Chap. XVIII. EQUAL TRANSMISSION. 299 



mionus, the domestic cow, two species of antelopes, the 

 musk-deer, the roe, the elk, and reindeer. The roe, 

 for instance, has a red summer and a greyish-white 

 winter coat ; and the latter may perhaps serve as a 

 protection to the animal whilst wandering tJirougli the 

 leafless thickets, sprinkled with snow and hoar-frost. 

 If the above named animals were gradually to extend 

 their range into regions perpetually covered with snow, 

 their pale winter-coats would probably be rendered, 

 through natural selection, whiter and whiter by de- 

 grees, until they became as white as snow. 



Although we must admit that many quadrupeds have 

 received their present tints as a protection, yet with a 

 host of species, the colours are far too conspicuous and 

 too singularly arranged to allow us to suppose that they 

 serve for this purpose. We may take as an illustra- 

 tion certain antelopes: when we see that the square 

 white patch on the throat, the white marl^s on the fet- 

 locks, and the round black spots on the eai-s, are all 

 more distinct in the male of the Portax inda, than in 

 the female ; — when we see that the colours are more 

 vivid, that the narrow white lines on the flank and 

 the broad white bar on the shoulder are more distinct 

 in the male Oreas Derbijanus than in the female ; — 

 when we see a similar difference between the sexes 

 of the curiously-ornamented Tragela]plius scriptus (fig. 

 68), — we may conclude that these colours and various 

 marks have been at least intensified through sexual 

 selection. It is inconceivable that such colours and 

 marks can be of any direct or ordinary service to these 

 animals ; and as they have almost certainly been inten- 

 sified through sexual selection, it is probable that they 

 were originally gained through this same process, and 

 then partially transferred to the females. If this view 

 be admitted, there can be little doubt that the equally 



