654 WATER-BIRDS OF JAPAN. 



to remind readers of this paper that the chain of islands forming that 

 country politically, can by no means be considered so homogeneous zoo- 

 logically ; nor would it be in reason to do so, even did we not know that 

 while the resident fauna of the main or middle island is, to a consider- 

 able extent peculiar, that of Yezo is mostly Siberian, while the Bonins 

 and Liu-Kins produce some local forms, in the latter mingled with For- 

 mosan or Chinese. Moreover, we find an indication of some degree of 

 peculiarity attaching to the southwestern portion of the main island and 

 Kiushiu, which adjoins it, with a trace — in birds, at least — of Chinese. 

 Besides this, it is noticeable that some migratory birds — non-oceanic — 

 have been found on the Kurils and Yezo, but not on the main or south- 

 ern islands; and as these are species which summer in Kamtschatka and 

 winter in China, their non-occurrence south of the Strait of Tsugaru 

 might indicate a line of migration across the Sea of Japan from Yezo 

 to the mainland of the continent, possibly an ancient migration route. 

 This seems, however, far from probable, for we know of other birds 

 which do migrate along the Kurils (from Kamtschatka ?) which pass 

 through the whole of Japan. Mr. Stejneger has enlarged upon the ab- 

 sence of certain Ja})an birds in Kamtschatka, and the occurrence there 

 of continental species unknown in Japan (si)eaking, of course, of migra- 

 tory birds), and he is no doubt right in believing that the bare volcanic 

 Kurils would not be a favorite route for many kinds. In addition, it 

 must be borne in mind that such a line is not a direct route northwards 

 from Japan, for the Kurils stretch ofi" northeastward, while a due north 

 line runs from Yezo, through Sakhalin, to the mouth of the Amur, and 

 is over wooded land. This would be the most natural one, even sup- 

 posing the Kuril Islands to have existed from a remote geological 

 period, which is contrary to the opinions held by geologists. More- 

 over, Mr. Stejneger has shown it to be probable that certain birds reach 

 Kamtschatka from the region south of Lake Baikal, while some others 

 which pass along the western shore of the Okhotsk Sea do not pene- 

 trate Kamtschatka, but continue their journey north and east of it, 

 because it is a peninsula with its point to the southward. It is probable, 

 therefore, that few birds take the line of the Kurils as a migration route, 

 although this is, from the scanty material at hand, little more than spec- 

 ulation, and should not perhaps have been entered into, save to draw 

 the attention of collectors to the necessity of securing specimens from 

 all localities and submitting them for careful identification, in order that 

 those finely-drawn characters which sometimes distinguish races of the 

 same species may be discovered, and lead to precise conclusions on the 

 interesting subjects of migration and distribution. 



