Largest carybdeid when full grown, up to 230 mm bell height recorded, but also fertile 1/4 as high. Bell nearly round in cross-section; elongate, height variously reported as 1.2 to 1.7 times width, even twice, proportionaly higher when large; hyaline (glassy), exumbrella lacking nematocyst warts at least when young (some doubt); apex bluntly flat-topped. Pedalia long, scalpel- or lancet-shaped; pedalial canal bent through right-angle at top without diverticulum. Contracted tentacle thick, banded, up to about 1.5 times bell height, tapering for basal ca. 1/6. Rhopalial niche deep, entrance T-shaped, conspicuous, slightly more than 1/4 up from bell edge; entrance with one bluntly pointed flap above and none or two shallow below, their bases together forming an equilateral triangle with the point downwards; possibly shorter and not meeting in young individuals, longer and meeting together in larger ones, but this perhaps an artifact of preservation; possibly some variation in lip-shape. Velarium with 24 short, branching, non-anastomosing velar canals. Manubrium short, lips slightly recurved. Gastric cirri in 4 deeply crescent-shaped areas; a stomach pouch in each gap between leading into radial sinus. One half-gonad on each side of each radial sinus.
Color: jelly notably clear, endoderm translucent, milky white; gastric cirri and flexible parts of tentacles pink to yellow-pink; sensory knobs of rhopalia dull ochre, the ocelli deep brown to nearly black.
Dangerous, sting painful, causing lasting problems but not lethal.
(Mostly after Mayer, 1910; Kramp, 1961; Uchida, 1970).