196 BULLETIN OF THE 



this accumulation of facts is here briefly offered. It must be studied 

 in connection with the chapters referred to, and also with the text-book 

 of our land shells, prepared for the Smithsonian Institution by my 

 friend, Mr. Bland, and myself.* 



The regions west of the Rocky Mountains have become known since 

 the publication of my father's work, and much additional information 

 received from the eastern portion of the continent. It becomes neces- 

 sary, therefore, somewhat to modify the limits of the sections which he 

 indicated. I have already suggested f that, in regard to the geograph- 

 ical distribution of the Terrestrial Pulmonata of North America, there 

 appear to be three distinct faunas, which I have called, — 



I. The Pacific Province. 



II. The Central Province. 



III. The Eastern Province. 



The boundaries of these provinces and the subdivisions which appear 

 to exist in them will be given below, as well as lists of their peculiar 

 species. It must be distinctly understood, however, that future re- 

 searches, especially at the South and Southwest, may greatly modify the 

 views here presented. 



I. The Pacific Province comprises a narrow strip between the 

 Sierra Nevada and Cascade Mountains on the east, and the Pacific 

 ( >cean on the west. Its southern limit is San Diego, from whence it 

 extends northerly into Alaska. 



Over this province the following species range : — 



Macrocyclis Vancouverensis. Ariolimax Columbianus. 



sportella. Prophysaon Hemphilli. 



Helix Columbiana. Succinea rusticana. 



germana. Oregonensis. 



tudiculata. Nuttalliana. 



Over the whole of this province we find also the following species, 

 common to Eastern North America. They also extend over the whole 



northern portion of the continent, where the mountains have ceased to 



* Land ami Freshwater Shells of North America, Part I. Pulmonata Geophila. 

 By W. G. Binney aid Tin. mas Bland, Washington, 1869. 

 t Proc. Bo>t. Sue. Nat. Hi-:., IX. 177, 1863. 



