(Downloading may take up to 30 seconds.
If the slide opens in your browser, select File -> Save As to save it.)
Click on image to view larger version.

Fig. 2. Top views of a swimming frog during two successive stages of the kick
cycle, illustrating the absence of assumed propulsion enhancement mechanisms.
(A) Leg extension phase, showing rearward-directed flow around the webbed feet
without mutual interference, indicated by the forward-directed flow inbetween
(colour indicates flow magnitude, red=vmax
0.66 m
s1; blue
0 m s1). (B) Just after
completion of the extension phase showing two separate vortex rings, one from
each leg (colour indicates vorticity ranging from 0.15
s1=blue to 0.15 s1=red).