SUMMARYThe ultrastructure of microbodies in zoospores, hyphae and developing sporangia was studied inMonoblepharellasp. Catalase activity in these organelles was demonstrated with the diaminobenzidine cytochemical technique. In zoospores elongate microbodies lay adjacent to lipid globules, ribosomal aggregations, and rumposomes. Hyphal microbodies varied in morphology and were either oval, elongate, reticulate or ring shaped. Microbodies in developing sporangia were elongate, branched and closely appressed to lipid globules. This study supports the validity of the microbody-lipid-globule complex as a possible phylogenetic marker in Chytridiomyoetes.