The ultrastructure of the eyespot region of Chlamydomonas eugametos was studied with the freeze-etch technique. In the region of the eyespot the outer chloroplast membrane, when fractured medially, showed the presence of bulgings which appeared as either depressions or bumps depending on the cleavage plane. These deformations of the outer chloroplast membrane produced by the granules of the eyespot are about 80 mμ in diameter and form ordered arrays of 800 or more particles.