Otaria nigrescens, difference in the coloration of the sexes of.
Otis bengalensis, love-antics of the male.
Otis tarda, throat-pouch of the male; polygamous.
Ouzel, ring-, colours and nidification of the.
Ouzel, water-, singing in the autumn; colours and nidification of the.
Ovibos moschatus, horns of.
Ovipositor of insects.
Ovis cycloceros, mode of fighting of.
Ovule of man.
Owen, Prof., on the Corpora Wolffiana; on the great toe in man; on the nictitating membrane and semilunar fold; on the development of the posterior molars in different races of man; on the length of the caecum in the Koala; on the coccygeal vertebrae; on rudimentary structures belonging to the reproductive system; on abnormal conditions of the human uterus; on the number of digits in the Ichthyopterygia; on the canine teeth in man; on the walking of the chimpanzee and orang; on the mastoid processes in the higher apes; on the hairiness of elephants in elevated districts; on the caudal vertebrae of monkeys; classification of mammalia; on the hair in monkeys; on the piscine affinities of the Ichthyosaurians; on polygamy and monogamy among the antelopes; on the horns of Antilocapra Americana; on the musky odour of crocodiles during the breeding season; on the scent-glands of snakes; on the Dugong, Cachalot, and Ornithorhynchus; on the antlers of the red deer; on the dentition of the Camelidae; on the horns of the Irish elk; on the voice of the giraffe, porcupine, and stag; on the laryngeal sac of the gorilla and orang; on the odoriferous glands of mammals; on the effects of emasculation on the vocal organs of men; on the voice of Hylobates agilis; on American monogamous monkeys.