142 THE WANDERINGS OF ANIMALS [CH. vi 



' in the larger areas and more efficient workshops of 

 the north/ and the balance is in favour of Asia as the 

 cradle of modern mammals. 



Is it an idle dream to think of the future? 

 A survey of the past reveals the vanishing of whole 

 faunas from extensive countries, which were then re- 

 peopled by other forms from elsewhere. What has 

 happened before, may happen in times to come. 

 Countless groups, once flourishing, are no more ; 

 many others have had their day and are now on the 

 decline, whilst others are flourishing now, are even on 

 the increase and seem to have a future before them. 

 Such favoured assemblies are the toads and frogs, 

 lizards and snakes, Passerine birds and rodents, mostly 

 the small-sized members of their tribes ; the days 

 of giants are past. All this has happened in the 

 natural course of events, without the influence of 

 man, who only within most recent times has become 

 the most potent and destructive factor to the ancient 

 faunas of the world. 



