A superb complete adult internal mould, fully developed on both sides, showing 5 whorls with strong dense ribbing. All the sutures including the last show well and the body chamber occupies 2/3 whorl and has a flared peristome on one side and the venter. The most evolute member of the Cardioceratidae, the outer whorl being almost serpenticone. From Jameson Land, E Greenland.
Size: 51 mm
Size: 51 mm