Fig. 15 — Normal animal Avith vibrissae on maze without sides Notice the 

 position in center of track, the way the feet are placetl, the lifted head and body, 

 the free movement, etc. 



Fig. l(i — Blind rat without vibrissae. Notice the flattened I)ody and the use of 

 toes and nose on the edge of maze. 



Plate II 



