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Sagitta (arrowworm)
''Sagitta'' is a genus of Chaetognatha The Chaetognatha or chaetognaths (meaning ''bristle-jaws'') are a phylum of predatory marine worms that are a major component of plankton worldwide. Commonly known as arrow worms, about 20% of the known Chaetognatha species are benthic, and can ..., a phylum commonly known as arrowworms or arrow worms. Phylum Chaetognatha comprises small marine worms. This genus is characterized in part by the distribution of the cilia on the body, the thick rays in the fins, and hooks which are not serrated.Kassatkina, A. P. (2007)Review of the genera of the family Sagittidae with separation of a new subfamily and description of a new species of the genus ''Sagitta'' from the Sea of Japan (Chaetognatha).''Zoosystematica Rossica'', 16(2), 157-162. As of 2007 there are 15 species. More have since been described.Kassatkina, A. P. (2008)New species of the genus ''Sagitta sensu str''.(Chaetognatha) from the Sea of Japan with description of an original stain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chaetognatha
The Chaetognatha or chaetognaths (meaning ''bristle-jaws'') are a phylum of predatory marine worms that are a major component of plankton worldwide. Commonly known as arrow worms, about 20% of the known Chaetognatha species are benthic, and can attach to algae and rocks. They are found in all marine waters, from surface tropical waters and shallow tide pools to the deep sea and polar regions. Most chaetognaths are transparent and are torpedo shaped, but some deep-sea species are orange. They range in size from . There are more than 120 modern species assigned to over 20 genera. Despite the limited diversity of species, the number of individuals is large. Arrow worms are usually considered a type of protostome that do not belong to either Ecdysozoa or Lophotrochozoa. Anatomy Chaetognaths are transparent or translucent dart-shaped animals covered by a cuticle. The body is divided into a distinct head, trunk, and tail. There are between four and fourteen hooked, grasping spin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sagitta Kussakini
Sagitta is a dim but distinctive constellation in the northern sky. Its name is Latin for 'arrow', not to be confused with the significantly larger constellation Sagittarius 'the archer'. It was included among the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one of the 88 modern constellations defined by the International Astronomical Union. Although it dates to antiquity, Sagitta has no star brighter than 3rd magnitude and has the third-smallest area of any constellation. Gamma Sagittae is the constellation's brightest star, with an apparent magnitude of 3.47. It is an aging red giant star 90% as massive as the Sun that has cooled and expanded to a diameter 54 times greater than it. Delta, Epsilon, Zeta, and Theta Sagittae are each multiple stars whose components can be seen in small telescopes. V Sagittae is a cataclysmic variable—a binary star system composed of a white dwarf accreting mass of a donor star that is expected to g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sagitta Setosa
''Parasagitta setosa'' is a small arrow worm in the family Sagittidae, previously referred to as ''Sagitta setosa''. It is native to the northeastern Atlantic Ocean, the North Sea and the Mediterranean Sea, and also occurs in the Baltic Sea and the Black Sea. Description ''Parasagitta setosa'' grows to a maximum length of , its tail being up to a quarter of this length. It is a thin, transparent, flexible worm with two pairs of rounded lateral fins composed completely of ray-like structures. There are eight to nine curved grasping hooks on the head. The teeth are in two rows, with six to eight in the front row and ten to sixteen at the back. The eyes have a star-shaped segment spot and the collarette is small or not present at all. The seminal vesicles are very near the posterior fins which are separated from the caudal fin. Distribution ''Parasagitta setosa'' is a common neritic species forming part of the plankton in waters less than about 200 metres deep. It occurs in the n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sagitta Sceptrum
Sagitta is a dim but distinctive constellation in the northern sky. Its name is Latin for 'arrow', not to be confused with the significantly larger constellation Sagittarius 'the archer'. It was included among the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one of the 88 modern constellations defined by the International Astronomical Union. Although it dates to antiquity, Sagitta has no star brighter than 3rd magnitude and has the third-smallest area of any constellation. Gamma Sagittae is the constellation's brightest star, with an apparent magnitude of 3.47. It is an aging red giant star 90% as massive as the Sun that has cooled and expanded to a diameter 54 times greater than it. Delta, Epsilon, Zeta, and Theta Sagittae are each multiple stars whose components can be seen in small telescopes. V Sagittae is a cataclysmic variable—a binary star system composed of a white dwarf accreting mass of a donor star that is expected to g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
