ORDER RODENTIA. 63 



rather than walk. In some sub-genera, this confor- 

 mation is even as disproportionate as in the Kanga- 

 roos. 



The intestines of the Rodentia are very long, 

 their stomach is simple, or very little divided, and 

 the caecum is often extremely voluminous, even 

 more so than the stomach; nevertheless, the sub- 

 genus Myoxus is without this intestine. 



In this entire order, the brain is almost entirely 

 smooth, and without circumvolutions. The orbits 

 are not separated from the fosses temporales, which 

 have not much depth. The eyes are altogether di- 

 rected laterally ; the zygomatic arches being slight 

 and curved below, indicate the weakness of the 

 jaws. The fore-arms are scarcely capable of turn- 

 ing, and their two bones are frequently united. In 

 a word, the inferiority of these animals is manifest 

 in most of the details of their organization. 



However, the more numerous genera which pos- 

 sess stronger clavicles, have a considerable degree 

 of dexterity, and make use of their fore-feet to carry 

 their aliments to the mouth. Of them we shall 

 form our first division. 



The most remarkable genus of this division is 

 that of 



The Castors (Castor, L.), 



Which are distinguished from all the other Ro- 

 dentia by their tail, which is horizontally flattened, 



of a form nearly oval, and covered with scales. 



G 2 



