Strong radiating ribs are common in this group; and there are generally very strong plications or accordion-like folds on the sulcus (the long middle section) of the shell. This probably helps regulate the flow of water in and out of the shell.
This species often exhibits prominent, outwardly projecting ribs; and it typically has robust, accordion-like folds along its midsection's sulcus. These features likely contribute to the control of water movement within the shell.