This Subphylum is mostly made up of lancelets. Collectively, they are known as cephalochordates. Lancelets are slender, laterally compressed, and eel-like in appearance and behavior. They are benthic animals that burrow in coarse, shelly, current-swept sands, usually in shallow near-shore areas. Their heads project above the sand into the water where they filter suspended food particles. Lancelets ingest large amounts of particles from which they extract organic material while eliminating water through gill slits.