What is "voragonema"

Voragonema is a genus of jellyfish belonging to the family Rhopalonematidae. The genus comprises four species. Unlike most hydromedusae, these jellyfish do not have a sessile stage. Rather, they spend their entire lives in the water column as plankton. Centripetal expansions protruding from the ring canal is a characteristic that separates this genus from other genera in the family Rhopalonematidae.