In cell cultures of the retina from 10 days old chicken embryo photoreceptors, bipolar neurons, synaptic contacts, and supporting cells of Müller were demonstrated by scanning electron microscopy. It was found that the longer the cells survive in culture media they form constantly growing cell aggregates. After 12 days in vitro large multilayered cell complexes covered by an epithelioid cell layer had developed. Merely at the border of such aggregates typical retinal cells could be observed. The occurrence of a dense epithelioid cell layer covering the aggregate of neuronal cells is interpreted as a general adaptational reaction of the cells to the long lasting survival under in vitro conditions.