MAMMALS ^ 309 



M. m. macrurus (Merr.). Larger and darker: coastal region of 

 Washington, and northwards to Alaska. 



M. angusticeps Bailey. Color dark brownish gray, darkest on the 

 face; tail distinctly bicolor; length 170 mm.; tail 56 mm.; hind foot 22; 

 skull very narrow: coastal region of northwestern California and 

 southern Oregon. 



M. montanus (Peale). Color dark gray; belly whitish; length 175 

 mm.; tail ^2 mm.; hind foot 21 mm.: eastern Oregon; northern Cali- 

 fornia to Nevada. 



Subspecies of M. montanus 



M. m. arizonensis Bailey. Color more ferrugineous: eastern 

 Arizona; Transition zone. 



M. m. rivularis (Bailey). Larger and lighter colored: Washington 

 County, Utah; Lower Sonoran zone. 



M. nanus (Merr.). Color grizzled gray; length 151 mm.; tail 41 

 mm.; hind foot 18 mm.: Rocky Mountains from central Idaho to 

 central Nevada and southern Colorado; Canadian zone. 



M. n. canescens Bailey. Color lighter and clearer: northern Wash- 

 ington and British Columbia, east of the Cascades. 



M. canicaudus Miller. Color bright yellowish brown; belly whitish 

 gray; tail uniform grayish; length 135 mm.; tail t^t^ mm.; hind foot 20 

 mm.: Willamette Valley and southern Washington; Transition zone. 



M. dutcheri Bailey. Color dark brown; belly bulYy brown; tail 

 bicolor; length 167 mm.; tail 35 mm.; hind foot 20 mm.: Hudsonian 

 zone of the southern Sierras; in wet alpine meadows. 



M. richardsoni (DeKay). Color grayish sepia; belly whitish; tail 

 long; feet large; fur long and heavy; length 234 mm.; tail 81 mm.; 

 hind foot 29 mm.: Boreal zones of the Rockies and the Cascades. 



Subspecies of M. richardsoni 



M. r. macro pus (Merr.). Color dark sepia; size smaller: Rockies 

 from the Wasatch into Canada. 



M. r. arvicoloides (Rhoads). Color dark sepia: Boreal zone of the 

 Cascades. 



M. mogollonensis (Mearns). Color dull rusty brown; belly cinna- 

 mon or gray; mammas 4; length 131 mm.; tail 28 mm.; hind foot 18 

 mm. : plateau country of central Arizona. 



M. oregoni (Bachman). Color dark brown and grizzled; belly 

 dusky; length 140 mm.; tail 42 mm.; hind foot 17 mm.: Pacific 



