Hemichordata (Hemichordates)
Class: Enteropneusta
Order: [Unassigned]
Family: Ptychoderidae
| Scientific Name | Author/s | Common Name | Last Record | Distribution | Status | Taxon Profile |
| Balanoglossus gigas | (Müller in Spengel, 1893) | - | - | Brazil | Rediscovered | Access |
Family: Spengelidae
| Scientific Name | Author/s | Common Name | Last Record | Distribution | Status | Taxon Profile |
| Glandiceps abyssicola | Spengel, 1893 | - | - | Atlantic Ocean | Rediscovered | Access |