CHANGES IN STRUCTURE AND FUNCTION OF VENTRAL EPIDERMIS IN HYLA-ARBOREA-SAVIGNYI AUD (ANURA, HYLIDAE) THROUGHOUT METAMORPHOSIS

The changes in epidermal ultrastructure during the metamorphic cycle o f Hyla arborea are described. The number of cell layers increased from two to four in the late tadpole stages. The cell layers flatten and t he process of stratification reaches its peak after the completion of metamorphosis. The mitochondria-rich cell appears early in the tadpole stages. Numerous flask cells are noticeable in the post-metamorphic s tages. K+-p-NPPase activity was localized cytochemically in the epider mis of H. arborea during its metamorphic cycle. In the epidermis of th e legless tadpole, evidence for K+-p-NPPase activity was confined intr acellularly. During the later tadpole stages, preceding metamorphic cl imax, the main ATPase activity shifted to the base-lateral cell membra nes bordering with the intercellular spaces under the surface and late r the stratum corneum. This continued after metamorphic climax in the juvenile toadlets, diminishing later in the adult stage.