I believe he is rising now from some management of the air-bladder.
The air-bladder large and strong, and in some cases notched on the margin.
But the primal purpose of the air-bladder was not to serve as a float.
In the sharks, rays, and chimæras there is no trace of an air-bladder.
The elasticity of the air enables fishes to rise and sink in water, through the action of the air-bladder.
A point of Natural History being suggested, he gave an excellent account of the air-bladder of fishes.
Below, the processes spread apart, surrounding the kidneys and partly enclosing the air-bladder.
They expel the air from their air-bladder; in consequence of which, their size is diminished, and they sink instantly.
These fishes generally have an air-bladder, and the gills lie close together in a cavity covered by an operculum.
Like others of his kind Sammy had a very strong spine in which was an air-bladder.