A portion of the animal phylum Chordata comprised of the subphyla CEPHALOCHORDATA; UROCHORDATA, and HYPEROTRETI, but not including the Vertebrata (VERTEBRATES). It includes nonvertebrate animals having a NOTOCHORD during some developmental stage.
Subtype terms (3)
More specific conditions that are subtypes of Chordata, Nonvertebrate in the MeSH hierarchy.