1374 



CRUSTACEA. 



The first pair of feet has the terminal part about as long as the 

 basal, and the furcation occupies one-third of its length. 



The second pair has for adhesion a very broad and flat surface 

 covered with scales, each scale terminating in a minute spine. The 

 animal was with difficulty detached from the fish, on account of its 

 attachment by these legs. The first pair of natatories was not ob- 

 served to have a branch. It consists of three joints. The second 

 rather slender, and a little longer than the first; the third much 

 shorter, and a little broader than the second, and terminating in a 

 few short setae. The second pair has a very short basal joint, the 

 second very stout and oblong, and this bears two two-jointed branches, 

 subequal in size, and furnished with very short setae. The third and 

 fourth pairs, have the basal portion thin and very large circular, with 

 two small appendages, corresponding to branches, on the posterior 

 margin, each with very short setae. 



Below, either side of last abdominal segment, there is a large sub- 

 triangular appendage, nearly fleshy in character; and also, just ante- 

 rior to same segment, there is a pair of small oblong prominences. 



The last abdominal segment is less than one-fifth the full breadth 

 of the abdomen. 



Subfamily SPECILLIGINJE. 



Genus SPECILLIGUS. 



Cephalothorax, abdomen, antennae, pedesque ac in Nogago. Cephalo- 

 thorax pone antennas lmas disco suctorio infra arrnatus. 



Near Nogagus in the joints of the cephalothorax and abdomen, and m 

 the feet and antennae. The cephalothorax having below, behind 

 the first antennae, a disk for attachment. 



The essential point of difference between this genus and Nogagus, 

 is the existence of two large transparent lenticular corneae (conspi- 

 cilla), exactly like those of the Sapphirinae. These conspicilla are 

 attached to the exterior shell, but with some difficulty may be sepa- 

 rated. On pressure they proved to be brittle, though rather hard. 

 The lenses of the eyes are situated below, near the conspicilla, though 



