Whereas knowledge of the structure of the anterior segment of the eye has been greatly enlarged in recent years by slit-lamp studies of the living eye, the present knowledge of the structures of the angle of the anterior chamber is still based almost solely on information acquired from the classic method of anatomic dissection and microscopic section of dead tissue. Information obtained from a study of the angle of the living eye (gonioscopy) has, as yet, hardly been correlated with it. In spite of this rather indefinite correlation, steady progress has been made in the observations on the angle in the living eye since the angle was first seen by Trantas,1 who introduced the term gonioscopy for this type of examination. In succeeding years the method was further developed by Fick,2 Salzmann,3 Koeppe,4 Troncoso,5 Ascher6 and others, so that Troncoso, who popularized the term