| Family | Common Name | Selected Genus and Species | Image |
|---|---|---|---|
| Agnathiellidae | Marine Worm | Agnathiella beckeri | |
| Austrognathiidae | Marine Worm | Austrognathia microconulifera | |
| Clausognathiidae | Marine Worm | Clausognathia suicauda | |
| Gnathostomariidae | Marine Worm | Gnathostomaria lutheri | |
| Gnathostomulidae | Marine Worm | Gnathostomula paradoxa | |
| Mesognathariidae | Marine Worm | Tenuignathia rikera | |
| Onychognathiidae | Marine Worm | Onychognathia rhombocephala | |
| Paucidentulidae | Marine Worm | Paucidentula anonyma | |
| Problognathiidae | Marine Worm | Problognathia minima | |
| Rastrognathiidae | Marine Worm | Rastrognathia macrostoma | |
| Family | Common Name | Selected Genus and Species | Image |
|---|---|---|---|
| Haplognathiidae | Marine Worm | Haplognathia simplex |  |
| Pterognathiidae | Marine Worm | Cosmognathia manubrium |  |