This particular item is hidden in the ceiling, where you cannot get to it. The map circles are always accurate, even if looking around the room suggests otherwise more often than not, the items are hidden. This circle indicates that there is an item (such as an Energy Tank) in this room. In this room, if you check your minimap (or press Start and view the full map) you'll find a small white circle. (You'll have to wait until you get a later item until you can destroy the cracked floor.) Continue to the right. In the next room, note that the top platform can be destroyed by shooting it. Continue heading right, past where you started, until you reach a door. Activate the Morph Ball and roll under it. Return back the way you came since you cannot jump over the outcropping, you must go under it. Touch the red orb on top of the rock to obtain the Morph Ball.
