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Cirrus (biology)
In biology, a cirrus , plural ''cirri'', , (from the Latin ''cirrus'' meaning a ''curl-like tuft or fringe'') is a long, thin structure in an animal similar to a tentacle but generally lacking the tentacle's strength, flexibility, thickness, and sensitivity. In the sheep liver fluke, for example, the ''cirrus'' is the worm's muscular penis and when not in use is retained within a ''cirrus sac'' or ''pouch'' near the animal's head. The same structure exists in the various ''Taenia'' species of tapeworm. In the clam worms, however, the cirrus is the tentacular process or growth on each of the feet (''parpodia''), either the ''dorsal cirrus'' or the ''ventral cirrus'', and has nothing to do with reproduction. Among the bristleworms, a cirrus is a tentacular growth near the head or notopodium containing sense organs and may be either dorsal, ventral, or lamellar. Among the ribbonworms, the ''caudal cirrus'' is a small thread-like growth at the posterior end of the worm. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acanthemblemaria Aspera, Adult Female (Roughhead Blenny)
''Acanthemblemaria'' is a genus of chaenopsid blennies native to the Atlantic and Pacific Oceans. Etymology AcanthemblemariaGreek language, : Greek, akantha = thorn + Greek language, Greek, emblema, -atos, anything that is nailed, knocked in; also anything with bass or high relief Description Body elongated; head short and blunt; pointed or blunt spines on snout, below eye, sometimes on top of head; 2 rows of very well developed teeth on the roof of the mouth; 1 pair of Branch (other), branched or unbranchecirriover eyescirriover Nostril, nostrils; usually with a notch between the spiny and soft parts of the dorsal fin Species The 21 recognized species in this genus are: * ''Acanthemblemaria aspera'' (William Harding Longley, Longley, 1927) (roughhead blenny) * ''Acanthemblemaria atrata'' Philip A. Hastings, Hastings & David Ross Robertson, D. R. Robertson, 1999 (Cocos barnacle blenny) * ''Acanthemblemaria balanorum'' Vernon E. Brock, Brock, 1940 (clubhead blenny) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tentacle
In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work mainly like muscular hydrostats. Most forms of tentacles are used for grasping and feeding. Many are sensory organs, variously receptive to touch, vision, or to the smell or taste of particular foods or threats. Examples of such tentacles are the eyestalks of various kinds of snails. Some kinds of tentacles have both sensory and manipulatory functions. A tentacle is similar to a cirrus, but a cirrus is an organ that usually lacks the tentacle's strength, size, flexibility, or sensitivity. A nautilus has cirri, but a squid has tentacles. Invertebrates Molluscs Many molluscs have tentacles of one form or another. The most familiar are those of the pulmonate land snails, which usually have two sets of tentacles on the head: when extended ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sheep Liver Fluke
''Fasciola hepatica'', also known as the common liver fluke or sheep liver fluke, is a parasitic trematode (fluke or flatworm, a type of helminth) of the class Trematoda, phylum Platyhelminthes. It infects the livers of various mammals, including humans, and is transmitted by sheep and cattle to humans the world over. The disease caused by the fluke is called fasciolosis or fascioliasis, which is a type of helminthiasis and has been classified as a neglected tropical disease. Fasciolosis is currently classified as a plant/food-borne trematode infection, often acquired through eating the parasite's metacercariae encysted on plants. ''F. hepatica'', which is distributed worldwide, has been known as an important parasite of sheep and cattle for decades and causes significant economic losses in these livestock species, up to £23 million in the UK alone. Because of its relatively large size and economic importance, it has been the subject of many scientific investigations and may be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Penis
A penis (plural ''penises'' or ''penes'' () is the primary sexual organ that male animals use to inseminate females (or hermaphrodites) during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males do not bear a penis in every animal species, and in those species in which the male does bear a so-called penis, the penises in the various species are not necessarily homologous. The term ''penis'' applies to many intromittent organs, but not to all. As an example, the intromittent organ of most cephalopoda is the hectocotylus, a specialized arm, and male spiders use their pedipalps. Even within the Vertebrata there are morphological variants with specific terminology, such as Hemipenis, hemipenes. In most species of animals in which there is an organ that might reasonably be described as a penis, it has no major function other than intromission, or at least conveying the sperm to the female, but in the Eutheria, placental mammals the peni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taenia (genus)
''Taenia'' is the type genus of the Taeniidae family of tapeworms (a type of helminth). It includes some important parasites of livestock. Members of the genus are responsible for taeniasis and cysticercosis in humans, which are types of helminthiasis belonging to the group of neglected tropical diseases. More than 100 species are recorded. They are morphologically characterized by a ribbon-like body composed of a series of segments called proglottids; hence the name ''Taenia'' (Greek ταίνια, ''tainia'' meaning ribbon, bandage, or stripe). The anterior end of the body is the scolex. Some members of the genus ''Taenia'' have an armed scolex (hooks and/or spines located in the "head" region); of the two major human parasites, ''Taenia saginata'' has an unarmed scolex, while ''Taenia solium'' has an armed scolex. The proglottids have a central ovary, with a vitellarium (yolk gland) posterior to it. As in all cyclophyllid cestodes, a genital pore occurs on the side of the pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nereidae
Nereididae (formerly spelled Nereidae) are a family of polychaete worms. It contains about 500 – mostly marine – species grouped into 42 genera. They may be commonly called ragworms or clam worms. Characteristics The prostomium of Nereididae bears a pair of palps that are differentiated into two units, the proximal unit is much larger than the distal unit. Parapodia are mostly biramous (only the first two pairs are uniramous). Peristomium fused with the first body segment, with usually two pairs of tentacular cirri. The first body segment with 1-2 pairs tentacular cirri without aciculae. Compound setae present. Notopodia are distinct (rarely reduced), usually with more flattened lobes, notosetae compound falcigers and/or spinigers (rarely notosetae absent). They have two prostomial antennae (absent in ''Micronereis''). Their pharynx, when everted, clearly consists of two portions, with a pair of strong jaws on the distal portion and usually with conical teeth on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polychaete
Polychaeta () is a paraphyletic class (biology), class of generally marine invertebrate, marine annelid worms, common name, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. More than 10,000 species are described in this class. Common representatives include the lugworm (''Arenicola marina'') and the Alitta virens, sandworm or Alitta succinea, clam worm ''Alitta''. Polychaetes as a class are robust and widespread, with species that live in the coldest ocean temperatures of the abyssal plain, to forms which tolerate the extremely high temperatures near hydrothermal vents. Polychaetes occur throughout the Earth's oceans at all depths, from forms that live as plankton near the surface, to a 2- to 3-cm specimen (still unclassified) observed by the robot ocean probe Nereus (underwater vehicle), ''Nereus'' at the bottom of the Challenger Deep, the deepes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Notopodium
In invertebrates, the term parapodium ( Gr. ''para'', beyond or beside + ''podia'', feet; plural: parapodia) refers to lateral outgrowths or protrusions from the body. Parapodia are predominantly found in annelids, where they are paired, unjointed lateral outgrowths that bear the chaetae. In several groups of sea snails and sea slugs, 'parapodium' refers to lateral fleshy protrusions. __TOC__ Annelid parapodia Most species of polychaete annelids have paired, fleshy parapodia which are segmentally arranged along the body axis. Parapodia vary greatly in size and form, reflecting a variety of functions, such as gas exchange, anchorage, protection and locomotion. General description Parapodia in polychaetes can be uniramous (consisting of one lobe or ramus) but are usually biramous (two lobes or rami). In the latter case, the dorsal lobes are called notopodia and the ventral lobes neuropodia. Both neuropodia and notopodia may possess a bundle of chaetae (neurochaetae and notochaet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heteronemertea
Heteronemertea is a monophyletic order of about 500 species of nemertean worm. It contains genera such as ''Lineus'' and ''Cerebratulus'', and includes the largest and most muscular nemerteans. Almost all heteronemerteans have three primary body-wall muscle strata: an outer longitudinal, a middle circular, and an inner longitudinal. The lateral nerve cords are outside the circular muscle, as in palaeonemerteans, but separated from the epidermis by the usually well-developed outer longitudinal muscle. Taxonomy Families within the order Heteronemertea include: * Baseodiscidae * Cerebratulidae * Gorgonorhynchidae *Lineidae Lineidae is a family of nemertean worms. It contains the following genera: * '' Aetheolineus'' Senz, 1993 * '' Ammolineus'' Senz, 2001 * ''Antarctolineus'' Muller & Scripcariu, 1964 * ''Apatronemertes'' Wilfert & Gibson, 1974 * '' Australineus'' ... * Mixolineidae * Panorhynchidae * Poliopsiidae * Polybrachiorhynchidae * Pussylineidae * Riseriellidae * Vale ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feather Star
Crinoids are marine animals that make up the class Crinoidea. Crinoids that are attached to the sea bottom by a stalk in their adult form are commonly called sea lilies, while the unstalked forms are called feather stars or comatulids, which are members of the largest crinoid order, Comatulida. Crinoids are echinoderms in the phylum Echinodermata, which also includes the starfish, brittle stars, sea urchins and sea cucumbers. They live in both shallow water and in depths as great as . Adult crinoids are characterised by having the mouth located on the upper surface. This is surrounded by feeding arms, and is linked to a U-shaped gut, with the anus being located on the oral disc near the mouth. Although the basic echinoderm pattern of fivefold symmetry can be recognised, in most crinoids the five arms are subdivided into ten or more. These have feathery pinnules and are spread wide to gather planktonic particles from the water. At some stage in their lives, most crinoids have a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barnacle
A barnacle is a type of arthropod constituting the subclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in erosive settings. They are sessile (nonmobile) and most are suspension feeders, but those in infraclass Rhizocephala are highly specialized parasites on crustaceans. They have four nektonic (active swimming) larval stages. Around 1,000 barnacle species are currently known. The name is Latin, meaning "curl-footed". The study of barnacles is called cirripedology. Description Barnacles are encrusters, attaching themselves temporarily to a hard substrate or a symbiont such as a whale ( whale barnacles), a sea snake ('' Platylepas ophiophila''), or another crustacean, like a crab or a lobster (Rhizocephala). The most common among them, "acorn barnacles" ( Sessilia), are sessile where they grow their shells directly onto the substrate. Peduncul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crinoid
Crinoids are marine animals that make up the class Crinoidea. Crinoids that are attached to the sea bottom by a stalk in their adult form are commonly called sea lilies, while the unstalked forms are called feather stars or comatulids, which are members of the largest crinoid order, Comatulida. Crinoids are echinoderms in the phylum Echinodermata, which also includes the starfish, brittle stars, sea urchins and sea cucumbers. They live in both shallow water and in depths as great as . Adult crinoids are characterised by having the mouth located on the upper surface. This is surrounded by feeding arms, and is linked to a U-shaped gut, with the anus being located on the oral disc near the mouth. Although the basic echinoderm pattern of fivefold symmetry can be recognised, in most crinoids the five arms are subdivided into ten or more. These have feathery pinnules and are spread wide to gather planktonic particles from the water. At some stage in their lives, most crinoids have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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