MacGillivray, 1843
Description (shell):
Shell with short, fat spire, with five whorls and the protoconch; shiny and smooth. Whorls rounded, curving into sutures basally, with a few faint growth lines. Aperture oval, almost as long as last whorl, with flattened outer lip. Columellar tooth weakly developed; umbilicus small but distinct.
Size:
Up to 4.4 mm.
Colour:
White.
Habitat:
Hosts are many prosobranchs and several lamellibranchs, especially Mytilus edulis .
Distribution:
Common in the North Sea (Distr. O. scalaris).