Google SEA SHELL BORING ANIMALS. . . .lots of info, San Diego Nat Hist museum is one.
I was well aware of all the shell on the Tx coast with small holes in them, I was willing to give this one a positive human intervention because of the very symetrical hole and it looks like a formed exterior.
As luck would have it, there is a beautiful non animal bored hole on the front page right now. IF there was a hint of edge trim on the beach find, that would be a positive.
On the big negative side...around the main through hole there are other "hole" depressions...Those are NOT consistant with the twisting of a flint drill bit..
Fraid I side with Field as it being a natural object..