INDEX 



839 



Training techniques, 569 



colour vision and, 624 

 Transversalis inuscle. in chelonians, 372 

 in lacertilians, 357 



pigeon, 407 

 function of, 651 

 Tree-frog. See Hyla. 

 Tree-shrew, See Shrew, tree- 

 Tree-snakes, accommodation in, 648 

 fovea, 392 



ocular movements of, 695 

 pupils, 388 

 visual acuity of, 661 

 field, 675 

 Trematodes, 187 



sense organs of, 189, 734 

 Triakis, pupil, 286 

 Tricheclnis. See Manatee. 

 Trichomonads, 179, 180 

 Trichoptera, 219, 220 

 Triclad worms, 187 

 eyes of, 188 



See also Planar ians, Dendrocoelum. 

 Trigla, visual field, binocular, 679 

 Trilobite, 157 

 eyes of, 157 

 Trinoton aculeatum, eyes of, 221 

 Triommatidion in aphids, 225 

 Triops. See Apus. 



Tristomum papillosurn, ocellus of, 130, 189 

 Tritocerebrum, in arthropods, 521 

 Tritiirits {Triton), 334, 346 



cartilaginous plaqvies, 347 

 colour vision in, 628 

 eyes of, 346, 728 

 iris vascularization, 347 

 retina, 347, 348 

 visual acuity of, 661 

 cristatus, 347 



colour changes in, 92 

 pyrrhogaster, iris, 347 

 torosus, u-is, 347, 371, PI. IV 

 Troglichthys, degenerate eyes in, 726 

 Troihis, colour blindness of, 587 

 Tropidonotus fasciatus, optic disc, 390 

 natrix natrix, 384 

 chiasma, 392 

 ciliary region, 388 

 colour training, 628 

 pupils, 388 

 retina, 389 

 visual cells, 391 



field, binocular, 684 



Tropidonotus tessellatus, accommodation, 



649 

 Tropo-menotaxis, 61, 68 

 Tropotaxis, 31, 52 



definition of, 43 

 Trout. See Salmo trutta. 

 Trygon, 285 



iris, 285 



pupils, 287 

 Trygonorhina, pupils, 286, 287 

 Trypanosoma, 179, 180 

 Trypauchen, degenerate ej^es in, 726 

 Trypauchenophrys, degenerate eyes in, 726 

 Tuatara. See Sphenodon. 

 Tuber nuclei of hypothalamus, 559 

 Tubular eyes, in cephalopods, 203 

 in fishes, 322, 323, 606 



by artificial selection, 324 

 optics of, 642, 643 

 visual field of, 675, 680 

 Tubulidentata, 445 



See also Aard-vark. 

 Tunicates, 228 



See also Ascidians. 

 Tunny. See Thunnus. 

 Tupaia. See Shrew, tree. 

 Tupinamhis, ciliary region, 358 



nigropunctatus , iris, PI V 

 Turbellarian worms, 187 

 dermal sensitivity, 114 

 nerve-net, 516, 518 

 nervous system, 518, 519 

 sense organs, 188 

 See also Planarians, etc. 

 Turdus migratorius, retinal summation in, 



660 

 Tvirkey, nictitating membrane, 423 



See also Meleagris. 

 Turris, sense organs of, 183 

 Tui-tle, 369 



See also Chelonians, Chrysemys, Emys, 

 etc. ^'' 

 Tylopoda, 446 



corpora nigra, 470 



pupils, 472 



tapetum lacking, 458, 609 

 Typhlachirus, degenerate eyes in, 726 

 Typldceontias, secondary spectacle, 367 

 TypMias, degenerate eyes in, 725 

 Typhlichthys, degenerate eyes in, 726 

 Typidocirolana, degenerate eyes in, 725 

 Typhlogobius calif orniensis, degenerate 



eyes in, 726 



