A Allen on the Recognition of Geographical Forms. [January 



were merely local, intergrading, geographical forms, correlated 

 with special features or conditions of environment. 



During the three years including and following the year 1S71 

 ornithological opinion on the subject of species and subspecies, 

 or respecting the status of a large proportion of the birds of North 

 America, experienced a radical disruption. The first great wave, 

 which for generations had been increasing in volume and force, 

 met a barrier against which it recoiled and subsided with phe- 

 nomenal suddenness, giving place to a strong and sweeping 

 counter current. The key-note to the situation had been struck, 

 and after a brief period of wavering a happy medium course was 

 hit upon, which seemed to solve most of the difficulties that had 

 beset the general subject of species. This was no less than the 

 reduction of numerous so-called species to the rank of geographi- 

 cal races or subspecies, namely such as were found to intergrade 

 with other forms, or which it seemed probable, on general princi- 

 ples, might so intergrade. Immediately inveterate splitters became 

 bold lumpers, and the ornithological pendulum swung quickly 

 back with a momentum sufficient to carry it somewhat beyond 

 the vertical. The term ' var ' interposed between the name of 

 the original species (in the sense of the earliest described species) 

 and its various local ofishoots was the magic link which was to 

 connect and duly correlate the discordant bird elements of our 

 North American fauna. This, of course, was the origin and first 

 phase of our present trinomial system of nomenclature, which ten 

 years later was formally endorsed and adopted by the American 

 Ornithologists' Union. 



While this great step — little less than a revolution in its results 

 — was in the main in the right direction, it led to some rash con- 

 clusions, theoretical reasoning now and then overstepping the 

 hard line of facts. Consequently in a few instances species were 

 unduly merged, and it has been necessary to reconsider these hasty 

 rulings. The oscillation in the direction of unwarrantable lump- 

 ing, however, soon reached its extreme limit ; the pendulum settled 

 back, and for a time remained at what we may consider as very 

 nciir its normal point of equilibrium. For nearly a decade, dating 

 from 1S75, the deflections were slight and variable, now to one 

 side, and now slightly to the other. This period of comparative 

 stability includes the work of the A. O. U. Committee, in the 

 years 1883-84, on the status of the described forms of North 



