THE DISTRIBUTION OF SPECIES. 



197 



Europe. To the south the species increase in number 

 and variety ; the arctic regions are remarkable for what 

 they lack, yet the general character of the life is almost 

 unbroken over this vast district. Alfred Russell Wal- 

 lace refers to this unity of northern life in these words : 



"When an Englishman travels by the nearest sea 

 route from Great Britain to northern Japan, he passes 

 by countries very unlike his own both in aspect and in 

 natural productions. The sunny isles of the Mediter- 

 ranean, the sands and date palms of Egypt, the arid 

 rocks of Aden, the cocoa groves of Ceylon, the tiger- 

 haunted jungles of Malacca and Singapore, the fertile 

 plains and volcanic peaks of Luzon, the forest-clad moun- 

 tains of Formosa, the bare hills of China pass succes- 

 sively in review, until after a circuitous journey of thir- 

 teen thousand miles he finds himself at Hakodate, in 

 Japan. He is now separated from his starting point by 

 an almost endless succession of plains and mountains, 

 arid deserts or icy plateaus; yet, when he visits the 

 interior of the country, he sees so many familiar natural 

 objects that he can hardly help fancying he is close to 

 his home. He finds the woods and fields tenanted by 

 tits, hedge sparrows, wrens, wagtails, larks, redbreasts, 

 thrushes, buntings, and house sparrows, some absolutely 

 identical with our own feathered friends, others so 

 closely resembling them that it requires a practised 

 ornithologist to tell the difference. . . . There are also, 

 of course, many birds and insects which are quite new 

 and peculiar, but these are by no means so numerous or 

 conspicuous as to remove the general impression of a 

 wonderful resemblance between the productions of such 

 remote islands as Britain and Yesso." (Island Life.) 



A journey to the southward from Britain or Japan 

 or Illinois, or any point within the holarctic realm, 

 would show the successive changes in the character of 



