Nemertellina minuta Friedrich, 1935, sensu Yamaoka, 1940, from Akkeshi Bay, Japan, is fully redescribed as a new species, Nemertellina yamaokai. The main characters distinguishing this taxon from N. minuta are the presence of two pairs of cephalic furrows and cephalic glands, and the absence of dorsoventral muscles from the intestinal region.
