1909.] NATURAL SCIENCES OF PHILADELPHIA. 515 



Bifidaria quadridentata Sterki. 



Wickersham's, Miller Canyon. One specimen. 



Bifidaria ashmuni Sterki. 

 Ash Canyon. 



Bifidaria cochisensis Pils. and Ferr. 



Tanner Canyon, abundant. This form and the following will be 

 described in the next paper of this series, in connection with a general 

 review of the group of B. ashmuni. 



Bifidaria cochisensis oligobasodon Pils. and Ferr, 



Ash Canyon. 



Bifidaria pilsbryana Sterki. 



Wickersham's, Miller Peak. 



Bifidaria tappaniana (C. B. Ad.). 



Tanner Canyon, 6,000 feet; also San Pedro drift at Benson. 11 



Vertigo ovata Say. 



Ash Canyon; Tanner Canyon, 6,000 feet; also San Pedro drift at 

 Benson. 



Vertigo modesta parietalis Anc. 



Wickersham's, Miller Peak. 



Vertigo conoinnula Ckll. 



Wickersham's, Miller Peak; one immature shell. 

 Vertigo milium Gld. 



Tanner Canyon, 6,000 feet; drift of San Pedro river at Benson. 



FERUSSACID^J. 

 Cochlicopa lubrioa (Mull.). 



Tanner Canyon, 6,000 feet; Carr Canyon; Wickersham's, Miller Peak. 



LYMN^ID^]. 



Lymnaea parva Lea. 



Ash Canyon; a few very young specimens. 



PHYSID^J. 



Physa virgata Gld. 



Small, slender, long-spired examples, clearly of the virgata type, were 

 taken in Tanner Canyon, in a spring at about 6000 ft. 



11 Bifidaria pentodon (Say) was taken in San Pedro drift at Benson, Cochise 

 •county, Arizona. 



