THE CHOROIP COAT. 



In addition to the nerves which are destined for the epithelium, others, for 

 the proper substance of the cornea, come off from the primary plexuses, and, 

 after uniting into one or more secondary plexuses, the cords of which are still 

 composite, eventually form, in and among the laminag, a terminal ramification of 

 ultimate fibrils, the meshes of which are much more open than those of the intra- 

 epithelial network (see fig. 25). An actual connection of these nerves with the 



Fig. 24. VERTICAL SECTION OF RAB- 

 BIT'S CORNEA, CHLORIDE OF 

 GOLD PREPARATION. (Ranvier.) 



n, r, parts of fundamental plexus ; 

 a, vertical branch passing to sub- 

 epithelial plexus, s ; p, b, inter- 

 epithelial ramification. 



corpuscles of the cornea pro- 

 bably never occurs ; although, 

 since the fine nerve-fibrils 

 run in the anastomosing cell- 

 spaces, they come into close 

 connection with the cor- 

 puscles and their processes, 



and they have therefore been described by some observers as being actually con- 

 tinuous with the latter. 



The larger branches of the nerves are covered with a sheath of flattened cells 

 which, as before mentioned, are in connection with the corpuscles of the cornea. At 



Fig. 25. CORPUSCLES AND NERVES 



IN THE SUBSTANTIA PROPRIA 

 OF THE CORNEA OF THE FROG; 

 CHLORIDE OF GOLD PREPARA- 

 TION. (Waldeyer.) 



1, bundle of fundamental 

 plexus ; 2, nucleus ; 3, terminal 

 tibril ; 4, corneal corpuscles. 



the points of junction of 

 the plexuses nuclei are 

 frequently seen (fig. 25, 2), 

 but these appear to belong 

 to the ensheathing cells, and 

 are not interpolated in the 

 course of the fibres. 



THE VASCULAR COAT. 



The vascular coat of the eye (tunica uvea s. vasculosa] lies within the corneo- 

 sclerotic coat, and consists of two parts, which are continuous with one another, 

 viz., the choroid and iris. The choroid is applied to the inner surface of the 

 sclerotic, and the retina is firmly attached to its inner surface ; the iris is attached 

 only at its circumference, otherwise floating freely in the aqueous humour imme- 

 diately in front of the lens, with which it comes lightly into contact, and separated 

 from the cornea by the depth of the anterior chamber. 



The choroid coat (tunica choroidea) is a dark brown membrane (black in most 

 animals) lying bettf eet^ the sclerotic and the retina. Anteriorly it is continued into the 

 iris, but before it passes into this it forms a number of radial thickenings named ciliary 



