INDEX 



501 



Snowdon, elevation in recent times, 

 1.418 



Social instincts, actions as result of, 

 ii. 52 



Social plants, De Candolle on, i. 424 ; 

 in the U.S.A.. i. 431, 432 



Sociology, H. Spencer's i. 351 



Soda, nitrate beds, i. 27 



Soil, in relation to plant distribution, 

 i. 380 



Solanaceae, i. 108 



Solanum, rostratum, Todd on stamens 

 of, ii. 292 



Solenhofen, bird-creature from, i. 234 



Sollas, Prof., director of the Funafuti 

 boring expedition, ii. 199 ; account of 

 the boring operations by, ii, 199 



Sonchus, introduced into New Zealand, 

 i. 102 



Song, importance in animal kingdom, 

 ii. 82 



Sophocles, Prof., on expression of 

 affirmation by Turks, ii. 1 1 1 



Sorby, on metamorphism, ii. 210 



Sound, and music, ii. 51 



Southampton, Brit. Assoc. meeting 

 0846), ii. 175 ; Darwin on gravel 

 deposits at, ii. 165, 169, 237 ; 

 Darwin's visits to, ii. 237, 421 



Spanish chesnut, variation in leaf 

 divergence, ii. 378 



Spanish plants in Ireland, i. 54, 461; 

 in La Plata, i. 452 



Spawn, dispersal of frogs', i. 284 



Spean, terraces in valley of, ii. 149, 171, 

 179, 188-90 



Special ordination, i. 321 



Specialisation, i. 210 



Species, antiquity of plant-, i. 443 ; be- 

 lief in evolution of. i. 304 ; changing 

 into one another, i. 184 ; creation 

 of, i. 173 ; Darwin recognises diffi- 

 culties in and objections to his views 

 on, i. 455 ; definition of, i. 127 ; 

 descriptive work influenced by 

 Darwin's views on, i. 453 5 facts 

 from Hooker bearing on, i. 63 ; 

 food as important factor in keeping 

 up number of, i. 297 ; frequency of, 

 i. 117 ; Asa Gray on, i. 242, 422 ; 

 Hooker on, i. 422 ; intermediate 

 forms absent in close, i. 367, 368 ; 

 little tendency during migration to 

 form new, i. 441 ; modification of, 

 i. 182 ; and monstrosities, i. 242 ; 

 mutability of, i. 42, 43, 96 ; ii. 45 ; 

 Nageli's views on, i. 273 ; origin of, 

 i. 294 (see Origin of Species) ; per- 

 manence of, i. 96, 97 ; Prichard on 

 meaning of term, i. 43-5 5 range of, 



i. 46 ; representative, i. 177 ; separate 

 creation of, i. 163 ; spreading of, 

 i. 449 ; sterility between allied, i. 

 288 ; and sterility, i. 137, 138. 294; 

 time necessary to change, i. 380 ; 

 time of creation of new, i. 244 ; 

 variation of, 41-7, 170, 244; Wallace 

 on origin of, i. 384 ; Walsh on modi- 

 fication of, i. 250 ; Weismann on, 

 i. 311 ; ii. 95> 96 J Gaudry on affilia- 

 tion of, ii. 236 ; Hackel on change 

 of, ii. 346 ; isolation of, ii. 95 ; value 

 of careful discrimination of, ii. 252 



Species not transrmitable, Bree's book 

 on, i. 174 



Specific character, Falconer on persist- 

 ence of, i. 206 



Speculation, Darwin on, ii. 133 



Spencer, H., Darwin on the advantage 

 of his expression "survival of the 

 fittest," i. 270 ; letter to, i. 351, 352 ; 

 ii. 442 ; on electric organs, i. 307 ; 

 on genesis of nervous system, 

 ii. 424, 425 ; on survival of the 

 fittest, i. 268 ; Romanes on his 

 theory of nerve-genesis, i. 368 ; 

 Wallace's admiration for, i. 301 ; 

 Darwin on his work, ii. 235 ; extract 

 from letter to, ii. 249 ; mentioned, i. 



295. 3oo> 301 ; ii. 48, 5 2 

 Spermacoce^ ii. 272 



Spey, terraces of, ii. 189 



Sphagnum, parasitism of orchids on, 



i. 474 

 Spiders, mental powers of, i. 338 ; 



Moggridge on, i. 337, 338 

 Spirant kes, ii. 265 ; fertilisation of, 



ii. 263 



Spiritualism, Darwin on, ii. 443 

 Spitsbergen, Lamont's book on, i. 179 ; 



reindeer of, i. 144 

 Sponges, Clark on classification of, 



i. 335 ; HackePs work on, i. 335 ; 



F. Miiller on, i. 264 ; ii. 346 

 Spontaneous generation, i. 321 ; Dar- 

 win's disbelief in, i. [273 ; Huxley's 



disbelief in, i. 329 

 Sports, i. 213, 275, 276 

 Sprengel, C. C., i. 446 ; ii. 254 ; on 



Passion-flowers, ii. 380 

 Stag-beetle, forms of, ii, 90 

 Stahl, Prof., on Desmodium, ii. 396 ; 



on transpiration, ii. 410 

 Stainton, ii. 67 

 Stanhope, Lord, i. 96 

 Stanhopea, fertilisation of, ii. 335-7, 347 

 Slapelia, fertilisation of, ii. 304 

 Starling, paired three times in one 



day, ii. 74 

 State-entomologist, appointment of in 



