A display of seashells, mostly of marine Mollusca, including an abalone, nautilus, ark shell, scallop, pearl oyster, auger shell, cone shell, two cowries, a hammer oyster, and a fossil clam, but also including the shell or test of a sand dollar (an echinoderm).

A seashell is the common name for a hard, protective outer layer created by a marine organism or sea creature. In addition to seashells, there are also several different types of non-marine animal shell in the natural world. Image File history File links Size of this preview: 786 × 599 pixelsFull resolution (2500 × 1906 pixel, file size: 2. ... Image File history File links Size of this preview: 786 × 599 pixelsFull resolution (2500 × 1906 pixel, file size: 2. ... Classes Caudofoveata Aplacophora Polyplacophora Monoplacophora Bivalvia Scaphopoda Gastropoda Cephalopoda † Rostroconchia † Helcionelloida † ?Bellerophontidae The molluscs (British spelling) or mollusks (American spelling) are members of the large and diverse phylum Mollusca, which includes a variety of familiar animals well-known for their decorative shells or as seafood. ... Species Many, see species section. ... Genera Allonautilus Nautilus Nautilus (from Greek ναυτίλος, sailor) is the common name of any marine creatures of the cephalopod family Nautilidae, the sole family of the suborder Nautilina. ... Genera See text Ark clams are bivalve molluscs of the family Arcidae. ... Genera See text. ... Species Pinctada maxima Pinctada margaritifera Pinctada fucata Pinctada radiata Pinctada albina Pinctada virens Pinctada chemnitzi Pinctada maculata Pinctada nigra Pinctada atropurpurea Pinctada laosensis Pinctada martensi The Pearl Oysters are the genus Pinctada of bivalve molluscs. ... Genera See text. ... Genera Asprella Chelyconus Conus Floraconus Leptoconus The cone snails or cone shells (family Conidae) are marine snails found in coral reefs. ... Species See text. ... For other uses, see Fossil (disambiguation). ... For other uses, see Clam (disambiguation). ... Suborders Laganina Rotulina Scutellina Sand dollars are in the Echinoid (Echinoderms) class of marine animals. ... Classes Subphylum Homalozoa Gill & Caster, 1960 Class Homostelea Class Homoiostelea Class Stylophora Gill & Caster, 1960 Class Ctenocystoidea Robison & Sprinkle, 1969 Subphylum Crinozoa Class Eocrinoidea Jaekel, 1899 Class Paracrinoidea Regnéll, 1945 Class Cystoidea von Buch, 1846 Class Blastoidea Class Crinoidea Subphylum Asterozoa Class Ophiuroidea Class Asteroidea Subphylum Echinozoa Helicoplacoidea †  ?Arkarua... Marine is an umbrella term for things relating to the ocean, as with marine biology, marine geology, and as a term for a navy, etc. ... “Life on Earth” redirects here. ... Various seashells Danielle A shell is the hard, rigid outer covering, or integument, allanimals. ...

Seashells are very often found in beach drift, which is deposited along strandlines on beaches. These shells are often washed up empty and clean, the animal having already died, and the soft parts having rotted away or having been eaten by other creatures. This is how most shells are found by beachcombers, and collecting these shells is a harmless hobby. However, the majority of seashells which are offered for sale commercially have been collected live, killed and cleaned specifically for the commercial trade, and this type of exploitation can sometimes have a strong negative impact on rarer species, and on local ecosystems. For other uses, see Beach (disambiguation). ... Beachcombing or Beachcomber is a term with multiple but related meanings which have evolved over time. ... A coral reef near the Hawaiian islands is an example of a complex marine ecosystem. ...

The kind of seashells which are perhaps most familiar, and most commonly encountered, both in the wild and for sale as decorative objects, are the external shells of marine mollusks. These are usually primarily composed of calcium carbonate, in the form of calcite or aragonite crystallised out in an organic matrix. Calcium carbonate in mollusk shells can take different crystalline forms, one being nacre, otherwise known as mother of pearl. Marine is an umbrella term for things relating to the ocean, as with marine biology, marine geology, and as a term for a navy, etc. ... Classes Caudofoveata Aplacophora Polyplacophora Monoplacophora Bivalvia Scaphopoda Gastropoda Cephalopoda † Rostroconchia The mollusks or molluscs are the large and diverse phylum Mollusca, which includes a variety of familiar creatures well-known for their decorative shells or as seafood. ... Calcium carbonate is a chemical compound, with the chemical formula CaCO3. ... Doubly refracting Calcite from Iceberg claim, Dixon, New Mexico. ... Aragonite Aragonite is a polymorph of the mineral calcite, both having the chemical composition CaCO3. ... “Mother of Pearl” redirects here. ...

Other kinds of sea animals have exoskeletons or shells which may after death be found in beach drift and picked up by beachcombers, and these include other invertebrate remains such as crab shells, horseshoe crab shells, and sea urchin tests. An exoskeleton is an external anatomical feature that supports and protects an animals body, in contrast to the internal endoskeleton of, for example, a human. ... Invertebrate is an English word that describes any animal without a spinal column. ... Superfamilies Dromiacea Homolodromioidea Dromioidea Homoloidea Eubrachyura Raninoidea Cyclodorippoidea Dorippoidea Calappoidea Leucosioidea Majoidea Hymenosomatoidea Parthenopoidea Retroplumoidea Cancroidea Portunoidea Bythograeoidea Xanthoidea Bellioidea Potamoidea Pseudothelphusoidea Gecarcinucoidea Cryptochiroidea Pinnotheroidea * Ocypodoidea * Grapsoidea * An asterisk (*) marks the crabs included in the clade Thoracotremata. ... Binomial name Linnaeus, 1758 The horseshoe crab, horsefoot, king crab, or sauce-pan (Limulus polyphemus, formerly known as Limulus cyclops, Xiphosura americana, Polyphemus occidentalis) is a chelicerate arthropod. ... Subclasses Euechinoidea Superorder Atelostomata Order Cassiduloida Order Spatangoida (heart urchins) Superorder Diadematacea Order Diadematoida Order Echinothurioida Order Pedinoida Superorder Echinacea Order Arbacioida Order Echinoida Order Phymosomatoida Order Salenioida Order Temnopleuroida Superorder Gnathostomata Order Clypeasteroida (sand dollars) Order Holectypoida Perischoechinoidea Order Cidaroida (pencil urchins) Sea urchins are small spiny sea creatures...

Despite this variety of shells, it is quite often the case that only the shells of marine molluscs, (spelled "mollusks" in the USA), are meant when the word seashells is used. Classes Caudofoveata Aplacophora Polyplacophora - Chitons Monoplacophora Bivalvia - Bivalves Scaphopoda - Tusk shells Gastropoda - Snails and Slugs Cephalopoda - Squids, Octopuses, etc. ...

Mollusc shells

Main article: Gastropod shell

Main article: Bivalve shell

The marine gastropod Cypraea chinensis, the Chinese Cowry, showing partially extended mantle

The majority of shell-forming molluscs belong to two classes: Gastropoda (univalves, or snails) and Bivalvia (bivalves or clams, oysters, scallops, etc). There are, in addition, three other classes of mollusks which routinely create a shell, and those are: Scaphopoda (tusk shells), Polyplacophora (chitons, which have eight articulating shelly plates), and Monoplacophora (single-shelled chiton-like animals which live in very deep water, and which superficially resemble minute limpets. Shell of Zonitoides nitidus has dextral coiling. ... Image File history File links Download high resolution version (1788x1188, 1141 KB) Cypraea chinensis with partially extended mantle. ... Image File history File links Download high resolution version (1788x1188, 1141 KB) Cypraea chinensis with partially extended mantle. ... Look up class in Wiktionary, the free dictionary. ... Subclasses Eogastropoda (True Limpets and relatives) Orthogastropoda The gastropods, also previously known as gasteropods, or univalves, and more commonly known as snails and slugs, are the largest and most successful class of mollusks, with 60,000-75,000 known living species. ... Subclasses Anomalosdesmata Cryptodonta Heterodonta Paleoheterodonta Palaeotaxodonta Pteriomorphia and see text Mussels in the intertidal zone in Cornwall, England. ... Orders Dentaliida Gadilida The tusk shells are a class Scaphopoda of marine mollusks distinguished by curved tubular shells open at both ends, resembling a elephants tusk (thus the name). ... Lined Chiton (Tonicella lineata) Chitons, also called polyplacophorans and rarely polyplacophores, are 860 species of molluscs of the Class Polyplacophora. ... Orders Cyrtonellida Tryblidiida Pelagiellida Monoplacophora is a class of mollusks thought to be extinct until April 1952, when a living animal was dredged up from deep marine sediments in the Middle America Trench off the Pacific coast of Costa Rica, and named Neopilina by its discoverer, Danish biologist Dr. Henning...

Nautilus belauensis is one of only 6 extant cephalopod species which have an external shell

Nautiluses are the only extant cephalopods which have an external shell, although octopuses, cuttlefish and squid (especially Spirula spirula), have small internal shells. Females of the octopus genus Argonauta secrete a specialised paper-thin eggcase in which they partially reside, and this is popularly regarded as a shell, although it is not attached to the body of the animal. Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (2048 × 1536 pixel, file size: 111 KB, MIME type: image/jpeg) Nautilus from the side. ... Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (2048 × 1536 pixel, file size: 111 KB, MIME type: image/jpeg) Nautilus from the side. ... Binomial name Saunders, 1981 The Palau Nautilus (Nautilus belauensis) is a species of nautilus native to the waters around the Pacific island nation of Palau. ... Genera Allonautilus Nautilus Nautilus (from Greek ναυτίλος, sailor) is the common name of any marine creatures of the cephalopod family Nautilidae, the sole family of the suborder Nautilina. ... Orders Subclass Nautiloidea †Plectronocerida †Ellesmerocerida †Actinocerida †Pseudorthocerida †Endocerida †Tarphycerida †Oncocerida †Discosorida Nautilida †Orthocerida †Ascocerida †Bactritida Subclass †Ammonoidea †Goniatitida †Ceratitida †Ammonitida Subclass Coleoidea †Belemnoidea †Aulacocerida †Belemnitida †Hematitida †Phragmoteuthida Neocoleoidea (most living cephalopods) ?†Boletzkyida Sepiida Sepiolida Spirulida Teuthida Octopoda Vampyromorphida The cephalopods (Greek plural (kephalópoda); head-foot) are the mollusk class... For other uses, see Octopus (disambiguation). ... Orders and Families †Vasseuriina †Vasseuriidae †Belosepiellidae Sepiina †Belosaepiidae Sepiadariidae Sepiidae Cuttlefish are marine animals of the order Sepiida belonging to the Cephalopoda class (which also includes squid, octopuses, and nautiluses). ... For other uses, see Squid (disambiguation). ... Binomial name (Linnaeus, 1758) Synonyms Nautilus spirula Linnaeus, 1758 The Rams Horn Squid (Spirula spirula) is a cephalopod, the only extant member of the family Spirulidae, and order Spirulida. ... Species Argonauta argo Argonauta bottgeri Argonauta cornuta Argonauta hians Argonauta nodosa Argonauta nouryi Argonauta pacifica Argonauts (genus Argonauta, the only genus in the Argonautidae family) are a kind of pelagic octopus that live close to the surface of warm seas rather than on the sea floor, as nearly all other...

Malacology, the scientific study of molluscs as living organisms, has a branch devoted to shells, called conchology - although it should be noted that these terms used to be, and to a minor extent still are, used interchangeably, even by scientists (this is more common in Europe). Classes Caudofoveata Aplacophora Polyplacophora - Chitons Monoplacophora Bivalvia - Bivalves Scaphopoda - Tusk shells Gastropoda - Snails and Slugs Cephalopoda - Squids, Octopuses, etc. ... Conchology is the scientific study of shells of mollusks, a branch of malacology. ...

Creating the shell

In those mollusks which have a shell, the shell grows gradually over the lifetime of the mollusc by the addition of calcium carbonate to the leading edge or opening, and thus the shell gradually becomes longer and wider, in an increasing spiral shape, to better accommodate the growing animal inside. The animal also thickens the shell as it grows, so that the shell stays proportionately strong for its size.

The giant clam (Tridacna gigas) is the largest extant bivalve

A mollusk shell is formed, repaired and maintained by a part of the anatomy called the mantle. Any injuries to or abnormal conditions of the mantle are usually reflected in the shape and form and even color of the shell. When the animal encounters harsh conditions which limit its food supply, or otherwise cause it to become dormant for a while, the mantle often ceases to produce the shell substance. When conditions improve again and the mantle resumes its task, a "growth line" which extends the entire length of the shell is produced, and the pattern and even the colors on the shell after these dormant periods are sometimes quite different from previous colors and patterns. Giant clam or Tridacna gigas. ... Giant clam or Tridacna gigas. ... Binomial name Linnaeus, 1758 The giant clam (Tridacna gigas) or traditionally, pa’ua, is the largest living bivalve mollusc. ... The mantle is an organ found in mollusks. ...

Interestingly, within some species of mollusk there is often a surprising degree of variation in the exact shape, pattern, ornamentation, and color of the shell.

Composition of mollusc shells

Fossil shell covered in calcite crystals

Shells are composite materials of calcium carbonate, found either as calcite or aragonite and organic macromolecules, mainly proteins and polysaccharides. Shells can have numerous ultrastructural motifs, the most common being crossed-lamellar (aragonite), prismatic (aragonite or calcite), homogeneous (aragonite), foliated (aragonite) and nacre (aragonite). Although not the most common, the nacre is the most studied layer. Shells of the class Polyplacophora are made of aragonite Image File history File links Size of this preview: 800 × 582 pixelsFull resolution (2500 × 1818 pixel, file size: 2. ... Image File history File links Size of this preview: 800 × 582 pixelsFull resolution (2500 × 1818 pixel, file size: 2. ... For other uses, see Fossil (disambiguation). ... Doubly refracting Calcite from Iceberg claim, Dixon, New Mexico. ... For other uses, see Crystal (disambiguation). ... Doubly refracting Calcite from Iceberg claim, Dixon, New Mexico. ... Aragonite Aragonite is a polymorph of the mineral calcite, both having the chemical composition CaCO3. ... “Mother of Pearl” redirects here. ... Lined Chiton (Tonicella lineata) Chitons, also called polyplacophorans and rarely polyplacophores, are 860 species of molluscs of the Class Polyplacophora. ... Aragonite Aragonite is a polymorph of the mineral calcite, both having the chemical composition CaCO3. ...

Mollusc shells (especially those formed by marine species) are very durable and outlast the otherwise soft-bodied animals that produce them by a very long time (sometimes thousands of years). They fossilize easily, and fossil mollusc shells date all the way back to the Cambrian period. Large amounts of shells sometimes form sediment, and over geological time spans can become compressed into limestone deposits. For other uses, see Cambrian (disambiguation). ... For other uses, see Limestone (disambiguation). ...

Mother of pearl and pearl formation

Nacre, also known as mother of pearl, is an important part of the shell structure in many gastropod and bivalve mollusks especially the more ancient families such as top shells and pearl oysters. Like the other calcareous layers of the shell, the nacre is created by the epithelial cells (formed by the germ layer ectoderm) of the mantle tissue. Mollusk blood is rich in dissolved calcium, and during shell deposition, the calcium is concentrated out from the blood and crystallized as calcium carbonate. Nacre is continually deposited onto the inner surface of the animal's shell (the iridescent nacreous layer or mother of pearl). This is done both as a means to thicken, strengthen and smooth the inner surface of the shell itself and as a defense against parasitic organisms and damaging detritus. “Mother of Pearl” redirects here. ... In zootomy, epithelium is a tissue composed of a layer of cells. ... The ectoderm is outermost of the three germ layers of the developing embryo, the other two being the mesoderm and the endoderm. ... Human blood smear: a - erythrocytes; b - neutrophil; c - eosinophil; d - lymphocyte. ... For other uses, see Calcium (disambiguation). ... A parasite is an organism that spends a significant portion of its life in or on the living tissue of a host organism and which causes harm to the host without immediately killing it. ... Detritus may refer to: In geology, detritus is the name for loose fragments of rock that have been worn away by erosion. ...

When a mollusc is invaded by a parasite or is irritated by a foreign object that the animal cannot eject, a process known as encystation entombs the offending entity in successive, concentric layers of inner shell material, which in some cases is nacre. This process eventually forms what we call pearls and continues for as long as the mollusk lives. Almost any species of bivalve or gastropod is capable of producing "pearls", even mollusks which have no inner nacreous layer. However, only a few species, such as the famous pearl oysters, can create pearls which are highly prized. A parasite is an organism that spends a significant portion of its life in or on the living tissue of a host organism and which causes harm to the host without immediately killing it. ... For other uses, see Pearl (disambiguation). ... Species Pinctada maxima Pinctada margaritifera Pinctada fucata Pinctada radiata Pinctada albina Pinctada virens Pinctada chemnitzi Pinctada maculata Pinctada nigra Pinctada atropurpurea Pinctada laosensis Pinctada martensi The Pearl Oysters are the genus Pinctada of bivalve molluscs. ...

Non-marine mollusks

The white-lipped snail (Cepaea hortensis) is a pulmonate land snail

In fresh water shell-bearing mollusks are represented by families from the orders Unionoida (freshwater mussels) and Veneroida (clams), as well as the class Gastropoda (snails). Image File history File links Download high resolution version (1398x1816, 393 KB) Summary A yellow snail, species Cepaea hortensis? Image by Every1blowz, Kirkland, Washington, May 24, 2006. ... Image File history File links Download high resolution version (1398x1816, 393 KB) Summary A yellow snail, species Cepaea hortensis? Image by Every1blowz, Kirkland, Washington, May 24, 2006. ... Binomial name Cepaea hortensis (Müller, 1774) The white-lipped snail (Cepaea hortensis) is a very close relative of the grove snail. ... Suborders Systellommatophora Basommatophora Eupulmonata The Pulmonata are an order (once a subclass) of snails and slugs that have developed a pallial lung and thus can breathe air. ... For the village on the Isle of Wight, see Freshwater, Isle of Wight. ... The Unionoida is a taxonomic category, an order within the class Bivalvia. ... Families Arcticidae Astartidae Cardiidae Donacidae Kelliidae Lasaeidae Leptonidae Lucinidae Mactridae Montacutidae Petricolidae Pharidae Psammobiidae Scrobiculariidae Semelidae Solecurtidae Solenidae Tellinidae Thyasiridae Turtoniidae Ungulinidae Veneridae The Veneroida or veneroids are an order of bivalve molluscs. ... Subclasses Eogastropoda (True Limpets and relatives) Orthogastropoda The gastropods, also previously known as gasteropods, or univalves, and more commonly known as snails and slugs, are the largest and most successful class of mollusks, with 60,000-75,000 known living species. ... For other uses, see Snail (disambiguation). ...

The class Gastropoda also includes many land snails, most of which are pulmonates and breathe air. Although the great majority of land snails are small and inconspicuous, the large and highly-colored shells of some tropical species are prized by collectors. In certain tropical islands such as Cuba, or Papua New Guinea, there are almost as many species of land snails as there are of marine. Land snails cannot disperse very easily, so populations frequently become isolated from each other, resulting in situations where adjacent islands, or even adjacent valleys separated by hills or mountains, contain closely-related but clearly separate species of land snails.

Seashell collecting as a hobby

Both the science of studying mollusk shells and the hobby of collecting and classifying them are known as conchology -- the line between professional and amateur enthusiasts is often quite blurry. Conchology is the scientific study of shells of mollusks, a branch of malacology. ...

Shells of marine molluscs (some of which wash up on beaches or live in the intertidal or sub-tidal zones and are therefore easily found without specialized equipment) are collected by a large number of enthusiasts. Many shell collectors find their own material or are interested in "specimen shells": shells in good condition which come with full scientific collecting data: information including how, when, where, in what habitat, and by whom, they were collected.

In the tropical and sub-tropical areas of the planet, there are far more species of colorful, large, and intertidally-dwelling seashells than there are in the temperate zones and the regions closer to the poles.

Other sea creatures

Echinothrix calamaris, a species of sea urchin

The light-blue Soldier Crab (Mictyris longicarpus)

Marine diatoms form hard silicate shells

The brachiopods, or lamp shells, superficially resemble clams, but the phylum is completely unrelated to molluscs. Most lines of brachiopods were ended during the Permian-Triassic extinction event, and their ecological niche filled by bivalves. Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (1632 × 1224 pixel, file size: 1. ... Image File history File links Metadata Size of this preview: 800 × 600 pixelsFull resolution (1632 × 1224 pixel, file size: 1. ... Binomial name Pallas, 1774 The double spined urchin or banded sea urchin, Echinothrix calamaris, is a urchin, with a test (shell) diameter of about 5 cm. ... Image File history File linksMetadata Download high resolution version (1099x921, 419 KB) Summary Light-blue Soldier Crab (Mictyris longicarpus), faimly Mictyridae. ... Image File history File linksMetadata Download high resolution version (1099x921, 419 KB) Summary Light-blue Soldier Crab (Mictyris longicarpus), faimly Mictyridae. ... Species Mictyris brevidactylus Mictyris longicarpus Mictyris platycheles Mictyris is a genus of brightly coloured crabs, placed in its own taxonomical family, the Mictyridae. ... Image File history File links Beautiful marine diatoms as seen through a microscope. ... Image File history File links Beautiful marine diatoms as seen through a microscope. ... Orders Centrales Pennales Diatoms (Greek: (dia) = through + (temnein) = to cut, i. ... Subphyla and classes See Classification Brachiopods (from Latin brachium, arm + New Latin -poda, foot) are a phylum of animals. ... The Permian-Triassic (P-T or PT) extinction event, sometimes informally called the Great Dying, was an extinction event that occurred approximately 251 million years ago (mya), forming the boundary between the Permian and Triassic geologic periods. ...

The construction of the shell-like structures of corals are aided by a symbiotic relationship with a class of algae, zooxanthellae. Typically a coral polyp will harbour particular species of algae, which will photosynthesise and thereby provide energy for the coral and aid in calcification,^[1] while living in a safe environment and using the carbon dioxide and nitrogenous waste produced by the polyp. Coral bleaching is a disruption of the balance between polyps and algae, and can lead to the breakdown and death of coral reefs. Extant Subclasses and Orders Alcyonaria    Alcyonacea    Helioporacea Zoantharia    Antipatharia    Corallimorpharia    Scleractinia    Zoanthidea [1][2]  See Anthozoa for details For other uses, see Coral (disambiguation). ... Common Clownfish (Amphiprion ocellaris) in their Magnificent Sea Anemone (Heteractis magnifica) home. ... Algae have conventionally been regarded as simple plants within the study of botany. ... Zooxanthellae are golden-brown intracellular endosymbionts of various marine animals and protozoa, especially anthozoans. ... The leaf is the primary site of photosynthesis in plants. ... Warm pink and yellow host coral organism due to stress. ...

Some echinoderms (starfish, sea urchins, sand dollars) and some polychaetes (annelid worms) also have hard exoskeletons. The now-extinct ostracoderms ("shell-skins") were a type of armoured marine fish which flourished in North America and Europe during the Ordovician, Silurian and Devonian geological periods. Classes Subphylum Homalozoa Gill & Caster, 1960 Class Homostelea Class Homoiostelea Class Stylophora Gill & Caster, 1960 Class Ctenocystoidea Robison & Sprinkle, 1969 Subphylum Crinozoa Class Eocrinoidea Jaekel, 1899 Class Paracrinoidea Regnéll, 1945 Class Cystoidea von Buch, 1846 Class Blastoidea Class Crinoidea Subphylum Asterozoa Class Ophiuroidea Class Asteroidea Subphylum Echinozoa Helicoplacoidea †  ?Arkarua... Orders Brisingida (100 species[1]) Forcipulatida (300 species[2]) Paxillosida (255 species[3]) Notomyotida (75 species[4]) Spinulosida (120 species[5]) Valvatida (695 species[6]) Velatida (200 species[7]) For other uses, see Starfish (disambiguation). ... Subclasses Euechinoidea Superorder Atelostomata Order Cassiduloida Order Spatangoida (heart urchins) Superorder Diadematacea Order Diadematoida Order Echinothurioida Order Pedinoida Superorder Echinacea Order Arbacioida Order Echinoida Order Phymosomatoida Order Salenioida Order Temnopleuroida Superorder Gnathostomata Order Clypeasteroida (sand dollars) Order Holectypoida Perischoechinoidea Order Cidaroida (pencil urchins) Sea urchins are small spiny sea creatures... Suborders Laganina Rotulina Scutellina Sand dollars are in the Echinoid (Echinoderms) class of marine animals. ... Orders Amphinomida Capitellida Chaetopterida Cirratulida Cossurida Ctenodrillidae Eunicida Flabelligerida Magelonida Myzostomida Nerillida Opheliida Orbiniida Orweniida Phyllodocida Pisionidae Polygordiida Protodrilida Psammodrilidae Sabellida Spionida Spintheridae Sternaspida Terebellida Tomopteris from plankton The Polychaeta or Polychaetes are a class of annelid worms, generally marine, with a pair of fleshy protrusions on each body segment... This article or section does not cite its references or sources. ... Artist impression of the Ordovician Sea. ... The Silurian is a major division of the geologic timescale that extends from the end of the Ordovician period, about 443. ... For the Celtic language, see Southwestern Brythonic language; for the residents of the English county, see Devon. ...

Arthropods

Many arthropods have sclerites, or hardened body parts, which form a stiff exoskeleton made up mostly of chitin. In crustaceans, especially those of the class Malacostraca (crabs, shrimp and lobsters, for instance), the plates of the exoskeleton may be fused to form a more or less rigid carapace. Subphyla and Classes Subphylum Trilobitomorpha Trilobita - trilobites (extinct) Subphylum Chelicerata Arachnida - spiders,scorpions, etc. ... A sclerite (Greek skleros meaning hard) is a hardened body part. ... Structure of the chitin molecule, showing two of the N-Acetylglucosamine units that repeat to form long chains in beta-1,4 linkage. ... For the Dutch band, see Crustacean (band). ... // Subclasses Eumalacostraca Hoplocarida Phyllocarida See text for orders. ... The term carapace refers to a dorsal section of an exoskeleton or shell, in a number of animal groups. ...

Chelonians

Sea turtles also form a carapace and plastron of bone and cartilage which is developed from their ribs. Genera Family Cheloniidae (Oppel, 1811) Caretta Chelonia Eretmochelys Lepidochelys Natator Family Dermochelyidae Dermochelys Family Protostegidae (extinct) Family Toxochelyidae (extinct) Family Thalassemyidae (extinct) Sea turtles (Superfamily Chelonioidea) are turtles found in all the worlds oceans except the Arctic Ocean. ... The term carapace refers to a dorsal section of an exoskeleton or shell, in a number of animal groups. ... The plastron is the nearly flat part of the shell structure of a tortoise, what we would call the belly, similar in composition to the carapace; with an external layer of horny material divided into plates called scutes and an underlying layer of interlocking bones. ... This article is about the skeletal organs. ... Cartilage is a type of dense connective tissue. ... The human rib cage. ...

Planktons and protists

Plant-like diatoms and animal-like radiolarians are two forms of plankton which form hard silicate shells. Orders Centrales Pennales Diatoms (Greek: (dia) = through + (temnein) = to cut, i. ... Classes Polycystinea Acantharea Sticholonchea Radiolarians (also radiolaria) are amoeboid protozoa that produce intricate mineral skeletons, typically with a central capsule dividing the cell into inner and outer portions, called endoplasm and ectoplasm. ... For the SpongeBob SquarePants character, see Sheldon J. Plankton. ... The chemical compound silicon dioxide, also known as silica, is the oxide of silicon, chemical formula SiO2. ...

Foraminifera and coccolithophore create shells called "tests" of calcium carbonate. Orders Allogromiida Carterinida Fusulinida - extinct Globigerinida Involutinida - extinct Lagenida Miliolida Robertinida Rotaliida Silicoloculinida Spirillinida Textulariida incertae sedis    Xenophyophorea    Reticulomyxa The Foraminifera, or forams for short, are a large group of amoeboid protists with reticulating pseudopods, fine strands that branch and merge to form a dynamic net. ... Coccolithophores are single-celled algae belonging to the haptophytes. ... A test is the shell of certain microbes, such as testate foraminifera and testate amoebae. ...

Shells as decorative items in human culture

Moche Shell. 200 A.D. Larco Museum Collection Lima, Peru.

Throughout the history of humanity, shells of many types and from many different kinds of animals have been popular as human adornments. They are often used whole and drilled so that they can be threaded like a bead, or cut into pieces of various shapes. Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... The Larco Museum (Spanish: ) is located in the Pueblo Libre District in Lima, Peru. ...

The uses have including all kinds of pendants, beads, buttons, brooches, rings, and hair combs among other uses. Beads Cloisonné beads Dichroic beads (10 mm) A bead is a small, decorative object that is pierced for threading or stringing. ... For other uses, see Button (disambiguation). ... Aquamarine, platinum and diamond brooch/pendant worn by Mrs. ... A finger ring is a band worn as type of ornamental jewellery around a finger; it is the most common current meaning of the word ring. ... A comb A comb for people with hair loss. ...

The Moche culture of ancient Peru worshipped animals and the sea and often depicted shells in their art.^[2] Native American used shells for wampum and hair pipes.^[3] The Moche civilization (alternately, the Mochica culture, Early Chimu, Pre-Chimu, Proto-Chimu, etc. ... Native Americans redirects here. ... Wampum is a string of white shell beads fashioned from the North Atlantic channeled whelk (Busycotypus canaliculatus) shell, and is traditionally used by Indigenous Americans, First Nations peoples, Native Americans, hobbyists, business people, and traders, who regarded it as a sacred or trade representative of the value of the artist... A Hair Pipe is a term for a long narrow bead, more than 1. ...

Small pieces of colored and iridescent shell have been used to create mosaics and inlays which have been used to decorate larger items such as boxes and furniture. Large numbers of whole seashells, arranged to form patterns, have been used to decorate man-made grottos. This article is about a decorative art. ... Inlay: Decorative technique of inserting pieces of coloured materials to form patterns or pictures. ... This article or section does not adequately cite its references or sources. ...

See also

• The Bailey-Matthews Shell Museum
• Seashell surface, a mathematical construct

The Bailey-Matthews Shell Museum open to the public in 1995, the Museum has operated as an information and reference center for national and international scientists, students, and shell enthusiasts who are interested in the marine, terrestrial, and land mollusks of the Gulf of Mexico and Florida. ... Seashell surface with parametrization on left In mathematics, a seashell surface is a surface made by a circle which spirals up the z-axis while decreasing its own radius and distance from the z-axis. ...

References

1. ^ Madl, P. and Yip, M. (2000). Field Excursion to Milne Bay Province - Papua New Guinea. Retrieved on 2006-03-31.
2. ^ Berrin, Katherine & Larco Museum. The Spirit of Ancient Peru:Treasures from the Museo Arqueológico Rafael Larco Herrera. New York: Thames and Hudson, 1997.
3. ^ Shell Hair Pipes used in Indian Adornment

Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 90th day of the year (91st in leap years) in the Gregorian calendar. ... The Larco Museum (Spanish: ) is located in the Pueblo Libre District in Lima, Peru. ... Thames & Hudson (also Thames and Hudson and sometimes T&H for brevity) are a publisher, especially of art and illustrated books, founded in 1949 by Walter and Eva Neurath. ...

External links

Look up seashell in
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• 110 Photos of various seashells
• Conchologists of America