762 



INDEX AND GLOSSARY 



optic nerve (see also conus papillaris, pecten, 

 summation ) 

 branching of, 367, 589, 606 

 chiasma of (see optic chiasma) 

 head of 



blind spot created by, 1 78- 1 79 

 elongated, 179-180,576 

 eyeshine from, 230 

 multiple, 367, 589, 606 

 nerve-impulses in (see also retina, photo- 

 electric phenomena of), 80, 90-91, 

 103 

 proportion of decussation of, 319-320 

 taxonomically: 

 lampreys, 559-560 

 elasmobranchs, 569 

 sturgeon, 570 

 holosteans, 576 

 teleosts, 179, 261 

 cladistians, 589 

 dipnoans, 590, 632 

 cascilians, 606 

 crocodilians, 620 

 Sphenodon, 620 

 lizards, 632 

 snakes, 632, 635 

 birds, 643 

 mammals 

 monotremes, 666, 670 

 squirrels, 180, 367 

 whale, 413 

 seals, 445 

 man, 47, 51-52 

 optic pedicel, 564*, 564-565 

 optic radiations: the masses of geniculocor- 

 tical fibers— i.e., those which con- 

 nect the lateral geniculate bodies 

 with the visual cortex; 335, 337 

 optic tectum, 521*-522 

 optic tracts, 47, 52, 319*, 334-335, 521 

 optic vesicle, 105*, 105-106, 107-108 

 optical density, 22* -23 



optomotor (optokinetic) reaction, 301*-302, 

 310 

 and study of vision, 492-493 

 Orbeli, 506, 692 (entry for p. 506) 

 orbit, taxonomically: 

 lampreys, 556-558, 557 

 elasmobranchs, 564-565 

 sturgeons, 569 

 teleosts, 578 



electric organ in, 293 

 anurans, 594 

 CEecilians, 605 

 birds, 642, 650 

 man, 36, 39 

 Orcinus (mammal: killer whale), alleged 

 spying through air by, 411 



Orectolobus (elasmobranch: a shark), 



pupil of, 222 

 origin of eye, 119-133 



orimentary: said of structures which seem to 

 have appeared in evolution before 

 there was any real use for them, 

 and which became useful only to 

 later, descendant, groups of animals 

 Ornithorhynchus (mammal: duck-bill; 

 habits of, 201, 443 [platypus) 



ocular structure in, 664-671 

 pupil of, 221 

 relationships of, 138, 663 

 upward tilt of eyes in, 296 

 visual cells in, 59, 201, 670-671, 675 

 oil-droplets of, 692 (entry for p. 203) 

 Orycteropus (mammal: aard-vark) 

 ciliary body of, 679 

 cornea in 



cornification of, 665 

 ovoid form of, 679 

 eyeshine and tapetum lucidum in, 241 

 nictitating membrane of, 426 

 optic axes of, 297 ('edentates') 

 pectinate ligament of, 680 

 size of eye in, 677 

 taxonomic prosition of, 676 

 Osawa, 617-619 

 Osbom, 530 



osculant: said of a species or group related 

 to two others which it directly con- 

 nects — a living link as opposed to 

 a 'missing' {i.e., extinct) one 

 osmosis, 369-373*, 425, 529 

 Osphranter (mammal: a kangaroo), lens 



size and shape in, 674 

 osprey, feeding method of, 439 

 ostrich: Struthio, q.v. (American: Rhea, q.v.) 

 Otaria (mammal: sea lion), eye of, 446 

 Otariidae (mammals: eared seals; see Pinni- 

 otter: Lutra, q.v. [pedia) 



Ouradnik, 551 

 Ovio, 322, 350 

 owl parrot: Strigops, q.v. 

 owls 



accommodation in, 281, 655 

 ancestry of, 190, 208 

 area temporalis and fovea of, 187-188, 

 308-309 

 elongated visual cells of, 692 (entry for 



p. 195) 

 as pupillomotor area, 185 

 'blindness' in daytime of, 168 

 cornea : retina areal ratio of, 289 

 critical fusion frequency of, 354 

 eyes in 



closure of, as habit, 546-547 

 frontality of, 309, 320,331,413 



