762 



RADIATION BIOLOGY 



Retinula, 625 



Rhabdom, 625, 647 



Rhabdopleura, possible eyespot, 662 



Rhodin-g5, 109 



Rhodins, 96 



Rhodophyceae (red algae), 306, 308-310, 



356-i370 

 Rhodoporphyrin, 96 

 Rhodoporphyrin XV, 111 

 Rhodopseudomonas palustris, 376 



spheroides, 373, 374, 382, 384 

 Rhodospir ilium, 302, 327, 329 



rubrum, 373, 377, 378, 383-386 

 Rhodovibrio, 302 

 Riboflavin, 468, 469, 473 



as "conjugated" molecule, 17 



fluorescence of, 38 

 Ribulose-diphosphate, 320 

 Ricinus, 535 



Robber flies, distance estimation, 653 

 Rotifers, eyespots, 631 



photosensitivity, 631 

 Rumex, 529 



crispus, 539 



S 



Sabellaria larvae, photosensitivity, 635 

 Sagitta, photosensitivity, 632 

 Salkowsky test, 470 

 Salpa, ocelli, 662 

 Saponin, 528 



Sapphirina, single ommatidium, 656 

 Saturation at high light intensities, 260 

 Scattering of light, 346-348 



by algae, 264, 265 

 Scattering media, measurement of ab- 

 sorption spectra in, 346-348 

 Scenedesmus, 315, 318, 320, 322, 327 

 Scolecolepis, photoreceptors, 635 

 Scolopendra, ocellus, 634 

 Scorpionida, ocelli, 645 

 Screens, neutral, 189 

 ScuUgera, compound eyes, 646, 656 

 Scutum, ocellus, 634 

 Sebdenia sp., 358 

 Secondary ocelli of spiders, 644 

 Sedoheptulose phosphate, 320 

 Seed, topographic position, 532 

 Seed coats, removal, 533-534, 537 



respiration, 535 

 Seed germination, action spectrum, 491 

 Selection rules in photoexcitation, 4 

 Sensibilization, dcflnition, 521 



induced by gases, 531 

 Sensilla, 625 

 Sensitivity, to light (see Photosensitivity) 



spectral, 465 



"Sensitized" fluorescence, by carote- 

 noids, 304, 308 

 with chlorophyll, 43 

 among chroococcus pigments, 43 

 coupling required, 44 

 in photosynthesis, 59, 86 

 in proteins, 56 



rhodamine B by trypoflavin, 42 

 selection rules for, 43 

 Sepia eye, pigment change, 623 



visual field, 642 

 Sepiola, eye dimensions, 641 

 Sertularella, photosensitivity, 628 

 Shadow-response (see Off-response) 

 Shock-wave propagation, 29 

 Simocephalus, loss of eye pigment, 658 



ultraviolet sensitivity, 666 

 Simple eye defined, 624 

 Singlet states, 81, 86 

 Skotodormancy, definition, 520 

 induction, 529-530 

 {See also Dormancy) 

 Slit pupil in cephalopods, 642 

 Slugs, circus movements, 640 



dermal photosensitivity, 640 

 Soil as germination promoter, 527 

 Solar constant, 152 



Solar-energy conversion, efficiency, 294 

 Solar radiation in United States, 277 

 Solaster, accuracy of orientation, 659 



movement of ocelli, 659 

 Solen, photosensitivity, 638 

 Solid angle (steradian), 137 

 Solpugida, ocelli, 645 

 Solvent effects, 85, 91, 115 

 Soret bands of porphyrins, 96, 100 

 Spectra, absorption, 343-388, 473 



of active pigments, 344, 360-364 

 of carotenoids (see Carotenoids) 

 of chlorophylls, 301, 302, 305-307, 



354, 355, 371-384, 404 

 of ether extracts of barley leaves 



during greening, 395 

 of inactive pigments, 360-364 

 of living plant, 302, 303, 309, 343- 



388 

 measurement in scattering media, 



343, 346-348 

 of phycobilins, 309, 356-^364 

 of plant pigments, 343-388 

 of protochlorophyll, 404 

 of protopheophytin, 404 

 action, 343-345, 384-388, 469, 473, 526 

 chlorophyll formation, 410, 411 

 for fluorescence, 308, 309 

 of fluorescence excitation, 308, 309, 



366-370, 384-388 

 of photosynthesis, 309, 359-364, 

 384-388 



