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 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.
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, 393.
Faults, 285.
Faunas, marine, 348.
Fear, instinctive, in birds, 212.
Feet of birds, young molluscs adhering to, 385.
Fertility of hybrids, 249.
from slight changes in conditions, 267.
of crossed varieties, 267.
Fir-trees destroyed by cattle, 71.
, 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, 287.
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, 239.
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.
