Seite - 550 - in The Origin of Species

550 INDEX Scott, J., Mr., on the crossing of 1 arieties of verbascum, 326. Sea-water, how far injurious to seeds, 405, 406. . , , „ not destructive to land-shells, 438, 439;. ^ J • , Sebright, Sir J., on crossed animals, 37- ^ Sedgwick, Prof., on groups of spe- cies suddenly appearing, 354. Seedlings destroyed by insects, 82. Seeds, nutriment in, 91. , winged, 158. , means of dissemination, 203, 2X2, 407, 408. -, power of resisting salt water, 406. , in crops and intestines of birds, 407, 408. , eaten by fish, 408, 430. . in mud, 428. hooked, on islands, 435. Selection of domestic products, 43, -, principle not of recent origin. 48. -, unconscious, 49. -, natural, 93. -, sexual, loi. -, objections to term, 94. - natural, has not induced steril- ity, 312. Sexes, relations of, loi. Sexual characters variable, 166. selection, loi. Sheep, Merino, their selection, 46. , two sub-breeds, unintention- ally produced, 50. -, mountain varieties of, 89. Shells, colours of, 146. , hinges of, 202. , littoral, seldom embedded, 341. , fresh-water, long retain the same forms. 385. -, dispersal of, 428. • , of Madeira, 433. , land, distribution of, 433. , , resisting salt water, 438, 439- Shrew -rnouse,_ 462. Silene, infertility of crosses, 307. Silliman, Prof., on blind rat, 150. Sirenia, their affinities, 378. Sitaris, metamorphosis of, 488. Skulls of young mammals, 208, 475. Slave-making instinct, 275. Smith, Col. Hamilton, on striped horses, 172. • , Mr. Fred., on slave-making ants, 276. -, on neuter ants, 294. Smitt, Dr., on the Polyzoa, 248. Snake with tooth for cutting through egg-shell, 273. Somerville, Lord, on selection of sheep, 46. Sorbus, grafts of, 311. Sorex, 462. Spaniel, King Charles's breed, 49. Specialisation of organs, 135. Species, polymorphic, 60. , dominant, 71. , common, variable, 69. in large genera variable, 71. -, groups of, suddenly appearing, 354, 359- beneath Silurian formations. 360. Species successively appearing, 364. • changing simultaneously throughout the world, 373. Spencer, Lord, on increase in size of cattle, so. , Herbert, Mr., on the first steps in differentiation, 138. on the tendency to an equilib- 316. rium in all forces, 318. Sphex, parasitic, 275. Spiders, development of, 482. Sports in plants, 28. Sprengel, C. C, on crossing, 109. , on ray-florets, 157. Squalodon, 379. Squirrels, gradations in structure, 185. Staffordshire, heath, changes in, 85. Stag-beetles, fighting, loi. Star-fishes, eyes of, 191. , their pedicel!arise, 247. Sterility from changed conditions of life, 27. of hybrids, 300. , laws of, 305. , causes of, 312. from unfavourable conditions, not induced through natural selection, 313. St. Helena, productions of, 43-2- St. Hilaire, Aug., on variability of certain plants, 226, 227. , on classification, 456. St. John, Mr., on habits of cats, 267. Sting of bee, 214. Stocks, aboriginal, of domestic ani- mals, 3=;. Strata, thickness of, in Britain, 339. Stripes on horses, 172. Structure, degrees of utility of, 209. Struggle for existence, 76. Succession, geological, 364. of types in same areas, 388. _ Swallow, one species supplanting another, 90. Swaysland, Mr., on earth adhering to the feet of migratory birds, 409. Swifts, nests of, 289. Swim-bladder, 195. Switzerland, lake-habitations of, 35. System, natural, 452.