Aplousobranchia is an order of ascidians that are almost exclusively colonial or compound. They include some of the most diverse groups of ascidians, including the didemnids and polyclinids. Many of these organisms are little-known and/or can only be reliably distinguished by microscopic examination, and are presented here by genus when ID to species is not practical.

Family Clavelinidae

Family Didemnidae

Family Holozoidae

Family Polycitoridae

Family Polyclinidae

Family Pseudodistomidae

Family Ritterllidae

Family Stomozoidae