Because they have no neck. In some, indeed, the stomach seems to open directly into the mouth. The gullet is, however, capable of great extension, and when the stomach is unable to hold the whole of the prey, which has been seized, a part remains in the gullet until the inferior portion gives way. - Fleming.
Because this organ in the cod or ling, when salted, forms nourishing and palatable food. But it is chiefly in the manufacture of isinglass, that the sounds of fishes are extensively employed. Sturgeon sounds are chiefly used for this purpose.
When in a sound state, the external skin of the air-bag (regarded as possessing strong muscular power) is supposed capable of contraction, so as to condense the air, and enable the animal to sink ; or of extension, so as to allow the air to expand, and aid the animal in rising in the water.
Because it consists almost entirely of gelatine.
Because this bladder does not exist in many fishes.
Because it is largest in such fishes as swim with considerable velocity.
Because they have no air-bladder to enable them to swim. In the shark the absence of the air-bladder is compensated by the size and strength of the tail.
Because it has neither air-bladder nor fins to enable it to swim.
Because the skeleton is more complicated than that of man, and is difficult to prepare and preserve. - Fleming.
The bones of fishes, when reduced to powder, are mixed up with farinaceous substances, and used instead of bread, by some of the northern nations.
Because of a violent effort of the caudal fin ; or, according to some, by bending the body strongly, and afterwards unbending it with an elastic spring.
Because they have the air-bag of uncommonly large dimensions, wherefore the body has great buoyancy. The pectoral fins are likewise large, and having, by a leap raised themselves above the surface of the water, they continue in the air and move forwards, seldom farther than a hundred yards, by the action of these fins.
Because the membrane of their fins soon becomes dry, when they again fall into the water. The flying fish generally leave the water to escape from other fish which prey upon them.
There is also a species of fish which is capable of climbing, and has been known to raise itself five feet above the surface of the water, and mount up the crevices of trees, by means of its various spines.