EYE 



443 



Fig. 451, D, and fused temporarily. Externally the lids are covered by 

 skin, and internally by the conjunctiva palpebrarum, or conjunctiva of the 

 lids. The latter is continuous with the conjunctiva bulbi which forms 

 the opaque vascular "white of the eye." It surrounds the cornea, the 

 epithelium of the two structures being continuous. 



The parts of the eye to be examined histologically are therefore the 

 retina, optic nerve, lens, and vitreous body, all of which are ectodermal; 



, - Epithelium 

 .. - Anterior basal lamina 

 r . Substantia propria 

 -Posterior basal lamina 



Mesenchymal epithelium 



Sphincter muscle 



oma 

 Pars iridica retinae 



of the cornea. 



of the iris. 



gle of the iris. Sinus venosus.sclerae 



- Epithelium "I o f tjj e 



_ . I conjunctiva 



- Tunica [ bulbi . 



propna J 



Zonula. Ciliary process muscle fibers. 



Sclera. 



Circular Meridional Pars ciliaris retinae. 



Corpus ciliare. 

 Capsule 



Epithelium I of the lens. 

 Fibers j 



FIG. 452. MERIDIONAL SECTION OF A PART OF THE EYE. X 15. 

 The radial fibers of the ciliary muscle cannot be distinguished with this magnification. 



then the tunica vasculosa, including the chorioid, the ciliary body, and 

 iris; next the tunica fibrosa, including the sclera and cornea; and finally 

 the accessory structures the lids, conjunctivas and glands. 



RETINA. 



The retina extends from the papilla of the optic nerve to the pupillary 

 border of the iris, and is divisible into three parts; the pars optica retina 

 includes all which is actually connected with the optic nerve and which 

 therefore is sensitive to light. It covers the deeper portion of the optic' 



