98 HISTORY OF THE EUROPEAN FAUNA, 



continent. This went on, and not for a comparatively 

 short space of time, as in the case of the Siberian 

 invasion ; the immeasurable ages which passed, 

 whilst several of the Tertiary epochs dawned upon 

 Europe, witnessed an almost constant stream of 

 Asiatic immigrants pouring in upon us. Europe 

 returned her own products in exchange, but they 

 must have been scanty in comparison to the enor- 

 mous number of species which have undoubtedly 

 originated in Central and Southern Asia. Very 

 many of the widely distributed forms in the British 

 Islands are of Oriental origin. Among these are 

 also the cosmopolitan species, such as the Barn 

 Owl (Strix flammed] and the Painted Lady Butter- 

 fly ( Vanessa cardui}. A great number of our 

 British Mammals, Birds, Butterflies, and Beetles have 

 come to us with the Oriental migration. But, as 

 I shall explain in the special chapter devoted to it, 

 the earlier migrants from the south-east found their 

 northward progress barred by a great sea which 

 stretched through Central Europe from west to east. 

 The Mediterranean was then divided into two smaller 

 basins. On their arrival in Greece, which was then 

 connected with Asia Minor and Southern Italy, 

 the Oriental migrants seem to have turned westward, 

 skirting the shores of the Mediterranean. When they 

 finally reached Spain, many then changed their course 

 northward (see Fig. 5, p. 117) and wandered to the 

 British Islands with the Lusitanian animals which 

 came from South- Western Europe. 



