Retinal ganglion cell topography in the masked greenling Hexagrammos octogrammus (Pallas, 1814) (Pisces, Scorpaeniformes, Hexagrammidae).

The spatial arrangement of retinal neurons determines to a certain extent visual acuity and sensitivity. Despite a large number of studies dealing with retinal topography, there are gaps in our knowledge on the issue. We addressed the spatial arrangement of retinal ganglion cells in the masked greenling, a marine demersal fish. The combined proportion of displaced amacrine cells and glia was 17.63%. The spatial density of ganglion cells was lowest (1900-2500 cells/mm2) in the ventronasal periphery. It increased centripetally to form a horizontal visual streak situated dorsal to the optic disc. The peak spatial density values (11,900-15,400 cells/mm2) were registered in the dorsotemporal quadrant where a prominent area temporalis was found. The presence of area temporalis and visual streak is in line with the species' biology.