HOOFED ANIMALS — Order, UNGULATA 
THIs is the great assemblage of animals whose toes are guarded 
by hoofs instead of armed with claws, and which feed on plants, 
—the herbivores. It embraces, besides many extinct groups 
and species, the cattle, sheep, antelopes, giraffes, deer, camels, 
swine, horses, rhinoceroses, tapirs, elephants, and their kindred. 
They exist in every part of the habitable globe except Aus- 
tralasia, have furnished sustenance to the larger Carnivora, 
and°have supplied the need of man for assistance in his labor, 
and with materials for food, shelter, and clothing. Without 
them human civilization would have been impossible. 
One cannot distinguish among the earliest mammals the 
forerunners of the carnivorous from those of the herbivorous 
lines; but before the end of the Eocene period Goudy: 
they become differentiated, and there appear forms ae 
clearly in the line of evolution toward the ungulate type. 
Thence onward they fall into distinct lines of development, 
termed suborders, the oldest and most generalized of which 
is the Condylarthra,”° which originated in the Cretaceous age 
and came to an end in the middle of the Eocene. These were 
animals of moderate size, imperfectly plantigrade, with five 
toes all around, teeth adapted both to cutting flesh and grinding 
plant tissues, and small, smooth brains. The best known is 
Phenacodus, —a slender, long-tailed creature, resembling a 
‘tapir in proportions, but smaller. The condylarths are believed 
to foreshadow the perissodactyls (see page 352); but their near- 
est representatives are a second suborder, the Hyracoidea, 
which, beginning in the earliest Eocene, has persisted until 
now in the African conies, rock-badgers, or hyraces. 
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