From Clay Bryce, WA Museum:
Spurilla neopolitana is a sea slug - it is an unwanted visitor to Australian shores. It has turned up along the east coast and may turn up here in our SW as it prefers temperate waters. If seen any information, photograph or specimen, would be greatly appreciated.
Distribution: Mediterranean, West Atlantic from Florida to Brazil. East Pacific (Baja California). See Spurilla sp. 1., a possible introduction to Japan & NOW EAST AUSTRALIA.
Spurilla neopolitana is a large species, around 60mm, that prefers the intertidal. Shipping harbours would be a very suitable habitat.