In this article, we will consider who a pond snail is, what features it has, where it is found, and much more about this wonderful mollusk. What types of pond snails exist and what do they look like.

Any from pond snails, whether ordinary, small or large, is a snail that lives in ponds and gardens where there is enough moisture.

Large and small pond

The large pond snail belongs to the class of gastropods, which is the most numerous and diverse in comparison with other classes of gastropods. There are more than 90 thousand species of such mollusks in nature, and their habitat is not only ponds, but also the sea and land.

A large pond snail is about 5 cm long and many distinctive features from brothers.

Let's talk about the external structure of a large pond snail. It consists of three parts, which are noticeable and perfectly distinguishable between each other. The body outside the shell is covered with a mantle to protect the internal mucosa, the shell of a mollusk is twisted for convenience in a spiral of 5 turns. This structure of the shell provides reliable protection of the body from irritants, mechanical damage. . The sink contains lime for the basis of the structure of spirals, and on top of it is covered with an organic substance of a horn-like type (such is on the horns of cattle, etc.).

Due to the structure of the shell, he received an asymmetric body for better accommodation in the "protection", the connection of the shell with the body is carried out due to the muscle. The muscle ensures that the animal is drawn into the shell, and with the help of a pronounced leg, the mollusk can crawl back.

In the internal structure pond snails of any type, everything is arranged simply. The main organs are:

1. digestive complex;
2. leg;
3. eyes;
4. excretory and respiratory system;
5. sole and mucus secretion glands.

The snail feeds on plant food in a crushed form, then food from the tongue (has a “grater”) passes into the throat, is processed by the secretion of splitting and processed in the stomach and intestines.

The circulatory system is open, and the molluscs move due to the powerful leg, which glides over any surface thanks to the secret secreted by the glands.

These animals are unique and do not need to be killed. . They don't harm a person, nor gardens, because they feed on plant foods that are easily processed (that is, weeds of the ephemeral type (wheatgrass, wood lice). Snails also have healing properties, they are proper nutrition and application secrete mucus that nourishes human skin and regenerates epithelial cells.

Small pond snail

Who are the puddlers in general, you know from the previous paragraphs, now we will talk about small things. In nature, there are several small pond snails:

Small snails are in all gardens, are small in size and beautiful appearance. Be supportive of snails, they do no harm, more good.

common pond snail

There is an ordinary pond snail in the middle lane - Russia, Europe. The pond snail has a large size, one shell is 7 cm, not including the body. The pond snail breathes with nothing more than miniature lungs, the circulatory system is not closed, they feed on hard plant foods, detritus and midges. External structure does not differ from a large pond snail, except that the body does not always correspond to the size of the shell, sometimes smaller than the shell. The color of the shell is mother-of-pearl, brown. Body color - brown, gray, white.

Snails can easily survive both in nature and in the artificially created environment of a terrarium, aquarium. The snail moves thanks to the secretion of mucus and the outer sole, which allows it to move quickly enough over various distances. Snail mucus is rarely used in cosmetology, but most often the mollusk is kept for decoration.

Mollusks are attached to people - breeders, so if you fell in love with a snail, then do not give it to others, otherwise the weak heart of the animal will not stand it.

And now let's take a look at the photo of the pond

Snails big pond

Found in Russia and Europe different types pond snails. Among them, the largest is the common pond snail, the shell of which can reach 7 centimeters. All species breathe with lungs, therefore, from time to time they are forced to swim to the surface. You can often observe how the pond snail, the photo of which is presented in this article, slides smoothly and slowly along the lower part of the surface water film, picking up oxygen from the air.

If the mollusks, “suspended” in this way, are somehow disturbed, they immediately release an air bubble from the respiratory hole and fall like a stone to the bottom. The eared pond snail is the closest relative of the common one. Its shell reaches 2.5 centimeters, which depends on the abundance of food and the temperature in its reservoir.

The common pond snail and other species of its family (in addition to those listed above, in our reservoirs you can find ovoid, small and marsh) are very variable. In this case, the shapes, sizes, thickness of the shell, color of the body and legs of snails vary. Along with those that have a strong shell, there are species with a very fragile, thin shell that breaks even with the slightest pressure. There can also be various forms of a curl and mouth. The color of the body and legs varies from sandy yellow to blue-black.

Structure

The body of the mollusk is enclosed in a spirally twisted shell, which has a mouth and a sharp top. The shell of the common pond snail is covered with a lime layer of a horn-like greenish-brown substance. It is a reliable protection of his soft body.

In the body of a snail, 3 main parts can be distinguished: the leg, head and body - although there are no sharp boundaries between them. Only the front part of the body, leg and head can protrude from the shell through the mouth. The leg is very muscular. It occupies the abdominal area. Such snails are called gastropods. At the same time, sliding on objects with the sole of the foot or hanging to the lower film of water, the mollusk smoothly moves forward.

The body at the same time copies the shape of the shell, adjoining it very closely. It is covered in the front part by a mantle (a special fold). The space between it and the body is called the mantle cavity. The torso in front passes into the head, which has a mouth on the underside, and two sensitive tentacles on the sides. A pond snail, when lightly touched, instantly draws its leg and head into the shell. Near the bases of the tentacles there is one eye each.

Circulation

The common pond structure has a rather interesting structure. So, he has a heart, which pushes the blood into the vessels. In this case, large vessels are subdivided into small ones. And of them already blood is coming in the gaps between the organs. Such a system is called "unclosed". Interestingly, the blood washes each of the organs. Then she again gathers in the vessels that lead to the lung, after which she goes directly to the heart. In such a system, it is much more difficult to ensure the movement of blood than in a closed one, since it slows down between organs.

Breath

Despite the fact that the snail lives in water, it breathes atmospheric air. To do this, the common pond snail, the structure of which is described in this article, floats to the surface of the reservoir and opens a round breathing hole at the edge of the shell. It leads to the lung - a special pocket of the mantle. The walls of the lung are densely braided. In this place, carbon dioxide is released and the blood is enriched with oxygen.

Nervous system

This mollusk has a near-pharyngeal concentration. From them, the nerves extend to all organs.

Nutrition

The snail's mouth leads to the pharynx. There is a muscular tongue covered with teeth ─ the so-called grater. The common pond snail, the photo of which can be viewed in this article, scrapes off plaque from all kinds of microorganisms that form on various underwater objects, and also rubs various parts of plants. Food from the pharynx travels to the stomach and then to the intestines. The liver also aids in its digestion. In this case, the intestine opens with an anus into the cavity of the mantle.

movements

If the caught pond snail is put in a jar, it immediately begins to actively crawl along its walls. At the same time, a wide leg extends from the shell opening, which serves for crawling, as well as a head with two long tentacles. By sticking the sole of the foot to various objects, the snail glides forward. In this case, sliding is achieved by wave-like, smooth contractions of the muscles, which can be easily observed through the glass of the vessel. Interestingly, the common pond snail can wander along the lower surface of the water, as we have already discussed above. At the same time, it leaves a thin tape of mucus. It stretches across the surface of the water. It is believed that snails moving in this way use liquids, hanging from below to an elastic film that forms on the surface due to this tension.

Such crawling can be easily observed on the calm surface of the reservoir, going on an excursion or relaxing in nature.

If the pond mollusk, crawling in this way, again plunges into the water under a little pressure, it will be seen how it again, like a cork, rises to the surface. This phenomenon is easily explained: there is air inside the respiratory cavity. He supports the cochlea as the Prudovik can compress his respiratory cavity arbitrarily. In this case, the mollusk becomes heavier, therefore, sinks to the very bottom. But when the cavity expands, it floats to the surface along a vertical line without any push.

Try to immerse a pond snail floating on the surface of a reservoir in water and disturb its soft body with a touch of tweezers or a stick. The leg will immediately pull back into the shell, and air bubbles will come out through the breathing hole. Further, the mollusk will fall to the bottom and will not be able to independently rise to the surface in any other way than climbing on plants, due to the loss of the air float.

reproduction

The pond snail mollusk is a hermaphrodite, although its fertilization is cross. The snail lays eggs that are enclosed in slimy, transparent cords attached to algae. Eggs hatch into small pond snails with very thin shells.

If you still decide to start an ordinary pond snail, then you need to understand that a water temperature of about 22 ˚С and its moderate hardness are considered a prerequisite for its maintenance.

Gastropods are the most numerous and diverse group of mollusks. It has about 90,000 species living in the seas, fresh waters, on land. Most of them have a one-piece shell.

One of the representatives of this class lives in lakes, ponds and river backwaters - a large pond snail about 5 cm in size.

External structure

In the pond snail, all three parts of the body are clearly distinguishable: head, leg and bag-shaped body. The top of the body is covered with a mantle. The pond snail has a spiral, twisted in 4-5 turns shell that protects the body of the animal. The shell is made of lime, and on top is covered with a horn-like organic matter. In connection with the spiral shape of the shell, the body of the pond snail is asymmetric, since in the shell it is also curled into a spiral. The shell is connected to the body by a powerful muscle, the contraction of which draws the animal into the shell.

The leg of the pond snail is well developed, muscular, has a wide sole. The animal moves slowly sliding over plants or soil due to wave-like contraction of the leg muscles. The abundant mucus secreted by the skin glands of the foot facilitates smooth gliding.

Internal structure

Digestive system

In the mouth, on a special mobile outgrowth resembling a tongue, there is a grater with horny teeth. With their help, the pond snail scrapes off the soft parts of plants and microscopic algae deposits on underwater objects. There are salivary glands in the pharynx, the secret of which is processed food.

From the pharynx, food enters the stomach through the esophagus. The ducts of the liver flow into it. The stomach passes into the intestine, which makes several loops and ends with an anus at the front end of the body above the head.

Respiratory system

The body of the animal is covered with a mantle on the outside and closely adheres to the inner surface of the shell. Part of the mantle forms a kind of lung, numerous blood vessels develop in its walls, and gas exchange occurs here. The pond snail breathes atmospheric oxygen, so it often rises to the surface of the water and opens a round breathing hole on the right at the base of the shell. Next to the lung is the heart.

Circulatory system

The circulatory system is open, the blood is colorless. The heart consists of two sections - the atrium and ventricle, and blood vessels. Blood flows not only through the vessels, but also in the cavities between the organs. A large vessel, the aorta, departs from the heart. It branches into arteries. Then the blood enters the small cavities among the connective tissue. There, the blood gives off oxygen, is saturated with carbon dioxide, enters the veins and goes through them to the lung.

Here the veins branch into numerous small vessels - capillaries. The blood is enriched with oxygen and gets rid of carbon dioxide. Blood rich in oxygen is called arterial, and poor in oxygen and saturated with carbon dioxide is called venous. Then the blood is collected in the veins and enters the heart. It contracts 20-40 times per minute.

excretory system

Due to the asymmetry of the body, the pond snail retains only the left kidney.

At one end, it communicates through a wide ciliated funnel with the pericardial sac, where waste products accumulate, and at the other, it opens into the mantle cavity on the side of the anus.

Nervous system

The nervous system of molluscs is scattered-nodal type. It consists of five pairs of nerve nodes (ganglia), interconnected by nerve bridges, and numerous nerves.

In connection with the twisting of the body, the nerve bridges between some nodes form a cross.

sense organs

On the head of a pond snail, there are organs of touch - tentacles, there are also tactile cells in the skin. The pond snail has one pair of tentacles. There are eyes - they are at the base of the tentacles. There are also organs of balance.

Reproduction. Development

Fertilization in the pond snail is internal. This animal is a hermaphrodite. The single gonad produces both sperm and eggs. They reproduce by eggs that are laid on aquatic plants or other objects. Fertilized eggs are covered with a common mucous membrane, securely attached to the substrate. Each animal lays about twenty clutches during the year.

After twenty days, tiny animals appear from the eggs. They grow rapidly, eating plant foods.

The pond snail becomes sexually mature at the end of the first year of its life. It is also interesting that when the reservoir (in which pond snails are found) dries up, not all mollusks die. Some secrete a dense film that closes the opening of the shell. In this state, the pond snail can live without water for about two weeks.

The habitat of Lymnaea stagnalis is very extensive - water bodies of North Africa and North America, Asia, and Europe.

The snail Prudovik Ordinary is able to live both in fast streams and in swamps, but it feels best in the coastal part of lakes. The pond snail actively crawls along the bottom of the reservoir and coastal vegetation, and sometimes goes out onto wet meadows.

The main difference between this one is that her eyes are at the base of the antennae.

The sink of Prudovik has Brown color, which sometimes reaches dark. The base of the shell is quite fragile, the number of whorls varies within 4-5, the shell dimensions are up to 55 mm in height and up to 30 mm in width. Lymnaea stagnalis are able to move vertically (by secreting a path of mucus, they crawl along it in all directions).

Snails breathe atmospheric air with the help of a lung (a special section of the mantle cavity). To renew the air in the lung cavity, the mollusks rise to the surface of the water and breathe with the help of the edge of the mantle rolled into a tube.

In oxygen-rich water, pond snails are able to live at depth without rising to the surface. In this case, the lung is filled with water, through which gas exchange takes place.

The snail Prudovik feeds on both plant food and small insects and microorganisms. Quite often you can see snails eating the foliage of aquatic and coastal plants. If the number of molluscs in the reservoir increases greatly, then this is very harmful to the surrounding plants.

In an aquarium, Prudovik Ordinary can be fed with cabbage stalk, lettuce or raw potatoes.

Many freshwater inhabitants are not averse to eating this snail, as well as its caviar.

reproduction

By nature, Lymnaea stagnalis are hermaphrodites, so the eggs are fertilized both by their sexual products and other snails.

at one time the snail lays a large number of eggs enclosed in transparent mucous masonry.

In an aquarium, reproduction of the pond snail is difficult, since most of the eggs laid are eaten.

The Prudovik snail reaches puberty when its shell grows up to 20mm in length.

A representative of the family of freshwater molluscs of the sedyachevy order. It has an elongated, strongly pointed shell towards the apex, curled to the right, as a rule, thin and translucent. The volutes of the shell expand very rapidly and the latter, the so-called belly, occupies the largest part of the shell. Its color is pale yellowish.
The pond snail belongs, like the coil, to the number of mollusks with pulmonary respiration and therefore from time to time floats to the surface to inhale atmospheric air. Its body is greenish-dark gray with yellow spots. The head is equipped with two triangular flat tentacles, at the base on the outer side of which there are eyes. The leg is shorter than the coil leg, but much wider. From the leg, the body inside the shell rises upward in a spiral and forms a kind of sac closer to the shell opening, containing a mass of vessels and serving as a respiratory organ. On the right side of it is an air inlet, which is closed by tightly closing muscles. The hole and the entire respiratory organ is easily visible when the animal, crawling over the plant, turns and often crawls almost completely out of the shell. This often happens at a time when the pond snail, like a coil, crawls with its foot on the surface of the water, which it does in order to breathe atmospheric air.
Under the head is a mouth opening, consisting of the upper jaw and two lateral sickle-shaped ones. A long tongue is also placed here, which rakes in algae. This is especially clearly seen when the pond snail crawls along the glass of the aquarium.
Prudoviks are bisexual animals, and therefore they can be found mated in 6-10 pieces together. Pond snails lay their eggs on the lower surface of floating leaves, on glass in an aquarium, and on various objects. Caviar is connected not in the form of a cake, but in a worm-like or oval shape, similar to an icicle. From May to August they lay up to 20 such icicles, and each of the icicles contains 20-100 eggs. The eggs are transparent. The development of the embryo proceeds rapidly, and after a few days the embryo, covered with ciliated hairs, begins to rotate rapidly.
The emergence of snails from eggs takes place no earlier than twenty, and sometimes even after forty days, which, in all likelihood, depends both on the temperature of the water and on the strength of the light.
With the gelatinous mass of eggs of these snails, a remarkable phenomenon is sometimes observed. It is covered with some kind of mold - small cilia with a pin-shaped thickening at the end, apparently, lily-of-the-valley suvoys. These beings seem to contribute to the destruction of this mass.
The snail reaches a large size, and therefore it is not very convenient for the aquarium. This inconvenience is increased by the fact that it grows so rapidly and a short time reaches large sizes.
Together with the speed of growth, this snail is characterized by voracity, the victims of which are aquarium plants, and plants that are distinguished at the same time by softness and juiciness are especially preferred. In his youth, the pond snail is not dangerous, since he is small and his appetite is negligible.
Prudoviki are able to eat the corpses of their own brethren.
The same genus of pond snails also includes Limnea stagnalis (common pond snail), even larger than the one above.