THE LIFE OF MAMMALS 
head with short, ovate ears, and on the male an apology for ant- 
lers in the shape of two tiny spikes rising from the forchead. 
This concludes the Ruminantia termed ‘‘Pecora”’ (oxen, 
sheep, goats, antelopes, giraffes, and deer), which agree in hav- 
ing horns, two functional toes (only), and the metapodials 
fused into a cannon bone. There remain two other small divi- 
sions of ruminants, — the camels and the chevrotains. 
¢ 
The camels and llamas (or “ yahmas”’) form a group (Tylo- 
poda) very much older than the ruminants, and of American 
Ancestry of OFigin. That the camel got the pads on his feet, the 
Camels water-pockets in his stomach, and other drought and 
sand resisting arrangements from an ancestry that began in the 
western United States a million years or so ago, is the novel and 
interesting outcome of discoveries by Cope, developed still further 
by Dr. Wortman and his assistants of the American Museum in 
New York.*° These scientific explorers brought to light a series 
of skeletons showing that the camel race, now confined to the 
desert regions of Africa and Asia, originated in North America, 
and was developed there along a line of adaptative growth. 
It must be remembered that in the early Tertiary there was a slow but 
persistent upheaval of the Rocky Mountain region, where a vast plateau, 
studded with lofty sierras, gradually freed itself from the sea. In those 
sierras were many active volcanoes, whose outpourings of volcanic dust 
settled and solidified into rock, forming the whole thickness of many well- 
known fossiliferous formations. The basins between the mountain ranges 
contained vast quiet lakes, of which Great Salt Lake is a relic, into which 
dead animals would drift and their bones become fossilized; and also desert 
spaces, constantly extending, where winds blew the light soil about, and 
gradually buried dead animals and perhaps frequently smothered and 
entombed many of those whose skeletons show so astonishingly little sign 
of disturbance. In the very oldest of these rocks, at the dawn of the Eocene, 
have been found what some geologists consider the primitive ancestors of 
the camel, — small creatures, little known; but the upper Eocene beds 
yield skeletons of whose affinity to ordinary camels there can be no doubt. 
These belong to an animal named Prototylopus, which was hardly larger 
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