Children (7 direct children, 287 direct and indirect children):
Echiuroidea
(tree size 270)
Echiuroinea
Bonelliida
(tree size 3)
Bonellida
Binoraphorus
(tree size 1)
Sactosoma
(tree size 1)
Heteromyota
(tree size 4)
Xenopneusta
Coprinoscolex
(tree size 1)