ABSTRACT
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. Both sexes of many species are beautifully coloured exactly alike; and there is no reason to suppose that such colours are protective. No doubt with the bright green kinds which live in the midst of vegetation, this colour serves to conceal them.
