Rete Mirabile in the Gas Bladder of Coregonus lavaretus

Abstract

IN fishes with gas secretion both a gas gland epithelium and a counter-current capillary system are usually found in the gas bladder. This is true of physoclists and a large number of physostomes. Data on the composition of the gas bladder gases in coregonids indicate the presence at least in some species of an oxygen-transporting mechanism¹. Experimentally gas secretion has been demonstrated in other salmonids as well². Because no rete mirabile has been found in salmonids, it has been supposed that in these fishes a pure cellular gas secretion without participation of any counter-currentmultiplier system takes place³. The discovery of a rete mirabile in Argentina ⁴, which is systematically related to the salmonids, might lead one to expect to find this structure also in the gas bladder of the latter. The fact that it has not been observed by previous investigators could be due to an unusual anatomy of the rete system.