714 
Octopus Bairdii, 262 
Odonata, 348 
Odontophore, 256 
Odontornithes, 587, 557 
Ccodoma, 882 
Oligochaeta, 174 
Onchidium, 257 
Oniscus murarius, 287 
Operculum of gastropoda, 261 
Ophidia, 496, 517 
Ophiocoma vivipara, 192 
Ophiopholis bellis, 192 
Ophiuridea, 191, 198 
Opisthodelphys ovifera, 485 
Opisthomi, 446 
Opossum, 575 
Orang, 622 
Orca gladiator, 595 
Oreortyx pictus, 546 
Organisms, 6, 23 
Organs, comparative anatomy of, 
631 
of circulation, 635 
of digestion, 631 
of respiration, 637 
of sense, 640 
of smell, 642 
nature of, 4, 6, 8, 9 
Origin of species, 671 
Ornithodelphia, 571, 628 
Ornithosauria, 516 
Orohippus, 602 
Orthagoriscus oblongus, 462 
Orthoptera, 345 
Oscines, 552, 553 
Oscula of sponges, 438 
Osmerus eperlanus, 452 
mordax, 452 
Osprey, 548 
Ostracoda, 279 
Ostrich, 589 
Otocyst, 270, 641 
of clam, 245 
of worms, 101 
INDEX, 
Ova, winter, of planarians, 103 
of polyzoa, 145 
of Rotatoria, 136 
Ovibos moschatus, 610 
priscus, 610 
Ovis argali, 610 
aries, 610 
montana, 610 
Owl, 548 
Ox, 612 
Oxyuris vermicularis, 125 
Oyster, pearl, 232 
PADDLE FIsH, 427 
Palevcaris typus, 272 
Paleontology, 16 
Palamedea cornuta, 546 
Palapteryx, 538 
Palechinida, 205, 208 
Palisade worm, 126 
Paludicella, 140 
Pandion halia&ttus, 548 
Pangolin, 580 
Panopea arctica, 230 
Paragorgia arborea, 86 
Paramecium caudatum, 35 
Parr, 452 
Parroquet, 550 
Parrot, 550 
Parthenogenesis, 54, 652 
in ascidians, 403 
Partridge, 546 
Passeres, 551 
Patella vulgata, 248 
Pauropoda, 336, 366 
Pauropus Lubbockii, 336 
Pear] oyster, 232 
shell; 282 
Pedicellaria, 179 
Pediculati, 460 
Pedipalpi, 342 
Pelagic molluscs, 288, 249 
Pelecanus erythrorbynchus, 585, 
Pelican, 542 
