INDEX 



583 



Ocean, bio tic divisions, 176 

 physical conditions in, 150 

 the most extensive habitat, 146 

 Ocean currents, 59, 153, 243, 244 

 Oceanic islands, 516 

 Oceanic pelagial, 241 

 Oceanodroma castro, 486 

 Oceans, continuity, 146 

 Ochotona dauricus, 457 

 Ochrida, Lake, 87, 345, 347 

 Ochlhebius, 373 

 Octopus, 200 

 Ocydromus, 521 

 Ocypoda, 196 

 Odhner, 162 36 

 Odocoileus, 388 

 0. bezoarticus, 444 

 O. mexicanus, 388 

 Odynerus, 88 

 Oecophylla, 109, 431 

 Oedipus, 403 



zonal distribution, 495 

 Oeneis, 508 



Oesting and Allee, 55 18 

 Oestrelata hypok'uca, 486 

 Oikomonas, 550 

 Oikopleura albicans, 237 

 O. dioica, 166, 244 

 O. labradoriensis, 153, 244 

 Oja-shio, 171 

 Oligotrophic lakes, 344 

 Olofsson, 376 19 

 Ommastrephes, 253 

 Oncorhynchus, 317 

 0. keta, 318 



Ondatra rivalicu-s, 478 



Onychiurus sibiricus, 537 



Ooze, oceanic, 154, 250, 266 



Open country, environmental factors, 443 



Ophiocten sericeum, 279 



Ophioglypha albida, 192, 193 



O. robusta, 193 



O. sarsii, 194 



0. texturata, 192 



Ophiura ciliaris, 195 



Opisthocomus, 426 



Optimum conditions, 145 

 deviation from, 23 



Orbulina universa, 224 



Orchards, rich in species, 544 



Orchestia, 42, 196, 524 



O. bottae, 524 



O. chevreuxi, 524 



Orchomenopsis chilensis, 278 



Oreamnos, 503 



Oreotrochilus chimborazo chimborazo, 125 



Organic content in inland waters, 291 



Organs of hearing, 52 



Origin of life placed in the sea, 12 



Orinodromus, 91 



Oriolus oriolus kundoo, 388 



O. oriolus oriolus, 388 



Ornithorhynchus, 94, 126 



Orostygia, 533 



Orthoptera, of the alpine zone, 498 



of steppes, 459 



steppe relicts, 102 



warmth-limited, 382 

 Ortmann, 95 6 , 222 62 - <*■ «, 247", 269 2 ', 



271, 279, 286>- 4 , 287 39 - « 

 Orycteropus, 403, 460 

 Orycus, 530 



Osgood, Preble and Parker, 489 13 

 Osmerus eperlanus, 39 

 Osmotic pressure, 165 



in aquatic animals, 35 

 Osten-Sacken, 468 89 

 Ostenfeld and Wesenberg-Lund, 357 37 , 



376 20 

 Ostrea edulis, 158, 197, 205 

 O. glomerata, 205, 206 

 0. mytiloides, 197 

 Otaria, 412 



Otomesostoma auditivum, 364 

 Overton, 35, 55 7 



Oyster-banks in the North Sea, 206 

 Oysters in estuaries, 197 

 Oxygen, 173 



an environmental factor, 18 

 Oxygen content, 174 



in seas, 280 

 Oxygen-deficiency in lakes, 334 

 Oxygen-tension, 292 

 Oxygenation in lakes, 325 

 Oxygyrus keraudreni, 238 



Pachylasma giganteum, 283 

 Pachytylus migratorius, 381 

 Pacific, poverty of southeastern, 172 

 Pagenstecher, 134 2 - 2 °. 45 , 504 28 , 514 1 " 



