S 6 



The Descent of Man. 



Part II. 



and in a third species (C. Stoddcwtii, fig. 34) the whole appen- 

 dage is converted into a horn, which is usually of a white 

 colour, but assumes a purplish tint when the animal is excited. 

 In the adult male of this latter species the horn is half an inch 

 in length, but it is of quite minute size in the female and in the 

 young. These appendages, as Dr. Gunther has remarked to me, 

 may be compared with the combs of gallinaceous birds, and 

 apparently serve as ornaments. 



Fig. 35. Chamajleon bifurcus. Upper figure, male ; lower figure, female. 



In the genus Chamoeleon we come to the acme of difference 

 between the sexes. The upper part of the skull of the male 

 C. bifurcus (fig. 35), an inhabitant of Madagascar, is produced 

 into two great, solid, bony projections, covered with scales like 

 the rest of the head; and of this wonderful modification of 

 structure the female exhibits only a rudiment. Again, in 



