INDEX 



755 



Opossums, 496 

 Opsonins, 151 

 Optic chiasma, 339 



cup, 537, 677 



lobes, 336, 386, 415, 461 



thalami, 387, 461 



vesicles, 639 

 Oral cone of Hydra, 90 



of Obelia, 103 



hood, 300, 302 

 Orbit of dogfish, 316 



of frog, 355 



of pigeon, 402 



of rabbit, 428 

 Orca gladiator, 487 

 Order, 25, 708 

 Organic compounds, 9 



evolution, 709 

 Organisation, 16 

 Organiser, 675 

 Organism, 16 

 Organs, 15, 527 



vestigial, 715 

 Origin of muscle, 422, 539 



of species, 706 

 Omithodorns moubata, 223 

 Ornithorhynchns, 496, 579 

 Oronasal groove, 311 

 Orthoptera, 249 

 Oryctolagus cimiculus, 417. 



Rabbit 

 Osculum, 82 



Os innominatum, 436, 563 

 Osmosis, 194, 453 

 Osmotic pressure, 31, 234 



regulation, 31, igj, 210, 332 

 Osphradium, 280 

 Ossicles, auditory, 428, 430, 586 



of crayfish, 205 



of starfish, 287, 289 

 Osteichthyes, 545, 560 

 Osteoclast, 519 

 Osteocytes, 518 

 Ostia of cockroach, 235 



of crayfish, 205 



of sponges, 84 

 Ostracoda, 221 

 Ostracoderms, 553 

 Ostriches, 550 

 Otter, 489 

 Ovaries of Ascaris, 138 



of cockroach, 237 



of crayfish, 216 



of earthworm, 173 



of frog, 380 



of Hydra, 99 



of leech, 286 



of liver fluke, 122 



Ovaries of lizard, 619 



of mammal, 540 



of rabbit, 457 



of whiting, 469 

 Ovary of dogfish, 335 



of pigeon, 414 

 Oviducts of Ascaris, 357 



of cockroach, 237 



of crayfish, 216 



of dogfish, 335 



of earthworm, 173 



of frog, 381 



of leech, 183 



of liver fluke, 123 



of lizard, 619 



of pigeon, 414 



of rabbit, 457 



of snail, 269 



of Vertebrata, 617, 679 



origin of, in chick. 657 

 in tadpole, 643 

 Ovipositor, 261 

 Ovotestis, 269 

 Ovulation, 457, 471 

 Ovum, 5 



maturation of, 694 



of birds, 414, 644 



of crayfish, 217 



of dogfish, 335 

 See of frog, 629 



of hamster, 66 « 



of lancelet, 620 



of mammals, 663 



of man, 3 



segmentation of, 643 



See also Reproduction 

 Ox, foot of, bones of, 493 

 Oxygen, 8, 10, 21, 454 

 Oxyuris, 146 



Pachytene stage, 692 

 Pain, 465 

 Palaeontology, 711 

 Palate, 438, 475 



false, 429 



hard, 438 

 Pallial line, 271 

 Pallium, 387, 460 

 Palm, 418. See Metacarpus 

 Palps of Nereis, 177 



labial and maxillary, of cock- 

 roach, 229 



labial, of mussel, 274 



maxillary, of gnat, 243 

 Paludrine, 77 

 Pancreas, 530 594 



of dogfish, 324 



