Part 85

Serpents, food, 129 Pennsylvania, 129

Sexual characters of Araneads, secondary, 115

Shawnee Cave plankton, ecological study, 145

Shell-fish, ciliary action, 114 feeding reflexes, 114 food, 114 function of mucus, 114

Shell-fish industries, biology, 114 culture, 114 utilization, 114

Shell-fisheries of Massachusetts, 108

Shore, animal ecology of the, 139

Shore animals, associational study, 139

Significance of courtship of Araneads, 115

Skokie Marsh area, ecology of mollusca, 137

Slaves of ants, 120

Slug, eyes, 110 feeding habits, 125

Snail, eyes, 110 mud, 111 pond, 120

Snails, and plants, 125 feeding habits, 125 food, 125 in grave, 144 influence of environment on, 100

Snout-beetles, 76

Snowbird, 117

Social community, 18, 123 animals, 131 insects, 135 interrelations, 131 oyster bank, 132 sea-bottom, 136

Social control, by voices among pigeons, 106, 134

Social life, from comparative and phylogenetic standpoint, 132 insects, 111 multiple origin, 132 origin, 132

Social parasitism, 126

Social reaction, beginnings in lower animals, 134 beginnings in man, 134

Social wasps, 117 behavior, 111

Societies, insects, 128

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