Characteristics of the Family (from Kramp 1961)
Rhizostomes with mouth-arms dichotomous and triangular or three-winged. A network of anastomosing canals communicate with the central gastral cavity in several places between the radial canals. Rhopalar pits smooth, without radial folds. Subgenital ostia without papillae.
With annular subumbrellar muscles. With eight rhopalar radial canals. With ring canal. With a continuous genital porticus. Subgenital ostia very broad. Arm-disk quadratic, with four primary canals.
With short, pyramidal, three-winged mout-arms; with filaments on the arm-disk.