TEM and SEM investigations of lymph hearts in birds

The fine structure of lymph hearts in birds is described. These organs could be made visible by application of marker medium and indirect and direct injection of contrast medium. As two special morphologic features we note strange modified skeletal muscle cells in the wall of the lymph hearts and efferent collectors to the epidural spinal lymphovenous sinus. The lymph hearts possess valves that regulate the passage of lymph from the lymphatic copulatory organ and the thoracic duct into the venous blood system.