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. 



