Assertion: extant echinoderm | /r/HasAspect | sea urchins
Facets:
Source sentences:
text: The extant echinoderms are divided into five clades including the Sea Lilies (Crinoidea), Starfish (Asteroidea), Brittle Stars (Ophiuroidea), Sea Urchins (Echinoidea), and Sea Cucumbers (Holothuroidea).