22 OPHTHALMOLOGY FOR VETERINARL\NS 



ciliary body also by a ligament of loose tissue from near 

 the posterior portion of the sclerocorneal connection. 

 This Hgament is called the hgamentum pectinatum. 

 It has nearly a semicircular shape, and comprises the 

 angle between the sclerocorneal margin and the iris. 

 It is the extreme boundary of the anterior chamber 

 and a most important structure. 



The iris is described as ''a spongy sort of tissue/' 

 composed principally of numerous delicate blood- 



Fig. 7. — Iris of the horse, showing position of corpora nigra. 



vessels, radiating from the periphery toward the pupil, 

 and interspersed with a meshwork of branched and 

 pigment-cells. The anterior surface is covered with 

 epithelium (except the hollow spaces or crypts), which 

 is continuous with that on the posterior cornea. The 

 posterior surface is covered with a delicate membrane, 

 upon which rests a layer of pigment epithelium. This 

 membrane, with its fibers extending in a radial direc- 

 tion, constitutes the dilator pupillae muscle. The 



