Cuckoo, instinct of, 216.

Currants, grafts of, 262.

Currents of sea, rate of, 359.

Cuvier:  on conditions of existence, 206. on fossil monkeys, 303.

Cuvier, Fred., on instinct, 208.

Dana, Professor:  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 umbelliferae, 146. on general affinities, 430.

De Candolle, 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, 285.

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.

Duckweed, 385.

Dugong, affinities of, 414.

Dung-beetles with deficient tarsi, 135.

Dyticus, 386.

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 embryological characters, 418.

Eggs, young birds escaping from, 87.

Electric organs, 192.

Elephant:  rate of increase, 64. of glacial period, 141.

Embryology, 439.

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.