G. S. Cater (1940) wrote that body fiuid fiow of invertebrates is not evolutional: a definitive and mutual1y exclusive morphological classification of transport mechanisms is impossible. However，concerning our comparative study，the body fiuid fiow of Ameba，Olynthus，Scyphomeduse，Fasciola hepatica Linne，Irematoda nemertini，Nereis japonica，Lingula anatina Lam，Graptopsaltria nigro fuscata，Sesama haematocheir，Ostea and Octopoda is understood in a concept of evolution.