SQUIRRELS. 



INDEX. 



TUMBLER. 



337 



Squirrels, gradations in structure, i. 



216. 

 Staffordshire, heath, changes in, i. 



87. 

 Stag-beetles, fighting, i. 108. 

 Star-fishes, eyes of, i. 225. 



, their pedieellarise, i. 299. 



Sterility from changed conditions of 



life, i. 10. 



of hybrids, ii. 3. 



, laws of, ii. 11. 



, causes of, ii. 20. 



, from unfavourable conditions, 



ii. 26. 

 not induced through natural 



selection, ii. 21. 

 St. Helena, productions of, ii. 178. 

 St. Hilaire, Aug., on variability of 



certain plants, i. 272. 



, on classification, ii. 209. 



St. John, Mr., on habits of cats, i. 



325. 

 Sting of bee, i. 256. 

 Stocks, aboriginal, of domestic ani- 



mals, i. 22. 

 Strata, thickness of, in Britain, ii. 



55. 

 Stripes on horses, i. 199. 

 Structure, degrees of utility of, i. 



249. 

 Struggle for existence, i. 75. 

 Succession, geological, ii. 89. 



of types in same areas, ii. 121. 



Swallow, one spedes supplanting 



another, i. 93. 

 Swaysland, Mr., on earth adhering 



to the feet of migratory birds, ii. 



148. 

 Swifts, nests of, i. 355. 

 Swim-bladder, i. 230. 

 Switzerland, lake habitations of, i. 



20. 

 Sy=ttm, natural, ii. 204. 



T. 



Tail of giraffe, i. 245. 



of aquatic animals, i. 246. 



, prehensile, i. 294. 



, rudimentary, ii. 260. 



Tanais, dimorphic, i. 55. 



Tarsi, deficient, i. 168. 



Tausch, Dr., on umbelliferaB, i. 271. 



Teeth and hair correlated, i. 179. 



, rudimentary, in embryonic, 



calf, ii. 255, 292. 



Tegetmeier, Mr., on cells of bees,i. 

 316, 352. 



Temminck, on distribution aiding 

 classification, ii. 211. 



Tendrils, their development, i. 

 305. 



Thompson, Sir W., on the age of 

 the habitable world, ii. 83. 



, on the consolidation of the 



crust of the earth, ii. 275. 



Thouin, on grafts, ii. 19. 



Thrush, aquatic species of, i. 222. 



, mocking, of the Galapagos, ii. 



192. 



, young of, spotted, ii. 241. 



, nest of, i. 364. 



Thuret, M., on crossed fnci, ii. 15. 



Thwaites, Mr., on acclimatisation, 

 i. 174. 



Thylacinus, ii. 220. 



Tierra del Fuego, dogs of, i. 328. 



, plants of, ii. 169. 



Timber-drift, ii. 145. 



Time, lapse of, ii. 51. 



by itself not causing modifica- 

 tion, i. 126. 



Titmouse, i. 220. 



Toads on islands, ii. 182. 



Tobacco, crossed varieties of, ii. 38. 



Tomes, Mr., on the distribution of 

 bats, ii. 184. 



Transitions in varieties rare, i. 208. 



Traquair, Dr., on flat-fish, i. 293. 



Traulschold, on intermediate varie- 

 ties, ii. 66. 



Trees on islands belong to peculiar 

 orders, ii. 182. 



with separated sexes, i. 123, 



Trifolium pratense, i. 90, 117. 



incarnatum, i. 117. 



Trigonia, ii. 99. 



Trilobites, ii. 83. 



, sudden extinction of, 99. 



Trimen, Mr., on imitating-iusects, 

 ii. 224. 



Trimorphism in plants, i. 55; ii. 29. 



Troglodytes, i. 364. 



Tuco-tuco, blind, i. 170. 



Tumbler pigeons, habits of, heredi- 

 tary, i. 327. 



