ANATOMY OF THE EYE. 



559 



of the eyeball, the choroid is useful in vision by preventing the 

 reflection of the light from the background of the eye in such 

 a way as would cause irregularity of its distribution, and thus 



FIG. 216. 



Pigmented epithelium lying next to 

 the choroid coat. 



Rods and cones with their extremities 

 imbedded in the epithelial cells. 



External nuclear layer. 



External granular layer. 



Internal nuclear laver. 



Internal granular layer. 



Layer of nerve cells. 



Nerve-fibre layer in which the retinal 

 vessels run next to the vitreous 

 humor. 



Diagrammatic section of retina, showing the relation of the different layers in the pos- 

 terior part of the fuudus (not the macula lutea). (Schultze.) 



dazzle and interfere with the distinctness of the image. The 

 choroid, also, is elastic, and can move over the neighboring 

 sclerotic; it can be drawn forward by the contraction of the 



