LARVACEAN

also called Appendicularian, any member of the class Larvacea, of the subphylum Urochordata, or Tunicata, belonging to the phylum Chordata. Reaching lengths of 5 mm (0.2 inches), larvaceans are transparent, larva-like organisms that live in the open sea. The U-shaped body consists of a trunk and tail. The body secretes a structure larger than itself, within which the animal moves freely.