Our studies were not designed to measure the hemolymph volume. We have , nevertheless, estimated this parameter and found it to be almost twice as large in EA lodsters compared to controls. However, an important caveat must be made. The value for controls is about 10% higher than that obtained by burger and Smythe in a very careful study. It is possible that age could be a contributing factor : their animals were adults that weighed approximately 500 g, ours were juveniles that weighed about 1% of that mass. Another pssibility concerns the 3-hr period that elapsed between injection of PEG and sampling. This period ensured that the radiolabel was equilibrated with the extracellular space of the muscle and hepatopancreas. During this period the C-PEG might penetrate spaces that permit only slow passage such as antennae, pleopods, and soon. Kinetic studies could test this possibility. We note that circulation time for the bulk hemolymph volume(turnover) is less than 10 min in adults . while we recognize the uncertainty in the absolute values obtained for hemolymph volume, the comparatively much larger value for EA animals appears valid and is clearly consistent with all other data presented here.