EXISTENCE. 



INDEX. 



GALAPAGOS. 



421 



Existence, condition of, 156. 

 Extinction, as bearing on natural 



selection, 90. 

 of domestic varieties, 87. 



Eye, structure of, 135. 



, correction for aberration, 153. 



Eyes, reduced in moles, 102. 



F. 



Fabre, M., on hymenoptera fighting, 



64. 



, on parasitic sphex, 202. 



, on Sitaris, 370, 371. 



Falconer, Dr., on naturalisation of 



plants in India, 47. 



on elephants and mastodons, 287. 



and Cautley, on mammals of 



sub-Himalayan beds, 292. 

 Falkland Islands, wolf of, 329. 

 Faults, 251. 

 Faunas, marine, 298. 

 Fear, instinctive, in birds, 197. 

 Feet of birds, young molluscs adhering 



to, 324. 

 Fertilisation variously effected, 144, 



151. 



Fertility of hybrids, 222. 

 , from slight changes in con- 

 ditions, 235. 



of crossed varieties, 239. 



Fir-trees destroyed by cattle, 52. 



, pollen of, 153. 



Fish, flying, 131. 



, ieleostean, sudden appearance 



of, 267. 



, eating seeds, 307, 325. 



, fresh -water, distribution of, 



322, 323. 

 Fishes, ganoid, now confined to fresh 



water, 78. 



, electric organs of, 140. 



, ganoid, living in fresh water, 



278. 



, of southern hemisphere, 317. 



Flat-fish, their structure, 173. 

 Flight, powers of, how acquired, 130, 



131. 

 Flint-tools, proving antiquity of man, 



13. 

 Flower, Prof., on the larynx, 178. 



, on Halitherium, 283. 



, on the resemblance between 



the jaws of the dog and Thylacinas, 



351. 



Flower, Prof., on the homology of the 



feet of certain marsupials, 3"o9. 

 Flowers, structure of, in relation to 



crossing, 68. 

 , of composite and umbelliferae, 



108, 161. 



, beauty of, 151. 



, double, 215. 



Flysch formation, destitute of organic 



remains, 254. 

 Forbes, Mr. D., on glacial action in 



the Andes, 315. 



, E., on colours of shells, 99. 



, on abrupt range of shells in 



depth, 126. 

 , on poorness of palaDontological 



collections, 253. 

 , on continuous succession of 



genera, 274. 

 , on continental extensions, 303, 



304. 

 , on distribution during Glacial 



period, 310. 

 , on parallelism in time and 



space, 339. 



Forests, changes in, in America, 54. 

 Formation, Devonian, 287. 



, Cambrian, 269. 



Formations, thickness of, in Britain, 



251. 



, intermittent, 260. 



Formica, rufescens, 202. 



, sanguinea, 202. 



, flava, neuter of, 216. 



Forms, lowly organised, long en- 

 during, 92, 93. 



Frena, ovigerous, of cirripedes, 139. 

 Fresh -water productions, dispersal of, 



322. 

 Fries, on species in large genera being 



closely allied to other species, 42. 

 Frigate-bird, 133. 

 Frogs on islands, 329. 

 Fruit-trees, gradual improvement of, 



25. 



in United States, 61. 



, varieties of, acclimatised in 



United States, 106. 

 Fuci, crossed, 228, 232. 

 Fur, thicker in cold climates, 100. 

 Furze, 365. 



0. 



Galapagos Archipelago, birds of, 327 

 productions of, 332, 333. 



