392 IDOTEIDA. 
being soldered in the middle with the large terminal 
joint, of which the posterior portion is subobliquely 
deflexed, with the extremity rounded, without any 
appearance of terminal or lateral points. The upper 
antennz consist of four short but very robust joints, an- 
gulated at the margins. The outer antennz are about 
one-fourth of the length of the entire animal, composed 
of a peduncle consisting of five robust joints, followed by 
a flagellum composed of three or four joints more or less 
closely soldered together. The legs are of nearly equal 
size, except the first, which is the largest; the coxe or 
epimeral portion of the second, third, and fourth pairs 
appear dorsally as very narrow marginal plates, but in 
the three posterior pairs they are much more developed 
and visible from above, forming the lateral margin 
of each joint, with the posterior angle produced into 
a sharp elongated point. The first pair of legs are the 
most robust, the third pair the longest, and the fourth 
pair the shortest. 
The animal is obscurely coloured, greyish-buff, with 
three longitudinal dusky lines, one down the middle of 
the back and the other two lateral. 
This species appears to us to be very closely allied to, 
if not identical with, the genus Cleantis of Dana (Expl. 
Exped. Crust. p. 707, pl. 46, f. 9; the type of which 
C. linearis was taken was from the stomach of a Silurus, 
in the Rio Negro, North Patagonia), the characters of 
which appear insufficient to warrant its separation from 
Idotea. 
We have obtained this species from Falmouth, taken 
by Mr. Barlee, and from Polperro, whence it was sent to 
us by Mr. Loughrin. 
The Hopeian Collection contains numerous dry speci- 
mens, to which the label “ Naples” ‘is attached; they 
