Abstract: | Epidermal surface cells were studied ultrastructurally and histochemically at various larval stages in Salamandra salamandra. The most outstanding cellular structures undergoing changes were found to be secretory vesicles, mitochondria and tonofilaments. The highest density of secretory vesicles was noticed immediately after birth, declining in number at later stages and almost disappearing at metamorphosis. The mitochondria, whose appearance at early stages indicates a high metabolic activity, hypertrophy and degenerate close to metamorphosis. Simultaneously, there is an increase in the cellular tonofilaments' density reaching its climax with keratinization. |