[Ultrastructural study of the first stages of ovarian post-embryonic differentiation of the paludin Viviparus viviparus L. (Mollusca, Gastropoda, Prosobranch of separate sexes)].

The young Paludin ovary, characterized by its tubular morphology, contains at birth two types of cells: the germinal ones, and others which give later follicular cells. There is no significant cytological difference between the primordial germinal cells of female and male gonad. Among the several cytologic criteria that allow one to distinguish the germinal line from the non germinal one, the most constant is the presence of septate junction between the non germinal cells.