Open shells, particularly ones with spines and ribs, create a lot of drag; but more importantly, the orientation of the shell, with the body hanging below the buoyant part of the shell, would have created a serious impediment to efficient swimming.
Upprunaliga var vætan brúkt sum eldásetandi evni ímóti bygningum, men seinni fyrst og fremst sum bumba, av tí at napalm setur seg fast á húðina, og veldur stórum brunasárum, tá tað kemur í samband við eld.WikiMatrix WikiMatrix