ULTRASTRUCTURE AND DEVELOPMENT OF MICROSPORIDIUM-OVOIDEUM (THELOHAN, 1895) SPRAGUE, 1977, A MICROSPORIDIAN PARASITE OF THE RED BAND FISH (CEPOLA-MACROPHTHALMA L) - REDESCRIPTION OF THE ORGANISM AND REASSIGNMENT TO THE GENUS MICROGEMMA, RALPHS AND MATTHEWS 1986

A study of the ultrastructure and life cycle of Microsporidium ovoideu m, a hepatic parasite of Cepola macrophthalma, has been carried out. T his parasite caused xenomas up to 1-2 mm, which consisted of a hypertr ophic cell, filled with different stages of the parasite and rests of the host cell organelles, which had a pychnotic hypertrophic nucleus. Merogonic stages consisted of round multinucleate plasmodia that divid ed by plasmotomy or exogenous budding, and were not enclosed by any me mbrane. Sporogonic plasmodia divided by exogenous budding to produce s poroblast mother cells which after a binary fission become sporoblasts . Sporogony occurs in direct contact with host cytoplasm. The spores, which are ovoid and uninucleate, show a posterior vacuole in the poste rior third of the spore and an isofilar polar filament with 6-8 coils. The characteristic features permit a reassignation of this microspori dium into the genus Microgemma and give a new combination: Microgemma ovoidea.