MORPHOLOGICAL, HISTOLOGICAL AND HISTOCHEMICAL STUDIES ON THE DIGESTIVE SYSTEM OF SCAPHARA SUBCRENATA(LISCHKE)

The structure and function of the digestive system of Scapharca subcrenata was studied by anatomical, histological and histochemical methods. The digestive system of Scapharca subcrenata consists of the digestive tract and digestive diverticula.The digestive tract is composed of the labial palps, mouth, esophagus, stomach, style sac, intestine, rectum and anus. The tract except the labial palps and style sac consists of mucous membrane, submucosa lamina, lamina muscularis and adventitia. The mucous membrane is made up of epithelial lining and lamina muscularies mucosae. The type of epithelial lining is simple ciliated columnar epithelium, but the mouth and the esophagus are pseudostratified ciliated columnar epithelium. A part of the stomach and the intestine has no muscular layer. The adventitia is composed of fibrosa, except serosa covering the wall of ventical mouth. The digestive diverticula is the type of compound tubuloacinar gland which communicates with the stomach by a system of ducts. The glandular epithelium is formed by four types of cells :embryo cell (E-cell),fibrillar cell(F-cell),resorptive cell(R-cell) and secretory cell(B-cell). There are phagocytes in the lumen of mouth, esophagus, stomach and intestine. Intense alkaline phosphatase activity was detected in the epithelium of intestine glandular epithelium. The epithelium of stomach and intestine and glandular epithelium show strong activity of acid phosphatase. Ca and Fe exist in the submucosa lamina of stomach and intestine the glandular epithelium, and the connective tissue of the digestive diverticula.