62 THE ZOOLOGIST. 



A PLEA FOE THE FUKTHER RECOGNITION OF 

 SUBSPECIES IN ORNITHOLOGY. 



By W. Ruskin Buttekfield. 



When Linne proposed his great reform of binomial nomen- 

 clature species were universally believed to be perfectly circum- 

 scribed and immutable groups. Men's ideas of species have, 

 however, like species themselves, undergone changes. But it 

 is still the usual practice in this country to treat as " species " 

 all forms that in the opinion of the describers are separable, 

 no lower classificatory unit being recognized. It can hardly be 

 doubted that this conservative method of treatment has greatly 

 hindered the progress of ornithology, and in the following 

 remarks I venture to urge the importance of paying due regard 

 to subspecies. 



By subspecies are here meant the recognizable geographical 

 forms or components of a species, whether these components 

 occupy continuous or discontinuous areas — in other words, 

 whether they intergrade or do not intergrade. Some orni- 

 thologists who admit subspecies restrict the term to intergrading 

 forms, while forms that do not intergrade are elevated to specific 

 rank. On the other hand, separate treatment is not accorded 

 geographical intergrading forms by ornithologists who refuse 

 recognition to subspecies. 



The evidence of subspecies is clear enough when a large and 

 representative series of a widely-ranging species is examined, 

 e. g. Certhi a familiar is, Galerida cristata, Parus palustris, Aluco 

 Jlammea. The most cursory examination shows that such an 

 assemblage is not an homogeneous assemblage, and when the 

 specimens are arranged geographically the whole series is seen 

 to break up into a number of subordinate groups, the proper 

 delimitation of which is only possible when a large number of 

 specimens are available, and when they are derived from many 

 portions of the range. Of course, the number of examples of a 

 widely-distributed species to be found in any collection bears but 



