434 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxv. 



abundant near the palmar .surface and the distal end of the superior 

 margin. The dactjd is about one-half as long as the hand, strongly 

 curved and very acute. 



The second pair of legs differs from the first not only in size l)ut in 

 the shape of all the segments and their armature of hairs and bristles. 

 The carpus is more perfecth^ triangular in profile, but has an almost 

 exactl}^ similar arrangement of ])ristles. The hand is somewhat <]uad- 

 rangular; its superior and inferior margins are subparallcl and the 

 palmar surface is onl}^ slightly oblique; there are a few teeth and hairs 

 at the sides of the palmar surface, another small bunch of slender 

 hairs near the articulation of the dactyl, and a rather extensive patch 

 of stiff hairs on the inferior margin. The dactyl is straighter than in 

 the preceding appendage and more blunt. 



The other pereiopods are similar to those of the Ga/)iniarld(G except 

 that the third and fourth are very hairy and the fifth, sixth, and sev- 

 enth have the basal segments much narrower, broadest at the proximal 

 end and gradually narrowing distally. 



Segments of the abdomen rounded al)ovc, the fourth, fifth, and 

 sixth with the posterior margin slightly produced in three places — one 

 in the middle and one very near the middle line on each side — and 

 armed with three small clusters of spines. The spines of the middle 

 clusters are rather smaller than those of the side clusters. 



Both rami of the posterior caudal stylets with many slender hairs 

 but no teeth. 



Telson divided almost to the base; each division with a spine near 

 the middle of the outer margin and a series of about ffve at the distal 

 extremity. 



This species resembles Gammani^; luunxus Smith, but has much 

 longer antenna^, larger eyes, differently arranged spines, and a differ- 

 ent telson. Judging from Smith's ffgure ^ the posterior caudal stjdets 

 are much longer in G. Uiimse.us. The second antenna^ of G. i^urpur- 

 asceu.H have fewer segments than G. llmncnus, but the difference is 

 more than made up by the very numerous segments of the tirst 

 antenna\ 



The variation in the number of segments in the ffrst antenna3 is 

 apparently dependent upon sex and age; the}" are longest in fully 

 adult males, slightly shorter in adult females, and shortest in the 

 young, without distinction as to sex. 



I found this species quite common among the growing vegetation 

 and decaying wood in a pool at the mouth of the cave. In color they 

 were a dark purplish gray and their movements in the watei- were very 

 quick, so that their capture was quite difficult. I also found them in 

 the spring at Rossville, Georgia, but of smaller size and in fewer 

 numbers. 



Kept. U. y. Comm. Fish and Fisheries, 1872-73, p. 651, pi. ii, %. G. 



