COLOURS PRODUCED BY COURTSHIP 285 



the aesthetic sense is widely distributed among the 

 higher animals (vertebrates and some of the most 

 specialised invertebrates), and that the colours which 

 certainly appeal to this sense in man, are not without 

 effect in causing gratification to the animals them- 

 selves. Among the other forms of rivalry between the 

 males for the possession of the females, there is rivalry 

 in beauty and its appropriate display ; and the choice 

 of the females being largely determined by their 

 aesthetic preferences, the beauty and agility of the 

 males has been gradually increased. The females 

 may share in the growing adornment, for the qualities 

 of the male will tend to pass over by degrees into the 

 female offspring, although such tendencies will be 

 often checked by the operation of natural selection, 

 as Mr. Wallace has shown us in a most convincing 

 manner. 1 



This explanation of the origin and meaning of 

 sexual colouring is not accepted by Mr. Wallace, 

 Darwin's great compeer in the discovery of the fruit- 

 ful principle of natural selection, and he brings forward 

 many difficulties, and suggests alternative explanations 

 in his recent work on ' Darwinism.' 



It is of course quite impossible to discuss this 

 most interesting and difficult subject in any adequate 

 manner within the limits of the present work. This 

 volume would, however, be incomplete without some 



1 Darwinism, 1st edit. chap. x. pp. 268-300. Further allusions to 

 Mr. Wallace's views on the subject refer to this chapter of his work. 



