(True Sea-cucumbers)
The Cucumariinae are characterised by having 10 tentacles.
Eight representatives are present in the North Sea:
- Cucumaria frondosa
- Leptopentacta elongata
- Ocnus lacteus
- Ocnus planci
- Paracucumaria hyndmani
- Pseudothyone raphanus
- Thyone fusus
-Thyone inermis
Subfamily Phyllophorinae
The Phyllophorinae are characterised by having 15-30 tentacles and include 3 representatives in the North Sea:
-Neopentadactyla mixta
-Thyonidium pellucidum
-Thyonidium commune