Order ASPIDOSIPHONIFORMES
Introduction
After Edmonds (2000)
Members of the Aspidosiphoniformes are diagnosed by having an anterior trunk which has been modified to form a hardened anal shield or a calcareous knob or cone, and two retractor muscles which may fuse near their base and comprises only one family, Aspidosiphonidae.
General References
Edmonds, S.J. 2000. Phylum Sipuncula. pp. 375-400 in Beesley, P.L., Ross, G.J.B. & Glasby, C.J. (eds). Polychaetes & Allies: The Southern Synthesis. Fauna of Australia Vol. 4A Polychaeta, Myzostomida, Pogonophora, Echiura, Sipuncula. Melbourne : CSIRO Publishing Vol. 4 Part A xii 1-465 pp.