Cephalochordata

What Is Phylum Cephalochordata? Phylum Cephalochordata is a small group of marine chordates that retain the main chordate characteristics throughout their adult life. They are commonly known as lancelets or amphioxus. Cephalochordates have a small, elongated, fish-like body and usually live partially buried in shallow marine sediments. Their body contains a notochord, dorsal hollow nerve