156 BULLETIN NO. VII. 



tipped with reddish, and a very broad subterminal band of 

 black, sometimes occupying the whole of the terminal third- 

 Hob. Rocky Mountains between latitude 43 C and 52", and thence 

 westward to the Cascade Range. var. richardsoni. 



(c. ) Much as above, tail with less black, more or less tinged 

 with fulvous or rufous below. Hob. Pacific Coast region from 

 Northern California to Sitka, var. douglassi. 



II. Tail- vertebras about four- fifths the length of head and 

 body; tail, with hairs, rather longer than the body, generally 

 full and bushy. Premolars f ({). Size large or medium. 



A. Premolars f 



2. Above whitish- gray, varied with fulvous; beneath white; 

 middle of back more or less brownish; indistinct fulvous lateral 

 line; ears never conspicuously tufted. Hob. U. S. east of 

 plains, Canada to Guatemala. 8. carolinensis. 



Variety leucotis is the familiar form with the body longer 

 than ten inches. The type of the species is smaller and inhab- 

 its the South Atlantic states, while variety yucatanensis is still 

 smaller and has no rufous suffusions. 



3. Above dark bluish-grey, a dorsal band of bright chestnut; 

 a distinct black lateral line; no fulvous suffusions; below white;, 

 ears very large, tufted, frequently melanistic. Hob. Rocky 

 Mountains of Colorado and Arizona. S. alberti. 



B. Premolars }. 



4. Color above generally some shade of grey, but extremely 

 variable; rusty and melanistic phases prevalent; size large; 

 tail broad and bushy. Hdb. E. U. S. to the plains. S. niger. 



(a). Length 13 inches; nose and ears white; below gener- 

 ally fulvous or rufous; dusky phases frequent. Hob. South 

 Atlantic and Gulf states. var. niger. 



(b). Smaller; nose and ears not white. Hob. North Atlantic 

 states. var. cinereus. 



(c). Above dusky grey, strongly suffused with rufous; ears, 

 feet and ventral surface fulvous, varying to rufous; occasion- 

 ally dusky or black beneath. Hob. Mississippi basin. 



var. ludovicianus. 



III. Tail- vertebrae alone equal to length of head and body ; 

 size large; premolars f. 



5. Above dark, pure grey, beneath white; tail black, washed 

 with white. Hal). Pacific Coast west of Coast Range. 



8. fossor. 



