Fig. 9. (A) PIV measurements of water velocities relative to the aesthetascs of a dynamically scaled model of the lateral flagellum of the antennule of a P. argus during a flick downstroke (from right to left, details described in Fig. 5). The aesthetascs in this case point in the same direction as antennule motion, rather than being oriented 32° from the direction of the oncoming flow relative to the antennule (see Fig. 2). (B) Peak velocity along the mid-line of the aesthetasc array (transect shown in red) and the mean velocity. Mean velocity was computed as the area-averaged velocity for the 20 transects made through the array. Peak velocity was the maximum velocity measured at a given distance from the lateral flagellum along any of the transects.