292 THE AMERICAN NATURALIST. [VoL. XXXIII. 
plished seems to be a matter of indifference to some ultra- 
progressive naturalists. It is as though a geographer, having 
learned that a certain region is slowly subsiding, should proceed 
to name the hills as islands, and publish his book revised for the 
next geologic period. Such a procedure would be, to say the 
least, misleading, both for the present and future generations. 
This is the third type of “ species,” very much in evidence at 
the present day. Although the designation by name of the 
various prominences or arms of a diversified island is desira- 
ble, even before the expected separation occurs, the prophetic 
tendency should, in the interest of historical accuracy, be 
curbed to the extent of distinguishing in category between 
groups which are already segregated in nature and those 
which are not. One naturalist refers to an entire island asa 
species, while another divides it into numerous parts which he 
still calls “species.” Now these parts may be as abundant 
in individuals, and their extremes may show differences even 
greater than those separating completely isolated species, but 
by treating them as already distinct we ignore the existence of 
intermediate forms and proceed as though degree of apparent 
difference were an index of segregation or a taxonomic sub- 
stitute for it. The theory that the formation of species 
through differentiation and segregation is proceeding continu- 
ously throughout nature has too often served as a warrant fora 
complete confusion of issues, with the natural result that some 
writers have shown more frankness than perspicacity in assum- 
ing the position that species are among the things “past find- 
ing out.” 
As if to solidify the confusion and justify this attitude, the 
naturalist is called to deal with a rapidly increasing number of 
man-made perversions, or at least diversions of nature. We 
assemble from different continents species of undoubted dis- 
tinctness and absolute segregation in nature, and produce 
hybrids which nature would never have formed and would not 
now permit to exist except under human auspices. Some nat- 
ural species, too, have shown themselves wonderfully susceptible 
of change through the influence of selection, so that the honest 
advocate of a general specific concept finds himself under the 
