Fig. 2. Weaving pattern of N. succinea upon encountering a trail of glutathione at an oblique angle. The concentration of glutathione in the syringe was 10^–5 mol l^–1, yielding a trail (gray streak) concentration somewhat less than 10^–6 mol l^–1. (A–F) Successive images of the path swum by the animal (indicated by the broken line in F). The total time between images A and F was 3 s. The 10 cm calibration applies to all parts.