and Nature of Specific Distinctions. 513 



and the very circumstance that the same characters are more 

 developed in one species than in another, necessarily also 

 occasions a gradation in the particular direction, which may 

 happen to be more or less regular, according as circumstances 

 [adaptive relations) require. That there should be a slight 

 break, for instance, in the series where the fringillidous type 

 is modified into Loxia, is perfectly consistent with the nature 

 of the deviation ; but the true affinities of the crossbills are, 

 nevertheless, equally recognisable, and the same may be said 

 in other cases where the hiatus is much more considerable. 



And here it will not be out of place to say a few words 

 upon the terms perfection, degradation, and the like, as applied 

 to natural productions. Let it be borne in mind, that, although 

 every species is equally and wondrously perfect, even to the 

 most trivial minutiae, in reference to the office for which it 

 was designed, still, if we desire to cite an instance wherein 

 the adaptation, if not more perfect, is, at least, more obviously 

 remarkable and extraordinary than in another, it is to aberrant 

 species, rather than to the central or typical exemplifications 

 of a general plan of structure, that we must direct attention ; 

 inasmuch as the former exhibit those modifications of that 

 plan, those adaptations to a peculiar mode of life, which are 

 the most calculated to excite our wonder and admiration. 

 Such forms as Loxia and Recurvirostra are sufficient illus- 

 trations of the position. There, perhaps, would be no objec- 

 tion to the word degradation, understood strictly in a classical 

 sense ; but, when we consider its popular, its English meaning, 

 in which alone it will be apprehended by an extensive class 

 of readers, no term should be more carefully avoided : the 

 most degraded species absolutely happening to be those which 

 are the most worthy our especial admiration. 



The difficulties of classification arise from the necessary 

 fact (obviously necessary when we consider the adaptive re- 

 lations of species) of there being successive centres of radia- 

 tion ; the different modifications of a leading plan of structure 

 radiating in their turn, and thereby constituting an irregular 

 series of subordinate types, of every degree of value. Thus, 

 the starling type is comprehended in the omnivorous or corvine 

 plan of structure, and, in its turn, comprises others of less 

 importance, upon all of which may be organised an indefinite 

 number of species, diversely modified to suit a variety of 

 localities, and often approximating in external appearance to 

 species framed upon other general types of structure, wherever 

 they are alike modified to perform the same office in the 

 adaptive system : such approximation, however, by no means 

 inducing an additional degree of physiological affinity. 



