The great majority of these barancles are Chthamalus montagui (kite shape aperture). Some are C. stellatus (oval aperture). One dead barnacle at the centre may be Semibalanus balanoides with a diamond aperture. The picture was taken on a shore exposed to strong waves, as this is where Chthamalus spp. live on rocks or other hard surfaces and, when covered by the tide, feed by sieving seawater for zooplankton.