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U. S. P. R. R. EXP. AND SURVEYS-ZOOLOGY—GENERAL REPORT. 
throughout, and all these phases of size and coloration have had different names assigned to 
them. 
The western fox squirrel is among the largest of the American species, being only exceeded 
by the fox squirrels of the'Atlantic States ; it is, however, a little smaller than the California 
gray squirrel. 
The head of this species is rather narrower than that of the Pennsylvania fox squirrel, S. 
cinereus , the muzzle longer and more attenuated, the ears higher, narrower, and projecting 
more above the fur of the nape. The hack of the ear is coated, generally, with compact short 
hairs, though sometimes these lengthen, especially in winter, so as to form slight tufts; there 
is also more or less of a woolly tuft adjacent to the base of the ear behind. 
The tail of this species is very long and ample, the vertebral portion shorter than the head 
and body ; with the hairs it is longer. In length of tail this species exceeds the S. cinereus. 
The feet are large, the soles naked in summer, more or less densely furred in winter, agreeing 
in this respect with nearly all the North American species. 
The colors of this squirrel, as already stated, vary very much, although the foxy type 
generally predominates. The most usual condition is a grizzled black gray and rusty above, the 
whole under parts of body and tail uniformly yellowish red, without any annulation. The 
lateral and superior hairs of the tail are, however, variously annulated. The shade of color in 
this respect varies very much. 
The more prominent varieties of the species are as follows : 
1. The typical coloration as described, with the under parts uniform foxy, &C. 1 
2. The colors above and on the tail as described ; the whole under surfaces, with the inside 
of the limbs, uniformly black, without annulation. (Nos. 179, Eacine ; 1983, Illinois ; 1346, 
St. Louis.) 
3. Similar to the preceding ; but the hairs of the under parts annulated with rusty, although 
the black greatly preponderates. (No. 2352, from Iowa.) 
4. A single specimen, No. 2300, received from Prairie Mer Kouge, with a number of fox- 
colored skins, exactly similar in all specific features, agrees perfectly with the description of S. 
auduboni, of Bachman, in having the upper parts more dusky, the belly of a dark chocolate 
brown, all the hairs annulated with black, as on the back. The hairs of the tail are more finely 
annulated than in the red variety. 
I have never seen any specimens of this species pure grizzled gray above, without a mixture of 
red or pure white beneath, as in S. vulpinus and cinereus ; nor, as in the former species, is the 
color, as far as my observations extend, ever entirely black, with the hairs unicolor to the roots, 
as in S. vulpinus. The species, therefore, does not present as great extremes in coloration as do 
the two others just mentioned. 
I am not prepared to say that there may not be two fox-colored squirrels in the Mississippi 
Valley, one more southern than the other ; hut investigations conducted mainly on dried 
specimens have not satisfied me that there are more than one. I have not the slightest doubt, 
1 A winter specimen from Fort Des Moines, Iowa, (2553,) has the fur much fuller and softer than in any others I have 
ever seen, with a peculiar tinge of purplish red beneath, especially on the tail. In a summer specimen from the same 
locality (2695) the color is a light yellow all over, paler beneath, the tips of the long hairs above nearly white. The hairs 
of the tail are of a darker shade or a yellowish rusty. All the caudal hairs, both above and below, are perfectly uniform 
to the roots, without any annulation whatever ; nor is there any annulation on the hack, the tips of the hairs only being 
lighter. 
