The inner ear or labyrinth has two parts, outer bony labyrinth and the inner membranous labyrinth. The space between the two is filled with perilymph. The coiled part of the labyrinth is called cochlea. It has two membranes: Reissner's membrane and basilar membrane. They divide the cochlea into upper scala vestibuli, middle scala media and lower scala tympani. Out of these, scala media has endolymph, while scala vestibuli and scala tympani have perilymph.