| Nominal Species (n = 3) | Present allocation (n = 3) | Ref. |
|---|---|---|
| Protohydra caulleryi Dawydoff, 1930 | Protohydra caulleryi | 8278 |
| Protohydra leuckarti Greeff, 1870 | Protohydra leuckarti | 19 |
| Sympagohydra tuuli Piraino, Bluhm, Gradinger & Boero, 2008 | Sympagohydra tuuli | 80485 |