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Heteromysis
''Heteromysis'' (from Greek ''heteros'' meaning ‘different’, and ''mysis'', a genus name ''Mysis'') is a genus of marine mysid crustaceans (opossum shrimps) from the family Mysidae, associated with various shallow-water invertebrates. The name describes differentiation of its pereiopods (thoracic appendages) as possible adaptation to commensal life-style. ''Heteromysis'' is one of the largest mysid genera, containing more than 100 species. The genus is distributed globally, but predominantly in tropical and subtropical waters. Description The body is rather moderately robust. Telson trapezoidal, apically with cleft. Eyes with well developed cornea. Pereiopod 1 carpopropodus always in possession of some either smooth or modified spiniform setae. Pereopod 2 carpopropodus multisegmented. Uropodal endopod with spiniform setae on its inner margin. Members of the genus are not known to share any unique characters. Compared to other genera of the subfamily Heteromysinae, ''He ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sidney Irving Smith
Sidney Irving Smith (February 18, 1843 in Norway, Maine – May 6, 1926 in New Haven, Connecticut) was an American zoologist. Private life Sidney Smith was the son of Elliot Smith and Lavinia Barton. His brother in law was Addison Emery Verrill. Smith married Eugenia Pocahontas Barber in New Haven, Connecticut on June 29, 1882. The couple had no children, and Eugenia died on March 14, 1916. Smith suffered from hereditary glaucoma, rendering him partially sighted from 1906, and completely blind some years before his death. He died on May 6, 1926 of throat cancer. Education and career In his youth, Sidney Irving Smith became expert on the fauna around his home town, and an expert at making collections, particularly of insects. He studied at the Sheffield Scientific School of Yale University, and received his Ph.B. in 1867. Yale University conferred upon him the honorary degree of M.A. in 1887. He stayed on at Yale, initially as an assistant, but from 1875 as the first professor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mysidae
Mysidae is the largest family (biology), family of crustaceans in the order (biology), order Mysida, with over 1000 species in around 170 genera. Characteristics Members of the family Mysidae are distinguished from other mysids by the fact that the first pereopod (walking leg) has a well-developed exopod (outer branch), the carpopropodus of the endopod (inner branch) of the 3rd to 8th pereopods is divided into sub-segments and there are statocysts on the endopod of the uropods (posterior appendages). Female petalophthalmidans have two or three oostegites (flexible bristly flaps) forming the base of the Brood pouch (Peracarida), marsupium or brood pouch under the thorax, apart from the subfamily Boreomysinae, which has seven pairs of oostegites. Subfamilies and genera The following subfamilies and genera are recognised: ;Boreomysinae Holt & Tattersall, 1905 *''Neobirsteiniamysis'' Hendrickx et Tchindonova, 2020 *''Boreomysis'' G. O. Sars, 1869 ;Erythropinae Hansen, 1910 *''Aberom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Animal
Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motility, able to move, can Sexual reproduction, reproduce sexually, and go through an ontogenetic stage in which their body consists of a hollow sphere of Cell (biology), cells, the blastula, during Embryogenesis, embryonic development. Over 1.5 million Extant taxon, living animal species have been Species description, described—of which around 1 million are Insecta, insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from to . They have Ecology, complex interactions with each other and their environments, forming intricate food webs. The scientific study of animals is known as zoology. Most living animal species are in Bilateria, a clade whose members have a Symmetry in biology#Bilate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature, also sometimes i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World Ocean
The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water. An ocean can also refer to any of the large bodies of water into which the world ocean is conventionally divided."Ocean." ''Merriam-Webster.com Dictionary'', Merriam-Webster, |
Brood Pouch (Peracarida)
The marsupium or brood pouch, is a characteristic feature of Peracarida, including the orders Amphipoda, Isopoda, Cladocera, and Cumacea. It is an egg chamber formed by oostegites, which are appendages that are attached to the coxae (first segment) of the first pereiopods. Females lay their eggs directly into the brood chamber, and the young will develop there, undergoing several moults before emerging as miniature adults referred to as mancae. Males have no marsupium. References {{malacostraca-stub Crustacean anatomy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uropod
Uropods are posterior appendages found on a wide variety of crustaceans. They typically have functions in locomotion. Definition Uropods are often defined as the appendages of the last body segment of a crustacean. An alternative definition suggested by Frederick R. Schram restricts the term to those structures arising from the segment before the anal segment (the segment which carries the anus). Under this latter definition, the appendages of the anal segment are caudal ramus, caudal rami, which are analogy (biology), analogous to uropods. Form Uropods are typically biramous – comprising an endopod and an exopod. The exopod is typically the larger, and may be divided in two by a transverse suture known as the diaeresis. The uropods may work in concert with the telson to form a "tail fan". References {{Reflist, 32em Crustacean anatomy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cornea
The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Along with the anterior chamber and lens, the cornea refracts light, accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is approximately 43 dioptres. The cornea can be reshaped by surgical procedures such as LASIK. While the cornea contributes most of the eye's focusing power, its focus is fixed. Accommodation (the refocusing of light to better view near objects) is accomplished by changing the geometry of the lens. Medical terms related to the cornea often start with the prefix "'' kerat-''" from the Greek word κέρας, ''horn''. Structure The cornea has unmyelinated nerve endings sensitive to touch, temperature and chemicals; a touch of the cornea causes an involuntary reflex to close the eyelid. Because transparency is of prime importance, the healthy cornea does not have or need blood vessels with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telson
The telson () is the posterior-most division of the body of an arthropod. Depending on the definition, the telson is either considered to be the final segment of the arthropod body, or an additional division that is not a true segment on account of not arising in the embryo from teloblast areas as other segments. It never carries any appendages, but a forked "tail" called the caudal furca may be present. The shape and composition of the telson differs between arthropod groups. Crustaceans In lobsters, shrimp and other decapods, the telson, along with the uropods, forms the tail fan. This is used as a paddle in the caridoid escape reaction ("lobstering"), whereby an alarmed animal rapidly flexes its tail, causing it to dart backwards. Krill can reach speeds of over 60 cm per second by this means. The trigger time to optical stimulus is, in spite of the low temperatures, only 55 milliseconds. In the Isopoda and Tanaidacea (superorder Peracarida), the last abdominal b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
