The study investigates cell junctions in the amphibian epidermis, a stratified squamous epithelium, and compares them to those found in mammalian cavitary organs. In adult frogs and toads, as well as in larvae approaching metamorphosis, belts of membrane fusion (zonulae occludentes) are regularly found between adjoining cells of the outermost layer of the stratum corneum, binding the cells into a continuous sheet. Additional sets of occluding zonules are present in the second cornified layer and the outermost layer of the stratum granulosum. Specialized elements such as "modified" and "composite" desmosomes are observed along the lateral and basal aspects of the cornified cells, respectively. Ordinary desmosomes and maculae occludentes are found in all other strata. The intercellular spaces in the stratum germinativum maintain a typical 200 Å gap, while the intercellular spaces in the epidermis form a largely continuous network closed to the external medium and open to the dermal interstitium. The findings suggest that zonulae occludentes impede the diffusion of water, ions, and small water-soluble molecules, while zonulae and maculae occludentes facilitate cell-to-cell communication within the epidermis. The study also discusses the structural aspects of the junctional elements, including the presence of two distinct types of secretory granules in amphibian epidermal cells.The study investigates cell junctions in the amphibian epidermis, a stratified squamous epithelium, and compares them to those found in mammalian cavitary organs. In adult frogs and toads, as well as in larvae approaching metamorphosis, belts of membrane fusion (zonulae occludentes) are regularly found between adjoining cells of the outermost layer of the stratum corneum, binding the cells into a continuous sheet. Additional sets of occluding zonules are present in the second cornified layer and the outermost layer of the stratum granulosum. Specialized elements such as "modified" and "composite" desmosomes are observed along the lateral and basal aspects of the cornified cells, respectively. Ordinary desmosomes and maculae occludentes are found in all other strata. The intercellular spaces in the stratum germinativum maintain a typical 200 Å gap, while the intercellular spaces in the epidermis form a largely continuous network closed to the external medium and open to the dermal interstitium. The findings suggest that zonulae occludentes impede the diffusion of water, ions, and small water-soluble molecules, while zonulae and maculae occludentes facilitate cell-to-cell communication within the epidermis. The study also discusses the structural aspects of the junctional elements, including the presence of two distinct types of secretory granules in amphibian epidermal cells.