RODENTIA. 



521 



FlG. 447. SQUIRREL. 



The Flying Squirrels (Pteromys *) have on each side of the body 

 a prolongation of their . skin, extending between the fore and 

 hind legs, and forming a parachute, by the aid of which these 





FlG. 448. ROCKY MOUNTAIN FLYIXG SQUIRREL. 



* TrrepoV, pteron, a winq : avs, mus, a mouse or ratwinaed-rat. 



