720 Mr. J. Lewis Bonhote : SuJ>spefies [Ibis, 



XXXVII. — Subspecies and their part in Evolution. 

 By J. Lewis Bonhote, M.A., M.B.O.U. 



Mr. LooMis's' letter in 'The Ibis' (1920, p. 964) on sub- 

 species contains many orains ol: sound connnonsense, which, 

 if it only makes us pause for a few moments to consider 

 what subspecies really are, how they arise, and whither their 

 recognition is leading us, will have had a most beneficial 

 effect. It must be remembered — and the fact is too often 

 forgotten' — that nomenchiture is a means to an end, and not 

 the end itself. In order to be able to handle the vast array 

 of facts presented by a study oE Nature, naturalists have 

 invented a system whereby relationships between various 

 groups are roughly shown by methods of grouping and 

 naming; and up to some 20 years ago the "species" was the 

 smallest " item " in that system. The object of this system, 

 however, was not merely to enable us to arrange our collec- 

 tions in cabinets, but that, having arranged them in some 

 sort of a natural order, we might attempt with greater ease 

 to unravel some of the mysteries of Nature's laws. I am 

 not prepared to say that such a " unit" as a species actually 

 exists in Nature. When it does it must have been brought 

 about either because that species arose as a discontinuous 

 variation, or because the connecting series of small varia- 

 tions have been lost so as to leave it without any obviously 

 near relatives. This latter is the case, as we know, with 

 many present-day species, and thus is formed what Mr. 

 Loomis calls a " fundamental bird unit," although I do not 

 agree with him that they are in any way "fundamental"; 

 nevertheless, for practical purposes, they may be considered 

 as " units." 



Of late years the accumulating of larger and more care- 

 fully collected series has shown us that many of what were 

 previously considered merely as sporadic varieties are in 

 reality definite phases common to all individuals of a par- 

 ticular species in a certain area; and that such a form 

 intergrades gradually into the form which happens to be 

 next it geographically. These came to be recognized as 



