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 in the afternoon. The moon jellyfish do not have an organized horizontal migration pattern. At night they migrate to the surface presumably to feed. The copepods that make up a significant portion of the moon jellyfish diet in Jellyfish Lake also migrate to the surface at night. Beginning in about the fall of 1998, a precipitous decline in the golden jellyfish medusa population was detected in Jellyfish Lake. By December 1998, the medusa population had declined to zero. Based on their extensive investigation of the disappearance of the golden jellyfish medusae, Dawson et al. determined that the most likely cause