Sesame Street - X Marks The Spot lyrics

Egad! Sherlock Hemlock here, the worlds greatest detective And I believe the letter following "W" is... "X" marks the spot "X" marks the crossroads Two straight lines crossing Over in the middle That's the letter you must see to Find the treasure or the clue Or the X-ray machine that's Looking right inside of you "X" is the letter without which One could not do "X" marks the spot "X" stands for danger Two straight lines crossing Over in the middle Saying "Here's the railroad crossing" And sometimes it means there's pirates Or at worse, it means there's poison And in case these thoughts of "X" Are vexing you "X" stands for "xylophone," too