Dermatobranchus sp. 4.

Order: NUDIBRANCHIA
Suborder: ARMININA
Family: Arminidae

See Bob Bolland's message below.

Authorship details
Rudman, W.B., 1999 (December 12) Dermatobranchus sp. 4. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/dermsp4