CYTOCHEMICAL AND BIOCHEMICAL OBSERVATIONS ON DIGESTIVE TRACTS OF DIGENETIC TREMATODES .5. ULTRASTRUCTURE OF SCHISTOSOMATIUM-DOUTHITTI GUT

The gut of Schistosomatium douthitti can be conveniently divided into two distinct regions, the esophagus and the cecum. The former region is a syncitium with the underlying cell bodies communicating with the cytoplasmic layer via extensions. Multivesicular inclusion bodies are apparently produced by these cells and are secreted into the lumen via luminal processes. Two other types of inclusion bodies are evident in the anterior region of the esophagus. These are identical with inclusion bodies found in the tegument, supporting the premise that the anterior region of the esophagus is probably a modified tegument. The cecal region consists of a gastrodermis that also possesses processes on its luminal surface. No evidence of endocytotic activities is observed in the gut. The major difference existing between the gut of male and female worms is consistent with the greater digestive activities of the latter sex. Comparisons between the ultrastructure of the gut of S. douthitti and other bloodfeeding trematodes are discussed. © 1969.