nd apes compared, 88.

Eaton, Rev. A. E., on wingless insects, 70.

_Echinodermata_, 125-127, 138, 155.

Ectoderm, 137-142.

Egg, _see_ Ovum.

Eimer, 363.

_Elaps fulvius_ imitated by non-venomous snakes, 330.

Electric organs, 365-373.

Elephant, foot of, 185, 186;
rate of propagation of, 261, 262.

Elk, 196-198, 199.

Embryo, human, _see_ Man.

Embryogeny, _see_ Ontogeny.

Embryology, 98-155.

Embryos, comparative series of, 152, 153.

_Encyclopaedia Britannica_, eighth ed., on instinct, 289-291.

Encystation of Protozoa, 115.

Endoderm, 137-142.

Equatorial plate, 129.

_Equus_, _see_ Horse.

_Erythrolamprus venustissimus_, 330.

Evolution, organic, fact of, Section I;
Method of, Section II;
ideas upon, prior to Darwin, 253-258;
divergent, 266, 267.

Ewart, Professor Cossar, on electric organ of skate, 364, 367.

Existence, _see_ Struggle for.

Eye, of octopus, 57, 58, 347-350;
absence of, in dark cave animals, 70-72;
nictitating membrane of, 74, 75;
development of, from cutaneous nerve-ending, 352-354.

F.

Feet, 51-59, 66, 77-80, 174-192, 197.

Fertilization of ova, 127, 128;
of flowers by insects, 406.

Fish, embryology of, 143-155;
palaeontology of, 163, 165, 169-171;
brain of, 194-197;
distribution of, 224-246;
flying, 355.

Fission, reproduction by, 106, 107.

Flat fish, 317.

Float, _see_ Swim-bladder.

Flowers, fertilization of, by insects, 406.

Fly, imitating a wasp, 329.

Flying-fish, and squirrels, 355.

_Foraminifera_, 346.

Forbes, H. O., on scapulo-coracoid bones of _Dinornis_, 60.

Fortuitous, Darwin's use of the word, 340.

Fossils, _see_ Palaeontology.

Frogs, 317.

G.

Galapagos Islands, 227-231, 236, 237.

_Galeus_, eye of, 75.

Galls, vegetable, 293-295, 446-448.

Gastraea, 137-140.

_Gastrophysema_, 138.

Gastrulation, 137, 140.

Gegenbaur, 147, 181.

Gemmation, reproduction by, 106, 107, 110, 111.

Generalization, 5.

Generalized types, 33.

Genesis, classification of organic nature in, 23.

Genial tubercle, 96.

Geographical distribution, 204-248;
_see_ Glacial period, Barriers Transport of organisms, Oceanic
islands, &c.

Geology, record of imperfect, 156-160, and Appendix;
_see_ Palaeontology.

Germs, prophetic, 272, 351-362.

Gesner, on classification, 24;
on canaries, 313.

Gill-arches, 146, 147, 150, 151.

Gill-slits, 146, 147, 150-153.

Gills, of young sala