INDEX 



433 



Plants, chemical elements in, 48; an 

 environmental feature, 277, 281, 282 

 Planula, 186 

 Plasma, oxygen in, 149 

 Plasmolyzed cells, 67 

 Plastids, 32, 33, 255 

 Plato, 8 



Platyhelminthes, 116; classified, 269, 272 

 Plecoptera, classified, 270 

 Pleistocene, 320, 321, 323, 324, 325, 328, 



329, 336; in time scale, 315 

 Pleodorina, 87, 89, 90, 93, 176, 206 

 Pleodorina calif ornica, 89 

 Pleodorina illinoisensis, 89 

 Plesliodon fasciatus (see Skink) 

 Pliny, 9 



Pliocene, 320, 321, 324, 325, 329; in time 

 scale, 315 



Pliohippus, 324, 325, 327 



Pneumatophore, 98, 99 



Poebr other ium, 329 

 ' Poisons, glandular secretions, 154 



Polar body, 174, 211, 215; first, 213; 

 second, 213 



Polarity, 34, 89 



Pole, 74; animal, 213, 215, 220; vegeta- 

 tive, 213, 215 



Political units, 335 



Polychaeta, classified, 269 



Polychffite, 101 



Polycladida, classified, 269 



Polygijra albolabris, hermaphroditism in, 

 191; sexual organs in, 191 



Polymorphism, 97, 98, 100, 102, 278 



Polypeptides, 51 



Polyphemus, sperm of, 216 



Polyplacophora, classified, 269 



Polyps, 97, 99, 186; classified, 272 



Polystomella, 66, 68 



Porcellana, sperm of, 216 



Porifera, 64, 100; classified, 269, 272 



Porocytes, 112 



Portuguese man-of-war, 99, 100 



Postcaval vein, 132 



Posterior, 105 



Postesophageal commissure, 140 



Potato beetle (see Leptinotarsa) 



Pouch, brood, in marsupial frog, 200, 201 ; 

 in marsupials, 201; in pipe-fish, 201; 

 in sea horse, 201; in swamp-wallaby, 

 202 



Prairie chicken, range of, 292 



Prairie faunas, 281 

 28 



Prairie hare, range of, 292 

 Precocial forms, 201, 203 

 Precoracoid, 137, 138 

 Predaceous habits, 277, 280, 282 

 Preference for environmental conditions, 



284 

 Prehistoric man, 335, 337 

 Pressure, 163 



Primary oocyte, 211, 212, 213 

 Primary spermatocytes, 210, 211 

 Primates, 335; classified, 271 

 Primula, Chinese, 256 

 Priority, law of, 265 

 Proboscidea, classified, 271 

 Proboscis, of Elephas, 323; evolution of, 

 in elephants, 320; in Palseomasto- 

 don, 320; in Trilophodon, 322 

 Procellariiformes, classified, 271 

 Procoelous vertebra, 137 

 Procyon lotor, range of, 297 

 Proglottis, 101; of tapeworm Proteo- 



cephalus, figure of, 129 

 Prong-horn antelope, range of, 292 

 Pronuba yuccasella, 282 

 Prophases, 71 

 Prosecretin, 146 



Prostomium, of earthworm, 119 

 Protandrous animals, 190 

 Proteins, 39, 40, 42, 50, 51, 52, 53, 54, 57; 

 absorption of, 146; assimilation of, 

 • 146; conversion of, 144, 145; diges- 

 tion of, 144, 146; in mutation, 355; 

 oxidation of, 150; in protoplasm, 38; 

 synthesis of, 146 

 Proteocephalus, 129; figure of proglot- 

 tis, 129 

 Proteolytic enzymes, 56 

 Proteoses, 144, 145 

 Proterozoic, in time scale, 315 

 Protobranchia, classified, 269 

 Protogynous animals, 190 

 Protonema, 254 

 Protonephridial system, 125 

 Protonephridium, 125, 126 

 Protophyta, 93 



Protoplasm, 25, 26, 29, 31, 36, 39, 41, 42, 

 46, 187; chemistry of, 38; colloidal 

 nature of, 37; a colloidal system, 41; 

 contractility, 155; physical and 

 chemical processes of, 43-47; physics 

 of, 38 

 Protoplasmic movement, 60 

 Protoplasmic substances, migration of, 80 



