Nugulata(Nemertina, Nemertea, also called Nemertina orRostral cavityFauna〔Rhynchocoela〕)invertebrate。It mainly engages in free life, but there are several parasiticcrab、shrimpandAscidian。About 900 species are known, most of them are marine, and a few live in fresh water orTerrestrial 。
Chinese name
Nugulates
Foreign name
Nemertea Nemertina
Foreign name
Nemertinea
Distribution area
Most of them are marine, and a few live in fresh water or land
Nemerteans, ribbon worms, Sealong worms, Nemertine orms. Also called bootlace worm, proboscis wormnemertean(nemertean、nemertine)。
Nugulates
brief introduction
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Nugulates are coelomorphs, which belong to protocoelomorphs, a phylum of protostomes, also known as neozoa.Because the soft tissue is very developed, the body is soft.The back and abdomen are flat, and the front and back grow in a tie shape, without division.The body surface is covered by cilia, which can secrete a lot of mucus.The digestive tube is very developed and runs straight. There are multiple lateral sacs in the midgut and anus at the rear end.The back of the alimentary canal is covered with the unique kiss of the sect. It is hidden in the kiss sheath and can turn out the front of the body to enter and exit freely.The protonephric duct is its excretory organ.With closed tube vascular circulation system.The brain and the right and left contralateral nerve cords constitute its main nervous system.It is hermaphroditic, and the gonads are saclike, mostly interacting with the side sacs of the midgut.The space between the body wall and the viscera is filled with soft tissue, and the only space in the body is the snout cavity between the snout and the snout sheath.There is no real body cavity.It is a phylum after Platyhelminthes, but it is also included in the broad sense of Platyhelminthes. At this time, planarians, trematodes and tapeworms are collectively called euflathes, and newworms are called rostrata.Nexus is a small family in the animal kingdom, most of which are marine, a few of which are fresh water, wet soil, and parasitic.The body length of the long new-born worm in the coastal areas of China can reach 1 meter. If its snout is fully extended, it is even longer than its body[1]!
Main features
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Belonging to the lower levelinvertebrateThere is a reversible muscular snout in the snout cavity at the front and back of the alimentary canal.The snout is tubular, and many aquatic species have needles on their snouts for predation;The snout of terrestrial species is used for rapid movement.At the mouth with vascular system and digestive tractanusAmong the separated animals, the Nexus is the simplest group.The body is usually long and thin, and it is often extremely stretched during exercise.Most species are less than 20 cm (8 inches) in length, but have huge longitudinal groovesnemertean(Lineus longissimus) up to 30 meters (100 feet) long.The species swimming in deep water are wide and flat, with finsAppendage。Newworms are usually monochromatic, and some species have distinctive patterns of stripes, bands, spots or geometric shapes.
Nugulates
living environment
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Nugulates are mostly marine, mostly distributed in coastal waters of temperate zone (especially the Mediterranean region and Europe), and can inhabit under rocks and aquatic plants, or drill into sediment.A few live in deeper waters or open seas.It is not common in the tropics and subtropics, but also distributed in the poles.CorpusclenemerteanThe genus (Prostoma) is distributed in fresh water all over the world.Geonemertes is terrestrial and distributed in the subtropical zone (especially in Australia and New Zealand).CarnivorousTo live or dead animals, especiallyAnnelidaFor food.Entangling their prey with kisses, sometimes injecting toxic substances.Most species are dioecious,In vitro fertilization。ZygoteThe development process ofFlatfish, circular animals and molluscs are similar.Usually directlydevelopment, no larval stage;Some are in larval stage.There are two types of larvae: the more common one is the free swimming cap like larvae;The other kind of larva looks like an adult, called Desor's larva.Monoecious or hermaphroditic in the genera Oncomelania and Geonema.
features
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nemerteanAll haveRegenerative capacitySome can be broken into many pieces, and then grow into a complete individualAsexual reproduction。Nugulates andFlatfishProximal margin;embryonic developmentThe form is similar and the basic system is the same.However, the digestive tract of Newworms is complete and has a circulatory system.It is generally believed that the newulate is the highestCoelomatous animalA separate door.The important characteristics of the newulate animals for classification are the relative position of the brain and mouth, whether there is a small needle on the snout, and the relative position of the lateral nerve and muscle layer.Some ringsFauna(Annelida)'sBlood worm(bloodworm) is also called kiss worm.
systemCoelomorph，ProtocoelomClass,ProtostomeOne door.Also callednemerteanClass.The soft tissue is very developed, so the body is soft.The back and abdomen are flat, and the front and back grow in a tie shape, without division.The body surface is covered by cilia and secretes a lot of mucus.Alimentary canalVery developed, straight,midgutThere are multiple side cysts in the middle, and the rear end hasanus。The back of the alimentary canal is covered with the unique kiss of the family, which is hidden in the kiss sheath.The front end of the body can be turned out for free access.The excretory organs areProtonephric duct。It has a closed vascular system.The nervous system is mainly composed of the brain and a pair of left and right nerve cords.Androgynous.GonadIt is cystic and mostly interacts with the side sacs of the midgut.The gaps between the body wall and internal organs are filled with soft tissue, and the only gap in the body is between the kiss and the kiss sheathRostral cavity, NoneCoelom。PedigreePlatyhelminthesThe door behind it.However, it is also included in the broad Platyhelminthes phylumPlanarian、TrematodaandTaeniaCollectively called trueflatwormEuplathelmintbes, and willnemerteanClass is called Rhynchocoela.
Nugular animal body is elongated into a belt shape, symmetrical from left to right.There is a long front of digestive tractCaecum, extending backward from the back, and containing the snout tube, it is called "snout cavity".The snout tube has a muscle bundle connected with the end of the snout cavity, which can be turned out of the body or retracted into the snout cavity.Most marine products, a few in fresh water, wet soil, and some parasitic[1]。
