Diagnosis: Shell large, thick, dark chestnut brown, depressed, with 3-4 whorls of which the last one is swollen and composes most of the shell. Narrow umbilicus, sometimes absent. Inner aperture margin curved outwards. Spiral punctuated lines on first whorl and embryonic shell, transverse growth lines on last whorl. Body dark brown. Wings fleshy. Small juveniles slightly lighter in color and occuring higher in the water column than adults. Protoconch I covered with pyramidal warts, protoconch II smooth. Shell height 11 mm.