THE TAXONOMIC UNIT 
49 
Along with the subspecies unit comes trinomial nomenclature. 
The greatest objection to this lies, perhaps, in the difficulty in- 
volved, and the consequent restriction in use. It will not help 
to say that subspecies and trinomials are for the use only of 
taxonomic experts, and that others may be content with the 
species unit. There must be a common ground in order to pro- 
mote cooperation and prevent misunderstanding and confusion. 
The taxonomist has no license for erecting a system which is un- 
related to other biological fields. It must be emphasized that 
taxonomy and nomenclature are tools of the biologist, and not 
a branch of science sui generis; they serve no useful ends apart 
from their relation to other branches of biological knowledge. 
Thus the biologist has a right to discuss the manner in which 
taxonomy is helpful, or otherwise. 
Other objections which have been offered to the subspecies 
unit and trinomial nomenclature may be summarized as follows: 
(a) There is usually a variance in the judgment of the ex- 
perts on the relative value of the minute characters upon which 
subspeciation is based. 
(b) Subspecies and trinomials represent no stopping place, but 
lead directly to tetranomials and polynomials. 
(c) Such ultra-refinement thwarts the purpose of any system 
by introducing uncertainty and lack of precision in the ends 
which taxonomy is designed to serve. For the sake of argument 
we might grant that the expert taxonomist might be able to 
work precisely even with subspecies, but we would immediately 
reply that that, in itself, would serve no useful end. When we 
split our subspecies one or more times we will be back to the 
good old pre-Linnaean days when, as pointed out by Loomis,® the 
Mockingbird was distinguished by the name of Turdus minor 
cinero-albus non-maculatus. Yet this is simplicity in comparison 
with the multiplicity of trinomially designated forms which only 
a half dozen persons in the world, perhaps, are qualified to de- 
termine. 
(d) As urged by some of the British ornithologists when the 
trinomial system was proposed by the American school, perhaps 
the greatest objection is its liability to abuse. That such abuse 
has been practiced one example will suffice to show. In the 
recent pages of the leading American ornithological journal a new 
subspecies of teal duck was described, in which the differential 
character was the extension of a white crescentic patch from the 
8 The Auk, XX, pp. 294-299, 1901. 
