Jellyfish jellyfish, because jellyfish feed on plankton, which includes fish eggs and larvae. Jellyfish form a component of jelly-falls, events where gelatinous zooplankton fall to the seafloor, providing food for the benthic organisms there. In temperate and subpolar regions, jelly-falls usually follow immediately after a bloom. Most jellyfish are marine animals, although a few hydromedusae inhabit freshwater. The best known freshwater example is the cosmopolitan hydrozoan jellyfish, "Craspedacusta sowerbii". It is less than an inch (2.5 cm) in diameter, colorless and does not sting. Some jellyfish populations have become restricted to coastal saltwater lakes, such as Jellyfish Lake in Palau. Jellyfish
Marine Biological Laboratory disease. Other marine organisms draw neuroscientists and neurobiologists to the MBL each summer, where a history of research into sensory physiology and behavior has been established. Haldan Keffer Hartline, an MBL summer investigator in the 1920s and early 1930s, uncovered several basic mechanisms of photoreceptor function through his studies on the horseshoe crab. Hartline shared the 1967 Nobel Prize with summer MBL colleague George Wald, who described the molecular basis of photoreception by showing that the light-sensitive visual pigment molecules consist of a slightly modified form of vitamin A coupled to a protein. Another long-term summer investigator, Stephen W. Kuffler,