inner surface is separated from the internal layer of the 

 cornea by Descemet's elastic limitary membrane. 



The internal layer is composed of a single layer of many 

 sided cells which contain large neuclei. The cornea has but 

 few blood vessels. The vessels form loops around its border, 

 and in the sheep they advance to the middle of its surface. 



The middle coat of the eyeball consists of the choroid, 

 the ciliary processes and the iris. 



The choroid is a thin, vascular, dark colored membrane, 

 spread over the inner surface of the sclerotic, investing the 

 posterior four-fifths of the eyeball, and terminating, in front, 

 at the ciliary ligament; there bending inward to form the 

 ciliary processes. 



The choroid is divided into two zones or unequal parts by 

 the ora serrata — a zigzag line that corresponds to the point 

 where the retina changes its character or near the anterior 

 border of the retina. The posterior zone or part, in the 

 horse, is not uaiform in color, being perfectly black in the 

 lower part; this is abruptly terminated at a horizontal line 

 that passes about one-eighth of an inch above the place 

 where the optic nerve passes through the sclerotic and 

 choroid. From this line on the segment of a circle from 

 two to three-fifths of an inch in height it shows most bril- 

 liant colors: at first blue, then an azure-blue, afterwards a 

 brownish blue, and after this the remainder of the eye is oc- 

 cupied by an intense black. The bright portion, or upper 

 half of the choroid is the fapetum. The anterior zone or 

 ciliary part of the choroid includes the ciliary ligament and 

 the ciliary body. The ciliary muscle circle or ligament is a 

 gravish circular band of uustriped muscular fibres about 

 one-sixteenth of an inch broad; the fibres are radial and cir- 

 cular, the former arises from the junction of the cornea and 

 sclerotic to pass back to the choroid opposite the ciliary pro- 

 cesses; the latter are internal and pursue a circular course 

 around the place of attachment of the iris. 



