Simiadae, their origin and divisions.
Similarity, sexual.
Singing of the Cicadae and Fulgoridae; of tree-frogs; of birds, object of the.
Sirenia, nakedness of.
Sirex juvencus.
Siricidae, difference of the sexes in.
Siskin, pairing with a canary.
Sitana, throat-pouch of the males of.
Size, relative, of the sexes of insects.
Skin, dark colour of, a protection against heat.
Skin, movement of the; nakedness of, in man; colour of the.
Skin and hair, correlation of colour of.
Skull, variation of, in man; cubic contents of, no absolute test of intellect; Neanderthal, capacity of the; causes of modification of the; difference of, in form and capacity, in different races of men; variability of the shape of the; differences of, in the sexes in man; artificial modification of the shape of.
Skunk, odour emitted by the; white tail of, protective.
Slavery, prevalence of; of women.
Slaves, difference between field- and house-slaves.
Sloth, ornaments of male.
Smell, sense of, in man and animals.
Smith, Adam, on the basis of sympathy.
Smith, Sir A., on the recognition of women by male Cynocephali; on revenge by a baboon; on an instance of memory in a baboon; on the retention of their colour by the Dutch in South Africa; on the polygamy of the South African antelopes; on the polygamy of the lion; on the proportion of the sexes in Kobus ellipsiprymnus; on Bucephalus capensis; on South African lizards; on fighting gnus; on the horns of rhinoceroses; on the fighting of lions; on the colours of the Cape Eland; on the colours of the gnu; on Hottentot notions of beauty; disbelief in communistic marriages.
Smith, F., on the Cynipidae and Tenthredinidae; on the relative size of the sexes of Aculeate Hymenoptera; on the difference between the sexes of ants and bees; on the stridulation of Trox sabulosus; on the stridulation of Mononychus pseudacori.
Smynthurus luteus, courtship of.
Snakes, sexual differences of; mental powers of; male, ardency of.
"Snarling muscles."
Snipe, drumming of the; coloration of the.
Snipe, painted, sexes and young of.
Snipe, solitary, assemblies of.
Snipes, arrival of male before the female; pugnacity of male; double moult in.
Snow-goose, whiteness of the.
Sociability, the sense of duty connected with; impulse to, in animals; manifestations of, in man; instinct of, in animals.
Social animals, affection of, for each other; defence of, by the males.
Sociality, probable, of primeval men; influence of, on the development of the intellectual faculties; origin of, in man.
Soldiers, American, measurements of.
Soldiers and sailors, difference in the proportions of.
Solenostoma, bright colours and marsupial sac of the females of.
Song, of male birds appreciated by their females; want of, in brilliant plumaged birds; of birds.
Sorex, odour of.
Sounds, admired alike by man and animals; produced by fishes; produced by male frogs and toads; instrumentally produced by birds.
Spain, decadence of.
Sparassus smaragdulus, difference of colour in the sexes of.
Sparrow, pugnacity of the male; acquisition of the Linnet's song by a; coloration of the; immature plumage of the.
Sparrow, white-crowned, young of the.
Sparrows, house- and tree-.
Sparrows, new mates found by.
Sparrows, sexes and young of; learning to sing.
Spathura Underwoodi.
Spawning of fishes.
Spear, used before dispersion of man.
Species, causes of the advancement of; distinctive characters of; or races of man; sterility and fertility of, when crossed; supposed, of man; gradation of; difficulty of defining; representative, of birds; of birds, comparative differences between the sexes of distinct.
Spectrum femoratum, difference of colour in the sexes of.
Speech, connection between the brain and the faculty of; connection of intonation with music.
Spel, of the black-cock.
Spencer, Herbert, on the influence of food on the size of the jaws; on the dawn of intelligence; on the origin of the belief in spiritual agencies; on the origin of the moral sense; on music.