_Distribution._--From the eastern base of the Cascade Mountains westward to the Pacific. Marginal occurrences are: Nooksack River (Taylor and Shaw, 1929: 18), Lake Wenatchee (W. W. D.) and Wenatchee (Taylor and Shaw, 1929: 18). _Remarks._--Squirrels from the Puget Sound area are slightly less intensely colored than specimens from the ocean coast and the Olympic Mountains. Those from the higher and eastern Cascade Mountains are paler still. When, however, squirrels from the Cascades of Washington are compared with individuals of the race inhabiting the Cascades of Oregon, it is apparent that the Washington squirrels are nearest to _douglasii_. The pale tips of the hairs in the tail of the Oregon race are strikingly white while in Washington specimens they are orange or yellow. The Douglas squirrel resembles the red squirrel in size and proportions but differs in being dusky olive (less reddish) on the upper parts and orange instead of white on the underparts. Douglas squirrels range from southern British Columbia southward to Lower California. They are confined to the Pacific Coastal region. Although closely related to _Tamiasciurus hudsonicus_, no intergradation with that species has been found. The rich coloration of the Douglas squirrel matches the background of the humid forests it inhabits. It occurs at sea level along the ocean coast, the shores of Puget Sound and on some islands in Puget Sound. It ranges through the Transition and Canadian life-zones well into the Hudsonian. It makes its home in holes in trees or in nests constructed of conifer twigs, needles and bark. Old nests of birds may be modified and taken over, but most outside nests seem to have been made entirely by the squirrel. Nests are usually placed near the top of denser fir and cedar trees. Nests are hemispherical in shape, 12 inches or more in diameter, and open on top. The central cup, 4 inches in diameter, is lined with strips of inner bark of red cedar coiled but unshredded. Nests in holes are usually some distance from the ground, but the entrances to some are at ground level. The habits of the Douglas squirrels vary with the season. In spring they are shy. They rarely call and are skillful in keeping branches or tree trunks between themselves and persons. In June and July they become bolder, calling more frequently and moving about more. In September and October they become exceptionally bold. They call almost incessantly from late morning until early afternoon, and spend considerable time on the ground.