inner ear

The auditory organ lying in the otic capsule, constisting of the semicircular canals, ampullae, utriculus, sacculus, lagena, sinus endolymphaticus and ductus endolymphaticus, Filled with and surrounded by perilymph (or seawater in forms with an endolymphatic duct), containing otoliths (sagitta, astericus and lapillus in teleostomes). Functions as a gravity receptor, acceleration detector and muscle tone regulator. Innervated by cranial nerve VIII.