| Gaussia Wolfenden, 1905 |
| Gaussia princeps (T. Scott, 1894) |
| Metridia Boeck, 1865 |
| Metridia brevicauda Giesbrecht, 1889 |
| Metridia curticauda Giesbrecht, 1889 |
| Metridia pacifica Brodsky, 1950 |
| Metridia princeps Giesbrecht, 1889 |
| Metridinidae Sars, 1902 |
| Pleuromamma Giesbrecht, 1898 |
| Pleuromamma abdominalis (Lubbock, 1856) |
| Pleuromamma borealis (Dahl, 1893) |
| Pleuromamma gracilis (Claus, 1863) |
| Pleuromamma piseki Farran, 1929 |
| Pleuromamma quadrungulata (Dahl, 1893) |
| Pleuromamma xiphias Giesbrecht, 1889 |