Shell wide, roundly turbinate, with a low spire. Sculptured with low. spiral lines which tend to disappear on the body-whorl. Colour bluish green,. longitudinally marked with white zigzag streaks. Covered with a brown epidermis. Umbilicus open, encircled with a white callus; mouth oblique; round operculum calcareous, solid white, smooth, with strong indefinite concentric ridges which make a thick convex central area. Size: 2 inches.

Shell medium-sized, adults reaching a diameter of about 60 mm; thick-shelled and solid; wider than tall (h/w=0.8-0.9). Apex yellowish to orange, usually eroded. Teleoconch of about 4 whorls, rounded. Spire low and domed. Sculpture more or less obsolete, consisting of low wide spiral ribs, usually more evident on the early whorls. Suture subcanaliculate. Columella smooth and evenly curved, columellar callus spreading around the umbilicus; aperture oval. Umbilicus wide open and deep. Basic color pale to darker green, with dark green to almost black wavy axial lines and flames. Operculum thick, oval, with a central hump encircled by a shallow channel; white.

Its peculiar shape, wavelike markings, and unusually large umbilicus, will suffice to identify the species.
The distinctive coloration and the construction of the operculum easily distinguish Turbo (Subninella) undulatus from Turbo (Ninella) torquatus which is often found in the same localities. Remarks: The shell is completely covered with a relatively thin brownish periostracum. Specimens from Western Australia sometimes tend to have more close-set and prominent spiral ribs than the ones from southern and southeastern Australia.

South Australia. A common species in the lower littoral of all rocky platforms.
Australia; New South Wales to Western Australia.