416 THE ZOOLOGIST. 



with maturity in the same manner as that of the male. In the 

 female, however, the colours are, as a rule, duller, and pro- 

 portionately as they are duller, the variations at different stages 

 of maturity are less striking ; in addition to this the plumage is 

 not developed to such an extent, and consequently the form of 

 the bird is less perfect. These facts appear to support my 

 theory. The tendency to develop is there, but, inasmuch as the 

 males court the females, and not the females the males, the 

 rivalry, which on this account exists amongst the males, is un- 

 necessary among the females ; consequently the power, which 

 acts as a stimulant to further development of the plumage of the 

 male, is absent in the case of the female. 



Mr. Darwin, in his ' Descent of Man,' mentions various cases 

 in which the females are brighter than the males, and concludes 

 that in these cases the order is changed, and that instead of the 

 females selecting the males, the males select the females. In so 

 far as it is due to the selection of one sex by the other being 

 reversed, I agree with him ; but, as I have previously pointed 

 out, I differ from him in the manner in which sexual selection 

 works. 



It will be seen, then, that my suggested explanation of the dis- 

 play and selection differs very materially from others; more espe- 

 cially in this fact, that it is not based on direct advantages gained 

 by the offspring of the most successful males, but on the natural 

 development of inherited laws of growth ; and, in addition, it re- 

 gards the action of sexual selection, together with this tendency to 

 develop with age, solely as a means for the development of beauty. 

 In contemplating animated nature we see a development of beauty 

 so marvellous that we can only conclude that such a development 

 must have been equally as important in the history of the world 

 as the development of the fittest in other respects. 



We see in man the aesthetic sense developed to the highest 

 degree, and if we regard that higher idea of creation, which the 

 word Evolution embraces, as applicable to man, then we must 

 look upon this sense as having been dependent on a very modest 

 origin. To deny, therefore, to the lower animals a sense in pro- 

 portion to their development seems to me inconsistent with the 

 whole theory of evolution. The origin of this sense, and of 

 beauty, remains — despite the lengths to which the Weismann 



