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Show 274 THE PRINCIPLES OF PAnT II. or by the spontaneous movements of the stamens ; and with the Algre, &c., by the locomotive power of the antherozooids. With lowly-organised animals permanently affixed to the same spot and having their sexes separate, the male element is invariably brought to the female · and we can see the reason ; for the ova, even if det~ched before being fertilised and not requiring subsequent nourishment or protection, would be, from their larger relative size, less easily transported than the male element. Hence plants 14 and many of the lower animals are, in this respect, analogous. In the case of animals not affixed to the same spot, but enclosed within a shell with no power of protruding any part of their bodies, and in the case of animals having little power of locomotion, the males must trust the fertilising element to the risk of at least a short transit through the waters of the sea. It would, therefore, be a great advantage to such animals, as their organisation became perfected, if the males when ready to emit the fertilising element, were to acquire the habit of approaching the female as closely as possible. The males of various lowly-organised animals having thus aboriginally acquired the habit of approaching and seeking the females, the same habit would naturally be transmitted to their more highly developed male descendants; and in order that they should become efficient seekers, they would have to be endowed with strong passions. The acquirement of such passions would naturally follow from the more eager males leaving a larger number of offspring than the less eager. The great eagerness of the male has thus indirectly 14 Prof. Sachs(' Lehrbuch der Botanik,' 1870, s. 633) in speaking of the male and female reproductive cells, remarks, "verhalt sich die eine "beider Vereinigung activ, ... die andere erscheint bei der Verein" igung passiv." CIIAP. \'III. SEXUAL SELECTION. 275 led to the much more frequent development of secondary sexual characters in the male than in the female. But the development of such characters will have been much aided, if the conclusion at which I arrived after studying domesticated animals, can be trusted, namely, that the male is more liable to vary than the female. I am aware how difficult it is to verify a conclusion of this kind. Some slight evidence, however, can be gained by comparing the two sexes in mankind, as man has been more carefully observed than any other animal. During the Novara Expedition 15 a vast number of measurements of various parts of the body in different races were made, and the men were found in almost every case to present a greater range of variation than the women; but I shall have to recur to this subject in a future chapter. Mr. J. Wood,I6 who has carefullv attended to the variation of the muscles in man, puts in italics the conclusion that "the greatest number of " abnormalities in each subject is found in the males." He had previously remarked that "altogether in 102 " subjects the varieties of redundancy were found to "be half as many again as in females, contrasting "widely with the greater frequency of deficiency in "females before described." Professor Macalister like wise remarks 17 that variations in the muscles "are "probably more common in males than females." Certain muscles which are not normally present in mankind are also more frequently developed in the male than in the female sex, although exceptions to this rule 15 'Reise der Novara: Anthropolog. Theil,' 1867, s. 216-269. The results were calculated by Dr. Weisbach from measurements made by Drs. K. Scherzer and Schwarz. On the greater variability of the males of domesticated animals, see my ' Variation of Animals and Plants under Domestication,' vol. ii. 1868, p. 75. 16 'Proceedings Royal Soc.' vol. xvi. July, 1868, p. 519 and 524. 17 'Proc. Royal Irish Academy,' vol. x. 1868, p. 123. T 2 |
