MAMMALS 303 



R. m. dychei Allen. More black on the upper parts; tail shorter: 

 eastern Iowa and Missouri to central Colorado and Wyoming; north- 

 ward to North Dakota. 



R. m: nigrescens Howell. Under parts more blackish: eastern 

 Washington, Oregon and northern Cahfornia and western Idaho. 



R. m. longicaudus (Baird). Colors darker; length 152 mm.; tail 

 75 mm.; hind foot 17 mm.: western California, west of the Sierras. 



R. catalincB Elliot. Similar to R. m. longicaudus, but larger; length 

 169 mm.; tail 94 mm.: Santa Catalina Island. 



R. raviventris Dixon. Upper parts very dark; under parts pinkish; 

 length 130 mm.; tail 64 mm.; hind foot 16 mm.: salt marshes of San 

 Francisco Bay. 



Subspecies of R. raviventris 



R. r. raviventris Dix. Southern part of San Francisco Bay. 



R. r. halicoetes Dix. Size larger; length 156 mm.; under parts white: 

 salt marshes of San Pablo, Suisan Bay and the lower San Joaquin and 

 Sacramento Rivers. 



R. fulvescens Allen. Color buff above, white beneath; length 183 

 mm.; tail 102 mm.; hind foot 19 mm.: Mexico and southern States. 



Subspecies of R. fulvescens 



R. f. intermedins Allen. Color pale: southern Texas. 

 R.f. aurantius Allen. Color darker: eastern Texas and Oklahoma, 

 southern Arkansas and Louisiana west of the Mississippi. 



Fig. 163. — Hind foot of Peromyscus leucopus, showing the plantar tubercles {from Howell). 



3. Peromyscus Gloger. Wood mice; deer mice; vesper mice; 

 white-footed mice. Body small and slender; tail long, being a third or 

 a half the total length; eyes and ears large; internal cheek pouches 

 present; hind feet and legs long, the former with 6 plantar tubercles 

 (Fig. 163): about 100 species, all North American; about 15 species 

 in the United States, with many subspecies; nocturnal animals which 

 live on the ground in a great variety of situations, feeding principally 

 on grains and seeds. They do not form permanent runways, although 

 they may use those of other animals. They breed throughout the year, 

 raising from 4 to 6 in a litter, and do not hibernate, and may exceed in 



