upper stronger spine-,

General appearance (PI. I. fig. 2 . Much like /'. Kaempferi Darwin but with ashorter
peduncle .nul .1 somewhat different carina. Valves quite white, the scutum distinctly striated.

Scutum distinctly striated. Apex pointed, a distinct ridge runs from the apex to

the umbo, the part between this ridge and the occludent margin hein-- broader than in P.

Basal margin and carinal margin together forming an almost continuous curved

line. Interiorly th<' basal margin is furnished with a strong rim and a tooth at the occludent,

basal corn<

fergum small in proportion to the scutum with the, basal end obliquely truncated.
. pointed. Delicately striated.

I arina (PI. 1. fig. 3) extremely narrow, its width only slightly increasing towards the
base. lts base truncated. miniature evrescences at both sides representing the prongs of the
tork of other species (PI. 1. fig. 30).

Peduncle cylindrical, short, less than one third the length of the capitulum, distinctly ringed.
Si ze. The largest specimen has a capitulum of 10.5 mm. length.

Mouth: Labrum with about 28 small beaddike teeth placed at a little distance from
one another; Pal pi with rather numerous, slender, not very long hairs.

Mandibles with four teeth and the inferior angle bifid; most of the hairs on the
surface are placed in little groups <>f two or three together.

Maxillae (PI. I, fig. \ with three stronger spines above the notch, a very short spine
near the third of these three at the beginning of the notch. no spines in the notch and four
short and slender ones at the other slope of the notch: a number of about 12 stronger as
well as -maller spines on the inferior. upraised part. Hairs on the surface of the maxilla not
ver) dense, in groups oi two or three.

1 'uter maxillae almost quadrangular, with the outer edge rounded; the surface and
the outer margin with numerous hairs, those of the margin curved for the most part.

Cirri. Firsl pair standing far from the second, with nearly equal rami: the one divided
in six, the other in seven segments, the first segment <>f both being indistinctly divided into
two. Surfai ach segment with a dense tuft i>( long hairs.

ond cirrus about three times as Ion- as the fust; the longest (posterior) ramus
13, the anterior ramus 11 segments.

Third cirrus with rami of 15 and 14 segments. Most segments are furnished on the

with four pairs of spines: the first and the second pair very long, the third shorter,

v short and delicate, nearly rudimentary; sometimes a fifth pair of extremely

delicate hairs is present; as a rule a slender spine is implanted between the two of each pair.

6

The cirri of the fourth-sixth pairs have about the same structure. The sixth cirrus
has rami of 18 segments; each segment bears four pairs of spines as on the third cirrus.
Ca u dal appendages extremely short with a tuft of hairs at the extremity.
Penis rather thick, slightly swollen at the extremity, where it bears a dense tuft of hairs.

H. M. S. "Siboga" collected this species on two different occasions:

Stat. 251. December 8, 1899. Lat. 5°28'.4S., Long. i32°o'.2E. Depth 204 m. Bottom: hard
coral sand. Two specimens and four with abnormal capitula.

Stat. 253. December 10, 1899. Lat. 5°48'.2 S., Long. I32°I3'E. Depth 304 m. Bottom: gray
clay, hard and crumbly. Four specimens.

General Remark. This species comes near to P. Kaempferi Darwin in some regards,
in others it seems to approach P. aurantium Darwin. Gruvel who investigated numerous
specimens of P. Kaempferi from Cape Bojador thinks that P. aurantium is a variety of P.
Kaempferi. He gave a new figure of this form — it leaves no doubt, I think, that the
specimens collected by the "Siboga" are really distinct from it. But the three forms: Kaempferi,
atirantium and dubium are certainly nearly related and belong to one and the same group
of species. .

Observation. The capitulum of four of the specimens collected at Station 251 is
more or less abnormal. They are small specimens and differ considerably from one another.
From the figures i,a — af, of PI. X these differences may be juclged.

Fig. ia represents the least abnormal one. It is a small specimen, the greatest diameter
of the capitulum measuring 5 mm., the whole animal 6,5 mm. only. It is slightly more swollen
transversely than the normal specimens, the occludent margin of the scutum being more strongly
convex. The principal difference, however, is in the tergum being distinctly divided into two
parts by a line running nearly parallel with the scutal margin.

Fig- 1 b gives the next stage of abnormality. The specimen has about the same size
as the foregoing: capitulum 5 mm., total length 6 mm. The division of the tergum into two
pieces is in this specimen more pronounced, the superior part being rounded off and overlapping
the inferior, especially towards the occludent side of the valve. In this specimen, moreover, the
carina is broken up into three parts: the largest being the inferior one, two smaller, narrower
parts lying between the inferior piece and the obliquely truncated basal end of the tergum.

Fig. 1 c represents a still more advanced stage of abnormality. The original shape of
the tergum is quite lost, an elongate oval, calcareous plate occupying its place, the apical part
of which reaches relatively far beyond the occludent margin of the capitulum. The superior
part of the carina is divided into different little pieces of shell, one lying immediately between
the carina and the abnormal tergum, of which it might be difficult to say whether it belongs to
the carina or the tergum. The shape of the capitulum of this specimen is broader, the occludent
margin of the scutum still more strongly convex than in the other specimens. The part of the
capitulum occupied by the scutum is considerably larger in consequence. The size of this specimen,
i. e. the length of the whole animal was 5,5 mm., 4,75 being the length of the capitulum.

Fig. ia? was drawn from the largest of the four specimens; it differs from the normal form
in other regards than the foregoing ones. In this specimen the whole shape of the capitulum is

7

tli.tt I wou ld hardly have taken the anima] for an abnormal /'. t////>i//w, if I had
,i quite different Station. Comparing the different valves with tho a normal

rgum in the first pla< trger, its apex is slighdy recurved and its I

not truncated but rounded. In the second place, the scutum is broader and il
much longer than in the typical specimens. Finally, the carina is not simply and
irl) bowed, but its upper part is recurved, and there is further a small isolated pi»
. which I think belongs to the carina, and which is placed between 1 1 1 « - tip of the remaining
part ol th.it valve and the inferior angle of the tergum. In tliis specimen, moreover, the peduncle
is longer than in the other specimens, its length being about . of the length of the capitulum.
The tut. il length of tliis specimen was 7,2 mm., that of its capitulum aboul 5 mm.

I do not know what circumstances or causes made these four specimens develop in such
an abormal way. They were most probabl) dead, when they wefe taken by the "Siboga". I
conclude this in the first place from the fact that the animals were hanging out of the capitulum
in a more or less deteriorated condition, in the second place from the circumstance that
numerous stalked Infusoriae are attached to the surface of the capitulum in all. As Darwin
ierved more than half a century ago, there is often very considerable variation in the
exact shape of the valves, more especially of the terga (l.c. p. 29 . In the present instance it is,
however, not so much variation in shape as that in three of the four specimens, at least, there is
abnormality in the process of calcification or shell-building. Under P.excavatum I describe another
■ >t' such abnormality without trying to explain its origin. This wil] be the task of future
investigators who study these animals in the fresh condition and at the place where they occür.

4. Poecilasma fissum Darwin. PI. X, fig. 2 — 5.

Poecilasma fissa Darwin. Monograph, Lepadidae, 1851, p. ioy, pi. II. fig. 4.

Darwin founded this species for a single specimen of Poecilasma which he took from a

spinose crab found under a stone at low water in the Island of Bohol, Philippine Archipelago.

Numerous specimens wen- taken from a Palinurvs, collected at rernate during the cruise

of II. MS. "Siboga". There are about six Iarger and about fifty smaller specimens. The larger

ones measure about 8 mm., 4,5 to 5 mm. coming on the capitulum, 3,5 to 3 on the peduncle.

Darwin says that the capitulum of his specimen was nearly a quarter of an inch long

and that its shape was gibbous, broadly oval. The description he gives of the capitulum, the

valves etc. applies so wel! to the specimens from Ternate that there remained tor me no doubt

.i> to these specimens really belonging to Darwin's Poecilasma fissa. There are liule differences,

ver, in the structure of the parts of the mouth, the cirri etc. Darwin's description was

founded on a single specimen which moreover "had long heen kept dry" and little differences

occur within the limits of a species. I would hardly insist on these differences, had they

■d what I suppose to 1»- the same species to 1m- described by Aürivillius as a new

name of /'. amygdalum^. for this reason especially, the following details of

ructure ma\ he of interest.

- dien b« u. K. Svensk. Vetensk H Ddl. XXVI, N" 7. 1894, p. 10.

8

Lab rum with a row of about 24 small teeth, standing close together; at each side the
5 or six outer ones are sharply pointed, the dozen in the middle being rather blunt. Pal pi small,
conical, with about five longer hairs at the tip and a few smaller ones along its inner side.

According to Darwin the fourth tooth of the mandible is pectinated. 1 found a small
tooth on the inner edges of the second and third teeth, one on the outer edo-e of the fourth
tooth and also one on the edo-e of the inferior anede.

The maxi 11 ae were unknown to Darwin. The upper part (PI. X, fig. 2 and 2a) is
furnished with three spines : two claw-like and the third rather straight and more delicate ; of
the two claw-like spines the first is one and a half times as broad and long as the second.
Under the upper part there is a deep notch, on the inferior margin of which two minute hairs
are planted. The inferior part of the edge of the maxilla is much producecl and bears about
ten unequally stout spines. Of these the one placed about the middle is by far the strono-est.

The second maxilla (PI. X, fig. 3) has the outline not truncated, but rounded; hairs
over the inner surface of unequal length, rather delicate and not very numerous. Near the
outer margin the surface shows, moreover, numerous rounded spots of peculiar aspect, which I
have not observed in other species, so far as I can remember.

Cirri of the first pair were lost in Darwin's specimen. They have unequal rami of
respectively 6 and 9 segments. These segments are broad, short, quadrangular, bearing at the
extremity a transverse row of numerous spines, which are longer than the segments themselves.

Cirri of the second to sixth pair much as described by Darwin. Concerning those of
the 6th pair the following may be pointed out : they have rather short pedicels and also short
rami of 11 and 12 segments. Their lower segments are as long as broad, the more distal grow
slightly longer, to about twice as long as broad, being slightly broader at the distal extremity;
the terminal segments of both rami are short and narrow. The spines form two groups or tufts
near the extremity of each segment (PI. X, fig. 4) : a dorsal and an anterior tuft, all of them
arranged in a transverse line. Darwin says that they are arranged in a circle, interrupted
widely on the two sides and, of course, it may be expressed in that way. But what is especially
characteristic for this species is, that the pairs of spines which as a rule in other Cirripeds are
seen at the anterior faces of the segments of the cirri are totally wanting.

Caudal appendages (PI. X, fig. 5) elongate, slightly broader in the middle, narrow
at the extremity, where they bear a tuft of long slender hairs, like a kind of pencil. They
reach to about the middle of the second segment of the pedicel of the 6th cirrus.

Penis long, pointed at the extremity, where it bears a tuft of delicate hairs.

General Remark. Aurivillius (1. c. p. 12) points out himself that there is a close
affinity between his new species (P. amygdalum) and Darwin's P. fissum. Vet he thinks they
are different, and to prove it he lays particular stress on the general form of the capitulum —
more oval, with a broader basis in P. fissum, more elliptical with a narrow basis in his P.
amygdalum. As I have said already, Darwin used for his description a specimen which had
long been kept dry and further, to judge from the material collected by the "Siboga", individual
differences occur in this species with regard to the shape of the capitulum. One might consider
some of the Ternate specimens as approaching more to Aurivillius' and others more to Darwin's

9

SIBOGA-EXl'EDITIE XXXI a.

fortn. Ili.u the eculiar arrangement of the spines on the cirri, which Darwin called most

abnormal n Vuriviluus' //<':•</ species also *die eigentümliche Anordnung der Cirren-

tchen des /'. findet sich bei diescr Ari wieder"), is by all means a circumstance

in favour "i iny \ii-w tint the) are really one and the same species.

llii'S i".>k still another species of Poecilasma from the same specimen of Palinurus^
thrown on the shore of the Island * Noordwachter", one of the 'Duizendeilanden" in the Java
He emphasizes that t H« - main difference between this species and /'. amygdalum is in the
structure of the »irri : these show according t" him quite different characters, especially with regard
t.. t' neut nt" the spines. In this second new species /'. lenticula from Palinurus^

the cirri bear two long spines on the anterior face and also two short ones distally from the
middle of each segment; on the dorsal face, spines are onlj seen in the sutures. Aurivh

figure ' ■ I .ii. VIII, fig. 28 to illustrate this detail of liis /'. lenticula but this
figure shows only spines in the sutures, on the anterior as well as on the dorsal side! Some
confusion either in the figures or in the descriptions given by Aurivlllius must have taken
but as lie points out that the difference in the arrangement of the spines is the most
essen tial, one cannot help thinking that alter all the reason for separating two forms of Poecilasma
as differei t species, which closelj resemble one another in other regards and live together on
the carapaci ol the same specimen of Palinurus, is not a very strong one.

According to Darwin Poecilasma fissum occurs at the Philippines; according to W'i ltni r '
it has been collected by Fischer at New Caledonia. by Whitelegge at Port Jackson, by himself
at Jaluit (on Palinurus) and by Schaüinsland at Honolulu.

The label accompanying the "Siboga" specimens only says that they were found on a
Palinurus at Ternate.

- Poecilasma excavatum n. sp. PI. I, fig. 5 — 10.

Capitulum with seven valves, the scutum being divided into two segments by a fissure
nearly parallel to the occludent margin. Tergum with an excavation in the scutal margin near
tli- occludent margin to receive the tip of the occludent segment of the scutum. Carina narrow,
keeled near the inferior extremity, terminating in a disc.

General appearance. Capitulum oval, less than twice as long as broad, with the
apex pointed, rather thick, swollen. Valves unitcd without chitinous interspaces, peduncle cylin-
drical, narrow where it is attached to the capitulum (PI. I, lig. 5).

5i u turn. The larger segment strongly bowed, with a short basal margin and pointed

apex. There is a tracé ,,f an internal basal rim, but no tooth at the rostral angle is present.

I.ike the other valves the scutum is very delicately striated. The smaller segment is also

distinctly bowed, it terminates in a point at the base and has the tergal margin rounded so

tly into the excavation of the tergum.

Tergum triangular with a very characteristic excavation at the scutal margin near the
rgin PI. I. fig. 6).

1 eim h dem l'aciric (Schaüinsland 1896 — 97). Cirripedien. Zoologische Jahrbtlchcr.

[1,1 (| I H7-

1 1

Carina narrow, broader at the lower part which is distinctly carinated, terminating in
a spatula-shaped disc which is embedded between capitulum and peduncle (PI. I, fig. 7 and -ja).

Peduncle short, about half the length of the capitulum, cyündrical ; narrow near the
place of its attachment to the capitulum, swollen about the middle of its length. Surface with
narrow rings indicated by darker chitinous transverse rings.

Si ze. The capitulum of the largest specimen collected was 11,6 mm. in length. The
other specimens are however considerably smaller.

The study of the animal contained within the capitulum has yielded the following results:

Mouth. In general as in the other species of the genus, for example, as in P. dubium.
Mandibles with a relatively greater distance between the first and second teeth, second,
third and fourth nearer to one another on the other hand. Maxillae with no larger spines
in the notch beneath the three great upper spines, with five or six slender spines on the slope
at the other side of the notch. The spines on the inferior upraised part of the maxilla slightly
smaller and less numerous (about 10) than in P. dubium.

Cirri. First pair at a distance from the second, with nearly equal rami each divided
into five segments. Outer surface of the segments with numerous and long hairs, a transverse row
of rather strong hairs or spines near the end of the third and fourth segments and terminallv
on the fifth segment also.

The other cirri as in the other species of the genus. The number of spines on the front
side of the segments of the cirri N" II — VI is as a rule four pairs, a fifth pair being often
indicated by a couple of extremely short hairs. The number of spines on the last segments is
smaller. The number of the segments in the cirri II — III is 10 and 11, in the cirri IV — VI
1 1 and 1 2.

The eau cl al appendages are slender, about as long as the first segment of the
pedicel of the sixth cirrus. They bear a dense tuft of very long hairs along the outer side in
the last third part of their length (PI. I, fig. 8).

Penis thick, ringed especially about the middle of its length, terminating in a much
narrower and curved part. Extremely delicate and sparse hairs on the surface, a tuft of slightly
stronger hairs at the extremity.

H. M. S. "Siboga" collected this species twice, viz. once five specimens at:

Stat. 253. December 10, 1899. Lat. 5°48.2S., Long. I32°I3'E. Depth 304 m. Bottom: gray
clay, hard and crumbly.

and half a dozen specimens at :

Stat. 12. March 14, 1899. Lat. 7°i5'S., Long. U5°i5'.6E. Depth 2S9 m. Bottom: coarse
sand with broken shells.

Of the latter specimens one was attached to a small piece of the scale of a Crustacean.

General Re mark. This species belongs to the same section of the genus as Darwin's
P. fissum and the species P. amygdahim, P. Icnticula, tridens and vakans of Auriviluus: all
species with 7 valves, the scutum in each being formed of two closely approximate segments.
The very characteristic excavation of the scutal margin of the tergum and the spatula-shaped

1 :

na render ii easj enough to distinguish this species from those it shows
affinit) i|--

ler with Poecilasma excavatum^ /'. dubium and /'. obliauum, a form of Poecilasma

ibout the nature of which I dare not pronounce an opinion with certainty. This

• nted by a single specimen. [*he length of its capitulum is ~ mm., the peduncle

as long as the capitulum, cylindrical, distinctly ringed. It has the scutum divided into

jments and, what lias never been observed in any species of this -'-mis, the tei

divided in two segments. The fissure runs in continuation to the fissure oi the scutum

and lias the same character in the terga of both sides. rhe terga do nol look (juite normal,

however, as the) are onlj partij calcified: a relatively large part ol the surface ol the tergum

being occupied l>\ chitinous substance.

In fig. 9, PI. I 1 give a drawing « » i" the outlines of this curious form, magnified slightly
over 5 diameters; in fig. 10 the apex «'t" the scutum is represented with the division ut* the
m magnified 36 diameters. 1 feel at a loss to decide whether this form is normal, in which
case it would represent a ven- interesting section of the genus Poecilasma^ or what seems more
probable provisionally, a pathological abnormality being caused by mutilation and regeneration
of the parts that have been broken off. . . .

N.B. This form has been labelled /'. excavatum^ varietas.

At the same Station 253 still another form of Poecilasma was collected. It is represented
by a single specimen only; likt- /'. fissum, /'. excavatum etc. it has the capitulum composed of
; valves and it is also nearly related to these species in other regards. lts peduncle seems
to 1"- broken off, but the surface of the part remaining bears numermis microscopic spines. The
smaller segment of the scutum terminates at its tergal extremity in a point, so that no real
tergal margin is formed: in this regard this form resembles P. fissum more than P. excavatum.
It differs from both species in the smallness of its terga, its carina being a little longer than
in these species.

The length of the capitulum of this form is 5 mm., that of the part of the peduncle
found attached to the capitulum about 2 mm. It was collected at a depth of 304 m. As the
specimen does not seem to be quite complete I think it better not to introducé it into the
system under a specific name.

6. Poecilasma obliquum n. sp. PI. I. fig. 11 22.

Capitulum slightly unsymmetrical, tergum rudimentary and concealed in the membrane
een the two scuta; carina with a prominent heel, terminating in a small imbedded fork.
i short, partly rudimentary.

Genera] appearance (PI. I, fig. 11 and 12). Capitulum of oblique lenticular shape,
'n a way to the peduncle, that its base is covered at the right side more than at
l in the larger specimens distinctly furrowed.

S cu t u m. Seen externally the basal margin can hardly be separated from the carinal
margin, but an internal basal rim shows how far the basal margin extends (PI. I, fig. 13).
Occludent margin curved, near the basal angle slightly turned inward. A triangular tooth is
placed internally near the basal angle. The occludent margin meets the tergal margin almost
without forming an upper angle. Carinal and tergal margïns blend into one another quite
oradually. The two valves, of right and left side, are equally convex. Seen externally the
surface of the scutum in the larger specimens is not smooth but furnished with a very distinct
series of furrows parallel to the carino-tergal margin.

Tergum (PI. I, fig. 13 and 14). Ouite rudimentary, triangular. The basal angle is not
pointed but obliquely truncated.

Carina (fig. 150 and 15^). Little over half as long as the carinal margin of the scutum,
narrow and internally convex. The exterior surface is carinated and has a prominent heel, in front
of which the little fork which is imbedded between the capitulum and the peduncle is attached.

P e d u n c 1 e cylindrical, narrow and extremely short, in the largest specimen covered at
the right side for a great part by the overhanging scutum.

Size. The largest specimen has a capitulum of 7 mm., the whole length being slightly
over 7,5 mm.

Mouth. Labrum (fig. 16 and 16a) bullate, the front part overhanging and triangular.
Crest hairy and pectinated, i. e. furnished with a row of smaller and larger, sharp triangular
teeth placed close together. Palpi small, triangular, hairs neither very numerous nor very long.
Mandibles (fig. 17) with four teeth and a rudimentary inferior angle, produced into a fine
point. The teeth are nearly equidistant, tooth 1, 2 and 3 finely pectinated on the inferior side.
Mandibles on the front part more densely hairy than in the other species of the genus.
Maxillae (fig. 18) with a notch beneath the three upper spines, hairs in the notch delicate;
the not very numerous (6 — 8) spines beneath the notch relatively delicate also; covered with
dense hairs. Outer maxillae (PI. I, fig. 19) quadrangular, rounded at the corners, hairs not
very dense nor very long.

Cirri, short, very unequal, more or less rudimentary. The cirri of the right side as a
rule smaller than those of the left side. The first pair is not far from the second pair. Both
cirri of the first pair have unequal rami, but each ramus is composed of 7 segments. The
ist cirrus of the right side has the shorter ramus about half as long as the longer, in that of
the left side the difference is not so great. Each segment bears a transverse row of strong
spines at the extremity and these grow stronger and become more numerous distally. The top
of the last segment bears five or six spines. The concave side of each ramus has a group of
spines at the extremity of each segment, the convex side is furnished with a row of very
delicate hairs.

The second cirrus of the right side has unequal rami both composed of eight segments ;
that of the left side has the posterior longer ramus composed of 10, the anterior ramus of
8 segments. The segments are, as in the first cirrus, short, quadrangular or even broader
than long. Each segment has a transverse row of spines at the outer side near the extremity,
more strongly developed in the terminal segments and towards the dorsal side of each ramus.

13

' I

■|-)„. jmi, nent has .1 transverse row ol more delicate spines or hairs and

• • .... ide especiall) of the lower segments.

righl side with both rami much shorter than those of the left side.
1 rus of the left side have 11 and 9 segments; form of the segments

spines much like in the second cirrus.

iiirth cirrus of the right side quite rudimentary, rami very unequal, both composed of

with smal) groups of hairs al the extremity of tl lenl 1 >n the lefl side

:. — d of two nearly equal rami composed of m segments. The fourth left

. has the same structure as the left one of the fifth pair (PI. I. fig. 20): the groups of

i :. dorsal side of the rami al the extremity of the segments and growing stronger

in the terminal segments are very characteristic for both cirri.

The right-hand cirrus of the fifth pair is extremely small, rudimentarj PI. I. fig. 21). Itdiffers

from that of the fourth pair in having quite equal rami. They are composed of five segments.

Both cirri of the sixth pair have a stronger ramus of 12 broader segments and a more

slender ramus of 1 1 segments. llu\ bear, at the extremity of the segments towards the dorsal

the same groups of stronger spines as in the left-hand cirrus of the .\'u and s'1' pair: at tin ■

anterior or concave side. each segment bears as a rule one pair of spines or a larger spine

impanied by two or three more slender ones.

Caudal appendages (PI. I. fig. 221 shorter than the first segment of the pedicel
of the sixth cirrus. slender with a dense tuft of hairs near the extremity and a few hairs along
the sid'

Penis cvlindrical, growine thinner towards the extremity, with very numerous and ven
delicate curved hairs scattered over its surface; a tuft of such hairs at the extremity.

1 g g s numerous. long oval. Longest axis 0,2 to 0,22 mm., shortest axis 0,08 mm.

This species was taken in half a dozen specimens, only two of which seem to be
full-grown, at :

Stat. 253. December 10, 1899. Lat. 5 4S.2S., Long. 1 320 13 1".. Dcpth 304111. Bottom: gray

clay. hard and crumbly.
Stat. 251. December 8, 1S99. Lat. 5 2S .4 S., Long. 13: o.: K. Dcpth 204 m. Bottom: hard

coral sand. One small specimen.

General Kern ark. This is a very remarkable species. Were it not for Dakwin's

(Hinds' /'. eburneum. 1 would have feit greatly inclined to consider it as representing a new

genus. As already observed l>y Hinds :who therefore propose.1 the name Trilasntis for this

Cirripedi and as described in detail by Darwin, the terga are "entirely" absent in /'. eburneum

and at tirst I did not find them in /'. obliquum either. Yet on studying the capitulum more

illy, I discovered the terga tremely minute triangular pieces, hidden in the folds oi

: membrane uniting the two scuta over the upper end of the carina. In this regard the new

'turn with its quite rudimentary terga bridges the cleft which separates /'. crassum

with small (DARWIN says "rudimentary" terga — luit they are well-developed and even large

with those of /'. obliquum] terga and /'. eburneum with no terga whatever.

of the parts composing the mouth in /'. obliquum differs in several regards

1 ;

15

from what it is in other species of the genus, yet these differences are perhaps not so great
as they give one the impression of being at first sight. In P. obliquum the teeth of the
labrum are triangular, approximated and of unequal size, whereas in the other species of the
genus they are bead-like and removed from one another. In P. eburneum, however, I found
the teeth on the lateral parts of the labrum sharply pointed, triangular, and in P. fissum the
same is the case. In P. obliquum the first-third teeth of the mandibles are finely pectinated;
traces of such a pectination are, however, observed in P. fissum also. In P. obliquum the
somewhat rudimentary cirri have short quadrangular segments and transverse rows of spines,
the pairs on the anterior faces being represented by a single pair only. In this regard this
species comes nearest to P . fissum — the difference being that the spines in the latter species
consist of two tufts, an anterior and a dorsal, whereas they form a more continuous row on
the cirri of P. obliquum.

So far as the shape and structure of the valves are concerned, P. cburneum of known
species of Poecilasma is the nearest relative of P. obliquum ; with regard to the structure of the
body P. fissum has no doubt greater affinity to P. obliquum than any of the other species.

7. Poecilasma cbtirneum (Hinds). PI. X, Fig. 6 — 7.

Tri/asiuis eburnea Hinds, Voyage of Sulphur. I. Mollusca, 1844, PI. XXI, fig. 5.
Poecilasma eburnea (Hinds), Darvvin, Monograph, Lepadidae, 185 1, p. 112, pi. II, fig. 5.

H. M. S. "Siboga" collected specimens of this interesting species on several occasions.

Darwin's descriptions of the species of Cirripedia are as a rule so good that hardly
anything need be added. Having made acquaintance with the curious species P. obliquum and
having discovered its miniature terga, I was anxious, however, to investigate Hinds species
a-new and to compare its structure with that of my new species.

With regard to the capitulum I found Darwin's description exact : the terga are entirely
wanting, the shape of the scuta and carina, the way in which the capitulum is placed with
respect to the peduncle etc. are entirely as üarwin has them. As to the structure of the parts
of the mouth, the cirri etc. little differences, however, were found and a few observations may
therefore be permitted here.

The labrum has small teeth along its crest, those in the middle are bead-like; at
each side, however, half a dozen are sharply pointed and slightly distant from one another.
The hairs on the tip of the p a 1 p i are rather long, so long as to touch when the two palpi
are turned towards one another. The inferior angle of the m a n d i b 1 e is spine-like, the side
directed towards the fourth tooth bears an extremely minute tooth near the extremity - - whence
the angle is bifid, as Darwin says. Maxillae with two larger and a third somewhat smaller
upper spine, a couple of rather delicate and short spines at each side of the main notch; the
inferior upraised part is not straight, but forms steps, the excavations being indicated by Darwin
as minute notches. Second maxillae (PI. X, fig. 6) truncated, broad, nearly quadrangular
with rounded corners; hairs at the tip and along the inner surface rather numerous and not
very long.

15

i 6

With regard to the structure of the cirri the main difference between Darwin's

ription and what I have found is, that I tliink the unequality "f the rami :ilm< >^t unimportant,

and further, that the segments of the rami of th( rri are distinctly protuberant.

er the <irri are short, the segments of the rami being bul 1 ï 1 1 1 * - longer than broad and

j numerous; the last pair has rami of i ; and i i segments in one of the specimens I

ited rhese segments have the ordinar) 3 or 4 pairs of spines on the anterior face,

l>ut as the segments are rather short these pairs stand close together and form groups of spines,

a "brush" as Darwin s.i\->. with the more or less numerous lateral marginal spines. The dorsal

sidi ment bears the ordinary dorsal tuft near th( mity PI. X. fig. ;

The caudal appendages .in- short, less than half the length of the lower segment
of the ped ' the sixth cirrus; they are slightlj swollen about the middle, the rounded

mity being distinctly narrower. rhe distal third part is thickl) clothed with delicate bri
ling i>ut in all directions.

During tin- cruise <>f the "Siboga" this species was collected at:

About St.it. 51: in Streel Molo. Depth 54 — 90 m. 1 small specimen.

Stat. 79. June u. 1899. Lat. _• 43 S.. Long. 11 7° 44 I ■ Depth |i 54 m. Bottom: fine

sand [Borneo Bank]. Attached i<< the spines of a Cidaris bispinosa Lam. 8 specimens,

most "f them small. three larger. The greatest diameter of the largest is about 7 mm.
Stat. "il'. June 12, [899. Lat. 2 ;S.;S.. Long. 117 46 I I' pth 54 m. Bottom: line coral

sand [Borneo Bank: 5 miles N.N. E. from Station 79]. 4 specimens, greatest diameter

of largest 7 mm.
. June [3, [899. l.at. 2 25 S.. Long. i 1 7 T 4 3 11. Depth 40 — 50 m. Bottom: line coral-

sand. 4 specimens, largest not quite 5 mm.

General Remark. This species, which was known to Darwin from specimens from

inea only, may now be considered to occur at different places in the Malay Archipelago.

It lives attached to the spines of Echinus, Cidaris and perhaps other forms of Echinidae and

seem 1 down to depths of over 50 m. According to W'1.1 ixer ' the Berlin .Museum possesses

specimens of this species collected in the Red Sea l>v I.ii-hs'-j.

Genus Dichelaspis Darwin

Darwin (185 1) instituted the genus Dichelaspis tor those Lepadidae which have 5 valves.
generall_\ appearing like 7 from each scutum being divided into two distinct segments united
at the rostral angle; he distinguished live species of the genus. When my report on the
"Challenger" Cirripedia was publishe ■ ; the number of known species had increased to

nine. Since that time the number has increased considerably ; Weltner, publishing a list in
• the then known sprei.--, of Cirripedia, was able to count 18 species, or even io. as
. slight omission one of the 8 new introduced into science li\- Aürivillius was left

out iMk. Weltner also mentioned two new species which Stebbing ' described in 1

1 W W.. '. ' v f. Naturg. i s., ,-. |„! |. n. -. p, ...j ;.

'■'■ . Ibidi m, i'. 241.

■ . W.. Studiën etc. r -28.

■■. \ 1 • a iS— 19.

t6

i7

but, of course, five other new species the descriptions of which have been published in 1900
by Gruvel \ two described by Lanchester 3 in 1902 and one by Annandale in 1906 3, could
not fio-ure in his list. Thus 25 species in all of this genus are now known : in Gruvel's latest
publication* a synoptical table is given for the determination of these species. He even enumerates
(without Annandale's species of 1906) 25 species, as he also reckons to this genus a Lepadid
considered by Stebbing 5 to belong to another (and new) genus for which the name Trichelaspis
had been proposed by that carcinologist.

The cruise of the Dutch gunboat "Siboga" has supplied us with several forms belonging
to this o-enus and I find that most of them must be considered as novae species. But before
entering on the description of these forms, I consider it useful to give a summary of the
descriptions of the known species in order to be able to judge of their relations and to under-
stand the difficulties of the classification.

Aurivillius (1. c. p. 20 — 26) was the first who discovered a species of Dichelaspis, and
even five of them, without terga; in one of these species the carina is also wanting. I was at
first inclined to separate these species from the genus Dichelaspis. It would perhaps be more
in accordance with Darwin's original views, when only such forms were accepted as species of
this genus which had five valves and a scutum divided into two segments. This at least is the
original diagnosis of the genus. Stebbing therefore pointed out, that it would be difficult to
maintain the species of Aurivillius as species of the present genus. Yet looking at the question
again I finally embraced the opinion of Aurivillius in this matter. The structure of the body
of these problematic Dic/ie/aspis-species corresponds essentially with that of the typical, the
genuine, species of the genus, and in one of these species (D. cor) not only are the scuta
very typical Dic/ie/aspis-scuta, divided into two segments and with the primordial valves at
the rostral angle, but the capitulum has the position of the tergum distinctly indicated, as
it is limited by a chitinous cushion, towards the margin of the scutum as well as towards that
of the carina. Thus it would be extremely difficult and even unnatural not to consider that
species as a Dichelaspis, and once this is agreed upon, the other species are to be accepted
also, as they represent further stages in the degeneration of the valves of the capitulum in the
same direction as shown by D. cor, the last stage - - so far as known at present - - being
occupied by D. bullata Aurivillius, which species has no terga and no carina.

Gruvel's new species D. Maindroni and D. Coutierei much resemble the form called
D. cor by Aurivillius and these belong by all means to the same section of the genus, which
section now counts seven species: five of Aurivillius and two of Gruvel. These seven species
most likely have another point of agreement, in that they are all living in a semi-parasitic way
in the branchial cavity or even attached to the branchiae of large brachyurous or macrurous
crustaceans. Four of the species of Aurivillius were even taken from the same Palinurns, not
species only but specimen, found stranded on the coast of one of the Thousand Islands, Java.

1 Gruvel, A., Bulletin du Muséum d'histoire naturelle, 1900, n" 3, p. 109.

2 Lanchestf.r, W., Crustacea of the Skeat Expedition. Proceed. Zool. Soc. London, II, 1902.

3 Annandale, N., Stalked Bainacles in the Colombo Museum. Spolia Zeylanica, III, Part XI, 1906.

4 Gruvel, A., Monographie etc. 1905, p. 140 — 141.

5 STEBBING, T. R. R., A new Pedunculate Cirripede. Ann. & Mag. Nat. Hist. (6), XIII, 1S94, p. 443.

17
SIBOGA-EXPEDITIE XXXI a.

id standing ol these seven sp< ■ im< ol which mi closer
abl) I" found i" I"- identical; but I wish only to j >« >in t <>ut that there is,
to admil .1 causal nexus between the simplified structure of the
of life of these forms.

jroup ol more or less degenerated forms, i

\» remain. Of the latter those species in which the valves have the

pment and show the greatesl resemblance to the valves of the nearly

and LepaSy are most likely t<> repn lie more original form. In

ard the described bj me ^ D. resstlis, by Annandale as /). tenuivalvata and by

/>. occlusa are the first to 1"- named: their scutum is rather broad, their tergum

the triangular shape of the species ol Lepas and their carina is likewise broad. Ni \i come

D. Warvricki Gray and those which are nearly related to it: D. Hoekt Stebbing,

Stebbing, />. alata Auriv., D. Aurivillii Gruvel and />. equina Lanchester. In all

■ - the scutum is composed of a narrow occludent segment and a much wider basal

lent which, as a rule, has a triangular shape. With the more or less developed and 1

tergum these valves cover a good deal of the surface of the capitulum. The carina of these

i s terminates in a rectangularly infiected disc ' extending over a good deal of the base

of the capitulum. These five species (with D. Forresti Stebbing), six : form together another

natural ^rouj» of species in die genus Dichelaspis. It is quite another question whether

all these forms are really distinct species — but this can only be made out by comparative

study of all the original specimens, which study is not lor me to undertake.

Which species should come next? To judge trom the form of the carina />. pellucida
Darwin would be nearly related to />. Warwicki Gray; to judge trom the form of the tergum
rthogonia would be the nearest relative of the latter species and I think it would Ik- very
difficult to decide which characteristic is the more important. Then- remain 12 species, all of
them with rather narrow valves lea\in^ a great deal of the capitulum uncovered. These can
easily be divided into three natural and distinct groups. /). orthogonia Darwin forms a group
of its own amongst the hitherto known species: it has a triangular tergum with three (four)
prominent ridges and the carina terminates downwards in a small crescent-shaped cup: it is to
this group of the genus that two of the forms collected by 11. M.S. "Siboga" in the Malay
Archipelago and to be described later belong. />. pellucida, which has the carina much like
that of l>. Warwicki, has the tergum of quite a different shape: like a battle-axe as Darwin
ribes it -. not only D. Grayi Darwin luit also D. lepadiformis Gruvel come very close to
D. pellucida and if they are indeed distinct species they really form together an extremely
natural group.

The ,;inic holds for IK Lowei Darwin, D. Darwini Filippi, D. neptuni Macdonald,

rioa 'i( his species /'. <;/.//</ terminates in a fork. Should this reall)
\. liad at his di ecimen only and this specimen most probably has nut been di:

1 think it is h.inllv 1 lie >hapc ol' the terminal pari of the carina

iiinl part \'. really united by a disc-lil

- to lic a Dichelaspis. I think it bclongs to the same

i.S

19

D. Aymonini Lessona et Tapparone Canefri, D. sinuata Aurivillius, D. trigona Aurivillius and
D. Vaillanti Gruvel. All these species agree in so far as they have rather narrow valves leaving
a great deal of the capitulum uncovered, and also in that the carina terminates downwards in
a fork. But here I wish again to emphasize, that though we must accept all these species for
the present I am not convinced that they really are so many or so distinct.

The forms of Dichelaspis collected during the cruise of the "Siboga" belong to five
different species: D. Weberi n. sp., D. Nierstraszi n. sp., D. Tydcmani n. sp., D. Versluysi n. sp.
and D. orthogonia Darwin. The four new species are named after those who have the merit
of having done the scientific work on board the ship during the cruise. Of the new species
D. Nierstraszi and D. Tydeuiani are both nearly related to D. Warwicki Darwin and doubtless
belong to the same section of the genus; D. Weberi and D. Versluysi show — the latter more
than the first - - a well-marked affinity to Darwin's D. orthogonia.

Thus we would now have 32 species of Dichelaspis, which might be classified according
to their mutual affinities in the following way :

I. Species, in which the valves show the highest development, covering a great deal of the
surface of the capitulum.
D. sessilis (type-species), D. icnuivalvata and D. occlusa (3 known species).

II. Species, in which the valves show a somewhat less development, with a relatively broad
scutum and the carina terminating in a rectangularly infiected disc.
D. Warwicki (type-species), alata, anliguae, equiua, Aurivillii, (Forresti), Hocki, Nier-
straszi, Tydemani (9 known species).

III. Species, in which the valves are considerably less developed than is the case in the species

of group II, in which however the carina has the same form as in the species of that group.
D. pellucida (type-species), Grayi, lepadiformis (3 known species).

IV. Species having the same development of the valves as those of group III, but with a

tergum corresponding in form to that of the species of group II.
D. orthogonia (type-species), Weberi, Versluysi (3 known species).

V. Species with five valves, the narrowness of which causes a great part of the capitulum to
be uncovered.
D. Lowei (type-species), Aymonini, Darzvini, ncptuui, sinuata, trigona, Vaillanti (7 known
species).

VI. Species with three valves only, terga wanting.

D. cor (type-species), angulata, aperta, Coutierei, cuneata, Maindroni (6 known species).

VII. Species with two valves only (terga and carina wanting).
D. bullata (type-species), 1 known species.

Of these 32 species about one half (14, 15 or 16) have been observed in the Malay
Archipelago, viz.

D. occlusa, East coast of Malay Peninsula: Tungganu (Lanchester).
D. Warwicki, off Borneo (Darwin), Java Sea, near Batavia (Aurivillius).

19

i and Islands | Ai rivii i i
/' i M.tlay Peninsula: Tren Lanchestei

M.il.u Vrchipelago, differenl Stations, see later!
tr Saleyer, see later!
■, Indian < >cean 1 >arwin), < >riental species with fairly extensive distribution Annandai i l.
i ipical, Indian or Pacific ' >ceans I ) vrw i
i ui Greal Kei Island, see later!

Malaj Archipelago, differenl Stations, see later!
/» ./,/. M.il.iy Archipelago, differenl Stations, see later!

D, •■ . Java Sea rhousand Islands (Aurivilliuj

/>. trigona, Java Sea rhousand Islands (Aurivillius).
D. '). Java Sea: Thousand Islands (Aurivillius).

/>. aperta, Java Sea rhousand Islands (Aurivillius).
D. cungata, Java Sea: Thousand Islands Aurivii
D. Maindroni, Sumatra (Gruvel).
D. lullata. Java Sea: Thousand Islands Aurivillius).

The seven species of Aurivillius enumerated in the above list were all of them taken
from one and the same stranded specimen of a Palinurus spec. They were found attached to
the branchiae or to the interior wal! of the branchial cavity of that crayfish. The name of the
species of Palinurus is not given, but it is no doubt permitted to suppose that it was a littoral
form no deep-sea species. Dickelaspis Maindroni^ the species described by Gruvei , was also

found attached to a Palinurus (whether all of them, or only those collected by Mr. Maindron
is not distin ctly indicated by Gruvel) and also seems to be a littoral form. For D. Warwicèi,
pellucida and Grayi no definite data with regard to their bathymetrical distribution could be
given by Darwin. Thej are most probably all of them littoral forms: D. Warwicki was found
attached to a crab, Grayi to the skin of a sea-snake, and pellucida also to a sea-snake - they
an- most probably forms which live at the surface of the sea. D. equina lives on shallow-water
crabs and likewise D. occlusa.

The species collected by ll.M.S. "Siboga" were found at different depths:

Dickelaspis Tydemani n. sp. at a depth ol [O — 25 m.
Dickelaspis Versluysi n. sp. at a depth of 22 — ^2 m.
Dickelaspis Nierstraszi n. sp. at a depth of 27 — 59 m.
Dickelaspis orthogonia Darwin at a depth of SS— 112 m.
Dickelaspis Weberi n. sp. at a depth of 560 m.

The last-named is thus the only true deep-sea species of the collection, and as wil! be

1 from the description it is the largesl of the known species. This is a peculiarity which also

for many other deep-sea species of Cirripedia (e.g. Scalpellum- and Verruca-specics).

Tl known deep-sea species of this genus D. sessilisj was collected by the Challenger

al a depth of about [800 m. All the other species are littoral forms, living

oing down to d--|,ths of 30, 50, 100 m. at most. In accordance with this

2 T

all the species, so far at least as our present knowledge goes, have a limited geographical
distribution. We need not forget, however, that our knowledge is rather imperfect as yet. In
one of the last papers published on Cirripedia (that in which Annandale describes the stalked
Cirripeds of the Colombo Museum) we iïnd in this regard as new facts that D. equina Lanchester
from the east coast of the Malay Peninsula is common on the east coast of British India
and that D. pellucida Darwin is an Oriental species which probably has a fairly extensive
distribution. The latter, which has only been taken on sea-snakes, has not been collected during
the cruise of the "Siboora".

£>

i. Dichelaspis Nierstraszi n. sp. PI. II, fig. i — 7.

Capitulum much compressed, with the apex produced. Scuta with the basal segment
about as wide as the occludent segment, its carinal margin being very much hollowed out;
terga with three unequal marginal projections the longest of which is nearly as wide as the
occludent segment of the scuta. Carina terminating in a disc.

General appearance (PI. II, fig. 1 and 2). Capitulum compressed, flat, slightly convex
in the middle, with the apex produced. The valves are covered by a membrane which is thick
and hairy especially in old specimens. In very young specimens the membrane also bears
chitinous hairs. The carina is separated by a wide space from the scuta. Peduncle cylindrical,
shorter than the capitulum.

The valves cover a large part of the surface in very small specimens (PI. II, fig. 2 a).
In these the shape of the valves is also different.

S cu turn (fig. 4*7). It is formed of two slightly divergent and about equally broad parts,
hanging together by means of a very narrow bridge. The occludent segment one fourth longer
than the part representing the basal segment; both segments with the upper part the broader.

In some old specimens from the Tual anchorage, Kei Islands, the occludent segment
of the scutum is considerably wider than the basal segment.

In very young specimens (fig. 2 a) both segments of the scutum are relatively broader;
this is especially the case with the basal segment, the shape of which is nearly triangular, with
the carinal margin hollowed out. Fig. 2>a represents the scutum of a middle-sized specimen,
remarkable for having the upper part of the occludent segment rather narrow.

Ter gum (fig. 4.Ó). It has the lower part of about the same width as the occludent
segment of the scutum ; a narrow occludent segment forms a second projection which is separated
by a deep notch from the carinal segment; the apex of the occludent segment of the scutum
extencls in the direction of this notch. A third and very short prominence is placed high up
on the carinal margin just above the apex of the carina.

In very young specimens (fig. 2a) the three prominences of the tergum are not so well
developed as yet; the middle one, the longest of the three, is the only one distinct. In middle-
sized specimens (fig. 7,6) the tergum has about the shape as the full-grown individuals.

Carina (fig. 5 and 50). Much bowed, narrow, deeply concave within, extending up
between the terga for %vds of their length, with a very characteristic curvature directed inwards
just above the basal part. Downwards it terminates in a rectangularly inflected, deeply imbedded

lightly wid< remity, which terminally is not ver) deeply notched.

'Lu bul hollowed out in the middle; ii i across over more than

thirds "i tl litulum, beyond the middle ol the basal segment of the scutum.

1', idrical, ilightly longer than half the length of the capitulum,

that lenj a the capitulum in specimens sitting crowded together;

,, in the old specimens, collected at Tual anchorage, K< :i Islands, one of which

,1 PI, II. fig. i. The peduncle is distinctly ringed at the surface; the chitinous covering is

studded with Mum beads of chitin externall) and shows, in old specimens, scale-like exeri

with them. Delicate hairs are planted on tin- blunt beads of the surface; they

more conspicuous in young specimens than in the full-grown. In the very old

s from the Kei [slands the surface of the peduncle, like that <>f the capitulum, has a

oating.

I in- largest specimen had a capitulum ut' 7,5 mm., most individuals however, are

r than 4 mm. and a good many of the specimens art: still smaller. The capitulum ol

figured, fig. 2d. only measured 2 mm., that of (114. 1, o mm.

Mouth. Lalirum bullate, with smal! palpi bearing numerous bristles, some of them

at the apex. Teeth about t8, bead-like distally, triangular and close to one another

in the middle.

Mandibles (fig. 6) narrow, with tour teeth and the inferior angle formed by a group
of very small teeth: teeth 2, 3 and 4 bearing an additional tooth near the extremity.

Maxillae (fig. 7) with a notch beneath the three upper spines, one of which is much
stronger and mie much shorter than the third. In the notch which is wide but not very deep
four slender spines are planted, and the projecting part beneath the notch bears about si
moderately strong spines and a few hairs.

I irri. First pair much shorter than and far removed from the second pair: seven

lents in the longer and six in the shorter ramus. The shape of the segments is nearly

quadrilateral, with the exception of the first segmenl which is of an elongated quadrangular form.

Nearly the whole surface of the segments is clothed with spines, which grow longer and stronger

towards the terminal segments. The second-sixth pair of cirri have both rami of equal length.

The segments are rather long and bear as a rule four or five pair of spines on the anterior

side and a tuft of small spines on the posterior near the junction of two segments. A few very

icate spincs are scattered over the surface of each segment.

Caudal appendages narrow, thin, more than half as long as the pedicels of the
sixth cirrus: a tuit of bristles, two or three of which are much longer than the others, is placed
on die summit; no bristles or one isolated bristle on the sides.

1' i-nis short, thick, terminating in a conical part bearing a tuft of extremely delicate
- at its extremity.

General remarks. This species shows a certain resemblance to /). Warwicki\ the

ever, being numerous and, so far as 1 could make out, constant, there can be

little doubt but that the) represent different species. As in D. Warwicki the scutum and tergum

ol y are different from the same valves in older specimens: the shape of these

23

valves in young specimens (üg. 2 a) comes near to that of the same parts in D. Hoekt as
figured by Stebbing. It is undoubtedly the most common form of Dichelaspis occurring in the
Malay Archipelago; it was collected during the cruise of H.M.S. "Siboga" at about 20 different
stations at depths varying from 9 to 112 m. They seem to be most numerous at depths not
exceeding 55 a 60 m. and are found attached to different objects: sterns and small branches
of horny corallines, algae etc.

The specimens from different localities and depths show considerable variety in their
general outline, size, shape of the valves, hairiness, the more or less complete calcification of
the valves etc. : no doubt the species would present a very valuable material for the study of
variation of a wild animal living under different conditions.

The following is a list of the stations where specimens of this species were collected.

Stat. 47. April 8 — 12, 1899. Bay of Bima (north coast of Sumbawa). Depth 55 m. Numerous

specimens attached, with Scalpellum rostratum Darwin, to different small sterns.
Stat. 60. April 27 — 28, 1899. Haingsisi, Samau Island, Timor. Depth 23 m. Numerous small

specimens.
Stat. 65". May 6, 1899. Lat. 7°o S., Long. I20°34'.5 E. Depth 120 m. at least; coral bottom.

One specimen.
Stat. 71. May 10 — June 7, 1899. Makassar and neighbourhood. Depth up to 32 m. 8 specimens.
Stat. jj. June 10, 1899. Lat. 3°27'S., Long. 117° 36' E. Depth 59 m. Fine grey coral sand.

One fairly large specimen.
Stat. 80. June 13, 1899. Lat. 2°2s'S., Long. U7°43'E. Depth from 50 — 40 m. Bottom: fine

coral sand. One large, three smaller specimens attached to a piece of coral.
Stat. 99. June 28 — 30, 1899. Lat. 6°?'. 5 N., Long. I20°2Ó'E. Depth from 16 — 23 m. Litho-

thamnion-bottom. 3 specimens, one attached to a small Lamellibranchiate Mollusc.
Stat. 125. July 18 — 19, 1899. Anchorage off Sawan, Siau Island. Depth 27 m. Bottom: stone

and some Lithothamnion. 3 specimens, with very short peduncles and very hairy.
Stat. 133. July 25 — 27, 1899. Anchorage off Lirung, Salibabu Island. Depth up to 36 m.

Bottom: mud and hard sand. 4 specimens.
Stat. 144. Aug. 7 — 9, 1899. Anchorage north of Salomakië (Damar) Island. Depth 45 m.

2 specimens.
Stat. 164. Aug. 20, 1899. Lat. i°42'.5 S., Long. 130° 47.5 E. Depth 32 m. Bottom: sand,

small stones and shells. Numerous small and larger specimens.
Stat. 172. Aug. 26 — 28, 1899. Gisser; anchorage betvveen this island and Ceram-Laut. Depth 18 m.

Coral- and Lithothamnion-bottom. A dozen specimens with perfectly calcified valves.
Stat. 213. Sept. 26 — Oct. 26, 1899. Saleyer anchorage and neighbourhood. Depth up to 36 m.

Extremely numerous specimens attached to threads of corals, to one another etc.
Stat. 257. Dec. 11, 1899. Kei Islands, Du-roa Strait. Depth to 52 m. Bottom: coral. 3 specimens.
Stat. 258. Dec. 12 — 16, 1899. Kei Islands, Tual anchorage. Depth 22 m. Bottom: Lithotham-
nion, sand and coral. Several specimens, some of them very large.
Stat. 274. Dec. 26, 1899. Lat. 5°28'.2S., Long. I34°53'.9E. Depth 57 m. Bottom: sand and

shells; stones. Numerous specimens, together with small barnacles [Balanus spec).
Stat. 282. January 15 — 17, 1900. Lat. 8°25'.2S., Long. i27°i8'.4E. Depth 27 — 54 m. Bottom:

sand, coral and Lithothamnion. Numerous specimens attached to polyps etc.
Stat. 289. Januari, 20, 1900. Lat. 9°o'.3S., Long. I26°24'.5E. Depth 112 m. Bottom: mud,

sand and shells. Two specimens.
Stat. 315. February 17 — 18, 1900. Anchorage East of Sailus Besar, Paternoster Islands. Depth
up to 36 m. Bottom: mud and sand. Three specimens.

I have pleasure in naming this beautiful and interesting species after Dr. H. F. Nierstrasz,
one of the Zoologists on board H. M. S. "Siboga".

23

- 1

-i' PI. II, fig I

ipitulum much compressed with the apex highly produced. Scuta with the l>asal segment
triangular and the occludent segment broad, having the shape • ■! > calpel; terga with the lower
about as wride as the occludent segment of the scuta; carina much bowed, terminating in
.1 disc, notched .n its extremity.

. neral appearance (PI. II. fig. ( apitulum compressed, flat. Valves nol very

close together. Valv< - thin and translucent, carina perfectly, other valves very imperfectly caleified.
meml ing the valves with rather long hairs.

rhe occludent segment is long, flat, pointed at its extremity; its
occludent margin is straight, the carina! margin convex, whence the shape <>i' tin- segment is
tliat calpel. The basal segment is triangular, small; only a small part <»i the valvi

i tches trom the lower point of the occludent segment t<> one fourth of its length;
might be called the junction of the two segments is caleified, but hm calcification is
in tli" basal segment itself.

I erga tfig. 10). Scutal margin excised at a point vis a vis the apex of the scutum;
the excision separates a smaller occludent projection trom a larger carinal projection or lower
part. < )ccludent margin simply and slightly curved. Incipient calcification ai the umbo, where
the valve shows an indistinct third prominence.

I arina (fig. i i . Much bowed, narrow, long. The basal end is rectangularly inflected

and stretches internally to about the half of the diameter of the peduncle. The whole valve is

caleified; the basal portion is slightly wider than the upper part and is excised ai its extremity.

Peduncle narrow. especially close under the capitulum; about "K the length of

the capitulum.

Si /e. Very small, the capitulum measuring not quite 2 mm. in length.
Mouth. Lal» rum bullate. Mandibles (fig. 12) with tour teeth and the inferior
angle tooth-like and acuminated. Maxillae (fig. 13), with three larger spines at the upper
angle, beneath which there is a triangular incision or notch, bearing two slender hairs. The
edge beneath this notch is straight and projecting, and hears six or seven unequal hut rat lo r
large spin<

t irri. First pair short with the rami very unequal: the longest lias five, the shortest
four segments; the segments are nearly quadrangular with the exception of the first which is
elongated; terminal segments sm;dl and blunt. Segments not thickly clothed with hairs or bristles;
these are placed somewhat irregularly.

The other cirri have ver) long and slender segments, bearing three pairs of spines
i ruk-.

The caudal appendages are extremely slender hut not longer than half the length

ot tl !^ of the sixth cirrus. They bear a few (about four) very delicate hairs at theirends.

Th' ecimens are attached to long. yellowish-brown hairs or spines, which are hollow

angular pointed teeth placed in irregular rows. They wen- taken, October 1899,

orage, at a depth of 10 — 25 m.

-1

Remarks. I am not quite sure that the specimens I have examined represent the
full-grown form. Yet the shape of the valves and of the capitulum as a whole are so characteristic
that it may be described as a distinct animal. In some regards it approaches D. Warwicki — ■
but the much produced form of the capitulum makes it at once look very different, the shape
of the scutum being moreover very peculiar.

The species is named in compliment to Captain now Commander G. F. Tydeman, the
distinguished commander of H. M. S. "Siboga" during its cruise in the Malay Archipelago.

3. Dichelaspis orthogonia Darwin. PI. II, fig. 14 — 18. PI. III, fig. 1, iA, iB and \ob.
185 1. DARWIN, Monograph, Lepadidae, p. 130, pi. II, fig. 10.

Since Darwin published his Monograph, this species has not been observed so far as
I know. Darwin described it from British Museum specimens, habitat unknown. The "Siboga"
collected a few specimens, south of Timor, at a depth of 112 m., and again at two other
stations, 80 and yy, in the Archipelago: I think it very probable that the specimens studied
by Darwin had also been collected in the Malay archipelago.

I had at my disposal a few large and smaller specimens of this species. The largest
has been drawn by me, magnified about 10 times, and is figured PI. II, fig. 14. The capitulum
of this specimen measures 6,6 mm., whereas Darwin says that the length of the capitulum is
above 2/i0ths °f an inch, 5,1 mm. The other specimens of the "Siboga" are about that size, or
still smaller.

The shape of the valves is much like Darwin's description : I have prepared these valves
from a 5 mm. specimen and figured them separately (fig. 15, «, ó, e).

The scutum (fig. 15a) corresponds well with Darwin's description; in the largest
specimen however, the occludent segment is less than twice as long as the basal segment.

The ter gum (fig. 1 5 <5) shows the four prominences in which the four ridges proceeding
from the umbo end. The projection at the occludent margin of the valve is extremely small,
smaller perhaps than in the figure given by Darwin.

The carina (fig. 15c and fig. 16) terminates in a heart-shaped disc (fig. 16) with a
slight excavation in the middle. This excavation in the specimen the valves of which I prepared
was neither so deep nor so distinct as Darwin has it in his description. The whole shape of
the valve, however, so much resembles D.'s description and figures, that no uncertainty as to
its identity could remain.

Darwin's specimens were in a bad condition ; of the peduncle he said that it was
unknown, probably short. The "Siboga" specimens all have a peduncle: it is cylindrical and
has about one third the length of the capitulum.

The different parts of the mouth correspond well with Darwin's description. I give a
figure of the maxilla (fig. 17) showing the notch (bearing one spine) beneath the three large, upper,
unequal spines, and the highly projecting inferior part bearing eight spines in all, one of which
(the third) is larger than the other ones. Darwin says that this inferior part is, itself, obscurely
divided into two steps — the maxillae of the specimen I dissected did not show this peculiaritv.

25

SIBOOA-EXPEDITIE XXXI cl. 4

ï6

I imens in all were taken; some of them were attached to cylindrical sterns of

ralline organism most probably. The length of the capitulum of the largest pecimen taken

that "i its peduncle is about 1,6 mm. A young specimen is
near it nity.

rhe •Siboga" i . »< .k these specimens at three different Stations:

Lat. 3 -,~ S., Long. u; 56 E. Depth 59 m. Bottom: fine
ind. 1 specimen,
me 13, 1 Borneo Bank. Depth 50 — 40 m. Bottom: fine coral-sand. 1 specimen.

.. Januai [900. Lat. 9 0.3S., Long. 126 24'. 5 1 . Depth [12 m. Bottom: mud,

nd and sliclls. 3 specimens.

1 ormae dubiae. Though 1 have long heen in doubt on the matter, 1 consider a

two large, two smaller and a few very small specimens) as belonging also to

this sj which were collected bj IL M.S. "Siboga" at Station 318 at a depth of 88 m.,

two small specimens taken at Station 294. Their shape is slightly different, being much
flatter and the peduncle is shorter. The largest specimen has a capitulum over 7 mm. long
and may be considered a full-grown specimen as it is furnished with well-developed egg-sacks.
This anima! is figured on PI. II, tig. 18. In this specimen the proportion ut' the two segments
of the scutum is different from what it is in the individual represented in tig. 14 of the same
plate. Other ditïerences are shown by the figures anti are perhaps not important enough tor
minute description. Of one of the specimens of Station 318 I have prepared the valves and
made with their aid the drawing tig. 1, PI. III. I have made a drawing further of the smallest
specimen of all (PI. III. tig. 1 A), taken also at Station 318 and of one of the slightly larger
"in-s (PI. III. tig. 1 II cf Station 294. In that of Station 318 the shape of the shells is still
(piite different from that in the full-grown and those of Station 294, having a capitulum of
t,8 mm. in length, may be considered as forming the transition between the very small one
with a capitulum of 1,25 mm. and the full-grown form.

The position of the stations where these forms were taken was as follows: •

14. January 23, 1000. Lat. to°i2'.2S., Long. 1 24 : 27 .3 I-".. Depth 73 m. Bottom: soft
mud with very fine sand. Two small specimens.
St.it. 318. Fcbiu.it v 22, 1900. Lat. 6°3o.5S., Long. [I4°55'.5E. Depth 88 m. Bottom: fine
yellowish grey mud. Several large and smaller specimens.

4. Dichelaspis Weberi n. sp. PI. III, tig. 2 — 7.

Capitulum much compressed with the apex slightly produced. Scuta with the basal segment
.ver than the occludent segment and not quite half as long. Terga with three unequal
ma projections on the scutal margin of the valve. Carina much bowed, internally very

rminating downwards in a small spatula-like disc.

ral appearance. Capitulum compressed, flat. Valves relatively small, narrow, a
tween the carina and the other valves. Valves covered by a thin transparent
ily Peduncle cylindrical, much shorter than the capitulum (PI. III, tig. 2).

26

27

S cu turn (hg. 3 a) consisting of two bars placed at right angles to each other, with the
point of junction fully as wide as any part of the basal segment and perfectly calcified. The
basal segment slightly tapering to the carinal extremity, the occludent segment widening
considerably to the apex, which is obliquely truncated. The length of the occludent segment
is slightly more than twice that of the basal segment.

Ter gum (fig. t,ó) of a triangular shape, with three ridges, terminating in three promi-
nences of unequal length. The longest forms the basal point; of the two others that at the
occludent margin is the shortest. In the angle between the latter two prominences the apex of
the scutum in younger specimens fits exactly. In older specimens, like that figured in fio-. 2,
there is a distinct interspace between the apex of the scutum and the tergum. The valve is
rounded at the umbo and shows a tracé of a fourth prominence on the carinal margin just
above the apex of the carina.

Carina (fig. $c and 4). Much bowed, rather narrow, long; externally the central ridge
is flattened towards the apex; internally the valve is concave, the concavity nearly reaching
to the disc-like basal portion. The width of the carina remains almost the same over its
whole length, with the exception of the basal portion which widens and forms a spatula, as
figured in fig. 4.

Peduncle short, cylindrical, one third the length of the capitulum at most.

Size. The capitulum, in the largest specimen, is more than 10 mm. when measured
along the occludent margin and about 1 2 mm. when measured from the apex of the terooim
to the base of the carina. It is the largest of the known species of the genus.

Mouth. Lab rum with the upper part bullate as in the other species of the genus;
crest with a row of small triangular teeth. Palpi smail, conical, moderately clothed with bristles.

Mandibles (fig. 5). Much like those of the other species of the genus: rather
narrow, distance between the tips of the first and seconcl teeth slightly shorter than that
between the second tooth and the inferior angle. The inferior angle produced into an indistinct
doublé spine.

M a x i 1 1 a e (fig. 6). Three large upper unequal spines and a fourth delicate one attached
to the base of the third. Notch neither very wide nor very distinct, bearing two pairs of slender
spines and a much stronger one half way to the beginning of the projecting inferior part. The
latter bears nine or ten spines of unequal length and strength.

Ou ter max-illae (fig. 7) rather broad, general shape rounded-quadrangular. Covered
with longf bristles which moreover form a dense tuft all over the outer margin.

Cirri. First cirrus separated by a wide interval from the second pair; short, with the
two rami unequal in length, though both consisting of seven segments. The segments are broad,
quadrangular and thickly paved with long and slender spines. The other cirri have very long
rami as well as pedicels.

Ca u dal appendages small and narrow with a few long spines at their ends.

H. M. S. "Siboga" took this fine species at:

Stat. 262. December 18, 1899. Lat. 5°53'.8S., Long. i32°48'.S E. Depth 560 m. Bottom: solid
bluish-grey mud, upper layer softer and brown mud. In all 9 specimens.

27

I naV( in naming this fine and characteristic deep-sea species after the

tpedition, Profcj Max Weber. 1i was taken at .1 depth of 560 m.,

and thu 'ered a d< species.

I( it shows a certain resemblance to />. orthogonia and belongs

: • nus, luit it differs (rom it by its size, as well as by the shape

and of the disc forming the base of the carina.

:n species and />. sesst/ts Hoek, dredged l>\ the " Challenger" in the Atlanl
. .it a depth ui fathoms, are the only known species ol the genus Dichelaspis

livinj depths.

ispis Versluysi n. sp. PI. 111, fig. 8 — [3.

ipitulum compressed, apex produced. Scuta with the basal segment much narrower
than the occludent segment and more than half as long. Terga with three distinct marginal

•:is and a fourth one very small. Carina terminating downwards in an oval disc-like cup.

Genera] appearance. Capitulum llat: valves small, a large part of the surface of
the capitulum remaining uncovered. Valves covered by membrane so as not t" beseen distinctly
without isolating them. Peduncle cylindrical not quite half the length of the capitulum (PI. III. fig. 8).

S ntuni (fig. o*?'. It consists of two bars placed in most oi' the specimens at right
angles to each other, in one of the specimens (figurcd in fig. 9) at an angle of more than 900.
The point of junction is perfectly calcified. The basal segment uniformly narrow, the occludent
segment, which is less than twice as long as the basal segment, grows much wider towards
the apex. It is flat with the apex obliquely truncated.

1 ergum (fig. tjó) of a triangular shape, with three ridges terminating in three
prominences of unequal length. Seen from the outer side the three divisions are separated from
one another by distinct. even deep furrows. The fourth ridge or prominence is extremely small
and situated at the carinal side just above the apex of the carina.

1 tri na (fig. <i(- . Much bowed, even slightly more than is the case in D. W'c/'cri.
long. not very narrow, keel-shaped in its basal part and with a flattened central ridge above
the middle to as far as the apex. Internally the valve is concave. The basal portion is embed
and forms a cup of a verj peculiar shape: it is oval with at each side a small wing, like the
small handles of a bowl PI. II, fig. 10a, while fig. 10/; shows the cup-shaped basal portion
of a specimen of D, orthogonia with the same enlargement, seen from the same side).

Peduncle short, cylindrical-, length about one third that of the capitulum. In most of the
■neus the chitinous outer wall is transparent and surrounds the muscular part like a wide sack.

Size. Length of the capitulum in one of the larger specimens 6,3 mm. when measured
from the tip of the tergum to the base of the carina. Several specimens, however, are considerably
I';. largest specimen is over ~ mm.

The mouth and its parts in genera! resemble greatly the same paris in /). orthogonia:
labrum with a row of small bead-like teeth; palpi with the two sides parallel,
• one side numerous very long bristles.

29

Mandibles (fig. i i, a, b and c) narrow with four teeth and the inferior angle produced
either in a single tooth or in two smaller teeth : in two specimens the right mandible had the
inferior angle terminating in two, the left in one larger tooth.

Maxillae having the three larger upper unequal spines and the notch beneath these
as in D. orthogonia. In the notch two delicate spines are planted as a rule and the inferior
slightly projecting part is indistinctly divided into an upper step with three and an under step
with five or six spines. (In fig. 12 of PI. III one of the maxilla of a specimen of this species
is represented with only two large upper spines; the other maxilla of the same specimen had
the normal number of three spines above the notch).

Outer maxillae, outline semi-elliptical rather than hemispherical ; not sparingly
covered with bristles. The longest bristles are planted near the middle of the outer margin
of the maxilla.

Cirri. Pedicels and rami of the five posterior pairs are very long; segments much
elongated, each bearing four pairs of very long spines and a fifth pair much shorter. Between
each pair there is an excessively minute spine — as described by Darwin for D. orthogonia.

( )f the first pair, which is separated by an interval from the second pair, both rami are
short and only slightly unequal in length ; the number of segments is 6 in the shortest and 7
in the longest ramus. Both are paved moderately thickly with spines as in D. orthogonia.

Caudal appendages long and narrow, distinctly two jointed, with a number of long
hairs or delicate spines at their ends and a few hairs planted here and there (PI. III, fig. 13).

Penis short, thick ; terminating in a narrower and curved part bearing a tuft of very
delicate hairs.

This species was taken at :

Stat. 164. August 20, 1899. Lat. i°42'.5 S., Long. i30°47'.5E. Depth 32 m. Bottom: sand,
small stones and shells. About 12 specimens.

General Remarks. I have some doubt as to whether I ara risdit in consideringr this
as a species ; but as there are full-grown specimens with eggdamellae in the collection and as
these difter in the shape of the valves from D. orthogonia, to which this form in other regards
shows great resemblance, I have thought it useful to give a description of it and to consider
it as a separate species. I have the impression that several species in this genus have rather
fiuctuating characters, but it is quite impossible to make out how far the variation or the
fluctuation of these characters goes without a very large material of specimens from the same
locality as well as from different places.

The species is named after Dr. J. Versluys, one of the Zoologists of the scientific staff
of H. M. S. "Siboga".

Forma dubia. I have figured on PI. III (in fig. 14) another form of Dichelaspis,
which is represented by one specimen only. It belongs, no doubt, to the same group of species
as D. orthogonia, Weberi and Versluysi and it shows in many regards great resemblance to
D. Versluysi in particular: it has almost the same form - but, as it is at the same time

29

mportant details, I consider it as .1 variet) of the last described

apitulum wi : li.it the occludent segmeni ol the scutum of this

,!,,,„ t> ■ the basal segment, and thal il does n<.i grow wider

i.ui has about the satne width throughout its length. I h<- tergum of this

furrowed like the same valves in D. Versluysi, does not show the

just above the apex of th<- carina. The carina itself not only lias almost

ral shape, biil its basal portion ha il\ the particular form which is so

•

resents this form and this specimen, the length of the capitulum

mm., has been dissected to prepare the valves and to make out its identity:

t this form no longer exists and this alone would 1"- a reason for not

it into science as ,1 new species. As, further, its relation to />. Versluysi is ver)

1 think it right t<> indicate it as D. Versluysi Var. The single specimen was taken at:

258. 1 'cc. 12— ï". [899. Tual anchorage, Kei Islands. Depth 22 111. Bottom: Lithotham-
nion, sand and coral.

Genus Megalasma Hoek
HOEK, Cirripedia of the "Challenger", 1883, p. 50.

This genus was founded (1883) for a very characteristic Cirriped dredged during the
cruise of the "Challenger". It belongs to the same natural group of genera as Poecilasma,
Dichelaspis and Lepas and is nearly related to the first of these tliree.

In [894 W11 i\i.k' described a second species of this genus and gave it the name of
M. carino-dentatum. A third was collected by Il.M.S. "Siboga" in 1899.

The diagnosis given for this genus in the "Challenger" Report holds good for the forms

•vered later, with one exception; the triangular form of the scutum which was so very

striking in M. striatum is, strictly speaking, gone in -JA lineatum (and so far as can be judged

from the sketches of Weltner, the same is the case in M. carino-dentatum), there being a

distinct though short basal margin. Hence, I propose to have the diagnosis changed so far that

ta are not called triangular but approaching more or less to a triangular form.

For the determination of the species known at present, the following table may be of use:

Megalasma

.1. Dorsal margin of the carina developed into a broad flattened part
forming the continuation of the downwards inclined portions of the

mg their carina! margin IA striatum.

margin of the carina not forming a broad flattened part.

margin of the carina having a tooth-like excrescence. . .IA carino-dentatum.
al margin of the carina without a tooth-like excrescence. . M. lineatum.

m Indischen Ocean. Sit/. Ber. <',L-~. Naturf. Freunde zu Berlin, 1S94, p. So.
3°

3i

M. striaUtm which was taken by the "Challenger" in the Philippine Archipelago at
depths of 180 and 207 m. was collected by H. M. S. "Siboga" at different places in the Malay
Archipelago at depths from 204 to 984 m. M. carino-dentatitm was found on the stem of a
Hyalonema from the Gulf of Bengal, dredged at 3200 m. M. lineatum was dredged in the
Malay Archipelago from a depth of 450 m. So all the species may be considered as deep-sea
forms, the range of depth over which they spread being very large. Hitherto, the p-enus has
only been found in Asiatic Indian Waters.

1. Megalasma striatum Hoek.

1883. HOEK, Cirripedia of the "Challenger". p. 51, pi. II, fig. 5 — 9, pi. VII, fig. 8 — 9.

The "Challenger" collected this beautiful species in the Philippine Archipelago at a
depth of 100 a 115 fathoms, about 180 a 207 meters, in November 1874.

It has not been observed, so far as I know, from that date until H. M. S. "Siboga"
dredged some specimens in 1899 at different stations, viz.

Stat. 251. December 8, 1899. Lat. 5°28'.4S., Long. i32°o'.2E. Depth 204 m. Bottom: hard

coral sand. Numerous specimens attached to the spines of an Echinus. The largest

specimen measures 10,5 mm.
Stat. 253. December 10, 1899. Lat. 5°48'.2S., Long. I32°I3'E. Depth 304 m. Bottom: grey

clay, hard and crumbly. One small specimen attached to the spine of an Echinus.
Stat. 267. December 20, 1899. Lat. 50 54' S., Long. I32°5Ó'.7E. Depth 984 m. Bottom: grey

mud with a brown upper layer. One specimen attached to the silicious skeleton

of a sponge.

The range of depth of this species is now found to be much greater than could be
judged from the results of the Challenger: we are now permitted to say that this species is
one of those capable of existing at a considerable variety of depth.

At the same Stations where this species was collected, other Cirripedia were also brought
up with the dredge; thus, at Station 251 : two species of Poecilasma, four species of Scalpellum,
one of Balanus etc.; at Station 253: three species of Poecilasma etc. The conditions must be
particularly favourable for the development of Cirripedia at these Stations ! With reference to
this, see my Report on the Cirripedia of the "Challenger", p. 25.

2. Megalasma lineatum n. sp. PI. IV, fig. 1 — 8.

" Scutum with the carinal margin bowed, considerably longer than the straight tergal margin
and with a distinct though short basal margin. Tergum triangular, small. Carina with the lower
end truncate and very wide, the upper end narrow and elongated. Peduncle extremely short.

General appearance. PI. IV, fig. 1 and 2. Capitulum elongated, about twice as long
as broad, swollen in the middle. The short peduncle extends from underneath the capitulum.
The short basal margin of the scutum forms the continuation of the truncate basal margin of
the carina. The valves are delicately striated ; strips of membrane run over the lines separating
the valves.

Scutum (fig. 1 and 3a) elongated, not exactly triangular, there being a short basal

31

,, the imen is more distincl tlian in the smaller. The carinal margin

the tergal margin; where these margins meel an obtuse angle is

.1 ii"t ver) prominenl ridge runs to the occludent margin. This

the outer surface <>i' the scutum. Internally ;i m <i ver) prominent ridge

ver half of the occludent margin, whereas ;t much more prominent and bowed

imall basal portion from the rest of the valve. Where these t\\i> ridges meet,

ludent margin, .1 relatively strong tooth having the shape of a linie nail, is formed.

rergum fig, i and ;,/' triangular, relatively small. Carinal margin and scutal margin

iame Iength; the former does not show the flattened border which is so

for 1/ striatum.

fig. 2, ie and .) broad towards its basal end, much bowed, terminating
in a narrow fiat part which runs up to the basal ends of the terga. The flattened
il margin is narrow and has about the same breadth throughout its Iength. The lias.- is
abruptly truncated. The scutal margin at one third of its Iength from the base shows a smal!
tooth or exi ce which fits into an indistinct excavation in the carinal margin of the scutum.

This detail of the structure seems more stronglj developed in younger specimens it cannot
at any rate be made out so sharply in full-grown specimens without isolating the val.
Peduncle very short, slightly extending from underneath the capitulum.
Size. The largest specimen has a capitulum of ï cm. in Iength.

Mouth. Labrum (fig. 5) bullate; crest with a row of numerous : ' 40) small triangular
. 1'alps small. hairs numerous at the tip and along the interior margin.

Mandibles fig. 6 with tour teeth, the interior angle terminating in a single delicate
spine. The distance between the tips of the first and second teeth one and a half times as
great as that between the tips of the second and third.

Maxi 11 ae (fig. 7 with three spines at the upper angle, the notch beneath the upper
spines relatively large and the inferior raised part rather narrow. There are three delicate hairs
or spines planted in the notch, and about ten larger ones on the part beneath the notch.

Outer maxillae of a quadrangular shape with rounded edges. Numerous, delicate
hairs planted on the outer surface, the largest along the outer margin.

1 irri. First pair t'ar removed from the second pair with very short rami. Rami not SO
much differing in thickness, much more so in Iength. The longest ramus has ten, the shortest
nine segments. Spines planted over a great part of the surface of each segment. The second
cirrus has about the same shape and structure as those following : each ramus consists of long
and narrow segments; two stronger and a third much more delicate spine are planted at the
convex side near the extremity of each segment; the concave side having as a rule three
stronger pairs of spines and a fourth very delicate pair. An extremely delicate spine is inserted
in the angle formed by each pair of stronger spines.

tudal appendages fig. 8). Very short, terminating abruptly and broad, and
• very large number of fairly strong hairs at its truncated extremity.
Penis in the specimen that was dissected broken off; the part attached to the body
cylindrical with hairs here and there.

32

33

This species was taken at :

Stat. 74. Tune 8, 1899. Lat. 50 3'-5 S., Long. 119° o' E. Depth 450 m. Bottom: Globigerina ooze
(obviously a thin layer). Two specimens, which, according to the label, were
attached to a spine of Goniocidaris florigera.

General Rem ark s. Long after the above description was written, I found in Annandale's
"Preliminary Report on the Indian stalked Barnacles" (published April 1906) \ that a form of
Megalasma occurs in the Andaman Sea at a depth of 290 — 775 m. which "aorees in even-
respect with Hoek's striatum from the Philippines, except that the semicircular ridge on the
lower part of the capitulum, which forms a conspicuous feature in the latter, is quite absent".
Annandale has called this form a subspecies [M. striatum, subsp. minus nov.), not a variety,
"because it seems to represent a well-defined local race, differing only slightly from the typical
form, but with a constant difference".

This is the only information at hand regarding this " subspecies" — 110 figure is o-iven.
I would not be astonished, however, if this form and my new species M. liucatum proved to
be identical s.

Genus Alepas Sander Rang

Darwin (185 1) enumerated four species of the genus Alepas: two of these he saw and
investigated himself {A. minuta Philippi and A. cornuta Darwin), the two others [A. parasita
Sander Rang and A. tuöulosa Quoy et Gaim.) were known to him only from figures and
descriptions published by Quoy & Gaimard, Sander Rang and Lesson. The "Challenger" collected
a fifth species of this genus which was described by me in 1883 as A. pedunculata. Six other
species have since then been added to the list, viz. two by Aurivillius3 (A. quadrata and
A. japonicd) and four by Gruvel * (A. Belli, A. indica, A. microstoma and A. Lankesteri).
The latter author in his "Monographie" (1905), p. 164, has given a synoptical table for the
determination of the 1 1 species of this genus known to him.

Since then, Annandale 5 has described three more species of this genus, viz. two (1905):
A. gigas collected in Bali Straits and A. malaysiana dredged in Gaspar Straits, and one (1906):
A. xenophorae found off the S. W. coast of (English) India.

To this number of 14 species come those dredged by the "Siboga" on different occasions
in the Malay Archipelago. They represent in all five different forms, which I think must all
be considered as new species. Two of the new forms are however represented by one specimen
only and as it is impossible to describe these without dissection, I shall only give a figure with
a short description of the outward shape : they have been named A. ovalis (taken YV. from
the Key Islands at a depth of 984 m.) and A. tennis (S. of Ceram at 204 m. depth).

The other three new species are represented by numerous specimens. I propose to name

1 Annals and Magazine of Natural History. (7), XVII, April 1906, p. 399.

2 A good figure is given in the "Illustrations of the Zoology of the R. I. M. S. S. Investigator" Calcutta, 1907. Annandale's
subspecies and my new species are identical. (Note added duiing press).

3 Aurivillius, C. W., Studiën über Cirripedien. K. Svensk. Vetensk.-Akad. Handl. XXVI, N° 7, 1894, p. 28—32.

4 Gruvel. A., Sur quelques Lépadides nouveaux de la collection du British Museum Trans. Linn. Soc. VIII, 8, London, 1902.

5 Annandale, X., Malaysian Barnacles in the Indian Museum. Memoirs of the Asiatic Society of Bengal. I, 1905, p. So — Si.
Preliminary Report on the Indian Stalked Barnacles. Ann. and Mag. Nat. Hist. (7), XVII, April 1906, p. 399.

33

SIBOGA-EXPEDITIE XXXI a. 5

them .in.l ./ lithotryae. The fust was collected between Borneo

and Lomb i depdi m., the id N.W. from the Key Islands at po m. depth,

the third n a Island at .1 depth of 894 m. attached to the valves ol Lithotrya

h.is, not unlike ./. quadrata Auriv., horny, nearly quite hidden

i ;u once by the ver) peculiar structure of the capitulum;

far .is the structure i»l" the 5'11 and 6°" cirrus is concerned between

the with quite normal rami and those in which the inner ramus is quite rudimentary.

Including the from the "Siboga" we now have ig species of Alepas in all.

parts or valves which facilitate the separation of the species in other

1 lakes ihis distinction a troublesome one in Alepas. The ontward

apitulum, the length and proportions of the peduncle are liable to change with

. under the influence of the fluid used for the conservation etc. The question whether

all ti ribed are really good species in the case of Alepas is more difHcult to answer

than for the other genera. Yet, considering the circumstances under which they were taken

rent objects or animals to which they were found attached. different depths, geograph
distribution) there can l>e no doubt, I think, but that most of the species are really different forms.
The following table enumerates all the species at present known, arranged accordin^ to
their bathymetric occurrence with indication of their geographical distribution. The species found
in the Malay Archipelago are marked with an asterisk.

Alepas Lankesteri Gruvel. 1465 m. Mona Channel, West Indies.

epas ovalis n. sp. 984 m. \Y. from the Key Islands.
Alepas pcdiiiicitlala Hoek. 740 m. Ott New South Wales.

pas morula n. sp. 538 m. Between Borneo and Lombok.
Alepas minuta Philippi. 355 — 250 — 100 m. Mediterranean, Atlantic ( 'cean.
Alepas xenophorae Annandale. 333 m. S. W. Coast of (English) India.
ras Annandale. 290 m. Bali Straks.
pas tennis n. sp. 204 m. South of Ceram.
'Al pas inter media n. sp. 90 m. N.W. from Key Islands.
Alepas japonica Aurivillius. 80 m. Japan Sea, Hirado Street.
'Alipas malaysiana Annandale. 55 m. Gaspar Straits.

epas lithotryae n. sp. Reef. Near South Lucipara Island.
AUpas tubulosa Quöy <!v Gaimard. On Palinurus ('Coast'-). New Zealand.
*AUpas quadrata Aurivillius. On Palinurus (Coast?). Thousand Islands Java).
Alepas cornuta Darwin. ? West Indies: St. Vincent.

Alepas parasita Sander Rang. Surface (on Medusae). Mediterranean, Atlantic Ocean.
Alepa Belli Gruvel. ? Cuba.

Alepas microstoma Gruvel. "'Madeira.

f indica Gruvel. Surface (on floating wood). Singapore and Nicobars.

that of the [9 species described in the literature 9 or about the half have
I in the Malay Archipelago; in this region, the genus may indeed be called prolific.

34

35

As most of the species of this genus — with but very few exceptions - - have been
observed only once as yet, no conclusions can be drawn with regard to the bathymetric range
in relation to the geographical distribution.

i. Alepas morula n. sp. PI. IV, fig. 9 — 12.

Capitulum globular, its surface with numerous tubercles. No scuta. Orifice small, not
protuberant. Peduncle more than half as long as the capitulum. Inner rami of the 5Ul and 6th
cirrus as strongly developed as the outer rami.

Capitulum (PI. IV, fig. 9) globular, with the carinal edge somewhat projecting like a
crest, entirely destitute of valves, but with the thick chitinous envelope showing large tubercles
all over its surface, giving the animal a certain resemblance to the fruit of the mulberry. The
colour of the specimens conserved in alcohol is a greyish yellow, the peduncle being brownish.
Indistinct brown or reddish transverse lines run over the surface of the capitulum. Orifice small,
hardly protuberant, its edges sinuous.

Peduncle rather long, narrower than the capitulum, into which it insensibly blends ;
its surface very uneven, partly from being wrinkled, partly in consequence of the chitinous
envelope bearing tubercles, which are however smaller than those of the capitulum. Surface of
attachment not very wide.

Size. The length of the capitulum and the peduncle together is 10,5 mm. in one of the
larger specimens, the capitulum alone measuring 6,5, the peduncle 4 mm.

Mouth. The labrum (fig. 10) has on its free margin a continuous row of 24 short,
strong and blunt chitinous teeth. This row of teeth describes an arch, 14 of the teeth form
the midclle part and 5 are planted on each side. Numerous minute hairs or bristles are scattered
over the teeth, larger and stronger hairs outside the teeth, especially beyond the attachment
of the palpi.

The palpi are triangular, elongated. Their tips are at considerable distances from each
other : even the bristles planted at the extremity do not touch each other. These bristles are
strong and doubly serrated.

The m a n d i b 1 e s (fig. 1 1 and 1 1 a) have three teeth and the inferior angle, which
by some authors is considered a fourth tooth, ends in the specimen I dissected in a single
sharp spine at the right side (fig. na), in two distinct teeth at the 'left side (fig. 11). First
tooth not so far from the second as the latter is from the inferior angle. The second and third
teeth pectinated.

The maxillae (fig. 12) have a notch beneath the three upper spines. Of these one is
considerably larger than the other two. In the notch are several spines, three or four of which
are strongfer than the others. The edge beneath the notch bears numerous strongf and smaller
spines and is indistinctly divided into two steps.

Outer maxillae quadrangular with rounded edges ; a dense tuft of serrated bristles
is directed towards the mouth opening, a less dense group of smooth hairs or bristles is directed
towards the base of the maxillae.

35

rri long, with short and numerous segments, with the exception ol those of the lirst
|).iir which are rather short aiul braad.

First cirrus placed far from the second; its pedicel is relatively Ion rami short,

slighdy unequal, the longest has also the broadest segments; both rami have eight segments,
the ing very minute. rhe segments on both rami bear strong bristles placed in a row

near the anterior extremit) of each ■"-ment Mie segments of the strongest ramus have further
a dense clothing of bristles i>n the side which is directed towards the more slender ramus.
Whereas the smal! terminal segment of the more slender ramus bears three str< nies, the

same segment of the stronger ramus lias one slender spine only; further a number of extremely
small hairs are placed at iis extremity. In the ruw of bristles al the extremity of the sixth and
intnts of the stronger ramus two or three bristles are wanting; minute scales are
■ ■ ut at the places left open. Beneath the 1ms.i1 articulation of the irrus a long filamentary

appendage is situated.

nd to sixth cirrus much resembling each other, their length and the number
of the segments slightly increasing from the second to the sixth; in the second each ramus has
i 3 a 14, in the sixth r6 a 17 segments. The pedicels and the lowermost segments of the rami
of the second and third cirri are much more densely clothed with hairs than the same parts
of the fourth — sixth cirri. As a rule each segment of each ramus bears a row of bristles near
ctremity, two very strong bristles on the dorsal face of each segment near the articulation
of the following segment and a group of bristles on the ventral face, also near the extremitv of

ment. The ventral face of most segments shows a row of very short stiff hairs. giving
it the appearance of being serrated.

The rami <>f the 5th and 6lh cirri are slightly unequal; the outer ramus has 17, the
inner only 15 segments.

Caudal appendages long, reaching as far as the end of the fifth segment of the
rami of the sixth cirrus. composed of 14 very slender segments each with a number of very
delicate bristles or hairs on its summit.

Penis indistinctly ringed or segmented, tapering towards the extremity; numerous delicate
hairs - I over its surface and a dense tuft of slightly stronger hairs at its extremity.

One ol the specimens I investigated was furnished with eggs which were united in one

mass. The eggs were extremely numerous and very small. Most of them contained Nauplii

and many seemed to have come out before the animal was caught and put into the preserving

tluid. The form of the eggs was long-oval, their length was 0,3, the greatest breadth o,i 5 mm.

Larvae without eyes or without black pigment in the eyes.

This species was taken at :

Stat. 316. February 19, 1900. Lat. 7 [9.4 S., Long. 11649. 5 E. Depth 538 m. Bottom; fine,
dark brown sandy mud.

The specimens were found attached to the spines of Porocidaris elegans, a sea-urchin
which was caught with the trawl. There are in all a dozen large and about as many smaller
1 'tien one or two large and a few smaller specimens form a group, being attached
iother to tin- same spine.

36

•>7
2. Alepas intermedia n. sp. PI. IV, fig. 13 — 16.

Capitulum oval, surface smooth, 110 scuta. Orifice narrow, not projecting. Peduncle stout,
nearly as long as the capitulum. Inner rami of the 5th and 6th cirri slightly shorter than the
outer rami.

Capitulum of an oval shape (fig. 13), apex bluntly pointed, carinal margin strongly
bowed, rostral margin also bowed but less strongly. Orifice a narrow slit, which from being
exactly in the longitudinal axis is hardly visible, when the animal is seen laterally. The capitulum
is entirely devoid of scales or valves; its surface is smooth, one or more indistinct furrows
excepted, which start from the rostral edge and describe curves over the surface. The capitulum
blends insensibly into the long and strongly developed peduncle, the surface of which is either
nearly quite smooth, or indistinctly ringed transversely.

The peduncle is somewhat compressed laterally : the shape of a transverse section is
oval, not circular.

S i z e. The figure 1 3 represents one of the larger specimens. It has a capitulum about
1 cm. and a peduncle about o,S cm. long.

The body and its appendages are in general as in the other species of the genus. I wish
to point out only the following characteristic features.

Mout h. Of the labrum (fig. 14) not only the middle part of the crest is furnished
with a row of teeth, but also each lateral part. Those of the middle part are blunt, shorter in
the middle than at the sides, whereas those of the lateral parts are sharp, hook-like. The middle
part has about 20 teeth, each lateral part 8 — 10.

The p a 1 p i are perhaps not quite so long and narrow as in the other species of the
genus ; they have a dense row of rather long and strong bristles on the outer border and these
bristles are doubly serrated.

The mandibles (fig. 15) have three teeth and the inferior angle. The latter ends in
a single sharp spine. The distance between the first and second teeth corresponds exactly with
that between the spine of the inferior angle and the second tooth. The lower edges of the
first, second and third teeth of the mandible appear pectinated, owing to the presence of short
strong spines projecting from the sides of the teeth.

The m a x i 1 1 a e (fig. 1 6) have a triangular shape, with the edge rather long ; the notch
beneath the three larger upper spines and two other shallow notches about the middle of the
edge give it an irregular appearance. The spines are very unequal in strength and size : a few
are large and strong, the smaller ones are more numerous. The apodeme is rather long.

The outer maxillae are square in shape, broad with the angles rounded. The bristles
form thee distinct groups: some rather long are planted round the free outline and cover the
superior part of the dorsal face of the maxilla. A second group consists of short and rather
stiff bristles planted close to the margin at which the two maxillae touch one another. The
bristles on the basal part of the maxilla are long and delicate and form a third and much less
dense group near the so-called olfactory orifice.

The cirri are but slightly curled; though the pedicels are rather long the shortness

37

3Ö

of the rami 1 1 1 « - whole cirrus to be short. The firsl pair is placed near the mouth and

ome di the second. lts r.imi are nearl) equal and composed ol five segments

only. The ent is very long, longer than the other four segments together ;m«l nol

iposed "i four <t five short and broad segments solden ether. Segments

. very characteristic péntagonal shape, segment 5 is short, small, quadrangular.

horter ramus is at the same time ;i little narrower. It can be said t<> have one

nent more than the longer ramus, as the last segment of those which are soldered together

form the 1 ment <>l" the longer ramus lias remained free in the shorter one. Each

irs .1 broad group of long bristles on iis outer surface; the first segment show

such groups of bristles. The last segment lias the bristles planted close i<> its extremity.

< >n the inner surface the bristles are less numerous and nol placed so regularly, on tin- outer

lents they form a row near the extremity. Along the dorsal margin, «ach segment bears

a long bristle planted slightly above the middle of its length.

The pedicel of the lirst cirrus is much shorter than that of the other cirri. The filamentary
3 si ated beneath the basal articulation of the lirst cirrus; it is long, conical and
nted at its extremity.

The 2nd cirrus lias ten segments in both rami, the 3rd 11 in the shorter and 13 in the

er ramus ; the 4!h lias [2 and 13 segments, the 5th and 6th 1; and 15 — at least these

the numbers in the specimen 1 investigated more carefully. The pedicels are long, the

'•nts sli<>rt, slightly longer only than broad. Each segment is protuberant at the anterior

a little beneath the articulation with the following segment. < >n this protuberance is planted

a dense brush of bristles; a transverse row of bristles is also inserted on the outer side near

the extremity of each segment. In the upper segments these bristles have the character of thick

and claw-like spines. ( )n the inner side the bristles are less strong and also less numerous.

They form distinct rows only on the upper segments.

The basal segment of each ramus is in most cirri indistinctly divided into two segments.
Thus the o'1, cirrus miglu as well be said to have 13 and [5 as 12 and 14 segments.

The caudal appendages are rather long and delicate. In one of the specimens I
• teil the one consisted of 8, the other of 10 joints. In length they equal the pedicels <>f
the 6,h cirrus. the lO-jointed one being slightly longer. The basal segments are short and broad,
the middle long and narrow, the upper very narrow, but not so long as the middle ones. The
short and thin bristles are planted on the extremity of each segment, the terminal segment
being furnished with a tuft of bristles.

The penis is thick and long, curled together in a curious way, tapering towards the

extremity. where its end is indistinctly bilobed. The articulations are not very plain, yet the

as well as the terminal portion eau be said to be ringed, there being an intermediate

part where the rings can hardly be distinguished. Very long and delicate hairs are scattered

the surface, forming a somewhat irregular tuft at the extremity in the little furrow between

the two points or lobes.

The are small and very numerous. I found a single lamella only. The eggs in

the specimen I have investigated wen- far advanced in development: most of them contained

39

the Nauplii ready for hatching; these larvae showed no tracé of pigment in the eyes. The
greatest diameter of the egg is 0,22 mm.

The specimens taken by the "Siboga" were attached to stones and shells.

This species was collected at :

Stat. 260. December, 16 and 18, 1899. Lat. 50 36'. 5 S., Long. i32°55'.2 E. Depth 90 m. Bottom:
sand, coral and shells. [2,3 miles N. 63' W. from the north point of Nuhu Jaan,
Key Islands],

General Remarks. This is an interesting species, forming a link between the species
with quite normal rami in the 5th and 6th cirri and those in which the inner ramus of these
cirri is quite rudimentary. The "Siboga" took four large and several smaller specimens of this
species. I think it worth while to note, that the orifice of the capitulum, which is a narrow slit
in the full-grown specimens, is broad and nearly circular in the small. In some regards this
species seems to resemble A. xenophorae Annandale — a figure of that species might at once
settle this question \

3. Alepas lithotryac n. sp. PI. IX, fig. 5 — 8'.

Capitulum hardly distinct from peduncle, globular, with low and indistinct carinal crest.
Orifice not protuberant, short and narrow. No scuta; the place these should occupy indicated
as smooth patches of oval shape. The cirri of the 5th and 6th pair shorter than the foregoing
ones. Inner ramus of the cirri of the 5th and 6th pair slightly shorter than the outer rami.

The capitulum of this species in some of the specimens almost insensibly slopes into
the peduncle (PI. IX, fig. 5), in others it is distinctly separated from the peduncle by a contraction.
lts shape is globular, with the carinal margin strongly bowed ; the orifice is narrow and relatively
short, and is straight seen from the side ; the occludent border beneath or behind the orifice is
slightly convex. Along the carinal margin is seen a very low crest which continues along the
peduncle. There is a reticulation of delicate striae all over the surface and deeper wrinkles
occur near the orifice, being placed at right angles to its main axis. Neither striae nor wrinkles
occur at a place of oval shape under or in front of the orifice, on both sides of the capitulum :
these smooth places or patches probably represent the so-called horny scuta of some of the
other species.

The peduncle is very short, its general shape is cylindrical. The surface is indistinctly
ringed; on the one side (in the specimen figured, the left) the base of the peduncle forms a
chitinous expansion with which the little body is attached to the surface of one of the valves
of the Lithotrya.

Size. The length of the capitulum and the peduncle together is, in the largest specimen,
about 4,5 mm., the length of the peduncle being about 1 mm. The other specimens are considerably
smaller; the largest has been used for the description of the shape of the capitulum, as well
as of the structure of the animal's body. It was not furnished with egg-lamellae, but to judge
from the state of development of the ovary, it was full-grown, mature or nearly so.

1 A figure is given in "Illustrations of the Zoology of the R. I. M. S. S. Investigator", Calcutta, 1907. I think Annandale's
A. xenophorae and my A. intermedia are different species. (Xote added during press).

39

I"

\\ ol the structure of the anima] contained within the capitulum has yielded the

followii

Mouth. Labrum distinctly bowed with a mu ol about jo rounded chitinous knobs
at t ie teeth and with a series ol delicate hairs inserted in trom of the knobs

id at the base, conical with several bristles along the outer margin and a
h bristles at the tip.
Mandibles (fig. 6 with three teeth and the inferior angle. The second and third
tooth and the third tooth and the inferior angle at nearly equal distances from another, the
iïrst and second tooth at twice the dist. mee ol the other teeth. The inferior angle is slightly
1 at its extremity and terminates in a nol very pointed tooth, much ressembling the other
eth. Very small, sharp spines occur along the upper edges of tooth 2 and 3, as also
along the upper edge and along the under edge near th< extremity of the inferior angle. Near
the dge the surface of the mandible is furnished with numerous hairs which are placed

in groups of two <>r three; some hairs reach over the free edge, numerous others are planted
along the inferior margin.

Maxillae (fig. 7) with three strong spines above a rather broad notch and the
part beneath the notch slightly produced. Between the three nj >] x • r sj)ines, of which the first
is 1>\- far the strongest, a few delicate hairs are planted, one of which is distinctly serrated.
In the notch are a few short hairs and about 10 rather strong spines, arranged in a doublé
row along the lower part. Hairs in groups ol two or three on the surface near the free edge;
a n>w of stronger hairs along the inferior margin and a few hairs forming a group at the upper
margin near the insertion of the upper spine. Apodeme rather long.

(•titer maxillae short, rounded at the extremity with a dense tuft of spines near
that extremity and along the inner side. Between the longer spines are inserted numerous very
delicate hairs.

Cirri short and nearly straight, hardly curved. First pair very short, 2nd — 4* pair
longer than the others, s'h and 6th pair considerably shorter than the foregoing ones.

First pair placed close to the mouth, at a little distance trom the second. with
short and rather unequal rami of 5 and 6 segments. The shorter ramus has the first segment
indistinctly divided into two segments and the four following ones decreasing in dimension. Hairs
on the segments numerous, increasing in strength from the first to the fifth segment; about
the middle of its length each segment has a distinct transverse row of longer hairs. The last
lent bears two claw-like spines at the tip. The longer ramus is considerably broader; it has
six distinctly separated segments, decreasing in dimension from the 1 ': to the o!h. The lower
densely covered with hairs, the distal in a less degree. The last segment has four strong
spines at the tip: these are not (piite so strong and a little less curved than those al the tip
of the shorter ramus.

The 2"'1 to 4,h cirrus has nearlj equal rami of 9 to 10 segments. The shape of the

3 almost quadrangular, with the exception of the first segment of each ramus, which

trom 2 to 3 times as long as broad and of the last si m.nt. which is small and rounded

tip. I he bristles form transverse rows near the extremity of each segment and a tuit

40

4i

of more delicate bristles are placed about the middle of the slightly swollen, anterior margin
of each segment. Of those arranged in a transverse row, to begin with the 4* or 5th segment,
two or three are much thicker and stronger and have the shape of claw-like spines.

The 5"1 and 6th cirri are shorter than the foregoing ones, the ólh being not inconsiderably
shorter than the 5111, the latter equalling about 3//ds the length of the cirrus of the 4th pair. The
rami of the 6th pair (fig. 8) are slightly unequal and have respectively 7 and 9 segments.
On the posterior margin of each segment, near the extremity, a group of spines are planted
which correspond with the stronger ones of the transverse rows of spines of the segments of
the 2nd — 4th cirrus. From the 4111 to the 8th segment two of these spines are claw-like and strong,
the one, however, more so than the other. The last segment bears two claw-like spines at the tip.

Ca u dal appendages (fig. 8) thin, having five tapering segments, and being a little
longer than the pedicels of the sixth cirrus. Delicate hairs are planted on the extremity of each
segment, the last segment bearing on its summit a tuft of slightly longer hairs, the longest of
which is nearly equal to the length of the segment itself.

Penis (fig. 8) rather thick, with the terminal part narrow and conical towards the
extremity. The middle part is distinctly ringed. A few delicate hairs are scattered over its
surface, a tuft of such hairs being planted close by the tip. On each ring of the annulated
middle part a transverse row (fig. 8') of short, broad spines of very peculiar shape is planted.
They look like little hands with extremely short and pointed fingers. The number of these
peculiar appendages is largest on the broadest segments, their maximum number upon one
segment being 15.

The specimens of this species were found attached to the valves, partly to the outer,
partly to the inner side of Lithotrya nicobarica. I observed from 2 to 7 specimens — most of
them very small ones — attached to one Lithotrya. They must be a nuisance to the animal,
especially when they are attached to the inner side of the valves ; they feed, in all probability,
on the same planktonic matter which the Lithotrya is trying to get hold of.

The Lithotrya nicobarica was collected at :

Stat. 225'. November S, 1S99. 2700 m. N. i85°E. from Southpoint of South Lucipara Island.
Reef-exploration. Bottom: stone.

A small specimen of the same species was found attached to a specimen of Lithotrya
conica n. sp. collected during the "Siboga" expedition at Txur-Reef', a very small one to
one of the specimens of L. tnmcata, collected at Haingsisi, Samau Island, Timor.

Observation. I think that this species comes close to Alepas quadrata Aurivillius.
I consider and describe it as different, partly because the general shape is quite different, partly
because it seems to live under quite different conditions, partly because the structure of the
appendages of the animal's body does not agree with that of the species of Aurivillius. The
short and straight cirri composed of 8 — 10 segments only are peculiar to the present species.
The interesting small spines which cover the surface of the penis occur most probably also in
A. quadrata. Aurivillius says (1. c. p. 32) that this organ is "hie und da mit rückwarts
gerichteten Borstenen versehen". Perhaps there exists a certain relation between the one or
both species and Alepas malaysiana described of late by Annandale.

41

SIBOGA- EXPEDITIE XXXI a. 6

4»

n sp. PI. IV, fig, 1 7 and 1 8.

\ sin cimen of a species of the genus Alepas differenl from the known

taken bj H.M.S. "Siboga" at Station -"'7. Vccording to th<- label the specimen was found

hed te the spines of / ijk, on which the specimens <>l" ./. morula were

nd. lt differs trom tli.it species at first sighl 1 " by its form which is more regularly

ded oval; 2' by the absence of the tubercles on the surface; ;' by the somewhal larger

orifice of the capitulum; and ( by the shorter and more cylindrical peduncle. When 1 received

it. th<- specimen was ii" longer attached to th<- Echinid-spine as was the case with the specimens

• that the peduncle may have been longer in reality

The shape of the capitulum, the not very distinct crest at its carinal edge, the way in

which the capitulum is separated from the peduncle can be best judged, 1 think, from th<-

figures 17 and 18 "f' PI. IV. lh<- length of the capitulum and the peduncle together is nearly

1 1 mm., the capitulum alone measuring about 8 mm. Scuta absent or entirely hidden under

chidnous membrane.

TIn- species to which this specimen belongs has no doubt a certain resemblance to
'aponica Auriv., but I do not believe it can be identical with it. Only dissection and full
investigation of the parts of the mouth, the legs etc. might settle this — but I feel unable to
so without destroying the specimen.
The specimen was taken at:

Stat. 207. December 20, [899. Lat. 5 54 S., Long. 13256.7 IC. Depth 984 m. Hottom: grey
mud with a brown upper layer.

As 1 have pointed out already in the introduction to the genus Alepas, of all the known
species this form, next to A. Lankesteri, inhabits the greatest depth. This is also wie reason
why 1 think identity with ./. j aponica highly improbable.

4. Alepas tennis n. sp. PI. IV, fig. 19.

Still another species of the genus Alepas is represented in the collection of H. M. S.
"Siboga". There is again only <>ne specimen and it is very small — whether full-grown or not
1 am unal.le to decide. It resembles Alepas Lankesteri (ïruvel to a certain extent yet it is
much smaller and the resemblance might on closer examination turn out to be superficial only.

Like Alepas Lankesteri the capitulum is devoid of scuta and furnished with a continuous
ridge extending from the orifice to the peduncle. I have figured the little animal (PI. IV. fig. 19),
the total length of which is 6.4 mm.-, the figtire will. I hope, enable this form to be recognised,
should it again \><- found.

It was taken at

Stat. 251. December 8, [899. Lat. 5 js .4 S.. Long. 13J o.jIC. Depth 204 m. Bot torn: hard
coral sand.

Gi neral Remark. 1 do not think it a good custom in genera! to describe such forms
5, of which it is impossible to give a full description for want of material. When
eographical distribution and the bathymetric range of the known species of the

4-

43

genus, for the sake of convenience names were also given to the two last mentioned forms. The
number of known species of the genus Alepas not being very large and the species more or
less recoo-nisable from their outward shape, no confusion will arise I hope from my naming these
two forms, deviating in so doing from what I consider a very good rule in general.

Genus Microlepas n. gen.

Capitulum without valves, with rather large and prominent aperture. Mandibles and
maxillae foliaceous without teeth or stronger spines. Cirri of the first pair one-jointed without
rami, those of the 2nd — 6th pair with uniarticulate rami of very unequal size.

This cirripede resembles at first sight a species of Alepas; it cannot be considered as
belonging to that genus, however, owing to the structure of its mouth-parts and cirri. Only one
species of the genus is known ; to give a more detailed description of the genus is useless and
even dangerous, as it is quite impossible to decide what characters have generic and what
specific value only. The only specimen of the species of this genus which is at my clisposal
was found by Prof. Max Weber attached to one of the spines of Diadcma saxatilc (Linn.) at
Station 53. I propose to call the species:

1. Microlepas diadcmac n. gen., n. spec. PI. X, Fig. 8 — 16.

Capitulum blending insensibly into the short peduncle, aperture oval, large, situated at
some distance from the slightly produced summit. Peduncle indistinctly wrinkled.

Capitulum elongate-oval, moderately flattened (PI. X, fig. 8); its summit bluntly pointed,
forming a small conical excrescence in front of the orifice. The membrane composing the
capitulum is thin, flexible, smooth on the left, longitudinally wrinkled on the right side. Orifice
laro-e, broadly oval with darker, brownish coloured margin. Peduncle short, blending insensibly
into, but a little narrower than the capitulum ; surface with an indication of transverse wrinkles.

The colour of the capitulum is light greyish-brown, but it has been in spirit for several
years. The size is, including the peduncle, 5,6 mm.

The little animal's body was hanging out of the orifice of the capitulum, it was distorted
and in a somewhat deteriorated condition. A piece of the sack or mantle was loosened from
the inner side of the capitulum and also forced out of the orifice and a cluster of eggs was
attached to this piece of mantle. The body was to some extent covered by these parts, so
that I only succeeded in making out its structure by loosening it from the capitulum.

I found the mouth not very prominent and placed at a little distance from the first
pair of cirri. The prosoma was well-developed, its muscles rather strong, the part of the body
representing the thorax small, rather rudimentary.

Of the parts of the mouth, I found the 1 a b r u m not distinctly bullate or swollen with
a straight crest without distinct teeth and with small triangular pal pi. The mandibles and the
maxillae were relatively large, and extended beyond the labrum and the outer maxillae; they
were of a very peculiar shape.

43

■1 1

The mandibl have no teeth bul .1 smooth and rounded edge, along which

te hairs in several rows lts inferior angle is acuminated and ends in
bristle, which howevei can hardly be cal led .1 spine.
m a \ i 1 1 a • io) have the edge also rounded, without steps separate from one

anotl notches and without stronger spines at the upper corner. Along the rounded i

numerous delicate hairs are inserted in several i"\\s; the lowesl corner lias two slightly stronger
and another is seen at a little distance from it. A rather stout and not very long
ittached to the maxilla. Both maxilla and mandible are thin and delicate, their
reaching beyond the tip of the mouth on the whole.
Outer maxillae fig. n represented by very small rounded structures with delicate
their inner surface and at the tip. A group of apparentlj stronger hairs on a little
nded e> tr the summit these hairs, however, were all broken "ti

I irst pair <>f cirri (fig. i:i quite rudimentary, represented bj a one-jointed conical limb
with a few short liairs at tin- tip.

nd-sixth cirrus (fig. 13—15) of about the same structure: each consisting of a
two-jointed pedicel and two rami, each oi which is represented by a single segment only,
however about twice as Ion- and more than twice as broad as the other. The 1 irrus
of th'- second pair has the lower segment of the pedicel shorter and the upper longer, the
thinl cirrus lias about the same structure: in the 4"' — 6th cirrus. however, the two segments
of the pedicel are of about the same length. In all the cirri a number (4 — 6; of stronger hairs
are planted on the pedicel at the base of the segment which represents the stronger ramus,
and another group of even longer and stouter hairs at the base of the more rudimentary ramus.
Both rami bear at their rather broad, truncated extremity a dense tuft of very thin and delicate
hairs which are irregularly curled, of very unequal length but altogether rather long. As a rule
parate group of hairs is inserted at or near the extremity of the stronger ramus, near its
extremity. Such a separate tuft of slender hairs is also observed <>n the inner side near the
extremity of the segment representing the smaller ramus.

The cellular (plasmatic) contents with muscles and nerves have shrunk from the chitinous

surface of the legs of the animal, due probably to the alcohol in which it was kept. The hairs

through the chitinous covering standing with their plasmatic contents in communication

with the contents of the leg itself. The contents are distinctly denser and darker coloured near

the extremity where the hairs seem to take their origin.

Caudal appendages not observed, most probably wanting.

Penis fig. 1; rather broad, short, not extending beyond the extremity of the cirri ol
pair, truncated at the extremity where it bears a tuft of short hairs. Numerous very
short hairs scattered over its surface.

The little animal wa ually well-developed and provided with ovigerous lamellae,

:. however, had not the shape of leaves hut rather of clusters of irregular shape in

formed several layers. As 1 described above, one of these clusters had been

1 of tli- sack of the animal, the other being still seen in the cavity. The eersrs

and small. They have an elongated form, at h-ast in the highly developed

tt

45

condition I observed them in (fig. 16). Their size was: long 0,26 — o,2S mm., shortest diameter
about 0,1 mm.

This species is represented by one specimen only. It was found attached to the extremity
of spine of Diadema saxatile (Linn.) collected by H. M. S. "Siboga" at:

Stat. 53. April 21 — 22. Depth up to 36 m. Bay of Nangamessi, Sumba.

I was at the end of the description of the pedunculate Cirripedia collected by H.M.S.
"Siboga" when I received this small and very curious form. I consider it so very interesting,
that, though it is represented by one specimen only, I describe it as a new species. This compels
me, however, to create for it a new genus also, as it is perfectly impossible to range the
species under one of the existing genera. I am sorry to say that in consequence of its being
represented by only one specimen, which is moreover slightly deteriorated, it has not been
possible to study this new form in such detail as could have been desirable. Having dissected
numerous and very small forms of Crrripedia, I think it hardly possible that I should mistake
another part for a mandible or should overlook a pair of cirri, but the very peculiar shape of
these parts in the present animal have, I must confess, given me great trouble. I should have
prefered, before publishing a description, to control the details of its structure with the aid of
a richer material — I have tried in vain, however, to procure such.

The outer shape of the capitulum of this new form is much like that of Alcpas. I could
not study the muscles of the peduncle in order to see whether they run up from the peduncle
and surround the capitulum — ■ as is the case in Alcpas — without quite destroying the type.
But I think it probable that there is correspondence in this regard also between the two genera.
In Alcpas cornuta the inner rami of the 5th and 6lh cirri are rudimentary, as was discovered by
Darwin, and in some other species of the same genus a similar inequality has been observed.
Gruvel calls this the atrophy of one of the rami : the cirri of Microlcpas diademae show this
atrophy in both rami and to a much greater extent ! The cirri of Auclasma have, according
to Darwin, a shapeless and rudimentary appearance, being quite spineless, and not articulated.
Yet their anterior faces are more or less distinctly lobed, so that prominent steps can "be
counted, manifestly representing so many segments", as Darwin says. Though the cirri of
Microlepas diadema are furnished with long hairy bristles, they are in a much more rudimentary
condition than those of Anelasma. In the genus Gymuolcpas, as described by Aurivillius, all
the cirri have the rami of the same length, composed of 7 segments only; these rami in all
the cirri are almost of the same length as their pedicels — whereas those of the 2ncI — 6th pair
in all other Lepadids are longer than those of the first pair and as a rule twice as long as
their pedicels or even longer. Aurivillius compares nis new genus with Aiielasma and says
that a reduction of all the cirri has occurred in these two genera. There can be 110 doubt,
I think, that a much more considerable reduction has occurred in Microlcpas diadcmacl

The parts of the mouth show an analogous reduction. So far as I know, all pedunculate
Cirripedia have mandibles with at least two, as a rule three or four, in some genera more

45

:h in a single r<>\\ ; they are always by far the strongesi pair of parts in the

about doublé the size of the maxillae. Now the mandibles of MicroUpas

ili whatever, the inferior angle only hein- furnished with a somewhat

spine than those which are planted along the free edge; further, the mandible <>f tliis

c'irr; i hardly be said to be larger than the maxilla. The latter in all other Cirripedia

al the upper corner and numerous more or less strong spines along the edge:

in .1. diademae it has the edge regularly curved and furnished with several rows of

delicate hairs its inferior angle showing a slightly stronger spine-like hair, an other

being inserted at a little distance from that angle.

I'hc extremely rudimentary condition of the lïrst pair <>f cirri and the fact that caudal
appendaj wanting complete the description of a pedunculate Cirriped, which so far ;is

structure of the body with its articulate limbs is concerned, must be considered as one of
the most reduced at present known. This reduction concerns the body of the little anima! only —
capitulum gives at least the impression of being that of an ordinary Alepas. It is of course
very difficult to understand how such an exceptional reduction has taken place and the circum-
stance that I am quite ignorant of the mode of life of Diadema saxatile makes it perfectly
hopeless to seek for an explanation. I do not know, for instance, what position the club-shaped
spine, at the tip of which our Microlepas was placed, occupies on the body of the Echinid,
whether this spine is highly moveable etc. There is every reason to think, that the reduction
of the limbs, parts of the mouth and cirri, is in accordance with the nature of the food and the
way in which this is grasped by the little animal — I do not know, however, what ditïerence
there is between its prey and that of other Cirripedia. We are therefore unable to explain the
physiological side of the phenomenon; its morphological importance lies in the high degree of
reduction and in the fact. that — so far at least as our present knowledge goes — no real
intermediate forms can be said to occur which could bridge over the gap between an ordinary
Alepas and this cripple-like form.

Genus Ibla Leach

The Cirripeds of the genus Ibla are characterized by the absence of calcareous matter

in the valves and spines of the peduncle, by the presence of four valves (two scuta and two

also by the fact that (in the one of the known species) the sexes are separated, or

that (in the other species) the "masculine efficiency is aided by one <>r two complemental

male. 1 >\k\\i\ .

Of this genus two species were known to Darwin in 1851. Since that year no new
species have been described, nor have the original s|)ecies of Darwin been often met with. In
his list of 1897 Wei 1 nf.r ' mentions the occurrence of Ibla Cumingi Darwin in the Red Sea,
in the neighbourhood of the Philippines and al Zamboanga (also Philippines), and of Ibla quadri-
valvis (Cuvier) at Van Diemensland. Of the latter species Grüvel9 found numerous specimens

1 Um . u .. Verzeichois u. s. w. Archiv f. Natu: 1897 Bd I.

Cirripides appartcnant a la collection du Muséum d'histoire naturelle. Nouv. archiv. du Mn

,03.

46

47

(full-grown and young) in the collection of the Paris Natural History Museum : they were from
"Port du Roi Georges" (King George Sound, West-Australia?), from Djibouti, from the east-
coast of Madagascar and from Mascatte. In both papers published by Gruvel j he treats the
o-enus Ibla rather extensively, but any newer literature on this genus seems not to be known
to him either.

During the cruise of H. M. S. "Siboga" specimens of /^/«-species were collected at
different places in the Malay Archipelago. They belong to two different species : I. Cumingi
and another which is different from the two known from Darwin's Monograph. It comes near
to I Cumingi and is unisexual like that species; like both hitherto known species it is a
true littoral form. All the specimens collected by the "Siboga" were met with during reef- or
shore-exploration.

To distinguish the species I give the following table :

Ibla

i. Hermaphrodite with complemental male (or males) /. quadrivalvis (Cuvier).

2. Unisexual with dwarfed males.

a. Yalves of the female coloured blue along the lateral margins

and on the upper interior surface I. Cumingi Darwin.

b. Valves without blue margins /. sibogae n. sp.

i. Ibla Cumingi Darwin.

Darwin found the specimens of this species "invariably attached to the peduncle of Polli-
cipes mitella, in groups of two or three together". The "Siboga" collected Pollicipes mitella
on two different occasions : at Labuan Badjo (Flores) and in the southern part of Molo Strait.
Ibla Cumingi was found attached to two of the specimens from the latter place.

The specimens are not very numerous, nor are they very large. They not only show
the blue margins of the valves, but the structure of the body, of the parts of the mouth, the
cirri and the caudal appendages corresponds with Darwin's description.

In the collections made during the "Siboga's" cruise there is another group of specimens
which I consider belong also to this species. They were taken however from the reef in Palos-
Bay, Celebes, and were not found attached to the peduncle of Pollicipes mitella. Their valves
have blue margins and the structure of the parts of the mouth and of the limbs is much the
same as in the specimens found at Labuan Badjo.

( Weltner (1. c.) mentions the occurrence of this species in the Red Sea ; as Pollicipes
mitella is not known to occur there, this seems to be another instance of this species not living
"invariably" attached to the other Cirriped.)

In all the specimens I dissected I found, at the place indicated by Darwin, a little male.
Darwin's description of these males is detailed and on the whole correct so I need not repeat
it here. A full description of the (complemental) males of Ibla quadrivalvis is given moreover

Gruvei., A., Civnpèdes des expéditions scientifiques du "Travailleur" et du "Talisman". Paris, 1902.

47

id in m<>M regards this holds g 1 also for the male "I Ibla Cumingi, There

is howe> tail which 1 found different from Darwin's description. Darwin speaks of an

>n of the peduncle of the little male passing obliquely through the chitine

ium lining the sack of the female, and running along amidst the underlying

I inosculating fibrous tissue, attached to them by cement al the extremity. I have

iys found the little male attached to the wall ol the sack b) means ol .1 di 1 ol cement,

but 1 could n«u observe that it passed through thal wall. 1 think that the description given by

Grüvel, where he ^.i\^ for ll>la quadrivalvis) thal the mantle Darwin's "sack") sometimes

forms a proliferation, through the centre "I which passes the extremity "l the peduncle of the

. explains what h.is been observed bj Darwin. According to Grüvei the tubular pan of

the male "s'enfonce dans Ie manteau >1<: 1'hóte". This means, I think, that the mantle forms

an invagination to receive the extremity of the tubular part, not that this passes through it to

l with the muscles of the female's or hermaphrodite's pedun< [1

This species w.is collected at the folio wing places:

St.it. 51. April 19, [899. Shore-exploration in Madura Bay and other localities in thesouthern
part of Mi >lc > Strait. A few smal! specimens attached to Pollicipes mitella.

St.it. 86. June 18—19, [899. Reef-exploration Dongala, Palos Bay, Celebes. Specimens loose,
i. e. not attached to Pollicipes mitella. (N.B. No specimens of Pollicipes were
collected at Station

2. //'Ai sibogae n. sp. PI. IV. fig. 20—22. PI. V, fig. 1 — S.

I emale. Valves of a uniform dirty brown or red brown colour — no blue, neither
along the lateral margins nor on the upper interior surface. Spines on the peduncle without
blueish brown rings. Caudal appendages only slightly longer than the pedicels of the sixth
cirrus; rami of the first cirrus unequal by 2 — 5 (as a rule 4) segments.

Male. Closelv resemblingf that of /. Cumingi Darwin.

This species is unisexual like /. Cumingi Darwin, which it also resembles in many other
Is. The absence of the blue colour, together with a few slight differences I perceived in
the structure of the parts <d the mouth, the cirri and caudal appendages, as also the circumstance
that /. Cumingi lives attached to Pollicipes mitella as a rule, made it necessarv to consider
the present form as a different species. Later investigation of a richer and il" possible quite fresh
or living material of both forms may show however that they are not specifically different but
only represent two varieties of one species.

1 e m a 1 e

The animals are somewhat variable in shape, that pari of the peduncle to which the

capitulum is attached and which as a rule is considerably broader than the inferior part, sometimes

forming an abrupt swelling and sometimes quite insensibly sloping into the inferior part. In other

mens there is a distinct constriction beneath the broader part, almost in the middle of the

- '. du "Talisman". Paris, 1902.

49

peduncle. In a few probably younger — specimens the peduncle is nearly cylindrical or

c< >mj iressed cylindrical.

The colonr of the animals is sometimes red-brown (e. g. in specimens from the Bay of
Bima) sometimes dirty brown (specimens from Kwadang Bay, Pajunga Island, for example).
The svvollen part of the peduncle is as a rule darker coloured than the inferior part, and darker
also than the valves. In some of the specimens the valves have slightly darker maro-ins, the
clark colour havingf however a blackish-brown, not a blueish tino-e.

The spines or horns of chitin which thickly clothe the superior part of the peduncle are
"nearly cylindrical, irregularly curled, and nodose or slightly enlarged at intervals: the apex
smooth and pointed; the exterior surface longitudinally and finely ribbed" — exactly as Darwin
says they are in I. Cumingi. But whereas he says, that those of the latter species are "ringecl
with pale and dark blueish brown, which on pressure becomes slightly opalescent with pale
blue and hery red", those of /. sibogae never show a tracé of blue and are always yellow- or
brownish-yellow coloured.

The shape of the valves corresponds in general with the description given by Darwin
of the valves of /. Cumingi. The tips of the valves, of the terga especially, are often broken
off and their exact shape is difficult to make out in consequence. The scuta have the outer surface
much more plainly marked by zones of growth than the terga. The valves are longitudinally
ribbed, the delicate ribs seem to correspond to those of the horns on the surface of the peduncle
in clistance from one another as well as in delicacy.

Fig. 21, A and B of PI. IV show the internal surfaces of the valves after being cleaned
with caustic potash. When not separated the scutum (A) at the outer side overlaps a portion
of the tergum B, so that the scutal margin of the tergum (from c to d in the figure) reaches
as far as the pointed line to the left side of A. What Darwin calls the growing or corium-
covered surfaces of the valves, the parts covered with epithelium, are easily to be clistinguished
from the free horn-like portions. In the scutum this part is triangular but it is not of the same
length as the horn-like portion, as Darwin says it is in the scutum of I. Cumingi, but considerably
shorter. In the tergum the growing part is of an irregular diamond shape. The chitinous structure
of both valves is very characteristic : the figures 21 A and B try to give an idea of it. The crest
running from the summit of the triangular portion to the tip of the scutum, with the short lateral
branches directed towards the occludent margin of the valve, seems slightly more developed in
I. sibogae than in I. Cumingi.

The shape of the body and the structure of the limbs in general is the same as with
I. Cumingi. As in that species the chitinous covering of the prosoma bears very delicate,
pointed hairs. I wish to point out the following, perhaps not very important differences for the
parts of the mouth and the other limbs.

Mouth. The lab rum has from 3 — 7 small nob-like teeth: in younger specimens 3 or
4 onlv, in one of the older ones 6, in another 7. Between these nobs short and extremely
delicate hairs are planted. Darwin says that there are 110 teeth on the crest of the labrum in
I. Cumingi and that the same part in I. quadrivalvis is "a little roughened with minute points".
Now the teeth of the labrum of /. sibogae are hardly more than minute points ; I may add

49

SIKOGA-EXPEDITIE XXXI tl. 7

that I • "ii tlf cresl of the labrum in the specimens "i /. Cumingi

PI l\
il pi of tli«- labrum are small, rounded al their ends; the hairs on the palpi
e tuit .n the extremity, those on the palpi of both sides hardly touching
when in the natural position. The outer margin bears .1 row ol extremely
minute haii

Mandibles. In one of the specimens from Station 17 the upper edge of the second
not pectinated. The inferior angle is onlj slightly produced in all the mandibli I
I; it is pectinated as figured (fig. 22
Maxillae PI. V. fig. 1 . I dge ver) indistinctly indentcd; it supports, be ides the thi

.1 number ol moderately strong spines, which can hardly be divided into
stronger m\A more d< mes. Maxillae small, apodeme short.

The shape of the outer maxillae (fig. 2), of the conical prominence clothed with

bristles and coloured purple lying over the ir.fra-oesophageal ganglion between the bases of the

tlrst pair of cirri, corresponds exactly with Darwin's description of the same parts in /. Cumingi.

Cirri. rhe tirst cirrus has the rami unequal in length by from 2 to 5 segments, by

about two segments in /. Cumingi, according to Darwin. I dissected in all six specimens of

•■ and I found the following numbers of segments for the first cirrus: 21 — 17, 2c — 16,

14. 17 13, 17-12 and 14 12. These- numbers show greater variety than is the case

in most other Lepadids.

(In a specimen of /. Cumingi I found a difference of 5 segments in the first pair of
cirri, in another of 3 segments).

The other cirri conform in general to Darwin's description of/. Cumingi. Investigating
carefully the arrangement of the bristles on the segments of the sixth cirrus, I found very often
on the anterior surface not three pairs of spines, the lowest pair being minute, but tour pairs,
three of which were stronger, the fourth very delicate. A number of segments showed this
arrangement, others on the same cirrus the three pairs as described by Darwin for /. Cumingi.
(On the 6lh cirrus of a specimen of /. Cumingi collected at Station 86 I also found tour pairs of
bristles on some of the segments - however, the number of segments showing this arrangement
was very small .

The caudal appendages have from \- to [3 segments. The upper segments which

in /. Cumingi "are slightly constricted round the middle, so that they resemble in a small

degre< an hour-glass" (Darwin), in /. sibogae do not show the hour-glass shape as a rule. In

some specimens the two last joints show a tracé of that peculiar shape. which I found distinctly

1 in the last si\ segments of the caüdal appendages of specimens of /. Cumingi. As

in this species the caudal append of /. sibogae are as long as or slightly longer than the

Is of the sixth cirrus.

li -lamellae are not very large, nor is the number of eggs in each lamella: a

lamella contains one layer of eggs only, in that of a medium-sized specimen trom Station 61

Il 2 |' In each lamella the eggs are kept together by an extremely delicate

ear membrane, which surrounds each egg as a capsule. At one place the margin of

5°

the membrane forms an irregularly folded thickening by means of which the lamella is attached
to the wall of the sack and which therefore represents Darwin's "ovigerous frenum".

The eggs are not spherical (as those of I. quadrivalvis, according to Darwin) but
oval, the proportion of the longest to the shortest diameter being in one case as 40 to 34, in
another as 40 to 30. The size of the eggs was found to be different in different specimens :
the larger females probably producing larger eggs. The eggs of a small female from Labuan
Badjo (West coast of Flores) measured 0,14X0,1 mm.; development was only beginning. A
larger female taken from the corals of the island of Billiton contained eggs of 0,21 X o, 16 mm.;
these eggs showed the larva nearly quite developed, with the black Nauplius-eye, the three
pairs of legs etc.

(Darwin does not give the size of the eggs for /. Cumingi\ one of the specimens of
that species collected in Molo Strait was furnished with egg-lamellae. The eggs had the same
shape as those of /. sibogae. Their greatest and shortest diameters measured 0,18 and 0,13 mm.)

The size of the specimens is as variable as their shape. The larger specimens from
the different Stations have a length from 17,5 — 10 mm. The longest specimens are rather
narrow : thus the specimen of 17,5 mm. in length is nowhere broader than 4 mm. and its breadth
measures 2,3 mm. where narrowest. The stoutest specimen of all had a length of about 14 mm.,
its breadth being 6,5 to 7 mm. in the upper part and in the inferior part of the peduncle it
was nowhere narrower than 5 mm.

A few of the specimens are attached to little pieces of stone, in one case two, in another
four being situated on different sides of one stone. A few were found attached to a piece of
broken shell of a Balanid. Most of them, however, are quite loose. The inferior extremity of
the peduncle forms a flat disc in numerous specimens, and it is with this disc that the animal
is cemented to the stones or other objects on the bottom of the sea.

Males

I opened a dozen specimens of the females of I. sibogae and found with a few exceptions
only one or two males attached to the wall of the sack. They were of very different size and
development: as a rule they were small and immature, in two cases I found them relatively
laro-e and undoubtedly full-grown. But even in the latter cases I found a considerable difference
in size between the two males attached to the same female. The figure 20 of PI. IV shows two
laro-er males as they were found in situ~\ whereas the larger has a length of about 3,5 mm.,
the other measures only 2,5 mm. The other full-grown couple of specimens showed about the
same proportions and dimensions.

The immature or not quite mature specimens varied in size from 1,1 to 1,4 mm., one of
them measuring only 1,8 mm. The latter showed the testes in nearly quite developed condition.
Males of 1,4 mm. were in several cases found attached to the sack of a female which was
provicled with ovigerous lamellae.

The number of males attached to a female is as a rule two ; they are found attached
to different parts of the interior wall of the sack, but seldom at the place where Darwin found
the little male of /. Cumingi, viz. "in a nearly central line, at the rostral end". I found them

51

to the left and at th< bottom of tl When two were preseni PI IV,

I th.it the anterior portion of the one touched the posterior end
. » li.it .1 mucli constricted part of the males through the skin

the female; thei rule a thickening ent round about the ba

.i\ of the peduncle with its cement-ducts passes through this cushion
üt. I»ui I : that it also went through the wall of the or mantle).

PI. V are drawn from a male o im. 1>\ part in

:it of tli*- oblique fold tin • thorax, the rest the peduncle of the animal. The thorax supports
tw rudimentary cirri and, more t<> the so-called ventral side, the part ol the mouth.

I labrum i i «roa.l with a nearly straight all palpi. The latter have a i

at their j •* >i i it< -. 1 extremity. 1 In- mandibles have three teeth, more diverging
in in the fem te inferi e is quite undeveloped: .i mere nob with ;i rudimentary

point it spine at the extremity. The maxillae show the three upper spim . and two more spines
the in: nd of the edge separated by a notch from the upper spines. The two stand

at a little distance from one another and are considerably shorter than the upper spinis, two of
which are again stronger than the third which is planted between the two. TIn- outer maxillae
are relatively large; they show a row of smal! bristles along the curved outer side, they have
the so-called olfactory oi il the end of flat tubular proo exactly as in the f< and

jnst as already described by Darwin.

The two pairs of limbs which represent the cirri have one ramus only. Darwin concluded
from the position of the excretory orifio nital porus and anus) that these cirri answer to the

hTth and sixth pair in other Cirripedes — but this view is not supported by the circumstance,
that I da rudimentary capsule in the basal segment of the first pair (in a small specimen

of t,4 mm.), inuch resembling the so-called auditory sack. Hence 1 would conclude that the
first leg represented the first cirrus of an ordinary Cirriped.

These legs vary much in size and are often represented by one- or two-jointed rudiments
only, either on one or on both sides of the same individual. I found them relatively large,
the first pair composed of 5, the second of 6 segments, in the 2,5 mm. long specimen which
accompanii 3,5 mm. male of figure 5. In the largest of the two (the front par) of which

is figured PI. V, fig. 4) the basal segment which according to Darwin represents the pedicel
of the cirrus. and which is beautifully pigmented with brownish purple, was very large in the
one cirrus as well as in the other. The anterior cirrus which was smaller than the posterior
and planted a little lower down on the thorax had four segments besides the basal one; the
posterior cirrus or leg had the same number, the terminal segment being moreover indistinctly
divided into two segments. Little brushes of spines are planted on the the segments,

htly more prominent towards the dors. il side.

In the fig. .( of PI. V I have indicated the free edge of the thorax as seen through the

nent of the last .cirrus. Following that edge behind the last pair of cirri we see that

it forms a round e a rather stout papillus, which projects freely at the so-called

body. This papillus mo 1 probably represents the penis I would say so

with . .. if I had heen successful in d ing the genital porus at its surface

53

or free extremity - - but this is not the case. In the other larger (nearly full-grown) specimen
I have investigatecl, I did not observe this papilla or, better perhaps, excrescence. In two of
them I observed the two closely approximate, flattened points mentioned by Darwin as being
present between the bases of the last cirrus. These are considered by Darwin as the caudal
appendages in an extremely rudimentary condition ; close outside these rudimentary points on a
slight swelling is the anus, according to Darwin. I need hardly point out that the excrescence
as figured by me would not be called a slight swelling by Darwin. I may add that I could
distinguish a small porus behind this excrescence, between it and the free projecting part of the
oblique fold - - whether this porus really represents the anus I have not been able to make out.

It is not the place here to enter into more details with regard to the anatomy of this little
male. With the material at my disposal it would hardly have been possible to penetrate much
farther into the mysteries of its structure than Darwin did by dissection and Grcvel (1. c.) by
applying the more modern method of cutting sections. There are several points of great interest
connected with these males — I think they will offer a very fruitful subject of research to the
zoologist who studies their anatomy as well as their biology at the place where he finds them
on the coral reefs.

An important point yet to be made out is their metamorphosis. They pass no doubt
through a Cypris-stage ; but the youngest stage observed by Gruvel in all essential points —
but for its immatureness — resembles the grown-up male. Darwin observed the larvae of
I. quadrivalvis in this stage and distinctly saw "all the essential points of structure in the
larvae of other Cirripedes at this stage" but he did not observe the metamorphosis itself.

Another essential point would be to determine whether or not these little males feed
independently. Darwin supposes that the male Ibla seizes its prey with its mouth through the
movement of its long flexible body and I cannot understand how it would do otherwise ! But
Gruvel seems to admit that the male lives parasitically on the female : derives its nutriment
from the much bigger female. He came to that conclusion from the fact that the wall of the
stomach is not furnished with calyciform cells, that he could not tïnd a tracé of digestive glands
and that the stomach of the specimens he investigatecl did not contain food. But taking into
consideration the perfectly well-developed mouth parts, the long oesophagus, the rather large
stomach I think it difficult to share Gruvel's opinion in this regard. How could they take
nutriment, if not with their mouth or digest it if not with their alimentary canal? The body and
all its appendages are coverecl with chitin ; the only direct attachment to the wall of the female
is originally by means of the prehensile antennae, the cement glands situated in the undermost
part of the peduncle afterwards secreting quite a cushion or ball of cement which imbeds these
antennae. I need hardly say that from that side no food can enter the body of the male.

I found the structure of the cement-glands, -ducts etc, as also that of the male genital
organs, the more or less compact globular balls composing the testicles and the doublé pear-
shaped vesiculae seminales in accordance with Darwin's and Gruvel's descriptions - these
parts may be considered as well known. Perhaps the nervous system is not so well known as
yet. Gruvel describes two ganglionic masses, the one lying dorsally from the alimentary canal
and representing the cerebral (supra-oesophageal) ganglion ; the other lying ventrally from the

53

5 1

m between the two ductus cjaculatorii. I Ie could not make ou1 the chords "connectifs")

unitii lion uiili the other, but he admits that such nervous chords <\i^t. I did

them either, but 1 found that .1 rather lai tuated between the eye

and the wall ol itomach, v tli.n the eye nearlj rests on or against this ganglion. From

this the optie ganglii en laterally as in fig. 3 of PI. V is oval, but which is

heart-shaped when seen from above, two very distinct nerves run, as may 1"- supp

ld not be made out, t<> the I ganglion.

Th( "S this species al the following places and station

March 19 21, 1899. Baj ol Labuan Tri ist ol Lombok. On hore.

Bima. * >n shoi

Vpril 16 18, 1899. Baj of Labuan Badjo, V. ist of Flores. On sh<

115. July 9 11, 1 East Side of Pajun I nd. Kwandang Bay. On the <

N.B. Dr. C. 1'n. Sluiter sent me, about 1884, specimens of an Ibla found by liim
at randjong Pandan (Billiton) on corals which belong undoubtedly to this species.]

Genus Scalpellum Leach

( »f all the known genera of Cirripedia this is the richest in species. In liis Monographie
des Cirrhipèdes of 1 Gruvei distinguishes in all 93 species of Scalpellum — that this number

by no means includes all the existing forms is proved by the collection of the "Sib It

contains j8 species of this genus aml 32 of these have not been described before.

This augmentation seems especially considerable, if we take into consideration the relatively
smal! area that lias been explored by the Dutch man-of-war: all these new species were collected
within the Malay Archipelago.

The number >>( species of the present genus hitherto known with certainty as occurrin-;
in that archipelago was sixteen, viz. :

Sc. villosum Leach. Eastern Seas (Darwin) (? India, Timor, New Holland).
N. trispinosum Hoek. Philippine Archipelago.
Sc. rostratum Darwin. Philippine Archipelago.

compressum Hoek. Between Celebes and Sangir Islands.
Sc. album Hoek. North of Karakelang, Talaut Islands.
Sc. hirsutum Hoek. West of Batjan, Last of Celebes.
5 rubrum Hoek. Philippine Archipelago.

truncatum Hoek. Between New Guinea and Australia, East of ('ook Peninsula.
moluccanum Hoek. South of Ceram.

australicum Hoek. Between New Guinea and Australia, East of Cook Peninsula.
. distinctum Hoek. North of New Guinea, eastern half.
indicum Hoek. Kei Islands.

tlu/iiutu 1 1« -ck. Between New Guinea and Australia. East of Cook Peninsula.
\alanoides Hoek. Kei Islands.

inatum 1 loek. /

North ol New Guinea, western half.
\ium Hoi \

55

As

s 17

th

species Sc. rutilum Darwin might be added to this list. Darwin says of this
species that its habitat is unknown and adds: associated with Dichelaspis orthogonia. As the
latter species was collected at three different Stations in the Malay Archipelago, I think it
probable that Sc. rutilum belongs also to the fauna of this region. H.M.S. "Siboga" collected
specimens of three of these species, viz. Sc. ros tra tuin Darwin, which was taken at four different
Stations and seems to be rather a common form in these seas-, .Si:, distinctum Hoek, taken at
two stations and Sc. moluccanum Hoek, which was only collected once. The other 35 species
have been collected in the Malay Archipelago by the "Siboga" for the first time. Two of these,
however, had been observed before outside that Archipelago : Sc. Peroni (Gray) was taken by
the "Siboga" near the Jedan Islands and was known already from the Swan River, Australia
and from Port Western, Bass Straits; Sc. acutum Hoek, collected by the "Siboga" at three
different Stations in the Malay Archipelago, was taken by the "Challenger" in the Atlantic
near the Azores and in the Pacific, near the Kermadec Islands. One of the species of Scalpellum
collected by the "Siboga" closely resembles a species (Sc. Stearusi Pilsbry) occurring in the
Japan Sea: this form is described later as a variety of Pilsbry's species. Thirty two species
remain which I have been obliged to consider as new species.

The following list contains the species collected during the cruise of H. M. S. "Siboga",
with the places were they were collected and the number of the Station, arranged according
to the depth at which they occurred :

Jedan Islands

Bay of Bima, Sumbawa; North of Buton;

West of Saleyer; South of Timor

East of Kei Islands

North of Buton

South-coast of Timor; Bay of Bima, Sumbawa

Sc. Peroni (Gray)
Sc. rostratum Darwin

Sc. pollicipedoid.es n. sp.

Sc. aries n. sp.

Sc. itnais n. sp.

5c. imbricatum n. sp.

Sc. diota n. sp.

Sc. candidum n. sp.

Sc. Stearusi Pilsbry,

var. robusta n. var
Sc. hamulus n. sp.
Sc. polymorphum n. sp.
Sc. praeceps n. sp.
Sc. pellicatum n. sp.
Sc. fissum n. sp.
Sc. p roe live n. sp.
Sc. deforme n. sp.
Sc. curiosum 11. sp.
Sc. crinitum n. sp.
Sc. incertum n. sp.
Sc. chitinosum n. sp.
Sc. poculum n. sp.
Sc. javanicuin n. sp.
Sc. humile n. sp.

Near Kei Islands

Near Kei Islands

Near Kei Islands

Near Kei Islands; Madura-Sea ....
West of Makassar; Kei Islands. . . .

Kei Islands

Kei Islands; North of Sumbawa . . .
Between Halmaheira and New Guinea .

Kei Islands; East of Borneo

West of Halmaheira; South of Celebes .

Near Palos Bay, Celebes

Near Palos Bay, Celebes

North of Sumbawa

North of Sumbawa

Between Kofiau and New Guinea . . .
North of Sumbawa; West of Aru Island

Near Rotti, South of Timor

North of Bali

East of Saleyer

55

(274)

47. 2°4

13—94 m.

213, 294

274

57 m-

204

75—94 m-

285, 47b

34, 296 m.

251

204 m.

251

204 m.

251

204 m.

5. 74
251, 254

204 — 450 m.

256

397 m-

256, 45

397, 794 m.

'59

411 m.

256, 94

397, 450 m.

137, 212

462, 472 m.

87

655 m.

87

655 m.

45

794 m-

45

794 m-

161

798 m.

45- 271

794, 1788 m

300

918 m.

18

1018 m.

21 1

11 58 m.

56

I i ui m.

Island and Waig< u [sland . . ■ 151,

III, 122 II 1 m.

m 1 ">•

South of Ccram; South of Ambon 1 m.

\iu Island m.

! I \ru [sland 27 1 m.

\\ i m.

Northern entrance of Strait ol Macassar; . . . <>o,

I of Buton Islam ram and Mi 1 m.

Vmbon 1 in.

I imor in.

ith "f I imor 1 m.

-14 ni.

Bai da Sea 221 m.

Banda Sea 221 m.

n. sp. Banda Sea 221 m.

ol Scalpellum were thus taken at 32 Stations: two of them (Sc. rostratum
Darwin and Sc. Stearnsi Pilsbry, var. robusta n. var. were collected each al four different
Stations; two of them (Sc. acutum Hoek and Sc. distinctum Hoek) wen- taken each at three
different Stations', six of them (Sc. uncus, Sc. polymorphum^ Sc. pellicatum^ Sc. fissum, Sc.
chitinosum and Sc. formosum were collect ch at two different Stations; all the others

in all) were collected only once. Sonic of the Stations yielded l! species

S alpellum :

at Stat. 45, Lat. 7 :.\ S. and Long. 11N 15. 2 E. Deptli 704 m. Bottom: fine grey mud, with

some Radiolariae and Diatoms, four species of Scalpellum wei . viz. Sc.

chitinosum, crinitum, polymorpkum and curiosum.
at Stat. 251, Lat. 5 28 .4 S. and Long. 132 o'. 2 E. Depth 204 m. Bottom: hard coral sand,

four species of Scalpellum were taken, viz. Sc. candidum, dioia, imbricatum,

and Stearnsi var.
5tat. 2ii, Lat. 5 40.7S. and Long. 120 4;. 5 ]•'.. Depth 1158 m. Bottom: 1 ;rey mud,

superficial layer softer and brown, three species of Scalpellum were taken, viz.

Sc. acutum, humile and gracile.
at Stat. 221, Lat. 6 24 S. and I , , ! . Depth 2798 m. Bottom: solid bluish grey

mud with Foraminiferae, three species of Scalpellum were taken, viz. Sc. disi

hexagonum and sculptum.
at Stat. 256, Lat. .<■ S. and Long. 13 1 . Depth 597 m. Bottom: greyish green

mud. tlt rei- specii alpellum were taken. viz. Sc. Itamulus, polymorphum

and pellicatum.
at Stat. 271. Lat. 5 y ■- .7 S. and Long. 1 | E. Depth 1788 m. Bottom: bluish -reen mud

of a uniform appearance, three species ol Scalpellum were taken, viz. Sc.

moluccanum, chitinosum and inflatum.
at Stat. 7. I at. S. and Long. 119 i'.i E. Depth 655 m. Bottom: fine grey mud, two

of Scalpellum were taken. viz. Sc. proclive and de ferme.
at Stat. 204, Lat. 4 20 S. and Lon - 1 . Depth . m. Bottom: -and with dead

shells, two ellum were taken. viz. Sc. rostratum and artes.

Lat. : ind Long. 122 12 E. Depth n. Bottom: solid 1 mud,

two species of Scalpellum were taken, viz. Sc. distinctum and elegans.

57

at Stat. 227, Lat. 4°5o'.5S. and Long. I27°59'E. Depth 2081 m. Bottom : grey mud with
an upper layer of brown, both mixed with sand, two species of Scalpellum
were taken, viz. Sc. ciliatum and formosutn.

at Stat. 241, Lat. 40 24'. 3 S. and Long. i29°4c/.3 E. Depth 1570 m. Bottom: dark sand with
small stones, two species of Scalpellum were taken, viz. Sc. formosum and
sessüe.
and at Stat. 295, Lat. io°35'.6S. and Long. i24°u'.7E. Depth 2050111. Bottom: fine grey mud,
3 cm. thick, upper layer softer, brown with black stripes, two species of
Scalpellum were taken, viz. Sc. arcuatum and virgatum.

Thus H. M.S. "Siboga" which made collections at 323 Stations in the Malay Archipelago

met with species of the genus Scalpellum at 32 of these, and, while only one species was taken

at 20 of these Stations,

at 2 Stations the number of species found was 4,

at 4 Stations the number of species found was 3,

and at 6 Stations the number of species found was 2.

Naturally, this may be considered as purely accidental ; one feels inclined to admit,
however, that certain places are especially favourable to the life or growth of Sca Ipellu ;;/-species.
That accident plays a great part cannot be denied; most of the species seem to be "rare"
animals and are represented by one or very few specimens only.

Adding the 32 new species collected by the Siboga to the 93 of Gruvel's list of 1904
the number of species of the genus Scalpelhim would now be 125. In his Monograph Gruvel
has given extensive tables for the determination of the known species and I hardly think it ot
any use to give such tables again here. I think it will be possible to recognise the new species
with the aid of the description and the figure ; I point out for each species as a rule what
other species I consider its nearest relation and in what regards the two differ.

Before entering on the description of the different species, a few remarks on the
classification of the genus may be permitted. The classification I have given in my Report on
the "Challenger"-Cirripedia, which afterwards was used and extended by Gruvel, though useful
for the determination of the species, cannot be said to be a good, that is a natural classification.
Such a system should give us, as far as possible at least, a representation of the descent or
origin of the different species.

In 1883 I separated in the first place those species in which the valves were imperfectly
calcified. No doubt the importance of this character has been overestimated by me; I think
now it is of no great use, as there are species with perfectly calcified valves which in other
regards quite resemble those with imperfectly calcified valves; forms even occur with perfectly
and imperfectly calcified valves, which for the rest are so much alike, that they must be
considered as belonging to the same species. This is the case with Sc. Siearnsi Pilsbry and
with Sc. polymorpluim n. sp.

The first question to be answered is which forms are the oldest, the earliest of the
now living species, and I think there can be no doubt that they are those species which, like

57

SIBOGA-EXPEDITIE XXXI <7. 8

Darwin's s like Sc. trispinosutn collected by the " Challenger" and like Sc. pollici-

the *Siboga", have .1 simply keeled, relatively shorl and nearly straight

carina, a sub-carina and a rostrum. The shape of the valves in these species, of the lower whorl

. triangular with the umbo at the apex, i. e. at the extremity opposite to the peduncle.

D l (in 1851), that Sc. villosum "leads on to Pollicipes"; I think he would quite a

that we had better consider that species and those nearly related as derived from Pollicipes.

form of the valves, their number, the occurrence of a sub-rostrum in Sc. villosum 'as in

the no doubt nearly rel. iied Sc. calyculus Aurivillius) the occurrence of two extra valves of the

lower whorl in one ol the specimens of Sc. pollicipedoicles, mihi cf. the description oi that

in the present report are I think so many proofs for the correctness of that theory.

The other forms are considered by me to be derived from the species with a simply

d, straight carina. I think we ought to divide them into three groups which I suppose

d independently from the forms with straight carinae. Calling the place where the umbo

is situated in a species like Sc. villosum its upper extremity, wc see the carina lose its original,

straight form either by adding almost equally at both ends, in which case its shape bccomes

angularly bent; or by growing exclusively downwards, its shape becoming more or less strongly

bowed and its umbo remaining at the apex; or, in the third place, by doing both, that is

adding at both ends, but much more strongly downwards and assuming at the same time the

distinctly bowed shape of the carinae of those species which have this valve simply bowed and

not angularly bent.

From the presence of a sub-carina in most and of a rostrum in all I conclude that the
species with an angularly bent carina are slightly more primitive than those with a bowed carina.
The latter never have a sub carina and in many a rostrum is also wanting '. The structure of
the complemental males shows also that the species with an angularly bent carina are more
like the primitive Scalpellums than those with a bowed carina. Between the two main groups
I place those species in which the carina has an intermediate structure. To this last group
belong most of the species for which I proposed, in niy report of 1883, to create the division
distinguished by imperfectly calcified valves.

We would thus have the following four main divisions :
. /. Species in which the carina is nearly straight with the umbonal part as
a rule projecting freely; a sub-carina and a rostrum are present. Valves
<>f the lower whorl triangular, with the umbo at the apex. The little
males, so far as known, have a capitulum with distinct valves. [Sectio: Proto-Scalpellum\

Number of species of this group at present known: 14. It is represented
in the collection of the "Siboga" by three species : Sc. pollicipedoides n. sp.,
Sc. aries n. sp. and Sc. acutum Hoek.

1 With regard to this valve I wish to point out the following difficulty; ■ t i^inally it always bclongs to the valves of the

1 by the rostral lntcr.il, the rostral margins of the right and left valves touching
l line. S imetimi are slightly hol to wed out in the middle, in which rrow oval-shaped

• til jdacc where the rostrum should 1»-: in that C« whethef a rostrum is present i

•ing the valves — and it is, of course, hetter not to do so in all lh< in which a species is repri

Uic of the rostrum f i'.n purposes i- diminished by this circunistance.

5»

59

B. Species in which the carina is angularly bent, the part above the umbo
equalling or nearly equalling in size that beneath the umbo ; a rostrum is
always present ancl a sub-carina in several species. The little males have

a capitulum with valves and a peduncle, or rudimentary valves. [Sectio: Eu-Scalpellum\

Number of species of this group at present known: i i. It is represented
in the collection of the "Siboga" by four species: Sc. rostratum Danvin;
Sc. Pcroni Gray; Sc. uncus n. sp. ; Sc. Stearnsi Pilsbry, var.

C. Species in which the carina ma)- be divided into two parts : a much
larger part below the umbo and a smaller, sometimes even very small,
above ; a rostrum is present as a rule, a sub-carina never. The little males

have rudimentary valves in a few cases, no valves as a rule. [Sectio : Meso-Scalpellum\

Number of species of this group at present known: 23. It is represented
in the collection of the "Siboga" by six species: Sc. chitinosum n. sp. ;
Sc. inflatum n. sp. ; Sc. javanicum n. sp. ; Sc. curiosum n. sp.; Sc. poly-
morphum n. sp. and Sc. distinctum Hoek.

D. Species in which the carina is simply, as a rule strongly, bowed; a sub-
carina is always wanting, a rostrum often. The little males as a rule

have no valves [Sectio: Arco-Scalpellu/n\

To this group belong all the remaining species of Scalpellum, about 80. It is represented
in the collection of the "Siboga" by 26 species; it may best be subdivided according to the
shape of the carinal latus.

a. Carinal latus with the carinal margin convex and the umbo at the upper extremity, where
the convex carinal margin and the concave upper margin meet at a sharp angle.

Type : Scalpellum velutinum Hoek.
To this division belong about 14 of the known species of Scalpellum; it is represented in
the collection of the "Siboga" by three species: Sc. moluccanum Hoek; Sc. hamulus n. sp. ;
Sc. diota n. sp.

b. Carinal latus with the carinal margin divided into two parts which meet at an indistinct or
obtuse angle. Umbo at the upper extremity where the upper part of the carinal margin
forms an angle with the upper margin of the valve.

Type: Scalpellum sessile n. sp.
Two new species collected by the "Siboga" must be considered as belonging to this
division: Sc. sessile n. sp.; Sc. cilialum n. sp.

c. Carinal latus with the carinal margin divided into two parts which meet at a sharp angle at
the place where the umbo is situated. Upper part of the margin often hollowed out under part
convex, the angle formed by the two parts more or less projecting beyond the line of the carina.

Type: Scalpellum hamatuvi G. O. Sars.
To this division belong about 36 of the known species of Scalpellum: it is represented in
the collection of the "Siboga" by seven species: Sc. discolor n. sp.; Sc. poculum n. sp.; Sc.
arcuatum n. sp.; Sc. imbricatum n. sp.; Sc. crinitum n. sp.; Sc. humile n. sp.; Sc.pellicatum n. sp.

59

latiis with the carinal margin divided into two parts, which meet at an obtuse angle
mtinuous with one another, the umbo being ;u the place where the i«n
part of the margin not, or only very indistinctly hollowed out.
fyi Ipellum formosum n. sp.

|,. this division belong 17 of the known species of Scalpellunt\ it is represented in the
Uection of the " Siboga" bj nine species: Sc. gractle n.sp.\ Sc.proclwen.sp.\ Sc.de/ornti n.sp.;
um n. sp.; Sc. hexagonum n. sp.; Sc. praeceps n. sp.; Sc. elegans n. sp.: Sc.
tip turn n. s|>.; Sp. formosum n. sp.
Carinal latus with the carinal margin not divided into two parts, straight '>r very slightly
hollowed out, with the umbo at the base. where the carinal margin meets with the lias. il
margin. The base of the carina touches, or nearly touches, the upper extremity of the peduncle.
rype: Scalpellum virgatum n. sp.
To this division belong 7 of the known species of Scalpellum ; of these four were collected
by II M. S. "Siboga", viz. : Sc. virgatum n. sp.; Sc. candidum n. sp.: Sc. fissum n. sp. ;
S incertum n. sp.

J. Sectio: Proto-Scalpellum
1. Scalpellum pollicipedoides n. sp. PI. V, fig. 9 — 11.

Valves fifteen, covered by thin and transparant membrane. Scutum triangular, tergum
rhombiform, carina nearly straight with the apex projecting freely. Upper latus irregularly
triangular. Valves of the lower whorl consisting of a rostrum, three pairs of latera and a sub-
carina, all of them small, triangular, with the apices pointing outwards. The little male has a
capitulum with valves.

This curious species is represented by half a dozen specimens.

The capitulum is nearly trapeziform, the occludent and carinal margins running ahnest
parallel to each other. It is rather thick in the under half, tlat in the upper half. The valves
are covered by thin, transparent membrane, and are separated from one another by chitinous
interspaces of a dark-brown colour.

The scutum is rather large; its apex projects bevond the occludent margin of the
tergum and is slightly produced. The lateral and basal margins pass over into one another
quite insensibly, so that the form of the scutum is triangular with a strongly arched basis. The
tergal margin is long, the occludent margin hollowed out.

The tergum is rhombiform and large. The part of the carinal margin above the apex of

the carina has about the same length as the occludent margin, the other part of the carinal margin

rly equals the scutal margin. Near the apex the two terga slightly diverge from one another.

The carina is only very feebly bowed longit.udinally and has the umbo at the apex
which in the largest specimen projects freely. The carina has no flat roof but is laterally bowed
ind : deeply keeled. The width increases from the apex to the base-, the surface is not

■th but feebly, transversely hollowed oüt at five places over its length.

pper latus is small, of triangular shape, with the scutal margin strongly hollowed

6q

6i

out, the tergal and carinal margin confluent and convex, and the basal margins also confluent
and strongly convex.

The rostrum is the largest of the valves in the lower whorl. It projects freely for
about half its length and has the umbo at the apex which is pointed. lts shape is triangular
with the sides hollowed out.

The rostral and carinal latus are of about the same size and shape: triangular,
with the apex projecting from the surface of the capitulum.

The i nfr a-median latus has about the same shape but is much smaller.

The sub-carina much resembles the rostrum; it is slightly smaller however and stands
out in a more horizontal direction.

The peduncle is short, wide at the summit, slightly narrower only at the base. The
calcified scales are very small and not arranged very regularly. They are placed rather close
to one another and extend from the surface as bluntly-conical papillae.

Size. The length of the capitulum of the largest specimen was 4 mm., the total length
6,3 mm. The other specimens are but slightly smaller.

The study of the structure of the hermaphrodite animal contained within the capitulum
has yielded the following results.

Mouth placed near the adductor muscle; elongated in a vertical direction. Lab rum
not very swollen, slightly elongated in a longitudinal direction; crest without distinct teeth;
pal pi minute, triangular in outline, with the apex blunt. Apex and outer margin with rather
numerous hairs.

Mandibles with four teeth and the lower angle delicately pectinated. Two very minute
teeth are inserted in the cavity between the first and the second tooth ; upper side of the fourth
tooth pectinated. Surface of the mandible near the tootheel edge covered with very delicate hairs
placed in groups of two or three; inferior margin clothed with longer hairs.

Maxi 11 ae short and broad; two stronger spines and one or two smaller ones at the
upper end of the edge; a small notch beneath the upper pair and a single spine planted at
its base. The inferior part of the edge forms a sharp angle with the under margin and bears
7 to S pairs of spines. On the outer surface numerous groups of hairs (three or four in a group),
near the spine-bearing edge.

Outer m a x i 1 1 a e rather stout, of oval shape with long bristles on the outer surface.

Cirri. First pair not at a considerable distance from the second. Rami slender and
not very unequal in length. The longest has 8, the shortest 7 segments. Upper segments
slightly narrower than the basal ones; the latter slightly protuberant at the extremity. Spines
relatively long, some of those on the outer segments more than twice as long as the segment.

Second cirrus with rather short rami of 9 segments, lower segments short and broad,
upper segments more elongate; 3 pairs of longer spines on the anterior margin as a rule.

The four posterior pairs with their segments, especially the terminal, much elongated.
The middle segments more protuberant anteriorly than the others. The segments bear as a rule
three pairs of longer spines and a fourth (som'etimes even a iïfth) pair much more delicate on
the front aspect. Dorsal tufts of three or four spines at the extremity of each segment.

61

,u,l. il appendages ttïangular, uni-articulate, small; a tufl <>!" ;il>< <ui hall a dozen
hairs at the extremit)

Penis, rather short, reaching t" il"- extremity of the fifth segmenl of the last pair

rri; its basal part broad with only a feu scattered hairs, the terminal part of about the

same length as th<- basal part, cylindrical, rather narrow, indistinctly ringed. h bears very

ate hairs, which are irregularly distributed over the su ind a rather dense tufl ol

.ii th<- extremity.

The mantle-cavity of the hermaphrodite animal investigated more in detail contained six

rather large and nearly globular eggs. The greatest diameter of the eggs is 0,34 mm., the

shortt t8 mm. They contained larvae in the Nauplius-stage, some of the larvae had partly

I off th<- exuviae

The male <>t" this species is a truc complemental male. I found two of them in th<-
one, one in the other pouch of the hermaphrodite specimen. In fig. 10 the place occupied by
this pouch is indicated as a little swelling [ó). The male is figured PI. 5, fig. 11; its size is
mm. 0,25 mm. It lias six valves: two scuta, two terga, a carina and a rostrum, the
•4rncr.1l shape of which can be seen from the figure. The scutum is the largest, the rostrum
is much broader than the carina. The tergum lias an irregular shape and is divided into two
parts: a larger somewhat excavated at the apex and a very small one at the place of the
primordial valve. Shape and position of the valves resemble the corresponding parts in the male
of Sc. Peroni and Sc. villosum as described by Darwix. But the males of the present species
no narrow peduncle, the capitulum going over quite insensibly into the short and flattened
part to which the prehensile antennae are attached. The membrane connecting the valves is
very slightly rough, but it does not bear distinct hairs. Extremely minute hairs seem to be
planted on the surface near the peduncular pole only. The musculature of the peduncular part
of the sac is strongly developed.

The structure of the little body within the sac corresponds in general but in reduced
condition with that of the hermaphrodite animal as also with that of the males of the nearly
related species Sc. villosum and V. Peroni, It lias ver)- large eyes situated in the median line.
beneath, or rather in front of the strongly developed adductor muscle. The mouth is slightly
bullate; the cirri have but few segments (four in the first, five in the second pair). The penis
is short, cylindrical, rounded at the extremity, where it bears a few curled hairs or bristles.
This specii-, was collected during the cruise of H. M. S. "Siboga" at:

Stat. ^74. December 26, 1899. Lat. 5°28'.2S., Long. i34°53'.9E. Dcpth 57111. Bottom: sand
and shells, stones. 6 specimens.

Observations. This is a very curious species. It belongs to the same group as Sc.

villosum (Leach) and Sc. irispinosum mihi as is shown at once by the shape of the carina.

It has one pair more latera, however, than one of these two species and the general shape of

apitulum is more like a normal Scalpellum in consequence. Like Sc . villosum and trispi-

•n it comes near to Pollicipes, especially /'. sertus and this is particularly the case with

rd to the shape of the valves of the lower whorl.

( me of the specimens shows this relation in a still more conspicuous way and 1 have

62

63

described the discovery of that specimen as an interesting case of reversion in a short note
published by the Amsterdam Academy of Science1. I quote from that paper the following:

Looking over the six specimens of this new species, I was struck by finding that one of
the specimens, though in other regards similar to the other five, differed from them by having
in the lower whorl of valves two latera in addition to the three which all the specimens possess.
In fig. 9, PI. Vs the left side of a normal, in fig. 10 the same side of the abnormal specimen
is represented. (At the right side only one of the adclitional valves is developed.) In fact, the
few small valves which according to Darwin were wanting in the lower whorl of Sc. villosum
to convert it into a Pollicipcs occur in one of the specimens of this new species. By calling it
a case of reversion I would indicate the high importance, which from an evolutionary point
of view I attach to this abnormality. We need not go so far as to consider this species as
representing exactly the "missing link" between the genera Pollicipes and Scalpellum, but I
think the case shows clearly that a form with more numerous calcareous plates in its capitulum
(like Pollicipes) is the older, the form with fewer (like Scalpellum) the younger one; moreover
that the Scalp e Hum -species with straight carinae, inhabitants of shallow water, must be considered
as the oldest, i. e. the species most resembling the primitive form of Scalpellum.

2. Scalpellum aries n. sp. PI. V, fig. 12.

Valves thirteen. Carina straight. Scutum and tergum large. Upper latus narrow, nearly
reachino- the peduncle. Valves of the lower whorl six : a large and prominent rostrum, two
small rostral latera of triangular shape, two narrow carinal latera and a rather strong triangular
sub-carina.

This species is represented by a single specimen only.

The shape of the capitulum is nearly quadrangular with a triangular apex, being
broadest at its lower extremity. The scuta, terga and carina are much larger than the other
valves, the upper latus is medium-sized and of the valves of the lower whorl the rostrum is
the only one that is strongly developed. All the valves stand rather close together and are
not covered by membrane. Their colour is red or reddish, parts of the carina, of the tergum
and the scutum only being quite white.

Scutum oblong, breadth slightly less than half the length, with the upper triangular
portion produced and the apex projecting beyond the occludent margin of the tergum. The
occludent margin is slightly hollowed out, the lateral margin convex.

Tergum large, oblong, elongate-ovate, bluntly pointed at the apex, forming a sharp
ansfle at the lower extremity.

Carina straight with the apex neither directed forward, nor backward; with a laterally
bowed roof, gradually widening from the upper to the basal end, rather deeply concave. The
upper part of the roof is at some distance from the tergum, which distance grows broader
towards the apex, the interspace being filled up by triangular lateral parts.

' K. Akademie v. Wetensch. te Amsterdam, Froceedings of the Sectioa of Sciences, VII, 1905, p. 90.
2 Of the present publication.

63

"I

i triangular, the umbo pointing outwards; laterall) it slightly overlaps the

Rostrum strong and rather large, having the shape of a pyramidal wedge, with the
t(|. prominent beyond the occludent margin of the scutum. Lateral margin nearly straight.

1 the lower whorl two pairs, small, corresponding probably with the rostral

and carinal latera t >t" other ^]»< ■ \. xlpellum. lh<- inferior angle of the pentagonal upper

1 .1 1 u s also meets where they nearly touch one another.

Peduncle wide at the summit, conical, short. Surface with very numerous narrow,
chitinous scales, placed rather far from each other, arranged in regular rows.

I ength "i the capitulum 8 mm., of th<- peduncle ui >< >m 2 mm.

The "Sib illected this interesting form at:

Stat. aepterabei 20, [899. Lat. 4 20' S., Long. I22°58'E. Depth 75 94 tn. Bottom:

sand with dead shells. 1 specimen. (A few specimens of Sc. rostratum Darwin
were found at the same Station.)

General Remark. This curious form belongs to the same group of species as Seal-

. llosum Leach, Sc. trispinosum mihi, Sic. sexcornutum Pilsbry and some of the species

provisionally described l>y Aurivillius and which are all characterised by straight or nearly

straight carinae. In Sc. artes the carina may really be said to be straight; it can be distinguished

:ly from the other species by the number 13) of its valves and by the very characteristic

shape of its rostrum.

3. Scalpellum acutum Hoek. PI. VII, fig. 1.

Hoi k. Cirripedia collected by ll.M.S. "Challenger". 1883, p. 80, pi. III, fig. 19, pi. VIII, fig. 1 _\

This interesting deep-sea species was collected by H. M. S. "Siboga" at three different
5l Lti 'iis. They are very small animals: I measured two, in one the total len<:th was 7,6 mm.,
the length of the capitulum 5,6 mm., in the other respectively 6,5 and 4,7 mm.

I think there can be no doubt, that the specimens are identical with those collected by

the "Challenger". Grüvel1 has described as a new species (Sc. longirostrum) a form of Scal-

pellutn much resembling my Sc. acutum, the main difference being that the carina of the new

species is somewhat broader. My figure ("Challenger" Cirripedia PI. III, fig. 19) represents the

little anima! with the rostral side slightly turned up, so that the carina in the figure looks

narrower than it really is. And my description: "Carina short, simply bowed; sides almost

wantin--, only slightly developed in the superior part" has heen misleading in so far that 1

should have added: a little more so towards the inferior extremity. Of the other differences

points out, the height of the sub-carina, which he says nearly equals that ot" the rostrum

"presque ausM élevée que Ie rostre") and which is much smaller in the "Challenger" specimens

■ in those collected by the "Siboga", is by far the most important. Hut altogether these

diffi only slight: in comparing the specimens with one another they may perhaps

pp r all to be identical.

. du "Travailleur" et du "Talisman". 1902. p. 70.

64

At the end of the description of Sc. longirostrum^ Gruvel in bis "Monographie" (1. c.
p. 58) says that the dwarf males also differ. It is true that I named Sc. actdiim as one of the
species whose males have 110 peduncle, mouth or stomach (Challenger Cirripedia, Anatomical
part, p. 20). However, as I did not observe the male of this species (Ibidem, p. 4), this was
a supposition only and the name of the species, therefore, was placed in brackets. I found little
males (one on each) on two of the "Siboga" specimens and I figure one of them on PI. VII,
in hg. 1. Comparing this figure with that given by Gruvel for the male of Sc. longirostrum,
the main difference is the absence of a peduncle in Gruvel' s and its presence in my figure.
Had my specimen been without a peduncle then I would admit at once that the little stump
had been broken off on isolating the little animal from the female - I dare not say that this
happened to Mr. Gruvel's specimen, but I think it is possible

I consider this species, like Sc. squamuliferwn Weltner and Sc. striatum Aurivillius, as
belonging to the group of Proto-Scalpclliims. The carinae of these species are not quite straight
but they are only little bowed and (with the exception of that of Sc. squamuliferuni) relatively
short. Further, these species have a rostrum and a sub-carina and the valves of the lower whorl
triangular with the umbo at the apex; they have (so far as known) males with a capitulum
with valves and a peduncle. In all these regards the present species corresponds with the others
of this division.

The "Siboga" collected this species at the following Stations:

Stat. 122. July 17, 1899. Lat. i°58'.sN., Long. i25°o'.5 E. Depth 1264 — 1165 m. Bottom:

stone. 2 specimens.
Stat. 151. August [2, 1899. Lat. o°i2'.6S., Long. I29°48'E. Depth 845 m. Bottom: fine grey

mud with coarse particles. 1 specimen.
Stat. 211. September 25, 1899. Lat. 5°4o'.7S., Long. i2o°45'.5 E. Depth 1158 m. Bottom:

coarse grey mud. 2 specimens.

What I said in my "Challenger" publication on the distribution of this species, viz. that
it occurred at places situated very far from one another, has now proved to be true in a still
higher degree: whereas the "Challenger" found it in the Atlantic, near the Azores, and in the
Pacific, near the Kermadec Islands, it has now been observed in the Malay Archipelago.

According to Gruvel the only specimen of his Sc. longirostrum he could investigate was
taken in the Atlantic Ocean not far from the coast of Portugal at a depth of 1923 m.

B. Sectio: Eu-Scalpellum

4. ScalpcUitm rostratum Darwin. PI. V, fig. 13.

DARWIN, Monograph of the Sub-class Cirripedia. The Lepadidae, 185 1, p. 259, pi. VI, fig. 7.

I doubt whether this species has ever been observed since Darwin published his
description. Yet it is perhaps the commonest of the genus under the tropics — at least in the
Malay Archipelago; the "Siboga" collected it there at four different places, 6 specimens in one
haul at two of them, and numerous specimens at a third.

65

SIBOGA-EXPEDITIE XXXI a. 9

I have nothii idd to Darwin's excellent description of t h i-. species, neither for the

hermaphrodite form nor tor the complemental males. Darwin discovered that the latter were

attached in this sp to the integument <>f the hermaphrodite, in a central line, between the

im and the adductor scutorum muscle, three individuals in a group. < tpening the capitulum

specimens I found the little males at once al the place indicated by

>nly difl being that 1 found not three 1 >ut four of them attached t<> the

hermaphrodite. Th< I form of the complemental male and of its rudimentary valves

and scutum are in the main as described by Darwin. The largest specimen measured

to Darwin its length is of an inch = o,8<> mm.). The scutum is

narrow; it is considerably smaller than that in Darwin's figure, but it has exactly th« 0,2 mm.)

which it should ha> irding t" Darwin's description. The whole of the sar, which represents

ombination of capitulum and peduncle, is covered with very minuut hairs. Beneath the

rudiment rina and down the peduncular part of the sai are planted numerous much longer

spines which to a large extent are bifid at the extremity. The fig. 13 of PI. V has been

drawn with the camera from the largest of the specimens.

Darwin's specimens were from the Philippine Archipelago, Island of Bantayan, attached
to a horny coralline: 20 fathoms (about 36111.). The "Siboga" collected it at the followingpla

Stat. 47. April 8 — 12, [899. Bay of Bima (North Coast of Sumbawa). Depth 13 — 55 m.

Numerous specimens.
Stat. 204. September 20, [899. Lat. 4°2o'S., Long. I22°58'E. Depth 75 — 94111. Bottom: sand

with dead shells. 2 specimens.
Stat. 213. Sept. 2 I >t. 26, iSyy. Saleyer anchorage and Surroundings. Depth down to 36 ra.

Bottom: coral reefs, mud and mud with sand. 6 specimens.
Stat. 294. January 23, 1900. Lat. 10° 12.2 S., Long. i24°27'.3 K. Depth 73 m. Bottom: soft

mud with very fine sand. 6 specimens.

5. Scalpellum Peroni (Gray). PI. V, fig. 14, 14.-/, \\B.

Smiliutn Peronii J. E. Gray, Anaals of Philos. New series, X, 1825.
Scalpellum Peronii Darwin, Monograph. Lepadidae, 1S51, p. 264, pi. VI, fig. 6.

I refer to this species the specimens of Scalpellum which were collected by the scientists
of the "Siboga" Expedition at the Jedan Islands. Most probably the place where they were
found is the anchorage off Palu Jedan, east coast of Aru Islands Pearl Banks

There are in all three specimens, one of which is extremely small. The largest one has
been figured; it has a total length of 22 mm. and a capitulum of 13 mm. It is considerably
smaller than the specimens investi^ated by I)\k\vin, which had a total length of little more
than <>ne inch (25,4 mm.) and the capitulum of which measured about three epiarters of an inch
1 mm.). Perhaps the differences between the description and li-nre given by Darwin and the
from Jedan must be ascribed to the circumstance that the latter specimens are not
quite full-grown.

These differences are in the- first place, that the spines which clothe the membrane

the valves and the interspaces are by no means so strong and se. dense as they are

figure given by Darwin; and secondly, that the rostrum and the subcarina,

6;

which are figured by. Darwin as freely projecting beyond the rostral and carinal margins of the
capitulum, are much less strongly developed and hardly projecting in the specimens from Jedan.
So far as I know this is the first time, that specimens of this species have been collected
since the publication of Darwin's Monograph. He knevv the species from specimens found in
the Swan River, Australia, attached to a coralline, and from Port Western, Bass Straits
(Astrolabe Voyage) : the Swan River is on the west side of Australia, Bass Straits on the south.
The Jedan Islands, the third place where the species occurs, lie between the north of New
Holland and New Guinea. [Gruvel \ found three specimens of Sc. Pcroni in the collections
of the Paris Muséum d'histoire naturelle; but their habitat is unknown. He pointed out that
these specimens are not covered by a complete coating of fine and numerous hairs as in
Darwin's description and figure].

6. Scalpelhim iincus n. sp. PI. V, fig. 15; PI. VII, fig. 2, 3.

Valves thirteen. Carina ancjularly bent with the umbo in the middle of its leneth.
Rostrum rather large. Three pairs of latera. Upper latus pentagonal. Sub-carina pyramidal,
standing out bevond the surface of the carina.

Of this species there are three specimens representing two different forms.

The capitulum is fiat, broad in the middle, the upper part slightly produced. It has
1 3 valves with narrow, but distinct intervals. The valves are not covered with membrane in
the one (Station 285) and are covered by a resistant and pigmented membrane in the two
other specimens (Station 47b).

Scutum middle-sized, with the upper end pointed; nearly quite flat; lateral margin
near.ly straight, parallel with the occludent margin. In the specimen without membrane a distinct
swelling is visible at the place where, on the inner side, a pit is present for the adductor muscle.
Basal margin composed of a longer and a shorter segment, making an angle with one another.

Ter gum large, triangular, flat. Occludent margin distinctly convex towards the apex
which is recurved ; carinal margin projecting a little above the apex of the carina ; scutal margin
slightly convex.

Carina bowed, laterally strongly compressed, and thus internally deeply concave ; upper
portion above the umbo nearly as long as the part beneath the umbo ; roof laterally convex
growing wider from the umbo downwards and indistinctly separated from the parietal parts
of the valve.

Upper latus pentagonal, with the apex rounded and the umbo at a short distance
from the apex.

Rostrum of considerable size, internally concave; outline of the upper portion triangular,
of the lower portion trapeziform. The umbo is at the apex, which, especially in the specimens
covered with membrane, slightly projects beyond the occludent margin of the capitulum.

Rostral latus very thick and solid, large, irregularly pentagonal, with the umbo near
the rostral margin and near the base of the valve and distinctly projecting outwards.

1 GrüVEL, A., Révision de» Cinhipèdes. Nouveil. Archiv. d. Muséum. (IV). IV, 1903, p. 234.

67

I arinal latus elongated pentagonal, narrow, with the umbo about in the centrum
of di htly projecting outwaï

arina small; solid, pyramidal, standing oul beyond the surface of the carina.
Peduncle about half the length of the capitulum, rather narrow, narrowest aboul the
middle of its length; surface with minute chitinous scales standin ome distance from one

ther. In one of the membram .1 specimens of Station 17 the length of the peduncle

is more than half the length of the capitulum.

Si. 1 Length of the capitulum 0,1 mm., of the whole animal 13 mm. in the specimen
Station 285; in the largest specimen hom Station 171, the corresponding dimensions are
.n.1 1 3,8 mm.

< omplemental males. Two complemental mal'-, were observed in one <>l the

mens from Station 47 attached to tin- surface ol that part ol the sac or mande of the

hermaphrodite animal which unites the inferior halves of the two scuta. These males are relatively

. the longest diameter of the body being <>.ei mm. Their shape is elongated oval and the

is divided into a larger capitular part and a very short peduncle. The capitulum has six

valves: 2 scuta. 2 terga, 1 carina and 1 very large rostrum. Fig. 3 of PI. YII has heen drawn

from the male of this species; it has a great resemhlance to the male of Sc. Peroni and, no

doubt, that of several other shallow-water species.

This species was collected by II.M.S. "Siboga" at two Stations, viz. at:

47. April u, 1 19. Entrance to Bay of Bima (Sumbawa). Depth 296 m. Hottom: fine

sand with mud (coral). Two specimens. One of tliem was attached to .1 small

k, t'> which a piece of coral was also attached.

Stat. 285. January [8, [900. Lat. 8° 39'.! S., Long. i27°4'.4 E. Depth 34 m. On the limit betwecn

mud and coral, Lithothamnion. (Anchorage south-coast of Timor). One specimen.

1 (bservations. The present species coines nearest to Sc. Peroni of the known species,
e. g. in the number of valves, the shape of the carina and the form (nol the size) of the tergum.
It differs from it by the absence of the fine spines which cover the membrane in Sc. Peroni,
by the valves not being separated by rather wide interspaces of membrane and in the third
place by the shape of the latera.

At first I considered the specimen from Station 285 (PI. YII, 1'i^. 2) without a distinct

membrane as being different from the specimens from Station 471' (PI. Y, fig. 151. which are

covered with a very conspicuous membrane. Looking at the shape of the capitulum and at the

form of the different valves more closely, 1 became convinced, however, that there was no

reason to consider them as specifically distinct. It is truc that they were taken at very different

depths; l.ut other species also range over depths of rather great difference. Thus, for example,

ulgare Leach observed in very shallow water and also at a depth of 07 m. For this

I 1 1 has described a very characteristic case of polymorphism, corresponding in many

to what I found in Sc. umus, viz. that specimens of different localities 'and depths

in the development of the membrane covering the valves, of the interspai

■ dves, as also in the -rade of calcification, the hairiness of the membrane etc.

■ lies \ii hives du Muséum. 1\ IV, i

69
;. Scalpellum Steamsi Pilsbry var. robusta and var. gemina n. var. PI. VI fig. i — 12.

Scalpclluni Steamsi Pilsbry is a shallow-water species from Japan. It was described for
the first time (1890) by Pilsbry1 and a year later by Fischer 2 (as Sc. calcariferum). Both
Weltner (1. c. p. 250) and Gruvel (1. c. p. 44) consider the species of Fischer as synonymous
with that of Pilsbry, and comparing the figures there can be no doubt that they are rio-ht.

In the Malay Archipelago H.M.S. "Siboga" collected at different Stations and at depths
varying from 204 — 450 m., specimens of a Scalpelluiu-species, which at first sight showed oreat
resemblance with Pilsbry's Sc. Steamsi. I have been long in doubt, whether they belono- to
that species or not. The result of a careful comparison of the specimens of the Malay Archipelao-o
with one another and with a specimen from Nagasaki (Japan) has been, that I do not consider
them as specifically different, but that the animals collected by H. M. S. "Siboga" must be
regarded as two varieties of Pilsbry's species.

I give in fig. 1, PI. VI, a figure of Pilsbry's Sc. Steamsi from a specimen collected by
Lischke near Nagasaki which belongs to the collections of the Berlin Museum of Natural
History 3. It was in dry condition but it corresponded in all regards with the descriptions and
figures given by Pilsbry and Fischer. The varieties robusta and gemina differ from the Japan
species in several regards as will be shown.

a. Scalpellum Steamsi, var. robusta. PI. VI, fig. 2, 3, 8 — 12.

The variety robusta differs at first sight by its much more plump, robust shape and by
the length of its peduncle. The Japan form has the capitulum more elongated, its length
measured along the occludent margins of scutum and tergum being equal to one and a half
times the breadth ; the apex of its tergum is produced ; the length of the peduncle is nearly
the same as the breadth of the capitulum and is by all means considerably shorter than the
length of the latter. In the variety robusta the length of the capitulum is only once and a third
its breadth ; the apex of the tergum is not produced and the peduncle is considerably longer
than the capitulum.

The shape of the different valves in the variety robusta is not very different from that
in the original Japan species. Yet the upper latus and the infra-median latus are both considerably
broader in this variety and this is also the case with the tergum. The latter valve has the
apex and the angle formed by the carinal and scutal margins blunt.

As in the Japan specimens the marginal parts of the valves are not calcified: if the surface
is thoroughly cleaned with a brush, the calcified portion which is white, is easily distinguished
from the chitinous marginal parts which border the valves. In the Malayan specimens, however,
the calcified portions are not at the surface, the whole valve being covered by a rather thick
chitinous coating. Whether this is also the case in the shallow-water form from Japan I cannot

! Pilsbry, H. A., Description of a new Japanese Scalpclluni. Proceed. Acad. Nat. Sci. Philadelphia. iSgo. p.441 — 443. (Sc. Stearnsi).

- Fischer, P., Description d'une nouvelle espèce de Scalpellum du Japon. Bullet. de la Soc. Zoolog de France. XVI, 1891,
p. 116 — IiS. (Sc. calcariferum).

3 The director of the Museum, Prof. Karl Möbius, and the Keeper of the Cullection of Crustaceans, Dr. W. Weltner, made
the study of these specimens easy and agreeoble to me.

69

the specimens I have been able to in. in dried condition and did m>t show

this

In the specimens of the variet) robusta^ the chitinous membrane is developed very
stro; the line separating the capitulum from the peduncle; here it forms a cushion-like

swelling over the basal portions of the valves of the lower whorl. The very long peduncle
markable characteristic of this variety. All the known species of Scalpellum have
rather short peduncles, the longest 1 have seen being that of Sc. Darwini mihi, which measures
• >t" the length of the capitulum. < 'f the three specimens "l tin- variety robusta^ <>ne is
considerably smaller, most probably not full-grown (this specimen is figured PI. VI, fig. 3; its
capitulum i- mm. long, its peduncle 2^ mm.); the other two seem t.> In- full-grown:

the length of the capitulum is .|S min. in the one and 52,5 mm. in the other specimen.
the length of the peduncle is 92 mm. in the one and 73 mm. in the other specimen.

1': and Fisi m R both give figures of this species representing specimens at their

natural si/e. Pilsbry says in his description that the peduncle is long and his figure represents
it about as long as the capitulum, which is already a fair length for a species of Scalpellum ■,
Fischer's figure shows the peduncle cut off transversely, only slightly longer than half the
length of the capitulum; in his description he says nothing about the length of the peduncle.
In the two specimens from Nagasaki I was able to investigate, the dimensions of the capitulum
and peduncle are as follows:

the length of the capitulum is 48 mm. in the one and 44 mm. in the other specimen,
the length of the peduncle is 30 mm. in the one and 14 mm. in the other specimen.

There are moreover in the variety robusta very characteristic and very prominent rings
on the surface of the peduncle. The rather large scales are placed in rows which project freely
over the surface as so many hoops and are separated from one another by rather deep circular
grooves. The specimen of 48 mm. capitulum-length has about 40, the other about 33 such
rings on the surface of the capitulum. They are very distinct on the peduncle of the smaller
men of the variety robusta also, but their number is there only 14.

There are in the "Siboga" collection three specimens in all which I consider to belon-
to this variety. Thej were caught at three different Stations, viz.

Stat. 5. March 10, 1899. Lat. 70 4.6 S., Long. 114" 50.5 E. Depth 330 m. Bottom: mud.

Large specimen, figured PI. VI, tig. 2.
Stat. 251. December 8, 1899. Lat. 5°28'.4S., Long. 1 J2fl 1 » .2 E. Depth 204 m. Bottom: hard

coral sand. Large specimen attached to a piece of shell, which bears numerous

tubes of tubicolous Annclids on its surface.
Stat. 254. December n Lat. 5 4.0'S., Long. [32 26 E. Depth 510111. Bottom: fine,

grey mud. Small specimen, figured PI. VI, fig. 3.

b. Scalpellum Stearnsi, var. gemina.

variety gemind has imperfectly calcified valves. In the Japan species and in the

usta the valves with the exception of the marginal portions are perfectly calcified,

the portion having the shape of the valve itself. In the variety gemina the calcified

7i

portions of the scutum, tergum, upper latus, and infra-medïan latus have a shape of their own,
which can be made out only by separating them from the chininous covering by means e. g.
of caustic potash.

The figure 4 of PI. VI represents this variety and illustrates another peculiarity of the
specimens caught by H. M. S. "Siboga"; the four specimens form two couples of two : in the
pair figured both specimens are attached to one another and at the same time to the long
silicious needies of a sponge; in the other couple the one is attached to the extremity of the
peduncle of the other. The shape of the calcareous portions can be distinguished through the
chitinous membrane which covers almost the whole surface; very small parts of the scutum near
the angle formed by the occludent and tergal margins, and of the tergum near the angle formed
by the occludent and carinal margins, remaining uncovered. At these places, where the umbones
are, the surface of the valve is quite white and opaque, the chalk being quite amorphous ;
the rest of the valve appearing blueish, more or less transparent and crystalline. Naturally, this
difference can be seen best after isolating and cleaning the calcareous valves (PI. VI, fig. 5).
The peduncle of this variety is longer than the capitulum ; it is not so long, however, as in the
var. robitsta. In the four specimens I was able to investigate, the dimensions were as follows:
Specimen 1. Length of capitulum 471/.' mm. Length of peduncle 60 mm. Number of rings on

peduncle ± 48.
Specimen 2. Length of capitulum 49 mm. Length of peduncle óo1/? mm. Number of rings on

peduncle ± 49.
Specimen 3. Length of capitulum 45 mm. Length of peduncle 56 mm. Number of rings on

peduncle ± 40.
Specimen 4. Length of capitulum 45 mm. Length of peduncle 481/.. mm. Number of rings on
peduncle ± 48.

The rings- formed by the scales on the surface of the peduncle are not so prominent
as in the variety roónsta, they are still, however, very conspicuous. The peduncle as a whole
is stout and cylindrical — it looks like a piece of rope.

This variety was collected by H. M. S. "Siboga" at one Station only, viz. :

Stat. 74. June 8, 1899. Lat. s° 3-S S., Long. U9°E. Depth 450 m. Bottom: Globigerina ooze.
Four specimens: two couples of two.

In the descriptions of Pilsbry and Fischer, details on the structure of the animal's body
are wanting. I studied some of the peculiarities with the aid of one of the specimens of Station 74.

Mouth. Labrum not very bullate with a strongly developed, anteriorly projecting part
which is triangular and pointed at the extremity; crest with a few extremely minute triangular
teeth. Palpi elongate, about three times as long as broad, densely beset with hairs towards
the extremity and along the internal margin.

Mandibles stout with four teeth and the inferior angle. Between the first and second
teeth two much smaller ones are observed, making the number six, if these are also counted.
Inferior angle blunt, indistinctly pectinated (PI. VI, fig. 7).

71

Maxillae with a long, sinuous edge and a great number of nearly equal spines. Thi
at the upper corner are slightly larger and another group of the larger spinee is planted al
•sli the height from the inferior angle. The apodeme is stout and nol very long.
Outer maxillae are well-developed with the bristles of tl irly straight inner

[in divided int<> two separate tufts, separated from one another bj ;i little excavation without
irly they are swollen and not ver) densely beset with bristles. The opening
leading into the 1 rity is large and situated on the top of a rounded protuberance.

I ■ ■. 1 irst pair short and very stout; rami not very unequal in length; much m
so in the number of segments, and especially in breadth PI. VI, fig. 6). The anterior segment
nine, the posterior ^i\t««n segments. I In- segments of the anterior ramus are oblong in
iverse direction and are only united with one another over pan ol the breadth; the segments
of th( • rior ramus are as broad as they are long, with the exception <>|' the first segment

which is longitudinally oblong. In both rami the segments ln-ar numerous spines along l
margins, the outer seerments over the whole surface.

nd-sixth cirrus differ trom one another mainly in length; this difference is
greatest between the second and third cirrus. In the second cirrus the anterior ramus is mon
a little broader than the posterior ramus. in the other cirri this difference does not exist. All
the cirri give one the impression of being stout and well-developed.

1 audal appendages small, composed of six cylindrical segments, the width of which
diminishes considerably from the first to the last; each segment bears a few very delicate bristles
at the extremity; the last segment has aboul hall' a dozen longer ones on the rounded u]

Sex. The specimen investigated showed no tracé ol male ^cnital organs : neither

testicula nor penis; I think this species must be considered as belonging to the group of

exual species of which I discovered several representatives when studying the Cirripedia of

the "Challenger" expedition. The specimens the description of which is given above were

probably all femali

Mal es. At first I could not find the males of this species. At last I found them on the

specimen of Station 5: very small bead-like individuals attached in great number to the

surface of tliat part of the sack <»r mantle of the female which connects the inferior halves of

the two scuta at their occludent margin. I counted well over a hunderd of these little animals.

Each of them is enclosed in a chitinous sack and are placed so near one another as to to

and even to (latten each other mutuallv. Fig. 9, PI. VI represents a group of three of them-,

in fig. 8 one of them is seen a little more enlarged. They are attached to the outer surface

of the chitinous sack of the female with their small antennae, and their surface is hirsute with

very short spines. The opening giving entrance to the interior of the sac is at the top of a

conical papilla which projects beyond the surface of the remaining part of the sac Round

ing are four very small calcareous parts like so many rudimentary valves and between

. small 1 ences with short hairs, like minute tentacles, are planted. 1 have not been

able to study the internal structure which can be done by making microtome sections only

but I observed the testiculum and the receptaculum seminis in several specimens. The longest
diameter of the specimen of fig. 8 measured 0,66 mm., the shortest about 0,5 mm.

I observed a few (3) males of exactly the same shape and structure and at the same
place in one of the specimens of the var. gemina from Station 74, and I think the fact that
they are wanting in the other specimens must be considered as the consequence of the season
or age. While studying the Cirripedia of the "Challenger" more than 20 years ago, I discovered
that the larvae of Sc. Stroemi develop into the Cypris-stage before leaving the egg-membrane.
Whether all the eggs did so could not be made out; but that there are Scalpellums which
develop without a free-swimming Nauplius-stage cannot, from that discovery, be doubted. One
might suppose, that only the complemental-males (or the clwarf-males in the unisexual species)
had such an abbreviated development. It seems probable, however, that there are several among
the deep-sea species whose females as well as males develop without passing through a free-
swimming Nauplius-stage. I conclude this from the fact, that I found half a dozen very small
specimens (females and males) attached to the surface of the scutum of the large female Scal-
pel! um which was collected at Station 5. Darwin speaks of the male larva of Sc. vulgare
"crawling on the scuta of the hermaphrodite" and of discovering the fold in the shell where
it invariably attached itself: that males should be found on the scutum is not at all surprising,
but for the females it would be different, unless it be that they do not swarm out, but creep
from the cavity of the mantle in the cypris- or so-called pupa-stage.

That the little Scalpellums I found attached to the outer surface belong really to the
same species admits of no question. I figure one of these small animals PI. VI, fig. 11, and
the tip of the capitulum more strongly magnified in fig. 12: the capitulum has exactly the same
tentacular appendages which I observed in the males and about at the same place with regard
to the primordial scutum and tergum. What the physiological meaning of these tentacles is, is
difficult to say; they are larval organs which the females seem to loose and which the males
keep in mature condition. Morphologically these tentacles are no doubt also of importance —
by all means they render us the good service of enabling us to demonstrate that the little
females attached to the fullgrown specimens belong to the same species as the dwarf males
attached to the mantle-surface between the two scuta.

C. Sectio: Meso-Scalpellum
8. Scalpclluiu chitinosum n. sp. PI. VII, fig. 4.

Valves thirteen, covered by chitinous membrane. Scutum and tergum imperfectly calcified.
Carina with the umbo at some clistance from the apex, angularly bent. The part beneath the
umbo strongly bent. Upper latus quadrangular, broad with the apex produced in the direction
of the scutum. Upper part of the infra-median latus broad triangular. Umbo of the carinal latus
at the base, projecting bevond the line of the carina. Rostrum wanting or not calcified.

The collection made during the cruise of H. M. S. "Siboga" contains two (perhaps 3)
specimens of this species.

The capitulum is fiat and very broad, the length being less than one and a half

73

SIBOGA- EXPEDITIE XXXI a. IO

times the breadth. I cludent and carinal margins are both strongly convex. The whole

tpitulum by a chitinous membrane, with the exception only of the apex of the tergum.

ves is mostij very indistinct: though the largesl specimen of Station 45
ired the shape of the latera is much more distincl in the smaller specimen of the

Station Hence f<>r the description of these valves the smaller specimen has been mostly
mai

The scutum lias the occludent margin convex and the tergal margin slightly hol lo wed

out. The calcified part is formed of two segments united at the apex: the one the occludent

ider ai the base and narrower towards the upper extremity; the other the

ter nds along the tergum, is very narrow and shows the same width over its

whole length.

Tl um has the calcified part V-shaped: a shorter and narrower occludent segment

and a slightly broader and longer carinal segment having their point of junction al the apex of
the valve. Along the occludent segment the chitinous covering forms a cushion-like investment,
the free margin "I" which is stronglj arched. The apex of the tergum is recurved, bent towards
the carinal side of the capitulum.

The carina has the umbo at some distance from the apex. The part above the umbo
is quite covered by the chitinous membrane. the roof of the part underneath the umbo is covered
by a thin membrane only. hs width increases distinctly, but not very strongly from the umbo
downwards; its margins develop int<» distinct ridges. The sides are rather broad especially in
the uppermost part; its limits cannot, however, be made out distinctly.

The upper latus is broad, trapeziform, the tergal and basal margins running about
parallel to each other. The scutal margin joins the tergal margin in a rounded or truncated angle
which extends t<> the extremity of the tergal segment of the scutum. The umbo is near the apex.

The rostral latus is narrow or low. The basal margin is shorter than the scutal
margin, the lateral margin slightly convex. The rostral margin of the two rostral latera only
meet one another at the upper extremity. A triangular space remains between the two vah
which is covered by chitinous membrane only: this is most probably the place for the rostrum
if it wi ent as .1 calcified valve.

The infra-median latus has the umbo near the base. Its general shape is that of
a tall win< almost without stalk, with a smal! and narrow foot and the upper part wide.

The carinal latus has the umbo at the bas.-, projecting beyond the line of the carina.
The carinal margin is strongly hollowed out; further, there can be distinguished a short and
straight upper margin, a slightly hollowed out lateral margin and a somewhat convex basal margin.

The peduncle is cylindrical, compressed laterally. The scales on the surface are rather
broad but not very prominent. They are numerous but they are not placed in regular longi-
tudinal n.v.

Size. The size of the largest specimen was 28 mm total length and 21 mm. length of
pitulum.

! the specimens is attached to a little piece of the shell of a Gastropod mollusc,
the other to a small black stick the nature of which is unknown to me

71

75

The study of the structure of the animal contained within the capitulum has yielded the
following results :

Month. Lab rum not very bullate, triangular when seen from above-, teeth hardly
distinguishable. Pal pi rather elongate with a tuft of hairs at and near the extremity.

M a n d i b 1 e s with three teeth equally distant from one another ; the inferior angle blunt,
with half a dozen small indistinct teethlike nobs. Hardly any hairs on the surface of the mandible.

Maxi 11a e with three stronger and one small upper spine and a notch between these
and the other spines. The notch is more distinct on the maxilla of the left side. The straight
part of the edge beneath the notch bears 7 or 8 spines, which are all of them smaller than
the three upper spines. The surface of the maxilla bears very few and very delicate hairs on
the part near the edge only. The apodeme is long and flat at the extremity.

Outer maxillae with the inner margins covered with hair-like spines and the openings
leading into the body cavity at the extremity of long tubular projections.

Cirri. First pair much shorter than the five posterior pairs, seated at a little distance
from the second pair. The rami of the first pair are unequal in length and breadth : the shorter
has 8 segments which are oblong in a transverse direction, the longer ramus has 12 segments
which are about as long as broad. The segments of the posterior cirri are elongated, the cirri
strongly curved. I counted 32 segments in one of the rami of the last pair.

Ca u dal appendages with 8 segments-, each segment bears a few very delicate hairs
on the inner side near the extremity, the segments 5 — 8 bear moreover a very long spine-like
hair on the outer side near the extremity and the broad extremity of the 8lh segment supports
six of these.

Dwarf males. I found six of them in the pouch on the inner side near the extremity
of the left scutum; there are several in the pouch on the right side also, but I left them intact
so as not to damage the specimen more than was necessary. The males have the same shape
as in the nearly related species : Sc. javanicum etc. The shape is oval, but as the peduncular
extremity is slightly thicker, the whole is somewhat pear-shaped. A rather large and very
distinct opening leads into the cavity of the sac. The surface is covered with short, spinelike
hairs, which are larger and more numerous at the peduncular pole. No tracé of calcareous plates
or valves. The longest diameter of one of the males was nearly 1 mm. (0,93 mm.).

The species was dredged at :

Stat. 45. April 6, 1899. Lat. 70 24' S., Long. ii8°i5'.2E. Depth 794 m. Bottoin : fine grey
mud. Tvvo specimens.

Observations. At Station 271, December 21, 1899; lat. 5°4ó'.7 S., long. i34°o'E.;
depth 1788 m.; bottom green mud, a specimen of a Scalpellum-s^&aes was collected (together
with three specimens of Sc. infiatum, mihi) which I think belongs also to the present species.
It was found attached to a piece of pumice-stone and it seems to be a slightly older specimen,
lts capitulum measures 27 mm., its peduncle is short and has a length of only 10,5 mm. The
form of the capitulum and that of the valves corresponds with that of Sc. chitinosum, but the
chitinous membrane covering the valves is considerably less thick : in consequence the shape
of the valves can be made out much easier. The most marked difference I discovered is, that

75

7"

tl)t- na is quite ilat in this specimen, thcn being hardly .1 tracé "I the longitudinal

khich are distinct in the specimens ol Station r This difference, however, is not considered

cient importanci t" separate from one another forms which quite correspond in

other regards. Another difference is given b) the two rostral latera which meel in this specimen

the whol( th «'t the rostral margins, .1 rounded space in the middle ol this margin

onl) remaining uncovered l>\ calcareous matter. \ rostrum, however, could not be said to be

.ent in tliis specimen eith

N \lpellum um 11. sp. PI. VII, fig. 5 and 5a.

Valves fourteen. Capitulum bulky, swollen, covered b) .1 thick chitinous membrane.

Membranous interspaces between tin- valves. Umbo of the carina ai some distance from the

valve angularly bent in consequence. Scutum and tergum imperfectlj calcified and

divided into two parts by a prominent ridge, their occludent margin strongly convex. Si. les

of tin- carina broad; upper latus pentagonal; infra-median latus elongated with the umbo near

the base; carina] latus with tin- umbo near the base. Rostrum quite covered by membrane.

This species is represented by three specimens. It is without doubt nearly related to

ompressum^ mihi, collected by the "Challenger". lts bulkiness, the structure and imperfect

calcification dl' scutum and tergum distinguish it at once from tin; "Challen^er" species. '1'he

specimens were covered with mud; the outlines of the valves could only be made out alter

the surface with a brush.

The capitulum is relatively short, about one and a half times as long as broad, also
thick. swollen: its thickness is about IO mm. in a specimen the capitulum of which measures
17,5 X 27 mm. The thick chitinous membrane which covers the valves and the interspaces
between them, leaves uncovered the umbonal part of the scutum and the tergum. This chitinous
membrane is very characteristically pigmented on some of the valves, the scutum especialiv.
The chitinous interspace between the valves is particularly broad between the carina and the
other valvi

The outline of the scutum is quadrangular, it is stromdv bowed in transverse direction.
i occludent margin is convex; where it reaches the tergum a recurved apex is formed which
overlaps a pan of the tergum. The calcified pan consists of an elongated occludent and a
short and narrow tergal segment.

The tergum is rather quadrangular than triangular. lts occludent margin is stronglj
convex forming with the concave uppermost pari of the carina! margin a distinctly recurved
apex. The- scutal margin is nearly straight, the undermost part of the carinal margin which
forms the fourth margin of the quadrangle is also straight. The calcified part of the tergum
is V-shaped and is composed ol a broader occludent and a slightly narrower carinal segment.

The carina lias the umbo at some distance trom the apex and the part above the
umbo forming an angle with the part underneath it. A rooi, slightly hollowed out longitudinally
and growing rather wide towards the base of the valve, can be distinguished from the sid< -
h are narrow at the base and ol considerable width in the uppermost part.

7"

77

Rostrum (hg. 5a) small, triangular, totally covered by thick chitinous membrane.

The upper latus is pentagonal with the sides of unequal length : the basal margin
separating it from the infra-median latus is the shortest, the tergal margin the longest. The
umbo is seated at a little distance from the apex.

The r o s t r a 1 latus is trapeziform : the scutal and basal margins run parallel, the lateral
margin is convex and the rostral margin also slightly arched. The upper halves of the two
rostral margins limit a small triangular space which is occupied by the rostrum.

The infra-median latus has a triangular basal part and an elongated triangular
upper part. Where the two parts unite the umbo is seated. The lateral margin of this valve
can not well be made out; most probably, it is slightly concave.

The carinal latus is quadrangular. The carinal margin is hollowed out, the umbo is
seated at a little distance from the base. The basal margin is short, the lateral margin feebly
arched, the upper margin short and straight.

The peduncle is cylindrical. The scales are narrow, laterally more strongly developed.
They are placed on six longitudinal rovvs : one rostral, one carinal and on both sides two lateral
rows. In the specimen figured there are about 9 scales in each longitudinal row.

Si ze. The specimen figured is the largest of the three. lts total length was 45 mm., that
of its capitulum 27 mm. One of the specimens was found attachecl to a rounded piece of very
porous stone, most probably pumice-stone, the two others to a specimen of Sc. moluccanum,
the only one collected during the cruise of H. M. S. "Siboga".

The study of the structure of the female animal contained within the capitulum has
yielded the following results :

Mouth bullate, same shape as in the other nearly related species. Second maxilla
with the openings giving entrance to the body cavity at the end of long and fiat tubular projections.

The first cirrus has both branches short, broad, rlattened ; the anterior branch
considerably broader than the posterior. The second cirrus is placed at a little distance
from the first with longer, cylindrical rami; the cirri of the four last pairs have very long and
strongly curled rami.

The ca u dal appendages have six segments, the last one is abruptly cut off in a
transverse direction and bears numerous hairs on the extremity.

No tracé of a penis; I consider the large animals unisexual and female, the males as
dwarf-males.

Four dwarf-males were found in the left pouch formeel by a duplicature of the sac
or mantle, at the inner side of the scutum in front of the adductor muscle. There are several
in the right pouch also, but I could not count them without loosening the pouch from the
scutum. The size of the males is 1 mm. in length and about 0,6 mm. in breadth ; shape oval.
Opening giving entrance to the sac at the capitular pole. The prehensile antennae are attached
to the little body about the middle of its length. The whole surface bears minute hairs ; they
are longer and stouter, however, at the extremity opposite the capitular pole. A few longer,
but very delicate hairs form a tuft, one at each side of the mantle- or sac-opening. The male
corresponds on the whole in shape and structure with that of Sc. javamcum, Sc. curiosum etc.

77

7S

H. M. S - oll< cted ihis sp ,t

Stat. 271. Dcccmbei 21, Long. 1 340 o' 1 Depth 1788 m Bottom: bluish

. 11 mud "i unifoi m appearai

(i itions, rhis species comes without doubt very near to Sc. compressum, mihi,

the main difference being that the scutum and tergum do not show the prominent ridge

teristic of the "Challenger" species and are imperfectl) calcified. I think it possible,
however, that these differences may turn out to I"- of less importance than we now think. it
we '>nl\ had .1 richer material at our disposal. Sc. compressum was collected in the Celebes Sea

depth of about 391 10 in.

10. Scalpellum javanicum n. sp. PI. VII, fig. ". '></ and 7.

Valves thirteen, partly calcified, covered by chitinous membrane. Tergum strongly recurved.
rina with the umbo al some distance from the apex and the part beneath tin- umbo ver)
ily bent. Calcified part of the upper latus of an irregular triangular shape with the base of
the triangle hollowed out. Calcified part of the infra-median latus wine-glass shaped. Carinal

latus with the umbo at the base. Rostrum absent.

This species is represented in the collection of the "Siboga" by three specimens of
differenl si/e. the largesl of which has been figured. It is very nearly related to Sc. chitinosum,
and to Sc. japonicuw, mihi, the latter collected by the "Challenger". To the same group of
species belongs Sc. inflatum. I describe them as so many different species though admitting
the possibility that two or even more of them may afterwards turn out to represent different
forms or varieties of the same species

The capilulum of the present form has the occludent side more strongly arched than
the carinal. It is rather broad, being only one and a half times as long as broad. In conse-
(|uence of the roof of the carina being of considerable breadth near the base, the capitulum is
thick in the undermost part by no means so flat as that of Sc. chitinosum.

The scutum much resembles the same valve of Sc. chitinosum. The tergal segment
of the present species, however. is much shorter than in the other. The apex ol the scutum
is slightly produced and forms a very delicate but distinct beak which reaches to the base ol
the tergum.

The tergum has the calcified part V-shaped. lts occludenl margin is very stronglj
arched; the carinal margin of the calcified part is distinctly hollowed out; where the two margins
join the strongly recurved apex is formed. The surface occupied by the tergum in this species
is smaller than the corresponding surface in Sc. chitinosum.

The carina has the umbo at some distance from the apex: the relatioii ol the length

the part above the umbo to the whole carina being about 1 to -. 1 he part underneath

the umbo is only feebly bowed and has a roof and narrow sides. The roof grows rather broad

towards the base and is nearly quite flat: the ridges so distinct in many other species being

but very feebly indicated. The calcified parts ol the sides are narrow.

upper latus would probablj have a pentagonal shape if totall) calcified. The

79

calcified part has a somewhat irregular triangular form, the base (the margin directed towards
the carinal latus) being hollowed out, the two others margins being convex. The apex is bluntly
pointed, the sharply pointed umbo hing at some distance from the apex.

The rostral latus is trapeziform : the scutal and basal margins are parallel to each
other, the latter being much shorter than the former.

The shape of the calcified portion of the infra-median latus is that of a vvine-cdass
with a very short foot. The umbo is near the base.

The carinal latus is quadrangular and has the umbo at the base of the carinal
margin, where it slightly projects beyond the line of the carina. The carinal margin is hollowed
out and forms with the upper margin a very sharp angle. The lateral margin is indistinctly
hollowed out, the basal margin forms a sharp angle with the carinal margin.

The peduncle is cylindrical, slightly narrower at its base than at the upper extremity.
The scales on the surface are rather broad and placed at considerable distances from one another.
One row is exactly at the carinal side (fig. 6a), then there are three lateral rows on each side
of the peduncle, the rostral side being occupied by two rows, the scales of which alternate
vertically with one another. There are no more than five or six scales "in each vertical row.

Size. The largest specimen collectecl by H.M. S. "Siboga" has a total length of 35 mm.
the length of the capitulum being 22 mm.

1 have not studied the structure of the animal within the capitulum. I found the dwarf-
males lodged in a pouch, formed by a duplicature of the mantle or sac at the margin of the
scutum. Each side has a pouch and in the specimen I have investigated each pouch contained
two males. I believe I observed them also in the other specimens; but as I did not wish to
destroy them I did not investigate very closely with regard to this point. The shape of the
male (PI. VII, fig. 7) is oval ; it is rather large, the longest diameter being not quite 1 mm.,
the breadth about half the length. lts surface is beset with short spine-like hairs; these are
more numerous and especially longer at the peduncular than at the capitular pole of the little
creature. A small opening at the capitular pole gives entrance to the interior of the sac. There
is no tracé of real calcareous plates which would represent the valves of the male; but as
the surface of the sac is naked and smooth in the immediate neighbourhood of the opening,
these slightly swollen marginal parts may after all stand for rudimentary valves. So far as could
be ascertained without cutting sections, the structure of this male corresponds with that of the
male of Sc. regitim, Sc. velutinam and other deep-sea species. Of the internal organs the male
reproductive organs (testicula and receptaculum seminis) are the only ones which are in a
relatively good state of development, the abdominal segments with the long spines attached to
them being visible but in quite a rudimentary condition.

This species was collected at :

Stat. 18. March iS, 1899. Lat. 7°28'.2S., Long. H5°24'.6E. Depth 1018 m. Bottom: fine grey
mud. Three specimens.

11. Scalpellum curiosum n. sp. PI. VII, Fig. 8, Sa and Só.

Valves fourteen, imperfectly calcified, covered by a thin chitinous membrane. Calcified

79

,tmn with a lateral lob( the tergal margin, rergum V-shaped Carina

simpl] 1 with tli<- umbo al a shorl distance from the apex. Upper latus irregularly penta-

i-median latus irregularly wil shaped. Rostrum small triangular.

is represented by ;i single specimen only.

rhe capitulum has an elongate oval shape, sloping gradually into the peduncle. rhe

hitinous interspaces, their colour is not white but yellowish; they are

bj a thin chitinous membrane. The occludent margins of scutum and tergum form

intinuous arch; the apex ol the capitulum is distinctly recurved.

tlv calcified -.ent u m consists of an elongate occludent segment, which is

st at the base and a narrow tergal segment.

Tl.. u m consists óf two segments of about the same width, the carinal segment

much longer than the occludent segment. Apex point distinctly recurvi

irina simply bowed, for of its length with a flat roof bordered on each side bj

a ridge. rhe remaining ' '«■*■ is between the umbo and the apex of the valve and is not flat

but bowed laterally.

Upper 1 a t u s * irregularly pentagonal with the tergal margin longest and the umbo

pointing in the direction of the tergal segment of the scutum.

( >f the valves of the lower whorl, the triangular rostrum (fig. 8«) is by far the

smallest, the carinal latus the largest. The latter valve has the umbo at the outer angle

ath the carina. The infra-median latus is relatively large; it is wine-glass-shaped, the

umbo being placed below the middle and the main growth being upwards. Rostral latera

nearly twice as long as broad, umbo placed at the corner where scutum, rostrum and rostral

latus are nearest to one another. The exact shape of the valves may for the rest be judged

from the drawing (PI. VII, fig. s/".

Peduncle with the upper end widest, slightly narrower at the base, flattened, more

than half as long as the capitulum. Scales large, placed transversely, not numerous, forming

ther about 7 longitudinal rows. The scales are much nearer to one another in the upper

end than downwards.

Si /e. The total length of the specimen was 13,7 mm., that of the capitulum alone 8,7 mm.

only specimen was loose to judge from the objects taken along with it I imagine

that it has been attached to a shell or piece of stone.

Complemental male not observed.

The specimen was collected at :

Stat. 45. April 6, 1899. Lat. 7 24 S., Long. ti8 1 5 .2 E. Depth 794 m. Bottom: fine
mud, with som<- Radiolariae and Diatomeae.

Observation. At th<- same Station 3 other species of Scalpellum wen- collected, viz.

polymorphum, Sc. chitinosum and Sc. crinitum.

12. Scalpellum polymorphum. PI. VII, fig. 9 — 11.

Valves fourteen, covered by membrane, imperfectlj calcified in some of the specimens.
Carina simply bowed, root' bordered on each side by a stronglj developed ridge; umbo ver)

80

Si

near the upper extremity of the valve. Rostrum narrow, partly covered by the lateral parts of
the rostral latera. Infra-median latus elongate, rhombiform, with the umbo near the base. Carinal
latus quadrilateral with the umbo quite at the base projecting beyond the line of the carina.

A perfectly calcified specimen (PI. VII, fig. 9) of this form (form A) was collected at
Station 256, another (form C) very imperfectly calcified (fig. 1 1) at Station 45. I would not have
considered these two forms as belonging to the same species, but for the occurrence of a third
form (form B: fig. 10) - - collected also at Station 45 — to a certain extent intermediate between
the two. A fourth specimen from the same Station 45 is exactly like that of fig. 11. It exhibits,
however, what the specimen I have figured does not, the margins of the valves, and shows
that these have exactly the shape of the corresponding valves in the other specimens I have
at my disposal.

The c a p i t u 1 u m is broad, oval, with the carinal side more strongly bowed than the
occludent side. The apex is not very strongly recurved. The valves of the lower whorl increase
in height from the rostral to the carinal side of the capitulum.

The scutum is perfectly calcified in all the specimens. It varies slightly in shape, as
is shown by the figures 9 — 11 of PI. VII, being at the tergal extremity narrower in the one
specimen than in the other. The occludent margin is more or less strongly convex, the lateral
margin hollowed out near the upper extremity. The basal and lateral margins describe together
one continuous bow. The tergal and occludent margins meet at the apex and form a small
pointed projection which overlaps the tergum.

The tergr urn is trianeular. It has a convex occludent margin, whereas its carinal margin
is slightly hollowed out in the upper and slightly convex in the lower half of its length. The
scutal margin is nearly straight in the specimen with perfectly calcified valves; it is distinctly
concave in the intermediate form (fig. 10) and hollowed out over three quarters of its length
in the specimens with imperfectly calcified valves.

The carina is rather strongly bowed; its roof is deeply notched longitudinally. Its sides
are broadest in the specimen with perfectly calcified valves and much narrower in the other
specimens. A broad stripe of chitinous membrane fills the interspace between the carina and
the other valves in these specimens. Another difference is that the umbo in the specimen from
Station 256 is quite at the apex, and at a little distance from the apex in the specimens with
less perfectly calcified valves.

The upper latus is pentagonal with the umbo at the apex. Beyond the umbo the
apex is slightly more produced in the specimens with imperfectly calcified valves than in the
others. In the latter the two basal margins are straight, in the others these margins are
distinctly excavated.

The rostrum ('fig. ga) is very narrow and on both sides covered by the rostral latera.

The rostral latus is quadrilateral with the rostral margin much shorter than the lateral.

The infra-median latus is rather large, broad and flat at the upper extremity,
much narrower at the base. The umbo is seated near the base at the tip of a triangular
projection, which is slightly raised over the narrow base of the valve.

The carinal latus has a quadrangular shape when perfectly calcified, with the carinal

Si

SIF.OGA-EXPEDIT1E XXXI <l. l '

and basal margins meeting at the umbo and forming a sharp angle projecting beyond the line

of the carina The lateral and upper margins are of aboul the same length and meel at .1 verj

ingle In the specimens with imperfectly calcified valves, the calcified part Ikis the form

nese boot, the part that is nol calcified having the shape of .1 rectangular triangle.

The peduncle is cylindrical and shows 8 to 12 longitudinal rows of scales. In the

imens with perfectly calcified valves these scales are perhaps distributed slightly more

ilarly than in the oth<

[*he specimens figured measure 20, 19 and 20,0 mm.; their capitulums 13,;,, 13,8
and 10.2 mm.

The stiulv of the structure of the animal contained within the capitulum has yielded the
following results

Mc ut li triangular when seen from above, slightly bullate. Lab rum with hardly
distinguishable teeth; pal pi conical, rather pointed at the extremity, with short and nol
numerous hairs, those on the apex little longer

Mandibles with three teeth, which are pointed at the extremity and slightly swollen
a little before the extremity; the inferior angle is blunt and furnished at the under side near
the extremity with about tour triangular, small, sharp teeth. Teeth 2 and 3, and 3 and inferior
angle at shorter distances trom one another than teeth 1 and 2. Near the inferior angle the
surface bears a few very delicate hairs placed in groups of three or tour. Along the under
margin are planted short hairs.

Maxillae rather narrow; edge with a very distinct notch, a little above the middle;

three strong spines, of which the tirst is the strongest, above the notch; one spine in the notch

and 7 to S rather strong spines, which do not differ much from one another in strength, beneath

the notch. 'The surface of the maxilla bears delicate hairs, partly in groups, on the distal

tremity only. Apodeme broad, not very long.

Second maxillae of the ordinary shape, with hairs along the outer and inner side
and also at the apex; a long tubular process, which is flat and truncated at the extremity, gives
entrance to the body cavity.

rri. First pair at some distance from the second pair: rami unequal: the anterior
shorter and broader, the posterior longer and narrower. Both rami have a long basal segment,
which is indistinctly divided into smaller segments; the short ramus has moreover 4, the long
ramus 8 distinct segments. Along the sides of the more or less flattened segments stout spines are
planted on knobs; more slender spines or hairs are scattered all over the surface of the segments.
md c ir rus with about 20 segments in each ramus: the tirst segment is long and
consists of several segments fused together; the following segments short, quadrangular, gradually
growing longer, the last being as long as the foregoing op.es but considerably narrower. Spines
on the anterior side stouter and planted on knobs: four pairs on each segment as a rule; those
on the posterior side more delicate, less numerous and not placed so regularly.

Sixth cirrus having in each ramus a long basal segment consisting of several segments

sjether and about 25 clearly distinguishable segments. I hese grow gradually longer and

from the base to the extremity. Each segment bears, as a rule, 4 pairs of long spines

82

33

on the front side and one or two very short spines on the posterior margin near the extremity.
The latter margin in some of the segments bears a spine at about the middle of its length ;
this margin, moreover, is delicately hirsnte with extremely short hairs or teeth.

Caudal appendages long, consisting of 8 narrow segments. Each segment bears one
longer hair near the extremity; those on the six last segments are very long, very stout and
distinctly serrated. On the interior margin each segment has one or two much more delicate hairs.
The last segment bearr a group of three very long, feathered hairs or spines at the extremity.

No p e n i s.

Male. I found only one male on the specimen I investigated more closely in this regard :
it was the specimen with partly calcified valves represented on PI. VII in Fig. 11. I found it on
the inner side of the left scutum, near the occludent margin. It was not in a very good state
of conservation, the body with the cirri hanging out of the opening of the sac. The longest
diameter of the sac was about 1,2 mm., the breadth slightly over 0,5 mm. The sac or mantle
itself was very thin and soft, not resistant, tough. About the middle of the longest diameter
little prehensile antennae are attached. The surface shows numerous very short hairs, arranged
in transverse rows, placed at short distances from one another.

This species was taken at the following places :

Stat. 45. April 6, 1899. Lat. 70 24 S., Long. ii8°is'.2E. Depth 794 m. Bottom : fine grey
mud. One almost perfectly, two imperfectly calcified specimens.

Stat. 256. December 11, 1899. Lat. 5°2Ó'.6S., Long. I32°32'.5E. Depth 397 m. Bottom:
greyish green mud. One perfectly calcified specimen.

Affinities. This very interesting species is perhaps more closely allied to Sc. rutilum
Darwin than the descriptions of the two species would at present lead us to suppose. It is also
similar in several regards to Sc. distiuctum Hoek.

13. Scalpellum distiuctum Hoek. PI. VII, hg. 12.

HOEK, Cirripedia collected by H. M. S. "Challenger". 1883. p. [II, pi. VI, fig. 10 & 11.

H. M. S. "Siboga" collected a Scalpellum at three different Stations which I think is
identical with the above-named species. The very curious forms of the scutum, the upper latus
and the infra-median latus leave no doubt on the matter.

Yet the resemblance is not absolute and I have therefore thought it useful to give a
figure of one of the "Siboga" specimens. The original description was given from a single
specimen, a circumstance which of course makes that description less reliable.

The smallest of the two specimens collected by the "Siboga" (total length 20 mm., length
of the capitulum 14,4 mm.) has been figured. (The capitulum of the "Challenger" specimen
had a length of 15,5 mm. and that of the largest "Siboga" specimen 19 mm.). Comparing the
figure with that given in my "Challenger" Report (PI. VI, fig. 10) one is struck with the much
more prominent lines of growth and ridges on the valves of the "Challenger" specimen. To
some extent this is the fault of the lithograph: on the original pencil-drawing these lines are
much more delicate-, on the upper part of the infra-median latus they are however stronger
developed in the "Challenger" than in one of the "Siboga" specimens.

83

e witli the rid il"- roof of the carina: these ridges are

distinct in the pecimens .ts in thal of the "Challenger". I sh<

mention also that the scales . • i" t li« - peduncle which in the ■Challenger" specirnen are pla«
jn i-i i .t ..ul.ir rows, in the largesi "Siboga" specimen may be said to form longitudinal

., in the smaller specimen, however, this can hardly 1"- said.

Wuii regard to the shape of the carina I found that this species belongs also to the
ie umbo of the carina is not quite at the apex of the valve, but at a short distance
from it. In this regard it much resembles Sc. polymorphum with which it corresponds also in
ral other regards.

Finally 1 must point < uit. that the chitinous interspaces b( tween the valves which wi
rather broad in the ■Challenger" specimen, are much more prominent in the larger "Sibi
specimen (from Station 175 than in the smaller the one figured which was taken at Station

Th. structure of the animal of the only specimen taken 1>\ the ■Challenger" was not
studied; 1 have thought it useful, therefore, to examine one of the ■Siboga" specimens.

Mouth not very bullate; «rest of the labrum with a row of very small knobs at the
of the teeth; pal pi conical, rather small, with a group of short bristles at the tip and
a couple of very short spines on the internal margin about the middle of its length.

Mandibles with three teeth; distance between 1 and 2 slightly greater than that
between 2 and 3; inferior angle close to tooth 3, short, rounded and delicately pectinated.
Short hairs are planted along the under margin.

Maxillae with a not very distinct notch aboul or a little above the middle of the edge;
above the notch three unequal spines, in the notch (or as fourth spine above the notch) one
spine; beneath the notch six spines. Apodeme stout, rather long and broader at the extremity.
Outer maxillae rounded, with the bristles divided into two separate tufts; the orifice
giving entrance to the bod) cavity at the end of a long and Hat process, transversely cut off
at the extremity.

Cirri. First pair short, not separated from the second by an interspace; rami unequal
in thickness and slightly in length: the shorter ramus has about S broad, the longer 10 more
cylindrical segments. The lust segment in both rami is much longer than the others, the last
one considerably shorter. In both rami the segments are thickly clothed with spines.

>nd cirrus (in the specimen investigated both rami broken ofl at one side. and one

ramus broken off at the other side. The only remaining ramus has [7 segments, the first of which

is rather long, the following nearly quadrilateral, the last ones cylindrical and much narrower.

Sixth cirrus has 22 segments in both rami: the first one verj long. then come four

or five nearly quadrangular segments, the following nine growing longer and narrower, the

beinc the longest o,' all and nearly five times as long as broad. The last sesrments qtow

still narrower but diminish in length: the last is very narrow and tapers towards the extremity,

where three short spines an- planted. The number of pairs of s|iines found on the front side

inent is from three to seven; this number is largesl at the I4,h segment.

indal appendages long and narrow. tapering towards the extremity and consisting

or o (right side segments, of which the penultimate is the longest. Near the

84

§5

end of most segments are planted a few delicate hairs, one of those found at the tip of the
last segment being much stouter and more than twice as long as the last segment. This hair
is very distinctly barbed or feathered.

No penis.

Dwarf mal es. I found three on the left and two on the right side of one of the
specimens. They are lodged in a pouch formed by the mantle along the inner side of the scutum,
near the occludent margin, slightly in front of the adductor scutorum muscle. They have the
ordinary shape and structure; their size is 0,8 X 0,5 mm. The antennae are situated at about
]/3rd the length of the animal from the posterior extremity, the anterior extremity or pole being
considered to be where the large opening which gives entrance to the sac is found. No tracé
of calcareous plates or rudimentary valves. Surface covered with very small hairs or spines,
arranged on transverse rows all over the surface. The transverse rows are very close to one
another and numerous. A few slightly longer hairs are planted on both sides of the longer axis
of the oval opening of the sac. Of the interior structure are seen the rather large testicula,
the pointed extremities of which are directed towards the posterior pole of the body; then the
receptaculum seminis densely filled with threadlike spermatozoids; cement-glands at the base of
the antennae; a rudimentary thorax and abdomen bearing long spinedike hairs at the extremity.
The latter represent the cirri and are directed towards the opening of the sac.

The "Challenger" took a specimen of this species in the neighbourhood of the New
Britannia Archipelago, east of New Guinea ; H. M. S. "Siboga" collected specimens at the
following places :

Stat. 88. June 20, 1899. Lat. o° 34.6 N., Long. U9°8'.5E. Depth 1301 m. Bottom: fine,

grey mud. One specimen.
Stat. 175. Aug. 30, 1899. Lat. 2°^y'.'/S., Long. I30°33'.4E. Depth 1914 m. Bottom: fine,

grey and green mud. One specimen, attached to the shell of a Gastropod.
Stat. 208. Sept. 22, 1S99. Lat. 5°39'S., Long. I2i°23'.5 E. Depth 2218 m. Bottom: grey mud.

One specimen, a small one, attached to a chitinous tube, the skin of the siphon

of a Lamellibranchiate Mollusc most probably.

Observa t i o n s. This species is nearly related to the foregoing : Sc. polymorphum.
The form of the scutum and of several other valves, however, show its clistinctness.

D. Sectio: Arco-Scalpellum

14. Scalpclluni moluccanum Hoek. PI. VII, fig. 13.

Hoek, Cirripedia collected by H. M.S. "Challenger". 1883, p. 104; pi. V, figs. 3, 4.

H. M. S. "Siboga" collected one specimen of a Scalpellum species which I think must
be referred to this species. To the left side of this specimen two rather large specimens of the
species which I have proposed to call Sc. inflatum (p. 76) were found attached and in consequence
of this the specimen is slightly abnormal in shape. The carina especially has grown quite
asymmetrical making it difficult to judge its original shape.

The specimen belongs certainly to the group of species : Sc. regm/u, Sc. Darwini and
Sc. moluccanum which are nearly related to one another. It comes nearest to Sc. moluccanum
and as it was taken at about the same locality (see below), I may be entitled to consider it

35

.i-, beloi rhe description of the "Challenger" specimen was given from a

iniiii

■ I this specimen are to a largi red by chitinous membrane,

in the specimen of Sc. moluccanum, described in the "Challenger" report)

of the valves uncovered. This membrane was moreover wanting on the left sidi

capitulum, at the places from which I had removed the other Scalpellums. Continuing to

takt- awa\ this chitinous membrane I discovered that the area of each valve was distinctly

limited by lim • and tliai the calcareous valve only occupied a part of that area: only

after this chitinous covering was removed was it possible to make out the exact shape ol each

lecide whether Sc. regium and Sc. moluccanum are really different species, and also

t" which the present specimen belongs, it would by all means be necessary to deal with the type

is 1 have now done with the "Siboga" Scalpellwn. Fig. i .; of PI. \'1I represente that

men, seen from the left side alter the chitinous covering was removed from the capitulum.

Whereas the "Challenger" took the species at Lat. 4 2 1 ' S. and at Long. 129 7 ' 1-..

■tli of 1425 fathoms (about -505 m.), Il.M.S. "Siboga" collected it at:

St.it. 271. December 21, [899. Lat. 5 46 S., Long. i34°o'E. Depth [788 m. Bottom: bluish
green mud of a uniform appearance.

15. Scalpellwn hamulus n. sp. PI. VII, fig. 14 and \j\a.

Surface of the capitulum and of the peduncle covered by a thin membrane with very
short hairs. Valves fourteen. Carina simply and strongly bowed with a nearly flat roof which
is very wide at the base. Upper latus very narrow at the base. Rostrum triangular. Valves of
the lower whorl small with exception of the rather well developed carinal latus. l'mbo of the
latter at the upper extremity.

This beautiful species is represented by one specimen only.

The capitulum is rather robust, thick especially in the under part: it is of an elongate
oval shape with the apex slightly produced. The valves of the lower whorl are relatively small,
the carinal latus excepted. I he valves touch each other and are covered by a membrane which
is clothed with short hairs.

The scutum is very broad al the base, the lateral margin not béginning above the
apex of the infra-median latus (as is the rule in this genus) luit above the middle of the upper
margin of the carinal latus. Apex produced; tergal margin slightly hollowed out; occludent
margin convex. Not quite twice as long as broad.

The tergum is likewise rather broad. It has the scutal margin convex and the occludent
margin also convex. The apex is slightly produced and terminates in a short luit rather sharp
and feebly recurved point.

The carina is simply bowed with a nearly flat roof widening very considerably from
the a ■ the base. The root" is slightly convex laterally and its borders insensibly pass over

into the rather narrow side parts.

The upper latus is of a triangular shape with the umbo at the apex fitting into the
irmed by the lateral margin of the scutum and the scutal margin of the tergum. The

86

8?

carinal margin describes a curve, that part which represents the basal margin of the same valve
in other species being very short.

The rostrum (fig. 14^) is small, triangular, with the base directed towards the peduncle.
lts apex separates the two umbones of the rostral latera from one another; though small the
rostrum is distinctly visible at the surface.

The rostral latus is extremely low, its scutal and basal margins running nearly
parallel to each other.

The infra-median latus is also small. It has a triangular shape with the umbo
at the apex.

The carinal latus has a convex carinal and a hollowed out upper margin ; where
they meet the umbo is seated; that part projects outwards and forwards.

The peduncle is robust, cylindrical and rather long, being about 3/3lds as long as the
capitulum. It is covered by prominent scales placed in five longitudinal rows.

Size. The length of the animal is 30 mm., that of the capitulum 19 mm.

The specimen representing this species was collected by the "Siboga" at:

Stat. 256. December il, 1899. Lat. 5°26'.6S., Long. I32°32'.5 E. Depth 397 m. Bottom :
greyish green mud.

Observation. This species is no doubt nearly related to the Atlantic species Sc.
velutinum Hoek. Yet it can be easily distinguished from that species by the form of the
upper latus, by the rostrum and by the shape of the carinal latus. It belongs to
the same group of species as Sc. diota n. sp. but the rostrum and the infra-median
latus of the latter species are so different that there can be no question, I think, of these
two forms being distinct'.

'b

16. Scalpellum diota n. sp. PI. VII, fig. 15 and 15 a.

Valves 14, covered with hairy membrane. Carina simply bowed, large. Valves of the
lower whorl small, increasing in height from the rostral to the carinal side of the capitulum.
Carinal latus with the umbo at the strongly recurved apex.

This species is represented by one specimen only.

Capitulum with the occludent margin nearly straight and the carinal margin very
strongly convex, with the upper valves large and those of the lower whorl small. The colour
of the specimen (in spirits) is light pink, large red spots being observed along the margins of
the larcfer valves etc.

S cu turn quadrilateral, not quite twice as long as broad. Occludent margin nearly
straight, lateral margin convex, apex produced, pointed, slightly overlapping the tergum.

Tero-um lar^e, triangular. Occludent margin nearly straight; apex pointed, slightly
produced, hardly curved towards the carina.

Carina simply bowed, roof flat, a depression being only visible at the base between
the two carinal latera. The roof increases in width very considerably from the apex to the
base. Sides fiat, rather narrow.

87

Upper l.iiu^ triangular with the umbo at the apex, this pari acuminated fitting into
the angle between the scutum and the tergum. Lateral margin com irino-lateral margin

sirm ivex and divided into two unequal parts bj the recurved apex ol the carinal latus.

Rostrum (fig. i£ imall, elongate, not triangular, laterally covered by the rostral latera.

Rostral latus quadrangular, low, with the lateral margin only slightly longer than
the rostral margin.

Infra-median latus small, narrow, slightly increasing from the recurved apex to
the base ' mbo at the ai

i arinal latus with the umbo at the strongl) recurved apex. The carinal margin is
convex, the upper lateral margin hollowed «uit.

Peduncle short, flat cylindrical, only ' "' of the length "f the capitulum. S al< rather
ed in five longitudinal rows.

Size. The total length of the specimen is i<> mm., that of the capitulum about 7,5 mm.

The specimen representing this species in the collection of the "Siboga" was taken at:

Stat. 251. December 8, 1899. Lat. 5 28'.4 S., Long. i32°o'.2K. Depth 204 m. Bottom: hard
il sand.

Observati ons. This species is nearly related to Sc. hamiilns as also to Sc. rubrum
Hoek which was taken by the " Challenger" near Lu/on, at a depth of 180 to 207 m. There
are however small differences in the shape ol the valves, ol the rostrum especially, as also in
the size and number of the scales of the peduncle. The description of Sc. rubrum was also
given from a single specimen; its capitulum measured only 5 mm.

17. Scalpellum sessile n. sp. PI. VII, fig. [6.

Valves thirteen, not covered by membrane. Carina short, simply bowed with the umbo
at the apex, no flat roof, but laterally bowed. Upper latus trapeziform. Valves of the lower
whorl large. Infra-median latus triangular, with the umbo at the apex and a rather broad basis.
Carinal latus very large, pentagonal, with the umbo at the upper extremity.

This species is represented by four specimens, one being very small.

The capitulum is rather thick, with the carinal margin much more bowed than the
occludent margin. No membra /ers the valves. Whereas the valves of tin- lower whorl are

the scutum, tergum and carina are relatively small, the upper latus medium-sized. The
valves nearly touch each other; they cannot be said to be separated by chitinous interspaces.
The length of the capitulum is twice the breadth it has in the middle, a little above the base
of the carina.

The scutum is about twice as long as broad. The occludent margin is hollowed oul
in the lower and convex in the upper part: the apex is produced, the tergal margin much longer
than the basal margin. The lateral margin is more than half the length of the occludent margin.

The tergum is triangular; its three margins, the carinal being the longest, are convex.

The carina is short, simply and rather strongly bowed, with the umbo at the apex.
• and sides are not separated by ridges, the dorsal surface of the valve being laterall) bowed.

88

§9

The upper Iatus is trapeziform. There is a short but distinct carinal margin, the
leneth of which is about one fourth that of the scutal margin. The scutal and basal margins

O ©o

meet together at a rather sharp angle.

The rostral latus quadrangular. Basal and scutal margins nearly parallel to each
other, the second twice as long as the first. Rostral margin nearly straight and only a trifle
shorter than the slightly convex lateral margin.

The i n f r a - m e d i a n latus is triangular, with a well-developed basal margin and the
umbo at the apex. lts rostral margin is slightly hollowed out, its carinal margin slightly convex.

The carinal latus is very large and has an irregular pentagonal shape. lts carinal
margin is divided into two : a large part meeting that of the same valve of the other side
along the whole length and a very short part separating the valve from the carina. The latter
margin forms an angle with the upper margin and here the umbo of the valve is situated.
Upper and lateral margins of about the same length ; basal margin very short.

The peduncle is short and has a conical shape. The surface is covered with rather
large scales, which are chitinous but not very prominent. They are placed in seven not very
distinct longitudinal rows.

Si ze. The specimen figured PI. VII, fig. 16 has a total length of 5,2 mm., the length
of the capitulum being 4 mm. They were found attached to a small stem of what I take to
be a calcareous coralline.

The study of the structure of the animal within the capitulum has yielded the fol-
lowing results :

Mout h seen from above triangular, with the part directed forward rounded and bullate.
Labrum with a row of small but distinct teeth ; p a 1 p i conical with a tuft of spines at the
tip and a row of half a dozen shorter spines or hairs along the outer margin.

M a n d i b 1 e s with three teeth ; the distance between the extremities of tooth 1 and 2
twice as great as that between tooth 2 and 3. Inferior angle pectinated and at a very short
distance from tooth 3. The upper margin of tooth 3 shows traces of being pectinated -
showing agreement with Sc. balanoides Hoek also in this regard.

Maxillae with the outer edge deeply notched about the middle; above the notch 4
spines, two of which are longer; beneath the notch the edge bears 5 or 6 spines and is
slightly protuberant.

Second maxillae not larger than usual and of the ordinary shape ; spines in three
oroups, with some distance between two-, openings giving entrance to the body-cavity at the
tip of a swelling — not at the end of a tubular process.

Cirri. First pair close to the mouth and at some distance from the second pair.
Rami unequal : shorter ramus slightly broader, composed of 5 or 6 segments ; longer ramus
more elongated, having 7 segments. In both rami the limits of the segments are indistinct ;
they bear numerous hairs, partly at the surface, partly along the margins.

Second cirrus also has unequal rami; the segments of both rami are cylindrical but
the longer one has eleven, the shorter only nine segments.

Sixth cirrus (like the 3"1 — 5th) not very elongated with nearly equal rami of 16

89

SIBOGA-EXPEDITIE XXXI a. 12

rments. 3 I segments have only two pairs of spines ai the anterior margin one pair

ven long near the extremity and .1 second shorter pair about the middle ol its length.

iudal appendages verj minute, one-jointed with a few spines near the extremity
and a short and feeble claw-like spine at the tip.
No penis.

l'li, formed a single cluster in the specimen I opened; the) had a much more

ngated shape than in several other species of Scalpellum. They measured 0,47 X 0,27 mm.,
their number being 1 7.

This specimen was furnished with .1 dwarf male at one side only. The latter was attached
t<> the inner surface ol the scutum near the occludent margin. Its shape was pear-like, the
luncular pole being considerably the narrower. It showed no tracé of valves. The prehensile
antennae were inserted very near the peduncular extremity. lts si/c was 0,5X0,3 mm.
The "Siboga" collected this interesting little species at:

St.it. 241. December i, [899. Lat. 4 24.3 S., Long. [29 |-9'.3 E. Depth 1570111. Bottom: dark
-~.m<l with smal! stones.

Observation. This species is very nearly related to Sc. balanoides Hoek collected
during the cruis.- of the " Challenger" at Lat. 5 42'S., and Long. [32°25'E. at a depth of
[29 fathoms, about 230 m. The latter species lias about the same size and lives attached to
the arms of Metacrinus Murrayi. Sc. sessile differs from it, 1" by the trapezoid nol triangular
m ut' its upper latus; 20 by the greater breadth of its infra-median latus; V by the form of
its carinal latus, which in Sc. balanoides has the apex, where the umbo is, produced and even
slightly recurved; and 4" by the shape of the carina, which is much more strongly bowed in
Sc. sessile than it is in Sc. balanoides. Perhaps on closer examination of the "Challenger" form at
least some of these differences might turn out to be not so important as 1 must consider them now.

[8. Scalpellum ciliatum n. sp. PI. VII, fig. 17.

Valves fourteen, covered by membrane, clothed with very long hairs. Carina simply bowed,
no flat roof. Tergum very large. Valves of the lower whorl small. Upper latus indistinctly

quadrangular. Rostrum small, triangular.

This very small species is represented by a single specimen only.

The capitulum elongated, with the apices of the tergum and scutum produced. The
hairs which clothe the membrane are longest along the carinal margin of the capitulum.

The scutum is elongated. quadrilateral, more than twice as long as broad, with the
upper part produced and pointed.

The tergum is large, elongated rhomboid; the umbo is at the apex which is bluntly
pointed and not produci

The uppermost (umbonic paris of scutum and tergum are naked, not covered by membrane.

The carina is simply bowed longitudinally and also laterally. It reaches to about half
the length of the carinal margin of the tergum.

The upper latus has the scutal margin parallel to the occludent margin ol the scutum
and it-- is not produced. The carinal and basal margins form together an arch.

90

9i

The rostrum is very small, triangular, with the base of the triangle directed towards
the scuta.

The rostral latus is quadrangular with the longer scutal and shorter basal margins parallel.

The infra-median latus is triangular ; umbo at the upper extremity.

The carinal latus has a pentagonal shape with the umbo at the upper extremity,
at the angle formed by the carinal and upper lateral margin.

The pe du nel e is cylindrical and relatively short; the scales are placed in transverse
rows and are large and of an irregular shape ; they seem to be broken off from the lower
part of the peduncle.

Size. Length of the capitulum 3,4 mm., of the whole animal 4,7 mm.

This species was taken at:

Stat. 227. November 13, 1899. Lat. 4°5o'.S S., Long. I27°59'E. Depth 2081 m. Bottom: grey
mud with an upper layer of brovvn, both mixed with sand. One specimen.

Observation. This species is, most probably, nearly related to Sc. hirsutum Hoek
collected by the "Challenger" at a depth of 1500 m. between Celebes and Halmaheira. There
are, however, several more or less important differences between the two forms, which I think
make it preferable to consider them as distinct; e. g. in the shape of the scutum, tergum and
upper latus, but especially in that of the carina and the rostrum. As Sc. hirsutum has a capitulum
of 6 mm. and Sc. ciliatum of 3,4 mm. only, the latter may be found to represent a not quite
full-grown stage of the first — a somewhat richer material, however, is necessary to make this out.

19. Scalpellum pellicatum n. sp. PI. VII, fig. 18, \%a and 19.

Valves fourteen, covered by membrane of a velveteen appearance. Carina simply bowed,
roof nearly flat not bordered by ridges ; apex projecting freely. Upper latus quadrangular.
Rostrum triangular. Infra-median latus triangular. Carinal latus with the umbo projecting beyond
the line of the carina.

This species is represented by one large, one fairly large and half a dozen small specimens.
The largest specimen is figured.

The c a p i t u 1 u m is white, covered by a membrane which bears short hairs standing
off from the surface and thus giving it a velveteen appearance. Most of the valves are separated
from one another by chitinous interspaces. The capitulum is broadest at its base, its length is
less than one and a half times the breadth.

The scutum is quadrangular; the occludent margin is slightly convex, the basal and
lateral margins are nearly straight, the tergal margin slightly hollowed out and forming with
the occludent margin a slightly recurved apex.

The tergum has the carinal margin divided into two parts : a larger lower part which
is convex and a shorter upper part which is straight. This upper part of the carinal margin
runs parallel to the scutal margin : hence the whole valve has the shape of a parallelogram.

The carina is simply and strongly bowed and has the umbo at the apex which projects
freely beyond the carinal margin of the tergum. The roof of the carina is broad at the base,

91

the sides are best developed in the under pari of the valve; the angle the rooi forms with
the side i- than 9

The upper latus is quadrangular and rather large. The angle formed by the scutal
and basal margins is truncated. rhe umbo is near the angle the scutal margin forms with the
il. rhe carinal margin is the shortest.

The rostrum is triangular with the apex directed to the base of the scuta. There is
.1 narrow but distinct chitinous interspace between the rostrum and the rostral margins ol the
rostral lat<

The rostral latus is broad but very low; the scutal margin runs parallel to the
' margin, the short lateral and rostral margins are both con\

The infra-median latus is triangular, the umbo is at the apex which is distinctly
curved towards the rostral side of the capitulum: the rostral margin is hollowed out, the carinal
margin distinctly conv<

The carinal latus is pentagonal, the carinal margin being divided into two part
The upper part is hollowed out, the lower convex. Where they meet the umbo is seated: a
pointed and slightly recurved triangular part projects beyond the line of the carina. The basal,
lateral and upper margins of the carinal latus are of about the same length.

The peduncle is cylindrical, bent towards the rostral side. It is broadest where it is
attached to the capitulum and is Iaterally compressed and conical in the upper part. It is covered
with a hairv transparent membrane through which the scales are visible. They are placed at
some distance from one another and are arranged in seven or eight longitudinal rows.

Size. The capitulum of the largest specimen had a length of 2; mm. The total length
was about 40 mm.

According to the label tin- larger specimen <>f this species was found attached to a
specimen of Culeolus thysanotus Sluit. This was collected at Station 94. The smaller specimens
are attached to one another, as also to a small black coloured stick or spine, the nature of
which is unknown to me.

The study of the structure of the animal contained within the capitulum has yielded the
following results:

Mouth seen from above triangular, with the apex of the triangle directed towards the
adductor muscle; the prominence on which the mouth is situated is not very elevated in this specii

Lab rum with extremely small teeth along the edge; palpi short, broad at the base,
triangular, with the apex rounded. The inner margin is furnished with numerous hairs growing
slightly longer and more numerous towards the apex.

Mandibles with three teeth and the inferior angle; the latter delicately pectinated ^\\
both sides. but especially so along the interior margin; a slightly broader spine or small tooth
at the tip of the inferior angle. The distance between tooth 1 and 2 about twice as long as
that between 2 and 3, or ; and the inferior angle. Surface of the exterior part with numerous
delicate hairs, placed in groups <>l two or ihree.

Maxillae have the edge without distinct notch, but with a little excrescence bearing
two spines at the tip at about one fifth of the length of the edge from the inferior angle.

92

93

Spines numerous and of nearly equal size, the only exception being the upper spine which is
considerably stronger. Only a small part of the surface, near the exterior edge, is covered with
delicate hairs which are placed in groups of two or three.

Second m a xi 1 1 a e with the inner margin distinctly divided into two rounded parts
each bearing a group of delicate spines. Outer surface curved and also bearing numerous spines;
opening giving entrance to the body-cavity on a small rounded knob.

Cirri. First pair placed at some distance from the second, close to the mouth; rami
short and unequal. The anterior is the shortest and has eight to nine segments, most of them
being much broader than long; posterior ramus has eleven to twelve segments which are nearly
as long as broad, the last being nearly spherical. Surface of all the segments covered with
hairs, the distal segments being more densely clothed than the basal. Several hairs, on the
distal segments of the longer ramus especially, long and irregularly curled.

Second pair longer than the first pair ; shorter, however, and more robust than the
cirri of pair 3 — 6. Longest ramus has 24 segments: the first 10 nearly quadrangular, next come
8 longer segments, which are about twice as long as broad, finally 6 segments which are
narrower, but slightly longer than broad. Shortest ramus having 22 segments, 11 of which are
nearly quadrangular, 5 cylindrical and 6 much narrower and shorter. Spines On the front side :
3 or 4 pairs on the middle segments, 1 or 2 pairs on the distal segments; on the posterior
side: groups of 4 — 6 stouter and a few more delicate spines 011 each segment near the extremity.

Sixth cirrus long, slender, 28 — 29 segments in each ramus. Segments 1 — 8 nearly
quadrangular, 9 — 20. cylindrical, the longest about twice as long as broad; segments 21 — 29
narrower, not much shorter than the middle ones. On the front of each segment are 4 to ^
pairs of spines, on the dorsal side groups of three or four spines, of which one or two are
stronger, near the extremity of each segment.

Caudal appendages (PI. VII, fig. 19) 4-jointed with a long and very broad basal
segment and three minute distal segments; extremely short hairs along the interior margin of
segment 1 , 2 and 3 and at the extremity of 4.

Penis short, about twice as long as the caudal appendages, cylindrical, conical at the
extremity; indistinctly ringed and having short hairs spread over its surface.

Complemental males. I observed on the right side of the hermaphrodite animal
one, and on the left side two small males. They are very small (0,6 X 0,4 mm.), have a short-
oval shape and are lodged in a pouch formed by a duplicature of the mantle, which at that
place is rather thick and little transparent. The sac or mantle which covers the little male has
the surface covered with minute particles of sand or mud, whereas the hairs which ordinarily
occur could not be made out. Near the opening of the sac only some very short spines were
seen which seemed to be inserted on the tip of a couple of small excrescences.

The Stations where this species was collected are :

Stat. 94. June 26, 1899. Lat. 50 \\' .2 N., Long. H9°35'.4E. Depth 450111. (chart). Bottom :

apparently sand and stone.
Stat. 256. December 11, 1899. Lat. 5°26'.6S., Long. i32°32.5E. Depth 397 m. Bottom:

greyish green mud.

93

94

ation. In the smaller specimens the breadth "f the capitulum ;it the bas
about the same .is at the height of the upper latus, In these the carinal margin '>f the tergum
is not si. distinctly divided into two parts, the apex of the carina does not project freely and
the umbo of the carinal latus is nol ^»-.it « -< 1 al the tip "l a triangle which projects beyond the
line of the carina. As 1 feel convinced that these smaller specimens, some <>f which were
hed to the larger, belong i" this species, I am inclined to admit that several of these
diffei result from there being a considerable difference with regard to age and maturity

between the specimens at my disposal.

Remark when correcting the proof of the description given above.

This species is, without doubt, nearly related t" Sc. rociaói/e Annandale' from Bali Straits, depth

fathoms = ,>n> m. The characteristic figure Annandale gives of the group of specimens

of bis new species is perhaps not quite m> useful for recognizing an individual specimen. As

occur differences between bis description of the valves, of the appendages, mouth-

ind mine, I think it better therefore to keep my species separate; future investigators

will, no doubt, easily find out whether the two species are identical or not.

Scalpellum imbricatutn n. sp. PI. YII1, fig. 15 anti 15a.

Valves 1 |. Surface of valves covered by a slightlj villous chitinous membrane. Carina

large, nearly reaching to the apex "f the tergum, simply bowed, roof furrowed longitudinally.

Rostrum narrow, indistinct. Infra-median latus narrow, with the umbo at the apex. Carinal latus

with the umi", at a short distance from the base, slightly projecting beyond the line of the carina.

This species is represented by one specimen only.

The capitulum is rather narrow, the carinal margin regularly bowed, the curvature

ly reaching to the apex of the scutum. The surface is covered by a tliin slightly villous

membrane which makes it difficult at first sight to distinguish the margins of the valves. There

an- slight intcrspaces between the different valves, specially distinct in the corner where the

upper latus, the carinal and infra-median latera meet.

The scutum is quadrilateral ; the length not quite twice the breadth. The apex is
pointed and slightly overlaps the tergum.

The tergum is triangular, its occludenl margin nearly quite straight. The apex i-
bluntly pointed and hardly produced.

The carina is very large, nearly reaching to the tip of the tergum. It lias a very
pronounced curvature. It has well developed sides and a roof that increases in breadth though
not very much from th<- apex downwards. The roof is distinctly furrowed longitudinally.

The upper latus is pentagonal; its umbo is at the apex which fits into the angle
formed by the scutal margin of the tergum and the lateral margin of the scutum.

The rostrum (PI. VIII, fig. 1 5 a) is narrow, slightly increasing in breadth downwards, fitting
:lv between the rostral margins "i the rostral latera, more or less concealed by membrane.

1 ' Malaysian Barnacles in ilic Indian Museum. Memoirs of thi l. I, 5. 1905, p. 77,

94

95

The rost r al latus is quadrilateral, with the lateral margin considerably longer than
the rostral margin.

The i nfra-m e dia n latus is narrow, pointed at the apex where the umbo is.

The carinal latus has the umbo near the base, slightly projecting beyond the line
of the carina. lts carinal margin is distinctly hollowed out.

The peduncle is nearly cylindrical: its length is nearly 7:"!s of the length of the
capitulum. lts surface is covered with small rounded scales, partly covering one another, each
scale being rounded and slightly swollen at the free extremity.

Si ze. Length of the whole animal 12,5 mm., of the capitulum 8,6 mm.

A single specimen of this species was taken by the "Siboga" at:

Stat. 251. December 8, 1899. Lat. 5°28'.4S., Long. i32°o'.2 E. Depth 204 m. Bottom: hard
coral sand.

Observation. The size and the form of the carina, combined with the shape of
the valves of the lower whorl, of the carinal latus especially, will make it easy to distinguish
this species from those nearly allied (e. g. Sc. elongatum Hoek), should it again turn up. It
belongs without doubt to the same group of species which include Sc. pcllicaium mihi and
Sc. sociabile Annandale.

21. Scalpellum crinitum n. sp. PI. VIII, fig. 1 and ia.

Valves fourteen, covered by hairy membrane and separated from one another by broad
chitinous interspaces. Carina simply bowed with the umbo at the apex, roof laterally convex.
Rostrum flat conical. Infra-median latus triangular. Carinal latus with the umbo slightly beneath
the middle of the carinal margin.

The capitulum is elongated, twice as long as broad, rather thick. The limits of the
valves are very indistinct, in consequence of the whole capitulum being covered by a hairy
membrane, to which moreover algae or other organisms are attached. Broad chitinous interspaces
occur, especially between the carina and the other valves and round the upper latus.

The scutum is quadrangular with the occludent margin nearly straight and the umbo
at the slightly produced apex. The valve is rather narrow at the base and grows slightly
broader towards the upper extremity. Ridges of growth distinct on the under part of the valve.

The tergum is triangular. lts occludent margin is convex, its apex rounded and not
produced in the specimen figured, rather sharp, though harclly produced in the other specimens.

The carina is simply bowed and has the umbo at the apex. The roof is laterally
convex and slopes insensibly into the sides. The hairs which are nowhere wanting on the
chitinous membrane that covers the capitulum, are longest along the free margin of the carina
from which they stand off at right angles.

The upper latus is elongated and narrow, especially in the basal part. This at least
holds o-ood for the calcified part of the valve. The scutal margin is hollowed out, its carinal
margin is convex.

The rostrum has about the same height as the rostral extremity of the rostral latus.

95

h is broadi the base. very narrow in the upper part Ii is not covered by the lateral

paris of tl al latera.

tral latus is of an irregular shape, iis basal margin being short and going
into the latera] margin which is convex. The scutal margin is slightly hollowed
the angle il describes with the lateral margin truncated.

■■ i n tra - m cd i a i) latus is triangular with the rostral margin slightly hollowed oul
and the carinal margin convex. The umbo is at the apex which is distinctly benl forward.

rhe carinal latus has the umbo a little beneath the middle of the carinal margin.
The part of that margin above the umbo is strongly hollowed out, that beneath the umbö
distinctly convex. The basal margin is short, the lateral margin feebly hollowed out. The upper
margin tornis a sharp angle with the upper pan of the carinal margin. That part of the latter
where the umbo is situated can hardly l>c said to project beyond the line of the carina.

General remark concerning the form of the valves. The form of the
valves as described above only appears alter a good deal of the feltlike membrane with the
calcareous algae and the muddy particles attached to them has heen removed.

The peduncle is cylindrical. The scales on the surface are not very numerous, broad
and rather prominent. They are placed on five not very regular rows, about fïve scales forming
such a row.

Si /e. Length of the whole animal 11,25 mm., of the capitulum 8 mm.

The specimens of this species wen- found attached to cylindrical black sticks of tour or
five centimeters in length, the nature of which I do not know.

The study of the structure of the female animal contained within the capitulum has
eriven the following results.

Body narrow, elongated, legs relatively stout.

Mouth with the labrum slightly bullate, edge with a Ion- row of small, pointed teeth.
Palpi triangular, pointed, with a few short hairs on the inner side and a tuft of longer ones
at the extremity.

Mandibles short, with three teeth, each slightly swollen at the extremity. The inferior
angle is delicately pectinated and the surface over a great part is covered with very thin hairs.
forming groups ol three or more.

Maxillae with a distinct notch beneath the group of upper spines. which consists 0f
011e very stout spine, one rather stout and one or two much more delicate. Beneath the notch. in
which only some ver) short hairs are planted, the edge bears about seven spines of unequal size
and a few very delicate and much shorter spines. Surface covered with hairs, arranged in groups.

5 riiiul maxillae bulky; outer surface rounded covered by numerous lono- hairs.
forming a tuft at the upper extremity. The opening giving entrance to the body cavity is at
end of a broad and flat tubular process, cut off abruptly at the extremity.

Cirri. First pair planted close to the mouth, separated from the second by a distinct

pace. branches of the first pair '<\ unequal length, the shorter is slightly broader and has

1. tlv longer nine segments. Nearly the whole surface of both rami is covered with numerous

and rather long hairs. Cirri of the following pairs relatively short and stout; the rami of

96

97

the last pair have about 15 segments, the lower being very long and representing two or
three segments. Two or three pairs of spines on the front of each segment and a third or fourth
pair much more delicate.

Caudal appendages minute, one-jointed, cylindrical, with the extremity rounded.
One long and two or three much shorter hairs planted at the extremity.

The animal as here described is a female with no tracé of a penis.

Males, two; one lodged in a pouch situated on the inner side of each scutum near
the occludent margin, the capitular pole slightly projecting out of the opening of the pouch.
Shape oval, longest diameter 0,8 mm., shortest 0,4 mm. Structure very simple as in many other
deep-sea species. Surface naked, not covered with hairs or short spines. No tracé of valves.
Prehensile antennae attached at a little distance from the peduncular pole. Muscle-fibres of the
sac very distinct, opening of the sac hardly visible.

H. M. S. "Siboga" collected this species at:

Stat. 45. March 6, 1899. Lat. y° 24' S., Long. Ii8°i5'.2-E. Depth 794 m. Bottom : fine grey
mud. Five specimens.

Observation. This species might also be considered as belonging to the group with

imperfectly calcified valves. It has some resemblance to Sc. insigne mihi from the Atlantic; it

can be distinguished from that species at first sight, however, i" by the shape and condition

of the tergum, which is V-shaped in Sc. insigne, 20 by the presence of a rostrum, which is

wanting in Sc. insigne and 30 by the form of the carina.

22. Scalpcllum luimilc n. sp. PI. VIII, Fig. 2 and 2a.

Valves fourteen, not covered by membrane. Scutum very large, of an irregular triangular
shape. Carina simply bowed with the umbo at the apex and with a flat roof borderecl by ridges.
Rostrum extremely small. Infra-median latus with the umbo near the base, with the under part
very narrow and the upper part rhombiform. Carinal latus with the umbo below the middle
of the carinal margin, projecting beyond the line of the carina.

This deep-sea species is represented by a large and a smaller specimen.

The c a p i t u 1 u m is flat and rather broad, the length being slightly less than twice the
breadth, where it is broadest. The carinal margin is more strongly convex than the occludent
margin. Valves separated by narrow interspaces, that between the carina and the other valves
being broader. The surface of most of the valves is delicately furrowed; ridges of growth not
very distinct.

The scutu m is large ; its occludent margin is straight in the under and distinctly convex
;n the upper part. The tergal margin is convex and slightly hollowed out near the apex which
is produced into a very small triangular process overlapping the tergum. The lateral and basal
margins slope into one another forming an arch; at the upper extremity a short part of the
lateral margin forms a triangle with the extremity of the tergal margin.

The tergum is triangular and rather elongated in consequence of the slightly convex
occludent margin not being very long. A small excrescence at the carinal margin above the
point where the apex of the carina touches the tergum.

97

SIBOGA-EXPEDITIE XXXIff. Ij

98

The carina is simply and not very strongly bowed; umbo al the apex. kont' H.it

not increasing much in width trom the upper to the lower extremity, bordered bj distinct ridges.

out the same width over the whole length of the carina.

I'lic upper latus has six margins, the sent. il margin being divided into two parts,

rather short and straight the other larger and hollowed out. The umbo is at the angle

where these two lateral margins meet. I lx- tergal margin is straight, also the short carinal

margin. The lateral margin is divided into two parts: a larger which is hollowed out and

irates the valve trom the carinal latus and a much shorter part between il and the infra-

median latus.

Ilx- rostrum (fig. 2a) is ,m extremely small valve situated in the corner where the
two scuta and the two rostral latera mi

The rostral latus is irregularly quadrangular ; the rostral and lateral margins are
both convex, the second is longer than the first.

Ihe infra-median latus has the umbo near the base. The middle part is narrow
with the foot slightly broader and the upper part distinctly expanded.

The carinal latus is large. The umbo is at the foot of the carina, where the carinal
margin forms a distinct protuberance bevond the edge of the carina. The larger part of the
carinal margin is above the umbo and is distinctly hollowed out, the shorter is beneath the
umbo and convex, h slopes into the short basal margin. The upper and lateral margins are
both slightly convex.

The peduncle is very short and is covered by small and numerous calcareous scales,
placed in eight fairly regular longitudinal rows. Between the scales the chitin of the peduncle
may everywhere be seen.

Size. The total length of the larger specimen is 10,8 mm., that of its capitulum y mm
The smaller one's total length is 7 mm., that of its capitulum not quite 6 mm.

The larger specimen was found attached to a small stick or stem, the nature of which
is unknown to me. It was taken at:

2il. September 25, 1899. Lat. 5°4o'.7S., Long. i2o°45'.5 E. Dcpth 1 158 m. Bottom:
coarsc grey mud.

Observation. But for the shape of the carina this species would have great resemblance
to Sc. distinctum Hoek. The shape of the upper latus and of the carinal latus, however, is also
different; Sc. distinctum has, moreover, no rostrum etc. From Sc. candidum n. sp. to which it
is similar in other regard s it can easily be distinguished by the shape of its carinal latus.

23. Scalpellum arcudtum n. sp. PI. VIII. fig. 3 and 3a.

Valves fourteen. Carina simply and feebly bowed, with a flat roof bordered by ridges.
Upper latus large with a short carinal and long, irregularly bowed scutal margin. Rostrum very
small, triangular. Infra-median latus narrow, with the umbo at the apex. Carinal latus with the
umbo not far from the base.

This true deep-sea form is represented by one specimen only.

98

99

The capitulum is flat with the carinal side slightly and the occludent side strongly
arched. It is covered by a thin membrane, which bears short hairs along the carina, forming
tufts at the base of that valve and in a less degree at the apex. The carina is separated
from the other valves by a distinct chitinous interspace. The valves of the lower whorl are less
than medium-sized.

The scutum is quadrilateral and more than twice as long as broad. It has an arched
occludent margin ; its tergal margin is short ; its lateral margin slightly hollowed out in the
upper part and strongly convex in the lower. The apex is pointed, but not produced. Growth
ridges indicated, but not distinct.

The ter gum is large, triangular, with the occludent margin straight. It meets the carinal
margin in a very slightly produced little point. The carinal margin is straight in the upper,
feebly convex in the under part. Ridges of growth very indistinct.

The carina is simply and not strongly bowed. The roof is flat, increasing in width
from the apex downwards, bordered by ridges. The lateral parts rather narrow and having
about the same width over the whole Iength.

The upper latus is large and has a somewhat irregular shape. Its umbo is at the
apex which penetrates into the corner between the scutum and the tergum. It has a long scutal
margin, slightly convex in the upper and strongly hollowed out in the under part. The carinal
margin is short; the lines of growth are rather indistinct.

The rostrum (fig. 3a) is very small and triangular; it is placed in the corner between
the tips of the rostral latera and the scuta.

The rostral latus quadrilateral, rather small, as is also the case with the other valves
of the lower whorl.

The infra- media n latus very narrow, with the umbo at the apex, very slightly
increasing in width downwards.

The carinal latus has the umbo near the base. It can hardly be said to project
beyond the line of the carina. The upper part is triangular and fits into the angle between the
carina and carinal latus.

The peduncle is short, broader in the upper part. The scales are broad and narrow:
they are irregularly distributed over the surface.

Size. The total Iength of the animal is 9 mm., that of the capitulum 7,5 mm.

The only specimen is attached to a small stick or rod, the nature of which I cannot

make out. It was taken by H. M. S. "Siboga" at:

Stat. 295. January 24, 1900. Lat. io°35'.6S., Long. i24°u'.7E. Depth 2050 m. Bottom: fine
grey mud.

Observation. This deep-sea form comes nearest to the species I describe on p. 105

as Sc. gracile. I consider the two forms as different not so much because a rostrum is present

in the one and wanting in the other species, but especially because the valves of the lower

whorl are much more developed in Sc. gracile than is the case in the present species. The

carinal margin of the carinal latus is moreover slightly more hollowed out in Sc. arcitatum than

in Sc. gracile.

99

,:ilui>i n. sp. PI. VIII, !i. | .nul |</.

Valves i | not covered by membrane. Carina simply bowed with a flat rooi', bordered

listinct ridges. Upper latus pentagonal with the umbo al tin- apex; apex produced. Rostrum

narrow, slightly broader .it the upper extremity. Infra median latus irregularly wine-glass shaped,

with the umbo near the base. Carinal latus with the umbo nol far from the l>ase. Peduncle

. short

rhis species is represented bj one specimen only.

rhe capitulum is il.n, broadest about the middle of the scutum, slightlj narrower

towards the luis.-, distinctly pointed towards tin- upper extremity. The carina is not strongly

• 1. so that the whole capitulum looks ;is il" slightly recurved. No membrane covers the valves.

rhe se 11 tu m li. is the ordinary shape; its occludent margin is strongly arched. It is

about twice as long as broad. I'lu- apex is slightly produced and overlaps the tergum.

The tergum is rather large; the occludent margin is nearly straight, tin- scutal margin
also straight, tin- carinal margin slightly convex beneath and slightly concave above the middle.
rhe apex <>( the carina presses very slightly into the carinal margin of the tergum. Apex
hardly produced. Growth lines visible, luit not ver) distinct.

TIn- carina has a distinct roof and well-developed sides. The roof grows broader from
the apex to the base, tin- sides are broadest in tin- upper part. The umbo is at the apex. The
is flat, bordered 1>\ distinct ridges.

The upper latus is pentagonal, with the scutal and tergal margins by far the longest.
The umbo is at the apex which is distinctly produced. The growth ridges are visible on this
vake more distinctly than on any of the others.

The rostrum (fig. 4</ is very narrow. slightly broader towards the upper extremity.
It does not reach quite so far downwards as the basal margin of the rostral latus.

The rostral latus is quadrilateral. lts lateral margin is convex, its scutal margin
slightly hollowed out. The umbo is at the angle of the rostral and scutal margins.

The infra-median latus lias the shape of a wine-glass, more or less inclined to
one side. Though the name I propose for the species was chosen from this characteristic, I do
not consider the shape of this valve of so essential importance: I aftcrwards discovered that
the right infra-median latus shows by no means the same shape so distinctly as the left.

The carinal latus is rather large with a long carinal margin and the umbo seated
near the base. The lateral margin which is sinuous in the valve of the left side, describes a
nearly re^ular curvature in the same valve of the right side of the capitulum.

The peduncle is very short, the scales are relatively large and not numerous; they
er the whole surface and are much pressed together.

Si ze. The total length of the specimen is 6,6 mm., that of the capitulum 5.,} mm.

["hè "Siboga" collected the single specimen at:

Stat. 300. January 30, 1900. Lat. 10 48'.6 S., Long. 123 23'.] E. Depth 918 m. Bottom: fine

v mud.

Observation. This curious deep-sea pecies may bc easily distinguished from tin-

IOI

other species of the same group by the shape of the carina, by the rostrum and by the size
and form of the infra-median latus.

25. Scalpellum discolor n. sp. PI. VIII, fig. 5.

Valves thirteen covered by membrane. Tergum triangular, with the occludent margin
nearly straight and the carinal margin convex. Carina simply and not strongly bowed with the
umbo at the apex; roof flat bordered by ridges; sides hardly broader in the upper than in the
under part. Infra-median latus small, with the umbo at the apex and the lateral margins nearly
parallel. Umbo of the carinal latus at a short distance from the base, not projecting beyond
the line of the carina. Scales of the peduncle covering one another like the tiles of a roof.

This species is represented by one specimen only.

The capitulum is rather flat, broad, less than twice as long as broad. The carinal
and rostral sides are nearly equally convex; the occludent margin of the scutum forms an angle
with the nearly straight occludent margin of the tergum. Valves covered with a yellowish membrane
which is here and there distinctly pigmented with darker brown. The ridges of growth are very
distinct in most of the valves, the furrowing of the surface less distinct in most.

The scutum is elongate with the umbo at the apex. The apex is produced, but can
hardly be said to project over the tergum. The occludent margin is feebly convex, the tergal
and basal margins are of about the same length, the lateral margin is strongly convex with a
small excavation near the upper extremity for the reception of the apex of the upper latus.

The tergum is triangular with the occludent margin nearly straight. lts carinal margin
is convex and shows a tracé of an angular excrescence above the point where the apex of the
carina touches the carinal margin. About V.t'd of the carinal margin extends beyond the apex
of the carina.

The carina is simply and not strongly bowed, with the apex at the umbo. The flat
roof increases in breadth from the apex to the base and is bordered by distinct ridges. The
sides of the carina do not increase in breadth from the lower to the upper half of the valve.

The upper latus has the umbo at a little distance from the apex, which forms a
pointed excrescence entering into the angle between the scutum and the tergum. The scutal
margin is strongly hollowed out. The shape of the valve is pentagonal.

The rostral latus is quadrilateral with the scutal and basal margins of nearly
equal length.

The infra-median latus is also quadrilateral. It has the umbo at the apex in the
corner where the four valves: the scutum and three latera meet. lts rostral-lateral margin is
hollowed out, its carinal-lateral margin nearly straight.

The carinal latus has the umbo near the base at the carinal margin, which can
hardly be said to project beyond the line of the carina.

The peduncle is short, truncated, conical. The scales cover one another like the tiles
ot a roof. They are not very numerous and arranged in 8 or 9 longitudinal rows.

Size. The total length of the specimen is 18,6 mm., that of its capitulum 14,5 mm.

n>:

The single specimen was collected

N . mbei 4., 1899 Lat. 1 24 S., Long. 124 .1 Dépth 2798 m Bottom: solid,
bluish grey mud with Foraminifcrae.

Observation. This species is no doubt nearly related to Si . trapezoideum n. sp. and
t,. Sc. truncatum Hoek. Under Sc. trapezoideum 1 give the reasons why I tliink it better to
consider them .is three different species. Scalpellum truncatutn Hoek was collected by the
-1 hallenger" .1 single specimen also at a depth of 2520 m., 12 8'S.L. and 1 15 ' io' E.L. and
therefore maj also be considered as au inhabitant "f the Indian Archipelago.

5 alpellum trapezoideum n. sp. PI. VIII, fig. 6.

Valves thirteen not covered by membrane. Tergum with the occludent margin straight
and tlu- carinal margin distinctly divided into tw<> parts. Carina simply and not strongly bowed
with the apex at the umbo; roof flat bordered by ridges; sides considerably broader in the
upper than in the lower part. Infra-median latus narrow with the umbo at the apex, hour-glass
shaped. Umbo of the carinal latus near the base, slightly projecting beyond tlu- line of the
carina. Scales of the peduncle narrow. at some distance from one another, projecting beyond
the surface.

This species is represented by one specimen only.

The capitulum is broad, much loss than twice as long as broad, flat in the upper,
thicker in the lower half: the straight occludent margin of the tergum forms an angle with the
ludent margin of the scutum. Valves not covered by membrane, surface showing the growth-
ridges, but not so distinct as the furrows.

The scutum is elongate, with the umbo at the apex. The apex is very slightly produced,
but cannot be said to project over the tergum. The form of the scutum is nearly the same as
in Sc. discolor, the lateral margin being however not so strongly convex.

The tergum has the shape of a trapezium: the perfectly straight occludent margin forms
an angle of about 8oc with the upper part of the carinal margin, which runs nearly parallel to
the scutal margin. The length of this part of the carinal margin is about ' ,l!' the whole length
of that margin: where it meets the much longer and slightly convex lower part of the same
margin a small excrescence is formeel, just above the place where the apex of the carina
touches the tergum.

The carina is simply and not strongly bowed, with the umbo at the apex. The flat roof
increases considerably in width from the apex to the base and is bordered by distinct ridges.
The sides of the carina are considerably broader at the upper extremity than in the lower part.

The upper latus has the umbo near the apex, the scutal margin hollowed out and
the carinal margin very short. It is pentagonal as it has a short basal margin separating it
from the infra-median latus. and a rather long basal margin along the carinal latus.

The r<>stral latus i-, quadrilateral with the upper and basal margins of about the

fth.
The infra median latus is narrow; its shape is that of an irregular hour-glass. the

upper part being smaller than the lower part. The umbo is at the apex in the corner where
the scutum, the upper latus, the rostral and infra-median latus meet.

The carinal latus is rather large. The umbo is at a short distance from the base,
that part of the carinal margin slightly projecting beyond the line of the carina.

The pe du nel e is short, truncated, conical, with very prominent scales placed at some
distance from one another in five not quite regular longitudinal rows.

Size. The total length of the specimen is 24 mm., that of its capitulum 17,7 mm.

It was found attached to a piece of black stone, the nature of which is unknown to me.

The only specimen was collected at:

Stat. 214. October 27, 1899. Lat. 6° 30' S., Long. I2I°55'E. Depth 2796 m. Bottom: grey
and green mud.

Observation. This species is nearly related to Sc. discolor n. sp. and to Sc. truncatum
Hoek. It differs from the last-named species by the absence of the rostrum, by the shape of
the infra-median latus and also by the less truncated form of the tergum. From Sc. discolor it
differs by the nakedness of the valves, by the form of the tergum and by the more distinct
furrows on the surface of the valves. The shape of the infra-median latus and that of the scales
of the peduncle are also different. As there is only one specimen of Sc. trapezoideum and one of
Sc. discolor at my disposal, future investigations will have to determine whether these differences
have really the importance of specific characteristics.

27. Scalpellum proclivc n. sp. PI. VIII, fig. ja.

Valves thirteen. Surface nearly smooth. Margins of valves distinct. Carina with a flat
roof, bordered by ridges. Valves of the lower whorl rather large. Infra-median latus with the
umbo beneath the middle and the upper part growing broader towards the tip. Carinal latus
with the umbo at a short distance from the base, the two parts of the carinal margin meeting
at an obtuse angle.

The capitulum is elongate, more than twice as long as broad. Carinal side about as
strongly bowed as the rostral side. Apex of the tergum produced and feebly recurved. The
surface of the capitulum is nearly smooth and the margins of the valves can be easily made
out in consequence.

The scutum is quadrilateral, with the apex produced. The occludent margin is con-
siderably longer than the lateral margin, the tergal margin is longer than the basal margin.

The tergum is triangular. lts occludent margin is nearly straight; it meets the carinal
maro-in at a sharp angle, so that the apex appears to be produced. The carinal margin is
straight in the upper and distinctly convex in the lower part.

The carina is long, reaching to V*th the length of the carinal margin of the tergum
from the apex of that valve. It is rather strongly bowed with the umbo at the extremity. It
has a flat roof, bordered by ridges, and distinct sides, which have about the same width all
over their length.

The upper latus is pentagonal. The umbo is at the apex, near the angle where the

i°3

il and scutal margins meet. The scutal margin is feebly hollowed out. The short 1

. this valve from the infra median latus, the < »th«r. longer basal margin separates
latus from the carinal latus.
rhe rostral latus is quadrilateral ; its rostral and lateral margins are longer than its
upper and basal margins.

rhe infra-median latus has the umbo below the centre. The lower part <>l the
valve is narrow and small, the upper pari grows broader towards the upper extremity.

The carinal latus is rather large. The umbo is near the base at the tip of a part

of the carinal margin which projects slightly beyond the line ol the carina. The remaining and

• part of the carinal margin is very slightly hollowed out for the reception of the carina.

rhe peduncle is cylindrical. Its length is about ' ■' that of the capitulum, its width

is about • its length. It is covered with distinct, rather large scales of regular form, arranged

in si\ longitudinal rows. The number of scales in each longitudinal row is about i8.

Si; rhe total length of the specimen representing this species is 9,1 mm., that "f
the capitulum 6,8 mm.

It was found along with Sc. deforme attached to the same small stem of a Tubularian al

Stat. $-. June 1 Lat. o 32 S., Long. 119 39'.8 E. Depth 655111. Bottom : fine grey mud.

28. Scalpellum deforme n. sp. PI. VIII, fig. -/>.

Valves thirteen. Surface covered with a hairy membrane, the margins of the valves not
distinct in consequence. Carina simply luit very feebly bowed, laterally convex, roof and sides
not separated by ridges. Valves of tin- lower whorl rather small. Infra-median latus narrow with
the umbo at the apex. Carinal latus with the umbo at a short distance from the base.

The capitulum is clumsy in shape, nearly as broad at the base as in the middle,
than tuier as long as broad. Carinal side feebly. rostral side strongly bowed. Apex of the
tergum hardly produced but distinctly recurved. The surface of the capitulum is covered by
membrane, which is feldike and distinctly hairy along the carina.

The scutum is quadrilateral, large. The apex is somewhat produced and distinctly
recurved. Tergal margin about as long as the basal margin.

The tergum is triangular and also large. The occludent margin is bowed and meets
the carinal margin at a nol ver) sharp angle; this apex is distinctly recurved. The carinal
margin is straight in the upper and convex in the lower part.

The carina is feebly bowed, not very long. It reaches to about ' "' the length of the
carinal margin of the tergum from the apex <>f that valve. The umbo is at the apex. It has
no flat roof, being laterally convex and the roof sloping insensibly into the sides.

The upper latus is large, quadrilateral, with a very short carinal and a very long scutal
margin. This latter margin is strongly convex in the lower and slightly convex in the upper
part. Where the two parts meet a depressed angle is formed. The tergal margin is somewhat

than the basal margin. The apex is slightly produced; the umbo is at the apex.

tral latus is rather broad, bul not high. The upper and basal margins are

104

i°5

considerably longer than the rostral and lateral margins. Where the upper and rostral margins
meet the umbo is seated, that part of the valve being distinctly produced.

The infra-median latus is small, very narrow, elongated with the umbo at the apex.

The carinal latus is trapeziform, with a short lateral and a much longer carinal
margin. The umbo is near the base; it hardly projects beyond the carina; the upper part of
the carinal margin is only very indistinctly hollowed out for the reception of the carina.

The peduncle is thick, short and laterally flat. lts length is only a little greater than
its width and is less than '//d the length of the capitulum. It is covered with rather flat but
broad scales, the margins of which are not very distinct.

Size. The total length of the specimen representing this species is 10,5 mm., that of
the capitulum 8 mm.

The specimen was found along with Sc. proclive attached to the same small stem of a
Tubularian at :

Stat. Sy. June 19, 1899. Lat. 0°32'S., Long. ii9°39'.8 E. Deptl-1655 m. Bottom: fine, grey mud.

Observation. This species belongs to the same group of species or subdivision of
the genus as Sc. proclive, Sc. gracile, Sc. Novae-Zelandiae and a few more. It will be for
future investigators to settle whether or not we are entitled to consider them as so many
different species.

29. Scalpclhtm gracile n. sp. PI. VIII, fig. 8.

Valves thirteen, covered by a thin membrane. Scutum rather narrow, its tergal margin
less than half as long as the tergal margin of the upper latus. Carina with the umbo at the
apex, with a fiat roof bordered by not very prominent ridges and with the sides narrow. Upper
latus large, almost triangular owing to the carinal margin being very short. Infra-median latus
elongate, very narrow. Carinal latus with the carinal margin nearly straight and the umbo at
a short distance from the base.

This species is represented by three specimens.

The capitulum is flat, oval, twice as long as broad, with the occludent margin as
strongly (or slightly more) arched as the carinal margin. The surface of the valves is covered
by a thin membrane, to which small particles of mud etc. adhere. Hence the surface has a
yellowish colour-, the valves are delicately furrowed, but the furrowing is visible only after the
surface has been cleaned with a small brush or pencil. Valves of the lower whorl rather large.

The scutum is elongate, more than twice as long as broad. The occludent margin is
distinctly bowed, the lateral margin hollowed out in the upper and convex in the lower part.
The tergal margin is short; it meets with the occludent margin at the apex, where a small
triangular projection is formed which slightly overlaps the tergum.

The tergum is large, triangular. The occludent margin is convex, the scutal margin
nearly straight. The carinal margin is convex, with the exception of the upper part which is straight
and which meets with the occludent margin at a sharp angle : the apex is slightly recurved.

The carina is simply and not strongly bowed. Its umbo is at the apex. The roof is

SIBOOA-EXPEDITIE XXXI <?. 14

irrow and is bordered b) ridges vvhich are not prominent. I 'In- sides are also narrow, only
slightly increasing in width from below upwards.

TIn- upper latus is large with the ape* produced, entering into th<: narrow angle

tween the lateral margin of the scutum and the scutal margin of the tergum. The shape ol

the valve is triangular, one of the angles is, however, truncated by the shori carinal margin,

and another, the basal, by the very short basal margin between this valve and the rostral

latus. rhe umbo is ;it a little distance from tin- apex, close to the scutal margin.

The rostral latus is quadrilateral and rather high. The angle formed by the scutal
and lateral margins is truncated and the valve at that angle is in contact with the upper latus.

The i nfra-median latus is narrow and elongate with the umbo at th< perior
extremity. The latter touches the upper latus.

The carinal latus is quadrilateral. The carinal margin is the longest; it is nearly
straight, only very feebly hollowed out in the upper pan for the reception of the lower extremity
the carina. The umbo is at a short distance from the base. The lateral margin is straight,
upper margin sh'ghtly convex.

The peduncle is nearly cylindrical, compressed laterally. The scales are thin and
broad and rather prominent. They are placed in five Iongitudinal rows, each row having
ut fi ft een.

Size. The whole length of the largest specimen was 13,6 mm., that of its capitulum
10 mm. Th of the other specimens was but slightly different.

The study of the animal contained within the capitulum has yielded the following results:

Mouth. The labrum has the In uu part somewhat bullate, forming a rounded slightly
overhanging projection; crest with very minute teeth; palpi short and broad, rounded at the
extremity, where about half a dozen hairs are planted.

Mandibles with three teeth and the inferior angle pectinated; the distance betw<
the tips o( the lirst and second tooth equals that between the tips of the second and third and
of the third to the inferior angle.

Maxillae with the edge perfectly straight; about the middle the edge has an interspace
without spines, four spines (two large, one smaller and one very small) being inserted above the
interspace and about six rather short spines, only one of which is longer than the others, below.

('uter maxillae rounded, bristles in two separate groups. Openings giving entrance
to the body cavity at the end of long, flat processus, cut off transversely at the extremity.

Cirri. First pair attached near the base ol the mouth and at a little distance from
the second pair-, rami very unequal, the shortest having 7 to 8 very broad segments, soldered
tightly together, so that the limits can only he distinguished with difHculty; the longer ramus
has 9 much narrower segments, the lirst of which is very long. The shape of the shorter ramus
.is a whole is leaf-like, that of the longer cylindrical. Both rami are covered with numerous
and long spine-like hairs.

ond pair elongate, also with unequal rami: the shorter has 12, the longer ramus

jments. In both rami the firsl segment is very long, the 3 or 4 following are nearly

quadrilateral, the fifth growing longer and slightly narrower. until the last are very elongate

106

and narrow. The segments bear numerous spines all over the surface and also 3 to 5 pairs of
Ionger ones along the anterior margin.

The cirri of the 3"1 to 6th pair have extremely elongate and narrow rami. Th o se
of the 6lh pair have rami of about 23 segments, which are all long and narrow but of which
the middle ones (from the 8lh — iSth) are by far the longest and bear the greatest number
(5 pairs) of spines along the anterior margin.

Caudal appendages elongate, narrow, reaching to the end of the pedicel of the
sixth cirrus, composed of five cylindrical segments, each having a few long hairs at the extremity.
At the end of the fifth segment half a dozen hairs are planted, three of which are very long
and measure about the length of the three last segments of the caudal appendage.

No tracé of a penis.

The specimen I investigated was furnished with a cluster of eggs attached to the inner
side of the sac or mantle ; the animal was not in a good state of preservation, and I can only
say that the eggs seemed to form but one cluster. There were in all 53 eggs, the size of which
was about 0,5 X 0,33 mm., their shape being oval. The colour of the (preserved) eggs was
dark orange. The volk of these eggs was composed of rather large spherical globules.

I observed two small mal es, one on each side at the ordinary place. They were in
a bad state of preservation. Their length was 0,8 mm., they were more than twice as long as
broad. The little animals were, however, distinctly shrivelled, therefore narrower, most probably,
than they would be in the living condition. Round the opening giving entrance to the sac four
small calcareous plates were observed, two small and two slightly larger, all of them of oval
shape. The rest of the surface is covered with very minute spine-like hairs which are placed in
transverse rows. The prehensile antennae are attached at about one third the length of the
animal from the peduncular pole.

This species was collected by H. M. S. "Siboga" at:

Stat. 211. Septbr. 25, 1S99. Lat. 5°4o'.7 S., Long. I20°45'.5 E. Depth 1158111. Bottom: coarse
grey mud.

Observation. This species is nearly related to Sr. oóesum\ the form of the capitulum
as a whole and the greater height of the valves of the lower whorl, together with the difterent
shape of the peduncle and its scales make it necessary to consider them as different species.
The present species also shows affinity to Sc. incertum and to Sc. arciiatuni, which, however,
are both species with a rostrum.

30. Scalpelhivi clegans n. sp. PI. VIII, fig. 9.

Valves (14) 13, covered here and there by membrane, beautifully striated. Carina simply
bowed, with the umbo at the apex and a flat roof bordered by ridges. Upper latus trapeziform.
Valves of the lower whorl well-developecl, with exception of the narrow, triangular infra-median
latus. Rostrum hardly visible, represented by an extremely narrow streak. Umbo of the carinal
latus a little below the middle of the nearly straight carinal margin.

This beautiful species is represented by one specimen only.

107

tpitulum is elongate, twice as long as broad, rather tl.it . lts occludent margin

is nearly straight, its carinal margin stronglj arched, [*he apex of the tergum is pointed. The

■t' the valves is here and there, especiall) at the occludent side, covered with membrane,

ing short hairs, There is .1 distinct chitinous interspace between the carina and the other

rhe valves "f the lower whorl are stronglj developed; the upper margin ol the carinal

latus is the prolongation of the same margin of the rostral latus.

The scutum is quadrilateral, about twice as long as broad. lts lateral and occludent
margins are parallel and nearly straight. Where the occludent and ter fal margins meet the
htly pointed and recurved apex projects over the tergum.

The tergum is triangular, with the scutal margin straight, the occludent margin also
straight, the carinal margin slightly convex in the lower part, nearly straight in the upper. The
ie pointed, but hardly produced.

The carina is strongly bowed, with the umbo at the apex. It lias a flat roof bordered
by i and increasing in width, but not very considerably, from the apex downwards. The

I the carina are flat; their width in the middle is slightly less than near the upper and
under extremity.

The upper latus is trapeziform; its tergal and basal margins are of equal length,
utal margin is twice as long as its carinal margin. The umbo is at the apex which very
slightly projects over the scutum.

The rostrum is hardly visible; as the rostral margins of the rostral latera do nut
touch one another and as an extremely narrow streak of probably calcareous matter is
longitudinally in the middle of this interspace, there is reason to consider this as representing
the rostrum.

The rostral latus is quadrilateral and rather high. Its rostral and lateral margins
are convex, its upper margin hollowed out, its basal margin short and straight.

The infra-median latus is triangular, narrow, with the umbo at the apex. It is
considerably less in height than the other latera, so that the lateral margins of the rostral and
carinal latus meet above the apex of the infra-median latus.

The carinal latus is elongate, trapeziform. Its carinal margin is the longest. It is
slightly hollowed out in the upper half where the carina rests against it, and straight below
the umbo. Its lateral and upper margins are of equal length and straight; its basal margin is
the shortest.

All the valves, the carina excepted, are: beautifully and delicately striated.

The peduncle is cylindrical and short. It is covered by well-developed scales which
overlap each other like the tiles of a roof.

Size. The length of the whole animal is 20,5 mm., that of the capitulum 15,5 mm.

The animal is attached to a long tube in the form oi a spiral, the dwelling-place probably
of a tubicolous annelid.

The specimen was collected by II.M.S. "Siboga" at

■ mber 22, 19. Lal I I22°i2 E. Depth [886 m. Bottom: solid

11 mud.

ioN

109

Observation. This species has some resemblance to Sc. vitreum Hoek collected by
the "Challenger" not far from Yeddo, in Japanese waters. The form of the whole capitulum,
that of the carina and the rostral latus show, however, its distinctness.

31. Scalpellum sculptum n. sp. PI. VIII, fig. 10.

Valves fourteen, not covered by membrane, beautifully grooved. Carina with a flat roof
bordered by distinct ridges, short, hardly surpassing in length the carinal margin of the tergum.
Rostrum small triangular. Other valves of the lower whorl high. Infra-median latus narrow,
rectangular, with the umbo at the apex. Carinal latus pentagonal, with the umbo above the
middle of the carinal margin.

This pretty species is representecl by one specimen only.

lts capitulum is elongate and nearly equally convex on the carinal and rostral sides.
It is not flat, the carina having a broad roof and the scuta being moreover rather convex.
The valves are not covered by membrane but show a very fine sculpture of parallel grooves
all over their surfaces. There are no membranous interspaces between the valves. The valves
ot the lower whorl are strongly developed.

The scutu m is quadrilateral ; its occludent margin is strongly convex, its basal margin
nearly straight and much shorter than the tergal margin. The lateral margin is also straight
with a slight deviation near the upper extremity.

The tergum is large, triangular. Its occludent and scutal margins are straight, its
carinal margin is feebly hollowed out in the upper and slightly convex in the lower part. The
apex is slightly produced and recurved.

The carina is short, simply and not strongly bowed, with the umbo at the apex. The
roof is flat, increases greatly in width from above downwards and is bordered by distinct ridges.
The sides in the superior part are rather broad and at angles greater than 900 with the roof.
They are distinctly furrowed in this part.

The upper latus is trapezitorm and has the four margins nearly straight. The scutal
margin is the longest; where it meets with the tergal margin the apex is truncated. Here the
umbo forms a pointed, hardly distinguishable projection.

The rostrum (fig. \od) is very small and of a triangular shape. It is not covered
laterally by the rostral latera.

The rostral latus is quadrangular with the rostral and lateral margins of nearly equal
length. Its upper margin is feebly hollowed out, its basal margin is short and straight.

The infra-median latus is narrow and elongate. It has the umbo at the upper extremity
and as it has about the same breadth all over its length the shape may be given as rectangular.

The carinal latus is pentagonal, owing to its carinal margin being divided into two
parts of unequal length which form together an obtuse angle. The umbo is seated at this angle,
at the tip of the lower and longer part of the carinal margin. The upper part of this margin
is very slightly notched to receive the basal extremity of the ridge which borders the roof of
the carina. The upper and lateral margins of the carinal latus are of about the same length.

109

The umbo of the carinal latus «.!< ><■-• n«<t project beyond the line of the carina. The right and
left carinal latera meel over the w h<»l«- length of the lower part of the carinal margin.

peduncle is very short and completely covered by rather large scales, forming
si\ longitudinal rows, About six scales are present in each row.

Size. rhe total length of the specimen representing tliis species is 7,6 mm., the capitulum
alone measuring 6,2 mm.

The specimen was taken by ll.M.S. "Siboga" at:

St.u. 221. November 4. 1 .1 at. 1 .■ ; S.. Long. 124 59 E. Depth 2798 m. Bottom: solid
bluish grey mud with Foraminif* ra.

irvation. This species shows some resemblance to Sc. vitreum dredged by the
'Challenger" near Yeddo from a depth of 1 s 7 5 fathoms (about 3375 m.). The general habitus,
the sculpture of the surface oi the valves, the structure of the carina and the large si/c of the
valves of the lower whorl are nearly equal in both species. But in Sc. vitreum no rostrum was
served; its infra-median latus is triangular and much shorter than the other valves of the
lower whorl: finally, the carinal latus has the umbo at one fourth of the total length of the
carinal margin from the inferior extremity, not above the middle of that margin as is the case
in Sc. sculptum. Under similar circumstances (bottom mud, depth • 3000 mi, from perhaps
similar ancestors, two forms have developed, the distinctness of which can not be doubted
though their resemblance is equally striking.

;2. Scalpdlum formosum n. sp. PI. VIII, fig. 11 and 1 w?.

Valves fourteen, not or but very indistinctly covered by membrane, beautifully striated.
rergum with the apex produced and pointed. Carina simply bowed, with die umbo at the apex,
with a flat ro<.f bordered by ridges and with the sides well-developed. Upper latus trapeziform.
Rostrum elongate, very narrow. Valves of the lower whorl well-developed. Infra-median latus
triangular. Carinal latus pentagonal, the carinal margin consisting of two parts, forming an
angle where they meet.

This fme deep-sea species is represented by two specimens collected at two different Stations.

The capitulum is elongate, rather flat, with the occludent margin slightly more
nvex than the carinal margin and the apex produced and pointed. The length of the capitulum
is about twice its breadth.

The scutum is large, quadrangular, with the occludent margin strongly convex and
the lateral margin straight. The tergal margin is a little longer than the basal margin and
meets the occludent margin at the slightly recurved apex which overlaps the tergum.

The tergum is triangular: its occludent margin is straight, or even slightly hollowed
out (as in the specimen figured). The scutal margin is straight and so is the carinal margin
with a little convexity in the lower part only. About a third of the carinal margin projects
beyond the apex of the carina.

The carina is simply and not very strongly bowed, with the umbo at the apex and
with a roof and well-developed sides. The roof is rather broad at the base and is bordered by
distinct ridges. The sides increase but slightly in width from the base upwards.

no

I I I

The upper latus is trapeziform. The length of the carinal margin is less than half the
length of the scutal margin. The tergal margin has about the same length as the basal margin.

The rostrum (fig. iu) is elongate, narrovv. It is almost entirely covered (especially
so in the specimen from Station 227) by the lateral parts of the rostral latera.

The rostral latus is irregularly quadrangular. lts rostral margin is shorter than its
lateral margin, its basal margin much shorter than its scutal margin.

The infra-median latus is triangular and has the umbo at the apex. The latter
does not quite reach to the slightly truncated scutal-basal angle of the upper latus. The height
of this small valve is slightly greater in the specimen from Station 241 than in that from
Station 227.

The carinal latus has a pentagonal shape, with a short basal margin, a convex
lateral margin, and a straight upper margin. The umbo is below the middle of the carinal
margin, the two parts forming an angle together. The upper part is slightly hollowed out at
its base where the under extremity of the carina rests against it.

All the valves are beautifully striated. The striae radiate, as a rule, from the umbo over
the surface of the valve. The ridges of growth are very indistinct; traces of them may be seen
on the scutum and the upper latus.

The peduncle is short, cylindrical. The surface is covered by scales placed on a few
lono-itudinal rows. One of these rows on each side has more prominent scales and the number
of scales composing it is six or seven. The peduncle of the specimen from Stat. 241 was found
attached to a small piece of black stone (like lava) : the other specimen is attached to a small,
greyish, calcareous stone.

Size. The total length of the specimen from Station 241 is 14,3 mm., the capitulum
alone measuring 11,3 mm.

The two specimens representing this species were collected by H. M. S. "Siboga" at:

Stat. 227. November 13, 1899. Lat. 4°5o'.s S., Long. i2/°59'E. Depth 20S1 m. Bottom: grey
mud with an upper layer of brown mud, both mixed with sand.

Stat. 241. December 1, 1899. Lat. 40 24'. 3 S., Long. i29°49'.3 E. Depth 1570 m. Bottom: dark
sand with small stones.

Observation. The two specimens differ from one another in that the rostrum is
much narrower in the one than in the other, as also that the shape of the tergum and the
size of the infra-median latus are not alike. But I consider the points of agreement of greater
importance than these differences. This new species comes nearest to Scalpellum vitreum collected
by the "Challenger" off Yeddo.

33. Scalpellum hcxagonum n. sp. PI. VIII, fig. 12.

Valves thirteen, not covered by membrane. Scutum nearly triangular. Carina simply, not
strongly bowed, umbo at the apex. Roof without ridges, laterally slightly convex. Upper latus
laro-e elono-ate hexaeonal. Rostral latus small : infra-median latus narrovv and very small ; carinal
latus rather large, with the umbo in the middle of the carinal margin.

This new deep-sea species is represented by three specimens.

i i :

ipitulum is elongate, aboul twice as long as broad, flat. Ii is not covered by
membranc and the lines of growth of 1 1 1 * - different valves are not very distinct, Though the
i-ariiia is not strongly bowed, the carinal side of the capitulum is more strongly convex than
the rostr.il or occludent side. There is no rostrum, hence the total number of the valves is
thirteen. The scutum and the upper latus are "f considerable si/c and very peculiar shape

The se u tu in is large; in consequence ol the shortness of the basal margin the shape
ui' the scutum is almost triangular. The occludent margin is straight, only feebij convex in the
upper part. lh<- tergal margin is rather long; it forms a small slightly recurved apex with the
occludent margin. The lateral margin lias a iltpri -^s.^-,1 angle slightly above the middle of its length.

The tergum is medium-sized. lis occludent margin is convex; its carinal margin slightly
in the lower and hollowed out in the upper part; its scutal margin is feebly hollowed
out about the middle. The apex of the tergum is distinctly recurved, but blunt, not pointi

The carina is rather long, reaching to ,!i of the length of the carinal margin of the

in. It is not strongly bowed and its sides are only well-developed in the upper part. The roof

increases in width from the apex downwards; it is not bordered by ridges, but laterally convex.

The upper latus is very large and of an irregular, elongate hexagonal shape. The
umbo is almost in the middle of the scutal margin, where a slight convexity fits into the
depressed angle of the lateral margin of the scutum. The length of the different margins can
een in the figure.

The rostral latus is very small. its shape is distinctly pentagonal. Its rostral margin
is considerably longer than the lateral margin, which separates it from the infra-median latus.

The infra-median latus has the umbo at the apex. It is a narrow and relatively
short valve.

The carinal latus is irregularly pentagonal. Its carinal margin is divided into two
\ equal parts at an angle with one another. The upper part is hollowed out for the
ption of the basal part of the carina. The upper margin has a slight excrescence about its
middle point. The lateral margin is the shortest of all.

The peduncle is short, cylindrical, slightly broader at the upper extremity. Its surface
bears rather broad and narrow scales placed in not quite regular rows: one at the carinal and
one at the rostral side alternating with one placed in the middle of the left and one in the
middle of the right side.

Size. The total length ^i the specimen figured is 7.5 mm., that of the capitulum 6,6 mm.

The study of the structure of the animal contained within the capitulum has yielded
the following results:

Mouth slightly bullate. with the part directed forward rounded. Lab rum with a row
of small but distinct teeth, those in the middle of the row slightly larger and distinctly pointed.
Palpi slender, with a few short hairs along the outer margin and a couple slightly longer
ir and at the tip.

Mandibles with three equally distant teeth and the distance between the third teeth
• tinated inferior angle very short.

Maxillae with a distinct notch about the middle of the edge; with four spines. two of

1 1.'

H3

which are longer than the others, above and four beneath the notch. Of the latter, one is much
longer and stronger than the three others. Apodeme moderately long.

Ou ter maxi 11 ae rounded, hairs in three distinct groups; processus with the opening
giving entrance to the body cavity rather long and rounded at the end.

Cirri. First pair with very unequal rami : the anterior indistinctly divided into six
segments, broad, growing narrower towards the extremity, flat: the posterior ramus longer,
composed of eight segments, somewhat cylindrical. In both rami the first segment is much longer
than the following; the last is again rather short. Surface of both rami covered with long bristles.
The first pair of cirri is attached close to the mouth and at some distance from the second pair.

The second pair has nearly equal rami of respectively 12 and 13 segments. The
first segment in both rami is the longest ; next come three or four segments which are only
slightly longer than broad; then five or six segments which grow gradually longer and narrower,
while the remainder are shorter than the foregoing, but narrower. The longest segments have
four pairs of spines along the anterior margin : the first pair short, the second pair slightly
longer, the third rather long, the fourth pair by far the longest and stoutest.

The last pair of cirri has 20 segments in both rami, 13 segments, however, in one
of the rami of the right cirrus. Segments gradually increasing in length, with 3 and 4 pairs
of spines on the anterior margin. The spines of the last segments are extremely long and
distinctly curved.

Ca u dal appendages rather long and narrow, composed of five segments. The end
of the fourth segment reaches to the end of the pedicel of the sixth cirrus. A couple of very
lono- and delicate hairs are planted at the end of the third and fourth segments, half a dozen
at the tip of the 5th segment.

No penis. Animal unisexual. The specimen I investigated was furnished with a cluster of
e ergs, altogether 20 in number, soldered together and attached with two threadlike "ovigerous
frena" to the inner surface of the mantle or sac. The si ze of the eggs was: 0,43 X 0,3 mm.
Their shape was o val.

I found one little male attached to the interior of the left scutum in one of the
specimens and I think I also saw one on the right side of the same individual. The shape
of the one I loosened from the female was broad, oval, its dimensions being 0,55 X 0,4 mm.
I observed the prehensile antennae attached to the sac at a short distance from the peduncular
pole. No tracé of valves. Extremely short and delicate hairs could be seen only at that part
of the surface, which corresponds to the capitular pole. [The little animal was not in a very
good state of preservation — other details of its structure could not well be made out.]

Of this interesting species three specimens were found attached to a much ramified deep-

sea organism of unknown nature. A specimen of Verruca spec. was attached to the same plant.

It was dredged at :

Stat. 221. November 4, 1S99. Lat. 6°24'S., Long. I24°39'E. Depth 2798 m. Bottom: solid
bluish grey mud with Foraminifera.

Observation. This is a very characteristic species. The shape of its scutum is much
like that of Se. distinctum Hoek and Sc. humile n. sp.; in other regards (more elongate form

SIFOGA-EXPED1TIE XXXI (l. ' 5

of its upper latus, smallness and shape of its infra-median latus, form «>t the carinal latus etc.)
the present species is. however, so different, tli.it it can \«- distinguished from the above-named
spe. ies at first sight.

alpellum praeceps n. sp. PI. \ 111, fig. i ;,.

Valves fourteen, i by .1 velvety membrane; margins of valves nol everywhere to

distinguished. Carina with the umbo at the apex, simply and strongly bowed, with a flat
roof bordered by ridges \ chitinous interspace between the carina and the other valves.
Rostrum covered by membrane, narrow, elongate. Infra-median latus small, triangular. Carinal
latus with the umbo nol far from the base, al the tip of an obtuse angle formed by the longer
upper and shorter under half of the carinal margin.

This species is represented by one specimen only.

The capitulum is covered l>y a chitinous membrane which has a villous or velvety
appearance. Thé little hairs are especially conspicuous along the tree margin of the carina. As
shown in the figure the margins of the valves in consequence of the presence of this covering
can not everywhere be made out distinctly. The carina is separated from the Other valves by
a chitinous interspace which is broadest between the tergum and the carina. The capitulum is
rather steep [praeceps] and elongate, being twice as long or high as broad. The occludent
margin is slightly, the carinal margin strongly convex. The apex of the tergum and of the
whole capitulum is in consequence pointed and very slightly recurved.

The se ut urn has tin- ordinary shape ; the occludent margin is convex in its upper part.
The apex forms a very distinct recurved projection over the scutal margin of the tergum. The
scutum is about twice as long as broad.

The tergum is triangular. Its occludent margin is convex; its carinal margin nearly
straight. Where these two margins meet the pointed and feebly recurved apex is formed.

The carina is simply and rather strongly bowed with the umbo at the apex. Its roof
increases in width from the apex downwards, longitudinally hollowed out, being bordered by rather
prominent ridges. The sides of the carina have about the same width over the whole length.

The upper latus is trapeziform: the carinal margin runs parallel with the scutal one.
The umbo is at the apex, which is very slightly produced.

The rostrum is very narrow, covered by membrane, overlapped at each side l>y the
lateral margins of the rostral latera.

The rostral latus is quadrilateral, with the scutal or upper margin uplifted and
forming the continuation of the upper margin of the carinal latus. The length of the upper
margin is less than twice the length of the basal margin of the same valve.

The infra-median latus is very small, triangular, with the umbo at the apex.

The carinal latus is rather large and irregularly quadrilateral in shape. The upper

part of the carinal margin is slightly hollowed out, the under part slopes into the basal margin

and is convex. Where the two parts of the carinal margin meet the umbo is formed, which

very slightly projects beyond the line of the carina. The lateral and upper margins meet at a

blunt angle. The basal margin can hardly l>e distinguished as a special margin.

114

H5

The surface of the valves seems to be delicately striated; this striation, however, is
made nearly quite invisible by the chitinous membrane. It is slightly more distinct on the surface
of the carinal latus.

The p e du nel e is cylindrical, rather stout and short: about '/tth the length of the capi-
tulum. lts surface is invested with large scales, placed on five longitudinal rows, each row
composed of about 6 scales. The peduncle is also covered by membrane.

Size. The length of the specimen is 14,5 mm., that of its capitulum 11,7 mm.

It was taken by H M. S. "Siboga" at:

Stat. 159. August 16, 1899. Lat. o°59'.i S., Long. I29°48'.8 E. Depth 411 m. Bottom :
coarse sand.

Observation. This species in the shape of its capitulum and valves has a great
resemblance to Sc. striatum Gruvel, a species taken by the "Talisman", at a depth of 2995 m.
in the Atlantic not far from the Azores. But it differs from that species by its velvety membrane
and also by the form of the rostrum which is narrow and hardly visible in Sc. praeceps and
which (according to Gruvel) in Sc. striatum is: "tres net, triangulaire, allongé".

35. Scalpcllum incertum n. sp. PI. VIII, fig. 14 and \\a.

Valves fourteen, not covered by membrane, growth-ridges indistinct. Carina simply bowed,
with the umbo at the apex and with a flat roof bordered by ridges. Upper latus trapeziform
with the scutal margin nearly straight. Rostrum very small, hardly visible. Infra-median latus
triano-ular, very narrow, with the umbo at the apex. Umbo of the carinal latus very close to
the base of the carinal margin.

Of this species the "Siboga" collected two specimens.

The capitulum is flat, nearly twice as long as broad, with the apex pointed and
not recurved. The scutum is rather large though not very broad ; the rostral latus is much
narrower at the base than at its scutal margin. The carina is not strongly bowed, the lower
extremity reaches to near the base of the carinal latus. A chitinous interspace separates the
upper part of the carina from the tergum.

The scutum is quadrangular, about twice as long as broad; the basal and tergal
margins are of the same length, the occludent margin is strongly convex, the lateral margin
very feebly convex, nearly straight.

The tergum has a straight occludent margin, a straight scutal margin and an almost
straight carinal margin : the latter is slightly convex only in the lower part.

The carina is simply and not strongly bowed. The smaller and no doubt younger
specimen of the two has the carina less bowed than the larger (the one figured). The umbo
is at the apex; the roof is not very broad but bordered by distinct ridges ; the sides are rather
narrow and of nearly equal breadth over the whole length of the valve.

The upper latus is nearly trapeziform, not quite so as the angle formed by the
scutal and basal margins is truncated. The carinal margin is very short the scutal margin is
nearly straight, but slightly hollowed out. The umbo is at a little distance from the point where
the scutal and tergal margins meet.

"5

1 in

The rostrum is hardly visible, being covered on both sides by the margins of the
jtral margins of the two rostral latera do nol touch, io thal a narrow
strip of the small rostrum remains uncovered.

The rostral latus is quadrangular with the angle formed by the lateral and scutal
ins truncated. lts basal margin is much shorter than the scutal margin.

rhe infra-median latus is triangular, very narrow, with the umbo al the api
The api ■ not quite reach to the truncated angle of the upper latus.

The carinal lams is quadrangular, with the carinal margin onlj ver) ilightly Ik. Huw..!
<nu, with the upper margin straight .uu\ the basal margin slightly shorter than the lateral margin.
I umbo is very close tq the lower extremity of the carinal margin and does not pn
beyond the lin<- of the carina.

The peduncle is short, cylindrical but laterally compressed. The scales on the surfa
are- narrow, horizontally extended and ai some distance from one another. The) are arranged
in seven longitudinal rows: three on each side and one on the carinal of the pedui

Then about 8 scales in each longitudinal row in the largest specimen.

Size. The total length of the largest specimen was u mm., that of its capitulum 8 mm.

Both specimens were found attached to a brownish-coloured thread or fibre the nature
of which is unknown to me.

They w< llected by II.M.S. "Siboga" at:

St.it. t6i. August ij, 1899. Lat. i° io'-S S., Long. 130 9 I - Depth 798 m. Bottom: muddy
sand. 2 specimens.

Observation. This species has a great resemblance to various other species, for
example, to Sc. gracile n. sp. It differs from ii by the shape of the upper latus and of the
carinal latus. as also by the presence of a rudimentary rostrum of which no tracé could be found
in Sc. gracile. But tor the shape of the carinal latus it would be considered as belonging to
the same group of species ■ > - Sc. formosum, Sc. truncatum (which have a rostrum) and .is
Sc. tenue. Se. proclive and Sc. deforme (species without a rostrum).

36. Scalpellum fissum n. sp. PI. IX, fig. 1 and 2.

Valves thirteen. Tergum with the apex recurved. Carina simply and not strongly bowed
with the umbo at the apex, with narrow sides and with a laterally convex roof, bordered by
ridges. Upper latus with a longitudinal fissure. Infra-median latus wine-glass shaped. Carinal
latus with the umbo at the base.

The curious species is represented by four specimens, two large and two smaller ones.

The capitulum is rather flat and covered by a delicate membrane to which Radiola-
rians etc. adhere. Margins of the valves distinct. The qccludent margin convex, in the smaller
specimens even more strongly bowed than the carina! margin. Apex of the tergum recurved.
Valves of the lower whorl well-developed.

The se 11 turn is quadrilateral with the occludent margin convex. The tergal margin is
vex in the larger specimens; in the smaller it is nearly straight. The lateral margin is

n6

ii7

convex in the under part, where it forms a continuous curvature with the basal margin. It is
hollowed out in the lovver part where the apex of the upper latus borders upon it.

The terg urn is triangular. The occludent margin is convex, the carinal margin is
slightly hollowed out above the middle at the place where the apex of the carina touches it.
The surface of this valve appears to be larger in the smaller (shown in fig. 2) than in the
larger specimens as represented in fig. 1. Apex distinctly recurved.

The carina has a well-developed roof and narrow sides. The roof is not quite flat,
but laterally convex with narrow, rather flat borders. This valve is simply bowed, not very
strongly in the full-grown specimens, but much less so in the younger specimens, one of which
is represented in fig. 2. The carina of the latter is almost straight, making the convexity of
the occludent side of the capitulum much more prominent.

The upper latus is the most characteristic of the valves: it is almost divided into
two nearly equal halves by a split or fissure reaching from the basal margin to near the umbo
of the valve : the same fissure has about the same relative length on both sides of the four
specimens at my disposal. The apex of the valve is truncatecl, the umbo is at the extremity
of a triangular portion which rises slightly above the surface of the valve. The carinal margin
of the upper latus is short, the basal margin hollowed out, being divided into two parts, the
longer of the two having a very conspicuous curvature.

The rostral latus is quadrilateral with the lateral margin convex. The scutal margin
is slightly longer than the basal margin.

The infra-median latus is wine-glass shaped and has the umbo very near to the base.

The carinal latus is irregularly quadrangular. lts carinal margin is nearly straight, its
basal margin also straight. The lateral margin is convex and its upper margin is divided into two
parts, which meet together at an angle entering into the hollowed out basal margin of the upper
latus. Near its base the carinal margin has a little excrescence of nearly quadrangular form meeting
beneath the base of the carina with the same excrescence of the same valve on the other side.

The peduncle is cylindrical. In all four specimens it is distinctly curved, more strongly,
however, in the full-grown specimens than in the smaller. Its base of attachment is prolonged
at one end towards the occludent side of the capitulum and is covered by a large number of
scales arranged in fairly regular rows. The number of these rows is greater in the larger than
in the smaller specimens; while they are at some distance from one another in the smaller
specimens, they nearly touch in the full-grown animal. In consequence of the peduncle being
bent it is not easy to count the number of the longitudinal rows; in the full-grown specimen
their number, however, is not less than 14 to 15.

Si ze. The largest specimen had a capitulum of 9,2 mm. Its peduncle, if it could be
stretched quite straight, would measure about 7 mm. One of the smaller specimens had a total
length of 9,1 mm., its capitulum measuriiig 6,5 mm.

The specimens are attached to small sterns or sticks of different nature.

The study of the structure of the animal within the capitulum has yielded the
following results :

Mouth slightly bullate; crest of labrum with a row of very minute bead-like teeth.

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I IS

Palpi short, broad at the base, conical; ;i tuft "t' bristles at the apex, a few short hairs on
the interior margin.

Mandibles with three teeth and the inferior angle pectinated; tooth i and 2 twice
far ir« -in one another as 1 * *« »t 1 \ 2 and ;. distance between 3 and inferior angle still smaller.
Surface ol mandible covered with delicate hairs in groups of two or three on the part near
the toothed edge. Short hairs along the inferior margin.

Maxillae with a distinct notch slightly above the middle <>f the edge. Above the
notch the edge bears three strong and a smaller spine; beneath the notch the edge is straight
and is furnished with seven <>r eight spines of nearly equal si/e. Surface near the edge covered
>vith hairs; superior margin furnished with a few hairs in the neighbourhood of the first spine.
interior margin with a row of numerous hairs.

• 'uter maxillae have the inner surface rounded with numerous bristles, which can
hardh be said to be divided into two different groups; opening communicating with the body-
cavity at the eml of a very long and flattened projection, cut off transversely at the extremity.

Cirri. First pair at a little distance from the second, short, with unequal rami,
shorter ramus flat with eight segments which are oblong in transverse direction; segments much
flattened towards the inner margin where each is furnished with a row of five or six strong
spines ; longer ramus with 9 segments, of a more cylindrical shape, furnished with a row of five
to six spines along the outer as well as along the inner margin. Both rami thickly clothed
with longer hairs.

Second cirrus shorter than the following. Anterior ramus with seventeen, posterior
with eighteen segments. First segment long, segments 2 — 8 nearly <|iiadrilateral, segments 9 and
following ones becoming more and more elongate, last segments very long and narrow. Each
segment lias about four pairs of bristles along the anterior margin, a few hairs along the
posterior mar- in and also one or two longer hairs at the extremity of each segment.

Sixth cirrus rather long with about twenty-four segments in each ramus. Basal segment
long, cylindrical, segments 2 — 6 quadrilateral, 7 and following ones growing gradually longer
and more slender. As a rule the segments are furnished with four pairs of spines along the
anterior margin and a single spine (or no spine) at the posterior margin near the extremity.

Caudal appendages have six segments. They are very slender, and reach with their
last segment only slightly beyond the pedicel of the 6lh cirrus. Very long and delicate hairs are
planted at the extremity of the second to sixth segments. The extremity of the last segment is
furnished with half a dozen hairs. two of which are longer than twice the length of the segment.

No penis.

Male. I found two males on the one, three on the other side of . one of the females.
'1 hey are attached to the inner side of the scutum, near the occludent margin, in a duplicature
of the sac or mantle, slightly in front of the adductor muscle. They have the ordinary long
oval shape and show no tracé of valves. Their size is about 0,84 X 0,42 mm. Their surface is
clothed with very short hairs or spines, which stand alone or in groups of two or three without
forming regular rows. Slightly longer hairs form a little tuft on each side of the opening giving
entrance to the interior of the sac. 'The prehensile antennae have the ordinary shape: a longer

118

ii9

cylindrical segment and a shorter conical one; they are attached about the middle of the length
and not at or near the extremity of the male. The musculature of the sac is strongly developed,
the muscles forming parallel hoops along the inner side of the transparent sac. The male genital
apparatus is well-developed, the animals being in ripe or nearly ripe condition. The testiculum
is heart-shaped and communicates with an oval receptaculum seminis, quite filled up with the
thread-like spermatozoa.

This species was collected by H. M. S. "Siboga" at two stations, viz. :

Stat. 137. August 3, 1899. Lat. o°23'.8N., Long. I27°29'E. Depth 472 m. Bottom: fine dark

muddy sand. One large and two smaller specimens.
Stat. 212. September 26, 1899. Lat. 5°54'-5S., Long. I20°I9'.2E. Depth 462 m. Bottom: fine

grey and green mud. One larger specimen.

Observation. This is without doubt a very characteristic species. The curious shape
and structure of the upper latus entitles one fully to say so. The change in shape of the
capitulum and of the carina and tergum especially, which appears to take place during growth
is, I think, also worthy of mention. I give two figures therefore : one of the largest and one
of a younger specimen.

$j. Scalpellum caudiduui n. sp. PI. IX, fig. 3 and 3^.

Valves fourteen, not covered by membrane. Carina simply bowed with the umbo at the
apex-, its roof flat, very broad, bordered by ridges. L^pper latus pentagonal, apex not produced.
Rostrum small, circular. Infra-median latus large with the umbo at the base. Carinal latus
triangular, with the umbo at the angle formed by the carinal and basal margins.

This small species is represented by one specimen only. In many regards it resembles
Sc. poculum (pag. 100) and I think it best merely to point out the differences between these
two species.

The lateral and basal margins of the scutum and the short margin separating this
valve from the infra-median latus describe together one continuous arch, which is not the case
in Sc. poculum.

The occludent margin of the tergum is distinctly convex, its apex is recurved.

The carina has the lower part of the roof broader than in Sc. poculum.

The apex of the upper latus is not produced, not so distinctly produced as in the
other species.

The rostrum is hardly visible. It is a very small circular plate fitting exactly between
the upper rostral extremities of the rostral latera.

The rostral latus has the rostral margin considerably shorter than the lateral margin so
that the basal and scutal margins are not nearly parallel (as in Sc. poculum) but distinctly diverging.

The infra median latus of the present species has a more compressed form.

The carinal latus is large and has an irregular triangular shape, the lateral and

upper margins sloping into one another insensibly and the carinal margin forming one straight

line. The umbo is seated quite at the base where the carinal and basal margins meet at a

sharp angle.

119

I 2< I

the peduncle are very distinct, al .ome distance from one another and
[itudinal rows. The length of the peduncle is about half the length of the capitulum.
total length of the animal is 7,8 mm., that of the capitulum 5,5 mm.
took the specimen at

Lal ; \.. I ! E. Depth 204 m. Bottom: hard

il s. nul.

/////// 11. sp. PI. IX, fig. 4.

\ .'..- thirteen covered with ;i delicate brownish membrane. Carina with the umbo at
the apex and with a flat roof bordered by ridges. Lateral margin of the scutum with a deep

ir incision near the upper extremity for the reception <>i 1 1 1 « - apex <>t the upper latus.
Valves "f tin- lower whorl large. Infra-median latus wine-glass shaped with the umbo near the
Carinal latus quadrilateral with the umbo near the base.

This curious di cies is represented liy a single specimen only.

The capitulum is rather flat, little more than twice as long as broad, having the
carinal margin slightly mort- convex than the occludent margin. The apex of the tergum is
pointed and a little recurved. TIn- surface is of a browny yellowish colour; scratching it with
a needie a very delicate skin or membrane loosens in little flocks from the surface. The ridges
«>f growth are very distinct on most of the valves; parallel furrows are visible <>n the scutum,
on tin- upper latus and also on the carinal latus near the- base. The valves are separated from
each other l>v narrow, hut distinct chitinous interspaces; that between the tergum and tin- upper
halt" of th<- carina being much broader than tin- others.

The scutum has a very characteristic shape. lts occludent margin is convex; its tergal
margin hollowed out near the apex and convex towards the other extremity. The lateral and
basal margins slope into one another quite insensibly; near the upper extremity the lateral
margin shows a very characteristic incision in which the apex oi the upper latus hts exactly.

The tergum is triangular. lts occludent margin is convex, its carinal margin slightly
hollowed out in the upper, slightly convex in the lower part. The apex is not strongly, yet
distinctly recurved.

The carina has a tlat roof which is bordered by ridges, but does not increase in width
very strongly from the apex downwards. The sides of the carina are well-developed over its
whole length. they increase only slightly in width from the base to the tij» of the valve.

The upper latus is pentagonal with the sides of very unequal length. The carinal
and the basal margin along the infra-median latus are the shortest, the convex tergal margin
which is slightly hollowed out in the middle is the longest. The lateral margin is hollowed out
and a little longer than the basal margin separating this valve from the carinal latus. The umbo
is at the apex which may be called beaked.

The rostral latus is quadrilateral; the upper and basal margins are of about equal
th. the rostral margin is slightly convex, the lateral margin distinctly convex.

The infra-median latus has the shape of a wine-glass and is relatively large. Both

120

I 2 I

lateral margins are distinctly hollowed out. The umbo is near the base, beneath the centrum
of the triangular part which represents the foot of the wine-glass.

The carinal latus is large and has an irregular quadrilateral shape. The carinal
margin is nearly straight, the umbo of the valve is at the angle where the carinal and basal
margins meet. The upper and lateral margins meet at a very blunt ano-le.

The p e d u n c 1 e is short and shows eight not very distinct, longitudinal rows of scales :
three on both sides, one along the carinal and one along the rostral side of the peduncle.
The scales are much larger and much more distinct near the upper extremity of the peduncle.

Si ze. The only specimen representing this species has a total length of 19 mm. the
length of the capitulum being 14,8 mm. It was found attached to a bundie of brownish threads
or hairs, the nature of which is unknown to me. It was taken by H. M. S. "Siboga" at:

Stat. 295. January 24, 1900. Lat. io°35'.6S., Long. ï24°ii'.jE. Depth 2050 m. Bottom: fine
grey mud.

Observation. This species is at once recognisable by the form of its scutum and that
of its infra-median latus and carinal latus. It belongs to the same group of species as Sc. fissum,
Sc. candidum and Sc. inccriiim, but may be very easily distinguished from each of these species.

Genus Pollicipes Leach

In the Malay Archipelago this genus is represented by one species only1: P. mitella (Lin.).
Like the other species, P. mitella lives near the coast in shallow water, attached to rocks,
stones or shells.

Darwin described six species of this genus in 1851 and since his Monograph appeared
the number has increased by one species only: P. Darwini Hutton from New Zealand. It is
the oldest known fossil genus of Lepadids and it must have been represented by very numerous
species in former geological periods : Darwin enumerates 22 fossil species in his Monograph
on the fossil Lepadidae of Great Britain.

The above-named species was collected by H. M. S. "Siboga" on two different occasions.

1. Pollicipes mitella Lin.

This is a very characteristic species and Darwin has given an excellent description of it.

Rumphius knew it already as an inhabitant of the Malay Archipelago and also Seba.
It occurs as far north as Japan, as far west and south as Madagascar, as far east as Hawaii
(autor. Gruvel).

Concerning the bathymetrical distribution of this species not much is known : it is
generally considered to be a shallow-water species or even a littoral form. In my Report on
the Cirripedia of the "Challenger" Expedition I said that it was not on record that any one
of the species of Pollicipes occurs at a depth of even 10 fathoms, and so far as I know this
still holds good.

1 Gruvkl, Monographie p. iS, says that P. clegans Lesson occurs at Java, but he does not name the authoiity who obsevved
that species there — I hardly believe he is right

SIPOGA- EXPEDITIE XXXI a.

16

l 2 2

During tli*- cruise "i 11 M. S ■Siboga" specimens o\ this species were collected on two

station gi: Madura Bay in the southern part of Molo Straitj on the shore. About
\l of 1

\ B. As mentioned already p. 47 specimens <>f Ibla Cumingi Darwin were found attached
ti. several specimens of P. mitella at Station 51.

is Lithotrya Sowerby

1 >t" this genus si\ species were known to Darwin in 1851 and only «nu- new spei
(L. / lias been added to this number in the 55 years since then. They are found

■ ,1 in cavities, in calcareous rocks, shells, or corals and have been observed "generally"
witliin the tropics. All tin- species occur only in shallow water.

In the Malay Archipelago and in Australian waters, \, perhaps 5, ol the known species
been observed: /.. cauta Darwin, New South Wales, Australia; L. nicobarica Rhdt., Timor;
/. truncata Quoy et Gaimard, Philippines; L.pacifica Borradaile, Funafuti. [Perhaps /.. rhodiopus
f. 1-".. Gray, the habitat of which was unknown t<> Darwin, belongs to the same region also;
tin- Copenhagen Museum possesses specimens labelled /.. rhodiopus J. E. Gray, Funafuti; they
are specimens purchased from the Museum Godefroy.

ll.M.S. "Siboga" met with specimens of this genus <>n five different occasions; tour
different species are represented in this collection.

1 . Lithotrya nicobarica Rhdt.

Reinhardt (1850) has given the description of this species founded 011 specimens trom
the Nicobar Islands. Darwin i 1851 1 when giving the description of this species in his Mono^raph
had Ki inhardt's paper at his disposal, luit he could nol compare the typical specimens used
by Reinhardt. The specimens which Darwin identified with R.'s species were trom Timor.

Through the courtesy of the Director, Prof. Jungersen, and the Keeper of the collection
-f Crustacea, Dr. Meinert, of the Copenhagen Museum. I got free access to the specimens of
this species which are to be found in that Museum. They are — accordiiiL; to the label — from
Pulo Milu, Galatea. As Galatea Bay is the name of a Baj "f the [sland Sambelong Great
Nicobar), and as they are the only specimens of this species in the Museum, the probability
that they are the original specimens of Reinhardt seems great1. They correspond with Darwin's
description and figures in all essential regards.

il forms collected during the cruise of II. M. S. "Siboga" belong doubtless to this

ej are from two different Stations: from the reefs near Lucipara and from the

of the Island of Kur, West of the Kei Islands. At both places, however, together

1 '1 lu -^c hart not been put a>iilo a^ type-specimen iw tlic custom with specimens which have served Oir the institution

• Dr. Mkineri could nol say «iili absolute cettainty, that they were Rbinharut's types.

with, I might say, typical specimens of L. nicoöarica, other specimens of a form or species of
Lithotrya were collected, which after careful study I feel inclined to consider as different
from Reinhardt's L. nicoöarica. I shall describe the other form as a new species and call it
Lithotrya conica • as the comparison of the different specimens with one another and with
Darwin's description brought to light that more or less interesting differences occur even between
the specimens which doubtless belong to the original species of Reinhardt, I think it useful to
enter into some detail on that species first of all.

With regard to the valves of L. nicoöarica the following may be pointed out:

The scut u m has the tergal margin either straight or slightly sinuous, in which case
the upper part is hollowed out.

The carina has a well-developed central, internal ridge which extends over the upper
half of the valve. The inner growing surface is in most specimens but very indistinctly pentagonal.

The rostrum is different in size in the different specimens, the number of zones
preserved varying in the 18 specimens I was able to observe from 2 — 7. This number was 2 in
three specimens, 3 in ten, 5 in three, 6 in one and 7 in one. The number of the subjacent
scales of the peduncle, which the rostrum equals in width, varied from 4 to 7 : it was 4 in four
specimens, 5 in five, 6 in seven and 7 in two. In one of the specimens from Pulo Milu, Galatea,
which I was able to study more carefully, the number of distinct zones was 3 and the number
of scales of the peduncle which the rostrum equalled was 7. [In the figure of this species
Darwin reproduced after Reinhardt a much greater number of zones is indicated.]

The la ter a which according to Darwin are unusually large in this species vary greatly
in the different specimens. Their general shape is as described by Darwin : triangular, elongated
transversely with the carinal angle a rectangle-, but they are much broader in some, narrower
in other specimens. I compared the length of this valve with that of the carina and I thus
found that it can be less than half as long as that valve and also nearly as long as it : in a
specimen the length of the carina in which was 13 mm. the latus measured 11 mm., and its
length was 6 mm. in another specimen, the carina of which was 7 mm. long. The number of
zones of growth preserved in the specimens I investigated also differed greatly: on 18 specimens
this number was once 8, twice 7, three times 5, four times 4 and six times 3. In the two
remaining specimens the zones of the little valves were quite covered with chalk and could in
consequence not be distinguished. The latera as a rule equal in width the seven subjacent scales
of the peduncle; in some of the specimens this number, however, is six or five and in one
specimen four of the scales equalled the width of this valve.

With regard to the peduncle the only difference from Darwin's description I noticed
was that the shape of the upper scales was more irregular.

With regard to the body of the animal I may point out the following :
The labrum has a row of blunt teeth; its palpi have their ends rather more rounded
than truncated.

The mandibles have the distance between the tips of the first and second teeth 7,
taking the distance between the tip of the second tooth and the inferior angle as 9.

The maxillae sometimes have the notch beneath the large upper and two smaller

'- 1

spines distinct, sometimes it is hardly visible. In m> case have 1 observed two large upper

spines. In the notch, <>r il" it is absent at the place it occupies in other maxillae, three or tour

short and delicate hairs are planted. Nexl follows a slightly protuberant par! with 5 <>r <>

and then a second smaller notch. Hien about 8 pairs of spines and linally th<'

dub prominent inferior angle with a brush of rather short spin<

The outer maxillae have a smal! but distinct notch between the upper and lower
iup of sjiiii'

Of the cirri the lirst pair is short; the general shape of the segments of this pair
is narrow ar the base and broader at the other extremity. The anterior ramus has 8 segments
on the right side and 12 on the left, the posterior 1 2 and 13 respectively. The segments ar<:
thickly paved with bristles, which are themselves coarsely and doubly serrated.

The second cirrus has \- and 20 segments; the 8 basal segments of the anterior
ramus are highly protuberant and thickly clothed with spines; the posterior ramus has only 5
these basal segments and 15 upper segments with the usual structure.

The third cirrus has ^j and 24 segments: six and live of these are highly protuberant
and thickly clothed with spines.

The fourth cirrus has 2} segments in both rami and the front of the basal segments
not protuberant, as is the case in the three preceding pairs.

The fifth cirrus has 25 — 26, the sixth 23 — 26 segments.

The caudal appendages are long, reaching as far as the extremity of the eighth
ment of the anterior ramus of the sixth cirrus. The number of segments was 23.
The penis is short, thick at the base, distinctly ringed.
During the cruise of H.M. S. "Siboga" this species was observed at the following places:

Station 221, ■. Reef near Lucipara islands; 8 — 10 November 1899. 17 specimens.
Station 250: Reef hear Kur island ito the W. of the Kei islands), December 6 — 7, 1899.
1 specimen.

2. Lithotrya conica n. sp. PI. IX, fig. 10 — 12.

Scutum large, indistinctly beaked and slightly overlapping the tergum ; tergum much
smaller than the scutum, their tips coming close together; carina triangular. strongly bowed
laterally, feebly bowed vertically; rostrum small, as wide as four (or less) of the subjacent scales;
latus having the shape of a parallelogram, its base as wide as four of the subjacent scales.

Palpi with the tips rounded, conical ; mandibles with not very numerous pectinations
between the teeth : maxillae with the inferior angle hardly prominent; outer maxillae without
notch between upper and lower group of spines.

The capitulum as a whole lias a conical shape, its rostral and carinal margins being
both nearly equally curved. The tip of the scutum reaches as far or slightly farther than that
of tlv tergum, the tip of the carina not extending so high up.

The scutum (PI. IX. fig. 11./ is considerably larger than the tergum, its occludent
ni is bowed and long, its tergal margin is hollowed out, or (in the largest specimen)

'-1

125

straight. It is indistinctly beaked : the tip being rounded off as a rule. It overlaps the tergum
only very slightly.

The tergum (fig. i i B) has an irregular triangular shape. It is divided by a ridge
running from the apex to the basal-scutal angle into two parts: a larger triangular part and a
smaller one of an irregular shape. The latter part is to a small extent overlapped by the
scutum. lts free margin (the scutal margin) is bowed in the upper half and slightly hollowed
out in the lower half.

The carina (fig. 11 C) has about the same size as the tergum, its shape is triangular
and it is bowed in a lateral as well as in a vertical direction : the inner surface is concave in
consequence. The upper free portion has a very slight central ridge. The inner growing portion
is indistinctly pentagonal.

Scutum, tergum and carina have numerous and very distinctly projecting rims on which
numerous and very small teeth are visible.

The rostrum is small and is composed of only two or three zones of growth. The
number of subjacent scales of the peduncle, which the rostrum equals in width, is three, in
one specimen four.

The iatus is also small. It has the shape of a parallelogram and shows only 3 or 4
zones of growth. Along its base there are at most four scales of the peduncle.

The peduncle shows a distinctly swollen ring covered by about six horizontal rows
of scales immediately beneath the capitulum. The first, second and third row have the scales
of an irregular transversely elongated shape, the inferior margin being crenated. The scales of
the three following rows are much smaller (PI. IX, fig. 1 2). A few rows of much smaller scales
of an irregularly rounded form are seen under this swollen ring and then follows the main part
of the peduncle which shows no scales on the surface and is indistinctly ringed. The width of
the peduncle diminishes considerably from the capitulum downwards.

The size of the largest specimen was: length 46 mm., 34 mm. being accounted by for
the peduncle; greatest breadth of the capitulum at its base: 13 mm., smallest breadth : 7 mm.
Most specimens are, however, considerably smaller.

The body of the animal differs from that of L. nicobarica in the following regards :

The labrum has about twelve small blunt teeth on its central and about 15 on each
of the lateral parts. Palpi short conical, with the tips rounded.

The mandibles have less numerous pectinations between the first and the second, as
also between the second and third teeth, viz. : 1 2 and 7 to 8 respectively.

The maxi 11a e have a notch, two spines are inserted above it, half a dozen delicate
ones in the notch and numerous pairs of spines beneath it. The inferior angle can hardly be
said to be prominent.

The outer maxillae have the spines continuous over the inner and outer margin.

The cirri correspond in general with those of L. nicobarica, but the number of segments
is not inconsiderably smaller :

The left cirrus of the first pair has 9 and 1 1 segments in the slightly unequal rami ;
the cirrus of the right side has 1 1 and 1 2 segments in the same specimen.

125

IJ''

The second pair has 15 and 18 segments,

tlic third pair 1 7 and gments,

the fourth pair 20 and 2 [ments,

the ii 1 1 li pan- 2 1 and 2 1 segments,

the si\th pair 22 and 'ments.

rhe surface of the segments of the \ cirrus is smooth <>r nearlj -■<. the minute

which make the surface hirsute in /.. nüoóarüa, are wanting in /.. conica.

[*he can «lal appendages contain [8 segments in tin- specimen in which the sixth

rirrns had 22 segments in each ramus.

[*he p<nis in much like that "i /. nüoóarüa.

This species h,i> collected at the following Stations during the expedition of H.M.S. "Siboga

near Lucipara [slands; 8 [O November [899. 8 specimens.
■ near Kur Island ito the West of the Kei [slands), Decembei 6 7 1899.
cimens.

General Rem ark. Ai both places where specimens of /.. nüoóarüa were collected,

mens ut' /.. conica were also found. lt cannot be made out, however, with the aid ol the

rved material, whether the specimens were really found at exactly the same place and

lived under absolutely similar circumstances, or not. The specimens of L. conica are smaller

than most of /.. nüoóarüa; some of the latter, however, are as small as most of the L. conica,

yet show the differences in the shape <>l the capitulum and of the valves, which 1 think are

striking. There is therefore no reason lor me to admit that the one form represents

younger, the other older specimens of the same species. On the other hand I would by no

means be surprised if future investigations show that the two forms really belong together in

some way or other.

;. Lithotrya pacifica Borradaile. PI. IX. figs 13, 13a and 14.

BORRAUAILE, I.. A., On some Crustaceans from the South Pacific. Part \'. Proceedings of

the Zool. Soc of London. 1900, p. 70.S, l'l. LI. figs 3, 3a.

On the east coast of Lombok two specimens of a Lithotrya were collected which 1
think belong t" the species described lor the first time by Borradaile from specimens from the
outer reef of Funafuti.

The specimens from Lombok differ in several more or less important points from the
diagnosis given by Borradaile. I consider it useful therefore to give a figure of the largest of the
Lombok specimens (fig. 1;,) and to point out the most essential differences in a short description.

The scutum is triangular, considerably shorter than the tergum, overlapping the latter
valve not a little; its external surface is very distinctly ridged.

The tergum is somewhat narrow, more elongate-rhomboidal than triangular; its basal

portion is overlapped on the one side by the scutum. on the other by the latus; externally the

part not overlapped b) scutum and latus shows a prominent longitudinal ridge with the /ones

of growth running transversely and nearly straight. The latus is long and stout, its length

the length of the tergum, its extremitj being nearly on the same level with that of the

1 -">

i 27

scutum. It consists of about 8 divisions, separated by prominent transverse ridges, each of which
is curved with the curvature away from the extremity. The base of the latus corresponds vvith
4 (indistinctly 5) of the underlying scales.

The c a r i n a is very long and rather narrow, curved longitudinally and strongly bowed
laterally, hence very distinctly concave over its whole length. lts extremity stands off and
reaches higher up than that of the tergum. The middle row of knobs described by Borradailk
very distinct.

The rostrum composed of 4 (in the smaller specimen 3) divisions, small and narrow,
its base bordered by a row of five scales (fig. 13^).

The peduncle is rather thick, swollen and not very long: as long as the capitulum
in the smaller specimen, about twice the length of the tergum in the larger specimen. The
upper scales (fig. 14) are broad and distinctly crenated; those of the second whorl are half or
one third the size of those of the upper whorl and are so placed that one is exactly under
the centre of an upper scale and another between two of these. The scales of the third and
fourth whorls are much smaller ancl not placed so regularly ; then follow still smaller ones,
rounded calcareous beads invisible to the naked eye, which are distributed over the whole
surface of the peduncle.

The colour of the capitulum and the peduncle is a dark, beautiful brown, the tip of
the tergum and the rows of scales immediately underneath the capitulum being white.

Size. The length of the largest specimen, including the peduncle, is 25 mm., the length
of the carina in the same specimen being 9 mm.

The two specimens were collected at Labuan Pandan, which is on the east coast of the
island of Lombok.

Observations. Perhaps Darwin's L. catita comes nearest to this species ■ the
specimen Darwin made use of for his description was only 5 mm. in length including the
peduncle, and may not have been fullgrown.

The smaller specimen of the two collected by H. M. S. "Siboga" has the tips of some
of the valves (tergum and carina) broken off and the space between the slightly distended
valves is filled up with dirt; a small specimen of Ibla (? Cumingi Darwin) was found attached
to the inner side of one of the valves.

4. Lithotrya truncata (Quoy et Gaimard).

Of this curious species, which was founded for specimens from the Friendly Archipelago,
and was known to Darwin from specimens from the Philippine Archipelago, two specimens
were collected during the cruise of the "Siboga" at:

Stat. 60. 27 — 28 April 1899. Haingsisi, Samau Island, Timor: Shore exploration.

They are small specimens: the largest of the two measures (capitulum and peduncle
together) about 1 1 mm. A very small specimen of what I believe to be an Alepas (perhaps
identical. with the Alepas lithotryae I found attached to L. nicobarica) occupies the corner
between the tergum and the carina where the rudimentary latus is to be looked for.

127

PLATES

PLATE I

i ir i nut ii»i Hoek.

i Group "i animals; magnified 3,25 diameti

l ; lastna dubium 11. sp.

2. Animal, lateral view; magnified 3,6 diameters,
irina, lateral view; magnified 11 diameters.
1. Carina, lower pari, interna] view. magnified 11 diamei

4. Maxilla; magnified 134 diameti

5 -8. Poecilastna excavatutn n. sp.

5. Animal, lateral view; magnified 4 diameters.
Fig. 6. Tergumj magnified ro diameters.

I ig. 7. Carina, lateral view; magnified 8 diameters.

i.Carina, lower part. external view; magnified 8 diameters.
Fig. 8. Caudal appem nified 36 diameters.

1 . 9 — 10. Poecilastna excavatutn, varietas.

vinmal. lateral \iew; magnified 5,3 diameters.
I . 10. Apex cf the scutum with the division of the tergum; magnified 36 diamei

Poecilastna obliquum n. sp.
Fig. il. Animal seen from the right side; magnified 3,6 diameters.

. ij. Animal from the left side ; magnified 3,6 diameters.
I ig. [3. Scutum of the left side. interval view; magnified 3,6 diameters.
1 ;. rergum of the right side, external view; magnified 36 diamet
irina, lateral view; magnified 3,6 diameters.
I i . 15^. Carina, interna! view; magnified 3,6 diamet
Fig. 16. Labrum, seen from above; magnified 36 diameters.
I ig. [6/i.Teeth of the labrum; magnified 180 diameters.
I . 17. Mandible; magnified 52,5 diameters.
is. Maxilla; magnified 52,5 diamat

< luter maxilla; magnified 52,5 diameters.
. 20. Left cirrus of the fifth pair; magnified 36 diameters.
1 .21. Right cirrus of the fifth pair; magnified 36 diameters.
I 22. Caudal appendages; magnified 36 diamet'

Siboga-Exf editie. XXXI. P. I'. C. Hoek, Cirripedia.

1

_ i

x 3;

2

x 3.6

5

X 4

■

y#">

10

X 36

3a

6

X 10

11

X 3|

12

X 3|

13

X3i

15

15 a

X 3|

20
X 36

16 a

X 180

7a

14
X 36

0

16

X 36

22

X 36

21
X 36

18

X 52.5

19

X 52. 5

17
X 52.5

P. P. C. Hoek del.

PORCILASMA.

Fa. P. \V. M. Trap. impr

PLATE II

i 7. Dich 1. sp.

1. Animal, lateral view; one of the large, hairy specimens collected at Station 258, I ual
Anchorag» . Kei [slands; magnified 1 1 diameters.

2. Animal, lateral view, made transparent; magnified 11 diameters.
2a. Very young specimen; magnified 11 diamet'

Scutum and tergum of a young specimen; magnified 28 diameters.
\a and 4". Scutum and tergum of a full-grown specimen, magnified 28 diametei
5. Carina, lateral view, of a full-grown specimen; magnified 11 diameter ,
irina, lower part, internal view; magnified 11 diameters.
Mandible; magnified 180 diameters.
7. Maxilla; magnified t8o diameters.

I 1 ;. Dichelaspis Tydemani n. sp.

s. Animal, lateral view, made transparent; magnified 34 diameters.

9. Scutum; magnified 63 diameter-.

io. rergum; magnified 63 diameters.

il. Carina, lower part, internal view; m 63 diameters.

ij. Mandible; magnified 356 diameters.

13. Maxilla; magnified 356 diameters.

I . Dichelaspis orthogonia Darwin.

. 14. Animal, lateral view; magnified 10,3 diameters.
Fig. [5. <i. Scutum: b. Tergum; c. ( irina; magnified 10,5 diameters.

Termination of the carina, external view; magnified :?* diamei
17. Maxilla, magnified 254 diameters.
Fig. [8. A specimen of the same species from another Station; magnified 11 diameters.

Siboga-Expeditie. XXXI. P. P. C. Hoek, Cirripedia.

//

1

x n

^,

6

X 180

.' ■■

»

^ r

ii

X S3

10

I

2

>/

-^

3%

2a

x 11

7
X180

3a

_

'

17
X 2S6

8
X 34

-.

'"" -

5

14
HO 3

16

X 28

12

13

15

X 10;

%d

18
xu

P. P. C. Hoek del.

DICHKI.ASl'IS.

Fa. P. W. M. Trap, impr.

PLATE III

*

i. i . /. [2? and lob. Dichelaspis orthogonia Darwin.

i. ,i. Scutum; />. Tergumj c. Carina; magnified 19 diameters.
Fig. i.l. Very young specimen; magnified 36 dianieters.
I iB. Young specimen; magnified y> diameters.

ii ma trom the interior; magnified 15 diameters.

I - 7- Dichelaspis Weberi n. sp.

Animal, lateral view; magnified 63/a diameters.

,/. Scutum; b. Tergum; c. Carina; magnified 10 diameters.

1 arina, external view of the disc; magnified 10 diameters.

Mandible; magnified 134 diameters.

Maxilla; magnified 134 diameters.

(»uter maxilla; magnified 52 diamei

1;. Dichelaspis Versluysi n. sp.

li'. S. Animal. lateral view; magnified 11 diameters.

9. a. Scutum; 6. Tergum; c. Carina; magnified 15 diameters,
icw. Carina from the interior; magnified 15 diameti
. 11. ii. Mandible, magnified 63 diameters; b. inferior angle of the
mandible of the right side; c. the same of the mandible of
the left side. 11/' and c magnified 160 diameters.
ij. Maxilla; magnified 180 diameters.
Fig. 13. Caudal appendage; magnified 63 diameter-.

Fig. 14. Dichelaspis Versluysi, varietas.

Fig. 14. Animal, lateral view; magnified 11 diameters.

2,

3-

Fig.

4-

1 ig-

5-

6.

7-

Sil>oxa-E\/>c,/i/ir. XXXI. I' ?. C. Hoek, Cirripedia.

///

i

X 19

1B
X 36

2

X6#

^r

IA
X 36

7
X 52

6

X 134

i
X 10

10

X 15

a 1)

9

X 15

11a
X 63

14
x u

11
X 160

12
X134

P. P. C. Hoek .lel.

DICHKI.ASPIS.

Fa. P. \V. M. Trap, impr.

PLATE IV

1 'S"

l .

■»

Fig.

v

1

4-

5-

Fig.

6.

7-

8.

\fegalasma lineatum n. sp.
l ï. Anima), lateral view . magnified 5 diameters.

Same, a^ seen from the carinal sidej magnified 5 diameters.
Interior of </. scutum, 6 tergum and 1 carina; magnified 5 diamet
Carina, dorsal view; magnified 5 diameters.
Labruin ; magnified 52,5 diameters.
Mandible; magnified 52,5 diameters.
Maxilla; magnified 52,5 diameters.

Pedicels of cirri of the sixth pair with the caudal appendages (ca.);
magnified 52,5 diameters.

9—12. Alt-pas tnorula n. sp.

Fig. 9. Animal, lateral view; magnified 3,4 diameters.
Fig. to. Labrum; magnified 52,5 diameters.
Fig. 11. Mandible. magnified 52,5 diameters.

. na. Inferior angle of the same; magnified 180 diameters.
12. Maxilla; magnified 52,5 diameters.

1 3 — 1 6. Alrpas intermedia n. sp.

Fig. 13. Animal, lateral view; magnified 3,6 diameters.
I . [4. Labrum; magnified 52,5 diameters.
Fig. 15. Mandible; magnified 52,5 diameters.
Fig. 16. Maxilla; magnified 52,5 diameters.

17 — 18. Alepas ovalts n. sp.

Fig. 17. Animal, lateral view; magnified 3,3 diameters.

iS. Animal, seen from the rostral side; magnified 4 diameters.

Fig.

magnified 3,3 diameters.

19. Alt pas tenuis n. sp.

1 . [9. Animal, lateral view

20 — 22. Ibla Sibogae n. sp.

I ;. 20. Animal, lateral view after the right half of the capitulum and the whole

body has been taken away. Two little maks are seen in the mantle-

ity; magnified 3 diameters.

Fig. zi. Interior of the scutum A and the tergum B\ magnified 18 diameters.

Fig. 22. Labrum with the mandible of the right side: magnified 52,5 diameters.

22a. (nferioi angli of the mandible; magnified 254 diameters.

Si Iw^a Expeditie. XXXI. P. P. C. Hork, Cirripedia.

TV

3 X

X 5

5

* bib

6

>. 52 6

11
X 52 5

9
X 3.4

.<*

10
X 52.5 \

14
X52.5

11a
X 180

8

X S2.5

12

X 52.1

13
X 3 S

.

22 a

X 254

15

X52.S

16

XS2 5

r
17

18
X 4

: IS

X 3.3

20

X 3

22

X 525

21

X 18

P. P. C Hoek del

MF.GALASMA — AI.KPAS -- IP.LA.

Ka. P. \V. M. Trap. impr.

PLATE V

n. sp.

i. Maxilla; magnifïed [80 diameters.

2. Second maxilla; magnifïed 78 diameters.

;. Male. magnifïed 36 diameters.

;- 1 ronl part of the same male; magnifïed yS diameters.

-. Front part of another male, seen from the dorsal side; magnifïed 1S0 diameters.

6. Labrum with palp and mandible /// situ, of a male; magnifïed 180 diameters.

7. Mandible <>f a male; magnifïed 440 diameters.
I ... S. Maxilla of a male; magnifïed 440 diameters.

'i 11. Scalpellum pollicipedoicUs n. sp.

Amm.d seen from the left side; magnifïed 11 diameters.
Fig. 1 . Anoth nnen; a. the two additional valves of the lowcr whorl; magnifïed

I 1 diameters.
i :. 1 omplemental male; a, antennae, c, carina, r, rostrum, se, scutum, t, tergum, /.part
of the tergum, corresponding with the primary valve; magnifïed 1S0 diameters.
\lpellum artes n. sp.

ij. Animal. lateral view; magnifïed 5,6 diameters.

I 1 ; S alpellum rostratum Darwin.

[3. (.'omplemental male; magnifïed 52,5 diameters.

üpellum Peroni (Gray).

14. Animal, lateral view; magnifïed 2,8 diameters.
. 14.I, Sub-carina; 14/.'. Rostrum.

' 5. üpellum uncus n. sp.

Fig. 15. Animal, lateral view; magnifïed 5,6 diameter-.

Siboga- Expeditie. XXXI. P. P. C. IIokk, Cirripedia.

j.

A

''™

13

X52.5

P. P. C. Ilnek del.

IBLA — SCAI.PI'.l.LUM.

Pa. I'. w. m. '1

r;i]>. impr.

PLATE VI

i. Scalpellum Stearnst Pilsbry.

i. Anima] seen from the left sidej natura] size.

j, Scalpellum Stearnst Pilsbry, var. robusta n. var.

I ig. 2. Anima! seen From the left side (Station 5); natural size.

Fig. 3. Idem (Station 254); magnified 1,1 diameters.

Scalpellum Stearnst Pilsbry, var. gemina n. var.
Fig. 4. Two specimens attached to a sponge (Station 74); natural size.
Fig. 5. Valves, isolated; natural size.

6. First cirrus : magnified 3' , diameters.
Fig. 7. Kdge of mandibles; magnified 18 diameters.

Fig. 8 — \z. Scalpellum Stearnst Pilsbry, var. robusta n. var.
I 8. M.de; magnified 78 diameters.

I ig. 9. Group of thrce males; magnified 52,5 diameters.

Fig. [O. Voung anima] creeping out of the Cypris-shell ; magnified 78 diameters.
I 11. Voung animal, recently attached; magnified 36 diameters.

I ig. 12. Extremity of capitulum with the primary scutum and tentacles of the
\ 'Hing animal of fig. 11; magnified 168 diameters.

Siboga-Expeditie. XXXI. P. P. C. Hoek, Cirripedia.

VI

3

X 1.1

■^t— '-

%

12

X 168

11
X 36

10

X 78

ik

Fig. i, 2 et 4 G. S. IloeU, ceter P 1'. C. Hoek del.

SCALPELU M.

Fn I'. W. M. Tra]), impr.

PLATE VII

1

1.

J.

1

3-

4-

5a

1

7-

ia

U

Fig.

'

IO.

1 1.

u.

'3-

1

14.

14,1

'5-

1 ig-

1 sa.

16.

1

'7-

Fig.

[S.

1

19.

Scalpellum acutum Hoek. Male, magnified 7S diameters.

uncus n. sp., magnified 5,6 diameters.
.SV. uncus n. sp. Male magnified 52,5 diameters.
Sc. chitinosum n. sp., magnified 1,1 diameters.

nflatum n. sp., magnified 1,1 diameters.
.SV. inflatum n. sp. View of rostrum, sketch, r. rostrum; ;-./. rostral
latus ; se. scutum.

■aianicum n. sp., magnified 1,1 diameters.
.SV. javanicum n. sp. View of basis of carina, sketch.
.SV. javanicum n. sp. Male, magnified 52,5 diamei
Sc. curiosum n. sp., magnified 5,6 diameters.
Sc. curiosum n. sp. View of rostrum, sketch.

uriosum n. sp. View of basis of carina, sketch.
.SV. polymorphum n. sp. form A, magnified 3,2 diameters.
polymorphum n. sp. form A. View of rostrum, sketch.
Sc. polymorphum n. sp. form H, magnified 2,8 diameters.
.V. polymorphum n. sp. form C, magnified 2,8 diameters.
.V. dis tinc turn Hoek, magnified 3,2 diameters.
.NV. moluccanum Hoek, magnified 1,1 diameters.
Sc. hamulus n. sp., magnified 1,1 diameters.
,sV. hamulus n. sp. View of rostrum, sketch.
.SV. diota n. sp., magnified 5.6 diameters.
.SV. «//(>/(* n. sp. View of rostrum, sketch.
Sc. sessile n. sp., magnified 16,4 diameters.
.SV. ciliatum n. sp., magnified 15,5 diamet
.SV. pellicatum n. sp., magnified 1,1 diameters.
.SV. pellicatum n. sp. View of rostrum, sketch.
.SV. pellicatum n. sp. Caudal appendage; magnified 52,5 diami

Siboga- Expeditie. XXXI. P. P. C. Hoek, Cirripedia.

VII

G

x 1.1

9 a

ba, -»c

r.l.

f, n

8 a

8 6

31

X 2*

12

M -

TM

y-J

14-

14 o.

15
X .5.6

15 o.

17

y

19

X S2 i

18

A' 11

18 a.
X i.1

16
A- lS.t

P. P. C. Hoek del.

SCALPEL! I M

Fa. I'. W. M. Trap, impr.

PLATE VII

1 i

i.

1 i

i,i

1 i

2.

2a

Fig.

3-

1

v'

1 '

4-

Fig.

4''

5-

Fig.

6.

1

7"

1

7/>

1

8.

9-

IO.

1

lOtf

Fig.

1 1.

1

i i./

Fig.

1 2.

Fig.

'3-

Fig.

14.

1

14a

1 ig

1 5-

Fig.

'5'?

xlpellum crinitum n. sp., magnified 5,6 diameters.
.SV. crinitum n. sp. View of rostrum, sketch.
.v. tumult n. sp., magnified 5,6 diameters.
.SV. humile n. sp. View of rostrum, sketch.
.sV. arcuatutn n. sp., magnified 5,6 diameters.
Sic. arcuatutn a. sp. View of rostrum, sketch.
Sc. poculum n. sp., magnified 13 diameters.
.V. poculum n. sp. View of rostrum, sketch.
discolor n. sp.. magnified 2,8 diameters.
.sV. trapesoideum n. sp.. magnified 2,8 diameters.
.V. proclive n. sp., magnified 5,6 diameters.
.V. deforme n. sp.. magnified 5,6 diameters.
.V. gracile n. sp., magnified 5,6 diameters.
.V. elegans n. sp., magnified 3,2 diameters.
.V. sculptum n. sp., magnified 8,4 diameters.
jculptum 11. sp. View of rostrum, sketch.
.V. formosum n. sp.. magnified 5,6 diameters.
.V. formosum n. sp. View of rostrum, sketch.
.V. hexagonum n. sp., magnified 8,4 diameters.
.sV. praeceps n. sp., magnified 4,4 diameters.
.SV. incertum n. sp., magnified 5,6 diameters.
.SV. incertum n. sp. View of rostrum, sketch.
.SV. imbricatum n. sp., magnified 4,4 diameters.
.SV. imbricatum n. sp. View of rostrum, sketch.

Siboga- Expeditie. XXXi. P. P. C. Hokk , Cirripedia.

vin

X S.G

X S.G

/A

4

x w

b

x 2.a

'f

6

X 28

m

9
X 3.Z

30
x ut

14 a
X 16

10 a

X 8.4

7

X SS

Jl

"

IS

8

X 6.G

35 a.

X 4-4-

P. P. ('. Hoek, del.

SCALPELLÜM.

Fa. P. W. M, Trap, impr.

I'LATH IX

xlpellum fissum n. sp., with bowed carina, magnified 5,6 diameters.
fissum n. sp., with straight carina, magnified j,X diametres.
1 . candidum n. sp., magnified 1 1 diameters.

.-. .v. candidum n. sp. View of rostrum, sketch.
. virgatum n. sp., magnified 5,6 diameters.

5 — 8'. Alepas lithotryae n. sp.

;. Animal. lateral view; magnified 8,5 diameters.
Fig. 6. Mandible; magnified 80 diameters.
7. Maxilla ; magnified 1S0 diameters.

S. Cirrus of 6th pair, caudal appendage, penis; magnified 52,5 diameters.
8'. One of the rings of the penis; magnified 254 diameters.

9. Lithotrya nicobarica Reinhardt, magnified 1,5 diameters.

10 — 12. Lithotrya conica n. sp.

I [O. Animal, lateral view; magnified 1,5 diameters.

I ig. 11. Valves, magnified 5,5 diameters. A. Scutum; />'. Tergum; C. Carina.
Fig. 12. The scales of the peduncle immediately beneath the capitulum;
magnified 36 diameters.

Fig- 13. '3" and 14. Lithotrya pacifica Borradaile.

[3. Animal, lateral view; magnified 5 diametres.
1 : /. Rostrum; magnified 4,6 diameters.
Fig. 14. The scales of the peduncle immediately beneath the capitulum;
iiilied 36 diameters.

Siboga-Expeditie. XXXI. P. P. C. Hoek, Cirripedia.

I\

10

X 1 5

9

X 1 5

11
X 5.5

13
X 5

14
X 35

'-

w^

P. P. C. Hoek, del.

SCALPELLUM— ALEPAS- -LITHOTRYA.

Fa. P. W. M. Trap, imur.

PLATE X

i |„ — |,/. Poecilasma dubium n. sp. Four specimens with abnormal capitulum; magnified 10,5 diameters.

;. Poecilasma fissum Darwin.

Fig. 2. Maxilla; magnified 78 diametei

2a. Clawlike spines at thé upper angle of the maxilla, notch with the minute hairs; magnified
254 diameters.

3. Second maxilla. magnified 78 diameters.
Fig. 4. Spines at the extremity <>f the 8* segment of the && cirrus; magnified 254 diameters.
Fig. 5. Pedicel of 6»> cirrus, root of penis and caudal appendage; magnified 78 diameters.

6—7. Poecilasma eburneum Hinds.

1 ig. 6. Second maxilla; magnified 78 diameters.

Fig. 7. Spines at the extremity of the 8* segment of the 6* cirrus; magnified 180 diameters.

I . 8 — 16. MicroUpas diademae n. sp.

Fig. 8. Capitulum attached to a spine of Diadema saxatile L. ; magnified 3,6 diameters.

M.unlilile; magnified J2 diameters.
. [o. Maxilla; magnified 72 diameters.
I f. 11. Second maxilla; magnified 72 diameters.
Fig. 12. Cirrus of the first pair; magnified 50 diameters.
I . 13. < mus of the second pair; magnified 50 diameters.
14. Cirrus of the third pair; magnified 50 diameters.
[5. Cirri of the sixth pair and penis; magnified 50 diameters.
Fig. 16. Two eggs with the nauplius-larvae developed; magnified 234 diameters.

Siboga- Expeditie. XXXI. P. P. C. Hoek, Cirripedia.

ia

X 10 .5

P. P. C. Hoek, del.

POF.CILASMA— MICROLEPAS.

Fa, V W. M. Trap, impr.

Livr. XXXVI.

RÉSULTATS DES EXPLORATIONS
ZOOLOGIQUES, BOTANIQUES, OCÈANOGRAPHIQUES ET GÈOLOGIQUES

ENTREPKISES AUX
INDE9 NÉEKLANDAISE3 OKIENTALE3 en 1899 1900,

a bord du 8IBOQA

SOU3 LE COMMANDEMENT DE

G. F. TYDEMAN

PUBLIÉS PAR

MAX WEBKK,

Chef de 1'expédition.

*I. Iutroductiou et description de 1'expédition, Max Web er.
*II. Le bateau et son équipement scientifique, 6. F. Tydeman.
*11I. Résultats hydrographiques, G. F. Tydeman.
IV. Foramiuifera, J. Hofker.
*IVów. Xenophyophora, F. E. Sc huize.
V. Radiolaria, M. Hartmann.
*VI. Porifera, G. C. J. Vosmaer et I. Ijima ').
*V1I. Hydropolypi, A. Billard1).
*VIII. Stylasterina, S. J. Hickson et MUe H..M. England.
*IX. Siphonophora, M"ea Lens et van Riemsdijk.
*X. Hydromedusae, O. Maas.
*XI. Scyphomedusae, O. Maas.
*XII. Ctenophora, M'le F. Moser.

*XIII. Gorgonidae, Alcyonidae, J. Versluys, S. J. Hickson,
[C. C. Nutting et J. A. Thomson ').
*XIV. Pennatulidae, S. J. Hickson.
*XV. Actiniaria, P. Mc Murrich1).

*XVI. Madreporaria, A. Alcock, C. J. van der Horst et
*XVII. Antipatharia, A. J. van Pesch. [H. Boschma ').

XVIII. Turbellaria, E. Reisinger.
XIX. Cestodes, (J. W. Spengelf).
*XX. Nematomorpha, H. F. Nierstrasz.
*XXI. Chaetognatha, G. H. Fowler.

XXII. Nemertini, (A. A. W. Hubrecht-f) et Mme G. Stiasny.
XXIII. Myzostomidae, R. R. von Stummer.
*XXIV'. Polychaeta errantia, R. Horst1).
XXIV2. Polychaeta sedentaria, M. Caullery et F. Mesnil.
*XXV. Gephyrea, C. Pk Sluiter.
*XXVI. Enteropueusta, J. W. Spengel.
*XXVIiw. Pterobranchia, S. F. H arm er.

XXVII. Brachiopoda, J. F. van Bemmelen.
*XXVIII. Polyzoa, S. F. Harmer').
*XXIX. Copepcda, A. Scott1).
*XXX. Ostracoda, G. W. Muller.
*XXXI. Cirripedia, P. P. C. Hoek.
*XXXIbis. Rhizocephalen. P. N. van Kampen et H. Boschma.
* XXXII. Isopoda, H. F. Nierstrasz et G. A. Brender a
XXXIII. Amphipoda, C h. Pérez. [Brandis1).

* XXXIV. Caprellidae, P. May er.
*XXXV. Stomatopoda, H. J. Hansen.

* XXXVI. Cumacea, W. T. Cal man.
«XXXVII. Schizopoda, H. J. Hansen.
♦XXXVIII. Sergestidae, H. J. Hansen.

* XXXIX. Decapoda, J. G. de Man, J. E. W. Ihle et J. J. Tesch ■).
*XL. Pantopoda, J. C. C. Loman.
XLI. Halobatidae, D. Mac Gillavry.
*XLII. Crinoidea, L. Döderlein et Austin H. Clark.
*XLIII. Echinoidea, J. C. H. de Me ij e re.
*XLIV. Holothurioidea, C. Ph. Sluiter.
*XLV. Ophiuroidea, R. Kohier.
*XLVI. Asteroidea, L. Döderlein ').
*XLVII. Solenogastres, H. F. Nierstrasz.
*XLVIII. Chitonidae, H. F. Nierstrasz.
*XLIX'. Prosobranchia, M. M. Schepman.

*XLIX2. Prosobranchia parasitica, H. F. Nierstrasz et M. M.
*L. Opisthobranchia, R. Bergh. [Schepman.

*LI. Heteropoda, J. J. Tesch.
*LII. Pteropoda, J. J. Tesch.

*LIII. Lamellibrauchiata, P. Pelseneer et Ph. Dautzenberg ').
*LIV. Scaphopoda, M"e M. Boissevain.

LV. Cephalopoda, L. Joubin.
*LVI. Tunicata, C. Ph. Sluiter et J. E. W. Ihle.
*LVII. Pisces, Mas Web er.
♦LVIII. Cetacea, Max Weber.
*LIX. Liste des algues, Mme A. Weber1).
*LX. Halimeda, MUe E. S. Barton. (Mme E. S. Gepp).
*LXI. Corallinaceae, Mme A. Weber et M. Foslie.
•liXII. Codiaceae, A. et Mme E. S. Gepp.
LXIII. Dinoflagellata. Coccosphaeridae, J. P. Lotsy.
I/XIV. Diatomaceae, J. P. Lotsy.
*LXV. Deposita marina, O. B. Böggild.
*LXVI. Résultats géologiques, A. Wichmann.

Siboga-Expeditie

THE

OF THE SIBOGA EXPEDIT

BY

P. P. C. HOEK

A. CIRRIPEDIA PEDUNCULATA

With 10 plates

Monographe XXXIa of:

UITKOMSTEN OP ZOOLOGISCH,
BOTANISCH, OCEANOGRAPHISCH EN GEOLOGISCH GEBIED

verzameld in Nederlandsen Oost-Indië 1899 — 1900

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

UITGEGEVEN DOOR

Dr. MAX WEBER

Prof. in Amsterdam, Leider der Expeditie

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

BOEKHANDEL EN DRUKKERIJ

VOOltUFKK

E. J. BJRILL

LEIDEN

m

r4.

■Sr-

^F

5£

383
^5?

&0

V uiQ i

oio 1

ï,.-tf:

iiiiiiiiiiiniiiiiiiiiiiiniiiii

Publié Octobre 1907

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