274 MISCELLANEOUS OBJECTIONS TO THE [Chap. VIL 



continued selection, when it ceases to be of service to a 

 species, generally becomes variable, as we see with rudi- 

 mentary organs; for it will no longer be regulated by 

 this same power of selection. But when, from the na- 

 ture of the organism and of the conditions, modifica- 

 tions have been induced which are unimportant for the 

 welfare of the species, they may be, and apparently 

 often have been, transmitted in nearly the same state to 

 numerous, otherwise modified, descendants. It cannot 

 have been of much importance to the greater number 

 of mammals, birds, or reptiles, whether they were clothed 

 with hair, feathers, or scales; yet hair has been trans- 

 mitted to almost all mammals, feathers to all birds, and 

 scales to all true reptiles. A structure, whatever it may 

 be, which is common to many allied forms, is ranked by 

 us as of high systematic importance, and consequently ia 

 often assumed to be of high vital importance to the 

 species. Thus, as I am inclined to believe, morpho- 

 logical differences, which we consider as important — 

 such as the arrangement of the leaves, the divisions of 

 the flower or of the ovarium, the position of the ovules, 

 &c. — first appeared in many cases as fluctuating varia- 

 tions, which sooner or later became constant through 

 the nature of the organism and of the surrounding con- 

 ditions, as well as through the intercrossing of distinct 

 individuals, but not through natural selection; for as 

 these morphological characters do not affect the welfare 

 of the species, any slight deviations in them could not 

 have been governed or accumulated through this latter 

 agency. It is a strange result which we thus arrive at, 

 namely that characters of slight vital importance to the 

 species, are the most important to the systematist; but, 

 as we shall hereafter see when we treat of the genetic 



