Of the 16 clubs that existed unchanged for fifty years (1902-52), the following legendary names no longer exist as living, breathing entities in their original cities:
St. Louis Browns
Washington Senators **
If the new 3rd incarnation of a Washington club in 2005 really wants the name "Senators", they will have to buy it from the Texas Rangers, who own the rights from their brief term in Washington as the 2nd coming of that club.
New York Giants