Résumé
The morphogenesis of the heart and the formation of the epicardium were studied with SEM, TEM and light microscopy. The results are as follows:1. There are two stages in the development of chicken heart: First is the formation of cardiac loop. In certain places, the sulcus appears outside, and the cresta appears inside during this stage. The formation of the cardiac loop indicates the establishment of the anlagen of the heart; Second is the differentiation of the anlagen, including the septation of the heart and the shift of each part of the heart. The shift of the atrium and the conus results from the shift of the right and left ventriculum. 2. The epicardium is not differcntiatcd from the myocardium, but formed from the mesenchymal cells which proliferate in front of the sinus venosus. These cells migrate and cover the entire surface of the myocardium.