data are presented in the figures individually or as means +1 standard error(SE).student's unpaired t-test was used to evaluate the significance of differences between mean values.Linear regression analysis was used to quantify the various SW media on branchial Na, K-ATPase ESA. Two-way analysis of variation(ANOVA, repeated measures) was used to determine:the significance of changes in branchial Na, K-ATPae ESA caused by acclimation of crabs for 14 day in the four SW media;and the significance of the relation between changes in branchial Na, K-ATPase ESA and in the osmotic gradient maintained across the body wall in the acclimation media. Fisher PLSD (pooled lowest significant difference) analysis was used to determine the significance of from crabs acclimated in the various media. P