A decade ago this summer, at the Marine Biological Laboratory, Jocelyn Malamy watched jellyfish cells “walk” toward each other to close a wound for the first time.  An associate professor in Molecular Genetics and Cell Biology at the University of Chicago, Malamy had received transparent, dime-sized medusae of the species Clytia hemisphaerica from Evelyn Houliston’s lab at the Marine Observatoire in Villefranche. The medusa, the free-swimming form most people picture when they hear the term jellyfish, is only one stage of the animal’s life cycle. “ Clytia are hydrozoans, so mostly they exist as polyp colonies that grow along the surface of rocks or on docks or the underside of underwater leaves,” says Malamy. At some point in their life cycle, the colony will start releasing baby medusae. In this way, Clytia’s  medusae forms are much like flowers, while the polyps are like the shrubs that produce them.…