Cnidarians - coelenterates

Acropora robusta

Acropora robusta coral is a species of acroporid coral found in the Red Sea, the Gulf of Aden, the southwest and northern Indian Ocean, the central Indo-Pacific, Australia, Southeast Asia, Japan, the East China Sea and the oceanic west and central Pacific O...

Black Turret coral - Tubastraea micranthus

Black Turret coral, Tubastraea micranthus, also known as sun coral or sun polyps, is a genus of coral in the phylum Cnidaria. It is a cup coral in the Dendrophylliidae family. Sun corals belong to a group of corals known as large-polyp stony corals. ......

Christmas tree hydroid - Pennaria disticha

Pennaria disticha, also known as the Christmas tree hydroid, is a species of athecate hydroid in the family Pennariidae. Colonies are common in the Mediterranean Sea growing on rocks close to the surface. This species has been used in research into prey ...

Christmas tree hydroid - Pennaria disticha

L'idroide piumato (Pennaria disticha Goldfuss, 1820) è un idrozoo della famiglia Pennariidae, diffuso nel mar Mediterraneo. È una forma polipoide sessile che dà vita a fitte colonie ramificate, con accrescimento verticale, alte 10-30 cm, con verticilli di ...

Coral loaf - Cladocora caespitosa

Cladocora caespitosa, commonly known as Coral loaf or "cushion coral", is a stony coral of the subclass Hexacorallia, phylum Cnidarian. This species forms the only true coral reef in the Mediterranean Sea. ...

Dendronephthya hemprichi

Dendronephthya hemprichi è un corallo molle comune che troviamo dal Mar Rosso al Pacifico Occidentale. Di solito è rosa o arancione con tronco trasparente e cresce fino a 70 cm. Questa particolare specie del Dendronephthya ...

False black coral - Savalia savaglia

Savalia savaglia is a colonial antozoo whose appearance resembles that of the common sea fans, but the polyps that constitute it differ greatly from those of the latter is for the structure to the size. Savalia savaglia falso corallo nero antozoo coloniale...

Flowerpot coral - Goniopora lobata

Il Corallo Margherita, Goniopora lobata, spesso chiamato Corallo a vaso di fiori, è un genere di corallo pietroso coloniale che si trova nelle lagune e in condizioni di acqua torbida. Goniopora ha numerosi polipi simili a margherite che si estendono ...

Jellyfish

The jellyfish is a planktonic animal, marine prevalence, belonging to the phylum Cnidaria, which together with the Ctenophores formed what were once Coelenterates. ...

Aequorea forskalea

Aequorea forskalea (Péron & Lesueur, 1810) è una medusa della famiglia Aequoreidae. Aequorea forskalea medusa della famiglia Aequoreidae ...

Australian spotted jellyfish - Phyllorhiza punctata

This young punctate jellyfish missing its tentacles is an Australian spotted jellyfish - Phyllorhiza punctata. Surely the tentacles have been eaten by natural predators. The presence of this jellyfish in the southern Mediterranean is more and more frequented ...

Barrel Jellyfish - Rhizostoma pulmo

Il polmone di mare (Rhizostoma pulmo Macri, 1778) è una scifomedusa della famiglia delle Rhizostomatidae. Polmone di mare Rhizostoma pulmo scifomedusa intotheblue.it ...

Cigar jellyfish - Olindias phosphorica

Olindias phosphorica is a species of jellyfish originating from the central Atlantic, and from the Mediterranean Sea, including Malta. Olindias phosphorica Medusa Cigar jellyfish intotheblue.it ...

Mediterranean Cassiopeia or Fried Egg jellyfish - Cotylorhiza tuberculata

The Mediterranean Cassiopeia or Fried Egg jellyfish (Cotylorhiza tuberculata Macri, 1778) is one of scifomedusa cepheidae family, common in the Mediterranean Sea. Cassiopea mediterranea Cotylorhiza tuberculata scifomedusa Cepheidae ...

Purple jellyfish - Pelagia noctiluca

Pelagia noctiluca, conosciuta comunemente come medusa luminosa, è una medusa della famiglia Pelagiidae. Pelagia noctiluca medusa luminosa famiglia Pelagiidae ...

Sea raft - Velella velella

Velella è un genere monospecifico di idrozoi della famiglia Porpitidae. La sua unica specie conosciuta è la Velella velella, un idrozoo galleggiante che galleggia sulla superficie dell'oceano aperto. ...

Leptogorgia gorgonian - Leptogorgia sarmentosa

Leptogorgia belongs to the philum of the Cnidarians, to the class of Anthozoans, to the subclass of the Octocorals and to the order of the Gorgonians. ...

Lobactis scutaria

Lobactis è un genere di corallo a piastre o corallo fungo della famiglia Fungiidae. Il genere è monotipico con un'unica specie: Lobactis scutaria , che si trova nella dell’Indo-Pacifico. E’ un corallo solitario, non coloniale, che vive libero e non at...

Madreporaria - Scleractinia

La Scleractinia, chiamata anche corallo sassoso o corallo duro, è un animale marino nel Cnyidaria che si costruisce uno scheletro duro. I singoli animali sono noti come polipi ...

Red coral or precious coral - Corallium Rubrum

Red coral, precious coral (Linnaeus, 1758), is a octocorallo of Coralliidae family, common in the Mediterranean and eastern Atlantic. Corallo Rosso Red Coral Corallium Rubrum Cnidari Cnidarians ...

Red gorgonian - Paramuricea clavata

Paramuricea clavata, the violescent sea-whip, is a species of colonial soft coral in the family Plexauridae. It is found in shallow seas of the north-eastern Atlantic Ocean and the north-western Mediterranean Sea as well as Ionian Sea. ...

Sarcophyton ehrenbergi

Sarcophyton ehrenbergi,  Marenzeller 1886,  è un ottocorallo della famiglia Alcyoniidae. La famiglia comprende ottocoralli coloniali, con colonie di forma arborescente o lobulata, in cui i polipi sono immersi in un robusto cenenchima di consistenza si...

Sarcophyton trocheliophorum

Sarcophyton trocheliophorum, Marenzeller 1886,  è un ottocorallo della famiglia Alcyoniidae. La famiglia comprende ottocoralli coloniali, con colonie di forma arborescente o lobulata, in cui i polipi sono immersi in un robusto cenenchima di consistenza s...

Scarlet coral - Balanophyllia Europea

La Balanophyllia europea, conosciuta comunemente come madrepora solitaria, è una madrepora della famiglia Dendrophylliidae. Madrepora Solitaria Balanophyllia europea intotheblue.it ...

Sea anemone - Actinaria

Sea anemones are a group of marine, predatory animals of the order Actiniaria. They are named after the anemone, a terrestrial flowering plant, because of the colourful appearance ...

Anemone - Anemonia sulcata

Anemonia sulcata (Pennant, 1777), known as Venus's hair, is a celenterate antozoo of the family Actiniidae. Anemone Anemonia sulcata Celenterato antozoo cnidari cnidarians ...

Attinia di sabbia o Anemone di rena - Condylactis aurantiaca

Questo anemone, l'attinia di sabbia o attinia di rena o anemone di sabbia, è una specie di anemone piuttosto diffusa nel Mar Mediterraneo ma difficile da incontrare dal momento che popola quasi esclusivamente fondali sabbiosi e renosi o fangosi ...

Beadlet anemone - Actinia Equina

Actinia equina (Linnaeus, 1758) comunemente nota come pomodoro di mare, è un cnidario antozoo della famiglia Actiniidae, che abita la zona intertidale, fino a pochi metri di profondità. ...

Cylindrical anemone - Cerianthus Membranaceus

Cerianthus membranaceus, the cylindrical anemone or colored tubular anemone, is a species of large, tubiform anemone of the Cerianthidae family. It originates from the Mediterranean Sea and adjacent parts of the northeastern Atlantic Ocean. Cerianthus...

Fat anemone - Cribrinopsis crassa

L' Anemone grosso, Cribrinopsis crassa (Andrès, 1881) è un anemone di mare della famiglia Actiniidae, endemico del mar Mediterraneo. Cribrinopsis crassa Fat anemone Anemone grosso Actiniaria intotheblue.it ...

Hermit Crab Anemone - Calliactis parasitica

Calliactis parasitica is a species of sea anemone associated with hermit crabs. It lives in the eastern Atlantic Ocean and the Mediterranean Sea at depths between the intertidal zone and 60 m (200 ft). It is up to 10 cm × 8 cm (3.9 in × 3.1 in) large, w...

Magnificent sea anemone - Heteractis magnifica

Heteractis magnifica, also known by the common names magnificent sea anemone or Ritteri anemone, is a species of sea anemone belonging to the Stichodactylidae family native to the Indo-Pacific area. ...

Trumpet anemone - Aiptasia mutabilis

Trumpet anemone (Aiptasia mutabilis Gravenhorst, 1831) is an antozoo belonging to the Aiptasiidae phylum cnidarians in the Mediterranean Sea ...

Sea pen - Pennatula phosphorea

Pennatula phosphorea  is a octocoral in the family Pennatulidae.  Pennatula is a genus of sea pens in the family Pennatulidae. The genus contains several bioluminescent species, including Pennatula rubra, Pennatula phosphorea and Pennatula aculeata. Sea pe...

Sea Whip coral - Subergorgia hiksoni

Gorgonia a Ventaglio gigante - Sea Whip coral - Subergorgia hiksoni - intotheblue.it - Gorgonia Ventaglio gigante Subergorgia hiksoni intotheblue.it ...

Staghorn coral - Acropora cervicornis

Staghorn coral (Acropora cervicornis) is a branching, stony coral with cylindrical branches ranging from a few centimetres to over two metres in length and height. ...

Table Coral - Acropora pulchra

Acropora pulchra, is a species of coral belonging to the Acroporidae family . It lives in shallow waters in the coral reefs of the Western Indo-Pacific Ocean. ...

Venus fan - Gorgonia Flabellum

Gorgonia flabellum, also known as the Venus fan, Venus sea fan, common sea fan, West Indian sea fan, and purple gorgonian seafan, is a species of sea fan, a sessile colonial soft coral. ...

White gorgonian - Eunicella singularis

White gorgonian Eunicella singularis, is a gorgonian typical of the Mediterranean Sea, grows on rocky, muddy and detrital bottoms and often colonizes bottoms that have undergone stress caused by the change in water temperatures or damage caused by trawling,...

White Gorgonian - Eunicella verrucosa

Eunicella verrucosa, Gorgonia Bianca, ampia gorgonia, gorgonia rosa o gorgonia verrucosa, è una specie di "corallo molle" coloniale gorgoniano della famiglia Gorgoniidae, phylum Cnidari. ...

White sea pen White Pennatula - Pteroeides spinosum

In this post we talk about "White Sea Pen" White Pennatula Pteroeides spinosum, a rare soft coral of the Mediterranean Sea that belongs to the philum of the Cnidarians, to the class of Anthozoans, to the subclass of the Octocorals and to the order of...

Yellow cluster anemone - Parazoanthus axinellae

Yellow cluster anemone (Parazoanthus axinellae Schmidt, 1862) is a zoanthid coral found on the southern Atlantic coasts of Europe and in the Mediterranean Sea. ...

Yellow gorgonian or Yellow sea whip - Eunicella Cavolinii

Eunicella cavolini, commonly known as the yellow gorgonian or yellow sea whip, is a species of colonial soft coral in the family Gorgoniidae. It is native to parts of the eastern Atlantic Ocean and most of the Mediterranean Sea, where it is a common ...

Yellow scroll Coral - Turbinaria reniformis

Yellow scroll Coral, Turbinaria reniformis, is a species of colonial stony coral in the family Dendrophylliidae. It is native to the Indo-Pacific region. The International Union for Conservation of Nature has rated its conservation status as being “vulnerable” due ...

Cnidarians, or coelenterates, are a phylum of animals radially symmetrical, diblasteri and water. Cnidari Celenterati Cnidarians coelenterates celenteron

Anatomy and Physiology

Their body can be schematically shown as a lot, with a single opening, surrounded by tentacles, which acts as a mouth but also serves to expel carbon dioxide and waste substances. The tentacles are used to grab prey. The internal cavity, said celenteron, is a true gastrovascular cavity, which extends in part also in the tentacles.

The celenteron performs two functions:

1. digestive, as there are poured digestive juices produced by the cells which cover it.
2. vascular, since the water that fills it comes close enough to all tissues of the body, providing nutrients and oxygen and removing carbon dioxide and waste substances.

The structural model of Coelenterates is expressed in two forms: polyp and Jellyfish.

Polyps are normally sessile, or fixed to a solid support, and then benthic, with the mouth opening upwardly.

Jellyfish are floating, with the mouth opening downwards. The body of the jellyfish, because of its shape, is said umbel; the aboral part of the umbrella (normally facing upward), convex, is said esombrella, whereas the oral part (normally facing downwards), concave, is said subombrella; This extends to the center in a tubuliforme structure more or less elongated said handlebars, ending with the mouth. The tentacles usually radiate from the umbrella margin (that is, the border between esombrella and subombrella). They are part of the plankton, since it does not actively swimming in the horizontal direction, although they can contract the umbrella to move vertically. In the outer layer of the body (epidermis) are differentiated cells. Muscle cells, able to contract and ensure the movement and body tone. The nerve cells, able to transmit stimuli. Polyps in the nervous system is a network, not a particular organization. In jellyfish there is some hierarchy, with main nerve rays that depart from umbrella top. Between the outer layer and the inner which lines the celenteron (gastrodermis) there is a gelatinous layer, the mesoglea, acellular least in the most primitive forms.

Polyps in the only ways these are the tact and sensitivity to substances dissolved in the water.

In the jellyfish we find two real sense organs. The statocisti, a vesicle internally covered with hair cells and containing one statolito, a mineral body secreted by the animal. It allows the jellyfish to react to the changes in position relative to the vertical, because in that case the statolito pressed on different parts of the wall. A eyespot, sensitive to the light intensity, which allows the animal to adjust its depth according to the intensity of the light.

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Biology

Supply

The diet of cnidarians is carnivorous: they feed on copepods and small fish, more juveniles feed on fitoflagellati and rotifers. The abundance of food is important for the development of cnidarians as it is the main element that the strobilazione of hydroids and scyphozoans take place.

The prey is captured with poison inoculation through cnidocysts, including all species of the phylum are provided and subsequently introduced into the internal cavity to be digested. The digestion is partly extracellular and intracellular part. The extracellular digestion occurs because of digestive enzymes produced in celenteron. Intracellular digestion is obtained from the same cells that engulf and digest internally small food particles. The digestion residues are then expelled from the external environment mouth.

Reproduction Sexual reproduction is present in all species; that asexual, mostly by budding, it generally has in polyps.

There are species in which it has alternation of generations between polyps and jellyfish. In these cases, the jellyfish reproduce sexually by producing gametes are expelled from the mouth. Fertilization takes place in the water; from the fertilized egg develops ciliated larva, called planula, that at some point lies in a prime area and begins to grow giving the embryo. The latter reproduces asexually for strobilazione giving rise to jellyfish.

Systematic

The phylum Cnidaria is generally divided into 6 classes, each of which comprising a wide diversity of organisms share a similar life cycle and by the same elements of internal symmetry. According to Petersen (and later Bouillon), the cnidarians are divided into two sub-phylum: the Anthozoaria who only phase polypoid and the Medusozoa who is the phase of jellyfish.

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• Classe Anthozoa (Antozoi)
  • Sottoclasse Hexacorallia (Esacoralli)
    • Ordine Actiniaria
    • Ordine Antipatharia
    • Ordine Ceriantharia
    • Ordine Corallimorpharia
    • Ordine Rugosa †
    • Ordine Scleractinia
    • Ordine Zoantharia
  • Sottoclasse Octocorallia (octocoralli)
    • Ordine Alcyonacea
    • Ordine Helioporacea
    • Ordine Pennatulacea
• Classe Hydrozoa (Idrozoi)
  • Sottoclasse Hydroidolina o Hydroida
    • Ordine Anthoathecata
    • Ordine Leptothecata
    • Ordine Siphonophora
  • Sottoclasse Trachylinae o Automedusae
    • Ordine Actinulida
    • Ordine Limnomedusae
    • Ordine Narcomedusae
    • Ordine Trachymedusae
• Classe Scyphozoa (Scifozoi)
  • Sottoclasse Discomedusae
    • Ordine Semaeostomea
    • Ordine Rhizostomea
  • Ordine Coronatae
• Classe Cubozoa (Cubozoi)
  • Ordine Carybdeida o Cubomedusae
  • Ordine Chirodropida
• Classe Staurozoa
  • Ordine Conulatae 
  • Ordine Stauromedusae
• Classe incertae sedis
  • Famiglia Tesseranthidae
• Classe Polypodiozoa (filogenetica incerta nel 2014)
  • Ordine Polypodiidea

(Wikipedia)