Shell large, 85.2 mm in height, 90.6 mm in length and 78.1 mm in breadth, inflated, near quadrate, inequivalve, left valve larger than right one; anterior side rounded, posterior nearly truncated; umbonal part swollen, beak situated almost at dorsal centre, ligamental area short and broad, bent slightly inward; surface sculptured with 31 - 34 flat and wide radial ribs, radial ribs of left valve granulated, those of right smooth, and covered with a brown coarse epidermis.
Distribution: East and South China Seas; Indo-Western Pacific region.
Ecology: Found in shallow waters of subtidal zone.