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Echinocardium Cordatum
''Echinocardium cordatum'', also known as the common heart urchin or the sea potato, is a sea urchin in the family (biology), family Loveniidae. It is found in sub-tidal regions in the NE Atlantic. Other un-named species have been identified as this species from temperate seas around the world. It lives buried in the sandy sea floor. Description The sea potato is a heart-shaped urchin clothed in a dense mat of furrowed yellowish spines which grow from tubercles and mostly point backwards. The upper surface is flattened and there is an indentation near the front. This urchin is a fawn colour but the Test (biology), tests that are found on the strandline have often lost their spines and are white. During life, the spines trap air which helps prevent asphyxiation for the buried urchin. The Ambulacrum (anatomy), ambulacra form a broad furrow in a star shape extending down the sides of the test. There are two series each of two rows of tube feet. The test reaches from six to nine cent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thomas Pennant
Thomas Pennant (14 June Old Style, OS 172616 December 1798) was a Welsh natural history, naturalist, traveller, writer and antiquarian. He was born and lived his whole life at his family estate, Downing Hall near Whitford, Flintshire, in Wales. As a naturalist he had a great curiosity, observing the geography, geology, plants, animals, birds, reptiles, amphibians and fish around him and recording what he saw and heard about. He wrote acclaimed books including ''British Zoology'', the ''History of Quadrupeds'', ''Arctic Zoology'' and ''Indian Zoology'' although he never travelled further afield than continental Europe. He knew and maintained correspondence with many of the scientific figures of his day. His books influenced the writings of Samuel Johnson. As an antiquarian, he amassed a considerable collection of art and other works, largely selected for their scientific interest. Many of these works are now housed at the National Library of Wales. As a traveller he visited Sco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pelagic Zone
The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the surface of the sea and the bottom. Conditions in the water column change with depth: pressure increases; temperature and light decrease; salinity, oxygen, micronutrients (such as iron, magnesium and calcium) all change. Marine life is affected by bathymetry (underwater topography) such as the seafloor, shoreline, or a submarine seamount, as well as by proximity to the boundary between the ocean and the atmosphere at the ocean surface, which brings light for photosynthesis, predation from above, and wind stirring up waves and setting currents in motion. The pelagic zone refers to the open, free waters away from the shore, where marine life can swim freely in any direction unhindered by topographical constraints. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urothoe Marina
''Urothoe marina'' is a species of small marine amphipod crustaceans in the family Urothoidae. It is found on and burrowing in coarse sediments in shallow coastal waters off northwestern Europe. Description ''U. marina'' is about long, crescent-shaped and a yellowish-white colour. It is laterally compressed and normally lies on one side. The head is fused with the thorax and bears two unequal sized antennae. In the male, the lower antenna is as long as the body but in the female, it is only just longer than the upper one. The upper antenna has a short side branch. The stalked eyes are black. Those of the male are very large while the female has smaller, oval eyes. The thorax consists of eight somites each with its own appendages and some setae. The posterior pereiopods are wider than they are long and have feathery setae. The uropods are densely hairy and the short telson has a single spine and a few setae. Distribution ''U. marina'' occurs off the coasts of northwest Europe. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amphipoda
Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from and are mostly detritivores or scavengers. There are more than 9,900 amphipod species so far described. They are mostly marine animals, but are found in almost all aquatic environments. Some 1,900 species live in fresh water, and the order also includes the terrestrial sandhoppers such as ''Talitrus saltator''. Etymology and names The name ''Amphipoda'' comes, via New Latin ', from the Greek roots 'on both/all sides' and 'foot'. This contrasts with the related Isopoda, which have a single kind of thoracic leg. Particularly among anglers, amphipods are known as ''freshwater shrimp'', ''scuds'', or ''sideswimmers''. Description Anatomy The body of an amphipod is divided into 13 segments, which can be grouped into a head, a thorax and an abdomen. The head is fused to the thorax, and bears two pairs of antennae and one pair of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Byssus
A byssus () is a bundle of filaments secreted by many species of bivalve mollusc that function to attach the mollusc to a solid surface. Species from several families of clams have a byssus, including pen shells (Pinnidae), true mussels (Mytilidae), and Dreissenidae. Filaments Byssus filaments are created by certain kinds of marine and freshwater bivalve mollusks, which use the byssus to attach themselves to rocks, substrates, or seabeds. In edible mussels, the inedible byssus is commonly known as the "beard", and is removed before cooking. Many species of mussels secrete byssus threads to anchor themselves to surfaces, with families including the Arcidae, Mytilidae, Anomiidae, Pinnidae, Pectinidae, Dreissenidae, and Unionidae. Mechanics The byssus, or byssal complex, is composed of multiple extracellular collagenous threads that are placed radially by the mussel from a central stem. Each thread is composed of three regions: a corrugated proximal region close to the mussel b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commensalism
Commensalism is a long-term biological interaction (symbiosis) in which members of one species gain benefits while those of the other species neither benefit nor are harmed. This is in contrast with mutualism, in which both organisms benefit from each other; amensalism, where one is harmed while the other is unaffected; parasitism, where one is harmed and the other benefits, and parasitoidism, which is similar to parasitism but the parasitoid has a free-living state and instead of just harming its host, it eventually ends up killing it. The commensal (the species that benefits from the association) may obtain nutrients, shelter, support, or locomotion from the host species, which is substantially unaffected. The commensal relation is often between a larger host and a smaller commensal; the host organism is unmodified, whereas the commensal species may show great structural adaptation consistent with its habits, as in the remoras that ride attached to sharks and other fishes. Remo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tellimya Ferruginosa
''Tellimya ferruginosa'' is a species of small marine bivalve mollusc in the family Lasaeidae. It is found on the eastern side of the Atlantic Ocean. Bivalves are molluscs with a body compressed between two usually similar shell valves joined by an elastic ligament. There are teeth at the edge of the shell, and the animal has a muscular foot, gills, siphons, mouth and gut and is surrounded by a mantle inside the shell. Taxonomy The genus ''Tellimya'' used to be included in the family Montacutidae but has now been transferred to Lasaeidae. Montagu originally described this species as ''Montacuta ferruginosa'' but it is currently placed in the genus ''Tellimya''. Description This mollusc grows to up to eight millimetres in length and has a fragile, thin glossy shell. It is broadly oval in shape with the umbo or beak and the hinge being in the posterior half. The ligament joining the two valves is internal. The right valve has a single cardinal tooth which is a continuation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chamelea Gallina
''Chamelea gallina'' is a species of small saltwater clam, a marine bivalve in the family Veneridae, the venus clams. Taxonomy Carl Linnaeus originally described ''Venus gallina'' from the Mediterranean Sea in 1758. It was not clear whether da Costa's 1778 ''Pectunculus striatulus'' was a different northern species or not. Linnaeus afterwards mentioned that his ''V. gallina'' also occurs in '. In 1952, following Dodge, the name ''Chamelea gallina'' was considered to be valid. There were for a while two recognised subspecies: the Mediterranean'' C. g. gallina'', and the Atlantic ''C. g. striatula''. However by 2016, the two subspecies were elevated to the species level, and listed separately on the database WoRMS. Characteristics The shell is solid and thick, with two equal sized valves and up to five centimetres long. It is broadly triangular but asymmetrical, having a round anterior margin but a somewhat elongated posterior. The periostracum is thin and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ensis Ensis
''Ensis ensis'', or the sword razor, is a razor clam, a marine bivalve mollusc in the family Pharidae. It lives buried in the sand and is found off the coasts of northwest Europe. Description The two valves that make up the shell of ''Ensis ensis'' are parallel-sided, narrow and curved. The adult shell can be up to ten centimetres in length. The valves are thin and rather brittle. The edges are parallel, tapering slightly towards the posterior and are off white with transverse bands of brown. The shell is sculpted with fine co-marginal lines and the annual growth lines can be seen. The inner side of the shell is white with a purplish sheen. The periostracum is olive green and the foot is reddish. Two identifying features are that the posterior adductor muscle is positioned some one and a half times its own length from the pallial sinus, and that the muscle that retracts the foot is posterior to the insertion point of the ligature. ''Ensis siliqua'' and '' Ensis arcuatus'' are two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tellina Fabula
''Fabulina fabula'', the bean-like tellin, is a species of marine bivalve mollusc in the family Tellinidae. It is found off the coasts of northwest Europe, where it lives buried in sandy sediments. Bivalves are molluscs with a body compressed between two usually similar shell valves joined by an elastic ligament. There are teeth at the edge of the shell and the animal has a muscular foot, gills, siphons, mouth and gut and is surrounded by a mantle inside the shell. Description The shell of ''Fabulina fabula'' is brittle and flattened and grows to a length of twenty millimeters. The outline is oval but the shell is asymmetric with the hinge slightly off centre and the beaks slightly behind the midline. The anterior dorsal margin curves gently and the anterior margin is rounded. The posterior dorsal margin is straighter and the posterior margin is somewhat pointed. The periostracum is transparent and glossy and the shell is white with tinges of yellow or brown. There is a scu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusca
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estimated between 60,000 and 100,000 additional species. The proportion of undescribed species is very high. Many taxa remain poorly studied. Molluscs are the largest marine phylum, comprising about 23% of all the named marine organisms. Numerous molluscs also live in freshwater and terrestrial habitats. They are highly diverse, not just in size and anatomical structure, but also in behaviour and habitat. The phylum is typically divided into 7 or 8 taxonomic classes, of which two are entirely extinct. Cephalopod molluscs, such as squid, cuttlefish, and octopuses, are among the most neurologically advanced of all invertebrates—and either the giant squid or the colossal squid is the largest known invertebrate species. The gastropod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bivalvia
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estim ... that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bivalves have no head and they lack some usual molluscan organs, like the radula and the odontophore. They include the clams, oysters, Cockle (bivalve), cockles, mussels, scallops, and numerous other family (biology), families that live in saltwater, as well as a number of families that live in freshwater. The majority are filter feeders. The gills have evolved into Ctenidium (mollusc), ctenidia, specialised organs for feeding and breathing. Most bivalves bury themselves in sediment, where they a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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