RODENTIA—SCIURINAE—SCIURUS CAROLINENSIS. "959 
separated the northern and southern gray squirrels from each other, mainly on account of the 
difference in size, and other characters, as given, With every disposition to rely implicitly on 
the judgment of this most excellent naturalist, I have been unable, after examining the very 
large series of specimens enumerated in the accompanying lists, to come to the same conclu- 
sion. I recognize, indeed, a larger size of the gray squirrel at the north than in the south ; 
but this is in accordance with the law so well ascertained in regard to nearly all our mammals 
and many of our birds that have an extensive northern and southern habitat at the same season 
of the year. Of the difference in habits I am unable to judge from want of personal experi - 
ence, but in all characters of external form, color, and proportions, I can find no features by 
which the gray squirrels of one region can be distinguished from those of another. In absolute 
size there is an appreciable difference between skins from extreme localities, and it is not a 
little remarkable that the very largest specimens come from the central portions of Iowa, where 
also the fox squirrels and the common gray rabbit have likewise the same superior magnitude 
to corresponding individuals from other regions. The variations in absolute dimensions are, 
however, very appreciable in specimens from the same locality, being quite as great as in picked 
specimens from different points. There is, however, no question of the greater average size of 
tlie gray squirrel in the north, and of its diminishing size as we procecd southward. I have 
accordingly selected a specimen from Washington, as the basis of the description, as furnishing 
a mean between the extremes. 
Not only have I felt constrained to unite the northern and southern gray squirrels as the 
same species, but a careful examination of a large number of specimens before me has convinced 
me that the supposed permanently black squirrel of the north is, in reality, only a black 
variety of the gray. I am not at present prepared to say whether the same animal passes 
through several stages of color until it becomes uniformly lustrous black, but the specimens at 
hand clearly exhibit a gentle gradation from the jet black to the pure gray. I may here 
remark, that the white tuft at the end of the tail of the black squirrel, as mentioned by Dr. 
Bachman, is far from constant, many more being without it than with it, 
A series of specimens now before me show very clearly the transition from the jet black color 
to the unquestionable gray. 
Ist. Color jet black throughout, even to the bases of the hairs of both surfaces. Not the 
slightest trace of annulation anywhere, even on the tail. A tuft of white hairs in the tip of the 
tail, as in the black foxes. Ears with very short hairs. Soles nearly naked. (No. 1276, 
Racine.) ' 
2d. Precisely similar to the last, save in the absence of the terminal white tuft to the tail. 
Soles even more naked. (No. 972, 9, West Northfield, Illinois.) 
3d. Precisely similar to the preceding above on the sides and in the tail. The hairs, how- 
ever, on the under surfaces, from the lower part of the neck to anus, are black, annulated faintly 
subterminally with yellowish brown. Soles naked. (No. 1057, Chicago.) 
4th. In this specimen the central line of the back alone is unmixed and uniform black to the 
bases of the hairs. The hairs of the tail show obsolete annulations of yellowish brown, only 
indistinctly clouding the black. The narrow subterminal annulations of the hairs on the upper 
part of the sides and sides of the back are less distinct and narrower than on the belly. (No, 
954, Racine, Wisconsin.) 
5th. In this specimen the brown annulation has invaded all the hairs of the back. Tips of 
the caudal hairs faintly washed with brown, but not distinctly annulated. The soles are quite 
