. 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 completely absorbed during the winter; so that their feet then resemble those of the This struct- Fig. 31.—Tritoncristatns (half natural size, from Bell's 'British Reptiles'). Upper figure, male during the hreeding-season ; lower figure, female. ure no doubt aids the male in hi
. 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 completely absorbed during the winter; so that their feet then resemble those of the This struct- Fig. 31.—Tritoncristatns (half natural size, from Bell's 'British Reptiles'). Upper figure, male during the hreeding-season ; lower figure, female. ure no doubt aids the male in his eager search and pursuit of the female. With our common newts (Triton puno 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 :i masculine ornament. In many species the body promts strongly-contrasted though lurid tints; and these become more vivid during the breeding-season. The male, lor instance, of our common little newt (Triton />inift<tt us) is " brownish gray above, passing into yellow beneath, which "Bell, "History of Uritiah Reptiles," '2d edit. is in, pp. I .v. 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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