no. 3602 CRAYFISHES — HOBBS, HOLT, AND WALTON 27 



Remarks. — This crayfish is the dominant decapod inhabitant of 

 the riffle areas in the James and Roanoke river systems. Except 

 from November to April, this small crayfish can be found in almost 

 every riffle in the lower mountains and piedmont. During the colder 

 months, individuals retreat to their burrows beneath stones in the 

 riffles. At least some of the tunnels descend to depths greater than 

 30 cm. Because of the sand, gravel, and interlocking stones sub- 

 merged in the current, it is exceedingly difficult to dissect a burrow. 

 Even though we have removed specimens from such burrows, we are 

 not at all certain that we determined the full extent of the excavations. 

 In the spring, the adult males and juveniles leave the burrows first; 

 the females remain in their tunnels, where presumably they lay and 

 hatch their eggs before venturing into open water. Not until mid- 

 May can one sample the riffle and expect to obtain a knowledge of 

 all the components of the C. I. longulus population. 



The life history of this crayfish has been briefly outlined above; 

 for details, see Smart (1962). 



Cambarus sciotensis Rhoades 



Figure 5 

 Cambarus bartoni sciotensis Rhoades, 1944, p. 96. 

 Cambarus sciotensis Hobbs, 1964, p. 189. 



Diagnosis. — Margins of rostrum subparallel or slightly convergent 

 to base of acumen where suddenly contracted to form angles of 

 approximately 90° (or with slightly protruding knobs), thickened but 

 without marginal spines; areola never more than six, usually about 

 four and a half times longer than broad with deep, but not crowded, 

 punctations; suborbital angle obtuse. Chela with subovate fingers 

 bearing distinct median longitudinal ridges on upper surfaces; fingers 

 may or may not be gaping but never provided basally with conspicuous 

 tuft of setae; inner margin of palm with two rows of tubercles. 



Range. — Apparently discontinuous; in the Scioto River in Ohio 

 and in the New River system in Virginia and southeastern West 

 Virginia (both areas in the Ohio drainage system). 



Specimens examined. — Approximately 450 specimens in 43 

 collections from the following stations: 3, 5, 15, 18, 19, 43, 44, 50, 

 54-59, 61-67, 70, 72, 73, 75, 78-81, 84, 86, 95-97, 102, 104-109, 116, 

 and 126. All of them are in the New River drainage system at 

 elevations of 427 to 899 m. 



Associates. — The only crayfish associate was C. b. bartonii, which 

 was found at the following stations: 3, 5, 19, 44, 50, 54, 57, 59, 63, 

 64, 66, 95-97, 107, and 108. 



Ostracod associates include Dn. ileata at all stations except 70 and 

 78; Dn. scalis at 44; Dn. truncata at 54-57; Dt. daphnioides at 70, 72, 



