CONTENTS 



INTRODUCTION ... . . . i-n 



CHAPTER I 



THE ORIGIN OF THE VOICE 



Darwin's opinion that the voice resulted from involuntary move- 

 ments of muscles Combat the chief occasion for such move- 

 ments Prevalence of a puff or hiss as a menace Accidental 

 cries of newts . . . , ' . 12-21 



CHAPTER II 



ALARM-NOTES 



Combat-cry serviceable as an alarm Repetition of single alarm- 

 cries, in terror Theory of evolution of certain rattling cries 

 by such repetitions Discrimination of enemies evidenced by 

 cries and deportment Inherited knowledge of alarm-cries 22-32 



CHAPTER III 



THE INFLUENCE OF COMBAT 



Rivalry and emulation Among polygamous species, selection 

 dependent on combat The snapping of bill as a menace 

 Chaffinch's war-note Singing during combat . . 33-40 



