[Receptor surface of Corti's organ in guinea pig embryos]

Using scanning electron microscope, studies have been made of the structure of the receptive surface of the organ of Corti in 48- and 57-day old embryos of the guinea pig. It was found that some structural modifications take place in this period: the size and the number of microvilli in the supporting cells decrease, the width of the organ of Corti increases, the number of ball-like cytoplasmic protrusions from the cellular surface decreases, the number of kinocilia in the receptor cells is reduced. These processes are associated presumably with the development of Nuel's space, Corti's tunnel, the origin of flexible connection between the tectorial membrane and the receptive surface, as well as with maturation of the ionic composition of the inner ear fluid.