716 



INDEX 



Plasma, 86, 175 



blood, 86 

 Plasmodium, 68, 69 

 Plastron, turtle, 406, 408 

 Platyhelminthes, 3, 133-148, 135, 

 607 

 bilaterally symmetrical, 133 

 classification, 147 

 organ-system levels, 133 

 origin and relations, 143 

 parasitic, 133, 138 

 relations to man, 143 

 Platypus, 480, 495 

 Platysma, 507 



Plecoptera, 229, 241, 260, 263 

 Plectognathida, 395 

 Pleistocene, 618 

 Pleopod, 205 

 Plethodon, 404 

 Plethodontidae, 397, 404 

 Pleura, 199 

 Pleural canity, 537 

 Pleurobrachia, 131 

 Pleurobranchs, 207 

 Pleuron, 233 

 Pleuronectida, 395 

 Pliocene horse, 619, 620 



period, 618 

 Pliohippus, 618, 619, 620 

 Ploceidae, 462 

 Plover. 452. 461 

 Plumage, 435 

 Plumatella, 166, 167 

 Pneumatophore, 120 

 Podicipediformes, 461 

 Podilymbus, 461 

 Podobranch, 207, 208 

 Podocyrtis, 76 

 Podophrya, 64, 66 

 Poecilosclerina, 101 

 Poison claw, 225, 226 

 fangs, 269, 270 

 gland, 269, 270, 328 

 Poisonous centipedes, 22^ 

 lizard, 422, 423 

 reptiles, 422-426 

 Polar body, 80, 115,577 

 Polian vesicle, 310 

 PoUstes, 264 

 Polistotrema, 367 

 Pollack, 394, 395 

 Pollen basket, 245, 246 

 brush, 245, 246 

 combs, 245, 246 

 packer, 245, 246 

 Pollination, 639 



Polychaeta, 171, 185, 186, 187, 

 193, 196 

 free-living, 185 

 parasitic, 185 

 Polychoerus, 147 

 Polycladida, 147 

 PolydoTa, 194 

 Polyembryony, 257, 476 



Polygenic trait, 587 

 Polygordius, 188 

 Polymastigina, 49 

 Polymorphism, 120 

 Pohodon, 390 

 Polyp, 117 



hydroid. 125 

 Polyplacophora, 282, 300 

 Polypterida, 394 

 Polypteridae, 379 

 Polysaccharides, 519 

 Polyzoa, 166 

 Pomace flies, 265 

 Pongidae, 489 

 Pons, 546 

 Populations, 633 

 Porcupine, 464, 485 



fish, 391, 393 

 Pore, 94, 96 

 birth, 140 

 cell 9 5 



excretory, 139, 140, 151 

 genital, 139, 140, 144, 309 

 gland cell, 179 

 incurrent, 94 

 renopericardial, 285 

 Porifera, 3, 92-101, 607 

 canals, 98 

 classification, 100 

 fresh-water, 99 

 morphology, 94 

 origin and relation, 99 

 physiology, 96 

 regeneration, 99 

 relations to man and other ani- 

 mals, 100 

 representatives, 93 

 reproduction, 97, 98 

 skeletons, 98 

 Porocyte, 95 

 Porpoise, 486 

 Portal vein, 338 



Portuguese man-of-war, 120, 121 

 Positive reaction, 36 

 Posterior horn, 345 

 lobe, pituitary, 553 

 mesenteric artery. 338 

 vena cava. 336, 341, 342 

 Posture, 548 

 Potato beetle, 257, 258 

 Potential immortality, 563 

 Popched mammals, 481, 482 

 Pouter, 456 

 Prairie, chicken, 453 



dog, 485 

 Prawn, 217 

 Praying mantis, 255 

 Precocial birds, 449, 450 

 Predaceous, animals, 13 

 insects, 256 

 mammals, 494 

 Predation, 636 

 Predator chain, 635 

 Prehallux, 346 



Prehensile tail, 489 

 Prehistoric man, 624 

 Premaxilla, 343, 344 

 Premolars, 475 

 Prepotency, 597 

 Primary feathers. 438 

 Primates, 464, 488, 495 

 Primitive-jawed fishes, 317 



streak, 357 

 Primordial germ cell, 115, 576, 



577, 583 

 Principles, zoological, 11 

 Prismatic layer, 283, 284 

 Probing bird, 446 

 Proboscidea, 464, 484, 496 

 Proboscidiella, 639 

 Proboscis, acorn worm, 321, 322 

 elephant, 484, 487 

 Hemichordata, 321, 322 

 insect, 248 

 Nemertina, 163 

 Procellariiformes, 433, 461 

 Producers, 635 

 Progesterone, 554 

 Proglottid, 141, 144, 146 



gravid, 144 

 Prolegs, 240 

 Pronator teres, 467 

 Pronephridium, 188 

 Pronghorn antelope, 484, 487 

 Pronotum, 233 

 Prootic, 343, 344 

 Prophase, 25, 26, 28 

 Proprioceptors, 548 

 Prorhynchus, 147 

 Prosobranchia, 282, 301 

 Prosopyle, 95, 96 

 Prostate, 192 



gland, 341, 342 

 Prostomium, 172, 173. 183, 184 

 Protective coloration, 446 



resemblance, flounder, 389 

 Proteidae. 397, 404 

 Protein, 18, 520, 542 

 Proterospongia, 99, 605 

 Proterozoic era, 617 

 Prothoracic legs, 245 

 Prothorax, 233 

 Prothrombin, 526 

 Protoceratops, 426, 428 

 Protomonadina, 49 

 Protonephridium, 319, 320 

 Protoplasm, 14-20, 15 



cellular organization, 20-29 

 chemical composition, 16 

 inorganic salts, 17 

 organic compounds, 17 

 process, 152 

 proteins, 18 

 Protopodite, 201, 203, 205 

 Protopterus, 392 

 Prototheria, 495 

 Protozoa, 3, 30-77, 78 

 ancestral, 607 



