During the next grant period we will continue to complete our analysis of the maturation of sensory receptors in laryngeal mucosa. As noted in previous progress reports, we have been especially concerned with the earlier stages of differentiation in that a precocious development of nerves is encountered overlying the arytenoids and we have not traced this back to its earliest appearance during embryonic development. The early maturation of chemosensory corpuscles will also be evaluated in the younger specimens to be harvested during the next grant period. We had originally proposed that maturation of sensory receptors during the last trimester of gestation would prove the most fruitfull and the current findings have changed our priorities to an earlier onset of differentiation of major sensory receptors. We would hope that during this next project period some suitable human autopsies might be available to provide additional correlation in terms of sequence of maturation of sensory receptors in the upper airway.