Urchins (sea urchins) are also echinoderms, but they are not closely related to sea lilies.
Sea lilies are sessile animals, meaning that they are permanently attached to the sea floor. They have a stalk-like body with arms that extend out from the top.
Sea urchins, on the other hand, are mobile animals. They have a spherical or oval-shaped body with spines that extend out from all over their body.
Sea lilies do not get their get-up-and-go from urchins. In fact, sea lilies are not able to move around at all. They are sessile animals that are permanently attached to the sea floor.
