© J.C.A. Craik. The sequence of rapid ‘parasol’ swimming movements lasts about a second. With slight intervening pauses, there are about 45 strokes per minute (Morton & Holme, 1955, p. 105).
A: start of upstroke; parapodia move from contact with body to form a skirt with hem firmly flared out and up.
B: parapodia spreading out and up; animal loses some height during upstroke.
C: parapodia fully spread with edges flexed up at top of upstroke.
D: rapid downstroke of parapodia pushes animal up further than it dropped during upstroke; results in bobbing motion.
E: at the end of the downstroke, the parapodia are wrapped tightly around the animal. (Yellow faeces adhering to posterior in image.)
In soakaway pond of marine aquarium, Oban, Scotland. April 2010.

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