INDEX 



451 



specific characters, non-adaptive, 



419422. 

 speech, an acquired character, 156, 



184. 



,, evolution of, 425. 

 Spencer, Herbert, 2, 185, 391. 

 sperinary, 113. 



spermatids, 133, Figs. 65, 66. 

 spermatist (Erasmus Darwin), 371. 

 spermatocytes, 133, Figs. 65, 66. 

 spermatogenesis, 132, 133, 134, 135, 



Figs. 65, 66. 



spermatogonia, 133, Figs. 65, 66. 

 spermatozoa, 85, 139, Fig. 69. 



,, chemo taxis in, 141. 



,, development (see sper- 



matogenesis). 

 of Chara, 141. 

 Coccidium, 88, 141, 



Fig. 39. 



,, Eudorina,91,Fig. 40. 



fern, 104, 141, Fig. 



51. 



Fucus, 100, Fig. 47. 

 Hydra, 116. 

 medusa?, 121. 

 mosses, 141. 

 sponges, 113. 

 Volvox, 91, Fig. 11. 

 spermatozoids, 91. 



sphserechinus, experiments in hybri- 

 dization, 174. 



Sphserella (see Hsematococcus). 

 Sphserozoum, 43, 265, Fig. 12. 

 tSphenodon pundatm, 259, 260, 295, 



320, 331, Figs. 113, 114. 

 spicules (see sponges, spicules). 

 spider crab, 339, 340, Fig. 172. 

 spindle, nuclear, 71. 

 spines, excessive development, 406. 

 spiny anteater (see Echidna), 

 spireme, 71. 



Spirogyra, 9597, 142, Figs. 4244. 

 splanchnopleure, 124. 

 splint bones, 241, 257. 

 sponges, deep sea, 335. 



,, dispersal of fresh water, 



327. 

 ,, gemmules of fresh water, 



327, Fig. 166. 

 ,, germ cells, 113. 

 ,, non - adaptive characters, 



419421. 

 spicules, 26, 232, 419, 420, 



Figs. 88, 187. 



ftponyilla fluriatilis, gemmules. Fig. 

 166. 



spontaneous generation, 214 216, 



219. 



Lamarck on, 374. 

 sporangia of fern, 101, Fig. 48. 



flowering plant, 107, 



Fig. 53. 

 spores, 101. 



,, dispersal, 321. 

 ,, formation, reduction of chro- 

 mosomes, 138. 

 germination, in fern, 103. 

 of Bodo, 87. 

 ,, ,, Coccidium, 89. 

 sporophylls, 107. 

 sporophyte, 101. 



,, of fern, 105, Fig. 48. 



,, ,, flowering plants, 106. 



,, number of chromosomes, 



139. 



sports, 154, 224 (see also mutations). 

 Squalodontidae, 318. 

 Squamata, 295. 



stability of organisms, 155, Fig. 74. 

 stag, antlers, 125. 

 staining reactions, 62, 70. 

 stamens, 106. 

 staminodes, 262. 

 starch, 31. 



star-fish, meristic variation, 149. 

 statoblasts, 327, Fig. 165. 

 stature, variation in human, 152. 

 Staurocephalus murchisoni, Fig. 134. 

 Stebbing, T. R. R, 339. 

 Stegocephalia, 293. 

 Stegosaurus, 299, Fig. 145. 

 Stenobothrus viridulus, spermato- 

 genesis, Fig. 66. 

 Stentor, Fig. 9. 

 Stereognathus, 302. 

 sterility of species when crossed, 



418. 



St. Helena, an oceanic island, 332. 

 stick caterpillars, 337, 338, Fig. 



169. 



Stieda's organ, 260, Figs. 115, 116. 

 stigma, of flower, 107. 

 stimulation of protoplasm and cells, 



188. 

 stimuli, 18. 



,, to development, 145, 146. 

 stimulus, transmission between cells. 



143. 

 ,, to germ cells, 



186190. 

 Stockard, 157. 

 stomata, 64, Fig. 26. 

 storms, dispersal by, 324. 



