Lahille, 1886
Except for the Cionidae, colony-forming enterogonid ascidians.
Body divided into thorax and abdomen, with a post-abdomen present or absent. Branchial sac (except for Cionidae) without folds, inner vessels or bars, but with simple horizontal membranes. Gut-loop in the abdomen. Gonad in abdomen or postabdomen.
In the North Sea the suborder is represented by the families:
- Family Cionidae
- Family Clavelinidae
- Family Didemnidae
- Family Polyclinidae