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 Cuinmitigii)* 



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 From Gr. okto, eight, and odous, odontos, a tooth. 



Fig. 227. — The Larger Chinchilla (Eriomys chinchilla). 



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 



