1 66 



THE GNAWERS OR RODENTS. 



body. The tail is round, thin, ringed, and 

 covered with inconspicuous scales. The thick 

 flat head is blunt in front, and carries small 

 ears; the short sturdy legs have five toes 



seldom on trees, and when attacked dart 

 courageously in large numbers on their assail- 

 ants. Allied genera (Ctenomys) advance as 

 far south as the desert tracts of Tierra del 



Fig. 226. The Degu (Octodon Cuminingii}. Vig. 227. The Larger Chinchilla (Kriomys 



connected by webs. The coypus live in pairs 

 in holes on the edge of the water; they are 

 excellent swimmers, but dive badly and sel- 

 dom ; they seek their food by day. 



THE DEGU FAMILY 



(OCTODONTIDA). 



This family owes its scientific name 1 to 

 the fact that the enamel folds of its four 

 cheek-teeth form on the grinding surface a 

 figure of 8. The feet have for the most part 

 five toes, and the collar-bone is always fully 

 developed. The typical species, the Degu of 

 the Chileans (Octodon Cummingii), fig. 226, 

 has the size, habit, and colour of a rat, and is 

 very abundant in Chile, where it does a great 

 deal of damage in cultivated fields and gar- 

 dens. These rats dig holes and galleries, 

 clamber about in hedges and shrubberies, but 



1 ! rom Gr. okto, eight, and odoits, odontos, a tooth. 



Fuego, and climb to the higher parts of the 

 Cordilleras. 



THE CHINCHILLA FAMILY 



(CHINCHILLIDA). 



South America, which is so rich in rodents 

 generally, possesses another family of impor- 

 tance for us, that of the Chinchillida. The 

 distinguishing character of this family is 

 formed by the four rootless cheek-teeth, 

 which consist of two or at the most three 

 bands of enamel placed obliquely and con- 

 nected together in such a manner that each 

 tooth appears to be composed of two oval 

 halves. The collar-bones are complete; the 

 fine soft fur is almost woolly. 



The Chinchillas Proper (Eriomys or Chin- 

 chilla) occupy the first place in this family. 

 They lead a similar life to our marmots, and 

 are natives of the higher rocky and treeless 



