[Skunkworks] how to untar a specicic sub directory in a tarred directory

Skunks i have a tarred directory in a linux server which is like 300gb and i need to untar a specific sub directory (i can untar the whole dir but i simply dont have the space) in that tar directory..... can any skunkhead out there think of a command that can put me out of my predicament...google has failed me so far and the clock is ticking