Etymology
The taxonomic term Bivalvia was first used by Linnaeus in the 10th edition of his Systema Naturae in 1758 to refer to molluscs having shells composed of two valves. More recently, the class was known as Pelecypoda, meaning "axe-foot" (based on the shape of the foot of the animal when extended). Other names used for this class include Lamellibranchia (based on the plate-like gill elements, the ctenidium) and Acephala (bbecause, unlike other molluscs, these animals have no head).
The name "bivalve" is derived from the Latin bis, meaning "two", and valvae, meaning "leaves of a door". Not all animals with shells with two hinged parts are classified under Bivalvia; other animals with paired valves include certain gastropods (small sea snails in the family Juliidae), members of the phylum Brachiopoda and the minute crustaceans known as ostracods and conchostrachans.
Read more about this topic: Bivalvia
Famous quotes containing the word etymology:
“Semantically, taste is rich and confusing, its etymology as odd and interesting as that of “style.” But while style—deriving from the stylus or pointed rod which Roman scribes used to make marks on wax tablets—suggests activity, taste is more passive.... Etymologically, the word we use derives from the Old French, meaning touch or feel, a sense that is preserved in the current Italian word for a keyboard, tastiera.”
—Stephen Bayley, British historian, art critic. “Taste: The Story of an Idea,” Taste: The Secret Meaning of Things, Random House (1991)
“The universal principle of etymology in all languages: words are carried over from bodies and from the properties of bodies to express the things of the mind and spirit. The order of ideas must follow the order of things.”
—Giambattista Vico (1688–1744)