80 
U. S. P. R R EXP. AND SURVEYS — 47TH PARALLEL. 
The only difference in the color of the male and female seems to he a deeper hue of the 
orange colored under parts of the latter. 
Length from nose to tip of tail, 14 inches. 
PTEROMYS OREGONENSIS, Bach. 
Columbia River Flying Squirrel. 
Pteromys oregonensis, Bachman, Jour. Acad. Nat. Sc. Phila. VIII, 1839, 101.— Ib. in Townsend’s Narrative, 1839. 
Aud. & Bach. N. Am. Quod. I, 1849, 133 ; plate x 
Baird, Gen. Rep. Mammals, 1857, 290. 
Sp. Ch. —Much larger than Pteromys volucella. Tail, with hairs, longer than the body alone ; shorter than head and body. 
Plying membrane very broad, its antero-external corner exhibiting a conspicuous angle. Color above yellowish brown, beneath 
dull white ; the hairs plumbeous at base. Tail becoming more plumbeous towards the tip. Length, 7 inches ; tail with hairs, 
6j ; hind foot, lg inches. 
The only specimens I ever saw were obtained in August, near the foot of Mount St. Helens. 
In turning over a log, a nest was found under it containing four young, still blind. The mother 
in attempting to escape was killed by a pistol ball, and was lost before I could see it. It was 
much larger than the P. volucella of the eastern States. I never heard of one having been seen 
in the country nearer the coast, and think it is confined to the mountains. 
TAMIAS TOWNSENDII. 
Townsend’s Striped Squirrel. 
Tamias townsendii, Bachman, Jour. Phila. Acad. Nat. Sc. Phila. VIII, i, 1839, 68 .—Ib. in Townsend’s Narrative, 
1839, 321. 
Aud. & Bach. N. Am. Quad. I, 1849, 159 ; pi. xx. 
Baird, Gen. Rep. Mammals, 1857, 301. 
Tamias cooperii, Baird, Pr. Ac. Nat. Sc. Phila. VII, April, 1855, 334. 
Sp. Ch —Larger than T. striatus. Tail, with hairs, nearly or quite as long as the body. Sides of head striped. Above and 
on the sides rufous brown, with five dark stripes reaching to the tail, the intervals between which are scarcely or but seldom 
paler than the ground color; beneath, dull white. Ears dusky brown, hoary posteriorly. Tail bright chestnut beneath, 
margined with ashy white, within which is a band of black. Length 5 to 6 inches! Hind foot 1.40 to 1.50. 
Varies in rather paler colors, ash-colored interspaces, and sometimes the back with black hairs interspersed, so as to obscure 
or nearly conceal the dorsal stripes 
The ground squirrel, or “ chipmunk,” inhabiting the neighborhood of the coast in Washington 
Territory, resembles closely in its habits that common on the Atlantic border. It differs, however, 
considerably in colors, and has not the shrill cry of the eastern species. About the first of 
April it emerges from its winter nest and soon after great numbers are seen where none appeared 
before. In summer they will often sit on some prominent stump or rock, and make a shrill 
barking noise for hours together, answering each other from distant parts of the woods. They 
become very mischievous in the garden, being especially fond of peas either green or ripe, for 
which they will come from their burrows several rods distant, as I have observed from the scattered 
pea-vines growing along the path where they have dropped the seed from their overloaded cheek- 
pouches. In November they retire to their burrows to sleep through the long rainy season, 
though it is probable that in the warm weather, often occurring in the winter of this coast, they 
come out to breathe the fresh air from time to time. 
The ground squirrels obtained on the summit of the Cascade mountains differ in some respects 
from those near the coast. As I observed these animals in abundance in all the wooded regions, 
and saw no marked differences in their appearance or habits, I supposed all to be of one species, 
varying slightly in size and colors from differences of climate, which, between the perpetual 
