CHAP. XVTII.] 



JAPAN AND FOKMOSA. 



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 Ceryle 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 (Vol 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. 



FOEMOSA. 



Among recent continental islands there is probably none that 

 surpasses in interest and instructiveness the Chinese island 



B B 2 



