Family: Oral region flat only at apex; body kineties abut on oral region (Illustrated Guide, 1985).
Genus: Ovoid or cylindrical in shape; anterior rounded or drawn out into an elongate snout; cytostome apical; dorsal brush present, formed by paired kinetosomes (Carey, 1992). Oral region truncated with flat membranous region forward of oral dikinetids (Illustrated Guide, 1985).