Rodents, blind, 137.
Rudimentary organs, 450.
Rudiments important for classification, 416.
S.
Sageret on grafts, 262.
Salmons, males fighting, and hooked jaws of, 88.
Salt-water, how far injurious to seeds, 358.
Saurophagus sulphuratus, 183.
Schiödte on blind insects, 138.
Schlegel on snakes, 144.
Sea-water, how far injurious to seeds, 358.
Sebright, Sir J., on crossed animals, 20.
, on selection of pigeons, 31.
Sedgwick, Prof., on groups of species suddenly appearing, 302.
Seedlings destroyed by insects, 67.
Seeds, nutriment in, 77.
, winged, 146.
, power of resisting salt-water, 358.
in crops and intestines of birds, 361.
eaten by fish, 362, 387.
in mud, 386.
, hooked, on islands, 392.
Selection of domestic products, 29.
, principle not of recent origin, 33.
, unconscious, 34.
, natural, 80.
, sexual, 87.
, natural, circumstances favourable to, 101.
Sexes, relations of, 87.
Sexual characters variable, 156.
selection, 87.
Sheep, Merino, their selection, 31.
, two sub-breeds unintentionally produced, 36.
, mountain, varieties of, 76.
Shells, colours of, 132.
, littoral, seldom embedded, 288.
, fresh-water, dispersal of, 385.
of Madeira, 391.
, land, distribution of, 397.
Silene, fertility of crosses, 257.
Silliman, Prof., on blind rat, 137.
Skulls of young mammals, 197, 437.
Slave-making instinct, 219.
Smith, Col. Hamilton, on striped horses, 164.
, Mr. Fred., on slave-making ants, 219.
, on neuter ants, 239.
, Mr., of Jordan Hill, on the degradation of coast-rocks, 283.
Snap-dragon, 161.
Somerville, Lord, on selection of sheep, 31.
Sorbus, grafts of, 262.
Spaniel, King Charles’s breed, 35.
Species, polymorphic, 46.
, common, variable, 53.
in large genera variable, 54.
, groups of, suddenly appearing, 302, 306.
beneath Silurian formations, 306.
successively appearing, 312.
changing simultaneously throughout the world, 323.
Spencer, Lord, on increase in size of cattle, 35.
Sphex, parasitic, 218.
Spiders, development of, 442.
Spitz-dog crossed with fox, 268.
Sports in plants, 9.
Sprengel, C. C., on crossing, 98.
, on ray-florets, 145.
Squirrels, gradations in structure, 180.
Staffordshire, heath, changes in, 72.
Stag-beetles, fighting, 88.
Sterility from changed conditions of life, 9.
of hybrids, 246.
, laws of, 254.
, causes of, 263.
from unfavorable conditions, 256.
of certain varieties, 269.
St. Helena, productions of, 389.
St. Hilaire, Aug., on classification, 418.
St. John, Mr., on habits of cats, 91.
Sting of bee, 202.
Stocks, aboriginal, of domestic animals, 18.
Strata, thickness of, in Britain, 284.
