The fishlike amphioxus has a structure called a notochord which in humans develops into this column
Structure In the human vertebral column there are normally thirty-
three ..... as amphioxi (singular, amphioxus )  comprise some 32 species of fish
-like... [DOC] [TLE] BBC - Earth - Why we have a spine, when over 90% of animals don't [PAR] Aug 15, 2016 ...