NO. 1507. FRESH- WA TEE A MPHIPODA— WECKEL. 3 1 



spines, with usually two large spines near the center and three at the 

 tip of the closed dactyl; dact}^ strongly curved, slightly longer than 

 the palm. First gnathopods of the female with the propodus smaller, 

 shorter, and broader distally than in the male. 



In the second gnathopods the carpus is slightl}' longer than l)road; 

 much larger than in the tirst pair; propodus not much larger than in 

 the tirst pair and not so broad; the posterior and anterior margins 

 only very slightly convex, the posterior furnished with more hairs 

 than in the tirst pair; palm longer than in the tirst pair, similarly 

 armed, but having a few more spines; dactyl strongly curved, as long- 

 as the palm. Propodus of the second gnathopods in the female not so 

 much elongated as in the male, but similarly armed. 



Coxal i)lates of the three posterior pera^opods oval, not large, with 

 both margins serrated. 



Abdominal segments rounded dorsally; the lateral margins and all 

 the angles broadly rounded. 



The tirst pair of uropods extend l)eyond the second pair, which 

 extend beyond the third; second pair not longer than the peduncle of 

 the first; tliird pair short, not quite so long as the peduncle of the 

 second pair; outer ramus ovate, truncate, about half the length of the 

 peduncle, provided distally and laterally with a few hairs; inner 

 ramus rudimentary, unarmed, a])Out one-third or one-fourth as long 

 as the outer ramus. 



Telson in the male c} lindrical, very nuich elongated, equaling from 

 one-fourth to one-third the length of the l)ody, rounded distally, and 

 furnished with two clusters of long hairs. In the female the telson is 

 short, projecting beyond the tips of the third uropods, having a very 

 slight emargination, on either side of which there is a cluster of long, 

 stout hairs. 

 _Length, 10-15 nuu. 



Collected in old wells at Irvington, Indiana; Champaign and 

 Normal, Illinois. 



The telson in the female of this species is somewhat incised posteri- 

 orly, l)ut less than is usual in this genus; in the male the telson is 

 entire and greatly elongated, a feature which does not accord with 

 the definition of the genus as originally given by Stebbing. The 

 other characters of this species, however, are so much like those of 

 the other members of this genus that it seems best to retain it in the 

 genus Eiicrangonyx^ to which it was assigned by Stebbing, rather 

 than to place it in a new genus, Bactrurus^ as proposed by Hay. 



