CHAP, xviii.] JAPAN AND FORMOSA. 



379 



parallel to that of the great spotted kingfisher, already referred 

 to as found only in the Himalayas and Japan. 



Comparison of the Faunas of Hainan, Formosa, and Japan. — 

 The island of Hainan on the extreme south of China, and only 

 separated from the mainland by a strait fifteen miles wide, 

 appears to have considerable similarity to Formosa, inasmuch as 

 it possesses seventeen peculiar land-birds (out of 130 obtained 

 by Mr. Swinhoe), two of which are close allies of Formosan 

 species, while two others are identical. We also find four 

 species whose nearest allies are in the Himalayas. Our know- 

 ledge of this island and of the adjacent coast of China is not 

 yet sufficient to enable us to form an accurate judgment of its 

 relations, but it seems probable that it was separated from the 

 continent at, approximately, the same epoch as Formosa and 

 Japan, and that the special features of each of these islands 

 is mainly due to their geographical position. Formosa, being 

 more completely isolated than either of the others, possesses a 

 larger proportion of peculiar species of birds, while its tropical 

 situation and lofty mountain ranges has enabled it to preserve 

 an unusual number of Himalayan and Malayan forms. Japan, 

 almost equally isolated towards the south, and having a much 

 greater variety of climate as well as a much larger area, pos- 

 sesses about an equal number of mammalia with Formosa, and 

 an even larger proportion of peculiar species. Its birds, how- 

 ever, though more numerous are less peculiar; and this is 

 probably due to the large number of species which migrate 

 northwards in summer, and find it easy to enter Japan through 

 the Kurile Isles or Saghalien. Japan too, is largely peopled by 

 those northern types which have an unusually wide range, and 

 which, being almost all migratory, are accustomed to cross over 

 seas of moderate extent. The regular or occasional influx of 

 these species prevents the formation of special insular races, 

 such as are almost always produced when a portion of the popu- 

 lation of a species remains for a considerable time completely 

 isolated. We thus have explained the curious fact, that while 

 the mammalia of the two islands are almost equally peculiar, 

 (those of Japan being most so in the present state of our 



