Family: Some oral structures confined to shallow oral pit; several oral dikinetids or polykinetids to left of cytostome; often without obvious right paroral kinetids (Illustrated Guide, 1985).
Genus: Buccal cavity and internal atrium large; a well-developed cytopharyngeal basket present; the atrial depression is in two parts, the outer shallow region and an inner deep region leading to the cytostome (Carey, 1992). Like Nassula, but cyrtos has smaller opening (How to know the protozoa, 1979).
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125 x 45 μm
150 x 52 μm
65 x 25 μm