Shell-bearing Mollusca (Bivalvia and Gastropoda) from submarine caves in Hong Kong Author Lam, Katherine Author Morton, Brian Author Leung, K. F. text Journal of Natural History 2008 2008-03-31 42 9 - 12 927 952 http://dx.doi.org/10.1080/00222930701862674 journal article 10.1080/00222930701862674 1464-5262 5225019 Isognomon legumen ( Gmelin, 1791: 3339 ) ( Figure 2L ) Description Shell length variable but to, 20 mm , irregularly subquadrate, elongate posteroventrally. Both valves quite flat. Umbo situated antero-dorsally, pointed forward. Several ligament pits along the long, straight hinge line. Shell exterior yellowish white with micaceous growth lamellae. Type locality ‘‘ad insulas Nicobaricas’’ ( Nicobar Islands , Indian Ocean). Distribution Indo-Pacific from the Philippines to Japan , Hawaii and the Red Sea. Intertidal to 20 m subtidal, attached to the undersides of boulders, in mussel aggregations, within coral heads and on pilings ( Scott 2003 ).