These animals have a true vertebral column and internal skeleton, allowing a completely different distribution of muscle attachment
points to be used for movement.
Vertebrates are bilaterally symmetrical, triploblastic, coelomic and segmented, with complex differentiation of body tissues and organs. All chordates possess the following features:
(i) have a notochord
(ii) have a dorsal nerve cord
(iii) are triploblastic
(iv) have paired gill pouches
(v) are coelomate.
Vertebrates are grouped into six classes.
