It must be said that we know little about these beasts, other than that they have specially shaped rhinophores and no external gills.

Armina scotti

Quite a busy Nudibranch, which feeds on Sea Pens out on the sand. We've seen them in the day, although they are said to be nocturnal. Previously known as A. semperi

Dermatobranchus fortunata

Only one sighting so far; thank you Gabriele.

Dermatobranchus striatus

A very small Arminian, frequently spotted amongst the Octocoral species.