Differentiate between galaxies and constellations in points

Galaxy                                                                                         constellation:

I. A galaxy is a collection of millions of stars.                                A constellation is a collection of few countable numbers of                       stars. 

II. Galaxies dont form any imaginary shape.                                  A constellation can form pictures of animals or mythological                                                                                                    creature 

III. There are billions of galaxies in our universe.                           Number of constellation in our sky is only 88.