146 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 91 



Subgenus Cambarus Erichson (1846) 



CAMBARUS (CAMBARUS) CAHNI, new species 



Male I. — Unknown. 



Male II. — Body white, digestive tract dark. Rostrum of mod- 

 erate length, sides converging and sharply elevated. Marginal spines 

 small and often reduced to angles. Acumen rather short and broad. 

 Broad median carina reaching to a line drawn between the post- 

 orbital spines. Carapace slender, rounded, and minutely granular 

 on the sides. Cervical groove sinuate but unbroken, on the sides 

 above small rounded tubercles. Lines of the areola not clearly de- 

 fined. Length of areola varying from 36.7 to 40.5 percent of the 

 length of the carapace. Width accommodating three rows of widely 

 spaced dots. Epistoma oval, with small acute terminal spine. 

 Lateral margins sharply elevated. Antennae reaching to the telson 

 or beyond. Antennal scale triangular, broadest anterior to the 

 middle. Apical spine short. Chelae rather smooth, two or three 

 rows of low tubercles on the inner margin of the palm. Dots dis- 

 tributed evenly over the hand but tending to form furrows on the 

 dorsal surface of the fingers, two on the immovable finger and three 

 on the movable finger. Fingers two to three times the length of the 

 inner margin of the palm and twice as long as the width of the 

 palm. Merus with prominent furrow in the dorsal surface. Sharp 

 spine on inner surface with to 3 small accessory spines. Carpus 

 with usual biserial row of spines down the ventral. Outer series 

 much exceeded by the inner. Hooks on the third walking legs rather 

 sharp and recurved. Gonopods thick, with fleshy tips recurved at 

 right angles with the shank. Inner ramus with tips slightly out- 

 curved as well as recurved. Setae on the ventral line. 



Female. — Chelae slightly shorter. Annulus broadly ovate. Cen- 

 tral and posterior regions elevated. Anterior wall somewhat de- 

 pressed. Fossa anterior and shallow. Median furrow curved to 

 form a small blunt hook to the observer's left in a central position. 



Affinities. — G. cahni is intermediate between the "Section of G. 

 hamulatus^'' and the "Section of G. extraneus'^ (Ortmann, 1931, pp. 

 95-96). However, the cave modifications place it in the former 

 section. The carapace is subcylindrical, the chelae are long and 

 subcylindrical, and the eyes are greatly reduced, though not to the 

 extent found in G. hanmlatus. The gonopods are recurved and the 

 lateral spines are present on the rostrum. I believe this crayfish has 

 sufficient constant and peculiar characteristics to give it the status 

 of a distinct species. 



I possess a female crayfish from Saddler Springs Cave that is 

 lightly pigmented on the carapace and the dorsum of the abdomen. 

 It bears close resemblance to G. cahni in the subcylindrical carapace 



