ISOPODS OF NORTH AMERICA. 



225 



Bod}' oblong-ovate, nearly twice as long as wide, 10 mm. : 19 mm. 



Head a little wider than long, 3 mm. :4 mm., with the anterior mar- 

 gin rounded truncate and the posterior margin produced in three lobes, 

 the middle lobe being deeper than and about twice as wide as the lateral 

 lobes. The eyes are entirely absent; no traces of them are to be seen. 

 The first pair of antennae are composed of eight articles and extend 

 to the middle of the first thoracic segment; they are separated at the 

 base by a distance of 1 mm. The second pair of antennae are composed 

 of nine articles and extend only a little beyond the end of the first pair 

 of antennae. 



The first thoracic segment is 2 mm. long, about twice as long as any 

 of the three following segments, which are each 1 mm. long in the 

 middle of the dorsal surface. The fifth segment is 1 mm. in length. 

 The sixth segment is as long as the first about 2 

 mm. in length. The seventh segment is 1 mm. 

 long only half as long as the preceding segment. 

 The post-lateral angles of the first four segments 

 are but little produced. The post-lateral angles of 

 the last two segments are very much produced, 

 those of the seventh segment being more produced 

 than those of the preceding segment. The epimera 

 of the second, third, fourth, and fifth segments 

 extend to the post-lateral angles of their respective 

 segments. Those of the second and third segments 

 are rounded posteriorly. Those of the fourth and 

 fifth segments are obtusely pointed. The epimera 

 of the sixth and seventh segments are very acutely 

 produced and extend to the posterior margins of 

 their respective segments, but not to the post- 

 lateral angles. The first five segments of the abdomen are subequal 

 and all visible in a dorsal view, the first segment not being covered by 

 the last thoracic segment. The first two have the lateral parts pro- 

 duced in long acute processes on the underside, these processes not 

 being visible from a dorsal yiew. The lateral parts of the other seg- 

 ments are not produced. The sixth or terminal segment is as wide as 

 long 5 mm. :5 mm. and is longer than all the five anterior segments 

 taken together 5 mm. : 4 mm. It is triangular in shape, with apex 

 produced and rounded. The uropoda are shorter than the last abdom- 

 inal segment, the inner branch being the shorter. a 



The inner branch is probably broken in the specimen, for this branch is described 

 by Say as triangular, whereas it appears truncate in the specimen. 

 2858905 15 



FiG.229. NEROCILA LAN- 

 CEOLATA. x 3. 



