Page:The Zoologist, 4th series, vol 5 (1901).djvu/450

422 channels which bring it to those parts of the body which are most in use in courtship, or chiefly subjected to nuptial energy. Hence may result many nuptial weapons or ornaments. Under such an argument we at once understand how it is that in some animals the sexual characters are permanent, in others transitory. Inasmuch as they follow the growth of the genital organs, where this growth is periodical so are they periodical, and, where the genital organs are influential throughout life, the characters are permanent, waxing and waning, however, like the Stag's horns, with their progress from youth through maturity to senescence. What is inherited, then, may well be not the secondary sexual characters themselves, but the influence of the genitalia, the tendency to the disruption of spare material and its deposition in particular regions, a process which certainly appears to become fixed after numerous generations.

Such is a view of sexual dimorphism and the seasonal assumption of nuptial weapons or ornaments, which I venture to put forward in all humility. Two advantages may be claimed for it—(1) it is based on a physiological standpoint, and starts on firmer and deeper ground than the older theories; (2) it includes in its scope not only persistent sexual dimorphism, but seasonal exhibitions of sexuality.