STUDIES ON HISTOLOGY AND SCANNING ELECTRON MICROSCOPE OF DIGESTIVE TRACT OF CHINESE MITTEN-HANDED CRAB(ERIOCHEIR SINENSIS)

Taking out digestive tract of Chinese mitten handed crab(E. Sinensis), esophageal anterior segment and posterior segment; cardiac fundus, cardiac side and back; midgut anterior segment and posterior segment; intestinal bulb anterior segment and posterior segment, and posterior blind sac; hindgut anterior segment, middle segment and posterior segment were divided and made specimens. By using the technique of scanning electron microscope, the ultrastructure characteristics of the surface of epithelium mucosae of every segment digestive tract of Chinese mitten handed crab(E. Sinensis), and at the same time histological structure were observed. The results showed that there were the more thick lamena secreta and the more developed lamena cilia in the surface of epithelium mucosa of whole digestive tract except in the midgut and posterior boind sac. The distribution density and form of cilium were difference in different places of digestive tract. The distribution density of cilia were the most in the esophagus and hindgut, and took second place in the stomach and intestinal bulb. The multipolar folds and ridges differed in size and in shape in the surface of epithelium mucosa of each segment of digestive tract. Only in midgut there was structure of the typical microvilli. No goblet cells were found in the surface of epithelium mucosa of each segment of digestive tract. The basement membrane was developed under epithelium. The submucous layer was clear, and the digestive gland distributed among it. The muscular coat of whole digestive tract wall Consisted of striated muscle but its arrangement was loose. The most membrana externa was the membrana serosa.