Fig. 10. Side view (A), overhead view (B) and rear view (C) of excursion during the shallowing phase in one trajectory. The midpoint is at the center of each figure. The beginning of the sequence is indicated with gray circles. The first undulatory cycle is represented by thick lines. Missing data are represented by dashes. For most of the sequence, the head is roughly vertically aligned and about 20% SVL forward of the midpoint. The vent begins slightly lower than midpoint and is moved downward and forward in the second undulatory cycle. The head and vent move side-to-side in phase, with the head using a smaller amplitude than the vent. (M=26 g, SVL=62 cm.)