st primitive backboned animals, 92; 94; 157;
embryos of, 171.

Fiske, 139.

Flies, may, 259.

Flounder, a variant of the fish theme, 66.

Fossilization, conditions of, 77-78.

Fossils, 73-105;
remains of, 73;
groups, 77; 78, 79;
order of succession, 91;
oldest rocks devoid of, 92;
forms, 99.

Fowl, game cock, 138;
pigeons, 138.

Frog, 45;
eggs of, larva, development of, 58, 59, 60, 68.

Galapagos Islands, 102, 103, 104.

Galton, 142, 147;
heredity of mental qualities, 232.

Gametes, 252.

Gastrula, 68.

Gemmules, 143.

Genera, 32.

Generation, spontaneous, 78.

Geographical distribution, 32.

Geological agencies, rain, rivers, glaciers, 88;
construction, volcanoes, 88.

Geology, data of, 83, 84.

Germ, Bonnet's idea of, 70;
cells, 144, 146;
plasm, 145, 146.

Gibbon, 163.

Gills, 58, 62.

Gill-slits, bars, clefts, 61, 62, 64;
in embryos of lizards, birds, mammals, 69; 171.

Giraffe, 133.

Glaciers, alterations made by, 87.

Goats, 157.

Gorilla, 163, 165, 195.

Grand Canon of the Colorado, 85, 90.

Gravitation, 155.

Guinea-pigs, Brown-Sequard's, 148.

Gulick, 103.

Haeckel, 63, 71, 184.

Haemoglobin, 22.

Hapalidae, 160.

Harvey, 70.

Hawaiian Islands, 103;
snails of, 104.

Heredity, 142;
a real human process, 175;
instinct determined by, 206;
Anglo-Saxon, 213;
of mental qualities, 232.

Heron, 44.

Hesperornis, 99.

Hippopotamus, 42.

Hominidae, 160.

Homo sapiens, 183.

Hoofed animals, 95, 96, 97.

Hornets, communities of, larvae of, 260.

Horse, 41, 42, 65;
place of in zooelogical science, 95, 96;
development of, 97;
perfection of one type of, 136, 157; 167;
intelligence of, 209.

House-fly, eggs of, 67.

Human faculty, 212;
its three constituents, 212.

Huxley, 6, 26, 30, 63, 184.

Hydra, 50, 51, 52, 53, 68, 69;
comparative study of, 204, 205, 206; 254;
cells of, 255; 256, 257, 258, 261, 262, 263, 265, 266.

Hydrogen, 25, 27.

Hyracotherium, 96.

Ichthyornis, 99.

Ichthyosaurus, 94.

Indians, American, pictography of, 223, 224;
of Brazil, 227;
life of, 272.

Individual development, a resume of history of species, 63.

Inertia, 155.

Infant, human, activities of, 216.

Ingestive structures, 17.

Inheritance, 110, 131;
biological laws of, 142;
paternal and maternal basis of, 144; 145;
Mendelian phenomena of, 146;
Galton's Law of, 147;
laws of