108 T.HE VITAL FUNCTIONS. 



matic arch. The lateral motions of the jaw are effected by 

 muscles placed internally between the sides of the jaw and 

 the basis of the skull. 



In the conformation of the teeth and jaws, a remarkable 

 contrast is presented between carnivorous and herbivorous 

 animals. In the former, of which the Tiger , Fig. 274, may 



be taken as an example, the whole apparatus for mastication 

 is calculated for the destruction of life, and for tearing and 

 dividing the fleshy fibres. The molar teeth are armed with 

 pointed eminences, which correspond in the opposite jaws 

 so as exactly to lock into one another, like wheel-work, when 

 the mouth is closed. All the muscles which close the jaw 

 are of enormous size and strength, and they imprint the 

 bones of the skull with deep hollows, in which we trace 

 marks of the most powerful action. The temporal muscles 

 occupy the whole of the sides of the skull (T, T;) and by the 

 continuance of their vigorous exertions, during the growth 

 of the animal, alter so considerably the form of the bones, 

 that the skulls of the young and the old animals are often 

 with difficulty recognised as belonging to the same species.* 

 The process of the lower jaw (seen between T and T,) to 

 which this temporal muscle is attached, is large and promi- 

 nent j and the arch bone (z,) from which the masseter arises, 

 takes a wide span outwards, so as to give great strength to 



* This is remarkably the case with the Sear, the skull of which exhibits, 

 in old animals, a large vertical crest, not met with at an early period of life. 



