442 Annals of the Carnk(;ie Museum. 



genus, chiefly from the typical subgenus Cambarus, renders the Mexi- 

 can crayfish-fauna 'rather peculiar. In Mexico, two well known sub- 

 genera are represented : Procambanis and Cambarellus. The first 

 one has no representatives at all in the United States, while Cam- 

 barelhis has only one (in T>ouisiana). There remains a Mexican 

 species, C. 7viegiiiaiiiii, which has been placed with species of the true 

 subgenus Cambarus, but its position is quite uncertain, the male 

 copulatory organs being unknown. 



Carnegie Museum, 

 June lo, 1905. 



