Republic 588c-e: . . Let's make an image of the soul . . . model the form of a many-headed monster, having a ring of heads of all manner of beasts, tame and wild, which he is able to generate and change at will . . . now make a second form as of a lion, and a third of a man, making the the first the largest, and the third the smallest . . . now join them, and let the three grow into one . . . next fashion the outside of them into a single image . . .    so that he who is not able to look within, and sees only the outer shape, may believe the whole to be a single human being. 

   Rational part = the little person within.
   Spirited, honor-loving part = the lion
   Appetites = animal heads 
      Tame heads = necessary appetites
      Wild heads = unnecessary, dangerous appetites