Dec, 1905.] A New Species of Cambarus. 403 



indicate the group of C. alleni. Within the latter group it 

 stands rather isolated with regard to the male organs, which 

 show a rather primitive conformation, within exception of the 

 distinct backward curve of the distal part. The shape of the 

 rostrum is peculiar on account of the almost triangular outline 

 (similar to C. advena), with hardly any traces of lateral angles 

 in the place of marginal spines. The areola is exceptionally 

 broad, broader than in any of the known species of this group. 

 The most striking character (disregarding the male organs) is 

 furnished by the chelae of the male, since the fingers are unusu- 

 ally short, shorter than in any other species of the genus. Thus 

 the new species is well characterized by the shape of the rostrum, 

 of the areola, chelipeds, and the male sexual organs. 



Its distribution agrees with that of the alleni-group, in so far 

 as it belongs of the lowlands of the coastal plain of the southern 

 United States. It is the most western locality known for this 

 group, being close to the Texas state-line (disregarding the 

 Mexican C. iviegmanni) . « 



