Starling, effects of light, 27 

 gonads and behaviour, 82 

 structure of ovary, 57 

 Sterility, in concentration 

 camps, 13 

 in zoological gardens, 14, 41 

 Subterranean animals, ques- 

 tion of, 30 



Temperature, effects of, 24, 



39 

 Testis, effects of removal, 83 

 hormones of, 53 

 structure of, 51 

 Testosterone, 54, 64 

 Testosterone propionate, 



effects on behaviour, 88 



INDEX 123 



effects on social domin- 

 ance, 89 

 Tropics, breeding in, 34 

 Trout, autumn breeding in, 



Tuatara lizard, long develop- 

 ment of, 8 



Ultra-violet light, effects of, 

 35, 36, 74 



Wakefulness, effects on junco, 

 74 



Zoological gardens, sterility 

 in, 14, 41 



