Bentharca Verrill and Bush, 1898. Type species (OD): Macrodon asperula Dall, 1881. Recent, West Indies. Shell compressed, ventrally recurved. Sculpture cancellate, with fine radial and commarginal lirae. Posterior teeth few, oblique; anterior teeth small, subvertical. Ventral byssal gape prominent. This genus, known from the early Miocene, is epifaunal and appears to be a recent invader of the deep sea, where it is usually associated with silicious sponges. Members of this genus are know to attach horizontally to the substratum. This habit results in substantial variability in outline. Numerous species have been proposed in this genus, although it appears that only a few variable, widely distributed species are involved. The genus has been associated with Acar, but its anatomy is closest to Bathyarca. The name is derived from the Greek benthos, deep, and the Latin arca, an ark shell; the gender is feminine.