Brinkmann, 1917
Body broad and generally much flattened; posterior end usually with caudal fin; rhynchocoel musculature comprising meshwork of interwoven circular and longitudinal fibres; dorsal vessel extends almost full length of body; dorsal anastomosis of cephalic blood vessels present; intestinal diverticula much divided, usually with ventral branch; spermaries in two longitudinal groups or rows immediately behind brain.
Genus Planktonemertes