part_of part of part of adjacent to developmentally replaces Homo sapiens skin epidermis epidermal Zebrafish epidermis consists only of living cells unlike terrestrial vertebrates in which dead, keratinized cells are present. In terrestrial vertebrates the epidermis often forms an outer keratinized or cornified layer, the stratum corneum. Interaction between the epideris and dermis gives rise to feathers (birds), hair and mammary glands (mammals), teeth and scales (placoid: chondrichthyans; cosmoids, ganoid, cycloid in bony fishes). dermis skin of body periderm outer epithelium external integument structure