38 ANIMAL COMPETITORS 



ears, half an inch long, very small eyes, and- 

 long naked tail, are unlike those of any native 

 mouse. Its total length is about 7 inches, 3^> 

 of which belong to the tail. Its molar teeth 

 have each three tubercles, instead of two, as 

 in our own wood-mice; and its incisors are un- 

 grooved, by which, at any rate with the aid of 

 a magnifying glass, the marks of its biting are 

 readily identified. 



Its gray protective coat has seemed satis- 

 factory under all circumstances, for there is no 

 perceptible difference between representatives 

 of the species in the four quarters of the globe. 

 In general the type seems singularly invariable, 

 only one or two varieties having arisen, such as 

 the queer rhinoceros mice which appeared in 

 England some years ago, and took their name 

 from their hairless, deeply-folded skin which 

 gave them the appearance of miniature rhinos. 

 This fixity of type may be due in part to the 

 fact that every country has received a con- 

 stant immigration of fresh blood by means of 

 ships and other conveyances. 



Japanese dancing-mice. One strange vari- 

 ety, however, has arisen, probably in China 



