122 OPHTHALMOLOGY FOR VETERINARIANS 



character, but must produce more or less irritation of the 

 iris in its movements of contraction and dilatation. 



Sarcoma sometimes makes its appearance inde- 

 pendently in the ciHary body and iris, but is more often 

 extended to these portions from primary affection of the 



Fig. 28. — ^The contents of the left orbit in Fig. 24, cut in the center 

 from above downward: a, the eyeball; 6, the retractor muscle; c, the 

 normal tissue; d, the tumor mass. 



chorioid or the anterior portion of the eye. It is pig- 

 mented (melanotic), and when it is confined to the 

 ciHary body it cannot be seen or discovered until it has 

 reached a sufhcient size, as the ciliary region is always 

 difficult to see with the ophthalmoscope because it is 

 located so far anteriorly. Its location may be deter- 



