Order: Hypostomial frange not extensive (Carey, 1992). Medium to large, some >100 μm long; oral polykinetids only next to left rear of cytostome; large cyrtos has complete palisade of nematodesmata (Illustrated Guide, 1985). Suborder: With deep oral cavity (Illustrated Guide, 1985). Family & Genus: Usually large ( >200 μm long or more); preoral groove much expanded (Illustrated Guide, 1985).

100 μm 200 μm 300 μm; x 200