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U. S. P. R. R. EXP. AND SURVEYS—ZOOLOGY-GENERAL REPORT. 
satisfied me that the peculiar annulation of the under fur is either a condition of the winter 
fur or else indicates a more or less permanent variety, such as the squirrels are so subject to. 
This is also the opinion of Dr. Cooper, who is very familiar with the living animal. The 
description of the supposed species, as prepared at the time, will he found in the accompanying 
foot note. 1 
The changes with season would then he as follows: 
In summer, the color beneath is of a uniform bright rusty or tan color, the hairs without any 
annulation whatever. The ears are more or less tufted, with long hairs growing from their 
dorsal surface. The soles are hairy to the posterior third, the region behind the tubercles being 
naked. This character, however, as well as that of the tufts on the ears, varies with the speci¬ 
men in those killed in the same season. 
In winter, especially about Puget’s Sound, the fur becomes much fuller and softer, the tufts 
on the ears increase, the soles become densely hairy to the very bases of the large tubercles at 
the roots of the toes, the colors beneath are much more cinereous, and, in most cases, the hairs 
are tipped or annulated subterminally with dusky. The upper surfaces of the hind feet have 
lost their bright and uniform rufous color by a mixture of black. The tail appears to undergo 
little change. 
1 Sciurus suckleyi.—Sp. Ch.— Larger than S. hudsonius. Tail much shorter than the body ; very flat. Ears tufted. 
Under surface of feet densely clothed with hair to the bases of the toes. Fur full and soft. 
Above, mixed chestnut, brown, and black ; beneath, ferruginous, with hairs intermixed of black and black and rusty 
annulated. A dusky line along the sides. Tail black at the end, margined laterally all round with rusty white; the hairs 
annulated, except at tip, with chestnut and black, like the back ; (lighter below.) 
Size larger than that of S. hudsonius, to which it is closely allied in characters. The head is short and broad; the 
whiskers black and longer than the head. The ears appear shorter than they really are from being in a measure buried by 
the long fur of the back ; that between the ears being nearly half an inch long. The interior surface or concavity thickly 
covered with short hairs ; the exterior coated with soft long hairs ; these, near the upper margin, projecting beyond it to 
the extent of four lines in a flattened tuft. Fur everywhere fuller, longer, and softer than in other species examined. 
Tail much flattened, though not broad ; considerably shorter than the body. Extremities not long; on the fore foot the 
third toe is longest; the second scarcely shorter ; second a little longer than fifth or exterior ; palms naked. On the hind 
feet the third and fourth toes are about equal ; the fifth reaches to their claw ; the claw of the first extends beyond the 
base of that of the fifth. The sole is entirely hairy to the base of the toes, the under surface of the tarsus being densely 
covered ; and the hairs on the outside of all the extremities generally longer and fuller than usual, not lying close pressed 
as in most other species. 
Above and on sides, including two-thirds of the tail, is a finely mixed black and rusty brown, or chestnut brown, much 
as in S. douglassii. Beneath, the hairs are of a dull ferruginous or buff, mixed with others either black or annulated 
black and rusty. This is only visible, however, when examined closely, and at a short distance the general impression is 
that of a dull ferruginous. The chin, sides of the snout, and a ring round the eye are purer ferruginous. The outer surfaces 
of the feet are grizzled, rusty, and black, nowhere of the uniform tint of other species. There is a dusky line on the 
flanks, separating the colors of the sides from those of the belly ; this appears to run more into the belly posteriorly than 
usual. 
The tail, as already stated, is very much flattened, though narrow ; in shape not much unlike that of Pteromys, though 
not so soft. The upper surface is much like the back, though with a brownish chestnut tinge and coarser annulations. 
It is black at the extremity and margined all round (sides and tip) with rusty white, darkest on the latter. The single 
hairs at the tip of the tail are black, except at the extremities ; those on the rest of the tail are dark brown or brownish 
lead color at the base, and annulated with black and dull chestnut, (brightest above ;) these mixed with hairs almost 
entirely black. All those on the sides of the tail are tipped with rusty white. 
This species is readily distinguishable from its nearest ally, S. douglassii, by the softer and longer fur ; more flattened tail, 
hairy soles, and the mixture of black and annulated hairs on the under parts, a feature rarely observed in other species. 
S. mollipilosus has no dark line on the sides ; no tufts to the ear ; the middle of abdomen is cinereous, not ferruginous ; the 
tail is longer and not so much flattened. The tail is without the continuous rusty white border. S.fuliginosus, Bach., from 
Louisiana, is said to exhibit the annulations of the hairs below ; but the prevailing color there is brownish ; the prevailing 
color of the tail, black above ; the ears are clothed with short hair ; there is no dusk}' stripe on the side, nor a rusty 
white border to the tail; the geographical distribution, too, is very widely remote. P. lanuginosus agrees in character of 
fur as to softness and length, but it has the feet entirely hairy to the claws ; the under parts, too, are pure white, witli 
other differences. 
