V °l889. n J PROCEEDINGS OF THE NATIONAL MUSEUM. 633 



Anterior process of the epistoma triangular, the apex truncated or even 

 notched. Anteunte shorter than the body; scale broad, broadest 

 near the tip. Chelipeds stout, chela broad, punctate, external margin 

 convex, internal margin furnished with a double row of tubercles ; 

 fingers slightly gaping, costate, vith longitudinal rows of ciliated 

 dots; external margin of movable finger with a line of ciliated tuber- 

 cles; tips of fingers incurved, corneous. Carpus smooth, furnished 

 with a well developed internal median and small proximal and distal 

 internal spines; beneath, the carpus has a well developed median 

 anterior spine, and a very minute external spine at the point of articu- 

 lation with the chela. Meros furnished with two obliquely placed 

 ante-apical spines ; of the biserial inferior spines the outer row is rep- 

 resented by the two distal ones only. Third pair of legs hooked. First 

 pair of abdominal appendages very long, reaching the base of the 

 chelipeds, tuberculare on inner border near the base, bifid, anterior bor- 

 der carinate, rami straight, thick ; the outer branch much longer than 

 the inner, the tip slightly recurved, the inner branch blunt at the tip, 

 and bent a little outward and backward. Dimensions: length C0 mm ; cara- 

 pace, 29 ,1Hn ; from end of rostrum to cervical groove, 18.5 mm ; from 

 cervical groove to posterior margin of carapace, 9.5 IUIU ; breadth of ros- 

 trum at base, 3.5 mm ; between lateral spines, 2.5 nnu ; breadth of areola, 

 2 mm ; abdomen, 31 mm ; chela, 23 mm ; breadth of chela, 10 mm ; movable 

 finger, 13.5 nuu . 



Female: Chela smaller, fingers not gaping, external finger slightly 

 bearded at the base within. Sternum between the fourth pair of legs 

 not tuberculate. Anuulus ventralis large, triangular, the anterior mar- 

 gin obsolescent, posterior margin very prominent, projecting backward ; 

 fossa transverse, deep, with a sigmoid sulcus. 



West Fork of Black River, Reynolds County, Missouri, R. E. Call 

 (M. C. Z.). Four males, form II; two females. 



This species is closely related to G. putnami Fax., but the sides of 

 the rostrum are more thickened and more convergent from the base to 

 the lateral spines ; the antennal scale is widest near the tip (in C. 

 putnami it is widest in the middle) ; the carpus has a well developed 

 anterior spine, and the aunulus ventralis is very different. From 

 C. spinosus Bundy, it differs in its longer metacarapace, shape of the 

 rostrum, aunulus ventralis, etc. 



Cambarus forceps Fax. 



Additional locality: Middle Fork of Holston River, Glade Spring, 

 Virginia. D. S. Jordan (U. S. F. C). Four males, form I ; four females* 

 The specimen from Knoxville, Tennessee, mentioned on page 121 of 

 the Revision, surely belongs to this species. 



Cambarus montezumae Saus. 



Additional locality: Guanajuato, Mexico. A. Duges (IT. S. N. M.). 

 C, montezumcv is a variable species. In the specimens from Guauajuato 



