CHAP. XVIII.] 
JAPAN AND FORMOSA. 
371 
The spotted kingfisher, indeed, affords us one of the best ex- 
amples of that rare phenomenon — a species with a discontinuous 
range; for although an island is considered, for purposes of 
distribution, to form part of one continuous area with the 
adjacent continent (as when a species is found in France and 
Britain, or in Siam and Borneo, we do not say that the area of 
distribution is discontinuous), yet in this case we have to pass 
over three thousand miles of land after quitting the island, 
before we come to the continental portion of the area occupied 
by the species. Referring to our account of the birth, growth, 
and death of a species (in Chapter IV.) it can hardly be doubted 
that the Geryle guttata formerly ranged from the Himalayas to 
Japan, and has now died out in the intervening area owing to 
geographical and physical changes, a subject which will be 
better discussed when we have examined the interesting fauna 
of the island of Formosa. 
The other orders of animals are not yet sufficiently known to 
enable us to found any accurate conclusions upon them. The 
main facts of their distribution have already been given in my 
Geographical Distribution of Animals (Yol I., pp. 227-231), and 
they sufficiently agree with the birds and mammalia in showing 
a mixture of temperate and tropical forms with a considerable 
proportion of peculiar species. Owing to the comparatively 
easy passage from the northern extremity of Japan through the 
island of Saghalien to the main land of Asia, a large number of 
temperate forms of insects and birds are still able to enter the 
country, and thus diminish the proportionate number of peculiar 
species. In the case of mammals this is more difficult ; and the 
large proportion of specific difference in their case is a good in- 
dication of the comparatively remote epoch at which Japan was 
finally separated from the continent. How long ago this sepa- 
ration took place we cannot of course tell, but we may be sure 
it was much longer than in the case of our own islands, and 
therefore probably in the earlier portion of the Pliocene period. 
Formosa. 
Among recent continental islands there is probably none that 
surpasses in interest and instructiveness the Chinese island 
B B 2 
