Class Larvacea, also known as Appendicularians, are small, marine filter-feeding creatures that belong to the phylum Chordata. These planktonic animals are known for their translucent bodies and the presence of a protective outer tunic. Some of the synonyms for Class Larvacea include planktonic tunicates, sea squirts, and filter-feeding tunicates. They are also sometimes confused with salps, which belong to a different class of tunicates. These delicate organisms play an important role in marine ecosystems, as they help to cycle nutrients and are preyed upon by a variety of larger organisms, including fish and whales.