274 HITCHCOCK'S ANATOMY 



Fig. 269. Fig. 270. 



ILung of Turtle laid open. Gills of Eel. A. Enlarged Portion. 



In aquatic serpents the amount of air contained in the body 

 tends to make it buoyant, and at the same time supplies the 

 wants of the animal .during a long immersion. In frogs and 

 many of the class reptilia the air is forced into the lungs by 

 a process similar to that of swallowing. Taken as a whole, 

 this order is remarkable for the feebleness of its respiratory- 

 actions, and the length of time which the function can be sus- 

 pended without injury. The temperature in which the ani- 

 mal lives, however, greatly modifies the amount of air exhaled 

 and inhaled. 



486. Gills of Fishes. — The Bespiratory apparatus of 

 Fishes consists of Gills for procuring the air contained in 

 water. The Gills are fringes of minute bronchial tubes sus- 

 pended from cartilaginous and bony arches, that are situated 



How do frogs inspire ? What efiect has the temperature upon the respiration in this 

 class of animals ? 486, What are the organs of respiration in fishes? Describe the gills. 



