Shell large, up to 93.4 mm. (3,75 inches) in length, solid, very depressed, elongate-ovate, gradually narrowed in front, apex varying between subcentral and the anterior third. Sculpture consisting of from 9 to 11 broad radial folds, that give a prominently lobed outline to the margin. The whole surface is crowded with narrow rounded radials that are rendered scabrous by concentric growth lines. Colour of exterior greyish to pale orange, with maroon to dark purplish-brown stripes in the interspaces of the radial folds. Interior porcellanous-white, the spatula clouded here and there with cinnamon-brown. Margin of shell with a narrow, semitransparent amber-coloured border, showing brownish maculations corresponding to the external pattern.

This shell is extremely depressed, especially in its juvenile form, and at all stages of growth the prominent marginal lobes are a characteristic. Also, it attains a very much larger adult size than any other form of Scutellastra flexuosa.

Japan, Amami Islands and Ryukyu Islands.