The duct was reacted histochemically to identify glycoproteins and several enzymic activities. Neutral mucosubstances were detected in the entire cytoplasm of the principal cells, and acid glycoproteins were identified only in a thin apical zone corresponding to the glycocalyx. Lysosomal enzymes were demonstrated as cytoplasmic granules, whereas endogenous peroxidase was diffusely distributed throughout the entire cytoplasm of the epithelial cells. 17 beta- and 3 beta-hydroxysteroid dehydrogenases and prostaglandin-synthetase reactivity were intense in all epithelial cells.