90 MAMMALIA. 



gnawing. The molars also have flat crowns, whose enamelled 

 eminences are always transverse, so as to be in opposition to the 

 horizontal motion of the jaw, and to increase the power of tritu- 

 ration. 



The genera in which these eminences are simple lines, and the 

 crown is very flat, are more exclusively frugivorous; those in which 

 the eminences of the teeth are divided into blunt tubercles are om- 

 nivorous; while the small number of such as have no points more 

 readily attack other animals, and approximate somewhat to the 

 Carnaria. 



The form of the body in the Rodentia is generally such, that the 

 hinder parts of it exceed those of the front; so that they rather leap 

 than walk. In some of them this disproportion is even as excessive 

 as it is in the Kanguroos. 



The inferiority of these animals is visible in most of the details of 

 their organization. Those genera however which possess stronger 

 clavicles have a certain degree of dexterity, and use their fore feet 

 to convey their food to the mouth. 



Some of them even climb with facility: such is the 



SCIURUS, Lin. 



Squirrels are distinguished by their strongly compressed inferior incisors, 

 and by their long tail furnished with hairs. They have four toes before, 

 and five behind. The thumb of the fore foot is sometimes marked by a tu- 

 bercle. They have in all four grinders, variously tuberculated, and a very 

 small additional one above in front, that very soon falls. The head is large 

 and the eyes projecting and lively. They are light and active animals, 

 living on trees, and feeding on fruits. 



SCIUHUS, Cuv, 



In the Squirrel, properly so called, the hairs of the tail are arranged on 

 the sides, so as to resemble a feather. There are a great many species in 

 the two continents. 



Sc. vulgaris, Buff. (The Common Squirrel.) The back of a lively red; 

 belly white; ears terminated by a tuft of hair. Those of the north, in win- 

 ter, become of a beautiful bluish ash colour, producing the fur called min- 

 ever when taken only from the back, and vair (by the French) when it 

 consists of the whole skin. 



The American species have no pencils to their ears. Such are 



Sc. rinereus, L. (The Grey Squirrel of Carolina.) Larger than that of 

 Europe; ash coloured, with a white abdomen. 



It is probable that we shall have to separate from the Squirrels certain 



