Sociology, a branch of ecology or ethology, 132 relation to ecology, 10, 11, 12 Soil, animal life influenced by humus and tillage, 100 animals of the, 86 fauna of Alps, 144 influence upon insects, 135 Soils, moisture, 62 study, 58 Solitary wasps, habits, 116, 117 habits in Texas, 113 instincts, 116 Solution pond, fauna, 148 South Africa, insects, 128 South Carolina, natural oyster grounds, 111 Sow bug, eyes, 110 Space, perception by tortoises, 121 Sparrow, field, 117 fox, 117 song, 117 tree, 117 vesper, 117 white-crowned, 117 white-throated, 117 Spawning habits of fish, 112 Specimens, collecting natural history, 63 collection, 49, 50 determination, 49, 51 determined, 52 numbering, 50, 51 preservation, 49, 50 Spiders, cocooning habits, 118 collecting, 58 habitats, 125, 138 habits, 117 instincts, 117 mating habits, 115 mental powers, 117 Nearctic, 72 systematic literature, 71 Sponges, behavior, 116 reactions, 116 Squirrels, behavior, 121 habits, 115 Stable plant formations, 88 Starfish, behavior, 105 locomotion, 110 natural history, 115 Status, dynamic, 29, 31 Stimulations, responses to chemical, 97 Stimuli, influence upon growth, 95 influence upon protoplasm, 95 similar effects of diverse, 98 Stones, fauna under, 144 Stratigraphy, relation of marine bionomy to, 22 Stream, animals of a small, 147, 148 environment, references to, 113 fish, ecological succession, 133 fish of a small, 147 habitat, 147, 148 Isopods, 106 Stress, condition, 30, 31 Struggle among organisms, 123 Struggle for existence, 2, 122, 123 in a lake, 123 in Guiana forests, 124 in the sea, 123 references, 126 Studies, quantitative, 61 Style brief, Wistar Institute, 68 Style manual, 68 Subterranean. _See also_ Cave Subterranean animals, 58, 86, 143, 144, 145 Subterranean Isopods, behavior, 108 Succession, animals in oyster beds, 131 associations of inland habitats, 91 Succession, beetles, 145 ecological, 101 ecological, birds, 21, 124, 133 ecological, in the grave, 144 ecological, on oyster reef, 112 in stages of decay, 144, 146 mammal, 145 mollusks, 137 seasonal, 140 Successions, initiated by insects, 127 Suggestions to authors, 68 Summer-bird life near Havana, Illinois, 146 Surgery, emergency, 65 Surveying, 65 Surveys, ecological, 23, 67 ecological training for, 32 natural history, 23, 30 non-ecological, 31 _Sycotypus_ eating oysters, mussels, and clams, 110 Symbiosis, 127, 128, 130 _Talorchestia longicornis_, habits and life history, 119 Tanganyika problem, 89 Taste, fish’s organ of, 112 Taxonomy, 54 relation to ecology, 8 Teaching, relation to ecology, 13