PROC. ACAD. NAT. SCI. PHILA. 1915. 



PLATE IX. 



la 



lb 



2b 



4b 



V 



%^^ 



7a 



6a 



.<ri 



5a 



6b 



8 



7b 



5 b 



8a 



8b 



PILSBRY AND FERRISS: MOLLUSCA OF THE SOUTHWESTERN STATES. 



