588 EMBRYOLOGY OF THE LOWER VERTEBRATES 



Neurenteric canal, 41, 51, 52, 53 

 Neurite, 84 

 Neurobiotaxis, 121 

 Neuroblasts, 84 

 Neurofibrils, 85, 112, 119 

 Neuroglia, 84 

 Neuromasts, 132 

 Neuromery, 101 

 Neurone, 84 



theory, 104 

 "Normal plates,'' 575 

 Notoehord, 147, 289 

 Nototrema, 463 

 Nuclear division, synchronism of, 16, 17, 22 



Odontoblasts, 322 

 Olfactory bulb, 91 



organ, 125 



tract or peduncle, 94 



tubercle, 91 

 Ontogeny, general principles, 484 

 Opaque area, 518 

 Operculum, 158 

 Opisthonephros, 221, 246 

 Optic cup, 134 



nerve, 140 



recess, 90 



thalamus, 89 

 Otocyst, 129 

 Ovary, 274 

 Overgrowth, 32 

 Oviduct (Mullerian duct), 242 



Palaeontology and Evolution, 502 

 Paludicola, larval jaws, 76 

 Pancreas, 189 



evolutionary origin, 191 

 Pander, nucleus of, 514 

 Panizza, foramen of, 391 

 Parachordal cartilages, 307 

 Paraphysis, 87 

 Parapineal body, 97 

 Pecten, 552 



Pectoral girdle, 354, 357 

 Pellucid area, 518 

 Pelvic girdle, 355, 358 

 Periblast, 23 



Pericardiac cavity, 200, 210 

 Pericardio-peritoneal canal, 200 

 Periderm, 70 

 Peripheral mesoderm, 63 

 Peritoneal canal, 226 



funnel, 226, 227, 251 



funnels, persistent, 251, 253 

 Peritoneum, 217 

 Petromyam (Lamprey) — 



arcualia, 294, 296, 299 



gastrulation, 37, 38 



horny teeth, 77 



liver, 187 



mesoderm segments of head, 211 



pericardiac cavity, 200 



pineal eyes, 99 



practical hints, 559 



Petromyzon (continued) — 



thyroid, 176 



tongue, 151 



veins, 416 

 Pharynx, 153 

 Phyllobates, 462 

 Phyllomedusa — 



early stages, 567, 568 



egg-laying, 459, 460 



lens, 139 

 Pigment, egg, 4 



skin, 80 

 Pigments, melanin, 81 

 Pineal body, 87, 96 



eye, 96, 97, 98, 99 

 Pinkus's organ, 133 

 Pipa, 461 



Pituitary body, 90, 142 

 Placenta, 465, 480 

 Placodes, nerve, 123 

 Planula, 506 

 Plasmodesms, 111 

 Platybasic, 307 

 Platyd.actyl.us — 



gastrular lip, 49 



gastrulation, 48, 50 

 Pleural cavity, 202 

 Plexus, choroid, 91 

 Pneumatic duct, 161 

 Poison-fangs, 326, 329 

 Polar cartilage, 313, 315 

 Polyptems — 



archinephric duct, 241 



blood-corpuscles, 365 



brain, 85, 95, 146 



cement-organs, 178, 179 



dorsal aorta, 363, 364, 365 



egg, 3 



external form, 430 



gastrulation, 19, 32, 33 



heart, 388 



limb-skeleton, 353 



lung, 169, 172, 173 



male genital duct, 281 



olfactory organ, 127, 128 



opisthonephros, 258 



oviduct, 278 



pancreas, 147, 189 



practical hints, 562 



pronephros, 228, 229 



sagittal sections, 146, 147 



scales, 336 



sclerotome, 285 



segmentation, 19 



size of egg, 2 



venous system, 416, 418 

 Polyspermy, 17 

 Postanal gut, 145, 147, 195 

 Postbranchial body, 178 

 Pouch, enterocoelic, 57 

 Primary cell-layers, 30 

 Primitive groove, 53 



plate, 48 



streak, 51, 53, 495, 497, 519, 520 



