336 VERTEBRATE ANIMALS OF THE UNITED STATES 



E. epixanthum Brandt. Western porcupine. Similar to E. dor- 

 satum; tips of long hairs greenish yellow; midventral line brownish; 

 length 825 mm.; tail 165 mm.: from the upper Missouri into New 

 Mexico; westward to the Pacific; northward from Cahfornia to Alaska. 



Subspecies of E. epixanthum 



E. e. couesi Mearns. Smaller and paler: Arizona and New Mexico. 



Family 6. Aplodontiidae.- — Mountain beavers; boomers. Form 

 stout, heavy; limbs short; head broad, flat, triangular; tail short; eyes 

 very small; feet plantigrade, 5-toed; dentition i/i, 0/0, 2/1, t^Jt,'. 

 I genus. 



Aplodontia Richardson. With the characters of the family: about 

 4 species; burrowing, mainly nocturnal, animals which live in colonies 

 in dense wet forests, in which they construct numerous runways and 

 tunnels, and feed on bark, leaves and twigs, laying up large stores for 

 winter use; they raise 2 or 3 young annually and do not hibernate. 



A. major Merriam. Color grizzled grayish brown; belly gray; 

 whiskers black; length 375 mm.; tail t,2> mm.; hind foot 62 mm.: Sierras 

 in Placer County, California. 



Subspecies of A . major 



A. m. rainieri Merr. Color paler; whiskers white: Mount Rainier, 

 Washington. 



A. rufa (Rafinesque) . Color umber; belly gray; whiskers white; 

 length 340 mm.; hind foot 53 mm.: Cascades of the Columbia River. 



A. pacijica Merr. Color fulvous brown; belly plumbeous; length 

 304 mm.; tail 22 mm.; hind foot 48 mm.: Yaquina Bay, Oregon. 



A. phea Merr. Color uniform bister brown; length 330 mm.; tail 

 30 mm.; hind foot 55 mm.: Marin County, California. 



A. olympica Merr. Similar to A. rufa, but darker and larger; 

 length 350 mm.; tail 35 mm.; hind foot 55 mm.: Olympic Mountains, 

 Washington. 



Family 7. Sciuridae.- — Squirrels, marmots, etc. Arboreal or ter- 

 restrial rodents, with mostly long, bushy tails; skull with postorbital 

 processes; molars rooted and with tubercular biting surfaces: 15 or 20 

 genera and about 250 species; cosmopolitan, except in the Australian 

 region; about 9 genera and 90 species in the United States and Canada. 



Key to the United States Genera of Sciuridae 



ai Sides of body without flying membrane, 

 bi Body slender and graceful; tail long. 



