Fig. 5. Mantle diameter, funnel diameter and vertical fin motion (relative to the point where the fin connects to the mantle) of a Lolliguncula brevis (7.3 cm in dorsal mantle length, DML) swimming (A) tail-first and (B) arms-first at 9 cm s^–1 against a steady flow in a flume. For each swimming orientation, 60 frames were analyzed to generate the traces.