Indexed on: 01 Sep '75Published on: 01 Sep '75Published in: Zoomorphology
Different embryonic and postembryonic stages of capsular fluid containing cells of the midgut region in Lymnaea stagnalis L. are described. These cells arise from the archenteron and take up a great quantity of capsular fluid in a large vacuole. At hatching the diameter of the cells mesures 160-200 μ. In opposition to the opinion of Cumin (1972) these store-cells do not transform into cells of the adult midgut; they degenerate in the early postembryonic period. The degeneration starts in a diminuishing of the cell size. Later on autophagic vacuoles can be observed in the cytoplasm, the membrane of the large vacuole breaks up and the nucleus begins to degenerate. Membran bounded granules, which can be observed mainly in early postembryonic stages, are thought to be primary lysosomes. In a last phase the cells seem to be taken up by indifferent cells of the adult midgut.