PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 63 
the islands during the period previous to which they received their pre- 
sent fauna and flora were totally covered by the sea, and that since 
that time they have not been connected with the mainiand on either 
side. From this it would follow that none of the species cceurring 
here are trueindigenes. They evidently immigrated, especiaJly and more 
regularly from the west, from Asia, by means of prevailing winds, cur- 
rents, and the driftwood carried by these, and more accidentally from 
the east, from America. That the inhabitants, more independent of 
those circumstances, likewise show nearer relationship to the Asiatic 
fauna is partly due to the shorter distance, this being only 100 miles 
from the nearest cape of Kamtschatka, Cape Kronotski (which by the 
Russian man-of-war Vestnik this year has been found to be situated 20 
miles more to the westward than given in the charts), while the nearest 
island of the Aleutian chain, Attu, is twice as far off; and partly to the 
effort of the Asiatic fauna to extend beyond its own limits. Itisa well- 
known fact that the Asiatic fauna is in a continuous and comparatively 
rapid motion towards the west, especially in northern Europe. But it 
seems to me that a similar movement takes place in the eastern part of 
Asia, only in an opposite direction, the proof of which I find in the not 
inconsiderable number of exclusively palearctic forms in Alaska, espe- 
cially among the birds. I here enumerate only Cyanecula, Saxicola, 
Phyllopneuste, Pyrrhula, Parus obtectus, Cab., ete. 
It istrue that the zojgeographical regions overlap each other near their 
borders, but it is a remarkable fact that America contributes but very 
little to the fauna. Thus it is probable that ere long we will detect still 
more Asiatic forms in Alaska, and that hereafter it will be necessary to 
register as residents such species which at present are known only as 
temporary or casual intruders. 
The occurrence of species peculiar to the islands (and I have no doubt 
that the final revision of the material collected by me will make known 
several new ones) will not invalidate what I have stated above with 
regard to the want of indigenous animals and plants. Their origin is 
due merely to variability in connection with isolation and time. 
As to the plants I shall be very brief, as I am not a botanist. I limit 
myself to the remark that I find the general character of the flora very 
much like that of the treeless regions of Northern Europe, the most dis- 
crepant features being the splendid Rhedodendrons (kamtschaticum and 
chrysanthum) and the Saranna lily (Fritillaria saranna). Still closer, of 
course, is the resemblance to the plants of Kamtschatka, especially to 
those in greater altitudes. The plants of both islands are, I think, 
identical, but the manner of their immigration very likely has caused 
the occurrence of some species in one island which are absent in the 
other. Thus I have from Copper Island a small but very conspicuous 
Viola with yellow flowers (much resembling the yellow variety of V. 
tricolor),a plant which I found also in Petropaulski, but not here on 
Bering Island. 
