ZoologyThey have a bilateral body plan: a head and tail end, a front and back side.
They are are deuterostomia, meaning that the anus forms before the mouth.
They are coelomates, having a fluid-filled body cavity called a coelom with a complete lining called peritoneum derived from mesoderm.
They have a notochord, developing into a spinal cord, the main communications trunk of the nervous system.
They have pharyngeal slits; in fish, the slits are modified to form gills.
They have a post-anal muscular tail.
They have an endostyle, a groove in the ventral wall of the pharynx; it filters food, produces mucus, transports food to the esophagus; it also stores iodine in the thyroid gland.