| Stylochoplana pusilla Bock, 1924 | 1938 | | | commonly found on the coasts of Japan. |
| Prosthiostomum auratum Kato, 1937 | 1938 or earlier | | | |
| Micaplana misae Kato, 1937 | 1936 | 20 m | | autumn of 1936 by dredging from a depth of about 20 meters off Susaki, Idu. |
| Discocelis japonica Yeri & Kaburaki, 1918 | 1944 or earlier | | | |
| Stylochus ijimai Yeri & Kaburaki, 1918 | 1944 or earlier | | | Susaki near Simoda. |
| Stylochus izuensis Kato, 1944 | Feb 20, 1937 | 18 m | | Off Susaki near Simoda, Izu. A single specimen was collected by dredge from a depth of 18 m. |
| Cryptocelis ijimai Bock, 1923 | 1944 or earlier | | | Susaki near Simoda. |
| Amemiyaia pacifica Kato, 1944 | 1944 or earlier | | | |
| Notoplana delicata (Yeri & Kaburaki, 1918) | 1944 or earlier | | | |
| Discoplana gigas Schmarda, 1859 | 1944 or earlier | | | |
| Discoplana takewakii Kato, 1935 | 1944 or earlier | | | |
| Planocera purpurea Yeri & Kaburaki, 1918 | 1944 or earlier | | | |
| Prosthiostomum vulgaris Kato, 1938 | 1944 or earlier | | | |
| Prosthiostomum komaii Kato, 1944 | 1944 or earlier | | | Susaki near Simoda. |
| Prosthiostomum suzakiensis Kato, 1944 | 1944 or earlier | | | Susaki near Simoda. |