Fig. 4. The shadow response of surface fish (A,C,E,G) and Pachón cavefish (B,D,F,H) after pinealectomy or removal of one or both bilateral eyes. The frames show merged images at 0.05 s intervals from 0 to 5.0 s after the assay chambers were shaded. A normal shadow response is observed in sham-operated surface fish and cavefish controls (A,B) and after removal of one (E,F) or both (G,H) bilateral eyes from surface fish or cavefish larvae. In contrast, the shadow response is absent in most surface fish or cavefish larvae after pinealectomy (C,D). Scale bar, 1 cm. Other details are the same as in Fig. 1.