Fig. 1. Diagrams of experimental setups. (A) Cross section of the dish used in behavioural experiments. Tadpoles could be unattached on the bottom of the dish, or attached by their cement gland mucus to a piece of wire, which was fixed to the side of the dish. (B) Scale diagram of the Xenopus tadpole to show the location of strokes to the head and tail used in behavioural and electrophysiological experiments (shaded areas indicate region and arrows indicate direction). Scale bar, 1 mm. (C) Diagram of the head of the tadpole showing the mandibular nerve of the trigeminal ganglion innervating the cement gland. The site of the lesion is shown by a dotted line. (Modified from Roberts and Blight, 1975.) (D) Simulating cement gland attachment. The immobilised tadpole was pinned to a Sylgard block that was rotated so that the tadpole pointed downwards. A weight attached to the cement gland mucus was able to hang freely. An extracellular suction electrode on an intermyotomal cleft monitored fictive swimming activity from a motor nerve. Arrows show the direction of rotation of the block.