Echiuroidea
Ech`i*u*roi"de*a\, n. pl. [NL., fr. echiurus, the name of one genus (Gr. ? an adder + ? tail) + -oid.] (Zo["o]l.) A division of Annelida which includes the genus Echiurus and allies. They are often classed among the Gephyrea, and called the armed Gephyreans.