Surely comment is needless. Have the colour of external organs and integuments nothing to do with the determining of specific distinctions by systematists? Or, may we not rather ask, are there any other "characters" which have had more to do with their delineation of animal species? Therefore, if "the external organs and integuments naturally give rise to a greater variety of colours," for non-utilitarian reasons, than is the case with internal organs and tissues; while even the latter present, for similarly non-utilitarian reasons, such variety and intensity of colours as they do; must it not follow that, on the ground of the "Laws of Growth" alone, Mr. Wallace has conceded the entire case as regards "a large proportional number of specific characters" being non-adaptive--"spontaneous" in their occurrence, and "meaningless" in their persistence? Once more:-- "The enormously lengthened plumes of the bird of paradise and of the peacock, can, however, have no such use [i.e. for purposes of defence], but must be rather injurious than beneficial in the birds' ordinary life. The fact that they have been developed to so great an extent in a few species is an indication of such perfect adaptation to the conditions of existence, such complete success in the battle for life, that there is, in the adult male at all events, a surplus of strength, vitality, and growth-power, which is able to expend itself in this way without injury. That such is the case is shown by the great abundance of most of the species which possess these wonderful superfluities of plumage.... Why, in allied species, the development of accessory plumes has taken different forms, we are unable to say, except that it may be due to that individual variability which has served as a starting-point for so much of what seems to us strange in form, or fantastic in colour, both in the animal and vegetable world[136]." [136] _Darwinism_, pp. 292-3.