This shell looks like a cross between Lottia digitalis and Lottia pelta.
The apex is closer to the anterior than in L. pelta, but not so forward
as L. digitalis). The shell margin and markings look more like L. pelta,
the margin being either solid dark or with dark spots. The grayish exterior is often
pitted by the fungus Didymella conchae. This species may have low radial ribs,
bot not the strong ones of L. digitalis. The interior of the
shell is white or faintly bluish and does not have an apical blotch.
Vancouver Island, BC to Cabo San Lucas, Baja Mexico.
On protected slopes and surfaces. Mid-tide level on rocky shores.
Can be confused with Lottia digitalis and Lottia pelta.