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Secretory granules produced by the Mehlis' gland and by the wall of the distal ootype in Schistosoma haematobium females, were examined at the ultrastructural level by means of several cytochemical methods. Strong staining, due to a relatively high percentage of carbohydrates in the granules, was observed in polymethacrylate sections treated with a phosphotungstic acidhydrochloric acid mixture at pH ≈ 0.5. Staining with ferric chloride-mixed-diamine mixtures (the LID and the HID reaction) showed no detectable level of oligosaccharide carboxyl and sulphate groups. A periodic acid-thiocarbohydrazide-silver proteinate reaction which was performed on epoxy sections, revealed a relatively high level of glycopyranosidic 1,2-diol groups in the granules. These results as well as the sensitivity of the secretory granules to the proteolytic action of papain indicated that the secretions produced by the Mehlis' gland and by the ootype wall were neutral glycoproteins.