How do sea lilies differ from feather stars?

Both sea lilies and feather stars belong to the class Crinoidea within the phylum Echinodermata, but they differ primarily in their mobility and physical structure.12

• Sea Lilies: These animals are characterized by a stalk that fixes them permanently to the sea bottom. Their body, which is surmounted by frondlike tentacles, gives them a plant-like appearance. They are typically found in deep waters, where they feed on detritus.1
• Feather Stars: Unlike sea lilies, feather stars lack a stalk. This absence of a stalk allows them to move from place to place, making them capable of changing their location.1

While both groups share a similar internal skeleton composed of limy plates and possess branching feeding arms with small pinnules, the presence or absence of the stalk is the defining distinction between these two types of crinoids.12