tg10.] N. ANNANDALE: Barnacles of the subgenus Smilium. 153 
The bathymetrical distribution is a wide one, ranging from a 
little over 100 fathoms to nearly I,900 fathoms. 
Specimens are most abundant on the glassy filamentous spi- 
cules by means of which sponges of the genus Hyalonema are 
anchored in the mud. They also occur, however, on the stems 
of Antipatharians and even on shells of living molluscs, e¢.g., on 
that of Xenophora pallida. ‘The species is markedly gregarious, a 
fact that may be due to the larve undergoing a considerable part 
of their metamorphosis in the egg. 
S. squamuliferuin is by far the commonest species of Pedun- 
culate in the deeper parts of the Bay of Bengal, and the speci- 
mens in the Indian Museum considerably outnumber those of all 
the other Indian Pollicipedide put together. In fact, the species 
is one of the few (so far as this family is concerned) of which it is 
possible to say that a satisfactory series exists in any museum. 
It is therefore unfortunate that it is one which does not, except in 
two particulars, exhibit any very marked tendency to variation 
and is apparently of limited geographical distribution. Two 
features in which its characters are the least constant are the 
length of the peduncle and the size of the subcarina. Compared 
with such species as S. laccadivicum, it may be described asa 
constant species. In the neighbourhood of Singapore and in the 
Gulf of Siam it is replaced by S. kampent, which, however, is a 
much less constant species and inhabits comparatively shallow 
water (30—50 fathoms). But S. rostratum, also a form that has 
not been found at great depths, replaces S. kampeni in the 
eastern parts of the Malay Archipelago; it appears to be a fairly 
constant species. 
Scalpellum (Smilium) bengalense, Annandale. 
Scalpellum bengalense, Annandale, Ann. Mag. Nat. Hist. (7) 
vol. xvii, p. 395 (1906), and Jllustr. Zool. ‘* Investigator,’ 
Crust. (Entom.), pl. 1, fig. 5 (1907) (young form). 
“~ 
Subsequent additions to the collection prove the type speci- 
mens of this species to have been immature. The adult herma- 
phrodite resembles S. squamuliferum very closely both as regards 
external structure and as regards anatomy, but may be recognized 
by the following characters :-— 
(1) The membrane covering the valves of the capitulum 
is transparent and of a yellowish colour. 
(2) The peduncular plates take the form, viewed from 
without, of small, transversely oval, flat bodies, and 
never surround the peduncle in complete rings or 
form ridges on its surface. 
(3) There are no ovigerous lamelle. 
(4) The peduncle is never much longer than the capitu- 
lum. 
