INDEX 



619 



Olfactory capsule, 39, 42, 436, 493 

 ,, lobe, 1 60, 460, 528 

 ,, organs : Frog, 180 ; Cray- 

 fish, 381 ; Mussel^ 409 ; Dogfish, 

 432, 464 ; Rabbit, 534 ; de- 

 velopment of, in Vertebrates, 587 



Olfactory pit, 424, 587 



Oligochseta, 350 



Ommatideum, 380 



Omosternum, 48 



Ontogeny, 224 



Oogenesis,i96, 568 



Oosperm, 198, 571 ; and see under 

 various types 



Oosperm, holoblastic and mero- 

 blastic, 573 



OPALINA : occurrence and general 

 characters, 280 ; nuclei, 280 ; 

 parasitic nutrition, 282 ; repro- 

 duction, 282 ; means of dispersal, 

 283 ; development, 283 ; practical 

 directions, 293 



Optical section, 558 



Optic chiasma, see Chiasma ; cup, 

 588; lobe, 157, 459, 530, 584; 

 thalamus, 159, 529; vesicle, 587 



Oral cavity, see Buccal cavity 



Oral hood, 421 



Orbit, see Skull 



Order, 218 



Organ, 30, 151, 238, 344 



Organism, 231 



Origin of muscles, 60 

 ,, of species, 225 



Osmosis, see Diffusion 



Osphradium, 409 



Ossicles : of gizzard (Crayfish], 372, 

 390 ; auditory (Rabbit], see Audi- 

 tory ossicles 



Ossification, 44 



Ostia : of heart, 376 ; of gills, 404 



Otocyst, 315, 409 



Otoliths, 1 88, 382 



Ovary : Frog, 23, 193, 195 ; and see 

 Reproductive organs 



Oviduct, 25, 196, 346, 382, 469, 



540, 594 

 Ovisac, 195, 540 

 Ovum, 195, 563, 568, 572 ; and see 



under various types. 



Ovum : alecithal, centrolecithal, and 



telolecithal, 573 

 Oxidation of protoplasm, 149, 248 



X abeontology, 224 



Palate, 494, 507 



Palatoquadrate, 44, 438 



Pallial line, 399 



Pallium, see Mantle 



Palp : Nereis, 351 ; Crayfish, 367 ; 



Mussel, 401 

 Pancreas, 22, 70, 134, 204, 447, 



5i6, 589 



Pancreatic juice, 70 

 Papillae of tongue, 1 80, 509 

 Parachordal, 595 

 Paragnatha, 370 

 Paramylum, 251 



PARAMCECIUM : structure, 262 ; 

 mode of feeding, 266 ; reproduc- 

 tion, 268 ; conjugation, 268 ; 

 practical directions, 277 

 Parapod, 350 

 Parasite, parasitism, 33, 153, 280, 



284 

 Parietal layer of peritoneum, 26, 



331 ; see also Mesoderm 

 Parthenogenesis, 569 

 Patella, 504 



Pectoral arch, 20, 36, 46, 442, 500 

 ,, fin or limb, see Appendages 

 Pedal ganglion, 408 

 Pelecypoda, 411 

 Pelvic arch, 20, 36, 50, 442, 503 



,, fin or limb, see Appendages 

 Pelvis of kidney, 538 

 Penis, 487, 540 

 Pepsin, peptone, 74 

 Pericardial gland, 406 

 Pericardial sinus, 376 

 Pericardium, 20, 401, 434, 520 

 Perichondrium, 55 

 Perilymph, 189 

 Perinaeum, 486 

 Periosteum, 55 

 Periostracum, 399 



