Fig. 7. (A) Side and (B) ventral view of a model of the midsection of the lateral flagellum of a P. argus antennule, which has been painted black so that the zig-zag arrangement of the aesthetascs can be easily seen. Lines labeled 1–3 indicate three locations where velocity transects were taken at right angles to the surface of the antennule flagellum, with corresponding velocity measurements shown in graph in C. In total, 20 transects were made at different locations through the aesthetasc array. All distances and velocities have been converted to those for a real antennule. A distance of 0 mm corresponds to the base of the aesthetascs next to the lateral flagellum of the antennule; 0.8 mm corresponds to the tips of the aesthetascs. High flow occurs both near the tips of the aesthetascs and at specific locations within the array where gaps in the zig-zag hair arrangement occur.