The Descent of Man 7 



stress on the principle of protection, as accounting for the 

 less bright colours of female birds ' {Descent of Man, vol. ii. p. 

 198) ; but now he speaks as if the correctness of his old con- 

 ception of such colours being due to protection was unlikely. 

 *Is it probable/ he asks, 'that the head of the female 

 chaffinch, the crimson on the breast of the female bullfinch, 

 — the green of the female chaffinch, — the crest of the female 

 golden-crested wren, have all been rendered less bright by 

 the slow process of selection for the sake of protection ? / 

 cannot think so ' (vol. ii. p. 176). 



Once more Mr. Darwin shows us (vol. i. p. 125) how he 

 has been over-hasty in attributing the development of certain 

 structures to reversion. He remarks, ' In my Variations of 

 Animals under Domestication (vol. ii. p. 57) I attributed the 

 not very rare cases of supernumerary mammae in women to 

 reversion. But Professor Preyer states that mammce erra- 

 ticce have been known to occur in other situations, even on 

 the back; so that the force of my argument is greatly 

 weakened or perhaps quite destroyed.' 



Finally, we have a postscript at the beginning of the 

 second volume of the Descent of Man which contains an 

 avowal more remarkable than even the passages already 

 cited. He therein declares : — 



' T have fallen into a serious and unfortunate error in relation to 

 the sexual differences of animals, in attempting to explain what 

 seemed to me a singular coincidence in the late period of life at 

 which the necessary variations have arisen in many cases, and the 

 late period at which sexual selection acts. The explanation given is 

 wholly erroneous, as I have discovered by working out an illustration 

 in figures.' 



While willingly paying a just tribute of esteem to the 

 candour which dictated these several admissions, it would 

 be idle to dissemble, and disingenuous not to declare, the 

 amount of distrust with which such repeated over-hasty 



