Echiura
English: Spoon worms.
Members: 140 species.
Habitat: marine; in burrows in sand and mud; in rock and coral crevices; mostly in shallow water, some in deep sea.
Zoology
Animals; similar in size and habit to sipunculans.
Taxonomy
Echiura are often considered to be a group of annelida. But they lack the segmented structure found in other members of that group, and so may also be treated as a separate phylum.
Phylogenetic analyses of DNA sequences place echiurans and pogonophorans within the Annelida.