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Linné, 1758

Description (shell):
Shell solid, equivalve and inequilateral, beaks are in front of the midline. Approximately circular in outline, with a slight truncation on the posterior margin below the escutcheon. Ligament extending almost half-way to the posterior margin. Lunule is well defined, heart-shaped, light brown with very fine radiating ridges. Escutcheon is extensive in the left valve, semi-elliptical, with fine radiating ridges and transverse brown stripes; it is less well developed in the right valve where it may be encroached upon by the main shell sculpture and reduced to a border of fine radial ridges near the margin. Shell sculpture of prominent concentric ridges interspersed with small ridges; between the ridges and troughs there are fine concentric striae. Growth stages are not clear. There are three cardinal teeth in each valve. In front of the lower end of the anterior cardinal tooth of the left valve is a small tubercle, this is the anterior lateral tooth, which fits into a depression in the right valve. Pallial sinus is small, triangular. Inner margins of the valves are crenulate except below the escutcheon.

Size:
Up to 51 mm in diameter.

Colour:
Dirty white to pale fawn in colour, sometimes with red-brown rays. Interior of shell white. Periostracum a rich chestnut-brown (V. casina-drawing).

Animal:
The foot is large and tongue-shaped, adapted in burrowing. The siphons are unequal, cylindrical, relatively short and united, save at the tips.

Habitat:
A shallow burrower in bottoms of sand, muddy sand, gravel and shell gravel between 7-183 m.

Distribution:
Common in the North Sea (Distr. V. casina). It has a wide distribution from the south of Norway to the Iberian Peninsula, the Mediterranean, the Atlantic coast of Morocco, the Canary Isles, Senegal and Dahomey.

Venus casina