Two new western Atlantic species of Lucinidae, Lucina (Pleurolucina) hendersoni, new species, and Parvilucina (Bellucina) rehderi, new species, are described and figured. A new subgenus, Radiolucina (type-species, Phacoides amiantus Dall, 1901), of the genus Parvilucina is proposed. Certain aspects of the shell morphology of several groups of Lucinidae with similar hinge structure are compared. The nature of radial ornamentation in the subgenus Pleurolucina appears to differ significantly from that of Parvilucina or Radiolucina, suggesting the former should be considered distinct from the latter groups. Certain aspects of the shell morphology of Bellucina is demonstrated to be sufficiently distinct from that of species such as Parvilucina amiantus (Dall, 1901) to justify the establishment of a new subgenus, Radiolucina, for the latter. Several additional aspects of lucinid phylogeny are considered.
