INDEX 



431 



Oosperm, 90 



Ootid, 213 



Ootype, 129, 130 



Opalina rarumim, 172 



Operculum, 122, 233 



Opliiuroidea, classified, 269, 272 



Ophthalmozoa, 263 



Opisthobranchia, classified, 269 



Opisthocoelous vertebra), 137 



Opossum, birth stages in, 201; parental 



care in, 201; range of, 292; sperm of, 



216 

 Optic lobe, 120, 141 

 Optic nerve, 227, 230 

 Optic stalk, 227 

 Oral aperture, 103, 169 

 Orbit, in camel series, 329 

 Order, in taxonomy, 262, 263, 264 

 Orders, range of, 291 

 Ordovician, 330; in time scale, 315 

 Organism, 92 

 Organization, 92, 93; in animals, 93; 



industrial, 92; internal, 108; in 



metazoa, 94 

 Organogeny, 224; in the vertebrates, 223- 



235 

 Organology, 114 

 Organs, 95; function of, 143; larval, 203; 



physiology of, 143; of special sense, 



163, 164 

 Origin of animals from mud, 165 

 Origin of mitotic spindle, 76 

 Origin of Species (Darwin), 22, 342 

 Oriole, Baltimore, range of, 292 

 Ornithologist, defined, 5, 267 

 Orthocone, suture of, 330 

 Orthogenesis, 360, 361, 362 

 Orthoptera, classified, 270 

 Osculum, 170 



Osmosis, 44, 45, 46, 57, 147 

 Osmotic pressxire, 44, 45, 46 

 Ostracoda, classified, 270 

 Otozoa, 263 



Ova, 128, 174; parthenogenetic, 182 

 Ovary, 128, 129, 236; of earthworm, 119; 



eggs fertilized in, 196; in lizard, 195 

 Over-growth, 221 

 Ovicells, 100, 101 

 Oviduct, 128, 129, 130; of earthworm, 



119; in lizard, 195; opening of, 128 

 Oviparit'- 195, 205; in aquatic animals, 



2v. in invertebrates, 198; locus and 



nutrition of embryo in, -95, 196; 



parental care in, 201; relation to 

 place of fertilization, 198; in verte- 

 brates, 198 



Oviposition (see Eggs) 



Ovisac, 128 



Ovoviviparity, 195; in lizard, 195; locus 

 and nutrition of embryo in, 195, 196, 

 197; relation to place of fertiliza- 

 tion, 198; in reptiles, 195 



Ovum, 174, 176, 180 



Owl, burrowing, range of, 292 



Oxalic acid, 59 



Oxidation, 68; of iron, forming red beds, 

 319; in muscles, 158; producing 

 light, 155; rate of, after fertiliza- 

 tion, 187. (See also Fats and Pro- 

 teins.) 



Oxygen, 50, 57, 58; in arterial blood, 149; 

 in capillaries, 150; carried in plasma, 

 149; combination with hemoglobin, 

 149; mechanism of collection and 

 transportation of, 148; in placenta, 

 195; requirement of animals, 148; 

 in venous blood, 149 



Oxyhemoglobin, 149 



Oxytricha, 66, 68 



Oysters, 173 



Pi, 243 



Pedogenesis, 181; bisexual, 181; parthe- 

 nogenetic, 181 



Pain, 161, 163 



Palaiomastodon, 319, 320, 321 



Paleobotany, 6, 310 



Paleontological evidence, 337 



Paleontology, 4, 6, 310-338; bearing on 

 relationship of living animals, 331 



Paleozoic, 319, 332; in time scale, 315 



Paleozoology, 310 



Palmitic acid, 52 



Palpigradi, classified, 270 



Pancreas, 118, 120, 146, 154, 227, 228; 

 secretion of, 153, 159; stimulation of, 

 144 



Pancreatic juice (see Pancreas) 



Pandorina, 87, 88, 90, 93 



Pandorina morum, 88, 89, 176 



Pangenesis, 342 



Fapilio philenor, food of, 281 



Paramecium, 61, 62, 66, 81, 85, 91, 93, 

 107, 172, 180; classified, 271; con- 

 jugation of, 178-180; reproduction 

 of, 190 



