Evidence is presented that mammalian membrane-coating granules, avian multigranular bodies, and reptilian mesos granules are homologous structures. All three types which will here be called lamellar granules have the following items in common: (1) A lamellar pattern produced by disks stacked coin-like above each other. (2) Major dense lines separating adjacent disks, each of which contains a minor dense line. (3) Spacing between and thickness of major densè lines. (4) Positive reaction with various lipid stains, PAS, and the Thiéry silver method. (5) Disappearance of the lamellar pattern after treatment with lipid solvents or phospholipase C. (6) Extrusion of contents into the intercellular space and its rearrangement into broad sheets running parallel to the surface of the horny cells. Based on these observations and biochemical results (Elias et al., 1979, J. Invest. Dermatol. 73, 339–348) the lamellar contents (disks) are interpreted as “flattened” liposomes.