SUBTERRANEAN AMPHIPOD STYGONECTES 31 



Type locality. — Witheros Cave, Bath Co., Va. The type series 

 was collected from a small, gravel-bottom stream in the lower level. 



Distribution and ecology. — This species is known only from 

 its type locality in eastern Bath Co. where it occm^s syn topically with, 

 and apparently in greater abundance than, S. mundus. One ovigerous 

 female (6.00 mm in length) was noted in the Mar. 23, 1941 collection. 



It is a pleasure to name this species after its collector, Dr. J. P. E, 

 Morrison of the Division of MoUusks, U.S. National Musemn, one 

 of the early explorers and sm-veyors of Witheros Cave. 



Stygonectes cooperi, new species 



Figure 5 



Material examined 



WEST VIRGINIA.- — Berkeley Co.: Silers Cave, male holotype (USNM) and male 

 paratype, J. R. Holsinger and J. E. Cooper, Feb. 16, 1963. (Holotype, partially 

 on a slide mount; paratype temporarily retained in JRH.) 



Diagnosis. — Easily distinguished from other species in the emar- 

 ginatus group by the distinctly convex posterior margins of bases of 

 pereopods 5-7 and by the presence of simple, lateral sternal gills on 

 pereonites 6 and 7. Largest male, 6.00 mm; female unknown. 



Male (holotype). — Antenna 1 about 50 percent as long as body, 

 about 1/2 times longer than antenna 2; primary flagellum of 20 

 segments. Antenna 2 with 7 flagellar segments. Mandible: palpal 

 segment 3 with 6 or 7 long setae; segment 2 with 7 to 9 setae. MaxUla 

 1, inner plate with 7 plumose setae apically. Maxilla 2, inner plate 

 with 7 long, obliquely placed, plumose setae. Maxilliped, outer 

 plate reaching nearly to apex of 1st palpal segment. Lower lip with 

 small inner lobes. 



Gnathopod 1 : propod palmar margin nearly straight to slightly 

 concave, armed with a double row of about 8 spme teeth; posterior 

 margin with 3 large, unequal spines on outside, about 5 smaller spines 

 on inside; lateral setae few in number, singly inserted; claw of dactyl 

 long. Gnathopod 2: propod palmar margin slightly concave, armed 

 with a double row of 11 or 12 spine teeth; posterior margin with 1 large 

 spine on outside, about 4 small spines on inside; lateral setae few in 

 number, mostly doubly inserted; dactyl claw long. Coxal plates 

 of pereopods 2 and 3 with 5 or 6 marginal setae and spinides each; 

 that of pereopod 4 with about 7 marginal setae. Bases of pereopods 

 5-7: posterior margins somewhat produced posteriorly, convex; dis- 

 toposterior lobes small, poorly defined. Dactyls of pereopods 5-7 

 between 35 and 40 percent as long as corresponding propods. Seventh 

 pereopod coxal gUls and pleonite sternal gdls absent; paused lateral 

 sternal gills on pereonites 6 and 7 simple, not bifurcate. 



