Notochord is persistent throughout life in
Chondrichthyes and Osteichthyes
Urochordata and cephalochordata
Cephalochordata and Chondrichthyes
Cephalochordata and Hemichordata
Notochord is persistent throughout life in Cephalochordata, Cyclostomata and Chondrichthyes.
In urochordates, notochord is present only in the larval tail.