46 PROCEEDINGS OF THE NA TIONAL MUSEUM. vol. xxxii. 



pahn very oblique, continuous with the posterior margin and furnished 

 with a few short hairs on each side, a fascicle of long ones at the cen- 

 ter, and a few spines at the tip of the closed dact}^; the posterior and 

 anterior margins of the propodus convex, the posterior one provided 

 with a few fascicles of long hairs and one or .two small spines near 

 the palm; dactjd strongl}^ curved, half as long as the propodus. 



Second gnathopods with the propodus rectangular, more than half as 

 broad as long; lateral margins only slightly convex, the posterior with 

 about eight fascicles of long hairs; palm oblique, furnished as in the 

 first pair except that no spines extend upon the posterior margin; dac- 

 t}^ not so strongly curved as in the first pair, extending slightly beyond 

 the palm. 



Basal plates of the third, fourth, and fifth perj\?opods narrow, broad- 

 est proximally, with margins^'serrate and furnished with a few spines. 



Three posterior segments of the abdomen rounded dorsally, each 

 furnished with three small fascicles of spines; the spines of the median 

 fascicles smaller than those of the lateral ones. 



First pair of ul-opods slightly exceeding the second pair in length, 

 projecting somewhat beyond the peduncle of the third; third pair with 

 a short peduncle onl}' slightly longer than broad; the outer ramus con- 

 sisting of two segments, the basal one long and narrow with four or 

 five spines on the outer mai'gin and many long plumose hairs; termi- 

 nal segment very short, styliform, and furnished distally with a few. 

 long hairs; inner ramus about three-fourths as long as the basal por- 

 tion of the outer, with many long plumose hairs and usually a few 

 spines on the inner margin. Telson divided almost to the base, with 

 a spine and a few hairs on the outer margin, and three or four spines 

 and a few short hairs distally. 



Length, 10 mm. 



The t3^pe specimens of this species w^ere collected at the mouth of 

 Nickajack Cave, Shellmound, Tennessee. Specimens of a smaller size 

 have also been found in a spring at Rossville, Georgia. 



GAMMARUS PROPINQUUS W. P. Hay. 



Gainmarus prophujaus W. P. Hay, Proc. U. S. Nat. INIus., XXV, 1902, p. 224. 



This species is ver}^ similar to Ganvmarus fasciattis Say, but difl'ers 

 from it in the following characters: The secondary flagellum consists 

 of from two to five segments; in Gaviinm'nsfasciatusiYom. five to six. 

 The palm of the first gnathopods of the male in G. fasdatus is more 

 irregular and more concave. In the second gnathopods it is more 

 concave and slightly more oblique than in Gaminarus j^i'opmquus. 

 The best distinguishing characteristic, however, is in the third uropods, 

 the inner ramus. of which in Gammarus propinquus is much more 

 slender than the outer and half or onlv slightly more than half as long. 



