THE ALPINE FAUNA. 333 



due to the influence of man, but not altogether. 

 There is a constant struggle for existence going 

 on among the animals and plants themselves the 

 stronger and fitter species driving the less fit and 

 weaker into a corner, where they finally succumb. 

 This happens now just as it did in pliocene and 

 pleistocene times, and need not imply change of 

 climate. 



As soon as the Miocene sea to the north of the 

 mountains had retreated, a portion of the Alpine 

 fauna poured into the plain, and many species 

 have found their way to the British Islands, a few 

 to Scandinavia and Russia. Westward too, the sea 

 soon after retired and opened a way for those 

 Alpine species which were vigorous enough to extend 

 their range in that direction. South-eastward, of 

 course, a highway had long ago been open, and 

 Alpine forms which were able to migrate towards 

 the incoming Oriental stream, had no difficulty in 

 doing so. When they arrived in Greece, some turned 

 westward again and populated Sicily, Southern Italy, 

 Sardinia, Corsica, and Northern Africa, while others 

 crossed over to Asia Minor, which was then con- 

 nected with Greece, and wandered towards the 

 Central Asiatic or the Himalayan Mountains. 



But, as I remarked, few of the typical Alpine 

 species reached Scandinavia and Lapland. I have 

 already referred to the similarity between the North- 

 ern Scandinavian and the Alpine faunas in a pre- 

 vious chapter, and I have shown that this resemblance 



