Woodworth, 1899
Body broad and very flat; mouth and proboscis pore united; rhynchocoel extends almost to hind end of body, with wall containing meshwork of interwoven circular and longitudinal muscle fibres; intestinal diverticula numerous, much branched and with ventral branch extending below lateral nerve cords; spermaries in two elongated groups or in irregular rows behind brain.
Planktonemertes vanhoeffeni