Thimble jellyfish Thimble jellyfish The thimble jellyfish ("Linuche unguiculata") is a species of cnidarian found in the neotropical Atlantic Ocean. It is a tiny jellyfish with a straight-sided, flat-topped bell. This jellyfish is the most common cause of seabather's eruption, a reaction caused by the injection of juvenile jellyfish nematocysts into human skin. The medusa of the thimble jellyfish has straight sides with sixteen grooves, and a flat top. The coronal groove between the top and sides provides flexibility. The margin of the bell has sixteen lappets (folds), the niches between these bearing alternately rhopalia (sense organs) and short tentacles (eight of
Jellyfish Lake for Clear Lake on Eil Malk) does not begin until the late afternoon. Hamner and Dawson proposed that the difference is caused by evolutionary change driven by the jellyfish-eating anemones ("Entacmaea medusivora") that inhabit the eastern regions of Jellyfish Lake and Clear Lake. The jellyfish instinctively avoid shadows and in the morning with the shadows on the eastern end the jellyfish also avoid the anemones. By moving east to west in the early afternoon the jellyfish avoid the time of day when the setting sun would eliminate shadows on the lake in the eastern end and thereby avoid the anemones