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Porifera (Sponges)

Porifera are, in the great majority, filter feeders. Their surface is pierced by a multitude of small pores through which water enters (ostia), and fewer and larger holes, the oscules, through which water exits (poriferous: from the Greek por- = passage). They generally have a skeleton formed of siliceous or calcareous spicules and / or spongin fibres.

Demosponges

Demosponges are sponges whose skeleton, when present, is composed of siliceous spicules and / or spongin fibres. The majority of sponges have this feature.

Adreus fascicularis

Calcarea (calcareous sponges)

Calcareous sponges have a skeleton composed of calcareous spicules. They live in marine waters at depths not exceeding 100 meters.

Sycon ciliatum

Porifera (introduction)

These pages present the Porifera Phylum, their biology and their anatomy using clear, concise text with numerous diagrams and photographs.

Aplysina aerophoba

Bibliographie et sites de référence

Consultez les références bibliographiques concernant les Porifères, parutions scientifiques, guides naturalistes, liens internet utilisés en référence pour la réalisation de ce chapitre consacré aux Porifères.

Bibliographie

Cnidarians

Cnidarians are animals with radial symmetry. They have a single orifice, the mouth which is surrounded by tentacles.
They have stinging cells, cnidoblasts, which allow them to neutralize their prey. This characteristic is at the origin of their name (from the Greek cnid- = nettle).

Hydrozoans

Hydrozoans are Cnidarians which generally alternate a sessile phase (polyp) and a pelagic phase (jellyfish). They can be solitary or colonial. The majority are marine but there are also freshwater (hydra) species.

Tubularia indivisa

Scyphozoans and Staurozoans

Scyphozoans or true jellyfish are pelagic Cnidarians. Staurozoans are small sessile jellyfish that adhere to algae by an extension of the umbrella.

Chrysaora hysoscella

Anthozoans

Anthozoans have no jellyfish phase. They include: Octocorals, polyps with 8 tentacles (soft corals, gorgonians and sea pens). Hexacorals, polyps with 6 or multiple of 6 tentacles (sea anemones and corals).

Actinothoe sphyrodeta

Les Cnidaires (présentation)

Ces pages vous présentent l'embranchement des Cnidaires, leur biologie et leur anatomie à l'aide d'un texte clair et concis aggrémenté de nombreux schémas et photographies.

Paramuricea clavata

Bibliographie et sites de référence

Consultez les références bibliographiques concernant les Cnidaires, parutions scientifiques, guides naturalistes, liens internet utilisés en référence pour la réalisation de ce chapitre consacré aux Cnidaires.

Bibliographie

Ctenophores

Ctenophores

Ctenophores are solitary and pelagic animals. Their transparent body reminds of jellyfish but they do not have stinging cells but adhesive cells, colloblasts. They have up to 8 rows of luminescent hair plates resembling combs (from the Greek ctenos = comb) that allow them to move.

Ctenophores

Ctenophores are solitary and pelagic animals. Their transparent body is reminiscent of jellyfish but they do not have stinging cells but adhesive cells, the colloblasts.

Cestum veneris

Bibliographie et sites de référence

Consultez les références bibliographiques concernant les Cténophores, parutions scientifiques, guides naturalistes, liens internet utilisés en référence pour la réalisation de ce chapitre consacré aux Cténophores.

Bibliographie

Platyhelminthes

Platyhelmintes or flatworms are either parasitic (tapeworm, liver fluke) or aquatic (planar) animals. Their body is elongated, thin and without appendage. Their digestive tract has only one ventral opening, the mouth.

Planar flatworms

Planars (Turbellaridae) are aquatic flatworms, swimmers or crawlers. They live in marine environment and in fresh water.

Prostheceraeus vittatus

Bibliographie et sites de référence

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Bibliographie

Molluscs

Molluscs are animals with a soft body (from the Latin mollis = soft). They are generally protected by a shell which can be simple, with plates or with two valves. They have gills or lungs and a muscular foot, transformed in cephalopods into tentacles.

Polyplacophoran molluscs (chitons)

Chitons are molluscs with an oval and flattened shell, made up of 8 articulated plates.

Chaetopleura angulata

Prosobranch gastropods

These gastropods have a spiral outer shell and have the common characteristic of having gills at the front of the heart.

Charonia lampas

Opistobranch gastropods

These gastropods have the common characteristic of having gills at the back of the heart. Some have a shell which is generally hidden by the mantle (sea hares), others have no shell at all (nudibranchs).

Diaphorodoris papillata

Cephalopods

Cephalopods have around eight to ten tentacles with suction cups around their heads and well developed eyes. They have an internal shell (cuttlefish and squid) or no shell (octopus).

Loligo vulgaris

Bivalves

Bivalves or lamellibranchs have an outer shell with two articulated valves and gills in the form of lamellae.

Dosinia exoleta

Scaphopods

Scaphopods have a tubular shell open at each end.

Antalis vulgaris

Les Mollusques (présentation)

Ces pages vous présentent l'embranchement des Mollusques, leur biologie et leur anatomie à l'aide d'un texte clair et concis aggrémenté de nombreux schémas et photographies.

Colpodaspis pusilla

Bibliographie et sites de référence

Consultez les références bibliographiques concernant les Mollusques, parutions scientifiques, guides naturalistes, liens internet utilisés en référence pour la réalisation de ce chapitre consacré aux Mollusques.

Bibliographie

Annelids

Annelids are worm-shaped animals with bodies segmented into several rings that repeat identically. (Ann- from Latin annullus = ring). Only the segments of the front part (the head) and the rear are different.

Errantia annelids

Errantia annelids are segmented worms that live freely on sand, mud or among rocks. They have parapods and often well developed bristles that allow them to move.

Polynoe scolopendrina

Sedentaria annelids

Sedentaria annelids are worms that secrete calcareous, chitinous or mucous tubes fixed on rocks, weeds, shells or buried in sand or mud.
Occasionally, they can get out of their tube and move around.

Bispira volutacornis

Bibliographie et sites de référence

Consultez les références bibliographiques concernant les Annélides, parutions scientifiques, guides naturalistes, liens internet utilisés en référence pour la réalisation de ce chapitre consacré aux Annélides.

Bibliographie

The Other Worms

Nemerteans and Sipunculans are vermiform animals with very different characteristics.
Select each of these groups for a short description.

Nemerteans

Nemerteans are ribbon worms with a non-segmented flattened and ciliated body. Mainly marine, they are found among rocks or under stones. (Nemerteans from the Greek nem- = thread, filament).

Paradrepanophorus crassus

Sipunculans

Sipunculans are non-segmented worm-like organisms that have a retractable part at the front, called introvert which allows them to bury themselves in the sediment. The mouth lies at the end of the introvert.

Golfingia-(golfingia)-elongata

Bryozoans

Bryozoans

Bryozoans are animals composed of an outer cuticle and squeleton, the cystid, and a fleshy body, the polypid. This one carries a crown of tentacles called lophophore which surrounds the mouth. The U-shaped intestine opens outside the lophophore. (from the Greek bryon = moss).

Bryozoans

Bryozoans are filter feeders living in more or less calcified colonies of encrusting, bushy or erect forms. They live mainly in marine environment, some species live in fresh water.

Reteporella grimaldii

Bibliographie et sites de référence

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Bibliographie

Other lophophorates

Lophophorates are animals bearing a lophophore that is a ring of ciliated tentacules surrounding the mouth. Bryozoans (see above), Brachiopods and Phorinids possess this particular feeding organ.
Select each of these groups for a short description.

Brachiopods (lamp shells)

Brachiopods are sessile marine animals attached to the substrate by a pedicle. They have a shell with two asymmetric valves containing the lophophore.

Megerlia truncata

Phoronids (horseshoe worms)

Phoronids are exclusively marine animals. Their vermiform body is terminated by a lophophore and they secrete a chitinous tube in which they live.

Phoronis hippocrepia

Crustaceans and other Marine Arthropods

Crustaceans and other marine arthropods

Crustaceans and other arthropods are animals with a segmented body and articulated legs (Arthropoda from Greek arthronn = joint and podos = foot). They have a chitinous exoskeleton, the carapace. Fixed to substratum or free, they live in aquatic (fresh and salty water) or terrestrial environments.

Other marine arthropods

Nymphon gracile

Crustaceans

Crustaceans are arthropods with mandibles and antennae. They include the Decapods (crabs, lobsters, shrimps...), isopods (sea slater...), amphipods (sandhopper...), cirripedes (barnacles). They live in fresh or salt water or on land.

Cancer pagurus

Echinoderms

Echinoderms have a pentaradial symmetry, that is to say that their body can be divided into five identical parts (with some exceptions!).
They are covered with spines, numerous in sea urchins or more sparse in sea cucumbers, hence their name Echinoderms (from the Greek echino- = thorny and derm- = skin).

Crinoids (Sea lilies and feather stars)

Feather stars have at least five pairs of articulated, thin and pinnate arms. The central disc is small and has cirri on its underside that allow them to cling to the substratum.

Antedon bifida

Asteroids (Starfish)

Starfish have a large central disc and at least five thick, non-articulated arms.

Astropecten irregularis

Ophiuroids (Brittle stars)

Brittle stars always have five fine and articulated arms, provided with more or less long spines and starting from a central disc.

Ophiothrix fragilis

Echinoids (Sea urchins)

Sea urchins have a generally spherical external skeleton called test and composed of a multitude of small calcareous plates. The surface is covered with many spines.

Sphaerechinus granularis

Holothurians (Sea cucumbers)

Sea cucumbers have a soft, elongated, cylindrical body. The mouth is surrounded by more or less developed tentacles. The body is traversed by five longitudinal rows of retractable podias.

Holothuria (Roweothuria) poli

Bibliographie et sites de référence

Consultez les références bibliographiques concernant les Echinodermes, parutions scientifiques, guides naturalistes, liens internet utilisés en référence pour la réalisation de ce chapitre consacré aux Echinodermes.

Bibliographie

Tunicates

Tunicates are solitary or colonial animals that are sessile (sea squirts) or pelagic (salps). Their body is surrounded by a more or less cartilaginous tunic (from the Latin tunica = tunic). Their tadpole larvae have a central axis or chorde in the tail, a draft of the spine, an axis which they generally lose at the adult stage.

Aplousobranch sea squirts

Aplousobranchs group sea squirts (sessile tunicates) whose body is divided into 2 or 3 distinct parts (thorax, abdomen and post-abdomen). In this group, there are social and compound ascidians.

Aplidium elegans

Phlebobranch sea squirts

Phlebobranchs group sea squirts (sessile tunicates) with undivided bodies and gonads on one side near the digestive tract. In this group, there are solitary and social ascidians.

Ascidiella aspersa

Stolidobranch sea squirts

Stolidobranchs group sea squirts (sessile tunicates) with undivided bodies. They have complex gills and their gonads are near the pharynx. In this group, there are solitary, social and compound ascidians.

Dendrodoa grossularia

Larvaceans and Thaliaceans

These two groups bring together pelagic tunicates.
Larvaceans resemble the tadpole larva of ascidians.
Thaliaceans (salps) have a cylindrical and transparent body and are solitary and colonial.

Pegea confoederata

Les Tuniciers (présentation)

Ces pages vous présentent l'em-branchement des Tuniciers, leur biologie et leur anatomie à l'aide d'un texte clair et concis aggrémenté de nombreux schémas et photographies.

Astropecten irregularis

Bibliographie et sites de référence

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Bibliographie

Fishes

Fishes

Cartilaginous fishes

Raja clavata

Bony fishes

Spondyliosoma cantharus

Bibliographie et sites de référence

Consultez les références bibliographiques concernant les Poissons, parutions scientifiques, guides naturalistes, liens internet utilisés en référence pour la réalisation de ce chapitre consacré aux Poissons.

Bibliographie

Red seaweeds

Red seaweeds

Red seaweeds

Red seaweeds

Delesseria sanguinea

Bibliographie et sites de référence

Consultez les références bibliographiques concernant les Algues, parutions scientifiques, guides naturalistes, liens internet utilisés en référence pour la réalisation de ce chapitre consacré aux Algues.

Bibliographie

Green seaweeds

Green seaweeds

Green seaweeds

Green seaweeds

Ulva sp.

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Bibliographie

Brown seaweeds

Brown seaweeds

Brown seaweeds

Brown seaweeds

Ascophyllum nodosum

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Consultez les références bibliographiques concernant les Algues, parutions scientifiques, guides naturalistes, liens internet utilisés en référence pour la réalisation de ce chapitre consacré aux Algues.

Bibliographie

Marine phanerogams

Marine phanerogams

Marine phanerogams

Marine phanerogams (seagrass, eelgrass)

Posidonia oceanica

Bibliographie et sites de référence

Consultez les références bibliographiques concernant les Algues, parutions scientifiques, guides naturalistes, liens internet utilisés en référence pour la réalisation de ce chapitre consacré aux Algues.

Bibliographie

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