Timothy Bell, age 11, of Inverness, Miss. 

Does an oyster create its own shell?

An oyster is usually served on a little rough shell,, neat as a turkey on a platter, The turkey# however, did nothing to help make his platter, The little oyster's half‑shell dish is his own creation. Actually, it is one half of his house, The other half is a somewhat smaller shell and the two halves fit together with the living oyster inside. It takes about four years for the oyster to grow big enough for the market and all that time is spent at the bottom of some shallow sea,

The oyster is a member of the humble Mollusca phylum cousin to the clams and distantly related to the slow‑poke snail. His soft little body has no bones and no teetho no‑head and no limbs, He has a few simple nerves, however, the simplest kind of heart and gills for extracting oxygen from the water,

Most important, he has a sturdy muscle which passes through his body with one end fixed firmly on the narrow end of each shell, This muscle joins the two shells together and acts like a hinge, The oyster uses, it to open the two shells perhaps half an inch and let in the sea water carrying oxygen and scraps of food, He can also use this hinge muscle to shut his two shells together and hold them tight.

The baby oyster spends the first two weeks of his life swimming freely through the water, He hatches from a microscopic egg and the two shells or valves are there from the very beginning, At first they look like a pair of miniature fish scales tightly cupped together. When the young oyster settles on some solid surface below the water he becomes a stay ­at‑home for the rest of his life and the shells begin to grow and harden,

The soft oyster body is enfolded in flabby flaps of skin called the  mantles. The crusty shells are made 'from these soft layers of skin,

Among other things, the body of the oyster extracts limy calcium material from the sea water. Special cells in the mantle use this substance and ooze it out in layers of hard, limy shell.

The outside wall of each shell is as rough and as grubby as the bark of a gnarled old oak tree. The inside wall is delicately tinted and as satin smooth as a lustrous pearl. In fact, it is made of nacre# the very same material from which precious pearls are made, Actually the shell is made from a sandwich of three different layers. The center layer is made of calcium cells arranged like miniature prisms,

All these different layers are made by the soft mantles which enfold the oyster, one above and one below his body. The crusty outer layers and the middle layers of the shells are secreted by cells at the edges of the mantles. The glossy inner layer is secreted from all the surface cells of the mantles. For the oyster, the job of house building is never done. The shells grow with him, getting bigger as he needs more room. The inside walls are forever being relined with smooth glossy coats to protect the oyster's soft body from scratches and bruises,