Phylum Platyhelminthes Hyman, 1951
Bilateria with weakly multicellular epidermal cells, the cilia are being devoid of an accessory centriole at the basal body. The bilaterally symmetrical protonephridia provided with more than one terminal cell; terminal and canal cells biciliar, both cilia without accessory centriole and without an inner circle of 8 microvillar rods. Epidermal cells and other somatic cells do not undergo any mitosis.
Platyelmia Vogt, 1851
Platyelminthes Gegenbauer, 1859
Plathelminthes Schneider, 1873