402 INTRODUCTION TO ZOOLOGY. 



upon the back of the parent." Such is the case in the 

 species represented in the annexed figure (Fig. 303). It 



might puzzle us to 

 imagine by what means 

 | the young could retain 

 their places, while the 

 mother was rapidly 

 , changing her position 

 among the branches of 

 a tree. But the young 

 Opossums adopt a 

 Fig. SOSOPOSSUM.* ready mode of guarding 



against the danger of a fall, by entwining their long tails 

 round the tail of their mother. 



ORDER RODENTIA.f RODENTS OR GNAWING 

 ANIMALS. 



THE preceding order was composed exclusively of animals 

 belonging to foreign countries. The present is well represented 

 among our native quadrupeds, as the British species amount 

 to fourteen in number, and are illustrative of some of the 

 most important families. The characteristics of the group are 

 so well developed in the Rat and the Mouse, that the family 

 to which they belong is regarded as typical of the order. 



In the precise language of Mr. Jenyns the order is thus 

 defined: " Incisors two in each jaw, large and strong, 

 remote from the grinders; tusks none; toes distinct with 

 small conical claws. "J The total number of species is six 

 hundred and four, being two-fifths or nearly one-half of the 

 entire number of mammalia known at the present time. 



* Fig. 303. The Marmose of M. Edwards' Elemens. The Murine 

 Opossum (DidelpMs mvrina), of Waterhouse and others. 



| From the Latin rodcre, to gnaw; rodens, gnawing. The term glires 

 is also applied to the present order, from the Latin glis, gliris, a Dormouse. 



J Manual of British Vertebrate Animals. 



G. R. Waterhouse, Esq. in Berghaiis and Johnston's Physical Atlas. 



