838 



INDEX 



Teleosteans, refraction of, 638 

 secretory mechanism of, 267 

 tapetum, choroidal, 609 



retinal, 612 

 threshold to light, absolute, 616 



difference, 617 

 vision of, 598 

 visual acuity, 660 

 field, binocular, 679 



uniocular, 670, 672 

 pathways, 536 

 Telescope -eyed goldfish, 324 

 Telescopic eyes. See Tubular eyes. 

 Telo-menotaxis, 61 

 Telotaxis, 31, 55 



definition of, 43 

 Temperature, diiirnal rhythm in, 13 

 Tenacular ligament, ciliary, in birds, 405 

 in lacertilians, 357 

 orbital, in teleosts, 312 

 Tenebrio larvae, photokinesis in, 114 

 Tensor choroidese, in anurans, 335 

 in birds, 406 



teleosts, 295, 302, 646 

 Tentaculocysts, in jellyfish, 183 

 Termites, 218, 729 

 eyes lacking in, 729 

 See also Calotermes. 

 Terrapin, 374 



See also Clemmys, Chelonians, 

 Testudinidse, 369 

 Testudo, 369 



ciliary musculature, 372 

 colour vision in, 629 

 eye of, 370 

 visual cells, 373 



field, binocular, 682 

 Carolina, iris, 371 

 grceca, scleral ossicles, 369 

 Tetragonopterus, iris, PI. II 



scleral cartilage, 294 

 Tetraodon, fovea, 310 

 Thalamus, optic, 538 



Thalassarctos m-aritinius. See Bear, polar. 

 Thallophytes (unicellular plants), 510 

 Thaumatops magna, eyes of, 207 

 Thelotornis, fovea, 388, 392 



pupils, 388 

 Therapsida, 234, 236 

 Thermal sense of snakes, 599, 600, 667 

 Thermo -receptors, 116 

 Thermotropism, 33 

 Thigmotropism, 33 



Threshold to light, absolute, in insects, 

 584 

 in vertebrates, 616 

 binocular, 673 

 difference, in insects, 585 

 in vertebrates, 617 

 Thrips, 218, 220 

 Thrush, 402 



shape of eye, 402 

 Thunnus, 294 



scleral ossicles, 294 

 Thylacinus. See Tasmanian wolf. 

 Thysanoptera, 218, 220 

 Thysanura, 211, 218 



See also Lepisma. 

 Ticks, 216, 217 



eyes of, 216 

 Tiger (Felis tigris), 445 



area centralis, 485 



extra-ocular muscles, 495 



pupils, 471 

 Time -memory, in arthropods, 22 



in birds, 22 



diurnal rhythm in, 22 

 Tinamou, 397 

 Titmouse. See Par us. 

 Toad. See Bufo. 



clawed. See Xenopus. 



fire-bellied. See Bomhinator. 



obstetric. See Alytes. 



Svirinam. See Pipa. 

 Tomopteris, luminescence in, 745 

 Topotaxis, 31 



Tornaria of Balanoglossus, 227 

 Torpedo, 281 



accommodation in, 647 



blinded, behaviour of, 598 



cornea, 281 



electric organ of, 751 



pupil, 287 

 Tortoise, 372 



See also Che\onia,ns,, Testudo. 

 Toucan, ocular inovements of, 696 

 Touch. See Tactile sense. 

 Toxotes jaculator, 701 



spatial judgments of, 701 

 Tracheae, in compound eyes, 168 

 Trachinus, fovea, 310 



ocular movements, 693 

 Trachycephalus, pupils, 339 

 Trachysaurus, 682 



visual field, binocular, 682 

 Tragulina, 446 



