INDEX 



827 



Prosimians, nocturnal, 604 



optic axis, 688 



orbit, 498 



pupils, 472, 612 



tapetum cellulosum, 459 



See also Lemurs, Tarsier. 

 Prosobranchs, 196 



neuro -secretory cells, 552 



See also Buccinum, Patella, etc. 

 Proteus anguinus, 334, 726 

 eyes of, 727, 728 

 pineal organ, 714 

 retina, 728 

 Protocerebrum, in arthropods, 521 

 Protochordates, 227 



eyes of, 227 



luminous organs, 740 



nervous system, 530 



neuro -endocrine system, 552 



See also Balanoglossus, Atnphio.vus, 

 Ascidia. 

 Protopterus, 312 



eyes of, 312 

 Prototheria. See Monotremes. 

 Protozoa, 179, 180, 510 



bioluminescence in, 738 



contraction in light, 7 



eye-spots, 125 



intercellular fibrils, 511, 512 



reproductive cycle of, 16 



tropisms in, 570 



See also Amoeba, Euglena, etc. 

 Protractor lentis muscle, in anurans, 336. 

 648 

 in selachians, 285 

 Protura, 217, 218 



eyes lacking in, 729 

 Psephurus, 315 

 Psettodes, 329 



migratory eyes in. 329 

 Pseudocone eye, 167 

 Pseudomoyias lucifera, luminescence of, 



738 

 Pseudoscorpions, 214, 215 



eyes of, 214 

 Psocoptera, 218, 220 

 Psylla, reproductive cycle in, 17 

 Ptarmigan (Lagopus mutus), coloiu" 



changes in, 21 

 Pier as pis, 234 



eyes of, 238 



pineal organ of, 713 



Pterocera lamhis, 198 



ocelli of, 142, 197 

 Pterois, iris, 371 

 Pteromys. See Flying squirrel. 

 Pteropus. See Flying fox. 

 Pterotrachea, accommodation in, 590 



eyes of, 199 

 Pterygotus anglicus, 157 



eyes of, 157 

 Ptychodera, kiminescence in, 740 



rhythmic, 22, 747 

 Pufflnus puffiniis, 407 

 iris, 408 



navigation by, 63, 64 

 retina, 417 



sphincter muscle, 407 

 Pulex irritans, 219 

 Pulmonates, 196 

 eyes of, 197 

 nervous system, 528 

 See also Helix, Limax, etc. 

 Pulvinar, 542 

 Pupil, characteristics in 

 anurans, 339 

 birds, 408 

 chelonians, 372 

 chimferas, 290 

 chondrosteans, 317 

 crocodilians, 376 

 holosteans, 322 

 lacertilians, 359 

 marsupials, 439 

 yeoceratodus, 313 

 placentals, 470, 471, 613 

 selachians, 286 

 snakes, 388 

 Sphenodon, 381 

 teleosteans, 303, 304 

 urodeles, 347 

 contractile, occurrence of, 612 

 double, in Anableps, 324 



in Leptognathus, 325 

 stenopceic, 612, 641 

 Pupillary reactions, colour vision and, 621 

 consensual, 700 

 in amphibians. 339 

 birds, 408 



cejahalopods, 146, 575 

 crocodilians, 376 

 lacertilians, 361 

 placentals, 472 

 teleosts, 304 

 Purkinje shift, colour vision and, 622 



