10 HISTORY OF THE EUROPEAN FAUNA, 



several geological epochs, and have witnessed vast 

 geographical revolutions in their immediate surround- 

 ings, whilst mammals are comparatively short-lived. 

 Being driven from one country to another, and ex- 

 posed to innumerable enemies, new types appear and 

 old ones rapidly vanish ; in fact, there are almost 

 constant changes in the mammalian fauna as we 

 pass from one epoch to another. 



I have until now referred more particularly to the 

 British fauna and the North European in general, 

 because the history of our own animals interests 

 us all more than those of any other European area. 

 It is, moreover, preferable to commence our inves- 

 tigations into the origin of the European fauna 

 by the study of a small district. This should, if 

 possible, be an island. If we took a slice of the 

 continent like France or Germany, we should find 

 the problem more complex. Instead of choosing 

 the British Islands, we might, however, take an island 

 like Corsica or Sardinia. In either of these we should 

 discover peculiarities in the composition of their fauna 

 precisely similar to those which I have indicated to 

 be present in the British fauna. We should find 

 probably a more striking endemic 1 element, which 



1 The term endemic will be employed throughout this work as applied 

 to species peculiar to a country and not found elsewhere. Autoch- 

 thonous will be used in speaking of a species which has originated in a 

 country to which, however, it is not peculiar ; e.g. , the Chamois is an 

 autochthonous Alpine species, but occurs also in the Pyrenees and 

 Caucasus. An indigenous species is one native to a country, as 

 opposed to the term " introduced," and is applicable to all species 

 v\hich have reached it by ordinary migration. 



