394 CRAYFISHES. 



are rather short, strongly curved downward or inward, not conspicuously ribbed, 

 their prehensile margins armed with rounded teeth, the free edge of the dactylus 

 furnished with low, ciliated, squamous tubercles. 



Antennal scale small, narrow. Anterior process of the epistome broad, 

 truncate, anterior border concave, with a median tooth. Sexual organs of male 

 and female similar to those of C. hartonii. 



Dimensions of a female specimen: — length, 113 mm. length of cephalotho- 

 rax, 54 mm., breadth, 29 mm., height of do., 21 nmi.; length of areola, 21 mm., 

 breadth of areola, 1.5 mm.; length of cheUped, 75 mm.; merus, 21 mm.; length 

 of chela, 39 mm. ; breadth of chela, 19 mm. ; length of dactylus, 24 mm. 



Bear Creek, a tributary of Green River, Grayson Springs, Grayson Co., 

 Ky., Oct. 24, 1874, F. W. Putnam coU. 1 male of the second form, 3 females. 

 M. C. Z., No. 3,593. 



This species is nearly related to C. ortmanni. Its form, like that of C. ort- 

 manni, denotes a species of fossorial habits, but not so preeininently addicted to 

 subterranean life as the species of the C. diogenes group, in which the cephalo- 

 thorax suffers a greater lateral compression. Compared with C ortmanni, 

 C. graysoni is more depressed dorsally, more heavily punctated, the areola is 

 broader (as broad as in the typical form of C. latimanus) the metathorax some- 

 what shorter in proportion to the prothorax, the suborbital angle is much more 

 salient, the anterior process of the epistoma is deeply emarginate in front, with a 

 prominent spine at the bottom of the emargination, the internal carpal spine is 

 acute even in old and large examples, and the tubercles of the inner (superior) 

 margin of the hand are stronger and biserially disposed. 



The specimens which form the types of C. graysoni were referred to C. har- 

 tonii in my Revision of the Astacidae, p. 61, 159, 169. The peculiarities of the 

 chelipeds, however, show that they belong to a distinct species, allied to C. 

 ortmanni and C. latimanus and forming together with these species a group con- 

 necting C. hartonii and its near allies with C. diogenes and the nearly related pre- 

 eminently burrowing forms. 



Cambarus ortmanni Williamson. 



Cambarus ortmanni Williamson, 31st Ann. Rept. Department Geol. Indiana, 1906, 1907, p. 754-760, 

 pi. 35. 



Camharus ortmanni, a burrowing species, was described by Mr. E. B. Wil- 

 liamson from specimens captured in Wells Co., Ind., in the Wabash River drain- 

 age near Bluffton. There has been a single female specimen from Cincinnati, O., 



