45Q Darwin, and after Darwin. 



so essentially important for his theory he does not even 

 attempt to show. Lastly, and quite apart from these remarkable 

 oversights, even if Mr. Tylor's hypothesis were as reasonable and 

 well-sustained as it is fanciful and inadequate, still it could not 

 apply to sexual colouration : it could apply only to colouration 

 as affected by physiological functions common to both sexes, 

 Yet it is in order to furnish a " preferable substitute " for Mr. 

 Darwin's theory of sexual colouration, that Mr. Wallace adduces 

 the hypothesis in question as one of " great weight " ! In this 

 matter, therefore, I entirely agree with Poulton and Lloyd 

 Morgan. 



