COURTSHIP OF THE GREAT CRESTED GREBE. 559 
white bars very distinctly. After 15 or 20 seconds, during which 
I think a little further preening was done, the wings were brought 
back to the normal position. 
12. Postscript. 
Owing to accidental circumstances, it was unfortunately only 
after the completion of the MS. of this paper that I was able to 
read Mr. W. P. Pyeraft’s interesting book on the Courtship of 
Animals (Pyeraft, 713). 
As Lintend to attack the problem of the relations of Mutual 
and Sexual Selection in a more general article, it will be un- 
necessary to discuss bis general conclusions here m detail. Let 
me only say that had I, before writing this paper, read his general 
discussion of female choice and of the modifications required in 
Darwin’s original Sexual Selection theory, much of my own 
theoretical conclusions would have been differently expressed, 
although perhaps not essentially altered. 
Let it be particularly noted, however, that Mr. Pycraft himself 
is careful to point out that Darwin’s main conclusions stand firm. 
As I understand it, the chief modification necessary relates to 
female choice. Display and ornament do not act on the esthetic 
sense of the female, but on her emotional state; they are—using 
the words in no narrow or unpleasant sense—excitants, aphro- 
_ disiaes, serving to raise the female into that state of exaltation 
and emotion when alone she will be ready to pair. This is 
brought out most vividly in the nuptial behaviour of the Newts 
(Pycraft, “13, p. 170). No one, after reading this, can fail to 
understand not only that the pure Darwinian theory needs 
modifying, but also the direction in which it must be modified. 
But the element of choice does, in another form, remain. In 
animals such as Birds, where there is a regular pairing-up season, 
and where, too, the mental processes are already of considerable 
complexity, it is impossible to doubt but that mating may be, and 
in some species is, guided by impulse, unanalysable fancies, indi- 
vidual predilection. There, in a rudimentary state, we find that 
form of “ choice ”—intuitive, unreasoned, but none the less im- 
pervious, and none the less in its results a true choice—which 
reaches its highest stage of development in the intensely-felt 
affinities of man and woman—in that condition known as “ falling 
in love,” where the whole of the subconscious mental activities 
become grafted on to the inherited sexual passions, the whole 
past of the mental organism is summed up in the present, in 
the intensely real act of choice which chooses one from among 
thousands and says, whether in words or no, “that one being, 
and no other, is the being that I desire for my mate.” 
That a choice of this type can exist in birds is shown by the 
subject of this memoir. ‘The individual variations in the court- 
ship-actions provide the raw material for preferential mating, 
and the fact that the birds of a pair often both show some 
