[Ultrastructural and cytochemical characters of the primordial germ cells of the Anuran amphibians (author's transl)].

Transmission electron microscopy was used to study Anura Amphibia primordial germ cells (PGCs). Our results demonstrate the evidence of an extracellular matrix and many various cellular junctions between the somatic cells and the PGCs. Furthermore, from cytochemical investigation, it appears that there is abundant cytoplasmic glycogen and also membrane adenyl-cyclase activity. At last, the results are analysed, discussed and related to the hypothesis of the guidance of the migration of the Anura PGCs by cAMP diffusing from the chordo-mesoderm.