304 MAMMALS 



Evidently the rabbit's sense of smell is well developed for 

 we often see it moving the end of the nose and upper lip 

 as though in the act of sniffing. 



Mouth and teeth. — The mouth is bounded by soft hps 

 and each jaw is furnished with teeth of two sorts, the in- 

 cisors and molars. There are two pairs of long, curved in- 

 cisors in the front of the mouth, one pair on the lower jaw 

 and one pair on the upper. These have sharp, chisel-like 

 edges which meet together and form a very efficient gnaw- 

 ing apparatus. Just behind the large pair of incisors on 

 the upper jaw is a second pair of small, scarcely noticeable 

 incisors. The front surfaces of the incisors are covered 

 with a very hard enamel, while the remaining portion of 

 these teeth are of a softer material. Thus it happens that 

 in gnawing the softer back portions are worn away leaving 

 a sharp cutting edge of enamel in front. Moreover, these 

 teeth grow as fast from their roots as they are worn off by 

 gnawing. This is also true of the teeth of rats, mice, 

 and other gnawers. The upper lip of the rabbit is split 

 in the middle so as to expose the incisors and facilitate the 

 work of gnawing. 



Back of the incisors there is a space on the jaws along 

 which no teeth are found. In a dog's mouth, the canine 

 teeth occupy some of this space. Finally, far back in the 

 rabbit's mouth are the molars, or grinding teeth, six pairs 

 above and five pairs below. The upper and lower molars 

 meet by flat, corrugated surfaces. The lower jaw has a 

 sliding, forward and backward m.ovement, while chewing, 

 thus grinding the food between the sliding surfaces of 

 the two opposing molars. 



The food. — The rabbit is a vegetarian pure and simple. 

 It hves upon clovers, grasses, buds and bark of trees, etc. 



