Possible Clues:

• Fourth compartment of ruminant's stomach
• Fourth compartment of the stomach of a ruminant
• Ruminant's fourth stomach
• The fourth stomach found in animals such as 21
• American Mafia makes a comeback - it's a lot to stomach in an inhuman way
• Obama wrestling with problem requiring bit of guts
• A cow's fourth stomach
• Ruminant stomach
• Old mother's filling a hobo's stomach
• Sailor finds worthy folk a lot to stomach