Cyanonemertes elegans, new genus and species, is described as a member of the order Hoplonemertea, suborder Monostilifera. In general morphology, it appears to be most closely related to the genus Amphiporus (family Amphiporidae). The most important features justifying the new taxon are: 1) cephalic muscle layer with anteriorly divided longitudinal musculature, 2) diagonal muscles of non-fasciated, lattice type, 3) retractor muscles derived from the outer portion of the longitudinal musculature, 4) cephalic blood system with extra-cerebral vessels, 5) rhynchocoel extending almost to posterior end of body, 6) rhynchocoel wall bilayered, 7) neurochord cells absent, 8) rhynchodeum with an outer layer of longitudinal muscle, 9) central stylet-basis complex present, and 10) proboscis sheath with thick muscular plate.