668 



THE EYE 



The polar figures formed by the lines of terminal union of the lens 

 fibers are known as lens starts; these are at first three-rayed, but later 

 become six- and even nine-rayed. 



During the earlier stages of the development the lens is invested 



i ". -^,.m 

 I 





FIG. 565. THE NUCLEAR ZONE AT THE MARGIN OF THE CRYSTALLINE LENS OF A 

 CHILD'S EYE, SHOWING THE TRANSITION OF THE LENS EPITHELIUM TO THE LENS 

 FIBERS AND THE ATTACHMENT OF THE SUSPENSORY LIGAMENT. 



a, lens fibers; b, lenticular epithelium; c, capsule of the lens; d, suspensory liga- 

 ment. Hematein and eosin. X 273. 



by a delicate vascular membrane, the tunica vasculosa lentis (designated 

 pupillary membrane in front), supplied by the hyaloid artery continued 

 from the central artery of the retina. This tunic normally disappears 

 before birth ; its atypical persistence in whole or in part seriously inter- 

 feres with vision. 



