440 



ZOOLOGY, 



of the body of AmpJiipnous cucliia, Gymnarchus and Sacco- 

 branchus zincjio. 



The noises produced by certain fishes are due primarily to 

 the action of the pneumatic duct and swimming-bladder, 

 while different kinds of noises are made accidentally or in- 

 voluntarily by the lips or the pharyngeal or intermaxillary 

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

 fishes. Over fifty species of fish are known by Dufosse to 

 produce sounds of some sort, and Abbot has increased the 

 number in this country. The swimming-bladders of Triyla 

 and Zeus have a diaphragm and muscles for opening and 

 closing it, by which a murmuring sound is made. The 



Fig. 399. Gizzard Shad. 



loudest sounds are made by Pogonias cliromis, the drum- 

 fish. In some Cyprinince, Siluroids and eels the sound is 

 made by forcing the air from the swimming-bladder into the 

 oesophagus. In the sea-horse (Hippocampus), the sounds 

 are made by the vibrations of certain small voluntary 

 muscles. 



Dr. C. C. Abbot has in this country discovered that the mud 

 sun-fish (A rdtifltiirehus ptniwh'*) utters a deep grunting sound; 

 the gizzard shad (Dorosoma cepedianum, Fig. 399) makes "an 

 audible whirring sound ;" the chub-sucker or mullet (Erimij- 

 zon oblong um) "utters a single prolonged note accompanied 

 by a discharge of air-bubbles ;" the cat-fish (Ainlnrny 



