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Show 84 SEXUAL SELEC'l'ION. [CHAP. IV cases, victory will depend not on general vigour, hut on having special weapons, confined to the 1nale sex. A hornless stag, or spurl<?ss co~k would have a poor cha~ce of leaving offspring. Se. '"ual selection bl alwa_ys allowing the victor to breed might surely give 1ndo~1table co~uage, length to the spur, and strength to the WI~g to stnke in the spurred leg, as well as the brutal cock-fighter, who kno,vs well that he can improve his breed by carefnl selection of the best cocks. IIow low in the scale of nature this la'v of battle descends, I know not; male alligators have been described as fighting, bellowing, and ·whirling round, like Indians in a war-dance, for the posses ion of the fmnales ; 1nale salmons have been seen :fio-hting all day long; 1nale stag-beetles often bear wounds fi~1n the hugo 1nandibles of other 1nales. The war is, perhaps, severest between the 1nalos of polygamous anilnals, and these semn oftenest provided 'vith special 'veapons. The 1nales of carnivorous ani1nals are already well arn1ed ; though to thmn and to others, special 1neans of defence 1nay be given through means of sexual selection, as the n1ane to the lion, the shoulder-pad to the boar, and the hooked j a'v to tho 1nale salmon ; for the shield may be as i1nportant for victory, as the sword or spear. .A1nongst birds, the contest is often of a more peaceful character. All those who have attended to the subject, believe that there is tho severest rivalry between the 1nales of many species to attract by singing tho fe1nales. The rock-thrush of Guiana, birds of Paradise, and some others, congregate ; and successive males display their gorgeous plumage and perform strange antics before the fmnales, 'vhich standing by as spectators, at last choose the 1nost attractive partner. Those who have closely attended to birds in confinement well kno'v that they often take individual preferences and dislikes: thus Sir R. Ilm·on has described how one pied peacock was mninently attractive to all his hen birds. It may appear childish to attribute any effect to such apparently weak 1n.eans: I cannot here enter on the details necessary to support this view; but if man can in a short time give elegant carriage and beauty to his bantams, according to CnAP. IV.] NATURAL SELECTION. 85 his standard of beauty, I can see no good reason to doubt that female birds, by . electing, durin~ thousands of generations, the 1nost melodious orb antiful males, according to their standard of beauty, 1night produce a 1narked effect. I strongly suspect that son1e well-known la·ws with re pect to the plu1nage of 1nalo and fen1ale birds, in cOinparison with the plu1nage of the young, can be explained on the view of plu1nage havino- been chiefly modified by sexual selection, acting when if1e birds have co1ne to the breeding age or during the breeding season ; the lnodifications thus produced being inherited at corresponding ages or seasons, either by the 1nales alone, or by the males and females; but I have not space here to enter on this subject. Thus it is, as I believe, that 'vhen the males and females of any animal have the same general habits of life, but differ in structure, colour, or ornament, such dH:J'crences have been n1ainly caused by sexual selection; that is, individual males have had, in successive generations, s01ne sHght advantage over other males, in their weapons, means of defence, or chal'lns; and have transmitted those advantages to their male offspring. Yet, I would not wish to attribute all such sexual differences to this agency : for we see peculiarities arising and bec01ning attached to the 1nale sex in our do1nestic animals (as the wattle in 1nale carriers, horn-like protuberances in the cocks of certain fowls, &c.), which we cannot believe to be cith r useful to the males in battle, or attractive to tho females. We see analogous cases under nature, for instance, the tuft of hair on the breast of the turkey-cock, which can hardly be either useful or ornamental to this bird ;-indeed, had the tuft appeared under domestication, it would have been called a monstrosity. Illustrations of the action Qf .Natural Selection.-In order to make it clear how, as Tbelieve, natural selection acts, I must beo- permission to give one or two imaginary illustrations. Let us take the case of a wolf, which preys on various animals, securing some by craft, some by strength, and some by fleetness ; and let us suppose that |