Five views of a shell of Tonna galea, a species of marine gastropod mollusc in the family Tonnidae. The shell is very large, with an average height of 6 inches (150 mm), but thin and inflated (though relatively durable); as such, the shell weighs considerably less than most other gastropod shells of similar size.
From left to right: Dorsal, lateral (right side), ventral, back, and front view.Photograph: H. Zell; edit: Heinrich Pniok