EIGHTH ANNUAL REPORT. 199 



its closest Eurasian relatives are farther removed than are those 

 of the other American genera of the Bovidae. In other words, 

 the gulf between Oreamnos and the nearest Eurasian form is of 

 generic instead of specific dimensions. 



In discussing the antiquity of Oreamnos, it must be borne in 

 mind that it may well be, and probably is, as recent an immigrant 

 as the other three genera of the Bovidae. A closely allied species 

 may have existed in Siberia until very recently. Once extinct, 

 and with no known fossil remains, we should have no trace of its 

 existence. In the case of the musk-ox, the Eurasian and Alaskan 

 forms died out, but their fossil remains were found and demon- 

 strated the former existence of the genus in those countries. 



As to the fossil record of the Bovidae in general, no sheep, 

 goats, antelope or true oxen have been found fossil in America. 

 In fact goats, antelopes, and true oxen never existed on this con- 

 tinent, and no bovines of any sort appear until the Middle Pleisto- 

 cene, so that all the American genera of the Bovidae are beyond 

 dispute of Eurasian origin. 



Comparing these four outlying groups with the wonderful de- 

 velopment which the members of this family attain in the Old 

 World, we cannot help regretting, either that the American rep- 

 resentatives have not been here longer, and evolved more dis- 

 tinct and striking types, or else that nature had, in the first in- 

 stance, been more lavish in the number of species which crossed 

 the Behring Sea land bridge. 



Considering the Family Bovidae as a whole, we find by far the 

 greatest number of genera and species in the Ethiopian region, 

 and there can be little doubt that further investigation of the 

 fossil fauna of Africa will disclose the ancestors of the extraor- 

 dinary bovine antelopes which flourish on that continent. 



It is most probable that all the Bovidae achieved their develop- 

 ment in Africa in Oligocene and Miocene times. They first ap- 

 peared in Eurasia, in the early Pliocene, became abundant and 

 spread rapidly throughout the continent, reaching North Amer- 

 ica at a much later period, the Middle Pleistocene. At an 

 early date some members of this family pushed to the far north, 

 and becoming adapted to boreal conditions, produced types like 

 the musk-ox. Others' accepted a mountain habitat, and developed 

 the goats, the sheep, and the mountain antelopes, the latter exem- 

 plified by the American Oreamnos. 



