450 



INDEX 



sense cells, stimulation of, 188. 



,, organs, 18, 121. 

 sepals, 106. 



series, progressive, 232, 23-1. 

 tiesia crabroniformis, Fig. 175. 

 sex determination in insects, 135, 



Pig. 67. 

 sexes, fundamental distinction 



between, 127. 



sexual characters transferred to 

 asexual generation, 110, 

 111. 



,, differentiation, origin of, 128. 

 sexual phenomena, 84, 85. 

 evolution of, 126, 127. 

 in Bodo, 87, Fig. 38. 

 Coccidium, 88, Fig. 39. 

 Ccelomata, 125. 

 Copromonas, 83, Fig. 37. 

 Eudorina, 91, Fig. 40. 

 ferns, 104, 105, Figs. 51, 52 

 flowering plants, 108, 109, 



Figs. 54, 55. 



Fucus, 100, 101, Fig. 47. 

 Hsematococcus, 33, Fig. 5. 

 Hydra, 116. 

 Obelia, 121. 



Pandorina, 89, Fig. 10. 

 Paramoecium, 93, Fig. 41. 

 Spirogyra, 96, 97, Figs. 43, 44. 

 Volvox, 91, Fig. 11. 

 Zygogonium, 97. 

 sexual reproduction, 33. 



,, selection, Charles Darwin on, 



388. 

 ,, ,, Erasmus Darwin 



on, 373. 



Shand, Alexander, 399. 

 sharks, fossil, 291. 

 sheep. Ancon or otter, 154. 



feet, 241. 



shepherd's purse, 48, Fig. 14. 

 Shirreff, Patrick, 412. 

 shoulder girdle, of mammals, 234, 



Fig. 90. 

 ,, ,, ,, Ornithorhynchus, 



234, Fig. 93. 

 reptiles, 233, 234, 



Fig. 89. 



Sicilian pea, 208. 

 silica, 23, 24. 

 siliceous skeleton, 25. 

 Silurian Epoch, 284. 

 single selection, 412. 

 Sirenia, 301. 



paddles, 236, 244. 

 size, increase of, 309, 405409. 



skeleton (see feet, limbs, paddles 



and wings). 

 ,, of extinct animals, Figs. 



139152. 

 giraffe, Fig. 104. 

 ,, horse and man, Fig. 95. 



kiwi, Fig. 112. 

 Obelia, 119. 

 Protista, 2326, Figs. 



3,4. 



whale, Fig. 101. 

 skulls of dog and thylacine, 251, 



Figs. 107, 108. 

 slime fungi (see Mycetozoa). 

 sloths, 333. 



slow worm (see Anyuisfragilis}. 

 snails, dispersal, 325. 

 snakes, mimicry in, 343. 

 social problems, de Vries on, 414. 

 sodium, in sea water, 287. 

 sole of foot, Buff on on, 368. 

 solitaire, 258, 397. 

 SoUas, W. J., 286, 287, 311. 

 soma and germ cells contrasted (see 



germ cells and somatic cells). 

 somatic and germ nuclei in Para- 



moacium, 98. 



somatogenic characters, supposed 

 non-inheritance, 169, 176 (see also 

 acquired characters), 

 somatogenic variations, 149, 136 



157. 



somatopleure, 124. 

 somites, 266. 

 soul, 11, 19. 

 South America, fauna and flora, 328, 



329, 333. 



Spalacotherium, 302. 

 special creation, 212 214, 222, Fig. 



82. 



Buff on 011, 369. 

 ,, Lamarck on, 375, 



376. 

 species, aggregate, 224. 



Charles Darwin on, 223. 

 ,, definition of, 223. 

 ,, elementary, 224. 

 ,, Lamarck on, 375. 

 ,, modification of, Buffon on, 



366, 367. 



,, nature of, 222224. 

 ,, number of living, 211. 

 ,, origin from mutations, 225. 

 ,, supposed immutability of (see 



immutability of species). 

 ,, transformation of, Lamarck 

 on, 376, 377. 



