The descent of man, and selection in relation to sex . ved brown spots. Inthe male the basal margin of the anal fin is also a littleproduced and dark-coloured. In the male of an alliedform, the Xipho]j]iorus Hellerii (fig. 29), the inferiormargin of the anal fin is developed into a long filament. ^- Catalogue of Acantli. Fishes in the Biitish Museum, by , 1861, p. 188-151. 1^ CJame Birds of Sweden, &c., 1867, p. 466. ^* With respect to this and the following species I am indebted toDr. Giinther for information : see also his paper on the Fishes ofCentral America, in Transact. Zoolog
The descent of man, and selection in relation to sex . ved brown spots. Inthe male the basal margin of the anal fin is also a littleproduced and dark-coloured. In the male of an alliedform, the Xipho]j]iorus Hellerii (fig. 29), the inferiormargin of the anal fin is developed into a long filament. ^- Catalogue of Acantli. Fishes in the Biitish Museum, by , 1861, p. 188-151. 1^ CJame Birds of Sweden, &c., 1867, p. 466. ^* With respect to this and the following species I am indebted toDr. Giinther for information : see also his paper on the Fishes ofCentral America, in Transact. Zoolog. Soc. vol. vi. 1868, p. 485. 10 SEXUAL SELECTION. Part II. which is striped, as I hear from Dr. Giinther, with brightcolours. This filament does not contain any muscles,and apparently cannot be of any direct use to the in the case of the Callionymus. the males whilstyoung resemble in colour and structure the adultfemales. Sexual differences such as tliese may bestrictly compared with those w^iich are so frequentwith gallinaceous birds.^^.
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Keywords: ., boo, bookcentury1800, bookdecade1870, booksubjectnaturalselection
