I. Introduction.- II. Material and Methods.- III. Form and Interconnections of the Vestibular Ducts and Sacs.- IV. The Vestibular Nerve and Its Ramifications.- V. Structure of the Vestibular Sensory Epithelia.- VI. Morphological Polarization of the Sensory Cells.- VII. Innervation of the Vestibular Sensory Epithelia.- VIII. Form and Structure of the Statoconial Membranes and the Cupulae.- IX. General Discussion.- X. Summary.- Acknowledgement.- References.