Meaning of the word worm. Earthworm

Explanatory Dictionary of the Living Great Russian Language, Dal Vladimir

worm

m. worm, worm; worm, worm, worm, worm ver. (from the belly, womb); a ringed, legless animal that crawls and reptiles; In common parlance, caterpillars are also called worms, esp. carnivores, in the body of animals or in corpses, as well as gutters and worms. The perch bites on a worm, takes on an earthworm, an earthworm. A worm in the dust is God's creation. He won't even crush a worm, meek man. The worm will eat all flesh. Kill the worm, have a snack for hunger. Like a worm in a nut, there is sadness in the heart. Not just a worm that accidentally eats a person, but a worm that eats a person! Even a worm succeeds forever. Without God, even a worm will devour. Earthworms crawl out - to bad weather.

Worms, plural red suit in cards, with heart-shaped points; Vlad's hooves

Worm, hypoglossal ligament, frenulum, in humans and animals.

Worms, tul. surega, buckwheat kvass dough, mashed into a sieve and sprinkled with vegetable oil. Worm-like, worm-like, worm-like, related to worms. Worm tin where anglerfish keep their worms. Worm profit, from a worm. Chervezhnik m. Chervezhnitsa w. whoever drives the caterpillars tinkers with them; who digs for worms on the fishing rod, etc. Wormy, in which the worms have appeared, what has been eaten by them. Wormy corpse; - apple, tree, wormhole, wormhole, wormhole, wormhole is also a passage, a hole made by a worm. Pear with a wormhole. Wormboy for bread, for coniferous forest. Worm tree. Worm-broken, worm-beaten bread, forest, fruits. A wormhole is not a reproach for a red apple. Worthy south. north wormy. Basok (red on the outside), but dark-colored. To worm something, to make something wormy; worm, become wormy, be eaten by worms, caterpillars. Cherva baby, baby, devil, offspring of bees, eggs, caterpillars and larvae; each black cell contains one testicle; The bees feed the caterpillars with beebread and bread, and the larva is sealed tightly with wax; this is a printed or covered devil. To draw, about the uterus, to sow, to seed, to lay eggs. Blackened cells, blackened, each containing a testicle. Worm, worm a hive, transplant a nest, foundation with worm, from hive to hive. Chervlenye, active according to verb.

The creation of a uterus of cherry, children, the production of testicles, offspring. Cherit, the same thing where they say devil instead of worm. The uterus began to draw. Chervenitsa arch. a type of shovel used to dig worms for fishing.

Plant, see buglaz. Worm, legless lizard of hot countries. Wormworm, Coecilia, a reptile of hot countries, similar to a snake, a legless toad; other types of her eyeslessness. The scale insect is the insect Coccus, cochineal, which produces the paint scale scale; a simple analysis of it: a stationery seed.

Composition of antimony and sulfur, kermes. Cherven m. old. the month of June, time to collect worms in the western provinces;

church yarn or fabrics dyed with worms. Wormworm m. Barbada plant? turnip?

Plant. Potentilla argentea. Wormgrass m. Wormworm, wormy grass and wormweed, woodworm or wormweed, zabirukha, ironweed, male toadweed? gourd? milk, rake, five-leaf, ulubnik, dog; In southern and western Rus', worms are collected from its roots.

The mealybug and mealybug are also plants. Scleranthus annuus, diwala, sapless grass, cochineal, gum, clerical root.

Wormweed plant Thlaspi arvense, jarutka, moneyman, talaban, verednik, toadwort, golichek, comelek, klopets? Chervenitsa (wormwort), dye plant, Anchusa tinctoria. Scarlet, worm-like, crimson and crimson, the color of a worm, bright crimson. Chlamys of scarlet, church. And there is a royal coffin made of wood, lined with cherry velvet in the middle and worm-like on top, Kotoshikhin. The banner is scarlet, the bangs are scarlet, The Tale of Igor's Campaign. Scarlet scarlet, scarlet f. clothes of this color are now more ceremonial outerwear of the sovereign, ermine covered with worm cloth, mantle, purple.

Worm, scarlet yarn. Chervlenichny, from crimson yarn, fabric. Chervlenets m. paint chervets, chervtsevaya, gaff, crimson, crimson. Scarletness w. purplishness, purplishness. To scarlet, to paint with scarlet paint; turn scarlet, become scarlet, turn purple, turn purple. Sunset, sunrise turns scarlet. Chervlen cherlen or cherled, bright red vohra, ferruginous clay, which is used to paint fences, roofs, etc. Chervonny yuzhn. zap. red, scarlet, bright red.

To worms, card suit, related. Ace of hearts. Chervonka, red card. Chervony noun. or chervonets m. gold coin about three rubles for silver, beam, Dutch gold. Red gold, the kindness that goes into chervonets. Vermigonal (worm-running) drugs, anthelmintics. Chervogon, chervogon, plant. Zygophillum. Worm-shaped, worm-shaped, worm-shaped or worm-like, similar to a worm.

Explanatory dictionary of the Russian language. D.N. Ushakov

worm

worm, m. An ancient name for the letter "h".

worm

worm, plural worms, worms, m.

An oblong, soft-bodied, boneless animal. Earthworm. You are buried in the bitter cold, the greedy worm has not touched you. Nekrasov.

Insect larva (colloquial). Silkworms.

trans. Insignificance (rhetor.). I am a king, I am a slave, I am a worm, I am a god. Derzhavin.

trans. Symbolic designation of painful, excruciating anxiety (book). A worm of suffering lurked in my chest. A.

Explanatory dictionary of the Russian language. S.I.Ozhegov, N.Yu.Shvedova.

worm

I, plural -and, -ey, m.

A boneless crawling animal with an elongated body. Flat, annelid worms. Earthen ch. Mulberry ch. (silkworm caterpillar).

trans., what. In combination with the words “doubt”, “repentance”, “envy” and some others: about a hidden, constantly tormenting feeling. Hours of doubt sharpen the heart.

adj. wormy, -th, oh (to 1 meaning).

New explanatory dictionary of the Russian language, T. F. Efremova.

worm

1. An invertebrate animal that moves by bending its long body.

   decomposition An insect larva similar to such an animal.

   Usage as a symbol of painful, painful anxiety.

m. Pathetic, insignificant person; nonentity.

m. The name of the letter of the ancient Slavic or old Russian alphabet.

Encyclopedic Dictionary, 1998

Worm (novel)

"Worm", "Doll" - last novel English writer John Fowles, published in 1985. The work describes the fictional events preceding the birth of the founder of the Shaker sect, Anna Lee, moved by the author one year ahead compared to real events, in February 1737. The title of the novel, explained by the author in the prologue, refers to the meaning used at the end of the 17th - beginning of the 18th century English word maggot, which had the meaning of “whim, fantasy”; other possible interpretations of the title become clear as the narrative progresses. The style and metanarrative techniques used by Fowles allowed critics to classify this novel as postmodern literature.

The chronology of the events of the novel is clearly indicated; they begin at the end of April 1736, when a group of the main participants in the events described is formed. Described from different points of view, at first as some personal vision of the author, they are later conveyed from a third person and in the form of interrogations conducted under oath by the lawyer Henry Askew on behalf of his noble employer, probably the Duke, concerned about the disappearance of his youngest son. It's gradually clearing up outer side events, according to which the disappeared, calling himself "Mr. Bartholomew", accompanied initially only by his deaf-mute servant Dick, hires three companions to make a mysterious journey. These companions are London's Rebecca Hocknell, actor John Lacey and unemployed David Jones. Each of them, during the interrogation process, sets out different versions of what happened, according to the degree of their awareness and life views. From their testimony, the reader learns that the educated and alien to life’s temptations “Bartholomew”, wanting to come into contact with certain “guardians of the waters”, and fearing surveillance of himself on the way through Exmoor, hires Lacey and Jones so that with their presence they distract the attention to yourself. Rebecca's role remains unclear. The version proposed at the beginning that she was hired to participate in an orgy and then a satanic rite is refuted by Rebecca’s own version, according to which she witnessed “Bartholomew” communicating with members of the Trinity, first at Stonehenge and then in a Devonshire cave; “Bartholomew” himself returned to Heaven, where he, in a sense, came from. A modern reader in her description can assume a story about contact with extraterrestrial civilization or time travelers. the last part The book is dedicated to the further life of Rebecca and her family, who replaced their initially Quaker beliefs with more radical ones, close to the Camisards.

Throughout the book, the author shares his attitude to what is happening, explains the motivations of the characters in the story based on the ideas of various classes characteristic of that time about the predetermination of their position, the role of their "", individualism, women's rights, progress. The author also provides various details about the life and laws of England in the 1730s, placing his work in historical context. Thus, mention is made of the Witchcraft Law adopted a year before the events described, which made it illegal to accuse someone of witchcraft; adopted, providing for severe punishments for the most minor offenses. The novel also contains references to literary works and authors of the 18th-19th centuries. Thus, Fowles writes that he sought to use the techniques of Daniel Defoe. He also reports that John Lacey acted in Henry Fielding's play "Pasquin" - interestingly, what is the title of one of this author's plays. The mention in one of Askew's letters of the riots caused by the captain's actions in Edinburgh may be a reference to the novel Edinburgh Dungeon by Walter Scotus, which describes these riots, and the style of the narration is reminiscent of Fowles's techniques in that novel. Moreover, the story of the appearance of the devil in the form of a black man, told in Scot's novel through the mouth of his character David Deans, is reminiscent of the version of events at Stonehenge told by Rebecca to David Jones.

The novel was translated into Russian twice: by V. Lanchikov as “Worm” in 1996, and by A. Safronov and O. Serebryannaya as “Doll” in 2011.

Examples of the use of the word worm in literature.

Romuald - young decay of West Africa, avant-garde bank worms.

These goods were sea animals: sponges, tunicates, sea anemones, all kinds of starfish, mollusks, barnacles, worms, creeping flowers of the sea, sea ​​urchins- spiny, inconspicuous bigheads, crabs, seahorses, sea goats - so transparent that they hardly give a shadow - in a word, a fabulous, multifaceted world of smaller brothers, the inhabitants of the ocean.

At home, secluded in his stone cell and settled on the worn-out worms On the table, a heavy copper inkwell, brought with him, Alexy translated the fiery words of the Teacher, who rejected all earthly gain, and immediately remembered who and what kind of bribe should be given tomorrow in the secret of the great Chartophylact and who should not be offended by handing a bribe to his blood enemy.

Amirani cut off the last head of the dragon, three crawled out worm: white, yellow and blue.

Where the flies will sit, there worms they start where their anda is, there is cunning, deceit, deception.

Every person is secretly gnawing worm anti-state feelings, because any power puts pressure.

During the years of perestroika, when worm anti-state feelings were fed to incredible proportions, all parts of the state were under fire - from economic bodies, the military-industrial complex, the army and the police to the school education system and orphanages.

He stepped on sea cucumbers that were peacefully swallowing mud, on starfish that slowly crawled along the bottom, on marble-white sac-like ascidians that burst under his heavy soles, on calcareous tubes worms, sticking out their feathery gills with the finest branched pattern of the circulatory system.

Lifting Guyer with difficulty, he tipped him over the edge of the basket just as the giant red worm rammed the wall - to stop such a monster, little aerosol was sprayed.

There the girls, while we were carrying canoes, managed to dig worms for fishing and steal an old iron iron with an unclear past and future.

We also met Ulva - sea ​​salad, whose broad leaves are edible, and with red algae, phyllophora and coralline, and with sea worms, which hide in tube houses, and with the sea acorn, one of the most tenacious and tenacious stowaways.

On the plate was written: CHIGI CAPELLA Built according to the design of Raphael All interior decoration was created by Lorenzo Bernini Langdon re-read the inscription twice, but he was still chewing on it worm doubts.

A scorching heat burst through the armored glass, fiery worm disappeared from view, but by the trembling of the air above the slope, by the clouds of steam and the sheaves of crackling sparks into which the bushes turned, we realized that he was moving towards the top of the hill.

I hit, choose the last trump card, win back B10 worms, I move to the table for the queen of spades and my missing diamonds fly to the ace worms and the king of clubs.

Dissolve me quickly, what could be burning like that, not Rzhavyi’s intestines? Worm, In fact?

In different sources you can find “earthworms”, “dung worms”, “earthworms”, “compost worms”, etc. Let’s figure out what worms are called correctly and how they differ.

Earthworms called family large soil oligochaete worms Lumbricidae (Lumbricidae), which belong to the order of higher oligochaete worms Lumbricomorpha, class of oligochaete worms Oligochaeta (Oligochaeta), subphylum of belt worms Clitellata (Clitellata), type annelids Annelida (Annelida). The phylum annelids, or annelids, covers a significant number of species (about 9000) of higher worms.

Species of earthworms differ not only in structure, but also in habitat, lifestyle and special role in the soil-forming process. All family species lumbricidae (Lumbricidae) grouped in eight births, of which the most studied genus Eisenia. A representative of this genus, the dung worm Foetida (Eisenia Foetida), is cultivated in Russia.

Therefore, a dung worm can safely be called an earthworm - this is simply a more generalized concept.

Categories of worms according to their behavior

Earthworms are grouped into three categories according to their behavior in natural environment: anecic, endogeic and epigeic.

Anecic species build vertical burrows depth up to 1.5-2 meters. They feed on fermented organic matter to a certain extent on the soil surface and convert it into humus. If these worms are deprived of their permanent habitat, they stop reproducing and growing. They are very important for soil formation. The main species are Lumbricus terrestris and Aporrectodea longa.

Endogeic varieties, type Aporrectodea calignosa, build comprehensive, mostly horizontal burrows where they remain most of the time, feeding on mineral particles in the soil. Prefer less saturated soil organic substances. This is the only variety earthworms that actually feed big amount soil. Moving through the soil and passing it through their intestines, they mix and aerate it, and also enrich it with nutrients and microflora.

Epigeic species do not build permanent burrows, they usually live in the top layer of soil, for example, in the forest under piles of leaves - i.e. in areas rich in organic raw materials. Quite often they can be found in manure heaps. Due to the fact that they do not make deep holes and prefer to eat material rich in organic matter, they are easy to adapt to vermiculture. This is exactly what it is those same worms Eisenia foetida and Eisenia andreii. They make up approximately 80-90% of earthworms used in large-scale commercial operations.

That diligent Californian

Eisenia foetida is the California red worm. Thus, it is accurate to call the Californian both “rainy” and “dungy.” The same applies to the Prospector worm - this is also Eisenia foetida.

The only difference is that different populations of the same worms were used for selection. The Californian was bred in California using local worms, and the Prospector was bred in our country, in the Vladimir region, by crossing a local worm and a worm from Kyrgyzstan.

Therefore, both the red Californian worm and the prospector worm can be called breeds earthworm Eisenia foetida.

Igonin A.M. about the differences between a prospector and a Californian

In his book “How to increase soil fertility tens of times with the help of earthworms” (2000, third edition), Professor Igonin writes “comparative and parallel studies of our technological worms and red Californian worms did not reveal any differences between them in 14 characteristics.”

Let us recall that it was Anatoly Mikhailovich Igonin who developed the “prospector” breed of earthworms in the 80s of the last century.

How to increase soil fertility using California worms, S. Kulish (2005)

How to increase soil fertility tens of times with the help of earthworms, A. Igonin (2000)

When a fisherman digs for worms for an upcoming fishing trip, he, of course, wants to find something bigger. But what would he say if he discovered a 3-meter-long worm underground? Meanwhile, such worms are found in Australia. True, no one hooks them - their numbers are already too small, so they are under state protection.

Australian giant earthworm (lat. Megascolides australis) is the largest of all known underground invertebrates in the world. It lives exclusively in Gippsland, a rural region of Victoria with an area of ​​just 1000 square meters. km. And even then, you can’t find it on every corner here - like a real earthworm, it chooses clayey and moist soil to live near water bodies.

Or maybe it was earlier - when the entire south of modern Gippsland was covered with dense eucalyptus forests, giant worms had a place to settle. However, the trees were cut down to make way for Agriculture, and the soil itself was constantly disturbed: they plowed, planted seeds, fertilized and plowed again. This place became uncomfortable for an earthworm of this size, so it had to settle on the remaining small and isolated remnants of the forest.

An adult individual of the giant Australian worm reaches a length of 2.5-3 meters with a body thickness of 2-3 cm and a weight of about 700 g. It is not surprising that from a distance it can be confused with a long, emaciated snake. However, upon closer examination, the segments characteristic of all earthworms are clearly visible, of which the Australian giant has at least three hundred.

Giant earthworms rarely crawl to the surface - they spend their entire lives in long underground tunnels that they dig themselves. Usually the worm digs the ground with the front part of its body, however, if the soil is too hard, it passes it through the intestines and throws it out in heaps to the surface. One individual can process 500-700 g of soil per day.

It's funny that when moving underground, the giant worm behaves very noisily - smacking, gurgling or buzzing. And all because the walls of its tunnels are covered with a special secretion that facilitates sliding. Australian earthworms breed in spring and summer. They are hermaphrodites, but require a mate for successful fertilization. After mating, each partner lays eggs in a pre-constructed cocoon.

The eggs of the giant earthworm mature and develop over the course of a whole year. The hatched cubs are no different from their parents in anything except their size. The length of their body, by our standards, is no longer small - 20 cm, but only after 5 years they grow to their final size and begin to reproduce. The maximum lifespan of giant Australian worms is 10 years.

Residents of Australia greatly respect their unusual neighbors. In their honor, they even established the annual international festival “Karmai” (the name of the worm in the dialect of the local aborigines). In addition, in 1985, a hundred-meter museum attraction dedicated to the giant earthworm was built.

- (Vermes), a collective group of invertebrates, uniting lower bilaterally symmetrical animals (Bilateria) with an elongated body, the swarm was previously given the rank of type. Modern Researchers divide Ch. into independent types: flat Ch., nemerteans,... ... Biological encyclopedic Dictionary

- (Vermes) extensive gr. invertebrates, characterized by a number of common features: a bilateral body structure, the development of a skin-muscular sac that envelops the body and consists of a single-layer epithelium and differently structured muscles, the absence... ... Geological encyclopedia

Worm, worm... Russian word stress

1. WORMS, her; WORTS, worm; pl. (unit of heart, s; g.). Card suit, indicated by red hearts. Lead hearts. Seven of Hearts. Ch. trumps. On hand are one piece ◁ Hearts; Chervonny, oh, oh. Ch. ace, king. 2. WORMS see Worm. * * * worms... ... encyclopedic Dictionary

Hearts, hearts, suit, worms, worm Dictionary of Russian synonyms. worms noun, number of synonyms: 6 fats (5) suit... Synonym dictionary

WORMS- (vermes), a type (and according to some authors a group of types) of invertebrate animals, occupying, in terms of the height of their organization, a kind of middle position between coelenterates, on the one hand, and arthropods (and soft-bodied animals) on the other. Ch. have b. h... ... Great Medical Encyclopedia

worms- WORMS, worms, unraveled. reduction heart... Dictionary-thesaurus of synonyms of Russian speech

WORMS, a collective group of invertebrate animals. Most worms have an elongated body, the walls of which consist of skin and muscles. About 40 thousand species. Free-living forms live in the seas, fresh waters and soil. Besides,… … Modern encyclopedia

A collective group of protostomed invertebrate animals with an elongated body, uniting flatworms, protocavity worms, netelminthes, nemerteans, annelids, etc. Big Encyclopedic Dictionary

WORMS, worms. see hearts. Dictionary Ushakova. D.N. Ushakov. 1935 1940 … Ushakov's Explanatory Dictionary

WORMS, ey, yam and WORMS, worm, worms. IN playing cards: The name of the red suit with hearts. King of Hearts. | adj. red, aya, oh and hearts, aya, oh (colloquial). Queen of Hearts. Ozhegov's explanatory dictionary. S.I. Ozhegov, N.Yu. Shvedova... ... Ozhegov's Explanatory Dictionary

Books

• Worms, R. Flanagan. 1995 edition. The condition is very good. A country of many millions, proud of a powerful army, enthusiastically chanting “USA” and an army machine that crushes people under itself. Army and...
• Parasitic worms are the cause of unrecognized diagnoses, O. I. Eliseeva. What is helminthiasis, what types of parasites can inhabit our organs, and what are the known ways of their penetration into human body. Symptoms of helminthiasis and its similarity to...

Annelids have the highest organization compared to other types of worms; for the first time they have a secondary body cavity, a circulatory system that is more highly organized nervous system. In annelids, inside the primary cavity, another, secondary cavity has formed with its own elastic walls made of mesoderm cells. It can be compared to airbags, one pair in each segment of the body. They “swell”, fill the space between the organs and support them. Now each segment received its own support from the bags of the secondary cavity filled with liquid, and the primary cavity lost this function.

They live in soil, fresh and sea water.

External structure

The earthworm has an almost round body in cross section, up to 30 cm long; have 100-180 segments, or segments. In the anterior third of the body there is a thickening - the girdle (its cells function during the period of sexual reproduction and egg laying). On the sides of each segment there are two pairs of short elastic setae, which help the animal when moving in the soil. The body is reddish-brown in color, lighter on the flat ventral side and darker on the convex dorsal side.

Internal structure

Characteristic feature internal structure is that earthworms have developed real tissues. The outside of the body is covered with a layer of ectoderm, the cells of which form the integumentary tissue. The skin epithelium is rich in mucous glandular cells.

Muscles

Under the cells of the skin epithelium there is a well-developed muscle, consisting of a layer of circular muscles and a more powerful layer of longitudinal muscles located under it. Powerful longitudinal and circular muscles change the shape of each segment separately.

The earthworm alternately compresses and lengthens them, then expands and shortens them. Wave-like contractions of the body allow not only crawling through the burrow, but also pushing the soil apart, expanding the movement.

Digestive system

The digestive system begins at the front end of the body with the mouth opening, from which food enters sequentially into the pharynx and esophagus (in earthworms, three pairs of calcareous glands flow into it, the lime coming from them into the esophagus serves to neutralize the acids of rotting leaves on which the animals feed). Then the food passes into the enlarged crop and a small muscular stomach (the muscles in its walls help grind the food).

The midgut stretches from the stomach almost to the posterior end of the body, in which, under the action of enzymes, food is digested and absorbed. Undigested remains enter the short hindgut and are thrown out through the anus. Earthworms feed on half-rotted plant remains, which they swallow along with the soil. As it passes through the intestines, the soil mixes well with organic matter. Earthworm excrement contains five times more nitrogen, seven times more phosphorus and eleven times more potassium than regular soil.

Circulatory system

The circulatory system is closed and consists of blood vessels. The dorsal vessel stretches along the entire body above the intestines, and below it is the abdominal vessel.

In each segment they are united by a ring vessel. In the anterior segments, some annular vessels are thickened, their walls contract and pulsate rhythmically, thanks to which blood is driven from the dorsal vessel to the abdominal one.

The red color of blood is due to the presence of hemoglobin in the plasma. It plays the same role as in humans - nutrients dissolved in the blood and spread throughout the body.

Breath

Most annelids, including earthworms, are characterized by cutaneous respiration; almost all gas exchange is provided by the surface of the body, therefore the worms are very sensitive to moist soil and are not found in dry sandy soils, where their skin quickly dries out, and after rains, when in the soil a lot of water, crawling to the surface.

Nervous system

In the anterior segment of the worm there is a peripharyngeal ring - the largest accumulation of nerve cells. The abdominal nerve cord with nodes of nerve cells in each segment begins with it.

This nodular type nervous system was formed by the fusion of nerve cords on the right and left sides of the body. It ensures the independence of the joints and the coordinated functioning of all organs.

Excretory organs

The excretory organs look like thin, loop-shaped, curved tubes, which open at one end into the body cavity and at the other outside. New, simpler funnel-shaped excretory organs - metanephridia - remove harmful substances into external environment as they accumulate.

Reproduction and development

Reproduction occurs only sexually. Earthworms are hermaphrodites. Their reproductive system is located in several segments of the anterior part. The testes lie in front of the ovaries. When mating, the sperm of each of the two worms is transferred to the seminal receptacles (special cavities) of the other. Cross fertilization of worms.

During copulation (mating) and oviposition, girdle cells on the 32-37 segment secrete mucus, which serves to form an egg cocoon, and a protein liquid to nourish the developing embryo. The secretions of the girdle form a kind of mucous coupling (1).

The worm crawls out of it with its back end first, laying eggs in the mucus. The edges of the coupling stick together and a cocoon is formed, which remains in the earthen hole (2). Embryonic development eggs occur in a cocoon, from which young worms emerge (3).

Sense organs

The sense organs are very poorly developed. The earthworm does not have real organs of vision; their role is played by individual light-sensitive cells located in the skin. The receptors for touch, taste, and smell are also located there. Earthworms are capable of regeneration (easily restore the back part).

Germ layers

The germ layers are the basis of all organs. Annelids have ectoderm (outer layer of cells), endoderm (inner layer of cells) and mesoderm ( intermediate layer cells) appear at the beginning of development as three germ layers. They give rise to all major organ systems, including the secondary cavity and the circulatory system.

These same organ systems are subsequently preserved in all higher animals, and they are formed from the same three germ layers. Thus, higher animals in their development repeat the evolutionary development of their ancestors.