Alfred Russel Wallace 



transmitted to that sex alone, and that from some un- 

 known cause such characters apparently appear oftener in 

 the male than in the female. Secondly, characters may be 

 developed and be confined to the male, and long after- 

 wards be transferred to the female. Thirdly, characters 

 may, again, arise in either sex and be transmitted to both 

 sexes, either in an equal or unequal degree. In this latter 

 case I have supposed that the survival of the fittest has 

 come into play with female birds and kept the female dull- 

 coloured. With respect to the absence of spurs in female 

 gallinaceous birds, I presume that they would be in the 

 way during incubation ; at least, I have got the case of a 

 German breed of fowls in which the hens were spurred, 

 and were found to disturb and break their eggs much. 



With respect to the females of deer not having horns, I 

 presume it is to save the loss of organised matter. 



In your note you speak of sexual selection and pro- 

 tection as sufficient to account for the colouring of all 

 animals; but it seems to me doubtful how far this will 

 come into play with some of the lower animals, such as 

 sea anemones, some corals, etc. etc. 



On the other hand, Haeckel has recently well shown that 

 the transparency and absence of colour in the lower oceanic 

 animals, belonging to the most different classes, may be well 

 accounted for on the principle of protection. 



Some time or other I should like much to know where 

 your paper on the nests of birds has appeared, and I shall 

 be extremely anxious to read your paper in the West^ninster 

 Review. 



Your paper on the sexual colouring of birds will, I have 

 no doubt, be very striking. 



Forgive me, if you can, for a touch of illiberality about 

 your paper, and believe me yours very sincerely, 



Ch. Darwin. 

 186 



