|
Littorina Planaxis
''Littorina'' is a genus of small sea snails, marine gastropod molluscs in the family Littorinidae, the winkles or periwinkles.WoRMS (2011). Littorina Férussac, 1822. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=138135 on 2011-04-15 These small snails live in the tidal zone of rocky shores. Overview In Europe there are about nine species in this genus, one of which is the rough periwinkle, ''Littorina saxatilis'' (Olivi, 1792). Another closely related (supposed) species ''Littorina tenebrosa'' (Montagu 1802) was thought to be distinct because of its different ecological requirements, but current studies have shown that it is not at all clear whether the two are indeed separate species or whether ''L. tenebrosa'' is perhaps merely an ecotype (an ecological form) of ''L. saxatilis''.Gosling, E.M. (2002). ''The periwinkle as a model in biodiversity studies: a geneticist's view.'' in Marine Biodiversity in Ireland an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latina, Lazio
Latina () is the capital of the province of Latina in the Lazio region, in central Italy. , the city has 126,612 inhabitants and is the second-largest city of the region, after the national capital Rome. It was founded in 1932 under the fascist administration, as Littoria, when the area surrounding it which had been a swamp since antiquity was drained. History Although the area was first settled by the Latins, the modern city was founded by Benito Mussolini on 30 June 1932 as Littoria, named for the fascio littorio. The city was inaugurated on 18 December of the same year. Littoria was populated with settlers coming mainly from Friuli and Veneto, who formed the so-called Venetian- Pontine community (today surviving only in some peripheral boroughs). The edifices and the monuments, mainly in rationalist style, were designed by famous architects and artists such as Marcello Piacentini, Angiolo Mazzoni and Duilio Cambellotti. In 1934 it became a provincial capital and, after Wor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Littorina Sea
Littorina Sea (also Litorina Sea) is a geological brackish water stage of the Baltic Sea, which existed around 7500–4000 BP and followed the Mastogloia Sea, a transitional stage of the Ancylus Lake. This stage and form of the body of water is named after common periwinkle (''Littorina littorea''), then a prevailing mollusc in the waters, which indicates its salinity. A transgression of the Baltic approximately 4500 BP widened its ocean link, allowing it to reach a peak of salinity during the warmer Atlantic period of European climatology. At this peak, the sea bore twice the volume of water and covered 26.5% more land than it does today. As the period ended, the features of the modern coast appeared, including lagoons, spits, and dunes. Notable exceptions include steep terraces such as the Øresund where the recession of sea level exposes less dry land. During the period, temperate deciduous forest Temperate deciduous or temperate broad-leaf forests are a variety of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Littorina Compressa
''Littorina compressa'' is a species of sea snail, a marine gastropod mollusk in the family Littorinidae The Littorinidae are a taxonomic family of over 200 species of sea snails, marine gastropod molluscs in the clade Littorinimorpha, commonly known as periwinkles and found worldwide. Names In English-speaking countries, gastropod molluscs from o ..., the winkles or periwinkles. References Littorinidae Gastropods described in 1865 {{Littorinidae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Littorina Brevicula
''Littorina brevicula'' is a species of sea snail, a marine gastropod mollusk in the family Littorinidae The Littorinidae are a taxonomic family of over 200 species of sea snails, marine gastropod molluscs in the clade Littorinimorpha, commonly known as periwinkles and found worldwide. Names In English-speaking countries, gastropod molluscs from o ..., the winkles or periwinkles. Description Distribution References Littorinidae Gastropods described in 1844 Marine gastropods {{Littorinidae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Littorina Arcana
''Littorina arcana'' is a species of sea snail, a marine gastropod mollusk in the family Littorinidae The Littorinidae are a taxonomic family of over 200 species of sea snails, marine gastropod molluscs in the clade Littorinimorpha, commonly known as periwinkles and found worldwide. Names In English-speaking countries, gastropod molluscs from o ..., the winkles or periwinkles. Description Distribution References Littorinidae Gastropods described in 1978 {{Littorinidae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Littorina Aleutica
''Littorina aleutica'' is a species of sea snail, a marine gastropod mollusk in the family Littorinidae The Littorinidae are a taxonomic family of over 200 species of sea snails, marine gastropod molluscs in the clade Littorinimorpha, commonly known as periwinkles and found worldwide. Names In English-speaking countries, gastropod molluscs from o ..., the winkles or periwinkles. Distribution Locality: Aleutian Islands, Fox Islands, Akutan Pass, Alaska, United States, North Pacific Ocean References Littorinidae Marine molluscs of North America Fauna of Alaska Aleutian Islands Molluscs of the United States Gastropods described in 1872 Endemic fauna of Alaska {{Littorinidae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
George Washington Tryon
George Washington Tryon Jr. (20 May 1838 – 5 February 1888) was an American malacologist who worked at the Academy of Natural Sciences in Philadelphia. Biography George Washington Tryon was the son of Edward K. Tryon and Adeline Savidt. In 1853 he attended the Friends Central School in Philadelphia. In 1859, Tryon became a member of the Academy of Natural Sciences of Philadelphia. He was largely responsible for the construction of new buildings for the Academy, especially, in 1866, a section for malacology. In 1869 he became the conservator in this malacological section. In 1865, together with a group of American malacologists, he founded (and financed) the American Journal of Conchology. This ended in 1872. In 1879 he started the ''Manual of Conchology; structural and systematic; with illustrations of the species'', volume 1, series 1. When he died, nine volumes of the first series had been published. From 1887 until 1888, his assistant was Henry Augustus Pilsbry. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radula
The radula (, ; plural radulae or radulas) is an anatomical structure used by molluscs for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus. The radula is unique to the molluscs, and is found in every class of mollusc except the bivalves, which instead use cilia, waving filaments that bring minute organisms to the mouth. Within the gastropods, the radula is used in feeding by both herbivorous and carnivorous snails and slugs. The arrangement of teeth ( denticles) on the radular ribbon varies considerably from one group to another. In most of the more ancient lineages of gastropods, the radula is used to graze, by scraping diatoms and other microscopic algae off rock surfaces and other substrates. Predatory marine snails such as the Naticidae use the radula plus an acidic secretion to bore through the shell of other molluscs. Other predatory marine snails ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operculum (gastropod)
The operculum (; ) is a corneous or calcareous anatomical structure like a trapdoor that exists in many (but not all) groups of sea snails and freshwater snails, and also in a few groups of land snails; the structure is found in some marine and freshwater gastropods, and in a minority of terrestrial gastropods, including the families Helicinidae, Cyclophoridae, Aciculidae, Maizaniidae, Pomatiidae, etc. The operculum is attached to the upper surface of the foot and in its most complete state, it serves as a sort of "trapdoor" to close the aperture of the shell when the soft parts of the animal are retracted. The shape of the operculum varies greatly from one family of gastropods to another. It is fairly often circular, or more or less oval in shape. In species where the operculum fits snugly, its outline corresponds exactly to the shape of the aperture of the shell and it serves to seal the entrance of the shell. Many families have opercula that are reduced in size, and which a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Columella (gastropod)
The columella (meaning "little column") or (in older texts) pillar is a central anatomical feature of a coiled snail shell, a gastropod shell. The columella is often only clearly visible as a structure when the shell is broken, sliced in half vertically, or viewed as an X-ray image. The columella runs from the apex of the shell to the midpoint of the undersurface of the shell, or the tip of the siphonal canal in those shells which have a siphonal canal. If a snail shell is visualized as a cone of shelly material which is wrapped around a central axis, then the columella more or less coincides spatially with the central axis of the shell. In the case of shells that have an umbilicus, the columella is a hollow structure. The columella of some groups of gastropod shells can have a number of plications or folds (the columellar fold, plaits or plicae), which are usually visible when looking to the inner lip into the aperture of the shell. These folds can be wide or narrow, prominent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aperture (mollusc)
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where the head-foot part of the body of the animal emerges for locomotion, feeding, etc. The term ''aperture'' is used for the main opening in gastropod shells, scaphopod shells, and also for ''Nautilus'' and ammonite shells. The word is not used to describe bivalve shells, where a natural opening between the two shell valves in the closed position is usually called a ''gape''. Scaphopod shells are tubular, and thus they have two openings: a main anterior aperture and a smaller posterior aperture. As well as the aperture, some gastropod shells have additional openings in their shells for respiration; this is the case in some Fissurellidae (keyhole limpets) where the central smaller opening at the apex of the shell is called an orifice, and in the Haliotidae (abalones) where the row of respiratory openings in the shell are also called orifices. In gastropods In some prosobranch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whorl (mollusc)
A whorl is a single, complete 360° revolution or turn in the spiral growth of a mollusc shell. A spiral configuration of the shell is found in numerous gastropods, but it is also found in shelled cephalopods including ''Nautilus'', ''Spirula'' and the large extinct subclass of cephalopods known as the ammonites. A spiral shell can be visualized as consisting of a long conical tube, the growth of which is coiled into an overall helical or planispiral shape, for reasons of both strength and compactness. The number of whorls which exist in an adult shell of a particular species depends on mathematical factors in the geometric growth, as described in D'Arcy Wentworth Thompson's classic 1917 book ''On Growth and Form'', and by David Raup. The main factor is how rapidly the conical tube expands (or flares-out) over time. When the rate of expansion is low, such that each subsequent whorl is not that much wider than the previous one, then the adult shell has numerous whorls. When the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_torquata_002.jpg "Click for more on -> Operculum (gastropod)")
