Proceedings of 

 the United States 

 National Museum 



SMITHSONIAN INSTITUTION • WASHINGTON, D.C. 



Volume 123 1967 Number 3602 



The Crayfishes and Their Epizootic 



Ostracod and Branchiobdellid Associates 



Of the Mountain Lake, Virginia, Region l 



By Horton H. Hobbs, Jr., Perry C. Holt, 

 and Margaret Walton 2 



The Mountain Lake Region, as here considered, comprises approx- 

 imately 500 square miles (1290 square km) in Craig, Giles, and 

 Montgomery Counties, Va., and Monroe County, W. Va. Here 

 the altitude varies from 396 m (1300 ft) at New Castle, Craig County, 

 to 1329 m (4363 ft) at Bald Knob on Salt Pond Mountain in Giles 

 County. Waters draining from the area contribute to three major 

 river systems — the New River flowing to the Ohio and Mississippi 

 Rivers, the James River to Chesapeake Bay, and the Roanoke 

 River to Albemarle Sound, N.C. 



Except for a few sphagnum bogs, sinkhole ponds, and impounded 

 streams, the only lentic habitat larger than a few feet in diameter 

 is the oligotrophic Mountain Lake situated at an elevation of 1180 m, 



1 A contribution from the Mountain Lake Biological Station of the University 

 of Virginia and the Department of Biology of the Virginia Polytechnic Institute. 

 The branchiobdellid studies were supported by grants (NSF G-4439, G-9828, 

 GB-372) from the National Science Foundation. 



2 Hobbs: Smithsonian Institution; Holt: Virginia Polytechnic Institute; 

 Walton: Mountain Lake Biological Station. 



1 



