78 ORDERS OP THE CLASS MAMMALIA." 



closely connected with these characters, besides a 

 variety of other comparative differences, not merely 

 physical, but even intellectual. 



The degree of perfection of the organs of touch 

 may be estimated according to the number and mo- 

 veableness of the fingers, and according to the 

 greater or less proportion of depth in which their 

 extremity is enclosed in the claw or hoof. 



A hoof which completely envelopes that part of the 

 extremity which would otherwise touch the ground, 

 blunts the power of tact, and renders such extre- 

 mity incapable of seizing any thing. 



The opposite extreme to this is when a nail forms 

 a single lamina on one side of the end of the finger 

 or toe only, leaving to the other all its sensibility. 



The nature of the diet may be judged of by the 

 cheek teeth, to the form of which the articulation of 

 the jaws invariably corresponds. 



For cutting flesh the cheek teeth are trenchant 

 like a saw, and the jaws are fitted together so as to 

 move in the manner of a pair of scissors, and are 

 incapable of any other motion than that of simply 

 opening and closing again in a vertical direction. 

 The cheek teeth adapted for the mastication of grains 

 or roots, have a flattish round upper surface, or rather 

 the shape of a flat coronet, and the jaws possess the 

 capacity of horizontal motion. That the surface of 

 such cheek teeth should keep that sort of inequality 

 peculiar to a millstone, their substance is composed 

 of parts of unequal hardness, some of which parts 

 wear sooner than others. 



