328 



THE ELASMOBRANCH FISHES 



Palatine nerve, 224, 243 



Palatoquadrate cartilage, 45, 62 ; muscles 

 to, 90 



Pallial eminence, 221, 232 



Pancreas, 124, 138; arteries to, 166; duct 

 of, 124, 138; lobes of, 124, 138 



Pancreatic duct, 124, 138 



Papillae of oesophagus, 134 



Paracentral mass, 237 



Parachordal plates, 53 



Paraphysial arch, 233 



Paraphysis, 233 



Parietal fossa, 43, 55, 271 



Pectoral fin, 6, 12; arteries to, 168, 191; 

 function of, 12, 13, 14; fusion of, to 

 sides in rays, 12; muscles of, 89, 94; 

 nerves of, 227, 246-247; veins of, 202, 

 213 



Pectoral girdle, 49, 79-81; development 

 of, 77; muscles to, 89; parts of, 49, 79- 

 81 



Pectoral muscles, 89, 94; development of, 

 110 



Pectoral plexus, 227, 246 



Pelagic, 1 



Pelvic fin, 6, 14; claspers of male on, 6 



Pelvic girdle, 6, 51, 82, 228; origin of, 82 



Pelvic plexus, 228, 247 



Pentanchid types, 150 



Pepsin, 135 



Peptic cells, 135 



Pericardial artery, 163, 179 



Pericardial cavity, 151, 171 



Pericardio-peritoneal septum, 287 



Perimeningeal space, 237 



Peripheral nervous system, 223-228, 238- 

 248; development of, 238 



Pharyngeal nerve (IX), 225, 244; (X), 

 225-227, 245 



Pharyngobranchial cartilages, 46, 64; fu- 

 sion of, in last arch, 65; muscles of, 

 92, 106-107 



Pharynx, 122, 131-134; lining of, 132; 

 muscles of, 90-93, 101-108; perfora- 

 tions of, 122, 131; stomodeal denticles 

 in, 122 



Photogenic cell, 29 



Photophore, 29 



Pigment, 23, 27, 29, 33; function of, 27 



Pineal stalk, 221, 233, 236; development 

 of, 233 



Pit organs, 262, 274, 281-282; nerves to, 

 225, 244, 282 



Pituitary, 221, 233 



Placodes, 264 



Placoid scales, 7, 30-32; absence of, 32, 

 309; base of, 24, 32; canals of, 30, 32; 

 development of, 30 ; finer anatomy of, 

 32; modified, 24-25, 33, 154; spines of, 

 32,33 



Plasma, 170 



Plenr acanthus, 1 



Poison gland of ray, 28 



Pori abdominales. See Abdominal pores 



Portal vein. See Hepatic portal 



Portio major (V), 240 



Portio minor (V), 240 



Postbranchial body, 151 



Postcardinal sinus, 200, 204, 210; in rays, 

 210; relation of, to subscapular vein, 

 214 



Postcardinal vein, 200, 204, 210; tribu- 

 taries of, 200, 210 



Posterior cerebral artery, 165, 184 



Posterior cerebral vein, 207 



Posterior commissure, 233 



Posterior coronary artery, 168, 179, 192 



Posterior dorsolateral artery, 168 



Posterior efferent-collector artery, 176 



Posterior gastro-pancreaticosplenic artery, 

 166, 188 



Posterior gastro-pancreaticosplenic vein, 

 211 



Posterior gastrosplenic artery, 166, 188 



Posterior intestinal artery, 167, 188, 190; 

 in rays, 190 



Posterior intestinal vein, 200, 211 ; tribu- 

 taries of, 200 



Posterior mesenteric artery. See Inferior 

 mesenteric 



Posterior oblique semicircular canal, 259, 

 261,273 



Posterior (outer) buccal ampullae, 262, 

 279 



Posterior rectus muscle. See External rec- 

 tus 



Posterior thyroid artery, 164 



Postorbital groove, 205 



Postorbital process, 43, 44, 45, 58, 60 ; in 

 ChJainydoselachus, 58; in notidanids, 

 58 ; in rays, 58 



Post-trematicus nerve (IX), 225, 244; 

 (X),225, 245 



Postvelar arch, 233 



Premandibular somite, 99 



Preorbital process, 44, 58 ; in Zygaena, 58 



Prespiracular ligament, 63 



Prespiracular nerves, 224, 243 



