(Linné, 1767)
Description (shell):
Elongate oval, two to two and a half times long as wide. Only moderately arched, with rounded keel and small beaks. Sculpture of delicate growth lines and fine granulation. Head valve with up to 15 notches in anterior ventral margin; intermediate valves with a single notch on each side, articulamentum projecting along whole of anterior border of valve. Girdle relatively narrow, covered with densely packed, overlapping, rectangular granules, fringed with fine spines (I. albus-detail).
Size:
Up to 9 mm long.
Colour:
Shell valves unicolorous, off-white to yellowish.
Distribution:
Predominantly northern distribution. Not common (Distr. I. albus).