Radula 267% length of shell. P. depressa probably has longest radula, relative to shell length, of any British mollusc; up to 270% (Fretter & Graham, 1962, p.172) . Length varies seasonally; shorter when wear of active feeding exceeds growth rate. Patella spp. wear out up to two rows of teeth per day (Sigel, 2008 ). Shell length 30 mm.  Llŷn, Wales. September 2015.

OTHER SPECIES ALBUMS
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