SIBLEY: ORNITHOLOGY 633 



with keen insight that English ornithologists, while they accepted evolution in 

 theory, were failing to utilize it as a working hypothesis. He urged the adoption 

 of ternary nomenclature to differentiate nascent forms from "complete" species. 

 Seebohm also was the first ornithologist to recognize the importance of isolation 

 in species formation. He understood clinal variation and applied the subspecific 

 concept solely to variation which could be defined geographically. 



In Germany there were some who gave trinominalism a trial but, except for 

 Ernst Hartert (b. 1859, d. 1933), their sponsorship was carefully qualified. In 

 1891 Hartert went to England and in 1892 he became the director of the Tring 

 Museum, the remarkable private museum of Walter Rothschild (b. 1868, d. 

 1937). After Seebohm 's death in 1895, Hartert was the only ornithologist in 

 England consistently applying trinominals. Hartert expanded the subspecies 

 concept to include slightly differentiated forms, even though actual intergrades 

 were not present. Thus insular races were included in the concept and the re- 

 quirement of intergradation was replaced with a biological interpretation of 

 the situation in nature. 



For several more years the advocates of ternary nomenclature were to be 

 looked upon as traitors but gradually they gained disciples. By 1901 Hartert 

 was joined by several authoritative workers, the most effective being Carl E. 

 Hellmayr (b. 1878, d. 1934). In 1903, in the introduction to his mighty work 

 on palearctic birds, Hartert defined subspecies as geographically separated forms 

 of the same species which are characterized not by the minor degree of the dif- 

 ferences between them, but by differences which are related to geographical 

 separations. 



The publication of Hartert's book marked the turning point, although both 

 Sclater and Sharpe still held out. In 1909 Sharpe called the ternary system 

 ''destructive" and gloomily predicted that all zoologists who employed it would 

 find themselves overburdened with names. He agreed that subspecies did occur 

 in nature but held that the binary system was sufficient for all requirements. 

 Putting his belief into practice Sharpe raised to full species all those forms 

 described as subspecies and thereby attained the high number of 18,939 species 

 in his Haiid-list (5:xii, 1909). The discrepancy between that number and the 

 recent count by Mayr and Amadon (1951) of 8,590 species is mostly due to the 

 difference in application of the species concept. 



By 1912 the battle was won. The Hand-list of British Birds (Hartert, et al.) 

 used trinominals and caused little complaint. There followed a period of re- 

 evaluation during which many species were suppressed to the rank of subspecies 

 and descriptions of new subspecies appeared in increasing numbers. Now that 

 the nomenclatural practice was established it was inevitable that improvements 

 in the causal interpretation of geographic variation and its relationship to spe- 

 ciation would follow. 



As early as 1900 Otto Kleinschmidt (b. 1870) had recognized that the new 

 concept implied that each species was composed of geographically complemen- 

 tary forms. Kleinschmidt opposed the view that subspecies were incipient spe- 

 cies and sought to bridge the gap between the adherents of the Linnaean species 

 and those who believed in the nascent character of subspecies. His proposal of 

 the term "Formenkreis," to designate a geographically complementary series of 

 related forms was an attempt to emphasize the distinction between the new con- 



