48 
IOWA ACADEMY OF SCIENCE Vor,. XXVII, 1920 
assigned to specific rank. Thus, no matter how unlike A and 
D may become, the presumption of common origin, as evidenced 
by intergrades, prevents their recognition as distinct species. This 
principle (of intergradation) is untenable from a general biolog- 
ical viewpoint because it is inconsistent with the doctrine of 
evolution. It is, in fact, a vestige of the discarded doctrine of 
immutability of species. How specific rank can be granted to 
Lynx canadensis and Lynx ruffus, for instance, and then denied 
to the extremes of variation in the Great Horned Owl, merely 
because of the existence of intergrades, is a puzzle which puts a 
strain on one’s logical faculty. 
On the other hand, if the study of any group of subspecies or 
varieties would permit their arrangement into a radial system, 
the explanation would be in harmony with well-understood bio- 
logical principles, and with the facts of continuous variability. 
This system requires a prototype, hypothetical or known, upon 
which the name may be bestowed. The radial variates, continu- 
ous variations, are designated simply as varieties when it is nec- 
essary to distinguish them at all. Theoretically discontinuous 
variations produce species at once, and leave no intergrades. 
I believe that ornithological taxonomists have found it usually 
impossible to determine prototypes among subspecies; and they 
have been satisfied merely to catalogue different forms which in- 
dividual opinion may regard as having subspecific rank.® 
What is to be gained, of value, by naming continuous varia- 
tions, or any particular assemblage of continuous variations, such 
as a variety or geographic race? Will, it not weaken an other- 
wise fairly satisfactory system of nomenclature? It is quite true 
that any one of them may represent an incipient species. And 
it is easily conceivable that any one may proceed in the devel- 
opment of still further unlikeness from the form with which it 
may be most closely related. The incipiency of this sort of thing 
seems to be too small a matter to be provided for in a nomen- 
clatural system. As Loomis says, “In trying to manufacture a 
nomenclature for birds of remote ages, past and future, are we 
not putting an impediment in the way of the study of existing 
birds?” ^ 
6 It is true that a committee of the American Ornithologists’ Union has acted as 
a court which accepts or rejects proposals of new forms of North American birds; 
for some years the rulings of this committee were satisfactory and generally accepted. 
More recently the committee has not, apparently, been functioning. It is assumed that 
the flood of “revisions,” with a perplexing array of newly proposed subspecies, has 
laid upon this committee an impossible task. It seems, at least, that such must be 
the inevitable outcome of the application of the principles of intergradation, subspecies, 
and trinomial nomenclature. 
7 The Auk, XX, page 299, 1903. 
