Jellyfish and ctenophores are carnivorous, and will eat just about anything they run into! Q. CUBOZOA are the box jellyfish, named for their box-like bells. Identification of Jellyfish and Jelly-like Animals, Cnidarian Facts: Corals, Jellyfish, Sea Anemones, and Hydrozoans, The Giant Siphonophore and More of the Largest Living Sea Creatures, Cephalopod Class: Species, Habitats, and Diets, Ph.D., Biomedical Sciences, University of Tennessee at Knoxville, B.A., Physics and Mathematics, Hastings College. Inside their mouths they have small cilia that act as teeth, pulling food apart, which also direct the food into the comb jelly's gut. Why are jellies becoming more common around the world? Crustacean Phromia uses prey's body parts to create a shell to live inside and feed young. Some species regenerate if injured and reproduce asexually as well as sexually. Eating jellyfish may become more common around the world as we overfish more preferable fish species. A beroid ctenophore lunges toward prey with its mouth wide open. Special cilia waving between the lobes generate a current to pull planktonic food between the lobes and into the jelly's mouth, allowing them to feed on plankton continuously. Comb Jelly. At night Cassiopea enters a sleep-like state where it pulses less frequently than during the day and is slow to respond to disturbances. Coelenterates can be found solitarily or in colonies. One jellyfish species is almost immortal. Sexes are separate in a few species, but most comb jellies are simultaneous hermaphrodites. Comb jellies lack microRNA and the molecular machinery to make them. Start studying Marine Bio Midterm. Too many jellies in the water can be a danger to swimmers, forcing towns to close their beaches. The Ctenophora body consists of two layers of cells called the ‘Epidermis’ and the ‘Gastrodermis’. Between them is a poorly defined third layer called the ‘Mesoglea’. (See The Stings: Nematocysts and Colloblasts for more. "Big red" is the nickname that MBARI marine biologists gave to this startlingly large jellyfish, (Marsh Youngbluth/MAR-ECO, Census of Marine Life). Plankton can be as small as algae or be longer than a blue whale. Once an item is stuck, the comb jelly reels in its tentacle and brings the food into its mouth. Jellyfish are cnidarians, while comb jellies belong to the phylum ctenophora. It reproduced and spread quickly, gobbling up zooplankton and leaving little behind for the larvae of commercial fish species, including anchovy, scad and sprat. They employ a wide range of strategies to catch prey. Between these layers is a gelatinous material called mesoglea, which makes up most of their bodies. After several days of development, the planulae attach to a firm surface and transform into flower-like polyps. They range in size and shape from tiny (0.04 inch) spheroids to long (4.9 feet) ribbons. Comb jellies, similar to jellyfish but they have a simpler life cycle and they lack nematocysts, so they capture prey with sticky cells on two long tentacles, moves around when combs of cilia beat in sequence. ), Jellyfish transition between two different body forms throughout their lives. The phylum Cnidaria also include the classes Hydrozoa, Anthozoa (corals and sea anemones), and Cubozoa (sea wasps and box jellies). They prey on other ctenophores and on zooplankton, including small crustaceans, fish larvae, and mollusk larvae. Additionally, some jellyfish have sensory structures called rhopalia, which contain receptors to detect light, chemicals and movement. Some species have tentacles. Beroids eat almost nothing but other Comb Jellies, which is pretty rude. But in 2007, a group of scientists including  Allen Collins from the Smithsonian National Museum of Natural History, discovered some beautifully-preserved jellyfish fossils buried in Utah from 505 million years ago. In 2011, Allen Collins, a jellyfish expert at the Smithsonian, discovered a new species, which was named Tamoya ohboya in a public naming contest. More information: A vanished history of skeletonization in Cambrian comb jellies, Science Advances 10 Jul 2015: Vol. CLIMATE CHANGE The ocean is warming, and this might give some jellies a boost. One species of ctenophore (Haeckelia rubra) recycles nematocysts from hydrozoan jellyfish it consumes and uses these to stun and kill prey. On the external surface of the comb jelly are eight rows of sets of cilia, these are called the ‘Costa’. Ocean sprawl provides more and better habitat for jellyfish to reproduce and complete their lifecycles. The comb jelly is a marine invertebrate that swims by beating rows of cilia that resemble combs. Some use tentacles to form web-like structures, others are ambush predators, and still others dangle sticky lures to attract prey. They are so named for their comb-like rows of beating cilia, which may appear brilliantly colored as they catch the light. Jellies have clogged up machinery at coastal power plants, causing power outages. (Listen to a podcast about box jellies.). This is the most basic nervous system known in a multicellular animal. These arguments continue because, as some of the simplest animals alive today, understanding their place in the tree of life helps people understand how all other animals—including people—evolved. Some cubozoans, such as the sea wasp (Chironex fleckeri), produce some of the most potent venom known. It’s much easier for jellyfish polyps to attach to man-made structures made of wood, brick and concrete than sand. The warmer water could help jelly embryos and larvae develop more quickly, allowing their populations to grow more quickly. Compared to jellyfish, there are far fewer species of ctenophores: only 100-150 species have been found, but quite a few are out there yet to be discovered and fully documented. Medusa jellyfish reproduce sexually by spawning—the mass release of eggs and sperm into the open ocean—with entire populations sometimes spawning all together. (… CYDIPPIDS all have rounded bodies—some spherical, some oval—with branched tentacles. Comb Jellies belong to a separate category just for them called “Ctenophora.” This means that even though Comb Jellies are transparent (like Jellyfish), the combs that reflect light and help the jelly to swim put Comb Jellies in a world of their own! After a segment separates from the strobila, it is called an ephyra, a juvenile jellyfish. Another difference between jellyfish and comb jellies is that jellies tend to move with their mouths trailing, combs forage and move with the mouths forward. True to the Darwinist habit of Tontologism, Michael Marshall says “we” have figured this out. Their body is acoelomate and triploblastic, with the outer epidermis, inner gastrodermis, middle jelly-like mesoglea with scattered cells, and muscle fibers. Comb jellies produce gametes as long as there is sufficient food. Comb Jellies belong to a separate category just for them called “Ctenophora.” This means that even though Comb Jellies are transparent (like Jellyfish), the combs that reflect light and help the jelly to swim put Comb Jellies in a world of their own! While commonly confused with the jellyfish and other Cnidaria, the comb jellies belong to their own distinct phylum, the Ctenophora, believed to be one of the planet's oldest and most basal forms of animal life. Why? To this day, some researchers believe they are sister groups, while others think they are not closely related. Young jellyfish are small enough to be part of the general zooplankton population and are eaten by many animals. Contrary to popular belief, Comb Jellies are not even Jellyfish at all! When kept awake throughout the night, the next day the jellyfish appear to be tired—their pulsing was noticeably slower than if they had a solid night of sleep. Most animals can't survive in these conditions, but many jellies can better tolerate low-oxygen environments. Comb jellies are not found in fresh water. That makes jellyfish three-times as old as the first dinosaurs! To distinguish them, all Cnidaria and Ctenophora were once described as Coelenterata—but that term is no longer commonly used. To what does the phras comb jelly" refer? However, the collapse of a fishery doesn't always end in jellyfish. What trait gives jellies in the Phylum Ctenophora their common name? As seawater temperature rises, predators of jellies are removed by fishing, more structures are built in seawater, and more nutrients flow into the ocean, some types of jellyfish and comb jellies may be finding it easier to grow and survive. Whatever the reason, huge explosions in jelly numbers (a jelly bloom) can disrupt fisheries, make for unpleasant swimming, or foul up the works of power plants that use seawater for cooling. The best-known comb jellies are those found close to shore because, there, they are most likely to run into people. The polyp, the other cnidarian body plan, is the opposite, with the mouth and tentacles above, like a sea anemone. Gametes are expelled through the mouth. Some are shaped like belts (Cestida), while others don't float in the water column at all, but live on the seafloor! 1, no. Ctenophores are the largest non-colonial animals that use cilia for locomotion. 2. To undergo their polyp stage, jellyfish need solid surfaces to settle upon. This discovery adds another piece to the evolutionary puzzle of when animals evolved to have anuses. (See Brains of Jelly? (New York Times Magazine)14 Fun Facts About Jellyfish (Smithsonian Magazine), Many jellyfish in the class Hydrozoa, such as this hydromedusa, (K. Raskoff, Monterey Peninsula College, Hidden Ocean 2005, NOAA), (K. Raskoff, Monterey Peninsula College, Hidden Ocean 2005, NOAA.). This is not bioluminescence, but occurs when light is scattered in different directions by the moving cilia. (NOAA/OAR/National Undersea Research Program (NURP)), A transparent body helps this tiny comb jelly (. Guided by this sensor, eight “combs” work together to propel the creature through the water. 1. In the water column, the colonial siphonophores may be quite spectacular. lot like them, comb jellies are not jellyfish, instead they belong to the phylum Ctenophora. Many jellyfish and comb jellies are able to produce light—an ability known as bioluminescence. (Although some small species have very thin mesoglea.) Jellyfish are cnidarians, while comb jellies belong to the phylum ctenophora. Mar 25, 2014 - Explore Nicholas Capitini's board "Phylum Ctenophora" on Pinterest. A small number of jellyfish are very toxic to humans, such as the box jellyfish (Chironex fleckeri) and Irukandji jellyfish (Carukia barnesi), which can cause severe reactions and even death in some people. Contrary to popular belief, Comb Jellies are not even Jellyfish at all! It is the first time an animal without a brain was observed sleeping. Ctenophora (/ t ɪ ˈ n ɒ f ər ə /; singular ctenophore, / ˈ t ɛ n ə f ɔːr / or / ˈ t iː n ə f ɔːr /; from Ancient Greek: κτείς, romanized: kteis, lit. Those can be roughly divided into three groups. This method may not seem very efficient, since it's likely that most of the gametes never find a match. Comb Jelly. Comb jellies have rainbow cilia that illuminate them. In most species, fertilization takes place in the water; in others, the sperm swim up into the female's mouth and fertilize the eggs within. Like other marine species, they are affected by climate change, pollution, and weather. These include the notorious Portuguese Man-o-Wars and many deep-sea forms, some of which stretch out up to 50 meters in length like giant fishing nets. SUBMARINE SPRAWL Many industries, such as shipping, drilling and aquaculture, build docks, oil platforms and other structures in the water—sometimes referred to as “ocean sprawl"—which can serve as nurseries for jellyfish. They are trumpet-shaped, and mostly live in cold water. A new study showed that comb jellies in fact release indigestible particles through pores on the rear end of the animal. Yet even as these researchers examined the “simple” comb jellies, they were baffled by their complexity. They are basically a sack with a gigantic mouth at one end and, unlike other Comb Jellies, they have no tentacles for capturing prey. Play this game to review Zoology. A crash in the pollock and walleye fishery in the Bering Sea left an opening for jellyfish but, after reigning for a few years, the jellies gave up their crown as the fish returned. 6, e1500092.DOI: 10.1126/sciadv.1500092. Stung! All cnidarians possess stinging cells called nematocysts. Little is known about most species, but the lifespan of those that have been studied ranges from less than a month to three years. HYDROZOA are jellyfish look-alikes but not in the same group as the “true jellyfish.” The swimming medusa stages of this group are often small and inconspicuous, whereas the bottom-dwelling polyps, or hydroids, usually take the form of large colonies. Once eggs and sperm find each other, the embryo develops into a larva that looks just like a small adult ctenophore—and, from there, all it has to do is grow up. Some are lobe-shaped, while bottom-dwelling species resemble sea slugs. An adult jellyfish is called a medusa, which is the familiar umbrella-shaped form that we see in the water. Some jellyfish sit upside down on the bottom and have symbiotic algae (zooxanthellae) in their tissues, which photosynthesize, and so get much of their energy the way plants do. They also have short tentacles and tend to grow larger than cydippids. The Venus' girdle is a ribbon-like comb jelly. Scientists hope to address this problem through the discovery of a practical application for jellyfish, like substituting jellyfish for the fish used in aquaculture feed. The outer cells that make up the epidermis contain a loose network of nerves called the "nerve net." Some species control zooplankton which could wipe out phytoplankton if left unchecked. It also contains some structural proteins, muscle cells, and nerve cells, forming a kind of internal skeleton. Most species are bioluminescent blue or green and some flash light or eject a bioluminescent "ink" when disturbed. Chemoreceptive cells near the jelly's mouth allow it to "taste" prey. New Scientist chooses the comb jellies, or ctenophores. Throughout their lifecycle, jellyfish take on two different body forms: medusa and polyps. Why would they be red instead of black to blend in with the dark water? Jellyfish and ctenophores both have tentacles with specialized cells to capture prey: nematocysts and colloblasts, respectively. Comb jellies, on the other hand, belong to the phylum Ctenophora. Jellyfish and comb jellies are 95 percent water and so, rightly, mesoglea is mostly water! A similar story of fishery collapse coinciding with jellyfish blooms is playing out off the coast of Japan. The discovery suggests sleep among all animals is an ancient characteristic with a shared evolutionary beginning, considering the neural network of jellyfish evolved before centralized nervous systems like a brain. The rounded and tentacled cydippids have branched tentacles lined with colloblasts that they use, in the traditional jelly style, like a fishing line to trap food and bring it to their mouths. One species (Mertensia ovum) can reproduce even when it is still larva, and scientists think other species are also able to reproduce at a young age. The debate has gone back and forth for decades now. Both groups are ancient animals, having roamed the seas for at least 500 million years. Colonial siphonophores are composed of many specialized individuals called zooids that are genetically identical because they all come from a single fertilized egg. Approximately 150 comb jelly species have been named and described to date. Habitat: ADVERTISEMENTS: All ctenophores are exclusively marine. whole and then clamp their mouths shut, giving them no escape route. The cell is activated upon touch or chemical cue, causing the harpoon to shoot out of the cell and spear the prey or enemy, releasing toxin—a process that takes only 700 nanoseconds. The combs act like tiny oars, propelling the comb jelly through the water. Hence name as comb jellies. As these other predators of plankton are fished from the sea, jellies have less competition for food, and are able to grow and reproduce with fewer limits. (New York Times Magazine), 14 Fun Facts About Jellyfish (Smithsonian Magazine). One group of jellyfish, the cubozoan jellyfish, have complex eyes with lenses, corneas and retinas in their rhopalia. These beat continuously, propelling the jelly through the water. In comparison to the jellyfish, comb jellies have a very simple lifecycle. In schyphozoans, a process called strobilation takes place (shown in video and in diagram). They tend to be very fragile because they don't have to endure rough coastal waves; many of them are so fragile that they cannot be collected by submersibles and are known only by photographs. During strobilation, a polyp splits into 10-15 plate-like segments stacked atop one another in a tower called a strobila. They're also the first animals known to swim using muscles instead of drifting with the whims of the waves. Jellyfish have a complex life cycle: a single jellyfish reproduces both sexually and asexually during its lifetime, and takes on two different body forms. A few species are also found in freshwater habitats. There is no coelom. Here’s a shocker! Habits: They feed on plankton, swim by cilia. Invasive jellies have also wreaked havoc in some parts of the world. Jellies are found in oceans worldwide, in shallow and deep water, and a few can even be found living in freshwater. Comb Jellies belong to a separate category just for them called “Ctenophora.” This means that even though Comb Jellies are transparent (like Jellyfish), the combs that reflect light and help the jelly to swim put Comb Jellies in a world of their own! The comb rows scatter light and produce a rainbow effect. Nervous impulses direct muscles to move the animal as well as to capture and manipulate prey. Those 4,000 jellyfish can be divided into four different groups. A 2017 study of the upside-down jellyfish, Cassiopea, found that a brain is not required to experience sleep. More than half the known species of Comb Jellies are part of the class Nuda. In the 1980s, the sea walnut (Mnemiopsis leidyi), a type of comb jelly, was brought to the Black Sea in ship ballast water. The animals of Radiata belong to one of two phyla: Cnidaria or Ctenophora. Many microscopic organisms, such as bacteria, also use cilia to swim—but comb jellies are the largest known animals to do so. Jellyfish and comb jellies vary greatly in size depending on the species. Diploblastic or … Along their body run eight ciliated bands (rows of combs) which are their main mean of locomotion as well as the main reason for their … In 1982, it was discovered in the Black Sea, where it was transported in, (Marco Faasse, World Register of Marine Species), tentacles can be withdrawn into the jelly's body, Eating jellyfish may become more common around the world, recycles nematocysts from hydrozoan jellyfish, swallow their prey (often other ctenophores!) Open ocean ctenophores are much less known. Scientists are optimistic this discovery will help tease out the relationship between jellyfish and comb jellies. There are around 3,700 species of Hydrozoa. Contrary to popular belief, Comb Jellies are not even Jellyfish at all! Some 425,000 tons (more than 900 million pounds) of jellyfish are caught each year by fisheries in 15 countries, and most are consumed in Southeast Asia. Comb jellies belong to an entirely separate phylum, Ctenophora. These tentacles can be withdrawn into the jelly's body into special sheaths or pouches on either side of their mouths. They are both beautiful—the jellyfish with their pulsating bells and long, trailing tentacles, and the comb jellies with their paddling combs generating rainbow-like colors. (See more in Reproduction & Lifecycle. Generally, comb jellies are not considered threatened or endangered. Comb jellies are the largest creatures that use cilia to aid movement. They are armed with sticky cells (colloblasts) and unlike jellyfish, the tentacles of comb jellies don’t sting. The polyps have a mouth and tentacles that are used to feed on zooplankton. There are around 50 staurozoan species, many notable for their unique combination of beauty and camouflage. Ephyrae mature into the medusa form. Ctenophores were until recently thought to be most closely related to the Sea anemones and corals belong to the phylum What is unique with regard to the cnidarians? Jellies are very good at surviving: they have broad diets, reproduce quickly, can shrink down if food runs out and then revive, and tolerate low-oxygen water. COMB JELLIES: Have soft, transparent, sack-shaped bodies constructed with external and internal surfaces holding in a middle layer of gelatinous tissue. Jellyfish belong to the class Scyphozoa within the larger phylum Cnidaria. (These are known as benthic ctenophores.). Turritopsis nutricula, a small hydrozoan, can revert back to the polyp stage after reaching adult medusa stage through a process called transdifferentiation. Monterey Bay Aquarium JelliesComb Jellies in the Chesapeake BayCnidaria on the Tree of LifeHydromedusae, Stauromedusae, and Ctenophores, Books Comb jellies come in many shapes and sizes, and so within the group there are many ways to feed. (Mary Elizabeth Miller, Dauphin Island Sea Lab), Stinging cells (nematocysts) line the tentacles of this moon jelly (. Jellyfish and comb jellies are in different phyla, but scientists have long argued over whether they have an especially close relationship apart from the rest of the animal kingdom. The nerve net has some specialized structures such as statocysts, which are balance sensors that help jellies know whether they are facing up or down, and light-sensing organs called ocelli, which can sense the presence and absence of light. The familiar body plan that looks like an upside down bell with tentacles hanging down from the inside is called the medusa. Upon touch, a spiral filament automatically bursts out of colloblast cells that releases the sticky glue. Most are nearly colorless and transparent, so they can be difficult for predators to see. Most species are hermaphroditic and able to release both eggs and sperm into the water, which drift with the waves until they find other gametes. Examples include the sea gooseberry (Pleurobrachia sp.) Yet though they look similar in some ways, jellyfish and comb jellies are not very close relatives (being in different phyla—Cnidaria and Ctenophora, respectively) and have very different life histories. A lot of these marine species, including fish and invertebrates such as squid, eat some of the same food that jellies do: mainly, zooplankton. Although they respond to visual stimuli, scientists don’t know how the jellyfish interpret the images created by their eyes since they don’t have a brain with which to process them. The oldest ancestors of modern day jellies lived at least 500 million years ago, and maybe as long as 700 million years ago. Medusa or adult jellyfish typically live for a few months, depending on the species, although some species can live for 2-3 years in captivity. Comb jellies are superficially similar to jellyfish and, like them, are to be found floating in the sea. However, some deep sea jellyfish and comb jellies are a bright red or orange color. In contrast to jellyfish, comb jellies are not radially symmetrical. Let’s take a look at some Illuminating facts about Comb Jellies: They come in a great diversity of forms. No, comb jellies were first! (See The Stings: Nematocysts and Colloblasts for more.). Contrary to popular belief, Comb Jellies are not even Jellyfish at all! And, in the modern age, they are having similar effects on ecosystems. If they run out of food while producing so many eggs and sperm, they can shrink and hunker down until they run into more food and can start reproducing again. Dr. Helmenstine holds a Ph.D. in biomedical sciences and is a science writer, educator, and consultant. The name ctenophora comes from Greek words that mean "comb carrying." Both have two major cell layers: the external epidermis and the internal gastrodermis. Coelenterates can be called as the simplest animal group that has true tissuesand have the characteristic coelenteron or the gastrovascular cavity. Thus, the correct answer is option D. Species that live near the water surface are transparent, but those that live deeper in the water or parasitize other animals may be brightly colored. This means that comb jelly populations can grow very fast under certain conditions. Comb jellies are prey for several species, including the endangered leatherback sea turtle. Instead of catching food with colloblasts, they swallow their prey (often other ctenophores!) She has taught science courses at the high school, college, and graduate levels. Around the world, vast aggregations of jellyfish and comb jellies seem to be more common. Some argue that a new fossil from the Chengjiang fossil site in China and a peculiar fossil in the Burgess Shale are similar enough to jellyfish that they might be ancient comb jellies that had recently split from the jellyfish lineage. and Venus' girdle (Cestum veneris). Ctenophores use different neurotransmitters than other animals. The fertilized eggs then develop into planulae (singular: planula), which are ciliated free-swimming larvae shaped a bit like a miniature flattened pear. You can find them sedentary or free swimming. In 2016, researchers discovered what they believe to be a new hydrozoan species of Crossota, 12,140 feet (3,700 meters) deep within the Mariana Trench. Within a decade, the comb jellies took over the Black Sea and many of the fish populations collapsed, bringing local fisheries down with them. If the blooms are human-caused, there are several probable culprits. There are more than 10,000 species of Cnidaria, and less than 4,000 of these are Medusazoa—those animals we think of as jellyfish. Because they don't need them of course! Comb Jellies belong to a separate category just for them called “Ctenophora.” This means that even though Comb Jellies are transparent (like Jellyfish), the combs that reflect light and help the jelly to swim put Comb Jellies in a world of their own! The combs act like tiny oars, propelling the comb jelly through the water. Comb jellies (Ctenophora) belong to a verge of invertebrates that inhabit marine waters around the world. The comb-rows often produce a rainbow effect. Spineless: The Science of Jellyfish and the Art of Growing a Backbone by Juli Berwald The comb jelly directs its movement through a network of nerve and muscle cells, draped symmetrically around a gravity sensor. But ctenophores make up for this by releasing them every day. SCYPHOZOA are the most familiar jellyfish, including most of the bigger and more colorful jellies that interact with humans, and are sometimes called "true jellyfish" for this reason. Their nerve ring, a ring-shaped concentration of nerves found in jellyfish, seems to be involved, however. for more.). Comb jellies are named for their unique feature: plates of giant fused cilia, known as combs, which run in eight rows up and down their bodies. BEROIDS (also known as "nuda") are sack-shaped and have no tentacles at all—but they do have a very large mouth, which they can zip shut very tightly. STAUROZOA are the stalked jellyfishes, which don't float through the water like other jellies, but rather live attached to rocks or seaweed. Most jellies primarily eat plankton, tiny organisms that drift along in the water, although larger ones may also eat crustaceans, fish and even other jellyfish and comb jellies. Either way, there are still plenty of other questions to argue about, such as how long ago the two groups diverged, and even whether ctenophores might be the most ancient group of animals, diverging even earlier than sponges in the animal tree of life. While their nematocysts and colloblasts do help them defend themselves, plenty of animals manage to catch and eat jellies: more than 150 animal species are known to eat jellies, including fish, sea turtles, crustaceans, and even other jellyfish. No ctenophore species has a conservation status. Both self-fertilization and cross-fertilization can occur. Some even engage in elaborate (for a jellyfish) courtship behavior! Humans also eat jellyfish: people have fished for jellies for at least 1700 years off the coast of China. Jellyfish mucus, which has been shown to bind to microplastics, may even one day be used in water treatment facilities to help combat the world’s growing plastic problem. Ethan Daniels/Stocktrek Images / Getty Images. whole, Can a Jellyfish Unlock the Secret to Immortality? A cameraman navigates a smack of sea nettles (, This ctenophore is native to the east coast of North and South America. Jellyfish: A Natural History by Lisa-ann Gershwin All jellyfish are Cnidaria, an animal phylum that contains jellies, sea anemones, and corals, among others. comb jellies are approximately 1.5 cm long and egg-shaped, with one mouth on one end and anal pores on the other one ( aboral end). Them, are to be more common around the same period, have... Have rounded bodies and tentacles that are genetically identical because they all come from a single egg. Ctenophores both have tentacles with specialized cells to capture prey: nematocysts and for... Eggs and sperm to reproduce sexually are the ctenophores that belong to the jellyfish, but comb jellies or..., rightly, mesoglea is mostly water they can self-fertilize as well as sexually glue... 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