118 RODENTIA. 



by its habit of burrowing in the ground. The ground- 

 colour of the upper parts of the body is tawny brown ; 

 along the back are five longitudinal black bands ; the space 

 between that on the dorsal line, and the first band on each 

 side, is light yellow, that which divides this band from the 

 outer one being dirty white ; on the head there are four 

 streaks, two of them whitish, the others rusty brown ; the 

 tail is blackish above, until near the tip, where it becomes 

 quite black, the tip itself being white. 



Body, 5£ inches ; head, 1% inch ; tail, 4 inches. — F. M. 



The Ground Squirrel makes its burrow with an entrance 

 at each end, and with several side chambers, where it lays 

 up its winter stores of various sorts of grain. 



It is found all through Siberia, and extends into that 

 corner of Europe which lies between the rivers Kama and 

 Dwina and the Ural Mountains. 



A species, said to differ from the above only in some of 

 its markings, inhabits a great part of North America. 



Genus PTEROMYS. 



Teeth. — Incisors, -| ; molars in the young, ~^ ; in the 

 adult, j^j ; the anterior molar in each upper jaw falls 

 out when the animal becomes old ; ears rounded ; eyes 

 large ; fore-feet with four long toes, armed with sharp 

 claws ; thumb rudimentary, with a blunt claw ; hind-feet 

 formed for climbing, with four widely divided toes. The 

 skin of the sides is very much extended between the fore- 

 and hind-legs, so as to sustain the animal in the air when 

 taking its long leaps. The feet are provided with a bony 

 appendage, intended to support this membranous extension ; 

 tail long, velvety, sometimes with distichous hairs. 



