. The descent of man, and selection in relation to sex. Evolution (Biology); Sexual selection in animals; Sexual dimorphism (Animals); Sex differences; Human beings. Chap. XII.] AMPHIBIANS. 23 season; and at this season in the male Triton palmipes the hind-feet are provided with a swimming web, which is almost comiiletely absorbed during the winter; so that their feet then resemble those of the female.'* This struct-. FiG. 31.—Triton cristatiis (half natural eize, from Bell's 'British Eeptiles'). Upper figure, male during the breeding-season ; lower figure, female. ure no doubt aids the male i
. The descent of man, and selection in relation to sex. Evolution (Biology); Sexual selection in animals; Sexual dimorphism (Animals); Sex differences; Human beings. Chap. XII.] AMPHIBIANS. 23 season; and at this season in the male Triton palmipes the hind-feet are provided with a swimming web, which is almost comiiletely absorbed during the winter; so that their feet then resemble those of the female.'* This struct-. FiG. 31.—Triton cristatiis (half natural eize, from Bell's 'British Eeptiles'). Upper figure, male during the breeding-season ; lower figure, female. ure no doubt aids the male in his eager search and pursuit of the female. With our common newts {Triton lyunc- tatus and cristatus) a deep, much indented crest is devel- oped along the back and tail of the male during the breed- ing-season, being absorbed during the winter. It is not furnished, as Mr. St. George Mivart informs me, with muscles, and therefore cannot be used for locomotion. As during the season of courtship it becomes edged with bright colors, it serves, there can hardly be a doubt, as a masculine ornament. In many species the body presents strongly-contrasted though lurid tints ; and these become more vivid during the breeding-season. The male, for instance, of our common little newt {Triton x>unctatus) is " brownish gray above, passing into yellow beneath, which 33 Bell, "History of British Reptiles," 2d edit. 1849, pp. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Darwin, Charles, 1809-1882. New York, D. Appleton and company
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