[Annals N. Y. Acad, Sci., Vol, XVIII, No. 5, Part II, pp. 149-180. Pll. VI-VIII. 

 Author's separates published 23 April, 1908.] 



THE PRODUCTION OF SOUND IN THE DRUMFISHES, 

 THE SEA-ROBIN AND THE TOADFISH.^ 



By R. W. Tower. 



CONTENTS. 



Introduction. 



Anatomy of the swim-bladder. 

 The drumfishes: 



Bearded drum (Pogonias cromis), 

 Squeteague {Cynoscion regalis), 

 Croaker (Micropogon undulatus), 

 Other drumfishes examined. 

 The sea-robin and the toadfish: 



Sea-robin (Prionotus carolinus), 

 Toadfish (Opsanus tail). 

 Sound production in the dnmifishes: 



Recorded observations and theories. 

 Experiments to determine cause of sound, 

 Experiments to determine character of muscular contraction, 

 Experiments to determine pressure of gas in swim-bladder. 

 Sound production in the sea-robin and the toadfish: 



Experiments to determine cause of sound and character of mechanism. 

 Conclusions. 

 Literature cited. 



Introduction. 



The production of sounds by certain fishes has long been an interesting 

 subject of investigation. Some species, as Scomber brachyiirus, by rubbing 

 together the pharyngeal teeth make a noise resembling a harsh grunt; some, 

 as the puffer, or swellfish, make a similar sound by rubbing together the 

 incisor teeth of the upper and lower jaw. In other cases stridulation has 

 been recorded, and sounds are also said to be produced by the forcing of 

 air through the pneumatic duct in those fishes in which the air-bladder 



1 Read by title at the meeting of the Academy on 13 April, 1908. 



149 



