INDEX 



805 



Grua, iris, 408 



ocular movements, 696 

 Guanine, 89, 608 



in integument, 89 



invertebrate eyes. See. Tapetum. 

 vertebrate eyes. See Argentea, 

 Tapetum. 

 Guanophores, 89 

 Guinea-pig {Cavia porcellus), 445 



colour vision of, 633 



cornea, 453 



epithelium of, 452 



gonadotrophic hormone, control of, 559 



ii'is, 467 



lacrimal passages, 494 



pineal organ, 716 



refraction of, 639 



retina, rod-rich, 610 

 vascularization of, 480 



threshold to light, difference, 618 



visual cells, 483 



field, uniocular, 672 

 Gulls, herring-. See Larus argentatus. 



navigation by, 64 



ocular movements in, 696 



retina, 419 



sphincter muscle, 407 

 Gulo. See Wolverine. 

 Guppy. See Lehistes. 

 Gurnard. See Trigla. 

 Gymnophiona. See Apoda. 

 Gymnothorax, pupil of, 304 

 Gymnura, brain, 533 

 Gyrinid beetle. See Whirligig beetle. 



H 



Habituation, to light stimuli, 36 

 Hcemadipsa, 190 



ocelli of, 134 

 Hcemopis, ocelli of, 193 

 Hagfishes, 259 



See also Myxiyie. 

 Haideotritoyi, degenerate eyes in, 728 

 Haliaetus, 410 



fundus, 410 

 Halicore. See Dugong. 

 Haliotis, ocellus of, 137, 139 

 Haller's ratio, 401, 450 

 Hangnest. See Cacicus. 

 Hapalemur, diurnality of, 604 



Harder's gland, 345, 494 

 characteristics in 

 anurans, 345 

 birds, 425 

 chelonians, 375 

 crocodilians, 378 

 lacertilians, 367 

 marsupials, 441 

 monotremes, 437 

 placentals, 494 

 snakes, 393 

 Sphenodon, 383 

 Hare (true), 445 

 cornea, 453 



nictitating membrane, 493 

 optic axis, 688 

 calling, 445 



diurnality of, 604 

 jumping, pupils, 612 

 varying, coloiu" changes in, 21 

 control of, 560 

 pupils, 471 

 Harvestman, 215 



eyes of, 215 

 Harvey, E. Newton, 736 

 Hatchet -fish. See Argyropelecus . 

 Hatter ia. See Sphenodon. 

 Hawks, 417 



accommodation, 651 

 distance, judgment of, 702 

 foveae, 417, 659 

 lens, 409 



scleral cartilaginous cup, 403 

 visual acuity, 662 

 field, binocular, 684 

 trident, 684 

 See also Accipiter, Buteo. 

 Hearing. See Auditory sense. 

 Hedgehog, 441, 442 

 colour vision in, 633 

 eyelids, 491 

 fundus, PI. XV 

 optic disc, 486 

 retina, pvu'e-rod, 610 



vascularization of, 479, 481 

 visual cells, 482 

 Helianthus (sunflower), phototropism in, 



41 

 Heliodrilus, conditioning in, 573 

 Heliophags, 123 

 Heliotropism, 38 

 Helix, 142 



circus movements in, 54 



