Tripsin-HCl method (Uehara) was applied to the lateral cochlear wall of guinea pig for the scanning electron microscopical study of the innerstructure. Capillaries in the spiral prominence is intimately covered by the thick cytoplasmic processes of pericytes mosaickened the entire surface of the vessels. This feature is specific to the vessel and undoubtedly different from the capillaries in the stria vascularis and spiral ligament. These vessels are covered by the fine mesh-like architecture of cytoplasmic processes extended from the longitudinally oriented pericytes. The peculiar feature of external sulcus cells are also observed which has been reported by J. A. Duvall with three dimensional reconstruction technique at electron microscopical level.
It is suspected that these structures may play some role in resorption and secretion of the endolymph and could support the radial flow theory.
