368 REVIEWS. 
variations in each of these, may be regarded as collateral with, or 
supplementary to, Mr. Allen’s highly interesting and suggestive a 
“ Examination of Certain Assumed Specific Characters in Birds.” a 
This constitutes Part IIT of the memoir, and is the nucleus of the a 
whole. Every paper of Mr. Allen’s which we have had the pleas- A 
ure of studying has plainly disclosed the drift of his views, and in 3 
this one his energies are focussed on an attempt to show that a a 
very large proportion of the forms we commonly designate by 
means of the binomial nomenclature ought not to be so designated. : 
The proposed reduction in our nominal lists is to be effected a 
mainly by discarding all names imposed upon “ geographical dif- a 
Jerentiation” among birds. We say this advisedly ; for, since no 
ornithologist upholds the practice of naming individual variations, — 
local or other climatic varieties are all that he has to fight against — 
in his present crusade. The attack is first made, very judiciously, — 
with an elaborate and interesting exposition of purely individual — 
variation in birds, based upon an examination of extensive series _ 
of specimens. 
Mr. Allen says (p. 188), that he has the material to “ disclose 
a hitherto unsuspected range of purely individual differentiation ;” 
but this we are not prepared to admit. Fully aware ourselves of 
the extent of variation that he demonstrates, we cannot presume 
that other ornithologists are less informed. Still we must, in the J 
same breath, do Mr. Allen the justice to add that he shows the — 
known wide range of both individual and climatic variation to be 
more extensively applicable than we practically consider it; ‘in — 
lustrates the fact with many examples. This is so true, that we 
wonder how Mr. Allen can unite Chordeiles Texensis with C. pop 
etue, while he keeps Rallus elegans and R. crepitans apart; for, in 
the latter case, the difference is solely in intensity, while in the 
former it is largely in style of coloration! Other color-varia-— 
tions, as those dependent upon age and season, are faithfully pre- 
sented ; but these have not, perhaps, on the whole, so much impor- — 
tance as the differences in size and proportion of parts, to which — 
he justly gives special attention. His admirable tables of meas 
