NO. 1507. FRESH- WA TER AMPHIPODA— W ECKEL. 3 3 



dactyl stout, slightl,y curved, extendino- to tlie posterior margin of 

 the palm. 



Carpus of tlie second gnathopods in the male like that of the tirst 

 pair; propodus more elongated than in the first pair, lu'oadened dis- 

 tally; palm oblique, somewhat arcuate, armed with fifteen or moi'e 

 spines similar to those of the first pair, but not crowded into a group 

 at the posterior angle; posterior margin of hand with five or six 

 groups of hairs; dact} I strongly curved, as long as the palm. In the 

 female the propodus of the second gnathopods is proportional!}^ more 

 elongated than in the male and does not increase in breadth distally. 



Third, fourth, and fifth perttopods with the coxal plates serrate, and 

 with small spines on both margins. 



Postero-lateral angles of the first three segments of the abdomen 

 produced, terminating in a small tooth. 



First pair of uropods projecting fiackward beyond the second and 

 third pairs, two rami equal and about two-thirds as long as the pedun- 

 cle; second pair with rami equal, and equal in length to the peduncle; 

 third pair short, reaching to the tip of the second pair, peduncle 

 short; outer ranuis about twice the length of the peduncle, inner 

 ramus ver}' small, slender, shorter than the peduncle, usuall}^ without 

 spines or hairs. Telson slightly shorter than the peduncle of the 

 third uropods; about as broad as long, cleft about one-third the dis- 

 tance to the base with two or three spines on the truncate extremities 

 of the lobes. 



The specimens of this species differ greatly in size, varjnng in ma- 

 ture specimens from T-IS mm., but the larger ones agree in all essen- 

 tial features with the smaller. 



Dhtrihution. — Providence, Rhode Island; Ann Ai-))or and Isle 

 Royal, Michigan; Lake Huron; Lake Superior; Portage, Wisconsin; 

 Champaign, Illinois; Irvington, Indiana; Delaware, Ohio; Nashville, 

 Tennessee. 



This species can not belong to the genus Crangoni/x to which it was 

 assigned b}^ Smith. That genus as generally defined has the third 

 uropods uniramous and the telson entire. The new genus Eucran- 

 gonyx^ in which this species has been placed bv Stebbing, is like Cran- 

 gonyx in general, but with a small inner ramus to the third uropods 

 and with the telson emarginate. 



EUCRANGONYX BIFURCUS (O. P. Hay). 



Crangonyx bifurcus O. P. Hay, Am. Nat., XVI, 1882, pp. 145-146. 



Eyes oval, large, about twice as large as those of Eucrangonyx 



gracilis which this species resembles. First antennae not quite half 



the length of the body; third segment of the peduncle two-thirds as 



long as the first or second segments, which are nearlj^ equal; fiagellum 



Proc. N. M. vol. xxxii— 07 3 



