Shell ovoid, oblong, not tapering anteriorly, smooth and glossy. Aperture surrounded by a thickened, porcellaneous callus and extending along the whole length of the shell. Outer lip curled in and with 15-16 denticles on the inner side, columellar edge with a row of teeth more closely set than those of the outer lip, gradually larger and more oblique towards the anterior end.
shell bluish green with tiny brown specks all over and a few large, blurry brown blotches on the dorsal side; callus around the aperture, cream with scattered dark brown spots, both ends of the aperture with paired brown/purplish blotches. The subspecies notata is distinguished by the bright red color of the mantle lobes of the animal, contrasting with the dark brownish color in P. gracilis gracilis (see Doneddu and Manunza, 1994).
common size :
The rather cylindrical outline, spotted pattern around the aperture, and bluish pattern on the dorsal surface of the shell are distinctive characteristics which make unlikely a confusion with any native species. The shell of Erronea caurica, once reported in the Mediterranean but which we reject as such, is similar but larger, has few and less distinct spots on the sides, and has no purple marks around the canal.
BIOLOGY / ECOLOGY
on shallow sublittoral rocky bottoms.