Shell short, stoutish, slightly curved, pale apple-green, which is so alternated in ill-defined zones of translucency and opacity as to give on a fresh specimen the effect of the silk known as moire antique, though the sculpture is not mod¬ified in these zones; sculpture of very fine sharp slightly elevated incremental lines, visible only in the interspaces between the longitudinal threads; the latter are even, squarish, rather flattened threads, with subequal channelled interspaces, about six threads to the millimeter of circumference; close to the aperture they become faint, and posteriorly every alternate thread is weaker until it disappears. Both orifices are circular, the anal one has the upper, and to a less degree the lower edge gently concavely waved, but without a slit. Generally this end is decollate and circular. Lon. of shell, 17.0; height of arch from chord, 2.4; diameter of aperture, 2.12; of anal orifice, 0.5 mm.

Off the Carolina coast, in 22 to 52 fms., sand, temperature 67° to 78°, at U. S. Fish Commission Stations 2598, 2608, and 2612. Station 2405, in the Gulf of Mexico between the Mississippi delta and Cedar Keys, Florida, in 30 fms., sand.