Crassinella lunulata (Conrad, 1834) - Lunate Crassinella
Trigonal, umbonal angle slightly hooked (observed from interior) and at ca. 90° angle, anterior margin more convex and slightly longer, compressed, solid, white to yellow-brown to dark brown, occasionally radially rayed, with ca. 15-17 coarse commarginal ridges varying from rounded to thin and erect, plus microstructure resembling snakeskin; interior white with brown staining or reflecting exterior colors, margin smooth. Massachusetts to Florida, Bermuda, Bahamas, West Indies, Gulf of Mexico, Caribbean Central America, South America (to Uruguay). Length 5 mm (to 9 mm). Compare Crassinella martinicensis, which has an unhooked umbonal angle.