CONTENTS xvii 



Interrupted Dark Period: Tests for Refractoriness in Bob- 

 white Quail Hens, by Charles M. Kirkpatrick 751 



The Influence of Different Day Lengths on the Testes of a 

 Transequatorial Migrant, the Bobolink {Dolichonyx oryz- 

 ivorus) by William L. Engels 759 



Photoperiodism in the Female Domestic Fowl, by R. M. 



Fraps 161 



Egg Production of Chickens in Darkness, by W. O. Wilson 



and A. E. Woodard I'&l 



Section XI Control of Periodic Functions 

 in Mammals by Light 



Experimental Modification of Mammalian Endogenous Ac- 

 tivity Rhythms, by Kenneth S. Rawson 791 



Experiments on Light and Temperature in a Wild Mammal 

 with an Annual Breeding Season, by Lemen J. Wells 801 



Physiologic 24-Hour Periodicity in Human Beings and Mice, 

 the Lighting Regimen, and Daily Routine, by Franz Hal- 

 berg, Erna Halberg, Cyrus P. Barnum, and John J. Bittner 803 



Genera and Species Index 879 



Subject Index 885 



