The distribution of the ganglion cells in the chicken retina was observed using the whole mount preparations.
Cell counts of the ganglion cell layer in the chicken were about 4,500,000 and this value was considerably numerous compared with those in mammals. The isodensity lines of the retinal ganglion cells in the chicken had an oval form increasing the density toward the central area and did not formed the visual streak shown in mammals living on the ground. These findings suggest the difference in the extent of the view field associated with the living habits.
The ganglion cells in the retina have been classified in three types; large sized α-, medium sized β- and small sized γ-type cells. And these have been different from each other in the physiological significance. The larger α-type ganglion cells were mainly observed in the peripheral regions differing from the distribution centering the central area in mammals.
