the Mouth in Sucking Crustacea. 11 
the clypeus and the base of the posterior antenne, so that the . 
small terminal joint projects between the antennee. Both pairs 
of maxille are small, completely covered by the large and flat . 
maxillipeds. The first pair of maxille exhibit only one 
narrow lobe (the middle lobe), which is armed at its apex with 
a few fine spines. The second pair of maxille have three 
small, narrow, and inarticulate lobules, of which the middle one 
and the external one or palpus are moveable. The cardo of 
the maxillipeds (fig. 2, px) is very large, transversely placed, 
and divided by membranaceous seams into several plates; the 
stem is small and short, but has a large foliaceous prolongation 
on the outer side, whereby the base of the stem becomes as 
broad as the anterior margin of the cardo, so as to produce the 
impression that the cardo here lies behind the stem, whereas 
it really lies, as usual, obliquely outside it; the short adnate 
lobes form in connexion with the stem a thick crest on the 
upperside, which is made to fit alongside a ridge, which on 
either side marks the outline of the broad sphenoid plate. 
This latter is at the base carinate and at the apex deeply bifid. 
The palpus is short, thick, biarticulate. . 
If, now, the clipping and tearing mouth and active appear- 
ance of Cirolane forcibly suggests the idea of a small shark, it 
is difficult to contemplate the Serolides without thinking of a 
little ray or skate. ‘That they live near the bottom is suffi- 
ciently evident from their broad, short, slightly vaulted general 
form, the crested and carinated dark-coloured back, the smooth 
white under surface, the sickle-shaped imbricate epimera, the flat 
broad head which is closely fitted into the first segment of the 
body, the salient eyes placed on the upper surface of the head, 
the position of the mouth on the under surface, and the limi- 
ted capability of swimming. Besides, their mandibles, though 
powertul,are not arranged either for clipping, grinding, or mas- 
ticating, but only for pinching or squeezing and biting through 
a hard surface; the maxillipeds cover up the other, very 
‘small, appendages of the mouth; and after them follow two 
airs of prehensile limbs of the same kind as those of Mantis, 
Xora, and Squilla. It cannot, therefore, be doubted that Sero- 
lides live upon prey, and that this consists of small rather slow 
animals living near the bottom, probably mostly such as have 
firm integuments. The hypothesis suggested by Milne-Edwards 
(Hist. Nat. des Crustacés, iii. 231), that they attach themselves 
to fishes, is contradicted by the very feature of their structure 
to which he refers in support of it. Their flat mouth would 
be powerless against the skin of a fish, even if the cup-like 
shape of the anterior parts of the body did not prevent the 
mouth from reaching the skin. Furthermore; the first pair of 
