In the world of the medusae

Impressive creatures in the ocean captivate us. They are interesting to look at, but it is better not to come into contact with some of them, as their venom can be deadly. Medusae, also known as jellyfish, can be found in all the world's oceans, and in some aquariums you can observe them safely. Jellyfish and sea jellies are the informal common names given to the medusa-phase of certain gelatinous members. Jellyfish are mainly free-swimming marine animals with umbrella-shaped bells and trailing tentacles, although a few are anchored to the seabed by stalks rather than being mobile.