in Russia and Europe, there are different kinds of mollusks.Among them are the biggest - it truncatula ordinary sink can reach 7 cm.All kinds breathe easy, therefore, from time to time they have to swim out to the surface.You can often watch the snail truncatula, a photo that is presented in this paper, gently and slowly slide to the bottom of the surface film of water, picking up oxygen from the air.If
shellfish "suspended" in such a way that any disturbance, they will immediately discharged from the breathing hole bubble air and fall to the bottom of the stone.Eared truncatula - the closest relative of the ordinary.It sink up to 2.5 centimeters, depending on the abundance of food and the temperature in his pond.
mollusks and other common types of his family (except for the above, in our waters can be found ovate, small and marsh) are very volatile.Varies with the shape, size, thickness of the shell, the color of the trunk and legs snails.Along with those who have a strong sink, there are species with very fragile, thin shell, which breaks even at the gently pressed.There may also be a different shape of the navel and mouth.Colouring of the torso and legs varies from sandy yellow to blue-black.
structure
mollusk's body lies in a twisted spiral shell, which has the mouth of the (large hole) and a sharp peak.The shell is covered with the common pond snail hornlike lime greenish-brown substance.It is a reliable protection of its soft body.
The body of the snail is possible to distinguish three main parts: foot, head and body - although there are no sharp boundaries.From across the mouth of the shell can be put out only the front part of the body, leg and head.Foot very muscular.It covers the abdominal part of the body.Such snails known as gastropods.At the same time, sliding on the subjects or the sole of the foot of the suspension to the bottom layer of water, shellfish gently moving forward.
torso while copies shape shell adhering to it very closely.It is covered in front of the mantle (the special fold).The space between her body and called the mantle cavity.The body passes in front of the head, which is located on the underside of his mouth, and two sensitive tentacles - on the sides.The pond with a light touch them instantly draws the sink leg and head.Near the base of the tentacles located on one eye.
Circulation
mollusks common structure is quite interesting.So, he has a heart that pushes the blood into the vessels.At the same time larger vessels are subdivided into smaller ones.And of them have blood goes into the gaps that exist between agencies.Such a system is called "non-closed".Interestingly, the blood washes each of the bodies.Then it is again collected in vessels that lead to the lung, and then is delivered directly to the heart.In such a system to ensure the movement of the blood is much more complicated than in a closed, since it slows down between the bodies.
Breath
Although the snail lives in the water, she was breathing ambient air.For this purpose an ordinary truncatula, the structure of which is described in this article comes up to the surface of a pond at the edge of the sink and opens breathing a round hole.It leads to the lung - a special pocket mantle.The walls of the lung blood vessels densely braided.At this point, there is an allocation of carbon dioxide and enrich the blood with oxygen.
nervous system
This mollusk has peripharyngeal concentration of ganglia.They depart from the nerves to all organs.
Power
snail's mouth leads to the throat.It is covered with teeth, muscular tongue ─ so-called float.Common pond snail, a photo which you can see in this article, it scrapes plaque with all kinds of micro-organisms that are formed in various underwater objects, as well as t different parts of plants.Food is sent from the pharynx to the stomach, and then into the intestine.Also, it helps the liver digest.The intestine opens at the anus into the cavity of the mantle.
Movement
If caught in the pond to land bank, he immediately begins to actively crawl on its walls.From the sink hole at the same time put forward a broad foot, which serves to crawl and head with two long tentacles.Stuck to the sole of the foot a variety of subjects, snail slides forward.This is achieved by sliding wavy, smooth muscle contractions that can be easily observed through the glass vessel.I wonder what an ordinary truncatula can wander through the bottom surface of the water, as we have said above.At the same time it leaves a thin strip of mucus.It stretches across the surface of the water.It is believed that snails moving so using the surface tension of the liquid from the bottom hanging to the elastic film that forms on the surface due to this tension.
This can be easily observed crawling on the calm surface of the pond, going on a trip or a relaxing holiday.
If shellfish truncatula, creeping so under slight pressure again plunge into the water, we will see how he is again like a cork, it rises to the surface.This phenomenon is easily explained: in the respiratory cavity is air.It supports the snail as the swim bladder.Truncatula their respiratory cavity can compress arbitrary.In this case, it becomes harder to clam consequently sinks to the bottom.But with the expansion of the cavity it floats to the surface in a vertical line without whatsoever push.
Try the pond, floating on the water surface, immersed in water and the soft body disturb touch tweezers or chopsticks.Leg immediately retracted back into the sink, but through the breathing hole stand out air bubbles.Next Clam falls to the bottom and is not able to rise to the surface in some other way than zalezaniya plants, because of loss of air float.
Reproduction
Shellfish truncatula is a hermaphrodite, but his cross-fertilization.The snail lays eggs, which are enclosed in a transparent mucous cords attached to the algae.Eggs appear small mollusks with a very thin shell.Contents of the pond
Some aquarists allow content mollusks in a common vessel, not realizing that this is often simply unacceptable.After all, if, say, an apple snail is grown mainly in vitro (in the tank), a snail placed there directly from the pond or small lake of standing water.Mollusks, which have been caught in the wild, are more likely to be a source of infectious diseases and parasites of fish.Very often a young aquarists offer purchase of mollusks in the poultry market and in various pet stores.
If you have decided to still make the pond usual, it is necessary to understand that a prerequisite for its content is considered the water temperature is around 22? C and its moderate hardness.
