Ultrastructural data on sporogony of the coccidian parasite <em>Calyptospora spinosa</em> from the liver of the Amazonian fish, <em>Crenicichla lepidota</em> Heckel.

The article discusses about some ultra-structural features of the sporogony of Calyptospora spinosa, a species recently described in an estuarine Amazonian fish. Livers of Crenicichla lepidota Heckel (Teleostei, Cichlidae) collected from the estuarine Amazon region near Belem, Brazil, infected with C. spinosa were used in this study. Subsequently, an internal differentiation of cytoplasmic membranes gave rise to a network which fused and surrounded each nucleus, forming the future plasmalemma of the uninucleate sporoblast.