Stars and Constellations
There are many different types of galaxies.  There are spiral galaxies such as the Milky Way, Andromeda Galaxy, or Whirlpool Galaxy in Canes Venatici.  Other types of galaxies include Seyfert galaxies, Elliptical galaxies, Irregular galaxies, Peculiar galaxies, and Barred spiral galaxies. 
Spiral Galaxy- Has arms that trace out in a spiral form.  They usually consist of hot blue-white stars and glowing red gas.  This mixture circles around a yellow core. 

Seyfert Galaxy-Are spiral systems with bright centers.  These galexies were named after Carl Seyfert.  He first noticed them in 1942, these galaxies are part of a continuum of  "active" galaxies with unusual core activity.  Often the activity is violent. 

Elliptical Galaxies-The stars in this kind of galaxy vary in size form dwarfs to giants.  The largest galexies we see are the giants.  They often dominate the center of a cluster, probably growing from collisions with spiral galaxies.