146 VITAL FUNCTIONS. 



cess of respiration is performed by taking the water 

 into the mouth, and forcing it through the gills, which 

 separating their filaments exposes every part to its 

 action. 



In the cartilaginous fishes, or those which have no bony 

 frame, as the lamprey, there is no operculum provided 

 for the escape of the water during respiration, but 

 instead of this, there are several apertures along the 

 sides of the neck, or throat through which, the fluid is 

 thrown. 



Respiration in the Lamprey. In the Lamprey often 

 called the Lamper-eel, which is one of the cartilaginous 

 tribe, the organs of respiration are so constructed as to 

 be independent of the mouth in receiving the water. 

 In this fish there are seven external openings, Fig. 90, on 



Fig. 90. 



each side leading into the same number of separate 

 oval bag-like appendages, situated horizontally, the inner 

 membrane of which, has the structure of gills. Into 

 these openings the water is drawn by the action of cer- 

 tain mucles, and having performed its office, is again 

 ejected by the same orifices. 



Were it not for this curious and singular provision, 

 the Lamprey would be unable to enjoy its usual habit of 

 adhering by the suction of the mouth to a smooth stone 

 or other solid, or grasping and sucking its food by which 

 it lives. 



ATMOSPHERIC RESPIRATION. 



Having thus described the respiratory organs in seve- 

 ral orders of inferior animals, we now come to those, 



What difference is there in the respiration of the cartilaginous and 

 bony fishes ? 



