UNGULATED AND UNGUICULATED MAMMALIA. 131 



round by the movement of one of these bones on the other (ANIM. 

 PHYSIOL. 639). In this order, the mouth is remarkably adapted 

 for grinding down hard vegetable substances ; the molar teeth 

 being furnished with transverse ridges of enamel, and the jaws 

 having a powerful movement forwards and backwards. In 

 others, again, there is an almost exclusive adaptation to animal 

 food; and in these we find the unguiculated structure in the 

 highest perfection, the claws being sharp and long, and the hand 

 or fore-foot being capable of being placed in a great variety of 

 positions, by the rotation of the two bones of the leg. The 

 grinding teeth are very narrow, and are raised into sharp points 

 and edges, so as to be adapted for dividing animal flesh ; and 

 these are firmly set in short strong jaws, which are fitted 

 together like the blades of a pair of scissars, having no action 

 but a vertical one. In this group, too, we find the greatest 

 development of the canine teeth ; which are commonly absent, 

 or but slightly developed, among herbivorous quadrupeds. These 

 are the most powerful weapons with which carnivorous animals 

 are furnished ; serving both for the first attack of their prey, 

 and for subsequently tearing it in pieces. To this division, also, 

 belongs the Bat tribe, in which the extremities are provided 

 with distinct claws, and the teeth adapted (for the most part, at 

 least) to an animal diet ; and to it we are also to refer a portion 

 of the Fish-like Mammals, in which the structure of the teeth 

 and digestive apparatus is closely allied to that of the Carnivora, 

 as is the case in the ordinary "Whales and their allies ; whilst 

 another portion, consisting of but a few species, is to be referred 

 to the herbivorous division, on account of a similar conformity 

 in general structure. 



120. Among the Unguiculated Mammalia, there are some 

 which have the power of opposing one of the fingers to the rest ; 

 and this, either on the two anterior extremities alone, or on the 

 posterior also. This is a character, which is so closely connected 

 with the general conformation and habits of the animals that 

 possess it, as to be of the highest importance in classification ; 

 and accordingly it serves to distinguish the two first orders of 

 the Unguiculated from all the rest. These orders are : 



K 2 



