North American Helices. 

 Gen. XII. Iflacrocyclis Beck. 



Type. M. laxata Fer. 



vellicata Forbes concava Say. 



is Vancouverensis Lea. (planorboides Raf.) 



Vancouverensis Lea. 



C. Helicacea. 



Gen. Xy. Helix Linn. 

 2. MiCROPHYSA Albers. 



Type. H. Boothiana Pfr. 



minuscula Binn. incrustata Poey. 



vortex Pfr. 



5. Patula Held. 



Type. H. rotundata Mlill. 



perspectiva Say. mordax Sbuttl. 



striatella Anthon. isvar.of Cumberland iana Lea. 



exigiia Stimp. solitaria Say. 



Cumberlandiana Lea. strigosa Gould. 



alternata Say. sportella Gould 



is var. of Vancouverensis Lea. 



15. PoLYGYRA Say. 



Type. H. auriculata Say. 



cereolus Mublf. Ariadnse Pfr. ?j 



volvoxis Parr Hindsi Pfr. 



var, of septemvolva Say ? oppilata Mor. 



delitescens Shuttl. ventrosula Pfr. 



Troostiana Lea. hippocrepis Pfr. 



fatigiata Say (non Binn.)] auriculata Say. 



isfastigans L. W. Say. uvulifera Shuttl. 



* microdonta Desh. avara Say. 

 Texasiana Moric. 



* The habitats given ofH. microdonta are Key West and Bermuda. The Key 

 "West shell has been described by me (Annals VII. 138) as H. Carpenleriana. 

 The Bermuda shell has been distributed at JI. delitescens Shuttl. in Hit. ; it is, I 

 believe, H. microdonta Desh. 



