CRUSTACEANS OF NICKAJACK CAVE— HAY. 



433 



GAMMARUS PURPURASCENS, new species. 



Type.—^o. 25544, U.S.N.M. Collected September 6, i!M)l, hj 

 W. P. Hay, at the mouth of Nickajack Cave, Shellmound, Tennessee. 



E^'es large, reniform, with the concavity anterior. Head large, 

 deep, notched in front for both antenna, and with a very short ros- 

 trum. First antennfB about half as long- as the body, with a small sec- 

 ondary flagellum of three articles; flagellum with from twenty to 

 thirty articles; all the basal segments and those of the flagellum plen- 

 tifully provided with hairs. Second antennae a little over half as long- 

 as the first pair; first basal segment short and broad, second and third 

 short, the second with a spine on the inferior margin; fourth and fifth 

 segments of nearly equal length, each longer than the first three seg- 



FlG. 7.— GAMMARUS PURPURASC 



a, Left lateral view of adult male, (j, Legs of first pair. 



6, First antenna. h, Legs of third pair. 



c, Second antenna. /, Legs of seventh pair. 



d, Mandible. j, appendage of eleventh seg 



e, Third maxillipeds. ment. 



, NEW SPECIES. 



I, Appendage of thirteenth seg- 

 ment. 



Ill, Dorsal view of abdomen and 

 appendages. 



n, Telson. 



/, Legs of second pair. 



A-, Appendage of twelfth segment. 



ments together; flagellum, composing about one-third of the append- 

 age, of nine articles. All these segments, like those of the first antennae, 

 are plentifully provided with stifi' hairs, and the segments of the fla- 

 gellum bear, in addition, each a particular mushroom-shaped sense 

 organ. 



First pair of legs of the male strong, but of slightl}" smaller size 

 than those of the second pair. The carpus is short and broadly trian- 

 gular; its distal margin, especially near the inferior angle, is abun- 

 dantly supplied with long bristles. The hand slightly broader than the 

 carpus, its superior and inferior margins convex, the palmar surface 

 very oblique and armed on each side with scattered spines and teeth 

 between which the dact}^ closes; the bristles on the hand are most 

 Proc. N. M. vol. XXV— 02 -1^ 



