The digestive gland of Viviparus ater (Mollusca, Gastropoda, Prosobranchia): An ultrastructural and histochemical study

The digestive gland of Viviparus ater was studied using histochemical and ultrastructural methods. Only one cell type was observed in the tubule epithelium of the gland. The cells are involved in an endocytotic process mediated by clathrin-coated vesicles and in the intracellular digestion of food materials (thus they can be regarded as digestive cells). The different stages of digestion and exocytotic extrusion of residual bodies into the tubule lumen were shown by electron microscopy. Very few, small myocytes are scattered among the digestive cells. Calcium concretions, glycogen-containing cells and endocrine cells are scattered in the area of connective tissue present among the digestive tubules.