836 



INDEX 



Stickleback, visual acuity of, 660 



See also Gasterosteus, Eucalia, Spinachia. 

 Stigma, 125 

 Stizostedion, visual acuity of, 657 



visual cells, 307 

 Stoneflies, 218 

 Strepsiptera, 220, 221 

 Streptopelia, 398, 681 

 Strigidse. See Owls. 

 Stringops, 418 



fovea, 418 



visual field, binocular, 685 

 Strix aluco, anterior chamber, 404 

 fundus, 410, PI. XII 

 head of, 402 

 visibility of infra-red to, 630 



fiamtnea, pecten, 412 

 Stroboscopic movement, 706 

 Strongylocentrotus, protection from light, 



39 

 .Struthio, 397, 405 



ciliary muscle, 406 



eye -shine, 405 



infula, 417 



pecten, 411, 413 

 Sturnus vulgaris, reproductive cycle in, 17 

 Stygicola, degenerate eyes in, 725 

 Stylaria lacustris, ocellus of, 136 

 Stylocheiron, 160 



eyes of, 160, 161 



luminous organ, 740 

 Stylophorus, 322 



tubular eyes of, 324 

 Stylophthalmus paradoxus, 328 



eyes of, 327 

 Stylops, 221 



eyes of, 151, 221, 734 

 Suboesophageal ganglion, in arthropods, 



521, 522 

 Subscleral sinus, in lamprey, 266 

 Suctorians, 179, 180 

 Suidae, 445 



See also Pig. 

 Sula bassana, 407 



area centralis, 421 

 ciliary muscle, 407 

 distance, judgment of, 703 

 sphincter muscle, 407 

 Summation, geniculate, 611 



retinal, 611 



visual acuity and, 659 

 Sun-navigation. See Light-compass 



reaction. 



Suoidea, 445 

 pupils, 472 



tapetum lacking, 458, 609 

 See also Pig, Hippopotamus, etc. 

 Superposition eye, 169, 174 

 Supplementary layer of cornea, 296 

 Supi"a- oesophageal ganglion. See 



Cerebral ganglion. 

 Supra-optic nucleus, 557 

 Suricate, 459 



diurnality of, 604 

 pupils, 472 



tapetum lacking, 459, 609 

 Suspensory ligament, of iris, 464 

 of lens, in chondrosteans, 317 

 in holosteans, 321 

 selachians, 285 

 teleosts, 302 

 urodeles, 347 

 See also Zonular fibres. 

 Sutures (lens), in birds, 409 

 in placentals, 474, 475 

 selachians, 287 

 teleosts, 304 

 Swallow, bifoveate retina in, 418 



See also Hirundo. 

 Swan, eye of, 399 

 Sweat glands, conjunctival, 491 

 Sycon, 181 



myo -epithelial cells, 513 

 Synapta, sensitivity of, 184 

 Synchceta, cerebral eye of, 194 

 Syngnathus, 309 



colour preference in, 624 

 fovea of, 309 



visual field, binocular, 680 

 Syrnium. See Strix. 



Tabanidse, eyes of, 225 



See also Tabanus, Ancala. 

 Tabanus, 219 



nervous system, 522 

 Tachyglossus. See Echidna. 

 Tactile sense, 116 



colour changes and, 105 

 in crustaceans, 579 

 Dytiscus, 104 

 fishes, 598 



cave-, 726 

 insects, 581 



