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Atorella Japonica
''Atorella'' is a genus of crown jellyfish. It is the only genus in the monotypic family Atorellidae and includes five species. Members of this family are known from the eastern coast of Africa and the western coast of Panama. Characteristics Members of this genus are characterised by having exactly six tentacles and six rhopalia, twelve marginal lappets and twelve pedalia. The bell ranges from in diameter. The bell is colourless and transparent and the four orange gonads can be seen inside. The mouth has four lips. Species The World Register of Marine Species lists the following species:- *''Atorella arcturi'' Bigelow, 1928 *'' Atorella japonica'' Kawaguti & Matsuno, 1981 *''Atorella octogonus'' Mills, Larson & Young, 1987 *''Atorella subglobosa'' Vanhöffen, 1902 *''Atorella vanhoeffeni ''Atorella'' is a genus of crown jellyfish. It is the only genus in the monotypic family Atorellidae and includes five species. Members of this family are known from the eastern coast of Af ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atorella Vanhoffeni
''Atorella'' is a genus of crown jellyfish. It is the only genus in the monotypic family Atorellidae and includes five species. Members of this family are known from the eastern coast of Africa and the western coast of Panama. Characteristics Members of this genus are characterised by having exactly six tentacles and six rhopalia, twelve marginal lappets and twelve pedalia. The bell ranges from in diameter. The bell is colourless and transparent and the four orange gonads can be seen inside. The mouth has four lips. Species The World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialist ... lists the following species:- *'' Atorella arcturi'' Bigelow, 1928 *'' Atorella japonica'' Kawaguti & Matsuno, 1981 *'' Atorella octogonus'' Mills, Larson & Young, 1987 *' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gonads
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 late ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atorella Vanhoeffeni
''Atorella'' is a genus of crown jellyfish. It is the only genus in the monotypic family Atorellidae and includes five species. Members of this family are known from the eastern coast of Africa and the western coast of Panama. Characteristics Members of this genus are characterised by having exactly six tentacles and six rhopalia, twelve marginal lappets and twelve pedalia. The bell ranges from in diameter. The bell is colourless and transparent and the four orange gonads can be seen inside. The mouth has four lips. Species The World Register of Marine Species lists the following species:- *''Atorella arcturi ''Atorella'' is a genus of crown jellyfish. It is the only genus in the monotypic family Atorellidae and includes five species. Members of this family are known from the eastern coast of Africa and the western coast of Panama. Characteristics Me ...'' Bigelow, 1928 *'' Atorella japonica'' Kawaguti & Matsuno, 1981 *'' Atorella octogonus'' Mills, Larson & Young, 1987 *'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atorella Subglobosa
''Atorella'' is a genus of crown jellyfish. It is the only genus in the monotypic family Atorellidae and includes five species. Members of this family are known from the eastern coast of Africa and the western coast of Panama. Characteristics Members of this genus are characterised by having exactly six tentacles and six rhopalia, twelve marginal lappets and twelve pedalia. The bell ranges from in diameter. The bell is colourless and transparent and the four orange gonads can be seen inside. The mouth has four lips. Species The World Register of Marine Species lists the following species:- *''Atorella arcturi'' Bigelow, 1928 *'' Atorella japonica'' Kawaguti & Matsuno, 1981 *'' Atorella octogonus'' Mills, Larson & Young, 1987 *'' Atorella subglobosa'' Vanhöffen, 1902 *''Atorella vanhoeffeni ''Atorella'' is a genus of crown jellyfish. It is the only genus in the monotypic family Atorellidae and includes five species. Members of this family are known from the eastern coast of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atorella Octogonus
''Atorella'' is a genus of crown jellyfish. It is the only genus in the monotypic family Atorellidae and includes five species. Members of this family are known from the eastern coast of Africa and the western coast of Panama. Characteristics Members of this genus are characterised by having exactly six tentacles and six rhopalia, twelve marginal lappets and twelve pedalia. The bell ranges from in diameter. The bell is colourless and transparent and the four orange gonads can be seen inside. The mouth has four lips. Species The World Register of Marine Species lists the following species:- *''Atorella arcturi'' Bigelow, 1928 *'' Atorella japonica'' Kawaguti & Matsuno, 1981 *'' Atorella octogonus'' Mills, Larson & Young, 1987 *''Atorella subglobosa'' Vanhöffen, 1902 *''Atorella vanhoeffeni ''Atorella'' is a genus of crown jellyfish. It is the only genus in the monotypic family Atorellidae and includes five species. Members of this family are known from the eastern coast of A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atorella Japonica
''Atorella'' is a genus of crown jellyfish. It is the only genus in the monotypic family Atorellidae and includes five species. Members of this family are known from the eastern coast of Africa and the western coast of Panama. Characteristics Members of this genus are characterised by having exactly six tentacles and six rhopalia, twelve marginal lappets and twelve pedalia. The bell ranges from in diameter. The bell is colourless and transparent and the four orange gonads can be seen inside. The mouth has four lips. Species The World Register of Marine Species lists the following species:- *''Atorella arcturi'' Bigelow, 1928 *'' Atorella japonica'' Kawaguti & Matsuno, 1981 *''Atorella octogonus'' Mills, Larson & Young, 1987 *''Atorella subglobosa'' Vanhöffen, 1902 *''Atorella vanhoeffeni ''Atorella'' is a genus of crown jellyfish. It is the only genus in the monotypic family Atorellidae and includes five species. Members of this family are known from the eastern coast of Af ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atorella Arcturi
''Atorella'' is a genus of crown jellyfish. It is the only genus in the monotypic family Atorellidae and includes five species. Members of this family are known from the eastern coast of Africa and the western coast of Panama. Characteristics Members of this genus are characterised by having exactly six tentacles and six rhopalia, twelve marginal lappets and twelve pedalia. The bell ranges from in diameter. The bell is colourless and transparent and the four orange gonads can be seen inside. The mouth has four lips. Species The World Register of Marine Species The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialist ... lists the following species:- *'' Atorella arcturi'' Bigelow, 1928 *'' Atorella japonica'' Kawaguti & Matsuno, 1981 *'' Atorella octogonus'' Mills, Larson & Young, 1987 *' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World Register Of Marine Species
The World Register of Marine Species (WoRMS) is a taxonomic database that aims to provide an authoritative and comprehensive list of names of marine organisms. Content The content of the registry is edited and maintained by scientific specialists on each group of organism. These taxonomists control the quality of the information, which is gathered from the primary scientific literature as well as from some external regional and taxon-specific databases. WoRMS maintains valid names of all marine organisms, but also provides information on synonyms and invalid names. It is an ongoing task to maintain the registry, since new species are constantly being discovered and described by scientists; in addition, the nomenclature and taxonomy of existing species is often corrected or changed as new research is constantly being published. Subsets of WoRMS content are made available, and can have separate badging and their own home/launch pages, as "subregisters", such as the ''World List of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhopalia
Rhopalia (singular: rhopalium) are small sensory structures of certain Scyphozoan (true jellyfish) and Cubozoan (box jellyfish) species. Description The structures typically occur in multiples of four, are bell shaped and face outward from invaginations around the bell of the jelly's mantle. They are each connected ectodermally to the periphery of other rhopalia by a stalk-like projections which join extremities in a skirt-like shape. These connections form the junctions of the cnidarian 'central nervous system', which synapse within the rhopalial centers. Rhopalia vary in form, size and number, but ubiquitously consist of specialized structures to sense light (ocelli), which line the structure, and regions to perceive gravity ( statoliths) at their terminal tip. Rhopalia are unique to the medusoid forms of Cnidarians and are best studied in Scyphozoa'','' within the genus ''Aurelia,'' which exhibits the most typical arrangement and structure of rhopalia in marginal indentations a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ernst Vanhöffen
Ernst Vanhöffen (15 November 1858, in Wehlau – 14 June 1918) was a German zoologist. He studied geology, botany and zoology at the universities of Berlin and Königsberg, graduating in 1888 with the thesis ''Untersuchungen über semaeostome und rhizostome Medusen''. In 1889–90 he conducted research of jellyfish at the Stazione Zoologica Anton Dohrn in Naples. In 1892–93 he participated in a ''Gesellschaft für Erdkunde zu Berlin''-sponsored expedition to West Greenland under the leadership of Erich von Drygalski (1865–1949). Afterwards, he worked for a few years at the Institute of Zoology in Kiel. In 1898–99 he took part in the ''Deutschen Tiefsee-Expedition'' aboard the steamship "Valdivia". From an abundant yield of deep-sea marine fauna collected on the expedition, Vanhöffen was tasked with processing medusa species. After his return to Germany, he served as a lecturer at the University of Kiel, attaining the title of professor in March 1901. From August 1901 t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tentacles
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] |
Panama
Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Costa Rica to the west, Colombia to the southeast, the Caribbean Sea to the north, and the Pacific Ocean to the south. Its capital and largest city is Panama City, whose metropolitan area is home to nearly half the country's million people. Panama was inhabited by indigenous tribes before Spanish colonists arrived in the 16th century. It broke away from Spain in 1821 and joined the Republic of Gran Colombia, a union of Nueva Granada, Ecuador, and Venezuela. After Gran Colombia dissolved in 1831, Panama and Nueva Granada eventually became the Republic of Colombia. With the backing of the United States, Panama seceded from Colombia in 1903, allowing the construction of the Panama Canal to be completed by the United States Army Corps of En ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
