204 Recent Ornithological Publications. 
an expedition from Transbaikalia to tbe Amoor and back in 
1855; and by Herr Maximowicz, a botanical collector in tbe 
employ of the Imperial Botanical Gardens of St. Petersburg, who 
was also travelling on the Amoor from 1854 to 1856. The whole 
number of species thus embraced in the body of the work is 190. 
At the end of the volume, however, before conclusions are drawn 
as to the general character of the ornithology of this country, 
extended lists are given of other species attributed to the same 
locality by different authorities, and of such as might have 
been expected to have been found there from their occurrence 
in localities not far distant, so that every endeavour has been 
made to render this volume a complete guide to the ornithology 
of this part of the world. 
With the general conclusion drawn by Dr. v. Schrenck from 
these elements, “ that the prevailing character of the Avifauna 
of Amoorland is Europao-Siberian,” or, as we should prefer call¬ 
ing it, PalvEarctic, we fully agree; but when we come to dis¬ 
cuss the foreign elements which are certainly present, though to 
a very limited degree, we must say a few words upon the method 
which our author has followed in treating of his species. On 
the difficult question where we are to draw the line between 
“ species ” and “ local varieties,” we have on one side the views 
of such naturalists as Mr. Wallace, who broadly state that it 
matters not how small the difference is between two represent¬ 
ative species provided it be constant, and on the other the prac¬ 
tice of many eminent zoologists, who are accustomed to class 
together a large number of species, usually considered as distinct, 
as merely local or climatic varieties of one typical form. Between 
these opposite views there is certainly ample room for every 
shade of opinion. Every naturalist, indeed, has his own ideas 
on this matter. The fact is, that the amount of difference 
requisite to establish specific distinctness between two sets of 
individuals is, as has been well maintained by an eminent writer, 
whose views are adverse to the real existence of species, “a 
matter of opinion,” and we should therefore be very careful in 
blaming writers whose ideas on this point may be at variance 
with our own. But, nevertheless, this much is to be said upon 
the subject, the truth of which we presume few will venture to 
