34 THE EMBRYOLOGY OF THE EYE. 



7). The anterior epithelium at this stage is 

 continued far back behind the equator of the 

 lens, and the nuclei of the fibres are bunched 

 together in the form of a crescent with its 

 convexity forward. As the lens develops, the 

 cells farthest back in the anterior epithelial 

 layer become lens-fibres in their turn, and the 

 limit of the epithelial layer gradually moves 

 forward (Figs. 7, 8, 9). At the same time the 

 layer decreases in thickness until it comes to 

 consist of a single stratum of cells, which ter- 

 minate near the equator of the lens (Fig. 9), 

 and which are permanent. The nuclei of the 

 fibres become more scattered, and lose to 

 some extent their regular arrangement (Fig. 

 8), and the curve of the individual fibres 

 changes, those near the equator of the lens 

 curving but slightly outward, and those nearer 

 the axis curving slightly inward. This change 

 in curvature increases, and in the matured 

 lens most of the fibres curve sharply inward 

 and run concentrically. 



From the time when the lens-sac is first 



