Aurelia

Aurelia, one of the commonest of the British jelly-fish. It belongs to the order Rhizostomidae of the Acraspedote section of Hydrozoa. The adult consists of a rounded disc, convex above and flat below; from the upper part of the disc a tube (the manubrium) is suspended; the mouth is at the lower end, and it opens at the upper end to the "gastric cavity" in the four lobes of which the food is digested. From each lobe a branching canal runs to the margin of the disc, while eight canals run directly to the large canal round the circumference. Four oral tentacles surround the mouth. On the margin of the disc are eight sense organs known as "tentaculocysts" or "rhopalia"; a pair of olfactory pits is associated with each of these. A genital gland occurs in each of the four gastric lobes. The remarkable development found in this genus has been described under Acraspedae. Aurelia aurita is the commonest English species.