Strong shell up to 2.5cm in length. The colour is variable including white, yellow, cream, brown or purple in vaious patterns. The sculpture is very variable. Early in life there are no ribs but can develop up to thirty later on and can can also develop to different extents.
- Ventral half of the shell is semicircular
- The shell sculpture is generally smooth but can display radiating ribs
- Anterior ear is three times as long as posterior
Lives on sandy mud or gravel where it filter feeds phytoplankton.
FrequentDistributed from northern Norway to the Iberian Peninsula