. The descent of man, and selection in relation to sex. Evolution; Natural selection; Sexual selection in animals; Human beings -- Origin; Sexual dimorphism (Animals). Chap. XIY.] GRADATION OF CHARACTERS. 133. progenitor of the peacock could not 'have resembled, 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- wickii they, touched each other; and, finally, that in the tail-coverts of this same spe- cies as well as of P. mdlaccense (Fig. 55) they were actually confl
. The descent of man, and selection in relation to sex. Evolution; Natural selection; Sexual selection in animals; Human beings -- Origin; Sexual dimorphism (Animals). Chap. XIY.] GRADATION OF CHARACTERS. 133. progenitor of the peacock could not 'have resembled, 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- wickii they, touched each other; and, finally, that in the tail-coverts of this same spe- cies as well as of P. mdlaccense (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 indented. 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 end 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. chinquis) they con- pIG< 55. _part of a tail-covert of Verge toward one end ; now Polyplectron malac^ccnsc with ° . ' the two ocelli, partially conilu- the partial confluence of tWO ent, of natural size. Fig. 54.—Part of a tail-covert of Poly plectron chinquie, 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 Co.
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