286 



SEXUAL SELECTION: MAMMALS. 



[Paet II. 



the throat, the white marks on the fetlocks, and the round 

 black spots on the ears, are all more distinct in the male 

 of the Portax picta, than in the female — when we see that 

 the colors are more vivid, that the narrow white lines on 

 the flank and the broad white bar on the shoulder are 



Fig. 69.— Damalis pygarga, male (from the Knowsley Menagerie). 



• 



more distinct in the male Oreas Derby anus than in the fe- 

 male — when we see a similar difference between the sexes 

 of the curiously ornamented Tragelaphus scriptus (Fig. 

 68) — we may conclude that these colors and various 

 marks have been at least intensified through sexual selec- 

 tion. It is inconceivable that such colors and marks can 

 be of any direct or ordinary service to these animals ; and 



