| Name | Children | Media (from resource) | Traits |
|---|---|---|---|
| Ophiuroidea Gray 1840 (brittle stars and basket stars) | 0 | 0 | 2 |
| Orthonectida (orthonectids) | 0 | 0 | 2 |
| Ostracoda Latreille 1802 (ostracodes) | 0 | 0 | 2 |
| Pararotatoria | 0 | 0 | 1 |
| Phoronida (horseshoe worms) | 0 | 0 | 2 |
| Phylactolaemata | 0 | 0 | 3 |
| Placozoa (placozoans) | 0 | 0 | 2 |
| Platyhelminthes (flatworms) | 0 | 0 | 2 |
| Polychaeta | 0 | 0 | 2 |
| Polyplacophora Gray 1821 (chitons) | 0 | 0 | 2 |
| Priapulida (penis worms) | 0 | 0 | 2 |
| Pterobranchia Lankester 1877 | 0 | 0 | 3 |
| Remipedia (remipedes) | 0 | 0 | 1 |
| Rhombozoa van Beneden | 0 | 0 | 3 |
| Scaphopoda Bronn 1862 (tusk shells) | 0 | 0 | 2 |
