Visceroconcha

mollusk supraclass

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July 14, 2026

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The term "Visceroconcha" refers to a supraclass within the phylum Mollusca. This group is characterized by a free head, distinct from the mantle and shell, and includes subclasses such as the gastropods (snails) and cephalopods (like squid and octopuses). Unlike bivalves, which have a shell divided into two valves and lack a distinct head, Visceroconcha possess a posterior mantle cavity and lateral nerve cords. This classification is based on evolutionary and anatomical distinctions within the diverse phylum Mollusca.123

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mollusk
Evolution and paleontology
…and shell in the supraclass Visceroconcha, including the gastropods and the cephalopods; both share a posterior mantle cavity, lateral (or pleural) nerve cords medial to the dorsoventral musculature, and an antagonistic muscle system (see above Internal features: Muscles and tissues). The relation of the fossil order Bellerophontacea is controversial.
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…and shell in the supraclass Visceroconcha, including the gastropods and the cephalopods; both share a posterior mantle cavity, lateral (or pleural) nerve cords medial to the dorsoventral musculature, and an antagonistic muscle system (see above Internal features: Muscles and tissues). The relation of the fossil order Bellerophontacea is controversial.
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