These fishes generally have an air-bladder, and the gills lie close together in a cavity covered by an operculum.
I believe he is rising now from some management of the air-bladder.
In every modern Dipnoan, Crossopterygian, and Ganoid the air-bladder has an effective pneumatic duct.
The air-bladder large and strong, and in some cases notched on the margin.
Like others of his kind Sammy had a very strong spine in which was an air-bladder.
In the sharks, rays, and chimæras there is no trace of an air-bladder.
Unlike the lung of the Dipneusti, this air-bladder is not cellular, and it receives only arterial blood.
They expel the air from their air-bladder; in consequence of which, their size is diminished, and they sink instantly.
The elasticity of the air enables fishes to rise and sink in water, through the action of the air-bladder.
The air-bladder resembles the lungs of terrestrial vertebrates.
|air bladder |