VETERIMAltY OPHTHALMOLOGY. 107 



Extends from the optic nerve to the ciliary processes, 

 where it is called the ora serrata. Consists of ten 

 layers. (1) The internal limiting membrane, separates 

 the nerve fiber layer from the vitreous, and the fibers 

 of Miiller terminate in this layer. (2) IVie nerve fiber 

 layer, consists of the axis-cylinder of the optic nerve 

 fibers, which run in a radiating direction to the ora 

 serrata, where they terminate. At the macula lutea 

 these fibers are bent into arches, and this arrangement 

 permits a larger number to reach the yellow spot than 

 if they approached in a radiating direction. (3) The 

 layer of ganglion cells, composed of multipolar cells, 

 each with a nucleus and nucleolus. A nerve fiber en- 

 ters each of these cells, and one or more prolongations 

 extend out into the inner molecular layer. These 

 ganglionic cells are arranged closer around the optic 

 nerve than at the ora serrata. (4) The internal molecu- 

 lar layer, one of the thickest, granulous in appearance. 

 Consists principally of fine fibers from the layer of 

 ganglion cells. (')) T/ie infer/ud granular layer, com.- 

 posed of two kinds of cells with nuclei. The larger are 

 nerve cells, having tico offshoots, one passing into the 

 inner granular layer, anastomosing Avith offslioots of the 

 ganglionic cells, the other out to the external molecular 

 layer and supposed to anastomose with fibers from the 

 layer of rods and cones. The smaller cells of this 

 layer are connected with the fibers of Miiller. (0) The 

 external molecular layer. Very thin and is made up of 



