D.

Dana, Prof., on blind cave-animals, 139. ----, on relations of crustaceans of Japan, 372. ----, on crustaceans of New Zealand, 376. De Candolle on struggle for existence, 62. ---- on umbelliferæ, 146. ---- on general affinities, 430. ----, Alph., on low plants, widely dispersed, 406. ----, ----, on widely-ranging plants being variable, 53. ----, ----, on naturalisation, 115. ----, ----, on winged seeds, 146. ----, ----, on Alpine species suddenly becoming rare, 175. ----, ----, on distribution of plants with large seeds, 360. ----, ----, on vegetation of Australia, 379. ----, ----, on fresh-water plants, 386. ----, ----, on insular plants, 389. Degradation of coast-rocks, 282. Denudation, rate of, 285. ---- of oldest rocks, 308. Development of ancient forms, 336. Devonian system, 334. Dianthus, fertility of crosses, 256. Dirt on feet of birds, 362. Dispersal, means of, 356. ---- during glacial period, 365. Distribution, geographical, 346. ----, means of, 356. Disuse, effects of, under nature, 134. Divergence of character, 111. Division, physiological, of labour, 115. Dogs, hairless, with imperfect teeth, 12. ---- descended from several wild stocks, 18. ----, domestic instincts of, 213. ----, inherited civilisation of, 215. ----, fertility of breeds together, 254. ----, ---- of crosses, 268. ----, proportions of, when young, 444. Domestication, variation under, 7. Downing, Mr., on fruit-trees in America, 85. Downs, North and South, 286. Dragon-flies, intestines of, 190. Drift-timber, 360. Driver-ant, 240. Drones killed by other bees, 202. Duck, domestic, wings of, reduced, 11. ----, logger-headed, 182. {494} Duckweed, 385. Dugong, affinities of, 414. Dung-beetles with deficient tarsi, 135. Dyticus, 386.

E.

Earl, Mr. W., on the Malay Archipelago, 395. Ears, drooping, in domestic animals, 11. ----, rudimentary, 454. Earth, seeds in roots of trees, 361. Eciton, 238. Economy of organisation, 147. Edentata, teeth and hair, 144. ----, fossil species of, 339. Edwards, Milne, on physiological divisions of labour, 115. ----, on gradations of structure, 194. ----, on embryonical characters, 418. Eggs, young birds escaping from, 87. Electric organs, 192. Elephant, rate of increase, 64. ---- of glacial period, 141. Embryology, 438. Existence, struggle for, 60. ----, conditions of, 206. Extinction, as bearing on natural selection, 109. ---- of domestic varieties, 111, ----, 317. Eye, structure of, 187. ----, correction for aberration, 202. Eyes reduced in moles, 137.

F.

Fabre, M. on parasitic sphex, 218. Falconer, Dr., on naturalisation of plants in India, 65. ---- on fossil crocodile, 313. ---- on elephants and mastodons, 334. ---- and Cautley on mammals of sub-Himalayan beds, 340. Falkland Island, wolf of, 394. Faults, 285. Faunas, marine, 348. Fear, instinctive, in birds, 212. Feet of bird, young molluscs adhering to, 385. Fertility of hybrids, 249. ---- from slight changes in conditions, 267. ---- of crossed varieties, 268. Fir-trees destroyed by cattle, 72. ---- ----, pollen of, 203. Fish, flying, 182. ----, teleostean, sudden appearance of, 305. ---- eating seeds, 362, 387. ----, fresh-water, distribution of, 384. Fishes, ganoid, now confined to fresh water, 107. ----, electric organs of, 192. ----, ganoid, living in fresh water, 321. ---- of southern hemisphere, 376. Flight, powers of, how acquired, 182. Flowers, structure of, in relation to crossing, 97. ---- of compositæ and umbelliferæ, 144. Forbes, E., on colours of shells, 132. ---- on abrupt range of shells in depth, 175. ---- on poorness of palæontological collections, 288. ---- on continuous succession of genera, 316. ---- on continental extensions, 357. ---- on distribution during glacial period, 366. ---- on parallelism in time and space, 409. Forests, changes in, in America, 74. Formation, Devonian, 334. Formations, thickness of, in Britain, 284. ----, intermittent, 290. Formica rufescens, 219. ---- sanguinea, 219. ---- flava, neuter of, 240. Frena, ovigerous, of cirripedes, 192. Fresh-water productions, dispersal of, 383. Fries on species in large genera being closely allied to other species, 57. Frigate-bird, 185. Frogs on islands, 393. Fruit-trees, gradual improvement of, 37. ---- ---- in United States, 85. ---- ----, varieties of, acclimatised in United States, 142. {495} Fuci, crossed, 258. Fur, thicker in cold climates, 133. Furze, 439.

G.

Galapagos Archipelago, birds of, 390. ----, productions of, 398, 400. Galeopithecus, 181. Game, increase of, checked by vermin, 68. Gärtner on sterility of hybrids, 247, 255. ----, on reciprocal crosses, 258. ----, on crossed maize and verbascum, 270. ----, on comparison of hybrids and mongrels, 272. Geese, fertility when crossed, 253. ----, upland, 185. Genealogy important in classification, 425. Geoffroy St. Hilaire on balancement, 147. ---- ---- on homologous organs, 434. ---- ----, Isidore, on variability of repeated parts, 149. ---- ----, on correlation in monstrosities, 11. ---- ----, on correlation, 144. ---- ----, on variable parts being often monstrous, 155. Geographical distribution, 346. Geography, ancient, 487. Geology, future progress of, 487. ----, imperfection of the record, 279. Giraffe, tail of, 195. Glacial period, 365. Gmelin on distribution, 365. Gnathodon, fossil, 368. Godwin-Austen, Mr., on the Malay Archipelago, 300. Goethe on compensation of growth, 147. Gooseberry, grafts of, 262. Gould, Dr. A., on land-shells, 397. ----, Mr., on colours of birds, 132. ----, on birds of the Galapagos, 398. ----, on distribution of genera of birds, 404. Gourds, crossed, 270. Grafts, capacity of, 261. Grasses, varieties of, 113. Gray, Dr. Asa, on trees of United States, 100. ----, on naturalised plants in the United States, 115. ----, on rarity of intermediate varieties, 176. ----, on Alpine plants, 365. ----, Dr. J. E., on striped mule, 165. Grebe, 185. Groups, aberrant, 429. Grouse, colours of, 84. ----, red, a doubtful species, 49. Growth, compensation of, 147. ----, correlation of, in domestic products, 11. ----, correlation of, 143.

H.

Habit, effect of, under domestication, 11. ----, effect of, under nature, 134. ----, diversified, of same species, 183. Hair and teeth, correlated, 144. Harcourt, Mr. E. V., on the birds of Madeira, 391. Hartung, M. on boulders in the Azores, 363. Hazel-nuts, 359. Hearne on habits of bears, 184. Heath, changes in vegetation, 72. Heer, O., on plants of Madeira, 107. Helix pomatia, 397. Helosciadium, 359. Hemionus, striped, 163. Herbert, W., on struggle for existence, 62. ----, on sterility of hybrids, 249. Hermaphrodites crossing, 96. Heron eating seed, 387. Heron, Sir R., on peacocks, 89. Heusinger on white animals not poisoned by certain plants, 12. Hewitt, Mr., on sterility of first crosses, 264. Himalaya, glaciers of, 373. ----, plants of, 375. Hippeastrum, 250. Holly-trees, sexes of, 93. Hollyhock, varieties of, crossed, 271. Hooker, Dr., on trees of New Zealand, 100. {496} ----, on acclimatisation of Himalayan trees, 140. ----, on flowers of umbelliferæ, 145. ----, on glaciers of Himalaya, 373. ----, on algæ of New Zealand, 376. ----, on vegetation at the base of the Himalaya, 378. ----, on plants of Tierra del Fuego, 374, 378. ----, on Australian plants, 375, 399. ----, on relations of flora of South America, 379. ----, on flora of the Antarctic lands, 381, 399. ----, on the plants of the Galapagos, 392, 398. Hooks on bamboos, 197. ---- to seeds on islands, 392. Horner, Mr., on the antiquity of Egyptians, 18. Horns, rudimentary, 454. Horse, fossil, in La Plata, 318. Horses destroyed by flies in La Plata, 72. ----, striped, 163. ----, proportions of, when young, 444. Horticulturists, selection applied by, 32. Huber on cells of bees, 230. ----, P., on reason blended with instinct, 208. ----, on habitual nature of instincts, 208. ----, on slave-making ants, 219. ----, on Melipona domestica, 225. Humble-bees, cells of, 225. Hunter, J., on secondary sexual characters, 150. Hutton, Captain, on crossed geese, 254. Huxley, Prof., on structure of hermaphrodites, 101. ----, on embryological succession, 338. ----, on homologous organs, 438. ----, on the development of aphis, 442. Hybrids and mongrels compared, 272. Hybridism, 245. Hydra, structure of, 190.