| Discocelis japonica Yeri & Kaburaki, 1918 | 1944 or earlier | | | |
| Stylochus speciosus Kato, 1937 | 1944 or earlier | | | Sugasima, Sima, under stones between tidemarks. |
| Stylochoplana pusilla Bock, 1924 | 1944 or earlier | | | commonly found in the mantle cavity of Monodonta labio Linné, and rarely of Tegula exanthostigma (A. Adams), Thais tumulosa clavigera (Küster). |
| Notoplana delicata (Yeri & Kaburaki, 1918) | 1944 or earlier | | | |
| Hoploplana rubra Kato, 1944 | Jun 1935 | | | Sugasima, Sima. Two specimens collected from under-surface of stone in low tidemark. |
| Planocera multitentaculata Kato, 1940 | 1944 or earlier | | | Usually found together with Planocera reticulata. |
| Pseudostylochus elongatus Kato, 1937 | 1944 or earlier | | | Sugasima, Sima. |
| Thysanozoon brocchii (Risso, 1818) | 1944 or earlier | | | |
| Prosthiostomum vulgaris Kato, 1938 | 1944 or earlier | | | |