70 A REVISION OF THE ASTACID.E. 



the post-orbital ridges. In the form from Bridgeport and Ashhuid City it is 

 equal to the distance from the cervical groove forward to the anterior sjnnes 

 of the post-orbital ridge. 



25. Cambarus dubius. 



Plato IV. tig. 3, Plate VIII. Hgs. 7, 7. 

 Cambarus dubius, Faxon, Pioc. Anici-. Acad. Arts and Sci., XX. 114, 1884. 



Rostrum short, broad, sides subparallel from the base to near the tip, 

 when they suddenly converge to form the short, broadly triangular acu- 

 men ; the rostrum is angulated, but not toothed, at the base of the acumen ; 

 upper surface of rostrum concave, sides thickened, punctate-lined. Post- 

 orbital ridges without spines, slightly swollen at the posterior end. Cara- 

 pace longer than the abdomen, oval, punctate, granulated on sides, posterior 

 dorsal margin depressed, cervical groove hardly sinuate, crossing the median 

 line of the back half-way between the base of the rostrum and the poste- 

 rior margin of the carapace ; lateral and branchiostegian spines obsolete ; 

 sub-orbital angle little developed, obtuse ; areola narrow, with two irregu- 

 lar longitudinal rows of dots. Epistoma subquadrangular. Abdomen small, 

 short ; anterior segment of telson bispinose on each side, posterior segment 

 rounded behind. Antennge shorter than the body, second and third segments 

 without spines, scale small. External maxillipeds hairy within. Chela punc- 

 tate, inner margin of hand serrato-tuberculate, outer margin thickened, 

 serrate ; fingers somewhat down-curved, slightly gaping, toothed on their 

 opposed margins. Carpus with a strong tooth on the inner side, teeth of 

 the lower side obsolescent. Superior border of meros serrate, lower side 

 armed with two rows of spines. Third pair of legs hooked. First pair of 

 abdominal legs of the first form of the male short, thick, twisted ; internal 

 part cylindrical, recurved, with pointed apex ; external part broader, plane 

 within, apex recurved, compressed, external margin corneous, sti'iated. 



Length, 62 mm. Carapace, 33.5 mm. Abdomen, 28.5 nun. Rostrum, 

 5 mm. Metacarapace, 15 mm. Width of areola, 1.5 mm. 



Known Localiiics. — West Virginia: Cranberry Summit, Preston Co. Vir- 

 ginia : Pennington's Gap, Lee Co. Tennessee : Cumberland Gap. 



This species has the general appearance of C. Diogenes, but the rostrum 

 is short, as in C. Bartonii, and the areola is not obliterated in the middle 



