echinocystoida

\\“+sə̇ˈstȯidə\ noun plural

Usage: capitalized

Etymology: New Latin, irregular from Echinocystites, fossil genus of Echinodermata (from echin- + -cystis + -ites -ite) + -oida

: an order of Silurian fossil echinoids having small irregular spheroidal or flattened tests