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 
