Jellyfish canal. Cilia in these canals circulate the fluid in a regular direction. The box jellyfish is largely similar in structure. It has a squarish, box-like bell from each of the four lower corners of which hang a short pedalium or stalk which bears one or more long, slender 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, allowing box jellyfish to swim faster than true jellyfish. Hydrozoans are also similar, usually with just four tentacles at the edge
Atolla jellyfish the “alarm jelly”. It is believed that the purpose of these flashes is to attract a bigger predator than the one that was currently attacking it (Herring 2004). It is an attempt to scare the predator that is currently attacking it with a larger predator that could possibly prey on the predator attacking it. There has been evidence that "Atolla wyvillei" is threatened by shrimp (Moore,1993). A close relative of "Atolla" species, the crown jellyfish is eaten as a delicacy in Japan (Seaunseen, 2014). Atolla jellyfish Atolla wyvillei, also known as the Atolla jellyfish or Coronate medusa, is a species