438 MAMMALIA. 



but these form exceptions. The Rodents, therefore, like all 

 herbivorous animals, have the intestinal canal of great length. In 

 the Guinea-pig it measures nearly 10 feet ; in the domestic Eabbit, 

 15 feet 2 inches ; in the Agouti, 17 feet 10 inches ; in the Porcu- 

 pine, 25 feet. Eodents diifer much in form and size, and their 

 organs of locomotion are as variously constituted. They are 

 adapted, according to the genus, either for running, jumping, 

 climbing, flying, or swimming. Their toes are generally five in 

 number, and touch the ground with the extremities only— a cir- 

 cumstance which is favourable to agility. They are armed with 

 sharp claws, enabling them to climb trees or to burrow in the 

 earth. 



The srreater number of Rodents have their bodies covered with 

 fine, soft, and sometimes prettilj'-colourcd hair, which man has 

 turned to advantage. The small Grey Squirrel and the Chinchilla 

 both furnish furs of value ; and the coats of the Beaver, the Hare, 

 and the Eabbit, are used in several of our manufactures. 



The Rodents do not, like the other Orders of Mammals, admit 

 of anj' great divisions, based on natural characteristics which 

 are readily and clearly marlved. When such have been adojDted 

 by naturalists, they have been founded on nothing but certain 

 subtle features of organisation. We shall not, therefore, in this 

 case, classify them in families ; but confine ourselves to describing 

 the genera one after the other, grouping under a common head 

 those which are connected together by certain actual affinities. 



The order of Eodents commences with a very numerous group, 

 that of the Eat genus, which includes, besides the Rat proper, the 

 Field Eats and Mice, the Ondatras, Musquash, or Musk Eats, the 

 Hamster Eats, the Dormice, and the Jerboa Eats. All these 

 animals have a kind of family likeness to one another, and diifer 

 but little in the eyes of the vulgar, who mix them all up under 

 the same general denominations. These form the Mus species of 

 the naturalists (from Mas, Mouse or Eat). 



Rids. — Rats proper are characterised hj an oblong-shaped 

 head, furnished with stiff feelers on each side of the muzzle ; bj' an 

 elongated body terminated by a tail equal to it in length, and almost 

 bare, scalj-, cylindrical, and tapering down to the tip. They have 

 but four toes on the fore feet, and the number of their teats varies 

 from four to twelve. They are usually of a tawnj- or brown colour. 



