1, as designated by Gosliner, 1987, is a species of sea slug, specifically an aeolid nudibranch.
This species is endemic to the South African coast and is found only from the Atlantic coast of the Cape Peninsula to the eastern side of False Bay in 5–15 m of water.
It is a slender-bodied aeolid with a red head bearing perfoliate rhinophores and a pair of pale-tipped oral tentacles.
The nudibranch eats the hydroid and passes its nematocysts unharmed through its digestive system to the tips of its cerata.
It is probable that the bright colours of the black-dot nudibranch serve to advertise to predators that it is toxic.