103 ToKio Kaeuraki 



Judging from the data on tlie distribution of reptiles and amphibians, 

 Hatta maintains that it may be advisable to put great stress upon the 

 line passing through the Soya strait, instead of the Tsugaru strait. 

 Considering the Tsugaru strait as the southern boundary of the 

 Eurasian elements, as well as the Soya strait as the northern bounda- 

 ry of the Eastasian ones, Matsumoto infers that Holvkaido presents us 

 with the mixed fauna of the two different types. Thus, the question 

 is subject to further investigation. For the sake of convenience, I 

 follow here Blakiston's view. 



To judge from the facts just given, the Japanese archipelago may 

 be divided into the following faunal areas :- 



1. Palaearctic region. 



a). Eurasian subregion, consisting of the Kuril e group, Sagha- 



lien, and Hokkaido, 

 b). Eastasian subregion, including Korea and Japan proper, the 



latter of which consists of Honshu, Shikoku, and Kyushu. 



2. Oriental region, comx'rising the islands of Formosa and Loochoo. 



The Kurile Group. — Extending in a north-westerly direction 

 from Hokkaido to Kamchatka lies the Kurile group, which comprises 

 some barren islands. In order to have a clear concej)tion of the 

 X)eculiar character of its fauna, we may divide the group by the 200 

 metre line into three subgroups, the northern (Shimushyu-Shiashkotan), 

 the middle (Eaikoke-Shinshir), and the southern ( Urup-K una shir ) . 

 Owing to the incomplete state of our knowledge it is hardly possible 

 to pursue their faunal relations satisfactorily, but I think enough 

 examjjles have been given to throw some light on this subject. 



Of about 22 species of mammals which are at present known 

 from this group,- two appear to be endemic and are spread over the 

 two northern subgroups. Such are Biicrotus uchidae and Mus hurilensis, 

 of which the former is most closely related to that found in Kam- 

 chatka. On the other hand, the remaining species, with the exception 

 of some introduced forms, belong to those which occur in Hokkaido, 

 and are found couiined to the southern subgroup, for example, 

 Eutamias cmaticus, Myotis mystacinv.s, Pipistrellus abramtcs, Ursns 

 arctos yesoensis, Lidra Intra htra, etc. The Kurile red fox {VuJpes 

 anadyreyibis spJendidissimus) and the sable (Martes zihellina) are 

 in^portant fur -bearing species, forming the basis for a most extensive 

 commerce. The former abounds in the northern subgroup, and the 

 latter in the southern. 



