THE OCULAR CONTENTS 



593 



the neuro-epithelial portion of the retinal layers. The vena cen- 

 tralis retinas pursues a course exactly similar to that of the artery. 



The Ora Serrata (Fig. 

 417). At the ora serrata 

 the typical layers of the ret- 

 ina, already much thinned, 

 abruptly cease. They are 

 continued forward only as 

 the double layer of epithe- 

 lial cells belonging to the 

 pars ciliaris retinae, the in- 

 ner stratum of which ap- 

 pears to be analogous to 

 and continuous with the 

 cerebral portion of the ret- 

 ina, while the outer, deep- 

 ly pigmented layer appar- 

 ently represents the outer 

 or neuro-epithelial portion 

 of the retinal tissues. 



THE OCULAR CONTENTS 



AVi thin the ocular globe, 

 whose walls are formed by 

 the three coats of the eye, 

 are certain structures 

 which may be collectively 

 considered as its contents. 

 They are : 



1. The aqueous humor. 



2. The crystalline lens. 



3. The vitreous humor. 



4. The hyaloid mem- 

 brane. 



5. The suspensory liga- 

 ment. 



THE AaUEOUS HU- 

 MOR The aqueous hu- 

 rnor is a fluid, closely 

 allied to lymph, which occupies the anterior and posterior cham- 

 bers of the eye. Microscopically it is structureless. 

 39" 



