RODENTIA. 79 



they had been crushed. They are without a tail; have five nails on each of 

 the fore feet, and four, with a small tubercle, in place of a thumb, on each of 

 the hind ones, all very long and fit for digging. Their gait is excessively 

 slow. They have two long incisors in each jaw, almost similar to those of the 

 Rodentia ; and each of their grinders has two transverse ridges. 



They feed on grass. One species only is known, the 



Phas. ursinus. (The Wombat.) Size of a badger; fur abundant, of a 

 more or less yellowish brown. It is found in King's Island, to the south of 

 New Holland, where it lives in its burrow. Its flesh is excellent. 



ORDER V. 



RODENTIA. 



WE have just seen, in the Phalangers, canini so very small that we cannot 

 consider them as such. The nutriment of these animals, accordingly, is 

 chiefly derived from the vegetable kingdom. Their intestines are long; and 

 the Kanguroos, which have no canini whatever, subsist upon vegetables only. 

 The Phascolomys might stand first in that series of animals of which we are 

 about to speak, and which have a system of mastication still less complete. 



Two large incisors in each jaw, separated from the molars by an empty 

 space, cannot seize h'ving prey nor tear flesh ; they cannot even cut the food, 

 but they serve to file, and by continued labour to reduce, it into separate par- 

 ticlesin a word, to gnaio it ; hence the term Rodentia or Gnawers, which is 

 applied to animals of this order. It is thus that they successfully attack the 

 hardest substances, frequently feeding on wood and the bark of trees. The 

 more easily to accomplish this object, the incisors have no thick enamel, except 

 in front ; so that their posterior edges wearing away faster than the anterior, 

 they are always naturally sloped. Their prismatic form causes them to grow 

 from the root as fast as they wear away at the edge ; and this tendency to 

 increase in length is so powerful, that if one of them be lost or broken, its 

 antagonist in the other jaw having nothing to oppose or comminute, becomes 

 developed to a most monstrous extent. The lower jaw is articulated by a 

 longitudinal condyle, in such a way as to allow of no horizontal motion, except 

 from back to front, and vice versa, as is requisite for the action of gnawing. 

 The molars also have flat crowns, whose enamelled eminences are always 

 transverse, so as to be in opposition to the horizontal motion of the jaw, and to 

 increase the power of trituration. 



The genera in which these eminences are simple lines, and the crown is very 

 flat, are more exclusively frugivorous ; those in which the eminences of the 

 teeth are divided into blunt tubercles are omnivorous ; while the small number 

 of such as have no points more readily attack other animals, and approximate 

 somewhat to the Carnaria. 



The form of the body in the Roclentia is generally such, that the hinder 



