June 12, 2008


A shell is a part of a sea creature known as mollusk. Mollusks are wormlike creatures and exist in the ocean, fresh water and also on land. The main characteristic of mollusks is that they dont have internal skeleton. Their shell serves as an exo-skeleton and protects them from the outside world. The shells are primarily composed of calcium carbonate, which is secreted by the outer surface of the mantle of the shell and are loosely attached to the animal body.
The food consumed by mollusk causes pigments to be produced within the mantle and based on this pigment secretion the outer shell's color and shapes are formed. If the pigment secretion is continuous, spiral or radial lines are formed. If the pigment secretion is periodic, then spots appear on the shell. When the mollusk dies, its shell is the one part that typically remains intact. Seashells are very often found in beach drift, which is deposited along strandlines on beaches.

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