Echiuroidea \Ech`i*u*roi"de*a\, n. pl. [NL., fr. echiurus, the
name of one genus (Gr. 'e`chis an adder + o'yra` 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}.
[1913 Webster]