Permanence and Evolution. 141 



instance, as the common to the green-necked 

 peacock, they are transmitted to males only 

 without our being able to assign any reason for 

 the difference. Birds, for instance, are much 

 more beautifully coloured and more sexually 

 different than mammals ; have female mammals 

 less taste or power of choice than female birds ? 



But the great objection to sexual selection is 

 total want of evidence for this supposed prefer- 

 ence of female birds for abnormally coloured 

 males. This evidence is attempted to be sup- 

 plied by various anecdotes, which show certainly 

 that female animals often exercise choice, but do 

 not at all show that their choice is regulated by 

 any principles corresponding to what we call 

 aesthetic. Nor does it well agree with what we 

 know of the psychology of brutes to suppose 

 that it is. I can see no reason to think that 

 modifications in the colour of animals con- 

 siderable enough to be noticed would be agree- 

 able to the females, but rather L the reverse. 



