The planarian flatworm like other species in this phylum do not contain a circulatory system.
Because the planarian does not contain a circulatory system their body passes oxygen and
certain important nutrients through diffusion. They transport essential nutrients, gases and
oxygen through diffusion.
Because the planarian does not contain a circulatory system their body passes oxygen and
certain important nutrients through diffusion. They transport essential nutrients, gases and
oxygen through diffusion.