The Structure of the Retina
Next to the choroid and comprising about 1/4 the entire thickness of the retina is a multitude of transparent, colorless, microscopic rods (a) evenly arranged and packed side by side, like the seeds in the disk of a sunflower. Among them at regular intervals, are interspersed the cones (b). Delicate nerve fibers pass from the ends of the rods and cones, each expanding into a granular body (c) thence weaving a mesh (d) and again expanding into the granules (f). Last is a layer of fine nerve fibers (g) and gray, ganglionic cells (h) like the gray matter of the brain, whence filaments extend into the fibers of the optic nerve (i).