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with a sick cat, 103; sympathy of, with his master, 103; their possession of conscience, 103; possible use of the hair on the fore-legs of the, 151; races of the, 176; numerical proportion of male and female births in, 246; sexual affection between individuals of, 524; howling at certain notes, 569; rolling in carrion, 530.
 * Dolichocephalic structure, possible cause of, 56.
 * Dolphins, nakedness of, 56.
 * Domestic animals, races of, 176; change of breeds of, 596.
 * Domestication, influence of, in removing the sterility of hybrids, 172
 * D'Orbigny, A., on the influence of dampness and dryness on the colour of the skin, 193; on the Yuracaras, 582.
 * Dotterel, 477.
 * Doubleday, E., on sexual differences in the wings of butterflies, 277.
 * , H. on the proportion of the sexes in the smaller moths, 251; males of Lasiocampa quercus and on the attraction of the Saturnia carpini by the female 252; on the proportion of the sexes in the Lepidoptera, 252; on the ticking of Anobium tesselatum, 306; on the structure of Ageronia feronia, 307; on white butterflies alighting upon paper, 317.
 * Douglas, J. W., on the sexual differences of the Hemiptera, 281; on the colours of British Homoptera, 282.
 * Down, of birds, 390.
 * Draco, gular appendages of, 355.
 * Dragonet, Gemmeons, 336.
 * Dragon-flies, caudal appendages of male, 276; relative size of the sexes of, 279; difference in the sexes of, 290; want of pugnacity by the male, 291.
 * Drake, breeding plumage of the, 393.
 * Dreams, 74; a possible source of the belief in spiritual agencies, 94.
 * Drill, sexual difference of colour in the, 538.
 * Dromœus, irroratus, 478.
 * Dromolœa, Saharan species of, 456.
 * Drongo shrike, 461.
 * Drongos, racket-shaped feathers in the tails of, 384, 392.
 * Dryness, of climate, supposed influence of, on the colour of the skin, 193.
 * Dryopithecus, 155.
 * Duck, harlequin, age of mature plumage in the, 483; breeding in immature plumage 484.
 * , long-tailed, preference of male, for certain females, 420.
 * , pintail, pairing with a wigeon, 414.
 * , voice of the, 374; pairing with a shield-drake, 414; immature plumage of the, 466.
 * , wild, sexual differences in the 219; speculum and male characters of, 236; pairing with a pintail drake, 415.
 * Ducks, wild, becoming polygamous under partial domestication, 219; dogs and cats recognised by, 412.
 * Dufossé, Dr., sounds produced by fish, 347.
 * Dugong, nakedness of, 56; tusks of, 502.
 * Dujardin, on the relative size of the cerebral ganglia in insects, 54.
 * Duncan, Dr., on the fertility of early marriages, 138; comparative health of married and single, 140.
 * Dupont, M., on the occurrence of the supra-condyloid foramen in the humerus of man, 22.
 * Durand, J. P., on causes of variation, 30.
 * Dureau de la Malle, on the songs of birds, 86; on the acquisition of an air by blackbirds, 370.
 * Dutch, retention of their colour by the, in South Africa, 193.
 * Duty, sense of, 97.
 * Duvaucel, female Hylobates washing her young, 70.
 * Dyaks, pride of, in mere homicide, 117.
 * Dynastes, large size of males of, 279.
 * Dynastini, stridulation of, 303.
 * Dytiscus, dimorphism of females of, 276; grooved elytra of the female, 276.


 * Eagle, young Cercopithecus rescued from, by the troop, 101.
 * , white-headed, breeding in immature plumage, 484.