Clayton Persak, age 11, of Wilmington, Del., for his question:

HOW LARGE WILL A COWRIE GROW?

A cowrie is a sea snail with a shiny, colorful shell. Sometimes the name is spelled cowry. It lives in the shallow water of most warm seas and may range in size from about a half an inch to six inches in length.

The top of the cowrie looks like a colorful egg and the underside has a long, narrow opening bordered by what looks like many small teeth.

There are more than 150 different kinds of cowries. Some kinds are extremely rare and are worth hundreds of dollars to collectors. Collectors all over the world are always on the look out for new cowries.

Cowries were once used as money in China, India and Africa.

One type of cowrie was worn as a badge of office by the chieftains of various villages in the Fiji Islands.