Chordates are coelomate animals that possess: 1  a supporting rod or notochord; 2  a single hollow dorsal nerve cord; â 3 metameric segmentationâ: division of the body muscles into similar units, known as segments, that are arranged serially one behind the other;hey differ from the invertebrate chordates in possessing 1  : an internal skeleton, including a vertebral column which encloses the nerve cord; 2  a brain enclosed in a skull; 3  a pumping heart and efficient blood circulation.