INDEX 



607 



Pelvic region, 31G 



Pelvis, 319-321, 423 



Pen, squid, 222 



Penaeus, 265, 266 



Penaeus semsulcatus, 266 



Penguins, 401 



Penis, 160, Kil 



Pennaria, 144 



Pennsylvanian period, 511, 514, 515 



Pepsin, 322, 401, 464 



Pepsinogen, 404 



Peptones, 323 



Perca flavescens, 346 



scale, 347 

 Perch, 346 



climbing, 358 

 scale, 347 

 Perching birds, 401 

 Perching mechanism, 401 

 Perennibranchs, 304 

 Peribranchial vesicle, 312 

 Pericardial cavity, 210, 212, 297, 317, 408 

 Pericardial glands, 400 

 Pericardial sinus, 254 

 Pericardium, 252 

 Perioral membrane, 192 

 Periosteum, 104, 320 

 Periostracum, 209, 210 

 I'eripatus, 268, 499 

 Peripheral nervous system, 233, 327 

 Perisarc, 430 

 Perissodactyla, 416 

 Peristalsis, 231, 461 

 Peristomal tentacles, 242 

 Peristome, 09, 192 

 Peristomium, 242, 243 

 Peritoneum, 193, 195, 230, 317 

 Permian period, 511, 515 

 Personality, 453 

 Perspiration, 439, 456, 463 

 Petrifaction, 510 

 Petromyzon marinus, 335 

 Petromyzontia, 335 

 Pfliiger, 20 

 Phagocytes, 490 

 Phalangers, 412 

 Phalanges, 321, 391 

 Phalarope, 404 

 Pharyngeal clefts, 440 

 Pharyngeal slits, 306, 308, 311, 313, 314, 372, 440, 



620, 545 

 Pharynx, 158, 166, 230, 232, 233, 276, 277, 311- 



314, 317, 322 

 Pheasants, 402, 507 



ring-necked, beak, 399 



foot, 400 

 Pheidole instabilis, 294 

 Phenotype, 528 

 Phenotypic ratios, 632, 533 

 Philodinii roseola, 186 

 Phosphorus, 18, 19 



cycle, 400 

 Photostomias guernei, 367 

 Photosynthesis, 41, 42 



Phototropism, 56, 67, 139, 234, 360 



Phyla, 58, 542, 546, 547 



table, 544-545 

 Phyllium, 486 

 Phylogenetic series, 516 

 Phylogenetic tree, 517, 542, 546, 647 

 Phylogeny, 267 

 Physnlia pelagica, 148 

 Physical environment, 488 

 Physical factors, 479 

 Physics, 7 



Physiological differentiation, 93 

 Physiological life histories, 478 

 Physiological state, 56, 74, 140, 163, 234, 471, 473 

 Physiology, 4, 5, 553-554 

 Pia mater, 369 

 Pig, embryo, 520 



foot bones, 415 

 Pigeons, 405 



anatomy, 394 



limb skeletons, 391 

 Pigment cells, 350, 359 



(See also Chromatophores and Eyespots) 

 Pigment layer, eye, 332, 333 

 Pigment spots, 149, 197, 314 

 Pike, scale, 347 

 Pilidium, 184 

 Pill bugs, 262 

 Piltdown man, 424 

 Pincer, 250 

 Pine marten, 509 



Pineal body, eye, or gland, 337, 340, 361, 370, 387 

 Pinna, 330, 400 

 Pinnipedia, 414 

 Pisces, 334, 344 



(See also Fishes) 

 Pit vipers, 386 

 Pithecanthropus, 424 

 Pituitary body or gland, 396, 464, 466 

 Pituophis sayt, head, 383 

 Place of origin, 500 

 Placenta, 412, 418-421 

 Placoid scale, 338, 339, 347, 348 

 Planaria maculata, 157 

 Planarians, 157-105, 450, 463, 466 

 Planes of metabolism, 455 

 Plankton, 352, 478, 483 

 Plant lice, 105, 284, 285. 463 

 Plantigrade foot, 414 

 Plants, compared with animals, 40 



contrasted with animals, 41 



relations to animals, 477 

 Planula, 149, 160 

 Plasma, 231, 324 



membrape, 28, 30 

 Plasmagel, ^5, 66 

 Plasmalemma, 03, 65, 66 

 Plasmasol, 66 

 Plasmodium, 90 

 Plasmodium vivax, 90 

 Plasmosome, 29, 30 

 Plastids, 30, 31 

 Plastron, 388, 389 

 Platyhelminthes, 164, 544, 547 

 Platyhelminths (see Flatworms) 



