EIGHTH ANNUAL REPORT. 25 



Rockies ; and, third, the Columbia black-tailed deer of the Pacific 

 coast, O. columbianus, with its outlying subspecies in the North, 

 the Sitka deer, O. c. sitkensis. 



The genus Odocoileus departs widely from all the Old World 

 types. Its closest allies, as far as foot structure is concerned, are 

 A Ices and Rangifer. 



These American deer have been on this continent for a very 

 long time, possibly as far back as the Miocene. They have spread 

 throughout both North and South America, and have developed 

 many well-defined species, both facts indicating a long period of 

 radiation on this continent. The antlers of Odocoileus cannot be 

 in any way correlated with those of any other genus of the deer 

 family, least of all with those of Cervus. 



All the members of the Cervidae sprang originally from the 

 same stock, but this ancestral form was either hornless, or else 

 had a simple spike, with, at most, a single branch, resembling the 

 dag-antler of the yearling. This spike-horn ancestor is probably 

 the correct explanation, as otherwise it is necessary to assume 

 that the different members of the deer family acquired the ex- 

 traordinary character of deciduous antlers independently, and to 

 find a common ancestor we should have to go back to a hornless 

 cervine, resembling the existing musk-deer or the Chinese water 

 deer. 



A Miocene group of ruminants found in North America, 

 which has heretofore been considered as possibly ancestral both 

 to Odocoileus and Antilocapra, proves, on close investigation, to 

 be a new and separate family, or at least a clearly defined subfam- 

 ily of the Bovidae. This group includes Cosoryx, Blastomeryx 

 and Merycodus. 



These merycodonts are practically antlered antelopes, being in 

 foot structure, the high molar crowns, and in other char- 

 acters, close to the bovine antelopes, and still closer to Antilo- 

 capra, and, were it not for the antlers, they might be considered 

 ancestral to the latter. In this affinity to the prong-horns they 

 suggest an American ancestry for that animal. 



Paleomeryx, however, is a true deer, and is found both in the 

 American Miocene and in the European Oligocene. It is a gen- 

 eralized cervine. The American forms had unbranched antlers, 

 situated directly over the eye, apparently with permanent velvet, 

 and without a burr, suggesting in these respects the giraffe. The 

 European forms, however, although earlier, were much more spe- 

 cialized, and had both a burr and naked antlers, with a single 

 prong. 



