288 
Hobhouse, L., T., problem of learn- 
ing, 176 
reason in animals, 249, 276, 277 
Hodge, C. F., and Aikins, H. A., 
change of behavior in 
Vorticella, 89 
Holmes, S. J., 61, 89, 179, 231; 
behavior of Loxophyllum, 
16, 25, 35, 79-81, 141 
instincts of Amphithe, 93, 94; 
of young terns, 96, 97 
learning in crayfish, 185, 186; 
in sunfish, 223 
phototaxis of blow-fly larve, 
42, 43; of earthworm, 43, 
44, 54; of Eubranchipus, 
54; of fiddler crabs, 48, 
56, 140; of Jassa, 49; of 
Notonecta, 55; of Or- 
chestia, 46, 48, 49, 51, 55; 
of Ranatra, 48, 51, 52, 55, 
56, 140; of Talorchestia, 
42, 54 
reactions of mosquito larve to 
shadows, 142 
Holt, E. B., and Lee, F. S., 61 
Horse, locality memory, 246-248 
Hudson, W. H., 114, fear in birds, 
121-123 
Huggins, G. E., learning in cray- 
fish, 184 
Huggins, Dr., variant instinct in a 
dog, 134 
Hutchinson, W. N., 258, imitation 
in dogs, 256 
Huxley, T. H., 10 
Hyalella, change of phototaxis by 
chemicals, 50 
Hydra, geotaxis, 30 
reactions to chemicals, 28 
reactions to repeated stimula- 
tion, 141, 145 
thigmotaxis, 36 
Hydroides, reaction to repeated 
stimulation by shadows, 
142 
INDEX 
Imitation in ants, 209, 210, 254 
in birds, 254, 257 
in cats, 255 
in fishes, 253 
in monkeys, 262, 270 ff 
in raccoons, 255 
in rats, 255 
in dogs, 255, 256 
Insects, compensatory motions, 40 
geotaxis, 32 
instincts, 93, 95, 98, 104, 105, 
108, 110, 118-120, 124- 
133, 140, 191 ff 
intelligence in, 191 ff 
photokinesis, 42 
phototaxis, 42, 43, 48, 51, 55 
rheotaxis, 38 
seat of instincts, 104 
thigmotaxis, 36 
Instinct, 108 
analysis of, 21 
deferred, 96, 97 
defined, 92 
dependence on internal con- 
ditions, 110 ff 
evolution of, 115 ff 
human, 100 
illustrations of, 98, 95 
imperfection of, 95, 96 
and intelligence, 112 
internally initiated, 107 ff 
modified by experience, 166 
popular conception of, 94, 95 
and reflex action, 99 ff 
transitoriness of, 99 
variability, 131 ff 
Intelligence, beginnings of, 164 ff 
criterion of, 181 
deceptive appearances of, 159 
in amphibians, 227-229 
in apes, 260 
in birds (chick), 165, 166, 176- 
178 
in crustaceans, 182-187 
in fishes, 219-227 
in insects, 191 ff 
