CONTENTS 



INTRODUCTION ""i.^i 



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 n 



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 HI 



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 



