Trichoplax Adhaerens

a primitive multicellular marine animal of the group Phagocytellozoa. The leaflike body measures approximately 3 mm in length and consists of an external layer of cells with flagella and internal parenchyma formed of amoeboid cells. The organism reproduces both sexually and asexually. It is similar in structure to a phagocytella, which was considered the common ancestor of all multicellular animals by E. Metchnikoff.