[The development of stria vascularis in the guinea pig fetus]

In the 25 day old guinea pig fetus the lateral wall of the ductus cochlearis is lined with a cylindrical epithelium consisting of a single layer of columnar cells, which opens onto the endolymphatic space. It is clearly separated from the adjacent structures by a basal membrane. This connective tissue contains numerous cells with fibroblastic features, more abundant and larger, the nearer they are to the basal membrane. In the segment of the marginal cells adjoining the endolymphatic cleft sometimes shows up a basal body, suggesting the existence of a kinocilium. The cellular surface is covered with small microvilli. In the 50 day old guinea pig fetus, the development of the stria vascularis is already similar to that of the adult animal.