| Name | Children | Media (from resource) | Traits |
|---|---|---|---|
| Abra Lamarck 1818 | 1 | 0 | 0 |
| Abra weberi Prashad 1932 | 0 | 0 | 1 |
| Abrina | 1 | 0 | 0 |
| Abra sibogai Prashad 1932 | 0 | 0 | 1 |
| Acanthaceae (acanthus family) | 1 | 0 | 0 |
| Acanthastrea Milne Edwards & Haime 1848 | 1 | 0 | 0 |
| Acanthastrea hemprichii (Ehrenberg 1834) (starry cup coral) | 0 | 0 | 1 |
| Acanthella Schmidt 1862 | 1 | 0 | 0 |
| Acanthella cavernosa Dendy 1922 | 0 | 0 | 1 |
| Acanthochitona Gray 1821 | 1 | 0 | 0 |
| Acanthochitona biformis (Nierstrasz 1905) | 0 | 0 | 1 |
| Acanthochitonidae Pilsbry 1893 (black chitons) | 1 | 0 | 0 |
| Acanthogorgia Gray 1857 (Yellow and purple spiny fan coral) | 3 | 0 | 0 |
| Acanthogorgia flabellum Hickson 1905 | 0 | 0 | 1 |
| Acanthogorgia paraspinosa (Stiasny 1947) | 0 | 0 | 1 |
