PLATE 7. 



-Camharus hageiiiarnis Faxon. Muldon, Miss. Gonopod of &. form I. la, outer side, lb, 

 inner side, Ic, front. 



- Camharus peUucidus (TeWkamYji). Mammoth Cave, Ky. Gonopod of o^, form I. 2o, outer 

 side, 26, inner side, 2c, front. 



- Cambarus t<alidusFa,xoii. Huntsville, Ala. Type. M. C. Z., No.301. Gonopod (cf form I.). 

 3a, outer side, 3b, inner side, 3c, front. 



- Cambarus validits Faxon. Type. Antenna! scale. 



- Astacus nigrescens fortis Faxon, cf. Fall R., Fall City Mills, Cal. Type. U. S. N. M. 

 Antennal scale. 



Fig. 6. — Ast<icus gambeliconnedensFaxon. cf. Snake R., Upper Salmon Falls, Idaho. Type. U.S. 



N. M., No. 23,096. Antennal scale. 

 Fig. 7. — Cambarus hagenianus Faxon. 9 • Muldon, Miss. Annulus ventralis. 

 Fig. 8. — Cambarus validus Faxon, cf. Type. Epistoma. 

 Fig. 9. — Astacus nigrescens fortis Faxon, cf. Type. Epistoma. 

 Fig. 10. — Astacus gambcUi conriectens Faxon, cf- Type. Epistoma. 



