156 BULLETIN NO. VII. 
tipped with reddish, and avery broad subterminal band of 
black, sometimes occupying the whole of the terminal third: 
Hab. Rocky Mountains between latitude 43° 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. Hab. Pacific Coast region from 
Northern California to Sitka, var. douglassi. 
Il. Tail-vertebree about four-fifths the length of head and 
body; tail, with hairs, rather longer than the body, generally 
full and bushy. Premolars } (1). Size large or medium. 
A. Premolars ? 
2. Above whitish-gray, varied with fulvous; beneath white; 
middle of back more or less brownish; indistinct fulvous lateral 
line; ears never conspicuously tufted. Hab. U. S. east of 
plains, Canada to Guatemala. S. carolinensis. 
Variety Jeucotis 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. 
8 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. Hab. 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. Hab. 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. Hab. South 
Atlantic and Gulf states. var. niger. 
(b). Smaller; nose and ears not white. Hab. 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. Hab. Mississippi basin. 
var. ludovicianus. 
III. Tail-vertebre alone equal to length of head and body; 
size large; premolars j. 
5. Above dark, pure grey, beneath white; tail black, washed 
with white. Hab. Pacific Coast west of Coast Range. 
S. fossor. 
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