Rudolphi, on the want of connexion between climate and the colour of the skin.
Ruff, supposed to be polygamous; proportion of the sexes in the; pugnacity of the; double moult in; duration of dances of; attraction of the, to bright objects.
Ruminants, male, disappearance of canine teeth in; generally polygamous; suborbital pits of; sexual differences of colour in.
Rupicola crocea, display of plumage by the male.
Ruppell, on canine teeth in deer and antelopes.
Russia, numerical proportion of male and female births in.
Ruticilla.
Rutimeyer, Prof., on the physiognomy of the apes; on tusks of miocene boar; on the sexual differences of monkeys.
Rutlandshire, numerical proportion of male and female births in.
Sachs, Prof., on the behaviour of the male and female elements in fertilisation.