INDEX 



451 



specific characters, non -adaptive, 



419422. 

 speech, an acquired character, 156, 



184. 



evolution of, 425. 

 Spencer, Herbert, 2, 185, 391. 

 spermary, 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. 



,, chemotaxis 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. 

 ,, medusae, 121. 



,, ,, mosses, 141. 



sponges, 113. 

 Yolvox, 91, Fig. 11. 

 spermatozoids, 91. 



sphserechinus, experiments in hybri- 

 dization, 174. 



Sphaerella (see Hsematococcus). 

 Sphserozoum, 43, 265, Fig. 12. 

 Sphenodon punctatus, 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. 



Sponf/iUa fluviatilis, gemmules, Fig. 

 16(3. 



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). 

 Squalodontidse, 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. E. E., 339. 

 Stegocephalia, 293. 

 Stegosaurus, 299, Fig. 145. 

 Stendbothrus viridultis, 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. 



