(Gastropoda: Pulmonata). Arquipélago, Life and Marine Sciences. Supplement

Little information exists on the histology of Zonitidae digestive system. This study deals with a detailed characterisation of the differeni types of cells comprising epithelium lining the digestive gland of 0,rychilus atlar~ricus. Frorn liglit and scanning electron microscope (SEM) studies, three types of differentiated cells can be identified in the digestive gland: digestive cells, cxcretory cells and calcium cells. Digestive cells are the most numerous, and are present in two forms, one believed to be absorbing food material and the other secreting material. Excretory cells are distinguished by having a large central vacuole, containing excretory granules. Calcium cells contain spherules of calcium salts. which have a characteristic birefringence