X - ray picture of the digestive tract of some species of Chondrichthyes (seu Selachi seu Elasmobranchii)

Abstract

       Owing to the fact that an ordinary postmortem examination cannot always give as precise results as X-ray screening of live and intact objects, we have decided to carry out X-ray investigations on some species of sea-fish. During the investigations described in this study we have examined by X-ray the digestive tract of the following species of Chondrychthyes: Scyllium canicula Cuv., Mustelus laevis Risso and Myliobatis aquila Dum. By using our modified X-ray method previously applied in our study of the digestive tract of fresh-water Actinopterygii (Švob, 1956), we have succeeded in making X-ray pictures of the digestive tract of the above mentioned species of sea fish. In that procedure, besides oral tubing, the application of the contrast (Barium sulfate) through the rear opening is of great importance. This method had to be adapted and modified for the study of the above mentioned species. Some new technical problems of investigation, due to the special kind of work on sea-objects, had to be solved, too.

       The X-ray investigations carried out in this work are technically more difficult than those concerning fresh-water fish. By means of these investi­gations morphological shape, size and topographic relations of the digestive tract, as well as outlims and relief of the mucuous membrane of that tract could be determined on live fish. Further more, we have also observed some physiological phenomena; however in investigating by X-ray the physiology of the digestive tract we have met with great technical difficulties.

       The results of our investigations provided additional morphologic infor­mation on the characters of the digestive tract of the studied species.