684 MONOGRAPHS OF NORTH AMERICAN RODENTIA. 
Rocky Mountains], could not be distinguished from each other, except by 
the white belly of the latter. I consider it quite possible, if not very 
probable, that these may be two varieties of color of the same species.”* 
GEOGRAPHICAL DISTRIBUTION.—The habitat of Sciwrus hudsonius (includ- 
ing under this term its several varieties) embraces the greater part of the 
North American continent, extending northward to the limit of forest vegeta- 
tion and southward over the northern two-thirds of the United States. The 
eastern variety (subspecies hudsonius) has a far more extensive range than all 
of the others together; its habitat embracing nearly all of North America 
(north of about lat. 34°) east of the Rocky Mountains, and extending north- 
westward over most of Alaska. Its southern limit in the United States is 
quite irregular, terminating on the Atlantic coast near the Delaware Bay, 
but occupying the highlands of the interior as far southward as Northern 
Georgia and Northern Alabama, while one specimen in the collection of the 
National Museum is labelled as coming from as far south as Monticello, 
Miss. In the vicinity of Washington, D. C., it is occasionally found; I have 
lately seen a specimen from this locality, regarded as a rarity by the local 
collectors. In the Mississippi Valley, it is not common south of Central Illi- 
nois and Northern Missouri. Woodhouse, however, notes its occurrence 
in the Indian Territory. Northward, it is reported from Labrador and the 
region about Hudson’s Bay, and specimens are in the collection from as far 
north as Fort Anderson, the Yukon River, and Nulato. It extends westward 
to the eastern base of the Rocky Mountains. 
Subspecies richardsoni inhabits the Rocky Mountain region of Western 
Montana and Northern Idaho, ranging thence westward to the Cascade Range 
and northward considerably into British America, but to what distance is 
thus far not definitely known. Subspecies dowglassi occupies the Pacific 
coast from Central California northward to British Columbia, but is confined 
mainly to the narrow belt, west of the Coast Ranges. Its northern limit is 
not-yet known, but it ranges northward to Sitka, and probably to Southern 
Alaska. Subspecies fremonti occupies the more southern portion of the 
Rocky Mountains, from Southern Wyoming to. New Mexico, and thence 
westward over Utah, Southern Idaho, and Nevada to California. It is quite 
abundant in the mountains of Colorado, and there are also specimens in the 
collection from the Uintah Mountains. 
*Mamm. N. Amer. p. 277. 
