VI 
CONTENTS OF VOL. II. 
CHAPTER XIV. 
Birds — continued. 
Choice exerted by the female — Length of courtship — Unpaired 
birds- — Mental qualities and taste for the beautiful — Preference 
or antipathy shewn by the female for particular males — Vari- 
ability of birds — Variations sometimes abrupt — Laws of varia- 
tion — Formation of ocelli — Gradations of character — Case of 
Peacock, Argus pheasant, and Urosticte .. .. Page 99-153 
CHAPTER XV. 
Birds — continued. 
Discussion why the males alone of some species, and both sexes 
of other species, are brightly coloured — On sexually-limited 
inheritance, as applied to various structures and to brightly- 
coloured plumage — Nidification in relation to colour — Loss of 
nuptial plumage during the winter 154-182 
CHAPTER XVI. 
Birds — concluded. 
The immature plumage in relation to the character of the plumage 
in both sexes when adult — Six classes of cases — Sexual differ- 
ences between the males of closely-allied or representative species 
— The female assuming the characters of the male — Plumage of 
the young in relation to the summer and winter plumage of the 
adults — On the increase of beauty in the Birds of the World — 
Protccti ve colouring — Conspicuously-coloured birds — Novelty 
appreciated — Summary of the four chapters on birds 183-238 
