Phorcus lineatus

Phorcus lineatus, common name the lined top shell, is a species of sea snail, a marine gastropod mollusk in the family Trochidae, the top snails. It is native to shores of the eastern North Atlantic Ocean.

Description
The size of the shell varies between 10 mm and 35 mm. The very thick and solid imperforate shell is subperforate in the young. It has a globose-conic shape. It is dull grayish, densely marked all over with very numerous fine flexuous or zigzag braided purplish-black lines. The spire is conic. The 6 to 7 whorls are convex. The apex is usually eroded and orange-colored. The body whorl is flattened around the superior portion. The base of the shell is eroded in front of the aperture. The aperture is oblique. The columella is short, obtusely subdentate near the base, spreading at the insertion into a heavy callous, which covers the umbilicus.

This species is similar to Phorcus turbinatus in form, but usually has the outlines of the spire more convex. The columella projection or tooth is nearer the base than in the Phorcus turbinatus, and the diverse color patterns will serve to further distinguish the two species.

Distribution
This species occurs in the following locations:
 * European waters (ERMS scope)
 * Portuguese Exclusive Economic Zone
 * Spanish Exclusive Economic Zone
 * United Kingdom Exclusive Economic Zone
 * Wimereux
 * Atlantic Ocean off Mauritania.