IN A STUDY of patterns of eye movements obtained on electric stimulation of the brain stem, cerebellum, and cerebrum in the monkey, there was one type of binocular action which has seldom been mentioned in the conventional classification of eye movements. This was a centering of the eyes to the midposition regardless of the location of the globes prior to the stimulation. Magoun, in his earlier investigations of the brain stem, recorded such eye movements in his protocols, but he did not attach particular significance to them. In our preliminary note, made in 1948, we called this ocular movement "the midposition phenomenon."1The same phenomenon had previously been observed by others who investigated cerebral function. In 1888 Beevor and Horsley2and in 1890 Mott and Schaefer3noted this centering in their observations on stimulation of the frontal lobe. Brown4interpreted this midpositioning as "the orientation of