Fig. 2. (A) A plot of particle speeds at the canopy edge in the colony shown in Fig. 1D–F. Triangles indicate center positions of zooids at the canopy edge: zooid columns that formed part of the chimney after 4 days (filled triangles) and zooid columns that did not form a chimney (open triangles). (B) Mean particle speed (± S.D.) in each zooid column of the colony in A: chimney zooid columns (filled triangles) and non-chimney zooid columns (open triangles). (C) Box-plot of median excurrent flow speed in regions that subsequently gave rise to chimneys versus regions that did not: one chimney formed in each colony (N=7 colonies). Plot shows median, 1st and 3rd quartile, 1st and 9th decile, and minimum and maximum values.