Tend to be small (usually <10 mm long and 1 mm wide). Body is usually small, short, and slender. The pharynx is an eversible tube with cuticular lining that is usually armed with a dorsomedial tooth. Two pairs of tentacular cirri are present. Dorsal cirri are variable and may alternate between long and short and may be articulated or moniliform, smooth, or irregularly wrinkled.

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