Part 81

Play of animals, 112

Plethodon cinereus erythronotus, habits, 117 larval state, 117

Poduridæ, behavior and habitat, 136 movements, 136

Poisons, physiological effect of certain, 99

Pollination, animals in relation to, 141

Pollination of flowers, animals in relation, 141, 142

Pollination of Yucca, 142

Pond, fauna, 148 fish, ecological succession, 133 habitat, 148 Isopods, 106

Pond snail, behavior, 120

Pond, solution, 148

Ponds, seasonal succession in old forest, 140

Porcupine mountains, 91

Postglacial dispersal of biota, 91

Potassium cyanide, effects on sea-urchin, 99

Potato beetles, see Leptinotarsa

Predaceous beetles, food, 126, 130

Preservation of specimens, 49, 50

Preserves, natural, 34, 38

Principles, value of general, 41

Process, animal behavior as a, 102

Process method, application, 86 of investigation, 56

Process of adjustment, 30, 31 in organisms, 122

Process of response, 4

Process standpoint, 91, 101 applied to vegetation, 88

Processes, geologic, 86 of behavior, 93 of development, 93 of growth, 93 of metabolism, 93 of research, 55 regulatory character of physico-chemical and physiological, 85 standpoint, 80, 81, 82

Production, conditions of, in the sea, 87

Proof, correction, 68

Proof-reading, 65, 68