Displaced ganglion cells in the chick retina.

New morphological and cytological data on the displaced ganglion cells (DGCs) in the chick retina are presented. Analysis of the topographic distribution, cellular number, dendritic field, perikaryon size and ultrastructural characteristics are included. The DGCs were found predominantly in the peripheral retina. The sizes of the DGCs, 18-42 microns, observed either by Normarsky's interferential contrast or by silver impregnation techniques, spanned the size range of the other retinal neurons. The results support the hypothesis that DGCs, in the chick retina, may constitute a specific morphofunctional system, and therefore they might not be considered as neurons that fail to attain the normal location of ganglion cells during the developmental process of migration.