THE GRAY SQUIRREL 



399 



ornament ; it is useful as a balancing organ in the long leaps 

 from branch to branch ; and it serves to keep the squirrel 

 warm in its nest in cold weather. 



The Digestive System. The mouth is provided with fleshy 

 lips, which assist in seizing and holding food. On the ventral 



FIG. 210. Photograph of Gray Squirrel 



surface of the mouth rests a large, fleshy tongue (Fig. 213, 5), 

 with numerous nerve-endings of the organ of taste (papillae) 

 scattered over the surface. Two kinds of teeth are present. 

 The front teeth, called incisors (Fig. 213, 4), are long, sharp, 

 and chisel-shaped, and are fitted for gnawing; those in the 

 back of the jaw, separated from the incisors by quite a space, 



