My first ever large Hammerhead (in which I pursued for over a week, and if you scroll down you can WATCH the whole days Video) was exactly what I told Nick (1st mate) it was when it got close enough for a good look.
There's the Great Hammerheads - straight across front of "hammer"
Then there's the Smooth Hammerheads - Smooth spot across the "hammer"
And then the Scalloped Hammerheads - As it says, "Scalloped shape" across the "hammer"
Mine was a "Scalloped Hammerhead" if we're looking to get down to the brass tacks.
HERE's THE MAN, Capt Mark explaining: