Two basic types of spore wall structures were observed in ultrastructural examination of Schizoplasmodiopsis micropunctata, Schizoplasmodiopsis pseudonendospora, Schizoplasmodipsis reticulata, and Schizoplasmodipsis vulgare. The spores of S. micropunctata, S. pseudoendospora, and S. vulgare had walls bearing electron-dense protrusions, while those of S. reticulata had walls with irregular thickenings. Prominent cytoplasmic features included 2 types of vesicles and electron-dense bodies studded with ribosomes. The ameboid phase of all species lacked the electron-dense bodies and, unlike the dormant phases, did not have mitochondrial surfaces covered with ribosomes.
