Description of Actinocephalidae

Stenophorid gregarines, epimerite symmetrical, with or without appendage, syzygy (association) late, frontal; gametocysts without sporoducts, generally dehiscing by simple rupture; oocysts biconical, cylindro-biconical, or irregular, simple or spiny; in intestine of arthropods, chaetognaths, or chordates; mostly intestinal parasites of insects and centipedes, some are reported from arrow worms and pelagic tunicates.