266 NORTHERN GRAY SQUIRREL. 



ones have a sharp cutting edge, and are chisel-shaped ; the lower are 

 much longer and thinner. The anterior grinder, although round and 

 small, is as long as the second ; the remaining four grinders are consider- 

 abl)- more excavated than those of the cat-squirrel, presenting two trans- 

 verse ridges of enamel. The lower grinders corresponding to those above 

 have also elevated cro\vns. 



The hair is a little softer than that of the cat-squirrel, being coarsest 

 on the forehead. 



Nose, rather obtuse ; forehead, arched ; whiskers, as long as the head ; 

 ears, sharply rounded, concave on both sides, covered with hair ; on the 

 outside the hairs are longest. In winter the fur projects upward, about 

 three lines beyond the margin ; in summer, however, the hairs covering 

 the ears are very short, and do not extend beyond the margin. 



This species appears under many varieties ; there are, however, two 

 very permanent ones, which we shall attempt to describe. 



1st, Gray variety. — The nose, cheeks, a space around the eyes extend- 

 ing to the insertion of the neck, the upper surface of the fore and hind- 

 feet, and a stripe along the sides, yellowish-brown ; the ears on their 

 posterior surface, are in most specimeas brownish-yellow ; in about one 

 in ten they are dull white, edged with, brown. On the back, from the 

 shoulders there is an obscure stripe of brown, broadest at its commence- 

 ment, running down to a point at the insertion of the tail. In some 

 specimens this stripe is wanting. On the neck, sides, and hips, the colour 

 is light gray; the hairs separately are for one half their length dark 

 cinereous, then light umber, then a narrow mark of black, and are tipped 

 with white ; a considerable number of black hairs are interspersed, 

 giving it a yellowish-brown colour on the dorsal aspect, and a light gray 

 tint on the sides ; the hairs in the tail are light yellowish-brown from 

 the roots, with three stripes of black, the outer one being widest, and 

 broadly tipped Mnth white ; the whole under surface is white. The above 

 is the most common variety. 



There are specimens in which the yellowish markings on the sides 

 and feet are altogether wanting. Dr. Godman, (vol. ii., p. 133.) supposed 

 that the golden colour of the hind-feet is a very permanent mark. The 

 specimens from Pennsylvania in our possession, and a few from the 

 Upper Missouri, have generally this peculiarit)^ but many of those from 

 New York and New England have gray feet, without the slightest mix- 

 ture of yellow. 



2d, Black variety. — This we have on several occasions seen taken 



