| 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. |