MORPHOLOGICAL AND HISTOCHEMICAL OBSERVATIONS ON THE DIGESTIVE-SYSTEM OF COTYLOPHORON-COTYLOPHORUM

The amphistome Cotylophoron cotylophorum feeds entirely on semidigested rumenal contents (plant material living bacteria, and protozoa). Morphological and histochemical studies have been made of the digestive system. Two types of cells occur in the caecal epithelium, the first type were larger and cuboidal with granular cytoplasm containing a high amount of RNA and proteins. The second smaller type were fewer, and contained pyknotic nuclei; their cytoplasm was vacuolated. The cells of the first type bear microvilli at the luminal surface. The surface coat consists of saliva resistant acetylated acid mucopolysaccharides containing hyaluronic acid with carboxyl polyanions. Intense activities of acid phosphatase, glucose-6-phosphatase, and ATPase, and moderate activities of nonspecific esterase and lipase are localized at the brush border. The functional significance of the surface carbohydrates and the hydrolytic enzymes has been discussed in relation to digestion and absorption of nutrients. © 1978, Cambridge University Press. All rights reserved.