6 ORIGIN OP LIFE IN AMEEICA 



ten species now reaognised in America will be reduced to 

 four well-marked species. 



How long the caribou or reindeer has been in existence 

 we do not know. Its remains have been discovered both in 

 Europe and America in deposits believed to have been laid 

 down during the Pleistocene Period, and as these occur far 

 to the south of its present range, it has invariably been 

 assumed that the species w,as compelled, owing "to unfavour- 

 able climatic changes to abandon its more northerly habitat. 

 When the climate became once more suitable to its require- 

 ments, the reindeer is supposed to have returned' to its, original 

 home. This idea suggests that the reindeer originated in 

 pre-Glacial times, and this view is, in my opiniom, supported 

 by the evidence of its occurrence, conjointly with the hyaena, 

 in Irish cave deposits.* 



The whole subject of the influence of the Glacial Epoch 

 on animals and plants will be dealt with later on, and need 

 not be considered here. The fact of the occurrence of un- 

 doubted reindeer remains far to the south of its present 

 range certainly requires an explanation, and this is more 

 easily given in conjunction with other facts to be stated 

 in this chapter. While .the reindeer still lives in Europe no 

 (further south than the fifty-second degree of latitude, in 

 America it is found no less than seven degrees further south. 

 In former times it inhabited Oregon and Kentucky. In the 

 east it came down to the neighbourhood of the present site 

 of New York City, whereas in Europe it advanced as far as 

 Mentone on the shores of the Mediterranean, and penetrated 

 to the north of Spain, i.e., to the latitudes of the thirty-eighth 

 degree in America and of the forty-tliird degree in Europe.f 



The musk ox (Ovibos moschatus) is another even more 

 arctic mammal than the reindeer. So called from the musky 

 odour of its flesh, this species was believed to be more closely 

 allied to the sheep than to the ox, which it resembles more in 

 pize. In its geographical distribution it differs strikingly 

 from that of the reindeer in so far as it is now quite confined 

 to Greenland and arctic North America. It no longer inhabits 



* Soharfi, B,. F., " European Animals," p. 112. 

 t Brauer, A., " Die arktigohe Subregion." 



