REVIEWS. 368 



variations in each of these, may be regarded as collateral with, or 

 supplementary to, Mr. Allen's highly interesting and suggestive 

 " Examination of Certain Assumed Specific Chai-acters in Birds." 

 Tills constitutes Part III of the memoir, and is the nucleus of the 

 whole. Every paper of Mr. Allen's which we have had the pleas- 

 ure of studying has plainly disclosed the drift of his views, and in 

 this one his energies are focussed on an attempt to show that 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 

 mainly by discarding all names imposed upon '■^geographical dif- 

 ferentiation" 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 

 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 

 short, that he proves what we are accustomed to regard as excep- 

 tional to be the rule. Several prominent phases of individual vari- 

 ation are discussed. In color, he holds that it is solely a matter 

 of intensity, " while in allied species there is almost always an 

 appreciable variation in the style of coloration" (p. 187), and il- 

 lustrates the fact with many examples. This is so true, that we 

 wonder how Mr. Allen can unite Chordeiles Texensis with C. joop- 

 etue, while he keeps Rallus elegans and M. 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- 



