Unlike the other members of the order, members of the family Tetraplatidae have no tentacles nor bell but are worm-like in shape. The body is divided by a transverse groove beside which there are four muscular flaps or lappets used for swimming. Each of these contains two sense organs. In one species there are four flying buttresses alternating with the lappets. The gonads are epidermal and have lobes either side of the groove.Order Narcomedusae - Haeckel, 1879 The Hydrozoa Directory. Retrieved 2011-11-07.
