淡水贝类贝壳多层构造形成研究

对几种淡水贝（包括蚌、螺）进行形态及组织学观察，并通过实验方法重现贝壳三种物质，即：角质、棱柱质、珍珠质的生成过程，结果表明：外套膜外表皮细胞是由相同类型细胞组成，这些相同细胞在不同的作用条件下形成贝壳多层构造。

ON THE FORMATION OF THE MULTILAYER STRUCTURE IN SHELLS OF SOME FRESHWATER MOLLUSKS

The formations of multilayer structure in shell of some freshwater mollusks (included bivalves and snails) were observed. The results obtained indicate that the mantle can be divided into three parts in bivalve molluscs with shell consisting of three Layers or two parts in snails with shell consisting of two Layers: (1)The marginal mantle (mantle edge). The secretory activities of the epthelial cells of the outer surface in this part of mantle is under the direct influence of the water surroundings. The secretion of this part of mantle forms the periostracum (cutin)Layer of the shell; (2)the Movement (or displacement)part of mantle, This part is located in the marginal and submarginal area of mantle in bivalve mollusc with a shell consisting of three Layers(or with pallial muscle impression on the shell),and is almost the whole mantle in snails. This part forms the prismatic Layer of shell; (3)The immobile mantle. This part of mantle is immobilized by fixing the mantle on shell at the position of impression of pallial muscle;such as the middle portion of mantle in bivalve mollusc with a shell consisting of three layers. The pearl layer of the shell is produced by this part. Experiments that form the three types of material of shell (periostracum. prismatic. pearl)have been done, of the artificial influences on the process of cultivation of attached pearl (or figured pearl) in species of Anodonta supported the obove view. Therefore, the epithelial cells of the outer surface in mantle possess the same secreting function and could form the multilayer structures in shells in mollusc.