1g10.]_ N. ANNANDALE: Barnacles of the subgenus Smilium. 147 
which often, if not always, differs in shape from that of the her- 
maphrodite. The alimentary canal is furnished with both a 
mouth and an anus, and is certainly functional. ‘These characters 
are better seen in the male of S. bengalense than in that of 
any other species with which I am acquainted, because the body 
of the male of this species, owing to the peculiar shape of the 
capitulum, can apparently be thrust out of the capitulum further 
than is usually the case without interfering with the relations of 
the different parts. An outline drawing of this form is therefore 
reproduced in text fig. 5. 
In one respect, however, the male of S. bengalense differs con- 
siderably from that of allied forms, namely, in the degeneracy or 
absence of the capitular valves, never more than four of which 
(two terga and two scuta) are present. In more typical species, 
such as S. squamuliferum, the shape and relative positions of the 
BIG =e squamuliferum, male, x 52. 
valves appear to be very constant and to afford sound diagnostic 
characters. The external shape of the capitulum and peduncle is 
also characteristic, 
In the less primitive species of the genus comprised in the 
subgenus Scalpellum, the male is far more degenerate. In exter- 
nal shape it is usually ovoid, with no trace of a peduncle. ‘There 
is rarely any trace of valves, but the whole surface is covered with 
minute hairs or spines as in the males of Smilium. At or near 
the end opposite to that by which the animal is attached to the 
capitulum of the female or the hermaphrodite—for in this sub- 
genus the larger individuals appear to be in the case of some spe- 
cies exclusively female—there is an aperture, which is usually 
circular in outline. From this aperture the generative products 
are given out and, at any rate in some cases, the tips of the cirri 
can be protruded. ‘The cirri, however, are much more degenerate 
