The four classes of cnidarian include the following except

Explanation

Modern cnidarians are generally classified into four main classes: sessile Anthozoa (sea anemones, corals, sea pens); swimming Scyphozoa (jellyfish) and Cubozoa (box jellies); and Hydrozoa

Turbellaria are one of the traditional sub-divisions of the phylum Platyhelminthes (flatworms)

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