146 VERTEBRATA. MAMMALIA. 



Passing by several sub-genera, which we have 

 not space to notice, we come to the genus 



Mus,* the Mouse. 



This very numerous and widely extended group 

 of small, but troublesome and destructive, animals 

 is too well known to need much description. Their 

 grinders are tubercled, indicating an omnivorous 

 appetite, and their tails are usually naked and 

 scaly. The larger species are usually styled Rats, 

 and are very bold and intrusive. Some of the 

 species confine themselves to the habitations of 

 man ; such as the House Mouse (M. Musculus), 

 and the common Brown Rat (M. Decumanus), while 

 others, more timid, reside in the fields, and feed 

 on grain, roots, &c., as the Field Mouse (M. Sylvati- 

 cus), and the little Harvest Mouse (M. Messorius). 



There are some elegant and agile little Mice in 

 Africa, India, and North America, which have the 

 hind feet much .developed, and which elevate them- 

 selves, and leap in the manner of the Kangaroos. 

 In America they are called Deer-mice. They form 

 the genus Dipus^ the Jerboa. 



We can do no more than allude to the Hamsters 

 (Cricetus),^. and the Voles, or Water-rats (Arvicola), 

 through which we approach Castor, the Beaver. 



* Its Latin name. 



f Ava, duo, two, and oroyj, pous, a foot. 



% Kgigu (?) krizo, to cry out. 



Arvum, a field, and colo, to inhabit. 



