Chordates are characterised by a rod-like notochord and a hollow nerve cord on the dorsal side of the gut, and pharynx being perforated with gill slits for respiration. Vertebrates have a vertebral column that replaces the notochord, cephalization of the nervous system, a ventral heart, a post-anal tail and division of the coelom into chambers.
The following chapters appear in this section. Click on the title to open.