The family of pond snails includes well-known and widely distributed throughout the world freshwater lung mollusks.
Of the large number of species belonging to this family, the common pond snail is best known for its large size, the largest specimens of which reach 7 centimeters. From early spring to late autumn, these snails can be observed in ponds, in river backwaters, and small lakes. It is interesting to watch how these bulky snails crawl on aquatic plants or along the bottom of a reservoir. There are especially many of them in the middle of summer among the floating leaves of egg capsules or water lilies.
Pond snails are omnivores, therefore, crawling along the leaves and stems of aquatic plants, they scrape off radula algae from them, and at the same time they absorb small animals that they come across on their way. Prudovik is one of the most voracious inhabitants of fresh waters. It eats not only plants and animals, but also corpses.
You can often see how a pond snail, having risen to the surface of the water and hung to it from below with a wide sole of the foot, due to the surface tension of the water film, slowly and smoothly slides in this position. It is not in vain that pond snails rise to the surface of the water. Although they are aquatic organisms, but, like all pulmonary mollusks, they breathe with the help of a lung and are forced to rise to the surface in order to “sip” air. The respiratory opening of the pond snail, leading to the lung cavity, is wide open. The presence of lungs in pond snails indicates that these animals originated from land mollusks and have already returned to living in water for the second time.
Reproduction of pond snails
When mating, pond snails mutually fertilize each other, since, like all lung mollusks, they are bisexual creatures. Snail eggs are laid in the form of long, gelatinous, transparent cords, which are glued to various underwater objects. Sometimes eggs stick even to the shell of another individual of the same species. Pond eggs are a complex formation, since the egg cell is immersed in a mass of protein, and is covered with a double membrane on top. The eggs, in turn, are immersed in a slimy mass, which is dressed in a special capsule, or cocoon. A strand extends from the inner wall of the cocoon, attached at the other end to the outer shell of the egg, as a result of which it appears, as it were, suspended from the wall of the cocoon. The complex structure of the egg clutch is also characteristic of other freshwater lung mollusks. Thanks to these devices, the egg is provided with nutritious material and protected by powerful shells. Inside these shells, the development of pond snails takes place without the stage of a free-swimming larva. It is likely that such protective adaptations of the eggs of pond snails were inherited from their land ancestors, where these adaptations were more important than when living in water.
The number of eggs in a clutch varies quite widely, as does the size of the entire clutch - the slimy cord. Sometimes you can count up to 270 eggs in one cocoon.
The pond snails are extremely variable, and the size of the mollusks, the shape of the shell and its thickness, and the color of the legs and body vary greatly. Along with large representatives, almost dwarf forms are known, undergrown due to unfavorable conditions and malnutrition. In some pond snails, the shell has thick, hard walls; there are also forms with an extremely thin and fragile shell that breaks at the slightest pressure. The shape of the mouth and whorl is highly variable. The color of the legs and body of the mollusc varies from blue-black to sandy-yellow.
This "tendency" to variability played a big role in the evolution of pond snails. Within the species, a large number of local varieties have arisen that differ in these characteristics, and it is often very difficult to determine whether this is a geographical subspecies or a variation due to specific habitat conditions in a given reservoir.
Types of pond snails
Along with the common pond snail, a permanent inhabitant of our inland waters, there is another, also extremely variable species - the eared pond snail. In addition, ovoid pond snail, marsh pond snail and some others live in stagnant reservoirs.
Interestingly, pond snails living at considerable depths have been found in the deep lakes of Switzerland. At the same time, they are already deprived of the opportunity to rise to the surface to breathe air and have developed another adaptation. The lung cavity of these snails is filled with water, and they breathe oxygen dissolved in water. The absence of gills in pond snails, unlike primarily aquatic mollusks, again proves their origin from land snails.
Close to pond snails is the only representative of our fauna from the genus mixas, which differs from them in a very thin and fragile shell, almost completely covered with a mantle. Thus, the shell of this mollusk turned from the outer into the inner. These snails live mainly in floodplain ponds and lakes, where they sometimes breed in large numbers. However, in the middle of summer, snails disappear, as their life cycle ends in one season.
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.
The large pond snail is about 5 cm long and has many distinctive features from the brothers.
Let's talk about the external structure of a large pond snail. It consists of three parts that are noticeable and perfectly distinguishable from 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:
- digestive complex;
- leg;
- eyes;
- excretory and respiratory system;
- sole and mucus secretion glands.
The snail feeds on plant foods in crushed form, then the 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 such as ephemera (wheatgrass, wood lice). Also, snails have healing properties, when properly fed and used, they 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 in 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. The 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. Shell color - 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
The small pond snail is similar to the common pond snail, only the shell size is smaller (see appendix fig. 25). The small pond snail lives in temporary reservoirs - puddles, ditches, swampy meadows, sometimes even on moist soil near the water's edge. In a word, there are many places where a temporary resident is found.
It feeds, like its relative, on algae and microorganisms.
The small pond snail is distributed throughout Europe and Northern Asia, like the common pond snail.
gastropods;
coil family;
horn coil.
Coils (Planorbis) belong to the class of gastropods (Gastropoda), to the order of pulmonary (Pulmonata), to the family of coils (Planorbidae).
The coil can be distinguished at a glance due to its extremely characteristic
shell, curled in one plane in the form of a spiral cord.
The horn coil (P. corneus L.) attracts the most attention, the largest among the others (shell diameter 30 mm, height 12 mm), reddish-brown. This coil is found everywhere in both pond and lake waters.
The movements of the coils resemble the movements of pond snails. Crawling, snails expose their dark soft body far from the shell and move along underwater objects with the help of their wide flat legs. On the head there is a pair of thin tentacles, at the base of which the eyes are placed. Coils, just like pond snails, can wander along the surface of water bodies, being suspended from a film of surface tension of a liquid.
Coils breathe atmospheric air, taking it into the lung cavity formed by the walls of the mantle. The respiratory opening leading to the indicated cavity opens on the side of the body, near the edge of the shell. It opens when the coil rises to the surface of the water for a supply of air. With a lack of air, the coil uses a special leathery outgrowth, which is placed on the body near the pulmonary opening and plays the role of a primitive gill. In addition, the coil, in all likelihood, breathes directly through the skin.
Food. Coils feed on plant foods, eating parts of plants that are scraped off with a grater. Especially willingly, these snails eat green plaque from small algae, which forms on the walls of the aquarium. Outside, through the glass, it is not difficult to observe how the animal works with its grater, raking up plaque like a spatula. It is very possible that coils can also eat animal food. At least in captivity, they willingly pounce on raw meat.
Reproduction. Coils reproduce by laying eggs on the leaves of aquatic plants and other underwater objects. The masonry of the horn coil is constantly found on excursions and is so characteristic that it can be easily distinguished: it has the appearance of a flat gelatinous plate of an oval shape of yellowish or light brown color and contains several dozen round pinkish transparent eggs. After two weeks or more (depending on the temperature of the water), tiny snails hatch from the eggs, which grow quite rapidly. The caviar of coils, like other snails, is readily eaten by fish and exterminated by them in large numbers. Like the pond snail, coils are hermaphrodites.
The behavior of the coils during the drying of the reservoirs in which they occur is interesting. They burrow into moist silt, like the large horn coil (P. corneus). Sometimes this coil remains on the surface of the soil, sticking to the silt with its mouth, if moisture remains in it, or it releases a dense, water-insoluble film, which closes the shell opening. In the latter case, the body of the mollusk gradually shrinks, eventually occupying a third of the shell, and the weight of the soft parts drops by 40-50%. In this state, the mollusk can survive out of water for up to three months (marginal coil P. marginatus P. planorbis).
The body of the coil, like that of pond snails, is divided into three parts: head, torso and leg (see appendix fig. 26). The leg is a muscular abdominal part of the body, leaning on which the mollusk slowly glides. At the coils, the turns of the shell are located in the same plane. Coils are not as mobile as pond snails, and cannot be suspended from the surface film.
Coils live on plants in stagnant and slow-flowing reservoirs, in the same place as an ordinary pond snail, but rises to the surface of the water much less frequently.
beauty family;
larva of a beauty girl.
On a sunny day, blue lights flash up and then go out over the river (see appendix fig. 27). It is flitted by graceful dragonflies. At some point, they resemble helicopters.
The body is bronze-green, the wings of females are light smoky, those of males are almost entirely blue.
All dragonflies, wherever they are, wherever they fly, need water. They lay their eggs in the water. And only in water can their larvae live. The larvae do not look like adult dragonflies. They just have the same eyes.
Special mention must be made of the eyes of dragonflies. Each eye is made up of thousands of small eyes. Both eyes are large and protruding. Thanks to this, dragonflies can look in all directions at the same time. This is very handy for hunting. After all, dragonflies are predators. And their larvae, living in the water, too.
Dragonflies hunt in the air - they grab insects on the fly. The larvae live in the water, and here they also get food for themselves. But they do not chase prey, but lie in wait for it. The larva sits motionless or crawls slowly along the bottom. And some tadpoles or some insects swim by. The larva does not seem to care about them, but how this tadpole or insect turns out to be close. Once! She instantly throws out her long arm and grabs the prey, quickly pulling it to her.
"But insects don't have arms," you say. And you will be right. Yes, of course they don't have hands. But there is a very long lower lip with hooks at the end. The lip folds like a hand at the elbow when you press the brush to your shoulder. And while the larva watches for prey, the lip is not visible. And when the prey is close, the larva instantly throws out its lip to its full length - as if shooting it - and grabs a tadpole or an insect.
But there are moments when the larva needs to save itself. And here saves her speed. More precisely, the ability to move with lightning speed from place to place.
Some predator rushed at the larva. Another second - and the larva was gone. But where is she? Just been here, and now in a completely different place. How did she get there? Very simple. Activated her "jet engine".
It turns out that dragonfly larvae have a very interesting adaptation: a large muscular sac inside the body. The larva sucks water into it, and then throws it out with force. It turns out a water "shot". The water jet flies in one direction, and the larva itself in the opposite direction. Just like a rocket. This is how it turns out that the larva makes a lightning-fast jerk and slips out from under the very "nose" of the enemy.
After flying a few meters, the larva slows down, sinks to the bottom or clings to some plant. And again it sits almost motionless, waiting for the time when it will be possible to throw out the "hand" and grab the prey. And if necessary, it will re-launch its "jet installation". True, not everyone has a "jet engine", but only the larvae of large dragonflies.
A year later, the larvae of some dragonflies, after three years, the larvae of others climb out of some plant sticking out of the water to the surface. And then a small miracle happens: the skin of the larva bursts and a dragonfly appears from it. The most real and not at all like a larva.
The dragonfly will shed its skin like a suit, and even pull out its legs, like out of stockings. He will sit for several hours, rest, spread his wings and go on his first flight.
Some dragonflies fly far from their birthplace. But the time will come, and they will definitely return. Because they cannot live without a river or a lake, a pond or a swamp - without water, in a word. And the river, the pond, the lake also cannot live without these friends of theirs.
Dragonfly eggs are laid in water or in the tissues of aquatic plants. The eggs hatch into larvae of an extremely characteristic shape, interesting in their biological features. These larvae play an important role among other living material in freshwater excursions.
Dragonfly larvae are found everywhere in stagnant and slowly flowing water. Most often they are on aquatic plants or at the bottom, where they sit motionless, sometimes move slowly. There are species that burrow into the silt.
The larvae move either by swimming or crawling. Larvae from the group of buttercups swim differently than others. An important role in the movement is played by the expanded gill plates located at the posterior end of the abdomen, which serve as an excellent fin. Bending its long body, the larva beats the water with this fin and rapidly pushes forward, moving like a small fish.
Dragonfly larvae feed exclusively on live prey, which they watch motionless for hours, sitting on aquatic plants or at the bottom. Their main food is daphnia, which are eaten by them in large quantities, especially by younger larvae. In addition to daphnia, dragonfly larvae willingly eat water donkeys. They are less willing to consume cyclops, perhaps due to the small size of the latter.
The favorite food of dragonfly larvae are also mayfly larvae and mosquito larvae from the families of culicids and chironomids.
They also eat the larvae of aquatic beetles, if only they are able to master them. However, they do not touch large larvae of swimmers, well-armed and no less predatory, even if they are planted in a common vessel with them.
Dragonfly larvae do not chase their prey, but sit motionless on aquatic plants or on the bottom and guard the prey. When a daphnia or other animal suitable for food approaches, the larva, without moving from its place, throws out its mask with lightning speed and grabs its prey.
For grasping prey, the larvae have a wonderful mouth apparatus, which is aptly called "masks". This is nothing more than a modified lower lip, which looks like grasping tongs, sitting on a long lever - a handle. The lever is equipped with a hinge joint, thanks to which the whole device can be folded and, in a calm state, covers the underside of the head like a mask (hence the name). Noticing the prey with its large bulging eyes, the larva, without moving, aims at it and with a lightning movement throws its mask far forward, grabbing the prey with remarkable speed and accuracy. Captured prey is immediately devoured with strong gnawing jaws while the mask brings the prey to the mouth and holds it like a hand while eating.
Breath. Dragonfly larvae breathe with tracheal gills. In lute-type larvae, the gill apparatus is located at the posterior end of the abdomen in the form of three thin, expanded plates pierced by a mass of tracheal tubes. Shortly before the adult dragonfly hatches, the larvae also begin to breathe atmospheric air with the help of spiracles that open on their upper side of the chest. This explains why adult larvae often sit on aquatic plants, exposing the front end of their body out of the water.
Luke-type larvae have the ability to discard gill plates if they are infringed. This is easy to verify by experience: put the larva in the water and squeeze the gill plate with the tip of tweezers. This phenomenon is called self-mutilation (autotomy) and is well known in many animals (spiders, lizards, etc.). For this reason, it is necessary to catch larvae from the water that lack 1 - 2, and sometimes all 3 tail plates. In the latter case, breathing takes place, in all likelihood, through a thin skin that covers the body. The torn off plate is restored again after some time, due to which it is possible to observe larvae with gill plates of unequal length. It should be noted that in Calopteryx one of the plates is always shorter than the other two, which is not an accidental circumstance, but a generic feature.
Dragonflies reproduce using eggs that the females lay in the water. The clutches of different species are very diverse. Dragonflies such as yoke and buttercups drill their eggs into the tissues of aquatic plants. In this regard, their eggs also have a characteristic oblong shape, and the stuck end is pointed. In the place where the egg is stuck, a trace remains on the surface of the plant, which then takes the form of a dark spot or scar.
Since the eggs of different species of dragonflies are placed on the plant in a certain order, peculiar, sometimes very characteristic patterns are formed.
The suborder of dragonflies is homoptera;
Lutka family; sunflower-bride.
A very slender, elegant, graceful dragonfly (see appendix fig. 28). The body is green, metallic-shiny. In females, the sides, breasts are yellow, and in males with a bluish-gray bloom.
There are no significant differences between dragonflies, and all descriptions of dragonflies and their larvae are the same, so in the previous chapter you can find all descriptions of both larvae and adults.
Mayfly Squad;
Mayfly ordinary.
On quiet summer evenings, when the sun's rays are no longer burning, some insects that look like butterflies, but with two or three long threads on their tails, swarm in the air near the banks of rivers, lakes and ponds (see appendix fig. 29). They either soar up, then freeze, stabilizing the fall with long tail threads, then, spreading their wide wings, slowly sink down. So they swirl over the shore, like a dense fog or cloud about ten meters high and about a hundred meters long. These swarms rush over the water like a storm. You will not see such an exceptional phenomenon every day, only in July-August it is repeated several times.
This is dancing, carrying out the mating flight, mayflies. Their wings and they themselves are so tender that it is simply amazing how they do not break during the flight. You involuntarily think that they will not live long. And this opinion is true: many mayflies live only one day. Therefore, they are called mayflies, and their scientific name comes from the Greek word "ephemeron" - fleeting.
After the mating flight, the females lay their eggs in the water and die. With such a short life, they do not eat anything.
Mayfly larvae develop in water. The larvae live longer, two to three years. And unlike an adult, they eat very well. And they feed on algae, decaying organic matter, small invertebrates and molt up to twenty-five times during development. Many fish feed on the larvae of mayflies, and various birds eat adult mayflies.
On examination, the quick, sharp movements of the larvae are primarily striking. When disturbed, it takes off headlong and swims very briskly, with three feathery caudal filaments richly pubescent with hairs (Cloon, Siphlurus) serving as fins. The legs serve mainly for attachment to aquatic plants. The quick movements of the mayflies probably serve as a defense against their many enemies, who actively hunt for these tender larvae. The color of the larvae, generally greenish, also plays a protective role, matching the color of the aquatic plants among which they huddle.
The respiration of larvae is easy to observe during excursions. It is of considerable interest as a good example of tracheal-gill respiration. The gills look like thin delicate plates that are placed in rows on both sides of the abdomen (Cloeon, Siphlurus). These delicate tracheal leaves are constantly moving, which can be perfectly seen in a larva sitting in water even without the help of a magnifying glass. Most often, these movements are uneven, jerky: as if a wave runs through the leaves, which then remain motionless for some time until a new wave. The physiological significance of this movement is quite clear: in this way, the flow of water washing the gill plates increases, and the exchange of gases accelerates. The larvae's need for oxygen is generally very high, therefore, in aquariums, the larvae die at the slightest damage to the water.
The food of the larvae is very diverse. The free-swimming, stagnant water forms most commonly encountered on excursions are peaceful herbivores, feeding on microscopic green algae (Cloeon, Siphlurus). Other species lead a predatory lifestyle and actively hunt for small aquatic animals. The food of many species of mayflies is still not well understood.
The phenomena of reproduction in mayflies are of great interest and have long attracted the attention of observers. Unfortunately, these phenomena on excursions have to be seen only by chance. As mentioned above, females drop their eggs into the water. The eggs hatch into larvae, which grow and molt many times (the Cloeon has more than 20 molts), and the rudiments of wings gradually form in them. When the larva completes its development, a winged insect hatches. At the same time, the larva floats to the surface of the reservoir, the covers on its back burst, and in a few seconds an adult mayfly emerges from the skin, which flies into the air. Since the process of hatching in larvae is often carried out simultaneously, the surface of those reservoirs where larvae are found in large numbers presents a wonderful sight during hatching, which has been described more than once in the literature: the surface of the water seems to boil from a multitude of hatching insects, and clouds of mayflies, like snow flakes hovering in the air. However, the winged insects that hatch from the larvae do not represent the final stage of development. They are called subimago and after a short period of time (from several hours to 1-2 days) they molt again, thus turning into imago (the only case among winged moulting insects). Sometimes on an excursion you can watch how a winged mayfly sits on some plant or even on a person and immediately sheds its skin.
Detachment ticks;
hydrachnida family;
The vast majority of ticks are very small animals, no more than one millimeter, only a few are larger, for example, our tick.
Common pond snail- lat. Limnaea stagnalis, a member of the phylum Mollusca, belongs to the class Gastropoda. A feature of the common pond snail, like all representatives of the pond snail family, is a kind of swimming in the water. A special organ (leg) during movement is directed upwards, protruding slightly on the surface of the water. So that an ordinary pond snail does not sink while moving, the middle of the leg bends down, thus acquiring the shape of a boat, while the animal's shell is directed down to the bottom. Such a peculiar movement is not yet clear to scientists.
Structure
The snail's eyes are located at the base of the second pair of tentacles. The breathing of an ordinary pond snail is carried out due to one lung, which is a modified mantle cavity. The air in the lungs, in a calm state of the mollusk, does not allow it to fall to the bottom. But if at this time you touch an ordinary pond snail, then it instantly releases air from the respiratory tract and instantly falls down. He also has one kidney and one atrium. The shell of an ordinary pond snail has the shape of a twisted spiral.
Characteristics of the animal:
Dimensions: the length of the mollusk is 5 - 7 cm.
Colour: Common pond snail has a variable color, from dark blue to yellow. The shell has a thin translucent structure.
Food and habitation
Ordinary pond snails are omnivorous animals, they can eat both plant and animal food, mainly algae, aquatic plants, uruti leaves, etc. Common pond snails are widely distributed throughout the globe, mainly on ponds, rivers, lakes, etc. They live at shallow depths.
Big pond snail - an inhabitant of fresh water. It has a cone-shaped, spirally twisted shell with 4-5 whorls, a sharp apex and a large opening - the mouth. The shell serves as protection for the soft parts of the body of the mollusk; muscles are attached to it from the inside. The shell consists of lime covered with a layer of greenish-brown horn-like substance. In body pond snail three main parts can be distinguished: the torso, head and leg, but there are no sharp boundaries between them. Through the mouth protrudes the head, the front part of the body and the leg. Leg at pond snail muscular. When undulating muscle contractions run along its sole, the mollusk moves. Leg pond snail located on the ventral side of the body (hence the name of the class - gastropods).
The body repeats the shape of the shell, closely adhering to its inner surface. Outside, it is covered with a skin fold - a mantle. In front, the body passes into the head. A mouth is placed on the underside of the head, and two sensitive tentacles are located on its sides. From touching them, the mollusk quickly draws its head and leg into the shell. Near the bases of the tentacles on the head are located along the eye.
Features of life processes: Prudovik feeds on aquatic plants. In the pharynx he has a muscular tongue covered with hard teeth. Prudovik from time to time sticks out his tongue and scrapes with it, like a grater, the soft parts of plants, which he swallows. Through the pharynx and esophagus, food enters the stomach and then into the intestine. The intestine curves in a loop-like manner inside the body and ends near the edge of the mantle with an anus. Unlike all previously studied animals at pond snail there is a digestive gland, the liver, whose cells produce digestive juice. So the digestive system pond snail more difficult than that of an earthworm.
Breathing is pulmonary. Periodically rising to the surface of the water, it fills the mantle cavity with fresh air through a round breathing hole. The walls of the lung are densely braided with blood vessels, here the blood is enriched with oxygen and carbon dioxide is released. Within an hour, the mollusk rises for breathing 7-9 times. Next to the lung is a muscular heart, consisting of two chambers - the atrium and the ventricle. Their walls alternately contract (20-30 times per minute), pushing blood into the vessels. Large vessels pass into the thinnest capillaries, from which blood exits into the space between the organs. Thus, unlike annelids, the circulatory system of the mollusk is not closed, since it communicates with the body cavity and the blood does not always flow through the vessels. From the body cavity, blood is collected in a vessel suitable for the lung, enriched with oxygen and enters the atrium. Blood pond snail colorless. The excretory organs are represented by one kidney. main part of the nervous system pond snail constitutes a peripharyngeal cluster of nerve nodes. Nerves depart from them to all organs of the mollusk.
Reproduction: Hermaphrodite. Lays a large number of eggs enclosed in transparent slimy cords. Which are attached to underwater plants. Eggs hatch into small mollusks with thin shells.
Loading...
