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Memoirs of the Indian Museum. 
[Voi.. II 
than the fourth. The fully developed rami of the posterior cirri armed like those 
of the first pair, except that on the greater number of the joints (all but the first few 
at the base) they bear only one transverse pair of bristles on each joint with a number 
of fine hairs between them ; hairs at the tip of the joints behind few and short. The 
posterior rami of the fifth and sixth cirri very fine, having 17 and 15 joints respec- 
tively, while the anterior rami have a very large number ; the hairs on the posterior 
rami short and extremely fine, confined to the tip of the distal joint (which is small and 
cylindrical) and to the distal end of the posterior margin of the last ten joints. Anal 
appendages very slender, consisting of about nine joints and extending slightly beyond 
the distal end of the pedicel of the sixth cirri ; the bunch of hairs at the tip short and 
sparse. Penis moderately long and slender, cylindrical, pointed at the tip, minutely 
annulated, bearing a few scattered hairs on the surface and a bunch of similar hairs 
at the tip. 
Mouth parts. — Mandibles not bullate, bearing a sparse row of minute, rounded, 
chitinous teeth. Maxillœ narrow ; the biting edge with a rather shallow incisure, at 
the base of which there is a small, conical projection ; the outermost spine by far 
the largest. Mandible with five teeth, the inner angle being dichotomous ; the outer 
tooth the largest, pectinate at its base on the inner margin, separated from the 
other teeth by a deep but not very broad incisure ; second, third and fourth teeth 
subequal, the innermost tooth very small ; second tooth pectinated at the base on 
the inner margin. 
Habitat. — Nicobar Islands, on floating wood {de Roepstorff). Ten specimens in 
rather bad condition. 
This species bears a close external resemblance to Gruvel’s figures of his Alepas 
indica from Singapore. It appears, however, to differ considerably from that species, 
with which I formerly confused it, in the structure of its cirri and mouth parts. The 
largest specimen I have seen measures 40 mm. in total length, but the peduncle in all 
is somewhat curved. 
Subfamily PŒCILASMATINÆ. 
Key to the Genera. 
1. Valves fully calcified, covering the whole or nearly the whole 
of the capitulum. 
(a) Carina not expanded laterally at the base 
(b) Carina expanded laterally at the base 
2. Valves more or less degenerate and separated from one 
another ; at least one calcified valve as a rule present. 
(a) Scutum split into two segments, which diverge from one 
another above, or reduced to a vertical linear rudiment . . 
Genus Pcecitasma, Darwin (1851). 
Lepadidæ with 3, 5 or 7 fully calcified, approximate valves. The scutum broad, 
entire or split into two vertical segments, of which the occludent segment 
Pœcilasma. 
Megalasma. 
Dichelaspis. 
