, pl. tapeta [TA] (1) In general, any membranous layer or covering. (2) [TA], neuroanatomy a thin sheet of fibers in the lateral wall of the temporal and occipital horns of the lateral ventricle, continuous with the corpus callosum. SYN: Fielding membrane, membrana versicolor. (3) A dense layer in the choroidea of the eye of many mammalian species, including the cat and dog but not humans, which forms a discrete or diffuse area of reflective cells, rodlets, and fibers; its strong light-reflecting properties cause the metallic hue and light-glow of such eyes in the dark. [L. tapeta, a carpet]