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676

* Semnopithecus nasica, nose of, 150.
 * nemœus, colouring of, 551.
 * rubicundus, ornamental hair on the head of, 548.
 * Senses, inferiority of Europeans to savages in the, 33.
 * Sentinels, among animals, 100, 107.
 * Serpents, instinctively dreaded by apes and monkeys, 67, 71.
 * Serranus, hermaphroditism in, 161.
 * Sex, inheritance limited by, 230.
 * Sexes, relative proportions of, in man, 242, 558; probable relation of the, in primeval man, 591.
 * Sexual characters, secondary, 207; relations of polygamy to, 217; transmitted through both sexes, 226; gradation of, in birds, 430.
 * and natural selection, contrasted, 226.
 * characters, effects of the loss of 231; limitation of, 231.
 * differences in man, 8.
 * selection, explanation of, 209, 213, 220; influence of, on the colouring of Lepidoptera, 319; objections to, 495; action of, in mankind, 595.
 * similarity, 255.
 * Shaler, Prof., sizes of sexes in whales, 516.
 * Sharks, prehensile organs of male, 331.
 * Sharpe, Dr., Europeans in the tropics, 195.
 * , R. B., on Tanysiptera sylvia, 451; on Ceryle, 457; on the young male of Dacelo Gaudichaudi, 467.
 * Shaw, Mr., on the pugnacity of the male salmon, 332.
 * , J., on the decorations of birds, 382.
 * Sheep, danger-signals of, 100; sexual differences in the horns of, 230; horns of, 235, 505; domestic, sexual differences of, late developed, 237; numerical proportion of the sexes in, 246; inheritance of horns by one sex, 505; effect of castration, 506; mode of fighting of, 508; arched foreheads of some, 532.
 * Merino, loss of horns in females of, 231; horns of, 235.
 * Shells, difference in form of, in male and female Gasteropoda, 262; beautiful colours and shapes of, 264.
 * Shield-drake, pairing with a common duck, 414; New Zealand, sexes and young of, 479.
 * Shooter, J., on the Kaffirs, 579; on the marriage-customs of the Kaffirs, 598.
 * Shrew-mice, odour of, 528.
 * Shrike, Drongo, 461.
 * Shrikes, characters of young, 465.
 * Shuckard, W. E., on sexual differences in the wings of Hymenoptera, 277.
 * Shyness of adorned male birds, 403.
 * Siagonium, proportions of the sexes in, 253; dimorphism in males of, 299.
 * Siam, proportion of male and female births in, 245.
 * Siamese, general beardlessness of the, 560; notions of beauty of the, 578; hairy family of, 601.
 * Sidgwick, H., on morality in hypothetical bee community, 99; our actions not entirely directed by pain and pleasure, 120.
 * Siebold, C. T. von, on the proportion of sexes in the Apus, 255; on the auditory apparatus of the stridulant Orthoptera, 283.
 * Sight, inheritance of long and short, 33.
 * Signal-cries of monkeys, 87.
 * Silk-moth, proportion of the sexes in, 250, 251; Aïlanthus, Prof. Canestrini, on the destruction of its larvæ by wasps, 251; difference of size of the male and female cocoons of the, 278; pairing of the, 318.
 * Simiadæ, 152; their origin and divisions, 165.
 * Similarity, sexual, 225.
 * Singing of the Cicadæ and Fulgoridæ, 281; of tree-frogs, 350; of birds, object of the, 368.
 * Sirenia, nakedness of, 56.
 * Sirex juvencus, 292.
 * Siricidæ, difference of the sexes in, 292.
 * Siskin, 394; pairing with a canary, 415.
 * Sitana, throat-pouch of the males of, 355, 358.