IOO HISTORY OF THE EUROPEAN FAUNA. 



ones are confined to Scotland, whilst Ireland is occu- 

 pied chiefly by southern animals. This, however, is 

 only a very rough-and-ready method of sub-dividing 

 the British Islands into their component parts 

 according to the origin of their faunas. On closer 

 study such a division is found to be unsatisfactory. 

 The eastern species do not really stop at the Scottish 

 frontier, they range far into Scotland. Nor are the 

 northern forms confined to the latter country. Many 

 of them range into Ireland, and also into England. I 

 have constructed a map of the British Islands showing 

 approximately the boundaries of the northern, eastern, 

 and southern species (p. 7), but even this may not 

 altogether meet with the views of an ornithologist 

 or conchologist. For every group of animals the 

 boundaries would probably require to be marked 

 differently. There is also a good deal of overlapping, 

 so that the attempt to define the limits of the various 

 elements meets with great difficulties. But the map 

 represents, I think, fairly well the general impression 

 one receives as to the disposition of its component 

 elements, after a careful study of the British fauna 

 as a whole. 



The distribution of the British plants has been 

 worked out much more thoroughly than that of the 

 animals. It need not surprise us, therefore, that the 

 first attempt to separate the British Islands into 

 natural divisions was made by a botanist the late 

 Mr. Watson. As he himself pointed out, in making 

 these divisions he did not take into consideration the 



