Original: Crinoids, also known as sea lilies or feather-stars, are marine animals that make up the class Crinoidea of the echinoderms (phylum Echinodermata).
Simplified: Crinoids, also known as "sea lilies" or "feather-stars", are marine animals. They make up the class Crinoidea of the echinoderms (phylum Echinodermata).