Chap. XVIII. DEVELOPMENT OF HAIR. 285 



the rams alone of the above-mentioned xlfrican breed of 

 sheep, is a true secondary sexual character, for it is not 

 developed, as I hear from Mr. Winwood Keade, if the 

 animal be castrated. Although we ought to be ex- 

 tremely cautious, as shewn in my work on ' Variation 

 under Domestication,' in concluding that any character, 

 even with animals kept by semi-civilised' people, has 

 not been subjected to selection by man, and thus aug- 

 mented ; yet in the cases just specified this is im- 

 probable, more especially as the characters are confined 

 to the males, or are more strongly developed in them 

 than in the females. If it were positively known that 

 the African ram with a mane was descended from the 

 same primitive stock with the other breeds of sheep, 

 or the Berbura male-goat with his mane, dewlap, &c., 

 from the same stock with other goats ; and if selec- 

 tion has not been applied to these characters, then 

 they must be due to simple variability, together with 

 sexually-limited inheritance. 



In this case it would appear reasonable to ex- 

 tend the same view to the many analogous characters 

 occurring in animals under a state of nature. Never- 

 theless I cannot persuade myself that this view is 

 applicable in many cases, as in that of the extraordi- 

 nary development of hair on the throat and fore-legs 

 of the male Ammotragus, or of the immense beard of 

 the male Pithecia. With those antelopes in which the 

 male when adult is more strongly-coloured than the 

 female, and with those monkeys ill which this is like- 

 wise the case, and in which the hair on the face is of a 

 different colour from that on the rest of the head, being 

 arranged in the most diversified and elegant manner, 

 it seems probable that the crests and tufts of hair have 



on the practice of selection by semi-civilised people. For the Berbura 

 goat, see Dr. Gray, ' Catalogue,' ibid. p. 157. 



