Found on seaweed at low tide on Hebrides, have only seen the empty shells before so was v happy to see one on the move!
No interactions present.
I have agreed Gina
This is certainly a Flat Periwinkle but (others might ask) it is obtusata or fabalis?
DO look at this http://www.ispotnature.org/node/437146 and read the comments.
THREE MARINE PROJECTS
Lat/Lng: 56.491, -6.849
OS grid ref: NM016437
Found on seaweed at low tide