MeSH definition : 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.;
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.