[Light and electron microscopy analysis of the differentiation of oropharyngeal epithelium in Salamandra salamandra (L.) during metamorphosis (Urodela:Salamandridae)].

During metamorphosis the oropharyngeal-epithelium of Salamandra salamandra consists of cells partly with features typical for larvae partly with these characteristic for metamorphosed animals. In the stratum intermedium cells which in larvae develop to secreting non-ciliated pavement cells become precursors of ciliated cells. During this process mucus granulus were discharged and cells develop cilia. Cells of deepe layers stop the production of mucus granules; those granules, which are already present, disintegrate. Furthermore, new types of goblet cells (type 2 and 3 according to Clemen, 1984) arise. Goblet cells of older larvae (typ 1) are to be found nearly unchanged in metamorphosed animals. Older goblet cells degenerate. In the stratum superficiale during transformation of pavement cells to ciliated cells discharge of mucus and ciliogenesis run parallely. Some of the pavement cells, however, degenerate. The stratum basale remains unaltered.