^38 



THE FLESH-EATERS. 



vorous mammals, that we might often be in 

 doubt where to place an animal of which only 

 the dentition was known. Other families, 

 such as the dogs and bears, appear to be 

 derived from the intermediate forms already 

 mentioned. But all these generations were 

 so clearly separated from one another in both 

 hemispheres by the end of the Eocene period, 

 that certain families could not develop at all 

 in one of the two, while others were enabled 

 to reach the highest stage of their develop- 

 ment. The Hyjenidaand Viverrida have not 

 been able to develop in the New World nor 

 the Procyonida in the Old, because the inter- 

 mediate forms from which these families might 

 have proceeded have been wanting since the 

 origin of the placental mammals. The 

 Canida, Felida, and Mustelida, on the con- 

 trary, have had fruitful branches in both 

 hemispheres. In this manner is explained, at 

 least in part, the present geographical distri- 

 bution with respect to the land-masses which 



were already isolated in early geological 

 periods. 



If this separation already existed during 

 the Tertiary period it does not follow that 

 migrations in the interior of these land-masses 

 could not take place, and that changes in 

 climate which occurred in the course of the 

 geological epochs should not have had a 

 great influence on the present distribution of 

 the Carnivora. In consequence of these 

 changes the hyaenas, which still inhabited 

 Europe in diluvial times, have since left it, 

 and the gluttons, which once advanced further 

 to the south, have subsequently again retired. 

 There is no doubt that many Felida, Canida, 

 Mustelida, and Viverrida, thanks to their 

 fleetness and energy, have been able to 

 spread themselves during geological periods 

 over wide stretches of territory, while other 

 more clumsy types remained pretty much 

 confined to the limits within which they 

 are still found. 



