ths atte ee eRe ee aM oe oes 
REVIEWS. Sit 
species, we have a right to demand that he should say what a spe- 
cies is. But this is all we have: —‘‘ The question of species and 
of specific synonymy is simplified to this : that whenever two forms 
which have both received specific names are found to intergrade, 
the more recent name shall become a synonym of the older.” (p. 
245.) Simple and easy as this seems, it presents great if not 
insuperable obstacles ; and we will add just here, that this shifting 
of the question from the vital point, namely, the discussion of 
what a species is, to a superficial issue, namely, the propriety of 
imposing names upon this or that form, is not what we should 
have expected from a naturalist of Mr. Allen’s position. 
Following his rule we hold our nomenclature by a frail tenure 
indeed ; for nothing in biology is more certain than that the mul- 
titude of animals and plants now existing, are the ramifications of 
comparatively few trunks; and nothing is more unstable than in- 
tergradation which he proposes as a crucial test. To speak roundly, 
verything runs into something else ; not necessarily just now (though 
this is frequently the case), but at some period. ‘‘Species,” like 
some plants, are stoloniferous; they produce offsets that finally 
separate from their parent stock, and appear like distinct entities. 
Our positive specific forms — those that alone we should recognize, 
according to Mr. Allen — are simply those whose wide divergence 
has concealed or broken their connections with the original stem ; 
while all debatable forms (and these constitute a great part of our 
lists) are merely those that are in visible process of separation. 
When a form has diverged to the slightest appreciable degree, 
some ornithologists, like Brehm, for instance, label it with a bino- 
mial; most ornithologists, probably, wait till they think that this 
divergence is a settled thing not likely to revert; but nearly all 
will name with the connecting links before their eyes. Mr. Allen, 
however, like Prof. Schlegel, would virtually ignore the proc- 
ess of divergence, until it has reached a certain, or rather an un- 
certain, point, and effaced connections that once existed. We 
are opposed to this, and still plead for names, if only as ‘‘ conven- 
ient handles for facts” that it is of the last importance to bear in 
mind. Pure synonyms are pure trash, of course, and none detest 
them more cordially than ourselves ; but we insist upon the advis- 
ability, in the present stage of our science, of recognizing geograph- 
ical and some other differentiations by name.* No stronger 
* Not gap g” " apeetie » name, but some one additional word, with or without 
NATURALIST, VOL. V. 24 
