THE CORNEA 



631 



the tough, white, sclerotic coat; the intermediate thin, vascular, pigmented 

 choroid coat; and the inner nervous coat, the retina. 



The section also shows that the eyeball is specialized in structure in its 

 anterior region and that its contained cavity is divided into two parts, viz., 



Posterior chamber 



Canal of Schlemro 



Suspensory liga! 



Equator 



FIG. 441. Section of the Eyeball. 



the anterior and posterior chambers are filled with the transparent aqueous 

 fluid. This fluid is like lymph in its composition. The vitreous chamber 

 between the lens and the retina is filled with the clear jelly-like vitreous 

 substance. 



The Cornea. The sclerotic coat is continuous with the cornea in 

 front of the eyeball, but the cornea is transparent and its radius of curvature 



FIG. 442. Vertical Section of Rabbit's Cornea, a, Anterior epithelium, showing the different 

 shapes of the cells at various depths from the free surface; b, portion of the substance of cornea. 

 (Klein.) 



is less than that of the main portion of the eye. It is composed of strati- 

 fied epithelial cells, and is richly supplied with sensory nerves that form 

 an intra -epithelial plexus of delicate varicose fibrils. The cornea has no blood- 

 vessels, but has a rich network of lymphatic spaces. 



