INDEX 



867 



Organic evolution, 695ff. 



Organizer, 135 



Oriental realm, 736 



Orientation response, 342 



Origin, 401 



Ornithischia, 462, 724, 840 



Ornithorhynchus, 491, 842 



Orthogenesis, 707 



Orthoptera, 316, 837 



Orycteropus, 842 



Osculum, 172 



Osmosis, 51 



Osmotic pressure, 52, 556 



Osprey, 470 



Ostariophysi, 839 



Osteichthyes. 389, 437, 839 



Osteoblasts, 57 



Ostium, 570 



Ostracoda. 303, 836 



Ostracoderms, 427, 723, 839 



Ostriches, 481 



Otic capsules, 397, 508 



Otolith, 109, 386, 581 



Outbreeding, 681 



Ovary, 119, 412, 566 



Overpopulation, 829 



Overwintering, 225 



Oviduct, 123, 413, 435 



Oviparous, 125, 436 



Ovisac, 413 



Ovoviviparous, 125, 436 



Ovulation, 566, 630 



Ovum, 122 



Owen, Richard, 11 



Oxygen, 89 



Oxygen debt, 103 



Oxygen dissociation curves, 91 



Oxygen transport, 90, 539, 540 



Oxyhemoglobin, 539 



Oxytocin, 622, 634 



Oxyuroidea, 834 



Oysters, 256 



Pacemaker, 553 

 Paired appendages, 432 

 Pair-feeding, 6 

 Palaearctic realm, 736 

 Palaeognathae, 481, 841 

 Palate, 488 

 Paleocene epoch, 725 

 Paleontology, 427, 716 

 Paleoptera, 313, 837 

 Paleosimia, 741 

 Paleozoic era, 721 

 Palolo worms, 280 

 Palpigradi, 835 

 Palps, 253, 270, 295 



Pancreas, 521 



islet cells of, 615 

 Pancreatic duct, 406, 521 

 Pangolins, 494 

 Panotheria, 842 

 Paper, scientific, 2 

 Parallel evolution, 494 

 Paramecium, 161, 763, 832 



sex cycle in. 168 

 Paramyluin bodies, 1 52 

 Paranthropus, 743 

 Paiapithecus, 741 

 Parapodia, 268 

 Parasites, attachment of, 816 



evolutionary loss of organs in, 818 



host specificity of, 819 



intestinal. 806 



intracellular, 813 



transmission of, 816 

 Parasitism. 79. 231. 765, 799-821 



adaptations to, 816 



origin of, 799 

 Parasympathetic system. 594 

 Parathormone, 614 

 Parathyroid glands, 518, 614 

 Parazoa. 236 

 Parentage tests, 678 

 Parietal bones, 51 1 

 Parietal cells, 519 

 Parietal pericardium. 403 

 Parietal peritoneum, 403 

 Parotid glands, 516 

 Parthenogenesis. 1 24, 225 

 Partial pressure of gas, 87 

 Parturition, 634 

 Passer, 841 



Passeriformes, 481, 841 

 Pasteur, Louis, 66 

 Pauropoda, 837 

 Pavlov, Ivan, 524, 589 

 Pearl button, 258 

 Pearl, cultured, 257 

 Pearl oysters, 256 

 Peat, 756 

 Pecten, 258, 317 

 Pectoral fins. 508 

 Pectoral girdle, 400, 474, 508, 512 

 Pectoralis muscle, 514 

 Pedal ganglia, 256 

 Pedal glands, 222 

 Pedicellariae, 367 

 Pediculus, 837 

 Pediculus humanus, 803 

 Pedipalps, 322 

 Peking man, 746 

 Pelagic zone, 795 

 Pelecaniformes, 841 

 Pelecanus, 841 

 Pelecypoda, 252, 256, 834 



