MUS. RAT. 



43 



Generic Character. 



Denies Primores superiores 



cuiieati. 

 Molar es utrinque tres, ra- 



rius duo. 

 ClavicuU perfect3e. 



Upper Front - teeth wedge- 

 shaped. 



Grinders on each side three, 

 sometimes only tv/o. 



Clavicles^ or collar-bones in 

 the skeleton. 



1 HIS numerous tribe constitutes a formidable 

 phalanx against which mankind finds it necessary 

 to employ the various artifices of extirpation^ in 

 order to lessen the ravages occasionally suffered 

 by its depredations. In our own island the black 

 and the brown rats, the field and domestic mice 

 are the principal destroyers ; but in otlier parts 

 of Europe, as well as in the hotter regions of 

 Asia, Africa, and America, many other species 

 still more noxious and formidable are found. 

 The different kinds vary considerably in their 

 manner of life, some confining themselves en- 

 tirely to vegetable food, ^vhile others are poly- 

 phagous, destroying with indiscriminate avidity 

 almost any animal or vegetable substance to 

 which they can gain access. Their pace is, in 

 general, rather quick, and their most usual resid- 

 ence is in obscure subterraneous retreats, from 



