270 



SEXUAL SELECTION: MAMMALS. 



[I'AKT n. 



vidjc), and of certain antelopes, are furnished with a dew- 

 lap, or great fold of skin on the neck, which is much less 

 developed in the female. 



Now, what must we conclude Avith respect to such 

 sexual differences as these ? No one will pretend that the 





Fig. 66.— Pithecia Satanae, male (from Brehm). 



boards of certain male goats, or the dewlap of the bull, 

 or the crests of hair along the backs of certain male ante- 

 lopes, are of any direct or ordinary use to them. It is 

 possil)le that the immense beard of the male Pithecia, 

 and the large beard of the male Orang, may protect their 

 tliroats wlien fighting ; for the keepers in the Zoological 

 (Jurdens inform me that many monkeys attack each other 

 by the throat : but it is not probable that the beard has 



