Gregarines
A live specimen of a septate (or cephaline) gregarine showing the distinctive "head"-like section of the trophozoite containing the epimerite at its anterior end. Septate gregarines are intestinal parasites of arthropods.
Scientific classification
Domain:	Eukaryota
Kingdom:	Chromalveolata
Superphylum:	Alveolata
Phylum:	Apicomplexa
Class:	Conoidasida
Subclass:	Gregarinasina
Order:	Archigregarinorida
Families
Exoschizonidae Selenidioididae

The Archigregarinorida are an order of parasitic protozoa in the phylum Apicomplexa

This order was redefined by Levine in 1971.^[1]

The order currently consists of two families - Exoschizonidae and Selenidioides. The family Exoschizonidae contains one genus - Exoschizon - which has one species. The family Selenidioididae has three genera: Merogregarina with one species, Meroselenidium with one species and Selenidioides with 11 species.