Polychaetes of 117 species or subspecies and two indeterminable species in 18 families from Sagami Bay and Sagami Sea are recorded from the collection made by the Emperor Showa, deposited at the Showa Memorial Institute. Eighteen families belonging to four orders are Chrysopetalidae, Aphroditidae, Pholoidae, Sigalionidae, Eulepethidae, Phyllodocidae, Glyceridae, Goniadidae, Sphaerodoridae, Hesionidae, Syllidae, Nereididae, Nephtyidae, Paralacydoniidae in Phyllodocida; Amphinomidae, Euphrosinidae in Amphinomida; Spintheridae in Spintherida and Onuphidae in Eunicida. Twenty-one new species are described as follows:
Aphrodita nipponensis,
Pontogenia dentata and
Pontogenia sagamiana in Aphroditidae,
Sthenelais brachiata and
Sthenelanella japonica in Sigalionidae,
Mystides japonica,
Nereiphylla crassa and
Paranaitis serrata in Phyllodocidae,
Glycera amadaiba in Glyceridae,
Goniada brunnea goronba and
Goniada sagamiana in Goniadidae,
Ephesiella oculata in Sphaerodoridae,
Odontosyllis trilineata,
Exogone exilis,
Eurysyllis japonicum,
Syllis exiliformis and
Trypanosyllis (Trypanobia) foliosa in Syllidae,
Pherecardia maculata in Amphinomidae,
Euphrosine polyclada and
Euphrosine ramosa in Euphrosinidae,
Spinther sagamiensis in Spintheridae. Four genera,
Sthenelanella in Sigalionidae,
Mystides in Phyllodocidae,
Wesenbergia in Hesionidae and
Eurysyllis in Syllidae, are reported for the first time from Japanese waters. Nine species,
Aphrodita goolmarris in Aphroditidae,
Eulalia ornata,
Sige falsa and
Paranaitis polynoides in Phyllodocidae,
Glycera lapidum in Glyceridae,
Wesenbergia problematica in Hesionidae,
Ceratonereis costae in Nereididae and
Notopygos gardineri and
Pareurythoe parvecarunculata in Amphinomidae, are newly added to the Japanese polychaetous fauna.