356 



HISTOLOGY. 



epithelium and anteriorly by the epidermal ectoderm. The cornea is 

 extremely transparent. The epidermal ectoderm extends from the cornea 

 over two folds which form the eyelids. They have met in Fig. 409, D, 

 and fused temporarily. Externally the lids are covered by skin, internally 

 by the conjunctiva palpebrarum, or conjunctiva of the lids. The latter is 

 continuous with the conjunctiva bulbi which forms the opaque, vascular 



Epithelium 



Anterior basal lamina 



Substantia propria 



, Posterior basal lamina 

 -' Mesenchymal epithelium 



of the cornea. 



, Sphincter muscle 



.. Stroma \ of the iris. 



Pars iridica retinae j 



Angle of the iris. Sinus venosus sclerae 



Epithelium 1 of the 

 Tunica [ conjunctiva 



propria J bulbi. 



Sclera. 



Zonula. Ciliary process, muscle fibers. 



Circular Meridional Pars ciliaris retinae. 



WW^ Capsule 

 I Epithelium 



Fibers 



FIG. 410. MERIDIONAL SECTION OF A PART OP THE EYE. X 15. 

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



"white of the eye." It surrounds the cornea, the epithelium of the two 

 structures forming an uninterrupted layer. 



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

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

 ectodermal; then the tunica vasculosa including the chorioid, ciliary 

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

 and finally the accessory structures, the lids, conjunctivae and glands. 



