Paul Robert, age 12, of Church Rock, N.M., for his question:

WHAT IS THE REGAL MUREX?

The regal murex is a spectacularly beautiful sea shell that can be found on the Pacific Coast from Mexico to Panama. It is classified as a univalve shell.

The regal murex is in a large family group. Scientists have identified more than 60,000 different species of univalve shells. They range in size from a conch found in Florida that is about two feet long to the Barlia snail shell that can hardly be seen—a row of 30 measures about one inch. The regal murex falls in between: it is about four inches long.

The regal murex has an opening at one end. The creature who lived in the shell used the case to keep out such enemies as fish and crabs.