Cypris, relation of the sexes in.
Cyrtodactylus rubidus.
Cystophora cristata, hood of.
Dacelo, sexual difference of colour in.
Dacelo Gaudichaudi, young male of.
Dal-ripa, a kind of ptarmigan.
Damalis albifrons, peculiar markings of.
Damalis pygarga, peculiar markings of.
Dampness of climate, supposed influence of, on the colour of the skin.
Danaidae.