The absorptive surface of Moniliformis dubius (Acanthocephala). II. Functional aspects

The functional nature of the acanthocephalan absorptive surface was further elucidated by a series of morphological and cytochemical studies with the electron microscope. The use of lanthanum nitrate and ruthenium red in fixatives and Thorotrast staining en bloc and on epoxy thin sections provided information about the surface coat and the surface crypts. Acid phosphatase was localized in the lumina of the crypts and in the five lysosomal types. In vitro studies utilizing ferritin, Thorotrast and horseradish peroxidase implicated the surface crypts in the digestion and/or uptake of large molecules. A consideration of the evidence suggests that these crypts are highly selective and specific in their function.