426 NORMAL HISTOLOGY AND ORGANOGRAPHY. 



elements that constitute the different layers of the 

 retina through which they pass. 



In certain areas of the retina there are peculiar- 

 ities that differ from the above description. These 

 areas are: (i) the macula lutea, or yellow spot; 

 (2) the optic papilla, or blind spot; (3) the ora ser- 

 rata; (4) the pars ciliaris retinae ; (5) the pars iridica 

 retinae. 



i. The macula lutea, or yellow spot, is a crater- 

 like area of the retina that lies in the visual axis of 



Fovea centralis. 



Ganglion cell 

 layer . 



Inner molecu- 

 lar layer. 



Inner nuclear 

 layer. 



Outer molecu- 

 lar layer. 



Outer fibrous 

 layer. 



Fig. 293. Section through human macula lutea and fovea centralis. 

 As a result of treatment with certain reagents, the fovea centralis is deeper 

 and the margin more precipitous than during life (Bohm and Davidoff). 



the eye. The central depression is called the fovea 

 centralis. Its margin is somewhat thickened and 

 presents all the layers of the retina, while in the fovea 

 the layers are practically reduced to the cone-visual 

 elements. From this center the cell bodies of the 

 cones radiate in curves to reach the outer molecular 

 layer, which gives rise to obliquely directed fibers 

 known as Henle's fiber layer. The macula lutea is 

 the most sensitive spot in the retina and derives its 



