1304 



THE RODENTS 



varying from four to eight, while as many as six different litters may be produced 

 in a single season. Moreover, it is probable that the young produced in the spring 

 will themselves be parents in the following autumn. On the Continent the plagues 

 of voles are even more serious than in England. Thus, according to Brehm, during 

 a visitation of these animals which took place in Germany in the year 1822, up- 

 ward of 1,570,000 were taken in one district, 590,327 in another, and 271,941 in a 

 third. Again, in the summer of 1861, a total of 409,523 voles were taken in a 

 single district of Rhine- Hessen. 



The third species of the genus in Britain is the bank vole ( M. glare- 



olus) , which may be distinguished externally from the field vole by 



the color of the back inclining more or less markedly to rufous, and also by its 





THE ALPINE VOLE. 

 (Two-thirds natural size.) 



larger ears, and proportionately- longer tail, which is equal to half the length of the 

 head and body, The molar teeth differ from those of the field vole not only by the 

 circumstance that in the second one of the upper jaw there are but four prisms, but 

 also in that in the adult state these teeth form imperfect roots. The whole propor- 

 tions of the bank vole are more elegant than those of the field vole, while the fur is 

 more smooth and glossy, the coloration more brilliant, and the eye larger. It is 

 found locally over England and parts of Scotland, as far north as Morayshire, while 

 abroad it ranges from France across Asia to China. Its general habits are the same 

 as those of the field vole, but it' is said to be more generally found in sheltered situ- 

 ations, and is especially fond of visiting gardens. 



There is, however, a great probability that both the bank vole and the red- 

 backed vole (M. gapperi} of North America, are merely local varieties of the Arctic 



