| Genus | Prostheceraeus |
| Species | moseleyi |
| Authority | Lang, 1884 |
| Family | Euryleptidae |
| Order | Polycladida |
| Location | Asturias, North of Spain |
| Length | about 25 mm (estimated) |
| PHOTO © Copyright | Ricardo Roberto Gernandez, Spain |
| Comments | P. moseleyi is attacking a couple of Clavelina lepadiformis, a quite common tunicate that obviously it is feeding on. |