MAMMALIA 



129 



pattern, suggesting a double series of opposed triangles alternating 

 with one another. The largest of our three species is the Water- 

 Vole [Microtus amphibius), often miscalled the Water "Rat". It 

 is brown in colour and about the same size as an ordinary brown 

 rat (fig. 88). The Bank -Vole {M. glareolus) is less stoutly- 

 built, with redder fur and longer tail. Much smaller and more 

 abundant than 



these two species 

 is the Field -Vole 

 {M. agrestis),^\i\<:^ 

 sometimes multi- 

 plies to such an 

 extent as to become 

 a serious agricul- 

 tural pest. It is 

 often called the 

 Short-tailed Field- 

 Mouse, but is at 

 once distinguished 

 from a mouse by 

 its shorter tail, and 

 by the other fea- 

 tures already enu- 

 merated as char- 

 acteristic of voles 

 generally. 



Other examples 

 of the Mouse family 

 are afforded by the 

 Hamsters, Lem- 

 mings, and Musquashes. The Common Hamster {Cricetus fru- 

 mentarius) of Europe and North Asia is a comparatively large 

 rodent, being as much as a foot in length inclusive of the short 

 tail, the abbreviated nature of which at once shows that the crea- 

 ture is not a rat, which animal it otherwise somewhat resembles 

 in external appearance. There are very large cheek-pouches. 

 Hamsters are burrowing forms, and they store up large quantities 

 of grain, seed, and other vegetable matter. They increase very 

 rapidly in number and often do serious damage to crops. The 

 White -footed Mouse (C. leucopus) of North America is closely 



Vol. I. 9 



Fig. 89. — The Lemming {Myodes lejnmus) 



