Hominidæ, 160.
Homo sapiens, 183.
Hoofed animals, 95, 96, 97.
Hornets, communities of, larvæ of, 260.
Horse, 41, 42, 65; place of in zoölogical 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.