Samples from the Ross Sea (Antarctic) contained four prostomia (“probosces”) of Echiurida which belong to two new species:
1. The prostomium of Binoraphorus geminolobotus n. g. n. sp. shows a symmetrical arrangement of double organs. This unique dual prostomium is externally marked by two mouth openings, by a ventromedian ridge and by a bilobed distal end.
2. The typical echiurid prostomium of Echiurus torulobotus n. sp. possesses a proximal swelling similar to that of Echiurus echiurus. It must be stated, however, that the latter is without exception a boreal-arctic form, and the present prostomia belong therefore to a geographically separated species.