632 A CENTURY OF PROGRESS IN THE NATURAL SCIENCES 



In that same year, in the second paper of his budding career, Ridgway proposed 

 that, if two populations are extremely different, even though they are connected 

 by a chain of intermediate forms, they should be considered full species. This 

 concept showed the effects of the morphological species definition coupled with the 

 dawning realization that geographic variation had to be taken into consideration. 



One of the most able American biologists of this period was Joel Asaph 

 Allen (b. 1838, d. 1921). In 1871 Allen demonstrated the correlation between 

 coloration and humidity in birds, the darker populations being associated with 

 high humidity, the lighter with aridity. He proposed that, instead of applying 

 a name to each local population, species should be diagnosed in relation to the 

 laws of variation. This was similar to von Gloger's (1833) suggestion. In 1877 

 Allen opposed the invocation of natural selection to explain the genesis of species 

 in favor of a Lamarckian concept of the direct influence of temperature, hu- 

 midity, food, etc. 



Some of these developments hardly seem like "progress" when viewed from 

 the vantage point of 1953, but they are evidence of the problems which were 

 under attack by the systematists of the time, whose investigations were soon to 

 produce more durable results. 



In Elliot Coues (b. 1842, d. 1899) American ornithology found its genius. 

 It was he who took the decisive step in the right direction. In 1872 in his famous 

 Key he adopted the viewpoint that geographically complementary forms which 

 were clearly closely related were subspecies of one species, regardless of the 

 degree of difference between the extremes. Coues used the abbreviation "var." 

 to indicate geographic races. The same system was employed by Baird, Brewer, 

 and Eidgway in 1874 and remained in effect until 1881, when Ridgway took the 

 final step to a true ternary nomenclature. 



There was a vast difference between the viewpoint of Schlegel and that of 

 Coues and Ridgway. The former believed in the constancy of species and used 

 the trinominal to designate deviations from the "type" of the species. The 

 Americans in contrast were stanch Darwinians and for them the third name 

 served to identify an incipient species. Baird was their mentor and he believed 

 that if the connecting links should become extinct the previously intergrading 

 forms would develop into distinct species. 



Remarkably enough there was virtual unanimity among the leaders in syste- 

 matic ornithology in the United States regarding the concepts and usage of 

 ternary nomenclature. Coues, the one among them with truly cosmopolitan 

 views, decided to go to England to present the case for trinominalism and to 

 urge the adoption of uniform rules. His optimism was not shared by Ridgway 

 (Harris, 1928, p. 51), who felt that little would be gained. On July 1, 1884, 

 Coues met with a group of the outstanding zoologists of England at the British 

 Museum in South Kensington. As Ridgway had predicted, the proposals met 

 with little enthusiasm. Only Henry Seebohm (b. 1832, d. 1895) recommended 

 their acceptance but he was opposed by such potent adversaries as R. Bowdler 

 Sharpe and P. L. Sclater. Coues returned home in defeat. 



In 1885 the Committee on Nomenclature of the American Ornithologists' 

 Union officially accepted the concept of Coues and Ridgway. The motto of the 

 time was "intergradation is the touchstone of trinominalism." 



In Europe the battle had barely begun. Seebohm (1887) had pointed out 



