ÜBER DIE ZENTRALISATION DER RETINA BEI PRIMATEN

Abstract

The histology of the retina was investigated in numerous species of primates. Only sections which were cut exactly through the center of the fundus were quantitatively evaluated, whereby the thickness of the various retinal layers and the number of nuclei found in the 3 cell layers were determined in each species in the same areas of the retina. In general, there are fewer receptors and connecting neurons per ganglionic cell in the central portions than on the periphery, although the absolute number of cell elements increases steadily toward the retina center. A striking result of the investigation is that the degree of centralisation increases with advance in evolution. From a morphological point of view 3 degrees of centralisation can be distinguished in the primates. The more diurnal the animals are, the higher the degree of centralisation is. It seems probable that the phylogenetic development of the centralisation of the retina begins in the forerunners of the Tupaiiformes.