|
Apex (mollusc)
In anatomy, an apex ( adjectival form: apical) is part of the shell of a mollusk. The apex is the pointed tip (the oldest part) of the shell of a gastropod, scaphopod, or cephalopod. The apex is used in end-blown conches. Gastropods The word "apex" is most often used to mean the tip of the spire of the shell of a gastropod. The apex is the first-formed, and therefore the oldest, part of the shell. To be more precise, the apex would usually be where the tip of the embryonic shell or protoconch is situated, if that is still present in the adult shell (often it is lost or eroded away). Coiled gastropod shells The phrase apical whorls, or protoconch, means the whorls that constitute the embryonic shell at the apex of the shell, especially when this is clearly distinguishable from the later whorls of the shell, otherwise known as the teleoconch. Comparison of the apical part and the whole shell of ''Otukaia kiheiziebisu'': File:Calliostoma kiheiziebisu apex.png File:Calliostoma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adjectival Form
In linguistics, an adjective (abbreviated ) is a word that generally modifies a noun or noun phrase or describes its referent. Its semantic role is to change information given by the noun. Traditionally, adjectives were considered one of the main parts of speech of the English language, although historically they were classed together with nouns. Nowadays, certain words that usually had been classified as adjectives, including ''the'', ''this'', ''my'', etc., typically are classed separately, as determiners. Here are some examples: * That's a funny idea. (attributive) * That idea is funny. ( predicative) * * The good, the bad, and the funny. ( substantive) Etymology ''Adjective'' comes from Latin ', a calque of grc, ἐπίθετον ὄνομα, epítheton ónoma, additional noun (whence also English ''epithet''). In the grammatical tradition of Latin and Greek, because adjectives were inflected for gender, number, and case like nouns (a process called declension), they were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patellidae
Patellidae is a taxonomic family of sea snails or true limpets, marine gastropod molluscs in the clade Patellogastropoda. (The superfamily Patelloidea should not be confused with the similar-sounding genus of true limpets '' Patelloida'' which is in the family Lottiidae within the superfamily Lottioidea, also part of the Patellogastropoda.) Taxonomy A cladogram showing phylogenic relations of Patellogastropoda based on molecular phylogeny research by Nakano & Ozawa (2007):Nakano T. & Ozawa T. (2007). "Worldwide phylogeography of limpets of the order Patellogastropoda: Molecular, morphological and palaeontological evidence". ''Journal of Molluscan Studies'' 73(1) 79-99. . Genera Genera and species in the family Patellidae include: * † '' Berlieria'' de Loriol, 1903 * ''Cymbula'' H. & A. Adams, 1854 * ''Helcion'' Montfort, 1810 * ''Patella'' Linnaeus, 1758 * † '' Proscutum'' P. Fischer, 1885 * ''Scutellastra'' H. Adams & A. Adams, 1854 ;Synonyms: * ''Ancistromesus'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusc Shells
The mollusc (or molluskOften spelled mollusk shell in the USA; the spelling "mollusc" are preferred by ) shell is typically a calcareous exoskeleton which encloses, supports and protects the soft parts of an animal in the phylum Mollusca, which includes snails, clams, tusk shells, and several other classes. Not all shelled molluscs live in the sea; many live on the land and in freshwater. The ancestral mollusc is thought to have had a shell, but this has subsequently been lost or reduced on some families, such as the squid, octopus, and some smaller groups such as the caudofoveata and solenogastres. Today, over 100,000 living species bear a shell; there is some dispute as to whether these shell-bearing molluscs form a monophyletic group (conchifera) or whether shell-less molluscs are interleaved into their family tree. Malacology, the scientific study of molluscs as living organisms, has a branch devoted to the study of shells, and this is called conchology—although these ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prodissoconch
A prodissoconch (meaning first or earliest or original shell) is an embryonic or larval shell which is present in the larva of a bivalve mollusk (clams, scallops, oysters, etc.). (The homologous structure in gastropods (snails) is called the protoconch.) The prodissoconch is often but not always smooth, and has no growth lines. It is sometimes still present and visible in the adult shell, if there has been no erosion of the shell in that area. The structure of the prodissoconch has been widely used as a discriminating feature in bivalve systematics. Position Once the larval bivalve settles and becomes a juvenile, the rest of the shell starts to grow. The earliest part of the shell that formed often shows in the adult shell as a protruding area known as the umbo, at the tip of which is the prodissoconch, assuming it has not been eroded or obscured in some other way. Quite often there is a visible line of demarkation where the prodissoconch ends and the umbo begins, and there ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beak (bivalve)
The beak is part of the shell of a bivalve mollusk, i.e. part of the shell of a saltwater or freshwater clam. The beak is the basal projection of the oldest part of the valve of the adult animal. The beak usually, but not always, coincides with the umbo, the highest and most prominent point on the valve. Because by definition, all bivalves have two valves, the shell of a bivalve has two umbones, and two beaks. In many species of bivalves the beaks point towards one another. However, in some species of bivalves the beaks point posteriorly, in which case they are referred to as opisthogyrate; in others the beaks point forward, and are described as being prosogyrate. If the beak is not eroded or worn down at all, it may still be capped with the prodissoconch A prodissoconch (meaning first or earliest or original shell) is an embryonic or larval shell which is present in the larva of a bivalve mollusk (clams, scallops, oysters, etc.). (The homologous structure in gastropods (s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Umbo (bivalve)
The umbo (plural umbones or umbos) is the vaguely defined, often most prominent, highest part of each valve of the shell of a bivalve or univalve mollusc. It usually contains the valve's beak, the oldest point of the valve, and its degree of prominence and position relative to the hinge line are sometimes helpful in distinguishing bivalve taxa. The umbo forms while the animal is a juvenile, and radial growth subsequently proceeds around that area. The umbo is situated above the hinge line. In those bivalves where the umbones do not protrude, as is the case for example in some mussels, the umbones can nonetheless usually be readily identified by examining the concentric growth lines of the shell. Umbo is also in use in anatomic descriptions of brachiopod Brachiopods (), phylum Brachiopoda, are a phylum of trochozoan animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bivalve
Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of marine and freshwater Mollusca, molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bivalves have no head and they lack some usual molluscan organs, like the radula and the odontophore. They include the clams, oysters, Cockle (bivalve), cockles, mussels, scallops, and numerous other family (biology), families that live in saltwater, as well as a number of families that live in freshwater. The majority are filter feeders. The gills have evolved into Ctenidium (mollusc), ctenidia, specialised organs for feeding and breathing. Most bivalves bury themselves in sediment, where they are relatively safe from predation. Others lie on the sea floor or attach themselves to rocks or other hard surfaces. Some bivalves, such as the scallops and file shells, can nekton, swim. The shipworms bore into wood, clay, or ... [...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 prosob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orthocone
An orthocone is an unusually long straight shell of a nautiloid cephalopod.; During the 18th and 19th centuries, all shells of this type were named '' Orthoceras'', creating a wastebasket taxon, but it is now known that many groups of nautiloids developed or retained this type of shell. An orthocone can be thought of as like a '' nautilus'', but with the shell straight and uncoiled. It was previously believed that these represented the most primitive form of nautiloid, but it is now known that the earliest nautiloids had shells that were slightly curved. An orthoconic form evolved several times among cephalopods, and among nautiloid cephalopods is prevalent among the ellesmerocerids, endocerids, actinocerids, orthoceratoids, and bactritids. Orthocones existed from the Late Cambrian to the Late Triassic, but they were most common in the early Paleozoic. Revivals of the orthocone design later occurred in other cephalopod groups, notably baculitid ammonites in the Cretaceo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otukaia Kiheiziebisu
''Otukaia kiheiziebisu'' is a species of sea snail, a marine gastropod mollusk in the family Calliostomatidae. The type specimens were collected by amateur conchologist Mr. Kiheizi Oosima in 1938. The specific name ''kiheiziebisu'' is in honour of him. The new species was originally described as ''Calliostoma kiheiziebisu'' by the Japanese malacologist Yanosuke Otuka (1903-1950) in 1939. ''Otukaia kiheiziebisu'' is the type species of the genus '' Otukaia'' Ikeba, 1942. Some authors recognize ''Otukaia'' as a separate genus.Vilvens & Sellanes (2006). '' The Nautilus'' 120(1): 15-20. Description The shell is large, conical, thin, semitransparent, pale cinnamon pink in colour with pearly lustre. The shell has 8.5 whorls. One and a half coils of nuclear portion of whorls are rounded in outline, smooth, polished on the surface. Subsequent whorls are sculptured with four strong, beaded spiral keels and very fine lines, which are only visible under a magnifying lens, and with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusc Shell
The mollusc (or molluskOften spelled mollusk shell in the USA; the spelling "mollusc" are preferred by ) shell is typically a calcareous exoskeleton which encloses, supports and protects the soft parts of an animal in the phylum Mollusca, which includes snails, clams, tusk shells, and several other classes. Not all shelled molluscs live in the sea; many live on the land and in freshwater. The ancestral mollusc is thought to have had a shell, but this has subsequently been lost or reduced on some families, such as the squid, octopus, and some smaller groups such as the caudofoveata and solenogastres. Today, over 100,000 living species bear a shell; there is some dispute as to whether these shell-bearing molluscs form a monophyletic group (conchifera) or whether shell-less molluscs are interleaved into their family tree. Malacology, the scientific study of molluscs as living organisms, has a branch devoted to the study of shells, and this is called conchology—although ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
