20 • A MANUAL OF AMERICAN LAND SHELLS. 



inces, and now inhabit most, if not all, of North America. They are 

 Zonites fulvus and Ferussacia suhcylindrica. 



Other species will probably be added to this list by further search ; • 

 among them Vallonia pulchella. 



In dealing with the species from the North in Eastern North America 

 see below, p. 26) the question of their distribution will be more fully 

 discussed. 



In addition to the species already enumerated as common to the whole 

 Pacific Province, there are many more restricted in their range. It ap- 

 pears that the Pacific Province is divided into two regions, (a) the Ore- 

 gonian and {b) Californian, the two intermingling slightly or overlapping 

 in the extreme north of California, near Humboldt Bay. The faunas of 

 these regions are nearly allied. 



(a) The Oregon Eegion lies between the Cascade Mountains and the 

 Pacific Ocean, extending northerly through British Columbia into 

 Alaska. 



The following species are peculiar to it : 



MacrocycUs HempMUi. Arionta Townsendiana. 



Micropliysa Lansingi. Avion foUolatus f 



Stearnsi. HemphUUa glandulosa. 



Mesodon devius. ' Succinea Haicldnsi. 



Aglaja fidelis. Onchidella borealis. 



There seems to be here some overlapping of the Pacific and Central 

 Provinces, as Arionta Townsendiana, Mesodon devius, and MacrocycUs 

 Vancouverensis extend along the mountains southeasterly into Idaho 

 and Montana. The former two become much dwarfed in size at their 

 most eastern range. 



(b) The Californian Eegion extends from Humboldt Bay to San Diego, 

 between the Sierra Nevada and Cascade Mountains on the east and 

 the Pacific Ocean on the west. 



The following are the species peculiar to it : 



MacrocycUs Toy ana. Limax Rewstoni. 



DnranU. Binneya notabiUs. 



Vitrina P/cifferi. ArioUmax GaUfornicus. 

 Zonites mutneyi. nigcr. 



conspectus. HemphiUi. 



chcrsvneUus, Andcrsoni. 



