1 102 



INDEX 



Nodularia, in 



Nostoc, no; commune, no 



Nostoceae, no 



Nostochopsis, 113; lobata, 113 



Notaspis, 874 



Noteus, 605; quadricornis, 605 



Notholca, 603; longispina, 603 



Notocotylidae, 382 



Notocotylus, 383; quinqueserialis, 383 



Notodromas, 808; monacha, 798, 808 



Notommata, 591; aurila, 591, torulosia, 591, 



truncata, 556, 591 

 Notommatida, 587 

 Notommatidae, 587 

 Notommatina, 587 

 Notonecta, 934 

 Notonectidae, 934 

 Notops, 601; brachionus, 601, clavulatus, 601, 



Pelagicus, 60 1 

 Notopsidae, 569, 599 

 Notosolenus, 257; orbicularis, 257 

 Notostraca, 671 

 Nuclearia, 233; simplex, 233 

 Nudocotyle novicia, 383 

 Nuphar, 193 

 Nupharetum, 196 



Nylandera, 171; tentaculata, 171 ; 

 Nymphula, 903 



Obliquaria, 1014; reflexa, 1014 



Obovaria, 1012; ellipsis, 1013, retusa, 1013; 

 s. s., 1013 



Oceanology, i ; pelagic region, 4 



Ochromonas, 260 



Octhebius (adult), 938 



Octobothrium sagiltatum, 375 



Octocotylidae, 375 



Octotrocha, 615; speciosa, 615 



Odonata (damselflies, dragonflies), Fresh- 

 Water, 889-893, 917, 922-932; damselfly 

 nymphs, 89 1 , keys, 917; dragonflies (images) , 

 922-927, (nymphs), 928-932; see Insecta 



Odontalona, 720 



Odontidium, 132; mutabile, 132, tabellaria, 132 



Odontoceridae, 936 



Odors, cause of, 1073, observation of, 1072 



Oecistes, 615; brevis, 615 



Oedogoniaceae, 167 



Oedogonium, 167; crenulato-costatum, 167 



Oikomonas, 244; steinii, 244 



Oligobdella bianmdala, 654 



Oligochaeta (earthworms), Fresh- Water, 633- 

 645; biology, 635, excretory organs, 633, 

 key, 638-644, locomotion, 636, methods of 

 study, 636, occurrence, 632, references, 

 645, reproduction, 634, structure, 633; see 

 Chaetopoda 



Oligorchis, 441 



Olisthanella, 349; caeca, 349 



Olisthanellini, 349 



Oncholaimellus, 487; heterurus, 487 



Oncholaimus, 487, punctatus, 487 



Onchosphere, 427 



Onychodromopsis flexilis, 289 



Onychodromus, 289; grandis, 289 



Onychonema, 136; laeve, 136 



Onychopoda, 738 



Oocardium, 141; stratum, 141 



Oocystis, 151; solitaria, 151 



Oogonium, 119 



Oospore, 119 



Open- water collecting; see Methods of Collect- 

 ing 



Opercularia, 295; plicatilis, 295 



Ophidonais, 639; serpentina, 639 



Ophiocytium, 157; cochleare, 157 



Ophiogomphus (imago), 924, (nymph), 929 



Ophiotaenia, 438; filaroides, 425, 438, grandis, 

 439, lonnbergii, 438, perspicua, 439 



Ophridinopsis, 296 



Ophrydium, 296; eichhornii, 296 



Ophryocotyle, 441; proteus, 441 



Ophryoglena, 278; air a, 278 



Ophryoxus, 708; gracilis, 708 



Opisthodon, 276 



Opisthorchiidae, 393 



Opisthorchis, 393; pseudofelineus, 393 



Opisthotricha, 289 



Opistomum, 340 



Organisms, water; effect of pressure, 34, en- 

 vironment, 9, fluctuations, 54 



Orchestiidae, 843 



Oribatidae, 874 



Ornatae, cercariae, 419 



Orthocladius (larva), 945 



Orthorrhapha (larva), 943 



Orthosira, 126; orichalcea, 126 



Oscillatoria, 108; limosa, 108, prolifica, 108 



Oscillatoriceae, 107 



Osphranticum labronectum, 774 



Ostracoda, 790-827; development, 797, dis- 

 tribution, 801, genital organs, 795, key, 

 806-827, methods of study, 803, occur- 

 rence, 799, references, 827, structure, 791; 

 see Crustacea 



Ovatella, 979 



Oxus, 868; ovalis, 868, strigatus, 868 



Oxytricha, 289; pellionella, 289 



Oxyurella, 720, 722; longicaudis, 721, tenui- 

 caudis, 720 



Oxyuridae, 533 



Oxyuris dubia, 533 



Pachydiplax (imago), 927, (nymph), 932; 



longipennis, 890 

 Palaemon, 845; ohionis, 845 

 Palaemonetes, 845; exilipes, 845, paludosa, 



845, wdgaris, 845 

 Palaemonias ganteri, 845 

 Palaemonidae, 845 



