Fig. 3. The effect of methacholine (10 mg kg^-1 and 1 mg kg^-1) on Na⁺ secretion rate by the salt glands of hatchling leatherback turtles Dermochelys coriacea. We stimulated hatchlings to secrete by injection of 27 mmol NaCl kg^-1 and measured secretory rate before and after injection of methacholine (N=6 for both groups). Data points show mean secretion rate ±1 S.E.M.