Slide Show : Gastropod Shells

(Photo: Jean Allsopp)
1  |  2  |  3  |  4  |  5  |  6  |  7  |  8  |  9  |  10  |  11  |  12  |  13  |  14  |  15  |  16  |  17  |  18

Turret or Screw Shells
These large shells, sized between ¼ inch to 5¾ inches, have convex whorls and spiral coils, with a circular aperture. There are 17 species of turret or screw shells inhabiting North American waters.