Fig. 3. Representative time course of I_sc* across split lamellae of posterior gills of C. granulatus, showing the effects of internal addition of 10 mmol l^-1 BaCl₂ (2) and 2 mmol l^-1 diphenylamine-2-carboxylate (4, DPC as free acid). At (1) BaCl₂ was added to the external bath as a control for diffusive movements of Ba²⁺ and Cl^-. At (3) dimethylsulfoxide, the primary solvent for DPC, was added to the internal solution. The vertical current deflections are due to 1 mV voltage pulses and reflect the uncorrected conductance across the preparation.