INDEX 



633 



O. ranarum, 7, 22, 99 



Opalinidae, see Prociliata 



Opening (Aperture), Atrial, see At- 

 rial opening; Excretory, see Ex- 

 cretory organs, Renal openings; 

 Genital, see Generative organs; 

 of Mantle cavity, see Mantle. See 

 also Anus, Mouth, Oscula, Ostia, 

 Pneumostome, Pores 



Operculum, 237 



Ophiocoma, 564 



Ophioglypha, 562 



Ophiopluteus, 556 



Ophiothrix, 564 



Ophiura, 562, 564 



Ophiuroidea, 562; 547 



Ophryocystis, 89 



O. mesnili, 90 



Opisthobranchiata, 492; 479, 493 



Opisthosoma, 271; 443, 448, 454, 

 456,458,465. See also M-esosovadi, 

 Metasoma 



Opisthoteuthis, 525; 513 



Optic lobes of Crustacea, 303 



Oral aspect (side, or surface), 124 ; of 

 Echinodermata, 547 



Oral cone, 129; 130, 135, 138 



Oral disc, 159 



Oral siphon, 592 



Oral valves, 578 



Ornithodorus moubata, 465 



Orthoceras, 524; 524, 528 



Orthoptera, 409 ; 388 



Oscarella, 1 19 



Oscula, of Porifera, no, 112, 113; of 

 Radiolaria, 71, 76 



Osphradia, 490, 492 



Ossicles, of Echinodermata, 550; 

 Adambulacral, 558; Ambulacral, 

 558, 562, 567; Basal, 579; Bra- 

 chial, 580; Centrodorsal, 578, 579; 

 Cirrhal, 580 ; Infero-marginal, 558 ; 

 of Holothuroidea, 572, 573 ; Pin- 

 nulary, 580; Radial, 580; Rosette, 

 579; Supero-marginal, 558. See 

 also Auriculae, Skeletal plates 



Ossicles, System of, in Asteroidea, 

 558 ; in Crinoidea, 579 ; in Echino- 

 idea (plates), 464; in Holothuro- 

 idea (calcareous ring), 573 ; in 

 Ophiuroidea, 562 



Ostia, 279; 112 



Ostracoda, 329; 291, 295, 297, 309, 

 3i4> 316 



Ostrea, 510; 504, 507 



O. edulis, 473, 510, 511 



Otocyst, see Statocysts 



Otoplana, 189 



Ova, see Eggs 



Ovarian lamella, 340 



Ovarioles, 397 



Ovary, see Generative organs 



Ovicell, 535 



Oviducts, see Generative organs 



Ovigerous frenum, 340 



Ovigerous legs, 466 



Ovipositor, of Insecta*, 387, 409, 



432 ; of Phalangida, 465 

 Ovotestis of Helix, 486 



Pachytylus migratorius, 410 



Paedogamy, 78 



Paedogenesis, 396 



Paired limbs, see Limbs 



Palaeonemertini, 208 



Palaeophonus, 452 



Palinura, 362 



Palinurus, 373 



Pallial arteries of Lamellibranchiata, 



505 



Pallial budding, 599 



Pallial circulation of Lamellibran- 

 chiata, 506 



Pallial gills, 490 



Pallial sinus, 540 



Palliovisceral cords, 474 



Palmella, 42 



Palolo worm, see Leodice viridis 



Palps, Labial, see Labial palps; 

 Mandibular, see Mandibular palps ; 

 of Acarina, see Pedipalps ; of Poly- 

 chaeta*, 231, 235 



Paludicola, 189 



Paludina, 492 ; 470, 478, 490 



P. vivipara, 478 



Pancreatic tissue, 518 



Pandalus, 300 



Pafidorina, 51 ; 40, 52 



Panorpa coniftiimis, 426 



Pansporoblasts, 93 



Panthalis, 233; 231 



Pantopoda, 466 



Papillae of mouth of Ascaris, 

 218 



Parabasal body, 1 1 



Paractinopoda, see Synaptida 



Paragaster, 1 1 o 



Paragnatha, 303 



