Fig. 8. Carbonic anhydrase activity (µmol CO₂ mg protein^–1 min^–1) in anterior (G4, black bars) and posterior (G8, gray bars) of green crabs acclimated to 32 p.p.t. and transferred to 10 p.p.t. for 4 days. 32, 32 p.p.t. acclimated controls; 10-4days, intact crabs assayed after 4 days at 10 p.p.t.; 10 inj1x, intact crabs given a once daily injection of eyestalk extract from `donor' crabs acclimated to 32 p.p.t.; 10 inj2x, intact crabs given twice-daily injections of eyestalk extract from `donor' crabs acclimated to 32 p.p.t. Values are means ± s.e.m. (N=6-7). T=12°C. Asterisk indicates statistical difference at the 0.05 level of significance in G4 from 32 p.p.t. control. Different letters indicate statistical differences at P<0.05 in G8 across treatments.