THE LAYEES OF THE RETINA 



585 



epithelium are occupied by a homogeneous fluid, probably a some- 

 what modified lymph. 



3. The external limiting membrane (membrana limitans ex- 

 terna) consists of the flattened and amalgamated extremities of 





-1 



a 



FIG. 430. FROM A MERIDIONAL SECTION OF A CHILD'S EYE, SHOWING THE LAYERS OF THE 



RETINA AT A POINT MIDWAY BETWEEN THE MACULA LUTEA AND THE OHA SERRATA. 



Eeferenccs as in Fig. 429. Ileinatein and eosin. Photo, x 400. 



Mailer's fibres, which form the chief supporting tissue, the neu- 

 roglia element, of the retina, and which extend from the extreme 

 inner surface outward to the external limiting membrane. It will 

 therefore be more convenient to defer further description of this 

 membrane until the remaining layers have been described, and the 

 Mullerian fibres can be considered in their entirety. 



4. The outer nuclear layer (nnh-r yrtumlar layer) consists, for 

 the most part, of the nucleated portions of the rod and cone ele- 

 ments. The outermost zone of this layer contains only cone 

 nuclei ; the inner portion, comprising about three-fourths of its 



