ISOPODS OF NORTH AMERICA. 



445 



FIG. 500. STENETRIUM STEBBINOI. a, THIRD PLEOPOD OF MALE, x 

 41. b, FIRST PLEOPOD OF MALE, x 77. c, SECOND PLEOPOD OF 

 MALE, x 77i. 



two following joints narrow; the flagellum is composed of nine joints 

 and reaches a little beyond the middle of the fourth peduncular joint 

 of the second pair of antenna 1 . 



The second pair of antenna? have the first four joints short, the 

 third joint being provided with an exopod, the fifth and sixth joints 

 long and of equal length; the flagellum is multi-articulate. 



The first thoracic segment has the lateral margins straight, the ante- 

 rior angles acutely 

 produced forward. 

 The lateral margins 

 of the second, third, 

 and fourth segment 

 are also straight, w ith 

 the epimera evident 

 about the middle. 



The fifth and sixth 

 segments have the 

 posterior half of 

 the lateral margin 

 rounded, the epimera 

 evident below. The 

 seventh segment has the lateral margin acutely produced posteriorly, 

 the epimera evident on the posterior margin of the segment within 

 the processes. The thoracic segments are all widel\ T separated from 

 each other by deep lateral incisions. 



The terminal segment of the body has the lateral margin produced 

 backward in two small spines, between which the posterior margin 



is widely rounded. The 

 uropoda are double 

 branched, the branches 

 being nearly equal in 

 length and about as long 

 as the basal joint. 



The first pair of legs 

 are subchelate. In the 

 male the carpus is pos- 

 tero - distally produced 

 in a markedly long pro- 

 cess, which extends half 

 the length of the propodus, its entire margin being fringed with 

 long hairs. The propodus is elongate, its lower two-thirds being 

 fringed with long hairs on the posterior margin, the upper third or 

 distal margin being provided with three large spines, the inner one 

 being bifurcate; the dactylus is long and also fringed with hairs upon 

 its inner margin, and extends half its length beyond the last digital 



FIG. 501. STEXETRIVM STEBBIXGI. u, FOURTH PLEOPOD OF 

 MALE, x 41. 6, FIFTH PLEOPOD OF MALE, x 41. c. FIRST 



PLEOPOD OF FEMALE. X 77. 



