A cuboid medusa 1 cm or more across, with three tentacles at each corner. Bell slightly lower than square in side view, flattened apically, exumbrella covered sparsely with small nematocyst warts. Velarium about 1/6 width of base of bell, with 6 unbranched velar canals per quadrant, triangular in outline. Rhopalia on short stalks in wide niches bordered by rim, about 1/4 to 1/5 up bell. Stomach short, with 4 wide gastrovascular pouches leading into radial canals; manubrium reaching nearly to base of bell; it and mouth cross-shaped in section. Gastric cirri small, tapering, "brush-shaped", arising from a short stalk in each interradial corner of stomach. Three separate pedalia on each corner of bell, length of each about half height of bell, laterally narrow, each with a single tentacle about 2.5 times its length when contracted. Gonads 4, lamellar, each spanning both sides of each radial sinus, extending vertically from bell margin nearly to apex and when mature each reaching neighbour laterally; broods planula larvae.
Color: Medusa including gonads a uniform light yellowish-brown.
(After Conant, 1898; Mayer, 1910; and Werner, 1984).