794 



DISSECTION OF THE EYE. 



anterior eyeball. When viewed on the eye in which the ciliary muscle is- 

 n; entire, it appears to terminate there ; but it may be seen in the 

 other dissections to pass inwards behind the muscle, and to end im 

 a series of projections (ciliary processes) at the back of the iris. 



This covering is rather thicker and stronger behind than in 

 front. Its outer surface is for the most part only slightly attached 

 to the sclerotic by delicate bands of areolar tissue, and has a floccu- 

 lent appearance when detached ; but in front the ciliary muscle 

 unites the two coats more firmly : on this surface may be seen 

 small veins arranged in arches, and the ciliary arteries and nerves 

 (fig. 289). The inner surface is smooth, and is lined by the thin 



relations of 



outer 



surface, 



of inner : 



FIG. 289. VIEW OF THE FRONT OF THE CHOROID COAT AND IRIS EXTERNAL 

 SURFACE (ZINN). 



. Sclerotic, cut and reflected. 



b. Choroid. 



c. Iris. 



d. Circular. 



e. Radiating fibres of ciliary 

 muscle. 



/. Ciliary nerves, and g, ciliary 

 arteries, between the two outer 

 coats. 



h. Veins of the choroid coat (vasa 

 vorticosa). 



opening 

 behind. 



Ciliary 

 processes : 



arrange- 

 ment ; 



two kinds 



dark pigmentary layer of the retina (fig. 288). Posteriorly it is 

 pierced by a round aperture for the passage of the optic nerve ; 

 and anteriorly it joins the iris. 



The ciliary processes (fig. 290, 6) are solid projections on the 

 inner surface of the choroid coat, disposed radially, and forming a 

 circle beneath the ciliary muscle and the outer margin of the iris. 

 About seventy in number, they comprise larger and smaller 

 eminences, the former being the more numerous, and having a 

 length of about one-tenth of an inch. They increase in depth from 

 without inwards ; and at their inner ends they are united by 

 transverse ridges. 



