Several species of lancelets, or amphioxi, small, fishlike, filter-feeding animals found in shallow water.

A lancelet has a long body, pointed at both ends, with a large notochord that extends almost from tip to tip and is present throughout its life.

At one end is a mouth surrounded by prominent bristles and leading into a pharynx where there are gill slits, an endostyle similar to that of a sea squirt, and an atrium surrounding the pharynx.