Fig. 1. Synthesis of thiotaurine in gill homogenates of (A) Calyptogena magnifica and (B) Bathymodiolus thermophilus, and (C) trophosome homogenates of Riftia pachyptila, incubated with various concentrations of sulphide (0.25, 0.5 and 1 mmol l^-1 Na₂S) and thiosulfate (1 mmol l^-1 Na₂S₂O₃). Values (µmol g^-1 dry mass) are means ± S.D. (C. magnifica, N=6; B. thermophilus, N=5; R. pachyptila, N=4). Asterisks designate significant differences from the controls (Student's t-test, ^*P0.05, ^**P0.005).