AND PHYSIOLOGY. 



371 



682. Choroid Coat.— Iris. ». 340. 



— Ciliary Processes.— The 

 middle coat of the eye is 

 made up of three portions, 

 the Choroid membrane, the 

 Iris, and the Ciliary pro- 

 cesses. The first, Choroid, is 

 named from the fact that it is 

 entirely made up of blood- 

 vessels, of a chocolate-brown 

 color on the outside, and a 

 deep black on the inside. It 

 covers the posterior four fifths 

 of the eye, and corresponds 

 to the sclerotic coat outside 

 of it. The Iris, so called from 

 the diversity of color which 



Plan of the Structures in the Fore Part of the Eye, seen in Section. 1, Conjunctiva. 

 2, Sclerotica. 3, Cornea. 4, Choroid. 5, Annulus Altudus; before this is is seen the 

 Canal of Fontana. 6, Ciliary Processes. 7, Iris. 8, Retina. 9, Hyaloid Membrane. 10, 

 Canal of Petit (made too large). 11, Membrane of the Aqueous Humor (too thick.) «, 

 Aqueous Humor; Anterior Chamber, and (a,) Posterior Chamber. &, Crystalline Lens, 

 c, Vitreous Humor. 



Fia. 341. 



Choroid Coat of the Eye. 1, Curved lines marking the arrangement of Vena? Vorti- 

 cosae. 2, 2, Ciliary Nerves. 3, A long Ciliary Artery and Nerve. 4, Ciliary Ligament. 

 5, Iris. 6, Pupil. 



632. Of what three portions is the choroid coat composed ? Give their names. De- 

 scribe the Iris. 



