. The descent of man, and selection in relation to sex. Evolution; Natural selection; Sexual selection in animals; Human beings -- Origin; Sexual dimorphism (Animals). Chap. XII.] REPTILES. 31 nished with a crest, which runs along the back and tail, and can be erected at pleasure; but of this crest the female does not exhibit a trace. In the Indian Copliotis ceylanica, the female possesses a dorsal crest, though much less de- veloped than in the male ; and so it is, as Dr. Gtinther in- forms me, with the females of many Iguanas, Chameleons, and other lizards. In some species, however, the cres
. The descent of man, and selection in relation to sex. Evolution; Natural selection; Sexual selection in animals; Human beings -- Origin; Sexual dimorphism (Animals). Chap. XII.] REPTILES. 31 nished with a crest, which runs along the back and tail, and can be erected at pleasure; but of this crest the female does not exhibit a trace. In the Indian Copliotis ceylanica, the female possesses a dorsal crest, though much less de- veloped than in the male ; and so it is, as Dr. Gtinther in- forms me, with the females of many Iguanas, Chameleons, and other lizards. In some species, however, the crest is equally developed in both sexes, as in the Iguana tubercu- lata. In the genus Sitana, the males alone are furnished with a large throat-pouch (Fig. 33), which can be folded up like a fan, and is colored blue, black, and red; but these splendid colors are exhibited only during the pair- ing-season. The female does not possess even a rudiment of this appendage. In the Anolis cristatellus, according to Mr. Austen, the throat-pouch, which is bright red mar- bled with yellow, is present, though in a rudimental con- dition, in the female. Again, in certain other lizards, both sexes are equally well provided with throat-pouches. Here, as in so many previous cases, we see, with species belonging to the same group, the same character confined to the males, or more largely developed in the males than in the fe- males, or equally developed in both sexes. The little lizards of the genus Draco, Fig. 33.—Sitana minor. Male, with the t • t vj .x i ,i ffular pouch expanded (from Gun- Which glide through the Lr'B'BeptUeB of India'). air on their rib-supported parachutes, and which in the beauty of their colors baffle description, are furnished with skinny appendages to the throat, " like the wattles of gallinaceous ; These be- come erected when the animal is excited. They occur in both sexes, but are best developed in the male when ar-. Please note that these images are
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