Crown jellyfish Crown jellyfish Crown jellyfishes are the six families of true jellyfish that belong to the order Coronatae. They are distinguished from other jellyfish by the presence of a deep groove running around the umbrella, giving them the crown shape from which they take their name. Many of the species in the order inhabit deep sea environments. Crown jellyfish are able to make light through bioluminescence. When they are touched, their bells will light up. Otherwise, the bell of a crown jellyfish will look transparent when undisturbed. When they are attacked, crown jellyfish are able to startle, mislead, and distract their
Helmet jellyfish jellyfish is found in depths up to 7,000 m and is adapted to its dark environment. A weight of up to a ton per square centimeter presses upon the animals, which live in deep sea. At night the helmet jellyfish leaves the depths and swims up toward its food, plankton. With full stomach it turns from the surface back to the depths. Other deep-sea inhabitants feed upon its faeces. Helmet jellyfish reach a body size of up to 30 cm. They consist 90% of water, the rest being tissue and gelatinous mass, which give the animals their form. They light