EIGHTH ANNUAL REPORT. 
19 
THE UNGULATES. 
The next great group to be considered is the order of Ungu- 
lates. 
PECCARIES. 
Like the American deer and prong-horn, the peccaries form a 
peculiar American family, Dicotylidae, and are the American 
equivalents of the Old World swine, to which they are not closely 
related. They entered South America in the Pleistocene, but 
existed in North America throughout the Pliocene, Miocene and 
back into the Oligocene, and their North American ancestry has 
been clearly traced. 
BOVINES. 
BISON. 
The next family of the Ungulates is the Bovidae, and its larg- 
est American member is the bison, Bison americanus, which is very 
closely related to the European bison or wisent, B. bonassus, now 
often mis-called the aurochs. 
The American bison is probably a relatively recent immigrant 
from the Old World. It does not occur in the Lower Pleistocene 
Equus fauna, but comes in abundantly just above. Several other 
species of fossil bison go back to about the Middle Pleistocene, 
one, B. prisons, being found fossil both in Europe and in Alaska. 
These bison probably represent other species which arrived at the 
same time, rather than the ancestral stock of the living animal. 
Additional proof of its recent arrival is indicated by the fact 
that while attaining the greatest numerical development of any 
American hoofed animal, and with an immense range, extending 
from Great Slave Lake to Mexico, from the Rockies to the 
Atlantic tidewater, and northeastward into New York State, it 
appears to have developed but one imperfectly marked subspe- 
cies in the far North, known as the wood buffalo, B. americanus 
athabascae. 
MUSK-OX. 
The bovine nearest to the bison, in point of size, is the musk- 
ox, Ovibos moschatus, which is now entirely confined to the Bar- 
