[267] Geddes and Thomson, The Evolution of Sex, p. 28.
[268] Darwin, The Descent of Man, ii. pp. 107-109, 252.
[269] Cf. Wallace, Tropical Nature, pp. 196-198, Darwinism, p. 284; Westermarck, Human Marriage, pp. 244, 250.
[270] Wallace, Tropical Nature, pp. 193, 209, 210, 213; Darwinism, pp. 284, 287, 292, 294.
[271] Darwin, The Descent of Man, ii. p. 103.
[272] Cf. Wallace, Darwinism, p. 293; Tropical Nature, p. 199.
[273] Cf. Schneider, Der Thierische Wille, p. 367.
[274] Cf. about the relation between sexual ripening and the development of the vocal organs, Buffon, Hist. nat. des oiseaux, i. pp. 21, 22.
[275] For some suggestive remarks in this direction see Espinas, Des sociétés animales, p. 313; and the anonymous paper on “The Descent of Man” in The Quarterly Review, 1871, vol. cxiii. p. 62.
[276] Westermarck, Human Marriage, pp. 245, 249.