16 
extreme position or not, it is certain that much enlightenment has 
been obtained by an analytical study of the “ antithesis ” between the 
two types of variation. 
With the rarest possible exceptions, two allied forms co-existing in 
the same area—especially if at the same period of the year, as 
emphasized by Mr. Tutt—can be demonstrated to be either structurally 
distinct or else freely syngamic; and it appears to me that the term 
“species” has, therefore, an absolutely definite meaning when applied 
to the working-out of a local fauna, but that it has no really definite 
meaning when applied to an assemblage of geographically sundered 
forms. Dr. Jordan argues at considerable length, and with a good 
deal of justice, that such assemblages ought to be regarded as single 
species, even if, at the confines of their area, they show some structural 
difference (as with the aforementioned Pa/nlio dardanus), provided 
always that in intermediate localities they intergrade. He shows the 
apparent absurdity of the alternative course, whereby the forms 
inhabiting the intermediate area, might be said to belong to two 
different species. But is such an anomaly really avoidable in every 
case ? Supposing the connecting link between two forms is not 
geographically intermediate, but that, on the other hand, the two allies 
(differing structurally) cover the same area, while the intermediate is 
more or less separated from them geographically—as I suggested at 
the outset—how can we then escape from the dilemma ? Prof. Ray 
Lankester’s “ Counsel of perfection ” will perhaps, ultimately, come 
to our aid; that is, we shall abolish the term species, give names to 
all the differentiable forms, geographical or otherwise, and say of this 
and that form that they are “ syngamic,” or syngamic in such-and- 
such a specified locality, or asyngamic everywhere. 
I fear I have been rather discursive, but the impression I want to 
leave is this : we can, and should, hope to be able to find out how many 
“ species ” of lepidoptera breed in Britain; but we need never expect 
to arrive at unanimity as to how many of their close allies in North 
America—which never do interbreed with them—ought to be called 
“co-specific” with them, and how many ought rather to be called 
“ representative species,” “ closely allied species,” etc. Ideally, I 
suspect every North American form ought to have a separate name, 
and then, when we arrive at Prof. Ray Lankester’s classifieatory 
millennium, every individual worker will be able to say, according to 
the results of his own researches, “ The European form, Lycaena 
( Celastrina ) argiolus, and the North American form, Lycaena ( Celastrina) 
pseudargiolus, agree in every morphological character which has yet 
been investigated,” or, “ The European form Cidaria ( Dysstroma ) 
truncata, and the North American form Cidaria (Dysstroma ) mulleolata, 
differ in such-and-such point of male genital armature,” and so on; 
instead of being expected, as at present, to say—and perhaps on data 
which future morphological research may overthrow—“ These two 
Lycaenids ( Celastrinas ), are co-specific, and the American form, as well 
as the European, ought to bear the species-name of argiolus. 
But if a “ species ” has so little objective existence, what shall we 
say of the “genus”? These criteria which have, however inadequately, 
helped us to determine our question regarding the units of classification 
in the former grade—precise morphological agreement, syngamy, 
XIX. 
