ORDER OF UNGULATES. 601 



type is the horse, with its single toe on each limb. A large 

 number of extinct Tertiary Ungulates in the Western States 

 and Territories, and the Tertiary basins of Paris and Lon- 

 don, more or less allied to the tapir, especially Coryphodon, 

 Anoplotherium, Palceotherhim, etc., were generalized or 

 ancestral forms, from which the modern, more specialized 

 types have probably been evolved, and a study of these fossil 

 Ungulates shows that there was then (i. e., in Eocene times) 

 an essential unity of organization in all Ungulates, including 

 the Ruminants ; the breaking up of the Ungulate stem into- 

 special groups, along favored lines or paths of development,, 

 having resulted in a gradual improvement and elabora- 

 tion of particular parts, which rendered them more fitted 

 for their present life, and more intelligent in meeting and 

 overcoming the emergencies their more complex surround- 

 ings subjected them to. Thus in the Eocene Ungulates, 

 such as Corypliodon, the cerebrum was small, without convo- 

 lutions, indicating a slight degree of intelligence compared 

 with the modern Ungulates, while the gradual differentiation 

 of the horse, with its single toe and hoof, from its tapir-like- 

 ancestors, is a marked example of the intelligent, beneficent 

 selection of favored, useful types which has gone on from the 

 earliest geological times. 



All this specialization of type involved the destruction of 

 great numbers of forms unfitted to withstand changes in 

 their surroundings, or not sufficiently intelligent or wary to 

 avoid the attacks of carnivorous forms, and thus the present 

 number of Ungulates is much exceeded by the fossil forms. 



Perissodactyles. The odd-toed Ungulates, on the whole,, 

 stand lower than the even-toed forms. They all have at 

 least twenty-two dorsal and lumbar vertebrae, and a simple- 

 stomach, with a large, sacculated coecum. The tapirs are- 

 the more elemental, generalized forms. Fossil tapirs occur 

 in the older Tertiary beds of the West. The snout ia 

 almost proboscis-like, and the legs are moderately long, with 

 four toes in front, three toes behind. The tapirs inhabit the 

 tropics of the New World and Sumatra. They are succeeded 

 by the rhinoceros, represented in this country by a number 

 of extinct Tertiary allies, the living species being restricted 



