100 MONOGRAPH OF THE GENUS SCIURUS. 



ther. The northern grey sqnirrel has, as far as I have been 

 able to ascertain from an examination of many specimens, 

 permanently five grinders in each upper jaw, and the present 

 species has but four. Whether, at a very early age, the cat 

 squirrel may not, like the young fox squirrel, have a small 

 deciduous tooth, I have had no means of ascertaining ; all the 

 specimens before me having been obtained in autumn or win- 

 ter, and being adults, present the dental formula as given 

 above. The fox squirrel is permanently marked with white 

 ears and nose, which is not the case with the cat squirrel : 

 the former is a southern species, — the latter is found in the 

 middle and northern states. 



Description. — The head is less elongated than that of the 

 fox squirrel, the nose more obtuse ; incisors rather narrower, 

 shorter, and less prominent ; molars, with the exception of 

 their being a little smaller, bear a strong resemblance to, and 

 are similarly arranged to those of the former species. The 

 neck is short ; legs short and stout ; nails narrower at base 

 than those of the fox squirrel, shorter and less arched; the 

 tail also is shorter and less distichous ; the body, although 

 shorter is thicker, and the whole animal has a heavy, clumsy 

 appearance. The fur is not so soft as that of the northern 

 grey squirrel, but finer than that of the fox squirrel. 



This species, as well as the last, is subject to great varie- 

 ties of colour. I have observed in Peale's Museum speci- 

 mens of every shade of colour, from light grey to nearly black. 

 I have also seen two in cages which were nearly white, but 

 without the red eyes which form a characteristic mark in the 

 albino. There appears however to be this difference between 

 the varieties of the present species and those of the fox squir- 

 rel ; — the latter are permanent varieties ; scarcely any speci- 

 mens being found in intermediate colours: in the present 

 there is every shade of colour, scarcely two being found pre- 

 cisely alike. 



The most common variety however is the grey cat squirrel, 

 which I shall describe from a specimen now before me. 



Teeth orange ; nails dark brown near the base, lighter at 

 the extremities ; on the cheeks there is a slight tinge of yel- 

 lowish brown, extending to the neck at the insertion of the 

 head ; the inner surface of the ears of the same colour, the 

 outer surface of the fur on the ear, which extends a little 

 beyond the outer edge, and is of a soft woolly appearance, is 

 light cinereous edged with rusty brown ; whiskers black and 

 white, the former colour predominating. Under the throat, 

 the inner surface of the legs and thighs, and the whole under 

 surface, white ; on the back the fur is dark cinereous near 



