Taxonomy of some Galeommatoidea (Mollusca, Bivalvia) associated with deep-sea echinoids: A reassessment of the bivalve genera Axinodon Verrill & Bush, 1898 and Kelliola Dall, 1899 with descriptions of new genera Syssitomya gen. nov. and Ptilomyax gen. nov. Author Oliver, P. Graham text European Journal of Taxonomy 2012 2012-04-25 12 1 24 journal article 21841 10.5852/ejt.2012.12 5217c4a1-a0dd-478e-bd0c-95df35bad69b 2118-9773 3857751 098E15C8-27DB-46C7-8A15-6394EE854B64 Genus Axinodon Verrill & Bush, 1898 Type species Axinodon ellipticus Verrill & Bush, 1898 . Diagnosis (based on shell characters alone) Shell small, thin. Equivalve. Inequilateral, beaks behind the midline. Umbos prominent, beaks prosogyrate. Outline obliquely subcircular, distinctly expanded anteriorly. Sculpture of commarginal ridges. Hinge plate narrow, ligament deeply sunken on a groove running from under the beaks posteriorly. Right valve lacking any projecting teeth; left valve with a short, weak. marginal flange beneath the lunule. Isomyarian. Pallial line entire.