Phillip is the 16th Earl of Haddenfield and a shark hunter. He is the shark's fourth victim. He is devoured while trying to kill the shark with a grenade. At the end of the movie, his arm is seen with the grenade still in hand in the shark's mouth, which is used to ultimately detonate and blow the shark's head apart.
Phillip is swallowed whole, but escapes the shark's jaws, just to be smashed inside the Shark's guts, having one of the most gruesome and painful deaths of all movies.
A close up when Michael Brody is able to pull the pin of the grenade still in Phil's hand inside the Shark's mouth, Phil was pivotal to the destruction of the Shark, his "Mill's bombs" made by a "chap" from the royal ordinance blow the shark apart.