Planarian Cardiovascular System:
The planarian, also known as the Planariidea is one of many flatworms in the Platyhelminthes phylum. It is also one of many non-parasitic flatworms of the Turbellaria class. Planarians are common in many parts of the world and they live in both fresh water and sea water. These animals do not obtain a cardiovascular system, so their body passes oxygen and certain nutrients through diffusion. Since they have no cardiovascular system most of the bodily needs for the planarians are passed throught the body by diffusion. |