Observations on the Physiology of the Swim Bladder in Cyprinoid Fishes

Abstract

1. Experimental proof is given that Cyprinoid fish can inflate their swim bladders either by swallowing air or, far more slowly, by secreting a gas rich in oxygen, although they have no gas glands in the ordinary sense of the term. 2. Attention is directed to the high gas pressure which such fish maintain in their bladder and its probable use is discussed. 3. The anatomy of the pneumatic bulb at the oesophageal end of the pneumatic duct in Cyprinoid fishes is described.