. The descent of man, and selection in relation to sex. Evolution; Natural selection; Heredity; Human beings; Sexual selection in animals; Sexual dimorphism (Animals); Sex differences. BIRDS 543 richly coWed than the males/'* With all other birds in which the trachea differs in structure in the two sexes it is more developed and complex in the male than in the female; but in the Rhynchcea australis it is simple in the male, while in the female it makes four distinct convoln-. ^==^ : Fig. 62. Rliynchaea capensis (from Brehm). .tions before entering the lungs, f The female, therefore, of this sp
. The descent of man, and selection in relation to sex. Evolution; Natural selection; Heredity; Human beings; Sexual selection in animals; Sexual dimorphism (Animals); Sex differences. BIRDS 543 richly coWed than the males/'* With all other birds in which the trachea differs in structure in the two sexes it is more developed and complex in the male than in the female; but in the Rhynchcea australis it is simple in the male, while in the female it makes four distinct convoln-. ^==^ : Fig. 62. Rliynchaea capensis (from Brehm). .tions before entering the lungs, f The female, therefore, of this species has acquired an eminently masculine char- acter. Mr. BIyth ascertained, by examining many speci- mens, that the trachea is not convoluted in either sex of R, hengalensisy which species resembles R. australis so closely that it can hardly be distinguished except by its shorter toes. This fact is another striking instance of the * Jerdon, ** Birds of India," vol. iii, p. 677. t Gould's ** Hand-book to tli© BU^as of Austmti^" vol. H, p. « 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 : A. L. Burt
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