. The descent of man, and selection in relation to sex. Evolution; Natural selection; Sexual selection in animals; Human beings -- Origin; Sexual dimorphism (Animals). 320 SEXUAL SELECTION. [Part II. a from the left-hand one, the latter resembling in its sim- pie tapering joints the antenna? of the female. In the male the modified antenna is either swollen in the middle or angu- larly bent, or converted (fig. 3) into an elegant, and sometimes wonderfully complex, prehensile It serves, as I hear from Sir J. Lubbock, to hold the fe- male, and for this same purpose one of the two posterio
. The descent of man, and selection in relation to sex. Evolution; Natural selection; Sexual selection in animals; Human beings -- Origin; Sexual dimorphism (Animals). 320 SEXUAL SELECTION. [Part II. a from the left-hand one, the latter resembling in its sim- pie tapering joints the antenna? of the female. In the male the modified antenna is either swollen in the middle or angu- larly bent, or converted (fig. 3) into an elegant, and sometimes wonderfully complex, prehensile It serves, as I hear from Sir J. Lubbock, to hold the fe- male, and for this same purpose one of the two posterior legs (b) on the same side of the body is converted into a forceps. In an- other family the inferior or pos- terior antennae are " curiously zig- zagged " in the males alone. In the higher crustaceans the anterior legs form a pair of chelae or pincers, and these are gener- ally larger in the male than in the female. In many species the FlG' 3"7fromiLuCbbock))arwinii cnelse on tne opposite sides of the a. Part of right-hand anterior body are of Unequal size, the right- antenna of male, forming a 1 â * â¢â T . n â * prehensile organ. hand one being, as I am informed b. Posterior pair of the thoracic -i -»«- rv o t> n legs of male. by Mr. L>. fepence Bate, generally, though not invariably, the largest.* This inequality is often much greater in the male than in the female. The two chelae also often differ in structure (figs. 4, 5 and 6), the smaller one resembling those of the fe- male. What advantage is gained by their inequality in size 5 See Sir J. Lubbock in 'Annals, and Mag. of Nat. Hist.' vol. xi. 1853, pis. i. and x.; and vol. xii. (1853) pi. vii. See also Lubbock in ' Transact. Ent. Soc.' vol. iv. new series, 1856-1858, p. 8. With respect to the zig- zagged antennae mentioned below, see Fritz Muller, ' Facts and Argu- ments for Darwin,' 1869, p. 40, Please note that these images are extracted from scanned page images that may hav
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Keywords: ., boo, bookcentury1800, bookdecade1870, booksubjectnaturalselection
