Genus Pillucina Pilsbry, 1921

Pillucina Pilsbry, 1921: 382 . Type species: Pillucina spaldingi Pilsbry, 1921 (junior subjective synonym of P. hawaiiensis (Smith, 1885)) (original designation).

Sydlorina Iredale, 1930: 390 . Type species: Sydlorina symbolica Iredale, 1930 (original designation).

DIAGNOSIS. — Shells small (H to 14 mm), inflated, sculpture of fine to broad radial ribs that often bifurcate, crossed by fine, low, commarginal lamellae. Sculpture usually more prominent on anterior and posterior parts of shell. Hinge with two cardinal teeth in left valve and a single cardinal tooth in right valve. Posterior lateral tooth present in both valves, anterior lateral tooth present or absent. Ligament internal, located on elongate resilifer that widens to the posterior.Anterior adductor muscle scar short and detached from pallial line for about 1/4-1/2 of length. Inner shell margin finely to coarsely crenulate.