Onuphid polychaetes belonging to the genus
Onuphis collected from various areas around Japan and adjacent seas were examined. Sixteen species including 6 species new to science and 1 indeterminated species are described. Zoogeographical consideration for the
Onuphis species described above and 7 more species which were collected from various Japanese coasts and the adjacent seas and were reported by other authors elsewhere clearly shows that (1) each
Onuphis species tends to occur in a somewhat limited area, (2) the faunal elements are highly segregated between the northeastern and the southwestern parts around Japan and (3) quite a few species occur in single restricted collecting sites.