INDEX 



ls7 



Silva, car mm, 167. 



Skate, egg case of Ix'irn door (illu.s.), 



339. 

 Slime mold (illus.), 32. 

 Snails, distribution of land, of 



Hawaii, 123. 

 Solenop.fis fuga, nest of (illus.), 392. 

 Species, changing with space and 



time, IM; estimate of duration 



of, 302; number of, 14; onto- 

 genetic, 114. 

 Species-forming, 117; by saltations, 



156; various theories of, 108. 

 Spencer, Herbert, 5, 196, 197, 198; 



definition of evolut ion, 5; theory 



of protoplasmic structure, 2.')(). 

 Spermatogenesis of ascaris (illus.), 



264. 

 Spermatozoa (illus.), 218. 

 Spcrmatozoan, development of 



(illus.), 266. 

 Spermatozoid, 261. 

 Spha'rechimis Echinus, hybrid lar\'a 



of (illus.), 277; hybrid pluteus 



of (illus.), 280. 

 Sphoorechinus granulans, heating 



larva of (illus.), 279; lithium 



gastrula of (illus.), 279; lithium 



larva of (illus.), 278; normal 



larva of (illus.), 275. 

 Sphenodon, pineal eye of (illus.), 



175. 

 Spider, nest of trap door (illus.), 



346. 

 Sponge, simple (ilhis.), 36. 

 Sports, 186; examples of race formed 



from, 161; species arising from, 



107. 

 Sporulation, reproduction by, 215. 

 Squid (illus.), 40. 

 Stamens of willows, variation in 



(illus.), 160. 

 Stanford, Leland, 103. 

 Starfish, regeneration of (illus.), 



283; walking (illus.), 23. 

 Starks, E. C, 303. 

 Stentor coer ulcus (illus.), 282; re- 



acting to light (illus.), 4:iO; 



reproducing by Jiiision (illu.s.), 



215. 

 Sticklebacks (illus.), 209; onto- 



gonetic variations in, 207. 

 Sting-ray (illu.s.), 333. 

 Structures, convcrgf'nce of, 204; 



l)arall<'lisms in, 204, 

 Struguh' for existence, 57, 60. 

 Strrithio rnmrlu.s (illus.), 45. 

 Sunfi.sh, long-eannj Hllu.s.), 17. 

 Sur\'ival of the fittest, 62. 

 Swift, common (illus.), IS. 

 Swordfi.sh, development of (illus.), 



239. 

 Symbiosis, 373; of {jjarits and 



animals, 376. 

 Si/ngatnus trdchnlia (illus.), 223. 

 Systema Xatunc, 14. 



Tamixi solium (illus.), 355. 



Tail of n)an, hology of, 179. 



Tailor bird, nest of (illus.;, 444. 



Tapeworm (illus.), 355. 



Tarsiil segments, variation in, ccK-k- 

 roach (illus.), 149. 



Taxis, 282. 



Taylor, Hayard, 163. 



Teeth of man and orang-utan corn- 

 pared (illus.), 454. 



Telegony, Kit). 



Telopha.se defined. 2.56. 



Temperature in relation to animal 

 life, 38. 



Termitophily, 372. 



Termites, castes of (illus. \ 395; 

 conununal life of, 394. 



Terrifying appearances. 418. 



Thnlrssn (illu.s.). 'MW ; (illus. 1. :MV2. 



Theory, transmutation, of l>;imnrrk, 

 lil. 



Timothy, heads of, improvetl by 

 selection (illus.), 91. 



Toad (illus.). 344; honntl, pineal 

 eye of (illu.**.), 176; metamor- 

 phosis of (illus.), 237. 



Tobacco worm (illus.), 418, 



