Gastropods are snails and slugs. They have a very limited sensory capacity. They have a mantle which secretes the shell. A gastropod's foot is on its underside which it uses for locomotion. A gastropod also has a radula, a coiled, straplike tongue studded with teeth, which it uses to scrape surfaces.
A Pleisia is a sea snail without a shell.

*Pictures to be added, end of summer 1999!*