Although they resemble eel-like fish, the humble lancelets are in fact a primitive group that are part way between those animals that do not have a backbone (invertebrates) and those that do (vertebrates).
Lancelets are small marine animals that spend much time burrowing in the seabed, although they can swim.Their narrow, fishlike body is pointed at both ends. They have a narrow dorsal (back) fin and a small, rounded tail fin.The head of a lancelet is small and has no eyes. There is a well-developed nerve cord that connects with a simple brain. The brain is not enclosed in a braincase.The mouth has no jaws or teeth, and
