446 



ON THE ORIGIN OF SPECIES 



Dogs, fertility of breeds together, 



228. 



of crosses, 240. 



proportions of, when young, 



399. 

 Domestication, variation under, 7. 

 Downing, Mr., on fruit-trees in 



America, 77. 

 Downs, North and South, 256. 

 Dragon-flies, intestiDes of, 171. 

 Drift- timber, 324. 

 Driver-ant, 216. 



Drones killed by other bees, 182. 

 Duck, domestic, wings of, reduced, 



10. 



logger-headed, 163. 



Duckweed, 346. 

 Dugong, affinities of, 373. 

 Dung-beetles with deficient tarsi, 



122. 

 Dyticus, 346. 



Earl, Mr. W., on the Malay Archi- 

 pelago, 355. 



Ears, drooping, in domestic ani- 

 mals, 11. 



rudimentary, 408. 



Earth, seeds in roots of trees, 324. 



Eciton, 214. 



Economy of organisation, 134. 



Edentata, teeth and hair, 131. 



fossil species of, 305. 



Edwards, Milne, on physiological 

 divisions of labour, 105. 



on gradations of structure, 



174. 



on embryological characters, 



377. 



Eggs, young birds escaping from, 

 79. 



Electric organs, 173. 



Elephant, rate of increase, 60. 



of glacial period, 128. 

 Embryology, 394. 

 Existence, struggle for, 56. 



conditions of, 185. 



Extinction, as bearing on natural 

 selection, 99. 



of domestic varieties, 101. 



285. 



Eye, structure of, 168. 



correction for aberration, 181. 



Eyes reduced in moles, 124. 



Fabre, M., on parasitic sphex, 

 196. 



Falconer, Dr., on naturalisation of 



plants in India, 60. 



on fossil crocodile, 281. 



on elephants and mastodons, 



300. 



and Cautley on mammals of 



sub-Himalayan beds, 305. 



Falkland Island, wolf of, 353. 



Faults, 255. 



Faunas marine, 313. 



Fear, instinctive, in birds, 190. 



Feet of birds, young molluscs ad- 

 hering to, 346. 



Fertility of hybrids, 224. 



from slight changes in con- 

 ditions, 239. 



of crossed varieties, 240. 



Fir-trees destroyed by cattle, 66. 



pollen of, 182. 



Fish, flying, 164. 



teleostean, sudden appearance 



of, 273. 



eating seeds, 325, 347. 



- fresh-water, distribution of, 



344. 

 Fishes, ganoid, now confined to 



fresh water, 97. 



electric organs of, 173. 



ganoid, living in fresh water, 



288. 



of southern hemisphere, 337. 



Flight, powers of, how acquired, 



164. 

 Flowers, structure of, in relation 



to crossing, 83. 

 of compositae and umbel- 



liferse, 131. 

 Forbes, E., on colours of shells, 



120. 



on abrupt range of shells in 



depth, 157. 

 - on poorness 



of palaeonto- 



logical collections, 258. 



— on continuous succession of 

 genera, 284. 



— on continental extensions, 



320. 



on distribution during glacial 



period, 329 

 - on parallelism 



in time and 



space, 368 

 Forests, changes in, in America, 



69. 

 Formation. Devonian, 299. 

 Formations, thickness of, in 



Britain, 254. 



