J2 CAPRELLIDA. 
Tus body of this animal is smooth. The head is 
round and unarmed. ‘The first segment of the body 
is very long, cylindrical, and slender. The second seg- 
ment is as long as the first, and resembles it, except 
that as the first gradually lessens in diameter pos- 
teriorly, the second as gradually increases posteriorly, 
and is armed inferiorly, in the ventral median line, with 
a long straight tooth, between the articulations of the 
second pair of arms. ‘These two segments, with the 
head, occupy half the length of the animal. The 
remaining five segments of the body are, therefore, 
shorter than in the majority of the species of this genus. 
The superior antenne are not half the length of the 
animal; the first joint of the peduncle is longer than 
the head; the second more than twice the length of the 
first ; the third about half the length of the second, and 
does not taper at the extremity: the flagellum is about 
half the length of the third joint of the peduncle, and 
half the diameter at the base. The inferior antennz are 
not half the length of the superior. The first pair of 
legs are very small, and situated at the extreme anterior 
limit of the first segment of the body, therefore close to 
the head. The second pair of legs articulate with the 
second segment near the posterior extremity, conse- 
quently are situated about the centre of the animal, a 
circumstance from which we presume that Say gave the 
animal its specific name; the hand is long, and some- 
what oval in its general form, but the palm, which is 
defined by a small tooth, is straight, running nearly 
parallel with the upper margin, and occupying about 
two-thirds the entire length of the hand, which is more 
than half the length of the second segment of the body ; 
the palm is armed at the anterior extremity with an 
acute tubercle or short tooth and a small denticle (which, 
