GNAWING QUADRUPEDS. 227 



I. Sc. vulgaris. Common or Red Squirrel. 



II. MYOXUS. DORMOUSE. Perfect clavicles ; 

 grinders simple, four above, and four below on each 

 side, the summits flat ; tail long, covered with rather 

 long hairs directed laterally. 



1. M. avellanarius. Common Dormouse. 



III. Mus. MOUSE or RAT. Perfect clavicles ; 

 grinders simple, three above, and three below on 



:ach side, their summits tubercular ; upper incisors 

 ihisel-shaped, lower compressed and pointed ; tail 

 ong, tapering, annulated with scales, and nearly 

 mre. 



1. M. Eattus Black Rat. 



2. M. dccumanus. Brown Rat. 



3. M. domesticity. Common Mouse. 



4. M. sylvaticus. Field Mouse. 



5. M. messorius. Harvest Mouse. 



IV. ARVICOLA. VOLE. Perfect clavicles; grinders 

 imple, three above, and three below on each side, 



deeply grooved externally ; incisors very long ; 

 nuzzle obtuse ; toes separate ; tail shorter than the 

 body, round, annulated with scales, but hairy. 



1. A. amphibius. Water Vole. 



2. A. agrestis Field Vole. 



3. A. pratensis. Bank Vole. 



V. LEPUS. HARE or RABBIT. Clavicles incom- 

 3letc ; grinders simple, with flat summits, six above. 



