An ultrastructural study of the cere of the domestic pigeon (Columba livia).

The relative scarcity of primary and secondary skin infections in birds depends, at least in part, on the functional morphological barrier presented by the avian integument. Both transmission and scanning electron microscopical techniques were used to study the ultrastructural morphology of the epidermal barrier in the cere of the domestic racing pigeon. The epidermis is composed of sebokeratocytes which are responsible for producing not only the keratin proteins of the keratinized stratum corneum, but also the lipid emulsion forming the surface lipid layer and filling the intercellular spaces. The possible importance and role of these components in the defensive barrier presented by the skin is discussed.