Marines explain their military occupational specialities to future Marines, also known as poolees, during a tour of the USS Arlington (LPD-24) amphibious dock transport ship, March 14, in South Boston, Massachusetts. More than 100 Marines from U.S. Marine Forces Command and the II Marine Expeditionary Force sailed to Boston aboard the ship to march in the St. Patrick's Day parade, participate in community relation events and interact with the public.