Littorina nigrolineata

Gray J.E., 1839

Description (shell):
Shell solid, with well-developed spire of five or six moderately tumid whorls; last whorl comprises >75 % of shell height. Sculpture of irregular prosocline growth lines and strap-like spiral striae; a shallow central groove on striae of last whorl. Outer lip meets last whorl almost at right angles, margin slightly crenulate, internally thickening rapidly towards throat; inner lip reflected over columella region, extending to meet outer lip adapically as a glaze on last whorl. No umbilicus or umbilical groove (L. nigrolineata-drawing).

Up to 30 x 27 mm, commonly 20 x 18 mm.

Whitish, yellow or deep orange-red, often with dark brown pigmentation in grooves between spiral striae; peristome white, throat brown.

Body similar to Littorina littorea , penis with very short tip, close to which are 12 large glands. Female oviparous, ovipositor conspicuous below right eye. A pale streak extends diagonally from right to left across floor of mantle and through the penis/ovipositor.

Among weeds and stones; higher on exposed shores (barnacle/Fucus spiralis zone), extending down to Ascophyllum belt in sheltered areas.

Distribution imperfectly known (Distr. L. nigrolineata).