GEOGRAPHICAL DISTRIBUTION 343 



since by Gloger,i 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 diuing 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 ^vriter knows, 

 abstained from theorizing upon them. His example was followed 

 by many of the enthusiastic and painstaking ornithologists who 

 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 



^ Das Abandern der Vogel durch Einfiuss des Klimas. Breslau : 1833. 



- 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. Zool. 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 Sac. 

 Nat. Hist. XV, pp. 212-219). He also notices the fact, since observed in i-egard 

 to the Eed Grouse in Great Britain, that considerable variation may exist inde- 

 pendently of locality. 



^ 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. 



