38 THE EMBRYOLOGY OF THE EYE. 



that the nearest nuclei are separated from the 

 epithelium by a fibrous layer similar to the 

 corneal stroma as the stroma appears some- 

 what later. This layer after It Is formed has 

 about the thickness of a corneal lamella, and 

 does not Increase In thickness In later foetal 

 life like the membranes of cuticular formation. 

 It has a sharp outline next the epithelium, and 

 the epithelium is readily stripped cleanly off 

 it, but It is not at any period sharply limited 

 from the corneal stroma and It cannot be 

 readily separated from the latter. It stains 

 much the same as the corneal stroma, and is 

 similarly affected by pathological processes. 

 It would seem to be an early product of the 

 corneal cells, being fully formed at a time 

 when the rudimentary cornea Is still com- 

 posed of splndle-cells, and distinct fibrous 

 tissue has not yet made Its appearance else- 

 where. 



In birds the development of Bowman's 

 membrane Is different. The space between 

 the lens and the external epithelium Is filled 



