4 THE NAUTILUS. 



P. sterri Voith. (?) Rocky Mountains. 



P. sp. Rocky Mountains. 



P. sterkiana Pilsb. South (and Lower) California. 



P. syngenes Pilsb.' Arizona. 



Subg. Leucochila Alb. & Mart. 



P. fallax Say. All east and S. W. to Arizona. 

 P. modica Gld. Ga., Fla. 



Subg. Columella Mart. (Edentulina Cless.). 



P. edentula Drp.^ (simplex Old.). All N. A. except southwest. 

 V. alticola Ing. Rocky Mts. 

 var. . Wash., Alaska. 



Subg. BIfidaria Sterki.* 



Sect. . 



P. arizonensis (Gabb) W. G. B. Colo., N. M., Ariz. 



V. saxicola Ckll. Colo. 

 P. corticai'ia Say. E. of Rockies, except extreme south. 



Sect. Albinula Sterki. 



P. armifera Say. All N. A. 

 P. contracta Say. All N. A. East of Rockies. 

 P. holzingeri Sterki. Ohio to Manitoba, N. M., Kas. 

 V. fordiana Sterki. Kas. 



Sect. Bifidaria s. str. 



P. hordeacea Gabb. Tex. to Ariz. 



P. procera Gld. R. I. to Minn., S. C. to Tex. 



P. hordeacella Pilsb. Fla. to Ariz. 



P. rupicola Say. S. C. and Fla to La. 



P. servilis Gld. La. ? 



P. (riograndensis Sterki mss.). Hidalgo, Tex. 



Sect. Vertigo psis Ckll. mss. 



P. pilsbryana Sterki. N. M., Ariz. 



P. curvidens Gld.' All N. A. east of Rockies. 



V. gracilis Sterki. R. I., Ohio, Tenn. 



V. floridana Dall. Fla. 

 P. pentodon Say. All N. A. east of Rockies. 



