"Now, if any such structure as this occurred in a wild species, and if any one were to ask what is the use of it, those who rely on the argument from ignorance would have a much stronger case than they usually have; for they might point to the cartilage supplied with muscles, and supporting a curious arrangement of bristles, as much too specialized a structure to be wholly meaningless. Yet we happen to know that this particular structure is wholly meaningless[99]." [99] Mr. Wallace deems the concluding words "rather confident." I was not, however, before aware that he extended his _a priori_ views on utility to domesticated varieties which are bred for the slaughter-house. If he now means to indicate that these appendages are possibly due to natural selection, he is surely going very far to save his _a priori_ dogma; and in the case next adduced will have to go further still. In the next place, is it either fair or reasonable to expect that a varietal character of presumably very recent origin should be as strongly inherited--and therefore as constant both in occurrence and symmetry--as a true specific character, say, of a thousand times its age? Even characters of so-called "constant varieties" in a state of nature are usually less constant than specific characters; while, again, as Darwin says, "it is notorious that specific characters are more variable than generic,"--the reason in both cases being, as he proceeds to show, that the less constant characters are characters of more recent origin, and therefore less firmly fixed by heredity[100]. Hence I do not understand how Mr. Wallace can conclude, as he does, "that, admitting that this peculiar appendage is wholly useless and meaningless, the fact would be rather an argument against specific characters being also meaningless, because the latter never have the characteristics [i.e. inconstancy of occurrence, form, and transmission] which this particular variation possesses[101]." Mr. Wallace can scarcely suppose that when specific characters first arise, they present the three-fold kind of constancy to which he here alludes. But, if not, can it be denied that these peculiar appendages appear to be passing through a phase of development which all "specific characters" must have passed through, before they have had time enough to be firmly fixed by heredity[102]? [100] _Origin of Species_, pp. 122-3. [101] _Darwinism_, p. 140.