A 13-kilometer (8-mile) diameter crater being infilled by the Medusae Fossae Formation.
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Haeckel was enlisted to visualize the expedition's sea creature findings, such as siphonophores, medusae (jellyfish), and microscopic radiolarians.
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To their amazement, the submersible captured haunting images of the large medusae, some of them dragging their one-foot-long tentacles behind them.
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The Medusae Fossae Formation (MFF) was first observed in the 1960s via the Mariner spacecraft, but NASA scientists could not explain what caused it.
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Juhl now suspects that cold winters are actually really good for jellyfish in the medusae stage; the thick layer of sea ice may acting as a shield, protecting the jellies from turbulent waters.
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The scientists' research, published in Marine Ecology, shows that a species of large jellyfish known as Chrysaora melanaster is capable of surviving the arctic winter in its adult form, a life stage known as medusae.
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Containing everything from delicate comb jellies to the medusae that roam the seas and sting fish with their venomous tentacles, Qingjiang reveals that these animals were well established at the time and actually thriving in some environments.
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" The researchers were able to use data from various Mars orbiter spacecraft in order to measure the Medusae Fossae's density for the first time, calling out its porous nature (it&aposs approximately two-thirds as dense as the rest of the Martian crust) and theorized that it was caused by "explosive volcanic eruptions.
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Prior to these observations, which were made from 2011 to 2014, scientists thought that the under sea conditions were too harsh for adult jellies during the winter months, and that this species could only survive under the arctic ice during its stage as a polyp—a formless blob that releases tiny baby medusae in the spring.
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The medusae of Linantha lunulata can be distinguished from other crown jellyfish medusae by having four inter-radial gonads shaped like horseshoes, and no subumbrella.
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His enemy is the Purple pretender Eric Ulnar, who sought the Medusae out in the first place, seeking to become the next Emperor of The Sun. The Medusae conquered the Moon, set up their bases there, and went on to attempt conquest of the Solar System. The Medusae had for eons used a reddish, artificial greenhouse gas to keep their dying world from freezing. The Medusae learned from the first human expedition to their world that the gas rots human flesh, and the Medusae use it as a potent chemical weapon, attempting ecological destruction by means of projectiles fired from the Moon.
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The B. muscus hydroid buds and forms medusae by asexual reproduction. When these mature, sexual reproduction occurs, the fertilised eggs settle out and new hydroids are formed. The hydroid grows rapidly and may starts to produce medusae when as little as seven weeks old. The medusae grow on the side branches and become free swimming when they are released.
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Such aggregation can affect the feeding and predation of medusae.
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They spoke of a gigantic planet, populated by ferocious animals and the single city left of the evil "Medusae". The Medusae bear a vague resemblance to jellyfish, but are actually elephant-sized, four-eyed, flying beings with hundreds of tentacles. The Medusae cannot speak and communicate with one another via a microwave code. The Falstaff character is named Giles Habibula.
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Ephyrae develop into juvenile medusae after a further fifteen days or so.
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The change from polyp to tiny medusae, initially measuring only , typically happens when the water surpasses . Because of this, the medusae follow an annual pattern and first appear in the spring or later depending on temperature, sometimes causing sudden blooms where many show up at once. The medusae stage generally lasts no more than three months, but the species can live for years in the polyp stage. During the day the medusae will attach themselves with the adhesive patches on their tentacles to various surfaces, especially seagrass, earning the species its common name clinging jellyfish.
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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 release 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.
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The Medusa orchid was first formally described in 1861 by John Lindley who gave it the name Cirrhopetalum medusae and published the description in Edwards's Botanical Register. In 1861, Heinrich Gustav Reichenbach changed the name to Bulbophyllum medusae. Bulbophyllum medusae grows on the trunk and main branches of trees in forest at altitudes up to in Thailand, Malaysia, Borneo, the Lesser Sunda Islands and Sumatra.
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The Medusae cannot speak, and communicate with one another via a microwave code.
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Medusae of T. dohrnii are able to survive between 14 °C and 25 °C.
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Calosima medusae is a moth in the family Blastobasidae which is endemic to Costa Rica.
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In January 2000, the golden jellyfish medusae were observed in Jellyfish Lake for the first time since April 1999. By May 2012, the medusae population had returned to pre-decline levels. Dawson et al. also surveyed the golden jellyfish populations in three other Palauan marine lakes.
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Hydrozoans have two distinct stages in their life, a polyp stage and a medusa stage. The polyp stage is benthic, with the cells forming colonies, while the medusa stage is a singular, planktonic organism. Generally in hydrozoa the medusa develops from the asexual budding of the polyp and the polyp results from sexual reproduction of medusae. In T. nutricula, planktonic medusa have the capability to bud polyps or medusae which also have the ability to spawn new medusae.
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Curiously, although a healthy captive Velella will release many medusae under the microscope, and are expected to do the same in the sea, the medusae of Velella are rarely captured in the plankton and very little is known about their natural history. The medusae develop to sexual maturity within about three weeks in the laboratory and their free-spawned eggs and sperm develop into a planktonic larva called a conaria, which develops into a new floating Velella hydroid colony.
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Chisocheton medusae is endemic to Borneo. The habitat is lowland rain forests from sea-level to altitude.
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Medusae also have eight tentacles, alternating with eight rhopalia, and twice as many lappets occur as tentacles.
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Jellyfish exhibits both asexual and sexual reproduction by budding during hydroid stage and releasing gametes in medusae stages.
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The main stalky body of the colony is composed of a coenosarc, which is covered by a protective perisarc. The next generation of the life cycle begins when the medusae are released from the gonozooids, producing free swimming only male medusae velum with gonads, a mouth, and tentacles. The physical appearance of the male and female medusae velum, including their gonads, are indistinguishable, and the sex can only be determined by observing the inside of the gonads, which will either contain sperm or eggs. The medusae reproduce sexually, releasing sperm and eggs that fertilize to form a zygote, which later morphs into a blastula, then a ciliated swimming larva called a planula.
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Diplulmaris antarctica feeds on copepods, euphausiid larvate, medusae, ctenophore, fish larvae, and molluscan pteropods such as Clione antarctica and Limacina antarctica.Larson R. J. & Harbison G. R. (1990). "Medusae from Mcmurdo Sound, Ross Sea including the descriptions of two new species, Leuckartiara brownei and Benthocodon hyalinus". Polar Biology 11(1): 19-25. .
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When this occurs, there can be an externally visible dilation of the paraumbilical (and perhaps even the thoracoepigastric veins) which leads to the appearance of "Caput Medusae". Caput Medusae is a clinical sign that is recognized by the physician by the characteristic appearance of distended veins emanating from the umbilicus of the patient. The shape of these veins and their arrangement around the umbilicus is said to resemble the snake-like hair of the mythological Greek Monster, Medusa. "Caput Medusae" [Latin] means "Head of Medusa".
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The story takes place in an era in which humans have colonized the Solar System but dare not go farther, as the first extra-solar expedition to Barnard's Star failed and the survivors came back as babbling, grotesque, diseased madmen. These survivors spoke of a gigantic planet, populated by ferocious animals, and of the single city of the evil "Medusae". The Medusae are elephant-sized, four-eyed, flying 'jellyfish' with hundreds of tentacles. The Medusae cannot hear or speak, but communicate with one another via radio waves.
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Like a number of carangids, juvenile yellowtail scad are known to congregate around floating objects, including jellyfish medusae, as well as manmade structures. In Kaneohe Bay, jellyfish medusae disappeared from the bay, causing the fish to switch from natural objects to manmade ones, causing concern for recruitment of the species in the future.
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These multiply asexually or can bud off medusae. In some species, medusae are only produced when the water temperature exceeds a certain level. Most species are marine, but several can also be found in brackish water and a few, notably Craspedacusta (such as C. sowerbii) and Limnocnida, are found in fresh water.Didžiulis, Viktoras: Craspedacusta sowerbyi.
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The colony of O. dichotoma forms slender alternative branching stems with hydrocauli up to 350 mm tall with the hydranths located on thin stalks. The medusae of O. dichotoma swim freely in water and are disk shaped with 16 or more tentacles. The medusae tentacles are not highly specialized but contain nematocysts grouped in rings.
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They have also been found on the oral arms of the jellyfish where they can eat prey caught by the medusae.
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Clinical signs of portal hypertension include those of chronic liver disease: ascites, esophageal varices, spider nevi, caput medusae, and palmar erythema.
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Mature medusae are about 10 mm. in diameter and are found in swarms off the coast between Cape Hatteras, North Carolina, and Cape Canaveral, Florida. They are practically confined to pure open water and do not frequent the harbors. The mature medusae bear many ball-like clusters of developing planulae gathered into the peripheral canals of the gastric space.
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The gonophores in the family Corynidae are borne on hydranths and either liberated as free medusae or retained as medusoids or sessile sporosacs. The gonophores in the family Hydrocorynidae are borne in clusters on proximal part of hydranth body or develop from hydrorhiza (i.e. the stalk of a colony). The gonophores develop into free medusae or sessile sporosacs.
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Budding only happened when the hydroids were kept at water temperatures of ; not or . In contrast, the two warmer temperatures appeared to produce more medusae. This indicates that hydroid growth and reproduction (budding) occur in or less, while warmer temperatures initiate the change into medusae. This matches the annual sea temperature variations observed in its native range.
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Hydrozoans exhibit the greatest variety of life cycles among medusozoans, with either the polyp or the medusa stage being missing in some groups. In general, medusae are budded laterally from polyps, become mature and spawn, releasing gametes into the water. The planulae may settle to become polyps or continue living in the water column as medusae.
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Tillandsia caput-medusae is a species of flowering plant in the bromeliad family, Bromeliaceae, subfamily Tillandsioideae. Common names include octopus plant and medusa's head. An epiphyte native to Central America and Mexico, T. caput-medusae is a commonly cultivated bromeliad species. The thick, channeled, tapering and twisting leaves are up to long and are covered in fine gray hairs.
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Evidence for equatorial hydration is both morphological and compositional and is seen at both the Medusae Fossae formation and the Tharsis Montes.
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They remain attached to the hydroids or break off to be passively drifted away; in a few, the gonophores are naked. The gonophores in the family Sphaerocorynidae are borne singly or on short, branching blastostyles (i.e. the living axial portion of a modified gonangium, from which numerous medusae are budded) between or below tentacles. They develop into free medusae or eumedusoids.
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John Ulnar and his companions rescue Aladoree, but the invasion of the Solar System has already begun. The Medusae conquer the Moon, set up bases there, and bombard Earth with gas projectiles. John, Aladoree, and their companions land on a ravaged Earth. Fighting off cannibals maddened by the gas, they build AKKA and destroy the Medusae fleets (and Earth's Moon as well).
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The medusae are bell-shaped with a circular mouth and branched oral tentacles inserted above the rim of the mouth, ending in clusters of nematocysts.
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Some hydroids may consist of colonies of zooids that serve different purposes, such as defense, reproduction and catching prey. The mesoglea of polyps is usually thin and often soft, but that of medusae is usually thick and springy, so that it returns to its original shape after muscles around the edge have contracted to squeeze water out, enabling medusae to swim by a sort of jet propulsion.
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Reproduction in fire corals is more complex than in other reef-building corals. The polyps reproduce asexually, producing jellyfish-like medusae, which are released into the water from special cup-like structures known as ampullae. The medusae contain the reproductive organs that release eggs and sperm into the water. Fertilised eggs develop into free-swimming larvae that will eventually settle on the substrate and form new colonies.
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Under certain conditions reproductive structures called gonothecae form at junctions of older branches and gonophores develop inside these. Male or female medusae develop inside the gonophores, become detached and drift planktonically with the currents for one to four weeks. When the medusae are mature, gametes are released into the sea. Fertilisation is external and the sperm seems to be chemically attracted to the eggs.
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When she is kidnapped by a huge alien spaceship, John and the three other survivors of the guard force follow her kidnappers to a planet of Barnard's Star. They crash-land and must battle their way across a savage continent to the sole remaining citadel of the Medusae. John Ulnar's uncle and his nephew have allied with the Medusae as a means to regain their empire, and have kidnapped Aladoree to ensure that AKKA is not used against them. The Medusae, however, turn on the Purples, seeking to destroy all humans and move to the Solar System, as their own world, far older than Earth, is spiraling into Barnard's Star.
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In this story, these warriors of the 30th century battle the Medusae, the alien race from the lone planet of Barnard's Star. The Legion itself is the military and police force of the Solar System after the overthrow of an empire called the Purple Hall that once ruled all humans. In the novel, renegade Purple pretenders ally themselves with the Medusae as a means to regain their empire. But the Medusae, who are totally unlike humans in all ways, turn on the Purples, seeking to destroy all humans and move to the Solar System, as their own world, far older than Earth, is finally spiraling back into Barnard's Star.
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Chisocheton medusae is a tree in the family Meliaceae. The specific epithet ' refers to the mythological Medusa and alludes to the shape of the flower petals.
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Bulbine caput-medusae is a species of plant in the Asphodelaceae family. It is endemic to Namibia. Its natural habitats are dry savanna and hot deserts.
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The B. britannica hydroid buds and forms medusae by asexual reproduction. When these mature, sexual reproduction occurs, the fertilised eggs settle out and new hydroids are formed.
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Having settled, the larvae undergo metamorphosis into the hydroid stage of the lifecycle, forming tiny sessile polyps called scyphistomae. Under favorable conditions these bud and form further scyphistomae. In due course, when they have acquired zooxanthellae and the temperature exceeds , these strobilate (split) and new medusae are formed. In Florida, the medusae are found all the year round but the scyphistomae are only present in late summer and fall.
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When conditions are not favorable for the short lived medusa stage or for syphistomae strobilation, the medusae disappear in Clear Lake. The medusa population is reestablished by syphistomae strobilation when conditions are favorable for strobilation and medusae again. A significant reduction in the Jellyfish Lake medusa population had also been noted in 1987. This was previously attributed to turbulence generated by scuba diving that caused disturbance of the toxic layer.
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There is considerable divergence from the basic life cycle pattern among medusozoans. Scyphozoa is the group commonly known as "true jellyfish" and occur in tropical, temperate and polar seas worldwide. Scyphozoans generally have planula larvae that develop into sessile polyps. These reproduce asexually, producing similar polyps by budding, and then either transform into medusae, or repeatedly bud medusae from their upper surface in a process known as strobilation.
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Colin SP, Kremer P. 2002. Population maintenance of the scyphozoanCyanea sp. Settled planulae and the distribution of medusae in the Niantic River, Connecticut, USA. Estuaries 25:70–75.
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It is the state grass of Montana, Oregon, and Washington. The grass is outcompeted by noxious weeds such as diffuse knapweed (Centaurea diffusa) and medusahead (Taeniatherum caput-medusae).
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The medusa stage of Obelia species are common in coastal and offshore plankton around the world.Cornelius, P.F.S., 1995b. North-West European thecate hydroids and their Medusae. Part 2.
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Salonen; Högmander; Langenberg; Mölsä; Sarvala; Tarvainen; and Tiirola (2012). Limnocnida tanganyicae medusae (Cnidaria: Hydrozoa): a semiautonomous microcosm in the food web of Lake Tanganyika. Hydrobiologia 690(1): 97–112.
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The planula of Clytia gregaria settle on a variety of substrates, on both horizontal and vertical surfaces. The planula then flattens into a pedal disk with 4-6 lobes. A stolon is visible after approximately a week, which then branches and forms a colony of hydroids. Medusae are released approximately 35–45 days after fertilization, from spring to early fall. Newly hatched medusae have 4 tentacles, with an additional 4 immature tentacular buds.
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Cubozoa is a group commonly known as box jellyfish, that occur in tropical and warm temperate seas. They have cube-shaped, transparent medusae and are heavily-armed with venomous nematocysts. Cubozoans have planula larvae, which settle and develop into sessile polyps, which subsequently metamorphose into sexual medusae, the oral end of each polyp changing into a medusa which separates and swims away. Staurozoa is a small group commonly known as stalked jellyfish.
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The Nature Conservancy. Introduced species of plants in the area are also a threat, including red brome (Bromus madritensis ssp. rubens), yellow starthistle (Centaurea solstitialis), and medusahead (Taeniatherum caput- medusae).
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However, many live along the coast in temperate climates (10) and around coastal environments where it is safer for the polyps to develop (1). As the temperature of the water increases, whether with global warming or seasonal, the number of medusae increases as well as the ratio of polyps to medusae (8). Without the influence of wind and water currents, Aurelia live alone, however, they are thought to be brought together into aggregations as a result of wind and water currents (10). With all of the variability from their environments, the medusae of Aurelia are able to “de- grow” which allows them to cheat death in a way until proper conditions are met in order to survive by becoming a smaller medusa (5).
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The bell of the jellyfish (medusae) is only in diameter, exceptionally up to , and when fully extended a tentacle can be twice the length of the bell diameter. The medusae reproduce sexually and the tens of thousands of eggs and sperm are released into the sea. They become planula larvae that eventually attach themselves to the seabed on algae, rocks or shells as tiny polyps that measure up to . The polyps can split into several by budding.
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The fertilized egg produces a planular larva which, in most species, quickly attaches itself to the sea bottom. The larva develops into the hydroid stage of the lifecycle, a tiny sessile polyp called a scyphistoma. The scyphistoma reproduces asexually, producing similar polyps by budding, and then either transforming into a medusa, or budding several medusae off from its upper surface via a process called strobilation. The medusae are initially microscopic and may take years to reach sexual maturity.
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Medusahead was first described Elymus caput-medusae by Carl Linnaeus. Nevski recommended in 1934 that the Russian types of medusahead should be classified in a separate genus, Taeniatherum. In the 1960s, it was suggested by Jack Major of the University of California that there are three geographic and morphologically distinct taxa: T. caput-medusae, T. asperum, and T. crinitum. After traveling in Russia, Major thought the proper classification for the plant introduced to North America was Taeniatherum asperum.
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Schuchert (2005) Some enigmatic actively swimming medusae have been tentatively placed in this family as a kind of "wastebin taxon". Should their associated hydroids turn out to belong elsewhere, they are to be moved to that family and genus. The relationships of this fairly small but distinctive radiation to other families of Leptothecata are not well understood at present. However, the family Lovenellidae, often turn out to contain the hydroid stage of medusae formerly placed in the family Haleciidae.
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These polyps develop over a few days into tiny 1 mm medusae, which are liberated and swim free from the parent hydroid colony. Images of both the medusa and polyp of the closely related species Turritopsis rubra from New Zealand can be found online. Until a recent genetic study, it was thought that Turritopsis rubra and Turritopsis nutricula were the same. It is not known whether or not T. rubra medusae can also transform back into polyps.
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This can also occur in the esophagus, causing esophageal varices, and at the level of the umbilicus, causing caput medusae. Between 44% and 78% of patients with portal hypertension get anorectal varices.
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Astrophytum caput-medusae (synonym Digitostigma caput-medusae) is a species of cactus native to Mexico, specifically the state of Nuevo León; the plant is reported to grow wild only at a single location. This species differs from the conventional star-shaped phenotype associated with other Astrophytum members. The plant is characterized by a cylindrical, reduced stem with triangular or cylindrical tubercles producing yellow flowers with orange perianth sections. Propagation by seed, tissue culture or via grafting have all been reported.
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The gonophores in the family Candelabridae are fixed sporosacs. They develop on the aboral part of the hydranth below the tentacle-covered region, either directly on the hydranth or on spindle-shaped blastostyles. The gonophores in the family Tubulariidae develop above the aboral tentacles and develop into free medusae or fixed sporosacs The gonophores in the family Corymorphidae are borne above aboral tentacles, either directly issuing from hydranth wall or on blastostyles. The gonophores develop into free medusae or fixed sporosacs.
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Coronamedusae is a subclass of jellyfish in the class Scyphozoa. It is the sister taxon of Discomedusae and contains about 50 named species, all included in the order Coronatae. Jellyfish in this subclass are either small medusae living in shallow marine environments, or large medusae living in the deep sea. The mouthparts of the members of this subclass are characterised by simple lips on a short manubrium as well as by robust marginal tentacles that arc away from the mouth.
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Huxley's paper "On the anatomy and the affinities of the family of Medusae" was published in 1849 by the Royal Society in its Philosophical Transactions. Huxley united the Hydroid and Sertularian polyps with the Medusae to form a class to which he subsequently gave the name of Hydrozoa. The connection he made was that all the members of the class consisted of two cell layers, enclosing a central cavity or stomach. This is characteristic of the phylum now called the Cnidaria.
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Obelia dichotoma house the reproductive polyps in the angles of the branches. The polyps develop and bud off to form medusae about 0.05 mm in diameter at release that grow to about 5 mm at maturity. The medusae are either male or female with nematocysts on tentacles and produce either sperm or eggs. The fertilized egg develops into a planula larvae that settle out of the water column during the winter, spring, and early summer and grow colonies for 2-3 months.
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Six of the pairs of mesenteries dividing the internal body cavity are perfect while the other four are imperfect, with powerful retractor muscles. There is no sphincter muscle. The larvae are parasitic on medusae.
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The cnidome may have stenoteles. Trachymedusae reproduce sexually during the medusae stage lacking a polyp stage. Primarily found in the deep ocean, where they are recorded at depths of seventy to two thousand metres.
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Texas Cacti. Texas A&M; University Press, College Station. xv, 291. Some of these species have very limited distributions and are endemic to the region such as Astrophytum caput- medusae from Nuevo Leon, Mexico.
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NOBANIS - Invasive Alien Species Fact Sheet. Retrieved 22 September 2014.Salonen; Högmander; Langenberg; Mölsä; Sarvala; Tarvainen; and Tiirola (2012). Limnocnida tanganyicae medusae (Cnidaria: Hydrozoa): a semiautonomous microcosm in the food web of Lake Tanganyika.
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Aequorea victoria have a dimorphic life history, alternating between asexual benthic polyps and sexual planktonic medusae in a seasonal pattern.Brusca, Richard C., and Brusca, Gary J. Invertebrates. 2nd. Sunderland, MA: Sinauer Associates, Inc., 2003.
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This nudibranch is transparent with guts visible through the laterally flattened body. It has a tail and two long smooth rhinophores. It feeds on jellyfish and plankton as an adult. The juveniles parasitize Zanclea medusae.
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The medusae bud and loosen from the mature polyps between January and March around the British Isles and southern North Sea. This occurs in a similar way to the life cycle of the moon jellyfish.
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Other studies refute the idea that global jellyfish populations are increasing at all; they state that these variations are simply part of the larger-scale climatic and ecosystem processes. The lack of data has been interpreted as a lack of blooms. An additional difficulty with studying jellyfish bloom dynamics is understanding how populations change in both the polyp and medusae life stages of a jellyfish. Medusae are much easier for researchers to track and observe due to their size and presence in the water.
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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 was an El Niño weather event that raised the water temperature, with the result that the symbiotic algae (Zooxanthellae) that live within the golden jellyfish medusae and the syphistomae (scyphozoan polyps) could not survive.
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Oral end of actinodiscus polyp, with close-up of the mouth Most adult cnidarians appear as either free-swimming medusae or sessile polyps, and many hydrozoans species are known to alternate between the two forms. Both are radially symmetrical, like a wheel and a tube respectively. Since these animals have no heads, their ends are described as "oral" (nearest the mouth) and "aboral" (furthest from the mouth). Most have fringes of tentacles equipped with cnidocytes around their edges, and medusae generally have an inner ring of tentacles around the mouth.
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Caput medusae is the appearance of distended and engorged superficial epigastric veins, which are seen radiating from the umbilicus across the abdomen. The name caput medusae (Latin for "head of Medusa") originates from the apparent similarity to Medusa's head, which had venomous snakes in place of hair. It is also a sign of portal hypertension. It is caused by dilation of the paraumbilical veins, which carry oxygenated blood from mother to fetus in utero and normally close within one week of birth, becoming re-canalised due to portal hypertension caused by liver failure.
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They developing into free medusae or fixed sporosacs. The gonophores in the family Solanderidae, where known, arise directly from coenosarc (i.e. the hollow living tubes of the upright branching individuals of a colony). They are cryptomedusoid or eumedusoid.
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The common surface features of Mars include dark slope streaks, dust devil tracks, sand dunes, Medusae Fossae Formation, fretted terrain, layers, gullies, glaciers, scalloped topography, chaos terrain, possible ancient rivers, pedestal craters, brain terrain, and ring mold craters.
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Bougainvillia aberrans n. sp. has holotype and paratype. Also, medusae of B. aberrans appear sexually mature and relatively short-lived for release from the hydroid. It is different from the reduced Medusa buds with its blunt marginal tentacles.
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Melampsora medusae is a fungal pathogen, causing a disease of woody plants. The infected trees' leaves turn yellowish-orange. The disease affects mostly conifers, e.g. the Douglas-fir, western larch, tamarack, ponderosa, and lodgepole pine trees, but also some broadleaves, e.g.
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The polyp grows singly from a stolon or has a few branches. It has long pedicels and medusa buds develop in clusters on branched stalks. The young medusae have very narrow subumbrellas. The medusa has thick jelly and no peduncle.
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The hydranths have a circular mouth surrounded by a single whorl of adhesive tentacles which each bear a little knob at the tip; in some Cladonematidae an aboral whorl of thread-like unknobbed tentacles is also present. They have a preoral chamber formed by epidermal gland cells. The medusae bud off at the base of the hydrants, though where aboral tentacle are present these are located between the stolons and the budding sites. Cladonematidae medusae have a various extend of nematocysts around their umbrellar margin, varying between a continuous dense ring to none at all among the species.
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The Medusae learned from the first human expedition to their world that the gas rots human flesh, and the Medusae use it as a potent chemical weapon, attempting ecological destruction by means of projectiles fired from the Moon. Their vast spaceships also have very effective plasma weapons, very similar to those the Romulans had in a Star Trek episode called Balance of Terror. This first Legion tale featured a secret weapon called AKKA. Using a space/time distortion, it could erase from the Universe any matter, of any size, anywhere, even a star or a planet.
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Each by-the- wind sailor is a colony of all-male or all-female polyps. The colony has several different kinds of polyps, some of which are both feeding and reproductive, called gonozooids, and others protective, called dactylozooids. The gonozooids each produce numerous tiny jellyfish by an asexual budding process, so that each Velella colony produces thousands of tiny jellyfish (medusae), each about 1 mm high and wide, over several weeks. The tiny medusae are each provided with many zooxanthellae, single-celled endosymbiotic organisms typically also found in corals and some sea anemones, that can utilize sunlight to provide energy to the jellyfish.
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Portacaval anastomosis, by contrast, is an anastomosis between a vein of the portal circulation and a vein of the systemic circulation, which allows blood to bypass the liver in patients with portal hypertension, often resulting in hemorrhoids, esophageal varices, or caput medusae.
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This area is considered to be among the youngest parts of Mars because it has a very low density of craters. The Amazonia period is named after this area. This quadrangle contains special, unusual features called the Medusae Fossae Formation and Sulci.
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A few species are parasitic on other marine organisms. One of these is Peachia quinquecapitata, the larvae of which develop inside the medusae of jellyfish, feeding on their gonads and other tissues, before being liberated into the sea as free-living, juvenile anemones.
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The bigeye squaretail, Tetragonurus atlanticus, is a fish native to the Atlantic, Indian and Pacific Oceans. They feed on soft-bodied medusae and salps and will also eat plankton. Their average length is 50 cm, and their habitat is pelagic. They are toxic to humans.
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In portal hypertension, the vessels surrounding the liver are subjected to abnormally high blood pressure--so high, in fact, that the force of the blood pressing against the round ligament is sufficient to recanalize the structure. This leads to a condition called Caput medusae.
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Hydroids in this family can be solitary or colonial. When colonial, the hydranths or hydroid polyps are either linked by stolons or are branched. The hydranths have one or more whorls of fine tentacles. The gonophores are free-living medusae or are fixed sporosacs.
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Reproduction in Vallentinia gabriellae has two phases. These are the medusa or jellyfish which reproduces sexually and a polyp that reproduces by budding. The male and female medusae liberate gametes into the water column. After fertilisation, the eggs develop into planula larvae which are planktonic.
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Alatina alata is mostly observed in shallow near shore waters in tropical and subtropical climate, but also occurs offshore in deeper ocean waters. Live medusae collected had hyperiidae amphipods in their subumbrella and some had small carid shrimps and euphausiids in the gut or subumbrella.
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Mémoires du Muséum national d'Histoire naturelle, 194. Muséum national d'Histoire naturelle: Paris, France. . 591pp. + 1 cd-rom In hydrozoan species with both polyp and medusa generations, the medusa stage is the sexually reproductive phase. Medusae of these species of Hydrozoa are known as "hydromedusae".
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The northern part of Elysium Planitia, a broad plain, is in this quadrangle. The Elysium quadrangle includes a part of Lucus Planum. A small part of the Medusae Fossae Formation lies in this quadrangle. The largest craters in this quadrangle are Eddie, Lockyer, and Tombaugh.
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Little is known of the life histories of many jellyfish as the places on the seabed where the benthic forms of those species live have not been found. However, an asexually reproducing strobila form can sometimes live for several years, producing new medusae (ephyra larvae) each year. An unusual species, Turritopsis dohrnii, formerly classified as Turritopsis nutricula, might be effectively immortal because of its ability under certain circumstances to transform from medusa back to the polyp stage, thereby escaping the death that typically awaits medusae post-reproduction if they have not otherwise been eaten by some other organism. So far this reversal has been observed only in the laboratory.
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The Legion itself is the military and police force of the Solar System after the overthrow of an empire called the Purple Hall that once ruled all humans. In this novel, renegade Purple pretenders ally themselves with the Medusae as a means to regain their empire. But the Medusae, who are totally unlike humans in all ways, turn on the Purples, seeking to destroy all humans and move to the Solar System, as their own world, far older than Earth, is finally spiraling back into Barnard's Star. One of the Purples, John Ulnar, supports the Legion from the start, and he is the fourth great warrior.
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Hydroid colonies are usually dioecious, which means they have separate sexes—all the polyps in each colony are either male or female, but not usually both sexes in the same colony. In some species, the reproductive polyps, known as gonozooids (or "gonotheca" in thecate hydrozoans) bud off asexually produced medusae. These tiny, new medusae (which are either male or female) mature and spawn, releasing gametes freely into the sea in most cases. Zygotes become free-swimming planula larvae or actinula larvae that either settle on a suitable substrate (in the case of planulae), or swim and develop into another medusa or polyp directly (actinulae).
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In 1848, he published his monograph on jellyfish, the British Naked-eyed Medusae (Ray Society). In 1852, Forbes published the fourth and concluding volume of Forbes and S. Hanley's History of British Mollusca He also published his Monograph of the Echinodermata of the British Tertiaries (Palaeontographical Soc.).
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All cnidarians can regenerate, allowing them to recover from injury and to reproduce asexually. Medusae have limited ability to regenerate, but polyps can do so from small pieces or even collections of separated cells. This enables corals to recover even after apparently being destroyed by predators.
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Bright violet flowers are about long with the stamens exerted. Tillandsia caput-medusae does not have any free water retention in its overlapping leaves because its abaxial and adaxial leaf bases provides trichomes which coats the leaves. The significance of trichome is to enhance leaf permeability.
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Removal of competitive top- predator fish due to overfishing has resulted in reduced competition for jellyfish food resources. During a jellyfish bloom, ichthyoplankton, crustacean zooplankton (e.g. copepods and krill), and smaller medusae can be more heavily consumed. Some studies have shown jellyfish can outcompete other predators in a bloom.
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Box jellyfish (class Cubozoa) are cnidarian invertebrates distinguished by their cube-shaped medusae. Some species of box jellyfish produce extremely potent venom: Chironex fleckeri, Carukia barnesi and Malo kingi. Stings from these and a few other species in the class are extremely painful and can be fatal to humans.
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Atolla wyvillei, also known as the Atolla jellyfish or Coronate medusa, is a species of deep-sea crown jellyfish (Scyphozoa: Coronatae). It lives in oceans around the world.Russell, F.S., (1970) The medusae of the British Isles. II. Pelagic Scyphozoa with a supplement to the first volume on Hydromedusae.
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In the largest species, the medusae can grow to . Centripetal canals may be present or absent and the radial canals are unbranched. The gonads are beside the radial canals, except in Limnocnida, where they are on the manubrium. The fertilised eggs develop into planula larvae which become polyps.
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As ephraye mature, the tentacles elongate and become filiform. Medusae reach larger bell diameters, additional tentacles form and oral arms elongate. Gastric system develops in a centrifugal direction. After roughly 9 months (under laboratory conditions), sexual maturity is achieved and reproduction can be achieved within the water column.
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The nectophores pump the water back in order to move forward. Calycophorans differ from cystonects and physonects in that they have two nectophores and no pneumatophore. ;Zooids :Siphonophores can have zooids that are either polyps or medusae. However, zooids are unique and can develop to have different functions.
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Cannonballs eat mainly zooplankton such as veligers, and also all forms of red drum larvae. They have a symbiotic relationship with the portly spider crab, which also eats the small zooplankton. The crab feeds on the prey captured by the cannonball and also on the medusae of the jellyfish.
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The presence of some dust undoubtedly emphasised the phenomenon.Mars Express keeps an eye on curious cloud ESA, October 2018 A study using a global climate model found that the Medusae Fossae Formation could have been formed from ash from the volcanoes Apollinaris Mons, Arsia Mons, and possibly Pavonis Mons.
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Medusae Sulci based on day THEMIS day-time image on Mars Sulcus (plural: sulci ) is, in astrogeology, an area of complex parallel or subparallel ridges and furrows on a planet or moon. For example, Uruk Sulcus is a bright region of grooved terrain adjacent to Galileo Regio on Jupiter's moon Ganymede.
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Food travels through the muscular manubrium while the radial canals help disperse the food. There is a middle layer of mesoglea, gastrodervascular cavity with gastrodermis, and epidermis. There is a nerve net that is responsible for contractions in swimming muscles and feeding responses. Adult medusae can have diameters up to .
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They feed on detritus, including the remains of gelatinous zooplankton (such as salps, larvaceans, and medusae jellies) and complete copepods, ostracods, amphipods, and isopods. Vampire squids have been found among the stomach contents of large, deepwater fish, including giant grenadiers, and deep-diving mammals, such as whales and sea lions.
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A tube-like structure hangs down from the centre of the umbrella, and includes the mouth at its tip. Most hydrozoan medusae have just four tentacles, although a number of exceptions exist. Stinging cells are found on the tentacles and around the mouth. The mouth leads into a central stomach cavity.
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A study using a global climate model found that the Medusae Fossae Formation could have been formed from ash from Apollinaris Mons, Arsia Mons, and possibly Pavonis Mons.Kerber L., et al. 2012. The disporsal of pyroclasts from ancient explosive volcanoes on Mars: Implications for the friable layered deposits. Icarus. 219:358-381.
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A small part of the Medusae Fossae Formation lies in this quadrangle. The name refers to the name of a floating western island of Aiolos, the ruler of the winds. In Homer's account, Odysseus received the west wind Zephyr here and kept it in bags, but the wind got out.Blunck, J. 1982.
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Most authors in the past 40 years have accepted interpretation of these animals as unusual floating colonial athecate hydroids, which produce medusae clearly belonging in the Anthomedusae. Although the exact position of the family Porpitidae within the Athecatae/Anthomedusae is not yet clear, the order Chondrophora is no longer used by hydrozoan systematists.
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The "smell" of fluids from wounded prey makes the tentacles fold inwards and wipe the prey off into the mouth. In medusae the tentacles round the edge of the bell are often short and most of the prey capture is done by "oral arms", which are extensions of the edge of the mouth and are often frilled and sometimes branched to increase their surface area. Medusae often trap prey or suspended food particles by swimming upwards, spreading their tentacles and oral arms and then sinking. In species for which suspended food particles are important, the tentacles and oral arms often have rows of cilia whose beating creates currents that flow towards the mouth, and some produce nets of mucus to trap particles.
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Little is known about the details of its life cycle and no Olindias hydroids have been reported from the wild. Flower hat jellies have bred in a display at the Monterey Bay Aquarium. The hydroids attached themselves to various surfaces and formed small clusters. Eventually the medusae were released at a diameter of about .
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The initial diameter of medusae is up to 1.4 mm, increasing to 2.5 – 3 mm within two days. Sexual maturity can be reached in 4 weeks, or sooner with optimal conditions. (Note that this data is based on laboratory conditions.) Adults are carnivorous, feeding upon soft-bodied prey such as invertebrate eggs and appendicularians.
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The ephyrae, usually only a millimeter or two across initially, swim away from the polyp and grow. Limnomedusae polyps can asexually produce a creeping frustule larval form, which crawls away before developing into another polyp. A few species can produce new medusae by budding directly from the medusan stage. Some hydromedusae reproduce by fission.
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Atolla is a genus of crown jellyfish in the order Coronatae. The genus Atolla was originally proposed by Haeckel in 1880 and elevated to the monotypic family level, as Atollidae by Henry Bigelow in 1913. The six known species inhabit the mesopelagic zone. The medusae possess multiple lobes called lappets at the bell margin.
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Herring, P.J. & E.A. Widder, (2004) Bioluminescence of deep-sea coronate medusae (Cnidaria: Scyphozoa). Marine Biology, 146: pp. 39-51 When attacked, it will launch a series of flashes and, whose function is to draw predators who will be more interested in the attacker than itself. This has earned the animal the nickname "alarm jellyfish".
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For humans, its sting is often irritating, but rarely dangerous. Chrysaora fuscescens has proven to be very popular for display at public aquariums due to their bright colors and relatively easy maintenance. It is possible to establish polyps and culture Chrysaora in captivity. When provided appropriate aquarium conditions, the medusae do well under captive conditions.
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Regardless, most individual medusae are likely to fall victim to the general hazards of life as mesoplankton, including being eaten by predators or succumbing to disease. The species' cell development method of transdifferentiation has inspired scientists to find a way to make stem cells using this process for renewing damaged or dead tissue in humans.
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However, the ecology of the polyp life stage is not well understood in most jellyfish species. Many polyps are difficult to sample due to their fragility. There have been calls for future research to focus on the ecology of both the medusae and the polyp life stages to better understand bloom dynamics throughout the organisms' entire lifespans.
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C. sowerbii begins life as a tiny polyp, which lives in colonies attached to underwater vegetation, rocks, or tree stumps, feeding and asexually reproducing during spring and summer. Some of these offspring are the sexually reproducing medusae. Fertilized eggs develop into small ciliated larvae called planula. The planula then settle to the bottom, and develop into polyps.
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The gonophores in the superfamily Plumularioidea are usually fixed sporosacs (i.e. gonophores held in place and not released into the water during larval development), more rarely they are rather reduced medusoids. The gonophores in the family Lovenellidae are pedunculate free-roaming medusae. The gonophores in the family Haleciidae are typically sporosacs, growing singly or bunched into a glomulus.
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Portacaval anastomosis, by contrast, is a veno-venous anastomosis between a vein of the portal circulation and a vein of the systemic circulation, which allows blood to bypass the liver in patients with portal hypertension, often resulting in hemorrhoids, esophageal varices, or caput medusae. Circulatory anastomoses between monochorionic twins may result in twin-to-twin transfusion syndrome.
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All known cnidaria can reproduce asexually by various means, in addition to regenerating after being fragmented. Hydrozoan polyps only bud, while the medusae of some hydrozoans can divide down the middle. Scyphozoan polyps can both bud and split down the middle. In addition to both of these methods, Anthozoa can split horizontally just above the base.
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It is therefore not surprising that splenomegaly is associated with any disease process that involves abnormal red blood cells being destroyed in the spleen. Other common causes include congestion due to portal hypertension and infiltration by leukemias and lymphomas. Thus, the finding of an enlarged spleen, along with caput medusae, is an important sign of portal hypertension.
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The hydroid B. muscus is widely distributed around the British Isles. It favours sheltered waters and is tolerant of low salinity levels. The medusae have been recorded around the coasts of Britain, the North Sea, Norway, south-west Ireland, the Isles of Scilly, the Bay of Biscay, the Mediterranean Sea and near Rhode Island in the United States.
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The most commonly encountered organisms include ctenophores, medusae, salps, and Chaetognatha in coastal waters. However, almost all marine phyla, including Annelida, Mollusca and Arthropoda, contain gelatinous species, but many of those odd species live in the open ocean and the deep sea and are less available to the casual ocean observer. (2007) The Deep. University of Chicago Press.
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From this point, if conditions are favorable, they will undergo a process known as strobilation occurs. This is when the polyp asexually produces the ephyrae into the water which then develop into the medusae. If conditions are not favorable, the polyps will continue in their benthic stage where they will wait for the return of favorable conditions.
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Fossils from Monte Bolca, a lagerstätte near Verona, were originally named Zoophycos caput-medusae and previously thought to be trace fossils, but were later found to be plants instead and given the name Algarum by French zoologist Henri Milne-Edwards in 1866. The type specimen collected by Italian paleobotanist Abramo Bartolommeo Massalongo before 1855 is at the Natural History Museum of Verona and was preserved in a lithographic limestone upper and lower slab. When Italian botanist Achille Forti (1878–1937) worked on the specimens in 1926, they were reinterpreted as close relatives of Postelsia, now known to be a brown algae, which had lived in the coastal waters of the Eocene sea. Forti renamed the species Postelsiopsis caput-medusae commemorating the fossils' extreme similarity to the extant Postelsia palmaeformis.
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Cubozoans follow a life cycle that alternates between young benthic sessile polyps and adult motile pelagic medusae. The cycle begins with a planula larvae. This planula will continue to swim until it finds a substrate that it can use as support. Once the planula attaches to a substrate like a coral reef or rock, the organism will morph into a polyp.
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This organism has a benthic polyp stage before developing into a pelagic adult medusae. Compass jellyfish consume a variety of marine invertebrates and plankton and are preyed on by very few. C. hysoscella contribute to the global issue of jellyfish overpopulation which is concerning to humans for various reasons including recreational interference, economic turmoil for fishing communities, and depleted fish resources.
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In Gulf waters, the medusae grow to unusually large size, upwards of across. In July 2007 smallish individuals were seen in Bogue Sound much further north along the North Carolina coast. However, their ability to consume plankton and the eggs and larvae of important fish species is cause for concern. Each jellyfish can filter as much as of seawater per day.
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The jellyfish is almost entirely 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.
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These provide much of the organic carbon needed by the fire coral. The reproduction of fire corals is complex and involves an alternation of asexual and sexual generations. The encrusting parts of the coral expand by the growth of stolons, and the edges of blades expand by sympodial growth. Sexual reproduction involves a sessile polyploid stage and the budding off of planktonic medusae.
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The small pectoral fins move constantly to control pitch, while the clavus is employed as a rudder. Juvenile sharptail molas are known to feed on benthic annelids and sponges. Adults likely feed on medusae, siphonophores, ctenophores, and salps, as well as some fishes, crustaceans, and molluscs. Sharptail molas sometimes have remoras attached to the surface of their bodies or inside their buccal cavities.
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He was once a criminal, and can open any lock ever made. In his youth he was called Giles The Ghost. Jay Kalam (Commander of The Legion) and Hal Samdu are the names of the other two warriors. In this story, these warriors of the 30th Century battle the Medusae, the alien race from the lone planet of Barnard's Star.
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Evidence for equatorial hydration is both morphological and compositional and is seen at both the Medusae Fossae formation and the Tharsis Montes. Analysis of the data suggests that the southern hemisphere may have a layered structure, suggestive of stratified deposits beneath a now extinct large water mass. Blocks in Aram showing a possible ancient source of water. Location is Oxia Palus quadrangle.
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This weapon of mass destruction was entrusted to a series of women. AKKA was used in the past to overthrow the Purple tyranny. In this story the Medusae tried to steal the secret weapon, but failed and their invasion force was destroyed. When they were wiped out, the Moon, where they had established their base, was erased out of existence.
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The medusae reach up to in diameter with the bell height 3–4 times less than the width. Specimens found in the northern waters tend to be transparent, while those found farther south are tinted pink. The broad stomach gives rise to 80–100 non-branching radial canals. Tentacles are slightly more numerous than radial canals and do possess elongated conical bulbs.
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The eggs develop in gonads of female medusae, which are located in the walls of the manubrium (stomach). Mature eggs are presumably spawned and fertilized in the sea by sperm produced and released by male medusae, as is the case for most hydromedusae, although the related species Turritopsis rubra seems to retain fertilized eggs until the planula stage. Fertilized eggs develop into planula larvae, which settle onto the sea-floor (or even the rich marine communities that live on floating docks), and develop into polyp colonies (hydroids). The hydroids bud new jellyfishes, which are released at about one millimetre in size and then grow and feed in the plankton, becoming sexually mature after a few weeks (the exact duration depends on the ocean temperature; at it is 25 to 30 days and at it is 18 to 22 days).
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Continuing up the food chain, T. vagina is preyed upon by medusae, siphonophores, ctenophores, heteropods, sea turtles, late stage larvae of the spiny lobster, marine birds, along with various species of fish. They have a high energy content at (11.00 kJ g−1 DW). In a study done in the Japan Sea in 2006, the gut contents of T. vagina where evaluated. The diatom Coscinodiscus spp.
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Tverd's level of development is mostly equal to the Late Medieval period of Demos history. The significant exceptions are the fields of biotechnology and genetics. Most devices and appliances are made from living things. For example, genetically modified medusae are used to create the Tverd equivalent of contact lenses, which can also be used to see certain wavelengths invisible to the naked eye (e.g. infrared).
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The animals remain attached to the substrate by a stalk at the opposite end from the mouth. Staurozoans can be regarded as large polyps that have partially differentiated into sexually mature medusae. These spawn gametes which develop into non-swimming planulae that crawl away to new locations. Hydrozoa is a large group of solitary and colonial cnidarians from both marine and freshwater environments worldwide.
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They are not further identifiable from what Aristotle says but some pulmones appear in Pliny as a class of insensate sea animal;Natural History IX.71. specifically the halipleumon ("salt-water lung").Natural History XXXII.32. William Ogle, a major translator and annotator of Aristotle, attributes the name sea-lung to the lung-like expansion and contraction of the Medusae, a kind of Cnidaria, during locomotion.
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Jellyfish have a complex life cycle which includes both sexual and asexual phases, with the medusa being the sexual stage in most instances. Sperm fertilize eggs, which develop into larval planulae, become polyps, bud into ephyrae and then transform into adult medusae. In some species certain stages may be skipped. Upon reaching adult size, jellyfish spawn regularly if there is a sufficient supply of food.
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After some time drifting with the current, they settle onto the seabed, undergo metamorphosis and become sedentary. The smallest polyps that form, under 1 millimetre (0.04 in) long, have 2 tentacles while older, larger ones have 3 to 5. The polyps can reproduce asexually, budding to form either more polyps or free-swimming medusae. A polyp can have several buds forming at any one time.
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As medusae, they eat a variety of crustaceans and fish, which they capture using stinging cells called nematocysts. The nematocysts are located throughout the tentacles that radiate downward from the edge of the umbrella dome, and also cover the four or eight oral arms that hang down from the central mouth. Some species, however, are instead filter feeders, using their tentacles to strain plankton from the water.
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Aequorea medusae are eaten by the voracious scyphozoa Cyanea capillata, commonly called the Lion's Mane Jelly, as well as ctenophores, siphonophora and other hydromedusae, including documented cases of cannibalism. Many larger specimens are found with the parasitic hyperiid amphipod Hyperia medusarum attached to the either the subumbrella or exumbrella; these amphipods may burrow into the jelly, but such activities are not lethal to the jellyfish.
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After a week, planulae develop into tiny ephyrae and a month later they develop into (male or female) medusae. There is little or no ephyra growth at temperatures below , and fewer survive below . The bottom-living polyp stage of most other jellyfish species is in between the planula and ephyra stages. Initially, the medusa of P. noctiluca only has a bell diameter of about .
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Climactichnites burrow Krukowski Quarry is a sandstone quarry near Mosinee, Wisconsin. In the late Cambrian period (510 m.y.a), this area was a beach and shoreline, and the quarry is well known for abundant fossil impressions of Climactichnites, Protichnites, and beached jellyfish, Scyphozoan Medusae. Pre- Devonian evidence of this jellyfish is exceedingly rare; this location and one in New Brunswick hold the only known fossils.
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Many cnidarian species produce colonies that are single organisms composed of medusa-like or polyp- like zooids, or both (hence they are trimorphic). Cnidarians' activities are coordinated by a decentralized nerve net and simple receptors. Several free- swimming species of Cubozoa and Scyphozoa possess balance-sensing statocysts, and some have simple eyes. Not all cnidarians reproduce sexually, with many species having complex life cycles of asexual polyp stages and sexual medusae.
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In medusae the only supporting structure is the mesoglea. Hydra and most sea anemones close their mouths when they are not feeding, and the water in the digestive cavity then acts as a hydrostatic skeleton, rather like a water-filled balloon. Other polyps such as Tubularia use columns of water-filled cells for support. Sea pens stiffen the mesoglea with calcium carbonate spicules and tough fibrous proteins, rather like sponges.
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The National Marine Biological Library at the Marine Biological Association retains much of Russell's scientific and personal papers for the period 1921-1984.Sir Frederick Stratten Russell F.R.S. MBA Archive Collection Russell studied the life histories and distribution of plankton. He also discovered a means of distinguishing between different species of fish shortly after they have hatched. He was the author of The Medusae of the British Isles (1953–1970).
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At the mercy of winds and currents, chondrophores are pelagic and drift in the open ocean. They are often seen in large aggregations; mass beachings are not unusual. Chondrophores multiply by releasing tiny (0.3-2.5 millimetres or 0.01-0.09 inches) medusae which go on to develop new colonies. Velella differs from Porpita by their transparent, membranous sail-shaped floats; filled with gas, the membranes have a texture reminiscent of cellophane.
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Also, P. camtschatica is sometimes confused with the Lion's mane jellyfish (Cyanea capillata). It feeds primarily by collecting medusae and plankton with its tentacles, and bringing them into its mouth for digestion. It is capable of only limited motion, and mostly drifts with the current, even when swimming. This species and most of its relatives in the Cnidaria phylum often use suspension feeding as their main food gathering strategy.
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Revision of Taeniatherum (Poaceae). Nordic Journal of Botany 6(4): 389–397 The only recognized species is Taeniatherum caput-medusae and is native to southern and central Europe (from Portugal to European Russia), North Africa (Algeria, Morocco, Tunisia), and Asia (from Turkey + Saudi Arabia to Pakistan + Kazakhstan).Kew World Checklist of Selected Plant FamiliesAltervista Flora Italiana genere TaeniatherumDanin, A. (2004). Distribution Atlas of Plants in the Flora Palaestina area: 1–517.
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Chrysaora pacifica, commonly named the Japanese sea nettle, is a jellyfish in the family Pelagiidae. This common species is native to the northwest Pacific Ocean, including Japan and Korea, but it was formerly confused with the larger and more northerly distributed C. melanaster. As a consequence, individuals kept in public aquariums have often been mislabelled as C. melanaster. The medusae of C. pacifica typically has a bell with a diameter of .
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The manubrium of the medusae is short. They lack a gastric peduncle, ocelli (making them effectively blind) and excretory pores, and have 4 simple radial canals and in adults at least 16 statocysts. The tentacles at their margin are hollow and at the side carry cirri; cirri are lacking from around the margin however. The gonads are located at the radial canals; they do not reach the manubrium.
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One of the more interesting puzzles in ichnotaxonomy, pertains to fossils from Monte Bolca, originally named Zoophycos caput-medusae, previously thought to be trace fossils, were found to be plants instead and given the name Algarum by French zoologist Henri Milne- Edwards in 1866. The type specimen collected by Italian paleobotanist Abramo Bartolommeo Massalongo before 1855 is at the Natural History Museum of Verona and was preserved in a lithographic limestone upper and lower slab. When Italian botanist Achille Forti (28 November 1878 Verona -11 February 1937 Verona) worked on the specimens in 1926, they were reinterpreted as close relatives of the sea palm, now known to be a brown algae, which had lived in the coastal waters of the Eocene sea. He renamed the species Postelsia caput- medusae which makes it related to the genus Postelsia, now with only one living species, which was described by its discoverer Franz Josef Ruprecht in 1852 as Postelsia palmaeformis.
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Members of this family have bell-shaped medusae with a four-part manubrium or sub-umbrella, a mouth with four plain or pleated lips and four, often broad, radial canals. The gonads are smooth or folded and positioned on the walls of the manubrium and sometimes extend onto the radial canals. There are fine, hollow tentacles along the margin of the bell, mostly growing from small carrot-shaped bulbs. The hydroids have threadlike tentacles.
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Like other Scyphozoans, Chrysaora hysoscella undergo metamorphosis as the organism develops and experiences a polyp and then medusa form. Females release planular larvae which swim to find a suitable place to settle. The planulae attach to a benthic substrate and develop into a sessile polyp which releases immature medusae through asexual reproduction called strobilation. Chrysaora hysoscella function as a male upon maturity and then develop female gametes, meaning this organism is protandrously hermaphroditic.
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Anthozoan larvae either have large yolks or are capable of feeding on plankton, and some already have endosymbiotic algae that help to feed them. Since the parents are immobile, these feeding capabilities extend the larvae's range and avoid overcrowding of sites. Scyphozoan and hydrozoan larvae have little yolk and most lack endosymbiotic algae, and therefore have to settle quickly and metamorphose into polyps. Instead, these species rely on their medusae to extend their ranges.
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In patients with portal hypertension, the paraumbilical veins may become enlarged in order to reduce hepatic portal vein pressure by shunting blood to the superficial epigastric vein. The superficial epigastric vein drains to the femoral vein which ultimately drains into the inferior vena cava directly through the external iliac and common iliac vein, thereby bypassing the liver. Dilation of this particular portacaval anastomosis results in what is referred to as caput medusae.
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The elasticity causes the work done against the water to be low because of the large openings the water has to enter and the small openings the water has to leave. The inertial work of scallop jet-propulsion is also low. Because of the low inertial work, the energy savings created by the elastic tissue is so small that it's negligible. Medusae can also use their elastic mesoglea to enlarge their bell.
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Bougainvillia is a genus of hydroids in the family Bougainvilliidae in the class Hydrazoa. Members of the genus are characterised by having the marginal tentacles of their medusae arranged in four bundles. Some species are solitary and others are colonial but all are filter feeders. They are found in the Southern Ocean, having a circumpolar distribution, but some species also occur in the Northern Hemisphere, possibly travelling there as polyps on the hulls of ships.
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The medusae of most species are fast growing, mature within a few months and die soon after breeding, but the polyp stage, attached to the seabed, may be much more long- lived. Jellyfish have been in existence for at least 500 million years,Fossil Record Reveals Elusive Jellyfish More Than 500 Million Years Old . ScienceDaily (2 November 2007). and possibly 700 million years or more, making them the oldest multi-organ animal group.
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Nevertheless, high concentration of planktonic organisms within LC can attract birds and fish. Schools of White Bass Roccus chrysops were observed feeding upon Daphnia along the foam track. In contrast, lesser Flamingoes Phoeniconaias minor were observed feeding on bubble lines containing concentrated blue-green algae. Similarly, medusae were found to aggregate in linear pattern (average spacing of 129 m) parallel with wind in the Bering Sea which could be due to large LCs.
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Cnidarian species are found in one of two body forms: the polyp and the medusae. Some alternate between these two forms during their life cycle. In the case of Aiptasia, and all anthozoans, the body form is the polyp. The body is composed of a pedal disc with which Aiptasia attaches to the substrate, a smooth and elongated body column and an oral disc which bears the mouth and long stinging tentacles.
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Rangelands 22:6 3–6. The subspecies caput-medusae is a native species to Europe, and is mostly restricted to Spain, Portugal, southern France, Algeria, and Morocco. Subspecies crinitum is found from Greece and the Balkans east into Asia, and the range of subspecies asperum completely overlaps the other two subspecies. In Asia, medusahead is widespread in Turkmenistan, Iran, Syria, and in the northern portion of Israel, inhabiting low mountains and plateau areas.
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229-231 Among the notable prints are numerous radiolarians, which Haeckel helped to popularize among amateur microscopists; at least one example is found in almost every set of 10. Cnidaria also feature prominently throughout the book, including sea anemones as well as Siphonophorae, Semaeostomeae, and other medusae. The first set included Desmonema annasethe (now Cyanea annasethe), a particularly striking jellyfish that Haeckel observed and described shortly after the death of his wife Anna Sethe.
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C. marsupialis, illustration from Medusae of the World, vol. 3, by A.G. Mayer Carybdea marsupialis is a predator and feeds on invertebrates and even small fish which it captures with the nematocysts (stinging cells) in its tentacles, often in shallow waters. It swims by making rapid contractions of the bell and can move at a speed of between per minute. Like other species in its genus it has comparatively sophisticated eyes with lenses.
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As a planula settles down, it gives rise to a colony of polyps that are attached to the sea-floor. All the polyps and jellyfish arising from a single planula are genetically identical clones. The polyps form into an extensively branched form, which is not commonly seen in most jellyfish. Jellyfish, also known as medusae, then bud off these polyps and continue their life in a free-swimming form, eventually becoming sexually mature.
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Genomic analyses such as sequence analysis on mRNA or mitochondria DNA have been employed to investigate its lifecycle. mRNA analysis of each life stage showed that a stage-specific gene in the medusae stage is expressed tenfold more than in other stages. This gene is relative to a Wnt signal that can induce a regeneration process upon injury. Analysis of nucleotide sequence homologs and protein homologs identified Nemopsis bachei as the species' closest relative.
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Ohdera et al:Upside- Down but Headed in the Right Direction: Review of the Highly Versatile Cassiopea xamachana System. The life cycle of Cassiopea xamachana alternates between a polyp phase and the medusa phase. Gametes are released by the medusae into the water and the fertilized eggs hatch into planula larvae, which attach to the sea bed or some other suitable substrate. Decomposing red mangrove (Rhizophora mangle) give off a substance which attracts the larvae to settle.
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Other threats include degradation of the habitat by invasive species of plants such as Centaurea solstitialis, the yellow starthistle. Other noxious weeds in the habitat include Chondrilla juncea (rush skeletonweed), Taeniatherum caput- medusae (medusahead), and Cirsium arvense (Canada thistle). Logging has caused damage to the habitat via soil disruption; however, careful selective logging may clear some of the overgrowth caused by fire suppression. Livestock grazing injures the leaves of the rare plant, reducing its reproductive potential.
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Their distinguishing feature is cnidocytes, specialized cells that they use mainly for capturing prey. Their bodies consist of mesoglea, a non-living jelly-like substance, sandwiched between two layers of epithelium that are mostly one cell thick. They mostly have two basic body forms: swimming medusae and sessile polyps, both of which are radially symmetrical with mouths surrounded by tentacles that bear cnidocytes. Both forms have a single orifice and body cavity that are used for digestion and respiration.
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Members of the Hyperiidea are all planktonic and marine. Many are symbionts of gelatinous animals, including salps, medusae, siphonophores, colonial radiolarians and ctenophores, and most hyperiids are associated with gelatinous animals during some part of their life cycle. Some 1,900 species, or 20% of the total amphipod diversity, live in fresh water or other non-marine waters. Notably rich endemic amphipod faunas are found in the ancient Lake Baikal and waters of the Caspian Sea basin.
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It was also used to wipe out most of the Medusae, though they had tried to steal the secret. When they were wiped out, the Moon where they had established their base was erased out of existence. At the end of the story, John Ulnar falls in love with the keeper of AKKA, Aladoree Anthar, and marries her. Aladoree Anthar is described as a young woman with lustrous brown hair and gray eyes, beautiful as a goddess.
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Aequorea victoria are found along the North American west coast of the Pacific Ocean from the Bering Sea to southern California. The medusa part of the life cycle is a pelagic organism, which is budded off a bottom-living polyp in late spring. The medusae can be found floating and swimming both nearshore and offshore in the eastern Pacific Ocean;Kozloff, Eugene N. Marine Invertebrates of the Pacific Northwest. 2nd. Seattle: University of Washington Press, 1996.
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The medusae of hydrozoans are smaller than those of typical jellyfish, ranging from in diameter. Although most hydrozoans have a medusoid stage, this is not always free-living, and in many species, exists solely as a sexually reproducing bud on the surface of the hydroid colony. Sometimes, these medusoid buds may be so degenerated as to entirely lack tentacles or mouths, essentially consisting of an isolated gonad. The body consists of a dome-like umbrella ringed by tentacles.
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Bulbophyllum medusae, commonly known as the Medusa orchid, is a species of epiphytic orchid with a creeping rhizome and a single leaf about long emerging from the top of each pseudobulb. The flowers are creamy yellow and arranged in clusters of about fifteen arranged in a circle at the tip of the flowering stem. The flowers have an unpleasant odour. The flowers have thread-like lateral sepals about long, giving each cluster the appearance of Medusa.
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Cnidarian sexual reproduction often involves a complex life cycle with both polyp and medusa stages. For example, in Scyphozoa (jellyfish) and Cubozoa (box jellies) a larva swims until it finds a good site, and then becomes a polyp. This grows normally but then absorbs its tentacles and splits horizontally into a series of disks that become juvenile medusae, a process called strobilation. The juveniles swim off and slowly grow to maturity, while the polyp re-grows and may continue strobilating periodically.
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Mayor's most recognized work originated from his work as a successful marine biologist. He published his first book about jellyfish in 1910 titled Medusae of the World, which documented his many studies of species of jellyfish around the world. In 1907 Mayor founded the Tortugas Laboratory on Garden Key (today Fort Jefferson National Monument), maintained by the Carnegie Institution for Science, where each summer marine biologists studied the life of the coral reef. Mayor died on nearby Loggerhead Key, Dry Tortugas, aged 54.
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Symptoms usually are contained to a single year on conifers, shedding the affected needles in fall. To survive the winter Melampsora medusae remain as teliospores on the dead leaves of the host, coming back in the spring to be spread by the wind as basidiospores, and infecting new conifers. After about two weeks, aeciospores are produced on the coniferous needles. Those spores serve as inoculum for an infection in live trembling aspen and other poplar trees in another two weeks.
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DVA in MRI (T1 axial contrast enhanced) In up to 30% there is a coincidence of CCM with a venous angioma, also known as a developmental venous anomaly (DVA). These lesions appear either as enhancing linear blood vessels or caput medusae, a radial orientation of small vessels that resemble the hair of Medusa from Greek mythology. These lesions are thought to represent developmental anomalies of normal venous drainage. These lesions should not be removed, as venous infarcts have been reported.
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The name jellyfish, in use since 1796, has traditionally been applied to medusae and all similar animals including the comb jellies (ctenophores, another phylum). The term jellies or sea jellies is more recent, having been introduced by public aquaria in an effort to avoid use of the word "fish" with its connotations of an animal with a backbone, though shellfish, cuttlefish and starfish are not vertebrates either.Flower Hat Jelly, New York Aquarium. In scientific literature, "jelly" and "jellyfish" have been used interchangeably.
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Praya dubia zooids arrange themselves in a long stalk—usually whitish and transparent (though other colours have been seen)—known as a physonect colony. The larger end features a transparent, dome-like float known as a pneumatophore, filled with gas which provides buoyancy, allowing the organism to remain at its preferred ocean depth. Next to it are the nectophore, powerful medusae which pulsate in rhythmic coordination which propel Praya dubia through ocean waters. Together, the array is known as the nectosome.
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Research suggests that the implied methane destruction lifetime is as long as ≈ 4 Earth years and as short as ≈ 0.6 Earth years. This unexplained fast destruction rate also suggests a very active replenishing source. A team from the Italian National Institute for Astrophysics suspects that the methane detected by the Curiosity rover may have been released from a nearby area called Medusae Fossae Formation located about 500 km east of Gale crater. The region is fractured and is likely volcanic in origin.
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In contrast, crown rot had the greatest impact on water-stressed plants and therefore may be an effective biological control of grassy weeds in the arid regions of the western U.S. It is also promising because it did not have a significant negative impact on desirable grasses such as western wheatgrass.Grey, W.E., et al. (1995). Potential for biological control of downy brome (Bromus tectorum) and medusahead (Taeniatherum caput-medusae) with crown and root rot fungi. Weed Technology 9:2 362–365.
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Parts of the coral may get detached from the colony by a storm or other means, and some of these fragments may end up in suitable locations to grow into new colonies which will be genetically identical to the parent colony. This fragmentation is probably the most frequent method of reproduction. Alternatively, certain pores called ampullae contain polyps that bud off short-lived, jellyfish-like medusae, which separate from the colony. They produce gametes which, after fertilisation, develop into planula larvae.
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These snails are pelagic and live at the surface of the ocean. Adult snails may not be capable of swimming, and die when they are detached from their rafts; Janthina janthina larvae, however, actively swim in the water column. The adult snails prey upon (and live near to) one of several species of pelagic animals loosely known as jellyfish. More specifically they eat the medusae of free-swimming Cnidaria, in particular the genus known as "by-the-wind sailors", Velella.
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In people with kidney failure, requiring dialysis, a cimino fistula is often deliberately created in the arm by means of a short day surgery in order to permit easier withdrawal of blood for hemodialysis. As a radical treatment for portal hypertension, surgical creation of a portacaval fistula produces an anastomosis between the hepatic portal vein and the inferior vena cava across the omental foramen (of Winslow). This spares the portal venous system from high pressure which can cause esophageal varices, caput medusae, and hemorrhoids.
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Polymorphism refers to the occurrence of structurally and functionally more than two different types of individuals within the same organism. It is a characteristic feature of Cnidarians, particularly the polyp and medusa forms, or of zooids within colonial organisms like those in Hydrozoa. In Hydrozoans, colonial individuals arising from individuals zooids will take on separate tasks. For example, in Obelia there are feeding individuals, the gastrozooids; the individuals capable of asexual reproduction only, the gonozooids, blastostyles and free-living or sexually reproducing individuals, the medusae.
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Her body is later used by the Snake of The Clearing Eyes so that he might able to use her power to find a perfect vessel for him which is Konoha, In the end, she finally able to peacefully die with Shion by her side, finally freed from the torture she has been suffering for very many years. Her song is . ; / : :Ayaka is Ayano's mother, Kenjirō's wife and Hiyori's sister. She became interested in the myth about Medusae and fell in love with Kenjirō at university.
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Fossil jellyfish, Rhizostomites lithographicus, one of the Scypho-medusae, from the Kimmeridgian (late Jurassic, 157 to 152 mya) of Solnhofen, Germany Stranded scyphozoans on a Cambrian tidal flat at Blackberry Hill, Wisconsin. The conulariid Conularia milwaukeensis from the Middle Devonian of Wisconsin. Since jellyfish have no hard parts, fossils are rare. The oldest conulariid scyphozoans appeared between 635 and 577 mya in the Neoproterozoic of the Lantian Formation in China; others are found in the youngest Ediacaran rocks of the Tamengo Formation of Brazil, c.
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Discoidal fossils had been classified as cnidarian medusae before being redefined as holdfasts of frondose organisms, that is, the roots or stalks that held them to the sea bed. Rangeomorphs consist of branching "frond" elements, each a few centimeters long, each of which is itself composed of many smaller branching tubes held up by a semi-rigid organic skeleton. This self-similar structure proceeds over four levels of fractality, and could have been formed using fairly simple developmental patterns. Rangeomorphs were radially symmetrical and likely sessile.
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A few groups – mainly catenulids and seriates – have statocysts, fluid-filled chambers containing a small solid particle or, in a few groups, two. These statocysts are thought to be balance and acceleration sensors, as that is the function they perform in cnidarian medusae and in ctenophores. However turbellarian statocysts have no sensory cilia, and it is unknown how they sense the movements and positions of the solid particles. Most species have ciliated touch-sensor cells scattered over their bodies, especially on tentacles and around the edges.
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A few large species have many eyes in clusters over the brain, mounted on tentacles, or spaced uniformly around the edge of the body. The ocelli can only distinguish the direction from which light is coming to enable the animals to avoid it. A few groups have statocysts - fluid-filled chambers containing a small, solid particle or, in a few groups, two. These statocysts are thought to function as balance and acceleration sensors, as they perform the same way in cnidarian medusae and in ctenophores.
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The fossil resembles several others, particularly Ectenocrinus simplex. This comparison was made by Gürich, who compared the tubes to the likeness of the arms of the crinoids.Mikhail Fedonkin, classified O. parallelum as a quilted petalonam because of its unique preservation. “They resemble sand-filled rocks which were composed of several tubes, often constricted midway by a prominent surface, but what these structures represent is uncertain.” J. John Sepkoski classified Orthogonium as a member of the subphylum Medusae with sister taxa including Bonata, Inaria, and Bronicella.
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Aequorea forskalea is synonymous with many different findings from 1775-1938. Even though it may have only been called A. forskalea in 1810, it was still discovered in 1775 as Aequorea aequorea. A reputable marine biologist, Frederick Stratten Russell, authored the book The Medusae of the British Isles in 1953 where he stated that A. forskalea was the acceptable name for these species, and that A. aequorea was a name reserved for an unidentifiable species. One notably similar species, A. victoria is found abundantly in the Pacific.
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The scientists used data from continuing reconnaissance of Mars using the old Mars Odyssey Orbiter and the Mars Reconnaissance Orbiter, discovered 139 LARLE craters ranging in diameter from 1.0 to 12.2 km, with 97 per cent of the LARLE craters are found poleward of 35N and 40S, while remaining mainly traced in the equatorial Medusae Fossae Formation. LARLE craters are characterized by a crater and normal layered ejecta pattern surrounded by an extensive but thin outer deposit which ends in a flame-like shape.
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The seeds are primarily those of grass species, and some preferred forb species. Indian ricegrass (Oryzopsis hymenoides), cheatgrass (Bromus tectorum), Russian-thistle (Salsola kali), antelope bitterbrush (Purshia tridentata), pigweed (Amaranthus spp.), and mustard (Brassica spp.) seeds are important Great Basin pocket mouse food items. In productive years, cheatgrass seeds formed a major portion of the diet of Great Basin pocket mice in southeastern Washington. Seeds of medusahead (Taeniatherum caput-medusae) were not used by Great Basin pocket mice in Lassen County, California, and areas with heavy medusahead invasion were avoided.Longland, William S. 1994.
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Small fish are one of the prey types pursued by the pelagic stingray. The pelagic stingray is an active predator that captures prey by wrapping its pectoral fins around it, before manipulating it to the mouth. It is the only stingray in which both sexes have pointed teeth, for grasping and cutting into slippery prey. A wide variety of organisms are represented in its diet: crustaceans including amphipods, krill, and larval crabs, molluscs including squid, octopus, and pteropods, bony fishes including herring, mackerel, sea horses and filefish, comb jellies and medusae, and polychaete worms.
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The circulation of nutrients is driven by water currents produced by cilia in the gastroderm or by muscular movements or both, so that nutrients reach all parts of the digestive cavity. Nutrients reach the outer cell layer by diffusion or, for animals or zooids such as medusae which have thick mesogleas, are transported by mobile cells in the mesoglea. Indigestible remains of prey are expelled through the mouth. The main waste product of cells' internal processes is ammonia, which is removed by the external and internal water currents.
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If the body tilts in the wrong direction, the animal rights itself by increasing the strength of the swimming movements on the side that is too low. Most species have ocelli ("simple eyes"), which can detect sources of light. However, the agile box jellyfish are unique among Medusae because they possess four kinds of true eyes that have retinas, corneas and lenses. Although the eyes probably do not form images, Cubozoa can clearly distinguish the direction from which light is coming as well as negotiate around solid-colored objects.
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Deposits of the Medusae Fossae Formation lie both over and under lavas, suggesting the deposition of this formation was contemporaneous with volcanism. Statistics of small craters indicate lavas in the western Cerberus plains may be less than a million years old, but the model isochrons may be unreliable if the small crater population is dominated by secondary craters (craters formed by material ejected from larger impacts). Images showing no large craters with diameters larger than 500 meters superimposed on western Cerberus plains lavas indicate the same surface is younger than 49 Ma (million years).
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Jellyfish tend to be very efficient when they swim, which means that on a given amount of energy they can go further than many other animals can. As one of the simplest multicellular organisms, jellyfish (medusae) contract cells to generate jet forces. By mathematically analyzing the fluid vortex rings that form as a result of the contraction, Dabiri was able to model the formation of optimal vortex rings.. Flow patterns generated by oblate medusan jellyfish: field measurements and laboratory analyses. Journal of Experimental Biology. Accepted 31 January 2005.
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The fungus cause large cankers to form and a disease known as larch canker which is particularly harmful to the tamarack larch, killing both young and mature trees.European larch canker Natural Resources Canada Apart from this, the only common foliage diseases are rusts, such as the leaf rust in eastern and central North America. However, this rust, caused by the fungus Melampsora medusae, and other rusts do little damage to tamarack. The needle-cast fungus Hypodermella laricis has attacked tamarack in Ontario and has the potential for local damage.
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Aurelia aurita and other Aurelia species feed on plankton that includes organisms such as mollusks, crustaceans, tunicate larvae, rotifers, young polychaetes, protozoans, diatoms, eggs, fish eggs, and other small organisms. Occasionally, they are also seen feeding on gelatinous zooplankton such as hydromedusae and ctenophores. Both the adult medusae and larvae of Aurelia have nematocysts to capture prey and also to protect themselves from predators. The food is caught with its nematocyst-laden tentacles, tied with mucus, brought to the gastrovascular cavity, and passed into the cavity by ciliated action.
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Most species of Scyphozoa have two life-history phases, including the planktonic medusa or jellyfish form, which is most evident in the warm summer months, and an inconspicuous, but longer-lived, bottom-dwelling polyp, which seasonally gives rise to new medusae. Most of the large, often colorful, and conspicuous jellyfish found in coastal waters throughout the world are Scyphozoa. They typically range from in diameter, but the largest species, Cyanea capillata can reach across. Scyphomedusae are found throughout the world's oceans, from the surface to great depths; no Scyphozoa occur in freshwater (or on land).
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Unlike most medusae, they lack marginal tentacles. Specimens so far found reach almost 10 cm in diameter, which is large for a scyphomedusa. The bell is blue-white in colour. The exumbrella is white, and this and the four oral arms are covered with large nematocyst-laden projections filled with stinging cells, enabling the jelly to capture food items of a variety of sizes; it seems to prefer large prey, up to half its size, which is unusual in jellies that capture prey with their bells rather than with tentacles.
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The African pompano is a schooling predatory fish which takes predominantly a variety of crustaceans, including decapods, carids and copepods, as well as cephalopods and small fish. They are preyed upon by larger fish, including mackerel and tunas, as well as sharks. The small pelagic juveniles' filamentous dorsal and anal fins resemble jellyfish medusae, and this mimicry may gain them some protection from predators. Little is known of their reproductive habits and maturation lengths, although a study in India determined a peak in the abundance of A. ciliaris larvae in April.
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The Indian threadfish is a predatory fish, consuming of a wide range of fishes, small squids, jellyfish and crustaceans. As with A. ciliaris, the trailing fins of juveniles are thought to resemble jellyfish medusae, causing predators to avoid the young fish. Relatively little is known about reproduction in the species, although observations made in Indonesia show spawning occurs in pairs at daytime between ebbing and flooding tides. The spawning area in this instance was a shoal of 35–45 m, located in a deeper channel between two islands.
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C. sowerbii medusae are about 20–25 mm (approximately 1 in.) in diameter, somewhat flatter than a hemisphere, and very delicate, when fully grown. They have a whorl of up to 400 tentacles tightly packed around the bell margin. Hanging down from the center of the inside of the bell is a large stomach structure called a manubrium, with a mouth-opening with four frilly lips. Circulation of nutrients is facilitated by four radial canals which originate at the edges of the stomach (manubrium), and which are also connected to a ring canal, located near the bell margin.
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Kenjirō was interested in the theory of Medusae and researched it with Ayaka, only to be caught in a landslide with her and die. He came in contact with the Heat Haze and was possessed by the snake of 'Clearing Eyes'. He became much more engrossed in research after Ayaka's death, eventually experimenting on and killing his two students (Takane and Haruka), this was done while possessed by the snake of 'Clearing Eyes'. His fate is that he dies and reunites with Ayaka in the Heat Haze; in Route XX, the snake of 'Clearing Eyes' (while it is possessing Konoha) kills him.
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Close-up of B. conifera Although B. conifera may appear to be an individual organism, each specimen is in fact a colonial organism composed of medusoid and polypoid zooids that are morphologically and functionally specialized. Zooids are multicellular units that develop from a single fertilized egg and combine to create functional colonies able to: reproduce, digest, float, and maintain body positioning. It has a cystonect body plan, meaning it has a pneumatophore, or float, and siphosome, or line of polyps, but no nectosome, or propulsion medusae. Without that propulsion, B. conifera moves through contracting and relaxing the body stem.
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Aurelia aurita (also called the common jellyfish, moon jellyfish, moon jelly or saucer jelly) is a widely studied species of the genus Aurelia. All species in the genus are closely related, and it is difficult to identify Aurelia medusae without genetic sampling; most of what follows applies equally to all species of the genus. The most common method used to identify the species consists of selecting a jellyfish from a harbour using a device, usually a drinking glass and then photographing the subject. This means that they can be released in to the harbour shortly afterwards and return to their natural habitat.
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Physalia physalis, Portuguese man-of-war, is a marine colonial animal that is dioecious; the reproductive medusae within a colony such as this are all of the same sex. In zoology, dioecious species may be opposed to hermaphroditic species, meaning that an individual is of only one sex, in which case the synonym gonochory is more often used. Dioecy may also describe colonies within a species, such as the colonies of Siphonophorae (Portuguese man-of-war), which may be either dioecious or monoecious. An individual dioecious colony contains members of only one sex, whereas monoecious colonies contain members of both sexes.
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The taxon was erected by Danish marine biologist Paul Lassenius Kramp in 1938 to accommodate certain families of hydrozoans with biphasic life histories. It includes genera with medusae with ecto-endodermal statocysts and with gonads alongside their radial canals, and also genera which have polyps that are not covered by a theca. Molecular analysis performed by Collins in 2006 has since shown that the Limnomedusae are not monophylic. The family Armorhydridae, which contains a single genus and a single species, Armorhydra janowiczi, is found living in coarse sediment, has hollow tentacles and has no radial canals.
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Aequorea victoria juvenile medusae are asexually budded off hydroid colonies in late spring; these free-living hydromedusae will spend all of their lives in the plankton. The medusa spends its first stage of life growing quickly, and after reaching approximately 3 cm will begin producing gametes for reproduction. Each medusa is either a male or a female. The eggs and spermatozoa mature daily in the medusa gonads, given enough food, and are free-spawned into the water column in response to a daily light cue, where they are fertilized and eventually settle out to form a new hydroid colony.
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Merrin is in fact a psychopath, but also an extremely brilliant, former Legionnaire who once subjected Bob Star to horrific torture with the help of the Iron Confessor device developed by the "Reds" of Old Earth. Kalam tells Bob that an entrepreneur, Edward Orco, found in space a life-support space capsule with a child inside who Orco adopted under the name Stephen. Stephen Orco, after being graduated from the Academy, was assigned to Callisto. There he created a vortex gun based on the plasma weapons of the Medusae, and raised a revolt against the Green Hall.
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Some star atlases during the early 19th century also depicted Perseus holding the disembodied head of Medusa, whose asterism was named together as Perseus et Caput Medusae; however, this never came into popular usage. The galactic plane of the Milky Way passes through Perseus, whose brightest star is the yellow-white supergiant Alpha Persei (also called Mirfak), which shines at magnitude 1.79. It and many of the surrounding stars are members of an open cluster known as the Alpha Persei Cluster. The best-known star, however, is Algol (Beta Persei), linked with ominous legends because of its variability, which is noticeable to the naked eye.
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These jellyfish largely consisted of Nemopilema nomurai, Aurelia aurita and Cyanea nozaki, and the Institute of Oceanology, Chinese Academy of Sciences is undertaking research into how such blooms develop and their social and ecological effects. Reporting in 2014, the study found that the blooms were likely to be an indicator of worsening ecosystem health. They are linked to variations in sea temperature, increased pollution of coastal waters, overfishing, bottom trawling, and the depletion of oxygen levels due to algal blooms. These factors are favouring the survival of the polyp stage of the jellyfish life cycle and thus contributing to greater numbers of the jellyfish medusae.
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A swimming sea nettle known as the purple-striped jelly (Chrysaora colorata) Medusae swim by a form of jet propulsion: muscles, especially inside the rim of the bell, squeeze water out of the cavity inside the bell, and the springiness of the mesoglea powers the recovery stroke. Since the tissue layers are very thin, they provide too little power to swim against currents and just enough to control movement within currents. Hydras and some sea anemones can move slowly over rocks and sea or stream beds by various means: creeping like snails, crawling like inchworms, or by somersaulting. A few can swim clumsily by waggling their bases.
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Communication between nerve cells can occur by chemical synapses or gap junctions in hydrozoans, though gap junctions are not present in all groups. Cnidarians have many of the same neurotransmitters as many animals, including chemicals such as glutamate, GABA, and acetylcholine. This structure ensures that the musculature is excited rapidly and simultaneously, and can be directly stimulated from any point on the body, and it also is better able to recover after injury. Medusae and complex swimming colonies such as siphonophores and chondrophores sense tilt and acceleration by means of statocysts, chambers lined with hairs which detect the movements of internal mineral grains called statoliths.
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They found significant changes in the medusa population in two of these lakes, Clear Lake on Eil Malk and Goby Lake on Koror. The golden jellyfish population in Big Jellyfish Lake, Koror did not seem to be affected. The reason for this was not clear, but Big Jellyfish Lake experienced lower temperature increases than the other lakes and there was experimental evidence that the golden jellyfish medusa from Big Jellyfish Lake were more tolerant of higher temperatures. Although Clear Lake did not seem to have experienced the complete medusa population die-off that Jellyfish Lake did in 1998, the golden jellyfish medusae in Clear Lake are not always present.
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Alfred G. Mayer (Alfred Goldsborough Mayor; April 16, 1868 - June 24, 1922) was an American marine biologist and zoologist of German descent whose fascination with medusae (jellyfish) marked a turning point for biology. Despite Mayor's interest in the sea, his first voyage began during his twenty- fourth year of life. Because of his German 'heritage', "[...]he altered it (his last name) to "Mayor" in order to dissociate himself from his Germanic roots".Seafaring Scientist by Lester D. Stephens and Dale R. Calder: published in 2006 Mayor is also greatly known for his many publications and papers in which he wrote about topics ranging from physics to hunting and fishing.
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Cordylus macropholis, the large-scaled girdled lizard, is a small (55-77 mm) lizard endemic to the west coast of South Africa. They spend most of their time on and around a single plant species, Euphorbia caput-medusae which only occupies around 5% of the vegetation present. It is thought that they restrict themselves to these plants because they provide safer hiding places than most other shrubs, house a large range of invertebrate prey, and provide good thermal microhabitats. They can additionally be found sunbathing on, or hiding in between rocks, as these could provide protection from larger predators from which their physical adaptations might not provided them with adequate protection.
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Researchers reported that the largest single source of dust on Mars comes from the Medusae Fossae Formation. On 1 June 2018, NASA scientists detected signs of a dust storm (see image) on Mars which resulted in the end of the solar-powered Opportunity rover's mission since the dust blocked the sunlight (see image) needed to operate. By 12 June, the storm was the most extensive recorded at the surface of the planet, and spanned an area about the size of North America and Russia combined (about a quarter of the planet). By 13 June, Opportunity rover began experiencing serious communication problems due to the dust storm.
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The appearance of the plant fossil is a holdfast on the bottom, with a stem-like stipe between there and the fronds which are about to . In life, the fronds would have hung vertically whenever the plant was submerged during high tide, and would have flopped over the stipe when the plant was exposed during low tide in a habitus similar to that of the living sea palm. Other specimens from this deposit collected and described by Massalongo in 1855 were actually trace fossils, and they remain assigned to Zoophycos; only the specimens of Z. caput-medusae have been assigned to Postelsiopsis, as those are fossils of the original plant, and not trace fossils.
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Gertrude L. Van Wagenen was the daughter of Anthony Van Wagenen (1852–1937), a judge and lawyer in Sioux City, Iowa, and his wife Gertrude (née Louis). She completed undergraduate studies at Iowa State University in 1913, where she majored in zoology and was a member of the Beta Zeta chapter of the Kappa Kappa Gamma sorority. For a few years after graduating, she taught in Ottumwa, Iowa, and endured a case of scarlet fever, with the quarantine it required. In 1918, she collected corals, anemones, and medusae as part of the Barbados-Antigua Expedition, a group of University of Iowa graduate students and faculty studying the natural history of those islands.
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The two remained friends for life. Guided by Michael Foster, Romanes continued to work on the physiology of invertebrates at University College London under William Sharpey and Burdon-Sanderson. In 1879, at 31, Romanes was elected a Fellow of the Royal Society on the basis of his work on the nervous systems of medusae. However, Romanes' tendency to support his claims by anecdotal evidence rather than empirical tests prompted Lloyd Morgan's warning known as Morgan's Canon: :"In no case is an animal activity to be interpreted in terms of higher psychological processes, if it can be fairly interpreted in terms of processes which stand lower in the scale of psychological evolution and development".
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Virgin Shroud (1993), for example, is a veil made from a cow skin, with the udders forming a crown for the concealed figure; it references both the Virgin Mary and Meret Oppenheim's fur-lined teacup that was a partial inspiration for the piece. Saddle (also 1993) incorporates an upturned udder into the seat of a horse's saddle. Cross is perhaps best known for her public installation Ghost Ship (1998) in which a disused light ship was illuminated through use of luminous paint, in Scotman's Bay, off Dublin's Dún Laoghaire Harbour. A recent series, Medusae, includes images of Chironex fleckeri, a type of jellyfish and was made in collaboration with her brother Tom.
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Cnidaria are often studied to investigate their grazing rates in terms to smaller zooplankton because cnidarian’s are subject to large blooms. While they do consume a substantial amount of zooplankton when at peak abundance, due to the regeneration rate of copepidite stocks, N. bachei were not found to have a lasting effect on the overall population. They do display some amount of predatory behavior, in studies they have been shown to seek out new areas of prey when the rate at which they encounter prey starts to get decrease.Frost, J.R., Jacoby, C.A., Youngbluth, M.J. “Behavior of Nemopsis bachei L. Agassiz, 1849 medusae in the presence of physical gradients and biological thin layers”.
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Many of the numerous memoirs which he published, (including the very first paper he wrote) and which appeared in 1841, before he graduated, were on the structure of animals of the most varied kinds. Notable among these were his papers on the Medusae and allied creatures. His activity in this direction led him to make zoological excursions to the Mediterranean Sea and to the coasts of Scotland, as well as to undertake, conjointly with his friend Carl Theodor Ernst von Siebold, the editorship of the Zeitschrift für Wissenschaftliche Zoologie, which, founded in 1848, continued under his hands to be one of the most important zoological periodicals. His hand was one of the first to be x-rayed, by his friend Wilhelm Roentgen.
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Species of Aurelia can be found in the Atlantic Ocean, the Arctic Ocean and the Pacific Ocean, and are common to the waters off California, northern China, Japan, Korea, Australia, New Zealand, the Black Sea, Indonesia, the eastern coast of the United States as well as Europe. Aurelia undergoes alternation of generations, whereby the sexually- reproducing pelagic medusa stage is either male or female, and the benthic polyp stage reproduces asexually. Meanwhile, life cycle reversal, in which polyps are formed directly from juvenile and sexually mature medusae or their fragments, was also observed in Aurelia sp.1. The genus was first described in 1845 by Jean-Baptiste Lamarck in his book Histoire Naturelle des Animaux sans Vertebres (Natural History of Invertebrates).
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As seen on Viking and MOC imagery, the streamlined forms of the Athabasca Valles often have up to ten distinct layers exposed by later catastrophic erosion, with each layer having a thickness of up to 10m. They are often paralleled by grooves that are up to 10m tall, fading out from the streamlined forms within a few hundreds of meters. These grooves are interpreted to be depositional, and are dimensionally consistent with similar features observed within the Channeled Scablands of Washington State. In support of the megaflooding hypothesis, some authors have interpreted the platy and ridged terrains (described by others as characteristic lava textures) as relict sections of the underlying Medusae Fossae Formation that have been exhumed by aeolian processes.
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In the class Anthozoa, comprising the sea anemones and corals, the individual is always a polyp; in the class Hydrozoa, however, the individual may be either a polyp or a medusa, with most species undergoing a life cycle with both a polyp stage and a medusa stage. In class Scyphozoa, the medusa stage is dominant, and the polyp stage may or may not be present, depending on the family. In those scyphozoans that have the larval planula metamorphose into a polyp, the polyp, also called a "scyphistoma," grows until it develops a stack of plate-like medusae that pinch off and swim away in a process known as strobilation. Once strobilation is complete, the polyp may die, or regenerate itself to repeat the process again later.
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It is important to note that while the atmosphere of Mars is thinner, Mars also has a lower gravitational acceleration, so the size of particles that will remain in suspension cannot be estimated with atmospheric thickness alone. Electrostatic and van der Waals forces acting among fine particles introduce additional complexities to calculations. Rigorous modeling of all relevant variables suggests that 3 µm diameter particles can remain in suspension indefinitely at most wind speeds, while particles as large as 20 µm diameter can enter suspension from rest at surface wind turbulence as low as 2 ms−1 or remain in suspension at 0.8 ms−1. In July 2018, researchers reported that the largest single source of dust on the planet Mars comes from the Medusae Fossae Formation.
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The differing appearances of moon jellyfish is what has made them so hard to identify. They tend to have a variety of different sizes (9), however, they typically range from 5-38 centimetres in diameter with an average of 18 cm wide and 8 cm in height (10). The polyps of these jellyfish can grow to 1.6 centimeters tall and their ephyrae, the larval form of the jellyfish, have an average diameter of 0.4 centimetres (1). The adult medusae are typically translucent in color (1) but the color of their gut can change based on what they eat; for example, if they eat crustaceans, they can have a pink or lavender tint to them and if they were to eat brine shrimp, the tint would be more of an orange color (2).
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However, it is unclear how the other groups acquired the medusa stage, since Hydrozoa form medusae by budding from the side of the polyp while the other Medusozoa do so by splitting them off from the tip of the polyp. The traditional grouping of Scyphozoa included the Staurozoa, but morphology and molecular phylogenetics indicate that Staurozoa are more closely related to Cubozoa (box jellies) than to other "Scyphozoa". Similarities in the double body walls of Staurozoa and the extinct Conulariida suggest that they are closely related. The position of Anthozoa nearest the beginning of the cnidarian family tree also implies that Anthozoa are the cnidarians most closely related to Bilateria, and this is supported by the fact that Anthozoa and Bilateria share some genes that determine the main axes of the body.
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The medusae are either male or female. The young larval stage, a planula, has small ciliated cells and after swimming freely in the plankton for a day or more, settles on an appropriate substrate, where it changes into a special type of polyp called a "scyphistoma", which divides by strobilation into small ephyrae that swim off to grow up as medusae.Tree of Life - NJ Jellyfish - Aurelia aurita There is an increasing size from starting stage planula to ephyra, from less than 1 mm in the planula stage, up to about 1 cm in ephyra stage, and then to several cm in diameter in the medusa stage. A recent study has found that A. aurita are capable of lifecycle reversal where individuals grow younger instead of older, akin to the "immortal jellyfish" Turritopsis dohrnii.
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His scientific accomplishments included (in 1851) collaborating with Theodor Bilharz on the first description of the blood-fluke Schistosoma haematobium, (in 1853) the elucidation of the life cycle of the tapeworm Echinococcus granulosus, (in 1854) the suggestion that the cercariae of the fluke Fasciola hepatica were the infective stage which passed from the invertebrate to the vertebrate host, and (in 1856) the discovery of parthenogenesis in insects. He also published work on medusae, other cestodes and trematodes, and strepsipterans... His collection of worm specimens was purchased for the Helminth Collection of the Natural History Museum in London in 1851. His fish collection (1804-1855), specializing in freshwater fishes of Bavaria, was deposited at the Zoological Cabinet of the Bavarian State in 1863, and though most were lost in WWII, some specimens remain at the Zoologische Staatssammlung in Munich.
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Most jellyfish species have a relatively fixed life-span, which varies by species from hours to many months (long-lived mature jellyfish spawn every day or night; the time is also fairly fixed and species-specific). The medusa of Turritopsis dohrnii is the only form known to have developed the ability to return to a polyp state, by a specific transformation process that requires the presence of certain cell types (tissue from both the jellyfish bell surface and the circulatory canal system). Experiments have revealed that all stages of the medusae, from newly released to fully mature individuals, can transform back into polyps under the conditions of starvation, sudden temperature change, reduction of salinity and artificial damage of the bell with forceps or scissors. The transforming medusa is characterized first by deterioration of the bell, mesoglea, and tentacles.
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The publication of this beautifully engraved work was unfortunately delayed for nearly five years, owing to a dispute and a law process with the engraver, and the delay deprived Dalyell of the full credit of several of his discoveries in connection with medusae. The first volume of his last and great work, The Powers of the Creator displayed in the Creation, or Observations on Life amidst the various forms of the humbler Tribes of Animated Nature, was published in 1851. The second volume, after the author's death, was brought out in 1853, under the superintendence of his sister, Miss Elizabeth Dalyell, and Professor John Fleming, D.D., while the third volume was delayed until 1858. Dalyell became an enrolled member of the Highland and Agricultural Society of Scotland in 1807, and in 1817 was presented by his fellow members with a piece of plate for the invention of "a self-regulating calendar".
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