“Genus ARTHRITICA Finlay, 1927
Type (OD) Kellia bifurca Webster, 1908
Shell small, quadrately-ovate, with an external ligament and an internal resilium. Surface smooth or with minute concentric wrinkles. Hinge with a small cardinal and two laterals in each valve. A feature of the type of the genus, developed only in the adult, is the presence of two callused limy patches, developed internally on the inner side of the adductor scars. The genus seems to be peculiar to New Zealand, where it ranges from the Otaian lower Miocene to Recent. Two of the species are commensal, but the type species appears to be free living.
(Powell, 1979: 391)
