THE BRITISH MAMMALS PAST AND PRESENT. QI 



Spermophilus erythrogenoides (Pleistocene and 

 Caves). 



CASTORIDM. 



Castor fiber (Forest Bed, Pleistocene, Caves, and 

 Existent in northern hemisphere. Extinct in British 

 area since 1188, but re-introduced under preserva- 

 tion), Beaver. 



Castor veterior (Red Crag). 



Trogontherium cuvieri (Norwich Crag and Forest 

 Bed). 



Trogontherium minus (Red Crag). 



MYOXID&. 



36. Muscardinus avellanarius (Existent), Dormouse. 



MURIDJE. 



37. Mus minutus (Existent), Harvest Mouse. 

 Mus lewisi (Pleistocene). 



38. Mus sylvaticus (Forest Bed and Existent), Wood 



Mouse. 



39. Mus sylvaticus wintoni (Existent), Yellow-necked 



Mouse. 



40. Mus musculus (Pleistocene, Caves, and Existent), 



Common Mouse, 



41. Mus rattus (Existent), Black Rat. 



42. Mus decumanus (Caves and Existent), Brown Rat. 



43. Microtus agrestis (Pleistocene, Caves, and Existent), 



Field Vole. 



44. Microtus amphibius (Pleistocene, Caves, and Exist- 



ent), Water Vole. 



Microtus arvalis (Forest Bed, Caves, and Existent 

 in Europe), Continental Field Vole. 



45. Microtus glareolus (Forest Bed, Caves, and Exist- 



ent), Bank Vole. 

 Microtus gregalis (Forest Bed, Caves, and Existent 



in Northern Asia), Siberian Vole. 

 Microtus intermedius (Norwich Crag and Forest 



Bed). 

 Microtus nivalis (Prehistoric, and Existent in Alps 



and Pyrenees), Alpine Vole. 

 Microtus ratticeps (Pleistocene, Caves, and Existent 



in Northern Europe), Northern Vole. 

 Cricetus songarus (Caves). 



