Box jellyfish box-like bell, from which its name is derived. From each of the four lower corners of this hangs a short pedalium or stalk which bears one or more long, slender, hollow tentacles. The rim of the bell is folded inwards to form a shelf known as a velarium which restricts the bell's aperture and creates a powerful jet when the bell pulsates. As a result, box jellyfish can move more rapidly than other jellyfish; speeds of up to per minute have been recorded. In the center of the underside of the bell is a mobile appendage called the manubrium which
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