896 



SUBJECT INDEX 



Migration, in birds (Continued) 

 regulation in tropical and trans- 

 equatorial migrants, 681, 

 706-708 

 role of light and darkness in 

 initiating response, 686- 

 692, 700 

 Mitoses 



ear pinna, 8 1 6, 823, 862 

 interscapular epidermis, 823 

 liver parenchyma, 823, 849 

 Mitosis, 524 



diurnal periodicity of, 521 

 Monochromator 



for action spectra, 27 

 Moonlight, 615 



effect on breeding, 644 

 intensity of, 616 

 Morphogenesis, 126, 127 

 in Hyoscyamus, 1 13-1 19 



gibberellic acid, effects of, 114- 

 116, 118 

 in lettuce, 119-125 



gibberellic acid effects, 123- 



125 

 light intensity effects, 119, 



121-123 

 night temperature effects, 1 1 9 

 nitrogen effects, 1 19 

 varietal differences, 119, 122 

 Motor activity, 813-815, 823, 838, 



842, 844, 854, 864 

 Mouse (Peromyscus) , 797, 799 

 activity rhythms of, 792-796 



Naphthaleneacetic acid, 384, 388 

 Neurosecretory cells, 592, 593 

 Neurosecretory material, 729, 



730 

 Night interruption 



effect on Metatetnmychus, 621 



Night length 



determination of critical, 246, 249 



effect on induction of flowering, 

 245, 246, 248, 249, 251, 252 

 Nuclei, 520 



role in diurnal periodicity, 521 

 Nucleic acids 



and induction of flowering, 418 

 Nucleolus, 549 

 Nutrition 



in photoperiodic testicular re- 

 sponse, 737 

 Nyctinastic movements, 558 



Oogenesis 



infish, 654, 656, 660, 662 



effect of day length, 654, 656, 



660, 662 

 effect of day length-temperature 



combinations, 600-622, 656 

 effect of temperature, 656, 660, 

 662 

 egg diameters, 654, 655 

 growth phases, 654, 656 

 Optical density 



derivative of, 31, 32 

 Optical properties 



of cellular pigments, 15 

 Optic nerve 



pathway of stimulus to gonads, 

 645 

 Orthoptera 



photoperiodism in, 602 

 Oscillating system, 562 

 Ovarian cycles 



photoperiodic control of, 735, 

 736 

 Oviduct stimulation 



in quail, 755 

 Oxgen 



role in birch seed dormancy, 8 1 



I 



