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 on Koror. The golden jellyfish population in Big Jellyfish Lake, Koror did not seem to be affected. The reason for this was not clear, but Big Jellyfish Lake experienced lower temperature increases than the other lakes and there was experimental evidence that the golden jellyfish medusa from Big Jellyfish Lake were more tolerant of higher temperatures. Although Clear Lake did not seem to have experienced the complete medusa population die-off that Jellyfish Lake did in 1998, the golden jellyfish medusae in Clear Lake are not always present. When conditions are not favorable for the short lived medusa stage or for