OZ A MANUAL OF AMERICAN LAND SHELLS. 



above as spreading- southwardly from the Northern Regiou equally on 

 both sides of the Sierra Nevada and Eocky Mountains. These species 

 may be said to inhabit the whole continent of North America as far 

 south as Mexico. The range of some is still greater. Thus, Zonites 

 minusculus has been found from British Columbia to Labrador on the 

 north, to Yucatan and Florida on the south, and still farther in Cuba, 

 Jamaica, Porto Eico, and Bermuda. StroMla lahijrinihica also is found 

 over all Eastern North America, and perhaps in Mexico (as H. Strebeli, 

 see Fischer and Crosse, Moll. Mex. et Guat., 267). It is also by some 

 considered identical with an Eocene fossil of France and England; 

 (See below.) Zonites arbor eus ranges from Labrador to New Mexico, 

 and in Nevada and California, and from British Columbia to Florida, 

 Cuba, and Guadaloupe. Vertigo ovata is found from Maine to Mexico 

 and in Cuba. 



The character of the soil and climate, with, perhaps, the gradual ele- 

 vation, is such as to render the land shells rare, if not quite extinct, 

 before the Eocky Mountains are reached, the western boundary of the 

 Interior Eegion. But one species, Patula soUtaria, seems to have passed 

 this mountain-barrier into the Central Province. This is found with 

 P. Cooperi in Montana and Idaho, and is very difficult to distinguish 

 from forms of the last species. It is, however, ovii^arous (from Salmon 

 Eiver, Idaho), while P. strigosa, Cooperi, HempMlli, and Idahoensis are 

 viviparous. It has also passed into the Pacific Province at the Dalles. 



The following list contains the names of all the species inhabiting the 

 Interior Eegion, including those which have spread into it from the 

 Northern Eegion : 



Macrocyolis concava. Zonites fulvus. 

 Zonites fuliginosus. gularis. 



friahilis. suppressus. 



Icevigatus. internus. 



ligerus. Limax campestris. 



intertextus. Patula soUtaria. 



inornatus. alternata. 



nitidus. perspectiva. 



arhoreiis. striatella. 



viridulns. Helicodiscus Uneatus. 



indenfatus. StroMla lahyrinfJiica. 



limatulus. Polygyra Dorfeuilliana. 



minusculus. lcj)orina. 



