Coelenterate interesting facts. Report on coelenterates Arctic giant jellyfish Cyanea

The only coelenterate animals in their group have stinging capsules, thanks to which they, if necessary, usually during irritation, throw the thread out of the body; it contains poison. It should paralyze any attacking animal, but this applies mainly to small individuals.

Coelenterates have tentacles, which are considered important parts of their body. The tentacles serve as hands, with the help of which the animal grabs prey and pushes it into its mouth, where the prey is partially digested, digested into small fragments, then the food passes to the ecdothermal cells, which already absorb useful substances. Undigested particles are removed again through the oral cavity.

The hollow threads of coelenterates, with which animals defend themselves and neutralize other animals, look like tentacles. At their tips there are stinging cells; in appearance they look like harpoons that dig into the body of the victim and release poison.

In some coelenterates, the poison of the stinging cells can even act on humans. It is believed that the venom of coelenterate animals is not harmful to humans, but this big mistake. Some species of these animals cause serious burns to humans. There are known cases when the nervous or respiratory system and people died a painful death.

In coelenterate animals, there are two categories: those that lead an active lifestyle and those that do not lead a mobile lifestyle. In general, people should avoid any encounters with these animals so as not to put their health at risk. For example, sea anemones are more like flowers; these animals have many tentacles that search for prey.

Wow!.. That's it!.. Be healthy!..

• Type: Cnidaria (Coelenterata) Hatschek, 1888 = Coelenterates, cnidarians
• Subphylum: Anthozoa Ehrenberg, 1834 = Corals, coral polyps, non-jellyfish
• Class: Hexacorallia = Six-rayed corals
• Class: Octocorallia Haeckel, 1866 = Eight-rayed corals
• Subphylum: Medusozoa = Jellyfish-producing
• Class: Cubozoa = Box jellyfish
• Class: Siphonophora = Siphonophora
• Class: Scyphozoa Götte, 1887 = Scyphozoa
• Class: Hydrozoa Owen, 1843 = Hydrozoa, hydroids (Hydra)

Type: Cnidaria (Coelenterata) Hatschek, 1888 = Coelenterates, cnidarians

The world of coelenterates are amazing living creatures with a complex body structure and well-controlled behavior. Although, the jellyfish, consisting of 98% water and in appearance, is one of the simplest life forms

, but in fact it is capable of exhibiting complex nutritional, protective and many other reactions.

Coelenterates have organs of vision and balance, and are able to respond to environmental factors such as light, heat, mechanical, chemical and other influences. In this case, for example, in sea anemones, each part of the body is characterized by a reaction to a certain type of external influence. With her mouth she perceives chemical irritation without feeling mechanical impact, to which, however, the sole is sensitive. And the body walls and tentacles of the sea anemone respond to mechanical, chemical, and electrical influences. Thanks to a variety of devices and living “instruments”, these living beings are able to respond to these external signals with an adequate response and carry out purposeful movements. Let's look at some examples.

"Device" for predicting storms The jellyfish is known for its ability to sense the approach of a storm in advance using a device to detect infrasounds. These acoustic shocks with a frequency of 8-13 hertz are created by the pre-storm wind when the water slams on the crest of a wave. In humans, such infrasounds cause nervous tension . And they signal to the jellyfish’s body twenty hours before the storm begins that it is approaching. Thanks not only to the so-called “infraear”, but also to the signal recognition system, the jellyfish leaves in time danger zone

. Otherwise, its gelatinous body may be broken by storm waves on rocks or washed ashore.

The structure of the living “device” of the jellyfish interested bionics. Its bell-shaped body is equipped with eyes, organs of balance, as well as auditory cones the size of a pinhead - the “ear” of the jellyfish. Its bell, like a megaphone, amplifies the infrasound that occurs before bad weather. Then it is transmitted to the auditory cones of the jellyfish, and she hears the echoes of a storm located hundreds of kilometers away. Based on the principle of operation of such a magnificent device as the “infraear” of a jellyfish, bionics have created an automatic device - a storm predictor. It allows you to avoid many of the terrible consequences of a storm, because... warns about it 15 hours in advance, and a traditional barometer only two hours in advance.

The life activity of many living beings is cyclical and is triggered by certain key stimuli. One of the most important cycles is the alternation of day and night. Other cycles are associated with the changing seasons, ebbs and flows. Moreover, this is not only a direct reaction to change external conditions. Such biological rhythms also occur in artificial conditions due to the presence of internal “biological clocks” in living organisms. They involve the most complex multifunctional structures and mechanisms: systems for analyzing the situation in the external and internal environment of the body; mechanisms of inclusion of certain nervous and other components; regulators of periodically manifested behavioral acts and much more.

Scientists still do not know where such “clocks” are located, with which organs, elements of the cell and organism they are connected, what is the nature of the processes occurring in them, what underlies their “course” - physical or chemical changes. And, despite the complexity of such systems, the “primitive” organism of the coelenterates has a very accurate biological “clock”. Thus, sea anemone equina is able to determine the time of high and low tide with an accuracy of several minutes. Experiments in the aquarium made it possible to establish that the sea anemone blooms during high tide, opening its tentacles, and contracts them at low tide not only natural conditions. She retains this ability in a special aquarium. This rhythm in an artificial environment is very stable and persists for several days after the start of the experiment.

Ability to carry out coordinated movements

Some representatives of the coelenterates are sedentary attached animals. Others can change body shape and move thanks to coordination systems that allow targeted contractions and relaxations of specific muscle cells.

Coelenterates, or radials, are a group of multicellular invertebrate animals.
Coelenterates are the only animals in their group that have stinging capsules, thanks to which they can, if necessary, usually during irritation, throw out a thread that contains poison from their body. The poison should paralyze any attacking animal, but this usually only affects small animals.

Interesting facts about coelenterates

- Coelenterates have tentacles, which are important parts of their body. With the help of tentacles, the animal grabs its prey and pushes it into its mouth, where partial digestion takes place, the prey is digested into small fragments, then they pass to the ectodermal cells, they already absorb useful substances. If some particles are not digested, they come back out through the oral cavity;

- hollow threads with which coelenterates protect themselves and neutralize other animals look like tentacles. The stinging cells are located at the tips of the tentacles, along appearance they are similar to harpoons that dig into the body of the victim and inject poison;

— the poison of the stinging cells of some coelenterate animals even affects humans. It is believed that the poison from various coelenterates is not harmful to humans, but in fact this is a misconception. Some animal species can cause severe burns in humans; cases of respiratory and respiratory failure have also been recorded. nervous system, which led to painful death;

- Coelenterate animals are divided into two categories, one of them leads an active lifestyle, and the other leads a stationary lifestyle. In general, people should be wary of all varieties of these animals to avoid putting their health at risk. For example, sea anemones look more like flowers, but in fact they are animals with many tentacles that are just looking for prey;

— jet engines were created thanks to observation of jellyfish, which move like them.

- most representatives reproduce sexually and have planktonic or crawling larvae. The life cycle of a significant part of cnidarians is metagenesis: a natural alternation of sexual and asexual reproduction.

— Humans use some coelenterates. The dead calcareous parts of corals are extracted from construction material, when roasted, lime is obtained. Black and red corals are used to make jewelry.

Some coelenterates can cause burns to divers, swimmers and fishermen with their stinging cells. In some places, coral reefs prevent the passage of ships, while providing shelter and food for fish.

— Since they are coelenterate predators, they influence marine animal communities, they eat plankton, and large sea anemones and jellyfish also eat small fish. In turn, they feed on jellyfish sea ​​turtles and some fish. Some types of jellyfish are edible ( Rhopilema esculenta, Rhopilema verrucosa)

Description of the presentation by individual slides:

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Amazing coelenterate animals Performed by Olga Vasilievna Smolkovskaya, teacher of gymnasium No. 73 “Lomonosov Gymnasium”

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a brief description of coelenterates Live in aquatic environment(mainly in the seas and oceans) The body is sac-like, formed by two layers of cells: the outer - ectoderm, and the inner - endoderm, between which there is a structureless substance - mesoglea. Inside there is a cavity with a mouth. The symmetry of the body is radial. Two life forms are characteristic: a sessile polyp, and a floating - jellyfish, they can alternate in life cycle of the same species, but some groups do not have a medusoid generation or have lost the life form of a polyp. Most species are solitary, but there are also colonial forms, all predators. Characterized by the presence of stinging cells that contain a capsule with a poisonous liquid; Inside the capsule there is a stinging thread in the form of a spiral, and on the surface there is a sensitive hair. When irritated, the stinging thread is thrown out. The function of these cells is defense and attack. Very ancient animals

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Systematics About 9 thousand species are known, classes are divided into Class Hydroids 2800 species Class Scyphoid jellyfish 200 species Class Coral polyps 6000 species

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The largest coelenterate animal Arctic giant jellyfish Cyanea lives in the northwestern part of the Atlantic Ocean, so one such jellyfish, which was washed ashore in Massachusetts Bay, had a bell diameter of 2.28 m and tentacles 36.5 m long. This is the longest animal on Earth; during its life, such a jellyfish eats approximately 15 thousand fish. This jellyfish is not dangerous to humans, but the rashes and allergic reactions are unpleasant. Arctic cyanea

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Biggest coral reef Big barrier reef– the world's largest coral reef, one of seven natural wonders light, it can be seen from space. Stretched along the north - east coast Australia at 2500 km. The range contains more than 2,500 individual coral reefs and 900 islands in the Coral Sea. The reef structure is made up of billions of tiny organisms - coral polyps, usually during the day the corals shrink, and at night they spread their tentacles, with the help of which they catch small animals. There is no jellyfish stage; individual polyps resemble a hydra, but are more complex. Reproduction: sexual and asexual way(budding) After death, the polyp leaves its calcareous skeleton, many skeletons form a coral reef. Reef inhabitants - 400 species of corals (various colors), 1500 species tropical fish, a huge number of other organisms.

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Corals Coral is the skeletal material of a colony of coral polyps. Over 3,500 species of corals are known, with up to 350 shades. The “growth” of corals in favorable conditions is no more than 1 cm per year, the average reef takes centuries to form, and an island takes millennia. Composition of corals: calcium carbonate, admixtures of magnesium carbonate and a small amount of iron oxide, about one percent organic matter. Indian black coral is composed almost entirely of organic matter. Corals are used for lime, some for making jewelry. Black (“Akkabar”), white and silver-pearl (“angel skin”) are prized. The most popular red noble coral, iron oxide, gives it different shades of red, it lives in the Mediterranean Sea, near Canary Islands at a depth of more than 20 meters. Black coral is mined in China and India. The cost of natural corals is high, so there are many fakes. In Egypt and Thailand, the export of corals is prohibited by law; in Egypt, a fine of $1,000 is imposed for this. Red and black corals and jewelry made from them

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The smallest coelenterates Some of the smallest coelenterates are polyps on colonies of hydroids; their size barely reaches 1 mm. This is a complex of individuals sitting, as it were, on a common trunk and its side branches, they look like a tree, a bush, on the branches there are individual individuals of the colony - hydroids, each individual resembles a hydra. They attach to the rocky bottom or to various underwater objects, usually grow quickly; a bush 5-7 cm high can grow in a month.

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The smallest jellyfish are Jellyfish of the Irukandji group (named after the Australian Irukandji tribe), their size is 1.2 - 2.5 cm in diameter. Milky white in color, they have four thin tentacles ranging from a few millimeters to 1 meter in length. Very poisonous, their venom has multiple paralytic effects - Irukandji syndrome, can lead to fatal outcome for a person. Most often found off the coast of Australia. Jellyfish are more accurate than a barometer Strong wind over the sea, it removes not only spray and foam from the crests, but also infrasounds. They quickly run in all directions and warn all the inhabitants of the sea who hear them about the approaching storm. And the jellyfish hears it: sound infrawaves with a frequency of 8 - 13 hertz hit tiny pebbles that float in the “ear” of the jellyfish - a tiny ball on a thin stalk. The pebbles rub against the nerve receptors in the walls of the “ball”, and the jellyfish hears the roar of the approaching storm, sinks to the bottom so as not to die. The “jellyfish ear” device has already been designed. The device works with great accuracy: it warns about the approach of a storm 15 hours in advance (1965) Irukandji jellyfish - Carukia barnesi

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Edible jellyfish There are approximately 12 species of edible jellyfish in the world. The most expensive and delicious ropilema is edible, the diameter of the umbrella is 50-60 cm, and it is not dangerous for humans (it burns like a nettle). Lives in the Pacific and Atlantic oceans. The aurelia jellyfish is also edible, the most delicious is the eared aurelia (it was so named because of the 4 blades that hang from under the dome like hare ears), lives in the Pacific, Indian, Atlantic Ocean, umbrella diameter 5-40cm. It is not dangerous for humans after contact with it, a slight burning sensation is felt. Only females are used since there are few males. The Chinese call jellyfish food “crystal meat”, its main quality is crunchiness, and the head crunches the most; in China only wealthy people eat it. Jellyfish is a delicacy among the Chinese, Japanese, and Koreans. Ropilema edible Aurelia eared

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A jellyfish that throws off tentacles. Colobonema (Colobonema sericeum) - this jellyfish throws off tentacles, and it has 32 of them, the same thing happens to a lizard when it is grabbed by the tail. These jellyfish live at a depth of 500–1500 meters and rarely have a full set of tentacles. Colobonema in its entirety can be seen only on the surface of the ocean. This is a small jellyfish, the diameter of its dome is approximately 5 cm. Sessile jellyfish. Staurojellyfish, a group of sessile jellyfish, are radically different in structure from free-swimming species. About 30 species are known, 12 species live in Russian seas. The body is like a bowl on a long leg (the leg is attached to the ground or algae). At the end of each “arm” there is a bunch of short tentacles similar to a dandelion. The sizes are usually 1-3cm, and lucenaria up to 15cm. If necessary, they can move as if turning over, taking several steps per day. Their behavior and movement are reminiscent of hydra, predators. Benthic sessile jellyfish Cassiopeia Sessile jellyfish Lucenaria Colobonema

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The most dangerous coelenterate animal poisonous jellyfish in the world - Australian sea ​​wasp(Chironex fleckeri) Dome length about 12 cm, almost invisible in water. Lives off the coast of Australia, the Pacific coast and Indian Ocean. After touching its tentacles, a person dies in 1-3 minutes, if not medical care, the poison paralyzes the heart muscle, just touching its tentacles, the supply of poison in its stinging cells is enough to kill 250 people. The protective equipment is women's tights, which were used by lifeguards at surfing competitions in Queensland, Australia.

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Poisonous coelenterates Far Eastern cross jellyfish (Gonionemus vertens) Named for the pattern on the dome in the form of a cross. The diameter of its dome is 2-3 cm, rarely 4 cm, has 50 - 80 tentacles, feeds small crustaceans near the shore overgrown with vegetation. After 10 min. after its “burn,” a person experiences general weakness, pain in the lower back and joints, breathing becomes difficult, arms and legs go numb, and there is a danger of drowning. The acute period lasts 4-5 days, then these phenomena decline and disappear without consequences.

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Poisonous coelenterates False fire corals (Millepora) - are not classified as corals - they are hydroid polyps, live in the Red and Caribbean Seas, settle among real corals, up to 5 meters long. There are two types of polyps living in a colony. Inside they are responsible for reproduction and digestion of food, and outside they are the most dangerous in this family, they catch prey, protect the coral, and sting anyone who touches them. They can seriously injure the skin if touched. Often after burns, long-lasting ulcers form. They look like branchy trees, but don't break off a piece as a souvenir; around the world, about 1,500 people suffer from their burns.

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Unusual coelenterates Portuguese man of war(Portuguese man-of-war), or physalia (Order Siphonophora) This is a type of colonial hydroid of complex structure, a huge floating colony of polyps and jellyfish, numbering several hundred individuals, each performs some function, some obtain food, others digest it, others protect the colony from enemies , but outwardly it looks like one organism. The body is 9 - 35 cm long, rises about 15 cm above the water, drifts into the sea, lives for several months. Tentacles up to 30 meters long blend in color with the water, are almost invisible and very dangerous. The venom of physalia is dangerous for humans, similar to the venom of a cobra; physalia washed ashore retain the ability to sting; tentacles that have been in the refrigerator for six years have retained their toxic properties. The most poisonous varieties of physalia live in the Indian and Pacific Oceans; their poison is deadly to humans. The ship got its name back in the 15th century in honor of the flotilla of Henry the Navigator.

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Unusual coelenterates Porpita and Velell - these animals, like the physalia, are called swallowtails, but belong to the order Chondrophora - these are floating colonies found in warm seas. Porpita ("blue button") consists of a float and a hydroid colony and is often mistaken for jellyfish, but is a hydroid colony. The goads of the porpyra are not as powerful as those of the physalia; the mouth is located under the float, used for eating (zooplankton, organic remains) and for removing food waste. Velella lives in the open sea and is up to 12cm long. along the long axis of the disk. Velella has a high triangular outgrowth - a sail, with its help it moves, 8 or more tentacles. Velellas often gather in huge flocks. The planus crab “travels” on it and takes food and finds protection from enemies. Predatory gastropod Yantina attaches to the lower part of the velella and eats away at its tissue until it dies. Many organisms use velella as a "raft" and food. Porpita Velella

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Unusual coelenterates. Is this a plant or an animal? Order Anemones or Sea Flowers - Anemones (Actiniaria) - class Coral Polyps. About 1000 species of sea anemones are known. Until the end of the 19th century, sea anemones were classified as plants; they look like beautiful flowers of the sea. The body is from a few millimeters to 1.5 meters in diameter; unlike corals, they lack a mineral skeleton; they often live alone rather than in colonies. At the top of the sea anemone is a mouth, the lower end is a “sole” - for attaching to underwater objects, tentacles for catching prey, if disturbed, the tentacles retract into themselves. Coloration is very variable depending on distribution. They are able to move very slowly along the bottom over short distances. They are more common in warm waters, although they are found everywhere. Gorgeous carpet anemone differs from other species in size, its diameter is up to 1 meter (a type of barrel with grass) Lives in the Indian and western parts Pacific Ocean. It is a predator, like all sea anemones, and can cause serious burns to humans. Magnificent carpet anemone (Heteractis magnifica) Beautiful anemones - flowers of the sea

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Symbiosis of sea anemones with other organisms Sea anemones can enter into relationships with hermit crabs, fish (for example, clown fish), crabs, mollusks and other animals. Clown fish are covered with a mucous membrane that protects them from the poison of the anemone tentacles. Sea anemone is a reliable shelter for them from large predatory fish, in turn, the fish eat among the tentacles and pieces of food fall into the sea anemone, and the fish also push air between the tentacles with their fins, improving the gas exchange of the sea anemone, thus there is a benefit for both organisms. The hermit crab, discovering an anemone, transfers it to its shell, the crab provides the anemone with leftover food and transports it from place to place, and the sea anemone’s burning tentacles repel the attack of predators. Anemone and fish - clown Anemone and crab - hermit

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Interesting things about hydra. Why is hydra called hydra? Hydra symbionts. The Hydra has an amazing regenerative ability, which is how it got its name, by analogy with the mythical Lernaean Hydra, which restored its head every time it was cut off. You can decapitate the hydra and the mouth cone with tentacles will form anew. If you cut a hydra lengthwise into two halves, the whole hydra will be restored, etc. It is interesting that pieces of the hydra's body, rubbed through muslin and then merged into a single mass, turn out to be capable of regeneration. In the reservoirs of Russia there are 4 species of hydra, similar to each other, the body length is usually 1-20 mm. In the so-called green hydra Hydra (Chlorohydra) viridissima, symbiotic algae of the genus Chlorella - zoochlorella - live in the cells of the endoderm. In the light, such hydras can live for more than four months without food.

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LUMINOUS CELENTARITIES Luminous coelenterates are very diverse. The Crossota and Pantachogon jellyfish have many long tentacles on the edge of the umbrella and swim in short, quick bursts. The Meator jellyfish has lost its medusoid shape and looks like a transparent ball with a dark core. Lives at a depth of 1 to 6 km, in darkness and cold. Very beautiful glowing jellyfish Phosphoric Olindias (Olindias phosphorica) belongs to the Hydroid class, it is a rare animal, like a shining umbrella. It lives off the coast of Japan, Argentina, and Brazil. The length of the umbrella is 15 cm in diameter, it feeds on small fish and plankton. In humans, contact with it causes mild skin irritation. Most deep sea jellyfish are red or Brown, thanks to the special pigment luciferin, the oxidation of this fat-like substance by the enzyme luciferase is accompanied by luminescence. Phosphoric olindias - a miracle of nature Pantahogon

Coelenterates, like sponges, first appeared on earth more than 500 million years ago. They have multicellular organisms and the most in different forms. The coelenterates include sea ​​anemones, jellyfish and corals.

general characteristics

The body of coelenterates has the shape of a sac with a hole, which is surrounded by tentacles. They can face up like polyps or down like jellyfish. Coelenterates and sponges have a radially symmetrical body, that is, body parts are located around a central axis.

Nutrition

The internal cavity in the body of coelenterates communicates with the surface through a single opening, which serves for the intake of food and the release of undigested residues. Around the hole there are tentacles that capture, paralyze and pull prey inside.

Habitat

Coelenterates live in warm tropical seas; Some of them lead a sedentary lifestyle, others are free-swimming. Thus, hydroids can be both stationary (polyps) and floating (jellyfish); The scyphoid class consists only of jellyfish, and the class of coral polyps includes only motionless forms - polyps living separately or in colonies. Coelenterates are multicellular organisms characterized by a simple structure and radial symmetry. This structure is very convenient for animals that are not able to move freely: both food and enemies can appear from anywhere, so it is important to be prepared for attack or defense from any side.

The body of all coelenterates consists of one internal cavity, communicating with the surface through an opening - the mouth, the walls of which perform respiratory functions, serve for eating and removing processed products.

The mouth is surrounded by tentacles containing nettle, or stinging, cells. When a small animal touches one of them, a tubular fiber containing a poisonous liquid is thrown out. Hundreds of such threads dig into the victim, and the tentacles pull it, paralyzed, into the oral cavity. Thus, coelenterates are predators; becomes their prey small fish and crustaceans. Due to the specificity of their body structure, coelenterates are well camouflaged at the bottom and become a sudden trap for their victims.

The type of structure of coelenterates (there are two main types - polyps and jellyfish) can change during the development of the animal: the larva can be motionless, in the form of a polyp, and the adult can be mobile, like a jellyfish; and vice versa, the larva is mobile, and the adult animal has a stationary polyp form, like in corals.

The body walls of coelenterates consist of two rows of cells: one external, called ectoderm, and the other internal, called endoderm. Between the two rows of cells is a jelly-like layer with a lot of water.

The ectoderm consists of elongated muscle cells, and the endoderm is round. The shooting motion characteristic of jellyfish is achieved by the activity of these two rows of cells, which stretch and contract. Such movements allow the jellyfish to move forward: compression pushes the water out from under the umbrella, and the jellyfish receives a jet push, like a rocket.

The remaining cells have transformed into nerve cells and envelop the surface of the body with a mesh, giving the jellyfish sensory organs.

Coelenterates are divided into three large classes: hydroid, scyphoid and coral polyps.

There are 2,700 hydroid species; They are small in size, reproduce only by budding and come in two forms - polyps and jellyfish. They live isolated, like hydras, or in colonies, like hydrants.

Jellyfish belong to the scyphoid class. bright colors with large umbrellas; they live only in isolation. There are about 250 species of scyphoids: the largest representative of this class is the Arctic cyanea, whose umbrella is more than 2 m in diameter.

Coral polyps are the class of coelenterates with the largest number of species - 6500 species. They are found only in the form of polyps, can be solitary, like sea anemones or sea anemones, but more often live in colonies, like corals and madrepores.

The most popular of the coral polyps, red coral, has been known since ancient times in China and Japan; in Europe it began to be widely used for making jewelry even before our era. For the inhabitants of Tibet in the 13th century BC, red coral was a bargaining chip. In addition, back in late XIX centuries, corals have been attributed various healing properties: Coral powder was considered a panacea for many diseases.

Kinds

Noble, or red, coral is found mainly in the Mediterranean Sea at a depth of 20 to 200 m in colonies 10-14 cm high. Other representatives of this species, living in the Sea of ​​Japan, reach 1 m in height and weigh about 40 kg.

For thousands of years, noble coral has been used to make small decorative items and jewelry. It is even found in burials of the 4th century BC.

The part of the coral visible to us is an external skeleton, very hard and fragile, formed by small polyps. They form branched colonies that resemble small trees, especially when they move their tentacles, similar to the corollas of flowers.

Type	Class	Subclass	Squad	Family	Genus	View
Coelenterates	hydroid					hydra
	scyphoid					jellyfish
	coral polyps	Alcyonaria, or eight-rayed corals				corals, horn corals
		cortical or six-rayed corals				madrepores, sea anemones

Hydra lives in fresh water. Due to its six thin tentacles, which are six times longer than the size of the hydra itself, it closely resembles algae. Looking at her, it is difficult to imagine that this innocent animal was identified in Greek mythology with a monstrous snake with nine heads that grew again every time they were cut off.

The structure of the jellyfish is interesting because this animal is 95% composed of water, and organic matter makes up only 5% total mass. If big jellyfish throw it onto land, it will completely “melt”, and after a few hours there will be nothing left on the sand except a small wet spot.

Xenia is a very beautiful coral, like a tree, sparkling with its feathered tentacles.

The sea pen, unlike its coral relatives, has a soft and flexible external skeleton, which makes it look like an elegant goose feather. It emits a bright blue-green color, which is why it received the Latin name pennatula phosphorea, translated into Russian as “phosphorous”.

The verrucoso anemone is a medium-sized sea anemone (about 3 cm) with a characteristic knobby leg. In case of danger, she hides her tentacles in her mouth and becomes like a hard ball.

Gorgonaria unicella cavolinii is a very rare coral found in the Mediterranean Sea. It lives in large colonies, and its branched “crown” reaches 70 cm in length. Unfortunately, the beauty of this coral attracts the attention of poachers.

In the Mediterranean Sea you can find Caryophylla clava, an isolated madrepora with a thin transparent body.