RODENTIA SCIURINAE SCIURUS CAROLINEWSIS. 259 



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 heen 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 

 the gray squirrel in the north, and of its diminishing size as we proceed 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. 



1st. 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 



