Archive image from page 45 of The descent of man, and. The descent of man, and selection in relation to sex descentofmansel02darw Year: 1871 33 SEXUAL SELECTION. [Part II. rived at maturity, at whicli age the middle appendage is Bometimes twice as long as the liead. ISIost of the species likewise have a low crest running along the neck ; and this is much more developed in the fuli-grown males than in the females or young male?.' There are other and much more remarkable differences between the sexes of certain lizai'd;. The male of Cerato- j)l(ora aspera bears on the extremity of his snout an
Archive image from page 45 of The descent of man, and. The descent of man, and selection in relation to sex descentofmansel02darw Year: 1871 33 SEXUAL SELECTION. [Part II. rived at maturity, at whicli age the middle appendage is Bometimes twice as long as the liead. ISIost of the species likewise have a low crest running along the neck ; and this is much more developed in the fuli-grown males than in the females or young male?.' There are other and much more remarkable differences between the sexes of certain lizai'd;. The male of Cerato- j)l(ora aspera bears on the extremity of his snout an appendage half as long as the head. It is cylindrical, covered with scales, flexible, and apparently capable of erection : in the female it is quite rudimental. In a second species of the same genus a terminal scale forms a minute horn on the summit of the flexible appendage ; and in a third species (C. Stoddartif, Fig. 34), the whole api)cnd- age is converted into a horn, which is usually of a white color, but assumes apur])lish tint when the animal is excited. In the adult male of this latter species the horn is half an inch in length, but is of quite minute size in the female and in the young. These appendages, as Dr. Gunther has remarked to me, may be com- pared with the combs of galli- naceous birds, and apparently serve as ornaments. In the genus Chamaleon we come to the climax of dil- ference between the sexes. The v.]i])vt ]iart of the skull of the male C. hifurcus (Fig. 35), an inhabitant of ]Mada- '« All these statements and quotations, in regard to Cophotis, Fitana, and Draco, as well as the followinfi facts in regard to Ceratophora, arc taken from Dr. Gunther's magnificent work on the 'Rcitiles of British India,' Ray Soc. 1864, pp. 122, 130, 135. Fig. 34.—Ccrntophora Stoddartii. Upper figure, male ; lower figure, female.
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