Barrel jellyfish. Black Sea. Georgia. Rhizostoma pulmo, commonly known as the barrel jellyfish, the dustbin-lid jellyfish or the frilly-mouthed jellyfish, is a scyphomedusa in the family Rhizostomatidae. It is found in the northeast Atlantic, and in the Adriatic, Mediterranean Sea, Black Sea and Sea of Azov. It is also known from the southern Atlantic off the western South African coast and into False Bay. They are found typically in late summer, and early fall in increased populations which are known as blooms. This is due to higher temperatures and other environmental factors such as wind.