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Cilap ak GS UR o antektenT avn de ap aR an ap ap Gea Se SR Ge Fe He ee BASE SR aR aaah Gee

RESULTATS DES Sea oe Sibo ga-Expeditie

-OOLOGIQUES, BOTANIQUES, OCEANOGRAPHIQUES ET GEOLOGIQUES

ENTREPRISES AUX / as

fi A we
aoe: v

Y INDES NEERLANDAISES ORTENTALES en 1899—1900, CRUSTAC rae
| Hahow dda ts GEA. SMITHS Sones
| : SOUS LE COMMANDEMENT DE RETURY by si)

G,. F. TYDEMAN
Nes a PUBLIES PAR E
Det MAX WEBER

| an UIRRIPEDIA OF THE SIBOGA EXPEDITION

_ SI, Introduetion et description de Vexpédition, Max Weber.
ile _ *I. Le bateau et son equipement scientifique, G. F. Tydeman. aa
| -* 111. Résultats hydrographiques, G. I’. Tydeman. BY

IV. Foraminifera, F. W. Winter. ;
bis. Xenophyophora, F. BE. Schulze.

. Radiolaria, M. Hartmann. ee P. : Gs HOEK
. Porifera, G. C. J, Vosmaer et I. Ijim@').

fh . Hydropolypi, A. Billard. etre
|| —‘* VIII. Stylasterina, S. J. Hickson ct Mile H. M. England.

) hy TX. Siphonophora, Mules Lens et van Riemsdijk. ,
p Re Hyadnaih sduees O. Maas. 1 CIRRIPEDIA PEDUNCULATA
*XT. Se: phomedusae, O. Maas.

*XIL. Ctenophora, Mile F. Moser.

*XIII. Gorgonidae, Alcyonidae, J. Versluys ct S.J. Hickson’),

XIV. Pennatulidae, 8. J. Hickson.
XV. Actiniaria, P, Me Murrich.

- * XVI. Madreporaria, A. Alcock *) et L. Déderlein.
_ XVII. Antipatharia, A. J. van Pesch.
_ XVIII. Turbellaria, L. von Graff et R. R. von Stummer.
Me . Cestodes, J. W. Spengel.
. Nematomorpha, H. F. Nierstrasz.
% . Chaetognatha, G. H. Fowler.

XXII. Nemertini, A. A. W. Hubrecht.
. Myzostomidae, R. R. von Stummer.
. Polychaeta errantia, R. Horst.
2. Polychaeta sedentaria, M. Caullery et F. Mesnil.
(. Gephyrea, C. Ph. Sluiter.
. Enteropneusta, J. W. Spengel.
. Pterobranchia, S. F. Harmer.
. Brachiopoda, J. F. yan Bemmelen.
II. Polyzon, S. F. Harmer,

. Copepoda, A. Scott.
. Ostracoda, G. W. Miller.
. Cirrhipedia, P,P. C: Hoek ').

XXXII. Isopoda, H. J. Hansen.
XXXIUL Senphitols, Ch, Pérez.
* XXXIV. Caprellidae, P. Mayer.

XXXV. Stomatopoda, H. J. Hansen.
| *XXXVI. Cumacea, W. T. Calman.

_ XXXVI. Schizopoda, H. J. Hansen.

eae Sergestidae, H. J. Hansen.

With 10 plates

Monographie XXXIa of:

UITKOMSTEN OP ZOOLOGISCH,
BOTANISCH, OCEANOGRAPHISCH EN GEOLOGISCH GEBIED

verzameld in Nederlandsch Oost-Indié 1899—1900

aan boord H. M. Siboga onder commando van
Luitenant ter zee 1¢ kl. G. F. TYDEMAN

UITGEGEVEN DOOR

_ XXXIX. Decapoda, J. G. de Man. C Ij
XL. Pantopoda, J. C. C. Loman. Dr. MAX WEBER SMITHSON LIB
. Halobatidae, J. Th. Oudemans. Prof. in Amsterdam, Leider der Expeditie . TAN I.

. Crinoidea, L. Déderlein et C. Vaney.
. Echinoidea, J. C. H. de Meijere.
. Holothurioidea, C. Ph. Sluiter.
. Ophiuroidea, R. Kohler. »
. Asteroidea, L. Doderlein.
. Solenogastres, H. F. Nierstrasz.
TI. Chitonidae, H. F. Nierstrasz.
. Prosobranchia, M. M. Schepman.
2, Prosobranchia parasitica, H. F. Nierstrasz.
. Opisthobranchia, R. Bergh.
*LI. Heteropoda, J. J. Tesch.
*LIT. Pteropoda, J. J. Tesch.

OMI. Lamellibranchiata. P. Pelseneer et Ph. Dantzenberg.
*LIV. Scaphopoda, Mile M. Boissevain.

LY. Cephalopoda, L. Joubin.
_ *LVI. Tunicata, C. Ph. Sluiter et J. E. W. Ihle').
_ LYVII. Pisces, Max Weber.

LVII. Cetacea, Max Weber.

LIX. Liste des algues, Mme A. Weber.

' *2LX. Halimeda, Mile E. S. Barton. (Mme BE. S. Gepp).
ie . Corallinaceae, Mme A. Weber et M. Foslie.
[. Codiaceae, A. et Mme EB. S. Gepp.

_ LXUI. Dinoflagellata. Coccosphaeridae, J. P. Lotsy.
© RLV. Diatomaceae, J. P. Lotsy.
_ _LXY, Deposita marina, O. B. Boggild.
XVI. Résultats géologiques, A. Wi chmann.

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

SPARE AR RSESE:

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Y

BOEKHANDEL EN DRUKKERIJ

VOOKURRN

a Ee J. BRILL
LEIDEN

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EBSe Se 2st ERE EE

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NL NATUTH A H

* Les, numéros avec un cedstiee ont deja paru; ceux marqués 1) ae. en partie

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

De Maatschappij ter bevordering van het Natuurkundig Onderzoek der Nederlandsche
Kolonién.

Het Ministerie van Kolonién.

Het Ministerie van Binnenlandsche Zaken.

Het Koninklijk Zoologisch Genootschap »Natura Artis Magistra’’ te Amsterdam.

De »Oostersche Handel en Reederij’ te Amsterdam.

De Heer B. H pe Waat Oud-Consul-Generaal der Nederlanden te Kaapstad.

M. B. te Amsterdam.

SIBOGA-EXPEDITIE

Siboga-Expeditie

UITKOMSTEN

UNI.NMINCEL UTANINEL CEANOGRAPHANEHY EE OLOGINCEE iL

VERZAMELD IN

NEDERLANDSCH OOST-INDIE 1899—1900

AAN BOORD HE. MM SIBOGA ONDER ‘COMMANDO VAN

Luitenant ter zee 1° kl. G. F. TYDEMAN
CITGEGEVEN DOOR

Dr. MAX WEBER

Prof. in Amsterdam, Leider der Expeditie

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

SS <

VOORHEEN

135 alo Ise UG bh,
LEIDEN

1
oe .
r SHG
Catt CRUSTACEA LIBRARY
} SMITHSONIAN INSTs,
yA Siboga-Expeditie i
t XXXIa

CIRRIPEDIA OF THE SIBOGA EXPEDITION

fee yO LOE

fe CIRRIEE DIA PEDUNGCULATA

With 10 plates

uate H}. J. BRILL
PUBLISHERS AND PRINTERS
LEYDEN — 1907

A. CIRRIPEDIA PEDUNCULATA

Genus Lepas Linnaeus

Of the species forming this genus six were already known to Darwin! (1851) and two
only have been added since the appearance of the “Monograph”: one (Lefas testudinata) by
AURIVILLIUS* in 1892 and one (Lefas denticulata) by GruveL* in 1901.

Most of the species of this genus have ‘enormous ranges’’, as Darwin (l.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 ansertfera Linn. East Indian Archipelago (Darwin); Java Sea, Moluccan Sea (“Challenger’’);
Sumatra, Ambon, Ternate etc. (WELTNER).

Lepas fascicularis Ellis & Solander. East Indian Archipelago, off Borneo and Celebes (Darwty).

Lepas denticulata A. Gruvel. Honda Bay (Philippines).

(Lepas Hilti (Leach) which was collected by A. Menztrs in the “South Seas” and
was found at Port Stephen, Australia (Darwin), Lepas fectinata Spengler, which, according to
Darwin, is common under the tropics and Lefas australis Darwin, which Darwin believed to
be confined to the Southern Ocean, have not hitherto been observed in the East Indian
Archipelago; nor has Lefas ¢estudinata 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 Leas collected by H. M.S. ‘Siboga”’ belong to two species
only: L. anserifera Linn. and L. fasciculards Ellis and Solander.

1 Darwin, C., A monograph 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. Ofversigt af K. Svensk. Vet.
Akad. Foérh. 1892, N° 3.
3 GruveL, A., Etude d'une espéce nouvelle de Lépadides. Trans. Linn. Soc. (2), VIII, 5, 1901.
I
SIBOGA-EXPEDITIE XXXIa. I

1. Lepas anserifera ‘Linn.

This seems to be by far the commonest species in the part of the tropics explored by
H. M.S. *Siboga’’; it was not only collected at numerous places during the cruise, it was also
several times found attached to the ship itself after being cleaned in the dock of Surabaja.

The places and stations where the species was taken are:

Stat. 19. Bay of Labuan Tring (Lombok), March 20, 1899. Fine set of specimens attached
to a piece of wood. Surface. Another set of smaller specimens with a barbed
carina attached to a piece of pumice-stone.

Lighthouse “De Bril” near Macassar. No date. Very small specimens attached to Spzrula, the
largest specimen has a capitulum of 6 mm. They belong to the var. dilatata:
scuta broad, carina barbed.

Stat. 110. July 6, 1899. Lat. 4°34’N., Long. 122° E.; South of Sulu Archipelago. Surface.
Two specimens; length of the capitulum of the larger, 25 mm.

Stat. 165. Daram Island (East Coast of Misool), August 22, 1899. Attached to a piece of
eulf-weed. Small specimens of 6 mm. and smaller: var. d/atata. Associated with
L. fascicularis Ellis & Solander.

Buton Strait, September 21, 1899. Surface, between Algae. Very small specimens attached to
Spirula. Var. dilatata with barbed carina.

Stat. 214. October 27, 1899. Lat. 6°30 N., Long. 121°55'E. Surface, attached to Spzriula.
Very small specimens: var. d/atata.

Stat. 228. November 14, 1899. Lat. 4°32'.5S., Long. 128° 30.5 E. Surface. Small specimens
attached to a species of Fuci. [The largest specimen has a capitulum of 7,5 mm.}.

No place, no date. Attached to the keel of H. M.S. “Siboga”. One specimen. Length of the
capitulum 20 mm.

July 10, 1899. Attached to the keel of H. M.S. “Siboga’, 40 days after having been docked
in Surabaja. Size of largest specimen: capitulum 21 mm. The larger individuals
are furnished with ovigerous lamellae.

October 15, 1899. Attached to the keel of H. M.S. “‘Siboga”, 107 days after the ship was
cleaned in the dock of Surabaja. Several specimens; length of the capitulum of
the largest individual, 25 mm.

Remarks. The specimens collected in the Bay of Labuan Tring (Lombok) caused me
some difficulty as they differed from the usual appearance of ZL. anserzfera 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 of
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
specimens from this locality show the straight line of small quadrilateral depressions of a dirty
brownish colour in the scutum, running diagonally across. the capitulum, which are very common
in L. anatefera. Darwin (l.c. p. 78) observed a trace of a diagonal line of such marks in a
single specimen of Z. /7z//z — but they have not been observed before in Z. azserzfera, so

far as I know.

ios)

2. Lepas fascicularis Ellis & Solander.

This species which is rather common in tropical seas was observed once only during
the cruise of the “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 Darwiy.

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

Genus Poecilasma Darwin

When proposing the new genus Poecz/asma, Darwin (1851) 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.:

Fors, Cirripedia, “Challencer’, 18835... 4). . 2 species.
AuvrIviLiius, Studien iiber Cirripedien, 1894,.... . 4 species.
Avrivitiius, Cirripedes “Princesse-Alice’’, 1898, . . . 1 species.

Gruvet, Lépadides nouveaux British Museum, 1902, 1 species.
PIOERY mOithipedias “Silogar, LOOZ) wAdcre. 4¥ncal-: assy Se Species:

Of some of these species it is questionable, whether they are really “good” species: for
example, as P. awrantium Darwin is considered by Gruvet’ to be a variety of P. Kaempfer?:
I think also, that it is doubtful whether P. amygdalum Auriv. and P. /enticula Auriv. are really
different from one another and from Darwin’s P. fisswm. 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 Poecé/asma are not easily understood. P. Kaempferi
Darwin (with awrantium Darwin), P. dudcum n. sp., P. carinatum Hoek and P. gracile Hoek
seem to form a natural group of true Poecz/asmas, 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. excavatum n. sp., P. minutum Gruvel, P. tridens Auriv. and P. vagans
Aurivillius. Of these species P. excavatum n. sp. and P. minutum Gruvel may turn out to be
much more nearly related than the others. The remaining species: P. crasswm Gray (with

P. unguiculus Auriv.), P. obligquum n. sp. P. eburneum Hinds might be considered to form a

1 GRUVEL, A., Cirripedes. Expéditions du Travailleur et du Talisman. Paris, 1902.

third natural group: the first with small, the second with rudimentary, the third without terga.
For the sake of convenience, such a classification may be used; but studying a few of the
species more carefully one soon discovers, that the affinities between the different species cannot
be made out by the shape or size or the greater or less development of parts of the capitulum
only. To show how complicated the relations are I need only refer to the new species P.
obliguum found by the “Siboga” and to be described later. With its miniature terga it seems
very naturally to bridge over the gap between P. crassum with small and P. eburneum without
terga; yet the arrangement of the spines on the cirri in P. odfzguum is quite different from
what it is in P. edwrneum and shows that it is perfectly impossible to consider them as nearly
related. In this regard P. odlequum seems to be nearly allied to P. fisswm; in the presence,
however, of a distinct line running from the umbo to the upper end of the scutum P. eburneum
approaches to P. fisswm much more than P. odliguum does.

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

Poecilasma Kaempfert Darwin (with P. aurantium Darwin), Japan, Madeira, 350 a 400 m.
(GruveEL), Gulf of Manaar, 775 m. (ANNANDALE).

Poecilasma dubtum n. sp., Malay Archipelago, 204 to 304 m.

Poecilasma carinatum Hoek, West Indies, Atlantic, Malay Archipelago, 600 to 1633 m.

Poecilasma gracile Hoek, Australia, Malay Archipelago, 521—750 m.

Poecilasma fissum Darwin (with P. amygdalum Auriv. and P. lenticula Auriv.), Malay Archipelago,
Philippines, Australia (WetTNeR’), Andamans (ANNANDALE*). Low water.

Poectlasma excavatum n. sp., Malay Archipelago, 289—304 m.

Poectlasma minutum Gruvel?

Poecilasma tridens Auriv., Philippines. Depth?

Poecilasma vagans Auriv., probably East India. Pelagic?

Poecilasma crassum J. EX, Gray, Madeira (Darwty), Azores (GruveEL). Depth?

Poecilasma unguiculus Auriv., Azores, 880 m.

Poecilasma obliguum n. sp., Malay Archipelago, 204—304 m.

Poecilasma eburneum Hinds, Malay Archipelago, ? Red Sea (WeLTNER *), 40—90 m.

Poecilasma Kaempferi (with P. aurantium) and P. carinatum are so far as at present
known the only species inhabiting both the Atlantic and the Indian Ocean. GRuvEL* says that
P. crassum {|from Madeira (Darwin)| and the Azores occurs also in the Philippine Archipelago,
Island of Bohol, but I suspect that this is an error; I do not know at any rate, on whose
authority this is stated.

1 WELTNER, W., Cirripedien einer Reise nach dem Pacific. Zoolog. Jahrbiicher. Abt. fiir Systematik, XII, 1899.

2 ANNANDALE, N., Malaysian Barnacles in the Indian Museum. Memoirs of the Asiatic Society of Bengal, I, 5, 1905.

3 WELTNER, W., Verzeichnis der bisher beschriebenen recenten Cirripedienarten, Archiv f. Naturgeschichte, 1897, Bd I, H. 3.
+ GRUVEL, A., Monographie des Cirrhipédes. Paris, 1905, p. 116.

The bathymetrical distribution is not known for all the species. P. vagans was found
attached to a Mauti/us and may be considered as a pelagic species, P. fisswm lives on crabs,
one of which was found under a stone at low water (Darwin), another (a Padiénurus-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—g90 m. and seems to be a shallow-water form.
P. dubium, P. excavatum and P. obliguum were found at depths varying from 200 to 300 m.
P. Kaempfert, P. carinatum, P. gracile and P. unguiculus go down to 500—goo m., P.

carinatum being the only one taken at so great a depth as 1633 m.

1. Poectlasma carinatum Hoek. Pl. I, fig. 1.
1883. HOEK, Cirripedia of the Challenger. p. 44, pl. I, fig. 8—r1o; pl. II, fig. 1; pl. VII, fig. 6—7.
This species was taken during the cruise of the “Siboga’”’ at

Stat. 177. Sept. 1, 1899. Lat. 2°24’'.5S., Long. 129° 38'.5 E. 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'.1S., Long. 127°16'.7 E. Depth, 828 m. Bottom: grey
mud. Attached to a small stem of Chrysogorgia flexilis (Wr. & St.). One specimen.

Only one group of 3 specimens and one single specimen were taken. As my figure of
this species reproduced on Pl. 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 Gruvet’ it is also found at the coast of Cuba at depths varying

between 600 and goo m.

2. Poectlasma gracile Hoek.
1883. HOEK, Cirripedia of the Challenger. p. 46, pl. Il, fig. 2—4.

This species was collected by the ‘Siboga’’ at

Stat. 38. April 1, 1899. Lat. 7°35'.4S., Long. 117°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 Cirrhipédes. Paris, 1905, p. I15.
5

6
3. Poecilasma dubium n. sp. Pl. I, fig. 2—4; Pl. X, fig. 1a—rd.

Capitulum distinctly swollen about the middle, compressed towards the apex. Scuta oval,
basal margin short. Terga with the basal point obliquely truncated. Carina narrow, its keel
flattened near the inferior extremity. Basis of the carina truncated, indistinctly forked. Peduncle
‘', the length of the capitulum. No thicker spines in the notch of the maxillae under the three
upper stronger spines.

General appearance (PI. I, fig. 2). Much like P. Kaempfert Darwin but with a shorter
peduncle and a 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 being broader than in P.
Kaempfert. Basal margin and carinal margin together forming an almost continuous curved
line. Interiorly the basal margin is furnished with a strong rim and a tooth at the occludent,
basal corner.

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

Carina (PIG) fig: 2) cextcemely narrow, its width only slightly increasing towards the
base. Its base truncated, miniature excrescences at both sides representing the prongs of the
fork of other species (PI. I, fig. 3a).

Peduncle cylindrical, short, less than one third the length of the capitulum, distinctly ringed.

Size. The largest specimen has a capitulum of 10,5 mm. length.

Mouth: Labrum with about 28 small bead-like teeth placed at a little distance from
one another; Palpi 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 of two or three together.

Maxillae (Pl. I, fig. 4) 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 smaller spines on the inferior, upraised part. Hairs on the surface of the maxilla not
very dense, in groups of two or three.

Outer 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. First pair standing far from the second, with nearly equal rami: the one divided
in six, the other in seven segments, the first segment of both being indistinctly divided into
two. Surface of each segment with a dense tuft of long hairs.

Second cirrus about three times as long as the first; the longest (posterior) ramus
has 13, the anterior ramus 11 segments.

Third cirrus with rami of 15 and 14 segments. Most segments are furnished on the
inner side with four pairs of spines: the first and the second pair very long, the third shorter,
the fourth very 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.
Caudal 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. 132°0.2E. Depth 204 m. Bottom: hard
coral sand. Two specimens and four with abnormal capitula.

Stat. 253. December 10, 1899. Lat. 5°48’.2S., Long. 132°13' E. Depth 304 m. Bottom: gray
clay, hard and crumbly. Four specimens.

General Remark. This species comes near to P. Kaempferd Darwin in some regards,
in others it seems to approach P. auwrantium Darwin, Gruvet who investigated numerous
specimens of P. Kaempfert from Cape Bojador thinks that P. awrantéum is a variety of P.
Kaempfert. 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: Kaempferd,
aurantium and dudtum 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 1,a—d, of Pl. X these differences may be judged.

Fig. 1a 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. 16 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. 1c 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. 1d 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

CRUSTACEA LIBRARY
SMITHSONIAN INST,

TQ W-119

so different, that I would hardly have taken the animal for an abnormal P. dudczwm, if I had
received it from a quite different Station. Comparing the different valves with those of a normal
P. dubium, the tergum in the first place is larger, its apex is slightly recurved and its basal
angle is not truncated but rounded. In the second place, the scutum is broader and its tergal
margin is much longer than in the typical specimens. Finally, the carina is not simply and
regularly bowed, but its upper part is recurved, and there is further a small isolated piece of
valve, which I think belongs to the carina, and which is placed between the tip of the remaining
part of that valve and the inferior angle of the tergum. In this specimen, moreover, the peduncle
is longer than in the other specimens, its length being about */; of the length of the capitulum.
The total length of this specimen was 7,2 mm., that of its capitulum about 5 mm.

I do not know what circumstances or causes made these four specimens develop in such
an abormal way. They were most probably dead, when they were taken by the “Siboga’’. |
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
already observed 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 1 describe another
case of such abnormality — without trying to explain its origin. This will be the task of future

investigators who study these animals in the fresh condition and at the place where they occur.

4. Poectlasma fissum Darwin. Pl. X, fig. 2—5.
Poecilasma fissa Darwin. Monograph, Lepadidae, 1851, p. 109, pl. I, fig. 4.

Darwin founded this species for a single specimen of Poecz/asma which he took from a
spinose crab found under a stone at low water in the Island of Bohol, Philippine Archipelago.

Numerous specimens were taken from a Padnurws, collected at Ternate during the cruise
of H. M.S. “Siboga’”’. There are about six larger 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 well to the specimens from Ternate that there remained for me no doubt
as to these specimens really belonging to Darwin’s Poeczlasma fissa. Vhere are little differences,
however, 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 been kept dry” and little differences
may occur within the limits of a species. I would hardly insist on these differences, had they
not caused what I suppose to be the same species to be described by AvriviLiius as a new
one under the name of P. amygdalum'. For this reason especially, the following details of

the animals structure may be of interest.

1 AurRIviLLius, C. W., Studien iiber Cirripedien. K. Svensk. Vetensk.-Akad. Handl. XXVI, N® 7, 1894, p. 10.
: )

Labrum 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 edge of the fourth
tooth and also one on the edge of the inferior angle.

The maxillae were unknown to Darwiy. 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 produced and bears about
ten unequally stout spines. Of these the one placed about the middle is by far the strongest.

The second maxilla (Pl. 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 6 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 (Pl. 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 (Pl. 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 6' cirrus.

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

General Remark. Avrtivituus (l.c. p. 12) points out himself that there is a close
affinity between his new species (P. amygdalum) and Darwin's P. fissum. Yet 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. fisswm, 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 Avurivitiivs’ and others more to Darwin's

SIBOGA-EXPEDITIE XXXIa@.

form. That the very peculiar arrangement of the spines on the cirri, which Darwin called most
abnormal, occurs in Avrivitiivs’ xova species also (“die eigentiimliche Anordnung der Cirren-
borstchen des P. fissum findet sich bei dieser Art wieder’’), is by all means a circumstance
strongly in favour of my view that they are really one and the same species.

Avrivittius took still another species of Poectlasma from the same specimen of Palinurus,
thrown on the shore of the Island *Noordwachter’’, one of the “Duizendeilanden”’ in the Java
Sea. He emphasizes that the main difference between this species and P. amygdalum is in the
structure of the cirri; these show according to him quite different characters, especially with regard
to the arrangement of 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 only seen in the sutures. AURIVILLIUS
gives a figure (l.c. Taf. VIII, fig. 28) to illustrate this detail of his P. /enticu/a — 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 Avrivitiius must have taken
place — but as he points out that the difference in the arrangement of the spines is the most
essential, one cannot help thinking that after all the reason for separating two forms of Poectlasma
as different species, which closely resemble one another in other regards and live together on
the carapace of the same specimen of Padcnurus, is not a very strong one.

According to Darwin Poectlasma fissum occurs at the Philippines; according to WELTNER '
it has been collected by FiscHer at New Caledonia, by WuireLeccE at Port Jackson, by himself
at Jaluit (on Padinurus) and by Scuavtnstanp at Honolulu.

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

5. Poectlasma excavatum n. sp. Pl. 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
the 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 united without chitinous interspaces, peduncle cylin-
drical, narrow where it is attached to the capitulum (Pl. I, fig. 5).

Scutum. The larger segment strongly bowed, with a short basal margin and pointed
apex. There is a trace of an internal basal rim, but no tooth at the rostral angle is present.
Like 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
as to fit exactly into the excavation of the tergum.

Tergum triangular with a very characteristic excavation at the scutal margin near the
occludent margin (Pl. I, fig. 6).

1 WELTNER, W., Ergebnisse einer Reise nach dem Pacific (SCHAUINSLAND 1896—97). Cirripedien. Zoologische Jahrbiicher.
Abteil. fiir Systematik u.s. w. Il, 1899, p. 441—447.

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 7a).

Peduncle short, about half the length of the capitulum, cylindrical; 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.

Size. 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. dudium.
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. dudzune.

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 terminally
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 ro and 11, in the cirri IV—VI
Ti tand 12.

The caudal 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 (Pl. 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. 132°13' E. Depth 304 m. Bottom: gray
clay, hard and crumbly.

and half a dozen specimens at:

Stat. 12. March 14, 1899. Lat. 7°15'S., Long. 115° 15.6 E. Depth 289 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 Remark. This species belongs to the same section of the genus as Darwin’s
P. fissum and the species P. amygdalum, P. lenticula, tridens and vagans of Avriyitutvs: 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

basal end of the carina render it easy enough to distinguish this species from those it shows

affinity to in other regards.

Together with Poectlasma excavatum, P. dubium and P. obliguum, a form of Poectlasma
was collected, about the nature of which I dare not pronounce an opinion with certainty. This
form is represented by a single specimen. The length of its capitulum is 7 mm., the peduncle
is about as long as the capitulum, cylindrical, distinctly ringed. It has the scutum divided into
two segments and, what has never been observed in any species of this genus, the tergum
also divided in two segments. The fissure runs in continuation to the fissure of the scutum
and has the same character in the terga of both sides. The terga do not look quite normal,
however, as they are only partly calcified: a relatively large part of the surface of the tergum
being occupied by chitinous substance.

In fig. 9, Pl. 1 I give a drawing of the outlines of this curious form, magnified slightly
over 5 diameters; in fig. 10 the apex of the scutum is represented with the division of the
tergum magnified 36 diameters. I feel at a loss to decide whether this form is normal, in which
case it would represent a very interesting section of the genus Poeczlasma, 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 P. excavatum, varietas.

At the same Station (253) still another form of Poectlasma was collected. It is represented
by a single specimen only; like P. fissum, P. excavatum etc. it has the capitulum composed of
seven valves and it is also nearly related to these species in other regards. Its peduncle seems
to be broken off, but the surface of the part remaining bears numerous 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. /isswm 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 introduce it into the

system under a specific name.

6. Poectlasma obligquum n. sp. Pl. I, fig. 11—22.

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

General appearance (Pl. I, fig. 11 and 12). Capitulum of oblique lenticular shape,
placed in such a way to the peduncle, that its base is covered at the right side more than at

the left. Scuta in the larger specimens distinctly furrowed.

sf)

Scutum. 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 (Pl. 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 margins blend into one another quite
gradually. 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 (Pl. I, fig. 13 and 14). Quite rudimentary, triangular. The basal angle is not
pointed but obliquely truncated.

Carina (fig. 15@ and 154). 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.

Peduncle 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. Pal pi 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 (Pl. 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
1t 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.

The inner side of each segment has a transverse row of more delicate spines or hairs and
these form tufts of hairs at the concave side, especially of the lower segments.

Third cirrus of the right side with both rami much shorter than those of the left side.
The rami of the third cirrus of the left side have 11 and g segments; form of the segments
and distribution of the spines much like in the second cirrus.

Fourth cirrus of the right side quite rudimentary, rami very unequal, both composed of
five segments, with small groups of hairs at the extremity of the segments. On the left side
the cirrus is composed of two nearly equal rami composed of 11 segments. The fourth left
cirrus has the same structure as the left one of the fifth pair (Pl. I, fig. 20): the groups of
spines on the dorsal side of the rami at 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, rudimentary (PI. I, fig. 21). It differs
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 11 segments. They bear, at the extremity of the segments towards the dorsal
side, the same groups of stronger spines as in the left-hand cirrus of the 4 and 5‘ pair; at the
anterior or concave side, each segment bears as a rule one pair of spines or a larger spine
accompanied by two or three more slender ones.

Caudal appendages (Pl. I, fig. 22) 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 sides.

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

Eggs 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°48’.2S.,.Long. 132°13' E. Depth 304 m. Bottom: gray
clay, hard and crumbly.

Stat. 251. December 8, 1899. Lat. 5°28'.4S., Long. 132°0.2 E. Depth 204 m. Bottom: hard
coral sand. One small specimen.

General Remark. This is a very remarkable species. Were it not for Darwry’s
(Hinps’) P. eburneum, 1 would have felt greatly inclined to consider it as representing a new
genus. As already observed by Hrnps (who therefore proposed the name 77z/asmzs for this
Cirriped) and as described in detail by Darwin, the terga are ‘entirely’ absent in P. eburneum
and at first I did not find them in P. odguum either. Yet on studying the capitulum more
carefully, I discovered the terga as extremely minute triangular pieces, hidden in the folds of
the membrane uniting the two scuta over the upper end of the carina. In this regard the new
species od/iguwm with its quite rudimentary terga bridges the cleft which separates P. crassum
with small (Darwin says “rudimentary” terga — but they are well-developed and even large
in comparison with those of P. odliguum) terga and P. eburneum with no terga whatever.
The structure of the parts composing the mouth in P. od/iguum differs in several regards

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. od/guum 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. fisswm the
same is the case. In P. oé/guum the first-third teeth of the mandibles are finely pectinated;
traces of such a pectination are, however, observed in P. fissum also. In P. obliguum 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. fisswm — 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. obfiguum.

So far as the shape and structure of the valves are concerned, P. eburneum of known
species of Poectdasma is the nearest relative of P. od/¢guum, with regard to the structure of the
body P. fissum has no doubt greater affinity to P. od/éguum than any of the other species.

7. Poectlasma eburneum (Hinds). Pl. X, Fig. 6—7.

Trilasmis eburnea Hinds, Voyage of Sulphur. I. Mollusca, 1844, Pl. XXI, fig. 5.
Poecilasma eburnea (Hinds), Darwin, Monograph, Lepadidae, 1851, p. 112, pl. 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. od/iguum and
having discovered its miniature terga, I was anxious, however, to investigate Hips 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 Darwin 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 palpi are rather long, so long as to touch when the two palpi
are turned towards one another. The inferior angle of the mandible 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 (Pl. 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.

With regard to the structure of the cirri the main difference between Darwin’s
description and what I have found is, that I think the unequality of the rami almost unimportant,
and further, that the segments of the rami of the 2? and 34 cirri are distinctly protuberant.
Altogether the cirri are short, the segments of the rami being but little longer than broad and
not very numerous; the last pair has rami of 13 and 14 segments in one of the specimens |
investigated. These segments have the ordinary 3 or 4 pairs of spines on the anterior face,
but as the segments are rather short these pairs stand close together and form groups of spines,
a “brush” as Darwin says, with the more or less numerous lateral marginal spines. The dorsal
side of each segment bears the ordinary dorsal tuft near the extremity (Pl. X, fig. 7).

The caudal appendages are short, less than half the length of the lower segment
of the pedicel of the sixth cirrus; they are slightly swollen about the middle, the rounded
extremity being distinctly narrower. The distal third part is thickly clothed with delicate bristles,

standing out in all directions.

During the cruise of the ‘Siboga”’ this species was collected at:

About Stat. 51: in Street Molo. Depth 54—90 m. 1 small specimen.

Stat. 79. June 12, 1899. Lat. 2°43'S., Long. 117°44' E. Depth 41—54 m. Bottom: fine coral
sand [Borneo Bank]. Attached. to the spines of a Czdaris bispinosa Lam. 8 specimens,
most of them small, three larger. The greatest diameter of the largest is about 7 mm.

Stat. 79%. June 12, 1899. Lat. 2°38'.5S., Long. 117°46' E. Depth 54 m. Bottom: fine coral
sand {Borneo Bank: 5 miles N.N.E. from Station 79}. 4 specimens, greatest diameter
of largest 7 mm.

Stat. 80. June 13, 1899. Lat. 2°25’S., Long. 117°43' E. Depth 40o—50 m. Bottom: fine coral-
sand. 4 specimens, largest not quite 5 mm.

General Remark. This species, which was known to Darwin from specimens from
New Guinea only, may now be considered to occur at different places in the Malay Archipelago.
It lives attached to the spines of Echznus, Cidaris and perhaps other forms of Echinidae and
seems to go down to depths of over 50m. According to WettTNER’ the Berlin Museum possesses

specimens of this species collected in the Red Sea (by Lepsius’).

Genus Dichelaspis Darwin

Darwin (1851) instituted the genus Dichelaspis for those Lepadidae which have 5 valves,
generally appearing like 7 from each scutum being divided into two distinct segments united
at the rostral angle; he distinguished five species of the genus. When my report on the
“Challenger’’ Cirripedia was published (1883) the number of known species had increased to
nine. Since that time the number has increased considerably; WeELTNER, publishing a list in
1897 of the then known species of Cirripedia, was able to count 18 species, or even 19, as
by a slight omission one of the 8 new species introduced into science by AuriviLiivs * was left
out by WELTNER. WELTNER also mentioned two new species which Sressinc * described in 1894;

1 WELTNER, W., Verzeichnis etc. Archiv f. Naturg. 1897, Bd I, H. 3, p. 243.

2 WELTNER, W., Ibidem, p. 241.

3 AurRIvILLius, C. W., Studien etc. 1894, p. 15—28.

4 Sreppinc, T. R. R., Notes on Crustacea. Ann. & Mag. Nat. Hist. (6) XV, 1894, p. 18—19.

but, of course, five other new species the descriptions of which have been published in 1900
by GruveL', two described by Lancuesrer® in 1902 and one by ANNANDALE in 1906°, could
not figure in his list. Thus 25 species in all of this genus are now known: in Grvvet'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 StExpinG *® 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 genus and I find that most of them must be considered as xovae 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.

AvriviLiius (I. 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 Déchelaspis. 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. StessinG 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 Aurtviriius in this matter. The structure of the body
of these problematic Dzchelaspis-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 Dechelaspis-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 Dichelasfis, 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 JZ. cor, the last stage — so far as known at present — being
occupied by Y. éud/ata Aurivillius, which species has no terga and no carina.

GRUVEL’s new species 2. Mazudront and D. Coutiered much resemble the form called
D. cor by Avrivitiius and these belong by all means to the same section of the genus, which
section now counts seven species: five of AvuRIvILLIUS 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 AvRIVILLIUS were even taken from the same Padénurus, 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 LANCHESTER, W., Crustacea of the Skeat Expedition. Proceed. Zool. Soc. London, II, 1902.

3 ANNANDALE, N., Stalked Barnacles in the Colombo Museum. Spolia Zeylanica, III, Part Xl, 1906.

* GRUVEL, A., Monographie etc. 1905, p. I40—I4I.

5 STEBBING, T. R. R., A new Pedunculate Cirripede. Ann. & Mag. Nat. Hist. (6), XIII, 1894, p. 443.
17

SIBOGA-EXPEDITIE XXXIa@,.

i>)

It is not my task to discuss the good standing of these seven species, some of which on closer
examination might probably be found to be identical; but I wish only to point out that there is,
no doubt, sufficient reason to admit a causal nexus between the simplified structure of the
capitulum and the mode of life of these forms.

Considering these seven species as a group of more or less degenerated forms, 18 (19)
species of typical Dichelaspis remain. Of the latter those species in which the valves have the
most complete development and show the greatest resemblance to the valves of the nearly
related genera Poectlasma and Lepas, are most likely to represent the more original form. In
this regard the species described by me as D. sesszlés, by ANNANDALE as D. tenutvalvata and by
LANCHESTER as ZY. occlusa are the first to be named: their scutum is rather broad, their tergum
has the triangular shape of the species of Zefas and their carina is likewise broad. Next come
the species D. Warwicki Gray and those which are nearly related to it: D. Hoekz Stebbing,
D. antiguae Stebbing, D. alata Auriv., D. Auriviliid Gruvel and PD. eguina Lanchester. In all
these species the scutum is composed of a narrow occludent segment and a much wider basal
segment which, as a rule, has a triangular shape. With the more or less developed and broad
tergum these valves cover a good deal of the surface of the capitulum. The carina of these
species terminates in a rectangularly inflected disc" extending over a good deal of the base
of the capitulum. These five species (with D. Forrest: (Stebbing), six“) form together another
very natural group of species in the genus D¢chelaspfzs. 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 for me to undertake.

Which species should come next? To judge from the form of the carina D. pellucida
Darwin would be nearly related to D. Warwickt Gray; to judge from the form of the tergum
D. orthogonia would be the nearest relative of the latter species and I think it would be very
difficult to decide which characteristic is the more important. There remain 12 species, all of
them with rather narrow valves leaving a great deal of the capitulum uncovered. These can
easily be divided into three natural and distinct groups. 2. orthogonta 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 H.M.S. ‘Siboga” in the Malay
Archipelago and to be described later belong. D. pellucida, which has the carina much like
that of D. Warwick, has the tergum of quite a different shape: like a battle-axe as Darwin
describes it; not only D. Grayz Darwin but 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 same holds good for D. Lowe? Darwin, D. Darwini Filippi, D. neptune Macdonald,

1 According to AURIVILLIUS the carina of his species 2. a/a¢a terminates in a fork. Should this really be the case, this species
would form a serious exception. But A. had at his disposal one specimen only and this specimen most probably has not been dissected
for the study of the carina. But without doing so, I think it is hardly possible to make out the shape of the terminal part of the carina.....
Perhaps he only had the impression that the terminal part was a fork, its two teeth being really united by a disc-like plate?

2 | think GRUVEL is right in considering SrEeBRING’s Zvichelaspis Forresti to be a Dichelaspis. 1 think it belongs to the same
section of the genus as D. Warwicki.

ithe)

D. Aymonini Lessona et Tapparone Canefri, D. sénwata Aurivillius, D. ¢régona Aurivillius and
D. Vaillant: 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 Dzchelaspis collected during the cruise of the “Siboga’” belong to five
different species: D. Weber n. sp., D. Nierstraszi n. sp., D. Tydemani n. sp., D. Versluysi n. sp.
and DY. orthogonta 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. Neerstraszt and D. Tydemani are both nearly related to D. Warwicki Darwin and doubtless
belong to the same section of the genus; 2. Wederd 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 Déchelaspis, 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. sesstlis (type-species), ). tenuzvalvata and YD. 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 inflected disc.
D. Warwicki (type-species), alata, antiguae, eguina, Aurivillit, (Forresti), Hoeki, Nier-
straszt, Tydemant (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), Grayz, 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), Weber, Versluyse (3 known species).
V. Species with five valves, the narrowness of which causes a great part of the capitulum to
be uncovered.
D. Lowet (type-species), Aymonini, Darwint, neptunt, sinuata, trigona, Vaillanti (7 known
species).
VI. Species with three valves only, terga wanting.
D. cor (type-species), angulata, aperta, Coutierer, 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. Warwickz, off Borneo Darwin ava Sea, near Batavia AURIVILLIUS).
b ] ’
ug)

D. alata, Java Sea: Thousand Islands (AvrRIvILLIvs).

D. eqguina, East coast of Malay Peninsula: Trengganu (LANCHESTER).
D. Nierstraszi, Malay Archipelago, different Stations, see later!

D. Tydemani, near Saleyer, see later !

? D. pellucida, Indian Ocean (Darwin), Oriental species with fairly extensive distribution (ANNANDALE).
?D. Grayi, Tropical, Indian or Pacific Oceans (DaRwiy).

D. Weberi, Off Great Kei Island, see later!

D. Versluyst, Malay Archipelago, different Stations, see later!

D. orthogonia, Malay Archipelago, different Stations, see later!

D. sinuata, Java Sea: Thousand Islands (Avrivitrivs).

D. trigona, Java Sea: Thousand Islands (AvrRIvILiivs).

D. angulata, Java Sea: Thousand Islands (AurRIvILLIvs).

D. aperta, Java Sea: Thousand Islands (AurtviLiivs).

D. cuneata, Java Sea: Thousand Islands (Avrivitivs).

D. Maindront, Sumatra (GRUVEL).

D. bullata, Java Sea: Thousand Islands (AurtviLtivs).

The seven species of Aurtvitiius enumerated in the above list were all of them taken
from one and the same stranded specimen of a Padinurus spec. They were found attached to
the branchiae or to the interior wall of the branchial cavity of that crayfish. The name of the
species of Palznurus is not given, but it is no doubt permitted to suppose that it was a littoral
form — no deep-sea species. Dechelaspis Maindronz, the species described by GRUVEL, was also
found attached to a Padinmurus (whether all of them, or only those collected by Mr. Mainpron
is not distinctly indicated by Gruvet) and also seems to be a littoral form. For D. Warwickz,
pellucida and Grayt no definite data with regard to their bathymetrical distribution could be
given by Darwin. They are most probably all of them littoral forms: D. WVarwicke was found
attached to a crab, Gvayz to the skin of a sea-snake, and fel/uctda also to a sea-snake — they
are most probably forms which live at the surface of the sea. J. eguzna lives on shallow-water
crabs and likewise D. occlusa.

The species collected by H. M.S. “Siboga’”’ were found at different depths:

Dichelaspis Tydemani n. sp. at a depth of 10—25 m.
Dichelaspis Versluyst n. sp. at a depth of 22—-32 m.
Dichelaspis Nierstraszi n. sp. at a depth of 27—59 m.
Dichelaspis orthogonia Darwin at a depth of 88—112 m.

Dichelaspis Webert n. sp. at a depth of 560 m.

The last-named is thus the only true deep-sea species of the collection, and as will be
seen from the description it is the largest of the known species. This is a peculiarity which also
holds good for many other deep-sea species of Cirripedia (e.g. Scalpellum- and Verruca-species).

The other known deep-sea species of this genus (2. sessz/is) was collected by the Challenger
near the Azores at a depth of about 1800 m,. All the other species are littoral forms, living

at the surface or going down to depths of 30, 50, 100 m. at most. In accordance with this

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 find in this regard as new facts that 2. eguina Lanchester
from the east coast of the Malay Peninsula is common on the east coast of British India
and that YD. pelluceda 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 “Siboga’’.

1. Dichelaspis Nierstrasz¢ n, sp. Pl. I, fig. 1—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. 2a).
In these the shape of the valves is also different.

Scutum (fig. 4a). 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@) 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. 3a represents the scutum of a middle-sized specimen,
remarkable for having the upper part of the occludent segment rather narrow.

Tergum (fig. 46). 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
extends 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. 34) the tergum has about the shape as the full-grown individuals.

Carina (fig. 5 and 5a). Much bowed, narrow, deeply concave within, extending up
between the terga for */,'4s of their length, with a very characteristic curvature directed inwards

just above the basal part. Downwards it terminates in a rectangularly inflected, deeply imbedded

disc, growing slightly wider towards its extremity, which terminally is not very deeply notched.
This disc (fig. 5a) is not flat but hollowed out in the middle; it extends across over more than
two-thirds of the base of the capitulum, .beyond the middle of the basal segment of the scutum.

Peduncle cylindrical, as a rule slightly longer than half the length of the capitulum,
about */,"4s of that length, or as long as the capitulum in specimens sitting crowded together,
rather long also in the old specimens, collected at Tual anchorage, Kei Islands, one of which
is figured Pl. Il, fig. 1. The peduncle is distinctly ringed at the surface; the chitinous covering is
studded with blunt beads of chitin externally and shows, in old specimens, scale-like excrescences
with grooves between them. Delicate hairs are planted on the blunt beads of the surface; they
are, however, more conspicuous in young specimens than in the full-grown. In the very old
specimens from the Kei Islands the surface of the peduncle, like that of the capitulum, has a
hairy felt-like coating.

Size. The largest specimen had a capitulum of 7,5 mm., most individuals however, are
no longer than 4 mm. and a good many of the specimens are still smaller. The capitulum of
the one figured, fig. 2a, only measured 2 mm., that of fig. 1, 6 mm.

Mouth. Labrum bullate, with small palpi bearing numerous bristles, some of them
very long, at the apex. Teeth about 18, bead-like distally, triangular and close to one another
in the middle.

Mandibles (fig. 6) narrow, with four 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 one 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 seven
moderately strong spines and a few hairs.

Cirri. First pair much shorter than and far removed from the second pair; seven
segments in the longer and six in the shorter ramus. The shape of the segments is nearly
quadrilateral, with the exception of the first segment 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
delicate spines 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 tuft of bristles, two or three of which are much longer than the others, is placed
on the summit; no bristles or one isolated bristle on the sides.

Penis short, thick, terminating in a conical part bearing a tuft of extremely delicate
hairs at its extremity.

General remarks. This species shows a certain resemblance to D. Warwickz; the
differences, however, being numerous and, so far as I could make out, constant, there can be
little doubt but that they represent different species. As in D. Warwick the scutum and tergum

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

valves in young specimens (fig. 2@) comes near to that of the same parts in D. Hoeki as

figured by Srespinc. It is undoubtedly the most common form of Dzchelasfzs 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 g to 112 m. They seem to be most numerous at depths not

exceeding 55 a 60 m. and are found attached to different objects: stems 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.

Stat.
Stat.

Stat.

State

Stat.

Stat.
Stat.

Stat.

Stat:

Stat.

60.

. April 8—12, 1899. Bay of Bima (north coast of Sumbawa). Depth 55 m. Numerous
specimens attached, with Scalpelluim rostratum Darwin, to different small stems.
April 27—28, 1899. Haingsisi, Samau Island, Timor. Depth 23 m. Numerous small

specimens.

. May 6, 1899. Lat. 7°0 S., Long. 120
One specimen.

. May to—June 7, 1899. Makassar and neighbourhood. Depth up to 32 m. § specimens.

. June 10, 1899. Lat. 3°27'S., Long. 117° 36’ E. Depth 59 m. Fine grey coral sand.
One fairly large specimen.

. June 13, 1899. Lat. 2°25'S., Long. 117°43 E. Depth from 50—40 m. Bottom: fine
coral sand. One large, three smaller specimens attached to a piece of coral.

. June 28—30, 1899. Lat. 6°7’.5 N., Long. 120°26 E. Depth from 16—23 m. Litho-
thamnion-bottom. 3 specimens, one attached to a small Lamellibranchiate Mollusc.

. 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.

. July 25—27, 1899. Anchorage off Lirung, Salibabu Island. Depth up to 36 m.
Bottom: mud and hard sand. 4 specimens.

. Aug. 7—9, 1899. Anchorage north of Salomakié (Damar) Island. Depth 45 m.

to)

34.5 E. Depth 120 m. at least; coral bottom.

2 specimens.

. Aug. 20, 1899. Lat. 1°42'.5 S., Long. 130°47'.5 E. Depth 32 m. Bottom: sand,
small stones and shells. Numerous small and larger specimens.

. Aug. 26—28, 1899. Gisser; anchorage between this island and Ceram-Laut. Depth 18 m.
Coral- and Lithothamnion-bottom. A dozen specimens with perfectly calcified valves.

. 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.

257. Dec. 11, 1899. Kei Islands, Du-roa Strait. Depth to 52 m. Bottom: coral. 3 specimens.

315-

8. Dec. 12—16, 1899. Kei Islands, Tual anchorage. Depth 22 m. Bottom: Lithotham-

nion, sand and coral. Several specimens, some of them very large.
. Dec. 26, 1899. Lat. 5°28'.2S., Long. 134°53'.9 E. Depth 57 m. Bottom: sand and
shells; stones. Numerous specimens, together with small barnacles (Salanus spec.).
. January 15—17, 1900. Lat. 8°25..2S., Long. 127°18'.4 E. Depth 2754 m. Bottom:
sand, coral and Lithothamnion. Numerous specimens attached to polyps etc.
. Januari, 20, 1900. Lat. 9°0'.35., Long. 126°24.5 E. Depth 112 m. Bottom: mud,
sand and shells. Two specimens.
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. Nrersrrasz,

one of the Zoologists on board H. M.S. “Siboga”’.

24
2. Dichelaspis Tydemani n. sp. Pl. Ul, fig. 8—13.

Capitulum much compressed with the apex highly produced. Scuta with the basal segment
triangular and the occludent segment broad, having the shape of a scalpel; terga with the lower
part about as wide as the occludent segment of the scuta; carina much bowed, terminating in
a disc, notched at its extremity.

General appearance (Pl. Il, fig. 8). Capitulum compressed, flat. Valves not very
close together. Valves thin and translucent, carina perfectly, other valves very imperfectly calcified.
The membrane covering the valves with rather long hairs.

Scuta (fig. 9). The occludent segment is long, flat, pointed at its extremity; its
occludent margin is straight, the carinal margin convex, whence the shape of the segment is
that of a scalpel. The basal segment is triangular, small; only a small part of the valve is
calcified: it stretches from the lower point of the occludent segment to one fourth of its length;
what might be called the junction of the two segments is calcified, but no calcification is seen
in the basal segment itself.

Terga (fig. ro). Scutal margin excised at a point vis a vis the apex of the scutum;
the excision separates a smaller occludent projection from a larger carinal projection or lower
part. Occludent margin simply and slightly curved. Incipient calcification at the umbo, where
the valve shows an indistinct third prominence.

Carina (fig. 11). 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
calcified; the basal portion is slightly wider than the upper part and is excised at its extremity.

Peduncle narrow, especially close under the capitulum; about 7/,'¢ the length of
the capitulum.

Size. Very small, the capitulum measuring not quite 2 mm. in length.

Mouth. Labrum bullate. Mandibles (fig. 12) with four 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. Aking
edge beneath this notch is straight and projecting, and bears six or seven unequal but rather
large spines.

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

The other cirri have very long and slender segments, bearing three pairs of spines
as avnule:

The caudal appendages are extremely slender but not longer than half the length
of the pedicels of the sixth cirrus. They bear a few (about four) very delicate hairs at their ends.

The specimens are attached to long, yellowish-brown hairs or spines, which are hollow
and bear triangular pointed teeth placed in irregular rows. They were taken, October 1899,
near Saleyer anchorage, at a depth of 10—25 m.

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. Typeman, the

distinguished commander of H. M.S. “Siboga’”’ during its cruise in the Malay Archipelago.

3. Dichelaspis orthogonia Darwin. Pl. Il, fig. 14—18. Pl. II, fig. 1, 1A, 1B and 104.
1851. DARWIN, Monograph, Lepadidae, p. 130, pl. II, fig. ro.

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 77, 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 */,8s of 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 Darwtn’s description: I have prepared these valves
from a 5 mm. specimen and figured them separately (fig. 15, a, 6, c).

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

The tergum (fig. 154) 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 Darwiy.

The carina (fig. 15¢ 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 peculiarity.

SIBOGA-EXPEDITIE XXXI@. 4

Five specimens in all were taken; some of them were attached to cylindrical stems of
a coralline organism most probably. The length of the capitulum of the largest specimen taken
by the “Siboga” is 6,6 mm., that of its peduncle is about 1,6 mm. A young specimen is
attached to the peduncle near its extremity.
The “Siboga” took these specimens at three different Stations:
Stat. 77. June 10, 1899. Lat. 3°27'S., Long. 117°36' E. Depth 59 m. Bottom: fine grey
coral-sand. I specimen.
Stat. 80. June 13, 1899. Borneo Bank. Depth 50—40 m. Bottom: fine coral-sand. I specimen.
Stat. 289. January 20, 1900. Lat. 9°0'.3S., Long. 126° 24'.5 E. Depth 112 m. Bottom: mud,
sand and shells. 3 specimens.

Formae dubiae. Though I have long been in doubt on the matter, I consider a
few specimens (two large, two smaller and a few very small specimens) as belonging also to
this species, which were collected by H. M.S. “Siboga’” at Station 318 at a depth of 88 m.,
as also 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 animal is figured on PI. II, fig. 18. In this specimen the proportion of the two segments
of the scutum is different from what it is in the individual represented in fig. 14 of the same
plate. Other differences are shown by the figures and are perhaps not important enough for
minute description. Of one of the specimens of Station 318 I have prepared the valves and
made with their aid the drawing fig. 1, Pl. HI. I have made a drawing further of the smallest
specimen of all (PI. HI, fig. 1A), taken also at Station 318 and of one of the slightly larger
ones (Pl. III, fig. 1B) of Station 294. In that of Station 318 the shape of the shells is still
quite different from that in the full-grown and those of Station 294, having a capitulum of
1,8 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:

Stat. 294. January 23, 1900. Lat. 10°12'.2S., Long. 124°27'.3 E. Depth 73 m. Bottom: soft
mud with very fine sand. Two small specimens.

Stat. 318. February 22, 1900. Lat. 6°36'.5S., Long. 114° 55.5 E. Depth 88 m. Bottom: fine
yellowish grey mud. Several large and smaller specimens.

4. Dichelaspis Webert n. sp. Pl. Ill, fig. 2—7.

Capitulum much compressed with the apex slightly produced. Scuta with the basal segment
narrower than the occludent segment and not quite half as long. Terga with three unequal
marginal projections on the scutal margin of the valve. Carina much bowed, internally very
concave, terminating downwards in a small spatula-like disc.

General appearance. Capitulum compressed, flat. Valves relatively small, narrow, a
large interspace between the carina and the other valves. Valves covered by a thin transparent

membrane only. Peduncle cylindrical, much shorter than the capitulum (PI. III, fig. 2).
26

Scutum (fig. 3@) 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.

Tergum (fig. 34) 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 fig. 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 trace of a fourth prominence on the carinal margin just
above the apex of the carina.

Carina (fig. 3¢ 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.

Peduncele 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 12 mm. when measured from the apex of the tergum
to the base of the carina. It is the largest of the known species of the genus.

Mouth. Labrum 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 second teeth slightly shorter than that
between the second tooth and the inferior angle. The inferior angle produced into an indistinct
double spine.

Maxillae (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.

Outer maxillae (fig. 7) rather broad, general shape rounded-quadrangular. Covered
with long 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.

Caudal 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. 132°48.8 E. Depth 560 m. Bottom: solid
bluish-grey mud, upper layer softer and brown mud. In all 9 specimens.

I have great pleasure in naming this fine and characteristic deep-sea species after the
leader of the “Siboga” expedition, Professor Max Wesrr. It was taken at a depth of 560 m.,
and thus may really be considered a deep-sea species.

It is a well-marked species: it shows a certain resemblance to D. orthogonia and belongs
to the same section of the genus, but it differs from it by its size, as well as by the shape
of the tergum and of the disc forming the base of the carina.

The present species and 2. sesszdzs Hoek, dredged by the “Challenger” in the Atlantic,
near the Azores, at a depth of 1000 fathoms, are the only known species of the genus Dechelaspis

living at considerable depths.

5. Dichelaspis Versluyst n. sp. Pl. Il, fig. 8—r13.

Capitulum 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
projections and a fourth one very small. Carina terminating downwards in an oval disc-like cup.

General appearance. Capitulum flat; valves small, a large part of the surface of
the capitulum remaining uncovered. Valves covered by membrane so as not to be seen distinctly
without isolating them. Peduncle cylindrical not quite half the length of the capitulum (PI. III, fig. 8).

Scutum (fig. ga). It consists of two bars placed in most of the specimens at right
angles to each other, in one of the specimens (figured in fig. 9) at an angle of more than go’.
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.

Tergum (fig. 94) 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.

Carina (fig. 9c). Much bowed, even slightly more than is the case in D. Webert,
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 embedded
and forms a cup of a very peculiar shape: it is oval with at each side a small wing, like the
small handles of a bowl (PI. H, fig. 10a, while fig. 106 shows the cup-shaped basal portion
of a specimen of LD. 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
specimens 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
smaller. The largest specimen is over 7 mm.

The mouth and its parts in general resemble greatly the same parts in D. orthogonia:
crest of the labrum with a row of small bead-like teeth; palpi with the two sides parallel,

bearing towards the one side numerous very long bristles.
28

Mandibles (fig. 11, @, 6 and ¢) 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 Pl. HI 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.

Of 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. 1°42'.5S., Long. 130°47’.5E. Depth 32 m. Bottom: sand,
small stones and shells. About 12 specimens.

General Remarks. I have some doubt as to -whether I am right in considering this
as a species; but as there are full-grown specimens with egg-lamellae in the collection and as
these differ 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
fluctuating 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. Verstuys, one of the Zoologists of the scientific staff

Otel MS: “Siboga™.

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

ay)

different in several more or less important details, I consider it as a variety of the last described
species. Comparing the capitulum we see that the occludent segment of the scutum of this
specimen is more than twice as long as the basal segment, and that it does not grow wider
towards the apex but has about the same width throughout its length. The tergum of this
specimen, though deeply furrowed like the same valves in JD. Versluyst, does not show the
fourth prominence just above the apex of the carina. The carina itself not only has almost
the same general shape, but its basal portion has exactly the particular form which is so
characteristic of D. Versluyst.

Only one specimen represents this form and this specimen, the length of the capitulum
in which is about 6 mm., has been dissected to prepare the valves and to make out its identity:
so that the “type” of this form no longer exists and this alone would be a reason for not
introducing it into science as a new species. As, further, its relation to D. Versluysi is very
close I think it right to indicate it as D. Versluyst Var. The single specimen was taken at:

Stat. 258. Dec. 12—16, 1899. Tual anchorage, Kei Islands. Depth 22 m. 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 Poeczlasma,
Dichelaspis and Lepas and is nearly related to the first of these three.

In 1894 Wettner! described a second species of this genus and gave it the name of
M. carino-dentatum. A third was collected by H. M.S. ‘Siboga” in 1899.

The diagnosis given for this genus in the “Challenger” Report holds good for the forms
discovered later, with one exception; the triangular form of the scutum which was so very
striking in JZ. striatum is, strictly speaking, gone in JZ. “éneatum (and so far as can be judged
from the sketches of WerLTNER, the same is the case in JV. carino-dentatum), there being a
distinct though short basal margin. Hence, I propose to have the diagnosis changed so far that
the scuta 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

A. Dorsal margin of the carina developed into a broad flattened part

forming the continuation of the downwards inclined portions of the

teroum along their carnal margin << \-) (epee wenmene gear) mmr Suen caceu7 carer
&. Dorsal margin of the carina not forming a broad flattened part.
a. Dorsal margin of the carina having a tooth-like excrescence. . J. carino-dentatum.
6. Dorsal margin of the carina without a tooth-like excrescence. . MZ. “ineatum.

1 WELTNER, W., Zwei neue Cirripedien aus dem Indischen Ocean. Sitz. Ber. Ges. Naturf. Freunde zu Berlin, 1894, p. 80.

3°

M. striatum 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. MW. carino-dentatum was found on the stem of a
Fyalonema from the Gulf of Bengal, dredged at 3200 m. JZ. éneatum 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 genus has
only been found in Asiatic Indian Waters.

1. Megalasma striatum Hoek.
1883. HOEK, Cirripedia of the “Challenger”. p. 51, pl. I, fig. 5—o, pl. VI, fig. 8—o.

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 189g at different stations, viz.

Stat. 251. December 8, 1899. Lat. 5°28'.45S., Long. 132°0.2E. 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. 132°13' 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. 5°54'S., Long. 132°56'.7 E. 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 Poeczlasma, four species of Scalpellum,
one of Balanus etc.; at Station 253: three species of Poeczlasma 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. Pl. 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. Pl. 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

margin, which in the larger specimen is more distinct than in the smaller. The carinal margin
bowed and longer than the tergal margin; where these margins meet an obtuse angle is
formed and from this angle a not very prominent ridge runs to the occludent margin. This
is the only ridge on the outer surface of the scutum. Internally a not very prominent ridge
runs along the lower half of the occludent margin, whereas a much more prominent and bowed
ridge separates a small basal portion from the rest of the valve. Where these two ridges meet,
near the occludent margin, a relatively strong tooth having the shape of a little nail, is formed.

Tergum (fig. 1 and 34) triangular, relatively small. Carinal margin and scutal margin
have about the same length; the former does not show the flattened border which is so
characteristic for JZ. strzatum.

Carina (fig. 2, 3c and 4) broad towards its basal end, much bowed, terminating
upwards in a narrow flat part which runs up to the basal ends of the terga. The flattened
dorsal margin is narrow and has about the same breadth throughout its length. The base is
abruptly truncated. The scutal margin at one third of its length from the base shows a small
tooth or excrescence which fits into an indistinct excavation in the carinal margin of the scutum.
This detail of the structure seems more strongly developed in younger specimens — it cannot
at any rate be made out so sharply in full-grown specimens without isolating the valves.

Peduncle very short, slightly extending from underneath the capitulum.

Size. The largest specimen has a capitulum of 1 cm. in length.

Mouth. Labrum (fig. 5) bullate; crest with a row of numerous (+ 40) small triangular
teeth; Palps small, hairs numerous at the tip and along the interior margin.

Mandibles (fig. 6) with four teeth, the inferior 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.

Maxillae (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.

Cirri. First pair far removed from the second pair with very short rami. Rami not so
much differing in thickness, much more so in length. 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.

Caudal appendages (fig. 8). Very short, terminating abruptly and broad, and
bearing a not 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.

ios)
(oe)

This species was taken at:

Stat. 74. June 8, 1899. Lat. 5°3'.5 S., Long. 119°0’ 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 Remarks. 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 “agrees in every
respect with Horx’s s¢rzatum 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 (JZ. 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” — no figure is given.
I would not be astonished, however, if this form and my new species JZ. Zineatum proved to

be identical *.
Genus Alepas Sander Rang

Darwin (1851) enumerated four species of the genus A/efas: two of these he saw and
investigated himself (4. mznuéa Philippi and A. cornuta Darwin), the two others (4. parasita
Sander Rang and A. tuéulosa Quoy et Gaim.) were known to him only from figures and
descriptions published by Quoy & Gaimarp, SANDER Rano and Lesson. The ‘Challenger’ collected
a fifth species of this genus which was described by me in 1883 as A. fedunculata. Six other
species have since then been added to the list, viz. two by Aurivitiius*® (A. guadrata and
A. japonica) and four by Gruvet* (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 11 species of this genus known to him.

Since then, ANNANDALE® has described three more species of this genus, viz. two (1905):
A. gigas collected in Bali Straits and A. malayscana 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 4. ovadis (taken W. from
the Key Islands at a depth of 984 m.) and A. ¢enuzs (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 during press).
3 AuriviLLius, C. W., Studien iiber Cirripedien. K. Svensk. Vetensk.-Akad. Handl. XXVI, N° 7, 1894, p. 28—3z2.
4 GruveL. A., Sur quelques Lépadides nouveaux de la collection du British Museum Trans. Linn. Soc. VIII, 8, London, 1902.
5 ANNANDALE, N., Malaysian Barnacles in the Indian Museum. Memoirs of the Asiatic Society of Bengal, I, 1905, p. So—Sr.
—— Preliminary Report on the Indian Stalked Barnacles. Ann. and Mag. Nat. Hist. (7), XVII, April 1906, p. 399.

SIBOGA-EXPEDITIE XXXI@. 5

them A. morula, A. intermedia and A. lithotryae. The first was collected between Borneo
and Lombok at a depth of 538 m., the second N.W. from the Key Islands at 90 m. depth,
the third near South Lucipara Island at a depth of 894 m. attached to the valves of Lithotrya
nicobarica. The last species has, not unlike A. gwadrata Auriv., horny, nearly quite hidden
scuta; A. morula can be recognised at once by the very peculiar structure of the capitulum;
and A. intermedia stands so far as the structure of the 5" and 6' cirrus is concerned between
the species with quite normal rami and those in which the inner ramus is quite rudimentary.

Including the 5 species from the “Siboga’’ we now have 19 species of A/efas in all.
The absence of calcareous parts or valves which facilitate the separation of the species in other
genera (in Scalpellum e.g.) makes this distinction a troublesome one in Adepas. The outward
shape of the capitulum, the-length and proportions of the peduncle are liable to change with
the age, under the influence of the fluid used for the conservation etc. The question whether
all the species described are really good species in the case of A/efas is more difficult to answer
than for the other genera. Yet, considering the circumstances under which they were taken
(different objects or animals to which they were found attached, different depths, geographical
distribution) there can be 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 according 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.

*Alepas ovalis n. sp. 984 m. W. from the Key Islands.

Alepas pedunculata Hoek. 740 m. Off New South Wales.

*Alepas morula n. sp. 538 m. Between Borneo and Lombok.

Alepas minuta Philippi. 355—250—100 m. Mediterranean, Atlantic Ocean.
Alepas xenophorae Annandale. 333 m. S. W. Coast of (English) India.
*Alepas gigas Annandale. 290 m. Bali Straits.

*Alepas tenuis n. sp. 204 m. South of Ceram.

*Alepas intermedia n. sp. 90 m. N.W. from Key Islands.

Alepas japonica Aurivillius. 80 m. Japan Sea, Hirado Street.

* Alepas malaysiana Annandale. 55 m. Gaspar Straits.

*Alepas lithotryae n. sp. Reef. Near South Lucipara Island.

Alepas tubulosa Quoy & Gaimard. On Padinurus (Coast?). New Zealand.
*Alepas quadrata Aurivillius. On Palinurus (Coast?). Thousand Islands (Java).

Alepas cornuta Darwin. ? West Indies: St. Vincent.

Alepas parasita Sander Rang. Surface (on J/edusae). Mediterranean, Atlantic Ocean.
Alepas Belli Gruvel. ? Cuba.

Alepas microstoma Gruvel. ? Madeira.

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

Thus, we see that of the 19 species described in the literature 9 or about the half have
been observed 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.

1. Alepas morula n. sp. Pl. 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 5'® 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 middle 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 mandibles (fig. 11 and 11a) 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. 11@), 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 stronger than the others. The edge beneath the notch bears numerous strong 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.

Cirri long, with short and numerous segments, with the exception of those of the first
pair which are rather short and broad.

First cirrus placed far from the second; its pedicel is relatively long, its rami short,
slightly unequal, the longest has also the broadest segments; both rami have eight segments,
the last being very minute. The segments on both rami bear strong bristles placed in a row
near the anterior extremity of each segment. The segments of the strongest ramus have further
a dense clothing of bristles on the side which is directed towards the more slender ramus.
Whereas the small terminal segment of the more slender ramus bears three strong spines, the
same segment of the stronger ramus has one slender spine only; further a number of extremely
small hairs are placed at its extremity. In the row of bristles at the extremity of the sixth and
seventh segments of the stronger ramus two or three bristles are wanting; minute scales are
present at the places left open. Beneath the basal articulation of the first cirrus a long filamentary
appendage is situated.

Second 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
13 a 14, in the sixth 16 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
its extremity, 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 extremity of
the segment. The ventral face of most segments shows a row of very short stiff hairs, giving
it the appearance of being serrated.

The rami of the 5 and 6 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 scattered over its surface and a dense tuft of slightly stronger hairs at its extremity.

One of the specimens I investigated was furnished with eggs which were united in one
egg-mass. The eggs were extremely numerous and very small. Most of them contained Nauplit
and many seemed to have come out before the animal was caught and put into the preserving
fluid. The form of the eggs was long-oval, their length was 0,3, the greatest breadth 0,13 mm.
Larvae without eyes or without black pigment in the eyes.

This species was taken at:

Stat. 316. February 19, 1900. Lat. 7° 19'.4S., Long. 116°49'.5 E. Depth 538 m. Bottom: fine,
dark brown sandy mud.

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

37
2. Alepas intermedia n. sp. Pl. IV, fig. 13—16.

Capitulum oval, surface smooth, no scuta. Orifice narrow, not projecting. Peduncle stout,
nearly as long as the capitulum. Inner rami of the 5'* and 6' cirri slightly shorter than the
outer ram.

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.

Size. The figure 13 represents one of the larger specimens. It has a capitulum about
1 cm. and a peduncle about 0,8 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.

Mouth. 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 palpi 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 maxillae (fig. 16) 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

of the rami causes the whole cirrus to be short. The first pair is placed near the mouth and
at some distance from the second. Its rami are nearly equal and composed of five segments
only. The first segment is very long, longer than the other four segments together and not
quite distinctly composed of four or five short and broad segments soldered together. Segments
2—4 are of a very characteristic pentagonal shape, segment 5 is short, small, quadrangular.
The slightly shorter ramus is at the same time a little narrower. It can be said to have one
segment more than the longer ramus, as the last segment of those which are soldered together
to form the first segment of the longer ramus has remained free in the shorter one. Each
segment bears a broad group of long bristles on its outer surface; the first segment shows 4
or 5 such groups of bristles. The last segment has the bristles planted close to its extremity.
On the inner surface the bristles are less numerous and not placed so regularly, on the outer
segments they form a row near the extremity. Along the dorsal margin, each segment bears
a long bristle planted slightly above the middle of its length.

The pedicel of the first cirrus is much shorter than that of the other cirri. The filamentary
appendage ~is seated beneath the basal articulation of the first cirrus; it is long, conical and
pointed at its extremity.

The 2"4 cirrus has ten segments in both rami, the 3'¢ 11 in the shorter and 13 in the
longer ramus; the 4'* has 12 and 13 segments, the 5t* and 6t 13 and 15 — at least these
were the numbers in the specimen I investigated more carefully. The pedicels are long, the
segments short, slightly longer only than broad. Each segment is protuberant at the anterior
face, a little beneath the articulation with the following segment. On 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. On 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 6'* cirrus might as well be said to have 13 and 15 as 12 and 14 segments.

The caudal appendages are rather long and delicate. In one of the specimens I
dissected the one consisted of 8, the other of 10 joints. In length they equal the pedicels of
the 6' cirrus, the 1o-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
basal as well as the terminal portion can be said to be ringed, there being an intermediate
part where the rings can hardly be distinguished. Very long and delicate hairs are scattered
over the surface, forming a somewhat irregular tuft at the extremity in the little furrow between
the two points or lobes.

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

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

oe)
the Nauplii ready for hatching; these larvae showed no trace 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. 5° 36.5 S., Long. 132°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 5'* and 6* 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. xvenophorae Annandale — a figure of that species might at once

settle this question |.

3. Alepas lithotryae n. sp. Pl. 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 5*® and 6» pair shorter than the foregoing
ones. Inner ramus of the cirri of the 5‘? and 6 pair slightly shorter than the outer rami.

The capitulum of this species in some of the specimens almost insensibly slopes into
the peduncle (Pl. LX, fig. 5), in others it is distinctly separated from the peduncle by a contraction.
Its 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 Lethotrya.

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.1I.M.S.S. Investigator”, Calcutta, 1907. I think ANNANDALE’s
A. xenophorae and my A. intermedia are different species. (Note added during press).

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

Mouth. Labrum distinctly bowed with a row of about 30 rounded chitinous knobs
at the place of the teeth and with a series of delicate hairs inserted in front of the knobs.
Palpi short, broad at the base, conical with several bristles along the outer margin and a
tuft of such 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
first and second tooth at twice the distance of the other teeth. The inferior angle is slightly
raised at its extremity and terminates in a not very pointed tooth, much ressembling the other
three teeth. 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 the extremity of the inferior angle. Near
the outer edge the surface of the mandible is furnished with numerous hairs which are placed
in groups of two or 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 upper spines, of which the first
is by 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 double
row along the lower part. Hairs in groups of two or three on the surface near the free edge;
a row 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.

Outer 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, 2°4—4* pair
longer than the others, 5" and 6t pair considerably shorter than the foregoing ones.

First pair placed close to the mouth, at a little distance from 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
segment 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 1st to the 6, The lower
are densely covered with hairs, the distal in a less degree. The last segment has four strong
spines at the tip; these are not quite so strong and a little less curved than those at the tip
of the shorter ramus.

The 2™4¢ to 4t cirrus has nearly equal rami of 9 to 10 segments. The shape of the
segments is almost quadrangular, with the exception of the first segment of each ramus, which
is from 2 to 3 times as long as broad and of the last segment, which is small and rounded
at the tip. The bristles form transverse rows near the extremity of each segment and a tuft

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 5‘ segment,
two or three are much thicker and stronger and have the shape of claw-like spines.

The 58 and 6" cirri are shorter than the foregoing ones, the 6‘ being not inconsiderably
shorter than the 5", the latter equalling about */,'4s the length of the cirrus of the 4 pair. The
rami of the 6 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 2®4—4' cirrus. From the 4'* to the 8 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.

Caudal 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 Lzthotrya nicobarica. | observed from 2 to 7 specimens — most of
them very small ones — attached to one Lz/hotrya. 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 Zz¢thotrya is trying to get hold of.

The Lithotrya nicobarica was collected at:

Stat. 225°. November 8, 1899. 2700 m. N. 185° 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 “Kur-Reef”, a very small one to
one of the specimens of ZL. ¢vancata, collected at Haingsisi, Samau Island, Timor.

Observation. I think that this species comes close to Alefas guadrata 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 Aurtvmrius. 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. guadrata. Avrivitiius says (l.c. p. 32) that this organ is “hie und da mit riickwarts
gerichteten Bérstchen versehen’. Perhaps there exists a certain relation between the one or
both species and Alepas malaysiana described of late by ANNANDALE.

41
oe 6
SIBOGA-EXPEDITIE XXXI@.

42
4. Alepas ovalis n. sp. Pl. IV, fig. 17 and 18.

A single specimen of a species of the genus A/efas different from the known species
was taken by H.M.S. “Siboga” at Station 267. According to the label the specimen was found
attached to the spines of Poroctdaris elegans, on which the specimens of 4. morula were
also found. It differs from that species at first sight 1° by its form which is more regularly
rounded oval; 2° by the absence of the tubercles on the surface; 3° by the somewhat larger
orifice of the capitulum; and 4° by the shorter and more cylindrical peduncle. When I received
it, the specimen was no longer attached to the Echinid-spine (as was the case with the specimens
of A. morula); so 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, I think, from the
figures 17 and 18 of Pl. IV. The length of the capitulum and the peduncle together is nearly
11 mm., the capitulum alone measuring about 8 mm. Scuta absent or entirely hidden under
the chitinous membrane.

The species to which this specimen belongs has no doubt a certain resemblance to
A. japonica 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
do so without destroying the specimen.

The specimen was taken at:

Stat. 267. December 20, 1899. Lat. 5°54'S., Long. 132°56.7 E. Depth 984 m. Bottom: grey
mud with a brown upper layer.

As I have pointed out already in the introduction to the genus A/epas, of all the known
species this form, next to A. Lankesterz, inhabits the greatest depth. This is also one reason
why I think identity with 4. japonzca highly improbable.

4. Alepas tenuis n. sp. Pl. IV, fig. 19.

Still another species of the genus A/epas is represented in the collection of H. M.S.
“Siboga’’. There is again only one specimen and it is very small — whether full-grown or not
I am unable to decide. It resembles Alefas Lankestert Gruvel to a certain extent — yet it is
much smaller and the resemblance might on closer examination turn out to be superficial only.

Like Alefas Lankestert 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 figure will, I hope, enable this form to be recognised,
should it again be found.

It was taken at:

Stat. 251. December 8, 1899. Lat. 5°28'.4S., Long. 132°0'.2 E. Depth 204 m. Bottom: hard
coral sand.

General Remark. I do not think it a good custom in general to describe such forms
as novae species, of which it is impossible to give a full description for want of material. When
discussing the geographical distribution and the bathymetric range of the known species of the

genus, for the sake of convenience names were also given to the two last mentioned forms. The
number of known species of the genus Adepas not being very large and the species more or
less recognisable 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 2°¢—6'" pair with uniarticulate rami of very unequal size.

This cirripede resembles at first sight a species of A/efas; 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 disposal
was found by Prof. Max Weber attached to one of the spines of Dzadema saxatile (Linn.) at
Station 53. I propose to call the species:

1. Microlepas diademae n. gen., n. spec. Pl. 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
large, 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 labrum not distinctly bullate or swollen with
a straight crest without distinct teeth and with small triangular palpi. The mandibles and the
maxillae were relatively large, and extended beyond the labrum and the outer maxillae; they
were of a very peculiar shape.

The mandibles (fig. 9) have no teeth but a smooth and rounded edge, along which
are numerous very delicate hairs in several rows. Its inferior angle is acuminated and ends in
a slightly stronger bristle, which however can hardly be called a spine.

The maxillae (fig. 10) have the edge also rounded, without steps separate from one
another by notches and without stronger spines at the upper corner. Along the rounded edge
numerous delicate hairs are inserted in several rows; the lowest corner has two slightly stronger
bristles and another is seen at a little distance from it. A rather stout and not very long
apodeme is attached to the maxilla. Both maxilla and mandible are thin and delicate, their
extremities reaching beyond the tip of the mouth on the whole.

Outer maxillae (fig. 11) represented by very small rounded structures with delicate
hairs along their inner surface and at the tip. A group of apparently stronger hairs on a little
rounded excrescence near the summit — these hairs, however, were all broken off.

First pair of cirri (fig. 12) quite rudimentary, represented by a one-jointed conical limb

with a few short hairs at the tip.

Second-sixth cirrus (fig. 13—15) of about the same structure: each consisting of a
two-jointed pedicel and two rami, each of which is represented by a single segment only,
the one however about twice as long and more than twice as broad as the other. The cirrus
of the second pair has the lower segment of the pedicel shorter and the upper longer, the
third cirrus has about the same structure; in the 4*—6t 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
a separate 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 on 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
are seen 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. 15) rather broad, short, not extending beyond the extremity of the cirri ot
the 6 pair, truncated at the extremity where it bears a tuft of short hairs. Numerous very
short hairs scattered over its surface.

The little animal was sexually well-developed and provided with ovigerous lamellae,
which, however, had not the shape of leaves but rather of clusters of irregular shape in
which the eggs formed several layers. As I described above, one of these clusters had been
forced out of the sack of the animal, the other being still seen in the cavity. The eggs
are numerous and small. They have an elongated form, at least in the highly developed

45
condition I observed them in (fig. 16). Their size was: long 0,26—o,28 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 Dzadema 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 Adepas. 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 A/efas — without quite destroying the type.
But I think it probable that there is correspondence in this regard also between the two genera.
In Adlepas cornuta the inner rami of the 5° and 6" 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 M/zcrolepas diademae show this
atrophy in both rami and to a much greater extent! The cirri of Axelasma 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 Axelasma. In the genus Gymnolepas, as described by AuriviLiivs, 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 2°4—6"™ 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. AvuriviLLius compares his new genus with Axedasma and says
that a reduction of all the cirri has occurred in these two genera. There can be no doubt,
I think, that a much more considerable reduction has occurred in JLicrolepas diademae!

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

(to ten), strong teeth in a single row; they are always by far the strongest pair of parts in the
mouth, being generally about double the size of the maxillae. Now the mandibles of Jccrolepas
diademae have no teeth whatever, the inferior angle only being furnished with a somewhat
stronger spine than those which are planted along the free edge; further, the mandible of this
Cirriped can hardly be said to be larger than the maxilla. The latter in all other Cirripedia
has larger spines at the upper corner and numerous more or less strong spines along the edge:
in Microlepas diademae it has the edge regularly curved and furnished with several rows of
extremely delicate hairs — its inferior angle showing a slightly stronger spine-like hair, another
being inserted at a little distance from that angle.

The extremely rudimentary condition of the first pair of cirri and the fact that caudal
appendages are wanting complete the description of a pedunculate Cirriped, which so far as
the 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 animal only —
the capitulum gives at least the impression of being that of an ordinary A/efas. 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 Déadema 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 Mzcrolepas 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 difference
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 /é/a 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
terga), as 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 or two complemental
males” (Darwin).

Of this genus two species were known to Darwin in 1851. Since that year no new
species have been described, nor have the original species of Darwin been often met with. In
his list of 1897 WeLtTNer' mentions the occurrence of /é/a Cumznge Darwin in the Red Sea,
in the neighbourhood of the Philippines and at Zamboanga (also Philippines), and of /é/a guadri-
valvis (Cuvier) at Van Diemensland. Of the latter species GruveL” found numerous specimens

1 WELTNER, W., Verzeichnis u.s.w. Archiv f. Naturg. 1897, Bd I. 5
2 GruveEL, A., Révision des Cirripédes appartenant a la collection du Muséum d’histoire naturelle. Nouv. archiv. du Muséum
(4), IV, 1903.

(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 Gruvet! he treats the
genus /é/a 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 /é/a-species were collected at
different places in the Malay Archipelago. They belong to two different species: 7. Cumingi
and another which is different from the two known from Darwiy’s Monograph. It comes near
to /. 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:

Lbla

1. Hermaphrodite with complemental male (or males). . . . . . J. guadrivalvis (Cuvier).
2. Unisexual with dwarfed males.
a. Valves of the female coloured blue along the lateral margins
andwongthemupper interior surface, - . .. . . . . £ Cumingi Darwin.
ju Valvesswithoutsblue maroims..92) << . . = | . . 2 JS. stbogaen. sp.

1. Lola Cumingt Darwin.

Darwin found the specimens of this species “invariably attached to the peduncle of Pod/-
copes 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.
lola Cuminge was found attached to two of the specimens frorn 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 Pollicifes 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 (l.c.) mentions the occurrence of this species in the Red Sea; as Podlicifes
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 Darwiy, 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 /é/a guadrivalvis is given moreover

1 GruveL, A., Cirripédes des expéditions scientifiques du “Travailleur” et du “Talisman”. Paris, 1902.

by Gruver! and in most regards this holds good also for the male of /é/a Cumungz. There
is however one detail which I found different from Darwin's description. Darwin speaks of an
imbedded portion of the peduncle of the little male passing obliquely through the chitine
membrane and corium lining the sack of the female, and running along amidst the underlying
muscles and inosculating fibrous tissue, attached to them by cement at the extremity. I have
always found the little male attached to the wall of the sack by means of a disc of cement,
but I could not observe that it passed through that wall. I think that the description given by
GruveL, where he says (for /6la guadrivalvis) that the mantle (Darwin's “sack’’) sometimes
forms a proliferation, through the centre of which passes the extremity of the peduncle of the
male, explains what has been observed by Darwin. According to Gruver the tubular part of
the male “s’enfonce dans le manteau de l’héte”’. 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
meet with the muscles of the female’s or hermaphrodite’s peduncle.
This species was collected at the following places:
Stat. 51. April 19, 1899. Shore-exploration in Madura Bay and other localities in the southern
part of Molo Strait. A few small specimens attached to Pollecipes mitella.
Stat. 86. June 18—19, 1899. Reef-exploration Dongala, Palos Bay, Celebes. Specimens loose,

i.e. not attached to Pollicipes mitella. (N.B. No specimens of Pollictpes were
collected at Station 86).

2. Ila sibogae n. sp. Pl. IV, fig. 20—22. Pl. V, fig. 1—8.

Female. 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. Closely resembling that of 7. Cumzngz Darwin.

This species is unisexual like 7. Camzngz Darwin, which it also resembles in many other
regards. The absence of the blue colour, together with a few slight differences I perceived in
the structure of the parts of the mouth, the cirri and caudal appendages, as also the circumstance
that /. Cumingi lives attached to Pollicipes mitella as a rule, made it necessary to consider
the present form as a different species. Later investigation of a richer and if 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.

Female

The animals are somewhat variable in shape, that part 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
specimens there is a distinct constriction beneath the broader part, almost in the middle of the

1 GRUVEL, A., Cirripedes des expéditions scientifiques du “Travailleur’ et du *Talisman’’. Paris, 1902.

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

The colour 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 swollen 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 margins, the
dark colour having however a blackish-brown, not a blueish tinge.

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 /. Cwzmzngz. But whereas he says, that those of the latter species are “ringed
with pale and dark blueish brown, which on pressure becomes slightly opalescent with pale
blue and fiery red”, those of /. szdogae never show a trace 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 7. Cumzngz. 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 distance from one another as well as in delicacy.

Fig. 21, A and B of Pl. 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 ¢ 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 distinguished
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 J, Cumingz, 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. stbogae than in Lf. Cumeingz.

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 labrum has from 3—7 small nob-like teeth: in younger specimens 3 or
4 only, 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 no teeth on the crest of the labrum in
I. Cumingz and that the same part in /. guadrivalvis is “a little roughened with minute points”.
Now the teeth of the labrum of /. széogae are hardly more than minute points; I may add

SIROGA-EXPEDITIE XXXI@. 7

50
that I observed them also on the crest of the labrum in one of the specimens of /. Cxmzngi
from Station 86 (Pl. IV, fig: 22).

The palpi of the labrum are small, rounded at their ends; the hairs on the palpi
form a not very dense tuft at the extremity, those on the palpi of both sides hardly touching
one another when in the natural position. The outer margin bears a row of extremely
minute hairs.

Mandibles. In one of the specimens from Station 47 the upper edge of the second
tooth was not pectinated. The inferior angle is only slightly produced in all the mandibles I
investigated; it is pectinated as figured (fig. 22a).

Maxillae (PI. V, fig. 1). Edge very indistinctly indented; it supports, besides the three
upper large spines, a number of moderately strong spines, which can hardly be divided into
stronger and more delicate ones. 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 infra-oesophageal ganglion between the bases of the
first pair of cirri, corresponds exactly with Darwuy’s description of the same parts in /. Cumaengz.

Cirri. The first cirrus has the rami unequal in length by from 2 to 5 segments, by
about two segments in /. Cwmznge, according to Darwin. | dissected in all six specimens of
I. stbogae and I found the following numbers of segments for the first cirrus: 21—17, 2c—16,
17—I4, 17—13, 17—12 and 14—12. These numbers show greater variety than is the case
in most other Lepadids.

(In a specimen of /. Cumzngz 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 /. Cuzmzngz. 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 four 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 /. Cxmengz.
(On the 6" cirrus of a specimen of 7. Cumzngz collected at Station 86 I also found four pairs of
bristles on some of the segments — however, the number of segments showing this arrangement
was very small).

The caudal appendages have from 17 to 13 segments. The upper segments which
in Lf. Cumingt “are slightly constricted round the middle, so that they resemble in a small
degree an hour-glass” (Darwry), in /. sedogae do not show the hour-glass shape as a rule. In
some specimens the two last joints show a trace of that peculiar shape, which I found distinctly
developed in the last six segments of the caudal appendages of specimens of 7. Camdngi. As
in this species the caudal appendages of /. sedogae are as long as or slightly longer than the
pedicels of the sixth cirrus.

The egg-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 from Station 61
I counted about 240 eggs. In each lamella the eggs are kept together by an extremely delicate
and clear membrane, which surrounds each egg as a capsule. At one place the margin of

50°

51
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 /. guadrivalvis, according to Darwty) 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 0,14 X 0,1 mm.; development was only beginning. A
larger female taken from the corals of the island of Billiton contained eggs of 0,21 X 0,16 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 7. 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 /. szogae. 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 /. széogae 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
large 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 Pl. IV shows two
larger males as they were found zz sztz; 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
provided 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 Darwty found
the little male of 7. Cuming?, viz. “in a nearly central line, at the rostral end”. I found them

as a rule more to the left and at the bottom of the sack. When two were present (Pl. IV,
fig. 20) they were so placed that the anterior portion of the one touched the posterior end of
the other. I never observed that a much constricted part of the males passed through the skin
(sack or mantle) of the female; there is as a rule a thickening of cement round about the base
of the peduncle. The extremity of the peduncle with its cement-ducts passes through this cushion
of cement, but I never observed that it also went through the wall of the sack (or mantle).

The figures 3—8 of Pl. V are drawn from a male of 3,5 mm. Darwin calls the part in

front of the oblique fold the thorax, the rest the peduncle of the animal. The thorax supports
two pairs of rudimentary cirri and, more to the so-called ventral side, the parts of the mouth.
The labrum is very broad with a nearly straight edge and small palpi. The latter have a few
short bristles or hairs at their pointed extremity. The mandibles have three teeth, more diverging
than in the females; the inferior edge is quite undeveloped: a mere nob with a rudimentary
point or spine at the extremity. The maxillae show the three upper spines and two more spines
at the inferior end 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 spines, two of
which are again stronger than the third which is planted between the two. The outer maxillae
are relatively large; they show a row of small bristles along the curved outer side, they have
the so-called olfactory orifices at the end of flat tubular processes, exactly as in the female and
just 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 orifices (genital porus and anus) that these cirri answer to the
fifth and sixth pair in other Cirripedes — but this view is not supported by the circumstance,
that I observed a rudimentary capsule in the basal segment of the first pair (in a small specimen
of 1,4 mm.), much resembling the so-called auditory sack. Hence I 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
accompanied the 3,5 mm. male of figure 3. In the largest of the two (the front part of which
is figured Pl. 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 edges of the segments,
slightly more prominent towards the dorsal side.

In the fig. 4 of Pl. V I have indicated the free edge of the thorax as seen through the
basal segment of the last cirrus. Following that edge behind the last pair of cirri we see that
it forms a round excrescence: a rather stout papillus, which projects freely at the so-called
dorsal side of the body. This papillus most probably represents the penis — I would say so
with greater emphasis, if I had been successful in discovering the genital porus at its surface

or free extremity but this is not the case. In the other larger (nearly full-grown) specimen
I have investigated, 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 Gruvet (I. 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 Gruver in all essential points —
but for its immatureness — resembles the grown-up male. Darwin observed the larvae of
I. guadrivalvis 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 /é/a 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 find a trace of digestive glands
and that the stomach of the specimens he investigated 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 covered 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 double pear-
shaped vesiculae seminales in accordance with Darwiy’s and Gruvet’s descriptions — these
parts may be considered as well known. Perhaps the nervous system is not so well known as
yet. Gruvet 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

rectum between the two ductus ejaculatorii. He could not make out the chords (“connectifs’’)
uniting the one ganglion with the other, but he admits that such nervous chords exist. I did
not observe them either, but I found that a rather large ganglion is situated between the eye
and the wall of the stomach, so that the eye nearly rests on or against this ganglion. From
this ganglion (the optic ganglion’), which seen laterally as in fig. 3 of Pl. V is oval, but which is
broadly heart-shaped when seen from above, two very distinct nerves run, as may be supposed
but could not be made out, to the cerebral ganglion.
The “Siboga’’ collected this species at the following places and stations:

Stat. 19. March 19—21, 1899. Bay of Labuan Tring, west coast of Lombok. On shore.
Stat. 47. April 8—12, 1899. Bay of Bima. On shore.
Stat. 50. April 16—18, 1899. Bay of Labuan Badjo, West coast of Flores. On shore.
Stat. 115. July 9—11, 1899. East Side of Pajunga Island. Kwandang Bay. On the reef.
[N.B. Dr. C. Pa. Sivrrer sent me, about 1884, specimens of an /é/a found by him
at Tandjong Pandan (Billiton) on corals which belong undoubtedly to this species.|

Genus Scalpellum Leach

Of all the known genera of Cirripedia this is the richest in species. In his Monographie
des Cirrhipédes of 1905 Gruvet distinguishes in all 93 species of Sca/pe//wm — that this number
by no means includes all the existing forms is proved by the collection of the “Siboga”’. It
contains 38 species of this genus and 32 of these have not been described before.

This augmentation seems especially considerable, if we take into consideration the relatively
small area that has been explored by the Dutch man-of-war: all these new species were collected
within the Malay Archipelago.

The number of species of the present genus hitherto known with certainty as occurring
in that archipelago was sixteen, viz.:

Sc. villosum Leach. Eastern Seas (Darwin) (? India, Timor, New Holland).
Sc. trispinosum Hoek. Philippine Archipelago.
Sc. rostratum Darwin. Philippine Archipelago.
Sc. compressum Hoek. Between Celebes and Sangir Islands.
Sc. album Hoek. North of Karakelang, Talaut Islands.
Sc. hirsutum Hoek. West of Batjan, East of Celebes.
Sc. rubrum Hoek. Philippine Archipelago.
Sc. truncatum Hoek. Between New Guinea and Australia, East of Cook Peninsula.
Sc. moluccanum Hoek. South of Ceram.
Sc. australicum Hoek. Between New Guinea and Australia, East of Cook Peninsula.
Sc. distinctum Hoek. North of New Guinea, eastern half.
Sc. indicum Hoek. Kei Islands.
Sc. dubtum Hoek. Between New Guinea and Australia, East of Cook Peninsula.
Sc. balanoides Hoek. Kei Islands.
ss iniseebag eS North of New Guinea, western half.

As 17'® species Sc. rautilwm Darwin might be added to this list. Darwin says of this
species that its habitat is unknown and adds: associated with Déchelaspis orthogonia. As the
latter species was collected at three different Stations in the Malay Archipelago, I think it
probable that Sc. ratiZum belongs also to the fauna of this region. H.M.S. “Siboga” collected
specimens of three of these species, viz. Sc. vostratum Darwin, which was taken at four different
Stations and seems to be rather a common form in these seas; Sc. désténctum 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. Peron? (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. Stearns¢ Pilsbry) occurring in the
Japan Sea: this form is described later as a variety of Pitspry’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:

Sc. Peroni (Gray) Jedan Islands . Toc, fGen HEC s | (274)
Sc. rostratum Darwin Bay of Bima, Sumbawa; North of Buton; . .| 47, 204 I3—94 m.
\WES® Cit Sailavers Souin OF Wineyrs 5 6 = 5 o ||| Bile, Aol

Sc. pollicipedoides n. sp. Pasteoipcwislandsy awe ak es Gk Sess 8'| 274 57 m.
Sc. aries n. sp. NorthpofeBbutonie ers) seen cee lee Goon be os] 204 75—94 m.
Sc. uncus n. sp. South-coast of Timor; Bay of Bima, Sumbawa . | 285, 47> 34, 296 m.
Sc. zmbricatum n. sp. Neate tnislandshra eg) ye Wes Ah he "| 251 204 m.
Sc. diota n. sp. INGER INET AISIEINGIS 95 Gee) 06) Soll oi ioe as en 251 204 m.
Sc. candidum n. sp. NeameXei islands) Sse eh avs oe) at ete al oe ie 251 204 m.
Sc. Stearnsi Pilsbry, Near Wer Islands: Wadura-Seawa ee cee So 9:

a 204—450 m.

Vim AOCUSTZMVaten |e VWestaon Nakassans Kei Islands jy <ee |) 251, 254

Sc. hamulus n. sp. Keeimislandsien avein= 20 ni id Isle eten ce pem roll 7s 2506 397 m.
Sc. polymorphum n. sp. Keilslands;)Northyof Sumbawa ss) ei 250, 45 30% 794 m.
Sc. praeceps n. sp. Between Halmaheira and New Guinea. . . . | 159 ATL sae
Sc. pellicatum n. sp. ken lislainclss ISAge Ci IoMNeOy 6 so 6 5 2 5 al) 250, OA | sys vise) ioe
Sc. fissum n. sp. West of Halmaheira; South of Celebes. . . . | 19722402472) me
Sc. prochve n. sp. INieeye leaker Webs (eles 5 6 « 6 6 4 5 a | 87 655 m.
Sc. deforme n. sp. iNjGaim leo: Ibe, (CODES 5 2 6 5 co o's o E 87 655 m.
Se. curiosum n. sp. NOt Oi Sisley 5 Sf 6 co 5 6 6 9 6 Oo Oo 45 794 m.
Sc. crinitum n. sp. Northpoh Sumibawaene) seca meee site sets 45 794 m.
Sc. mcertum n. sp. Between Kofiau and New Guinea. . . .. . 1601 798 m.
Sc. chitinosum n. sp. North of Sumbawa; West of Aru Island . . .| 45, 271 794, 1788 m.
Sc. poculum n. sp. Near IRotE, Somln OF Wire oc a 46 6 6 6 300 gi8 m.
Sc. javanicum n. sp. INGHHn OPI ss Giver eo 6 ols Goo Eola 18 1018 m.
Sc. humile n. sp. ast. ot Seller 6 0 6 5 6 6 Bb 6 6 6 « 211 1158 m.

>. gracile n. sp.

. acutum Hoek

5. Sessile n. Sp.

>, formosum N. Sp.
;. inflatum N. Sp.

>. moluccanum Hoek
. elegans Nn. sp.

. distinctum Hoek

. virgatum n.

5. arcuatum n.

. ciliatum n. sp.

sp.

. sculptum n. sp.
>, hexagonum n. sp.

. discolor n. sp.

. trapesoideum Nn. Sp.

ast of Saleyer 9. {-)-sieen 211 1158 m.
Between Gebé Island and Waigeu Island; 151, 845,

East of Saleyer; North of Celebes 211, 122 | 1158, 1264 m.
South of Ceram ~ n a Reeim Ke earcumtoearel ets 241 1570 m.
South of Ceram; South of Ambon . . . . .| 24I, 22 1570, 2081
West of Aru Island . 275 1788 m.
West of Aru Island. 271 1788 m.
West of Buton Island 208 1886 m.
Northern entrance of Strait of Macassar; . . . | 88, 1300,
West of Buton Island; between Ceram and Misool. | 208, 175 | 1886, 1914 m.
Soitth sof Ambon! “co tyes a ee ee 227 2081 m.
Syotuo, te Wie 5 og co o os @ 6 8 eo 8 295 2050 m.
South of Timor 295 2050 m.
South of Celebes . 214 2796 m.
Banda Sea 221 2798 m
Banda Sea 221 2798 m
Batida” Seas os ne eee ee 221 2798 m

38 species of Scalpellum were thus taken at 32 Stations; two of them (Sc. rostratum

Darwin and Sc. Stearnsz Pilsbry, var. vodusta n. var.) were collected each at four different

Stations; two of them (Sc. acatum Hoek and Sc. destenctum Hoek) were taken each at three

different Stations; six of them (Sc. wacaus, Sc. polymorphum, Sc. pellicatum, Sc. fissum, Se.

chitinosum and Sc. formosum) were collected each at two different Stations; all the others

(28 species in all) were collected only once. Some of the Stations yielded several species

of Scalpellum :

aye Syeltes

Stat.

State

Stat.

455

Lat. 7° 24'S. and Long. 118° 15.2 E. Depth 794 m. Bottom: fine grey mud, with
some Radiolariae and Diatoms, four species of Scalpellum were taken, viz. Sc.
chitinosum, crinitum, polymorphum and curzosum.
Lat. 5°28'.4S. and Long. 132°0'..2 E. Depth 204 m. Bottom: hard coral sand,
four species of Scalpellum were taken, viz. Sc. candidum, diota, imbricatum,
and Sfearnsz var.
Lat. 5°40.7S. and Long. 120°45'.5 E. Depth 1158 m. Bottom: coarse grey mud,
superficial layer softer and brown, three species of Sca/pellum were taken, viz.
Se. acutum, humile and gracile.
Lat. 6°24'S. and Long. 124°39' E. Depth 2798 m. Bottom: solid bluish grey
mud with Foraminiferae, three species of Scalpellum were taken, viz. Sc. discolor,
hexagonum and sculptum.
Lat. 5°26.6 S. and Long. 132°32'.5 E. Depth 397 m. Bottom: greyish green
mud, three species of Scalpellum were taken, viz. Sc. hamulus, polymorphum
and pellicatum.
Lat. 5°46.7S. and Long. 134°0' E. Depth 1788 m. Bottom: bluish green mud
of a uniform appearance, three species of Scalpellum were taken, viz. Sc.
moluccanum, chitinosum and inflatum.
Lat. 0° 32'S. and Long. 119° 39.8 E. Depth 655 m. Bottom: fine grey mud, two
species of Scalpellum were taken, viz. Sc. proclive and deforme.
Lat. 4°20 S. and Long. 122°58'E. Depth 75—94 m. Bottom: sand with dead
shells, two species of Scalpellum were taken, viz. Sc. rostratum and aries.
Lat. 5°39'S. and Long. 122°12' E. Depth 1886 m. Bottom: solid green mud,
two species of Scalpellum were taken, viz. Sc. distinctum and elegans.

ei)
at Stat. 227, Lat. 4°50'.5S. and Long. 127°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. caliatum and formosum.
at Stat. 241, Lat. 4°24'.3S. and Long. 129°49'.3 E. Depth 1570 m. Bottom: dark sand with
small stones, two species of Scalpellum were taken, viz. Sc. formosum and
sessile.
and at Stat. 295, Lat. 10°35'..6S. and Long. 124°11'.7 E. Depth 2050 m. 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 Sca/fel/um at 32 of these, and, while only one species was taken
at 20 of these Stations,

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 Scalpel/um-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 Gruvet’s list of 1904
the number of species of the genus Sca/pe/lum would now be 125. In his Monograph Gruvet
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 Gruvet, 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. Stearns? Pilsbry and
with Sc. polymorphun 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

SIBOGA-EXPEDITIE XXXI@. 8

Darwin's Sc. villosum, like Se. trispinosum collected by the “Challenger” and like Sc. podlicc-
pedoides taken by the ‘Siboga”, have a simply keeled, relatively short and nearly straight
carina, a sub-carina and a rostrum. The shape of the valves in these species, of the lower whorl
especially, is triangular with the umbo at the apex, i. e. at the extremity opposite to the peduncle.
Darwin said (in 1851), that Sc. v2llosum “leads on to Pollicipes’’; I think he would quite agree
now that we had better consider that species and those nearly related as derived from Pollicipes.
The form of the valves, their number, the occurrence of a sub-rostrum in Sc. vz/losum (as in
the no doubt nearly related Sc. calycudus Aurivillius) the occurrence of two extra valves of the
lower whorl in one of the specimens of Sc. pollictpedotdes, mihi (cf. the description of that
species 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
keeled, straight carina. I think we ought to divide them into three groups which I suppose
developed independently from the forms with straight carinae. Calling the place where the umbo
is situated in a species like Sc. v2d/osum its upper extremity, we see the carina lose its original,
straight form either by adding almost equally at both ends, in which case its shape becomes
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 my report of 1883, to create the division
distinguished by imperfectly calcified valves.

We would thus have the following four main divisions:

Al, 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
of 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. Aollicipedordes n. sp.,
Sc. aries n. sp. and Sc. acutum Hoek.

1 With regard to this valve I wish to point out the following difficulty; originally it always belongs to the valves of the
capitulum, but in several species it is overgrown or covered by the rostral lateral, the rostral margins of the right and left valves touching
one another in the medial line. Sometimes these margins are slightly hollowed out in the middle, in which case a narrow oval-shaped
area is seen at the place where the rostrum should be; in that case it is very difficult to decide whether a rostrum is present or not
without preparing and isolating the valves — and it is, of course, better not to do so in all those cases in which a species is represented
by only one specimen. The value of the rostrum for classification purposes is diminished by this circumstance.

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 and a sub-carina in several species. The little males have
a capitulum with valves and a peduncle, or rudimentary valves. [Sectio: Ea-Scalpellum|
Number of species of this group at present known: rr. It is represented
in the collection of the “Siboga” by four species: Sc. rostratum Darwin:
Se. Peront Gray; Sc. uncus n. sp.; Sc. Stearnsi Pilsbry, var.
C. Species in which the carina may 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. chiténosum n. sp.;
Sc. enflatum n. sp.; Sc. javanicum n. sp.; Sc. curtosum 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

Mavemuom valves = 2 2 se 2. ee. 8, 8 [SERtIO: Arca: Scalpellim|

To this group belong all the remaining species of Sca/pellum, about 8o. 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.

6. 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. sesseZe n. sp.; Sc. celiatum 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 hamatum G. O. Sars.

To this division belong about 36 of the known species of Sca/fellum, 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. tmbricatum n. sp.; Sc. crinitum n. sp.; Sc. humilen. sp.; Sc. pellicatum n. sp.

d. Carinal latus with the carinal margin divided into two parts, which meet at an obtuse angle
or are almost continuous with one another, the umbo being at the place where the two
parts meet. Upper part of the margin not, or only very indistinctly hollowed out.

Type: Scalpellum formosum n. sp.

To this division belong 17 of the known species of Scalpellum; it is represented in the
collection of the “Siboga’”’ by nine species: Sc. graczle n.sp.; Sc. proclive n.sp.; Sc. deforme n. sp.;
Sc. trapezoideum n. sp.; Sc. hexagonum n. sp.; Sc. praeceps n. sp.; Sc. elegans n. sp.; Sc.
sculptum n. sp.; Sc. formosune n. sp.

e. Carinal latus with the carinal margin not divided into two parts, straight or very slightly
hollowed out, with the umbo at the base, where the carinal margin meets with the basal
margin. The base of the carina touches, or nearly touches, the upper extremity of the peduncle.

Type: Scalpellum virgatum n. sp.

To this division belong 7 of the known species of Sca/sellum; of these four were collected

by H.M.S. ‘Siboga”, viz.: Sc. vwirgatum n. sp.; Sc. candidum n. sp.; Sc. fissum n. sp.;

Sc. tnucertum n. sp.

A. Sectio: Proto-Scalpellum
1. Scalpellum pollicipedoides n. sp. Pl. V, fig. g—11.

Valves fifteen, covered by thin and transparent 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 almost
parallel to each other. It is rather thick in the under half, flat 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 beyond 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
nearly equals the scutal margin. Near the apex the two terga slightly diverge from one another.

The carina is only very feebly bowed longitudinally and has the umbo at the apex
which in the largest specimen projects freely. The carina has no flat roof but is laterally bowed
and not very deeply keeled. The width increases from the apex to the base; the surface is not
smooth but feebly, transversely hollowed out at five places over its length.

The upper latus is small, of triangular shape, with the scutal margin strongly hollowed
60

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. Its 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 infra-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. Labrum
not very swollen, slightly elongated in a longitudinal direction; crest without distinct teeth;
palpi 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 toothed edge covered with very delicate hairs
placed in groups of two or three; inferior margin clothed with longer hairs.

Maxillae 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 8 pairs of spines. On the outer surface numerous groups of hairs (three or four in a group),
near the spine-bearing edge.

Outer maxillae 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 (sometimes even a fifth) pair much more delicate on

the front aspect. Dorsal tufts of three or four spines at the extremity of each segment.
61

Caudal appendages triangular, uni-articulate, small; a tuft of about half a dozen
delicate hairs at the extremity.

Penis, rather short, reaching to the extremity of the fifth segment of the last pair
of cirri; its basal part broad with only a few scattered hairs, the terminal part of about the
same length as the basal part, cylindrical, rather narrow, indistinctly ringed. It bears very
delicate hairs, which are irregularly distributed over the surface and a rather dense tuft of
hairs at the 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
shortest 0,28 mm. They contained larvae in the Nauplius-stage, some of the larvae had partly
shed off the exuviae.

The male of this species is a true complemental male. I found two of them in the
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 (4). The male is figured Pl, 5, fig. 11; its size is
0,35 mm. X 0,25 mm. It has six valves: two scuta, two terga, a carina and a rostrum, the
general shape of which can be seen from the figure. The scutum is the largest, the rostrum
is much broader than the carina. The tergum has 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. Peront and Sc. villosum as described by Darwin. But the males of the present species
have 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. vz/loswm and Sc. Peronz. It has very 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 species was collected during the cruise of H. M.S. ‘“Siboga”’ at:

Stat. 274. December 26, 1899. Lat. 5°28'.2S., Long. 134°53'..9 E. Depth 57 m. 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. tréspinosum 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
the capitulum is more like a normal Sca/pe//um in consequence. Like Sc. vzllosum and trispi-
nosum it comes near to Podlicipes, especially P. sertus and this is particularly the case with
regard to the shape of the valves of the lower whorl.

One of the specimens shows this relation in a still more conspicuous way and I have
62

described the discovery of that specimen as an interesting case of reversion in a short note
published by the Amsterdam Academy of Science’. 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, Pl. V* 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 additional valves is developed.) In fact, the
few small valves which according to Darwin were wanting in the lower whorl of Sc. o¢/loswm
to convert it into a Podlicipfes 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 Pollicifes and Scalpellum, but I
think the case shows clearly that a form with more numerous calcareous plates in its capitulum
(like Podlicepes) is the older, the form with fewer (like Sca/ped/um) the younger one; moreover
that the Scalpel/um-species with straight carinae, inhabitants of shallow water, must be considered
as the oldest, 1.e. the species most resembling the primitive form of Scalpellum.

Beescaulpellum aries m sp. Ply Vj; figs 12.

Valves thirteen. Carina straight. Scutum and tergum large. Upper latus narrow, nearly
reaching the peduncle. Valves of the lower whorl six: a large and prominent rostrum, two
small rostral latera of triangular shape, two narrow carinal Jatera 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
angle 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.

1K. Akademie v. Wetensch. te Amsterdam, Proceedings of the Section of Sciences, VII, 1905, p. go.
2 Of the present publication.
63

Sub-carina triangular, the umbo pointing outwards; laterally it slightly overlaps the
carinal latera. .

Rostrum strong and rather large, having the shape of a pyramidal wedge, with the
apex very prominent beyond the occludent margin of the scutum. Lateral margin nearly straight.

Latera of the lower whorl two pairs, small, corresponding probably with the rostral
and carinal latera of other species of Scalpel/um. The inferior angle of the pentagonal upper
latus 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.

Length of the capitulum 8 mm., of the peduncle about 2 mm.

The “Siboga’”’ collected this interesting form at:

Stat. 204. September 20, 1899. Lat. 4°20'S., Long. 122°58’E. Depth 75—94 m. 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 Sca/-
pellum villosum Leach, Sc. trispinosum mihi, Sc. sexcornutum Pilsbry and some of the species
provisionally described by Avrivitiius and which are all characterised by straight or nearly
straight carinae. In Sc. avdes the carina may really be said to be straight; it can be distinguished
easily from the other species by the number (13) of its valves and by the very characteristic

shape of its rostrum.

3. Scalpellum acutum Hoek. Pl. VII, fig. 1.
HoEK, Cirripedia collected by H. M.S. “Challenger”. 1883, p. 80, pl. III, fig. 19, pl. VII, fig. 12.

This interesting deep-sea species was collected by H. M.S. “Siboga” at three different
Stations. They are very small animals: I measured two, in one the total length 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”. GruveL* has described as a new species (Sc. longirostrum) a form of Scad-
pellum much resembling my Sc. acutum, the main difference being that the carina of the new
species is somewhat broader. My figure (“Challenger’’ Cirripedia Pl. II, fig. 19) represents the
little animal 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
wanting, only slightly developed in the superior part’’ has been misleading in so far that I
should have added: a little more so towards the inferior extremity. Of the other differences
GRUVEL points out, the height of the sub-carina, which he says nearly equals that of the rostrum
(“presque aussi élevée que le rostre’’) and which is much smaller in the “Challenger” specimens
as also in those collected by the “‘Siboga’’, is by far the most important. But altogether these
differences are only slight: in comparing the specimens with one another they may perhaps
prove after all to be identical.

1 GruveL, A., Cirrhipédes du “Travailleur” et du “Talisman”. 1902, p. 7o.

At the end of the description of Sc. dongirostrum, Gruvet in his “Monographie”’ (1. c.
p. 58) says that the dwarf males also differ. It is true that I named Svc. acutum as one of the
species whose males have no 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 | figure one of them on PI. VII,
in fig. 1. Comparing this figure with that given by Gruvet for the male of Sc. longirostrum,
the main difference is the absence of a peduncle in Gruvet’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. Gruvet’s specimen, but I think it is possible... ..

I consider this species, like Sc. sguamuliferum Weltner and Sc. striatum Aurivillius, as
belonging to the group of Proto-Scalpellums. The carinae of these species are not quite straight
but they are only little bowed and (with the exception of that of Sc. sgwamuliferum) 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. 1°58'.5 N., Long. 125°0'.5 E. Depth 1264—1165 m. Bottom:
stone. 2 specimens.

Stat. 151. August 12, 1899. Lat. 0° 12'.6S., Long. 129°48’ E. Depth 845 m. Bottom: fine grey
mud with coarse particles. I specimen.

Stat. 211. September 25, 1899. Lat. 5°40°.7S., Long. 120°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. /ougirostrum 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. Scalpellum rostratum Darwin. Pl. V, fig. 13.
DARWIN, Monograph of the Sub-class Cirripedia. The Lepadidae, 1851, p. 259, pl. 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@. 9

I have nothing to add to Darwin's excellent description of this species, neither for the
hermaphrodite form nor for the complemental males. Darwin discovered that the latter were
attached in this species to the integument of the hermaphrodite, in a central line, between the
labrum and the adductor scutorum muscle, three individuals in a group. Opening the capitulum
of one of the “Siboga” specimens I found the little males at once at the place indicated by
Darwin, the only difference being that I found not three but four of them attached to the
hermaphrodite. The size and form of the complemental male and of its rudimentary valves
(carina and scutum) are in the main as described by Darwin. The largest specimen measured
0,91 mm. (according to Darwin its length is “/,9.) of an inch = 0,89 mm.). The scutum is
narrow; it is considerably smaller than that in Darwin's figure, but it has exactly the size (0,2 mm.)
which it should have according to Darwin's description. The whole of the sac, which represents
a combination of capitulum and peduncle, is covered with very minute hairs. Beneath the
rudimentary carina and down the peduncular part of the sac are planted numerous much longer
spines which to a large extent are bifid at the extremity. The fig. 13 of Pl. 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 36 m.). The ‘Siboga”’ collected it at the following places:

Stat. 47. April 8—12, 1899. Bay of Bima (North Coast of Sumbawa). Depth 13—55 m.
Numerous specimens.

Stat. 204. September 20, 1899. Lat. 4°20'S., Long. 122°58' E. Depth 75-94 m. Bottom: sand
with dead shells. 2 specimens.

Stat. 213. Sept. 26—Oct. 26, 1899. Saleyer anchorage and Surroundings. Depth down to 36 m.
Bottom: coral reefs, mud and mud with sand. 6 specimens.

Stat. 294. January 23, 1900. Lat. 10°12’.2S., Long. 124°27’.3 E. Depth 73 m. Bottom: soft
mud with very fine sand. 6 specimens.

5. Scalpellum Peroni (Gray). Pl. V, fig. 14, 144, 148.

Smilium Peronii J. E. Gray, Annals of Philos. New series, X, 1825.
Scalpellum Peronii Darwin, Monograph. Lepadidae, 1851, p. 264, pl. VI, fig. 6.

I refer to this species the specimens of Scadpel/um 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 investigated by Darwin, which had a total length of little more
than one inch (25,4 mm.) and the capitulum of which measured about three quarters of an inch
(19 mm.). Perhaps the differences between the description and figure given by Darwin and the
specimens 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
covering the valves and the interspaces are by no means so strong and so dense as they are

represented in the figure given by Darwin; and secondly, that the rostrum and the subcarina,
66

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 knew 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. [GruvEeL’, found three specimens of Sc. Peronz 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. Scalpellum uncus n. sp. Pl. V, fig. 15; Pl. VII, fig. 2,

ioe)

Valves thirteen. Carina angularly bent with the umbo in the middle of its length.
Rostrum rather large. Three pairs of latera. Upper latus pentagonal. Sub-carina pyramidal,
standing out beyond the surface of the carina.

Of this species there are three specimens representing two different forms.

The capitulum is flat, broad in the middle, the upper part slightly produced. It has
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 47°).

Scutum middle-sized, with the upper end pointed; nearly quite flat; lateral margin
nearly 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.

Tergum 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.

' GruveL, A., Révision des Cirrhipedes. Nouvell. Archiv. d. Muséum. (IV). IV, 1903, p. 234.

Carinal latus elongated pentagonal, narrow, with the umbo about in the centrum
of the surface, slightly projecting outwards.

Sub-carina small; solid, pyramidal, standing out beyond the surface of the carina.

Peduncle about half the length of the capitulum, rather narrow, narrowest about the
middle of its length; surface with minute chitinous scales standing at some distance from one
another. In one of the membrane-covered specimens of Station 47> the length of the peduncle
is more than half the length of the capitulum. °

Size. Length of the capitulum 9,1 mm., of the whole animal 13 mm. in the specimen
from Station 285; in the largest specimen from Station 47> the corresponding dimensions are
9 and 13,8 mm.

Complemental males. Two complemental males were observed in one of the
specimens from Station 47> attached to the surface of that part of the sac or mantle of the
hermaphrodite animal which unites the inferior halves of the two scuta. These males are relatively
large, the longest diameter of the body being 0,9 mm. Their shape is elongated oval and the
body 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 Pl. VII has been drawn
from the male of this species; it has a great resemblance to the male of Sc. Peron? and, no
doubt, that of several other shallow-water species.

This species was collected by H. M.S. “Siboga” at two Stations, viz. at:

Stat. 47". April 12, 1899. Entrance to Bay of Bima (Sumbawa). Depth 296 m. Bottom: fine
sand with mud (coral). Two specimens. One of them was attached to a small
stick, to which a piece of coral was also attached.

Stat. 285. January 18, 1900. Lat. 8°39..1 S., Long. 127°4'.4 E. Depth 34 m. On the limit between
mud and coral, Lithothamnion. (Anchorage south-coast of Timor). One specimen.

Observations. The present species comes nearest to Sc. Peron of the known species,
e.g. in the number of valves, the shape of the carina and the form (not the size) of the tergum.
It differs from it by the absence of the fine spines which cover the membrane in Sc. Peronz,
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 (Pl. VI, Fig. 2) without a distinct
membrane as being different from the specimens from Station 47» (PI. V, fig. 15), 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, I became convinced, however, that there was no
reason to consider them as specifically distinct. It is true that they were taken at very different
depths; but other species also range over depths of rather great difference. Thus, for example,
Sc. vulgare Leach observed in very shallow water and also at a depth of 97 m. For this
species GruveL* has described a very characteristic case of polymorphism, corresponding in many
regards to what I found in Sc. wszcws, viz. that specimens of different localities |? and depths]
show differences in the development of the membrane covering the valves, of the interspaces

separating the valves, as also in the grade of calcification, the hairiness of the membrane etc.

1 GRUVEL, A., Révision des Cirrhipédes. Nouvelles Archives du Muséum. (IV). IV, 1903, p. 234.
68

69
7. Scalpellum Stearnst Pilsbry var. robusta and var. gemina n. var. Pl. VI, fig, I—12.

Scalpellum Stearnsi Pilsbry is a shallow-water species from Japan. It was described for
the first time (1890) by Pirssry' and a year later by Fiscuer? (as Sc. cadcariferum). Both
WELTNER (I. c. p. 250) and Grover (l.c. p. 44) consider the species of FiscHer as synonymous
with that of Prmspry, and comparing the figures there can be no doubt that they are right.

In the Malay Archipelago H. M.S. “Siboga” collected at different Stations and at depths
varying from 204—450 m., specimens of a Sca/pe//um-species, which at first sight showed great
resemblance with Pirssry’s Sc. Stearnsz. I have been long in doubt, whether they belong to
that species or not. The result of a careful comparison of the specimens of the Malay Archipelago
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 Pinspry’s species.

I give in fig. 1, Pl. VI, a figure of Pirspry’s Sc. Stearns from a specimen collected by
LiscHKE near Nagasaki which belongs to the collections of the Berlin Museum of Natural
History *. It was in dry condition but it corresponded in all regards with the descriptions and
figures given by Pirssry and Fiscner. The varieties vodusta and gemina differ from the Japan

species in several regards as will be shown.

a. Scalpellum Stearnst, var. robusta, Pl. VI, fig. 2, 3, 8—12.

The variety vodusta 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 voéwsta 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 vodusta 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

1 Pirspry, H. A., Description of a new Japanese Sca/pe//um. Proceed. Acad. Nat. Sci. Philadelphia. 1890, p.441—443. (Sc. Stearnsi).
2 FISCHER, P., Description dune nouvelle espéce de Sca/pel/um du Japon. Bullet. de la Soc. Zoolog de France. XVI, Heae:

p- 116—118. (Sc. erearupe:
3 The director of the Museum, Prof. Kart Mosius, and the Keeper of the Collection of Crustaceans, Dr. W. WELTNER, made

the study of these specimens easy and agreeable to me.

say; the specimens I have been able to investigate were in dried condition and did not show
this detail.

In the specimens of the variety vodusta, the chitinous membrane is developed very
strongly along 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
seems also a remarkable characteristic of this variety. All the known species of Scalpellum have
rather short peduncles, the longest I have seen being that of Sc. Darwénz mihi, which measures
*/"4s of the length of the capitulum. Of the three specimens of the variety rodwsta, one is
considerably smaller, most probably not full-grown (this specimen is figured Pl. VI, fig. 3; its
capitulum is 28,6 mm. long, its peduncle 20 mm.); the other two seem to be full-grown:

the length of the capitulum is 48 mm. 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.

Purssry and Fiscuer both give figures of this species representing specimens at their
natural size. Pitspry 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 Scadpellum;
Fiscuer’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 voéusta 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
specimen of the variety vodwsta also, but their number is there only 14.

There are in the ‘Siboga’”’ collection three specimens in all which I consider to belong
to this variety. They were caught at three different Stations, viz.

Stat. 5. March 10, 1899. Lat. 7°46'S.,. Long. 114° 30'.5 E. Depth 330 m. Bottom: mud.
Large specimen, figured Pl. VI, fig. 2.

Stat. 251. December 8, 1899. Lat. 5°28'.4S., Long. 132°0'.2 E. Depth 204 m. Bottom: hard
coral sand. Large specimen attached to a piece of shell, which bears numerous
tubes of tubicolous Annelids on its surface.

Stat. 254. December 10, 1899. Lat. 5°40'S., Long. 132°26'E. Depth 310 m. Bottom: fine,
grey mud. Small specimen, figured Pl. VI, fig. 3.

b. Scalpellum Stearnsi, var. gemina.

The variety geména has imperfectly calcified valves. In the Japan species and in the
variety robusta the valves with the exception of the marginal portions are perfectly calcified,
the calcified portion having the shape of the valve itself. In the variety gemzna the calcified

Ap!

portions of the scutum, tergum, upper latus, and infra-median 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 Pl. 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 needles 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. robusta. In the four specimens I was able to investigate, the dimensions were as follows:
Specimen 1. Length of capitulum 47'/, mm. Length of peduncle 60 mm. Number of rings on
peduncle + 48.

Specimen 2. Length of capitulum 49 mm. Length of peduncle 60'/, mm. Number of rings on
peduncle + 40.

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 48'/, 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 rodwsta, 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. 5°35 S., Long. 119° E. Depth 450m. Bottom: Globigerina ooze.
Four specimens: two couples of two.

In the descriptions of Pirspry and Fiscuer, 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 (Pl. VI, fig. 7).
73

79
i-

Maxillae with a long, sinuous edge and a great number of nearly equal spines. Those
at the upper corner are slightly larger and another group of the larger spines is planted at
one-fourth the height from the inferior angle. The apodeme is stout and not very long.

Outer maxillae are well-developed with the bristles of the nearly straight inner
margin divided into two separate tufts, separated from one another by a little excavation without
bristles. Exteriorly they are swollen and not very densely beset with bristles. The opening
leading into the body-cavity is large and situated on the top of a rounded protuberance.

Cirri. First pair short and very stout; rami not very unequal in length; much more
so in the number of segments, and especially in breadth (Pl. VI, fig. 6). The anterior segment
has nine, the posterior sixteen segments. The segments of the anterior ramus are oblong in
transverse direction and are only united with one another over part of the breadth; the segments
of the posterior ramus are as broad as they are long, with the exception of the first segment
which is longitudinally oblong. In both rami the segments bear numerous spines along their
margins, the outer segments over the whole surface.

Second-sixth cirrus differ from one another mainly in length; this difference is
greatest between the second and third cirrus. In the, second cirrus the anterior ramus is moreover
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.

Caudal 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 about half a dozen longer ones on the rounded apex.

Sex. The specimen investigated showed no trace of male genital organs: neither
testicula nor penis; I think this species must be considered as belonging to the group of
unisexual 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 females.

Males. At first I could not find the males of this species. At last I found them on the
large specimen of Station 5: very small bead-like individuals attached in great number to the
surface of that part of the sack or 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 touch
and even to flatten each other mutually. Fig. 9, Pl. 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
little conical papilla which projects beyond the surface of the remaining part of the sac. Round
the opening are four very small calcareous parts like so many rudimentary valves and between
these, small excrescences with short hairs, like minute tentacles, are planted. I 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. gemzna 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. Stroemz 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 Scalpedlums which
develop without a free-swimming Nauplius-stage cannot, from that discovery, be doubted. One
might suppose, that only the complemental-males (or the dwarf-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 Sca/-
pellum 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 Pl. 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. Scalpellum chitinosum n. sp. Pl. VII, fig. 4.

Valves thirteen, covered by chitinous membrane. Scutum and tergum imperfectly calcified.
Carina with the umbo at some distance 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 beyond 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 flat and very broad, the length being less than one and a half

73
SIBOGA-EXPEDITIE XXXIa@, 10

74
times the breadth. The occludent and carinal margins are both strongly convex. The whole
capitulum is covered by a chitinous membrane, with the exception only of the apex of the tergum.
The shape of the valves is mostly very indistinct: though the largest specimen of Station 45
has been figured the shape of the latera is much more distinct in the smaller specimen of the
same Station. Hence for the description of these valves the smaller specimen has been mostly
made use of.

The scutum has the occludent margin convex and the tergal margin slightly hollowed
out. The calcified part is formed of two segments united at the apex: the one (the occludent
segment) is broader at the base and narrower towards the upper extremity; the other (the
tergal segment) extends along the tergum, is very narrow and shows the same width over its
whole length.

The tergum 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 at the apex of
the valve. Along the occludent segment the chitinous covering forms a cushion-like investment,
the free margin of which is strongly 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. Its width increases distinctly, but not very strongly from the umbo
downwards; its margins develop into 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 to 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 valves
which is covered by chitinous membrane only: this is most probably the place for the rostrum
if it were present as a calcified valve.

The infra-median latus has the umbo near the base. Its general shape is that of
a tall wine-glass, almost without stalk, with a small and narrow foot and the upper part wide.

The carinal latus has the umbo at the base, 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 rows.

Size. The size of the largest specimen was 28 mm. total length and 21 mm. length of
the capitulum.

One of 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.

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

Mouth. Labrum not very bullate, triangular when seen from above; teeth hardly
distinguishable. Palpi rather elongate with a tuft of hairs at and near the extremity.

Mandibles 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.

Maxillae 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.

Caudal 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 8'* 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. javanitcum 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 trace 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. 7°24'S., Long. 118°15'.2 E. Depth 794 m. Bottom: fine grey
mud. Two specimens.

Observations. At Station 271, December 21, 1899; lat. 5°46’.7S., long. 134°0’E.;
depth 1788 m.; bottom green mud, a specimen of a Scadpel/um-species was collected (together
with three specimens of Sc. zzjflatum, 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.
Its 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

the roof of the carina is quite flat in this specimen, there being hardly a trace of the longitudinal
ridges which are distinct in the specimens of Station 45. This difference, however, is not considered
by me of sufficient importance to separate from one another forms which quite correspond in
other regards. Another difference is given by the two rostral latera which meet in this specimen
over the whole length of the rostral margins, a rounded space in the middle of this margin
only remaining uncovered by calcareous matter. A rostrum, however, could not be said to be

present in this specimen either.

9. Scalpellum inflatum n. sp. Pl. VII, fig. 5 and 5a.

Valves fourteen. Capitulum bulky, swollen, covered by a thick chitinous membrane.
Membranous interspaces between the valves. Umbo of the carina at some distance from the
apex, the valve angularly bent in consequence. Scutum and tergum imperfectly calcified and
not divided into two parts by a prominent ridge, their occludent margin strongly convex. Sides
of the carina broad; upper latus pentagonal; infra-median latus elongated with the umbo near
the base; carinal latus with the umbo near the base. Rostrum quite covered by membrane.

This species is represented by three specimens. It is without doubt nearly related to
Sc. compressum, mihi, collected by the *Challenger’’. Its bulkiness, the structure and imperfect
calcification of scutum and tergum distinguish it at once from the “Challenger” species. The
specimens were covered with mud; the outlines of the valves could only be made out after
cleaning 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 10 mm. in a specimen the capitulum of which measures
17,5 < 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 especially.
The chitinous interspace between the valves is particularly broad between the carina and the
other valves.

The outline of the scutum is quadrangular, it is strongly bowed in transverse direction.
The occludent margin is convex; where it reaches the tergum a recurved apex is formed which
overlaps a part of the tergum. The calcified part consists of an elongated occludent and a
short and narrow tergal segment.

The tergum is rather quadrangular than triangular. Its occludent margin is strongly
convex forming with the concave uppermost part of the carinal 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 of a broader occludent and a slightly narrower carinal segment.

The carina has the umbo at some distance from the apex and the part above the
umbo forming an angle with the part underneath it. A roof, slightly hollowed out longitudinally
and growing rather wide towards the base of the valve, can be distinguished from the sides

which are narrow at the base and of considerable width in the uppermost part.
76

Rostrum (fig. 5@) 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 rostral 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 rows: one rostral, one carinal and on both sides two lateral
rows. In the specimen figured there are about 9 scales in each longitudinal row.

Size. The specimen figured is the largest of the three. Its total length was 45 mm., that
of its capitulum 27 mm. One of the specimens was found attached 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 flat tubular projections.

The first cirrus has both branches short, broad, flattened; 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 caudal appendages have six segments, the last one is abruptly cut off in a
transverse direction and bears numerous hairs on the extremity.

No trace 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 formed 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. javantcum, Sc. curiosum ete.

738

H.M.S. “Siboga’’ collected this species at:

Stat. 271. December 21, 1899. Lat. 5°46.7S., Long. 134°0 E. Depth 1788 m. Bottom: bluish
green mud of uniform appearance.

Observations. This 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
characteristic of the ‘Challenger’ species and are imperfectly calcified. I think it possible,
however, that these differences may turn out to be of less importance than we now think, if
we only had a richer material at our disposal. Sc. compressum was collected in the Celebes Sea
at a depth of about 3900 m.

10. Scalpellum javanicum n. sp. Pl. VII, fig. 6, 6a and 7.

Valves thirteen, partly calcified, covered by chitinous membrane. Tergum strongly recurved.
Carina with the umbo at some distance from the apex and the part beneath the umbo very
feebly 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
different size, the largest of which has been figured. It is very nearly related to Sc. chztenosum,
and to Sc. japonicum, mihi, the latter collected by the “Challenger”. To the same group of
species belongs Sc. zzflatum. 1 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 capitulum 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-
quence 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. chztinosum.

The scutum much resembles the same valve of Sc. chztiznosum. The tergal segment
of the present species, however, is much shorter than in the other. The apex of the scutum
is slightly produced and forms a very delicate but distinct beak which reaches to the base of
the tergum. ;

The tergum has the calcified part V-shaped. Its occludent margin is very strongly
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. chztinosum.

The carina has the umbo at some distance from the apex: the relation of the length
of the part above the umbo to the whole carina being about 1 to 7. The 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 of the sides are narrow.

The upper latus would probably have a pentagonal shape if totally 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 lying at some distance from the apex. j

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 wine-glass
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 collected by H.M.S. “Siboga” has a total length of 35 mm.
the length of the capitulum being 22 mm.

I 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 (Pl. VII, fig. 7) is oval; it is rather large, the longest diameter being not quite 1 mm.,
the breadth about half the length. Its 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 trace 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. regzum, Sc. velutinum 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 lone spines attached to
them being visible but in quite a rudimentary condition.

This species was collected at:

Stat. 18. March 18, 1899. Lat. 7° 28'.2S., Long. 115° 24.6 E. Depth ro18 m. Bottom: fine grey
mud. Three specimens.
11. Scalpellum curtosum n. sp. Pl. VII, Fig. 8, 8a and 84.

Valves fourteen, imperfectly calcified, covered by a thin chitinous membrane. Calcified
79

part of the scutum with a lateral lobe along the tergal margin. Tergum V-shaped. Carina
simply bowed with the umbo ‘at a short distance from the apex. Upper latus irregularly penta-
gonal. Infra-median latus irregularly wine-glass-shaped. Rostrum small triangular.

This species is represented by a single specimen only. ‘

The capitulum has an elongate oval shape, sloping gradually into the peduncle. The
valves are separated by chitinous interspaces, their colour is not white but yellowish; they are
covered by a thin chitinous membrane. The occludent margins of scutum and tergum form
together a continuous arch; the apex of the capitulum is distinctly recurved.

The imperfectly calcified scutum consists of an elongate occludent segment, which is
broadest at the base and a narrow tergal segment.

The tergum consists of two segments of about the same width, the carinal segment
being much longer than the occludent segment. Apex pointed, distinctly recurved.

Carina simply bowed, for °*/;ts of its length with a flat roof bordered on each side by
a ridge. The remaining '/," is between the umbo and the apex of the valve and is not flat
but bowed laterally.

Upper latus irregularly pentagonal with the tergal margin longest and the umbo
pointing in the direction of the tergal segment of the scutum.

Of the valves of the lower whorl, the triangular rostrum (fig. 8a) is by far the
smallest, the carinal latus the largest. The latter valve has the umbo at the outer angle
beneath 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 (Pl. VII, fig. 84).

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
together about 7 longitudinal rows. The scales are much nearer to one another in the upper
end than downwards.

Size. The total length of the specimen was 13,7 mm., that of the capitulum alone 8,7 mm,

The 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. 118°15’.2 E. Depth 794 m. Bottom: fine grey
mud, with some Radiolariae and Diatomeae.

Observation. At the same Station 3 other species of Sca/pel/um were collected, viz.
Sc. polymorphum, Sc. chitinosum and Sc. crinitum.

12. Scalpellum polymorphum. P\. VII, fig. o—11.

Valves fourteen, covered by membrane, imperfectly calcified in some of the specimens.

Carina simply bowed, roof bordered on each side by a strongly developed ridge; umbo very
80

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. 11) 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 capitulum 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 Pl. 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 tergum is triangular. 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. 9a) 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

SIBOGA-EXPEDITIE XXXI@.

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 about the same length and meet at a very
obtuse angle. In the specimens with imperfectly calcified valves, the calcified part has the form
of a chinese boot, the part that is not calcified having the shape of a rectangular triangle.

The peduncle is cylindrical and shows 8 to 12 longitudinal rows of scales. In the
specimens with perfectly calcified valves these scales are perhaps distributed slightly more
regularly than in the others.

Size. The specimens figured measure 20, 1g and 26,6 mm.; their capitulums 13,3, 13,8
and 16,2 mm.

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

Mouth triangular when seen from above, slightly bullate. Labrum with hardly
distinguishable teeth; palpi conical, rather pointed at the extremity, with short and not
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 four triangular, small, sharp teeth. Teeth 2 and 3, and 3 and inferior
angle at shorter distances from 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 four. 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 first is the strongest, above the notch; one spine in the notch
and 7 to 8 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
extremity 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.

Cirri. 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.

Second cirrus with about 20 segments in each ramus: the first 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 ones 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
fused together and about 25 clearly distinguishable segments. These grow gradually longer and

narrower from the base to the extremity. Each segment bears, as a rule, 4 pairs of long spines
82

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 hirsute 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 bears a group of three very long, feathered hairs or spines at the extremity.

No penis.

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 Pl. 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. 7°24'S., Long. 118°15'.2E. Depth 794 m. Bottom: fine grey
mud. One almost perfectly, two imperfectly calcified specimens.

Stat. 256. December 11, 1899. Lat. 5°26.6S., Long. 132°32'.5 E. Depth 397 m. Bottom:
greyish green mud. One perfectly calcified specimen.

Affinities. This very interesting species is perhaps more closely allied to Sc. rutzlum
Darwin than the descriptions of the two species would at present lead us to suppose. It ‘is also

similar in several regards to Sc. d¢stinctum Hoek.

13. Scalpellum adestenctum Hoek. Pl. VII, fig. 12.
HOEK, Cirripedia collected by H. M.S. “Challenger”. 1883. p. 111, pl. 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 (Pl. 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.

The same is the case with the ridges along the roof of the carina: these ridges are
by no means so distinct in the *Siboga’’ specimens as in that of the “Challenger’’. I should
mention also that the scales of the peduncle which in the “Challenger” specimen are placed
in not very regular rows, in the largest “‘Siboga’’ specimen may be said to form longitudinal
rows; in the smaller specimen, however, this can hardly be said.

With regard to the shape of the carina I found that this species belongs also to the
Sectio C: the 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. folymorphum with which it corresponds also in
several other regards.

Finally I must point out, that the chitinous interspaces between the valves which were
rather broad in the ‘Challenger’ specimen, are much more prominent in the larger “Siboga”
specimen (from Station 175) than in the smaller (the one figured) which was taken at Station 208.

The structure of the animal of the only specimen taken by the ‘Challenger’’ was not
studied; I have thought it useful, therefore, to examine one of the “Siboga” specimens.

Mouth not very bullate; crest of the labrum with a row of very small knobs at the
place of the teeth; palpi 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 about 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 body cavity at the end of a long and flat 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 8 broad, the longer 10 more
cylindrical segments. The first 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.

Second cirrus (in the specimen investigated) both rami broken off at one side, and one
ramus broken off at the other side. The only remaining ramus has 17 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 very long, then come four
or five nearly quadrangular segments, the following nine growing longer and narrower, the
14‘ being the longest of all and nearly five times as long as broad. The last segments grow
still narrower but diminish in length: the last is very narrow and tapers towards the extremity,
where three short spines are planted. The number of pairs of spines found on the front side
of each segment is from three to seven; this number is largest at the 14‘ segment.

Caudal appendages long and narrow, tapering towards the extremity and consisting
of 5 (left side) or 6 (right side) segments, of which the penultimate is the longest. Near the

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 males. 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
‘34 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 trace
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 spine-like 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. 0° 34'6N., Long. 119°8'.5 E. Depth 1301 m. Bottom: fine,
grey mud. One specimen.

Stat. 175. Aug. 30, 1899. Lat. 2°37'.7S., Long. 130°33'.4 E. Depth 1914 m. Bottom: fine,
grey and green mud. One specimen, attached to the shell of a Gastropod.

Stat. 208. Sept. 22, 1899. Lat. 5°39'S., Long. 121° 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.

Observations. This species is nearly related to the foregoing: Sc. polymorphum.

The form of the scutum and of several other valves, however, show its distinctness.

D. Sectio: Arco-Scalpellum

14. Scalpellum moluccanum Hoek. PI. VII, fig. 13.
HOEK, Cirripedia collected by H.M.S. “Challenger”. 1883, p. 104; pl. V, figs. 3, 4.

H. M.S. “Siboga” collected one specimen of a Sca/fellum 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. zzflatum (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. regzum, 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
85

as belonging to that species. The description of the “Challenger” specimen was given from a
single specimen.

The valves of this specimen are to a large extent covered by chitinous membrane,
leaving (exactly as in the specimen of Sc. moluccanum, described in the “Challenger’’ report)
the apices of the valves uncovered. This membrane was moreover wanting on the left side of
the capitulum, at the places from which I had removed the other Scalpellums. Continuing to
take away this chitinous membrane I discovered that the area of each valve was distinctly
limited by a clear line and that 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 of each
valve. To decide whether Sc. regiwm and Sc. moluccanum are really different species, and also
to which the present specimen belongs, it would by all means be necessary to deal with the type
specimens as I have now done with the “Siboga” Scalpellum. Fig. 13 of Pl. VII represents that
specimen, seen from the left side after the chitinous covering was removed from the capitulum.

Whereas the “Challenger” took the species at Lat. 4°21’S. and at Long. 129°7’E.
from a depth of 1425 fathoms (about 2565 m.), H. M.S. “Siboga” collected it at:

Stat. 271. December 21, 1899. Lat. 5°46'S., Long. 134° 0’ E. Depth 1788 m. Bottom: bluish
green mud of a uniform appearance.

15. Scalpellum hamulus n. sp. Pl. VU, fig. 14 and 14a.

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. Umbo 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. The valves touch each other and are covered by a membrane which
is clothed with short hairs.

The scutum is very broad at the base, the lateral margin not beginning above the
apex of the infra-median latus (as is the rule in this genus) but 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 but rather sharp
and feebly recurved point.

The carina is simply bowed with a nearly flat roof widening very considerably from
the apex to the base. The roof 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

angle formed by the lateral margin of the scutum and the scutal margin of the tergum. The
86

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. 14a) is small, triangular, with the base directed towards the peduncle.
Its 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 */;"ts 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 11, 1899. Lat. 5°26'.6S., Long. 132° 32.5 E. Depth 397 m. Bottom:
greyish green mud.

Observation. This species is no doubt nearly related to the Atlantic species Sc.
velutenum 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.

16. Scalpellum diota n. sp. Pl. VII, fig. 15 and 15a.

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 larger valves etc.

Scutum quadrilateral, not quite twice as long as broad. Occludent margin nearly
straight, lateral margin convex, apex produced, pointed, slightly overlapping the tergum.

Tergum large, 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 flat, rather narrow.
87

Upper latus triangular with the umbo at the apex, this part acuminated fitting into
the angle between the scutum and the tergum. Lateral margin concave, carino-lateral margin
strongly convex and divided into two unequal parts by the recurved apex of the carinal latus.

Rostrum (fig.15@) very small, 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. Umbo at the apex.

Carinal latus with the umbo at the strongly recurved apex. The carinal margin is
convex, the upper lateral margin hollowed out.

Peduncle short, flat cylindrical, only */,"¢ of the length of the capitulum. Scales rather
large, placed in five longitudinal rows.

Size. The total length of the specimen is 10 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'.4S., Long. 132°0'.2 E. Depth 204 m. Bottom: hard

coral sand.
Observations. This species is nearly related to Sc. hamulus as also to Sc. rubrum
Hoek which was taken by the “Challenger” near Luzon, at a depth of 180 to 207 m. There
are however small differences in the shape of the valves, of the rostrum especially, as also in
the size and number of the scales of the peduncle. The description of Sc. rudrum was also

given from a single specimen; its capitulum measured only 5 mm.

17. Scalpellum sessile n. sp. Pl. VII, fig. 16.

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 membrane covers the valves. Whereas the valves of the lower whorl are
large, 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 out
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.
Roof and sides are not separated by ridges, the dorsal surface of the valve being laterally bowed.

The upper latus is trapeziform. There is a short but distinct carinal margin, the
length of which is about one fourth that of the scutal margin. The scutal and basal margins
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 infra-median latus is triangular, with a well-developed basal margin and the
umbo at the apex. Its rostral margin is slightly hollowed out, its carinal margin slightly convex.

The carinal latus is very large and has an irregular pentagonal shape. Its 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.

Size. The specimen figured Pl. 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:

Mouth seen from above triangular, with the part directed forward rounded and bullate.
Labrum with a row of small but distinct teeth; palpi conical with a tuft of spines at the
tip and a row of half a dozen shorter spines or hairs along the outer margin.

Mandibles 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. da/anozdes 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
groups, 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'—5'h) not very elongated with nearly equal rami of 16

2
SIBOGA-EXPEDITIE XXXI da. 12

segments. Several segments have only two pairs of spines at the anterior margin: one pair
very long near the extremity and a second shorter pair about the middle of its length.

Caudal appendages very minute, one-jointed with a few spines near the extremity
and a short and feeble claw-like spine at the tip.

No penis.

The eggs formed a single cluster in the specimen I opened; they had a much more
elongated shape than in several other species of Scadpeldum. They measured 0,47 X 0,27 mm.,
their number being 17.

This specimen was furnished with a dwarf male at one side only. The latter was attached
to the inner surface of the scutum near the occludent margin. Its shape was pear-like, the
peduncular pole being considerably the narrower. It showed no trace of valves. The prehensile
antennae were inserted very near the peduncular extremity. Its size was 0,5 X 0,3 mm.

The “Siboga”’ collected this interesting little species at:

Stat. 241. December 1, 1899. Lat. 4° 24'.3S., Long. 129°49.3 E. Depth 1570 m. Bottom: dark
sand with small stones.

Observation. This species is very nearly related to Sc. dalanozdes Hoek collected
during the cruise of the “Challenger” at Lat. 5°42°S., and Long. 132°25 E. at a depth of
129 fathoms, about 230 m. The latter species has about the same size and lives attached to
the arms of Metacrinus Murrayt. Sc. sessile differs from it, 1° by the trapezoid not triangular
form of its upper latus; 2° by the greater breadth of its infra-median latus; 3° by the form of
its carinal latus, which in Sc. éalanozdes 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. sesstle than it is in Sc. dalanozdes. Perhaps on closer examination of the ‘Challenger’ form at

least some of these differences might turn out to be not so important as I must consider them now.

18. Scalpellum ciliatum n. sp. Pl. 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 produced.

The uppermost (umbonic) parts 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 of the scutum
and its apex is not produced. The carinal and basal margins form together an arch.

9°

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 peduncle 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° 50.5 S., Long. 127°59' E. Depth 2081 m. Bottom: grey
mud with an upper layer of brown, both mixed with sand. One specimen.

Observation. This species is, most probably, nearly related to Sv. hérsutum 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. Aérsutum has a capitulum
of 6 mm. and Sc. czlzatum 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. Pl. VII, fig. 18, 18a@ and to.

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 capitulum 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,

the sides are best developed in the under part of the valve; the angle the roof forms with
the side is greater than go’.

The upper latus is quadrangular and rather large. The angle formed by the scutal
and basal margins is truncated. The umbo is near the angle the scutal margin forms with the
tergal. The carinal margin is the shortest.

The rostrum is triangular with the apex directed to the base of the scuta. There is
a narrow but distinct chitinous interspace between the rostrum and the rostral margins of the
rostral latera.

The rostral latus is broad but very low; the scutal margin runs parallel to the
basal margin, the short lateral and rostral margins are both convex.

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 convex.

The carinal latus is pentagonal, the carinal margin being divided into two parts.
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 laterally compressed and conical in the upper part. It is covered
with a hairy 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 27 mm. The total length
was about 40 mm.

According to the label the larger specimen of 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 species.

Labrum 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 on
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 3 and the inferior angle. Surface of the exterior part with numerous
delicate hairs, placed in groups of two or three.

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.

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 maxillae 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 on each segment near the extremity.

Sixth cirrus long, slender, 28—209 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 5
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 (Pl. 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 < 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. 5°11'.2N., Long. 119°35'.4 E. Depth 450 m. (chart). Bottom:
apparently sand and stone.

Stat. 256. December 11, 1899. Lat. 5°26'.6S., Long. 132°32’.5 E. Depth 397 m. Bottom:
greyish green mud.

Observation. In the smaller specimens the breadth of the capitulum at the base is
about the same as at the height of the upper latus. In these the carinal margin of the tergum
is not so distinctly divided into two parts, the apex of the carina does not project freely and
the umbo of the carinal latus is not seated at the tip of a triangle which projects beyond the
line of the carina. As I feel convinced that these smaller specimens, some of which were
attached to the larger, belong to this species, I am inclined to admit that several of these
differences 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 to Sc. soczadzle Annandale! from Bali Straits, depth
160 fathoms = 310 m. The characteristic figure ANNANDALE gives of the group of specimens
of his new species is perhaps not quite so useful for recognizing an individual specimen. As
there also occur differences between his description of the valves, of the appendages, mouth-
parts etc. and 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.

20. Scalpellum imbricatum n. sp. Pl. VIII, fig. 15 and 15a.

Valves 14. Surface of valves covered by a slightly villous chitinous membrane. Carina
very large, nearly reaching to the apex of the tergum, simply bowed, roof furrowed longitudinally.
Rostrum narrow, indistinct. Infra-median latus narrow, with the umbo at the apex. Carinal latus
with the umbo 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
nearly reaching to the apex of the scutum. The surface is covered by a thin slightly villous
membrane which makes it difficult at first sight to distinguish the margins of the valves. There
are slight interspaces 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 occludent margin nearly quite straight. The apex is
bluntly pointed and hardly produced.

The carina is very large, nearly reaching to the tip of the tergum. It has a very
pronounced curvature. It has well developed sides and a roof that increases in breadth though
not very much from the 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.15@) is narrow, slightly increasing in breadth downwards, fitting

exactly between the rostral margins of the rostral latera, more or less concealed by membrane.

1 ANNANDALE, N.
pl. VIII, fig. 2.

, Malaysian Barnacles in the Indian Museum. Memoirs of the Asiatic Society of Bengal. I, 5, 1905, p. 77,

The rostral latus is quadrilateral, with the lateral margin considerably longer than
the rostral margin.

The infra-median 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. Its carinal margin is distinctly hollowed out.

The peduncle is nearly cylindrical; its length is nearly */,'¢s of the length of the
capitulum. Its surface is covered with small rounded scales, partly covering one another, each
scale being rounded and slightly swollen at the free extremity.

Size. 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. 132°0.2 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. pellicatum mihi and

Sc. soctabile Annandale.

21. Scalpellum crinitum n. sp. Pl. VIL, fig. 1 and ra.

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. Its occludent margin is convex, its apex rounded and not
produced in the specimen figured, rather sharp, though hardly 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 good 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.

It is broader near the base, very narrow in the upper part. It is not covered by the lateral
parts of the rostral latera.

The rostral latus is of an irregular shape, its basal margin being short and going
over imperceptibly into the lateral margin which is convex. The scutal margin is slightly hollowed
out, the angle it describes with the lateral margin truncated.

The infra-median latus is triangular with the rostral margin slightly hollowed out
and the carinal margin convex. The umbo is at the apex which is distinctly bent forward.

The 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 umbo
distinctly convex. The basal margin is short, the lateral margin feebly hollowed out. The upper
margin forms a sharp angle with the upper part of the carinal margin. That part of the latter
where the umbo is situated can hardly be 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 after a good deal of the feltlike membrane with the
calcareous algae and the muddy particles attached to them has been 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 five scales forming
such a row.

Size. Length of the whole animal 11,25 mm., of the capitulum 8 mm.

The specimens of this species were found attached to cylindrical black sticks of four 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
given the following results.

Body narrow, elongated, legs relatively stout.

Mouth with the labrum slightly bullate, edge with a long 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 of three or more.

Maxillae with a distinct notch beneath the group of upper spines, which consists of
one very stout spine, one rather stout and one or two much more delicate. Beneath the notch, in
which only some very 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.

Second maxillae bulky; outer surface rounded covered by numerous long hairs,
forming a tuft at the upper extremity. The opening giving entrance to the body cavity is at
the 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
interspace. Branches of the first pair of unequal length, the shorter is slightly broader and has
seven, the 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

Bi7)
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 trace 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 trace 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. 7°24'S., Long. 118° 15.2 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. zzsigne mihi from the Atlantic; it
can be distinguished from that species at first sight, however, 1° by the shape and condition
of the tergum, which is V-shaped in Sc. zusigne, 2° by the presence of a rostrum, which is

wanting in Sc. zzszgne and 3° by the form of the carina.

22. Scalpellum humile n. sp. Pl. VIII, Bion 2 and 24%

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 bordered 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 capitulum 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 scutum is large; its occludent margin is straight in the under and distinctly convex
jn 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.

SIBOGA-EXPEDITIE XXXIa. 13

The carina is simply and not very strongly bowed; umbo at the apex. Roof flat
not increasing much in width from the upper to the lower extremity, bordered by distinct ridges.
Sides of about the same width over the whole length of the carina.

The upper latus has six margins, the scutal margin being divided into two parts,
one rather short and straight the other larger and hollowed out. The umbo is at the angle
where these two lateral margins meet. The tergal margin is straight, also the short carinal
margin. The lateral margin is divided into two parts: a larger which is hollowed out and
separates the valve from the carinal latus and a much shorter part between it and the infra-
median latus.

The rostrum (fig. 2a) is an extremely small valve situated in the corner where the
two scuta and the two rostral latera meet.

The rostral latus is irregularly quadrangular; the rostral and lateral margins are
both convex, the second is longer than the first.

The 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 beyond 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. It 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 9 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:

Stat. 211. September 25, 1899. Lat. 5°40.75S., Long. 120°45'.5 E. Depth 1158 m. Bottom:
coarse 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. distiénctum has, moreover, no rostrum etc. From Sc. candidum n. sp. to which it

is similar in other regards it can easily be distinguished by the shape of its carinal latus.

23. Scalpellum arcuatum n. sp. Pl. 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

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 tergum 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 length.

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. 3@) 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-median 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 length 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. 10°35'.6S., Long. 124°11.7 E. 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. 1 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. avcuatum than
in Sc. gracile.

100
24. Scalpellum poculum n. sp. Pl. VIL, fig. 4 and 4a.

Valves 14 not covered by membrane. Carina simply bowed with a flat roof, bordered
by distinct ridges. Upper latus pentagonal with the umbo at the apex; apex produced. Rostrum
narrow, slightly broader at the upper extremity. Infra-median latus irregularly wine-glass shaped,
with the umbo near the base. Carinal latus with the umbo not far from the base. Peduncle
very short.

This species is represented by one specimen only.

The capitulum is flat, broadest about the middle of the scutum, slightly narrower
towards the base, distinctly pointed towards the upper extremity. The carina is not strongly
bowed, so that the whole capitulum looks as if slightly recurved. No membrane covers the valves.

The scutum has the ordinary shape; its occludent margin is strongly arched. It is
about twice as long as broad. The apex is slightly produced and overlaps the tergum.

The tergum is rather large; the occludent margin is nearly straight, the scutal margin
also straight, the carinal margin slightly convex beneath and slightly concave above the middle.
The apex of the carina presses very slightly into the carinal margin of the tergum. Apex
hardly produced, Growth lines visible, but not very distinct.

The carina has a distinct roof and well-developed sides. The roof grows broader from
the apex to the base, the sides are broadest in the upper part. The umbo is at the apex. The
roof is flat, bordered by 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
valve more distinctly than on any of the others,

The rostrum (fig. 4a) 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. Its 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 has 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 afterwards 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 regular 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
cover the whole surface and are much pressed together.

Size, The total length of the specimen is 6,6 mm., that of the capitulum 5,3 mm.

The “Siboga”’ collected the single specimen at:

Stat. 300. January 30, 1900. Lat. 10°48'.6S., Long. 123°23.1 E. Depth 918 m, Bottom: fine
grey mud,

Observation. This curious deep-sea species may be easily distinguished from the

Ioo

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. Pl. VII, 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. Its carinal margin
is convex and shows a trace of an angular excrescence above the point where the apex of the
carina touches the carinal margin. About '/,'¢ 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. Its 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 g longitudinal rows.

Size. The total length of the specimen is 18,6 mm., that of its capitulum 14,5 mm.

Iot

The single specimen was collected at:

Stat. 221. November 4, 1899. Lat. 6°24'S., Long. 124°39' E. Depth 2798 m. Bottom: solid,
bluish grey mud with Foraminiferae.

Observation. This species is no doubt nearly related to Sc. trapezotdeum n. sp. and
to Sc. truncatum Hoek. Under Sc. trapezotdeum 1 give the reasons why I think it better to
consider them as three different species. Scalpellum truncatum Hoek was collected by the
“Challenger” (a single specimen also) at a depth of 2520 m., 12°8°S.L. and 145° 10° E.L. and
therefore may also be considered as an inhabitant of the Indian Archipelago.

26. Scalpellum trapezoideum n. sp. Pl. VIII, fig. 6.

Valves thirteen not covered by membrane. Tergum with the occludent margin straight
and the carinal margin distinctly divided into two 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 the 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 less 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
occludent 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. déscolor, 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 80° 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 ‘/,'" 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 formed, 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 rostral latus is quadrilateral with the upper and basal margins of about the
same length.

The infra-median latus is narrow; its shape is that of an irregular hour-glass, the

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103

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 peduncle 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 spectmen was collected at:

Stat. 214. October 27, 1899. Lat. 6°30'S., Long. 121°55’E. Depth 2796 m. Bottom: grey
and green mud.

Observation. This species is nearly related to Sc. déscolor 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. trapezocdeum 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 proclive n. sp. Pl. VIII, fig. 7a.

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. Its occludent margin is nearly straight; it meets the carinal
margin 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 1/," 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

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tergal and scutal margins meet. The scutal margin is feebly hollowed out. The short basal
margin separates this valve from the infra-median latus, the other, longer basal margin separates
the upper latus from the carinal latus.

The rostral latus is quadrilateral; its rostral and lateral margins are longer than its
upper and basal margins.

The infra-median latus has the umbo below the centre. The lower part of the
valve is narrow and small, the upper part 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 of the carina. The remaining and
larger part of the carinal margin is very slightly hollowed out for the reception of the carina.

The peduncle is cylindrical. Its length is about '/,¢ that of the capitulum, its width
is about 1/; its length. It is covered with distinct, rather large scales of regular form, arranged
in six longitudinal rows. The number of scales in each longitudinal row is about 18.

Size. The total length of the specimen representing this species is 9,1 mm., that of
the capitulum 6,8 mm.

It was found along with Sc. deforme attached to the same small stem of a Tubularian at:

Stat. 87. June 19, 1899. Lat. 0° 32'S., Long. 119° 39.8 E. Depth 655 m. Bottom: fine grey mud.

28. Scalpellum deforme n. sp. Pl. VIII, fig. 74.

Valves thirteen. Surface covered with a hairy membrane, the margins of the valves not
distinct in consequence. Carina simply but very feebly bowed, laterally convex, roof and sides
not separated by ridges. Valves of the 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,
less than twice 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 feltlike 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 not very 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 '/4 the length of the
carinal margin of the tergum from the apex of 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
longer than the basal margin. The apex is slightly produced; the umbo is at the apex.

The rostral latus is rather broad, but not high. The upper and basal margins are

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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. Its length is only a little greater than
its width and is less than '/,"¢ 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. Aroclive attached to the same small stem of a
Tubularian at:

Stat. 87. June 19, 1899. Lat. 0° 32’S., Long. 119° 39.8 E. Depth 655 m. Bottom: fine, grey mud.

Observation. This species belongs to the same group of species or subdivision of
the genus as Sc. prochive, 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. Scalpellum gracile n. sp. Pl. VIII, fig. 8.

o
Ss:

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 flat 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

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106

narrow and is bordered by ridges which are not prominent. The sides are also narrow, only
slightly increasing in width from below upwards.

The upper latus is large with the apex produced, entering into the narrow angle
between the lateral margin of the scutum and the scutal margin of the tergum. The shape of
the valve is triangular, one of the angles is, however, truncated by the short carinal margin,
and another, the basal, by the very short basal margin between this valve and the rostral
latus. The umbo is at a little distance from the 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 infra-median latus is narrow and elongate with the umbo at the superior
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 part for the reception of the lower extremity
of the carina. The umbo is at a short distance from the base. The lateral margin is straight,
the upper margin slightly convex.

The peduncle is nearly cylindrical, compressed laterally. The scales are thin and
broad and rather prominent. They are placed in five longitudinal rows, each row having
about fifteen.

Size. The whole length of the largest specimen was 13,6 mm., that of its capitulum
10 mm. The size 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 front 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 between
the tips of the first 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.

Outer 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 of 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 be distinguished with difficulty; the longer ramus
has g much narrower segments, the first of which is very long. The shape of the shorter ramus
as a whole is leaf-like, that of the longer cylindrical. Both rami are covered with numerous
and long spine-like hairs.

Second pair elongate, also with unequal rami: the shorter has 12, the longer ramus
16 segments. In both rami the first 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

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and narrow. The segments bear numerous spines all over the surface and also 3 to 5 pairs of
longer ones along the anterior margin.

hte cirri of the’ 374 to 6 pair have extremely elongate and narrow rami. Those
of the 6' pair have rami of about 23 segments, which are all long and narrow but of which
the middle ones (from the 8't—18th) 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 trace 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 yolk of these eggs was composed of rather large spherical globules.

I observed two small males, 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, 1899. Lat. 5°40..7S., Long. 120°45’.5 E. Depth 1158 m. Bottom: coarse
grey mud.

Observation. This species is nearly related to Sc. odeswm; the form of the capitulum
as a whole and the greater height of the valves of the lower whorl, together with the different
shape of the peduncle and its scales make it necessary to consider them as different species.
The present species also shows affinity to Sc. zzcertum and to Sc. arcuatum, which, however,

are both species with a rostrum.

30. Scalpellum elegans n. sp. Pl. 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-developed, 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.

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108

The capitulum is elongate, twice as long as broad, rather flat. Its occludent margin
is nearly straight, its carinal margin strongly arched. The apex of the tergum is pointed. The
surface of the valves is here and there, especially at the occludent side, covered with membrane,
bearing short hairs. There is a distinct chitinous interspace between the carina and the other
valves. The valves of the lower whorl are strongly developed; the upper margin of the carinal
latus is the prolongation of the same margin of the rostral latus.

The scutum is quadrilateral, about twice as long as broad. Its lateral and occludent
margins are parallel and nearly straight. Where the occludent and tergal margins meet the
slightly 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
apex pointed, but hardly produced.

The carina is strongly bowed, with the umbo at the apex. It has a flat roof bordered
by ridges and increasing in width, but not very considerably, from the apex downwards. The
sides of 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,
its scutal 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 not
touch one another and as an extremely narrow streak of probably calcareous matter is seen
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 of a spiral, the dwelling-place probably
of a tubicolous annelid.

The specimen was collected by H. M.S. “Siboga” at:

Stat. 208. September 22, 1899. Lat. 5°39'S., Long. 122°12’ E. Depth 1886 m. Bottom: solid

green mud.
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109

Observation. This species has some resemblance to Sc. vz¢reum 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. Pl. VIII, fig. ro.

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 umrbo at the apex. Carinal latus pentagonal, with the umbo above the
middle of the carinal margin.

This pretty species is represented by one specimen only.

Its 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
of the lower whorl are strongly developed.

The scutum 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 90° with the roof.
They are distinctly furrowed in this part.

The upper latus is trapeziform 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. 10a) 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.

1909

I1O

The umbo of the carinal latus does not project beyond the line of the carina. The right and
left carinal latera meet over the whole length of the lower part of the carinal margin.

The peduncle is very short and completely covered by rather large scales, forming
six longitudinal rows. About six scales are present in each row.

Size. The total length of the specimen representing this species is 7,6 mm., the capitulum
alone measuring 6,2 mm.

The specimen was taken by H. M.S. “Siboga” at:

Stat. 221. November 4, 1899. Lat. 6°24'S., Long. 124°39 E. Depth 2798 m. Bottom: solid
bluish grey mud with Foraminifera.

Observation. This species shows some resemblance to Sc. vztrewm dredged by the
“Challenger” near Yeddo from a depth of 1875 fathoms (about 3375 m.). The general habitus,
the sculpture of the surface of the valves, the structure of the carina and the large size of the
valves of the lower whorl are nearly equal in both species. But in Sc. vztreum no rostrum was
observed; 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. scadptum. Under similar circumstances (bottom mud, depth + 3000 m.), from perhaps
similar ancestors, two forms have developed, the distinctness of which can not be doubted
though their resemblance is equally striking.

32. Scalpellum formosum n. sp. Pl. VIII, fig. 11 and 11a.

Valves fourteen, not or but very indistinctly covered by membrane, beautifully striated.
Tergum with the apex produced and pointed. Carina simply bowed, with the umbo at the apex,
with a flat roof 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 fine 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
convex 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.

IIo

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. 11a) is elongate, narrow. 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. Its 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
longitudinal 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°50.5 S., Long. 127°59' E. Depth 2081 m. Bottom: grey
mud with an upper layer of brown mud, both mixed with sand.

Stat. 241. December 1, 1899. Lat. 4° 24.3 S., Long. 129°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 Scadpellum vitreum collected

by the “Challenger” off Yeddo.

33. Scalpellum hexagonum n. sp. Pl. 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
large, elongate hexagonal. Rostral latus small; infra-median latus narrow 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.

IIt

Li2

The capitulum is elongate, about twice as long as broad, flat. It is not covered by
membrane and the lines of growth of the different valves are not very distinct. Though the
carina is not strongly bowed, the carinal side of the capitulum is more strongly convex than
the rostral or occludent side. There is no rostrum, hence the total number of the valves is
thirteen. The scutum and the upper latus are of considerable size and very peculiar shape.

The scutum is large; in consequence of the shortness of the basal margin the shape
of the scutum is almost triangular. The occludent margin is straight, only feebly convex in the
upper part. The tergal margin is rather long; it forms a small slightly recurved apex with the
occludent margin. The lateral margin has a depressed angle slightly above the middle of its length.

The tergum is medium-sized. Its occludent margin is convex; its carinal margin slightly
convex 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 pointed.

The carina is rather long, reaching to */,®s of the length of the carinal margin of the
tergum. 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
be seen 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
nearly equal parts at an angle with one another. The upper part is hollowed out for the
reception 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 of 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. Labrum 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
near and at the tip.

Mandibles with three equally distant teeth and the distance between the third teeth
and the pectinated inferior angle very short.

Maxillae with a distinct notch about the middle of the edge; with four spines, two of

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a a

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.

Outer maxillae 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.

Caudal 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
long and delicate hairs are planted at the end of the third and fourth segments, half a dozen
at the tip of the 5'® segment.

No penis. Animal unisexual. The specimen I investigated was furnished with a cluster of
eggs, altogether 20 in number, soldered together and attached with two threadlike ‘ovigerous
frena” to the inner surface of the mantle or sac. The size of the eggs was: 0,43 X 0,3 mm.
Their shape was oval.

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 & 0,4 mm.
I observed the prehensile antennae attached to the sac at a short distance from the peduncular
pole. No trace 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, 1899. Lat. 6°24'S., Long. 124°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 Sc. déstinctum Hoek and Sc. humile n. sp.; in other regards (more elongate form

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SIROGA-EXPEDITIE XXXI @. 15

114

of its upper latus, smallness and shape of its infra-median latus, form of the carinal latus etc.)
the present species is, however, so different, that it can be distinguished from the above-named

species at first sight.

34. Scalpellum praeceps n. sp. Pl. VIII, fig. 13.

Valves fourteen, covered by a velvety membrane; margins of valves not everywhere to
be distinguished. Carina with the umbo at the apex, simply and strongly bowed, with a flat
roof bordered by ridges. A 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 not far from the base, at 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 by a chitinous membrane which has a villous or velvety
appearance. The little hairs are especially conspicuous along the free 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 (fraeceps) 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 scutum has the 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 by 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
very blunt angle. The basal margin can hardly be distinguished as a special margin.

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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 peduncle is cylindrical, rather stout and short: about 1/,% the length of the capi-
tulum. Its 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. 0°59.1 S., Long. 129°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. s¢rzatum is: “trés net, triangulaire, allongé’’.

35. Scalpellum incertum n. sp. Pl. VIII, fig. 14 and 14a.

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
triangular, 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.

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The rostrum is hardly visible, being covered on both sides by the margins of the
rostral latera. The rostral margins of the two rostral latera do not touch, so that a narrow
strip of the small rostrum remains uncovered.

The rostral latus is quadrangular with the angle formed by the lateral and scutal
margins truncated. Its basal margin is much shorter than the scutal margin.

The infra-median latus is triangular, very narrow, with the umbo at the apex.
The apex does not quite reach to the truncated angle of the upper latus.

The carinal latus is quadrangular, with the carinal margin only very slightly hollowed
out, with the upper margin straight and the basal margin slightly shorter than the lateral margin.
The umbo is very close to the lower extremity of the carinal margin and does not project
beyond the line of the carina.

The peduncle is short, cylindrical but laterally compressed. The scales on the surface
are narrow, horizontally extended and at some distance from one another. They are arranged
in seven longitudinal rows: three on each side and one on the carinal side of the peduncle.
There are about 8 scales in each longitudinal row in the largest specimen.

Size. The total length of the largest specimen was 11 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 were collected) by HMMS: “Sibowar ate

Stat. 161. August 17, 1899. Lat. 1°10'.5S., Long. 130°9'E. Depth 798 m. Bottom: muddy
sand. 2 specimens.

Observation. This species has a great resemblance to various other species, for
example, to Sc. graczle n. sp. It differs from it by the shape of the upper latus and of the
carinal latus, as also by the presence of a rudimentary rostrum of which no trace could be found
in Sc. gracile. But for the shape of the carinal latus it would be considered as belonging to
the same group of species as Sc. formosum, Sc. truncatum (which have a rostrum) and as

Sc. tenue, Sc. proclive and Sc. deforme (species without a rostrum).

36. Scalpellum fissum n. sp. Pl. 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 occludent margin convex, in the smaller
specimens even more strongly bowed than the carinal margin. Apex of the tergum recurved.
Valves of the lower whorl well-developed.

The scutum is quadrilateral with the occludent margin convex. The tergal margin is

also convex in the larger specimens; in the smaller it is nearly straight. The lateral margin is
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convex in the under part, where it forms a continuous curvature with the basal margin. It is
hollowed out in the lower part where the apex of the upper latus borders upon it.

The tergum 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 truncated, 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. Its 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.

Size. 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 measuring 6,5 mm.

The specimens are attached to small stems 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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118

Palpi short, broad at the base, conical; a tuft of bristles at the apex, a few short hairs on
the interior margin.

Mandibles with three teeth and the inferior angle pectinated; tooth 1 and 2 twice as
far from one another as tooth 2 and 3; distance between 3 and inferior angle still smaller.
Surface of 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 of 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 or eight spines of nearly equal size. Surface near the edge covered
with hairs; superior margin furnished with a few hairs in the neighbourhood of the first spine,
inferior margin with a row of numerous hairs.

Outer maxillae have the inner surface rounded with numerous bristles, which can
hardly be said to be divided into two different groups; opening communicating with the body-
cavity at the end 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 quadrilateral, segments 9 and
following ones becoming more and more elongate, last segments very long and narrow. Each
segment has about four pairs of bristles along the anterior margin, a few hairs along the
posterior margin 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 6" 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.
They 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 trace 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
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1 ce)

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. 0° 23.8 N., Long. 127° 29’ E. Depth 472 m. Bottom: fine dark
muddy sand. One large and two smaller specimens.

Stat. 212. September 26, 1899. Lat. 5°54'.5 S., Long. 120° 19'.2 E. 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.

37. Scalpellum candidum n. sp. Pl. IX, fig. 3 and 3a.

Valves fourteen, not covered by membrane. Carina simply bowed with the umbo at the
apex; its roof flat, very broad, bordered by ridges. Upper 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. poculun.

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. pocelune.

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. poce/unz) 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.
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The scales of the peduncle are very distinct, at some distance from one another and
placed in 8 longitudinal rows. The length of the peduncle is about half the length of the capitulum.
Size. The total length of the animal is 7,8 mm., that of the capitulum 5,5 mm.

The “Siboga” took the specimen at:

Stat. 251. December 8, 1899. Lat. 5°28'.4 N., Long. 132°0'.2 E. Depth 204 m. Bottom: hard
coral sand.

38. Scalpellum virgatum n. sp. Pl. IX, fig. 4.

Valves thirteen covered with a 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
triangular incision near the upper extremity for the reception of the apex of the upper latus.
Valves of the lower whorl large. Infra-median latus wine-glass shaped with the umbo near the
base. Carinal latus quadrilateral with the umbo near the base.

This curious deep-sea species is represented by a single specimen only.

The capitulum is rather flat, little more than twice as long as broad, having the
carinal margin slightly more convex than the occludent margin. The apex of the tergum is
pointed and a little recurved. The surface is of a browny yellowish colour; scratching it with
a needle a very delicate skin or membrane loosens in little flocks from the surface. The ridges
of growth are very distinct on most of the valves; parallel furrows are visible on the scutum,
on the upper latus and also on the carinal latus near the base. The valves are separated from
each other by narrow, but distinct chitinous interspaces; that between the tergum and the upper
half of the carina being much broader than the others.

The scutum has a very characteristic shape. Its 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 of the upper latus fits exactly.

The tergum is triangular. Its 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 flat 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 tip 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
length, 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

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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 angle.

The peduncle 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.

Size. 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 bundle 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. 10°35'.6S., Long. 124°11'.7 E. Depth 2050 m. Bottom: fine
grey mud. 2
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. fissame,

Sc. candidum and Sc. incertum, 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 only’: P. mtedda (Lin.).
Like the other species, P. mz¢e//a 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. Darwzxz 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 metella Lin.

This is a very characteristic species and Darwin has given an excellent description of it.

Rumpnius 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 Pol/icipes occurs at a depth of even ro fathoms, and so far as I know this

still holds good.

1 GruveEL, Monographie p. 18, says that P. elegans Lesson occurs at Java, but he does not name the authority who observed
that species there — I hardly believe he is right.....
I21

SIBOGA-EXPEDITIE XXXI@.

T22

During the cruise of H. M.S. “Siboga” specimens of this species were collected on two
occasions :

At Station 51: Madura Bay in the southern part of Molo Strait; on the shore. About

20 specimens.
At Station 50: Bay of Badjo (West coast of Flores); on the shore.
N.B. As mentioned already p. 47 specimens of /6/a Cumingt Darwin were found attached

to several specimens of P. mztel/a at Station 51.

Genus Lithotrya Sowerby

Of this genus six species were known to Darwin in 1853 and only one new species
(L. pacifica Borradaile) has been added to this number in the 55 years since then. They are found
lodged in cavities, in calcareous rocks, shells, or corals and have been observed “generally”
within the tropics. All the species occur only in shallow water.

In the Malay Archipelago and in Australian waters, 4, perhaps 5, of the known species
have been observed: Z. cauta Darwin, New South Wales, Australia; Z. xzcoéarica Rhdt., Timor;
L. truncata Quoy et Gaimard, Philippines; Z. Aacéfica Borradaile, Funafuti. [Perhaps ZL. rhodtopus
J. E. Gray, the habitat of which was unknown to Darwin, belongs to the same region also;
the Copenhagen Museum possesses specimens labelled Z. rhodiopus J. E. Gray, Funafuti; they
are specimens purchased from the Museum Godefroy.

H. M.S. “Siboga” met with specimens of this genus on five different occasions; four

different species are represented in this collection.

1. Lethotrya nicobarica Rhdt.

REINHARDT (1850) has given the description of this species founded on specimens from
the Nicobar Islands. Darwrn (1851) when giving the description of this species in his Monograph
had RetnHarpt's paper at his disposal, but he could not compare the typical specimens used
by Retnuarpt. The specimens which Darwin identified with R.’s species were from Timor.

Through the courtesy of the Director, Prof. JuNGrRseN, and the Keeper of the collection
of Crustacea, Dr. Mertnert, of the Copenhagen Museum, I got free access to the specimens of
this species which are to be found in that Museum. They are — according to the label — from
Pulo Milu, Galatea. As Galatea Bay is the name of a Bay of the Island 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 great’. They correspond with Darwi’s-
description and figures in all essential regards.

Several forms collected during the cruise of H. M.S. ‘Siboga” belong doubtless to this
species. They are from two different Stations: from the reefs near Lucipara and from the
reefs of the Island of Kur, West of the Kei Islands. At both places, however, together

1 These had not been put aside as type-specimens, as is now the custom with specimens which have served for the institution
of “novae species”, so that Dr. Mrtnerr could not say with absolute certainty, that they were REINHARDT’s types.

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with, I might say, typical specimens of Z. nxécobarica, other specimens of a form or species of
Lithotrya were collected, which after careful study I feel inclined to consider as different
from Reruarpt’s L. nicobarica. 1 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
Darwiy's description brought to light that more or less interesting differences occur even between
the specimens which doubtless belong to the original species of Remuarprt, | think it useful to
enter into “some detail on that species first of all.

With regard to the valves of ZL. xicobarica the following may be pointed out:

The scutum 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

7
specimens, 5 in five, 6 in seven and 7 in two. In one of the specimens from Pulo Milu, Galatea,

scales of the peduncle, which the rostrum equals in width, varied from 4 to 7: it was 4 in four

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 Remynarpr a much greater number of zones is indicated.|

The latera which according to Darwin are unusually large in this species vary greatly
in the different specimens. Their general shape is as described by Darwi: 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

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spines distinct, sometimes it is hardly visible. In no case have I observed two large upper
spines. In the notch, or if it is absent at the place it occupies in other maxillae, three or four
very short and delicate hairs are planted. Next follows a slightly protuberant part with 5 or 6
pairs of spines and then a second smaller notch. Then about 8 pairs of spines and finally the
slightly prominent inferior angle with a brush of rather short spines.

The outer maxillae have a small but distinct notch between the upper and lower
group of spines.

Of the cirri the first pair is short; the general shape of the segments of this pair
is: narrow at 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 12 and 13 respectively. The segments are
thickly paved with bristles, which are themselves coarsely and doubly serrated.

The second cirrus has 17 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
of these basal segments and 15 upper segments with the usual structure.

The third cirrus has 22 and 24 segments: six and five of these are highly protuberant
and thickly clothed with spines.

The fourth cirrus has 23 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
segment 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 225°: Reef near Lucipara islands; 8—1o November 1899. 17 specimens.

Station 250: Reef near Kur island (to the W. of the Kei islands), December 6—7, 1899.
I specimen.

2. Lithotrya conica n. sp. Pl. IX, fig. 1o—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 has 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 the tergum, the tip of the carina not extending so high up. |

The scutum (PI. IX, fig. 11-4) is considerably larger than the tergum, its occludent
margin is bowed and long, its tergal margin is hollowed out, or (in the largest specimen)

124

125

straight. It is indistinctly beaked: the tip being rounded off as a rule. It overlaps the tergum
only very slightly.

The tergum (fig. 118) 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. Its 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 latus 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. 12). 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 Z. zzcodarica 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.: 12 and 7 to 8 respectively.

The maxillae 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 ZL. xécobarica, but the number of segments
is not inconsiderably smaller:

The left cirrus of the first pair has 9 and 11 segments in the slightly unequal rami;
the cirrus of the right side has 11 and 12 segments in the same specimen.

126

The second pair has 15 and 18 segments,
the third pair 17 and 20 segments,
the fourth pair 20 and 20 (21) segments,
the fifth pair 21 and 21 segments,
the sixth pair 22 and 22 segments.
The surface of the segments of the 4'"—6' cirrus is smooth or nearly so; the minute
comb-like scales, which make the surface hirsute in ZL. xzcobartca, are wanting in L. conzca.
The caudal appendages contain 18 segments in the specimen in which the sixth
cirrus had 22 segments in each ramus.
The penis is much like that of L. nzcobarica.

This species was collected at the following Stations during the expedition of H.MLS. *Siboga”:

Station 225°: Reef near Lucipara Islands; 8—1o0 November 1899. 8 specimens.
Station 250: Reef near Kur Island (to the West of the Kei Islands), December 6—7 1899.
3 specimens.

General Remark. At both places where specimens of ZL. nzcodarica were collected,
specimens of ZL. conica were also found. It cannot be made out, however, with the aid of the
preserved material, whether the specimens were really found at exactly the same place and
lived under absolutely similar circumstances, or not. The specimens of ZL. conzca are smaller
than most of Z. xzcodarica; some of the latter, however, are as small as most of the L. conzca,
yet show the differences in the shape of the capitulum and of the valves, which I think are
very striking. There is therefore no reason for 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.

3. Lithotrya pacifica Borradaile. Pl. IX, figs 13, 13@ and 14.

BORRADAILE, L. A., On some Crustaceans from the South Pacific. Part V. Proceedings of
the Zool. Soc. of London. 1900, p. 798, Pl. LI, figs 3, 3a.

On the east coast of Lombok two specimens of a Lzthotrya were collected which I
think belong to the species described for the first time by BorrapaiLe 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 Borrapatte. | consider it useful therefore to give a figure of the largest of the
Lombok specimens (fig. 13) 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 by scutum and latus shows a prominent longitudinal ridge with the zones
of growth running transversely and nearly straight. The latus is long and stout, its length

about */,"s the length of the tergum, its extremity being nearly on the same level with that of the
126

127,

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 with
4 (indistinctly 5) of the underlying scales.

The carina is very long and rather narrow, curved longitudinally and strongly bowed
laterally, hence very distinctly concave over its whole length. Its extremity stands off and
reaches higher up than that of the tergum. The middle row of knobs described by BorraDAILe
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. 132).

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 and 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 ZL. cauta 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 /é/a (? Cumznge 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 11 mm. A very small specimen of what I believe to be an A/epas (perhaps
identical with the A/efas Lithotryae 1 found attached to ZL. xzcobarica) occupies the corner

between the tergum and the carina where the rudimentary latus is to be looked for.

127

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PLATE I

Fig. 1. Poectlasma carinatum Hoek.
Fig. 1. Group of animals; magnified 3,25 diameters.

Fig. 2—4. Poecilasma dubium n. sp.
Fig. 2. Animal, lateral view; magnified 3,6 diameters.
Fig. 3. Carina, lateral view; magnified 11 diameters.
Fig. 3a.Carina, lower part, internal view; magnified 11 diameters.
Fig. 4. Maxilla; magnified 134 diameters.

Fig. 5—8. Poeczlasma excavatum n. sp.
Fig. 5. Animal, lateral view; magnified 4 diameters.
Fig. 6. Tergum; magnified 10 diameters.
Fig. 7. Carina, lateral view; magnified 8 diameters.
Fig. 7a. Carina, lower part, external view; magnified 8 diameters.
Fig. 8. Caudal appendages; magnified 36 diameters.

Fig. 9—10. Poectlasma excavatum, varietas.
Fig. go. Animal, lateral view; magnified 5,3 diameters.
Fig. 10. Apex of the scutum with the division of the tergum; magnified 36 diameters.

Fig. 11—22. Poectlasma obliquum n. sp.
Fig. 11. Animal seen from the right side; magnified 3,6 diameters.
Fig. 12. Animal from the left side; magnified 3,6 diameters.
Fig. 13. Scutum of the left side, interval view; magnified 3,6 diameters.
Fig. 14. Tergum of the right side, external view; magnified 36 diameters.
15a. Carina, lateral view; magnified 3,6 diameters.
156. Carina, internal view; magnified 3,6 diameters.
16. Labrum, seen from above; magnified 36 diameters.
. Teeth of the labrum; magnified 180 diameters.
17. Mandible; magnified 52,5 diameters.
18. Maxilla; magnified 52,5 diamaters.
Fig. 19. Outer maxilla; magnified 52,5 diameters.
Fig. 20. Left cirrus of the fifth pair; magnified 36 diameters.
1. Right cirrus of the fifth pair; magnified 36 diameters.
Fig. 22. Caudal appendages; magnified 36 diameters.

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x PP. Cc. Hoek, Cirripedia.

’ Fa, P. W. M. Trap, impr.
POECILASMA. 2

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Fig.

PLATE II

1—7. Dichelaspis Nierstraszi n. sp.

Fig.

Fig.
Fig.

Fig.

jie

Animal, lateral view; one of the large, hairy specimens collected at Station 258, Tual
Anchorage, Kei Islands; magnified 11 diameters.
Animal, lateral view, made transparent; magnified 11 diameters.

. Very young specimen; magnified 11 diameters.

and 36. Scutum and tergum of a young specimen; magnified 28 diameters.
and 44. Scutum and tergum of a full-grown specimen; magnified 28 diameters.
Carina, lateral view, of a full-grown specimen; magnified 11 diameters.

. Carina, lower part, internal view; magnified 11 diameters.

Mandible; magnified 180 diameters.
Maxilla; magnified 180 diameters.

Fig. 8—13. Dichelaspis Tydemani n. sp.

Fig.

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

I4—18.

Fig.
Fig.
Fig.
Fig.

Fig.

8.
9.
10.
Talis
12.

13.

Animal, lateral view, made transparent; magnified 34 diameters.
Scutum; magnified 63 diameters.

Tergum; magnified 63 diameters.

Carina, lower part, internal view; magnified 63 diameters.
Mandible; magnified 356 diameters.

Maxilla; magnified 356 diameters.

Dichelaspis orthogonia Darwin.

I4.
Tee
16.
Wye
18.

Animal, lateral view; magnified 10,3 diameters.

a. Scutum; 6. Tergum; c. Carina; magnified 10,5 diameters.

Termination of the carina, external view; magnified 28 diameters.

Maxilla; magnified 254 diameters.

A specimen of the same species from another Station; magnified 11 diameters.

- P. P. C. Hoek, Cirripedia.

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PLATE III

Fig. 1, 1A, 18 and 106. Dichelaspis orthogonia Darwin.
Fig. 1. a. Scutum; 6. Tergum; c. Carina; magnified 19 aemeeers!
Fig. 1A. Very young specimen; magnified 36 diameters.
Fig. 18. Young specimen; magnified 36 diameters.
Fig. 106. Carina from the interior; magnified 15 diameters.

Fig. 2—7. Dichelaspis Weberi n. sp.
Fig. 2. Animal, lateral view; magnified 6°/, diameters.

a 2
Fig. 3. a. Scutum; 4. Tergum; c. Carina; magnified 10 diameters.
Fig. 4. Carina, external view of the disc; magnified ro diameters.
Fig. 5. Mandible; magnified 134 diameters.

Fig. 6. Maxilla; magnified 134 diameters.

Fig. 7. Outer maxilla; magnified 52 diameters.

Fig. 8—13. Dichelaspis Versluysi n. sp.

Fig. 8. Animal, lateral view; magnified 11 diameters.

Fig. 9. a. Scutum; 4. Tergum; c. Carina; magnified 15 diameters.

Fig. 10a. cee from the interior; magnified 15 diameters.

Fig. 11. a. Mandible, magnified 63 diameters; 0. inferior angle of the
mandible of the right side; c. the same of the mandible of
the left side. 116 and c magnified 160 diameters.

Fig. 12. Maxilla; magnified 180 diameters.
Fig. 13. Caudal appendage; magnified 63 diameters.

Fig. 14. Dichelaspis Versluyst, varietas.

Fig. 14. Animal, lateral view; magnified 11 diameters.

a a

I. P. P. C. Horx,. Cirripedia.

Fa. P, W. M. Trap, impr.
DICHELASPIS.

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Fig.

PLATE IV

1—8. Megalasma lineatum n. sp.

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

ON Aun BW WY

Animal, lateral view; magnified 5 diameters.

Same, as seen from the carinal side; magnified 5 diameters.

Interior of a, scutum, 6 tergum and ¢ carina; magnified 5 diameters.

Carina, dorsal view; magnified 5 diameters.

Labrum; 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 (c.a.);
magnified 52,5 diameters.

g—12. Alepas morula n. sp.
Fig. g. Animal, lateral view; magnified 3,4 diameters.

Fig.

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10. Labrum; magnified 52,5 diameters.
11. Mandible; magnified 52,5 diameters.

. Ita. Inferior angle of the same; magnified 180 diameters.
12. Mawxilla; magnified 52,5 diameters.

. Alepas intermedia n. sp.

13. Animal, lateral view; magnified 3,6 diameters.
. 14. Labrum; magnified 52,5 diameters.
15. Mandible; magnified 52,5 diameters.
16. Maxilla; magnified 52,5 diameters.
. Alepas ovalis n. sp.
. 17. Animal, lateral view; magnified 3,3 diameters.
. 18. Animal, seen from the rostral side; magnified 4 diameters.

ig. 19. Alepas tenuis n. sp.

Fig. 19. Animal, lateral view; magnified 3,3 diameters.

20—22. [bla Sibogae n. sp.

gS.
>

20.

Animal, lateral view after the right half of the capitulum and the whole
body has been taken away. Two little males are seen in the mantle-
cavity; magnified 3 diameters.

Interior of the scutum A and the tergum 8; magnified 18 diameters.

Labrum with the mandible of the right side; magnified 52,5 diameters.

. Inferior angle of the mandible; magnified 254 diameters.

ries

XXI. P. P. C. Hoek, Cirripedia.

Fa, P. W. M. Trap, impr.
MEGALASMA — ALEPAS — IBLA.

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Fig.

PLATS

1—8. /bla Sibogae n. sp.

Fig. 1. Maxilla; magnified 180 diameters.

Fig. 2. Second maxilla; magnified 78 diameters.

Fig. 3. Male; magnified 36 diameters.

Fig. 4. Front part of the same male; magnified 78 diameters.

Fig. 5. Front part of another male, seen from the dorsal side; magnified 180 diameters.
Fig. 6. Labrum with palp and mandible zz sztu, of a male; magnified 180 diameters.
Fig. 7. Mandible of a male; magnified 440 diameters.

Fig. 8. Maxilla of a male; magnified 440 diameters.

g. g—I1. Scalpellum pollicipedoides n. sp.

Fig. 9. Animal seen from the left side; magnified 11 diameters.

Fig. 10. Another specimen; a, the two additional valves of the lower whorl; magnified
Ii diameters.

Fig. 11. Complemental male; a, antennae, c, carina, 7, rostrum, sc, scutum, ¢, tergum, 7, part
of the tergum, corresponding with the primary valve; magnified 180 diameters.

. 12. Scalpellum aries n. sp.

Fig. 12. Animal, lateral view; magnified 5,6 diameters.

13. Scalpellum rostratum Darwin.
Fig. 13. Complemental male; magnified 52,5 diameters.

. 14. Scalpellum Peroni (Gray).

Fig. 14. Animal, lateral view; magnified 2,8 diameters.
Fig. 14d, Sub-carina; 14, Rostrum.

. 15. Scalpellum uncus n. sp.

Fig. 15. Animal, lateral view; magnified 5,6 diameters.

P. P. C. Hoek, Cirripedia.

IBLA — SCALPELLUM.

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Fa, P. W. M. Trap, impr.

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PLATE VI

1. Scalpellum Stearnsi Pilsbry.
1. Animal seen from the left side; natural size.

Fig
Fig.
Fig
Fig.
Fig.

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o.
>

g. 2—3. Scalpellum Stearnsi Pilsbry, var. robusta n. var.

2. Animal seen from the left side (Station 5); natural size.

Idem (Station 254); magnified 1,1 diameters.

. 4—7. Scalpellum Stearnsi Pilsbry, var. gemina n. var.

Fig. 4. Two specimens attached to a sponge (Station 74); natural size.
Fig. 5. Valves, isolated; natural size.
Fig. 6. First cirrus; magnified 3'/, diameters.
Fig. 7. Edge of mandibles; magnified 18 diameters.
8—12. Scalpellum Stearnsi Pilsbry, var. robusta n. var.
Fig. 8. Male; magnified 78 diameters.
Fig. 9. Group of three males; magnified 52,5 diameters.
Fig. 10. Young animal creeping out of the Cypris-shell; magnified 78 diameters.
Fig. 11. Young animal, recently attached; magnified 36 diameters.
Fig. 12. Extremity of capitulum with the primary scutum and tentacles of the

young animal of fig. 11; magnified 168 diameters.
J Ss Ss §

xpeditie. XXXI. P. P. C. Hoex, Cirripedia.
| Er

g. 1, 2 et 4 G. S. Hoek, ceter P. P. C. Hoek del. Fa P. W. M. Trap, impr.
SCALPELLUM.

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15a.

18a.
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PLATE VII

Scalpellum acutum Hoek. Male, magnified 78 diameters.
uncus N. sp., magnified 5,6 diameters.

uncus n. sp. Male, magnified 52,5 diameters.
chitinosum Nn. sp., magnified 1,1 diameters.

wnflatum n. sp., magnified 1,1 diameters.

Se
SG
SG:
Se.
PAG:

se.

Se.

Sc
Gs
eS6:

SEs
PSG:
SYR
SES
Se:
Se.
SE
Se
SE
Se.
Sa
Sc.
Se
Se

mnflatum n. sp. View of rostrum, sketch. ¢. rostrum; 7./. rostral
latus; sc. scutum.

Ses

jJavanicum n. sp., magnified 1,1 diameters.
Javanicum n. sp. View of basis of carina, sketch.
javanicum n. sp. Male, magnified 52,5 diameters.
curtosum n. sp., magnified 5,6 diameters.

curtosune N. Sp.

curiosum N. Sp.

polymorphum
polymorphum
polymorphum
polymorphum

n.
n.
n.
n.

View of rostrum, sketch.

View of basis of carina, sketch.

sp. form A, magnified 3,2 diameters.
sp. form A. View of rostrum, sketch.
sp- form B, magnified 2,8 diameters.
sp. form C, magnified 2,8 diameters.

distinctum Hoek, magnified 3,2 diameters.
moluccanum Hoek, magnified 1,1 diameters.
hamulus n. sp., magnified 1,1 diameters.
hamulus n. sp. View of rostrum, sketch.
diota n. sp., magnified 5,6 diameters.

diota n. sp. View of rostrum, sketch.
Sessile n. sp., magnified 16,4 diameters.
ciliatum n. sp., magnified 15,5 diameters.
pellicatum n. sp., magnified 1,1 diameters.
pellicatum n. sp. View of rostrum, sketch.

pellicatum n. sp. Caudal appendage; magnified 52,5 diameters.

VIT

impr.

Fa. P. W. M. Trap,

SCALPELLUM.

HAY SPR A

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Alosowe. trinttitaty A SA the ‘8 eu VES
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. 14a.

15a.

PLATE VII

Scalpellum crinitum n. sp., magnified 5,6 diameters.

. Sc. crinitum n. sp. View of rostrum, sketch.

Sc. humile n. sp., magnified 5,6 diameters.

. Sc. humile n. sp. View of rostrum, sketch.

Sc. arcuatum n. sp., magnified 5,6 diameters.

. Sc. arcuatum n. sp. View of rostrum, sketch.

Sc. poculum n. sp., magnified 13 diameters.

. Sc. poculum n. sp. View of rostrum, sketch.

Sc. discolor n. sp., magnified 2,8 diameters.
Sc. trapezoideum n. sp., magnified 2,8 diameters.

_ Sc. proclive n. sp., magnified 5,6 diameters.
. Sc. deforme-n. sp., magnified 5,6 diameters.

Sc. gracile n. sp., magnified 5,6 diameters.
Sc. elegans n. sp., magnified 3,2 diameters.
Sc. sculptum n. sp., magnified 8,4 diameters.

. Sc. sculptum n. sp. View of rostrum, sketch.

Sc. formosum n. sp., magnified 5,6 diameters.

. Sc. formosum n. sp. View of rostrum, sketch.

Sc. hexagonum n. sp., magnified 8,4 diameters.
Sc. praeceps n. sp., magnified 4,4 diameters.
Sc. incertum n. sp., magnified 5,6 diameters.
Sc. incertum n. sp. View of rostrum, sketch.
Sc. imbricatum n. sp., magnified 4,4 diameters.
Sc. imbricatum n. sp. View of rostrum, sketch.

= N
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q Hy é
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4 :
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nN

la.

. P. P. C. Hoek, Cirriped

Hoek, del.

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papa aitt be shy Aut Epaals (Praia oh es | tere. Teg rs jaa.
*
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Pea eae. eG Salas hse sizty re bald: es

Steen Wik oth:

i a sii a. Sens Resean Shor
swerate tial 2a Doge GN. eae Ladd Leia Ay

Bit Me Tce oe pees ns mae da 42 ig eu ley .

ona Bie Vata stent why Fe eben eae

Rao ipRANE 5: boas pan |”

REM gt 2 trethteeth nye Ngo Tg,
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Hactht AG, obo d bvarsy, Viehelaeks-s
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iat ipuarer ‘ie wee

PLATE IX

1. Scalpellum fissum n. sp., with bowed carina, magnified 5,6 diameters.
Fig. 2. Sc. fissum n. sp., with straight carina, magnified 7,8 diametres.
Fig. 3. Sc. candidum n. sp., magnified 11 diameters.
Fig. 3a. Sc. candidum n. sp. View of rostrum, sketch.
Fig. 4. Sc. virgatum n. sp., magnified 5,6 diameters.
Fig. 5—8. Alepas lithotryae n. sp.
Fig. 5. Animal, lateral view; magnified 8,5 diameters.
Fig. 6. Mandible; magnified 80 diameters.
Fig. 7. Maxilla; magnified 180 diameters.
Fig. 8. Cirrus of 6th pair, caudal appendage, penis; magnified 52,5 diameters.
Fig. 8. One of the rings of the penis; magnified 254 diameters.

Fig. 9. Lithotrya nicobarica Reinhardt, magnified 1,5 diameters.

Fig. 10—12. Lithotrya conica n. sp.
Fig. ro. Animal, lateral view; magnified 1,5 diameters.
Fig. 11. Valves, magnified 5,5 diameters. A. Scutum; 4. Tergum; C. Carina.
Fig. 12. The scales of the peduncle immediately beneath the capitulum;
magnified 36 diameters.

Fig. 13, 13@ and 14. Lethotrya pacifica Borradaile.
’ Fig. 13. Animal, lateral view; magnified 5 diametres.
Fig. 13a. Rostrum; magnified 4,6 diameters.
Fig. 14. The scales of the peduncle immediately beneath the capitulum;
magnified 36 diameters.

Ka. P. W. M. Trap, impr. ~
SCALPELLUM—ALEPAS—LITHOTRYA.

PLATE X

. la—id. Poecilasma dubium n. sp. Four specimens with abnormal capitulum; magnified 10,5 diameters.
Fig.

2—5. Poecilasma fissum Darwin.
Fig. 2. Maxilla; magnified 78 diameters.
Fig. 2a. Clawlike spines at the upper angle of the maxilla, notch with the minute hairs; magnified
254 diameters.
Fig. 3. Second maxilla; magnified 78 diameters.
Fig. 4. Spines at the extremity of the 8th segment of the 6th cirrus; magnified 254 diameters.
Fig. 5. Pedicel of 6th cirrus, root of penis and caudal appendage; magnified 78 diameters.

6—7. Poecilasma eburneum Hinds.
Fig. 6. Second maxilla; magnified 78 diameters.
Fig. 7. Spines at the extremity of the 8th segment of the 6th cirrus; magnified 180 diameters.

. 8—16. Microlepas diademae n. sp.

Fig. 8. Capitulum attached to a spine of Diadema saxatile L.; magnified 3,6 diameters.
_ Fig. 9. Mandible; magnified 72 diameters.

Fig. 10. Maxilla; magnified 72 diameters.

Fig. 11. Second maxilla; magnified 72 diameters.

Fig. 12. Cirrus of the first pair; magnified 50 diameters.

Fig. 13. Cirrus of the second pair; magnified 50 diameters.

Fig. 14. Cirrus of the third pair; magnified 50 diameters.

Fig. 15. Cirri of the sixth pair and penis; magnified 50 diameters.
ig. 16. Two eggs with the nauplius-larvae developed; magnified 234 diameters.

Ka. PW. M. Trap, impr.
POECILASMA—MICROLEPAS,

| Seer sera 4 different, mais nous avons adopté comme base générale du prix de
feuille alam sans fig. flor. O.1 53 ae une feuille avec fig. flor. 0.20 a 0.25 ;

es d “souser: ption: es ‘

me
~

iS
‘ino tage
de ie { le poe des ‘monographies sera ea de 25 le

1¢

w
4

4 Déja paru:

Livr. (Monogr. LX) E. S. Barton. The genus Halimeda. With 4 plates.

> Livr. (Monogr. I) Max Weber. Introduction et cet de tae Avec Liste des

Stations et 2 cartes .

: Livr. (Monogr. II) G. F. eidehiant Deseiiplont of the ship an appliances sea for scieutihies

exploration. With 3 plates and illustrations.

e Livr. (Monogr. XLVII) H. F. Nierstrasz. The Salenogackes of the Siboga-Exp. With 6 pint
> Livr. (Monogr. XIII) J. Versluys. Die Gorgoniden der Si cae a

Te cepressiet h Mit 170 Figuren im Text.

> Livr. (Monogr. XVIa) A. Alcock. Rennes on the eacser Madreporaria of the: Siboga

Expedition. With 5 plates.

Livr. (Monogr. XY) CaPh; Sluiter. Die Sipunculden fe Echiuriden ae? Sibogt-Exp.
Mit 4 Tafeln und 3 Figuren im Text.

> Livr. (Monogr. Via) G. C. J. Vosmaer aay, H. AToraeut The Porifera of the ¢ Sibog

Expedition. I. The genus Placospongia. With 5 plates.

Livr. (Monogr. XI) Otto Maas. Die Scyphomedusen der Siboga-Expedition. “Mit 12 Tafeln.
Livr. (Monogr. XII) Fanny Moser. Die Ctenophoren der Siboga-Expedition. Mit 4 Tafeln.
Livr. (Monogr. XXXIV) P. Mayer. Die Caprellidae der Siboga-Expedition. Mit 10 Tafeln,
© Livr. (Monogr. III) G. F. Tydeman. Hydrographic results of the Bis 5 sonar With
24 charts and plans and 3 charts of depths ;

Livr. (Monogr. XLIII) J. C. H. de Meijere. Die Fchinoidea Hes Siboga: Exp. Mit 23 Tafeln,

Livr. (Monogr. XLVa) René Koehler. Ophiures de l'Expédition du sibaes
1¢ Partie. Ophiures de Mer profonde. Avec 36 Planches.
Livr. (Monogr. LII) J. J. Tesch. The Thecosomata and Grange. of ena _Siboge
Expedition. With 6 plates.
Livr. (Monogr. LVIa) C. Ph. Siuiter. Die Tuniéaten aa ‘Siboga-Expedition ©
. Abteilung. Die socialen und holosomen Ascidien. Mit 15 Tafeln .

Livr. Wee LXI) A. Weber—van Bosse and M. Foslie. The Corallinaceae of the Siboga-
Expedition. With 16 plates and 34 textfigures

Livr. (Monogr. VIII) Sydney J. Hickson and ee M. ‘England. The Stylsterina of
the Siboga Expedition. With 3 plates. .
Livr. (Monogr. XLVIII) H. F. Nierstrasz. Die Chitonen We Sibopa-Exph Mit 8 Tafeln.
Livr. (Monogr. XLV4) René Koehler. Ophiures de lExpédition du Sibeey
2¢ Partie. Ophiures littorales. Avec 18 Planches.
Livr. (Monogr. XXVIdés) Sidney F. Harmer. The Pterobranchia of the siboga-Expediton
with an account of other species. With 14 plates and 2 text-figures.
Livr. (Monogr. XXXVI) W. T. Calman. The Cumacea of the Siboga Expedition, With
2 plates and 4 text-figures :
Livr. (Monogr. LVIa) C. Ph. Sluiter. ‘Die Tuhicaten den Sitiova- Figpeditiva.
Supplement zu der I. Abteilung. Die socialen und holosomen Ascidien. Mit 1 Tafel.

Livr. (Monogr. L) Rud. Bergh. Die Opisthobranchiata der Siboga-Exped. Mit 20 Tafeln.

Livr. (Monogr. XIII a) J. Versluys. Die Gorgoniden der Siboga-Expedition.
II. Die Primnoidae. Mit 10 Tafeln, 178 Figuren im Text und einer Karte.

Livr. (Monogr. XXI) G. Herbert Fowler. The Cyc ae of the niboEs Expedition
With 3 plates and 6 charts . :

Livr. (Monogr. LI) J. J. Tesch. Die diem fotos aa Sibson: ‘papeastee: Mit 14 Tafeln.

> Livr. (Monogr. XXX) G. W. Miller. Die Ostracoden der Siboga-Exped. Mit 9 Tafeln.
> Livr. (Monogr. eA Pane Eilhard penis: Die enephyanuerse der ba aera gan

Mit 3 Tafeln .

Livr. (Monogr. LIV) Maria Boissevain: The Seaphopods of the ‘Siboga Expedition
With 6 plates and 39 textfigures .

> Livr. (Monogr. XXVI) J. W. Spengel. Studien fiber die Enteropneusten ae Siboga-Exp.

Mit 17 Tafeln und 20 Figuren im Text.

> Livr. (Monogr. XX) H. F. Nierstrasz. Die Newatanarahs Ba Siboga-Exp. Mit 3 Tafeln.
> Livr. (Monogr. XIIIc) Sydney J. Hickson und J. Versluys. Die Alcyoniden der Siboga-

Exped. I. Coralliida, I]. Pseudocladochonus Hicksoni. Mit 3 Tafeln und 16 Figurenim Text.

36¢ Livr. (Monogr. XXXIa) P. P. C. Hoek. The Cirripedia of the Siboga ewes

A. Cirripedia pedunculata. With 1o plates .

1 flor. = Mrk 1.70 = 1 sh, 8 d. = frs 2,12 en chiffres arrondies,

fp «gece - Monog
Fine complet _séparé

Livr. (Monogr. XLIV) C. Ph. Sluiter. Die Holothurien der Siboga-Expedition. Mit 10 Tafeln. f 6.— Mar 7-50

y Ye

HORS

» 12.75 —

wit

14:10
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