I think that since it lives on the ocean floor, at the deepest of the ocean. So anyway, the fin on the Eurypterids is still necessary but not that much, since they live on the ocean floor. Their movements mostly on the ocean floor. So fin would not help them "stick" to the floor. Also there are still gravity acts on the Eurypterids and the feet would help them move faster. Hope this helps.
<span>Tetraphenylcyclopentadienone has five conjugated aromatic rings. Its structure suggests that it is highly conjugated. With this structure, it absorbs the energy from wavelengths of colors other than violet and reflects the energy from violet wavelengths.</span>
They are considered to have originated from cyanobacteria through endosymbiosis—when a eukaryotic cell engulfed a photosynthesizing cyanobacterium that became a permanent resident in the cell
