ISOPODS OF NORTH AMERICA. 



683 



FIG. 726. LlGYDA PALLASII (AFTER STJMPSON). X ly. 



Body oblong-ovate, nearly twice as long MS broad, 11 nun.: 20 ram. 

 Length of uropoda from tip of terminal segment of body, 3 mm. 

 Length of body, including uropoda, 23 mm. Surface covered with 

 minute granules. 



Head more than twice as wide as long, 2 mm. : 5 mm. Anterior mar- 

 gin widely rounded. Eyes large and round, composite, and situated 

 close to the lateral margins. 

 First pair of antennae incon- 

 spicuous and rudimentary 

 and composed of two short, 

 subequal articles and a mi- 

 nute terminal article. The 

 first antennae extend only to 

 the end of the first article of 

 the peduncle of the second 

 an te n n 83 . Th e fi rst t wo arti- 

 cles of the second pair of an- 

 tennae are equal in length; 

 the third is nearly twice as 

 long as the second; the 

 fourth is one and a half times 

 longer than the third; the 

 fifth is one and a half times 

 longer than the fourth. The flagellum is composed of twelve articles. 

 The second pair of antennae extend to the middle of the fourth thoracic 

 segment when retracted. The maxilliped has a palp of five articles. 



The first four segments of the thorax are subequal; the last three 

 are somewhat shorter in the median dorsal line. The lateral portions 



of the last three segments extend 

 downward. The epirnera of all the 

 segments are broad plates, occupying 

 the whole of the lateral margins of 

 the segments and indicated by dis- 

 tinct lines. 



The abdomen is as wide as the tho- 

 rax, the lateral parts of the third seg- 

 ment extending as far as the lateral 

 parts of the seventh thoracic seg- 

 ment. The lateral parts of the first 

 two segments of the abdomen are not 

 developed; those of the last four segments are well developed and 

 have the posterior angles produced downward. The lateral parts are 

 not separated off from the dorsal portion of the segments. On the 

 lateral parts of the third, fourth, and fifth segments are distinct carinre 

 extending obliquely from the middle of the segment to the posterior 



FlG. 727. LlGYDA PALLASII. a, MAXILLIPED. 

 X 20^. b, FIRST LEG OF MALE. X 7J. 



