1.Sodium. potassium and magnesium ion concentrations in
the blood of Ocypode were hypoionic (0 normal and concentrated sea
2. Over the entire salinity range tested calcium ion concentration was
found to remain fairly constant and hyperionic to all media.
3. The changes in haemolymph sodium concentration reflect the changes
in tQtal osmotic concentration.
4. Death from desiccation related directly to weight loss,indicatiogthaf
wa~er loss probably as circulatin& ha~molymph volume was the critical factor,
rather than ionic concentration.