 The shell of this species was given the common name "Scotch bonnet" because of a vague resemblance to a tam o' shanter, a traditional tartan hat which used to be commonly worn in Scotland.The shell has a regular pattern of square or rectangular patches that are orange, tan, or brown in color.The shell can sometimes be smooth except for growth lines, but in other individuals it can have a sculpture of incised spiral grooves and even weak axial ribs which, together with the colored patches on the shell, create an effect that is reminiscent of the pattern of a Scottish plaid.