THE SEX.SKS. 



69? 



are derived from the ciliary nerves. They traverse the substance of the 

 cornea, in which some of them near the anterior surface break up into axis 

 cylinders, and their primitive fibrillge. The latter form a plexus imme- 

 diately beneath the epithelium, from which delicate fibrils pass up 

 between the cells anastomosing with horizontal branches, and forming a 

 deep intra-epithelial plexus, from which still finer fibres ascend, till near 

 the surface they form a superficial intra-epithelial net-work. Most of 

 the primitive fibrillse have a beaded or varicose appearance. The cornea 



Fig. 410. 



Fig. 411. 



Fig. 410. Vertical section of rabbit's cornea, stained with gold chloride, e, Laminated 

 anterior epithelium. Immediately beneath this is the anterior elastic lamina of Bowman, n, 

 Nerves forming a delicate sub-epithelial plexus, and sending up fine twigs between the epithelial 

 cells to end in a second plexus on the free surface ; d, Descemet's membrane, consisting of a 

 fine elastic layer, and a single layer of epithelial cells; the substance of the cornea, /, is seen 

 to be fibrillated, and contains many layers of branched corpuscles, arranged parallel to the free 

 surface, and here seen edgewise. (Schofield.) 



Fig. 411. Section through the choroid coat of the human eye. 1, elastic membrane, struc- 

 tureless or finely fibrillated; 2, chorio-capillaris or tunica Ruyschiana; 3, Proper substance of 

 the choroid with large vessels cut through; 4, suprachoroidea ; 5, sclerotic. (Schwalbe. ) 



has no blood-vessels penetrating its structure, nor yet lymphatic vessels 

 proper. It is nourished by the circulation of lymph in the spaces in 

 which the cornea corpuscles lie. These communicate freely and form a 

 lymph-canalicular system. 



Structure of the Choroid Coat (tunica vasculosa). This coat is 

 attached to the inner layer of the sclerotic in front at the corneo-scleral 

 junction and behind at the entrance of the optic nerve, elsewhere it iff 



