Definition of Blastoidea
: a class, formerly considered a division of Crinoidea, of extinct Paleozoic short-stemmed or stemless pelmatozoan echinoderms shaped somewhat like a flower bud and having five ambulacral areas with slender appendages along their margins and flattened tubes along their internal surface
blastoideanadjective or noun
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Origin and Etymology of blastoidea
New Latin, from blast- + -oidea
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