Fig. 3. Vorticity contour fields around and in the wake of the spotted boxfish (upper row), scrawled cowfish (middle row) and buffalo trunkfish (bottom row) models positioned at a pitch angle of -10°. The data are viewed in transverse planes at various locations along the body and in the wake. Each plot is the mean result of 30 image pairs (1 representative trial). From left to right, the locations, which are highlighted in the upper corner of figures, are: eye ridge, maximum girth, midpoint between maximum girth and posterior edge of the carapace, posterior edge of the carapace, caudal peduncle, and wake. The shadows on the sides of or beneath models represent areas that were shielded from laser light. White dots in scrawled cowfish and buffalo trunkfish figures are the tips of the ventral keels extensions. Mean circulation magnitude and mean peak vorticity magnitude for a dorsal vortex (_D and P_D, respectively) and a ventral vortex (_V and P_V, respectively) are included beneath the vorticity contour plots. In the scrawled cowfish, mean circulation magnitude and mean peak vorticity magnitude for a lateral vortex (_L and P_L, respectively) also are included. In the wake, dorsal and ventral distinctions are not necessary for the spotted boxfish and buffalo trunkfish since ventral and dorsal vortices merge.