Ennucula pachydonta Prashad, 1932 Shell small, 7.7 mm in length, 5.6 mm in height, solid, thick, rather inflate; umbo tumid, slightly in- clined posteriorly; surface covered with thin yellowish periostracum; hinge plate very thick, with 10 13 stout teeth on the anterior and 5-6 stout teeth on the posterior; chondrophore short, oblique, and directed forwards; interior pearly; inner margin smooth, not crenulated. Distribution: South China Sea; Indonesian Waters. Ecology: Known records range from 835-1 100 m.