A saucer-shaped hydromedusa with a well-developed velum. Has 80 or more narrow, unbranched radial canals (sometimes only 60) which extend all the way to the margin of the bell. The slender gonads run along most of the length of the radial canals and do not hang down. Gonads are bluish in males, rosy in females. Has one to several unbranched tentacles for each radial canal. All tentacles extend from the margin of the bell. The tentacles are in a single row around the margin of the bell, can be extended long or held very short (as in the photo above), and are usually not all of the same size. The manubrium is short and wide, with ruffled edges ("lips") but can be closed all the way when prey is inside. Usually colorless. Diameter up to about 8 cm.