(Péron and Lesueur, 1810)
Bell steeply conical to domed, apex pointed; coronal groove prominent; height to 35 cm, diameter to 25 cm; height:diameter ratio variable. Mesoglea thick, rigid. Exumbrella smooth. Marginal lappets 16 (8 rhopalar + 8 tentacular), uniform, elongate-rounded, thick basally, thinning to margin. Rhopalia 4, in deep clefts between lappets. Tentacles 12, three between each rhopalium and next, thick, tapering; in life held pointing either aborally or orally but all in same direction, more or less straight. Coronal muscle broad, longitudinally folded. Stomach large, occupying whole of upper part of central dome; communicating with peripheral gastrovascular sinus through 4 perradial openings, numerous large gastric cirri projecting through each one. Gonads 8, disposed in 4 U-shaped groups looping across lower 2/3 of bell, straddling interradial septa.
Color: stomach and manubrium deep reddish-brown to brown; exumbrella and sub-surface tissues colorless.
(After Mayer, 1910; Russell, 1970; Mianzan, 1989).