character of insects--Birds and insects compared.


CHAPTER XII.

Secondary Sexual Characters of Fishes, Amphibians, and Reptiles.

Fishes: Courtship and battles of the males--Larger size of the females--
Males, bright colours and ornamental appendages; other strange characters--
Colours and appendages acquired by the males during the breeding-season
alone--Fishes with both sexes brilliantly coloured--Protective colours--The
less conspicuous colours of the female cannot be accounted for on the
principle of protection--Male fishes building nests, and taking charge of
the ova and young. AMPHIBIANS: Differences in structure and colour
between the sexes--Vocal organs. REPTILES: Chelonians--Crocodiles--
Snakes, colours in some cases protective--Lizards, battles of--Ornamental
appendages--Strange differences in structure between the sexes--Colours--
Sexual differences almost as great as with birds.


CHAPTER XIII.

Secondary Sexual Characters of Birds.

Sexual differences--Law of battle--Special weapons--Vocal organs--
Instrumental music--Love-antics and dances--Decorations, permanent and
seasonal--Double and single annual moults--Display of ornaments by the
males.