ORIGIN, COURSE AND DISTRIBUTION OF THE VENAE CORDIS IN THE DONKEY. (EQUAS ASINUS)

The venae cordis in the doneky can be classified in the current study as major (V. cordis magna and V. cordis media) and minor (Vv. cordis dextrae and - Vv. cordis minimae) vessels. The major ones open via a valveless orifice in the Atrium dextrum. The V. cordis magna possesses a well developed valve, and the V. cordis media, has an ill- developed one near their origins. The former vessels, drains mainly the Ventriculus sinister and the Atrium sinistrum, as well as the Conus arteriosus. The V. cordis media, on the other hand, drains chiefly the two ventricles. An obvious intervenous anastomoses can be demonstrated between the terminal branches of the two major vessels. Collectively, the vessels co-operate to drain the Septum interventriculare via 8 to 10 small Rr. septales. The Vv. cordis dextrae are represented by two considerable branches which drain the Atrium dextrum as well as the Ventriculus dexter. Furthermore, an anastomoses between these branches and those of the V. cordis magna, can be traced. The Vv. cordis minimae were represented by several minute vessels being interposed within the myocardium and emptied into the Atrium dextrum as well as the Ventriculus dexter.