Subsurface membranes in paired cone photoreceptor inner segments of adult and neonatal Lebistes retinae

Rectangular membranous sheets, consisting of three components, subsurface and parallel to the apposing plasma membranes, are found in the inner segments of each of the two members of the Lebistes retinal paired cone photoreceptors. The subsurface membranes are without fenestrations and lack continuity with the closely applied plasma membranes. As the subsurface membranes are coextensive with the area of closely apposed plasma membranes, they are believed to represent a layer of insulation or a specialized cell-to-cell contact zone.