Question: do rotifers have a coelom?
Answer: Roundworms (Nematoda) and rotifers (Rotifera) have a body cavity (coelom) where organs are found and that can serve as a hydrostatic skeleton. Their coelom is called a pseudocoelom because it is not completely lined by mesoderm. ... They have a true coelom that is completely lined by the mesoderm layer.