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;a. Mantle: The mantle is an organ covering the soft parts of a mollusk. It secrets calcium carbonate to create the shell.
;b. Foot: The foot is the largest visible portion of a mollusk other than the shell. It is the soft part that protrudes from the shell and touches the surface of whatever the mollusk is crawling on.
;c. Teeth: The ''"teeth"'' of a mollosk are called ''radula'' by scientists. They are more like a jagged tongue than they are like teeth (see the diagram on the right). Mollusks use them to chew food and to scrape algae from rocks.
;d. Ribs: Ribs are any raised ridges on the surface of a shell.
;e. Valve: A valve is half the shell of a mollusk with a two-part shell. The two valves are joined by a hinge. These mollusks are called ''bivalves'', and include clams, oysters, and mussels.
;f. Dorsal border: The dorsal border is the edge of a bivalve's shell where the hinge is located.
;g. Apex: The apex is the tip or point of the shell. It is not labeled in our diagram, though it is clearly visible (lower right).
;h. Operculum: The operculum is a hard structure situated at the end of the foot, and is used to seal off the entry to the shell. You can think of it as a combination shoe/door.
;i. Canal: Many marine gastropods are burrowers, and have soft siphons or tubes that extend from the mantle. Sometimes the shell has a siphonal canal to accommodate this structure. These siphons act as snorkels, enabling the animal to continue to draw in a water current containing oxygen and food into their bodies. The siphons are also used to "taste" the water, in order to detect prey from a distance.
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Translations:Adventist Youth Honors Answer Book/Nature/Shells/3/en - Revision history

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