[Ontogenesis of the endocardial cushions in the vertebrate heart. An experimental- and comparative embryological study (author's transl)].

By means of comparative ontogenetical findings and organ cultured whole hearts of tadpoles (Xenopus laevis) there has been evidence that the localization of the endocardial cushions in the embryonic heart tube of landliving vertebrates is phylogenetically caused. On the contrary ontogenetically the shape of these cushions are dependent on the varying hemodynamic conditions in heart development. By this the anlage of endocardial cushions are the presupposition of the phylogeny and ontogeny in the septation of the heart in tetrapodes.