Marine dwellers have the opposite problem, and need to conserve fresh water while expelling salt. Cephalopods pump seawater through their gills and use their kidneys to filter out fresh water from the ocean. Salts and waste water are channelled through the funnel.
^ to top
Need for speed
Even Cheap Cigarettes Outlet if they did initially evolve a mechanism for coping with freshwater, Norman says that as they needed to outswim increasingly fast fish predators, and to become supercharged top-order predators themselves, many functions were lost. This allowed others to develop to extremes.