mi: 1:1 1: 



821 



(or ligament) " and the " ciliary body." The ciliary circle, ligament, or 

 >nii>tc!>' (niniiilit* albidus) varies in width from one to two millimetres; its 

 ruu face adheres closely to the sclerotic, and its internal is confounded 

 with the ciliary body ; the posterior border is continuous with the 

 choroid zone, near the canal of Fonlana (ciliary canal). The anterior 

 larder gives attachment to the greater circumference of the iris. Its 

 structure and uses will bo referred to hereafter. 



The ciliary body (corpus ciliare) forms a kind of zone or ring, wider than 

 the ciliary ligament, and consequently overlaps the latter before and 

 behind. It extends, on one side, on the inner face of the choroid, and on 

 the other, on the posterior face of the iris. When the cornea and sclerotic 

 are removed so as to expose the ciliary ligament, this zone is not seen ; and 

 to discover it, it is necessary to excise all the posterior part of the shell of 

 the eye by a circular incision, and evacuate the vitreous humour. We then 

 observe, around the crystalline lens, a wide, black circle, forming very 

 regular radiating folds (ciliary processes) projecting inwards by their inner 

 extremities, and appearing in the posterior chamber of the eye, after cutting 

 away the iris ; all abut by these extremities on the circumference of the 

 h-iis, which they do not quite reach, although the latter is sustained by, and 

 in, the middle of the ligament. 



These radiating folds (Fig. 384,4) are from 110 to 120 in number in the 

 Horse, and are constituted by little parallel leaves, wider at their inner than 

 their outer extremity ; the furrows that separate them posteriorly are 

 partly concealed by the prolongation of the retina that constitutes the 

 zonula of Ziun. The coronet formed by the ciliary processes is usually 

 asymmetrical. 



(Between the sclerotic, the cornea, and the ciliary ligament, exists a 

 minute circular canal the ciliary canal, 

 canal of Schlemm, sinus circularis iridis, 

 his venosus orbiculi ciliaris, or canoZ of 

 Fi'titana, from its discoverer. It is sur- 

 mised to be a venous sinus, as it can 

 always be injected from the arteries.) 



STBUCTUUE. The choroid zone is com- 

 posed of four superposed layers: 1, The 

 nal is formed by a network of c<m- 

 ii'-rtive elastic fibres, among which are 

 disseminated a great numlwr of pigim nt 

 cells ; 2, The second layer is constituted by 

 a network of large arteries and veins 

 the posterior ciliary and a plexus of 

 nerves (ciliary) accompanied by ganglia and 

 some (stellate) pigment cells. (The veins 

 are arranged with great regularity in droop- 

 ing branches, to form the vata vorti<"X<i 

 (Fig. 386, 2, 4); these are chiefly on the 

 outer surface of the layer, the ar: 

 ramifying on the inner surface.) 3, The 

 third loyer, or tunica ]{nym-liinna, has for 

 its basis an amorphous substance containing 

 a network of exceedingly fine capil! 



Ffg. 384. 



MKST OK A TKAXSVKR8I 

 SECTION OK THK SUOBI "I HIE KYK 

 (HO! AN). -I I N KUOM WITHIN. 



I, l>ivided edge of the three tunics, 

 sclerotic, chon>i<l (the ilark l-i\i-r), 

 ami retina; '_', Pupil : 



> ; "'. I ' n- 



tii-iilateU anterior bonier of the 

 . . .. . 



(extending to the ciliary processes); 4, The 



// liycr is composed of hexagonal nils, r> 'iilu-ly [ i 



the 





