80UND8 n;t'I>i CJ 1> BY FISH. 



157 



will be obtained by cutting the fi»h througli 



curd is Been to \\>- above the vertebral column, the : i 

 being formed by tbe interarcbing spinous pi B( low I 



bral column is the large cavitj containing the heart, stomach, 

 while the rest of the section is occupied b; 



The noi.- luced by certain fishes are due to the 



action of the pneumatic duel and swimming-bladder (1 _. 

 801, v . S"), though different kinds of nois 

 dentally or involuntarily by the lips or the bo ' the 



mouth, as in the tench, carp, and a large number of other 

 fishes. Over fifty - e known to produce 



sounds of somesort. The swimming-bladders of Trigla&nd 



Fig 901.— Swimming bladder (5. anterior, S', posterior division 1 >>f thi 

 phagus; I. air-passage of the air-bladde 

 Kr. 'in Semper. 



Zeus have a diaphragm and muscles for opening and • 

 ing it, by which a murmuring sound is made. The lou 

 sounds are made by the drum-fish. In some minn 

 pouts, and eels the sound is made by forcing the air from 

 the BWimming-bladder into the oesophagus. In the 



3e, the Bounds an - 1 by the vibrati< rtain 



small voluntary musi 



The mud sun-fish (Acanfharrhvs utters id 



grunting sound; the g i shad (/' iianum, 



Fig. 202) makes "an audible whirring sound;" the chub- 

 sucker or mullet (Erxmyzon m) "i ngle 

 prolonged note accompan ed.by a discharge of air-bubl 

 the oat-fish produces "a gentle humming sound;" eels 



