Kathy Simos, age 12, of Milwaukee;, Wis., for her question:

Is a snail born with a shell?

The snail begins life as an egg, left to hatch in the: silvery trail behind its parent. The egg; hatches out into a baby snail, a tiny fellow almost as clear as glass. Under a magnifying glass you can see the tiny infant's little heart slowly beating. You can also see that the wee baby has a shell, a little glassy hump on his back.

As soon as he hatches, the baby snail sets about eating his first meal. This is the remains of his egg. The parent snail has left a store of lime in the egg food and this limy: enters the body of the little snail and turns his body opaque. So he soon loses his glassy look.

The snail secretes material from his body which hardens into shell. He adds spiral by spiral as he grows„ The average garden snail is fully grown when he has grown five spirals to his shell. By then he is about two years old and has produced many baby snails of his own.