Of course we should not swallow hook, line and sinker the stories of dragon's offspring and squealing fish, and today we can be absolutely sure that in both cases only one creature was responsible for all the excitement - Proteus anguinus. But the human fish appears not to complete the metamorphosis. It reaches sexual maturity as a larva. So far, science has still not entirely explained neoteny, as this phenomenon is called. But one thing is certain, namely, that this peculiarity is somehow connected with the production of the hormone thyroxine, in spite of the fact that proteus does not react to the substance in the way other amphibians do.
Scientists have many attempts to force the unfortunate proteus to metamorphose, but in vain.
The animal stays all its live and breathes through gills, althoug it also has rudimentary lungs. He did not include proteus to his natural order as an independent animal species and, of course, made a big mistake. I feel that the mocheril is a separate animal genus. And he was quite right. Scopoli could not keep his enthusiasm about the discovery of a new animal species to himself.