Oxynoidae

Thesse have an oval shell, and a very long thick tail. For defense, they secrete toxic/iritant chemicals, or, like a lizard, can shed part of their body, which keeps twitching while the animal crawls to safety.



Caliphyllidae

The best known genus here is Cyerce. These have flattened, often very colourful cerata which they move backwards and forwards like a butterflys' wing as they move.






Limapontiidae

Costastiella of "Sean the Sheep" fame, the colourful Stilliger spp. and the parasitic Ercolania spp. belong to this family.
They almost all have many cerata. Their "eyes" are located behind the rhinophores.










Plakobranchidae

In addition to Plakobranchus, Elysia and Thuridella belong to this family. They are all algae eaters that lack cerata.











