It can be divided into four parts: 1) a head, formed by a dorsally positioned prostomium that is fused to the peristomium, sometimes with a flattened cephalic plate; 2) a thorax, formed by the first four chaetigers (i.e. chaetae-bearing segments), usually with strong spines; 3) an abdomen, with several longer chaetigers that are often followed by a number of achaetous (i.e. without chaetae) segments; 4) a posterior end, with a pygidium that contains the anus.

Another species, Praxillura maculata, bears stiff particle-collecting spikes attached to the tube's end to collect algae and organic particles and transport them to the gut.

Some species spawn their gametes into seawater, where fertilization occurs; others may incubate eggs in the tube or directly until the development of larvae.

[2] They are capable of both anterior and posterior regeneration after suffering damage due to their fragile and easily fragmented bodies, and at least one species that reproduces asexually has been described.

[2] Maldanidae and Arenicolidae are united by the clade Maldanomorpha inside of Capitellida, an order of polychaetes in the phylum Annelida.

[4] Rhodininae Lumbriclymeninae Notoproctinae 'Euclymeninae' 'Euclymeninae' Nicomachinae 'Euclymeninae' Maldaninae The complete classification of bamboo worms accounts for 6 subfamilies, 38 genera and around 261 species.