We propose to characterize first-order afferent responses to physiological stimuli from the semicircular canals of the guitarfish, and to correlate them with the anatomical regions of innervation of individual receptors. The characterization will be done with the aid of on-line computer techniques; and the anatomical investigations will be done by microdissection and neuro-histological techniques. A second project is proposed to investigate mechanisms of mechano-neural transduction in the semicircular canal by electrical polarization methods in view of recent models of the transduction process. A third projjct is to characterize the gravitational and vbrational responses from the utricle and sacule by the use of on-line systems analysis and neurohistological techniques. Bibliographic references: O'Leary, D.P. and V. Honrubia, 1975. On-line identification of sensory systems using pseudorandom binary noise perturbations. Biophys. J., 15: 505-532. O'Leary, D.P. and C. Wall III, 1975. Response properties of spontaneously inactive first-order afferents innervating the isolated guitarfish semicircular canal. Association for Research in Otolaryngology, Presented in Dallas, Sept. 1975.