Animals with spinal cords. This includes all vertebrates (animals with backbones) and a few other animals with spinal cords.
                                                            
                                                     
                        
                                                
                        
                        
                            Animals that possess a rod of flexible tissue (notochord); includes vertebrates (fish, amphibians, reptiles, birds and mammals).
                                                            
                                                     
                        
                                                
                        
                        
                            a biological division including chiefly the vertebrates, but embracing also those animals that have a notochord -- an elastic rod dividing the dorsal from the ventral regions.
                                                            
                                                     
                        
                                                
                                                     
                        
                        
                            animals with rods along their backs, including reptiles, amphibians, birds, and mammals.
                                                            
                                                     
                        
                                                
                        
                        
                            Animals possessing a notochord at least at some stage of development : They include all vertebrates and a few lower forms. ~ See Also: Notochord.
                                                            
                                                     
                        
                                                
                        
                        
                            a group of animals (phylum Chordata) which have, at some time in their development, a notochord, gill slits and a dorsal nerve cord. Chordates include vertebrates and tunicates.