22 U.S. NATIONAL MUSEUM BULLETIN 259 



land and then southwest through the Appalachians to Alleghany Co., 

 Va., and Greenbrier Co., W. Va. To date all collections, with one 

 exception, have been made from cave water, i.e., pools and small 

 streams. Seven distinct species, all but one of which have narrowly- 

 defined ranges, are presently recognized. 



Key to Species of the emarginatus Group 



1. Telson gently tapering distally, armed both laterally and apically with spines, 



apical margin entire {gracilipes subgroup) 2 



Telson not much tapered distally, without lateral spines, apical margin usually 

 with a shallow excavation {emarginatus subgroup) 3 



2. Ramus of uropod 3 reduced, armed apically with a single spine; large species, 



females up to 18.00 mm; known from 4 caves in the Appalachian Valley 

 from FrankUn Co., Pa., south to Warren Co., Va. 



S. gracilipes, new species 



Ramus of uropod 3 not reduced, armed apically with 3 or 4 spines; smaller 



species, largest known female 8.25 mm; known only from Breathing Cave, 



Bath Co., Va S. conradi, new species 



3. Apical margin of telson entire, without shallow excavation; subterranean 



waters of eastern Alleghany and Bath Co., Va . . . S. mundus, new species 

 Apical margin of telson with a shallow excavation 4 



4. Adults relatively large, 9.50 to 14.25 mm; 4th and 5th peduncular segments 



of antenna 2 with several sets of rather long, stiff setae; posterior corners 



of abdominal side plates well developed, subacute to acute 5 



Adults relatively small, 6.00 to 7.00 mm; 4th and 5th peduncular segments of 

 antenna 2 less setose; posterior corners of abdominal side plates usually 

 less acute, sometimes poorly developed 6 



5. Posterior margin of 1st gnathopodal propod with 2 or 3 sets of setae; telson 



with 18 to 20 apical spines; known only from Millers Cave, Centre Co., Pa. 



S. stellmacki, new species 



Posterior margin of 1st gnathopodal propod without setae; telson with up 



to 14 apical spines; 3 caves in Greenbrier Co., W. Va., and 1 cave in Garrett 



Co., Md S. emarginatus (Hubricht) 



6. Bases of pereopods 5-7 with distinctly convex posterior margins; lateral 



sternal gills simple, not bifurcate; known only from Silers Cave, Berkeley 



Co., W. Va S. cooperi, new species 



Bases of pereopods 5-7 with nearly straight or only slightly convex posterior 

 margins; lateral sternal gills bifurcate; known only from Witheros Cave, 

 Bath Co., Va S. morrisoni, new species 



EMARGINATUS Subgroup 



Diagnosis. — Posterior angle of 1st gnathopodal propod with up 

 to 3 large, unequal spines on outside. Distoposterior lobes of bases 

 of pereopods 5-7 distinct but not broad or much produced ventrally. 

 Telson without lateral spines, longer than broad, nearly as broad 

 distally as proximally; apical margin armed with up to 18 spines and 

 usually with a shallow excavation (except for one species in which the 

 telson is not emarginate). 



