The message about the rainwill briefly. Features of the structure of the body of a rainworm. How the digestive, nervous and others are arranged and working. Abstract on the topic for what the rainworms need

Type of ringed worms (Annelides)

Class of maloshetinkovye (OligoChaeta)

Earthworm (Lumbricus Terrestris)

Rainworms - free-lived Organisms. They dwell in the soil, feed on the remains of plants, contribute to the tillage of the soil (Fig. 109).

Fig. 109. Rainworm, his moves in the ground and movement.

The rainworms are elongated (10-15 cm long) rounded in cross section, capable of shrinking and lengthened. The main sign of all ringed worms - round-shaped blundersthat share the body of a rainworm at 100 - 180 segments. On the front third of the body of the rainworm, noticeably small thickening - subtle. On the abdominal and side sides of the body are visible elastic short bristles.

The body of the ringed worms is covered skin-musical bagconsisting of a layer of skin epithelium forming a thin elastic cuticle on the surface, and 2 layers of muscles: ring and longitudinal. Skin epithelium is rich mucous glazed cells. The mucus protects the body from drying and contributes to gas exchange (Fig. 110).

Skin-muscular handwheel bag surrounds with liquid secondary body cavity (whole), wherein

Fig. 110. The structure of the rainworm. BUT - head end; B. - internal structure; IN - nervous system.
1 - oral hole; 2 - Male sexual opening; 3 - female sexual hole; 4 - Rock; 5 - throat; 6 - esophagus; 7 - goiter; 8 -stomach; 9 - intestines; 10 - spinal blood vessel; 11 - ring blood vessels; 12 13 - metanephrium; 14 - ovaries; 15 - semenks; 16 - seed bags; 17 - seeds; 18 - Occollectric nerve knot; 19 - Occillary nervous ring; 20 - abdominal nervous chain; 21 - nerves.
G. - Cross cut of the rainworm.
1 - Cuticula; 2 - epidermis; 3 - Ring muscles 4 - longitudinal muscles; 5 - Hundreds; 6 - whole; 7 - bristles; 8 - metanephrium; 9 - abdominal nervous chain; 10 - abdominal blood vessel; 11 - intestine; 12 - Tiflosol; 13 - spinal blood vessel.

there are internal organs. With the help of transverse partitions, the body cavity is divided into the chambers, the number of which corresponds to the number of outer rings. Cells from which partitions consist are not to the outer or to the inner layer. This is the 3rd (medium) cell layer. He wipes the entire cavity of the rainworm body: covers the skin-muscular bag and organs of the digestive system from the inside.

Fig. 111. Digestive rainworm system.

Digestive system begins rotov Hole located at the front end of the body (Fig. 111). For the mouth goes harness, esophagus, goiter (rear extended part of the esophagus), stomach, middle and rear estate, ending anal hole. 3 pairs fall into the esophagus lime ironserving to neutralize humic acids, which are contained in rotting leaves eaten by worms. The spinal wall of the middle intestine forms the titleosol (longitudinal phenomenon inside the intestinal lumen).

Rainworm has closed circulatory system (Fig. 112). It consists of abdominal and spinal vessels, in the front and rear ends of the body overgoing each other. In each segment of the ring vessel connects the spinal and abdominal vessels. Blood moves due to contractions of spinal and ring vessels. On the spinal vessel blood flows from the back end

Fig. 112. Blood rainworm system.

Fig. 113. Separational system of rainworm.
BUT - scheme; B. - Cross cut.

bodies to the front, and on the abdominal vessel - from the front end to the rear. Blood - red.

Respiratory system At the rainful worm absent. Oxygen enters the body through the entire surface of the skin. It is suitable for numerous capillaries of the circulatory system in which it penetrates. In the tissues, blood is enriched with carbon dioxide, which is then removed through the skin.

Selective system Presented metaphridia. Paired metanephrides (right and left) begin in body cavities voronault. From the funnel leaves khannelinwhich passes through a septum to the next segment and opens outwardly separating sometimes on the abdominal side of the body. The funnel has cilia, helping the movement of the fluid (Fig. 113).

Nervous system comprises occollectric nervous ring and abdominal nervous chain. The nerve ring is formed by the phantorial and subglostic nerve nodes connected by the Commission. On the abdominal side there are two nervous trunks that have nodes in each segment that are connected by jumpers, forming abdominal nervous chain. From all nerve knots in various parts of the worm body, nerves depart (Fig. 114).

Rain Worms - hermaphrodites. Tsemenniki and ovaries are located in the front of the body. Fertilization crossing. When shaking eggs on the worm belt, a heavy mucus is distinguished,

Fig. 114. Nervous system of rainworm.

covering the body of a worm in the form of a coupling. Thanks to the contractions of the muscles, the coupling moves to the head end of the body. Own eggs fall into it first, and then the sperm of another worm. Fertilization occurs. The coupling clenches from the head end of the worm, connects at the ends and turns into a cocoon. After some time, young worms are formed inside the cocoon.

Rain worms are capable of regeneration.

Continuation of table. four

Structure	Head with suckers, neck, proglotids (segments)	Smooth, elongated, narrowed at the ends	Homonic Segmentation - Ring Treasures
Body cover	Skin-muscular bag: 1) skin epithelium; 2) 3 layers of muscles	Skin-muscular bag: 1) cuticle; 2) hypoderma; 3) 1 layer of muscles	Skin-muscular bag: 1) skin epithelium; 2) 2 layers of muscles
Body cavity	Absent. The space between the organs is filled with parenchyma	Primary - pseudocel	Secondary - whole
Digestive system	Absent	Mouth, chuck, esophagus, gut, anal hole	Mouth, throat, esophagus, goiter, stomach, gut, anal hole
Circulatory system	Absent	Absent	Closed
Selective system	Protonefridia	Skin gland	Metanephria
Nervous system	Nervous gangliy on the head, two side trunks passing along the body	Occonditioning nervous ring, abdominal and dorsal nerve trunks	Occonditioning nervous ring, abdominal nervous chain
Sex system	Hermaphrodites	Separations	Hermaphrodites
Cycle of development	Biohylminint: the final owner - a man, intermediate - large cattle	Geohelmint: Host - Man	Free-lived - live in soil

Questions for self-control

1. Where do rigid worms live?
2. What body shape have rain Worms?
3. What covered the body of the rainworm?
4. What body cavity is characteristic of the rainworm?
5. What kind of structure is it digestive system worm?
6. What building has a circulatory worm system?
7. How to breathe a rainworm?
8. What structure has an excretory worm system?
9. What building does the worm nervous system have?
10. What structure has a genital rainworm system?
11. What value does the rainworm have?

Keywords themes "Type of ring worms"

• anal hole
• side Body Wall
• abdominal nervous chain
• abdominal vessel
• internal organs
• funnel
• secondary body cavity
• selection time
• selective system
• hermaphrodites
• pharynx
• rain Worms
• stomach
• liquid
• a vicious circle of blood circulation
• land
• cameras
• khannelin
• capillaries
• oxygen
• intestines
• class
• skin-muscular bag
• cocoon
• round-shaped blunders
• ring vessel
• ring muscles
• killed worms
• commission
• blood
• unobtinka
• metanephria
• pilot nerve knot
• outdoor rings
• unqualified residues
• nervous system
• nervous trunk
• nerves
• occonditioning nervous ring
• fertilization

• respiratory system
• remains of plants
• yays tab
• front end of the body
• nutrients
• digestive system
• esophagus
• surface
• sealing nervous knot
• cross section
• transverse partitions
• the soil
• subtle
• sign
• longitudinal muscles
• balance of soil
• regeneration
• cilia
• retooth hole
• segments
• semencons
• slime
• layer of epithelium
• salivary glands
• spinal vessel
• thickening
• whole
• ovarian

Everyone knows the rainwoods, they constitute a large group of various species belonging to the family of the oligochet.

An ordinary rainwill belongs to the most famous Lumbricidae family, consisting of about 200 species, and about 100 of them are found in our country. The length of the body of an ordinary rainwater worm reaches 30 centimeters.

Types of rainwaves

Depending on the biology of rainwoods, they are divided into 2 types: worms that feed in soil and worms, mining food on the surface of the soil.

To the worms that eat in the soil include underlining worms, living in the layer of bedding and non-depth lower than 10 centimeters even when freezing or drying the soil.

This type also includes soil-bedroom worms, which, under adverse conditions, can penetrate into a depth of 20 centimeters. This also includes chore worms that constantly live at the depth of the 1st meter and more. These worms leave their holes rarely, and in pairing and nutrition, they are torn to the surface only the front part of the body. In addition, this type includes wovers, they spend their lives in deep soil layers.

Roaring and bedding worms live in areas with overwhelmed soils: on the shores of the reservoirs, in swampy locations, in moisture of subtropical zones. The underlying and soil-bedroom worms live in Taiga and Tundra. And soil worms live in the steppes. The most favorite habitat of all types of rainwoods is coniferous and coarse forests.

Lifestyle worms

The rain worms lead a nightlife. At night, they can be found with low-rise in various places.

At the same time, they leave their tails in minks, and the body pulls out and explore the surrounding space, capturing the mouth who fallen leaves and dragging them into the mink. During power, the throat of a rainworm is slightly turned out, and then retracts back.

Rain worm nutrition

Worms are omnivorous. They swallow a large number of Soil and absorb organic substances from it. In the same way, they eat half-chased leaves, except for solid leaves or leaves having an unpleasant smell for worms. If the worms live in pots from the ground, then you can see how they eat fresh leaves of plants.

Darwin explored the worms, he spent great scientific work and during her I made interesting observations. In 1881, Darwin's book "The formation of a vegetable layer of rainwrites" was published. The scientist contained worms in the pots with the Earth and studied how they behave everyday life and eat. For example, to find out what the worms eat in addition to the land and leaves eat, he attached pins pieces of boiled and raw meat and looked at how every night worms were torn the meat, while taking part of pieces. In addition, there were pieces of dead worms, so Darwin concluded that they were cannibals.

Worms are drained to half-chased leaves in minks to a depth of about 6-10 centimeters and they eat them there. The scientist watched how the rainworms grab food. If a piece of stick to a pin to the soil, then the worm will try to drag it underground. Most often they capture small pieces of sheet and tear them. At this moment, the thick chuck is protruding out and creates for upper Lip. Point of support.

If the worm falls across a large flat surface of the sheet, then its strategy is different. He slightly pushes the front rings in the next, as a result of which the front end becomes wider, it acquires a stupid form, and a small pog appears on it. The throat comes forward, it is attached to the surface of the sheet, and then pulls back and expand slightly. As a result of such actions, in the yam in the front of the body, which is attached to the sheet, a vacuum is obtained. That is, the throat performs the function of the piston, and the worm is tightly attached to the surface of the sheet. If the worm give a thin cabbage sheet, then from its reverse side it will be possible to notice the deepening above the worm's head.

The rain worms do not eat the veins of the leaves, they only suck the tender fabrics. They use the leaves not only in food, but also close with their help inlets into their holes. For this, fading flowers, pieces of stems, wool, feathers, paper are also suitable for this. Often, leafy stiff and feathers can be seen from the holes of the rainwrites. To drag the sheet into a mink, the worm of sminets it. The worm tightly folds the leaves to each other and squeezes. Sometimes the worms expand mink holes or make an additional move to gain new leaves. The space between the leaves is filled with wet earth from the intestine worm. So minks are completely blocked. Such closed minks most often come across autumn time before the worm goes to wintering.

Rain worms are laying out the top of the top of the mink, Darwin considered what they were doing so that their bodies did not touch the cold soil. In addition, Darwin learned about the various ways of digging mink. Chervi do it either, swallowing the earth, or spreading it in different directions. If the worm is spreading the soil, then he encourages the narrow end of the body between the soil particles, then inflates, and after it reduces it, due to which the particles of the earth are moving away. That is, it uses the front of the body as a wedge.

If the soil is too dense, then the rainwright is difficult to push the particles, so it changes the tactics of behavior. He swallows the earth, then misses her through himself, immersing, therefore, gradually in the ground, and he grows a bunch of excrement. Rain Cherves can absorb chalk, sand and other substrates that do not have organic matter. This feature helps the worms to dive into the ground with its heightened dryness or during freezing.

The holes of the rain worms are located vertically or slightly deep. From the inside, they are almost always covered with a thin layer of black recycled soil. The worm thumps the land from the intestine and tampering it along the walls of the hole, performing vertical movements. As a result, the lunk is obtained smooth and very strong. The bristles located on the body of the worm are adjacent to the cavity, they create a Point of Support, as a result of which the worm is quickly moving in its Nore. The liner not only makes the walls of the holes more durable, but also protects the body of the worm from obtaining scratches.

Minks that lead down, as a rule, end with an extended chamber. In these chambers, rain worms winter. Some individuals are spent in the winter, while others are wokering among themselves in the ball. Mink worms lined with seeds or small pebbles, resulting in a layer of air and a worm can breathe.

After the rainwill swallows the earth, eating her or roe move, it rises to the surface and throws it. These lumps of land are impregnated with discharge from the intestine, so they are viscous. When lumps dry, they are hardening. Cryships emit land is not chaotic, but in turn in different directions from the entrance to the mink. The tail of the worm uses during this work as a shovel. Thus, a turret from excrement is formed around the entrance to Nouro. All turrets in worms of different species differ in height and form.

The yield of the rain coat

To get out of the hole and throw away the excrement, the worm pulls the tail forward, and if the worm must collect leaves, then he gives off his head out of the ground. That is, in the holes, the rainworms can be turned over.

Rain worms emit land not always near the surface, if they detect the cavity, for example, in spa land or near the roots of trees, they throw away the excrement in this cavity. Between the many stones and under fallen trees, there are small lumps of excrement of rainwrites. Sometimes the worms fill their old holes with excrement.

Life of raindling worms

These small animals played a significant role in the history of education. earth crust. They live in large quantities in wet places. Since the worms are digging the land, it is constantly in motion. As a result, the particles of the soil are shared by each other, new layers of soil fall on the surface, are exposed to humus acids and carbon dioxide, and most mineral substances dissolves. Muscic acids are formed when digesting the worms of semi-disconnected leaves. Rainselkers contribute to increasing potassium and phosphorus in soil. In addition, the land that passed through the intestinal worm is glued with calcite, which is a derivative of calcium carbon dioxide.

The excrement of worms are densely compressed and fall out in the form of durable particles that are not so quickly blurred than ordinary soil lumps of a similar value. These excrement are elements of the grainy structure of the soil. The rain worms every year form a huge number of excrement. During the day, every rainwater worm comes out about 4-5 grams of land, that is, this is the amount of the body weight of the worm itself. Each year, rainworms are thrown into the surface of the ground with a layer of excrement, the thickness of which is 0.5 centimeters. Darwin calculated that 1 hectare pastures of England accounts for up to 4 tons of dry mass. Under Moscow, in the fields of many years of herbs, Chervi form for 1 hectare of the Earth every year 53 tons of excrement.

Cherves prepare the soil for plant growth: soil breaks down, small lumps are obtained, which improves the access of air and penetration of water. In addition, the rainworms are drained to leave the leaves in their holes, partially digesting them and mixing with excrement. Thanks to the activity of worms, the soil is evenly mixed with plant residues, thus, it turns out a fertile mixture.

The roots of plants are easier to propagate in the worms, besides, they contain nutritious humus. It is difficult not to surprise the fact that the entire fertile layer was treated with rainworms, and after a few years, they recycle it again. Darwin believed that no longer had animals that had the same meaning in the history of the formation of the earth's crust, although the worms are low-organized beings.

The activity of rainwrites leads to the fact that the stones and large items over time go deep into the earth, and small fragments of the Earth are gradually digested and turn into the sand. Darwin emphasized that archaeologists should be obliged to worms because they contribute to the preservation of ancient objects. Objects such as gold jewelry, labor guns, coins and other archaeological values \u200b\u200bare gradually buried under the excrement of rainwrites, thanks to which they are reliably saved for future generations, which will remove the covering layer of the Earth.

Damage to rainworms, as well as many other animals, is making developing human activities. The use of pesticides and fertilizers leads to a decrease in the number of worms. To date, there are 11 types of rainworms in the Red Book. People repeatedly moved various types of rainworms in the terrain where they are not enough. The worms were acclimatized, and these attempts were completed. These activities, called zoological amelioration, allow you to preserve the number of rainwrites.

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The rain cerv has an elongated, 10-16 cm long long. In cross section, the body is rounded, but, unlike round worms, it is divided into annular hats per 100-180 segments. Small elastic bristles are sitting on every segment. They are almost not visible, but if they have fingers from the rear end of the body of the worm to the front, then we will immediately feel them. With these bristles, the worm clings when driving behind the nervousness of the soil.

Figure: Rainworm and Worm Movement in Soil

Rainhery Wear

During the day of the worms are kept in the soil by making in it. If the soil is soft, then the worm will boight it with the front end of the body. At the same time, he first compresses the front end of the body, so that he becomes thin, and encourages it forward between the soil lumps. Then the front end thickens, spreading the soil, and the worm pulls the back of the body. In dense soil, the worm can still have a move, passing the land through the intestines. A bunch of land can be seen on the surface of the soil - they are left here worms at night. They also come to the surface after strong rain (Hence the name - rain). In summer, the worms are kept in the surface layers of the soil, and the mink rose to 2 m deep on the winter.

Skin-muscular bag

If you take a worm in hand, we will find that the skin is wet, covered with mucus. This mucus makes it easier to move the worm in the soil. In addition, only the wet skin is penetrating the oxygen into the body necessary for breathing.
Under the skin, the annular muscles have grown with it, and under them a layer of longitudinal muscles - the skin-muscular bag is obtained. The annular muscles make the body with thin and long, and the longitudinal shock and thicken. Thanks to the alternate work of these muscles and the worm movement occurs.

Body cavity of the rainworm

Figure: Internal structure of the rainworm

Under the skin-muscular bag there is a body cavity filled with liquid, in which there are internal organs. This body cavity is not solid, like round worms, but is divided by transverse partitions, respectively, the number of segments. It has its own walls and is located under the skin-muscular bag.

Rainworm Digestion Organs

Figure: Digestive Rain Coast System

Roth is located at the front end of the body. It feeds on a rainworm with rotting plant residues, which he swallows together with the Earth. It can also drag the fallen leaves from the surface. Switching is made with a muscular throat. Then food enters the intestines. Imaginary residues together with the ground are thrown through an anal hole at the rear end of the body.

Figure: Blood Rainhery Worm System

The circulatory system of the rainwood is used to transfer oxygen and nutrients primarily to the muscles. At the rainworm, two main blood vessels: spinal blood vesselon which blood moves from behind in the backward, and abdominal blood vesselThrough which blood flows in front of the back. Both vessels in each segment are connected to olte vessels. Several thick ring vessels have muscle walls, due to the reduction of blood flow. The main vessels departs thinner, branching on the smallest capillaries. These capillaries receive oxygen from the skin and nutrients from the intestine, and from other of the same capillaries, branched in the muscles, there are returns to these substances. Thus, blood moves all the time along the vessels and is not mixed with a strip liquid. Such a blood system is called a closed circulatory system.

Separation system of rainworm

Liquid unnecessary, recycled substances enter the body cavity. In each segment there is a pair of tubes. Each tube at the inner end has a funnel, the recycled unnecessary substances come into it and are output from the tube across the opposite end.

Figure: Nervous Rainhery System

A pair of nervous trunks passes along the entire body of the worm of the abdominal side. In every segment they are developed nervous nodes - It turns out nervous chain. In front of the two large nodes are connected to each other ring jumpers - forms occonditioning nervous ring. Nerves are departed from all nodes to various organs.

Rainhery

There are no special senses, but sensitive cells in the skin allow rainwright to feel touching his skin and distinguish light from darkness.

Sex system and reproduction of the rainworm

Rain worms - hermaphrodites. Before laying eggs, two worms are in contact with some time and exchange seminal liquid - sperm. They then diverge, and from thickening (belt), which is available on the front of the worm, is distinguished by a mucus. Eggs come into this mucus. Then the lump of mucus with eggs slides from the body of the worm and freezes in cocoon. Young worms come out of the cocoon.

1. General comments. Outdoor signs

Let's start with familiarization with the structure of the body of rainwrites. Body Device - the basis of animal knowledge. Would we like to deal with the diversity of the forms of forms of interest to us for some reason, or familiarize themselves with the image of their lives, their connection with their habitat or to approach the solution of certain other practical questionsassociated with these animals, etc. - The question of the structure of the body is the main prerequisite for solving any other. In particular, with regard to raindling worms, already in order to determine the kind and view of any of their representative (and, as we will see, there are a considerable number), there is no need to know its outdoor signs, but it is necessary to establish a number of features by opening it internal organs.

In parallel, we will get acquainted with the work of the described organs and their meaning in the life of worms.

In the body of the rainworm (Fig. 1) you can distinguish the front (or head) end of the body, thicker, with a stronger muscles and is usually darker, and the rear (or tail), thinner and more pale. The rear end of the worm is often flat. At the head end of the body, the mouth is placed on the tail - the posterior hole. Also differ from each other also the dorsal side, more convex and usually darker, and abdominal - brighter and more flat; In worms canned in alcohol or in formalin, the abdominal side can be concave places or along the entire length.

The whole body of the rainworm is divided into transverse patterns into separate sections, which are called segments, or segments. This ripple, or segmentation - the leading trait of their organization: each of the segments in principle has the same structure and contains mainly the entire complex of organs inherent in these animals. In front of the body, segments are larger, in the direction of the stop their size gradually decreases. The number of segments in conventional species varies in the range from 90 to 300; It is subject to significant oscillations from different copies of the same species, but with age, unlike many of their water, does not change. Only in some tropical species The number of segments reaches 600. Carefully look at the body surface, you can see that each segment is divided into three parts with two shallow grooves. This is the so-called secondary rill, which also reflects some features. internal organization Each segment. The bodies segments are numbered, and the first segment is considered the head.

The head segment, in addition to the oral hole, has another one characteristic feature: On the front of it there is a head blade - movable, changing the form of the appendage, hanging over the mouth. In the rainworms, the head segment can be a double kind: either a head blade, going on the spinal side to the region of the first segment, separated from it by a transverse groove, or it comes to a furrow between the 1st and 2nd segments. In the first case, the head segment is called epilobic, in the second - Tanilobic. These differences in the shape of a head blade are important in determining the types of worms (Fig. 2).

Head blade - the tie and smell body; It explores the objects encountered on his way.

In the front of the body in adults there is a so-called belt, that is, the thickening, embracing from 5 to 12 segments, is usually different in comparison with the rest of the body (Fig. 3). Skin covers in the area of \u200b\u200bthe belt contain a large amount of glands that make up the nutrient for eggs when shaking egg cocoons. Therefore, during the period of reproduction, the belt looks highly swollen, and then when there are no cocoons, the area of \u200b\u200bthe belt differs from the neighboring sites only by the color and other character of the body surface. The form of the belt may be ring, if it is developed equally strongly from all sides, or saddle, if it is a little developed from the abdominal side. On the sides of the abdominal side of the belt are the elongated thickening, which we will call rollers of maturity (Fig. 35). In some species, these rollers are replaced by several pairs of maturity tubercles. Form, length, color and location of the belt, rollers and tubercles serve substantial species signs Rain worms.

The entire length of the body of the worm can notice small bristles that are clearly visible in the magnifying glass. They are located on all bodies segments, except for the 1st. In the rainworms of the Fauna of the USSR, the bristles are located 8 on each segment, pairwise or one. The bristles form on each side of the body of the worm of 4 longitudinal series, which are accepted to indicate letters latin alphabet - A, B, C, D (Fig. 4). Their location has great importance When determining worms. Rows of bristles A and B, C and D are usually brought together in pairs. The degree of their rapprochement from different species is different. When determining the worms, the ratio of distances between rows of bristles is also taken into account. These distances are denoted by the letters AA, AB, BC, CD and DD (as it is customary to designate the segments of the lines in geometry). It also matters the ratio of the distance between the bristles to the magnitude of the outer contour of the transverse section through the worm.

Bristles - important organs Movement: The worm can engage them for particles of soil or pushed from them when moving in soil minks and on the surface of the Earth. You can also be convinced of their presence by spending a finger along the body's abdominal side from the tail end to the head. If a living worm is placed on a sheet of paper, then a characteristic rustle will be well heard when it is moved by friction of solid bristles. On some segments of the bristles are modified into special genital bristles that have a value when making worms.

On the abdominal side of the body, the floor openings are placed ahead of the belt. This includes a pair of men's sexual pores, usually located on elevations - the so-called glandular pillows (Fig. 34) and a pair of female sexual pores, outside poorly distinguishable.

In addition, most species have 2-3 pairs of pores of semi-artists. The meaning of all these holes will be told below.

On the dorsal side of canned worms are clearly visible in intersegment grooves, spinal pores, the front limit of the location of which matters when determining the types of worms.

The color of the body of rainwrites depends on the one hand, from the color of their blood, on the other - from the skin pigments. It should be strictly distinguished by the color of the body of the worms, which can only be considered in relation to living individuals and which depends on the combination of skin pigment and blood color, from the pigmentation of the skin, which is due only to the presence of pigments. Worms, devoid of pigment, have a pink or red color of the body in a canned state, and in canned state become white or grayish, the pigmented species can be red, brown, brown, yellow and blue tones.

The length of the body of the rainworms of the USSR ranges from 2 to 30 cm with a thickness of 2 to 12. We. In tropical countries there are species reaching a length of 3 m. The main mass of worms that inhabit soils around the world are represented by species having a length of 5-20 cm.

All further presentation refers to the rainworms of the Lumbricidae family. Worms of other families (except for botanical gardens where worms are sometimes recorded together with tropical plants) can meet only in the Ussuri Territory, Central Asia and in the southern part Black Sea coast Caucasus.

2. Body cover

The body of the rainworms is covered with a single-layer epithelium. Its composition has supporting, ferrous and cambial cells (Fig. 5).

Supporting cells are provided by a protective function. The outer part of these cells highlights the cutyonic substance - a thin transparent film covering the epithelium. The cuticle consists of two parallel fiber systems intersecting with each other at right angles. In the crossing places in the cuticle there may be holes. The direction of fibers is diagonal in relation to the longitudinal axis of the body (Fig. 6), which in the best way ensures the strength of the cuticle when stretching from the inside (it is curious that the connective tissue fibers in the mammalian skin also have a diagonal location with respect to the longitudinal axis of the body). The cuticle throughout the life all the time is sheltered and renewed by the activities of the epithelium. Canned instances of the cuticle can fall behind, and sometimes it can be removed entirely as stocking.

The cuticle is due to the smoothness of the skin surface, which facilitates the gliding of the body when driving along solid surfaces. It also causes the characteristic glossiness of the body surface.

The activities of fervent cells are of great importance in the life of worms. Most of They allocate the mucous membrane, which always lubricates the surface of the cuticle; It goes to the surface of the body through the holes in it (Fig. 5 and 6). This increases the ease of sliding on the substrate and protects the body from drying. With any strong irritation The mucous membrands protrude to the surface of the body in huge quantities: the worm is instantly enveloped by a thick layer of thick adhesive mucus. The formation of the mucous membol on the body plays important role When pairing and the formation of egg cocoons. In addition, the mucous allocations cover the walls of the worms inside the soil, which gives them considerable strength.

In addition to conventional mucous cells, in the skin epithelium of rainworms, there are so-called protein glandular cells on the entire body surface (Fig. 5). In the area of \u200b\u200bthe belt (Fig. 25), near the bristles of the genital holes and in other places of the body are skin glands, the value of which will be mentioned below.

An important component of the skin epithelium is small cells that are in its deep part, on the border with a diverse to be muscular, and not contact with the outer parts of supporting and gland cells (Fig. 5). These are Cambial Cells, which are reserve; Due to them, broken functioning cells are resumed and tissue growth occurs in young animals. These cells are also mobilized when healing wounds after injuries and other damage.

From special cells of the skin epithelium, bristles are also formed. On the surface of the body only the outer part of the bristles. It is deeply immersed in the wall of the body and can permeate it through, almost reaching the body cavity. The bristles are placed in bristle bags, which are rustling inside the body of the skin epithelium (Fig. 7). They consist of a substance that is similar to the substance of the cuticle, are fragile and quickly wear. Therefore, throughout the life in the depths of the bristle bags, the formation of new bristles. Each bristle is formed from one cell, which is part of the bottom of the bristle bag.

The bristles of raindling worms are no-form, but shape: these are sticks, sometimes almost quite straight, sometimes with clearly curved ends. At some distance from the outer end of the bristles there is a small thickening - nodules, i.e. the place to which the muscles are attached, pulling the bristle into the depths of the body (muscles of retractors; Fig. 7). In addition to them, in the bristle bags there are muscle protesters, which are attached by one end to the end of the bristles, and to the other - to the wall of the body; Their reduction of the bristles is ejected outward, as well as (with non-violent reduction) can make quite a variety of movements.

For genital bristles, see below (p. 54).

Speaking about the cover of the body, we mention about interesting phenomenon The glow of rainworms, which for a long time attracted the attention of many large naturalists. In particular, the famous explorer of life insects wrote about the luminous rainwirs - Fabre. IN different countries Describes special species "Phosphoric" worms. It turned out however, that the glow in the dark can be observed at the most ordinary species. The famous Czech researcher Vadidovsky said that, sheepdowning one night a dung bunch in search of rainworms, he saw the stains of shimmering bluetic white light, which appeared, then disappeared into different points. It turned out that the light proceeded from ordinary man-off striped worms, which he collected in large quantities. He noticed that his fingers after he took the worms, began to glow in the dark. Thus, the mucous membranes of worms are shining, and only if there are special conditions, since the glow is not always observed. There are indications of the luminescence of the fluid serving from the oral and rear-ground holes.

There can be no doubt that in all these cases the glow is caused by bacteria contained in the sewages of worms. In the course of vital activity of many bacteria, light energy is distinguished, freed during chemical reactions. It must be said that almost always the glow of animals is required by their origin bacteria, one way or another associated with it.

Some researchers believe that the glow is useful for worms: Some people think that the flashes of light contribute to finding each other's individuals on the surface of the earth during mating (although the worms and there are no eyes, they are still capable of perceiving the light of the surface of the front of the body); Others are attributed to the glow role of a factor that scares enemies; Third think that the luminous mucus left by the worms on their way attracts the attention of enemies and makes them less noticeable. However, all this is nothing more than assumptions, not supported by accurate observations.

3. Musculature and movement. Body cavity

The main part of the rainwriting motor apparatus is the powerful muscles of their body wall (Fig. 8). It is arranged but the type of so-called skin-muscular bag. Under the skin epithelium, there is a layer of ring muscles, the reduction of which reduces the diameter of the worm. The ring musculature layer is littered with a layer of longitudinal muscles (Fig. 18), the reduction of which reduces the length of the worm. On the border between these two layers there is a very thin layer of diagonal muscular fibers..

On most of the body, the longitudinal layer of muscles has significantly greater power than the ring, but in the front 8-12 segments of the body of the ring layer can reach the thickness of the longitudinal layer. These segments play a particularly important role when driving a worm in the ground (Fig. 9).

Previously thought that the moves of the worms in the ground are formed by the absorption of them of the earth, that is, that the worm is eaten into the ground. However, as Darwin has already shown, these moves are mainly the result of active muscular work, due to which the particles of even very solid soils can be spread. Powging of the soil during digging can certainly occur, but it has a secondary meaning. Close-up of rainwrites in order to scream into a dense soil for the entire length of the body, 30-40 minutes are enough. This ability to make moves in the ground, allowing the rainworms to penetrate deep into the ground, sometimes on a depth of 2 m or more, largely and determines the space role of rainwood as the soilorage. To do this, you need a great power of musculature, which they possess. The muscles of the body wall is 38-44% of the body volume, and in the most powerful species, this figure rises to 50%. In this regard, worms from invertebrates are inferior only to leeches, whose body muscles can be up to 65% of the body volume.

On the surface of the Earth and inside the finished underground strokes, the worm, as well as when injected, moves by naturally alternating cuts of the longitudinal and ring muscles combined with the movement of the bristles (peristaltic movements). In the calm state of the worms move rather slowly, but with strong irritations they can be very quickly reduced, even something like jumps, especially when you have to escape from persecution. In these movements, the longitudinal muscles, promoting the speed of the translational movement, becomes a special role. Cherves can quickly move up in vertical moves made by them in the ground. Experiments in glass tubes with types of giving births to Lumbricus and Allolobophora have shown that worms are based on the spinal surface of the body to a solid surface of the tube. In addition, the movement of the worm helps the mouth acting as a suction cup (Japp, 1956).

This is justified not only the incomparably large thickness of the longitudinal muscles compared to the annular layer, but also the features of its structure. In many species in longitudinal muscles, there is a peculiar order of the arrangement of muscle fibers. The latter are fortified connective tissue Parallel rows, so that on the cross section they seem compiled in the "Christmas tree". This arrangement of musculature fibers is called Pirish. It is not observed in all types; Many species are typical, the beam location of the longitudinal muscles fibers.

For the effectiveness of the muscles, the fact that under the body of the body is a cavity filled with liquid. This cavity is similar by origin and nature with the abdominal cavity of the highest vertebrate and man, i.e., just like them, the insides are placed in it and it is lined with a flat epithelium that is called "peritoneal". In the worms, the body cavity is divided according to the segments of the body by integmentation partitions. In addition, the body cavity is divided into the right and left side by a mesentery connecting the abdominal side of the body with a bowel. In general, the body of the worm is as if two tubes embedded one to another: the wall of the outer tube is the wall of the body, the wall of the internal intestine. The gap between them is occupied by the body cavity filled with liquid. All fluids are known to be very elastic and practically incompressible at arbitrarily large pressures. Therefore, the strip liquid is an antagonist of musculature and to a certain extent replaces the worm of the missing skeleton. When the muscles of the body wall is reduced, the pressure on it from the inside from the side of the strip fluid (TPGOP) increases, and, due to its incomprehensibility, the surface of the worm acquires the properties of an elastic solid. It helps him when driving, and especially when digging underground moves; The front end of the body of the worm will take into the soil like a solid wedge.

We mention again that with the movements of the raindling worms, the combined effect of the body wall of the body and bristles has a combined effect. Special meaning The work of the bristles (except for vacuuming to the ground) acquires when lazaping in the steepness. It is known that many types of worms can fit on the trees that they are found in large barrels set for the collection of rainwater, or in mature coams of cabbage under the outer leaves, or in the middle of the corn, etc.

4. Intestine and food

The mouth, located at the front end of the body, leads into a small oral cavity with folded walls, followed by a muscular throat (Fig. 10). Due to the fact that the throat is connected by the complex binding of muscle fibers with the body wall, it not only performs swallowing movements and presses ingestion substances, but can also be turned out through wide open mouth. These movements allow the capture of such objects as leaves, pebbles, etc., used for nutrition or for other purposes. In the thickness of the pharyngeal wall and beyond the numerous pharynges, which are opened directly into the throat or into a special pocket in the spine thickened part of the wall. Plug glands allocate mucous membranes, enveloping dusting food particles. In this regard, their activities are similar to the activities salivary glands other animals. But, in addition, the prying glands produce a substance, digesting proteins; It is actively in an alkaline medium and similar in its action with an enzyme entering the bowel from the pancreas in vertebrates. Thus, the chemical treatment of proteins begins in the rainworms already in the oral cavity, which is probably due to the need to make it possible to more complete the extraction of protein substances from food, as a rule, exclusively by poor these substances.

The throat goes into the esophagus (Fig. 10). This is a rather narrow cylindrical tube, the walls of which are well developed muscles. On the sides of the esophagus there are 1-3 pairs of side pockets (Fig. 10) - the so-called lime glands. In some species, they are located in the thickness of the wall of the esophagus and because they are unnoticed outside. These glands are called lime due to the fact that in them under the microscope find crystals of carbon dioxide. That these glands produce lime - it is proved by the fact of a significant enrichment of foods by it during passing them through the intestines (the number of carbon dioxide in the content of the intestine can increase from 0.8 to 1.3-1.8%). It was assumed that the role of these glands is to neutralize the acids contained in the soil swallowable. This assumption is in good agreement with the above-mentioned need for an alkaline environment for the activities of digestive enzymes. However, it is unlikely that it is exhausted by the role of the lime glands. Regarding their functions there are many other assumptions, with the most diverse; Already it shows that the function of the limestone has to be considered an unexplained.

Behind the esophagus is the bulk extension of the intestinal tube - the so-called goiter (Fig. 10), which occupies 2-3 segments. It accumulates stigma food, which from there portions enters the following intestinal deposits. In the absence of such adaptation, the body did not have time to cope with the processing of the incoming material. Goz has quite thin elastic walls, so it is well stretched.

Immediately behind the goiter is another extension of the intestinal tube - the muscular stomach. Inside, it was lined with epithelium with a thick cuticle, and its wall consists of ring and longitudinal layers of muscles, and the internal, ring layer is particularly strongly developed, which has a "perisite" structure, like a longitudinal layer of musculature of the body wall. The task of the stomach is the rubbing of food; In this process main role plays, as well as chickens and other graining birds, friction on each other of the soil mineral particles, between which are organic food substances. Darwin watched that the grains and pieces of bricks who passed through the intestines of the rainworms are taken instead of an angular intavy form. There are new observations and experiments, proving the importance of soil mineral particles for food in the intestine of worms; In their absence (for example, if you put the worms in the peat) they are starving, despite the abundant feed in the form of leaves (Zrazhevsky, 1953).

The muscle stomach follows the middle intestine that goes to the rear end of the body.

At the entire length of the middle intestine, a deep spinal fold stretches, or a typhlosol, due to which the caustic outlines take on transverse cuts (Fig. 11) on transverse cuts. The physiological significance of this peculiar feature of the intestinal organization is clear: in this way an increase in the suction surface of the intestine is achieved. The intestinal wall contains a large number of iron cells that produce mucous secrets and digestive enzymes. Among the latter, as in the throat, there are enzymes, digesting proteins, and, moreover, enzymes that turn starch in sugar (maltose and glucose); In the intestine, the conversion of fats in the soluble state. Thus, in worms, as in vertebrates, nutrients in the form of solutions are absorbed by the intestinal wall. The advancement of food is performed by the action of the intestine muscles, which consists of an internal annular and outer longitudinal layers of muscles (it should be paid to the fact that the location of the layers here is the opposite one in the body wall). Some species have several layers of muscles in the intestinal wall.

On the last 10-15 bodies segments, the intestine is deprived of a spinal fold, and his epithelium acquires cilia. This part is called the rear intestine. Suction in it no longer happens, but only the process of formation of lumps of feces, i.e., those coproins that have so important for the soil structure. On the last segment of the body, the intestine opens out the outward-in-step hole having a type of vertical gap.

Interesting the dispute of the two famous Naturalists of the last century on the issue of the food worms - Etienne Klapareda (France), an excellent connoisseur of invertebrates (in particular, ringed worms), and Charles Darwin (England). Klapared found in different parts of the intestine of the rainwords of the remnants of crushed leaves mixed with the Earth, and on this basis it believed that the Earth worms swallow only with the goal so that the laying herbal residues would be better ended with them. Darwin, not denying the fact that the worms feed on fallen leaves and other plant residues, at the same time argued that both the lands are used by them for nutrition. He watched that were abundantly populated by worms and those places where they can eat only the ground rich organic substances (for example, neatly sweeping yards). All further studies have confirmed the correctness of the observations of Darwin.

The question of the ability of worms to choose your meal, we will be touched in the future when we talk about the functions of their nervous system and senses.

Of great importance is the amount of earth worms being processed in the intestine. It turned out to be huge: weighing coprolytes found that worms that inhabit cultural soils are passed through the intestines for 24 hours the amount of soil equal to the weight of their body.

In order to complete the intestinal consideration, we mention about the characteristic tissue taking out the entire average of the middle intestine and the spine blood vessel and the replenish spinal fold of the intestine. When opening a living or just a dead rainwater worm attracts the attention of the yellow color and the loose velvety surface of the middle intestine, on which red blood vessels are contrasting. This fabric is called chlorogenic, or yellow. Its connection with the intestines purely topographic: it is a modified part of the cavity cavity (peritoneal epithelium) adjacent to the intestines. The yellow tissue consists of large cells whose plasma is filled with drops of substances having a yellowish color. The origin and nature of this substance, and at the same time the function of the tissue itself is not quite clear. Some researchers consider this tissue by the place of accumulation of spare nutritious materials, like vertebral adipose tissue. Indeed, the inclusion of yellow tissue cells contain fat, protein and a substance similar to glycogen (animal starch). At the same time, it is known that this tissue contains a large amount of uric acid that foreign substances introduced in the form of solutions in the body cavity (paint) accumulate in cells of chlorogenic tissue and that final nitrogenous metabolic products to be removed from the body usually have Yellow or brown color. All this makes thinking about the excretory function of this tissue. It is very likely that, along with the accumulation of spare nutrients, the cells of yellow tissue have the ability to extract blood and fluid from circulating in it, which fills the body cavity, the garbage generated during the metabolism process. Finding inside the cells of yellow tissue, these substances are turned off from the blood current and are made harmless. Gradually accumulating in the cells of this tissue, they can remain there for a long time, but can be released from the body, since the cells of the yellow tissue are often reversed and fall into the body cavity, and from there are outwarded together with a combination of a strip fluid through the spine.

5. Blood system. Features of nutrients and oxygen distribution

The distribution of nutrients used by the surface of the intestine is carried out in the rain worms with the help of a highly developed circulatory system. The layout of the main vessels is the following (Fig. 8, 10 and 12). Along the entire body pass the dorsal (over the intestines) and the abdominal (under the intestines) of the vessels. The spinal vessel is equipped with a muscles, which drives blood from the rear end of the body to the front. In several front segments (from the 7th to 11th or, in other species, from the 7th to the 13th), the spinal vessel is reported to 5-7 pairs of transverse vessels with an abdominal vessel. These vessels are equipped with a particularly strong muscles of n called hearts. They fully justify this name, as they serve as the main apparatus providing blood circulation. The blood coming from the hearts in the abdominal vessel moves towards the rear end of the body. On the way, it enters the vessels that feed the wall of the body ", as well as in the vessels going to the intestines, to the excretory organs (Fig. 13), and in the corresponding segments and to the genital organs. In all these parts of the body, the vessels are disintegrated into a network of microscopic capillaries. From the capillaries, the blood enters into transverse vessels, which are ultimately bonded from the whole body in the spinal vessel.

There are other longitudinal and transverse vessels that can be seen in Fig. 8, 10, 12 and 13; We will not stop on them. Of particular importance is the thick weeliness of small vessels around the intestine (Fig. 13). This comes the nutrients seeded by the intestine, and from here they are spread throughout the body. Note that the muscles, although not so much developed as in the spinal vessel and hearts, have almost all vessels, which prevents the possibility of blood stys in the peripheral parts of the circulatory system.

The blood of the rain worms, as already noted, red. This color is due to the presence of a substance that is very close to the hemoglobin of blood vertebrates. However, the worms are not contained in blood calves, but dissolved in the liquid part of the blood (blood plasma). On earthworms there are only colorless cells of several types in the blood, in general the same as the tines of colorless blood cells in vertebrates.

As is known, hemoglobin in vertebrates provides oxygen transportation from respiratory organs to all living body cells. The same role plays a substance similar to hemoglobin, and in the rain worms. However, they do not have special respiratory organs: they breathe the entire surface of the body. Thin cuticle and tenderness of the skin of rainwoods, as well as a rich skin net blood vessels, well provide the possibility of absorbing oxygen from ambient. But we note that the cuticle of rainworms is well wetted with water and oxygen, apparently, they must first dissolve in water, wetting skin Covers. It entails the need to save skin in a wet state. This one makes it clear how important for the life of the worms are the conditions of the moisture of the external environment. With skin drying, breathing is made impossible for them. However, in case of contact and conditions, the lack of moisture in the soil worm may long fight this, using water reserves available inside the body. In these cases, skin glands come to help (see page 15), and in the case of an acute lack of moisture, it utilizes a strip fluid that spinning it from the spine.

The absorption of oxygen with the surface of the body is facilitated by the presence of a very rich network of blood capillaries penetrating even into the skin epithelium (Fig. 14) hence the blood through the vessels of the body wall and transverse vessels falls into the main trunks of the blood stream, which is achieved by the supply of whole body. The red color of the painting of most types of rainwrites (not pigmentation, see page 15) are determined precisely, the presence of a rich network of skin blood vessels.

All this creates the ability to live worms in a very low oxygen content. In this regard, they are approaching some of their remote freshwater rods - tubes (Tubifex Tubifex, Limnodrilus Hoffmeister, etc.), which, upheld in deep il, can take out the absence of an almost oxygen. Relatively rainworms have observations that they can live in the content of oxygen in the surrounding airspace, equal to 2.5% (as is known, it is usually contained in the air 21%). Even with the presence of 0.4% oxygen in the air, the worms can absorb half the amount of oxygen necessary to them for maintaining life, and may be in these conditions for quite a while. In addition, hitting in an oxygenous medium, worms can switch to a special type of metabolism in which the energy source for life processes is not an oxidation reaction (for which oxygen is needed), and the decay of the starch-like substance is glycogen, which is performed in an oxygen-free medium. However, the reserves of glycogen in the worms are not particularly large, and, in addition, the method of metabolism is distinguished by acids harmful to the worms acting on the body.

Being under water, worms are just as well can absorb oxygen as in air. It is known that they can live in water for months in the presence of the minimum of the oxygen and the other conditions necessary for them. This fact is of great importance for understanding many phenomena from the life of rainworms.

6. Allocation bodies. Top absorption and release

The selection function is performed in the rainworms (like all rings) tubular organs located in pairs in each segment, except the most front. These organs are called nephonds, which means in a Greek "organ like a kidney." Nephonds are located in the body cavity on the sides of the intestine (Fig. 8 and 12). Each of them is an argument tube starting inside the body with a hole in the body cavity located on the head expansion whose cells are equipped with cilia. This extension is called by analogy with similar formations in more primitive rings with reservoirs (Fig. 15). Almost directly behind the tubing nephridium, the integrator partition will penetrate and penetrate the next body segment. There, he first forms a strongly reprehensive thin tube, which goes into a wider middle part of nephrium, equipped with cilia. Then nephond, making several loops, goes into the output part, which ends on the abdominal side of the body with an outer hole (Fig. 15), or nephridal sometimes. Outside it is very difficult to find, since it is always tightly closed. Not far from nephridial pore there is an expansion of a nephond tube, which is something like a bladder. Nephonds are equipped rich Network Blood vessels. The blood coming out of nephridia enters the transverse, and from it in the spinal vessel (Fig. 16).

It should be noted that one of the rainwoods (ALLOBOPHORA AntiPae) nephridial tubes are not open independent of each other, and their outer parts fall into the longitudinal excretory channels that pass to the right and on the left of the entire body and in the back end fall into the intestine. from the anal hole. Thus, the compound of the excretory apparatus in one anatomical integer is planned and the connection with the rear intestinal sector is established.

The cells of the fine part of the nephardial tube are captured from the blood circulating outside the network of nephridial capillaries, nitrogen exchange products to be removed from the body. These substances fall into the cavity of the nephond tube and are mixed here with a strip liquid coming through the funnel at the inner end of jade. The bandwidth liquid also contains products of selection, dead cells, there are broken bristles and so on. The liquid of the nephond tube with the bias of the cilia is chasing towards the output end, from where it is periodically thrown out through an outdoor time to reduce body wall musculature (Roots, 1955).

There is evidence that the emptying of the nephrium end bubble occurs once every three days. Other observations suggest that the worm of the worm in 1. -1.8 g allocates 0.82 cm3 excreta. Such quantities should be released from the body several times a day. The excrete contains in general the same substances as in mammals, namely: urea, ammonia, creatinine, salt, etc., but in significantly lower concentrations. However, the normal excret on the worms contains 0.3% protein, while the highest animal proteins in the selection products are missing.

The cells of the middle part of the nephond tube have the ability to phagocytosis, i.e., to active swallowing from the cavity of the body insoluble in water (measurement cells, rolled protein, bacteria, etc.). These substances accumulate there indefinitely for a long time. The sanitary service of this kind is also carried by other cells inside the body: amoeboid blood cells, body cavity cells and the aforementioned cells of chlorogenic, or yellow tissue (see page 26). Especially a lot of amoeboid cells, increasing foreign Taurus, occurs in the body cavity. Here they fall, actively crawling out of the vessels, squeaking between the cells of the vascular wall. These cells are removed from the body cavity different paths. First, they are crawling through the intestinal wall and, falling into its cavity, are outwarded with the feces (it was observed many times); Secondly, as already mentioned, they can be leaving through jade and, thirdly, they can exit together with a strip fluid sprayed through the spine. In general, it is possible to think that the stripe fluid is quite quickly replaced. Therefore, it acquires such great importance from worms during the selection process. The role of her in the life of worms will become clearer after familiarizing water regime their bodies.

We have already pointed to the value of water in the body of worms, when they talked about the role of a strip liquid (98.8% of its composition - water) with muscle work and about the need to moisturize the skin for breathing (p. 30). Water into the body of the worms is continuously incorporated and displayed back to the outer medium specified above the paths. Thus, the body of the worm and, in particular, the body cavity is all the time are riveted with water. Therefore, for the normal implementation of these physiological functions, the worms are needed environmental conditions that would ensure the flow of water into their body in much larger quantities than most of the ground animals.

How does the water enters the body of the worms?

Note above all that worms never drink. They absorb water with the entire surface of the body; Water passes through the covers and muscles, accumulating in the body cavity. At the same time, worms can only use water in liquid state. The worm in a medium containing water pairs can die from drying if it does not have a different source of moisture.

Under normal conditions, the body of worms contains about 84% water. Despite such a significant stock of water, it turns out to be far from the limit. If the worm provide an opportunity to further increase the supply of water in your body, he will immediately do it. This is easy to make sure if you put rainworms in the courtyard. After a few hours, their weight will increase by 10-12% due to the water, the seasanic surface of the body. After removal from the water, the worm returns to the starting weight, and this happens for very short term (1-2 hours). The removal of excess water from the body occurs very peculiar way: it is absorbed by the cells of the intestine, of which it enters the cavity of the latter and is removed mainly through the posterior hole, and partly through the mouth.

Under normal conditions in the soil, the function of removal of excess water lies on nephonds. The presence of a direct current is submensally through the body by sucking it the surface of the body and the release of it in excess kidneys - the phenomenon is very common among the aquatic animals. It is undoubtedly inherited by rainworms from their aqueous ancestors.

The metabolism of aqueous animals is performed with enhanced circulation of water through their body; They cannot threaten the lack of water, whereas in the soil conditions with such a type of water exchange, a sufficient amount of moisture is made by the main factor ensuring the possibility of existence. Therefore, the conditions of soil moisture are important in the question of the population of their or other types of raindrops.

On the ability of rainwoods to lose water during periods of drought and wintering, which is associated with the transition to them to the state of hidden life, see Next (p. 105).

7. The nervous system and organs of feelings. Reflexes

Along midline The abdominal side of the body in the rain worms under muscularly the nervous trunk is stretched, called the abdominal nervous chain. In each body segment there is a nervous knot, or gangulia, which is a cluster of nerve cells and deriving 3 pairs of nerves. Ganglia is connected to each other jumpers, connectives, which, besides nervous fibers, also contain nerve cells. In the front end of the body, in the 3rd segment, the abdominal nerve chain is divided into the right and left pharyngeal connotations, forming a window-discovery nerve ring, connecting with the headlift, or head gangle (Fig. 17). This gangulia is a pair, consists of the right and left half, tightly connected to each other. But unlike all other nerve nodes lying on the abdominal side of the body under the intestine, this gangulia is on the spinal side of the body and lies on the intestine. This ganglion can be opposed to everyone else and due to the fact that it is morphologically comparable to the brain of higher forms (arthropod). Numerous nerve trunks come forward from it, abundantly branched and forming dense nerve plexuses in the first three segments. Under the throat, at the point of discrepancies of the Prying Convention, there is a stilt Gangliya, which is the result of the merger of several ganglia abdominal nervous chain.

As can be seen on cross-cuts, the nerve cells lie along the periphery of the Ganglia, and its average part is occupied by the plexus of the processes of nerve cells (Fig. 18). In the abdominal nervous chain, three very thick fibers, running through the entire length of the worm body under the connective tissue capsule of the nervous chain on its spinal side. These are the so-called Neurochords, which are still quite recently taken for gigantic nerve fibers. However, it is now completely found that they are peculiar supporting formations (nemavak, 19476). These formations and in structure, and function, and on the position between the nervous system and the intestines are similar to the humorous vertebrates.

The nerves, departing from the ganglia of the abdominal chain, contain motor fibers ending with muscles and sensitive, for which irritations come into the nervous system from the periphery. The bodies of sensitive nerve cells are on the periphery, including in the outer epithelium (Fig. 18). Nervous cells here stand in a number of epithelial cells. This extremely ancient type of ratios of the elements of the nervous system has been preserved in the rain worms from their distant ancestors, primitive multicellular animals. It is very interesting that not only the cells of the exterior epithelium are becoming sensitive nerve cells, but, as recently installed, also intestinal cells originating from an internal germinal sheet (neumma, 1947a).

Sensitive nerve cells and their endings are available in other places of the body. They are also richly equipped with nephond, bristle bags and other organs. Thus, in rainworms, as in the highest animals, the operation of the internal organs flows under the control of the regulatory and centralizing role of the nervous system.

From the reflexes of the rain worms are best known observable in the act of crawling. When the worm moves along the entire length of the body, from the front end to the rear, peristaltic waves of combined muscles cuts run. They follow each other, and each next wave may arise long before the first reach the rear end of the body. It would seem obvious, by analogy with the highest animals, that the reason for these waves of abbreviations is the consistent transmission of irritations along the abdominal nervous chain. However, to the surprise of researchers, it turned out that the cut of the abdominal nerve trunk and even cutting out of several nerve nodes do not stop the rubber waves of muscles cutting: the cutting wave passes through the place of damage in the same way as the normal worm. With the same result, you can, in addition to the breaking of the abdominal nervous chain, remove the muscles of several segments or damage it with acid.

The analysis of these and similar experiments showed that the translational movement of the worm is a long chain of reflex acts in which each segment is largely an autonomous physiological unit. Irritation from the periphery leads to a reduction in the muscles of this segment. Due to this reduction, peripheral devices are irritated in the neighboring segment, which cause both abbreviations in it, etc. Thus, the combined muscle contractions in each segment may be an independent reflex, starting with the excitation of sensitive cells on the periphery and the ending effect of the muscles of this segment. . This is the most primitive type of reaction to external influences. Some complication is the transfer of the resulting irritation on the nervous chain into the nearby rear segment of the body, in response to which the muscles of this segment is reduced. In fig. 19 shows a reflex scheme with arcuate flaming worm, when a wave of musculature cuts is on one side of the body. This reflex is the main in the implementation of the translational movement of the worm forward. This method of transmitting irritation by body, as described above, speaks of a weak centralization of its nervous system.

There are also experiments with the removal of the headlift ganglia. It is noted above that morphologically pumping gangli can be compared with the brain of higher forms (arthropod). Many marine rings have a rather complicated device. However, the terrestrial worms have a supervision of gangliy, and the physiological role is very small. After removal of the headlift Ganglia, it is possible to note only some general relaxation of the muscles of the front body of the body, changes in the perception of light; Perhaps he plays a role in reproduction. But in the movements of the worm of significant changes after the wound healing, it fails: the worm also breaks into the ground, also avoids danger and performs all those rather complex reflex reactions with which we will read further. It is especially surprising that the ability to "learn", i.e., according to modern terminology, to conditional reflexes, in worms, deprived of the headlift ganglium, does not disappear.

Sealing gangulia is somewhat greater value, since after its removal, the worm is deprived of many abilities inherent in it: his taste is very affected (p. 45).

It would be mistaken to think that the weak centralization of the nervous system and the relative autonomy of individual segments detected by progressive movement Worm, mean the absence of organism reactions as a whole. It can be said in advance that such reactions may not be, and, indeed, they are very easy to detect. With weak irritation of the rear end of the body (with an easy touch), the worm crawls forward, when irritating in front, it is quickly all shrinking and crawling in the other direction, with strong irritation anywhere, the worm begins to declineally arcuately, in different areas (so-called gymnastic movements); Worms detect rapid reactions to light, odors, etc. Thus, the above-mentioned imperfection of the nervous system and its weak centralization are detected only with attentive observation and in specially supplied experiments.

So, we know that the worm has a rather rich arsenal opportunity for the implementation of certain reactions to changes occurring in their environment.

Let us now consider how it can recognize these changes. Means for this are the senses.

As already mentioned, the entire surface of the worm body is covered with a huge number of sensitive nerve cells. These cells serve as the conname bodies developed by the worms very much. It is known that enough, carefully approaching, weakly blow on the worm so that he will respond with a sharp reduction in the longitudinal muscles; With this movement, it hides in the mink. In addition to sensitive nerve cells in the outer epithelium between the cells there are a very large number of free nerve endings, which, most likely, also provide a touch function.

As you know more than a hundred years ago, the rainworms, despite the lack of eyes, are well perceived by the light. The perception of light is performed by special photosensitive cells, which for the most part are located one by one between the cells of the outer epithelium (Fig. 20). Inside of these cells, in addition to the nucleus and thick network of the thinnest fiber - neurofibrils, there is a transparent light-timing vents of a beanoid or extended shape; It is called a lens by analogy with a crystal eye of higher organized animals. From the body of the cell, a nervous process, entering into subcutaneous nervous plexus and binding it with the central nervous system. Such a cell is undoubtedly represents the simplest eye, as if an isolated and autonomous cell of the retinal eye of higher animals. Photosensitive cells are focused mainly in the front segments of the body; Most of all in the head blade, where there may be over 50 (Fig. 21). In subsequent segments, their number quickly decreases, they do not find them in the middle of the body, and in the last three segments they are becoming more. In some types of rainwoods, in addition to isolated photosensitive cells in the outer epithelium, there are large groups of photosensitive cells located under the skin along the nerves, especially in the head blade (Fig. 22).

Darwin carefully examined the perception of light with rainworms. He found that if you carefully illuminate them with a silent lantern, having only a narrow beam of light, the intensity of which is reduced by red or blue glass (the glass of glass is indifferent), then only very few worms react, namely: go to their holes. Darwin led to observation of those species that at night go out of the holes in search of food or for mating; This is a big red worm (Lumbricus Terrestris), long worm (ALLOBOPHORA LONGA) and some others. The revenge of them usually remains in mink. With stronger lighting (especially accurate results were obtained at the concentration of light rays using a magnifying glass) worms, quickly reducing the longitudinal muscles, hidden in minks, "like rabbits", notes Darwin, leading to an expression of one of his buddies, who watched his experiments. At the same time, Darwin proved that the worms react precisely on the light, and not on the radiant warmth emanating from the light source. Experiments with an approach to the worms of rolled pieces of iron showed that they are little sensitive to radiant warmth. However, when the worms are "busy", that is, when they stick the leaves into their holes, eat, etc., they do not notice the light, even when the light concentrated on them with a large incendiary glass. They do not react to the light they are during mating. In the future, it was proved that very weak light can attract worms, as they move in the direction of its source.

The ability to feel the light plays a very large role in the life of worms, since the sunlight on them is destructive (worms are very sensitive to the ultraviolet part of the solar spectrum). The abnormal care response saves them life (Smith, 1902).

Special hearing organs in worms are not. On very strong sounds transmitted by air, worms do not respond if it does not vibrate a solid substrate with which they have contact. But the trembling of solids, with which they are connected, caused by sounds, they perceive very thin. For example, the observations of Darwin, "When the pot, which made a couple of worms, who were completely insensitive to the sounds of the piano, was put on the most instrument, then when taking a note, both instantly hid in the hole. After a while, they appeared again on her surface, but when the note was taken in a violin veneer, they retired again. " These vibrations of the piano cap were obviously perceived, obviously, the connivals of worms.

The method of collecting worms, practiced in Florida, is based on a highly developed touch: a board or a stick sticks into the soil, abundantly inhabited by worms, and in its upper edge they will lead another stick as a violin bow (this method is called "violin"). They write that the worms at the same time leave minks and in the set goes on the surface.

In the scientific literature, reports of sounds published by rainworms appeared in the scientific literature. Indeed, with friction of the body and bristles about the soil, with piston movements in wet minks, when rubbing food in the throat, when draining leaves and pebbles, etc. sounds may occur. They are better noticeable than worms more and what they are larger. But it is very doubtful that these sounds would have some kind of biological meaning.

In addition to sensitive nerve cells, nerve endings and photosensitive cells in the outer epithelium, a large number of organs represented by cell complexes are scattered. They are called sometimes sensitive kidneys. Several tens of sensitive cells form a cylindrical or egg-shaped complex (Fig. 23). These are sensitive nervous cells and long nerve processes that go into the abdominal nerve chain. The surface of the cuticle in the area of \u200b\u200bsensitive kidney is somewhat raised, and each cell is equipped with a sensitive hair. These microscopic organs are distributed in large quantities throughout the body, but they are especially numerous in the 1st segment and in its head blade, where large species They are numbered about 1800. The function of them is definitely not installed. As some researchers believe, some of them can carry a tactile function. But it is hardly possible to doubt that the functions of smell and taste are also carried out. In favor of such a conclusion, the fact that these bodies are in large quantities in the oral cavity are evidenced.

Sense of smell, i.e., the ability to recognize various substances in gaseous condition (which is the ability to perceive odors), developed by worms relatively. Salabo. In the experiments of Darwin, the worms did not react to the smell of tobacco juice, spirits, acetic acidBut the slices of Luke (which they love very much) and the leaves of the cabbage they found the smell. On the ether, brought close to the front end of the body, the worms reacted negatively and immediately eliminated from it.

The feeling of taste, i.e. the ability to recognize chemical differences in substances in contact with them, developed by worms very subtle and along with a sense of touch serves for them the main source of perception of the events of the outside world. The experiments of Darwin developed recently a number of researchers, the ability of worms to choose to choose food proven completely indisputable and objections made by some authors on this occasion (for example, Tarnani, 1928) are undoubtedly based on errors.

A very accurate formulation of experiments to determine the taste abilities of worms developed by Mangold (Mangold, 1924, 1951) is as follows. Cherry leaves rolled into the tube or a bunch of several pine needles are bandaged in several places with threads and boils. All flavoring substances are thus removed from them. Then one half of the "taste test" will dip in a clean 20% gelatin, the other half - in the same gelatin, in which the test substance was added - crushed leaves different trees Both herbs, acids, chinin, etc. Such tastes of taste are put on the night on the surface of the earth of flower pots, in which worms are cultivated. At the morning, they count how many testes of the worms dragged into minks and at the same time noted, for which ends of the test, the worm seized. It must be said that the worms, collecting food falling on the surface of the earth, never deeply introduced it in mink, and left it near the outdoor hole or only made it to him. Therefore, the above calculation is not difficult. If the worm does not distinguish the end of the taste of taste, then with a sufficiently large number of repetitions of experience, it should be that both for the one and after his end, the worm is taken equally often. If he prefers the test substance to clean gelatin, then the end impressed to them should be more often ahead when slapping. On the contrary, if the substance turns out to be worse than clean gelatin, then the worm must be seized for him less often. This experience is modified by raging the flavors of tastes of taste, impregnated with different substances, followed by the determination of the number of machines drawn into minks and others. The results were processed statistically. The experiments have shown that worms prefer rotting leaves just fallen autumn; Even less likely, they are fresh green leaves and to an even lesser extent - dried green. Clean gelatin attracts them more than dried leaves. The rotting leaves of different plants can be lined up in such a series in the order of decreasing tendency to them: Iva, sweet Lupine, walnut, White Acacia, Topol, Oak, Gorky Lupine, Lipa, Beech, Adhesives, horse chestnut. Fresh leaves are located at all in another serial row. From gelatin with an admixture of quinine, worms refuse, and this substance feels already at a concentration of 0.07%. From mineral acids, they refuse any concentrations, but they like to gelatin 1-2% of lemon and phosphoric acids. They are indifferent to the Saharas, but from very strong sugar solutions refused at all. A negative reaction is already found to sapherin already starting with insignificant concentrations.

The ability to identify the form of bodies in the worms seems to be absent. Preferred drainage in mink leaves for the front end, and pine needles for the base (fact set by Darwin), further research is confirmed. However, the experiments of the Mangold found that the worms are guided only by a sense of taste, allowing them to distinguish the top of the sheet from a stuff.

Speaking about the reflex activity of rainwrites, it should be noted that they have long been proven to learn and change behavior in connection with experienced previously sensations, i.e., conditional reflexes. Without going into details of quite complex experiments that have established this fact, we mention that the worms can "remember" the road on which they do not face electric shock, and if the electric strike is accompanied by touching sandpaper, then the worms begin to avoid eathed paper without electric current Although it is by itself and does not cause changes in the direction of the movement of worms. In experiments with the definition of flavors, the worms also found out that the reaction to the proposed substance varies in connection with the preceding tests. Chervi usually first refuse unfamiliar food, but then they often get used to them and take it if there are other familiar food.

As already noted (p. 39), the device that ensures the presence of conditional reflexes can be localized and in parts of the nervous system that does not correspond to the brain of higher forms. Determine where this function is localized by the rainworms, is a matter of future research.

To complete the consideration of reflex reactions in the rainworms, let us touch on the question of their pain.

Can these animals experience pain?

Wonderful Russian zoologist V. Faudek considered painful sensations as useful adaptations, the role of which consists in signaling the presence of damage to the body. He tried to trace the emergence of this sign in the evolution of the world of animals and leads a rainworm as an example of an animal for which the feeling of pain is still not available. If we, pointing the rainwater worm, notice his fast whistle movements, it suggests an analogy with a creature, cordoned from pain. How unreasonable, however, such an analogy shows the following simple experience: if the worm, calmly creeping forward, cut the razor in half, then the rear half will be whipped to shrink, imitating painful sensations of higher animals, and the front will calmly continue to pronounce forward, "without noticing" damage . Candle the feeling of pain rear half of the worm and refuse it in front of the front - clearly ridiculous. But this means that we have no right to attribute a feeling of pain with a declining whole rainwright worm.

8. Internal secretion bodies

We mention about the presence of the rainwoods of substances produced in certain places of the body and serving the chemical pathogens of various manifestations of the body's vital activity. Such substances are called hormones (a Greek word meaning "exciting"), and the process of their education is internal secretion. The vertebrates of hormone production occurs in part in the special glands of internal secretion (for example, adrenal glands, thyroid, pituitary), as well as in organs performing simultaneously and other function (for example, sex glands, pancreas, brain cells).

There are no rainworms of special inland secretion glands, but the hormones are produced in different parts of the nervous system. It has long been known that in the ganglia of the abdominal nervous chain of worms, there are so-called chromaffine cells, which allocate adrenaline, i.e. the substance produced by the central part of the superior vertebrates. This substance is known is a specific pathogen of nervous apparatuses that lead the muscles of the walls of blood vessels and employees to regulate the width of the blood vessels of the circulatory system, and thus blood pressure. At the rainworms, this substance plays the same role.

Recently, it was found that a significant part of the nerve cells of the ganglion also carries an intracerecretory function (Herlant-Meewis, 1956). There are two types of such nerve cells: one of them - with a homogeneous protoplasm, others - with a grainy. The first, as believed to serve as germ activity regulators, and the substance produced by them seems to slow down the activity of the genital glands: they begin to function in those months when the reproduction of worms ends and disappear during periods of reproduction. Granular cells are important when healing wounds and restoring lost parts of the body (regeneration): during these processes, secretion in them is particularly enhanced.

The activity of the rusting of the rainwrites, which lies in the development of shells and nutrient content of egg cocoons, is also undoubtedly regulated by hormones. At one time it was believed that hormones that excite the activity of ferrous cells of the belt are produced by male sex cells, ripening in seed bags. However, it turned out to be incorrect. But the activity of the belt is undoubtedly regulated by some hormones: if we transplant a piece of belt from a worm with an inactive belt to a sexual activity that is in fullings, the transplanted piece quickly acquires the properties of the recent belt. The place of production of hormones regulating the activity of the gland glands is still unknown.

9. Premunition bodies

Rain Cerves multiply only by laying eggs enclosed in special egg cocoons.

Consider how they are organized by the organs that ensure the formation of eggs, their fertilization and tend. The combination of these organs forms the sexual apparatus for men and female genitals are in the rainworms in the same individual; Thus, among them there are no male and female individuals, but they are all sort of creatures, or, as they are called, hermaphrodites.

Eggs are also formed by Pars of very small female sex glands - ovaries, which are strengthened on the partition between the 12th and 13th segments from the abdominal side (Fig. 24). The ovaries are very simple. They are complexes of emerging eggs; The earliest stages of development are in the part adjacent to the intersegment partition, where the ovary consists of small cells. The largest cells are located at the free rear end of the ovary facing the body cavity. Here, egg cells achieve their final sizes (about 0.1 mm in the diameter) and fall into the body cavity. Rounding worms spherical eggs or slightly elongated. They are almost transparent, since in their protoplasm there is only a very small amount of nutrient grains - yolk. The absence of a sufficient amount of nutrient material for a developing embryo inside the egg causes the need to supply it from the outside with the help of an egg cocoon protein.

Eggs finish ripening in the so-called egg bags. These are blind bag-shaped protrusions of intersegment partitions, in which eggs falling away from the back of the ovary.

Eggs are output through short ovages that begin with egg funnels in the 13th segment, then the partition between the 13th and 14th segments are opened and open on the abdominal side of the 14th segment (Fig. 24). The egg funnels are equipped with cilia, the operation of which eggs are trampled from egg bags and at the right moment (during the formation of an egg cocoon) are output from the ovage.

Men's sex glands - the seeds are also very small. Among the two pairs, they are placed on partitions between the 9th and 10th segments and between the 10th and 11th (Fig. 24). Male sex cells - sperm - only begin development in these tiny small calves. Complexes of future spermatozoa in the form of microscopic lumps of rounded cells fall into the cavity of the body P from there enter the seed bags, which are the dominant growth of integmentation partitions. The amount, form, location and relative sizes of seed bags vary and serve as an important feature in determining worms.

In some types of rainwoods (in octolasium and lumbricus), the abdominal part of the body cavity near the semenniks is fenced off by a special wall from the main cavity of the segment; The so-called seed capsules are obtained. Due to their presence, the forming lumps of spermatozoa cannot be distributed throughout the cavity of the segment and it creates a more direct path to seed bags (Fig. 24).

To remove spermatozoa, serve seed funnels and semi-led (RPS. 24). Seed funnels are usually large; They are well visible at the opening of the worms. Semi-cereals in which spermatozoa from seed funnels are coming are very thin cylindrical tubes, heading along the abdominal wall of the Kzdadi body. Sexuals from the Funnel of the 10th and 11th segments in the 12th segment merge with each other, and the total tube of the seven-part on each side of the body stretches until the 15th segment, where it passes through the thickness of the body wall and ends with a male sexual (sometimes ), usually having a type of vertical gap.

Male genital holes are sitting on more or less highly developed ferrous pillows. These pillows, except ferrous cells, contain a large number of vessels that are filled with blood during pairing.

The original feature of the sexual apparatus of unauthorized rings to which the rainworms belong are semi-art (Fig. 24) - small spherical hollow bags, tightly pressed against the wall of the body cavity. The ducts of the semichentics pass through the thickness of the body of the body and open outdoor pores located in intersegment grooves. The walls of the semichentics contain a musculature, the action of which the seminal liquid can be absorbed into the semi-artist and, on the contrary, spray from it outward. This musculature acts like a rubber cap pipette. SEEPPERIRITIES Sometimes 2 or 3 pairs; They can be located on the side, on the abdominal side, or may be (as in Eisenia) shifted on the spinal side, up to the midline. But it should be borne in mind that some types of rainwoods are missing seeds.

The rainworms belongings should be attributed to the reproduction authorities. The worms that have reached puberty, the belt is always noticeable, but its appearance depends on the season and the state of fatness. During periods of breeding, the belt swells greatly. Its function is the formation of egg cocoons.

The belt is the modification of the outer epithelium. In the area of \u200b\u200bthe belt, the outer epithelium is very thickened. All cells acquire iron-free character; Among them, three types can be outlined: 1) relatively small cells that do not contain grains - mucous cells; 2) medium-sized cells containing large grains that form an egg cocoon sheath; 3) Huge fine-grained cells that produce a protein substance that constitutes the contents of an egg cocoon and a power serving for developing embryos (Fig. 25). In addition to iron cells, a large number of blood vessels and nerve endings can be seen in the belt.

A number of other glands on the abdominal side of the body between the belt and the front of the body are also involved in the reproduction function. Especially noticeable gland on the 10th and 11th segments, which give this part of the body surface of a hawk worms whitish hue. In addition, near the abdominal bristles in the specified part of the body on some segments, sometimes only on one side of the body, there are developed glands, noticeable in the form of small swelling. Often, the bristles themselves are changed, turned into the so-called sex bristles that are functioning in pairing to keep partner and to push the pores of sevenxists. Sometimes genital bristles differ from the usual only large sizes, but some species differ very much and in shape (Fig. 26). Formed, on the one hand, sharp stilettage, obviously styled when mating into the skin of a partner, and on the other, the bristles introduced into the pores of the semi-lenterns.

Animals, suburbs of rainworms. The body of a rainwater worm consists of ring-shaped segments, the number of segments can reach up to 320. Navigating, the rain worms are based on short bristles, which are located on the bodies segments. When studying the structure of the rainworm, it can be seen that, unlike the power, his body looks like a long tube. Rainy worms are distributed throughout the planet, except Antarctica.

Appearance

Adult rainworms are 15 - 30 cm long. In the south of Ukraine, he can achieve large sizes. The body is a smooth, slippery, has a cylindrical shape and consists of piece rings - segments. This form of the worm body is explained by his life, it facilitates movement in the soil. The number of segments can reach 200. The abdominal side of the body is flat, spinal - convex and darker than abdominal. Approximately where the front of the body ends, the worm has a thickening called belt. It places special glands allocating adhesive liquid. In the reproduction of it, an egg cocoon is formed, inside which evil eggs develop.

Lifestyle

If after the rain go into the garden, then you can usually see small bugs of the earth, thrown by rainworms. Often, at the same time, the worms themselves are crawling along the path. It is precisely because they appear on the surface of the earth after the rain, they are called rain. These worms crawl on the surface of the earth also at night. Usually, the rainwill lives in a rich humid soil and is not common on sandy soils. He also lives on the swamps. Such features of its propagation are explained by the way of breathing. The rainwill breathes the entire surface of the body, which is covered with mucous membranes, wet skin. It was dissolved in water too little air, and therefore the rainworm is choking there. Even faster, he dies in dry soil: his skin dries out, and breathing stops. In warm and wet weather, the rainworms are closer to the ground surface. During long drought, as well as in cold period They crawl deep into the ground.

Move

The rainworm moves crawl. At the same time, he first pulls the front end of the body and clings to the bristles located on the abdominal side, for the rootiness of the soil, and then, cutting the muscles, pulls the rear end of the body. Moving under the ground, the worm pavements in the soil. At the same time, he spreads the earth with a pointed end of the body and is silent between its particles.

Moving in dense soil, the worm swallows the earth and skips it through the intestines. The star of the worm usually swallows at a considerable depth, but throws over the anal hole at its mink. So on the surface of the Earth, long "shoes" from the ground and lumps, which can be seen in the summer on the garden paths are formed.

This method of movement is possible only in the presence of well-developed muscles. Compared to hydro, the rainworm has a more complex muscles. She lies under his skin. Muscles with skin form a solid skin-muscular bag.

Rainworm muscles are located two layers. The skin is a layer of ring muscles, and under them - a thicker layer of longitudinal muscles. Muscles consist of long contracting fibers. When reducing the longitudinal muscles, the worm's body becomes shorter and thick. When cutting ring muscles, on the contrary, the body is done thinner and longer. Reducing alternately, both layers of muscles determine the movement of the worm. The abbreviation of the muscles occurs under the influence of the nervous system branched in muscle tissue. The worm movement is greatly facilitated by the fact that there are small bristles on his body from the abdominal side. They can be felt by having spent in water in the water on the sides and the abdominal side of the body of the worm, from the rear end to the front. With the help of these bristles, the rainworm moves underground. They are delayed when he is pulled out of the ground. With the help of bristles, the worm is lowered and rises along its earthen moves.

Food

Rain worms are powered preferably by half-making plants residues. They will typing, usually at night, in their mink leaves, stalks, and so on. The rainworms are also powered by a rich in humus, passing it through the intestines.

Circulatory system

The rainworm has a circulatory system, which does not have a hydra. This system consists of two longitudinal vessels - spinal and abdominal - and branches that connect these vessels and divert blood. Muscular walls of vessels, shrinking, drive blood throughout the body of the worm.

Blood near the rainworm is red, it has for a worm, as for other animals - very important. With the help of blood, the relationship between the animal bodies is determined, metabolism occurs. Moving through the body, it will spread the nutrients from the digestive organs, as well as the oxygen flowing through the skin. At the same time, blood makes carbon dioxide from tissues into the skin. Various unnecessary and harmful substances formed in all parts of the body, together with blood enter the allocation bodies.

Irritation

Special organs of feelings have no rainworm. External irritation is perceived by the nervous system. A touchless feeling is most developed in the rainworm. Sensitive tactile nerve cells are located along the entire surface of its body. The sensitivity of the rainworm to a different kind of external irritation is quite large. The most light oscillations of the soil make it quickly hide, swallowed in a mink or in deeper soil layers.

The value of sensitive skin cells is not limited to touch. It is known that rainworms, without having special organs of vision, still perceive light irritation. If at night suddenly illuminate the worm with a flashlight, it quickly hides.

Animal response to irritation carried out with the help of the nervous system is called reflex. There are different kinds of reflexes. Reducing the body of the worm of touch, its movement with a flashlight sudden illumination has a protective value. This is a protective reflex. Capturing food - digestive reflex.

Experiments also show that the rainworms feel smells. The smell helps the worm of food. Another Charles Darwin found that the rainworms are well distinguished by the smell of the leaves of the plants that feed.

Reproduction

Unlike the hydra, the rainworm is multiplied exclusively by sexually. He has no useless reproduction. Every rainwater worm has men's organs - Tsemenniki, in which livestock develops, and female genitals - ovaries, in which - egg cells are formed. The worm shocks her eggs into the cocoon mucous. It is formed from the substance allocated by the worm's belief. In the form of a clutch cocoon slides with a worm and tightened at the ends. In this form, the cocoon remains in an earthen mink before the release of young worms from it. Cocoon prevents eggs from dampness and other adverse effects. Each egg in the cocoon is divided many times, as a result of which the fabrics and organs of the animal are gradually formed, and finally, small worms are out of cocons, similar to adults.

Regeneration

Like hydrauli, rainworms are capable of regeneration at which lost parts of the body are restored.