Starfish
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Starfish or sea stars are a class of marine invertebrates generally shaped like a star polygon. Starfish are also known as asteroids because they form the taxonomic class Asteroidea. About 1,900 speci
Luidia maculata, a seven armed starfish
Astropecten aranciacus ossicles
Pedicellariae and retracted papulae among the spines of Acanthaster planci
Pedicellaria and papulae of Asterias forbesi
Crinoid
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Crinoids are marine invertebrates that make up the class Crinoidea. Crinoids that remain attached to the sea floor by a stalk in their adult form are commonly called sea lilies, while the unstalked fo
Stalked crinoid drawn by Ernst Haeckel
Stem, theca and arms of a "true" (stalked) crinoid (family Isselicrinidae)
Oxycomanthus bennetti (comatulid)