76 



dog, is nothing more than a long elastic ligament 

 under the tongue, corresponding to the lingual 

 cartilage of some of the inferior classes. 



The most remarkable feature in the lower jaw 

 of quadrupeds is, the different character of the 

 moveable joint in the herbivorous and carnivo- 

 rous ; in the former of which it is calculated to 

 admit of motion chiefly from side to side, and in 

 the latter, chiefly upwards and downwards ; of 

 the muscles which move it also, those which act 

 in the lateral direction are strongest in the her- 

 biverous quadrupeds, while those which act 

 in the perpendicular direction are strongest in 

 the carnivorous. If we observe the motions of 

 the lower jaw, respectively in a sheep and in a 

 dog, while engaged in chewing their food, we 

 shall at once perceive these differences ; and 

 a knowledge of the anatomy of each directly 

 displays to us how admirably the structure of 

 the several parts is adapted to produce, on the 

 one hand the grinding, and on the other, the 

 crunching motion, which a herbivorous arid 

 carnivorous animal respectively requires. The 

 general form of the lower jaw, likewise, dif- 

 fers very materially in the two ; being much 

 more elongated generally in the former than in 

 the latter, to admit of the insertion of the nu- 

 merous broad flat teeth which this grinding pro- 

 cess demands. If the lower jaw of herbivorous 

 and carnivorous quadrupeds differ so much from 

 each other, the differences in the teeth of each 

 are still more remarkable, arid still more iridica- 



