Chthamalus sp. from 11/3 lab.
I found an interesting paper about how barnacles move and use their cirri. I’m on the fence about whether this barnacle’s cirral movement would be considered #3 or #4 from the descriptions below.
(1) testing, in which the valves hardly open and the cirri are not protruded.
(2) pumping, in which strong rhythmic movements of the operculum occur, but the cirri are protruded only slightly, and not extended.
(3) normal beat, a development of pumping, but with the cirri fully extended and withdrawn in rhythm with the opercular movements.
(4) fast beat, with less opercular movement, but strong and fast rhythmic cirral movements.
(5) extension, in which the cirri are held outside the shell for varying periods without rhythmic movements.