RETINA. 



which they form. Slender fibers which arise from the outer surface of 

 this membrane and surround the bases of the rods and cones in the form 

 of baskets, may be regarded as prolongations of the radial fibers. The 

 inner ends of the radial fibers form pyramidal expansions which unite with 

 one another to make a membrana limitans interna. the innermost layer 

 of the retina. Throughout their course the radial fibers give off lateral 

 expansions and processes, for the support of the nervous elements; these 

 are especially numerous in the outer nuclear layer. Their nuclei are 

 among those of the inner nuclear layer. The nerve cells of this layer are 

 chiefly small bipolar ganglion cells constituting the ganglion retinae. 

 The dendritic process of each extends into the outer reticular layer, where 



Cone cell. 

 Rod cell. 



Stellate ganglion cell. 

 Bipolar cells. 



Amakrine cells. "'- 

 Centrifugal nerve fiber. - . 



Multipolar ganglion cell. - 



^- Layer of rods and cones. 

 J 

 | | Membrana limitans 



externa. 

 " Outer nuclear layer. 



Q09 Henle's fibre layer. 



*r Outer reticular layer. 



Inner nuclear laver. 



. Inner reticular layer. 



Ganglion cell layer. 



== = Nerve fiber layer. 



Collateral. Pyramidal bases 

 of radial fibers. 



FIG. 412. DIAGRAM OP HUMAN RETINA. SUPPORTING SUBSTANCE RED. 



by forking it breaks up into very fine fibers parallel with the surface. 

 They form a subepithelial feltwork and have been said actually to anas- 

 tomose. All the bipolar ganglion cells send their longest dendrite between 

 the visual cells where it ends in a little thickening near the membrana 

 limitans. The neuraxons of the bipolar cells pass into the underlying 

 inner reticular layer and there break up in fine varicose branches. 



The inner nuclear layer near its outer boundary contains stellate cells, 

 sometimes large, which send many dendrites into the subepithelial felt- 

 work where they anastomose. Their neuraxons extend horizontally, and 

 may pass inward to join the fibers of the optic nerve (which is denied by 

 some) or they may terminate in horizontal branches which ascend to the 



