"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, complete with retinas, corneas and lenses. Their eyes are set in clusters called rhopalia, located in pockets halfway up the outer, flat surfaces of the bell. Each contains two rhopalial ocelli with lenses, one directed upwards and the other downwards and inwards towards the"
"to form the manubrium, a central organ with the mouth at its tip, resembling an elephant's trunk. Some have numerous manubrial outgrowths, well-armed with cnidocytes and mucus-secreting cells; others have the central manubrial mouth closed, instead making use of secondary mouths at the side of the manubrium. These adaptations give the jellyfish a large surface area with which to collect large quantities of planktonic organisms. It can trap plankton from the water currents it produces by pulsating. Jellyfish fished commercially and used for food come from this order. Members of the Semaeostomeae are known as ""flag-mouth jellies"" and are large"
"jellyfish. They have an elongate manubrium composed of four oral arms. The edge of the bell bears flaps known as lappets and in the niches between these, there are usually eight rhopalia (sensory organs). Sometimes there are also hollow marginal tentacles. The stomach is subdivided into four gastric pouches, with the four gonads situated on the oral walls of the pouches. Some semaeostomids are suspension feeders, but others supplement this with prey such as small fish, crustaceans, worms and other jellyfish. The pulsating action of the bell is linked by a nerve ring to the sensory inputs received by the"
"to their natural habitat. The jellyfish is translucent, usually about in diameter, and can be recognized by its four horseshoe-shaped gonads, easily seen through the top of the bell. It feeds by collecting medusae, plankton, and mollusks with its tentacles, and bringing them into its body for digestion. It is capable of only limited motion, and drifts with the current, even when swimming. The genus ""Aurelia"" is found throughout most of the world's oceans, from the tropics to as far north as latitude 70°N and as far south as 40°S. The species ""Aurelia aurita"" is found along the eastern Atlantic"
"Haliclystus auricula Haliclystus auricula is a stalked jellyfish found in the Northern hemisphere. It is the type species for its genus. In 2010, Natural England, ""The Guardian"" and the Oxford University Museum of Natural History ran a competition asking members of the public to provide a common name for this species. The name ""Kaleidoscope Jellyfish,"" submitted by Kepler Petzall, was eventually chosen. Runner-up names included Fractal flower jellyfish and Mermaid's trumpet jellyfish. ""H. auricula"" is 2-2.5 cm tall with the stalk accounting for half of the height of the organism. The remainder of the organism is shaped like a funnel,"
"jellyfish, ""Stomolophus meleagris"", along the southern Atlantic coast of the United States and in the Gulf of Mexico for export to Asia. Jellyfish are also harvested for their collagen, which is being investigated for use in a variety of applications including the treatment of rheumatoid arthritis. Aristotle stated in the ""Parts of Animals"" IV, 6 that jellyfish (sea-nettles) were eaten in winter time in a fish stew. In some countries, such as China, Japan, and Korea, jellyfish are a delicacy. The jellyfish is dried to prevent spoiling. Only some 12 species of scyphozoan jellyfish belonging to the order Rhizostomeae are"
"Helmet jellyfish The helmet jellyfish (""Periphylla periphylla"") is a luminescent, red-colored jellyfish of the deep sea, belonging to the order Coronatae of the phylum Cnidaria. It is the only species in the monotypic genus ""Periphylla."" ""P. periphylla"" represents an exception, very rarely found in the phylum ""Cnidaria"": the medusae do not go through a polyp stage, thus presenting a ""holopelagic"" life cycle. The medusae strew fertilized eggs in open water and these develop directly into medusae, whose development rests entirely upon the egg's high yolk supply. The ephyra stage common among other jellyfish is not observed in ""P. periphylla"". The"
"the word ""fish"" with its connotations of an animal with a backbone, though shellfish, cuttlefish and starfish are not vertebrates either. In scientific literature, ""jelly"" and ""jellyfish"" have been used interchangeably. Many sources refer to only scyphozoans as ""true jellyfish"". The term jellyfish broadly corresponds to medusae, that is, a life-cycle stage in the Medusozoa. The American evolutionary biologist Paulyn Cartwright gives the following general definition: The Merriam-Webster dictionary defines jellyfish as follows: Given that jellyfish is a common name, its mapping to biological groups is inexact. Some authorities have called the comb jellies and certain salps jellyfish, though other"
"Rhopilema verrilli Rhopilema verrilli, or mushroom cap jellyfish, is a species of jellyfish in the family Rhizostomatidae. They are cnidarian invertebrates distinguished by their mushroom-shaped medusae. The species does not have any tentacles; however, they still have stinging cells, called nematocysts, within their bells, which can produce mild stings to humans. “Mushroom cap jellyfish” and “sea mushroom jellyfish” are common names for the rare ""Rhopilema verrili"". Their common name refers to the shape of the medusa, which resembles a mushroom cap. ""Rhopilema verrilli,"" originally ""Nectopilema verrilli"", was named by Fewkes (1887) after a specimen found in the New Haven Harbor"
"sexually. Males release sperm through their mouth into the water column and this is received into the female's mouth, where fertilization occurs. Development has to occur pretty quickly, as the lifespan of a jellyfish is only a few months. The eggs develop either inside the female, or in brood pouches located on the oral arms. They also aid in the capture and ingestion of food, and may contain stinging cells. Oral arm An Oral arm is an anatomical structure of ""true"" sea jellies (or Scyphozoans), which belong to the class Scyphozoa. Oral arms characterize Semaeostomeae, an order of large jellyfish."
"Rhizostoma pulmo Rhizostoma pulmo, commonly known as the barrel jellyfish, the dustbin-lid jellyfish or the frilly-mouthed jellyfish, is a scyphomedusa in the family Rhizostomatidae. It is found in the northeast Atlantic, and in the Adriatic, Mediterranean Sea, Black Sea and Sea of Azov. It is also known from the southern Atlantic off the western South African coast and into False Bay. It is common in the Irish Sea. It typically is up to in diameter, but can exceptionally reach , making it the largest jellyfish in British waters (""Cyanea capillata"" reaches an even larger size, but is generally smaller in"
"Britain). It is a favourite food of the leatherback turtle. Rhizostoma pulmo Rhizostoma pulmo, commonly known as the barrel jellyfish, the dustbin-lid jellyfish or the frilly-mouthed jellyfish, is a scyphomedusa in the family Rhizostomatidae. It is found in the northeast Atlantic, and in the Adriatic, Mediterranean Sea, Black Sea and Sea of Azov. It is also known from the southern Atlantic off the western South African coast and into False Bay. It is common in the Irish Sea. It typically is up to in diameter, but can exceptionally reach , making it the largest jellyfish in British waters (""Cyanea capillata"""
"angles, it bears a somewhat eerie resemblance to a human head or skull. Since it is virtually transparent, the creature is nearly impossible to see in its habitat, posing particular danger to swimmers. When the jellyfish are swimming, the tentacles contract so they are about 15 cm long and about 5 mm in diameter; when they are hunting, the tentacles are thinner and extend to about 3 m long. The tentacles are covered with a high concentration of stinging cells called cnidocytes, which are activated by pressure and a chemical trigger; they react to proteinous chemicals. Box jellyfish are day"
"Rhizostomae Rhizostomae or Rhizostomeae is an order of jellyfish. Species of this order have neither tentacles nor other structures at the bell's edges. Instead, they have eight highly branched oral arms, along which there are suctorial minimouth orifices. (This is in contrast to other scyphozoans, which have four of these arms.) These oral arms become fused as they approach the central part of the jellyfish. The mouth of the animal is also subdivided into minute pores that are linked to coelenteron. Jellyfish species fished on a commercial basis for human consumption (both as a delicacy and for use in traditional"
"has several moderately long tentacles along the bell. The bell is around 20–174 mm in diameter. It also has a single long tentacle called a hypertrophied tentacle. This hypertrophied tentacle has several purposes, including aid in predation and aid in reproduction. These jellyfish do not have a digestive system, a respiratory system, a circulatory system or a central nervous system. Not having a central nervous system means that it lacks a brain. ""Atolla wyvillei"" is found all over the globe in the deep ocean. There has been evidence of them found in The deep ocean is a depth from 1,000"
"Oral arm An Oral arm is an anatomical structure of ""true"" sea jellies (or Scyphozoans), which belong to the class Scyphozoa. Oral arms characterize Semaeostomeae, an order of large jellyfish. The oral arms (of which there are usually four) are located around the mouth and hold the stinging cells, or cnidocysts, which are used to inject potential prey (or potential predators) with venom. These four long oral arms, hang from the center of the underside, where the mouth of the jellyfish is located. In most cases, 24 other, thinner extensile tentacles hang from the rim of the bell. Jellyfish reproduce"
"Melon-headed whale The melon-headed whale or melon-headed dolphin (species ""Peponocephala electra""; other names are many-toothed blackfish, ""melon whale"" and electra dolphin) is a cetacean of the oceanic dolphin family (Delphinidae). It is closely related to the pygmy killer whale and pilot whale, and collectively these dolphin species are known by the common name blackfish. It is also related to the false killer whale. The melon-headed whale is widespread throughout the world's tropical waters, although not often seen by humans because it prefers deep water. The melon-headed whale's head is a rounded cone giving the animal its common name. The body"
"Amphipoda, regularly ride on its bell and even steal food from its oral arms and tentacles. The lifecycle of this jellyfish is well known, because it is kept in culture at the Monterey Bay Aquarium. It alternates between a benthic stage attached to rocks and piers that reproduces asexually and the planktonic stage that reproduces sexually in the water column; both males and females occur in the plankton. A smaller jellyfish, ""Cotylorhiza tuberculata"", typically found in warmer water, particularly in the Mediterranean Sea, is also popularly called a fried egg jellyfish. Phacellophora camtschatica Phacellophora camtschatica, commonly known as the fried"
"a problem than ""S."" ""meleagris"". The mushroom jellyfishes are served pickled, or dried out into paste in Asian countries such as China and Japan. The taxon for ""Rhopilema"" has not yet been assessed for the IUCN Red List. Rhopilema verrilli Rhopilema verrilli, or mushroom cap jellyfish, is a species of jellyfish in the family Rhizostomatidae. They are cnidarian invertebrates distinguished by their mushroom-shaped medusae. The species does not have any tentacles; however, they still have stinging cells, called nematocysts, within their bells, which can produce mild stings to humans. “Mushroom cap jellyfish” and “sea mushroom jellyfish” are common names for"
"the Cambrian of the Marjum Formation in Utah, USA, c. 540 mya. The main feature of a true jellyfish is the umbrella-shaped bell. This is a hollow structure consisting of a mass of transparent jelly-like matter known as mesoglea, which forms the hydrostatic skeleton of the animal. 95% or more of the mesogloea (the tissue that functions as a hydro-static skeleton) consists of water, but it also contains collagen and other fibrous proteins, as well as wandering amoebocytes which can engulf debris and bacteria. The mesogloea is bordered by the epidermis on the outside and the gastrodermis on the inside."
"to vary across the different species. Species in this genus also have eight large pads known as anchors located between the arms. These vary in size and shape and currently play in important role in differentiating one species from another. Some, but not all, species in this genus have prominent white nematocyst clusters. The 'stalk' or peduncle in this genus is four chambered. At least one group of scientists have suggested that the taxonomy of this genus needs to be revised. Haliclystus Haliclystus is a genus of stalked jellyfish that contains 11 species and one nomen nudum (""Haliclystus sanjuanensis""). It"
"into young (male or female) ""Pelagia noctiluca"" jellyfish. These organisms have a well-developed manubrium, a proboscis-like structure bearing the mouth and four long oral arms. Also the mesoglea, or jelly, is relatively thickened and well developed in this species. Sense organs, known as rhopalia in the scyphomedusae, are located around the umbrella margin in notches and alternate between tentacles. Cnidae are present in the epidermis and gastrodermis of the umbrella, as well as on the tentacles. ""P. noctiluca"" has eight marginal tentacles alternating with eight marginal sense organs. This species reproduces sexually. Four gonads arise as elongated endodermal proliferations, developing"
"jellyfish to defend itself against possible predators. Certain species of ""Cassiopea"" have been observed to enter a sleep state, indicated by a decreased pulsation rate. Cassiopea Cassiopea (upside-down jellyfish) is a genus of true jellyfish and the only members of the family Cassiopeidae. They are found in warmer coastal regions around the world, including shallow mangrove swamps, mudflats, canals, and turtle grass flats in Florida, and the Caribbean and Micronesia. The medusa usually lives upside-down on the bottom, which has earned them the common name. Where found, there may be numerous individuals with varying shades of white, blue, green and"
"differ by a single letter has also led to the misspelling of the species as ""Atropus atropus"" in some publications. The species is most commonly referred to in English as the cleftbelly trevally, with other names including cleftbelly kingfish, Kuweh trevally and thin crevalle. It is also occasionally called the 'blackfin jack', but should not be confused with ""Hemicaranx zelotes"", also known by that name. The cleftbelly trevally has a body shape similar in many ways to a number of the larger jacks, with a strongly compressed body almost ovate in shape. The dorsal profile of the head is straight"
"is a balance organ at each of the eight indentations between the lobes – the rhopalium – which helps the jellyfish orient itself. From the central mouth extend broad frilly oral arms with many stinging cells. Closer to its mouth, its total number of tentacles is around 1200. The long, thin tentacles which emanate from the bell's subumbrella have been characterised as “extremely sticky”; they also have stinging cells. The tentacles of larger specimens may trail as long as or more, with the tentacles of the longest known specimen measured at in length. This unusual length – longer than a"
"Jellynose fish The jellynose fishes or tadpole fishes are the small order Ateleopodiformes. This group of ray-finned fish is monotypic, containing a single family Ateleopodidae. It has about a dozen species in four genera, but these enigmatic fishes are in need of taxonomic revision. The scientific name means """"Ateleopus""-shaped"", from ""Ateleopus"" (the type genus) + the standard fish order suffix ""-formes"". It ultimately derives from Ancient Greek ""atelís"" (ἆτελής, ""imperfect"") + ""pús"" (πούς, ""foot"") + Latin ""forma"" (""external form""), the Greek part in reference to the reduced pectoral and ventral fins of the jellynoses. Jellynoses are deep-water, bottom-dwelling, marine fishes."
"larger species. Coronatae is the only order in this subclass, with around thirty-five species having been described, most of them deepwater jellyfish. The thimble jellyfish (""Linuche unguiculata"") is a tiny species, and one of the few from shallow tropical seas; It is a zooxanthellate species. Coronatids have a characteristic constriction, the coronal groove, part way down the bell. Below this the bell is creased and lobed into four pedalia. Each pedalium bears a small non-retractible tentacle, and the margin of the bell bears either four or eight rhopalia (sensory organs) in the niches between flaps known as lappets. The coronal"
"lion's mane jellyfish. This was later corrected – in 1864, a bootlace worm (""Lineus longissimus"") was found washed up on a Scottish shore that was long. (""That"" claim has its critics: because bootlace worms can easily stretch to several times their natural length, it is possible the worm did not actually grow to be that length.) Lion's mane jellyfish The lion's mane jellyfish, also known as the giant jellyfish or the hair jelly, is the largest known species of jellyfish. Its range is confined to cold, boreal waters of the Arctic, northern Atlantic, and northern Pacific Oceans. It is common"
"Phacellophora camtschatica Phacellophora camtschatica, commonly known as the fried egg jellyfish or egg-yolk jellyfish, is a very large jellyfish in the family Ulmaridae. It has a bell up to 60 cm (2 ft) in diameter and 16 clusters of up to a few dozen tentacles, each up to 6 m (20 ft) long. This cool-water species can be found in many parts of the world's oceans. It feeds mostly on smaller jellyfish and other gelatinous zooplankton, which become ensnared in the tentacles. Because the sting of this jellyfish is so weak, many small crustaceans, including larval crabs (""Cancer gracilis"") and"
"and in the Pacific, leatherback sea turtles, whose diet consists largely of jellyfish, have been observed feeding on their gonads and tentacles, the parts which have the highest nutritional values. Poralia Poralia is a genus of jellyfish in the family Ulmaridae. It is a monotypic genus containing a single species, Poralia rufescens. This jellyfish is pelagic, and is found in deep water in most of the world's oceans. ""Poralia rufescens"" has a bell about in diameter. It has 30 marginal tentacles interspersed with 15 rhopalia (sensory organs). The lappets (flaps) are rectangular in outline and are all the same length,"
"Eupilema inexpectata The root-mouthed jellyfish (""Eupilema inexpectata"") is a species of cnidarian, a jellyfish in the small family Rhizostomatidae. It is the only member of the genus Eupilema. This large jellyfish grows up to more than 1m in diameter. It has a smooth-surfaced bell with no tentacles. Its large manubrium (mouth) has many microscopic holes which extend directly into the gut. This jellyfish is found around the whole South African coast from the surface to at least 35m underwater. This is a large jellyfish which feeds on microscopic prey. It is often seen with small fish, which use its bulk"
"Lion's mane jellyfish The lion's mane jellyfish, also known as the giant jellyfish or the hair jelly, is the largest known species of jellyfish. Its range is confined to cold, boreal waters of the Arctic, northern Atlantic, and northern Pacific Oceans. It is common in the English Channel, Irish Sea, North Sea, and in western Scandinavian waters south to Kattegat and Øresund. It may also drift into the southwestern part of the Baltic Sea (where it cannot breed due to the low salinity). Similar jellyfish – which may be the same species – are known to inhabit seas near Australia"
"jellyfish and has recorded several songs about them. Turritopsis dohrnii Turritopsis dohrnii, the immortal jellyfish, is a species of small, biologically immortal jellyfish found in the Mediterranean Sea and in the waters of Japan. It is one of the few known cases of animals capable of reverting completely to a sexually immature, colonial stage after having reached sexual maturity as a solitary individual. Others include the jellyfish """" and ""Aurelia"" sp.1. Like most other hydrozoans, ""T. dohrnii"" begin their life as tiny, free-swimming larvae known as planula. As a planula settles down, it gives rise to a colony of polyps"