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Cladonematidae
Cladonematidae is a small family of anthomedusan hydrozoans. They have stolonal hydroid colonies, and their medusae are benthic and can crawl across the sediment; in many species they have lost the ability to swim however.Schuchert 009/ref> Several members of this lineage were formerly considered a separate family Eleutheriidae.WoRMS Description The hydranths have a circular mouth surrounded by a single whorl of adhesive tentacles which each bear a little knob at the tip; in some Cladonematidae an aboral whorl of thread-like unknobbed tentacles is also present. They have a preoral chamber formed by epidermal gland cells. The medusae bud off at the base of the hydrants, though where aboral tentacle are present these are located between the stolons and the budding sites. Cladonematidae medusae have a various extend of nematocysts around their umbrellar margin, varying between a continuous dense ring to none at all among the species. The number of radial canals and whether they ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Staurocladia
''Staurocladia'' is a genus of anthomedusan hydrozoans. Its former family Eleutheriidae is now included in the Cladonematidae. Species In biology, a species is the basic unit of 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 the appropriate s ... include: *'' Staurocladia acuminata'' *'' Staurocladia alternata'' *'' Staurocladia bilateralis'' *'' Staurocladia charcoti'' *'' Staurocladia haswelli'' *'' Staurocladia oahuensis'' *'' Staurocladia portmanni'' *'' Staurocladia schizogena'' *'' Staurocladia ulvae'' *'' Staurocladia vallentini'' *'' Staurocladia wellingtoni'' References Cladonematidae Hydrozoan genera {{anthoathecata-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eleutheria (hydrozoan)
''Eleutheria'' is a genus of hydrozoans belonging to the family Cladonematidae Cladonematidae is a small family of anthomedusan hydrozoans. They have stolonal hydroid colonies, and their medusae are benthic and can crawl across the sediment; in many species they have lost the ability to swim however.Schuchert 009/ref> Se .... The species of this genus are found in Europe and Australia. Species: *'' Eleutheria claparedii'' *'' Eleutheria dichotoma'' *'' Eleutheria heptonema'' References Cladonematidae Hydrozoan genera {{anthoathecata-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladonema (hydrozoan)
''Cladonema'' is a genus of hydrozoa belonging to the family Cladonematidae. The genus has almost cosmopolitan distribution In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of the world in appropriate habitats. Such a taxon, usually a species, is said to exhibit cosmopolitanism or cosmopolitism. The ext .... Species: *'' Cladonema californicum'' *'' Cladonema myersi'' *'' Cladonema novaezelandiae'' *'' Cladonema pacificum'' *'' Cladonema radiatum'' *'' Cladonema timmsii'' References Cladonematidae Hydrozoan genera {{anthoathecata-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anthomedusae
Anthoathecata, or the athecate hydroids, are an order of hydrozoans belonging to the phylum Cnidaria. A profusion of alternate scientific names exists for this long-known, heavily discussed, and spectacular group. It has also been called Gymnoblastea and (with or without an emended ending ''-ae''), Anthomedusa, Athecata, Hydromedusa, and Stylasterina. There are about 1,200 species worldwide.Schuchert, P. (2014). Anthoathecata. Accessed through: Schuchert, P. (2014) World Hydrozoa database at http://www.marinespecies.org/hydrozoa/aphia.php?p=taxdetails&id=13551 on 2014-10-31 These hydrozoans always have a polyp stage. Their hydranths grow either solitary or in colonies. There is no firm perisarc around the polyp body. The medusae, or jellyfish, are solitary animals, with tentacles arising from the bell margin, lacking statocysts but possessing radial canals. Their gonads are on the manubrium ("handle").Bouillon, J.; Gravili, C.; Pagès, F.; Gili, J.-M.; Boero, F. (2006). An intro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lapsus
In philology, a lapsus (Latin for "lapse, slip, error") is an involuntary mistake made while writing or speaking. Investigations In 1895 an investigation into verbal slips was undertaken by a philologist and a psychologist, Rudolf Meringer and Karl Mayer, who collected many examples and divided them into separate types. Psychoanalysis Freud was to become interested in such mistakes from 1897 onwards, developing an interpretation of slips in terms of their unconscious meaning. Subsequently followers of his like Ernest Jones developed the theme of lapsus in connection with writing, typing, and misprints. According to Freud's early psychoanalytic theory, a lapsus represents a bungled act that hides an unconscious desire: “the phenomena can be traced back to incompletely suppressed psychical material...pushed away by consciousness”. Jacques Lacan would thoroughly endorse the Freudian interpretation of unconscious motivation in the slip, arguing that “in the ''lapsus'' it i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nematocyst
A cnidocyte (also known as a cnidoblast or nematocyte) is an explosive cell containing one large secretory organelle called a cnidocyst (also known as a cnida () or nematocyst) that can deliver a sting to other organisms. The presence of this cell defines the phylum Cnidaria (corals, sea anemones, hydrae, jellyfish, etc.). Cnidae are used to capture prey and as a defense against predators. A cnidocyte fires a structure that contains a toxin within the cnidocyst; this is responsible for the stings delivered by a cnidarian. Structure and function Each cnidocyte contains an organelle called a cnida, cnidocyst, nematocyst, ptychocyst or spirocyst. This organelle consists of a bulb-shaped capsule containing a coiled hollow tubule structure attached to it. An immature cnidocyte is referred to as a cnidoblast or nematoblast. The externally oriented side of the cell has a hair-like trigger called a cnidocil, which is a mechano- and chemo-receptor. When the trigger is activated, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus comes above species and below family (taxonomy), family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. ''Panthera leo'' (lion) and ''Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomy (biology), taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ocelli
A simple eye (sometimes called a pigment pit) refers to a form of eye or an optical arrangement composed of a single lens and without an elaborate retina such as occurs in most vertebrates. In this sense "simple eye" is distinct from a multi-lensed "compound eye", and is not necessarily at all simple in the usual sense of the word. The structure of an animal's eye is determined by the environment in which it lives, and the behavioural tasks it must fulfill to survive. Arthropods differ widely in the habitats in which they live, as well as their visual requirements for finding food or conspecifics, and avoiding predators. Consequently, an enormous variety of eye types are found in arthropods. They possess a wide variety of novel solutions to overcome visual problems or limitations. Use of the term ''simple eye'' is flexible, and must be interpreted in proper context; for example, the eyes of humans and of other large animals such as most cephalopods, are ''camera eyes'' and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abaxial
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Gonad
A gonad, sex gland, or reproductive gland is a mixed gland that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, produces sperm in the form of spermatozoa. The female gonad, the ovary, produces egg cells. Both of these gametes are haploid cells. Some hermaphroditic animals have a type of gonad called an ovotestis. Evolution It is hard to find a common origin for gonads, but gonads most likely evolved independently several times. Regulation The gonads are controlled by luteinizing hormone and follicle-stimulating hormone, produced and secreted by gonadotropes or gonadotrophins in the anterior pituitary gland. This secretion is regulated by gonadotropin-releasing hormone produced in the hypothalamus. Development Gonads start developing as a common primordium (an organ in the earliest stage of development), in the form of genital ridges, which are only l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pouch (marsupial)
The pouch is a distinguishing feature of female marsupials, monotremes and possibly most extinct non-placental mammals including eutherians like ''Zalambdalestes'' (and rarely in the males as in the water opossumNogueira, José Carlos, et al.Morphology of the male genital system of Chironectes minimus and comparison to other didelphid marsupials. Journal of mammalogy 85.5 (2004): 834-841. and the extinct thylacine); the name marsupial is derived from the Latin ''marsupium'', meaning "pouch". Marsupials give birth to a live but relatively undeveloped fetus called a joey. When the joey is born it crawls from inside the mother to the pouch. The pouch is a fold of skin with a single opening that covers the teats. Inside the pouch, the blind offspring attaches itself to one of the mother’s teats and remains attached for as long as it takes to grow and develop to a juvenile stage. Variations Pouches are different amongst different marsupials, two kinds distinguishable (on the front ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorsum (biology)
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek language, Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and anatomical axis, anatomical axes. The meaning of terms that are used can change depending on whether an organism is bipedal or quadrupedal. Additionally, for some animals such as invertebrates, some terms may not have any meaning at all; for example, an animal that is radially symmetrical will have no anterior surface, but can still have a description that a part is close to the middle ("proximal") or further from the middle ("distal"). International organisations have determined vocabularies that are often used as standard vocabular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
