Terminology Description
Terminology Description
Beak the first formed part of a valve, usually above the hinge.
Bifid split in two (as in the tooth in the hinge).
Byssus clump of horny threads spun by the foot and attached to the hard bottom.
Cardinal tooth hinge tooth situated near the umbo.
Concentric sculpturing running parallel to the growth margin of the valves.
Escutcheon a smooth, long surface on the upper margin of the valve behind the horny ligament.
Gape opening or gap at either end of the closed valves.
Hinge top interlocking margin of the valves, usually with teeth.
Lateral tooth hinge tooth situated before or behind the cardinal teeth and at greater distance from the umbo.
Ligament an external or internal horny band, usually behind the beaks, holding the valves together or ajar.
Lunule an arrow-shaped or heart-shaped impression on the valves just in front of the beaks.
Pallial sinus an embayment or U-shaped curve in the pallial line.
Periostracum an outer layer of thin or thick chitinous material covering the outer shell.
Radial sculpture or colour rays running from the beaks to the lower margins of the valves, crossing the concentric sculpturing one of the main shelly halves of a bivalve.
Siphon slits allowing the enterance of water (inhalant, ventral siphon) or its exit (exhalant, dorsal siphon).
Valve one of the main shelly halves of a bivalve