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THE SCIENCE OF LIFE. 



molars, sometimes very numerous, wanting, however, 

 enamel and roots. 



I IG. 164. Armadillo. 



Order 4. Rodent ia, (gnawers.) These have two long 

 curved incisors in each jaw, which serve for gnawing the 

 bark of trees, or other substances on which the Rodent 

 feeds. The front only is covered with enamel, and the 



rest of the tooth is 

 composed of softer 

 dentine, which, 

 wearing faster than 

 enamel, leaves a 

 chisel-like edge to 

 the tooth. Canine 

 teeth are wanting, 



FIG. i6 S .-skuii of Rodent. and the flat molars 



are separated from the incisors by a wide interval. (Fig. 

 165.) The hind legs of many Rodents, as the Hare and 

 Jerboa, are much longer and stronger than the fore-legs. 

 Most of the order are small in size, except the Capy- 



