Phylum Mollusca Phylum Mollusca Molluscs are bilaterally symmetrical eumetazoans.
Development is protostomous.
An important characteristic of most molluscs is the head-foot region. Adjacent to the head is a large, muscular foot formed from the ventral body wall. Used primarily in locomotion, the surface of the foot is sometimes ciliated and and laden with numerous mucous glands. Another characteristic of most molluscs is the mantle. This sheath of tissue is formed from the dorsal body wall.