Lamellibranchiata

Definitions

  • Webster's Revised Unabridged Dictionary
    • n. pl Lamellibranchiata (Zoöl) An earlier name for the class of Mollusca including all those that have bivalve shells, as the clams, oysters, mussels, etc., now called Pelecypoda or Bivalvia .☞ They usually have two (rarely but one) flat, lamelliform gills on each side of the body. They have an imperfectly developed head, concealed within the shell, whence they are called Acephala . Called also Conchifera, and Pelecypoda. See Bivalve.
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Century Dictionary and Cyclopedia
    • lamellibranchiata A group of mollusks without distinct head or cephalic eyes, with the branchiæ on each side of the body and generally expanded in a plate-like or lamelliform manner, and with a shell of two lateral valves completely or partly inclosing the body. The valves of the shell are connected and close over the back of the animal by a hinge; they are also generally united by one or two muscles, called adductors, which penetrate the body-mass. Opening of the shell is effected by an elastic ligament in or about the hinge. The shell is secreted by a prolongation of the integument called the mantle or pallium, which laps round the body, its halves being either free or united so as to leave only three apertures for the inlet and outlet of water tor respiration, and for the protrusion of a fleshy organ called the foot, when it is present. The muscular edge of the mantle leaves on each valve an impression called the pallial line. Respiration is generally effected by lamellated gills (whence the name), usually occupying a large part of the interior of the shell on each side. The mouth is a simple jawless fissure, furnished with one or two pairs of soft palpi, the food being conveyed to it by cilia on the gills, The heart has a single ventricle pierced by the intestine, and there are three double nerve-centers. The group was originally designated by the author of the name (De Blainville, 1814) as art older, but has generally been adopted as a class of Mollusca, containing all the true or ordinary bivalve mollusks, of which oysters, clams, etc., are familiar examples. Synonyms of the whole group are Acephala, Bivalvia, Conchifera, Cormopoda, and Pelecypoda.
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Chambers's Twentieth Century Dictionary
    • n.pl Lamellibranchiata a class of shell-fishes or molluscs in which the shell consists of two limy plates, lying one on each side of the body
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Etymology

Webster's Revised Unabridged Dictionary
NL. See lamella, and Branchia Branchiate
Chambers's Twentieth Century Dictionary
L.

Usage

In literature:

In the Lamellibranchiata, or bivalve shells, hermaphroditism is not rare.
"The Descent of Man and Selection in Relation to Sex, Vol. I (1st edition)" by Charles Darwin
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