Swan Song - Level 3 help

[clalbo]

I'm stuck in Swan Song on Level Three (Cocopuff caverns).
I just got the bow, and I'm trying to go to the dark-brown boss areas, but I can't for the life of me find out how to get there.

I'm guessing it has to do with the room that has a crystal ball, a bunch of boomerang tossers, and tall square-block walls that divide the room into thirds. The map says there's a room beneath this room, but I can't find how to get there. All help is appreciated.

also i stuck in this area