108 ORIGIN OF LIFE IN AMERICA 



and it differs in other fundamental characters from the mule 

 deer, which has apparently no near relations in the Old World, 

 and which we may justly call the true American deer. 



Fossil remains of the mule-deer have been found in the 

 Conard Fissure.* The fossil bones of other deer from the 

 Pleistocene of Illinois, Iowa, Wisconsin and Indiana, have 

 been referred to extinct species of the genus Odoeoileus to 

 which the mule-deer belongs. No Pliocene or older traces 

 of this genus have as yet been discovered in North America, 

 if we adopt the generally accepted view of the Conard Fissure 

 being of Pleistocene age. Altogether there are three fairly 

 distinct species of the type of the mule-deer in North America, 

 namely the one I have just described, the white-tailed deer 

 (Odocoileus virginianus) and the black-tailed Columbian deer 

 (0. columbianus). 



It is of considerable interest to know that this genus lives 

 not only in Central America, but right to the southern ex 1 - 

 tremity of South America in Chile. This fact alone is remark- 

 able, for nowhere else in the world are deer found south of the 

 Equator. They are entirely absent from Africa and Australia. 

 However, it is by no means the only noteworthy circumstance 

 about this American group of deer. Those who are ac- 

 quainted with the habits and life history of the deer tribe 

 know that the young of deer with large branching antlers, 

 at first possess no antlers. Afterwards small, simple and 

 unbranched processes appear on their heads. From year 

 to year they are shed and new ones take their place, and these 

 are always a little more complex than the previous ones. The 

 gradual development of the race seems to follow that of the 

 individual. It is only in the more recent geological periods 

 that deer with branching antlers make their appearance. As 

 we go back to earlier deposits the deer skulls only bear simple 

 antlers with one or two branches. In still older strata we 

 meet with deer that were devoid of antlers, while they gene- 

 rally possessed long canine teeth which no doubt were useful 

 as organs of defence. It has been rightly argued that the 

 complex antlers have only been developed in comparatively 

 recent geological times, and that deer with simple antlers 



* Brown, Barnum, " Conard Fissure," p. 205. 



