SURFACE ARCHITECTURE OF THE OPERCULAR EPIDERMIS AND EPITHELIUM LININGTHE INNER SURFACE OF THE OPERCULUM OF A WALKING CATFISH, CLARIAS-BATRACHUS

In Clarias batrachus, the opercular epidermis (OE) and epithelium lini ng the inner surface of the operculum (EISO) showed significant differ ences in their surface architecture, such being correlated with differ ent conditions at the two locations. The surfaces of the epithelial ce lls had characteristically intricate patterns of microridges, which we re mostly short-ridged with narrow spaces between them (OE) or high-ri dged and widely spaced (EISO). These patterns were believed to be asso ciated with the relative extent of surface secretory vesicles, present for the secretion and renewal of the extra-cellular cuticular coat at these locations. Extensively distributed on the OE, wide mucous cell openings enable increased mucus secretion, considered to be an adaptat ion resulting from the greater need for lubrication, protection and in hibition of invasion and proliferation of pathogenic microorganisms, t han at the EISO, where mucous cell apertures were few and narrow. Tast e buds were generally situated at papillate, epidermal elevations that projected from the OE surface. This possibly enhances gustatory funct ion, being an adaptation compensating for reduced vision. The absence of taste buds in the EISO suggested that a gustatory function does not occur in that region.