Is it called Shoulder Roll, Philly Shell, or Crab Defense

[PEBBLES!]

Shoulder roll is a component of the Philly shell. The former belongs to the latter, hence they shouldn't be listed seperately.

[Tiozzo]

Crab defense is what Ken Norton, Lamotta and George Foreman all used. It's where you cross your arms in front of your torso and chest, and then block with your forearms according to where they are striking.

The 'philly shell' is a separate stance as a whole, and 'the shoulder roll' is merely one of the techniques used (usually to deflect right crosses) while in the "philly shell" stance.

Foreman didn't get low as the others though. I wonder if we can still call it crab defense?