NORTH AMERICAN LAND MAMMALS. 217 



t*Microtus montanus rivularis (Bailey). 



1898. Microtus nevadensis rivularis Bailey, Proc. Biol. Soc. 



Washington, vol. 12, p. 87. April 30, 1898. 

 1900. Microtus montanus rivularis Bailey, North Amer. Fauna, 



No. 17, p. 29. Juno 6, 1900. 

 Type Locality. — St. George, Washington County, Utah. 

 Kange. — KnowTi only from type locality; probably restricted to 



lower Sonoran zone. 



t*Microtus nanus nanus (llerriam). 



1891. Arvicola {Mynomes) nanus Merriam, North Amer. Fauna, 

 No. 5, p. 63. July 30, 1891. 



1897. Microtus nanus Miller, Proc. Biol. Soc. Washington, 

 vol. 11, p. 67. April 21, 1897. 



Type Locality. — Pahsimeroi Mountains, Idaho. Altitude, 



9,350 feet. 

 Range. — Rocky Mountains and outlying ranges, from central 



Idaho southward to central Nevada and southern Colorado, 



in Canadian zone. 

 t*Microtus nanus canescens Bailey. 



1898. Microtus nanus canescens Bailey, Proc. Biol. Soc. Wash- 

 ington, vol. 12, p. 87. April 30, 1898. 



Type Locality. — Conconully, Okanogan County, Washington. 

 Range. — Northern Washington and southern British Columbia, 



east of the Cascades. Apparently confined to the transition 



zone. 

 t*Microtus canicaudus Miller. 



1897. Microtus canicaudus Miller, Proc. Biol. Soc. Washing- 

 ton, vol. 11, p. 67. April 21, 1897. 



Type Locality. — McCoy, WUlamette Valley, Polk County, 



Oregon. 

 Range. — WUlamette Valley, Oregon, and the east base of the 



Cascades in southern Washington, in transition zone. 

 t*Microtus dutcheri Bailey. 



1898. Microtus dutcheri Bailey, Proc. Biol. Soc. Washington, 

 vol. 12, p. 85. April 30, 1898. 



Type Locality. — Big Cottonwood Meadows, near Mount 



Whitney, Tulare County, California. Altitude, 10,000 feet. 

 Range. — Hudsonion zone of the southern Sierra Nevada. 

 t*Microtus nevadensis Bailey. 



1898. Microtus nevadensis Bailey, Proc. Biol. Soc. Washington, 



vol. 12, p. 86. April 30, 1898. 

 Type Locality. — Ash Meadows, Nye Coimty, Nevada. 

 Range. — Kjiown only from the type locality and Pahranagat 



Valley, about 100 miles to the northeast. Both localities are 



in the lower Sonoran zone. 



