CHAPTER X. 
THE PALHARCTIC REGION. 
THIS region is of immense extent, comprising all the temperate 
portions of the great eastern continents. It thus extends from 
the Azores and Canary Islands on the west to Japan on the 
east, a distance not far short of half the circumference of the 
globe. . Yet so great is the zoological unity of this vast tract, 
that the majority of the genera of animals in countries so far 
removed as Great Britain and Northern Japan are identical. 
Throughout its northern half the animal productions of the 
Palearctic region are very uniform, except that the vast elevated 
desert-regions of Central Asia possess some characteristic forms ; 
but in its southern portion, we find a warm district at each ex- 
tremity with somewhat contrasted features. On the west we have 
the rich and luxuriant Mediterranean sub-region, possessing many 
peculiar forms of life, as well as a few which are more especially 
characteristic of the Ethiopian region. On the east we have the 
fertile plains of Northern China and the rich and varied islands 
of Japan, possessing a very distinct set of peculiar forms, with 
others belonging to the Oriental region, into which this part of 
the Palearctic region merges gradually as we approach the 
Tropic of Cancer. Thus, the countries roughly indicated by the 
names—Northern Europe, the Mediterranean district, Central 
and Northern Asia, and China with Japan—have each well- 
marked minor characteristics which entitle them to the rank of 
sub-regions. Their boundaries are often indefinable ; and those 
here adopted have been fixed upon to some extent by considera- 
