I want to know the answer to the following question:
What is movement by ripples called?
All the background I'm provided with is that "In species with incomplete septa or none, the blood circulates through the main body cavity without any kind of pump, and there is a wide range of locomotory techniques – some burrowing species turn their pharynges inside out to drag themselves through the sediment.". Is that enough to answer the question?
Answer: no