Featherlike ctenidium well extended from nuchal cavity to right of head.
Cilia on ctenidium create water current (blue arrows) into left of nuchal cavity, then between ctenidial filaments to oxygenate blood within them, and thence as exhalent current along pallial groove on each side of foot to exit at posterior of limpet.
Some blood passes in blood vessels (red arrows) through gaps between bundles of shell-muscle to peripheral efferent pallial vessel (where it probably gets oxygenated instead of in ctenidium) and thence through the nuchal cavity to the heart.