Box jellyfish box jellyfish's nervous system is more developed than that of many other jellyfish. They possess a nerve ring around the base of the bell that coordinates their pulsing movements, a feature found elsewhere only in the crown jellyfish. Whereas some other jellyfish have simple pigment-cup ocelli, box jellyfish are unique in the possession of true eyes, complete with retinas, corneas and lenses. Their eyes are set in clusters called rhopalia, located in pockets halfway up the outer, flat surfaces of the bell. Each contains two rhopalial ocelli with lenses, one directed upwards and the other downwards and inwards towards the
Thimble jellyfish eruption in the Caribbean and the Gulf of Mexico. This is an itchy rash of small red papules that develops in the areas that were covered by the bather's swimwear or hair. The condition does not occur immediately, but after the bather has showered or the skin has dried, killing the jellyfish larvae which react by discharging their stinging cells. In Florida, most cases occur between March and August. A similar condition occurs on the east coast of North America after exposure to the larvae of the sea anemone "Edwardsiella lineata". Thimble jellyfish The thimble jellyfish ("Linuche unguiculata") is a