This specimen is at Little Corona del Mar, Ca. Photo by Dave Cowles, March 2005. Note the Balanus glandula barnacle nearby and the tar-spot algae. This indivudual is likely keeping the rock area below it bare by grazing.
A very large Lottia instabilis found at Hobuck Beach, on the open coast near Neah Bay, WA. This shell was empty and washed up on the beach. (Photo by: Dave Cowles, July 2007)