INDEX 



171 



Pecten irradians, 



economic value, 108 



growth, 108 



habits, 108 



life history, 108 

 Pennsylvania, 



crawfish, 116 



lizards, 129 



serpents, 129 



turtles, 129 

 Phase rule, 85 

 Photography, 57, 59, 61, 65 



aquatic animals, 63, 64 



birds, 39 



fish, 39 



mammals, 39 



nets of Hydropsyche (aquatic), 



64 

 Phototaxis and random movements, 



105 

 Phototropism of Mourning-cloak 



butterfly, 116 

 Phylogeny, 21, 96 



of human behavior, 133 

 Physa, biology, 110 

 Physical change, influence upon 



animals, 85 

 Physiographic ecology of Chicago, 



88 



Physiological chemistry, 95 

 Physiological classification, 



and ecological succession, 21 



in ecology, 101, 133, 134 

 Physiological conditions, 92, 93 

 Physiological life histories of plants, 



17 



Physiological problems and dy- 

 namic theory, 97 

 Physiological responses, 



distribution due to, 101, 112, 

 136 



of fish, 112 

 Physiological states and rheotaxis 



in Isopoda, 106 

 Physiology, 



comparative, 95 



general, 95 



of organisms, 96 



of organs, 96 



of reproduction, 100 



Phytogeographical nomenclature, 



22, 60 

 Pigeon, 



common, 117 



homing, 113 



passenger, 117 

 Pigeons, 



emotion in, 110 



methods of homing, 113 



voices as means of social control, 



106, 134 

 Planarians, 



behavior, 120 



distribution locally, 120 



reactions of fresh-water, 116 



reactions to light, 105 

 Plane table manual, 64 

 Plankton, 60, 148 



ecological study, 140 



investigations of Danish lakes, 140 



of Illinois river, 147 



of Shawnee Cave, ecological 

 study, 145 



organisms, 50 

 Plant animals, 128 

 Plant ecology, 59 



bibliography, 89 



general principles, 88, 89 

 Plant formations, stable and migra- 

 tory, 88 

 Plant galls, 143 



animals in relation to, 141 



biology and causes of European, 



143 

 Plant societies, 



relation to evaporation, 64, 90 



relation to humidity, 90 



study of Chicago, 88 

 Plant succession, 90 



relation to distribution of tiger 



beetles, 90 

 Plants, 



and ants, 126, 127 



and snails, 125 



forming animal habitats, 89 



influence upon insects, 135 



life histories, physiological, 17 



seasonal succession, 140 



variation, 96 

 Play of animals, 112 



