Aseptatorina Blastogregarinorina Septatorina The Eugregarinorida are the most large and diverse order of gregarines — parasitic protists belonging to the phylum Apicomplexa.

The surface is inscribed by 90-300 epicytic folds resulting in stiff cells that are capable of gliding motility.

However, a revision of the morphology of eugregarines has been proposed: they possess only the epimerite and epicytic crests (unlike the genuine mucron and longitudinal folds of Archigregarinorida).

[2] Intestinal eugregarines are separated into septate (mostly terrestrial) and aseptate (mostly marine) gregarines, depending on whether the trophozoite cell is superficially marked by a transverse septum.

The transmission of the parasite to new host usually takes place by oral ingestion of oocysts in both aquatic and terrestrial environments.

The gamonts may not be equal in size: in this case the smaller is referred to as the satellite and the larger as the primite.

The gametes fuse in pairs and give rise to a zygote — the only diploid stage in the life cycle.