THE TALKING-FISH. 139 



continued the subject of the "talking-fish," as 

 Tom called it. 



" This," he said, " is one of seventy or more 

 known sound-producers among the fishes, and the 

 variety of noises they make would give you ample 

 material for a fish dictionary. They are caused 

 probably by either the lips, the bones of the 

 pharynx, or the air-bladder, and are in many cases 

 involuntary. In the latter class are the fishes 

 known as Zeus and Trigla, in which the swim- 

 ming-bladders have a diaphragm which is opened 

 and closed by curious muscles, the operation be- 

 ing accompanied by a murmuring singing sound. 

 The cat-fishes and eels speak, we will say, by 

 forcing air from this bladder into the oesophagus ; 

 the former produce a curious crooning noise, 

 while the eels make a somewhat musical sound. 

 It is generally a soft note rapidly uttered, with 

 imperceptible variations, and having a decided 

 metallic ring at times like the distant stroke of 

 a tuning-fork. The mud sun-fish, so common in 

 the Connecticut and Hudson Rivers, makes a 

 sound very similar to the grunt, only in a deeper 

 bass. The gizzard shad utters a loud whirring 



