47o 



Index 



Silver-bill, 410. 



Sirex, 181. 



Siricidas, 181. 



Sitaria, 194. 



Skin, thickening of, 12, 13. 



Skull, 37, 65. 



Skunk, 3. 



Slaves of ants, 141. 



Sleep in plants, 404. 



Sloth, 229. 



Snail, 417. 



Snails, color of, 23. 



Snakes, 14, 193-194, 227. 



Snowy owl, 6. 



Solenobia, 419. 



Soles, 137, 228. 



Sparassus, 178. 



Sparrow, 200 ; English, 112. 



Species, 31, 32, 33 ; adaptation for good of, 



19 ; sharp separation of, 131. 

 Spencer, 240-246, 247, 290. 

 Spermatozoa, 150, 430-433. 

 Sphinx, 186, 388. 



Spiders, 177-178, 179, 406; web, 3. 

 Spirogyra, 420. 

 Spontaneous variability, 134. 

 Spores, 322. 

 Squilla, 177. 

 Squirrels, 210. 

 Stag-beetle, 179. 

 Stags, 203-204, 219. 

 Sterility, 147-152. 

 Strasburger, 395. 

 Stridulating organs, 188, 189. 

 Struggle for existence, 109, no. 

 Stylonychia, 442. 



Survival of the fittest, 107, 108, 109, 117. 

 Sutton, 432. 

 Swallow, 115. 

 Sweating, 12. 



Tadpole, 321, 428. 



Tail, *. 



Tanager, 6. 



Tapeworm, 353 ; number of eggs, no. 



Taraxacum, 305. 



Tear-sacs, 206. 



Teeth, bird's, 67, 68. 



Telegony, 95, 234, 237, 238, 239. 



Tenthredinidas, 181, 425. 



Termite, number of eggs, no. 



Termitidse, 350. 



Thrush, 115. 



Tipulae, 188. 



Toad, 7. 



Torpedo, 132. 



Towle, 392. 



Transitional forms, 42. 



Transmutation theory, 31, 34. 



Traquair, 138. 



Treadwell, 72. 



Treat, 424. 



Tree-frogs, 7. 



Trichina, 353. 



Trifolium, 404. 



Triton, 193. 



Turkeys, 314. 



Turnix, 201, 202. 



Turtles, 193. 



Umbelliferas, 135. 

 Uria lacrymans, 124. 

 Utricularia, 10. 



Vanessa, 360. 



Variability, 92, 93, 95, 96, 318-319. 



Variation, 261, 340. 



Variation, fluctuating, 100, 118, 123. 



Variation under domestication, 136. 



Varieties, 106, 107, 148. 



Varigny, De, 303-306, 314-315, 322. 



Venus fly-trap, 9. 



Verbascum, 148, 149. 



Vertebrates, evolution of, 40, 45. 



Vilmorin, 303, 314. 



Vinson, 178. 



Vries, De, 97, 278, 289-298, 340. 



Vulpine, 209. 



Wallace, 7, 162, 186, 202, 221, 249. 



Walrus, 203. 



Walsh, 181. 



Walther, 59. 



Wasp, 3, 5, 408, 409. 



Waterton, 198. 



Web, spider's, 3, 4. 



Weir, 171. 



Weismann, 154-166, 441, 448-450. 



Westwood, 188. 



Whale, 227, 301. 



Wilson, E. B., 72. 



Wing of bat, 2. 



Wolf, 308, 376. 



Wolves, 412. 



Women, 210. 



Woodpecker, 228. 



Wounds, healing of, 15. 



Yarrell, 138. 

 Yung, 424, 436. 



Zebu cattle, 208. 

 Zeleny, 348. 

 Zoea, 69, 70. 



