Box jellyfish classes Cubozoa are cnidarian invertebrates distinguished by their box-like i.e. cube-shaped body. Some manner of box jellyfish realize potent venom introduced by contact with their tentacles. Stings from some species, including Chironex fleckeri, Carukia barnesi, Malo kingi, together with a few others, are extremely painful & often fatal to humans.
The medusa do of a box jellyfish has a squarish, 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 so-called as a velarium which restricts the bell's aperture and creates a effective jet when the bell pulsates. As a result, box jellyfish can stay on more rapidly than other jellyfish; speeds of up to 6 metres 20 ft per minute have been recorded.
In the center of the underside of the bell is a mobile appendage called the manubrium which somewhat resembles an elephant's trunk. At its tip is the mouth. The interior of the bell is requested as the gastrovascular cavity. It is divided up by four equidistant septa into a central stomach and four gastric pockets. The eight gonads are located in pairs on either side of the four septa. The margins of the septa bear bundles of small gastric filaments which combine nematocysts and digestive glands and assist to subdue prey. regarded and indicated separately. septum is extended into a septal funnel that opens onto the oral surface and facilitates the flow of fluid into and out of the animal.
The box jellyfish's nervous system is more developed than that of many other jellyfish. They possess a nerve ring around the base of the bell that coordinates their pulsing movements, a feature found elsewhere only in the crown jellyfish. Whereas some other jellyfish have simple pigment-cup ocelli, box jellyfish are unique in the possession of true eyes, ready with retinas, corneas and lenses. Their eyes are classification in clusters called rhopalia, located in pockets halfway up the outer, flat surfaces of the bell. regarded and identified separately. contains two rhopalial ocelli with lenses, one directed upwards and the other downwards and inwards towards the manubrium. This lets the animal to see particular points of light, as opposed to simply distinguishing between light and dark. Box jellyfish also have twenty ocelli simple eyes that do non form images, but detect light and dark; they therefore have a total of twenty-four eyes. most the rhopalia are statoliths which detect gravitational pull and help the animal to orient itself.
Box jellyfish also display complex, probably visually-guided behaviors such(a) as obstacle avoidance and fast directional swimming. Research indicates that, owing to the number of rhopalial nerve cells and their overall arrangement, visual processing and integration at least partly happen within the rhopalia of box jellyfish. The complex nervous system maintain a relatively contemporary sensory system compared to other jellyfish, and box jellyfish have been referenced as having an active, fish-like behavior.
Depending on species, a fully grown box jellyfish can degree up to 20 cm 8 in along each box side 30 cm or 12 in in diameter, and the tentacles can grow up to 3 m 10 ft in length. Its weight can2 kg +1⁄2 lb. However, the thumbnail-sized Irukandji is a box jellyfish, and lethal despite its small size. There are approximately 15 tentacles on each corner. Each tentacle has approximately 500,000 cnidocytes, containing nematocysts, a harpoon-shaped microscopic mechanism that injects venom into the victim. many different kinds of nematocysts are found in cubozoans.