Six- and 13-day chicken embryo retinas contain 10 and 320 fmol per mg of protein of specific binding sites for 3-[3H]quinuclidinyl benzilate, a ligand of muscarinic acetylcholine receptors. Most of the receptors of 13-day embryo retina were found, by autoradiography, to be localized in two sharp bands within the inner synaptic layer of the retina. In the adult, the receptors were found almost exclusively in three bands in the inner synaptic layer of the retina. A possible mechanism for generating sets of stratified or columnar neurons and relating one set to another is proposed.