Tellina donacina

(Linné, 1758)

Description (shell):
Shell is brittle, slightly inequivalve, right valve a little more convex than the left. Inequilateral, beaks in the posterior half, directed inwards and backwards. Oval in outline anteriorly but somewhat drawn out behind the beaks with both valves twisted slightly to the right near the posterior end. Ligament is a prominent green-brown arched band, set on a broad nymphal plate extending one-third the way from the beaks to the posterior margin. Sculpture of evenly spaced concentric ridges. Growth stages are clear. Right valve with two cardinal teeth, of which the posterior is bifid, and one anterior and one posterior lateral tooth. Left valve with two cardinals, of which the anterior is bifid, and single weak anterior and posterior laterals. The anterior lateral tooth of the right valve has an extended base which almost joins it to the anterior cardinal. Anterior adductor muscle scar is longer and thinner than the posterior. Cruciform muscle scars are obscure. Pallial sinus is very deep, a broad quadrate incision, its lower border confluent with the pallial line and its anterior point almost touching the anterior adductor scar. Margin is smooth (T. donacina-drawing).

Up to 25.4 mm in length.

Background colour of dirty white or pale yellow ornamented with pink rays radiating from the beaks; the rays increase in width and become broken up, they may coalesce near the ventral margin. Exceptionally, entirely white specimens may be found. Periostracum is faint, red-brown. Interior of shell is pearly white, sometimes with a mixture of reds and yellows, with the red rays of the exterior showing through.

A deep burrower in sand or mud. This habit has had effect in developing a powerful foot and in lengthening and separating the siphons. The lips are large, the gills are unequal in size and the mantle is fringed with tentacles. Colour white. (Tellina sp.-animal).

Around the British Isles inhabits coarse sand and shell-gravel, offshore to about 45 metres but may occasionally be collected between tide-marks.

Distributed south to the Mediterranean, the Black Sea, along the Atlantic coast of Morocco and to Madeira and Ghana (Distr. T. donacina).