| Name | Children | Media (from resource) | Traits |
|---|---|---|---|
| Akentrogonida | 0 | 0 | 3 |
| Alaria fistulosa | 0 | 0 | 2 |
| Alciopidae | 0 | 0 | 3 |
| Alentiana aurantiaca (Verrill 1885) | 0 | 0 | 2 |
| Alexandrella schellenbergi (Holman & Watling 1983) | 0 | 0 | 1 |
| Alvinellidae | 0 | 0 | 3 |
| Amakusaplana acroporae Rawlinson, Gillis, Billings & Borneman 2011 | 0 | 0 | 1 |
| Amnicolidae | 0 | 0 | 1 |
| Ampelisca Krøyer 1842 | 0 | 0 | 4 |
| Ampelisca richardsoni Karaman 1975 | 0 | 0 | 4 |
| Ampharetidae | 0 | 0 | 3 |
| Amphibolis antarctica (Labill.) Asch. | 0 | 0 | 3 |
| Amphibolis griffithii (J. M. Black) Hartog | 0 | 0 | 3 |
| Amphinomidae | 0 | 0 | 3 |
| Amphitrite ornata (Leidy 1855) | 0 | 0 | 10 |
