« Donax politus: Shell triangularly oblong, not very inequilateral, much compressed, with a greater convexity in the umbonal part, rather thick, opaque, lustrous. Sculpture, scarcely any other than a few slight and indistinct concentric lines, and occasional marks of growth which alone are perceptible by the naked eye. Colour chestnut blended with olive, beautifully marbled or necked with creamcolour and marked with a conspicuous longitudinal ray of the same tint, which proceeds from the beak and is obliquely curved towards the ventral margin on the anterior side. This ray becomes broader as it approaches the margin, being there of a considerable width in full-grown specimens. The beaks are usually violet or flamecolour, and variegated by a blotch of dusky purple under the ligament, and sometimes by a similar but fainter stain on the other side of the beak. The lines of growth are also distinguished by narrow bands of violet when that hue appears. Epidermis thin and smooth, olivaceous… » – J. G. Jeffreys: British conchology vol. II, London 1863.