340 HISTORY OF THE EUROPEAN FAUNA. 



It is somewhat similar to one which has recently 

 been strongly supported by Professor Nehring and 

 accepted by Professor Th. Studer and many others. 

 They have never made it quite clear whether the 

 pre-glacial fauna and flora are supposed to have 

 been absolutely destroyed by the glacial climate, 

 or whether part of them have been able to take 

 refuge somewhere in the south; but the great mass 

 of our Alpine plants and animals are believed to 

 have been derived from the Siberian invasion, which 

 I have fully described in the fifth chapter. This 

 invasion spread over the European plain, and when 

 the climate ameliorated, both animals and plants 

 migrated north and south to the mountains. This 

 view agrees with the earlier theory, except that the 

 adaptation to Alpine conditions would, according to 

 the former, have taken place since the close of the 

 Glacial period, during which time no such modifica- 

 tion or change of species seems to have been pro- 

 duced in other parts of the world. The characteristic 

 fauna of the Alps, as has been gathered from 

 the preceding pages, is mainly of Central Asiatic 

 rather than of Siberian origin. Migration to the 

 Alps took place by the Oriental route long before 

 the Siberian invasion. Some of the species of the 

 latter have penetrated to the Alps, but these Siberian 

 species have not given to the fauna of the highest 

 European mountain range the striking character with 

 which we all associate it. 



Before concluding this chapter, a few remarks on 



