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Myzostomida
The Myzostomida or Myzostomatida are an order of small marine worms, which are parasitic on echinoderms, mostly crinoids. These highly unusual and diverse annelids were first discovered by Friedrich Sigismund Leuckart in 1827. Morphology A typical myzostomid has a flattened, rounded shape, with a thin edge drawn out into delicate radiating hairs called cirri. The dorsal surface is smooth, with five pairs of parapodia on the bottom surface. These parapodia are armed with supporting and hooked setae, by means of which the worm adheres to its host. Beyond the parapodia are four pairs of organs, often called suckers. These organs are probably of sensory nature, and are comparable to the lateral sense organs of capitellids. The mouth and cloacal opening are generally at opposite ends of the bottom surface. The former leads to a protrusible pharynx, from which the esophagus opens into a wide intestinal chamber with branching lateral diverticula. There appears to be no vascular sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annelids
The annelids (Annelida , from Latin ', "little ring"), also known as the segmented worms, are a large phylum, with over 22,000 extant species including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecologies – some in marine environments as distinct as tidal zones and hydrothermal vents, others in fresh water, and yet others in moist terrestrial environments. The Annelids are bilaterally symmetrical, triploblastic, coelomate, invertebrate organisms. They also have parapodia for locomotion. Most textbooks still use the traditional division into polychaetes (almost all marine), oligochaetes (which include earthworms) and leech-like species. Cladistic research since 1997 has radically changed this scheme, viewing leeches as a sub-group of oligochaetes and oligochaetes as a sub-group of polychaetes. In addition, the Pogonophora, Echiura and Sipuncula, previously regarded as separate phyla, are now regarded as sub-groups of po ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myzostoma Fuscomaculatum
''Myzostoma fuscomaculatum'', the crinoid worm, is a species of marine (ocean), marine worm in the family (biology), family Myzostomida.Lanterbecq D., Hempson T., Griffiths C. & Eeckhaut I, 2008. ''Myzostoma fuscomaculatum'' (Myzostomida), a new myzostome species from False Bay, South Africa. ''Hydrobiologia'' Description Crinoid worms are tiny worms with stubby legs which live on the elegant feather star, ''Tropiometra carinata''. They are usually well camouflaged to match their host. They grow to 2mm in total length.Branch, G.M., Branch, M.L, Griffiths, C.L. and Beckley, L.E. 2010. ''Two Oceans: a guide to the marine life of southern Africa'' Distribution Crinoid worms are found off the South African coast in False Bay in 10m to at least 35m of water. They appear to be endemism, endemic. Ecology These animals are parasitism, parasitic on their host crinoid and eat scraps of its food and any waste products. References {{Taxonbar, from=Q16981141 Polychaetes Animal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Myzostoma Pulvinar
''Myzostoma'' is a genus of marine worms, which are parasitic on crinoids in the family Myzostomidae. Species The following species are classified in this genus: *''Myzostoma abundans'' Graff, 1883 *''Myzostoma adhaerens'' Remscheid, 1918 *''Myzostoma agassizii'' Graff, 1883 *''Myzostoma alatum'' Graff, 1884 *''Myzostoma ambiguum'' Graff, 1887 *''Myzostoma antarcticum'' Stummer-Traunfels, 1908 *''Myzostoma antennatum'' Graff, 1884 *'' Myzostoma areolatum'' Graff, 1883 *''Myzostoma armatae'' Grygier, 1989 *'' Myzostoma aruense'' Remscheid, 1918 *''Myzostoma asteriae'' Marenzeller, 1895 *'' Myzostoma asymmetricum'' Graff, 1884 *'' Myzostoma atrum'' Atkins, 1927 *'' Myzostoma attenuatum'' Grygier, 1989 *'' Myzostoma australe'' Rouse, 2003 *'' Myzostoma beardi'' Graff, 1887 *'' Myzostoma belli'' Wheeler, 1897 *'' Myzostoma bicaudatum'' Greeff, 1883 *'' Myzostoma bicorne'' Remscheid, 1918 *'' Myzostoma bocki'' Jägersten, 1937 *'' Myzostoma brachiatum'' Graff, 1877 *''Myzostoma brevic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coelom
The coelom (or celom) is the main body cavity in most animals and is positioned inside the body to surround and contain the digestive tract and other organs. In some animals, it is lined with mesothelium. In other animals, such as molluscs, it remains undifferentiated. In the past, and for practical purposes, coelom characteristics have been used to classify bilaterian animal phyla into informal groups. Etymology The term ''coelom'' derives from the Ancient Greek word (), meaning 'cavity'. Structure Development The coelom is the mesodermally lined cavity between the gut and the outer body wall. During the development of the embryo, coelom formation begins in the gastrulation stage. The developing digestive tube of an embryo forms as a blind pouch called the archenteron. In Protostomes, the coelom forms by a process known as schizocoely. The archenteron initially forms, and the mesoderm splits into two layers: the first attaches to the body wall or ectoderm, fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fridtjof Nansen
Fridtjof Wedel-Jarlsberg Nansen (; 10 October 186113 May 1930) was a Norwegian polymath and Nobel Peace Prize laureate. He gained prominence at various points in his life as an explorer, scientist, diplomat, and humanitarian. He led the team that made the first crossing of the Greenland interior in 1888, traversing the island on cross-country skis. He won international fame after reaching a record northern latitude of 86°14′ during his ''Fram'' expedition of 1893–1896. Although he retired from exploration after his return to Norway, his techniques of polar travel and his innovations in equipment and clothing influenced a generation of subsequent Arctic and Antarctic expeditions. Nansen studied zoology at the Royal Frederick University in Christiania and later worked as a curator at the University Museum of Bergen where his research on the central nervous system of lower marine creatures earned him a doctorate and helped establish neuron doctrine. Later, neuroscientist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antedon
''Antedon'' is a genus of free-swimming, stemless crinoids. The genus first appeared in the fossil record in the Cretaceous period. Characteristics Members of this genus have no stems but have five pairs of feathery arms arising from a central concave disc. There are a number of cirri or unbranched appendages on a low, cone-shaped dorsal ossicle, a bone-like structure in the centre of the disc. The mouth and the ambulacral grooves are also on the upper surface. Clawed cirri on the lower surface provide temporary attachment to the substrate. There is great variability in the morphological features in Antedonids found in different habitats and the main distinguishing feature among the species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ... is the number of cirri. Species The f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gut (anatomy)
The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and other animals, including the esophagus, stomach, and intestines. Food taken in through the mouth is digested to extract nutrients and absorb energy, and the waste expelled at the anus as feces. ''Gastrointestinal'' is an adjective meaning of or pertaining to the stomach and intestines. Most animals have a "through-gut" or complete digestive tract. Exceptions are more primitive ones: sponges have small pores (ostia) throughout their body for digestion and a larger dorsal pore ( osculum) for excretion, comb jellies have both a ventral mouth and dorsal anal pores, while cnidarians and acoels have a single pore for both digestion and excretion. The human gastrointestinal tract consists of the esophagus, stomach, and intestines, and is div ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pinnule
A leaflet (occasionally called foliole) in botany is a leaf-like part of a compound leaf. Though it resembles an entire leaf, a leaflet is not borne on a main plant stem or branch, as a leaf is, but rather on a petiole or a branch of the leaf. Compound leaves are common in many plant families and they differ widely in morphology. The two main classes of compound leaf morphology are palmate and pinnate. For example, a '' hemp'' plant has palmate compound leaves, whereas some species of ''Acacia'' have pinnate leaves. The ultimate free division (or leaflet) of a compound leaf, or a pinnate subdivision of a multipinnate leaf is called a pinnule or pinnula. Image:Ветвь акации.jpg, Pinnate leaf of a legume with 10 leaflets Image:Mimosa Pudica.gif, '' Mimosa pudica'' folding leaflets inward. See also * Compound leaf A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for phot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
