Histochemical and Ultrastructural Analyses of the Epithelial Cells of the Body Surface Skin from the Terrestrial Slug, Incilaria fruhstorferi

Abstract Dorsal and ventral epithelium of the terrestrial slug, Incilaria fruhstorferi, is simple and consists of five cell types: microvillous, ciliated, round mucous, tubular mucous and channel. Microvillous cells were similar to human intestinal epithelial cells morphologically and functionally. At the base of microvilli, pinocytic vesicles which ultimately fused to form larger vacuoles, or multivesicular bodies were present. At the edge of tail or mouth, ciliated epithelial cells possessed the typical axonemes (9 plus 2 arrangement of microtubles). Mucous secretory cells were either tubular or round and their granules were membrane-bound and secreted by exocytosis. Granules of round mucous cells were proteinaceous but those of tubular cells were acidic mucopolysaccharides. Channel cells were elongate U-shaped and the central lumen was filled with a large amount of fluid (hemolymph). The function of channel cells is thought to remove hemolymph accumulated during hyperhydration. Our experiments of some ...