Plecostomus barbatus, peculiar beard of the male.
Plectropterus gambensis, spurred wings of.
Ploceus.
Plovers, wing-spurs of; double moult in.
Plumage, changes of, inheritance of, by fowls; tendency to analogous variation in; display of, by male birds; changes of, in relation to season; immature, of birds; colour of, in relation to protection.
Plumes on the head in birds, difference of, in the sexes.
Pneumora, structure of.
Podica, sexual difference in the colour of the irides.
Poeppig, on the contact of civilised and savage races.
Poison, avoidance of, by animals.