i6 



OPHTHALMOLOGY FOR VETERINARIANS 



mentary structure. Its function is to nourish the eye 

 and absorb Hght. It extends from the optic disk to the 

 ora serrata. 



Histologically, the chorioid consists of five layers. 

 First, from without inward, the suprachorioid, inti- 



Fig. 4. — Vascular tunic of eyeball of horse, front view. The cornea 

 is removed and the sclera is reflected in flaps: i, Sclera; i', lamina fusca; 

 2, choroidea; 2', ciliary veins; j, ciliary muscle; 4, iris; 5, 5', granula 

 iridis; 6, pupil, through which the lens is visible. (After Ellenberger, in 

 Leisering's Atlas.) 



mately connecting it with the sclera; second and third, 

 are two layers of vessels, large and small respectively, 

 embedded in a stroma of connective tissue with numer- 

 ous branched pigment- cells; fourth, the lamina ruyschii, 



