. The descent of man, and selection in relation to sex. Evolution (Biology); Sexual selection in animals; Sexual dimorphism (Animals); Sex differences; Human beings. Chap. XIV.] GRADATION OF CHARACTERS. 133 progenitors of the peacock c in any degree a Polyplectron. But on continuing my search, I observed that in some of the species the two ocelli stood very near each other ; that in the tail-feathers of P. Hard- wlckii they touched each other; and, finally, that in the tail-coverts of this same spe- cies as well as of P. malaccense (Fig. 55) they were actually confluent. As the central part al
. The descent of man, and selection in relation to sex. Evolution (Biology); Sexual selection in animals; Sexual dimorphism (Animals); Sex differences; Human beings. Chap. XIV.] GRADATION OF CHARACTERS. 133 progenitors of the peacock c in any degree a Polyplectron. But on continuing my search, I observed that in some of the species the two ocelli stood very near each other ; that in the tail-feathers of P. Hard- wlckii they touched each other; and, finally, that in the tail-coverts of this same spe- cies as well as of P. malaccense (Fig. 55) they were actually confluent. As the central part alone is confluent, an indenta- tion is left at both the upper and lower ends; and the sur- rounding colored zones are likewise ; A single ocellus is thus formed on each tail-covert, though still plainly betraying its double origin. These confluent ocelli differ from the single ocelli of the peacock in having an indenta- tion at both ends, instead of at the lower or basal cud alone. The explanation, however, of this difference is not difficult ; in some species of Polyplec- tron the two oval ocelli on the same feather stand parallel to each other; in other species (as in P, chinguis) they con verge tow ard one end ; now the partial confluence of two not have resembled. Fig. 54.—Part of a tail-covert of Poly plcctron cbinquiB, with the- two ocelli of natural 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
Size: 1221px × 2048px
Photo credit: © Paul Fearn / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, booksubjectevolutionbio, booksubjecthumanbeings
