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More About Molluscs ...
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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. These range from tiny snails and clams to the octopus and squid (which are considered the most intelligent invertebrates). The giant squid is the largest invertebrate, and, except for their larvae and some recently captured juveniles, has never been observed alive, although the Colossal Squid is likely to be even larger.
Mollusks are triploblastic protostomes. The principal body cavity is a blood-filled hemocoel, with an actual coelom present but reduced to vestiges around the hearts, gonads, and metanephridia (kidney-like organs). The body is divided into a head, often with eyes or tentacles, a muscular foot and a visceral mass housing the organs. Covering the body is a thick sheet called the mantle, which in most forms secretes a calcareous shell.
Mollusks have a mantle, which is a shell-like outer cover, and a muscular foot that is used for motion. Many mollusks have their mantle produce a calcium carbonate external shell and their gill extracts oxygen from the water and disposes waste. All species of the phylum Mollusca have a complete digestive tract that starts from the mouth to the anus. Many have a radula, mostly composed of chitin, in the mouth, which allows then to scrape food from the surface by sliding back and forth. Mollusks also have a coelom, made from cell masses, where all organs are suspended. Unlike Coelomates, mollusks lack body segmentation.
Development passes through one or two trocophore stages, one of which (the veliger) is unique to the group. These suggest a close relationship between the mollusks and various other protostomes, notably the Annelids.
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Source: Wikipedia Read more about Molluscs
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INFO LINKS
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Tridacnid Clam
Safari Splash
Brief descriptions of various Tridacnid Clams and pictures Read More
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Partula Snail
The Wild Ones
Brief article about Partula Snail Read More
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Atlantic Bay Scallop
The Assateague Naturalist
Brief description and pictures Read More
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Channeled Whelk
The Assateague Naturalist
Brief description and pictures Read More
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Eastern Oyster
The Assateague Naturalist
Brief description and pictures Read More
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Atlantic Slipper Shell
The Assateague Naturalist
Brief description and pictures Read More
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Clam
The Assateague Naturalist
Bivalve Anatomy Read More
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Bivalve
Natural History Museum - Archerd Shell Collection
Image gallery of Bivalves Read More
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Gastropod
Natural History Museum - Archerd Shell Collection
Image gallery of Gastropods Read More
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Chiton
Natural History Museum - Archerd Shell Collection
Image gallery of Chitons Read More
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Tusk Shell
Natural History Museum - Archerd Shell Collection
Image gallery of Tusk Shells Read More
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Cephalopod
Natural History Museum - Archerd Shell Collection
Image gallery of Cephalopods Read More
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Bivalve Molluscs
Japan Sea Coastal Zone And Peter The Great Bay
Image gallery of Bivalve Molluscss, with brief articles for eac species Read More
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Bivalve Molluscs
A Beginner's Introduction to Molluscs
Kid friendly article about bivalves, has picture of a 740 pound clam! Read More
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Chiton
A Beginner's Introduction to Molluscs
Kid friendly article about chitons Read More
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Oyster
Western Australia Dept. of Fisheries
Article about how an oyster makes a pearl; information about oyster farming Read More
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Giant Clam
Aquatia Bataria
Brief description and picture. "The largest clam species may reach a length of 4 feet". Read More
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Dwarf Wedgemussel
National Wildlife Federation
Categorized information about Dwarf Wedgemussel Read More
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Ouachita Rock Pocketbook Mussel
National Wildlife Federation
Categorized information about Ouachita Rock Pocketbook Mussel Read More
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Powelliphanta Land Snail
Department of Conservation, New Zealand
Fact Sheet Read More
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Wheke Octopus
Department of Conservation, New Zealand
Fact Sheet Read More
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Octopus
Tralfaz World
Octopus cam, picture gallery, and more Read More
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