488 THE HUMAN BODY 



apparatuses and nerve-tissues, and partly accessory struc- 

 tures. 



Beginning (Fig. 126) on the front side we find, first, the- 

 internal limiting membrane, 1, a thin structureless layer. 

 Next comes the nerve-fibre layer, 2, formed by radiating 

 fibres of the optic nerve; third, the nerve-cell layer > 3; 



FIG. 125. The right retina as it would be seen if the front part of the eyeball 1 

 with the lens and vitreous humor were removed. 



fourth, the inner molecular layer, 4, consisting partly of 

 very fine nerve-fibrils, and largely of connective tissue;, 

 fifth, the inner granular layer, 5, composed of nucleated 

 cells, with a small amount of protoplasm at each end, and 

 a nucleolus. These granules, or at any rate the majority 

 of them, have an inner process running to the inner 

 molecular layer and an outer running to, 6, the outer 

 molecular layer, which is thinner than the inner. Then 

 comes, seventh, the rod^jand cow fibx&Jayer, 7, or outer 

 granular layer; composed of thick and thin fibres on each 

 of which is a conspicuous nucleus witli a nucleolus. Next 

 is the thin external limiting membrane, 8, perforated by 

 apertures through which the rods and cones, 9, of the ninth 

 layer join the fibres of the seventh. Outside of all, next 

 the choroid, is the pigmentary layer, 10. In addition, cer- 



