a type of secretion in which the entire contents of a mucus-secreting cell is converted to a secretion. Cells are shed in this way by the epithelial layer, which is generally stratified epithelium. The lost cells are replaced by the reproduction of cells in underlying layers. Holocrine secretions are characteristic of sebaceous glands and the reticular zone of the adrenal glands of vertebrates and man, the poisonous cutaneous glands of amphibians, and the mucous sacs of some Cyclostomata.