808 



INDEX 



Hyracoidea, 446 



See also Hyrax. 

 Hyrax (coney), 444, 446 



diurnality of, 604 



retinal vascularization, 480 



umbraculum, 469, 470 

 Hystricomorpha, 445 



See also Porcupine, Chinchilla, Guinea- 

 pig, etc. 

 Hystrix. See Porcupine. 



Ichthyomyzon, 260 



visual cells of, 269 ' - 



Ichthyophis, 730 



degenerate eyes in, 730 

 Ichthyopsida. See Fishes and Amphi- 

 bians. 

 Idiacanthus fasciola, 328 



larva. See Stylophthalmus . 

 Idotea, colour changes, rhythmic, in, 20 

 Iguana, 355 



accommodation in, 651 

 parietal eye, 715 

 visual field, binocular, 682 

 tuherculata, 358 

 iris, 358 



furrow, 337 

 Impennes (Sphenisciformes), 397, 398 

 ocular adnexa, 425 

 movements, 696 

 refraction, 639, 654 

 See also Eudyptes, Spheniscus. 

 " Imprinting " in birds, 704 

 Indris, diurnality of, 604 

 Infra-red rays, sensitivity to in vipers, 

 117, 600 

 visibility of, in owls, 620, 630 

 Infula, in retina of birds, 417 

 Infundibular organ, of Amphioxus, 229 

 Infundibulum, 538 



Vesalius's drawing of, 549 

 Insectivores, 441 

 brain, 533 

 cerebral cortex, 543 

 ciliary region, 460 

 colour vision in, 633 

 diurnal, 604 

 degenerate eyes in, 733 

 nictitating membrane, 493 

 ocular movements of, 696 



Insectivores, optic axis, 688 

 retinal vascularization, 479 

 vision of, 601 

 See also Mole, Shrew, etc. 

 Insects, 217 



accommodation in, 591 

 bioluminescence in, 740, 746 



rhythmic, 22 

 blind, 722, 729, 734 

 cerebral ganglion, 521 



removal of, 525 

 chromatophores, 86 

 colour changes in, 82, 93 

 control of, 555 

 rhythmic, 20 

 vision in, 586 

 dermal sensitivity in, 114 

 eyes of, compound, 166, 224 



simple, 224 

 inactivity in light, 7 

 larvae of, nervous system, 519 

 ocelli, 222 

 vision of, 582 



See also Caterpillar, Maggot, 

 luminous organs, 742, 746, 747 

 metabolic rhythms in, 15 



control of, 556 

 nervous system, 521, 522 

 neuro -endocrine system, 552, 555, 556 

 ommochromes in, 123 

 orientation of, out-of-doors, 67 

 reproductive cycle of, 17 



control of, 556 

 retinal pigment migration in, 170 

 control of, 556 

 rhythmic, 19 

 time-memory in, 22 

 vision of, 581 

 visual acuity of, 588 

 centres in, 524, 525 

 pigments in, 121 

 Instincts, 108 

 Integumentary pigment. See Pigment, 



integumentary. 

 Interocular transfer of impressions, 698 

 Intra-ocular filters, 656 



pressvire. See Ocular tension. 

 Intrascleral plexus. See Circle of Hovius 



and Canal of Schlemm. 

 Invertebrates, accommodation in, 590 

 eyes of, degenerate, 722, 724, 728, 733 

 morphology, 113 

 systematic anatomy, 178 



