Definition
Solenogastres are a class of small, worm-like mollusks lacking shells. They are also known as Aplacophora, meaning "without a shell." They live on the seafloor, feeding on microorganisms and cnidarians (like corals and anemones). They have a distinctive groove on their underside called a pedal groove, used for locomotion. Their bodies are covered in scales or spicules. They are closely related to chitons, though they look very different.