Which animal retains the notochord throughout life?

Chorda persists throughout life in all chordates. For example – lancelet. Chorda is an analogue of the ridge in animals. Many fish do not have a ridge, but have a chord, since a chord is quite enough for them. Man also has a chord. But we have it at an early stage of intrauterine development. Then, in the process of development, it disappears and a person is born with a ridge, not a chord. Many mammals have this feature. There are three types of chordates: cranial, larval-chordate, and cranial.