GEOGRAPHICAL DISTRIBUTION 343 
since by Gloger,! and perhaps as satisfactorily as the evidence at 
his command would permit. In North America the late Prof. 
Baird seems to have been the first to turn his attention to this 
topic, the importance of which gradually impressed itself upon him 
as the several collections of specimens made during the explora- 
tions for a railway-route to the Pacific Ocean came under his eyes. 
He was content to register the results, and, so far as the writer knows, 
abstained from theorizing upon them. His example was followed 
by many of the enthusiastic and painstaking ornithologists wha 
sprang up around him,? and they, rejoicing in a wealth of speci- 
mens such as had never before been amassed, have undeniably 
shewn that it was not lost upon them. With scarcely an excep- 
tion they too have exhibited as much caution in regard to specula- 
tions as did their venerated leader. The great fact was established 
that, given a species, especially of a Land-bird, which had a wide 
range on a continent, the variation exhibited by individuals from 
different localities is generally so considerable that it is hardly 
possible to predicate its amount, while almost every intermediate 
form may be found if the series of specimens be large enough. 
One of the first results which naturally followed was the abolition 
of a great number of what had hitherto passed as distinct ‘ species,” 
and the recognizing them as local forms, any two or more of which 
should be united under one heading. It is of course true that to 
some extent naturalists were already aware of the fact that “ miss- 
ing links” were from time to time found between what had borne 
an unsullied reputation as good “species” ; but this had happened 
in a comparatively small number of cases, whereas it now became 
plain that it was of very common occurrence. Moreover, some 
“laws” were more or less manifest—for instance, examples of a set 
1 Das Abiindern der Vigel durch Einfluss des Klimas. Breslau: 1833. 
2 These are too numerous to name ; but the labours of Mr. J. A. Allen can- 
not be passed without recognition. His essay ‘‘On the Mammals and Winter 
Birds of East Florida,” published in 1871 (Bull. Mus. Comp. Zoél. ii. No. 3), 
entered into details of part of this question more thoroughly than had been 
before attempted ; and the views therein expressed have been confirmed on 
additional evidence in his ‘‘ Notes of an Ornithological Reconnaissance of por- 
tions of Kansas, Colorado, Wyoming, and Utah” (op. cit. iii. No. 6), as well as 
in his ‘‘ Geographical Variation in North American Birds” (Proc. Boston Soc. 
Nat. Hist. xv. pp. 212-219). He also notices the fact, since observed in regard 
to the Red Grouse in Great Britain, that considerable variation may exist inde- 
pendently of locality. 
3 It could be wished, however, that the North-American ornithologists had 
not latterly, by many innovations in the established theory and practice of 
scientific nomenclature, rendered so much of their excellent work unintelligible 
to all but the expert, and not readily understood by him. This proceeding was 
the more extraordinary as it is so contrary to the practical character of citizens of 
the United States. 
