For more information see
The moon snails are
heavy snail with the last whorl - the body whorl, greatly enlarged. There are about five other whorls that form
a low but distinct spire. When the body expanded, it is much larger then the shell and it covers the shell. Light
tan to yellow is about the color of the shell. A horny brown operculum covers the opening.
The website below contains more information and photos:
http://lanecc.edu/science/zonation/moonsnai.htm