Arachnida.
Arakhan, artificial widening of the forehead by the natives of.
Arboricola, young of.
Archeopteryx.
Arctiidae, coloration of the.
Ardea asha, rufescens, and coerulea, change of colour in.
Ardea coerulea, breeding in immature plumage.
Ardea gularis, change of plumage in.
Ardea herodias, love-gestures of the male.
Ardea ludoviciana, age of mature plumage in; continued growth of crest and plumes in the male of.