VISION IN THE MOUSE 599 



adapted to the distinguishing of such few color contrasts as may 

 be of importance in its life and habits. 



8. There is no fovea or other structurally differentiated por- 

 tion in the eye of the mouse. The range of vision is very wide, 

 all parts of the retina being equally sensitive, a condition which is 

 enjoyed at the sacrifice of distinct perception of form. 



9. There is possible for the mouse a small field of binocular 

 vision. This is not used for estimating distance, as there is no 

 convergence of the eyes. It is of service rather as a means of 

 orientation. 



10. The kinaesthetic sense is more important than vision in 

 determining the actions of the mouse. The latter is of use in 

 indicating the presence and general direction of an enemy. Food 

 is found largely through the sense of smell. In other words, 

 smell is an active sense; vision is a protective or passive sense, 

 while the behavior of the animal is largely the result of motor 

 habits, formed through kinaesthetic sensations. 



