288 DARWINISM chap. 



beak towards the female, and chuckles with delight," while he 

 has never seen the more plain coloured thrush demonstrative 

 to the female. The linnet distends his rosy breast, and 

 slightly expands his brown Avings and tail ; Avhile the various 

 gay coloured Australian finches adopt such attitudes and 

 postiu'es as, in every case, to show off their variously coloured 

 plumage to the best advantage.^ 



A Theory of Aninuil Coloration. 



Having rejected Mr. Darwin's theory of female choice as 

 incompetent to account for the brilliant colours and markings 

 of the higher animals, the jDreponderance of these colours and 

 markings in the male sex, and their display during periods 

 of activity or excitement, I may be asked what explanation 

 I have to offer as a preferable substitute. In my Tropical 

 Nature I have already indicated such a theory, which I will 

 now briefly explain, supporting it by some additional facts 

 and arguments, which appear to me to have great weight, and 

 for which I am mainly indebted to a most interesting and 

 suggestive posthumous Avork by Mr. Alfred Tylor.^ 



The fundamental or ground colours of animals are, as has 

 been shown in preceding chapters, very largely protective, 

 and it is not improbalile that the primitive colours of all 

 animals Avere so. During the long course of animal develop- 

 ment other modes of protection than concealment by harmony 

 of colour arose, and thenceforth the normal development of 

 colour due to the complex chemical and structural changes 

 ever going on in the organism, had full play ; and the colours 

 thus produced Avere again and again modified by natural selection 

 for pui'poses of Avarning, recognition, mimicry, or special pro- 

 tection, as has been already fully explained in the preceding 

 chapters. 



)( Mr. Tylor has, hoAvever, called attention to an important 



principle Avhich underlies the various patterns or ornamental 

 markings of animals — namely, that diversified coloration 

 folloAvs the chief lines of structure, and changes at points, such 

 as the joints, Avhere function changes. He says, " If Ave 

 take highly decorated species — that is, animals marked by 



1 Descent of Man, pp. 401, 402. 

 ^ Colaration in Animals and Plants, Loudon, 1886. 



