amphioxus, plural amphioxi, or amphioxuses, also called lancelet, any of certain members of the invertebrate subphylum Cephalochordata of the phylum Chordata. Amphioxi are small marine animals found widely in the coastal waters of the warmer parts of the world and less commonly in temperate waters.

Where are Lancelets found?

Ecology and habitats. Lancelets are distributed throughout the world along tropical and temperate coasts. They inhabit soft bottoms ranging from sand to coarse shelly sand or gravel in shallow coastal water.

Is amphioxus is a fish?

The lancelet Branchiostoma lanceolatum, or amphioxus as it is commonly called, is a small, translucent animal some 4–6 cm in length. Although amphioxus resembles a fish, it has a much simpler organisation (Fig. 9.1). ... As its body shape suggests, the animal is able to swim effectively.