Part 25

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.