Kellia suborbicularis

(Montagu, 1803)

Description (shell):
Shell tumid, umbones just in front of midline. Broadly oval, almost circular. Sculpture of fine concentric lines, growth stages distinct. Lunule broad and shallow, escutcheon scarcely discernible. Right valve with a single cardinal tooth below beak of umbo, and single posterior lateral; left valve with two cardinal teeth below beak, and single posterior lateral. Small external ligament visible posterior to beaks; in each valve position of internal ligament is marked by embayment in hinge line posterior to cardinal tooth/teeth. Pallial line broad, ill-defined, adductor scars about equal, not distinct (K. suborbicularis-drawing).

Up to 10 mm long.

White, with pale horn or yellowish periostracum. Inside of shell white or translucent.

Nearly transparent. The mantle extends considerably beyond the shell margin, and its edges are united all round. There is a large opening on the lower margin to allow passage for the strap-shaped foot; it is greatly extended in front to form an incurrent tube, and a small opening behind serves as an excurrent siphon. The animal moves freely by means of its foot, and attaches itself by an almost invisible thread.

Distributed from the lower shore to at least 100 m; occurs in holes and crevices, within old shells, barnacle tests, etc. Most frequent on southern and western shores.

Distributed from Norway south to the Mediterranean and West Africa (Distr. K. suborbicularis).