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Cephalochordata (Lancelets)

  1. Richard PS Jefferies

Published Online: 19 APR 2001

DOI: 10.1038/npg.els.0001530



How to Cite

Jefferies, R. P. 2001. Cephalochordata (Lancelets). eLS. .

Author Information

  1. The Natural History Museum, London, UK

Publication History

  1. Published Online: 19 APR 2001


The Cephalochordata constitute one of the three traditionally recognized subphyla of the Chordata, the other two being the Tunicata (Urochordata) and the Craniata (including the Vertebrata). They are also known as Acraniata or lancelets. There are only two extant genera, Branchiostoma (amphioxus) and Epigonichthys (Asymmetron).


  • chordata;
  • left–right asymmetry;
  • calcichordates;
  • echinodermata