part of develops from start stage end stage epidermis epidermal superficial stratum TAO:0001179 zebrafish_anatomy ZFA:0001179 The outer layer of the epidermis. The living cells form single cell layer, the outer surface of which is ornamented with microridges. These outer epidermal cells are not renewed periodically, but are individually replaced when dead. periderm portion of tissue pharyngula:prim-5 adult