Fig. 2. Veil protrusion and retraction are primarily filopodia associated. (A) Time-lapse merges illustrate veil categories. In this and all succeeding figures, protruding and retracting regions are indicated by red and cyan, respectively, by merging the later time point (red channel) with the earlier time point (blue and green channels). (a,b) Filopodia-associated protrusion – protrusion between two established filopodia. Veil edges can be convex (a) or concave (b). (c) Filopodia-independent protrusion – veil protrusion not connected to established filopodia. (d) Filopodia-associated retraction – retraction between two filopodia, retaining direct connection throughout retraction. (e, arrowhead) Filopodia-independent retraction is seen less than 3% of the time. (e, asterisk) Single filopodium-associated protrusion – protrusion along a single filopodium. (f, asterisk) Veil protrusion arising on a filopodium shaft. (B) Tabulation of frequency and width of veils in each category.