272 BULLETIN 54, UNITED STATES NATIONAL MUSEUM. 



A single dried specimen of this species, the type, is in the Philadel- 

 phia Academy of Natural Sciences. 



The body is ovate, about twice as wide as long, 6 mm. : 12 mm. 

 The head is short and wide, being 1 mm.: 4 mm., with lateral mar- 

 gins and lateral angles rounded. The anterier margin is produced in 

 a linguiform median process extending forward over the basal articles 

 of the first antennae. 



The segments of the thorax are subequal. 



The first segment of the abdomen is almost entirely concealed. The 

 second or terminal segment is 4 mm. long and 5 mm. wide at the base. 

 It is triangular in shape, with apex funnel-shaped, the sides being 

 turned downward and inward. The uropoda are single-branched, and 

 are in the form of a long, narrow, tapering branch, posteriorly acute, 

 and extending to the tip of the terminal abdominal segment. This 

 branch seems fixed to the sides of the abdomen, 

 and immovable. There is no trace or indication 

 of an outer branch. 



The first pair of antenna? have the first three 

 peduncular articles dilated, and of nearly equal 

 length. 



As the dried specimen is glued to a piece of 

 paper, nothing can be ascertained of the structure 

 FIG. 282.-ANCINUS DE- of the legs. a 

 PRESSUS. ABDOMEN WITH The specimen was evidently formerly mounted 



UROPODA. X 6. . . , , ,' . . . 



on a pin, as there is a hole in the paper and 

 through the body of the specimen, breaking it at about the middle. 



46. Genus CASSIDISCA, new genus. 



Body oval, depressed. 



Maxillipeds with second, third, and fourth articles of palp not pro- 

 duced into lobes. 



Abdomen composed of two segments, the first segment formed by 

 the fusion of several segments. 



The inner branch of the uropoda is large and well-developed, and is 

 immovable and firmly fixed to the side of the abdomen. The outer 

 branch is rudimentary and very short, and not entirely separated from 

 the inner branch, sometimes being represented by a small incision in 

 the exterior margin of the inner branch. 



Legs all ambulatory. 



This genus is quite similar to Scuteloidea Chilton, but differs, according to Say, 

 in having the first two pairs of legs subchelate, while in Scuteloidea the legs are all 

 ambulatory. 



