“Notolepton sublaevigatum, n.sp. (Plate XLVII, fig. 7).
Shell small, thin, pellucid white, ovate, broader than high, very little inflated. Beaks small but prominent, inclined forwards. Anterior end slightly shorter than posterior end. Anterior end a trifle more narrowly rounded than posterior end, both broadly and evenly arcuate. Surface polished, showing very faint concentric growth lines but no true sculpture. Hinge typical. Right valve with a large elongate-triangular cardinal at the lower anterior part of the hinge plate, and a long narrow lamella above it, which is hooked downward at its inner extremity; behind the centrally placed resilifer there are two long narrow diverging lamellae. Left valve with an anterior hooked cardinal and a long medially thickened posterior lamella. Interior and valve margins smooth.
Length 2.8 mm.; height 2.3 mm.; thickness (one valve) 0.6 mm. (Holotype)
Habitat: Off Three Kings Islands, St. 933, 260 m.
This species differs from the genotype in being proportionately broader, less inflated, and in having the outer surface smooth except for microscopic growth lines. In antipoda there is a regular concentric sculpture of sharp closely spaced ridges.”
(Powell, 1937: 171-172)
