538 



INDEX 



Oral groove, 294 



ring, 368 

 Orbicularis oris, 116 

 Oreaster, 359 

 Organ, 58 

 Organogenesis, 217 

 Organs and systems, development, 217 

 Oriental region, 473 

 Origin, common center of, 498 



of species, 37, 480 

 Orohippus, 492, 493 

 Osphradium, 378 



Ossicles, 356, 384, 187, 220, 363, 402 

 Osteomalacia, 175 

 Ostium, 143 

 Ostracods, 412 

 Otocysts, 152 

 Ova, 55, 142, 209 

 Ovaries of frog, 95 

 Overproduction, 507 

 Oviducts, 96, 143 

 Oviparous animals, 193, 391 

 Ovipositor, 423 

 Ovulation, 145, 224 

 Oxidase, 169 

 Oxyhemoglobin, 176, 179 

 Oxytricha, 273 

 Oyster, 373 



drill, 391 



Pagurus, 410 

 Palaearctic region, 473 

 Palate, cleft, 228 

 Paleozoology, 22 

 Pancreas, 124, 205, 207 

 Pancreatic juice, 171, 172 

 Pandorina, 277 

 Pantothenic acid, 175 

 Papillae, adhesive, 151 

 Papula, 356 

 Paradidymis, 142 

 Paragonimus, 324, 450 

 Paragordius, 337 

 Paramecium, 293 

 Paramylum, 284 

 Parapodia, 344 

 Parasite, the successful, 430 

 Parasites, accidental, 429 



facultative, 429 



infection and transmission, 433 



obligate, 430 



perfect, 433 



permanent, 430 



protozoan, 435, 440 



representative, 440 



temporary, 430 

 Parasitic Arthropoda, 439 



Nemathelminthes, 438 



Platyhelminthes, 487 



Parasitism, and host specificity, 434 



animal, 428 



degrees of, 429 



factors of, 435 



origin of, 429 

 Parathormone, 198 

 Pal-athyrin, 198 

 Parathyroid glands, 198 

 Parenchyma, 326 

 Parietal connective, 351 

 Parthenogenesis, 62, 193 

 Pasteur, Louis, 37 

 Patella, 115 

 Pathology, 21 

 Pectoral girdle, 86 

 Pedal ganglia, 388 

 Pedicellariae, 358, 363 

 Pedigree of horse, 492 

 Peking man, 494 

 Pelecypoda, 373 

 Pellagra, 175 

 Pellicle, 295 

 Pelmatohydra, 311 

 Pelvic girdle of frog, 87 



of rat, 114 

 Penaeus, 414 

 Penial setae, 339 

 Penis, 109, 143, 222 

 Pennatula, 311 

 Pennatulacea, 311 

 Pentacrinus, 361 

 Pepsin, 69, 122, 169 

 Peptones, 122, 171 

 Perch, 148 

 Pereiopods, 397, 398 

 Peribranchial grooves, 156 

 Pericardial sinus, 402 

 Pericardium, 76, 126 

 Pericolpa, 308 

 Perineal region, 109 

 Peripatus, 395, 483 

 Periphylla, 308 

 Peristalsis, 159 

 Peristaltic contractions, 318 

 Peristome, 363 

 Peristomium, 344 

 Peritoneum, 69 



of earthworm, 346 



of starfish, 363 

 Peritrichida, 273 

 Perivisceral sinus, 403 

 Peromedusae, 308 

 Phagocytosis, 180 

 Phalanges of rat, 114 

 Pharyngeal clefts, 146 

 Pharynx, 122 

 Phenotypes, 241 

 Phoronidea, 24 

 Photosynthesis, 28 

 Phototropism, 278, 325 



