582 



KARL T. WAUGH 



If the animal possesses the requirements estimated above, there 

 is good reason to suppose that it has binocular vision in the proper 

 sense. 



A piece of anatomical work undertaken to supplement the 

 experiments on behavior was that of measuring the angle of 

 divergence of the optic axes, and determining the angular field of 

 possible binocular vision. The results appear in fig. 8. In a head 

 from which the eyes had been removed the optical axis was ob- 

 tained by drawing a line from the fundus of the eye-socket through 



Fig. S The field of vision of a mouse, r, right monocular field; I, left monoc- 

 ular field, rl, binocular field; o, o, optic axes. 



a point equally distant from all points in the rim of the opening, 

 outward into space. The limits of the field of vision were deter- 

 mined by the points from which the eye could be plainly seen. 



Although the axes of the conical eye-sockets in the mouse 

 diverge greatly, forming an angle of about 100 degrees, yet, o wing- 

 to the prominence of the eyes themselves, it is quite possible that 

 they may receive images from the same object simultaneously. 



