III. 



Note on Sexual Selection. 



TN Mr. Cunningham's review of Mr. Romanes' new work, 

 ■^ "Darwin, and after Darwin,"^ the writer gives an independenc 

 and thoughtful criticism of my views on that subject, and I should 

 like to be permitted to make a few observations in reply thereto. 

 Mr. Cunningham says : — " Mr. Wallace argues as though the 

 superior male, facile princeps, in the competition for a living, could 

 found a line of descendants inheriting his own health and vigour, 

 without female assistance." And again : "A male that excels in the 

 struggle for existence is a complete failure, so far as the species is 

 concerned, unless he can succeed also in finding mates." These 

 .passages seem to me to ^involve suppositions against all probability 

 and all evidence. They imply that the better organised male, in all 

 respects, except in ornament, is rejected by the females in favour of 

 the worse organised in every respect, except in ornament. There are 

 here two improbable assumptions — the first, that the most ornament 

 is usually, or frequently, dissociated from the best general organisa- 

 tion ; and the second, that any such less perfectly organised male would 

 be preferred by the female on account of his sligjitly superior orna- 

 ment. For the difference, it must be always remembered, is slight. 

 Out of a hundred male pheasants or peacocks of the same age, the 

 difference in length of plumes or shade of colour is rarely very con- 

 spicuous or even perceptible, except by close comparison ; and if 

 whatever difference there is were not usually associated with vigour 

 and health, then the two forms of sexual selection — by combat and 

 by display of ornament — would lead to different results; and, as males 

 with ornamental appendages usually do fight for the females, the 

 most ornamented would not, in their case, be the parents of the next 

 generation. 



We are, therefore, forced to conclude that the two qualities — 

 general vigour and ornament — aye not independent of each other, but 

 are developed pari passu, and the problem then becomes, does the 

 female determine her choice by the latter rather than by the former ? 

 I quite agree with Mr. Cunningham when he says: "The sexual 

 desire of the female has a hereditary association with certain sensory 



1 Natural Science, vol. i., p. 546. 



