806 



INDEX 



Helix 



eyes of, 142, 197 

 menotaxis in, 61 



aspersa, 198 

 eyes of, 197 



pomatia, ocellus of, 142 

 visual cell, 128 

 Heloderma, 359 



ocular movements of, 694 



pupils, 359 



retina, 365 



visual cells, 364 

 Helophiliis, 141 



ocellus of, 140, 141 

 Hemichordata, 227 



eyes of, 227 



luminous organs in, 740 



nervous system, 530 



See also Balanoglossus . 

 Hemichromis himaculatus, colour reactions, 



627 

 Hemidactylus, 629 



colour vision in, 629 



turcicus, fundus, PI. VI 

 Hetnimysis, telotaxis in, 58 

 Hemiptera, 218, 220 



accommodation, static, in, 591 



eyes of, 167, 222, 224 



luminous organs of, 740 



nervous system, 521, 522 



neuro -secretory cells, 555 



See also Notonecta, Aphis, etc. 

 Hen. See Gallus domesticus. 

 Herons, binocular vision, 675 



See also Ardea, Nycticorax. 

 Herpestes. See Mongoose, 

 von Hess, Carl, 596, 597 

 Hesse, Richard, 112, 113 



organs of, 230 

 Heterauxin, 41 

 Heterodon jnodagascariensis, fundus, PI. X 



pupils, 388 

 Heterodontus, 286 



pupil of, 286 

 Heteropods, 199 



See also Pterotrachea, etc. 

 Heteroteuthis, biokiminescence in, 742 

 Hind-brain, 532, 533 

 lliodon, visual cells of, 305 

 Hippocampus, 310 

 fovea of, 309, 310 

 ocular movements, 693 



Hippolyte varians, 91 



colour changes in, 91 

 rhythmic, 20 

 Hippopotamus, 445 

 cilia lacking, 492 

 cornea, 453 

 eyelids, 491 



lacrimal passages lacking, 494 

 ocular adnexa, 501 

 optic axis, 688 

 visual acuity of, 654 

 Hirudinea, 190 

 Hirudo medicinalis, 193 



ocelli of, 133, 193 

 Hirundo rustica, 414 



binocular vision, 683, 684 

 colour vision in, 631 

 foveae, 421 

 pecten, 413, 414 

 Holangiotic retina, 479 

 Holocephalians, 235, 278 

 accommodation in, 647 

 eyes of, 290 

 pineal organ, 713 

 Holosteans, 235, 279, 321 

 accominodation, 640, 647 

 diurnality of, 603 

 eyes of, 321 



See also Amia, Lepklosteus. 

 Holothuria, 185 

 pigments in, 117 

 surinamensis, sensitivity of, 184 

 Holothuroidea, 184 

 sensitivity of, 184 

 Homalopsinge, accommodation in, 649 

 Homarus, 206 



colour changes in, 95 

 eyes of, 164, 206 

 vision of, 578 

 Homing, in ants, 68 

 birds, 63, 703 

 molluscs, 575 

 wasps, 78 

 pigeon, 64 



hue discrimination in, 619 

 navigation by, 64 

 visual acuity of, 665 

 Homochromatism, 83 

 Honey guides, 588 

 Hormonal system, 547 



See also Nevu'o -endocrine system. 

 Hormones, 549 



biokiminescence and, 22 



