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, Paleotherium, 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 (?. ¢., 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 Coryphodon, 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 vertebra, and a simple: 
stomach, with a large, sacculated cecum. The tapirs are 
the more elemental, generalized forms. Fossil tapirs occur: 
in the older Tertiary beds of the West. The snout is 
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 
