Morphology of horizontal cells in the frog retina.

Two types of horizontal cells, H1 and H2, were classified using the Golgi technique on flat mounts of the retina of the frog. Cell type H1 possesses rather short, thick dendrites; the diameter of its dendritic field ranges from 40-90 micrometers. H2-cell displays long and thin dendrites; the diameter of its dendritic field is 70-160 micrometers. H1-cells possess an axon running horizontally within the outer plexiform layer. The axon terminals are slight swellings emitting fine processes that end in the outer plexiform layer. H2-cells do not have a discernible axon.