They lack a notochord, a nerve cord and tail. They possess only pharyngeal slits. Larval tunicates are free swimmers and possess all four chordate characteristics. Larva attach by the head on a surface and undergo metamorphosis to adult form. Subphylum Cephalochordata Animals in the subphylum Cephalochordata are known as lancelets due to their bladelike shape.
Chordate characteristics are prominent and persist in the adult.
Postanal tail Cephalochordates are marine filter feeders. They burrow tail first into the sand with only the anterior exposed. Water is drawn into mouth by ciliary action and food is trapped on a mucous net secreted across the pharyngeal slits. Water exits through the slits and trapped food passes down the digestive tube. Cephalochordates are feeble swimmers with fishlike motions.