How does the movement of planaria compare to the movement of earthworms?

Planaria and earthworms exhibit different modes of movement due to their distinct body structures. Planaria, which are flatworms, move using cilia on their ventral surface and muscular contractions, allowing them to glide smoothly over surfaces and navigate through water. In contrast, earthworms employ a peristaltic motion, contracting and relaxing their segmented muscles along with the aid of bristles called setae to anchor themselves while burrowing through soil. This difference in movement reflects their adaptations to their respective environments: aquatic versus terrestrial.