MORPHOLOGICAL CORRELATE OF REGIONAL PARTITIONING OF INTEGUMENTAL WATER-ABSORPTION IN TERRESTRIAL SLUGS

An ultrastructural study of the foot surface of the terrestrial mollus c, Limax maximus, has revealed a correlation of epithelial cell type w ith the functional partitioning of the surface. The lateral absorptive bands of the foot are comprised exclusively of microvillar epithelial cells, while those of the medial locomotor band are all ciliated. Thu s, there is a clear partitioning of epithelial cell types between area s of the foot surface with distinct functional roles. Consistent with the proposed role for paracellular absorption, varying states of hydra tion are shown to affect the extent of the intercellular spaces, but n ot the intracellular architecture.